JPS6114167B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite material whose main components are aromatic polyamide fibers and a thermosetting resin.

In recent years, FRP, a composite material that uses various reinforcing materials as a structural material, has become the darling of plastics. Recently, the production of composite materials that use lightweight aromatic polyamide fibers with extremely high strength and elasticity as reinforcing materials and various resins as matrices has received new attention.

By the way, in the production of such composite materials of various matrices, the biggest factor determining their performance is increasing the adhesion between the reinforcing material and the matrix, especially the interlaminar shear strength. However, aromatic polyamide fiber itself generally has a property of having low adhesion to a matrix, and therefore does not exhibit sufficient shear strength as a composite material.

The present invention has been completed as a result of various researches in order to eliminate such drawbacks, and the gist of the present invention is that the general formula (However, n is an integer of 3 to 5) A composite material made by thermosetting and bonding an aromatic polyamide fiber and a thermosetting resin using a lactam compound and an isocyanate compound or a polyurethane compound whose both terminal groups are isocyanate. be.

In the present invention, the aromatic polyamide fiber refers to one in which 15 mol% or more of the bonding units of the polymer constituting the fiber are amide bonds, such as polyp-
Phenylene terephthalamide, poly p-aminobenzamide, etc. are used.

In the present invention, as the thermosetting resin, epoxy resins, phenolic resins, unsaturated polyester resins, etc., which are generally known as thermosetting resins, are used.

In the present invention, the isocyanate compounds used for adhesion between fibers and resin include isocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, dimethyldiphenylmethane diisocyanate, polyisocyanate (polymethylene polyphenyl isocyanate), and tolylene diisocyanate dimer (uretidine dione). , isocyanate derivatives such as a reaction product of trimethylolpropane and tolylene diisocyanate.

What is a urethane compound with isocyanate at both ends?
A reaction product of polyisocyanate and a substance containing two or more active hydrogen groups such as hydroxyl group, carboxyl group, amino group, active methylene group, etc. in the molecule, for example, a compound usually called a polyol such as polyester or polyether. The molar ratio is adjusted so that both ends are isocyanate.

Here, polyester refers to acids such as oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, superric acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, and isophthalic acid, or their acid anhydrides. one or more types of
Ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol,
butylene glycol, trimethylolpropane,
It is obtained by esterification reaction with compounds such as trimethylolethane, hexanetriol, glycerin, and sorbitol.

Polyethers include ethylene oxide, propylene oxide, trimethylene oxide, butylene oxide, α-methyltrimethylene oxide, 3,3'-dimethyltrimethylene oxide, tetrahydrofuran, dioxane,
It is obtained by ring-opening polymerization or copolymerization of cyclic ethers such as dioxane.

In addition, polyester during polyurethane production,
The polyisocyanate to be reacted with the polyether may be the above-mentioned isocyanate compound.

Examples of lactam compounds include 2-pyrrolidone, ξ-caprolactam, and α-piperidone.

In the present invention, such compounds may be used in combination in the form of a simple blend of an isocyanate compound or a polyurethane compound with both terminal isocyanates and a lactam compound, but they may be used in advance at a temperature of 80 to 150°C for 30 minutes. It is better to use the adhesive in a form in which the unstable isocyanate groups are made inactive by reacting for ~5 hours, and the adhesive has excellent stability over time and adhesive properties during use.

Here, the mixing ratio of NCO equivalent to NH equivalent is 1:0.5 to 1:2, preferably 1:0.8 to 1:
A ratio of 1.5 is good, and especially when used as a reaction product, a ratio of 1:1 or more with a higher NH equivalent provides better liquid stability and can be said to be a preferable application ratio.

As a method for producing a composite material, for example, (1) aromatic polyamide fibers or knitted fabrics made of them, using a combination of the above compounds as an adhesive,
The cord is treated with an organic solvent solution of adhesive, usually
After drying at about 100 to 350°C for 30 seconds to 30 minutes, a method may be used in which the thermosetting resin is impregnated, or (2) after the adhesive is mixed with the thermosetting resin, the mixture is Although a method of impregnating aromatic polyamide fibers may be used, the former method (1) is preferred because it is superior in terms of adhesiveness.

The ratio of aromatic polyamide fibers and thermosetting resin (matrix component) in the present invention varies depending on the use and purpose of the structure to be molded, but usually the range is 10-90% by weight polyamide fiber, 90% thermosetting resin
~100% by weight.

In addition to the above composition, the adhesive described above is attached to the interface between the aromatic polyamide fiber and the thermosetting resin.

Further, the amount of adhesive attached to the fibers is preferably 0.5 to 5%, preferably 0.3 to 3%, based on the weight of the fibers.
Below 0.1% the adhesion is insufficient, while above 5% the adhesion no longer increases and only stiffens the fibers.

Depending on the use and purpose of the structure, some additives such as fillers, pigments, weather/heat stabilizers, etc. may be added to the matrix component.

After being impregnated with resin and bonded, if the resin is cured by heating and pressurizing in a conventional manner, a thermosetting resin reinforced with aromatic polyamide fibers can be obtained.

As the curing agent for the thermosetting resin, conventionally known ones may be used, such as boron trifluoride monoethylamine complex salt for epoxy resins, benzoyl peroxide, etc. for unsaturated polyester resins.

The composite structure manufactured by the method of the present invention can be applied to various uses and purposes. For example, sports equipment, leisure equipment, various appliances, parts, etc. that require high strength and elastic modulus, as well as aerospace equipment, automobiles, and other equipment that require lightness and excellent properties of strength, elasticity, and heat resistance. It is effective when used in equipment, etc.

The present invention will be explained in detail below with reference to Examples. In the examples, % represents weight % unless otherwise specified.

Example 1 Highly elastic type poly P-phenylene terephthalamide filament 1500d was mixed with L-1007 (isocyanate groups at both ends, prepolymer for polyurethane elastomer, manufactured by Takeda Pharmaceutical Co., Ltd.) and 2-pyrrolidone in an NCO equivalent/NH equivalent ratio of 1. /1.3 methyl ethyl ketone solution and heated at 250°C.
and dried for 1 minute. The adhesion amount was 1%. The treated fibers are made into a resin consisting of 100 parts of Polymer 3308 (unsaturated polyester resin, manufactured by Takeda Pharmaceutical Co., Ltd.) and 2 parts of Niper BO (benzoyl peroxide made into a paste with DOP, manufactured by NOF). Impregnated with liquid, laminated an appropriate number of sheets, and with the fibers aligned in one direction, molded and cured by heat press at 130℃ for 1 hour (press pressure 10Kg/cm ² ), then further heated to 130℃.
I spent an hour postqueueing.

The length of the resulting composite material (60% fiber content)
A test piece of 20 mm, width 6 mm, and thickness 3 mm was made, and the short beam three-point bending method (distance between spans 13
The interlaminar shear strength (ILSS) was measured at 5.7 Kg/min, crosshead speed 1 mm/min)
It was warm in ^mm2 . The ILSS of the composite material prepared without adhesive treatment was 3.0°C/mm ² .

Example 2 The fibers treated with a combination of L-1007 and 2-pyrrolidone in Example 1 were impregnated with a resin solution consisting of 100 parts of Epikote 828 (epoxy resin, manufactured by Ciel Chemical) and 5 parts of boron trifluoride monoethylamine complex salt. Then, an appropriate number of sheets were laminated, and with the fibers aligned in one direction, they were molded and cured using a hot press at 150°C for 1 hour (press pressure 10/cm ² ), and then post-cured at 17°C for 2 hours.

ILSS of the obtained composite material (60% fiber content)
When measured in the same manner as in Example 1, it was 7.4 Kg/mm ² . The ILSS of the composite material prepared without adhesive treatment was 4.8 Kg/mm ² .

Example 3 The aromatic polyamide fiber used in Example 1 was
-1007 and ξ-caprolactam were immersed in a methyl ethyl ketone solution containing an equivalent ratio of NCO equivalent/NH equivalent of 1/1.3, and dried at 250°C for 1 minute. The amount of adhesion was 1%. The thus treated fibers were prepared in the same manner as in Example 2 to form a composite material (fiber content: 60
%) and measured the ILSS, it was 6.8Kg/mm ²
It was hot.

Example 4 L-1007 and 2-pyrrolidone were reacted at 110°C for 2 hours in a mixed solvent of methyl ethyl ketone and toluene blended at an equivalent ratio of NCO equivalent/NH equivalent of 1/1.3, and the residual isocyanate was reacted with di-N-butylamine. The excess amount of amine was titrated with aqueous hydrochloric acid using bromophenol brew as an indicator to determine the amount of residual isocyanate, and it was found that no isocyanate remained.

The aromatic polyamide fiber used in Example 1 was immersed in the methyl ethyl ketone solution of the above reactant.
It was dried at 250°C for 1 minute. The amount of adhesion was 1%. A composite material (fiber content: 60%) consisting of the thus treated fibers and an unsaturated polyester resin was prepared in the same manner as in Example 1, and the ILSS was measured to be 5.9 Kg/mm ² . In addition, a composite material (fiber content 60%) made of epoxy resin was prepared in the same manner as in Example 2, and the ILSS was measured to be 7.6.
It was Kg/ ^mm2 .

Example 5 The aromatic polyamide fiber used in Example 1 was mixed with Takenate D-102 (a reaction product of trimethylolpropane and tolylene diisocyanate, manufactured by Takeda Pharmaceutical Co., Ltd.) and 2-pyrrolidone in a ratio of NCO equivalent/NH equivalent of 1/1.3. The sample was immersed in a methyl ethyl ketone solution mixed in an equivalent ratio of 1, and dried at 250°C for 1 minute. The adhesion amount was 1%. A composite material (fiber content: 50%) consisting of the thus treated fibers and an epoxy resin was prepared in the same manner as in Example 2, and the ILSS was measured to be 6.5 Kg/mm ² . Takenate D-102
A composite material (fiber content: 60%) made of epoxy resin and epoxy resin was prepared in the same manner, and the ILSS was measured to be 6.0 Kg/mm ² .

As is clear from the above examples, the aromatic polyamide fiber-reinforced resin produced by the method of the present invention has excellent adhesion between fibers and resin, and fully reflects the excellent properties of aromatic polyamide fiber. In addition to its versatility, the industrial effects of the present invention are remarkable.

Claims (1)

[Claims] 1. General formula (However, n is an integer of 3 to 5.) The aromatic polyamide fiber and the thermosetting resin are bonded together by heat curing using a lactam compound represented by the formula (n) and an isocyanate compound or a polyurethane compound whose both terminal groups are isocyanate. A composite material whose main components are aromatic polyamide fiber and thermosetting resin. 2. The composite material according to claim 1, characterized in that the composite material is heat-cured and bonded using a reaction product obtained by reacting a lactam compound and an isocyanate compound or a polyurethane compound whose terminal groups are isocyanate in advance. 3. The composite material according to claim 1, wherein the composite material is heat-cured and bonded by a reaction product made by reacting the NCO equivalent to NH equivalent at a ratio of 1:1 or more.