JPS6138942B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to improving the kneading workability of the compounding step in the processing of chlorosulfonated polyethylene. Blending rubber and various compounding chemicals is a basic step in rubber processing, and is an important process in which both are uniformly dispersed in the dough by kneading. Depending on the type of rubber and the formulation for the rubber, it is often experienced that the dough (as defined in JIS 5215) strongly sticks to processing machines such as rolls and banburys during kneading operations. This is called kneading and adhesion. This makes the kneading operation extremely difficult, significantly reduces the efficiency of the processing process, impairs the dispersion of the ingredients in the kneaded dough, and ultimately deteriorates the physical properties after vulcanization. When kneading causes severe stickiness, kneading must be stopped, which is extremely inconvenient from a practical standpoint. The present invention provides a composition containing scorch-resistant, easily vulcanizable chlorosulfonated polyethylene, which does not cause the above-mentioned kneading adhesion during kneading work because it contains a kneading adhesion inhibitor. do. It is known that the degree of kneading adhesion during kneading of rubber compounds differs depending on the type of rubber, and chlorosulfonated polyethylene, along with chloroprene rubber, butyl rubber, epichlorohydrin rubber, acrylic rubber, etc. It is said to be one of the most sticky rubbers when kneaded. However, effective countermeasures for one type of rubber cannot be effective for other rubbers, and solutions have been developed for each case based on experience and the results of testing each polymer one by one. I came here. Even if the same drug is used, the effects are often completely different if the type of rubber is different. For example, AC polyethylene 1702 (Allied Chemical Co., Ltd.) is useful as a lubricant for chloroprene rubber, but cannot be expected to have an anti-kneading effect on chlorosulfonated polyethylene. In the rubber industry, the adhesion of raw rubber to each other is called mashing or lumping, but this is static adhesion that occurs when raw rubber, compounded rubber, and dough are piled up.There are methods to prevent this. As a method, powders such as talc, charcoal, clay, silica, magnesium carbonate, and calcium stearate are applied to the surface of the rubber fabric. Although this is also referred to as a lubricant, it does not help prevent the dynamic behavior of kneading stickiness that is intended by the present invention. In addition, there is adhesion called mold adhesion, which occurs during vulcanization when the dough is molded with a mold, and is caused by the contact between the dough and the mold as a result of the high temperature, heating, and compression during vulcanization. This is a phenomenon that occurs during this period, and is a different type of adhesion from the kneaded adhesion referred to in the present invention. Furthermore, oily components such as process oil are used to facilitate molding during rubber processing.
It has been recognized to be effective in improving extrusion processability when forming dough. However, it has been found that not only does this not solve the problem of kneading adhesion referred to in the present invention, but also that this oily component actually intensifies the kneading adhesion. There is no clear definition of kneading adhesion, and its causes and mechanisms are not well understood. It is difficult to predict the occurrence of this kneading adhesion, and it usually occurs suddenly during kneading. After kneading, stickiness occurs, wait for the dough to cool down and knead again to overcome the emergency situation. However, if stickiness is severe, be prepared for stickiness and, for example, when kneading with rolls, stop the machine after each roll pass. The dough has to be stretched and kneaded using a method, which requires an extremely long kneading time, resulting in an extreme decrease in productivity and a major hindrance to uniform dispersion of the compounded drug. Chlorosulfonated polyethylene (Hypalon)
As with other rubbers, vulcanizates with various physical properties can be obtained by combining vulcanizing agents, fillers, softeners, safety agents, etc. and varying them appropriately. The following formulations have been conventionally proposed.

[Kneading adhesion determination test method]

Water at about 50°C is passed through kneading rolls with a diameter of about 14 inches and a length of about 32 inches, and the gap between the rolls is adjusted as appropriate depending on the condition of kneading. Total amount of compound is approximately 2Kg
Design with. Wrap chlorosulfonated polyethylene around a roll, add rubber metal compounds (e.g. magnesium oxide, litharge, calcium hydroxide, etc.), then add anti-aging agents and pentaerythritol, then fillers, reinforcing agents, etc. is added, then a softener and a plasticizer are added, and finally a vulcanization accelerator is added (so-called subs, such as hardened animal and vegetable oils, are added before the metal oxide). The presence or absence of kneading adhesion is
Judgment is made based on the presence or absence of a condition that makes it difficult to peel off the mixed dough from the kneading machine. As a result of investigating various agents (kneading anti-tack agents) that have the effect of preventing kneading adhesion against kneading adhesion in the kneading operation of such formulations having kneading tackiness, the present inventors discovered that sucrose fatty acid ester Those containing fatty acid groups of saturated or unsaturated alkyl groups having 12 to 20 carbon atoms; Rice bran wax; Glycerol monostearate, glycerol monooleate; Polyoxyethylene sorbitan monooleate, monostearate and palmitate; Nonylphenol ether of polyethylene glycol from 9 to 140, stearic acid monoester and oleic acid monoester; molecular weight
Oxyethylene oxypropylene block copolymer from 2000 to 8000; HLB (Hydrophile
It has been found that those having a Lipophile Balance) value of 10 or less are particularly effective as kneading anti-blocking agents. These inhibitors contain at least one of them in an amount of at least 0.3 per 100 parts by weight of chlorosulfonated polyethylene.
The effect is exerted by adding parts by weight.
Even if a large amount is used, the effect remains the same, but if an excessive amount is used, the physical properties of the vulcanized rubber during vulcanization change or deteriorate, making it unsuitable for the purpose, so there is naturally a limit to the amount used. When a compound containing a large amount of inhibitor is used, when the kneading temperature reaches a high temperature, for example, 100°C, the dough often becomes crumbly like clay and cannot be kneaded. The dough itself can be reused as a master batch of kneaded anti-blocking agent in other formulations. There are other agents other than those mentioned above that are effective in preventing adhesion during kneading. However, for example, stearic acid and its metal salts, such as zinc stearate, and MOLD WIZ 21G, which is called a lubricant (Axel Plastics Res.
Lab. products) and Structor WB16 (Schill
and Seilacher's product) may have the main effect of preventing adhesion during kneading, but at the same time it causes increased scorch properties, inhibits vulcanization, etc., and has undesirable adverse effects on the physical properties of the vulcanized product and the final product. The above kneaded anti-blocking agent of the present invention does not have such drawbacks and can be used while maintaining good storage stability, easy processability, and vulcanizability without any secondary adverse effects on the physical properties of the vulcanizate. and can reach the goal. The compounding antiblocking agent must be present in the chlorosulfonated polyethylene formulation during compounding. Therefore, these inhibitors can be mixed and blended before or during kneading or when adhesion occurs. Regardless of the method of addition, for example whether it is added all at once or added in parts, various types of inhibitors can be used in combination. Chlorosulfonated polyethylene or solid ingredients blended into chlorosulfonated polyethylene, such as metal oxides such as MgO, litharge, metal hydroxides such as Ca(OH) ₂ , fillers (also called reinforcing agents) It is also possible to use one or more of these which have been kneaded and treated with an anti-blocking agent. This preliminary processing is, for example,
Direct use of at least one of these inhibitors,
or by treatment such as mixing, heating, coating, adhering, spraying, dipping, kneading, etc. with chlorosulfonated polyethylene and/or one or more of the solid compounding ingredients with the aid of solvents, water, etc. Therefore, it is a matter of unity. Normally, chlorosulfonated polyethylene is in solid form (veil, chip, powder, etc.), but in the chlorosulfonation reaction step before polymer separation, it is used as a solution in an organic solvent (often carbon tetrachloride) or as an aqueous solution. It is treated as an emulsion, which is separated from the solution and dried to form a solid. Therefore, as a preferred embodiment of the present invention, it is possible to make the chlorosulfonated polyethylene contain the kneading anti-tack agent in advance by appropriately mixing the kneading anti-tack agent in any of these steps. be. Examples of the pretreatment method using the kneaded anti-tack agent include the following methods (details of these are shown in Examples below). Treatment 1: Chlorosulfonated polyethylene (for example, Hypalon, manufactured by DuPont) and a kneaded anti-blocking agent are roll kneaded in advance in a predetermined ratio and stored at room temperature. Treatment 2: A predetermined proportion of kneaded anti-blocking agent is applied to the surface of chlorosulfonated polyethylene, placed in an oven at 80°C for about 2 hours, and then left at room temperature. Treatment 3: A predetermined amount of kneaded anti-blocking agent is mixed in advance with magnesium oxide (for example, MgO #150 manufactured by Kyowa Mag Co., Ltd.), kept in an oven at 82° C. for about 2 hours, and then cooled to room temperature. Processing 4: Dixie clay, which is one of the fillers, and a kneaded anti-blocking agent are mixed in advance, left to stand in a 75°C oven for 1.5 hours, and then allowed to cool at room temperature. Treatment 5: Precipitated calcium carbonate (for example, Hakuenka CC manufactured by Shiraishi Calcium Co., Ltd.) and a kneaded anti-blocking agent are mixed in advance, kept in an oven at 80°C for 2 hours, and then left at room temperature. Process 6: Add an anti-blocking agent by kneading into a carbon tetrachloride solution (approximately 5-20% by weight) containing chlorosulfonated polyethylene, separate the solvent on a drum dryer (150℃), and cut the dried rubber. and store it. The rubber used in the present invention is a blend of chlorosulfonated polyethylene and other rubbers containing 80% or more of this. Chlorosulfonated polyethylene is a useful synthetic rubber that has excellent weather resistance, chemical resistance, and colorability, and provides beautiful brightly colored products. It can be used suitably. The kneading machine may be an ordinary rubber roll or Banbury, and there are no restrictions on the type of kneading machine. The order of kneading procedures is practically determined depending on the characteristics of the rubber and ease of operation. Chlorosulfonated polyethylene is formed into a sheet using a kneading machine, and metal oxides or hydroxides constituting the vulcanization system, pentaerythritol, anti-aging agents, etc. are added and mixed, followed by fillers and softeners (or plasticizers). , and then a vulcanization accelerator, but there are no restrictions.
The upside down method is said to be effective in Banbury kneading. If the temperature of the dough rises during kneading and the dough sticks to the kneading machine, it is necessary to temporarily stop adding ingredients or kneading, and restart kneading after the dough has cooled down. do not have. In the present invention, as the compounding agent, those commonly used for rubber and commercially available agents can be appropriately selected and used. Examples are given below. Examples of metal oxides used in the vulcanization system include magnesium oxide (MgO) and litharge (PbO), metal hydroxides such as calcium hydroxide, and vulcanization accelerators such as TRA (dipentamethylene). thiuram tetrasulfide), DM (dibenzothiazyl disulfide), TT (tetramethylthiuram disulfide), TS (tetramethylthiuram monosulfide), D (diphenylguanidine), CZ (N-cyclohexyl) -2-benzothiazylsulfenamide) and BZ (zinc di-n-butyldithiocarbamate). Fillers or reinforcing agents include hard clay or Dixie clay (Vanderbilt, USA);
Clay RC-32 (Thiele Kaolin, USA), Samson Clay (Takagi Clay Research Institute), etc.; White gloss of surface treated precipitated calcium carbonate - CC, -DD, -O
(Shiraishi Calcium Co., Ltd.), MSK-C (Maruo Calcium Co., Ltd.); Titanium White (Ishihara Sangyo), etc.; Aerosil as white carbon (Nippon Aerosil Co., Ltd.), Carplex 80 (Shionogi Pharmaceutical Co., Ltd.), Tokusil U (Tokuyama Soda), Nipsil Carbon blacks such as VN3 (Nippon Silica Co., Ltd.) are used. Process oils such as aromatic JSO are used as softeners (plasticizers) to adjust the hardness, tensile strength, and elongation of the vulcanizate or the viscosity of the kneaded dough.
-790 (Nippon Sun Oil Co., Ltd.), naphthene-based RPO oil (Nippon Sun Oil Co., Ltd.), chlorinated paraffin Empara #40 (Ajinomoto Co., Ltd.), ester-based DOP (dioctyl phthalate), DOS (dioctyl sebacate, DOA ( Dioctyl adipate), DOZ (dioctyl azelate), etc.Resins such as coumaron resin, phenol resin, terpene phenol resin, etc. can also be used as needed.The amount of these mainly oily components added depends on the bleed. There is naturally a limit to the amount added in order to prevent this from occurring, but generally aromatic process oils have a limit of about
55phr, about 15~ with naphthenic process oil
It is said to be 20phr. Tables 2 to 7 below collectively show examples and comparative examples for more specifically explaining the composition and method of the present invention. Unless otherwise specified, the numbers in the table are parts by weight of the ingredients per 100 parts by weight of rubber. The formulations in the Examples were made according to the above-mentioned kneading tack evaluation test method unless otherwise specified in the table. The processing numbers in the table mean the aforementioned preliminary processing numbers. Examples in which no processing number is indicated mean that all components were kneaded at once. The kneading was carried out using a kneading machine whose temperature was controlled at 50 to 60°C. As the kneading machine, a roll was used in all cases except for the Banbury used in Example 31. Table 8 shows the results of measuring the physical properties of vulcanized products made from the kneaded doughs obtained in the above Examples (excluding Example 11). From the same table, it can be seen that according to the present invention, practical physical properties can be obtained regardless of the kneaded anti-tack agent. Table 9 shows the case where no anti-blocking agent is used (Comparative Example 6) and the known anti-blocking agents namely stearic acid (Comparative Example 7), calcium stearate (Comparative Example 8) and zinc stearate (Comparative Example 9).
This figure illustrates the vulcanization behavior and physical properties when each of these is used. From the same table, it can be seen that when stearic acid, calcium stearate, or zinc stearate is used in the Resurge formulation, scorch becomes faster.

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Claims (1)

[Scope of Claims] 1. Consisting of chlorosulfonated polyethylene, a vulcanizing agent, a filler, a softener, and at least one kneading anti-blocking agent in an amount of at least 0.3 parts by weight per 100 parts by weight of chlorosulfonated polyethylene; The inhibitor is a sucrose fatty acid ester with 12 to 20 carbon atoms.
Containing fatty acid groups of saturated or unsaturated alkyl groups, rice bran wax, glycerol monostearate, glycerol monooleate, polyoxyethylene sorbitan monooleate, monostearate, palmitate, polymerization degree from 9 to 140
nonylphenol ether of polyethylene glycol, stearic acid monoester, oleic acid monoester, oxyethylene oxypropylene block copolymer with a molecular weight of 2,000 to 8,000, or fatty acid having a saturated or unsaturated alkyl group with 8 to 18 carbon atoms. 1. A scorch-resistant, easily vulcanizable chlorosulfonated polyethylene compound composition having anti-kneading adhesion properties, comprising a sorbitan fatty acid ester having an HLB value of 10 or less. 2. A mixture of 100 parts by weight of chlorosulfonated polyethylene and at least 0.3 parts by weight of at least one kneaded anti-blocking agent, a vulcanizing agent, a filler and a softening agent, and as the anti-blocking agent. Sucrose fatty acid esters containing saturated or unsaturated alkyl fatty acid groups with 12 to 20 carbon atoms, rice bran wax, glycerol monostearate, glycerol monooleate, polyoxyethylene sorbitan monooleate, Palmitate, nonylphenol ether of polyethylene glycol with a degree of polymerization of 9 to 140, stearic acid monoester, oleic acid monoester, oxyethylene oxypropylene block copolymer with a molecular weight of 2000 to 8000, or saturated carbon number 8 to 18 or a scorch-resistant, easily vulcanizable, chlorosulfonated polyethylene blend composition having anti-kneading properties, characterized in that a sorbitan fatty acid ester of a fatty acid having an unsaturated alkyl group with an HLB value of 10 or less is used. Manufacturing method.