JP2006199933A - Chloroprene polymer composition and adhesive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chloroprene polymer composition and an adhesive composition without readily discoloring with light or heat. <P>SOLUTION: The chloroprene polymer composition comprises a chloroprene polymer, a benzotriazole ultraviolet light absorber, a hindered amine light stabilizer and a phenolic antioxidant. The benzotriazole ultraviolet light absorber is preferably at least one kind selected from 5-chloro-2-(3-tert-butyl-2-hydroxy-5-methylphenyl)benzotriazole or 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole. The hindered amine light stabilizer is preferably at least one kind selected from bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate or bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a chloroprene polymer composition and an adhesive composition.

Chloroprene polymers are used in various applications because they have a good balance of physical properties such as mechanical properties, deterioration resistance, and chemical resistance, and adhesives are one of their typical applications. Chloroprene polymers are used for various adherends because they exhibit good adhesion to many adherends (see, for example, Non-Patent Document 1).
Adhesion technology Vol. 21, no. 4 (2002) No. 65 (4th page; Section 1.3 (2), 2nd paragraph) However, chloroprene polymer has the disadvantage of being colored yellow or brown when exposed to heat or light. Depending on the application, use may be restricted due to the discoloration. Therefore, improvement of the discoloration resistance of the chloroprene polymer is demanded, and for example, techniques described in Patent Documents 1 to 3 are known. However, in any case, the effect of improving discoloration resistance is insufficient, and further improvement has been demanded. JP-A-5-93094 (second page; claims 1, fourth page; example 1) JP-A-7-207070 (second page; claims 1, third page; example 1) Japanese Patent Laid-Open No. 11-21317 (second page; claims 1, page 6; Examples 1 to 11)

  An object of the present invention is to provide a chloroprene polymer composition and an adhesive composition that are less discolored even when exposed to heat or light.

  Chloroprene polymer, benzotriazole UV absorber, hindered amine light stabilizer, chloroprene polymer composition containing phenolic antioxidant, and adhesion containing this chloroprene polymer composition and organic solvent The above problems can be solved by the agent composition.

  Even if the chloroprene polymer composition and adhesive composition of the present invention are exposed to heat and light, a chloroprene polymer composition and adhesive composition with little discoloration can be obtained.

The chloroprene polymer is a homopolymer of 2-chloro-1,3-butadiene (hereinafter referred to as chloroprene) or a copolymer of chloroprene and a monomer copolymerizable with chloroprene.
The chloroprene polymer of the present invention also includes a graft copolymer obtained by graft polymerization of another monomer to the chloroprene polymer.

  Examples of the monomer copolymerizable with chloroprene include 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, butadiene, isoprene, styrene, acrylonitrile, acrylic acid, and esters thereof. Methacrylic acid or esters thereof, and two or more types can be used in combination as required.

  The chloroprene polymer is not particularly limited, but the molecular weight is determined by appropriately selecting and controlling the polymerization temperature, polymerization initiator, chain transfer agent, polymerization terminator, final polymerization rate, etc. when polymerizing chloroprene. , Molecular weight distribution, molecular terminal structure, crystallization speed and the like can be arbitrarily adjusted.

The method for polymerizing chloroprene is not particularly limited, but a method by emulsion polymerization according to a conventional method is simple and preferable from the viewpoint of performance.
The emulsifier and the dispersant used for the emulsion polymerization are not particularly limited, but those commonly used can be used. Examples of the emulsifier and dispersant include rosin acid or an alkali metal salt of rosin acid, alkylbenzene sulfonic acid, a condensate of naphthalene sulfonic acid and formalin, and alkyl diphenyl ether sulfonic acid.
In the present invention, since the color tone of the chloroprene polymer itself is also important, it is advantageous to use an emulsifier / dispersant with as little coloring as possible, and rosin acid and alkyldiphenyl ether disulfonic acid having a Gardner color number of 4 or less. It is particularly preferred to use a combination of

（ここで、Ｒは水素、アルキル基、又はアラルキル基を、Ｘはハロゲンまたは水素を表す）

（ここで、Ｒは水素、アルキル基、又はアラルキル基を、Ｘはハロゲンまたは水素を表す）
耐変色性改良効果の観点からは、特に、５−クロロ−２−（３−ｔｅｒｔ−ブチル−２−ヒドロキシ−５−メチルフェニル）ベンゾトリアゾールや２−（２’−ヒドロキシ−３’，５’−ジ−ｔｅｒｔ−アミルフェニル）ベンゾトリアゾールを使用することが好ましい。
ベンゾトリアゾール系紫外線吸収剤の添加量は、効果の発現や得られる接着剤組成物の接着物性を向上させるという観点から、クロロプレン重合体１００質量部に対して０．０１〜１０質量部が好ましく、０．１〜５質量部がより好ましい。 The benzotriazole ultraviolet absorber is a compound having a functional group having a structure represented by the general formula (Chemical Formula 1) or the general formula (Chemical Formula 2).

(Where R represents hydrogen, an alkyl group, or an aralkyl group, and X represents halogen or hydrogen)

(Where R represents hydrogen, an alkyl group, or an aralkyl group, and X represents halogen or hydrogen)
From the viewpoint of the effect of improving discoloration resistance, in particular, 5-chloro-2- (3-tert-butyl-2-hydroxy-5-methylphenyl) benzotriazole and 2- (2′-hydroxy-3 ′, 5 ′) It is preferred to use -di-tert-amylphenyl) benzotriazole.
The addition amount of the benzotriazole-based ultraviolet absorber is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the chloroprene polymer from the viewpoint of expression of effects and improvement of the adhesive properties of the obtained adhesive composition. 0.1-5 mass parts is more preferable.

（ここで、Ｒは水素、アルキル基、またはアラルキル基を表す）
耐変色性改良効果の観点からは、特に、ビス（２，２，６，６−テトラメチル−４−ピペリジル）セバケートやビス（１，２，２，６，６−ペンタメチル−４−ピペリジル）セバケートを使用することが好ましい。 The hindered amine light stabilizer is a compound having a functional group having a structure represented by the general formula (Formula 3).

(Where R represents hydrogen, an alkyl group, or an aralkyl group)
From the viewpoint of the effect of improving discoloration resistance, in particular, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate and bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate Is preferably used.

A phenolic antioxidant is an organic compound having a phenol structure in the molecule and having antioxidant performance.
In particular, 2,2′-methylenebis (4-ethyl-6-tert-butylphenol) or 2,2′-methylenebis (4-methyl-6-tert-butylphenol) is used from the viewpoint of the effect of improving discoloration resistance. It is preferable.

From the viewpoint of the effect of improving discoloration resistance and adhesive strength, the total amount of benzotriazole-based ultraviolet absorber, hindered amine-based light stabilizer, and phenol-based antioxidant is 0.02 to 11 mass per 100 mass parts of chloroprene polymer. Part is preferred. More preferably, it is 0.5-5 mass parts, More preferably, it is 0.2-3 mass parts.
Moreover, the compounding ratio of these compounds is not particularly specified, but preferably in the range of 1 to 95%. More preferably, each is in the range of 5 to 70%, more preferably 10 to 50%.

The organic solvent used for preparing the adhesive composition is not particularly limited, but for example, literature such as HANDBOOK OF ADHESIVES (1993) (pages 214 to 215), published by Asakura Shoten, etc. May be appropriately selected in consideration of the solubility of the chloroprene polymer described in the above. A polar solvent and a nonpolar solvent may be used in an appropriate combination instead of the chloroprene polymer parent solvent.
The organic solvent is not particularly limited, for example, toluene, xylene, chlorobenzene, methylene chloride, chloroform, carbon tetrachloride, tetrachloroethane, pentane, hexane, heptane, octane, isooctane, nonane, decane, cyclohexane, Cycloheptane, methylcyclopentane, methylcyclohexane, tetrahydronaphthalene, industrial gasoline, acetone, methyl ethyl ketone, diethyl ketone, methyl butyl ketone, diisobutyl ketone, cyclohexanone, cyclopentanone, ethyl acetate, propyl acetate, butyl acetate, octyl acetate, butyl There are propionate, diethyl ether, tetrahydrofuran, N, N-dimethylformamide and the like.
The blending amount of the organic solvent is not particularly limited, but is preferably an amount in which the solid content of the adhesive on the mass basis is in the range of 5 to 50% from the viewpoint of workability and not causing poor adhesion. The range which becomes 10 to 40% is more preferable, and the range which becomes 15 to 30% is still more preferable.

  In addition to the above, the adhesive composition includes a tackifying resin, a filler, an ultraviolet absorber, an antioxidant, a silane coupling agent, a chlorinated rubber, a chlorinated polyethylene, a curing agent, according to the required performance. Metal oxides other than magnesium oxide and zinc oxide can be optionally added.

  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, parts and% are expressed on a mass basis unless otherwise specified.

Example 1
[Polymerization of chloroprene polymer]
Using a reactor having an internal volume of 5 liters, 4 parts of disproportionated rosin acid (trade name Longis FR: manufactured by Arakawa Chemical Co., Ltd.) having a Gardner color number of 4 or less in 110 parts of pure water under a nitrogen atmosphere, alkyl diphenyl ether disulfone 0.5 parts of sodium acid (trade name Perex SS-H: manufactured by Kao), 0.8 part of sodium hydroxide and 0.5 part of sodium bisulfite were dissolved. 100 parts of chloroprene monomer and 0.12 parts by weight of dodecyl mercaptan were added to this solution for emulsification, and then emulsion polymerization was performed at 10 ° C. in a nitrogen atmosphere using sodium sulfite and potassium persulfate as initiators. When the monomer addition rate reached 70%, phenothiazine emulsion was added to terminate the polymerization.
Subsequently, 0.2 part of 5-chloro-2- (3-tert-butyl-2-hydroxy-5-methylphenyl) benzotriazole (trade name Tinuvin 326: manufactured by Ciba Specialty Chemicals), bis (2,2, 6,6-tetramethyl-4-piperidyl) sebacate (trade name Tinuvin 770, manufactured by Ciba Specialty Chemicals), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol) (commodity) (Name: NOCRACK NS-5: Ouchi Shinsei Chemical Co., Ltd.) After adding 0.2 part of the emulsion, the mixture was heated under reduced pressure to recover the unreacted monomer.
The obtained latex of the chloroprene polymer was adjusted to pH 7 with dilute acetic acid, then made into a sheet by a conventional freeze coagulation method, and dried to obtain a sheet of a chloroprene polymer composition.

≪Light discoloration resistance test≫
A test piece having a length of about 30 mm, a width of about 30 mm, and a thickness of about 5 mm was prepared from the obtained sheet of the chloroprene polymer composition. This was used as a test piece for a light discoloration resistance test, and a light discoloration resistance test was performed with a xenon light resistance tester (WEL-75X-HC.B.EC manufactured by Suga Test Instruments Co., Ltd.).
The test piece was a ceramic white plate (L * = 92.62, a * = 0.14, b * = 2.95) using a multi-light source spectrocolorimeter Multi Spectro Color Meter (manufactured by Suga Test Instruments Co., Ltd.). The color difference (ΔE) was measured and the degree of discoloration was compared. The results are shown in Table 1.

≪Heat-resistant discoloration test≫
A test piece having a length of about 30 mm, a width of about 30 mm, and a thickness of about 5 mm was prepared from the obtained sheet of the chloroprene polymer composition. This was stored in a gear oven at 70 ° C. as a test piece for heat discoloration test.
Similarly to the light discoloration resistance test, the test piece was made of a ceramic standard white plate (L * = 92.62, a * = 0.14) using a multi-light source spectrocolorimeter Multi Spectro Color Meter (manufactured by Suga Test Instruments Co., Ltd.). b * = 2.95) and the color difference (ΔE) was measured, and the degree of discoloration was compared. The results are shown in Table 1.

Examples 2-7
Except that the ultraviolet absorber, hindered amine, and antioxidant used in Example 1 were changed as shown in Table 1, tests were conducted in the same manner as in Example 1 to obtain Examples 2 to 7.

Comparative Examples 1-5
A test was conducted in the same manner as in Example 1 except that the ultraviolet absorber, hindered amine, and antioxidant used in Example 1 were changed as shown in Table 1, and Comparative Examples 1 to 5 were obtained.

Example 8
[Graft polymerization]
In a glass reactor in which a stirring blade and a condenser were set, 100 parts of chloroprene monomer (Electrochemical Industry A-90S) was dissolved in a mixed solvent of 400 parts of toluene and 200 parts of methyl ethyl ketone. Subsequently, 50 parts of methyl methacrylate was added and it hold | maintained at 80 degreeC in air atmosphere.
0.5 parts of benzoyl peroxide was added as a polymerization initiator, and the grafting reaction was started with stirring. When the reaction was allowed to proceed for 5 hours, 2.0 parts of BHT was added to terminate the polymerization. The conversion rate of methyl methacrylate was 43%.
0.5 parts of 5-chloro-2- (3-tert-butyl-2-hydroxy-5-methylphenyl) benzotriazole (trade name Tinuvin 326: manufactured by Ciba Specialty Chemicals) Bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate (trade name Tinuvin 770, manufactured by Ciba Specialty Chemicals), 0.5 part of 2,2′-methylenebis (4-ethyl-6- tert-butylphenol) (trade name: NOCRACK NS-5: manufactured by Ouchi Shinsei Chemical Co., Ltd.) 1.0 part was added to obtain a graft adhesive.

≪Light discoloration resistance test of graft adhesive≫
The obtained graft adhesive was applied to a filter paper at a coating amount of 300 g / m ² and dried in a dark place for 5 days to obtain a test piece. The test piece was subjected to a light discoloration resistance test using a xenon light resistance tester (WEL-75X-HC.B.EC manufactured by Suga Test Instruments Co., Ltd.).
The test piece was a ceramic white plate (L * = 92.62, a * = 0.14, b * = 2.95) using a multi-light source spectrocolorimeter Multi Spectro Color Meter (manufactured by Suga Test Instruments Co., Ltd.). The color difference (ΔE) was measured and the degree of discoloration was compared. The results are shown in Table 2.

Examples 9-11
Except that the ultraviolet absorber, hindered amine, and antioxidant used in Example 8 were changed as shown in Table 2, tests were conducted in the same manner as in Example 8 to obtain Examples 9 to 11.

Comparative Examples 6-9
A test was performed in the same manner as in Example 8 except that the ultraviolet absorber, hindered amine, and antioxidant used in Example 8 were changed as shown in Table 2, and Comparative Examples 6 to 9 were obtained.

  As can be seen from Table 1 and Table 2 that summarize the results of Examples and Comparative Examples, all Examples have excellent discoloration resistance, whereas Comparative Examples have light discoloration resistance and heat discoloration resistance. Insufficient. It can be seen that the discoloration resistance is greatly improved by the present invention.

  The chloroprene polymer of the present invention has excellent discoloration resistance and can be used for various applications. Especially in adhesive applications, since there is little discoloration, it can also be applied to applications that have been limited to discoloration until now. Paper, wood, cloth, leather, rubber, It is suitably used for bonding various materials such as plastics, earthenware, ceramics, glass, mortar, cement, and metals.

In Tables 1 and 2, Tinuvin 326 (trade name) is 5-chloro-2- (3-tert-butyl-2-hydroxy-5-methylphenyl) benzotriazole, Tinuvin 328 (trade name) is 2- (2 '-Hydroxy-3', 5'-di-tert-amylphenyl) benzotriazole, Tinuvin P (trade name) is 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, Sumisorb 130 (trade name) Represents 2-hydroxy-4-octoxybenzophenone. Tinuvin 770 (trade name) is bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, and tinuvin 765 (trade name) is bis (1,2,2,6,6-pentamethyl-4). -Piperidyl) sebacate, Tinuvin 144 (trade name) is bis (1,2,2,6,6-) of 2- (3,5-di-tert-butyl-4-hydroxybenzyl) -2-n-butylmalonate Pentamethyl-4-piperidyl) and Adekastab LA-52 (trade name) represent 1,2,2,6,6-pentamethyl-4-piperidyl-1,2,3,4-butanetetracarboxylate.
Furthermore, Nocrack NS-5 (trade name) is 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), Nocrack NS-6 (trade name) is 2,2'-methylenebis (4-methyl-6) -Tert-butylphenol), Irganox 1010 (trade name) is pentaerythritol tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), and Sumilizer BHT (trade name) is 2,6- Di-t-butyl-4-methylphenol is represented.

Claims (7)

  A chloroprene polymer composition comprising a chloroprene polymer, a benzotriazole ultraviolet absorber, a hindered amine light stabilizer, and a phenolic antioxidant.   The benzotriazole-based UV absorber is 5-chloro-2- (3-tert-butyl-2-hydroxy-5-methylphenyl) benzotriazole or 2- (2′-hydroxy-3 ′, 5′-di-tert The chloroprene polymer composition according to claim 1, which is at least one selected from -amylphenyl) benzotriazole.   The hindered amine light stabilizer is at least one selected from bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate or bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate The chloroprene polymer composition according to claim 1 or 2, wherein:   The phenolic antioxidant is at least one selected from 2,2′-methylenebis (4-ethyl-6-tert-butylphenol) or 2,2′-methylenebis (4-methyl-6-tert-butylphenol). The chloroprene polymer composition according to any one of claims 1 to 3, wherein:   The chloroprene polymer is obtained by emulsion polymerization in the presence of a rosinate having a Gardner color number of 4 or less and an alkyl diphenyl ether disulfonate, according to any one of claims 1 to 4, The described chloroprene polymer composition. The chloroprene polymer composition according to any one of claims 1 to 5, wherein the chloroprene polymer is a graft copolymer of 2-chloro-1,3-butadiene and methyl methacrylate. An adhesive composition comprising the chloroprene polymer composition according to any one of claims 1 to 6 and an organic solvent.