JP6943086B2 - Curable resin composition and cured product - Google Patents

Description

The present invention relates to a curable resin composition containing a conductive polymer and a cured product using the same.

As a polymer material exhibiting high conductivity, a polymer material in which a conductive polymer such as polyaniline, polypyrrole, and polythiophene is combined with a protonic acid dopant is attracting attention. However, the polymer material has poor molding processability, and improvement in that respect has been required.

Patent Document 1 discloses an attempt to improve molding processability without lowering the conductivity of the polymer material. This document discloses a thermosetting composition obtained by adding a vinyl monomer such as divinylbenzene as a monomer having a cationically reactive group to a combination of a conductive polymer and a protonic acid dopant. It has been shown that this composition gives a cured product exhibiting conductivity by the protonic acid dopant acting as a cationic polymerization initiator by heating and polymerizing the monomer. It is described that this imparts thermosetting property to the conductive polymer material and improves the mechanical strength of the obtained molded product.

According to this method, the conductive polymer material does show curability, and although the mechanical strength of the molded product can be improved, the degree of improvement is not sufficient, and the mechanical strength is not sufficient. Further improvement was required.

JP 2015-10202

In view of the above situation, the present invention provides a curable resin composition containing a conductive polymer, which provides a cured product exhibiting excellent mechanical strength while exhibiting conductivity, and a cured product obtained by curing the curable resin composition. The purpose is to do.

As a result of diligent studies by the present inventors, a composition obtained by blending a conductive polymer and a protonic acid dopant with a compound containing two or more vinyl groups and two or more phenyl ring structures each exhibits curability. We have found that the cured product achieves excellent mechanical strength while maintaining conductivity, and have completed the present invention.

That is, the present invention is a curable resin composition containing a conductive polymer (a), a protonic acid dopant (b), and a polymerizable compound (c) represented by the following general formula (1) or (2). Regarding.

(In each general formula, A represents an arylene group containing the same or different benzene ring structure, R represents an m-valent or n-valent organic group, and X represents an oxygen atom, a sulfur atom, NH, or NR'represents. R'represents a monovalent organic group. M represents an integer of 2 to 10 and n represents an integer of 1 to 5.)
The substituent R in each general formula preferably represents an m-valent or n-valent organic group containing a benzene ring structure. Further, the substituent R in each general formula preferably represents an m-valent or n-valent organic group having an allyl group.

The polymerizable compound (c) is a polymerizable compound represented by the general formula (1), and X in the formula preferably represents an oxygen atom. The conductive polymer (a) is preferably a polyaniline or a polyaniline derivative. The protonic acid dopant (b) is preferably an organic sulfonic acid. The weight ratio of the total of the conductive polymer (a) and the protonic acid dopant (b) to the polymerizable compound (c) is preferably 70:30 to 20:80.

The present invention also relates to a cured product obtained by curing the curable resin composition.

Furthermore, the present invention also relates to composite materials containing the cured product and fibers or fillers.

Furthermore, the present invention also relates to a method for producing a composite material, which comprises a step of impregnating a fiber with the curable resin composition and then curing the fiber.

According to the present invention, it is possible to provide a curable resin composition containing a conductive polymer, which gives a cured product exhibiting excellent mechanical strength while exhibiting conductivity, and a cured product using the same. ..

The present invention will be described in detail below.

The curable resin composition according to the present invention contains a conductive polymer (a), a protonic acid dopant (b), and a polymerizable compound (c) represented by the following general formula (1) or (2). do.

The conductive polymer (a) is not particularly limited, and examples thereof include polyaniline, polypyrrole, polyphenylene vinylene, polythiophene, and derivatives thereof. Of these, polyaniline or a derivative thereof is preferable because it is excellent in molding processability. When polyaniline is doped with a protonic acid dopant, the dopant forms a salt with the imino group in the polyaniline. As a result, polyaniline changes to a state showing conductivity. The derivative such as polyaniline refers to a conductive polymer in which a substituent such as an alkyl group, an ether group, or a sulfonic acid group is introduced into the skeleton of each polymer such as polyaniline. As such a derivative, various commercially available products can be used. For example, as a polyaniline derivative, polyaniline having a sulfonic acid group is commercially available, and as a polythiophene derivative, poly (3,4-ethylenedioxythiophene) is commercially available. As the conductive polymer (a), only one type may be used, or two or more types may be appropriately combined and used.

The protonic acid dopant (b) is not particularly limited, and an organic acid or an inorganic acid can be used. From the viewpoint of improving the processability of the conductive polymer, an organic acid is preferable, and among them, an organic acid having a portion having a large steric hindrance is more preferable. The organic acid is not particularly limited, and examples thereof include organic sulfonic acid and organic phosphoric acid. Examples of the organic sulfonic acid include dodecylbenzenesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, polystyrenesulfonic acid, alkylnaphthalenesulfonic acid, anthraquinonesulfonic acid, alkylsulfonic acid, dodecylsulfonic acid, cypress sulfonic acid, dioctylsulfosuccinic acid, and the like. Examples thereof include porphyrin tetrasulfonic acid and polyvinyl sulfonic acid. Examples of the organic phosphoric acid include propyl phosphoric acid, butyl phosphoric acid, hexyl phosphoric acid, polyethylene oxide dodecyl ether phosphoric acid, polyethylene oxide alkyl ether phosphoric acid and the like. Of these, organic sulfonic acid is preferable, and dodecylbenzene sulfonic acid is more preferable. As the protonic acid dopant (b), only one type may be used, or two or more types may be appropriately combined and used.

The compounding ratio of the conductive polymer (a) and the protonic acid dopant (b) is not particularly limited, and can be appropriately determined from the viewpoint of conductivity and curability. If the amount of the protonic acid dopant is too small, the polymerization reaction of the polymerizable compound (c) may not proceed sufficiently, or the conductivity may not be exhibited. Further, if the amount of the protonic acid dopant is too large, the polymerization reaction of the polymerizable compound (c) starts at room temperature, and the polymerization reaction may not be controlled. From this point of view, for example, when the conductive polymer is polyaniline or a polyaniline derivative, the blending ratio of the nitrogen atom of polyaniline to the protonic acid dopant is in the range of 10: 1 to 1: 2. preferable.

In the present invention, the protonic acid dopant acts as a cationic polymerization initiator for the polymerizable compound (c) in addition to changing the conductive polymer into a state exhibiting conductivity. That is, some acidic groups of the protonic acid dopant attack the vinyl group of the polymerizable compound (c) to cation-polymerize the polymerizable compound (c) to form a polymer thereof, thereby forming a resin composition. Achieve curing. At room temperature, since the protonic acid dopant forms a salt with the conductive polymer, the action of the polymerizable compound (c) on the vinyl group is suppressed and the polymerization reaction does not proceed. However, when heated to about 80 ° C. or higher, some acidic groups of the protonic acid dopant are desorbed from the conductive polymer and attack the vinyl groups of the polymerizable compound (c). This makes it possible to easily control the progress of the polymerization reaction by heat treatment at a relatively low temperature.

The polymerizable compound (c) is a compound having a vinyl group which is a cationically reactive group, and is a compound represented by the following general formula (1) or (2).

In each general formula, A represents an arylene group containing a benzene ring structure. Examples of the arylene group containing the benzene ring structure include a phenylene group and a divalent group obtained by removing two hydrogen atoms from naphthalene, anthracene, biphenyl and the like. It is preferably a phenylene group. As shown in the above formula, the vinyl group is bonded to the arylene group represented by A, and specifically, is directly bonded to the benzene ring structure in the arylene group. A plurality of A's are included in each formula, and the plurality of A's may be the same as or different from each other.

R represents an m-valent organic group in the formula (1) and represents an n-valent organic group in the formula (2). Examples of such an organic group include a hydrocarbon group, a hydrocarbon group having an ether bond, an ester bond, or the like inside. Specifically, an m-valent group obtained by removing m hydrogen atoms from aromatic compounds such as benzene, biphenyl and naphthalene; m obtained by removing m hydrogen atoms from an organic compound having a cyclic structure such as dicyclopentadiene. Valuable groups; divalent groups obtained by removing two hydroxyl groups from bisphenols; phenol novolac, m-valent groups obtained by removing m hydroxyl groups from cresol novolac, and the like. Here, the bisphenols are not particularly limited as long as they are compounds having two hydroxyphenyl groups, and examples thereof include bisphenol A, bisphenol F, bisphenol C, and bisphenol S. As the organic group representing R, an organic group containing a benzene ring structure is preferable. Thereby, the mechanical strength of the obtained cured product can be further increased.

Further, the organic group representing R may be an organic group having one or more allyl groups, and this can be preferably used. Examples of such a group include an m-valent organic group obtained by introducing one or more allyl groups into the organic group exemplified above. Since the organic group having an allyl group can lower the melting point of the polymerizable compound (c), it can be easily mixed with other components at room temperature or a temperature close to it. Further, the curable resin composition of the present invention can be easily handled at room temperature or a temperature close to that of the present invention. For example, when the curable resin composition of the present invention is impregnated into a fiber, the impregnation is smoothly performed. Can be done.

In particular, as the organic group representing R, an organic group containing both a benzene ring structure and an allyl group is preferable. Specific examples of such an organic group include, but are not limited to, a divalent group obtained by removing two hydroxyl groups from diallyl bisphenol A.

X represents an oxygen atom, a sulfur atom, NH, or NR'. R'represents a monovalent organic group. R'is not particularly limited as long as it is a substituent capable of bonding to a nitrogen atom, and for example, an alkyl group such as a methyl group, an ethyl group or a propyl group, an aryl group such as a phenyl group or a methylphenyl group, a benzyl group or the like. An aralkyl group and the like can be mentioned. Oxygen atom is preferable as X.

m represents an integer of 2 to 10 and n represents an integer of 1 to 5. Therefore, the compound represented by the general formula (1) or (2) is a compound having 2 to 10 vinyl groups. Due to these vinyl groups, the polymerizable compound (c) exhibits cationically polymerizable properties.

Since the polymerizable compound (c) has two or more cation-polymerizable vinyl groups, the number of bonding sites due to polymerization increases, the polymer can be further polymerized, and a crosslinked structure can be formed. , The strength of the cured product obtained after the polymerizable compound (c) is polymerized can be increased. Further, since the polymerizable compound (c) has at least two benzene ring structures, the polymer of the polymerizable compound (c) becomes more rigid. As a result, the strength of the cured product obtained after the polymerizable compound (c) is polymerized can be further increased.

In the present invention, the blending amount of the polymerizable compound (c) can be appropriately determined in consideration of the conductivity and strength of the obtained cured product. However, if the amount of the polymerizable compound (c) is too small, the curability tends to decrease and the strength of the cured product tends to decrease, and conversely, if the amount of the polymerizable compound (c) is too large, the conductivity of the cured product tends to decrease. In consideration of these points, the blending amount of the polymerizable compound (c) is such that the total weight ratio of the conductive polymer (a) and the protonic acid dopant (b) and the polymerizable compound (c) is 70:30. The amount is preferably in the range of ~ 20:80, more preferably 60:40 to 40:60.

In the present invention, since the protonic acid dopant acts as a cationic polymerization initiator that initiates a cationic polymerization reaction by heating, the protonic acid dopant serves as a cationic polymerization initiator in addition to the function as a dopant component of the conductive polymer. It also has a function. Therefore, it is not necessary to add a cationic polymerization initiator other than the protonic acid dopant to the curable resin composition of the present invention. By not blending other cationic polymerization initiators, it becomes easy to control the polymerization reaction.

The curable resin composition according to the present invention contains components other than the conductive polymer (a), the protonic acid dopant (b), and the polymerizable compound (c) as long as the effects of the present invention are exhibited. It may be something to do. Examples of such components include compatibilizers, dispersants, defoamers, plasticizers, reactive diluents and the like. Further, a thermosetting resin other than the conductive polymer (a) or a thermoplastic resin may be contained.

The method for producing the curable resin composition according to the present invention is not particularly limited, but for example, the conductive polymer (a) and the protonic acid dopant (b) are mixed by a conventional method and then polymerized. It can be produced by adding the compound (c) and further mixing it.

The curable resin composition in which each component is mixed can be cured by polymerizing the polymerizable compound (c) by heating to give a cured product. The temperature at the time of heating is not particularly limited, but is, for example, about 80 to 140 ° C., preferably 90 to 120 ° C. Further, the heating time required for curing is not particularly limited and may be appropriately determined, but is, for example, about 30 minutes to 4 hours. In heating, a molded product having a predetermined shape can be obtained by molding the resin composition into a predetermined shape and pressurizing while heating.

Further, the curable resin composition of the present invention can be used as a resin matrix component constituting a composite material such as a fiber reinforced plastic. Specifically, as the composite material of the present invention, a filler or a fiber is dispersed in the curable resin composition of the present invention, or the fiber is impregnated with the curable resin composition of the present invention, and then the resin composition is used. Examples thereof include composite materials obtained by curing. The filler is not particularly limited, and either an organic filler or an inorganic filler can be used. The fiber is not particularly limited, and examples thereof include ceramic fibers such as carbon fiber, glass fiber, alumina fiber, and boron fiber; and organic synthetic fiber formed from aromatic polyamide, ultra-high molecular weight polyethylene, and the like. Only one type of filler or fiber may be used, or two or more types may be used in combination. Among them, since the curable resin composition of the present invention can be preferably impregnated into fibers, so-called semipregs and prepregs composited with an aggregate of fibers and fiber reinforced plastics (FRP) are preferable.

The method for producing the composite material of the present invention is not particularly limited, and for example, a method of mechanically stirring and mixing the curable resin composition and the filler of the present invention and then thermoforming, or the above-mentioned resin composition and fiber. A method of producing a semi-preg or a prepreg by synthesizing the aggregates of And so on. Further, using the curable resin composition of the present invention and an aggregate of fibers, FRP can be directly produced by a hand-reup method, a spray-up method, an injection RTM method, a filament winding (FW) method or the like.

Since the composite material of the present invention contains a curable resin composition as a resin matrix component, it has excellent mechanical strength while having conductivity. Further, since the resin composition of the present invention exhibits thermosetting property, there is an advantage that a conductive composite material can be produced by a conventional thermoforming method.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

(Synthesis Example 1)
The raw material diallyl bisphenol A (DA-BPA) and dimethyl sulfoxide (DMSO) as a solvent were added to the separable flask, and the mixture was stirred at room temperature for 5 minutes. Next, a 60% potassium hydroxide aqueous solution prepared in advance using 2.0 equivalents of potassium hydroxide was added to the system being stirred. Then, the flask was immersed in an oil bath at 70 ° C., and stirring was performed until the temperature in the system became stable. Subsequently, 2.02 equivalents of vinyl benzyl chloride (VBC) was added dropwise to the stirring system using a dropping funnel. As it was, it was stirred for 2 hours from the end of dropping to react. Then, distilled water was added to the system to stop the reaction and stop stirring. Subsequently, the sample was transferred to a liquid separation funnel, an extraction operation was performed using toluene, and then a washing operation was performed using a 5% potassium hydroxide aqueous solution and distilled water. Then, the sample was transferred to an eggplant flask and concentrated using an evaporator to remove the solvent, and the target yellow liquid diallyl bisphenol A type styrene derivative (DA-BPAS) was obtained in a yield of 90%.

(Comparative Example 1)
5.1 g of dodecylbenzene sulfonic acid was added to 2.2 g of polyaniline (manufactured by Regulus Co., Ltd.) in an emeraldine-based (EB) state, and the mixture was stirred at room temperature for 30 seconds using a rotation revolution mixer (ARE-310; manufactured by Shinky Co., Ltd.). After that, it was subjected to a roll mill treatment to obtain a paste-like mixture. 7.3 g of divinylbenzene was added to this paste-like mixture, and the mixture was stirred at room temperature for 20 minutes using a rotating revolution mixer. As a result, polyaniline A-dodecylbenzenesulfonic acid complex was well dispersed in divinylbenzene. The composition was obtained.

This polyaniline composition was placed in a mold and heated and compressed at 120 ° C. for 2 hours at 2 MPa using a hot press to cure the polyaniline composition. The obtained cured product was subjected to a bending test using an Instron universal testing machine. The maximum point strength and elastic modulus were measured for the three samples, and the average value thereof was obtained. As a result, the average value of the maximum point strength was 9.3 MPa and the average value of the elastic modulus was 485 MPa.

Further, after freezing the obtained cured product for one day, the conductivity was measured using Loresta GP MCP-600 (manufactured by Mitsubishi Chemical Analytech) according to a conventional method, and the conductivity was about 1.0 S / cm. rice field.

(Example 1)
5.1 g of dodecylbenzene sulfonic acid was added to 2.2 g of polyaniline (manufactured by Regulus Co., Ltd.) in an emeraldine-based (EB) state, and the mixture was stirred at room temperature for 30 seconds using a rotation revolution mixer (ARE-310; manufactured by Shinky Co., Ltd.). After that, it was subjected to a roll mill treatment to obtain a paste-like mixture. 7.3 g of diallyl bisphenol A type styrene derivative (DA-BPAS) is added to this paste-like mixture, and the mixture is stirred at room temperature for 20 minutes using a rotation / revolution mixer to prepare the diallyl bisphenol A type styrene derivative (DA-BPAS). A paste-like polyaniline composition in which the polyaniline A-dodecylbenzene sulfonic acid complex was well dispersed was obtained.

This polyaniline composition was placed in a mold and heated and compressed at 120 ° C. for 2 hours at 2 MPa using a hot press to cure the polyaniline composition. When the bending test was performed in the same manner as in Comparative Example 1, the average value of the maximum point strength was 17.1 MPa and the average value of the elastic modulus was 664 MPa, and it was found that the bending strength was superior to that of Comparative Example 1.

Further, after freezing the obtained cured product for one day, the conductivity was measured using Loresta GP MCP-600 (manufactured by Mitsubishi Chemical Analytech) according to a conventional method, and the conductivity was about 1.0 S / cm. , It was about the same as the conductivity in Comparative Example 1.

Claims (10)

A curable resin composition containing a conductive polymer (a), a protonic acid dopant (b), and a polymerizable compound (c) represented by the following general formula (1) or (2).

(In each general formula, A represents an arylene group containing the same or different benzene ring structure, R represents an m-valent or n-valent organic group, and X represents an oxygen atom, a sulfur atom, NH, or NR'represents. R'represents a monovalent organic group. M represents an integer of 2 to 10 and n represents an integer of 1 to 5.) The curable resin composition according to claim 1, wherein the substituent R in each general formula represents an m-valent or n-valent organic group containing a benzene ring structure. The curable resin composition according to claim 1 or 2, wherein the substituent R in each general formula represents an m-valent or n-valent organic group having an allyl group. The curable compound (c) according to any one of claims 1 to 3, wherein the polymerizable compound (c) is a polymerizable compound represented by the general formula (1), and X in the formula represents an oxygen atom. Resin composition. The curable resin composition according to any one of claims 1 to 4, wherein the conductive polymer (a) is a polyaniline or a polyaniline derivative. The curable resin composition according to any one of claims 1 to 5, wherein the protonic acid dopant (b) is an organic sulfonic acid. The item according to any one of claims 1 to 6, wherein the weight ratio of the total of the conductive polymer (a) and the protonic acid dopant (b) to the polymerizable compound (c) is 70:30 to 20:80. Curable resin composition. A cured product obtained by curing the curable resin composition according to any one of claims 1 to 7. A composite material containing the cured product according to claim 8 and a fiber or a filler. A method for producing a composite material, which comprises impregnating a fiber with the curable resin composition according to any one of claims 1 to 7 and then curing the fiber.