Resin composition as well as preparation method and application thereof

Abstract

The invention relates to a resin composition as well as a preparation method and application thereof. The resin composition comprises mixed resin, an accelerant and curing agents, the mixed resin comprises epoxy resin and functional resin, the functional resin comprises polar groups with the dipole moment larger than 0.7, the mass fraction of the polar groups in the functional resin is 3%-15%, and the curing agents comprise a medium-temperature curing agent and a low-temperature curing agent. The resin composition can be rapidly cured at the temperature of 120 DEG C or below, meanwhile, a prepreg prepared from the resin composition is excellent in latency, and a composite material further prepared from the resin composition has excellent heat resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer composite materials, in particular to a resin composition and a preparation method and application thereof. Background Art

[0002] With the change of market demand and the expansion of composite material applications in various terminals, various forms of composite materials have emerged, such as composite materials covered with film materials on the surface, and the production process of composite materials has become more and more diversified. In order to improve the molding efficiency of composite materials, the integrated molding technology of composite materials and film materials is usually used to reduce the processing process. However, the temperature resistance of leather film materials is around 120℃, and the molding temperature of traditional composite materials is much higher than 120℃, which limits the integrated molding technology. In addition, the prepregs prepared at 120℃ have the defect of poor latency, and the composite materials prepared further also have the defect of poor heat resistance. Summary of the invention

[0003] Based on this, it is necessary to provide a resin composition and a preparation method and application thereof to address the above problems. The resin composition can be quickly cured below 120°C, and the prepreg prepared by the resin composition has excellent latent property, and the composite material further prepared has excellent heat resistance.

[0004] The invention discloses a resin composition, which comprises a mixed resin, an accelerator and a curing agent, wherein the mixed resin comprises an epoxy resin and a functional resin, the functional resin comprises a polar group with a dipole moment greater than 0.7, the mass fraction of the polar group in the functional resin is 3%-15%, and the curing agent comprises a medium-temperature curing agent and a low-temperature curing agent.

[0005] In one embodiment, the functional resin satisfies at least one of the following conditions:

[0006] (1) The mass ratio of the functional resin to the epoxy resin is 15:85-5:95;

[0007] (2) The epoxy equivalent of the functional resin is 100 g / eq-200 g / eq;

[0008] (3) The mass fraction of the polar group in the functional resin is 6%-10%;

[0009] (4) The polar group includes at least one of a carboxyl group, an alcoholic hydroxyl group, a phenolic hydroxyl group, a nitro group or an amine group.

[0010] In one embodiment, the functional resin includes at least one of polyester polyol, modified ethylene glycol epoxy resin, carboxyl functional acrylate resin, carboxyl-terminated nitrile rubber modified bisphenol A epoxy resin, rubber-epoxy prepolymer, epoxidized meta-xylylenediamine or tetrafunctional glycidylamine epoxy resin.

[0011] In one embodiment, the curing agent satisfies at least one of the following conditions:

[0012] (1) The medium temperature curing agent includes conjugated double bonds and cyano groups;

[0013] (2) The active hydrogen equivalent of the low temperature curing agent is 80 g / eq-150 g / eq;

[0014] (3) Calculated based on the active hydrogen equivalent, the ratio of the medium temperature curing agent to the low temperature curing agent is 3:7-1.4:8.6.

[0015] In one embodiment, the medium temperature curing agent includes at least one of dicyandiamide, Lewis acid-amine complex, modified urea, microcapsule curing agent, dihydrazine, 2,4,6-tris(dimethylaminomethyl)phenol or cyanobiphenol;

[0016] And / or, the low-temperature curing agent includes at least one of a polyvalent mixed amine, a polythiol, an imidazole adduct, a modified amine or a phenolic amine.

[0017] In one embodiment, the accelerator includes a basic group, and the basic group forms an amine group or an ether group after hydrolysis.

[0018] In one embodiment, based on 100 parts by weight of the mixed resin, the amount of the curing agent is 2 parts by weight to 24 parts by weight, and the amount of the accelerator is 0.05 parts by weight to 1 part by weight.

[0019] In one embodiment, the resin composition further comprises a stabilizer, and the stabilizer comprises at least one of boric acid, hypophosphorous acid or barbituric acid.

[0020] A prepreg comprises a reinforcing material and the dried resin composition as described above attached to the reinforcing material.

[0021] A composite material comprises a laminated film material and the cured prepreg as described above.

[0022] In the resin composition provided by the present invention, the mixed resin, the curing agent and the accelerator cooperate with each other, and the resin composition is applied to the process of preparing prepreg and composite materials. Firstly, the accelerator can make the low-temperature curing agent have strong nucleophilic ability, so that the epoxy functional group can be quickly opened, thereby quickly initiating the curing reaction; secondly, since the low-temperature curing agent reduces the activation energy of the ring opening of the epoxy functional group, the resin composition can be quickly cured under the condition of less than 120° C.; in addition, since the medium-temperature curing agent can not only improve the uniformity and stability of the curing reaction, but also improve the controllability of the curing reaction by sealing, passivation, etc., the prepreg prepared by the resin composition has excellent latent performance; thirdly, the functional resin with a specific structure can improve the solubility of the curing agent in the resin composition on the one hand, and on the other hand, the polar groups in the functional resin can participate in the curing reaction to improve the crosslinking density, thereby improving the crosslinking density of the resin composition, thereby making the prepared composite material have excellent heat resistance. DETAILED DESCRIPTION

[0023] For ease of understanding of the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific implementation methods or embodiments, and are not intended to limit the present invention. The optional scope of the term "and / or" used herein includes any one of two or more related listed items, and also includes any and all combinations of related listed items, and the combinations include any two related listed items, any more related listed items, or all related listed items.

[0025] The invention provides a resin composition, which comprises a mixed resin, an accelerator and a curing agent, wherein the mixed resin comprises an epoxy resin and a functional resin, the functional resin comprises a polar group with a dipole moment greater than 0.7, the mass fraction of the polar group in the functional resin is 3%-15%, and the curing agent comprises a medium-temperature curing agent and a low-temperature curing agent.

[0026] In the resin composition provided by the present invention, the mixed resin, curing agent and accelerator cooperate with each other, so that the resin composition can be quickly cured below 120° C. At the same time, the prepreg prepared by the resin composition has excellent latent property, and the composite material further prepared has excellent heat resistance. Furthermore, the composite material can also have excellent bonding and low shrinkage.

[0027] Specifically, the resin composition is applied in the process of preparing prepreg and composite materials:

[0028] First, the accelerator can make the low-temperature curing agent have stronger nucleophilic ability, so that the epoxy functional group can open the ring quickly, thereby quickly initiating the curing reaction.

[0029] In one embodiment, the promoter includes a basic group, and preferably, the basic group forms an amine group or an ether group after hydrolysis; specifically, the promoter includes but is not limited to at least one of imidazole, modified imidazole, modified urea, phenol, benzyldimethylamine or triethylamine.

[0030] In one embodiment, based on 100 parts by weight of the mixed resin, the amount of the accelerator is 0.05 parts by weight to 1 part by weight, including but not limited to 0.05 parts by weight, 0.1 parts by weight, 0.15 parts by weight, 0.2 parts by weight, 0.25 parts by weight, 0.3 parts by weight, 0.35 parts by weight, 0.4 parts by weight, 0.45 parts by weight, 0.5 parts by weight, 0.55 parts by weight, 0.6 parts by weight, 0.65 parts by weight, 0.7 parts by weight, 0.75 parts by weight, 0.8 parts by weight, 0.85 parts by weight, 0.9 parts by weight, 0.95 parts by weight or 1 part by weight.

[0031] Secondly, since the low-temperature curing agent reduces the activation energy of the ring opening of the epoxy group, the resin composition can be quickly cured at conditions below 120°C; in addition, since the medium-temperature curing agent can not only improve the uniformity and stability of the curing reaction, but also improve the controllability of the curing reaction through sealing, passivation, etc., the prepreg made from the resin composition has excellent latent properties.

[0032] It can be understood that the low temperature curing agent can promote the curing of epoxy resin at a lower temperature. In one embodiment, the low temperature curing agent includes active hydrogen, and the active hydrogen equivalent is 80g / eq-150g / eq, including but not limited to 80g / eq, 90g / eq, 100g / eq, 110g / eq, 120g / eq, 130g / eq, 140g / eq or 150g / eq. Specifically, the low temperature curing agent includes but is not limited to at least one of a polyvalent mixed amine, a modified amine, a polythiol or an imidazole adduct.

[0033] Compared with low-temperature curing agents, medium-temperature curing agents are stable at room temperature and quickly decompose into amine groups after heating. In one embodiment, the medium-temperature curing agent includes conjugated double bonds and cyano groups. Specifically, the medium-temperature curing agent includes but is not limited to at least one of dicyandiamide, Lewis acid-amine complex, modified urea, dihydrazine or 2,4,6-tris(dimethylaminomethyl)phenol or cyanodiphenol; further, when the medium-temperature curing agent is a microcapsule-type medium-temperature curing agent, it is beneficial to further improve the latent performance of the prepreg.

[0034] In one embodiment, based on 100 parts by weight of the mixed resin, the amount of the curing agent is 2 parts by weight to 24 parts by weight. Preferably, calculated on the basis of active hydrogen equivalent, the ratio of the medium temperature curing agent to the low temperature curing agent is 4:6-1.4:8.6, including but not limited to 4:6, 3.5:6.5, 3:7, 2.6:7.4, 2:8 or 1.4:8.6. Preferably, the ratio of the medium temperature curing agent to the low temperature curing agent is 3:7-1.4:8.6, thereby improving the curing rate of the resin composition and the latency of the prepreg. It should be noted that, calculated on the basis of active hydrogen equivalent, the ratio of the medium temperature curing agent to the low temperature curing agent refers to the ratio of the total amount of active hydrogen in the medium temperature curing agent to the total amount of active hydrogen in the low temperature curing agent.

[0035] Thirdly, the functional resin with a specific structure can improve the solubility of the curing agent in the resin composition on the one hand, and on the other hand, the polar groups in the functional resin can participate in the reaction to increase the crosslinking density, thereby increasing the crosslinking density of the resin composition, and thus making the prepared composite material have excellent heat resistance.

[0036] In one embodiment, the polar groups in the functional resin include at least one of a carboxyl group, an alcoholic hydroxyl group, a phenolic hydroxyl group, a nitro group or an amine group; specifically, the functional resin includes but is not limited to at least one of polyester polyols, modified ethylene glycol epoxy resins, carboxyl functional acrylate resins, carboxyl-terminated nitrile rubber modified bisphenol A epoxy resins, rubber-epoxy prepolymers, epoxidized meta-xylylenediamine or tetrafunctional glycidylamine epoxy resins.

[0037] In addition, the polar groups in the functional resin can not only participate in the curing reaction, but also improve the solubility of the curing agent in the resin composition, thereby increasing the crosslinking density. In addition, the lower epoxy equivalent of the functional resin can further increase the crosslinking density during the curing process. Therefore, adjusting the epoxy equivalent of the functional resin and the proportion of the polar groups at the same time can improve the interlayer bonding strength of the composite material and avoid high-temperature shrinkage of the composite material, so that the reinforcing material in the composite material can be selected from organic fibers, such as UPE materials, BPO materials, nylon materials, polyester materials , aramid material or PI material, etc. In one embodiment, the epoxy equivalent of the functional resin is 100g / eq-200g / eq, including but not limited to 100g / eq, 110g / eq, 120g / eq, 130g / eq, 140g / eq, 150g / eq, 160g / eq, 170g / eq, 180g / eq, 190g / eq or 200g / eq, and the mass fraction of the polar group in the functional resin is 6%-10%, including but not limited to 6%, 7%, 8%, 9% or 10%.

[0038] In one embodiment, the epoxy resin includes but is not limited to at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, glycidyl ether epoxy resin or glycidyl ester epoxy resin; preferably, the mass ratio of the functional resin to the epoxy resin is 15:85-5:95, including but not limited to 15:85, 12:88, 10:90 or 5:95, thereby simultaneously improving the curing rate of the resin composition and the heat resistance of the composite material.

[0039] In one embodiment, the resin composition also includes a stabilizer, which can provide a weakly acidic environment for the curing reaction. The ring-opening reaction of the epoxy functional group tends to open at the multi-substituted carbon atom to form a relatively stable intermediate product, thereby further improving the latency of the prepreg. Specifically, the stabilizer includes but is not limited to at least one of boric acid, hypophosphorous acid or barbituric acid. Preferably, based on 100 parts by weight of the mixed resin, the amount of the stabilizer is 0.002 parts by weight to 0.05 parts by weight, thereby improving the latency of the prepreg without affecting the curing rate.

[0040] The present invention also provides a method for preparing the resin composition as described above, comprising the following steps:

[0041] S101, mixing a solvent with an epoxy resin and a functional resin to obtain a first adhesive solution;

[0042] S102, adding a curing agent to the first adhesive solution to obtain a second adhesive solution;

[0043] S103, mixing the second glue solution with the accelerator to obtain a resin composition.

[0044] In step S101, in order to better disperse the curing agent in the resin composition, the epoxy resin and the functional resin composition are first diluted with a solvent. It should be noted that the boiling point of the solvent is lower than 120°C.

[0045] In step S102, in order to make the components in the resin composition interact better and form a more stable and uniform structure, thereby improving the latency of the prepreg and the heat resistance of the composite material, preferably, constant temperature stirring is performed after the step of adding the curing agent to the first glue solution. Constant temperature stirring can make the temperature evenly distributed, and the temperature of the constant temperature stirring is 15°C-25°C.

[0046] The present invention also provides a prepreg, comprising a reinforcing material and the dried resin composition as described above attached to the reinforcing material.

[0047] In one embodiment, the reinforcing material includes one or more of glass fiber, aramid, PBO material, PI material, UPE material, basalt and carbon fiber.

[0048] In one embodiment, the drying temperature is 90° C.-120° C., and the drying time is 2 min-5 min.

[0049] The present invention also provides a composite material, comprising a stacked film material and the cured prepreg as described above.

[0050] In one embodiment, the film material includes at least one of a PU film, a PE film, a PVC film, a silicone leather film, a PBO material, a PI material or a UPE material.

[0051] The composite material provided by the present invention not only has excellent heat resistance, but can also be prepared by one-piece molding technology, which greatly shortens the processing process. When the composite material is prepared by one-piece molding technology, the preparation method of the composite material includes the following steps:

[0052] Step S201, providing the prepreg and film material as described above;

[0053] Step S202, at least one prepreg is coated on one surface of the film material, and hot pressing is performed to obtain a composite material, and the hot pressing temperature is less than or equal to 120°C.

[0054] In step S202, since the resin composition provided by the present invention can be quickly cured at a temperature below 120°C, the temperature in the hot pressing step is preferably 80°C-120°C, and the time is preferably 5 min-30 min.

[0055] Hereinafter, the resin composition and its preparation method and application will be further described through the following specific examples.

[0056] Example 1

[0057] A butanone solvent is mixed with an epoxy resin and a functional resin, and stirred evenly to obtain a first adhesive solution; a curing agent is added to the first adhesive solution, and a second adhesive solution is obtained after constant temperature stirring at 25° C.; the second adhesive solution is stirred and mixed with a stabilizer for 2 hours to obtain a resin composition.

[0058] The type selection and proportion of each component in the resin composition are shown in Table 1.

[0059] Table 1

[0060]

[0061]

[0062] In Table 1, the amount of the medium temperature curing agent is 4.39 parts by weight, and the active hydrogen equivalent is 60 g / eq. The amount of the low temperature curing agent is 23.94 parts by weight, and the active hydrogen equivalent is 115 g / eq. Therefore, calculated by the active hydrogen equivalent, the ratio of the medium temperature curing agent to the low temperature curing agent is (4.39÷60):(23.94÷115)=2.6:7.4.

[0063] The obtained resin composition was uniformly impregnated onto the reinforcing material nylon, and the prepreg was obtained after baking at 105° C. for 3 minutes.

[0064] A film material PU is provided, three prepregs are covered on one surface of the film material, a release film is covered on the outer surface, and the film material is pressed at a temperature of 115° C. for 8 minutes to obtain a composite material.

[0065] Comparative Example 1

[0066] Comparative Example 1 was carried out with reference to Example 1, except that the resin composition did not include a medium-temperature curing agent, and the amount of the low-temperature curing agent was 32.35 parts by weight; during the preparation of the composite material, the pressing temperature was 100° C. and the time was 5 minutes.

[0067] Comparative Example 2

[0068] Comparative Example 2 was carried out with reference to Example 1, except that the resin composition did not include a low-temperature curing agent, and the amount of the medium-temperature curing agent was 16.88 parts by weight; during the preparation of the composite material, the pressing temperature was 120° C. and the time was 30 minutes.

[0069] Comparative Example 3

[0070] Comparative Example 3 is carried out with reference to Example 1, except that the resin composition does not include a functional resin, the weight of the epoxy resin is 100 parts, the amount of the medium-temperature curing agent is 3.28 parts by weight, and the amount of the low-temperature curing agent is 17.92 parts by weight; during the preparation of the composite material, the pressing temperature is 115°C and the time is 8 minutes.

[0071] Comparative Example 4

[0072] Comparative Example 4 is carried out with reference to Example 1, except that the functional resin in the resin composition is selected from unsaturated polyester resin (bisphenol A type unsaturated polyester resin), the unsaturated polyester resin includes a lipid group with a dipole moment of 0.6, the mass fraction of the lipid group in the functional resin is 13.5%, the amount of the medium temperature curing agent is 2.89 parts by weight, and the amount of the low temperature curing agent is 15.77 parts by weight. In the process of preparing the composite material, the pressing temperature is 115°C and the time is 8 minutes.

[0073] Comparative Example 5

[0074] Comparative Example 5 is carried out with reference to Example 1, except that the functional resin in the resin composition is selected from polyester polyol resin (polycarbonate polyol resin), the polyester polyol resin includes hydroxyl groups with a dipole moment of 1.67, the mass fraction of hydroxyl groups in the functional resin composition is 2%, the amount of the medium temperature curing agent is 2.89 parts by weight, and the amount of the low temperature curing agent is 15.77 parts by weight. In the process of preparing the composite material, the pressing temperature is 115°C and the time is 8 minutes.

[0075] Comparative Example 6

[0076] Comparative Example 6 is carried out with reference to Example 1, except that the functional resin in the resin composition is selected from polystyrene resin, the polystyrene resin includes styrene with a dipole moment of 0.63, the mass fraction of the polar group in the functional resin is 25.6%, the amount of the medium-temperature curing agent is 2.89 parts by weight, and the amount of the low-temperature curing agent is 15.77 parts by weight; in the process of preparing the composite material, the pressing temperature is 115°C and the time is 8 min.

[0077] Comparative Example 7

[0078] Comparative Example 7 was carried out with reference to Example 1, except that no accelerator was included in the resin composition, and during the preparation of the composite material, the pressing temperature was 120° C. and the pressing time was 30 min.

[0079] Test Example 1

[0080] The storage period of the prepregs prepared in Test Example 1 and Comparative Examples 1-7 is used to represent the latency of the prepregs. The shrinkage, heat resistance and bonding properties of the composite materials prepared in Test Example 1 and Comparative Examples 1-7 are shown in the following test methods and the test results are shown in Table 2.

[0081] Storage period: The test is to store the prepreg at room temperature and record the time required for the prepreg gel time to decay by 10%. Gel time test method: According to the standard - GBT12007-1989 epoxy resin gel time test method, the test condition is 120℃.

[0082] Shrinkage rate: prepreg and film materials of 10*10cm size are hot pressed into composite materials, and the dimensional change of the composite materials is observed, that is, shrinkage rate = (area before hot pressing - area after hot pressing) / area before hot pressing.

[0083] Heat resistance: The composite material is made into a 90° special-shaped piece, boiled in 100°C boiling water for 30 minutes, and then the special-shaped piece is observed to see if it is deformed. The angle of the special-shaped piece after boiling is recorded as α, and the deformation angle Δα=α-90°.

[0084] Bonding: Cut the composite material into 2mm wide strips, use a universal tensile machine to stretch the die to clamp the upper and lower sides of the strips, and test the average stress of 5cm peeling off the upper and lower sides at a speed of 50mm / min, which is the bonding.

[0085] Table 2

[0086]

[0087]

[0088] Example 2

[0089] Example 2 is carried out with reference to Example 1, except that the functional resin is selected from epoxidized meta-phenylenediamine resin, wherein the epoxidized meta-phenylenediamine resin contains an amine group with a dipole moment of 1.46, the mass fraction of the amine group in the functional resin is 7.8%, the epoxy equivalent is 110 g / eq, the epoxy resin is selected from bisphenol F epoxy resin, the amount of the medium temperature curing agent is 9.77 parts by weight, and the amount of the low temperature curing agent is 53.34 parts by weight. Therefore, calculated by active hydrogen equivalent, the ratio of the medium temperature curing agent to the low temperature curing agent is 2.6:7.4.

[0090] Example 3

[0091] Example 3 is carried out with reference to Example 1, except that the functional resin is selected from carboxyl functional acrylate resin, wherein the carboxyl functional acrylate resin contains a polar group carboxyl with a dipole moment of 7.5, and the mass fraction of the carboxyl group in the functional resin is 13.5%, the epoxy resin is selected from bisphenol F epoxy resin, the amount of the medium temperature curing agent is 8.58 parts by weight, and the amount of the low temperature curing agent is 46.81 parts by weight. Therefore, calculated on the basis of active hydrogen equivalent, the ratio of the medium temperature curing agent to the low temperature curing agent is 2.6:7.4.

[0092] Example 4

[0093] Example 4 is carried out with reference to Example 1, except that the functional resin is selected from terminal carboxyl nitrile rubber modified bisphenol A resin, wherein the terminal carboxyl nitrile rubber modified bisphenol A resin contains a polar group carboxyl with a dipole moment of 7.5, the mass fraction of the carboxyl group in the functional resin is 12%, the epoxy equivalent is 200g / eq, the epoxy resin is selected from bisphenol F epoxy resin, the amount of medium temperature curing agent is 9 parts by weight, and the amount of low temperature curing agent is 49.16 parts by weight. Therefore, calculated by active hydrogen equivalent, the ratio of the medium temperature curing agent to the low temperature curing agent is 2.6:7.4.

[0094] Example 5

[0095] Example 5 is carried out with reference to Example 1, except that the functional resin is selected from polycarbonate diol resin, wherein the polycarbonate diol resin contains a hydroxyl group with a dipole moment of 1.67, and the mass fraction of the hydroxyl group in the functional resin is 3.1%, the epoxy resin is selected from bisphenol F epoxy resin, the amount of the medium temperature curing agent is 8.08 parts by weight, and the amount of the low temperature curing agent is 44.05 parts by weight. Therefore, calculated on the basis of active hydrogen equivalent, the ratio of the medium temperature curing agent to the low temperature curing agent is 2.6:7.4.

[0096] Example 6

[0097] Example 6 is carried out with reference to Example 1, except that the amount of functional resin is 15 parts by weight, the amount of epoxy resin is 85 parts by weight, the epoxy resin is selected from glycidyl ether epoxy resin, the amount of medium temperature curing agent is 8.85 parts by weight, and the amount of low temperature curing agent is 48.28 parts by weight. Therefore, calculated on the basis of active hydrogen equivalent, the ratio of medium temperature curing agent to the low temperature curing agent is 2.6:7.4.

[0098] Example 7

[0099] Example 7 is carried out with reference to Example 1, except that the amount of the functional resin is 5 parts by weight, the amount of the epoxy resin is 95 parts by weight, the epoxy resin is selected from glycidyl ether epoxy resin, the amount of the medium temperature curing agent is 8.42 parts by weight, and the amount of the low temperature curing agent is 45.95 parts by weight. Therefore, calculated on the basis of active hydrogen equivalent, the ratio of the medium temperature curing agent to the low temperature curing agent is 2.6:7.4.

[0100] Test Example 2

[0101] Referring to Test Example 1, the storage period of the prepregs prepared in Examples 2-7 was tested, and the shrinkage, heat resistance and bonding properties of the composite materials prepared in Examples 2-7 were tested. The test results are shown in Table 3.

[0102] Table 3

[0103]

[0104]

[0105] Example 8

[0106] Example 8 is carried out with reference to Example 1, except that the low-temperature curing agent is selected from imidazole adduct curing agent PN-31, the active hydrogen equivalent is 95 g / eq, the amount of medium-temperature curing agent is 4.39 parts by weight, and the amount of low-temperature curing agent is 19.77 parts by weight. Therefore, calculated by active hydrogen equivalent, the ratio of the medium-temperature curing agent to the low-temperature curing agent is 2.6:7.4.

[0107] Example 9

[0108] Example 9 is carried out with reference to Example 1, except that the low-temperature curing agent is selected from a polythiol curing agent, the active hydrogen equivalent is 285 g / eq, the amount of the medium-temperature curing agent is 4.39 parts by weight, and the amount of the low-temperature curing agent is 59.32 parts by weight. Therefore, calculated by active hydrogen equivalent, the ratio of the medium-temperature curing agent to the low-temperature curing agent is 2.6:7.4.

[0109] Example 10

[0110] Example 10 is carried out with reference to Example 1, except that the medium temperature curing agent is selected from dicyandiamide curing agent (dichlorodiamine), the active hydrogen equivalent is 21 g / eq, the amount of the medium temperature curing agent is 1.54 parts by weight, and the amount of the low temperature curing agent is 23.94 parts by weight. Therefore, calculated by active hydrogen equivalent, the ratio of the medium temperature curing agent to the low temperature curing agent is 2.6:7.4.

[0111] Embodiment 11

[0112] Example 11 is carried out with reference to Example 1, except that the amount of the medium-temperature curing agent is 5.91 parts by weight, and the amount of the low-temperature curing agent is 21.02 parts by weight. Therefore, calculated on the basis of active hydrogen equivalent, the ratio of the medium-temperature curing agent to the low-temperature curing agent is 3.5:6.5.

[0113] Example 12

[0114] Example 12 is carried out with reference to Example 1, except that the medium temperature curing agent is selected from 2,4,6-tris(dimethylaminomethyl)phenol, with an active hydrogen equivalent of 61 g / eq, and the amount used is 3.94 parts by weight; the low temperature curing agent is a mixed amine curing agent Versami d@150, with an active hydrogen equivalent of 103 g / eq, and the amount used is 18.83 parts by weight; the ratio of the medium temperature curing agent to the low temperature curing agent is 3.5:6.5.

[0115] Test Example 3

[0116] Referring to Test Example 1, the storage period of the prepregs prepared in Examples 8-12 was tested, and the shrinkage, heat resistance and bonding properties of the composite materials prepared in Examples 8-12 were tested. The test results are shown in Table 4.

[0117] Table 4

[0118] Storage period (days) Shrinkage rate (%) Heat resistance(°) Binding (N) Example 8 20 1.1 1.7 23 Example 9 8 2.1 3.5 37 Example 10 13 0.7 0.7 36 Embodiment 11 17 1.1 2.5 25 Example 12 16 1.5 2.3 23

[0119] Example 13

[0120] Example 13 is carried out with reference to Example 1, except that the promoter is selected from phenol, and the amount of phenol used is 0.4 parts by weight.

[0121] Embodiment 14

[0122] Example 14 is carried out with reference to Example 1, except that a stabilizer is added simultaneously with the addition of the accelerator, the stabilizer is selected from barbituric acid, and the amount of barbituric acid used is 0.03 parts by weight.

[0123] Test Example 4

[0124] Referring to Test Example 1, the storage period of the prepregs prepared in Examples 13-14 was tested, and the shrinkage, heat resistance and bonding properties of the composite materials prepared in Examples 13-14 were tested. The test results are shown in Table 5.

[0125] Table 5

[0126] Storage period (days) Shrinkage rate (%) Heat resistance(°) Binding (N) Example 13 13 1.1 0.5 33 Embodiment 14 25.0 0.9 0.5 34

[0127] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0128] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A resin composition, characterized in that The resin composition includes a mixed resin, an accelerator and a curing agent, wherein the mixed resin includes an epoxy resin and a functional resin, the functional resin includes a polar group with a dipole moment greater than 0.7, the mass fraction of the polar group in the functional resin is 3%-15%, and the curing agent includes a medium-temperature curing agent and a low-temperature curing agent.

2. The resin composition according to claim 1, characterized in that The functional resin meets at least one of the following conditions: (1) The mass ratio of the functional resin to the epoxy resin is 15:85-5:95; (2) The epoxy equivalent of the functional resin is 100 g / eq-200 g / eq; (3) The mass fraction of the polar group in the functional resin is 6%-10%; (4) The polar group includes at least one of a carboxyl group, an alcoholic hydroxyl group, a phenolic hydroxyl group, a nitro group or an amine group.

3. The resin composition according to claim 2, characterized in that The functional resin includes at least one of polyester polyol, modified ethylene glycol epoxy resin, carboxyl functional acrylate resin, carboxyl-terminated nitrile rubber modified bisphenol A epoxy resin, rubber-epoxy prepolymer, epoxidized meta-xylylenediamine or tetrafunctional glycidylamine epoxy resin.

4. The resin composition according to claim 1, characterized in that The curing agent meets at least one of the following conditions: (1) The medium temperature curing agent includes conjugated double bonds and cyano groups; (2) The active hydrogen equivalent of the low temperature curing agent is 80 g / eq-150 g / eq; (3) Calculated based on the active hydrogen equivalent, the ratio of the medium temperature curing agent to the low temperature curing agent is 3:7-1.4:8.

6.

5. The resin composition according to claim 4, characterized in that The medium temperature curing agent includes at least one of dicyandiamide, Lewis acid-amine complex, modified urea, dihydrazine, 2,4,6-tris(dimethylaminomethyl)phenol or cyanobiphenol; And / or, the low temperature curing agent includes at least one of a polyvalent mixed amine, a polythiol, an imidazole adduct, a modified amine or a phenalkamine.

6. The resin composition according to any one of claims 1 to 5, characterized in that The accelerator includes a basic group, and the basic group forms an amine group or an ether group after hydrolysis.

7. The resin composition according to any one of claims 1 to 5, characterized in that Based on 100 parts by weight of the mixed resin, the amount of the curing agent is 2 parts by weight to 24 parts by weight, and the amount of the accelerator is 0.05 parts by weight to 1 part by weight.

8. The resin composition according to any one of claims 1 to 5, characterized in that The resin composition also includes a stabilizer, and the stabilizer includes at least one of boric acid, hypophosphorous acid or barbituric acid.

9. A prepreg, characterized in that: The invention comprises a reinforcing material and a dried resin composition according to any one of claims 1 to 8 attached to the reinforcing material.

10. A composite material, characterized in that: The composite material comprises a laminated film material and the cured prepreg according to claim 9.

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