JPH01263134A - Rubber composition for mold cleaning - Google Patents

Abstract

PURPOSE:To obtain the title composition used in cleaning of mold for rubber molding, hardly causing bleeding phenomenon, having good workability and capable of providing excellent cleaning effect, by blending an unvulcanized rubber with an alkyl phenol and amino alcohol as a specific ratio. CONSTITUTION:15-30 pts.wt. alkyl phenol having at least one 7-11C alkyl and 2-8 pts.wt. amino alcohol such as 2-amino ethanol which are cleaning components and vulcanizer, vulcanization accelerator, reinforcing agent, etc., as others are added to 100 pts.wt. unvulcanized rubber, preferably using a natural rubber based material and the blend is kneaded to provide the aimed composition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rubber composition for cleaning molds used for cleaning molds used in rubber molding processes.

[Prior Art] Conventionally, methods such as sandblasting and alkaline solution cleaning have been used to clean the molds used in the rubber molding process, but these methods do not cause minute scratches on the molds. There were problems in that the molds had to be removed from the molding machine, resulting in poor workability. For this reason, a method has been proposed in which a rubber composition containing a cleaning component is placed in a contaminated mold and vulcanized to remove the contaminants adhering to the mold by transferring them to the vulcanized rubber. (For example, Japanese Patent Application Laid-open No. 122942/1983).

[Problems to be Solved by the Invention] By the way, conventional mold cleaning rubber compositions use amino alcohols such as aminomethyl ethanol, aminomethyl propatool, and triethanolamine as cleaning components. In this case, in order to ensure the cleaning effect, it is necessary to use a considerable amount of amino alcohol, and usually about 30 to 40 parts by weight of amino alcohol is used per 100 parts by weight of unvulcanized rubber.

However, when the blended amount of amino alcohol increases, the amino alcohol oozes out onto the rubber surface, which causes so-called bleed, making it difficult to handle. Furthermore, since amino alcohol gasifies during vulcanization and generates a pungent odor characteristic of amines, workability is significantly reduced.

The present invention was made in view of the above-mentioned circumstances, and an object of the present invention is to obtain a rubber composition for mold cleaning that does not cause bleeding, has good workability, and has an excellent cleaning effect.

[Means for Solving the Problems] As a result of intensive studies in view of the above circumstances, the present inventors have found that:
We discovered that by using alkylphenol as a cleaning ingredient in combination with amino alcohol, the same cleaning effect can be obtained even if the amount of amino alcohol used is reduced, and that bleeding can be improved and odor can be reduced. The present invention was completed based on this.

That is, the gist of the present invention is that 15 to 30 parts of alkylphenol is added as a cleaning component to 100 parts by weight of unvulcanized rubber.
The rubber composition for cleaning molds is characterized in that it contains amino alcohol in a ratio of 2 to 8 parts by weight and 1 part by weight.

In the present invention, any rubber material can be selected as the unvulcanized rubber that serves as the base, and specifically, natural rubber, styrene-butadiene rubber, chloroprene rubber, butadiene rubber, nitrile rubber, ethylene-propylene rubber,
Examples include synthetic rubbers such as polyisoprene rubber, butyl rubber, chlorosulfonated polyethylene, silicone rubber, and fluororubber. Furthermore, two or more of these may be used as a blend. From the viewpoint of strength, it is desirable to use a natural rubber material.

In the present invention, the alkylphenol blended into the unvulcanized rubber preferably has at least one alkyl group having 7 to 11 carbon atoms. Specifically, heptylphenol, octylphenol, nonylphenol, decylphenol, undecylphenol, p-nonylphenol, etc. are preferably used.

Specific examples of amino alcohols blended into unvulcanized rubber with alkylphenols include 2-aminoethanol, 3-amino-1-propatol, 4-amino-1-
Straight chain aliphatic amino alcohol such as butanol, 1-methyl-2-aminoethanol, 2-amino-1-methylethanol, 2-amino-1-ethylethanol, 1-amino-1,1-dimethylmethanol, 1. 1-dimethyl-2-amineethanol, 1-methyl-3-amino-1
-10 Branched aliphatic amino alcohol such as panol, 1-
Hydroxymethyl-2-aminoethanol, 2-amino-2-ethyl-2-hydroxymethylethanol, 1-
Amino-1,1-dihydroxymethylmethanol, 1-
Examples include hydroxyl-substituted branched aliphatic amino alcohols such as aminomethyl glycol, N-substituted amino alcohols such as triethanolamine, and the like.

The mixing ratio of these cleaning components is 15 to 30 parts by weight of alkylphenol and 2 to 8 parts by weight of amino alcohol per 100 parts by weight of unvulcanized rubber.

If the amount of alkylphenol is less than 15 parts by weight, the desired cleaning effect cannot be obtained. Further, if the amount is more than 30 parts by weight, bleeding of alkylphenol occurs. Furthermore, if the amount of amino alcohol is less than 2 parts by weight, the desired cleaning effect cannot be obtained, and if it is more than 8 parts by weight, bleeding may occur, which is not preferable.

In the present invention, these cleaning components include a vulcanizing agent, a vulcanization accelerator,
It is added to unvulcanized rubber together with other additives such as reinforcing agents, and kneaded in a conventional manner to prepare a mold cleaning rubber composition.

Cleaning of the mold is carried out by putting the obtained mold cleaning rubber composition into the mold to be cleaned, and molding and vulcanizing it in a conventional manner. At this time, contaminants adhering to the mold are transferred to the vulcanized rubber, and then removed together with the vulcanized rubber by opening the mold and taking out the vulcanized rubber.

[Examples] Hereinafter, the present invention will be explained in detail by examples, but the present invention is not limited by these examples unless the gist thereof is exceeded.

Example 1 To 100 parts by weight of a 70:30 blend of styrene-butadiene rubber and natural rubber, 25 parts by weight of p-nonylphenol, 5 parts by weight of 2-amino-2-methyl-1-propertool, and 55 parts by weight of silica were added. 1, 20 parts by weight of calcium carbonate, and 4 parts by weight of peroxide were mixed and kneaded to obtain a rubber composite acid for mold cleaning.

The obtained rubber composition was put into a mold that had been used for 10 hours in the molding process, and after vulcanization at 175 ° C for 10 minutes, the vulcanized rubber was removed from the mold and the state of adhesion of contaminants was examined. Ta.

The results are shown in Table 1 along with odor and bleeding properties. In addition,
The evaluation criteria and evaluation method were as shown below.

Evaluation criteria symbol Cleaning effect Odor Bleeding ○・・・・・・
Good None Small △...Yes Slightly present Medium ×...No effect Considerably present Great evaluation method Odor...Sensory evaluation by 3 workers Bleedability...・Surface bleed state normal physical properties after being left for one week...According to JIS K-6301,
The hardness Hs, tensile strength TB, and elongation EB were investigated.

Example 2 A mold cleaning test was conducted in the same manner as in Example 1, except that the blending ratio of p-nonylphenol was changed to 15 parts by weight. The results are also listed in Table 1.

In addition, in the same way, the blending ratio of p-nonylphenol or 2-amino-2-methyl-1-propanol was changed to the first
The results of cleaning tests conducted with the values changed to those shown in the table are shown as Examples 2 to 4 and Comparative Examples 1 to 3, respectively.

As is clear from the table, amino alcohol has a high cleaning effect when used alone, but has problems with bleeding and odor, and has poor workability (Comparative Example 1). On the other hand, alkylphenol alone has a low cleaning effect (Comparative Example 2), but when used in combination with amino alcohol, the same effect as amino alcohol alone can be obtained, and workability is greatly improved. It can be seen that physical properties such as tensile strength are also improved compared to Comparative Example 1.

[Effects of the Invention] The mold cleaning rubber composition of the present invention has a smaller amount of amino alcohol than conventional products, so it is less likely to cause a bleed phenomenon and has less odor. Therefore, workability is improved, and furthermore, it has an excellent cleaning effect and is highly practical. Furthermore, the strength has been dramatically improved, and it has the advantages of being resistant to breakage, easy to handle, and easy to remove from the mold.

Claims (1)

[Claims] 1. A rubber composition for cleaning molds, which contains 15 to 30 parts by weight of alkylphenol and 2 to 8 parts by weight of amino alcohol as cleaning components to 100 parts by weight of unvulcanized rubber.