FLAME-RETARDANT POLYCARBONATE RESIN COMPOSITIONS

BACKGROUND

[0001] During melt impregnation of continuous fibers to produce unidirectional (UD) continuous fiber composite tape, a molten polymer is casted as a film on a moving bed of continuous fibers to ensure that the correct amount of polymer and the correct position of the film is applied on the continuous fiber bed. A property of low viscosity of the molten polymer is important for good impregnation of the polymer into the fibers. At the same time, a property of high melt strength is important for providing good film width stability, to help avoid necking or breakage of the film which can cause dry spots in the produced tape.

[0002] Regular polycarbonate resins are melt processed at 300 °C, 150 °C higher than the glass transition temperature (T _g ) of 145 °C. The high processing temperatures limit the compatibility of regular polycarbonate resins with other materials, such as in-mold decorating films and overmolding compounds, and are inefficient for melt impregnation.

[0003] KR 2011 0076547 is directed to a polycarbonate resin composition with good flame retardancy and transparency. The polycarbonate resin composition includes (A) 100 parts by weight of a base resin including (Al) 50-90 weight% of a linear polycarbonate resin and (A2) 10-50 weight% of a branched polycarbonate resin, (B) 5-20 parts by weight of oligomeric phosphoric acid ester compounds or mixture thereof induced from bisphenol-A, (C) 0.1-10 parts by weight of cyclic phosphagen compounds, and (D) phenyl group-substituted siloxane copolymers.

[0004] WO 2005/075568 is directed to a polycarbonate composition with thin wall flame retardance. These compositions contain a polycarbonate/siloxane component, containing a polycarbonate siloxane copolymer, or a mixture of a polycarbonate siloxane copolymer and polycarbonate resin; a mineral filler; and a flame retardant. The composition contains at least 50% by weight of polycarbonate when the polycarbonate of the polycarbonate siloxane copolymer and any polycarbonate resin (linear or branched) are considered together; and the polycarbonate siloxane copolymer and the mineral filler are present in amounts effective to achieve a flex modulus of 29,000 kg/cm ³ or greater, a room temperature Notched Izod Impact Strength of 25 kgf-cm/cm or greater. The composition also includes a flame retardant to enable the composition to obtain a UL94 rating of V0 at test thicknesses of 1.2 mm.

[0005] WO 2016/186100 is directed to a polycarbonate resin composition having flame retardancy and ability to impregnate continuous fiber reinforcement materials. The polycarbonate resin composition contains 60-88 mass% of a polycarbonate resin (A) and 12-40 mass% of a phosphorous-based flame retardant (B) wherein the polycarbonate resin composition has a flow value at 240°C of 9 to 120x0. Olcc/sec.

[0006] US 2014/371360 is directed to a flame retardant composition comprising a

polycarbonate; 5 to 10 weight percent of a polysiloxane-polycarbonate copolymer; where the polysiloxane-polycarbonate copolymer comprises an amount of greater than 10 weigh percent of the polysiloxane and where the molecular weight of the polysiloxane-polycarbonate copolymer is greater than or equal to 25,000 grams per mole; 5 to 20 weight percent of a branched polycarbonate; 5 to 60 weight percent of a reinforcing filler; and 1 to 15 weight percent of a flame retarding compound.

[0007] WO 2018/007335 is directed to a multilayer composite material containing one or more fiber layers of a fiber material and a matrix material based on an aromatic polycarbonate. The fiber layer(s) is/are embedded in the matrix material. A fiber composite comprising at least one layer of fibrous material embedded in an aromatic polycarbonate-based composition including A) aromatic polycarbonate, 1% to 14% by weight talc, and C) 7% by weight to 15% by weight of at least one of a particular cyclic phosphazene is disclosed therein.

[0008] US2018/0001577 is directed to a carbon-fiber reinforced resin composite having a variation of fiber areal weight of 10% or lower and a variation of fiber volume fraction of 15% or lower, and a weight average fiber length of 1 to 100 mm.

[0009] Conventional polymer carbonate resins fail to provide the combination of flame retardant properties, lower T _g , and a combination of high melt strength and low melt viscosity suitable for impregnation of fibers, such as to produce UD tape.

SUMMARY OF THE INVENTION

[0010] The present invention provides a flame-retardant polycarbonate composition including linear polycarbonate that is 20 wt% to 90 wt% of the polycarbonate composition. The polycarbonate composition includes branched polycarbonate that is 5 wt% to 30 wt% of the polycarbonate composition. The polycarbonate composition also includes phosphorus- containing flame retardant that is 5 wt% to 20 wt% of the polycarbonate composition.

[0011] The present invention also provides a fire-retardant polycarbonate fiber composite including the flame-retardant polycarbonate composition. The fire-retardant polycarbonate fiber composite also includes at least one layer of fibers therein. The fiber composite can be a flame- retardant unidirectional (UD) polycarbonate fiber composite tape, wherein the fibers of the at least one layer of fibers are aligned in the same direction.

[0012] The present invention provides a method of forming a fiber composite. The method includes combining the flame-retardant polycarbonate composition with at least one layer of fibers to form the fiber composite including the polycarbonate composition. The polycarbonate composition includes the at least one layer of fibers therein. The method can be any suitable method of fiber composite or fiber prepreg manufacturing, such as solvent impregnation, aqueous slurry, film stacking powder scattering, direct melt impregnation, or a combination thereof. The method can include extruding a film including the flame-retardant polycarbonate composition. The method includes contacting the film with at least one layer of fibers, to form the fiber composite that includes the polycarbonate composition. The method can form UD tape, wherein the fibers of the at least one layer of fibers are aligned in the same direction.

[0013] The flame-retardant polycarbonate composition, fiber composites and UD tapes formed therefrom, and methods of forming fibers composites and UD tapes therefrom, can have certain advantages over other flame-retardant polycarbonate compositions, fiber composites formed therefrom, and methods of making the same, at least some of which are unexpected. For example, the flame-retardant polycarbonate composition of the present invention can have a lower glass transition temperature (T _g ) than other flame-retardant polycarbonate compositions, such as closer to 100 °C, which can provide a more economical and practical polycarbonate composition for extrusion and for forming polycarbonate fiber composites such as UD tape.

[0014] The flame-retardant polycarbonate composition of the present invention can have a higher melt strength during extrusion of a film thereof, with less necking and less breakage of the film, as compared to other flame-retardant polycarbonate composition. By providing a higher melt strength, the flame-retardant polycarbonate composition can more effectively be used to form polycarbonate fiber composites such as UD tapes, such as providing fewer dry spots and even impregnation of the fibers at a higher line speed than possible with other flame- retardant polycarbonate compositions. Although decreasing the extrusion temperature of a polycarbonate composition can increase the melt strength thereof, for conventional compositions the lower extrusion temperature also results in an increase in melt viscosity, preventing the composition from effectively and efficiently penetrating fibers during formation of a

polycarbonate fiber composite such as a UD tape.

[0015] The flame-retardant polycarbonate composition of the present invention can have a lower melt viscosity than other flame-retardant polycarbonate compositions. A lower melt viscosity can allow the polycarbonate composition to better penetrate fibers during formation of a polycarbonate fiber composite such as a UD tape, forming better composites at a higher rate of speed than possible with other flame-retardant polycarbonate compositions. Although increasing the extrusion temperature of a polycarbonate composition can increase the melt flow viscosity thereof, for conventional compositions the higher extrusion temperature also results in decrease in melt strength, causing necking and film breakage, preventing the composition from effectively and efficiently being used to form a polycarbonate fiber composite such as UD tape.

[0016] The flame-retardant polycarbonate composition of the present invention has a balance of the properties of extruded film melt strength as well as melt flow viscosity, such that within a practical film extrusion temperature range, the composition has good melt strength with little to no necking or breakage of the extruded film, combined with good melt flow viscosity that provides thorough and rapid impregnation of the molten composition into fibers, allowing the flame-retardant polycarbonate composition to provide polycarbonate fiber composites with greater efficiency and of higher quality than possible with other flame-retardant polycarbonate compositions. The polycarbonate fiber composite of the present invention can have improved flame retardant properties combined with greater impact resistance and a lower occurrence of stress cracks as compared to other flame-retardant polycarbonate composites.

BRIEF DESCRIPTION OF THE FIGURES

[0017] The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments of the present invention.

[0018] FIG. 1 illustrates an end-on view of an example of the unidirectional tape.

[0019] FIG. 2 illustrates Vicat softening temperature versus flame-retardant content for various phosphate flame-retardants in a polycarbonate.

[0020] FIG. 3 illustrates melt viscosity versus branches polycarbonate content for a

polycarbonate resin.

[0021] FIGS. 4-8 are photographs of an extruded film of various polycarbonate resin compositions including a flame-retardant.

[0022] Fig. 9 is a scanning electron microscope (SEM) of a tape of Example 5.4 showing impregnation of the sample.

DETAILED DESCRIPTION OF THE INVENTION

[0023] Reference will now be made in detail to certain embodiments of the disclosed subject matter. While the disclosed subject matter will be described in conjunction with the enumerated claims, it will be understood that the exemplified subject matter is not intended to limit the claims to the disclosed subject matter.

[0024] Throughout this document, values expressed in a range format should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a range of “0.1% to 5%” or“0.1% to 5%” should be interpreted to include not just 0.1% to 5%, but also the individual values (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range.

[0025] In this document, the terms“a,”“an,” or“the” are used to include one or more than one unless the context clearly dictates otherwise. The term“or” is used to refer to a nonexclusive “or” unless otherwise indicated. The statement“at least one of A and B” or“at least one of A or B” has the same meaning as“A, B, or A and B.” In addition, it is to be understood that the phraseology or terminology employed herein, and not otherwise defined, is for the purpose of description only and not of limitation. Any use of section headings is intended to aid reading of the document and is not to be interpreted as limiting; information that is relevant to a section heading may occur within or outside of that particular section.

[0026] In the methods described herein, the acts can be carried out in any order without departing from the principles of the invention, except when a temporal or operational sequence is explicitly recited. Furthermore, specified acts can be carried out concurrently unless explicit claim language recites that they be carried out separately. For example, a claimed act of doing X and a claimed act of doing Y can be conducted simultaneously within a single operation, and the resulting process will fall within the literal scope of the claimed process.

[0027] The term“substantially” as used herein refers to a majority of, or mostly, as in at least 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least 99.999% or more, or 100%. The term“substantially free of’ as used herein can mean having none or having a trivial amount of, such that the amount of material present does not affect the material properties of the composition including the material, such that the composition is 0 wt% to 5 wt% of the material, or 0 wt% to 1 wt%, or 5 wt% or less, or having an upper limit of 4.5, 4, 3.5, 3, 2.5, 2, 1.5, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.01, or 0.001 wt%. The term “substantially free of’ can mean having a trivial amount of or having 0%.

[0028] The term“hydrocarbon” or“hydrocarbyl” as used herein refers to a molecule or functional group that includes carbon and hydrogen atoms. The term can also refer to a molecule or functional group that normally includes both carbon and hydrogen atoms but wherein all the hydrogen atoms are substituted with other functional groups. The term can refer to a funcnal group derived from a straight chain, branched, or cyclic hydrocarbon, and can be alkyl, alkenyl, alkynyl, aryl, cycloalkyl, acyl, or any combination thereof.

[0029] As used herein, the term“polymer” refers to a molecule having at least one repeating unit and can include copolymers.

[0030] The term“number-average molecular weight” (M _n ) as used herein refers to the ordinary arithmetic mean of the molecular weight of individual molecules in a sample. It is defined as the total weight of all molecules in a sample divided by the total number of molecules in the sample. Experimentally, M _n is determined by analyzing a sample divided into molecular weight fractions of species i having m molecules of molecular weight Mi through the formula M _n = åM,n, / ån,. The M _n can be measured by a variety of well-known methods including gel permeation chromatography, spectroscopic end group analysis, and osmometry. When gel permeation chromatography is used monodisperse polystyrene and/or polydisperse polycarbonate standards can be used to calibrate. If unspecified, molecular weights of polymers given herein are number- average molecular weights.

Flame-retardant polycarbonate composition.

[0031] The present invention provides a flame-retardant polycarbonate composition. The composition can include linear polycarbonate that is 20 wt% to 90 wt% of the flame-retardant polycarbonate composition. The linear polycarbonate can be one linear polycarbonate or multiple linear polycarbonates (e.g., having various molecular weight ranges). The composition can include branched polycarbonate that is 5 wt% to 30 wt% of the flame-retardant

polycarbonate composition. The branched polycarbonate can be one branched polycarbonate or multiple branched polycarbonates (e.g., having different molecular weight ranges or different types or degrees of branching). The composition can include phosphorus-containing flame retardant that is 5 wt% to 20 wt% of the flame-retardant polycarbonate composition. The phosphorus-containing flame retardant can be one flame retardant or multiple flame retardants.

[0032] The polycarbonate composition can have any suitable melt viscosity, such that conditions can be selected to effectively and efficiently form polycarbonate fiber composites such as UD tape using the polycarbonate composition. For example, the polycarbonate composition can have a melt viscosity measured at 275°C and 500 per second (l/s) of less than 200 Pascal seconds (Pa s), or less than 190 Pa s, or 25 Pa s to 199 Pa s, or 50 Pa s to 199 Pa s, or 100 Pa s to 199 Pa s, or 150 Pa s to 190 Pa s,. Melt viscosity can be measured, for example, according to ISO 11443 (2005).

[0033] The polycarbonate composition can have any suitable glass transition temperature, such that conditions can be selected to effectively and efficiently form polycarbonate fiber composites such as UD tape using the polycarbonate composition. For example, the

polycarbonate composition can have a T _g of 80 °C to 120 °C, or 90 °C to 110 °C, or 95 °C to 105 °C, or 96 to l02°C, or 96 to l00°C.“Tg” refers to a temperature at which an amorphous polymeric material changes from a hard, solid-like state into a viscous or elastic fluid-like state. Tg can be determined by differential scanning calorimetry according to ISOl 1357-1,2, and 3 (2011). Vicat softening temperature of the polycarbonate composition can be from 65 or from 70 or from 75 or from 80 or from 85 or from 90, or from 95, or from l00°C, up to 130, or up to 128, or up to 120, or up to 115, or up to 113 or up to l00°C according to ISO 306 at 50

Newtons, l20°C/hour. For example, with 5 to 20 wt% phosphorous flame retardant in the composition, the Vicat softening can be 65 to 130, or 65 to l28°C. For example, with 10 to 15 wt% phosphorous flame retardant in the composition, the Vicat softening can be 80 to 115, or 80 to 1 l3°C. For example, with 10 to 12 wt% phosphorous flame retardant in the composition, the Vicat softening can 90 to 115 or 90 to 1 l3°C.

[0034] The polycarbonate composition can have any suitable melt strength during extrusion of a film thereof, such that conditions can be selected to effectively and efficiently form

polycarbonate fiber composites such as UD tape using the polycarbonate composition. The melt strength can be measured visually during extrusion of the film; films that experience necking or film breakage have poor melt strength under the conditions measured. For example, during extrusion of the polycarbonate into a film having a thickness of 0.01 mm to 0.4 mm, or 0.025 mm to 0.2 mm, 0.025 mm to 0.1 mm(for example thickness can be 0.01, 0.02, 0.025, 0.03, 0.04, 0.05, 0.06, 0.08, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, or 0.4 mm), at an extrusion temperature of 230 °C to 280 °C (for example, 230,235, 240, 245, 250, 255, 260, 265, 270, 275 °C, or 280 °C), substantially no necking of the film occurs, substantially no breakage of the film occurs, or a combination thereof. The method can include extruding the film with a width of 1 mm to 2,000 mm, or 70 mm to 200 mm, 50 mm to 800 mm, (for example 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 40, 50, 75, 100, 125, 150, 175, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 800, 900, 1,000, 1,500, or 2,000 mm ). The extruded film can be formed using a line speed of at least 2 m/min, or at least 3.5 m/min, or 3.5 m/min to 10 m/min, (for example 2, 2.5 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, or 10.5 m/min).

Flame retardant.

[0035] The flame-retardant polycarbonate composition includes one or more flame retardants, including one or more phosphorus-containing flame retardants. The flame retardants in the polycarbonate composition give the polycarbonate composition flame retardant properties, such as sufficient for the polycarbonate composition, or a fiber composite thereof, such as to achieve a UL94 rating of V-0, or a rating of HB, V-2, V-l, V-0, 5VB, or 5VA.

[0036] The phosphorus-containing flame retardant in the polycarbonate composition can be one flame retardant or more than one flame retardant. The phosphorus-containing flame retardant can be a phosphate-containing flame retardant or a phosphazene flame retardant. The phosphorous -containing flame retardant can be resorcinol bis(diphenyl phosphate) (RDP), bisphenol A bis(diphenyl phosphate) (BPADP), an oligomeric bisphosphate ester flame retardant, or a combination thereof. The one or more phosphorus-containing flame retardants can be any suitable proportion of the polycarbonate composition, such as 5 wt% to 20 wt% of the flame-retardant polycarbonate composition, or 9 wt% to 15 wt%, or 10 wt% to 14 wt%, (for example 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 wt%) of the flame-retardant polycarbonate composition. This phosphorous-containing flame retardant can have a plasticizing effect. The weight ratio of the phosphorous-containing flame retardant to branched

polycarbonate can be as a lower limit of 0.3: 1, or a lower limit of 0.4: 1 to an upper limit of 2:1, or an upper limit of 1.5: 1 or an upper limit of 1 :l or an upper limit of 0.7: 1. For example, the ratio can be 0.5: 1. Weight ratios of 0.3: 1 to 1 : 1, particularly 0.4: 1 to 0.7: 1, or 0.5: 1 can facilitate impregnation when making the fiber composite from the composition.

[0037] In addition to the one or more phosphorus-containing fire-retardants, the flame-retardant polycarbonate composition can include secondary flame retardant (e.g., flame retardant that does not include phosphorus and that is different than the phosphorus-containing flame retardant).

The secondary flame retardant can be any suitable one or more flame retardants, such as including (e.g., as pure materials or as compounds including the materials) aluminum, polyphosphate, phosphorus, nitrogen, sulfur, silicon, antimony, chlorine, bromine, magnesium, zinc, carbon, or a combination thereof. Flame retardants can be halogen-containing flame retardants or non-halogenated flame retardants. The flame retardant can include expandable graphite, vermiculite, ammonium polyphosphate, alumina trihydrate (ATH), magnesium hydroxide (Mg(OH)2), aluminum hydroxide (Al(OH)3), molybdate compounds, chlorinated compounds, brominated compounds, antimony oxides, organophosphorus compounds, a filler or nanofiller (e.g., fumed silica, talcum, zin borate), or a combination thereof. The secondary flame retardant can be a perfluoroalkane sulfonate, such as potassium perfluorobutane sulfonate (Rimar salt). The one or more secondary flame retardants can form any suitable proportion of the polycarbonate composition, such 0 wt% to about 5 wt% (e.g., greater than 0 wt% to 5 wt%), or 0 wt% to 1 wt% (e.g., greater than 0 wt% to 1 wt%) of the flame-retardant polycarbonate composition (for example 0, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5 wt% of the flame-retardant polycarbonate composition).

Linear polycarbonate.

[0038] The flame-retardant polycarbonate composition includes linear polycarbonate. The linear polycarbonate can be one linear polycarbonate or more than one linear polycarbonate. The linear polycarbonate can be any suitable linear polycarbonate. The linear polycarbonate can have any suitable molecular weight, such as 10,000 Daltons to 45,000 Daltons, (for examples 10,000, 15,000, 20,000, 25,000, 30,000, 35,000, 40,000, or 45,000 Daltons).

[0039] As used herein, the terms“polycarbonate” and“polycarbonate resin” mean

polycarbonate polymers or copolymers including repeating structural carbonate units having the structure -R ¹ -0-C(0)-0-, wherein at least 60% of the total number of R ¹ groups are aromatic organic radicals and the balance thereof are aliphatic, alicyclic, or aromatic radicals. For example, each R ¹ can be an aromatic organic radical, such as a radical having the structure -A ¹ - Y'-A ² -, wherein each of A ¹ and A ² is a monocyclic divalent aryl radical and Y ¹ is a bridging radical having one or two atoms that separate A ¹ from A ² . Y ¹ can be a radical having one atom separating A ¹ from A ² . Illustrative non-limiting examples of radicals of this type are -0-, -S-, - S(O)-, -S(0 ₂ )-, -C(O)-, methylene, cyclohexylmethylene, 2-[2.2. l]-bicycloheptylidene, ethylidene, isopropylidene, neopentylidene, cyclohexylidene, cyclopentadecylidene,

cyclododecylidene, and adamantylidene. The bridging radical Y ¹ can be a hydrocarbon group or a saturated hydrocarbon group such as methylene, cyclohexylidene, or isopropylidene.

[0040] Polycarbonates can be produced by the interfacial reaction or melt reaction of dihydroxy compounds having the formula HO-R'-OH, which includes dihydroxy compounds having the structure HO-A^Y^OH, wherein Y ¹ , A ¹ and A ² are as described above. Also included are bisphenol compounds having the structure:

wherein R ^a and R ^b each represent a halogen atom or a monovalent hydrocarbon group and can be the same or different; p and q are each independently integers of 0 to 4; and X ^a represents one of the groups:

wherein R ^c and R ^d each independently represent a hydrogen atom or a monovalent linear or cyclic hydrocarbon group that is optionally halogenated and R ^e is a divalent hydrocarbon group.

[0041] Some illustrative, non-limiting examples of suitable dihydroxy compounds include the following: resorcinol, hydroquinone, 4,4'-dihydroxybiphenyl, l,6-dihydroxynaphthalene, 2,6- dihydroxynaphthalene, bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)diphenylmethane, bis(4-hydroxyphenyl)-l-naphthylmethane, l,2-bis(4-hydroxyphenyl)ethane, 1, l-bis(4- hydroxyphenyl)-l-phenylethane, 2-(4-hydroxyphenyl)-2-(3-hydroxyphenyl)propane, bis(4- hydroxyphenyl)phenylmethane, 1 , 1 -bis(hydroxyphenyl)cyclopentane, 1 , 1 -bis(4- hydroxyphenyl)cyclohexane, 1 , 1 -bis(4-hydroxyphenyl)isobutene, 1 , 1 -bis(4- hydroxyphenyl)cyclododecane, trans-2,3-bis(4-hydroxyphenyl)-2-butene, 2,2-bis(4- hydroxyphenyl)adamantine, (alpha, alpha '-bis(4-hydroxyphenyl)toluene, bis(4- hydroxyphenyl)acetonitrile, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(3-ethyl-4- hydroxyphenyl)propane, 2,2-bis(3-n-propyl-4-hydroxyphenyl)propane, 2,2-bis(3-isopropyl-4- hydroxyphenyl)propane, 2,2-bis(3-sec-butyl-4-hydroxyphenyl)propane, 2,2-bis(3-t-butyl-4- hydroxyphenyl)propane, 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane, 2,2-bis(3-allyl-4- hydroxyphenyl)propane, 2,2-bis(3-methoxy-4-hydroxyphenyl)propane, 2,2-bis(4- hydroxyphenyl)hexafluoropropane, l,l-dichloro-2,2-bis(4-hydroxyphenyl)ethylene, 4,4'- dihydroxybenzophenone, 3,3-bis(4-hydroxyphenyl)-2-butanone, l,6-bis(4-hydroxyphenyl)-l,6- hexanedione, ethylene glycol bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)ether, bis(4- hydroxyphenyl) sulfide, bis(4-hydroxyphenyl) sulfoxide, bis(4-hydroxyphenyl)sulfone, 9,9-bis(4- hydroxyphenyl)fluorine, 2, 7-dihydroxypyrene, 6,6 '-dihydroxy-3 ,3,3 ',3 '- tetramethylspiro(bis)indane (“spirobiindane bisphenol”), 3,3-bis(4-hydroxyphenyl)phthalide, 2,6-dihydroxydibenzo-p-dioxin, 2,6-dihydroxythianthrene, 2,7-dihydroxyphenoxathin, 2,7- dihydroxy-9, lO-dimethylphenazine, 3,6-dihydroxydibenzofuran, 3,6- dihydroxydibenzothiophene, and 2,7-dihydroxycarbazole, and the like, as well as combinations including at least one of the foregoing dihydroxy compounds.

[0042] Specific examples of the types of bisphenol compounds that can be represented by the structure HO-A^Y^OH include l,l-bis(4-hydroxyphenyl)methane, l,l-bis(4- hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl) propane (hereinafter“bisphenol A” or “BP A”), 2,2-bis(4-hydroxyphenyl) butane, 2,2-bis(4-hydroxyphenyl) octane, l,l-bis(4- hydroxyphenyl) propane, l,l-bis(4-hydroxyphenyl) n-butane, 2,2-bis(4-hydroxy-l- methylphenyl) propane, l,l-bis(4-hydroxy-t-butylphenyl) propane, or a combination thereof.

The polycarbonate can be a linear homopolymer derived from bisphenol A, in which each of A ¹ and A ² is p-phenylene and Y ¹ is isopropylidene.

[0043] All types of polycarbonate end groups are contemplated as being useful, provided that such end groups do not significantly affect desired properties of the polycarbonate composition.

An end-capping agent (also referred to as a chain-stopper) can be used to limit molecular weight growth rate, and so control molecular weight of the first and/or second polycarbonate. The end group can be derived from the carbonyl source (e.g., the diary! carbonate), from selection of monomer ratios, incomplete polymerization, chain scission, and the like, as well as any added end-capping groups, and can include derivatizabie functional groups such as hydroxy groups, carboxylic acid groups, or the like. The end group of a polycarbonate can be derived from a diaryl carbonate. Exemplary chain-stoppers include a monophenolic compound (e.g., phenyl compounds having a single free hydroxy group), a monoearboxy!ic acid chloride, a

monoch!oroformate, or a combination thereof Examples of phenolic chain-stoppers include phenol and C1-C22 alkyl-substituted phenols such as p-cumylphenoi (PCP), resorcinol monobenzoate, and p-ierti ary- butyl phenol, cresol, and monoethers of diphenols, such as p- methoxyphenol. Alkyl-substituted phenols with branched chain alkyl substituents having 8 to 9 carbon atoms can be used. The end group can be derived from an activated carbonate, such as from the transesterifi cation reaction of the alkyl ester of an appropriately substituted activated carbonate with a hydroxy group at the end of a polycarbonate polymer chain under conditions in which the hydroxy group reacts with the ester carbonyl from the activated carbonate instead of with the carbonate carbonyl of the activated carbonate. In this way, structural units derived from ester containing compounds or substructures derived from the activated carbonate and present in the melt polymerization reaction can form ester end groups. The ester end group derived from a salicylic ester can be a residue of BMSC or other substituted or unsubstituted bis(alkyl salicyl) carbonate such as bistetbyl salicyl) carbonate, bis(propyl salicyl) carbonate, bis(phenyl salicyl) carbonate, bisibenzyl salicyl) carbonate, or the like. The end group can be derived from and is a residue of activated carbonate source bismethylsalicyl carbonate (BMSC), and is an ester end group derived from a salicylic acid ester (salicylate). In an example, the polycarbonate can be made by a melt process and can have a ratio of phenol end groups to total end groups in % (OH+Phenol) < 50%, such as < 80%, or 80 to < 100%, or 80 to 95%.

[0044]“Polycarbonates” and“polycarbonate resins” as used herein can include copolymers including carbonate chain units. A specific suitable copolymer is a polyester carbonate, also known as a copolyester-polycarbonate, including in addition to recurring carbonate chain units having the structure -R ¹ -0-C(0)-0-, repeating units having the structure -C(0)-T-C(0)-0-D-0-, wherein D is a divalent radical derived from a dihydroxy compound, and can be, for example, a C2-10 alkylene radical, a C6-20 alicyclic radical, a C6-20 aromatic radical or a polyoxyalkylene radical in which the alkylene groups contain 2 to 6 carbon atoms, specifically 2, 3, or 4 carbon atoms; and T is a divalent radical derived from a dicarboxylic acid, and can be, for example, a C2-10 alkylene radical, a C6-20 alicyclic radical, a C6-20 alkyl aromatic radical, or a C6-20 aromatic radical.

[0045] D can be a C2-6 alkylene radical. D can be derived from an aromatic dihydroxy compound having the structure:

wherein each R ^f is independently a Ci-io hydrocarbon group and n is 0 to 4. The halogen is usually bromine. Examples of such compounds include resorcinol, substituted resorcinol compounds such as 5-methyl resorcinol, 5-ethyl resorcinol, 5-propyl resorcinol, 5-butyl resorcinol, 5-t-butyl resorcinol, 5-phenyl resorcinol, 5-cumyl resorcinol; catechol;

hydroquinone; substituted hydroquinones such as 2-methyl hydroquinone, 2-ethyl

hydroquinone, 2-propyl hydroquinone, 2-butyl hydroquinone, 2-t-butyl hydroquinone, 2-phenyl hydroquinone, 2-cumyl hydroquinone, 2,3,5,6-tetramethyl hydroquinone, 2,3,5,6-tetra-t-butyl hydroquinone; or combinations including at least one of the foregoing compounds.

[0046] Examples of aromatic dicarboxylic acids that can be used to prepare the polyesters include isophthalic or terephthalic acid, l,2-di(p-carboxyphenyl)ethane, 4,4’-dicarboxydiphenyl ether, 4,4’-bisbenzoic acid, and mixtures including at least one of the foregoing acids. Acids containing fused rings can also be present, such as in 1,4-, 1,5-, or 2,6-naphthalenedicarboxylic acids. Specific dicarboxylic acids are terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, cyclohexane dicarboxylic acid, or mixtures thereof. A specific dicarboxylic acid includes a mixture of isophthalic acid and terephthalic acid wherein the weight ratio of terephthalic acid to isophthalic acid is 10: 1 to 0.2:9.8. D can be a C2-6 alkylene radical and T is p-phenylene, m-phenylene, naphthalene, a divalent cycloaliphatic radical, or a mixture thereof. This class of polyester includes poly(alkylene terephthalates).

[0047] Another example of a polycarbonate copolymer is a polysiloxane-polycarbonate, including in addition to the carbonate chain units repeating units having the structure -O- Si(R ^c )(R ^d )- wherein R ^c and R ^d are as defined above. Such copolymers can be derived from a siloxane-containing dihydroxy compound, wherein a linker group such as aryl, alkyl, alkoxy, aryloxy, polyalkoxy, or any combination thereof (e.g., arylalkyl, arylalkylaryl, arylalkylaryloxy (e.g., bisphenol-derived)) can occur between the siloxane groups and the hydroxy groups and can become part of the copolymer at the ends of the polysiloxane block.

[0048] Suitable polycarbonates can be manufactured by processes such as interfacial polymerization and melt polymerization. Although the reaction conditions for interfacial polymerization can vary, an exemplary process generally involves dissolving or dispersing a dihydric phenol reactant in aqueous caustic soda or potash, adding the resulting mixture to a suitable water-immiscible solvent medium, and contacting the reactants with a carbonate precursor in the presence of a suitable catalyst such as triethylamine or a phase transfer catalyst, under controlled pH conditions, e.g., 8 to 10. The most commonly used water-immiscible solvents include methylene chloride, l,2-dichloroethane, chlorobenzene, toluene, and the like. Suitable carbonate precursors include, for example, a carbonyl halide such as carbonyl bromide or carbonyl chloride, or a haloformate such as a bishaloformate of a dihydric phenol (e.g., the bischloroformates of bisphenol A, hydroquinone, or the like) or a glycol (e.g., the

bishaloformate of ethylene glycol, neopentyl glycol, polyethylene glycol, or the like).

Combinations including at least one of the foregoing types of carbonate precursors can also be used. Rather than utilizing the dicarboxylic acid per se, it is possible, and sometimes even preferred, to employ the reactive derivatives of the acid, such as the corresponding acid halides, in particular, the acid dichlorides and the acid dibromides. Thus, for example, instead of using isophthalic acid, terephthalic acid, or mixtures thereof, it is possible to employ isophthaloyl dichloride, terephthaloyl dichloride, and mixtures thereof.

[0049] Among the phase transfer catalysts that can be used are catalysts of the formula

(R ³ ) ₄ Q ⁺ X, wherein each R ³ is the same or different, and is a Ci-io alkyl group; Q is a nitrogen or phosphorus atom; and X is a halogen atom or a Ci _-8 alkoxy group or C ₆ -i ₈₈ aryloxy group.

Suitable phase transfer catalysts include, for example, [CH ₃ (CH ₂ ) ₃ ] ₄ NX, [CH ₃ (CH ₂ ) ₃ ] ₄ PX,

[CH ₃ (CH ₂ ) ₅ ]4NX, [CH ₃ (CH ₂ ) ₆ ]4NX, [CH ₃ (CH ₂ ) ₄ ] ₄ NX, CH ₃ [CH ₃ (CH ₂ ) ₃ ] ₃ NX, and

CH ₃ [CH ₃ (CH ₂ ) ₂ ] ₃ NX, wherein X is Cl-, Br , a Ci- ₈ alkoxy group or a C ₆ -i ₈₈ aryloxy group. An effective amount of a phase transfer catalyst can be 0.1 to 10 wt% based on the weight of bisphenol in the phosgenation mixture. An effective amount of phase transfer catalyst can be 0.5 to 2 wt% based on the weight of bisphenol in the phosgenation mixture.

[0050] Alternatively, melt processes can be used to make the polycarbonates. Generally, in the melt polymerization process, polycarbonates can be prepared by co-reacting, in a molten state, the dihydroxy reactant(s) and a diaryl carbonate ester, such as diphenyl carbonate, in the presence of a transesterification catalyst in a Banbury® mixer, twin screw extruder, or the like to form a uniform dispersion. Volatile monohydric phenol is removed from the molten reactants by distillation and the polymer is isolated as a molten residue.

[0051] The one or more linear polycarbonates can be any suitable proportion of the

polycarbonate composition, such as 20 wt% to 90 wt% of the flame-retardant polycarbonate composition, or 55 wt% to 85 wt%, or 60 wt% to 80 wt%, (for example, 20, 25, 30, 35, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, or 90 wt%) of the flame-retardant polycarbonate composition.

[0052] The linear polycarbonate can include one or more low molecular weight polycarbonates, one or more high molecular weight polycarbonates, or a combination thereof. The low molecular weight linear polycarbonate can have a molecular weight of less than 25,000 Daltons, or 10,000 Daltons to less than 25,000 Daltons, or 15,000 Daltons to less than 25,000 Daltons, (for example, 2,000 Daltons, 4,000, 6,000, 8,000, 10,000, 12,000, 14,000, 16,000, 18,000, 20,000, 22,000, or 24,000 Daltons). The high molecular weight linear polycarbonate can have a molecular weight of 25,000 Daltons or more, such as 25,000 Daltons to 45,000 Daltons, or 25,000 Daltons to 35,000 Daltons, (for example, 26,000, 28,000, 30,000, 32,000, 34,000,

36,000, 38,000, 40,000, 42,000, 44,000, or 45,000 Daltons).

[0053] The linear polycarbonate in the polycarbonate composition can include a weight ratio of high molecular weight polycarbonate to low molecular weight polycarbonate of 1 : 1 to 1 : 100, or 1 :5 to 1 : 10, or 1 :6 to 1 :8, (for example, 1 : 1, 1 :2, 1 :3, 1 :4, 1 :5, 1 :6, 1 :6.5, 1 :7, 1 :7.5, 1 :8, 1 :9,

1 : 10, 1 : 15, 1 :20, 1 :30, 1 :40, 1 :50, 1 :75, or 1 : 100. [0054] One or more low molecular weight linear polycarbonates can form any suitable proportion of the polycarbonate composition, such as 0 wt% to 90 wt% of the polycarbonate composition, or 60 wt% to 80 wt%, or 0 wt%, (for example, 2, 4, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, or 90 wt%) of the flame-retardant polycarbonate composition. One or more high molecular weight linear polycarbonates can form any suitable proportion of the polycarbonate composition, such as 0 wt% to 90 wt% of the polycarbonate composition, or 8 wt% to 10 wt% of the flame-retardant polycarbonate composition, (for example, or 0, 1 , 2, 3, 4, 5, 6, 7, 7.5, 8, 8.5, 9, 9.5, 10, 11, 12, 14, 15, 16, 18, 20, 22, 24, 26, 28, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90 wt% of the flame-retardant polycarbonate composition).

Branched polycarbonate.

[0055] The flame-retardant polycarbonate composition includes branched polycarbonate. The branched polycarbonate can be one branched polycarbonate or more than one branched polycarbonate. The branched polycarbonate can be any suitable branched polycarbonate, which can be a polycarbonate polymer or copolymer formed from the same materials as a linear polycarbonate but further including branching agents such as triphenols or tetraphenols, or polyfunctional organic compounds containing at least three functional groups selected from hydroxyl, carboxyl, carboxylic anhydride, haloformyl, and mixtures of the foregoing functional groups. Specific examples of branching agents include trimellitic acid, trimellitic anhydride, trimellitic trichloride, tris-p-hydroxy phenyl ethane (THPE), isatin-bis-phenol, tris-phenol TC (l,3,5-tris((p-hydroxyphenyl)isopropyl)benzene), tris-phenol PA (4(4(1, l-bis(p-hy droxyphenyl)- ethyl) alpha, alpha-dimethyl benzyl)phenol), 4-chloroformyl phthalic anhydride, trimesic acid, and benzophenone tetracarboxylic acid. The branching agents can be used at a concentration of 0.05 wt% to 2 wt% of the branched polycarbonate. The branched polycarbonate can have a molecular weight of 20,000 Daltons to 40,000 Daltons, or 25,000 Daltons to 40,000 Daltons, or 30,000 Daltons to 35,000 Daltons.

[0056] The one or more branched polycarbonates can be any suitable proportion of the flame- retardant polycarbonate composition. For example, the one or more branched polycarbonates can be 5 wt% to 30 wt% of the flame-retardant polycarbonate composition, or 8 wt% to 28 wt%, or 10 wt% to 24 wt%, (for example 5,6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 2, or 30 wt%) of the flame-retardant polycarbonate composition. Other components.

[0057] The flame-retardant polycarbonate composition can optionally include one or more other components. For example, the flame-retardant polycarbonate composition can include a mold release agent, a thermal stabilizer, or a combination thereof.

[0058] A mold release agent can be any suitable mold release agent that enhances removal of the composition from a mold or from other components contacting the composition at the time of its solidification or cooling. The mold release agent can be a triacylglyceride release agent; a poly-alpha-olefm; epoxidized soybean oil; a silicone, including silicone oils; an ester, for example, fatty acid esters such as alkyl stearyl esters, e.g., methyl stearate; stearyl stearate, pentaerythritol tetrastearate, and the like; mixtures of methyl stearate and hydrophilic and hydrophobic nonionic surfactants including polyethylene glycol polymers, polypropylene glycol polymers, and copolymers thereof, e.g., methyl stearate and polyethylene-polypropylene glycol copolymers in a suitable solvent; a wax such as beeswax, montan wax, paraffin wax or the like; or a combination thereof. The mold release agent can be pentaerythritol stearate (PETS). The mold release agent can be any suitable proportion of the polycarbonate composition, such as 0 wt% to 20 wt% or 0.1 wt% to 5 wt% of the flame-retardant polycarbonate composition, , (for example, 0%, 0.1 wt%, 0.2, 0.4, 0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 8, 10, 12, 14, 16, 18, or 20 wt% of the flame-retardant polycarbonate composition).

[0059] A thermal stabilizer can be any suitable thermal stabilizer, such as any thermal stabilizer described in WO2015052110. The thermal stabilizer can be a phosphite, a phosphonate, or a phosphine. The thermal stabilizer can be triphenylphosphine (TPP), a trialkylphenyl phosphine, bisdiphenylphosphino-ethane, trinaphthyl phosphine, triphenyl phosphite, diphenyl,

phenyldialkyl phosphite, tris(nonylphenyl) phosphite, trilauryl phosphite, triphenyl phosphine (TPP), or IRGAFOS™ 168 (tris-(2,4-di-tert-butyl-phenyl)phosphite). The thermal stabilizer can be a phenolic antioxidant, such as an alkylated monophenol, an alkylated thioalkylphenol, a hydroquinone, or an alkylated hydroquinone. IRGANOX 1010 (pentaerythritol 3-(4-hydroxy- 3,5-di~tert-buiy]phenyl)propionate) or IRGANOX 1076 (2,6-di-tert~butyl-4~

(octadecanoxycarbonylethyi)phenol). The thermal stabilizer can be tris(di-t- butylphenyl)phosphite (TBPP). The thermal stabilize can be any suitable proportion of the polycarbonate composition, such as 0 wt% to 0.2 wt% (e.g., greater than 0 wt% to 0.2 wt%) of the flame-retardant polycarbonate composition, (for example, 0%, 0.001, 0.005, 0.01, 0.02, 0.04, 0.06, 0.08, 0.1, 0.12, 0.14, 0.16, 0.18, or 0.2 wt% of the flame-retardant polycarbonate composition).

[0060] The linear polycarbonate, branched polycarbonate, phosphorus-containing flame retardants, optional secondary flame retardant (if present), optional mold release agent (if present), and optional thermal stabilizer (if present), can be 100 wt% of the polycarbonate composition. The linear polycarbonate, branched polycarbonate, phosphorus-containing flame retardants, optional secondary flame retardant (if present), optional mold release agent (if present), and optional thermal stabilizer (if present) can be less, than 100 wt% of the

polycarbonate composition and other suitable components can form the remainder of the composition.

[0061] The flame-retardant polycarbonate composition can be free of or substantially free of fillers (e.g. reinforcing fillers), such as mineral fillers (e.g. clay), talc, glass fibers, carbon fibers. The flame-retardant polycarbonate composition can comprise no more than 1 wt%, or no more than 0.75 wt% or no more than 0.5 wt% of fillers, exemplified by talc, clay and glass fibers, of the flame-retardant polycarbonate composition.

Fire-retardant polycarbonate fiber composite.

[0062] The present invention can provide a fire-retardant polycarbonate fiber composite. The fiber composite includes the flame-retardant polycarbonate composition described herein (e.g., in a solidified non-flowable state) wherein the polycarbonate composition includes at least one layer of fibers therein. The fiber composite is generally in the shape of a planar layer, such as a piece of fabric or tape, and can be flexible or rigid. The fiber composite can be any suitable fiber composite, such as a prepreg, or a tape.

[0063] The fiber composite can include one layer of fibers, or multiple layers of fibers (e.g., 2,

3, 4, 5, 6, 7, 8, 9, or 10 or more layers). The polycarbonate composition can encapsulate the at least one layer of fibers. The polycarbonate composition can be a matrix that includes the at least one layer of fibers. The fiber composite can have any suitable thickness, such as 25 micrometers to 2 mm, 50 micrometers to 2 mm, or 50 micrometers to 400 micrometers. The standard deviation of thickness in a composite can be less than 0.05, or less than, or equal to 0.03 mm.

The coefficient of variability (defined as 100 times the standard deviation of a measurement or value divided by the average of the measurement or the value) can be less than 15%. For example, the fiber composite can have a thickness of 0.1 to 0.15 mm with a standard deviation of the thickness can be less than 0.05, or less than 0.03 mm.

[0064] Each layer of fibers in the fiber composite can independently be formed of fibers that are oriented in substantially the same direction (e.g., unidirectionally oriented fibers) or in random directions. Each layer of fibers can independently include any one or more suitable fibers, such as glass fibers, carbon fibers, ceramic fibers, aramid fibers, polymeric fibers (e.g., Kevlar, polyester), basalt fibers, natural fibers (e.g., flax fiber, hemp fiber, cotton fiber, wood fiber), metallic fibers (e.g., steel fiber, aluminum fiber), or a combination thereof. The fibers can be carbon fibers. If more than one layer is present, the layers of fibers can include the same or different types or blends of fibers.

[0065] The areal weight of the flame retardant polycarbonate fiber composite can be relevant particularly for composites in the form of sheets, films, tapes, and the like. The areal weight is the weight per unit area of the composite. The areal weight of the flame retardant polycarbonate fiber composite can be in a range having a lower limit of: 50 or 100 or 130 or 140 grams per square meter (g/m ² ) and an upper limit of: 3,000, or 2,500, or 2,000, or 1,500 or 1,000, or 500, or 400, or 300, or 200 g/m ² _. For example, the flame-retardant polycarbonate fiber composite can have an areal weight of 50 to 2,000 g/m ² , or 140 to 200 g/m ² . The areal weight can have a standard deviation in a composite of less than 10, or less than 5, or less than 2 g/m ² . The coefficient of variability can be less than 2%, or less than 1%.

[0066] The one or more layers of fibers can form a proportion of the overall volume of the polycarbonate fiber composite. For example, the fiber in the polycarbonate fiber composite can be 1 volume percent (vol%) to 80 vol% of the polycarbonate fiber composite, 40 vol% to 70 vol%, or 50 vol% to 60 vol%, (for example 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55,

60, 65, 70, 75, or 80 vol%). For example, the fiber volume fraction (FVF) of the polycarbonate fiber composite can be at least 40%, or at least 45%, or at least 50%. The FVF of the

polycarbonate fiber composite can be up to 70%, or up to 60%. For example, the FVF of the polycarbonate fiber composite can be 40% to 70%, or 45% to 60%. The standard deviation of the FVF of the polycarbonate fiber composite can be less than 10%, or less than 5%, or less than 4%, or less than 3%. The coefficient of variability of FVF can be less than 6 or less than 5.5 or less than 5%.

[0067] The polycarbonate fiber composite can have a fiber weight fraction, such as 1 wt% to 80 wt%, e.g., 6 wt% to 70 wt%, or 20 wt% to 65 wt% of the fiber composite (for example 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, or 80 wt%) based on total weight of the polycarbonate fiber composite.

[0068] The flame-retardant polycarbonate composition can form a proportion of the overall volume of the polycarbonate fiber composite. For example, the polycarbonate composition can be 20 vol% to 99 vol% of the polycarbonate fiber composite (for example, or 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 99 vol% or more of the polycarbonate fiber composite).

Unidirectional tape.

[0069] The present invention can provide a fire-retardant polycarbonate unidirectional (UD) fiber composite tape. The UD tape includes the flame-retardant polycarbonate composition described herein, wherein the polycarbonate fiber composite includes at least one layer of fibers therein, wherein the fibers of the at least one layer of fibers are oriented in the same direction (e.g., substantially in the same direction). The fibers are embedded in the polycarbonate composition. The polycarbonate composition encapsulates the fibers. The polycarbonate composition forms a matrix that encompasses the fibers. The fibers can be any suitable fiber described herein. The fibers can be carbon fibers.

[0070] The UD tape can have any suitable thickness, such as 25 micrometers (pm) to 2 mm, or 50 micrometers to 2 mm, or 50 micrometers to 400 micrometers, or 100 to 200 micrometers, or 140 to 160 micrometers, (for example 25, 30, 40, 50, 60, 80, 100, 120, 140, 150, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, or 950 micrometers, or 1 mm, 1.5 mm, or 2 mm. The UD tape can have any suitable width, such as 1 mm to 2,000 mm, 50 mm to 800 mm, (for example 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 40, 50, 75, 100, 125, 150, 175, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 800, 900, 1,000, 1,500, or 2,000 mm ). The standard deviation of thickness in the UD tape can be less than 0.05, or less than 0.03 mm. The coefficient of variability (defined as 100 times the standard deviation of a measurement or value divided by the average of the measurement or the value) can be less than 15%. For example, the UD tape can have a thickness of 0.1 to 0.15 mm with a standard deviation of the thickness can be less than 0.05, or less than 0.03 mm.

[0071] The areal weight of the UD tape can be in a range having a lower limit of 50, or 100, or 130, or 140 grams per square meter (g/m ² ) and an upper limit of 3000 or 2500 or 2000 or 1500 or 1000 of 500 or 400 or 300 or 200 g/m ² _. For example, the UD tape can have an areal weight of 140 to 200 grams per square meter (g/m ² ). The areal weight can have a standard deviation in a UD tape of less than 10 or less than 5 or less than 2 g/m ² . The coefficient of variability can be less than 2 or less than 1%.

[0072] The UD tape can have any suitable fiber volume fraction, such as 1 vol% to 80 vol%, 40 vol% to 70 vol%, or 50 vol% to 60 vol%,(for example 1, 2 , 4, 6, 8, 10, 15, 20, 25, 30, 35, 40,

42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 75, or 80 vol%. For example, the UD tape can have a fiber volume fraction of the fiber volume fraction (FVF) can be at least 40 or at least 45 or at least 50%. The FVF of the tape can be up to 70 or up to 60%. The standard deviation of the FVF of the UD tape can be less than 10 or less than 5 or less than 4 or less than 3%. The coefficient of variability of FVF of the UD tape can be less than 6 or less than 5.5 or less than 5%.

[0073] The UD tape can have any suitable fiber weight fraction, such as 1 wt% to 80 wt% (for example, 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, or 80 wt%)based on total weight of the UD tape.

[0074] The UD tape can have a volume fraction of the polycarbonate composition of 20 vol% to 99 vol%, 30 vol% to 60 vol%, or 40 vol% to 50 vol%, (for example, or 20, 25 , 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 99 vol%) based on total volume of the tape..

[0075] The UD tape can have a void fraction (i.e., volume percent void space) of 0 to 5%, 0 to 2%, O to 1%, (for example, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5,

1.6, 1.7, 1.8, 1.9, 2, 2.5, 3, 3.5, 4%, or 5%.

Method of forming a fiber composite or unidirectional tape.

[0076] The present invention provides a method of forming a fiber composite. The method can be any suitable method of forming the fiber composite described herein including the flame- retardant polycarbonate composition and at least one layer of fibers. The method can include combining the flame-retardant polycarbonate composition with at least one layer of fibers to form the fiber composite including the polycarbonate composition. The polycarbonate composition includes the at least one layer of fibers therein. The method can be any suitable method of fiber composite or fiber prepreg manufacturing, such as solvent impregnation (dissolving the polymer in solvent or adding solvent to the polymer to decrease its viscosity prior to impregnation with the diluted polymer followed by evaporation of the solvent), aqueous slurry (e.g., using an aqueous slurry of polymer particles to impregnate layers of fibers, followed by consolidation), film stacking (e.g., stacking of layers of polymer film with layers of fibers, followed by consolidation), powder scattering (e.g., dry powder impregnation, followed by consolidation), direct melt impregnation, or a combination thereof.

[0077] The method of forming a fiber composite can include extruding a film including an embodiment of the flame-retardant polycarbonate composition. The method can also include contacting the extruded film while it is a hot melt with at least one layer of fibers, to form the polycarbonate fiber composite described herein that includes the at least one layer of fibers therein.

[0078] The method can include forming the fiber composite at a speed of at least 2 m/min, or at least 3.5 m/min, or 3.5 m/min to 10 m/min, (for example, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, or 10.5 m/min). The method can include using an extrusion temperature of 200 °C to 310 °C, 230 °C to 280 °C, (for example, or 200, 210, 220, 230, 235, 240, 245, 250,

255, 260, 265, 270, 275, 280, 290, 300, or 310 °C). The method can include extruding the film with a thickness of 0.01 mm to 1 mm, or 0.025 mm to 0.1 mm, or 0.1 mm to 0.4 mm, (for example 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.6, 0.8, or 1 mm). The method can include extruding the film with a width of 1 mm to 2,000 mm, or 70 mm to 200 mm, 50 mm to 800 mm, (for example 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 40, 50, 75, 100, 125, 150, 175, 200,

250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 800, 900, 1,000, 1,500, or 2,000 mm). During the extrusion of the film, the film can be substantially free of necking, breakage, or both.

[0079] The ratio of the speed of the hot melt film to the speed of the fibers can be at least 1.5: 1 or at least 2: 1. For example, when extruding at a linear die opening of 0.1 mm, the speed of the polymer melt can be 0.5 to 0.6 times the speed of the fibers. As another example, when extruding at a linear die opening of 0.2 mm, the speed of the polymer melt can be 0.2 to 0.3 times the speed of the fibers. As yet another example, when extruding at a linear die opening of 0.3 mm, the speed of the polymer melt can be 0.1 to 0.2 times the speed of the fibers.

[0080] The method of forming the fiber composite is a method of forming a polycarbonate unidirectional fiber composite tape, wherein the fibers of the at least one layer of fibers contacted with the flame-retardant polycarbonate composition are aligned in the same direction. The method can be SABIC’s HPFIT™ method. The method can be a method described in U.S. patent publication no. 2018/0043580. FIG. 1 illustrates an example of a unidirectional tape 100, viewed along the longitudinal axis, showing unidirectional fiber layer 110 and extruded flame- retardant polycarbonate composition polycarbonate film 120. The polycarbonate composition 120 includes the unidirectional layer of fibers 110 therein.

EXAMPLES

[0081] The present invention can be better understood by reference to the following which are offered by way of illustration, and are non-limiting.

Example A Effect of polycarbonate plasticization by flame retardant agents.

[0082] Phosphates such as Bisphenol A bis(diphenyl phosphate) (BPADP), resorcinol bis (diphenyl phosphate) (RDP), and SOLDP (a proprietary oligomeric phosphate additive supplied by ICL Industrial Products) are effective plasticization agents for a mixture of polycarbonate resins as exemplified in FIG. 2, which illustrates Vicat softening temperature versus flame- retardant content for various phosphate flame-retardants in various mixtures of polycarbonates PC A, PC B, PC E, and PC G (shown in Table 1). The flame-retardant type and loading affected the Vicat and T _g values of the blend, while variation of the types of polycarbonates in the blend did not affect these values. The softening point obtained through Vicat measurements correlates well with the glass transition temperature in amorphous resins.

[0083] In order to achieve a glass transition of 100 °C, 10 wt% RDP or 12 wt% SOLDP or 14 wt% BPADP was added to a polycarbonate-based resin formulation.

Example B Effect of molecular weight and branching on melt viscosity.

[0084] Polycarbonate resins can be of a linear or branched architecture with various molecular weight. The lower the molecular weight of a given polymer architecture, generally, the lower the melt viscosity. Table 1 illustrates a list of various polycarbonate resins.

[0085] Table 1 : Overview of various polycarbonate resins.

[0086] FIG. 3 illustrates melt viscosity versus the content of branched polycarbonate. FIG. 3 illustrates that the melt viscosity of a composition including a medium molecular weight polycarbonate resin (PC B) with 10 wt% RDP can be reduced by replacing the polycarbonate with a lower molecular weight polycarbonate (PC A). Branched polycarbonate resin (PC G) was added to the formulation to increase melt strength, but as shown in FIG. 3, this was at the expense of increased viscosity. PC G has a weight average molecular weight of 33600 Daltons with a higher melt volume rate (MVR) of 2.5 cc/lO min (300° C., 2.16 kg).

Example 1.

[0087] The compositions described herein in Examples 1-5 were prepared by a twin-screw extruder. Various polycarbonate resins, phosphate-based flame retardants (RDP, BPADP, SOL- DP), phosphite heat stabilizers (e.g. TBPP), and parting agents/mold release agent such as pentaerythritol stearate were used to manufacture these compositions. In order to achieve a glass transition of 100 °C, 10 wt% RDP or 12 wt% SOLDP or 13/14 wt% BPADP was used in the polycarbonate-based resin formulations. Table 2 gives an overview of the materials used. Table 3 gives a list of techniques used to measure properties in the Examples.

[0089] Table 3. Test methods or standards used for measurement of properties.

[0090] The compositions were used to manufacture LTD tapes using the HPFIT™ impregnation technology. The extruder throughput and line speed was adjusted to control the thickness of the polymer film extruded to achieve the desired final Fiber Volume Fraction (FVF) in the UD Tape. The extrusion temperature (melt pipe) and die temperature were adjusted to enable the production of a polymeric film with consistent dimensions in function of time and line speed.

The UD tapes were manufactured by using a commercial continuous carbon fiber supplied by Toho Tenax, HTS45-E23 12K (70 tows).

[0091] The FVF was calculated from the weight of burn-off, wherein the polymer was burned to expose the fiber. A meter-long piece of tape was measured out, and the weight of the tape was taken. The tape was burned (to combust the polymer) under nitrogen atmosphere at 650 degrees Celsius for 45 minutes, and the remaining material (the fibers and FR char) were weighed.

When FRPC resin is used as a matrix in CF-FRPC UD tape, after a burn off test next to the carbon a residue will be left due to the FR component. This will lead to a higher fiber weight fraction and incorrect fiber weight fraction calculation. To properly calculate the fiber weight, fraction a correction needs to be applied. To do so, first the weight fraction of the FR residue (wf (fr res)) after bum-off is measured on the resin only 650 oC for 45 min under nitrogen flow, given by:

The fiber weight content ( fwf ) of FRPC UD tape should be calculated as follows:

with w sample^afterf e weight off the sample after burn off and w sample^ before ύo weight of the sample after burn-off The weight of the sample before and after is measured and thus known:

including (I) in (V) one can rewrite (V) to

{VI _?

Substituting (VI) in (II) gives the final weight fraction of fiber in FRPC tape correcting for the FR residue:

Then the weight fraction (fwf) was transformed to a volume fraction (fvf) using the density of each material (Fiber/Resin). The FVF is an average of twenty specimens across the width of the UD tape. Note: The density of used Toho Tenax, HTS45-E23 12K carbon fiber is 1.77 g/cc and density of used FRPC resins is 1.21 g/cc. Note that a calculated FVF can be determined as follows to verify results obtained by FVF burn-off method: dividing the areal weight of the sample by the areal weight of fiber (measured/consumed during production).

[0092] The melt strength of the polymeric film was visually assessed in the zone where the film exits the extrusion die until it hits the continuous fiber bed. A rating of 1, 3, or 9 was assigned, indicating insufficient, poor, or excellent melt strength, respectively. In the case of insufficient melt strength (rating 1), severe necking of the film occurs at the extrusion die upon drawing of the film. This causes film breakage and a highly unstable film resulting in poor quality UD tape. In the case of poor melt strength (rating 3), some degree of necking takes place and causes an instable film resulting in dry spots. This results in a non-robust process for manufacture UD tapes. In the case of excellent melt strength, limited necking of the film is observed and results in a stable film. In such situations the drawing speed (or line speed) can be achieved to increase the economics of the process while maintaining UD tape quality.

[0093] Desired properties of the UD tape included a tape thickness of 150 micrometers, a width of 120 millimeters (mm), an FVF of 50 to 60%, a T _g of 100 ± 5°C, fully impregnated fibers having a void content of 0%, and an efficient line speed (e.g., greater than or greater to 3.5 meters per minute (m/min)). Various UD tape manufacturing parameters that were monitored are shown in Table 4.

_

[0095] Table 5 illustrates polycarbonate compositions for CE 1-2 and Examples 1.1-1.4. FIGS. 4-6 illustrate photographs showing melt strength for CE#2, Example 1.2, and Example 1.3, respectively, showing unidirectional fiber layer 210 and extruded polycarbonate film 220. CE #2 had full coverage of fiber bed, very low necking, no film breakage, very stable film, die temperature 270-275°C, good impregnation, stable film up to 5 m/min. Example 1.2 didn’t cover the whole fiber bed, had a high amount of necking (asymmetrical), had little film breakage, with an unstable film, and die temperature needed to be reduce to 235°C (film still unstable), with good impregnation, and maximum line speed of 3 m/min. Example 1.3 had full coverage of fiber bed, some necking, slightly asymmetrical, no film breakage, good film stability, die temperature 235-240°C, good impregnation, line speed up to 4 m/min, with too much necking at line speeds above 4 m/min.

[0096] Table 5 illustrates polycarbonate compositions for CE 1-2 and Examples 1.1- .4.

* Comparative Example [0097] For UD Tape characteristics, all are averages of measured values by averaging 20 specimens taken across the width of the tape. For thickness, each specimen was measured three times. The areal weight is obtained by cutting a disk of from the tape to provide a sample having an area of 100 square centimeters. The disk is weighed. The areal weight is calculated from the weight divided by 100 cm ² _. The thickness is measured using a micrometer with a 6 mm diameter tip. Thickness is an average of twenty specimens across the width of the UD tape which was measured in triplicate per specimen. Tape is on specification when it meets all of the following conditions: 1] FVF is at least 50%: 2] Low porosity/dry fiber is not allowed (Impregnation rating 3 or more): 3] Tg should be 100 degrees C +/- 5; 4] The melt strength should be rated as 9 which is an indication of a stable melt film without necking or breaking up. 5] UD tape thickness should be within 0.1 and 0.15 mm range.

[0098] Standard deviation of the thickness, areal weight and FVF is based upon the dispersion of the respective datasets relative to its mean and is calculated as the square root of the variance.

[0099] The compositions CE#l and CE#2 have a low shear melt viscosity (measured at 300°C and 500 l/s) of respectively 84 and 158 Pascal seconds (Pa s) and result in good quality UD tapes when using the HPFIT™ technology. These resins have good melt strength and good impregnation characteristics (cf. FIG. 4). Unfortunately, these UD tapes have a glass transition temperature of l45°C whereas the target is 100 degrees Celsius. Therefore, experimental compositions including 10 wt% RDP were designed to accommodate this glass transition target (Examples 1.1; 1.2; 1.3; 1.4).

[00100] However, it was discovered that addition of 10 wt% RDP to a CE#2 base formulation resulted in insufficient melt strength (e.g., Example 1.1). Although the die/melt temperature was decreased from 270°C to 235°C (Example 1.2), the melt strength remained poor (see, FIG. 5). Due to this temperature reduction, the impregnation quality of the UD was compromised.

[00101] Surprisingly it was found that a combination of 10 wt% RDP addition and 10 wt% branched polycarbonate enabled the production of good quality UD tapes up to line speeds of 4 m/min (Example 1.3) (see, FIG. 6) at 235°C.

[00102] When a mold release was added (Example 1.4), it was found that the low shear melt viscosity was reduced through a lubricating effect. This was found to have a detrimental effect on the melt strength. Therefore, the line speeds had to be reduced to 3 m/min to enable the manufacturing of high quality UD tapes.

[00103] The balance in enhancing melt strength and reducing viscosity to enable line speeds above 4 m/min was not straightforward as exemplified in Table 6. Various ratios of

polycarbonate types and loadings of branched polycarbonate were explored, with temperature and line speed varied across each formulation, but did not yield any process or UD tape quality improvements.

[00104] Although Example 1.3 has good melt strength, the addition of branched polycarbonate is not the only factor affecting this. As demonstrated in Table 6, various formulation including 10 wt% RDP in combination with 5 or 10 wt% branched polycarbonate were evaluated.

Surprisingly, none of these provide sufficient melt strength for UD tape manufacturing at line speeds beyond 3.5 m/min. This indicates that an optimal combination of high and low molecular weight linear polycarbonate resins with branched polycarbonate resins can achieve good impregnation and good melt strength. In the case of Example 1.3, a combination of 10 wt% high molecular weight PC and 10 wt% branched PC along with 80 wt% medium viscosity PC and 10 wt% RDP resulted in a good balance.

Examples 2-3

[00105] Table 6 illustrates polycarbonate compositions for Examples 2.1-2.2 and 3.1-3.3.

[001061 Table 6. Polycarbonate compositions for Examples 2.1-2.2, and Examples 3.1-3.3.

* Comparative

Examples 4-5.

[00107] Other FR packages were evaluated such as 13/14 wt% BPADP and 12 wt% SOLDP as exemplified in Table 7, which shows the polycarbonate compositions for Examples 4.1-4.2 and Examples 5.1-5.4. FIG. 7 illustrates a photograph showing melt strength for Example 5.1, showing unidirectional fiber layer 210 and extruded polycarbonate film 220. Example 5.1 had full coverage of the fiber bed, some necking (slightly asymmetrical), no film breakage, good film stability, die temperature of 255 °C, good impregnation, no difference from addition of PETS, and line speed of up to 5 m/min. FIG. 8 illustrates a photograph showing melt strength for Example 5.4, showing unidirectional fiber layer 210 and extruded polycarbonate film 220.

[001081 Table 7. Polycarbonate compositions of examples 4.1-4.2 and Examples 5.1-5.3

* Comparative

[00109] Example 4.2, including 13% BPADP, also provided excellent melt strength. The combination of 10 wt% branched polycarbonate in combination with a low and medium MW polycarbonate resin provided good melt strength up to 4 m/min and at lower processing temperatures (235/240°C) which affected the viscosity and impregnation quality.

[00110] Examples 5.1 and 5.2, including 12 wt% SOLDP and 24% branched polycarbonate, were the most optimal formulation to provide a high quality LTD tape at line speeds up to 5 m/min.

[00111] Similar to Example 1.4, addition of PETS in Example 5.2 as mold release reduced the low shear melt viscosity compared to Example 5.1. This lubricating effect was desired to compensate for the increased viscosity of the higher content of branched polycarbonate in these formulations. [00112] Likewise, in Example 4.2, a combination of low and medium viscosity polycarbonate resin along with branched polycarbonate was evaluated. However, this did not lead to good processability. The film broke during production due to a lower melt strength in the low viscosity polycarbonate.

[00113] Fig. 9 shows an SEM of a cross section of Sample 5.4 showing excellent

impregnation of the fibers.

[00114] The terms and expressions that have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the embodiments of the present invention. Thus, it should be understood that although the present invention has been specifically disclosed by specific embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those of ordinary skill in the art, and that such modifications and variations are considered to be within the scope of embodiments of the present invention.

Exemplary Aspects.

[00115] The following exemplary aspects are provided, the numbering of which is not to be construed as designating levels of importance:

[00116] Aspect 1 provides a flame-retardant polycarbonate composition comprising: linear polycarbonate that is 20 wt% to 90 wt% of the polycarbonate composition; branched

polycarbonate that is 5 wt% to 30 wt% of the polycarbonate composition; and phosphorus- containing flame retardant that is 5 wt% to 20 wt% of the polycarbonate composition, preferably wherein composition is characterized by Vicat of 65°C to l30°C, more preferably 80 to 1 l5°C.

[00117] Aspect 2 provides the polycarbonate composition of Aspect 1, wherein the polycarbonate composition has a melt viscosity measured at 275°C and 500 l/s of less than 200 Pa s.

[00118] Aspect 3 provides the polycarbonate composition of any one of Aspects 1-2, wherein the polycarbonate composition has a melt viscosity measured at 275°C and 500 l/s of 100 Pa s to 199 Pa s.

[00119] Aspect 4 provides the polycarbonate composition of any one of Aspects 1-3, wherein the polycarbonate composition has a melt viscosity measured at 275°C and 500 l/s of 150 Pa s to 190 Pa s.

[00120] Aspect 5 provides the polycarbonate composition of any one of Aspects 1-4, wherein the polycarbonate composition has a T _g of 90 °C to 110 °C.

[00121] Aspect 6 provides the polycarbonate composition of any one of Aspects 1-5, wherein the polycarbonate composition has a T _g of 95 °C to 105 °C.

[00122] Aspect 7 provides the polycarbonate composition of any one of Aspects 1-6, wherein extrusion of the polycarbonate into a film having a thickness of 0.01 mm to 0.4 mm at an extrusion temperature of 230 °C to 280 °C results in substantially no necking of the film.

[00123] Aspect 8 provides the polycarbonate composition of any one of Aspects 1-7, wherein extrusion of the polycarbonate into a film having a thickness of 0.01 mm to 0.4 mm at an extrusion temperature of 230 °C to 280 °C results in substantially no breakage of the film.

[00124] Aspect 9 provides the polycarbonate composition of any one of Aspects 1-8, wherein the phosphorus-containing flame retardant is a phosphate-containing flame retardant or a phosphazene flame retardant.

[00125] Aspect 10 provides the polycarbonate composition of any one of Aspects 1-9, wherein the phosphorus-containing flame retardant is resorcinol bis(diphenyl phosphate) (RDP), bisphenol A bis(diphenyl phosphate) (BPADP), an oligomeric bisphosphate ester flame retardant, or a combination thereof.

[00126] Aspect 11 provides the polycarbonate composition of any one of Aspects 1-10, wherein the phosphorus-containing flame retardant is 9 wt% to 15 wt% of the polycarbonate composition.

[00127] Aspect 12 provides the polycarbonate composition of any one of Aspects 1-11, wherein the phosphorus-containing flame retardant is a phosphate-containing fire retardant that is 10 wt% to 14 wt% of the polycarbonate composition.

[00128] Aspect 13 provides the polycarbonate composition of any one of Aspects 1-12, further comprising secondary flame retardant.

[00129] Aspect 14 provides the polycarbonate composition of Aspect 13, wherein the secondary flame retardant is 0 wt% to 1 wt% of the polycarbonate composition.

[00130] Aspect 15 provides the polycarbonate composition of Aspect 13, wherein the secondary flame retardant is a perfluoroalkane sulfonate.

[00131] Aspect 16 provides the polycarbonate composition of Aspect 13, wherein the secondary flame retardant is potassium perfluorobutane sulfonate (Rimar salt).

[00132] Aspect 17 provides the polycarbonate composition of any one of Aspects 1-16, wherein the linear polycarbonate is 55 wt% to 85 wt% of the polycarbonate composition.

[00133] Aspect 18 provides the polycarbonate composition of any one of Aspects 1-17, wherein the linear polycarbonate is 60 wt% to 80 wt% of the polycarbonate composition.

[00134] Aspect 19 provides the polycarbonate composition of any one of Aspects 1-18, wherein the linear polycarbonate comprises a weight ratio of linear polycarbonate with a number average molecular weight of greater than or equal to 25,000 Daltons to linear polycarbonate with a number average molecular weight of less than 25,000 Daltons to less than 25,000 Daltons of 1 :5 to 1 : 10.

[00135] Aspect 20 provides the polycarbonate composition of any one of Aspects 1-19, wherein the linear polycarbonate comprises a weight ratio of linear polycarbonate with a number average molecular weight of greater than or equal to 25,000 Daltons to linear polycarbonate with a number average molecular weight of less than 25,000 Daltons to less than 25,000 Daltons of 1 :6 to 1 :8.

[00136] Aspect 21 provides the polycarbonate composition of any one of Aspects 1-20, wherein linear polycarbonate having a number average molecular weight of less than 25,000 Daltons is 0 wt% to 90 wt% of the polycarbonate composition.

[00137] Aspect 22 provides the polycarbonate composition of any one of Aspects 1-21, wherein linear polycarbonate having a number average molecular weight of less than 25,000 Daltons is 60 wt% to 80 wt% of the polycarbonate composition.

[00138] Aspect 23 provides the polycarbonate composition of any one of Aspects 1-22, wherein linear polycarbonate having a number average molecular weight of greater than or equal to 25,000 Daltons is 0 wt% to 90 wt% of the polycarbonate composition.

[00139] Aspect 24 provides the polycarbonate composition of any one of Aspects 1-23, wherein linear polycarbonate having a number average molecular weight of greater than or equal to 25,000 Daltons is 8 wt% to 10 wt% of the polycarbonate composition.

[00140] Aspect 25 provides the polycarbonate composition of any one of Aspects 1-24, wherein the branched polycarbonate is 8 wt% to 28 wt% of the polycarbonate composition.

[00141] Aspect 26 provides the polycarbonate composition of any one of Aspects 1-25, wherein the branched polycarbonate is 10 wt% to 24 wt% of the polycarbonate composition.

[00142] Aspect 27 provides the polycarbonate composition of any one of Aspects 1-26, further comprising a mold release agent.

[00143] Aspect 28 provides the polycarbonate composition of Aspect 27, wherein the mold release agent is 0 wt% to 5 wt% of the polycarbonate composition.

[00144] Aspect 29 provides the polycarbonate composition of Aspect 27, wherein the mold release agent is pentaerythritol stearate (PETS).

[00145] Aspect 30 provides the polycarbonate composition of any one of Aspects 1-29, further comprising a thermal stabilizer.

[00146] Aspect 31 provides the polycarbonate composition of Aspect 30, wherein the thermal stabilizer is 0 wt% to 0.2 wt% of the polycarbonate composition.

[00147] Aspect 32 provides the polycarbonate composition of Aspect 30, wherein the thermal stabilizer is a phosphite-containing thermal stabilizer. [00148] Aspect 33 provides the polycarbonate composition of Aspect 30, wherein the thermal stabilizer is tris(di-t-butylphenyl)phosphite (TBPP).

[00149] Aspect 34 provides the polycarbonate composition of any one of Aspects 1-33, wherein the linear polycarbonate, branched polycarbonate, phosphorus-containing flame retardant, optional secondary flame retardant, optional mold release agent, and optional thermal stabilizer, are 100 wt% of the polycarbonate composition.

[00150] Aspect 35 provides the polycarbonate composition of any one of Aspects 1-34 where the flame-retardant polycarbonate composition is free of fillers.

[00151] Aspect 36 provides the polycarbonate composition of any one of Aspects 1-34 where the flame-retardant polycarbonate composition is substantially free of fillers.

[00152] Aspect 37 provides the polycarbonate composition of any one of Aspects 1-34 comprising no more than 1 wt%, preferably no more than 0.75 wt%, more preferably no more than 0.5 wt% of fillers based on total weight of the polycarbonate composition.

[00153] Aspect 38 provides the polycarbonate of any one of Aspects 35-37 where the fillers are selected from the group consisting of mineral fillers (e.g. clay), talc, glass fibers, carbon fibers.

[00154] Aspect 39 provides the polycarbonate composition of any one of Aspects 1-34 where the composition comprises no more than 1 wt%, preferably no more than 0.75 wt%, and more preferably no more than 0.5 wt% of talc, clay, and glass fibers, based on total weight of the flame-retardant polycarbonate composition.

[00155] Aspect 40 provides the polycarbonate composition of any one of Aspects 1-39 where the weight ratio of phosphorous-containing flame retardant to branched polycarbonate is 0.3 to 1, preferably 0.4 to 0.1, more preferably 0.4 to 0.7.

[00156] Aspect 41 provides a fire-retardant polycarbonate fiber composite comprising the polycarbonate composition of any one of Aspects 1-40 comprising at least one layer of fibers therein.

[00157] Aspect 42 provides the polycarbonate fiber composite of claim 41, wherein the polycarbonate composition is a matrix that encapsulates the at least one layer of fibers.

[00158] Aspect 43 provides the polycarbonate fiber composite of any one of Aspects 41-42, wherein the fibers comprise glass fibers, carbon fibers, ceramic fibers, aramid fibers, polymeric fibers, basalt fibers, natural fibers, metallic fibers, or a combination thereof.

[00159] Aspect 44 provides the polycarbonate fiber composite of any one of Aspects 41-43, wherein the fibers comprise carbon fibers.

[00160] Aspect 45 provides the polycarbonate fiber composite of any one of Aspects 41-44, wherein the fibers are aligned in the same direction. [00161] Aspect 46 provides the polycarbonate fiber composite of any one of Aspects 41-45, wherein the polycarbonate fiber composite has a fiber volume fraction of 1% to 99%.

[00162] Aspect 47 provides the polycarbonate fiber composite of any one of Aspects 41-46, wherein the polycarbonate fiber composite has a volume fraction of the polycarbonate composition of 1% to 99%.

[00163] Aspect 48 provides the polycarbonate fiber composite of any one of Aspects 41-47, wherein the polycarbonate fiber composite has a thickness of 25 micrometers to 2 mm, preferably 50 micrometers to 2 mm, or more preferably 50 micrometers to 400 micrometers.

[00164] Aspect 49 provides the polycarbonate fiber composite of any one of Aspects 41-48 wherein the composite has an areal weight of 100 to 500, preferably 130 to 400, more preferably 140 to 200 g/m ² .

[00165] Aspect 50 the provides the polycarbonate fiber composite of any one of Aspects 41- 49 wherein the coefficient of variability of areal weight is less than 2%, preferably less than 1%.

[00166] Aspect 51 provides the polycarbonate fiber composite of any one of aspects 41-50 having a fiber volume fraction of 40-70% based on total volume of the composite.

[00167] Aspect 52 provides the polycarbonate fiber composite of any one of Aspects 41-51 having a coefficient of variability of fiber volume fraction of less than 6%, preferably less than 5.5%.

[00168] Aspect 52 provides the polycarbonate fiber composite of any one of Aspects 41-48, wherein the fiber composite is a flame-retardant unidirectional (UD) polycarbonate fiber composite tape, wherein the fibers of the at least one layer of fibers are oriented in the same direction.

[00169] Aspect 53 provides the UD tape of Aspect 52, wherein the tape has a thickness of 25 micrometers to 2 mm.

[00170] Aspect 54 provides the UD tape of any one of Aspects 52-53, wherein the tape has a thickness of 50 micrometers to 200 micrometers.

[00171] Aspect 55 provides the UD tape of any one of Aspects 52-54, wherein the tape has a width of 1 mm to 2,000 mm.

[00172] Aspect 56 provides the UD tape of any one of Aspects 52-55, wherein the tape has a width of 50 mm to 800 mm.

[00173] Aspect 57 provides the UD tape of any one of Aspects 52-56, wherein the UD tape has a fiber volume fraction of 40% to 70%.

[00174] Aspect 58 provides the UD tape of any one of Aspects 52-57, wherein the UD tape has a fiber volume fraction of 50% to 60%.

[00175] Aspect 59 provides the UD tape of any one of Aspects 52-58, wherein the UD tape has a volume fraction of the polycarbonate composition of 30% to 60%.

[00176] Aspect 60 provides the UD tape of any one of Aspects 52-59, wherein the UD tape has a volume fraction of the polycarbonate composition of 40% to 50%.

[00177] Aspect 61 provides the UD tape of any one of Aspects 52-60, wherein the UD tape has a void fraction of 0% to 5%.

[00178] Aspect 62 provides the UD tape of any one of Aspects 52-61, wherein the UD tape has a void fraction of less than 1%.

[00179] Aspect 63 provides a method of forming a fiber composite, the method comprising: combining the flame-retardant polycarbonate composition of any one of Aspects 1-40 with at least one layer of fibers to form the fiber composite comprising the polycarbonate composition, the polycarbonate composition comprising the at least one layer of fibers therein.

[00180] Aspect 64 provides the method of Aspect 63, wherein the method comprises solvent impregnation, aqueous slurry, film stacking, powder scattering, direct melt impregnation, or a combination thereof.

[00181] Aspect 65 provides the method of any one of Aspects 64-65, wherein the method comprises: extruding a hot melt film comprising the flame-retardant polycarbonate composition of any one of Aspects 1-40; and, contacting the hot melt film with at least one layer of fibers, to form the fiber composite comprising the polycarbonate composition, the polycarbonate composition comprising the at least one layer of fibers therein.

[00182] Aspect 66 provides the method of Aspect 65, wherein during the extrusion, an extrusion temperature of 230 °C to 280 °C is used.

[00183] Aspect 67 provides the method of any one of Aspects 65-66, wherein the method comprises forming the fiber composite at a speed of at least 2 m/min.

[00184] Aspect 68 provides the method of any one of Aspects 65-67, wherein the method comprises forming the fiber composite at a speed of 3.5 m/min to 10 m/min.

[00185] Aspect 69 provides the method of any one of Aspects 65-68, wherein the extruded film has a thickness of 0.01 mm to 1 mm.

[00186] Aspect 70 provides the method of any one of Aspects 65-69, wherein the extruded film has a thickness of 0.025 mm to 0.1 mm.

[00187] Aspect 71 provides the method of any one of Aspects 65-70, wherein the extruded film has a width of 1 mm to 2,000 mm.

[00188] Aspect 72 provides the method of any one of Aspects 65-71, wherein the extruded film has a width of 70 mm to 200 mm.

[00189] Aspect 73 provides the method of any one of Aspects 65-72, wherein the method is a method of forming UD tape, wherein the fibers of the at least one layer of fibers are aligned in the same direction.

[00190] Aspect 74 provides the method of any one of Aspects 65-73, wherein during the extrusion the film is free of necking and breakage.

[00191] Aspect 75 provides the method of any one of Aspects 65-74 where wherein during the contacting, speed of the at least one layer of fibers is at least 1.5 times, preferably at least two times speed of the hot melt film.

[00192] Aspect 76 provides the method of claim 75 where the extruding is from a linear die having an opening height of 0.1 mm the speed melt film is 0.5 to 0.6 times the speed of the at least one layer of fibers.

[00193] Aspect 77 provides the method of claim 75 where the extruding is from a linear die having an opening height of 0.2 mm and the speed of the melt film is 0.2 to 0.3 times the speed of the at least one layer of fibers.

[00194] Aspect 78 provides the method of claim 75 where the extruding is from a linear die having an opening height of 0.3 mm and the speed of the melt film is 0.1 to 0.2 times the speed of the at least one layer of fibers.

[00195] Aspect 79 provides the polycarbonate composition, fiber composite, or method of any one or any combination of Aspects 1-78 optionally configured such that all elements or options recited are available to use or select from.