CN116457397A - Precursor mixture for in-situ polymerizable thermoplastic epoxy resin, epoxy resin composition, epoxy resin composition sheet, prepreg, and in-situ polymerizable thermoplastic fiber-reinforced plastic using them - Google Patents

Abstract

The invention provides an epoxy resin composition and a precursor mixture thereof capable of obtaining an in-situ polymerized thermoplastic fiber reinforced plastic with excellent heat resistance and capable of being produced in a hot-melt manner. A precursor mixture for an in-situ polymerizable thermoplastic epoxy resin obtained by polyaddition of a difunctional epoxy resin and a difunctional phenolic compound, characterized in that it contains two or more difunctional phenolic compounds as essential components , the sum of the difunctional phenolic compounds is 0.9 to 1.1 mol with respect to 1 mol of the difunctional epoxy resin, and the viscosity at 60° C. is 1 Pa·s to 50 Pa·s.

Description

Precursor mixture for in-situ polymerization type thermoplastic epoxy resin, epoxy resin composition, Epoxy resin composition sheet, prepreg and in-situ polymerization type thermal plastic fiber reinforced plastic

technical field

The present invention relates to in-situ polymerized thermoplastic epoxy resins and thermoplastic fiber reinforced plastics. Here, the thermoplastic resin of the in-situ polymerization type refers to a low molecular weight when shipped from the factory, but after being impregnated with reinforcing fibers at the production site of fiber-reinforced thermoplastic (FRTP), it can be quickly polymerized and converted by thermal melting (heating and melting). A resin that is a high molecular weight thermoplastic resin.

Background technique

A thermoplastic resin is a material that has plasticity by heating and can be easily molded. However, thermoplastic resins generally have a high molecular weight and a high melt viscosity, so high temperature and high pressure are required for molding. It is not easy to compound materials that are difficult to heat and pressurize in a narrow space.

To address 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 curing agent. According to this technology, since a low-molecular-weight resin is used, impregnation is easy, and a thermoplastic fiber-reinforced plastic with few voids can be provided. However, on the other hand, it is described that crystalline compounds can be diluted to the extent that no crystallization occurs, and in the only example, 90 parts of organic solvent. Epoxy resins and phenolic compounds also exemplify crystalline compounds, but techniques for suppressing crystallization while reducing organic solvents are desired.

Non-Patent Document 1 discloses that the glass transition temperature (Tg) of the polymer is controlled by changing the skeleton of the main chain of an in-situ polymerizable thermoplastic epoxy resin according to the type of epoxy resin or phenol compound. However, the materials involved in the modified main chain backbone were not further studied here.

According to studies by the inventors of the present invention, when using low-purity raw materials, problems such as no increase in molecular weight or gelation before on-site construction occur. Distillation or recrystallization can be mentioned as a method of industrially improving the purity, but distillation has the problem that the yield per unit time decreases as the purity increases, and recrystallization requires high crystallinity, so crystallization is used in a system that contains almost no solvent. In the case of a phenolic compound with high solubility, it is difficult to dissolve uniformly in the epoxy resin and maintain it stably. Since the phenolic compound is precipitated before the step of impregnating the carbon fibers, the designed molar ratio cannot be achieved microscopically during the impregnation. As a result, there is a problem that a sufficient molecular weight may not be obtained.

On the other hand, Patent Document 2 discloses a method of heating and cooling a mixture of bisphenol A and bisphenol TMC to lower the melting point of both crystalline adducts. Only the melting point is disclosed for this bisphenol crystalline adduct, and there is no description about its application to epoxy resins, particularly in-situ polymerizable thermoplastic epoxy resins.

prior art literature

patent documents

Patent Document 1: WO2004/060981

Patent Document 2: Japanese Patent Application Laid-Open No. 9-059196

non-patent literature

Non-Patent Document 1: Review of Recent Advances in Epoxy Resins I, p422-p430 (Epoxy Resin Technology Association)

Contents of the invention

The object of the present invention is to provide an epoxy resin composition and its precursor which can obtain an in-situ polymerizable thermoplastic fiber-reinforced plastic which is excellent in heat resistance and can be produced by hot melt even without a solvent or a small amount of solvent. body mixture.

As a result of intensive research to solve the above-mentioned problems, it was found that after melting two or more kinds of phenolic compounds, adding an epoxy resin and rapidly cooling, and then mixing a polymerization catalyst, it is possible to provide An epoxy resin composition in a B-stage state that does not require aging in the process can provide an in-situ polymerizable thermoplastic epoxy resin excellent in heat resistance.

That is, the present invention is a precursor mixture characterized in that it is a precursor mixture for an in-situ polymerizable thermoplastic epoxy resin obtained by polyaddition of a difunctional epoxy resin and a difunctional phenolic compound,

Contains two or more types of difunctional phenolic compounds as essential components, the sum of the difunctional phenolic compounds is 0.9 to 1.1 moles per mole of the difunctional epoxy resin, and the viscosity at 60° C. is 1 Pa·s to 50 Pa·s.

It is preferable that the said precursor mixture does not contain a solvent, or when containing a solvent, it is preferable that the solvent is 10 weight part or less with respect to 100 weight part of total amounts of a bifunctional epoxy resin and a bifunctional phenol 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 above-mentioned two or more kinds of bifunctional phenolic compounds are preferably selected from bisphenol compounds and biphenol compounds, and the ratio of the largest component among the two or more kinds of bifunctional phenolic compounds is preferably 90% by weight or less. The two or more kinds of bifunctional phenolic compounds At least one of them preferably has a melting point of 160°C or higher. In addition, since the phenolic compound needs to be melted at high temperature, the vapor pressure of the difunctional phenolic compound is preferably 0.01 Pa or less at 25°C.

The present invention is an epoxy resin composition in which a polymerization catalyst is mixed with the above-mentioned precursor mixture. The epoxy resin composition preferably uses 0.05 to 5.0% by weight of a polymerization catalyst based on the total amount of the difunctional epoxy resin and the difunctional phenolic compound, and does not use a solvent, or uses a solvent in an amount equal to or less than twice the amount of the polymerization catalyst. , with a polymerization catalyst in the precursor mixture.

When the above-mentioned 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 to 150 Pa·s.

The present invention is an epoxy resin composition sheet having a thickness of 10 μm to 300 μm from the above epoxy resin composition.

The present invention is an in-situ polymerizable thermoplastic epoxy resin obtained by polymerizing the above epoxy resin composition, or a sheet-shaped in-situ polymerizable thermoplastic epoxy resin obtained by polymerizing the above epoxy resin composition sheet.

The present invention is a prepreg obtained from the above-mentioned epoxy resin composition and/or the above-mentioned epoxy resin composition sheet and reinforcing fibers, and is an in-situ polymerization type thermoplastic fiber-reinforced plastic 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 phenolic compounds even after mixing and cooling to room temperature, so even if a large amount of organic solvent is not used when impregnating carbon fibers, specific components can be eliminated. The epoxy resin composition of stable polymerization quality can be obtained by being filtered out by the fiber and impregnated uniformly.

Detailed ways

Hereinafter, the present invention will be described in detail based on its preferred embodiments.

The in-situ polymerizable thermoplastic epoxy resin is obtained by polyaddition of a difunctional epoxy resin and a difunctional phenolic compound, and the precursor mixture (sometimes referred to as a precursor) used in the in-situ polymerizable thermoplastic epoxy resin of the present invention contains Two or more kinds of difunctional phenol compounds are essential components.

The difunctional phenol compound is a compound having two phenolic hydroxyl groups in one molecule, and its purity is preferably 95% by weight or more. In addition, positional isomers may be included as long as the purity as a difunctional compound is high.

When a monofunctional impurity is contained, the molecular weight after polymerization does not increase, so the mechanical properties of the produced thermoplastic resin may deteriorate. Therefore, it is preferable that a monofunctional impurity is 2 weight% or less with respect to a difunctional phenol compound.

In the case where impurities having a trifunctional or higher function are contained, since a crosslinked structure is easily formed starting from the impurities, the dispersion of the polymer may increase, and gelation may proceed to impair thermoplasticity. Therefore, it is preferable that the impurity more than trifunctional is 1 weight% or less with respect to a difunctional phenol compound.

It should be noted that if the amount of impurity components that do not have an active group that reacts with both the epoxy resin and the phenolic hydroxyl group and do not hinder the polymerization reaction in the monomer, the molecular weight after polymerization may also decrease. Therefore, it is preferably 2% by weight or less with respect to the difunctional phenol compound.

In order to improve the heat resistance of the in-situ polymerization type thermoplastic epoxy resin, it is preferable to adopt a rigid structure. However, in order to achieve a rigid structure, the molecules themselves become larger and thus the viscosity of the precursor mixture becomes higher. For processing in a hot melt manner, the viscosity of the precursor mixture at 60° C. is preferably 1 Pa·s to 50 Pa·s. When the viscosity is less than 1 Pa·s, the epoxy resin composition sheet or the resin component in the prepreg which will be described later becomes too soft, so the handleability around room temperature deteriorates. In addition, when the viscosity exceeds 50 Pa·s, the process of coating on base materials such as release paper and release film and the process of immersing in reinforcing fibers need to be at high temperature, so there is a problem of affecting storage stability.

Therefore, it is preferable that the molecular weights of two or more types of bifunctional phenolic compounds are all 500 or less. Moreover, it is preferable that the weight average molecular weight (Mw) which is a mixture of 2 or more types is 320 or less.

Two or more types of difunctional phenol compounds are preferably selected from bisphenol compounds or biphenol compounds. Examples of bisphenol compounds include bisphenol A, bisphenol F (manufactured by Nippon Steel Chemical & Materials Co., Ltd.), bisphenol fluorene, biscresol fluorene (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 (manufactured by Honshu Chemical Industry Co., Ltd.), bisphenol S, tetramethylbisphenol S, etc. As a biphenol compound, biphenol, dimethyl biphenol, tetramethyl biphenol etc. are mentioned, for example. Examples of other difunctional phenolic compounds include hydroquinone, methylhydroquinone, dibutylhydroquinone, resorcinol, methylresorcinol, catechol, methyl Hydroquinones such as teaphenol, naphthalenediols such as naphthalene diol, and the like.

The bifunctional phenol compound is a mixture obtained by mixing two or more of the illustrated bifunctional phenol compounds. By mixing two or more types of bifunctional phenolic compounds, as an epoxy resin composition, precipitation of a bifunctional phenolic compound can be suppressed at the time of normal-temperature storage.

The content of the most difunctional phenolic compound is preferably 90% by weight or less, more preferably 80% by weight or less, based on the total amount of two or more types of bifunctional phenolic compounds.

The melting point of at least one bifunctional phenol compound among 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 difunctional phenol compounds is preferably 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. Furthermore, as long as the purity of the bifunctional compound is high, positional isomers and oligomers may be included.

When a monofunctional impurity is contained, the molecular weight after polymerization does not increase, so the mechanical properties of the produced thermoplastic resin may deteriorate. Therefore, it is preferable that a monofunctional impurity is 2 weight% or less with respect to a bifunctional epoxy resin.

In the case where impurities having a trifunctional or higher function are contained, since a crosslinked structure is easily formed starting from the impurities, the dispersion of the polymer may increase, and gelation may proceed to impair thermoplasticity. Therefore, it is preferable that the impurity more than trifunctional is 1 weight% or less with respect to a difunctional epoxy resin.

It should be noted that if the amount of impurity components that do not have an active group that reacts with both the epoxy resin and the phenolic hydroxyl group and do not hinder the polymerization reaction in monomers increases, the molecular weight after polymerization may also decrease. Therefore, it is preferably 2% by weight or less with respect to the bifunctional epoxy resin.

Examples of bifunctional epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, bisphenol acetophenone epoxy resins, and diphenyl sulfide epoxy resins. 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 resins, tetramethyl Biphenol-type epoxy resins such as biphenol-type epoxy resins, diphenyldicyclopentadiene-type epoxy resins, alkylene glycol-type epoxy resins, dihydroxynaphthalene-type epoxy resins, and dihydroxybenzene-type epoxy resins epoxy resins, etc., but not limited to them.

As the difunctional epoxy resin, an epoxy resin having an epoxy equivalent in the range of 150 to 350 g/eq can be preferably used.

In the precursor mixture of the present invention, with respect to the mixing ratio of the difunctional epoxy resin and the difunctional phenolic compound, the sum of the difunctional phenolic compounds is 0.9 to 1.1 moles, preferably 0.95 per mole of the difunctional epoxy resin. ~1.05 moles, more preferably 0.96~1.04 moles, even more preferably 0.97~1.03 moles. When the compounding ratio of a difunctional phenol compound exists in this range, since the molecular weight of the obtained in-situ polymerization type thermoplastic epoxy resin will fully increase, it is preferable.

In the precursor mixture, the organic solvent is not an essential ingredient. It is preferably 10 parts by weight or less with respect to 100 parts by weight of the total of the bifunctional epoxy resin and the bifunctional phenol compound. More preferably 5 parts by weight or less, preferably not contained. In addition, when an organic solvent is used, the boiling point of the organic solvent at 1 atmosphere is preferably 200° C. or lower.

The mixing conditions of the precursor mixture depend on the melting point of the difunctional phenolic compound used, but are preferably melted below 200°C. Alternatively, when the difunctional phenol compound is melted at 300°C or lower, preferably at 200°C or lower, the difunctional epoxy resin may be added, quenched, and mixed at 150°C or lower.

Preferably the precursor mixture melts completely at a temperature below 200°C. Put the precursor mixture in a glass petri dish so that it has a thickness of 2mm in a state without air bubbles, and if the haze value (turbidity) in the thickness direction is less than 30%, it is judged to be molten enough to not affect polymerization level of response. The haze value is more preferably less than 20%, still more preferably less than 10%.

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

The weight average molecular weight of the precursor mixture based on a standard polystyrene calibration line is preferably 300-500. More preferable weight average molecular weight is 300-450, Preferably it is 300-400. By setting the weight average molecular weight within the range, it is easy to make the viscosity of the precursor mixture at 60° C. within the preferable range.

The precursor mixture of the present invention is mixed with a polymerization catalyst to prepare an epoxy resin composition. As the polymerization catalyst used in the epoxy resin composition, known and commonly used polymerization catalysts can be used, but a phosphine compound is preferred. Specific examples thereof include phosphorus-based polymerization catalysts such as triphenylphosphine, tri-p-toluoylphosphine, tri-o-toluoylphosphine, and tri-p-methoxyphenylphosphine. Examples of other polymerization catalysts include imidazole compounds, specifically, TBZ, 1B2MZ, 1B2PZ, and the like. It is preferable that a polymerization catalyst is 0.05 weight% - 5.0 weight% with respect to the total sum total of a difunctional phenol compound and a difunctional phenol compound. More preferably, it is 3.0 weight% or less, More preferably, it is 2.0 weight% or less, Especially preferably, it is 1.0 weight% or less. If it is less than 0.05% by weight, the in-situ polymerization may take time, so the productivity may decrease, and inactivation may occur for some reason before reaching the target molecular weight. In the case of exceeding 5.0% by weight, the curing reaction proceeds rapidly. On the other hand, there is a possibility that the storage stability may be impaired to cause problems in process suitability. Since it is a component that participates in the reaction but is not incorporated into the skeleton, except for In addition to the possibility of impairing the physical properties after polymerization, it is also economically disadvantageous because it is simply expensive.

A polymerization catalyst is dissolved in an organic solvent as needed, and then added and mixed with the precursor mixture. 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 hydrocarbons, ketones, and ethers are preferable from the viewpoint of availability. Specifically, toluene, xylene, acetone, methyl ethyl ketone, isobutyl ketone, cyclopentanone, cyclohexanone, diglyme, etc. are mentioned. However, even if the organic solvent does not participate in the reaction, if it is contained in a large amount in the in-situ polymerization type epoxy resin composition, the epoxy resin and the phenol compound will be diluted, so if the amount increases, the molecular weight after polymerization may decrease , so the amount of the organic solvent is preferably 2 times or less relative to the polymerization catalyst. In other words, it is preferably used in the form of a polymerization catalyst solution in which the polymerization catalyst as an active ingredient is 33% by weight or more. In addition, if a polymerization catalyst can mix uniformly in a bifunctional phenolic compound and a difunctional phenolic compound, you may not use an organic solvent.

The epoxy resin composition of this invention can be stored at room temperature or under refrigeration. As with the precursor mixture, the epoxy resin composition preferably has a haze value in the thickness direction of less than 30% at a thickness of 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 difunctional phenol compounds. The viscosity at 60°C is 3.0 to 150 Pa·s. It is preferably 4 Pa·s to 100 Pa·s, preferably 5 Pa·s to 80 Pa·s. When the viscosity is less than 3.0 Pa·s, the epoxy resin composition sheet or the resin component in the prepreg described later becomes too soft, and thus the handling properties around room temperature may be deteriorated. In addition, when the viscosity exceeds 150 Pa·s, since the process of coating on the film and the process of impregnating the reinforcing fiber are required to be at high temperature, storage stability may be affected.

The in-situ polymerization-type epoxy resin composition of the present invention refers to a composition that contains two or more types of difunctional phenol compounds, a difunctional epoxy resin, and a polymerization catalyst as essential components, and can be polymerized by heating. It may contain additives. 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 preferable to mix additives different from the resin phase, but within the range that does not affect the reaction, organic solvents, plasticizers, and compatible barriers may be included as dissolution aids, viscosity adjustment, etc. Fuel.

The epoxy resin composition sheet (sometimes referred to as a composition sheet) of the present invention is formed by applying the epoxy resin composition to a release-treated paper or plastic film, and if necessary, includes a release-treated cover film. As the release paper, the release plastic film, and the cover film, known and commonly used films can be used without any particular limitation. The thickness of the epoxy resin composition sheet is determined by the design thickness of the prepreg and the resin ratio, but the usual thickness is 10 μm to 300 μm. When the thickness is less than 10 μm, there is a problem that the mesh of the fiber becomes conspicuous unless the reinforcing fiber is disentangled smoothly, and when it exceeds 300 μm, it is difficult to uniformly impregnate the reinforcing fiber. It is preferably 15 μm to 150 μm, more preferably 20 μm to 100 μm.

The reinforcing fibers used in the present invention are fibers for reinforcing plastics such as carbon fibers, aramid fibers, and cellulose fibers, and are not particularly limited. In addition, the form of the fibers includes UD sheets, knitted fabrics, tows, chopped fibers, nonwoven fabrics, and paper made by arranging fibers, and is not particularly limited. However, from the viewpoint of impregnation properties, the thickness of each fiber bundle is 1 mm or less, preferably 0.5 mm or less, 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, preferably 5:5 to 7:3 by volume ratio. When the ratio of the reinforcing fibers is less than 2, the amount of reinforcing fibers decreases, so there is a possibility that the strength required for the fiber-reinforced material cannot be sufficiently satisfied. When it exceeds 7, the resin may be insufficient and voids may increase.

If voids remain at the time of impregnation, it becomes a defect in the final product, and there is a possibility that desired strength may not be exhibited. Therefore, it is preferable to reduce voids at the time of impregnation. As the method, heat treatment and pressure treatment can be performed.

The heat treatment is usually performed at 50°C to 100°C. When the temperature is lower than 50°C, the viscosity of the resin cannot be sufficiently lowered, and poor impregnation may occur. In the case of exceeding 100°C, polymerization reaction may occur. The heat treatment time is usually 5 seconds to 3 minutes. If it is less than 5 seconds, depending on the thickness, the viscosity reduction and impregnation may not be sufficiently performed. If it exceeds 3 minutes, the polymerization reaction may slightly advance, and there is a possibility that desired viscosity may not be obtained.

As a method of further improving the impregnation precision, thermocompression bonding using a hot press, a hot roll, or the like can be mentioned. The pressure also depends on the substrate, but is 0.01 MPa to 1 MPa. If the pressure is less than 0.01 MPa, the impregnation may become insufficient, and if it exceeds 1 MPa, the reinforcing fibers may be damaged and the resin may flow out.

In the case of using the in-situ polymerizable thermoplastic epoxy resin of the present invention, an in-situ polymerizable thermoplastic fiber-reinforced plastic can be obtained by, for example, polymerizing at a temperature of 150 to 200° C. and a pressure of 0.1 MPa to 1.0 MPa.

The in-situ polymerizable thermoplastic epoxy resin of the present invention preferably has a weight average molecular weight (Mw) of 35,000 to 150,000, more preferably 50,000 to 100,000 in the in situ polymerized thermoplastic fiber reinforced plastic. The dispersion (polymerization average molecular weight/number average molecular weight) is preferably 1-20, more preferably 2-15. When the dispersion exceeds 20, it tends to be easily gelled. It should be noted that the dispersion will not be less than 1. In addition, glass transition temperature (Tg) shows the physical property of 100-130 degreeC.

Example

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples at all. Unless otherwise specified, "part" means part 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 & Materials Co., Ltd., molecular weight 228, melting point 158°C)

A2: 4,4'-(3,3,5-trimethylcyclohexyl)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 liquid epoxy resin (manufactured by Nippon Steel Chemical & Materials Co., Ltd., YD-128, epoxy equivalent 188g/eq)

B2: Tetramethylbisphenol F-type epoxy resin (YSLV-80XY: manufactured by Nippon Steel Chemical & Materials Co., Ltd., YSLV-80XY, epoxy equivalent 192g/eq)

B3: Tetramethylbiphenol type epoxy resin (manufactured by Mitsubishi Chemical Corporation, YX4000, epoxy equivalent 188g/eq)

[polymerization catalyst]

C1: Tris(p-methoxyphenyl)phosphine (manufactured by Hokko Chemical Industry Co., Ltd., TPAP)

[reinforcing 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 put into a separable flask equipped with a stirrer, a thermocouple, a nitrogen gas injection port, and a nitrogen gas discharge port, and the temperature was raised while stirring so that the powder did not fly without using a solvent. Since A1 starts to melt from the vicinity where the internal temperature exceeds 150° C., and A2 melts and becomes uniform at 180° C., 317 parts of 40° C. B1 is added and mixed therein, while cooling 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 to be 0, and the viscosity at 60° C. was measured using a CV-1s manufactured by Toa Kogyo Co., Ltd. and was 2 Pa·s.

100 parts of the precursor mixture were measured, and 2 parts of a 50% C1 catalyst solution previously dissolved in cyclohexanone were added and mixed to obtain an epoxy resin composition. When the appearance of the obtained epoxy resin composition was evaluated, it was 0, and the viscosity at 60° C. was measured using MCR102 manufactured by Anton Paar Corporation, and it was 5 Pa·s.

Evaluation of the appearance was carried out visually. When the insoluble matter precipitated in the sample, it was evaluated as ×. When the sample was taken into a petri dish with a thickness of 2 mm, the haze value was evaluated as △ when it was 30% or more , and the case where the haze value was less than 30% was evaluated as 0.

Using a bar coater preheated at 80° C., the obtained epoxy resin composition was applied to a silicone-coated release paper in a thickness of 50 μm. This was protected with a cover film made of polyethylene to obtain an epoxy resin composition sheet.

The peelability of the obtained epoxy resin composition sheet was evaluated and the result was 0.

It should be noted that the evaluation of the releasability of the composition sheet is 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 cracks in the sheet itself under the state of 23° C.×50% RH. defects to evaluate. If there is no transfer of the resin or a defect of the sheet, the releasability is evaluated as 0, and if there is a transfer of the resin or a defect of the sheet, the releasability is evaluated as x.

Next, the cover film was peeled off from the obtained epoxy resin composition sheet, and the carbon fiber (I1) was attached to the peeled resin surface so that the linear density of 15 strands per 10 cm was used. The hot press applied pressure so that the surface pressure became 0.5 MPa, and it was taken out after 1 minute, and it air-cooled, and the epoxy resin prepreg with Rc=33% was obtained.

The peelability of the obtained prepreg was evaluated and the result was 0.

In addition, the evaluation of prepreg detachability was judged by the presence or absence of resin transfer to the release paper which peeled from the prepreg in the state of 23 degreeC*50%RH. If there is no transfer of the resin, the releasability is evaluated as 0, and if there is a transfer of the resin, the releasability is evaluated as x.

In addition, when the viscosity of the obtained prepreg was evaluated, it was 0.

It should be noted that the evaluation of tack was performed by whether the prepregs were lightly stacked on each other in the state of 23°C x 50%RH, whether they could be peeled without disturbing the fibers, and whether they did not come off after lightly pressing with a roller. Adhesion to judge. It should be noted that "lightly overlapping" means bonding only by the weight of the prepreg, and "lightly pressing with a roller" means bonding the prepreg using a 500 g roller. When lightly stacked and peeled off without disturbing the fibers, and when lightly pressed with a roller, the adhesiveness that does not come off is exhibited, and the tackiness is evaluated as 0, and when lightly stacked and bonded, it is super strong , or when there was no adhesion even when lightly pressed with a roller, the tackiness was evaluated as x.

The release paper of the prepreg was peeled off in the state of 23 degreeC x 50 %RH. The prepregs were laminated in four layers of 0/90/90/0, and the obtained laminate was polymerized under the conditions of a press pressure of 0.5 MPa and 160° C. for 1 hour to obtain a laminate.

In the obtained laminate, the weight average molecular weight (Mw) of the in-situ polymerization type 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 Corporation. The chromatographic column connects TSKguardcolumnHXL, TSKgel GMHXL, TSKgel GMHXL and TSKgel G2000HXL in series, and the chromatographic column oven is 40°C. The eluent is tetrahydrofuran, and the detector is RI detector. For flow rates, set the sample side to 1 mL/min and the reference side to 0.5 mL/min. About 0.1 g of the laminated plate was weighed, dissolved in 10 mL of tetrahydrofuran containing 5% cyclohexanone as an external standard substance, filtered through a 0.45 μm PTFE membrane filter, and used for analysis. The molecular weight was converted using a standard polystyrene calibration line, and the dissolution time was corrected using cyclohexanone.

In addition, the glass transition temperature (Tg) of thermoplastic fiber-reinforced plastics is 100°C. In addition, the measuring method of Tg is as follows.

Based on JIS K 7121, the measurement was performed with a differential scanning calorimeter (manufactured by Hitachi High-Tech Science Company, EXSTAR6000 DSC6200) at a temperature increase of 10°C/min. The tangent of the state is the middle temperature of the variation curve).

Example 2

100 parts of A1 and 100 parts of A2 were charged into the same apparatus as in Example 1, and the temperature was raised until the contents were melted while stirring so that the powder did not fly. Since A1 starts to melt from the vicinity where the internal temperature exceeds 150° C., and A2 melts and becomes uniform at 190° C., 295 parts of 40° C. B1 is added and mixed therein, while cooling 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 carried out to obtain an epoxy resin composition, an epoxy resin composition sheet, a prepreg, and a laminate. The measurement of the obtained laminated board was performed similarly to Example 1.

Example 3

50 parts of A1 and 150 parts of A2 were charged into the same apparatus as in Example 1, and the temperature was raised until the content melted while stirring so that the powder did not fly. Since A1 melted from the neighborhood where the internal temperature exceeded 150° C., and A2 melted and became uniform at 200° C., 272 parts of 40° C. B1 was added and mixed therein, while cooling 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 carried out to obtain an epoxy resin composition, an epoxy resin composition sheet, a prepreg, and a laminate. The measurement of the obtained laminated board was performed similarly to Example 1.

Example 4

100 parts of A1 and 100 parts of A2 were charged into the same apparatus as in Example 1, and the temperature was raised until the contents were melted while stirring so that the powder did not fly. Since A1 melts from the vicinity where the internal temperature exceeds 150° C., and A2 melts and becomes uniform at about 190° C., 301 parts of B2 at room temperature are added and mixed therein, while cooling the system. Stirring was further performed to confirm the melting of B2, and it 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 carried out to obtain an epoxy resin composition, an epoxy resin composition sheet, a prepreg, and a laminate. The measurement of the obtained laminated board was performed similarly to Example 1.

Example 5

100 parts of A1 and 100 parts of A2 were charged into the same apparatus as in Example 1, and the temperature was raised until the contents were melted while stirring so that the powder did not fly. Since A1 melts from the vicinity where the internal temperature exceeds 150° C., and A2 melts and becomes uniform at about 190° C., 294 parts of B3 at room temperature are added and mixed therein, while cooling the system. Stirring was further performed to confirm the melting of B3, and it 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 carried out to obtain an epoxy resin composition, an epoxy resin composition sheet, a prepreg, and a laminate. The measurement of the obtained laminated board was performed similarly to Example 1.

Example 6

150 parts of A1, 25 parts of A2, and 25 parts of A3 were charged into the same apparatus as in Example 1, and the temperature was raised until the content melted while stirring so that the powder did not fly. From the vicinity where the internal temperature exceeds 150°C, A1 melts, and A2 and A3 melt and become uniform at about 190°C, so 69 parts of B1 at room temperature and 228 parts of B3 are added and mixed therein, while cooling the system. Stirring was further performed to confirm the melting of B1 and B3, and it 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 carried out to obtain an epoxy resin composition, an epoxy resin composition sheet, a prepreg, and a laminate. The measurement of the obtained laminated board was performed similarly to Example 1.

Comparative example 1

200 parts of A1 was injected|thrown-in to the apparatus similar to Example 1, and it heated up, stirring to the extent that powder does not fly, until the content melt|dissolved. From the vicinity where the internal temperature exceeds 155° C., A1 melts and becomes uniform at about 160° C., so 340 parts of 40° C. B1 is added and mixed therein, and the inside of the system is cooled. Initially, a homogeneous liquid mixture was obtained, but precipitation occurred during cooling to 50° C., resulting in a cloudy precursor mixture.

Using the obtained precursor mixture, the same operation as in Example 1 was carried out to obtain an epoxy resin composition, an epoxy resin composition sheet, a prepreg, and a laminate. The measurement of the obtained laminated board was performed similarly to Example 1.

Comparative example 2

200 parts of A2 was put into the same apparatus as in Example 1, and the temperature was raised while stirring so that the powder did not fly, and the temperature was raised until the content was melted, but even if the internal temperature reached 200°C, it did not melt. While adding and mixing 250 parts of 40° C. B1 there, the inside of the system was cooled. Furthermore, a cloudy precursor mixture was obtained during cooling to 50° C. while stirring.

Using the obtained precursor mixture, the same operation as in Example 1 was carried out to obtain an epoxy resin composition, an epoxy resin composition sheet, a prepreg, and a laminate. The measurement of the obtained laminated board was performed similarly to Example 1.

[Table 1]

In Example 1, when the method of directly putting epoxy resin into the molten mixture of BPA (A1) and BisP-HTG (A2) and cooling the system directly, crystallization did not occur, and a uniform resin mixture. The same results were obtained also in Examples 2 and 3 in which the ratio of BPA and BisP-HTG was changed. As shown in Examples 4 and 5, it turns out that even if the kind of epoxy resin was changed, the same result was obtained.

In Comparative Example 1 using BPA as a simple substance, re-precipitation of crystals was observed during cooling, and cloudiness occurred. Although this is considered to be influenced by the slightly remaining seed crystals in the flask, such a phenomenon was not observed in Examples 1 to 6, so it can be seen that the quality of the molten state is stabilized by mixing and using phenolic compounds. It should be noted that for the precursor mixture, it is considered that the re-precipitation of BPA is affected by shearing, but the measurement of the viscosity was unstable at 60° C., so the result could not be measured.

In Comparative Example 2 using BisP-HTG as a single substance, it did not melt even when it was heated to 200° C., and it did not melt even when an epoxy resin was added. The laminated board and the resin board are insufficiently polymerized compared with other materials. The reason is considered to be that if a rigid phenolic compound with a high melting point is used alone, the phenolic compound will not melt even at the curing temperature, and this will adversely affect the polymerization reaction.

That is, by mixing and using phenolic compounds, the melting temperature can be effectively lowered, and a phenolic compound having a rigid molecular structure can be used as a thermoplastic epoxy resin composition.

In summary, even rigid phenolic compounds with high melting points can significantly reduce the use of organic solvents by melt-mixing with other phenolic compounds. hot sex. In addition, by using a plurality of phenolic compounds as a resin mixture, precipitation of crystals can be suppressed, and thus the degree of polymerization of the laminate can be increased. Furthermore, regarding the epoxy resin composition sheet and the prepreg, it has been shown that peelability and tack can be adjusted with good productivity when aging treatment or the like is performed.

Industrial availability

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

Claims (15)

1. A precursor mixture, characterized in that, is a precursor mixture for the in-situ polymerization type thermoplastic epoxy resin obtained by polyaddition of a difunctional epoxy resin and a difunctional phenolic compound, Contains two or more types of difunctional phenolic compounds as essential components, the sum of the difunctional phenolic compounds is 0.9 to 1.1 moles per mole of the difunctional epoxy resin, and the viscosity at 60° C. is 1 Pa·s to 50 Pa·s. 2. The precursor mixture according to claim 1, wherein, does not contain solvent, or in the case of containing solvent, relative to the total amount of 100 parts by weight of the difunctional epoxy resin and the difunctional phenol compound, the solvent is 10 parts by weight servings or less. 3. The precursor mixture according to claim 1, wherein the haze value in the thickness direction is less than 30% when the thickness is 2 mm. 4. The precursor mixture according to claim 1, wherein the two or more kinds of difunctional phenolic compounds are selected from bisphenolic compounds and biphenolic compounds. 5 . The precursor mixture according to claim 1 , wherein the ratio of the largest component among the two or more types of bifunctional phenol compounds is 90% by weight or less. 6 . The precursor mixture according to claim 1 , wherein at least one of the two or more types of difunctional phenolic compounds has a melting point of 160° C. or higher. 7. An epoxy resin composition obtained by blending a polymerization catalyst with the precursor mixture according to any one of claims 1 to 6 and making them compatible with each other. 8. The epoxy resin composition according to claim 7, wherein, with respect to the total amount of the difunctional epoxy resin and the difunctional phenolic compound, a polymerization catalyst is used in an amount of 0.05 to 5.0% by weight without using a solvent, or using A polymerization catalyst is blended in the precursor mixture with an amount of solvent that is 2 times or less relative to the polymerization catalyst. 9. The epoxy resin composition according to claim 7, wherein the haze value in the thickness direction is less than 30% when the thickness is 2 mm. 10 . The epoxy resin composition according to claim 7 , wherein the viscosity at 60° C. is 3 Pa·s to 150 Pa·s. 11 . 11. A thermoplastic epoxy resin obtained by polymerizing the epoxy resin composition according to any one of claims 7 to 10. 12. 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 to 300 μm. 13. A sheet-shaped in-situ polymerization thermoplastic epoxy resin obtained by polymerizing the epoxy resin composition sheet according to claim 12. 14. A prepreg obtained from the epoxy resin composition according to any one of claims 7 to 10 and/or the epoxy resin composition sheet according to claim 12, and reinforcing fibers. 15. An in-situ polymerized thermoplastic fiber-reinforced plastic, which is obtained by polymerizing the prepreg according to claim 14.