JPS596441A - Leaf spring of fiberglass reinforced plastics for car - Google Patents

Abstract

PURPOSE:To obtain leaf spring of glassfiber reinforced plastics for car with excellency in fatigue resistance at high temp. by impregnating a fibrous reinforcement material with a resin compound of epoxy resin of bisphenol type and methylnazic acid anhydride, and by allowing them to harden in a form. CONSTITUTION:One or more sorts of fibrous reinforcement material selected from the groups of glassfiber, carbonic fiber and aromatic polyamid fiber is impregnated with a resin compound of methylnazic acid anhydride and bisphenol type epoxy resin with the mean epoxy equivalent ranging from 150 to 300, with or without accelerant according to need, and then they are allowed to harden in a form.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an FRP leaf spring for automobiles that has excellent fatigue resistance at high temperatures.

In recent years, as crude oil prices have soared, automobile manufacturers have begun to develop fuel-efficient vehicles in order to make more effective use of petroleum resources. The weight ratio of a car body is the most effective means of improving fuel efficiency, and for this reason, the use of plastic, which is a lightweight material, is being actively used in various parts of the car body.

In Japan, ethylene propylene diene terpolymer is used for corner protectors around bumpers, nylon and acetal resin are used for interior panels and various exhaust gas control devices, and polypropylene and acetal are used for full trimming. Resins are beginning to be used.

It is used for fenders, FRPU front grilles, bumpers, inner panels, skirt panels, fender 1 roofs, etc.

In addition, we have developed advanced bonding technology for the functional parts of automobiles such as leaf springs, drive shafts, and wheels.
Research is also actively being conducted to apply high-performance composite materials. 40-80% if these functional parts are replaced with advanced composites from conventional steel.
It can be expected to reduce the weight of objects, making it an effective means of improving fuel efficiency. In addition, this advanced composite has the advantage of being superior to conventional steel in terms of corrosion resistance.

By the way, in order to satisfy the special requirements for functional parts, such advanced composites are reinforced with glass fibers, carbon fibers, aromatic polyamide fibers, etc., used alone or in combination as reinforcing materials. Unsaturated polyester resins, epoxy resins, and epoxy vinyl ester resins are used as the matrices of stopper dams, and the performance is greatly influenced by these resin matrices. Steel laminated leaf springs are used in automobile leaf springs, especially light trucks and commercial vehicles, but if we were to make them into FRP, it would cost 1.2 to 1.4 cm per unit. It is possible to reduce the weight of the steel laminated leaf spring of 9 by about 60 to 80 times.

By the way, the characteristics required for automobile leaf springs are as follows:
Excellent fatigue resistance and heat resistance are required because of the need to withstand the harsh conditions of use. A hybrid system of carbon-based fibers or aromatic polyamide-based fibers alone or in combination should be used, while the matrix to which these reinforcements are bound can be unsaturated polyester resins, epoxy resins, or Epoxy vinyl ester resin should be used. However, although unsaturated polyester resin has great advantages in terms of molding speed and economy associated with mass production, the characteristics of this resin, namely a small elongation rate of 74% and a large curing shrinkage rate,
Furthermore, the poor adhesion to reinforcing materials is
When making leaf springs made of RP, the fatigue resistance is significantly reduced.On the other hand, epoxy vinyl ester resin
Although it has a molding speed comparable to that of unsaturated polyester resin, properties comparable to those of epoxy resin, and excellent adhesion to reinforcing materials, custom-made fatigue resistance, especially fatigue resistance at high temperatures, is still lacking. Inferior to epoxy resin. In contrast to these two resins, epoxy resin has properties such as heat resistance, high elongation, small curing shrinkage groups, and excellent adhesion to reinforcing materials, so it was used as a matrix for FRP leaf springs for automobiles. Finally, long-term fatigue resistance can be improved.

However, such FRP leaf springs for automobiles are required to have fatigue resistance properties at room temperature, but they also suffer from heat accumulation inside the FRP leaf springs due to repeated loads and heat from the exhaust pipes of surrounding cars. Fatigue resistance properties at high temperatures are required.

As a means to improve the heat resistance of epoxy resin, aromatic polyamine is added to bisphenol type epoxy resin.
Or thread that combines alicyclic polyamine, aromatic acid anhydride, alicyclic acid anhydride; phenol novolac type or cresol novolac type epoxy resin with aromatic polyamine, or alicyclic polyamine, aromatic acid anhydride. , an alicyclic acid anhydride; a system in which glinozylamine is combined with an aromatic polyamine, or an alicyclic polyamine, an aromatic acid anhydride, or an alicyclic acid anhydride; alicyclic epoxy Examples include a system in which a resin is combined with an aromatic acid anhydride or an alicyclic acid anhydride. However, most of the epoxy resins in this combination have a high viscosity and therefore have poor impregnating properties with fiber reinforcing agents, making it difficult to obtain FRP leaf springs of stable quality. Therefore, in order to reduce the viscosity, if the epoxy resin is kept at a high temperature and impregnated into a fibrous reinforcing material, the pot life will be extremely short, which will have the disadvantage of worsening workability when manufacturing FRP leaf springs. . Especially when using high-viscosity or solid epoxy resins such as high molecular weight bisphenol type, phenol novolac type, and cresol novolac type epoxy resins, glycidylamine, and aromatic polyamines and alicyclic polyamines as curing agents. When using a high melting point aromatic acid anhydride or a high melting point alicyclic acid anhydride,
It has a high viscosity, must be kept at high temperatures, has a short pot life, and has very poor workability, making it practically impossible. Further, a system in which an alicyclic epoxy is combined with an aromatic acid anhydride or an alicyclic acid anhydride has a low viscosity, a long pot life, and excellent heat resistance, but has poor fatigue resistance at high temperatures. Furthermore, systems that combine bisphenol-type epoxy resin and acid anhydride with phenol novolac-type epoxy resin, cresol novolak-type epoxy resin, or glycidylamine, which have excellent heat resistance, improve heat resistance, but , it is not possible to improve the fatigue resistance of FRP leaf springs at high temperatures.

The present inventors conducted intensive research focusing on epoxy resins that have excellent properties as a matrix in order to obtain such FRP leaf springs for automobiles.As a result, only in limited combinations of epoxy resins and curing agents, It has been found that it has excellent fatigue resistance at high temperatures.

That is, in the present invention, the average epoxy equivalent is about 150 to 3
A resin composition comprising a bisphenol type epoxy resin in the range of 0.00 and methylnadic anhydride, and optionally an accelerator, is mixed with at least one selected from the group consisting of glass fibers, carbon fibers and aromatic polyamide fibers. Automotive F with excellent fatigue resistance at high temperatures, made by impregnating one type of fibrous reinforcing material and hardening it.
The purpose is to provide a leaf spring made of RP.

The epoxy resin referred to in the present invention is a bisphenol type epoxy resin having an average epoxy equivalent of about 150 to 300, and an epoxy resin having an epoxy equivalent of about 150 to 300.
When using a bisphenol type epoxy resin alone within the range of
Epoxy resins in the range of 50 to 300 are also included.

Here, a representative example of the bisphenol type epoxy resin is a glycidyl ether type epoxy resin which substantially has two or more epoxy groups in one molecule and is obtained by the reaction of epichlorohydrin with bisphenol A or bisphenol F. Epoxy resins include dimethylglycidyl ether type epoxy resins obtained by the reaction of methylepichlorohydrin and bisphenol A or bisphenol F, or epoxy resins obtained from alkylene oxide adducts of bisphenol A and epichlorohydrin or methylepichlorohydrin.

Methylnadic anhydride used as a curing agent for these epoxy resins has a TE of 0.00% for epoxy #,lF''.
A suitable amount is 5 to 1.2 equivalents, preferably 0.7 to 1.0 equivalents. Furthermore, if it takes a long time to cure and mold the epoxy resin by simply blending the methylnadic anhydride with the epoxy resin, an accelerator may be used as necessary.

Such accelerators include diethylamine, triethylamine, diisopropylamine, monoethanolamine,
Jetanolamine, triethanolamine, methylethanolamine, methyljetanolamine, monoisopropanolamine, nonylamine, dimethylaminepropylamine, diethylaminepropylamine, benzyldimethylamine, α-methylbenzyldimethylamine, α-benzyljetanol Amine, 2,4.6-Dolis-dimethylaminomethylphenol (1) MP=30
), tri-2-ethylhexoate salt of DMP-30,
Pyridine, piperidine, N-aminepropylmorpholine, 1,8-diazabicyclo(5,4,0)undecene-
7 (DBU), L) Amines such as BU phenol, 2-ethylhexanoic acid, oleic acid, diphenylphosphorous acid, salts with organic phosphoric acids; 2-methyl-imidazole, 2-ethyl-4-methyl Imidazole 2-isopropylimidazole, 2-undecylimidazole,
Cyanoethylation type imidazole (abbreviated as 2-MZ-CN) obtained by reacting 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 2-methylimidazole with acrylonitrile. ), adduct of 2-MZ-CN and trimellitic acid, reaction product of 2-MZ-CN and dicyandiamide, imidazole and Cu, Ni, C.

Metal salt complexes such as imidazoles; BF, -monoethylamine, BF3-benzylamine, BF s-dimethylaniline, BF3-triethylamine, Bl'i
', -n-hexylamine, BF3-2,6-diethylamine, 13F, -aniline, BF3-amine complexes such as -piperidine, amine imide compounds using 1,1-dimethylhydrazine as starting materials; tin octylate, etc. Examples include organic acid metal salts.

Among the above-mentioned fibrous reinforcing materials, glass fibers include E-glass, C-glass, A-glass, and S-glass in terms of their raw materials, but in order to obtain the leaf spring of the present invention, Either type can be applied.

Next, the carbon fibers mentioned above include carbon fibers and graphite fibers, both of which are manufactured using polyacrylonitrile fibers, cellulose fibers, pitch, aromatic hydrocarbons, carbon black, etc. as raw materials. It is something.

In addition, the above-mentioned aromatic polyamide fiber is a polymer obtained by the reaction of a polyfunctional aromatic amine and an aromatic polybasic acid, and has an amide bond. Examples include polyP-phenylene terephthalamide, mataha, I-'IJP-aminobenzamide, and the like.

These fibrous reinforcing materials have various shapes depending on their shape, such as roving, chopped strand mat, continuous mat, cloth, low pink cloth, surfing mat, and chopped stride. In this case, roving, cloth, raw pink cloth, etc. are preferred because they can have a high fiber content and also improve the strength and fatigue resistance of the FRP molded product.

In obtaining the leaf spring of the present invention, the volume content of the fibrous reinforcing material is preferably in the range of 40 to 70 inches of the total capacity of the reinforcing material and the resin as a matrix component, and in terms of weight, it is 50 to 80 inches. The range is preferred, and the most practically preferred range is 45 to 65% of the total capacity.

In addition, in order to obtain the FRP leaf spring for automobiles of the present invention, in addition to the resin component, fibrous reinforcing material, and hardening agent, pigments, dyes, mold release agents,
Fillers or other additives may also be included.

The FRP leaf spring for automobiles of the present invention can be produced by the commonly used press molding method, filament winding molding method,
It is molded using methods such as sheet winding molding, pultrusion molding, or pull forming molding.

Next, the present invention will be specifically explained using examples.

Examples 1 to 4 [Epiclon 850J (manufactured by Dainippon Ink & Chemicals Co., Ltd.) with an epoxy equivalent of 190 obtained by the reaction of bisphenol A and epichlorohydrin, and [Epiclon 860J (product of the same company) with an epoxy equivalent of 260] or an epoxy equivalent of 4900 [Epicron 1050J (product of the same company), methylnadic anhydride and benzyldimethylamine,
The resin compositions were sufficiently mixed at the blending ratios shown in Table 1 (unit: duram) to obtain a resin composition.

Table 1 The storage stability of the above composition was evaluated by measuring the change in viscosity over time at each temperature using a B-type rotational viscometer. Pot life after formulation of these compositions
The viscosity of these compositions is 1000 cps at each temperature.
The time taken to reach the O value was taken as the time.

These blended compositions were poured into a mold made in advance from a glass plate, and heated at 100°C for 1 hour, and then at 140°C for 2 hours.
After curing for a while, a cast product with a thickness of 3 and 15 cm was created.

Specimens were cut from these castings according to the respective JIS standards and their mechanical properties were measured. Table 3 shows the pot life and mechanical properties of these compositions.

Ten sheets obtained by thoroughly impregnating glass rovings aligned in one direction with the above-mentioned blended composition were placed in a matte die mold (8 fins deep, 8 fins wide) so that the glass content was 70 inches. 50m x length 300mm), 1
Heat compression molding was performed at 20° C. for 1 hour. Obtained FR
The P molded body was further subjected to after-curing at 140° C. for 2 hours in an electric heat dryer.

Next, the thus obtained molded body (leaf spring basic body) was subjected to stress condition 3 using a spring-coated high-speed fatigue test material.
5±30 kgf;/mm2, measurement temperature 25℃ and 90
A fatigue test was carried out at ℃ to determine the number of repetition lifespans, and as shown in Table 3, the leaf spring of the present invention had an unprecedented repetition life at high temperatures. was confirmed. It should be noted that the number of repetitions in life is expressed as the number of times until the rigidity decreases by 10 inches.

Example 5 [Ebicuron 830J (product of the same company) 1ooor and methylnadic anhydride] with an epoxy equivalent of 177 obtained by the reaction of bisphenol F and epichlorohydrin] 0
10 f and benzyldimethylamine 10'? were thoroughly mixed to obtain a resin composition.

The pot life and mechanical properties of the cured product of the obtained resin composition were measured in the same manner as in Example 1.゛The results are shown in Table 3.

Next, an FRP molded article was prepared using this resin composition in the same manner as in Example 1, and a fatigue test was conducted under the same conditions as in Example 1, and the results shown in Table 3 were obtained.

Comparative Example] ~2 "Epiclon 850" with an epoxy equivalent of 190 and methyltetrahydrophthalic anhydride: "Epiclon B-570"
J (product of the same company) or methylhexahydrophthalic anhydride: [Epiclon B-650J (product of the same company) and benzyldimethylamine were thoroughly mixed in the proportions shown in Table 2 to obtain a resin composition. Ta.

The pot life and mechanical decay of the cured product of the obtained resin composition were measured in the same manner as in Example 1, and the results are shown in Table 3.

Next, an FRP molded article was prepared using this resin composition in the same manner as in Example 1, and a fatigue test was conducted under the same conditions as in Example 1. The results are shown in Table 3.

Table 2 Comparative Example 3 "Epicron 850J500 F" with epoxy equivalent of 190
, "Epiclon 430J" with an epoxy equivalent of 120 obtained from diaminodiphenylmethane and epichlorohydrin.
(Same company product) 500f.

"Epiclon B-570" 1130 r and benzyldimethylamine 101 were thoroughly mixed to obtain a resin composition.

The pot life and mechanical properties of the cured product of the obtained resin composition were measured in the same manner as in Example 1. The results are shown in Table 3.

Next, an FRP molded article was prepared using this resin composition in the same manner as in Example 1, and a fatigue test was conducted under the same conditions as in Example 1. The results are shown in Table 3.

Comparative Example 4 [Epicron 850J] 00(1',!:') was sufficiently mixed with Tuff Elene Diamine 1409 to obtain a resin composition.

Regarding the obtained resin composition, the pot life and mechanical properties of the cured product were evaluated in the same manner as in Example 1, and the results are shown in Table 3.

Next, an FRP molded article was prepared using this resin composition in the same manner as in Example 1, and a fatigue test was conducted under the same conditions as in Example 1. The results are shown in Table 3.

In addition, the above-mentioned measurement of mechanical properties and fatigue resistance properties was performed using the following testing machine.

〔mechanical nature〕

Testing machine: “Tensilon UT” manufactured by Toyo Baldwin Co., Ltd.
M-1-500o BJ "Heat deformation temperature measuring device" manufactured by Uejima Seisakusho "Barcol hardness meter" manufactured by BARBER-COLMAN [Fatigue resistance properties] Testing machine: Spring type high-speed fatigue tester Rotation speed: 11000 rp Setting 35 ±30 kg f/m 4-point bending method Dimensions of specimen: 50x300x8 As can be seen from each side, the resin composition of the specific epoxy resin and methylnadic anhydride according to the present invention was used.17 The FRP molded product obtained when used in Tuxus has a cyclic life at high temperatures about five times longer than that obtained when an epoxy resin outside the scope of the present invention is used.

Therefore, it can be seen that the FRP leaf spring for automobiles of the present invention has extremely excellent fatigue resistance at high temperatures.

Patent Applicant Toyota Motor Corporation Chuo Hatsu 6 Co., Ltd. Continued from page 1 Applicant Dainippon Ink & Chemicals Co., Ltd. 3-35-58 Sakashita, Itabashi-ku, Tokyo

Claims (1)

[Claims] 1. A resin composition comprising a bisphenol-type epoxy resin having an average epoxy equivalent of about 150 to 300, methylnadic anhydride, and optionally an accelerator, and a glass fiber, Fatigue resistant at high temperatures obtained by impregnating at least one type of fibrous reinforcing material selected from the group consisting of carbon fibers and aromatic polyamide fibers and hardening and molding! ＃FRP plate for automobiles with excellent surname. 2. The volume-containing group of the fibrous reinforcing material is 40 to 40% of the total volume of the reinforcing material and the resin composition as a matrix component.
The FRP leaf spring for an automobile according to claim 1, characterized in that the electric resistance welding is 70%s or 50 to 80cm in total.