JPH032465B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an adhesive composition containing unsaturated polyester and acrylate as main components. More specifically, the present invention relates to an adhesive composition suitable for uses such as fixing chip parts, which cures in a short time by both light and heat. (Prior Art and its Problems) In recent years, as electronic devices have become smaller and lighter, the demand for small electronic components without lead wires, that is, chip components, has rapidly increased. Along with this, the demand for adhesives for fixing chip components to wiring boards is increasing year by year. Conventionally, thermosetting adhesives are known as adhesives for fixing chip parts. For example, Japanese Patent Publication No. 56-11238 discloses a method of fixing chip components onto a wiring board using an epoxy resin or phenol resin adhesive. However, since the thermosetting adhesives mentioned above usually require curing at high temperatures for a long time, using thermosetting adhesives to fix chip parts makes it difficult to automate the process of mounting chip parts. Moreover, it has the disadvantage that the board, chip parts, discrete parts mounted on the back of the board, etc. are adversely affected by heat. Furthermore, photocurable adhesives that are cured by irradiation with ultraviolet light (light) are also known. Photocurable adhesives are made of polymerizable monomers or prepolymers, photopolymerization initiators, etc., and cure in a short time when exposed to light, eliminating the drawbacks of thermosetting adhesives mentioned above. However, it is often impractical to use these adhesives to secure chip components because shadow areas that are not exposed to light do not harden. Recently, adhesives that cure quickly under the effects of both light and heat have come to be used to fix chip parts. As these adhesives, adhesives are known that have a polyacrylate prepolymer as a main component and contain a photopolymerization initiator and a thermal polymerization initiator. For example, JP-A-57-16083 discloses an adhesive consisting of a polyacrylate prepolymer such as urethane acrylate, epoxy acrylate, or acrylic-modified polybutadiene, and a photo- and thermal polymerization initiator.
Further, JP-A-59-223775 discloses an adhesive comprising an epoxy acrylate prepolymer, a reactive diluent (aliphatic polyester diacrylate), a photopolymerization initiator, a thermal polymerization initiator, and the like. These adhesives cure in a short time by the action of both light and heat, so they overcome the drawbacks of the thermosetting adhesives mentioned above, but they often do not have sufficient adhesion reliability. In other words, the above-mentioned adhesives containing polyacrylate prepolymers as the main component usually have a brittle cured product, and when chip parts are bonded to a substrate using such adhesives, external stress may cause the adhesive to adhere in the post-bonding process. Chip parts may fall off the board. Furthermore, in recent years, the variety of chip parts has increased, and their shapes and materials have become more diverse.As a result, it may be virtually difficult to bond them with adhesives whose main component is the above-mentioned polyacrylate prepolymer. . (Means for Solving the Problems) In view of these points, the inventors of the present invention have made extensive studies and found that by using a combination of specific components described below, the effect of light and heat can be reduced in a shorter time. hardens,
The inventors have discovered that an adhesive composition with excellent adhesion to chip parts of various materials and shapes can be obtained, leading to the present invention. That is, the present invention comprises (A) an unsaturated polyester resin, (B) a tetrahydrofuran ring-containing monomer represented by the following general formula; [However, in the formula, n is an integer of 0 to 4, and R ₁ and R ₂ represent hydrogen or a methyl group. ] (C) hydroxyalkyl acrylate and/or hydroxyalkyl methacrylate, (D) photopolymerization initiator, (E) thermal polymerization initiator. The present invention relates to an adhesive composition containing the above (A), (B), (C), (D) and (E) as essential components. (A) The unsaturated polyester resin used in the present invention is an unsaturated dibasic acid such as maleic acid or fumaric acid, and if necessary, a saturated dibasic acid such as adipic acid or phthalic acid, and ethylene glycol, propylene glycol, or It is obtained by esterifying a polyhydric alcohol such as phenol A in the presence of a catalyst. Commercially available unsaturated polyester resins are usually diluted with reactive diluents such as styrene monomers, but in the case of the present invention, it is preferable to use resins that do not contain diluents such as styrene monomers from the viewpoint of curing speed, odor, etc. The tetrahydrofuran ring-containing monomer (B) used in the present invention is an acrylate and/or methacrylate (hereinafter often referred to collectively as "(meth)acrylate") represented by the above general formula, and typical examples include Examples include, but are not limited to, tetrahydrofurfuryl (meth)acrylate, tetrahydrofurfuryloxyethyl (meth)acrylate, tetrahydrofurfuryloxypropyl (meth)acrylate, and the like. Typical (C) hydroxyalkyl (meth)acrylates used in the present invention include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate. These include, but are not limited to. The amount of each component (A), (B) and (C) used in the adhesive composition of the present invention is the amount of components (B) and (C) used per 100 parts by weight of component (A). The total amount is preferably 20 to 200 parts by weight, and the ratio of component (B) to component (C) is preferably in the range of 1:9 to 9:1 on a weight basis. If the total amount of components (B) and (C) used is less than 20 parts by weight relative to 100 parts by weight of component (A), the adhesiveness to chip parts may decrease or the viscosity of the composition may become too high. Problems such as poor adhesive application workability may occur, and conversely, if the amount exceeds 200 parts by weight, the strength of the resin may decrease, leading to a decrease in adhesive strength. Furthermore, if the ratio of the amounts used of component (B) and component (C) is outside the above range, there is a risk that the adhesion to chip parts may be reduced. In the case of the present invention, for a total of 100 parts by weight of the above-mentioned components (A), (B), and (C), an amount not exceeding 150 parts by weight of other radically polymerizable prepolymers or reactants A diluent can be used. For example, prepolymers include various urethane (meth)allylates, epoxy (meth)allylates, (meth)acrylate-modified liquid polybutadiene, and reactive diluents include (poly)ethylene glycol difluoride. (meth)acrylate, (poly)propylene glycol di(meth)acrylate, trimethylolpropane tri(meth)allylate, pentaerythritol tetra(meth)allylate, methyl(meth)acrylate, ethyl(meth)acrylate, butyl(meth)allylate, ) Acrylate, cyclohexyl (meth)
Acrylate, glycidyl (meth)acrylate, butoxyethyl (meth)acrylate, 1,
6-hexanediol di(meth)acrylate,
Examples include (meth)acrylates such as 1,4-butanediol di(meth)acrylate, styrene, and divinylbenzene. The photopolymerization initiator (D) used in the present invention includes, but is not limited to, benzyl and its derivatives,
Benzophenone and its derivatives, anthraquinone and its derivatives, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, acetophenone and its derivatives, 2-
Examples include diethylaminoethylbenzoate, p-diethylaminoethylbenzoate, diphenyl disulfide, thioxanthone and derivatives thereof, and these may be used alone or in combination of two or more. The usage amount of these photoinitiators is as follows:
The amount of the above (A), (B), (C) and other polymerizable prepolymers and reactive diluents used is preferably 0.01 to 10 parts by weight based on the total of 100 parts by weight, and if it is less than 0.01 part by weight. has a slow curing speed, and if it exceeds 10 parts by weight, the strength of the cured product may decrease. Thermal polymerization initiators used in the present invention include benzoyl peroxide, tert-butyl peroxyallyl carbonate, methyl ethyl ketone peroxide, cyclohexanone peroxide, 1,1-bis(tert-butyl peroxy) 3,3,5- trimethylcyclohexane,
1,1-bis(tert-butylperoxy)
Cyclohexane, tert-butyl hydroperoxide, cumene hydroperoxide,
Ditertiary butyl peroxide, Tertiary butyl cumyl peroxide, Tertiary butyl peroxy 3,5,5-trimethylhexanoate, Tertiary butyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoyl) Typical examples include peroxy)hexane, particular organic peroxides, and azobisisobutyronitrile. Particularly preferred are organic peroxides whose temperature for 10 hours is 70-170°C, preferably 80-140°C. The amount of thermal polymerization initiator used is (A) above,
0.1 to 100 parts by weight of (B), (C) and other polymerizable prepolymers and reactive diluents used
10 parts by weight is preferred. If the amount is less than 0.1 part by weight, curing in shadow areas that are not exposed to light will be delayed, and if it exceeds 10 parts by weight, the storage stability of the composition will be poor. In the composition of the present invention, talc, alumina, silica, titanium oxide, aluminum hydroxide, calcium carbonate,
Inorganic fillers such as glass powder and thixotropic agents such as fumed silica are used in the composition. The total amount of each component (A), (B), and (C) mentioned above, as well as other polymerizable prepolymers and reactive diluents used: 100
In the case of an inorganic filler, it may be added within 300 parts by weight, and in the case of a thixotropic agent, it may be added within a range of 10 parts by weight. By using an inorganic filler or a thixotropic agent within the above range, the coating workability of the composition can be improved, but if it is used in excess of the above range, the viscosity of the composition will become too high, which may actually impair the coating workability. I don't like it because it makes it worse. Furthermore, to improve the storage stability of the composition, polymerization inhibitors such as hydroquinone, hydroquinone monomethyl ether, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), and phenothiazine are added for coloring. Various dyes and pigments may be added as long as they do not impair the performance of the composition (photopolymerizability, thermal polymerizability, adhesive strength, etc.). (Example) The present invention will be explained below with reference to Examples, and all parts and percentages in the specification are expressed on a weight basis. Examples 1 to 3 100 parts by weight of the unsaturated polyester resin listed in Table 1, 50 parts of tetrahydrofurfuryl methacrylate (THFMA), 50 parts of 2-hydroxyethyl methacrylate (2-HEMA), 30 parts of 1,6-hexanediol diacrylate parts, benzoin ethyl ether (BEE) 3 parts, tertiary butyl perbenzoate (TBPB) 5 parts, average particle size 4μ
An adhesive composition of the present invention was prepared by blending 130 parts of silica powder, and the adhesive strength of each was measured. To measure the adhesive strength, apply approximately 2 mg of adhesive per chip onto a paper phenol substrate, place the various chip parts listed in Table 2 on top, and then use a high-pressure mercury lamp (Toskiyur 400HC 0411 model [KK Toshiba)]. 60
The adhesive was cured by irradiation for seconds, and the adhesive force per chip was measured using a push-pull gauge. The results are shown in Table 2.

【table】

[Table] *marked Comparative example of destruction of chip parts 1 Same as Examples 1 to 3 except that epoxy acrylate resin (Epoxy Ester 3002A [manufactured by Kyoeisha Yushi Kagaku Kogyo Co., Ltd.]) was used instead of unsaturated polyester resin. An adhesive composition was prepared in the same manner,
Adhesive strength was measured under the same conditions as Examples 1-3. The results are shown in Table 2. Comparative Example 2 Example 1 except that urethane acrylate resin (Goserac 7000B [manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd.]) was used instead of the unsaturated polyester resin.
An adhesive composition was prepared in the same manner as in Examples 1 to 3, and the adhesive strength was measured under the same conditions as in Examples 1 to 3. The results are shown in Table 2. Examples 4 to 6, Comparative Examples 7 to 8 Adhesive compositions shown in Table 3 were prepared, and Example 1
The adhesive strength was measured in the same manner as in 3. Note that a cylindrical (1/4 watt) chip resistor was used as the chip component. The results are also shown in Table 3.

【table】

[Table] (Note) Numbers in the recipe table represent parts.
*The silica powder is the same as that used in Examples 1-3.
(Effects of the Invention) As described above, the composition of the present invention cures rapidly under the action of both light and heat and has excellent adhesive properties to various adherends, so it is useful for fixing chip parts, etc. It is extremely useful because it improves adhesive workability and facilitates automation of production lines.

Claims (1)

[Scope of Claims] 1 (A) an unsaturated polyester resin, (B) a monomer containing a tetrahydrofuran ring represented by the following general formula; [However, in the formula, n is an integer of 0 to 4, and R ₁ and R ₂ represent hydrogen or a methyl group. ] (C) hydroxyalkyl acrylate and/or hydroxyalkyl methacrylate, (D) photopolymerization initiator, (E) thermal polymerization initiator. An adhesive composition comprising the above (A), (B), (C), (D) and (E). 2 (A) For 100 parts by weight of unsaturated polyester resin,
The total amount of (B) tetrahydrofuran ring-containing monomer and (C) hydroxyalkyl acrylate and/or hydroxyalkyl methacrylate is 20~
200 parts by weight of the adhesive composition according to claim 1. 3. The adhesive composition according to claim 1, wherein (B) the tetrahydrofuran ring-containing monomer and (C) hydroxyalkyl acrylate and/or hydroxyalkyl methacrylate are used in a weight ratio of 1:9 to 9:1. .