JPH0423875A - Adhesive composition for temporary fixation - Google Patents

Abstract

PURPOSE:To provide the title composition removable with water, capable of easily and quickly performing the exchange works for electronic parts, comprising a water-absorptive monomer having ethylenic double bond, water-soluble polymer and water-nonabsorptive oligomer having ethylenic double bond. CONSTITUTION:The objective composition causing no slippage or debonding of electronic parts in their final bonding, comprising (A) a monomer having in the molecule at least one ethylenic double bond and convertible into a water- absorptive or water-soluble polymer when polymerized (e.g. N-vinyl-2- pyrrolidone), (B) a total of 100 pts.wt. of a water-absorptive and/or water-soluble polymer(s) (e.g. polyethylene glycol), (C) 0.1-25 pts.wt. of an oligomer or prepolymer having, in one molecule, at least one ethylenic double bond and convertible into a water-nonabsorptive or water-insoluble polymer when polymerized, and (D) 0.01-10 pts.wt. of a polymerization initiator.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an adhesive composition used for temporarily fixing electronic components such as (1) and (C) before soldering them onto a printed circuit board. In particular, after temporarily fixing, the electronic components do not shift or fall off during soldering, and when the temporarily fixed electronic components are removed for replacement etc., they can be easily removed by simply immersing them in water or hot water. The present invention also relates to an adhesive composition for temporary fixing that can be quickly removed and that can also easily remove adhesive remaining on a printed circuit board.

[Conventional technology]

When soldering electronic components such as 1 and C onto a printed circuit board, it is first necessary to temporarily fix the electronic components to prevent them from shifting or falling off before soldering.

Conventionally, cyanoacrylate adhesives have been used as adhesives for such temporary fixing.

[Problem that the invention seeks to solve]

However, with this adhesive, the adhesive flows out from the gap between the electronic component and the printed circuit board, resulting in insufficient temporary fixation and causing the electronic component to shift or fall off during soldering, making the soldering process difficult. It becomes difficult.

Further, after the electronic component is temporarily fixed on the printed circuit board, if the electronic component must be replaced for repair or the like, the electronic component must be removed from the printed circuit board. However, this removal requires heating at a temperature of 150°C for several tens of minutes for sushi, which not only makes the removal work troublesome, but also causes the electronic parts to deteriorate due to this heat.
damage or other losses. Furthermore, even after removing electronic components, the adhesive remaining on the printed circuit board must be removed by cleaning with an organic solvent, which also makes the removal process troublesome. This will introduce the deterioration of the working environment caused by solvents.

Therefore, an object of the present invention is to prevent the electronic components from shifting or falling off during soldering after temporarily fixing the electronic components on the printed circuit board, and to remove the temporarily fixed electronic components from the printed circuit board for replacement etc. This adhesive for temporary fixing can be easily and quickly removed by simply immersing it in water or hot water, and any residual adhesive on the printed circuit board can be washed away, improving the shortcomings of the aforementioned known technologies. An object of the present invention is to provide a drug composition.

[Means for solving problems]

In order to achieve the above-mentioned object, according to the present invention, in an adhesive composition used for temporarily fixing electronic components before soldering the electronic components onto a printed circuit board, the following components (A), (B), (C) and (b) That is, (A) A monomer that has at least one polymerizable ethylenic double bond in the molecule and whose polymer can become water-absorbing or water-soluble (B) Water-absorbing water-soluble and/or water-soluble polymeric substances.

(C) An oligomer or prepolymer having at least one ethylenic double bond in the molecule and capable of making the polymer non-water-absorbing or water-insoluble. (D) A polymerization initiator.

Further, according to the present invention, in addition to the above-mentioned components (A), (B), (C) and (D), it contains an inorganic filler as component (E). do.

Specific examples of the aforementioned component (A) include N-vinyl-2-pyrrolidone, N,N-dialkylaminoalkyl (meth)acrylic acid, such as N%N-dimethylaminoethyl acrylate, and N,N-dialkyl. Amino (
meth)acrylic acid amides, such as N,N-diacrylic acid amide; Examples include acid amides.

In addition to the homopolymers and copolymers of component (A), the component (B) may include, for example, polyethylene glycol, polyethylene oxide, alginic acid, salts of alginic acid, carboxymethylcellulose, hydroxyethylcellulose, methylcellulose, methylcellulose, Ethylcellulose, poly(meth)acrylic acid, salts of poly(meth)acrylic acid, polyvinyl alcohol, polyvinyl ether, polyethyloxazoline, vinylpyrrolidone-vinyl acetate copolymer, methyl vinyl ether maleic anhydride copolymer, starch, gelatin, agar etc. It is preferable that these components are dissolved in the component (A), but are completely or partially insoluble and are dissolved in the component (A).
A) may be dispersed in the material. In addition, component (B
) may be a substance that has both water-absorbing and water-soluble properties, or may have either property alone.

Specifically, the component (C) is, for example, isobornyl (meth)acrylate, dicyclopentenyl (meth)
Acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, 1,6-hexanethiol di(meth)acrylate, pentaerythritol tri(meth)acrylate, tris[2-(meth)ally [oxyethyl] isocyanurate, dipentaerythritol monohydroxypenta(meth)acrylate, bisphenol A epoxy (
Examples include meta)acrylate.

Further, as the component (D), for example, a photopolymerization initiator,
Examples of the photopolymerization initiator include redox polymerization initiators, such as benzophenone, acetophenone, Michler's ketone, benzyl, benzoin,
Examples include benzoin methyl ether, benzoin ethyl ether, tetramethylthiuram sulfide, thioxane trichlorothioxanthone, benzyl dimethyl ketal, methyl benzoyl formate, and in addition to these photopolymerization initiators, a sensitizer may be used as necessary. You can also do that. The redox polymerization initiator is a redox catalyst containing an organic peroxide and a reducing agent, such as a combination of a ketone peroxide such as methyl ethyl ketone peroxide or methyl cyclohexanone peroxide and a metal soap such as cobalt naphthenate or copper naphthenate. combination, or diacyl peroxide such as octanoyl peroxide, benzoyl peroxide, and 3 such as N,N-dimethylaniline, N,N-dimethyl-P-)luidine, etc.
Examples include a combination with a grade amine, or a combination of a hydroperoxide such as cumene hydroperoxide or diisopropylbenzene hydroperoxide with an organic thiourea such as thiourea or ethylenethiourea. Note that component (D) can also be a combination of a photopolymerization initiator and a redox polymerization initiator.

The blending ratio of the components (A) and (B) is arbitrary, but in order to increase the viscosity, a large amount of component (B) is blended,
To lower the amount of component (B), add less component (B).
The desired viscosity can be adjusted by changing the amount of .

The amount of component (C) added is 0.1 to 25 parts by weight per 100 parts by weight of the total amount of component (A) and component (B),
Preferably it is 5 to 15 parts by weight. If it is too small, the electronic components may shift or fall off during soldering, and if it is too large, the water solubility of the cured product decreases, reducing workability when removing the electronic components.

In addition, the amount of the above component mark) is for component (A) and component (B).
A total amount of 10,000 parts by weight, 0. OL-.10 parts by weight, preferably 1 to 5 parts by weight.

The present invention comprises the components (A), (B), (C) and (D).
In addition to this, by further containing an inorganic filler, it becomes easier to adjust the viscosity of the adhesive composition. Further, it becomes possible to impart thixotropy to the adhesive composition, and workability when handling the adhesive can be improved.

As such an inorganic filler, a water-dispersible filler such as a silica filler is preferable, and a filler in which hydroxyl groups remain on the surface of the filler particles is more preferable. There are no limitations.

Furthermore, in the present invention, a polymerization inhibitor such as hydroquinone, catechol, 2,6-di-tert-butyl-P-cresol, etc. can be used for the purpose of improving storage stability, if necessary.

[Effect]

The viscosity of the above-mentioned composition of the present invention can be freely adjusted by changing the blending amount of component (B) with respect to component (A), and therefore,
For example, even if an electronic component is warped and a large gap is formed between it and the printed circuit board, adjusting the viscosity to a high level will hold it in the gap and prevent it from flowing out of the gap like traditional cyanoacrylate adhesives. There is no storage, and temporary fixation is sufficient to prevent electronic components from shifting or falling off. Furthermore, the combination of components (A), (B), and (C) increases the adhesive strength for temporary fixing, prevents electronic components from shifting or falling off during soldering, and increases the water absorption or water solubility of the cured product. This increases work efficiency by eliminating the need to remove electronic components.

Furthermore, by incorporating an inorganic filler into the composition of the present invention, the above-mentioned viscosity adjustment becomes easier, and it becomes possible to impart thixotropy to the adhesive composition of the present invention, thereby improving workability during handling.

[Embodiments of the invention]

Adhesive composition samples Nα1 to 5 with the formulation shown in Table 1 below
mixed and adjusted. Among these, samples Nα1-2 are compositions according to the present invention (examples), samples Nα3-5 are comparative examples, and in particular sample N (L5 is a conventional ethyl cyanoacrylate adhesive alone).

Temporary fixation tests as shown in FIGS. 1 and 2 were conducted using each of the sample adhesives shown in Table 1.

FIG. 1 is a plan view showing a state in which an electronic component is temporarily fixed to a printed circuit board, and FIG. 2 is a sectional view of FIG. 1. As shown in FIGS. 1 and 2, adhesives 2 of each sample Nα1 to 5 in Table 1 are applied on a printed circuit board 1,
The electronic component 3 was placed on top of this. Next, samples Nα1 to 4
15 in height using a high-pressure mercury lamp (4KW).
The electronic component 3 was temporarily fixed on the printed circuit board 1 by irradiating the electronic component 3 with ultraviolet rays from a cm wavelength for 20 seconds. Humidity 60 for sample Arashi 5
%, and was temporarily fixed by being left for 24 hours at a temperature of 25°C.

Each of the above samples was tested for solder heat resistance and underwater removability. Solder heat resistance test is 2
Each of the temporarily fixed samples described above was immersed twice for 3 seconds in a solder bath at a temperature of 60° C., and the electronic components 3 were visually observed for lifting, displacement, etc. Moreover, regarding removability, each sample was immersed in stirred warm water at a temperature of 80° C. and the state of peeling was observed. The results are shown in Table 2.

As is clear from Table 2, sample N according to the composition of the present invention
[L l and 2 show satisfactory values for both solder heat resistance and removability.

〔Effect of the invention〕

As described above, the adhesive composition of the present invention prevents electronic components from shifting or falling off during main bonding with solder, and can be easily removed with water, improving workability when replacing electronic components. This is promising and does not require cleaning with organic solvents, so the working environment is also good.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing how electronic parts are mounted, and FIG. 2 is a sectional view of FIG. 1. 1. Printed circuit board, 2. Adhesive 3. Electronic parts.

Claims (3)

[Claims] (1) In an adhesive composition used for temporarily fixing electronic components before soldering them onto a printed circuit board, the following components (A), (B), (C) and (D) are used.
An adhesive composition for temporary fixing, comprising: (A) A monomer that has at least one polymerizable ethylenic double bond in its molecule and that allows the polymer to be water-absorbing or water-soluble. (B) Water-absorbing and/or water-soluble polymeric substances. (C) An oligomer or prepolymer that has at least one ethylenic double bond in its molecule and can be non-water-absorbing or water-insoluble. (D) Polymerization initiator. (2) In the composition according to claim 1, the component (A
) and (B), the amount of component (C) used is 0.1 to 25 parts by weight, and the amount of component (D) used is 0.01 to 10 parts by weight. An adhesive composition for temporary fixing. (3) The composition according to claim 1, further comprising an inorganic filler as component (B) in addition to the components (A), (B), (C), and (D). An adhesive composition for temporary fixing.