Dip-molded product, chloroprene polymer, and method for producing dip-molded product

Abstract

The purpose of the present invention is to provide a dip-molded article including a chloroprene-based polymer, the dip-molded article having sufficient tensile strength at break and excellent texture of a dip-molded object (film), and exhibiting excellent feeling of wearing when made into a glove. The present invention provides a dip-molded article including a chloroprene-based polymer, the dip-molded article having a storage modulus E' of 3.2 MPa or less and a loss modulus E" of 0.37 MPa or less in the 10 Hz frequency region, as obtained from tension-type dynamic viscoelasticity measurement based on a non-resonant forced vibration method under the conditions of static tension of 5 gf, temperature of 25°C, strain of 0.75%, and amplitude of 0.15 mm.

Description

[Technical Field]

[0001] The present invention relates to a dip-molded product of a chloroprene polymer, a method for producing a chloroprene polymer and a dip-molded product. More specifically, the present invention relates to a dip-molded product obtained using a chloroprene polymer latex composition containing a chloroprene polymer. [Background technology]

[0002] Chloroprene polymers are known as materials for dip-molded products such as medical surgical gloves, medical examination gloves, industrial gloves, balloons, catheters, and rubber boots.

[0003] Various techniques have been proposed for improving the flexibility of chloroprene polymers by using chloroprene polymer latexes for dip-molded products and for dip-molded products of chloroprene polymers. Patent Document 1 describes a polychloroprene latex with a pH of 7 to 14 for use in dip-molded products, which contains 100 parts by mass of modified polychloroprene obtained by copolymerizing chloroprene and methacrylic acid, 90 to 150 parts by mass of water, 1 to 5 parts by mass of an emulsifier, and 0.5 to 2.5 parts by mass of potassium ions. Patent Document 2 describes a mercaptan-modified polychloroprene latex for use in dip-molded products, which is obtained by copolymerizing chloroprene and 2,3-dichloro-1,3-butadiene, and in which the peak areas (A) at 126.2 to 127.6 ppm, (B) at 122.0 to 126.2 ppm, and (C) at 129.9 to 130.3 ppm in the C-solid-state NMR spectrum of the polychloroprene are within the ranges shown by the following general formula (I). Patent Document 3 describes a chloroprene polymer latex for use in dip-molded products, which contains high-molecular-weight and low-molecular-weight components, thereby achieving both excellent flexibility and mechanical properties in the vulcanized rubber produced by dip molding. Patent Document 4 describes a chloroprene polymer latex that exhibits excellent flexibility and mechanical properties even under mild vulcanization conditions, which is obtained by copolymerizing chloroprene monomer with isoprene monomer, a raw material for isoprene rubber. Patent Document 5 describes a dip-molded product of an isoprene / chloroprene polymer that exhibits excellent flexibility without containing a diphenylguanidine vulcanization accelerator by mixing an isoprene polymer latex with a chloroprene polymer latex. Patent Document 6 describes a dip-molded product that exhibits excellent mechanical properties by mixing a nitrile-butadiene polymer (NBR) latex or an isoprene polymer latex with a chloroprene polymer latex as a base.

[0004]

number

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-114342 [Patent Document 2] International Publication No. 2019 / 009038 [Patent Document 3] Japanese Patent Application Publication No. 2019-143002 [Patent Document 4] International Publication No. 2021-132460 [Patent Document 5] Special Publication No. 2017-508840 [Patent Document 6] Japanese Patent Publication No. 2020-189963 Summary of the Invention [Problem to be solved by the invention]

[0006] Dip-molded products containing chloroprene polymers have been widely used in applications such as gloves, balloons, boots, catheters, etc. However, particularly in medical rubber glove applications, there is a tendency for dip-molded products to be required to have excellent mechanical properties similar to those of dip-molded products obtained using natural rubber or polyisoprene, and there is a need for the development of dip-molded products containing chloroprene polymers that have improved texture of dip-molded products (dip-molded film) and improved wearing comfort (fit) when made into gloves.

[0007] Therefore, an object of the present invention is to provide a dip-molded product containing a chloroprene polymer, which has sufficient tensile strength at break and has an excellent texture when made into a glove, and which provides an excellent wearing comfort when made into a glove. [Means for solving the problem]

[0008] That is, the present invention provides a dip-molded article containing a chloroprene polymer, which has a storage modulus E' of 3.2 MPa or less and a loss modulus E" of 0.37 MPa or less in a frequency range of 10 Hz, as measured by tensile dynamic viscoelasticity measurement in accordance with a non-resonant forced vibration method under conditions of a static tension of 5 gf, a temperature of 25°C, a strain of 0.75%, and an amplitude of 0.15 mm.

[0009] Various embodiments of the present invention will be described below as examples, and the embodiments shown below can be combined with each other. Preferably, the chloroprene-based polymer contains monomer units derived from 2,3-dichloro-1,3-butadiene. Preferably, when the dip-molded product is dissolved in tetrahydrofuran and the soluble matter is measured by gel permeation chromatography, at least a peak corresponding to a weight-average molecular weight of 3,000 to 80,000 is detected. Preferably, the dip-molded product contains at least a metal oxide. Preferably, the dip-molded article is an industrial or general household glove, a medical glove, a balloon, a catheter or a boot.

[0010] According to another aspect of the present invention, there is provided a chloroprene-based polymer, the storage modulus E' of the chloroprene polymer immersion-molded product in a frequency range of 10 Hz is 3.2 MPa or less and the loss modulus E" is 0.37 MPa or less, as measured by a tensile dynamic viscoelasticity measurement method under conditions of a static tension of 5 gf, a temperature of 25°C, a strain of 0.75%, and an amplitude of 0.15 mm in accordance with a non-resonant forced vibration method, The dip-molded product is obtained by molding a chloroprene polymer latex composition containing the chloroprene polymer by a dip coagulation method, and then subjecting the resulting product to a heat drying treatment at 150°C for 60 minutes, thereby providing a chloroprene polymer.

[0011] According to another aspect of the present invention, there is provided a method for producing a dip-molded product containing a chloroprene polymer, the method comprising: a molding step of molding a chloroprene polymer latex composition containing a chloroprene polymer using a calcium-based coagulation liquid by a dip coagulation method to obtain a dip-molded product; and a drying step of subjecting the obtained dip-molded product to a thermal drying treatment to obtain a dip-molded product.

[0012] In the present invention, "JIS" means Japanese Industrial Standards. [Effects of the Invention]

[0013] According to the present invention, there is provided a dip-molded product containing a chloroprene polymer, which has sufficient tensile strength at break, and which has excellent texture as a dip-molded product (film) and excellent wearing comfort when made into a glove. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the preferred embodiments. However, the present invention is not limited to the preferred embodiments described below.

[0015] 1. Chloroprene polymers First, a chloroprene polymer according to one embodiment of the present invention will be described.

[0016] The chloroprene polymer described in this embodiment is a polymer containing monomer units derived from 2-chloro-1,3-butadiene (hereinafter also referred to as chloroprene). Furthermore, the chloroprene polymer according to one embodiment of the present invention may be a copolymer of chloroprene and another monomer copolymerizable with chloroprene. Examples of the other monomer include 1-chloro-1,3-butadiene, 2,3-dichloro-1,3-butadiene, isoprene, styrene, methacrylic acid, acrylonitrile, and sulfur. Two or more of these may be used in combination. The chloroprene polymer according to one embodiment of the present invention preferably contains monomer units derived from 2,3-dichloro-1,3-butadiene. The chloroprene polymer according to one embodiment of the present invention may be sulfur-free, or the chloroprene polymer according to one embodiment of the present invention may be free of an -SS- structure due to sulfur in the main chain.

[0017] The chloroprene polymer according to one embodiment of the present invention may be obtained by blending two or more different chloroprene polymers. The chloroprene polymer preferably contains at least one selected from the group consisting of a homopolymer of chloroprene (2-chloro-1,3-butadiene), a copolymer of chloroprene and 1-chloro-1,3-butadiene, a copolymer of chloroprene and 2,3-dichloro-1,3-butadiene, and a copolymer of chloroprene, 1-chloro-1,3-butadiene, and 2,3-dichloro-1,3-butadiene, and more preferably contains at least one of a homopolymer of chloroprene and a copolymer of chloroprene and 2,3-dichloro-1,3-butadiene.

[0018] A chloroprene polymer according to one embodiment of the present invention may contain 50 to 100 mass% of chloroprene-derived monomer units, preferably 70 to 100 mass%, of chloroprene-derived monomer units, based on 100 mass% of the chloroprene polymer contained in the chloroprene polymer latex composition. The content of the chloroprene-derived monomer units may be, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100 mass%, or may be within a range between any two of the values ​​exemplified here.

[0019] A chloroprene polymer according to one embodiment of the present invention may contain 0 to 30 mass% of monomer units derived from 2,3-dichloro-1,3-butadiene, relative to 100 mass% of the chloroprene polymer contained in the chloroprene polymer latex composition. The content of the monomer units derived from 2,3-dichloro-1,3-butadiene is, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 mass%, and may be within a range between any two of the values ​​exemplified here.

[0020] A chloroprene polymer according to one embodiment of the present invention may contain monomer units derived from chloroprene and monomer units derived from 2,3-dichloro-1,3-butadiene. In this case, the chloroprene polymer preferably contains 0 to 30 mass%, more preferably 5 to 25 mass%, of the monomer units derived from 2,3-dichloro-1,3-butadiene, when the total of the monomer units derived from chloroprene and the monomer units derived from 2,3-dichloro-1,3-butadiene contained in the chloroprene polymer is taken as 100 mass%.

[0021] When the chloroprene polymer is a mixture of two or more different chloroprene polymers, the content of each monomer unit means the total amount of each monomer unit in all chloroprene polymers contained in the chloroprene polymer latex composition.

[0022] In a chloroprene polymer according to one embodiment of the present invention, when the chloroprene polymer contained in the chloroprene polymer latex composition is taken as 100% by mass, the content of the sulfur-modified chloroprene polymer contained in the chloroprene polymer latex composition is preferably 20% by mass or less. The content of the sulfur-modified chloroprene polymer is, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20% by mass, and may be within a range between any two of the values ​​exemplified here. The chloroprene polymer according to one embodiment of the present invention may not contain a sulfur-modified chloroprene polymer.

[0023] In the chloroprene polymer according to one embodiment of the present invention, a peak having a weight-average molecular weight of 3,000 to 80,000 is preferably detected in the molecular weight distribution obtained by measuring a tetrahydrofuran-soluble sol fraction of the chloroprene polymer by gel permeation chromatography. The peak position of the peak detected in the weight-average molecular weight range of 3,000 to 80,000 is, for example, 3,000, 4,000, 5,000, 6,000, 7,000, 8,000, 9,000, 10,000, 11,000, 12,000, 13,000, 14,000, 15,000, 16,000, 17,000, 18,000, 19,000, 20,000, 21,000, 22,000, 23,000, 24,000, 25,000, 26,000, 27,000, 28,000, 29,000, 30,000, 31,000, 32,000, 33,000, 34,000, 35,000, 36,000, 37,000, 38,000, 39,000, 40,000, 41,000, 42,000, 43,000, 44,000, 45,000, 46,000, 47,000, 48,000, 49,000, 50,000, 51,000, 52,000, 53,0 00, 20,000, 21,000, 22,000, 23,000, 24,000, 25,000, 26,000, 27,000, 28,000, 29,000, 30,000, 35,000, 40,000, 50,000, 60,000, 70,000, 80,000, and may be within a range between any two of the numerical values ​​exemplified here. The chloroprene polymer according to one embodiment of the present invention can be a mixture of two or more different chloroprene polymers, and preferably contains a chloroprene polymer having a weight-average molecular weight of 3,000 to 80,000.

[0024] A chloroprene polymer according to one embodiment of the present invention may further include a chloroprene polymer having a weight-average molecular weight of 500,000 to 1,500,000. That is, in the chloroprene polymer according to one embodiment of the present invention, a peak corresponding to a weight-average molecular weight of 500,000 to 1,500,000 may be detected in the molecular weight distribution obtained by measuring a tetrahydrofuran-soluble sol fraction of the chloroprene polymer by gel permeation chromatography. The position of the peak detected in the weight-average molecular weight range of 500,000 to 1,500,000 may be, for example, 500,000, 600,000, 700,000, 800,000, 900,000, 1,000,000, 1,200,000, 1,300,000, or 1,500,000, or may be within a range between any two of the values ​​exemplified here.

[0025] The molecular weight distribution of the tetrahydrofuran-soluble sol fraction of a chloroprene polymer can be obtained by measuring the weight-average molecular weight by gel permeation chromatography (GPC). The GPC measurement conditions can be as described in the Examples. The weight-average molecular weight of a chloroprene polymer can be controlled by adjusting the type and amount of chain transfer agent, polymerization temperature, polymerization time, polymerization conversion rate, etc., during the polymerization of each chloroprene polymer. Furthermore, as described below, the storage modulus E′, loss modulus E″, and tensile strength at break can be adjusted by adjusting the weight-average molecular weight of the chloroprene polymer or the blending ratio of chloroprene polymers having different weight-average molecular weights.

[0026] In a chloroprene polymer according to one embodiment of the present invention, a peak corresponding to a weight-average molecular weight of 3,000 to 80,000 and a peak corresponding to a weight-average molecular weight of 500,000 to 1,000,000 are preferably detected in the molecular weight distribution obtained by measuring a tetrahydrofuran-soluble sol fraction of the chloroprene polymer by gel permeation chromatography. That is, the chloroprene polymer according to one embodiment of the present invention preferably contains a chloroprene polymer having a weight-average molecular weight of 3,000 to 80,000 and a chloroprene polymer having a weight-average molecular weight of 500,000 to 1,500,000.

[0027] The chloroprene polymer according to one embodiment of the present invention preferably contains 5 to 40 mass% of a chloroprene polymer having a weight-average molecular weight of 3,000 to 80,000, based on 100 mass% of the chloroprene polymer. The chloroprene polymer according to one embodiment of the present invention may contain, for example, 5, 10, 15, 20, 25, 30, 35, or 40 mass% of a chloroprene polymer having a weight-average molecular weight of 5,000 to 50,000, based on 100 mass% of the chloroprene polymer, and may be within a range between any two of the numerical values ​​exemplified here.

[0028] The chloroprene polymer according to one embodiment of the present invention preferably contains 60 to 95 mass% of a chloroprene polymer having a weight-average molecular weight of 500,000 to 1,500,000, based on 100 mass% of the chloroprene polymer. The chloroprene polymer according to one embodiment of the present invention may contain, for example, 60, 65, 70, 75, 80, 85, 90, or 95 mass% of a chloroprene polymer having a weight-average molecular weight of 500,000 to 1,500,000, based on 100 mass% of the chloroprene polymer, and may be within a range between any two of the numerical values ​​exemplified here.

[0029] By adjusting the contents of the chloroprene polymers having different weight-average molecular weights to fall within the above ranges, the storage modulus and loss modulus can be adjusted more appropriately.

[0030] A dip-molded product containing a chloroprene polymer according to one embodiment of the present invention has a storage modulus E′ of 3.2 MPa or less and a loss modulus E″ of 0.37 MPa or less in a frequency range of 10 Hz, as measured by a non-resonant forced vibration method under conditions of a static tension of 5 gf, a temperature of 25°C, a strain of 0.75%, and an amplitude of 0.15 mm.

[0031] Here, the dip-molded product is a dip-molded product obtained by molding a chloroprene polymer latex composition containing the chloroprene polymer by a dip coagulation method, followed by heat drying at 150°C for 60 minutes. That is, the dip-molded product containing a chloroprene polymer can be obtained by dip-molding a chloroprene polymer latex composition containing a chloroprene polymer by a dip coagulation method, and then heat drying the resulting product at 150°C for 60 minutes. The dip-molded product can contain a chloroprene polymer as a base polymer, and when the dip-molded product is taken as 100% by mass, the chloroprene polymer can account for 70% by mass or more, preferably 80% by mass or more, and more preferably 90% by mass or more. When the dip-molded product is taken as 100% by mass, the content of the chloroprene polymer in the dip-molded product is, for example, 70, 75, 80, 85, 90, 95, 96, 97, 98, 99, or 100% by mass, and may be within a range between any two of the values ​​exemplified here.

[0032] The storage modulus E′ of the dip-molded product containing a chloroprene polymer is 3.2 MPa or less, and more preferably 3.0 or less. The storage modulus E′ may be, for example, 3.2, 3.1, 3.0, 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.1, 2.0, 1.9, 1.8, 1.7, 1.6, or 1.5 MPa, and may be within any of the ranges of values ​​exemplified here.

[0033] The loss modulus E" of the dip-molded product containing a chloroprene polymer is preferably 0.37 MPa or less, and more preferably 0.35 or less. The loss modulus E" is, for example, 0.37, 0.35, 0.33, 0.32, 0.31, 0.30, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21, 0.20, 0.19, or 0.18 MPa, and may be within a range between any two of the values ​​exemplified here.

[0034] The storage modulus E′ and loss modulus E″ of a dip-molded product containing a chloroprene polymer can be controlled by adjusting the type (weight average molecular weight, type and content of monomer units contained, etc.) and amount of the chloroprene polymer contained in the dip-molded product. The storage modulus E′ and loss modulus E″ of the dip-molded product can be measured by the method described later in the Examples.

[0035] In one embodiment of the present invention, the tensile strength at break of a dip-molded product containing a chloroprene polymer, measured in accordance with JIS K6251, is, for example, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40 MPa, or may be within a range between any two of the values ​​exemplified here.

[0036] The tensile strength at break of a dip-molded product containing a chloroprene polymer can be controlled by adjusting the type (weight average molecular weight, type and content of monomer units contained, etc.) and amount of the chloroprene polymer contained in the dip-molded product. The tensile strength at break can be measured as described in the Examples.

[0037] 2. Chloroprene polymer latex A chloroprene polymer latex according to one embodiment of the present invention includes the chloroprene polymer according to the present invention. A dip-molded product according to one embodiment of the present invention is obtained using a chloroprene polymer latex composition containing the chloroprene polymer latex. The chloroprene polymer latex may be one in which a chloroprene polymer is dispersed in water, and at least one selected from the group consisting of a chloroprene homopolymer, a copolymer of chloroprene and 1-chloro-1,3-butadiene, a copolymer of chloroprene and 2,3-dichloro-1,3-butadiene, and a copolymer of chloroprene, 1-chloro-1,3-butadiene, and 2,3-dichloro-1,3-butadiene may be dispersed in water. Alternatively, the chloroprene homopolymer or the copolymer of chloroprene and 2,3-dichloro-1,3-butadiene may be dispersed in water.

[0038] 3. Method for producing chloroprene polymer latex Next, a method for producing the chloroprene polymer latex contained in the chloroprene polymer latex composition used to obtain the dip-molded product of the chloroprene polymer of the present invention will be described.

[0039] The method for producing a chloroprene polymer latex may include a polymerization step of polymerizing a chloroprene-containing monomer to obtain a chloroprene polymer latex, and may further include a mixing step of mixing two or more chloroprene polymer latexes having different weight-average molecular weights.

[0040] In the polymerization process, the monomer includes chloroprene and may also include other monomers copolymerizable with chloroprene, such as 1-chloro-1,3-butadiene, 2,3-dichloro-1,3-butadiene, isoprene, styrene, methacrylic acid, acrylonitrile, and sulfur. The monomer may also include chloroprene and 2,3-dichloro-1,3-butadiene.

[0041] The type and amount of each monomer are preferably adjusted so that the content of each monomer unit in the resulting chloroprene polymer falls within the above-mentioned range. For example, the copolymerization amount of 2,3-dichloro-1,3-butadiene in the chloroprene polymer contained in the chloroprene polymer latex can be set to a range of 0 to 30 mass% relative to 100 mass% of the total of the chloroprene monomer and 2,3-dichloro-1,3-butadiene contained in the chloroprene polymer. In this case, the amount of 2,3-dichloro-1,3-butadiene charged before the start of emulsion polymerization is preferably set to a range of 0 to 30 parts by mass relative to 100 parts by mass of the total of the chloroprene monomer and 2,3-dichloro-1,3-butadiene monomer. From the viewpoint of controlling the polymerization, it is more preferable to set the amount of 2,3-dichloro-1,3-butadiene charged to 5 to 25 parts by mass per 100 parts by mass of the total of the chloroprene monomer and the 2,3-dichloro-1,3-butadiene monomer.

[0042] When producing a chloroprene polymer, raw material monomers are polymerized by a polymerization method such as emulsion polymerization, solution polymerization, suspension polymerization, bulk polymerization, etc. Among these polymerization methods, emulsion polymerization is preferred because it has various advantages such as ease of control, ease of extracting the polymer from the polymerization-finished liquid, and a relatively fast polymerization rate.

[0043] Emulsion polymerization is a type of radical polymerization in which raw material monomers are polymerized by being introduced into a reaction vessel together with a chain transfer agent, water, an alkali (e.g., a metal hydroxide such as potassium hydroxide or sodium hydroxide), an emulsifier (dispersant), a reducing agent (e.g., sodium hydrogen sulfite), a polymerization initiator, etc.

[0044] The type of chain transfer agent used in emulsion polymerization is not particularly limited, and known chain transfer agents generally used in emulsion polymerization of chloroprene can be used, such as long-chain alkyl mercaptans such as n-dodecyl mercaptan and tert-dodecyl mercaptan, dialkyl xanthogen disulfides such as diisopropyl xanthogen disulfide and diethyl xanthogen disulfide, iodoform, etc. As the chain transfer agent, long-chain alkyl mercaptans are preferred, and n-dodecyl mercaptan is more preferred.

[0045] By adjusting the type and amount of the chain transfer agent, the weight average molecular weight of the resulting chloroprene polymer latex can be adjusted.

[0046] For example, to obtain a latex containing a chloroprene polymer having a weight-average molecular weight of 500,000 or more, i.e., to obtain a chloroprene polymer latex having a peak indicating a weight-average molecular weight of 500,000 or more in its molecular weight distribution, the amount of chain transfer agent added before the start of emulsion polymerization is preferably 0.01 part by mass or more per 100 parts by mass of monomer (e.g., 100 parts by mass of chloroprene and 2,3-dichloro-1,3-butadiene in total). From the viewpoint of obtaining a chloroprene polymer latex having a peak indicating a weight-average molecular weight of 500,000 or more, the amount of chain transfer agent added is more preferably 0.02 to 0.05 part by mass, and may be, for example, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09 part by mass, or less than 0.10 part by mass, and may be within a range between any two of the values ​​exemplified herein. When the amount of the chain transfer agent, particularly long-chain alkyl mercaptans, added is 0.01 parts by mass or more, the storage stability of the latex is further improved. When the amount is less than 0.10 parts by mass, particularly less than 0.05 parts by mass, the toluene-insoluble matter increases, and the breaking strength of the dip-molded product containing the obtained chloroprene polymer latex is further increased.

[0047] To obtain a latex containing a chloroprene polymer having a weight-average molecular weight of 3,000 to 80,000, i.e., to obtain a chloroprene polymer latex having a peak of a weight-average molecular weight of 3,000 to 80,000 in its molecular weight distribution, the amount of chain transfer agent added before the start of emulsion polymerization is preferably 0.5 to 10.0 parts by mass per 100 parts by mass of monomer. In this case, the amount may be, for example, 0.5, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, or 10.0 parts by mass, or may be within a range between any two of the values ​​exemplified here.

[0048] Examples of emulsifiers include anionic emulsifiers and nonionic emulsifiers. Examples of anionic emulsifiers include fatty acid salts such as potassium tallow fatty acid, partially hydrogenated potassium tallow fatty acid, potassium oleate, and sodium oleate; resin acid salts such as potassium rosinate, sodium rosinate, hydrogenated potassium rosinate, and hydrogenated sodium rosinate; alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate; and sodium salts of β-naphthalene sulfonic acid formalin condensates. Examples of nonionic emulsifiers include polyethylene glycol ester-type emulsifiers and polyvinyl alcohol. Among these, anionic emulsifiers are preferred, resin acid salts are preferred, and rosin acids such as rosin acid and rosin acid salts are preferred, with at least one selected from the group consisting of potassium rosinate and sodium rosinate being more preferred. These emulsifiers can be used alone or in combination. The amount of emulsifier used is preferably 1.0 to 6.5 parts by mass per 100 parts by mass of the monomer.

[0049] In particular, the emulsifier used in emulsion polymerization preferably contains an anionic emulsifier, and more preferably contains a resin acid salt, particularly a rosin acid. The use of a rosin acid can prevent aggregation of rubber solids and pH fluctuations when blended with a base chloroprene polymer latex. Rosin acids include disproportionated rosin acid, conjugated resin acid, alkali metal salts of disproportionated rosin acid, alkali metal salts of conjugated resin acid, etc.

[0050] In the method for producing a chloroprene polymer latex according to one embodiment of the present invention, in addition to the rosin acids, other commonly used emulsifiers or fatty acids can also be used in combination. Examples of the other emulsifiers include, for example, an anionic emulsifier, such as the above-mentioned anionic emulsifiers, as well as metal salts of aromatic sulfinic acid-formalin condensates, sodium dodecylbenzenesulfonate, potassium dodecylbenzenesulfonate, sodium alkyldiphenylethersulfonate, potassium alkyldiphenylethersulfonate, sodium polyoxyethylene alkylethersulfonate, sodium polyoxypropylene alkylethersulfonate, potassium polyoxyethylene alkylethersulfonate, and potassium polyoxypropylene alkyletherethersulfonate.

[0051] The content of the anionic emulsifier excluding rosin acid is preferably 0.2 to 1.0% by mass relative to 100% by mass of the chloroprene polymer contained in the chloroprene polymer latex. Therefore, the amount of the anionic emulsifier excluding rosin acid added before the start of emulsion polymerization is preferably set within the range of 0.2 to 0.9 parts by mass relative to 100 parts by mass of the monomer (for example, the total of chloroprene and 2,3-dichloro-1,3-butadiene).

[0052] The pH of the aqueous emulsion at the start of emulsion polymerization is preferably 10.5 to 13.5. The aqueous emulsion refers to a mixed solution of a chain transfer agent and a monomer (chloroprene, 2,3-dichloro-1,3-butadiene, etc.) immediately before the start of emulsion polymerization, but also includes cases where the composition changes due to the subsequent addition or divided addition of each component. When the pH of the aqueous emulsion at the start of emulsion polymerization is 10.5 or higher, the polymerization reaction can be controlled more stably. When the pH is 13.5 or lower, excessive viscosity increase during polymerization is suppressed, and the polymerization reaction can be controlled more stably.

[0053] The polymerization temperature for emulsion polymerization is preferably within the range of 5 to 55° C. A temperature of 5° C. or higher is preferred because the emulsion does not freeze, and a temperature of 55° C. or lower is preferred because the chloroprene monomer does not evaporate or boil.

[0054] As the polymerization initiator, potassium persulfate, benzoyl peroxide, ammonium persulfate, hydrogen peroxide, etc., which are used in ordinary radical polymerization, can be used.

[0055] The polymerization conversion rate is preferably in the range of 50 to 95%. The polymerization reaction is terminated by adding a polymerization terminator. If the polymerization conversion rate is 50% or more, the toluene insoluble content tends to increase, and the strength of the resulting dip-molded coating tends to increase. This is also advantageous from the viewpoint of production costs. If the polymerization conversion rate is less than 95%, it is possible to avoid a decrease in polymerization reactivity due to a decrease in unreacted monomer, and thus a decrease in productivity.

[0056] Examples of the polymerization terminator include diethylhydroxyamine, thiodiphenylamine, 4-tert-butylcatechol, 2,2'-methylenebis-4-methyl-6-tert-butylphenol, etc. After the emulsion polymerization is completed, unreacted monomers can be removed by a conventional method such as vacuum distillation.

[0057] Furthermore, to the chloroprene polymer latex obtained by the production method according to one embodiment of the present invention, after polymerization, any additive such as a freeze stabilizer, an emulsion stabilizer, a viscosity modifier, an antioxidant, or a preservative may be added, as long as the effects of the present invention are not impaired.

[0058] The method for producing a chloroprene polymer latex according to one embodiment of the present invention may further include a mixing step of mixing two or more chloroprene polymer latexes having different weight-average molecular weights after the polymerization step. In the mixing step, the two or more chloroprene polymer latexes may be mixed by a known method. In the mixing step, the chloroprene polymer latex may be obtained by stirring and mixing using a paddle blade at 30 to 300 rpm for 20 seconds to 3 minutes, e.g., at 100 rpm for 2 minutes.

[0059] 4. Chloroprene polymer latex composition A chloroprene polymer latex composition according to one embodiment of the present invention includes a chloroprene polymer latex containing the chloroprene polymer according to the present invention. The chloroprene polymer latex composition according to one embodiment of the present invention may contain a metal oxide, an antioxidant, and other necessary chemicals in addition to the chloroprene polymer latex. The types and amounts of the metal oxide, antioxidant, and other necessary chemicals that may be contained in the chloroprene polymer latex composition will be described below as components that may be contained in the dip-molded product.

[0060] 5. Method for producing chloroprene polymer latex composition The method for producing the chloroprene polymer latex composition may include a raw material mixing step of mixing raw materials including the chloroprene polymer latex, a metal oxide, an antioxidant, and other necessary chemicals. In the mixing step, an aqueous dispersion containing a metal oxide, an antioxidant, and other necessary chemicals may be prepared in advance, and the chloroprene polymer latex and the aqueous dispersion may be mixed. The mixing step can be carried out using a known mixing device such as a ball mill.

[0061] 6. Dip-molded products (dip-molded coatings and films) A dip-molded article according to one embodiment of the present invention is obtained using a chloroprene polymer latex composition containing the above-described chloroprene polymer latex. The dip-molded article of this embodiment can be obtained by dip-molding the above-described chloroprene polymer latex composition, either alone or in a blend with other chloroprene polymer latex compositions, and then dip-molding the chloroprene polymer latex composition containing a chloroprene polymer by a dip coagulation method, followed by heat drying at 150°C for 60 minutes. The dip-molded article according to the present invention has low storage modulus and loss modulus and excellent mechanical properties such as tensile strength at break. The dip-molded article can be suitably used as industrial and household gloves, medical gloves, balloons, catheters, and boots.

[0062] The dip-molded product according to the present invention may contain components contained in the chloroprene polymer latex. The dip-molded product may contain a chloroprene polymer as a base polymer, and may contain 70% by mass or more, preferably 80% by mass or more, and more preferably 90% by mass or more of the chloroprene polymer, based on 100% by mass of the dip-molded product. The content of the chloroprene polymer in the dip-molded product based on 100% by mass of the dip-molded product may be, for example, 70, 75, 80, 85, 90, 95, 96, 97, 98, 99, or 100% by mass, or may be within a range between any two of the values ​​exemplified here.

[0063] The dip-molded product containing the chloroprene polymer according to the present invention has an excellent texture regardless of whether a vulcanizing agent and a vulcanization accelerator are added, and when made into a glove, it exhibits an excellent wearing comfort. The chloroprene polymer latex composition according to one embodiment of the present invention may be one that does not contain a vulcanizing agent or a vulcanization accelerator, and may not contain sulfur or a vulcanization accelerator such as a thiuram, dithiocarbamate, thiourea, guanidine, xanthogenate, or thiazole. Components that the dip-molded product according to the present invention may contain are described in detail below.

[0064] 6.1 Metal oxides The dip-molded product of the chloroprene polymer according to the present invention may contain a metal oxide. The metal oxide contained in the chloroprene polymer latex composition used to obtain the dip-molded product is not particularly limited, and examples thereof include zinc oxide, lead oxide, trilead tetroxide, magnesium oxide, aluminum oxide, iron oxide, beryllium oxide, and titanium oxide. The metal oxide preferably contains zinc oxide. Zinc oxide is generally believed to function as a scavenger for dechlorinated atoms in chloroprene polymers. These metal oxides may be used alone or in combination of two or more.

[0065] The amount of metal oxide added is preferably 0.5 to 15.0 parts by mass per 100 parts by mass of the solid content of the chloroprene polymer latex contained in the chloroprene polymer latex composition used to obtain the dip-molded product. When the amount of metal oxide added is 0.5 parts by mass or more, improved breaking strength is expected due to the crosslinking effect between polymers. When the amount of metal oxide added is 15.0 parts by mass or less, a dip-molded product with excellent flexibility can be obtained. Furthermore, from the viewpoint of the balance between the flexibility and breaking strength of the obtained dip-molded product, the amount of metal oxide added is more preferably 0.5 to 5.0 parts by mass.

[0066] 6.2 Antioxidants The dip-molded product of the chloroprene polymer according to the present invention may also contain an antioxidant. The antioxidant is not particularly limited, and examples thereof include phenolic antioxidants, amine-based antioxidants, heat-resistant oxidation (aging) inhibitors, and ozone-resistant antioxidants. When the resulting dip-molded product is used as a medical glove, phenolic antioxidants can be used from the viewpoints of color, texture, and hygiene of the dip-molded product. Hindered phenolic antioxidants are particularly effective. Examples of hindered phenolic antioxidants include 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 2,2'-methylenebis(4-methyl-6-t-butylphenol), 4,4'-butylidene(3-methyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), butylated reaction products of p-cresol and dicyclopentadiene, 2,5'-di-t-butylhydroquinone, and 2,5'-di-t-amylhydroquinone. Among these, the butylated reaction product of p-cresol and dicyclopentadiene is desirable from the viewpoint of general dispersibility in aqueous materials. These compounds may be used alone or in combination of two or more.

[0067] The amount of antioxidant added is preferably 0.5 to 10.0 parts by mass per 100 parts by mass of the solids content of the chloroprene polymer latex contained in the chloroprene polymer latex composition used to obtain the dip-molded product. The amount of antioxidant added is, for example, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, or 10.0 parts by mass, and may be within a range between any two of the values ​​exemplified here. When the amount of antioxidant added is 0.5 parts by mass or more, the effect of suppressing color change in the dip-molded product can be obtained. When the amount of antioxidant added is 10.0 parts by mass or less, the stability of the chloroprene polymer latex composition can be ensured. Furthermore, from the viewpoint of the balance of physical properties between flexibility and breaking strength of the obtained dip-molded product, the amount of antioxidant added is more preferably 0.5 to 5.0 parts by mass.

[0068] 6.3 Vulcanizing agents and vulcanization accelerators The dip-molded product of a chloroprene polymer according to one embodiment of the present invention may contain a vulcanizing agent and / or a vulcanization accelerator. The chloroprene polymer latex composition used to obtain the dip-molded product may not contain sulfur or the aforementioned thiuram-based, dithiocarbamate-based, thiourea-based, guanidine-based, xanthogenate-based, thiazole-based, or other vulcanization accelerators. That is, the chloroprene polymer latex composition encompasses those containing a vulcanizing agent but not a vulcanization accelerator, those containing a vulcanizing agent but not a vulcanization accelerator, those containing a vulcanizing agent and a vulcanization accelerator, and those containing neither a vulcanizing agent nor a vulcanization accelerator. Whether or not a vulcanizing agent and a vulcanization accelerator are added may be determined depending on the desired dip-molded product.

[0069] Examples of vulcanizing agents include, but are not limited to, sulfur. The amount of vulcanizing agent added can be 0 to 10.0 parts by mass per 100 parts by mass of the solid content of the chloroprene polymer latex contained in the chloroprene polymer latex composition. The amount of vulcanizing agent added is, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts by mass, and may be within a range between any two of the values ​​exemplified here.

[0070] A vulcanization accelerator is a chemical added during the vulcanization of raw rubber to act with the vulcanizing agent to increase the vulcanization speed, thereby shortening the vulcanization time, lowering the vulcanization temperature, reducing the amount of vulcanizing agent, and improving the physical properties of the vulcanized rubber. It usually refers to a chemical that accelerates the sulfur vulcanization reaction.

[0071] Vulcanization accelerators generally used in the vulcanization of chloroprene polymer latex include, but are not limited to, thiuram-based, dithiocarbamate-based, thiourea-based, guanidine-based, xanthogenate-based, thiazole-based, etc. These may be used alone or in combination of two or more types as required.

[0072] Examples of thiuram vulcanization accelerators include tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetrakis(2-ethylhexyl)thiuram disulfide, tetramethylthiuram monosulfide, and dipentamethylenethiuram tetrasulfide.

[0073] Examples of dithiocarbamate vulcanization accelerators include sodium dibutyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc N-ethyl-N-phenyldithiocarbamate, zinc N-pentamethylenedithiocarbamate, copper dimethyldithiocarbamate, ferric dimethyldithiocarbamate, and tellurium diethyldithiocarbamate, with zinc dibutyldithiocarbamate being particularly preferred.

[0074] Examples of the thiourea-based vulcanization accelerator include ethylene thiourea, N,N'-diethyl thiourea, trimethyl thiourea, and N,N'-diphenyl thiourea.

[0075] Examples of the guanidine vulcanization accelerator include 1,3-diphenylguanidine, 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, and di-o-tolylguanidine salts of dicatechol borate.

[0076] Examples of xanthogenate-based vulcanization accelerators include zinc butylxanthogenate and zinc isopropylxanthogenate.

[0077] Examples of the thiazole vulcanization accelerator include 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, 2-mercaptobenzothiazole zinc salt, cyclohexylamine salt of 2-mercaptobenzothiazole, and 2-(4'-morpholinodithio)benzothiazole.

[0078] The amount of the vulcanization accelerator added can be 0 to 5.0 parts by mass relative to 100 parts by mass of the solid content of the chloroprene polymer latex contained in the chloroprene polymer latex composition, and may be, for example, 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, or 5.0, or may be within a range between any two of the numerical values ​​exemplified here.

[0079] 6.4 Other drugs (heteroaromatic ring compounds) The dip-molded product of the chloroprene polymer according to the present invention may contain a heteroaromatic ring compound in the chloroprene polymer. The heteroaromatic ring compound contained in the chloroprene polymer latex composition used to obtain the dip-molded product can be represented by chemical formula (1) and has a benzimidazole structure. Compounds having this structure are sometimes used as secondary antioxidants, mainly in the formulation of rubber compositions.

[0080] [ka]

[0081] In chemical formula (1), X of the mercapto group represents a hydrogen atom or a metal atom. X may be a hydrogen atom, resulting in a thiol group. X may also be a metal atom, such as zinc, sodium, copper, nickel, or tellurium, with zinc being preferred. In chemical formula (1), R1 to R4 represent a hydrogen atom, an alkyl group which may have a substituent, an ether group which may have a substituent, a nitro group, an amino group, or a carboxyl group, respectively. R1 to R4 may be the same or different. The heteroaromatic ring compounds may be used singly or in combination of two or more.

[0082] Examples of heteroaromatic ring compounds include 2-mercaptobenzimidazole, 5-methyl-2-mercaptobenzimidazole, 4-methyl-2-mercaptobenzimidazole, 5-methoxy-2-mercaptobenzimidazole, 4-methoxy-2-mercaptobenzimidazole, 5-nitro-2-mercaptobenzimidazole, 5-amino-2-mercaptobenzimidazole, 5-carboxy-2-mercaptobenzimidazole, and zinc salts of 2-mercaptobenzimidazole. Among these, 2-mercaptobenzimidazole, 5-methyl-2-mercaptobenzimidazole, 4-methyl-2-mercaptobenzimidazole, 5-methoxy-2-mercaptobenzimidazole, 4-methoxy-2-mercaptobenzimidazole, and zinc salts of 2-mercaptobenzimidazole are preferred.

[0083] The amount of the heteroaromatic ring compound added is preferably 0.2 to 10.0 parts by mass per 100 parts by mass of the solids content of the chloroprene polymer latex contained in the chloroprene polymer latex composition. The amount of the heteroaromatic ring compound added is, for example, 0.2, 0.3, 0.4, 0.5, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, or 10.0 parts by mass, and may be within a range between any two of the values ​​exemplified here. When the amount added is 0.2 parts by mass or more, the dip-molded article obtained using this composition exhibits very high breaking strength. When the amount added is 10.0 parts by mass or less, the stability of the chloroprene polymer latex composition is ensured. Furthermore, from the viewpoint of the balance between the flexibility and breaking strength of the resulting dip-molded article, the amount added is more preferably 0.3 to 5.0 parts by mass.

[0084] 6.5 Properties of Dip-molded Products A dip-molded product according to one embodiment of the present invention is cut into a strip-shaped test piece (width: 4.5 mm, length: 30 mm) and subjected to tensile dynamic viscoelasticity measurement (chuck distance: 20 mm) according to a non-resonant forced vibration method under a static tension of 5 gf, a temperature of 25°C, and a strain of 0.75% (amplitude: 0.15 mm). When the dip-molded product is subjected to tensile dynamic viscoelasticity measurement (chuck distance: 20 mm) according to a non-resonant forced vibration method, the storage modulus E' in the 10 Hz frequency range is 3.2 MPa or less, and preferably 3.0 MPa or less. The storage modulus may be, for example, 3.2, 3.1, 3.0, 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.1, 2.0, 1.9, 1.8, 1.7, 1.6, or 1.5 MPa, or may be within any of the ranges of values ​​exemplified here.

[0085] The dip-molded product according to the present invention is formed into a strip-shaped test piece (width: 4.5 mm, length: 30 mm) and subjected to tensile dynamic viscoelasticity measurement (chuck distance: 20 mm) in accordance with a non-resonant forced vibration method under a static tension of 5 gf, a temperature of 25°C, and a strain of 0.75% (amplitude: 0.15 mm). When this measurement is performed, the loss modulus E" in the 10 Hz frequency range is 0.37 MPa or less, and more preferably 0.35 MPa or less. The loss modulus E" is, for example, 0.37, 0.35, 0.33, 0.32, 0.31, 0.30, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21, 0.20, 0.19, or 0.18 MPa, and may be within a range between any two of the values ​​exemplified here.

[0086] Both the storage modulus E' and the loss modulus E" affect the feel and wearing comfort of the dip-molded product when it is used as a glove, which is the main application of the dip-molded product. By controlling the storage modulus E' to be not more than the above upper limit and the loss modulus E" to be not more than the above upper limit, a dip-molded product having an excellent feel and excellent wearing comfort when molded into a glove can be obtained.

[0087] The breaking strength of the dip-molded product according to the present invention, as measured in accordance with JIS K6251, is desirably 17 MPa or more. In particular, the ASTM standard "D3577" for surgical glove applications specifies a breaking strength of 17 MPa or more, and a breaking strength of 20 MPa is considered to exhibit even more sufficient mechanical properties. As described above, the dip-molded product of the chloroprene polymer according to one embodiment of the present invention can be made to have sufficient tensile strength at break, while also exhibiting excellent texture as a dip-molded product (film) and excellent wearing comfort when made into gloves.

[0088] The dip-molded product contains a chloroprene polymer and may further contain an antioxidant and a metal oxide. The dip-molded product may also contain a vulcanizing agent, a vulcanization accelerator, and other chemicals. The method for producing the dip-molded product and the methods for measuring the storage modulus E', loss modulus E", and breaking strength may be as described in the Examples. As described above, the storage modulus E', loss modulus E" and breaking strength of the dip-molded product containing the chloroprene polymer latex composition can be controlled by adjusting the weight-average molecular weight and the degree of crosslinking through the adjustment of the type and amount of the chloroprene polymer latex composition, the polymerization recipe and conditions of the chloroprene polymer latex used, the heat drying conditions in preparing the dip-molded product, etc.

[0089] 6.6 Weight average molecular weight of dip-molded product The dip-molded product according to one embodiment of the present invention may have a peak at a weight-average molecular weight of 3,000 to 80,000 in the molecular weight distribution obtained by measuring the tetrahydrofuran-soluble sol content in the dip-molded product by gel permeation chromatography, and the peak is preferably at a weight-average molecular weight of 5,000 to 50,000.

[0090] In the molecular weight distribution, when the weight-average molecular weight at the peak is equal to or greater than the lower limit, better breaking strength can be obtained. The weight-average molecular weight at the peak may be 10,000 or more, or 15,000 or more, from the viewpoint of more easily obtaining a dip-molded article.

[0091] In the molecular weight distribution, when the peak weight-average molecular weight is equal to or less than the upper limit, even better flexibility can be obtained. From the viewpoint of easily obtaining even better flexibility, the peak weight-average molecular weight of the dip-molded product of the chloroprene polymer may be 80,000 or less, 70,000 or less, 50,000 or less, or 30,000 or less.

[0092] The weight average molecular weight of the peak may be, for example, 3,000, 4,000, 5,000, 6,000, 7,000, 8,000, 9,000, 10,000, 11,000, 12,000, 13,000, 14,000, 15,000, 16,000, 17,000, 18,000, 19,000, 20,000, 21,000, 22,000, 23,000, 24,000, 25,000, 26,000, 27,000, 28,000, 29,000, 30,000, 31,000, 32,000, 33,000, 34,000, 35,000, 36,000, 37,000, 38,000, 39,000, 40,000, 41,000, 42,000, 43,000, 44,000, 45,000, 46,000, 47,000, 48,000, 49,000, 50,000, 51,000, 52,000, 53,000, 54,000, 55,000, 56,000, 57,000, 58,000, 59,000, 60,000, 61,000, 62,000, 63,000, 64,000, 65,000, 00, 22,000, 23,000, 24,000, 25,000, 26,000, 27,000, 28,000, 29,000, 30,000, 35,000, 40,000, 50,000, 60,000, 70,000, 80,000, and may be within a range between any two of the numerical values ​​exemplified here.

[0093] The dip-molded product of a chloroprene polymer according to one embodiment of the present invention preferably has a peak in the above range in the molecular weight distribution.

[0094] The dip-molded product of the chloroprene polymer according to one embodiment of the present invention has the above-mentioned molecular weight distribution, and therefore has low values ​​of storage modulus E′ and loss modulus E″ in dynamic viscoelasticity measurement, and can have excellent texture and wearing comfort.

[0095] The dip-molded product according to one embodiment of the present invention may further have a peak at a weight-average molecular weight of 500,000 to 1,500,000 in the molecular weight distribution obtained by measuring the tetrahydrofuran-soluble sol component of the dip-molded product by gel permeation chromatography. The peak position detected in the weight-average molecular weight range of 500,000 to 1,500,000 may be, for example, 500,000, 600,000, 700,000, 800,000, 900,000, 1,000,000, 1,200,000, 1,300,000, 1,400,000, or 1,500,000, or may be within a range between any two of the numerical values ​​exemplified here.

[0096] In the dip-molded product according to one embodiment of the present invention, a peak corresponding to a weight-average molecular weight of 3,000 to 80,000 and a peak corresponding to a weight-average molecular weight of 500,000 to 1,500,000 are preferably detected in the molecular weight distribution obtained by measuring the tetrahydrofuran-soluble sol content of the dip-molded product by gel permeation chromatography.

[0097] The dip-molded product according to one embodiment of the present invention preferably contains 5 to 40 mass% of a chloroprene polymer having a weight-average molecular weight of 3,000 to 80,000, based on 100 mass% of the chloroprene polymer contained in the dip-molded product. The dip-molded product according to one embodiment of the present invention may contain, based on 100 mass% of the chloroprene polymer, for example, 5, 10, 15, 20, 25, 30, 35, or 40 mass% of a chloroprene polymer having a weight-average molecular weight of 5,000 to 50,000, and may be within a range between any two of the numerical values ​​exemplified here.

[0098] The dip-molded product according to one embodiment of the present invention preferably contains 60 to 95 mass% of a chloroprene polymer having a weight-average molecular weight of 500,000 to 1,500,000, when the total mass of the chloroprene polymer contained in the dip-molded product is taken as 100 mass%. The dip-molded product according to one embodiment of the present invention may contain, for example, 60, 65, 70, 75, 80, 85, 90, or 95 mass% of a chloroprene polymer having a weight-average molecular weight of 500,000 to 1,500,000, when the total mass of the chloroprene polymer contained in the dip-molded product is taken as 100 mass%, and may be within a range between any two of the numerical values ​​exemplified here.

[0099] The molecular weight distribution of the tetrahydrofuran-soluble sol fraction of the dip-molded product according to the present invention can be obtained by, for example, cutting the dip-molded product to a specific size, immersing it in tetrahydrofuran at 25° C. for 24 hours to prepare a 0.1% tetrahydrofuran solution, and measuring the weight-average molecular weight of the solution by gel permeation chromatography. The GPC measurement conditions can be as described in the Examples. In addition, by using a chloroprene polymer latex or a chloroprene polymer latex composition as an analysis target, dissolving the chloroprene polymer latex or the chloroprene polymer latex composition in tetrahydrofuran, and performing analysis in the same manner, it is also possible to determine the molecular weight distribution of the tetrahydrofuran-soluble sol component in the chloroprene polymer latex contained in the chloroprene polymer latex or the chloroprene polymer latex composition.

[0100] The chloroprene polymer latex composition used in producing the dip-molded article of the present invention can be obtained by mixing two or more types of chloroprene polymer latexes having different weight-average molecular weights, as described above. By using two or more types of chloroprene polymer latexes having different weight-average molecular weights, a chloroprene polymer latex in which the above-mentioned peak is detected in the molecular weight distribution may be obtained. When two or more types of chloroprene polymer latexes are mixed, the weight-average molecular weight of each chloroprene polymer latex can be controlled by adjusting the type and amount of chain transfer agent, polymerization temperature, polymerization time, polymerization conversion rate, etc., during polymerization of each chloroprene polymer latex.

[0101] 6.5 Shape of dip-molded product The thickness of the dip-molded product (e.g., the minimum thickness) may be 0.01 to 0.50 mm. The thickness of the dip-molded product may be, for example, 0.01, 0.05, 0.10, 0.20, 0.30, 0.40, or 0.50 mm, or may be within a range between any two of the values ​​exemplified here. The thickness of the dip-molded product can be adjusted by the time the mold is immersed in the polymer latex composition, the solids concentration of the chloroprene polymer latex composition, etc. To reduce the thickness of the dip-molded product, the immersion time may be shortened or the solids concentration of the chloroprene polymer latex composition may be reduced.

[0102] As described above, the dip-molded product according to one embodiment of the present invention has an excellent feel and wearing comfort, and can have sufficient tensile strength at break regardless of whether a vulcanizing agent, vulcanization accelerator, or crosslinking agent is added. Conventional latex containing chloroprene rubber has been used as a rubber latex raw material for dip-molded coatings for gloves, balloons, boots, catheters, etc. On the other hand, particularly in medical rubber glove applications, there is a tendency for high flexibility to be required similar to that of dip-molded products obtained using natural rubber or polyisoprene, and a dip-molded product of a chloroprene polymer having improved texture of the dip-molded product (film) and improved wearing comfort (fit) when made into a glove is desired. The dip-molded product of the present invention has excellent texture and excellent wearing comfort when made into a glove while having mechanical properties equivalent to those of conventional dip-molded products containing chloroprene polymers.

[0103] The dip-molded product obtained from the chloroprene polymer latex composition may contain sulfur or a vulcanization accelerator. However, even if the dip-molded product does not contain sulfur or a vulcanization accelerator, the dip-molded product has mechanical properties equivalent to or superior to those of vulcanized dip-molded products obtained from conventional chloroprene polymer latexes. Therefore, the chloroprene polymer latex composition is suitably used as a raw material for the dip-molded product (dip-molded article) of the chloroprene polymer of this embodiment.

[0104] 7. Manufacturing method of dip-molded products The method for producing a dip-molded product containing a chloroprene polymer according to the present invention comprises the steps of: a molding step of molding the chloroprene polymer latex composition containing the chloroprene polymer by a dip coagulation method using a calcium-based coagulation liquid to obtain a dip-molded product; and A drying step in which the obtained dip-molded body is subjected to a heat drying treatment to obtain a dip-molded product. may include:

[0105] The molding method for producing the immersion molded article of one embodiment of the present invention is not particularly limited, and may be performed according to a conventional method. Examples of molding methods include immersion coagulation, simple immersion, thermal immersion, and electrodeposition. The immersion coagulation method can be used from the viewpoints of ease of production and the ease of obtaining immersion molded articles of a uniform thickness. Specifically, a ceramic mold coated with a calcium-based coagulation liquid is immersed in a chloroprene polymer latex composition to coagulate the chloroprene polymer latex composition. After removing water-soluble impurities by leaching, the composition is dried, and then heated and vulcanized to form a immersion molded film (rubber film), which is then released from the mold. This allows for the production of a film-like immersion molded article.

[0106] Furthermore, a method for producing a dip-molded product according to one embodiment of the present invention may include a step of subjecting the obtained dip-molded product to a heat drying treatment to vulcanize the unvulcanized dip-molded product. The heat drying temperature may be appropriately set depending on the composition of the chloroprene polymer latex composition, and may be 100 to 220°C or 120 to 180°C. The heat drying temperature may be, for example, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, or 220°C, or may be within a range between any two of the values ​​exemplified here. The heat drying time may be appropriately set depending on the composition of the chloroprene polymer latex composition, the shape of the unvulcanized molded product, and the like, and may be 10 to 300 minutes. The heat drying time may be, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, or 300 minutes, or may be within a range between any two of the values ​​exemplified here. As an example, a dip-molded product according to one embodiment of the present invention may be subjected to heat drying treatment at 150°C for 60 minutes. [Example]

[0107] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following examples relating to the synthesis of a chloroprene polymer latex, unless otherwise specified, "parts by mass" refers to the amount relative to 100 parts by mass of the total of the chloroprene monomer and 2,3-dichloro-1,3-butadiene monomer before the start of emulsion polymerization. Furthermore, "% by mass" refers to the amount relative to 100% by mass of the chloroprene polymer contained in the chloroprene polymer latex.

[0108] [Synthesis Example A1] <Preparation of chloroprene polymer latex> A 40-liter polymerization vessel was charged with 91 parts by mass of chloroprene monomer, 9 parts by mass of 2,3-dichloro-1,3-butadiene monomer, 0.02 parts by mass of n-dodecyl mercaptan, 76.5 parts by mass of purified water, 18 parts by mass of gum rosin-based disproportionated potassium rosinate (aqueous solution, solids content 25%) (manufactured by Arakawa Chemical Industries, Ltd., product name: Longis K-25), 0.80 parts by mass of potassium hydroxide, and 0.50 parts by mass of sodium salt of β-naphthalenesulfonic acid formalin condensate (product name: Demol N, manufactured by Kao Corporation). The pH of the aqueous emulsion before polymerization was 13.2. 0.1 parts by mass of potassium persulfate was added as a polymerization initiator, and polymerization was carried out at a polymerization temperature of 15°C under a nitrogen gas flow. When the polymerization conversion reached 83%, 0.01 parts by mass of diethylhydroxyamine as a polymerization terminator was added to terminate the polymerization, yielding a latex.

[0109] The latex was distilled under reduced pressure to remove unreacted monomers and a portion of water, thereby obtaining a chloroprene polymer latex with a solid content of 60%.

[0110] [Synthesis examples A2~A4] Chloroprene polymer latex samples of Synthesis Examples A2 to A4 were prepared in the same manner as in Synthesis Example A1, except that the amounts of 2,3-dichloro-1,3-butadiene and n-dodecyl mercaptan as a chain transfer agent, the polymerization temperature, and the polymerization conversion rate were set as shown in Table 1 below.

[0111] [Synthesis Example B1] <Preparation of chloroprene polymer latex> A 40-liter polymerization vessel was charged with 91 parts by mass of chloroprene monomer, 9 parts by mass of 2,3-dichloro-1,3-butadiene monomer, 3.0 parts by mass of n-dodecyl mercaptan, 76.5 parts by mass of purified water, 18 parts by mass of gum rosin-based disproportionated potassium rosinate (aqueous solution) (manufactured by Arakawa Chemical Industries, Ltd., product name: Longis K-25), 0.80 parts by mass of potassium hydroxide, and 0.50 parts by mass of sodium salt of β-naphthalenesulfonic acid formalin condensate (product name: Demol N, manufactured by Kao Corporation). The pH of the aqueous emulsion before polymerization was 13.1. 0.1 parts by mass of potassium persulfate was added as a polymerization initiator, and polymerization was carried out at a polymerization temperature of 30°C under a nitrogen gas flow. When the polymerization conversion rate reached 83%, 0.01 parts by mass of diethylhydroxyamine as a polymerization terminator was added to terminate the polymerization, yielding a latex.

[0112] The latex was distilled under reduced pressure to remove unreacted monomers, thereby obtaining a chloroprene polymer latex with a solid content of 60%.

[0113] [Synthesis examples B2 to B8] Chloroprene polymer latex samples of Synthesis Examples B2 to B8 were prepared in the same manner as in Synthesis Example B1, except that the amounts of 2,3-dichloro-1,3-butadiene and n-dodecyl mercaptan as a chain transfer agent, the polymerization temperature, and the polymerization conversion rate were set as shown in Table 1 below.

[0114] The resulting chloroprene polymer latex containing the chloroprene polymer was subjected to the following analyses. <Measurement of weight average molecular weight of each chloroprene polymer latex> The polymer precipitated from the obtained chloroprene-based polymer latex using methanol was dissolved in tetrahydrofuran to prepare a 0.1% THF (tetrahydrofuran) solution, and the weight-average molecular weight of the eluted fraction (sol fraction) was measured by gel permeation chromatography (GPC). The detected peak can be obtained as the weight-average molecular weight in terms of polystyrene, and was measured under the conditions described below.

[0115] <Weight-average molecular weight measurement by gel permeation chromatography> GPC measurement was carried out under the following conditions. The weight average molecular weight was calculated in terms of polystyrene. Gel permeation chromatography (GPC) measurement equipment: Tosoh gel permeation chromatograph (HLC-8320) Column: Tosoh TSKgel ALPHA-M Eluent: Tetrahydrofuran (Kanto Chemical) ·Eluent flow rate: 1.0ml / min Column temperature: 40℃ Detection method: Differential refractive index (RI) meter Calibration curve: Created using standard polystyrene

[0116] <Measurement of the amount of copolymerization of 2,3-dichloro-1,3-butadiene> The resulting chloroprene polymer latex was freeze-dried to obtain a chloroprene polymer rubber sample, which was cut into 0.05 mg test pieces and analyzed by pyrolysis gas chromatography to determine the area ratio of the peak derived from chloroprene to the peak derived from 2,3-dichloro-1,3-butadiene. The content of 2,3-dichloro-1,3-butadiene (mass%) in the chloroprene polymer was determined using a calibration curve of the area ratio of the peak derived from chloroprene to the peak derived from 2,3-dichloro-1,3-butadiene and the 2,3-dichloro-1,3-butadiene content.

[0117] <Measurement by pyrolysis gas chromatography> The measurement conditions for the pyrolysis gas chromatograph are shown below. Device name: HP5890-II Column: DB-5 0.25 mm diameter x 30 m (film thickness 1.0 μm) Column temperature: 50°C (5 min) → 10°C / min → 150°C → 25°C / min → 300°C Inlet temperature: 250℃ Detector temperature: 280℃ Detector: FID

[0118] [Table 1]

[0119] [Example 1] When the total amount of the chloroprene polymer latex of Synthesis Example A1 and the chloroprene polymer latex of Synthesis Example B1 was 100 parts by mass, 80 parts by mass of the sample of Synthesis Example A1 and 20 parts by mass of the sample of Synthesis Example B1 were mixed and stirred using a paddle blade at 100 rpm for 2 minutes to obtain the chloroprene polymer latex of Example 1.

[0120] <Measurement of weight average molecular weight of chloroprene polymer latex> The polymer precipitated from the resulting chloroprene polymer-containing latex using methanol was dissolved in tetrahydrofuran and used as a 0.1% THF (tetrahydrofuran) solution. The tetrahydrofuran-soluble fraction was subjected to gel permeation chromatography (GPC) measurement, and a peak corresponding to a weight average molecular weight (Mw) of 22,715 was confirmed. The GPC measurement conditions were the same as those for the weight average molecular weight measurement in each of the above synthesis examples.

[0121] <Amount of 2,3-dichloro-1,3-butadiene copolymerized in chloroprene polymer contained in chloroprene polymer latex> The mixed chloroprene polymer latex was freeze-dried, and the copolymerization amount of 2,3-dichloro-1,3-butadiene in the chloroprene polymer rubber was measured, resulting in a result of 9.5 mass%. This analytical value confirmed that the copolymerization amount of 2,3-dichloro-1,3-butadiene in the chloroprene polymer roughly correlates with the blending amount (charge amount) of 2,3-dichloro-1,3-butadiene. The measurement conditions were the same as those for the pyrolysis gas chromatography measurement in each of the above synthesis examples.

[0122] <Preparation of Dip-molded Body (Dip-molded Body Film Sample)> (Preparation of Chloroprene Polymer Latex Composition) A chloroprene polymer latex composition was prepared by mixing 100 parts by weight of a chloroprene polymer latex solids solution with an aqueous dispersion, and then adding water to adjust the total solids concentration of the blend to 30% by weight. The aqueous dispersion was prepared by mixing 2 parts by weight of two types of zinc oxide, 2 parts by weight of a butylated reaction product of p-cresol and dicyclopentadiene (trade name "Nocrac PBK" manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), 2 parts by weight of zinc dibutyldithiocarbamate (trade name "Noccela BZ" manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), 1 part by weight of sulfur, 0.1 part by weight of a sodium salt of β-naphthalenesulfonic acid formalin condensate (trade name "Demol N" manufactured by Kao Corporation), and 10.7 parts by weight of water in a ceramic ball mill at 20°C for 16 hours. The obtained chloroprene polymer latex composition contains, relative to 100 parts by mass of the solids content of the chloroprene polymer latex, 2 parts by mass of two types of zinc oxide, 2 parts by mass of a butylated reaction product of p-cresol and dicyclopentadiene (trade name "Nocrac PBK", manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), 2 parts by mass of dibutyldithiocarbamic acid (trade name "Noccela BZ", manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), 1 part by mass of sulfur, 0.1 part by mass of a sodium salt of a β-naphthalenesulfonic acid formalin condensate (trade name "Demol N", manufactured by Kao Corporation), and water.

[0123] (Preparation of Dip-molded Film of Chloroprene Polymer) A ceramic surgical glove mold (manufactured by Shinko Co., Ltd.) with a palm circumference of 7.5 inches was immersed for 1 second in a coagulation solution containing 62 parts by mass of water, 35 parts by mass of calcium nitrate tetrahydrate, and 3 parts by mass of calcium carbonate, and then removed. After drying for 3 minutes, the molded glove was immersed for 2 minutes in the chloroprene polymer latex composition prepared by the procedure described above. The molded glove was then washed with running water at 45°C for 1 minute and dried at 150°C for 60 minutes to prepare a dipped molded product (glove-shaped film) for evaluation.

[0124] <Evaluation of dip-molded products> (film thickness) The thickness (film thickness) of the evaluation film was measured at three points in the center using a test piece thickness measuring instrument (manufactured by Kobunshi Keiki Co., Ltd., product name: ASKER SDA-12), and the smallest thickness was taken as the thickness of the evaluation film.

[0125] (Storage modulus E' and loss modulus E") Dip-molded film samples were cut out to prepare rectangular test specimens (width: 4.5 mm, length: 30 mm). Using the obtained rectangular test specimens, tensile dynamic viscoelasticity measurements (chuck distance: 20 mm) were performed in accordance with the non-resonant forced vibration method. The measurement conditions were static tension of 5 gf, temperature of 25°C, strain of 0.75% (amplitude: 0.15 mm), and the storage modulus E' and loss modulus E" were measured in the 10 Hz frequency range. The measurement device used was a DDV-25FP manufactured by Orientec Co., Ltd. The results are shown in Tables 2 and 3. The thickness of the test specimens can be adjusted to 0.18 to 0.21 mm, as shown in Tables 2 and 3.

[0126] (tensile strength at break) The tensile strength at break of the dip-molded film was measured in accordance with JIS K 6251. The results are shown in Tables 2 and 3.

[0127] <Measurement of weight average molecular weight of dip-molded product> The dip-molded product containing the chloroprene polymer was cut into 2 mm squares, and the cut dip-molded product was placed in 20 ml of tetrahydrofuran to form a 0.1% solution, and dissolved for 24 hours. The resulting tetrahydrofuran-soluble fraction was then subjected to gel permeation chromatography (GPC). A peak corresponding to a weight-average molecular weight (Mw) of 22,715 was observed. The GPC measurement conditions were the same as those for the weight-average molecular weight measurement in each of the above synthesis examples. The results are shown in Tables 2 and 3.

[0128] <Evaluation of texture of glove-shaped dipped molded products> Five subjects were asked to touch the resulting dipped molded products (glove-like films) and evaluate the texture of the dipped molded products by touching the surface, stretching, and bending them. The evaluation was based on the following criteria, and the average of each subject's evaluation was rounded off to the nearest whole number.

[0129] (Texture evaluation criteria) 3: Extremely soft and pleasant to the touch, with an excellent texture 2: It was soft, had no practical problems with the feel, and had a good texture. 1: It didn't feel very soft, it felt a little hard to the touch, and the texture was not good.

[0130] <Evaluation of wearing comfort of glove-shaped dipped molded products> Five subjects were asked to wear the resulting glove-shaped dipped products, and evaluations of wearability were conducted by focusing on the adhesion (fit) to the hand and the degree of deformation after removal. Evaluations were conducted according to the following criteria, and the average of each subject's evaluation was rounded up or down to the nearest whole number.

[0131] (Wearability evaluation criteria) 3: It has an excellent fit when worn, is easy to work with, and returns to its original shape immediately (within 5 minutes) after being put on and taken off, so it is comfortable to wear. 2: The mask fits to a certain extent, and although it takes time (more than 5 minutes) to return to its original shape after putting it on and taking it off, there are no practical problems and the wearing comfort is good. 1: The fit was poor and the immersion molding was deformed after putting on and taking off, so the fit was not good.

[0132] [Examples 2 to 11, Comparative Examples 1 to 6] Dip-molded products were prepared in the same manner as in Example 1, except that the formulation of the chloroprene polymer latex composition was set as shown in Tables 2 and 3 below. Each dip-molded film sample was then produced and evaluated. In Examples 2 to 3, 9, and 10 and Comparative Examples 1 to 3 and 6, the dip-molded product did not contain a low-molecular-weight chloroprene polymer having a weight-average molecular weight of 3,000 to 80,000, or the type of low-molecular-weight chloroprene polymer having a weight-average molecular weight of 3,000 to 80,000 contained in the dip-molded product was changed, or the dip-molded product contained only a low-molecular-weight chloroprene polymer. In Examples 4 and 5 and Comparative Examples 4 and 5, the type and mixing ratio of each chloroprene polymer latex contained in the dip-molded product were changed. In Example 6, a dip-molded product was obtained without using dibutyldithiocarbamic acid as a vulcanization accelerator and sulfur as a vulcanizing agent contained in the chloroprene polymer latex composition of Examples 1 to 5. In Example 7, no vulcanization accelerator or sulfur was used, and instead, 1 part by mass of a heteroaromatic ring compound represented by the following chemical formula (2) (2-mercaptobenzimidazole, trade name "Nocrac MB", manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) was added as an additional agent relative to 100 parts by mass of the chloroprene polymer. In Example 8 and Comparative Example 2, no vulcanization accelerator or sulfur was used, and a chloroprene polymer not copolymerized with 2,3-dichloro-1,3-butadiene was used as the chloroprene polymer contained in the composition. In Example 11, the amount of zinc oxide, which has a crosslinking effect, added was changed.

[0133] [ka]

[0134] [Table 2]

[0135] [Table 3]

[0136] As is clear from Tables 2 and 3 above, the dip-molded products (dip-molded films) of the chloroprene polymers of the present invention in Examples 1 to 11 had low values ​​of storage modulus E′ and loss modulus E″ in the tensile dynamic viscoelasticity measurement, and had sufficient tensile strength at break. The dip-molded products (dip-molded films) also had excellent texture and were comfortable to wear when made into gloves.

[0137] The dip-molded product of Comparative Example 1 did not have a low molecular weight peak and was likely to have a high storage modulus due to the strong influence of the degree of crosslinking. As a result, the feel of the dip-molded film was poor.

[0138] The dip-molded product of Comparative Example 2 did not have a low-molecular-weight peak, and 2,3-dichloro-1,3-butadiene was not copolymerized. The crosslinking degree and crystallinity of the chloroprene polymer had a strong effect on the storage modulus even without the addition of a vulcanization accelerator or sulfur. As a result, the feel of the dip-molded film was poor.

[0139] The dip-molded product of Comparative Example 3 had a high ratio of chloroprene polymer with a low molecular weight peak, and was therefore strongly influenced by the viscosity term, which is thought to have resulted in a high loss modulus, resulting in a poor wearing comfort.

[0140] The dip-molded product of Comparative Example 4 did not have a low molecular weight peak, and it is thought that the effect of the degree of crosslinking was strong, resulting in a high storage modulus. As a result, the feel of the dip-molded film was poor.

[0141] The dip-molded product of Comparative Example 5 did not have a low molecular weight peak, and the ratio of latex containing a relatively low molecular weight chloroprene polymer was high, which is thought to have resulted in a high storage modulus due to the strong influence of the crosslinking degree and a high loss modulus due to the strong influence of the viscosity term, resulting in a deterioration in the texture and wearing comfort.

[0142] In Comparative Example 6, the chloroprene polymer in the chloroprene polymer latex composition used to obtain the dip-molded product was only a low-molecular-weight chloroprene polymer, and therefore the dip-molded product was brittle and could not have sufficient strength to evaluate each physical property.

[0143] Furthermore, Examples 2-3 and 9 and 10, which used Synthesis Examples B2-B3, B5, and B6, show that the weight-average molecular weight in the low molecular weight region affects the storage modulus, and that the higher the weight-average molecular weight, the higher the storage modulus tends to be. Furthermore, as shown in Example 6, when no vulcanization accelerator or sulfur is added, the storage modulus and loss modulus are slightly lower than those of Example 1, but a dip-molded product having sufficient strength and excellent texture and comfort can be obtained. These results confirm that the dip-molded product of the chloroprene polymer of the present invention has excellent texture regardless of whether a vulcanization accelerator or vulcanization accelerator is added, and exhibits excellent comfort when made into a glove.

Claims

1. A dip-molded product containing a chloroprene polymer, A dip-molded product, wherein the storage modulus E' of the dip-molded product is 3.2 MPa or less and the loss modulus E" of the dip-molded product is 0.37 MPa or less in a frequency range of 10 Hz, as obtained by measuring the dynamic viscoelasticity of the dip-molded product in accordance with a non-resonant forced vibration method under conditions of a static tension of 5 gf, a temperature of 25°C, a strain of 0.75%, and an amplitude of 0.15 mm.

2. 2. The dip-molded article according to claim 1, wherein the chloroprene polymer contains a monomer unit derived from 2,3-dichloro-1,3-butadiene.

3. 3. The dip-molded product according to claim 1, wherein when the dip-molded product is dissolved in tetrahydrofuran and the soluble matter is measured by gel permeation chromatography, at least a peak corresponding to a weight-average molecular weight of 3,000 to 80,000 is detected.

4. The dip-molded product according to claim 1 or claim 2, wherein the dip-molded product comprises a metal oxide.

5. 3. The dip-molded product according to claim 1 or 2, which is an industrial or general household glove, a medical glove, a balloon, a catheter, or a boot.

6. A chloroprene-based polymer, a storage modulus E' of 3.2 MPa or less and a loss modulus E" of 0.37 MPa or less in a frequency range of 10 Hz when a tensile dynamic viscoelasticity measurement is performed in accordance with a non-resonant forced vibration method under conditions of a static tension of 5 gf, a temperature of 25°C, a strain of 0.75%, and an amplitude of 0.15 mm, The dip-molded product is a dip-molded product obtained by molding a chloroprene polymer latex composition containing the chloroprene polymer by a dip coagulation method, and then subjecting the resulting product to a heat drying treatment at 150°C for 60 minutes.

7. A method for producing a dip-molded product containing a chloroprene polymer, comprising: a molding step of molding a chloroprene polymer latex composition containing the chloroprene polymer according to claim 6 using a calcium-based coagulation liquid by a dip coagulation method to obtain a dip-molded product; and The method for producing a dip-molded product includes a drying step of subjecting the obtained dip-molded product to a thermal drying treatment to obtain a dip-molded product.

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