JP2847632B2 - Method of curing epoxy resin with excellent heat resistance and cured epoxy resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has excellent heat resistance, toughness, and other mechanical properties, and is an epoxy resin-based curable resin composition used for adhesives, sealants for electric and electronic parts, and various structural materials. The present invention relates to a product, a method for curing the same, and a cured molded product thereof. Specifically, according to the curing method of the present invention, the basic skeleton
Specific range of high melting point epoxy resin with biphenyl nucleus
Is cured without completely melting at the temperature of
Thus, the obtained cured product has birefringence and stereoregularity,
(Hardened in a state of complete melting of the epoxy resin) Normal
Glass transition point is higher than cured product obtained by
In addition , it provides an epoxy resin cured molded product excellent in both heat resistance and toughness.

[0002]

2. Description of the Related Art Conventionally, epoxy resins typified by bisphenol A type epoxy resins have excellent properties such as adhesiveness and electrical properties, so that they can be used for paints, casting materials for electrical parts,
It is widely used for applications such as laminates, adhesives, and sealing materials for electrical and electronic components. However, in recent years, epoxy resins have tended to be used under more severe use conditions in each application, and conventional epoxy resins may have insufficient heat resistance, toughness, impact resistance, moisture resistance, and the like. Was.

[0003] For this purpose, many developments of epoxy resins with improved properties have been made. For example, in the field of sealing materials for electronic components, as a method of increasing heat resistance, a method of using various polyfunctional epoxy resins obtained by glycidylating a polyfunctional phenol, as represented by epoxy cresol novolak, has been proposed. (Japanese Patent Laid-Open No. 3-1
No. 7117).

[0004] However, when such a polyfunctional epoxy resin is used, although the heat resistance of the cured product is improved, there is a problem that the toughness of the cured product is reduced due to an increased crosslink density. Further, as a new attempt to improve heat resistance and toughness, JP-A-63-23931 or JP-A-4-233935 discloses that a relatively rigid skeleton (mesogen) is contained in a molecule, and the temperature is within a certain temperature range. A method has been proposed in which an epoxy resin exhibiting liquid crystal properties is mixed with an amine-based curing agent, and the epoxy resin is cured within a temperature range in which the epoxy resins exhibit liquid crystal properties.

[0005]

The epoxy resin cured product obtained by this method is certainly an epoxy resin cured product obtained by curing a mixture of an epoxy resin and a curing agent having the same composition from an isotropic liquid state. Although high strength and high impact resistance are shown in comparison with the product, the heat resistance represented by the glass transition point is about 170 ° C. because the exemplified epoxy resin skeleton is slightly bent and has flexibility. This is the same level as the bisphenol A type epoxy resin most commonly used at present, and it cannot be said that the heat resistance is sufficiently improved. Therefore, an object of the present invention is to provide a cured epoxy resin product having excellent heat resistance and toughness, and a method for obtaining the cured epoxy resin product.

[0006]

As a result of various studies on the above problems, the present inventor has selected (a) a biphenyl group as a mesogen having a rigid skeleton, and (b) a polymerization degree of the epoxy resin of at least a certain level. A high epoxy resin with a high melting point, mixed with the epoxy resin with a curing agent,
(C) A cured product obtained by a usual curing method by curing within a specific temperature range of 150 ° C. or higher and the melting point or lower .
It has been found that the glass transition point is higher than that of, and it is possible to give an epoxy resin cured molded product in both heat resistance and toughness, and the present invention has been completed.

That is, the present invention provides: As an essential component, (a) a compound represented by the formula (I):

Embedded image [Wherein A is a group represented by the formula (II):

Embedded image And n represents an integer of 0 or more. A thermosetting resin composition comprising an epoxy resin having a melting point of 170 ° C. or higher and a curing agent (b) at a temperature of 150 ° C. or higher and a melting point of the epoxy resin or lower. provide. Also,

In the formula (I), A represents the following formula (III): It is also characterized by using an epoxy resin represented by Further, as an essential component, (a) Formula (1): [Wherein A is a group represented by the formula (II): Alternatively, formula (III): And n represents an integer of 0 or more. ] Represented by
(B) a curing agent consisting of an epoxy resin having a
A birefringent thermosetting resin composition . As an essential component, (a) Formula (1): [Wherein A is a group represented by the formula (II): Alternatively, formula (III): And n represents an integer of 0 or more. ], A birefringent epoxy resin-cured injection-molded product, extruded product, or compression obtained by curing a thermosetting resin composition comprising an epoxy resin having a melting point of 170 ° C or higher and a curing agent (b). A molded article or film is provided.

Hereinafter, the present invention will be described in detail. (A) Epoxy resin The epoxy resin (a) used in the present invention basically has the following characteristics. That is, formula (I):

Embedded image

[Wherein A is the formula (II):

Embedded image Alternatively, formula (III):

Embedded image And n represents an integer of 0 or more. ] And having a melting point of 170 ° C. or higher.

In the structural formula of the formula (I), n represents the number of repetitions and is an integer of 0 or more, but this value is uniquely limited by the molecular weight, melting point and the like. The number of repetitions has a number average value from the viewpoint that the produced epoxy resin itself is composed of various mixtures, but is generally 0.05 to 10, preferably 0.1 to 5, more preferably 0.1 to 5. 3 to 2. X-ray diffraction analysis shows that the epoxy resin (a) in the present invention has crystallinity. And its melting point is 170 ° C. or higher, preferably 18 ° C.
0 ° C to 350 ° C, more preferably 190 ° C to 300 ° C,
Particularly preferably, the temperature is from 200C to 280C. If the melting point of the epoxy resin (a) is too high than 350 ° C., the heat resistance of a cured molded product obtained by curing decreases, and
If the melting point is lower than 170 ° C., the effect of the present invention is undesirably reduced. The measurement of the melting point in the present invention was performed by heating at a rate of 1 ° C./min using a trace melting point measuring apparatus MP-J3 manufactured by Yanaco.

(B) Method for Producing Epoxy Resin In order to produce the epoxy resin (a) in the present invention, it is desirable to use the following method. That is, (i) Part 1: the following formula (IV):

Embedded image (Where A is the same as in the formula (I) and m is an integer of 0 or more) represented by the formula (V):

Embedded image And a dihydroxybiphenyl compound represented by the formula (1) in the presence or absence of a catalyst.

The reaction ratio of the epoxy resin (C) having a temperature of less than 170 ° C. and the dihydroxybiphenyl compound (d) can be varied in a wide range according to the performance range of the obtained epoxy resin. 9, preferably in a molar ratio of 0.1 to 0.7, more preferably 0.2 to 0.7
0.5. If the reaction ratio is less than 0.05, the effect of improving the heat resistance is not sufficient, which is not preferable.
When it exceeds, the fluidity of the epoxy resin decreases, and as a result,
The uniformity of the cured molded article obtained by curing the epoxy resin is reduced.

In producing the epoxy resin of the present invention, the reaction can be carried out in an organic or inorganic solvent in which the starting materials are dissolved, but it is desirable to carry out the reaction without a solvent in view of the homogeneity of the reaction system. Examples of the catalyst used here include a basic catalyst, a quaternary ammonium salt-based catalyst, and a phosphorus-based catalyst. Examples of the basic catalyst include sodium hydroxide, potassium hydroxide, lithium hydroxide, tributylamine, triethylamine, triisopropylamine, benzyldiethylamine, 2-phenylimidazole, imidazole, N-methylimidazole and the like.

Examples of quaternary ammonium salt catalysts include:
Tetramethylammonium chloride, benzyltrimethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride,
Tetrabutylammonium bromide and the like can be mentioned. Examples of the phosphorus-based catalyst include triphenylphosphine, trimethylphosphine, benzyltriphenylphosphonium bromide, amyltriphenylphosphonium bromide, benzyltriphenylphosphonium iodide, and triphenylphosphonium iodide. The amount of the catalyst to be used is 1 ppm to 1% by weight, preferably 5 ppm to 1000 ppm, particularly preferably 10 ppm to 500 ppm, based on the epoxy resin represented by the formula (IV) and having a melting point of less than 170 ° C.

If the amount of the catalyst used is too small, less than 1 ppm, the reaction rate will be slow, and if it is more than 1% by weight, a side reaction will proceed to form a gel, or the epoxy resin cured molded article will be produced. When the physical and electrical characteristics are deteriorated or when used as a sealing material for an electronic component, the aluminum wiring is easily corroded, which is not preferable. Further, the reaction temperature is from 80 ° C. to 280 ° C., preferably 1 ° C.
00 ° C to 250 ° C, more preferably 120 ° C to 220 ° C
It is. When the reaction temperature is lower than 80 ° C, the progress of the reaction is too slow, and when the reaction temperature is higher than 280 ° C, the resin starts to thermally decompose.

The reaction may be carried out in a solvent or in the absence of a solvent. Examples of the solvent to be used include ketones such as methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, acetone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, diisobutyl ketone, acetonitrile acetone, holon, methyl cyclohexanone, acetophenone; diethyl ether; Diisopropyl ether, dioxane, furan, tetrahydrofuran, diethylene glycol dimethyl ether, diethylene glycol diethyl ether,
Ethers such as diethylene glycol dibutyl ether and acetal;

Esters such as ethyl acetate, butyl acetate, diethylene glycol monoacetate, ethylene carbonate and propylene carbonate; methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, 1-hexanol,
Alcohols such as -hexanol, 3-hexanol, 1-pentanol, 2-pentanol, 3-pentanol and glycerin; hydrocarbons such as hexane, cyclohexane, benzene, toluene, xylene and ethylbenzene; halogens such as chloroform, carbon tetrachloride, chlorobenzene and dichloroethane. Hydrocarbons; nitrogen compounds such as nitrobenzene, acetonitrile, pyridine, dimethylformamide, N-methylpyrrolidone and dimethylacetamide; and sulfur compounds such as dimethylsulfoxide.

Before the start of the reaction or at the initial stage of the reaction, the reaction system is temporarily heated to 280 ° C. to 300 ° C. to dissolve the biphenyl compound in the reaction system, and then cooled to a predetermined reaction temperature. Alternatively, an epoxy resin having a melting point of less than 170 ° C. may be added to a previously melted biphenyl compound to homogenize the reaction system and then proceed with the reaction at a predetermined temperature.

(Ii) Part 2 The epoxy resin (a) of the present invention is represented by the formula (V)
To a mixture of a dihydroxybiphenyl compound (d) represented by the formula (I) and an epihalohydrin (e) represented by epichlorohydrin, epibromohydrin, etc., at once or continuously, in the presence or absence of a catalyst. It can also be obtained by adding and reacting, washing with water after the reaction, and then distilling off excess epihalohydrin. The reaction ratio between the dihydroxybiphenyl compound (d) and the epihalohydrin (e) can be a wide ratio in accordance with the performance range of the obtained epoxy resin, but the molar ratio is 1.02.
To 5.0, preferably 1.1 to 3.0, more preferably 1.2 to 2.0.

If the reaction ratio is less than 1.02, the fluidity of the epoxy resin is lowered, and the uniformity of the cured molded product obtained by curing the epoxy resin is lowered, which is not preferable. If it exceeds, the melting point of the obtained epoxy resin is low due to a low molecular weight, and the effect of improving the heat resistance is not sufficient. Examples of the alkali used include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, and alkaline earth metal hydroxides such as calcium hydroxide. These alkalis may be used as they are, or may be used after being dissolved in a solvent such as water, methanol or ethanol.

It is preferable to add water or alkali generated during the reaction during the reaction while removing the entrained water out of the reaction system, since the chlorine content of the obtained epoxy resin becomes low. . As a method for removing water, a method in which water in the reaction system is distilled off by azeotropic distillation with epihalohydrin, the distillate is separated into an aqueous phase and an organic phase, and only the organic phase is returned to the reaction system. Is exemplified. The catalyst used may be the same as in (i) above. If necessary, a solvent may be used in combination, or the reaction may be carried out without a solvent.

(Iii) Part 3 As another method for producing the epoxy resin (a) in the present invention, a dihydroxybiphenyl compound (d) represented by the formula (V) and an epihalohydrin (e) are added in the presence of a catalyst. After the reaction to form the halohydrin compound, a method of performing a dehydrochlorination reaction using the alkali exemplified above is also exemplified. The reaction ratio between the dihydroxybiphenyl compound (d) and the epihalohydrin (e) is the same as that in the case of the above-mentioned (ii), and can be handled in substantially the same manner. If necessary, a solvent may be used in combination, or the reaction may be carried out without a solvent.

The catalyst used in this reaction includes a basic catalyst, a quaternary ammonium salt catalyst, a phosphorus catalyst and the like. Examples of basic catalysts are tributylamine,
Examples include triethylamine, triisopropylamine, benzyldiethylamine, 2-phenylimidazole, imidazole, N-methylimidazole and the like. Examples of the quaternary ammonium salt catalyst include tetramethylammonium chloride, benzyltrimethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide and the like.

Examples of the phosphorus-based catalyst include triphenylphosphine, trimethylphosphine, benzyltriphenylphosphonium bromide, amyltriphenylphosphonium bromide, benzyltriphenylphosphonium iodide, and triphenylphosphonium iodide. Even during the dehydrochlorination reaction, it is preferable to remove water in the reaction system in the same manner as in the case (ii) because the chlorine content of the epoxy resin is reduced.

In the above cases (ii) and (iii), specific examples of the dihydroxybiphenyl compound represented by the formula (V) include 4,4′-dihydroxybiphenyl, 2,4′-dihydroxybiphenyl, 2,2 '-Dihydroxybiphenyl and the like. The above (ii)
In the case of (iii) and (iii), the amount of the catalyst to be used is
, That is, 1 ppm to 1% by weight, preferably 5 ppm to 1000 ppm, particularly preferably 10 ppm to 1000 ppm.
ppm to 500 ppm.

If the amount of the catalyst used is too small, less than 1 ppm, the reaction rate will be slow, and if it is more than 1% by weight, a side reaction will proceed to form a gel, or the epoxy resin cured molded article will not be produced. When the physical and electrical characteristics are deteriorated or when used as a sealing material for an electronic component, the aluminum wiring is easily corroded, which is not preferable. It may be.

(C) Method of Curing Epoxy Resin (i) Method of Curing The method of curing the curable resin composition according to the epoxy resin (a) of the present invention comprises a high melting point resin having a biphenyl nucleus in a basic skeleton.
The epoxy resin is not completely melted at a specific temperature range
Thus, the curing reaction is advanced while controlling the molecular motion of the epoxy resin, and the heat resistance is improved by utilizing the high degree of orientation of the molecular chains. Therefore, the epoxy resin cured molded article obtained is had not a group for advanced orientation have a birefringent property and stereoregularity, found in conventional epoxy resins in terms of chromatic <br/> a high glass transition temperature Is a point that shows no specificity. Here, “birefringence” can be observed with a polarizing microscope, a spectrophotometer, or the like. Further, “stereoregularity” can be confirmed by the presence or absence of a peak other than a broad halo light by X-ray diffraction analysis.

The curing temperature of the curable resin composition of the present invention is as follows:
Above 150 ° C. and below the melting point of the epoxy resin, preferably 1
70 ° C. or higher and lower than the melting point of the epoxy resin, more preferably 1
It is necessary that the temperature is not lower than 80 ° C. and not higher than the melting point of the epoxy resin. In this case, if the temperature is lower than 150 ° C., the fluidity of the composition is almost lost, and an epoxy resin molded article having a predetermined shape cannot be obtained. Further, if the curing temperature is equal to or higher than the melting point of the epoxy resin, the curing reaction during the The molecular motion of the epoxy resin cannot be controlled, and the effect of the present invention does not appear. Further, the curing reaction may be advanced by the curing method of the present invention, and after the fluidity of the epoxy resin composition is lost, the curing temperature may be increased to a temperature equal to or higher than the melting point of the epoxy resin, and post-curing may be performed.

The epoxy resin composition of the present invention basically comprises a specific epoxy resin (a) and a curing agent (b) as essential components. As the component (a) constituting the main component of the epoxy resin composition of the present invention, the above-mentioned novel epoxy resin may be used alone, or may be used in combination with a small amount of another epoxy resin as needed. Other epoxy resins that can be used in combination include (a) diglycidyl ethers of bisphenol A, (b) epoxyphenol novolaks, (c) epoxy cresol novolaks, (d) other; phthalic acid or hexahydrophthalic acid and epichlorohydrin Epoxy resins obtained from parahydroxybenzoic acid and epichlorohydrin, epoxy resins obtained from aromatic amines such as tolylidine and aniline and epichlorohydrin, vinylcyclohexene dioxide, 1,4-butanediol diglycidyl Ether, 1,6-butanediol diglycidyl ether and the like.

(Ii) Curing agent (b) As the curing agent used in the present invention, an amine-based curing agent,
Acid anhydride-based curing agents, phenol-based curing agents, imidazole-based curing agents, cationic curing agents can be mentioned,
It is desirable to use an amine-based curing agent. Examples of the amine-based curing agent include ethylenediamine, 1,3-diaminopropane, 1,4-diaminopropane, hexamethylenediamine, 2,5-dimethylhexamethylenediamine, trimethylhexamethylenediamine, diethylenetriamine, iminobispropylamine, Bis (hexamethylene) triamine,

Triethylenetetramine, tetrachloro-
p-xylylenediamine, m-xylylenediamine, p
-Xylylenediamine, m-phenylenediamine, o-
Phenylenediamine, p-phenylenediamine, 2,4
-Diaminoanisole, 2,4-toluenediamine,

2,4-diaminodiphenylmethane, 4,
4'-diaminodiphenylmethane, 2,4-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, m-aminophenol, m-aminobenzylamine, triethylamine, benzyldimethylamine,
2- (dimethylaminomethyl) phenol, 2,4,6
-Tris (dimethylaminomethyl) phenol, triethanolamine, methylbenzylamine, tomide (Fuji Kasei), versamide, genamide (Henkel Shisui), lacqueramide (Dainippon Ink), sanmide (Sanwa Chemical), polymide (Sanyo Chemical) And the like, of which the use of 4,4′-diaminodiphenylsulfone is preferred.

Examples of the acid anhydride-based curing agent include dodecenyl succinic anhydride, polyadipic anhydride, polyazeleic anhydride, polysebacic anhydride, poly (ethyl octadecane diacid) anhydride, and poly (phenylhexadecane dianhydride). Acid) anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylhymic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, methylcyclohexenedicarboxylic anhydride, phthalic anhydride Acid, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol bistrimellitate, heptic anhydride, tetrahydrophthalic anhydride, etc., of which use of methyl hexahydrophthalic anhydride Desirable. Examples of the phenolic curing agent include phenol novolak, cresol novolak, catechol novolak and the like, and among them, phenol novolak is preferred.

As the imidazole-based curing agent, for example,
1-methylimidazole, 2-methylimidazole, 2
-Ethyl-4-methylimidazole, 2-undecylimidazole, 2-hepdecylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-
Cyanoethyl-2-ethyl-4-methylimidazole,
2-methylimidazole,

1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2-methylimidazolium isocyanurate, 2- Phenylimidazolium isocyanurate, 2,4-diamino-6- [2-methylimidazolyl- (1)]-ethyl-S-triazine,
2,4-diamino-6- [2-ethyl-4-methylimidazolyl- (1)]-ethyl-S-triazine, 2,4
-Diamino-6- [2-undecylimidazolyl-
(1)]-Ethyl-S-triazine, 2-phenyl-
4,5-methylimidazole,

2-phenyl-4-methyl-5-hydroxymethylimidazole, 1-cyanoethyl-2-phenyl-4,5-di (cyanoethoxymethyl) imidazole, 1-dodecyl-2-methyl-3-benzylimidazolium Chloride, 1,3-dibenzyl-2-methylimidazolium chloride and the like.
The use of 2-ethyl-4-methylimidazole is preferred. Examples of the cationic curing agent include boron trifluoride and boron trifluoride-amine complex. Curing agent (b)
The compounding amount of the epoxy resin (a) varies depending on the degree of polymerization of the epoxy resin (a) and the type of the curing agent, and cannot be uniquely defined. is there.

(Ii) Other additives In the present invention, if necessary, a curing accelerator, an inorganic filler, a flame retardant, a coupling agent, a release agent, a colorant, a leveling agent, a repelling agent, an antifoaming agent Agents and the like can be added. Further, a reinforcing agent such as glass fiber, glass cloth, and carbon fiber may be contained. Examples of the curing accelerator used include the compounds exemplified above as the amine-based curing agent and the imidazole-based curing agent, and phosphorus compounds such as triphenylphosphine and tributylphosphine.

As the inorganic filler used, alumina, asbestos, carbon black, graphite, diatomaceous earth, magnesium oxide, titanium oxide, aluminum hydroxide,
Quartz powder, fused silica powder, talc, barite, mica and the like can be mentioned. Examples of the release agent include natural wax, synthetic wax, higher fatty acid and its metal salt, paraffin and the like. Since carbon or the like has a function of a conductive agent as a coloring agent, it is particularly desirable for use in electric / electronic parts. Desirable non-halogen flame retardants include, for example, inorganic fillers, antimony trioxide, antimony pentoxide, phosphoric acid and phosphorus compounds. Examples of the coupling agent include epoxy silane, vinyl silane, amino silane, borane compound, alkoxy titanate compound, and aluminum chelate compound.

The method of mixing the epoxy resin of the component (a) of the present invention, the curing agent of the component (b), and additives such as a curing accelerator and a filler compounded as necessary is as follows. , A kneader, an extruder, a roll and the like can be used. For the method of curing the epoxy resin of the present invention, general molding methods such as casting, transfer molding, and compression molding can be applied. Among them, silicone rubber, butyl rubber, polyfluorinated ethylene, Teflon, vinyl chloride, etc. Molded rubber, or modified PPE, engineering plastics such as nylon, polycarbonate, polyester, super engineering plastics such as polyimide, polyaryl ether, or stainless steel, and open a mold of a predetermined shape. A small epoxy resin cured molded product can be obtained. The shape of the epoxy resin cured molded product of the present invention is particularly suitable for applications such as insulating materials such as electric and electronic devices, laminates, sealing materials, and the like, such as films, injection molded products, transfer molded products, cast products, and the like. Compression molded products can be mentioned.

The method for curing the epoxy resin of the present invention comprises:
Even if the epoxy resin of the component (a) and the curing agent of the component (b) and additives such as a curing accelerator and a filler compounded as necessary are mixed without heating and melting, and directly cured, A good method is to add each component to a molten epoxy resin, or heat and melt a pre-blended mixture, homogenize it, quench it, pulverize the obtained solid, and then heat and cure it at a predetermined temperature. Is preferred since an epoxy-cured molded article having a uniform composition can be obtained.

[0042]

The present invention will be described below in more detail with reference to Examples, which do not limit the scope of the present invention. In the examples, "parts" indicates parts by weight. The evaluation of various physical properties in the examples was performed by the following methods. Epoxy equivalent The epoxy resin is dissolved with benzyl alcohol and 1-propanol. An aqueous solution of potassium iodide and a bromophenol blue indicator were added to this solution, and titration was performed with 1 N hydrochloric acid. The point at which the reaction system turned from blue to yellow was defined as an equivalent point. From the equivalent point, the epoxy equivalent of the resin is calculated according to the following equation. Epoxy equivalent (g / eq.) = 1000 × W / (V × N
× F) W: Weight of sample (g) V: Titration (ml) N: Normality of hydrochloric acid used for titration (N) F: Factor of hydrochloric acid used for titration

Melting point 1 ° C. using a trace melting point measuring device MP-J3 manufactured by Yanaco Co., Ltd.
Per minute. Using a birefringence spectrophotometer (U-3000, manufactured by Hitachi), the polarizer and the analyzer are in a crossed Nicols state to obtain a background, and then a film thickness of 60 μm or more between the polarizer and the analyzer is 100 μm. When an epoxy cured product film having a size of less than micron was set and the transmittance of light at 700 nm was 1% or more, it was determined that the film had birefringence.

Stereoregularity X-ray diffraction analysis was performed, and in addition to the broad halo peak,
When a peak was observed between 2 ° and 30 °, stereoregularity was determined. Glass transition temperature (Tg) Measured by TMA in a compression mode. Flexural strength, flexural modulus, and Izod strength: Determined in accordance with JIS K-6911. The Izod strength was measured with a notch.

Fracture toughness (K _IC ) Measured according to ASTM D 5045. Water absorption rate Take out a test piece of 20 mm x 20 mm x 2 mm from the cured molded product, put it in a high-pressure steam environment tester, and continue the test until the weight of the test piece becomes constant at 121 ° C and 2 atm. The increase in weight of the test piece was expressed as a percentage.

(Synthesis Reference Example 1) (Synthesis of 4,4'-dihydroxybiphenyldiglycidyl ether) In a 5 ml three-necked flask equipped with a stirrer and a thermometer, 300 g of 4,4-dihydroxybiphenyl was added.
(1.6 mol), 4441 g of epichlorohydrin (48
Mol) and 3.0 g of tetramethylammonium chloride were added and subjected to an addition reaction under heating and reflux for 2 hours. Next, the content was cooled to 60 ° C., and a moisture removal device was installed.
134.4 g (3.2 mol) of sodium hydroxide was added,
Reaction temperature 55-60 ° C, degree of reduced pressure 100-150 mmHg
The azeotropic removal of the water generated in the above was continuously performed, and the ring closure reaction was performed while returning the epichlorohydrin layer of the distillate to the reaction system. The point at which the generated water reached 57.6 ml was taken as the reaction end point.

Thereafter, filtration under reduced pressure and washing with water were repeated, and residual epichlorohydrin was recovered by distillation under reduced pressure.
The crude glycidyl compound thus obtained was recrystallized from methyl ethyl ketone to give glycidyl compound A (melting point 1
65 ° C., epoxy equivalent 152) was obtained. The glycidyl compound A is represented by the formula (I) wherein A is a group represented by the formula (II) or (II)
In I), n had a basic skeleton of about 0.02.

(Synthesis Example 2) 100 parts of glycidyl compound A and 6.1 parts of 4,4'-dihydroxybiphenyl were added to a separable flask, and 25 mmol / LN at 120 ° C.
1.8 ml of an aOH methanol solution was added and reacted at 180 ° C. for 3 hours to obtain an epoxy resin 1 (melting point 210 ° C.). In the epoxy resin 1, A in the formula (I) is represented by the formula (I)
In I) or (III), n had a basic skeleton of about 0.25.

Synthesis Example 3 An epoxy resin 2 was obtained in the same manner as in Synthesis Example 2 except that 18.4 parts of 4,4'-dihydroxybiphenyl was used (melting point: 240 ° C.). In the epoxy resin 2, A in the formula (I) is represented by the formula (II) or (II)
In I), n had a basic skeleton of about 0.89.

Synthesis Example 4 An epoxy resin 3 was obtained in the same manner as in Synthesis Example 2 except that 30.7 parts of 4,4'-dihydroxybiphenyl was used and the reaction temperature was changed to 220 ° C. (melting point: 270 ° C.) ). The epoxy resin 3 had a basic skeleton in which A in the formula (I) was the formula (II) or (III) and n was approximately 2.05. When the epoxy resins 1 to 3 were analyzed by mass spectrometry, all of the unreacted components 4,
The residual amount of 4'-dihydroxybiphenyl was 5% or less based on the initial amount. When the epoxy resins 1 to 3 were analyzed by an X-ray diffraction method, it was found that all were crystalline.

(Example 1) 100 parts of epoxy resin 1
The test tube containing (melting point 210 ° C.) is immersed in an oil bath at 230 ° C. to melt the epoxy resin, and 34.8 parts of diaminodiphenylsulfone (DDS) is added. DD
When S was dissolved and the inside of the system became uniform, it was rapidly cooled using liquid nitrogen, and the obtained solid was pulverized with a mill to obtain a uniform mixture of powders. The above powder was added to a silicone rubber mold, and a curing reaction was performed at 180 ° C. for 5 hours and at 200 ° C. for 17 hours using pressure molding to obtain a cured product. Table 1 shows the physical properties of the obtained cured product.

(Example 2) 100 parts of epoxy resin 2
The test tube containing (melting point 240 ° C.) is immersed in an oil bath at 250 ° C. to melt the epoxy resin, and 24.2 parts of diaminodiphenylsulfone (DDS) is added. DD
When S was dissolved and the inside of the system became uniform, it was rapidly cooled using liquid nitrogen, and the obtained solid was pulverized with a mill to obtain a uniform mixture of powders. The above powder was added to a silicone rubber mold, and a curing reaction was performed at 180 ° C. for 5 hours and at 200 ° C. for 17 hours using pressure molding to obtain a cured product. Table 1 shows the physical properties of the obtained cured product.

Example 3 100 parts of epoxy resin 3
The test tube containing (melting point 270 ° C.) is immersed in an oil bath at 280 ° C. to melt the epoxy resin, and 15.6 parts of diaminodiphenylsulfone (DDS) is added. DD
When S was dissolved and the inside of the system became uniform, it was rapidly cooled using liquid nitrogen, and the obtained solid was pulverized with a mill to obtain a uniform mixture of powders. The above powder was added to a silicone rubber mold, and a curing reaction was performed at 200 ° C. for 24 hours using pressure molding to obtain a cured product. Table 1 shows the physical properties of the obtained cured product.

Comparative Example 1 100 parts of epoxy resin 1
The test tube containing (melting point 210 ° C.) was immersed in an oil bath at 230 ° C. to melt the epoxy resin, and 34.8 parts of diaminodiphenylsulfone (DDS) was added.
For 15 minutes, and after confirming that the inside of the system was gelled, a curing reaction was further performed at 200 ° C. for 17 hours to obtain a cured product. Table 1 shows the physical properties of the obtained cured product.

[0055]

As is clear from Table 1, the epoxy resin obtained by the curing method of the present invention has a plurality of glass transition points, none of which is obtained by the curing method not according to the present invention. shows a higher value than the object
Thus, there is an effect of having excellent heat resistance and toughness . In addition, it shows excellent properties in toughness, impact resistance, and also moisture resistance evaluated by water absorption.

Comparative Example 3 100 parts of epoxy resin 3
The test tube containing (melting point 270 ° C.) was immersed in an oil bath at 280 ° C. to melt the epoxy resin, and 15.6 parts of diaminodiphenylsulfone (DDS) was added thereto.
For 2 minutes, and after confirming that the inside of the system was gelled, a curing reaction was further performed at 200 ° C. for 17 hours to obtain a cured product. Table 1 shows the physical properties of the obtained cured product.

[0057]

[Table 1]

[0058]

As is clear from Table 1, the epoxy resin obtained by the curing method of the present invention has a plurality of glass transition points, none of which is obtained by the curing method not according to the present invention. It shows a higher value than the product. In addition, it shows excellent properties in toughness, impact resistance, and also moisture resistance evaluated by water absorption.

Continuation of the front page (51) Int.Cl. ⁶ identification code FI B29K 63:00 B29L 7:00 (58) Field surveyed (Int.Cl. ⁶ , DB name) C08G 59/06 C08G 59/24 B29C 43 / 00 B29C 45/00 B29C 47/00

Claims (4)

(57) [Claims] (1) As an essential component, (a) a formula (1): [Wherein A is a group represented by the formula (II): And n represents an integer of 0 or more. Epoxy resin having a melting point of 170 ° C. or more and a curing agent comprising a curing agent (b) at a temperature of 150 ° C. or more and a melting point of the epoxy resin or less. Curing method. 2. In the formula (I), A represents the following formula (III): The method for curing an epoxy resin according to claim 1, wherein an epoxy resin represented by the following formula is used. 3. An essential component comprising: (a) Formula (1): [Wherein A is a group represented by the formula (II): Alternatively, formula (III): And n represents an integer of 0 or more. ] Represented by
(B) a curing agent consisting of an epoxy resin having a
A birefringent thermosetting resin composition . 4. An essential component comprising: (a) Formula (1): [Wherein A is a group represented by the formula (II): Alternatively, formula (III): And n represents an integer of 0 or more. ], A birefringent epoxy resin-cured injection-molded product, extruded product, or compression obtained by curing a thermosetting resin composition comprising an epoxy resin having a melting point of 170 ° C or higher and a curing agent (b). Molded product or film.