JPH036279A - Adhesive - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an adhesive used for adhesively mounting electrical components on sealed circuit boards such as optical components and hollow LSI packages using glass or ceramics. It is related to.

[Conventional technology]

Traditionally, epoxy resin adhesives that use phenolic resin as a curing agent and contain organic acids or imidazole, organic amine compounds, and fillers have been used to bond electronic components such as sealing hollow LSI packages. . Among electronic components, liquid crystal cells are manufactured using the above-mentioned adhesive, for example, in the following manner. That is, as shown in FIG. 1, a glass plate 1 is divided into four areas, a light emitting element 7 is placed in each area, and an epoxy resin adhesive (hatched area) 2 is applied to a thickness of 5 μm by screen printing. After volatilizing the solvent in the adhesive, another glass plate is bonded by thermocompression bonding. In the figure, 3 is a liquid crystal injection port. Next, the four glass plate adhesive products are divided into four pieces along the broken line. Then, as shown in FIG. 2, after injecting liquid crystal 8 from the liquid crystal injection port 3 into the divided glass plate adhesive product, a reflecting plate 6 and a polarizing plate 5 are provided on both outer surfaces of both glass plates 1.4. It is made by

[Problem that the invention seeks to solve]

However, if the above-mentioned epoxy resin adhesive is left in a high-temperature atmosphere or in a high-temperature atmosphere after being cured, gases generated from unreacted components, such as organic acids and lower amine compounds, may cause optical components such as 2. element,
This poses a problem in that it has an adverse effect on parts constituting electronic parts such as liquid crystals. In other words, impurities such as the above-mentioned gases cause corrosion of elements, aluminum wiring of substrates, etc., poor conductivity of contact parts such as relays, corrosion of chip parts, etc. Among the inorganic fillers used as the above-mentioned fillers, especially moisture adsorbed to particles with a particle size of 10 μm or less (for example, aluminum oxide powder contains about 5% by weight, and silica powder contains about 2% by weight). ) has an adverse effect on the curing reaction rate (decreased adhesive strength). Furthermore, a problem arises in that the power consumption of the resulting liquid crystal cell increases due to the influence of the low molecular weight oligomers and monomers contained in the phenol resin. This goes against the advantage of low power consumption of the liquid crystal cell, and as a result, reduces the commercial value of electrical products using this liquid crystal cell.

In addition, such epoxy resin adhesives have low viscosity and long gelation times, so they have problems with screen printing, such as misalignment during adhesion and inability to control the thickness of the adhesive layer during screen printing. Furthermore, there is another problem in that the operating reliability of the electronic device after sealing is reduced due to variations in adhesive strength.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide an adhesive having excellent impact resistance, screen printability, and adhesive strength.

[Means for solving problems]

In order to achieve the above object, the adhesive of the present invention contains the following components (A) to (G), and the amount of component (B) is (
A) 10 to 50 parts by weight per 100 parts by weight of component, (C
The composition is such that the amount of component (D) is set to be 20 to 60 parts by weight, and the amount of component (E) is set to be 40 to 80 parts by weight. .

(A) Epoxy resin.

(B) Novolac type phenolic resin with a softening point of 80°C or higher.

(C) the content of particles with a particle size of 2 μm or less is 95% by weight or more,
Aluminum oxide powder with an adsorbed moisture content of 2% by weight or less.

(D) the content of particles with a particle size of 6 μm or less is 95% by weight or more,
Silica powder with an adsorbed moisture content of 0.2% by weight or less.

(E) An organic solvent represented by the following general formula.

R+ 0CtHtORt (F) Imidazole compound.

(G) Silane coupling agent.

[Effect]

That is, in order to achieve the above object, the present inventors
A series of studies were conducted. In the course of this research, we found that one of the causes of variations in the curing characteristics of epoxy resin adhesives is the moisture contained in the phenolic resin used as a component raw material, phenolic compounds (low molecular oligomers, monomers), and inorganic fillers. It was discovered that moisture and organic solvents adsorbed on the agent had a major influence, and that these had an adverse effect on curability. As a result of further research focusing on the above-mentioned phenolic resin, inorganic filler, and organic solvent, we found that the above-mentioned phenolic resin has a softening point of 80°C.
If the above is used as an inorganic filler with an adsorbed moisture content below a specific value, and further as an organic solvent, each component is used in a specific ratio to the epoxy resin that is the base resin. The present invention was achieved by discovering that excellent impact resistance, screen printability, and adhesive strength can be obtained.

The adhesive of the present invention comprises an epoxy resin (component A), a specific novolak phenolic resin (component B), a specific aluminum oxide powder (component C), and a specific silica powder (component C).
It is obtained by using a specific organic solvent (component E), an imidazole compound (component F), and a silane coupling agent (component C) in specific proportions.

The epoxy resin of component A is not particularly limited, and conventionally known epoxy resins may be used, such as bisphenol A type.

The novolac type phenol resin of the above component B acts as a curing agent for the epoxy resin of the above component A, and includes those commonly used. As the novolac type phenolic resin for component B, one with a softening point of 80°C or higher must be used in a blending ratio of 10 to 50 parts per 100 parts by weight (hereinafter abbreviated as "parts") of the epoxy resin for component A. Must be. As mentioned above, the softening point is 80℃
As a method of obtaining the above, for example, as a pretreatment, 6
An example of this method is heating at 170 to 180°C for 1 hour under a reduced pressure of 0 mml (g). By performing the above pretreatment, not only water but also phenolic compounds of low molecular weight oligomers and monomers contained in the novolac type phenolic resin are removed. By removing the above substances,
The adhesive strength of the resulting adhesive can be improved and adverse effects on elements, liquid crystals, etc. can be eliminated.

As the specific aluminum oxide powder of the above-mentioned C component, there is used one having a particle diameter of 2 μm or less, a content of 95% by weight (hereinafter abbreviated as "%") or more, and an adsorbed moisture content of 2% or less. The blending amount of component C must be set in the range of 20 to 60 parts per 100 parts of the epoxy resin of component A.

The specific silica powder with the above components has a particle size of 6 μm.
The following content is 95% or more and the adsorbed moisture content is 0.2%
The following are used: The blending amount of the above-mentioned components must be set within a range of 5 to 40 parts based on the epoxy resin of component A.

In addition, as a method for obtaining components C and D having the above adsorbed moisture content, for example, a method of heating at a temperature of 150° C. or higher for 3 hours or longer as a pretreatment can be mentioned.

Furthermore, as the specific organic solvent for the above-mentioned component E, those represented by the following general formula are used, such as butyl cellosolve and the like.

R+ 0CJ40 Rz The blending amount of the E component must be set in the range of 40 to 80 parts per 100 parts of the epoxy resin of the A component.

The imidazole of component F acts as a curing accelerator, and examples include 2-ethyl-4-methylimidazole. And, as for the blending amount of the above F component,
0.3 to 3 parts 0 per 100 parts of epoxy resin as component A
It is preferable to set it within a range.

The silane coupling agent for component C is not particularly limited, and conventionally known ones can be used. The amount of component C to be blended is preferably set in the range of 3 to 30 parts per 100 parts of the epoxy resin of component A.

The adhesive of the present invention can be produced using the above-mentioned components, for example, in the following manner. That is, among the above-mentioned components, aluminum oxide powder as component C and silica powder as component D are heated at 150° C. or higher for 3 hours to set the respective adsorbed moisture contents to below specific values. In addition, the novolac type phenolic resin of component B is heat-treated at 170° C. for 1 hour or more under a reduced pressure of 60 plates of Hg or less to set the softening point to 80° C. or more. Next, the heat-treated component B and the epoxy resin and organic solvent of component A are mixed, cooled, and then filtered through a filter to prepare a resin solution. and,
The above-mentioned heat-treated components C and D are blended into this resin solution, heated and mixed, and then cooled.
It can be produced by mixing an imidazole compound as a component and a silane coupling agent as a component C.

The adhesive thus obtained uses a novolak type phenolic resin with a softening point of 80°C or higher, an inorganic filler with an adsorbed moisture content of less than a specified value, and a specified organic solvent. Since the components are blended in specific proportions, it has excellent impact resistance and screen printability, as well as high adhesive strength (700 kg/c+f1 or more). Therefore, liquid crystal cells, hollow LSI
Ideal as an adhesive for sealing packages, etc.

〔Effect of the invention〕

As described above, the adhesive of the present invention contains aluminum oxide powder and silica powder, which are the specific inorganic fillers mentioned above, as well as a specific novolac type phenolic resin and an organic solvent. Excellent impact resistance, screen printability, and adhesive strength. Therefore, it is useful for sealing large-sized liquid crystal cells, and high actuator conversion properties can be obtained in electrical products such as liquid crystal televisions manufactured using this liquid crystal cell. It is also ideal for forming passivation films.

Next, examples will be described together with comparative examples.

First, prior to Examples, heat-treated aluminum oxide powder, silica powder, and novolac type phenol resin were prepared according to the following method.

(Heat treatment of aluminum oxide powder and silica powder) Aluminum oxide powder containing 95% or more of particles with a particle size of 6 μm or less and 500 g of silica powder containing 95% or more of particles with a particle size of 2 μm or less are uniformly placed in a porcelain vat. Then, heat treatment was performed at 150° C. for 3 hours using a hot air dryer. The weight loss rate at this time was 4.5% for aluminum oxide powder.
, silica powder was 1.4%. In addition, the adsorbed moisture content is 1.2% for aluminum oxide powder and 0 for silica powder.
．． It was 1%.

(Heat treatment of novolac type phenol resin) Novolac type phenol resin (Tamanol P-180, manufactured by Arayo Kagaku Co., Ltd.)
Put 300g into the same porcelain vat as above and add 10mm
1 g of the product was subjected to vacuum heat treatment and drying at 170° C. for 4 hours under reduced pressure. The weight reduction rate at this time was 4.8%. The softening point of the obtained novolac type phenolic resin was 83°C.

[Examples 1 to 6, Comparative Examples 1 to 3] Epoxy resin and butyl cellosolve were charged into a glass container equipped with a heating device and a stirring device in the proportions shown in the table below, heated to 70°C to dissolve, and uniformly dispersed. The above-mentioned heat-treated novolac type phenol resin was blended with this, dissolved and cooled, and then filtered through a 4 μm filter to prepare a resin solution. The heat-treated aluminum oxide and silica powder were added to 180 g of this resin solution in the proportions shown in the same table, heated to 50 to 80°C, mixed, and cooled. Then, 2 parts of 2-ethyl-4-methylimidazole and 10 parts of a silane coupling agent were added and mixed to this at 30° C. or lower to obtain an adhesive.

The viscosity, gelling time, and adhesive strength of the obtained adhesive at 25°C were measured, and the results are shown in the same table.

In addition, the said adhesive force was measured as follows.

Adhesive Strength Two iron cylinders were prepared, one end surface (diameter 11.28 mm) of each cylinder was well polished with #400 abrasive paper, and an adhesive was applied to this surface. Next, after drying at 90″C for 30 minutes, the coated surfaces were pasted together at 2.5 kg/c.
It was cured at 150° C. for 90 minutes under a pressure of J. The simple adhesive strength (kg/ci) was measured by pulling this at room temperature at a pulling speed of 5 mm/min.

(The following is a blank space) From the above table, it can be seen that the comparative product has a long gelation time and an adhesive strength of less than 600 kg/cd. In comparison, the example product had a short gelation time and adhesive strength of 750 kg/c.
It can be seen that the adhesive strength is superior to that of ifi, and the adhesive strength is excellent.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram of a state in which an adhesive is applied on a glass plate by screen printing, and FIG. 2 is a longitudinal sectional view of a display cell.

Claims (1)

[Claims] (1) Contains the following components (A) to (G), in which the amount of component (B) is 10 to 50 parts by weight per 100 parts by weight of component (A), and the amount of component (C) is 20 to 50 parts by weight. 60 parts by weight, (D)
An adhesive characterized in that the blending amount of the components is set to be 5 to 40 parts by weight, and the blending amount of component (E) is set to be 40 to 80 parts by weight. (A) Epoxy resin. (B) Novolac type phenolic resin with a softening point of 80°C or higher. (C) the content of particles with a particle size of 2 μm or less is 95% by weight or more,
Aluminum oxide powder with an adsorbed moisture content of 2% by weight or less. (D) the content of particles with a particle size of 6 μm or less is 95% by weight or more,
Silica powder with an adsorbed moisture content of 0.2% by weight or less. (E) An organic solvent represented by the following general formula. R_1-OC_2H_4O-R_2 [In the above formula, R_1 is H or CH_3CO, and R_2 is C_nH_2_n_+_
It is an alkyl group represented by 1. ] (F) Imidazole compound. (G) Silane coupling agent.