TWI610974B - Use of a mixture of difunctional epoxy with monofunctional primary amine compound and/or difunctional secondary amine curing agent; composites comprising the mixture and the manufacture method thereof - Google Patents

Abstract

The present invention provides a mixture of a difunctional epoxy resin and a monofunctional primary amine hardener and/or a difunctional secondary amine hardener as a prepreg for impregnating different materials to form a thermoplastic composite. And a thermoplastic composite and a method of preparation.

Description

Use of a mixture of a difunctional epoxy resin and a monofunctional primary amine hardener and/or a difunctional secondary amine hardener as a prepreg, a composite material containing the same, and a preparation method thereof

The invention relates to the use of a mixture, in particular to a use of a mixture of a difunctional epoxy resin and a monofunctional primary amine hardener and/or a bifunctional secondary amine hardener as a prepreg, a thermoplastic composite and A method of preparing the same.

Materials are the mother of industry, and composite materials (Composite Materials) is the mainstream of the modern materials industry. Composite materials have the characteristics of high strength, light weight, acid and alkali resistance, weather resistance, etc., and combine the advantages of various materials. They have gradually replaced traditional metal materials, ceramic materials, and even general polymer materials, and are widely used in various industries.

A composite material is a heterogeneous solid material composed of two or more substances having different physical and chemical properties. In the composite material, there is usually one continuous phase called a substrate; the other phase is a dispersed phase called Reinforcing material.

Composite materials can be divided into Polymer Matrix Composite according to their different substrates; Carbon/Carbon composites; Metal Matrix Composites (MMC); Ceramic matrix composites (Ceramic Matrix Composites, CMC), etc. The dispersed phase in the composite material can be divided into fibrous composite materials, granular composite materials, laminated composite materials, flaky composite materials or filled composite materials, etc. depending on the reinforcing materials.

Among them, high-strength and light-weight polymer resin fiber composite materials have attracted the most attention in recent years, and have begun to replace a large number of metal alloy products, and the output and application fields have also been expanded, and have been obtained in the automotive, electronics, electrical, building materials and other industries. A wide range of applications.

According to the polymer resin substrate, it can be divided into two systems of a thermosetting composite and a thermoplastic composite. Thermoplastic composites made of thermoplastic resin substrates combined with reinforcing materials have many advantages, such as high toughness, good impact resistance, stable prepreg, no storage time limitation, short manufacturing cycle, good chemical resistance, and moisture absorption. Low rate, repeatable processing, etc. In addition, it has two advantages, such as high-efficiency processing form and recyclable product in the process. Therefore, it is more favored by the processing method than the thermosetting composite material.

At present, the main method for manufacturing thermoplastic composites on the market is hot melt method (also known as melt impregnation method) or solvent method; the melt impregnation method heats and melts the resin, and then the reinforcing material is impregnated by molten resin; solvent method The solvent is used to completely dissolve the resin, and the thermoplastic resin is changed or lowered at a normal temperature (from solid to liquid) and viscosity, and the impregnated reinforcing material is impregnated, and the solvent is volatilized after the impregnation is completed.

Although it is known that related technologies can be used to prepare thermoplastic composites, the solvent method uses a large amount of organic solvents in the process, which discharges a large amount of organic volatiles and is liable to cause environmental pollution; the hot melt method is impregnated with reinforcing materials (or dispersed phases). Poor property, easy to cause defects in the finished layer of composite materials. In addition, the biggest problem facing thermoplastic composites today is the melting of thermoplastic resins. The temperature is high and the viscosity is also high, so it is quite difficult to prepare the prepreg.

In order to solve the above problems, the present invention utilizes the low viscosity property of the epoxy resin mixed with the amine hardener, so that the resin can be effectively impregnated with the reinforcing material without using the solvent, and then the impregnation is performed. In situ polymerization to form a thermoplastic composite.

The inventors have unexpectedly discovered that unlike conventional bifunctional epoxy resins which generally form thermosetting resins with polyfunctional amines, the inventors have employed monofunctional primary amine hardeners and/or difunctional secondary amine hardeners. The bifunctional epoxy resin is formed into a thermoplastic resin, and the thermoplastic composite material has a better process and efficacy, and the bifunctional epoxy resin used can be directly polymerized in a state of being impregnated with the dispersed phase. That is, the bifunctional epoxy resin can be first impregnated, and then polymerized in a state in which the dispersed phase has been impregnated, so that there is no problem that it is difficult to impregnate in the past.

Accordingly, it is a primary object of the present invention to provide a mixture of a difunctional epoxy resin and a monofunctional primary amine hardener and/or a difunctional secondary amine hardener as a prepreg for impregnating fibers. After in situ polymerization, a thermoplastic composite is formed.

In a preferred embodiment, the difunctional epoxy resin contains one or more 60 to 100% by weight epoxy resin mixtures and contains 0 to 25% by weight of a functional additive.

In another preferred embodiment, the difunctional epoxy resin is one having an epoxy equivalent weight (EEW) of from 50 to 650.

其中，X₁代表C₄~C₁₈烷基；n為0~20；X₂至X₂₁可為相同或不同，且代表H、P、烷基或鹵素；且Y代表S、O或C原子。 In another preferred embodiment, the difunctional epoxy resin comprises or blends the following formulas (I) to (IV):

Wherein X ₁ represents a C ₄ -C ₁₈ alkyl group; n is 0-20; X ₂ to X ₂₁ may be the same or different and represent H, P, alkyl or halogen; and Y represents an S, O or C atom. .

In another preferred embodiment, the monofunctional primary amine hardener and/or the difunctional secondary amine hardener comprises 80 to 100% by weight of one or more monofunctional primary amines and/or difunctional groups. A secondary amine mixture, 0 to 10% by weight of a functional additive.

In another preferred embodiment, the functional additive is selected from the group consisting of low shrinkage agents, flame retardants, UV lightfasting agents, abrasion resistant agents, and toughening agents.

其中，R_a為烷基、芳基或芳烷基；R_b為烷基或芳基；R_c為烷基。 In another preferred embodiment, the monofunctional primary amine hardener and/or the difunctional secondary amine hardener are either included or mixed with the following formulae (V) to (VII):

Wherein R _a is an alkyl group, an aryl group or an aralkyl group; R _b is an alkyl group or an aryl group; and R _c is an alkyl group.

Another object of the present invention is to provide a method for preparing a thermoplastic composite comprising: mixing a bifunctional epoxy resin with a monofunctional primary amine hardener and/or a difunctional secondary amine hardener to form a prepreg, and The mixture is impregnated with a dispersed phase and polymerized in situ.

In a preferred embodiment, the prepreg impregnated dispersed phase is formed by hand lay-up, brushing or vacuum infusion, and can also be applied by conventional Drum Winding and hot melt impregnation processes (Hot). -melt Impregnation) and other fiber-reinforced composite materials are impregnated and dispersed, and then heated for in-situ polymerization.

In a preferred embodiment, when the mixture is of low viscosity, the prepreg impregnated dispersed phase is passed through Drum Winding, Filament-Winding or Pultrusion. The mixture was heated in situ by heating.

In a preferred embodiment, when the mixture is of high viscosity, the prepreg impregnated dispersed phase is impregnated by a hot-melt impregnation process, and then heated for in-situ polymerization. Hehe.

Another object of the present invention is to provide a thermoplastic composite material which is obtained by the above method.

Use of a mixture of a difunctional epoxy resin and a monofunctional primary amine hardener and/or a difunctional secondary amine hardener according to the present invention, a method of preparing a thermoplastic composite, and the composite material, compared to the prior The advantages produced by the technology are as follows: the invention does not use volatile materials, so it is more environmentally friendly; it does not require pulverizing grinding or film production, and saves energy; the thermoplastic composite material can be impregnated at a low temperature of less than 60 degrees, so the process is relatively easy; The characteristics make the composite material interlayer bond better; the thermoplastic composite material has the characteristics of flame resistance, fatigue resistance, impact resistance and yellowing resistance, so it can be applied to various fields.

Figure 1 shows the longitudinal section of a thermoplastic carbon fiber prepreg with an optical microscope FS-105 (100x magnification), a) a longitudinal section of a carbon fiber impregnated with PKHH by hot melt (200 ° C), and the inside of the fiber is partially dry. ; b) in the longitudinal section of the carbon fiber impregnated in Example 1, the fiber is completely infiltrated; c) is the longitudinal section of the carbon fiber impregnated in Example 4, the fiber is completely infiltrated; d) the longitudinal section of the carbon fiber impregnated in Example 5 The fiber is completely infiltrated.

The term "a" or "an" as used in this document may be used in the scope of the patent application or in the specification, but may also mean one or more or at least one.

Use of a mixture of a difunctional epoxy resin of the invention and a monofunctional primary amine hardener and/or a difunctional secondary amine hardener

One of the main objects of the present invention is to provide a difunctional epoxy resin and A mixture of a monofunctional primary amine hardener and/or a difunctional secondary amine hardener as a prepreg for in situ polymerization after impregnation of a dispersed phase to form a thermoplastic composite.

The term "prepreg" as used herein refers to an uncured slag of a dispersed phase (eg, fiber, granule, laminate, sheet, or filler) used in an impregnated composite, which is a mixed bifunctional ring. A mixture of an oxyresin and a monofunctional primary amine hardener and/or a difunctional secondary amine hardener, but the difunctional epoxy is not yet cured.

The term "dispersed phase" as used herein refers to a material that is different in physical and chemical properties from the mixture of the difunctional epoxy resin of the present invention and the monofunctional primary amine hardener and/or the difunctional secondary amine hardener. It may also be referred to as "reinforcing material", and examples of the dispersed phase may be fibrous materials, particulate materials, laminated materials, sheet materials or filler materials, of which fiber materials are preferred.

In the use of the present invention, the difunctional epoxy resin contains one or more of 60 to 100% by weight of an epoxy resin mixture and contains 0 to 25% by weight of a functional additive.

In the use of the present invention, the difunctional epoxy resin preferably has an epoxy equivalent weight (EEW) of from 50 to 650, more preferably from 150 to 650.

其中，X₁代表C₄~C₁₈烷基；n為0~20；X₂至X₂₁可為相同或不同，且代表H、P、烷基或鹵素；且Y代表S、O或C原子。 In the use of the invention, wherein the difunctional epoxy resin comprises either or a combination of the following formulae (I) to (IV):

Wherein X ₁ represents a C ₄ -C ₁₈ alkyl group; n is 0-20; X ₂ to X ₂₁ may be the same or different and represent H, P, alkyl or halogen; and Y represents an S, O or C atom. .

The above bifunctional epoxy resin may be, but not limited to, bisphenol A epoxy resin (DGEBA), tetrabromobisphenol A epoxy resin (NPEB-340), bisphenol F epoxy resin (DGEBF). , resorcinol diglycidyl ether and the like.

In the use of the present invention, the monofunctional primary amine hardener and/or the difunctional secondary amine hardener comprises 80 to 100% by weight or more than one monofunctional primary amine and/or difunctional second Grade amine mixture, 0~10wt% functional additive.

In the use of the present invention, the viscosity of the mixture is preferably at 25 ° C, between 100 and 8000 cps, more preferably between 120 and 400 cps, and most preferably between 100 and 150 cps.

In the use of the present invention, the functional additive is selected from the group consisting of low shrinkage agents, flame retardants, UV auxiliaries, abrasion inhibitors, and toughening agents. The types of additives have been introduced in the prior art, but the actual selection and dosage must be available on the basis of the experiment.

In the use of the present invention, wherein the monofunctional primary amine hardener and/or the difunctional secondary amine hardener are included or mixed with the following formulae (V) to (VII):

Wherein R _a is an alkyl group, an aryl group or an aralkyl group; R _b is an alkyl group or an aryl group; and R _c is an alkyl group.

The above-mentioned one-stage amine and/or difunctional secondary amine hardener, such as an aliphatic amine or an aromatic amine, wherein preferably R _a to R _c represent a C ₁ to C ₁₀ short-chain alkyl group, a C ₆ to C ₈ aryl group. And a C ₇ to C ₁₉ aralkyl group, more preferably benzylamine, n-butylamine, diethylenediamine or the like.

Method for preparing thermoplastic fiber composite material of the present invention

Another object of the present invention is to provide a method for preparing a thermoplastic composite comprising: mixing a bifunctional epoxy resin with a monofunctional primary amine hardener and/or a difunctional secondary amine hardener to form a prepreg, and The mixture is impregnated with a dispersed phase and polymerized in situ.

The method of the present invention is to mix a uncured bifunctional epoxy resin mixed monofunctional primary amine hardener and/or a bifunctional secondary amine hardener to form a prepreg, which is mixed with a hardener by using a bifunctional epoxy resin. The viscosity is reduced so that it can be effectively impregnated with the dispersed phase, and then the in-situ polymerization polymerizes the resin of the mixture to form a thermoplastic composite.

As used herein, the term "effectively impregnated" means mixing a uncured bifunctional epoxy resin mixed monofunctional primary amine hardener and/or a difunctional secondary amine hardener to form a prepreg, followed by impregnation with the dispersed phase. After the curing, the bifunctional epoxy resin can be uniformly combined with the dispersion; visually, it can be seen that about 90% or more of the difunctional epoxy resin can be uniformly combined with the dispersion, preferably about 95% or more. The base epoxy resin can be uniformly combined with the dispersion, and more preferably 98% or more of the difunctional epoxy resin can be uniformly combined with the dispersion.

The in-situ polymerization in the present invention means that the uncured bifunctional epoxy resin is directly cured in a state where it is effectively impregnated with the dispersed phase; the requirement of the in-situ polymerization method is that the polymerization speed of the monomer is fast and the reaction is easy to control. . In the present invention, the in-situ polymerization system utilizes the characteristics of small initial molecular weight, low viscosity, and good fluidity of the monomer, so that the dispersed phase and the monomer are first impregnated therein, and then directly cured. The curing conditions (such as temperature, time, etc.) can be adjusted according to different resins and hardeners, but it is preferably a stepwise temperature curing, for example, about one hour at 30 to 60 ° C, and then about one at 80 to 100 ° C. Hours, finally curing at 110 to 140 ° C for about two hours, preferably at about 30 ° C for about one hour, then at 100 ° C for about one hour, and finally at 120 ° C for about two hours to cure; or, can be The curing is carried out at about 30 to 60 ° C for about half an hour, followed by about two hours at 140 to 180 ° C, preferably at about 50 ° C for about half an hour, followed by curing at about 160 ° C for about two hours.

The dispersed phase used in the method of the present invention is preferably a fibrous material, and the fibrous material is preferably a reinforcing fiber having an aspect ratio of 100 or more (more preferably 1,000 or more). In addition, A reinforced fiber woven fabric (reinforced fiber woven fabric, reinforced fiber woven fabric, reinforced fiber woven fabric, reinforced fiber nonwoven fabric, or the like) can also be used. By using a reinforced fiber or a woven fabric having an aspect ratio or more, it is possible to increase the reinforcing strength of the thermoplastic resin and to produce a fiber composite material having excellent mechanical properties.

As the reinforcing fiber, for example, an organic fiber such as carbon fiber or melamine fiber or an inorganic fiber such as glass fiber can be used, and carbon fiber is preferably used.

The diameter of the fiber filament used as the reinforced fiber may be about 3 to 23 μm, and as the type of the glass fiber, E glass or S glass which is particularly suitable for use as a reinforcing fiber, and C glass or A glass may be used. There are no special restrictions. The glass fiber filaments may be round or oval, and are not particularly limited.

As the form of the glass fiber, short fibers such as glass fiber nits, long fibers such as glass roving and glass fiber yarn, and the like can be used. Further, the glass fiber may be surface-treated with a surface treatment agent such as a decane coupling agent.

In the method of the present invention, the prepreg impregnated dispersed phase material is formed by hand lay-up, brush forming or vacuum infusion. Hand lay-up is carried out by hand work, that is, laying a reinforcing material or a dispersed phase (reinforcing material such as fiber material), hand-paste resin until the thickness of the desired plastic product, and then obtaining a thermoplastic composite by curing; Brush forming can be done manually or mechanically, after laying the reinforcing material or dispersed phase (reinforcing material such as fiber material), coating the resin until the thickness of the desired plastic product, and then obtaining the thermoplastic composite by curing; vacuum infusion For example, a single-sided mold can be used, and the surface of the mold is covered with glass fiber and a sealed vacuum bag or vacuum film, vacuum is taken from the closed space of the glass fiber in the mold, and then the resin is penetrated by the vacuum pressure to wet the fiber material, and then the resin and the resin are The fiber is formed after curing.

In addition, when the mixture is impregnated with a fibrous material, a prepreg formed by mixing a difunctional epoxy resin with a monofunctional primary amine hardener and/or a difunctional secondary amine hardener can be produced by a conventional method. Mixture with fibrous materials. When the reinforcing fiber to be used does not have a two-dimensional shape of a reinforced fiber woven fabric, the mixture is obtained by adding short fiber-like reinforcing fibers to an uncured resin, followed by stirring and mixing, and then curing in situ.

In a preferred embodiment, when the mixture is of low viscosity, the prepreg impregnated image is passed through Drum Winding, Filament-Winding or Pultrusion. Further, the in-situ polymerization is carried out by heating, wherein the term "low viscosity" means a preferred viscosity range of 50,000 cps or less, more preferably a viscosity value of 10,000 cps or less, and most preferably 500 cps or less.

In a preferred embodiment, when the mixture is of high viscosity, the prepreg impregnated image is impregnated by a hot-melt impregnation process and then heated for in-situ polymerization, wherein the term "high viscosity" refers to A preferred viscosity range is above 50,000 cps.

The mixture may contain an uncured resin and a reinforcing fiber as essential components, and may also be added as a low-shrinking agent, a flame-resistant agent, an ultraviolet-resistant auxiliary agent, a wear-resistant technique, a toughening agent, or the like as a functional additive.

Since the polymerization reaction occurs in the presence of the reinforcing fibers and any of the added components, the resulting fiber-reinforced thermoplastic plastic is a plastic in which a reinforcing fiber and any additional component are blended in a thermoplastic plastic. Further, since the resin before the high molecular weight is compared with the case of the reinforced fiber, the interface between the thermoplastic plastic and the reinforced fiber is excellent, and the mechanical properties (shear strength, impact strength, and the like) of the product are excellent.

The above manufacturing method of the present invention injects the mixture obtained in the mixing step In a mold having a desired shape, or by laminating a substance having a viscosity-adjusting property by hand lay-up (hand lay up), a thermoplastic fiber composite material can be formed by a polymerization reaction such as heating of the whole. A molded article of various shapes can be easily and without defects, as represented by a large molded product or a molded product having a complicated shape. Further, since the reinforcing fibers are added before the uncured resin is polymerized, the reinforcing fibers can be polymerized in a state of being sufficiently wetted in the uncured resin. Therefore, the obtained fiber-reinforced thermoplastic does not damage the reinforcing fibers, and the generation of voids in the interface between the thermoplastic and the reinforcing fibers can be sufficiently suppressed.

The thermoplastic fiber composite material prepared by the above method can exhibit the same mechanical properties as a composite material using a resin as a base resin in the vicinity of normal temperature (for example, 20 to 90 ° C), and at a high temperature (for example, at 100 ° C or higher) It is easy to liquefy, and a thermoplastic fiber composite material which can be processed twice or reused and recycled can be obtained.

Thermoplastic fiber composite material of the invention

Another object of the present invention is to provide a thermoplastic fiber composite material which is obtained by the above method.

Hereinafter, preferred embodiments of the present invention will be described in more detail, but the present invention is not limited to the embodiments.

Example 1

95.0 g of bisphenol A type epoxy resin (DGEBA, EEW=176~184) and 27.1 g of benzylamine were mixed and stirred uniformly. The resin composition was uniformly applied to a 3K carbon fiber cloth by hand lamination within 2 hours, and then pressure-rolled at 50 ° C. Curing was carried out at 50 ° C (1 hour), followed by 100 ° C (1 hour), and finally 150 ° C (2 hours) to obtain a thermoplastic composite.

Example 2

21.0 g of bisphenol A type epoxy resin (DGEBA, EEW=176~184), 4.1 g of n-butylamine and 1.5 g of triethyl phosphate were mixed and stirred uniformly. The resin composition was uniformly applied to a 3K carbon fiber cloth by hand lamination within 2 hours, and then pressure-rolled at 50 ° C. Curing was carried out at 50 ° C (1 hour), followed by 100 ° C (1 hour), and finally 150 ° C (2 hours) to obtain a thermoplastic composite.

Example 3

50.0 g of bisphenol A type epoxy resin (DGEBA, EEW=176~184), 11.46 g of diethylenediamine (dissolved in 2 g of methanol) and 0.6 g of maleic acid were mixed and stirred uniformly. The resin composition was uniformly applied to a 3K carbon fiber cloth by hand lamination within 2 hours, and then pressure-rolled at 50 ° C. Curing was carried out at 50 ° C (1 hour), followed by 100 ° C (1 hour), and finally at 120 ° C (2 hours) to obtain a thermoplastic composite.

Example 4

50.0 g of tetrabromobisphenol A type epoxy resin (NPEB-340, EEW=340-360), heated to 120 ° C, mixed with 8.12 g of benzylamine and stirred uniformly (mixed at 25 ° C, viscosity is 4000-8000cps). Then, evenly spread the hand layer on the 3K carbon fiber cloth in half an hour, and then pressurize the roller at 100 °C. The post-curing was carried out at 80 ° C (half hour) followed by 160 ° C (2 hours) to obtain a thermoplastic carbon fiber composite.

Example 5

50.0 g of bisphenol F type epoxy resin (DGEBF, EEW=170-174) was mixed with 15.75 g of benzylamine and stirred uniformly (mixing viscosity was 120-300 cps at 25 ° C). Then, evenly spread the hand layer on the 3K carbon fiber cloth in half an hour, and then pressurize the roller at 50 °C. The post-curing was carried out at 50 ° C (half hour) followed by 160 ° C (2 hours) to obtain a thermoplastic carbon fiber composite.

Example 6

50.0 g of resorcinol diglycidyl ether (EEW=111.12) was mixed with 24.11 g of benzylamine and stirred uniformly (mixing viscosity was 120-300 cps at 25 ° C). Then, it was evenly spread on a 3K carbon fiber cloth with a hand layer within half an hour and then pressure-rolled at 50 ° C. The post-curing was carried out at 50 ° C (half hour) followed by 160 ° C (2 hours) to obtain a thermoplastic carbon fiber composite.

Comparative example

The description will be made with reference to FIG.

Comparative thermoplastic resin PKHH (InChem Co.) and the present invention (Examples 1, 4, 5) were hot-melted by impregnation to produce a thermoplastic carbon fiber prepreg, and a thermoplastic carbon fiber prepreg (3K, FAW = 200) longitudinal section was as As shown in Fig. 1, the longitudinal section of the thermoplastic carbon fiber prepreg is observed by an optical microscope FS-105 (100x magnification), and Fig. 1a) is a longitudinal section of the PKHH impregnated with carbon fiber by a hot melt method (200 ° C), in detail, The film-like PKHH plastic is attached to a 3K carbon fiber cloth and coated with release paper. After preheating at 200 ° C for 30 minutes, it was subjected to hot roller pressure, and after cooling, PKHH thermoplastic prepreg was obtained. As a result, it was found that the inside of the fiber partially showed a dry yarn state, and only about 50% infiltration was visually observed. 1b), c), and d) are longitudinal sections of carbon fibers impregnated in Examples 1, 4, and 5, respectively, and the fibers are completely (100%) infiltrated visually.

A comparison of the above examples and comparative examples reveals a mixture of a difunctional epoxy resin and a monofunctional primary amine hardener and/or a difunctional secondary amine hardener according to the present invention; since the mixture has a low temperature of less than 60 degrees It can be impregnated, so the process is easier; and due to the characteristics of the mixture, the composite layer formed by the fiber and the fiber is better; therefore, the obtained thermoplastic fiber composite material can be added with different functional additives. It is resistant to fire, fatigue, impact, and yellowing, so it can be used in many fields.

Claims (11)

A mixture of a difunctional epoxy resin and a monofunctional primary amine hardener and/or a difunctional secondary amine hardener as a prepreg for in-situ polymerization after impregnation of a dispersed phase a thermoplastic composite material, wherein the monofunctional primary amine hardener and/or the difunctional secondary amine hardener is included or mixed with the following formulae (V) to (VII): Wherein R _a , R _b , R _c are a C ₁ to C ₁₀ short-chain alkyl group, a C ₆ to C ₈ aryl group or a C ₇ to C ₁₉ aralkyl group. The use of claim 1, wherein the difunctional epoxy resin contains one or more 60 to 100% by weight epoxy resin mixtures and contains 0 to 25% by weight of a functional additive. The use of claim 1, wherein the difunctional epoxy resin is an epoxy equivalent (EEW) of from 50 to 650. The use of claim 1, wherein the difunctional epoxy resin comprises or blends the following formulas (I) to (IV): Wherein X ₁ represents a C ₄ -C ₁₈ alkyl group; n is 0-20; X ₂ to X ₂₁ may be the same or different and represent H, P, alkyl or halogen; and Y represents an S, O or C atom. . The use of claim 1, wherein the monofunctional primary amine hardener and/or the difunctional secondary amine hardener comprises 80 to 100% by weight of one or more monofunctional primary amines and/or difunctional groups A secondary amine mixture, 0 to 10% by weight of a functional additive. The use of claim 2 or 5, wherein the functional additive is selected from the group consisting of a low shrinkage agent, a flame retardant, an ultraviolet light resistant additive, an antiwear agent, and a toughening agent. A method of preparing a thermoplastic composite comprising: forming a prepreg by mixing a bifunctional epoxy resin with a monofunctional primary amine hardener and/or a difunctional secondary amine hardener, and impregnating the mixture with a dispersed phase In-situ polymerization wherein the monofunctional primary amine hardener and/or the difunctional secondary amine hardener are included or mixed with the following formulae (V) to (VII): Wherein R _a , R _b , R _c are a C ₁ to C ₁₀ short-chain alkyl group, a C ₆ to C ₈ aryl group or a C ₇ to C ₁₉ aralkyl group. The method of claim 7, wherein the prepreg impregnated dispersed phase is formed by hand lay-up, brush forming or vacuum infusion. The method of claim 7, wherein the prepreg impregnated dispersed phase is passed through a Drum Winding, a Filament-Winding or a Pultrusion, wherein the mixture is of low viscosity. The mixture was heated in situ by heating. In the method of claim 7, wherein the mixture is of high viscosity, the prepreg impregnated dispersed phase is impregnated by a hot-melt impregnation process and heated for in-situ polymerization. A thermoplastic composite produced by the method of claim 7 or 8 or 9 or 10.