JP2005146128A - Epoxy resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin composition providing a cured product having high flexibility, capable of forming a thin film, and having excellent heat resistance and adhesiveness. <P>SOLUTION: A novolak-type resin of phenols, having 130-200°C softening point is used as a curing agent in a bromine-containing bisphenol A-type epoxy resin having ≥350 g/eq epoxy equivalent. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an epoxy resin composition that provides a cured product having excellent heat resistance and has sufficient flexibility when formed into a film.

Epoxy resins are generally cured with various curing agents, resulting in cured products with excellent mechanical properties, water resistance, chemical resistance, heat resistance, electrical properties, etc., adhesives, paints, laminates, moldings It is used in a wide range of fields such as materials and casting materials. Conventionally, since high reliability is required in the electric / electronic parts field, ortho-cresol novolac type epoxy resins have been widely used. Further, acid anhydrides and amine compounds are known as curing agents for epoxy resins, but phenol novolac is often used from the viewpoint of reliability such as heat resistance in the field of electric and electronic parts.
However, although the combination of the ortho cresol novolac type epoxy resin and the phenol novolac as described above is excellent in heat resistance, the cured product is rigid and lacks flexibility. In recent years, electrical and electronic components are not only used for conventional large packages and glass fiber-based substrates, but are also applied to varnish on polyimide, PET (polyethylene glycol terephthalate) films, and metal foils. Sheet-like moldings to be removed have been developed. In such a case, the resin used is required to have sufficient flexibility. A high molecular weight polyhydroxy polyether resin is often used as a material suitable for such applications (Patent Document 1). However, this polyhydroxy polyether resin is substantially a thermoplastic resin, and has a remarkable heat resistance. Inferior.

JP 2003-119370 A

  An object of this invention is to provide the epoxy resin composition which gives the hardened | cured material excellent in flexibility and heat resistance.

  In view of the actual situation, the present inventors have completed the present invention as a result of earnestly researching an epoxy resin composition that gives a cured product excellent in heat resistance and has sufficient flexibility even when formed into a sheet shape. I came to let you.

  That is, the present invention provides (1) (a) the following formula (1)

(Wherein m is a positive number and represents an average value; R represents a hydrogen atom or a bromine atom), the bromine content is 15 to 50% by weight, and the epoxy equivalent is 350 g / eq or more. And (b) the following formula (2)

(Wherein n represents the number of repetitions, R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms) and a novolac resin having a softening point of 130 to 200 ° C. Epoxy resin composition,
(2) The epoxy resin composition according to the above (1), which contains a curing accelerator,
(3) A varnish containing the epoxy resin composition and the solvent according to (1) or (2) above,
(4) a sheet having a layer of the epoxy resin composition according to the above (1) or (2) on both sides or one side of a planar support;
(5) The sheet according to (4), wherein the planar support is a polyimide film or a metal foil,
(6) The sheet according to (4), wherein the planar support is a release film,
Is to provide.

  The cured product of the epoxy resin composition of the present invention has sufficient flexibility even when molded into a thin film, and since the cured product is excellent in heat resistance, it is a molding material, casting material, laminated material. It is extremely useful for a wide range of applications such as paints, adhesives, and resists.

  In the present invention, the epoxy resin as the component (a) has an epoxy equivalent of 350 g / eq or more, preferably 360 g / eq or more, usually 6000 g / eq or less, preferably 5000 g / eq or less, particularly preferably 370 to 2000 g / eq. eq. The epoxy equivalent can be measured according to the description of JIS K7236. A commercially available epoxy resin can be used. Specific examples include AER8011, AER8018 (both manufactured by Asahi Kasei Epoxy Corporation). In formula (1), some or all of R may be bromine atoms, but the proportion of bromine atoms in the epoxy resin is usually preferably 15 to 50% by weight.

  The novolac resin represented by the formula (2) and having a softening point of 130 to 200 ° C. can be obtained by reacting phenols and formaldehyde in a specific ratio in the presence of an acid catalyst.

  Examples of phenols include phenol, cresol, propylphenol, and tertiary butylphenol. Among them, cresol is preferable, and o-cresol is particularly preferable. Phenols may be used alone or in combination.

  The formaldehyde may be a formalin aqueous solution or a polymer, paraformaldehyde. The charging ratio of formaldehyde is usually 1: 0.1 to 1: 0.95, preferably 1: 0.15 to 0.9, relative to the number of moles of phenol. As a preparation method, in the case of a formalin aqueous solution, a method of dropping in the system is preferable, and in the case of paraformaldehyde, a method of gradually adding a predetermined amount while paying attention to heat generation is preferable.

  Examples of the acid catalyst include oxalic acid, hydrochloric acid, sulfuric acid, paratoluenesulfonic acid and the like. The usage-amount of an acid catalyst is 0.01-10 weight part normally with respect to 100 weight part of phenols, Preferably it is 0.05-5 weight part.

  The reaction temperature is usually 50 to 180 ° C, preferably 60 to 150 ° C. The reaction time may be determined by using GPC (gel permeation chromatography) or the like as the end point where the molecular weight is not changed. In practice, it is usually 1 to 20 hours, preferably 1.5 to 15 hours. It is preferable to remove the water produced during the reaction using a fractionating tube or the like in order to rapidly advance the reaction.

  In the above reaction, an organic solvent may be used or no solvent may be used. When an organic solvent is used, methyl isobutyl ketone, toluene, methyl ethyl ketone and the like are preferable. The amount of the organic solvent is usually 10 to 300% by weight, preferably 20 to 200% by weight, based on the total weight of the charged phenols and formalin. After completion of the reaction, the acid catalyst is removed by washing with water. After washing with water, unreacted phenols and solvent are removed under reduced pressure by heating using an evaporator or the like. The phenol novolac resin thus obtained is represented by the formula (2). In formula (2), n represents the number of repetitions, but an average value of about 10 to 30 is usually used. Moreover, although the softening point of the compound of Formula (2) is 130-200 degreeC, 160-180 degreeC is preferable. When the softening point is lower than 130 ° C., the film forming ability is deteriorated and the film cannot be formed at all. If it exceeds 200 ° C., the fluidity at the time of curing will deteriorate, and the adhesiveness will deteriorate accordingly.

  In the epoxy resin composition of the present invention, the epoxy resin represented by the formula (1) can be used alone or in combination with other epoxy resins. When used together, the proportion of the epoxy resin of formula (1) or formula (2) in the total epoxy resin is preferably 30% by weight or more, particularly preferably 40% by weight or more.

  Specific examples of other epoxy resins that can be used in combination with the epoxy resin represented by the formula (1) include novolac type epoxy resins, bisphenol F type epoxy resins, biphenyl type epoxy resins, triphenylmethane type epoxy resins, dicyclo Pentadiene / phenol polycondensation type epoxy resin, biphenyl novolac type epoxy resin and the like can be mentioned, but these may be used alone or in combination of two or more.

  In the epoxy resin composition of the present invention, the novolac resin represented by the formula (2) acts as a curing agent for the epoxy resin and can be used alone or in combination with other curing agents. When used in combination, the proportion of the novolak resin represented by the formula (2) in the total curing agent is preferably 30% by weight or more, particularly preferably 40% by weight or more.

Examples of other curing agents that can be used in combination with the novolak resin represented by the formula (2) include amine compounds, acid anhydride compounds, amide compounds, and phenol compounds. Specific examples of curing agents that can be used include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, dicyandiamide, polyamide resin synthesized from linolenic acid and ethylenediamine, phthalic anhydride, triethylene anhydride. Merit acid, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, phenol novolac with a softening point of about 120 ° C. or less, And modified products thereof, imidazole, BF ₃ -amine complexes, guanidine derivatives and the like, but are not limited thereto. These may be used alone or in combination of two or more.

  In the epoxy resin composition of the present invention, the amount of the curing agent used is preferably 0.7 to 1.2 equivalents relative to 1 equivalent of the epoxy group of the epoxy resin. When less than 0.7 equivalent or more than 1.2 equivalent with respect to 1 equivalent of epoxy group, curing may be incomplete and good cured properties may not be obtained.

  In addition, a curing accelerator may be used in combination in the epoxy resin composition of the present invention. Specific examples of the curing accelerator that can be used include, for example, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl. Imidazoles such as -4-methyl-5-hydroxymethylimidazole, tertiary amines such as 2- (dimethylaminomethyl) phenol and 1,8-diaza-bicyclo (5,4,0) undecene-7 And phosphines such as triphenylphosphine, and metal compounds such as tin octylate. The curing accelerator is used in an amount of 0.1 to 5.0 parts by weight as needed with respect to 100 parts by weight of the total epoxy resin in the epoxy resin composition of the present invention.

  The epoxy resin composition of the present invention contains an inorganic filler as necessary. Specific examples of the inorganic filler that can be used include silica, alumina, talc and the like. The inorganic filler is used in an amount of 0 to 90% by weight in the epoxy resin composition of the present invention. Furthermore, various compounding agents such as a silane coupling agent, a release agent such as stearic acid, palmitic acid, zinc stearate, and calcium stearate, and a pigment can be added to the epoxy resin composition of the present invention.

  The epoxy resin composition of the present invention can be obtained by uniformly mixing the above components. The epoxy resin composition of the present invention can be easily made into a cured product by a method similar to a conventionally known method. For example, the epoxy resin, the curing agent, and if necessary, the curing accelerator, the inorganic filler, and the compounding agent are mixed sufficiently until uniform using an extruder, a kneader, a roll, or the like as necessary. An epoxy resin composition is obtained, and the epoxy resin composition is molded by a melt casting method, a transfer molding method, an injection molding method, a compression molding method or the like, and further cured by heating at 80 to 200 ° C. for 2 to 10 hours. You can get things.

  The varnish of the present invention is obtained by dissolving the epoxy resin composition of the present invention in a solvent. Examples of the solvent used include amide solvents such as γ-butyrolactone, N-methylpyrrolidone (NMP), N, N-dimethylformamide (DMF), N, N-dimethylacetamide, N, N-dimethylimidazolidinone and the like. , Sulfones such as tetramethylene sulfone, ether solvents such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether monoacetate, propylene glycol monobutyl ether, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone And ketone solvents such as cyclohexanone and aromatic solvents such as toluene and xylene. The solvent is used in the range where the solid content concentration in the obtained varnish is usually 10 to 80% by weight, preferably 20 to 70% by weight. In addition, the varnish of this invention can be obtained by mixing a solvent in the process of mixing each component at the time of preparing the epoxy resin composition of this invention.

  The sheet of the present invention has a predetermined thickness after drying the above varnish on a planar support by various known coating methods such as gravure coating, screen printing, metal mask, and spin coating. For example, although it is obtained by drying after coating so as to be 5 to 100 μm, which coating method is used is appropriately selected depending on the type, shape, size, and film thickness of the coating film. Examples of the planar support include various polymers such as polyimide, polyamide, polyamideimide, polyarylate, polyethylene terephthalate (PET), polybutylene terephthalate, polyetheretherketone, polyetherimide, polyetherketone, polyketone, polyethylene, and polypropylene. And / or a film made of a copolymer thereof, or a metal foil such as a copper foil, and particularly preferably a polyimide or a metal foil. Further, a sheet-like cured product can be obtained by further heating. Moreover, a varnish is apply | coated on the peeling film which consists of the said polymer film, it can dry for 5 to 20 minutes at 50-100 degreeC, a solvent is removed, and a semi-hardened thermosetting adhesive film can be obtained.

  EXAMPLES Next, the present invention will be described more specifically with reference to examples. In the following, parts are parts by weight unless otherwise specified.

Example 1
AER-8018 as an epoxy resin (epoxy resin in which all of R in formula (1) are bromine atoms; manufactured by Asahi Kasei Co., Ltd., bromine content 48 wt%, epoxy equivalent 395 g / eq, softening point 70 ° C.) 39.5 parts As a curing agent, the following formula (3)

2-phenyl-4-methyl-5 as a curing accelerator, 12.0 parts of a novolak type resin (softening point 173.2 ° C., hydroxyl group equivalent 120 g / eq, where n = 31 (average value)) A varnish of the present invention was obtained by mixing 0.32 part of hydroxymethylimidazole and 52 parts of methyl ethyl ketone as a solvent.

  The above varnish of the present invention is applied onto a PET film so that the thickness after drying is 50 μm, dried and heated at 180 ° C. for 1 hour to cure, and the PET film is removed to obtain a sheet-like sample. It was. The obtained sample did not crack even when bent, and had sufficient film forming ability. The glass transition temperature of this sample was measured by DMA (Dynamic Viscoelasticity Measuring Device) and found to be 184.3 ° C. Furthermore, the obtained varnish was apply | coated to the rough surface of the surface-treated copper foil of thickness 18 micrometers so that the thickness after drying might be 10 micrometers using an applicator. An adhesive layer obtained by drying at 100 ° C. for 10 minutes to remove the solvent is overlaid with a polyimide film having a thickness of 25 μm (Upilex 25SGA manufactured by Ube Industries Co., Ltd.) and cured at 180 ° C. for 1 hour using a hot plate press. Went. The peel strength at an angle of 90 degrees was measured and found to be 12.1 N / cm.

Claims (6)

(A) The following formula (1)

(Wherein m represents a repeating number, R represents a hydrogen atom or a bromine atom), an epoxy resin having a bromine content of 15 to 50% by weight and an epoxy equivalent of 350 g / eq or more; (B) The following formula (2)

(Wherein n represents the number of repetitions, R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms), and contains a novolac resin having a softening point of 130 to 200 ° C. An epoxy resin composition. The epoxy resin composition of Claim 1 containing a hardening accelerator. A varnish containing the epoxy resin composition according to claim 1 or 2 and a solvent. The sheet | seat which has a layer of the epoxy resin composition of Claim 1 or 2 on both surfaces or one side of a planar support body. The sheet according to claim 4, wherein the planar support is a polyimide film or a metal foil. The sheet according to claim 4, wherein the planar support is a release film.