Chloroprene polymer latex composition and adhesive composition

Abstract

Provided are: a chloroprene polymer latex composition with which it is possible to obtain an adhesive composition having excellent initial adhesion strength and freezing stability; and an adhesive composition containing the chloroprene polymer latex composition. According to the present invention, provided is a chloroprene polymer latex composition containing a chloroprene polymer and a nonionic emulsifier, the chloroprene polymer latex composition containing 0.005-0.40 parts by mass of the nonionic emulsifier per 100 parts by mass of the chloroprene polymer, and the amount of the nonionic emulsifier per 100 parts by mass of the chloroprene polymer. The chloroprene polymer has an average particle diameter of 80-160 nm and a toluene insoluble content of 30% by mass or less.

Description

Technical Field

[0001] The present invention relates to a chloroprene polymer latex composition and an adhesive composition. Background Art

[0002] Adhesives containing chloroprene polymers can obtain high adhesive strength for various adherends at low pressure, and are thus used in solvent-based contact adhesives, graft adhesives, etc. However, since solvent-based adhesives are flammable and toxic, their regulation has become stricter year by year. Therefore, aqueous adhesives using chloroprene polymer latexes are being developed.

[0003] For example, Patent Document 1 discloses a chloroprene polymer latex and an adhesive composition containing the chloroprene polymer latex. The chloroprene polymer latex is characterized by containing an alkali metal salt of a carboxylic acid (emulsifier) and 0.1 to 0.5 parts by weight (per 100 parts by weight of the chloroprene polymer latex) of a polyoxyalkylene derivative represented by a specific formula.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] However, adhesives containing existing chloroprene polymer latex compositions, especially aqueous adhesives, are difficult to balance both initial adhesive strength and freeze-thaw stability. The present invention has been made in view of the above circumstances, and aims to provide a chloroprene polymer latex composition capable of obtaining an adhesive composition having excellent initial adhesive strength and freeze-thaw stability, and an adhesive composition containing the chloroprene polymer latex composition. Solutions to the Problems

[0006] According to the present invention, there is provided a chloroprene polymer latex composition containing a chloroprene polymer and a nonionic emulsifier, wherein the chloroprene polymer latex composition contains 0.005 to 0.40 parts by mass of the nonionic emulsifier relative to 100 parts by mass of the chloroprene polymer, the average particle size of the chloroprene polymer is 80 to 160 nm, and the toluene-insoluble component is 30% by mass or less.

[0007] After intensive research, the inventors of the present invention found that in a chloroprene polymer latex composition containing a chloroprene polymer and a nonionic emulsifier, by setting the amount of the nonionic emulsifier, the average particle size of the chloroprene polymer, and the toluene-insoluble component within specific numerical ranges, a chloroprene polymer latex composition having excellent initial adhesive strength and freeze-thaw stability can be obtained, thus completing the present invention.

[0008] The following illustrate various embodiments of the present invention. The embodiments shown below can be combined with each other. [1] A chloroprene polymer latex composition comprising a chloroprene polymer and a nonionic emulsifier, wherein the chloroprene polymer latex composition contains 0.005 to 0.40 parts by mass of the nonionic emulsifier relative to 100 parts by mass of the chloroprene polymer, the average particle size of the chloroprene polymer is 80 to 160 nm, and the toluene-insoluble component is 30% by mass or less. [2] The chloroprene polymer latex composition according to [1], wherein the nonionic emulsifier includes at least one selected from the group consisting of polyoxyalkylene phenyl ether-based emulsifiers, polyoxyalkylene alkyl ether-based emulsifiers, polyoxyethylene sorbitan fatty acid ester-based emulsifiers, polyoxyethylene sorbitol fatty acid ester-based emulsifiers, sorbitan fatty acid ester-based emulsifiers, glycerol fatty acid ester-based emulsifiers, polyoxyethylene alkylamine-based emulsifiers, polyoxyethylene fatty acid ester-based emulsifiers, and alkyl alkanolamide-based emulsifiers. [3] An adhesive composition containing the chloroprene polymer latex composition according to [1] or [2]. [4] The adhesive composition according to [3], which contains a pH adjuster. [5] The adhesive composition according to [3] or [4], which is an adhesive composition for polyurethane foam. Effects of the Invention

[0009] The chloroprene-based polymer latex composition according to the present invention can provide an adhesive composition having excellent initial adhesion strength and freeze-thaw stability. The adhesive composition containing the chloroprene-based polymer latex composition according to the present invention has excellent initial adhesion strength. When using the adhesive, even if the drying time of the adhesive layer is shortened or eliminated, excellent initial adhesion strength can be exhibited. In addition, excellent initial adhesion strength can be exhibited even in a moist state where the drying temperature is set to room temperature. That is, in the bonding process of the adhesive composition containing the chloroprene-based polymer latex composition according to the present invention, since long-term drying or heat drying required in the past is no longer needed, the operation process can be shortened, energy and costs can be reduced, and the equipment can be simplified. In addition, the chloroprene-based polymer latex composition according to the present invention and the adhesive composition containing the chloroprene-based polymer latex composition have excellent freeze-thaw stability and are not likely to solidify even in a severe low-temperature environment and / or after being stored in a low-temperature environment. The adhesive composition containing the chloroprene-based polymer latex composition of the present invention can be suitably used as, for example, a spray-type adhesive used in the adhesion of polyolefin resins, foams, particularly polyurethane foams. Detailed Description of the Invention

[0010] The embodiments of the present invention are illustrated below to explain the present invention in detail. The present invention is not limited by any of these descriptions. The respective characteristic matters of the embodiments of the present invention shown below can be combined with each other. In addition, each characteristic matter can independently constitute an invention.

[0011] 1. Chloroprene-based polymer latex composition The chloroprene-based polymer latex composition according to the present invention contains a chloroprene-based polymer and a nonionic emulsifier. The chloroprene-based polymer latex composition according to the present invention contains 0.005 to 0.40 parts by mass of a nonionic emulsifier relative to 100 parts by mass of the chloroprene-based polymer. In addition, the average particle diameter of the chloroprene-based polymer is 80 to 160 nm, and the toluene-insoluble component is 30% by mass or less.

[0012] 1.1 Chloroprene-based polymer and chloroprene-based polymer latex In the present invention, a chloroprene polymer latex means a latex containing a chloroprene polymer. Further, a chloroprene polymer means a polymer containing monomer units derived from 2-chloro-1,3-butadiene (hereinafter also referred to as chloroprene monomer), including a homopolymer of chloroprene monomer and a copolymer containing monomer units derived from chloroprene monomer and other monomers copolymerizable with chloroprene monomer. Examples of other monomers include 1-chloro-1,3-butadiene, 2,3-dichloro-1,3-butadiene, butadiene, isoprene, styrene, acrylonitrile, acrylic acid and its esters, methacrylic acid and its esters, and the like.

[0013] In the chloroprene polymer latex composition according to one embodiment of the present invention, when the chloroprene polymer contained in the chloroprene polymer latex composition is set to 100% by mass, it preferably contains 60 to 100% by mass of chloroprene monomer units. The content rate of chloroprene monomer units is, for example, 60, 65, 70, 75, 80, 85, 90, 95, 99, 100% by mass, and may also be within the range between any two values exemplified herein.

[0014] The chloroprene polymer latex composition according to one embodiment of the present invention may contain one kind of chloroprene polymer or two or more kinds of chloroprene polymers. The chloroprene polymer latex composition according to one embodiment of the present invention preferably contains a homopolymer of chloroprene monomer. In the chloroprene polymer latex composition according to one embodiment of the present invention, relative to 100% by mass of the solid content of the chloroprene polymer latex contained in the chloroprene polymer latex composition, it preferably contains 60 to 100% by mass of the homopolymer of chloroprene monomer in terms of solid content. The content rate of the homopolymer of chloroprene monomer is, for example, 60, 65, 70, 75, 80, 85, 90, 95, 100% by mass, and may also be within the range between any two values exemplified herein. By containing a chloroprene polymer, the contact property, heat-resistant adhesiveness, and initial adhesiveness of the adhesive composition containing the chloroprene polymer latex composition can be improved in the chloroprene polymer latex composition according to one embodiment of the present invention.

[0015] <Toluene-insoluble component> The chloroprene-based polymer according to the present invention has a toluene-insoluble component of 30% by mass or less. In the present invention, the toluene-insoluble component refers to the content rate of the gel component that is insoluble in the toluene solvent in the chloroprene-based polymer. In addition, the sol refers to the component that is soluble in the toluene solvent. The chloroprene-based polymer according to the present invention has a toluene-insoluble component (gel component) of 30% by mass or less and contains a lot of sol having excellent molecular mobility. Therefore, it is speculated that the molecular chains of the chloroprene-based polymer at the bonding interface quickly fuse, thereby instantaneously exhibiting the bonding strength and being able to exhibit a more excellent initial bonding strength.

[0016] The toluene-insoluble component 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, 30% by mass, and may also be within the range between any two values exemplified herein.

[0017] When the mass of the chloroprene-based polymer obtained by freeze-drying the chloroprene-based polymer latex is denoted as Ag and the gel component (insoluble component) separated from the latex after freeze-drying from the mixture dissolved in toluene is denoted as Bg, the toluene-insoluble component can be obtained by the following formula, specifically, it can be obtained by the method described in the examples. Toluene-insoluble component (gel component) = B / A × 100 (%)

[0018] The toluene-insoluble component can be controlled by adjusting the polymerization conditions during the production of the chloroprene-based polymer latex, such as adjusting the types and amounts of the polymerization initiator and the chain transfer agent, the polymerization temperature, the polymerization time, the polymerization rate, and other production conditions.

[0019] In addition, when the chloroprene-based polymer latex composition contains two or more kinds of chloroprene-based polymers, the toluene-insoluble component of the mixture of two or more kinds of chloroprene-based polymers is preferably within the above numerical range.

[0020] <Average particle size> The average particle size of the chloroprene-based polymer latex according to an embodiment of the present invention is 80 to 160 nm. The average particle size is, for example, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160 nm, and may also be within the range between any two values exemplified herein.

[0021] The average particle diameter of the chloroprene polymer latex can be a value obtained by the cumulant method using the autocorrelation function determined by the photon correlation method in the dynamic light scattering method. Specifically, it can be obtained by the method described in the examples. By adjusting the polymerization conditions during the production of the chloroprene polymer latex, such as by adjusting the type and amount of emulsifier, polymerization temperature, polymerization time, polymerization rate, etc., the average particle diameter of the chloroprene polymer latex can be controlled. As an example, the average particle diameter of the chloroprene polymer latex can be controlled by adjusting the polymerization time according to the type of emulsifier (for example, the amount of conjugated resin acid in the emulsifier).

[0022] 1.2 Non-ionic emulsifier The chloroprene polymer latex composition according to the present invention contains 0.005 to 0.40 parts by mass of a non-ionic emulsifier relative to 100 parts by mass of the chloroprene polymer. The content of the non-ionic emulsifier is, for example, 0.005, 0.007, 0.009, 0.01, 0.02, 0.03, 0.05, 0.07, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40 parts by mass, and can also be within the range between any two values exemplified here. The chloroprene polymer latex composition according to the present invention can be made into a chloroprene polymer latex composition that can obtain an adhesive composition having excellent initial adhesion strength and freeze-thaw stability by containing a chloroprene polymer having a specific toluene-insoluble component content and average particle diameter, and by limiting the content of the non-ionic emulsifier. The content of the non-ionic emulsifier relative to 100 parts by mass of the chloroprene polymer can be obtained by the method described in the examples.

[0023] The non-ionic emulsifier preferably includes at least one selected from the group consisting of polyoxyalkylene phenyl ether emulsifiers, polyoxyalkylene alkyl ether emulsifiers, polyoxyethylene sorbitan fatty acid ester emulsifiers, polyoxyethylene sorbitol fatty acid ester emulsifiers, sorbitan fatty acid ester emulsifiers, glycerol fatty acid ester emulsifiers, polyoxyethylene alkylamine emulsifiers, polyoxyethylene fatty acid ester emulsifiers, and alkyl alkanolamide emulsifiers. As the non-ionic emulsifier, it preferably includes at least one of polyoxyalkylene phenyl ether emulsifiers and polyoxyalkylene alkyl ether emulsifiers, more preferably includes at least one of polyoxyethylene phenyl ether emulsifiers and polyoxyethylene alkyl ether emulsifiers, and further preferably contains polyoxyethylene styrenyl phenyl ether emulsifiers. In addition, the non-ionic emulsifier may not contain rosin acid (and its alkali metal salts) described later.

[0024] The polyoxyalkylene alkyl ether emulsifier and the polyoxyalkylene phenyl ether emulsifier can be represented as RO(EO) n (PO) mIn the formula, R is a straight-chain or branched alkyl group having 8 to 30 carbon atoms, or an unsubstituted or substituted phenyl group, preferably a straight-chain or branched alkyl group having 8 to 12 carbon atoms, or an unsubstituted or substituted phenyl group, more preferably a styrenated phenyl group in which a hydrogen atom of the phenyl group is substituted with a styryl C6H5-CH(CH3)- group. In addition, EO represents an ethylene oxide group, PO represents a propylene oxide group, an epoxy alkyl group having 3 or more carbon atoms such as an epoxy butyl group, and their arrangement can be block-shaped or random-shaped. In addition, n and m are each 0 to 100, preferably 0 to 50. In addition, n + m > 0.

[0025] 1.3 Rosin acid and its alkali metal salts The chloroprene polymer latex composition according to the present invention may contain an emulsifier other than a nonionic emulsifier. As an emulsifier other than a nonionic emulsifier, an anionic emulsifier and a cationic emulsifier can be cited. As an anionic emulsifier, rosin acid and its alkali metal salts can be cited. The chloroprene polymer latex composition according to the present invention may contain 3.0 to 7.0 parts by mass of rosin acid and its alkali metal salts with respect to 100 parts by mass of the chloroprene polymer. The content of rosin acid and its alkali metal salts is, for example, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0 parts by mass, and may also be within the range between any two values exemplified here.

[0026] The chloroprene polymer latex composition according to one embodiment of the present invention may contain rosin acid and its alkali metal salts, and the rosin acid and its alkali metal salts may contain a conjugated resin acid.

[0027] Conjugated resin acid means a resin acid having a conjugated double bond in a resin acid (rosin acid). As conjugated resin acids, abietic acid, neoabietic acid, palustric acid, and levopimaric acid can be cited. The conjugated resin acid preferably contains at least one of abietic acid and palustric acid, and more preferably contains abietic acid. In addition, as non-conjugated resin acids, dehydroabietic acid, pimaric acid, isopimaric acid, dihydroabietic acid, dihydropimaric acid, ring-opening dehydroabietic acid, deisopropyl dehydroabietic acid, and demethyl dehydroabietic acid can be cited.

[0028] It is known that in the emulsion polymerization of a chloroprene polymer, rosin acid and its alkali metal salts are used as emulsifiers. However, when using rosin acid and its alkali metal salts containing a conjugated resin acid having a conjugated double bond, polymerization may be inhibited. In addition, the stability of the obtained chloroprene polymer latex may be insufficient, or the adhesion characteristics may be insufficient. From the above viewpoints, in the emulsion polymerization of a chloroprene polymer (especially in the emulsion polymerization of a chloroprene polymer used as an adhesive), disproportionated rosin acid and its alkali metal salts, especially disproportionated rosin acid alkali metal salts, are mostly used as emulsifiers.

[0029] In the chloroprene polymer latex composition according to the present invention, 0 to 3.5 parts by mass of a conjugated resin acid may be contained relative to 100 parts by mass of the chloroprene polymer. The content of the conjugated resin acid relative to 100 parts by mass of the chloroprene polymer is, for example, 0, 0.1, 0.2, 0.3, 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, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5 parts by mass, and may also be within the range between any two values exemplified herein. The chloroprene polymer latex composition according to the present invention may not contain a conjugated resin acid.

[0030] In the chloroprene polymer latex composition according to one embodiment of the present invention, 0.5 to 6.0 parts by mass of a non-conjugated resin acid may be contained relative to 100 parts by mass of the chloroprene polymer. The content of the non-conjugated resin acid relative to 100 parts by mass of the chloroprene polymer is, for example, 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, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 parts by mass, and may also be within the range between any two values exemplified herein.

[0031] In the chloroprene polymer latex composition according to one embodiment of the present invention, when the total content of the conjugated resin acid and the non-conjugated resin acid in the chloroprene polymer latex composition is set to 100% by mass, the content ratio of the conjugated resin acid is, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 90, 100% by mass, and may also be within the range between any two values exemplified herein.

[0032] Among the conjugated resin acids contained in the chloroprene-based polymer latex composition, there are also conjugated resin acids present in the form of conjugated resin acid salts. In the polymerization of chloroprene-based polymers, rosin acids (including conjugated resin acids and non-conjugated resin acids), conjugated resin acids, and non-conjugated resin acids can also be added in the form of rosin acid salts, conjugated resin acid salts, and non-conjugated resin acid salts. In addition, the emulsion polymerization method using rosin acid, etc. is mostly carried out under strongly alkaline conditions. In strongly alkaline chloroprene-based polymer latexes, rosin acid, conjugated resin acid, and non-conjugated resin acid mostly exist in the form of salts. Examples of the salts include alkali metal salts, such as potassium salts and sodium salts. Examples of the compounds that form salts with rosin acid, conjugated resin acid, and non-conjugated resin acid include potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate. Conjugated resin acids include potassium abietate, potassium neoabietate, potassium palustricate, potassium levopimarate, sodium abietate, sodium neoabietate, sodium palustricate, and sodium levopimarate.

[0033] The content of conjugated resin acid can be calculated by the following method: Using the solid component obtained by freeze-drying rosin acid, its alkali metal salt, or chloroprene-based polymer latex, the extract obtained by extracting with the ethanol / toluene azeotropic mixture (ETA solution) specified in JIS K 6229 and subjecting it to hydrochloric acid treatment is subjected to gas chromatography analysis. From the measurement results of gas chromatography, the peak areas of the conjugated resin acid component and the non-conjugated resin acid component are obtained, and the contents of the conjugated resin acid component and the non-conjugated resin acid component relative to the total peak area are calculated. Specifically, it can be calculated according to the method described in the examples.

[0034] The chloroprene-based polymer latex composition according to an embodiment of the present invention may include rosin acid containing conjugated resin acid and its alkali metal salts, and the content rate of conjugated resin acid in rosin acid and its alkali metal salts is, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 90, 100% by mass, and may also be within the range between any two values exemplified here. The chloroprene-based polymer latex composition according to an embodiment of the present invention may also not include rosin acid containing conjugated resin acid and its alkali metal salts.

[0035] In addition, the chloroprene-based polymer latex composition according to an embodiment of the present invention may also contain emulsifiers and dispersants other than rosin acid, its alkali metal salts, and nonionic emulsifiers. Regarding other emulsifiers and dispersants, they will be described in the subsequent description of the manufacturing method of chloroprene-based polymer latexes.

[0036] 1.4 Manufacturing method of chloroprene-based polymer latex The method for manufacturing a chloroprene-based polymer latex according to the present invention is not particularly limited and can be carried out by the following method. According to an embodiment of the method for manufacturing a chloroprene-based polymer latex of the present invention, it may include an emulsion polymerization step. In the emulsion polymerization step, a chloroprene monomer, or a raw material monomer containing a chloroprene monomer and other monomers copolymerizable therewith, is emulsion polymerized by appropriately using an emulsifier, a dispersant, a polymerization initiator, a chain transfer agent, a reducing agent, etc. When the target polymerization rate is reached, a polymerization terminator is added, thereby obtaining a chloroprene-based polymer latex. In addition, additives such as a nonionic emulsifier can be added to the chloroprene-based polymer latex obtained in this way as needed. In addition, unreacted monomers can be removed by a concentration method such as vacuum distillation.

[0037] (Emulsifier) The emulsifier preferably contains rosin acid and its alkali metal salts. As described above, generally, the disproportionated rosin acid used for the emulsion polymerization of chloroprene-based polymers is obtained by subjecting raw rosin acid to disproportionation treatment, and the content of conjugated resin acid in the disproportionated rosin acid is extremely small or does not contain conjugated resin acid. In one embodiment of the present invention, raw rosin acids such as tall oil rosin, gum rosin, and wood rosin that have not been subjected to disproportionation treatment, and rosin acids that have not been completely modified to non-conjugated resin acids (including cases where a part is modified to non-conjugated resin acids and a part remains as conjugated resin acids) can be used as emulsifiers.

[0038] The addition amount of rosin acid and its alkali metal salts is preferably such that the contents of rosin acid, conjugated resin acid, and non-conjugated resin acid in the chloroprene-based polymer latex composition fall within the above numerical ranges. Based on 100 parts by mass of all monomers used, the addition amount of rosin acid and its alkali metal salts can be 3.0 to 7.0 parts by mass. The addition amount of rosin acid and its alkali metal salts is, for example, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0 parts by mass, and can also be within the range between any two of the values exemplified herein.

[0039] The emulsifier may include rosin acid containing conjugated resin acid and its alkali metal salts, and the content rate of conjugated resin acid in rosin acid and its alkali metal salts is, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 90, 100% by mass, and can also be within the range between any two of the values exemplified herein. According to an embodiment of the present invention, rosin acid and its alkali metal salts may not include rosin acid containing conjugated resin acid and its alkali metal salts.

[0040] As an emulsifier used in the emulsion polymerization process, it may include rosin acid containing disproportionated rosin acid and / or its alkali metal salt. When emulsifying a raw material containing rosin acid and / or its salt, and disproportionated rosin acid and / or its salt, the emulsifier may contain, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100 parts by mass of the raw material rosin acid and / or its salt relative to a total of 100 parts by mass of rosin acid and / or its alkali metal salt, and may also be within the range between any two values exemplified herein.

[0041] The emulsifier may also include an emulsifier and a dispersant other than rosin acid and / or its alkali metal salt. As the emulsifier and the dispersant other than rosin acid and / or its alkali metal salt, cationic, anionic, and nonionic emulsifiers and dispersants can be used. In one embodiment of the present invention, the emulsion used in the emulsion polymerization process may contain rosin acid and / or its alkali metal salt, and an anionic emulsifier and dispersant. From the viewpoint of stabilizing the chloroprene polymer latex when adding a pH regulator, it is preferable to use a sulfate-based and a sulfonate-based anionic emulsifier and dispersant in combination. Specific examples include alkyl sulfonates having 8 to 20 carbon atoms, alkyl aryl sulfates, condensates of sodium naphthalene sulfonate and formaldehyde, and sodium alkyl diphenyl ether disulfonate. The addition amount of the anionic emulsifier and dispersant may be 0.05 to 5 parts by mass relative to 100 parts by mass of all the monomers used. The addition amount of the anionic emulsifier and dispersant is, for example, 0.05, 0.1, 0.2, 0.3, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0 parts by mass relative to 100 parts by mass of all the monomers used, and may also be within the range between any two values exemplified herein.

[0042] (Chain transfer agent) In the emulsion polymerization process, in order to adjust the molecular weight and molecular weight distribution of the chloroprene-based polymer and the toluene-insoluble component, it is preferable to add a chain transfer agent. The chain transfer agent can be added at the initial stage of polymerization or during the polymerization process. As the chain transfer agent, long-chain alkyl mercaptans such as n-dodecyl mercaptan and tert-dodecyl mercaptan, and dialkyl xanthogen disulfides such as diisopropyl xanthogen disulfide and diethyl xanthogen disulfide are preferred. Since the molecular weight and the toluene-insoluble component are easily controlled, long-chain alkyl mercaptans are preferred. As the chain transfer agent, one kind can be used alone or two or more kinds can be used in combination. The total addition amount of the chain transfer agent added during emulsion polymerization is preferably 0.005 to 0.12 parts by mass relative to 100 parts by mass of the chloroprene monomer and the monomer copolymerizable with the chloroprene monomer. The total addition amount of the chain transfer agent is, for example, 0.005, 0.01, 0.05, 0.10, 0.11, 0.12 parts by mass, and can also be within the range between any two values exemplified here.

[0043] (Initiator) As the initiator for polymerization, ordinary radical polymerization initiators can be used. Specifically, organic or inorganic peroxides such as benzoyl peroxide, potassium persulfate, and ammonium persulfate, and azo compounds such as azobisisobutyronitrile can be used. In addition, cocatalysts such as anthraquinone sulfonate, potassium sulfite, and sodium sulfite can be appropriately used in combination.

[0044] (Potassium hydroxide and sodium hydroxide) In the emulsion polymerization process, sodium hydroxide and / or potassium hydroxide can be used. Relative to 100 parts by mass of all the monomers used, sodium hydroxide and potassium hydroxide can be 0.01 to 2.0 parts by mass.

[0045] (Reducing agent) In the emulsion polymerization process, a reducing agent can be added. Examples of the reducing agent include potassium metabisulfite, potassium sulfite, potassium bisulfite, potassium phosphate, potassium hydrogen phosphate, sodium bisulfite, sodium sulfate, and thiourea dioxide. The addition amount of the reducing agent can be 0.005 to 3.0 parts by mass relative to 100 parts by mass of the raw material monomers used in the polymerization process.

[0046] (Polymerization conversion rate) In the emulsion polymerization of chloroprene polymers and the like, the polymerization conversion rate of the raw material monomers is preferably 50% by mass or more and less than 90% by mass, more preferably 60 to 85% by mass. By setting the polymerization conversion rate to 50% by mass or more, it is possible to prevent a decrease in the solid content concentration of the chloroprene polymer latex, which may lead to an increase in the load of the drying process after the adhesive is applied and difficulty in making the adhesive layer uniform. In addition, it is possible to prevent problems such as deterioration of odor, adhesive strength, and adhesive force caused by the remaining chloroprene monomer. By setting the polymerization conversion rate to less than 90% by mass, it is possible to prevent an increase in the molecular weight distribution caused by an increase in the side chains and an increase in the molecular weight in the chloroprene polymer, and to prevent deterioration of the initial adhesive strength. The polymerization conversion rate (mass%) is obtained by [(total mass of polymer / total mass of monomer) × 100]. Hereinafter, the polymerization conversion rate may sometimes be simply referred to as the polymerization rate.

[0047] (Polymerization temperature) The chloroprene polymer can be polymerized, for example, in the range of 0 to 45°C, and particularly preferably at a low temperature of 5 to 20°C. It is known that in the chloroprene polymer, the trans-1,4 bond accounts for more than 85%, and its molecular structure has relatively high regularity. Due to the high regularity of this molecular structure, the chloroprene polymer has the properties of a typical crystalline polymer. In particular, by polymerizing at a low temperature of 5 to 20°C, the ratio of the trans-1,4 bond in the polychloroprene molecule is further increased, the crystallization rate can be further increased, and more sufficient adhesive strength can be achieved when used as an aqueous adhesive.

[0048] (Polymerization terminator) Generally, when manufacturing a chloroprene polymer, for the purpose of obtaining a polymer with the desired molecular weight and distribution, when the predetermined polymerization rate is reached, a polymerization terminator is added to terminate the reaction. There is no particular limitation on the polymerization terminator, and phenothiazine, p-tert-butylcatechol, hydroquinone, methyl hydroquinone, diethylhydroxylamine, etc. can be used.

[0049] (Nonionic emulsifier) According to a manufacturing method of a chloroprene polymer latex according to an embodiment of the present invention, it may include a step of adding an emulsifier after polymerization termination. As the emulsifier, nonionic emulsifiers can be cited. The types of nonionic emulsifiers are as described above. The addition amount of the nonionic emulsifier may be 0.005 to 0.40 parts by mass relative to 100 parts by mass of the chloroprene-based polymer. The addition amount of the nonionic emulsifier is, for example, 0.005, 0.007, 0.009, 0.01, 0.02, 0.03, 0.05, 0.07, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40 parts by mass, and may also be within the range between any two values exemplified herein. In addition, the emulsifier may be added before the solid content concentration is adjusted or after the solid content concentration is adjusted.

[0050] (Solid content concentration) In the method for producing a chloroprene-based polymer latex according to an embodiment of the present invention, there may be a step of removing unreacted monomers by a concentration method such as vacuum distillation. The solid content concentration of the chloroprene-based polymer latex is not particularly limited and can be adjusted to 40 to 65% by mass. The solid content concentration of the chloroprene-based polymer latex can be controlled by adjusting the ratio of solvents such as water during the emulsion polymerization of the chloroprene-based polymer and a concentration step such as vacuum distillation. The chloroprene-based polymer latex obtained by the above method can be directly used as a chloroprene-based polymer latex composition, or further additives can be added to form a chloroprene-based polymer latex composition.

[0051] 1.5 Physical properties of the chloroprene-based polymer latex composition In the chloroprene-based polymer latex composition according to an embodiment of the present invention, preferably, relative to 100 parts by mass of the chloroprene-based polymer latex composition, a binder composition containing 25 parts by mass of an acrylic emulsion and 11 parts by mass of a pH regulator has an initial adhesion strength 1 of 2.5 N / cm measured by the following method 2 and / or an initial adhesion strength 2 of 5.9 N / cm 2 or more.

[0052] The initial adhesion strength 1 is, for example, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0 N / cm 2 and may also be within the range between any two values exemplified herein.

[0053] The initial adhesion strength 2 is, for example, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0 N / cm2 , or within a range between any two values exemplified herein.

[0054] <Initial Adhesive Strength> Take two polyurethane foams with a density of 30 kg / m 3 (thickness 20 mm × length 50 mm × width 50 mm) as adherends, and spray the adhesive on each adherend at 70 g / m 2 in an environment of 23°C. After coating, while the adhesive is in an undried state, stack the bonding surfaces of the polyurethane foams on top of each other, compress the adherend (laminate) with a thickness of 40 mm to 20 mm and hold for 10 seconds. After that, place it in an environment of 23°C for 1 minute (Initial Adhesive Strength 1) or 15 minutes (Initial Adhesive Strength 2), and then immediately conduct a tensile test in a direction perpendicular to the bonding surface using a tensile testing machine (TENSILON manufactured by A&D; tensile speed: 200 mm / min) to measure the adhesive strength.

[0055] 2. Adhesive Composition The adhesive composition according to the present invention may contain the above-mentioned chloroprene-based polymer latex composition.

[0056] 2.1 pH Regulator The adhesive composition according to an embodiment of the present invention may contain a pH regulator. By adding a pH regulator, the initial adhesive strength and storage stability can be further improved. As the pH regulator, weak acids and buffer solutions can be used. Specifically, at least one compound selected from hydroxy acids such as citric acid and glycolic acid, boric acid, amino acids, etc. is preferably used, and amino acids are more preferred. As amino acids, glycine, alanine, threonine, and proline can be listed. Considering cost, adhesive performance, ease of handling, etc., glycine is more preferred.

[0057] The adhesive composition according to an embodiment of the present invention preferably contains 1 to 20 parts by mass of a pH regulator relative to 100 parts by mass of the solid content of the chloroprene-based polymer latex composition. The content of the pH regulator is, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 parts by mass, or within a range between any two values exemplified herein. The pH regulator can be used alone or in combination of two or more.

[0058] 2.2 Polymer Emulsion The chloroprene-based polymer latex composition and the adhesive composition according to an embodiment of the present invention may contain a polymer emulsion (latex containing polymers other than chloroprene-based polymers).

[0059] As the polymer emulsion, one or more selected from acrylic emulsions, polyurethane emulsions, styrene / butadiene rubber latexes, acrylonitrile / butadiene rubber latexes, natural rubber latexes, etc. can be cited, and an acrylic emulsion is preferably contained. The acrylic emulsion can be obtained by copolymerizing (meth)acrylate with a monomer as a functional group, a monomer as a crosslinking group, and / or other copolymerizable monomers as required.

[0060] In the chloroprene-based polymer latex composition and / or adhesive composition according to an embodiment of the present invention, the content of the polymer emulsion relative to 100 parts by mass of the solid content is, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45 parts by mass, and can also be within the range between any two values exemplified herein. The polymer emulsion can be used alone or in combination of two or more. The adhesive composition according to an embodiment of the present invention can maintain the initial adhesive strength and further improve its storage stability and the texture (hardness) of the adhesive layer by containing a polymer emulsion (especially an acrylic emulsion).

[0061] The adhesive composition according to an embodiment of the present invention may contain known components, and for example, a tackifier, an acid acceptor, an antioxidant, a filler, a pigment, a colorant, a wetting agent, a defoaming agent, a thickening agent, etc. can be contained. As the tackifier, phenolic resins, terpene resins, rosin derivative resins, petroleum-based hydrocarbons, etc. can be cited.

[0062] The adhesive composition according to an embodiment of the present invention preferably has an initial adhesive strength 1 of 2.5 N / cm measured by the above method 2 and / or an initial adhesive strength 2 of 5.9 N / cm 2 or more.

[0063] The initial adhesive strength 1 is, for example, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0 N / cm 2 , and can also be within the range between any two values exemplified herein.

[0064] The initial adhesive strength 2 is, for example, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0 N / cm 2 , and can also be within the range between any two values exemplified herein.

[0065] An adhesive composition according to an embodiment of the present invention, wherein the adhesive is preferably an aqueous adhesive, and more preferably used as a one-component aqueous adhesive. The adhesive composition according to an embodiment of the present invention can preferably be used as a spray-type adhesive, and particularly preferably as a spray-type adhesive for bonding the following adherends.

[0066] Examples of the adherends to be bonded by the adhesive composition according to an embodiment of the present invention include foams (foams) made of materials such as polyurethane, ethylene-vinyl acetate copolymer, and polyethylene, wood, cloth, and fabrics. The adhesive composition according to an embodiment of the present invention can be used for polyurethane foam, and at least one of the adherends can be polyurethane foam. For example, it is suitable for bonding between polyurethane foams, between polyurethane foam and wood, between polyurethane foam and cloth, and for example, suitable for bonding in the manufacture of furniture including polyurethane foam parts.

Examples

[0067] Hereinafter, the present invention will be described in more detail based on examples and comparative examples, but the present invention is not limited to these examples.

[0068] <Production of chloroprene polymer latex> In a polymerization kettle with an internal volume of 10 L, 100 parts by mass of chloroprene (monomer), 0.1 part by mass of n-dodecyl mercaptan, 90 parts by mass of pure water, 3.5 parts by mass of potassium rosinate A (including conjugated resin acid, self-made product), 0.55 part by mass of potassium hydroxide, 0.30 part by mass of sodium salt of β-naphthalenesulfonic acid formaldehyde condensate (trade name "Demol N", manufactured by Kao Corporation), and 0.3 part by mass of NaHSO3 were added. Potassium persulfate as a polymerization initiator and thiourea dioxide as a reducing agent were added, and polymerization was carried out at a polymerization temperature of 10 °C under a nitrogen stream. When the polymerization conversion rate reached 83% by mass, polymerization was terminated by adding phenothiazine as a polymerization terminator to obtain the latex before distillation. Polyoxyethylene styrenyl phenyl ether (trade name "Noigen EA-137", manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as a nonionic emulsifier was added, and the unreacted monomer was removed from the latex before distillation by vacuum distillation to obtain the distilled latex A containing a chloroprene polymer (solid content: 55% by mass).

[0069] Using the components and conditions shown in Tables 1 and 2, in addition, the same operations as for latex A were carried out to obtain latexes B to E (solid content 55%) (disproportionated potassium rosinate: trade name "RON DIS K-25", manufactured by Arakawa Chemical Industries, Ltd.).

[0070] <Contents of conjugated resin acid component and non-conjugated resin acid component in rosin acid component> Determine the contents of conjugated resin acid components and non-conjugated resin acid components in the above-mentioned potassium rosin A. First, dissolve rosin acid in an ethanol / toluene azeotropic mixture (ETA solution) specified in JIS K 6229, and perform hydrochloric acid treatment to obtain a solution (rosin acid: 1.5% by mass). Perform gas chromatography analysis using this solution under the following conditions.

[0071] [Conditions of Gas Chromatography] · Gas chromatography-mass spectrometry: Trade name "JEOL Jms-Q1050GC", manufactured by JEOL Ltd. · Chromatographic column used: FFAP (Film thickness 0.3 μm) · Column temperature: 200 °C (held for 90 minutes) → 250 °C · Heating rate: 10 °C / min · Injection port temperature: 270 °C · Injection volume: 1 μL · Interface temperature: 270 °C · Ion source temperature: 270 °C · Ionization current: 50 μA · Ionization voltage: 70 eV · Detector voltage: -1000 V · Ionization method: EI method

[0072] From the measurement results of gas chromatography, obtain the peak areas of abietic acid components (abietic acid and its salts. The same applies to other resin acids), neoabietic acid components, palustric acid components, and levopimaric acid components, which are each conjugated resin acid components. At the same time, also obtain the peak areas of dehydroabietic acid components, pimaric acid components, isopimaric acid components, and dihydroabietic acid components, which are each non-conjugated resin acid components. The area percentage of each component relative to the total peak area is regarded as the content of each component, thereby determining the contents of conjugated resin acid components and non-conjugated resin acid components.

[0073] In rosin acid A, in terms of the area percentage of conjugated resin acid components, the abietic acid component is 38.5%, the neoabietic acid component is 1.2%, the palustric acid component is 2.3%, and the levopimaric acid component is 2.6%, and the total area of conjugated resin acid components is 44.6%. In terms of the area percentage of non-conjugated resin acid components, the dehydroabietic acid component is 33.5%, the pimaric acid component is 8.0, and the dihydroabietic acid component is 5.2%, and the total area of non-conjugated resin acid components is 46.7%.

[0074] The disproportionated potassium rosin mentioned above was also analyzed by gas chromatography. As a result, no abietic acid component, neoabietic acid component, palustric acid component, or levopimaric acid component was detected. The area percentages of the non-conjugated resin acid components were 68.8% for dehydroabietic acid component, 0.5% for pimaric acid component, and 21.1% for dihydroabietic acid component. The total area of the non-conjugated resin acid components was 90.4%.

[0075] <Content of polyoxyethylene styrenyl phenyl ether relative to 100 parts by mass of the chloroprene-based polymer> Using a JNM-ECX-400 (400 MHz, FT type) manufactured by JEOL Ltd., the sample solution obtained by dissolving 1.0 mg of the internal standard substance sodium trimethylsilyl propionate d4 (TSP-d4) and approximately 30 mg of polyoxyethylene styrenyl phenyl ether (trade name "Noigen EA-137", manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) in 1.0 mL of heavy water was measured for its 1 1H-NMR spectrum. When using heavy water (4.65 ppm) as the reference substance for chemical shift, the peak area I from TSP-d4 of -0.50 to 0.50 ppm was obtained TSP and the peak area I from polyoxyethylene styrenyl phenyl ether of 3.00 to 4.00 ppm EA-137 . The unknown M was calculated according to the following relationship EA-137 / H EA-137 . Where W represents mass, M represents molecular weight, I represents signal integral value, and H represents the number of signals H W TSP / M TSP :W EA-137 / M EA-137 =I TSP / H TSP :I EA-137 / H EA-137 The solid component obtained by freeze-drying the above-mentioned chloroprene-based polymer latex composition was extracted with an ethanol / toluene azeotropic mixture (ETA solution) specified in JIS K6229. After filtering to remove the solid component to obtain a solution, the solvent was removed to obtain a dried product. At this time, the ratio of the mass of the obtained dried product to the mass of the solid component of the chloroprene-based polymer latex composition was used as the ETA extraction rate Using a JNM-ECX-400 (400 MHz, FT type) manufactured by JEOL Ltd., the 1 1H-NMR spectrum of the sample solution obtained by dissolving approximately 30 mg of the above-mentioned dried product and 1.0 mg of TSP-d4 in 1.0 mL of heavy water was measured. When using heavy water (4.65 ppm) as the reference substance for chemical shift, the peak area I from TSP of -0.50 to 0.50 ppm was obtained TSP, the peak area I of 3.00 to 4.00 ppm from polyoxyethylene styrenyl phenyl ether x . The mass W of polyoxyethylene styrenyl phenyl ether contained in the sample solution was calculated according to the following relationship x . W TSP / M TSP : W x / M EA-137 =I TSP / H TSP : I x / H EA-137 The ratio C of the mass of polyoxyethylene styrenyl phenyl ether to the mass of the solid content of the chloroprene-based polymer latex composition was calculated by the following formula. C(%) = W x (mg) / mass of dried product (mg) × 100 × ETA extraction rate (%) The mass parts of polyoxyethylene styrenyl phenyl ether relative to 100 mass parts of the chloroprene-based polymer were calculated from the obtained value of C, and the values in Table 1 were obtained.

[0076] <Measurement conditions for nuclear magnetic resonance analysis (1H-NMR)> · Measurement mode: Non-decoupling · Flip angle: 45 degrees · Waiting time: 4.3 seconds · Sample rotation speed: 12 Hz · Window processing: Exponential function · Number of accumulations: 32 · Measurement temperature: 30 °C

[0077] <Toluene-insoluble component> 1 g of the chloroprene-based polymer obtained by freeze-drying the above chloroprene-based polymer latex was cut into squares with a side length of 2 mm to obtain a test sample. After adding this test sample to a conical flask, the test sample was dissolved with 80 g of toluene over 16 hours. Then, after centrifugation, the gel component (insoluble component) was separated using a 200-mesh metal wire mesh. After that, the gel component was dried and the mass of the dried product was measured. When the freeze-dried latex is denoted as A g and the gel component (insoluble component) separated from the mixture obtained by dissolving with toluene is denoted as B g, the toluene-insoluble component in the chloroprene-based polymer is obtained by the following formula. Toluene-insoluble component (gel component) = B / A × 100 (%) The results are shown in Table 1 and Table 2.

[0078] <Average particle size> The above-mentioned chloroprene-based polymer latex was diluted with distilled water to adjust the solid content concentration to 0.01% by mass, and the average particle size was determined using an ELSZ Series (manufactured by Otsuka Electronics Co., Ltd.). Here, the average particle size of the latex was the value obtained by the cumulant method using the autocorrelation function obtained by the photon correlation method in the dynamic light scattering method. The results are shown in Tables 1 and 2.

[0079] <Freezing stability (-5°C)> 10 mL of the prepared chloroprene-based polymer latex was placed in a polypropylene test tube with a diameter of 18 mm and a length of 18 cm and sealed. Then it was placed in a bench-top low-temperature constant temperature water bath and stored at -5°C, and the appearance and viscosity changes after 1 day were recorded. The test tube was tilted, and those without viscosity change were marked as ○, those with slightly changed viscosity were marked as △, and those with the liquid level not moving and solidified were marked as ×. The results are shown in Tables 1 and 2.

[0080] <Preparation of aqueous adhesive> Relative to 100 parts by mass of the solid content of the above-obtained chloroprene-based polymer latex composition, 25 parts by mass of an acrylic emulsion (trade name "Acronal Proof 1299", BASF) and 11 parts by mass of glycine as a pH regulator were added, and an aqueous adhesive was prepared by stirring with a San-ichi motor. The initial adhesive strength of the obtained aqueous adhesive was measured by the following method, and the measurement results are shown in Tables 1 and 2.

[0081] [Initial adhesive strength] Two polyurethane foams with a density of 30 kg / m 3 (thickness 20 mm × length 50 mm × width 50 mm) were used as adherends, and the adhesive was sprayed on each adherend at 70 g / m 2 at 23°C. After coating, the adhesive surfaces of the polyurethane foams were overlapped with each other in the state where the adhesive was not dried, and the adherend with a thickness of 40 mm (laminate) was compressed to 20 mm and held for 10 seconds. After that, it was left at 23°C for 1 minute (initial adhesive strength 1) or 15 minutes (initial adhesive strength 2), and then a tensile test was immediately carried out in the direction perpendicular to the adhesive surface using a tensile testing machine (TENSILON manufactured by A&D; tensile speed 200 mm / min) to measure the adhesive strength.

[0082]

Table 1

[0083]

Table 2

[0084] As shown in the table, it can be confirmed that the adhesive composition containing the chloroprene polymer latex composition of the present invention has improved initial adhesion strength, especially the adhesive force in the wet state, and is suitable as an adhesive for applications requiring excellent initial adhesion strength and excellent freeze-thaw stability, and is particularly suitable as a spray-type adhesive for bonding polyurethane foam.

Claims

1. A chloroprene-based polymer latex composition comprising a chloroprene-based polymer and a nonionic emulsifier, The chloroprene-based polymer latex composition contains 0.005 to 0.40 parts by mass of the nonionic emulsifier relative to 100 parts by mass of the chloroprene-based polymer, The average particle size of the chloroprene-based polymer is 80 to 160 nm, and the toluene-insoluble component is 30% by mass or less.

2. The chloroprene-based polymer latex composition according to claim 1, Among them, The nonionic emulsifier includes at least one selected from the group consisting of polyoxyalkylene phenyl ether-based emulsifiers, polyoxyalkylene alkyl ether-based emulsifiers, polyoxyethylene sorbitan fatty acid ester-based emulsifiers, polyoxyethylene sorbitol fatty acid ester-based emulsifiers, sorbitan fatty acid ester-based emulsifiers, glycerol fatty acid ester-based emulsifiers, polyoxyethylene alkylamine-based emulsifiers, polyoxyethylene fatty acid ester-based emulsifiers, and alkyl alkanolamide-based emulsifiers.

3. An adhesive composition containing the chloroprene-based polymer latex composition according to claim 1 or 2.

4. The adhesive composition according to claim 3, which contains a pH adjuster.

5. The adhesive composition according to claim 3, which is an adhesive composition for polyurethane foam.

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