JP5805965B2 - Chloroprene rubber and adhesive using the same - Google Patents

Description

  The present invention relates to a chloroprene rubber and an adhesive using the same.

Chloroprene rubber is used in various applications because of its excellent heat resistance, weather resistance, ozone resistance, chemical resistance, flame retardancy, and the like.
A solvent-type adhesive is one of the representative examples, and is used in various applications because of its wide adaptability to adherend and good balance of adhesive properties. In recent years, the solvent used in solvent-based adhesives is desired to be converted from aromatic solvents such as toluene, xylene, and ethylbenzene, which cause sick house syndrome, to non-aromatic solvents. However, with this conversion, so-called layer separation that separates into a component that dissolves in an organic solvent and an insoluble component tends to occur when the solvent-based adhesive is stored.
Means for improving the layer separation of the solvent-type adhesive include (1) a method in which a chloroprene copolymer is a copolymer of a monomer having a specific structure and chloroprene, and (2) a polymer structure of chloroprene rubber. A method of controlling has been invented.
As an example of (1), an adhesive having excellent layer separation resistance is known by dissolving a copolymer of chloroprene and a specific ethylenically unsaturated sulfonic acid or salt thereof in an organic solvent. (For example, refer to Patent Document 1).
As an example of (2), polychloroprene latex is heat-treated, and in a 1H-NMR spectrum measured in a deuterated chloroform solvent, the peak area appearing at a chemical shift of 4.13 to 4.30 ppm is controlled, thereby improving resistance. An adhesive having excellent layer separation is known (for example, see Patent Document 2).

JP 2004-076015 A JP 2010-275338 A

Although improvement in the layer separation resistance of the adhesive is recognized by these means, the adhesive strength and handling property (brush coating property) of the adhesive may be sacrificed, and further improvement is necessary.
For example, as in Patent Document 1, when a monomer other than chloroprene is copolymerized, the crystallization rate of the polymer is slower than that of the chloroprene homopolymer, so when used as a solvent-based adhesive, The initial adhesive strength may be insufficient.
As in Patent Document 2, in the method of heat-treating polychloroprene latex, the number of hydroxyl groups in the molecular chain of the chloroprene polymer is increased. Therefore, when the main agent, which is an organic solvent solution of polychloroprene rubber, is combined with a curing agent of an isocyanate compound and used as a two-component solvent-based adhesive, it can be used after mixing the main agent and the curing agent. The time (pot life) to reach the viscosity upper limit may be shortened.

  An object of the present invention is to provide a chloroprene rubber capable of improving the layer separation resistance while maintaining the brushing property of the obtained adhesive and the adhesive using the same.

  The present invention is an average branching index gM having a weight average molecular weight of 1,000,000 to 1,500,000 using linear polystyrene as a reference polymer, measured using a gel permeation chromatograph-multi-angle laser light scattering detector (GPC-MALLS). Is a chloroprene rubber having 1.00 to 1.12. The Mooney viscosity of the chloroprene rubber is preferably 55 to 100 ML (1 + 4) 100 ° C. A toluene solution that rises in a glass tube when a transparent glass tube with an inner diameter of 6 mm is submerged 30 mm in a solution prepared by dissolving chloroprene rubber in toluene at a concentration of 10% by mass and adjusted to 20 ° C., and rotated at 2000 rpm for 30 seconds. It is preferable that the maximum height is 10 mm or less. Chloroprene rubber can be used as an adhesive by dissolving in a non-aromatic solvent.

ADVANTAGE OF THE INVENTION According to this invention, the chloroprene rubber which can improve the layer-separation resistance, maintaining the brush coatability of the adhesive obtained, and an adhesive using the same are obtained.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. Note that the present invention is not limited to the embodiments described below.

  Chloroprene rubber is obtained by freeze-coagulating and drying an emulsion (latex) obtained by emulsion polymerization of chloroprene monomer, chloroprene monomer and copolymerizable monomer in the presence of an emulsifying / dispersing agent. It is a synthetic rubber obtained. The chloroprene monomer is 2-chloro-1,3-butadiene. Examples of the monomer copolymerizable with the chloroprene monomer include 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, butadiene, isoprene, styrene, acrylonitrile, acrylic acid or The ester, methacrylic acid or its ester, sulfur, etc. are illustrated. Two or more of these monomers can be used in combination as required. The addition amount of the copolymerizable monomer in the present invention is not particularly limited, but is preferably 30 parts by mass or less with respect to 100 parts by mass of all monomers in order to maintain the properties as a chloroprene rubber.

  The emulsifying / dispersing agent used in the emulsion polymerization is not particularly limited, and various types such as an anionic type, a nonionic type and a cationic type, which are used for usual emulsion polymerization of chloroprene, can be used. Examples of anionic emulsifiers include carboxylic acid type and sulfuric acid ester type, such as rosinate, alkyl sulfonate having 8 to 20 carbon atoms, alkyl aryl sulfate, condensate of sodium naphthalene sulfonate and formaldehyde, alkyl Examples include sodium diphenyl ether disulfonate.

  Among these emulsifying / dispersing agents, rosin acid or its rosin acid is used for the reason that the film-like chloroprene rubber at the time of freeze-coagulation drying after the polymerization can be given appropriate strength to prevent excessive shrinkage and breakage. Most preferably, alkali metal salts are used. Rosin acid is a mixture of resin acid, fatty acid and the like. Resin acids include abietic acid, neoabietic acid, parastrinic acid, pimaric acid, isopimaric acid, dehydroabietic acid, dihydropimaric acid, dihydroisopimaric acid, secodehydroabietic acid, dihydroabietic acid, etc. , Oleic acid, linoleic acid and the like. The composition of these components varies depending on the difference in rosin collection methods classified into gum rosin, wood rosin and tall rosin, pine production area and tree species, distillation purification, and disproportionation (disproportionation) reaction. Not. In view of emulsion stability and ease of handling, use of sodium salt or potassium salt is preferred. The addition amount of the rosinate is not particularly limited, but is preferably 0.5 to 5 parts by mass and more preferably 1 to 4 parts by mass with respect to 100 parts by mass of all monomers. When the amount is less than 0.5 parts by mass, the emulsion stability becomes poor and the polymerization cannot be stably performed. On the other hand, when the amount is more than 5 parts by mass, when the obtained chloroprene rubber is used as a solvent-type adhesive, its water resistance strength and layer separation stability are lowered.

  Although the polymerization temperature at the time of performing emulsion polymerization is not specifically limited, Preferably it is 0-55 degreeC. By setting the polymerization temperature within this range, water in the reaction solution does not coagulate and chloroprene does not volatilize.

  The molecular weight of chloroprene rubber can be adjusted by the amount of chain transfer agent added. That is, when the addition amount of the chain transfer agent is increased, the molecular weight of the chloroprene rubber can be decreased, and when the addition amount is decreased, the molecular weight can be increased. The chain transfer agent to be used is not particularly limited, and a chain transfer agent generally used for polymerization of chloroprene can be used. Examples of the chain transfer agent include long-chain alkyl mercaptans such as n-dodecyl mercaptan and t-dodecyl mercaptan, dialkylxanthogen disulfides such as diisopropylxanthogen disulfide and diethylxanthogen disulfide, and iodoform.

  The amount of chain transfer agent used is not particularly limited, but is selected so that the molecular weight of the chloroprene polymer (or the Mooney viscosity of the chloroprene rubber obtained by isolating the polymer) is appropriate. Although it varies depending on the structure of the alkyl group and the target molecular weight, it is generally 0.05 to 5.0 parts by weight, preferably 0.1 to 0.5 parts by weight with respect to 100 parts by weight of the chloroprene monomer. Used.

  In order to complete the emulsion polymerization, a polymerization inhibitor may be added according to a conventional method. The polymerization inhibitor is not particularly limited as long as it is generally used in the production of chloroprene rubber. For example, phenothiazine, diethylhydroxylamine, hydroquinone, t-butylcatechol, 1,3,5-trihydroxybenzene, Hydroquinone methyl ether can be used.

  Among these, when using a water-insoluble one, it may be used as an aqueous emulsion in the presence of a surfactant after being dissolved in chloroprene or an organic solvent.

  As a method for isolating the polymer from the latex after the completion of the emulsion polymerization, any generally known method such as a freeze coagulation method, a salting out method, a method using an extruder, etc. may be used. A coagulation method is used.

  The chloroprene rubber of the present invention has an average branching index gM of 1.00 to 1.12. If it is less than 1.00, the brush coatability is lowered. When it is larger than 1.12, sufficient layer separation resistance cannot be obtained.

  The average branching index gM is an index representing whether the polychloroprene chain is linear or non-linear. The lower the gM value, the higher the degree of branching of the polymer chain, indicating a non-linear state. In the present invention, chloroprene rubber is relatively compared using a linear polystyrene as a reference polymer (refer to Examples for the reference polymer and measurement method). The definition of gM and the measurement principle are described in JP-A-2005-220349.

  In order to lower the gM value of chloroprene rubber, the degree of branching of the chloroprene rubber may be increased. For example, the polymerization rate during emulsion polymerization of chloroprene is increased, the polymerization temperature is increased, and the molecular weight is increased. Adjust it.

  The chloroprene rubber of the present invention preferably has a Mooney viscosity of 55 to 100 ML (1 + 4) 100 ° C. If it is less than 55, the amount of chloroprene rubber used to bring the solution viscosity of the adhesive into the use range may increase. If it is greater than 100, the dissolution time of the adhesive may become longer.

  The chloroprene rubber of the present invention is also characterized by good brush coatability when an adhesive obtained by using the rubber is spread on an adherend. Brush coatability is measured by measuring the maximum height of the toluene solution rising in the glass tube when a glass tube with an inner diameter of 6 mm is submerged 30 mm in a 10% toluene solution of chloroprene rubber adjusted to 20 ° C. and rotated at 2000 rpm for 30 seconds. You can evaluate it. If a chloroprene rubber having a height exceeding 10 mm is used as an adhesive, workability when applied to an adherend with a brush may deteriorate. Moreover, since it becomes wavy when it is spread and the thickness of the adhesive layer becomes non-uniform, there are cases where sufficient adhesive strength cannot be obtained.

  In order to reduce the maximum height of the toluene solution rising in the glass tube, the degree of branching of the chloroprene rubber may be reduced. For example, the polymerization rate during emulsion polymerization of chloroprene may be reduced, or the polymerization temperature may be kept low. The molecular weight may be adjusted to be small.

  The chloroprene rubber of the present invention can be made into an adhesive by dissolving it in an organic solvent and mixing commonly used additives such as metal oxides, tackifying resins, and antioxidants. The mixing method is not particularly limited, but the so-called “kneading method” in which chloroprene rubber is kneaded using a kneader such as an open roll and mixed with a chemical such as a metal oxide, without using a kneader, Any method of the so-called “direct solution method” in which the compounding chemical is directly dissolved in an organic solvent may be used.

  The solvent used in the solvent-based adhesive of the present invention is not an aromatic solvent such as toluene, xylene, or ethylbenzene that causes sick house syndrome, but n-hexane, cyclohexane, methylcyclohexane, acetone, methyl ethyl ketone, ethyl acetate, acetic acid. It is preferable to dissolve the chloroprene rubber only with a mixture of poor solvents which are non-aromatic solvents such as butyl and are poor in solubility of the chloroprene rubber alone.

  When preparing a solvent-type adhesive, it is preferable to add a tackifier resin. The tackifying resin used in this case is not particularly limited, and any tackifying resin generally used for solvent-based adhesives can be used. Specifically, alkylphenol resin, rosin resin, rosin ester, polymerized rosin resin, hydrogenated rosin resin, polyterpene resin, α-pinene resin, β-pinene resin, terpene phenol resin, C5 fraction petroleum resin, C9 fraction Examples include petroleum petroleum resins, C5 / C9 fraction petroleum resins, dicyclopentadiene petroleum resins, xylene resins, coumarone resins, coumarone-indene resins, and the like. From the viewpoint of adhesive properties, it is particularly preferable to use an alkylphenol resin.

  Although the compounding quantity of tackifying resin is not specifically limited, 10-100 mass parts is preferable with respect to 100 mass parts of chloroprene rubber, and 20-80 mass parts is more preferable. More preferably, it is 30-70 mass parts.

Moreover, it is also preferable to mix | blend a metal oxide with a solvent type adhesive agent in order to capture the hydrochloric acid generated when a chloroprene rubber deteriorates over time, or to cause a chelating reaction with an alkylphenol resin.
Examples of the metal oxide include magnesium oxide, zinc oxide, and calcium oxide, but are not limited thereto. In the adhesive of the present invention, it is preferable to use magnesium oxide and zinc oxide in combination because the viscosity stability during storage of the adhesive is good.
The compounding amount of the metal oxide is not particularly limited, but is preferably 0.5 to 15 parts by mass and more preferably 2 to 10 parts by mass with respect to 100 parts by mass of the chloroprene rubber.

  In addition to the above, the chloroprene rubber adhesive includes fillers, ultraviolet absorbers, antioxidants, silane coupling agents, chlorinated rubber, chlorinated polyethylene, colorants, curing agents, etc., in accordance with the required performance. It can be added arbitrarily.

  The chloroprene rubber of the present invention may be used for graft paste. Graft glue is a solvent that uses modified chloroprene rubber that is obtained by dissolving chloroprene rubber in a solvent such as toluene or methyl ethyl ketone, adding a monomer such as methyl methacrylate, and graft polymerization using a polymerization initiator such as benzoyl peroxide. It is a mold adhesive and is useful for bonding soft PVC materials.

  Hereinafter, the effects of the present invention will be described in detail with reference to Examples and Comparative Examples, but these Examples do not limit the present invention. In the following description, unless otherwise specified, parts and% are expressed on a mass basis.

[Example 1]
[Production of chloroprene rubber]
Using a reactor having an internal volume of 5 liters, 12 parts of disproportionated rosin acid potassium salt Longis K-25 (manufactured by Arakawa Chemical Industries) in 100 parts of pure water under a nitrogen atmosphere, a condensate of naphthalenesulfonic acid and formaldehyde 0.5 parts of sodium salt (trade name Demol N: manufactured by Kao) and 0.3 parts of sodium hydroxide were dissolved. In this solution, 100 parts of chloroprene and 0.12 part of dodecyl mercaptan were added and emulsified, and then emulsion polymerization was performed at 10 ° C. in a nitrogen atmosphere using potassium persulfate as an initiator. When the polymerization rate of chloroprene reached 75%, phenothiazine emulsion was added to terminate the polymerization. Subsequently, it heated under reduced pressure and collect | recovered unreacted chloroprene. The obtained polychloroprene latex was adjusted to pH 7 with dilute acetic acid, and then made into a sheet by a conventional freeze coagulation method, which was dried to obtain chloroprene rubber. Table 1 shows the average branching index gM, Mooney viscosity ML (1 + 4) 100 ° C., and results of the brush coatability test.

[Adjustment of average branching index gM measurement sample]
As the linear polymer, Tosoh standard polystyrene F-128 (Mw = 1.09 million, Mw / Mn = 1.08) and Tosoh standard polystyrene F288 (Mw = 2.88 million, Mw / Mn = 1.09), respectively. 20 mg was measured, mixed, and dissolved in 20 ml of THF (special grade, 99.5%, manufactured by Wako Chemical Industry Co., Ltd.) at 23 ° C. to obtain a standard solution. 40 mg of chloroprene rubber was dissolved in 20 ml of special grade THF (manufactured by Wako Chemical Co., Ltd.) at 23 ° C. to prepare a 0.2% THF solution of chloroprene rubber. The solution was filtered through a 0.5 μm filter to obtain a measurement sample.

[Measurement of average branching index gM]
The average branching index gM was measured by GPC-MALLS. MALLS was performed using DAWN-DSP-F manufactured by Wyatt Technology, a pump using DS-4 manufactured by Shodex, and an RI detector using RI-71 manufactured by Shodex. The separation column was TSKgel GMHHR-H (30), and the flow rate was 1 ml / min, the column temperature was 23 ° C., and the injection volume was 200 μl. As a standard, polystyrene standard (Mw = 30,300, Mw / Mn = 1.0) manufactured by GL Sciences Inc. was used.
Data processing is performed by analysis software ASTRA manufactured by Wyatt Technology, and the correlation between the ratio of the rotational square radius of the measurement sample to the reference sample and the molecular weight is calculated. The average branching index in the weight average molecular weight range of 100 to 1,500,000 is defined as gM.

[Measurement of average branching index gM (reference)]
In this patent, polystyrene, which is easily available and stable in quality, was used as a standard substance. Since polystyrene and polychloroprene have different chemical structures, the average branching index gM of polychloroprene measured using polystyrene as a standard substance may exceed 1.00.
As reference data, Tables 1 and 2 show the average branching index gM (reference) obtained by GPC-MALLS measurement using the chloroprene polymer of Comparative Example 1 as a standard.

[Measurement of Mooney viscosity]
About the chloroprene rubber, the Mooney viscosity in 100 degreeC was measured based on JIS-K6300.

[Evaluation of brush coatability]
17 g of chloroprene rubber and 153 g of toluene are mixed and stirred until the chloroprene rubber is completely dissolved to obtain a 10% toluene solution of chloroprene rubber. A transparent glass tube with an inner diameter of 6 mm was submerged 30 mm in the test solution adjusted to 20 ° C. and rotated at 2000 rpm for 30 seconds. Based on the liquid level, the maximum height of the 10% toluene solution rising in the glass tube was measured with a caliper.

[Adhesive adjustment]
An alkylphenol resin (Tamanol 526: manufactured by Arakawa Chemical Industries) and 3 parts of magnesium oxide (Kyowa Mag # 150: manufactured by Kyowa Chemical Industry Co., Ltd.) were dissolved in 100 parts of cyclohexane and subjected to a chelation reaction at room temperature for 16 hours. Next, 100 parts of chloroprene rubber, 1 part of 2,6-di-t-butyl-4-methylphenol (NOCRACK 200: manufactured by Ouchi Shinsei Chemical Co., Ltd.), 3 parts of magnesium oxide, and oxidation with respect to the cyclohexane solution 1 part of zinc, 180 parts of cyclohexane, 75 parts of n-hexane, 120 parts of acetone and 55 parts of isopropyl acetate were added and mixed and stirred until the chloroprene rubber was completely dissolved to obtain an adhesive. Table 1 shows the results of the viscosity, delamination resistance and peel strength of the adhesive.

[Measurement of viscosity of adhesive]
After creating the adhesive, the viscosity at 25 ° C. was measured using a Brookfield viscometer.

[Adhesive layer separation resistance test]
The adhesive was placed in a glass container and stored in a constant temperature water bath at 60 ° C. under light shielding. The appearance of the adhesive was observed over 8 weeks, and the week in which separation of the adhesive components was observed was recorded.

[Peel strength]
The peel strength test was performed according to the method defined in JIS K 6854-3: 1999, using canvas as the adherend. The obtained adhesive is applied to the canvas with a brush so that the application amount is about 300 g / m ² , and is left for 30 minutes after the final application, and then the adhesive-coated surfaces of the canvas are bonded together. And crimped. The laminated sample was cured at 23 ° C. for 7 days, then cut to a size of 200 × 25 mm, and a T-type peel test was performed at a rate of 200 mm / min in an atmosphere at 23 ° C.

[Example 2]
Polymerization was carried out under the same conditions as in Example 1, except that dodecyl mercaptan was 0.11 part and the polymerization rate was 73%. The adhesive was adjusted under the conditions of Example 1 except that the solvent added after the chelate reaction was 203 parts cyclohexane, 81 parts n-hexane, 130 parts acetone, and 60 parts isopropyl acetate. Table 1 shows the results of average branching index gM, Mooney viscosity ML (1 + 4) 100 ° C., brush coatability test, adhesive viscosity, delamination resistance, and peel strength.

[Example 3]
Polymerization was carried out under the same conditions as in Example 1, except that dodecyl mercaptan was 0.13 part and the polymerization rate was 79%. The adhesive was adjusted under the conditions of Example 1 except that the solvent added after the chelation reaction was 157 parts of cyclohexane, 69 parts of n-hexane, 110 parts of acetone, and 51 parts of isopropyl acetate. Table 1 shows the results of average branching index gM, Mooney viscosity ML (1 + 4) 100 ° C., brush coatability test, adhesive viscosity, delamination resistance, and peel strength.

[Example 4]
Polymerization was carried out under the same conditions as in Example 1 except that dodecyl mercaptan was 0.18 part and the polymerization temperature was 30 ° C. The adhesive was adjusted under the conditions of Example 1 except that the solvent added after the chelation reaction was 157 parts of cyclohexane, 69 parts of n-hexane, 110 parts of acetone, and 51 parts of isopropyl acetate. Table 1 shows the results of average branching index gM, Mooney viscosity ML (1 + 4) 100 ° C., brush coatability test, adhesive viscosity, delamination resistance, and peel strength.

[Example 5]
Polymerization was carried out under the same conditions as in Example 1 except that 97 parts of chloroprene and 3 parts of 2,3-dichloro-1,3-butadiene were used. The adhesive was adjusted under the conditions of Example 1. Table 1 shows the results of average branching index gM, Mooney viscosity ML (1 + 4) 100 ° C., brush coatability test, adhesive viscosity, delamination resistance, and peel strength.

[Example 6]
Polymerization was carried out under the same conditions as in Example 1 except that dodecyl mercaptan was 0.16 part and the polymerization rate was 85%. The adhesive was adjusted under the conditions of Example 1 except that the solvent added after the chelation reaction was 70 parts cyclohexane, 31 parts n-hexane, 49 parts acetone, and 23 parts isopropyl acetate. Table 1 shows the results of average branching index gM, Mooney viscosity ML (1 + 4) 100 ° C., brush coatability test, adhesive viscosity, delamination resistance, and peel strength.

[Example 7]
Polymerization was carried out under the same conditions as in Example 1 except that the dodecyl mercaptan was 0.09 part and the polymerization rate was 63%. The adhesive was adjusted under the conditions of Example 1 except that the solvent added after the chelation reaction was 235 parts of cyclohexane, 103 parts of n-hexane, 165 parts of acetone, and 76 parts of isopropyl acetate. Table 1 shows the results of average branching index gM, Mooney viscosity ML (1 + 4) 100 ° C., brush coatability test, adhesive viscosity, delamination resistance, and peel strength.

[Example 8]
Polymerization was carried out under the same conditions as in Example 1 except that dodecyl mercaptan was 0.10 parts and the polymerization rate was 85%. The adhesive was adjusted under the conditions of Example 1 except that the solvent added after the chelate reaction was 203 parts cyclohexane, 81 parts n-hexane, 130 parts acetone, and 60 parts isopropyl acetate. Table 1 shows the results of average branching index gM, Mooney viscosity ML (1 + 4) 100 ° C., brush coatability test, adhesive viscosity, delamination resistance, and peel strength.

[Comparative Example 1]
Polymerization was carried out under the same conditions as in Example 1 except that 0.11 part of dodecyl mercaptan and the polymerization rate were 68%. The adhesive was blended under the conditions of Example 1. Table 2 shows the results of average branching index gM, Mooney viscosity ML (1 + 4) 100 ° C., brush coatability test, adhesive viscosity, delamination resistance, and peel strength.

[Comparative Example 2]
Polymerization was carried out under the same conditions as in Example 1, except that 0.14 part of dodecyl mercaptan and the polymerization rate were 80%. The adhesive was blended under the same conditions as in Example 1 except that the solvent added after the chelate reaction was 192 parts of cyclohexane, 78 parts of n-hexane, 125 parts of acetone, and 57 parts of isopropyl acetate. Table 2 shows the results of average branching index gM, Mooney viscosity ML (1 + 4) 100 ° C., brush coatability test, adhesive viscosity, delamination resistance, and peel strength.

[Comparative Example 3]
Polymerization was performed under the same conditions as in Example 1 except that 0.10 parts of dodecyl mercaptan, a polymerization temperature of 30 ° C., and a polymerization rate of 70%. The adhesive was blended under the conditions of Example 1 except that the solvent added after the chelate reaction was 151 parts of cyclohexane, 66 parts of n-hexane, 108 parts of acetone, and 47 parts of isopropyl acetate. Table 2 shows the results of average branching index gM, Mooney viscosity ML (1 + 4) 100 ° C., brush coatability test, adhesive viscosity, delamination resistance, and peel strength.

[Comparative Example 4]
Polymerization was carried out under the same conditions as in Example 1 except that 97 parts of chloroprene, 3 parts of 2,3-dichloro-1,3-butadiene and a polymerization rate of 68% were obtained. The adhesive was adjusted under the conditions of Example 1. Table 2 shows the results of average branching index gM, Mooney viscosity ML (1 + 4) 100 ° C., brush coatability test, adhesive viscosity, delamination resistance, and peel strength.

Claims (1)

The average branching index gM at a weight average molecular weight of 1,000,000 to 1,500,000 using linear polystyrene as a reference polymer, measured using a gel permeation chromatograph-multi-angle laser light scattering detector (GPC-MALLS) is 1. 00 to 1.12 der is, Mooney viscosity, a 55~100ML (1 + 4) 100 ℃ , 10% toluene solution of chloroprene rubber adjusted to 20 ° C., at 2000rpm submerged 30mm transparent glass tube having an inner diameter of 6mm An adhesive obtained by dissolving chloroprene rubber in a non-aromatic solvent, wherein the maximum height of the toluene solution rising in the glass tube is 10 mm or less when rotated for 30 seconds.