Epoxy resin and polymer composite material

Abstract

FIELD: polymer composite materials.SUBSTANCE: epoxy binder is proposed for producing a polymer composite material, comprising an epoxy resin, an active diluent for epoxy resins and a curing system, wherein the epoxy resin is a liquid epoxy resin based on Bisphenol A with an epoxy group content of 180 to 200 g / eq, and the curing system is dicyandiamide, isophoronediamine and a mixture of polyoxypropylenediamines; in addition, the epoxy binder includes an elasticizing additive – low molecular weight butadiene rubber with acrylic acid nitrile and an adhesive additive – 3-glycidoxytrimethoxysilane in the following quantities, wt.%: Bisphenol A based epoxy resin 55-63, active diluent for epoxy resins 15.5-19.3, dicyandiamide 0.06-0.4, isophoronediamine 5.5-8.0, polyoxypropylene diamine mixture 15.0-19.0, 3-glycidoxytrimethoxysilane 0.3-1.5, the rest is elasticizing additive. A polymer composite material is also proposed. The group of inventions provides a reduction in the initial viscosity values at a temperature of 21±3 °C within 0.09-0.3 Pa s and viscosity retention in the range of 150-210 min at a temperature of 21±3 °C to 1 Pa s, i.e. the technological viability is at least 2.5 hours, achieving tensile strength values of up to 90 MPa, elongation at break up to 7.5%, static bending strength up to 130 MPa, obtaining glass transition temperatures of cured samples in the range from 71°C to 80 °C, increased adhesion between the matrix and the fibre filler, increased tensile strength of carbon fibre up to 5.0 GPa, reduced curing time to 5 days at a temperature of 21±3 °C, the possibility of accelerated curing at a temperature of 70 °C at a curing degree of over 96% for 6 hours.EFFECT: improved performance.2 cl, 1 dwg, 2 tbl, 5 ex

Description

[0001] The invention relates to the field of polymer composite materials (PCM) based on epoxy binders and carbon fiber fillers, manufactured by continuous winding and vacuum infusion for the production of PCM products for the energy, construction, aviation, mechanical engineering, shipbuilding industries and in other areas of technology.

[0002] A cold-curing epoxy binder for producing adhesives, filling, sealing, and repair compounds is known from the prior art (RU 2749380 C2, 12.05.2020). The epoxy binder contains:

[0003] - epoxy resin grade ED-20, or epoxy resin grade EA in the amount of 100 mass parts;

[0004] - as a hardener, polyamide resin PO-300 in the amount of 50.5-108.0 mass, h.;

[0005] - accelerator UP 606 / 2 in the amount of 3.33-4.96 mass, h.;

[0006] - low molecular weight rubber of the PPG-2000-3A brand in an amount of 10-40 mass parts, where epoxy urethane rubber is characterized by a content of free epoxy groups of 3.3-3.7%.

[0007] The invention relates to frost-resistant cold-curing epoxy adhesive compositions with increased strength and deformation properties, ensuring the operability of adhesive joints in a wide range of operating temperatures, including in the extreme conditions of the Arctic and the Far North.

[0008] The main disadvantage of this epoxy binder is its high initial viscosity and short viscosity retention time at room temperature, which makes it impossible to process it into polymer composite materials using the winding method. This is due to the fact that this binder contains a viscous hardener of the PO-300 brand and rubber of the PPG-2000-3A brand in an amount of 10-40 parts by weight. Their presence in the system leads to the fact that even with the use of low-viscosity resin of the EA brand, it is impossible to obtain a binder with an initial viscosity of less than 0.3 Pa, and the presence of the accelerator UP 606 / 2 in an amount of 3.33-4.96 parts by weight leads to a rapid increase in viscosity. In addition, the tensile strength (at a test temperature of 20°C) does not exceed 40.5 MPa.

[0009] A cold-curing epoxy composition is known (RU 2479601 C2, 20.04.2013), containing an epoxy base including an epoxy diane resin with a molecular weight of 340 to 540, an epoxy urethane resin and a curing system containing an aromatic amine and a heterocyclic imidazole compound.

[0010] The invention relates to the creation of two-component cold-curing epoxy compositions for the production of prepregs, which can be used in construction, as well as in aviation, mechanical engineering, shipbuilding, and other fields of engineering. The proposed epoxy composition can be used as impregnating and adhesive compositions and for protective coatings of metal and concrete surfaces.

[0011] A disadvantage of the invention is the high viscosity of the binder, ranging from 5-7 Pa s, and the composition's process life of approximately 2 hours, which precludes its use in lengthy manufacturing processes for polymer composite materials using the winding method. Furthermore, the tensile strength of this composition does not exceed 60 MPa.

[0012] A known epoxy composition (EP 2180012 A1, April 28, 2010) is based on epoxy resins and dicyandiamide dissolved in a mixture of amine hardeners. The combination of dicyandiamide and amines increases the curing rate compared to pure amine. The dicyandiamide solution is stable during storage and is fully compatible with epoxy resins. These compositions are particularly suitable for continuous winding and for impregnating fiberglass-reinforced fabrics and natural fibers.

[0013] The proposed composition described in this invention comprises:

[0014] 1. 100 parts by weight of liquid epoxy resin or epoxy resin mixture;

[0015] 2. from 10 to 90 parts by weight of a hardener (per 100 parts by weight of epoxy resin), which contains 50 parts by weight of an amine and from 0.2 to 15 parts by weight of dicyandiamide, in which the amine is selected from diaminocyclohexane, isophoronediamine, diethyltriamine, aminoethylpiperazine and / or a polyetherpolyamine, such as commercially available Jeffamine D-230 and Jeffamine T-403 or a mixture of the above amines.

[0016] Disadvantages of the invention include compositions with a dicyandiamide content of 5.0 wt.% or more for the epoxy resin - isophoronediamine or Jeffamine D-230 system, since the use of a large excess of dicyandiamide leads to a violation of the stoichiometric ratio due to the occurrence of a competing polymerization-type reaction and, as a result, unreacted amino groups remain in the cured matrix.

[0017] Furthermore, the introduction of excess dicyandiamide leads to a sharp increase in reactivity. For example, the time to reach a viscosity of 100 mPa⋅s for a system with a 5 wt.% dicyandiamide content, compared to the original composition, is reduced by 3.3 times, and for 10 wt.%, by 6.2 times. However, during the curing process, the effectiveness of the accelerator decreases, and the time to reach a viscosity of 10,000 mPa⋅s for a system with a 5 wt.% dicyandiamide content, compared to the original composition, is reduced by 1.9 times, and for 10 wt.%, by 1.1 times. Such a sharp increase in reactivity at the beginning, especially for epoxy binders containing epoxy resins with a higher content of epoxy groups, can lead to the destruction or warping of the PCM product due to the occurrence of exothermic reactions accompanied by high values ​​of thermal effects.

[0018] The disadvantages of the invention include the absence of components in the invention that improve mechanical characteristics, since epoxy compositions are characterized by low impact resistance.

[0019] An epoxy composition is known (RU 2606443 C1, 10.01.2017) containing an epoxy resin or a mixture of resins (including an epoxy diane resin with a molecular weight of 340 to 430), an active diluent (aromatic glycidyl ether) and a curing system based on a mixture of amine hardeners (in a ratio of polyetheramine 10-40 wt.%; isophoronediamine 60-90 wt.%).

[0020] Based on the studies of the epoxy binder developed at the Kurchatov Institute National Research Center - VIAM, it was found that in order to obtain the stated mechanical and heat-resistant characteristics (static bending strength of 117-145 MPa, tensile strength of 80-85 MPa, glass transition temperature from 101 to 110°C), it is necessary to carry out an additional technological stage - post-curing for at least 3 hours at a temperature of 120°C. In addition, the disadvantages of the claimed invention include the high viscosity of the original system (more than 0.45 Pa⋅s), the low viscosity retention time (no more than 2 hours until the viscosity reaches 1 Pa⋅s), and the long time (up to 24 hours) required for complete shaping and obtaining a hard, non-stick surface of the PCM product, which allows it to be removed from the technological equipment and undergo the curing process in a dry-heat oven.

[0021] The closest technical solution in terms of the set of essential features and the achieved technical result (RU 2688608 C1, 05 / 21 / 2019), adopted as a prototype, is a two-component epoxy composition containing in its composition:

[0022] Epoxy diane resin with an epoxy group weight from 180 to 270 g / eq -35.0-90.0 mass.parts;

[0023] Plasticizing additive - 2.0-16.0, selected from aliphatic resins of diethylene glycol diglycidyl ether, triethylene glycol, 1,4-butanediol diglycidyl ether and dibutyl phthalate;

[0024] Thixotropic additive - 4.0-10.0 mass.h, selected from the group consisting of aerosil, polyurea, garamite;

[0025] A curing system that includes an adduct based on cycloaliphatic polyamines - 5.0-50.0 mass parts and polyoxyamine - 5.0-20.0 mass parts.

[0026] In this case, the ratio of the epoxy part to the curing system is 100:(30-65) parts by weight, respectively. The invention can be used to create polymer composite materials used in the construction industry, in external reinforcement systems for strengthening and repairing structures.

[0027] The disadvantages of the prototype include:

[0028] - high initial viscosity from 2 to 300 Pa s and low process life at room temperature - 100 min. One of the main requirements for binders used in injection technologies or winding methods is a low initial viscosity and a long viscosity retention time (up to 3-6 hours) at an impregnation temperature of up to 1.0 Pa s. This is necessary so that the reinforcing fiber filler, especially in the case of manufacturing a large-sized product, can be completely impregnated before the binder becomes too viscous to satisfactorily pass through the fibers (for uniform impregnation of the entire fiber volume);

[0029] - long-term curing (up to 7 days at 21°C). This long-term curing does not allow prepregs based on this curing regime to be used for quick solutions to man-made problems in the repair of building structures;

[0030] - uses dibutyl phthalate, an inert organic component, as a plasticizer. Dibutyl phthalate reacts poorly with epoxy resin, and to ensure their interaction, the epoxy resins must be maintained at 60°C with vigorous stirring for 2-3 hours. In this invention, the reaction system was not heated, and stirring was carried out at 200-800 rpm for at least 60 minutes, which prevented the complete incorporation of dibutyl phthalate into the system.

[0031] - To increase the thixotropic and adhesive properties, the authors use mineral fillers in quantities of 4.0-10.0 parts by weight, specifically Aerosil A 300, Aerosil A 380, Garamite 7305, and polyurea. According to the authors, increasing adhesion at the interface between the reinforcing filler and the epoxy binder significantly increases the tensile strength of the carbon fiber composite. However, these components are chemically only rheological (thixotropic) additives and cannot increase adhesion at the epoxy matrix-carbon fiber interface. Furthermore, the use of 4 parts by weight or more of mineral fillers does not allow this binder to be processed using injection technology or winding. Also, a binder with a higher thixotropy index will be worse at impregnating the monofilaments in the bundle of reinforcing filler threads and wetting cracks or defects on the surface of the concrete coating;

[0032] - The developed binder can only be processed by contact molding. It should be noted that polymer composite parts produced by this method have unstable characteristics, primarily due to the uncontrolled binder content, which leads to the non-reproducibility of the physical and mechanical properties of serial products. During contact molding of prepregs, deformation of the carbon fibers often occurs due to excessive intrusion of the binder into the dry areas between the fibers when it is rolled with a roller over the surface of the reinforcing filler. Furthermore, the quality of polymer composite parts will be highly dependent on the qualifications of the personnel, and the cost of the product will be higher, as this method requires increased binder consumption and the generation of greater waste in the form of plastic scraps, resin residues in the container for mixing with the hardener, and solvents after washing the rollers and brushes, compared to other non-autoclave processing methods.

[0033] - One of the main drawbacks of this invention is the significant deviation from the stoichiometric ratio of reactive resin / hardener groups for most of the examples given (from 5 to 60%), which consists of a significant excess of epoxy groups over amine groups. Therefore, the cured polymer matrix will have a more sparsely crosslinked three-dimensional network containing regions with unreacted oxirane groups, which leads not only to a decrease in strength and heat resistance but also to a deterioration in the performance of the polymer composite product.

[0034] The objective of this invention is to develop an epoxy binder having improved properties and to create a polymer composite material based on an epoxy binder and carbon fiber filler by continuous winding and vacuum infusion, having improved physical, mechanical and rheological properties, as well as improved adhesive characteristics.

[0035] The technical result of the claimed invention is a decrease in the initial viscosity of the binder at a temperature of 21±3°C to values ​​of 0.09-0.3 Pa s and maintaining the viscosity in the range of 150-210 min at a temperature of 21±3°C to 1 Pa s, i.e., the technological viability is at least 2.5 hours, achieving tensile strength values ​​of up to 90 MPa, elongation at break of up to 7.5%, static bending strength of up to 130 MPa, obtaining glass transition temperatures of cured samples in the range from 71 to 80°C, increasing the adhesion between the matrix and the fibrous filler. At the same time, the invention is aimed at achieving a technical result for carbon fiber reinforced plastics, namely, increasing the strength of carbon fiber reinforced plastic under fiber tension to 5.0 GPa, reducing the curing time to 5 days at a temperature of 21±3°C, as well as the possibility of accelerated curing at a temperature of 70°C for 6 hours with a degree of curing of more than 96%.

[0036] To achieve the set technical result, an epoxy binder is proposed, containing a liquid epoxy resin based on bisphenol A with an epoxy group content of 180 to 200 g / eq, an active diluent for epoxy resins, an elasticizing additive rubber low molecular weight copolymer of butadiene with acrylic acid nitrile, dicyandiamide, isophorone diamine, and a mixture of polyoxypropylene diamines were used as a curing system, an adhesive additive 3-glycidoxytrimethoxysilane in the following quantities, mass %:

[0037] Bisphenol A epoxy resin 55-63 active diluent for epoxy resins 15,5-19,3 dicyandiamide 0,06-0,4 isophoronediamine 5,5-8,0 mixture of polyoxypropylenediamines 15,0-19,0 3-Glycidoxytrimethoxysilane 0,3-1,5 elasticizing additive rest

[0038] Typically, to create a polymer composite, reinforcing fibers are impregnated with an epoxy binder. Reinforcing fibers for the fiber composite of the present invention may include conventional fibers used for reinforcing materials. Suitable reinforcing fibers include carbon filler in the form of a carbon fiber tow, such as SYT49(S)-12K and UMT49S-12K.

[0039] Also proposed is a PCM comprising an epoxy binder according to the present invention and a carbon fiber filler in the following component ratios by weight %:

[0040] epoxy binder 31-37 carbon fiber filler 63-69

[0041] The polymer composite material is produced by a continuous winding method according to the present invention. Description of the drawings.

[0042] Fig. 1 - microstructure of carbon fiber reinforced plastic samples manufactured without adding 3-glycidoxytrimethoxysilane to the epoxy binder (a); and with the addition of 3-glycidoxytrimethoxysilane (b).

[0043] To ensure high mechanical properties of polymer composite parts manufactured by continuous winding and / or vacuum infusion, the binder must have a sufficiently low viscosity (less than 0.3 Pa s), a long pot life (at least 2.5 hours), and be capable of ensuring effective impregnation of the fiber filler, even in geometrically complex shapes, throughout the entire process cycle. The epoxy binder cures to a conversion of over 96% at a temperature of 21±3°C for 5 days.

[0044] An accelerated curing mode for the binder has been developed, allowing it to cure at 70°C for 6 hours without significant thermal generation, which could cause thermal degradation and defects in the composite material. This accelerated curing is achieved by adding a small amount of dicyandiamide, which accelerates the curing of epoxy resins under the influence of a mixture of hardeners (cycloaliphatic amine and a mixture of polyoxypropylenediamines) experimentally selected in the calculated quantities. Furthermore, when developing the polymer binder for non-autoclave molding methods, solvents were not used. Instead, various active diluents and low-viscosity hardeners were employed, ensuring the necessary technological and operational characteristics.

[0045] In addition, when developing a thermosetting epoxy binder, only low-viscosity epoxy resin based on Bisphenol A with a narrower content of epoxy groups from 180 to 200 g / eq. of the ED-22 brand (GOST 10587-84 viscosity 7-12 Pas), DER-330 (Olin, USA), EP C YD 127 (Sinopec Beling Petrochemical Co / Ltd China), YD 127 (KUKDO, Korea), etc. were used in an amount of 55.0 to 63 wt. % of the total weight of the components, compared with the possibility of using more viscous resin analogs with a wider content of epoxy groups from 180 to 270 g / eq. in the prototype. ED-20 grade (GOST 10587-84, viscosity 13-20 Pa s) and DER-331. Increasing the proportion of Bisphenol A-based epoxy resin above 63.0% will lead to a critical increase in the binder's viscosity, making it unsuitable for processing. Conversely, reducing the proportion of Bisphenol A-based epoxy resin below 55.0% will result in a decrease in the glass transition temperature and strength properties.

[0046] To adjust the viscosity of the binder, active diluents are added, for example, UP-616, UP-624, DGEBD (diglycidyl ether of 1,4-butanediol), etc., or a mixture thereof in an amount of 15.5 to 19.3 wt. % of the total weight of the components. The use of low-molecular resins in the specified ratio allows not only to further reduce the viscosity of the binder, but also to increase the crosslinking density and increase the elasticity (elongation) of the cured epoxy matrix while maintaining high strength. Increasing the content of active diluents above 19.3 wt. % will lead to a significant increase in the elasticity of the polymer matrix and, as a result, to a decrease in the strength index and glass transition temperature. The content of active diluents is less than 9.0 wt. % will lead to an increase in the initial viscosity above 1 Pa-s, which will not allow the use of this binder in injection technologies or its processing by the continuous winding method.

[0047] To reduce brittleness and increase the elongation of the polymer matrix, low-molecular-weight oligomeric acrylonitrile-butadiene rubbers containing terminal end groups (so-called CTBN) were additionally introduced into the binder composition, for example, grades SKN-10 KTR, SKN-30 KTRA, and others, in quantities of up to 3.0 wt.%. The limited solubility of the rubber leads to its separation into a separate phase during curing and, accordingly, to the formation of particles in the matrix that absorb the fracture energy during crack growth. Increasing the rubber content above 3.0 wt.% will lead to a significant increase in viscosity and a decrease in strength and heat resistance.

[0048] To obtain a binder with a low viscosity increase rate and a long pot life of at least 2.5 hours, as well as the ability to cure for 5 days with a conversion rate of at least 96%, a mixture of different types of hardeners was used, unlike the prototype.

[0049] The addition of a mixture of moderately reactive polyoxypropylenediamines, such as Jeffamine D-230, Jeffamine D-400, or Jeffamine T-403, among others, in amounts ranging from 15.0 to 19.0 wt.% ensures a long pot life of the epoxy composition at room temperature. Furthermore, the incorporation of flexible polyetheramine fragments into the polymer chain increases elasticity, and the presence of additional amino groups in the Jeffamine T-403 molecule provides additional three-dimensional crosslinking of the polymer matrix, which increases its strength.

[0050]

[0051] The combined use of the low-viscosity cycloaliphatic hardener isophoronediamine in amounts up to 8.0 wt.% along with polyoxypropylenediamines and active diluents allows, firstly, to achieve a low initial viscosity of the binder. Secondly, the introduction of isophoronediamine, which contains an alkyl-substituted cyclohexane ring with amino groups with higher reactivity for the cis- and trans-configuration, makes it possible to regulate the pot life of the epoxy composition, as well as to ensure higher heat-resistant and strength properties compared to straight-chain aliphatic amines.

[0052] Brand names of isophoronediamine, such as: Vestamin IPD, Polypox IPD or Luxam IPD, etc.

[0053]

[0054] Dicyandiamide was additionally added to the composition in an amount of 0.06 to 0.4% by weight. Firstly, it was used as a crosslinking agent between the epoxy resin and rubber. Secondly, it was used as an accelerator for the curing reaction of epoxy resins under the action of a mixture of isophoronediamine / polyoxypropylenediamine hardeners. Its use reduced the curing time of the composition without significant thermal release and ensured low shrinkage during curing. Furthermore, epoxy systems cured with dicyandiamide exhibit high impact resistance, strong adhesion to substrates, good moisture resistance, and resistance to chemicals. Micronized powders were used as dicyandiamide, for example, Dyhard 100S (manufactured by Alzchem), Ducure 10 (manufactured by Feiming Chemical Limited), etc.

[0055] Thus, in the claimed epoxy composition, the composition and quantity of the hardener components were experimentally determined to maintain the stoichiometric ratio of epoxy and amine groups or to provide a slight excess of the latter. The presence of various types of amine / dicyandiamide hardener in the binder mixture leads to two types of curing: the primary polycondensation mechanism (which ensures the appearance of flexible chain sections in the cured matrix due to cycloaliphatic or polyetheramine fragments incorporated into the polymer chain) and the polymerization mechanism (which forms homopolymerization sites of epoxy resins, as well as sites where epoxy oligomers are cross-linked with acrylic onitrile-butadiene rubber). This combination of curing mechanisms ensures the formation of a more tightly cross-linked polymer matrix, and the presence of various fragments (flexible and rigid) in the microstructure provides higher strength characteristics.

[0056] To achieve high strength characteristics and ensure long-term service life of polymer composite materials, good adhesion and wettability of the reinforcing fibers are essential to maximize the interaction between the epoxy matrix and the fibers. To enhance adhesion, 3-glycidoxytrimethoxysilane was added to the composition in an amount of 0.3-1.5% by weight. The presence of methoxy groups on the silicon atom enhances adhesion to the reinforcing filler or substrate surface, while the epoxy group allows it to integrate into the three-dimensional polymer network.

[0057]

[0058] Chemical formula of 3-glycidoxypropyltrimethoxysilane

[0059] A study of the microstructure of carbon fiber reinforced plastics showed that in a carbon fiber reinforced plastic sample manufactured without adding 3-glycidoxytrimethoxysilane to the epoxy binder, the microphase structure of the matrix is ​​two-phase, with weakly expressed separation of matrix particle aggregates, and the orientation of the matrix at the interface with the carbon fiber is practically absent (Fig. 1a).

[0060] On the other hand, in the carbon fiber composite sample produced with the addition of 3-glycidoxytrimethoxysilane epoxy binder, the matrix microphase structure is single-phase, indicating better compatibility of the polymer binder components. The microphase particles have a clear interface between them and a pronounced orientation at the boundary with the carbon fiber, indicating high adhesion of the polymer matrix to the carbon fiber (Fig. 1b).

[0061] An additional advantage of the proposed invention is the ability to manufacture large-sized products from PCM with stable strength characteristics using winding or injection molding technologies, compared to the costly and quality-unstable contact molding technology.

[0062] Another advantage is the increase in adhesion between the binder and the reinforcing filler, as well as the formation of a more tightly cross-linked microstructure due to the addition of dicyandiamide, which ensures the reaction proceeds through a polymerization mechanism, reduces the curing time by accelerating amine hardeners, and also initiates the cross-linking reaction between the epoxy oligomer and rubber.

[0063] Examples of implementation

[0064] Example 1-3

[0065] The binder was obtained by sequentially preparing component A (the resin part) and component B (the hardener). Chemical components requiring no additional purification were sequentially added to the reactor.

[0066] To prepare component A:

[0067] The epoxy resin, active diluent, adhesion additive, and dicyandiamide were loaded into the reactor. The mixture was then heated to 130°C and the rubber was added. After the components were fully combined, the reaction mixture was cooled to 50°C and drained.

[0068] To prepare component B:

[0069] Isophoronediamine and a mixture of polyhydroxyamines (Jeffamine D-230 and Jeffamine T-403) were loaded into the reactor at room temperature. After the components were completely combined, the reaction mixture was drained.

[0070] Example 4, 5

[0071] To prepare component A:

[0072] The epoxy resin, active diluent, adhesion additive, and dicyandiamide were loaded into the reactor. The mixture was then heated to 130°C and the rubber was added. After the components were fully combined, the reaction mixture was cooled to 50°C and drained.

[0073] To prepare component B:

[0074] Isophoronediamine, a mixture of polyhydroxyamines (Jeffamine D-230 and Jeffamine T-403), and dicyandiamide were loaded into the reactor at room temperature, after which the mixture was heated to 100°C. After the components were completely combined, the reaction mixture was cooled and drained.

[0075] The composition of the proposed binder and the binder taken as a prototype are given in Table 1.

[0076] Specimens for mechanical testing of the cured matrix were prepared by casting into a mold using two curing modes: 5 days at a temperature of 21±3°C and 6 hours at a curing temperature of 70°C. Samples of the uncured binder were pre-evacuated for 30 minutes.

[0077] Getting RMB

[0078] Carbon fiber reinforced plastic samples, as in the prototype, were manufactured on the basis of UMT49S-12K carbon fiber bundle by continuous winding with a binder content of 31.0-37.0 wt.% (Table 1) at curing temperatures of 5 days at a temperature of 21±3°C (mode 1) and 70°C for 6 hours (mode 2).

[0079] Characteristics of the binder samples and carbon fiber reinforced plastic based on it are given in Table 2.

[0080] Study of the effect of the adhesive additive on the strength and rheological characteristics of the binder showed that the introduction of 0.5 wt.% 3-glycidoxypropyltrimethoxysilane increases the strength of carbon fiber reinforced plastic from 4.5 MPa to 4.8 MPa (comparison of binder samples with the additive and a sample without the adhesive additive, Fig. 1).

[0081] As the obtained data showed, the declared epoxy binder and the PCM based on it demonstrate improved indicators of technological viability, strength and contribute to obtaining improved properties of the PCM based on it.

[0082]

[0083]

Claims

1. An epoxy binder for producing a polymer composite material, comprising an epoxy resin, a reactive diluent for epoxy resins and a curing system, characterized in that it contains, as the epoxy resin, a liquid epoxy resin based on Bisphenol A with an epoxy group content of 180 to 200 g / eq, and as the curing system - dicyandiamide, isophoronediamine and a mixture of polyoxypropylenediamines, in addition, the epoxy binder includes an elasticizing additive - low-molecular-weight butadiene-acrylonitrile rubber, an adhesive additive - 3-glycidoxytrimethoxysilane in the following quantities, mass %: Bisphenol A epoxy resin 55-63 active diluent for epoxy resins 15,5-19,3 dicyandiamide 0,06-0,4 isophoronediamine 5,5-8,0 mixture of polyoxypropylenediamines 15,0-19,0 3-glycidoxytrimethoxysilane 0,3-1,5 elasticizing additive rest 2. A polymer composite material intended for the manufacture of products by continuous winding, comprising an epoxy binder and a carbon fiber filler, characterized in that it contains a binder according to paragraph 1 as an epoxy binder and the ratio of the components is, in mass %: epoxy binder 31-37 carbon fiber filler 63-69

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