JP2012219223A - Epoxy resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition capable of obtaining a cured product excellent in impact resistance.SOLUTION: The epoxy resin composition includes: one or more epoxy resins (A); a rubber modified epoxy resin (B) obtained by reacting an epoxy resin having an epoxy equivalent of 220-400 g/eq with acrylonitrile-butadiene rubber whose both terminals are provided with either a carboxyl terminal or an amino group or the both; and one or more curing agents (C).

Description

  The present invention relates to an epoxy resin composition that is excellent in impact resistance and can be used as a structural adhesive for automobiles, vehicles and the like.

  An epoxy resin composition containing an epoxy resin is excellent in workability and excellent electrical properties, heat resistance, adhesion, moisture resistance (water resistance), moldability, and the like of the cured product. Therefore, conventionally, epoxy resin compositions have been applied to various different substrates in the fields of electrical / electronic parts, automobile parts, electrical equipment, fiber reinforced plastics (FRP), sports equipment, structural materials, paints, etc. Widely used as an adhesive for bonding.

  The epoxy resin of the epoxy resin composition used for such an adhesive is fragile and easily breaks when subjected to an impact. Therefore, conventionally, adding an elastomer to an epoxy resin is said to be effective for toughening the epoxy resin composition. For example, an adduct obtained by adding butadiene-acrylonitrile rubber (carboxyl-terminated butadiene-nitrile: CTBN) having carboxyl groups at both ends to an epoxy resin as an elastomer is used as a rubber-modified epoxy resin. (For example, see Patent Documents 1 to 3).

  Patent Document 1 describes a structural adhesive using a prepolymer containing an acrylonitrile-butadiene copolymer, an epoxy resin, and a bisphenol compound.

  Patent Document 2 describes a one-component epoxy adhesive for automobile structure using a mixture containing an epoxy resin and a urethane-modified epoxy resin and / or an acrylonitrile-butadiene-modified epoxy resin.

  Patent Document 3 describes an epoxy resin composition containing a liquid epoxy resin containing an epoxy resin and a rubber-modified epoxy resin obtained by reacting a carboxyl group-containing rubbery polymer.

Japanese Patent Laid-Open No. 4-185686 JP 59-196376 JP 59-115322 A

  Here, when the epoxy resin composition is used as a structural adhesive for automobiles and the like, improvements are being made to improve adhesive properties such as the peel strength of the structural adhesive, and it has a higher peel strength. There is a need for epoxy resin compositions that provide structural adhesives.

  An object of this invention is to provide the epoxy resin composition which can obtain the hardened | cured material excellent in impact resistance in view of the said problem.

The present invention includes the following (1) to (5).
(1) one or more epoxy resins (A);
A rubber-modified epoxy resin (B) obtained by reacting an epoxy resin having an epoxy equivalent of 220 g / eq or more and 400 g / eq or less with an acrylonitrile-butadiene rubber having either or both of a carboxyl terminal and an amino group at both ends; ,
One or more curing agents (C);
An epoxy resin composition comprising:
(2) The acrylonitrile content in the acrylonitrile-butadiene rubber having either one or both of a carboxyl terminal and an amino group at both terminals of the rubber-modified epoxy resin (B) is 20% or more. Epoxy resin composition.
(3) The above, wherein the one or more urethane prepolymer end isocyanates include a urethane resin (D) blocked with at least one of ε-polycaprolactam, oximes, and pyrazoles. The epoxy resin composition as described in (1) or (2).
(4) The urethane prepolymer of the urethane resin (D) is one selected from a bisphenol A compound, one or more polyol compounds selected from polytetramethylene glycol and polycarbonate polyol, hexamethylene diisocyanate, and isophorone diisocyanate. The epoxy resin composition as described in (3) above, wherein the epoxy resin composition is obtained by reacting with an isocyanate compound higher than that.
(5) The content of the bisphenol A in the urethane resin (D) is such that the molar ratio ([polyol-OH] / [BisA-OH]) of the number of moles of hydroxyl groups of the polyol and the number of moles of hydroxyl groups of bisphenol A. The epoxy resin composition according to the above (3) or (4), which is 1 / 0.1 or more and 1 / 3.0 or less.
(6) The content of the urethane resin (D) is 10 to 80 parts by mass with respect to 100 parts by mass of the epoxy resin (A), according to any one of (3) to (5) above. Epoxy resin composition.

  According to the present invention, there is an effect that a cured product having excellent impact resistance can be obtained.

  The present invention will be described in detail below. The present invention is not limited by the following modes for carrying out the invention (hereinafter referred to as embodiments). In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the constituent elements disclosed in the following embodiments can be appropriately combined.

  The epoxy resin composition according to the present embodiment (hereinafter referred to as “the composition according to the present embodiment”) includes one or more epoxy resins (A) and an epoxy equivalent of 220 g / eq or more and 400 g / eq or less. A rubber-modified epoxy resin (B) obtained by reacting an epoxy resin with acrylonitrile-butadiene rubber having either or both of a carboxyl terminal and an amino group at both ends, and one or more curing agents (C And an epoxy resin composition.

<Epoxy resin (A)>
The epoxy resin (A) can be used without any particular limitation as long as it is a compound having two or more epoxy groups in the molecule. Examples of the epoxy resin (A) include epoxy compounds having a bisphenyl group such as bisphenol A type, bisphenol F type, brominated bisphenol A type, hydrogenated bisphenol A type, bisphenol S type, bisphenol AF type, and biphenyl type. , Polyalkylene glycol type, alkylene glycol type epoxy compound, epoxy compound having naphthalene ring, bifunctional glycidyl ether type epoxy resin such as epoxy compound having fluorene group; phenol novolac type, orthocresol novolak type, trishydroxyphenyl Multifunctional glycidyl ether type epoxy resin such as methane type, tetraphenylolethane type; glycidyl ester type epoxy resin of synthetic fatty acid such as dimer acid; N, N, N ′, N′-teto Aromatic epoxy resins having a glycidylamino group such as glycidyldiaminodiphenylmethane (TGDDM), tetraglycidyl-m-xylylenediamine, triglycidyl-p-aminophenol, N, N-diglycidylaniline; having a tricyclodecane ring An epoxy compound (for example, an epoxy compound obtained by a production method in which epichlorohydrin is reacted after polymerizing cresols or phenols such as dicyclopentadiene and m-cresol) can be used. An epoxy resin (A) can be used individually or in combination of 2 types or more, respectively.

  The epoxy resin (A) is preferably selected from the group consisting of a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, and a urethane-modified epoxy resin. This is because it is easy to obtain a composition having a storage elastic modulus after curing of 1.0 GPa or less at −20 ° C. and 0.2 to 0.7 GPa at 80 ° C.

(Bisphenol A type epoxy resin)
The bisphenol A type epoxy resin preferably has an epoxy equivalent in the range of 180 g / eq to 300 g / eq. A bisphenol A type epoxy resin can be used individually by 1 type or in combination of 2 or more types. Specific examples of the bisphenol A type epoxy resin include, for example, jER series (827, 828, 834, etc.) manufactured by Japan Epoxy Resin, Epiklon series (840, 850, etc.) manufactured by DIC, Adeka Resin EP- manufactured by ADEKA It can be used by appropriately selecting from 4100 series or the like.

(Bisphenol F type epoxy resin)
The bisphenol F-type epoxy resin preferably has an epoxy equivalent in the range of 150 g / eq to 200 g / eq. A bisphenol F type epoxy resin can be used individually by 1 type or in combination of 2 or more types. Specific examples of the bisphenol F type epoxy resin include, for example, jER series (806, 807, etc.) manufactured by Japan Epoxy Resin, Epiklon series (830, 835, etc.) manufactured by DIC, and Adeka Resin EP-4900 series manufactured by ADEKA. It can be used by appropriately selecting from the above.

(Urethane-modified epoxy resin)
The structure of the urethane-modified epoxy resin is not particularly limited as long as it is a resin having a urethane bond and two or more epoxy groups in the molecule. Urethane-modified epoxy resins can be used alone or in combination of two or more. Specifically, as the urethane-modified epoxy resin, for example, it is appropriately selected from the Mitsui Chemicals Epogee Series (803, 802-30CX, 820-40CX, 834, etc.), the ADEKA Resin EPU Series, etc. be able to.

<Rubber-modified epoxy resin (B)>
The rubber-modified epoxy resin (B) is an epoxy resin having two or more epoxy groups in the molecule and having a skeleton made of rubber. Examples of the rubber forming the skeleton include polybutadiene, acrylonitrile butadiene rubber (NBR), and acrylonitrile-butadiene rubber having one or both of a carboxyl terminal and an amino group at the terminal. Acrylonitrile-butadiene rubber having either one or both of a carboxyl end and an amino group at the terminal is a butadiene-acrylonitrile rubber having a carboxyl group at both ends (carboxyl-terminated butadiene-nitrile: CTBN)), butadiene-acrylonitrile rubber having amino groups at both ends (amino-terminated butadiene nitrile rubber (ATBN)), butadiene-acrylonitrile rubber having carboxyl groups and amino groups at both ends ( Carboxyl-terminated and amino-terminated polybutadiene-acrylonitrile rubbers). In the present embodiment, the rubber-modified epoxy resin (B) can be used alone or in combination of two or more of CTBN, ATBN, carboxyl-terminated and amino-terminated polybutadiene-acrylonitrile rubbers.

  The rubber-modified epoxy resin (B) included in the present embodiment is an acrylonitrile-butadiene rubber having an epoxy resin having an epoxy equivalent of 220 g / eq or more and 400 g / eq or less, and one or both of a carboxyl terminal and an amino group at the terminal. It is obtained by reacting. In this embodiment, an epoxy resin having an epoxy equivalent of 220 g / eq or more and 400 g / eq or less is used as a semi-solid epoxy resin. Epoxy resins are classified into liquid epoxy resins, solid epoxy resins, and semisolid epoxy resins. These classifications are classified according to, for example, the epoxy equivalent of the epoxy resin. When the epoxy resin is classified according to the epoxy equivalent, for example, an epoxy resin having an epoxy equivalent smaller than 200 g / eq is a liquid epoxy resin, and an epoxy resin having an epoxy equivalent of 200 g / eq or more and 400 g / eq or less is a half. An epoxy resin having an epoxy equivalent greater than 400 is a solid epoxy resin. In the present embodiment, an epoxy resin having an epoxy equivalent of 220 g / eq or more and 400 g / eq or less contained in the rubber-modified epoxy resin (B) is used as a semi-solid epoxy resin or semi-solid epoxy resin close to liquid.

  The method for producing the rubber-modified epoxy resin (B) is not particularly limited. For example, it can be produced by reacting an epoxy resin with acrylonitrile-butadiene rubber having either one or both of a carboxyl terminal and an amino group at the terminal.

  The epoxy resin used in producing the rubber-modified epoxy resin (B) is not particularly limited as long as the epoxy equivalent is 200 g / eq or more and 400 g / eq or less.

  The epoxy equivalent of the epoxy resin is 220 g / eq or more and 400 g / eq or less, preferably 220 g / eq or more and 350 g / eq or less, more preferably 250 g / eq or more and 300 g / eq. By setting the epoxy equivalent of the epoxy resin within the above range, an epoxy resin having an epoxy equivalent in a predetermined range is obtained by reacting with acrylonitrile-butadiene rubber having either one or both of a carboxyl end and an amino group at both ends. The epoxy resin composition containing the rubber-modified epoxy resin (B) to be produced can be a cured product excellent in viscosity, adhesiveness, and impact resistance.

  The content of acrylonitrile in the acrylonitrile-butadiene rubber having either one or both of a carboxyl terminal and an amino group at the terminal contained in the rubber-modified epoxy resin (B) is preferably 15% or more and 35% or less, More preferably, it is 20% or more and 30% or less. When there is little content of acrylonitrile, compatibility with an epoxy resin will fall and it will isolate | separate. Moreover, since there is too good compatibility when there is too much, there exists a possibility that the heat resistance of hardened | cured material may fall.

  In the present embodiment, the epoxy equivalent of the rubber-modified epoxy resin (B) and the amount added thereof indicate the amount as “the rubber-modified epoxy resin containing the epoxy” because of the excess epoxy resin used during the production. And

  The epoxy resin composition generally includes a rubber-modified epoxy resin or a urethane resin as an elastomer, but the urethane resin (D) is a highly polar component. Adhesiveness decreases with respect to the steel plate etc. which have. On the other hand, the rubber-modified epoxy resin (B) has a property that is easily compatible with the oil component. Since the composition which concerns on this embodiment contains a rubber modified epoxy resin (B) other than an epoxy resin (A), it can maintain the stable adhesiveness also to the steel plate etc. which have an oil surface.

<Curing agent (C)>
The hardening | curing agent (C) contained in the composition of this invention is not specifically limited, What is normally used as a hardening | curing agent of an epoxy resin can be used. Examples of the curing agent include dicyandiamide, 4,4-diaminodiphenylsulfone, imidazole derivatives such as 2-n-heptadecylimidazole, isophthalic acid dihydrazide, N, N-dialkylurea derivatives, N, N-dialkylthiourea derivatives, Acid anhydrides such as tetrahydrophthalic anhydride, isophoronediamine, m-phenylenediamine, N-aminoethylpiperazine, melamine, guanamine, boron trifluoride complex compound, trisdimethylaminomethylphenol, polythiol and the like can be used.

  The polythiol is not particularly limited as long as it is a compound having two or more mercapto groups. Examples of the thiol having two mercapto groups include alkylene dithiols such as ethanedithiol, propanedithiol, butanedithiol, pentanedithiol, and hexanedithiol; benzenedithiol, toluene-3,4-dithiol, and 3,6-dichloro-1 , 2-benzenedithiol, 1,5-naphthalenedithiol, aromatic dithiols such as 4,4'-thiobisbenzenethiol; dithiols of aromatic hydrocarbon compounds such as benzenedimethanethiol; 2-di- heterocyclic compounds such as n-butylamino-4,6-dimercapto-s-triazine; 2-mercapto-3-thiahexane-1,6-dithiol, 5,5-bis (mercaptomethyl) -3,7-dithianonane -1,9-dithiol, 5- (2-mercap) Ethyl) -3,7 Jichianonan -1,9-thia compounds such as dithiol; dimercaptopropanol, compounds having a hydroxy group such as dithioerythritol, and the like.

  Examples of the thiol having three or more mercapto groups include trithioglycerin, 1,3,5-triazine-2,4,6-trithiol (trimercapto-triazine), trimethylolpropane tristhioglycolate, and trimethylolpropane. Tristhiopropionate, 1,2,4-tris (mercaptomethyl) benzene, 1,3,5-tris (mercaptomethyl) benzene, 2,4,6-tris (mercaptomethyl) mesitylene, tris (mercaptomethyl) Isocyanurates, tris (3-mercaptopropyl) isocyanurate, trithiols such as 2,4,5-tris (mercaptomethyl) -1,3-dithiolane; pentaerythritol tetrakisthioglycolate, pentaerythritol tetrakisthiopropionate, , 2,4,5-tetrakis (mercaptomethyl) benzene, tetra mercaptobutanoic include tetrathiol such as pentaerythritol thiol.

  Examples of the polythiol include polythiol (for example, “QE-340M” manufactured by Toray Fine Chemical Co., Ltd.) in which a mercapto group is introduced at the end of a polyether (for example, polyoxypropylene glycol).

  You may use a hardening | curing agent (C) in combination of 2 or more types in these.

  The content of the curing agent (C) in the composition of the present invention is not particularly limited, and the optimum amount varies depending on the type of the curing agent. For example, the optimal amount for each curing agent known in the art can be preferably used. This optimum amount is described, for example, in Chapter 3 of “Review Epoxy Resin Basics” (Epoxy Resin Technical Association, published in 2003).

<Urethane resin (D)>
The urethane resin (D) is a resin containing a urethane prepolymer and bisphenol A. The urethane resin (D) is a resin in which an isocyanate at a urethane prepolymer terminal is blocked with at least one of ε-polycaprolactam, oximes, and pyrazoles. The urethane prepolymer contains bisphenol A in the skeleton of the urethane prepolymer.

[Urethane prepolymer]
A conventionally well-known thing can be used for the urethane prepolymer used for a urethane resin (D). The urethane prepolymer is obtained by, for example, reacting a polyol compound and a polyisocyanate compound so that an isocyanate group (NCO group) of the polyisocyanate compound is excessive with respect to a hydroxyl group (OH group) of the polyol compound. Product. Moreover, it is preferable that the said urethane prepolymer contains 0.5 mass% or more and 10 mass% or less of NCO groups in a molecular terminal.

(Polyol compound)
The polyol compound used in the production of the urethane prepolymer is not particularly limited as long as it has two or more hydroxyl groups. Examples of the polyol compound include polyether polyol, polycarbonate polyol, polyester polyol, other polyols, and mixed polyols thereof.

  Examples of the polyether polyol include polytetramethylene glycol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, 1,1,1-trimethylolpropane, 1,2,5-hexanetriol, 1,3- At least one polyhydric alcohol selected from butanediol, 1,4-butanediol, 4,4′-dihydroxyphenylpropane, 4,4′-dihydroxyphenylmethane, pentaerythritol, etc., and ethylene oxide, propylene oxide, butylene Polyether polyol obtained by adding at least one selected from the group consisting of oxide, styrene oxide and polyoxytetramethylene oxide; polyoxytetramethylene oxide; And the like. Specific examples of the polyether polyol include polyoxypropylene glycol, polytetramethylene ether glycol, polyethylene glycol, polyoxypropylene triol and the like.

  The polycarbonate polyol is not particularly limited as long as it has a carbonate bond (—O—CO—O—) and two or more hydroxy groups. For example, what can be obtained by transesterification with the alkoxy group of a dialkyl carbonate and the group which remove | excluded the hydrogen atom from the hydroxyl group of a polyol compound is mentioned.

The method for producing the polycarbonate polyol is not particularly limited. For example, it can be performed according to a conventionally known method. Examples of the polycarbonate polyol include HO [(CH ₂ ) ₆ —O—C (═O) —O] _m (CH ₂ ) ₆ —OH (m is an integer of 2 to 50). Specifically, a polycarbonate polyol obtainable from a diol body of a chain aliphatic hydrocarbon compound having 2 to 10 carbon atoms such as ethylene glycol and 1,6-hexanediol, and 3 to 10 carbon atoms such as cyclohexanediol. And polycarbonate polyols obtainable from diols of alicyclic hydrocarbon compounds. Of these, polycarbonate polyols derived from diols of aliphatic hydrocarbon compounds having 2 to 10 carbon atoms are preferred from the viewpoints of adhesion, wettability, and availability of raw materials. The polycarbonate polyol preferably has a weight average molecular weight of 1000 or more from the viewpoint of adhesion and wettability. The polycarbonate polyol is more preferably derived from a diol body of a chain aliphatic hydrocarbon compound having 6 or more carbon atoms and having a molecular weight of 1000 or more from the viewpoint of adhesion and wettability. Polycarbonate polyols can be used alone or in combination of two or more.

  Specific examples of the polyester polyol include ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol, glycerin, 1,1,1-trimethylolpropane, and other low molecular weight polyols. At least one selected from the group consisting of: at least one selected from the group consisting of glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, terephthalic acid, isophthalic acid or other low molecular carboxylic acids and oligomeric acids Condensation polymers with seeds; ring-opening polymers such as propionlactone, valerolactone, caprolactone; and the like.

  Specific examples of other polyols include polymer polyols; polybutadiene polyols; hydrogenated polybutadiene polyols; acrylic polyols, etc .; ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butanediol, pentanediol, and hexanediol. Low molecular weight polyols such as, and the like.

  Among the polyols described above, polyether polyols having a number average molecular weight of 1000 to 15000, particularly 1000 to 10,000 are preferable from the viewpoint of glass transition temperature and physical properties after curing.

  Such polyol compounds can be used alone or in combination of two or more. Of these, polytetramethylene glycol and polycarbonate polyol are particularly preferable. Polytetramethylene glycol and polycarbonate polyol can improve the compatibility with the epoxy resin (A), and the cured product comprising the composition according to this embodiment obtained by using this urethane prepolymer has high strength and elongation. Can have.

(Polyisocyanate compound)
The polyisocyanate compound used when producing the urethane prepolymer is not particularly limited as long as it has two or more isocyanate groups in the molecule.

Specific examples of the polyisocyanate compound include TDI (for example, 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI)), MDI ( For example, 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI)), 1,4-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate, xylylene diene Isocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), tolidine diisocyanate (TODI), 1,5-naphthalene diisocyanate (NDI), aromatic polyisocyanates such as triphenylmethane triisocyanate Aliphatic diisocyanates such as ethylene diisocyanate, propylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, norbornane diisocyanate (NBDI); transcyclohexane-1,4- Cycloaliphatic polyisocyanates such as diisocyanates, isophorone diisocyanate (IPDI), bis (isocyanate methyl) cyclohexane (H ₆ XDI), dicyclohexylmethane diisocyanate (H ₁₂ MDI); these carbodiimide modified polyisocyanates; these isocyanurate modified Polyisocyanate; aryl aliphatic poly, such as xylylene diisocyanate Isocyanate and hydrogenated compounds; and the like. Such polyisocyanate compounds can be used alone or in combination of two or more.

  Of these, the polyisocyanate compound is particularly preferably hexamethylene diisocyanate or isophorone diisocyanate.

  The urethane prepolymer used for the urethane resin (D) can be produced by reacting the above-described polyol compound with an excess polyisocyanate compound. The mixing ratio of the polyol compound and the polyisocyanate compound is preferably such that the molar ratio (NCO / OH) of the isocyanate group in the polyisocyanate compound to the hydroxy group in the polyol compound is 1.2 to 2.5. More preferably, it is .5 to 2.0. If it is this range, the viscosity of a urethane prepolymer and the physical property of hardened | cured material will become a suitable range. Moreover, manufacture of the said urethane prepolymer can be performed by the method similar to a normal urethane prepolymer. For example, a urethane prepolymer can be obtained by heating and stirring the polyol compound and polyisocyanate compound having the above-mentioned mixing ratio at 50 to 100 ° C. Moreover, if necessary, a urethanization catalyst such as an organic tin compound, organic bismuth, or amine can be used.

  In this embodiment, the urethane resin (D) is one or more polyol compounds selected from polytetramethylene glycol and polycarbonate polyol, and one or more isocyanate compounds selected from hexamethylene diisocyanate and isophorone diisocyanate. It is preferable that it is obtained by making it react.

  The amount of the polyisocyanate compound and the polyol compound in producing the urethane prepolymer is preferably such that the NCO group / OH group (equivalent ratio) is 1.2 to 2.5, and 1.5 to 2 Is more preferably 0.0. When the equivalence ratio is within such a range, the viscosity of the obtained urethane prepolymer becomes appropriate, and the remaining amount of the unreacted polyisocyanate compound in the urethane prepolymer can be reduced.

  The manufacturing method of a urethane prepolymer is not specifically limited, For example, it can manufacture by heating and stirring the polyol compound and polyisocyanate compound of the above-mentioned equivalent ratio at 50 to 130 degreeC. Moreover, if necessary, for example, a urethanization catalyst such as an organic tin compound, organic bismuth, or amine can be used.

  Such urethane prepolymers can be used alone or in combination of two or more.

  The average functionality (number of isocyanate groups) of the urethane prepolymer is preferably 2.2 to 3.0 per molecule, more preferably 2.4 to 2.8, and 0.4% or more in terms of mass%. Preferably, it is 0.5% or more. The urethane prepolymer has a mass average molecular weight of preferably 2,000 to 1,000,000, more preferably 2,000 to 70,000. Within this range, the resulting composition of the present invention is excellent in viscosity, adhesiveness, and properties after curing (eg, hardness, modulus).

  In the urethane resin (D), the isocyanate at the end of the urethane prepolymer is blocked using at least one of ε-polycaprolactam, oximes, and pyrazoles as a blocking agent. As the blocking agent, ε-polycaprolactam is preferable among ε-polycaprolactam, oximes, and pyrazoles.

  The isocyanate at the end of the urethane prepolymer is blocked with at least one blocking agent of ε-polycaprolactam, oximes, and pyrazoles, so that when the composition is cured, the blocking agent is removed and the isocyanate becomes an epoxy resin. It is incorporated into (A) or a curing agent and crosslinked.

  In the present embodiment, the content of bisphenol A in the urethane resin (D) is the molar ratio between the number of hydroxyl groups of the polyol compound and the number of moles of hydroxyl groups of bisphenol A ([polyol-OH] / [BisA-OH]). ) Is preferably from 1 / 0.1 to 1 / 3.0, more preferably from 1 / 0.5 to 1 / 2.5, and from 1 / 1.0 to 1 / 2.0. More preferably, it is as follows. When there is little content of bisphenol A, familiarity with an epoxy resin (A) will worsen, and the hardened | cured material obtained from the composition which concerns on this embodiment will become weak easily. If the content of bisphenol A is too large, the amount of blocking agent such as ε-polycaprolactam increases, and the blocking agent cannot be removed by heating, or the blocking agent remains in the composition. Strength cannot be obtained and physical properties are deteriorated. Therefore, by setting the content of bisphenol A in the urethane resin (D) within the above range, the compatibility with the epoxy resin (A) can be improved, and curing obtained from the composition according to the present embodiment. The strength of the object can be maintained and the impact resistance can be improved. In addition, the impact resistance can be stably maintained even for a plated steel plate or the like.

  The urethane resin (D) is preferably contained in an amount of 10 to 80 parts by weight, more preferably 30 to 70 parts by weight, and still more preferably 40 parts by weight with respect to 100 parts by weight of the epoxy resin (A). Part to 70 parts by mass. By setting the content of the urethane resin (D) within the above range, the effect of the urethane resin (D) can be maintained.

  As described above, the composition according to this embodiment includes the epoxy resin (A), an epoxy resin having an epoxy equivalent of 220 g / eq or more and 400 g / eq or less, and either one or both of a carboxyl terminal and an amino group at both terminals. It is an epoxy resin composition containing a rubber-modified epoxy resin (B) obtained by reacting acrylonitrile-butadiene rubber with a curing agent (C). As an epoxy resin contained in the rubber-modified epoxy resin (B), an epoxy equivalent of 220 g / eq or more and 400 g / eq or less, whose form is liquid, semi-solid or semi-solid epoxy resin, this epoxy equivalent Is used as a rubber-modified epoxy resin (B), which is obtained by reacting an acrylonitrile-butadiene rubber having either or both of a carboxyl terminus and an amino group at both ends with an epoxy resin having a predetermined range. Thereby, while being able to maintain the intensity | strength of the hardened | cured material obtained from the composition which concerns on this embodiment, sufficient elongation can be provided and it is stable with respect to the steel plate which has not plated, the plated steel plate, etc. Thus, impact resistance can be improved and stable adhesiveness can be maintained.

  In addition to the epoxy resin (A), the urethane resin (D), and the curing agent (C) described above, the composition according to this embodiment contains additives as long as the object of the present invention is not impaired as necessary. Can be included. Examples of additives include plasticizers, fillers, reactive diluents, curing catalysts, thixotropic agents, silane coupling agents, pigments, dyes, anti-aging agents, antioxidants, antistatic agents, flame retardants, Examples include a drying oil, an adhesion-imparting agent, a dispersant, a dehydrating agent, an ultraviolet absorber, and a solvent. Two or more of these may be contained.

  The manufacturing method of the composition which concerns on this embodiment is not specifically limited, For example, it can manufacture by a conventionally well-known method. For example, the epoxy resin (A), the urethane resin (D), and the curing agent (C) and, if necessary, other components such as a curing accelerator can be obtained by uniformly mixing at room temperature.

  Since the composition according to this embodiment is excellent in impact resistance, the composition according to this embodiment can be preferably used as a structural adhesive. Here, the “structural adhesive” is a highly reliable adhesive (JIS K6800) with little deterioration in adhesive properties even when a large load is applied for a long time. For example, it can be used as an adhesive for structural members in the fields of automobiles, vehicles (bullet trains, trains), civil engineering, architecture, electronics, aircraft, and the space industry. The composition according to this embodiment can be suitably used as an adhesive for automobile structures such as automobiles and vehicles (bullet trains, trains) and an adhesive for vehicle structures.

  In addition to the structural adhesive, the composition according to this embodiment can also be used as an adhesive for general office work, medical use, carbon fiber, electronic material, and the like. As adhesives for electronic materials, interlayer adhesives for multilayer substrates such as build-up substrates, optical component bonding adhesives, optical disk bonding adhesives, printed wiring board mounting adhesives, die bonding adhesives, underfills And adhesives for semiconductors such as BGA reinforcing underfill, anisotropic conductive film (ACF), and anisotropic conductive paste (ACP).

  Moreover, the composition according to the present embodiment can be used as an adhesive, as well as an article for general use in which a thermosetting resin such as an epoxy resin is used. For example, paints, coating agents, molding materials (including sheets, films, FRP, etc.), insulating materials (including printed circuit boards, electric wire coatings, etc.), sealants, flat panel display sealing agents, fiber binding agents, etc. Can be mentioned.

  Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.

<Production of rubber-modified epoxy resins (B) 1 to (B) 4>
[Production of rubber-modified epoxy resin (B) 1 (epoxy resin (epoxy equivalent: 250 g / eq), carboxyl-terminated acrylonitrile-butadiene rubber (CTBN) (acrylonitrile (AN) content: 26%))]
Bisphenol A type epoxy resin (trade name: “JER834”, manufactured by Japan Epoxy Resin, epoxy equivalent: 250 g / eq) 100 parts by mass, CTBN (trade name: “Hycar1300 × 13”, acrylonitrile content: 26%, PIT 50 parts by mass of Japan) and 1 part by mass of triphenylphosphine (manufactured by Tokyo Chemical Industry Co., Ltd.) as a catalyst were mixed and reacted at 110 ° C. for 2 hours to obtain rubber-modified epoxy resin (B) 1.

[Production of rubber-modified epoxy resin (B) 2 (epoxy resin (epoxy equivalent: 250 g / eq), CTBN (AN content: 18%))]
As CTBN, except that “Hycar1300 × 13” was changed to “Hycar1300 × 8” (AN content: 18%, manufactured by PIT Japan), the same as the case of producing the rubber-modified epoxy resin (B) 1 described above Synthesized.

[Production of rubber-modified epoxy resin (B) 3 (epoxy resin (epoxy equivalent: 190 g / eq), CTBN (AN content: 26%))]
The above rubber-modified epoxy resin (B) 1 is replaced with bisphenol A type epoxy resin (trade name: “EP4100E”, manufactured by ADEKA, epoxy equivalent: 190 g / eq) instead of bisphenol A type epoxy resin. Synthesis was performed in the same manner as in the production.

[Production of rubber-modified epoxy resin (B) 4 (epoxy resin (epoxy equivalent: 450 g / eq), CTBN (AN content: 26%))]
The rubber-modified epoxy resin (B) except that the bisphenol A type epoxy resin (trade name: “Epicoat 1001”, manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent: 450 g / eq) was used instead of the bisphenol A type epoxy resin. ) 1 was synthesized in the same manner as in the production of 1.

  Table 1 shows the form of each epoxy resin of the rubber-modified epoxy resins (B) 1 to (B) 4, the epoxy equivalent, and the AN content of CTBN.

<Production of urethane resins (D) 1 to (D) 3>
[Production of Urethane Resin (D) 1 ([Polyol-OH] / [BisA-OH] = 1 / 2.5, Blocking Agent: ε-Caprolactam)]
100 parts by mass of polytetramethylene glycol (PTMG-2000, manufactured by Mitsubishi Chemical Corporation), 31.1 parts by mass of 2,2-bis (4-hydroxyphenyl) propane (manufactured by Tokyo Chemical Industry Co., Ltd.), and trimethylolpropane (Tokyo Chemical Industry) 0.45 parts by mass) was dehydrated at 110 ° C. under reduced pressure for 5 hours. Thereafter, the mixture was cooled to 60 ° C., 48.3 parts by mass of hexamethylene diisocyanate (50M-HDI, manufactured by Asahi Kasei Chemicals) and 5 ppm of dibutyl syndilaurate (manufactured by Tokyo Chemical Industry) were added, and 90 ° C. in a nitrogen atmosphere. The reaction was performed for 3 hours. After the reaction, the reaction mixture was cooled to 60 ° C., 21.7 parts by mass of ε-caprolactam (manufactured by Tokyo Chemical Industry Co., Ltd.) was added as a blocking agent, and the mixture was reacted at 90 ° C. for 1 hour. When FT-IR measurement was performed after the reaction, a peak at 2265 cm ⁻¹ attributed to the isocyanate group was not observed. As a result, urethane resin (D) 1 having a [polyol-OH] / [BisA-OH] ratio of 1 / 2.5 was obtained.

[Production of Urethane Resin (D) 2 ([Polyol-OH] / [BisA-OH] = 1 / 1.5, Blocking Agent: ε-Caprolactam)]
The urethane described above except that 2,2-bis (4-hydroxyphenyl) propane was changed to 17.4 parts by mass, hexamethylene diisocyanate was changed to 33.3 parts by mass, and ε-caprolactam was changed to 15.0 parts by mass. The resin (D) 1 was synthesized in the same manner as in the production. As a result, a urethane resin (D) 2 having a [polyol-OH] / [BisA-OH] ratio of 1 / 1.5 was obtained.

[Production of Urethane Resin (D) 3 ([Polyol-OH] / [BisA-OH] = 1 / 1.0, Blocking Agent: ε-Caprolactam)]
The urethane described above except that 2,2-bis (4-hydroxyphenyl) propane was changed to 11.7 parts by mass, hexamethylene diisocyanate was changed to 27.0 parts by mass, and ε-caprolactam was changed to 12.1 parts by mass. The resin (D) 1 was synthesized in the same manner as in the production. Thereby, urethane resin (D) 3 having a [polyol-OH] / [BisA-OH] ratio of 1 / 1.0 was obtained.

  Table 1 shows each [polyol-OH] / [BisA-OH] of the urethane resins (D) 1 to (D) 3 and the blocking agent used to block the isocyanate at the terminal of the urethane prepolymer.

<Preparation of epoxy resin composition>
Each component shown in Table 1 was blended in the addition amount (parts by mass) shown in the same table, and these were uniformly mixed to prepare each composition shown in Table 1. Table 1 shows the addition amount (parts by mass) of each component in each Example and Comparative Example.

<Evaluation of impact resistance>
The epoxy resin composition obtained as described above was stirred for 5 minutes under reduced pressure. A non-plated steel plate (steel plate) or a galvanized steel plate is used as an adherend, and an epoxy resin composition is applied to the surface of the adherend so that the thickness of the adhesive is about 0.15 mm. The adhesive was cured for a minute to obtain a test piece. In the impact peel strength test, the impact peel strength (N / mm) was measured according to the wedge impact method of ISO 11343. The adherend used was 0.8 mm × 25 mm × 100 mm. The test results of impact peel strength are shown in Table 1.

Each component other than the rubber-modified epoxy resins (B) 1 to (B) 4 and the urethane resins (D) 1 to (D) 3 shown in Table 1 is as follows.
Epoxy resin (A): Epoxy resin (trade name: “JER834”, manufactured by Japan Epoxy Resin Co., Ltd.)
Curing agent (C): Dicyandiamide (trade name: “DICY15”, manufactured by Japan Epoxy Resin Co., Ltd.)
Curing accelerator: 3,4-dichlorophenyl-1,1-dimethylurea (“DCMU”, manufactured by Hodogaya Chemical Co., Ltd.)
Thixotropic agent: Aerosil (“RY-200S”, manufactured by Nippon Aerosil Co., Ltd. (added by 3 parts by mass with respect to the total resin content))
-Adhesion imparting agent: Epoxy silane ("KBM-403", manufactured by Shin-Etsu Chemical Co., Ltd. (1 part by mass added to the total resin content))

  As is clear from the results shown in Table 1, in Comparative Examples 1 and 3, the impact peel strength could not be measured for any adherend of a steel plate or a galvannealed steel plate. Moreover, although the comparative example 2 was able to measure impact peel strength with respect to a steel plate, it is as low as 20 N / mm or less, and cannot measure impact peel strength with respect to a galvannealed steel plate. It was. A cured product obtained by curing the resin composition when none of the rubber-modified epoxy resins (B) 1 to (B) 4 and the urethane resins (D) 1 to (D) 3 are contained as components of the resin composition Can not be said to have sufficient impact resistance (see Comparative Example 1). In addition, when a rubber-modified epoxy resin (B) 3 produced using an epoxy resin having an epoxy equivalent of about 190 g / eq is used, the cured product obtained by curing the resin composition has a certain resistance to the steel plate. Although it can have impact properties, its impact resistance is low, and it can be said that it cannot have impact resistance for galvannealed steel sheets (see Comparative Example 2). Moreover, when the rubber-modified epoxy resin (B) 4 produced using an epoxy resin having an epoxy equivalent of about 450 g / eq is used, the cured product obtained by curing the resin composition has sufficient impact resistance. It can be said that this is not possible (see Comparative Example 3).

  In contrast, in Examples 1 to 5, the impact peel strength was 20 N / mm or more for both adherends of steel sheets and galvannealed steel sheets, and had impact resistance. A cured product obtained by curing a resin composition containing a predetermined amount using rubber-modified epoxy resins (B) 1 and (B) 2 prepared using an epoxy resin having an epoxy equivalent of about 250 g / eq has sufficient resistance. It can be said that it is possible to have impact properties (see Examples 1 to 5). Further, when Examples 1 and 2 were compared, Example 1 was higher in impact peel strength than Example 2 for both adherends of steel sheets and galvannealed hot-dip steel sheets. Therefore, it can be said that the greater the AN content of CTBN, the better the impact peel strength and the better the impact resistance.

  Further, when Examples 1 and 3 to 5 were compared, Examples 3 to 5 had higher impact peel strength than Example 1 for both adherends of steel sheets and galvannealed steel sheets. This is considered that when the resin composition is cured, the isocyanate group can react with the epoxy resin (A) by removing the ε-polycaprolactam that blocked the isocyanate group at the terminal of the urethane prepolymer. . Therefore, it can be said that the impact peeling strength with respect to the adherend was higher in Examples 3 to 5 than in Example 1. Therefore, as a component contained in the epoxy resin composition, the isocyanate group at the end of the urethane prepolymer is blocked with ε-polycaprolactam, and the urethane resin (D) containing bisphenol A is included in the skeleton of the urethane prepolymer. It can be said that the peel strength is increased and the impact resistance is excellent.

  Therefore, the cured product obtained from the epoxy resin composition of the present invention has a stable and improved impact peel strength for both adherends of steel plates and galvannealed steel plates, and has excellent impact resistance. I understood. Furthermore, it has a stable and high impact resistance against a coated plate such as a structural member of an automobile or a vehicle, such as a plated steel plate. Therefore, since the cured product obtained from the epoxy resin composition of the present invention has stable and excellent impact resistance, a highly reliable adhesive, particularly a structural adhesive can be obtained.

Claims (6)

One or more epoxy resins (A);
A rubber-modified epoxy resin (B) obtained by reacting an epoxy resin having an epoxy equivalent of 220 g / eq or more and 400 g / eq or less with an acrylonitrile-butadiene rubber having either or both of a carboxyl terminal and an amino group at both ends; ,
One or more curing agents (C);
An epoxy resin composition comprising:   The epoxy resin composition according to claim 1, wherein the acrylonitrile content in the acrylonitrile-butadiene rubber having either one or both of a carboxyl terminal and an amino group at both terminals of the rubber-modified epoxy resin (B) is 20% or more. object.   The one or more urethane prepolymer-terminated isocyanates comprise a urethane resin (D) blocked with at least one of ε-polycaprolactam, oximes, and pyrazoles. 2. The epoxy resin composition according to 2.   The urethane prepolymer of the urethane resin (D) is a bisphenol A compound, one or more polyol compounds selected from polytetramethylene glycol and polycarbonate polyol, and one or more selected from hexamethylene diisocyanate and isophorone diisocyanate. The epoxy resin composition according to claim 3, wherein the epoxy resin composition is obtained by reacting with an isocyanate compound.   The content of the bisphenol A in the urethane resin (D) is such that the molar ratio ([polyol-OH] / [BisA-OH]) of the number of moles of hydroxyl groups of the polyol to the number of moles of hydroxyl groups of bisphenol A is 1/0. The epoxy resin composition according to claim 3 or 4, which is 1 or more and 1 / 3.0 or less.   6. The epoxy resin composition according to claim 3, wherein the content of the urethane resin (D) is 10 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the epoxy resin (A).