JPS6354480A - Adhesive composition - Google Patents

Abstract

PURPOSE:To obtain an adhesive which allows the bonding of butyl rubber having little unsaturated bonds to be carried out without heating and has excellent alkali resistance, by using a specified urethane-modified epoxy resin, a specified NBR and a specified silane compd. as components. CONSTITUTION:An adhesive compsn. contains the following urethane-modified epoxy resin, a liquid acrylonitrile/butadiene rubber copolymer (NBR) having amino groups at its terminals and a specified silane derivative. The urethane- modified epoxy resin is obtd. by reacting an epoxy resin having at least two epoxy groups and hydroxyl groups with a compd. having NCO groups at both terminals obtd. by reacting both terminals of polytetramethylene glycol having a mol.wt. of 500-10,000 with a diisocyanate. In the formula, R is a group having epoxy, amino and mercapto groups; X, X' and X'' are each a group composed of C, H and optionally O or an alkoxy group.

Description

[Detailed Description of the Invention] ■ Technical Field The present invention relates to an adhesive composition, and more specifically, it is used to bond rubber materials with very few unsaturated bonds, such as ethylene propylene rubber, to concrete, mortar, etc. The present invention relates to an epoxy resin adhesive composition.

■ Conventional technology Conventionally, it has been difficult to bond rubber materials with very few unsaturated bonds, such as vulcanized butyl rubber and ethylene propylene diene terpolymer rubber (EPDM), at room temperature because they have poor chemical reactivity. Therefore, it was extremely difficult. Therefore, for bonding these materials, a method is used in which an adhesive is used after performing corona discharge, surface oxidation by flame treatment, mechanical surface treatment, or the like. Adhesives in this case include chloroprene-based, urethane-based solvent-based adhesives, and
Examples include epoxy adhesives described in Japanese Patent Publication No. 201869. However, they have drawbacks such as low adhesive strength and poor alkali resistance, which is required when used on concrete or mortar surfaces.

■ Purpose of the Invention The purpose of the present invention is to bond vulcanized rubber, such as butyl rubber or ethylene propylene diene terpolymer rubber (EPDM) with few unsaturated bonds, to concrete, mortar, etc. without heating. , especially in the civil engineering and architectural fields, such as concrete and mortar that need to be alkali-resistant, such as pasting roof waterproof sheets, etc.
The object of the present invention is to provide an adhesive composition that can be used in a wide range of fields such as the automobile industry and the electrical industry.

■Specific structure of the invention The first aspect of the present invention is to react a polytetramethylene glycol having a molecular weight of 500 to 10,000 with a diisocyanate at both ends, and a compound having -NCO groups at both ends. A urethane-modified epoxy resin obtained by reacting the above epoxy resins having an epoxy group and a hydroxyl group, and a liquid acrylonitrile having an amino group at the end.
butadiene rubber copolymer, and (where R represents a group having an epoxy group, an amino group or a mercapto group, and x, x', and or an alkoxy group).

A second aspect of the present invention is a compound having -NCO groups at both ends obtained by reacting a diisocyanate at both ends of polytetramethylene glycol having a molecular weight of 500 to 500, and two or more epoxy groups and a hydroxyl group. A urethane-modified epoxy resin obtained by reacting an epoxy resin with a liquid acrylonitrile having an amino group at the end
butadiene rubber copolymer, and (where R represents a group having an epoxy group, an amino group or a mercapto group, and x, x', and or an alkoxy group) and an acrylonitrile-butadiene copolymer rubber.

A third aspect of the present invention is a compound having -NCO groups at both ends obtained by reacting a diisocyanate at both ends of polytetramethylene glycol having a molecular weight of 500 to 10,000, and two or more epoxy groups and a hydroxyl group. A liquid acrylonitrile-butadiene rubber copolymer having an amino group at the terminal, and (where R is a group having an epoxy group, an amino group or a mercapto group) x, x', and X'' each represent a group composed of carbon, hydrogen, and optionally oxygen, or an alkoxy group) and epoxidized natural rubber. provide something.

Hereinafter, the configuration of the present invention will be explained in detail.

In the present invention, polytetramethylene glycol (PT
MG) has hydroxyl groups at both ends, and has a molecular size of 1500
-10,000, and usually has a molecular weight of 650-400
0 is commercially available and is preferably used.

The reason why the molecular weight is set to such a value is that when the molecular weight is less than 500, the cured product becomes hard and the peel strength becomes low.
Moreover, when it exceeds 10,000, the viscosity of PTMG increases,
This is because it becomes difficult to synthesize a urethane-modified epoxy resin.

In addition, as the diisocyanate to be reacted with the hydroxyl groups at both ends, diisocyanates such as tolylene diisocyanate (TDI), methylene diphenyl diisocyanate (MDI), hydrogenated MDI, isophorone diisocyanate (IPDI), and xylylene diisocyanate (XDI) are used. You can use any of them if you are a nat.

When reacting with PTMG, these diisocyanates react with one -NCO group of the diisocyanate with one hydroxyl group of PTMG, leaving one -NCO group and forming -NCO groups at both ends. It is acceptable even if unreacted diisocyanate remains as a result of adding an excess of diisocyanate.

The intermediate thus produced is then reacted with an epoxy resin containing two or more epoxy groups and a hydroxyl group.

This epoxy resin has a so-called bisphenol A type or F type epoxy resin obtained by reacting bisphenol A, bisphenol F, etc. with epichlorohydrin, or a hydroxyl group functional number obtained by reacting trimethylolpropane with epichlorohydrin. Even if the number is less than 1 (for example, 0.8 is commercially available), it can be used.

Therefore, as long as there are two or more epoxy groups and a hydroxyl group, it is not limited to those listed in L.

These hydroxyl groups react with the above-mentioned intermediate containing an incyanato group at the end, and as a result, a urethane-modified epoxy resin containing an epoxy group at the end can be obtained.

In this reaction, if the number of hydroxyl groups in the epoxy resin having two or more epoxy groups and hydroxyl groups is one per molecule, there is no problem when one hydroxyl group is reacted with one isocyanate group. However, there are many cases where two or more epoxy resins are included, and in that case, it is better to add an excess of epoxy resin because it will gel during the reaction.

In the present invention, a liquid acrylonitrile-butadiene rubber copolymer (NBR) having an amino group at the end is
For example, acrylonitrile-butadiene copolymer 1lyc
ar ATBN 1300 X 16 (manufactured by BF Gutdrich), etc., and is used as a curing agent component of epoxy resin.

In the present invention, liquid NBR having an amino group at the terminal is an essential component, but other curing agents such as polyamide amine and modified heterocyclic diamine are also used.

It may be used in combination with epoxy resin curing agents such as aliphatic amines, aromatic amines, and modified products thereof, or curing accelerators such as tertiary amines and imidazole. For example, when the above-mentioned Hycar ATBN is used alone, curing is slow, and it is preferable to use it in combination with other curing agents or curing accelerators.

The silane coupling agent which is an essential component in the present invention has the formula %Formula% In the above formula, R represents a group having an epoxy group, an amino group, or a mercapto group, and Xl, X' and X# each represent an alkoxy Represents a group or a group composed of carbon, hydrogen and, in some cases, oxygen,
Specifically, the compounds are exemplified below.

This silane coupling agent improves adhesive strength to concrete and mortar, and in turn improves alkali resistance.

Examples of the silane coupling agent used in the present invention include γ-glycidoxyprobyltrimethoxysilane,
Di(γ-glycidoxyprobyl)dimethoxysilane, β
-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-aminopropyltriethoxysilane,
Examples include N-β-aminoethyl-γ-aminopropyldimethoxymethylsilane, γ-(N-phenylamino)propyltrimethoxysilane, mercaptopropyltriethoxysilane, and mercaptopropyltrimethoxysilane.

There is no particular limit to the amount of these additives, but from the economical point of view, 0.05 to 10 parts by weight based on the amount of the urethane-modified epoxy resin and curing agent is generally appropriate.

Furthermore, if necessary, the adhesive of the present invention may contain silica, talc,
Inorganic fillers such as calcium carbonate, clay, calcium silicate, etc. can be suitably added.

Additionally, additives such as anti-sagging agents, dispersants, antifoaming agents, leveling agents, heat-resistant anti-aging agents, plasticizers such as DOP and DOA, MEK, toluene, xylene, and other solvents may be added. preferred from the viewpoint of sex.

Further, in order to improve initial adhesion, it is particularly preferable to add solid NBR (acrylonitrile-butadiene copolymer rubber) or epoxidized natural rubber. From this point of view, it is also preferable to add liquid polymers, tackifiers, etc. Moreover, vinyl chloride, vinyl chloride-vinyl acetate copolymer, thermoplastic urethane, etc. can also be added to increase adhesive strength.

In the present invention, a two-component adhesive containing a urethane-modified epoxy resin or a curing agent on each side can be used as a two-component room temperature curing adhesive.

(2) Examples The present invention will be specifically explained below with reference to Examples and Comparative Examples.

Examples were prepared using the ingredients shown in Table 1 in a predetermined number of parts. In addition, the comparative example is JP-A-58-2018
The compound described in No. 69 was used in the formulation examples shown in Table 2.

As the adherend to be adhered, an EPDM rubber sheet, which is generally commercially available as a rooftop waterproofing sheet, was used, and as the adherend to these sheets, a mortar plate was used.

EPDM rubber sheet has a width of 25++us and a length of 180mm.
A mortar plate with a width of 120 mm is used.
A test piece with a length of 180 m5 and a thickness of 10 a+m was used.

The adhesive is obtained by mixing liquids A and B. The material is evenly applied to the surface of each test piece to a weight of 500 g/m2, dried for 1 hour, and then bonded.
A 180° peel test was conducted at a tensile rate of 0.00 mm/sin to evaluate the normal adhesive strength.

Furthermore, alkali resistance was determined by immersing the two days after bonding separately in a calcium hydroxide saturated aqueous solution (40°C) for two days, washing with water, and immediately conducting a 180° peel test at a tensile speed of 200 arm/win. evaluated. In addition, the adhesive strength immediately after lamination is taken as the initial adhesive strength of 200
It was measured by performing a 90° peel test at a tensile rate of mad/win.

Table 1 shows the results of Examples and Comparative Examples.

From the results in Table 1, it can be seen that the products of the present invention not only provide sufficient adhesive strength but also have excellent alkali resistance.

Table 1 (Part 1) Table 1 (Part 2) Urethane modified epoxy resin (epoxy equivalent: 298) Umbrella 2 A-187 CH2-CH-CH20CH2CH2CH2S 1 (
OCH3) 3”:Polybd R-45EPI (
(manufactured by Idemitsu Petrochemical Co., Ltd., epoxy equivalent: 200, viscosity: 360 voids/45°C, colorless transparent liquid), ″: Sumie Boxy ELA-128 (manufactured by Sumie Chemical Co., Ltd., epoxy equivalent: 190)
, ”: EXA-140 (manufactured by Dainippon Ink Co., Ltd., epoxy J1470), 4): Fucohol resin FR-
L (manufactured by Fuji Kosan Co., Ltd.), ′)2 dicanol L (manufactured by Mitsubishi Gas Chemical Co., Ltd.), 6): Acrylonitrile butadiene copolymer, 1lycar＾TBN■ (manufactured by BF Gutdrich), amine equivalent 1800, t ＞ : 2,
4J-trisdimethylaminophenol (DMP-30
), 'l aminoadduct of dimethylaminoprobylamine and trimethylolpropane trimethacrylate.

■ Effects of the Invention The adhesive composition of the present invention can bond vulcanized rubber such as butyl rubber or EPDM, which has few unsaturated bonds, to concrete, mortar, etc. without heating, and can obtain sufficient adhesion. It also has excellent alkali resistance.

Furthermore, the adhesive compositions of the second and third aspects of the present invention have improved initial adhesive strength.

For this reason, it is particularly effective in the civil engineering and construction field, such as as a bonding adhesive for rooftop waterproof sheets, and can be used in a wide range of other fields, such as the mountain vehicle industry and the electrical industry.

Claims (3)

[Claims] (1) A compound having -NCO groups at both ends obtained by reacting both ends of polytetramethylene glycol with a molecular weight of 500 to 10,000 with a diisocyanate is reacted with an epoxy resin having two or more epoxy groups and hydroxyl groups. urethane-modified epoxy resin obtained by and X, X', and X'' each represent a group composed of carbon, hydrogen, and in some cases oxygen, or an alkoxy group). . (2) A compound having -NCO groups at both ends obtained by reacting both ends of polytetramethylene glycol with a molecular weight of 500 to 10,000 with a diisocyanate is reacted with an epoxy resin having two or more epoxy groups and hydroxyl groups. urethane-modified epoxy resin obtained by (where X, X', and x'' each represent a group composed of carbon, hydrogen, and in some cases oxygen, or an alkoxy group) and an acrylonitrile-butadiene copolymer rubber. An adhesive composition characterized by: (3) A compound having -NCO groups at both ends obtained by reacting both ends of polytetramethylene glycol with a molecular weight of 500 to 10,000 with a diisocyanate is reacted with an epoxy resin having two or more epoxy groups and hydroxyl groups. urethane-modified epoxy resin obtained by (where X, X', and X'' each represent a group composed of carbon, hydrogen, and in some cases oxygen, or an alkoxy group) and epoxidized natural rubber. Adhesive composition.