JP7168130B1 - Urethane resin, resin composition, adhesive composition, and method for producing urethane resin - Google Patents

Abstract

[PROBLEMS] To provide a urethane resin, a resin composition, an adhesive composition, and a method for producing the urethane resin, which are excellent in flex resistance and elongation and have no stickiness, which conventional urethane resins cannot achieve. SOLUTION: A urethane resin satisfying the following (1) to (3). (1) Glass transition temperature (Tg) is 40° C. or higher (2) Weight average molecular weight (Mw) is 180,000 to 2,000,000 (3) Molecular weight distribution (Mw/Mn) is 9 to 200 (where Mn represents the number average molecular weight) [Selection] None

Description

TECHNICAL FIELD The present invention relates to a urethane resin, a resin composition, an adhesive composition, and a method for producing a urethane resin. More particularly, it relates to an adhesive composition that is excellent in tack resistance, bending resistance and elongation.

Urethane resins are excellent in flexibility, abrasion resistance, oil resistance, chemical resistance, adhesiveness, etc., and are widely used for paints, inks, adhesives, and other coating agents. In recent years, flexible printed wiring boards (hereinafter also referred to as FPCs) have been used in applications that require high heat resistance, such as wiring board materials for electronic devices that require flexibility and space saving, and substrate materials for mounting. is being used, and both heat resistance and flexibility are required.

In general, it is known to raise the glass transition temperature of resins in order to increase the heat resistance of adhesives and coating agents. A problem inferior to For example, in Patent Document 1, in a urethane adhesive composition for food packaging, a urethane adhesive composition excellent in hot water resistance is produced by incorporating a polyol having a high glass transition temperature and a polyol having a low glass transition temperature. It has been proposed (Patent Document 1).

Japanese Patent No. 3583629

By the way, in the film for manufacturing FPC, there is a case where the release film is coated with an adhesive and stored in a roll until the manufacturing process. I had a problem with it. Although it is known to solve the sticking problem by raising the glass transition temperature of the resin, raising the glass transition temperature causes the problem of flexibility. It was difficult to solve them at the same time.

An object of the present invention is to provide a urethane resin, a resin composition, an adhesive composition, and a method for producing the urethane resin, which have excellent flex resistance and elongation and are free from sticking, which could not be achieved with conventional urethane resins. That is.

As a result of intensive studies by the present inventors in order to solve the above problems, it has been found that a urethane resin having a specific glass transition temperature, a large average molecular weight, and a wide molecular weight distribution has the flexibility and sticking property. The inventors have found that both of the problems can be solved, and have completed the present invention.

That is, the present invention is a urethane resin that satisfies the following (1) to (3).
(1) Glass transition temperature (Tg) is 40° C. or higher
(2) Weight average molecular weight (Mw) is 180,000 to 2,000,000 (3) Molecular weight distribution (Mw/Mn) is 9 to 200 (where Mn represents number average molecular weight)

The urethane resin contains a radically polymerizable double bond derived from a compound (C) having a functional group reactive with a hydroxyl group or an isocyanate group and a radically polymerizable double bond in the same molecule, and the compound (C). It is preferable to have at least one of the polymers of as a constituent element.

The urethane resin preferably has a carboxyl group and an acid value of 50 to 500 eq/t.

The urethane resin can have a polyol (A) as a structural unit, and the polyol (A) contains at least one polyol selected from the group consisting of polyester polyols, polyether polyols, polycarbonate polyols and polyolefin polyols. It is preferable that the glass transition temperature of the polyol (A) is -30 to 30°C.

The urethane resin can be a resin composition containing a cross-linking agent. An epoxy resin or an isocyanate resin can be preferably used as the cross-linking agent, and the resin composition can be used as an adhesive composition.

As a method for producing the urethane resin, a polyol (A), a polyisocyanate compound (B), and a functional group having reactivity with the polyol (A) or the polyisocyanate compound (B) and a radically polymerizable double bond can be produced by radical polymerization after preparing a urethane polymer having a compound (C) having in the same molecule as a constituent element.

According to the present invention, it is possible to provide a urethane resin, a resin composition and an adhesive composition which are excellent in flexibility and do not stick.

The urethane resin of the present invention is a urethane resin that satisfies the following (1) to (3).
(1) Glass transition temperature (Tg) is 40° C. or higher (2) Weight average molecular weight (Mw) is 180,000 to 2,000,000 (3) Molecular weight distribution (Mw/Mn) is 9 to 200

<Requirement (1)>
The glass transition temperature (Tg) of the urethane resin of the present invention must be 40°C or higher. A Tg of 40° C. or higher can provide necessary flexibility and heat resistance. It is more preferably 45° C. or higher, still more preferably 50° C. or higher. Although the upper limit is not particularly limited, it is practically 60°C or less. The glass transition temperature is measured by the method described in Examples.

<Requirement (2)>
The weight average molecular weight (Mw) of the urethane resin of the present invention is generally 150,000 to 2,000,000. It is preferably 180,000 or more, more preferably 200,000 or more, and still more preferably 220,000 or more. Also, it is preferably 1,800,000 or less, more preferably 1,700,000 or less, and still more preferably 1,600,000 or less. By setting the weight average molecular weight within the above range, it is possible to obtain a urethane resin that does not stick, that is, has excellent tack resistance and flexibility. The weight average molecular weight is measured by the method described in Examples.

<Requirement (3)>
The molecular weight distribution (Mw/Mn) of the urethane resin of the present invention must be 9-200. More preferably 10 or more, still more preferably 15 or more, and most preferably 20 or more. Also, it is more preferably 180 or less, still more preferably 170 or less, and most preferably 160 or less. When the molecular weight distribution is within the above range, it is possible to obtain a urethane resin having a high molecular weight and excellent solvent solubility. The reason for this is not clear, but due to the wide molecular weight distribution, high and low molecular weight components coexist, and the low molecular weight component acts as a compatibilizer for the high molecular weight component, resulting in excellent tack resistance with high molecular weight. It is considered to be a urethane resin with excellent solvent solubility and good processability while having The molecular weight distribution (Mw/Mn) is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), and is measured by the method described in Examples in the same manner as the polymerization average molecular weight.

The urethane resin of the present invention is not particularly limited as a structural unit, and one composed of a structural unit containing a polyol (A) and a polyisocyanate compound (B) can be used.

<Polyol (A)>
Polyol (A) (hereinafter also referred to as component (A)) that can constitute the urethane resin of the present invention is not particularly limited, and polyether glycol, polyester glycol, polyether ester glycol, polycarbonate glycol, polyolefin glycol, silicone polyol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, polytetramethylene glycol, 1,5-pentanediol, 1 ,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 2-ethyl-1,3-hexane glycol, 2,2,4-trimethyl-1,3-pentanediol, 3,3 - aliphatic glycols such as dimethylolheptane, 1,9-nonanediol and 2-methyl-1,8-octanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, tricyclodecanediol, Alicyclic glycols such as tricyclodecanedimethylol, spiroglycol, hydrogenated bisphenol A, ethylene oxide adducts and propylene oxide adducts of hydrogenated bisphenol A, paraxylene glycol, metaxylene glycol, orthoxylene glycol, 1,4 - Ethylene oxide or propylene oxide to two phenolic hydroxyl groups of bisphenols, such as phenylene glycol, ethylene oxide adduct of 1,4-phenylene glycol, bisphenol A, ethylene oxide adduct and propylene oxide adduct of bisphenol A and aromatic glycols such as glycols obtained by adding 1 to several moles of each. These can be used alone or in combination of two or more.

Examples of polyether glycols include those obtained by ring-opening polymerization of cyclic ethers, such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Polyester glycols include dicarboxylic acids (succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, etc.) or their anhydrides and low molecular weight diols (ethylene glycol, diethylene glycol, triethylene glycol, Propylene glycol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, polytetramethylene glycol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl -1,5-pentanediol, neopentyl glycol, 2-ethyl-1,3-hexane glycol, 2,2,4-trimethyl-1,3-pentanediol, 3,3-dimethylolheptane, 1,9- nonanediol, 2-methyl-1,8-octanediol, cyclohexanedimethanol, bishydroxyethoxybenzene, para-xylene glycol, meta-xylene glycol, ortho-xylene glycol, 1,4-phenylene glycol, etc.). Examples include polyethylene adipate, polypropylene adipate, polybutylene adipate, polyhexamethylene adipate, polybutylene sebacate and the like, and those obtained by ring-opening polymerization of lactones to low molecular weight diols, such as polycaprolactone and polymethylvalerolactone. be done. Examples of polyether ester glycol include polyester glycol obtained by ring-opening polymerization of cyclic ether, polycondensation of polyether glycol and dicarboxylic acid, such as poly(polytetramethylene ether) adipate. Examples of polycarbonate glycols include polybutylene carbonate, polyhexamethylene carbonate, poly(3-methyl-1,5-pentylene) carbonate and the like obtained by deglycol or dealcoholization from low molecular weight diol and alkylene carbonate or dialkyl carbonate. Examples of polyolefin polyols include polybutadiene polyol, hydrogenated polybutadiene polyol, and polyisoprene polyol. Silicon polyols include polydimethylsiloxane polyols and the like.

Component (A) used in the present invention preferably has a glass transition temperature of −30° C. or higher. It is more preferably -25°C or higher, still more preferably -20°C or higher. Also, it is preferably 30° C. or lower, more preferably 25° C. or lower, and still more preferably 20° C. or lower. By setting the glass transition temperature within the above range, the tack resistance and flexibility of the urethane resin are improved. In addition, when the component (A) is composed of a plurality of components, the glass transition temperature of the component (A) is calculated by weighted average from the glass transition temperature of each component and the mass ratio of each component.

<Polyisocyanate compound (B)>
The polyisocyanate compound (B) (hereinafter also referred to as component (B)) that can constitute the urethane resin of the present invention is not particularly limited as long as it is a polyisocyanate compound, such as aromatic polyisocyanate, aliphatic polyisocyanate or alicyclic group polyisocyanates. Examples of aromatic polyisocyanates include, but are not limited to, diphenylmethane-2,4'-diisocyanate, or 3,2'- or 3,3'- or 4,2'- or 4,3'- or 5, 2'- or 5,3'- or 6,2'- or 6,3'-dimethyldiphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4 ,3′- or 5,2′- or 5,3′- or 6,2′- or 6,3′-diethyldiphenylmethane-2,4′-diisocyanate, 3,2′- or 3,3′- or 4,2'- or 4,3'- or 5,2'- or 5,3'- or 6,2'- or 6,3'-dimethoxydiphenylmethane-2,4'-diisocyanate, diphenylmethane-4,4 '-diisocyanate, diphenylmethane-3,3'-diisocyanate, diphenylmethane-3,4'-diisocyanate, diphenyl ether-4,4'-diisocyanate, benzophenone-4,4'-diisocyanate, diphenylsulfone-4,4'-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, naphthalene-2,6-diisocyanate, 4,4′-[2,2-bis(4- phenoxyphenyl)propane] diisocyanate, 3,3′ or 2,2′-dimethylbiphenyl-4,4′-diisocyanate, 3,3′- or 2,2′-diethylbiphenyl-4,4′-diisocyanate, 3, 3'-dimethoxybiphenyl-4,4'-diisocyanate, 3,3'-diethoxybiphenyl-4,4'-diisocyanate and the like. Considering heat resistance, adhesion, solubility, cost, etc., diphenylmethane-4,4'-diisocyanate, tolylene-2,4-diisocyanate, m-xylylene diisocyanate, 3,3'- or 2,2'-dimethylbiphenyl-4,4'-diisocyanate is preferred. These can be used alone or in combination of two or more.

The charge ratio of the polyisocyanate compound (B) is such that the molar ratio of isocyanate group/hydroxyl group (NCO/OH) is 1.01 to 5 from the hydroxyl group of the polyol (A) and the isocyanate group of the component (B). and more preferably 1.01 to 2. If the charge ratio is less than 1.01, the resin becomes brittle due to its low molecular weight. In addition, when the component (D) described later is contained, the hydroxyl group is calculated as the total amount of the hydroxyl groups of the component (A) and the component (D).

<Compound (C) Having a Functional Group Reactive with a Hydroxyl Group or an Isocyanate Group and a Radically Polymerizable Double Bond in the Same Molecule>
The urethane resin of the present invention comprises a compound (C) (hereinafter also referred to as component (C)) having a functional group reactive with a hydroxyl group or an isocyanate group and a radically polymerizable double bond in the same molecule as a structural unit. You may have it as Examples of such component (C) include 2-isocyanatoethyl methacrylate (manufactured by Showa Denko Co., Ltd., Karenz MOI), 2-isocyanatoethyl acrylate (manufactured by Showa Denko Co., Ltd., Karenz AOI), 2-(2-methacryloyloxyethyl Oxy) ethyl isocyanate (manufactured by Showa Denko Co., Ltd., Karenz MOI-EG), 1,1-(bisacryloyloxymethyl) ethyl isocyanate (manufactured by Showa Denko Co., Ltd., Karenz BEI), 2-hydroxyethyl methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., Light Ester HO-250 (N)), 2-hydroxypropyl methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., Light Ester HOP (N)), 2-hydroxyethyl acrylate (manufactured by Kyoeisha Chemical Co., Ltd., Light Ester HOP-A (N)), 2 -Hydroxybutyl methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., light ester HOB (N)) and the like. From the viewpoint of radical reactivity, the radically polymerizable double bond of component (C) is preferably positioned at the terminal of the molecule of component (C).

The content of component (C) in the urethane resin is preferably 1 to 20 parts by weight, more preferably 2 to 10 parts by weight, per 100 parts by weight of component (B). If the content of component (C) is less than 1 part by weight, the molecular weight is not sufficiently increased by radical polymerization.

<Polyol (D) Having One or More Carboxyl Groups>
The urethane resin of the present invention may have a polyol (D) having one or more carboxyl groups (hereinafter also referred to as component (D)) as a structural unit. Examples of such component (D) include 3,5-dihydroxybenzoic acid, 2,2-bis(hydroxymethyl)propionic acid, 2,2-bis(hydroxymethyl)butanoic acid, 2,2-bis( 2-hydroxyethyl)propionic acid, 2,2-bis(3-hydroxypropyl)propionic acid, bis(hydroxymethyl)acetic acid, bis(4-hydroxyphenyl)acetic acid, 2,2-bis(hydroxymethyl)butyric acid, 4 , 4-bis(4-hydroxyphenyl)pentanoic acid, tartaric acid and the like.

The urethane resin of the present invention preferably has an acid value of 50-500 eq/t. It is more preferably 80 eq/t or more, still more preferably 100 eq/t or more. Also, it is preferably 450 eq/t or less, more preferably 400 eq/t or less. By setting the acid value within the above range, it can be used for a cross-linking reaction with a cross-linking agent, which will be described later. If the acid value is less than 50 eq/t, the strength of the cured coating film cannot be maintained when cured with a cross-linking agent, and as a result, the elongation decreases and cracks tend to occur in the flexibility test. On the other hand, if the acid value is more than 500 eq/t, the cured coating film will have a large number of cross-linking points, and the flexibility will be lost.

The urethane resin of the present invention can be produced, for example, by the following method. That is, first, a urethane polymer containing the component (A), component (B) and component (C) as structural units is produced by a known prepolymerization method. Then, a radical polymerization initiator is added to radically polymerize the radically polymerizable double bond derived from the component (C), whereby a urethane resin having a high molecular weight and a wide molecular weight distribution can be produced. According to this method, even high-molecular-weight resins, which have conventionally been difficult to dissolve, can be produced in the form of a solution. The urethane polymer may further have component (D) as a structural unit.

As the polymerization solvent in the above method, any solvent having low reactivity with isocyanate can be used, and for example, a solvent that does not contain a basic compound such as amine is preferred. Examples of such solvents include toluene, xylene, ethylbenzene, nitrobenzene, cyclohexane, isophorone, diethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, dipropylene glycol methyl ether acetate, diethylene glycol ethyl. ether acetate, methyl methoxypropionate, ethyl methoxypropionate, methyl ethoxypropionate, ethyl ethoxypropionate, ethyl acetate, n-butyl acetate, isoamyl acetate, ethyl lactate, acetone, methyl ethyl ketone, cyclohexanone, N,N-dimethylformamide, Examples include N,N-dimethylacetamide, N-methylpyrrolidone, N-ethylpyrrolidone, γ-butyrolactone, dimethylsulfoxide, chloroform and methylene chloride.

A normal urethanization reaction catalyst is used as a catalyst for producing a urethane resin. For example, tin-based compounds such as dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dioctoate, stannous octoate, iron-based compounds such as iron acetylacetonate and ferric chloride, triethylamine, lutidine, picoline, undecene, triethylenediamine (1 ,4-diazabicyclo[2,2,2]octane) and DBU (1,8-diazabicyclo[5,4,0]-7-undecene).

Examples of radical polymerization initiators include azobisisobutyronitrile, azobisdimethylvaleronitrile, azobiscyclohexanenitrile, 1,1′-azobis(1-acetoxy-1-phenylethane), dimethyl 2,2′- azo compounds such as azobisisobutyrate and 4,4'-azobis-4-cyanovaleric acid; benzoyl peroxide, lauroyl peroxide, acetyl peroxide, caprylyl peroxide, 2,4-dichlorobenzoyl peroxide, isobutyl peroxide, acetylcyclohexylsulfonyl peroxide, t-butyl peroxypivalate, t-butyl peroxyneodecanoate, t-butyl peroxyneoheptanoate, t-butyl peroxy-2-ethylhexanoate, 1,1-di(t-butylperoxy)cyclohexane, 1,1-di(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-di(t-hexylperoxy)-3 , 3,5-trimethylcyclohexane, diisopropylperoxydicarbonate, diisobutylperoxydicarbonate, di-sec-butylperoxydicarbonate, di-n-butylperoxydicarbonate, bis(2-ethylhexyl)peroxydicarbonate , bis(4-t-butylcyclohexyl)peroxydicarbonate, t-amylperoxy-2-ethylhexanoate, 1,1,3,3-tetramethylbutylperoxy-ethylhexanoate, 1,1 , 2-trimethylpropylperoxy-2-ethylhexanoate, t-butylperoxyisopropylmonocarbonate, t-amylperoxyisopropylmonocarbonate, t-butylperoxy-2-ethylhexylcarbonate, t-butylperoxyallyl carbonate, t-butylperoxyisopropyl carbonate, 1,1,3,3-tetramethylbutylperoxyisopropyl monocarbonate, 1,1,2-trimethylpropylperoxyisopropyl monocarbonate, 1,1,3,3-tetra Organic peroxides such as methyl butyl peroxyisononaate, 1,1,2-trimethylpropyl peroxy-isononaate, t-butyl peroxybenzoate, lauroyl peroxide and the like.

The type of radical polymerization initiator can be selected according to solvent solubility and polymerization temperature. For example, although not particularly limited in the present invention, the radical polymerization initiator preferably has a half-life of 10 minutes or more and 3 hours or less at the polymerization temperature. The amount of the radical polymerization initiator to be used may be adjusted according to the target polymerization rate and reaction conditions. 15% by weight is preferred. These radical polymerization initiators may be used singly or in combination of two or more. The polymerization temperature is preferably 10-180°C, more preferably 30-150°C. The resin solid content during polymerization is preferably 5 to 95% by weight, more preferably 20 to 60% by weight.

In addition to components (A)-(D) above, and radical polymerization initiators, any other suitable components such as chain transfer agents, rubbery polymers such as butadiene and styrene-butadiene rubbers (SBR), heat stabilizers , an ultraviolet absorber, or the like may be used. Here, the chain transfer agent can be selected according to the type of urethane resin to be produced and the raw material monomer to be used. For example, n-octylmercaptan and n-dodecylmercaptan are preferred as chain transfer agents, although they are not particularly limited in the present invention. The heat stabilizer can also be used to suppress thermal decomposition of the urethane resin to be produced and to prevent thermal polymerization of radically polymerizable double bonds during the urethanization reaction. Examples of heat stabilizers include phenolic compounds such as methylhydroquinone, t-butylcatechol and chloranil, amines such as diphenylpicrylhydrazine and diphenylamine, and high-valent metal salts such as ferric chloride and cupric chloride. be done. The ultraviolet absorber is used to suppress deterioration of the produced urethane resin due to ultraviolet rays.

<Crosslinking agent>
In order to improve the flexibility of the urethane resin of the present invention, various cross-linking agents and, if necessary, other resins may be added to obtain a cross-linked coating film. Examples of cross-linking agents include epoxy resins, isocyanate resins, silane compounds, and the like.

The epoxy resin is not particularly limited as long as it has two or more epoxy groups per molecule. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type, or hydrogenated products thereof, phenol novolak type epoxy resin, glycidyl ether type epoxy resin such as cresol novolak type epoxy resin, glycidyl hexahydrophthalate Glycidyl ester epoxy resins such as esters and dimer acid glycidyl esters, linear aliphatic epoxy resins such as epoxidized polybutadiene and epoxidized soybean oil, and the like can be used. Further, the epoxy resin may be modified with, for example, silicone, urethane, polyimide, polyamide, or the like, and may contain a sulfur atom, a nitrogen atom, or the like in the molecular skeleton. Examples of these commercially available products include bisphenol A type epoxy resins such as jER828 and 1001 (trade names) manufactured by Mitsubishi Chemical Corporation, and hydrogenated bisphenol A such as ST-2004 and ST-2007 (trade names) manufactured by Nippon Steel & Sumikin Chemicals. type epoxy resin, EXA-9726 manufactured by DIC Corporation; DEN-438 (trade name) manufactured by Dow Chemical Co., Ltd.; HP7200 (trade name), HP7200H (trade name), etc., manufactured by DIC Corporation; YDCN-700 series (trade name); ) manufactured by EOCN-125S, 103S, 104S and other cresol novolac type epoxy resins, Nippon Steel & Sumikin Chemical Co., Ltd. manufactured by trade name YD-171 and other flexible epoxy resins, Mitsubishi Chemical Corporation trade name Epon 1031S, trade name Araldite 0163 manufactured by Ciba Specialty Chemicals Co., Ltd., trade name Denacol EX-611, EX-614, EX-622, EX-512, EX-521, EX- manufactured by Nagase ChemteX Co., Ltd. 421, EX-411, EX-321 and other polyfunctional epoxy resins, trade name Epicoat 604 manufactured by Mitsubishi Chemical Corporation, trade name YH-434 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., Ciba Specialty Chemicals Co., Ltd. Heterocycle-containing epoxy resins such as Araldite PT810 (trade name) manufactured by Daicel Chemical Industries, Ltd.; Celoxide 2021, EHPE3150 (trade names) manufactured by Daicel Chemical Industries, Ltd.; Bisphenol S type epoxy resin such as Epiclon EXA-1514, triglycidyl isocyanurate such as TEPIC manufactured by Nissan Chemical Industries, Ltd., bixylenol type epoxy resin such as YX-4000 manufactured by Mitsubishi Chemical Corporation, Mitsubishi Chemical Bisphenol type epoxy resins such as YL-6056 (trade name) manufactured by Co., Ltd. may be used. In addition, these may be used alone, or may be used in combination.

Examples of the isocyanate resin include p-phenylene diisocyanate, naphthalene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, lysine diisocyanate, and these. Examples include trimers, water adducts, and low-molecular-weight polyol adducts thereof.

Examples of the silane compound include acetoxysilane, alkoxysilane, ketoximesilane, aminosilane and aminoxysilane.

The amount of the cross-linking agent to be added is preferably such that the amount of reactive functional groups in the cross-linking agent is about 1 to 2 times the acid value of the urethane resin. The crosslinked coating film is formed by applying a mixture containing a crosslinker and heating at 40 to 200° C. for several seconds to several hours.

EXAMPLES The present invention will be specifically described below with reference to Examples.

<Glass transition temperature>
Using a differential scanning calorimeter "DSC220" manufactured by Seiko Electronics Industry Co., Ltd., 5 mg of the measurement sample was placed in an aluminum pan, the lid was pressed and sealed, held at 250 ° C. for 5 minutes, and then rapidly cooled with liquid nitrogen. Then, the temperature was measured from -150°C to 250°C at a heating rate of 20°C/min. From the obtained curve, the temperature at the intersection of the extended line of the baseline below the glass transition temperature and the tangent line showing the maximum slope at the transition portion was defined as the glass transition temperature.

<Weight average molecular weight, number average molecular weight and molecular weight distribution>
Measured under the following conditions using gel permeation chromatography (GPC), and using analysis software (Lab Solutions (TM) manufactured by Shimadzu Corporation), the weight average molecular weight, number average molecular weight and molecular weight distribution converted to standard polystyrene. A value of (weight average molecular weight/number average molecular weight) was calculated.
Measuring device Tosoh HLC-8220
Column 2 TSKgel super HM-H and 1 SuperH 2500 connected in series Detector Differential refractive index (RI) detector Solution preparation Using tetrahydrofuran as solvent, 0.05% by weight solution of sample Column temperature 40°C
Injection volume 20 μL
Flow rate 0.6ml/min

<Acid value>
0.2 g of a sample was dissolved in 20 ml of chloroform and titrated with 0.1 N potassium hydroxide ethanol solution using phenolphthalein as an indicator. From this titration amount, an acid value (100 eq/t=5.6 mgKOH/g) was calculated by converting the number of mg of potassium hydroxide consumed for neutralization into the amount per 1 g of resin.

(Preparation of urethane resin composition solution)
A urethane resin composition solution was prepared by dissolving the urethane resin and the cross-linking agent obtained in Examples or Comparative Examples in methyl ethyl ketone so that the total solid concentration of the urethane resin and the cross-linking agent was 20% by weight. The blending amount of the cross-linking agent was based on the acid value of the urethane resin so that the acid value (eq/t) of the urethane resin was 1.1 times the functional group equivalent (eq/t) of the cross-linking agent.
The following cross-linking agents were used.
CL-1: HP-7200 (Epoxy resin manufactured by DIC) Epoxy equivalent 3,861eq/t
CL-2: jER152 (epoxy resin manufactured by Mitsubishi Chemical Corporation) epoxy equivalent 5,747 eq/t

<Tack resistance test>
The urethane resin composition solution prepared by the above method was applied to a copper foil with an applicator of 125 μm and dried at 120° C. for 3 minutes to prepare a coating film. A polyimide film (Apical 12.5NPI manufactured by Kaneka) is placed on the dry resin, a standard weight with a load of 1 kg is placed on it, and it is left to stand in an atmosphere of 40 ° C for 3 days, then cut into width 10 mm length 50 mm After that, using a tensile tester (Autograph AG-X plus manufactured by Shimadzu Corporation), the polyimide film was peeled off in a 90° direction at a rate of 50 mm/min in an atmosphere of 40°C to measure the adhesive strength. Adhesion strength of 0.1 N/mm or less was judged to be no tack.
Evaluation ○: No tack (with tack resistance)
×: Tacky (no tack resistance)

<Tensile test>
The urethane resin composition solution prepared by the above method was applied to a Teflon (registered trademark) sheet with an applicator of 125 μm, dried at 120° C. for 3 minutes, and further cured at 150° C. for 1 hour to prepare a cured coating film. . The cured coating film was cut to a width of 10 mm and a length of 50 mm to obtain a tensile test piece. Using a tensile tester (Shimadzu Autograph AG-X plus), a tensile test was performed at 25 ° C. at a speed of 50 mm / min, and the length of the test piece when it reached breakage was measured and evaluated as follows. .
Evaluation method: Elongation (%) = 100 × (length of test piece at break - length of test piece before test) / length of test piece before test

<Flexibility test>
To the urethane resin composition solution prepared by the above method, carbon black (MHI Black #C570 manufactured by Mikuni Shiso Co., Ltd.) is added as a coloring agent so that the total amount of the urethane resin and the cross-linking agent is 100 parts by weight, and the total amount is 20 parts by weight. and methyl ethyl ketone was added so that the solid content concentration was 20% by weight to obtain a colorant mixed solution.
The resulting colorant mixed solution was applied to a copper foil with an applicator of 125 μm, dried at 120° C. for 3 minutes, and further cured at 150° C. for 1 hour to prepare a cured coating film. This coating film is bent at a bending radius of R = 0.2 mm and then returned to its original position, which is repeated 10 times. I decided.
Evaluation ○: No cracks ×: Cracks present

(Example 1)
A reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen inlet tube was charged with 45.30 g (0.149 mol) of Newpol BPE-20T (manufactured by Sanyo Chemical Industries, Ltd., polyether polyol), PTMG2000 (manufactured by Mitsubishi Chemical Corporation). , polyolefin polyol) 105.70 g (0.053 mol), 2,2-dimethylolbutanoic acid 10.57 g (0.071 mol), 4,4'-diphenylmethane diisocyanate (MDI) 63.42 g (0.253 mol) ) and 5.85 g (0.038 mol) of Karenz MOI (manufactured by Showa Denko Co., Ltd., 2-isocyanatoethyl methacrylate), and 0.063 g (0.063 g) of 1,8-diazabicyclo[5.4.0]-7-undecene as a catalyst ( 0.417 mmol) was added and dissolved in 137.5 g of cyclohexanone and 137.5 g of methyl ethyl ketone as solvents. Then, after reacting at 80° C. for 6 hours while stirring under nitrogen stream, 0.293 g (0.735 mmol) of lauroyl peroxide was added and further reacted at 80° C. for 5 hours. .85 g (0.079 mol) is added, diluted with 400.0 g of methyl ethyl ketone, and the solution temperature is cooled to room temperature to obtain a pale yellow and viscous urethane resin (PU-1) having a nonvolatile content of 25% by mass. A solution was obtained.
After dissolving 10 mg of a sample obtained by drying the resin solution in 0.6 ml of heavy DMSO, the solution was filled in an NMR tube and measured by nuclear magnetic resonance ( ¹ H-NMR). Deuterated DMSO was used as a lock solvent, and the number of accumulations was 64. Measurement was performed using an NMR apparatus AVANCE-NEO 600 (resonance frequency 600 MHz) manufactured by BRUKER. When the heavy DMSO peak was set at 2.5 ppm, it was confirmed that most of the peaks (5.5 ppm, 6.0 ppm) derived from radically polymerizable double bonds disappeared.

(Example 2)
ETERNACOLL UM90 (1/1) (manufactured by Ube Industries, polycarbonate polyol) 89.03 g (0.099 mol), G-1000 (Nippon Soda Co., Ltd., polyolefin polyol) 8.09 g (0.008 mol), PTMG2000 (Mitsubishi Chemical Co., Ltd., polyether polyol) 64.75 g (0.032 mol), 2,2-dimethylolbutanoic acid 11.33 g (0 077 mol), 51.80 g (0.207 mol) of 4,4′-diphenylmethane diisocyanate (MDI) and 4.56 g (0.029 mol) of Karenz MOI (manufactured by Showa Denko Co., Ltd., 2-isocyanatoethyl methacrylate). , 0.052 g (0.341 mmol) of 1,8-diazabicyclo[5.4.0]-7-undecene was added as a catalyst and dissolved in 137.5 g of cyclohexanone and 137.5 g of methyl ethyl ketone as solvents. Then, after reacting at 80° C. for 6 hours while stirring under a nitrogen stream, 0.205 g (0.515 mmol) of lauroyl peroxide was added and further reacted at 80° C. for 5 hours. .56 g (0.058 mol) is added, diluted with 400.0 g of methyl ethyl ketone, and the solution temperature is cooled to room temperature to obtain a pale yellow and viscous urethane resin (PU-2) having a nonvolatile content of 25% by mass. A solution was obtained. By the same NMR method as in Example 1, it was confirmed that most of the radically polymerizable double bonds had disappeared.

(Example 3)
283.29 g (0.497 mol) of pripol 2033 (manufactured by Croda Japan Co., dimer polyol) and 70% of Duranol T5652 (manufactured by Asahi Kasei Chemicals, polycarbonate polyol) were placed in a reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen inlet tube. .00 g (0.035 mol), 24.90 g (0.168 mol) of 2,2-dimethylolbutanoic acid, 168.17 g (0.672 mol) of 4,4'-diphenylmethane diisocyanate (MDI) and Karenz MOI ( 14.78 g (0.095 mol) of 2-isocyanatoethyl methacrylate manufactured by Showa Denko Co., Ltd. was charged, and 0.168 g (1.105 mmol) of 1,8-diazabicyclo[5.4.0]-7-undecene was used as a catalyst. was added and dissolved in 362.1 g of cyclohexanone and 362.1 g of methyl ethyl ketone as solvents. Then, after reacting at 80° C. for 6 hours while stirring under a nitrogen stream, 0.670 g (1.681 mmol) of lauroyl peroxide was added and further reacted at 80° C. for 5 hours. .78 g (0.190 mol) is added, diluted with 939.6 g of methyl ethyl ketone, and the solution temperature is cooled to room temperature to obtain a pale yellow and viscous urethane resin (PU-3) having a nonvolatile content of 25% by mass. A solution was obtained. By the same NMR method as in Example 1, it was confirmed that most of the radically polymerizable double bonds had disappeared.

(Example 4)
GK390 (manufactured by Toyobo Co., Ltd., polyester polyol, acid value less than 1 eq/t) 393.53 g (0.026 mol), 2,2-dimethylol were added to a reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen inlet tube. 19.68 g (0.133 mol) of butanoic acid, 37.32 g (0.149 mol) of 4,4′-diphenylmethane diisocyanate (MDI) and 3.36 g (2-isocyanatoethyl methacrylate, manufactured by Showa Denko Co., Ltd.) of Karenz MOI ( 0.022 mol) was charged, 0.037 g (0.245 mmol) of 1,8-diazabicyclo[5.4.0]-7-undecene was added as a catalyst, and 298.6 g of cyclohexanone and 298.6 g of methyl ethyl ketone were added as solvents. Dissolved. Then, after reacting at 80° C. for 6 hours while stirring under a nitrogen stream, 0.151 g (0.379 mmol) of lauroyl peroxide was added and further reacted at 80° C. for 5 hours. .36 g (0.044 mol) is added, diluted with 760.0 g of methyl ethyl ketone, and the solution temperature is cooled to room temperature to obtain a pale yellow and viscous urethane resin (PU-4) having a nonvolatile content of 25% by mass. A solution was obtained. By the same NMR method as in Example 1, it was confirmed that most of the radically polymerizable double bonds had disappeared.

(Example 5)
394.74 g (0.013 mol) of UR3200 (manufactured by Toyobo Co., Ltd., polyurethane polyol, acid value less than 1 eq/t) and 2,2-dimethylol were placed in a reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen inlet tube. 19.74 g (0.133 mol) of butanoic acid, 35.53 g (0.142 mol) of 4,4′-diphenylmethane diisocyanate (MDI) and 3.09 g (2-isocyanatoethyl methacrylate, manufactured by Showa Denko Co., Ltd.) of Karenz MOI ( 0.020 mol) was charged, 0.036 g (0.233 mmol) of 1,8-diazabicyclo[5.4.0]-7-undecene was added as a catalyst, and 298.8 g of cyclohexanone and 298.8 g of methyl ethyl ketone were added as solvents. Dissolved. After that, the mixture was reacted at 80° C. for 6 hours while stirring under a nitrogen stream, then 0.139 g (0.349 mmol) of lauroyl peroxide was added, and the mixture was further reacted at 80° C. for 5 hours. .139 g (0.002 mol) is added, diluted with 760.1 g of methyl ethyl ketone, and the solution temperature is cooled to room temperature to obtain a pale yellow and viscous urethane resin (PU-5) having a nonvolatile content of 25% by mass. A solution was obtained. By the same NMR method as in Example 1, it was confirmed that most of the radically polymerizable double bonds had disappeared.

(Example 6)
ETERNACOLL UM90 (1/1) (manufactured by Ube Industries, polycarbonate polyol) 107.14 g (0.119 mol), PTMG2000 (manufactured by Mitsubishi Chemical Co., Ltd.), , polyether polyol) 71.43 g (0.036 mol), 2,2-dimethylolbutanoic acid 10.71 g (0.072 mol), hexamethylene diisocyanate (HDI) 35.71 g (0.212 mol) and Karenz 4.79 g (0.031 mol) of MOI (manufactured by Showa Denko KK, 2-isocyanatoethyl methacrylate) was charged, and 0.036 g (0.234 mol) of 1,8-diazabicyclo[5.4.0]-7-undecene was added as a catalyst. millimoles) was added and dissolved in 149.4 g of cyclohexanone and 149.4 g of methyl ethyl ketone as solvents. Then, after reacting at 80° C. for 6 hours while stirring under a nitrogen stream, 0.216 g (0.541 mmol) of lauroyl peroxide was added and further reacted at 80° C. for 5 hours. .79 g (0.062 mol) is added, diluted with 385.5 g of methyl ethyl ketone, and the solution temperature is cooled to room temperature to obtain a pale yellow and viscous urethane resin (PU-6) having a nonvolatile content of 25% by mass. A solution was obtained. By the same NMR method as in Example 1, it was confirmed that most of the radically polymerizable double bonds had disappeared.

(Example 7)
ETERNACOLL UM-90 (1/1) (manufactured by Ube Industries, polycarbonate polyol) 99.00 g (0.110 mol), PTMG2000 (Mitsubishi Chemical Co., Ltd., polyether polyol) 81.00 g (0.041 mol), 2,2-dimethylolbutanoic acid 3.60 g (0.024 mol), 4,4′-diphenylmethane diisocyanate (MDI) 41.40 g (0 .165 mol) and 3.69 g (0.024 mol) of Karenz MOI (manufactured by Showa Denko Co., Ltd., 2-isocyanatoethyl methacrylate) were charged, and 1,8-diazabicyclo[5.4.0]-7-undecene was added as a catalyst. 0.041 g (0.272 mmol) was added and dissolved in 149.5 g of cyclohexanone and 149.5 g of methyl ethyl ketone as solvents. After that, the mixture was reacted at 80° C. for 6 hours while stirring under a nitrogen stream, then 0.166 g (0.417 mmol) of lauroyl peroxide was added, and the mixture was further reacted at 80° C. for 5 hours. .69 g (0.048 mol) is added, diluted with 385.5 g of methyl ethyl ketone, and the solution temperature is cooled to room temperature to obtain a pale yellow and viscous urethane resin (PU-7) having a nonvolatile content of 25% by mass. A solution was obtained. By the same NMR method as in Example 1, it was confirmed that most of the radically polymerizable double bonds had disappeared.

(Example 8)
ETERNACOLL UM90 (1/1) (manufactured by Ube Industries, polycarbonate polyol) 78.95 g (0.088 mol), PTMG2000 (manufactured by Mitsubishi Chemical Co., Ltd.), , polyether polyol) 78.95 g (0.039 mol), 2,2-dimethylolbutanoic acid 15.00 g (0.101 mol), 4,4'-diphenylmethane diisocyanate (MDI) 52.21 g (0.209 mol) and 4.83 g (0.031 mol) of Karenz MOI (manufactured by Showa Denko Co., Ltd., 2-isocyanatoethyl methacrylate), and 0.052 g of 1,8-diazabicyclo[5.4.0]-7-undecene as a catalyst. (0.343 mmol) was added and dissolved in 149.4 g of cyclohexanone and 149.4 g of methyl ethyl ketone as solvents. Then, after reacting at 80° C. for 6 hours while stirring under a nitrogen stream, 0.218 g (0.546 mmol) of lauroyl peroxide was added and further reacted at 80° C. for 5 hours. .83 g (0.062 mol) is added, diluted with 384.9 g of methyl ethyl ketone, and the solution temperature is cooled to room temperature to obtain a pale yellow and viscous urethane resin (PU-8) having a nonvolatile content of 25% by mass. A solution was obtained. By the same NMR method as in Example 1, it was confirmed that most of the radically polymerizable double bonds had disappeared.

(Example 9)
283.29 g (0.497 mol) of pripol 2033 (manufactured by Croda Japan Co., dimer polyol) and 70% of Duranol T5652 (manufactured by Asahi Kasei Chemicals, polycarbonate polyol) were placed in a reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen inlet tube. .00 g (0.035 mol), 24.90 g (0.168 mol) of 2,2-dimethylolbutanoic acid, 168.17 g (0.672 mol) of 4,4'-diphenylmethane diisocyanate (MDI) and Karenz MOI ( 14.78 g (0.095 mol) of 2-isocyanatoethyl methacrylate manufactured by Showa Denko Co., Ltd. was charged, and 0.168 (1.105 mmol) of 1,8-diazabicyclo[5.4.0]-7-undecene was used as a catalyst. was added and dissolved in 362.1 g of cyclohexanone and 362.1 g of methyl ethyl ketone as solvents. Then, after reacting at 80° C. for 6 hours while stirring under a nitrogen stream, 0.449 g (1.13 mmol) of lauroyl peroxide was added and further reacted at 80° C. for 5 hours. .78 g (0.190 mol) is added, diluted with 939.6 g of methyl ethyl ketone, and the solution temperature is cooled to room temperature to obtain a pale yellow and viscous urethane resin (PU-9) having a nonvolatile content of 25% by mass. A solution was obtained. By the same NMR method as in Example 1, it was confirmed that most of the radically polymerizable double bonds had disappeared.

(Example 10)
283.29 g (0.497 mol) of pripol 2033 (manufactured by Croda Japan Co., dimer polyol) and 70% of Duranol T5652 (manufactured by Asahi Kasei Chemicals, polycarbonate polyol) were placed in a reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen inlet tube. .00 g, (0.035 mol), 24.90 g (0.168 mol) of 2,2-dimethylolbutanoic acid, 168.17 g (0.672 mol) of 4,4'-diphenylmethane diisocyanate (MDI) and Karenz MOI 14.78 g (0.095 mol) of 2-isocyanatoethyl methacrylate (manufactured by Showa Denko Co., Ltd.) was charged, and 0.168 (1.105 mmol) of 1,8-diazabicyclo[5.4.0]-7-undecene was used as a catalyst. ) was added and dissolved in 362.1 g of cyclohexanone and 362.1 g of methyl ethyl ketone as solvents. Then, after reacting at 80° C. for 6 hours while stirring under a nitrogen stream, 1.34 g (3.36 mmol) of lauroyl peroxide was added and further reacted at 80° C. for 5 hours. .78 g (0.190 mol) is added, diluted with 939.6 g of methyl ethyl ketone, and the solution temperature is cooled to room temperature to obtain a pale yellow and viscous urethane resin (PU-10) having a nonvolatile content of 25% by mass. A solution was obtained. By the same NMR method as in Example 1, it was confirmed that most of the radically polymerizable double bonds had disappeared.

(Comparative example 1)
In a reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen inlet tube, 139.75 g (0.245 mol) of pripol 2033 (manufactured by Croda Japan, dimer polyol), 9.78 g of 2,2-dimethylolbutanoic acid ( 0.066 mol), 75.47 g (0.302 mol) of 4,4′-diphenylmethane diisocyanate (MDI) and 6.56 g (0.042 mol) of Karenz MOI (manufactured by Showa Denko Co., Ltd., 2-isocyanatoethyl methacrylate). 0.075 (0.495 mmol) of 1,8-diazabicyclo[5.4.0]-7-undecene was added as a catalyst and dissolved in 137.5 g of cyclohexanone and 137.5 g of methyl ethyl ketone as solvents. Then, after reacting at 80° C. for 6 hours while stirring under a nitrogen stream, 6.56 g (0.079 mol) of n-butanol is added, diluted with 400.0 g of methyl ethyl ketone, and the solution temperature is raised to room temperature. By cooling, a pale yellow viscous urethane resin (PU-11) solution having a non-volatile content of 25% by mass was obtained. By the same NMR method as in Example 1, it was confirmed that radically polymerizable double bonds remained.

(Comparative example 2)
In a reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen inlet tube, 139.75 g (0.245 mol) of pripol 2033 (manufactured by Croda Japan, dimer polyol), 9.78 g of 2,2-dimethylolbutanoic acid ( 0.066 mol) and 226.41 g (0.906 mol) of 4,4'-diphenylmethane diisocyanate (MDI) were charged, and 0.075 g of 1,8-diazabicyclo[5.4.0]-7-undecene as a catalyst ( 0.495 mmol) was added and dissolved in 137.5 g of cyclohexanone and 137.5 g of methyl ethyl ketone as solvents. After that, when the reaction was carried out at 80°C while stirring under a nitrogen stream, the molecular weight increased due to the large excess of MDI relative to the polyol, and the polymerization solution gelled, resulting in a urethane resin (PU-12) solution. could not get

(Comparative Example 3)
444.66 g (0.022 mol) of UR3958 (Toyobo Co., Ltd., polyurethane polyol, acid value less than 1 eq/t) and 2,2-dimethylol were added to a reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen inlet tube. 19.68 g (0.133 mol) of butanoic acid, 5.34 g (0.021 mol) of 4,4′-diphenylmethane diisocyanate (MDI) and 0.47 g (2-isocyanatoethyl methacrylate, manufactured by Showa Denko Co., Ltd.) of Karenz MOI ( 0.003 mol) was charged, 0.005 g (0.035 mmol) of 1,8-diazabicyclo[5.4.0]-7-undecene was added as a catalyst, and 298.3 g of cyclohexanone and 298.3 g of methyl ethyl ketone were added as solvents. Dissolved. Then, after reacting at 80° C. for 6 hours while stirring under a nitrogen stream, 0.021 g (0.053 mmol) of lauroyl peroxide was added and further reacted at 80° C. for 5 hours. .47 g (0.006 mol) is added, diluted with 754.4 g of methyl ethyl ketone, and the solution temperature is cooled to room temperature to obtain a pale yellow and viscous urethane resin (PU-13) having a nonvolatile content of 25% by mass. A solution was obtained. By the same NMR method as in Example 1, it was confirmed that most of the radically polymerizable double bonds had disappeared.

(Comparative Example 4)
ETERNACOLL UM90 (1/1) (manufactured by Ube Industries, polycarbonate polyol) 77.92 g (0.137 mol), PTMG2000 (manufactured by Mitsubishi Chemical Co., Ltd.) , polyether polyol) 116.88 g (0.058 mol), 2,2-dimethylolbutanoic acid 10.71 g (0.072 mol), 4,4'-diphenylmethane diisocyanate (MDI) 19.48 g (0.078 mol) and 2.94 g (0.019 mol) of Karenz MOI (manufactured by Showa Denko Co., Ltd., 2-isocyanatoethyl methacrylate), and 0.020 g of 1,8-diazabicyclo[5.4.0]-7-undecene as a catalyst. (0.128 mmol) was added and dissolved in 148.3 g of cyclohexanone and 148.3 g of methyl ethyl ketone as solvents. Then, after reacting at 80° C. for 6 hours while stirring under a nitrogen stream, 0.132 g (0.331 mmol) of lauroyl peroxide was added and further reacted at 80° C. for 5 hours. .94 g (0.038 mol) is added, diluted with 403.0 g of methyl ethyl ketone, and the solution temperature is cooled to room temperature to obtain a pale yellow and viscous urethane resin (PU-14) having a nonvolatile content of 25% by mass. A solution was obtained. By the same NMR method as in Example 1, it was confirmed that most of the radically polymerizable double bonds had disappeared.

Table 1 shows the properties of the urethane resins obtained in the above Examples and Comparative Examples, and Table 2 shows the test evaluation results.

In Comparative Example 1, since the weight average molecular weight was small, the tensile elongation was also small, and cracks occurred in the flexibility test. In Comparative Example 2, the molecular weight distribution (Mw/Mn) was increased to the same level as in Comparative Example 1 by urethane polymerization, but the polymerization solution gelled and a urethane resin solution could not be obtained. In Comparative Example 3, since the glass transition temperature of the polyol as a whole and the glass transition temperature of the urethane resin after production were both low, tack occurred at 40°C. In Comparative Example 4, although the molecular weight distribution (Mw/Mn) was high, the elongation was low due to the low weight average molecular weight, and cracks occurred in the flexibility test. On the other hand, as can be seen from Table 2, in Examples 1 to 10, urethane resins having good tack resistance and flexibility (flexibility, elongation) were obtained.

Since the urethane resin of the present invention is excellent in tack resistance, there is no sticking problem even when it is applied to a film and stored in a roll form. Moreover, since it is excellent in flexibility, it can be used as an adhesive composition that requires bending resistance, and is particularly useful as an adhesive for FPC.

Claims (8)

A urethane resin that satisfies the following (1) to (3) and has a carboxyl group .
(1) Glass transition temperature (Tg) is 40° C. or higher (2) Weight average molecular weight (Mw) is 180,000 to 2,000,000 (3) Molecular weight distribution (Mw/Mn) is 9 to 200 (where Mn represents the number average molecular weight) A radically polymerizable double bond derived from a compound (C) in which the urethane resin has a functional group reactive with a hydroxyl group or an isocyanate group and a radically polymerizable double bond in the same molecule, and the compound (C) 2. The urethane resin according to claim 1, which has at least one of the polymers of as a structural unit. 3. The urethane resin according to claim 1 , wherein the urethane resin has an acid value of 50 to 500 eq/t. The urethane resin has a polyol (A) as a structural unit, and the polyol (A) contains at least one polyol selected from the group consisting of polyester polyols, polyether polyols, polycarbonate polyols and polyolefin polyols. The urethane resin according to any one of claims 1 to 3 , wherein the polyol (A) has a glass transition temperature of -30 to 30°C. A resin composition comprising the urethane resin according to any one of claims 1 to 4 and a cross-linking agent. 6. The resin composition according to claim 5 , wherein the cross-linking agent contains an epoxy resin or an isocyanate resin. An adhesive composition containing the resin composition according to claim 5 or 6 . At least a polyol (A), a polyisocyanate compound (B), a compound (C) having a functional group reactive with a hydroxyl group or an isocyanate group and a radically polymerizable double bond in the same molecule and one or more carboxyl groups A method for producing a urethane resin that satisfies the following (1) to (3), characterized by further radically polymerizing a urethane polymer having a polyol (D) having as a structural unit.
(1) Glass transition temperature (Tg) is 40° C. or higher
(2) Weight average molecular weight (Mw) is 180000 to 2000000
(3) molecular weight distribution (Mw/Mn) is 9 to 200