KR930011264B1 - Method for forming molded articles used with light weight - Google Patents

Abstract

A method for molding a body using a light aggregate comprises (1) making a composition by adding 1˜100 wt% a setting accelerator having piperazin:alkanol amine at 1:(1˜8) to a mixture of polyoxyalkylene polyamine R?(OA)xNH2?y (R: hydrocarbon radical, A:C2-C4 alkylene radical, x:1˜10 constant, y:2˜4 constant) with poluglycidylether of multi-valence hydogen phenol, (2) forming a surface layer by charging the composition into the bottom of a mold, (3) covering on the surface layer with some thickness by mixing light aggregate/molded body at (3.5˜ 5):1, (4) removing foams by vibrating the mold, (5) flatizing with a roller, and (6) after maintain for 30 minutes, thermal setting in the temperature range of 60˜80≰C for about 20 minutes.

Description

Molding method of molded body using lightweight aggregate

The present invention relates to a molding method of a molded body using a lightweight aggregate. In particular, the present invention relates to an epoxy molded article used for molding and a method for molding a molded article using lightweight aggregate together with it.

Epoxy resins are very versatile among various resins. For example, epoxy resins may be used for molding molded articles using lightweight aggregates such as gravel. In such a molded article, it is important to have no cracking resistance, chemical resistance, and excellent physical properties such as tensile and tear strength. Among these, it is particularly important that no crack appears on the surface of the molded body after molding.

Therefore, although various molded compositions have been proposed in view of such a problem, it was not satisfactory to prevent surface cracking due to shrinkage when molded into molded bodies. In addition, the surface flatness was not uniform even when molded using lightweight aggregate. This is because there is a problem in the selection of a curing agent, a curing method and other additives used in the epoxy resin, it appears that these several do not work synergistically with each other. Among them, the most important problem is the selection and curing method of the appropriate curing agent. Therefore, several methods have been proposed to solve the problem of curing.

U.S. Patent No. 3,462,393 describes the use of polyoxyalkylene polyamines to cure polyglycidyl ethers of polyhydrogenphenols. In addition, US Pat. No. 2,783,214 describes a method of curing the most commonly used epichlorohydrin-bisphenol moldings using an amine curing agent of triethylenetetramine and triethanolamine at ambient temperature. However, in the case of these patents, the epoxy resin is cured at ambient temperature. In the case of such a low-temperature curing epoxy resin, physical properties are inferior. In addition, even when using the molded body with a lightweight aggregate using the belt type is mainly used, but the loss is too much and has the disadvantage of poor quality.

In addition, there is a method using a mold, but this method also has a drawback in that bubbles are formed in the molded body or the surface is not smooth.

Accordingly, an object of the present invention is to solve the above problems of the prior art, by adding a curing accelerator of piperazine and alkanolamine to a mixture of polyoxyalkylene polyamine and polyglycidyl ether of polyhydric phenol type. It is to provide a molded body composition, and to provide an improved method of molding a molded body using such a molded body composition.

The present invention relates to a method of curing and promoting a polyglycidyl ether of a polyhydric phenol cured with a polyoxyalkylene polyamine, which method comprises a composition in which the composition ratio of piperazine: alkanolamine is 1: 1 (1-8). Stoichiometrically mixing the polyoxyalkylenepolyamine of the promoter with the polyglycidyl ether of the polyhydrogenphenol, and then curing the resulting molded body composition.

As for the polyglycidyl ether of the polyhydric phenol used by this invention, the diglycidyl ether of isopropylidene phenol is preferable.

In addition, the polyoxyalkylene polyamine used by this invention has the following general formula.

R [(OA) _y NH ₂ ] _y

Wherein R is a hydrocarbon radical, A is a C ₂ -C ₄ alkylene radical, x is a number from 1 to 10 and y is a number from 2 to 4 representing the valence of R.

As the polyoxyalkylene polyamine represented by the above general formula, an amine compound having the following general formula (I), (II) or (III) is preferably used.

In addition, alkanol amines that can be used in the present invention are mono-, di- or triethanolamine, hydroxy ethoxyethylamine, N-aminoethanolamine, N, N-bis- (hydroxypropyl), N-hydroxy Ethylamine and the like are preferred.

There is no particular order for mixing the above mentioned components, but the polyoxy alkylenepolyamine, piperazine and alkanolamine components are mixed to obtain a uniform curing accelerator mixture, and then the resulting mixture is mixed with the resin components described above. The resin is prepared by self curing at ambient temperature.

In the present invention, it is preferable to first mix the piperazine and the alkanol amine component, then add the resulting mixture to the polyoxyalkylene polyamine component, and finally mix the entire mixture with the cured resin component described above. The piperazine and alkanolamine components mixed here can be stored and used for a long time.

In carrying out the present invention, it is preferable that the combination of piperazine and alkanolamine components has a composition ratio of piperazine: alkanolamine of about 1: (1-8). In the present invention, it has been found that the combination of the above ratios exhibits a great synergistic effect in promoting self curing of the epoxy resin cured with polyoxyalkylenepolyamine at ambient temperature. Accordingly, it has been found that the rate of cure at ambient temperature is greatly reduced when piperazine or alkanol amines are used alone, or when the components are used outside of the above mixing ratio.

The curing accelerator of piperazine and alkanol amines is preferably used in an amount of about 1 to 100 parts by weight based on 100 parts by weight of polyoxyalkylenepolyamine. The optimum amount here varies with the given application conditions according to the epoxy resin, polyoxyalkylenepolyamine.

When curing the epoxy resin, it is preferable to use a curing accelerator in an amount capable of providing one reactive -NH per epoxy group in the epoxy resin component. Epoxy resin products obtained by curing epoxy resins with polyoxyalkylene polyamines using a curing accelerator of piperazine and alkanolamine can be used in various ways such as flooring materials, molding agents, encapsulating agents, pressure-sensitive adhesives, protective coating agents, and the like.

In addition to the above-mentioned components, it is preferable to use flame retardants, which include halogenated compounds and phosphate compounds including piperazine phosphate, which should be used to such an extent that they do not adversely affect the hardening of alkanol amines and piperazine.

The molding agent combinations thus far consisting of epoxy resins, polyoxyalkylenepolyamines and accelerators of piperazine and alkanol amines are preferably self-curing in the temperature range of 0 to 45 ° C. On the one hand, the above mixture can be post-cured as needed at a temperature of 175 ° C.

According to this invention, the above molding agent composition is administered to the mold bottom to form a surface layer, and a light aggregate / molding agent composition such as gravel is mixed at a ratio of (3.5-5): 1 to cover the surface layer with a predetermined thickness, and the mold Vibration was applied to remove the bubbles, flattened using a roller, left for about 30 minutes, and then heat-cured at a temperature of 60 to 80 ° C for about 20 minutes. At the time of shaping | molding, a certain shape can be shape | molded with a molded object, and the other hardening methods are the same as before.

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

[Examples 1 to 4]

To prepare an epoxy resin composition as shown in Table 1 at a temperature of about 25 ℃. The stoichiometrically equivalent amount of the epoxy resin of the curing agent consisting of polyoxyalkylenediamine, with or without additional promoter components, is then mixed in each example. A portion of each composition is applied to a steel test panel at a thickness of 6 mils and cured at room temperature. As shown in the gel time and drying time of Example 4, the use of piperazine and alkanol amines as curing accelerators showed a strong synergistic effect in promoting the curing rate of epoxy resins cured with polyoxyalkylene-polyamines. have.

TABLE 1

1.Diglycidyl ether of isopropylidenediphenol.

2. Jeffamine (brand name) of Jefferson chemical.

3. Triethanol amine.

4. Piperadine.

5. Time to reach set-to-touch (touch-to-touch time).

6. TD (through dry).

In the above table, STT (指 觸 乾燥) refers to a dry state in which the fingerprint is not touched even if a finger lightly touches the coating film, and TD means a state that is completely cured, that is, the reaction is completely cured.

[Examples 5 to 8]

In the same manner as in Examples 1 to 4 to prepare an epoxy resin composition of Table 2. It can be seen that the strong synergistic effect is shown in Example 8 in which piperazine and triethanolamine are mixed.

TABLE 2

1. Same as Table 1

2. Polyoxypropylenediamine, Jeffamine (trade name) with an average molecular weight of 400.

3. Triethanol amine.

4. Piperazine.

Example 9

The epoxy resin composition prepared in Examples 1 to 8 is mixed with the lightweight aggregate to form a molded body. First, the epoxy resin composition of Example 1-8 is administered to the bottom of the mold to form a surface layer, and then the lightweight aggregate / epoxy resin (3.5-5): 1 is mixed and poured on the surface layer at a constant thickness. Then, the rollers are used to give flatness and to stand for 30 minutes to remove bubbles from the inside. Although hardening progresses at this time, since hardening takes long, it hardens for 20 minutes, heating at 60-80 degreeC.

The molded article produced here had a smooth surface and no loss at all.

Claims (4)

To a mixture of polyoxyalkylene polyamines having the following general formula of polyglycidyl ethers of stoichiometric mixed polyhydric phenols, a curing accelerator having a composition ratio of piperazine: alkanolamine of 1: (1-8) Add 1 to 100 parts by weight per 100 parts by weight of the oxyalkylene polyamine to make a molding composition, administer the molding composition to the mold floor to form a surface layer, and the lightweight aggregate / molding composition (3.5-5): Mixing at a ratio and covering the surface layer with a predetermined thickness, applying vibration to the mold to remove bubbles, giving flatness using a roller, leaving it for about 30 minutes, and heat curing at a temperature of 60-80 ° C. for about 20 minutes. Forming method of the molded body using a lightweight aggregate consisting of. R [(OA) _y NH ₂ ] _y Wherein R is a hydrocarbon radical, A is a C ₂ -C ₄ alkylene radical, x is an integer from 1 to 10 and y is an integer from 2 to 4 representing an atomic group of R. 2. The method for forming a molded product according to claim 1, wherein the polyglycidyl ether of polyhydric phenol is diglycidyl ether of isopropylidene phenol. The method for forming a molded product according to claim 1, wherein the polyoxyalkylene polyamine is an amine compound represented by the following general formula (I), (II) or (III).

The compound of claim 1, wherein the alkanolamine is mono-, di- or triethanolamine, hydroxyethoxyethylamine, N-aminoethanolamine, N, N-bis- (hydroxypropyl) or N-hydroxyamine. Forming method of a molded body characterized by.