JPH0243259A - Thermoplastic resin composition for sealing electronic component - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent in soldering resistance and flow by mixing an aromatic polythioether ketone resin, a silicic filler and a fibrous filler. CONSTITUTION:This composition is constituted of 30-90wt.% aromatic polythioether ketone resin having repeating units of the formula, an inherent viscosity of, desirably, 0.2-0.6 (solvent: 98% sulfuric acid, concentration: 0.5g/dl, temperature: 25 deg.C), and preferably treated with an acid (e.g., an aqueous acetic acid solution at a pH of 4) or washed with hot water or an organic solvent (e.g., acetone) and having an Na content <=900ppm, 10-60wt.% silicic filler (e.g., fused silica) and 0-50wt.% fibrous filler (e.g., glass fiber).

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a resin composition comprising an aromatic polythioetherketone resin, a siliceous filler, and a fibrous filler, which has particularly excellent solder resistance and fluidity. The present invention relates to a thermoplastic resin composition for encapsulating electronic components.

[Conventional technology]

Conventionally, IC,! -Electronic components such as Lansistor diodes, capacitors, thyristor coils, and connectors must maintain electrical insulation, mechanical protection,
Thermosetting resins such as epoxy resins or silicone resins are used to prevent changes in characteristics due to external atmosphere.
Covering or sealing using transfer or compression molding methods is widely practiced.

However, these thermosetting resins have problems such as poor resin storage stability, a long molding cycle during sealing molding, and the inability to reuse the runner sprue.

Furthermore, in recent years, in order to solve the above-mentioned problems of thermosetting resins, polyphenylene sulfide resin, which is a thermoplastic resin, has been used for sealing in JP-A-52-149348 and JP-A-53-66°565. Publication No. 42 and U.S. Patent No. 42
It is disclosed in Japanese Patent No. 69756.

In addition, the aromatic polythioetherketone with the structure [1] has a high melting point (Tm = 350°C) and a high glass transition point (Tg = 145°C), and has good heat resistance, mechanical properties,
Excellent electrical properties and dimensional stability, and low water absorption.
Physically very good. It is also known to be a thermoplastic polymer that is insoluble in solvents other than concentrated sulfuric acid and has excellent chemical resistance (Japanese Patent Publication No. 47-617).

[Problem to be solved by the invention]

However, polyphenylene sulfide resin has a thermal deformation temperature of 130 to 140°C when used as a single resin, and has the disadvantage that the molded product is extremely brittle. By blending fillers in the form of fillers, improvements such as improvements in heat distortion temperature, mechanical strength, and reduction in linear expansion coefficient are achieved.

However, despite the improvement in strength and heat resistance with the above-mentioned filler, PoI7 phenylene sulfide resin causes the molded product to crack when immersed in a 260°C solder bath for 10 seconds after molding the electronic component. Otherwise, it has the disadvantage of generating cracks. For this reason, 260
Applications that require solder resistance above ℃, such as IC.

The capacitor is a single component and cannot be used as a surface mount type.

Furthermore, aromatic polythioetherketone alone has a large coefficient of linear expansion and a heat distortion temperature of 185° C., so it cannot be used in the field of electronic component sealing, which requires high heat resistance.

In view of the above situation, the inventors of the present invention set it as their object to obtain a thermoplastic resin composition for encapsulating electronic components that has solder resistance at 260° C. or higher and good fluidity.

[Means to solve the problem]

That is, the present invention comprises (a) 30 to 90% by weight of aromatic polythioether ketone resin, (b) siliceous filler 1
The object of the present invention is to provide a thermoplastic resin composition for encapsulating electronic components, comprising 0 to 60% by weight and (iii) 0 to 50% by weight of a fibrous filler.

The aromatic polythioetherketone resin (hereinafter abbreviated as PP5K) used in the present invention is a polymer having a structural formula.

Examples of polymerization methods for this polymer include, for example, a method in which a dihalogen aromatic ketone and an alkali metal sulfide are reacted in an organic amide solvent (Japanese Patent Publication No. 47-617), and an aromatic thioether and phosgene are reacted in the presence of a Lewis acid in the presence of a Lewis acid. Method of reaction in a protic organic solvent (JP-A-60-729
Publication No. 23). Furthermore, a copolymer or block copolymer of an aromatic thioetherketone polymer and a sulfide sulfone polymer can also be used without departing from the object of the present invention.

The molecular weight of PP5K used in the present invention is not particularly limited, but the logarithmic viscosity yinh (solvent = 98% concentrated sulfuric acid,
Polymer concentration: 0.5 f/dl, measurement temperature: 25° C.) is preferably in the range of 0.2 to 0.7.

In particular, when sealing elements having bonding wires such as ICs and transistors, those with low molecular weight are preferably used to avoid damage to the bonding wires.

The PP5K used in the present invention can be any PP as described above.
5K can also be used, but PP5K1 that has been subjected to (1) acid treatment, (2) hot water washing, or (3) organic solvent washing, or (4) PP with a sodium content of 900 or less.
It is preferable to use 5K because the effects of the present invention are further expressed.

These preferred PPSK treatments will be described below.

The case of acid treatment is as follows.

The acid treatment may be carried out by immersing PP5K in an acid or an aqueous solution of the acid, and stirring or heating may be carried out as necessary.

For example, when using acetic acid, a pH 4 aqueous solution of 80 to 9
A sufficient effect can be obtained by immersing the PP5K powder in a solution heated to 0° C. and stirring for 30 minutes. The acid-treated PP5K needs to be washed several times with water or hot water in order to physically remove residual acids or salts.

The water used for washing is preferably distilled water or deionized water in the sense that it does not impair the preferable chemical modification effect of PP5K by acid treatment.

When washing with hot water, the procedure is as follows. That is, when treating PP5K with hot water, the temperature of the hot water is set to 100°C or higher, more preferably 120°C or higher, and even more preferably 150°C.
As mentioned above, it is particularly important to set the temperature to 170°C or higher; a temperature lower than 100°C is not preferable because the effect of the preferred chemical modification of PP5K is small.

In order to achieve the desired effect of chemical modification of PP5K by hot water washing according to the present invention, the water used is preferably distilled water or deionized water. The hot water treatment is usually performed by adding a predetermined amount of PP5K to a predetermined amount of water, and heating and stirring the mixture in a pressure vessel. As for the ratio of PP5K to water, it is preferable that there is more water, but usually a bath ratio of 0 g or less of PPSK2O to 11 water is selected.

Furthermore, since decomposition of terminal groups is undesirable, the treatment atmosphere is preferably an inert atmosphere to avoid this. Furthermore, PP5K that has undergone this hot water treatment operation is
It is preferable to wash with warm water several times to physically remove any remaining components.

When washing with an organic solvent, the procedure is as follows.

The organic solvent used for washing PP5K is not particularly limited as long as it does not have the effect of decomposing PP5K, and examples include N-methylpyrrolidone, dimethylformamide, dimethylacetamide, 1,3-dimethylimidazolidinone, and hexamethyl. Nitrogen-containing polar solvents such as phosphorus amide and piperazinones, sulfoxide/sulfone solvents such as dimethyl sulfoxide, dimethyl sulfone, and sulfolane, ketone solvents such as acetonate, methyl ethyl ketone, diethyl ketone, and acetophenone, dimethyl ether, dipropyl ether, Ether FJ media such as dioxane and tetrahydrofuran, halogenated solvents such as chloroform, methylene chloride, trichloroethylene, ethylene dichloride, perchlorethylene, monochloroethane, dichloroethane, tetrachloroethane, perchloroethane, and chlorobenzene, methanol, ethanol, Examples include alcohol/phenol solvents such as propatool, butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, polyethylene glycol, and polypropylene glycol, and aromatic hydrocarbon solvents such as benzene, toluene, and xylene. Among these organic solvents, N-methylpyrrolidone, acetone,
Particularly preferred is the use of dimethylformamide, chloroform and the like. Further, these organic solvents may be used alone or in combination of two or more.

As a method of cleaning with an organic solvent, PP is added in an organic solvent.
There are methods such as immersing 5K, and it is also possible to stir or heat as necessary.

There is no particular restriction on the cleaning temperature when cleaning PP5K with an organic solvent, and any temperature from room temperature to about 300°C can be selected. Although there is a tendency that the higher the cleaning temperature, the higher the cleaning efficiency, a sufficient effect can usually be obtained at a cleaning temperature of room temperature to 150°C.

It is also possible to wash under pressure in a pressure vessel at a temperature above the boiling point of the organic solvent. Furthermore, there is no particular restriction on the cleaning time. Although it depends on the cleaning conditions, in the case of batch cleaning, sufficient effects can usually be obtained by cleaning for 5 minutes or more.

It is also possible to wash continuously.

Although it is sufficient to simply wash the PP5K produced by polymerization with an organic solvent, in order to further exhibit the effects of the present invention, it is preferable to combine washing with water or hot water.

Further, when a high-boiling water-soluble organic solvent such as N-methylpyrrolidone is used, the residual organic solvent can be easily removed by washing with water or hot water after washing with the organic solvent. The water used for these washings is preferably distilled water or deionized water.

Further, in order to fully exhibit the effects of the present invention, the PP5K used in the present invention preferably has a sodium content of 900P or less. As an effective means for reducing the sodium content of PP5K having a sodium content of 900P or more to 900P or less, treatments such as the above-mentioned acid treatment, hot water treatment, or washing with an organic solvent can be used.

Acid treatment, hot water treatment and washing with an organic solvent of PP5K described above, and P with a sodium content of 900- or less
P5K is only preferable in order to further express the effects of the present invention, and is by no means an essential condition for the present invention. Any PP5K can be used in the present invention.

The blending ratio of such PP5K in the composition is 30 to 9
0% by weight, preferably 40 to 70% by weight. If it is less than 30% by weight, the fluidity during sealing molding will deteriorate, so it is not suitable. Moreover, if it exceeds 90% by weight, the filler content becomes too small and the linear expansion coefficient of the encapsulated molded product increases, which is not preferable.

The siliceous filler used in the present invention is a non-fibrous inorganic filler mainly composed of silica, and includes quartz, talc, kaolin, etc., preferably quartz, more preferably 99% or more Examples include commercially available fused silica, crystalline silica, pulverized synthetic silica, and spherical silica with purity. The proportion of the siliceous filler in the entire composition of the present invention is 60 to 10% by weight, preferably 50 to 15% by weight.
A weight percent range is selected. If it is less than 10% by weight, the effect of improving the linear expansion coefficient decrease is insufficient, and if it exceeds 60% by weight, fluidity deteriorates, which is not preferable.

Two or more of these siliceous fillers can be used in combination, and if necessary, they can be pretreated with a silane-based and titanium-based coupling agent before use.

The fibrous fillers used in the present invention include glass fibers, ceramic fibers, asbestos, potassium titanate fibers, other inorganic fibers, carbon fibers, polyamides, polyesters,
Other organic synthetic fibers are suitable, of which glass fibers are particularly preferred. The amount of such fibrous filler in the composition is 0 to 50% by weight, preferably 5 to 30% by weight.
A weight percent range is selected. If it exceeds 50% by weight, fluidity during sealing molding will deteriorate. In addition, the fiber length of the fibrous filler is determined to be 0.03 after extrusion kneading in terms of mechanical strength of the composition and fluidity during sealing molding.
It is preferable that it is ff~1, Ou.

The composition of the present invention includes antioxidants, heat stabilizers, lubricants, colorants, ultraviolet absorbers, and
Other types of polymers can be added and blended.

The method for preparing the composition of the present invention is not particularly limited, and a boat fishing method may be used. For example, each component is mixed together at room temperature using a ribbon blade type mixer or a drum type rotating mixer, and then melted and mixed using a single screw extruder, multi-screw extruder, or kneader, and then pelletized. .

〔Example〕

The present invention will be explained in more detail by showing Examples and Comparative Examples below. Note that all parts and percentages shown in the examples are based on weight.

Reference Example 1 (Polymerization of PPSK) 30% sodium bisulfide aqueous solution H9,3 in an autoclave
4kqc sodium hydrosulfide 50 moles), 50% sodium hydroxide 4.00 &g (sodium hydroxide 50 moles)
and 16 # of N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) were charged, and the temperature was gradually raised to 205° C. while stirring, and 8.01 of distilled water containing 7.5 and 9 of water was removed. Bis(p-chlorophenyl)ketone 12 is added to the residual mixture.
．． Add 55 kq and NMP4, pressure 3.2 ky
/d gauge pressure at 250°C for 5 hours.

The reaction product was washed twice with ion-exchanged water and five times with ion-exchanged hot water at 70°C, and then dried under reduced pressure at 120°C for 24 hours to obtain a PP5K resin powder of about 4.5#.

The obtained PP5K had a logarithmic viscosity of 0.40, a glass transition temperature of 145°C, and a melting point of 348°C.

[Reference Example 2] 2 kq of PP5K powder obtained in Reference Example 1 was put into 201 aqueous acetic acid solution of pH 4 heated to 90°C, and about 30
After continuing to stir for a minute, it was filtered, washed with deionized water at about 90°C until the pH of the P solution became 7, and dried under reduced pressure at 120°C for 24 hours to form a powder, which was used in Examples. This PP
The total sodium content in 5K was 375F.

Examples 1 to 4, Comparative Examples 1 to 2 After tri-blending the PP SK powder, silicic acid filler, and fibrous filler obtained in Reference Example 2 with the composition shown in Table 1, the mixture was fed to a 30rj0 twin-screw extruder. The processing temperature is 350~
The mixture was melt-kneaded at 380°C to obtain homogeneous melt-blended pellets. Subsequently, the obtained pellets were placed in an injection molding machine (temperature 360
A test piece was molded at a temperature of ~380°C and a mold temperature of 170°C, and the physical properties were measured to obtain the results shown in Table 1.

In addition, insert-only injection molding machines (temperature 360-380
A 16-pin DIP type IC sealed product was molded at a mold temperature of 200°C, and the presence of blisters and cracks in the sealed product was determined by soft Observed by law.

The results were as shown in Table 1.

As is clear from the results in Table 1, it can be seen that the composition of this example has excellent solder resistance.

Comparative Example 3 A test piece and a DIP type IC seal were prepared in the same manner as in Example 1, using polyphenylene sulfide resin 1 Ryton V-1' (manufactured by Philips) instead of PP5K used in Example 1. A fixed product was molded and evaluated. The results were as shown in Table 1.

〔Effect of the invention〕

Since the thermoplastic resin composition for encapsulating electronic components of the present invention has excellent solder resistance and fluidity, it is very useful as a material for encapsulating electronic components such as ICs, Lansyster diodes, capacitor connectors, etc. be.

Patent applicant Higashi Shikikai Co., Ltd.

Claims (1)

[Scope of Claims] (a) 30 to 90% by weight of aromatic polythioetherketone resin, (b) 10 to 60% by weight of siliceous filler, and (c)
A thermoplastic resin composition for encapsulating electronic components comprising 0 to 50% by weight of a fibrous filler.