Chloroprene-based polymer composition, method for producing chloroprene-based polymer composition, adhesive composition

Abstract

The present application provides a neoprene polymer composition which is not easily subjected to layer separation and coloring when mixed with a solvent, has excellent storage stability when an adhesive composition is prepared, and a method for producing the neoprene polymer composition. According to the present application, a neoprene polymer composition containing a neoprene polymer, the moisture content of which is 10 mass% or less, and the content C of dehydroabietic acid in the form of a dehydroabietate salt with respect to 100 parts by mass of the neoprene polymer composition is 0.075 to 1.600 parts by mass, as measured by a specific measurement method.

Description

Technical Field

[0001] This invention relates to a chloroprene-based polymer composition, a method for manufacturing the chloroprene-based polymer composition, and an adhesive composition. Background Technology

[0002] Chloroprene polymers are materials with excellent heat resistance, weather resistance, ozone resistance, chemical resistance, and flame retardancy (self-extinguishing properties), exhibiting many superior characteristics compared to natural rubber or other synthetic resins. These chloroprene polymers, with their well-balanced overall physical properties, are used in a variety of applications, including, for example, as adhesives.

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

[0004] [Existing Technical Documents]

[0005] [Patent Literature]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2012-111862 Summary of the Invention

[0007] [The problem the invention aims to solve]

[0008] However, existing chloroprene-based polymer compositions sometimes experience layer separation and discoloration when mixed with solvents. Furthermore, there is room for improvement in the storage stability during the preparation of adhesive compositions.

[0009] The present invention was made in view of the above circumstances, and aims to provide a chloroprene-based polymer composition that is not prone to layer separation and coloring when mixed with a solvent and has excellent storage stability when preparing an adhesive composition, a method for manufacturing the chloroprene-based polymer composition, and an adhesive composition.

[0010] [Technical solution used to solve the problem]

[0011] According to the present invention, a chloroprene-based polymer composition is provided, which contains a chloroprene-based polymer, wherein the moisture content of the chloroprene-based polymer composition is less than 10% by mass, and the content C of dehydroabietic acid in the form of dehydroabirate relative to 100 parts by mass of the chloroprene-based polymer composition, as determined by the following determination method, is 0.075 to 1.600 parts by mass.

[0012] <Determination Method>

[0013] 1. Vacuum dry 3g±0.03g of the chloroprene polymer composition to obtain a dried chloroprene polymer composition with a moisture content of less than 0.5% by mass.

[0014] 2. Cut the dried chloroprene polymer composition into cubes with a side length of 2-3 mm and place them in a flask. Add 35 mL of ETA (ethanol:toluene = 70:30 vol%) as specified in JIS K 6229. Heat and extract at 90 °C for 1 hour. Transfer only the resulting extract to a 100 mL volumetric flask.

[0015] 3. Add 35 mL of LETA to the flask containing the dried chloroprene polymer composition again, heat and extract at 90°C for 1 hour, and transfer only the resulting extract to the 100 mL volumetric flask.

[0016] 4. When the extract in the 100mL volumetric flask reaches 23°C, dilute the extract to 100mL with ETA to obtain an analytical solution before acid treatment.

[0017] 5. Analyze 50 mL of the solution before acid treatment using gas chromatography to quantify dehydroabietic acid and calculate the dehydroabietic acid content A relative to 100 parts by mass of the chloroprene polymer composition before acid treatment. The quantification of dehydroabietic acid is based on a calibration curve obtained by measuring dehydroabietic acid ETA solutions with known dehydroabietic acid content.

[0018] 6. Dry 50 mL of the pre-acid-treated analytical solution, add a small amount of ETA and apply ultrasonic vibration to dissolve it, add 1 mol / L hydrochloric acid to adjust the pH to 1 and then dry it, dissolve it with methanol and make up to 50 mL to obtain the post-acid-treated analytical solution.

[0019] 7. The acid-treated analytical solution is analyzed using a gas chromatograph to quantify dehydroabietic acid and calculate the dehydroabietic acid content B relative to 100 parts by mass of the chloroprene polymer composition. The quantification of dehydroabietic acid is based on a calibration curve obtained by measuring a methanol solution of dehydroabietic acid with a known content of dehydroabietic acid.

[0020] 8. Subtract the content of dehydroabietic acid before acid treatment (A) from the content of dehydroabietic acid after acid treatment (B) to calculate the content of dehydroabietic acid in the form of dehydroabiate (C).

[0021] Through diligent research, the inventors discovered that by precisely controlling the content C of dehydroabirate in the form of dehydroabirate in chloroprene polymer compositions with a water content below a certain value after precipitation, chloroprene polymer compositions that are less prone to layer separation and coloring when mixed with solvents and exhibit excellent storage stability when preparing adhesive compositions can be obtained, thus completing this invention.

[0022] The following describes various embodiments of the present invention. These embodiments can be combined with each other.

[0023] [1] A chloroprene polymer composition containing a chloroprene polymer, wherein the moisture content of the chloroprene polymer composition is less than 10% by mass, and the content C of dehydroabietic acid in the form of dehydroabirate relative to 100 parts by mass of the chloroprene polymer composition, as determined by the following determination method, is 0.075 to 1.600 parts by mass.

[0024] <Determination Method>

[0025] 1. Vacuum dry 3g±0.03g of the chloroprene polymer composition to obtain a dried chloroprene polymer composition with a moisture content of less than 0.5% by mass.

[0026] 2. Cut the dried chloroprene polymer composition into cubes with a side length of 2-3 mm and place them in a flask. Add 35 mL of ETA (ethanol:toluene = 70:30 vol%) as specified in JIS K 6229. Heat and extract at 90 °C for 1 hour. Transfer only the resulting extract to a 100 mL volumetric flask.

[0027] 3. Add 35 mL of LETA to the flask containing the dried chloroprene polymer composition again, heat and extract at 90°C for 1 hour, and transfer only the resulting extract to the 100 mL volumetric flask.

[0028] 4. When the extract in the 100mL volumetric flask reaches 23°C, dilute the extract to 100mL with ETA to obtain an analytical solution before acid treatment.

[0029] 5. Analyze 50 mL of the solution before acid treatment using gas chromatography to quantify dehydroabietic acid and calculate the dehydroabietic acid content A relative to 100 parts by mass of the chloroprene polymer composition before acid treatment. The quantification of dehydroabietic acid is based on a calibration curve obtained by measuring dehydroabietic acid ETA solutions with known dehydroabietic acid content.

[0030] 6. Dry 50 mL of the pre-acid-treated analytical solution, add a small amount of ETA and apply ultrasonic vibration to dissolve it, add 1 mol / L hydrochloric acid to adjust the pH to 1 and then dry it, dissolve it with methanol and make up to 50 mL to obtain the post-acid-treated analytical solution.

[0031] 7. The acid-treated analytical solution is analyzed using a gas chromatograph to quantify dehydroabietic acid and calculate the dehydroabietic acid content B relative to 100 parts by mass of the chloroprene polymer composition. The quantification of dehydroabietic acid is based on a calibration curve obtained by measuring a methanol solution of dehydroabietic acid with a known content of dehydroabietic acid.

[0032] 8. Subtract the content of dehydroabietic acid before acid treatment (A) from the content of dehydroabietic acid after acid treatment (B) to calculate the content of dehydroabietic acid in the form of dehydroabiate (C).

[0033] [2] The chloroprene polymer composition described in [1] contains at least one main group element from the third and fourth periods, wherein the content of the main group element is 0.005 to 0.100 parts by mass relative to 100 parts by mass of the chloroprene polymer composition.

[0034] [3] The chloroprene polymer composition described in [2], wherein the main group element includes at least one selected from calcium, magnesium and aluminum.

[0035] [4] A chloroprene polymer composition as described in any of [1] to [3], used in an adhesive containing an organic solvent.

[0036] [5] A method for manufacturing a chloroprene polymer composition, comprising a coagulant composition addition and mixing step and a washing step, wherein in the coagulant composition addition and mixing step, a coagulant composition is added to and mixed with a chloroprene polymer latex containing a chloroprene polymer and water, so that the chloroprene polymer composition containing the chloroprene polymer precipitates out, wherein the coagulant composition contains at least one main group element from the third and fourth period main group elements and an acid, wherein the pH of the coagulant composition is 0.7 to 2.5, and the amount of the coagulant composition added is 50 to 200 parts by weight relative to 100 parts by weight of the chloroprene polymer latex, wherein 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.

[0037] [6] A method for manufacturing a chloroprene polymer composition, comprising a first coagulant composition addition and mixing step, a second coagulant composition addition and mixing step, and a washing step, wherein in the first coagulant composition addition and mixing step, a first coagulant composition is added to a chloroprene polymer latex containing a chloroprene polymer and water and mixed to obtain a mixture after the addition of the first coagulant composition, wherein the first coagulant composition contains an acid, the pH of the first coagulant composition is 0.7 to 4.0, and the amount of the first coagulant composition added is 25 to 100 parts by weight relative to 100 parts by weight of the chloroprene polymer latex, and the second coagulant composition... In the addition and mixing step, a second coagulant composition is added to the mixture after the first coagulant composition is added and mixed to precipitate the chloroprene polymer composition containing the chloroprene polymer. The second coagulant composition contains at least one main group element from the third and fourth periods. The amount of the second coagulant composition added is 25 to 100 parts by weight relative to 100 parts by weight 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.

[0038] [7] A method for manufacturing a chloroprene polymer composition as described in [5] or [6], wherein the acid comprises at least one acid selected from acetic acid, hydrochloric acid, sulfuric acid and nitric acid.

[0039] [8] A method for manufacturing a chloroprene polymer composition as described in any of [5] to [7], wherein at least some steps are carried out in an extruder.

[0040] [9] An adhesive composition comprising a chloroprene polymer composition described in any one of [1] to [4].

[0041] [Invention Effects]

[0042] According to the present invention, a chloroprene-based polymer composition that is not prone to delamination and coloring when mixed with a solvent and exhibits excellent storage stability when preparing an adhesive composition can be obtained. Furthermore, according to the present invention, a method for manufacturing the above-mentioned chloroprene-based polymer composition is provided. Additionally, according to the present invention, an adhesive composition exhibiting excellent delamination resistance, minimal coloring, and excellent storage stability is provided. Detailed Implementation

[0043] The present invention will now be described in detail with reference to embodiments thereof. The present invention is not limited thereto by these descriptions. The features of the embodiments of the present invention shown below can be combined with each other. Furthermore, the invention can be established independently for each feature.

[0044] 1. Chloroprene-based polymer composition

[0045] The chloroprene-based polymer composition of the present invention contains a chloroprene-based polymer. Furthermore, the moisture content of the chloroprene-based polymer composition of the present invention is 10% by mass or less, and the content C of dehydroabietic acid present in the form of dehydroabirate, relative to 100 parts by mass of the chloroprene-based polymer composition, as determined by a specific measurement method, is 0.075 to 1.600 parts by mass.

[0046] 1.1 Chloroprene-based polymers

[0047] The chloroprene-based polymer composition of the present invention contains a chloroprene-based polymer. Furthermore, the chloroprene-based polymer of the present invention may be a homopolymer of 2-chloro-1,3-butadiene (hereinafter referred to as chloroprene), or a copolymer of chloroprene monomer and other monomers that can be copolymerized therewith.

[0048] The chloroprene-based polymer of one embodiment of the present invention may also be a copolymer of chloroprene and other monomers that can copolymerize with chloroprene. As for other monomers, there are no particular limitations as long as they can copolymerize with chloroprene monomers. Examples include esters of (meth)acrylic acid (methyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, etc.), hydroxyalkyl esters of (meth)acrylic acid (2-hydroxymethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, etc.), 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, butadiene, isoprene, unsaturated nitrile, ethylene, styrene, sulfur, etc.

[0049] While there are no particular limitations, from the viewpoint of maintaining the properties derived from chloroprene, in the chloroprene-based polymer of one embodiment of the present invention, when the chloroprene-based polymer is set to 100% by mass, it is preferable to contain 70% by mass or more of monomer units derived from chloroprene monomer, more preferably 90% by mass or more. The content of monomer units derived from chloroprene monomer can be, for example, 70, 75, 80, 85, 90, 95, or 100% by mass, or can be within any range between the values ​​exemplified herein. When the content of monomer units derived from chloroprene monomer in the chloroprene-based polymer is at or above the aforementioned lower limit, the crystallinity of the chloroprene-based polymer is improved, and the adhesive strength of the adhesive composition containing this chloroprene-based polymer is further improved after a long period of time.

[0050] 1.2 Moisture Content

[0051] The chloroprene polymer composition of the present invention has a moisture content of 10% by mass or less. The manufacturing method will be described later. One embodiment of the chloroprene polymer composition of the present invention can be obtained by adding a coagulant composition to a chloroprene polymer latex containing a chloroprene polymer, causing the chloroprene polymer composition to precipitate, and then removing the water. One embodiment of the chloroprene polymer composition of the present invention can be a composition comprising a chloroprene polymer (rubber) precipitated (coagulated) from a chloroprene polymer latex using a coagulant composition.

[0052] The chloroprene-based polymer composition is permitted to contain less than 10.0% by mass of water relative to 100% by mass of the chloroprene-based polymer composition. The water content can 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 any range between the values ​​exemplified herein. The solid content concentration of the chloroprene-based 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, or any value between the two examples listed herein.

[0053] 1.3 Content of dehydroabietic acid in the form of dehydroabirate C

[0054] In the chloroprene polymer composition of the present invention, the content C of dehydroabietic acid in the form of dehydroabirate, as measured by a specific determination method, is 0.075 to 1.600 parts by mass relative to 100 parts by mass of the chloroprene polymer composition, preferably 0.075 parts by mass or more and less than 0.750 parts by mass. The content C of dehydroabietic acid in the form of dehydroabirate is, 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 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, or any range between any two of the values ​​exemplified here.

[0055] In this invention, the amount of dehydroabietic acid measured by the following method is defined as "the content C of dehydroabietic acid existing in the form of dehydroabiate".

[0056] <Determination Method>

[0057] 1. Vacuum dry 3g±0.03g of the chloroprene polymer composition to obtain a dried chloroprene polymer composition with a moisture content of less than 0.5% by mass.

[0058] 2. Cut the dried chloroprene polymer composition into cubes (polyhedra, such as cubes, cuboids, etc.) with a side length of 2-3 mm and place them in a round-bottom flask. Add 35 mL of ETA (ethanol:toluene = 70:30 vol%) as specified in JIS K 6229, heat and extract at 90 °C for 1 hour, and transfer only the resulting extract to a 100 mL volumetric flask.

[0059] 3. Add 35 mL of LETA to the flask containing the dried chloroprene polymer composition again, heat and extract at 90°C for 1 hour, and transfer only the resulting extract to the 100 mL volumetric flask.

[0060] 4. When the extract in the 100mL volumetric flask reaches 23°C, dilute the extract to 100mL with ETA to obtain an analytical solution before acid treatment.

[0061] 5. Analyze 50 mL of the solution before acid treatment using gas chromatography to quantify dehydroabietic acid and calculate the dehydroabietic acid content A relative to 100 parts by mass of the chloroprene polymer composition before acid treatment. The quantification of dehydroabietic acid is based on a calibration curve obtained by measuring dehydroabietic acid ETA solutions with known dehydroabietic acid content.

[0062] 6. Dry 50 mL of the pre-acid-treated analytical solution, add a small amount of ETA and apply ultrasonic vibration to dissolve it, add 1 mol / L hydrochloric acid to adjust the pH to 1 and then dry it, dissolve it with methanol and make up to 50 mL to obtain the post-acid-treated analytical solution.

[0063] 7. The acid-treated analytical solution is analyzed using a gas chromatograph to quantify dehydroabietic acid and calculate the dehydroabietic acid content B relative to 100 parts by mass of the chloroprene polymer composition. The quantification of dehydroabietic acid is based on a calibration curve obtained by measuring a methanol solution of dehydroabietic acid with a known content of dehydroabietic acid.

[0064] 8. Subtract the content of dehydroabietic acid before acid treatment (A) from the content of dehydroabietic acid after acid treatment (B) to calculate the content of dehydroabietic acid in the form of dehydroabiate (C).

[0065] According to the present invention, by ensuring that the "content C of dehydroabirate in the form of dehydroabirate" as measured by the above-described method falls within the aforementioned numerical range, a chloroprene-based polymer composition exhibiting excellent storage stability when mixed with a solvent and less prone to layer separation and discoloration can be obtained. In particular, by ensuring that the content C of dehydroabirate in the form of dehydroabirate is above or below the aforementioned lower limit, a chloroprene-based polymer composition exhibiting excellent storage stability when mixed with a solvent and less prone to discoloration can be obtained. Furthermore, by ensuring that the content C of dehydroabirate in the form of dehydroabirate is below or below the aforementioned upper limit, a chloroprene-based polymer composition exhibiting excellent storage stability when mixed with a solvent and less prone to layer separation can be obtained. Moreover, turbidity is less likely to occur when mixed with a solvent. Although the mechanism is not yet fully understood, it is hypothesized as follows. It should be noted that the following hypothesized mechanism does not limit the present invention.

[0066] The chloroprene-based polymers of the present invention can be obtained by a manufacturing method including a polymerization step, in which a raw material monomer containing chloroprene and other monomers as desired is emulsified and polymerized using an emulsifier containing abietic acid. It should be noted that dehydroabietic acid is one of the main components of abietic acid. Furthermore, abietic acid salts exist in water-soluble and water-insoluble forms. For example, alkali metal salts such as sodium and potassium are water-soluble, while salts of third- and fourth-period main group elements such as calcium, magnesium, and aluminum are water-insoluble. Additionally, the coagulant composition used to precipitate the chloroprene-based polymer composition containing the chloroprene-based polymer in the mixing step may contain third- and fourth-period main group elements such as calcium, magnesium, and aluminum. Therefore, the chloroprene-based polymer composition obtained by the manufacturing method including the coagulant composition addition and mixing step may contain abietic acid salts of third- and fourth-period main group elements in a water-insoluble form. The content of dehydroabietic acid (C) in the form of dehydroabirate, as determined by the above method, is considered an indicator of the amount of water-insoluble rosin acid salts contained in chloroprene polymer compositions.

[0067] The "content C of dehydroabietic acid in the form of dehydroabirate" of the present invention is calculated by adding a solvent to a chloroprene-based polymer composition to obtain an extract containing abietic acid, and by the difference between the dehydroabietic acid content analysis results of the solution containing the extract before acid treatment (dehydroabietic acid content A before acid treatment) and the dehydroabietic acid content analysis results of the solution containing the extract after acid treatment (dehydroabietic acid content B after acid treatment). Here, the dehydroabietic acid content A before acid treatment is considered to correspond to abietic acid that has not participated in the formation of a water-insoluble salt. In addition, after acid treatment, the abiate anion (abietic acid anion) that participated in the formation of a water-insoluble salt is restored to abietic acid. Therefore, the dehydroabietic acid content B after acid treatment is considered to correspond to the sum of abietic acid that has not participated in the formation of a water-insoluble salt and abietic acid that participated in the formation of a water-insoluble salt. Therefore, it is hypothesized that the content C of dehydroabirate salts, especially the content C of dehydroabirate salts, existing in the form of salts of third- and fourth-period main group elements such as calcium, magnesium, and aluminum, can be calculated by subtracting the content A of dehydroabirate before acid treatment from the content B of dehydroabirate after acid treatment.

[0068] In this invention, it is speculated that by specifying an upper limit for the content C of dehydroabietic acid in the form of dehydroabirate, the amount of water-insoluble salts in the chloroprene polymer composition is kept below a certain value, thereby preventing layer separation when mixed with organic solvents or deterioration of storage stability during the preparation of adhesive compositions. Furthermore, by specifying a lower limit for the content C of dehydroabirate of dehydroabirate and adjusting the amount of water-insoluble salts in the chloroprene polymer composition to a certain value or higher, chloroprene polymer compositions are less prone to coloring when mixed with solvents. Although the mechanism is not yet clear, it is believed that coloring may be due to the structure of the chloroprene polymer, etc. By specifying a lower limit for the content C of dehydroabirate of dehydroabirate, the structure of the chloroprene polymer can be indirectly controlled, thereby reducing coloring.

[0069] The content C of dehydroabsic acid in the form of dehydroabsicate can be controlled by finely adjusting the manufacturing method of the chloroprene polymer composition. For example, it can be controlled by adjusting the composition, amount, pH, number of additions, presence or absence of a water washing step, amount of water used, and number of water washing steps in the mixing step of the coagulant composition used to precipitate the chloroprene polymer composition containing the chloroprene polymer.

[0070] 1.4 Main group elements (typical elements) of the third and fourth periods

[0071] The chloroprene-based polymer composition of one embodiment of the present invention may contain at least one main group element from the third and fourth periods. The content of the third and fourth period main group element relative to 100 parts by mass of the chloroprene-based polymer composition may be 0.005 to 0.100 parts by mass. Preferably, the content of the third and fourth period main group element is 0.005 parts by mass or more and less than 0.100 parts by mass. The content of the third and fourth period main group element may be, 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, or 0.100 parts by mass, or may be within any range between the values ​​exemplified herein.

[0072] Chloroprene-based polymer compositions in which the contents of Group 3 and Group 4 elements are adjusted to the lower limit mentioned above are less prone to coloring when mixed with solvents. Furthermore, by keeping the contents of Group 3 and Group 4 elements below the upper limit mentioned above, the amount of salts that are not easily soluble in solvents can be kept below a certain level, resulting in chloroprene-based polymer compositions that are less prone to layer separation and turbidity when mixed with solvents and exhibit excellent storage stability when preparing adhesive compositions.

[0073] It should be noted that, in this invention, "the content of third- and fourth-period group elements relative to 100 parts by mass of the chloroprene-based polymer composition" refers to the content of third- and fourth-period group elements measured by inductively coupled plasma optical emission spectrometry (ICP-OES) according to the method described in the examples. The third- and fourth-period group elements contained in the chloroprene-based polymer composition may include third- and fourth-period group elements existing in salt form and third- and fourth-period group elements existing in ionic form.

[0074] The main group elements in the third and fourth periods may include at least one selected from calcium, magnesium, and aluminum, preferably calcium. The main group elements in the third and fourth periods may be derived from a coagulant composition used to precipitate chloroprene polymers (compositions) from chloroprene polymer latex.

[0075] The content of main group elements in the third and fourth periods can be controlled by finely adjusting the manufacturing method of chloroprene polymer compositions. For example, it can be controlled by adjusting the composition, amount, pH, number of additions, presence or absence of a water washing step, amount of water used, and number of water washing steps in the coagulant composition addition and mixing step used to precipitate chloroprene polymer compositions containing chloroprene polymers.

[0076] 1.5 Other ingredients

[0077] The chloroprene-based polymer composition of one embodiment of the present invention may, for example, contain trace amounts of reagents or other components used in the manufacture of chloroprene-based polymer latex. Examples of such other components include monomers such as chloroprene monomers, dispersants other than rosin acid, emulsifiers, polymerization initiators, chain transfer agents, polymerization inhibitors, polymerization terminators, and defoamers. In the chloroprene-based polymer composition, the content of the chloroprene polymer relative to 100% by mass of the chloroprene polymer composition is, for example, 80, 85, 90, 95, or 100% by mass, or may be within any range between the values ​​exemplified herein.

[0078] 1.6 Properties of Chloroprene-based Polymer Compositions

[0079] When the chloroprene polymer composition of one embodiment of the present invention is vacuum dried to reduce the moisture content to less than 0.1% by mass, and then dissolved in toluene to prepare a 10% by mass toluene solution of the chloroprene polymer composition, the toluene solution preferably has the following characteristics.

[0080] When a 10% by mass toluene solution of a chloroprene-based polymer composition is placed in a transparent 225 mL glass bottle and visually observed, it is preferable that no turbidity is observed. Furthermore, the 10% by mass toluene solution is preferably colorless and does not exhibit a yellow-green tint.

[0081] Furthermore, when a 10% toluene solution of the chloroprene-based polymer composition is placed in a transparent 225 mL glass bottle and allowed to stand at 23°C for 5 days, it is preferable that no layer separation occurs; specifically, it is preferable that no sedimentation of the mist is observed. It should be noted that the "mist" refers to components insoluble in toluene and water, and is believed to contain resin salts, such as calcium dehydroabirate.

[0082] When preparing an adhesive composition by adding 2 parts by mass of BHT (butylated hydroxytoluene), 6 parts by mass of MgO (Kyowa Chemical Industry Co., Ltd., Kyowamag 150), 1 part by mass of ZnO (Sakai Chemical Industry Co., Ltd., Zinc Oxide No. 2), and 50 parts by mass of alkylphenol resin (Arakawa Chemical Industry Co., Ltd., Tamanol 526) to 100 parts by mass of the chloroprene polymer composition of one embodiment of the present invention, and further adding a solvent of cyclohexane:methyl ethyl ketone = 1:1 (mass ratio) to make the solution viscosity 4000±400 mPa·s, it is preferable that no layer separation is observed after more than 2 days, more preferably no layer separation is observed after more than 4 days, and even more preferably no layer separation is observed after more than 7 days.

[0083] 1.7 Applications

[0084] The chloroprene-based polymer composition of one embodiment of the present invention exhibits excellent storage stability when mixed with solvents, exhibiting minimal layer separation and coloring upon mixing with solvents. Furthermore, the chloroprene-based polymer composition of one embodiment of the present invention does not produce turbidity upon mixing with solvents. Therefore, the chloroprene-based polymer composition of one embodiment of the present invention is suitable for applications involving mixing with organic solvents, such as adhesives containing organic solvents.

[0085] 2. Method for manufacturing chloroprene-based polymer compositions

[0086] The method for manufacturing the chloroprene-based polymer composition according to one embodiment of the present invention is not particularly limited, and may include a coagulant composition addition and mixing step and a washing step. Hereinafter, the manufacturing methods of the first embodiment and the second embodiment will be described as examples.

[0087] 2.1 Method for manufacturing the chloroprene-based polymer composition of the first embodiment

[0088] The method for manufacturing a chloroprene polymer composition according to the first embodiment of the present invention includes a coagulant composition addition and mixing step and a washing step. In the coagulant composition addition and mixing step, a coagulant composition is added to and mixed with a chloroprene polymer latex containing a chloroprene polymer and water, causing the chloroprene polymer composition containing the chloroprene polymer to precipitate. The coagulant composition contains at least one main group element from the third and fourth periods and an acid. The pH of the coagulant composition is 0.7 to 2.5. The amount of coagulant composition added is 50 to 200 parts by weight relative to 100 parts by weight 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.

[0089] The manufacturing method of the first embodiment will be described below.

[0090] 2.1.1 Emulsification Polymerization Step

[0091] A method for manufacturing chloroprene-based polymer compositions may include an emulsification polymerization step prior to the mixing and washing steps of the aforementioned coagulant composition. In the emulsification polymerization step, emulsifiers, dispersants, polymerization initiators, chain transfer agents, etc., may be appropriately used to emulsify and polymerize a raw material monomer containing chloroprene monomer, or containing chloroprene monomer and other monomers that can copolymerize with it. When the target polymerization rate is reached, a polymerization terminator is added to obtain a chloroprene-based polymer latex. Furthermore, unreacted monomers can be removed from the chloroprene-based polymer latex obtained in this manner using methods such as steam flash or concentration.

[0092] <Emulsifiers and Dispersants>

[0093] As emulsifiers, known anionic, nonionic, and cationic emulsifiers used in the polymerization of chloroprene-based polymers can be used.

[0094] As anionic emulsifiers, there are carboxylic acid type, sulfonic acid type, and sulfate ester type, such as higher fatty acid salts, alkenyl succinates, alkali metal salts of rosin acid, alkyl sulfonates with 8 to 20 carbon atoms, alkyl aryl sulfates, and condensates of sodium naphthalene sulfonate and formaldehyde.

[0095] Examples of 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), substances obtained by chemically modifying these (co)polymers, or cellulose derivatives (hydroxyethyl cellulose), and the like.

[0096] Examples of cationic emulsifiers include aliphatic amine salts, aliphatic quaternary ammonium salts and the like, and specific examples thereof include octadecyltrimethylammonium chloride, dodecyltrimethylammonium chloride, dilauryl dimethylammonium chloride, and the like.

[0097] Herein, in the present 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 thereof.

[0098] The amount of the emulsifier may be 2.0 to 7.5 parts by mass relative to 100 parts by mass of the monomers.

[0099] <pH Adjusting Agent>

[0100] The raw materials added to the polymerization system at the start of polymerization may contain a pH adjusting agent. Examples of the pH adjusting agent include potassium metabisulfite, potassium sulfite, potassium bisulfite, potassium phosphate, potassium hydrogen phosphate, sodium metabisulfite, sodium sulfite, sodium bisulfite, sodium phosphate, sodium hydrogen phosphate, potassium hydroxide, sodium hydroxide, and the like. These pH adjusting agents may be used alone, or two or more thereof may be used in combination. Among these pH adjusting agents, use of potassium hydroxide or sodium hydroxide is preferred because of their high effect of increasing the pH value. The addition amount of the pH adjusting agent may be 0.01 to 2.0 parts by mass relative to 100 parts by mass of the monomers.

[0101] <Polymerization Initiator>

[0102] The raw materials added to the polymerization system at the start of polymerization may contain a polymerization initiator. As the polymerization initiator, those commonly used in conventional radical polymerization such as potassium persulfate, benzoyl peroxide, ammonium persulfate, and hydrogen peroxide can be used. The addition amount of the polymerization initiator may be 0.001 to 1 part by mass relative to 100 parts by mass of the monomers.

[0103] <Chain Transfer Agent>

[0104] The chain transfer agent is not particularly limited as long as it is a chain transfer agent commonly used in the production of chloroprene-based polymers, and for example, known chain transfer agents such as 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 can be used. The addition amount of the chain transfer agent may be 0.001 to 10 parts by mass relative to 100 parts by mass of all the monomers.

[0105] <Polymerization Temperature>

[0106] From the viewpoint of easy control of the reaction, the polymerization temperature is ideally in the range of 0 to 55°C. From the viewpoint of conducting the polymerization reaction more smoothly and safely, the lower limit of the polymerization temperature is ideally above 5°C, the upper limit is ideally below 45°C, more preferably below 40°C, and even more preferably below 35°C.

[0107] <Polymerization Rate>

[0108] In the emulsification polymerization step, polymerization is stopped by adding a polymerization terminator when the monomer reaches the desired polymerization rate, thus obtaining the polymerized liquid after the reaction is complete. The polymerization rate at the end of polymerization can be less than 100%, and can be in the range of 60% to 95%.

[0109] <Polymerization Terminator>

[0110] As polymerization terminators, thiodiphenylamine, 4-tert-butylcatechol, 2,2'-methylenebis-4-methyl-6-tert-butylphenol, etc. can be used.

[0111] Removal of unreacted monomers

[0112] Chloroprene-based polymer latexes can be obtained by removing unreacted monomers from the polymerization solution after emulsification polymerization using common methods such as steam stripping and vacuum heating evaporation.

[0113] 2.1.2 Coagulant Composition Addition and Mixing Steps

[0114] The method for manufacturing a chloroprene-based polymer composition includes a coagulant composition addition and mixing step. In the coagulant composition addition and mixing step, a coagulant composition is added to and mixed with a chloroprene-based polymer latex containing a chloroprene-based polymer and water, causing the chloroprene-based polymer composition containing the chloroprene-based polymer to precipitate. The coagulant composition contains at least one main group element from the third and fourth periods and an acid. The pH of the coagulant composition is 0.7 to 2.5. The amount of coagulant composition added is 50 to 200 parts by weight relative to 100 parts by weight of the chloroprene-based polymer latex.

[0115] In the coagulant composition addition 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 above method, so that the chloroprene polymer composition containing the chloroprene polymer precipitates out.

[0116] The pH of the coagulant composition is 0.7 to 2.5. The pH of the coagulant composition is, 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, 2.5, or any value between two of the values ​​exemplified herein.

[0117] The coagulant composition contains at least one main group element from the third and fourth periods. This at least one main group element from the third and fourth periods includes at least one selected from calcium, magnesium, and aluminum, preferably calcium. As an example, the coagulant composition can be prepared by adding at least one of the chlorides, sulfates, nitrates, and phosphates of calcium, magnesium, and aluminum; specifically, it 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 third and fourth period main group element added relative to 100 parts by mass of the 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, or may be within any range of the values ​​exemplified herein.

[0118] The coagulant composition contains an acid. The acid preferably comprises at least one acid selected from acetic acid, hydrochloric acid, sulfuric acid, and nitric acid, and more preferably at least one acid selected from hydrochloric acid and acetic acid. The amount of acid added relative to 100 parts by weight of the coagulant composition is not particularly limited, as long as it brings the pH to within the range described above, for example, 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 weight, or any range between the values ​​exemplified herein.

[0119] The amount of coagulant composition added relative to 100 parts by weight of chloroprene-based polymer latex is 50 to 200 parts by weight. The amount of 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 weight, or any range between the values ​​exemplified herein.

[0120] In the coagulant composition addition and mixing step, the coagulant composition can be added to the chloroprene polymer latex all at once, or it can be added in batches. As an example, in the coagulant composition addition and mixing step, the coagulant composition can be added to the chloroprene polymer latex all at once.

[0121] The chloroprene-based polymer latex and coagulant composition can be mixed in an extruder using a screw extruder. Preferably, the mixing conditions are appropriately adjusted to ensure thorough mixing of the chloroprene-based polymer latex and the coagulant.

[0122] By adjusting the conditions in the coagulant composition addition and mixing step as described above, the content of dehydroabsic acid C and the content of main group elements in the third and fourth periods of the obtained chloroprene polymer composition can be controlled within a preferred range, and the precipitation state of the chloroprene polymer composition can be kept good. For example, it can prevent the chloroprene polymer composition from precipitating insufficiently and flowing out in the form of chloroprene polymer latex.

[0123] 2.1.3 Separation Steps

[0124] A method for manufacturing a chloroprene-based polymer composition may include a separation step after the addition and mixing step of the coagulant composition. In the separation step, the chloroprene-based polymer composition containing the precipitated chloroprene-based polymer is separated from water. The separation can be performed using a dehydration device, such as a slot dehydrator, a strainer, or a dehydration roller, which are well-known dehydration devices.

[0125] 2.1.4 Washing Steps

[0126] 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.

[0127] During the washing process, more than one water wash can be performed, and more than two water washes are preferred.

[0128] The water supply amount for each wash, relative to 100 parts by weight of the chloroprene polymer composition, can be, for example, 50, 100, 150, 200, 250, or 300 parts by weight, or any value between those shown here. By adjusting the washing steps, the content of dehydroabietic acid (C) and the content of third- and fourth-period group elements in the resulting chloroprene polymer composition can be controlled within preferred ranges.

[0129] 2.1.5 Drying Steps

[0130] The method for manufacturing the chloroprene-based polymer composition may also include a drying step. In the drying step, water adhering to the chloroprene-based polymer composition is further removed by heating.

[0131] In the drying step, the ambient temperature is preferably set to below 130°C. Specifically, the temperature of the drying step is, for example, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, or 130°C, or any range between the values ​​exemplified here.

[0132] The drying time in the drying step is preferably within 10 minutes. The drying step preferably includes a high-temperature drying step at a temperature above 100°C and a low-temperature drying step at a temperature below 100°C. In the high-temperature drying step, the ambient temperature can be, for example, 100, 110, 120, or 130°C, or any range between the values ​​exemplified herein. The high-temperature drying step is preferably within 3 minutes. In the low-temperature drying step, the ambient temperature is specifically, for example, 30, 40, 50, 60, 70, 80, 90, or 100°C, or any range between the values ​​exemplified herein. The low-temperature drying step is preferably within 7 minutes.

[0133] 2.1.6 Other steps

[0134] The manufacturing method of the chloroprene-based polymer composition may also include a molding step, in which the chloroprene-based polymer composition is molded into a desired shape, such as a sheet or a chip, using known molding methods. As an example, in the case of molding into a chip shape, known methods such as side heat cutting or center heat cutting can be used.

[0135] In the above-mentioned method for manufacturing the chloroprene-based polymer composition, at least one of the following steps—the coagulant composition addition and mixing step, the separation step, the washing step, the drying step, and the molding step—can be carried out in an extruder. Preferably, two or more steps are carried out in an extruder, more preferably three or more steps are carried out in an extruder, and even more preferably all steps are carried out in an extruder, which improves the working environment. It should be noted that, for example, the molding step being carried out in an extruder also includes cases where a portion of the molding step is carried out in an extruder.

[0136] 2.2 Method for manufacturing the chloroprene-based polymer composition of the second embodiment

[0137] The method for manufacturing a chloroprene-based polymer composition according to a second embodiment of the present invention includes a first coagulant composition addition and mixing step, a second coagulant composition addition and mixing step, and a washing step. In the first coagulant composition addition and mixing step, the first coagulant composition is added to a chloroprene-based polymer latex containing a chloroprene-based polymer and water and mixed to obtain a mixture 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 relative to 100 parts by weight of the chloroprene-based polymer latex is 25 to 100 parts by weight. In the second coagulant composition addition and mixing step, the second coagulant composition is added to the mixture after the first coagulant composition is added and mixed to precipitate the chloroprene polymer composition containing the chloroprene polymer. The second coagulant composition contains at least one main group element from the third and fourth periods. The amount of the second coagulant composition added is 25 to 100 parts by weight relative to 100 parts by weight 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 and second coagulant compositions adhering to the chloroprene polymer composition.

[0138] Hereinafter, the second embodiment will be described with a focus on its differences from the manufacturing method of the first embodiment.

[0139] 2.2.1 Emulsification Polymerization Step

[0140] The emulsification polymerization step can be the same as the manufacturing method of the first embodiment.

[0141] 2.2.2 First coagulant composition addition and mixing step

[0142] The method for manufacturing a chloroprene-based polymer composition includes a first coagulant composition addition and mixing step. In the first coagulant composition addition and mixing step, the first coagulant composition is added to a chloroprene-based polymer latex containing a chloroprene-based polymer and water and mixed to obtain a mixture after the addition of the first coagulant composition. The first coagulant composition contains an acid and has a pH of 0.7 to 4.0. The amount of the first coagulant composition added is 25 to 100 parts by weight relative to 100 parts by weight of the chloroprene-based polymer latex.

[0143] In the first coagulant composition addition and mixing step, for example, the first coagulant composition is added to the chloroprene polymer latex containing chloroprene polymer and water obtained by the above method and mixed to obtain a mixture after the addition of the first coagulant composition.

[0144] 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, or may be within any two of the values ​​exemplified herein.

[0145] The first coagulant composition contains an acid. The acid preferably comprises at least one acid selected from acetic acid, hydrochloric acid, sulfuric acid, and nitric acid, and more preferably at least one acid selected from hydrochloric acid and acetic acid. The amount of acid added relative to 100 parts by weight of the coagulant composition is not particularly limited, as long as it brings the pH to within the range described above, for example, 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 weight, or any range between the values ​​exemplified herein.

[0146] The amount of the first coagulant composition added relative to 100 parts by weight of the chloroprene-based polymer latex is 25 to 100 parts by weight. The amount of the first coagulant composition added is, for example, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 parts by weight, or may be within any range between the values ​​exemplified herein.

[0147] In the first coagulant composition addition and mixing step, the first coagulant composition can be added to the chloroprene polymer latex all at once, or it can be added in batches. As an example, in the first coagulant composition addition and mixing step, the coagulant composition can be added to the chloroprene polymer latex all at once.

[0148] The chloroprene-based polymer latex and the first coagulant composition can be mixed in an extruder using a screw extruder. Preferably, the mixing conditions are appropriately adjusted to ensure thorough mixing of the chloroprene-based polymer latex and the first coagulant composition. As mentioned earlier, the first coagulant composition contains an acid. The resulting mixture after adding the first coagulant composition to the chloroprene-based polymer latex preferably has a pH lower than that of the chloroprene-based polymer latex, and the mixture generally has a uniform pH. As an example, in the first coagulant composition addition and mixing step, it is preferable to mix for at least 3 seconds after all the first coagulant composition has been added, and then proceed to the second coagulant composition addition and mixing step. The mixing time can be 3 seconds or more, or 5 seconds or more, 10 seconds or more, 30 seconds or more, or 60 seconds or more.

[0149] 2.2.3 Second coagulant composition addition and mixing step

[0150] In the second coagulant composition addition and mixing step, the second coagulant composition is added to the mixture after the first coagulant composition is added and mixed, so that the chloroprene polymer composition containing the chloroprene polymer is precipitated. The second coagulant composition contains at least one main group element from the third and fourth periods. 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.

[0151] In the second coagulant composition addition and mixing step, for example, the second coagulant composition is added to and mixed with a chloroprene polymer latex containing a chloroprene polymer and water obtained by the above method, so that the chloroprene polymer composition containing the chloroprene polymer precipitates out.

[0152] The second coagulant composition contains at least one main group element from the third and fourth periods. This at least one main group element may include at least one selected from calcium, magnesium, and aluminum, preferably calcium. As an example, the second coagulant composition can be prepared by adding at least one of the chlorides, sulfates, nitrates, and phosphates of calcium, magnesium, and aluminum; specifically, it 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 third and fourth period main group element added relative to 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, or may be within any range of the values ​​exemplified herein.

[0153] There is no particular limitation on the pH of the second coagulant composition. The pH of the second coagulant composition may be, 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, or 8.0, or may be within any range of the values ​​exemplified herein.

[0154] The amount of the second coagulant composition added relative to 100 parts by weight of the chloroprene-based polymer latex is 25 to 100 parts by weight. The amount of the second coagulant composition added is, for example, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 parts by weight, or may be within any range between the values ​​exemplified herein.

[0155] In the second coagulant composition addition and mixing step, the second coagulant composition can be added to the mixture after the first coagulant composition has been added all at once, or it can be added in batches. As an example, in the second coagulant composition addition and mixing step, the coagulant composition can be added to the mixture after the first coagulant composition has been added all at once.

[0156] The chloroprene-based polymer latex and the second coagulant composition can be mixed in an extruder using a screw extruder. Preferably, the mixing conditions are appropriately adjusted to ensure that the mixture after the addition of the first coagulant composition is fully mixed with the second coagulant composition.

[0157] By adjusting the conditions in the first and second coagulant composition addition and mixing steps as described above, the content of dehydroabsic acid C and the content of main group elements in the third and fourth periods of the obtained chloroprene polymer composition can be controlled within a preferred range, and the precipitation state of the chloroprene polymer composition can be kept good. For example, it can prevent the chloroprene polymer composition from precipitating insufficiently and flowing out in the form of chloroprene polymer latex.

[0158] 2.2.4 Separation step, washing step, drying step, and other steps

[0159] The separation, washing, drying, and other steps can be the same as the manufacturing method of the first embodiment.

[0160] In the above-described method for manufacturing the chloroprene-based polymer composition, at least one of the following steps—the first coagulant composition addition and mixing step, the second coagulant composition addition 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 are performed in an extruder, more preferably three or more steps are performed in an extruder, and even more preferably all steps are performed in an extruder, which improves the working environment. It should be noted that, for example, performing the molding step in an extruder also includes cases where a portion of the molding step is performed in an extruder.

[0161] 3. Adhesive composition

[0162] An adhesive composition according to one embodiment of the present invention comprises the above-described chloroprene-based polymer composition. An adhesive composition according to one embodiment of the present invention may also comprise a solution obtained by dissolving the above-described chloroprene-based polymer composition in an organic solvent.

[0163] There are no restrictions on the types of organic solvents mentioned above. For example, toluene, xylene, acetone, methyl ethyl ketone, n-hexane, cyclohexane, methylcyclohexane, cyclopentane, isopropyl acetate, or ethyl acetate can be used.

[0164] The organic solvent can 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 (these substances can cause Sick House Syndrome). More preferably, the above-mentioned chloroprene-based polymer rubber is dissolved using only a mixture of solvents with poor solubility (poor solubility for chloroprene-based polymer rubbers on its own). For example, an organic solvent with a cyclohexane:ethyl acetate ratio of 1:1 (mass ratio) can be used.

[0165] The amount of organic solvent used can be adjusted appropriately according to the application and type of the adhesive, and there is no particular limitation. If the viscosity of the adhesive composition is adjusted to 3500 to 4500 mPa·s, the balance between the heat resistance and initial adhesion of the adhesive becomes good, and therefore it is preferred.

[0166] In addition to solvents, adhesive compositions may also contain metal oxides, tackifying resins, and anti-aging agents. Adding these additives to the adhesive composition can improve the initial bond strength, normal bond strength, and sprayability of the resulting adhesive composition.

[0167] As metal oxides, zinc oxide (zinc oxide), aluminum oxide, titanium oxide, or magnesium oxide can be used, for example.

[0168] For example, phenolic resin, rosin resin, coumarone resin, petroleum resin, etc. can be used as tackifying resins.

[0169] As anti-aging agents, for example, 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetratetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N,N'-hexane-1,6-diylbis-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and N,N'-hexane-1,6-diylbis-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate can be used. 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-tert-butyl-a,a',a''-(trimethylbenzene-2,4,6-triyl)tri-p-cresol, ethylene bis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], tetraethyl thiuram disulfide, tetrabutyl thiuram disulfide, tetramethyl thiuram monosulfide, dibutylhydroxytoluene, etc.

[0170] Depending on the desired physical properties, the adhesive composition may further include formaldehyde scavengers or fillers, etc.

[0171] Examples of formaldehyde scavengers that can be used include pyrrolidine, piperidine, piperazine, morpholine, melamine, dicyandiamide, urea, ethylene urea, 4,5-dimethoxyethylene urea, propane urea, 5-methylpropane urea, 5-hydroxypropane urea, 5-methoxypropane urea, parabanic acid, hydrazinobenzothiazole, aminourea, and thioaminourea. Formaldehyde scavengers can capture formaldehyde, a harmful volatile substance.

[0172] As fillers, talc, calcium carbonate, clay, montmorillonite, silica, hydrotalcite, or mica can be used.

[0173] In addition, to improve light resistance, UV absorbers such as benzotriazole and light stabilizers such as hindered amines can be added to the adhesive composition.

[0174] The adhesive composition of one embodiment of the present invention may further comprise 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.

[0175] There are no particular limitations on the manufacturing method of the adhesive composition; any known machinery or apparatus may be used. A common method for manufacturing the adhesive composition is to dissolve alkylphenol resin or magnesium oxide in an organic solvent, allow it to stand at room temperature for 10–20 hours, and then dissolve the diced chloroprene-based polymer rubber, metal oxides, anti-aging agents, etc.

[0176] The adhesive composition of one embodiment of the present invention can be used as an adhesive or a raw material for an adhesive. For example, an adhesive can be obtained by further adding other additives to the above adhesive composition, or by mixing the above adhesive composition with other adhesive compositions. The adhesive is suitable for bonding and adhering similar or dissimilar materials such as paper, wood, cloth, leather, knitted fabrics, artificial leather, rubber, plastics, foams, ceramics, glass, mortar, cementitious materials, ceramics, and metals.

[0177] [Example]

[0178] The present invention will now be described in more detail based on embodiments, but the present invention should not be construed as being limited to these embodiments.

[0179] (Example 1)

[0180] <Manufacturing of Chloroprene-based Polymer Latex>

[0181] Using a 5-liter reactor under nitrogen atmosphere, 3.3 parts by mass of disproportionated tall oil rosinate sodium salt 3R-70N (manufactured by Arakawa Chemical Co., Ltd.), 0.5 parts by mass of disproportionated tall oil rosinate sodium salt 6R-70N (manufactured by Harima Chemicals), 0.4 parts by mass of sodium salt of naphthalenesulfonic acid and formaldehyde condensate (trade name DEMOL N: manufactured by Kao), 0.5 parts by mass of sodium bisulfite, 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 added to this solution and emulsified. Potassium persulfate was added as a polymerization initiator, and polymerization was carried out at a polymerization temperature of 10°C under a nitrogen atmosphere. When the polymerization conversion reached 72% or higher, phenothiazine emulsion was added as a polymerization terminator to stop the reaction. Unreacted monomers were removed under reduced pressure to obtain a chloroprene-based polymer latex with a solid content of 40%.

[0182] <Preparation of Chloroprene-based Polymer Compositions>

[0183] (Addition and mixing steps of the coagulant composition)

[0184] A chloroprene-based polymer latex and a coagulant composition are fed into a twin-screw extruder and mixed using the screws to precipitate the chloroprene-based polymer composition. The amount of coagulant composition added is 67 parts by weight relative to 100 parts by weight of the chloroprene-based polymer latex. Here, the coagulant composition contains 1 part by weight of CaCl2 and 0.365 parts by weight of hydrochloric acid relative to 100 parts by weight of the coagulant composition, and the pH is 1.00.

[0185] (Washing steps, etc.)

[0186] Subsequently, dehydration is performed using a slot dehydrator to remove at least a portion of the coagulant composition and water adhering to the chloroprene polymer composition. After dehydration, the obtained chloroprene polymer composition is washed with water to further remove at least a portion of the coagulant composition adhering to the chloroprene polymer composition. Then, it is dried at 120°C until the moisture content is below 10% by mass to obtain the chloroprene polymer composition. The obtained chloroprene polymer rubber is then cut into blocks using a side-heat-cut molding step. The coagulant composition addition and mixing step, washing step, drying step, and molding step are all performed in a twin-screw extruder.

[0187] (Examples 2-4, Comparative Examples 1-3, 6, 7, 10)

[0188] Except for changing the composition and amount of the coagulant composition and the washing conditions, a chloroprene-based polymer composition was obtained in the same manner as in Example 1.

[0189] (Example 5)

[0190] <Manufacturing of Chloroprene-based Polymer Latex>

[0191] Chloroprene-based polymer latex was obtained in the same manner as in Example 1.

[0192] <Preparation of Chloroprene-based Polymer Compositions>

[0193] (First coagulant composition addition and mixing step)

[0194] A chloroprene-based polymer latex and a first coagulant composition are fed into a twin-screw extruder and mixed using the screws to obtain a mixture after the addition of the first coagulant composition. The amount of the first coagulant composition added is 67 parts by weight relative to 100 parts by weight of the chloroprene-based polymer latex. Here, the coagulant composition contains 0.6 parts by weight of acetic acid relative to 100 parts by weight of the coagulant composition, and the pH is 2.78.

[0195] (Second coagulant composition addition and mixing step)

[0196] After adding and mixing the first coagulant composition for at least 3 seconds, the second coagulant composition is further fed into a twin-screw extruder, where it is mixed using the screws to precipitate the chloroprene polymer composition. The amount of the second coagulant composition added is 67 parts by weight relative to 100 parts by weight of the chloroprene polymer latex. Here, the coagulant composition contains 1 part by weight of CaCl2 relative to 100 parts by weight of the coagulant composition, and the pH is 7.00.

[0197] (Washing steps, etc.)

[0198] Subsequently, dehydration is performed using a slot dehydrator to remove at least a portion of the coagulant composition and water adhering to the chloroprene polymer composition. After dehydration, the obtained chloroprene polymer composition is washed with water to further remove at least a portion of the coagulant composition adhering to the chloroprene polymer composition. The water washing is performed twice, with 150 parts by weight of water used relative to 100 parts by weight of the chloroprene polymer composition in each step. Afterwards, it is dried at 120°C until the moisture content is below 10% by weight to obtain the chloroprene polymer composition. The obtained chloroprene polymer rubber is then cut into blocks using a side-heat-cut molding step. The above coagulant composition addition and mixing step, washing step, drying step, and molding step are all carried out in a twin-screw extruder.

[0199] (Examples 6 and 7, Comparative Examples 4, 5, 8, and 9)

[0200] Except for changes to the composition and amount of the first and second coagulant compositions, and the washing conditions, a chloroprene-based polymer composition was obtained in the same manner as in Example 5.

[0201] The precipitation state during manufacturing is evaluated as follows.

[0202] <Precipitation Status>

[0203] The effluent from the slot dehydrator was evaluated according to the following evaluation criteria.

[0204] ○: The effluent is less turbid.

[0205] ×: The outflow is turbid.

[0206] It should be noted that turbidity in the effluent indicates insufficient precipitation (coagulation), resulting in the outflow of chloroprene-based polymer latex. In Comparative Examples 6-9, chloroprene-based polymer latex flowed out, making it difficult to obtain chloroprene-based polymer compositions.

[0207] The obtained chloroprene-based polymer compositions were evaluated as follows. It should be noted that the water content of all obtained chloroprene-based polymer compositions was below 3% by mass.

[0208] <Content of dehydroabietic acid in the form of dehydroabirate C>

[0209] The content C of dehydroabietic acid in the form of dehydroabirate relative to 100 parts by mass of the chloroprene polymer composition was determined by the following method.

[0210] <Determination Method>

[0211] 1. Vacuum dry 3g±0.03g of chloroprene polymer composition to obtain a dried chloroprene polymer composition with a moisture content of less than 0.5% by mass.

[0212] 2. Cut the dried chloroprene polymer composition into cubes with a side length of 2-3 mm and place them in a round-bottom flask. Add 35 mL of ETA (ethanol:toluene = 70:30 vol%) as specified in JIS K 6229. Heat and extract at 90 °C for 1 hour. Transfer only the resulting extract to a 100 mL volumetric flask.

[0213] 3. Add 35 mL of ETA to the flask containing the dried chloroprene polymer composition again, heat and extract at 90°C for 1 hour, and transfer only the resulting extract to the 100 mL volumetric flask mentioned above.

[0214] 4. When the above extract in the 100mL volumetric flask reaches 23°C, dilute the extract to 100mL with ETA to obtain the analytical solution before acid treatment.

[0215] 5. Analyze 50 mL of the solution before acid treatment using gas chromatography to quantify dehydroabietic acid and calculate the dehydroabietic acid content A relative to 100 parts by mass of the chloroprene polymer composition before acid treatment. The quantification of dehydroabietic acid is based on a calibration curve obtained by measuring dehydroabietic acid ETA solutions with known dehydroabietic acid content.

[0216] 6. Dry 50 mL of the pre-acid-treated analytical solution, add a small amount (e.g., 5-10 mL) of ETA and apply ultrasonic vibration to dissolve it, add 1 mol / L hydrochloric acid to adjust the pH to 1 and dry it, dissolve it in methanol and make up to 50 mL to obtain the post-acid-treated analytical solution.

[0217] 7. The acid-treated analytical solution was analyzed using gas chromatography to quantify dehydroabietic acid and calculate the dehydroabietic acid content B relative to 100 parts by mass of the chloroprene polymer composition after acid treatment. The quantification of dehydroabietic acid was based on a calibration curve obtained by measuring a methanol solution of dehydroabietic acid with a known content of dehydroabietic acid.

[0218] 8. Subtract the content of dehydroabietic acid before acid treatment (A) from the content of dehydroabietic acid after acid treatment (B) to calculate the content of dehydroabietic acid in the form of dehydroabiate (C).

[0219] <Content of main group elements relative to 100 parts by mass of the chloroprene-based polymer composition>

[0220] The content of main group elements relative to 100 parts by mass of the chloroprene polymer composition was determined by the following method.

[0221] First, the chloroprene-based polymer composition was vacuum-dried for 24 hours to reduce its moisture content to below 0.5% by mass, and then cut into approximately cubes with sides of about 5 mm. The mass of the cut sample was measured and recorded as the "mass of the sample used for analysis (g)". The cut 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 digested using a microwave digestion device to obtain a digest. The digest was washed into a 25 mL glass colorimetric tube and diluted to 25 mL with ultrapure water to obtain the analytical sample. Using the analytical sample, quantitative analysis was performed using an inductively coupled plasma optical emission spectrometer (ICP-OES) with the wavelength of the target element set. The "concentration of the analytical sample (mg / L)" was determined from a calibration curve prepared using a metal standard solution. The amount of each metal element contained in 1 kg of the sample (mg / kg) is determined from the concentration of the sample used for analysis (mg / L) and the mass of the sample used for analysis (g), thereby determining the content of the main group elements relative to 100 parts by mass of the chloroprene polymer composition.

[0222] The amount of metal contained in the sample (mg / kg) = concentration of the sample used for analysis (mg / L) × 25 ÷ mass of the sample used for analysis (g)

[0223] The analysis conditions for ICP-OES are shown below.

[0224] Device: 5800VDV, manufactured by Agilent

[0225] Points awarded for: 30 seconds / 3 attempts

[0226] Preparation of a 10% by mass toluene solution of a chloroprene-based polymer composition

[0227] Toluene was added to the obtained chloroprene-based polymer composition to prepare a 10% by mass toluene solution of the chloroprene-based polymer composition, and the following evaluation was performed. It should be noted that the chloroprene-based polymer composition was dissolved in toluene after being vacuum dried until the moisture content was below 0.1% by mass.

[0228] (Turbidity)

[0229] 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 evaluation criteria.

[0230] ◎: Almost transparent

[0231] ○: Slightly cloudy

[0232] △: Turbid

[0233] ×: Obvious turbidity

[0234] (Resistance to delamination)

[0235] A 10% toluene solution of the chloroprene polymer composition was placed in a transparent 225 mL glass bottle. The appearance was observed after standing at 23°C for 5 days, and the resistance to stratification separation was determined according to the following evaluation criteria. It should be noted that the "mist" is a component insoluble in toluene and water, and is considered to contain resin acid salts, such as calcium dehydroabirate.

[0236] Yes: Settling of the fog-like substance was observed.

[0237] None: No sedimentation of the fog was observed.

[0238] (Yellowishness)

[0239] A 10% toluene solution of the chloroprene polymer composition was placed in a transparent 225 mL glass bottle, and the yellowing was visually assessed according to the following evaluation criteria. It should be noted that the cause of the discoloration is unclear, but it may be due to the structure of the chloroprene polymer.

[0240] ◎: Almost colorless

[0241] ○: Light yellowish-green

[0242] ×: Yellow-green to deep yellow-green

[0243] <Preparation of Adhesive Compositions>

[0244] To prepare an adhesive composition, 2 parts by weight of BHT (butylated hydroxytoluene), 6 parts by weight of MgO (Kyowa Chemical Industry Co., Ltd., Kyowamag 150), 1 part by weight of ZnO (Sakai Chemical Industry Co., Ltd., Zinc Oxide No. 2), and 50 parts by weight of alkylphenol resin (Arakawa Chemical Industry Co., Ltd., Tamanol 526) were added relative to 100 parts by weight of the chloroprene polymer composition. A solvent of cyclohexane:methyl ethyl ketone (MEK) in a 1:1 mass ratio was further added to achieve a solution viscosity of 4000 ± 400 mPa·s. It should be noted that the chloroprene polymer composition was vacuum-dried until the moisture content was below 0.1% by weight before being used to prepare the adhesive composition.

[0245] (Storage stability)

[0246] The time until delamination occurs when the adhesive composition is left to stand at 23°C is evaluated according to the following evaluation criteria.

[0247] ◎: No layer separation was observed even after more than 7 days.

[0248] ○: Layer separation was observed within 4 to 7 days.

[0249] △: Layer separation was observed within 2 to 4 days.

[0250] ×: Layer separation was observed within 2 days.

[0251] [Table 1]

[0252]

[0253] [Table 2]

[0254]

Claims

1. A chloroprene-based polymer composition comprising a chloroprene-based polymer, The moisture content of the chloroprene-based polymer composition is less than 10% by mass. The content C of dehydroabietic acid in the form of dehydroabirate, relative to 100 parts by mass of the chloroprene polymer composition, as determined by the following method, is 0.075 to 1.600 parts by mass. <Determination Method> 1. Vacuum dry 3g±0.03g of the chloroprene polymer composition to obtain a dried chloroprene polymer composition with a moisture content of less than 0.5% by mass; 2. Cut the dried chloroprene polymer composition into cubes with a side length of 2-3 mm and place them in a flask. Add 35 mL of ETA (ethanol:toluene = 70:30 vol%) as specified in JIS K 6229, heat and extract at 90 °C for 1 hour, and transfer only the resulting extract to a 100 mL volumetric flask.

3. Add 35 mL of ETA to the flask containing the dried chloroprene polymer composition again, heat and extract at 90°C for 1 hour, and transfer only the resulting extract to the 100 mL volumetric flask.

4. When the extract in the 100mL volumetric flask reaches 23°C, dilute the extract to 100mL with ETA to obtain an analytical solution before acid treatment; 5. 50 mL of the solution used for analysis before acid treatment is analyzed by gas chromatography to quantify dehydroabietic acid and calculate the content A of dehydroabietic acid before acid treatment relative to 100 parts by mass of the chloroprene polymer composition. The quantification of dehydroabietic acid is based on a calibration curve obtained by measuring the content of dehydroabietic acid in the ETA solution of dehydroabietic acid.

6. Dry 50 mL of the pre-acid-treated analytical solution, add a small amount of ETA and apply ultrasonic vibration to dissolve it, add 1 mol / L hydrochloric acid to adjust the pH to 1 and then dry it, dissolve it with methanol and make up to 50 mL to obtain the post-acid-treated analytical solution.

7. The acid-treated analytical solution is analyzed using a gas chromatograph to quantify the dehydroabietic acid and calculate the content B of the acid-treated dehydroabietic acid relative to 100 parts by mass of the chloroprene polymer composition. The quantification of dehydroabietic acid is based on a calibration curve obtained by measuring the content of dehydroabietic acid in a methanol solution of dehydroabietic acid.

8. Subtract the content of dehydroabietic acid before acid treatment (A) from the content of dehydroabietic acid after acid treatment (B) to calculate the content of dehydroabietic acid in the form of dehydroabiate (C).

2. The chloroprene-based polymer composition according to claim 1, wherein, It contains at least one main group element from the third and fourth period main group elements. The content of the main group element is 0.005 to 0.100 parts by mass relative to 100 parts by mass of the chloroprene polymer composition.

3. The chloroprene-based polymer composition according to claim 2, wherein, The main group elements include at least one selected from calcium, magnesium, and aluminum.

4. The chloroprene-based polymer composition according to claim 1 or 2, used in adhesives containing organic solvents.

5. A method for manufacturing a chloroprene-based polymer composition, comprising a coagulant composition addition and mixing step and a washing step. In the coagulant composition addition and mixing step, the coagulant composition is added to and mixed with a chloroprene-based polymer latex containing a chloroprene-based polymer and water, causing the chloroprene-based polymer composition containing the chloroprene-based polymer to precipitate. The coagulant composition contains at least one main group element from the third and fourth periods and an acid. The pH of the coagulant composition is 0.7–2.

5. The amount of the coagulant composition added is 50 to 200 parts by weight relative to 100 parts by weight of the chloroprene-based 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.

6. A method for manufacturing a chloroprene-based polymer composition, comprising a first coagulant composition addition and mixing step, a second coagulant composition addition and mixing step, and a washing step. In the first coagulant composition addition and mixing step, the first coagulant composition is added to a chloroprene-based polymer latex containing a chloroprene-based polymer and water and mixed to obtain a mixture after the addition of the first coagulant composition. The first coagulant composition contains acid. The pH of the first coagulant composition is 0.7–4.

0. The amount of the first coagulant composition added is 25 to 100 parts by weight relative to 100 parts by weight of the chloroprene-based polymer latex. In the second coagulant composition addition and mixing step, the second coagulant composition is added to the mixture after the first coagulant composition has been added and mixed, causing the chloroprene-based polymer composition containing the chloroprene-based polymer to precipitate. The second coagulant composition contains at least one main group element from the third and fourth periods. The amount of the second coagulant composition added is 25 to 100 parts by weight relative to 100 parts by weight of the chloroprene-based 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.

7. The method for manufacturing the chloroprene-based polymer composition according to claim 5 or 6, wherein, The acid includes at least one acid selected from acetic acid, hydrochloric acid, sulfuric acid, and nitric acid.

8. The method for manufacturing the chloroprene-based polymer composition according to claim 5 or 6, wherein, At least some steps are performed inside the extruder.

9. An adhesive composition comprising the chloroprene-based polymer composition of claim 1 or 2.

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