Polyurethane composition and polyurethane composite material

Abstract

The present invention relates to the technical field of polyurethane compositions, particularly to a polyurethane composition and a polyurethane composite material, the polyurethane composition comprises an isocyanate component, an isocyanate reactive component, a catalyst and an optional auxiliary agent, the viscosity of the isocyanate reactive component at 25 DEG C is 400-700 mPa.s; the isocyanate reactive component includes: a low viscosity polyol; the viscosity at 25 DEG C is smaller than or equal to 200 mPa.s, the hydroxyl value is larger than or equal to 1000 mgKOH / g, and the primary alcohol is the primary alcohol with the average functionality larger than or equal to 2; the time required for increasing the real-time mixing viscosity eta t of the isocyanate component and the isocyanate reactive component by 100% at 25 DEG C compared with the initial mixing viscosity eta 0 is t, and t is greater than or equal to 200 s and greater than or equal to 660 s. The polyurethane composition disclosed by the invention is applied to a composite material pultrusion process, rapid pultrusion can be realized, the pultrusion efficiency of polyurethane is remarkably improved, and meanwhile, the performance of an obtained composite material is excellent.

Description

Technical Field

[0001] This invention relates to the field of polyurethane technology, and more particularly to a polyurethane composition and a polyurethane composite material. Background Technology

[0002] Polyurethane pultruded profiles are characterized by high strength, low thermal conductivity, insulation, and corrosion resistance, making them suitable for applications such as energy-saving doors and windows and photovoltaic frames. However, the current production efficiency of polyurethane pultrusion processes is generally ≤0.8m / min, which is relatively low and severely restricts the development of the polyurethane pultrusion industry.

[0003] In the production of polyurethane pultruded profiles, liquid polyurethane resin and solid reinforcing materials (such as glass fiber) are impregnated. Each glass fiber filament needs to be fully impregnated with the liquid polyurethane resin. Insufficient impregnation between the glass fiber and the liquid polyurethane resin can lead to inconsistent glass fiber content in the pultruded profile, deteriorated surface quality, profile deformation, and decreased yield. More seriously, it can cause mold blockage during production, resulting in shutdowns and severely impacting production efficiency and costs. Furthermore, as the pultrusion rate increases, the impregnation time for both glass fiber and liquid polyurethane resin decreases, further reducing the impregnation degree and causing problems in the pultruded profiles. Therefore, the industry has made numerous attempts to improve the impregnation degree between glass fiber and liquid polyurethane resin.

[0004] Patent document CN116925314A discloses an isocyanate reactive composition for preparing polyurethane composites, in which glycerol and diethylene glycol are used as chain extenders to reduce the viscosity of the system and accelerate the wetting between glass fibers and liquid polyurethane resin to meet the requirements of faster linear speeds during pultrusion. However, this method only achieves the purpose of reducing the viscosity of the raw materials by adding a substance that can reduce viscosity, and its control over the reaction process during the wetting stage is insufficient.

[0005] During pultrusion, the real-time viscosity of the resin affects the impregnation rate and the effective adsorption thickness of the resin layer on the fiber. Failure to control the reaction process of the polyurethane composition during the impregnation stage will severely impact the resin's performance and its processing characteristics.

[0006] Therefore, there is an urgent need for a polyurethane resin system that satisfies both viscosity control and rapid pultrusion, in order to improve pultrusion processing efficiency and contribute to the development of the pultrusion industry. Summary of the Invention

[0007] The purpose of this invention is to address the technical problems existing in the pultruded polyurethane composite profiles of the prior art. This invention provides a polyurethane composition and a polyurethane composite material. When applied to the composite material pultrusion process system, the polyurethane composition can achieve rapid pultrusion, significantly improve the polyurethane pultrusion processing efficiency, and the resulting composite profile has excellent performance.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] In a first aspect, a polyurethane composition is provided, the polyurethane composition comprising an isocyanate component and an isocyanate reactive component, wherein:

[0010] (A) The isocyanate reactive component has a viscosity of 400 mPa·s to 700 mPa·s at 25°C (e.g., 420 mPa·s, 450 mPa·s, 500 mPa·s, 550 mPa·s, 600 mPa·s, 650 mPa·s, 680 mPa·s);

[0011] The isocyanate reactive component includes: component i), a low-viscosity polyol; the low-viscosity polyol has a viscosity of ≤200 mPa·s at 25°C (e.g., 180 mPa·s, 150 mPa·s, 120 mPa·s, 100 mPa·s, 80 mPa·s, 60 mPa·s, 50 mPa·s, 40 mPa·s, 20 mPa·s, 10 mPa·s), and a hydroxyl value ≥1000 mgKOH / g (e.g., 1100 mgKOH / g, 1200 mgKOH / g, 1400 mgKOH / g, 1500 mgKOH / g, 1800 mgKOH / g, 2000 mgKOH / g), and is a primary alcohol with an average functionality ≥2 (e.g., 3, 4);

[0012] (B) Real-time mixing viscosity η of the isocyanate component and the isocyanate reactive component at 25°C t The time required for the initial mixed viscosity η0 to increase by 100% is t, which satisfies 660s≥t≥200s. For example, t is 210s, 220s, 240s, 250s, 280s, 300s, 350s, 400s, 450s, 500s, 550s, 580s, 600s, 620s, 640s, and 650s.

[0013] In this document, the polyurethane composition is a two-component polyurethane resin, wherein the isocyanate component is prepared and stored separately as component B; and the isocyanate reactive component, catalyst, and optional additives are prepared and stored separately as component A.

[0014] In this article, the term "isocyanate reactive component" can be understood as an organic polyol or a mixture thereof used in the preparation of polyurethane polymer materials in this field.

[0015] In this article, "low viscosity polyol" can be understood as an organic polyol used to prepare polyurethane polymer materials, which is a single organic polyol or a mixture of multiple organic polyols.

[0016] In some embodiments of the polyurethane composition provided by the present invention, the low-viscosity polyol is selected from one or more of ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,4-butanediol, 2-methylpropanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, and dipropylene glycol.

[0017] In some embodiments, the low-viscosity polyol accounts for 1 wt% to 10 wt% of the total mass of the isocyanate reactive component, for example, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 8 wt%.

[0018] In some embodiments, the isocyanate reactive component further includes: component ii), which is selected from one or more of polyether polyols, polyester polyols, polyether carbonate polyols, polycarbonate polyols and bio-based polyols, preferably selected from one or more of polyether polyols, polyester polyols and bio-based polyols; more preferably polyether polyols and / or polyester polyols.

[0019] In some embodiments, the content of component ii) is 90-99 wt% of the total mass of the isocyanate reactive component, for example, 92 wt%, 94 wt%, 95 wt%, 96 wt%, 98 wt%.

[0020] The polyether polyols generally refer to a series of organic polyols that can be prepared using existing processes. They are mainly obtained by using polyols as initiators, epoxides as polymerization monomers, and undergoing a chemical reaction under the action of a catalyst to obtain a class of polyol compounds.

[0021] In this document, the initiator used to form the polyether polyol may be selected from one or more of ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1-pentanediol, hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, diethylene glycol, neopentanediol, glycerol, trimethylolpropane, pentaerythritol, sorbitol, bisphenol A, and bisphenol S; and the epoxide used to form the polyether polyol may be selected from one or more of ethylene oxide, propylene oxide, 1,2-epoxybutane, 2,3-epoxybutane, tetrahydrofuran, and styrene oxide; and the catalyst used to form the polyether polyol may be selected from one or more of basic hydroxides, basic alkoxides, and antimony pentachloride.

[0022] The polyester polyols generally refer to a class of polyol compounds formed by the condensation (or transesterification) of organic dicarboxylic acids (anhydrides or esters) with polyols or by the polymerization of lactones with polyols.

[0023] In this document, the diacid used to form the polyester polyol may be selected from one or more of phthalic acid, phthalic anhydride, phthalate ester, adipic acid, and halophthalic acid; and the polyol used to form the polyester polyol may be selected from one or more of ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1-pentanediol, hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, diethylene glycol, neopentanediol, glycerol, trimethylolpropane, pentaerythritol, sorbitol, bisphenol A, and bisphenol S; and the lactone used to form the polyester polyol may be selected from one or more of butyrolactone, dodecyl lactone, and tetradecyl lactone.

[0024] In this article, the polyether carbonate polyol is typically prepared by using a cyanide containing a bimetallic element as a catalyst to react carbon dioxide with an epoxy compound on a starting material containing active hydrogen atoms.

[0025] In this article, the bio-based polyols are oligomeric polyols obtained from animal and plant materials, which are renewable resources; animal and plant materials include, but are not limited to, vegetable oils, animal fats, wood, rosin, starch, or mixtures thereof; vegetable oils may be compounds prepared from unsaturated fatty acids and glycerol or oils extracted from plant fruits, neutrons, germs, or mixtures thereof, including but not limited to castor oil, rapeseed oil, palm oil, soybean oil, peanut oil, etc.

[0026] In this article, the term "catalyst" can be understood as a polyurethane catalyst in the field of polyurethane materials, which can effectively catalyze the addition reaction between isocyanate groups and hydroxyl groups.

[0027] In some embodiments, the polyurethane composition further includes a catalyst.

[0028] In some embodiments, the catalyst is an amine catalyst or an organometallic catalyst, preferably selected from one or more of triethylamine, tributylamine, triethylenediamine, N-ethylmorpholine, N,N,N',N'-tetramethyl-ethylenediamine, pentamethyldiethylene-triamine, N,N-methylaniline, N,N-dimethylaniline, tin(II) acetate, tin(II) octoate, tin ethylhexanoate, tin laurate, dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate, dibutyltin maleate, and dioctyltin diacetate.

[0029] In some embodiments, the catalyst is used in an amount of 0 to 1 wt% (e.g., 0.01 wt%, 0.05 wt%, 0.15 wt%, 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.8 wt%) of the total weight of the isocyanate reactive components, preferably 0.1 wt% to 1 wt%.

[0030] In some embodiments, the isocyanate index of the polyurethane composition is 0.9 to 1.3, for example, 0.95, 1.0, 1.1, 1.2, or 1.25. The isocyanate index is well known to those skilled in the art and will not be described further herein.

[0031] In this article, "isocyanate components" refers to organic isocyanate monomers, isocyanate prepolymers, epoxy-modified isocyanates, unsaturated modified isocyanates, phenolic modified isocyanates, and mixtures thereof that are commonly found in the art and have -NCO groups.

[0032] In some embodiments, the isocyanate component is selected from toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, naphthalene diisocyanate, terephthalic diisocyanate, 1,4-cyclohexane diisocyanate, phenylenediamine diisocyanate, cyclohexane diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, tetramethyl-m-phenylenediamine diisocyanate, norbornene diisocyanate, dimethylbiphenyl diisocyanate, methylcyclohexyl diisocyanate, tetramethylene diisocyanate, 2-methylpentamethylene diisocyanate. One or more of the following: dodecyl methylene diisocyanate, 4,4'-diisocyanate-3,3'-dimethyldicyclohexylmethane, 4,4'-diisocyanate-2,2-dicyclohexylpropane, poly(hexamethylene diisocyanate), octamethylene diisocyanate, toluene-α,4-diisocyanate, 2,4,6-trimethyl-1,3-phenylene diisocyanate, 4-chloro-6-methyl-1,3-phenylene diisocyanate, poly(tetrafluoroethylene oxide-co-difluoromethyleneoxy)α,ω-diisocyanate, 1,4-butane diisocyanate, 1,8-octane diisocyanate, and their isocyanate prepolymers and modified products.

[0033] In some embodiments, the polyurethane composition further includes additives. Hereinafter, "additives" refers to functional additives or auxiliaries used in the polyurethane composition; these functional additives and auxiliaries include, but are not limited to, internal release agents, flame retardants, fillers, pigments, antioxidants, foaming stabilizers, light stabilizers, auxiliary antioxidants, hydrolytic stabilizers, bactericides and fungicides, defoamers, rheology modifiers, leveling agents, wetting agents, reactive diluents, coupling agents, color pastes, catalysts, dehydrating agents, molecular sieves, or mixtures of the above additives and auxiliaries. These components may be stored independently of the polyurethane composition system.

[0034] In some embodiments, the additives are selected from one or more of the following: internal release agents, flame retardants, fillers, pigments, antioxidants, foaming agents, stabilizers, light stabilizers, auxiliary antioxidants, hydrolytic stabilizers, bactericides and fungicides, defoamers, rheology modifiers, leveling agents, wetting agents, reactive diluents, coupling agents, color pastes, catalysts, dehydrating agents, and molecular sieves.

[0035] In a second aspect, a polyurethane composite material is provided, the composite material comprising:

[0036] (a) A polyurethane resin matrix comprising 15 to 25 wt% (e.g., 16 wt%, 18 wt%, 20 wt%, 22 wt%, 24 wt%) of the total weight of the composite material, wherein the polyurethane resin matrix is ​​obtained by means of the polyurethane composition described above;

[0037] (b) A reinforcing material comprising 75 to 85 wt% (e.g., 76 wt%, 78 wt%, 80 wt%, 82 wt%, 84 wt%) of the total weight of the composite material;

[0038] The reinforcing material is a fibrous material, preferably selected from at least one of glass fiber, carbon fiber, polyester fiber, natural fiber, nylon fiber, aromatic polyamide fiber, basalt fiber, boron fiber, silicon carbide fiber, asbestos fiber, whiskers and metal fiber.

[0039] According to some embodiments of the polyurethane composite material provided by the present invention, the preparation process of the composite material is as follows: the polyurethane resin matrix and the reinforcing material are mixed evenly in proportion, and then processed and molded into an article.

[0040] In some embodiments, during the processing and molding of the composite material, the isocyanate reactive component, catalyst, and optional additives (component A) are thoroughly premixed with the isocyanate component (component B). During this premixing process, the materials are mixed using a polyurethane-specific dispensing machine or a handheld mechanical mixer.

[0041] In some implementations, the composite material is processed and formed using a pultrusion molding process.

[0042] In the processing and molding of the composite material described in this article, the isocyanate reactive component, catalyst, and optional additives, which are components A, are fully premixed with the isocyanate component, which is component B, to obtain a polyurethane composition; then, it is processed into composite profile products through a pultrusion molding process.

[0043] If the polyurethane resin reacts too quickly during the pultrusion process of polyurethane composite profiles, the viscosity of the resin in the injection box will rise rapidly, severely affecting the wetting efficiency between the resin and the reinforcing material (such as glass fiber), and may even cause the resin to gel prematurely, resulting in mold blockage. If the polyurethane resin reacts too slowly, the resin layer in the reinforcing material will not be thick enough, requiring a significant increase in the amount of reinforcing material. However, increasing the amount of reinforcing material will cause wetting problems between the resin and the fiber, leading to poor controllability and large fluctuations in the pultrusion process, as well as unqualified profile appearance.

[0044] The inventors have discovered that the real-time viscosity of the polyurethane resin during the pultrusion process of polyurethane composite profiles affects its wetting rate of the reinforcing material and the effective adsorption thickness of the resin layer in the reinforcing material. By controlling the content of low-viscosity primary alcohol in the isocyanate reactive component to 1-10 wt%, the viscosity of the isocyanate reactive component at 25°C is 400 mPa·s to 700 mPa·s. This effectively controls the reaction process between the components in the polyurethane composition, ensuring effective wetting of the resin into reinforcing materials such as fibers. Furthermore, by controlling the amount of catalyst, the polyurethane composition of this invention allows for controllable viscosity during the injection molding process and enables stable and rapid pultrusion during processing (composite profiles are prepared under high-speed pultrusion conditions with a linear speed of 1.5 m / min). Detailed Implementation

[0045] To provide a detailed understanding of the technical features and content of this invention, preferred embodiments will be described in more detail below. While preferred embodiments are described in the examples, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply.

[0046] Sources of main raw materials:

[0047] Isocyanate component: WANNATE PM200, NCO content 31.2wt%, Wanhua Chemical;

[0048] Glycerin: Purchased from Aladdin;

[0049] Diethylene glycol: purchased from Maclean's;

[0050] Ethylene glycol: purchased from Aladdin;

[0051] 2,3-Butanediol: Purchased from Beijing Bailingwei Technology Co., Ltd.;

[0052] Polyol 1: Glycerol was used as a starting agent and propylene oxide was polymerized. The molecular weight was 280, the hydroxyl value was 600 mg KOH / g, and the viscosity at 25°C was about 600 mPa·s.

[0053] Polyol 2: Glycerol was used as a starting agent and propylene oxide was polymerized. The molecular weight was 500, the hydroxyl value was 340 mg KOH / g, and the viscosity at 25°C was about 300 mPa·s.

[0054] Polyol 3: Ethylene glycol as the initiator, propylene oxide polymerization, molecular weight 3000, hydroxyl value 37mgKOH / g, viscosity at 25℃ is about 1200mPa·s;

[0055] Catalyst: Tin lauryl sulfate;

[0056] Internal release agent: HB-650D, TECHNICK PRODUCTS;

[0057] Reinforcing material: ECT 467R-4800 glass fiber, purchased from Chongqing International Composite Materials Co., Ltd.

[0058] Main testing methods:

[0059] The standard for flexural modulus testing is DIN ISO 527.

[0060] The standard for bending strength testing is DIN ISO 527;

[0061] The standard for tensile strength testing is DIN ISO 527;

[0062] The standard for tensile modulus testing is DIN ISO 527.

[0063] Resin Curing Degree Test: The total heat release (denoted as Q) of mixing the isocyanate component and the isocyanate reactive component to achieve complete curing was measured using a Mettler Toledo DSC822e differential scanning calorimeter. total After demolding, a cured resin sample without any treatment was taken and subjected to DSC testing until fully cured. The heat release (denoted as Q) was recorded. sample Throughout all tests, the selected test conditions remained consistent, and the degree of ripening was then calculated using the following formula:

[0064] degree of ripening = (1-Q) sample / Q total )*100%.

[0065] Example 1

[0066] The preparation steps of the polyurethane resin matrix are as follows:

[0067] (1) Weigh each polyol, catalyst and auxiliary agent according to the formula shown in Table 1 and add them to a mixing container. Mechanically stir at 25°C and mix the materials evenly at a speed of 1500-2000 rpm to obtain the isocyanate reactive component in the polyurethane composition as component A.

[0068] (2) Weigh the isocyanate component PM200 as component B and add it to the polyurethane-specific injection machine along with the component A obtained in step (1). Mix the materials and inject them into the resin tank through the polyurethane-specific injection machine to obtain the polyurethane resin matrix.

[0069] The preparation steps of the polyurethane resin matrix in Examples 2-4 and Comparative Examples 1-5 are the same as those in Example 1, except that the types and amounts of each component (by weight) are in accordance with the corresponding formulations shown in Tables 1-2.

[0070] The polyurethane resin matrices obtained in Examples 1 to 4 and Comparative Examples 1 to 5 were prepared into polyurethane pultruded composite profiles using a pultrusion process. The specific steps are as follows:

[0071] 105 glass fibers are drawn from the yarn rack, passed through the yarn threading plate, and entered the glue injection box of the glue injection machine. They then pass through the mold cavity and are tied to the traction belt. The traction belt is placed in the traction machine, and the traction device is turned on until all the glass fibers are pulled straight. After that, the traction device is turned off. The mold heating system is turned on, with three heating zones. The heating temperatures from the yarn inlet to the yarn outlet are 120℃, 200℃, and 220℃ respectively. The heating time is ≥1 hour to ensure that the mold is fully heated.

[0072] Subsequently, the glue injection machine is started, and the polyurethane resins prepared in Examples 1-4 and Comparative Examples 1-5 are injected into the glue injection box until the glass fiber is fully impregnated. Then, the traction device is turned on, and the resin-impregnated glass fiber is pulled forward at a running speed of 1.5 m / min. After passing through the heating zone and curing, it is removed from the mold and cut to obtain the desired composite material sheet product.

[0073] Table 1: Components of polyurethane resin matrix, their dosage, and profile properties

[0074]

[0075] Table 2. Components of the polyurethane resin matrix, their dosage, and profile properties.

[0076]

[0077]

[0078] In the table above, the amount of isocyanate component to be applied can be calculated using the given isocyanate index.

[0079] The above experimental results show that the polyurethane composition invented in this institute can achieve controllable viscosity during the injection process and stable and rapid pultrusion during the processing (composite profiles can be prepared under high-speed pultrusion conditions with a linear speed of 1.5 m / min).

[0080] During pultrusion, the real-time viscosity of the polyurethane resin affects its wetting rate on the fiber and the effective adsorption thickness of the resin layer on the fiber. This invention controls the content of low-viscosity primary alcohol in the isocyanate reactive component to be 1-10 wt%, resulting in a viscosity of 400 mPa·s to 700 mPa·s for the isocyanate reactive component at 25°C, and a real-time mixed viscosity η of the isocyanate component and the isocyanate reactive component at 25°C. tCompared to the time t required for the initial mixed viscosity η0 to increase by 100%, which satisfies 660s≥t≥200s, this can effectively control the reaction process between the components in the polyurethane composition, ensure the effective wetting of the fiber by the resin, and ultimately achieve excellent performance of the composite profile.

[0081] If the content of low-viscosity primary alcohol is too low, the resulting polyurethane composition resin will have poor viscosity reduction effect, a high initial viscosity, and poor fiber impregnation. Under rapid pultrusion, the fiber impregnation effect will further deteriorate, leading to processing problems in the composite profile. If the content of low-viscosity primary alcohol is too high, the polyurethane composition will react too quickly, and the resin will thicken too rapidly, resulting in a further shortening of the impregnation time during rapid pultrusion, making it impossible to guarantee effective fiber impregnation by the polyurethane resin. In addition, low-viscosity polyols are non-primary alcohols, and their resin viscosity reduction effect is also poor, with a high initial viscosity and poor fiber impregnation. Furthermore, if the amount of catalyst in the composition is not within the appropriate range, problems such as large fluctuations in resin extrusion and resin gelation will occur, leading to instability in the pultrusion process.

[0082] Table 3 Properties of composite profiles formed by polyurethane compositions and fibers

[0083] serial number Tensile strength / MPa Tensile modulus / GPa Bending strength / MPa Flexural modulus / GPa Comparative Example 1 1074 49.8 1203 41.4 Comparative Example 2 - - - - Comparative Example 3 987 48.1 1075 39.8 Comparative Example 4 977 47.3 1022 19.2 Comparative Example 5 - - - - Example 1 1389 52.9 1600 44.2 Example 2 1432 53.7 1612 44.8 Example 3 1405 53.1 1610 44.5 Example 4 1400 53.0 1603 44.3

[0084] The polyurethane resins prepared in the various embodiments exhibit good wetting effects on glass fibers, resulting in composite profiles with excellent mechanical properties. In contrast, the polyurethane resins prepared in the comparative examples show poor wetting effects on glass fibers and unstable pultrusion processing, leading to composite profiles with poor mechanical properties.

[0085] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the spirit of the invention.

Claims

1. A polyurethane composition comprising an isocyanate component and an isocyanate reactive component, characterized in that: (A) The viscosity of the isocyanate reactive component at 25°C is 400 mPa·s to 700 mPa·s; The isocyanate reactive component includes: component i), a low-viscosity polyol; the low-viscosity polyol has a viscosity of ≤200 mPa·s at 25°C, a hydroxyl value of ≥1000 mgKOH / g, and is a primary alcohol with an average functionality of ≥2. (B) Real-time mixing viscosity η of the isocyanate component and the isocyanate reactive component at 25°C t The time required for the initial mixed viscosity η0 to increase by 100% is t, which satisfies 660s≥t≥200s.

2. The polyurethane composition according to claim 1, characterized in that, The low-viscosity polyol is selected from one or more of ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,4-butanediol, 2-methylpropanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, and dipropylene glycol.

3. The polyurethane composition according to claim 1 or 2, characterized in that, The content of the low-viscosity polyol accounts for 1 wt% to 10 wt% of the total mass of the isocyanate reactive component.

4. The polyurethane composition according to any one of claims 1-3, characterized in that, The isocyanate reactive component further includes: component ii), which is selected from one or more of polyether polyols, polyester polyols, polyether carbonate polyols, polycarbonate polyols, and bio-based polyols, preferably selected from one or more of polyether polyols, polyester polyols, and bio-based polyols; The content of component ii) accounts for 90-99 wt% of the total mass of the isocyanate reactive components.

5. The polyurethane composition according to any one of claims 1-4, characterized in that, The polyurethane composition further includes a catalyst; The catalyst is an amine catalyst or an organometallic catalyst, preferably selected from one or more of the following: triethylamine, tributylamine, triethylenediamine, N-ethylmorpholine, N,N,N',N'-tetramethylethylenediamine, pentamethyldiethylenediamine, N,N-methylaniline, N,N-dimethylaniline, tin(II) acetate, tin(II) octoate, tin ethylhexanoate, tin laurate, dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate, dibutyltin maleate, and dioctyltin diacetate. The amount of catalyst used is 0 to 1 wt% of the total weight of the isocyanate reactive components, preferably 0.1 wt% to 1 wt%.

6. The polyurethane composition according to any one of claims 1-5, characterized in that, The isocyanate index of the polyurethane composition is 0.9 to 1.

3.

7. The polyurethane composition according to any one of claims 1-6, characterized in that, The isocyanate component is selected from toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, naphthalene diisocyanate, terephthalic diisocyanate, 1,4-cyclohexane diisocyanate, phenylenediamine diisocyanate, cyclohexane diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, tetramethyl-m-phenylenediamine diisocyanate, norbornene diisocyanate, dimethylbiphenyl diisocyanate, methylcyclohexyl diisocyanate, tetramethylene diisocyanate, 2-methylpentamethylene diisocyanate, dodecamethoxy The product comprises one or more of the following: hexamethylene diisocyanate, 4,4'-diisocyanate-3,3'-dimethyldicyclohexylmethane, 4,4'-diisocyanate-2,2-dicyclohexylpropane, poly(hexamethylene diisocyanate), octamethylene diisocyanate, toluene-α,4-diisocyanate, 2,4,6-trimethyl-1,3-phenylene diisocyanate, 4-chloro-6-methyl-1,3-phenylene diisocyanate, poly(tetrafluoroethylene oxide-co-difluoromethyleneoxy)α,ω-diisocyanate, 1,4-butane diisocyanate, 1,8-octane diisocyanate, and their isocyanate prepolymers and modified products.

8. The polyurethane composition according to any one of claims 1-7, characterized in that, The polyurethane composition further includes additives; The additives are selected from one or more of the following: internal release agents, flame retardants, fillers, pigments, antioxidants, foaming agents, stabilizers, light stabilizers, auxiliary antioxidants, hydrolytic stabilizers, bactericides and mildew inhibitors, defoamers, rheology modifiers, leveling agents, wetting agents, reactive diluents, coupling agents, color pastes, catalysts, dehydrating agents, and molecular sieves.

9. A polyurethane composite material, characterized in that, The composite material includes: (a) A polyurethane resin matrix, comprising 15 to 25 wt% of the total weight of the composite material, wherein the polyurethane resin matrix is ​​obtained by means of the polyurethane composition according to any one of claims 1-8; (b) A reinforcing material comprising 75 to 85 wt% of the total weight of the composite material; The reinforcing material is a fibrous material, preferably selected from at least one of glass fiber, carbon fiber, polyester fiber, natural fiber, nylon fiber, aromatic polyamide fiber, basalt fiber, boron fiber, silicon carbide fiber, asbestos fiber, whiskers and metal fiber.

10. The polyurethane composite material according to claim 9, characterized in that, The preparation process of the composite material is as follows: the polyurethane resin matrix and the reinforcing material are mixed evenly in proportion, and then processed and molded into a product; Preferably, during the processing and molding of the composite material, the isocyanate reactive component, catalyst, and optional additives, which are components A, are fully premixed with the isocyanate component, which is a component B. Preferably, the composite material is processed and formed by pultrusion molding.

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