JP2006117881A - Additive for epoxy resin, its composition and its use - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an additive for an epoxy resin capable of upgrading flame resistance and adhesiveness to a metal by adding to an epoxy resin composition consisting of the epoxy resin and a phenolic resin hardener for use in the semiconductor sealing field. <P>SOLUTION: The additive for a epoxy resin comprises an aromatic sulfur compound having two or more thiol groups or mercaptomethyl groups etc. directly linking to an aromatic ring. The epoxy resin composition comprising the additive for a epoxy resin, a epoxy resin and a phenolic resin hardener is provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an additive for an epoxy resin, which acts as a curing agent for the epoxy resin, and can improve the flame retardancy and adhesion to metal of the epoxy resin, its composition, and its use.

  Epoxy resins are used in a wide range of fields such as electrical and electronic insulating materials, civil engineering / building materials, adhesives, and paints because of their excellent properties. As the curing agent for the epoxy resin, amines, acid anhydrides, polyamides, imidazoles, phenol resins, polymercaptans (see Patent Documents 1 to 3) and the like are properly used according to such applications.

  In the field of insulating materials for electrical and electronic applications, epoxy resins are used as various binders and coating agents for wiring boards, semiconductor encapsulants, etc. From the viewpoint of reducing halogens derived from flame retardants, the emergence of highly flame retardant resins and halogen-free additives is strongly desired. For example, as a semiconductor sealing method, an epoxy resin such as an ortho-cresol novolac type epoxy resin, a resin sealing composed of a phenol resin such as a phenol novolac resin and an inorganic filler such as silica as a curing agent is widely used. Conventionally, brominated epoxy resins and antimony compounds have been used in combination for imparting flame retardancy. However, the use restriction requirement for brominated flame retardants that are suspected of producing dioxins during combustion and antimony compounds that are suspected of causing carcinogenicity has been strengthened, and there has been a demand for non-halogenated formulations that achieve the desired flame retardant without using them. .

  For these problems, (1) increase in the amount of inorganic filler to be blended, high filling, (2) application of an alternative flame retardant, (3) flame retardancy of an epoxy resin or a curing agent, and the like have been attempted. Of these, the formulation (1) cannot exhibit satisfactory performance in terms of fluidity and moldability. In the formula (2), as alternative flame retardants, attempts have been made to use phosphorus compounds such as phosphate esters and metal hydroxides such as magnesium hydroxide. However, satisfactory performance is not always obtained. Furthermore, in the formulation of (3), in order to make the resin itself flame-retardant, highly aromatic epoxy resins and curing agents are used for some sealants, but moldability, fluidity, heat resistance In terms of performance and economy, it is still not enough.

  Epoxy resins for semiconductor encapsulant applications have also been required to improve adhesiveness, heat resistance, moisture resistance, etc., as the solder is lead-free.

Japanese Patent Publication No. 47-32319 JP-A-55-102624 JP 61-162517 A

  In view of the above situation, the present inventors have examined non-halogen flame retardants for epoxy resins that can be used as semiconductor sealing materials. At the same time, an additive for improving the adhesion to metal was examined. As a result, specific aromatic sulfur compounds different from those proposed in the past improve flame retardancy and adhesion to metals without substantially sacrificing moldability or heat resistance of the epoxy resin. And reached the present invention. Accordingly, the object of the present invention is to improve the flame retardancy of epoxy resin, the additive for epoxy resin useful for improving the metal adhesiveness, etc. The object is to provide an epoxy resin composition.

（式中、ｎは０又は１以上の整数、Ｒは水素又はメチル基であり、２ｎ個のＲは同一であっても異なっていてもよい） That is, according to this invention, the additive for epoxy resins which consists of an aromatic sulfur compound which has 2 or more of functional groups shown by following General formula (1) directly connected to an aromatic ring is provided.

(Wherein n is 0 or an integer of 1 or more, R is hydrogen or a methyl group, and 2n Rs may be the same or different)

（式中、ｎは０又は１以上の整数、ｍは１以上の整数、Ｒは水素又はメチル基であり、それぞれ同一であっても異なっていてもよい。Ｘは、直接結合、アルキレン基、Ｓ又はＯである。） One example of a suitable aromatic sulfur compound is a sulfur compound represented by the following formula (2).

(In the formula, n is 0 or an integer of 1 or more, m is an integer of 1 or more, R is hydrogen or a methyl group, which may be the same or different. X is a direct bond, an alkylene group, S or O.)

One example of a suitable aromatic sulfur compound represented by the general formula (2) is a sulfur compound represented by the following formula (3).

Another example of a suitable aromatic sulfur compound represented by the general formula (2) is a sulfur compound represented by the following formula (4).

（式中、Ｒは水素又はメチル基である。） Another preferred example of the aromatic sulfur compound having two or more functional groups represented by the general formula (1) is a sulfur compound represented by the following general formula (5).

(In the formula, R is hydrogen or a methyl group.)

  According to this invention, the epoxy resin composition formed by mix | blending the additive which consists of the said aromatic sulfur compound with an epoxy resin is also provided. Such an epoxy resin composition preferably further contains a phenol resin-based curing agent, and preferably contains an inorganic filler. Such an epoxy resin composition is preferably used for semiconductor encapsulation.

  ADVANTAGE OF THE INVENTION According to this invention, the additive for epoxy resins which can improve a flame retardance and the adhesiveness with respect to a metal can be provided. Epoxy resin compositions containing such additives are excellent in processability, heat resistance, moisture resistance, flame retardancy, adhesiveness, etc., and are used for molding materials, various binders, coating materials, laminated materials, etc. be able to. In particular, a semiconductor device that is useful for semiconductor sealing and excellent in heat resistance, moisture resistance, flame retardancy, adhesiveness, and the like can be manufactured.

式中、ｎは０又は１以上の整数、例えば５以下の整数、好ましく０又は１である。Ｒは水素又はメチル基であり、２ｎ個のＲは同一であっても異なっていてもよい。Ｒは、好ましくは全て水素である。 The additive for epoxy resin of the present invention is an aromatic sulfur compound having 2 or more, preferably 2 to 4 and particularly preferably 2 to 3 functional groups represented by the general formula (1) directly connected to the aromatic ring. is there.

In the formula, n is 0 or an integer of 1 or more, for example, an integer of 5 or less, preferably 0 or 1. R is hydrogen or a methyl group, and 2n R may be the same or different. R is preferably all hydrogen.

An example of the aromatic sulfur compound is a sulfur compound represented by the following general formula (2).

  In the above formula, n is 0 or an integer of 1 or more, for example, an integer of 5 or less, preferably 0 or 1. R is hydrogen or a methyl group, and all R may be the same or different. R is preferably all hydrogen. M is an integer of 1 or more, preferably 1 to 10, particularly preferably 1 to 5.

Preferable examples of the compound represented by the above formula (2) include a compound represented by the following formula (3).

In the above formula (3), four Rs are selected from hydrogen or a methyl group, but are preferably compounds in which all are hydrogen. X is a direct bond, an alkylene group, for example, a group such as methylene, ethylidene or isopropylidene, S or O. In the above formula, the position of the CR ₂ SH group is arbitrary, and for example, isomers such as 2,2′-, 2,4′-, and 4,4′- can be used. A sulfur compound represented by the following formula (6) which is a '-isomer is preferable.

More specifically, as a compound represented by the above formula (6), R is all hydrogen and X is a direct bond, a compound represented by the following formula (7), or R is all H and X is A methylene group, a compound which is S or O, etc. can be illustrated.

As another example of the aromatic sulfur compound represented by the general formula (2), a sulfur compound represented by the following general formula (4) can be exemplified.

In the above formula (4), X is a direct bond, an alkylene group, for example, a group such as methylene, ethylidene, isopropylidene, S or O. In the above formula, the position of the SH group is arbitrary, and for example, isomers such as 2,2′-, 2,4′-, and 4,4′- can be used. Sulfur compounds represented by the following formula (8) which are isomers are preferred.

As another example of the aromatic sulfur compound having two or more functional groups represented by the general formula (1) directly connected to the aromatic ring, a sulfur compound represented by the following general formula (5) can be exemplified.

In the above formula, four Rs are selected from hydrogen or a methyl group, but are preferably compounds in which all are hydrogen. Moreover, as said compound, although each isomer of o-, m-, or p- can be used, use of the p-isomer shown by following formula (9) is especially preferable.

  The aromatic sulfur compound as described above is useful as an additive for an epoxy resin, and particularly when used in combination with a phenol resin-based curing agent, can form an epoxy resin composition having desirable properties as a semiconductor sealing material. it can.

  Examples of the epoxy resin used for blending the aromatic sulfur compound of the present invention include, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, cresol novolac type epoxy resin, phenol novolac type epoxy resin, and biphenyl type epoxy resin. , Phenol biphenyl aralkyl type epoxy resin, epoxidized aralkyl resin by xylylene bond such as phenol, naphthol, glycidyl ether type epoxy resin such as dicyclopentadiene type epoxy resin, dihydroxynaphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine An epoxy resin having two or more epoxy groups in the molecule, such as a type epoxy resin. These epoxy resins may be used alone or in combination of two or more.

  In blending the aromatic sulfur compound of the present invention with an epoxy resin, it is preferable to use a phenol resin curing agent in combination. Examples of such a phenol resin-based curing agent include compounds having two or more phenolic hydroxyl groups in one molecule, such as a phenol novolak resin, a cresol novolak resin, a phenol aralkyl resin, a phenol naphthyl aralkyl resin, and a phenol biphenyl aralkyl. Examples thereof include a resin, a naphthol aralkyl resin, a triphenolmethane type novolak resin, and a dicyclopentadiene type phenol resin.

  When using the epoxy resin composition which mix | blended the said aromatic sulfur compound or the phenol resin type hardening | curing agent with the epoxy resin for semiconductor sealing, addition of an inorganic filler is essential. Examples of such inorganic fillers include amorphous silica, crystalline silica, alumina, glass, calcium silicate, gypsum, calcium carbonate, magnesite, clay, talc, mica, magnesia, barium sulfate and the like. However, amorphous silica, crystalline silica and the like are particularly preferable. In order to increase the blending amount of the filler while maintaining excellent moldability, it is preferable to use a spherical filler having a wide particle size distribution that enables fine packing.

  If necessary, the epoxy resin composition may contain other additives such as curing accelerators, coupling agents, mold release agents, colorants, other flame retardants, flame retardant aids, and low stress agents. Can do.

  As the curing accelerator, a known curing accelerator for curing an epoxy resin with a phenol resin curing agent can be used. For example, a tertiary amine, a quaternary ammonium salt, an imidazole, an organic phosphine compound, A quaternary phosphonium salt can be mentioned. More specifically, tertiary amines such as triethylamine, triethylenediamine, benzyldimethylamine, 2,4,6-tris (dimethylaminomethyl) phenol, 1,8-diazabicyclo (5,4,0) undecene-7, Imidazoles such as imidazole, 2-methylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, triphenylphosphine, tributylphosphine, tri ( Examples thereof include organic phosphine compounds such as p-methylphenyl) phosphine and tri (nonylphenyl) phosphine, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetranaphthoic acid borate and the like.

  Examples of coupling agents include silane coupling agents such as vinyl silane, amino silane, and epoxy silane, and titanium coupling agents. Examples of mold release agents include carnauba wax, paraffin wax, stearic acid, and montanic acid. Examples of the carboxyl group-containing polyolefin wax and the colorant include carbon black. Examples of the flame retardant include halogenated epoxy resins, halogen compounds, and phosphorus compounds, and examples of the flame retardant aid include antimony trioxide. Examples of the low stress agent include silicon rubber, modified nitrile rubber, modified butadiene rubber, and modified silicone oil.

  In the epoxy resin composition, when the aromatic sulfur compound and the phenol resin curing agent are blended with the epoxy resin, in consideration of moldability and the properties of the cured resin, (mercapto group + phenolic hydroxyl group) / epoxy group The equivalent ratio is preferably in the range of 0.5 to 1.5, particularly 0.8 to 1.2. In consideration of moldability, moisture resistance, heat resistance, flame retardancy, adhesion, etc., the use ratio of the aromatic sulfur compound and the phenol resin curing agent is 1/99 to the equivalent ratio of mercapto group / phenolic hydroxyl group. 40/60, preferably 5/95 to 35/65, particularly preferably 10/90 to 30/70. It is effective to add about 0.1 to 5 parts by weight of the curing accelerator to 100 parts by weight of the epoxy resin. Further, when used as a semiconductor sealing material, the inorganic filler is preferably blended in such a proportion that it occupies 60 to 93% by weight of the entire composition, although it varies depending on the type.

  As a general method for preparing an epoxy resin as a molding material, a predetermined ratio of each raw material is sufficiently mixed by, for example, a mixer, kneaded by a hot roll or a kneader, and then cooled and solidified. The method of crushing to a suitable size can be mentioned. The molding material thus obtained can be used to manufacture a semiconductor device by sealing the semiconductor element by, for example, low-pressure transfer molding. Curing of the epoxy resin composition can be performed, for example, in a temperature range of 100 to 250 ° C.

  Hereinafter, the present invention will be described in more detail with reference to examples.

[Reference Example 1]
A four-necked flask was charged with 125.5 g (0.50 mol) of 4,4′-bischlorobiphenyl (Aldrich reagent purified product) and 753 g of 1,4-dioxane and heated to 55 ° C. while stirring. Then, a solution composed of 83.6 g (1.10 mol) of thiourea and 250.8 g of ethylene glycol was added dropwise over 30 minutes. After dropping, the temperature was raised to 95 ° C. and held for 30 minutes. Thereafter, 189.0 g (1.00 mol) of tetraethylenepentamine was added dropwise over 30 minutes, and the mixture was maintained at 95 ° C. for 30 minutes after completion of the addition.

  After completion of the reaction, the lower layer was removed by liquid separation, and 3000 g of pure water was added to the upper layer for crystallization. The crystals were separated from the suspension in which the crystals were precipitated by filtration, and rinsed five times with 1000 g of pure water. The obtained cake was vacuum-dried at 120 ° C. for 4 hours to obtain 113.4 g of 4,4′-bismercaptomethylbiphenyl represented by the formula (7).

In addition, 4,4'-bismercaptomethylbiphenyl was identified by ¹ H-NMR measurement. That is, 10 mg of a sample was dissolved in about 0.6 mL of THF- _ds (manufactured by Wako Pure Chemical Industries, Ltd., purity 100%), and ¹ H-NMR measurement was performed under the following conditions.
<Measurement conditions>
Device: JNM-ECA400
Resonance frequency: 400 MHz ( ¹ H-NMR)
Dissolving solvent: THF- _ds
Internal reference material: THF- _ds (1.73 ppm)
Integration count: 16 times

The measurement results are shown in Table 1 and FIG. These results support the chemical structure described in FIG.

[Example 1]
Epoxy resin (NC-3000P manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl type, epoxy equivalent 272 g / eq), phenol biphenyl aralkyl resin (HE200C-10 manufactured by Air Water Chemical Co., hydroxyl equivalent 204 g / eq), The ratio shown in Table 2 for 4,4'-bismercaptomethylbiphenyl (additive-1) obtained in Reference Example 1, fused silica and phosphorus-based curing accelerator (2- (triphenylphosphonio) phenolate, the same applies hereinafter) After mixing and mixing well, the mixture was kneaded with two rolls at 85 ° C. ± 3 ° C. for 3 minutes, cooled and ground to obtain an epoxy resin composition.

The epoxy resin composition was molded at 175 ° C. for 5 minutes at a pressure of 100 kgf / cm ² using a transfer molding machine, and then post-cured at 180 ° C. for 6 hours to obtain test pieces for measurement of flame retardancy and thermal elastic modulus. It was.

  The properties of these cured epoxy resins were measured by the following method, and the results are also shown in Table 2.

(1) Flame retardancy (UL94)
Flame retardance was evaluated according to the method of the UL-94 standard using a sample shape 120 × 13 × 1.6 mm strip. Moreover, when the afterflame time after 10 second combustion was set to t1, and the afterflame time after 10-second combustion after extinction was set to t2, it evaluated by the following.
F _max : Maximum value of t1 or t2 _Ftotal : _Total of t1 and t2 of 5 samples

(2) Elastic modulus at heat Measured according to JIS K6911 (sample shape: 80 × 10 × 4 mm strip, measured for flexural modulus after standing in a 260 ° C. atmosphere for 10 minutes).

(3) an adhesive force transfer molding machine, Ni-Pd-Au 175 ℃ at a pressure 100 kgf / cm ² the epoxy resin composition on the plated metal plate is, after forming 5 minutes, molded articles (2 mm × 2 mm × 2m), and the shear adhesive strength with the metal plate was measured at room temperature.

[Example 2]
Epoxy resin (Japan Epoxy Resin Co., Ltd. YX-4000H, biphenol type, epoxy equivalent 190 g / eq), phenol aralkyl resin (Air Water Chemical Co., Ltd. HE100C-15, hydroxyl group equivalent 175 g / eq), Reference Example The same procedure as in Example 1 was conducted except that 4,4′-bismercaptomethylbiphenyl obtained in 1 (additive-1), fused silica and phosphorus curing accelerator were blended in the proportions shown in Table 2. Thus, an epoxy resin composition was obtained and evaluated. The results are also shown in Table 2.

[Example 3]
Epoxy resin (NC-3000P manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl type, epoxy equivalent 272 g / eq), phenol biphenyl aralkyl resin (HE200C-10 manufactured by Air Water Chemical Co., hydroxyl equivalent 204 g / eq), Example 1 except that 1,4-bismercaptomethylbenzene (reagent product manufactured by Aldrich Co., Ltd., additive-2), fused silica, and phosphorus-based curing accelerator were blended in the proportions shown in Table 2. In the same manner as above, an epoxy resin composition was obtained and evaluated. The results are also shown in Table 2.

[Example 4]
Epoxy resin (NC-3000P manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl type, epoxy equivalent 272 g / eq), phenol biphenyl aralkyl resin (HE200C-10 manufactured by Air Water Chemical Co., hydroxyl equivalent 204 g / eq), Except for using bis (4-mercaptophenyl) sulfide (manufactured by Sumitomo Seika Co., Ltd., additive-3), fused silica and phosphorus curing accelerator in the proportions shown in Table 2, In the same manner as in Example 1, an epoxy resin composition was obtained and evaluated. The results are also shown in Table 2.

[Example 5]
Epoxy resin (EPKA-501H manufactured by Nippon Kayaku Co., Ltd., triphenolmethane type, epoxy equivalent 162 g / eq), triphenolmethane resin (HE900-80 manufactured by Air Water Chemical Co., Ltd.), hydroxyl equivalent 100 g / eq ), 4,4′-bismercaptomethylbiphenyl (additive-1) obtained in Reference Example 1, fused silica, and phosphorus-based curing accelerator in the proportions shown in Table 2 were used except that In the same manner as in Example 1, an epoxy resin composition was obtained and evaluated. The results are also shown in Table 2.

[Comparative Example 1]
In Example 1, an epoxy resin composition was prepared in the same manner as in Example 1 except that 4,4′-bismercaptomethylbiphenyl was not used and the amount of phenol biphenyl aralkyl resin was changed as shown in Table 2. Obtained and evaluated. The results are also shown in Table 2.

[Comparative Example 2]
In Example 2, the epoxy resin composition was used in the same manner as in Example 2 except that 4,4′-bismercaptomethylbiphenyl was not used and the amounts of the epoxy resin and phenol aralkyl resin were changed as shown in Table 2. Things were obtained and evaluated. The results are also shown in Table 2.

[Comparative Example 3]
In Example 5, epoxy resin was used in the same manner as in Example 5 except that 4,4′-bismercaptomethylbiphenyl was not used and the amounts of the epoxy resin and triphenolmethane type resin were changed as shown in Table 2. A resin composition was obtained and evaluated. The results are also shown in Table 2.

As is clear from the results in Table 1, when Examples 1, 3 and 4 are compared with Comparative Example 1, flame retardancy is improved from V-1 to V-0 by the blending of Additives 1-3. The elastic modulus during heating was reduced and the adhesion was improved. Also in the comparison between Example 2 and Comparative Example 2 using different epoxy resins and phenolic resin-based curing agents, the addition of additive-1 shortens the evaluation of _afterflame time _Fmax and _Ftotal , The elastic modulus was reduced and the adhesion was improved. Further, in comparison between Example 5 and Comparative Example 3 using another epoxy resin and a phenol resin-based curing agent, the flame retardance is improved from combustion to V-1 by the addition of additive-1, and the elasticity at the time of heat. The rate was reduced and the adhesion was improved.

2 is a ¹ H-NMR chart of 4,4′-bismercaptomethylbiphenyl obtained in Reference Example 1. FIG.

Claims (12)

An additive for epoxy resin comprising an aromatic sulfur compound having two or more functional groups represented by the following general formula (1) directly connected to an aromatic ring.

(Wherein n is 0 or an integer of 1 or more, R is hydrogen or a methyl group, and 2n Rs may be the same or different) The additive for epoxy resin according to claim 1, wherein the aromatic sulfur compound is a sulfur compound represented by the following general formula (2).

(In the formula, n is an integer of 0 or 1 or more, m is an integer of 1 or more, R is hydrogen or a methyl group, and may be the same or different. X is a direct bond, an alkylene group, S or O.) The additive for epoxy resins according to claim 2, wherein the sulfur compound represented by the general formula (2) is a sulfur compound represented by the following general formula (3).

(In the formula, R is hydrogen or a methyl group, and may be the same or different. X is a direct bond, an alkylene group, S or O.) The additive for epoxy resins according to claim 1, wherein the sulfur compound represented by the general formula (2) is a sulfur compound represented by the following general formula (4).

(In the formula, X is a direct bond, an alkylene group, S or O.) The additive for epoxy resins according to claim 1, wherein the aromatic sulfur compound having two or more functional groups represented by the general formula (1) is a sulfur compound represented by the following general formula (5).

(In the formula, R is hydrogen or a methyl group, and each may be the same or different.)   The epoxy resin composition formed by mix | blending the additive for epoxy resins of Claims 1-5 with an epoxy resin.   Furthermore, the epoxy resin composition of Claim 6 formed by mix | blending a phenol resin type hardening | curing agent.   Furthermore, the epoxy resin composition of Claim 6 or 7 formed by mix | blending an inorganic filler.   Furthermore, the epoxy resin composition of Claims 6-8 formed by mix | blending a hardening accelerator.   The epoxy resin composition of Claims 6-9 used for semiconductor sealing.   The epoxy resin hardened | cured material formed by hardening | curing the epoxy resin composition of Claims 6-10.   The semiconductor device formed by sealing a semiconductor element using the epoxy resin composition of Claim 10.

Images