TW201538557A - Epoxy resin and method for manufacturing the same, epoxy resin composition, and prepreg and cured product thereof - Google Patents

Abstract

The present invention discloses an epoxy resin composition and an epoxy resin. The epoxy resin composition yields a cured product which provides excellent curing property, high heat resistance, high mechanical strength, high heat conductivity, and excellent pyrolysis stability. Such epoxy resin composition may be used as a sealing material for electric or electronic parts or high heat dissipation sheet for circuit board substrate material. The present invention provides an epoxy resin and an epoxy resin composition having the epoxy resin, a curing agent, and an inorganic filler as essential components. The epoxy resin is obtained by epoxidizing a biphenol aralkyl resin with epichlorohydrin. The biphenol aralkyl resin is obtained by reacting 4,4'-dihydroxybiphenyl with aromatic condensing agent such as bischloromethylbiphenyl. A Mw of the epoxy resin measured by GPC ranges from 1,000 to 5,000 under the exception where the composition having n=0, and the composition having n=0 has an area % that is under 15% of the total area.

Description

Epoxy resin, epoxy resin composition and cured product thereof

The present invention relates to an epoxy resin composition, a cured product, and an epoxy resin used therein which are excellent in hardenability, high heat resistance, mechanical strength, high thermal conductivity, and thermal decomposition stability.

Epoxy resins are used industrially for a wide range of applications, but in recent years, their performance has been gradually improved. In particular, it is known that an epoxy resin having a liquid crystal original structure is used as an epoxy resin composition having high thermal conductivity. For example, Patent Document 1 discloses that a biphenol type epoxy resin and a polyhydric phenol resin hardener are required. The epoxy resin composition of the composition is excellent in stability and strength at high temperatures, and can be used in a wide range of fields such as bonding, casting, sealing, molding, and lamination. Further, Patent Document 2 discloses an epoxy compound having two liquid crystal original structures linked by a curved chain in a molecule. Further, Patent Document 3 discloses a resin composition containing an epoxy compound having a liquid crystal primordium.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 7-90052

[Patent Document 2] Japanese Patent Laid-Open No. Hei 9-118673

[Patent Document 3] Japanese Patent Laid-Open No. Hei 11-323162

[Patent Document 4] Japanese Patent Laid-Open No. Hei 4-255714

[Patent Document 5] Japanese Patent Laid-Open No. Hei 10-292032

[Patent Document 6] WO2011/074517

However, the epoxy resin having such a liquid crystal original structure has a high melting point, and when the mixing treatment is performed, the high-melting-point component is hardly dissolved, and dissolution remains, so that there is a problem that curability or heat resistance is lowered. In addition, high temperature is required when uniformly mixing such an epoxy resin with a hardener. At a high temperature, the hardening reaction of the epoxy resin proceeds rapidly and the gelation time becomes short. Therefore, there is a problem that the mixing treatment is severely restricted and it is difficult to handle. Further, when a third component which is soluble is added to compensate for such a disadvantage, the melting point of the resin is lowered to facilitate uniform mixing, but the cured product has a problem that the thermal conductivity is lowered.

On the other hand, Patent Document 4 and Patent Document 5 disclose a biphenol aralkyl type epoxy resin and a resin composition thereof, and are excellent in heat resistance, moisture resistance, mechanical properties, etc., but are not focused on low. Stress or thermal conductivity. Patent Document 6 describes an aralkyl type epoxy resin having a biphenyl ring and a composition containing the same.

An object of the present invention is to provide an epoxy resin composition which is excellent in hardenability and high in heat resistance, mechanical strength, and high in use in lamination, molding, casting, bonding, and the like. Thermal conductivity and thermal decomposition stability Excellent hardness and the like, and the epoxy resin composition can be used for electrical. Circuit board materials such as sealing materials for electronic parts and high heat radiation sheets. Further, another object is to provide an epoxy resin used in the epoxy resin composition.

The present invention is an epoxy resin characterized by having a weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) in an epoxy resin represented by the following general formula (1). The value other than the n=0 component is 1,000 to 5,000, and the n=0 component is 15% or less in terms of area%.

(here, n represents the number from 0 to 20)

Further, the present invention provides a method for producing an epoxy resin, which comprises reacting a biphenol compound with an aromatic condensing agent in an amount of from 0.1 mol to 0.55 mol with respect to 1 part of the biphenol compound. The aromatic condensing agent is reacted to obtain a polyvalent hydroxy resin represented by the following formula (a), and the step of removing the n=0 component is carried out, followed by reaction with epichlorohydrin.

[Chemical 2]

(here, n represents the number from 0 to 20)

Further, the present invention is an epoxy resin composition characterized in that the epoxy resin and a curing agent are essential components. The epoxy resin composition may comprise an inorganic filler as an essential component, and as part or all of the inorganic filler in this case, a thermal conductivity of 20 W/m may be used. An inorganic filler of K or more. Further, the epoxy resin composition is expanded in use in a state of being dissolved or suspended in a solvent.

Further, the present invention is a prepreg comprising a composite of the epoxy resin composition and a fibrous substrate. Further, the present invention is a cured product obtained by hardening the epoxy resin composition.

When the epoxy resin composition containing the epoxy resin of the present invention is heat-hardened, an epoxy resin cured product can be formed, which can provide hardenability, high heat resistance, mechanical strength, high thermal conductivity, and heat. Excellent in terms of decomposition stability, etc., suitable for use in electrical. Uses of sealing materials for electronic parts, circuit board materials such as high heat radiation sheets, etc.

1 is a GPC chart of epoxy resin A of the present invention.

2 is a GPC chart of epoxy resin B for comparison.

Figure 3 is a GPC diagram of epoxy resin C for comparison.

The epoxy resin of the present invention is represented by the formula (1). In the formula, n represents a number from 0 to 20. The average value (number average) of n is a range that satisfies the case where the weight average molecular weight (Mw) measured by GPC is 1,000 to 5,000 in terms of values other than the n=0 component, and the n=0 component is the area% of GPC. It is considered to be 15% or less of the whole; it is preferably in the range of 1 to 6 as a whole. Further, the content of the n=0 component is more preferably 2% to 8%, and the Mw is preferably 1,500 to 4,500.

The epoxy resin can be produced by reacting a polyhydric hydroxy resin represented by the above formula (a) with epichlorohydrin. However, it is not limited to this reaction method. Further, advantageously, the polyhydric hydroxy resin can be produced by reacting a biphenol with an aromatic condensing agent. Specifically, the method is as follows: a biphenol compound is reacted with an aromatic condensing agent in an amount of from 0.1 mol to 0.55 mol with respect to the biphenol compound 1 mol, and the aromatic condensing agent is 0.1 mol to 0.55 mol. (a) A method of reacting a polyhydric hydroxy resin represented with epichlorohydrin. Further, in the formula (a), n has the same meaning as the formula (1).

The biphenol of the synthetic raw material of the polyhydric hydroxy resin is 4,4'-dihydroxybiphenyl.

Examples of the aromatic condensing agent include 4,4'-bishydroxymethylbiphenyl, 4,4'-dichloromethylbiphenyl, 4,4'-bisbromomethylbiphenyl, and 4,4'-double Oxymethylbiphenyl, 4,4'-double B Oxymethylbiphenyl. From the viewpoint of reactivity, 4,4'-bishydroxymethylbiphenyl or 4,4'-bischloromethylbiphenyl is preferred, and from the viewpoint of reducing ionic impurities, it is preferably: 4 4'-bishydroxymethylbiphenyl, 4,4'-bismethoxymethylbiphenyl.

In the reaction of a biphenol and an aromatic condensing agent, an excess amount of a biphenol (difunctional phenolic compound) is used with respect to an aromatic condensing agent. The aromatic condensing agent is used in an amount of from 0.2 moles to 0.55 moles, preferably from 0.3 moles to 0.5 moles, relative to the biphenols. When the amount of the aromatic condensing agent used is more than 0.55 mol, the formation of the n=0 component is small, but the molecular weight itself is increased, and the softening point and the melt viscosity of the resin are improved. Therefore, the molding workability is hindered, and if it is less than 0.1. Mohr, after the reaction is completed, the amount other than the excess biphenol is increased, which is industrially unsatisfactory. When the molar ratio (aromatic condensing agent/biphenol) is increased within the above range, the average value of n is increased, and the content of n=0 is decreased. Therefore, by adjusting the molar ratio, Control the average value of n or Mw. Further, in the present invention, the n=0 component is removed by the subsequent step, whereby the content of the n=0 component can be largely controlled.

Usually, the reaction is carried out in the presence of a known acid catalyst such as a mineral acid or an organic acid. Examples of such an acid catalyst include mineral acids such as hydrochloric acid, sulfuric acid, and phosphoric acid; or organic acids such as formic acid, oxalic acid, trifluoroacetic acid, and p-toluenesulfonic acid; or zinc chloride, aluminum chloride, and ferric chloride. A Lewis acid such as boron trifluoride; or a solid acid such as activated clay, ceria-alumina or zeolite.

Usually, the reaction is carried out at 10 ° C to 250 ° C for 1 hour to 20 hours. Further, in the reaction, as the solvent, for example, methanol, ethanol, propanol, butanol, ethylene glycol, methyl cellosolve, ethyl cellosolve, diethylene glycol dimethyl ether, and the like are preferably used. An alcohol such as ethylene glycol dimethyl ether or an aromatic compound such as benzene, toluene, chlorobenzene or dichlorobenzene; and particularly preferred among these solvents are ethyl cellosolve, diethylene glycol dimethyl ether, and triethyl ethane. Diol dimethyl ether and the like. After the completion of the reaction, the obtained polyhydric hydroxy resin can be removed by distillation under reduced pressure, washed with water or reprecipitated in a poor solvent to remove the solvent, but it can also be used as a raw material for the epoxidation reaction in a state in which a solvent remains.

Further, in the present invention, after the completion of the reaction, the obtained polyhydric hydroxy resin is preferably subjected to a step of removing the n=0 component. In this step, for example, it is preferred to use a poor solvent which does not dissolve the n=0 component and dissolve the high molecular weight component of n=1 or more, and remove the n=0 component by filtration or the like. The poor solvent is not particularly limited as long as it does not substantially dissolve the n=0 component. For example, ethylene glycol, methyl cellosolve, ethyl cellosolve, diethylene glycol dimethyl ether, or the like can be preferably used. An alcohol such as triethylene glycol dimethyl ether or a good solvent of an aromatic compound such as benzene, toluene, chlorobenzene or dichlorobenzene may be mixed with acetone, methyl ethyl ketone, methyl isobutyl ketone or cyclohexane. Ketones such as ketones. In this step, the content of the n = 0 component can be greatly reduced, but it is advantageous that the content of the component of n = 0 is preferably 10% or less, more preferably 8% or less.

The step of removing the component of n=0 can also be carried out after epoxidation. The removal step performed after the epoxidation is preferably carried out in the same manner as the above step, using a lean solvent, by filtration or the like to remove the n=0 component. Since the epoxy resin has high solubility compared with the polyhydric hydroxy resin, the preferred poor solvent in this case is desirably less soluble. The poor solvent is not particularly limited as long as it does not substantially dissolve the n=0 component. For example, a ketone such as acetone, methyl ethyl ketone, methyl isobutyl ketone or cyclohexanone is preferred.

The epoxy resin of the present invention can be obtained by reacting the polyhydric hydroxy resin with epichlorohydrin The alcohol is reacted to produce. This reaction can be carried out in the same manner as the usual epoxidation reaction. For example, a method in which a polyvalent hydroxy resin is dissolved in excess epichlorohydrin is carried out at 50 ° C to 150 ° C, preferably 60 ° C in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. The reaction was carried out at ~120 ° C for 1 hour to 10 hours. At this time, the alkali metal hydroxide is used in an amount of from 0.8 mol to 1.2 mol, preferably from 0.9 mol to 1.0 mol, based on 1 mol of the hydroxyl group in the polyvalent hydroxy compound. Further, epichlorohydrin is excessively used with respect to a hydroxyl group in the polyhydric hydroxy resin, but usually it is 1.5 mol to 15 mol, preferably 2, with respect to 1 hydroxyl of the hydroxyl group in the polyvalent hydroxy compound. Mo Er ~ 8 Mo Er. After the completion of the reaction, the excess epichlorohydrin is distilled off, and the residue is dissolved in a solvent such as toluene or methyl isobutyl ketone, filtered, washed with water to remove the inorganic salt, and then the solvent is distilled off to obtain a pass. An epoxy resin represented by the formula (1). Further, in the case of epoxidation, the epoxy group of the epoxy compound to be produced is subjected to ring-opening and condensation to produce a small amount of the oligomerized epoxy compound, and the epoxy compound is not affected.

Further, the softening point or melting point of the epoxy resin can be easily adjusted by changing the molar ratio of the biphenol and the crosslinking agent (aromatic condensing agent) when synthesizing the polyvalent hydroxy resin as the epoxy resin raw material, but The softening point or the melting point is preferably 130 ° C or less, and particularly preferably 120 ° C or less, from the viewpoint of suppressing deterioration of physical properties due to dissolution of the high-melting component during the mixing treatment of the epoxy resin composition. When the softening point or the melting point is higher than the above, the physical properties such as hardenability or heat resistance tend to decrease. Further, in order to lower the softening point or the melting point, it is necessary to reduce the n=0 component having a high melting point, but generally, the biphenol is crosslinked and crosslinked in order to reduce the n=0 component. The molar ratio of the agent increases as the molecular weight increases, so there is a limit to the decrease in the softening point or melting point. On the other hand, in the epoxy resin of the present invention, since the n=0 component is small and the Mw is low, the properties of the cured product obtained by using the epoxy resin composition of the epoxy resin are improved.

The epoxy resin composition of the present invention contains the epoxy resin of the present invention and a curing agent as essential components. It is advantageous to use these as an essential component with an inorganic filler.

As a curing agent to be blended in the epoxy resin composition of the present invention, in the field of requiring high electrical insulating properties such as a semiconductor sealing material, it is preferred to use a polyhydric phenol as a curing agent. Specific examples of the curing agent are shown below.

Examples of the polyhydric phenols include dihydric phenols such as bisphenol A, bisphenol F, bisphenol S, bisphenol, hydroquinone, resorcin, catechol, biphenol, and naphthalenediol. And further, tris-(4-hydroxyphenyl)methane, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, phenol novolac, o-cresol novolac, naphthol novolac, two a ternary or higher phenol represented by a cyclopentadiene type phenol resin or a phenol aralkyl resin; further, a phenol, a naphthol or a bisphenol A, a bisphenol F, a bisphenol S, a bisphenol , 4,4'-biphenol, 2,2'-biphenol, hydroquinone, resorcinol, catechol, naphthalenediol and other binary phenols, and formaldehyde, acetaldehyde, benzaldehyde , p-hydroxybenzaldehyde, terephthalic acid, terephthalic acid dimethyl ether, divinylbenzene, diisopropenylbenzene, dimethoxymethylbiphenyl, divinylbiphenyl, diisopropenyl a polyphenolic compound synthesized by a reaction of a crosslinking agent such as a biphenyl group; a biphenyl aralkyl type phenol resin obtained from a phenol or a bischloromethylbiphenyl group, a naphthol, a dichloroparaxylene, or the like Combined A naphthol aralkyl resin or the like.

Further, other curing agent components may be used. For example, dicyandiamide, an acid anhydride, an aromatic amine, or an aliphatic amine may be used. One type of these hardeners may be used in the epoxy resin composition of the invention, or two or more types may be used in combination.

The amount of the hardener to be formulated is formulated in consideration of the equivalent balance of the epoxy group in the epoxy resin and the functional group of the hardener (hydroxyl group in the case of a polyhydric phenol). The equivalent ratio of the epoxy resin and the hardener is usually in the range of 0.2 to 5.0, preferably in the range of 0.5 to 2.0, and particularly preferably in the range of 0.8 to 1.5. When the amount is larger than the above range or smaller than the above range, not only the curability of the epoxy resin composition is lowered, but also the heat resistance and mechanical strength of the cured product are lowered.

Further, in the epoxy resin composition, as the epoxy resin component, another epoxy resin may be blended in addition to the epoxy resin represented by the general formula (1). As another epoxy resin in this case, a general epoxy resin having two or more epoxy groups in the molecule can be used. For example, there are: bisphenol A, bisphenol F, bisphenol S, bismuth bisphenol, 4,4'-biphenol, 3,3',5,5'-tetramethyl-4,4'-two An epoxide of a dihydric phenol such as hydroxybiphenyl, resorcinol or naphthalenediol, tris-(4-hydroxyphenyl)methane, 1,1,2,2-tetrakis(4-hydroxyphenyl) An epoxide of a trivalent or higher phenol such as ethane, a phenol novolak or an o-cresol novolak; an epoxide of a co-condensation resin obtained from dicyclopentadiene and a phenol, and a cresol, formaldehyde, and Epoxides of co-condensation resins obtained by alkoxy-substituted naphthalenes, epoxides of phenol aralkyl resins obtained from phenols and dichloro-p-xylene, and phenols and dichloromethylbiphenyl An epoxide of a biphenyl aralkyl type phenol resin obtained by a naphthol and a dichloro-p-xylene An epoxide such as a naphthol aralkyl resin synthesized. These epoxy resins may be used alone or in combination of two or more. Further, the epoxy resin of the present invention is preferably formulated in an amount of 5 wt% to 100 wt%, preferably 60 wt% to 100 wt%, and the epoxy resin is preferably 0 wt%. 40% by weight range.

Further, for the purpose of reducing the stress of the cured product, a crosslinked elastomer may be contained in the epoxy resin composition. If the crosslinked elastomer is blended, the occurrence of cracks in the package in the thermal shock test of the cured product can be remarkably reduced.

The content of the crosslinked elastomer is preferably in the range of 3 parts by weight to 30 parts by weight, preferably 5 parts by weight to 20 parts by weight, more preferably 5 parts by weight to 15 parts by weight per 100 parts by weight of the epoxy resin. If it is less than the above range, the low elasticity is not sufficiently exhibited. On the other hand, when the ratio is larger than the above range, not only the Tg of the cured product is lowered, but also the fluidity is lowered, and the moldability tends to be deteriorated.

As the crosslinked elastomer, a known one can be used, and from the viewpoint of improving the compatibility with the epoxy resin, a styrene rubber or an acrylic rubber is preferably used.

When the inorganic filler is used as an essential component, the inorganic filler may, for example, be spherical or crushed cerium oxide such as cerium oxide or cerium oxide, or alumina powder such as alumina or hydrated alumina. The glass powder or mica, talc, calcium carbonate or the like is preferably used in an amount of 70% by weight or more, particularly preferably 80% by weight or more, in the case of use in a semiconductor sealing material. The shape of the inorganic filler is not limited, and a spherical shape, a crushed shape, a flat shape, a fibrous shape, or the like can be used, and the particle diameter or the long diameter thereof is preferably in the range of 1 μm to 1000 μm. For the formation of prepreg The fiber-like base material preferably has a fiber length of 10 mm or more, and the amount of the inorganic filler to be blended therein is preferably in the range of 10% by weight to 70% by weight.

For the purpose of imparting higher thermal conductivity, the higher the thermal conductivity of the inorganic filler, the better. Preferably 20W/m. K or more, more preferably 30W/m. Above K, especially 50W/m. K or more. Moreover, it is preferred that at least a part of the inorganic filler, preferably 50% by weight or more, has 20 W/m. Thermal conductivity above K. Moreover, the average thermal conductivity of the inorganic filler as a whole is 20 W/m. K or more, 30W/m. K or more, and 50W/m. The order above K increases satisfaction.

Examples of the inorganic filler having such a thermal conductivity include inorganic powders such as boron nitride, aluminum nitride, tantalum nitride, tantalum carbide, titanium nitride, zinc oxide, tungsten carbide, aluminum oxide, and magnesium oxide.

In the epoxy resin composition of the present invention, other additives may be added in addition to the essential components.

The epoxy resin composition of the present invention may also be appropriately formulated with polyester, polyamine, polyimine, polyether, polyurethane, petroleum resin, enamel resin, ruthenium. An oligomer or a polymer compound such as a benzofuran resin or a phenoxy resin is used as another modifier. The amount of the other modifier or the like added is usually in the range of 2 parts by weight to 30 parts by weight based on 100 parts by weight of the epoxy resin.

Further, the epoxy resin composition of the present invention may be formulated with an additive such as a pigment, a refractory agent, a shake imparting agent, a coupling agent, and a fluidity improver.

The pigments include organic or inorganic extender pigments, flaky pigments, and the like. Examples of the shake imparting agent include: lanthanide, castor oil, and aliphatic amide wax (amide). Wax), oxidized polyethylene wax, organic bentonite (bentonite), and the like.

Further, in the epoxy resin composition of the present invention, a curing accelerator may be used as needed. If exemplified, there are amines, imidazoles, organic phosphines, Lewis acids, etc., specifically: 1,8-diazabicyclo(5,4,0)undecene-7, tri-ethylidene Tertiary amines such as amine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris(dimethylaminomethyl)phenol, 2-methylimidazole, 2-phenylimidazole, 2-B Imidazoles such as 4-methylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecylimidazole, tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenyl Organic phosphines such as phosphine and phenylphosphine, tetraphenylphosphonium. Tetraphenylborate, tetraphenylphosphonium. Ethyltriphenylborate, tetrabutylphosphonium. Tetrabutyl hydride such as tetrabutyl borate. Tetrasubstituted borate, 2-ethyl-4-methylimidazole. Tetraphenylborate, N-methylmorpholine. A tetraphenylboron salt such as tetraphenylborate. Usually, the hardening accelerator is added in an amount of from 0.2 part by weight to 5 parts by weight based on 100 parts by weight of the epoxy resin.

Further, if necessary, a resin composition of the present invention may be used as a release agent such as carnauba wax or OP wax, a coupling agent such as γ-glycidoxypropyltrimethoxydecane, or a coloring agent such as carbon black. , flame retardant such as antimony trioxide, lubricant such as calcium stearate.

The epoxy resin composition of the present invention can be advantageously used as a varnish state (referred to as varnish) in which a part or all of the organic solvent is dissolved. When a solvent-insoluble component such as an inorganic filler is contained, it is not necessary to dissolve it, but it is preferred to form a suspension state to form a uniform and uniform solution. The epoxy resin in the resin composition is preferably all dissolved, and the epoxy resin of the present invention has excellent solubility. It is a feature that the solid component is difficult to precipitate in a stored state. When a part of the epoxy resin in the varnish is separated into a solid matter, the properties of the obtained cured product are deteriorated.

In the epoxy resin composition of the present invention, it is advantageous to form a composition (varnish) in a state in which a resin component is dissolved in a solvent, and then to impregnate the composition (varnish) in a glass cloth, an aromatic polyamide nonwoven fabric, or a liquid crystal. After the polymer-based polyester nonwoven fabric or the like is used in a fibrous substrate, solvent removal is performed, whereby a prepreg obtained by combining an epoxy resin composition and a fibrous substrate can be formed. Further, depending on the case, the varnish may be applied to a sheet such as a copper foil, a stainless steel foil, a polyimide film, or a polyester film to form a laminate. Further, the laminate may be formed by laminating the prepreg layer or by laminating the prepreg and the sheet.

When the epoxy resin composition of the present invention is heat-cured, an epoxy resin cured product can be formed, and the cured product is excellent in low hygroscopicity, high heat resistance, adhesion, flame retardancy, and the like. The cured product can be obtained by molding a resin composition by a method such as casting, compression molding, or transfer molding. The temperature at this time is usually in the range of 120 ° C to 220 ° C.

[Examples]

Hereinafter, the present invention will be specifically described based on synthesis examples, examples, and comparative examples. The solvent in the synthesis example is diethylene glycol dimethyl ether.

Example 1

In a 2000 ml four-necked flask, 246.2 g of 4,4'-dihydroxybiphenyl, 574.5 g of diethylene glycol dimethyl ether, and 166.1 g of 4,4'-bischloromethylbiphenyl were placed, and stirred under a nitrogen stream. The temperature was raised to 170 ° C and the reaction was carried out for 2 hours. After the reaction, under reduced pressure A part of the diethylene glycol dimethyl ether was distilled off, and 546 g of toluene and 182 g of methyl isobutyl ketone were added, and the mixture was stirred. After cooling to room temperature, the n=0 body precipitated by filtration was removed, and the solvent was distilled off to obtain a solvent. Resin 240 g. 70 g of the obtained resin was dissolved in 207.5 g of epichlorohydrin and 31.1 g of diethylene glycol dimethyl ether. Then, 31.8 g of a 49% aqueous sodium hydroxide solution was added dropwise at 75 ° C for 3 hours under reduced pressure. The water distilled under reflux was separated from epichlorohydrin in a separation tank, and epichlorohydrin was returned to the reaction vessel, and the water was removed to the outside of the system to carry out a reaction. After completion of the reaction, the salt formed by the filtration was removed, and further washed with water and then distilled to remove epichlorohydrin to obtain 23 g of an epoxy resin (epoxy resin A). The obtained resin had an epoxy equivalent of 225 g/eq., n = 0 in the GPC measurement, and a molecular weight of Mw: 2,042, Mn: 1,138, and Mw/Mn: 1.795. The obtained resin had low crystallinity, and a clear melting point was not confirmed by a differential scanning calorimeter (DSC). The melt viscosity at 150 ° C is 3.04 Pa. s. Further, the GPC measurement was carried out under the conditions described in the examples.

Synthesis Example 1

77.5 g of 4,4'-dihydroxybiphenyl, 180.8 g of diethylene glycol dimethyl ether, and 52.3 g of 4,4'-bischloromethylbiphenyl were placed in a 1000 ml four-necked flask, and stirred under a nitrogen stream. The temperature was raised to 170 ° C and the reaction was carried out for 2 hours. After the reaction, a portion of diethylene glycol dimethyl ether was distilled off under reduced pressure, and 385.4 g of epichlorohydrin was added thereto, and 69.4 g of a 48% aqueous sodium hydroxide solution was added dropwise thereto at 62 ° C for 4 hours under reduced pressure. The water distilled under reflux was separated from epichlorohydrin in a separation tank, and epichlorohydrin was returned to the reaction vessel, and the water was removed to the outside of the system to carry out a reaction. After the reaction is over, it will be produced by filtration. The resulting salt was removed, and further washed with water to distill off epichlorohydrin to obtain 129 g of an epoxy resin (epoxy resin B). The epoxy equivalent was 196 g/eq., the n=0 body in the GPC measurement was 24%, and the molecular weight other than the n=0 component was Mw: 3,341, Mn: 1,599, and Mw/Mn: 2.089. The peak temperature in the DSC measurement is 126 ° C, and the melt viscosity at 150 ° C is 0.68 Pa. s.

Synthesis Example 2

77.5 g of 4,4'-dihydroxybiphenyl, 180.8 g of diethylene glycol dimethyl ether, and 31.4 g of 4,4'-bischloromethylbiphenyl were placed in a 1000 ml four-necked flask, and stirred under a nitrogen stream. The temperature was raised to 170 ° C and the reaction was carried out for 2 hours. After the reaction, a portion of diethylene glycol dimethyl ether was distilled off under reduced pressure, and 385.4 g of epichlorohydrin was added thereto, and 70.5 g of a 48% aqueous sodium hydroxide solution was added dropwise thereto at 62 ° C for 4 hours under reduced pressure. The water distilled under reflux was separated from epichlorohydrin in a separation tank, and epichlorohydrin was returned to the reaction vessel, and the water was removed to the outside of the system to carry out a reaction. After completion of the reaction, the salt formed by the filtration was removed, and further washed with water to distill off epichlorohydrin to obtain 102 g of an epoxy resin (epoxy resin C). The epoxy equivalent was 184 g/eq., and the n=0 body in the GPC measurement was 39%, and the molecular weight other than the n=0 component was Mw: 2,383, Mn: 1,337, and Mw/Mn: 1.782. The peak temperature in the DSC measurement is 138 ° C, and the melt viscosity at 150 ° C is 0.15 Pa. s.

Example 2, Example 3, Comparative Example 1 to Comparative Example 6

The epoxy resin A to epoxy resin C, the curing agent, and triphenylphosphine (hardening accelerator) obtained in Example 1 and Synthesis Example 1 and Synthesis Example 2 were kneaded in the amount shown in Table 1, and obtained. The resin composition was confirmed to have solvent solubility. In addition, further The inorganic filler and other additives were kneaded at a mixing ratio shown in Table 3 to prepare an epoxy resin composition. The values in the table indicate the parts by weight in the formulation.

Other components are shown below. Further, PN is used as a hardener, spherical alumina is used as an inorganic filler, carnauba wax is used as a mold release agent, and carbon black is used as a colorant.

Epoxy resin D: o-cresol novolac type epoxy resin (epoxy equivalent weight 200, softening point 65 ° C, manufactured by Nippon Steel Chemical Co., Ltd.)

PN: phenol novolac (PSM-4261 (manufactured by Qun Rong Chemical Co., Ltd.), OH equivalent of 103, softening point of 82 ° C)

Spherical alumina: Product name: DAW-100, manufactured by Electrochemical Industry Co., Ltd., thermal conductivity 38W/m. K

Triphenylphosphine: Product Name: Hokko TPP, manufactured by Beixing Chemical Industry Co., Ltd.

Carnauba wax: Product name: Purified Carnauba Wax No.1, manufactured by Cerarica Noda Co., Ltd.

Carbon black: Product name: MA-100, manufactured by Mitsubishi Chemical Corporation

The epoxy resin composition was molded at 175 ° C, and further baked at 175 ° C for 12 hours to obtain a cured test piece, which was then subjected to various physical properties. The results are shown in Table 3.

The test conditions of the epoxy resin, the epoxy resin composition, and the cured product are shown below.

1) Determination of epoxy equivalent

Using a potentiometric titration device, using methyl ethyl ketone as a solvent, adding bromination The tetraethylammonium acetic acid solution was measured by a potentiometric titration apparatus using a 0.1 mol/L perchloric acid-acetic acid solution.

2) Determination of molecular weight distribution

Using a GPC measuring device (manufactured by Tosoh, HLC-8220 GPC), one TSK protection column (made by Tosoh), one TSKgel 2000HXL (made by Tosoh), and TSKgel 3000H XL (Tosoh) were used for the column. One of them, one TSKgel 4000H XL (manufactured by Tosoh Corporation), the detector was set to RI, tetrahydrofuran was used as a solvent, and the flow rate was 1.0 ml/min, and the column temperature was 40 ° C.

3) Melting point

The DSC peak temperature was determined by a differential scanning calorimeter (SII NanoTechnology Co., Ltd., EXSTAR 6000 DSC/6200) at a temperature increase rate of 5 ° C/min. That is, the DSC peak temperature is taken as the melting point of the epoxy resin.

4) Melt viscosity

The measurement was carried out at 150 ° C using a CAP2000H rotary viscometer manufactured by BROOKFIELD.

5) Gel time (seconds)

The measurement was carried out at 175 ° C according to JIS K 6910.

6) Glass transfer point (Tg)

Tg was determined using a thermomechanical measuring device (SII NanoTechnology Co., Ltd., EXSTAR 6000 TMA/6100) at a temperature increase rate of 10 ° C/min.

7) Weight retention rate (wt%)

The weight retention ratio (wt%) was determined from the difference between the weight of the test piece after 1000 hours at 250 ° C and the weight of the test piece before heating using a thermostat equipped with a rotating frame.

8) Bending strength

According to JIS K6911, the measurement was carried out at room temperature by a three-point bending test method.

9) Thermal conductivity

The thermal conductivity was measured using a Transient Hot Wire Method using a LFA447 thermal conductivity instrument manufactured by NETZSCH.

10) Solvent solubility

The epoxy resin composition shown in Table 1 was prepared by using cyclopentanone in a solvent, and the resin solution in which the epoxy resin composition was dissolved so that the solid content concentration became 50 wt% was left at room temperature, and it was confirmed by the The solvent solubility was evaluated by the number of days (time) until the precipitates. The results are shown in Table 2.

[Industrial availability]

The cured epoxy resin obtained by heat-hardening the epoxy resin composition containing the epoxy resin of the present invention is excellent in curability, high heat resistance, mechanical strength, high thermal conductivity, thermal decomposition stability, and the like. Suitable for electrical use. Uses of sealing materials for electronic parts, circuit board materials such as high heat radiation sheets, etc.

Claims (9)

An epoxy resin containing an n=0 component, a n=1 component, and a n=2 or more component in an epoxy resin represented by the following general formula (1), by gel permeation chromatography The weight average molecular weight (Mw) to be measured is 1,000 to 5,000 in terms of values other than the component of n=0, Mw/Mn is 1.5 or more, and the component of n=0 is 15% or less in terms of area%. Here, n represents a number from 0 to 20. The epoxy resin according to claim 1, wherein the n=0 component is 8% or less in terms of area%. A method for producing an epoxy resin according to claim 1, characterized in that the biphenol is obtained by using an aromatic condensing agent in an amount of from 0.1 mol to 0.55 mol with respect to 1 mol of biphenol. The reaction is carried out with an aromatic condensing agent to obtain a polyhydric hydroxy resin represented by the following formula (a), and the step of removing the n=0 component is carried out to form an area % measured by gel permeation chromatography, n = A polyvalent hydroxy resin having a composition of 8% or less is reacted with epichlorohydrin to form an epoxy resin. Here, n represents a number from 0 to 20. A method for producing an epoxy resin according to claim 1, wherein the aromatic condensing agent is in an amount of from 0.1 mol to 0.55 mol per mol of biphenol. The phenol is reacted with an aromatic condensing agent to obtain a polyhydric hydroxy resin represented by the general formula (a), and reacted with epichlorohydrin to form an epoxy resin, and then a step of removing the n=0 component is performed to utilize the condensate. The area of % by gel permeation chromatography was 8% or less in the component of n=0. An epoxy resin composition comprising an epoxy resin as described in claim 1 and a curing agent as essential components. The epoxy resin composition according to claim 5, wherein the thermal conductivity is 20 W/m in the epoxy resin composition containing the epoxy resin, the hardener and the inorganic filler as essential components. The inorganic filler of K or more is a part or all of the inorganic filler. The epoxy resin composition according to claim 5, wherein the epoxy resin composition is in a state of being dissolved or suspended in a solvent. A prepreg characterized in that the epoxy resin composition according to claim 5 of the patent application is compounded with a fibrous substrate. An epoxy resin cured product characterized by: The epoxy resin composition described in 5 is hardened.