Chloroprene polymer latex composition and adhesive composition

Abstract

Provided are: a chloroprene polymer latex composition which is capable of obtaining an adhesive composition having excellent sprayability; and an adhesive composition which contains the chloroprene polymer latex composition. According to the present invention, provided is a chloroprene polymer latex composition containing a chloroprene polymer, the chloroprene polymer latex composition for a test being obtained by adjusting the chloroprene polymer latex composition to a solid content concentration of 55 mass%, and the chloroprene polymer latex composition having a mechanical stability test under conditions of a load of 10 kg and a rotation speed of 1000 rpm, the occurrence rate of agglomerates in the chloroprene polymer latex composition for tests is 0.01-1.00%, and the viscosity of the chloroprene polymer latex composition for tests, as measured by a B-type viscometer at 23 DEG C and 6 rpm, is 22-100 mPa * s.

Description

Technical Field

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

[0002] Adhesives containing chloroprene-based polymers can obtain high adhesive strength with 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-based polymer latexes are being developed.

[0003] For example, Patent Document 1 discloses a chloroprene-based polymer latex and an adhesive composition containing the chloroprene-based polymer latex. The chloroprene-based 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-based polymer latex) of a polyoxyalkylene derivative represented by a specific formula. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-160295 Summary of the Invention Problems to be Solved by the Invention

[0005] However, aqueous adhesives containing existing chloroprene-based polymer latex compositions may have insufficient sprayability, and it is difficult to obtain an aqueous adhesive having excellent initial adhesive strength and excellent sprayability. The present invention has been made in view of the above circumstances, and aims to provide a chloroprene-based polymer latex composition capable of obtaining an adhesive composition having excellent initial adhesive strength and sprayability, and an adhesive composition containing the chloroprene-based polymer latex composition. Solutions to the Problems

[0006] According to the present invention, there is provided a chloroprene-based polymer latex composition containing a chloroprene-based polymer. The chloroprene-based polymer latex composition is adjusted to a solid content concentration of 55% by mass to obtain a test chloroprene-based polymer latex composition. In a mechanical stability test under the conditions of a load of 10 kg and a rotation speed of 1000 rpm, the coagulum occurrence rate of the test chloroprene-based polymer latex composition is 0.01 to 1.00%, and at 23°C and 6 rpm, the viscosity of the test chloroprene-based polymer latex composition measured with a B-type viscometer is 22 to 100 mPa·s.

[0007] The inventors of the present invention have conducted in-depth research and found that in a test neoprene polymer latex composition obtained by adjusting the neoprene polymer latex composition to a specific solid content concentration, by adjusting the coagulum incidence rate and viscosity in the mechanical stability test to within a specific numerical range, a neoprene polymer latex composition capable of obtaining an adhesive composition having excellent initial adhesion strength and sprayability can be prepared, thus completing the present invention.

[0008] The following exemplify various embodiments of the present invention. The embodiments shown below can be combined with each other. [1] A neoprene polymer latex composition comprising a neoprene polymer, wherein the neoprene polymer latex composition is adjusted to a solid content concentration of 55% by mass to obtain a test neoprene polymer latex composition. In the mechanical stability test under the conditions of a load of 10 kg and a rotation speed of 1000 rpm, the coagulum incidence rate of the test neoprene polymer latex composition is 0.01 to 1.00%, and at 23 °C and 6 rpm, the viscosity of the test neoprene polymer latex composition measured with a B-type viscometer is 22 to 100 mPa·s. [2] The neoprene polymer latex composition according to [1], wherein, based on 100 parts by mass of the neoprene polymer, the neoprene polymer latex composition contains 0.5 to 3.5 parts by mass of a conjugated resin acid. [3] The neoprene polymer latex composition according to [1] or [2], wherein the toluene-insoluble component of the neoprene polymer is 30% by mass or less. [4] The neoprene polymer latex composition according to any one of [1] to [3], wherein, based on 100 parts by mass of the neoprene polymer, the neoprene polymer latex composition contains 0.40 parts by mass or less of a nonionic surfactant. [5] The neoprene polymer latex composition according to any one of [1] to [4], wherein the neoprene polymer latex composition, an acrylic latex containing an acrylic polymer, and a pH regulator are mixed to prepare a test adhesive composition containing 25 parts by mass of the acrylic polymer and 11 parts by mass of the pH regulator based on 100 parts by mass of the neoprene polymer. In the mechanical stability test under the conditions of a load of 1.0 kg and a rotation speed of 1000 rpm, the coagulum incidence rate of the test adhesive composition is 1.0 to 10.0%, and at 23 °C and 6 rpm, the viscosity of the test adhesive composition measured with a B-type viscometer is 100 to 5000 mPa·s. [6] An adhesive composition containing a chloroprene polymer latex composition as described in any one of [1] to [5]. [7] The adhesive composition as described in [6], wherein in the mechanical stability test under the conditions of a load of 1.0 kg and a rotation speed of 1000 rpm, the incidence rate of coagulum is 1.0 to 10.0%, and at 23 °C and 6 rpm, the viscosity measured with a B-type viscometer is 100 to 5000 mPa·s. [8] The adhesive composition as described in [6] or [7], which is an adhesive composition for polyurethane foam. Effects of the Invention

[0009] According to the chloroprene polymer latex composition of the present invention, an adhesive composition having excellent sprayability can be obtained. Specifically, the adhesive composition containing the chloroprene polymer latex composition of the present invention has moderate fluidity, is not easily blocked and is easy to spray, and there are few adverse conditions such as infiltration and dripping of the adhesive composition on the adherend. The adhesive composition exhibits good coating properties on the adherend. The adhesive composition containing the chloroprene polymer latex composition of the present invention can be suitably used as, for example, a spray-type adhesive used in the bonding of polyolefin resins, foams, especially polyurethane foam. Detailed Embodiments

[0010] The embodiments of the present invention are exemplified 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 Polymer Latex Composition The chloroprene polymer latex composition according to the present invention contains a chloroprene polymer. The chloroprene polymer latex composition is adjusted to a solid content concentration of 55% by mass to obtain a test chloroprene polymer latex composition. In the mechanical stability test under the conditions of a load of 10 kg and a rotation speed of 1000 rpm, the incidence rate of coagulum of the test chloroprene polymer latex composition is 0.01 to 1.00%, and at 23 °C and 6 rpm, the viscosity of the test chloroprene polymer latex composition measured with a B-type viscometer is 22 to 100 mPa·s.

[0012] 1.1 Chloroprene Polymer and Chloroprene Polymer Latex In the present invention, a chloroprene-based polymer latex means a latex containing a chloroprene-based polymer. Additionally, a chloroprene-based polymer means a polymer containing monomer units derived from 2-chloro-1,3-butadiene (hereinafter also referred to as chloroprene monomer), including homopolymers of chloroprene monomer and copolymers 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, etc.

[0013] In the chloroprene-based polymer latex composition according to one embodiment of the present invention, when the chloroprene-based polymer contained in the chloroprene-based 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-based polymer latex composition according to one embodiment of the present invention may contain one type of chloroprene-based polymer or two or more types of chloroprene-based polymers. The chloroprene-based polymer latex composition according to one embodiment of the present invention preferably contains a homopolymer of chloroprene monomer. In the chloroprene-based polymer latex composition according to one embodiment of the present invention, relative to 100% by mass of the solid content of the chloroprene-based polymer latex contained in the chloroprene-based 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 the homopolymer of chloroprene monomer in the chloroprene-based polymer latex composition according to one embodiment of the present invention, the contact property, heat-resistant adhesiveness, and initial adhesiveness of the adhesive composition containing the chloroprene-based polymer latex composition can be further improved.

[0015] <Toluene-insoluble component> In the chloroprene-based polymer according to one embodiment of the present invention, the toluene-insoluble component is preferably 30% by mass or less, more preferably 10% by mass or less. 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. In the present invention, the toluene-insoluble component refers to the content of the gel component that is insoluble in toluene solvent in the chloroprene-based polymer. In addition, the sol refers to the component that is soluble in toluene solvent. It is speculated that for the chloroprene-based polymer according to an embodiment of the present invention, when the toluene-insoluble component (gel component) is within the above numerical range, the sol with excellent molecular mobility is moderately contained, and the molecular chains of the chloroprene-based polymer at the bonding interface rapidly fuse, thereby instantaneously exhibiting the bonding strength and being able to exhibit more excellent initial bonding strength.

[0016] 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 from the following formula, specifically, it can be obtained by the method described in the examples. Toluene-insoluble component (gel component) = B / A × 100 (%)

[0017] The toluene-insoluble component can be controlled by adjusting the polymerization conditions during the manufacture of the chloroprene-based polymer latex, such as adjusting the types and amounts of polymerization initiators and chain transfer agents, polymerization temperature, polymerization time, polymerization rate, and other manufacturing conditions.

[0018] In addition, when the chloroprene-based polymer latex composition contains two or more chloroprene-based polymers, the toluene-insoluble component of the mixture formed by mixing two or more chloroprene-based polymers is preferably within the above numerical range.

[0019] <Average particle size> The average particle size of the chloroprene-based polymer latex according to an embodiment of the present invention is preferably 160 nm or less. The average particle size is, for example, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160 nm, and can also be within the range between any two values exemplified here.

[0020] The average particle size of the chloroprene-based polymer latex can be the value obtained by the cumulant method using the autocorrelation function obtained 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 manufacture of the chloroprene-based polymer latex, such as adjusting the types and amounts of emulsifiers, polymerization temperature, polymerization time, polymerization rate, and other manufacturing conditions, the average particle size of the chloroprene-based polymer latex can be controlled.

[0021] 1.2 Conjugated resin acid The chloroprene-based polymer latex composition according to an embodiment of the present invention may contain 3.5 parts by mass or less of a conjugated resin acid, preferably 0.5 to 3.5 parts by mass, more preferably 1.4 to 3.0 parts by mass, based on 100 parts by mass of the chloroprene-based polymer. The content of the conjugated resin acid based on 100 parts by mass of the chloroprene-based polymer is, for example, 0, 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, 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. In addition, according to an embodiment of the present invention, the chloroprene-based polymer latex composition of the present invention may not contain a conjugated resin acid.

[0022] The chloroprene-based polymer latex composition according to an embodiment of the present invention may contain 0.5 to 6.0 parts by mass of a non-conjugated resin acid based on 100 parts by mass of the chloroprene-based polymer. The content of the non-conjugated resin acid based on 100 parts by mass of the chloroprene-based 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.

[0023] In the chloroprene-based polymer latex composition according to an embodiment of the present invention, when the total content of the conjugated resin acid and the non-conjugated resin acid in the chloroprene-based polymer latex composition is set to 100% by mass, the content ratio of the conjugated resin acid may be 5% by mass or more. The content ratio of the conjugated resin acid is, for example, 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.

[0024] Conjugated resin acids mean resin acids (abietic acids) having conjugated double bonds in the resin acids. Examples of conjugated resin acids include abietic acid, neoabietic acid, palustric acid, and levopimaric acid. The conjugated resin acids preferably contain at least one of abietic acid and palustric acid, and more preferably contain abietic acid. In addition, examples of non-conjugated resin acids include dehydroabietic acid, pimaric acid, isopimaric acid, dihydroabietic acid, dihydropimaric acid, ring-opening dehydroabietic acid, deisopropyl dehydroabietic acid, and demethyl dehydroabietic acid.

[0025] 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 salts. In the polymerization of the chloroprene-based polymer, rosin acid (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 salts, conjugated resin salts, and non-conjugated resin salts. In addition, the emulsion polymerization method using rosin acid, etc. is mostly carried out under strongly alkaline conditions, and in the strongly alkaline chloroprene-based polymer latex, rosin acid, conjugated resin acids, and non-conjugated resin acids mostly exist in the form of salts. Examples of salts include alkali metal salts such as potassium salts and sodium salts. Examples of the compounds that form salts with rosin acid, conjugated resin acids, and non-conjugated resin acids include potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate. Conjugated resin salts include potassium abietate, potassium neoabietate, potassium palustrate, potassium levopimarate, sodium abietate, sodium neoabietate, sodium palustrate, and sodium levopimarate.

[0026] The content of the conjugated resin acid can be calculated by the following method: The solid component of the chloroprene-based polymer obtained by freeze-drying the chloroprene-based polymer latex is extracted with an ethanol / toluene azeotropic mixture (ETA solution) specified in JIS K 6229 and subjected to hydrochloric acid treatment to obtain an extract, which is subjected to gas chromatography analysis. From the measurement results of the 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 by the method described in the examples.

[0027] By adjusting the type and amount of the emulsifier formulated in the chloroprene-based polymer latex composition, especially by adjusting the type and amount of rosin acid used in the emulsion polymerization of the chloroprene-based polymer, the content of the conjugated resin acid in the chloroprene-based polymer latex composition can be controlled.

[0028] In the emulsion polymerization of chloroprene polymers, rosin acid and its alkali metal salts are used as emulsifiers. However, when using rosin acid containing conjugated resin acid having a conjugated double bond as rosin acid, the polymerization is inhibited. In addition, there may be cases where the stability of the obtained chloroprene polymer latex is insufficient or the adhesiveness is insufficient. From the above viewpoints, in the emulsion polymerization of chloroprene polymers (especially in the emulsion polymerization of chloroprene polymers for adhesive use), disproportionated rosin acid, especially alkali metal salts of disproportionated rosin, is sometimes used as an emulsifier. In one embodiment of the present invention, an emulsifier containing conjugated resin acid can be used in the emulsion polymerization of chloroprene polymers. By using an emulsifier containing conjugated resin acid, the mechanical stability and viscosity of the obtained chloroprene polymer latex composition can be easily adjusted to an appropriate range.

[0029] The chloroprene polymer latex composition according to one embodiment of the present invention may contain rosin acid having a content of conjugated resin acid of 5% by mass or more. The content of conjugated resin acid in rosin acid is, for example, 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.

[0030] 1.3 Nonionic surfactant In the chloroprene polymer latex composition according to one embodiment of the present invention, the content of the nonionic surfactant is preferably 0.40 parts by mass or less, more preferably 0.30 parts by mass or less, relative to 100 parts by mass of the chloroprene polymer. The content of the nonionic surfactant is, for example, 0, 0.05, 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. The chloroprene polymer latex composition according to one embodiment of the present invention may not contain a nonionic surfactant. In the chloroprene polymer latex composition of the present invention, by containing a nonionic surfactant within the above numerical range, the mechanical stability and viscosity of the obtained chloroprene polymer latex composition can be more easily adjusted to an appropriate range. The content of the nonionic surfactant relative to 100 parts by mass of the chloroprene polymer can be obtained by the method described in the examples.

[0031] Examples of the nonionic surfactant include surfactants such as polyoxyalkylene phenyl ether type, polyoxyalkylene alkyl ether type, polyoxyethylene sorbitan fatty acid ester type, polyoxyethylene sorbitol fatty acid ester type, sorbitan fatty acid ester type, glycerol fatty acid ester type, polyoxyethylene alkylamine type, polyoxyethylene fatty acid ester type, and alkyl alkanolamide type. As the nonionic surfactant, it is preferably at least one of surfactants of the polyoxyalkylene phenyl ether type and the polyoxyalkylene alkyl ether type, more preferably at least one of surfactants of the polyoxyethylene phenyl ether type and the polyoxyethylene alkyl ether type, and further preferably contains a surfactant of the polyoxyethylene styrenyl phenyl ether type.

[0032] Surfactants of the polyoxyalkylene alkyl ether type and the polyoxyalkylene phenyl ether type can be represented as RO(EO) n (PO) m H. In the formula, R is a linear or branched alkyl group having 8 to 30 carbon atoms, or an unsubstituted or substituted phenyl group, preferably a linear or branched alkyl group having 8 to 12 carbon atoms, or an unsubstituted or substituted phenyl group, and 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, and PO represents an alkylene oxide having 3 or more carbon atoms such as a propylene oxide group or a butylene oxide 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.

[0033] In addition, the chloroprene polymer latex composition according to an embodiment of the present invention may also contain emulsifiers and dispersants other than conjugated resin acids, their salts, rosin acids, their salts, and nonionic surfactants. Regarding other emulsifiers and dispersants, they will be described in the subsequent description of the manufacturing method of the chloroprene polymer latex.

[0034] 1.5 Characteristics of the chloroprene polymer latex composition For the chloroprene polymer latex composition according to the present invention, the chloroprene polymer latex composition is adjusted to a solid content concentration of 55% by mass to obtain a test chloroprene polymer latex composition. In the mechanical stability test under the conditions of a load of 10 kg and a rotation speed of 1000 rpm, the coagulum occurrence rate of the test chloroprene polymer latex composition is 0.01 to 1.00%.

[0035] In the mechanical stability test under the conditions of a load of 10 kg and a rotation speed of 1000 rpm, the incidence rate of agglomerates is 0.01 to 1.00%, preferably 0.01 to 0.70%. In the mechanical stability test under the conditions of a load of 10 kg and a rotation speed of 1000 rpm, the incidence rate of agglomerates is, for example, 0.01, 0.02, 0.03, 0.04, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00%, and can also be within the range between any two values exemplified herein. When the incidence rate of agglomerates in the mechanical stability test of the chloroprene-based polymer latex composition is above the above lower limit, the adhesive composition containing the chloroprene-based polymer latex composition is moderately emulsified and broken after coating, and sufficient initial adhesion strength can be exhibited. In addition, when the incidence rate of agglomerates in the mechanical stability test of the chloroprene-based polymer latex composition is below the above upper limit, the adhesive composition containing the chloroprene-based polymer latex composition can prevent precipitation due to the shear force during spraying, thereby preventing the deterioration of sprayability.

[0036] The incidence rate of agglomerates in the mechanical stability test of the chloroprene-based polymer latex composition can be measured using a test chloroprene-based polymer latex composition adjusted to a solid content concentration of 55% by mass. The incidence rate of agglomerates in the mechanical stability test of the chloroprene-based polymer latex composition can be obtained by applying a shear force to the test chloroprene-based polymer latex composition for 10 minutes under the conditions of a load of 10 kg and a rotation speed of 1000 rpm using a Maron test device, and evaluating the amount of agglomerates generated at this time. Specifically, it can be measured according to the method described in the examples.

[0037] It is considered that by adjusting the manufacturing conditions of the chloroprene-based polymer latex composition (for example, the types and amounts of emulsifiers and dispersants, the types and amounts of raw materials and reagents such as these, polymerization conditions, etc.), and adjusting the particle size, its distribution, and the tendency of emulsification breakdown of the chloroprene-based polymer in the obtained chloroprene-based polymer latex composition, the incidence rate of agglomerates in the mechanical stability test of the chloroprene-based polymer latex composition can be controlled.

[0038] For the chloroprene-based polymer latex composition according to the present invention, the viscosity of the test chloroprene-based polymer latex composition measured with a B-type viscometer at 23°C and 6 rpm is 22 to 100 mPa·s, more preferably 30 to 80 mPa·s. The viscosity under the conditions of 23°C and 6 rpm is, for example, 22, 23, 24, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100 mPa·s, and can also be within the range between any two values exemplified herein. By having a viscosity above the above lower limit, after spraying an adhesive composition containing a chloroprene-based polymer latex composition, it is possible to reduce the dripping of droplets adhering to the adherend. In addition, it is possible to prevent the droplets adhering to the adherend from penetrating deep into the adherend, which may lead to insufficient formation of the surface adhesive layer and insufficient adhesive strength. By having a viscosity below the above upper limit, it is possible to prevent poor spraying due to low fluidity, suppress a decrease in the coating amount or unevenness, and as a result, prevent a decrease in the adhesive strength.

[0039] The viscosity under the conditions of 23°C and 6 rpm can be measured using a test chloroprene-based polymer latex composition adjusted to a solid content concentration of 55% by mass. The viscosity under the conditions of 23°C and 6 rpm can be measured using a B-type viscometer, specifically, it can be measured by the method described in the examples.

[0040] It is considered that by adjusting the manufacturing conditions of the chloroprene-based polymer latex composition (for example, the types and amounts of emulsifiers and dispersants, the types and amounts of raw materials and reagents such as these, and polymerization conditions, etc.), and by adjusting the particle size and its distribution of the chloroprene-based polymer in the obtained chloroprene-based polymer latex composition, the viscosity under the conditions of 23°C and 6 rpm can be controlled. According to the chloroprene-based polymer latex composition of the present invention, by adjusting the coagulum occurrence rate and viscosity, it is possible to prepare an adhesive composition having excellent initial adhesive strength and excellent sprayability, that is, it is not easily clogged and is easy to spray, and there are no adverse conditions such as penetration and dripping of the adhesive composition to the adherend.

[0041] According to a chloroprene-based polymer latex composition of an embodiment of the present invention, a test adhesive composition preferably containing 25 parts by mass of an acrylic emulsion (acrylic latex containing an acrylic polymer) and 11 parts by mass of a pH regulator with respect to 100 parts by mass of the chloroprene-based polymer latex composition has an initial adhesive strength 1 of 3.0 N / cm measured by the following method 2 or more and / or an initial adhesive strength 2 of 6.0 N / cm 2 or more.

[0042] The initial adhesive strength 1 is, for example, 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 / cm2 , and it can also be within the range between any two values exemplified herein.

[0043] The initial adhesion strength 2 is, for example, 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 it can also be within the range between any two values exemplified herein.

[0044] <Initial adhesion strength> Two polyurethane foams with a density of 30 kg / m 3 (thickness 20 mm × length 50 mm × width 50 mm) are used as adherends, and the test adhesive composition is sprayed on each adherend at 70 g / m in an environment of 23°C. 2 After coating, the adhesive surfaces of the polyurethane foams are overlapped with each other while the test adhesive composition is in an undried state, and the adherend (laminate) with a thickness of 40 mm is compressed to 20 mm and maintained for 10 seconds. After that, it is left in an environment of 23°C for 1 minute (initial adhesion strength 1) or 15 minutes (initial adhesion strength 2), and then immediately a tensile test is carried out in a direction perpendicular to the adhesive surface with a tensile testing machine (TENSILON manufactured by A&D; tensile speed is 200 mm / min) to measure the adhesion strength.

[0045] For the chloroprene-based polymer latex composition according to an embodiment of the present invention, a test adhesive composition preferably containing 25 parts by mass of an acrylic emulsion (acrylic latex containing an acrylic polymer) and 11 parts by mass of a pH regulator with respect to 100 parts by mass of the chloroprene-based polymer latex composition has an aggregate incidence rate of 1.00 to 10.00% in a mechanical stability test under the conditions of a load of 1.0 kg and a rotation speed of 1000 rpm. The aggregate incidence rate of the test adhesive composition in the mechanical stability test under the conditions of a load of 1.0 kg and a rotation speed of 1000 rpm is, for example, 1.00, 2.00, 3.00, 4.00, 5.00, 6.00, 7.00, 8.00, 9.00, 10.00%, and it can also be within the range between any two values exemplified herein.

[0046] A test adhesive composition of a chloroprene-based polymer latex composition according to an embodiment of the present invention preferably contains 25 parts by mass of an acrylic emulsion (acrylic latex containing an acrylic polymer) and 11 parts by mass of a pH adjuster with respect to 100 parts by mass of the chloroprene-based polymer latex composition, and has a viscosity measured by a B-type viscometer at 23°C and 6 rpm of 100 to 5000 mPa·s. The viscosity of the test adhesive composition measured by a B-type viscometer at 23°C and 6 rpm is, for example, 100, 200, 300, 400, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000 mPa·s, and may also be within the range between any two values exemplified herein. The method for measuring and controlling the coagulum incidence rate and viscosity in the mechanical stability test of the test adhesive composition can be carried out according to the method for measuring and controlling the coagulum incidence rate and viscosity in the mechanical stability test of the adhesive composition described below.

[0047] 2. Manufacturing methods of chloroprene-based polymers, chloroprene-based polymer latexes, and chloroprene-based polymer latex compositions The manufacturing method of the chloroprene-based polymer latex according to the present invention is not particularly limited and can be manufactured by the following method. The manufacturing method of the chloroprene-based polymer latex according to an embodiment of the present invention may include an emulsion polymerization step in which 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., and a polymerization terminator is added when the target polymerization rate is reached, thereby obtaining a chloroprene-based polymer latex. In addition, additives such as a nonionic surfactant can be added to the chloroprene-based polymer latex thus obtained as needed. In addition, unreacted monomers can be removed by a concentration method such as vacuum distillation.

[0048] (Emulsifier) The emulsifier preferably contains conjugated resin acid. The addition amount of the conjugated resin acid may be 0 to 3.5 parts by mass relative to 100 parts by mass of all the monomers used. The addition amount of the conjugated resin acid relative to 100 parts by mass of all the monomers used is, for example, 0, 0.5, 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. Regarding the type of the conjugated resin acid, as described above, among the conjugated resin acids, there is also a conjugated resin acid present in the form of a conjugated resinate.

[0049] The emulsifier may also contain a non-conjugated resin acid. The addition amount of the non-conjugated resin acid may be 0.5 to 6.0 parts by mass relative to 100 parts by mass of all the monomers used. The addition amount of the non-conjugated resin acid relative to 100 parts by mass of all the monomers used 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.

[0050] When the total content of the conjugated resin acid and the non-conjugated resin acid in the emulsifier is set to 100% by mass, the content ratio of the conjugated resin acid may be 5% by mass or more. The content ratio of the conjugated resin acid is, for example, 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.

[0051] Generally, the disproportionated rosin acid used for the emulsion polymerization of chloroprene polymers is obtained by subjecting the raw material rosin acid to a disproportionation treatment, and the content of the conjugated resin acid in the disproportionated rosin acid is extremely small or does not contain the conjugated resin acid. In one embodiment of the present invention, rosin acids that have not been subjected to a disproportionation treatment, such as tall oil rosin, gum rosin, wood rosin, etc., raw material rosin acids, and rosin acids that have not been subjected to a treatment that completely modifies the conjugated resin acid (including the case where a part is modified into a non-conjugated resin acid and a part remains as a conjugated resin acid) can be used as the emulsifier.

[0052] As long as the content of the conjugated resin acid in the obtained chloroprene-based polymer latex composition is within the above numerical range, there is no particular limitation. The addition amount of rosin acid can be 3.0 to 7.0 parts by mass relative to 100 parts by mass of all monomers used. The addition amount of rosin acid 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 values exemplified herein.

[0053] The emulsifier may contain rosin acid with a conjugated resin acid content of 5% by mass or more. The content of conjugated resin acid in rosin acid is, for example, 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 values exemplified herein.

[0054] As an emulsifier used in the emulsion polymerization process, it may contain rosin acid including disproportionated rosin acid and / or its alkali metal salt. When the emulsifier contains raw material rosin acid and / or its salt, and disproportionated rosin acid and / or its salt, the emulsifier preferably contains 15% by mass or more of the raw material rosin acid and / or its salt relative to the total 100% by mass of these rosin acids. Relative to the total 100% by mass of rosin acid, the emulsifier may contain, for example, 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, and may also be within the range between any two values exemplified here. The emulsifier can also use an emulsifier and a dispersant other than rosin acid and / or its alkali metal salt. As an emulsifier and a 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 emulsifier used in the emulsion polymerization process may contain an emulsifier containing conjugated resin acid and an anionic emulsifier and dispersant. As the 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 or sulfonate-based anionic emulsifier and dispersant in combination. Specifically, alkyl sulfonates having 8 to 20 carbon atoms, alkyl aryl sulfates, condensates of sodium naphthalene sulfonate and formaldehyde, and sodium alkyl diphenyl ether disulfonate can be cited. The addition amount of the anionic emulsifier and dispersant is 0.05 to 5 parts by mass relative to 100 parts by mass of all the monomers used. The addition amount of the emulsifier and dispersant other than rosin acid and / or its alkali metal salt 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 here.

[0055] (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 preferable. Since the molecular weight and toluene-insoluble component are easily controlled, long-chain alkyl mercaptans are preferably used. The chain transfer agent can be used alone or in combination of two or more. The total addition amount of the chain transfer agent added during emulsion polymerization is preferably 0.005 to 0.12 parts by mass with respect 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, 0.1, 0.11, 0.12 parts by mass, and can also be within the range between any two values exemplified here.

[0056] (Initiator) As the initiator for polymerization, a usual radical polymerization initiator 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.

[0057] (Potassium hydroxide and sodium hydroxide) In the emulsion polymerization process, sodium hydroxide and / or potassium hydroxide can be used. With respect 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.

[0058] (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 0.01 to 3.0 parts by mass with respect to 100 parts by mass of the raw material monomers used in the polymerization process.

[0059] (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 coated and difficulty in making the adhesive layer uniform. In addition, it is possible to prevent problems such as deterioration of odor, adhesiveness, and bonding strength 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 branched chains and an increase in the molecular weight in the chloroprene polymer, and to prevent deterioration of the initial bonding 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.

[0060] (Polymerization temperature) The chloroprene polymer can be polymerized, for example, in the range of 0 to 45°C, and particularly preferably polymerized at a low temperature of 5 to 20°C. By polymerizing at a low temperature of 5 to 20°C, the ratio of trans-1,4 bonds in the polychloroprene molecule is further increased, the crystallization rate can be further increased, and more sufficient adhesiveness can be achieved when used as an aqueous adhesive.

[0061] (Polymerization terminator) Generally, when manufacturing a chloroprene polymer, for the purpose of obtaining a polymer with a 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.

[0062] (Nonionic surfactant) 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 a surfactant after polymerization termination. As the surfactant, nonionic surfactants can be cited. The types of nonionic surfactants are as described above. The addition amount of the nonionic surfactant is preferably 0.4 parts by mass or less relative to 100 parts by mass of the chloroprene polymer. The addition amount of the nonionic surfactant, for example, is 0, 0.05, 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. According to a manufacturing method of a chloroprene polymer latex according to an embodiment of the present invention, it may not include the step of adding a surfactant after polymerization termination. In addition, the surfactant can be added at the initial stage of polymerization such as during feeding, or can be added before or after the solid content concentration is adjusted.

[0063] (Solid component 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 component concentration of the chloroprene-based polymer latex is not particularly limited and can be adjusted to 40 to 65% by mass. The solid component 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 a chloroprene-based polymer latex composition can be prepared by further adding additives.

[0064] 3. Adhesive composition The adhesive composition according to the present invention may contain the above-mentioned chloroprene-based polymer latex composition.

[0065] 3.1 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 adhesion 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 the amino acids, glycine, alanine, threonine, and proline can be mentioned, and glycine is more preferably used in consideration of cost, adhesion performance, ease of handling, etc.

[0066] In the adhesive composition according to an embodiment of the present invention, 1 to 20 parts by mass of a pH regulator is preferably contained relative to 100 parts by mass of the solid component of the chloroprene-based polymer latex. 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, and can also be within the range between any two values exemplified here. The pH regulator can be used alone or in combination of two or more.

[0067] 3.2 Polymer emulsion The adhesive composition according to an embodiment of the present invention may contain a polymer emulsion (a latex containing a polymer other than the chloroprene-based polymer).

[0068] Examples of the polymer emulsion include one or more selected from acrylic emulsions, polyurethane emulsions, styrene / butadiene rubber latexes, acrylonitrile / butadiene rubber latexes, natural rubber latexes, etc., and an acrylic emulsion is preferably contained. The acrylic emulsion can be obtained by copolymerizing (meth)acrylate with a monomer having a functional group, a monomer having a crosslinking group, and / or other copolymerizable monomers as needed.

[0069] In the adhesive composition according to an embodiment of the present invention, with respect to 100 parts by mass of the solid content of the chloroprene-based polymer latex, the content of the polymer emulsion is, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45 parts by mass, and may also be within the range between any two values exemplified herein. One kind of the polymer emulsion can be used alone, or two or more kinds can be used in combination. The adhesive composition according to an embodiment of the present invention can maintain the initial adhesion strength and further improve its storage stability and the texture (hardness) of the adhesive layer by containing a polymer emulsion (especially an acrylic emulsion containing an acrylic polymer).

[0070] The adhesive composition according to an embodiment of the present invention may contain known components, for example, it may contain a tackifier, an acid acceptor, an antioxidant, a filler, a pigment, a colorant, a wetting agent, a defoaming agent, a thickening agent, etc. Examples of the tackifier include phenolic resins, terpene resins, rosin derivative resins, petroleum-based hydrocarbons, etc. In the adhesive composition according to an embodiment of the present invention, with respect to 100 parts by mass of the solid content of the chloroprene-based polymer latex composition, the amount of the tackifier can be 5 parts by mass or less, or less than 1 part by mass. With respect to 100 parts by mass of the solid content of the chloroprene-based polymer latex composition, the amount of the tackifier is, for example, 0, 1, 2, 3, 4, 5 parts by mass, and may also be within the range between any two values exemplified herein. The chloroprene-based polymer latex composition according to an embodiment of the present invention can be adjusted to an appropriate viscosity even when the amount of the tackifier is less than that of the conventional adhesive composition because it has an appropriate viscosity.

[0071] The adhesive composition in an embodiment of the present invention preferably has an initial adhesion strength 1 of 3.0 N / cm measured by the above method 2 and / or an initial adhesion strength 2 of 6.0 N / cm 2 or more.

[0072] The initial adhesion strength 1 is, for example, 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, or within a range between any two of the values exemplified herein.

[0073] The initial adhesion strength 2 is, for example, 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 , or within a range between any two of the values exemplified herein.

[0074] In the case of the adhesive composition according to an embodiment of the present invention, the incidence rate of agglomerates in the mechanical stability test under the conditions of a load of 1.0 kg and a rotation speed of 1000 rpm is preferably 1.00 to 10.00%. The incidence rate of agglomerates in the mechanical stability test of the test adhesive composition under the conditions of a load of 1.0 kg and a rotation speed of 1000 rpm is, for example, 1.00, 2.00, 3.00, 4.00, 5.00, 6.00, 7.00, 8.00, 9.00, 10.00%, or within a range between any two of the values exemplified herein.

[0075] When the incidence rate of agglomerates in the mechanical stability test of the adhesive composition is equal to or higher than the above lower limit, the adhesive composition is moderately emulsified and broken after coating, and a more sufficient initial adhesion strength can be exhibited. In addition, when the incidence rate of agglomerates in the mechanical stability test of the adhesive composition is equal to or higher than the above upper limit, precipitation of the adhesive composition due to the shear force during spraying can be prevented, thereby preventing deterioration of the sprayability. The incidence rate of agglomerates in the mechanical stability test of the adhesive composition can be specifically measured by the method described in the examples. It is considered that by adjusting the manufacturing conditions of the chloroprene-based polymer latex composition, and adjusting the particle size, its distribution, and the tendency of emulsion breakage of the chloroprene-based polymer in the obtained chloroprene-based polymer latex composition, the incidence rate of agglomerates in the mechanical stability test of the adhesive composition can be controlled.

[0076] In the case of the adhesive composition according to an embodiment of the present invention, the viscosity measured with a B-type viscometer at 23°C and 6 rpm is preferably 100 to 5000 mPa·s. The viscosity of the adhesive composition measured with a B-type viscometer at 23°C and 6 rpm is, for example, 100, 200, 300, 400, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000 mPa·s, or within a range between any two of the values exemplified herein.

[0077] By having a viscosity of at least the above lower limit, after spraying the adhesive composition, it is possible to reduce the dripping of droplets adhering to the adherend. In addition, it is possible to avoid the droplets adhering to the adherend from penetrating deep into the adherend, resulting in insufficient formation of the surface adhesive layer and insufficient adhesive strength. By having a viscosity of at most the above upper limit, it is possible to prevent it from being difficult to spray due to low fluidity, suppress a decrease or unevenness in the coating amount, and as a result, prevent a decrease in adhesive strength. The viscosity of the adhesive composition can be specifically measured according to the method described in the examples. It is considered that by adjusting the manufacturing conditions of the chloroprene-based polymer latex composition and adjusting the particle size, its distribution, and the tendency of emulsion breakdown of the chloroprene-based polymer in the obtained chloroprene-based polymer latex composition, the viscosity can be controlled.

[0078] In the adhesive composition according to one embodiment of the present invention, the adhesive is preferably an aqueous adhesive, and more preferably used as a one-component aqueous adhesive. The adhesive composition according to one embodiment of the present invention can preferably be used as a spray-type adhesive, and particularly preferably used as a spray-type adhesive for bonding the following adherends.

[0079] Examples of the adherend to be bonded by the adhesive composition according to one embodiment of the present invention include foams (foams) made of materials such as polyurethane, ethylene-vinyl acetate copolymer, and polyethylene, wood, cloth, and fabric. The adhesive composition according to one 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 is suitable for, for example, the manufacture of furniture including polyurethane foam components.

Examples

[0080] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these.

[0081] <Production of chloroprene-based polymer latex> In an autoclave 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, 4.5 parts by mass of potassium rosin 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-naphthalene sulfonic 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 reached 83% by mass, polymerization was terminated by adding phenothiazine as a polymerization terminator to obtain the latex before distillation. 0.20 part of polyoxyethylene styrenyl phenyl ether (trade name "Noigen EA-137", manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as a nonionic surfactant was added, and the unreacted monomer was removed by vacuum distillation of the latex before distillation to obtain the distilled latex A containing a chloroprene-based polymer (solid content: 55% by mass).

[0082] Using the components and conditions shown in Tables 1 to 2, and otherwise performing the same operations as for latex A, latexes B to R (solid content: 55% by mass) were obtained. In addition, potassium disproportionated rosin manufactured by Arakawa Chemical Industries, Ltd. was used as potassium rosin A.

[0083] [Evaluation of Chloroprene-Based Polymer Latex Composition] [Contents of Conjugated Resin Acid Component and Non-Conjugated Resin Acid Component in Rosin Acid Component] The contents of the conjugated resin acid component and the non-conjugated resin acid component in the above-mentioned potassium rosin A and potassium disproportionated rosin were measured. First, rosin acid was dissolved in an ethanol / toluene azeotropic mixture (ETA solution) specified in JIS K 6229, and hydrochloric acid treatment was performed to obtain a solution (rosin acid: 1.5% by mass). Gas chromatography analysis was carried out using this solution under the following conditions.

[0084] [Conditions for 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

[0085] From the measurement results of gas chromatography, 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, these conjugated resin acid components are obtained. At the same time, the peak areas of dehydroabietic acid components, pimaric acid components, isopimaric acid components, and dihydroabietic acid components, these non-conjugated resin acid components are obtained. The area percentage of the peak area of each component relative to the total peak area is regarded as the content of each component, thereby determining the content of conjugated resin acid components and non-conjugated resin acid components.

[0086] In abietic 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%. 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%. The total area of non-conjugated resin acid components is 46.7%.

[0087] The above disproportionated potassium abietate was also analyzed by gas chromatography. As a result, no abietic acid component, neoabietic acid component, palustric acid component, and levopimaric acid component were detected. The area percentage of non-conjugated resin acid components is 68.8% for dehydroabietic acid component, 0.5 for pimaric acid component, and 21.1% for dihydroabietic acid component. The total area of non-conjugated resin acid components is 90.4%.

[0088] <Content of Conjugated Resin Acid Components in Chloroprene Polymer> 3 g of the solid component of the chloroprene polymer obtained by freeze-drying the above chloroprene polymer latex was cut into squares with a side length of 2 mm to obtain test samples. After putting the test samples into a pear-shaped flask equipped with a condenser, the extract obtained by extracting with the ethanol / toluene azeotropic mixture (ETA solution) specified in JIS K 6229 and treating with hydrochloric acid was subjected to gas chromatography analysis under the same conditions as the analysis of the content of conjugated resin acid components and non-conjugated resin acid components in abietic acid components, and the content of conjugated resin acid components in the chloroprene polymer was calculated. The results are shown in Tables 1 to 2.

[0089] <Content of Polyoxyethylene Styrenylphenyl Ether per 100 Parts by Mass of Chloroprene Polymer> Using a JNM-ECX-400 (400 MHz, FT type) manufactured by JEOL Ltd., a sample solution was measured, which was prepared by dissolving 1.0 mg of the internal standard substance sodium trimethylsilylpropionate d4 (TSP-d4) and approximately 30 mg of polyoxyethylene styrenyl phenyl ether (trade name "Noigen EA-137", manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) in 1.0 mL of heavy water. 1 The 1H-NMR spectrum was obtained. When heavy water (4.65 ppm) was used as the reference substance for chemical shift, a peak area I of -0.50 to 0.50 ppm from TSP-d4 was obtained. TSP and a peak area I of 3.00 to 4.00 ppm from polyoxyethylene styrenyl phenyl ether. 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 signal 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 taken as the ETA extraction rate. Using a JNM-ECX-400 (400 MHz, FT type) manufactured by JEOL Ltd., the 1H-NMR spectrum of a sample solution prepared 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. 1 When heavy water (4.65 ppm) was used as the reference substance for chemical shift, a peak area I of -0.50 to 0.50 ppm from TSP was obtained. TSP and a 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 :Ix / H EA-137 Calculate 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 by the following formula. C(%) = W x (mg) / mass of dry matter (mg) × 100 × ETA extraction rate (%) Calculate the mass parts of polyoxyethylene styrenyl phenyl ether relative to 100 mass parts of the chloroprene-based polymer from the obtained value of C, and obtain the values in Tables 1 to 2.

[0090] <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

[0091] <Toluene-insoluble component> Cut 1 g of the chloroprene-based polymer obtained by freeze-drying the above chloroprene-based polymer latex into 2 mm squares to obtain a test sample. After adding this test sample to a conical flask, dissolve the test sample with 80 g of toluene over 16 hours. Then, after centrifugation, separate the gel component (insoluble matter) using a 200-mesh wire mesh. After that, dry the gel component and measure the mass of the dry matter. When the freeze-dried latex is denoted as A g and the gel component (insoluble matter) 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.

[0092] <Average particle size> Dilute and adjust the above chloroprene-based polymer latex with distilled water to a solid content concentration of 0.01 mass%, and determine the average particle size using ELSZ Series (manufactured by Otsuka Electronics Co., Ltd.). Here, the average particle size of the latex is 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 to 2.

[0093] <Mechanical stability> Using a Maron test apparatus, a shear force of 10 kg load and 1000 rpm rotation speed was applied to 50 g of a chloroprene-based polymer latex composition with a solid component concentration of 55% by mass for 10 minutes, and the amount of coagulum generated at this time was evaluated. After applying the shear force under the above conditions, the coagulum adhering to the rotor part of the Maron test apparatus was collected on a SUS 80-mesh wire net, washed with pure water, dried under reduced pressure, and its mass was measured. The coagulum generation rate was calculated from the measured dry mass of the coagulum according to the following formula, thereby obtaining an index of mechanical stability. The smaller the value of the coagulum generation rate, the more stable it is with respect to the shear force, indicating good mechanical stability. Coagulum generation rate (mechanical stability) (%) = Dry mass of coagulum [g] / Mass of solid component of chloroprene-based polymer latex composition [g] × 100

[0094] <Viscosity> The viscosity of a chloroprene-based polymer latex composition with a solid component concentration of 55% by mass was measured at 23 °C and 6 rpm using a B-type viscometer. The viscosity was measured under the following conditions. Measuring equipment: "VISCOMETER TVB-20L" manufactured by Toki Sangyo Co., Ltd. Spindle rotor: 1M (cylindrical with a radius of 19 mm and a thickness of 65 mm) Rotation speed: 6 rpm

[0095] [Evaluation of adhesive composition] (Preparation of adhesive composition) Relative to 182 parts by mass of the above-obtained chloroprene-based polymer latex (100 parts by mass of solid component), 25 parts by mass of an acrylic emulsion (trade name "Acronal Proof 1299", BASF with a solid component of 55% by mass) and 11 parts by mass of glycine as a pH regulator were added, and an aqueous adhesive (adhesive composition) was prepared by stirring with a San-ichi motor. In addition, in Example 14 and Reference Example 1, the formulation of the adhesive composition is as described in Table 2. The initial adhesive strength of the aqueous adhesive (adhesive composition) obtained using sodium polyacrylate (trade name "Aron A-20L", manufactured by Toagosei Co., Ltd.) as a tackifier was measured by the following method, and the measurement results are shown in Tables 1 to 2.

[0096] <Initial adhesive strength> Two polyurethane foams with a density of 30 kg / m 3 were used as adherends, and the adhesive composition was applied at 70 g / m 2Spray it on each adherend. After coating, stack the bonding surfaces of the polyurethane foams with each other while the adhesive composition is in an undried state, 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 bonding strength 1) or place it (initial bonding strength 2) for 15 minutes, 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 bonding strength.

[0097] <Sprayability> Spray the above aqueous adhesive (adhesive composition) on the adherend (polyurethane foam), and evaluate the sprayability (blocking degree and coatability of the adhesive composition on the adherend) according to the following evaluation criteria. (Blocking degree) ○: No blockage, can be sprayed well △: Slightly blocked but can be sprayed ×: Unable to spray due to blockage (Coatability of the adhesive composition on the adherend) ○: No infiltration or dripping of the adhesive composition into the adherend is observed △: Slight infiltration or dripping of the adhesive composition into the adherend is observed ×: Infiltration or dripping of the adhesive composition into the adherend is observed -: Unable to spray due to blockage, unable to evaluate the coatability.

[0098] <Mechanical stability> Using a Maron test device, apply a shear force of 1.0 kg and a rotational speed of 1000 rpm to 50 g of the adhesive composition for 2 minutes, and evaluate the amount of coagulum generated at this time. After applying the shear force under the above conditions, collect the coagulum attached to the rotor part of the Maron test device on a SUS 80-mesh wire mesh, wash it with pure water, dry it under reduced pressure, and measure its mass. Calculate the coagulum incidence rate according to the following formula from the measured dry mass of the coagulum, and use it as an index of mechanical stability. The smaller the value of the coagulum incidence rate, the more stable it is with respect to the shear force, indicating good mechanical stability. Coagulum incidence rate (mechanical stability) (%) = dry mass of coagulum [g] / solid component mass of the chloroprene-based polymer latex composition [g] × 100

[0099] <Viscosity> The viscosity of the adhesive composition was measured at 23°C and 6 rpm using a B-type viscometer. The viscosity was measured under the following conditions. In addition, since the viscosity of the adhesive composition tends to be higher than that of the chloroprene-based polymer latex composition, a spindle rotor different from that used for measuring the viscosity of the chloroprene-based polymer latex composition was used. Measuring equipment: "VISCOMETER TVB-20L" manufactured by Toki Sangyo Co., Ltd. Spindle rotor: 2M (a disk-shaped rotor with a radius of 19 mm and a thickness of 7 mm) Rotation speed: 6 rpm

[0100] [Table 1]

[0101] [Table 2]

Claims

1. A chloroprene-based polymer latex composition comprising a chloroprene-based polymer, The chloroprene-based polymer latex composition is adjusted to a solid content concentration of 55% by mass to obtain a test chloroprene-based polymer latex composition, In a mechanical stability test under the conditions of a load of 10 kg and a rotation speed of 1000 rpm, the coagulum incidence rate of the test chloroprene-based polymer latex composition is 0.01 to 1.00%, At 23°C and 6 rpm, the viscosity of the test chloroprene-based polymer latex composition measured with a B-type viscometer is 22 to 100 mPa·s.

2. The chloroprene polymer latex composition according to claim 1, wherein, Relative to 100 parts by mass of the chloroprene-based polymer, the chloroprene-based polymer latex composition contains 0.5 to 3.5 parts by mass of a conjugated resin acid.

3. The chloroprene-based polymer latex composition according to claim 1 or 2, wherein the toluene-insoluble component of the chloroprene-based polymer is 30% by mass or less.

4. The chloroprene polymer latex composition according to claim 1 or 2, wherein Relative to 100 parts by mass of the chloroprene-based polymer, the chloroprene-based polymer latex composition contains 0.40 parts by mass or less of a nonionic surfactant.

5. The chloroprene-based polymer latex composition according to claim 1 or 2, The chloroprene-based polymer latex composition, an acrylic latex containing an acrylic polymer, and a pH adjuster are mixed to prepare a test adhesive composition containing 25 parts by mass of the acrylic polymer and 11 parts by mass of the pH adjuster relative to 100 parts by mass of the chloroprene-based polymer, In a mechanical stability test under the conditions of a load of 1.0 kg and a rotation speed of 1000 rpm, the coagulum incidence rate of the test adhesive composition is 1.0 to 10.0%, At 23°C and 6 rpm, the viscosity of the test adhesive composition measured with a B-type viscometer is 100 to 5000 mPa·s.

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

7. The adhesive composition according to claim 6, wherein in a mechanical stability test under the conditions of a load of 1.0 kg and a rotation speed of 1000 rpm, the coagulum incidence rate is 1.0 to 10.0%, At 23°C and 6 rpm, the viscosity measured with a B-type viscometer is 100 to 5000 mPa·s.

8. The adhesive composition according to claim 6, which is an adhesive composition for polyurethane foam.

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