JPS5991039A - Manufacture of foamed and molded item - Google Patents

Abstract

PURPOSE:To make cells uniform and fine, to make the diffusion of a gas in a molded item good, and to make the shock resistance good, by impregnating a thermoplastic resin with a halogenated hydrocarbon containing at least one fluorine followed as a foaming agent by injection molding. CONSTITUTION:The foaming agent should have a boiling point in the range of -90-50 deg.C under normal pressures, and examples of the foaming agents are CHClF2, CCl2F2, CClF2-CClF2, CCl3F, etc. First, pellets of a thermoplastic resin are charged into a high pressure tank, and then a foaming agent is charged into said tank at room temperature under 1-20kg/cm<2> thereby impregnating the resin therewith. In this case, if the amount of the impregnation is 0.5-10wt%, the gasifying rate at room temperature under normal pressures is low, therefore an enough amount of a gas is generated during the molding to attain the aimed foaming rate, and the gas in the molded item can be released within a short period of time, so that the degassing period can be shortened and the adverse effect of the gas in the case of painting can be obviated.

Description

DETAILED DESCRIPTION OF THE INVENTION Hyokomei is a structural form that has a Zandwich structure of mainly °C skin 1Δ and foaming 1ω that is eroded by injection molding.
This relates to the method for manufacturing Ij2 type products.

Conventionally, when performing foam injection molding of high corrosion point polymers such as polyamide, polyester, modified polyphenylene oxide, ABS, and polystyrene, chemical blowing agents such as azo, nitroso, and hydrazine threads have been used as JIJITL agents. Among them, azo dicarbonamide is the most commonly used. However, while these foaming 1゛d7 sums exhibit excellent foaming performance, the foaming agent residue is the problem.

This method has major drawbacks such as the fact that the mold gets clogged with ribs, holes, etc. and must be removed every few shots, and the mold gets rusted and corroded by the mold residue.

Furthermore, the molded products used by these tearful executors have a low rate of scum diffusion within the molding, and if painted immediately after molding, the gas inside the molded product will lift the film and cause countless small swellings. There is a basic drawback that causes it to occur, so 7 to 3 days 11
The problem with degassing the 1j was that it could not be completed unless the Suke+1FJ molded product was stocked. Moreover, since the decomposition products contain ammonia, the working environment is not favorable.

On the other hand, what about nitrogen gas, which is used as a physical blowing agent, with a screw? - A method has been adopted in which nitrogen gas is forced in and dispersed during the plasticization of the fat, but this method has a major drawback in that the nitrogen gas is not sufficiently dispersed and large voids are likely to occur inside the molded product. Further, even when painting a molded article obtained by this method, it is necessary to degas the IKJ for 3 to 3 days, as in the case of using a chemical foaming agent.

Historically, chemical foaming method and nitrogen gas physical foaming method have been used to
Due to the roughness (swirl) generated on the surface of the foamed molded product, it lacks impact resistance and also reduces the quality of the coating.

Thus, the present invention has focused on the above-mentioned problems, eliminates the drawbacks, eliminates the concern of mold rust and corrosion even when foam molding is performed using a high melting point polymer, and achieves the following foam molding in a timely manner. The purpose of this invention is to provide a method for producing a foam molded product that shortens the degassing time of the product and has -fn impact resistance. The thermoplastic resin is impregnated with a halogenated hydrocarbon containing fluorine or more under a predetermined pressure and then injection molded.
The solubility of the above-mentioned blowing agent in J resin is higher than that of conventional blowing agents, so a uniform foamed molded product can be obtained because it is impregnated with a thermoplastic resin in advance and then foam-molded, and also used in the present invention. The blowing agent has a high boiling point under linear pressure, so it is possible to suppress the gasification rate of the blowing agent at room temperature and increase the amount of gas generated by the blowing agent during injection molding. is the outside of the molded body during the fish time.
It has the property of being able to be released, thereby shortening Ill during degassing of 5D foam molded products and reducing gas damage during painting.

Here, the blowing agent used in the present invention is a halogen arsenic hydrocarbon containing at least 7 or more fluorine atoms, and has a boiling point of −0° C. when present. ℃ range, specifically Niha-CHCe Fx, CCetFm.

CCe F! -CCe F! , Aluii, tc ce
s F etc.

Such a cutting agent is impregnated with a thermoplastic resin, but first the thermoplastic resin pellets are placed in a high-pressure tank, and then a blowing agent is added. The foaming agent is impregnated (dissolved) into the thermoplastic resin pellet by putting it into a tantalum under condition F at a temperature of 0 c/d and g. The degree of impregnation of the foaming agent in this wound is O, S ~ 70
If the amount of impregnation is within this range, the amount of gas generated during molding becomes the weight, and a molded product with an expansion ratio of up to 7% can be obtained.

In addition, 1 f+L! Tables 1 and 2 show CHCeFg (Freon 2) for modified polyphenylene oxide, respectively.
2) and the results regarding the maximum dissolution +A of N2, it is shown that the @ foaming agent used in the present invention has a much higher solubility than nitrogen gas, and this results in Since the foaming agent used in the present invention has a 611 point value, the gasification rate is low at room temperature and under acoustic pressure. Gasification of the blowing agent is less likely to occur at room temperature, and sufficient gas can be generated during molding, making it possible to obtain a molded article with the desired expansion ratio.

Blank number below / Maximum storm of Freon 2.2 impregnated into surface resin (mold part %) number,
2 surface (maximum range of N2 impregnated into fat (wt%)) The thermoplastic resins used in the present invention include polyamide, polyester,
Modified polyphenylene oxide, ABS, polystyrene, etc. (200-300'QCI') are used, and molding γm 1 degree is also examined (1, 1, 1, 2, 3, etc.) resins (select according to the fat, filter, etc.) It is usually above 200'C and therefore thermoplastic;+! Original 71 impregnated in fat
The gasification rate of the agent is large, and the gas generation region rapidly increases, resulting in a molded product with an appropriate expansion ratio.

For injection molding, a normal injection molding machine is used, but various types of injection molding machines may be used, but a special molding machine for structural foam is mainly used.

Hereinafter, the present invention will be described in more detail with reference to Examples.

(Example 1) After adding a modified polyphenylene oxide with a ratio of fJ7 /, / to rank 1, Freon 22 (CHceF*
Molecule il! gB, boiling point -ti/"C) is added,
Modified polyphenylene oxide impregnated with type 2 Freon 22 was obtained, and this was processed using a low-pressure SF machine (EX7Co).
ee-0 company'S 'l OOton) is used for cylinder,
Both manifolds were molded using Ichitsu O'C. The obtained molded product had uniform fine cells, and the expansion ratio was 1.2 times. Even after 100 shots were molded, no rust was observed on the mold, and even after painting 2 hours after molding, no ba was observed on the coating film.

In addition, the falling ball impact resistance was measured, and this was measured in terms of diameter/inch and weight of 1. It is determined by the equation of FJt"M of the ball and the weight of the ball when a crack occurs in the molded object when it falls into the middle of a molded object with a thickness of 6.
, it was a commercial.

(Example 2) Freon/2 (Ccgz
F, molecule, 1/, 20.9, 7>'li point -, z
y,, r'c), 2. g weight rate % impregnated specific gravity /, /
The modified polyphenylene oxide was molded under the same molding conditions as in Example 1. The molded product obtained contained 1 uniform fine cell.
The foaming ratio was 2. In addition, no rust was observed on the mold at the 100 point I point, and even after the molding Ω hours had passed, there was no abnormality in the coating 11'4.
)is.

In addition, for the fallen November 141 student, Δ)- is gu03t・(7).
〕Ta.

(Real name column 3) 1. After putting the acid 1-1 polyphenylene oxide of Js EA y, / into the tank, 3 Ky / ctR
Conditions for O'C [Odor'C in its original state (7)'7L/on//II (CCeF*'-CC1!F1 molecule 17j/
70. 811 points 3. The material was impregnated with 1% Freon//'I, and molded under the same molding conditions as in Example 1. The obtained molded product had the same results as Example 1.2.

(Comparative Example 1) 100 parts by volume of modified polyphenylene oxide with a specific gravity of /, / were mixed with azocabonamide O0S in a tumbler, and molded under the same conditions as in Example 1. In addition, the molded product has uniform fine bubbles.The foaming ratio is 7.
．． However, after 100 shots were molded, rust occurred on the mold, and residual liquid was observed on the mold and molded product. When painted 2 hours after molding, numerous blisters were observed in the coating film. In addition, the falling ball impact 41 (gender is 2.2.
ff~・It was steel.

(Comparative Example 2) 700 parts by weight of modified polyphenylene oxide with a specific gravity of It is.

The obtained molded product had an expansion ratio of 7.2 times, but there were 11 large voids inside. Also, 100
No rust was observed on the mold after shot molding, but when it was painted 2 hours after molding, numerous small blisters appeared on the paint film. The ball impact resistance was as low as 22j9, and the molded product lacked hook resistance.

As described below, according to the method of the present invention, a blowing agent made of a halogenated hydrocarbon containing at least seven fluorine atoms is easily impregnated into the thermoplastic hatsumode.

Since the gasification rate of the blowing agent is low at room temperature and increases as the molding temperature increases, it is possible to obtain a molded product with uniform micro-cells, and the gas generated from the blowing agent also Good diffusion reduces waste removal time from foamed molded products, eliminates gas leaks during painting, and eliminates mold corrosion problems.7 Moreover, light heavy molding has good impact resistance. The product is Z, and it is a thing.

Claims (1)

[Claims] 1, '56 Preliminary addition of at least/more fluorine-containing halogenated hydrocarbons to the thermoplastic resin as a KjJ agent.
1. A method for stretching and forming a foam molded product, which is characterized in that the thermoplastic resin thus obtained is foamed and injection molded.