JPS6296580A - Fire-retardant adhesive - Google Patents

Abstract

PURPOSE:To improve the adhesion, heat aging resistance, electrical char acteristics, workability, etc., by blending a satd. copolymer polyester resin, a brominated org. fire retardant, an inorg. filler, and an org. solvent in particu lar proportions. CONSTITUTION:The titled adhesive contains 10-50pts.wt. satd. copolymer polyester resin, 5-30pts.wt. brominated org. fire retardant, 1-30pts.wt. inorg. filler, and 50-85 org. solvent. The satd. copolymer polyester resin has a molecular weight of 15,000-25,000. Examples of the brominated org. fire retardant include decabromodiphenyl oxide and hexabromobenzene. Examples of the inorg. filler as a fire retardant additive include calcium carbonate, aluminum silicate, and antimony trioxide. Examples of the org. solvent include acetone, methyl ethyl ketone, and cyclohexanone. The titled adhesive is suitable for use in fixation of electronic components.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid adhesive for fixing electronic components, and particularly to a flame-retardant adhesive having excellent flame-retardant properties.

[Summary of the invention]

The present invention has achieved flame retardant properties by selecting a saturated copolymerized polyester resin, a brominated organic flame retardant, an inorganic filler, and an organic solvent as components of a liquid adhesive for fixing electronic parts, and mixing these in a predetermined ratio. The object of the present invention is to provide a flame-retardant adhesive that has excellent electrical properties and less deterioration of properties even after aging.

[Conventional technology]

Adhesives commonly used for fixing electronic components include:
A typical example is chloroprene adhesive. However, this chloroprene adhesive, for example,
When heated and aged for 24 hours at ℃, it turns black and carbonizes, and also has the disadvantage that its electrical insulation properties decrease because it absorbs humidity in the air. Therefore, it is particularly inconvenient for fixing electronic components that have a large capacity and generate a certain amount of heat.

Therefore, flame-retardant silicone adhesives have been developed as adhesives that do not have the above-mentioned drawbacks. However, although this flame-retardant silicone adhesive has excellent flame retardancy, it has low adhesive strength and has rubber-like flexibility, making it unsuitable for fixing large parts.

Furthermore, with this flame-retardant silicone adhesive, reaction products form a film on the metal surface, causing poor conductivity.
It has the disadvantage of sometimes corroding metals and being expensive.

[Problem that the invention seeks to solve]

Therefore, the object of the present invention is to obtain an adhesive that improves the various drawbacks mentioned above. That is, the object is to provide a flame-retardant adhesive that is not only excellent in heat aging stability but also in electrical properties (electrical insulation, etc.), adhesive properties, workability, and the like.

[Means for solving problems]

In order to achieve this object, the flame retardant adhesive of the present invention contains 10 to 50 parts by weight of a saturated copolymerized polyester resin, 5 to 30 parts by weight of a brominated organic flame retardant, 1 to 30 parts by weight of an inorganic filler, and It is characterized by containing 50 to 85 parts by weight of an organic solvent.

The flame retardant adhesive of the present invention has a saturated copolymerized polyester resin as its main component, and a brominated organic flame retardant as a flame retardant and an inorganic filler are added and mixed therein, and the viscosity, chicken tropism, etc. are adjusted using an organic solvent. It is controlled and molded for one use.

The above saturated copolymerized polyester resin has a molecular weight of 1soao.
~25,000 is used, and its volume resistivity is 1X1013Ω.

Further, the saturated copolymerized polyester resin is a raw material that is the main component of the flame-retardant adhesive, and influences the basic properties such as viscosity and adhesive strength of the final product.

In general, this type of adhesive needs to have good workability during use, for example, there should be little stringiness of the adhesive when extruded from a narrow nozzle, and It is necessary to have adequate viscosity and thixotropy so that there is little dripping. Therefore, in the present invention, it is necessary that the solid content is 20 to 50% and the viscosity is 100 cps = 100000000 cps when the saturated copolymerized polyester resin and organic solvent are dissolved. Furthermore, the final viscosity obtained by adding a brominated organic flame retardant and an inorganic filler to the saturated copolymerized polyester resin solution of the main component is 1000 to 2QO.
OOOcps - preferably 10000-100000c
It is ps. This viscosity range greatly affects the stringiness and sag properties when using a liquid adhesive.

The content of the saturated copolymerized polyester resin is set to 10 parts by weight to 50 parts by weight in view of the amounts of each component to be added later. If the content of the saturated copolymerized polyester resin is less than 10 parts by weight, the adhesive strength will decrease, and if it exceeds 50 parts by weight, flame retardation will become difficult.

On the other hand, the above-mentioned brominated organic flame retardant is blended in a necessary amount so that the solid content after drying with the solvent maintains flame retardancy. Therefore, the content of the brominated organic flame retardant is 5 to 30
Part by weight. If the content is less than 5 parts by weight, it is difficult to achieve flame retardancy, and if it exceeds 30 parts by weight, problems such as a decrease in adhesive strength and cracking after curing will occur.

In the present invention, a brominated organic flame retardant with excellent thermal stability and high flame retardant effect even when added in small amounts is used as a flame retardant. 2,3-dibromopropyl)isocyanurate, 2,2-bis(4-
Hydroxy-3,5-dibromophenyl)propane, 2
．． Examples include 2=bis(4-hydroxyethoxy-3,5-dibromophenyl)propane.

Further, an inorganic filler as a flame retardant aid is added to the adhesive of the present invention, and examples of the inorganic filler include calcium carbonate, aluminum silicate, calcium fluoride, aluminum hydroxide, antimony dioxide, asbestos, Silicon dioxide, magnesium oxide, aluminum oxide, titanium oxide, silica-alumina, etc. can be used. By adding these inorganic fillers as flame retardant aids, the amount of expensive tit flame additive added can be reduced. Also,
The blending amount of this inorganic filler affects its function as a flame retardant aid and work properties such as stringiness and sagging prevention, and in particular, excessive addition results in a decrease in adhesive properties. Therefore, the amount of the inorganic filler blended is 1 to 30 parts by weight.

Each of the above raw materials is mixed with an organic solvent to prepare a flame-retardant adhesive. Examples of organic solvents used include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isopropanol, n-hexane, and toluene. , xylene, cyclohexane, methyl cellosolve, ethyl acetate, trichlorethylene, 1,1.1
-Trichloroethane and the like are preferred.

Furthermore, a curing agent may be added in addition to the above-mentioned components. As a curing agent, a polyfunctional compound such as 2,44-lylene diisocyanate, 2,6-)lylene diisocyanate, diphenylmethane-4,4゛-diisocyanate, polymethylene polyphenyl diisocyanate, and hexamethylene diisocyanate is used. Isocyanates, mixtures thereof, isoneanates modified with polyols, carbodiimides, alcohols, phenols,
Blocked isocyanate masked with amine etc. can be used. In addition, various amines, imidazole, methylenebisorthoaniline,
It is also possible to use dibutylsilaurylate or the like in combination. The amount of these curing agents added is 0.1 to 10 parts by weight.

The flame-retardant adhesive of the present invention not only has good flame retardancy and excellent electrical properties 5 adhesiveness, etc., but also has etching resistance (
Since it has excellent properties such as alkali resistance), flexibility, and beer strength, it can be applied not only to fixing electronic components but also to flexible printed wiring boards, for example.

That is, polyester films and polyimide films are typical substrate materials for flexible printed wiring boards, but when these films are used, they have the following drawbacks. For example, polyester films are flammable and cannot be used as is in applications requiring flame retardancy. Alternatively, although polyimide film has no problem with flame retardancy, it undergoes large dimensional changes due to moisture absorption and has poor alkali resistance, so it cannot be used with inkjet.
It had the disadvantage that it would dissolve when soaked in the alkaline ink used for flat-type pulling.

Therefore, by using the flame retardant adhesive of the present invention,
Inexpensive polyester film is made flame retardant, IT=resistant, and alkali resistant. It becomes possible to provide a flexible printed wiring board with excellent dimensional stability.

Specifically, the flame-retardant adhesive of the present invention is applied to one side of a polyester film, a copper foil for forming a predetermined printed circuit wiring is attached, and a flame-retardant adhesive of the present invention is applied to the opposite side of the film. It can be coated with a combustion treatment agent.

Examples of the flame retardant treatment agent include halogen-containing condensed phosphoric acid esters such as trischloroethyl phosphate and trisdichloropropyl phosphate. These halogen-containing condensed phosphoric acid esters are applied together with a binder such as a saturated polyester resin or a bisphenol-type Epoquine resin, and a curing agent such as isocyanates or amines.

[Effect]

The saturated copolymerized polyester resin controls the basic properties of the final product, such as viscosity and adhesive strength, thereby ensuring heat aging stability, electrical properties, and adhesive strength.

The brominated organic flame retardant functions to impart flame retardancy to the solid content after drying the organic solvent. The inorganic filler functions as a flame retardant aid and also plays the role of adjusting the thixotropic properties of the adhesive. Organic solvents also contribute to adjusting the viscosity and thixotropy of the final product.

〔Example〕

Next, specific examples of the present invention will be described, but the present invention is not limited to these examples.

Example 1.

Ethylene glycol 124 parts by weight Dimethyl terephthalate 97 parts by weight Dimethyl sebacate 101 parts by weight Calcium acetate
0.15 parts by weight The above composition was transesterified at 160 to 200°C for 120 minutes while passing an inert gas, and then the reaction was continued at 275°C for 120 minutes under a low pressure of 1 mm/1 g to obtain a saturated intrinsic viscosity of 0.62. A copolymerized polyester resin was obtained. This was designated as resin A.

Next, Resin A 20 parts by weight Decabromodiphenyl oxide 10 parts by weight Antimony dioxide 5 parts by weight Silica-alumina powder
5 parts by weight toluene
A mixture consisting of 30 parts by weight of methyl ethyl ketone was stirred and dissolved to give a viscosity of 1500 cp.
s, a viscous liquid with a solid content of 40% was obtained.

This viscous liquid was applied on the interdigitated electrodes of the glass epoxy laminate specified in JIS Z-3197, 4, 10,
When the insulation resistance was measured after 24 hours under the conditions of 20℃ and 65% relative humidity, the insulation resistance value was 0.29X1
The insulation resistance value of this sample after heat aging at 150°C for 7 days was 1.3 x 10'Ω, 4
The insulation resistance value after aging for 7 days at 0° C. and 90% relative humidity was 0.92×10”Ω, with almost no deterioration observed.

Example 2 Dimethyl terephthalate 97 parts by weight Dimethyl adipate 18 parts by weight Dimethyl sebacate 80 parts by weight ethylene glycol
12431i 1 part calcium acetate
0.15 parts by weight The above composition was transesterified at 160 to 200°C for 120 minutes while passing an inert gas, and then the reaction was continued at 275°C under a low pressure of 1111 g for 120 minutes to obtain a saturated intrinsic viscosity of 0.58. A copolymerized polyester resin was obtained. This was designated as resin B.

Next, Resin 8 25 parts by weight Hexabromobenzene 15 parts by weight Silica powder
20 parts by weight toluene
32 parts by weight methyl ethyl ketone
A mixture consisting of 8 parts by weight was stirred and dissolved, and the viscosity was 150.
A viscous liquid with a solid content of 60% was obtained.

This viscous liquid was applied on the interdigitated electrodes of the glass epoxy laminate specified in JIS Z-3197, 4, 10,
When the insulation resistance was measured after 24 hours under the conditions of 20℃ and 65% relative humidity, the insulation resistance value was 2.5X10
The insulation resistance value of this sample after heat aging at 70℃ for 7 days was 0.56XIO''Ω at 40℃.
, the insulation resistance value after aging for 7 days at 90% relative humidity is 0.
．． At 82XLOIIΩ, almost no deterioration was observed.

On the other hand, when a chloroprene adhesive was used, the insulation resistance value after aging became a value of 1.0XIO''Ω or less, and a decrease in insulation resistance was observed.

Next, an application example in which the flame retardant adhesive of the present invention is applied to a flexible printed wiring board will be described.

Application example As shown in Figure 1, after coating a 25 μm thick polyester film (1) with a 10 μm thick flame retardant layer (2), 9 on the side! The film thickness of the flammable adhesive (3) after drying is 25 μm.
It was coated and dried so that the color was uniform, and then a 35-μm-thick piece (4) was heated to make it uniform.

The flame retardant layer (2) is made of saturated polyester resin 30
parts by weight, 70 parts by weight of trischloroethyl phosphate,
Hardening agent (manufactured by Nippon Polyurethane Co., Ltd., Millionate MR) 1
Parts by weight were mixed in a mixed solvent of toluene and methyl ethyl ketone to give a solid content of 40%, and this mixture was applied to a film thickness of 10 μm after drying, and the solvent was dried at 50°C.

After 24 hours, it was cured and formed.

The composition of the flame retardant adhesive is as follows.

Saturated copolymerized polyester resin 20 parts by weight (Resin A) Hexabromohenzene 10 parts by weight Silica powder 5 parts by weight Antimony dioxide 5 parts by weight Diphenylmethane diisocyanate 2i 1 part Toluene
30 parts by weight methyl ethyl ketone
28 parts by weight Using this as an application example, a flexible printed wiring board using ordinary polyester film was used as Comparative Example 11 A flexible printed wiring board using ordinary polyimide film was used as Comparative Example 2 to examine mechanical and electrical properties. . The results are shown in the table below. In addition, in the table, dimensional stability is determined by examining the change in dimension after boiling for one hour, and alkali resistance is determined by measuring the change in dimension after boiling for one hour, and alkaline resistance is determined by measuring the change in dimension after boiling for one hour.
The condition after immersion for 3 days was investigated. In addition, the flame retardancy is U
L (Underwriters' Laborat
ory) according to the standard.

(Leaving space below) From this table, it can be seen that in the application examples to which the flame-retardant adhesive of the present invention is applied, it has particularly excellent flame retardancy compared to those using ordinary polyester film, and that It can be seen that the dimensional stability and alkali resistance were improved compared to the case.

〔Effect of the invention〕

As is clear from the above description, the flame-retardant adhesive of the present invention, which is mainly composed of a saturated copolymerized polyester resin, a brominated organic flame retardant, an inorganic filler, and an organic solvent, is not only flame-retardant; The electrical insulation and adhesion properties after aging are disturbing. In particular, heat-aged adhesives such as chloroprene adhesives (
Because it does not cause deterioration of the electrical properties of adhesives or corrode metals like flame-retardant silicone adhesives, it is suitable for line assembly (components) of electronic mechanical products (e.g. television receivers, radio receivers, video tape recorders, etc.). It is useful as an insulator, adhesive, and sealant for mounting, assembly, etc.).

In addition, the flame-retardant adhesive of the present invention satisfies the beer strength, etching resistance, heat resistance, durability, flexibility, and dimensional stability of electrical properties necessary for a flexible circuit material.
For example, it is possible to provide a flame-retardant flexible circuit board made by converting an inexpensive polyester film into jI@.

[Brief explanation of drawings]

FIG. 1 is a schematic enlarged cross-sectional view of essential parts showing an example of the structure of a flame-retardant flexible printed wiring board using the flame-retardant adhesive of the present invention. Patent Applicant Sony Chemical Corporation Representative Patent Attorney Koike Mimi Jo Tamura

Claims (1)

[Claims] A flame-retardant adhesive characterized by containing 10 to 50 parts by weight of a saturated copolymerized polyester resin, 5 to 30 parts by weight of a brominated organic flame retardant, 1 to 30 parts by weight of an inorganic filler, and 50 to 85 parts by weight of an organic solvent. agent.