JPH0288681A - Primer - Google Patents

Abstract

PURPOSE:To obtain a primer for modified acrylic adhesive, having high curing rate, excellent stability, high durability of effects and a little stain to materials to be bonded by dissolving an organometallic chelate compound and an organic compound having reducing properties in an organic solvent. CONSTITUTION:An organometallic chelate compound (e.g. beta-diketone chelates of copper, zinc or aluminum) and an organic compound [preferably beta-diketone. gamma-diketone, hydroxyaldehyde, hydroxycarboxylic acid (ester), hydroxyketone, ketocarboxylic acid, vitamins or amines] having reducing properties are dissolved in an organic solvent (e.g., methanol) to give the aimed primer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention J (Field of Industrial Application) The present invention relates to a primer used for accelerating the curing of a modified acrylic adhesive.

More specifically, the present invention provides a curing accelerating primer composition that has a fast curing speed and excellent stability when bonding using a modified acrylic adhesive, has a long-lasting effect, and has little contamination of the adherend and its surroundings. It is about things.

(Prior art) Modified acrylic adhesives are known as one-component or two-component compositions containing organic peroxides, and -liquid modified acrylic adhesives include anaerobic adhesives and UV-curable adhesives. It is an adhesive called EB curing adhesive, and a two-component modified acrylic adhesive is SGA (Second Generation).

acrylic adhesive). The basic composition of these is a monomer or oligomer having one or more acryloyl or methacryloyl groups in the molecule as the main component, a soluble polymer or elastomer component, an organic peroxide as a radical polymerization initiator, and an amine-aldehyde addition as a redox catalyst. This includes metals, amines, thioureas, metal soaps, and metal organic compounds.

In recent years, modified acrylic adhesives have attracted attention as reactive adhesives in the electronics, electrical industries, and automobile manufacturing industries, and along with cyanoacrylate adhesives, SGA, UV-curable adhesives, and EB are being used as reactive adhesives.
Cured adhesives are beginning to be widely used due to their workability, quick curing, durability, and adhesive properties.

Special Publication No. 534169 as a primer for SGA adhesives
There is a technique described in Publication No. 9. This allows for the use of Schiff bases such as butyraldehyde aniline as the main component of the primer and amines such as N,N dimethylaniline, and metal soaps such as cobalt, iron, copper, and manganese. In addition, Special Publication No. 53-4526,
Japanese Patent Publication No. 53-24103 describes a primer containing an organic peroxide as the main component, and describes a plasticizer paste of benzoyl peroxide and an organic solvent solution containing some resin.

However, these methods have the following practical problems.

One of the problems was that after the primer was applied, the effective time was short and sufficient oven time could not be taken. This was the main cause of reduction and variation in adhesive strength depending on the work. Furthermore, since the main component is liquid, the material that protrudes from the bonded portion remains uncured and tends to contaminate surrounding parts.

Modified acrylic adhesives containing organometallic compounds are disclosed in Japanese Patent Publication No. 48-42467 and Japanese Patent Publication No. 50-366.
There is a technique described in Publication No. 79. This is a resin composition mainly composed of acrylic oligomer and elastomer.
Divided into two liquids, B, liquid A contains metal chelates such as cobalt, vanadium, iron, etc., and liquid B contains organic peroxides such as cumene hydroperoxide and di-t-butyl peroxide. 7. Also, in Japanese Patent Publication No. 54-3766 and Japanese Patent Publication No. 55-1924, a resin composition mainly composed of acrylic monomer and elastomer is divided into two parts A and B, and part A contains an organic compound such as cumene hydroperoxide. It contains peroxide, and liquid B contains thiourea, amines, and metal soap.

However, in systems mainly composed of acrylic oligomers and elastomers, the elastomers that can be used are limited, and because the elastomer contains a metal kit, the elastomer is autooxidized by oxygen in the atmosphere and has poor stability. It was something. It is possible to add an organic compound having reducing properties as defined in the present invention to this composition, but while this can achieve effects such as increasing the adhesion speed, it suffers from poor stability due to auto-oxidation of the elastomer as described above. is accelerated, which is a practical problem.

Systems mainly composed of acrylic monomers and elastomers have odor problems because they contain monomers with low boiling points.
For this purpose, increasing the amount of acrylic oligomer may be considered, but this poses the problem of slowing down the curing speed.

UV curing adhesives and EB curing adhesives are used to fix transparent parts that allow light or electron beams to pass through, but due to their nature, they have the disadvantage that areas that are not exposed to light or electron beams remain uncured. there were. Furthermore, UV curing adhesives having anaerobic curing properties also have a slow curing speed.

(Problems to be Solved by the Invention) Therefore, the present inventors have researched ways to improve these drawbacks, and have found that when bonding using a modified acrylic adhesive containing an organic peroxide as a composition, the curing speed is fast. We have discovered a curing accelerating primer composition that has excellent stability, long-lasting effects, and less contamination of adherends and their surroundings.

[Structure of the Invention] (Means for Solving the Problems) The present invention is a primer for a modified acrylic adhesive, which is prepared by dissolving an organometallic chelate compound and an organic compound having reducibility in an organic solvent.

The organometallic chelate compounds referred to in the present invention include copper, zinc,
β of acetylacetone, dibenzoylmethane, benzoylacetone, etc. of metals such as aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, etc.
- One or more β-ketoester chelates such as diketone chelates, methyl acetoacetate, and ethyl acetoacetate, mixed together, at a concentration of 0.1 to 1 per 100 parts by weight of the organic solvent.
Add 0 parts by weight and dissolve uniformly before use. Organic compounds with reducing properties include β-diketones such as acetylacetone, dibenzoylmethane, and benzoylacetone; 2.5
-hexadione, 1,2-dibenzoylethane, 1-benzoyl 2; γ-diketones such as acetylethane, glycolaldehyde.

Lactaldehyde, glycerylaldehyde, aldol, salicylaldehyde, 3-methoxysalicylaldehyde, vanillin, isovanillin, 2゜4-dihydroxybenzaldehyde, 3.4-dihydroxybenzaldehyde, 3.5-dihydroxybenzaldehyde, 3-hydroxy4- Hydroxyaldehydes such as methoxybenzaldehyde, hydroxynaphthylaldehyde, hydroxyal, barbatol, hydroxycarboxylic acids such as glycolic acid, malic acid, benzylic acid, gallic acid, levulinic acid, barbadic acid, barbatol acid, etc. Esters, benzoin, hydroxyketones represented by 2-hydroxypropiophenone, ketocarboxylic acids represented by pyruvic acid, vitamins and amines represented by ascorbic acid, 1 part per 100 parts of organic solvent.
'J'! Alternatively, 1 to 10 parts by weight of two or more types may be added and used after being uniformly dissolved.

The organic solvent used can uniformly dissolve the metal organic compound and the reducing organic compound, and any solvent can be used as long as the system is stable and the reducing property is not impaired. Examples of organic solvents include alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol, dichloromethane, chloroform, 1.1.1. Halogenated hydrocarbons such as trichloroethane and freon, hydrocarbons such as n-hexane and toluene, ketones such as acetone and MEK,
Esters such as ethyl acetate and butyl acetate, and DMF, DMSO, etc., may be used singly or in combination of two or more to increase solubility.

Polymerizable monomers and oligomers contained in the modified acrylic adhesive referred to in the present invention include acrylic esters and methacrylic esters, specifically methyl (meth)
Acrylate, ethyl (meth)acryle-I, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-ethylhexyl (
meth)acrylate, glycidyl(meth)acrylate, tetrahydrofurfuryl(meth)acrylate, etc.

Examples of polyfunctional (meth)acrylates include mono- or di(meth)acrylates of alkylene glycols or polyalkylene glycols such as ethyl alcohol, propylene glycol, and butylene glycol, and polyfunctional (meth)acrylates such as glycerin, trimethylolpropane, and pentaerythritol. epoxies (such as di(meth)acrylates of bisphenol A alkylene oxide adducts)
Examples include polyester (meth)acrylates such as (meth)acrylates of polyhydric alcohol esters such as meth)acrylates, phthalic acid, trimellitic acid, biromellitic acid, and adipic acid, and polyurethane (meth)acrylates. In addition, soluble polymers contained in the composition include chlorosulfonated polyethylene, NBR,
SDR, chloroprene rubber, natural rubber, 5BS=PM
Examples include MA, phenol resin, etc. Examples of the organic peroxides used include benzoyl peroxide, methyl ethyl ketone peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, and tert-butyl peracetate.

In addition, the modified acrylic adhesive may contain hydroquinone, hydroquinone monomethyl ether, etc. as a stabilizer, and a glass/lath for improving surface hardenability.

(Function) Although the function of the present invention is not clear, the following may be considered. One of them is that metals oxidized by redox reactions are reduced by reducing compounds and recycled effectively. Therefore, it is assumed that the reducing organic compound of the present invention plays a strong role as an auxiliary agent. Another reason is that the reducing organic compound itself acts as a catalyst for the decomposition of organic peroxides. Therefore, the primer composition has a fast curing speed and excellent stability.

(Example) An adhesive composition consisting of the components shown in Table 1 below was prepared.

A primer composition consisting of the components shown in Table 2 below was prepared.

*M M A: Methyl methacrylate 2-HEMA
: 2-hydroxyethyl methacrylate 2-EHMA
: 2-ethylhexyl methacrylate 4G
M: Tetraethylene glycol dimethacrylate ABP
E-4: 2.2bis[4-(acryloxyjethoxy)
Phenyl]propacyTMSMA:Methacryloxybrobyltrimethoxysilane The adhesive composition shown in Table 1 and the primer composition shown in Table 2 were used to measure the fixation time. (Table-3)
Apply adhesive to one side of a mild steel specimen (1.6 x 25 x 100 mm) and apply a primer to the other side. After drying at room temperature for 3 minutes, stack 12.5 m of mild steel specimen (1.6 x 25 x 100 mm) in the shear direction. The adhesion time was defined as the point at which no peeling occurred when a load of 5 kg was applied.

*Based on JIS -6361 alpha-cyano instant adhesive test method After applying the adhesive and primer, adhesive properties were measured after a certain open time.

Apply adhesive to one side of a flat mild steel test piece (1.6 x 25 x room), apply 7 limer to the other side, leave it at room temperature for 1 minute, 60 minutes, and 180 minutes, then paste it together.
After curing for 4 hours, the tensile shear strength was measured.

Table 3 [11 Questions [Effects of the Invention] As described above, the brimer of the present invention is a composition assuming anaerobic properties like Adhesive 1, a composition mainly composed of oligomers like Adhesive 2, A remarkable curing accelerating effect was observed in both systems, such as a composition intended for SGA, such as Adhesive 3, and a UV air curable composition, such as Adhesive 4.

In addition, when the primer was applied and dried and then left to adhere for a long time, it was found that the adhesive strength did not decrease as much as in the case of a composition based on a Schiff base. At that time, the treated surface is in a dry state, so it does not stain the area around the adherend or cause blocking.The 1 primer of the present invention is useful for curing modified acrylic adhesives and has industrial value. It's expensive.

Patent applicant: Toyo Ink Manufacturing Co., Ltd.

Claims (2)

[Claims] (1) A primer for modified acrylic adhesives prepared by dissolving an organometallic chelate compound and a reducing organic compound in an organic solvent. (2) The organic compound having reducing properties is β-diketone, γ-
The primer for a modified acrylic adhesive according to claim 1, which is at least one compound selected from diketones, hydroxyaldehydes, hydroxycarboxylic acids, hydroxycarboxylic esters, hydroxyketones, ketocarboxylic acids, vitamins, and amines.