JPH0718122A - Rubber compound for mold cleaning use - Google Patents

Abstract

PURPOSE:To obtain a rubber compound for mold cleaning use, capable of getting a definite stable cleaning effect even without using stenchy amino alcohol and expected to get an improved cleaning effect by the combined use of an amino alcohol. CONSTITUTION:This rubber compound for the cleaning of a mold is incorporated with a mold cleaning agent. It is poured into a mold and vulcanized to transfer the stains from the mold cavity surface to the formed vulcanized rubber to effect the cleaning of the mold. A hydroxybenzoic acid ester is used as at least a part of the mold cleaning agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a mold cleaning agent, which is injected into a mold and vulcanized to transfer contaminants on the mold cavity surface to a vulcanized rubber molded product. The present invention relates to a rubber compound for mold cleaning which performs mold cleaning.

[0002]

2. Description of the Related Art Amino alcohol is the mainstream as a mold cleaning agent in the above-mentioned type of rubber composition for mold cleaning. (See JP-A-58-122942).

In response to the recent demand for improving the mold cleaning power, it has been proposed to use a metal chelating agent such as amino alcohol and salicylic acid (o-hydroxybenzoic acid ester) as a mold cleaning agent. (JP-A-61-
287946).

However, since all of them contain amino alcohol, it has been found that they have a strong odor and that it is difficult to obtain a stable cleaning effect even when they are used together with a metal machine rate agent.

The above-mentioned contaminants are organic chemicals contained in general-purpose rubber compounds, sulfur / zinc / chlorine compounds, and
The main component is metal oxide on the surface of the mold.

[0006]

SUMMARY OF THE INVENTION In view of the above, the present invention provides a constant and stable cleaning effect without using an amino alcohol that produces a foul odor. Another object of the present invention is to provide a rubber compound for mold cleaning which can be expected to have an increased cleaning effect.

[0007]

Means for Solving the Problems As a result of intensive efforts to solve the above problems, the present inventors have conceived a rubber composition for mold cleaning having the following constitution.

Mold cleaning in which a mold cleaning agent is blended, and by pouring into a mold and vulcanization molding, contaminants on the mold cavity surface are transferred to a vulcanized rubber molded product to perform mold cleaning. In the rubber compound for use, hydroxybenzoic acid ester is compounded as all or a part of the mold cleaning agent.

[0009]

Detailed Description of Means Hereinafter, the means of the present invention will be described in more detail. In the following description, a compounding unit is a weight unit unless otherwise specified.

(1) The rubber component of the rubber compound used in the present invention is not particularly limited, and all commercially available products can be applied.

Specifically, natural rubber (NR), natural synthetic rubber (IR), styrene-butadiene rubber (SBR), butadiene rubber (BR), chloroprene rubber (CR), butyl rubber (IIR), nitrile rubber (NBR). , Ethylene propylene rubber (EPM, EPDM), chlorosulphonated polyethylene (CSM), epichlorohydrin rubber (CO, ECO), acrylic rubber (ACM, ANM,
Examples thereof include ABR), urethane rubber (U), silicone rubber (Q), fluororubber (FKM), and the like.

(2) A rubber compound to which the present invention is applied includes, in addition to a mold cleaning agent, a reinforcing filler, stearic acid, a vulcanizing agent and the like used in a rubber compound having a general vulcanization formula. Is blended.

(3) The present invention is characterized in that the hydroxybenzoic acid ester is blended as the whole or a part of the mold cleaning agent.

The hydroxybenzoic acid ester may be a meta-form or a para-form, but a salicylic acid ester is preferable although it is an ortho-form because of its chelating action and availability. Examples of salicylates include benzyl salicylate, isoamyl salicylate, ethyl salicylate, methyl salicylate, and the like.

The compounding amount of hydroxybenzoic acid ester is
5 to 100 parts of rubber polymer when used alone
The amount is 30 parts (desirably 15 to 25 parts). If the amount is too small, the mold cleaning action is difficult to be achieved, and if the amount is too large, the cleaning power is insufficient due to foaming of the vulcanized rubber, and the mold releasability is easily deteriorated.

Further, as the other mold cleaning agent used in combination when the hydroxybenzoic acid ester is used as a part of the mold cleaning agent, amines such as aminoalcohol, triethylenetetramine, propylenediamine and the like can be mentioned. it can.

Of these, an aliphatic amino alcohol having a linear or branched alkyl group having 3 to 4 carbon atoms is preferable, and N-propanolamine, N-ethylethanolamine, 2-amino-2-methylpropanol and the like are preferable. Can be mentioned.

When the hydroxybenzoic acid ester and the amino alcohol are used in combination, the amount of the mold cleaning agent is 3 to 2 with respect to 100 parts of the rubber polymer.
It is 0 part (desirably 5 to 25 parts). If the amount of both chemicals is too small, the mold cleaning effect is difficult to exert, and if the amount is too large, the former case is likely to cause insufficient cleaning power due to foaming of the vulcanized rubber and the mold release property is deteriorated. The bad odor is strong, which is not desirable.

(4) In the rubber composition for mold cleaning of the present invention, the rubber polymer, the mold cleaning agent, various fillers such as a reinforcing filler, a vulcanizing agent and a softening agent are weighed. And blended, Banbury mixer, Intermix,
The dough is kneaded through a kneading step of mixing with a kneader or other closed type kneader or a kneading roll or other kneader. And
The kneaded material is poured into a contaminated mold by injection, transfer, etc., and vulcanization molding is performed to clean the mold.

[0020]

The action and effect of the invention The rubber compound for mold cleaning according to the present invention has the following action by incorporating the hydroxybenzoic acid ester as all or a part of the mold cleaning agent as described above.・ To be effective.

(1) Even without using amino alcohol,
A constant and stable cleaning effect can be obtained. The reason is presumed to be as follows.

The hydroxyl group of hydroxybenzoic acid ester is
A vulcanized rubber molded product is obtained by weakening the adhesion of contaminants bonded to the surface of the mold to the surface of the mold, and wrapping the hydroxybenzoic acid ester in the contaminants with weakened adhesion by a coordinate bond. The effect of shifting to. Then, at this time, the hydroxybenzoic acid ester is more compatible with the rubber compound than salicylic acid, and has the effect of reliably transferring the contaminants to the vulcanized rubber molded product.

(2) When amino alcohol is used in combination,
The amount of amino alcohol used can be reduced and the cleaning effect can be expected to increase.

Amino alcohol has the effect of weakening the adhesion of contaminants to the mold surface, and when used in combination with the above hydroxybenzoic acid ester, the synergistic effect produces a malodorous amino alcohol with a small amount. A large cleaning effect can be expected.

[0025]

[Test Example] Hereinafter, a test example carried out to confirm the effects of the present invention and carried out for Examples and Comparative Examples will be described.

(1) Preparation of Samples In the following basic compounding recipe, the mold cleaning agents shown in Table 1 were compounded in the indicated amounts, and the rubber compounds of Examples and Comparative Examples were obtained according to the compounding recipe. It was

EPDM compounding formulation EPDM * 1) 100 parts Stearic acid 1 part Silica 40 parts Dicumyl peroxide 9 parts Mold cleaning agent Variable * 1) C2 content: 56%, iodine value: 17, third component:
Ethylidene norbornene First, each compounding agent was mixed with a 1.7 L closed type kneader to obtain a sample (kneaded dough of rubber compounding).

(2) Test Method The following items were tested and each sample was collected and analyzed according to the method.

Mold washability: Each of the above samples was injected into a contaminated mold and vulcanized and molded at 190 ° C. for 3.5 minutes. Then, the gloss value on each mold cavity surface was measured with a "digital gloss meter GK60D" (manufactured by Suga Test Instruments Co., Ltd.) to evaluate the washability.

Odor: At the time of the mold cleaning test, an odor sensor was placed on the cleaned rubber after molding and measured with "semiconductor scent sensor NS720" (manufactured by Keyence Corporation) to evaluate the odor. .

Smoke generation amount: The sample was kept in an atmosphere of 100 ° C. for 5 minutes, and the heating loss at that time was measured to be used as an evaluation standard of the smoke generation amount. Smoke is a major alienation factor of the work environment together with odor.

(3) Test Results and Evaluation From Table 1 showing the test results, Examples 1 to 3 in which salicylic acid ester is used alone have a higher odor and smoke generation amount than Comparative Example 1 in which amino alcohol is used alone. It can be seen that not only is it significantly less, but the washability is superior and inferior.

Further, in Examples 4 to 6 in which the salicylic acid ester and the amino alcohol are used in combination, the amount of odor / smoke is increased as compared with Examples 1 to 3, but the cleaning property is relatively excellent, Further, it can be seen that the detergency is excellent as compared with Comparative Example 2 in which salicylic acid and amino alcohol are used in combination.

[0034]

[Table 1]

Claims (2)

[Claims] 1. A metal mold containing a mold cleaning agent, which is injected into a mold and vulcanized to transfer contaminants on the mold cavity surface to a vulcanized rubber molded product for mold cleaning. A rubber composition for mold cleaning, wherein a hydroxybenzoic acid ester is compounded as a whole or a part of a mold cleaning agent in the rubber composition for mold cleaning. 2. The rubber composition for mold cleaning according to claim 1, wherein the mold cleaning agent is a combination system of hydroxybenzoic acid ester and amino alcohol. .