JPS61287946A - Rubber composition for mold cleaning - Google Patents

Abstract

PURPOSE:To provide the titled compsn. which allows deposited contaminants to be removed without taking out the mold, by adding an aliph. aminoalcohol and a metal chelating agent to a general-purpose rubber compsn. CONSTITUTION:A mixture of 5-30pts. aliph. aminoalcohol having a 2-4C straight-chain or branched alkyl group and 1-40pts. metal chelating agent selected from among aliph. amines contg. at least two amino groups, urea and aminocarboxylic acids is blended with 100pts. general-purpose rubber compsn.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a rubber composition for cleaning molds,
In particular, the purpose is to improve unvulcanized rubber compositions in which contaminants are removed by performing molding operations similar to normal vulcanization molding without removing molds contaminated by rubber molding. be.

<Conventional technology> Traditionally, the removal of rubber or synthetic resin attached to a mold has been done by
There are physical methods using sandblasting and wire brushing, chemical methods that treat the mold with caustic soda or sulfuric acid, methods that spray flames generated by gas combustion, and others.
There are electrolysis methods, ultrasonic cleaning methods, steam spraying methods, etc. In addition, there is a method using a mold cleaner that removes contaminants by spraying a compound containing an amino group and a hydroxyl group in the same molecule onto the mold, which is considered to be a type of chemical method, and a method using a mold cleaner that removes contaminants by using this as a rubber composition. There is a method to remove contaminants by molding them into one piece.

Physical methods have disadvantages of damaging the mold and not being able to remove every corner of the mold, so recently, the latter chemical method is often used.

A method of removing contaminants adhering to the mold using a rubber composition has been proposed for some time, for example, in US Pat. No. 3,476,599 (November 4, 1969). Although many proposals have been made in Japan (for example, Japanese Patent Application Laid-open No. 1229-1989)
No. 42), both are similar technologies.

<Problems to be Solved by the Invention> Such conventionally proposed mold cleaning rubber compositions have a problem in that the bond between the mold metal and its surface contaminants is weakened by the compound having an amino group and a hydroxyl group. However, in reality, the purification effect cannot be expected to be that great. In particular, conventional mold cleaning rubber compositions are hardly able to decontaminate metal compounds such as lead compounds and zinc compounds that adhere to the mold.

<Means for Solving the Problems> Therefore, the present inventor conducted various studies on the components and decontamination mechanism of the rubber composition for mold cleaning. As a result, a mold made of a mixture of 5 to 30 parts of an aliphatic amino alcohol having a straight chain or branched alkyl group having 2 to 4 carbon atoms and 1 to 40 parts of a metal chelate and other agents per 100 parts of a general-purpose rubber composition. They developed a cleaning rubber composition.

In the composition of the present invention, when the mold contaminants are rubbers containing lead compounds, such as epichlorohydrin rubber, chloroprene rubber, and other special rubbers, the metal chelating agent is an aliphatic amine having two or more amino groups. ,
Preferably, one or a mixture of two or more selected from urea, aminocarboxylic acids, and the like. Salicylic acid is also preferred for staining general rubber that does not contain lead compounds.

Effect> The mold cleaning rubber composition with the above structure completely removes contaminants from the mold due to the synergistic effect of the amino alcohol and the metal chelating agent, compared to conventional rubber compositions containing only aliphatic amino alcohol. will be removed. In particular, metal stains are effectively decontaminated by forming metal chelates.

The present invention will be described in detail below with reference to Examples.

<Example> Diene rubber compositions for cleaning molds having compositions shown in Nos. 1 to 5 in Table 1 below were prepared. Comparative example No. 1
and No. 2 correspond to conventional products.

Each composition was made by mixing a general-purpose rubber composition consisting of SBR, stearic acid, silicic acid, and a peroxide vulcanizing agent by a known method, adding N-propanolamine, which is an amino alcohol, and then adding Different metal chelating agents were added to form unvulcanized (green) rubber.

Table 2 shows the results of testing the contamination removal effect using the mold cleaning rubber composition having the above composition.

The test used a mold for contamination analysis, and a 5S41 contamination test metal fitting (1 nn x 10 mwφ) was set inside the mold, and the diene rubber for contamination (composition shown in Table 3) was vulcanized at 160°C for 30 minutes. was molded 30 to 60 times, and the contamination test fittings were taken out and analyzed for notable contamination components using an X-ray microanalyzer (EPMA).

This test revealed that carbon, zinc oxide, silicon oxide, and sulfuric acid radicals have a large decontamination effect, and in particular, the decontamination effect of zinc oxide is significantly greater than that of the comparative examples. . Regarding iron, when the mold is dirty, the count appears to be small, but due to the decontamination effect of the present invention, a large count is obtained.

Table 3: Diene rubber formulation for contamination test (parts) Next, a decontamination test was conducted using chlorine-containing rubber for contamination test containing lead. The formulation of the molding rubber composition used in the test is shown in Table 4.

Table 4: Chlorine-containing rubber formulation for contamination test (parts) Using a contaminant analysis mold, set the 5S41 contamination test fitting inside the mold as described above, and vulcanization conditions: 160°C, 10
It was molded 30 times in 1 minute and caused contamination.

Next, the contamination test fitting was taken out and analyzed for contamination components of interest using an X-ray microanalyzer as described above. The results are shown in Table 5.

As is clear from the analysis results, the decontamination efficiency of zinc and lead is very high, and the removal efficiency of metal contamination is particularly good as is clear compared to the comparative example of conventional products. The same applies to non-metal contamination.

Furthermore, an example in which the metal chelating agent is salicylic acid will be described. Table 6 shows the composition of the mold cleaning rubber composition. The staining rubber composition for the test was the same as that in Table 3 above. The vulcanization molding conditions were 160° C. and 30 minutes. The test method was the same as before, and the contaminated mold was removed once or twice with a cleaning rubber, and the results are shown in Table 7. It shows better decontamination effects than conventional products for all contaminant components.

<Effects of the Invention> Since the present invention is a mold cleaning rubber composition as detailed above, it does not contain organic substances, chlorine, sulfur compounds, zinc compounds, and mold surfaces that are generated during molding of general-purpose diene rubber. Oxides, etc. can be removed without removing the mold.

Below margin

Claims (1)

[Scope of Claims] 1. 5 to 30 parts of an aliphatic amino alcohol having a straight chain or branched alkyl group having 2 to 4 carbon atoms, and 1 to 40 parts of a metal chelating agent per 100 parts of a general-purpose rubber composition. A rubber composition for cleaning molds, which is prepared by adding a mixture of. 2. The metal chelating agent according to claim 1, consisting of one or a mixture of two or more selected from aliphatic amines having two or more amino groups, urea, aminocarboxylic acids, etc. Rubber composition for mold cleaning. 3. The mold cleaning rubber composition according to claim 1, wherein the metal chelating agent is salicylic acid.