JPH07173234A - Allylnaphthol cocondensate and epoxy resin composition - Google Patents

Abstract

PURPOSE:To provide an allynaphthol cocondensate which has low m.p. and melt vidcosity, is useful as a curative for an epoxy resin, and gives a cured item excellent in heat resistance, moisture resistance, flexibility, etc., by selecting a specific allylnaphthol cocondensate. CONSTITUTION:An allylnaphthol cocondensate is selected which has a wt. average mol.wt. of 300-2,000, is represented by formula I [wherein A is an allylnaphthol compd. of formula II; B alpha-napthod; D is an (allyl)-naphotol compd. of formula III; E is beta=naphthol; R<1> to R<4> are each H, alkyl, OH, or allyl; R<5> is an aldehyde residue; and l, m, and n are each 0-10 provided when l=m=0 or when l=m=n=0, then D is the allylnaphthol compd.], and is produced by the cocondensation of an allylnaphthol compd., beta-naphthol, and an aldehyde.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel allylnaphthol cocondensate and an epoxy resin composition containing the cocondensate.

[0002]

2. Description of the Related Art Conventionally, in the field of electric / electronic parts, particularly semiconductor encapsulating materials, a method of encapsulating a semiconductor element with an epoxy resin composition has been widely used in order to protect it from the external environment. Has been adopted. This composition
It is composed of epoxy resin, curing agent, curing accelerator, filler and other additives. As an epoxy resin,
A resin obtained by epoxidizing a novolac resin obtained by the reaction of phenols and formaldehyde, in particular, a cresol novolac type epoxy resin is widely used, and a phenol-formaldehyde novolac resin is used as a curing agent.

However, the recent trend toward higher density and higher integration in semiconductor devices requires the encapsulant to be further improved in various properties such as heat resistance, moisture resistance and adhesion.

Particularly, in the case of mounting the semiconductor element by the surface mounting method, the package of the semiconductor element is 200
It is placed in an oven at a high temperature of about 260 ° C. and exposed to severe temperature conditions. Therefore, even if the above-mentioned epoxy resin composition is used, there is still a problem that cracks occur in the package of the semiconductor device, and the demand for high heat resistance, low water absorption and high adhesion to the cured product is becoming stronger. .

Novolak resins obtained by reacting naphthol and aldehyde have been proposed as those satisfying these requirements. This resin is intended to improve physical properties such as heat resistance and moisture resistance of a cured product by introducing a naphthol skeleton. In fact, these properties give excellent properties, but on the other hand, it has a high viscosity. Therefore, there are problems such as poor molding workability and poor adhesion.

The object of the present invention is that it is useful as a curing agent for epoxy resins and has excellent workability due to its low melting point and melt viscosity, and also has a high glass transition temperature, heat resistance, moisture resistance, adhesion and flexibility. A novel allylnaphthol co-condensate capable of providing a cured product having properties and free from cracks is provided.

Another object of the present invention is a novel epoxy resin composition having a high glass transition temperature, excellent heat resistance, moisture resistance, adhesiveness and flexibility, and capable of preventing cracks from being generated in a package. Is provided.

[0008]

The allylnaphthol cocondensate of the present invention is a compound represented by the following general formula (I) and having a weight average molecular weight of 300 to 2000.

[0009]

[Chemical 3]

The allylnaphthol cocondensate of the present invention has a weight average molecular weight of 3 represented by the following general formula (II).
It is a compound of 00-2000.

[0011]

[Chemical 4]

The allylnaphthol co-condensate of the present invention has an allyl group and β-naphthol introduced into the condensate of naphthols and aldehyde, and therefore has extremely low melt viscosity and excellent workability. That is, the introduction of an allyl group causes a steric hindrance effect on the molecule to cause a decrease in viscosity, and the use of β-naphthol causes a large amount of a dimer to be produced. Due to both of these effects, a cocondensate having an extremely low viscosity can be obtained.

When the cocondensate of the present invention is used as a curing agent for an epoxy resin, the resulting cured epoxy resin exhibits a high glass transition temperature and is excellent in heat resistance, moisture resistance, adhesion and flexibility.

The allylnaphthol cocondensate of the present invention has a weight average molecular weight of 300 to 200 obtained by cocondensing allylnaphthols, β-naphthol and aldehydes.
0 compound.

Further, 80% or less of this β-naphthol,
A cocondensate in which 70% or less is replaced with α-naphthol is also useful because of its low viscosity.

The aldehydes are preferably aliphatic aldehydes selected from formaldehyde and paraformaldehyde, or aromatic aldehydes selected from benzaldehyde, hydroxybenzaldehyde, salicylaldehyde and terephthalaldehyde.

The allyl group of allylnaphthols is present in the naphthalene nucleus in an amount of 1 to 2, but preferably 1 in order to accelerate the condensation reaction.

The weight average molecular weight of the allylnaphthol cocondensate of the present invention is 300 to 2,000. If it is less than 300, the number of OH groups in the molecule is too small, and the curing with epoxy becomes insufficient, and if it exceeds 2000, the melting point and viscosity of the resin become high and the workability becomes poor.

The epoxy resin composition of the present invention comprises the above allylnaphthol cocondensate and an epoxy resin.

The epoxy resin composition of the present invention containing the above allylnaphthol cocondensate as a curing agent preferably contains a curing accelerator, and in that case, it is particularly effective as a semiconductor encapsulating composition.

In the present specification, "epoxy resin"
Unless otherwise specified, the term means not only a resinous epoxy compound but also a low molecular weight epoxy compound.

The allylnaphthol cocondensate of the present invention may be any compound having a molecular structure in which allylnaphthols, β-naphthol and aldehydes are cocondensed, and can be produced, for example, by the following two methods.

(Method A) The naphthols are allylated in advance to synthesize allylnaphthols, β-naphthol and aldehydes are added thereto, and if necessary, an acid or a base is added to carry out a dehydration reaction in the same manner as in the usual synthesis of novolaks. Method.

(Method B) After a condensate is previously synthesized from naphthols, β-naphthol and aldehydes, an allyl group is introduced into the condensate by reacting with an allyl halide and a base and optionally water or an organic solvent. how to.

In the case of Method A, the naphthols to be allylated can be those having one or more allyl groups introduced into the molecule and one or more positions to which aldehydes can be added, such as α-naphthol and Examples thereof include dihydroxynaphthalene and α-naphthol and dihydroxynaphthalene partially substituted with an alkyl group, and α-naphthol is particularly preferable.

To allylate naphthols, (1)
A method in which naphthols and a base are added to water to form a phenolate, and then an allyl halide is added to react with it, impurities are washed with water, and then Claisen rearrangement is carried out by heating, (2) In the method of (1) above, halogenation is performed. A method of adding allyl dropwise over a long period of time, (3) a method of adding naphthols and allyl halide and, if necessary, an organic solvent and adding an aqueous base solution to the reaction to wash the impurities, and then performing Claisen rearrangement. Any method may be used.

Even if some unreacted naphthols remain, there is no problem because they are taken into the molecule of the condensate in the next cocondensation reaction.

Examples of aldehydes include formaldehyde, paraformaldehyde, acetaldehyde,
Aliphatic aldehydes such as propylaldehyde, butyraldehyde and glyoxal, aromatic aldehydes such as benzaldehyde, p-hydroxybenzaldehyde, salicylaldehyde and terephthalaldehyde can be used,
Of these, paraformaldehyde, aromatic benzaldehyde, p-hydroxybenzaldehyde, salicylaldehyde, and terephthalaldehyde are preferable. One of these aldehydes may be used for the reaction, or two or more of them may be used in combination for the reaction. Further, the amount of aldehyde used is 1 of the total amount of allylnaphthols and β-naphthol as raw materials and α-naphthol added as necessary.
It is preferably 0.30 to 0.85 mol per mol. If the amount of the aldehyde used is less than 0.30 mol, the average molecular weight of the cocondensate becomes small, and the heat resistance of the cured product of the epoxy resin composition decreases. Also, 0.8
If it exceeds 5 moles, when β-naphthol is used alone, the amount exceeds the amount required for the reaction, which is uneconomical and causes an odor problem. When β-naphthol and α-naphthol are used in combination, a high molecular weight product is produced. When it is formed, a high melt viscosity is generated, workability is deteriorated, and a problem occurs in moldability. Particularly, it is preferably 0.50 to 0.60 mol when β-naphthol is used alone and 0.50 to 0.75 mol when β-naphthol and α-naphthol are used in combination.

Allylnaphthols and β in the condensation reaction
-The molar ratio used with naphthol (including optionally added α-naphthol) is preferably in the range of 10:90 to 64:36. If the molar ratio of allylnaphthols used is smaller than this, the effect of lowering the viscosity and flexibility is not imparted, and if the molar ratio is large, the cocondensation reaction does not proceed smoothly.

The cocondensation reaction for obtaining the allylnaphthol cocondensation product of the present invention is carried out only by heating to a high temperature in order to facilitate control of the number of naphthalene nuclei.
In this case, the reaction temperature is preferably 60 to 180 ° C, and particularly preferably 80 to 160 ° C. Reaction is usually 1-1
It will be finished in about 0 hours. If necessary, a catalyst such as acid or base may be used.

Although the reaction can be carried out without solvent, it is preferable to use a solvent having a boiling point of 80 ° C. or higher and a low solubility in water, such as toluene, xylene or methyl isobutyl ketone.

After completion of the reaction, impurities may be removed by washing with water or the solvent and unreacted materials may be removed under reduced pressure, if necessary.

In the case of Method B, naphthols, β-naphthol and the above-mentioned aldehydes are used to previously synthesize a condensate by the above-mentioned condensation method or the like, and then the above-mentioned allylation method (1), ( By allylation using 2), (3), etc., the cocondensate of the present invention having the desired molecular structure can be obtained.

When the allylnaphthol cocondensate of the present invention is used as a curing agent for an epoxy resin, it may be used alone, but it may be a compound having two or more, preferably three or more phenolic hydroxyl groups in the molecule. It can also be used in combination with another curing agent. As other curing agents, for example, phenol or a substituted phenol (o-cresol, p-cresol, t-butylphenol, cumylphenol, phenylphenol, etc.) and an aldehyde compound are reacted in the presence of an acid catalyst or a basic catalyst. Examples thereof include a usual phenol resin made to react; a reaction product of resorcin and an aldehyde compound; polyvinylphenol and the like. The proportion of other curing agents is 70% by weight or less, preferably 50% by weight, based on the total curing agents.
It is the following.

The type of epoxy resin is not particularly limited, and conventionally known ones can be used. Examples thereof include bisphenol type, phenol novolac type, and cresol novolac type epoxy resins. Among these resins, those having a melting point exceeding room temperature and exhibiting a solid state or a highly viscous solution state at room temperature bring about good results.

The bisphenol type epoxy resin is usually an epoxy equivalent of 160 to 200 and a melting point of 50 to 1.
The one having an epoxy equivalent of 180 to 300 and the melting point of 50 to 130 ° C. is used as the phenol novolac type epoxy resin, and the epoxy equivalent of the cresol novolac type epoxy resin is 180 to 21.
Those having a melting point of 0 and a melting point of 60 to 110 ° C. are generally used.

The ratio of the epoxy resin to the curing agent is such that the equivalent ratio of the phenolic hydroxyl group of the curing agent to the epoxy group of the epoxy resin (epoxy group / phenolic hydroxyl group) is usually 1 / 0.8 to 1.2, preferably The range of 1 / 0.9 to 1.1 is preferable. When the epoxy resin and the curing agent are used in such a ratio, a cured product having excellent heat resistance and moisture resistance can be obtained.

As the curing accelerator, a usual curing catalyst can be used, and the type thereof is not particularly limited. Specific examples of the curing accelerator include, for example, triphenylphosphine, tris-2,6-dimethoxyphenylphosphine, tri-p.
-Phosphorus compounds such as tolylphosphine and triphenyl phosphite; imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole; 2 -Tertiary amines such as dimethylaminomethylphenol, benzyldimethylamine, α-methylbenzylmethylamine; 1,5-diazabicyclo [4.3.0] -5-nonene, 1,4-diazabicyclo [2.2. 2] Octane, organic bases of 1,8-diazabicyclo [5.4.0] -7-undecene, and the like.

The amount of the curing accelerator added is preferably 0.1 to 3.0% by weight in the epoxy resin composition from the viewpoint of heat resistance and moisture resistance.

The epoxy resin composition of the present invention may contain additives as required. Examples of the additive include a filler, a surface treatment agent for treating the surface of the filler, a flame retardant, a release agent, a colorant, and a flexibility-imparting agent.

The kind of the filler is not particularly limited, and examples thereof include crystalline silica powder, fusible silica powder, quartz glass powder,
Talc, calcium silicate powder, zirconium silicate powder,
Examples thereof include alumina powder and calcium carbonate powder. Among these fillers, silica-based fillers are preferable. The proportion of filler is 60 to 90% by weight of the total composition, preferably 7%.
It is 0 to 85% by weight. If the compounding amount of the filler exceeds 90% by weight, the fluidity of the composition is lowered and molding becomes difficult, and if it is less than 60% by weight, thermal expansion tends to increase.

Examples of the surface treatment agent include known silane coupling agents and the like, and examples of the flame retardant include antimony trioxide, antimony pentoxide, phosphate and bromide. Examples of the release agent include various waxes,
Carbon black etc. are mentioned as a coloring agent.
The flexibility-imparting agent includes, for example, silicone resin and butadiene-acrylonitrile rubber.

The method for preparing the epoxy resin composition of the present invention is not particularly limited and can be carried out according to a conventional method. In addition, conditions for encapsulating a semiconductor using the resin composition of the present invention can be appropriately selected and are not particularly limited. Explaining specifically an example of the sealing condition, for example, 175
Molding for 3 minutes at 100 ℃ / molding pressure 100kg / cm ² and
For example, after-curing at 80 ° C. for 5 hours. Usually, it is formed by transfer molding.

[0044]

EXAMPLES The embodiments of the present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

The analysis and identification of the compound were carried out by gel permeation chromatography (GPC method) and nuclear magnetic resonance spectrum (NMR). Below G
The measurement conditions of PC and NMR are shown.

(GPC analysis) Solvent: Tetrahydrofuran Flow rate: 0.8 ml / min Column: G4000H and G3000 manufactured by Tosoh Corporation
H and G2000H (series) with exclusion limit molecular weights of 400,000, 60,000 and 10,000, respectively.
Is. Carrier: Styrene / divinylbenzene copolymer (NMR) The NMR spectrum of the synthesized product was confirmed as being assigned to the following.

[Chemical 5]

Example 1 In a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet, 144 g (1 mol) of α-naphthol, 440 g of a 10% aqueous sodium hydroxide solution and 144 g of methyl isobutyl ketone were charged. Then, the mixture was heated to 80 ° C. with stirring to homogenize it to form a phenolate. To this reaction solution, 84.2 g (1.1 mol) of allyl chloride was added dropwise using a dropping funnel over 3 hours, and after completion of the addition, the mixture was stirred for 1 hour to react. After the reaction was completed, the reaction mixture was separated and washed with water, and the solvent was completely distilled off under reduced pressure. Next, the obtained reaction product was transferred to a reaction vessel, heated to 140 ° C. and stirred for 2 hours to cause a reaction to obtain allylnaphthol (OH group equivalent 184).

92 g of the above-mentioned allylnaphthol was placed in a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet.
(0.5 mol), β-naphthol 72 g (0.5 mol)
And paraformaldehyde 16.5 g (0.55 mol, converted to formaldehyde) (allylnaphthol and β-
Total naphthol: paraformaldehyde = 1: 0.5
5 (molar ratio) was charged, and the mixture was heated to 140 ° C. and stirred under a nitrogen stream for 3 hours to cause a reaction. Next, the mixture was heated to 200 ° C. and the unreacted material and water were removed under reduced pressure to obtain an allylnaphthol cocondensate represented by the following formula. The melting point of this compound was 61 ° C., and the melt viscosity at 150 ° C. was as low as 0.1 poise (hereinafter referred to as P), and the workability was excellent. (In the following examples and comparative examples, the measurement of viscosity was 1
Performed at 50 ° C. ) The weight average molecular weight (measured by GPC method, the same applies hereinafter) was 380, and the OH group equivalent was 178.

[0049]

[Chemical 6]

Example 2 Allylnaphthol 6 the same as that synthesized in the first stage of Example 1
1.6 g (0.34 mol), β-naphthol 48 g
(0.33 mol), α-naphthol 48 g (0.33 mol), xylene 86 g and paraformaldehyde 1
9.5 g (0.65 mol, converted to formaldehyde) (total of allylnaphthol, β-naphthol and α-naphthol: paraformaldehyde = 1: 0.65 (molar ratio))
A cocondensate was produced in the same manner as in Example 1 except that was added. Xylene was removed under heating and reduced pressure after the reaction. The obtained allylnaphthol cocondensate (shown by the following formula)
Has a low melting point of 65 ° C. and a viscosity of 0.4 P and is excellent in workability. Weight average molecular weight is 550, OH group equivalent is 1
It was 70.

[0051]

[Chemical 7]

Example 3 Allylnaphthol 9 same as that synthesized in the previous stage of Example 1
2 g (0.5 mol), β-naphthol 72 g (0.5 mol), toluene 184 g and benzaldehyde 58.
A cocondensate was produced in the same manner as in Example 1 except that 3 g (total of allylnaphthol and β-naphthol: benzaldehyde = 1: 0.55 (molar ratio)) was charged. Toluene was removed under heating and reduced pressure after the reaction. The melting point of the obtained allylnaphthol cocondensate (shown by the following formula) is 75.
The viscosity was as low as 0.2P at 0 ° C, and the work performance was excellent. The weight average molecular weight was 430 and the OH group equivalent was 212.

[0053]

[Chemical 8]

Example 4 Benzaldehyde 7 instead of paraformaldehyde
A cocondensate was produced in the same manner as in Example 2 except that 4.2 g was used. The obtained allylnaphthol co-condensate (shown by the following formula) had a melting point of 82 ° C. and a viscosity of 0.5 P, which was low and was excellent in workability. Weight average molecular weight is 680
The OH group equivalent was 222.

[0055]

[Chemical 9]

Example 5 A cocondensate was produced in the same manner as in Example 1 except that 67.1 g of p-hydroxybenzaldehyde was used instead of paraformaldehyde. The obtained allylnaphthol cocondensate (shown by the following formula) had a melting point of 95 ° C. and a low viscosity of 0.2 P, and was excellent in workability. The weight average molecular weight was 455 and the OH group equivalent was 150.

[0057]

[Chemical 10]

Example 6 Formalin water (37
%) 44.6 g was used to prepare a cocondensate in the same manner as in Example 1. The obtained allylnaphthol cocondensate (shown by the following formula) has a melting point of 70 ° C. and a viscosity of 0.4.
It was as low as P and had excellent workability. Weight average molecular weight is 3
At 90, the OH group equivalent was 180.

[0059]

[Chemical 11]

Example 7 Salicylaldehyde 6 instead of paraformaldehyde
A cocondensate was produced in the same manner as in Example 1 except that 7 g was used. The obtained allylnaphthol cocondensate (shown by the following formula) has a melting point of 78 ° C. and a low viscosity of 0.5 P,
It had excellent workability. Weight average molecular weight is 640, O
The H group equivalent was 112.

[0061]

[Chemical 12]

Example 8 A cocondensate was produced in the same manner as in Example 1 except that 49 g of terephthalaldehyde was used instead of paraformaldehyde. The obtained allylnaphthol cocondensate (shown by the following formula) had a melting point as low as 88 ° C and a viscosity as low as 0.8P, and was excellent in workability. Weight average molecular weight is 780
The OH group equivalent was 185.

[0063]

[Chemical 13]

[0064] without using the synthesized allyl naphthol in the preceding stage of Comparative Example 1 Example 1, alpha-naphthol 144g paraformaldehyde 2
A condensate was produced in the same manner as in Example 1 except that 2 g was used. The obtained condensate has a melting point of 86 ° C and a viscosity of 1
High as 8.3P, poor fluidity, and poor workability.
The weight average molecular weight was 1280 and the OH group equivalent was 165.

Comparative Example 2 Instead of paraformaldehyde, formalin water (37
%) And 0.5 g of paratoluene sulfonic acid were used to produce a condensate in the same manner as in Comparative Example 1. The obtained condensate has a high melting point of 131 ° C. and a viscosity of 76P.
Poor fluidity and poor workability. The weight average molecular weight was 1320 and the OH group equivalent was 178.

Examples 9 to 16 and Comparative Example 3 The following epoxy resin, curing agent, curing accelerator, filler, antimony trioxide, silane coupling agent, wax and carbon black are shown in Tables 1 and 2. The epoxy resin composition for semiconductor encapsulation was prepared by mixing in a ratio (parts by weight), kneading with a two-roll mill at a temperature of 70 to 110 ° C., then cooling and pulverizing.

Epoxy resin: o-cresol novolac type epoxy resin (epoxy equivalent 195, melting point 85 ° C.) Brominated phenol novolac type epoxy resin (epoxy equivalent 280, melting point 83 ° C.) Curing agent: obtained in Examples 1 to 8 Co-condensate Phenol novolac resin (hydroxyl group equivalent 106, melting point 8
0 ° C.) Curing accelerator: Triphenylphosphine filler: Spherical silica (BF1 of Mitsubishi Metals Co., Ltd.)
00)

The composition obtained was treated at 175 ° C. and 100 kg.
/ Cm ² , molded under curing conditions of 3 minutes, then 180
A post-cure was performed under the conditions of ° C and 6 hours to prepare a molded test piece. This test piece is an 80-pin four-way flat package (80-pin QFP, size 20 x 14 x 2 mm)
And the die pad size is 8 × 8 mm.

The semiconductor device thus obtained was subjected to a TCT test of −50 ° C./5 minutes to 150 ° C./5 minutes to check the number of cracks. In addition, the test piece,
A crack resistance test was performed by allowing the sample to stand in a constant temperature bath having a relative humidity of 85 ° C./85% RH to absorb moisture, and then immersing it in a solder melt at 260 ° C. for 10 seconds. The results are shown in Tables 3 and 4.

The bending strength (high temperature strength) at 200 ° C. of the obtained test piece, the glass transition temperature, the coefficient of thermal expansion,
The water absorption was examined after a humidification test at 85 ° C./85% RH for 500 hours. The results are shown in Tables 5 and 6.

[0071]

[Table 1]

[0072]

[Table 2]

[0073]

[Table 3]

[0074]

[Table 4]

[0075]

[Table 5]

[0076]

[Table 6]

[0077]

The allylnaphthol cocondensate of the present invention is
Has a low melting point and melt viscosity, and has excellent workability. When it is used as a curing agent for epoxy resin, the obtained epoxy resin cured product has a high glass transition temperature, heat resistance and moisture resistance, and cracks are less likely to occur in the package even during soldering.

The cured product of the epoxy resin composition of the present invention containing this allylnaphthol cocondensate as a curing agent has a high glass transition temperature and excellent heat resistance, and also has a high mechanical strength, a low water absorption rate and a low moisture resistance. Excellent in occurrence of cracks even during soldering. Therefore, the epoxy resin composition of the present invention is useful as a semiconductor encapsulating composition.

Claims (4)

[Claims] 1. An allylnaphthol cocondensate represented by the following general formula (I) and having a weight average molecular weight of 300 to 2,000. [Chemical 1] 2. An allylnaphthol cocondensate having a weight average molecular weight of 300 to 2000 represented by the following general formula (II). [Chemical 2] 3. An allylnaphthol cocondensate having a weight average molecular weight of 300 to 2000 obtained by cocondensing allylnaphthols, β-naphthol and aldehydes. 4. An epoxy resin composition comprising the allylnaphthol cocondensate according to any one of claims 1 to 3 and an epoxy resin.