JPH0827447A - One-pack type chloroprene-based adhesive - Google Patents

Abstract

PURPOSE:To obtain a one-pack type chloroprene-based adhesive containing choroprene rubber, a specific ketimine type silane, a tackiness-providing resin and an organic solvent as essential components, excellent in storage stability, adhesiveness and heat resistance and useful for industries, etc. CONSTITUTION:This one-pack type chloroprene-based adhesive consists essentially of (A) 100 pts.wt. of a chloroprene rubber, (B) 5-30 pts.wt. [based on 100 pts of the component A] of a ketimine type silane of formula III obtained by reacting an aminoalkoxy silane of formula I [R<1> is a 1-4C monovalent saturated hydrocarbon; R<2> is a 1-10C bivalent hydrocarbon; (n) is 1-3] with a monocarbonylated compound of formula II (R<3> and R<4> are each a 1-10C monovalent hydrocarbon or H) in the presence of a dehydrating agent and/or an organosilicon compound produced by carrying out hydrolytic condensation of an alkoxy group of the ketimine type silane, (C) preferably 10-100 pts.wt. of a tackiness-providing resin such as an alkylphenol resin and (D) an organic solvent such as toluene.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-pack type chloroprene-based adhesive, and more particularly to a one-pack type chloroprene-based adhesive excellent in storage stability and heat resistant adhesive strength.

[0002]

2. Description of the Related Art Conventionally, chloroprene rubber as a main component has been used to dissolve tackifiers such as phenol resin derivatives, vulcanizing agents such as metal oxides, antioxidants, vulcanization accelerators and fillers in organic solvents. Or, there is a dispersed one-component solvent-type chloroprene-based adhesive, which is widely used from industrial to general household use. However, heat resistance, especially at high temperature (80-13
The strength (0 ° C.) and the creep property are weak. Therefore, a two-component type in which an isocyanate curing agent is combined is adopted.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a one-pack type chloroprene-based adhesive exhibiting excellent heat resistance equal to or higher than that of a two-pack type and excellent in storage stability. Therefore, as a result of earnest research, it was found that if a ketimine-type silane is used as a modifier for chloroprene rubber, it has excellent heat resistance and storage stability, and completes the present invention. Came to.

That is, according to the present invention, by introducing a ketimine type silane into a chloroprene-based adhesive, a one-pack chloroprene having extremely excellent heat resistance and storage stability as compared with the conventional one-pack chloroprene adhesive. The purpose is to provide a system adhesive.

[0005]

In order to solve the above problems, in the one-pack type chloroprene adhesive of the present invention,
It contains chloroprene rubber, ketimine type silane, tackifying resin and organic solvent as essential components.

The chloroprene rubber used in the present invention refers to generally commercially available polychloroprene, carboxyl group-containing polychloroprene and the like.

The ketimine type silane preferably used in the present invention is produced by hydrolysis condensation of an organosilicon compound having a ketimine structure represented by the following general formula (A) and / or an alkoxyl group of the organosilicon compound. The organic silicon compound can be mentioned.

[0008]

[Chemical 4]

[Wherein R ¹ is a monovalent saturated hydrocarbon group having 1 to 4 carbon atoms, R ² is a divalent carbon hydrogen group having 1 to 10 carbon atoms, and R ³ and R ⁴ are carbon atoms] A monovalent hydrocarbon group having 1 to 10 atoms or a hydrogen atom (in the case where R ³ and R ⁴ are connected to form a ring, represents a divalent saturated hydrocarbon group having 5 to 10 carbon atoms, It does not become a hydrogen atom at the same time),
n represents 1, 2, 3]

The organosilicon compound represented by the general formula (A) reacts the aminoalkoxysilane represented by the general formula (B) with the monocarbonyl compound represented by the general formula (C) in the presence of a dehydrating agent. Can be obtained.

[0011]

Embedded image

[Wherein R ¹ is a monovalent saturated hydrocarbon group having 1 to 4 carbon atoms, R ² is a divalent hydrocarbon group having 1 to 10 carbon atoms, and n is 1, 2, 3 Represents]

[0013]

[Chemical 6]

[In the formula, R ³ and R ⁴ have 1 to 10 carbon atoms.
10 monovalent carbon-valent hydrogen groups or hydrogen atoms (when R ³ and R ⁴ are connected to form a ring, the number of carbon atoms is 5 to 10).
Represents a divalent saturated hydrocarbon group and does not simultaneously represent a hydrogen atom))

Examples of the aminoalkoxysilane represented by the general formula (B) include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane and the like.

The monocarbonyl compound represented by the above general formula (C) includes acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl cyclohexane,
Examples thereof include diethyl ketone.

As the dehydrating agent, although generally used ones can be used, (anhydrous) sodium sulfate,
Specific examples include (anhydrous) magnesium sulfate, molecular sieves, and dicyclohexylcarbodiimide. Considering the cost in this (anhydrous)
Sodium sulfate is suitable.

When the organosilicon compound represented by the general formula (A) is produced, the molar ratio is monocarbonyl compound (C) / aminoalkoxysilane (B) = 1.0 to 1.
It is necessary to satisfy 0.0. When the molar ratio is 1.0 or less, active amino groups remain, and when added to the organic resin, changes with time such as thickening occur, which is not preferable. On the other hand, if the molar ratio is 10.0 or more, the yield at the time of production becomes too low, resulting in high cost, which is not preferable.
More preferably, a molar ratio in the range of 1.2 to 5.0 gives good results.

The amount of the dehydrating agent may be an amount sufficient to adsorb H ₂ O produced in the reaction, and generally, {aminoalkoxysilane (B) + monocarbonyl compound (C)} total. It is better to add 2% by weight or more of the amount. It is more preferable to use 5% by weight or more.

Further, this reaction needs to be carried out under an inert gas such as nitrogen or argon because the reaction product is hydrolyzed and decomposes in the presence of moisture. Also, if necessary,
Toluene, xylene, benzene, ethylene chloride,
You may use the organic solvent which does not have active hydrogen, such as chloroform, trichloroethylene, hexane, and cyclohexane.

The reaction temperature for carrying out the dehydration reaction may be in the temperature range of -30 ° to 150 ° C. 0 °
It is more preferable to carry out the reaction in the range of -80 ° C. The water adsorption mechanism of the dehydrating agent is a kind of equilibrium state of water adsorption ⇔ water release, and the amount of water release on the high temperature side is slightly larger than that on the low temperature side. Is more preferable because it undergoes further hydrolysis. On the contrary, on the low temperature side, the reaction rate becomes too slow, which is not preferable.

After the completion of the reaction, it is better to remove the dehydrating agent from the system by means such as filtration as soon as possible. This is not preferable because the alkoxyl group is further hydrolyzed as a result of water being released from the dehydrating agent in an equilibrium state.

The amount of the ketimine type silane added to the chloroprene rubber is 1 to 50 parts, preferably 5 to 30 parts, relative to 100 parts of chloroprene rubber (parts by weight, the same hereinafter). If the addition amount of the ketimine type silane is 1 part or less or 50 parts or more, the effect of the present invention cannot be achieved sufficiently.

As the tackifying resin in the present invention, an alkylphenol resin (t-butylphenol resin),
Examples thereof include terpene-modified phenol resin, rosin-modified phenol resin, rosin resin, hydrogenated rosin ester, petroleum-based resin, and coumarone-indene resin. The amount of tackifying resin used is 10 to 1 with respect to 100 parts of chloroprene rubber.
It may be selected within the range of about 00 copies.

Examples of the organic solvent in the present invention include aromatic solvents such as toluene and xylene, aliphatic solvents such as hexane, ester solvents such as ethyl acetate, ketone solvents such as acetone and MEK, and 1,1,1-trichloroethane. And the like, and mixed solvents thereof.

The one-pack type chloroprene adhesive of the present invention is
It is composed of the above polychloroprene, ketimine type silane, tackifying resin and organic solvent, but if necessary, metal oxide (zinc oxide or magnesium oxide, calcium oxide, etc.), dehydrating agent, catalyst (silane reaction catalyst) , An anti-aging agent, a filler, etc. are mixed in appropriate amounts.

The adhesive of the present invention can be applied to metal, wood, leather, woven fabric, plastic materials (ABS, hard vinyl chloride, polyolefin foam, etc.).

[0028]

EXAMPLES Next, examples and comparative examples will be described.

Synthesis Example 1 N ₂ gas introduction tube, thermometer, Dimroth type condenser,
A 1-liter separable flask equipped with a dropping funnel was charged with 300 g (3.0 mol) of methyl isobutyl ketone and 57 g (0.4 mol) of magnesium sulfate, and γ-aminopropyltrimethoxy was added at room temperature under N ₂ gas flow. 268.5 g (1.5 mol) of silane was slowly added dropwise. The aging was continued for 5 hours with slow stirring at room temperature. Immediately thereafter, the salt was filtered off. Low-boiling components were distilled off from the filtrate at 80 ° C. under reduced pressure to obtain 296 g of a pale yellow transparent liquid (ketimine type silane A). This liquid has a viscosity of 59 cSt and a specific gravity of 1.
002 and a refractive index of 1.4590.

Synthesis Example 2 γ-aminopropyltriethoxysilane 3 was used instead of γ-aminopropyltrimethoxysilane in Synthesis Example 1.
When a similar experiment was conducted using 31.5 g (1.5 mol), a pale yellow transparent liquid having a viscosity of 15.2 cSt, a specific gravity of 0.954 and a refractive index of 1.4464 (ketimine type silane B).
309g was obtained.

Examples 1 to 4 Chloroprene rubber having the composition and the number of parts (weight) shown in Table 1 was kneaded with magnesium oxide in a rubber kneading roll, stretched thinly, and chopped with a cutter. On the other hand, the solvent shown in Table 1 was put into a high-speed stirrer, and then the above kneaded rubber was put into it and heated (30 to 50 ° C.) to dissolve. Thereafter, ketimine type silane, terpene phenol resin (YS Polystar T-130, manufactured by Yasuhara Chemical Co., Ltd.), and an antioxidant were added and mixed with stirring to obtain adhesives.

According to JIS. K. According to 6854, cotton cloths were stuck together to obtain an adhesion test piece. After curing this test piece at 20 ° C. and 65% RH for 72 hours, the normal adhesive strength (kg
f / 25 mm) was measured. Also, use this test piece 8
A 300 g load was applied in an atmosphere at 0 ° C., and the peel length after 24 hours was measured (heat-resistant creep).

Further, in order to check the storage stability, the above adhesive was put in a small can (500 g can), the initial viscosity and the viscosity after the accelerated test (left at 50 ° C. for 1 week) were measured, and these test results are shown. The results are shown in Table 1.

Comparative Example 1 As shown in Table 1, a one-pack type chloroprene adhesive without addition of ketimine type silane was prepared by the same procedure as in Examples 1 to 4. The same tests as in Examples 1 to 4 were conducted on this adhesive, and the results are shown in Table 1.

Comparative Example 2 As shown in Table 1, a two-pack type adhesive prepared by combining an ordinary chloropre-rubber and an isocyanate curing agent was prepared, and the same tests as in Examples 1 to 4 were conducted. Shown in 1.

Comparative Example 3 As shown in Table 1, the same tests as in Examples 1 to 4 were conducted on the adhesives modified with aminosilane instead of ketimine type silane, and the results are shown in Table 1.

[0037]

[Table 1]

The symbols in Table 1 are as follows. Showa Denko Dupont KK, Neoprene AF Showa Denko Dupont KK, Neoprene WHV Ketimine silane A (Synthesis example 1) Ketimine silane B (Synthesis example 2) Shin-Etsu Chemical Co., Ltd. KBM903 (γ- Aminopropyltrimethoxysilane) Sumitomo Bayer Ltd., triphenylmethane triisocyanate (isocyanate curing agent)

[0039]

INDUSTRIAL APPLICABILITY The one-pack type chloroprene-based adhesive of the present invention is excellent in storage stability in spite of the one-pack type, and
It has the same adhesive strength and heat resistance as a two-component adhesive using a conventional isocyanate curing agent.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kazuhiko Sato 4-5-9 Higashigotanda, Shinagawa-ku, Tokyo Cemedine Co., Ltd.

Claims (3)

[Claims] 1. A chloroprene rubber, a ketimine type silane,
A one-pack type chloroprene-based adhesive comprising a tackifying resin and an organic solvent as essential components. 2. A ketimine type silane is represented by the following general formula (A):
The adhesive according to claim 1, which is an organosilicon compound having a ketimine structure represented by and / or an organosilicon compound produced by hydrolysis and condensation of an alkoxyl group of the organosilicon compound. Embedded image [Wherein, R ¹ is a monovalent saturated hydrocarbon group having 1 to 4 carbon atoms, R ² is a divalent carbon hydrogen group having 1 to 10 carbon atoms, and R ³ and R ⁴ are 1 carbon atoms. A monovalent hydrocarbon group having a hydrogen atom number of 10 to 10 or a hydrogen atom (in the case where R ³ and R ⁴ are connected to form a ring, represents a divalent saturated hydrocarbon group having 5 to 10 carbon atoms, and at the same time a hydrogen atom). , N is 1,
Represents two or three] 3. The organosilicon compound represented by the general formula (A) is an aminoalkoxysilane represented by the following general formula (B) and a monocarbonyl represented by the following general formula (C) in the presence of a dehydrating agent. The adhesive according to claim 2, which is obtained by reacting with a compound. Embedded image [Wherein R ¹ represents a monovalent saturated hydrocarbon group having 1 to 4 carbon atoms, R ² represents a divalent carbon hydrogen group having 1 to 10 carbon atoms, and n represents 1, 2, 3] [Chemical 3] [Wherein R ³ and R ⁴ are monovalent carbon-valent hydrogen groups having 1 to 10 carbon atoms or hydrogen atoms (when R ³ and R ⁴ are connected to form a ring, they have 5 carbon atoms). Represents a divalent saturated hydrocarbon group of 10 and does not become a hydrogen atom at the same time)]