Chip, method for producing chip, and adhesive composition

Abstract

To provide a chip excellent in anti-blocking property, soluble in an organic solvent in a shorter time, excellent in brush coating property and anti-layer separation property, and capable of obtaining a colorless adhesive composition, a method for producing the chip, and an adhesive composition excellent in brush coating property and anti-layer separation property, and less in coloration.SOLUTION: A chip for an adhesive composition includes a chloroprene polymer rubber, wherein a temperature near the center of the chip after 60 sec. from holding the chip heated to 140°C in a room of 23°C is 130°C or lower, and a time necessary for AX to surpass A0+20 is shorter than 500 min. when a type A durometer hardness measured in accordance with JISK6253-3 after being left for one hour under an environment of 23°C by forming the chip into a sheet of a thickness of 6 mm by press molding at 70°C, and taking out from a metal mold is A0, and a type A durometer hardness measured after X min. from the input by putting a sheet of a thickness of 6 mm into a constant temperature bath of -10°C is AX.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a chip containing a chloroprene-based polymer rubber, a method for producing the chip, and an adhesive composition.

Background Art

[0002] Chloroprene-based polymers are substances excellent in heat resistance, weather resistance, ozone resistance, chemical resistance, flame retardancy (self-extinguishing property), etc., and have many excellent properties even when compared with natural rubber and other synthetic resins. The chloroprene-based polymer having such well-balanced physical properties as a whole is used in various applications, and a typical example thereof is an application as an adhesive.

[0003] An adhesive containing a chloroprene-based polymer rubber is obtained by dissolving a chloroprene-based polymer rubber in an organic solvent such as toluene or acetone, and dissolving and / or dispersing a tackifier resin and a metal oxide, etc. as necessary, and cures and adheres by volatilization of the organic solvent. Since the adhesive containing a chloroprene-based polymer rubber is excellent in adhesive properties such as initial adhesion strength, it is used in a wide range of fields such as woodworking, furniture, and vehicles (see, for example, Patent Documents 1 and 2).

[0004] In recent years, it has been desired to convert the solvent used in solvent-based adhesives to a non-aromatic solvent. However, with this conversion, so-called layer separation, in which components soluble in the organic solvent and components insoluble therein are separated when the solvent-based adhesive is stored, is likely to occur. As a technique related to a composition containing a chloroprene-based polymer excellent in layer separation stability, Patent Document 3 discloses a technique of copolymerizing a specific ethylenically unsaturated sulfonic acid or its salt within a specific range when polymerizing chloroprene. Further, Patent Document 4 discloses a chloroprene rubber composition containing at least one kind of a sulfonic acid compound having a specific structure in an amount of 0.005 to 10 parts by mass with respect to 100 parts by mass of chloroprene rubber.

[0005] Furthermore, Patent Document 5 discloses an adhesive composition obtained by dissolving, in an organic solvent, an unmodified chloroprene-based polymer A obtained by polymerizing chloroprene alone or copolymerizing two or more monomers including chloroprene, and a sulfur-modified chloroprene-based polymer B obtained by polymerizing chloroprene alone or copolymerizing two or more monomers including chloroprene in the presence of sulfur.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, conventional chloroprene-based polymer rubbers have the problem that when stored under pressure in a high-temperature environment, they adhere to each other (blocking) and the handling property deteriorates, and it takes a long time to completely dissolve chips or sheets containing the chloroprene-based polymer rubber in an organic solvent in order to obtain an adhesive composition. In addition, there is room for improvement in the layer separation resistance and brushability of the obtained adhesive composition, and furthermore, there is a problem that the adhesive composition is colored. It has been difficult to solve these problems simultaneously.

[0008] The present invention has been made in view of such circumstances, and it is possible to obtain a chip that is excellent in blocking resistance, dissolves in an organic solvent in a short time, is excellent in brushability and layer separation resistance, and has an adhesive composition without coloring, a method for manufacturing the chip, and an adhesive composition that is excellent in brushability and layer separation resistance and has little coloring.

Means for Solving the Problems

[0009] According to the present invention, there is provided a chip for an adhesive composition containing a chloroprene-based polymer rubber, when the temperature near the center of the chip after holding the chip heated to 140°C in a room at 23°C for 60 seconds is 130°C or lower, the chip is press-molded at 70°C into a sheet with a thickness of 6 mm, taken out of the mold, and allowed to stand in a 23°C environment for 1 hour, and the type A durometer hardness measured based on JIS K 6253-3 is defined as A0, when the sheet with a thickness of 6 mm is put into a thermostat at -10°C and the type A durometer hardness after X minutes from the input is defined as A X when A X exceeds A0 + 20, a chip is provided in which the time required is less than 500 minutes.

[0010] As a result of intensive studies, the present inventor has found that in the production of a chip containing a chloroprene-based polymer rubber, by highly controlling the conditions during production to obtain a chip with less heat storage, and setting the time (crystallization time) required for the hardness of the chip measured under specific conditions to change by a specified amount within a specific range, a chip that is excellent in blocking resistance and dissolves in an organic solvent in a short time can be obtained, and also a chip that can provide an adhesive composition excellent in brushability, layer separation resistance, and having little coloring, thus leading to the completion of the present invention. According to another aspect of the present invention, there is provided a method for manufacturing the chip described above, comprising a separation step of separating the chloroprene-based polymer rubber from the chloroprene-based polymer latex by adding a coagulant to the chloroprene-based polymer latex containing the chloroprene-based polymer rubber to obtain a composition containing the chloroprene-based polymer rubber, and a molding step of molding the composition containing the chloroprene-based polymer rubber with an extruder to obtain a chip containing the chloroprene-based polymer rubber. In the molding step, the temperature of the chip containing the chloroprene-based polymer rubber immediately after discharge is less than 150°C. According to another aspect of the present invention, there is provided an adhesive composition containing a solution in which the chip described above is dissolved in an organic solvent.

[0011] Hereinafter, various embodiments of the present invention will be exemplified. The embodiments shown below can be combined with each other. (1) A chip for an adhesive composition containing a chloroprene-based polymer rubber, wherein the temperature near the center of the chip after holding the chip heated to 140°C in a room at 23°C for 60 seconds is 130°C or less. The chip is press-molded at 70°C into a sheet with a thickness of 6 mm, taken out of the mold, allowed to stand in a 23°C environment for 1 hour, and the type A durometer hardness measured based on JIS K6253-3 is defined as A0. The sheet with a thickness of 6 mm is put into a thermostatic bath at -10°C, and when the type A durometer hardness X minutes after the input is defined as A X the time required for A X to exceed A0 + 20 is less than 500 minutes. (2) Dissolve the chip in toluene to obtain a toluene solution of 10% by mass of the chloroprene-based polymer rubber. Immerse a glass tube with an inner diameter of 6 mm and an outer diameter of 8 mm 30 mm into the toluene solution of 10% by mass of the chloroprene-based polymer rubber adjusted to 20°C. When the glass tube is rotated at 2000 rpm for 30 seconds, the lowest liquid level height outside the glass tube is defined as the lowest liquid level height H0 outside the glass tube, and the highest liquid level height inside the glass tube is defined as the highest liquid level height H1 inside the glass tube. The chip according to (1), wherein the difference between the lowest liquid level height H0 outside the glass tube and the highest liquid level height H1 inside the glass tube is 10 mm or less. (3) The chip according to (1) or (2), wherein the absorbance at a wavelength of 440 nm of the toluene solution of 5% by mass of the chloroprene-based polymer rubber obtained by dissolving the chip in toluene is 0.30 or less. (4) A chip according to any one of (1) to (3), wherein when 100 g of the chip is dissolved in 400 g of an organic solvent having a cyclohexane:ethyl acetate = 1:1 (mass ratio) at 23°C, the time until the chip is dissolved in the organic solvent is 300 minutes or less. (5) The chip according to any one of (1) to (4), wherein the total content of alkaline earth metals, magnesium, aluminum, and zinc in the chip is 1 to 5000 mg / kg. (6) A method for producing the chip according to any one of (1) to (5), comprising a separation step of adding a coagulant to a chloroprene-based polymer latex containing the chloroprene-based polymer rubber to separate the chloroprene-based polymer rubber from the chloroprene-based polymer latex to obtain a composition containing the chloroprene-based polymer rubber, and a molding step of molding the composition containing the chloroprene-based polymer rubber with an extruder to obtain a chip containing the chloroprene-based polymer rubber. In the molding step, the temperature of the chip containing the chloroprene-based polymer rubber immediately after discharge is less than 150°C. (7) The production method according to (6), wherein in the molding step, the temperature of the chip containing the chloroprene-based polymer rubber 60 seconds after discharge is 130°C or less. The production method according to (8), (6) or (7), wherein in the molding step, the temperature of the die head is 120°C or lower, and the ratio Y / Z of the discharge rate Y (mm / min) of the chloroprene-based polymer rubber in the die head to the rotational speed Z (rpm) of the cutting blade for cutting the discharged chloroprene-based polymer rubber is 1 to 10. The production method according to any one of (9), (6) to (8), which does not have a step of water-cooling the chip after the molding step. The production method according to any one of (10), (6) to (9), further comprising a drying step of removing water from the composition containing the chloroprene-based polymer rubber separated in the separation step, and the atmospheric temperature in the drying step is 130°C or lower. The production method according to (11), (10), wherein the separation step, the drying step, and the molding step are performed in an extruder. An adhesive composition comprising a solution in which the chip according to any one of (1) to (5) is dissolved in an organic solvent. [Effect of the Invention]

[0012] According to the chip of the present invention, by making the chip have less heat storage and setting the time (crystallization time) required for the hardness of the chip measured under specific conditions to change by a specified amount within a specific range, it has excellent blocking resistance and can be dissolved in an organic solvent in a short time. Further, according to the chip, an adhesive composition excellent in brushability and layer separation resistance and with little coloring can be obtained. [Brief Description of the Drawings]

[0013]

Figure 1

[0014] Hereinafter, embodiments of the present invention will be exemplified and the present invention will be described in detail. The present invention is not limited in any way by these descriptions. The various characteristic matters of the embodiments of the present invention shown below can be combined with each other. Also, an invention can be established independently for each characteristic matter.

[0015] 1. Chloroprene-based polymer rubber The chip according to the present invention contains a chloroprene-based polymer rubber. Also, the chloroprene-based polymer rubber according to the present invention contains a chloroprene-based polymer. The chloroprene-based polymer is a homopolymer of 2-chloro-1,3-butadiene (hereinafter, chloroprene) or a copolymer of a chloroprene monomer and another monomer copolymerizable therewith.

[0016] Examples of monomers copolymerizable with the chloroprene monomer include 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, butadiene, isoprene, styrene, acrylonitrile, acrylic acid or its esters, methacrylic acid or its esters, and the like. These may be used alone or in combination of two or more. Although not particularly limited, from the viewpoint of maintaining the properties derived from chloroprene and adjusting the crystallinity of the polymer and setting the crystallization time within a specific range, the chloroprene-based polymer according to one embodiment of the present invention preferably has 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more of monomer units derived from the chloroprene monomer when the chloroprene-based polymer is 100% by mass.

[0017] 2. Chip containing chloroprene-based polymer rubber The chip according to the present invention contains a chloroprene-based polymer rubber. The chip according to the present invention has a heat storage property and a crystallization time within a specific range.

[0018] <Heat storage property> The chip according to the present invention is such that when a chip heated to 140°C is held in a 23°C room for 60 seconds, the temperature near the center of the chip is 130°C or lower. The chip according to the present invention is such that when a chip heated to 140°C is held in a 23°C room for 60 seconds, the temperature near the center of the chip is, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130°C, and may be within the range between any two of the values exemplified herein.

[0019] Here, the temperature near the center of the chip when a chip heated to 140°C is held in a 23°C room for 60 seconds can be measured by the following procedure. First, insert a K-type thermocouple into the chip so that the tip is near the center of the chip, and in that state, put the chip into an oven set at 150°C and heat it until the temperature near the center reaches 140°C. After the temperature near the center of the chip reaches 140°C, take out the chip into an environment of 23°C and measure the temperature near the center of the chip over time. During this period, it is preferable to hold it in the air so that the surface of the chip does not contact other objects. The temperature near the center of the chip 60 seconds after taking it out into the 23°C environment is defined as "the temperature near the center of the chip when a chip heated to 140°C is held in a 23°C room for 60 seconds". The tip of the thermocouple is preferably inserted into at least a point closer to the center of the chip than the chip surface, that is, into the inside of the chip. The distance between the tip of the thermocouple and the plane perpendicular to the thickness direction passing through the midpoint of the thickness is preferably 40% or less of the thickness, preferably 30% or less, and preferably 20% or less. The distance between the tip of the thermocouple and the plane parallel to the thickness direction including the minor axis is preferably 30% or less of the major axis, preferably 20% or less, and preferably 10% or less. The distance between the tip of the thermocouple and the plane parallel to the thickness direction including the major axis is preferably 30% or less of the minor axis, preferably 20% or less, and preferably 10% or less.

[0020] The above temperature can be adjusted by highly controlling the chip manufacturing conditions, particularly the types and amounts of ingredients during the production of chloroprene-based polymer latex, and the chip molding conditions, and controlling the components, specific heat, specific surface area, shape, etc. of the chip.

[0021] <Crystallization time> The chip according to the present invention is formed into a sheet with a thickness of 6 mm by press molding the chip at 70 °C, taken out of the mold and allowed to stand in a 23 °C environment for 1 hour, and then the type A durometer hardness measured based on JIS K 6253-3 is taken as A0. The sheet with a thickness of 6 mm is put into a constant temperature bath at -10 °C, and the type A durometer hardness after X minutes from the input is taken as A X When it is X the time required for A to exceed A0 + 20 is less than 500 minutes. X In this specification, the above "time required for A

[0022] to exceed A0 + 20" is also referred to as the crystallization time. The chip according to the present invention has a crystallization time of, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 450, 500 minutes, and may also be within the range between any two of the numerical values exemplified here. (Preparation of sheet for hardness measurement) First, a sheet for hardness measurement is prepared. As an example, the sheet can be prepared by the following procedure. Process the chip into a sheet shape with a thickness of 3 mm using an 8-inch diameter roll (surface temperature 30°C). Stack three of these sheets in a mold with a depth of 6 mm × length of 130 mm × width of 25 mm such that the longitudinal direction is the column alignment direction of the roll (the direction along the roll circumference when processed into a sheet shape by the roll), and press at 70°C for 20 minutes. The sample taken out of the mold is preferably left standing in a 23°C environment for 1 hour. Also, it is preferable to measure A0 described below immediately after the 1-hour standing. A0 is more preferably measured within 1 hour and preferably within 30 minutes after the end of at least 1 hour of standing time.

[0023] (Measurement of hardness before input into -10°C environment) For the sheet after standing, perform a hardness measurement using a Type A durometer based on JIS K 6253-3, and define the Type A durometer hardness at this time as A0. A0 indicates the hardness before input into the -10°C environment.

[0024] (Calculation of the time required for the hardness to exceed A0 + 20 at -10°C (crystallization time)) Subsequently, determine the time required for the hardness to exceed A0 + 20. Specifically, put the sample into a -10°C low-temperature constant temperature bath and perform a hardness measurement using a Type A durometer in the low-temperature constant temperature bath at regular intervals. The sample is preferably put into the -10°C low-temperature constant temperature bath within 1 hour and more preferably within 30 minutes after the end of the above 1-hour standing time. Here, let the Type A durometer hardness X minutes after input be A X and find the time required for A X to exceed A0 + 20. The time required for A X to exceed A0 + 20 is defined as the crystallization time. Note that the hardness measurement using the durometer is preferably performed three times with the measurement location shifted, and the average value of the instantaneous values is recorded. Here, the instantaneous value refers to the hardness value at the moment when the needle of the durometer is pressed against the sample.

[0025] The crystallization time can be adjusted by controlling the manufacturing conditions of the chip, the types and amounts of ingredients during the production of the chloroprene-based polymer latex, particularly the types and compounding amounts of the monomers used in the polymerization, the polymerization conditions, and the thermal history throughout the entire process, and finally controlling the degree of branching of the polymer in the obtained chip. According to the prior art, it was difficult to achieve both the properties such as blocking property, brushability, and coloring that deteriorate as the thermal history increases and the degree of branching of the polymer increases, and the properties such as layer separation resistance that improve as the degree of branching of the polymer increases, and obtain a chip excellent in all these properties. However, according to the present invention, by appropriately controlling the heat storage property and the crystallization time, a chip excellent in blocking resistance and soluble in an organic solvent in a short time can be obtained, and an adhesive composition excellent in brushability, layer separation resistance, and free of coloring can be obtained.

[0026] <Shape> The chip according to an embodiment of the present invention is preferably in a scale shape. The chip according to an embodiment of the present invention preferably has a thickness of 10 mm or less, more preferably 7 mm or less. The thickness is, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 mm, and may be within the range between any two of the exemplified values. The chip according to an embodiment of the present invention preferably has a major axis of 50 mm or less, more preferably 45 mm or less. The major axis is, for example, 10, 15, 20, 25, 30, 35, 40, 45, 50 mm, and may be within the range between any two of the exemplified values. The chip according to an embodiment of the present invention preferably has a minor axis of 22 mm or less, more preferably 20 mm or less. The minor axis is, for example, 10, 12, 14, 16, 18, 20, 22 mm, and may be within the range between any two of the exemplified values. Also, the minor axis can be the maximum length in the direction perpendicular to the major axis. By having the above shape, it is easy to obtain a chip having the above heat storage property. The shape of the chip can be adjusted by appropriately controlling the chip manufacturing conditions, particularly the die shape during chip forming, the number and rotation speed of cutting blades, the discharge speed, the die head temperature, the ratio of the discharge speed to the cutting blade rotation speed, and the like.

[0027] <Height of the liquid level inside the glass tube during stirring of the toluene solution (brushability)> For the chip according to one embodiment of the present invention, the chip is dissolved in toluene to form a toluene solution of 10% by mass of chloroprene-based polymer rubber. The toluene solution of 10% by mass of the chloroprene-based polymer rubber adjusted to 20°C is immersed in the toluene solution of 10% by mass of the chloroprene-based polymer rubber adjusted to 20°C to a depth of 30 mm with a glass tube having an inner diameter of 6 mm and an outer diameter of 8 mm. When the glass tube is rotated at 2000 rpm for 30 seconds, Let the lowest liquid level height outside the glass tube be the lowest liquid level height H0 outside the glass tube, When the highest liquid level height inside the glass tube is the highest liquid level height H1 inside the glass tube, Preferably, the difference between the lowest liquid level height H0 outside the glass tube and the highest liquid level height H1 inside the glass tube is 10 mm or less. As shown in FIG. 1, when the glass tube immersed in the toluene solution is rotated, the liquid levels inside and around the glass tube rise, and the liquid level outside the glass tube away from the glass tube drops slightly compared to the non-rotating state. In this specification, when the glass tube is rotated at 2000 rpm for 30 seconds, the inside of the glass tube is designated as H1, and the lowest liquid level height outside the glass tube is designated as the lowest liquid level height H0 outside the glass tube. In this specification, the "difference between the lowest liquid level height H0 outside the glass tube and the highest liquid level height H1 inside the glass tube" during the rotation of the glass tube is also referred to as the "height of the liquid level inside the glass tube during stirring of the toluene solution". The height of the liquid level inside the glass tube during stirring of the toluene solution is specifically, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 mm, and may also be within the range between any two of the numerical values exemplified here. The height of the liquid level inside the glass tube during stirring of the toluene solution can be specifically evaluated by the method described in the examples. The liquid level height in the glass tube during the stirring of the toluene solution is considered to be related to the structure of the chloroprene-based polymer contained in the chip, specifically, the amount of the linear polymer and the amount of the branched polymer. It is considered that when the degree of branching of the polymer decreases, the liquid level height in the glass tube during the stirring of the toluene solution decreases. The liquid level height in the glass tube during the stirring of the toluene solution can be adjusted by adjusting the manufacturing conditions of the chip, particularly the polymerization temperature and the degree of polymerization, or by appropriately controlling the heat history of the chloroprene-based polymer in the chloroprene-based polymer latex manufacturing process and the chip manufacturing process, as well as the heat storage property of the chip. As an example, when the polymerization temperature and the degree of polymerization are decreased, the degree of branching of the polymer decreases, and the liquid level height in the glass tube during the stirring of the toluene solution tends to decrease. The phenomenon of the liquid level of the toluene solution rising is due to the Weissenberg effect. The higher the liquid level height in the glass tube during the stirring of the toluene solution, the worse the brush coating property becomes. The deterioration of the brush coating property means that the viscosity of the adhesive is high and it becomes wavy during coating and cannot be coated with a uniform thickness. By making the liquid level height in the glass tube during the stirring of the toluene solution equal to or less than the above numerical value, the brush coating property becomes even better.

[0028] <Yellowness> For the chip according to an embodiment of the present invention, the absorbance at a wavelength of 440 nm of a toluene solution obtained by dissolving the chip in toluene and containing 5% by mass of the chloroprene-based polymer rubber is preferably 0.30 or less. Specifically, the absorbance is, for example, 0.01, 0.03, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, and it may be within the range between any two of the numerical values exemplified here. Specifically, the above absorbance can be evaluated by the method described in the examples. The above absorbance is considered to be related to the amount of conjugated double bonds in the chloroprene-based polymer rubber, and can be adjusted by appropriately controlling the manufacturing conditions of the chip, particularly the heat history of the chloroprene-based polymer in the chloroprene-based polymer latex manufacturing process and the chip manufacturing process, as well as the heat storage property of the chip.

[0029] <Solubility in organic solvents> When 100 g of the chip according to an embodiment of the present invention is dissolved in 400 g of an organic solvent containing cyclohexane and ethyl acetate at a mass ratio of 1:1 at 23°C, the time until the chip is dissolved in the organic solvent is preferably 300 minutes or less. Specifically, the dissolution time is, for example, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300 minutes, and may be within the range between any two of the values exemplified herein. Specifically, the above dissolution time can be evaluated by the method described in the examples. The above dissolution time can be adjusted by highly controlling the manufacturing conditions of the chip, particularly the types and amounts of the ingredients during the production of the chloroprene-based polymer latex, and the molding conditions of the chip, and controlling the components, specific surface area, shape, etc. of the chip. Since the chip according to an embodiment of the present invention has excellent solubility in an organic solvent, an adhesive composition or the like can be produced in a short time, and productivity can be improved.

[0030] <Total content of alkaline earth metals, magnesium, aluminum, and zinc> In the chip according to an embodiment of the present invention, the total content of alkaline earth metals, magnesium, aluminum, and zinc is preferably 1 to 5000 mg / kg. Specifically, the total content of alkaline earth metals, magnesium, aluminum, and zinc is, for example, 1, 10, 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000 mg / kg, and may be within the range between any two of the values exemplified herein. The contents of alkaline earth metals, magnesium, aluminum, and zinc can be measured, for example, by high-frequency inductively coupled plasma optical emission spectrometry (ICP-OES). Specifically, first, the chip is cut into pieces of 5 mm square or less with scissors. Weigh 0.5 g of the cut sample, add 8 mL of nitric acid, and decompose and solubilize it using a microwave decomposition device. After cooling the obtained decomposition solution, it is made up to 25 mL and can be measured with a high-frequency inductively coupled plasma optical emission spectrometer. The contents of alkaline earth metals, magnesium, aluminum, and zinc can be adjusted by controlling the chip manufacturing conditions, particularly the type and amount of the coagulant during the coagulation of the chloroprene-based polymer rubber.

[0031] The above-mentioned chip can be suitably used for an adhesive composition. Since the above-mentioned chip is excellent in blocking resistance, it is difficult to adhere to each other and has good handleability during the production of the adhesive composition. In addition, it dissolves in an organic solvent in a short time, and an adhesive composition can be obtained in a short time. Furthermore, the obtained adhesive composition is excellent in brushability and layer separation resistance and has little coloring.

[0032] 3. Method for producing a chip containing chloroprene-based polymer rubber The method for producing a chip containing chloroprene-based polymer rubber according to the present invention is not particularly limited. The production method according to one embodiment of the present invention is A separation step of separating chloroprene-based polymer rubber from a chloroprene-based polymer latex by adding a coagulant to the chloroprene-based polymer latex containing chloroprene-based polymer rubber to obtain a composition containing chloroprene-based polymer rubber, A molding step of molding a composition containing chloroprene-based polymer rubber with an extruder to obtain a chip containing chloroprene-based polymer rubber can be provided. In addition, the production method according to one embodiment of the present invention may further include, before the above separation step, An emulsion polymerization step of emulsion polymerizing a monomer containing chloroprene monomer to obtain a chloroprene-based polymer latex containing chloroprene-based polymer rubber can be provided.

[0033] 3.1 Emulsion polymerization process In the emulsion polymerization process according to one embodiment of the present invention, chloroprene monomer, or 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, and a polymerization terminator is added when the target polymerization rate is reached to obtain a chloroprene-based polymer latex. Further, unreacted monomers can be removed from the chloroprene-based polymer latex thus obtained by a steam flash method, a concentration method, or the like.

[0034] <Emulsifier · Dispersant> The emulsifier is not particularly limited, and known anionic, nonionic, and cationic emulsifiers used in the polymerization of chloroprene-based polymers can be used. Examples of the anionic emulsifier include carboxylic acid type, sulfonic acid type, sulfate ester type, etc. For example, higher fatty acid salts, alkenyl succinates, alkali metal salts of rosin acid, alkyl sulfonates having 8 to 20 carbon atoms, alkyl aryl sulfates, condensates of sodium naphthalene sulfonate and formaldehyde, etc. can be mentioned. Examples of the nonionic emulsifier include polyvinyl alcohol or its copolymer (for example, copolymer with acrylamide), polyvinyl ether or its copolymer (for example, copolymer with maleic acid), polyvinyl pyrrolidone or its copolymer (for example, copolymer with vinyl acetate), or those obtained by chemically modifying these (co)polymers, or cellulose derivatives (hydroxyethyl cellulose), etc. Examples of the cationic emulsifier include aliphatic amine salts, aliphatic quaternary ammonium salts, etc. For example, octadecyl trimethyl ammonium chloride, dodecyl trimethyl ammonium chloride, dilauryl dimethyl ammonium chloride, etc. can be mentioned. Among these, 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 the emulsifier can be 2.0 to 7.5 parts by mass with respect to 100 parts by mass of the monomer.

[0035] <pH adjuster> The raw materials added to the polymerization system at the start of polymerization can include a pH adjuster. Examples of the pH adjuster include potassium pyrosulfite, potassium sulfite, potassium bisulfite, potassium phosphate, dipotassium hydrogen phosphate, sodium pyrosulfite, sodium sulfite, sodium bisulfite, sodium phosphate, disodium hydrogen phosphate, potassium hydroxide, sodium hydroxide, and the like. The pH adjuster may be used alone or in combination of two or more thereof. Among these pH adjusters, it is preferable to use potassium hydroxide or sodium hydroxide because they have a high effect of increasing the pH value. The addition amount of the pH adjuster can be 0.01 to 2.0 parts by mass with respect to 100 parts by mass of the monomer.

[0036] <Polymerization initiator> The raw materials added to the polymerization system at the start of polymerization can include a polymerization initiator. As the polymerization initiator, potassium persulfate, benzoyl peroxide, ammonium persulfate, hydrogen peroxide, etc. that are usually used in radical polymerization can be used. The addition amount of the polymerization initiator can be 0.001 to 1 part by mass with respect to 100 parts by mass of the monomer.

[0037] <Chain transfer agent> There is no particular limitation on the chain transfer agent as long as it is generally used in the production of chloroprene polymers. For example, 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 known chain transfer agents such as iodoform can be used. The addition amount of the chain transfer agent can be 0.001 to 10 parts by mass with respect to 100 parts by mass of the total monomers.

[0038] <Coincidence temperature> The coincidence temperature is desirably in the range of 0 to 55 °C from the viewpoint of easy reaction control. From the viewpoint of performing the polymerization reaction more smoothly and safely, it is desirable that the lower limit value of the polymerization temperature is 5 °C or higher and the upper limit value is 45 °C or lower, more preferably less than 40 °C, and even more preferably 35 °C or lower. By adjusting the polymerization temperature, the degree of branching of the obtained chloroprene-based polymer rubber can be adjusted, and the crystallization time of the obtained chips can be controlled.

[0039] <Polymerization rate> In the emulsion polymerization step, when the monomer reaches the desired polymerization rate, the polymerization is stopped by adding a polymerization terminator, and a polymerized liquid in which the reaction has ended can be obtained. The polymerization rate at the end of the polymerization can be less than 100%, and can be in the range of 60 to 95%.

[0040] <Polymerization terminator> As the polymerization terminator, for example, thiophenylamine, 4-tert-butylcatechol, 2,2'-methylenebis-4-methyl-6-tert-butylphenol, etc. can be used.

[0041] <Removal of unreacted monomer> From the polymerized liquid after the polymerization is completed, the unreacted monomer after the emulsion polymerization is completed can be removed by a method such as a conventional steam stripping method or a vacuum heating evaporation method to obtain a chloroprene-based polymer latex.

[0042] 3.2 Separation step The production method according to an embodiment of the present invention can include a separation step of separating the chloroprene-based polymer rubber from the chloroprene-based polymer latex by adding a coagulant to the chloroprene-based polymer latex containing the chloroprene-based polymer rubber obtained in the emulsion polymerization step to obtain a composition containing the chloroprene-based polymer rubber.

[0043] In the separation step, it is preferable to separate the chloroprene-based polymer rubber by adding a coagulant to the chloroprene-based polymer latex obtained in the emulsion polymerization step. Generally, as a method for separating the chloroprene-based polymer rubber from the chloroprene-based polymer latex, a method of emulsion breaking using a freezing roll is used. However, the method using a freezing roll has a problem of poor energy efficiency. Further, the method using a freezing roll is often carried out in an open system, and there is a problem of a poor working environment. In the production method according to an embodiment of the present invention, the energy efficiency of the process can be improved by separating the chloroprene-based polymer rubber using a coagulant without using a freezing roll. Further, in the production method according to an embodiment of the present invention, the separation step can be carried out in an extruder, more preferably, the separation step and the drying step can be carried out in an extruder, and even more preferably, the separation step, the drying step, and the molding step can be carried out in an extruder, and the working environment can be improved. Note that carrying out the molding step in an extruder includes a case where a part of the molding step is carried out in an extruder.

[0044] The coagulant is preferably an aqueous solution containing at least one selected from the group consisting of alkaline earth metal salts, magnesium salts, aluminum salts, and zinc salts, and more preferably an aqueous solution containing at least one of chlorides, sulfates, nitrates, and phosphates of calcium, magnesium, aluminum, and zinc. Among these, the coagulant is more preferably an aqueous solution containing at least one selected from the group consisting of calcium chloride, magnesium chloride, magnesium sulfate, aluminum chloride, and aluminum sulfate. The coagulant is preferably added in such an amount that the total of the alkaline earth metal salt, magnesium salt, aluminum salt, and zinc salt is 0.05 to 10 parts by mass with respect to 100 parts by mass of the chloroprene-based polymer latex. By setting the total of the alkaline earth metal salt, magnesium salt, aluminum salt, and zinc salt to be equal to or higher than the above lower limit, sufficient coagulation can be achieved and a sufficient recovery rate can be obtained. Further, by setting the total of the alkaline earth metal salt, magnesium salt, aluminum salt, and zinc salt to be equal to or lower than the above lower limit, the production cost can be suppressed.

[0045] The chloroprene polymer latex and the coagulant can be mixed by a screw in an extruder. The mixing conditions are preferably adjusted as appropriate so that the chloroprene polymer latex and the coagulant are sufficiently mixed. As an example, the outer diameter of the screw can be 20 to 120 mm, specifically, for example, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120 mm, and it may also be within the range between any two of the values exemplified herein. The ratio L / D of the length (L) to the diameter (D) of the screw can be 40 to 80, specifically, for example, 40, 45, 50, 55, 60, 65, 70, 75, 80, and it may also be within the range between any two of the values exemplified herein. The screw rotation speed can be 30 to 160 rpm, specifically, for example, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160 rpm, and it may also be within the range between any two of the values exemplified herein. When the supply amount of the chloroprene polymer latex is 100 parts by mass / hour, the supply amount of the coagulant can be 10 to 200 parts by mass / hour, specifically, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200 parts by mass / hour, and it may also be within the range between any two of the values exemplified herein. By setting the above conditions within the above numerical ranges respectively, the shear heat generation by the screw can be suppressed, the deterioration of the chloroprene polymer rubber can be suppressed, it is easier to obtain a chip that is more excellent in blocking resistance, brushability, and layer separation resistance, and has an adhesive composition without coloring. Furthermore, by setting the above conditions within the above numerical ranges respectively, the chloroprene polymer latex and the coagulant are more sufficiently mixed, and the chloroprene polymer rubber can be separated more efficiently.

[0046] The solidified chloroprene-based polymer rubber is separated from the suspension containing the solid, and then preferably dehydrated with a dehydrating device to obtain a composition containing the chloroprene-based polymer rubber. Examples of the dehydrating device include known dehydrating devices such as a slit, a strainer, or a dehydrating roll.

[0047] The production method according to an embodiment of the present invention may further include a drying step of removing water from the composition containing the chloroprene-based polymer rubber separated in the separation step. In the drying step, it is preferable that the ambient temperature is 130°C or lower. Specifically, the temperature in the drying step is, for example, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130°C, and it may be within the range between any two of the values exemplified herein. The drying step is preferably within 10 minutes. The drying step preferably includes a high-temperature drying step of heating at 100°C or higher and a low-temperature drying step of heating at less than 100°C. In the high-temperature drying step, the ambient temperature can be, for example, 100, 110, 120, 130°C, and it may be within the range between any two of 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, 100°C, and it may be within the range between any two of the values exemplified herein. The low-temperature drying step is preferably within 7 minutes. In one embodiment of the present invention, the drying step preferably includes a low-temperature drying step after the high-temperature drying step. By including the low-temperature drying step after the high-temperature drying step, the first half with a large amount of remaining water and affected by the cooling effect of latent heat can be dried at a high temperature, and the second half with less water and less affected by the cooling effect of latent heat can be dried at a low temperature, thereby suppressing changes due to the heat of the chips.

[0048] 3.3 Molding step The manufacturing method according to an embodiment of the present invention can include a molding step of molding a composition containing a chloroprene-based polymer rubber with an extruder to obtain chips containing the chloroprene-based polymer rubber. For the molding step, for example, the side hot cut method, the center hot cut method, etc. can be used.

[0049] In the molding step, it is preferable that the temperature of the chips containing the chloroprene-based polymer rubber immediately after discharge is less than 150°C. The temperature immediately after discharge is, for example, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150°C, and it may be within the range between any two of the numerical values exemplified herein. It is preferable that the temperature of the chips containing the chloroprene-based polymer rubber 60 seconds after discharge is 130°C or lower. The temperature 60 seconds after discharge is, for example, 50, 60, 70, 80, 90, 100, 110, 120, 130°C, and it may be within the range between any two of the numerical values exemplified herein. Here, the temperature immediately after discharge and the temperature 60 seconds after discharge of the chips containing the chloroprene-based polymer rubber can be determined with a contact thermometer. By setting the temperature immediately after discharge and the temperature 60 seconds after discharge below the above upper limits, it is possible to suppress changes in the properties of the chloroprene-based polymer rubber due to heat, and further, it is possible to obtain chips that are excellent in brushability and layer separation resistance and are likely to become an adhesive composition without coloring. The temperature immediately after discharge and the temperature 60 seconds after discharge can be controlled by adjusting conditions such as the die head temperature, discharge amount, number and rotation speed of cutting blades, die shape, etc. in the molding step.

[0050] In the molding step according to an embodiment of the present invention, it is preferable that the temperature of the die head is 120°C or lower. The temperature of the die head is, for example, 100, 105, 110, 115, 120°C, and it may be within the range between any two of the numerical values exemplified herein. As an example, in the molding process according to an embodiment of the present invention, the discharge rate of the composition containing chloroprene-based polymer rubber can be set to 15 to 35 kg / h. Specifically, for example, it can be 15, 20, 25, 30, or 35 kg / h, and it may also be within the range between any two of the numerical values exemplified herein. As an example, in the molding process according to an embodiment of the present invention, the discharge rate of the composition containing chloroprene-based polymer rubber can be set to 1200 to 2800 mm / min. Specifically, for example, it can be 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, or 2800 mm / min, and it may also be within the range between any two of the numerical values exemplified herein. Also, as an example, in the molding process according to an embodiment of the present invention, the shape of the die can be set to a diameter of 5 to 25 mm. Specifically, for example, it can be 5, 10, 15, 20, or 25 mm, and it may also be within the range between any two of the numerical values exemplified herein. The die can have 1 to 5 holes. The die can have, for example, 1, 2, 3, 4, or 5 holes, and it may also be within the range between any two of the numerical values exemplified herein. Furthermore, as an example, in the molding process according to an embodiment of the present invention, the number of cutting blades can be set to 1. The rotational speed of the cutting blade can be set to 200 to 1000 rpm. Specifically, for example, it can be 200, 300, 400, 500, 600, 700, 800, 900, or 1000 rpm, and it may also be within the range between any two of the numerical values exemplified herein. The ratio (Y / Z) of the discharge rate Y (mm / min) of the chloroprene-based polymer rubber in the die head to the rotational speed Z (rpm) of the cutting blade for cutting the discharged chloroprene-based polymer rubber is preferably 1 to 10. Y / Z can be, specifically, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, and it may also be within the range between any two of the numerical values exemplified herein. As an example, by setting the above conditions within the above numerical ranges respectively, the chips are likely to have a desired thickness, and it is easy to suppress heat generation due to pressure loss in the die part. By setting the above conditions within the above numerical ranges respectively, the temperature and heat storage property of the chip after ejection can be more appropriately controlled, making it easier to obtain a chip that is more excellent in blocking resistance, brush coating property, layer separation resistance, and can provide an adhesive composition without coloring.

[0051] The manufacturing method according to an embodiment of the present invention preferably does not have a step of water-cooling the chip after the molding step. By having a step of water-cooling the chip, it is possible to rapidly cool the chip. However, in that case, it is necessary to provide a further step of removing water, and the chip may be subjected to a longer heat history, which is also not preferable from the perspective of energy efficiency. Since the chip according to an embodiment of the present invention has a sufficiently small heat storage property, even without having a step of water-cooling the chip after the molding step, it is possible to sufficiently suppress the alteration of the chloroprene-based polymer rubber.

[0052] 4. Adhesive Composition The adhesive composition according to an embodiment of the present invention includes a solution in which the above chip is dissolved in an organic solvent. Since the above chip contains a chloroprene-based polymer rubber whose alteration by heat is suppressed, the resulting adhesive composition is excellent in brush coating property and layer separation resistance and has little coloring.

[0053] The type of the above organic solvent is not limited. For example, organic solvents such as toluene, xylene, acetone, methyl ethyl ketone, n-hexane, cyclohexane, methylcyclohexane, cyclopentane, isopropyl acetate, and ethyl acetate can be used. The organic solvent is not an aromatic solvent such as toluene, xylene, or ethylbenzene that causes sick building syndrome, but can be a non-aromatic solvent such as n-hexane, cyclohexane, methylcyclohexane, acetone, methyl ethyl ketone, ethyl acetate, or butyl acetate. It is more preferable to dissolve the above-mentioned chloroprene-based polymer rubber only in a mixture of poor solvents that are individually poor in solubility for the chloroprene-based polymer rubber. As an example, an organic solvent with a cyclohexane:ethyl acetate = 1:1 (mass ratio) can be mentioned.

[0054] The amount of the organic solvent used may be appropriately adjusted according to the use and type of the adhesive, and is not particularly limited. However, if the viscosity of the adhesive composition is adjusted to be 3500 to 4500 mPa·S, it is preferable because the balance between the heat-resistant adhesive strength and the initial adhesive strength as an adhesive becomes good.

[0055] In addition to the solvent, the adhesive composition may contain a metal oxide, a tackifying resin, and an antioxidant. By adding these additives to the adhesive composition, the initial adhesive strength, the normal-state adhesive strength, the spray coating property, etc. of the obtained adhesive composition can be improved.

[0056] As the metal oxide, for example, zinc oxide (zinc white), aluminum oxide, titanium oxide, magnesium oxide, etc. can be used. As the tackifying resin, for example, a phenolic resin, a rosin resin, a coumarone resin, a petroleum resin, etc. can be used. As the anti-aging agent, for example, 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], thiodiethylene bis[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-hydroxyphenylpropionamide), 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], tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetramethylthiuram monosulfide, dibutylhydroxytoluene, etc. can be used.

[0057] The adhesive composition may further contain a formaldehyde scavenger, a filler, etc. according to the desired physical properties.

[0058] As the formaldehyde scavenger, for example, pyrrolidine, piperidine, piperazine, morpholine, melamine, dicyandiamide, urea, ethylene urea, 4,5-dimethoxyethylene urea, propylene urea, 5-methylpropylene urea, 5-hydroxypropylene urea, 5-methoxypropylene urea, oxalyl urea (parabanic acid), hydrazobenzothiazole, semicarbazide, thiosemicarbazide can be used. The formaldehyde scavenger can capture formaldehyde, which is a harmful volatile substance. As the filler, talc, calcium carbonate, clay, smectite, silica, hydrotalcite, mica, etc. can be used.

[0059] Also, 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.

[0060] The adhesive composition according to an embodiment of the present invention may further contain at least one raw rubber (unvulcanized or uncrosslinked 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.

[0061] The method for producing the adhesive composition is not particularly limited, and known machines and apparatuses may be used. As a method for producing the adhesive composition, generally, an alkylphenol resin or magnesium oxide is dissolved in an organic solvent, and after standing at room temperature for 10 to 20 hours, for example, a method of dissolving a chip containing a chloroprene-based polymer rubber, a metal oxide, an antioxidant, etc. can be adopted.

[0062] The adhesive composition according to an embodiment of the present invention is used as an adhesive or a raw material for an adhesive. For example, an adhesive can be obtained by adding other additives to the above adhesive composition or mixing the above adhesive composition with other adhesive compositions. The adhesive can be suitably used for joining and adhering the same or different kinds of materials such as paper, wood, cloth, leather, jersey, leather, rubber, plastic, foam, pottery, glass, mortar, cement-based materials, ceramics, and metal.

[0063] The adhesive composition according to an embodiment of the present invention is preferably such that no layer separation is observed even after more than 6 weeks when it is put into a glass container after preparation and stored in a constant temperature bath at 60 °C under light shielding, and more preferably such that no layer separation is observed even after more than 7 weeks.

Examples

[0064] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not construed as being limited thereto.

[0065] (Example 1) (Production of chloroprene-based polymer latex) Using a reactor with an internal volume of 5 liters, under a nitrogen atmosphere, 3.3 parts by mass of disproportionated gum rosin sodium salt 3R-70N (manufactured by Arakawa Chemical Industries), 0.5 parts by mass of disproportionated tall rosin sodium salt 6R-70N (manufactured by Harima Kasei Co., Ltd.), 0.4 parts by mass of sodium salt of condensate of naphthalenesulfonic acid and formaldehyde (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, and then potassium persulfate was added as a polymerization initiator, and polymerization was carried out under a nitrogen stream at a polymerization temperature of 10°C. When the polymerization conversion rate reached 72% or more, a phenothiazine emulsion was added as a polymerization terminator to stop the reaction. Unreacted monomers were removed under reduced pressure to obtain chloroprene-based polymer latex 1 with a solid content of 40%.

[0066] (Production of chips containing chloroprene-based polymer rubber) Chips containing chloroprene-based polymer rubber were produced from the chloroprene-based polymer latex. The obtained chloroprene-based polymer latex 1 and a coagulant (1% calcium chloride, 0.6% acetic acid aqueous solution) were supplied to a twin-screw extruder and mixed with a screw to coagulate the chloroprene-based polymer latex. Then, the obtained coagulum was dehydrated, washed, and dried to obtain chloroprene-based polymer rubber, and then the obtained chloroprene-based polymer rubber was chipped by a molding process using side hot cut. The above coagulation, dehydration, washing, drying, and molding processes (the process of extruding into a rod shape) were carried out in a twin-screw extruder.

[0067] The manufacturing conditions of the above process are shown below. Apparatus: Twin-screw extruder (screw outer diameter: φ47 mm, L / D: 59.5) Die shape (Φ15mm × 1 hole) Number of cutting blades: 1 Condition: Screw rotation speed: 85 rpm Latex supply rate: 75 kg / h Coagulant supply rate: 50 kg / h Drying process temperature: First half: 120°C × 2 minutes, Second half: 60°C × 3 minutes Die head temperature: 110°C Rubber discharge rate: 26 kg / h Discharge speed: 2130 mm / min Cutting blade rotation speed: 600 rpm

[0068] (Example 2) In the method for manufacturing the chip, the chip was manufactured in the same manner as in Example 1 except that the cutting blade rotation speed was 360 rpm.

[0069] (Example 3) In the method for manufacturing the chip, the chip was manufactured in the same manner as in Example 1 except that the cutting blade rotation speed was 900 rpm.

[0070] (Example 4) (Manufacture of chloroprene-based polymer latex) Polymerization was carried out under the same conditions as in Example 1 except that the polymerization temperature was 35°C, and unreacted monomers were removed under reduced pressure to obtain chloroprene-based polymer latex 4 with a solid content of 40%.

[0071] (Manufacture of chips containing chloroprene-based polymer rubber) The chip was manufactured in the same manner as in Example 1 except that chloroprene-based polymer latex 4 was used.

[0072] (Comparative Example 1) (Manufacture of chips containing chloroprene-based polymer rubber) In the method for manufacturing the chip, the chip was manufactured in the same manner as in Example 1 except that the cutting blade rotation speed was 150 rpm.

[0073] (Comparative Example 2) <Production of chloroprene-based polymer latex> Polymerization was carried out under the same conditions as in Example 1 except that the chloroprene monomer was 97.5 parts by mass, 2,3-dichloro-1,3-butadiene was 2.5 parts by mass, and the polymerization temperature was 40°C. Unreacted monomers were removed under reduced pressure to obtain a chloroprene-based polymer latex 6 with a solid content of 40%.

[0074] <Production of chips containing chloroprene-based polymer rubber> Chips were produced in the same manner as in Example 1 except that the chloroprene-based polymer latex 6 was used.

[0075] <Evaluation of chips> The obtained chips were evaluated as follows.

[0076] <Heat storage property> The heat storage property of the chips was evaluated by the following procedure. First, a K-type thermocouple was inserted into the chip so that the tip was near the center of the chip. In this state, the chip was placed in an oven set at 150°C and heated until the temperature near the center reached 140°C. After the temperature near the center of the chip reached 140°C, the chip was taken out into an environment of 23°C, and the temperature near the center of the chip was measured over time. During this period, the chip was held in the air so that its surface did not come into contact with other objects. The temperatures immediately after taking out the chip into the 23°C environment, 10 seconds later, 30 seconds later, and 60 seconds later are shown in Table 1.

[0077] <Chip shape> The thickness, major axis, and minor axis of the chips were measured with calipers. The chips were in a scale shape, and the direction perpendicular to the substantially parallel planes was defined as the thickness direction. The maximum length of the plane perpendicular to the thickness direction was defined as the major axis, and the length perpendicular to the major axis was defined as the minor axis. The measurement results are shown in Table 1.

[0078] <Crystallization time> The obtained chip was processed into a sheet shape with a thickness of 3 mm using an 8-inch diameter roll (surface temperature 30°C). This sheet was placed in a mold with a depth of 6 mm × length of 130 mm × width of 25 mm, with three sheets stacked in such a way that the longitudinal direction was the column direction of the roll (the direction along the roll circumference when processed into a sheet shape by the roll), and pressed at 70°C for 20 minutes. During pressing, in order to remove air, bumping was performed 5 times. The sample taken out from the mold was left standing in a 23°C environment for 1 hour, and immediately after standing for 1 hour, hardness measurement was performed using a Type A durometer based on JIS K 6253-3. The Type A durometer hardness at this time was designated as A0. Here, A0 indicates the hardness before being put into a -10°C environment. Subsequent to the Type A durometer hardness measurement, the sample was put into a -10°C low-temperature constant temperature bath. The sample was subjected to hardness measurement using a Type A durometer in the low-temperature constant temperature bath at regular intervals. The Type A durometer hardness X minutes after being put in was designated as A X and the time required for A X to exceed A0 + 20 was defined as the crystallization time. The measurement results are shown in Table 1. Note that the hardness measurement using the durometer was performed 3 times with the measurement positions shifted, and the average value of the instantaneous values was recorded. Here, the instantaneous value refers to the hardness value at the moment when the needle of the durometer was pressed against the sample.

[0079] <Height of the liquid level inside the glass tube during stirring of the toluene solution> 17 g of the chip was added to 153 g of toluene and stirred until completely dissolved to obtain a 10% toluene solution of chloroprene-based polymer rubber. The 10% toluene solution of chloroprene-based polymer rubber adjusted to 20°C was put into a beaker, and a transparent glass tube with an inner diameter of 6 mm and an outer diameter of 8 mm was immersed 30 mm, and rotated at 2000 rpm for 30 seconds. When the lowest liquid level height outside the glass tube was designated as the lowest liquid level height H0 outside the glass tube and the highest liquid level height inside the glass tube was designated as the highest liquid level height H1 inside the glass tube, the difference between the lowest liquid level height H0 outside the glass tube and the highest liquid level height H1 inside the glass tube was measured with a caliper. The results are shown in Table 1.

[0080] <Layer separation resistance of the adhesive> 50 parts by mass of an alkylphenol resin (Tamanol 526: manufactured by Arakawa Chemical Industries, Ltd.) and 3 parts by mass of magnesium oxide (Kyowa Mag #150: manufactured by Kyowa Chemical Industry Co., Ltd.) were dissolved in 100 parts by mass of cyclohexane, and a chelation reaction was carried out at room temperature for 16 hours. Next, to the cyclohexane solution, 100 parts by mass of chips, 1 part by mass of 2,6-di-t-butyl-4-methylphenol (No Crack 200: manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.), 3 parts by mass of magnesium oxide, 1 part by mass of zinc oxide, 180 parts by mass of cyclohexane, 75 parts by mass of n-hexane, 120 parts by mass of acetone, and 55 parts by mass of isopropyl acetate were added, and the mixture was stirred until the chips containing the chloroprene-based polymer rubber were completely dissolved to obtain an adhesive composition.

[0081] The obtained adhesive composition was placed in a glass container and stored in a constant temperature bath at 60 °C under light shielding. The appearance of the adhesive composition was observed over 8 weeks, and the week in which component separation was observed was recorded. The results are shown in Table 1.

[0082] <Yellowness> The chips were dissolved in toluene to a concentration of 5% by mass, and the absorbance at a wavelength of 440 nm was measured using a "Spectrophotometer UV-2600" manufactured by Shimadzu Corporation to evaluate the hue (yellowness). The results are shown in Table 1.

[0083] <Solubility in organic solvents> 100 g of chips were mixed with 400 g of an organic solvent (cyclohexane / ethyl acetate = 1 / 1 (mass ratio)), and the mixture was stirred with a stirrer at 23 °C, and the time until the polymer was completely dissolved was measured. The completion of dissolution was judged visually. The results are shown in Table 1.

[0084] <Blocking resistance> The chip was processed into a sheet with a diameter of 8 inches (surface temperature 30 °C) and a thickness of 3 mm. This sheet was placed in a mold with a depth of 2 mm × length of 150 mm × width of 100 mm such that the longitudinal direction was the column arrangement direction of the samples, and pressed at 70 °C for 20 minutes to produce a sheet. Two test pieces of 60 mm × 60 mm were taken from the produced sheet. The two stacked test pieces were sandwiched between glass plates with a thickness of 2 mm × width of 100 mm × length of 100 mm and held in a constant temperature bath at 40 °C for 1 hour. After taking it out and leaving it to stand in the standard state (23 °C) for 30 minutes, the two test pieces were peeled off from each other, and the presence or absence of blocking (adhesion) between the test pieces when peeling was examined and evaluated according to the following evaluation criteria.

[0085] (Blocking of test pieces) ◎ There was no blocking between the test pieces. ○ The test pieces were slightly blocked. × The test pieces were significantly blocked.

[0086] (Total content ratio of alkaline earth metals, aluminum, and zinc) Regarding the chip of Example 1, the content ratios of alkaline earth metals, magnesium, aluminum, and zinc were measured by high-frequency inductively coupled plasma optical emission spectrometry (ICP-OES). Specifically, first, the chip was cut into pieces with a size of 5 mm square or less with scissors. 0.5 g of the cut sample was weighed, 8 mL of nitric acid was added, and it was decomposed and solubilized using a microwave decomposition device. After cooling the obtained decomposition solution, it was made up to 25 mL and measured with a high-frequency inductively coupled plasma optical emission spectrometer. It was confirmed that the chip of Example 1 contained 790 mg / kg of calcium.

[0087] [Table 1] [Description of symbols]

[0088] 1 Glass rod 2 Maximum liquid level height H1 inside the glass tube 3 Minimum liquid level height H0 outside the glass tube

Claims

1. A chip for an adhesive composition, comprising a chloroprene-based polymer rubber, wherein when the chip heated to 140°C is held in a 23°C room for 60 seconds, the temperature near the center of the chip is 130°C or lower, The chip was press-molded at 70°C into a sheet with a thickness of 6 mm, taken out of the mold, allowed to stand for 1 hour in an environment of 23°C, and then the type A durometer hardness measured based on JIS K 6253-3 was A ０ and The sheet with a thickness of 6 mm is put into a thermostat at -10°C, and the Shore A durometer hardness after X minutes from the input is A Ｘ When it is Ｘ A ０ The time required for it to exceed A + 20 is less than 500 minutes, chip.

2. The chip is dissolved in toluene to obtain a toluene solution containing 10% by mass of the chloroprene-based polymer rubber, a glass tube with an inner diameter of 6 mm and an outer diameter of 8 mm is immersed 30 mm into the toluene solution containing 10% by mass of the chloroprene-based polymer rubber adjusted to 20°C, when the glass tube is rotated at 2000 rpm for 30 seconds, Let the lowest liquid level height outside the glass tube be the glass tube outside lowest liquid level height H ０ and Let the maximum liquid level height in the glass tube be the maximum liquid level height H in the glass tube １ When it is set as such, The minimum liquid level height H outside the glass tube ０ and the maximum liquid level height H inside the glass tube １ The chip according to claim 1, wherein the difference is 10 mm or less.

3. The chip according to claim 1 or 2, wherein the absorbance at a wavelength of 440 nm of the toluene solution containing 5% by mass of the chloroprene-based polymer rubber obtained by dissolving the chip in toluene is 0.30 or lower.

4. The chip according to claim 1 or claim 2, wherein when 100 g of the chip is dissolved in 400 g of an organic solvent having a cyclohexane:ethyl acetate = 1:1 (mass ratio) at 23°C, the time until the chip is dissolved in the organic solvent is 300 minutes or less.

5. The chip according to claim 1 or claim 2, wherein the total content of alkaline earth metals, magnesium, aluminum and zinc in the chip is 1 to 5000 mg / kg.

6. A method for manufacturing the chip according to claim 1, comprising a separation step of separating the chloroprene-based polymer rubber from the chloroprene-based polymer latex containing the chloroprene-based polymer rubber by adding a coagulant to the chloroprene-based polymer latex containing the chloroprene-based polymer rubber to obtain a composition containing the chloroprene-based polymer rubber, a molding step of molding the composition containing the chloroprene-based polymer rubber with an extruder to obtain a chip containing the chloroprene-based polymer rubber, and in the molding step, the temperature of the chip containing the chloroprene-based polymer rubber immediately after discharge is less than 150°C.

7. The manufacturing method according to claim 6, wherein in the molding step, the temperature of the chip containing the chloroprene-based polymer rubber 60 seconds after discharge is 130°C or lower.

8. The manufacturing method according to claim 6 or 7, wherein in the molding step, the temperature of the die head is 120°C or lower. A manufacturing method in which the ratio Y / Z of the discharge rate Y (mm / min) of the chloroprene-based polymer rubber in the die head to the rotational speed Z (rpm) of the cutting blade that cuts the discharged chloroprene-based polymer rubber is 1 to 10.

9. The manufacturing method according to claim 6 or claim 7, A manufacturing method that does not have a step of water-cooling the chip after the molding step.

10. The manufacturing method according to claim 6 or claim 7, further including a drying step of removing water from the composition containing the chloroprene-based polymer rubber separated in the separation step, wherein the ambient temperature in the drying step is 130°C or lower. Manufacturing method.

11. The manufacturing method according to claim 10, wherein the separation step, the drying step, and the molding step are performed in an extruder.

12. An adhesive composition containing a solution in which the chip according to claim 1 or claim 2 is dissolved in an organic solvent.

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