JP3179179B2 - Mold cleaning rubber composition and cleaning method - Google Patents

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 a method for cleaning a rubber mold whose surface is contaminated by repeated vulcanization. The present invention relates to a mold cleaning rubber composition and a cleaning method used.

[0002]

2. Description of the Related Art In the rubber molding and processing industry, contamination of a vulcanizing mold has been known for a long time. There are problems such as giving a serious defect to the product such as appearance and dimensional accuracy, releasing from the mold and shortening the life of the mold.

[0003] For this reason, many studies have been made as a countermeasure against mold contamination, and for example, Japanese Patent Publication No. 59-4498.
0, a method of adding an organic phosphate or a cyclopentadiene derivative carboxylate to an outer surface liquid, or a compound having a silicon and isocyanate group in a molecule described in JP-A-62-113518. Surface treatment of a metal mold, or cyclized polybutadiene (JP-A-54-63144), an organic phosphate salt (JP-B-57-53812),
Mercaptobenzo-1,3-diazole salt (JP-A-54
-107943), a metal salt of a carboxylic acid of a cyclopentadiene derivative (Japanese Patent Application Laid-Open No. 54-126251),
Attempts to improve mold contamination by blending 2-mercaptobenzimidazole or its zinc salt (Japanese Patent Publication No. 61-20585 or a specific silica (hydrous silicic acid, Japanese Patent Application Laid-Open No. 63-238143)) have been proposed. Have been.

[0004] However, these methods can delay the contamination, but cannot completely prevent the contamination. For this reason, regular mold cleaning such as shot blasting using glass beads, acid or alkali cleaning, etc. are performed.However, these mold cleanings damage the mold and increase the subsequent contamination rate, In addition to corroding the mold, the mold must be removed from the vulcanizer for cleaning, and especially in the case of large rubber products, the man-hours cannot be ignored and productivity is reduced. There were drawbacks.

Further, as a method of cleaning a mold without removing it from a vulcanizer, Japanese Patent Application Laid-Open No. 58-122942 discloses a method of using a rubber composition containing an amino alcohol as a cleaning rubber. A method in which a cleaning solution in which amino alcohol is dissolved in ethanol or the like is applied to a contaminated mold surface, and then the unvulcanized rubber composition is vulcanized and cleaned by an ordinary method (Japanese Patent Application Laid-Open No. 58-18 / 1983).
No. 0600), and many other mold cleaning rubber compositions are generally commercially available. However, although they have a certain degree of effect, they are still not sufficient, Most of them contain a large amount of amine-based chemicals that are easily decomposed, so that they smell ammonia even at room temperature, generate more amine after heating, and corrode the mold. It was a problem.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present inventors have previously disclosed in Japanese Patent Application No. 3-349949 a mold containing an amino alcohol, glycols and an adsorbent. A cleaning rubber composition was proposed to solve the problem of damaging or corroding a mold or working environment. However, since the mold cleaning rubber composition contains an amino alcohol, the vulcanization rate is extremely high, and therefore, when cleaning a mold having a complicated shape, the cleaning rubber composition reaches every corner of the mold. In some cases, the substance was difficult to fill, and contaminants could not be completely removed. An object of the present invention is to improve the flowability of a cleaning rubber while using the above-mentioned compounding agent, to fill the cleaning rubber into every corner of a mold having a complicated shape, and to further exert a cleaning effect. An object of the present invention is to provide a rubber composition and a cleaning method using the same.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted the above-mentioned problems, that is, the results of intensive studies to provide a more excellent mold cleaning rubber composition which can be used for cleaning molds of all shapes. By further blending a specific organic silane with a rubber composition containing an amino alcohol, a glycol and an adsorbent, the flowability of the cleaning rubber is improved,
The present inventors have found that the cleaning rubber is filled in every corner of a mold having a complicated shape and exert a remarkable cleaning effect, and thus the present invention has been completed.

That is, according to the present invention, 2 to 30 parts by weight of an amino alcohol, 5 to 50 parts by weight of a glycol, 30 to 90 parts by weight of an adsorbent, and 30 to 90 parts by weight of a general rubber are used for 100 parts by weight of a rubber composed of natural rubber and / or synthetic rubber. : Z-Alk
—Sn-Alk-Z ｛wherein Z is a group

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

The present invention also relates to a method for cleaning a contaminated mold by repeatedly vulcanizing an unvulcanized rubber, the method comprising the steps of: A cleaning rubber article created by attaching a sheet-like article to a product is inserted into a mold, heated to adsorb contaminants to the cleaning rubber article, and then the cleaning rubber article is taken out of the mold. This is a method for cleaning a rubber mold, wherein contaminants are removed from the mold surface.

Water is added to 100 parts by weight of rubber to
The method for cleaning a rubber mold as described above, wherein the cleaning rubber composition blended with 20 to 20 parts by weight is adhered to an unvulcanized rubber article.

In the rubber composition of the present invention, the rubber may be a single rubber or a blend rubber arbitrarily selected from natural rubber and various synthetic rubbers. Specific examples of the synthetic rubber include a synthetic polyisoprene rubber and a styrene-butadiene copolymer. Examples thereof include, but are not limited to, polymerized rubber, polybutadiene rubber, butyl rubber, halogenated butyl rubber, and ethylene propylene terpolymer.

In the rubber composition of the present invention, amino alcohols include monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, N, N-dimethylethanolamine, N, N-dibutylethanolamine, 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, 2-aminopropanol, These may be used alone or in combination of two or more.

The compounding amount is based on 100 parts by weight of rubber.
It is 2 to 30 parts by weight, preferably 5 to 20 parts by weight. If the amount is less than 2 parts by weight, the mold cleaning effect is not sufficient,
If the amount exceeds 30 parts by weight, the breaking strength of the rubber composition decreases, and when the rubber composition is taken out after cleaning the mold, the cleaning rubber composition is cut off in the middle and remains in the mold. Not only the effect deteriorates, 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, preferably diethylene glycol and dipropylene glycol, may be used alone or in combination of two or more. 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 amount is less than 5 parts by weight, the mold cleaning effect is not sufficient. If the amount 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 reduced, and the mold cleaning effect is also deteriorated. Not only
Excessive glycols remain on the mold surface, which is not preferable.

In the rubber composition of the present invention, an adsorbent is blended to remove contaminants from the mold surface. Examples of the adsorbent include silica, activated alumina, activated carbon, magnesium oxide, titanium oxide, and magnesium carbonate. , Calcium carbonate, bentonite, diatomaceous earth, etc. are used, but when the rubber composition is taken out after washing the mold, in the case of a mold having a complicated shape, the rubber composition is cut in the middle, Therefore, silica having a reinforcing property is preferably used. 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 amount is less than 30 parts by weight, the breaking strength of the rubber composition is low, and contaminants cannot be completely removed. If the amount exceeds 90 parts by weight, the viscosity of the rubber composition becomes too high, and At this time, the rubber does not flow into the details of the mold, and as a result, a part that is not cleaned 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, wherein Z is a group, wherein R ¹ , R ² , R ³ 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. Is a straight-chain or branched-chain hydrocarbon, and n is an organic silane having a number of 2 to 6. For example, it is made by the method described in JP-B-51-28623, and as a specific example, Degus
A screw (3) commercially available from Sa Corporation under the trade name of Si69
-Triethoxysilylpropyl) -tetrasulfane.

Here, the organic silane has a function of improving the flowability of the cleaning rubber, filling the cleaning rubber into every corner of a mold having a complicated shape, and improving the cleaning effect.
The amount of the organic silane is 0.1 to 100 parts by weight of the rubber.
It is 1 to 10 parts by weight, preferably 0.5 to 5 parts by weight. If the amount is less than 0.1 part by weight, the effect of addition is not obtained. If the amount 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 for further improving the cleaning effect. Water has an azeotropic action with glycols such as polyethylene glycol, and has an effect that it is easily vaporized and penetrates into a thin portion. The compounding amount is 2 to 10 parts by weight. If the amount is less than 2 parts by weight, there is no effect of addition, and if it exceeds 20 parts by weight, not only the effect of increasing the amount is lost but also the kneading workability of the rubber composition deteriorates.

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

The rubber composition of the present invention can be suitably used for cleaning a mold for vulcanizing any rubber product such as a tire. As a washing method, a cleaning rubber composition may be prepared in the same shape as that of an unvulcanized rubber product, and may be carried out by a normal vulcanization operation. It is more preferable to carry out the vulcanization operation by sticking to an unvulcanized rubber product surface in the form of a sheet of about 1 to 5 mm, and it is preferable that excess amino alcohol and glycols remain on the mold surface after washing. This is preferable because there is no problem that the mold is contaminated by warpage.

[0021]

EXAMPLES The present invention will be described more specifically 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. Was evaluated by measuring the length of the run.

Next, these various rubber compositions were applied to a thickness of 2 mm.
The unvulcanized rubber sheets of Examples 1 to 4 and Comparative Example 1 among these various rubber sheets were adhered by dividing the entire surface of a raw tire having a tire size of 135SR12 into five equal parts. For the remaining rubber sheet, the whole surface of a green tire of the same size was affixed in five equal parts. By continuously vulcanizing the same size tires for two weeks, the raw tires are put into a black mold whose surface is contaminated with black.
After vulcanization for 5 minutes, the tire was removed as usual. In order to evaluate the degree of cleaning of the vent hole portion of the tread portion for each of these tires, the vent pieces were randomly placed 50 to 50 from each.
After the main sampling, contaminants adhering to the surface were scraped off with a knife, and the weight was measured. When the weight was the largest, the degree of cleaning was set to 10, and for the others, the weight was represented by an index.
Therefore, a larger value indicates better. The results are shown in Table 1.

[0023]

[Table 1]

As is clear from Table 1, the cleaning rubber composition of the present invention shown in the examples has a remarkably excellent cleaning effect because the cleaning rubber flows into the details of the die. In Comparative Example 2 in which the organic silane was used in an amount of more than 10 parts by weight and 12 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, and the economical efficiency was low. Not preferred.

[0025]

The present inventors have previously proposed (Japanese Patent Application No. Hei.
No. 349749) A mold cleaning rubber composition containing a rubber and an amino alcohol, a glycol and an adsorbent solves the problem of damaging or corroding the mold or working environment. Therefore, when the vulcanization rate is extremely fast, when cleaning a mold having a complicated shape, it is difficult to fill the cleaning rubber composition to every corner of the mold, and contaminants may not be completely cleaned. According to the present invention, by mixing 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 cleaning molds for tires, etc., the mold was removed and shot blasting with glass beads or plastic beads was performed, so a lot of man-hours were spent.However, the present invention greatly reduces man-hours and damages the mold surface. It was significantly improved.

────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ identification code FI C11D 7/60 C23G 5/00 C23G 5/00 C08K 5/54 // B29K 21:00 (58) Field surveyed (Int.Cl. . ^7, DB name) B29C 33/72 C08K 3/00 - 13/08 C08L 1/00 - 101/16

Claims (15)

(57) [Claims] 1. An amino alcohol of 2 to 30 parts by weight per 100 parts by weight of a rubber made of natural rubber and / or synthetic rubber.
Parts by weight, 5 to 50 parts by weight of glycols, 30 to 9 adsorbents
0 parts by weight and a general formula: Z-Alk-Sn-Alk-Z
ＺIn the formula, Z is a group. Wherein R ¹ , R ² , R ³ are alkoxy groups having 1 to 4 carbon atoms, and all symbols R ¹ , R
² and R ³ may be the same or different;
k is a hydrocarbon having 1 to 6 carbon atoms, and n is a number of 2 to 6; 2. The amino alcohol is monoethanolamine, diethanolamine, triethanolamine, N
-Methylethanolamine, N, N-dimethylethanolamine, N, N-dibutylethanolamine, N, N
2. 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 glycols are diethylene glycol,
4. The mold cleaning rubber composition according to claim 3, wherein the composition is a dipropylene glycol. 6. The method according to claim 1, wherein the amount of the amino alcohol is 10
The mold cleaning rubber composition according to claim 1, wherein the amount is 5 to 20 parts by weight based on 0 parts by weight. 7. The rubber composition according to claim 1, wherein the amount of the glycol is from 10 to 30 parts by weight based on 100 parts by weight of the 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 is 40 to 70 parts by weight based on 100 parts by weight of the rubber. 11. Water is added to 100 parts by weight of rubber,
The mold cleaning rubber composition according to claim 1, which is blended in an amount of from 20 to 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 mold contaminated by repeatedly vulcanizing an unvulcanized rubber article, wherein the surface of the unvulcanized rubber article facing the mold has natural rubber and / or natural rubber.
Alternatively, based on 100 parts by weight of a synthetic rubber, 2 to 30 parts by weight of an amino alcohol, 5 to 50 parts by weight of a glycol, 30 to 90 parts by weight of an adsorbent and a general formula: Z-Al
k-Sn-Alk-Z ｛wherein Z is a group Wherein R ¹ , R ² , R ³ are alkoxy groups having 1 to 4 carbon atoms, and all symbols R ¹ , R
² and R ³ may be the same or different;
k represents a hydrocarbon having 1 to 6 carbon atoms, and n represents a number of 2 to 6;
A cleaning rubber article prepared by attaching a sheet-like cleaning rubber composition containing 10 to 10 parts by weight is inserted into a mold and heated to adsorb contaminants to the cleaning rubber article. ,
A method for cleaning a rubber mold, comprising removing contaminants from the mold surface by removing the cleaning rubber article from the mold. 14. Water is added to 100 parts by weight of rubber,
14. The method for cleaning a rubber mold according to claim 13, wherein the cleaning rubber composition blended in an amount of about 20 parts by weight is adhered to an unvulcanized rubber article. 15. The organic silane is bis (3-triethoxysilylpropyl) -tetrasulfane.
A method for cleaning a rubber mold as described in the above.