JPH05154850A - Mold washing rubber composition - Google Patents

Abstract

PURPOSE:To markedly enhance mold washing effect by using a mold washing rubber composition prepared by compounding aminoalcohol, glycols and an adsorbent. CONSTITUTION:A mold washing rubber composition is obtained by compounding 2-30 pts.wt. of aminoalcohol, 5-50 pts.wt. of glycols and 30-90 pts.wt. of an adsorbent with 100 pts.wt of rubber composed of natural rubber or synthetic rubber. As the adsorbent, at least one kind of a substance selected from silica, active alumina, activated carbon, bentonite and diatomaceous earth is used. This rubber composition is formed into a sheet like form to be bonded to the surface of an unvulcanized rubber product and vulcanizing operation is performed to wash a vulcanizing mold. Therefore, the mold can be washed without being detached from a vulcanizer for the purpose of washing or damaged and productivity is enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold cleaning rubber composition used for cleaning a mold whose surface is contaminated by repeated vulcanization.

[0002]

2. Description of the Related Art Contamination of vulcanization molds has been known for a long time in the rubber molding industry, and mold pollution is promoted in the vulcanization process along with the frequency of use, and the quality of rubber molded products is There are problems such as giving a serious defect to the product such as appearance and dimensional accuracy, shortening the mold releasability from the mold, and shortening the life of the mold.

Therefore, many studies have been made so far as countermeasures for mold contamination, for example, Japanese Patent Publication No. 59-4498.
No. 0, a method of adding an organic phosphoric acid ester or a cyclopentadiene derivative carboxylate salt to an outer surface liquid, and a compound having a silicon and an isocyanate group in the molecule described in JP-A No. 62-113518. As a method of surface-treating the mold with the method described above, or a method of reducing the contamination of the mold by blending a specific substance in the rubber composition to be molded, cyclized polybutadiene (JP-A-54-6).
3144), organic phosphoric acid ester salt (Japanese Patent Publication No. 57/57)
-53812), mercaptobenzo-1,3-diazole salt (JP-A-54-107943), cyclopentadiene derivative carboxylic acid metal salt (JP-A-54-54).
126251), 2-mercaptobenzimidazole or its zinc salt (Japanese Patent Publication No. 61-20585) or specific silica (hydrous silicic acid, JP-A No. 63-
No. 238143) and the like have been proposed to improve the mold contamination.

However, although these methods can delay the pollution, they cannot completely prevent the pollution. Therefore, periodical mold cleaning, such as shot blasting method using glass beads, acid and alkali cleaning, etc. are performed, but these mold cleaning damage the mold and accelerate the subsequent contamination rate, In addition to corroding the mold, the mold must be removed from the vulcanizer for cleaning, especially for large rubber products, the man-hours can not be ignored and productivity is reduced. was there.

As a method for cleaning the mold without removing it from the vulcanizer, a method of using a rubber composition containing amino alcohol as a cleaning rubber in JP-A-58-122942, or a method of using these amino alcohols or A method in which a cleaning liquid prepared by dissolving amino alcohol in ethanol or the like is applied to the surface of a contaminated mold and then the unvulcanized rubber composition is vulcanized by a usual method and washed (JP-A-58-180).
No. 600) and the like, and many other rubber compositions for exclusive use in mold cleaning are generally on the market. However, although they have some effects, they are still insufficient, and these cleaning rubber compositions are also known. Almost all of them contain a large amount of amine-based chemicals that are easily decomposed, so they give off an ammonia odor even at room temperature, corrode the mold due to the generation of more amine after heating, and Also had a problem.

[0006]

The object of the present invention is not only to blend the rubber composition itself to be molded to delay the contamination of the mold, but also to remove the mold and wash it by shot blasting or the like. A rubber that cleans the mold by molding a rubber composition dedicated to mold cleaning without removing the mold from the vulcanizer, which requires a large number of steps and does not damage the surface of the mold. (EN) It is intended to provide a mold cleaning rubber composition which is a composition and does not corrode the mold or deteriorate the working environment like the conventional one.

[0007]

[Means for Solving the Problems] The inventors of the present invention have conducted earnest studies to solve the above-mentioned problems, that is, the problems of damaging, corroding the mold, and contaminating the working environment. As a result, they have found that a rubber composition containing an amino alcohol, a glycol and an adsorbent has a remarkable cleaning effect, and completed the present invention.

That is, the present invention is as follows: (1) 2 to 30 parts by weight of amino alcohol, 5 to 50 parts by weight of glycols, and 30 to 30 parts of adsorbent per 100 parts by weight of rubber made of natural rubber and / or synthetic rubber.
A mold cleaning rubber composition containing 90 parts by weight,

(2) The amino alcohol is monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, N, N-dimethylethanolamine, N, N-dibutylethanolamine,
N, N-diethylethanolamine, N-methyl-N,
The mold cleaning rubber composition according to item 1, which is at least one selected from the group consisting of N-diethanolamine, 2-amino-2-methylpropanol, 3-aminopropanol and 2-aminopropanol,

(3) The glycols are ethylene glycol, diethylene glycol, triethylene glycol,
The mold cleaning rubber composition according to item 1, which is at least one selected from the group consisting of propylene glycol and dipropylene glycol,

(4) The mold according to item 1, wherein the amino alcohol is at least one selected from the group consisting of monoethanolamine, diethanolamine, 2-amino-2-methylpropanol, 3-aminopropanol and 2-aminopropanol. A cleaning rubber composition,

(5) The mold cleaning rubber composition according to the above item 1, wherein the glycol is diethylene glycol and / or dipropylene glycol,

(6) The content of amino alcohol is 5 to 20 parts by weight based on 100 parts by weight of rubber.
A mold cleaning rubber composition as described above,

(7) The content of glycols is 1
The mold cleaning rubber composition according to the above item 1, which is 10 to 30 parts by weight with respect to 00 parts by weight,

(8) The adsorbent is silica, activated alumina,
The mold cleaning rubber composition according to item 1, which is at least one selected from the group consisting of activated carbon, magnesium oxide, titanium oxide, calcium carbonate, bentonite, and diatomaceous earth.

(9) The mold cleaning rubber composition according to the above item 1, wherein the adsorbent is silica.

(10) The mold cleaning rubber composition as described in the above item 1, wherein the adsorbent content is 40 to 70 parts by weight.

(11) The mold-cleaning rubber composition as described in 1 above, wherein 2 to 20 parts by weight of water is mixed with 100 parts by weight of rubber.

In the rubber composition of the present invention, as the rubber, a single rubber or a blended rubber arbitrarily selected from natural rubber and various synthetic rubbers can be used. Specific examples of the synthetic rubber include synthetic polyisoprene rubber and styrene-butadiene copolymer. Polymerized rubber, polybutadiene rubber, butyl rubber, halogenated butyl rubber, ethylene propylene terpolymer and the like can be used, but the present invention is not limited thereto.

In the rubber composition of the present invention, amino alcohol means monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, N, N-dimethylethanolamine, N, N-dibutylethanolamine, N, N -Diethylethanolamine, N-methyl-N, N-diethanolamine, 2-
Amino-2-methylpropanol, 3-aminopropanol, 2-aminopropanol and the like, preferably monoethanolamine, diethanolamine, 2-amino-2-methylpropanol, 3-aminopropanol and 2-aminopropanol. May be used alone or in combination of two or more. The compounding amount is 2 to 30 parts by weight, preferably 5 parts by weight with respect to 100 parts by weight of rubber.
-20 parts by weight. If the compounding amount is less than 2 parts by weight, the effect of cleaning the mold is not sufficient, and if it exceeds 30 parts by weight, the breaking strength of the rubber composition decreases, and the cleaning rubber composition is used when the rubber composition is taken out after cleaning the mold. Is cut off on the way and remains in the mold, and not only the cleaning effect is deteriorated, but also excess amino alcohol remains on the mold surface, which is not preferable.

In the rubber composition of the present invention, glycols include ethylene glycol, diethylene glycol,
Triethylene glycol, propylene glycol, dipropylene glycol and the like are preferable, and diethylene glycol and dipropylene glycol are preferable, and these may be used alone or in combination of two or more kinds. The compounding amount is 5 to 50 parts by weight, preferably 10 to 30 parts by weight, based on 100 parts by weight of rubber. If the compounding amount is less than 5 parts by weight, the mold cleaning effect is not sufficient, and if it exceeds 50 parts by weight, not only the effect of increasing the amount is not obtained, but also the breaking strength of the rubber composition is lowered and the mold cleaning effect is deteriorated. Not only
Excessive glycols remain on the mold surface, which is not preferable.

Further, in the rubber composition of the present invention, an adsorbent is blended in order to remove the contaminants from the surface of the mold. Examples of the adsorbent include silica, activated alumina, activated carbon, magnesium oxide, titanium oxide and carbonic acid. Magnesium, calcium carbonate, bentonite, diatomaceous earth, etc. are used, but when the rubber composition is taken out after washing the mold, if the mold has a complicated shape, the rubber composition will be cut off in the middle, Resilient silica is preferably used because it may remain in the mold. Further, the compounding amount is 30 to 90 parts by weight, preferably 40 to 70 parts by weight with respect to 100 parts by weight of rubber. If the compounding amount is less than 30 parts by weight, the breaking strength of the rubber composition is low and the contaminants cannot be completely stripped off, and if it exceeds 90 parts by weight, the viscosity of the rubber composition becomes too high, which results in cleaning. At this time, the rubber does not flow to the details of the mold, and as a result, the uncleaned portion remains, which is not preferable.

In the rubber composition of the present invention, water may be added in order to further enhance the cleaning effect. The blending amount is 2 to 10 parts by weight. If the compounding amount is less than 2 parts by weight, the effect of addition is not obtained, and if it exceeds 20 parts by weight, not only the effect of increasing the amount is no longer present, but also the kneading workability of the rubber composition is deteriorated, which is not preferable.

In the rubber composition of the present invention, fillers such as carbon black usually used in the rubber industry, softening agents such as aroma oil and naphthenic oil, vulcanizing agents such as sulfur and vulcanization accelerators, and aging are used. Inhibitors and the like can be added as needed.

The rubber composition of the present invention is preferably used for cleaning a mold for vulcanizing all rubber products including tires. Further, the cleaning method is to prepare a cleaning rubber composition in a shape similar to that of an unvulcanized rubber product and carry out by a normal vulcanization operation. At this time, the cleaning rubber composition is, for example, about 1 to 5 mm. It may be vulcanized by sticking it to the surface of an unvulcanized rubber product in the form of a sheet, and this will prevent excess amino alcohol and glycols from remaining on the surface of the mold after cleaning. It is preferable because the problem of contaminating the mold is eliminated.

[0026]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Various rubber compositions having the compounding contents shown in Table 1, Table 2, Table 3, Table 4, and Table 5 were kneaded to prepare an unvulcanized rubber sheet having a thickness of 2 mm. Of these various rubber sheets, six types of Examples 1 to 5 and Comparative Example 1 were used for tire size 13
The entire surface of the 5SR12 green tire was divided into 6 equal parts and attached.
The remaining rubber sheets were also divided into 6 equal parts and attached to the entire surface of a raw tire of the same size. Tires of the same size were continuously vulcanized for two weeks, and these raw tires were put in a mold whose surface was stained black, and were vulcanized for 15 minutes, and the tires were taken out as usual. The mold cleaning degree at that time was visually evaluated. The evaluation was made on a scale of 10 with 1 being the case of not being washed at all and 10 being the case of being completely washed. The results are also shown in Table 1, Table 2, Table 3, Table 4, and Table 5. The content of the compound of the conventional example is described in Polymer Tomo, Vol. 11, p. 693 to p. 695 (1983), and 100 parts by weight of EPDM and silica.
20 parts by weight, 2-amino-2-methyl-1-propanol 30 parts by weight, titanium oxide 10 parts by weight, stearic acid 1 part by weight, zinc white 5 parts by weight, dicumyl peroxide 9 parts by weight and sulfur 0.3 parts by weight Is. Comparative Example 1 has a silica content of less than 30 parts by weight Comparative Example 2 has a silica content of more than 90 parts by weight Comparative Example 3 has an amino alcohol content of less than 2 parts by weight Comparative Example 4 has a glycols content of 5 parts by weight Less than 10 parts by weight Comparative Example 5 shows amino alcohol content over 30 parts by weight Comparative Example 6 shows glycols content over 50 parts by weight. From Table 1, the mold cleaning rubber composition of the present invention shown in Examples is remarkably excellent in cleaning effect.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

[0031]

[Table 4]

[0032]

[Table 5]

[0033]

[Effects of the Invention] Conventionally, there has been no mold cleaning rubber composition excellent in cleaning effect. Therefore, molds for tires and the like are washed by removing the mold and performing shot blasting with glass beads or plastic beads. Therefore, a lot of man-hours have been spent, but by using the mold cleaning rubber composition of the present invention, it has become possible to significantly reduce the man-hours and remarkably improve the damage on the mold surface.

Claims (11)

[Claims] 1. Amino alcohol 2 to 30 relative to 100 parts by weight of rubber made of natural rubber and / or synthetic rubber.
Parts by weight, glycols 5 to 50 parts by weight, and adsorbent 3
A mold cleaning rubber composition comprising 0 to 90 parts by weight. 2. The amino alcohol is monoethanolamine, diethanolamine, triethanolamine, N
-Methylethanolamine, N, N-dimethylethanolamine, N, N-dibutylethanolamine, N, N
The gold according to claim 1, which is at least one selected from the group consisting of -diethylethanolamine, N-methyl-N, N-diethanolamine, 2-amino-2-methylpropanol, 3-aminopropanol and 2-aminopropanol. Mold cleaning rubber composition. 3. The mold cleaning rubber composition according to claim 1, wherein the glycol is at least one selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol and dipropylene glycol. 4. The mold according to claim 1, wherein the amino alcohol is at least one selected from the group consisting of monoethanolamine, diethanolamine, 2-amino-2-methylpropanol, 3-aminopropanol and 2-aminopropanol. Cleaning rubber composition. 5. The mold cleaning rubber composition according to claim 1, wherein the glycols are diethylene glycol and / or dipropylene glycol. 6. The rubber 10 is used in the amount of amino alcohol compounded.
The mold cleaning rubber composition according to claim 1, which is 5 to 20 parts by weight with respect to 0 parts by weight. 7. The mold cleaning rubber composition according to claim 1, wherein the blending amount of glycols is 10 to 30 parts by weight with respect to 100 parts by weight of rubber. 8. The adsorbent is silica, activated alumina, activated carbon, magnesium oxide, titanium oxide, calcium carbonate,
The mold cleaning rubber composition according to claim 1, which is at least one selected from the group consisting of bentonite and diatomaceous earth. 9. The mold cleaning rubber composition according to claim 1, wherein the adsorbent is silica. 10. The mold cleaning rubber composition according to claim 1, wherein the amount of the adsorbent compounded is 40 to 70 parts by weight. 11. Water is 2 parts by weight per 100 parts by weight of rubber.
The mold cleaning rubber composition according to claim 1, wherein the rubber composition is blended in an amount of about 20 parts by weight.