JPS5922726B2 - Tanso Sen Igan Yuji Yushi Sabutsu - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a carbon fiber-containing resin composition that can provide a carbon fiber reinforced composite material having excellent physical properties.

Carbon fiber has the characteristics of being lightweight, high strength, and high modulus, so in recent years, as its price has declined, it has attracted attention as a reinforcing material for composite materials. Materials are now being produced industrially.

Conventionally, carbon fiber reinforced composite materials have been mainly manufactured from carbon fibers and bisphenol A diglycidyl ether type epoxy resin, but in this case, there is a problem that composite physical properties at the performance level required for practical use cannot necessarily be obtained. .

In particular, inter-laminar shear strength, which is one of the most important physical properties of carbon fiber reinforced composite materials, is
rShearStrength) (hereinafter abbreviated as ILSS), the conventional technology has not yet reached the performance level required for practical use, and there are many applications including carbon fiber reinforced composite materials where reliability is important. There is currently a strong desire for improvement in the field of application. As is well known, the performance of carbon fiber reinforced composite materials largely depends on the adhesion between the carbon fibers and the matrix, and in order to produce composite materials with excellent performance, it is first necessary to improve the interfacial adhesion between the two. is an essential requirement.

Possible means for improving this interfacial adhesion include a method of improving it from the carbon fiber side and a method of improving it from the matrix (resin) side. As a method for improving the interfacial adhesion between the carbon fiber side and the resin, a method has conventionally been used in which the carbon fiber surface is oxidized in the gas phase or liquid phase. However, the surface oxidation treatment of carbon fibers must be carried out within the range of negligible weight loss and within the range of not impairing the strength of the fiber itself.
There is a natural limit to that extent. Furthermore, from the standpoint of effectively utilizing the functional groups introduced onto the surface of carbon fibers through oxidation treatment, there is a limit to the efficiency of their utilization unless there is some innovation on the part of the resin. Therefore, surface treatment of carbon fiber alone cannot improve the performance of carbon fiber reinforced composite materials.
It is difficult to improve beyond a certain level. Therefore, in order to produce carbon fiber-reinforced composite materials with excellent performance, it is necessary to improve the adhesion with the resin from the carbon fiber side, and at the same time, improve the adhesion with the carbon fiber from the resin side as well. It is thought that. In response to this situation, the present inventors have conducted intensive research with the aim of further actively improving the physical properties of surface-treated carbon fiber composites from the resin side. The present inventors have discovered a carbon fiber-containing resin composition having composite physical properties, and have completed the present invention.

That is, the present invention is directed to a vinyl addition polymer containing 2 mol % or more of one or more oxirane ring-containing monomer units as its constituent units, or 5 wt % of the vinyl addition polymer.
The present invention relates to a carbon fiber-containing resin composition comprising 30 to 70% by volume of a mixture of the vinyl addition polymer and another thermosetting resin or its precursor, and 70 to 30% by volume of carbon fibers.

The carbon fiber-containing resin composition of the present invention includes bisphenol A
Compared to conventional resin compositions mainly composed of diglycidyl ether type epoxy resin and carbon fiber, the composite exhibits extremely superior physical properties, and in particular, ILSS exhibits a higher value of about 1 to 3 Kf/i.

Further, the carbon fiber-containing resin composition of the present invention has the advantage that, within a certain composition range, the semi-curing step of stage B is substantially unnecessary when it is made into a prepreg. Furthermore, the carbon fiber-containing resin composition of the present invention has the advantage that it can be produced relatively inexpensively within a practically usable price range. In the carbon fiber-containing resin composition of the present invention, the vinyl addition polymer containing one or more types of oxirane ring-containing monomer units as its constituent components includes glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, α Monoethyl glycidyl acrylate, crotonyl glycidyl ether, glycidyl crotonate, glycidyl isocrotonate, monoalkyl itaconate monoglycidyl ester, diglycidyl itaconate, monoalkyl monoglycidyl fumarate ester, diglycidyl fumarate ester, monomaleic acid By polymerizing one or more oxirane ring-containing ethylenically unsaturated compounds selected from alkyl monoglycidyl esters, maleic acid diglycidyl esters, etc. alone or together with other ethylenically unsaturated compounds. refers to the vinyl-based addition polymer obtained by

These vinyl addition polymers contain one or more monomers selected from the aforementioned oxirane ring-containing ethylenically unsaturated compounds, or methyl methacrylate, ethyl methacrylate, butyl methacrylate, Alkyl methacrylates such as 2-ethylhexyl methacrylate and lauryl methacrylate, alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and lauryl acrylate, styrene, α-
Styrene derivatives such as methylstyrene and vinyltoluene, fatty acid vinyl esters such as vinyl acetate and vinyl propylate, unsaturated hydrocarbons such as butadiene and isoprene, halogenated unsaturated hydrocarbons such as vinyl chloride and chloroprene, acrylonitrile, and methacrylic. Unsaturated nitrile compounds such as nitrile, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinyl acetic acid, alpha-ethyl acrylic acid, angelic acid,
monomethyl, monoethyl, monobutyl esters of itaconic, maleic or fumaric acids;
unsaturated fatty acids such as maleic anhydride and itaconic anhydride;
2-hydroxyethyl methacrylate, 3-hydroxypropyl methacrylate, 2-chloro-3-hydroxypropyl methacrylate, phosphoric acid mono(hydroxypropyl methacrylate) ester, acrylamide, methacrylamide, N-methylolacrylamide, N-methoxymethyl By carrying out solution polymerization, emulsion polymerization, or suspension polymerization in a conventional manner with one or more monomers selected from ethylenically unsaturated compounds such as acrylamide and N-butoxymethyl acrylamide. manufactured by In this polymerization reaction, ketones, esters, alcohols, ethers, aromatic hydrocarbons, etc. can be used as reaction solvents depending on the type of monomer used. Further, as a dispersion medium when the polymerization reaction is carried out in a heterogeneous system, water or a mixture of water and a water-soluble organic solvent can be used. Further, as the polymerization initiator, peroxides, azo compounds, etc. can be used. Furthermore, a chain transfer agent such as a mercaptan can also be used if necessary. Among the vinyl addition polymers containing one or more oxirane ring-containing monomer units as a constituent component obtained in this way, the vinyl addition polymer containing 2 mol% or more of the monomer units is , is particularly effective in achieving the desired effects of the present invention.

On the other hand, the carbon fiber-containing resin composition of the present invention may contain only one or more of the above vinyl addition polymers as a matrix resin, or may contain one or more of the vinyl addition polymers. It is also possible to simultaneously contain an epoxy resin.

Considering the ease of handling during processing and the cost of the carbon fiber-containing resin composition of the present invention, it is practically preferable to use the vinyl addition polymer as a matrix resin rather than using the vinyl addition polymer alone. It is more effective to use a combination of coalescence and epoxy resin. In this case, the mixing ratio (weight) of the vinyl addition polymer and epoxy resin is 95:5 to 2:9.
The ratio is preferably within the range of 8, and most preferably within the range of 80:20 to 5:95. In the carbon fiber-containing resin composition of the present invention,
Epoxy resins that can be contained as desired include bisphenol A diglycidyl ether type epoxy resin, bisphenol F diglycidyl ether type epoxy resin, novolac type epoxy resin, glycerin glycidyl ether type epoxy resin, polyglycol diglycidyl Examples include ether type epoxy resins, cycloaliphatic epoxy resins, halogenated bisphenol A diglycidyl ether type epoxy resins, and the like. In addition to the vinyl addition polymer, the carbon fiber-containing resin composition of the present invention may optionally contain a mixture of an epoxy resin and other synthetic resins, or only other synthetic resins. You can also. Examples of other types of synthetic resins include unsaturated polyester resins, diallyl phthalate resins, polyimide resins, polyamideimide resins, and precursors (prepolymers) of these resins. On the other hand, carbon fibers contained as another essential component in the carbon fiber-containing resin composition of the present invention include carbon fibers, graphite fibers, graphite whiskers, and the like.

These fibers and whiskers are usually used in an amount of 2 to 40 parts by weight per 100 parts by weight of polyacrylonitrile fiber, rayon, pitch, aromatic hydrocarbon, carbon black resin.
Used in parts by weight.

The carbon fiber-containing resin composition of the present invention can be used in the form of a prepreg or not in the form of a C prepreg, and can be applied to commonly used press molding methods, filament winding molding methods, sheet winding molding methods, etc. It is molded using various methods and becomes the final form of various molded products.

Therefore, the carbon fiber-containing resin composition referred to in the present invention refers to a carbon fiber in an A-stage state in which carbon fibers are simply impregnated with a resin or a resin solution and are not subjected to any special treatment thereafter;
B-stage semi-cured prepregs (prepregs) that have been semi-cured by heat treatment after resin impregnation, and C-stage prepregs that have completely cured the resin by heat-curing the A or B stage. Contains. Examples of the present invention will be described below.

Example 1 Ethyl acetate 3009 was placed as a reaction solvent in a four-bottle flask with an internal volume of 1e equipped with a stirrer, a reflux condenser, a dropping load, and a thermometer, and the mixture was heated to 80°C while purging with nitrogen.
heated to.

Separately, methyl methacrylate 7 is added to the drip load.
09, butyl acrylate 509, glycidyl methacrylate 80f! , and 0.89% of N,N2-azobisisobutyronitrile as a polymerization catalyst was added dropwise into the flask over 2.5 hours.
The polymerization reaction was then completed by maintaining the internal temperature of the flask at 80° C. for 6.5 hours. The polymerization rate of the obtained copolymer was 95%. Next, 304 g of epoxy resin [Epicoat 8828] manufactured by SheIl, 199 g of boron trifluoride monoethylamine, and 1429 ethyl acetate were mixed and dissolved in 200 g of the polymer solution obtained here (resin content = 76 f1). Then, a matrix resin solution was prepared. Next, carbon fiber (high strength yarn, tensile strength 300Kf/Ml) obtained by finally firing the polyacrylonitrile fiber to 1300°C
l#. Tow (diameter approx. 8μ) with bow tension modulus 23t/M7l)
The carbon fiber tow, which had been oxidized with a sulfuric acid aqueous solution of potassium dichromate, was continuously impregnated with the matrix resin solution using a drum winder.

Then, the carbon fiber tow impregnated with resin is wound around a drum wrapped with silicone-treated release paper, aligned parallel to each other, and then the solvent contained in the resin is evaporated. , prepared prepreg. The prepreg obtained in this way has a length of 280 mm and a width of 30 mm. After cutting nine sheets into a size of minutes,
The mixture was further heated at 170°C for 1 hour. The obtained molded article was then placed in an oven and post-cured at 170° C. for 2 hours. The resulting composite contains 57% carbon fiber by volume and its ILSS8ASTM
As a result of measurement according to the method of D-2344, )9.10
K1 ``It was d.

Example 2 Instead of the matrix resin solution in Example 1, Shel
Epoxy resin “Epicote 8828” 228y1 manufactured by Company L
Boron trifluoride monoethylamine 19f11 and ethyl acetate 189 were added to: [kaji FZ;'m'. :Zmonshinsho=, a composite was prepared and its physical properties were measured.

The resulting composite contained 55% by volume carbon fiber and had an ILSS of 9.22 Kf/Rd.

Example 3 Instead of the matrix resin solution in Example 1, 600 f of a methyl methacrylate/butyl acrylate/glycidyl methacrylate ternary copolymer solution having the same copolymerization composition as in Example 1 was used! (Resin content = 2289), She
Epoxy resin “Epilord 8828” manufactured by II Company 152
f! , and boron trifluoride monoethylamine 19f!
A composite was prepared in the same manner as in Example 1 except that a matrix resin solution prepared by mixing and dissolving was used, and its physical properties were measured.

The resulting composite contained 53% by volume of carbon fiber and its ILSS was 8.60 KP/l-.

Example 4 Methyl methacrylate 709 and butyl acrylate 50f in Example 1! , and methyl methacrylate 120 instead of glycidyl methacrylate 80'
EXAMPLE 1 A methyl methacrylate/butyl acrylate/glycidyl methacrylate terpolymer was synthesized in the same manner as in Example 1 except that 9, butyl acrylate 609, and glycidyl methacrylate 209 were used.

The polymerization rate of the obtained copolymer was 95%. Next, 400y of the polymer solution obtained here (resin content = 1529
), epoxy resin manufactured by Shell [Epicoat 982
8” 2289, boron trifluoride monoethylamine 19f
! A composite was prepared in the same manner as in Example 1, except that a matrix resin solution prepared by mixing and dissolving , and ethyl acetate 189 was used, and its physical properties were measured. The resulting composite had a volume of 57%
of carbon fiber, and its ILSS is 8.56K.
It was f/Md.

Example 5 Methyl methacrylate 709, butyl acrylate 509, and glycidyl methacrylate 80f in Example 1! Instead of styrene 709, butyl acrylate 509, and glycidyl methacrylate 80
A styrene/butyl acrylate/glycidyl methacrylate terpolymer was synthesized in the same manner as in Example 1 except that Example 9 was used.

The polymerization rate of the obtained copolymer was 93%. Next, the polymer solution 4099 (resin content = 1529
), epoxy resin manufactured by Shell [Epicote 882
8” 2289, boron trifluoride monoethylamine 19f
! A composite was prepared in the same manner as in Example 1 except that a matrix resin solution prepared by mixing and dissolving 99% and ethyl acetate was used, and its physical properties were measured.

The resulting composite contains 55% by volume carbon fiber and its ILSS is 8.68K'/M77! It was hot.

Comparative Example 1 Instead of the matrix resin solution in Example 1, Sh
Ell Co., Ltd. epoxy resin "Epicote 88281450"
A composite was prepared in the same manner as in Example 1 except that a matrix resin solution prepared by dissolving 22.5 g of boron trifluoride monoethylamine and 222.5 g of ethyl acetate was used. Physical properties were measured.

The resulting composite contained 58% carbon fiber by volume and had an ILSS of 7.06 K'/Md.

Comparative Example 2 Methyl methacrylate 709 and butyl acrylate 50f in Example 1! , and 120 g of methyl methacrylate instead of 80 g of glycidyl methacrylate
g and butyl acrylate 80f! A methyl methacrylate/butyl acrylate binary copolymer was synthesized in the same manner as in Example 1 except that .

The polymerization rate of the obtained polymer was 96%. Next, the polymer solution 396f obtained here! (Resin content = 1529
), epoxy resin manufactured by Shell [Epicote 882
8” 2289, boron trifluoride monoethylamine 199
A composite was prepared in the same manner as in Example 1, except that a matrix resin solution prepared by mixing and dissolving , and ethyl acetate 229 was used, and its physical properties were measured.

The resulting composite contained 56% carbon fiber by volume and had an ILSS of 7.01K×4i.

Claims (1)

[Claims] 1. A vinyl addition polymer containing 2 mol% or more of one or more oxirane ring-containing monomer units as its constituent units, or a vinyl addition polymer containing 5% by weight or more of the vinyl addition polymer. 30 to 70% by volume of a mixture of and other thermosetting resin or its precursor, and 70 to 30% of carbon fiber
A carbon fiber-containing resin composition consisting of % by volume.