JP3628115B2 - Mold cleaning rubber composition and mold cleaning method - Google Patents

Description

【００２６】
〔上記表１の考察〕
本発明範囲となる実施例１〜３は、本発明範囲外なる比較例１〜３に較べて、洗浄効果と同等か又は優れ、また、洗浄作業性も良好であり、しかも、その洗浄効果は固体ゴムに比べ１年以上経過しても優れていることが判明した。
これに対して、比較例１は、従来の固体状の金型洗浄ゴムであるので、洗浄作業性に問題があり、また、洗浄効果の持続も１カ月しかないものであった。
比較例２は、溶媒である水が多いので、エマルジョン粘度が低くなりすぎ、液ダレするため作業性が低下するばかりか、ゴム強度が低くなる傾向にあり、又、加硫中に多量の蒸気を発生した。
比較例３は、アミノアルコール類が少ないので、目的の洗浄効果が得られなかった。
【００２７】
【発明の効果】
本発明によれば、エマルジョン化した金型洗浄ゴム組成物を使用することにより、作業性の効率化と長期保存性を有する金型洗浄ゴム組成物及び金型洗浄方法が提供される。[0001]
[Industrial application fields]
The present invention relates to cleaning of a rubber mold, and more particularly to a mold cleaning rubber composition and a mold cleaning method used for cleaning a mold whose surface is contaminated by repeated vulcanization.
[0002]
[Prior art]
In the rubber molding industry, vulcanization mold contamination has been known for a long time, and mold contamination is promoted with the frequency of use in the vulcanization process, and the quality, appearance, dimensional accuracy, etc. of rubber molded products There are problems such as giving serious defects to the product, shortening the mold releasability and shortening the life of the mold.
[0003]
Therefore, many studies have been made so far as countermeasures against mold contamination. As a conventional mold cleaning method, for example,
(1) Shot blasting method in which glass beads or plastic beads are placed on the mold to physically remove dirt,
(2) Mold cleaning method with acid or alkali,
(3) A mold cleaning method for cleaning a mold by bonding dirt from a metal surface to a rubber surface using a mold cleaning rubber,
(4) Mold cleaning method for cleaning molds by plasma treatment, etc.
Etc. are known.
Mold cleaning by the shot blasting method of (1) above, cleaning with acid or alkali of (2) above, plasma processing of (4) above, etc., damages the mold and makes the subsequent contamination rate rapid, In addition to corroding the mold, it is necessary to remove the mold from the vulcanizer for cleaning. Especially in the case of large rubber products, the man-hours cannot be ignored and the productivity is reduced. there were.
[0004]
Among the above (1) to (4), the use of the mold cleaning rubber of the above (3) is very advantageous in terms of production cost because it can be cleaned without removing the mold from the vulcanizer. It is a simple method.
Examples of the mold cleaning rubber include a mold cleaning rubber composition (Japanese Patent Laid-Open No. 58-122942) in which amino alcohol is blended with Japanese Patent Laid-Open No. 58-122942, and amino alcohol, glycols, and adsorption. Mold cleaning rubber composition (JP-A-5-154850) obtained by blending an agent, and further, the cleaning rubber is filled to every corner of a mold having a complicated shape, and the cleaning effect is further exhibited. As an example, a mold cleaning rubber composition (Japanese Patent Laid-Open No. 6-128416) formed by blending amino alcohol, glycols, an adsorbent and an organic peroxide is known. The amino alcohol blended in these mold cleaning rubber compositions exhibits an excellent mold cleaning effect as a cleaning component.
[0005]
The use of the mold cleaning rubber composition disclosed in these publications can be achieved by vulcanizing the rubber composition itself so as to come into contact with the cleaning site of the mold or by sticking the rubber composition to the surface of the product rubber. This is done by vulcanizing the product.
By the way, the mold cleaning rubber composition has a higher unit price than a general rubber composition, and also generates ammonia odor due to evaporation of amino alcohol during vulcanization, so that the minimum amount necessary for cleaning is used. In general, the above-described mold cleaning rubber composition is used by vulcanizing a product rubber surface with the rubber composition attached thereto.
[0006]
However, in this method of use, (1) it is necessary to remold the mold cleaning rubber composition into a sheet having a desired thickness, (2) raw rubber is required, and (3) the mold cleaning rubber composition is used. (4) The mold cleaning rubber composition must be sealed for long-term storage because the cleaning component is volatile, but it is difficult to seal these rubber sheets. There are problems in work and long-term storage.
[0007]
[Problems to be solved by the invention]
An object of the present invention is to solve the problems in the conventional mold cleaning rubber composition described above, and provide a mold cleaning rubber composition and a mold cleaning method having improved workability and long-term storage. It is to be.
[0008]
[Means for Solving the Problems]
As a result of earnest research to solve the above problems, the present inventor has added a specific component that does not impair the cleaning function to the mold cleaning rubber composition to obtain a specific state, thereby achieving the above target mold. The present inventors have succeeded in obtaining a cleaning rubber composition and a mold cleaning method, and have completed the present invention.
[0009]
That is, the mold cleaning rubber composition of the present invention has a reinforcing agent of 30 to 100 parts by weight, an amino alcohol of 2 to 30 parts by weight with respect to 100 parts by weight of a refined rubber made of natural rubber and / or synthetic rubber, It is characterized by being made into an emulsion comprising 30 to 100 parts by weight of a solvent and 1 to 10 parts by weight of a surfactant.
Further, the mold cleaning method of the present invention is a method for cleaning a contaminated mold by repeatedly vulcanizing an unvulcanized rubber article, and the surface of the unvulcanized rubber article facing the mold is After the mold cleaning rubber composition is inserted into the mold and heated to adsorb contaminants on the cleaning rubber article, the contaminant is removed from the mold surface by removing the cleaning rubber article from the mold. It is characterized by.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
In the mold cleaning rubber composition of the present invention, as the rubber to be used, for example, a single rubber or a blend rubber arbitrarily selected from natural rubber and various synthetic rubbers can be used. Specific examples of the synthetic rubber include synthetic polyisoprene rubber. Styrene-butadiene copolymer rubber, polybutadiene rubber, butyl rubber, halogenated butyl rubber, ethylene propylene terpolymer, and the like, but are not limited thereto.
In the present invention, refined rubber having an average particle size of 0.04 mm or less is used.
When the average particle size of the fine rubber exceeds 0.04 mm, the rubber settles out when stored for a long period of time, and a stirring operation is required at the time of use.
[0011]
The reinforcing agent used in the mold cleaning rubber composition of the present invention is used to remove contaminants from the mold surface. Examples of the reinforcing agent include carbon black, silica, activated alumina, activated carbon, and titanium oxide. At least one selected from the group consisting of magnesium carbonate, calcium carbonate, bentonite and diatomaceous earth can be used.
In addition, when cleaning a mold having a complicated shape, when the rubber composition is taken out after cleaning the mold, the rubber composition may be cut off halfway and remain in the mold. Carbon black is used as the reinforcing agent.
The compounding amount of the reinforcing agent is 30 to 100 parts by weight, preferably 50 to 80 parts by weight, based on 100 parts by weight of the fine rubber. When the compounding amount of the reinforcing agent is less than 30 parts by weight, the fracture strength of the rubber composition is low and the contaminants cannot be completely removed. When the amount exceeds 100 parts by weight, the viscosity of the rubber composition becomes too high. Thus, the rubber does not flow to the details of the mold during cleaning, and as a result, a portion that is not cleaned remains, which is not preferable.
[0012]
The amino alcohol used in the mold cleaning rubber composition of the present invention exhibits an excellent mold cleaning effect as a cleaning component. Examples of the amino alcohol include monoethanolamine, diethanolamine, and 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 can be used, and monoethanolamine, diethanolamine, 2-amino-2-methylpropanol, 3-aminopropanol and 2-aminopropanol are preferable. These may be used alone or in combination of two or more.
The compounding amount of amino alcohol is 2 to 30 parts by weight, preferably 10 to 20 parts by weight, with respect to 100 parts by weight of the fine rubber. If the blending amount is less than 2 parts by weight, the mold cleaning effect 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 removed when the rubber composition is taken out after cleaning the mold. Objects are cut off in the middle and remain in the mold, which not only deteriorates the cleaning effect, but also excessive amino alcohol remains on the mold surface. It becomes.
[0013]
The solvent used in the mold cleaning rubber composition of the present invention is used to effectively emulsify and further improve the cleaning effect. Examples of the solvent include water (purified water). used.
The compounding amount of the solvent is 30 to 100 parts by weight, preferably 40 to 60 parts by weight with respect to 100 parts by weight of the fine rubber. If the amount of the solvent is less than 30 parts by weight, phase inversion does not occur and it is difficult to emulsify. If it exceeds 100 parts by weight, the emulsion viscosity becomes too low and the workability is lowered due to dripping. The strength tends to be low, and a large amount of steam is generated during vulcanization, which is not preferable.
[0014]
The surfactant used in the mold cleaning rubber composition of the present invention is used for effective emulsification, and does not impair the function of essential ingredients such as amino alcohols. Is used.
Surfactants that can be used include, for example, cationic surfactants such as aliphatic amine salts and ammonium oleate, anionic surfactants such as carboxylates, sulfonates, sulfate esters, and phosphate esters, and imidazoles. Amphoteric surfactants such as nitrobetaine, nonionic surfactants such as polyoxyethylene alkyl ether, fluorine-based surfactants such as fluoroalkylcarboxylic acid, etc., preferably cationic surfactants such as ammon oleate These may be used alone or in combination of two or more.
The compounding amount of the surfactant is 1 to 10 parts by weight, preferably 2 to 5 parts by weight with respect to 100 parts by weight of the fine rubber. If the amount of the surfactant is less than 1 part by weight, the target emulsified mold cleaning rubber composition cannot be obtained, and if it exceeds 10 parts by weight, the rubber strength is undesirably lowered.
[0015]
In the mold cleaning rubber composition of the present invention, glycols and organic acids can be blended as necessary in order to further increase the cleaning effect.
As the glycols, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol and the like can be used, preferably diethylene glycol and dipropylene glycol. These may be used alone or in combination of two or more. I do not care. The blending amount of the glycols is 0 to 30 parts by weight, preferably 20 to 30 parts by weight with respect to 100 parts by weight of the fine rubber.
Further, as the organic acid, for example, tartaric acid, citric acid, malic acid, benzoic acid, stearic acid, lactic acid and the like can be used, preferably tartaric acid and citric acid, and these are used alone or in combination of two or more. It doesn't matter. The compounding amount of the organic acid is 0 to 20 parts by weight, preferably 0 to 10 parts by weight with respect to 100 parts by weight of the fine rubber.
[0016]
Furthermore, in the mold cleaning rubber composition of the present invention, fillers commonly used in the rubber industry, softeners such as aroma oil and naphthenic oil, vulcanizing agents such as sulfur, vulcanization accelerators, and anti-aging agents A rubber compounding agent such as can be blended as necessary.
[0017]
The mold cleaning rubber composition of the present invention includes the above-mentioned refined rubber, reinforcing agent, amino alcohol, solvent, surfactant, glycols blended as necessary, organic acid, and the above-mentioned rubber compounding agent. Can be emulsified by mixing and stirring with an ordinary mixing and stirring device, for example, a high-speed shear mixer. Preferably, it becomes easy to emulsify by high-speed shearing of 1000 times / minute or more under heating and pressure.
[0018]
The obtained emulsified mold cleaning rubber composition is suitably used for cleaning molds for vulcanizing all rubber products including tires. In addition, since it can be kept emulsified for more than a year by sealing in a container or the like, it can be stored and transported more easily than conventional solid mold cleaning rubber compositions, and is suitable for long-term storage. (This point will be further described in the embodiments described later).
[0019]
Further, the mold cleaning method of the present invention is a method for cleaning a contaminated mold by repeatedly vulcanizing an unvulcanized rubber article, and the surface of the unvulcanized rubber article facing the mold is Apply the mold cleaning rubber composition obtained in step 1 directly to the mold with a spray, nozzle, etc. or apply it to the surface of the raw rubber product, insert it into the mold, and heat to adsorb contaminants onto the cleaning rubber article. Then, the cleaning rubber article is removed from the mold to remove contaminants from the mold surface.
According to the mold cleaning method of the present invention, since the emulsified mold cleaning rubber composition can be directly applied to the mold by spraying, nozzles, etc., the conventional solid mold cleaning rubber composition was used. Compared to pasting work, there is almost no preparation work, the workability is extremely simple, and the mold cleaning rubber composition remaining after use can be easily sealed in a container etc. Become.
[0020]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited at all by these Examples.
[0021]
(Examples 1-3 and Comparative Examples 2-3)
An emulsified mold cleaning rubber composition was prepared by mixing and stirring with a high-speed shear mixer with the blending contents shown in Table 1 below.
(Comparative Example 1)
A rubber composition was kneaded with a Banbury mixer with the blending contents shown in Table 1 below to prepare a solid mold cleaning rubber composition.
Evaluation of the cleaning effect, cleaning workability, and sustainability of the various mold cleaning rubber compositions of Examples 1 to 3 and Comparative Examples 1 to 3 prepared above were evaluated by the following methods.
These results are shown in Table 1 below.
[0022]
(Evaluation of cleaning effect)
The cleaning effects of the various rubber compositions prepared above were evaluated by the following methods.
In the emulsified mold cleaning rubber compositions of Examples 1 to 3 and Comparative Examples 2 to 3, the emulsified mold cleaning rubber composition was applied to the entire surface of a green tire having a tire size of 135SR12 by spraying.
Further, in the solid mold cleaning rubber composition of Comparative Example 1, the unvulcanized rubber sheet having a thickness of 2 mm was used, and this rubber sheet was applied by dividing the entire surface of the raw tire of tire size 135SR12 into four equal parts. I attached.
These raw tires were vulcanized continuously for 2 weeks with tire size 135SR12, and then put into a mold whose surface was contaminated with black, and vulcanized for 15 minutes at a platen temperature of 165 ° C. The tire was removed and washed as usual.
The degree of cleaning at that time was visually evaluated according to the following evaluation criteria.
Evaluation criteria for cleaning effect ◎: Very good ○: Good △: Unevenness remains [0023]
(Cleaning workability)
The following evaluation criteria evaluated the possibility of emulsification and the presence or absence of dripping at the time of application.
Evaluation criteria for cleaning workability ○: No problem △: Difficult to work [0024]
(Duration of effect)
The emulsified rubber was allowed to stand for 1 month to 1 year in a sealed state, and the degree of cleaning effect was confirmed by the above-described evaluation method for cleaning effect.
[0025]
[Table 1]

[0026]
[Consideration of Table 1 above]
Examples 1 to 3, which are within the scope of the present invention, are equivalent to or superior to the cleaning effect as compared with Comparative Examples 1 to 3, which are outside the scope of the present invention, and the cleaning workability is good, and the cleaning effect is It was found that it was superior to solid rubber even after 1 year.
On the other hand, since Comparative Example 1 is a conventional solid mold cleaning rubber, there is a problem in cleaning workability, and the cleaning effect lasts only one month.
In Comparative Example 2, since the amount of water as a solvent is large, the emulsion viscosity becomes too low, so that the workability is lowered due to dripping, and the rubber strength tends to be low. Occurred.
Since the comparative example 3 had few amino alcohols, the target cleaning effect was not acquired.
[0027]
【The invention's effect】
According to the present invention, by using an emulsified mold cleaning rubber composition, a mold cleaning rubber composition and a mold cleaning method having improved workability and long-term storage are provided.

Claims (7)

30 to 100 parts by weight of a reinforcing agent, 2 to 30 parts by weight of an amino alcohol, 30 to 100 parts by weight of a solvent, and 1 to 1 of a surfactant with respect to 100 parts by weight of a refined rubber composed of natural rubber and / or synthetic rubber. A mold cleaning rubber composition comprising an emulsion containing 10 parts by weight. The mold cleaning rubber composition according to claim 1, wherein the refined rubber has an average particle size of 0.04 mm or less. The mold cleaning rubber composition according to claim 1 or 2, wherein the reinforcing agent is at least one selected from the group consisting of carbon black, silica, activated alumina, activated carbon, titanium oxide, magnesium carbonate, calcium carbonate, bentonite, and diatomaceous earth. Stuff. The amino alcohols are monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, N, N-dimethylethanolamine, N, N-dibutylethanolamine, N, N-diethylethanolamine, N-methyl-N The mold cleaning according to any one of claims 1 to 3, which is at least one selected from the group consisting of N, diethanolamine, 2-amino-2-methylpropanol, 3-aminopropanol, and 2-aminopropanol. Rubber composition. The mold cleaning rubber composition according to any one of claims 1 to 4, wherein the solvent is water. 6. The surfactant according to claim 1, wherein the surfactant is at least one selected from the group consisting of a cationic surfactant, an anionic surfactant, an amphoteric surfactant, a nonionic surfactant, and a fluorosurfactant. The metal mold | die cleaning rubber composition as described in one. In a method of cleaning a mold contaminated by repeatedly vulcanizing an unvulcanized rubber article, the surface of the unvulcanized rubber article facing the mold is any one of claims 1 to 6. Insert the described mold cleaning rubber composition into the mold, heat to adsorb the contaminants to the cleaning rubber article, and then remove the cleaning rubber article from the mold to remove the contaminants from the mold surface. A mold cleaning method characterized by: