JPH05278042A - Rubber composition for cleaning mold and cleaning method therewith - Google Patents

Abstract

PURPOSE:To improve a cleaning rubber in flowability to charge the cleaning rubber into all parts of a mold having a complicated shape to enhance a cleaning effect by compounding amino alcohol, glycols, an adsorbent, and a specific organic silane with the rubber, respectively, in a specific ratio. CONSTITUTION:A mold cleaning rubber composition is prepared by compounding 2-30 pts.wt. of amino alcohol, 5-50 pts.wt. of glycols, 30-90 pts.wt. of an adsorbent, and 0.1-10 pts.wt. of an organic silane shown by a general formula Z-Alk- Sn-Alk-Z per 100 pts.wt. of a rubber made of a natural rubber and/or a synthetic rubber. A cleaning rubber article with the sheet-form cleaning rubber composition attached is inserted into a mold and heated for adsorbing a contaminant to the cleaning rubber article. After that, the cleaning rubber article is taken out of the mold. In this manner, the contaminant is removed from the surface of the mold. At this time, in the general formula, Z is a group as shown by another formula, where R<1>-R<3> are alkoxy group, Alk is hydrocarbon radical, and (fl) is an integer of 2-6.

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 and a mold cleaning method using the same, and more particularly to cleaning a rubber mold whose surface is contaminated by repeated vulcanization. TECHNICAL FIELD The present invention relates to a mold cleaning rubber composition and a cleaning method.

[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 phosphate or a cyclopentadiene derivative carboxylic acid salt to an outer surface liquid, and a compound having a silicon and an isocyanate group in the molecule described in JP-A-62-113518. Surface treatment of the mold with a rubber composition, or cyclized polybutadiene (JP-A-54-63144), organic phosphoric acid ester salt (JP-B-57-53812),
Mercaptobenzo-1,3-diazole salt (JP-A-54
No. 107943), a metal salt of a carboxylic acid of a cyclopentadiene derivative (JP-A-54-126251),
An attempt to improve mold contamination by adding 2-mercaptobenzimidazole or its zinc salt (Japanese Patent Publication No. 61-20585 or specific silica (hydrous silicic acid, Japanese Patent Laid-Open No. 63-238143)) is proposed. Has been done.

However, although these methods can delay the pollution, they cannot completely prevent the pollution. Therefore, periodical mold cleaning such as shot blasting with glass beads, acid or alkali cleaning is performed, but these mold cleaning damages the mold and accelerates 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. There was a flaw.

Further, as a method of cleaning without removing the mold from the vulcanizer, a method of using a rubber composition containing an 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 solution 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 and cleaned by a usual method (JP-A-58-18).
No. 0600), and many other mold-cleaning rubber compositions are generally commercially available. However, although they have some effects, they are still not sufficient, and these cleaning rubber compositions are also known. Most 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 in the working environment. It was a problem.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the inventors of the present invention have previously disclosed in Japanese Patent Application No. 3-349749 a metal mold containing an amino alcohol, a glycol and an adsorbent. A cleaning rubber composition was proposed, and the mold was scratched, corroded, or working environment problems were solved. However, since this mold-cleaning rubber composition contains amino alcohol, the vulcanization rate is extremely high. Therefore, when cleaning a mold having a complicated shape, the cleaning rubber composition is applied to every corner of the mold. In some cases, it was difficult to fill the product and the contaminants could not be completely removed. The object of the present invention is to improve the fluidity of the cleaning rubber while using the above-mentioned compounding agent so that the cleaning rubber can be filled into every corner of a mold having a complicated shape, thereby further exerting the cleaning effect. A rubber composition and a cleaning method using the same.

[0007]

Means for Solving the Problems As a result of the above-mentioned problems, the present inventors have conducted extensive studies to provide a further excellent mold-cleaning rubber composition that can be used for cleaning molds of any shape. By further adding a specific organic silane to a rubber composition containing an amino alcohol, a glycol and an adsorbent, the fluidity of the cleaning rubber is improved,
The present invention has been completed by finding that a cleaning rubber is filled into every corner of a mold having a complicated shape and a remarkable cleaning effect is exhibited.

That is, the present invention relates to 2 to 30 parts by weight of amino alcohol, 5 to 50 parts by weight of glycols, 30 to 90 parts by weight of adsorbent, and 100 to 100 parts by weight of a rubber composed of natural rubber and / or synthetic rubber, and a general formula. : Z-Alk
-Sn-Alk-Z (wherein Z is a group

[Chemical 2] Wherein R ¹ , R ² and R ³ are alkoxy groups having 1 to 4 carbon atoms, and all symbols R ¹ and R
² , R ³ may be the same or different and Al
k represents a hydrocarbon having 1 to 6 carbon atoms, and n is a number of 2 to 6}.
It is a mold cleaning rubber composition containing 10 to 10 parts by weight.

The present invention also provides a method for cleaning a contaminated mold by repeatedly vulcanizing unvulcanized rubber, wherein the mold-cleaning rubber composition is provided on the surface of the unvulcanized rubber article facing the mold. A cleaning rubber article made by pasting a sheet-shaped object is inserted into a mold, heated to adsorb contaminants to the cleaning rubber article, and then the cleaning rubber article is taken out from the mold. Thus, the method for cleaning a rubber mold is characterized in that contaminants are removed from the surface of the mold.

Also, water is added to 2 parts by weight per 100 parts by weight of rubber.
The method for cleaning a rubber mold as described above, wherein the cleaning rubber composition containing about 20 parts by weight is attached to an unvulcanized rubber article.

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 mentioned, but the 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, These may be used alone or in combination of two or more.

The compounding amount is 100 parts by weight of rubber,
It is 2 to 30 parts by weight, preferably 5 to 20 parts by weight. If the blending amount is less than 2 parts by weight, the mold cleaning effect is not sufficient,
When it exceeds 30 parts by weight, the breaking strength of the rubber composition is lowered, and when the rubber composition is taken out after cleaning the mold, the cleaning rubber composition is cut off on the way and remains in the mold, which is also cleaned. Not only is the effect worsened, but an excess of 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 exhibited, 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 strip contaminants from the surface of the mold. As the adsorbent, silica, activated alumina, activated carbon, magnesium oxide, titanium oxide, magnesium carbonate is used. , Calcium carbonate, bentonite, diatomaceous earth, etc. are used, but when removing the rubber composition 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 glass. The compounding amount is 30 to 90 parts by weight, preferably 40 to 70 parts by weight, based on 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, it is represented by the general formula Z-Alk-Sn-Alk-Z, where Z is a group represented by Chemical formula 2, wherein R ¹ , R ² and R ^{3 are} Is an alkoxy group having 1 to 4 carbon atoms, and all symbols R ¹ , R ² , R ³ may be the same or different, and Alk has 1 to 6 carbon atoms. Represents a straight or branched chain hydrocarbon having n, and n is an organic silane having a number of 2 to 6. For example, it is made by the method described in Japanese Patent Publication No. 51-28623, and as a specific example, Degus.
Bis (3 sold under the trade name of Si69 from sa company)
-Triethoxysilylpropyl) -tetrasulfane.

Here, the organic silane has the function of improving the fluidity of the cleaning rubber and filling the cleaning rubber in every corner of the mold having a complicated shape to enhance the cleaning effect.
The amount of the organic silane compounded was 100 parts by weight of rubber.
1 to 10 parts by weight, preferably 0.5 to 5 parts by weight. If the blending amount is less than 0.1 parts by weight, the effect of addition is not obtained, and if it exceeds 10 parts by weight, the effect of increasing the amount is no longer obtained, which is not preferable.

In the rubber composition of the present invention, water can be blended in order to further enhance the cleaning effect. Water has an azeotropic effect with glycols such as polyethylene glycol, and has an effect that it is easily vaporized and penetrates into a narrow portion. 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 and vulcanization accelerators such as sulfur, and aging are used. Inhibitors and the like can be added as needed.

The rubber composition of the present invention can be suitably used for cleaning molds for vulcanizing all rubber products including tires. Further, as a method of cleaning, a cleaning rubber composition may be prepared in a shape similar to that of an unvulcanized rubber product and may be carried out by an ordinary vulcanization operation. It is more preferable to make a sheet of about 1 to 5 mm and attach it to the surface of an unvulcanized rubber product to perform a vulcanization operation. This is because excess amino alcohol and glycols remain on the mold surface after washing. Since it does not exist, the problem of warping and contaminating the mold is eliminated, which is preferable.

[0021]

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 were kneaded, and these various rubber compositions were heated at 170 ° C. for 10 minutes under a pressure of 40 psi using a Garlock Flow Index tester, and then the fluidity of the rubber was changed to rubber. Was evaluated by measuring the length of the shed.

Next, these various rubber compositions were applied to a thickness of 2 mm.
The unvulcanized rubber sheet of Example 5 was used, and among these various rubber sheets, 5 types of Examples 1 to 4 and Comparative Example 1 were attached to the entire surface of a raw tire having a tire size of 135SR12 into 5 equal parts. Regarding the remaining rubber sheets, the entire surface of a raw tire of the same size was divided into 5 parts and attached. These raw tires were put into a mold whose surface was stained black by continuously vulcanizing tires of the same size for 2 weeks.
It was vulcanized for 5 minutes and the tire was taken out as usual. For these tires, in order to evaluate the cleanliness of the vent hole part of the tread part, vent pieces were randomly selected from each 50
After this main sampling, contaminants adhering to the surface were scraped off with a knife, and the weight was measured. The case where the weight was the highest was set to 10 as the cleansing degree, and the others were expressed by the index.
Therefore, the larger the value, the better. The results are shown in Table 1.

[0023]

[Table 1]

As is apparent from Table 1, the mold cleaning rubber composition of the present invention shown in the examples has a remarkable cleaning effect because the cleaning rubber flows to the details of the mold. In Comparative Example 2 in which 12 parts by weight of the organic silane was used in excess of 10 parts by weight, the fluidity of the rubber was slightly increased, but the mold cleaning effect was lower than that in the case of 3 parts by weight, which was economical. Not good for

[0025]

The present inventors have previously proposed (Japanese Patent Application No. 3-
349749) A mold cleaning rubber composition in which rubber is mixed with amino alcohol, glycols, and an adsorbent has solved the problem of damaging or corroding the mold or working environment. Therefore, the vulcanization rate is extremely fast, and when cleaning a mold having a complicated shape, it is difficult to fill the cleaning rubber composition to every corner of the mold, and there are cases where contaminants cannot be completely cleaned. In the present invention, by blending a specific organic silane, the fluidity of the rubber can be increased, so that the cleaning rubber composition is filled in every corner of the mold, and the cleaning effect is extremely remarkable. In the mold cleaning of tires, etc., the mold was removed, and cleaning was performed by shot blasting with glass beads or plastic beads, so a large number of man-hours were spent, but the present invention significantly reduces the man-hours and damages the mold surface. It was remarkably improved.

[Procedure amendment]

[Submission date] November 6, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Chemical 1] Wherein R ¹ , R ² and R ³ are alkoxy groups having 1 to 4 carbon atoms, and all symbols R ¹ and R
² , R ³ may be the same or different and Al
k represents a hydrocarbon having 1 to 6 carbon atoms, and n is a number of 2 to 6}. A mold cleaning rubber composition comprising 0.1 to 10 parts by weight of an organic silane.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 13

[Correction method] Change

[Correction content]

[Chemical 2] Wherein R ¹ , R ² and R ³ are alkoxy groups having 1 to 4 carbon atoms, and all symbols R ¹ and R
² , R ³ may be the same or different and Al
k represents a hydrocarbon having 1 to 6 carbon atoms, and n is a number of 2 to 6}.
After a sheet-shaped cleaning rubber composition containing 10 parts by weight of the rubber composition is attached, the cleaning rubber article is inserted into a mold and heated to adsorb contaminants to the cleaning rubber article. ,
A method for cleaning a rubber mold, wherein contaminants are removed from the surface of the mold by removing the cleaning rubber article from the mold.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

That is, the present invention relates to 2 to 30 parts by weight of amino alcohol, 5 to 50 parts by weight of glycols, 30 to 90 parts by weight of adsorbent, and 100 to 100 parts by weight of a rubber composed of natural rubber and / or synthetic rubber, and a general formula. : Z-Alk
-Sn-Alk-Z (wherein Z is a group

[Chemical 3] Wherein R ¹ , R ² and R ³ are alkoxy groups having 1 to 4 carbon atoms, and all symbols R ¹ and R
² , R ³ may be the same or different and Al
k represents a hydrocarbon having 1 to 6 carbon atoms, and n is a number of 2 to 6}.
It is a mold cleaning rubber composition containing 10 to 10 parts by weight.

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Claims (15)

[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, adsorbent 30 to 9
0 parts by weight and general formula: Z-Alk-Sn-Alk-Z
{Wherein Z is a group Wherein R ¹ , R ² and R ³ are alkoxy groups having 1 to 4 carbon atoms, and all symbols R ¹ and R
² , R ³ may be the same or different and Al
k represents a hydrocarbon having 1 to 6 carbon atoms, and n is a number of 2 to 6}. A mold cleaning rubber composition comprising 0.1 to 10 parts by weight of an organic silane. 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 2, 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 glycol is diethylene glycol,
And / or dipropylene glycol. The mold cleaning rubber composition according to claim 3. 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 mold cleaning rubber composition according to claim 1, wherein the adsorbent is silica, activated alumina, activated carbon, magnesium oxide, titanium oxide, magnesium carbonate, calcium carbonate, bentonite, or diatomaceous earth. 9. The mold cleaning rubber composition according to claim 8, 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 based on 100 parts by weight of the rubber. 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 contained in an amount of about 20 parts by weight. 12. The mold cleaning rubber composition according to claim 1, wherein the organosilane is bis (3-triethoxysilylpropyl) -tetrasulfane. 13. A method for cleaning a contaminated mold by repeatedly vulcanizing an unvulcanized rubber article, comprising a natural rubber and / or a surface of the unvulcanized rubber article facing the mold.
Alternatively, 2 to 30 parts by weight of amino alcohol, 5 to 50 parts by weight of glycols, 30 to 90 parts by weight of adsorbent, and 100 to 100 parts by weight of a synthetic rubber, and a general formula: Z-Al
k-Sn-Alk-Z (wherein Z is a group ## STR1 ## wherein R ¹ , R ² and R ³ are alkoxy groups having 1 to 4 carbon atoms and all symbols are R ¹ , R ² and R ³ may be the same or different, Alk represents a hydrocarbon having 1 to 6 carbon atoms, and n is a number of 2 to 6}. A cleaning rubber article prepared by adhering a sheet-shaped cleaning rubber composition containing 0.1 to 10 parts by weight of organic silane is inserted into a mold and heated to clean contaminants. A method for cleaning a rubber mold, wherein the cleaning rubber article is removed from the mold after being adsorbed on the mold, thereby removing contaminants from the surface of the mold. 14. Water is added in an amount of 2 to 100 parts by weight of rubber.
The method for cleaning a rubber mold according to claim 13, wherein the cleaning rubber composition containing about 20 parts by weight is attached to an unvulcanized rubber article. 15. The organosilane is bis (3-triethoxysilylpropyl) -tetrasulfane.
The method for cleaning a rubber mold described.