Chloroprene-based block copolymer latex composition, impregnated molded body forming composition, impregnated molded body, and coating composition

Abstract

This invention provides a chloroprene-based block copolymer latex composition with high mechanical stability and low tendency to form aggregates when shear force is applied. Furthermore, when using the chloroprene-based block copolymer latex composition of this invention to prepare compositions for specific applications, compositions with excellent mechanical stability and low tendency to form aggregates when shear force is applied can be obtained (e.g., compositions for impregnation molding, compositions for coatings). According to this invention, a chloroprene-based block copolymer latex composition is provided, comprising a chloroprene-based block copolymer containing a polymer block (A) and a chloroprene-based polymer block (B), wherein the polymer block (A) contains monomer units from a monomer (A), and the monomer (A) is a monomer that, when homopolymerized, yields a polymer with a glass transition temperature of 80°C or higher. In the aforementioned chloroprene-based block copolymer latex composition, the total content of aromatic compounds having 7 to 10 carbon atoms is 0.020 to 0.240 parts by mass relative to 100 parts by mass of the solids component in the aforementioned chloroprene-based block copolymer latex composition.

Description

Technical Field

[0001] This invention relates to chloroprene-based block copolymer latex compositions, compositions for forming dip-molded articles, dip-molded articles, and compositions for coatings. Background Technology

[0002] Compositions containing chloroprene polymers are widely used in various fields such as impregnated molded bodies (impregnated products), fiber treatment agents, paper processing agents, adhesives, bonding agents, elastic bitumen (modified bitumen), and elastic cement.

[0003] For example, various techniques have been proposed for impregnated molded articles containing chloroprene-based polymers. Patent Document 1 describes a polychloroprene latex with a pH of 7-14 for use in impregnated molded articles, which contains 100 parts by weight of modified polychloroprene obtained by copolymerizing chloroprene with methacrylic acid, 90-150 parts by weight of water, 1-5 parts by weight of emulsifier, and 0.5-2.5 parts by weight of potassium ions.

[0004] Existing technical documents

[0005] Patent documents

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2014-114342 Summary of the Invention

[0007] However, conventional compositions containing chloroprene polymers have poor mechanical stability and tend to agglomerate when shear force is applied. The present invention was made in view of these conditions and aims to provide chloroprene block copolymer latex compositions with high mechanical stability and low tendency to agglomerate when shear force is applied. Furthermore, when using the chloroprene block copolymer latex compositions of the present invention to prepare compositions for specific applications, compositions with excellent mechanical stability and low tendency to agglomerate when shear force is applied can be obtained (e.g., compositions for impregnation molding, compositions for coatings).

[0008] [Technical solution used to solve the problem]

[0009] According to the present invention, a chloroprene-based block copolymer latex composition is provided, comprising a chloroprene-based block copolymer containing a polymer block (A) and a chloroprene-based polymer block (B), wherein the polymer block (A) contains monomer units from a monomer (A), and the monomer (A) is a monomer that, when homopolymerized, yields a polymer with a glass transition temperature of 80°C or higher; wherein, in the aforementioned chloroprene-based block copolymer latex composition, the total content of aromatic compounds having 7 to 10 carbon atoms is 0.020 to 0.240 parts by mass relative to 100 parts by mass of the solid components in the aforementioned chloroprene-based block copolymer latex composition.

[0010] Through diligent research, the inventors discovered that in chloroprene-based block copolymer latex compositions containing chloroprene-based block copolymers, by including specific polymer blocks (A) and chloroprene-based polymer blocks (B) in the chloroprene-based block copolymers and by highly adjusting the content of aromatic compounds with 7 to 10 carbon atoms in the chloroprene-based block copolymer latex compositions, mechanical stability can be improved, thereby completing the present invention.

[0011] The following describes various embodiments of the present invention. These embodiments can be combined with each other.

[0012] [1] A chloroprene block copolymer latex composition comprising a chloroprene block copolymer containing a polymer block (A) and a chloroprene polymer block (B), wherein the polymer block (A) contains monomer units from a monomer (A), wherein the monomer (A) is a monomer that can produce a polymer with a glass transition temperature of 80°C or higher when homopolymerized, and wherein, relative to 100 parts by mass of the solid components in the chloroprene block copolymer latex composition, the total content of aromatic compounds having 7 to 10 carbon atoms is 0.020 to 0.240 parts by mass.

[0013] [2] The chloroprene block copolymer latex composition described in [1], wherein the aromatic compound having 7 to 10 carbon atoms comprises at least one selected from the group consisting of toluene, ethylbenzene, cumene, xylene, diethylbenzene, propyltoluene, styrene, and divinylbenzene.

[0014] [3] The chloroprene block copolymer latex composition described in [1] or [2], wherein the content of the polymer block (A) is 7.0 to 15.0% by mass relative to 100% by mass of the aforementioned chloroprene block copolymer.

[0015] [4] A chloroprene block copolymer latex composition as described in any of [1] to [3], wherein the number average molecular weight of the aforementioned polymer block (A) is 14,000 to 30,000.

[0016] [5] A chloroprene block copolymer latex composition as described in any of [1] to [4], wherein the aforementioned polymer block (A) contains monomer units from the aforementioned aromatic compounds having 7 to 10 carbon atoms.

[0017] [6] A composition for forming an impregnated molded body, comprising a chloroprene block copolymer latex composition as described in any one of [1] to [5].

[0018] [7] An impregnation molded body, which is an impregnation molded body of an impregnation molded body forming composition as described in [6].

[0019] [8] A coating composition comprising a chloroprene block copolymer latex composition as described in any one of [1] to [5].

[0020] [Invention Effects]

[0021] The chloroprene-based block copolymer latex composition of the present invention exhibits high mechanical stability, is not prone to agglomeration under shear force, and demonstrates excellent uniform dispersion and storage stability of the chloroprene-based block copolymers in the composition. The chloroprene-based block copolymer latex composition of the present invention can be used to prepare compositions for various applications exhibiting excellent uniform dispersion and storage stability of the chloroprene-based block copolymers. As an example, the chloroprene-based block copolymer latex composition of the present invention can be used in compositions for impregnation molding and compositions for coatings. Detailed Implementation

[0022] The present invention will now be described in detail with reference to embodiments thereof. The present invention is not limited thereto by these descriptions. The various features of the embodiments of the present invention shown below can be combined with each other. Furthermore, each feature constitutes an invention independently.

[0023] 1. Chloroprene-based block copolymer latex composition

[0024] The chloroprene-based block copolymer latex composition of the present invention comprises a chloroprene-based block copolymer containing a polymer block (A) and a chloroprene-based polymer block (B), wherein the polymer block (A) contains monomer units derived from a monomer (A), and the monomer (A) is a monomer that, when homopolymerized, yields a polymer with a glass transition temperature of 80°C or higher. Furthermore, in the aforementioned chloroprene-based block copolymer latex composition, the total content of aromatic compounds having 7 to 10 carbon atoms is 0.020 to 0.240 parts by mass relative to 100 parts by mass of the solids component in the aforementioned chloroprene-based block copolymer latex composition.

[0025] 1.1 Chloroprene-based block copolymers

[0026] 1.1.1 Polymer Block (A)

[0027] The polymer block (A) contains monomer units derived from the monomer (A). That is, in this invention, the raw material monomer of the polymer block (A) includes the monomer (A). The monomer (A) is a monomer that, when homopolymerized, yields a polymer with a glass transition temperature of 80°C or higher. By using such a monomer to form the polymer block, the tensile strength at break of the obtained molded article can be improved. The monomer (A) is preferably a monomer that, when homopolymerized, yields a polymer with a glass transition temperature of 85°C or higher. From the viewpoint of moldability, the monomer (A) is preferably a monomer that, when homopolymerized, yields a polymer with a glass transition temperature of 150°C or lower, and more preferably a monomer that, when homopolymerized, yields a polymer with a glass transition temperature of 120°C or lower. The glass transition temperature of the polymer obtained by homopolymerization of the monomer (A) is, for example, 80, 85, 90, 95, 100, 105, 110, 120, 130, 140, or 150°C, or may be within any range between the values ​​exemplified herein.

[0028] Furthermore, the glass transition temperature in this specification is the extrapolated glass transition termination temperature (Teg) measured according to JIS K 7121. As an example, it can be measured using a differential scanning calorimeter (DSC1 (manufactured by Mettler Toledo)). Specifically, it can be measured using the method described in the examples.

[0029] The monomer (A) is preferably a monomer that has the above-mentioned glass transition temperature when the monomer (A) is homopolymerized to produce a homopolymer (A) with a weight average molecular weight of 10,000 to 100,000. More preferably, it is a monomer that has the above-mentioned glass transition temperature when the homopolymer (A) is homopolymerized to produce a homopolymer (A) with a weight average molecular weight of 14,000 to 30,000.

[0030] Examples of monomer units derived from monomer (A) include aromatic vinyl monomer units and methyl methacrylate monomer units. The polymer block (A) preferably contains aromatic vinyl monomer units, and more preferably contains styrene monomer units.

[0031] In one embodiment of the present invention, the polymer block (A) preferably contains monomer units from aromatic compounds having 7 to 10 carbon atoms. Furthermore, when the chloroprene-based block copolymer latex composition contains a variety of aromatic compounds having 7 to 10 carbon atoms, the polymer block (A) in one embodiment of the present invention may contain any of the aromatic compounds having 7 to 10 carbon atoms selected from the variety of aromatic compounds having 7 to 10 carbon atoms. In one embodiment of the present invention, the total content of aromatic compounds having 7 to 10 carbon atoms in the final chloroprene-based block copolymer latex composition can also be adjusted by highly controlling the polymerization step of the polymer block (A) and adjusting the residual amount of raw material monomers during the polymerization of the polymer block (A).

[0032] The polymer block (A) may contain one or more monomer units derived from the monomer (A). Furthermore, without prejudice to the purpose of the invention, the polymer block (A) may also have monomer units other than those derived from the monomer (A). When the polymer block (A) is set to 100% by mass, the polymer block (A) may contain 70% by mass or more of monomer units derived from the monomer (A). The content of monomer units derived from the monomer (A) may be, for example, 70, 75, 80, 85, 90, 95, or 100% by mass, or may be within any range of the values ​​exemplified herein. The polymer block (A) may also be composed of monomer units derived from the monomer (A).

[0033] From the viewpoint of the mechanical properties and moldability of the obtained chloroprene-based block copolymer, the number average molecular weight of the polymer block (A) can be 10,000 or more, preferably 14,000 or more, and more preferably 14,000 to 30,000. The number average molecular weight of the polymer block (A) is, for example, 10,000, 14,000, 15,000, 20,000, 25,000, 30,000, 35,000, 40,000, 45,000, 50,000, 55,000, 60,000, 65,000, 70,000, 75,000, 80,000, 85,000, 90,000, 95,000, or 100,000, or may be within any range between the values ​​exemplified herein.

[0034] From the viewpoint of the moldability of the obtained chloroprene block copolymer, the molecular weight distribution of the polymer block (A) is preferably 2.00 or less. The molecular weight distribution of the polymer block (A) is, for example, 1.10, 1.20, 1.30, 1.40, 1.50, 1.60, 1.70, 1.80, 1.90, or 2.00, or may be within any range between the values ​​exemplified herein. The number-average molecular weight and molecular weight distribution of the polymer block (A) can be values ​​converted from polystyrene obtained by gel permeation chromatography (GPC), and can be determined using the methods described in the examples.

[0035] The glass transition temperature of the polymer block (A) is, for example, 80, 85, 90, 95, 100, 105, 110, 120, 130, 140, or 150 °C, or any value between any two of the values ​​exemplified herein. The glass transition temperature can be determined using a differential scanning calorimeter (DSC1 (manufactured by Mettler Toledo)), specifically using the method described in the examples.

[0036] 1.1.2 Chloroprene-based polymer block (B)

[0037] The chloroprene-based polymer block (B) of the present invention contains chloroprene monomer units derived from the chloroprene monomer (2-chloro-1,3-butadiene). Furthermore, without prejudice to the purpose of the present invention, the chloroprene-based polymer block (B) may also have a structure derived from monomers other than chloroprene monomers.

[0038] When the chloroprene-based polymer block (B) is set to 100% by mass, the chloroprene-based polymer block (B) of one embodiment of the present invention may contain 70% by mass or more of chloroprene monomer units. The content of chloroprene monomer units may be, for example, 70, 75, 80, 85, 90, 95, or 100% by mass, or may be within any range of the values ​​exemplified herein.

[0039] When the chloroprene-based polymer block (B) is set to 100% by mass, the chloroprene-based polymer block (B) of one embodiment of the present invention may contain less than 30% by mass of monomer units other than the chloroprene monomer unit. The content of monomer units other than the chloroprene monomer unit may be, for example, 0, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, or 30% by mass, or may be within any range between the values ​​exemplified herein.

[0040] Other monomer units besides the chloroprene monomer unit can include, for example, unsaturated nitriles such as 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, styrene, isoprene, butadiene, acrylonitrile, methacrylonitrile, and polyfunctional monomers. The polyfunctional monomer can be a compound having two or more free radical polymeric groups in its molecule. The polyfunctional monomer can have multiple polymerizable substituents that are independent of each other. The polyfunctional monomer can have at least one set of non-conjugated polymerizable substituents, and at least one set of polymerizable substituents can be spaced apart by at least one atom, three or more atoms, or five or more atoms. The polymerizable substituents can be vinyl groups or carbon-carbon double bonds. From the viewpoint of the flexibility, tensile strength at break, and moldability of the obtained chloroprene-based block copolymer, the polyfunctional monomer unit of one embodiment of the present invention is preferably a monomer unit represented by chemical formula (1) or an aromatic polyene monomer unit.

[0041] [Chemistry 1]

[0042]

[0043] In chemical formula (1), R1 and R2 each independently represent any one of hydrogen, chlorine, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted mercapto, or substituted or unsubstituted heterocyclic group. W1 represents any one of saturated or unsaturated hydrocarbon group, saturated or unsaturated cyclic hydrocarbon group, saturated or unsaturated hydrocarbon group containing heteroatoms, or saturated or unsaturated cyclic hydrocarbon group containing heteroatoms. Z1 represents oxygen, sulfur, or the structure represented by -NR0-. R0 represents any one of hydrogen, chlorine, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted mercapto, or substituted or unsubstituted heterocyclic group.

[0044] Monomers represented by chemical formula (1) include 1,9-nonanediol dimethacrylate, 1,9-nonanediol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, 1,6-hexanediol dimethacrylate, 1,6-hexanediol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, N,N'-diacetyl-4,7,10-trioxa-1,13-tetanediamine. Aromatic polyene monomers include aromatic polyenes having 10 to 30 carbon atoms and possessing multiple double bonds (vinyl groups) and one or more aromatic groups. Examples of aromatic polyene monomers include o-divinylbenzene, p-divinylbenzene, m-divinylbenzene, 1,4-divinylnaphthalene, 3,4-divinylnaphthalene, 2,6-divinylnaphthalene, 1,2-divinyl-3,4-dimethylbenzene, and 1,3-divinyl-4,5,8-tributylnaphthalene. Preferably, one or a mixture of two or more of o-divinylbenzene, p-divinylbenzene, and m-divinylbenzene are used.

[0045] In one embodiment of the present invention, when the chloroprene-based polymer block (B) contains monomer units from a multifunctional monomer, the monomer units from the multifunctional monomer may include monomer units from aromatic compounds having 7 to 10 carbon atoms. Furthermore, in another embodiment of the present invention, when the chloroprene-based polymer block (B) contains monomer units from a multifunctional monomer, the monomer units from the multifunctional monomer may include aromatic polyene monomer units, and the aromatic polyene monomer may include monomer units from aromatic compounds having 7 to 10 carbon atoms. Moreover, when the chloroprene-based block copolymer latex composition contains multiple aromatic compounds having 7 to 10 carbon atoms, the multifunctional monomer unit in one embodiment of the present invention may include any of the multiple aromatic compounds having 7 to 10 carbon atoms. In one embodiment of the present invention, the total content of aromatic compounds with carbon numbers of 7 to 10 in the final chloroprene block copolymer latex composition can also be adjusted by highly controlling the polymerization steps of the chloroprene block copolymer and adjusting the residual amount of raw material monomers during the polymerization of the chloroprene polymer block (B).

[0046] Furthermore, the multifunctional monomer may not contain 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, styrene, acrylonitrile, methacrylonitrile, isoprene, or butadiene. Additionally, the chloroprene-based polymer block (B) of one embodiment of the present invention may not contain 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, styrene, acrylonitrile, methacrylonitrile, isoprene, or butadiene. The chloroprene-based polymer block (B) of one embodiment of the present invention may not contain monomer units derived from the multifunctional monomer.

[0047] 1.1.3 Content of each component in the chloroprene block copolymer

[0048] In one embodiment of the present invention, the chloroprene-based block copolymer preferably contains 7.0 to 15.0% by mass of polymer block (A) relative to 100% by mass of the chloroprene-based block copolymer. The content of polymer block (A) can be, for example, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0, or 15.0% by mass, or may be within any range of the values ​​exemplified herein. If the content of polymer block (A) is above the lower limit mentioned above, the tensile strength at break of the impregnated molded article containing the obtained chloroprene-based block copolymer is further improved. If the content of polymer block (A) is below the upper limit mentioned above, the elongation at break of the impregnated molded article containing the obtained chloroprene-based block copolymer is further improved.

[0049] A chloroprene-based block copolymer of one embodiment of the present invention preferably contains 85-97% by mass of chloroprene polymer blocks (B) relative to 100% by mass of the chloroprene-based block copolymer, for example, it may contain 85, 90, 95, 96, or 97% by mass, or any value between any two of the values ​​exemplified herein. A chloroprene-based block copolymer of one embodiment of the present invention preferably contains a total of 70-100% by mass of polymer blocks (A) and chloroprene polymer blocks (B) relative to 100% by mass of the chloroprene-based block copolymer, for example, 70, 75, 80, 85, 90, 95, or 100% by mass, or any value between any two of the values ​​exemplified herein.

[0050] In one embodiment of the present invention, the chloroprene-based block copolymer may be composed of polymer block (A) and chloroprene-based polymer block (B), and may not contain other polymer blocks. The chloroprene-based block copolymer may be a diblock copolymer of polymer block (A) and chloroprene-based polymer block (B).

[0051] In addition, the chloroprene block copolymer of one embodiment of the present invention may have functional groups with structures represented by chemical formula (2) or chemical formula (3).

[0052] [Chemistry 2]

[0053]

[0054] In chemical formula (2), R3 represents any one of hydrogen, chlorine, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted mercapto, or substituted or unsubstituted heterocyclic group.

[0055] [Chemistry 3]

[0056]

[0057] The functional groups of the structure represented by chemical formula (2) or chemical formula (3) can be introduced by a polymerization step of a chloroprene block copolymer in the presence of a RAFT agent (e.g., polymerization step 1 and / or polymerization step 2 described later). Compounds that can be used to introduce the functional groups of the structure represented by chemical formula (2) or chemical formula (3) will be described in the method of manufacture section.

[0058] There is no particular limitation on the weight-average molecular weight of chloroprene block copolymers, but from the viewpoint of molding and processability, it is preferably 500,000 to 600,000, and particularly preferably 100,000 to 500,000.

[0059] 1.1.4 Aromatic compounds with 7 to 10 carbon atoms

[0060] The chloroprene-based block copolymer latex composition of the present invention contains aromatic compounds having 7 to 10 carbon atoms.

[0061] Aromatic compounds with 7 to 10 carbon atoms include toluene, o-xylene, m-xylene, p-xylene, styrene, ethylbenzene, 2-ethyltoluene, 3-ethyltoluene, 4-ethyltoluene, cumene, 2-propyltoluene, 3-propyltoluene, 4-propyltoluene, 1,2-diethylbenzene, 1,3-diethylbenzene, 1,4-diethylbenzene, o-divinylbenzene, p-divinylbenzene, and m-divinylbenzene.

[0062] Aromatic compounds with 7 to 10 carbon atoms may include aromatic compounds in which one or more hydrogen atoms are substituted by hydroxyl, amino, nitro, carbonyl, carboxyl, isocyanate, or the like. Additionally, aromatic compounds with 7 to 10 carbon atoms may also include aromatic compounds in which one or more hydrogen atoms are substituted by halogens (chlorine, bromine, iodine, fluorine). Aromatic compounds with 7 to 10 carbon atoms may also include aromatic compounds containing 6 carbon atoms before substitution and substituted by carbon-containing substituents (e.g., salicylic acid, acetophenone). In one embodiment of the present invention, an aromatic compound with 7 to 10 carbon atoms may include at least one from the group consisting of toluene, ethylbenzene, cumene, xylene, diethylbenzene, propyltoluene, styrene, divinylbenzene, and aromatic compounds in which one or more hydrogen atoms are substituted, and may include at least one from the group consisting of toluene, ethylbenzene, cumene, xylene, diethylbenzene, propyltoluene, styrene, and divinylbenzene. An aromatic compound having 7 to 10 carbon atoms according to one embodiment of the present invention may comprise at least one compound from the group consisting of toluene, ethylbenzene, xylene, styrene, divinylbenzene, and aromatic compounds in which one hydrogen atom is substituted, and may comprise at least one compound from the group consisting of toluene, ethylbenzene, xylene, styrene, and divinylbenzene. An aromatic compound having 7 to 10 carbon atoms according to one embodiment of the present invention may comprise at least one compound from the group consisting of toluene, xylene, styrene, ethylbenzene, and aromatic compounds in which one hydrogen atom is substituted, and may comprise at least one compound from the group consisting of toluene, xylene, styrene, and ethylbenzene.

[0063] The number of carbon atoms in the aromatic compound having 7 to 10 carbon atoms in one embodiment of the present invention is, for example, 7, 8, 9, or 10, or may be within any range of the values ​​exemplified herein. The molecular weight of the aromatic compound having 7 to 10 carbon atoms in one embodiment of the present invention can be 80 to 135. The molecular weight of the aromatic compound having 7 to 10 carbon atoms in one embodiment of the present invention is, for example, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, or 135, or may be within any range of the values ​​exemplified herein.

[0064] In the chloroprene-based block copolymer latex composition of the present invention, the total content of aromatic compounds with 7 to 10 carbon atoms is 0.020 to 0.240 parts by mass relative to 100 parts by mass of solid components in the chloroprene-based block copolymer latex composition. The total content of aromatic compounds with 7 to 10 carbon atoms, relative to 100 parts by weight of solids in the chloroprene block copolymer latex composition, is, for example, 0.020, 0.030, 0.040, 0.050, 0.060, 0.070, 0.080, 0.090, 0.100, 0.110, 0.120, 0.130, 0.140, 0.150, 0.160, 0.170, 0.180, 0.190, 0.200, 0.210, 0.220, 0.230, or 0.240 parts by weight, or any two of the values ​​exemplified herein.

[0065] It is speculated that in the chloroprene block copolymer latex composition of the present invention, the total content of aromatic compounds with 7 to 10 carbon atoms relative to 100 parts by mass of solid components in the chloroprene block copolymer latex composition is adjusted to a very high degree. Therefore, the dispersibility of the chloroprene block copolymer in the chloroprene block copolymer latex composition is improved, and it has excellent mechanical stability. In addition, when preparing compositions for specific purposes using the chloroprene block copolymer latex composition of the present invention, since the resulting composition (e.g., a composition for impregnation molding, a composition for coating) contains a chloroprene block copolymer latex composition with the total content of the aforementioned aromatic compounds with 7 to 10 carbon atoms adjusted to a very high degree, a composition is prepared in which the chloroprene block copolymer and various reagents contained in each composition (e.g., crosslinking agents, lipophilic agents, etc.) are uniformly dispersed, thereby improving the mechanical stability of compositions for impregnation molding, etc. For example, a composition for forming an impregnated molded article containing the chloroprene-based block copolymer latex composition of the present invention exhibits excellent mechanical stability due to the uniform dispersion of each component in the composition. Furthermore, the mechanical properties of the impregnated molded article made from this composition are improved, including tensile strength at break and elongation at break, and it possesses a moderate stress at 500% elongation. Additionally, a coating composition containing the chloroprene-based block copolymer latex composition of the present invention exhibits excellent mechanical stability due to the uniform dispersion of each component in the composition. Therefore, it can form a coating film (molded article) with excellent storage stability, as well as excellent tensile strength at break, elongation at break, and a moderate stress at 500% elongation.

[0066] The content of aromatic compounds with 7 to 10 carbon atoms relative to 100 parts by mass of solids in a chloroprene block copolymer latex composition can be analyzed by gas chromatography, and can be specifically calculated using the methods described in the examples.

[0067] The total content of aromatic compounds with carbon numbers 7 to 10 relative to 100 parts by mass of solid components in a chloroprene block copolymer latex composition can be adjusted by adding aromatic compounds with carbon numbers 7 to 10 to the chloroprene block copolymer latex. Furthermore, when the raw materials used in the polymerization of the chloroprene block copolymer latex contain aromatic compounds with carbon numbers 7 to 10, or when aromatic compounds with carbon numbers 7 to 10 may be generated as byproducts during the manufacture of the chloroprene block copolymer, the content of aromatic compounds with carbon numbers 7 to 10 can be controlled by adjusting the polymerization conditions of the chloroprene block copolymer (e.g., adjusting the amount and timing of initiator addition) and the manufacturing conditions of the chloroprene polymer (including latex concentration and dilution conditions), etc., of the chloroprene block copolymer latex composition.

[0068] In one embodiment of the chloroprene-based block copolymer latex composition of the present invention, the total content of 4-chlorovinylbenzene, 2-methylbenzyl chloride, and 3-methylbenzyl chloride is preferably 0.00100 parts by mass or less relative to 100 parts by mass of solids in the chloroprene-based block copolymer latex composition. The total content of 4-chlorovinylbenzene, 2-methylbenzyl chloride, and 3-methylbenzyl chloride relative to 100 parts by mass of solids in the chloroprene-based block copolymer latex composition is, for example, 0, 0.00010, 0.00020, 0.00030, 0.00040, 0.00050, 0.00060, 0.00070, 0.00080, 0.00090, or 0.00100 parts by mass, or may be within any range between the values ​​exemplified herein. In a chloroprene-based block copolymer latex composition according to one embodiment of the present invention, the total content of compounds in which one or more hydrogen atoms bonded to an aromatic ring are replaced by chlorine atoms or chlorine-containing substituents, relative to 100 parts by mass of solid components in the chloroprene-based block copolymer latex composition, is within the above-mentioned numerical range, and the total content of compounds in which one or more hydrogen atoms bonded to an aromatic ring are replaced by halogens or halogen-containing substituents is within the above-mentioned numerical range.

[0069] A chloroprene-based block copolymer latex composition according to one embodiment of the present invention may not contain 4-chlorovinylbenzene, 2-methylbenzyl chloride, 3-methylbenzyl chloride, and 4-methylbenzyl chloride, and may not contain compounds in which one or more hydrogen atoms bonded to the aromatic ring are replaced by chlorine atoms, or compounds in which chlorine-containing substituents are substituted. Furthermore, a chloroprene-based block copolymer latex composition according to one embodiment of the present invention may not contain compounds in which one or more hydrogen atoms bonded to the aromatic ring are replaced by halogens, or compounds in which halogen-containing substituents are substituted.

[0070] As an example, the content of these chlorine-containing compounds can be controlled by appropriately controlling the polymerization conditions of chloroprene block copolymers to suppress the formation of byproducts.

[0071] The chloroprene-based block copolymer latex composition of one embodiment of the present invention has a preferred agglomerate generation rate (mechanical stability) of 2.0% by mass when the solid component concentration is adjusted to 50% by mass and a shear force of 10 kg and 1000 rpm is applied for 10 minutes.

[0072] The agglomeration rate of the chloroprene-based block copolymer latex composition is, for example, 0, 0.50, 1.00, 1.50, or 2.00% by mass, or any value between two of the values ​​exemplified here. If the agglomeration rate of the chloroprene-based block copolymer latex composition is within the above-mentioned range, the mechanical stability of various compositions containing the chloroprene-based block copolymer latex composition is further improved. For example, the mechanical properties such as tensile strength at break and elongation at break of the impregnated molded body made using the impregnated molded body forming composition are further improved, and it has a suitable stress at 500% elongation.

[0073] The agglomerate formation rate can be expressed by the following formula, which can be specifically determined using the method described in the examples.

[0074] Agglomerate formation rate (mechanical stability) (mass %) = Dry mass of aggregate [g] / Mass of solids component of chloroprene block copolymer latex composition [g] × 100

[0075] The agglomerate formation rate of chloroprene block copolymer latex compositions can be controlled, for example, by adjusting the polymerization conditions of the chloroprene block copolymer latex, the presence or absence of aromatic compounds with 7 to 10 carbon atoms in the chloroprene block copolymer latex, or the amount of such compounds added, thereby adjusting the total content of aromatic compounds with 7 to 10 carbon atoms.

[0076] In one embodiment of the present invention, when preparing a test impregnation molding composition containing 2 parts by mass of the butylation reaction product of p-cresol and dicyclopentadiene and 0.1 parts by mass of the sodium salt of the β-naphthalenesulfonic acid formalin condensate relative to 100 parts by mass of the solid component of the chloroprene block copolymer latex composition, the agglomerate generation rate (mechanical stability) generated when a shear force of 10 kg and 1000 rpm is applied to the test impregnation molding composition for 10 minutes is preferably 2.0% by mass or less.

[0077] The agglomeration rate of the impregnation molding composition used in the experiment is, for example, 0, 0.50, 1.00, 1.50, or 2.00% by mass, or any value between two of the values ​​exemplified here. If the agglomeration rate of the impregnation molding composition is within the above-mentioned range, the uniformity, dispersibility, and stability of the impregnation molding composition itself are improved, and the mechanical properties of the impregnation molded body made from this impregnation molding composition, such as tensile strength at break and elongation at break, are further improved, and it has a suitable stress at 500% elongation.

[0078] As for the evaluation method of the agglomerate generation rate, the method for determining the mechanical stability of the impregnation molding composition described in the examples can be used.

[0079] The agglomerate generation rate of the composition for impregnation molding can be controlled, for example, by adjusting the manufacturing conditions of the chloroprene block copolymer latex, the presence or absence of aromatic compounds with 7 to 10 carbon atoms added to the chloroprene block copolymer latex, or the amount of such compounds added, to adjust the total content of aromatic compounds with 7 to 10 carbon atoms, thereby adjusting the agglomerate generation rate of the chloroprene block copolymer latex composition.

[0080] According to one embodiment of the present invention, the chloroprene-based block copolymer latex composition is prepared by impregnating and molding the above-prepared test impregnation molding composition using an impregnation coagulation method, and then drying it at 130°C for 30 minutes. The tensile strength at break of the resulting impregnated molded body is preferably 17.5 MPa or higher. Specific tensile strengths at break of the impregnated molded body include, for example, 17.5, 18.0, 19.0, 20.0, 21.0, 22.0, 23.0, 24.0, 25.0, 26.0, 27.0, 28.0, 29.0, and 30.0 MPa, or may be within any range of the values ​​exemplified herein.

[0081] According to one embodiment of the present invention, a chloroprene-based block copolymer latex composition is prepared by impregnating and curing the above-prepared test impregnation molding composition using an impregnation coagulation method, and then drying it at 130°C for 30 minutes. The elongation at break of the resulting impregnated molded body is preferably 800% or more. The elongation at break of the impregnated molded body is, for example, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, or 1700%, or may be within any range between the values ​​exemplified herein.

[0082] In one embodiment of the present invention, a chloroprene-based block copolymer latex composition is prepared by impregnating and curing the above-mentioned experimental impregnation molding composition using an impregnation coagulation method, and then drying it at 130°C for 30 minutes. The stress at 500% elongation of the resulting impregnated molded body is preferably 4.0 MPa or less. The stress at 500% elongation of the impregnated molded body is, for example, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, or 4.0 MPa, or may be within any range of the values ​​exemplified herein.

[0083] Tensile strength at break, elongation at break, and stress at 500% elongation can be measured according to JIS K 6251, and can be evaluated using the methods described in the examples.

[0084] The chloroprene-based block copolymer latex composition of one embodiment of the present invention has excellent uniform dispersibility and excellent mechanical stability due to the excellent uniform dispersibility and mechanical stability of the chloroprene-based block copolymer. Therefore, when preparing compositions for specific applications such as impregnation molding compositions and coating compositions, it is possible to obtain compositions in which the chloroprene-based block copolymer and various reagents (e.g., crosslinking agents, lipophilic agents, etc.) contained in each composition are uniformly dispersed. Impregnation molding articles and coating films (molded articles) made from impregnation molding compositions and coating compositions containing the chloroprene-based block copolymer latex composition of one embodiment of the present invention have excellent tensile strength at break, elongation at break, and moderate stress at 500% elongation. Therefore, these properties can be utilized to make them suitable for various parts that require excellent tensile strength at break, elongation at break, and / or moderate stress at 500% elongation. As an example, the coating composition of one embodiment of the present invention can be used particularly as an automotive coating or intermediate coating, and can form a coating film (molded body) with excellent tensile strength at break, elongation at break, and / or moderate stress at 500% elongation. Furthermore, as an example, the intermediate coating can be a mid-coat coating that can be applied over a base coating, and can be further coated with a base coating or top coating for use.

[0085] 2. Method for manufacturing chloroprene-based block copolymer latex compositions

[0086] The method for manufacturing the chloroprene-based block copolymer latex composition of the present invention is not particularly limited, and can be obtained, for example, by the following manufacturing method. The method for manufacturing the chloroprene-based block copolymer latex composition of the present invention may include: a polymerization step 1, polymerizing a raw material monomer containing monomer (A) to obtain a polymer block (A); and a polymerization step 2, polymerizing a raw material monomer containing chloroprene to obtain a chloroprene-based block copolymer latex containing a chloroprene-based polymer block (B), which can be manufactured by a manufacturing method including a two-stage polymerization step.

[0087] The polymerization method is not particularly limited, and known methods such as solution polymerization, emulsion polymerization, and bulk polymerization can be used, with emulsion polymerization being preferred. In each polymerization step, emulsifiers or dispersants, polymerization initiators, RAFT agents, reducing agents, etc., can be appropriately used to emulsify and polymerize the raw monomers. Furthermore, in polymerization step 2, when the target polymerization rate is reached, a polymerization terminator can be added to obtain a chloroprene-based block copolymer latex. After the polymerization step, unreacted monomers can be removed using concentration methods such as vacuum distillation. Moreover, the method for manufacturing the chloroprene-based block copolymer latex composition according to one embodiment of the present invention may also include a step of adding an aromatic compound with 7 to 10 carbon atoms to the chloroprene-based block copolymer latex containing the chloroprene-based block copolymer.

[0088] <Aggregation Step 1>

[0089] In polymerization step 1, the raw material monomer containing monomer (A) can be polymerized to obtain polymer block (A). In one embodiment of the present invention, the raw material monomer containing monomer (A) can be subjected to living radical polymerization to synthesize polymer block (A). Preferably, the raw material monomer is formulated such that the composition of polymer block (A) is as described above, and the type and amount of monomer (A) in polymer block (A) are as described above. In addition, the glass transition temperature of the polymer block (A) obtained here is, for example, 80, 85, 90, 95, 100, 105, 110, 120, 130, 140, 150°C, or any value between the two values ​​exemplified here.

[0090] (Emulsifier)

[0091] The emulsifier used in the polymerization is not particularly limited, but from the viewpoint of emulsification stability, anionic and / or nonionic emulsifiers are preferred. Rosin acid and / or alkali metal salts of rosin acid are particularly preferred, as they impart appropriate strength to the resulting chloroprene block copolymers to prevent excessive shrinkage and breakage. From the viewpoint of efficiently carrying out the polymerization reaction, the concentration of the emulsifier can be 5 to 50 parts by weight relative to 100 parts by weight of the starting monomer.

[0092] The emulsifier may also include emulsifiers or dispersants other than rosin acid and basal metal salts of rosin acid. In one embodiment of the present invention, the emulsifier used in the emulsification polymerization step may include rosin acid and / or basal metal salts of rosin acid, as well as anionic emulsifiers or dispersants. As anionic emulsifiers or dispersants, from the viewpoint of stabilizing chloroprene block copolymer latex when adding pH adjusters, sulfate-based or sulfonate-based anionic emulsifiers or dispersants are preferred. Specifically, examples include alkyl sulfonates with 8 to 20 carbon atoms, alkyl aryl sulfates, condensates of sodium naphthalene sulfonate and formaldehyde, and sodium alkyl diphenyl ether disulfonate.

[0093] (Initiator)

[0094] The initiator can be a free radical polymerization initiator. Well-known free radical polymerization initiators can be used, such as potassium persulfate, benzoyl peroxide, hydrogen peroxide, and azo compounds.

[0095] In polymerization step 1 of one embodiment of the present invention, an initiator may be added in, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.0 parts by mass relative to 100 parts by mass of the raw material monomer. The amount of initiator added may also be within any range between the values ​​exemplified herein.

[0096] In polymerization step 1 of one embodiment of the present invention, the initiator can be added in multiple stages. Besides the initial addition at the start of polymerization, the initiator can also be added subsequently after polymerization begins. The number of additional additions can be at least one or more times, or more than two times. Continuous addition includes adding the initiator at a constant flow rate.

[0097] In polymerization step 1 of one embodiment of the present invention, the additional amount of initiator added relative to 100% by mass of the initiator used in polymerization step 1 is, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20% by mass, or may be within any range between the values ​​exemplified herein.

[0098] In polymerization step 1 of one embodiment of the present invention, the timing of adding the initiator can be when the polymerization rate reaches, for example, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99%, or within any range between the values ​​exemplified herein. In polymerization step 1 of one embodiment of the present invention, the amount of raw material monomers in the latex of the resulting block polymer (A) can be adjusted by highly controlling the polymerization process through the addition of the initiator.

[0099] (RAFT agent)

[0100] In one embodiment of the present invention, a RAFT agent can be used in the manufacturing method. By polymerizing in the presence of a known RAFT agent, the end structure represented by chemical formula (2) or chemical formula (3) can be introduced into the chloroprene block copolymer.

[0101] [Chemistry 2]

[0102]

[0103] In chemical formula (2), R3 represents any one of hydrogen, chlorine, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted mercapto, or substituted or unsubstituted heterocyclic group.

[0104] [Chemistry 3]

[0105]

[0106] There are no particular limitations on the compounds that form the structure represented by the above chemical formula (3). Common compounds can be used, such as dithiocarbamates and dithioesters. Specifically, examples include: benzyl 1-pyrrole dithiocarbamate (common name: 1-pyrrole dithiocarbamate), benzyl phenyl dithiocarbamate, 1-benzyl-N,N-dimethyl-4-aminodithiobenzoate, 1-benzyl-4-methoxydithiobenzoate, 1-phenylethylimidazolium dithiocarbamate (common name: 1-phenylethylimidazolium dithiocarbamate), benzyl-1-(2-pyrrolidinone)dithiocarbamate (common name: benzyl-1-(2-pyrrolidinone)dithiocarbamate), benzyl phthalimide dithiocarbamate (common name: benzyl phthalimide dithiocarbamate), 2-cyanopropyl-2-yl -1-Pyrrole dithiocarbamate (common name: 2-cyanopropyl-2-yl-1-pyrrole dithiocarbamate), 2-cyanobutyl-2-yl-1-pyrrole dithiocarbamate (common name: 2-cyanobutyl-2-yl-1-pyrrole dithiocarbamate), benzyl-1-imidazolium dithiocarbamate (common name: benzyl-1-imidazolium dithiocarbamate), 2-cyanopropyl-2-yl-N,N-dimethyl dithiocarbamate, benzyl-N,N-diethyl dithiocarbamate, cyanomethyl-1-(2-pyrrolidone) dithiocarbamate, 2-(ethoxycarbonylbenzyl)propyl-2-yl-N,N-diethyl dithiocarbamate, 1- Phenylacetyl dithiobenzoate, 2-phenylprop-2-yl dithiobenzoate, 1-acetic-1-yl-ethyl dithiobenzoate, 1-(4-methoxyphenyl)ethyl dithiobenzoate, benzyl dithioacetate, ethoxycarbonylmethyl dithioacetate, 2-(ethoxycarbonyl)prop-2-yl dithiobenzoate, 2-cyanoprop-2-yl dithiobenzoate, tert-butyl dithiobenzoate, 2,4,4-trimethylpentane-2-yl dithiobenzoate, 2-(4-chlorophenyl)prop-2-yl dithiobenzoate, 3-vinylbenzyl dithiobenzoate, 4-vinylbenzyl dithiobenzoate, benzyl diethoxyphosphine dithiobenzoate Formate esters, tert-butyl trithiobenzoate, 2-phenylpropyl-2-yl-4-chlorodithiobenzoate, 1-methyl-1-phenyl-ethyl naphthalene-1-carboxylic acid, 4-cyano-4-methyl-4-thiobenzylthioalkylbutyric acid, dibenzyl tetrathiophthalate, carboxymethyl dithiobenzoate, poly(ethylene oxide) with dithiobenzoate terminal groups, poly(ethylene oxide) with 4-cyano-4-methyl-4-thiobenzylthioalkylbutyric acid terminal groups, 2-[(2-phenylethylthio)thioalkyl]propionic acid, 2-[(2-phenylethylthio)thioalkyl]succinic acid, potassium 3,5-dimethyl-1H-pyrazole-1-dithiocarboxylate, cyanomethyl-3,5-Dimethyl-1H-pyrazole-1-dithiocarbamate, cyanomethyl-N-methyl-N-phenyl dithiocarbamate, benzyl-4-chlorodithiocarbamate, phenylmethyl-4-chlorodithiocarbamate, 4-nitrobenzyl-4-chlorodithiocarbamate, phenylpropyl-2-yl-4-chlorodithiocarbamate, 1-cyano-1-methylethyl-4-chlorodithiocarbamate, 3-chloro-2-butenyl-4-chlorodithiocarbamate, 2-chloro-2-butenyldithiocarbamate, benzyl dithioacetate, 3-chloro-2-butenyl-1H-pyrrole-1-dithiocarboxylic acid, 2-cyanobutyl-2-yl-4-chloro-3,5-dimethyl-1H-pyrazole-1-dithiocarbamate, cyanomethylmethyl(phenyl)aminodithiocarbamate. Among them, benzyl 1-pyrrole dithiocarbamate and benzyl phenyl dithiocarbamate are particularly preferred.

[0107] The compound forming the structure represented by the above chemical formula (2) is not particularly limited and can be a general compound, such as: 2-cyano-2-propyldodecyl trithiocarbonate, dibenzyl trithiocarbonate, butyl benzyl trithiocarbonate, 2-[[(butylthio)thiomethyl]thio]propionic acid, 2-[[(dodecylthio)thiomethyl]thio]propionic acid, 2-[[(butylthio)thiomethyl]thio]succinic acid, 2-[[(dodecyl ...]thiomethyl]thio]succinic acid, 2-[[(dodecylthio]thiomethyl]thio]succinic acid, 2-[[(dodecylthio]thiomethyl]thio]succinic acid, 2-[[(dodecylthio]thiomethyl]thio Trithiocarbonates include alkylthio[thiomethyl]thio[2-methylpropionic acid, 2,2'-[carbonthioylbis(thio)]bis[2-methylpropionic acid], 2-amino-1-methyl-2-oxoethylbutyl trithiocarbonate, benzyl 2-[(2-hydroxyethyl)amino]-1-methyl-2-oxoethyl trithiocarbonate, 3-[[[(tert-butyl)thio]thiomethyl]thio]propionic acid, cyanomethyl dodecyl trithiocarbonate, diethylaminobenzyl trithiocarbonate, and dibutylaminobenzyl trithiocarbonate. Dibenzyl trithiocarbonate and butyl benzyl trithiocarbonate are particularly preferred.

[0108] The amount of RAFT agent added relative to 100 parts by weight of raw material monomer can be 0.1 to 10 parts by weight, for example, 0.1, 0.2, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts by weight, or any two of the values ​​exemplified here.

[0109] Sodium hydroxide and / or potassium hydroxide can be used in the polymerization step. Additionally, a reducing agent can be added during the polymerization step. Examples of reducing agents include potassium metabisulfite, potassium sulfite, potassium bisulfite, potassium phosphate, potassium hydrogen phosphate, sodium bisulfite, sodium sulfate, and thiourea dioxide.

[0110] (Aggregation Conditions)

[0111] The polymerization temperature can be appropriately determined according to the type of monomer, preferably 10 to 100°C, and particularly preferably 20 to 80°C.

[0112] <Aggregation Step 2>

[0113] In polymerization step 2, by adding raw material monomers containing chloroprene monomers (and other monomers such as multifunctional monomers as needed) to the latex containing polymer blocks (A) obtained in polymerization step 1 and then polymerizing, a chloroprene block copolymer latex containing chloroprene polymer blocks (B) can be obtained. The raw material monomers can be added all at once, or initially and subsequently. Preferably, the type and amount of each monomer are adjusted so that the content of each monomer unit in the resulting chloroprene polymer blocks (B) and chloroprene block copolymers falls within the aforementioned numerical range.

[0114] From the viewpoint of easy control of polymerization, the polymerization temperature in polymerization step 2 is preferably 10–50°C. The polymerization reaction is terminated by adding a polymerization terminator. Examples of polymerization terminators include thiodiphenylamine, 4-tert-butylcatechol, and 2,2'-methylenebis-4-methyl-6-tert-butylphenol. Unreacted monomers after polymerization can be removed using common methods, such as vacuum distillation.

[0115] In the latex containing chloroprene block copolymers obtained in polymerization step 2, freeze stabilizers, emulsion stabilizers, viscosity modifiers, antioxidants, preservatives, etc., may be added arbitrarily after polymerization without compromising the purpose of this invention.

[0116] The chloroprene block copolymer latex of one embodiment of the present invention may comprise the aforementioned chloroprene block copolymer and water. The liquid at the end of polymerization obtained by the polymerization method described in the above manufacturing method can be used directly as a chloroprene block copolymer latex. When the chloroprene block copolymer latex of the present invention is obtained by emulsification polymerization, the chloroprene block copolymer latex may also comprise raw materials used in the emulsification polymerization step, such as emulsifiers.

[0117] Alternatively, chloroprene-based block copolymers can be recovered from latex containing chloroprene-based block copolymers, and the recovered chloroprene-based block copolymers can be forcibly emulsified using an emulsifier to obtain chloroprene-based block copolymer latex. There are no particular limitations on the method for recovering chloroprene-based block copolymers from latex containing chloroprene-based block copolymers; known methods such as immersion in a coagulation solution for recovery or precipitation using unsuitable solvents such as methanol can be used.

[0118] One embodiment of the manufacturing method of the present invention may include a concentration step in which the above-mentioned chloroprene block copolymer latex is concentrated using methods such as vacuum distillation. Through the concentration step, unreacted monomers can be removed, and the solid content concentration of the chloroprene block copolymer latex can be adjusted. One embodiment of the manufacturing method of the present invention may include one or more concentration steps. The concentration steps may be, for example, 1, 2, 3, 4, or 5 times, or may be within any range of the values ​​exemplified herein.

[0119] One embodiment of the manufacturing method of the present invention may include a dilution step of adding water to the aforementioned chloroprene-based block copolymer latex, which can dilute the concentration of each component in the chloroprene-based block copolymer latex and adjust the concentration of the solid components of the chloroprene-based block copolymer latex. One embodiment of the manufacturing method of the present invention may include one or more dilution steps. The dilution steps may be, for example, 1, 2, 3, 4, or 5 times, or may be within any range of the values ​​exemplified herein.

[0120] When the raw materials used in the polymerization of chloroprene block copolymers may contain aromatic compounds with 7 to 10 carbon atoms, or when aromatic compounds with 7 to 10 carbon atoms may be generated as byproducts during the manufacture of chloroprene block copolymers, the content of aromatic compounds with 7 to 10 carbon atoms can be controlled by adjusting the concentration conditions or number of concentrations, and the dilution conditions or number of dilutions of the chloroprene block copolymer latex.

[0121] (Concentration of solid components)

[0122] There is no particular limitation on the solid content concentration of chloroprene block copolymer latex, which can be adjusted to 40-65% by mass. The solid content concentration of chloroprene block copolymer latex can be controlled by adjusting the proportion of solvents such as water during the emulsification polymerization of chloroprene block copolymers, or by concentration and dilution steps.

[0123] A method for manufacturing a chloroprene-based block copolymer latex composition according to one embodiment of the present invention may include an aromatic compound addition step of adding an aromatic compound with 7 to 10 carbon atoms to the chloroprene-based block copolymer latex.

[0124] The types of aromatic compounds added as aromatic compounds are as described above. In the aromatic compound addition step, aromatic compounds having 7 to 10 carbon atoms may be added such that the total content of aromatic compounds having 7 to 10 carbon atoms relative to 100 parts by mass of the solid components in the resulting chloroprene block copolymer latex composition is within the aforementioned numerical range. As an example, in the aromatic compound addition step, a total of 0.020 to 0.240 parts by mass of aromatic compounds having 7 to 10 carbon atoms are added relative to 100 parts by mass of the solid components in the chloroprene block copolymer latex composition. The total amount of aromatic compounds having 7 to 10 carbon atoms added is, for example, 0.020, 0.030, 0.040, 0.050, 0.060, 0.070, 0.080, 0.090, 0.100, 0.110, 0.120, 0.130, 0.140, 0.150, 0.160, 0.170, 0.180, 0.190, 0.200, 0.210, 0.220, 0.230, or 0.240 parts by mass, or may be within any range of the values ​​exemplified here.

[0125] In one embodiment of the present invention, a composition containing a chloroprene block copolymer and an aromatic compound having 7 to 10 carbon atoms, obtained after performing a concentration step, a dilution step, and / or an aromatic compound addition step as needed, is referred to as a chloroprene block copolymer latex composition.

[0126] 3. Composition for forming impregnated molded articles

[0127] An embodiment of the present invention provides a composition for forming an impregnated molded body containing the above-described chloroprene-based block copolymer latex composition. The composition for forming an impregnated molded body according to an embodiment of the present invention contains a chloroprene-based block copolymer and an aromatic compound having 7 to 10 carbon atoms. The total content of the aromatic compound having 7 to 10 carbon atoms is preferably 0.020 to 0.240 parts by weight relative to 100 parts by weight of the solid component of the chloroprene-based block copolymer contained in the composition for forming the impregnated molded body. The composition for forming an impregnated molded body according to an embodiment of the present invention may contain, for example, an anti-aging agent, and may contain other components depending on the purpose and application. Raw materials that may be contained in the composition for forming an impregnated molded body according to an embodiment of the present invention include, for example, vulcanizing agents, vulcanization accelerators, fillers or reinforcing agents, plasticizers, processing aids or lubricants, anti-aging agents, silane coupling agents, surfactants, etc.

[0128] Anti-aging agents

[0129] The composition for forming an impregnated molded article according to one embodiment of the present invention may contain an anti-aging agent. The composition for forming an impregnated molded article according to one embodiment of the present invention may contain 0.5 to 5.0 parts by weight of an anti-aging agent relative to 100 parts by weight of the solid component of the chloroprene-based block copolymer contained in the composition. The content of the anti-aging agent may be, for example, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, or 5.0 parts by weight, or may be within any range between the values ​​exemplified herein.

[0130] Anti-aging agents are used to improve heat resistance. They include primary anti-aging agents that scavenge free radicals and prevent auto-oxidation, and secondary anti-aging agents that neutralize hydroperoxides. Examples of primary anti-aging agents include phenolic anti-aging agents, amine-based anti-aging agents, acrylate-based anti-aging agents, imidazole-based anti-aging agents, metal carbamate salts, and waxes. Examples of secondary anti-aging agents include phosphorus-based anti-aging agents, sulfur-based anti-aging agents, and imidazole-based anti-aging agents. Examples of anti-aging agents are not specifically limited, but may include: N-phenyl-1-naphthylamine, alkylated diphenylamine, octylated diphenylamine, 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, p-(p-toluenesulfonamide)diphenylamine, N,N'-di-2-naphthyl-p-phenylenediamine, N,N'-diphenyl-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine, N-phenyl-N'-(3-methacryloyloxy-2-hydroxypropyl)-p-phenylenediamine, 1 1,3-Tris-(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 4,4'-Butylidene bis-(3-methyl-6-tert-butylphenol), 2,2-Thiobis(4-methyl-6-tert-butylphenol), 7-Octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenyl)propionate, Tetra-[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, Pentaerythritol-tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], Triethylene glycol-bis [3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine, tris-(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 2,2-thiodiethylidene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate tert-butyl-4-hydroxy)-hydrocinnamonamide, 2,4-bis[(octylthio)methyl]-o-cresol, 3,5-di-tert-butyl-4-hydroxybenzyl-phosphonate-diethyl ester, tetra[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamonate)]methane, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 3,9-bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxazolo[5.5] Undecane, tris(nonylphenyl) phosphite, tris(mixed monononyl and dinonylphenyl) phosphite, diphenyl-mono(2-ethylhexyl) phosphite, diphenyl-monotridecyl-phosphite, diphenyl-isodecyl-phosphite, diphenyl-isooctyl-phosphite, diphenyl-nonylphenyl-phosphite, triphenyl phosphite, tri(tridecyl) phosphite, triisodecyl phosphite, tris(2-ethylhexyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite, tetraphenyldipropylene glycol diphosphite, tetraphenyltetra(tridecyl)pentaerythritol tetraphosphite, 1,1,3-tris(2-methyl-4-di-tetrazylphosphite-5-tert-butylphenyl)butane, 4,4 '-Butylidene bis-(3-methyl-6-tert-butyl-di-tetrazyl phosphite), 2,2'-ethylidene bis(4,6-di-tert-butylphenol) fluorophosphite, 4,4'-isopropylidene-diphenol alkyl (C12-C15) phosphite, cyclic neopentanetetrayl bis(2,4-di-tert-butylphenyl phosphite), cyclic neopentanetetrayl bis(2,6-di-tert-butyl-4-phenyl phosphite), cyclic neopentanetetrayl bis(nonylphenyl phosphite), bis(nonylphenyl) pentaerythritol diphosphite, dibutyl phosphite hydrogen, distearate pentaerythritol diphosphite and hydrogenated bisphenol A pentaerythritol phosphite polymers, 2-mercaptobenzimidazole, and the butylation reaction products of p-cresol and dicyclopentadiene, etc.

[0131] <Vulcanizing Agents and Vulcanization Accelerators>

[0132] The composition for forming an impregnated molded article according to one embodiment of the present invention may also contain a vulcanizing agent and / or a vulcanization accelerator. Alternatively, the composition for forming an impregnated molded article according to one embodiment of the present invention may also be free of sulfur and the aforementioned thiuram-based, dithiocarbamate-based, thiourea-based, guanidine-based, xanthate-based, thiazole-based, etc., vulcanization accelerators. That is, the composition for forming an impregnated molded article includes: containing a vulcanizing agent but not a vulcanization accelerator, not containing a vulcanizing agent but containing a vulcanization accelerator, containing both a vulcanizing agent and a vulcanization accelerator, and not containing both a vulcanizing agent and a vulcanization accelerator. Whether to incorporate a vulcanizing agent and a vulcanization accelerator can be determined according to the desired impregnated molded article.

[0133] Examples of vulcanizing agents include, but are not limited to, sulfur. The amount of vulcanizing agent added can be 0 to 5.0 parts by weight relative to 100 parts by weight of the solids component of the chloroprene-based block copolymer contained in the composition for forming the impregnated molded body. The amount of vulcanizing agent added can 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 parts by weight, or can be within any range of the values ​​exemplified herein.

[0134] Vulcanization accelerators are reagents added during the vulcanization of raw rubber to increase the vulcanization speed, shorten the vulcanization time, lower the vulcanization temperature, reduce the amount of vulcanizing agent, and improve the physical properties of vulcanized rubber. They usually refer to reagents that promote sulfur vulcanization reactions.

[0135] Examples of vulcanization accelerators include thiuram-based, dithiocarbamate-based, thiourea-based, guanidine-based, xanthate-based, and thiazole-based accelerators, but these are not limited to. These can be used individually or in combination of two or more as needed.

[0136] Examples of thiuram-based accelerators include tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetra(2-ethylhexyl)thiuram disulfide, tetramethylthiuram monosulfide, and di(pentamethylene)thiuram tetrasulfide.

[0137] Examples of dithiocarbamate-based sulfidation accelerators include sodium dibutyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc N-ethyl-N-phenyldithiocarbamate, zinc N-pentamethylenedithiocarbamate, copper dimethyldithiocarbamate, iron(III) dimethyldithiocarbamate, and tellurium diethyldithiocarbamate, with zinc dibutyldithiocarbamate being particularly preferred.

[0138] Examples of thiourea-based thiourea accelerators include ethyl thiourea, N,N'-diethyl thiourea, trimethyl thiourea, and N,N'-diphenyl thiourea.

[0139] Examples of guanidine-based vulcanization accelerators include 1,3-diphenylguanidine, 1,3-di-o-tolylguanidine, 1-o-tolylbiguanidine, and di-o-tolylguanidine salts of di-o-catechol borate.

[0140] Examples of xanthate-based sulfurization accelerators include zinc butyl xanthate and zinc isopropyl xanthate.

[0141] Examples of thiazole-based sulfidation accelerators include 2-mercaptobenzothiazole, di-2-benzothiazole disulfide, zinc salt of 2-mercaptobenzothiazole, cyclohexylamine salt of 2-mercaptobenzothiazole, and 2-(4'-morpholinodithio)benzothiazole.

[0142] The amount of vulcanizing accelerator added can be 0 to 5.0 parts by weight relative to 100 parts by weight of the solid component of the chloroprene block copolymer contained in the composition for forming the dip-molded article. The amount of vulcanizing accelerator added can 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 can be within any range of the values ​​exemplified herein. The dip-molded article according to one embodiment of the present invention has sufficient mechanical strength even without vulcanization, and excellent elongation at break and hardness. Therefore, from the viewpoint of reducing allergies and lowering costs, it is possible to omit both vulcanizing agents and vulcanizing accelerators.

[0143] 4. Coating compositions

[0144] A coating composition according to one embodiment of the present invention contains the above-mentioned chloroprene-based block copolymer latex composition. The coating composition according to one embodiment of the present invention contains a chloroprene-based block copolymer and an aromatic compound having 7 to 10 carbon atoms. The total content of the aromatic compound having 7 to 10 carbon atoms is preferably 0.020 to 0.240 parts by mass relative to 100 parts by mass of the solid content of the chloroprene-based block copolymer latex composition in the coating composition. The coating composition according to one embodiment of the present invention may contain, for example, an anti-aging agent, and may contain other components depending on the purpose and application. Raw materials that may be contained in the coating composition according to one embodiment of the present invention include, for example, vulcanizing agents, vulcanization accelerators, fillers or reinforcing agents, plasticizers, processing aids or lubricants, anti-aging agents, silane coupling agents, surfactants, etc., and the types and amounts of each component are as described in the composition for dip-molding.

[0145] 5. Impregnation molding and coating (molded body)

[0146] An embodiment of the present invention may be an impregnation molded body of the above-described impregnation molded body forming composition.

[0147] The impregnated molded body can be suitably used for gloves, balloons, tubing, and boots. In one embodiment of the invention, the coating (molded body) can be a coating (molded body) of the aforementioned paint composition. The coating (molded body) can be suitably used for automotive intermediate coatings, etc.

[0148] (Tensile strength at break)

[0149] The impregnated molded article and coating (molded article) according to one embodiment of the present invention preferably have a tensile strength at break of 17.5 MPa or more, as measured according to JIS K 6251. Specifically, the tensile strength at break of the impregnated molded article is, for example, 17.5, 18.0, 19.0, 20.0, 21.0, 22.0, 23.0, 24.0, 25.0, 26.0, 27.0, 28.0, 29.0, or 30.0 MPa, or may be within any range between the values ​​exemplified herein.

[0150] (Elongation at break)

[0151] The impregnated molded article and coating (molded article) according to one embodiment of the present invention preferably have an elongation at break of 800% or more, as measured according to JIS K 6251. The elongation at break may be, for example, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, or 1700%, or may be within any range between the values ​​exemplified herein.

[0152] (Stress at 500% elongation)

[0153] The impregnated molded body and coating (molded body) of one embodiment of the present invention have stresses at 500% elongation measured according to JIS K 6251, for example, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0 MPa, or any two of the values ​​exemplified herein.

[0154] 6. Manufacturing method of impregnated molded body and coating (molded body)

[0155] A method for manufacturing an impregnated molded article according to one embodiment of the present invention may include an impregnation molding step of impregnating the above-mentioned impregnation molding composition to obtain an impregnated molded article, and a heat treatment step.

[0156] In addition, a method for manufacturing a coating film (molded body) according to one embodiment of the present invention may include a molding step of molding the above-mentioned coating composition by any method, and a heat treatment step.

[0157] As one embodiment of the present invention, the impregnation molding method includes, for example, the impregnation solidification method, the simple impregnation method, the thermosensitive impregnation method, and the electrodeposition method. From the viewpoint of ease of manufacture and ease of obtaining an impregnated molded body of a certain thickness, the impregnation solidification method can be used. Specifically, a ceramic molding mold coated with a calcium-based solidification solution is impregnated in an impregnation molding body forming composition, and the impregnation molding body forming composition is solidified. Then, water-soluble impurities are removed by leaching, and the mold is dried. Subsequently, an impregnation molding film (rubber coating) is formed by heating, and then the impregnation molding film is demolded. Thus, a film-like impregnated molded body can be obtained.

[0158] One embodiment of the molding method of the present invention may include, for example, the step of pouring the above-mentioned coating composition into any container such as a mold and drying it to obtain a coating film (molded body, such as a thin film).

[0159] A method for manufacturing an impregnated molded body and a coating (molded body) according to an embodiment of the present invention may include a heat treatment step of heat treating the aforementioned impregnated molded body and coating (molded body).

[0160] The heat treatment temperature can be 120–180°C, preferably 120–150°C. For example, the heat treatment temperature can be 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, or 220°C, or any value between two of the values ​​exemplified herein. The heat treatment time can be appropriately set according to the composition and shape of the chloroprene block copolymer, and can be 10–300 minutes. The heat treatment time can 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 any value between any two of the values ​​exemplified herein. As an example, an impregnated molded body according to one embodiment of the present invention can be a molded body obtained by heat treatment at 130°C for 30 minutes.

[0161] [Example]

[0162] The present invention will now be described in more detail based on embodiments, but the present invention is not limited to these embodiments.

[0163] (Example 1)

[0164] (Polymerization Step 1) Synthesis of Polymer Block (A-1)

[0165] Polymerization was carried out in a 10L autoclave equipped with a stirrer and a heating and cooling jacket. 3419g of pure water, 151g of potassium disproportionated rosinate (manufactured by Harima Chemicals Group, Inc.), 2.16g of potassium hydroxide, 17.1g of sodium salt of β-naphthalenesulfonic acid formalin condensate (manufactured by Kao Corporation, trade name: DEMOL N), 332g of styrene monomer, and 5.91g of butyl benzyl trithiocarbonate were added to raise the internal temperature to 80°C. The mixture was stirred at 200 rpm under a nitrogen atmosphere. 3.72g of 2,2'-azobis[2-(2-imidazolin-2-yl)propane]hydrogen dichloride (manufactured by Fujifilm and Kako Pure Chemicals, trade name: VA-044) was added as a polymerization initiator to begin polymerization. When the polymerization rate reached 95%, 0.30 g of 2,2'-azobis[2-(2-imidazolin-2-yl)propane]hydrogen dichloride (manufactured by Fujifilm and Koko Pure Chemical Industries, Ltd., trade name: VA-044) was added as a polymerization initiator. Polymerization continued until the polymerization rate reached 99%. To determine the physical properties, 20 ml of the resulting latex was sampled, and the remaining latex was used for polymerization step 2.

[0166] The sampled latex was mixed with a large amount of methanol to extract the resin components, and then filtered and dried to obtain a sample of polymer block (A-1). The number-average molecular weight, molecular weight distribution, and glass transition temperature of the polymer block (A-1) were determined by analyzing the obtained sample. The determination methods are described below.

[0167] (Polymerization Step 2) Synthesis of Chloroprene-based Polymer Block (B-1)

[0168] Following polymerization step 1, when the internal temperature dropped to 45°C, 3528 g of chloroprene monomer and 72 g of 1,9-nonanediol diacrylate were slowly added over 2 hours to continue polymerization. When the polymerization rate of chloroprene monomer reached 82%, a 10% by weight aqueous solution of N,N-diethylhydroxylamine as a polymerization terminator was added to terminate the polymerization, and unreacted chloroprene monomer was removed by vacuum distillation. Water was added to bring the solids concentration to 40% by weight, and the mixture was further concentrated to 50% by weight, with 0.1 g of styrene added. To determine the physical properties, 20 ml of the resulting latex was sampled, and the remaining latex was used to prepare a composition for dip-molding and to fabricate dip-molded bodies.

[0169] The latex samples were used for content analysis of aromatic compounds with carbon numbers 7-10 and mechanical stability evaluation. Additionally, a chloroprene block copolymer sample was obtained by mixing the aromatic compounds with carbon numbers 7-10 with a large amount of methanol to extract the resin components, followed by filtration and drying. The contents (mass %) of the polymer blocks (A-1) and (B-1) of the chloroprene block copolymer were determined by analyzing the obtained samples. The analytical results are shown in Table 1. Furthermore, the determination methods are described below.

[0170] (Examples 2-6, Comparative Examples 1-3)

[0171] In polymerization steps 1 and 2, the types and amounts of each reagent, as well as the polymerization conditions, are set as described in the table. Otherwise, chloroprene block copolymer latex is obtained in the same manner as in Example 1.

[0172] [Analysis of polymer block (A)]

[0173] <Determination of the number-average molecular weight and molecular weight distribution of polymer block (A)>

[0174] The number-average molecular weight and molecular weight distribution are polystyrene conversion values ​​obtained by gel permeation chromatography (GPC) under the following test conditions.

[0175] Device Name: HLC-8320 (Manufactured by Tosoh Corporation)

[0176] Column: 3 TSKgel GMHHR-H columns in series

[0177] Temperature: 40℃

[0178] Detection: Differential Refractive Index

[0179] Solvent: Tetrahydrofuran

[0180] Calibration curve: prepared using standard polystyrene (PS).

[0181] <Glass transition temperature of polymer block (A)>

[0182] The glass transition temperature was determined using a differential scanning calorimeter according to JIS K 7121 and the following method.

[0183] Device Name: DSC1 (Manufactured by Mettler Toledo)

[0184] Procedure: Under a nitrogen flow of 50 ml / min, the temperature is increased to 120°C at a rate of 10°C / min, held at 120°C for 10 minutes, cooled to -60°C, and then increased to 120°C at a rate of 10°C / min to obtain the DSC curve. The temperature at the intersection of the straight line extending from the high-temperature side baseline to the low-temperature side in the obtained DSC curve and the tangent line drawn at the maximum slope on the high-temperature side curve at the peak is defined as the glass transition temperature.

[0185] [Analysis of Chloroprene-based Block Copolymer Latex Compositions]

[0186] <Determination of the content of polymer blocks (A) and chloroprene-based polymer blocks (B) in chloroprene-based block copolymers>

[0187] Using pyrolysis gas chromatography and 1 H-NMR was determined using the following method.

[0188] Pyrolysis Gas Chromatograph Instrument Name: HP5890-II

[0189] Column: DB-5 0.25mmφ×30m (film thickness 1.0μm)

[0190] Column temperature: 50℃ (5min) → 10℃ / min → 150℃ → 25℃ / min → 300℃

[0191] Inlet temperature: 250℃

[0192] Detector temperature: 280℃

[0193] Detector: FID

[0194] 1 H-NMR device name: JNM-ECX-400 (manufactured by Nippon Electronics Co., Ltd.)

[0195] Procedure: A pyrolysis gas chromatograph was used to determine the chloroprene block copolymer, which consists of a polymer block (A) and a chloroprene-based polymer block (B) without unsaturated nitrile monomer units. The area ratio of the peaks from polymer block (A) to the peaks from chloroprene-based polymer block (B) was used, along with other parameters. 1 A calibration curve was constructed by determining the content of polymer block (A) and chloroprene polymer block (B) in the obtained chloroprene block copolymer using ¹H-NMR. The chloroprene block copolymer sample precipitated by mixing latex with methanol was determined using pyrolysis gas chromatography. The area ratio of the peak from polymer block (A) to the peak from chloroprene polymer block (B) was used, and the content of polymer block (A) and chloroprene polymer block (B) in the chloroprene block copolymer was determined using the aforementioned calibration curve.

[0196] <Concentration and content of aromatic compounds with carbon numbers 7-10>

[0197] Aromatic compounds with carbon numbers 7–10 in chloroprene block copolymer latex compositions were analyzed using gas chromatography (headspace method). 0.03 g of the chloroprene block copolymer latex composition was collected in a sample vial and sealed, and the determination was performed under the following conditions.

[0198] (Gas Chromatography Conditions)

[0199] Device Name: Agilent GC-8890

[0200] Chromatographic column: DB-1 φ0.25mm×60m (film thickness 1μm)

[0201] Column temperature: 50℃ → 5℃ / min → 300℃

[0202] Inlet temperature: 270℃

[0203] Detector temperature: 300℃

[0204] Detector: FID

[0205] Using a calibration curve obtained from the peak area of ​​aromatic compounds with carbon numbers 7-10 versus the content of aromatic compounds with carbon numbers 7-10, the concentration [ppm] of aromatic compounds with carbon numbers 7-10 in the chloroprene block copolymer latex composition was determined. The results are shown in Table 1. From the determined concentration of aromatic compounds with carbon numbers 7-10 in the chloroprene block copolymer latex composition, the amount [parts by mass] of aromatic compounds with carbon numbers 7-10 relative to 100 parts by mass of the solid component in the chloroprene block copolymer latex composition was calculated using the following formula. The results are shown in Table 1.

[0206] The amount of aromatic compounds with 7 to 10 carbon atoms in 100 parts by mass of the solid component in the chloroprene block copolymer latex composition [parts by mass] = 100 × (concentration of aromatic compounds with 7 to 10 carbon atoms [ppm] / 1,000,000 × 100 / (concentration of solid component in the chloroprene block copolymer latex composition [mass %])

[0207] Furthermore, in Examples 1-3, 5, 6, and Comparative Examples 1-3, styrene was detected at concentrations shown in Table 1 as aromatic compounds with 7 to 10 carbon atoms. Additionally, in Example 4, styrene and divinylbenzene were detected at concentrations shown in Table 1.

[0208] <Mechanical Stability>

[0209] Using a Maron test apparatus, a shear force of 10 kg and 1000 rpm was applied to 50 g of a chloroprene block copolymer latex composition with a solids content of 50% by mass for 10 minutes, and the amount of agglomerates generated was evaluated. After applying the shear force under the above conditions, the agglomerates adhering to the rotor of the Maron test apparatus were collected on an SUS80 mesh wire mesh, washed with pure water, and dried under reduced pressure, and their mass was measured. The agglomerate generation rate was calculated from the measured dried mass of the agglomerates according to the following formula, and evaluated according to the following evaluation criteria.

[0210] Agglomerate formation rate (mechanical stability) (mass %) = Dry mass of aggregate [g] / Mass of solids component of chloroprene block copolymer latex composition [g] × 100

[0211] ◎: The agglomerate formation rate is 0.01% by mass or more and 1.00% by mass or less.

[0212] 〇: The agglomerate formation rate is greater than 1.00% by mass and less than 2.00% by mass.

[0213] ×: Aggregate formation rate exceeds 2.00% by mass.

[0214] [Evaluation of compositions for dip-molded articles]

[0215] <Preparation of Compositions for Dip-Molded Articles>

[0216] To prepare a composition for impregnation molding, 2 parts by mass of a compound obtained by butylating a condensate of p-cresol and dicyclopentadiene (Nocrac PBK, manufactured by Ouchi Shinsei Chemical Co., Ltd.) as an anti-aging agent, 0.1 parts by mass of a sodium salt of a β-naphthalenesulfonic acid formalin condensate (DEMOL N, manufactured by Kao Corporation) as a dispersant, and water were added to achieve a solid content concentration of 30% by mass. The mixture was then mixed at 20°C for 16 hours using a ceramic ball mill to prepare the composition.

[0217] <Mechanical Stability>

[0218] Using a Maran's test apparatus, a shear force of 10 kg and 1000 rpm was applied to 50 g of a 30% solids concentration impregnation molding composition for 10 minutes, and the amount of agglomerates generated was evaluated. After applying the shear force under the above conditions, the agglomerates adhering to the rotor of the Maran's test apparatus were collected onto an SUS80 mesh wire mesh, washed with pure water, and dried under reduced pressure. The mass was then measured. The agglomerate formation rate was calculated from the measured dried mass of the agglomerates using the following formula, and this rate was used as an indicator of mechanical stability. The smaller the agglomerate formation rate, the more stable the agglomerates are relative to the shear force, and the better the mechanical stability.

[0219] Agglomerate formation rate (mechanical stability) (mass %) = Dry mass of aggregate [g] / Mass of solids component of chloroprene block copolymer latex composition [g] × 100

[0220] ◎: The agglomerate formation rate is 0.01% by mass or more and 1.00% by mass or less.

[0221] 〇: The agglomerate formation rate is greater than 1.00% by mass and less than 2.00% by mass.

[0222] ×: Aggregate formation rate exceeds 2.00% by mass.

[0223] [Evaluation of the molded part]

[0224] (Thin film fabrication)

[0225] A ceramic cylinder with an outer diameter of 50 mm was immersed in a coagulation solution containing 62 parts by mass of water, 35 parts by mass of potassium nitrate tetrahydrate, and 3 parts by mass of calcium carbonate for 1 second, and then removed. After drying for 4 minutes, it was immersed in the above-prepared impregnation molding composition for 2 minutes. Then it was washed with running water at 45°C for 1 minute and heat-treated at 130°C for 30 minutes to remove moisture, thereby producing a test impregnation molding body (140×150 mm, thickness: 0.2 mm).

[0226] (Stress at 500% elongation, tensile strength at break, elongation at break)

[0227] Using test dip-molded bodies, stress at 500% elongation, tensile strength at break, and elongation at break were determined according to JIS K 6251:2017.

[0228] [Table 1-1]

[0229]

[0230] [Table 1-2]

[0231]

Claims

1. A chloroprene-based block copolymer latex composition comprising a chloroprene-based block copolymer containing polymer blocks (A) and chloroprene-based polymer blocks (B), The polymer block (A) contains monomer units derived from monomer (A). The monomer (A) is a monomer that, when homopolymerized, yields a polymer with a glass transition temperature above 80°C. In the chloroprene-based block copolymer latex composition, the total content of aromatic compounds with 7 to 10 carbon atoms is 0.020 to 0.240 parts by mass relative to 100 parts by mass of the solid components in the chloroprene-based block copolymer latex composition.

2. The chloroprene-based block copolymer latex composition according to claim 1, wherein, The aromatic compounds having 7 to 10 carbon atoms include at least one selected from the group consisting of toluene, ethylbenzene, cumene, xylene, diethylbenzene, propyltoluene, styrene, and divinylbenzene.

3. The chloroprene-based block copolymer latex composition according to claim 1 or 2, wherein, The content of the polymer block (A) is 7.0 to 15.0% by mass relative to 100% by mass of the chloroprene block copolymer.

4. The chloroprene-based block copolymer latex composition according to claim 1 or 2, wherein, The number-average molecular weight of the polymer block (A) is 14,000 to 30,000.

5. The chloroprene-based block copolymer latex composition according to claim 1 or 2, wherein, The polymer block (A) contains monomer units from the aromatic compounds having 7 to 10 carbon atoms.

6. A composition for forming an impregnated molded article, comprising the chloroprene-based block copolymer latex composition of claim 1 or 2.

7. An impregnation molded article, which is an impregnation molded article of the impregnation molded article forming composition according to claim 6.

8. A coating composition comprising the chloroprene-based block copolymer latex composition of claim 1 or 2.

Images