Polyol composition., polyurethane reaction system and polyurethane product prepared therefrom

Technical Field

The present invention relates to a polyol composition, a polyurethane reaction system comprising the polyol composition, and use thereof in the preparation of polyurethane composites.

Background Technology

The polyol composition in a polyurethane reaction system is very important, and different polyol compositions may bring different physical properties and reaction products. Particularly when used for outdoor parts such as those for wind blades, ships and the like, it is important whether the polyol composition can satisfy physical properties required for producing a polyurethane product having a higher quality.

Prior art discloses a polyurethane-modified acrylate polymer with high branching degree and a resin composition prepared therefrom, e.g. the polyurethane modified acrylate polymer is prepared by adding dropwise an isocyanate in the presence of a polyol and a hydroxyl- containing acrylate to perform the polymerization and the end-capping simultaneously to obtain a prepolymer, and then performing the graft polymerization on the prepolymer and a branching agent. Also, an unsaturated hyperbranched polyurethane prepolymer, and a preparation process and use thereof is known, wherein hydroxyl-terminated small molecular polyol and diisocyanate are mixed and heated to 80°C to perform the reaction for 2-4 hours; after the reaction is finished, the temperature is reduced to 40°C, and a capping agent is added, the temperature is increased to 80°C to proceed the reaction for 3-5 hours, the temperature is reduced to 50°C to perform the discharging, thus the unsaturated hyperbranched polyurethane prepolymer is obtained. Trifunctional polyurethane acrylates containing siloxane chain segments and a preparation process thereof have also been described.

Despite above disclosures, there is still a great need in the art for more suitable polyol compositions to meet the various needs.

Contents of the Invention

The first aspect of the present invention is to provide a polyol composition, comprising: bl) at least one polyether organic polyol; b2) at least one compound having the structure of formula (1) wherein, R1 is selected from hydrogen, methyl or ethyl; R2 is selected from an alkylene having 2-6 carbon atoms, 2,2-bis(4-phenylene)-propane, 1 ,4-bis(methylene)benzene, 1,3- bis(methylene)benzene, 1 ,2-bis(methylene)benzene; n is selected from an integral number of 1-6; b3) a small molecule chain extender having a functionality of ≥2, preferably ≥3, and a hydroxyl value of ≥1200 mgKOH/g, preferably ≥1250 mgKOH/g (Test Method ISO 14900-2017).

The second aspect of the present invention is to provide a polyurethane reaction system comprising the polyol composition of present invention. In a specific embodiment, the polyurethane reaction system comprises: component A), comprising: at least one polyisocyanate; component B), comprising: the polyol composition of present invention; and component C), a free radical reaction initiator. The third aspect of the present invention is to provide a polyurethane resin prepared from the polyurethane reaction system of the present invention.

The fourth aspect of the present invention is to provide use of the polyol composition or the polyurethane reaction system of the present invention in manufacture of wind blades.

The fifth aspect of the present invention is to provide a process for preparing a polyurethane composite, which is to prepare the polyurethane composite by mixing the following components: the polyurethane reaction system of present invention; and at least one reinforcing material.

The sixth aspect of the present invention is to provide a polyurethane product which comprises the polyurethane resin of present invention. Detailed Description of the Invention

General Definition and Terms

Unless stated otherwise, the terms and phrases used herein have the following meaning. A specific term or phrase shall not be considered as unclear or indefinite when it is not specifically defined. It should be construed according to the meanings generally understood by those skilled in the art. The trade name used herein refers to the corresponding commercial product or the active ingredient.

Unless specifically defined otherwise or can be reasonably judged from the context, ratios (including percentages) or parts used herein are all by weight. When used with a numerical variable, the term “approximate” or “about” usually refers to the value of the variable and all the values of the variable within the experimental error (for example, within an average 95% confidence interval) or within ±10% of the specified value, or a wider range.

The expression “comprise” or its synonyms “contain”, “include”, “have” or the like is open- ended, which does not exclude other unlisted elements, steps or ingredients. The expression “consist of’ excludes any unlisted elements, steps or ingredients. The expression “substantially consist of’ refers to specified elements, steps or ingredients within a given range, together with optional elements, steps or components which do not substantively affect the basic and novel feature of the claimed subject matter. It should be understood that the expression “comprise” encompasses the expressions “substantially consist of’ and “consist of’.

The term “optional” or “optionally” means the event or circumstance described subsequent thereto may or may not happen. This term encompasses the cases that the event or circumstance happens or the event or circumstance does not happen.

The expression "one or more" or "at least one" can mean 1, 2, 3, 4, 5, 6, 7, 8, 9 or more. The term "and/or" encompasses "and" as well as "or". Elements defined with "and/or" mean to encompass any one and any combination thereof. For example, A and/or B encompass A, B and A+B. A, B and/or C accordingly encompass A, B, C, A+B, A+C, B+C and A±B±C.

I. polyol composition

The polyol composition provided by present invention comprises: bl) at least one organic polyol; b2) at least one compound having the structure of formula (1) wherein, R1 is selected from hydrogen, methyl or ethyl; R2 is selected from an alkylene having 2-6 carbon atoms, 2,2-bis(4-phenylene)-propane, 1 ,4-bis(methylene)benzene, 1,3- bis(methylene)benzene, 1 ,2-bis(methylene)benzene; n is selected from an integral number of 1-6; b3) a small molecule chain extender having a functionality of ≥2, preferably ≥3, and a hydroxyl value of ≥1200 mg KOH/g, preferably ≥1250 mg KOH/g (Test Method ISO 14900-2017). Organic polyol

The bl) component in the composition of present invention can be a poly ether organic polyol.

The polyether polyol can be prepared by known processes, for example, obtained by reacting an olefin oxide with a starter in the presence of a catalyst. The catalyst is preferably, but not limited to, an alkaline hydroxide, an alkaline alkoxide, antimony pentachloride, boron fluoride etherate, or a mixture thereof. The olefin oxide is preferably, but not limited to, tetrahydrofuran, ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, styrene oxide, or a mixture thereof, particularly preferably ethylene oxide and/or propylene oxide. The starter is preferably, but not limited to, polyhydroxyl compounds or polyamine compounds, the polyhydroxyl compound is preferably, but not limited to, water, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, diethylene glycol, trimethylolpropane, glycerol, bisphenol A, bisphenol S or a mixture thereof, and the polyamine compound is preferably, but not limited to, ethylene diamine, propylene diamine, butylene diamine, hexamethylene diamine, diethylene triamine, toluylene diamine or a mixture thereof.

As polyols, biobased polyether polyols can also be used. Examples include, but not limited to, vegetable oil-based polyols, such as, but not limited to, vegetable oils, vegetable oil polyols, or modified products thereof. As examples of biobased polyether polyols, cardanol-modified polyether polyols can also be used. The vegetable oil is a compound prepared from an unsaturated fatty acid and glycerol, or is an oil and fat extracted from fruits, seeds and germs of plants, and is preferably, but not limited to, peanut oil, soyabean oil, linseed oil, castor oil, rapeseed oil, and palm oil. A vegetable oil polyol is a polyol initiated from one or more vegetable oils. The starter for synthesizing the vegetable oil polyol includes, but is not limited to, soybean oil, palm oil, peanut oil, low erucic acid rapesed oil, and castor oil. A hydroxyl group can be introduced into the starter of the vegetable oil polyol through the process such as cracking, oxidation, or transesterification, and then the corresponding vegetable oil polyol can be prepared by a process well known to those skilled in the art for preparing an organic polyol. When used in the present invention, unless otherwise specified, the functionality and the hydroxyl value of the organic polyol refer to the average functionality and the average hydroxyl value. Methods for measuring the hydroxyl value are familiar to those skilled in the art. If not otherwise mentioned, hydroxyl values in this application are determined according Test Method ISO 14900-2017. In an embodiment, the bl) component is a polyether organic polyol. In another embodiment, the bl) component is selected from one or more organic polyols having the functionality of 1.7-6, and the hydroxyl value of 150-1100 mg KOH/g (Test Method ISO 14900-2017). The functionality of the polyol can be, for example, but not limited to, 1.7, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, and the like. The hydroxyl value of the polyol can be, for example, but not limited to, 150, 200, 250, 300, 350, 400, 450, 470, 500, 550, 600, 650, 700, 750, 800, 850, 900, 1000,

1100, and the like.

In a preferred embodiment, the bl) component is a propylene oxide-based poly ether polyol, starter component = glycerol, f = 3, hydroxyl value 470.

In a further embodiment, the content of the bl) component can be 30-80 wt%, preferably 35- 72 wt%, for example 35, 40, 45, 50, 55, 60, 65, 70, 72, 75 wt %, based on the total weight of the polyol composition or the total weight of component B.

Compound of structure of formula (I)

The compound of formula (I) can be prepared by conventional methods known in the art, for example may be prepared by the esterification reaction of (meth)acrylic anhydride or (meth)acrylic acid, (meth)acryloyl halide compounds and HO-(R ₂ O) _n -H.

In an embodiment, the b2) component is selected from: hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate or a combination thereof, preferably hydroxypropyl methacrylate.

In a further embodiment, the content of the b2) component can be 10-40%, preferably 15-35%, such as 10, 15, 20, 25, 30, 35, 40 wt %, based on the total weight of the polyol composition or the total weight of component B.

Small molecule chain extender

The present invention uses a small molecule chain extender. In this application, the term “small molecule chain extender” is used for compounds capable of acting as chain extenders in a polyurethane reaction system and having a functionality of ≥2, preferably ≥3, and a hydroxyl value of ≥1200 mg KOH/g, preferably ≥1250 mg KOH/g (Test Method ISO 14900-2017). Examples of useful small molecule chain extenders include, but are not limited to, glycerol, ethylene glycol, propylene glycol, butylene glycol, trimethylolpropane, pentaerythritol or a combination thereof, preferably glycerol. Its content is 2-38 wt%, preferably 3-36 wt%, based on the total weight of the polyol composition. In an embodiment, the b3) component is selected from glycerol, ethylene glycol, propylene glycol, butylene glycol, trimethylolpropane, pentaerythritol or combinations thereof, preferably glycerol.

In a preferred embodiment, the content of the b3) component is 2-38 wt %, preferably 3-36 wt %, based on the total weight of the polyol composition. In another embodiment, the content of the b3) component is 2-38 wt%, preferably 3-36 wt%, based on the total weight of the component B. For example, the content of the component b3) can be 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38 wt%, based on the total weight of the polyol composition or the total weight of component B. The present invention further relates to use of the polyol composition of present invention in the preparation of polyurethane products. The polyol composition and polyurethane product are as described herein. Preferably the polyurethane product is a wind blade.

II. Polyurethane Reaction System and Use Thereof

The polyurethane reaction system of present invention comprises: component A), comprising: at least one polyisocyanate; component B), comprising: the polyol composition of present ivention; and component C), a free radical reaction initiator.

In a specific embodiment, the polyurethane reaction system of present inventin comprises: component A), comprising: at least one polyisocyanate; component B), comprising: bl) at least one polyether organic polyol; b2) at least one compound having the structure of formula (1) wherein, R1 is selected from hydrogen, methyl or ethyl; R2 is selected from an alkylene having 2-6 carbon atoms, 2,2-bis(4-phenylene)-propane, 1 ,4-bis(methylene)benzene, 1,3- bis(methylene)benzene, 1 ,2-bis(methylene)benzene; n is selected from an integral number of 1-6; b3) a small molecule chain extender having a functionality of ≥2, preferably ≥3, and a hydroxyl value of ≥1200 mg KOH/g, preferably ≥1250 mg KOH/g (Test Method ISO 14900-2017); component C), a free radical reaction initiator.

Component A)

In an embodiment, the polyisocyanate is an organic polyisocyanate. It may be any aliphatic, cycloaliphatic, or aromatic isocyanate known to be used in the preparation of polyurethanes. Its examples include, but not limited to: toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polyphenylmethane polyisocyanate (pMDl), 1,5 -naphthalene diisocyanate (NDI), hexamethylene diisocyanate (HDI), methylcyclohexyl diisocyanate (TDI), 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate (IPDI), p-phenylene diisocyanate (PPDI), p-xylylene diisocyanate (XDI), tetramethyldimethylene diisocyanate (TMXDI) and their polymers or a combination thereof. In another embodiment, useful polyisocyanates include, but not limited to, toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polyphenylmethane polyisocyanate (pMDl), 1,5 -naphthalene diisocyanate (ND1), hexamethylene diisocyanate (HD1), methylcyclohexyl diisocyanate (TD1), 4,4'-dicyclohexylmethane diisocyanate, p-phenylene diisocyanate (PPD1), p-xylylene diisocyanate (XD1), tetramethyldimethylene diisocyanate (TMXD1) and their polymers or a combination thereof.

In an embodiment, the functionality of the isocyanate that can be used in the present invention can be 2.0-3.5, preferably 2.1-2.9.

In another embodiment, the viscosity of the isocyanate that can be used in the present invention can be 5-700 mPa*S, preferably 10-300 mPa*S, measured at 25°C according to DIN 53019- 1-3.

When used in the present invention, the (organic) polyisocyanate can comprise an isocyanate dimer, an isocyanate trimer, an isocyanate tetramer, an isocyanate pentamer, or a combination thereof.

In a preferred embodiment of the present invention, the isocyanate component A) can be selected from diphenylmethane diisocyanate (MDI), polyphenylmethane polyisocyanate

(pMDl), and their polymers, prepolymers or a combination thereof.

In an embodiment, the NCO content of the organic polyisocyanate of the present invention is 20-33 wt%, preferably 25-32 wt%, particularly preferably 30-32 wt%. The NCO content is determined by GB/T12009.4-2016. In an embodiment, the NCO content of the polyisocyanate prepolymer of the present invention is 20-33 wt%, preferably 25-32 wt%. The NCO content is determined by GB/T12009.4-2016.

In a specific embodiment, the NCO% of the (organic) polyisocyanate of the present invention is 30.5-32.5 wt% and the viscosity at 25°C is 160-240 mPa*S.

In an embodiment, the polyisocyanate content of the present invention is ≥53 wt%, preferably ≥55 wt%, more preferably 55-70 wt%, based on the total weight of the polyurethane reaction system.

Terminated-isocyanate(s) can also be used as isocyanate component A), which can be prepared through the reaction of an excessive amount of an organic polyisocyanate or mixture of organic polyisocyanates with a polyol compound. Those of ordinary skill in the art are familiar with these compounds and their preparation methods. Component B)

Each component in component B) is described as above.

In an embodiment of the present invention, the isocyanate-reactive component/polyurethance reaction system contains one or more organic polyols bl). The content of the organic polyol can be 9-60 wt%, based on 100 wt% of the total weight of the polyurethane reaction system. The bl) component can be a poly ether organic polyol.

As described above, the polyether polyols can be prepared by known processes, see for example above description.

Those skilled in the art know well the measurement method of hydroxyl value, and when used in the present invention, unless otherwise specified, the functionality and the hydroxyl value of the organic polyol refer to the average functionality and the average hydroxyl value.

In an embodiment, the bl) component is selected from one or more organic polyols having the functionality of 1.7-6, and the hydroxyl value of 150-1100 mg KOH/g (Test Method ISO 14900-2017). In another embodiment, the content of the bl) component is 9-60 wt %, preferably 10-60 wt %, based on the total weight of the polyurethane reaction system.

In an embodiment of the present invention, the isocyanate-reactive component/polyurethane reaction system further contains one or more compounds b2) having the structure of formula wherein, R1 is selected from hydrogen, methyl or ethyl; R2 is selected from an alkylene group having 2-6 carbon atoms; n is an integral number selected from 1-6.

In a preferred embodiment of the present invention, R2 is selected from ethylene, propylene, butylene, pentylene, 1 -methyl- 1,2-ethylene, 2-methyl- 1,2-ethylene, 1 -ethyl- 1,2-ethylene, 2- ethyl- 1,2-ethylene, 1 -methyl- 1,3 -propylene, 2-methyl-l, 3-propylene, 3-methyl-l,3- propylene, 1 -ethyl- 1,3 -propylene, 2-ethyl- 1,3 -propylene, 3 -ethyl- 1,3 -propylene, 1 -methyl- 1, 4-butylene, 2-methyl- 1,4-butylene, 3 -methyl- 1,4-butylene and 4-methyl- 1,4-butylene, 2,2- bis(4-phenylene)-propane, 1 ,4-dimethylenebenzene, 1,3-dimethylenebenzene, 1,2- dimethylenebenzene.

In a preferred embodiment of the present invention, the component b2) is selected from: hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate or a combination thereof.

In another embodiment, the content of the b2) component is 3-34 wt %, preferably 5-33 wt %, based on the total weight of the polyurethane reaction system.

As described above, compounds of formula (I) can be prepared by methods commonly used in the art.

As described above, the small molecule chain extender of the present invention refers to a small molecule chain extender having a functionality of ≥2, preferably ≥3, and a hydroxyl value of ≥1200 mgKOH/g, preferably ≥1250 mgKOH/g (Test Method ISO 14900-2017). Its examples include but not limited to glycerol, ethylene glycol, propylene glycol, butylene glycol, trimethylolpropane, pentaerythritol or a combination thereof, preferably glycerol. Its content is 1-11 wt%, preferably 1.2-10 wt%, more preferably 2-8.5 wt%, based on the total weight of the polyurethane reaction system.

In an embodiment, the b3) component is selected from glycerol, ethylene glycol, propylene glycol, butylene glycol, trimethylolpropane, pentaerythritol or combinations thereof, preferably glycerol.

In another embodiment, the content of b3) component is 2-38 wt%, preferably 3-36 wt%, based on the total weight of the component B.

In a specific embodiment, the content of b3) component is 1-11 wt%, preferably 1.2-10 wt%, more preferably 2-8.5 wt%, based on the total weight of the polyurethane reaction system. For example, the content ofb3) component can be 1, 1.2, 3.4, 5.8, 7.2, 8.5, 9.8, 10, 10.8, 11 wt %, based on the total weight of the polyurethane reaction system.

Component C)

In an embodiment of the present invention, the polyurethane reaction system further comprises C) free radical reaction initiator. The free-radical initiator that is used in the present invention may be added to the polyol component or the isocyanate component, or can be added to both components. These initiators include, but not limited to, peroxide, persulfide, peroxycarbonate, boric acid peroxide, azo compound, or other suitable free radical initiators that can initiate the curing of a double bond-containing compound. Its examples include but not limited to tert-butyl peroxyisopropylcarbonate, tert-butyl peroxy-3,5,5- trimethylhexanoate, methylethyl ketone peroxide, cumene hydroperoxide, tert-butyl peroxybenzoate, preferably tert-butyl peroxybenzoate.

The content of the free-radical reaction initiator is usually 0.1-8 wt%, based on 100wt% of the total weight of the isocyanate-reactive component.

The polyurethane reaction system of the present invention does not rely on light such as UV light to initiate free radical reactions. Thus, in an embodiment, the polyol composition or reaction system of the present invention does not comprises a photoinitiator, such as 2,4,6- trimethylbenzoyl-diphenylphosphine oxide (TPO).

In addition, an accelerator, such as a cobalt compound or an amine compound, may be present.

In embodiments of the present invention, the polyurethane reaction system may also comprise a catalyst for catalyzing the reaction of an isocyanate group (NCO) and a hydroxyl group (OH). An appropriate catalyst for the polyurethane reaction includes, but not limited to an amine catalyst, an organometallic catalyst, or a mixture thereof. The amine catalyst is preferably, but not limited to triethylamine, tributylamine, triethylenediamine, N-ethylmorpholine, N,N,N',N'-tetramethyl-ethylene diamine, pentamethyldiethylene-triamine, N,N- methylaniline, N,N-dimethylaniline, or a mixture thereof. The organometallic catalyst is preferably, but not limited to an organotin-tpye compound, for example: tin (11) acetate, tin (11) octoate, tin ethylhexanoate, tin laurate, dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate, dibutyltin maleate, dioctyltin diacetate, or a mixture thereof. The using amount of the catalyst is 0.001-10 wt%, based on 100wt% of the total weight of the isocyanate-reactive component.

In embodiments of the present invention, the polyurethane reaction, i.e., the addition polymerization reaction between the isocyanate group and the hydroxyl group, wherein the isocyanate group can be an isocyanate group contained in the organic polyisocyanate (component A), or an isocyanate group contained in the intermediate product of the reaction of the organic polyisocyanate (component A) and the organic polyol (bl) component) or b2) component, the hydroxyl group can be a hydroxyl group contained in the organic polyol (bl) component) or b2) component, or a hydroxyl group contained in the intermediate product of the reaction of the organic polyisocyanate (component A) and the organic polyol (bl) component) or b2) component.

In embodiments of the present invention, the free-radical polymerization reaction is an addition polymerization reaction of olefinic bonds, wherein the olefinic bonds may be an olefinic bond contained in b2) component or an olefinic bond contained in the intermediate product of the reaction of b2) component and the organic polyisocyanate.

In embodiments of the present invention, the polyurethane addition polymerization reaction (i.e., the addition polymerization reaction between the isocyanate group and the hydroxyl group) and the free radical polymerization reaction coexist. As known to those skilled in the art, suitable reaction conditions can be selected to allow the polyurethane addition polymerization reaction and the free radical polymerization reaction to proceed successively, but the polyurethane matrix prepared in this way is structurally different from the polyurethane resin matrix prepared by allowing the polyurethane addition polymerization reaction and the free radical polymerization reaction to proceed simultaneously, so that the prepared polyurethane composites are different in mechanical properties and manufacturability.

In embodiments of the present invention, the above-mentioned polyurethane reaction system can also contain auxiliaries or additives including, but not limited to: filler, internal release agent, flame retardant, smoke suppressant, dye, pigment, antistatic agent, antioxidant, UV stabilizer, diluent, defoamer, coupling agent, surface wetting agent, leveling agent, water- scavenger, catalyst, molecular sieve, thixotropic agent, plasticizer, foaming agent, foam stabilizing agent, foam stabilizer, free radical reaction suppressant or a combination thereof. These components may be optionally contained in the isocyanate component A) and/or the isocyanate-reactive component B). These components can also be independently stored as component D) and, when used for preparing a polyurethane composite, are mixed with the isocyanate component A) and/or the isocyanate-reactive component B) before the preparation.

In some embodiments of the present invention, the filler includes but not limited to aluminum hydroxide, bentonite, pulverized fuel ash, wollastonite, perlite powder, hollow microsphere, calcium carbonate, talcum powder, mica powder, porcelain clay, fumed silica, expandable microsphere, diatomite, volcanic ash, barium sulfate, calcium sulfate, glass microsphere, stone powder, wood flour, wood chip, bamboo powder, bamboo chip, rice grain, straw chips, sorghum straw chips, graphite powder, metal powder, thermosetting composite recycled powder, plastic particle or powder, or a combination thereof. Among others, the glass microspheres can be solid or hollow. The internal release agent that can be used in the present invention comprises any release agent conventionally used for producing polyurethanes, and examples thereof include but not limited to long-chain carboxylic acids, particularly fatty acids such as stearic acid, amides of long- chain carboxylic acids such as stearic amide, fatty acid esters, metal salts of long-chain carboxylic acids such as zinc stearate, or polysiloxanes.

Examples of flame retardants that can be used in the present invention include but not limited to triaryl phosphates, trialkyl phosphates, triaryl phosphates or trialkyl phosphates with halogen, melamine, melamine resins, halogenated paraffins, red phosphorus, or combinations thereof. Other auxiliaries that can be used in the present invention include but not limited to water- scavengers such as molecular sieves; defoamers such as polydimethyl siloxane; coupling agents such as mono(ethylene oxide) or organic amine functionalized trialkoxysilane or combinations thereof. Coupling agents are particularly preferably for improving the adhesion of the resin matrix to the fiber reinforcing material. Fine particle fillers, such as clay and fumed silica, are commonly used as thixotropic agent.

The free radical reaction suppressant that can be used in the present invention includes polymerization inhibitors and polymerization retarders, and the like, for example, some phenols, quinone compounds or hindered amine compounds. Examples thereof include methyl hydroquinone, p-methoxyphenol, benzoquinone, polymethyl piperidine derivatives, low- valent copper ions, and the like.

The present invention further relates to use of the polyurethane reaction system of present invention in the preparation of polyurethane products. The polyol composition and polyurethane product are as described herein. Preferably the polyurethane product is a wind blade.

III. Polyurethane Resin

Accordingly the polyurethane resin of present invention can be prepared by the polyurethane reaction system of the present invention. The polyurethane of the present invention has particularly excellent effects, including but not limited to at least one of the following aspects.

The polyurethane resin prepared from reaction of the polyurethane reaction system has a heat deflection temperature of ≥105°C, preferably ≥110°C, more preferably ≥120°C (Test Method ISO 75-22013).

Compared to the heat deflection temperature of the polyurethane resin prepared from reaction of the polyurethane reaction system without component b3), the heat deflection temperature of the polyurethane resin prepared from reaction of the polyurethane reaction system comprising component b3) is increased by ≥5%, preferably ≥10%, more preferably ≥15% (Test Method ISO 75-22013).

The polyurethane resin has a heat deflection temperature of ≥105°C, preferably ≥110°C, more preferably ≥120°C (Test Method ISO 75-22013).

IV. Polyurethane Composite and Preparation thereof

The present invention further provides a process for preparing a polyurethane composite, wherein the polyurethane composite comprises a polyurethane resin matrix and a reinforcing material, the process comprises a step of preparing the polyurethane resin matrix under such reaction conditions that both the free radical polymerization reaction and the reaction between the isocyanate group and the hydroxyl group are present in the polyurethane reaction system, wherein the polyurethane reaction system is described above.

In an embodiment, the polyurethane resin prepared from the polyurethane reaction system has a heat deflection temperature of ≥105°C, preferably ≥110°C, more preferably ≥120°C.

In another embodiment, compared to the heat deflection temperature of the polyurethane resin prepared from reaction of the polyurethane reaction system without component b3), the heat deflection temperature of the polyurethane resin prepared from reaction of the polyurethane reaction system comprising component b3) is increased by ≥5%, preferably ≥10%, more preferably ≥15%. In a specific embodiment, the process of present inventin for preparing polyurethane composite inclues mixing the following components so as to prepare the polyurethane composite: the polyurethane reaction system of present invention; and, at least one reinforcing material.

In an embodiment, the polyurethane addition polymerization reaction (i.e., the addition polymerization reaction between the isocyanate group and the hydroxyl group) and the free radical polymerization reaction coexist.

In an embodiment, the polyurethane composite is prepared through pultrusion process, filament winding process, hand lay-up moulding process, vacuum infusion process, spray lay up moulding process or a combination thereof.

In a specific embodiment, the polyurethane composite of the present invention can be prepared by a polyurethane vacuum infusion process. The operation procedure for the polyurethane vacuum infusion process is well known to those skilled in the art.

As an example, in the vacuum infusion process, one or more cores are provided in a mould, and the core is optionally covered wholly or partly by a reinforcing material. Then, a negative pressure is formed in the mould to perfuse the polyurethane resin into the mould; before curing, the polyurethane resin will wholly soak the reinforcing material and the core will be wholly or partly soaked by the polyurethane resin. Then, under appropriate conditions, the polyurethane resin is allowed to simultaneously undergo the polyurethane addition polymerization reaction and the free-radical polymerization reaction, thereby curing the polyurethane resin to form a polyurethane resin matrix. In the above vacuum infusion process, the mould may be a mould commonly used in the art, and a person skilled in the art can select a suitable mould according to the desired properties and dimensions of the final product. In case of preparing a large article by using the vacuum infusion process, in order to ensure a sufficient pot-life, it is necessary to have the resin to keep a sufficiently low viscosity during the infusion to maintain good flowability. If the viscosity is higher than 600mPas, the resin viscosity is considered as being too high, the flowability becomes worse, and the resin is no longer suitable for vacuum infusion process.

The core is used together with the polyurethane resin matrix and the reinforcing material so as to facilitate the molding of the composite material and the reduction of the weight of the composite material. The cores commonly used in the art can be used in the polyurethane composite of the present invention, and their examples include, but not limited to polystyrene foams, for example COMPAXX ^® foam; polyester PET foams; polyimide PM1 foams; polyvinyl chloride foams; metal foams, such as those available from Mitsubishi; balsa wood; and the like.

In other embodiments, the reinforcing material can be a material including glass fiber, carbon nanotube, carbon fiber, polyester fiber, natural fiber, aromatic polyamide fiber, nylon fiber, basalt fiber, boron fiber, silicon carbide fiber, asbestos fiber, crystal whisker, hard particles, metal fiber or a combination thereof. In an embodiment, the content of the reinforcing material is A 40 wt %, preferably A 45 wt %, more preferably 50-88 wt %, based on the total weight of the polyurethane composite.

The polyurethane reaction system of the present invention can be suitable for being used in the polyurethane vacuum infusion process to prepare the polyurethane composite, and has a relatively long pot-life, and the polyurethane composite prepared by the polyurethane vacuum infusion process has good mechanical properties, especially a relatively high heat-deflection temperature, so that the problem that the pot-life of the polyurethane reaction system and the heat-deflection temperature of the prepared polyurethane composite cannot be improved at the same time in the prior art is solved. These polyurethane composites can be used in the production of blades of wind-driven generators, enclosures for wind-driven generators, ship blades, ship shells, internal and external decorations and shells of vehicles, radar housings, structural part materials of mechanical equipments, and decorations and structural parts of buildings and bridges. The fan as mentioned in the present invention comprises a wind-driven generator, a turbo fan and the like.

The polyurethane composite of the present invention can also be prepared through the pultrusion process, the filament winding process, the hand lay-up moulding process, the spray lay-up moulding process or a combination thereof.

Accordingly, the present invention further provides a polyurethane composite, which is prepared by the aforementioned process of the present invention for preparing a polyurethane composite.

V. Polyurethane Product

The present invention further provides a polyurethane product. The polyurethane product comprises the aforementioned polyurethane resin of the present invention. The polyurethane product may include the polyurethane composite of the present invention. In an embodiment, the polyurethane product can be selected from cable trays, frames of doors, windows and curtain walls, frames of ladders, tent poles or pipes, anti-glare shields, floors, sucker rods, telegraph poles and cross arms, guardrails, grills, architectural profiles, container profiles and plates, bike racks, fishing rods, cable cores, insulator core rods, antenna housings, single-layer or sandwiched continuous plates, wind blades or parts thereof, enclosures for wind-driven generators, ship blades, ship shells, internal and external decorations and shells of vehicles, radar housings, structural part materials of mechanical equipments, decorations and structural parts of buildings and bridges, preferably wind blades or parts thereof, enclosures for wind-driven generators, more preferably blade shells, webs, spar caps, main spars, auxiliary spars and blade roots of wind blades.

Advantageous effects

Surprisingly, the inventors have found that the polyol composition of the present invention, which comprises a selected small molecule chain extender, and a polyol and a compound having the structure of formula (I) compatible thereto, can greatly increase the heat deflection temperature of the resin prepared therefrom, thereby enabling the resin to be suitable for a wider variety of applications, such as large articles for outdoor use, e.g., wind blades, ship parts, and the like. The prepared relevant products have better quality, and meanwhile are more temperature-resistant and wear-resistant, enabling an extended service life. In addition, the maintenance and replacement can be reduced, thereby saving raw materials, manpower and material resources and being more environment- friendly.

Furthermore, small molecule chain extenders, including glycerol, generally have an obvious price advantage over polyols. Therefore, the polyol composition of the present invention can greatly save costs and increase economic benefits while improving product quality, thereby promoting the popularization and application of related products. Some exemplary embodiments of the present invention are listed as follows:

Embodiment 1. A polyol composition, comprising: bl) at least one organic polyol; b2) at least one compound having the structure of formula (I) wherein, R1 is selected from hydrogen, methyl or ethyl; R2 is selected from an alkylene having 2-6 carbon atoms, 2,2-bis(4-phenylene)-propane, 1 ,4-bis(methylene)benzene, 1,3- bis(methylene)benzene, 1 ,2-bis(methylene)benzene; n is selected from an integral number of 1-6; b3) a small molecule chain extender having a functionality of ≥2, preferably ≥3, and a hydroxyl value of ≥1200 mgKOH/g, preferably ≥1250 mgKOH/g (Test Method ISO 14900-2017).

Embodiment 2. The polyol composition according to embodiment 1, characterized in that said b3) component is selected from glycerol, ethylene glycol, propylene glycol, butylene glycol, trimethylolpropane, pentaerythritol or a combination thereof, preferably glycerol.

Embodiment 3. The polyol composition according to embodiment 1 or 2, characterized in that the content of said b3) component is 2-38 wt%, preferably 3-36 wt%, based on the total weight of the polyol composition.

Embodiment 4. A polyurethane reaction system, comprising: component A), comprising: at least one polyisocyanate; component B), comprising: bl) at least one organic polyol; b2) at least one compound having the structure of formula (I) wherein, R1 is selected from hydrogen, methyl or ethyl; R2 is selected from an alkylene having 2-6 carbon atoms, 2,2-bis(4-phenylene)-propane, 1 ,4-bis(methylene)benzene, 1,3- bis(methylene)benzene, 1 ,2-bis(methylene)benzene; n is selected from an integral number of 1-6; b3) a small molecule chain extender having a functionality of ≥2, preferably ≥3, and a hydroxyl value of ≥1200 mgKOH/g, preferably ≥1250 mgKOH/g (Test Method ISO 14900-2017); component C), a free radical reaction initiator.

Embodiment 5. The polyurethane reaction system according to embodiment 4, characterized in that said b3) component is selected from glycerol, ethylene glycol, propylene glycol, butylene glycol, trimethylolpropane, pentaerythritol or a combination thereof, preferably glycerol.

Embodiment 6. The polyurethane reaction system according to embodiment 4 or 5, characterized in that the content of said b3) component is 1-11 wt%, preferably 1.2-10 wt%, more preferably 2-8.5 wt%, based on the total weight of the polyurethane reaction system.

Embodiment 7. The polyurethane reaction system according to any of embodiments 4-6, characterized in that the polyurethane resin prepared from the reaction of the polyurethane reaction system has a heat deflection temperature of ≥105°C, preferably ≥110°C, more preferably ≥120°C (Test Method ISO 75-22013).

Embodiment 8. The polyurethane reaction system according to any of embodiments 4-7, characterized in that compared to the heat deflection temperature of the polyurethane resin prepared from the reaction of the polyurethane reaction system without component b3), the heat deflection temperature of the polyurethane resin prepared from the reaction of the polyurethane reaction system comprising component b3) is increased by ≥5%, preferably ≥10%, more preferably ≥15% (Test Method ISO 75-22013).

Embodiment 9. A polyurethane resin, prepared from the reaction of the polyurethane reaction system according to any of embodiments 4-8.

Embodiment 10. The polyurethane resin according to embodiments 9, characterized in that said polyurethane resin has a heat deflection temperature of ≥105°C, preferably ≥110°C, more preferably ≥120°C (Test Method ISO 75-22013).

Embodiment 11. Use of the polyurethane reaction system according to any of embodiments 4- 8 in manufacture of wind blades.

Embodiment 12. A process for preparing a polyurethane composite, which is to prepare the polyurethane composite by mixing the following components: the polyurethane reaction system according to any of embodiments 4-8; and at least one reinforcing material.

Embodiment 13. The process according to embodiment 12, characterized in that the polyurethane composite is prepared through pultrusion process, filament winding process, hand lay-up moulding process, vacuum infusion process, spray lay-up moulding process or a combination thereof, preferably through vacuum infusion process and/or pultrusion process.

Embodiment 14. The process according to embodiment 12 or 13, characterized in that the process comprises the coexistence of free radical polymerization reaction and addition polymerization reaction between isocyanate groups and hydroxyl groups.

Embodiment 15. The process according to any of embodiments 12-14, characterized in that the polyurethane resin prepared from the reaction of the polyurethane reaction system has a heat deflection temperature of ≥105°C, preferably ≥110°C, more preferably ≥120°C.

Embodiment 16. A polyurethane composite prepared by the process for preparing a polyurethane composite according to any of embodiments 12-15.

Embodiment 17. The polyurethane composite according to embodiment 16, characterized in that the content of the reinforcing material in the polyurethane composite is ≥40wt%, preferably ≥45wt%, more preferably 50-88wt%, based on the total weight of the polyurethane composite.

Embodiment 18. A polyurethane product comprising the polyurethane resin of embodiment 9 or 10, characterized in that the polyurethane product is selected from cable trays, frames of doors, windows and curtain walls, frames of ladders, tent poles or pipes, anti-glare shields, floors, sucker rods, telegraph poles and cross arms, guardrails, grills, architectural profiles, container profiles and plates, bike racks, fishing rods, cable cores, insulator core rods, antenna housings, single-layer or sandwiched continuous plates, wind blades or parts thereof, enclosures for wind-driven generators, ship blades, ship shells, internal and external decorations and shells of vehicles, radar housings, structural part materials of mechanical equipments, decorations and structural parts of buildings and bridges, preferably wind blades or parts thereof, enclosures for wind-driven generators, more preferably blade shells, webs, spar caps, main spars, auxiliary spars and blade roots of wind blades.

The present invention will be further described with reference to the specific examples. It is to be understood, however, that these examples are illustrative only and are not to be construed to limit the scope of the present invention. Examples

The test methods for which no specific conditions are indicated in the following examples are generally performed based on conventional conditions or according to conditions recommended by the manufacturer. Unless otherwise stated, all percentages and parts are by weight.

“pbw” refers to the parts by weight of each component in the polyurethane reaction system;

“Functionality” refers to the value determined according to the industry formula: functionality=hydroxyl value * molecular weight/56100; wherein the molecular weight is determined by GPC high performance liquid chromatography;

“Heat deflection temperature (HDT)” refers to the temperature at which a plastic material can maintain a constant shape at high temperature and under pressure. It is generally used to indicate the short-term heat resistance of plastic. The heat deflection temperature of the present invention is measured according to ISO 75-22013. “Isocyanate index” refers to a value calculated by the following formula:

Isocyanate index (%) = (mole number of isocyanate group (NCO group) in component A/mole number of isocyanate group-reactive group in component B)x 100%.

The raw materials used in the examples are as follows:

Isocyanate Desmodur 1511L: NCO%: 30.5-32.5%, viscosity at 25°C: 160-240 mPa*s, purchased from Covestro Polymers (China) Co., Ltd.; t-butyl peroxybenzoate (TBPB): purchased from AkzoNobel;

NL-49P: purchased from AkzoNobel;

Polyol: propylene oxide-based polyether polyol, starter component = glycerol, f = 3, hydroxyl value 470, purchased from Covestro Polymers (China) Co., Ltd.; Hydroxypropyl methacrylate (HPMA): purchased from Hersbit Chemical;

Glycerol: purchased from Aladdin. Examples El -6 and Comparative Examples Cl -2

Preparation of polyol component (component B): according to the component proportions in Table 1, the polyol, glycerol, HPMA, NL-49P and the like were weighed, and quickly stirred for 30 seconds (rotation speed per minute: 3000rpm); the polyol component was allowed to stand by for 1 day, and observed for whether it was uniform and transparent or it stratified.

Preparation of isocyanate component (component A): according to the component proportions in Table 1, TBPB and 1511L were weighed, successively added to another plastic cup, and stirred to become uniform.

The isocyanate and polyol components were weighed according to the proportion of each component in Table 1, placed in a new plastic cup, rapidly stirred for 30 seconds (3000 rpm), and then placed in a flat-plate mould which had been preheated to 80°C in an oven. Then the oven door was closed, the temperature in the oven was quickly increased by heating to 170°C in 15 minutes, and then preserved at 170°C for 15 minutes. The heating of the oven was stopped, and the cured resin plate was naturally cooled to room temperature. The oven was opened, and the resin plate was taken out and measured for its corresponding heat deflection temperature. The test results were shown in Table 1.

As could be seen from Table 1, compared with Comparative Example Cl, Examples El -6 could significantly increase their heat deflection temperature without changing the amount of HPMA, but only by adding part of glycerol into the polyol component, and the mutual solubility of the components of the polyol component was kept well and the polyol component was clear and transparent without stratification. However, if the addition amount of glycerol was too high, the mutual solubility became poor and the polyol component stratified. The stratification of the polyol component could be detrimental to daily operation and use. Moreover, in the comparison between E6 and C2, it could be seen that further increasing the amount of glycerol resulted in not only the worse mutual solubility and the stratification, but also no longer significant increase in the heat deflection temperature.