RU2762559C1 - Heat-resistant low-viscosity binder for the manufacture of products by methods of vacuum infusion and impregnation under pressure and a method for its production - Google Patents

Abstract

FIELD: heat-resistant low-viscosity binder production.

SUBSTANCE: invention relates to a composition and a method for producing a heat-resistant low-viscosity binder and is intended for the manufacture of a polymer composite material by vacuum infusion or injection molding and can be used in aerospace, automotive, shipbuilding and other industries. A heat-resistant low-viscosity binder for the manufacture of articles by vacuum infusion and pressure impregnation includes epoxy resin, triglycidyl phosphate, an aromatic amine hardener, epoxy novolac resin was selected as an epoxy resin, diethyltoluene diamine was selected as an aromatic amine hardener, and the binder additionally contains monomerthalonitrile. The invention also relates to a method for producing the specified heat-resistant low-viscosity binder, which consists in the fact that first a first mixture is prepared, for which to 100 wt.h. triglycidyl phosphate add 10-90 wt.h. phthalonitrile monomer, the resulting mixture is heated to a temperature of 80°C with thorough stirring; then prepare the second mixture, for which to 20-60 wt.h. epoxy novolac resin add a stoichiometric amount of the hardener diethyltoluene diamine, the resulting mixture is thoroughly mixed; the resulting mixtures are combined, thoroughly mixed and cured according to the following regime: 2 hours at 100°С, 2 hours at 150°С, 2 hours at 250°С.

EFFECT: invention makes it possible to obtain a heat-resistant low-viscosity binder with high heat resistance and low-viscosity.

2 cl, 2 dwg

Description

The invention relates to a composition and a method for producing a binder and is intended for the manufacture of a polymer composite material (PCM) by vacuum infusion or pressure impregnation. It can be used in aerospace, automotive, shipbuilding and other industries.

A known method of producing carbon plastics based on a heat-resistant binder [US Pat. RU 2572139]. The essence is a method for producing carbon fiber-reinforced plastic based on a heat-resistant binder, in which a binder in the form of a powder is placed on the surface of a fibrous carbon filler, the binder is melted, the filler is impregnated with it, and a carbon fiber-reinforced plastic is formed from the filler impregnated with the binder in a mold, characterized in that phthalonitrile binder is used as a binder, and as a filler - a carbon equal-strength or unidirectional fabric, a preform is formed (a preform is a workpiece made of dry reinforcing material (carbon, glass, organo-fiber or fabric) or by vacuum infusion. by their mutual fixation using a solution of cyan ether in acetone in the amount of 3-10 wt.% of cyan ether to the mass of the specified filler, the preform is placed in the mold, the binder is placed in the form of a powder on the surface of the preform or between the layers of the filler, and a vacuum is applied. wetting the preform with a molten binder at a binder temperature of 185-205 ° C for 30-60 minutes, then carbon fiber is molded from the preform in a mold in a stepwise heating mode, followed by heat treatment of the carbon fiber in an inert atmosphere. A method of producing carbon fiber reinforced plastic, characterized in that a binder is placed in the form of a powder on the surface of the preform or between its layers in a ratio of 1.0-1.3 to the weight of the filler. A method for producing CFRP, characterized in that a phthalonitrile binder is used as a binder, and CFRP is molded in a mold in a stepwise heating mode up to a temperature of 300 ° C, followed by heat treatment in an inert atmosphere at a temperature of 350-400 ° C.

The disadvantage of the known invention is the impossibility of using this phthalonitrile binder to obtain a composite material by infusion and impregnation under pressure due to the fact that the binder is in a powdery state.

From the investigated prior art, the applicant identified an invention under the patent RU 2638307 "Modified with organophosphate fragments of phthalonitrile monomer, a method for its production, a binder based on it and prepreg". The essence is a phthalonitrile monomer modified with organophosphate fragments, characterized by the general formula

where R is a radical selected from the group consisting of aryl, alkyl, aryloxy or alkyloxy substituents;

X is a divalent aryl substituent selected from the group consisting of phenylenes and naphthylenes.

Phthalonitrile monomer characterized in that R contains a radical selected from the group consisting of OCH ₃ , OC ₆ H ₅ , OC ₁₀ H ₇ , C ₆ H ₅ . A method of obtaining a phthalonitrile monomer modified with organophosphorus fragments in accordance with claim 1 of the formula, characterized in that a reaction reaction is carried out of at least one hydroxyl-containing phthalonitrile and a phosphorus-containing substance selected from the group consisting of alkyl- or aryl-phosphoric acid, alkyl- or aryl-phosphorous acid , dichloroanhydride of alkyl- or arylphosphoric acid and dichloroanhydride of alkyl- or arylphosphorous acid, followed by extraction of the target product from the reaction products in the form of phthalonitrile monomer modified with organophosphorus fragments. The method according to claim 3, characterized in that phthalonitrile selected from the group consisting of (4- (2-hydroxyphenoxy) phthalonitrile, 4- (3-hydroxyphenoxy) phthalonitrile and 4- (4-hydroxyphenoxy) phthalonitrile) is used as the hydroxyl-containing phthalonitrile ... The method according to claim 3, characterized in that before the reaction reaction said hydroxyl-containing phthalonitrile is mixed with a suitable solvent. The method according to claim 3, characterized in that the reaction is carried out in the presence of a base. The method according to claim 3, characterized in that the extraction of the target product is carried out by successive filtration of the reaction products to obtain the filtrate, subsequent evaporation of the filtrate, dissolving the evaporation product, washing the solution with water and isolating the target product from it. A binder, characterized in that it includes a phthalonitrile monomer modified with organophosphorus fragments in accordance with paragraphs. 1 and 2 of the formula and an aromatic diamine as a polymerization initiator. A binder according to claim 8, characterized in that it contains an aromatic diamine in an amount of up to 20 wt%. The binder according to claim 8, characterized in that it is used as a binder for the production of polymer composite materials by infusion technologies. A prepreg, characterized in that it is made of a binder in accordance with any of paragraphs. 8-10 formulas and reinforcing element. The prepreg according to claim 11, characterized in that, as a reinforcing element, it contains an element selected from the group including carbon directional ribbons, carbon fabrics, glass fabrics, glass unidirectional ribbons, carbon chopped fibers, glass chopped fibers.

Thus, the known technical solution describes a phthalonitrile monomer modified with organophosphorus fragments, a method for its production, a binder based on it, and prepreg. The binder is characterized in that it includes phthalonitrile monomer and an aromatic diamine as a polymerization initiator.

The disadvantage of the known technical solution in relation to the composition is the high viscosity (according to our own data) and high curing temperatures (200-375 ° C), as a result of which the known technical solution has lower consumer properties, since this binder does not allow high-quality and fast impregnation of the reinforcing filler by methods vacuum infusion and pressure impregnation. High curing temperatures of this binder can lead to high thermal stresses in the composite, which degrades the strength characteristics of the product.

Known invention under the patent RU 2606443 "Epoxy composition for the manufacture of products from polymer composite materials by vacuum infusion", the essence is an epoxy composition for polymer composite materials, containing an epoxy base, including epoxy resin and an active diluent - aliphatic diglycidyl ether, and a curing system based on a mixture of amine hardeners - polyether amine and isophorone diamine, characterized in that the epoxy base as an epoxy resin contains one or a mixture of bisphenol A resins with a molecular weight of 340 to 430, and as an active diluent it additionally contains an aromatic glycidyl ether, the ratio of polyether amine and isophorone diamine in hardening system is, masses. %: isophorone diamine - 60.0-90.0; polyetheramine -10.0-40.0. The epoxy composition according to claim 1, characterized in that the content in the epoxy base of epoxy resin or a mixture of resins based on bisphenol A, in mass. % is: 50.0-90.0. The epoxy composition according to claim 1, characterized in that the content in the epoxy base of aliphatic glycidyl ether, in mass. % is: 3.0-7.0. The epoxy composition according to claim 1, characterized in that the content of the aromatic glycidyl ether in the epoxy base, in mass. % is: 3.0-47.0. The epoxy composition according to claim 1, characterized in that the ratio of the epoxy base and the curing system in the final composition is, mass. h - 100: (22-33). The epoxy composition according to claim 1, characterized in that it additionally contains a colorant in the curing system in an amount of 0.0001-0.0010 mass. %. The epoxy composition of claim 6, wherein one of the following dyes is used: Methyl red, Brilliant green, or Bromothymol blue.

The disadvantage of the known technical solution is its low heat resistance (Tg = 101-110 ° C), which significantly reduces the upper limit of operation of composite materials based on it.

Known invention under the patent RU 2688539 "Epoxy binder for the manufacture of large-sized composite products, including equipment, and a method for manufacturing large-sized composite equipment", the essence is an epoxy binder for the manufacture of large-sized composite products, including equipment, from polymer composite materials by vacuum infusion epoxy resins and a cycloaliphatic hardener, where the first resin in the mixture is an epoxyaniline resin, the second resin is a resin selected from the group consisting of epoxyparaaminophenol and epoxymethaminophenol resins, and the cycloaliphatic hardener is a hardener selected from the group consisting of 3 , 5-trimethylcyclohexylamine, 1,2-diaminocyclohexane, 4,4'-diaminodicyclohexyl methane, 2,2'-dimethyl-4,4'-methylenebis (cyclohexylamine) in the following ratio, parts by weight:

A mixture of two epoxy resins one hundred Cycloaliphatic Hardener 57-63

where the content of the first resin in said mixture of two epoxy resins is 5-25 parts by weight, and the content of the second resin is 75-95 parts by weight. A binder according to claim 1, which further comprises an active diluent. The binder according to claim 2, which contains as an active diluent diglycidyl ether of butanediol-1,4 in an amount of up to 5 parts by weight. The binder according to claim 1, which further comprises a coloring agent. The binder according to claim 4, which contains dibutylamine-9,10-anthracenedione in an amount of up to 0.5 parts by weight as a coloring agent. A method of manufacturing large-sized tooling from a polymer composite material, including assembling a preform from a reinforcing fibrous filler, auxiliary materials and means on the surface of the master model, providing the subsequent impregnation of the said filler with a binder by the method of vacuum infusion; making a binder in accordance with any of the preceding claims; sealing the preform from step (a) with subsequent impregnation of the reinforcing fiber filler with a binder from step (b) by vacuum infusion; preliminary curing of the binder on a master model in the temperature range from room temperature to 30 ° C to obtain a semi-finished tooling; removal of semi-finished tooling from the master model; post-curing of a semi-finished tooling at a temperature not exceeding 200 ° С to obtain a tooling. The method according to claim 6, in which the binder in step (b) is made by mixing the components at a pressure not exceeding 10 mm Hg. The method according to claim 6, wherein the binder is made just before impregnating the preform in step (c). The method according to claim 6, in which the pre-curing in step (d) is carried out for 12-48 hours. The method according to claim 6, in which the post-curing in step (e) is carried out at a temperature of 160-200 ° C. The method according to claim 6. 6, in which the heating for post-curing is carried out stepwise in 7-9 steps with a heating rate not exceeding 1 ° C / min, and holding at each step for 2-6 hours. The method according to claim 6, in which cooling at the stage ( f) carried out at a rate not exceeding 5 ° C / min.

Briefly, the first resin in the mixture is an epoxyaniline resin, the second resin is a resin selected from the group consisting of epoxy paraaminophenol and epoxymetaminophenol resins. The cycloaliphatic hardener is a hardener selected from the group consisting of 3-aminomethyl-3,5,5-trimethylcyclohexylamine, 1,2-diaminocyclohexane, 4,4'-diaminodicyclohexylmethane, 2,2'-dimethyl-4,4'-methylenebis ( cyclohexylamine).

The disadvantage of the known technical solution is the high activity of the binder at room temperature, which greatly complicates its use for the manufacture of products by vacuum infusion and pressure impregnation methods, because in the manufacture of articles, difficulties arise in the molding process due to the rapid curing of the composition.

Known invention under the patent RU 2590563 "Heat-resistant epoxy binder for the manufacture of articles by impregnation under pressure", the essence is a heat-resistant epoxy binder for the manufacture of articles by impregnation under pressure, containing epoxy polyfunctional resin N, N, N ′, N′-tetraglycidyl-4, 4'-diamino-3,3'-dichlorodiphenylenemethane with dynamic viscosity at 50 ° C not more than 10.0 Pa · s, epoxy-bismaleimide resin containing 25 wt. parts 44 'of bismaleimidediphenylmethane and a hardener - 4,4'-diaminodiphenylsulfone, characterized in that the binder additionally contains one of the following active diluents:

- 3-glycidyloxypropyltrimethoxysilane;

- a mixture of 3-glycidyloxypropyltrimethoxysilane with the epichlorohydrin polymerization product in a 1: 1 ratio;

- a mixture of 3-glycidyloxypropyltrimethoxysilane with allylglycidyl ether in a ratio of 2: 3,

with the following ratio of components, wt%:

epoxy polyfunctional resin 35.2-36.6 epoxy bismaleimide resin 35.2-36.6 4,4'-diaminodiphenylsulfone 22.0-22.9 active diluent: 3-glycidyloxypropyltrimethoxysilane 3.9-5.4 a mixture of 3-glycidyloxypropyltrimethoxysilane with the polymerization product of epichlorohydrin in a 1: 1 ratio 5.4-6.9 a mixture of 3-glycidyloxypropyltrimethoxysilane with allylglycidyl ether in a ratio of 2: 3 6.9-7.6

The disadvantage of the known technical solution is the complex composition of the binder, which complicates and increases the duration and complexity of its preparation (dosing, mixing).

The closest in technical essence and the achieved technical result, selected by the applicant as a prototype, is the invention according to patent RU 2141493 "Binder for reinforced plastics" that as an active diluent it contains glycidyl esters of phosphorus acids of the general formula

with the following ratio of components, parts by weight:

Epoxy resin one hundred Phosphorus acid glycidyl esters 10 - 25

Aromatic Amine Hardener - Stoichiometric Amount.

Briefly, the binder includes an epoxy resin, an aromatic amine hardener, and an active diluent. As epoxy resins, resins of the ED-24, ED-22, ED-20, ED-18 grades [GOST 10587-84] and other oligomers of this series were used. The amine hardeners used were 4,4'-diaminodiphenylmethane (DADPM), 3,3'-dichloro, 4,4'-diaminodiphenylmethane (“diamex”), m-phenylenediamine (MPDA). The binder contains glycidyl esters of phosphorus acids as an active diluent.

The disadvantages of the prototype in relation to the composition are:

- insufficiently high heat resistance of the binder (200 ° C);

- insufficiently low viscosity of the binder (1500-10000 cP), which makes it difficult to use it for infusion processes and impregnation under pressure.

The task and the technical result of the claimed technical solution is the development of a composition of a heat-resistant low-viscosity binder for the manufacture of products by methods of vacuum infusion and impregnation under pressure and a method for its production, eliminating the disadvantages of the prototype, namely:

- increasing the heat resistance of the binder;

- reducing the viscosity of the binder for infusion processes and impregnation under pressure.

The essence of the claimed technical solution is a heat-resistant low-viscosity binder for the manufacture of articles by vacuum infusion and pressure impregnation, including an epoxy resin, triglycidyl phosphate, an aromatic amine hardener, characterized in that epoxy novolac resin is selected as an epoxy resin, diethyltol is selected as an aromatic amine hardener; the binder additionally contains phthalonitrile monomer, with the following ratio of components, parts by weight:

epoxy novolac resin 20-60 triglycidyl phosphate one hundred phthalonitrile monomer 10-90 diethyltoluene diamine stoichiometric amount

The method of obtaining a heat-resistant low-viscosity binder according to claim 1, which consists in the fact that first prepare the first mixture, for which to 100 wt. parts of triglycidyl phosphate add 10–90 wt. parts of phthalonitrile monomer, the resulting mixture is heated to a temperature of 80 ° C with thorough stirring; then prepare a second mixture, for which to 20-60 wt. a stoichiometric amount of diethyltoluene diamine hardener is added to parts of the epoxy novolac resin, the resulting mixture is thoroughly mixed; the resulting mixtures are combined, thoroughly mixed and cured according to the following regime: 2 hours at 100 ° C, 2 hours at 150 ° C, 2 hours at 250 ° C.

Get the declared binder.

The claimed sequence of actions has not been identified from the prior art.

The claimed technical solution is illustrated in Fig. 1 - Fig. 2.

Figure 1 presents Table 1, which shows the compositions of the claimed heat-resistant low-viscosity binder and binder according to the prototype.

Figure 2 presents Table 2, which shows the properties of the claimed heat-resistant low-viscosity binder and binder according to the prototype.

Next, the applicant provides a description of the claimed technical solution.

To achieve the set technical result, a heat-resistant low-viscosity binder was developed containing epoxy resin, triglycidyl phosphate, an aromatic hardener and phthalonitrile monomer as a modifier with the following ratio of components, parts by weight:

epoxy novolac resin - 20-60 triglycidyl phosphate - one hundred phthalonitrile monomer - 10-90 diethyltoluene diamine - stoichiometric amount.

Next, the applicant gives a description of the individual components of the claimed heat-resistant low-viscosity binder.

It is known that the use of epoxy novolac resins contributes to the production of polymers with high heat resistance. Epoxy novolac resins DER-354, DEN 425, DEN 431 (Olin) were used as epoxy resin.

For materials processed by vacuum infusion or pressure impregnation, the rheological characteristics of the binders are of particular importance. To reduce the viscosity and reduce the flammability of epoxy compositions, a phosphorus-containing epoxy oligomer, triglycidyl phosphate, was introduced, which is a low-viscosity transparent liquid.

The aromatic amine curing agent was DEH-650 grade diethyltoluene diamine (Dow Chemical Company).

It is known that polymers based on phthalonitriles are characterized by high values of heat resistance. Phthalonitrile monomers PN-3M (ITEKMA, Moscow) and VSN-31 (FGUP VIAM, Moscow) were used as a modifier.

The amount of the hardener was calculated based on the epoxy number of the resin and the stoichiometric coefficient of the hardener.

Next, the applicant gives a description of the claimed method for producing a heat-resistant low-viscosity binder.

Phthalonitrile monomer is a very highly viscous substance. Therefore, to optimize the mixing process of the components and achieve a higher homogeneity of the mixture, it is advisable to mix the components as follows.

First, a first mixture is prepared, for which 10-90 parts by weight of phthalonitrile monomer are added to 100 parts by weight of triglycidyl phosphate, the mixture is stirred using a laboratory mixer, heating in a water bath at a temperature of 80 ° C.

Then a second mixture is prepared, for which a stoichiometric amount of diethyltoluene diamine hardener is added to 20-60 mass parts of epoxy novolac resin, the resulting mixture is thoroughly mixed.

Then the resulting mixtures are combined, thoroughly mixed and cured according to the following regime: 100 ° C - 2 hours, 150 ° C - 2 hours, 250 ° C - 2 hours.

Get the declared binder.

The mode of obtaining a heat-resistant low-viscosity binder and the mode of its curing are selected by the applicant empirically.

The viscosity of the formulations was determined on a rotary dynamic rheometer DHR-2 (TA Instruments). The glass transition temperature and elastic modulus of the cured samples were determined by dynamic mechanical analysis on a DMA 242 E instrument (NETZSCH) at a heating rate of 5 K / min.

The compressive strength of the cured samples was determined according to GOST 4651-2014 “Plastics. Compression test method ".

Tensile strength was determined according to GOST 11262-2017 "Plastics. Tensile test method ". Flexural strength was determined according to GOST 4648-2014 "Plastics. Static bending test method ".

Further, the applicant provides examples of the implementation of the claimed technical solution.

Example 1. Obtaining a heat-resistant low-viscosity binder containing epoxy novolac resin 20 parts by weight, phthalonitrile monomer 10 parts by weight.

First, prepare the first mixture, for which 100 wt. parts of triglycidyl phosphate add 10-90 parts by weight of phthalonitrile monomer. The resulting mixture is stirred using a laboratory mixer, heating in a water bath at a temperature of 80 ° C.

Then a second mixture is prepared, for which 20 wt. a stoichiometric amount of diethyltoluene diamine hardener is added to parts of the epoxy novolac resin, the resulting mixture is thoroughly mixed.

The resulting mixtures are combined, mixed thoroughly, mixed and cured according to the following regime: 2 hours at 100 ° C, 2 hours at 150 ° C, 2 hours at 250 ° C.

Receive the declared heat-resistant low-viscosity binder.

Examples 2 - 10. Obtaining a heat-resistant low-viscosity binder containing epoxy novolac resin 20-60 wt.h., phthalonitrile monomer 10-90 wt.h.

A sequence of actions is carried out according to Example 1, characterized in that the amount of epoxy novolac resin and phthalonitrile monomer is changed in the range of the stated values.

The results are shown in Table 1 in Fig. 1. Table 1 also shows prototype data for comparison.

From the data given in Table 1, it can be seen that the compositions of the claimed heat-resistant low-viscosity binder were obtained in the entire range of the declared values of the content of the components.

In Table 2 of FIG. 2 shows the properties of the obtained according to Examples 1 to 10 heat-resistant low-viscosity binder and binder according to the prototype for comparison.

As can be seen from Table 2, the claimed heat-resistant low-viscosity binder (Examples 1-10) has:

- higher heat resistance compared to the prototype - increased from 155-200 ° C to 200-235 ° C, that is, the increase is on average 40 ° C,

- obtained sufficiently high physical and mechanical properties (compressive, tensile and bending strength) comparable to those of the prototype;

- the upper and lower ranges of viscosity are shifted to the region of lower values in comparison with those of the prototype.

Thus, from the above, we can conclude that the applicant has achieved the assigned tasks and the claimed technical result , exceeding the technical result of the prototype, namely:

- a composition of a heat-resistant low-viscosity binder has been developed, including an epoxy resin, triglycidyl phosphate, an aromatic amine hardener,

- a method for producing a binder has been developed, including mixing components, which include epoxy resin, triglycidyl phosphate, aromatic amine hardener and modifier;

- it is shown that the claimed binder has a higher heat resistance compared to the prototype, lower viscosity and comparable physical and mechanical properties to the prototype.

The claimed technical result was achieved by the fact that such an optimal composition of components and a method of mixing them were selected, which made it possible to obtain a binder with low viscosity, high heat resistance.

The claimed technical solution meets the "novelty" requirement of patentability for inventions, since at the date of the applicant's submission of the application materials from the studied prior art, no sources have been identified that have a set of features identical to the set of features of the claimed technical solution.

The claimed technical solution complies with the "inventive step" patentability requirement for inventions, since the combination of the claimed features provides for obtaining technical results that are not obvious to a specialist, exceeding the technical result of the prototype. The applicant from the investigated prior art has not identified compositions in which the claimed components would be used simultaneously in the claimed ratio and in the declared purpose, namely, in the composition of a heat-resistant low-viscosity binder. In this case, the ratio of the components was selected by the applicant empirically. The identified sources also lack the sequence of actions of the claimed method, therefore, the claimed method is not obvious to a specialist in the analyzed field of technology.

The claimed technical solution meets the condition of patentability "industrial applicability" for inventions, since the claimed composition can be obtained by using known components using standard equipment and known techniques.

Claims (3)

1. Heat-resistant low-viscosity binder for the manufacture of articles by vacuum infusion and pressure impregnation, including epoxy resin, triglycidyl phosphate, aromatic amine hardener, characterized in that epoxy novolac resin is selected as epoxy resin, diethyl toluene diamine is selected as an aromatic amine hardener, and phthalonitrile monomer, with the following ratio of components, parts by weight: epoxy novolac resin 20-60 triglycidyl phosphate one hundred phthalonitrile monomer 10-90 diethyltoluene diamine stoichiometric amount 2. The method of obtaining a heat-resistant low-viscosity binder according to claim 1, which consists in the fact that first prepare the first mixture, for which to 100 wt.h. triglycidyl phosphate add 10-90 wt.h. phthalonitrile monomer, the resulting mixture is heated to a temperature of 80 ° C with thorough stirring; then prepare the second mixture, for which to 20-60 wt.h. epoxy novolac resin add a stoichiometric amount of the hardener diethyltoluene diamine, the resulting mixture is thoroughly mixed; the resulting mixtures are combined, thoroughly mixed and cured according to the following regime: 2 hours at 100 ° C, 2 hours at 150 ° C, 2 hours at 250 ° C.

Images