JP3426481B2 - Chloroprene rubber composition and adhesive using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a chloroprene rubber composition suitable for an adhesive and an adhesive using the same. More specifically, the present invention relates to a chloroprene-based rubber composition and an adhesive using the same, which gives an adhesive having a significantly suppressed discoloration after storage in a metal container such as a tin can.

[0002]

2. Description of the Related Art Chloroprene rubber-based adhesives are manufactured by adding aging inhibitors, metal oxides, tackifying resins, solvents, etc. to chloroprene rubber, which is a raw material rubber, and chloroprene for difficult-to-adhere materials. It is known to use a rubber graft-polymerized with methyl methacrylate (hereinafter, this is often referred to as a chloroprene rubber adhesive).

However, when the chloroprene rubber-based adhesive thus prepared is stored in a metal container such as a tin can, the adhesive is discolored and the quality is deteriorated.

Up to now, various measures for suppressing discoloration due to light and heat have been reported (JP-A-5-93094, JP-A-7-207070, etc.), but the suppression of discoloration after storage in a tin container. There was no known effective countermeasure against.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a chloroprene rubber composition and a chloroprene using the same which, when stored in a metal container such as a tin can, provides an adhesive agent whose discoloration degree after storage is remarkably suppressed. An object is to provide a rubber-based adhesive.

[0006]

That is, the present invention provides a chloroprene rubber composition containing a chloroprene rubber and a compound having a piperidyl group in the molecule (hereinafter abbreviated as piperidyl group-containing compound) as essential components. And a chloroprene rubber composition containing a compound having at least two piperidyl groups in the molecule. Further, the chloroprene rubber is a chloroprene rubber composition which is a graft copolymer obtained by graft-polymerizing a methacrylic acid ester and / or an acrylic acid ester on the chloroprene rubber, and further an adhesive using them.
The graft copolymer of the present invention may contain a polymerization product such as a homopolymer of methacrylic acid ester or acrylic acid ester, which is a by-product in the graft polymerization.

The present invention will be described in detail below. The chloroprene rubber used in the present invention means 2-chloro-1,3-
It is a chloroprene copolymer composed of a homopolymer of butadiene (hereinafter referred to as chloroprene), 2-chloro-1,3-butadiene and a copolymerizable monomer. The chloroprene copolymer mentioned here includes a graft copolymer described later. Examples of the copolymerizable monomer include 2,
3-dichloro-1,3-butadiene, 1-chloro-1,
3-butadiene, sulfur, styrene, acrylonitrile,
Methacrylonitrile, isoprene, butadiene, methacrylic acid, acrylic acid and their esters can be used within a range that does not impair the inherent properties of chloroprene.

The polymerization of the chloroprene monomer alone or the mixture of the chloroprene monomer and the copolymerizable monomer is carried out in the presence of a radical initiator in an aqueous emulsion. The emulsifier for carrying out this aqueous emulsion polymerization is not particularly limited,
Emulsifiers generally used for emulsion polymerization of chloroprene, such as alkali metal salts of saturated or unsaturated fatty acids having 6 to 22 carbon atoms, rosin acid or disproportionated rosin acid, formalin of β-naphthalene sulfonic acid. An alkali metal salt of a condensate or the like is used. The polymerization temperature is preferably 0 to 55 ° C in consideration of the reactivity of the monomer. As the radical initiator, known organic peroxides such as potassium persulfate, ammonium persulfate, sodium persulfate, hydrogen peroxide and t-butyl hydroperoxide are used. Polymerization is performed at a conversion of 40 to 95%, preferably 50 to 85.
%, And then a small amount of a polymerization inhibitor is added to terminate the polymerization. Examples of the polymerization inhibitor include thiodiphenylamine, 4-tert-butylcatechol, 2,2-methylenebis-4-methyl-6-.
Tertiary butylphenol is used. The unreacted monomer is removed by, for example, a steam stripping method, and then the pH of the latex is adjusted to 5.5 to 7.
After adjusting to 5, the polymer can be isolated by conventional freeze-coagulation, washing with water, drying with hot air and the like.

Next, as a method for producing a graft copolymer by graft-polymerizing a methacrylic acid ester monomer and / or an acrylic acid ester monomer on chloroprene rubber which is one of the chloroprene rubbers of the present invention, For example, a methacrylic acid ester monomer and / or an acrylic acid ester monomer is added to a solution prepared by dissolving the chloroprene polymer or chloroprene copolymer obtained as described above in an organic solvent, in the presence of a radical initiator. A solution polymerization method in which chloroprene rubber is graft-polymerized with is generally used. An emulsion polymerization method in which a methacrylic acid ester monomer and / or an acrylic acid ester monomer is directly added to a latex of chloroprene rubber and graft polymerization is performed in the presence of a radical initiator can also be used. Examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and the like, and acrylic acid esters include methyl acrylate, ethyl acrylate,
Although there are propyl acrylate and the like, methyl methacrylate is preferably used from the viewpoint of reactivity.

As an example of the compound having a piperidyl group in the molecule used in the present invention, as the compound having one piperidyl group in the molecule, piperidine-2-carboxylic acid, piperidine-3-carboxylic acid, piperidine- 4-carboxylic acid, (2,2,6,6-tetramethyl-4-piperidyl) sebacic acid, (2,2,6,6-tetramethyl-4-piperidyl) azelaic acid, (2, 2, 6, 6-
Tetramethyl-4-piperidyl) adipic acid, (2,
2,6,6-Tetramethyl-4-piperidyl) oleic acid, (1,2,2,6,6-pentamethyl-4-piperidyl) sebacic acid, (1,2,2,6,6-pentamethyl-4) -Piperidyl) azelaic acid, (1,2,2,
6,6-pentamethyl-4-piperidyl) adipic acid,
Examples of compounds having (1,2,2,6,6-pentamethyl-4-piperidyl) oleic acid and the like and having two or more piperidyl groups in the molecule include bis (2,2,6,6).
-Tetramethyl-4-piperidyl) sebacate, bis (4-piperidyl) sebacate, bis (2,2,6,6)
-Tetramethyl-4-piperidyl) azelate, bis (4-piperidyl) azelate, bis (2,2,6,6)
-Tetramethyl-4-piperidyl) adipate, bis (4-piperidyl) adipate, bis (1,2,2,2
6,6-pentamethyl-4-piperidyl) sebacate,
Bis (1,2,2,6,6-pentamethyl-4-piperidyl) azelate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) adipate, 2- (3,5-
Di-t-butyl-4-hydroxybenzyl) -2-n-
Butyl malonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), N, N'-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1 , 2,2,6,6-Pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate, dimethyl succinate 1- (2-hydroxyethyl) -4-hydroxy-2 , 2,6,6-Tetramethylpiperidine polycondensate, poly [{6- (1,1,3,3
-Tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,
2,6,6-Tetramethyl-4-piperidyl) imino}] and the like.

As the method for incorporating the above-mentioned piperidyl group-containing compound into the chloroprene rubber, any method may be used as long as the piperidyl group-containing compound can be physically dispersed in the rubber, but one example is as follows.
Method of dispersing and adding to latex after completion of polymerization, method of dissolving chloroprene rubber and piperidyl group-containing compound in a common solvent and dispersing, passing through kneader such as extruder while heating chloroprene rubber, in the middle There is a method in which a piperidyl group-containing compound is added, dispersed and extruded.

The content of the piperidyl group-containing compound in the present invention is 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the chloroprene rubber. is there. When the content of the piperidyl group-containing compound is less than 0.01 part by weight, the effect of suppressing discoloration after storage in a tin can according to the present invention is not significantly exhibited, and when it exceeds 10 parts by weight, the cost is increased and it is economically disadvantageous.

To the chloroprene rubber-based adhesive according to the present invention, other additives, antioxidants, resins, stabilizers, plasticizers, solvents, etc. may be added within a range that does not impair the addition effect of the piperidyl group-containing compound. Well, one example is 2,
2'-methylene-bis- (4-ethyl-6-t-butylphenol), 2,2'-methylene-bis- (4-methyl-6-t-butylphenol), 2,2'-methylene-bis- ( 4-methyl-6-cyclohexylphenol), 4,4'-methylene-bis- (2,6-di-t-
Butylphenol), 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis- (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- ( 3,5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2
-(2-Hydroxy-3,5-di-t-butylphenol) -5-chlorobenzotriazole, 2- (2-hydroxy-3-t-butyl-5-methylphenol) -5
-Chlorobenzotriazole, 2- (3,5-di-t-
Amyl-2-hydroxyphenyl) benzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (2-
Examples include hydroxy-5-t-octylphenyl) benzotriazole, isopropenyltoluene resin, terpene-modified phenol resin, hydrogenated rosin resin, hydrogenated rosin ester resin, and aliphatic hydrocarbon resin.

[0014]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these. In the following description, parts and% are shown by weight.

Example 1 15 parts by weight of chloroprene rubber (Denkachloroprene A-90 manufactured by Denki Kagaku Kogyo Co., Ltd.) was dissolved in 85 parts by weight of toluene, and then the chemicals shown in Table 1 were added to obtain a uniform solution. A chloroprene rubber composition was prepared and used in the next storage test.

The degree of discoloration after storage in a tin can was determined as follows. As the tin can, a material tin can manufactured by Saitama Can Co., Ltd., which has a volume of 300 cc and is not coated with epoxy, is used. The toluene solution prepared in Example 1 was placed in a tin can, the lid was covered, and after heating at 70 ° C. for 2 days, changes in color tone and discoloration of the inner wall of the tin can were observed.
The color tone of the toluene solution is measured by the Lab method (reflection method) using a colorimetric color difference meter (model Σ80) manufactured by Nippon Denshoku Industries Co., Ltd.
The color difference ΔE was obtained from the measured values before and after storage, and the difference was evaluated. Changes in the inner wall of the tin can were visually observed.

A sample for adhesion test was prepared by further adding isopropenyltoluene resin (FTR-6 manufactured by Mitsui Petrochemical Co., Ltd.) to the above solution.
125) 20 parts by weight is added and dissolved, and isocyanate "Desmodur RFE" is added to 100 parts by weight of this solution.
After adding 5 parts by weight (made by Bayer Co., Ltd.) and stirring, 200 g / m ^{2 was} applied to the soft vinyl chloride leather as the adherend, and after 30 minutes of open time, they were joined and pressed back and forth 5 times with a 10-pound rubber roller. It was made. All operations were performed at room temperature. The adhesive strength is set time 7 using the above-mentioned bonded body.
After a day, the tensile strength was measured with a Tensilon tensile tester (manufactured by Shimadzu Corporation) at a tension rate of 50 mm / min.

Examples 2 to 5 After dissolving 100 parts by weight of chloroprene rubber in 600 parts by weight of toluene, methyl methacrylate (MMA) 75 was added.
After mixing 1 part by weight and raising the temperature to 85 ° C. with stirring, 0.5 part by weight of benzoyl peroxide was added and graft copolymerized for 5 hours, and then 0.5 part by weight of hydroquinone was added to terminate the polymerization reaction. Let

The chemicals shown in Table 1 were added to this graft copolymer (hereinafter referred to as graft copolymer A) solution to prepare a uniform solution, and a chloroprene rubber composition was prepared and used for the storage test. Evaluation items and evaluation methods are the same as in the first embodiment.
A sample for adhesion test was prepared by mixing 100 parts by weight of the graft copolymer with isopropenyltoluene resin and desmodur RFE in the same procedure as in Example 1 and applying the mixture to an adherend.

Examples 6 to 8 Using a reactor having an inner volume of 10 liters, 120 g of light-colored rosin acid (Longis FR manufactured by Arakawa Chemical Co., Ltd.), 30 g of sodium hydroxide, 30 g of a sodium salt of a naphthalenesulfonic acid formalin condensate, and distilled water. After adding 4000 g of a chloroprene monomer together with 5 g of n-dodecyl mercaptan to the soap solution adjusted to 4800 g and emulsifying the mixture, polymerization was carried out at 10 ° C. in a nitrogen atmosphere using potassium persulfate as a radical initiator. When the conversion reached 70%, an emulsion of phenothiazine was added as a polymerization inhibitor to terminate the polymerization. Then, the chemicals shown in Table 1 were dissolved in a concentration of 5% by weight with respect to the chloroprene monomer to prepare an emulsified solution, which was added and dispersed. Next, an unreacted monomer was removed by a conventional steam stripping method, and a chloroprene rubber composition was obtained from the obtained latex by a conventional freeze-drying coagulation method.

Using the chloroprene rubber composition thus obtained, a graft copolymer with MMA (referred to as graft copolymer B) was prepared in the same manner as in Examples 2-5.
Used for storage test. A sample for adhesion test was prepared by mixing 100 parts by weight of the graft copolymer with isopropenyltoluene resin and desmodur RFE in the same procedure as in Example 1 and applying the mixture to an adherend. The amounts of the chemicals (1), (3) and the benzotriazole compound described in Examples 6 to 8 in Table 1 are the amounts added as an emulsion after the above-mentioned termination of polymerization. is there.

[0022]

[Table 1]

In Table 1, the chemical (1) is N, N'-bis (3
-Aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3
5-triazine condensate, chemical (2) is piperidine-4-
Carboxylic acid, chemical (3) is 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-) Piperidyl). The benzotriazole compound a) of Example 3 is 2- (2′-hydroxy-3 ′, 5′-di-t
-Butylphenol) -5-chlorobenzotriazole, the benzotriazole compound b) of Example 8 is 2-
(3,5-di-t-amyl-2-hydroxyphenyl)
Benzotriazole.

Comparative Example 1 The results are shown in Table 2 in the case where the chemical according to the present invention was not added in Example 1.

Comparative Example 2 In Examples 2, 4 and 5, the case where the chemical according to the present invention was not added.

Comparative Example 3 This is a case in which the chemical according to the present invention was not added in Example 3.

Comparative Example 4 In Examples 6 and 7, the chemicals according to the present invention were not added.

Comparative Example 5 In Example 8, the chemical according to the present invention was not added. In addition, the amount of the benzotriazole compound in Comparative Example 5 added as an emulsion after the termination of the polymerization is shown.

[0029]

[Table 2]

In Table 2, the benzotriazole compound a) of Comparative Example 3 is 2- (2'-hydroxy-3 ', 5'-di-t-butylphenol) -5-chlorobenzotriazole, and the benzotriazole of Comparative Example 5 is The triazole compound b) is 2-
(3,5-di-t-amyl-2-hydroxyphenyl)
Benzotriazole.

As can be seen from the results in Tables 1 and 2, the chloroprene rubber composition according to the present invention and the adhesive using the same have little discoloration after storage in tin cans and have excellent properties. Recognize.

[0032]

Industrial Applicability As described above, the chloroprene rubber composition according to the present invention and the adhesive using the same have little discoloration after storage in a tin can and are industrially very useful.

─────────────────────────────────────────────────── --Continued from the front page (56) Reference JP-A-7-126442 (JP, A) JP-A-1-121379 (JP, A) JP-A-50-22847 (JP, A) JP-A-7- 70065 (JP, A) JP 59-81348 (JP, A) JP 7-53519 (JP, A) JP 61-118437 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 11/00 C08K 5/3435 C08L 51/04 C09J 111/00 C09J 151/04

Claims (5)

(57) [Claims] 1. A chloroprene rubber composition comprising a chloroprene rubber, a solvent, and a compound having a piperidyl group in the molecule as essential components. 2. The chloroprene rubber composition according to claim 1, wherein the compound having a piperidyl group in the molecule has at least two piperidyl groups in the molecule. 3. The chloroprene rubber composition according to claim 1, wherein the chloroprene rubber is a graft copolymer of chloroprene rubber and methacrylic acid ester and / or acrylic acid ester. 4. An adhesive comprising the chloroprene rubber composition according to any one of claims 1 to 3. 5. The contact according to claim 4, which is contained in a metal container.
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