JPH03265676A - Primer for alpha-cyanoacrylate adhesive and method of bonding by using it - Google Patents

Abstract

PURPOSE:To obtain the title primer which can remarkably improve the impact resistance, peeling resistance, and water resistance when applied to adherends by using a specified polymer and an organic solvent as the constituents. CONSTITUTION:The title primer contains a polymer which has at least one terminal crosslinkable alkoxysilyl group and whose principal chain essentially comprises a polyether (e.g. MS Polymer 20A, a product of Kanegafuchi Chemical Industry: polypropylene oxide having terminal methyldimethoxysilyl groups) and an organic solvent (e.g. an aromatic hydrocarbon, an alcohol, a ketone or an ether).

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a primer for α-cyanoacrylate adhesives.

More specifically, the present invention relates to a primer for improving impact resistance and water resistance, particularly adhesion to chrome-plated surfaces, which are disadvantages of α-cyanoacrylate adhesives.

<Prior art> α-Cyanoacrylate adhesives are widely used in various industrial fields due to their excellent instant adhesive properties. It has the disadvantage that the thermal shock strength between adherends is low.

Conventionally, in order to improve this drawback, for example, elastomers such as acrylonitrile, butadiene, styrene, and ethylene/vinyl acetate were added (Japanese Patent Application Laid-Open No. 53-306).
43, JP-A-59-145271, U.S. Pat. No. 4,440,910), adding a plasticizer such as dimethyl succinate (U.S. Pat. No. 2,784,12),
7 specification), adding a thermoplastic polymer formed on a rubbery polymer and a sustaining agent (Japanese Patent Publication No. 11879/1987), or adding a carboxylic acid or an acid anhydride (Japanese Patent Publication No. 37262/1982). (Japanese Patent Publication No. 53-5726, Japanese Patent Publication No. 56-54029) have been proposed. Also known is a method of applying an organic silane compound as a primer to the surface to be bonded to improve the impact resistance and water resistance of the bonded area (Japanese Unexamined Patent Application Publication No. 76344/1989,
JP-A-57-110434).

<Problems to be Solved by the Invention> However, the addition of these various additives adversely affects the stability of highly reactive α-cyanoacrylate adhesives and shortens their shelf life. Also, JP-A-52-7
In order to solve these problems, Publication No. 6344 proposes the use of organic silane compounds as primers, but although improvements in impact resistance and water resistance are recognized, they are particularly difficult to use on chrome-plated surfaces, etc. Adhesion of difficult-to-adhesive materials was not fully satisfactory.

The present inventors have conducted extensive research into a primer that can provide sufficient impact resistance and water resistance even on chrome plating surfaces, which are conventionally known as chick bonding materials, in the case of adhesion using α-cyanoacrylate adhesives. This completes the present invention.

Means for Solving the Problems> That is, the present invention is characterized by containing a polymer having at least one crosslinkable alkoxysilyl group at the terminal and whose main chain is essentially a polyether, and an Il-containing solvent. This is a primer for α-cyanoacrylate adhesive.

The α-cyanoacrylate adhesive used in the present invention includes methyl-α-cyanoacrylate, ethyl-α
-cyanoacrylate, n-propyl-α-cyanoacrylate, isopropyl-α-cyanoacrylate, n
-Butyl-α-cyanoacrylate, Isobutyl-α-
Examples include cyanoacrylate, 2-methoxyethyl-α-cyanoacrylate, and the like.

The polymer used in the present invention that has a crosslinkable alkoxysilyl group at the end and whose main chain is essentially a polyether is:
The main chain contains chemically bonded repeating units represented by the formula -R'-0- (wherein R' represents a divalent alkylene group having 1 to 4 carbon atoms), and the terminal functional A polymer whose group is an alkoxysilyl group.

The chemically bonded repeating unit represented by the formula -R'-0- includes, for example, -CHtO--CHtCHtO-CH
2ctHs CH-CHtO--CHCHzO--CHtCIIzC
Specific examples include HzCHzO-. Although these may be used alone or in the form of a mixture, polyoxypropylene is particularly preferably used.

Specific examples of alkoxysilyl groups include CH3 Si (OCH3)! , -3i (OCHs)1, -5
i (OCHs)zO5i (CH3)3 , OCH
, OCR.

5i (QC□Hs)s, -540-5i (CHs)
Among them, methyldimethoxysilyl group is particularly preferably used.

Such polymers can be produced, for example, by the method described in JP-A-54-6096 or JP-A-61-159419.

In the polymer, the crosslinkable alkoxysilyl group is
It has at least one alkoxysilyl group at the end of the main chain polyether, and those having the alkoxysilyl group at both ends of the main chain polyether are preferably used, but substituents other than the alkoxysilyl group at the other end, For example, 1st grade a
Those having a group such as 0 are also preferably used.

Specific examples of such polymers include MS Polymer 20
Examples include those commercially available as A, MS Polymer 300, Cyryl 5AO1, Cyryl 5B25, and Cylyl 5830 (all manufactured by Kanekabuchi Kagaku Co., Ltd.).

In addition to the above-mentioned polymers, compounds conventionally known as primers, such as amino group-substituted silane compounds, vinyltrichlorosilane, etc., can also be used in combination with the primer in the present invention.

Examples of amino group-substituted silane compounds that can be particularly preferably used in combination in the present invention include HtomiNCHxCHiCHzSi (OCRs)s, HJ
CHzCHJHCHzCHzCHzSi(OCRs)z
, H3 HJCHzCHJl(CHzCHtCHzSi(OCH
3) z - (CzHsO)*5iCHzC)ltc)
lJHcHzcHzNHcI(zcHzcHtsi(0
Amino device alkoxysilane such as CzHs)s, and the above amino group-substituted alkoxysilane and muff CHzOCH
t-Hs CHz=C-C-0-CHzCHzCHzSi (OC
Rs) s1 CB.

CHz=C-C-0-CHtCHzCHzSi (OC
Examples include reactants with methacryloxysilane compounds such as HzCHzOCHs).

The reaction between an amino group-substituted alkoxysilane and an epoxysilane compound or an acryloylsilane compound is carried out by mixing 0.2 to 5 moles of the silane compound to 1 mole of the 75-substituted alkoxysilane at a temperature ranging from room temperature to 180°C. It can be easily obtained by stirring for 1 to 8 hours.

The above amino group-substituted alkoxysilane or amine group-substituted alkoxysilane derivative compound is used in an amount of 0.01 to 20 parts by weight per 100 parts by weight of the polyether polymer having a crosslinkable alkoxysilyl group at its terminal.

Cramer for α-cyanoacrylate adhesive of the present invention,
The Il-containing solvent used here to dissolve the polymer, etc. in an organic solvent may be any solvent that is compatible with the polymer, etc., but specific examples include benzene, toluene, xylene, etc. Aromatic hydrocarbons, methanol, ethanol,
Examples include alcohols such as propatool, ketones such as acetone and methyl ethyl ketone, and ethers such as tetrahydrofuran and dioxane.

The concentration of the polymer etc. in the organic solvent is usually 0.1 to 20
% by weight, preferably 0.5-10% by weight. When the degree of polypropylene oxide is less than 0.1% by weight, the intended purpose is difficult to achieve because the concentration is low, and when the concentration is more than 20% by weight, excessive polypropylene oxide is present on the surface to be adhered. May reduce adhesive strength.

The primer of the present invention is applied to one or both surfaces of the materials to be adhered by a method such as brushing or spraying in a sprayer. If it is a surface, it is more effective to apply it to that surface.

There are various materials that can be bonded using the primer of the present invention, and inorganic materials include steel, chrome-plated steel, aluminum, copper, zinc, glass, and ceramics, and organic materials include is natural rubber, N
Rubbers such as BR, neoprene, EPT, EPDM, polyvinyl chloride, polymethacrylate, polystyrene, AB
S.

Plastics such as phenol resin and melamine resin,
Examples include woods such as cypress, cedar, lauan, and beech.

The combination of materials to be joined that exhibits particularly excellent effects according to the present invention is a combination of inorganic materials or an inorganic material and an organic material, and specifically, II/steel, chrome-plated copper, etc. /Chrome plated steel, Chrome plated fi/E
PDM, glass/natural rubber, glass/ABS, etc.

<Effects of the Invention> When the primer of the present invention is applied to the surface of a material to be bonded and bonded with an α-cyanoacrylate adhesive, the impact resistance, peel resistance, and water resistance of 1IIL/steel are significantly improved. In particular, it can bond strongly even to chrome plating surfaces, which have traditionally been considered difficult to adhere to, and can significantly improve impact resistance, peel resistance, and water resistance.

<Example> Hereinafter, the present invention will be explained in more detail with reference to Examples.

Examples 1 to 5, Comparative Examples 1 to 5 Table 1 shows the results obtained by the following adhesion test method on the adherend materials listed in Table 1 using a primer having the primer composition listed in Table 1. .

The following polymers were used in the examples.

(Example 1) MS Polymer 2OA (manufactured by Kanebuchi Chemical Co., Ltd., polypropylene oxide having methyldimethoxysilyl groups at both ends, number average molecular weight 7500, viscosity (23 ° C) 140 po
(Example 2) MS Polymer #300 (manufactured by Kanekabuchi Chemical Co., Ltd., polypropylene oxide having methyldimethoxysilyl groups at both ends, number average molecular weight 8500, viscosity (23"C) 220
Poise) (Example 3) Cylyl 5^01 (manufactured by Kanebuchi Chemical Industry Co., Ltd., polypropylene oxide having methyldimethoxysilyl groups at both ends,
Number average molecular weight 8500, viscosity (23°C) 150po
ise) (Example 4) Cylyl 5B25 (manufactured by Kanebuchi Kagaku Kogyo Co., Ltd., polypropylene oxide having a methyldimethoxysilyl group at one end and an amino group at the other end, number average molecular weight 8000, viscosity (
23°C) 220poise) (Example 5) Cylyl 5B30 (manufactured by Kanebuchi Chemical Co., Ltd., polypropylene oxide having a methyldimethoxysilyl group at one end and an amino group at the other end, number average molecule 1i5000, viscosity (23°C) 135 Poise) Furthermore, as the α-cyanoacrylate adhesive used in the examples, Cyanobond RP (ethyl α-cyanoacrylate manufactured by Idashi Kagaku Kogyo Co., Ltd.) was used.

The adhesion test was conducted in accordance with JIS K6861 as follows.

1) Brush the primer shown in Table 1 on each adhesive of Centime mild steel plates (25X 100 The time required to withstand a tensile shear load of 5 kg was measured.

2) Adhesion was performed in the same manner as the measurement of tensile shear strength cent time, and after 24 hours, the load rate was 50 k/si using a Shimadzu autograph tester.
Measured at n.

The test piece was made of rope/steel and chrome-plated steel plate (25X 1
00 x 1.6 mm) and measured in the same manner as above.

3) Peel strength chrome plated steel plate (25 x 100 x 1.6 mm)
Using EPDM (25x 100x1.6mm), apply primer to the chrome-plated steel plate with a brush, and apply E
Cyanobond RP was applied to the PDM piece, and 10 CI+ was bonded to a width of 25 m, and a 90 degree peel test was performed after 24 hours.

4) Apply the primer shown in Table 1 to the adhesion surface of each impact strength mild steel plate (25 x 100 x 1.6+m) with a brush, dry, adhere, and leave for 24 hours before applying the adhesive! The strength was measured.

5) Water resistance A test piece of mild steel plates bonded together in the same manner as the set time measurement was left for 24 hours, then immersed in 40°C warm water for 7 days, and then the tensile shear strength was measured, and the value when not immersed in water. The strength retention rate was calculated.

Claims (1)

[Scope of Claims] (1) α-cyano characterized by containing a polymer having at least one crosslinkable alkoxysilyl group at the terminal and whose main chain is essentially a polyether, and an organic solvent. Primer for acrylate adhesive (2) The primer for α-cyanoacrylate adhesive according to claim 1, wherein the crosslinkable alkoxysilyl group is a methyldimethoxysilyl group. (3) The primer for α-cyanoacrylate adhesive according to claim (1) or (2), wherein the polyether is polypropylene oxide. (4) An amino group-substituted silane compound is used in combination with a polymer having at least one crosslinkable alkoxysilyl group and whose main chain is essentially a polyether. Primer for α-cyanoacrylate adhesive according to any one of (3) (5) The concentration of the polymer and/or amino group-substituted silane compound in the organic solvent is 0.
The primer for an α-cyanoacrylate adhesive according to any one of claims (1) to (4), which contains 1 to 20% by weight. (6) A primer containing a polymer having at least one crosslinkable alkoxysilyl group and whose main chain is essentially polyether and an organic solvent is applied to the adhesive, and then α-cyanoacrylate adhesive An adhesion method characterized by adhesion using an agent.