Stirring device, stirring method, composition for dip molding, and dip molding

Abstract

A stirring device 1 comprises a stirring propeller 3 that rotates to stir a fluid to be stirred which is stored in a stirring tank 2. The ratio L / D of a liquid surface height L in the height direction of the fluid to be stirred in the stirring tank 2 and the tank diameter D in the radial direction of the stirring tank 2 is 2 or more. The stirring propeller 3 comprises a plurality of blades 31-35 which are arranged apart from each other in the height direction. The blades 31-35 rotate to generate a flow of the fluid to be stirred that has a height-direction component, the flow being generated towards the bottom section 22 of the stirring tank 2. The closer are the plurality of blades 31-35 to the bottom section 22 of the stirring tank 2, the larger are the radial diameters of the blades.

Description

Stirring device, stirring method, dip-molding composition, and dip-molded product

[0001] The present disclosure relates to a stirring device and the like.

[0002] Patent Document 1 discloses an agitation device that produces a latex (also referred to as an emulsion) in which polymer (high molecular weight) particles are dispersed in a medium such as water by a polymerization reaction of a monomer in an agitation tank.

[0003] Japanese Patent Application Publication No. 10-33966

[0004] In order to efficiently release the reaction heat in the polymerization reaction (hereinafter also referred to as polymerization heat) outside the stirring vessel, for example, stirring vessels are often used in which the ratio L / D of the liquid level height L of the stirred fluid to the diameter D of the stirring vessel is 2 or more. In order to effectively stir the stirred fluid in such a vertically long stirring vessel, Patent Document 1 proposes the use of stirring blades with a special shape.

[0005] The present disclosure has been made in consideration of these circumstances, and aims to provide an agitation device, etc. that can effectively agitate the fluid to be stirred in a stirring tank without using a specially shaped agitator blade.

[0006] In order to solve the above problems, one aspect of the stirring device disclosed herein is a stirring device equipped with a stirring impeller that rotates to stir a stirred fluid contained in a stirring vessel, wherein the ratio L / D of the liquid level height L of the stirred fluid in the stirring vessel in the vertical direction to the vessel diameter D of the stirring vessel in the radial direction is 2 or more, and the stirring impeller has multiple blade portions that are spaced apart in the vertical direction. The blade portions closer to the bottom of the stirring vessel have larger radial blade diameters, and each of the multiple blade portions generates a flow of the stirred fluid that has a vertical component toward the bottom of the stirring vessel.

[0007] In this embodiment, the agitator impellers, which are configured in multiple stages in the height direction to fit a vertically long agitated vessel with an L / D ratio of 2 or more, generate a flow of the agitated fluid with a height component toward the bottom of the agitated vessel. Because the blade diameters of the multiple blades that make up the agitator impeller increase as they approach the bottom of the agitated vessel, the agitated fluid flowing toward the bottom is effectively supplied to the large-diameter blades on the bottom side and agitated. Here, the shape of each blade is arbitrary as long as it can generate a flow of the agitated fluid toward the bottom of the agitated vessel. For example, a general paddle blade can be used. Therefore, the agitated fluid in the agitated vessel can be effectively agitated without using an agitator impeller with a special shape as in Patent Document 1.

[0008] Another aspect of the present disclosure is a stirring method. This method is a stirring method in a stirring device equipped with a stirring impeller that rotates to stir a stirred fluid contained in a stirring vessel, in which the ratio L / D of the liquid level height L of the stirred fluid in the stirring vessel in the vertical direction to the vessel diameter D in the radial direction of the stirring vessel is 2 or greater, and the stirring impeller has multiple blades arranged at intervals in the vertical direction, with the radial blade diameters of the multiple blades increasing as the blades approach the bottom of the stirring vessel. The rotation of each blade generates a flow of the stirred fluid that has a vertical component toward the bottom of the stirring vessel.

[0009] Any combination of the above components, or any conversion of these expressions into methods, devices, systems, recording media, computer programs, etc., are also encompassed within the present disclosure.

[0010] According to the present disclosure, the fluid to be stirred in the stirring tank can be effectively stirred without using stirring blades with special shapes.

[0011] FIG. 1 is a longitudinal cross-sectional view of an agitation device; FIG. 2 is a comparative example of an agitation device; FIG. 3 is a graph comparing the monomer concentration at each height in an agitation tank for a comparative example and an embodiment; FIG. 4 is a flow pattern of a comparative example; FIG. 5 is a flow pattern of an embodiment. The production conditions, aggregate amount, and measured physical strength of nitrile gloves according to Examples 1 to 4 and Comparative Examples 1 to 4 are shown, respectively.

[0012] Hereinafter, with reference to the drawings, a detailed description will be given of a mode for carrying out the present disclosure (hereinafter also referred to as an embodiment). In the description and / or drawings, the same or equivalent components, members, processes, etc. are designated by the same reference numerals, and redundant description will be omitted. The scale and shape of each part shown in the drawings are set for convenience to simplify the description, and should not be interpreted as limiting unless otherwise specified. The embodiment is an example and does not limit the scope of the present disclosure in any way. All features and combinations thereof described in the embodiment are not necessarily essential to the present disclosure.

[0013] FIG. 1 is a longitudinal cross-sectional view of an agitator 1 according to an embodiment of the present disclosure. In this embodiment, the agitator 1 is installed vertically, which corresponds to the up-down, vertical, and height directions in FIG. 1 . The terms up-down, vertical, height, and vertical are used interchangeably, and the terms left-right, horizontal, and horizontal are also used interchangeably. Note that the present disclosure is also applicable to an agitator 1 that is not installed vertically. In such cases, the up-down, vertical, and height directions are different from the vertical direction, and the left-right, horizontal, and horizontal directions are different from the horizontal direction. Furthermore, as described below, the rotation shaft 30 of the agitator 3 is provided in the up-down, vertical, height, and vertical directions, and therefore the up-down, vertical, height, and vertical directions are also referred to as axial directions. Furthermore, the left-right, horizontal, and horizontal directions are also referred to as radial directions, because the left-right, horizontal, and horizontal directions determine the diameter of the agitator vessel 2 and the agitator 3.

[0014] The stirring device 1 includes a stirring tank 2 containing a fluid to be stirred (fluid to be stirred) and a stirring impeller 3 that rotates to stir the fluid in the stirring tank 2. The stirring tank 2 includes a cylindrical straight body portion 21 located at the top and extending in the axial direction, and a bottom portion 22 located below and continuous with the straight body portion 21. The inner peripheral wall or side wall of the straight body portion 21 has a circular cross section when viewed from above (axially), and its diameter D is hereinafter also referred to as the vessel diameter D of the stirring tank 2. Note that the cross section of the straight body portion 21 and / or the stirring tank 2 when viewed from above may have any non-circular shape. In this case, the vessel diameter D of the stirring tank 2 may be the diameter of the inscribed circle of the cross-sectional shape, the diameter of the circumscribed circle of the cross-sectional shape, or an average or intermediate value thereof. At least a portion of the upper portion of the straight body portion 21 is open (not shown) so that the fluid to be stirred can be introduced, and the opening can be closed with a lid or the like while the fluid is being stirred by the stirring impeller 3. The fluid to be stirred may be supplied into the stirring tank 2 from a fluid supply port such as a supply nozzle provided on the side of the barrel portion 21, for example.

[0015] The bottom 22 of the stirring tank 2 is formed in a curved shape that bulges downward from the lower end of the cylindrical body 21. The center of the bottom 22 is formed by the bulging end of the curved shape, forming the lowest part of the stirring tank 2. A drain port that can discharge the fluid in the stirring tank 2 to the outside of the stirring device 1 may be provided at the lowest part of the stirring tank 2. This drain port is configured to be openable and closable by a drain port opening / closing unit such as a valve. A valve or the like controlled to a closed state closes the drain port when the fluid to be stirred is introduced into the stirring tank 2 and retained therein, or when the fluid before discharge is stirred with the stirring blades 3 to promote mixing or chemical reaction or to homogenize the concentration. Furthermore, a valve or the like controlled to an open state opens the drain port when the fluid to be discharged is stirred by the stirring blades 3 as needed after the mixing or chemical reaction is substantially completed and the concentration is homogenized. The stirred fluid may be discharged from an opening, such as an opening at the top of the stirring tank 2 when the lid is open. The stirred fluid may also be discharged from a fluid outlet, such as a discharge nozzle, provided on the side of the cylindrical body 21.

[0016] The horizontal boundary between the approximately cylindrical barrel portion 21 and the curved bottom portion 22 is also referred to as the tangent line TL. Hereinafter, the vertical distance L between the lowest part of the stirred tank 2 (bottom 22) and the surface or liquid level LL of the fluid in the stirred tank 2 is also referred to as the liquid level height or reference height. In this embodiment, the ratio L / D of the liquid level L in the vertical direction of the stirred fluid in the stirred tank 2 to the vessel diameter D in the radial direction of the stirred tank 2 is 2 or greater. Such a vertically elongated stirred tank 2 allows for a large area of ​​the sidewalls that serve as heat dissipation surfaces, making it suitable for stirring the stirred fluid (chemical reaction) that generates a large amount of reaction heat. An example of such a chemical reaction is emulsion polymerization.

[0017] The stirred fluid for emulsion polymerization contains an aqueous medium such as water and a monomer to be emulsion polymerized. In this embodiment, the monomer preferably contains a conjugated diene monomer and a carboxyl group in the polymer chain. Typically, an emulsifier (such as a surfactant) and a polymerization initiator (such as a radical generator) are also added to the stirred fluid. The stirring device 1 according to this embodiment can achieve the desired stirring performance when the specific gravity difference between the component with the highest specific gravity (typically the medium) and the component with the lowest specific gravity (typically the monomer) among the multiple components contained in the stirred fluid before emulsion polymerization is greater than 0.2 and less than 0.4. However, the stirring device 1 according to this embodiment may also be used to stir a stirred fluid outside this specific gravity difference range. The stirring by the rotating stirring blades 3 promotes emulsion polymerization of the monomer in the stirred fluid, resulting in a latex in which polymer particles are dispersed in the medium as the final product.

[0018] The agitator blade 3 is rotatably mounted around a vertical rotation shaft 30 that substantially coincides with the vertical central axis of the agitator tank 2. Although not shown, a rotation drive unit such as a motor that generates rotational power and a rotational power conversion unit such as a transmission or reducer that converts the rotational power into a desired number of rotations (or rotational speed) or torque are provided above the rotation shaft 30. A lower bearing may be provided below the rotation shaft 30.

[0019] A baffle 4 is provided near the inner peripheral wall of the straight body portion 21 in the stirring vessel 2, extending in a substantially axial direction over most of the liquid level height L and projecting in a substantially radial direction toward the central axis of the stirring vessel 2 (or the rotation axis 30 of the stirring blade 3). Although not shown, multiple baffles 4 may be provided along the circumferential direction. The stirred fluid rotated in the circumferential direction by the stirring blade 3 hits the baffle 4, also called a baffle plate, preventing the stirred fluid from rotating together with the stirring blade 3 due to inertia. Note that the baffle 4 must not interfere with the rotation of the stirring blade 3 itself, and is located in a radial range outside the rotation area of ​​the lowest blade portion 35, which has the largest blade diameter among the multiple blade portions 31 to 35 described below.

[0020] The agitator blade 3 includes multiple (five in the example of FIG. 1 ) blade sections 31-35 with different blade diameters, spaced apart in the height direction (axial direction). Each blade section 31-35 is a small agitator blade that is generally linear or generally planar (normal to the rotation shaft 30) extending generally radially from the rotation shaft 30. These blade sections 31-35 can be configured with any type and / or shape of agitator blade, as long as they can achieve at least some of the functions and / or effects described below (particularly, the function described below of directly generating a flow of the agitated fluid having a height component toward the bottom 22 of the agitator vessel 2). In this embodiment, an example is described in which all blade sections 31-35 are inclined paddle blades with one or more agitation surfaces in which the normal direction of the agitation surface is inclined with respect to both the axial direction and the horizontal direction. However, some or all of the multiple blade sections 31-35 may be configured with axial-flow blades, such as hydrofoils.

[0021] The multiple wing portions 31-35 are preferably arranged at approximately equal intervals along the height direction. In particular, to achieve the functions and / or effects of this embodiment described below, the height distance (spacing) between two vertically adjacent wing portions 31 / 32, 32 / 33, 33 / 34, and 34 / 35 is preferably smaller than the blade diameter of the uppermost wing portion 31, and more preferably smaller than the radius (half the blade diameter) of the uppermost wing portion 31. As is clear from a comparison with FIG. 2 (a comparative example (general example) described below), the spacing between the wing portions 31-35 in this embodiment of FIG. 1 is generally shorter than that in the comparative example. Alternatively, the number of wing portions 31-35 in this embodiment of FIG. 1 is generally greater than that in the comparative example. The spacing between the multiple wing portions 31-35 along the height direction may be different from one another.

[0022] The radial blade diameters of the multiple blades 31 to 35 increase as they approach the bottom 22 of the agitation tank 2. Specifically, the blade diameter of the uppermost blade 31, which is farthest from the bottom 22, is smallest, and the blade diameter of the lowermost blade 35, which is closest to the bottom 22, is largest. Furthermore, the blade diameters of the blades 31 to 35 increase gradually or stepwise from the uppermost blade 31 to the lowermost blade 35. The rate of increase in the blade diameter of two vertically adjacent blades 31 / 32, 32 / 33, 33 / 34, and 34 / 35 may be equal or different. For example, to achieve the functions and / or effects of this embodiment described below, the angle θ formed by the line connecting the radial tips of two vertically adjacent blades (e.g., a pair of blades 31 / 32) and the liquid level LL or the horizontal plane is preferably 65 degrees or more and less than 85 degrees, and more preferably 75 degrees or more and less than 85 degrees.

[0023] Furthermore, in order to realize the functions and / or effects of this embodiment described below, the blade diameter of the uppermost blade 31, which is the farthest from the bottom 22 of the stirred tank 2 among the multiple blades 31 to 35, is preferably 30% to less than 55% of the tank diameter D, and more preferably 35% to less than 50% of the tank diameter D. Similarly, in order to realize the functions and / or effects of this embodiment described below, the blade diameter of the lowermost blade 35, which is the closest to the bottom 22 of the stirred tank 2 among the multiple blades 31 to 35, is preferably 50% to less than 80% of the tank diameter D, and more preferably 60% to less than 70% of the tank diameter D. As shown in the figure, the lowermost blade 35 is preferably positioned in the axial direction adjacent to or overlapping with the tangent line TL.

[0024] Each of the blades 31-35 constituting the agitating impeller 3 as described above generates a flow of the agitated fluid having a vertical component (downward component) toward the bottom 22 of the agitating vessel 2 by rotating around the rotation shaft 30. As described above, all of the blades 31-35 in this embodiment are inclined paddle blades with inclined agitating surfaces. Specifically, the normal direction of the agitating surface of each blade 31-35 is neither parallel nor perpendicular to either the axial direction (the vertical direction in FIG. 1 ) or the circumferential direction (the direction perpendicular to the paper surface in FIG. 1 ). In the example of FIG. 1 , the portion of each blade 31-35 extending to the right of the rotation shaft 30 is inclined so that its upper edge is in front of the paper surface and its lower edge is in back of the paper surface. Similarly, the portion of each blade 31-35 extending to the left of the rotation shaft 30 is inclined so that its upper edge is in back of the paper surface and its lower edge is in front of the paper surface. By rotating each of these blades 31 to 35 around the rotation axis 30 in the direction shown in the schematic diagram, a downward flow of the stirred fluid toward the bottom 22 of the stirring tank 2 is generated.

[0025] The flow generated by each of the blades 31-35 may include a radial component (lateral component) in addition to a vertical component, particularly a component radially away from the rotation shaft 30. Therefore, the fluid being stirred by each of the blades 31-35 flows downward while expanding radially around the rotation shaft 30. In this embodiment, the blade diameters of the multiple blades 31-35 constituting the stirring blade 3 become larger the closer they are to the bottom 22 of the stirring tank 2. Therefore, the fluid being stirred flowing toward the bottom 22 is effectively supplied to the large-diameter blades on the bottom 22 side and stirred. Therefore, emulsion polymerization of the monomers in the fluid being stirred is effectively promoted, resulting in a high-quality final product (latex, etc.).

[0026] Figure 2 is a comparative example of the agitator 1. This agitator 1 differs from the agitator 1 according to the present embodiment shown in Figure 1 only in the configuration of the agitator blade 3. Specifically, the spacing in the height direction between the multiple blade portions in the agitator blade 3 in Figure 2 is longer than the spacing in the height direction between the multiple blade portions 31 to 35 in the agitator blade 3 in Figure 1. In addition, the number of blade portions in the agitator blade 3 in Figure 2 (3) is less than the number of blade portions 31 to 35 in the agitator blade 3 in Figure 1 (5). Furthermore, the blade diameters of the multiple blade portions in the agitator blade 3 in Figure 2 are equal to each other.

[0027] FIG. 3 is a graph comparing the monomer concentration at each height in the stirring tank 2 between the comparative example (FIG. 2) and the present embodiment (FIG. 1). Height "a" in this graph is lower than the liquid level LL and higher than the uppermost blade 31 in FIG. 1. Height "k" in this graph is lower than the lowermost blade 35 in FIG. 1 and higher than the lowermost part of the stirring tank 2 (bottom 22). Intermediate heights "b" to "j" are positions equally spaced between the uppermost height "a" and the lowermost height "k." In this comparison, a stirred fluid with a volume ratio of monomer to water (medium) of 4.5:5.5 was used. Therefore, the closer the monomer concentration in the graph is to "0.45," the better the stirring of the monomer in the medium.

[0028] In the comparative example, the monomer concentration is close to the target value of 0.45 at heights "h" to "k" near the bottom of the stirred tank 2, but is significantly lower than the target value of 0.45 at heights "a" to "g" above. Thus, the agitator impeller 3 of the comparative example lacks mixing performance in the upper part of the stirred tank 2 for a stirred fluid containing components with large differences in specific gravity, such as monomer and water (as mentioned above, approximately 0.2 to 0.4). In contrast, the agitator impeller 3 of this embodiment achieves a high level of monomer concentration across the entire height range from "a" to "k." Thus, the agitator impeller 3 of this embodiment can agitate the stirred fluid more effectively than the comparative example, and can improve the uniformity of the concentration of the stirred fluid despite the large liquid level L of the vertically long stirred tank 2.

[0029] 4 and 5 are flow patterns visualized for the comparative example (FIG. 2) and the present embodiment (FIG. 1) of the present invention, showing the flow of the stirred fluid in the stirring vessel 2. In the flow pattern of the comparative example (FIG. 4), the stirred fluid circulates in limited axial regions on the radially outer side (both left and right sides) of each blade. Thus, for stirred fluids containing components with large differences in specific gravity, such as monomers and water, flow partitions are formed between the blades, causing the stirred fluid to circulate locally, resulting in a deterioration in the stirring performance of the stirring vessel 2 as a whole (as shown in FIG. 3, the concentration uniformity of the stirred fluid is reduced). Furthermore, the stirred fluid accumulates in the partitions, making it easier for low-specific-gravity monomers and polymers to adhere to the blades.

[0030] In contrast, in the flow pattern of this embodiment shown in Figure 5, the flow of the stirred fluid is smoothly transferred from the upper blade section to the lower blade section, and the stirred fluid is sequentially stirred from the uppermost blade section 31 to the lowermost blade section 35 (i.e., across almost the entire liquid level L). Local circulation near each blade section, as in the comparative example shown in Figure 4, is significantly reduced, resulting in a flow of stirred fluid that circulates widely between the top and bottom of the vertically elongated stirred tank 2. As a result, the stirred fluid is less likely to stagnate between the blade sections, making it less likely for monomers and polymers to adhere to the blade sections. Experiments have shown that the amount of adhesion to the stirring blade 3 of this embodiment is reduced to approximately 30% of the amount of adhesion to the stirring blade 3 of the comparative example.

[0031] The stirring device 1 according to the present embodiment as described above is suitable for promoting emulsion polymerization and can be used, for example, in the production of emulsion polymerization and other compositions, as follows. In particular, in emulsion copolymerization reactions carried out by copolymerizing monomers with different densities, it is believed that more uniform distribution of the monomers within the reaction vessel significantly affects the uniformity of the composition of the resulting copolymer. Furthermore, the uniformity of the composition of the resulting copolymer can also affect the physical properties of the molded product formed from the polymer.

[0032] [Production of Latex Composition] The latex composition according to the present disclosure may be a latex composition produced using any copolymerizable monomer, as long as it has a conjugated diene monomer as the main monomer and contains a carboxyl group in the polymer chain. A carboxyl group-containing nitrile rubber latex is preferred. The carboxyl group-containing nitrile rubber latex is a latex produced by copolymerizing a conjugated diene monomer, an ethylenically unsaturated nitrile monomer, and a copolymerizable ethylenically unsaturated carboxylic acid monomer.

[0033] [Conjugated diene monomer] The conjugated diene monomer is not particularly limited as long as it has radical polymerization reactivity. Specific examples of the conjugated diene monomer include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene, and chloroprene. These conjugated diene monomers can be used alone or in combination of two or more.

[0034] [Ethylenically unsaturated nitrile monomer] The ethylenically unsaturated nitrile monomer may be any one having both a polymerizable unsaturated bond and a nitrile group in one molecule, and examples thereof include acrylonitrile, methacrylonitrile, fumaronitrile, α-chloroacrylonitrile, α-cyanoethylacrylonitrile, etc. Among these, acrylonitrile and methacrylonitrile are preferred, and acrylonitrile is more preferred.

[0035] [Ethylenically unsaturated carboxylic acid monomer] The ethylenically unsaturated carboxylic acid monomer copolymerizable with the conjugated diene monomer and the ethylenically unsaturated nitrile monomer may be any one having a polymerizable unsaturated bond and a carboxyl group in the molecule, and examples thereof include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, maleic anhydride, citraconic anhydride, etc., and may be in an acid state or a salt state. Among these, acrylic acid and methacrylic acid are preferred.

[0036] [Other Ethylenically Unsaturated Monomers] In addition to the conjugated diene monomer, the ethylenically unsaturated nitrile monomer, and the ethylenically unsaturated carboxylic acid monomer, other ethylenically unsaturated monomers may be used as necessary. For example, ethylenically unsaturated sulfonic acid monomers such as acrylamidopropanesulfonic acid and styrenesulfonic acid; methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, monoethyl itaconate, monobutyl fumarate, monobutyl maleate, dibutyl maleate, dibutyl fumarate, ethyl maleate, mono-2-hydroxypropyl maleate, methoxymethyl (meth)acrylate, ethoxyethyl (meth)acrylate, methoxyethoxyethyl (meth)acrylate, cyanomethyl (meth)acrylate, 2-cyanoethyl (meth)acrylate, 1-cyanopropyl (meth)acrylate, 2-ethyl-6-cyanohexyl (meth)acrylate, 3-cyano (meth)acrylate ethylenically unsaturated carboxylic acid ester monomers such as propyl, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, glycidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, 2-sulfoethyl acrylate, and 2-sulfopropyl methacrylate; ethylenically unsaturated amide monomers such as (meth)acrylamide, N-methylol (meth)acrylamide, N,N-dimethylol (meth)acrylamide, N-methoxymethyl (meth)acrylamide, and N-propoxymethyl (meth)acrylamide; vinyl aromatic monomers such as styrene, alkylstyrene, and vinylnaphthalene; fluoroalkyl vinyl ethers such as fluoroethyl vinyl ether; vinylpyridine; and non-conjugated diene monomers such as vinylnorbornene, dicyclopentadiene, and 1,4-hexadiene.

[0037] [Monomer Ratios in Copolymer] When these monomers are used in combination in the production of the latex composition of the present disclosure, the types and ratios thereof may be appropriately selected depending on the purpose and application. When a conjugated diene monomer, an ethylenically unsaturated nitrile monomer, and other copolymerizable monomers are used in combination, the conjugated diene monomer is usually 30 to 90 wt %, preferably 50 to 78 wt %, the ethylenically unsaturated nitrile monomer is 10 to 50 wt %, preferably 20 to 40 wt %, and the other copolymerizable monomer is 0.1 to 20 wt %, preferably 2 to 10 wt %, based on the total monomers. Furthermore, as the other copolymerizable monomer, an ethylenically unsaturated carboxylic acid monomer is preferred.

[0038] [Emulsifier] The emulsifier used in producing the latex composition of the present disclosure is not particularly limited, but is preferably one that is commonly used in emulsion polymerization. Examples thereof include nonionic emulsifiers such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, polyoxyethylene alkyl esters, and polyoxyethylene sorbitan alkyl esters; fatty acids such as myristic acid, palmitic acid, oleic acid, and linolenic acid and salts thereof, phosphate esters such as isopropyl phosphate and polyoxyethylene alkyl ether phosphate; anionic emulsifiers such as alkyl diphenyl ether disulfonates, disodium lauryl diphenyloxysulfonate, alkyl naphthalene sulfonates, sodium salts of naphthalene sulfonate-formalin condensates, sodium dialkyl sulfosuccinates, alkyl benzene sulfonates, alkyl aryl sulfonates, higher alcohol sulfate ester salts, and alkyl sulfosuccinic acids; and copolymerizable emulsifiers containing a double bond such as sulfoesters of α,β-unsaturated carboxylic acids, sulfate esters of α,β-unsaturated carboxylic acids, and sulfoalkyl aryl ethers. The amount of emulsifier used is not particularly limited, but is 0.1 to 10 parts by weight, preferably 0.5 to 6.0 parts by weight, per 100 parts by weight of the monomer mixture. The emulsifier may be used alone or in combination of two or more kinds. Furthermore, the emulsifier may be used all at once or in portions during the production of the latex composition.

[0039] [Chain Transfer Agent] Examples of chain transfer agents used in producing the latex composition of the present disclosure include mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan, mercaptoethanol, etc., halogenated hydrocarbons such as carbon tetrachloride, methylene chloride, methylene bromide, etc., α-methylstyrene dimer, etc. Mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan, etc. are preferred.

[0040] [Aqueous Medium] Water is typically used as the aqueous medium for producing the latex composition of the present disclosure, and the amount thereof is typically 70 to 250 parts by weight, preferably 80 to 170 parts by weight, per 100 parts by weight of the monomer mixture. If the aqueous medium is less than 70 parts by weight, stability may decrease during the polymerization process. If the aqueous medium is more than 250 parts by weight, post-processing of the resulting latex requires more time and energy, resulting in an inefficient production process of the latex composition.

[0041] [Polymerization Initiator] The polymerization initiator used in producing the latex composition of the present disclosure is not particularly limited, but examples thereof include potassium persulfate, ammonium persulfate, sodium persulfate, perphosphate, hydrogen peroxide, t-butyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, p-menthane hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, diisopropylbenzene hydroperoxide, cumene hydroperoxide, di-t-butyl peroxide, di-α-cumyl peroxide, acetyl peroxide, isobutyryl peroxide, benzoyl peroxide, and azobisisobutyronitrile. These polymerization initiators can be used alone or in combination of two or more. The amount of polymerization initiator used is typically 0.001 to 10 parts by weight per 100 parts by weight of the monomer mixture. Furthermore, a peroxide initiator can be used in combination with a reducing agent as a redox polymerization initiator. The reducing agent is not particularly limited, but examples thereof include compounds having reduced metal ions such as ferrous sulfate and cuprous naphthenate, sulfonates such as sodium methanesulfonate, formaldehyde sulfoxylate salts such as sodium formaldehyde sulfoxylate, 2-hydroxy-2-sulfonatoacetate salts such as disodium salt of 2-hydroxy-2-sulfonatoacetate, 2-hydroxy-2-sulfinatoacetate salts such as disodium salt of 2-hydroxy-2-sulfinatoacetate, amines such as formdimethylaniline, and ascorbic acid. These reducing agents can be used alone or in combination of two or more. There are no particular limitations on the amount of reducing agent used, but the weight ratio to the peroxide (peroxide / reducing agent) is 0.01 to 100, preferably 0.1 to 50.

[0042] [Latex Composition Polymerization Method] The latex composition production method of the present disclosure can be carried out by a conventional polymerization method, and the polymerization reactor may be any of batch, semi-batch, and continuous types. The monomers may be added to the polymerization reactor all at once, continuously or intermittently as the polymerization reaction progresses, or a portion of the monomers are added and reacted until a specific conversion rate is reached, followed by continuous or continuous addition of the remaining monomers. Any of these addition methods may be employed. The monomers to be added may be premixed or added separately. When various monomers are mixed, the mixing ratio may be constant or variable. The polymerization temperature during the polymerization reaction is not particularly limited, but is typically 0 to 100°C, preferably 5 to 70°C. When a predetermined polymerization conversion rate is reached, the polymerization reaction is terminated by cooling the polymerization system or adding a polymerization terminator. The polymerization conversion rate when the polymerization reaction is terminated is usually preferably 90% or more, more preferably 93% or more.

[0043] [Polymerization Terminator] The polymerization terminator used in producing the latex composition of the present disclosure is not particularly limited, and examples thereof include nitrites such as sodium nitrite, potassium nitrite, and ammonium nitrite, ascorbic acid, citric acid, hydroxylamine, hydroxyamine sulfate, diethylhydroxylamine, hydroxyamine sulfonic acid and alkali metal salts thereof, 2,2,6,6-tetramethylpiperidinooxyl compounds such as 4-benzoyloxy-2,2,6,6-tetramethylpiperidinooxyl, sodium dimethyldithiocarbamate, dimethyldithiocarbamate, hydroquinone derivatives, catechol derivatives, resorcinol derivatives, aromatic hydroxydithiocarboxylic acids such as hydroxydimethylbenzenedithiocarboxylic acid, hydroxydiethylbenzenedithiocarboxylic acid, and hydroxydibutylbenzenedithiocarboxylic acid, and alkali metal salts thereof. The polymerization terminator may be added after or simultaneously with the addition of an inorganic base aqueous solution such as a sodium hydroxide aqueous solution, a potassium hydroxide aqueous solution, or aqueous ammonia. The amount of the polymerization terminator used is usually 0.01 to 5 parts by weight, preferably 0.03 to 2 parts by weight, based on 100 parts by weight of the monomer mixture.

[0044] [Preparation of Latex Composition] After terminating the latex polymerization reaction, the desired latex composition is produced by removing unreacted monomers, adjusting the solids concentration and pH, and adding surfactants, antioxidants, preservatives, antibacterial agents, etc., as needed. In the production of the latex composition of the present disclosure, secondary polymerization materials such as oxygen scavengers, dispersants, surfactants, chelating agents, molecular weight regulators, particle size regulators, antioxidants, preservatives, etc. may also be used as needed. The secondary polymerization material components may be organic or inorganic compounds.

[0045] [Dip Molding Compounding Agents] The dip molding composition of the present disclosure is produced by adding dip molding compounding agents to a latex composition. The dip molding compounding agents preferably contain a crosslinking agent and a vulcanizing agent capable of crosslinking between polymers, and may also contain zinc oxide, sulfur, a vulcanization accelerator, and other components. Vulcanizing agents commonly used in dip molding can be used, including, for example, sulfur such as powdered sulfur, sulfur flowers, precipitated sulfur, colloidal sulfur, surface-treated sulfur, and insoluble sulfur; and polyamines such as hexamethylenediamine, triethylenetetramine, and tetraethylenepentamine; with sulfur being particularly preferred. The amount of sulfur vulcanizing agent used is preferably 0.1 to 5 parts by weight, more preferably 0.3 to 2 parts by weight, per 100 parts by weight of the latex solids. As the vulcanization accelerator, those usually used in dip molding can be used, for example, dithiocarbamic acids such as diethyldithiocarbamic acid, dibutyldithiocarbamic acid, di-2-ethylhexyldithiocarbamic acid, dicyclohexyldithiocarbamic acid, diphenyldithiocarbamic acid, dibenzyldithiocarbamic acid, and zinc salts thereof; 2-mercaptobenzothiazole, 2-mercaptobenzothiazole zinc, 2-mercapto Examples of suitable vulcanization accelerators include thiazoline, dibenzothiazyl disulfide, 2-(2,4-dinitrophenylthio)benzothiazole, 2-(N,N-diethylthiocarbylthio)benzothiazole, 2-(2,6-dimethyl-4-morpholinothio)benzothiazole, 2-(4'-morpholinodithio)benzothiazole, 4-morpholinyl-2-benzothiazyl disulfide, and 1,3-bis(2-benzothiazyl mercaptomethyl)urea. Among these, zinc dibutyldithiocarbamate, 2-mercaptobenzothiazole, and zinc 2-mercaptobenzothiazole are preferred. These vulcanization accelerators can be used alone or in combination of two or more. The amount of vulcanization accelerator used is 0.1 to 5 parts by weight, preferably 0.3 to 2 parts by weight, per 100 parts by weight of the latex solids. Zinc oxide is commonly used for its vulcanization-accelerating and crosslinking effects. Metal oxides other than zinc oxide may also be used, and oxides of divalent metals or trivalent metals may also be used.Examples of the metal oxide include magnesium oxide, aluminum oxide, barium oxide, vanadium oxide, chromium oxide, titanium oxide, lead oxide, and iron oxide. The amount of zinc oxide used is 5 parts by weight or less, preferably 2 parts by weight or less, based on 100 parts by weight of the solid content of the latex. These metal oxide compounds may be used as a mixture with polyethylene glycol and a hydroxide salt.

[0046] [Production of Compound Composition] The compound composition is produced by mixing, under stirring, the latex composition produced in the polymerization reaction step with, as needed, a pH adjuster, surfactant, water, crosslinking agent, pigment, antioxidant, preservative, wax, inorganic filler, etc. When producing dip-molded products such as gloves, a compound composition is produced using a carboxyl group-containing nitrile rubber latex as the latex composition, and then a processing step is carried out using a dip-processing mold. A common method for generating a crosslinked structure in a carboxyl group-containing nitrile rubber latex is to use a combination of sulfur or a sulfur-containing crosslinking agent, a vulcanization accelerator that accelerates the crosslinking reaction, and a metal compound containing a polyvalent metal such as zinc oxide. After production, the compound composition is left to age under stirring. The solids concentration of the dip-molding composition of the present disclosure is preferably 10 to 40 wt %, more preferably 15 to 30 wt %. The pH of the dip-molding composition is 8.5 to 12, preferably 9 to 11.

[0047] [Manufacturing of Dip-Molded Products] The production of dip-molded products practiced in the present disclosure includes a dip-molding process in which a compound composition is coagulated onto a dip-molding mold to form a film, and a crosslinking process in which a crosslinked structure is formed in the latex composition. Dip-molding methods include, for example, direct immersion, coagulation immersion, electrical immersion, and thermal immersion. Any of these methods may be used. However, direct immersion and coagulation immersion are preferred because they facilitate the production of dip-molded products with uniform thickness. The coagulation immersion method involves immersing a dip-molding mold in a coagulant solution to adhere the coagulant to the mold surface, and then immersing the mold in the compound composition to form a dip-molded layer on the mold surface. The dip-molding and crosslinking processes may be performed simultaneously, or one may be performed before the other. The coagulant used in the coagulation immersion method is generally provided as a mixture of coagulant components, solvent, surfactant, wetting agent, inorganic filler, mold release agent, etc. Examples of coagulant components include metal halides such as barium chloride, calcium chloride, magnesium chloride, aluminum chloride, and zinc chloride; nitrates such as barium nitrate, calcium nitrate, and zinc nitrate; acetates such as barium acetate, calcium acetate, and zinc acetate; sulfates such as calcium sulfate, magnesium sulfate, and aluminum sulfate; and acids such as acetic acid, sulfuric acid, hydrochloric acid, and nitric acid. These compounds can be used alone or in combination, with calcium nitrate and calcium chloride being more preferred. The solvent is selected from water, alcohol, acids, and the like as needed. Surfactants are used to uniformly adhere the coagulation liquid to the mold surface and facilitate demolding, and include nonionic surfactants, metal soaps, and other compounds. Metal soaps include calcium stearate, ammonium stearate, and zinc stearate. Metal oxides, calcium carbonate, talc, and inorganic fillers may also be used as needed.The crosslinking process is a process for generating a crosslinked structure in the dip-molded product, and generally includes aging, which is carried out by adding stabilizers, reactants, crosslinking agents, etc. when the polymer exists as a latex composition, or by carrying out heat treatment, stirring, aging, filtration, etc., or a crosslinking process carried out in parallel with the pre-vulcanization process and the dip-molding process, or a crosslinking process carried out after the dip-molding process, and the process is introduced depending on the required performance of the dip-molded product. An example of a process for producing a dip-molded product from a compound composition is shown below.

[0048] 1) A process of washing the molding die and drying and preheating it at 50-100°C. 2) A process of immersing the molding die in a coagulant solution containing calcium ions, etc., then removing and drying it, and then adhering the coagulant to the molding die surface and drying it. 3) A process of immersing the molding die to which the coagulant was attached in (1) in a compound composition, then removing it and gelling the compound composition. 4) A process of leaching the dip-molded product with water or warm water at 30-80°C to remove impurities and unwanted substances. 5) A pre-curing process of heating the molded product at a temperature of 60-150°C for about 1-120 minutes to promote drying of the dip-molded product and a curing process of promoting film formation and crosslinking reaction of the dip-molded product. 6) A process of performing an anti-blocking treatment on the dip-molded product, if necessary. 7) A process of removing the dip-molded product from the molding die. In addition, the steps 4-7) may be interchanged as necessary.

[0049] Anti-blocking treatments include immersion in an aqueous solution of sodium hypochlorite and hydrochloric acid or a chlorination treatment in a chlorine gas chamber, a polymer coating method in which a polymer having anti-blocking properties is applied to the molded product, and a slurry method in which the product is immersed in an aqueous solution containing a lubricant component. Any method may be used. The treatment may also be performed after the dip-molded product is released from the mold. The properties of the resulting dip-molded product are evaluated after the molded product is released from the mold and subjected to temperature and humidity control for at least one day. In implementing the present disclosure, properties such as the tensile strength at break, elongation at break, and stress at 300% elongation, which is an index of flexibility, of the molded product are particularly important.

[0050] [Evaluation of Dip-Molded Product] (Example 1) After the inside of a pressure-resistant reaction vessel having the stirring device 1 according to the present embodiment shown in FIG. 1 was replaced with nitrogen, 67.5 parts of 1,3-butadiene, 27 parts of acrylonitrile, 5.5 parts of methacrylic acid, 0.6 parts of a polymerization regulator (TDM: t-dodecyl mercaptan), 115 parts of ion-exchanged water, 3 parts of an anionic emulsifier (SDBS: sodium dodecylbenzenesulfonate), 0.5 parts of a dispersant (Demol N manufactured by Kao Corporation), an oxygen scavenger (sodium dithionite), 0.1 parts of a chelating agent EDTA (Chilest 400G: manufactured by Chelest Chemical Co., Ltd.), a particle size modifier (potassium pyrophosphate), 0.005 parts of p-menthane hydroperoxide (PMHP) (manufactured by NOF Corporation; Permenta H) and (SFS: sodium formaldehyde sulfoxylate) were added as a redox polymerization initiator. 0.02 parts), and 0.005 parts of ferrous sulfate were added, and the polymerization temperature was maintained at 25°C under stirring for 20 hours. The monomer concentration was calculated by the weight ratio of the total polymerizable monomers to the total weight of the components charged in the reaction vessel. After confirming that the polymerization conversion rate was 95% or higher, the polymerization reaction was terminated by adding a pH adjuster and a polymerization terminator. Unreacted monomers were removed from the resulting latex under reduced pressure, and the pH and concentration of the copolymer latex were adjusted with aqueous ammonia to a solids concentration of 45% and a pH of 8.3. 0.5 parts by solids of an aqueous dispersion of a butylated reaction product of p-cresol and dicyclopentadiene (e.g., Bostex 362 manufactured by AKRON DISPERSIONS) was added as an antioxidant to 100 parts by weight of the latex to obtain a copolymer latex composition.

[0051] The amount of the aggregates deposited in the reaction vessel where the polymerization reaction was carried out was determined as a weight ratio to the total amount of polymer produced in the polymerization reaction. The total amount of the aggregates dispersed in the latex composition was removed by filtration through a 200-mesh wire screen, and the weight ratio was determined as a weight ratio to the total solid content of the latex composition.

[0052] To the resulting latex composition, a 3% aqueous potassium hydroxide solution and soft water were added under stirring to adjust the solids concentration to 17-20% and the pH to 9.5-10. Subsequently, 1.5 parts by weight of a titanium oxide dispersion, 1.1 parts by weight of a zinc oxide dispersion (manufactured by Aquaspersion), 1.1 parts by weight of a sulfur dispersion, and 0.7 parts of a vulcanization accelerator ZDEC dispersion were added. After stirring at room temperature for 12 hours, the aggregates were removed using a 200-mesh wire screen. After removing air bubbles, the temperature of the latex compounded composition was adjusted to 20-40°C. The amount of aggregates removed from the latex compounded composition was calculated as a weight ratio to the total compounded mass.

[0053] Next, the washed and heated ceramic hand mold was immersed in a coagulant consisting of a 14% by weight aqueous solution of calcium nitrate and 1.5% calcium stearate, and then dried at 70°C for 3 minutes to allow the coagulant to adhere. The hand mold was immersed in the latex-blended composition for 30-60 seconds, then removed and heated at 80°C for 1 minute to gel the latex-blended composition onto the mold, producing a thin film. The hand mold was then immersed in warm water at 60-70°C for 3 minutes for leaching, and then placed in a test oven and heated at 70°C for 5 minutes. Without removing it from the oven, it was then heated at 130°C for 20 minutes.

[0054] After cooling the surface of the mold to 40°C, the mold was immersed for 40 seconds in a chlorinated bath containing sodium hypochlorite and hydrochloric acid adjusted to an active chlorine concentration of 900-1000 ppm. The mold was then rinsed with water, washed with a 0.4% aqueous sodium sulfate solution, and then dried at 100°C for 5 minutes. After sufficiently cooling the mold at room temperature, the thin film was removed from the mold to produce nitrile gloves. The nitrile gloves were then conditioned at 25°C and 55% RH for 24 hours, after which their physical strength was measured according to ASTM D412.

[0055] The dip-molded nitrile gloves were punched out to prepare test specimens using a Die C manufactured by Dumbbell Co., Ltd. The test specimens were pulled at a pulling rate of 500 mm / min, and the stress at 300% elongation, strength at break, and elongation at break were measured.

[0056] (Example 2) Using a reaction vessel having the same stirring device as described in Example 1, a latex composition was prepared by increasing the number of parts of acrylonitrile monomer used, and a nitrile glove was prepared in the same manner as in Example 1 and evaluated.

[0057] Example 3 Using a reaction vessel having the same stirring device as in Example 1, nitrile gloves were prepared in the same manner as in Example 1 except that the stirring rotation speed was reduced to 130 rpm, and evaluation was carried out.

[0058] Example 4 The same polymerization reaction as in Example 2 was carried out under the condition that the stirring rotation speed was reduced to 130 rpm, and nitrile gloves were produced and evaluated.

[0059] (Comparative Example 1) A latex composition was prepared in the same manner as in Example 1 using a pressure-resistant reaction vessel having a stirring device 1 according to a comparative example shown in Fig. 2 , and then a nitrile glove was prepared through the same steps as in Example 1 and evaluated.

[0060] (Comparative Example 2) Using the same reaction vessel having a stirring device as in Comparative Example 1, a latex composition was prepared by increasing the number of parts of acrylonitrile monomer used, and a nitrile glove was prepared in the same manner as in Example 1 and evaluated.

[0061] Comparative Example 3 Using a reaction vessel having the same stirring device as in Comparative Example 1, nitrile gloves were prepared in the same manner as in Example 1 except that the stirring rotation speed was reduced to 130 rpm, and evaluation was carried out.

[0062] Comparative Example 4 Using a reaction vessel having the same stirring device as in Comparative Example 2, nitrile gloves were prepared in the same manner as in Example 1 under the condition that the stirring rotation speed was reduced to 130 rpm, and evaluation was carried out.

[0063] The production conditions, amount of aggregates, and measured physical strength of the nitrile gloves according to Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Figure 6. In Examples 1 to 4, the amount of aggregates was smaller than in Comparative Examples 1 to 4 because the stirred fluid was able to be stirred effectively. As a result, it was confirmed that the dip-molded products produced in Examples 1 to 4 have better physical strength than Comparative Examples 1 to 4.

[0064] The present disclosure has been described above based on the embodiments. Various modifications are possible to the combinations of the components and processes in the exemplary embodiments, and it will be obvious to those skilled in the art that such modifications are included within the scope of the present disclosure.

[0065] The configuration, operation, and function of each device and method described in the embodiments can be realized by hardware resources, software resources, or a combination of hardware and software resources. Examples of hardware resources include processors, ROM, RAM, and various integrated circuits. Examples of software resources include operating systems, applications, and other programs.

[0066] The present disclosure relates to a stirring device and the like.

[0067] 1 Stirring device, 2 Stirring tank, 3 Stirring blade, 21 Straight body portion, 22 Bottom portion, 30 Rotating shaft, 31 to 35 Blade portion.

Claims

1. A stirring device comprising a stirring blade for stirring a fluid to be stirred accommodated in a stirring tank by rotation, wherein a ratio L / D of a liquid level height L in a height direction of the fluid to be stirred in the stirring tank to a tank diameter D in a radial direction of the stirring tank is 2 or more, the stirring blade includes a plurality of blade portions arranged apart from each other in the height direction, a blade diameter in the radial direction of the plurality of blade portions is larger for a blade portion closer to the bottom of the stirring tank, and each of the plurality of blade portions generates a flow of the fluid to be stirred having a height direction component directed toward the bottom of the stirring tank.

2. The stirring device according to claim 1, wherein the stirring blade includes three or more of the blade portions arranged apart from each other in the height direction.

3. The stirring device according to claim 1 or 2, wherein the plurality of blade portions are each constituted by inclined paddle blades having different blade diameters.

4. The stirring device according to claim 1 or 2, wherein the fluid to be stirred includes a monomer having a conjugated diene monomer and containing a carboxyl group in a polymer chain, and an aqueous medium.

5. The stirring device according to claim 4, wherein a specific gravity difference between the monomer contained in the fluid to be stirred and the aqueous medium is greater than 0.2 and less than 0.

4.

6. The stirring device according to claim 1 or 2, wherein each of the blade portions generates a flow of the fluid to be stirred having a height direction component directed toward the bottom of the stirring tank by rotation.

7. The stirring device according to claim 1 or 2, wherein a blade diameter of a blade portion closest to the bottom of the stirring tank among the plurality of blade portions is 50% or more and less than 80% of the tank diameter D.

8. The stirring device according to claim 1 or 2, wherein a blade diameter of a blade portion farthest from the bottom of the stirring tank among the plurality of blade portions is 30% or more and less than 55% of the tank diameter D.

9. The stirring device according to claim 1 or 2, wherein a distance in the height direction between two adjacent blade portions in the height direction is smaller than a blade diameter of a blade portion farthest from the bottom of the stirring tank.

10. The stirring device according to claim 1 or 2, for two adjacent blade portions in the height direction, an angle formed by a straight line connecting their radial tips and a horizontal plane is 65 degrees or more and less than 85 degrees.

11. A stirring method in a stirring device comprising a stirring blade for stirring a fluid to be stirred accommodated in a stirring tank by rotation, wherein a ratio L / D of a liquid level height L in a height direction of the fluid to be stirred in the stirring tank to a tank diameter D in a radial direction of the stirring tank is 2 or more, the stirring blade includes a plurality of blade portions arranged apart from each other in the height direction, and the radial blade diameters of the plurality of blade portions are larger as they are closer to the bottom of the stirring tank, and a flow of the fluid to be stirred having a height direction component toward the bottom of the stirring tank is generated by rotation of each of the blade portions.

12. The stirring method according to claim 11, wherein the fluid to be stirred includes a monomer having a conjugated diene monomer and containing a carboxyl group in a polymer chain, and an aqueous medium.

13. A polymer latex composition having a structural unit (a) derived from the conjugated diene monomer and a structural unit (b) derived from an ethylenically unsaturated carboxylic acid monomer, which is produced by using the stirring method according to claim 12, and a dip molding composition containing the polymer latex composition.

14. The polymer included in the polymer latex composition has a structural unit (a) derived from the conjugated diene monomer, a structural unit (b) derived from the ethylenically unsaturated carboxylic acid monomer, and a structural unit (c) derived from an ethylenically unsaturated nitrile monomer, and the dip molding composition according to claim 13 containing the polymer latex composition.

15. The dip molding composition according to claim 14, wherein the content ratios of the structural unit (a) derived from the conjugated diene monomer, the structural unit (b) derived from the ethylenically unsaturated carboxylic acid monomer, and the structural unit (c) derived from the ethylenically unsaturated nitrile monomer are 50 to 78 / 2 to 10 / 20 to 40 (mass%).

16. The dip molding composition according to any one of claims 13 to 15, wherein, with respect to 100 mass% of the solid content of the polymer latex composition, the content ratio of zinc oxide is 3 mass% or less, the content ratio of sulfur is 2 mass% or less, and the content ratio of a vulcanization accelerator is 2 mass% or less.

17. A dip molded article formed by molding the dip molding composition according to any one of claims 13 to 15.

18. The dip-molded article according to claim 17, wherein the dip-molded article is a glove.

Images