JPH0782462A - Epoxy resin master batch for sealant and its production - Google Patents

Abstract

PURPOSE:To provide an epoxy resin master batch used for sealants and capable of improving the strengths of formed resin molded products without deteriorating the good flowability of a spherical silica-filled epoxy resin, and a method for producing the same. CONSTITUTION:A fine powdery epoxy resin master batch for sealants contain fine silica short fibers having a diameter of <=10mum and an aspect ratio of at least 5 in an amount of 10-20wt.% based on the whole amount of an epoxy resin composition not compounded with a spherical silica filler. The master hatch is produced by adding 10-20wt.% of silica fibers to the epoxy resin not compounded with the spherical silica filler, sufficiently kneading the mixture, solidifying the kneaded product and subsequently grinding the solidified product into the ground product having particle sizes of <=150 mesh.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a masterbatch (compounding precursor) useful as a constituent material of an epoxy resin composition for an IC encapsulant containing spherical silica as a filler, and a method for producing the same.

[0002]

2. Description of the Related Art A large amount of silica filler (70-80%) is used in epoxy resin compositions for semiconductor encapsulants such as IC packages.
%), But recently, the amount of spherical silica used as this silica filler is increasing. The reason for this is
Spherical silica is superior in fluidity to crushed silica and can be highly filled, mold wear is lower than crushed silica, and stress concentration point because there is no corner like crushed silica This is due to the property characteristics such as the occurrence of no damage and the possibility of damaging the surface of the IC chip. However, on the other hand, when spherical silica is filled, the mechanical strength of the resin molded body is lowered.

As a method for improving the mechanical strength of spherical silica, an attempt has been made to make the surface of spherical silica uneven, as described in, for example, Japanese Patent Application Laid-Open No. 3-257090, but the surface of the spherical silica is Since it is difficult to form the unevenness having a sufficient depth, a great effect cannot be expected. Moreover, in the case of spherical particles having a relatively large particle size (10 μm or more), there is a problem that the spherical particles are destroyed in the process of making unevenness on the surface, so that they have not been put into practical use.

[0004]

Therefore, at present, a measure is taken in which crushed silica is mixed and used while sacrificing the fluidity peculiar to spherical silica.

In view of the above situation, the inventors of the present invention have made extensive studies as to measures for improving the mechanical strength of a resin composition when spherical silica is filled, and as a result, the epoxy resin component before the spherical silica is filled with a specific property. By preparing a masterbatch fine powder in which a fixed amount of silica short fiber of is prepared, the mechanical strength of the resin molded body filled with spherical silica is improved,
Moreover, it was confirmed that the mixing of the masterbatch and the spherical silica proceeded extremely smoothly.

The present invention has been developed on the basis of the above findings, and an object thereof is to improve the mechanical strength of a resin molded body to be formed without impairing the fluidity at the time of filling spherical silica. An object of the present invention is to provide a spherical silica-filled epoxy resin masterbatch for encapsulant and a method for producing the same.

[0007]

The epoxy resin masterbatch for encapsulant according to the present invention for achieving the above object has a diameter of 10 μm or less and an aspect ratio of at least 5.
In the constitution, the short silica fiber having the fine properties of 10 to 20% by weight is contained in the range of 10 to 20% by weight with respect to the total amount of the epoxy resin composition for encapsulant containing no spherical silica filler. It is a feature of.

The epoxy resin masterbatch for encapsulant according to the present invention (hereinafter, simply referred to as "masterbatch") is a silica filler among epoxy resin compositions for encapsulant having a conventionally known composition. Consists of fine powder in which silica short fibers with specific properties are mixed and dispersed in components that do not contain,
It is a precursor component to be blended with the spherical silica filler in the subsequent step.

The silica short fibers contained in the masterbatch have a diameter of 10 μm or less and an aspect ratio of at least 5.
It is necessary to have the fine characteristics of. With silica short fibers that deviate from this property range, improvement in material strength cannot be expected when a resin molded body is formed. If the length of the silica short fibers exceeds about 100 μm, it becomes difficult to uniformly disperse them in the resin component, and the gate of the mold may be closed during molding. Therefore, the length of the silica short fibers is preferably about 100 μm or less in the range where the aspect ratio does not fall below 5. Needless to say, the silica short fibers contained must have high purity, and impurities such as uranium and thorium that emit α-radiation are removed as much as possible before use.

The masterbatch contains short silica fibers in an amount of 10 to 20% by weight based on the total amount of epoxy resin and other components. If the content is less than 10% by weight, it does not contribute to the improvement of the strength of the molded resin body, and if it exceeds 20% by weight, the crushing process during the production of the masterbatch becomes difficult. The particle size of the fine powder of the masterbatch is preferably 150 mesh or less from the viewpoint of easy mixing with the spherical silica filler.

The production method of the present invention for obtaining the above-mentioned masterbatch is 10 to 20% by weight based on the total amount of the epoxy resin composition for encapsulant containing no spherical silica filler.
After mixing the silica fiber of, kneading thoroughly and solidifying,
It is characterized in that it is pulverized to a particle size of 150 mesh or less.

The epoxy resin composition for encapsulant containing no spherical silica filler is a component mainly containing an epoxy resin, a curing agent, a curing accelerator, a release agent, a colorant, a flame retardant, a surface treatment agent and the like. Is. High-purity silica fiber cut to an appropriate length is added to the total amount of these components in the range of 10 to 20% by weight. Silica fiber content is 10% by weight
If it is less than 20% by weight, the material strength of the resin molded product is not improved, and if it exceeds 20% by weight, the hardness of the cured product becomes too high and the pulverization process becomes difficult.

The compound of the epoxy resin composition of the encapsulating material and the silica fiber is kneaded by using a kneading device such as a hot roll or a kneading machine until the silica fiber is sufficiently homogeneously dispersed, and then the resin component is cooled and solidified. . Subsequently, the solidified product is ground until the particle size becomes 150 mesh or less. Through this kneading and crushing process, the silica fibers are crushed and become fine short fibers having a diameter of 10 μm or less and an aspect ratio of 5 to 100 and are compounded in the resin component.

The masterbatch produced in the above process is blended with a spherical silica filler and uniformly kneaded.
The encapsulant resin compound is obtained by cooling, crushing and tableting. The mixing ratio of the masterbatch and the spherical silica filler is set based on the relationship such as the fluidity in the molding die and the molding strength of the obtained resin compound, but the ratio of silica short fibers to the total amount of silica is generally 1 to 5% by weight. The range of% is preferred.

[0015]

The epoxy resin masterbatch for encapsulant according to the present invention is a composite fine powder in which fine silica short fibers are uniformly dispersed in the resin composition. Therefore, when the spherical silica filler is kneaded to this, since the silica short fibers contained in the master batch function as a fiber reinforcing material, the final product is obtained while maintaining the good flowability of the spherical silica. The effect of improving the material strength of the resin molded body is brought about.

On the other hand, in the production method of the present invention, a step of blending a predetermined amount of silica fibers cut to an appropriate length with an epoxy resin component containing no spherical silica filler, kneading, solidifying and crushing is required. However, the reason for this is based on the following technical basis. Silica fiber has a very bulky fluffy appearance with an apparent specific gravity of 0.1 g / cc or less, so even if you try to mix it directly with spherical silica, a uniform mixed state cannot be obtained, and It is extremely difficult to finely grind silica fibers as they are. However, once this is kneaded and dispersed in the resin, the solidified product is finely pulverized to a particle size of 150 mesh or less,
Through the crushing process, the short silica fibers are crushed and become finely dispersed fine particles, which facilitates homogeneous mixing with the spherical silica filler. Due to this action, it becomes possible to obtain the encapsulant compound having excellent fluidity and molding strength.

[0017]

EXAMPLES Examples of the present invention will be specifically described below in comparison with comparative examples.

Examples 1-6, Comparative Examples 1-2 (1) Preparation of epoxy resin masterbatch: Biphenyl type epoxy resin ("Epicoat YX4000H") 100 parts by weight, novolac type phenolic resin curing agent ("Barkham TD"
2131 ") 54 parts by weight, triphenylphosphine 2 parts by weight, OP-wax 1 part by weight and carbon black 1
Silica fibers (manufactured by Toshiba Ceramics Co., Ltd.) were compounded in an epoxy resin composition consisting of parts by weight at a ratio of 10% by weight based on the total amount. Silica fiber has a diameter of 5μ
m chopped fiber (silica fiber A), and diameter 10
It was a chopped fiber (silica fiber B) of μm. The mixture was passed through a hot roll and kneaded at 80 ° C. for 7 minutes, then peeled from the roll and cooled and solidified. Then, the solidified product was mechanically pulverized to a particle size of 150 mesh (105 μm) or less to produce a masterbatch (MB-1). When the silica fiber contained in the obtained masterbatch fine powder was observed, it was confirmed that it was converted into fine short fibers crushed to a length of about 50 to 100 μm. For comparison, an epoxy resin composition (MB-2) containing no silica short fibers was also tested.

(2) Evaluation of fluidity: Spherical silica filler having an average particle diameter of 22 μm (manufactured by Nippon Kagaku Kogyo KK, “Sylstar M2430”) or crushed silica filler having an average particle diameter of 12 μm (manufactured by Tatsumori Co., Ltd., VLM64] was blended with the above masterbatch in the formulation (parts by weight) shown in Table 1 and kneaded with a hot roll (85 ° C., 7 minutes), followed by cooling and solidification to pulverize a solidified product. For the obtained resin compound powder (average particle diameter 55 μm), spiral flow (SiO ₂ : 82%) was measured according to EMMI 1-66.

[0020]

[Table 1]

From the results shown in Table 1, the resin compounds according to the examples showed the same fluidity as that of the spherical silica product, although the short silica fibers were contained therein.

(3) Evaluation of strength characteristics: Using the resin compound of each example evaluated for fluidity, a test piece (10 × 100 × 4 mm) was molded using a mold for strength measurement. The molded body was cured at a temperature of 180 ° C. for 5 hours to prepare a strength measurement sample. With respect to this sample, the strength and elastic modulus at high temperature and the strength and elastic modulus at high temperature after absorbing water were measured. The strength is measured by the three-point bending strength measurement method using an autograph. The high temperature strength is the strength when the test piece is held for 3 minutes in an atmosphere of 220 ° C, and the high temperature strength after water absorption is 121 ° C by PCT for a time. After water absorption treatment was carried out under the condition of 24 hours, the strength when held in an atmosphere of 220 ° C. for 3 minutes was measured. The results are shown in Table 2.

[0023]

[Table 2]

From the results shown in Table 2, the strength characteristics of the molded articles according to the examples are improved as compared with the case of using spherical silica alone, and in particular, the silica short fiber content in the resin compound is 1.
It is recognized that if it exceeds%, a good effect is exhibited.

Comparative Example 3 In the masterbatch composition of Example 1, the silica short fiber A content was changed to 25% by weight, and the mixture was kneaded with a hot roll and solidified by cooling. This solidified material was crushed, but
It could not be ground to a particle size of 0 mesh or less.

Comparative Examples 4 to 8 The same epoxy resin composition (MB-2) containing no silica fiber as in Example 1 was used and blended with the silica filler or silica fiber A in the formulation shown in Table 3. However, in this example, the silica filler or silica short fibers were directly kneaded in the process of kneading the epoxy resin composition with a hot roll. Then,
After cooling and solidification, it was pulverized to prepare a granular resin compound of about 1 mm, and the spiral flow and high temperature strength were measured. The results are shown in Table 4.

[0027]

[Table 3]

[0028]

[Table 4]

From the results shown in Tables 3 and 4, when silica fibers are directly kneaded on a hot roll, it becomes difficult to uniformly disperse the silica fibers. Therefore, even if the content of silica fibers is increased, no improvement in strength characteristics is observed. .

[0030]

As described above, by using the epoxy resin masterbatch for encapsulant according to the present invention, it is possible to uniformly mix spherical silica and to mold without substantially impairing the fluidity of the resin compound. It is possible to improve body strength. Therefore, superior performance is imparted as compared with the conventional resin compound in which spherical silica and crushed silica are blended. Further, according to the production method of the present invention, silica fibers can be easily mixed in the encapsulant epoxy resin composition, and it becomes possible to industrially produce a functional encapsulant resin compound. .

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H01B 3/40 N 9059-5G H01L 23/29 23/31

Claims (2)

[Claims] 1. Silica short fibers having a diameter of 10 μm or less and an aspect ratio of at least 5 and having a fineness of 10 to 20% by weight with respect to the total amount of the epoxy resin composition for encapsulant containing no spherical silica filler. % Master powder epoxy resin masterbatch for encapsulants. 2. 10 to 20% by weight based on the total amount of the epoxy resin composition for encapsulants, which does not contain a spherical silica filler.
After mixing the silica fiber of, kneading thoroughly and solidifying,
A method for producing an epoxy resin masterbatch for a sealing material, which comprises pulverizing to a particle size of 150 mesh or less.