TW202214738A - Precursor mixture of in situ polymerization type thermoplastic epoxy resin, epoxy resin composition, epoxy resin composition sheet, prepreg, and in situ polymerization type thermoplastic fiber-reinforced plastic using same - Google Patents

Abstract

The present invention provides: an epoxy resin composition which has excellent heat resistance and enables the achievement of an in situ polymerization type thermoplastic fiber-reinforced plastic that is able to be produced by a hot melt process; and a precursor mixture of this epoxy resin composition. A precursor mixture which is obtained by addition polymerization of a bifunctional epoxy resin and a bifunctional phenolic compound, and which is used for an in situ polymerization type thermoplastic epoxy resin. This precursor mixture is characterized in that: two or more kinds of bifunctional phenolic compounds are contained as essential components; the total of the bifunctional phenolic compounds relative to 1 mole of the bifunctional epoxy resin is from 0.9 to 1.1 moles; and the viscosity at 60 DEG C is from 1 Pa·s to 50 Pa·s.

Description

Precursor mixture for in-situ polymerization thermoplastic epoxy resin, epoxy resin composition, epoxy resin composition sheet, prepreg, and in-situ polymerization thermoplastic fiber reinforced plastic using the same

The present invention relates to an in-situ polymerized thermoplastic epoxy resin and thermoplastic fiber reinforced plastic. Here, the so-called in-situ polymerized thermoplastic resin refers to a low molecular weight at the time of shipment from the factory, and on the other hand, after being impregnated into reinforcing fibers at the manufacturing site of fiber reinforced thermoplastics (FRTP), it is Thermal melting (heating and melting) is a resin that rapidly polymerizes and can be converted into a high molecular weight thermoplastic resin.

Thermoplastic resin is a material that can be easily molded by being plasticized by heating. However, thermoplastic resins generally have a high molecular weight and have a high melt viscosity, so high temperature and high pressure are required for molding. It is not easy to become a small space or compound with materials that are difficult to heat or pressurize.

In view of this problem, Patent Document 1 proposes a method for producing an in-situ polymerization-type thermoplastic epoxy resin using a bifunctional epoxy resin and a bifunctional hardener. According to this technology, since a low molecular weight resin is used, impregnation is easy, and a thermoplastic fiber-reinforced plastic with few pores can be provided. However, on the other hand, the compound described with crystallinity can be diluted to such an extent that crystallinity does not occur, and in the only example, 90 parts by weight of the raw materials shown in Table 1 were also used. parts of organic solvent. Although crystalline compounds are also exemplified in epoxy resins and phenol compounds, techniques for suppressing crystallization while reducing organic solvents are desired.

In Non-Patent Document 1, it is disclosed that, in the in-situ polymerization type thermoplastic epoxy resin, the glass transition temperature (Tg) of the polymer is controlled by changing the skeleton of the main chain according to the type of epoxy resin or phenol compound. However, here, further studies have not been conducted on materials that change the skeleton of the main chain. According to the study by the inventors of the present invention, when a material having a low purity of the raw material is used, there are problems that the molecular weight does not increase, or that gelation occurs before construction on site. As a method of industrially improving the purity, distillation or recrystallization can be used. However, distillation has a problem that the yield per unit time decreases as the purity increases. The recrystallization requires relatively high crystallinity, so it is used in a system that contains almost no solvent. In the case of a phenolic compound with high crystallinity, it is difficult to uniformly dissolve in the epoxy resin and hold it stably. Since the phenolic compound is precipitated before the step of impregnating the carbon fiber, the designed molar ratio cannot be realized microscopically at the time of impregnation. As a result, there is a problem that a sufficient molecular weight is sometimes not obtained.

On the other hand, Patent Document 2 discloses a method of producing a crystalline adduct of both of which the melting point is lowered by heating and cooling a mixture of bisphenol A and bisphenol TMC. Only the melting point of the bisphenol crystalline adduct is disclosed, and there is no description about the application to epoxy resins, especially in-situ polymerization thermoplastic epoxy resins. [Prior Art Literature] [Patent Literature]

[Patent Document 1] WO2004/060981 [Patent Document 2] Japanese Patent Laid-Open No. 9-059196 [Non-patent literature]

[Non-Patent Document 1] "General Discussion on Epoxy Resins (Recent Progress I)", p422-p430 (Epoxy Resin Technology Association)

An object of the present invention is to provide an epoxy resin composition and a precursor thereof that can obtain an in-situ polymerization-type thermoplastic fiber-reinforced plastic having excellent heat resistance even with no solvent or a small amount of solvent, and which can be produced by a hot melt method. mixture.

Efforts have been made to solve the above-mentioned problems, and as a result, it has been found that after melting two or more phenol compounds, adding an epoxy resin, rapidly cooling it, and then mixing a polymerization catalyst, it is possible to provide a substantially less The epoxy resin composition in the B-stage state that undergoes a polymerization reaction and does not require curing in the subsequent steps can further provide an in-situ polymerization-type thermoplastic epoxy resin excellent in heat resistance.

That is, the present invention is a precursor mixture for use in an in-situ polymerized thermoplastic epoxy resin obtained by addition polymerization of a difunctional epoxy resin and a difunctional phenolic compound, characterized in that : Contains two or more difunctional phenolic compounds as essential components, the sum of the difunctional phenolic compounds is 0.9 mol to 1.1 mol relative to 1 mol of the difunctional epoxy resin, and the viscosity at 60°C is 1 Pa·s More than 50 Pa·s or less.

The precursor mixture preferably does not contain a solvent, or even if it contains a solvent, the solvent is 10 parts by weight or less relative to 100 parts by weight of the total amount of the bifunctional epoxy resin and the bifunctional phenolic compound. The haze value in the thickness direction when the precursor mixture is made into a thickness of 2 mm is preferably less than 30%.

The two or more difunctional phenolic compounds are preferably selected from the group consisting of bisphenol compounds and biphenolic compounds, and the ratio of the largest component in the two or more difunctional phenolic compounds is preferably 90% by weight Hereinafter, at least one of the two or more difunctional phenol compounds preferably has a melting point of 160°C or higher. In addition, since the phenol compound needs to be melted at a high temperature, the vapor pressure of the bifunctional phenol compound is preferably 0.01 Pa or less at 25°C.

The present invention is an epoxy resin composition, which is prepared by preparing a polymerization catalyst for the precursor mixture. The epoxy resin composition preferably uses 0.05% by weight to 5.0% by weight of a polymerization catalyst relative to the total amount of the bifunctional epoxy resin and the bifunctional phenol compound, without using a solvent, or using a A polymerization catalyst is prepared in the precursor mixture in an amount equal to or less than 2 times the amount of the solvent.

When the epoxy resin composition has a thickness of 2 mm, the haze value in the thickness direction is preferably less than 30%, and the viscosity at 60°C is preferably 3 Pa·s or more and 150 Pa·s or less.

The present invention is an epoxy resin composition sheet, which is obtained by making the epoxy resin composition into a thickness of 10 μm or more and 300 μm or less.

The present invention is an in-situ polymerization thermoplastic epoxy resin, which is obtained by polymerizing the epoxy resin composition; or a sheet-like in-situ polymerization thermoplastic epoxy resin, which is made by polymerizing the epoxy resin The composition sheet is polymerized.

The present invention is a prepreg, which is a prepreg obtained from the epoxy resin composition and/or the epoxy resin composition sheet and reinforcing fibers, and is an in-situ polymerized thermoplastic fiber Reinforced plastic, which is obtained by polymerizing the prepreg.

The precursor mixture for the in-situ polymerization type thermoplastic epoxy resin of the present invention does not precipitate crystals of the phenolic compound even if it is cooled to room temperature after mixing. The components can also be impregnated uniformly without being filtered out by the fibers, thereby obtaining an epoxy resin composition of stable polymerization quality.

Hereinafter, the present invention will be described in detail based on its preferred embodiments. The in-situ polymerization thermoplastic epoxy resin is obtained by addition polymerization of a difunctional epoxy resin and a difunctional phenolic compound, and is used in the precursor mixture (sometimes referred to as the in-situ polymerization thermoplastic epoxy resin) of the present invention. As a precursor) contains two or more difunctional phenolic compounds as essential components. The bifunctional phenol compound is a compound having two phenolic hydroxyl groups in one molecule, and its purity is preferably 95% by weight or more. Moreover, if the purity as a bifunctional compound is high, a positional isomer may be included. When a monofunctional impurity is contained, since the molecular weight after polymerization does not increase, there is a possibility that the mechanical properties of the produced thermoplastic resin may be deteriorated. Therefore, the amount of monofunctional impurities is preferably 2% by weight or less with respect to the bifunctional phenol compound. When an impurity of trifunctional or more is contained, since it is easy to form a cross-linked structure from the impurity as a starting point, in addition to the possibility that the dispersion of the polymer may be increased, there is a possibility that the thermoplasticity may be deteriorated by gelation. Therefore, it is preferable that it is 1 weight% or less with respect to a bifunctional phenol compound with respect to a trifunctional or more impurity. Furthermore, regarding the impurity component which does not have an active group that reacts with either epoxy resin or phenolic hydroxyl group, and does not inhibit the polymerization reaction when it is a simple substance, if the amount increases, the molecular weight after polymerization may also decrease. . Therefore, it is preferable that it is 2 weight% or less with respect to a bifunctional phenol compound.

In order to improve the heat resistance of the in-situ polymerized thermoplastic epoxy resin, it is desirable to employ a rigid structure. However, in order to obtain a rigid structure, the molecule itself becomes large, and thus the viscosity of the precursor mixture becomes high. The viscosity of the precursor mixture at 60° C. is preferably 1 Pa·s or more and 50 Pa·s or less in order to be processed by hot melt. When the viscosity is less than 1 Pa·s, the resin component in the epoxy resin composition sheet or the prepreg to be described later becomes too soft, and thus the handleability around room temperature deteriorates. In addition, when the viscosity exceeds 50 Pa·s, it is necessary to set a high temperature in the step of coating a substrate such as release paper or a release film or the step of impregnating the reinforcing fiber, so there is a possibility of affecting the storage stability. question. Therefore, the molecular weights of the two or more difunctional phenol compounds are preferably 500 or less. Moreover, it is preferable that the weight average molecular weight (Mw) as a mixture of two or more types is 320 or less.

The two or more difunctional phenol compounds are preferably selected from bisphenol compounds or biphenol compounds. Examples of the bisphenol compound include bisphenol A, bisphenol F (above, manufactured by NIPPON STEEL Chemical & Material Co., Ltd.), bisphenol fluorene, and biscresol fluorene (above, Osaka Gas Chemical (manufactured by Osaka Gas Chemical Co., Ltd.), Bis-E, Bis-Z, BisOC-FL, BisP-AP, BisP-CDE, BisP-HTG, BisP-MIBK, BisP-3MZ, S-BOC, Bis25X- F (the above, manufactured by Honshu Chemical Industry Co., Ltd.), bisphenol S, tetramethylbisphenol S, etc. As a biphenol compound, a biphenol, a dimethyl biphenol, a tetramethyl biphenol etc. are mentioned, for example. Examples of other bifunctional phenol compounds include hydroquinone, methyl hydroquinone, dibutyl hydroquinone, resorcinol, methylresorcinol, catechol, methylbenzene Hydroquinones such as catechol, or naphthalenediols such as naphthalenediol, and the like.

The bifunctional phenol compound is a mixture obtained by mixing two or more of the exemplified bifunctional phenol compounds. By mixing two or more types of bifunctional phenol compounds, it is possible to suppress precipitation of the bifunctional phenol compound at the time of normal temperature storage in the epoxy resin composition.

The content of the largest bifunctional phenol compound is preferably 90% by weight or less, more preferably 80% by weight or less, based on the total amount of the two or more difunctional phenol compounds. The melting point of at least one of the two or more bifunctional phenol compounds is preferably 160°C or higher, more preferably 200°C or higher. In addition, the melting point of all the bifunctional phenolic compounds is desirably 150°C or higher.

The bifunctional epoxy resin used in the epoxy resin composition of the present invention is a resin having two epoxy groups in one molecule, and its purity is preferably 95% or more. Moreover, if the purity as a bifunctional compound is high, a positional isomer or an oligomer may be included. When a monofunctional impurity is contained, since the molecular weight after polymerization does not increase, there is a possibility that the mechanical properties of the produced thermoplastic resin may be deteriorated. Therefore, the amount of monofunctional impurities is preferably 2% by weight or less with respect to the bifunctional epoxy resin. When an impurity of trifunctional or more is contained, since it is easy to form a cross-linked structure from the impurity as a starting point, in addition to the possibility that the dispersion of the polymer may be increased, there is a possibility that the thermoplasticity may be deteriorated by gelation. Therefore, it is preferable that it is 1 weight% or less with respect to a bifunctional epoxy resin with respect to the impurity of trifunctional or more. Furthermore, regarding the impurity component which does not have an active group that reacts with either epoxy resin or phenolic hydroxyl group, and does not inhibit the polymerization reaction when it is a simple substance, if the amount increases, the molecular weight after polymerization may also decrease. . Therefore, it is preferable that it is 2 weight% or less with respect to a bifunctional epoxy resin.

As bifunctional epoxy resins, for example, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, bisphenol acetophenone-type epoxy resins, and diphenyl sulfide are mentioned. bisphenol type epoxy resin, diphenyl ether type epoxy resin, tetramethyl bisphenol F type epoxy resin, bisphenol fluorene type epoxy resin, biscresol fluorene type epoxy resin and other bisphenol type epoxy resin, or Biphenol type epoxy resin such as tetramethyl biphenol type epoxy resin, diphenyldicyclopentadiene type epoxy resin, alkanediol type epoxy resin, dihydroxynaphthalene type epoxy resin, dihydroxybenzene type epoxy resin Epoxy resin and the like, but not limited to these. It is preferable to use the bifunctional epoxy resin which has an epoxy equivalent in the range of 150 g/eq to 350 g/eq.

In the precursor mixture of the present invention, regarding the blending ratio of the bifunctional epoxy resin and the bifunctional phenolic compound, the sum of the bifunctional phenolic compounds is 0.9 mol to 1.1 mol relative to 1 mol of the bifunctional epoxy resin. , preferably 0.95 mol to 1.05 mol, more preferably 0.96 mol to 1.04 mol, further preferably 0.97 mol to 1.03 mol. It is preferable that the molecular weight of the in-situ polymerization type thermoplastic epoxy resin obtained is sufficiently extended that the compounding ratio of the bifunctional phenol compound is within this range.

In the precursor mixture, the organic solvent is not an essential component. It is preferably 10 parts by weight or less with respect to 100 parts by weight of the total amount of the bifunctional epoxy resin and the bifunctional phenolic compound. More preferably, it is 5 parts by weight or less, and desirably not contained. Moreover, when using an organic solvent, it is preferable that the boiling point of an organic solvent in 1 atmospheric pressure is 200 degrees C or less.

The mixing conditions of the precursor mixture depend on the melting point of the bifunctional phenol compound to be used, but it is preferably melted at 200° C. or lower. Alternatively, the bifunctional phenol compound may be melted in advance at 300°C or lower, preferably 200°C or lower, and the bifunctional epoxy resin may be added at this time, rapidly cooled, and mixed at 150°C or lower.

It is desirable that the precursor mixture is completely melted at a temperature below 200°C. The precursor mixture was placed in a glass petri dish so as to have a thickness of 2 mm in a state without air bubbles, and if the haze value (turbidity) in the thickness direction was less than 30%, it was judged to be melted to 2 mm. Does not affect the level of polymerization. About the haze value, it is more preferable that it is less than 20%, and it is still more preferable that it is less than 10%.

The viscosity of the precursor mixture at 60° C. is 1 Pa·s or more and 50 Pa·s or less. When the viscosity is less than 1 Pa·s, the precursor mixture of the thermoplastic epoxy resin and its subsequent materials become too soft, and thus the handleability around room temperature may be deteriorated. In addition, when the viscosity exceeds 50 Pa·s, the workability at the time of preparing the polymerization catalyst in the next step may be deteriorated, or the storage stability may be deteriorated due to the need for treatment at high temperature. A more preferable viscosity is 3 Pa·s or more and 40 Pa·s or less, and preferably 5 Pa·s or more and 30 Pa·s or less. Furthermore, the precursor mixture is in a viscous liquid or solid state at room temperature.

The weight average molecular weight of the precursor mixture obtained from a standard polystyrene calibration curve is preferably 300 or more and 500 or less. The more preferable weight average molecular weight is 300 or more and 450 or less, and 300 or more and 400 or less are desirable. By setting the weight average molecular weight within the range, the viscosity of the precursor mixture at 60° C. can easily be set within a preferable range.

The precursor mixture of the present invention is prepared as an epoxy resin composition by preparing a polymerization catalyst. As the polymerization catalyst used in the epoxy resin composition, well-known and conventional ones can be used, and a phosphine compound is preferable. Specifically, phosphorus-based polymerization catalysts such as triphenylphosphine, tri-p-tolylphosphine, tri-o-tolylphosphine, and tri-p-methoxyphenylphosphine can be mentioned. As a polymerization catalyst other than this, an imidazole compound is mentioned, Specifically, TBZ, 1B2MZ, 1B2PZ, etc. are mentioned. The polymerization catalyst is preferably 0.05% by weight or more and 5.0% by weight or less with respect to the total amount of the bifunctional epoxy resin and the bifunctional phenol compound. It is more preferably 3.0% by weight or less, still more preferably 2.0% by weight or less, and particularly preferably 1.0% by weight or less. When the content is less than 0.05% by weight, the in-situ polymerization may take time, and the productivity may decrease, and there may be a possibility of deactivation for some reasons before reaching the target molecular weight. When it exceeds 5.0% by weight, the hardening reaction proceeds rapidly, and on the other hand, the storage stability may be impaired and the process suitability may be problematic. In addition to the possibility of impairing the physical properties after polymerization, since it is simply expensive, there is no economic benefit.

The polymerization catalyst is added and mixed into the precursor mixture after being dissolved in an organic solvent as needed. The organic solvent to be used is not particularly limited as long as it does not inhibit the reaction between the epoxy resin and the phenol compound, but hydrocarbon-based, ketone-based, and ether-based are preferred in terms of ease of acquisition. Specifically, toluene, xylene, acetone, methyl ethyl ketone, isobutyl ketone, cyclopentanone, cyclohexanone, diethylene glycol dimethyl ether, etc. are mentioned. Among them, even if the organic solvent does not participate in the reaction, if it is contained in a large amount in the epoxy resin composition of the in-situ polymerization type, the epoxy resin and the phenol compound will be diluted, so if the amount increases, the molecular weight after polymerization may decrease. Therefore, the amount of the organic solvent is preferably 2 times or less of the amount of the polymerization catalyst. In other words, it is preferable to use it as a polymerization catalyst solution containing 33% by weight or more of the polymerization catalyst as an active ingredient. Furthermore, as long as the polymerization catalyst can be uniformly mixed in the bifunctional epoxy resin and the bifunctional phenol compound, an organic solvent may not be used.

The epoxy resin composition of the present invention can be stored at room temperature or under refrigeration. As with the precursor mixture, the epoxy resin composition preferably has a haze value of less than 30% in the thickness direction when the thickness is 2 mm. The epoxy resin composition of the present invention does not necessarily contain a solvent, and even if it contains a small amount, crystallization can be suppressed by blending two or more types of bifunctional phenol compounds. The viscosity at 60°C is 3.0 Pa·s to 150 Pa·s. It is preferably 4 Pa·s or more and 100 Pa·s or less, and desirably 5 Pa·s or more and 80 Pa·s or less. When the viscosity is less than 3.0 Pa·s, the resin component in the epoxy resin composition sheet or the prepreg to be described later becomes too soft, and thus the handleability around room temperature may be deteriorated. In addition, when the viscosity exceeds 150 Pa·s, the step of applying to the film or the step of impregnating the reinforcing fiber needs to be high temperature, which may affect the storage stability.

The in-situ polymerization type epoxy resin composition of the present invention is a composition that contains two or more types of bifunctional phenolic compounds, a bifunctional epoxy resin, and a polymerization catalyst as essential components, and can be polymerized by heating . Additives may be included therein. Examples of additives include fillers such as fumed silica, flame retardants such as aluminum hydroxide and red phosphorus, modifiers such as core-shell rubber, and the like. From the viewpoint of stabilizing the polymerization reaction, it is desirable that the additive formulation is different from the resin phase, and within the range that does not affect the reaction, an organic solvent such as a dissolving aid or a viscosity modifier, or a plasticizer, Compatible flame retardant.

The epoxy resin composition sheet (sometimes referred to as a composition sheet) of the present invention is one obtained by applying the epoxy resin composition to a release-treated paper or plastic film, and optionally including a release-treated cover film . As for the mold release paper, the mold release plastic film, and the cover film, well-known and conventional ones can be used, and there are no particular limitations. The thickness of the epoxy resin composition sheet is determined by the design thickness of the prepreg and the resin ratio, and the usual thickness is 10 μm or more and 300 μm or less. When the thickness is less than 10 μm, if the reinforcing fibers are not defibrated smoothly, there is a problem that the mesh of the fibers becomes obvious, and when the thickness exceeds 300 μm, it is difficult to impregnate the reinforcing fibers uniformly. It is preferably 15 μm or more and 150 μm or less, and more preferably 20 μm or more and 100 μm or less.

The reinforcing fibers used in the present invention are fibers for reinforcing plastic, such as carbon fibers, polyaramid fibers, and cellulose fibers, and are not particularly limited. Moreover, regarding the form of a fiber, the unidirectional (unidirectional, UD) sheet|seat in which the fiber was aligned, a woven fabric, a tow, a chopped fiber, a nonwoven fabric, a papermaking, etc. are mentioned, It does not specifically limit. Among them, from the viewpoint of impregnation, the thickness of each fiber bundle is 1 mm or less, preferably 0.5 mm or less, and more preferably 0.2 mm or less.

The prepreg of the present invention is obtained from an epoxy resin composition and/or an epoxy resin composition sheet and reinforcing fibers. The ratio of the reinforcing fiber to the resin is 2:8 to 7:3 in volume ratio, preferably 5:5 to 7:3. When the ratio of the reinforcing fibers is less than 2, since the amount of the reinforcing fibers is reduced, there is a possibility that the strength required for the fiber-reinforced material cannot be sufficiently satisfied. When it exceeds 7, there is a possibility that the resin is insufficient and the voids may increase. If the voids remain during the impregnation, there is a possibility that the final product may be defective and the desired strength cannot be exhibited. Therefore, it is desirable to reduce the voids during the impregnation. As the method, heat treatment or pressure treatment can be performed. The heat treatment is usually performed at 50°C or higher and 100°C or lower. When the temperature is lower than 50°C, the viscosity of the resin cannot be sufficiently reduced, and impregnation failure may occur. When it exceeds 100 degreeC, a polymerization reaction may progress. The time of heat treatment is usually 5 seconds or more and 3 minutes or less. In the case of less than 5 seconds, there is a possibility that the viscosity reduction and impregnation may not be sufficiently performed depending on the thickness. When it exceeds 3 minutes, there exists a possibility that a polymerization reaction may advance a little, and the desired viscosity may not be obtained. As a method of further improving the impregnation accuracy, thermocompression bonding by a thermocompressor, a thermoroll, or the like is exemplified. Although the pressure also depends on the base material, it is 0.01 MPa or more and 1 MPa or less. When the pressure is less than 0.01 MPa, the impregnation may become insufficient, and when the pressure exceeds 1 MPa, the reinforcing fibers may be damaged or the resin may flow out.

In the case of using the in-situ polymerization type thermoplastic epoxy resin of the present invention, the in-situ polymerization type thermoplastic fiber can be obtained by, for example, polymerizing under the conditions of a temperature of 150° C. to 200° C. and a pressure of 0.1 MPa or more and 1.0 MPa or less. Reinforced plastic. Regarding the in-situ polymerization type thermoplastic epoxy resin of the present invention, in the in-situ polymerization type thermoplastic fiber-reinforced plastic, the weight average molecular weight (Mw) is preferably 35,000 to 150,000, more preferably 50,000 to 100,000. The dispersion (weight average molecular weight/number average molecular weight) is preferably 1 or more and 20 or less, more preferably 2 or more and 15 or less. When the dispersion exceeds 20, there is a tendency to easily gel. Furthermore, the dispersion will not be less than 1. In addition, the glass transition temperature (Tg) exhibited physical properties of 100°C to 130°C. [Example]

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by these examples at all. Unless otherwise specified, "parts" means parts by weight, and "%" means % by weight. In addition, the raw materials used in the following examples are as follows.

[Phenolic compound] A1: Bisphenol A (manufactured by NIPPON STEEL Chemical & Material Co., Ltd., molecular weight 228, melting point 158°C) A2: 4,4'-(3,3,5-trimethylcyclohexylene) bisphenol (manufactured by Honshu Chemical Industry Co., Ltd., BisP-HTG, molecular weight 310, melting point 206°C) A3: 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (manufactured by Osaka Gas Chemical Co., Ltd., molecular weight 378, melting point 217°C)

[Epoxy resin] B1: Bisphenol A type liquid epoxy resin (manufactured by NIPPON STEEL Chemical & Material Co., Ltd., YD-128, epoxy equivalent 188 g/eq) B2: Tetramethylbisphenol F-type epoxy resin (manufactured by NIPPON STEEL Chemical & Material Co., Ltd., YSLV-80XY, epoxy equivalent 192 g/eq) B3: Tetramethylbiphenol-type epoxy resin (manufactured by Mitsubishi Chemical Co., Ltd., YX4000, epoxy equivalent 188 g/eq)

[polymerization catalyst] C1: Tris(p-methoxyphenyl)phosphine (manufactured by Beixing Chemical Industry Co., Ltd., TPAP)

[reinforced fiber] I1: PAN-based carbon fiber (manufactured by Toray Co., Ltd., T700SC-12K-60E)

Example 1 150 parts of A1 and 50 parts of A2 were placed in a separable flask including a stirrer, a thermocouple, a nitrogen gas inlet, and a nitrogen gas outlet, and the temperature was raised while stirring so that the powder did not fly without using a solvent. Since A1 started to melt from the vicinity of the internal temperature exceeding 150°C, and A2 was melted at 180°C and became uniform, 317 parts of B1 at 40°C was added thereto and mixed while cooling the inside of the system. Furthermore, it cooled to 50 degreeC, stirring, and obtained the homogeneous liquid precursor mixture. The appearance of the obtained precursor mixture was evaluated, and the result was ○, and the viscosity at 60° C. was measured using CV-1s manufactured by Toa Kogyo Co., Ltd., and the result was 2 Pa·s. 100 parts of the precursor mixture was weighed, and 2 parts of a 50% C1 catalyst solution previously dissolved in cyclohexanone was added and mixed to obtain an epoxy resin composition. The appearance of the obtained epoxy resin composition was evaluated, and the result was ○, and the viscosity at 60° C. was measured using MCR102 manufactured by Anton Paar, and the result was 5 Pa·s. The evaluation of the appearance was performed by visual observation, and the case where the insoluble matter was precipitated in the sample was taken as ×, the sample was taken into a petri dish so that the thickness of the sample was 2 mm, and the haze value was determined as The case of 30% or more was made into Δ, and the case of less than 30% of the haze value was made into ○.

Using a preheated bar coater at 80° C., the obtained epoxy resin composition was coated on a silicone-coated release paper with a thickness of 50 μm. Thereon, it protected with the coverlay film made of polyethylene, and obtained the epoxy resin composition sheet. The peelability of the obtained epoxy resin composition sheet was evaluated, and the result was ○. In addition, the evaluation of the peelability of the composition sheet was based on the presence or absence of transfer of the resin to the cover film peeled from the epoxy resin composition sheet and the presence or absence of defects such as cracks in the sheet itself in a state of 23°C x 50% RH. to evaluate. When there was no transfer of resin and sheet defects, the evaluation of releasability was made ○, and when there was transfer of resin or defects of sheets, the evaluation of releasability was made into x.

Next, peeling of the cover film was performed from the obtained epoxy resin composition sheet, and carbon fibers (I1) were attached to the peeled resin surface so as to have a strand density of 15 per 10 cm, and preheating was used. A hot press at 90° C. applied pressure so that the surface pressure was 0.5 MPa, and after 1 minute, it was taken out and air-cooled to obtain an epoxy resin prepreg with Rc=33%. The peelability of the obtained prepreg was evaluated, and the result was ○. In addition, the evaluation of the prepreg peeling property was performed based on the presence or absence of resin transfer to the release paper peeled from the prepreg in the state of 23° C.×50% RH. When there was no transfer of resin, the evaluation of releasability was made ○, and when there was transfer of resin, evaluation of releasability was made of ×. In addition, the viscosity of the obtained prepreg was evaluated, and the result was ○. In addition, the evaluation of the tackiness is based on whether the prepregs can be peeled off without disturbing the fibers when the prepregs are lightly overlapped with each other in the state of 23°C x 50%RH, and whether they appear after being lightly pressed with a roller. The adhesiveness of the peeling is judged. In addition, "lightly overlapping" means bonding only by the self-weight of the prepreg, and "lightly pressing with a roller" means bonding the prepreg using a 500 g roller. When it is lightly overlapped, it can be peeled off without disturbing the fibers, and when it is lightly pressed with a roller and exhibits adhesiveness that does not fall off, the adhesiveness is set to ○, and when it is lightly overlapped, the adhesion is too strong. , or when it does not stick even if it is lightly pressed with a roller, the stickiness is set to ×.

The release paper of the prepreg was peeled off in a state of 23° C.×50% RH. The prepreg was laminated in four layers of 0/90/90/0, and the obtained laminated body was polymerized under the conditions of a pressing pressure of 0.5 MPa and 160° C.×1 hour to obtain a laminated board. Regarding the obtained laminate, the weight-average molecular weight (Mw) of the in-situ polymerized thermoplastic epoxy resin was 76,000. In addition, the measuring method of Mw is as follows. Analysis was performed using HLC-8320GPC manufactured by Tosoh Co., Ltd. The column was connected in series with TSKguardcolumnHXL, TSKgel GMHXL, TSKgel GMHXL and TSKgel G2000HXL, and the column oven was set to 40°C. The eluate was set to tetrahydrofuran, and the detector was set to an RI detector. Regarding the flow rate, it was set to 1 mL/min on the sample side and 0.5 mL/min on the reference side. Weigh about 0.1 g of the laminate, dissolve it in 10 mL of tetrahydrofuran containing 5% cyclohexanone as an external standard material, and filter it with a 0.45 μm polytetrafluoroethylene (PTFE) membrane filter. for analysis. The molecular weight was converted using a standard polystyrene calibration curve, and the dissolution time was corrected using cyclohexanone. In addition, the glass transition temperature (Tg) of the thermoplastic fiber-reinforced plastic is 100°C. In addition, the measuring method of Tg is as follows. According to Japanese industrial standard (JIS) K 7121, using a differential scanning calorimeter (Hitachi High-Tech Science Co., Ltd., EXSTAR6000 DSC6200) under the condition of heating at 10℃/min The measurement is represented by the temperature of DSC·Tmg (the middle temperature of the variation curve with respect to the tangent line between the glass state and the rubber state) at this time.

Example 2 In the same apparatus as in Example 1, 100 parts of A1 and 100 parts of A2 were charged, and the temperature was raised until the contents were melted while stirring so that the powder did not fly. Since A1 started to melt from the vicinity of the inner temperature exceeding 150°C, and A2 was melted at 190°C and became uniform, 295 parts of B1 at 40°C was added thereto and mixed while cooling the inside of the system. Furthermore, it cooled to 50 degreeC, stirring, and obtained the homogeneous precursor mixture. Using the obtained precursor mixture, the same operation as in Example 1 was performed to obtain an epoxy resin composition, an epoxy resin composition sheet, a prepreg, and a laminate. The obtained laminate was measured in the same manner as in Example 1.

Example 3 In the same apparatus as Example 1, 50 parts of A1 and 150 parts of A2 were charged, and the temperature was raised until the contents were melted while stirring so that the powder did not fly. From the vicinity of the inner temperature exceeding 150°C, A1 began to melt, and A2 melted and became uniform at 200°C, so 272 parts of B1 at 40°C were added thereto and mixed while cooling the inside of the system. Furthermore, it cooled to 50 degreeC, stirring, and obtained the homogeneous precursor mixture. Using the obtained precursor mixture, the same operation as in Example 1 was performed to obtain an epoxy resin composition, an epoxy resin composition sheet, a prepreg, and a laminate. The obtained laminate was measured in the same manner as in Example 1.

Example 4 In the same apparatus as in Example 1, 100 parts of A1 and 100 parts of A2 were charged, and the temperature was raised until the contents were melted while stirring so that the powder did not fly. Since A1 started to melt from the vicinity of the internal temperature exceeding 150°C, and A2 melted and became uniform around 190°C, 301 parts of B2 at room temperature was added and mixed, and the inside of the system was cooled. Further, stirring was performed to confirm the melting of B2, and the mixture was cooled to 50° C. to obtain a uniform liquid precursor mixture. Using the obtained precursor mixture, the same operation as in Example 1 was performed to obtain an epoxy resin composition, an epoxy resin composition sheet, a prepreg, and a laminate. The obtained laminate was measured in the same manner as in Example 1.

Example 5 In the same apparatus as in Example 1, 100 parts of A1 and 100 parts of A2 were charged, and the temperature was raised until the contents were melted while stirring so that the powder did not fly. Since A1 started to melt from the vicinity of the internal temperature exceeding 150°C, and A2 melted and became uniform around 190°C, 294 parts of B3 at room temperature was added thereto and mixed while cooling the inside of the system. Furthermore, stirring was performed to confirm the melting of B3, and the mixture was cooled to 50° C. to obtain a uniform liquid precursor mixture. Using the obtained precursor mixture, the same operation as in Example 1 was performed to obtain an epoxy resin composition, an epoxy resin composition sheet, a prepreg, and a laminate. The obtained laminate was measured in the same manner as in Example 1.

Example 6 In the same apparatus as Example 1, 150 parts of A1, 25 parts of A2, and 25 parts of A3 were charged, and the temperature was raised until the contents were melted while stirring so that the powder did not fly. A1 starts to melt from the vicinity of the internal temperature exceeding 150°C, and A2 and A3 melt and become uniform around 190°C. Therefore, 69 parts of B1 at room temperature and 228 parts of B3 are added and mixed. Cool down. Furthermore, stirring was performed, the melting of B1 and B3 was confirmed, and the mixture was cooled to 50° C. to obtain a uniform liquid precursor mixture. Using the obtained precursor mixture, the same operation as in Example 1 was performed to obtain an epoxy resin composition, an epoxy resin composition sheet, a prepreg, and a laminate. The obtained laminate was measured in the same manner as in Example 1.

Comparative Example 1 In the same apparatus as in Example 1, 200 parts of A1 were charged, and the temperature was raised until the contents were melted while stirring so that the powder did not fly. Since A1 melted from the vicinity of the inner temperature exceeding 155°C and became uniform around 160°C, 340 parts of B1 at 40°C were added thereto and mixed while cooling the inside of the system. Initially, a homogeneous liquid mixture was obtained, but precipitation occurred during cooling to 50°C, and a cloudy precursor mixture was obtained. Using the obtained precursor mixture, the same operation as in Example 1 was performed to obtain an epoxy resin composition, an epoxy resin composition sheet, a prepreg, and a laminate. The obtained laminate was measured in the same manner as in Example 1.

Comparative Example 2 In the same apparatus as in Example 1, 200 parts of A2 was charged, and the temperature was raised while stirring so that the powder did not fly, and the temperature was raised until the contents were melted, but the temperature did not melt even when the internal temperature reached 200°C. Thereto, 250 parts of B1 at 40°C was added, while cooling the inside of the system. Furthermore, in the process of cooling to 50 degreeC while stirring, a cloudy precursor mixture was obtained. Using the obtained precursor mixture, the same operation as in Example 1 was performed to obtain an epoxy resin composition, an epoxy resin composition sheet, a prepreg, and a laminate. The obtained laminate was measured in the same manner as in Example 1.

[Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 A1 150 100 50 100 100 150 200 A2 50 100 150 100 100 25 200 A3 25 B1 317 295 272 69 339 249 B2 301 B3 294 228 Appearance Precursor Resin Composition 〇〇 〇〇 〇〇 〇〇 〇〇 〇〇 Δ Δ Δ Δ Viscosity (Pa·s) Precursor Resin Composition 2 5 3 8 5 15 12 35 11 32 16 41 - 3 1 2 Peelable composition sheet prepreg 〇〇 〇〇 〇〇 〇〇 〇〇 〇〇 × × × × sticky 〇 〇 〇 〇 〇 〇 × × Mw 76000 77000 90000 81000 67000 71000 69000 32000 Tg (℃) 100 109 117 106 122 113 90 123

In Example 1, when the molten mixture of BPA (A1) and BisP-HTG (A2) was directly put into the epoxy resin, and the system was cooled in this state, crystallization did not occur, A homogeneous resin mixture can be obtained. The same results were obtained in Example 2 and Example 3 in which the ratio of BPA to BisP-HTG was changed. As shown in Example 4 and Example 5, it was found that the same results were obtained even if the type of epoxy resin was changed. In Comparative Example 1 using BPA as a simple substance, reprecipitation of crystals was observed during cooling, and cloudiness occurred. Although it is thought that it was influenced by the seed crystals remaining in the flask a little, this phenomenon was not observed in Examples 1 to 6, and it was found that the quality of the molten state was stabilized by mixing and using the phenol compound. In addition, regarding the precursor mixture, it is thought that the re-precipitation of BPA is influenced by shearing, but since the measurement of the viscosity at 60°C is unstable, the result cannot be measured. In Comparative Example 2 using the simple substance of BisP-HTG, it did not melt even when heated to 200° C., and even when an epoxy resin was put in, it was not melted. Compared with other materials, this laminated board or resin board is not sufficiently polymerized. The reason is considered to be that when a rigid and high melting point phenolic compound is used alone, the phenolic compound does not melt even at the curing temperature, which adversely affects the polymerization reaction. That is, by mixing and using a phenol compound, the melting temperature can be effectively lowered, and the phenol compound having a rigid molecular structure can be used as a thermoplastic epoxy resin composition. From the above, even if it is a rigid phenolic compound with a high melting point, by melt-mixing with other phenolic compounds, the use of an organic solvent can be significantly reduced, and the organic solvent can be introduced into the skeleton of the in-situ polymerization type thermoplastic epoxy resin, thereby improving heat resistance. . In addition, by using a plurality of phenolic compounds, precipitation of crystals can be suppressed in the resin mixture, so that the degree of polymerization of the laminate can be increased. Furthermore, it was shown that the peelability and the tackiness can be adjusted with good productivity without performing the aging treatment or the like about the epoxy resin composition sheet or the prepreg. [Industrial Availability]

The precursor mixture of the present invention can be used in epoxy resin compositions (sheets), and can be particularly preferably used in in-situ polymerized thermoplastic epoxy resins, prepregs, thermoplastic fiber reinforced plastics, and the like.

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Claims (15)

A precursor mixture, which is a precursor mixture in an in-situ polymerized thermoplastic epoxy resin obtained by addition polymerization of a difunctional epoxy resin and a difunctional phenolic compound, characterized in that: Contains two or more difunctional phenolic compounds as essential components, the sum of the difunctional phenolic compounds is 0.9 mol to 1.1 mol relative to 1 mol of the difunctional epoxy resin, and the viscosity at 60°C is 1 Pa·s More than 50 Pa·s or less. The precursor mixture according to claim 1, wherein no solvent is contained, or even if a solvent is contained, the solvent is also 10 parts by weight relative to 100 parts by weight of the total amount of the difunctional epoxy resin and the difunctional phenolic compound the following. The precursor mixture of claim 1, wherein the haze value in the thickness direction when the thickness is 2 mm is less than 30%. The precursor mixture of claim 1, wherein the two or more difunctional phenolic compounds are selected from the group consisting of bisphenolic compounds and biphenolic compounds. The precursor mixture according to claim 1, wherein the ratio of the largest component in the two or more difunctional phenol compounds is 90% by weight or less. The precursor mixture according to claim 1, wherein at least one of the two or more difunctional phenolic compounds has a melting point of 160°C or higher. An epoxy resin composition prepared by mixing the precursor mixture according to any one of claim 1 to claim 6 with a polymerization catalyst, and being compatible with each other. The epoxy resin composition according to claim 7, wherein 0.05% by weight to 5.0% by weight of a polymerization catalyst is used with respect to the total amount of the bifunctional epoxy resin and the bifunctional phenolic compound, and no solvent is used, or The polymerization catalyst is prepared in the precursor mixture in an amount equal to or less than twice the amount of the polymerization catalyst. The epoxy resin composition according to claim 7, wherein the haze value in the thickness direction when the thickness is 2 mm is less than 30%. The epoxy resin composition according to claim 7, wherein the viscosity at 60° C. is 3 Pa·s or more and 150 Pa·s or less. A thermoplastic epoxy resin obtained by polymerizing the epoxy resin composition according to any one of Claims 7 to 10. An epoxy resin composition sheet obtained by making the epoxy resin composition according to any one of Claims 7 to 10 into a thickness of 10 μm or more and 300 μm or less. A sheet-like in-situ polymerized thermoplastic epoxy resin obtained by polymerizing the epoxy resin composition sheet according to claim 12. A prepreg obtained from the epoxy resin composition according to any one of claim 7 to claim 10 and/or the epoxy resin composition sheet according to claim 12, and reinforcing fibers . An in-situ polymerized thermoplastic fiber-reinforced plastic is obtained by polymerizing the prepreg described in claim 14.