Method for producing mixture of aqueous dispersion composition, method for producing dip molded body, and mixture of aqueous dispersion composition

Abstract

Provided is a method capable of preparing a chlorosulfonated polyolefin product which uses no organic solvent to the extent possible, where the chlorosulfonated polyolefin product also has excellent strength in addition to a practically durable hardness and elongation resistance.　Specifically, provided is a method for producing a mixture of an aqueous dispersion composition, the method comprising mixing a plurality of aqueous dispersion compositions each containing a chlorosulfonated polyolefin.

Description

Method for producing a mixture of water-dispersed composition, method for producing a dip-molded body, and mixture of water-dispersed composition

[0001] The present disclosure relates to a method for producing a mixture of a water-dispersed composition, a method for producing a dip-formed article, and a mixture of a water-dispersed composition.

[0002] Rubber gloves and sacks are widely used for household purposes, industrial purposes such as the food industry and electronic component manufacturing, and medical purposes. Their basic function is to protect the hands from acids, alkalis, poisonous and other chemicals, organic solvents, as well as blades, heat, and radiation. Other important functions include comfort even with prolonged use and resistance to deterioration even after repeated bending. Therefore, in addition to a level of hardness sufficient for practical use, they also require strength and stretch resistance.

[0003] Chlorosulfonated polyolefin is a type of rubber that can be used as a raw material for producing products such as rubber gloves, and the resulting products have excellent resistance to strong acids and strong alkalis. However, conventionally, preparing products such as rubber gloves using chlorosulfonated polyolefin requires the use of a large amount of organic solvents, and from the viewpoint of environmental protection, etc., a production method that uses less organic solvents is desired. From this viewpoint, for example, a production method using dip molding with chlorosulfonated polyolefin latex has been studied (e.g., Patent Documents 1 to 3).

[0004] International Publication No. WO 2023 / 234238 International Publication No. WO 2024 / 070750 JP 2024-047287 A

[0005] The present inventors have investigated the use of a mixture of multiple chlorosulfonated polyolefins to adjust the hardness of dip-molded articles obtained using chlorosulfonated polyolefins, but have found that this results in a decrease in the strength of the resulting dip-molded articles. Therefore, the present inventors have conducted further investigations with the aim of providing a method for using multiple chlorosulfonated polyolefins to adjust the hardness of dip-molded articles and to suppress the decrease in strength of dip-molded articles.

[0006] The present disclosure includes, for example, the subject matter described in the following paragraphs. Item 1. A method for producing a mixture of water-dispersed compositions, comprising mixing a plurality of water-dispersed compositions each containing a chlorosulfonated polyolefin of different hardness. Item 2. The method described in Item 1, wherein the plurality of water-dispersed compositions comprise water-dispersed composition A and water-dispersed composition B, and the hardness (Shore A) of the chlorosulfonated polyolefin contained in water-dispersed composition A is different from the hardness (Shore A) of the chlorosulfonated polyolefin contained in water-dispersed composition B. Item 3. The method described in Item 1, wherein the plurality of water-dispersed compositions comprise water-dispersed composition A and water-dispersed composition B, and water-dispersed composition A is a water-dispersed composition containing a chlorosulfonated polyolefin with a hardness (Shore A) of 60 or more, and water-dispersed composition B is a water-dispersed composition containing a chlorosulfonated polyolefin with a hardness (Shore A) of less than 60. Item 4. Item 1. The method according to Item 1, wherein the plurality of water-dispersed compositions comprise water-dispersed composition A and water-dispersed composition B, wherein water-dispersed composition A is a water-dispersed composition containing a chlorosulfonated polyolefin having a hardness (Shore A) of 60 to 100, and water-dispersed composition B is a water-dispersed composition containing a chlorosulfonated polyolefin having a hardness (Shore A) of 20 or more and less than 60. Item 5. The method according to any one of Items 1 to 4, wherein the chlorosulfonated polyolefin is chlorosulfonated polyethylene. Item 6. A method for producing a dip-molded article, comprising immersing a mold in a mixture of water-dispersed compositions produced by the method according to any one of Items 1 to 5. Item 7. A mixture of water-dispersed compositions produced by the method according to any one of Items 1 to 5. Item a. A mixture of water-dispersed compositions each containing a chlorosulfonated polyolefin of a different hardness. Item b. Item a. The mixture according to Item a, wherein the plurality of water-dispersed compositions include a water-dispersed composition A and a water-dispersed composition B, and the hardness (Shore A) of the chlorosulfonated polyolefin contained in the water-dispersed composition A is different from the hardness (Shore A) of the chlorosulfonated polyolefin contained in the water-dispersed composition B.Item c. The mixture according to Item a, wherein the plurality of water-dispersed compositions comprise water-dispersed composition A and water-dispersed composition B, wherein water-dispersed composition A is a water-dispersed composition containing a chlorosulfonated polyolefin having a Shore A hardness of 60 or more, and water-dispersed composition B is a water-dispersed composition containing a chlorosulfonated polyolefin having a Shore A hardness of less than 60. Item d. The mixture according to Item a, wherein the plurality of water-dispersed compositions comprise water-dispersed composition A and water-dispersed composition B, wherein water-dispersed composition A is a water-dispersed composition containing a chlorosulfonated polyolefin having a Shore A hardness of 60 to 100, and water-dispersed composition B is a water-dispersed composition containing a chlorosulfonated polyolefin having a Shore A hardness of 20 or more but less than 60. Item e. The mixture according to any one of Items a to d, wherein the chlorosulfonated polyolefin is chlorosulfonated polyethylene. Item f. A method for producing a dip-molded article, comprising dipping a mold in the mixture according to any one of Items a to e.

[0007] The present invention provides a chlorosulfonated polyolefin product that uses multiple chlorosulfonated polyolefins and yet has practically sufficient hardness, excellent breaking strength, and excellent breaking elongation. The chlorosulfonated polyolefin product can be prepared, for example, by dip-molding a mixture obtained by mixing multiple aqueous dispersion compositions containing chlorosulfonated polyolefins with different hardnesses.

[0008] Each embodiment included in the present disclosure will be described in more detail below. The present disclosure preferably includes a method for producing a mixture of water-dispersed compositions, which includes mixing a plurality of water-dispersed compositions, a mixture of water-dispersed compositions obtained by the production method, and use of the mixture of water-dispersed compositions, but is not limited thereto. The present disclosure includes all that is disclosed in the present specification and that can be recognized by a person skilled in the art.

[0009] A method for producing a mixture of water-dispersed compositions encompassed by the present disclosure includes mixing a plurality of water-dispersed compositions, each containing a chlorosulfonated polyolefin. This production method may also be referred to as the method for producing a mixture of water-dispersed compositions disclosed herein. The water-dispersed composition containing a chlorosulfonated polyolefin is a dispersion composition in which a chlorosulfonated polyolefin is dispersed in water, and is preferably an emulsion (particularly a latex).

[0010] In the method for producing a mixture of water-dispersed compositions disclosed herein, as described above, multiple pre-prepared water-dispersed compositions containing chlorosulfonated polyolefins are mixed. The mixing is performed by mixing two or more (preferably 2, 3, 4, or 5) water-dispersed compositions containing chlorosulfonated polyolefins. The chlorosulfonated polyolefins contained in each water-dispersed composition to be mixed may be different from each other, for example, differing in hardness (preferably (Shore A)). In the method for producing a water-dispersed composition disclosed herein, the multiple water-dispersed compositions preferably include water-dispersed composition A and water-dispersed composition B, and the hardness of the chlorosulfonated polyolefin contained in water-dispersed composition A is preferably different from the hardness of the chlorosulfonated polyolefin contained in water-dispersed composition B. The hardness of the chlorosulfonated polyolefin is typically a hardness (Shore A) measured by the following method. That is, the hardness (Shore A) of the chlorosulfonated polyolefin contained in water-dispersed composition A is preferably different from the hardness (Shore A) of the chlorosulfonated polyolefin contained in water-dispersed composition B.

[0011] The hardness (Shore A) of the chlorosulfonated polyolefin is measured as follows: The chlorosulfonated polyolefin to be measured is subjected to a temperature of 160°C and 20 kgf / cm ２The test piece is heated and pressed at 400°C to form a 1 mm thick sheet, and the resulting sheet is cut into multiple 1 cm square test pieces. These are stacked to a thickness of 6 to 7 mm, and a pressure plate is brought into contact with the test piece so that the indenter of a durometer type A is perpendicular to the surface of the stacked test piece. After 3 seconds, the durometer value is read to measure the hardness (Shore A). Measurements are performed at 25°C. For example, a "GS-709" (Teclock Corporation) can be used as the durometer type A.

[0012] The hardness (Shore A) of the chlorosulfonated polyolefin contained in the aqueous dispersion composition A is preferably 60 or more. The upper limit of the hardness (Shore A) is not particularly limited as long as the effects of the production method of the present disclosure are not impaired, and may be, for example, 100. The upper or lower limit of the range (60 to 100) may be, for example, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99. The range may be, for example, 62 to 90, 63 to 85, or 63 to 80.

[0013] The hardness (Shore A) of the chlorosulfonated polyolefin contained in the aqueous dispersion composition B is preferably less than 60. The lower limit of the hardness (Shore A) is not particularly limited as long as the effects of the production method of the present disclosure are not impaired, and may be, for example, 20. The upper or lower limit of this range (20 or more and less than 60) may be, for example, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, or 59. The range may be, for example, 20 to 59, 25 to 55, or 30 to 50.

[0014] In the method for producing a mixture of water-dispersed compositions according to the present disclosure, the ratio of the amounts of the multiple water-dispersed compositions to be mixed can be appropriately set depending on the desired physical properties (e.g., the hardness of a molded product produced from the resulting mixture). For example, when producing a molded product (e.g., a rubber glove) from a mixture obtained by mixing at least the water-dispersed composition A and the water-dispersed composition B, the amounts of each water-dispersed composition can be set so that the ratio of the solid content by mass of water-dispersed composition A to the solid content by mass of water-dispersed composition B (i.e., the solid content mass ratio) is preferably 95:5 to 65:35, more preferably 90:10 to 70:30, and even more preferably 90:10 to 75:25. The solid content concentration in the water-dispersed composition can be considered the concentration of the chlorosulfonated polyolefin contained therein. The solid content concentration can also be determined by taking 2 g of the water-dispersed composition, drying it at 120°C for 1 hour to remove the water, and then measuring the mass of the residue.

[0015] In the method for producing a mixture of water-dispersed compositions according to the present disclosure, particularly when the water-dispersed composition A and the water-dispersed composition B are used, (i) a water-dispersed composition containing a chlorosulfonated polyolefin that is harder than those contained in the water-dispersed composition A and the water-dispersed composition B, (ii) a water-dispersed composition containing a chlorosulfonated polyolefin that is softer than those contained in the water-dispersed composition A and the water-dispersed composition B, or (iii) a water-dispersed composition containing a chlorosulfonated polyolefin having a hardness (Shore A) between those contained in the water-dispersed composition A and the water-dispersed composition B. When these water-dispersed compositions (i) to (iii) that can be further mixed are used, one type may be used alone or two or more types may be used in combination.

[0016] Chlorosulfonated polyolefins can be obtained by chlorinating and chlorosulfonating polyolefins, including polymers or copolymers of α-olefins and copolymers of α-olefins with other polymerizable components.

[0017] Examples of α-olefins include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, etc. Other polymerizable components include chain dienes such as isoprene, 1,3-butadiene, 1,4-hexadiene, 1,6-octadiene, and 2-methyl-1,5-hexadiene; cyclic dienes such as 1,4-cyclohexadiene, dicyclopentadiene, 5-vinyl-2-norbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, and 6-chloromethyl-5-isopropenyl-2-norbornene; and vinyl compounds such as vinyl acetate, vinyl chloride, acrylonitrile, styrene, methyl acrylate, and methyl methacrylate.

[0018] The chlorosulfonated polyolefin is preferably a chlorosulfonated α-olefin polymer. In the chlorosulfonated α-olefin polymer, one α-olefin may be used alone or two or more α-olefins may be used. When two or more α-olefins are used, one of them is preferably ethylene.

[0019] More specific examples of chlorosulfonated polyolefins include chlorosulfonated polyethylene, chlorosulfonated ethylene-α-olefin copolymers, and chlorosulfonated α-olefin polymers. Note that the "α-olefin" in chlorosulfonated ethylene-α-olefin copolymers and chlorosulfonated α-olefin polymers refers to α-olefins other than ethylene. A preferred example of the α-olefin other than ethylene here is propylene. That is, a preferred example of the chlorosulfonated ethylene-α-olefin copolymer is chlorosulfonated ethylene-propylene copolymer, and a preferred example of the chlorosulfonated α-olefin polymer is chlorosulfonated propylene polymer.

[0020] The chlorosulfonated polyolefins may be used alone or in combination of two or more.

[0021] The sulfur content in the chlorosulfonated polyolefin is preferably 0.5% by mass or more, more preferably 0.8% by mass or more, preferably 2.0% by mass or less, more preferably 1.5% by mass or less, and preferably 0.5 to 2.0% by mass, more preferably 0.8 to 1.5% by mass.

[0022] The chlorine content in the chlorosulfonated polyolefin of the present disclosure is not particularly limited, but is preferably 10% by mass or more, more preferably 20% by mass or more. It is also preferably 50% by mass or less, more preferably 45% by mass or less. It is also preferably 10 to 50% by mass, more preferably 20 to 45% by mass.

[0023] The sulfur content and chlorine content of the chlorosulfonated polyolefin can be measured by the oxygen flask combustion method.

[0024] Methods for chlorinating and chlorosulfonating polyolefins include a solution method in which the polyolefin is dissolved in an organic solvent to carry out a homogeneous system, a suspension method in which the polyolefin is suspended in a solvent to carry out the reaction, a melt method in which the polyolefin is reacted in a molten state, and a gas-phase method in which the polyolefin is suspended in a gas phase to carry out the reaction.Of these, the solution method is preferred from the viewpoint of uniform chlorination and chlorosulfonation.The chlorinating agent and chlorosulfonating agent used can be a combination of chlorine gas and sulfurous acid gas, a combination of chlorine gas and sulfuryl chloride, or sulfuryl chloride alone.The chlorosulfonation reaction can be carried out by using a chlorinating agent, a chlorosulfonating agent, a radical generator, and, if necessary, a co-catalyst such as pyridine.

[0025] Commercially available chlorosulfonated polyolefins may be used. Examples of commercially available products include those sold by Tosoh Corporation under the trade names "TOSO-CSM" and "extos." More specifically, examples include Tosoh Corporation's "TOSO-CSM" grades TS-430, TS-530, TS-830, TS-930, TS-320, TS-340, and CN-1500, and "extos" grade ET-8010. Note that chlorosulfonated polyolefins with different trade names and grades have different hardness (Shore A).

[0026] The water-dispersed composition containing the chlorosulfonated polyolefin preferably contains a chlorosulfonated polyolefin, an aqueous dispersion medium (particularly water), and an emulsifier. The water-dispersed composition containing the chlorosulfonated polyolefin is more preferably a chlorosulfonated polyolefin latex.

[0027] Examples of methods for producing an aqueous dispersion composition containing a chlorosulfonated polyolefin include a method of melting the chlorosulfonated polyolefin and dispersing it in water containing an emulsifier, and a method of dissolving the chlorosulfonated polyolefin in an organic solvent, dispersing the resulting solution in water containing an emulsifier, and then removing the organic solvent. The latter method is preferred from the viewpoint of ease of controlling the particle size of the aqueous dispersion composition (particularly latex) containing a chlorosulfonated polyolefin.

[0028] Examples of the latter method include a phase inversion emulsification method in which water is added to a chlorosulfonated polyolefin dissolved in an organic solvent to form a water-in-oil (W / O) emulsion, and then water is added to invert the phase to form an oil-in-water (O / W) emulsion, or a forced emulsification method in which a chlorosulfonated polyolefin dissolved in an organic solvent is mechanically dispersed (by stirring) in water in the presence of an emulsifier using an emulsifier. These methods may be used alone or in combination.

[0029] The organic solvent is not particularly limited as long as it can dissolve the chlorosulfonated polyolefin and is immiscible with water, and examples thereof include aliphatic hydrocarbon solvents such as hexane, heptane, and cyclohexane; aromatic hydrocarbon solvents such as benzene, toluene, and xylene; chlorinated hydrocarbon solvents such as chloroform and 1,2-dichloroethane; alcohol solvents such as 1-butanol and isobutanol; ester solvents such as ethyl acetate, isopropyl acetate, and n-butyl acetate; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; and ether solvents such as diisopropyl ether, dibutyl ether, and anisole. Of these, toluene is preferred. These organic solvents may be used alone or in combination of two or more.

[0030] The amount of organic solvent used is not particularly limited, but is preferably set so that the concentration of chlorosulfonated polyolefin becomes 5 to 25% by mass, more preferably 8 to 20% by mass.

[0031] When an emulsifier is used, the emulsifier is not particularly limited, but anionic emulsifiers and nonionic emulsifiers are preferred, and anionic emulsifiers are particularly preferred.

[0032] Examples of the anionic emulsifier include polyoxyalkylene alkyl ether sulfates, polyoxyalkylene alkyl phenyl ether sulfates, alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl diphenyl sulfonates, α-olefin sulfonates, alkyl sulfate ester salts, naphthalene sulfonate formalin condensates, dialkyl sulfosuccinates, polyoxyethylene alkyl ether acetates, rosinate salts, and fatty acid salts. As the salts of these, for example, alkali metal salts are preferred, and sodium salts and potassium salts are more preferred. Among these, from the viewpoint of excellent stability of the water-dispersed composition (particularly latex), polyoxyalkylene alkyl ether sulfates and polyoxyalkylene alkylphenyl ether sulfates are preferred, and specific examples thereof include polyoxyethylene lauryl ether sodium sulfate, polyoxyethylene tridecyl ether sodium sulfate, polyoxyethylene myristyl ether sodium sulfate, polyoxypropylene lauryl ether sodium sulfate, polyoxypropylene tridecyl ether sodium sulfate, polyoxyethylene polyoxypropylene lauryl ether sodium sulfate, and polyoxyethylene polyoxypropylene tridecyl ether sodium sulfate.

[0033] When a fatty acid salt is used as the emulsifier, the fatty acid may be dissolved in a solution of chlorosulfonated polyolefin in the organic solvent, and an aqueous solution of a neutralizing agent may be mixed with the organic solvent solution to form a dispersion. Examples of the fatty acid include palmitic acid, stearic acid, oleic acid, and vaccenic acid, and examples of the neutralizing agent include sodium hydroxide, potassium hydroxide, ammonia, alkanolamine, and alkylamine.

[0034] Examples of the nonionic emulsifier include polyoxyalkylene alkyl esters, polyoxyalkylene alkyl ethers, polyoxylethylene derivatives, polyoxyalkylene alkylphenyl ethers, sorbitan alkyl esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, propylene glycol esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene hydrogenated castor oil, polyoxyethylene alkylamines, and alkyl alkanolamides.

[0035] The emulsifier may be used alone or in combination of two or more kinds. The amount of the emulsifier to be added is not particularly limited, but is preferably 0.1 to 15 parts by mass, more preferably 0.5 to 12 parts by mass, and particularly preferably 1 to 10 parts by mass, per 100 parts by mass of the chlorosulfonated polyolefin.

[0036] As the emulsifying apparatus, a known apparatus can be used, for example, a paddle mixer, a planetary mixer, a homomixer, a homogenizer, a disperser mixer, etc. The emulsifying apparatus may be of a batch type or a continuous type.

[0037] The temperature during emulsification can be appropriately set depending on the type of organic solvent used, and is usually about 5 to 70°C.

[0038] The organic solvent can be removed from the emulsion containing the organic solvent (the emulsion obtained by the above-described method) by distillation under normal pressure, reduced pressure, or increased pressure, for example. At this time, water can be removed simultaneously, if necessary, to adjust the concentration of the aqueous dispersion composition (particularly the latex). In this organic solvent removal operation, an antifoaming agent may be used to suppress foaming caused by the emulsifier. Examples of antifoaming agents include mineral oil-based antifoaming agents, silicone-based antifoaming agents, acetylene-based antifoaming agents, metal soap-based antifoaming agents, acrylic antifoaming agents, and fluorine-based antifoaming agents. Among these, acetylene-based antifoaming agents are preferred. These may be used alone or in combination of two or more. The amount of antifoaming agent used varies depending on the amount of emulsifier used, but is preferably 100 to 2000 wt ppm per 100 parts by mass of chlorosulfonated polyolefin. The antifoaming agent may be added to the emulsion before the removal operation or as needed during the removal operation. The addition method may include adding the antifoaming agent all at once, adding it dropwise, spraying it, or the like.

[0039] After removing the organic solvent, if water is to be further removed to adjust the concentration, it can be removed by a procedure such as distillation, centrifugation, membrane separation, or filtration.

[0040] The particle size of the chlorosulfonated polyolefin contained in the aqueous dispersion composition is not particularly limited, but the volume-based median particle size measured with a laser diffraction particle size distribution analyzer is preferably 0.1 to 10 μm, more preferably 0.3 to 5 μm, and particularly preferably 0.5 to 2 μm. When the particle size is within this range, an aqueous dispersion composition (particularly a latex) with excellent stability is more likely to be obtained. The particle size can be adjusted by the type and amount of the organic solvent and emulsifier, the amount of water used, and the operating conditions of the emulsification apparatus.

[0041] To enhance the stability of the aqueous dispersion composition (particularly latex) containing the chlorosulfonated polyolefin, additives such as dispersion stabilizers such as polyvinyl alcohol, polyvinylpyrrolidone, and hydroxyethyl cellulose, and stabilizers such as dibutylhydroxytoluene, 2,5-di-tert-butylhydroquinone, and bisphenol A-type epoxy resin may be added. Such additives may be added to the aqueous dispersion composition after preparation, or, depending on the type of additive, may be added to the organic solvent solution or water used for emulsification during the preparation of the aqueous dispersion composition. It is generally preferred that the additives be added as an individual or mixed aqueous solution or aqueous dispersion. When additives are added, a total amount of 0.1 to 10 parts by mass per 100 parts by mass of the chlorosulfonated polyolefin is preferably used.

[0042] The pH of the aqueous dispersion composition containing the chlorosulfonated polyolefin cannot be generally determined because it varies depending on the type and amount of the emulsifier and additives used. However, from the viewpoint of facilitating coagulation, the pH is preferably 2 or higher, and more preferably in the range of 3 to 8.

[0043] Furthermore, the chlorosulfonated polyolefin concentration of the aqueous dispersion composition containing the chlorosulfonated polyolefin is preferably 20 to 60% by mass. The upper or lower limit of this range may be, for example, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, or 59% by mass. For example, this range is more preferably 25 to 50% by mass. For example, the chlorosulfonated polyolefin concentrations of the above-mentioned aqueous dispersion compositions A and B are also preferably within this range.

[0044] The method for producing a mixture of water-dispersed compositions according to the present disclosure may further include the use of a water-dispersed composition of a different type of rubber (i.e., a rubber other than chlorosulfonated polyolefin) within a range that does not impair the effects of the method. For example, natural rubber latex, polybutadiene rubber latex, polyisoprene rubber latex, acrylonitrile-butadiene rubber latex, hydrogenated acrylonitrile-butadiene rubber latex, styrene-butadiene rubber latex, hydrogenated styrene-butadiene rubber latex, acrylic rubber latex, ethylene-propylene-diene rubber latex, chloroprene rubber latex, butyl rubber latex, chlorinated polyolefin rubber latex, fluororubber latex, epichlorohydrin rubber latex, silicone rubber latex, urethane rubber latex, etc. may be further mixed.

[0045] This mixing results in a mixture of a plurality of water-dispersed compositions. This mixture may be referred to as a mixture of water-dispersed compositions of the present disclosure. The mixture of water-dispersed compositions of the present disclosure is also one embodiment of a water-dispersed composition containing a chlorosulfonated polyolefin. The configuration of a preferred embodiment of the mixture of water-dispersed compositions of the present disclosure preferably satisfies the configuration of the water-dispersed composition containing a chlorosulfonated polyolefin described in detail above.

[0046] For example, the particle size of the chlorosulfonated polyolefin contained in the mixture of the aqueous dispersion composition of the present disclosure is not particularly limited, but the volume-based median particle size measured with a laser diffraction particle size distribution analyzer is preferably 0.1 to 10 μm, more preferably 0.3 to 5 μm, and particularly preferably 0.5 to 2 μm.

[0047] For example, the pH of the mixture of the aqueous dispersion composition of the present disclosure is preferably 2 or higher, and more preferably in the range of 3 to 8.

[0048] For example, the chlorosulfonated polyolefin concentration in the mixture of the aqueous dispersion composition of the present disclosure is preferably 20 to 60% by mass. The upper or lower limit of this range may be, for example, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, or 59% by mass. For example, the range is more preferably 25 to 50% by mass. Note that these are merely examples, and as described above, the mixture of the aqueous dispersion composition of the present disclosure may satisfy each of the components of the aqueous dispersion composition containing the chlorosulfonated polyolefin detailed above.

[0049] The quantitative ratio of the multiple water-dispersed compositions used in preparing the mixture of water-dispersed compositions of the present disclosure can be appropriately set depending on the desired physical properties (e.g., the hardness of the molded article produced from the resulting mixture). For example, when producing the mixture of water-dispersed compositions of the present disclosure using at least the water-dispersed composition A and the water-dispersed composition B, the amount of each water-dispersed composition can be set so that the [solid content mass of water-dispersed composition A]:[solid content mass of water-dispersed composition B] (i.e., solid content mass ratio) is preferably 95:5 to 65:35, more preferably 90:10 to 70:30, and even more preferably 90:10 to 75:25. The solid content concentration in the mixture of water-dispersed compositions can be considered the concentration of the chlorosulfonated polyolefin contained. The solid content concentration can also be determined by taking 2 g of the water-dispersed composition, drying it at 120 ° C. for 1 hour to remove the water, and then measuring the mass of the residue.

[0050] The mixture of the aqueous dispersion composition of the present disclosure can be preferably used, for example, as a dip-molding composition. When used as a dip-molding composition, further additives may be included, and preferably are included. Examples of additives include known additives such as surfactants, rheology modifiers, antioxidants, antifoaming agents, pH adjusters, chelating agents, vulcanizing agents, vulcanization accelerators, vulcanization accelerator assistants, acid acceptors, film-forming assistants, plasticizers, fillers, pigments, and gelling agents. These may be used alone or in combination of two or more.

[0051] Examples of surfactants include amino acid surfactants, alkylarylsulfonic acid surfactants, alkyl sulfate surfactants, and sulfosuccinic acid surfactants.

[0052] Preferred amino acid surfactants are compounds having an amide bond between a fatty acid and an amino acid salt. Preferred fatty acids include coconut oil fatty acids and C8 to C18 (C8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18) straight-chain or branched-chain fatty acids. Preferred amino acids include glutamic acid, aspartic acid, glycine, alanine, methylalanine, sarcosine, and methyltaurine. Preferred salts are alkali metal salts, more preferably sodium or potassium salts, and even more preferably sodium salts. More specifically, examples of the surfactant include glutamic acid surfactants such as N-coconut oil fatty acid glutamate, N-lauroyl glutamate, and N-myristoyl glutamate; alanine-based surfactants such as N-coconut oil fatty acid alanine salt, N-lauroyl alanine salt, N-coconut oil fatty acid methyl alanine salt, and N-lauroyl methyl alanine salt; sarcosine-based surfactants such as N-coconut oil fatty acid sarcosine salt and N-lauroyl sarcosine salt; glycine-based surfactants such as N-coconut oil fatty acid glycine salt and N-lauroyl glycine salt; aspartic acid-based surfactants such as N-coconut oil fatty acid aspartate, N-lauroyl aspartate, and N-myristoyl aspartate; and taurine-based surfactants such as N-coconut oil fatty acid methyl taurate, N-lauroyl methyl taurate, N-myristoyl methyl taurate, and N-stearoyl methyl taurate. As these salts, alkali metal salts are preferred, sodium salts or potassium salts are more preferred, and sodium salts are even more preferred. Among these, from the viewpoint of coagulation efficiency, taurine-based surfactants are preferred, and N-coconut oil fatty acid methyl taurate sodium is particularly preferred.

[0053] The alkylaryl sulfonic acid surfactant is preferably an alkylaryl sulfonic acid surfactant having a C8 to C18 (C8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18) linear or branched (preferably linear) alkyl group. The aryl is preferably benzene or naphthalene. More specific examples include linear or branched alkylbenzene sulfonic acid surfactants such as octylbenzene sulfonate, decylbenzene sulfonate, undecylbenzene sulfonate, dodecylbenzene sulfonate, and tetradecylbenzene sulfonate; and linear or branched alkylnaphthalene sulfonate surfactants such as butylnaphthalene sulfonate, octylnaphthalene sulfonate, decylnaphthalene sulfonate, and dodecylnaphthalene sulfonate. The salt is preferably an alkali metal salt, more preferably a sodium or potassium salt, and even more preferably a sodium salt. Among these, from the viewpoint of coagulation efficiency, linear alkylbenzenesulfonic acid surfactants having an alkyl group of C8 to C18 are preferred, and linear alkylbenzenesulfonic acid surfactants having an alkyl group of C10 to C14 are particularly preferred.

[0054] As the alkyl sulfate surfactant, alkyl sulfates having a C8 to C18 (C8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18) linear or branched alkyl group are preferred, and alkyl sulfates having a linear alkyl group are more preferred. More specific examples include linear alkyl sulfate surfactants such as octyl sulfate, decyl sulfate, undecyl sulfate, dodecyl sulfate, α-olefin (C12 to C14) sulfate, α-olefin (C14 to C16) sulfate, and stearyl sulfate; and branched alkyl sulfate surfactants such as 2-ethylhexyl sulfate and isostearyl sulfate. The salt is preferably an alkali metal salt, more preferably a sodium or potassium salt, and even more preferably a sodium salt. Among these, from the viewpoint of coagulation efficiency, C8 to C18 linear alkyl sulfates are preferred, and C10 to C14 linear alkyl sulfates are particularly preferred.

[0055] Examples of sulfosuccinic acid surfactants include monoalkyl sulfosuccinic acid surfactants such as monolauryl sulfosuccinate and monococonut oil fatty acid sulfosuccinate; and dialkyl sulfosuccinic acid surfactants such as diisobutyl sulfosuccinate, dihexyl sulfosuccinate, dioctyl sulfosuccinate, di(2-ethylhexyl) sulfosuccinate, dinonyl sulfosuccinate, and allyldodecyl sulfosuccinate. As the salt, alkali metal salts are preferred, sodium salts or potassium salts are more preferred, and sodium salts are even more preferred. Among these, from the viewpoint of coagulation efficiency, dialkyl sulfosuccinic acid surfactants are preferred, and sodium di(2-ethylhexyl) sulfosuccinate is particularly preferred.

[0056] Examples of rheology modifiers include polysaccharides such as cellulose, cellulose nanofibers, cellulose nanocrystals, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, carboxymethyl cellulose, chitin, chitosan, guar gum, and xanthan gum, water-soluble vinyl polymers such as polyacrylic acid, sodium polyacrylate, crosslinked polyacrylic acid, polyacrylamide, polyvinyl alcohol, polyvinyl methyl ether, and polyvinylpyrrolidone, and clay minerals such as montmorillonite, nontronite, saponite, beidellite, and hectorite. These may be used alone or in combination of two or more.

[0057] Examples of the antioxidant include phenol-based antioxidants such as dibutylhydroxytoluene, 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), and 2,5-di-tert-butylhydroquinone, amine-based antioxidants such as N-phenyl-1-naphthylamine and di(4-octylphenyl)amine, phosphorus-based antioxidants such as tris(nonylphenyl)phosphite, sulfur-based antioxidants such as dilauryl thiodipropionate, 2-mercaptobenzimidazole and nickel dibutyldithiocarbamate, and bisphenol A-type epoxy resins. These can be used alone or in combination of two or more.

[0058] Examples of the defoaming agent include oil-based defoaming agents, mineral oil-based defoaming agents, silicone-based defoaming agents, polyether-based defoaming agents, etc. These may be used alone or in combination of two or more.

[0059] Examples of pH adjusters include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, ammonia, trimethylamine, triethanolamine, hydrochloric acid, sulfuric acid, phosphoric acid, citric acid, acetic acid, etc. These may be used alone or in combination of two or more.

[0060] Examples of the chelating agent include ethylenediaminetetraacetic acid, nitrilotriacetic acid, trans-1,2-diaminocyclohexanetetraacetic acid, diethylenetriaminepentaacetic acid, bis(aminoethyl)glycol ether-N,N,N',N'-tetraacetic acid, N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid, dihydroxyethylglycine, 1-hydroxyethane-1,1-diphosphonic acid, gluconic acid, citric acid, malic acid, tartaric acid, etc. These can be used alone or in combination of two or more.

[0061] Examples of vulcanizing agents include sulfur such as powdered sulfur, sulfur flowers, precipitated sulfur, and colloidal sulfur, organic peroxides such as di-tert-butyl peroxide and dicumyl peroxide, maleimide compounds such as N,N'-m-phenylene bismaleimide, quinoid compounds such as p-quinone dioxime and p,p'-dibenzoylquinone dioxime, metal compounds such as magnesium oxide and lead oxide, and polyhydric alcohol compounds such as pentaerythritol, dipentaerythritol, sorbitol, and trimethylolpropane. These can be used alone or in combination of two or more.

[0062] Examples of the vulcanization accelerator include diethyldithiocarbamic acid, dibutyldithiocarbamic acid, diphenyldithiocarbamic acid, sodium diethyldithiocarbamate, sodium dibutyldithiocarbamate, sodium diphenyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc diphenyldithiocarbamate, 2-mercaptobenzothiazole, zinc 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, 2-(4'-morpholino) dithiobenzothiazole, trimethylthiourea, N,N'-diethylthiourea, 1,3-diphenylguanidine, 1,3-di-o-tolylguanidine, N-cyclohexyl-2-benzothiazolylsulfenamide, N-oxydiethylene-2-benzothiazolylsulfenamide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram tetrasulfide, zinc isopropylxanthogenate, etc. These may be used alone or in combination of two or more.

[0063] Examples of the vulcanization accelerator include metal oxides such as zinc oxide and magnesium oxide, and fatty acids such as stearic acid and palmitic acid. These may be used alone or in combination of two or more.

[0064] Examples of the acid acceptor include metal oxides such as lead oxide, magnesium oxide, zinc oxide, and calcium oxide, metal hydroxides such as magnesium hydroxide, calcium hydroxide, and aluminum hydroxide, clay minerals such as hydrotalcite, and epoxy compounds such as phenyl glycidyl ether, epoxidized soybean oil, epoxidized castor oil, sorbitol polyglycidyl ether, epoxidized polybutadiene, and polyglycidyl methacrylate. These may be used alone or in combination of two or more.

[0065] Examples of the film-forming aid include propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol monoiso-butyl ether, ethylene glycol mono-tert-butyl ether, ethylene glycol monophenyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monoisopropyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol monoiso-butyl ether, diethylene glycol mono-tert-butyl ether, diethylene glycol monophenyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, triethylene glycol monobutyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dipropylene glycol mono-n-butyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, etc. These can be used alone or in combination of two or more.

[0066] Examples of plasticizers include animal and vegetable oil-based plasticizers such as castor oil, linseed oil, soybean oil, epoxidized linseed oil, epoxidized soybean oil, epoxidized fatty acid, hydrogenated castor oil, and polyoxyethylene hydrogenated castor oil; synthetic oil-based plasticizers such as poly-α-olefins (e.g., polybutadiene) and hydrogenated products thereof, isobutene oligomers and hydrogenated products thereof, and polyisobutylene and hydrogenated products thereof; mineral oil-based plasticizers such as paraffinic process oil and naphthenic process oil; liquid rubber-based plasticizers such as liquid isoprene rubber, liquid butadiene rubber, liquid styrene butadiene rubber, liquid ethylene-propylene-diene rubber, and liquid acrylic rubber; dibutyl phthalate, dioctyl phthalate, benzyl butyl phthalate, Examples of suitable plasticizers include ester-based plasticizers such as diisononyl phthalate, dibutyl adipate, diisobutyl adipate, dioctyl adipate, diisononyl adipate, dibutyl sebacate, dibutyl maleate, dioctyl maleate, dioctyl fumarate, tributyl citrate, tributyl acetylcitrate, tributyl phosphate, trioctyl phosphate, tricresyl phosphate, tributyl trimellitate, trioctyl trimellitate, benzyl benzoate, dodecyl benzoate, and polyester polyol; and ether-based plasticizers such as polyethylene glycol, polypropylene glycol, polyethylene glycol dimethacrylate, and polypropylene glycol dimethacrylate. Among these, from the viewpoint of suppressing bleed-out, reactive plasticizers having reactive groups (reactive groups capable of crosslinking chlorosulfonated polyolefins, specifically, for example, epoxy groups or olefin groups) are preferred, and epoxidized animal and vegetable oil-based plasticizers and liquid rubber-based plasticizers are particularly preferred. These may be used alone or in combination of two or more.

[0067] Examples of fillers include carbon fiber, cellulose fiber, carbon black, silica, talc, clay, calcium carbonate, titanium oxide, and barium sulfate.

[0068] Examples of pigments include carbon black, titanium oxide, chromium oxide, iron blue, amber, nickel titanium yellow, viridian, cobalt blue, phthalocyanine blue, phthalocyanine green, molybdenum orange, chrome yellow, anthraquinone, quinacridone, etc. These may be used alone or in combination of two or more.

[0069] Examples of gelling agents include sodium alginate, pectin (LM pectin, HM pectin), gellan gum (LA gellan gum, HA gellan gum), gum arabic, κ-carrageenan, ι-carrageenan, tragacanth gum, glucomannan, tremel gum, fucoidan, heparin, hyaluronic acid, rhamsan gum, diutan gum, sodium polyacrylate, etc. These may be used alone or in combination of two or more.

[0070] The amount of the additive contained in the mixture of the aqueous dispersion composition of the present disclosure is not particularly limited, but is preferably 5 to 50 parts by mass, and more preferably 5 to 30 parts by mass, per 100 parts by mass of the solid content (i.e., chlorosulfonated polyolefin) of the mixture of the aqueous dispersion composition of the present disclosure.

[0071] Furthermore, when a mixture of the aqueous dispersion composition of the present disclosure is used as a dip-molding composition, it may contain other rubber latexes to the extent that the effects of the composition are not impaired. Examples of such other latexes include natural rubber latex, isoprene rubber latex, butadiene rubber latex, chloroprene rubber latex, butyl rubber latex, styrene-butadiene rubber latex, acrylic rubber latex, acrylonitrile-butadiene rubber latex, silicone rubber latex, fluororubber latex, epichlorohydrin rubber latex, and olefin rubber latex. As described above, these latexes may also be used during mixing to prepare the mixture of the aqueous dispersion composition of the present disclosure. When these various rubber latexes are used in combination with a mixture of the aqueous dispersion composition of the present disclosure as a dip-molding composition, the content of the other rubbers is preferably less than the content of the chlorosulfonated polyolefin, and is, for example, preferably 50 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, 20 parts by mass or less, 10 parts by mass or less, or 5 parts by mass or less per 100 parts by mass of the chlorosulfonated polyolefin.

[0072] The mixture of the aqueous dispersion composition of the present disclosure may be aged (also referred to as pre-vulcanization) before being subjected to dip molding. The aging time cannot be determined in general because it depends on the type of additive and the aging temperature, but is preferably 1 to 7 days, more preferably 1 to 3 days. The aging temperature is preferably 10 to 50°C, more preferably 20 to 40°C.

[0073] After aging, it is preferable to store the mixture at a temperature of 30° C. or less until it is subjected to dip molding.

[0074] A dip-molded article can be preferably produced by immersing a mold (molding die) in a mixture of the aqueous dispersion composition of the present disclosure.

[0075] The mold used for dip molding can be a mold that corresponds to the desired three-dimensional shape and is integrally formed from ceramic, metal, glass, plastic, etc. The surface of the mold can be appropriately designed depending on the purpose of the dip-molded product, and may be finished with a matte finish or provided with other materials such as fibers or other types of rubber coatings. In addition, the mold may be preheated before being immersed in the mixture of the aqueous dispersion composition of the present disclosure.

[0076] It is preferable to use a coagulant to aggregate the rubber component before immersing the mold in the mixture of the water-dispersed composition of the present disclosure, or after removing the mold from the mixture of the water-dispersed composition of the present disclosure. Examples of methods for using the coagulant include immersing the mold in a solution of the coagulant (hereinafter also referred to as a coagulant liquid) before immersing it in the mixture of the water-dispersed composition of the present disclosure to adhere the coagulant to the mold, and immersing the mold in a coagulant liquid after immersing it in the mixture of the water-dispersed composition of the present disclosure. From the viewpoint of obtaining a dip-molded product with little thickness unevenness, it is preferable to immerse the mold in a solution of the coagulant before immersing it in the mixture of the water-dispersed composition of the present disclosure to adhere the coagulant to the mold.

[0077] Examples of coagulants include metal halides such as sodium chloride, potassium chloride, barium chloride, calcium chloride, magnesium chloride, zinc chloride, and aluminum chloride; metal nitrates such as sodium nitrate, potassium nitrate, barium nitrate, calcium nitrate, zinc nitrate, and aluminum nitrate; metal acetates such as sodium acetate, potassium acetate, barium acetate, calcium acetate, zinc acetate, and aluminum acetate; and water-soluble metal salts such as metal sulfates such as sodium sulfate, potassium sulfate, calcium sulfate, magnesium sulfate, and aluminum sulfate. Among these, polyvalent metal salts that generate polyvalent metal ions are preferred from the viewpoint of high coagulation power, and water-soluble polyvalent metal salts are more preferred. As the polyvalent metal, alkaline earth metals are preferred, with calcium, barium, and magnesium being more preferred, and calcium being particularly preferred. Furthermore, calcium chloride and calcium nitrate are particularly preferred as coagulants from the viewpoint of high solubility in water. These coagulants may be used alone or in combination of two or more.

[0078] The coagulant is preferably used in the form of an aqueous solution. This aqueous solution may further contain a water-soluble organic solvent such as methyl alcohol or ethyl alcohol, or a nonionic surfactant. The concentration of the coagulation liquid is not particularly limited, but is preferably 5 to 50 mass%, more preferably 10 to 40 mass%, and particularly preferably 15 to 35 mass%. The immersion time of the mold in the coagulation liquid is not particularly limited, but is usually preferably 5 to 300 seconds, more preferably 10 to 100 seconds.

[0079] After the mold is immersed in the coagulation liquid to adhere the coagulation liquid to the surface, the solvent of the coagulation liquid may be removed by drying. The drying temperature can be set appropriately depending on the type of solvent and salt used, and is preferably 60 to 150°C, and more preferably 80 to 120°C. The drying time is not particularly limited, but is preferably 1 to 600 seconds, and more preferably 5 to 300 seconds. Drying the coagulation liquid on the surface of the mold makes it easier to create a state in which the salt is uniformly adhered to the surface of the mold.

[0080] The time for immersing the mold in the mixture of the aqueous dispersion composition of the present disclosure can be appropriately set depending on the thickness of the molded article to be obtained (generally, the longer the immersion time, the thicker the molded article to be obtained tends to be), and is, for example, preferably 5 to 600 seconds, more preferably 10 to 300 seconds.

[0081] The thickness of the resulting molded article is not particularly limited, and may be, for example, 0.1 to 1.0 mm.

[0082] After the mold is removed from the mixture of the aqueous dispersion composition of the present disclosure, it is usually heated to dry the rubber film formed on the mold surface. The drying method is not particularly limited, and drying can be performed using a hot air heater, infrared heater, microwave heater, high-frequency heater, etc. The drying temperature is not particularly limited, but is preferably 50 to 160°C, more preferably 60 to 140°C, and particularly preferably 70 to 120°C. The drying time is also not particularly limited, but is preferably 1 to 120 minutes, more preferably 10 to 100 minutes, and particularly preferably 20 to 60 minutes.

[0083] Furthermore, if necessary, further heating may be performed to vulcanize the rubber film formed on the mold surface. The heating conditions during vulcanization are not particularly limited, but 60 to 200°C is preferred, 80 to 180°C is more preferred, and 100 to 160°C is particularly preferred. By setting the heating temperature within this range, it is possible to achieve an appropriate vulcanization rate and suppress deterioration of the rubber component due to excessive heating. The heating time for vulcanization may be selected appropriately depending on the heating temperature, and is usually 5 to 120 minutes. The heating method can be, for example, the same method as the heating method described above.

[0084] In addition, before or after heating the mold onto which the mixture of the aqueous dispersion composition of the present disclosure has been deposited, it is preferable to wash the mold with water or warm water to remove water-soluble impurities (e.g., excess emulsifier, surfactant, coagulant, uncoagulated latex, etc.). The temperature of the water or warm water used is preferably 20 to 80°C, more preferably 30 to 70°C. The washing time is preferably about 0.5 to 60 minutes.

[0085] The dip-molded article after drying (and further vulcanization, if necessary) is removed from the mold. Examples of methods for removal include peeling from the mold by hand, peeling from the mold using a peeling roller, and peeling from the mold using water pressure or compressed air pressure. After being removed from the mold, the dip-molded article may be further washed with water. Furthermore, if necessary, to prevent adhesion at the contact surfaces between dip-molded articles and to improve slippage during attachment and detachment, inorganic fine particles such as talc or calcium carbonate or organic fine particles such as cornstarch may be applied to the surface, an elastomer layer containing fine particles may be further formed on the surface, or the surface layer may be chlorinated.

[0086] The dip-formed article thus obtained (sometimes referred to as the dip-formed article of the present disclosure) has not only sufficient hardness for practical use but also excellent strength and elongation resistance, and is therefore particularly suitable for use as an article to be applied to fingers (e.g., gloves and sacks).

[0087] The dip-formed product of the present disclosure preferably has a breaking strength (MPa) of 10 or more, more preferably 10 to 40. The upper or lower limit of the range (10 to 40 MPa) may be, for example, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, or 39 MPa. For example, the range may be 11 to 35 MPa or 12 to 30 MPa. When the dip-formed product is a rubber glove, the range is preferably 12 to 30 MPa, more preferably 12 to 27 MPa.

[0088] Furthermore, the dip-formed article of the present disclosure preferably has a breaking elongation (%) of 400 or more, and more preferably 400 to 900. The upper or lower limit of the range (400 to 900 MPa) may be, for example, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700, 710, 720, 730, 740, 750, 760, 770, 780, 790, 800, 810, 820, 830, 840, 850, 860, 870, 880, or 890%. For example, the range may be 610 to 890% or 650 to 800%. When the dip-molded product is a rubber glove, the range is preferably 410 to 890%, more preferably 420 to 800%.

[0089] The breaking strength (MPa) and breaking elongation (%) of the dip-formed article of the present disclosure are measured by punching out a test piece into the shape of a JIS No. 4 dumbbell from the dip-formed article to be measured, and then conducting a tensile test on the test piece using an autograph at a measurement temperature of 25°C and a tensile speed of 300 mm / min. An example of an autograph that can be used is the "AGS-X" (Shimadzu Corporation).

[0090] Furthermore, the dip-formed product of the present disclosure preferably has a hardness (Shore A) of 40 or more, more preferably 40 to 70. The upper or lower limit of the range may be, for example, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, or 69. The range may be, for example, 45 to 60. When the dip-formed product is a rubber glove, the range is preferably 40 to 60, more preferably 45 to 60.

[0091] The hardness (Shore A) of the dip-molded article of the present disclosure can be measured in the same manner as the hardness (Shore A) of the chlorosulfonated polyolefin described above. That is, multiple test pieces measuring 1 cm square are cut from the dip-molded article to be measured, stacked to a thickness of 6 to 7 mm, and a pressure plate is brought into contact with the test pieces so that the indenter of a durometer type A is perpendicular to the surface of the stacked test pieces. After 3 seconds, the durometer value is read and the hardness (Shore A) is measured. The measurement is performed at 25°C. As a durometer type A, for example, a product name "GS-709" manufactured by Teclock Corporation can be used.

[0092] It is particularly preferable that the coating of the dip-formed article of the present disclosure satisfy all of the above-mentioned breaking strength (MPa), breaking elongation (%), and hardness (Shore A).

[0093] In this specification, the term "comprising" includes "consisting essentially of" and "consisting of." In addition, the present disclosure includes any and all combinations of the constituent elements described in this specification.

[0094] Furthermore, the various characteristics (properties, structures, functions, etc.) described in each embodiment of the present disclosure above may be combined in any way to identify the subject matter encompassed by the present disclosure, i.e., the present disclosure encompasses all subject matter consisting of any combination of the combinable characteristics described herein.

[0095] Hereinafter, embodiments of the present disclosure will be described in more detail with reference to examples, but the embodiments of the present disclosure are not limited to the following examples. In the following examples, chlorosulfonated polyethylene was used as the chlorosulfonated polyolefin. All of the chlorosulfonated polyethylene used was purchased from Tosoh Corporation.

[0096] <Evaluation Method> Each of the Production Examples, Examples, and Comparative Examples was evaluated by the following method. (Solid Content Concentration of Latex) 2 g of latex was sampled and dried at 120°C for 1 hour to remove moisture, and then the mass of the residue was measured to determine the amount of solid content (chlorosulfonated polyethylene). In this study, unless otherwise specified, the amount of solid content (e.g., concentration or mass ratio) refers to the amount of chlorosulfonated polyethylene.

[0097] (Median particle diameter of chlorosulfonated polyethylene in latex) The volume-based median particle diameter of chlorosulfonated polyethylene in latex was measured using a laser diffraction particle size distribution analyzer (trade name "SALD-2000J" manufactured by Shimadzu Corporation). The particle diameter here is a value calculated by assuming that a particle to be measured that shows the same diffraction and scattered light pattern as a sphere with a diameter of 1 μm is a particle diameter of 1 μm, regardless of its shape.

[0098] (Hardness (Shore A) of Raw Rubber) With reference to JIS K 6253-3:2023, the hardness (Shore A) of the raw rubber (chlorosulfonated polyethylene) used was measured as follows: Chlorosulfonated polyethylene was subjected to a test at 160°C and 20 kgf / cm ２The test piece was heated and pressed at 400°C to form a sheet with a thickness of 1 mm. The obtained sheet was cut into several test pieces with a size of 1 cm square, and stacked to a thickness of 6 to 7 mm. A pressure plate was brought into contact with the test piece so that the indenter of a durometer type A (manufactured by Teclock Corporation under the trade name "GS-709") was perpendicular to the surface of the stacked test piece, and the durometer value was read after 3 seconds to measure the hardness (Shore A). The measurement was carried out at 25°C.

[0099] (Hardness (Shore A) of Dip-Molded Article) With reference to JIS K 6253-3:2023, the hardness (Shore A) of the obtained dip-molded article was measured as follows. A number of test pieces measuring 1 cm square were cut from the obtained dip-molded article and stacked to a thickness of 6 to 7 mm. A pressure plate was brought into contact with the test pieces so that the indenter of a Durometer Type A (manufactured by Teclock Corporation under the trade name "GS-709") was perpendicular to the surface of the stacked test pieces, and the value of the Durometer was read after 3 seconds to measure the hardness (Shore A). The measurement was carried out at 25°C.

[0100] (Coating Strength) Test pieces were prepared by punching out the coating of the obtained dip-molded article into the shape of a JIS No. 4 dumbbell. The test pieces were subjected to a tensile test using an autograph (manufactured by Shimadzu Corporation under the trade name "AGS-X") at a measurement temperature of 25°C and a pulling rate of 300 mm / min, and the breaking strength (MPa) and breaking elongation (%) were measured.

[0101] <Production Example 1> A 500 mL separable flask was charged with 45 g of chlorosulfonated polyethylene having a hardness (Shore A) of 73 and a chlorine content of 23 mass%, 255 g of toluene, and 0.45 g of oleic acid, and the mixture was stirred at 85°C for 4 hours to dissolve uniformly, thereby preparing a rubber solution. Separately, 7.5 g of sodium polyoxyalkylene alkyl ether sulfate (NOF Corporation, trade name "Trax ET-314") and 0.188 g of potassium hydroxide were dissolved in 170 g of ion-exchanged water to prepare an aqueous emulsifier solution.

[0102] The entire amount of the emulsifier aqueous solution was added to the rubber solution, and the mixture was stirred and mixed for 10 minutes using a homomixer (T.K. Robomix, product name, manufactured by Primix Corporation) to obtain an emulsion. The rotation speed and temperature during stirring and mixing were set at 12,000 rpm and 40°C, respectively. The obtained emulsion was heated to 40-70°C under a reduced pressure of 40-90 kPa to distill off the toluene, and then concentrated using an ultrafilter (ultrafiltration membrane: flat membrane type, molecular weight cutoff: 200,000, material: polysulfone) to a solids concentration (chlorosulfonated polyethylene) of 40%, to obtain a chlorosulfonated polyethylene latex (median particle size: 0.9 μm).

[0103] <Production Example 2> The same operation as in Production Example 1 was performed, except that the chlorosulfonated polyethylene was changed to a chlorosulfonated polyethylene having a hardness (Shore A) of 40 and a chlorine content of 30 mass%, to obtain a chlorosulfonated polyethylene latex (median particle size: 1.1 µm).

[0104] <Production Example 3> A chlorosulfonated polyethylene latex (median particle size: 0.9 µm) was obtained by the same operation as in Production Example 1, except that the chlorosulfonated polyethylene was changed to a chlorosulfonated polyethylene having a hardness (Shore A) of 45 and a chlorine content of 35 mass%.

[0105] <Production Example 4> A chlorosulfonated polyethylene latex (median particle size: 1.1 µm) was obtained by performing the same operation as in Production Example 1, except that the chlorosulfonated polyethylene was changed to a mixture of 40.5 g of chlorosulfonated polyethylene having a hardness (Shore A) of 73 and a chlorine content of 23 mass%, and 4.5 g of chlorosulfonated polyethylene having a hardness (Shore A) of 40 and a chlorine content of 30 mass%.

[0106] <Production Example 5> A chlorosulfonated polyethylene latex (median particle size: 1.0 µm) was obtained by performing the same operation as in Production Example 1, except that the chlorosulfonated polyethylene was changed to a mixture of 36 g of chlorosulfonated polyethylene having a hardness (Shore A) of 73 and a chlorine content of 23 mass%, and 9 g of chlorosulfonated polyethylene having a hardness (Shore A) of 40 and a chlorine content of 30 mass%.

[0107] Production Example 6 A chlorosulfonated polyethylene latex (median particle size: 1.1 μm) was obtained by performing the same operation as in Production Example 1, except that the chlorosulfonated polyethylene was changed to a mixture of 31.5 g of chlorosulfonated polyethylene having a hardness (Shore A) of 73 and a chlorine content of 23 mass% and 13.5 g of chlorosulfonated polyethylene having a hardness (Shore A) of 40 and a chlorine content of 30 mass%.

[0108] Example 1 Preparation of Dip Molding Composition The chlorosulfonated polyethylene latex obtained in Production Example 1 and the chlorosulfonated polyethylene latex obtained in Production Example 2 were mixed so that the mass ratio of the solid contents contained therein was 90:10, thereby obtaining a latex. To the mixed latex, 7.5 parts by mass of sodium alkyl (C10-14) benzenesulfonate (Lion Corporation, trade name "Lipon LS-250") was added per 100 parts by mass of the chlorosulfonated polyethylene contained in the mixed latex, and the mixture was stirred until completely dissolved.

[0109] Thereafter, 3 parts by mass, in terms of solid content, of an aqueous sodium dibutyldithiocarbamate solution (manufactured by Ouchi Shinko Chemical Industry Co., Ltd., trade name "Noccela TP") and 10 parts by mass of triethylene glycol monobutyl ether (manufactured by Nippon Nyukazai Co., Ltd., trade name "Butyl Triglycol") were added, and the mixture was stirred until homogeneous, to obtain a dip molding composition.

[0110] (Production of Dip-Molded Body) A ceramic mold was immersed in a 35% by mass aqueous solution of calcium nitrate for 5 seconds, then removed and dried in a 120°C air dryer for 5 minutes. The ceramic mold was then immersed in the dip-molding composition for 5 minutes, then removed, and a rubber component was attached to the ceramic mold. The ceramic mold with the rubber component attached was dried in a 70°C air dryer for 1 hour and then immersed in 60°C hot water for 60 minutes. The ceramic mold was then dried in a 70°C air dryer for 4 hours and then heated at 120°C for 20 minutes. After cooling to room temperature, the coating was peeled off from the ceramic mold to obtain a dip-molded body. The ceramic mold used was a rectangular parallelepiped measuring 20 cm x 8 cm x 0.5 cm, and the thickness of the obtained dip-molded body was 0.30 mm.

[0111] Example 2 A latex mixture was obtained by mixing the chlorosulfonated polyethylene latex obtained in Production Example 1 and the chlorosulfonated polyethylene latex obtained in Production Example 2 so that the solid content mass ratio contained therein was 80:20. The same operation as in Example 1 was carried out except for changing to this mixed latex, and a dip-molded product having a thickness of 0.31 mm was obtained.

[0112] Example 3 A latex mixture was obtained by mixing the chlorosulfonated polyethylene latex obtained in Production Example 1 and the chlorosulfonated polyethylene latex obtained in Production Example 2 so that the solid content mass ratio contained therein was 70:30. The same operation as in Example 1 was carried out except for changing to this mixed latex, and a dip-molded product having a thickness of 0.30 mm was obtained.

[0113] Example 4 A latex mixture was obtained by mixing the chlorosulfonated polyethylene latex obtained in Production Example 1 and the chlorosulfonated polyethylene latex obtained in Production Example 3 so that the mass ratio of the solid contents contained therein was 50:50. The same operation as in Example 1 was carried out except for changing to this mixed latex, and a dip-molded article having a thickness of 0.29 mm was obtained.

[0114] <Reference Example 1> The same operation as in Example 1 was carried out, except that the chlorosulfonated polyethylene latex obtained in Production Example 1 was used without being mixed with any other latex, instead of the mixed latex, to obtain a dip-molded product having a thickness of 0.32 mm.

[0115] <Reference Example 2> The same operation as in Example 1 was carried out, except that the chlorosulfonated polyethylene latex obtained in Production Example 2 was used without being mixed with any other latex, instead of the mixed latex, to obtain a dip-molded product having a thickness of 0.30 mm.

[0116] <Reference Example 3> The same operation as in Example 1 was carried out, except that the chlorosulfonated polyethylene latex obtained in Production Example 3 was used without being mixed with any other latex, instead of the mixed latex, to obtain a dip-molded product having a thickness of 0.28 mm.

[0117] Comparative Example 1 The same operation as in Example 1 was carried out, except that the chlorosulfonated polyethylene latex obtained in Production Example 4 was used without being mixed with any other latex, instead of the mixed latex, to obtain a dip-molded product having a thickness of 0.33 mm.

[0118] Comparative Example 2 The same operation as in Example 1 was performed, except that the chlorosulfonated polyethylene latex obtained in Production Example 5 was used without being mixed with any other latex, instead of the mixed latex, to obtain a dip-molded product having a thickness of 0.31 mm.

[0119] Comparative Example 3 The same operation as in Example 1 was performed, except that the chlorosulfonated polyethylene latex obtained in Production Example 6 was used without being mixed with any other latex, instead of the mixed latex, to obtain a dip-molded product having a thickness of 0.30 mm.

[0120]

[0121] As shown in Table 1, it was found that by using two types of chlorosulfonated polyolefins with different hardness, a dip-molded product softer than that obtained from a chlorosulfonated polyolefin with a higher hardness can be obtained, and a dip-molded product with greater strength than that obtained from a chlorosulfonated polyolefin with a lower hardness can be obtained. Furthermore, it was found that in the method of mixing chlorosulfonated polyolefins with different hardnesses, a dip-molded product obtained from a mixed latex mixed after latex production has the same hardness as a dip-molded product obtained from a latex in which chlorosulfonated polyolefins with different hardnesses are mixed in the rubber solution production process, but has better breaking strength and breaking elongation. Note that the dip-molded product obtained in Reference Example 1 is considered to be too hard to be used as a rubber glove.

[0122] The present invention contributes to environmental protection by enabling the preparation of chlorosulfonated polyolefin products that have not only practical hardness but also excellent breaking strength and breaking elongation, using a method that uses a relatively small amount of organic solvent.

Claims

1. A method for producing a mixture of water-dispersed compositions, comprising mixing a plurality of water-dispersed compositions each containing a chlorosulfonated polyolefin of a different hardness.

2. The method according to claim 1, wherein the plurality of water-dispersed compositions include water-dispersed composition A and water-dispersed composition B, and the hardness (Shore A) of the chlorosulfonated polyolefin contained in water-dispersed composition A is different from the hardness (Shore A) of the chlorosulfonated polyolefin contained in water-dispersed composition B.

3. The method according to claim 1, wherein the plurality of water-dispersed compositions include water-dispersed composition A and water-dispersed composition B, wherein water-dispersed composition A is a water-dispersed composition containing a chlorosulfonated polyolefin having a hardness (Shore A) of 60 or more, and water-dispersed composition B is a water-dispersed composition containing a chlorosulfonated polyolefin having a hardness (Shore A) of less than 60.

4. The method according to claim 1, wherein the plurality of water-dispersed compositions include water-dispersed composition A and water-dispersed composition B, wherein water-dispersed composition A is a water-dispersed composition containing a chlorosulfonated polyolefin having a hardness (Shore A) of 60 to 100, and wherein water-dispersed composition B is a water-dispersed composition containing a chlorosulfonated polyolefin having a hardness (Shore A) of 20 or more but less than 60.

5. The method according to any one of claims 1 to 4, wherein the chlorosulfonated polyolefin is chlorosulfonated polyethylene.

6. A method for producing a dip-molded product, which comprises immersing a mold in a mixture of the water-dispersed composition produced by the method according to any one of claims 1 to 4.

7. A mixture of water-dispersed compositions produced by the method according to any one of claims 1 to 4.

8. A mixture of water-dispersed compositions, which is a mixture of a plurality of water-dispersed compositions each containing a chlorosulfonated polyolefin.

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