JP2544787B2 - Primer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (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-promoting primer composition that has a fast curing rate and excellent stability when bonded using a modified acrylic adhesive, has a long-lasting effect, and has little stain on the adherend and its surroundings. It is about things.

(Prior Art) Modified acrylic adhesives are known as one-part or two-part compositions containing an organic peroxide, and one-part modified acrylic adhesives are anaerobic adhesives and UV curing adhesives. Agent, an EB curing adhesive, and a two-component modified acrylic adhesive is typified by SGA (second generation acrylic adhesive). These basic compositions are based on a monomer or oligomer having at least one acryloyl group or methacryloyl group in the molecule as a main component, soluble polymer or elastomer component, organic peroxide as a radical polymerization initiator, amine-aldehyde addition as a redox catalyst. Substances, amines, thioureas, metal soaps, and metal organic compounds.

In recent years, modified acrylic adhesives have been attracting attention as reactive adhesives in the electronics, electric industry, and automobile manufacturing industries, along with cyanoacrylate adhesives, SGA, UV curable adhesives, and EB curable adhesives have good workability, fast curing, It is expected to be widely used because of its durability and adhesiveness.

There is a technology described in Japanese Patent Publication No. 53-41699 as a primer for an SGA adhesive. This uses N, N as a main component of a Schiff base such as butyraldehyde aniline.
Amines such as dimethylaniline and metal soaps such as cobalt, iron, copper and manganese can be used together. In addition, JP-B-53-4526, JP-B-53-24103
In the publication, organic peroxide is the main component of the primer, and a benzoyl peroxide plasticizer paste,
Organic solvent solutions containing some resins are described.

However, these practically have the following problems. One of the problems was that after the primer was applied, its effective time was short and it was not possible to take sufficient open time. This was a main cause of the decrease in adhesive strength and variation depending on the work. In addition, since the main component is liquid, it is liable to leave the material squeezed out from the adhesive portion in an uncured state and cause contamination of peripheral parts.

As a modified acrylic adhesive containing an organometallic compound, there are techniques described in JP-B-48-42467 and JP-B-50-36679. This is a resin composition consisting mainly of acrylic oligomer and elastomer divided into two liquids A and B,
The solution A contains a metal chelate such as cobalt, vanadium, and iron, and the solution B contains an organic peroxide such as cumene hydroperoxide and di-t-butyl peroxide. Further, in Japanese Patent Publication No. 54-3766 and Japanese Patent Publication No. 55-1924, a resin composition mainly composed of an acrylic monomer and an elastomer is divided into two liquids A and B, and liquid A is an organic peroxide such as cumene hydroperoxide. An oxide is arranged, and thiourea, amines, and metal soap are arranged in solution B.

However, the elastomers that can be used are limited in the system containing the acrylic oligomer and the elastomer as a main component, and the liquid A side has poor stability because the elastomer contains a metal chelate and is automatically oxidized by oxygen in the atmosphere. It was An organic compound having a reducing property referred to in the present invention can be added to this composition, but on the other hand, an effect such as an increase in adhesion speed can be obtained, but on the other hand, the poor stability due to the autoxidation of the elastomer as described above. Is accelerated and is a problem for practical use.

The system consisting mainly of acrylic monomers and elastomers has a problem of odor because it contains low boiling point monomers.
Therefore, it is considered that the acrylic oligomer is increased, but there is a problem that the curing speed becomes slower.

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

(Problems to be solved by the invention) Therefore, as a result of researching the improvement of these drawbacks, the present inventors have found that the curing speed is fast when they are bonded using a modified acrylic adhesive containing an organic peroxide as a composition. The present inventors have found a curing-promoting primer composition which is excellent in stability, has a long-lasting effect, and has little stain on the adherend and its surroundings.

[Structure of the Invention] (Means for Solving the Problems) The present invention is a primer for a modified acrylic adhesive obtained by dissolving an organic metal chelate compound and an organic compound having a reducing property in an organic solvent.

The organometallic chelate compound referred to in the present invention is copper, zinc, aluminum, titanium, vanadium, chromium,
One or more kinds of β-diketone chelates such as acetylacetone, dibenzoylmethane and benzoylacetone of metals such as manganese, iron, cobalt and nickel, and β-ketoester chelates such as methyl acetoacetate and ethyl acetoacetate are mixed. Add 0.1 to 10 parts by weight to 100 parts by weight of the organic solvent and dissolve it uniformly before use. Reducing organic compounds include acetylacetone, dibenzoylmethane,
Β-diketones such as benzoylacetone, 2.5-hexadione, 1.2-dibenzoylethane, 1-benzoyl 2
-Γ-diketones such as acetylethane, glycol aldehyde, lactaldehyde, glyceryl aldehyde, aldol, salicyl aldehyde, 3-methoxy salicyl aldehyde, vanillin, isovanillin, 2.4-dihydroxybenzaldehyde, 3.4-dihydroxybenzaldehyde, 3.5-dihydroxybenzaldehyde, 3 -Hydroxy 4-methoxybenzaldehyde, hydroxynaphthyl aldehyde, hydroxal, hydroxy aldehydes such as barbitol, hydroxy carboxylic acids such as glycolic acid, malic acid, benzylic acid, gallic acid, repurinic acid, barbatic acid, barbolic acid and the like. Esters, benzoin, hydroxyketones represented by 2-hydroxypropiophenone, and ketocarboxylic acids represented by pyruvic acid And vitamin typified by ascorbic acid was added to 10 parts by weight of one or more per 100 parts of organic solvent used in uniformly dissolved.

As the organic solvent to be used, any solvent can be used as long as it can uniformly dissolve the metal organic compound and the organic compound having a reducing property and the system is stable and does not impair the reducing property. Examples of the organic solvent include alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol, halogenated hydrocarbons such as dichloromethane, chloroform, 1.1.1. Trichloroethane and freon, hydrocarbons such as n-hexane and toluene, Acetone, ketones such as MEK, esters such as ethyl acetate and butyl acetate, and DMF, DMSO and the like can be used alone or in combination of two or more in order to improve the solubility.

The polymerizable monomers and oligomers contained in the modified acrylic adhesive in the present invention are acrylic acid esters and methacrylic acid esters, and specifically, methyl (meth) acrylate, ethyl (meth) acrylate, 2-
Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate and the like, and ethylene glycol as the polyfunctional (meth) acrylate. , Mono- or di (meth) acrylates of alkylene glycols or polyalkylene glycols such as propylene glycol, butylene glycol, polyfunctional (meth) acrylates such as glycerin, trimethylolpropane, pentaerythritol, and bisphenol A alkylene oxide adducts Epoxy (meth) acrylate such as (meth) acrylate, (meth) actic acid of polyhydric alcohol ester such as phthalic acid, trimellitic acid, pyromellitic acid and adipic acid. Such a polyester (meth) acrylate of the rate, other polyurethane (meth) acrylate and the like to. The soluble polymer contained in the composition is chlorosulfonated polyethylene, NB
R, SBR, chloroprene rubber, natural rubber, SBS, PMMA, phenol resin and the like can be mentioned. Examples of the organic peroxide used include benzoyl peroxide, methyl ethyl ketone peroxide, tertiary butyl hydroperoxide, cumene hydroperoxide, tertiary butyl peracetate and the like.

In addition, the modified acrylic adhesive may contain hydroquinone, hydroquinone monomethyl ether or the like as a stabilizer, and waxes for improving the curability of the surface.

(Operation) Although not clear about the operation of the present invention, the following can be considered. One of them is that the metal oxidized by the redox reaction is reduced by the reducing compound and is effectively recycled. Therefore, it is assumed that the reducing organic compound of the present invention has a high role as an auxiliary agent. Another is that the reducing organic compound itself acts as a catalyst for the decomposition of the organic peroxide. Therefore, the primer composition has a high curing rate and excellent stability.

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

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

The fixing time was measured using the adhesive composition of Table 1 and the primer composition of Table 2. (Table-3) Measurement method ^* Apply adhesive to one side of mild steel test piece (1.6 x 25 x 100 mm), apply primer to the other side and dry for 3 minutes at room temperature, then overlap by 12.5 mm and shear. The time when 5 kg of load was applied in the direction and no separation occurred was defined as the fixing time.

* Based on JIS K-6361 α-Cyano Instant Adhesive Testing Method Also, the adhesive properties were measured when an open time of a certain time was taken after applying the adhesive and the primer.

Measurement method Apply adhesive to one side of mild steel test piece (1.6 × 25 × 100mm), apply primer to the other side, and at room temperature for 1 minute, 60
After being left for 180 minutes, the pieces were bonded and cured for 24 hours, and the tensile shear strength was measured.

[Effects of the Invention] As described above, the primer of the present invention comprises a composition that assumes anaerobicity such as the adhesive 1, a composition mainly composed of an oligomer such as the adhesive 2, and an SGA such as the adhesive 3. A remarkable curing accelerating effect was observed in any of the supposed composition and the UV anaerobic curing composition such as the adhesive 4.

It was also confirmed that when a primer was applied and dried, and then left for a long time to bond, a decrease in adhesive strength as in a composition based on a Schiff base was small. At that time, since the treated surface is in a dry state, it does not stain the periphery of the adherend or cause blocking. From the above, the primer of the present invention is useful for curing a modified acrylic adhesive and has high industrial utility value.

Claims (1)

(57) [Claims] 1. An organometallic chelate compound and at least one reducing agent selected from β-diketone, γ-diketone, hydroxyaldehyde, hydroxycarboxylic acid, hydroxycarboxylic acid ester, hydroxyketone, ketocarboxylic acid, and vitamins. A modified acrylic adhesive primer obtained by dissolving an organic compound in an organic solvent.