JPH01213324A - Curable adhesive composition - Google Patents

Abstract

PURPOSE:To obtain the present composition containing a polymerizable prepolymer, reactive diluent and each specific amounts of spherical inorganic filler and laminar filler, exhibiting high adhesive strength under ambient temperature and having no change of adhesion strength even under soldering temperature. CONSTITUTION:The aimed composition obtained by incorporating 10-50pts.wt. spherical inorganic filler (e.g., spherical melt silica) used as inorganic filler, 50-150pts.wt. laminar filler (e.g., talc) and polymerization initiator (e.g., benzoinisopropyl ether or methylethylketone peroxide) into 100pts.wt. total amount of polymerizable prepolymer (e.g., unsaturated polyester) and reactive diluent [e.g., trimethylolpropane tri(meth)acrylate].

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a curable adhesive composition. This composition is
It hardens under the action of heat and light and is used as an adhesive for chip components.

(Prior art and its problems) Conventionally, in the process of surface mounting chip components such as chip resistors and chip capacitors onto circuit boards using adhesives, several steps of soldering are performed after the components are fixed with adhesives. . During this soldering process, the performance of the adhesive deteriorates due to sudden thermal shock, resulting in the inconvenient problem of parts falling off. For this reason, there is a need for an adhesive that has high adhesive properties and does not change its adhesive strength before and after the soldering process.

(Object of the Invention) The present invention is an adhesive that overcomes the problems of the above-mentioned prior art, and is suitable for bonding chip components to printed circuits.

The present invention aims to provide a curable adhesive composition that can be effectively used as an adhesive for surface mounting on a substrate.

(Structure and effects of the invention) The present invention is as follows.

(1) A curable adhesive composition containing a polymerizable prepolymer, a reactive diluent, a polymerization initiator, and an inorganic filler, wherein the inorganic filler is As spherical inorganic filler 10
-50 parts by weight and 50 to 150 parts by weight of flaky filler, wherein the flaky inorganic filler is flaky talc or/and flaky clay.
The curable adhesive composition described.

The curable adhesive composition of the present invention exhibits high adhesive strength at room temperature, and the adhesive strength hardly changes even when repeatedly exposed to soldering temperatures, thus effectively preventing components from falling off. Can be done.

Examples of the polymerizable prepolymer in the present invention include unsaturated polyester, epoxy (meth)acrylate, urethane (meth)acrylate, oligoester (meth)acrylate, and the like.

The above-mentioned unsaturated polyester is a polyester with molecules ii, ooo to 10,000 having ethylenically unsaturated bonds, and commercially available products include U-Pica 8554 (manufactured by Nippon Ubica) and Nutrak 410S (manufactured by Kao Corporation). ) etc.

The above-mentioned epoxy (meth)acrylate is obtained by esterifying an epoxy resin with a backbone of bisphenol A, phenol, or cresol novolak with (meth)acrylic acid.
Examples include P-1509 and 5P-4010 (manufactured by Showa Kobunshi Co., Ltd.).

The above urethane (meth)acrylates are diols such as aliphatic diols (such as ethylene glycol), ether diols having two hydroxyl groups at the ends of the ether chain, and ester diols having two hydroxyl groups at the ends of the ester chain. and a stoichiometric excess of diisocyanates such as toluene diisocyanate and inphorone diisocyanate, resulting in a urethane compound having an isocyanate group at the end, which is further reacted with hydroxyalkyl (meth)acrylate. can be obtained. Commercially available products include Uvisan 893 (manufactured by Thiokol) and U-6HA (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.).

The above oligoester (meth)acrylate is a polyfunctional (meth)acrylate whose skeleton is an ester compound obtained from an aromatic carboxylic acid, and commercially available products include the trade name Aroninx M-8060, Aroninx M-7100 (Toa (manufactured by Synthetic Kagaku Co., Ltd.), etc.

The reactive diluent in the present invention is used to adjust the viscosity of the curable composition and the properties of the cured product, and includes polyfunctional (meth)acrylates, monofunctional (meth)acrylates, and the like. These may be used alone or in combination depending on the purpose.

The above polyfunctional (meth)acrylates include trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tris(acryloxyethyl)isocyanurate), 1.6 -Hexanethiol di(meth)acrylate, triethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, etc. ,
Further examples include (meth)acrylated bisphenol A to which ethylene oxide has been added or diglycidyl ester di(meth)acrylate of dibasic fatty acid having 4 or more carbon atoms. As a commercially available product, the product name is Viscoat #37.
00, #700 (manufactured by Osaka Organic Co., Ltd.), MANDA (manufactured by Nippon Kayaku Co., Ltd.), Aronix M6100, MANDA M630
0 (manufactured by Toagosei Kagaku Co., Ltd.), Monocizer TD-1600
A (manufactured by Dainippon Ink Co., Ltd.), tJLB-20GEA
(manufactured by Mazai Oil Co., Ltd.), etc.

Examples of the monofunctional (meth)acrylates include hydroxyal (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, phenoxyethyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and the like.

The polymerization initiator in the present invention is the following photopolymerization initiator and/or thermal polymerization initiator.

As photopolymerization initiators, benzoin ether compounds,
Examples include benzophenone compounds, acetophenone compounds, thioxanthone compounds, and specific examples include benzoin isopropyl ether, benzoin isobutyl ether, benzophenone, 2,2-dimethoxy-2-phenylacetophenone, and 1-hydroxycyclohexyl phenyl ketone. , p-isopropyl-α-hydroxyisobutylphenone, α-hydroxyisobutylphenone, 1,1-dichloroacetophenone, 2-chlorothioxanthone, 2-methylthioxanthone, methylbenzoyl formate, and the like. One or more of these can be used.

Moreover, as a thermal polymerization initiator, a usual organic peroxide is used. Specifically, ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide, diacyl peroxides such as acetyl peroxide and benzoyl peroxide, and hydroperoxides such as t-butyl hydroperoxide and cumene hydroperoxide. , dialkyl peroxides such as di-t-butyl peroxide and dicumyl peroxide, alkyl peresters such as t-butyl peracetate and t-butyl perbenzoate, diisopropyl peroxydicarbonate, bis(4-t- butylcyclohexyl)
Peroxycarbonates such as peroxydicarbonate, 1.1-bis(t-butylperoxy)3,3.5
-trimethylcyclohexane, 1. Examples include peroxyketals such as l-bis(t-butylperoxy)cyclohexane. One or more of these can be used.

The inorganic filler in the present invention is a combination of a spherical inorganic filler and a flaky inorganic filler.

Examples of the spherical inorganic filler include spherical fused silica,
Examples include glass beads, granular alumina, silica balloons, synthetic calcium silicate, and the like.

In addition, examples of flaky inorganic fillers include talc,
Examples include calcium silicate, zeolite, kaolin, calcined lebentonite, sericite, and basic magnesium carbonate.

Commercially available products include FB-44 (spherical fused silica) manufactured by Denki Kagaku Co., Ltd., EGB-210 (glass beads) manufactured by Toshiba Varotini, LMR-100 (1 flake talc) manufactured by Fuji Talc, and Ice manufactured by Bergen Pigment. Berg (flake-like clay), etc. are mentioned.

In particular, it is effective to combine a specific amount of spherical fused silica or glass beads as the spherical inorganic filler and talc as the flaky inorganic filler.

In the present invention, the content of the spherical inorganic filler is 1 part by weight per 100 parts by weight of the total amount of the polymerizable prepolymer and the reactive diluent.
The content of the flaky inorganic filler is in the range of 50 to 150 parts by weight. If either or both of the content of the spherical inorganic filler and the content of the flaky inorganic filler is less than the lower limit of the above specified range, the adhesive strength after the soldering process will decrease significantly, and the content will exceed the upper limit. In this case, the initial adhesive strength before the soldering process decreases, and in either case, the object of the present invention cannot be achieved.

These contents can be appropriately adjusted within the above specified range to achieve a viscosity suitable for the purpose of use.

The content (weight) of the polymerizable prepolymer and the reactive diluent can be changed as appropriate, but the polymerizable prepolymer:
The reactive diluent is preferably in the range of (10:90) to (80:20), particularly (20:80) to (70:30).

The content of the polymerization initiator is usually 0.2 to 20 parts by weight based on 100 parts by weight of the total amount of the polymerizable prepolymer and the reactive diluent.
Parts by weight.

The curable composition of the present invention may contain other components as necessary within a range that does not impede the object of the present invention.Other components include a chelating agent, a thermal polymerization inhibitor, a coloring agent, Examples include thixotropic agents and curing accelerators.

Specifically, the chelating agent includes iminodiacetic acid, N-
Methyliminoniacetic acid, nitrilotriacetic acid, ethylenediamine-N, N'-diacetic acid, ethylenediamine-N, N, N
',N'-tetraacetic acid, N-2hydroxyethylethylenediamine N,N',N'-triacetic acid and their sodium salts, N,N.

Examples include N',N'-tetrakis=(2hydroxypropyl)ethylenediamine.

Examples of the thermal polymerization inhibitor include hydroquinone, P-methoxyphenol, benzoquinone, phenothiazine, and cuperone.

Examples of colorants include azo, phthalocyanine, isoindolinone, anthraquinone, carbon black, and the like.

Examples of the thixotropic agent include bentonite and ultrafine anhydrous silica.

As curing accelerators, long-chain organic acid metal salts such as cobalt naphthenate and cobalt octenoate, dimethylaniline,
Amines such as N-phenylmorpholine, quaternary ammonium salts such as triethylbenzylammonium chloride,
Aminophenols such as 2,4.6-)lis(dimethylaminomethyl)phenol are exemplified.

The composition of the present invention is generally produced as follows.

After a polymerizable prepolymer, a reactive diluent, a photopolymerization initiator, a polymerization inhibitor, a chelating agent, etc. are uniformly dissolved in advance, a thixotropic agent, an inorganic filler, a coloring agent, etc. are added and mixed and dispersed.

Then, a thermal polymerization initiator is added and mixed uniformly. The mixture is
It is usually carried out at 60°C or lower using a rotary stirrer or three rolls.

(Examples and Comparative Examples) The measurement methods and meanings of the characteristics listed in the table below are as follows.

[Initial adhesive strength]

Approximately 0.3 to 0.5 mg of the curable composition is applied to the printed circuit board.
Coat the chip part (3.2 mm x 1.
6mII size multilayer ceramic capacitor)
After that, under 20c+n of high pressure mercury lamp with input 80W/CJ.
After irradiating ultraviolet light for about 20 seconds at a distance of
Heat for 10 minutes in a 20°C atmosphere. Thereafter, the shear adhesive strength (A) (kg) per 1 chip at room temperature is measured for the obtained sample.

[Adhesive strength after immersion in solder bath]

The prepared sample is immersed in a 260° C. solder bath for 10 seconds and cooled to room temperature. After performing this operation 6 times, shear adhesive force per l chip at room temperature CB) (kg
) to measure.

[Adhesive strength maintenance rate after immersion in solder bath]

Adhesive strength maintenance rate (%).

Examples 1 to 3 and Comparative Examples 1 to 4 "Parts" on each side are parts by weight.

A mixture was prepared by thoroughly stirring the ingredients according to the following recipe.

100 parts of unsaturated polyester (manufactured by Nippon U-Pica Co., Ltd., U-Pica 8554, molecular weight approximately 2500), 70 parts of bifunctional acrylate (ULB-20GEA, manufactured by Interzai Oil Co., Ltd.), 100 parts of tetrahydrofurfuryl methacrylate, and then 100 parts of the above mixture as shown in the table below. A spherical filler, a flaky filler, and a random-shaped filler were added to the mixture and stirred at 40'C or less to prepare a composition.

When the properties of this composition were investigated, the results shown in the table below were obtained. The results show that the compositions of Examples according to the present invention are superior to those of Comparative Examples.

Claims (2)

[Claims] (1) A curable adhesive composition containing a polymerizable prepolymer, a reactive diluent, a polymerization initiator, and an inorganic filler,
10 to 5 parts of spherical inorganic filler as an inorganic filler per 100 parts by weight of the total amount of polymerizable prepolymer and reactive diluent.
A curable adhesive composition comprising 0 parts by weight and 50 to 150 parts by weight of a flaky filler. (2) The curable adhesive composition according to claim 1, wherein the spherical inorganic filler is spherical, fused silica, or glass beads, and the flaky inorganic filler is flaky talc or/and flaky clay.