JPH0645670B2 - Epoxy resin composition for FRP molding - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an epoxy resin composition, particularly an acid anhydride curing agent thread epoxy resin suitable for large-scale FRP molding requiring a long molding operation. It relates to a composition.

[Conventional technology]

In recent years, FRP products have been required to be large-sized and have high performance, and quality control of resins during molding has become important. In such large-sized, high-performance molded products, especially filament winding molding, acid anhydride curing agent type epoxy resin, which is excellent in low viscosity and long pot life, is used. A certain acid anhydride absorbs moisture to form a free carboxylic acid, and its viscosity increases. In addition, since the carboxylic acid has a slower curing speed than its acid anhydride, it causes curing failure and sometimes leads to deterioration of product quality.

Therefore, when an acid anhydride-based curing agent is used, it is important to control the humidity, but the larger the molded product or molding machine, the more difficult it becomes to control this humidity.

[Problems to be Solved by the Invention]

Therefore, the object of the present invention is to eliminate the need for a dehumidifying device, to have no influence on the physical properties such as strength even when used for a long time under high humidity, and to prevent the interlayer adhesive force from being extremely lowered.
It is to provide an epoxy resin composition for RP molding.

[Means for Solving the Problems]

That is, the present invention is an organic compound which has a liquefaction temperature of 30 to 150 ° C. and is rich in water repellency with respect to an acid anhydride which is an epoxy resin curing agent, and which is incompatible with the epoxy resin and the acid anhydride. It is an epoxy resin composition for FRP molding, wherein at least one kind of compound is added as a moistureproof agent in the range of 0.1 to 2% by weight.

Next, the contents of the present invention will be described in detail.

First, the epoxy resin used in the present invention includes bisphenol type, glycidyl ester type, glycidyl amine type,
It may be a novolac type, an aliphatic type, or a heterocyclic type. Taking the epicoat of oiled shell epoxy as an example,
For example, bisphenol type is 828 or 1001, glycidyl ester type is 872 or 191P, glycidyl amine type is 604, and novolac type is 152 or 1.
54 is YED-111 or YED-122 in the aliphatic type
However, RXE-15 and the like are known as heterocyclic compounds, and one kind or a mixture of two or more kinds thereof is used.

The acid anhydride type curing agent may be any of aromatic type, aliphatic type, halogen type aromatic and the like. Taking, for example, those manufactured by Shin Nippon Rika Co., Ltd., TMTA and TMEC are examples of aromatic compounds, and HH, HT, MH-700, PAZ-90 are examples of aliphatic compounds. When using such an acid anhydride-based curing agent,
You may use a tertiary amine etc. as a hardening accelerator.

Next, in the present invention, the addition amount of the moisture barrier which is the most important skeleton is based on the weight of the acid anhydride in the resin composition.
It is preferable to add 0.1 to 2% by weight, preferably 0.5 to 1% by weight. If the addition amount is less than 0.1% by weight, the moisture-proof effect is lowered, and if it is more than 2% by weight, the mechanical strength is lowered. Further, the type of the moisture-proofing agent used is required to have a high water repellency and be completely incompatible with the epoxy resin and the acid anhydride. Typical examples having such properties include, for example, hydroxypolyester, beeswax, carnauba wax, normal paraffins having 20 or more carbon atoms, ester compounds having 25 to 33 carbon atoms as the main component of an aliphatic rule, and carbon numbers. 12 to 31 aliphatic carboxylic acid esters and the like. Among the moisture-proofing agents, those having low water repellency and those having high solubility must be added in an increased amount in order to obtain a high moisture-proofing effect, resulting in a decrease in mechanical strength.

These moisture-proofing agents are used by being uniformly dispersed in an epoxy resin containing an acid anhydride type curing agent. At this time, in order to improve the dispersibility, it is preferable to stir with a stirrer at a rotation speed of preferably 1,500 times / min or more, preferably 10 minutes or more. In addition, you may heat if it does not harden | cure.

[Action]

Since the moisture-proofing agent uniformly dispersed in the epoxy resin composition does not dissolve in the resin, it causes phase separation over time, thereby forming a thin film on the surface of the resin. It is considered that the coating film formed in this way prevents water from entering.

〔Example〕

Hereinafter, the present invention will be specifically described based on Examples and Comparative Examples.

Examples 1 to 9 and Comparative Examples 1 to 3 As the epoxy resin, bisphenol A (trade name: Epicoat 828 manufactured by Yuka Shell Co., Ltd.), bisphenol F
(Dai Nippon Ink Co., Ltd. product name: Epicron 830), p
-Aminomethylphenol (trade name of Sumitomo Chemical Co., Ltd.,
ELM-100), methylhexahydrophthalic anhydride as acid anhydride curing agent (MeHHPA, Hitachi Chemical Co., Ltd.)
Product name: HN-5500), methyl tetrahydrophthalic anhalide (MeTHPA, Hitachi Chemical Co., Ltd. product name: HN-2200), secondary amine 2-ethyl-4-methylimidazole as a curing accelerator ( 2E4MI, Shikoku Kasei Co., Ltd.
Product name: 2E4MZ), 1: 1 of hydroxy polyester and normal paraffin having 20 or more carbon atoms as a moisture barrier
Mixture (S-740, manufactured by Big Chemie) and beeswax first
The epoxy resin compositions of Examples 1 to 9 and Comparative Examples 1 to 3 were prepared by mixing in the proportions shown in the table.

The weight increase of the obtained epoxy resin compositions of Examples and Comparative Examples after 16 hours in an incubator at a temperature of 39 ° C. and a relative humidity of 87% was measured. The results are shown in Table 1 as water absorption. In the example in which the moistureproof agent was added,
The amount of mass increase due to moisture absorption was as low as about 1/6 of that of the non-added comparative example, and neither the increase in viscosity due to hydrolysis nor the surface skinning observed in the non-added or comparative examples was observed.

Next, after curing the epoxy resin compositions of each of the Examples and Comparative Examples at 140 ° C. for 2 hours, the surface of the obtained cured product was sticky and the surface of the cured product was impregnated with acetone. The stickiness after wiping with absorbent cotton was examined. The results are shown in Table 1. The surface of the cured product was not sticky in each of the examples to which the moisture-proofing agent was added, but the surface of the cured product was sticky in each of the non-added comparative examples due to poor curing.

[Effects of the Invention] According to the present invention, it becomes possible to provide an epoxy resin composition for FRP molding in which the mechanical strength after curing does not change even when molding is performed for a long time under high humidity, and practical effects Is quite noticeable.

Claims (1)

[Claims] 1. An acid anhydride, which is an epoxy resin curing agent, has a liquefaction temperature of 30 to 150 ° C. and is highly water repellent.
In addition, at least one or more kinds of organic compounds that are incompatible with the epoxy resin and the acid anhydride are added as a moistureproofing agent in the range of 0.1 to 2% by weight.
Epoxy resin composition for RP molding.