A composite product and uses thereof

FIELD

[0001] The present invention relates to composite products, and more particularly to plastic composite products having flame retarding properties.

BACKGROUND

[0002] Flame retardant plastics have been in markets as long as plastics have been available. Modem polyolefin materials, such as polypropylene or polyethylene, belong to the most used segment of plastic materials and they tend to bum well instead.

[0003] Commonly plastics may be compounded with additives that bring flame retardant properties to the plastic material. Common methods to determine bum behaviour or flame retardant properties include the so-called UL94 test, which is a standardized procedure of horizontal and vertical burning, and the glow wire test.

[0004] It is also known to prepare plastic composite products incorporating natural fibres, such as wood fibres. However, wood fibres exhibit a poor flame resistance.

[0005] The present invention aims at overcoming at least part of the disadvantages in the known plastic products.

SUMMARY OF THE INVENTION

[0006] The invention is defined by the features of the independent claims. Some specific embodiments are defined in the dependent claims.

[0007] According to a first aspect of the present invention, there is provided a composite product comprising: a thermoplastic polymeric material; an organic fibrous material; and a flame retardant, wherein the composite product is capable of being melt processed in a temperature below 250 °C, such as below 210 °C, preferably below 190 °C. [0008] According to a second aspect of the present invention, there is provided a composite product comprising: a thermoplastic polymeric material; an organic fibrous material; and a flame retardant, wherein the composite product is capable of being melt processed in conditions where the organic fibrous material, particularly the fibres therein, remains substantially intact, typically such that the mechanical properties of the fibres do not become substantially deteriorated.

[0009] According to a third aspect of the present invention, there is provided use of the composite product according to the first aspect in the manufacturing of a three- dimensional article by a melt-processing method, such as extrusion or injection moulding.

[0010] According to a fourth aspect of the present invention, there is provided use of the composite product according to the first aspect or the second aspect in the manufacturing of an automotive industry component, a consumer electronic component, a building industry component, or furniture, or a part thereof.

[0011] According to a fifth aspect of the present invention, there is provided use of wood pulp in combination with a flame retardant as additives in a plastic product for improving flame resistance of the plastic product.

[0012] Various embodiments of the first, second, third, fourth or fifth aspect may comprise one or more features from the following bulleted list:

• Said melt processing comprises injection moulding or extrusion.

• The composite product is capable of being melt processed in conditions where the organic fibrous material, particularly the fibres therein, remains substantially intact, typically such that the mechanical properties of the fibres do not become substantially deteriorated.

• The composite product is capable of being melt processed in conditions where the fibres in the organic fibrous material do not become substantially shortened or chemically decomposed.

• The composite product is capable of being melt processed in conditions where the mechanical properties of the fibres do not become substantially deteriorated.

• The composite product is capable of being melt processed in a temperature below 250 °C, such as below 210 °C, preferably below 190 °C. • The composite product is capable of being melt processed in a temperature below 250 °C.

• The thermoplastic polymeric material is above its glass transition temperature, particularly in the case of amorphous polymers.

• The composite product comprises at least 30 wt-%, such as at least 50 wt-%, for example at least 70 wt-% of thermoplastic polymeric material, of total dry matter.

• The composite product comprises a recycled thermoplastic polymeric material, for example at least 50 wt-% of a recycled thermoplastic polymeric material, of total dry matter.

• The composite product comprises at least 20 wt-% of a recycled thermoplastic polymeric material, of total dry matter.

• The thermoplastic polymeric material comprises a polyolefin, such as polyethylene or polypropylene, preferably polypropylene.

• The thermoplastic polymeric material consists of a polyolefin or polyolefins.

• The thermoplastic polymeric material comprises a recycled thermoplastic polymeric material, such as a recycled polyolefin.

• The thermoplastic polymeric material comprises or consists of an amorphous polymer, such as polycarbonate.

• The thermoplastic polymeric material comprises a mixture of recycled polypropylene and virgin polypropylene.

• The organic fibrous material, preferably a cellulosic fibrous material, is capable of reducing or preventing dripping of the thermoplastic polymeric material upon burning of the thermoplastic material.

• The organic fibrous material comprises a cellulosic or lignocellulosic fibrous material, such as a pulp, for example wood pulp or straw pulp.

• The composite product comprises a pulp as the organic fibrous material.

• The pulp originates from a wet pulping process.

• The cellulosic fibrous material comprises wood pulp, such as hardwood or softwood chemical or mechanical pulp, preferably bleached softwood chemical pulp, such as bleached pine chemical pulp.

• The amount of the cellulosic fibrous material is at least 5 wt-%, such as at least 10 wt-%, for example 20 to 70 wt-%, or 5 to 20 wt-%, calculated of the total dry matter of the composite product. • The flame retardant comprises aluminium polyphosphate.

• The flame retardant comprises a melamine-based flame retardant, such as melamineformaldehyde.

• The flame retardant comprises one or more of the following: aluminium polyphosphate, melamine, melamine formaldehyde, melamine cyanurate, or a mixture thereof.

• The amount of the flame retardant is at least 5 wt-%, such as at least 10 wt-%, for example at least 20 wt-%, calculated of the total dry matter of the composite product.

• The composite product comprises less than 5 wt-%, such as less than 2 wt-% of inorganic material, for example inorganic flame retardants, inorganic fibrous materials and inorganic fillers.

• The composite product is in the form of granulates or powder, preferably granulates with a substantially spherical or cylindrical shape, for example with a diameter in the range 1 to 5 mm, such as 2 to 4 mm.

• The composite product comprises: at least 30 wt-%, for example at least 60 wt-%, of a thermoplastic polymeric material; at least 5 wt-% of wood pulp; at least 5 wt-% of a flame retardant, calculated of the total dry matter of the composite product.

• The composite product comprises: at least 30 wt-% of a thermoplastic polymeric material; at least 10 wt-%, for example 10 to 60 wt-% of wood pulp; at least 10 wt- % of a flame retardant or flame retardants, calculated of the total dry matter of the composite product.

• The composite product is configured for use in a compounding process for manufacturing of an extruded three-dimensional composite article.

[0013] Advantages of the invention

[0014] The present invention provides many advantages.

[0015] The present product may provide cost savings compared to commercially available flame retarding products while still maintaining a sufficient or even equal performance.

[0016] Some embodiments may enable replacement of conventional flame retardants or at least a reduction in their amounts in plastic composite products and articles. [0017] The present invention may provide improved material sustainability by enabling efficient utilization of recycled materials and/or materials from renewable sources.

[0018] The present invention may enable use of recycled plastic materials, which advantageously reduces the carbon footprint of the product.

[0019] The present invention may avoid or reduce use of virgin materials.

[0020] The present products may be applicable in automotive, consumer electronics and building industries.

[0021] In some embodiments, the product may have a high notched Charpy impact strength, particularly in low temperatures.

[0022] In some embodiments, the product may exhibit an improved impact resistance in low temperatures, such as below 0 °C.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIGURES 1 and 2 illustrate SEM micrographs of a sample in accordance with at least some embodiments of the present invention.

EMBODIMENTS

[0024] DEFINITIONS

[0025] In the present context, the term “flame retardant” comprises a substance that can be added to combustible materials to help to prevent or slow fires from spreading. Flame retardants are typically activated by the presence of an ignition source and are intended to prevent or slow the further development of ignition by a variety of different physical and chemical methods.

[0026] By “plastic material” or “plastic polymeric material” it is typically referred to thermoplastic materials and/or thermoset materials. Thermoplastic materials do not undergo any major chemical change in their composition when heated and thus can be moulded repeatedly. Thermoset materials can melt and take shape only once: after they have solidified, they stay solid. If reheated, thermoset materials decompose rather than melt. In the thermosetting process, an irreversible chemical reaction occurs.

[0027] A plastic material may comprise, in addition to the essential polymers themselves, also various additives. Such additives (polymer additives) typically improve processability and/or usability of the plastic material.

[0028] In the present context, any reference to a thermoplastic polymer or a thermoplastic polymeric material may cover a mixture of a thermoplastic polymer and one or more polymer additives, such as antioxidants, plasticisers, lubricants, fillers, extenders, stabilisers, process aids, impact modifiers and mixtures thereof.

[0029] In the present context, the term “recycled plastics” comprises or consists of post-consumer recycled plastics or pre-consumer recycled plastics or a mixture thereof, preferably the term “recycled plastics” substantially consists of post-consumer recycled plastics.

[0030] In the present context, the term “pre-consumer recycling” refers to recycling of waste materials that were created during the process of manufacturing or delivering goods prior to their delivery to a consumer.

[0031] In the present context, the term “post-consumer recycling” refers to recycling of waste materials that have already passed through to the consumer.

[0032] In the present context, the term “biodegradability” refers to ability to decay naturally and in a way that is not harmful to the environment.

[0033] In the present invention it has been surprisingly observed that by incorporating both organic fibrous material and a flame retardant to a plastic matrix, typically in the form of additives, it may be possible to provide plastic products or plastic composite products with improved properties.

[0034] Advantageously, the present products, which comprise an organic fibrous material, may prevent dripping of burning plastic particles, which dripping is a typical phenomenon when a plastic material bums.

[0035] In preferred embodiments, the present compositions and products comprise a mixture of pulp, such as wood pulp and a thermoplastic polymeric material. [0036] The present composite product is typically intended to serve as a starting material for manufacturing of solid composite articles by various shaping and/or meltprocessing methods, such as extrusion or injection moulding.

[0037] In an embodiment, the composite product may be used, typically as a starting material, in the manufacturing of solid composite articles, typically three-dimensional solid composite articles, by injection moulding.

[0038] Plastic material

[0039] In one embodiment, the product comprises a thermoplastic polymeric material, such as a recycled thermoplastic polymeric material. The thermoplastic polymeric material may be selected from the following group: polyolefin, such as polyethylene and/or polypropylene, preferably polypropylene, such as recycled polypropylene.

[0040] An advantage of using polyolefins, for example in comparison to acrylonitrile butadiene styrene (ABS), is that the cycle time during injection moulding may be shorter, and the melt processing temperature, typically during infeed into a mould, may be lower, for example lower by about 50 °C. Further, the moulded composite product may solidify already in a higher temperature, whereby the solidified product can be removed from the mould.

[0041] The polyolefin may be a recycled polyolefin, for example a mixture comprising different recycled polypropylenes with a broad molar mass range.

[0042] Typically, recycled thermoplastic polymeric materials, such as recycled polypropylene, comprise plastic materials originating from various sources and possibly manufactured by various techniques.

[0043] Typically, recycled plastic materials (the polymer chains) tend to decompose faster than virgin plastic materials upon burning because the recycled plastic materials have already undergone several heating cycles during their lifetime. While plastic materials are conventionally protected by incorporating antioxidants and other stabilizers, such additives however become slowly consumed during the processing cycles, which makes recycled plastic materials less flame resistant. At least some embodiments of the present invention may improve flame resistance of composites comprising recycled plastics.

[0044] The present invention provides a composite product comprising a thermoplastic polymeric material; an organic fibrous material; and a flame retardant. Typically the composite product is capable of being melt processed, for example by injection moulding or by extrusion, in a temperature below 250 °C, such as below 210 °C, preferably below 190 °C. The thermoplastic polymeric material is preferably above its glass transition temperature.

[0045] In some embodiments, there is provided a composite product comprising: a thermoplastic polymeric material; an organic fibrous material; and a flame retardant, wherein the composite product is capable of being melt processed in conditions where the organic fibrous material, particularly the fibres therein, remains substantially intact, typically such that the mechanical properties of the fibres do not become substantially deteriorated.

[0046] Preferably, the composite product is capable of being melt processed in conditions where the fibres in the organic fibrous material do not become substantially shortened or chemically decomposed.

[0047] Typically, the composite product is extrudable or injectable in elevated temperatures, such as in 180 to 250 °C, for example 180 to 210 °C. The thermoplastic polymeric material is preferably above its glass transition temperature.

[0048] Advantageously, when manufacturing a composite article from the present composite product, the melt processing temperature of the composite product is maintained so low that the cellulosic fibres do not become damaged or burned in the process. Also in other respects the composite article manufacturing process, such as an extrusion process or an injection moulding process, shall be sufficiently gentle in order not to damage the fibres.

[0049] Conditions which may lead to damage of organic fibres, such as cellulosic fibres, may include high temperatures, such as above 250 °C, high pressure, high humidity, high shear forces, or any combinations thereof.

[0050] In one embodiment, the melt flow index of the thermoplastic polymer, such as recycled thermoplastic polymer, is less than 80 g / 10 min, such as 10 to 50 g / 10 min.

[0051] In one embodiment, the melt flow index of the thermoplastic polymeric material, such as recycled thermoplastic polymeric material, is at least 2 g / 10 min, for example at least 5 g / 10 min, for example at least 10 g / 10 min.

[0052] In some embodiments, the composition comprises at least two thermoplastic polymeric materials, such as a recycled thermoplastic polymeric material and a virgin thermoplastic polymeric material. If the melt flow index of one of the polymeric materials is low, it may be balanced by adding a second polymeric material with a higher melt flow index.

[0053] In one embodiment, the melt flow index of a first thermoplastic polymer, such as recycled thermoplastic polymer, is less than 80 g / 10 min, and the melt flow index of a second thermoplastic polymer, such as virgin thermoplastic polymer, is more than 150 g / 10 min.

[0054] A dispersive mixing is preferred when mixing the cellulosic fibres and the thermoplastic polymer, avoiding large shear rates.

[0055] In one embodiment, dispersive additives are added to the mixture in order to facilitate mixing of the thermoplastic polymer and the fibres.

[0056] Viscosity of the mixture is preferably suitably low so that efficient mixing of the polymer and the fibres is achieved.

[0057] Viscosity is preferably adjusted to be suitable for melt processing of the mixture.

[0058] In some embodiments, the product comprises post-consumer recycled plastic material, such as post-consumer recycled plastic packaging material.

[0059] The product may comprise pre-consumer recycled plastic material as well.

[0060] In one embodiment, the thermoplastic material comprises or consists of a biodegradable thermoplastic polymeric material.

[0061] Advantageously, in some embodiments it may be possible to include high amounts of recycled plastic material to the composite product, such as at least 20 wt-%, for example at least 50 wt-% for example at least 60 wt-% of total dry matter. The dripping phenomenon may be successfully prevented also in composite products comprising more than 50 wt-% recycled plastic material.

[0062] Organic fibrous material

[0063] In one embodiment, the product comprises an organic fibrous material, for example a biodegradable organic fibrous material. [0064] In a preferred embodiment, the product comprises a cellulosic or lignocellulosic fibrous material, most preferably a cellulosic fibrous material.

[0065] In one embodiment, the product comprises a pulp as the organic fibrous material, such as a wood pulp or a straw pulp. The pulp is preferably a wet pulp, typically originating from a wet pulping process.

[0066] In an embodiment, the pulp is obtained from a pulping process, such as a wood pulping process.

[0067] The pulping process may comprise chemical pulping, chemimechanical pulping, chemithermomechanical pulping, semichemical pulping and/or mechanical pulping.

[0068] The pulp, such as wood pulp, for example wet wood pulp, may be selected from the following group: chemical pulp, chemimechanical pulp, chemithermomechanical pulp, semichemical pulp, mechanical pulp, and any combinations thereof.

[0069] The wood pulp may be selected from the following group: chemical pulp, chemimechanical pulp, semimechanical pulp and mechanical pulp.

[0070] Chemical pulp may comprise sulphate pulp (also called as kraft pulp), sulphite pulp, organosolv pulp or any combination thereof.

[0071] Chemimechanical pulp or semichemical pulp may comprise chemimechanical pulp, i.e. CMP, chemirefiner mechanical pulp, i.e. CRMP, chemithermomechanical pulp, i.e. CTMP, high-temperature chemithermomechanical pulp, i.e. HT-CTMP, sulphite-modified thermomechanical pulp (SMTMP), reject CTMP, groundwood CTMP, semichemical pulp, i.e. SC, neutral sulphite, semi-chemical pulp (NSSC) or any combination thereof.

[0072] Mechanical pulp may comprise mechanical pulp, which may be produced, for example, by refining or by grinding. Examples of such pups include: refiner mechanical pulp, i.e. RMP, and pressurised refiner mechanical pulp, i.e. PRMP, pre-treatment refiner chemical alkaline peroxide mechanical pulp, i.e. P-RC APMP, thermomechanical pulp, i.e. TMP, thermomechanical chemical pulp, i.e. TMCP, high-temperature TMP, i.e. HT-TMP, RTS-TMP, alkaline peroxide pulp (APP), alkaline peroxide mechanical pulp (APMP), alkaline peroxide thermomechanical pulp (APTMP), thermopulp, groundwood pulp (groundwood pulp, i.e. GW, or stone groundwood, i.e. SGW), pressurised groundwood pulp, i.e. PGW, as well as super pressure groundwood pulp, i.e. PGW-S, thermo groundwood pulp, i.e. TGW, or thermo stone groundwood pulp, i.e. TSGW.

[0073] The pulp may comprise hardwood pulp or softwood pulp or a mixture thereof.

[0074] In one embodiment, the pulp may be made from any broad-leaved tree such as a tree from the betulaceae family, for example birch or aspen, from the salicaceae family, from eucalyptus, mixed tropical hardwood or pines or from any combination of the aforementioned. The pulp may be also made from any conifer such as spruce or pine or from any combination thereof. The pulp may be also made from a combination of broad-leaved trees and conifers.

[0075] Particularly advantageous pulps include hardwood and softwood chemical pulps and CTMP and TMP.

[0076] The pulp may be bleached or unbleached.

[0077] In one embodiment, the pulp comprises or consists of chemical pulp, such as bleached or unbleached kraft pulp, which is prepared by a kraft process that involves at least the following steps: cooking (delignification), oxygen delignification, and optionally bleaching.

[0078] In one embodiment, the pulp comprises or consists of wet pulp, i.e. never-dried pulp.

[0079] By means of including cellulosic fibres in the composite product it may be possible to keep the total amount of flame retarding substances below 40 wt-%, for example below 30 wt-%, such as below 20 wt-%.

[0080] In some embodiments, the pulp fibres, typically from a wet pulping process, produce a three-dimensional fibre network structure, which provides desirable mechanically isotropic properties for the composite product as well as inhibits dripping of burning plastic particles.

[0081] An advantage of cellulosic fibres from a wet pulping process is that they may produce a three-dimensional fibre network structure, which preferably provide isotropic properties. [0082] Additionally, it is believed that cellulosic fibres do not become as easily oriented in a flow of plastic material as for example fibreglass fibres.

[0083] The organic fibrous material, such as pulp, may comprise recycled fibres or virgin fibres or a mixture thereof.

[0084] An advantage obtained via the presence of organic fibres is that shrinkage of the product, particularly in a cross-wise direction with regard to the direction of flow in moulding, may be more easily controlled, particularly when comparing to composites comprising glass fibres.

[0085] In one embodiment, the shrinkage of the composite product is in the range 1.0 to 2.0%, both cross-wise and length-wise with regard to the direction of flow in moulding, in the moulding process.

[0086] Flame retardants

[0087] The product may further comprise a flame retardant.

[0088] In the present context, the term “flame retardant” may refer to a single flame retarding substance or, preferably, to a combination of several flame retarding substances. Thus, the product may comprise one or more flame retarding substances, for example at least 1, for example at least 2, such as 1 to 5, such as 2 to 4 flame retarding substances.

[0089] The flame retardant may comprise a reactive flame retardant or an additive flame retardant.

[0090] The flame retardant may be selected from various types of flame retardants, for example minerals, organohalogen compounds, organophosphorus compounds, inorganic phosphorus compounds, and organic compounds, and combinations thereof.

[0091] In some embodiments, the flame retardant comprises an intumescent flame retardants.

[0092] In some embodiments, the flame retardant comprises a char forming substance, such as penta-erythritol (PER). [0093] Examples of mineral flame retardants include: aluminium trihydroxide (ATH), magnesium hydroxide (MDH), huntite and hydromagnesite, various hydrates, red phosphorus, and boron compounds, mostly borates.

[0094] Examples of organohalogen flame retardants include: organochlorines such as chlorendic acid derivatives and chlorinated paraffins; organobromines such as decabromodiphenyl ether (decaBDE), decabromodiphenyl ethane (a replacement for decaBDE), polymeric brominated compounds such as brominated polystyrenes, brominated carbonate oligomers (BCOs), brominated epoxy oligomers (BEOs), tetrabromophthalic anyhydride, tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCD).

[0095] Examples of organophosphorus flame retardants include: organophosphates such as triphenyl phosphate (TPP), resorcinol bis(diphenylphosphate) (RDP), bisphenol A diphenyl phosphate (BADP), and tricresyl phosphate (TCP); phosphonates such as dimethyl methylphosphonate (DMMP); and phosphinates such as aluminium diethyl phosphinate. In one embodiment, the flame retardant comprises both phosphorus and a halogen, for example tris(2,3-dibromopropyl) phosphate (brominated tris) and chlorinated organophosphates such as tris(l,3-dichloro-2-propyl)phosphate (chlorinated tris or TDCPP) and tetrakis(2- chlorethyl)dichloroisopentyldiphosphate (V6).

[0096] Examples of inorganic phosphorus flame retardants include aluminium polyphosphate (APP) and melamine polyphosphate (MPP).

[0097] Examples of organic flame retardants include carboxylic acid and dicarboxylic acids.

[0098] In one embodiment, the flame retardant comprises an inorganic phosphorus flame retardant, preferably aluminium polyphosphate (APP).

[0099] In one embodiment, the flame retardant comprises a mineral flame retardant, preferably aluminium trihydroxide (ATH).

[00100] In one embodiment, the flame retardant comprises pentaerythritol (PER).

[00101] In one embodiment, the flame retardant comprises or consists of a melamine based flame retardant, such as melamine, melamine resin, such as melamine formaldehyde resin or melamine urea formaldehyde resin, melamine cyanurate, or any mixture thereof. [00102] For example, the flame retardant may consist of a mixture of melamine and melamine formaldehyde.

[00103] In some embodiments, the flame retardant comprises or consists of a combination of APP and one or more melamine-based flame retardants. For example, the flame retardant may consist of a mixture of APP and melamine, or a mixture of APP and melamine formaldehyde, or a mixture of APP and melamine cyanurate.

[00104] In some embodiments, the flame retardant comprises or consists of a combination of APP and PER.

[00105] In some embodiments, the flame retardant comprises or consists of a combination of APP, PER and a melamine based flame retardant, preferably melamine, melamine cyanurate or melamine formaldehyde.

[00106] In some embodiments, it may be possible to entirely dispense with PER.

[00107] The flame retardant typically has an average (weight) particle size of less than

20 pm, such as less than 10 pm, for example 1 to 20 pm, for example 1 to 10 pm, for example to facilitate mixing and adjustment or development of viscosity.

[00108] Shear thinning of the composite product may improve as a result of incorporating suitable flame retardants, possibly via a lubricating mechanism. This is important particularly during melt processing, such as extrusion or injection moulding. Advantageously it is possible in this way to compensate the opposite effect to the shear thinning caused by presence of organic fibres in the composite product.

[00109] Advantageously, the ratio the amount of APP to the amount of the other flame retardants is in the range 1:1 to 5:1 (wt/wt), such as 2:1 to 4:1 (wt/wt), for example about 3:1 (wt/wt).

[00110] Advantageously, the ratio APP/melamine based flame retardant is in the range 1 :1 to 10:1 (wt/wt), for example 2:1 to 6:1 (wt/wt).

[00111] Advantageously, the ratio APP/melamine cyanurate is in the range 1 :1 to 3:1 (wt/wt), for example about 2:1 (wt/wt).

[00112] The cellulosic fibres and the flame retar dant(s) may function as nucleating agents and also increase late-stage crystallization degree of the polymer. Advantageously, the cellulosic fibres and the flame retardant(s) may lead to formation of moderately small bunches of polymer crystals and simultaneously to the presence of sufficient amorphous polymeric material that is able to prevent disintegration of the composite structure.

[00113] The product may comprise further additives, for example plastomers and/or elastomers, which may improve processability, elasticity and/or mechanical properties of the product.

[00114] In one embodiment, the product comprises a compatibilizer that is capable of increasing interaction between the cellulosic fibres and the thermoplastic polymeric material.

[00115] The compatibilizer may be an elastomer or an plastomer.

[00116] Typically, the compatibilizer is an elastomer or plastomer that is capable of interacting with the cellulosic fibres via non-covalent interactions, for example van der Waals interactions and/or hydrogen bonding. Preferably the elastomer is capable of providing flexibility and improved mechanical properties.

[00117] Suitable compatibilizers include for example maleic acid grafted ethylene propylene diene monomer (EPDM-MAH), ethylene propylene diene monomer (EPDM), PP- MAH and EPDM-PP.

[00118] In one embodiment, the compatibilizer comprises EPDM-MAH and/or PP- MAH.

[00119] In one embodiment, the compatibilizer comprises EPDM.

[00120] In one embodiment, the compatibilizer comprises PP-MAH.

[00121] In one embodiment, the compatibilizer comprises EPDM-PP.

[00122] An advantage of MAH-based compatibilizers is the increased reaction rate.

[00123] The composite product may comprise at least 1 wt-%, such as 1 to 3 wt-%, of a compatibilizer, calculated from total dry matter of the composite product.

[00124] In one embodiment, the product comprises a plastomer, such as a polyolefin plastomer, for example Queo™. An advantage is that impact resistance of the product may be increased. [00125] The compatibilizer may be in the form of a co-polymer, such as Queo, or a grafted polymer. An advantage is that the compatibilizer may then interact and better mix with different polymers. For example, Queo contains polypropylene which contains (as branches) polymer structures that are different from the structure of polypropylene.

[00126] In MAH-based compatibilizers, the MAH unit is typically grafted to a polymer, such as PP.

[00127] An advantage of various MAH-based compatibilizers is that they may improve wettability of the fibres and mixing with the polymer, particularly with polymers with a high melt flow index.

[00128] The MAH compounds may provide chemical coupling of the fibres and the polymers.

[00129] Compatibilizers may also be referred to as coupling agents, which typically enable mixing of different substances, such as polymers, with each other by mechanical and/or chemical interactions, for example via covalent and/or non-covalent interactions.

[00130] Possible functions of MAH-based substances, such as EPDM-MAH, are that they may increase impact strength, enable reactive and non-reactive mixing, increase flexibility, ability to couple and/or ability to mix.

[00131] In one embodiment, the MAH-based compatibilizer is SEBS-MAH.

[00132] In one embodiment, the compatibilizer comprises EB (ethylene butylene block co-polymer). EP may improve mixing and dispersion and/or impact strength.

[00133] In some embodiments it is provided a composite product in the form of a mixture in which the components of the mixture are compatible with each other and form a stabilized mixture with good dispersion. The dispersion preferably is maintained during later processing stages and during use of the product.

[00134] The composite product may comprise at least 5 wt-%, such as 5 to 25 wt-%, of a plastomer, calculated from total dry matter of the composite product.

[00135] In one embodiment, the product comprises a silane as a compatibilizer. The composite product may comprise at least 0.2 wt-%, such as at least 1 wt-%, such as 1 to 3 wt-%, of a silane, calculated from total dry matter of the composite product. [00136] In some embodiments, the product further comprises inorganic fillers, such as zeolite, talc, calcium carbonate or a mixture thereof, preferably zeolite. For example, the product may comprise at least 1 wt-%, such as 1 to 10 wt-% or 1 to 5 wt-% of an inorganic filler, calculated from total dry matter of the composite product.

[00137] An inorganic filler, such as zeolite, may reduce smoke formation and delay the onset of exothermic burning reactions.

[00138] An inorganic filler, such as zeolite, may chemically react with and/or act like a sponge and physically block or trap substances that are released during burning.

[00139] The composite product preferably has improved flame resistant and mechanical properties.

[00140] In one embodiment, the ignition time of the composite product is longer than 15 seconds in a glow wire test in a temperature of 750 °C.

[00141] The composite product according to some embodiments may be used in the manufacturing of three-dimensional articles, typically by extrusion or injection moulding techniques. It is then advantageous to provide the composite product in the form of substantially dry granulates. The composite product may be in the form of a concentrate, such as a pulp-rich concentrate, which may then be further diluted with a plastic material before the extrusion or injection moulding step.

[00142] In an embodiment, the composite product comprises: a thermoplastic polymeric material; an organic fibrous material; and a flame retardant, wherein the composite product is capable of being melt processed in a temperature below 250 °C, such as below 210 °C, preferably below 190 °C, and preferably said melt processing comprises injection moulding or extrusion. Typically the organic fibrous material is a cellulosic fibrous material, and is capable of reducing or preventing dripping of the thermoplastic polymeric material upon burning of the thermoplastic material. Further, the product preferably comprises a pulp as the organic fibrous material, the pulp originating from a wet pulping process. It is advantageous that the product comprises at least 5 wt-% flame retardant. It is further advantageous that the product comprises at least 20 wt-% of recycled plastic material.

[00143] Example 1 [00144] In the following examples, the plastic material may comprise or consist of recycled plastic material, and independently the cellulosic fibrous material may comprise or consist of wood pulp. These example are advantageous in the sense that horizontal burning property of the material is less than 8 cm per minute and that no dripping of burning plastic material takes place.

[00145] In one example the composite product comprises at least 75 wt-% plastic material, at least 10 wt-% cellulosic fibrous material, and at least 5 wt-% flame retardants, such as a mixture of APP and melamine formaldehyde, of total dry matter.

[00146] In one example the composite product comprises at least 75 wt-% plastic material, at least 15 wt-% cellulosic fibrous material, and at least 5 wt-% flame retardants, such as a mixture of APP and melamine formaldehyde, of total dry matter.

[00147] In one example the composite product comprises at least 75 wt-% plastic material, at least 10 wt-% cellulosic fibrous material, and at least 10 wt-% flame retardants, such as a mixture of APP and melamine formaldehyde, of total dry matter.

[00148] In one example the composite product comprises at least 80 wt-% plastic material, at least 10 wt-% cellulosic fibrous material, and at least 5 wt-% flame retardants, such as a mixture of APP and melamine formaldehyde, of total dry matter.

[00149] In one example the composite product comprises at least 80 wt-% recycled plastic material, at least 5 wt-% cellulosic fibrous material, and at least 10 wt-% flame retardants, such as a mixture of APP and melamine formaldehyde, of total dry matter.

[00150] In one example the composite product comprises 75 to 85 wt-% plastic materials, such as recycled PP, 10 to 15 wt-% cellulosic fibrous material, and 5 to 10 wt-% flame retardants, such as a mixture of APP and melamine formaldehyde, of total dry matter.

[00151] At least some of the above examples of the composite product may be used in the manufacturing of articles or components for public transport vehicles, such interior components or parts. In such applications it is typically required that horizontal burning property of the material is less than 8 cm per minute and that no dripping of burning plastic material takes place.

[00152] Example 2

[00153] In the following we describe experimental results for eight injection moulded samples (solid articles) with variable amounts of plastic material, cellulosic fibrous material and flame retardants and possibly additives. The additives may also possess flame retarding properties.

[00154] The sample compositions are given in Table 1 (Samples 1 to 8). Samples 1 and 2 are reference samples that do not contain any cellulosic fibres. Samples 3 to 7 comprise cellulosic fibres, plastic materials and flame retardants. Sample 8 is also a reference sample and does not comprise any cellulosic fibres.

[00155] Glow wire test

[00156] Flame retarding properties were tested by a glow wire test in which a glowing or heated wire was contacted with the sample for 30 seconds, and the ignition and eventual burning was monitored. The temperature of the wire was 650 °C or 750 °C. The results are shown in Table 2. The sample was considered to pass the test if there was no ignition or the ignition time was larger than 5 seconds, and if ignition occurred after 5 seconds, if the burning stopped within 30 seconds after removing contact with the glowing wire.

[00157] All samples 3 to 7 passed the 750 °C glow wire test: either the samples did not ignite at all or the ignition time was long, in the range 17 to 22 seconds, and the burning stopped within 30 seconds after removing contact with the glowing wire.

[00158] Dripping

[00159] It was observed that Samples 3 to 7 did not drip any burning plastic particles during burning.

[00160] By contrast, Samples 1, 2 and 8, which did not contain any cellulosic fibres, dripped burning particles during burning.

[00161] Mechanical properties

[00162] Impact tests according to ISO 179 standard were carried out on all Samples 1 to 8. The results are shown in Table 2.

[00163] In the impact test, the sample (a three-dimensional article) was considered to pass if the article remained intact despite subjecting the article to a mechanical impact. The sample was considered to fail if large cracks appeared or if parts of the article were removed as a result of the impact. The impact test was carried out in two temperatures, -15 °C and - 25 °C. All samples 3 to 7 passed the impact test in both temperatures. [00164] Additionally, mechanical properties were tested by determining Charpy impact strength of the samples, both in room temperature and in -30 °C.

[00165] Table 3 gives mechanical properties measured for Samples 6 and 3.

[00166] Table 1. Sample compositions.

VI B = master batch consisting of 70% wood pulp and 30% virgin PP

[00167] Table 2. Test results. [00168] Table 3. Mechanical properties.

[00169] FIGURES 1 and 2 illustrate SEM micrographs of composite articles in accordance with Sample 5. [00170] It can be observed that even upon breaking of the composite product, the cellulosic fibres do not become detached from the plastic matrix.

[00171] It is to be understood that the embodiments of the invention disclosed are not limited to the particular structures, process steps, or materials disclosed herein, but are extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.

[00172] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment.

[00173] As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. In addition, various embodiments and example of the present invention may be referred to herein along with alternatives for the various components thereof. It is understood that such embodiments, examples, and alternatives are not to be construed as de facto equivalents of one another, but are to be considered as separate and autonomous representations of the present invention.

[00174] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided, such as examples of lengths, widths, shapes, etc., to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

[00175] While the forgoing examples are illustrative of the principles of the present invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.

[00176] The verbs “to comprise” and “to include” are used in this document as open limitations that neither exclude nor require the existence of also un-recited features. The features recited in depending claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, it is to be understood that the use of “a” or “an”, i.e. a singular form, throughout this document does not exclude a plurality.

INDUSTRIAL APPLICABILITY

[00177] The present products may be applicable for example in automotive industry parts, consumer electronic parts, furniture, building industry components, electric industry components and equipment. Further, the present product may be used as a replacement for fibreglass reinforced plastic materials.

ACRONYMS LIST APP aluminium polyphosphate

PP polypropylene

PER pentaerythritol

EPDM ethylene propylene diene monomer rubber

EPDM-MAH maleic anhydride grafted ethylene propylene diene monomer EPDM-PP ethylene propylene diene modified polypropylene

PP-MAH maleic anhydride grafted polypropylene