Chloroprene polymer composition, method for producing chloroprene polymer composition, and adhesive composition

Abstract

The present invention provides: a chloroprene polymer composition which is not susceptible to layer separation and coloring when mixed with a solvent, and which enables the preparation of an adhesive composition that is excellent in terms of storage stability; and a method for producing a chloroprene polymer composition. The present invention specifically provides a chloroprene polymer composition which contains a chloroprene polymer, wherein: the chloroprene polymer composition has a moisture content of 10 mass% or less; and the content C of dehydroabietic acid, which is present in the form of a dehydroabietic acid salt, with respect to 100 parts by mass of the chloroprene polymer composition is 0.075-1.600 parts by mass as measured by a specific measurement method.

Description

Chloroprene polymer composition, method for producing chloroprene polymer composition, and adhesive composition

[0001] The present invention relates to a chloroprene polymer composition, a method for producing a chloroprene polymer composition, and an adhesive composition.

[0002] Chloroprene polymers are substances with excellent heat resistance, weather resistance, ozone resistance, chemical resistance, flame retardancy (self-extinguishing properties), etc., and have many excellent properties compared to natural rubber, other synthetic resins, etc. Chloroprene polymers, which have such well-balanced physical properties overall, are used in a variety of applications, one example of which is as an adhesive.

[0003] For example, Patent Document 1 discloses an adhesive composition obtained by dissolving, in an organic solvent, an unmodified chloroprene polymer A obtained by polymerizing chloroprene alone or copolymerizing two or more monomers including chloroprene, and a sulfur-modified chloroprene polymer B obtained by polymerizing chloroprene alone or copolymerizing two or more monomers including chloroprene in the presence of sulfur.

[0004] JP 2012-111862 A

[0005] However, conventional chloroprene polymer compositions containing chloroprene polymers may suffer from phase separation or coloration when mixed with a solvent, and there is also room for improvement in the storage stability of prepared adhesive compositions.

[0006] The present invention has been made in view of the above circumstances, and provides a chloroprene polymer composition that is resistant to layer separation and coloration when mixed with a solvent and that exhibits excellent storage stability when prepared as an adhesive composition; a method for producing a chloroprene polymer composition; and an adhesive composition.

[0007] According to the present invention, there is provided a chloroprene polymer composition containing a chloroprene polymer, wherein the chloroprene polymer composition has a water content of 10% by mass or less, and a content C of dehydroabietic acid present in the form of a dehydroabietic acid salt of 0.075 to 1.600 parts by mass relative to 100 parts by mass of the chloroprene polymer composition, as measured by the following measurement method. <Measurement Method> 1. Vacuum-dry 3 g±0.03 g of the chloroprene polymer composition to obtain a dried chloroprene polymer composition having a water content of 0.5% by mass or less. 2. The dried chloroprene polymer composition is shredded into cubes measuring 2 to 3 mm on a side and placed in an eggplant flask. 35 mL of ETA (ethanol:toluene = 70:30 vol%) as specified in JIS K 6229 is added, and the resulting extract is extracted by heating at 90°C for 1 hour. The resulting extract is then placed in a 100 mL volumetric flask. 3. 35 mL of ETA is added again to the recovery flask containing the dried chloroprene polymer composition, and the mixture is heated and extracted at 90°C for 1 hour. The resulting extract is then added to the 100 mL volumetric flask. 4. When the extract in the 100 mL volumetric flask reaches 23°C, the extract is adjusted to 100 mL with ETA to obtain a solution for analysis before acid treatment. 5. 50 mL of the solution for analysis before acid treatment is analyzed by gas chromatography to quantify the amount of dehydroabietic acid, and the pre-acid treatment dehydroabietic acid content A per 100 parts by mass of the chloroprene polymer composition is calculated. The amount of dehydroabietic acid is quantified based on a calibration curve obtained by measuring a dehydroabietic acid ETA solution with a known dehydroabietic acid content. 6. 50 mL of the pre-acid treatment analysis solution is dried, a small amount of ETA is added, and the solution is dissolved by ultrasonic vibration. 1 mol / L hydrochloric acid is added to adjust the pH to 1, and the solution is dried, dissolved in methanol, and the volume is adjusted to 50 mL to obtain a post-acid treatment analysis solution. 7. The post-acid treatment analysis solution is analyzed by gas chromatography to quantify the dehydroabietic acid, and the post-acid treatment dehydroabietic acid content B per 100 parts by mass of the chloroprene polymer composition is calculated.The amount of dehydroabietic acid is determined based on a calibration curve obtained by measuring a methanol solution of dehydroabietic acid with a known content of dehydroabietic acid. 8 The content C of dehydroabietic acid present in the form of a dehydroabietic acid salt is calculated by subtracting the content A of dehydroabietic acid before acid treatment from the content B of dehydroabietic acid after acid treatment.

[0008] As a result of extensive investigations, the present inventors have found that, in a chloroprene polymer composition having a water content of not more than a certain level after precipitation, by highly adjusting the content C of dehydroabietic acid present in the form of a dehydroabietic acid salt, a chloroprene polymer composition is obtained which is less likely to undergo phase separation or coloration when mixed with a solvent and which has excellent storage stability when used to prepare an adhesive composition, thereby completing the present invention.

[0009] Various embodiments of the present invention are exemplified below. The embodiments shown below can be combined with each other. [1] A chloroprene polymer composition containing a chloroprene polymer, wherein the chloroprene polymer composition has a water content of 10% by mass or less, and a content C of dehydroabietic acid present in the form of a dehydroabietic acid salt is 0.075 to 1.600 parts by mass relative to 100 parts by mass of the chloroprene polymer composition, as measured by the following measurement method. <Measurement Method> 1. 3 g±0.03 g of the chloroprene polymer composition is vacuum-dried to obtain a dried chloroprene polymer composition having a water content of 0.5% by mass or less. 2. The dried chloroprene polymer composition is shredded into cubes measuring 2 to 3 mm on a side and placed in a recovery flask. 35 mL of ETA (ethanol:toluene = 70:30 vol.%) as specified in JIS K 6229 is added, and extraction is carried out by heating at 90°C for 1 hour. The resulting extract is then placed in a 100 mL volumetric flask. 3. 35 mL of ETA is again added to the recovery flask containing the dried chloroprene polymer composition, and extraction is carried out by heating at 90°C for 1 hour. The resulting extract is then placed in the 100 mL volumetric flask. 4. When the extract in the 100 mL volumetric flask reaches 23°C, the extract is adjusted to 100 mL with ETA to obtain a solution for analysis before acid treatment. 5. 50 mL of the pre-acid treatment analytical solution is analyzed by gas chromatography to quantify the amount of dehydroabietic acid, and the pre-acid treatment dehydroabietic acid content A per 100 parts by mass of the chloroprene polymer composition is calculated. The dehydroabietic acid content is quantified based on a calibration curve obtained by measuring a dehydroabietic acid ETA solution with a known dehydroabietic acid content. 6. 50 mL of the pre-acid treatment analytical solution is dried, a small amount of ETA is added, and the solution is dissolved by ultrasonic vibration. 1 mol / L hydrochloric acid is added to adjust the pH to 1, followed by drying, dissolving in methanol, and the volume is adjusted to 50 mL to obtain a post-acid treatment analytical solution. 7. The post-acid treatment analytical solution is analyzed by gas chromatography to quantify the amount of dehydroabietic acid, and the post-acid treatment dehydroabietic acid content B per 100 parts by mass of the chloroprene polymer composition is calculated.The amount of dehydroabietic acid is determined based on a calibration curve obtained by measuring a methanol solution of dehydroabietic acid with a known dehydroabietic acid content. 8. The content C of dehydroabietic acid present in the form of a dehydroabietic acid salt is calculated by subtracting the content A of dehydroabietic acid before acid treatment from the content B of dehydroabietic acid after acid treatment. [2] The chloroprene polymer composition according to [1], which contains at least one typical element selected from the third and fourth periodic elements, and in which the content of the typical element is 0.005 to 0.100 parts by mass per 100 parts by mass of the chloroprene polymer composition. [3] The chloroprene polymer composition according to [2], wherein the typical element comprises at least one selected from calcium, magnesium, and aluminum. [4] The chloroprene polymer composition according to any one of [1] to [3], which is for use in an adhesive containing an organic solvent. [5] A method for producing a chloroprene polymer composition, comprising: a coagulant composition adding and mixing step; and a washing step; wherein in the coagulant composition adding and mixing step, a coagulant composition is added to and mixed with a chloroprene polymer latex containing a chloroprene polymer and water, thereby precipitating a chloroprene polymer composition containing the chloroprene polymer; the coagulant composition contains at least one typical element selected from the third and fourth period elements and an acid; the coagulant composition has a pH of 0.7 to 2.5; and the coagulant composition is added in an amount of 50 to 200 parts by mass per 100 parts by mass of the chloroprene polymer latex; and in the washing step, the chloroprene polymer composition is washed with water to remove at least a portion of the coagulant composition adhering to the chloroprene polymer composition.[6] A method for producing a chloroprene polymer composition, comprising: a first coagulant composition adding and mixing step; a second coagulant composition adding and mixing step; and a washing step. In the first coagulant composition adding and mixing step, the first coagulant composition is added to and mixed with a chloroprene polymer latex containing a chloroprene polymer and water to obtain a first coagulant composition added mixed solution, the first coagulant composition contains an acid, the first coagulant composition has a pH of 0.7 to 4.0, and the amount of the first coagulant composition added is 25 to 100 parts by mass with respect to 100 parts by mass of the chloroprene polymer latex. a second coagulant composition is added to the mixture after the addition of the first coagulant composition and mixed therewith to precipitate a chloroprene polymer composition containing the chloroprene polymer, the second coagulant composition containing at least one typical element selected from the third and fourth period elements, the amount of the second coagulant composition added being 25 to 100 parts by mass per 100 parts by mass of the chloroprene polymer latex, and the washing step involves washing the chloroprene polymer composition with water to remove at least a portion of the first coagulant composition and the second coagulant composition adhering to the chloroprene polymer composition. [7] The method for producing a chloroprene polymer composition according to [5] or [6], wherein the acid comprises at least one acid selected from acetic acid, hydrochloric acid, sulfuric acid, and nitric acid. [8] The method for producing a chloroprene polymer composition according to any of [5] to [7], wherein at least a portion of the steps is carried out in an extruder. [9] An adhesive composition comprising the chloroprene polymer composition according to any of [1] to [4].

[0010] According to the present invention, it is possible to obtain a chloroprene polymer composition that is resistant to phase separation and coloration when mixed with a solvent and that has excellent storage stability when prepared as an adhesive composition. The present invention also provides a method for producing the chloroprene polymer composition. The present invention also provides an adhesive composition that has excellent resistance to phase separation, little coloration, and excellent storage stability.

[0011] The present invention will be described in detail below by illustrating embodiments of the present invention. The present invention is not limited by these descriptions. The features of the embodiments of the present invention described below can be combined with each other. Furthermore, each feature can be an invention independently.

[0012] The chloroprene polymer composition according to the present invention contains a chloroprene polymer. The chloroprene polymer composition according to the present invention has a water content of 10% by mass or less, and a content C of dehydroabietic acid present in the form of a dehydroabietic acid salt of 0.075 to 1.600 parts by mass relative to 100 parts by mass of the chloroprene polymer composition, as measured by a specific measurement method.

[0013] 1.1 Chloroprene Polymer The chloroprene polymer composition according to the present invention contains a chloroprene polymer. The chloroprene polymer according to the present invention may be a homopolymer of 2-chloro-1,3-butadiene (hereinafter referred to as chloroprene) or a copolymer of a chloroprene monomer and another monomer copolymerizable therewith.

[0014] The chloroprene polymer according to one embodiment of the present invention may be a copolymer of chloroprene and another monomer copolymerizable with chloroprene. The other monomer is not particularly limited as long as it is copolymerizable with the chloroprene monomer, and examples thereof include (meth)acrylic acid esters (methyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc.), hydroxyalkyl (meth)acrylates (2-hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, etc.), 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, butadiene, isoprene, unsaturated nitriles, ethylene, styrene, sulfur, etc.

[0015] From the viewpoint of maintaining the properties derived from chloroprene, the chloroprene polymer according to one embodiment of the present invention preferably contains 70% by mass or more, and more preferably 90% by mass or more, of monomer units derived from chloroprene monomers, based on 100% by mass of the chloroprene polymer, although this is not particularly limited. The content of the monomer units derived from chloroprene monomers may be, for example, 70, 75, 80, 85, 90, 95, or 100% by mass, and may be within a range between any two of the values ​​exemplified here. When the content of the monomer units derived from chloroprene monomers in the chloroprene polymer is equal to or greater than the above lower limit, the crystallinity of the chloroprene polymer is increased, and the adhesive strength of an adhesive composition containing the chloroprene polymer after long-term use is further improved.

[0016] 1.2 Water Content The chloroprene polymer composition according to the present invention has a water content of 10% by mass or less. A production method will be described later, but the chloroprene polymer composition according to one embodiment of the present invention can be obtained by adding a coagulant composition to a chloroprene polymer latex containing a chloroprene polymer, precipitating the chloroprene polymer composition containing the chloroprene polymer, and removing the water. The chloroprene polymer composition according to one embodiment of the present invention can be a composition containing a chloroprene polymer (rubber) precipitated (coagulated) from the chloroprene polymer latex using the coagulant composition.

[0017] The chloroprene polymer composition is allowed to contain 10.0% by mass or less of water relative to 100% by mass of the chloroprene polymer composition, and the water content may be, for example, 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, or 10.0% by mass, or may be within a range between any two of the values ​​exemplified here. The solids concentration of the chloroprene polymer composition is 90.0% by mass or more, for example, 90.0, 90.5, 91.0, 91.5, 92.0, 92.5, 93.0, 93.5, 94.0, 94.5, 95.0, 95.5, 96.0, 96.5, 97.0, 97.5, 98.0, 98.5, 99.0, 99.5, or 100.0% by mass, and may be within a range between any two of the values ​​exemplified here.

[0018] 1.3 Content C of dehydroabietic acid present in the form of dehydroabietic acid salt In the chloroprene polymer composition according to the present invention, the content C of dehydroabietic acid present in the form of dehydroabietic acid salt relative to 100 parts by mass of the chloroprene polymer composition, as measured by a specific measurement method, is 0.075 to 1.600 parts by mass, and preferably 0.075 parts by mass or more and less than 0.750 parts by mass. The content C of dehydroabietic acid present in the form of dehydroabietic acid salt may be, for example, 0.075, 0.100, 0.125, 0.150, 0.175, 0.200, 0.225, 0.250, 0.275, 0.300, 0.325, 0.350, 0.375, 0.400, 0.425, 0.450, 0.475, 0.500, 0.525, 0.550, 0.575, 0.600, 0.625, 0.650, 0.675, 0.700, 0.725, 0.750, 0.775, 0.800, 0. 825, 0.850, 0.875, 0.900, 0.925, 0.950, 0.975, 1.000, 1.025, 1.050, 1.075, 1.100, 1.125, 1.150, 1.175, 1.200, 1.225, 1.250, 1.275, 1.300, 1.325, 1.350, 1.375, 1.400, 1.425, 1.450, 1.475, 1.500, 1.525, 1.550, 1.575, 1.600 parts by mass, and may be within a range between any two of the numerical values ​​exemplified here.

[0019] In the present invention, the amount of dehydroabietic acid measured by the following measurement method is defined as the "content C of dehydroabietic acid present in the form of a dehydroabietic acid salt." <Measurement Method> 1. 3 g±0.03 g of the chloroprene polymer composition is vacuum-dried to obtain a dried chloroprene polymer composition having a moisture content of 0.5 mass% or less. 2. The dried chloroprene polymer composition is shredded into cubes (polyhedrons, for example, hexahedrons, specifically cubes, rectangular parallelepipeds, etc.) with sides of 2 to 3 mm and placed in an eggplant flask. 35 mL of ETA (ethanol:toluene = 70:30 vol%) specified in JIS K 6229 is added, and extraction is performed by heating at 90°C for 1 hour. The obtained extract is then placed in a 100 mL volumetric flask. 3. 35 mL of ETA is added again to the recovery flask containing the dried chloroprene polymer composition, and the mixture is heated and extracted at 90°C for 1 hour. The resulting extract is then added to the 100 mL volumetric flask. 4. When the extract in the 100 mL volumetric flask reaches 23°C, the extract is adjusted to 100 mL with ETA to obtain a solution for analysis before acid treatment. 5. 50 mL of the solution for analysis before acid treatment is analyzed by gas chromatography to quantify the amount of dehydroabietic acid, and the pre-acid treatment dehydroabietic acid content A per 100 parts by mass of the chloroprene polymer composition is calculated. The amount of dehydroabietic acid is quantified based on a calibration curve obtained by measuring a dehydroabietic acid ETA solution with a known dehydroabietic acid content. 6. 50 mL of the pre-acid treatment analytical solution is dried, a small amount of ETA is added, and the solution is dissolved by ultrasonic vibration. 1 mol / L hydrochloric acid is added to adjust the pH to 1, followed by drying, dissolving in methanol, and the volume is adjusted to 50 mL to obtain a post-acid treatment analytical solution. 7. The post-acid treatment analytical solution is analyzed by gas chromatography to quantify the amount of dehydroabietic acid, and the post-acid treatment dehydroabietic acid content B per 100 parts by mass of the chloroprene polymer composition is calculated. The amount of dehydroabietic acid is quantified based on a calibration curve obtained by measuring a dehydroabietic acid methanol solution with a known dehydroabietic acid content.8. The content C of dehydroabietic acid present in the form of dehydroabietic acid salt is calculated by subtracting the content A of dehydroabietic acid before acid treatment from the content B of dehydroabietic acid after acid treatment.

[0020] According to the present invention, by setting the "content C of dehydroabietic acid present in the form of dehydroabietic acid salt" measured by the above-mentioned measurement method within the above-mentioned numerical range, a chloroprene polymer composition is obtained that is less likely to undergo phase separation and coloration when mixed with a solvent, and that has excellent storage stability when an adhesive composition is prepared. In particular, by setting the content C of dehydroabietic acid present in the form of dehydroabietic acid salt to be equal to or greater than the above-mentioned lower limit, a chloroprene polymer composition is obtained that is less likely to undergo coloration when mixed with a solvent. Furthermore, by setting the content C of dehydroabietic acid present in the form of dehydroabietic acid salt to be equal to or less than the above-mentioned upper limit, a chloroprene polymer composition is obtained that is less likely to undergo phase separation when mixed with a solvent, and that has excellent storage stability when an adhesive composition is prepared. Furthermore, turbidity is less likely to occur when mixed with a solvent. The mechanism behind this is not clear, but is presumed to be as follows. Note that the following presumed mechanism does not limit the present invention.

[0021] The chloroprene polymer according to the present invention can be obtained by a production method including a polymerization step of emulsion-polymerizing raw material monomers containing chloroprene and, if necessary, other monomers using an emulsifier containing rosin acid. Dehydroabietic acid is one of the main components of rosin acid. Rosin acid salts are available in water-soluble and water-insoluble forms. For example, alkali metal salts such as sodium and potassium are readily soluble in water, while salts of third- and fourth-period elements such as calcium, magnesium, and aluminum are poorly soluble in water. Furthermore, the coagulant composition used in the coagulant composition addition and mixing step to precipitate a chloroprene polymer composition containing a chloroprene polymer may contain third- and fourth-period elements such as calcium, magnesium, and aluminum. Therefore, the chloroprene polymer composition obtained by the production method including the coagulant composition addition and mixing step may contain poorly water-soluble rosin acid salts of third- and fourth-period elements. The "content C of dehydroabietic acid present in the form of a dehydroabietic acid salt" measured by the above-mentioned measurement method is considered to be an index of the amount of a rosin acid salt that is poorly soluble in water contained in the chloroprene polymer composition.

[0022] The "content C of dehydroabietic acid present in the form of a dehydroabietic acid salt" according to the present invention is calculated by adding a solvent to a chloroprene polymer composition to obtain an extract containing a component containing rosin acid, and then calculating the difference between the analysis result of the amount of dehydroabietic acid in a pre-acid-treatment analytical solution containing the extract (dehydroabietic acid content A before acid treatment) and the analysis result of the post-acid-treatment analytical solution obtained by treating the extract with acid (dehydroabietic acid content B after acid treatment). Here, the dehydroabietic acid content A before acid treatment is considered to correspond to rosin acid that does not contribute to the formation of a slightly water-soluble salt. Furthermore, after acid treatment, resinate anions (anions of rosin acid) that contributed to the formation of a slightly water-soluble salt are converted back to rosin acid. Therefore, the dehydroabietic acid content B after acid treatment is considered to correspond to the sum of rosin acid that did not contribute to the formation of a slightly water-soluble salt and rosin acid that contributed to the formation of a slightly water-soluble salt. Therefore, it is presumed that the content C of dehydroabietic acid present in the form of a dehydroabietic acid salt, particularly the content C of dehydroabietic acid present in the form of a salt of a representative element of the third and fourth periods such as calcium, magnesium, and aluminum, can be calculated by subtracting the content A of dehydroabietic acid before acid treatment from the content B of dehydroabietic acid after acid treatment.

[0023] In the present invention, by specifying the upper limit of the content C of dehydroabietic acid present in the form of dehydroabietic acid salt, the content of the salt that is poorly soluble in water in the chloroprene polymer composition is reduced to a certain level or less, which is presumably able to prevent phase separation when mixed with an organic solvent and deterioration of storage stability when an adhesive composition is prepared. Furthermore, a chloroprene polymer composition prepared by specifying the lower limit of the content C of dehydroabietic acid present in the form of dehydroabietic acid salt and adjusting the content of the salt that is poorly soluble in water in the chloroprene polymer composition to a certain level or more is less likely to discolor when mixed with a solvent. Although the mechanism is unclear, discoloration may be due to the structure of the chloroprene polymer, and it is thought that specifying the lower limit of the content C of dehydroabietic acid present in the form of dehydroabietic acid salt indirectly controls the structure of the chloroprene polymer and reduces discoloration.

[0024] The content C of dehydroabietic acid present in the form of a dehydroabietic acid salt can be controlled by adjusting the production method for the chloroprene polymer composition to a high degree. For example, the content C can be controlled by adjusting the composition, amount, pH, and number of additions of the coagulant composition in the coagulant composition adding and mixing step for precipitating the chloroprene polymer composition containing a chloroprene polymer, as well as the presence or absence of a water-washing step, the amount of water used, and the number of water-washing steps.

[0025] 1.4 Period 3 and Period 4 Typical Elements The chloroprene polymer composition according to one embodiment of the present invention may contain at least one of period 3 and period 4 typical elements, and the content of the period 3 and period 4 typical elements may be 0.005 to 0.100 parts by mass per 100 parts by mass of the chloroprene polymer composition. The content of the period 3 and period 4 typical elements is preferably 0.005 part by mass or more and less than 0.100 part by mass. The contents of the third and fourth period typical elements are, for example, 0.005, 0.010, 0.015, 0.020, 0.025, 0.030, 0.035, 0.040, 0.045, 0.050, 0.055, 0.060, 0.065, 0.070, 0.075, 0.080, 0.085, 0.090, 0.095, and 0.100 parts by mass, and may be within a range between any two of the numerical values ​​exemplified here.

[0026] A chloroprene polymer composition in which the contents of the period 3 and period 4 typical elements are adjusted to be equal to or greater than the above lower limits is less likely to be discolored when mixed with a solvent. Furthermore, by adjusting the contents of the period 3 and period 4 typical elements to be equal to or less than the above upper limits, the amount of salts that are poorly soluble in solvents can be kept below a certain level, making it less likely to cause layer separation or turbidity when mixed with a solvent, and resulting in a chloroprene polymer composition that has excellent storage stability when used as an adhesive composition.

[0027] In the present invention, the "content of the third and fourth period typical elements per 100 parts by mass of the chloroprene polymer composition" means the content of the third and fourth period typical elements measured by an inductively coupled plasma optical emission spectrometer (ICP-OES) based on the method described in the Examples. The third and fourth period typical elements contained in the chloroprene polymer composition may include the third and fourth period typical elements present as salts and the third and fourth period typical elements present as ions.

[0028] The typical elements of periods 3 and 4 may include at least one selected from calcium, magnesium, and aluminum, and preferably include calcium. The typical elements of periods 3 and 4 may be derived from a coagulant composition for precipitating a chloroprene polymer (composition) from a chloroprene polymer latex.

[0029] The contents of the third and fourth periodic typical elements can be controlled by adjusting the production method for the chloroprene polymer composition to a high degree. For example, the contents can be controlled by adjusting the composition, amount, pH, and number of additions of the coagulant composition in the coagulant composition adding and mixing step for precipitating a chloroprene polymer composition containing a chloroprene polymer, as well as the presence or absence of a water washing step, the amount of water used, and the number of water washings.

[0030] 1.5 Other Components The chloroprene polymer composition according to one embodiment of the present invention may contain trace amounts of other components, such as chemicals used in the production of the chloroprene polymer latex. Examples of other components include monomers such as chloroprene monomers, dispersants other than rosin acid, emulsifiers, polymerization initiators, chain transfer agents, polymerization inhibitors, polymerization terminators, and antifoaming agents. The chloroprene polymer composition may have a chloroprene polymer content of, for example, 80, 85, 90, 95, or 100% by mass relative to 100% by mass of the chloroprene polymer composition, and may be within a range between any two of the values ​​exemplified here.

[0031] 1.6 Properties of Chloroprene Polymer Composition When the chloroprene polymer composition according to one embodiment of the present invention is vacuum-dried to a moisture content of 0.1% by mass or less and then dissolved in toluene to prepare a 10% by mass toluene solution of the chloroprene polymer composition, it is preferable that the toluene solution has the following properties:

[0032] When a 10% by mass toluene solution of the chloroprene polymer composition is placed in a clear 225 mL glass bottle and visually observed, it is preferred that no turbidity is observed. It is also preferred that the 10% by mass toluene solution is colorless, and no yellow-green color is observed. It is also preferred that a 10% toluene solution of the chloroprene polymer composition is placed in a clear 225 mL glass bottle and left to stand at 23°C for 5 days, after which no layer separation occurs, and specifically, it is preferred that no hazy sedimentation is observed. The "hazy" is a component unnecessary for toluene and water, and is thought to include a resin acid salt, for example, calcium dehydroabietic acid.

[0033] When an adhesive composition is prepared by adding 2 parts by mass of BHT (dibutylhydroxytoluene), 6 parts by mass of MgO (Kyowamag 150, manufactured by Kyowa Chemical Industry Co., Ltd.), 1 part by mass of ZnO (zinc oxide type 2, manufactured by Sakai Chemical Industry Co., Ltd.), and 50 parts by mass of an alkylphenol resin (Tamanol 526, manufactured by Arakawa Chemical Industries Co., Ltd.) to 100 parts by mass of the chloroprene polymer composition according to one embodiment of the present invention, and further adding a solvent of cyclohexane:methyl ethyl ketone=1:1 (mass ratio) so as to have a solution viscosity of 4000±400 mPa s, the adhesive composition preferably shows no layer separation even after 2 days, more preferably shows no layer separation even after 4 days, and even more preferably shows no layer separation even after 7 days.

[0034] 1.7 Applications The chloroprene polymer composition according to one embodiment of the present invention is resistant to phase separation and coloration when mixed with a solvent, and exhibits excellent storage stability when prepared as an adhesive composition. Furthermore, the chloroprene polymer composition according to one embodiment of the present invention does not become cloudy when mixed with a solvent. Therefore, the chloroprene polymer composition according to one embodiment of the present invention is suitable for applications in which it is mixed with an organic solvent, and can be used, for example, as an adhesive containing an organic solvent.

[0035] 2. Method for Producing Chloroprene Polymer Composition The method for producing a chloroprene polymer composition according to one embodiment of the present invention is not particularly limited, but may include a coagulant composition adding and mixing step and a washing step. Hereinafter, as an example, the production methods according to the first embodiment and the second embodiment will be described.

[0036] 2.1 Method for Producing Chloroprene Polymer Composition According to a First Embodiment The method for producing a chloroprene polymer composition according to a first embodiment of the present invention includes a coagulant composition adding and mixing step, and a washing step. In the coagulant composition adding and mixing step, a coagulant composition is added to and mixed with a chloroprene polymer latex containing a chloroprene polymer and water to precipitate a chloroprene polymer composition containing the chloroprene polymer. The coagulant composition contains at least one typical element selected from the third and fourth period elements and an acid, and the coagulant composition has a pH of 0.7 to 2.5 and is added in an amount of 50 to 200 parts by mass per 100 parts by mass of the chloroprene polymer latex. In the washing step, the chloroprene polymer composition is washed with water to remove at least a portion of the coagulant composition adhering to the chloroprene polymer composition. The production method according to the first embodiment will now be described.

[0037] 2.1.1 Emulsion Polymerization Step The method for producing a chloroprene polymer composition can include an emulsion polymerization step prior to the coagulant composition addition and mixing step and the washing step. In the emulsion polymerization step, raw material monomers including a chloroprene monomer or a chloroprene monomer and other monomers copolymerizable therewith are emulsion-polymerized using an emulsifier, a dispersant, a polymerization initiator, a chain transfer agent, etc., as appropriate. When the target polymerization rate is reached, a polymerization terminator is added to obtain a chloroprene polymer latex. Furthermore, unreacted monomers can be removed from the chloroprene polymer latex obtained in this manner by a steam flash method, a concentration method, etc.

[0038] <Emulsifiers and Dispersants> Examples of emulsifiers that can be used include known anionic, nonionic, and cationic emulsifiers used in the polymerization of chloroprene polymers. Anionic emulsifiers include carboxylic acid, sulfonic acid, and sulfate ester emulsifiers, such as higher fatty acid salts, alkenyl succinates, alkali metal salts of rosin acid, alkyl sulfonates having 8 to 20 carbon atoms, alkylaryl sulfates, and condensates of sodium naphthalene sulfonate and formaldehyde. Nonionic emulsifiers include polyvinyl alcohol or copolymers thereof (e.g., copolymers with acrylamide), polyvinyl ether or copolymers thereof (e.g., copolymers with maleic acid), polyvinylpyrrolidone or copolymers thereof (e.g., copolymers with vinyl acetate), chemically modified versions of these (co)polymers, and cellulose derivatives (hydroxyethyl cellulose). Cationic emulsifiers include aliphatic amine salts and aliphatic quaternary ammonium salts, such as octadecyltrimethylammonium chloride, dodecyltrimethylammonium chloride, and dilauryldimethylammonium chloride. Among these, in this embodiment, the emulsifier preferably contains rosin acid or an alkali metal salt of rosin acid. These may be used alone or in combination of two or more. The amount of emulsifier may be 2.0 to 7.5 parts by mass per 100 parts by mass of the monomer.

[0039] <pH Adjuster> The raw materials added to the polymerization system at the start of polymerization may contain a pH adjuster. Examples of pH adjusters include potassium pyrosulfite, potassium sulfite, potassium hydrogensulfite, potassium phosphate, potassium hydrogenphosphate, sodium pyrosulfite, sodium sulfite, sodium hydrogensulfite, sodium phosphate, sodium hydrogenphosphate, potassium hydroxide, and sodium hydroxide. The pH adjuster may be used alone or in combination with two or more of these. Among these pH adjusters, potassium hydroxide and sodium hydroxide are preferred because they are highly effective in increasing the pH value. The amount of pH adjuster added may be 0.01 to 2.0 parts by mass per 100 parts by mass of monomer.

[0040] <Polymerization initiator> The raw materials added to the polymerization system at the start of polymerization may contain a polymerization initiator. As the polymerization initiator, potassium persulfate, benzoyl peroxide, ammonium persulfate, hydrogen peroxide, etc., which are used in ordinary radical polymerization, may be used. The amount of the polymerization initiator added may be 0.001 to 1 part by mass per 100 parts by mass of the monomer.

[0041] <Chain Transfer Agent> The chain transfer agent is not particularly limited as long as it is one that is commonly used in the production of chloroprene polymers, and examples of known chain transfer agents that can be used include long-chain alkyl mercaptans such as n-dodecyl mercaptan, tert-dodecyl mercaptan, and n-octyl mercaptan, dialkyl xanthogen disulfides such as diisopropyl xanthogen disulfide and diethyl xanthogen disulfide, and iodoform. The amount of the chain transfer agent added can be 0.001 to 10 parts by mass per 100 parts by mass of all monomers.

[0042] <Polymerization temperature> The polymerization temperature is desirably in the range of 0 to 55° C. from the viewpoint of ease of reaction control, etc. From the viewpoint of carrying out the polymerization reaction more smoothly and safely, the lower limit of the polymerization temperature is desirably 5° C. or more and the upper limit is desirably 45° C. or less, more desirably less than 40° C., and even more desirably 35° C. or less.

[0043] <Polymerization rate> In the emulsion polymerization step, when the monomer reaches a desired polymerization rate, a polymerization terminator is added to terminate the polymerization, thereby obtaining a polymerization liquid in which the reaction has been completed. The polymerization rate at the end of the polymerization can be less than 100%, and can be in the range of 60 to 95%.

[0044] <Polymerization Terminator> As the polymerization terminator, for example, thiodiphenylamine, 4-tert-butylcatechol, 2,2'-methylenebis-4-methyl-6-tert-butylphenol, etc. can be used.

[0045] <Removal of Unreacted Monomer> After the completion of the emulsion polymerization, the unreacted monomer can be removed from the polymerization solution by a conventional method such as steam stripping or vacuum heating evaporation, thereby obtaining a chloroprene polymer latex.

[0046] 2.1.2 Coagulant Composition Adding and Mixing Step The method for producing a chloroprene polymer composition includes a coagulant composition adding and mixing step, in which a coagulant composition is added to and mixed with a chloroprene polymer latex containing a chloroprene polymer and water, thereby precipitating a chloroprene polymer composition containing a chloroprene polymer, the coagulant composition including at least one typical element selected from the third and fourth period elements and an acid, the coagulant composition having a pH of 0.7 to 2.5, and the amount of the coagulant composition added is 50 to 200 parts by mass per 100 parts by mass of the chloroprene polymer latex.

[0047] In the coagulant composition adding and mixing step, for example, a coagulant composition is added to and mixed with a chloroprene polymer latex containing a chloroprene polymer and water obtained by the method described above, thereby precipitating a chloroprene polymer composition containing a chloroprene polymer.

[0048] The coagulant composition has a pH of 0.7 to 2.5. The pH of the coagulant composition may be, for example, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, or 2.5, or may be within a range between any two of the values ​​exemplified here.

[0049] The coagulant composition includes at least one of the typical elements of the third and fourth periods. The at least one of the typical elements of the third and fourth periods may include at least one selected from calcium, magnesium, and aluminum, and preferably includes calcium. For example, the coagulant composition can be prepared by adding at least one of chlorides, sulfates, nitrates, and phosphates of calcium, magnesium, and aluminum. Specifically, the coagulant composition can be prepared by adding at least one of calcium chloride, magnesium chloride, magnesium sulfate, aluminum chloride, and aluminum sulfate. The amount of the metal salt of the typical element of the third and fourth periods added per 100 parts by mass of the coagulant composition may be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts by mass, or may be within a range between any two of the values ​​exemplified herein.

[0050] The coagulant composition contains an acid. The acid preferably contains at least one acid selected from acetic acid, hydrochloric acid, sulfuric acid, and nitric acid, and more preferably contains at least one acid selected from hydrochloric acid and acetic acid. The amount of acid added per 100 parts by mass of the coagulant composition is not particularly limited as long as the pH is within the above-mentioned range. For example, the amount of acid added per 100 parts by mass of the coagulant composition may be 0.005, 0.010, 0.050, 0.100, 0.200, 0.300, 0.400, 0.500, 0.600, 0.700, 0.800, or 0.900 parts by mass, or may be within a range between any two of the values ​​exemplified here.

[0051] The amount of the coagulant composition added is 50 to 200 parts by mass relative to 100 parts by mass of the chloroprene polymer latex. The amount of the coagulant composition added is, for example, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, or 200 parts by mass, and may be within a range between any two of the values ​​exemplified here.

[0052] In the coagulant composition adding and mixing step, the coagulant composition may be added to the chloroprene polymer latex all at once or may be added in portions. For example, in the coagulant composition adding and mixing step, the coagulant composition may be added to the chloroprene polymer latex all at once.

[0053] The chloroprene polymer latex and the coagulant composition can be mixed by a screw in an extruder. It is preferable to appropriately adjust the mixing conditions so that the chloroprene polymer latex and the coagulant composition are sufficiently mixed.

[0054] By adjusting the conditions in the coagulant composition adding and mixing step as described above, the content C of dehydroabietic acid and the contents of period 3 and period 4 typical elements in the resulting chloroprene polymer composition can be controlled within preferred numerical ranges, and the precipitation state of the chloroprene polymer composition can be improved. For example, it is possible to prevent the chloroprene polymer composition from being insufficiently precipitated and flowing out as a chloroprene polymer latex.

[0055] 2.1.3 Separation Step The method for producing a chloroprene polymer composition may include a separation step after the coagulant composition adding and mixing step. In the separation step, the chloroprene polymer composition containing the precipitated chloroprene polymer may be separated from water. A dehydrator may be used for the separation, and examples of the dehydrator include known dehydrators such as a slit, a strainer, or a dehydrating roll.

[0056] 2.1.4 Washing Step In the washing step, the chloroprene polymer composition is washed with water to remove at least a portion of the coagulant composition adhering to the chloroprene polymer composition. In the washing step, washing with water can be performed one or more times, and two or more times is more preferred. The amount of water supplied per washing with water per 100 parts by mass of the chloroprene polymer composition is, for example, 50, 100, 150, 200, 250, or 300 parts by mass, and may be within a range between any two of the values ​​exemplified here. By adjusting the washing step, the content C of dehydroabietic acid and the contents of third- and fourth-period main elements in the resulting chloroprene polymer composition can be controlled within preferred ranges.

[0057] 2.1.5 Drying Step The method for producing a chloroprene polymer composition may further include a drying step. In the drying step, water adhering to the chloroprene polymer composition is further removed by heating. In the drying step, the ambient temperature is preferably 130°C or less. Specific examples of the temperature in the drying step include 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, and 130°C, and may be within a range between any two of the values ​​exemplified here. The drying time in the drying step is preferably 10 minutes or less. The drying step preferably includes a high-temperature drying step in which heating is performed at 100°C or higher and a low-temperature drying step in which heating is performed at less than 100°C. In the high-temperature drying step, the ambient temperature may be, for example, 100, 110, 120, or 130°C, and may be within a range between any two of the values ​​exemplified here. The high-temperature drying step is preferably performed for 3 minutes or less. In the low-temperature drying step, the atmospheric temperature is, for example, 30, 40, 50, 60, 70, 80, 90, or 100° C., and may be within a range between any two of the values ​​exemplified here. The low-temperature drying step is preferably performed for 7 minutes or less.

[0058] 2.1.6 Other Steps The method for producing a chloroprene polymer composition may further include a molding step, in which the chloroprene polymer composition can be molded into a desired shape, for example, a sheet shape or a chip shape, by a known molding method. For example, when molding into a chip shape, known methods such as a side hot cut method and a center hot cut method can be used.

[0059] In the method for producing a chloroprene polymer composition, at least one of the coagulant composition adding and mixing step, the separating step, the washing step, the drying step, and the molding step can be performed in an extruder, preferably two or more steps, more preferably three or more steps, and even more preferably all steps can be performed in an extruder, thereby improving the working environment. Note that, for example, performing the molding step in an extruder also includes the case where only part of the molding step is performed in an extruder.

[0060] 2.2 Method for Producing Chloroprene Polymer Composition According to a Second Embodiment The method for producing a chloroprene polymer composition according to a second embodiment of the present invention includes a first coagulant composition adding and mixing step, a second coagulant composition adding and mixing step, and a washing step. In the first coagulant composition adding and mixing step, the first coagulant composition is added to and mixed with a chloroprene polymer latex containing a chloroprene polymer and water to obtain a mixed solution after the addition of the first coagulant composition. The first coagulant composition contains an acid, and the pH of the first coagulant composition is 0.7 to 4.0. The amount of the first coagulant composition added is 25 to 100 parts by mass relative to 100 parts by mass of the chloroprene polymer latex. In the coagulant composition adding and mixing step, a second coagulant composition is added to and mixed with the mixed solution obtained after the addition of the first coagulant composition to precipitate a chloroprene polymer composition containing a chloroprene polymer, the second coagulant composition containing at least one typical element selected from the third and fourth period elements, and the amount of the second coagulant composition added is 25 to 100 parts by mass per 100 parts by mass of the chloroprene polymer latex. In the washing step, the chloroprene polymer composition is washed with water to remove at least a portion of the first coagulant composition and the second coagulant composition adhering to the chloroprene polymer composition. The second embodiment will now be described, focusing on the differences from the production method according to the first embodiment.

[0061] 2.2.1 Emulsion Polymerization Step The emulsion polymerization step can be the same as in the production method according to the first embodiment.

[0062] 2.2.2 First Coagulant Composition Adding and Mixing Step The method for producing a chloroprene polymer composition includes a first coagulant composition adding and mixing step, in which the first coagulant composition is added to and mixed with a chloroprene polymer latex containing a chloroprene polymer and water to obtain a first coagulant composition added mixed liquid, the first coagulant composition containing an acid, the first coagulant composition having a pH of 0.7 to 4.0, and the amount of the first coagulant composition added is 25 to 100 parts by mass per 100 parts by mass of the chloroprene polymer latex.

[0063] In the first coagulant composition adding and mixing step, for example, the first coagulant composition is added to and mixed with a chloroprene polymer latex containing a chloroprene polymer and water obtained by the above-mentioned method, to obtain a first coagulant composition-added mixed liquid.

[0064] The pH of the first coagulant composition is 0.7 to 4.0. The pH of the first coagulant composition is, for example, 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, or 4.0, and may be within a range between any two of the values ​​exemplified here.

[0065] The first coagulant composition includes an acid. The acid preferably includes at least one acid selected from acetic acid, hydrochloric acid, sulfuric acid, and nitric acid, and more preferably includes at least one acid selected from hydrochloric acid and acetic acid. The amount of acid added per 100 parts by mass of the coagulant composition is not particularly limited as long as the pH is within the above-mentioned range. For example, the amount of acid added per 100 parts by mass of the coagulant composition may be 0.003, 0.004, 0.005, 0.010, 0.050, 0.100, 0.200, 0.300, 0.400, 0.500, 0.600, 0.700, 0.800, or 0.900 parts by mass, or may be within a range between any two of the values ​​exemplified here.

[0066] The amount of the first coagulant composition added is 25 to 100 parts by mass relative to 100 parts by mass of the chloroprene polymer latex, for example, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 parts by mass, and may be within a range between any two of the values ​​exemplified here.

[0067] In the first coagulant composition adding and mixing step, the first coagulant composition may be added to the chloroprene polymer latex all at once or may be added in portions. For example, in the first coagulant composition adding and mixing step, the first coagulant composition may be added to the chloroprene polymer latex all at once.

[0068] The chloroprene polymer latex and the first coagulant composition can be mixed by a screw in an extruder. Mixing conditions are preferably adjusted appropriately so that the chloroprene polymer latex and the first coagulant composition are thoroughly mixed. As described above, the first coagulant composition contains an acid, and the resulting mixture after adding and mixing the first coagulant composition to the chloroprene polymer latex preferably has a lower pH than the chloroprene polymer latex and a uniform pH throughout the mixture. For example, in the first coagulant composition addition and mixing step, it is preferable to perform mixing for at least 3 seconds after adding the entire first coagulant composition before performing the second coagulant composition addition and mixing step. The mixing time can be 3 seconds or more, and may be 5 seconds or more, 10 seconds or more, 30 seconds or more, or 60 seconds or more.

[0069] 2.2.3 Second Coagulant Composition Adding and Mixing Step In the second coagulant composition adding and mixing step, a second coagulant composition is added to and mixed with the mixed liquid obtained after the addition of the first coagulant composition to precipitate a chloroprene polymer composition containing a chloroprene polymer, the second coagulant composition containing at least one typical element of the third and fourth periods, and the amount of the second coagulant composition added is 25 to 100 parts by mass per 100 parts by mass of the chloroprene polymer latex.

[0070] In the second coagulant composition adding and mixing step, for example, the second coagulant composition is added to and mixed with the chloroprene polymer latex containing the chloroprene polymer and water obtained by the above-mentioned method, thereby precipitating a chloroprene polymer composition containing the chloroprene polymer.

[0071] The second coagulant composition includes at least one of the typical elements of the third and fourth periods. The at least one of the typical elements of the third and fourth periods may include at least one selected from calcium, magnesium, and aluminum, and preferably includes calcium. For example, the second coagulant composition can be prepared by adding at least one of chlorides, sulfates, nitrates, and phosphates of calcium, magnesium, and aluminum. Specifically, the second coagulant composition can be prepared by adding at least one of calcium chloride, magnesium chloride, magnesium sulfate, aluminum chloride, and aluminum sulfate. The amount of metal salt of the typical element of the third and fourth periods added per 100 parts by mass of the second coagulant composition is, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts by mass, and may be within a range between any two of the values ​​exemplified here.

[0072] The pH of the second coagulant composition is not particularly limited, but may be, for example, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7.0, 6.8, 6.9, 7, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, or 8.0, or may be within a range between any two of the values ​​exemplified here.

[0073] The amount of the second coagulant composition added is 25 to 100 parts by mass relative to 100 parts by mass of the chloroprene polymer latex, for example, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 parts by mass, and may be within a range between any two of the values ​​exemplified here.

[0074] In the second coagulant composition adding and mixing step, the second coagulant composition may be added to the mixed solution after the addition of the first coagulant composition all at once, or may be added in portions. For example, in the second coagulant composition adding and mixing step, the second coagulant composition may be added to the mixed solution after the addition of the first coagulant composition all at once.

[0075] The chloroprene polymer latex and the second coagulant composition can be mixed by a screw in an extruder. It is preferable to appropriately adjust the mixing conditions so that the mixed solution after the addition of the first coagulant composition and the second coagulant composition are sufficiently mixed.

[0076] By adjusting the conditions in the first and second coagulant composition adding and mixing steps as described above, the content C of dehydroabietic acid and the contents of period 3 and period 4 typical elements in the resulting chloroprene polymer composition can be controlled within preferred numerical ranges, and the precipitation state of the chloroprene polymer composition can be improved. For example, it is possible to prevent the chloroprene polymer composition from being insufficiently precipitated and flowing out as a chloroprene polymer latex.

[0077] 2.2.4 Separation Step, Washing Step, Drying Step, and Other Steps The separation step, washing step, drying step, and other steps can be the same as those in the production method according to the first embodiment. In the production method for a chloroprene polymer composition, at least one of the first coagulant composition adding and mixing step, the second coagulant composition adding and mixing step, the separation step, the washing step, the drying step, and the molding step can be performed in an extruder. Preferably, two or more steps can be performed in an extruder, more preferably, three or more steps can be performed in an extruder, and even more preferably, all steps can be performed in an extruder, thereby improving the working environment. Note that, for example, performing the molding step in an extruder also includes the case where only part of the molding step is performed in an extruder.

[0078] 3. Adhesive Composition An adhesive composition according to one embodiment of the present invention includes the chloroprene polymer composition. The adhesive composition according to one embodiment of the present invention may also include a solution of the chloroprene polymer composition in an organic solvent.

[0079] The type of organic solvent is not limited, and examples thereof include toluene, xylene, acetone, methyl ethyl ketone, n-hexane, cyclohexane, methylcyclohexane, cyclopentane, isopropyl acetate, and ethyl acetate. The organic solvent may be a non-aromatic solvent such as n-hexane, cyclohexane, methylcyclohexane, acetone, methyl ethyl ketone, ethyl acetate, or butyl acetate, rather than an aromatic solvent such as toluene, xylene, or ethylbenzene, which is a causative agent of sick house syndrome. It is more preferable to dissolve the chloroprene polymer rubber using only a mixture of poor solvents that have poor solubility for the chloroprene polymer rubber by themselves. One example is an organic solvent in which cyclohexane:ethyl acetate is 1:1 (mass ratio).

[0080] The amount of organic solvent used may be adjusted appropriately depending on the application and type of adhesive, and is not particularly limited. However, adjusting the viscosity of the adhesive composition to 3500 to 4500 mPa·S is preferred because it provides a good balance between the heat-resistant adhesive strength and the initial adhesive strength of the adhesive.

[0081] The adhesive composition may contain, in addition to the solvent, a metal oxide, a tackifier resin, and an antioxidant. Addition of these additives to the adhesive composition can improve the initial adhesive strength, normal adhesive strength, spray coatability, and other properties of the resulting adhesive composition.

[0082] Examples of the metal oxide that can be used include zinc oxide (zinc white), aluminum oxide, titanium oxide, and magnesium oxide. Examples of the tackifying resin that can be used include phenolic resins, rosin resins, coumarone resins, and petroleum resins.

[0083] Examples of antioxidants include 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,6-di-t-butyl-4-methylphenol, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], thiodiethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, N,N'-hexane-1,6-diylbis-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, propionamide), 3,5-bis(1,1-dimethylethyl)-4-hydroxyalkyl ester, diethyl [{3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl}methyl]phosphonate, 3,3',3",5,5',5"-hexa-t-butyl-a,a',a"-(mesitylene-2,4,6-triyl)tri-p-cresol, ethylene bis(oxyethylene) bis[3-(5-t-butyl-4-hydroxy-m-tolyl)propionate], tetraethyl thiuram disulfide, tetrabutyl thiuram disulfide, tetramethyl thiuram monosulfide, dibutylhydroxytoluene, and the like can be used.

[0084] The adhesive composition may further contain a formaldehyde catcher agent, a filler, etc. depending on the desired physical properties.

[0085] Examples of formaldehyde catcher agents that can be used include pyrrolidine, piperidine, piperazine, morpholine, melamine, dicyandiamide, urea, ethylene urea, 4,5-dimethoxyethylene urea, propylene urea, 5-methyl propylene urea, 5-hydroxypropylene urea, 5-methoxypropylene urea, oxalyl urea (parabanic acid), hydrazobenzothiazole, semicarbazide, and thiosemicarbazide. Formaldehyde catcher agents can capture formaldehyde, a harmful volatile substance.

[0086] As the filler, talc, calcium carbonate, clay, smectite, silica, hydrotalcite, mica, etc. can be used.

[0087] Furthermore, for the purpose of improving light resistance, an ultraviolet absorber such as benzotriazole or a light stabilizer such as hindered amine may be added to the adhesive composition.

[0088] The adhesive composition according to one embodiment of the present invention may further contain at least one raw rubber (uncrosslinked or unvulcanized rubber) selected from the group consisting of natural rubber, isoprene rubber, butyl rubber, nitrile rubber, hydrogenated nitrile rubber, butadiene rubber, styrene butadiene rubber, and ethylene propylene rubber.

[0089] The method for producing the adhesive composition is not particularly limited, and known machines or devices may be used. A typical method for producing the adhesive composition is to dissolve an alkylphenol resin and magnesium oxide in an organic solvent, leave the solution to stand at room temperature for 10 to 20 hours, and then dissolve chips containing chloroprene polymer rubber, a metal oxide, an antioxidant, etc.

[0090] The adhesive composition according to one embodiment of the present invention is used as an adhesive or an adhesive raw material. For example, an adhesive can be obtained by adding other additives to the adhesive composition or by mixing the adhesive composition with another adhesive composition. The adhesive can be suitably used for joining and adhering the same or different materials, such as paper, wood, cloth, leather, jersey, leather, rubber, plastic, foam, ceramic, glass, mortar, cement-based materials, ceramics, and metals.

[0091] The present invention will be described in more detail below based on examples, but the present invention should not be construed as being limited to these examples.

[0092] Example 1 Production of Chloroprene Polymer Latex Using a 5-liter reactor under a nitrogen atmosphere, 3.3 parts by mass of disproportionated gum rosin acid sodium salt 3R-70N (manufactured by Arakawa Chemical Industries, Ltd.), 0.5 parts by mass of disproportionated tall rosin acid sodium salt 6R-70N (manufactured by Harima Chemicals, Inc.), 0.4 parts by mass of a sodium salt of a condensate of naphthalenesulfonic acid and formaldehyde (trade name DEMOL N: manufactured by Kao Corporation), 0.5 parts by mass of sodium hydrogensulfite, 0.0003 parts by mass of thiourea dioxide, and 0.3 parts by mass of sodium hydroxide were dissolved in 110 parts by mass of pure water. 100 parts by mass of chloroprene monomer and 0.15 parts by mass of n-dodecyl mercaptan were emulsified into this solution, and potassium persulfate was added as a polymerization initiator. Polymerization was carried out at a polymerization temperature of 10°C under a nitrogen stream. When the polymerization conversion rate reached 72% or more, a phenothiazine emulsion was added as a polymerization terminator to terminate the reaction. Unreacted monomers were removed under reduced pressure to obtain a chloroprene polymer latex with a solid content of 40%.

[0093] <Production of Chloroprene-Based Polymer Composition> (Coagulant Composition Addition and Mixing Step) The chloroprene-based polymer latex and the coagulant composition were fed to a twin-screw extruder and mixed by the screw to precipitate a chloroprene-based polymer composition. The amount of the coagulant composition added was 67 parts by mass relative to 100 parts by mass of the chloroprene-based polymer latex. Here, the coagulant composition contained 100 parts by mass of CaCl ２ and 0.365 parts by mass of hydrochloric acid, and the pH was 1.00.

[0094] (Washing process, etc.) The resulting chloroprene polymer composition was then dehydrated using a slit to remove at least a portion of the coagulant composition and water adhering to the chloroprene polymer composition. After dehydration, the resulting chloroprene polymer composition was washed with water, and at least a portion of the coagulant composition adhering to the chloroprene polymer composition was removed. The resulting chloroprene polymer composition was then dried at 120°C until the water content was 10% by mass or less, yielding a chloroprene polymer composition. The resulting chloroprene polymer rubber was then chipped by a side hot-cut molding process. The coagulant composition addition and mixing process, washing process, drying process, and molding process were carried out in a twin-screw extruder.

[0095] Examples 2 to 4, Comparative Examples 1 to 3, 6, 7, and 10 Chloroprene polymer compositions were obtained in the same manner as in Example 1, except that the composition and amount of the coagulant composition and the water washing conditions were changed.

[0096] Example 5 <Production of Chloroprene Polymer Latex> A chloroprene polymer latex was obtained in the same manner as in Example 1.

[0097] <Production of Chloroprene Polymer Composition> (First Coagulant Composition Addition and Mixing Step) The chloroprene polymer latex and the first coagulant composition were fed into a twin-screw extruder and mixed by the screw to obtain a mixed solution after addition of the first coagulant composition. The amount of the first coagulant composition added was 67 parts by mass per 100 parts by mass of the chloroprene polymer latex 1. Here, the coagulant composition contained 0.6 parts by mass of acetic acid per 100 parts by mass of the coagulant composition and had a pH of 2.78.

[0098] (Second coagulant composition adding and mixing step) After 3 seconds or more had elapsed since the first coagulant composition was added and mixed, the second coagulant composition was further fed into the twin-screw extruder and mixed with the screw to precipitate a chloroprene polymer composition. The amount of the second coagulant composition added was 67 parts by mass relative to 100 parts by mass of the chloroprene polymer latex. Here, the coagulant composition contained 100 parts by mass of CaCl ２ The pH was 7.00.

[0099] (Washing Step, etc.) The resulting chloroprene polymer composition was then dehydrated using a slit to remove at least a portion of the coagulant composition and water adhering to the chloroprene polymer composition. After dehydration, the resulting chloroprene polymer composition was washed with water, and at least a portion of the coagulant composition adhering to the chloroprene polymer composition was removed. Washing was performed twice, using 150 parts by mass of water per 10 parts by mass of the chloroprene polymer composition per wash. The resulting chloroprene polymer composition was then dried at 120°C until the water content reached 10% by mass or less, yielding a chloroprene polymer composition. The resulting chloroprene polymer rubber was then chipped by a side hot-cut molding step. The coagulant composition addition and mixing step, washing step, drying step, and molding step were all performed in a twin-screw extruder.

[0100] Examples 6 and 7, Comparative Examples 4, 5, 8 and 9 Chloroprene polymer compositions were obtained in the same manner as in Example 5, except that the compositions and amounts of the first and second coagulant compositions and the water washing conditions were changed.

[0101] The state of precipitation during production was evaluated as follows. <State of precipitation> The wastewater discharged during dewatering using a slit was evaluated according to the following criteria. ○: The wastewater was not very turbid. ×: The wastewater was turbid. Note that turbidity of the wastewater means that precipitation (coagulation) was insufficient and the chloroprene polymer latex had leaked out. In Comparative Examples 6 to 9, the chloroprene polymer latex had leaked out, making it difficult to obtain a chloroprene polymer composition.

[0102] The obtained chloroprene polymer compositions were evaluated as follows. All of the obtained chloroprene polymer compositions had a water content of 3 mass% or less. <Content C of dehydroabietic acid present in the form of dehydroabietic acid salt> The content C of dehydroabietic acid present in the form of dehydroabietic acid salt per 100 mass parts of the chloroprene polymer composition was measured by the following measurement method.

[0103] <Measurement Method> 1. Vacuum-dry 3 g±0.03 g of the chloroprene polymer composition to obtain a dried chloroprene polymer composition with a moisture content of 0.5% by mass or less. 2. The dried chloroprene polymer composition is shredded into cubes with sides of 2-3 mm and placed in a recovery flask. 35 mL of ETA (ethanol:toluene = 70:30 vol.%) as specified in JIS K 6229 is added, and extraction is performed by heating at 90°C for 1 hour. The resulting extract is then placed in a 100 mL volumetric flask. 3. 35 mL of ETA is again added to the recovery flask containing the dried chloroprene polymer composition, and extraction is performed by heating at 90°C for 1 hour. The resulting extract is then placed in the 100 mL volumetric flask. 4. When the extract in the 100 mL volumetric flask reaches 23°C, the extract is adjusted to 100 mL with ETA to obtain a solution for analysis before acid treatment. 5. 50 mL of the pre-acid treatment analytical solution is analyzed by gas chromatography to quantify the amount of dehydroabietic acid, and the pre-acid treatment dehydroabietic acid content A per 100 parts by mass of the chloroprene polymer composition is calculated. The dehydroabietic acid content is quantified based on a calibration curve obtained by measuring a dehydroabietic acid ETA solution with a known dehydroabietic acid content. 6. 50 mL of the pre-acid treatment analytical solution is dried, a small amount (e.g., 5 to 10 mL) of ETA is added, and the solution is dissolved by ultrasonic vibration. 1 mol / L hydrochloric acid is added to adjust the pH to 1, followed by drying, dissolving in methanol, and the volume is adjusted to 50 mL to obtain a post-acid treatment analytical solution. 7. The post-acid treatment analytical solution is analyzed by gas chromatography to quantify the amount of dehydroabietic acid, and the post-acid treatment dehydroabietic acid content B per 100 parts by mass of the chloroprene polymer composition is calculated. The amount of dehydroabietic acid is determined based on a calibration curve obtained by measuring a methanol solution of dehydroabietic acid with a known content of dehydroabietic acid. 8 The content C of dehydroabietic acid present in the form of a dehydroabietic acid salt is calculated by subtracting the content A of dehydroabietic acid before acid treatment from the content B of dehydroabietic acid after acid treatment.

[0104] <Content of Typical Elements Per 100 Parts by Mass of Chloroprene-Based Polymer Composition> The content of typical elements per 100 parts by mass of the chloroprene-based polymer composition was measured using the following measurement method. First, the chloroprene-based polymer composition was vacuum-dried for 24 hours to reduce the water content to 0.5% by mass or less, and then shredded into approximately cubic pieces with a side length of approximately 5 mm. The mass of the shredded sample was measured, and this was recorded as the "mass (g) of the sample used for analysis." The shredded sample was placed in a Teflon (registered trademark) container, and 8 mL of nitric acid (for precision analysis, specific gravity 1.38) was added. The sample was decomposed using a microwave decomposition device to obtain a decomposition solution. The decomposition solution was washed into a 25 mL glass color comparison tube and the volume was adjusted to 25 mL with ultrapure water to obtain an analytical sample. The analytical sample was used for quantitative analysis using an inductively coupled plasma optical emission spectrometer (ICP-OES), with the wavelength of the element to be measured set. The "concentration of the sample for analysis (mg / L)" was determined from a calibration curve prepared using a metal standard solution. The amount of each metal element (mg / kg) contained in 1 kg of sample was calculated from the "concentration of the sample for analysis (mg / L)" and the "mass (g) of the sample used for analysis," and the content of the typical element per 100 parts by mass of the chloroprene polymer composition was calculated. Amount of metal contained in sample (mg / kg) = concentration of the sample for analysis (mg / L) × 25 ÷ mass (g) of the sample used for analysis

[0105] The analysis conditions for ICP-OES were as follows: Apparatus: 5800VDV manufactured by Agilent Accumulation time / number of times: 30 seconds / 3 times

[0106] <Preparation of 10% by mass toluene solution of chloroprene polymer composition> Toluene was added to the obtained chloroprene polymer composition to prepare a 10% by mass toluene solution of the chloroprene polymer composition, and the following evaluations were performed. The chloroprene polymer composition was vacuum-dried to a moisture content of 0.1% by mass or less before being dissolved in toluene.

[0107] (Degree of Turbidity) A 10% by mass toluene solution of the chloroprene polymer composition was placed in a transparent 225 mL glass bottle, and the degree of turbidity was visually determined and evaluated according to the following criteria: ⊚: Almost transparent ◯: Slightly turbid Δ: Turbid x: Extremely turbid

[0108] (Layer Separation Resistance) A 10% toluene solution of the chloroprene polymer composition was placed in a clear 225 mL glass bottle and allowed to stand at 23°C for 5 days, after which the appearance was observed and the layer separation resistance was evaluated according to the following evaluation criteria. Note that "haze" is an unnecessary component in toluene and water, and is thought to include resin acid salts, for example, calcium dehydroabietic acid. Present: Settling of haze is observed. Absent: Settling of haze is not observed.

[0109] (Yellowishness) A 10% toluene solution of the chloroprene polymer composition was placed in a clear 225 mL glass bottle, and the yellowishness was visually judged and evaluated according to the following evaluation criteria. The cause of the coloration is not clear, but it may be due to the structure of the chloroprene polymer, etc.: ◎: Almost colorless ○: Light yellow-green ×: Yellow-green to dark yellow-green

[0110] <Preparation of adhesive composition> 2 parts by mass of BHT (dibutylhydroxytoluene), 6 parts by mass of MgO (Kyowamag 150, manufactured by Kyowa Chemical Industry Co., Ltd.), 1 part by mass of ZnO (zinc oxide type 2, manufactured by Sakai Chemical Industry Co., Ltd.), and 50 parts by mass of alkylphenol resin (Tamanol 526, manufactured by Arakawa Chemical Industries Co., Ltd.) were added to 100 parts by mass of a chloroprene polymer composition, and a solvent consisting of cyclohexane and methyl ethyl ketone in a ratio of 1:1 (by mass) was added to the mixture to give a solution viscosity of 4000±400 mPa s to prepare an adhesive composition. The chloroprene polymer composition was vacuum-dried to a moisture content of 0.1% by mass or less before use in preparing the adhesive composition.

[0111] (Storage Stability) The adhesive composition was allowed to stand at 23°C, and the time until layer separation occurred was evaluated according to the following criteria: ⊚: No layer separation was observed even after 7 days; ◯: Layer separation was observed within 7 days or more, but not more than 4 days; Δ: Layer separation was observed within 4 days or more, but not more than 2 days; ×: Layer separation was observed within 2 days

[0112]

[0113]

Claims

1. A chloroprene polymer composition containing a chloroprene polymer, wherein the chloroprene polymer composition has a water content of 10% by mass or less, and a content C of dehydroabietic acid present in the form of a dehydroabietic acid salt relative to 100 parts by mass of the chloroprene polymer composition, as measured by the following measurement method, is 0.075 to 1.600 parts by mass. <Measurement Method> 1. 3 g±0.03 g of the chloroprene polymer composition is vacuum-dried to obtain a dried chloroprene polymer composition having a water content of 0.5% by mass or less.

2. The dried chloroprene polymer composition is shredded into cubes measuring 2 to 3 mm on a side and placed in an eggplant flask. 35 mL of ETA (ethanol:toluene = 70:30 vol%) specified in JIS K 6229 is added, and the resulting mixture is heated and extracted at 90°C for 1 hour. The resulting extract is then placed in a 100 mL volumetric flask.

3. 35 mL of ETA is added again to the recovery flask containing the dried chloroprene polymer composition, and the mixture is heated and extracted at 90°C for 1 hour. The resulting extract is then added to the 100 mL volumetric flask.

4. When the extract in the 100 mL volumetric flask reaches 23°C, the extract is adjusted to 100 mL with ETA to obtain a solution for analysis before acid treatment.

5. 50 mL of the solution for analysis before acid treatment is analyzed by gas chromatography to quantify the amount of dehydroabietic acid, and the pre-acid treatment dehydroabietic acid content A per 100 parts by mass of the chloroprene polymer composition is calculated. The amount of dehydroabietic acid is quantified based on a calibration curve obtained by measuring a dehydroabietic acid ETA solution with a known dehydroabietic acid content.

6. 50 mL of the pre-acid treatment analytical solution is dried, a small amount of ETA is added, and the solution is dissolved by ultrasonic vibration. 1 mol / L hydrochloric acid is added to adjust the pH to 1, followed by drying, dissolving in methanol, and the volume is adjusted to 50 mL to obtain a post-acid treatment analytical solution.

7. The post-acid treatment analytical solution is analyzed by gas chromatography to quantify the amount of dehydroabietic acid, and the post-acid treatment dehydroabietic acid content B per 100 parts by mass of the chloroprene polymer composition is calculated. The amount of dehydroabietic acid is quantified based on a calibration curve obtained by measuring a dehydroabietic acid methanol solution with a known dehydroabietic acid content.

8. The content C of dehydroabietic acid present in the form of dehydroabietic acid salt is calculated by subtracting the content A of dehydroabietic acid before acid treatment from the content B of dehydroabietic acid after acid treatment.

2. The chloroprene polymer composition according to claim 1, which contains at least one typical element selected from the group consisting of period 3 and period 4 typical elements, and the content of the typical element per 100 parts by mass of the chloroprene polymer composition is 0.005 to 0.100 parts by mass.

3. The chloroprene polymer composition according to claim 2, wherein the main group element includes at least one selected from calcium, magnesium, and aluminum.

4. The chloroprene polymer composition according to claim 1 or 2, which is used as an adhesive containing an organic solvent.

5. A method for producing a chloroprene polymer composition, comprising: a coagulant composition adding and mixing step; and a washing step; wherein in the coagulant composition adding and mixing step, a coagulant composition is added to and mixed with a chloroprene polymer latex containing a chloroprene polymer and water, thereby precipitating a chloroprene polymer composition containing the chloroprene polymer; the coagulant composition contains at least one typical element selected from the third and fourth period elements and an acid; the coagulant composition has a pH of 0.7 to 2.5; the coagulant composition is added in an amount of 50 to 200 parts by mass per 100 parts by mass of the chloroprene polymer latex; and in the washing step, the chloroprene polymer composition is washed with water to remove at least a portion of the coagulant composition adhering to the chloroprene polymer composition.

6. A method for producing a chloroprene polymer composition, comprising a first coagulant composition adding and mixing step, a second coagulant composition adding and mixing step, and a washing step, wherein in the first coagulant composition adding and mixing step, a first coagulant composition is added to and mixed with a chloroprene polymer latex containing a chloroprene polymer and water to obtain a first coagulant composition added mixed solution, the first coagulant composition contains an acid, the first coagulant composition has a pH of 0.7 to 4.0, and the amount of the first coagulant composition added is 25 to 100 parts by mass per 100 parts by mass of the chloroprene polymer latex, and in the second coagulant composition adding and mixing step, a second coagulant composition is added to and mixed with the first coagulant composition added mixed solution to precipitate a chloroprene polymer composition containing the chloroprene polymer, and the second coagulant composition contains at least one typical element selected from the group consisting of third and fourth period elements, the second coagulant composition is added in an amount of 25 to 100 parts by mass relative to 100 parts by mass of the chloroprene polymer latex; and in the washing step, the chloroprene polymer composition is washed with water to remove at least a part of the first coagulant composition and the second coagulant composition adhering to the chloroprene polymer composition.

7. A method for producing a chloroprene polymer composition according to claim 5 or 6, wherein the acid comprises at least one acid selected from the group consisting of acetic acid, hydrochloric acid, sulfuric acid and nitric acid.

8. A method for producing the chloroprene polymer composition according to claim 5 or 6, wherein at least a part of the steps is carried out in an extruder.

9. An adhesive composition comprising the chloroprene polymer composition according to claim 1 or 2.

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