JP2006124549A - Photo-curable resin composition and adhesive for optical discs - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultraviolet-curable resin composition excellent in photo-curability and adhesion and resistant to yellowing. <P>SOLUTION: The ultraviolet-curable resin composition comprises (A) a urethane (meth)acrylate obtained from at least one diol component selected from the group consisting of polypropylene glycol, polybutylene glycol, a copolymer of 1,2-butylene oxide and ethylene oxide, and a copolymer of propylene oxide and ethylene oxide, a diisocyanate, and a hydroxy group-containing (meth)acrylate; and (B) a radical-polymerizable compound; and contains (C) photopolymerization initiators at a ratio of 0.1-15 mass%, of only those which have absorbance (1 cm of optical path length) of ≥0.2 at 365 nm of 0.1 mass% solution. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ultraviolet curable resin composition suitable for an adhesive such as a polymer material. Specifically, the present invention relates to a liquid curable composition for adhesives in the fields of optical disks (DVDs), various building materials, packaging materials, printing materials, display materials, electric / electronic component materials, optical component materials, liquid crystal panels, and the like.

  With the development of information communication equipment, various display devices have been proposed. For example, those using a CRT, those using a liquid crystal panel, those performing projection by projecting light onto a screen, those using a PDP panel, and the like can be mentioned. In these display devices, it is necessary to secure display performance by attaching polymer films, polymer lenses, and the like having various optical characteristics. In addition, a method has been proposed in which a lens is optically treated with a polymer film, and it is necessary to bond the lens substrate to the polymer film.

  Various adhesives can be used for adhesion of the polymer material. For example, (a) urethane (meth) acrylate having a small number average molecular weight (5000 to 15000), (b) acryloylmorpholine, dimethylacrylamide, The liquid curable adhesive / adhesive composition containing a compound selected from diethyl acrylamide and diisopropyl acrylamide and (c) phenoxypolyethylene glycol (PEG = 1 to 5) acrylate has excellent adhesion to PVC and PET. Has been reported (see Patent Document 1). In recent years, the tendency to desire a solvent-free adhesive excellent in environmental protection without using a solvent and improving the environment has been strengthened for adhesion of such a polymer material. Solvent-free adhesives that can be bonded by irradiation with radiation, particularly UV light, are expected as materials that satisfy these requirements.

  In the case of bonding materials having optical characteristics, it is necessary that the adhesive does not change its hue by heating, exposure to ultraviolet rays, or the like, but a material that sufficiently satisfies this demand has not been obtained.

  On the other hand, (1) urethane (meth) acrylate, (2) silane compound having a mercapto group, (3) photopolymerization initiator, (4) an ethylenically unsaturated monomer having an amino group, and (5) (meth) acrylate compound It has been reported that a photo-curable resin composition containing a copper is useful as a coating layer for a copper-coated copper wire used as a tension member of an optical fiber unit (see Patent Document 2).

  Further, Patent Document 3 describes that the use of a specific phenolic compound in a multilayer coating improves yellowing of a fluorescent lamp, but does not describe use in an adhesive.

  In recent years, with the development of information technology including computer device technology, computer software technology, communication technology, etc., more information can be transmitted at high speed. Accordingly, a recording medium capable of recording a larger amount of information at a high density is desired and is being developed. As such a high-density recording medium, a DVD (referred to as a digital video disk or a digital versatile disk) has been developed as a next-generation general-purpose recording medium. Unlike conventional CDs (compact discs), DVDs are manufactured by laminating two discs, so an adhesive for lamination is required. Hot melt adhesives, thermosetting adhesives, anaerobic curing adhesives Attempts have been made to use. However, the hot melt adhesive has insufficient heat stability and weather resistance and is softened in a high temperature environment, so that there is a problem in that the adhesive strength is lowered and the bonded disc is peeled off or deformed. Further, since the transparency is not high, it is difficult to use the DVD with a two-layer structure having a semi-transmissive film as a recording film. The thermosetting adhesive has problems such as deformation of the base material constituting the disk due to heat at the time of curing, and a long time for curing. Anaerobic adhesives also have the problem of low productivity because it takes time to cure. As a method for solving such a problem, a photo-curing adhesive has been proposed. For example, Patent Documents 4 to 6 disclose ultraviolet curable resin adhesives mainly composed of urethane acrylate.

JP-A-7-310067 JP 2000-198824 A JP 2002-264276 A Japanese Patent Laid-Open No. 61-142545 JP-A-6-89462 JP 2004-139706 A

However, the compositions of Patent Documents 1 and 2 have problems such as insufficient adhesive strength.
In addition, LED light sources having a sharp emission spectrum at 365 nm have features that have a longer life than conventional mercury lamps and metal halide lamps and greatly reduce variations in irradiation intensity. This light source is a DVD based on a photocurable adhesive. However, the conventional photocurable resins such as Patent Documents 4 and 5 have poor curing. Furthermore, a photocurable resin that can sufficiently prevent corrosion of the metal vapor-deposited film, which is a recording layer of DVD, from moisture has not been obtained.
The objective of this invention is providing the ultraviolet curable resin composition which is excellent in photocurability and adhesiveness, and has little yellowing.

  In order to achieve the above object, the present inventors have conducted intensive research, and in the conventional photocurable resin, the light absorption rate at 365 nm was as low as 5%, and the curing was poor, but the absorption of light at 365 nm was not achieved. When the light absorption rate was increased to 20% or more by using a large polymerization initiator, it was found that the curability of the photocurable resin was improved, and the present invention was completed.

According to the present invention, an ultraviolet curable resin composition and an adhesive for DVD are obtained below.
1. (A) at least one diol component selected from the group consisting of polypropylene glycol, polybutylene glycol, a copolymer of 1,2-butylene oxide and ethylene oxide, and a copolymer of propylene oxide and ethylene oxide, a diisocyanate, and a hydroxyl group Containing urethane (meth) acrylate obtained from contained (meth) acrylate, and (B) radical polymerizable compound, and (C) as a photopolymerization initiator, absorbance at 365 nm of 0.1% by weight solution (optical path length 1 cm) The ultraviolet curable resin composition which contains only the photoinitiator whose 0.1) is 0.2 or more in the ratio of 0.1-15 mass%. (C) As a photopolymerization initiator, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-methyl-1- [4-methylthiophenyl] -2-morpholinopropan-1-one and 2-benzyl-2 -It is preferable that it is 1 type (s) or 2 or more types selected from the group which consists of dimethylamino-1- (4-morpholinophenyl) butanone-1.
2. 2. An adhesive for DVD comprising the ultraviolet curable resin composition described in 1 above.

According to the present invention, since an ultraviolet curable resin composition having a high light absorption at 365 nm is obtained, the photocurability of the resin composition by the LED light source is improved, and in particular, DVD bonding using the LED light source is performed. And an adhesive for DVD excellent in curability can be obtained.
According to the present invention, there can be obtained an ultraviolet curable resin composition having an appropriate viscosity for coating without a solvent, sufficient adhesion to a polymer material, and little hue change upon heating or ultraviolet exposure. .

1. Ultraviolet curable resin composition (1) Component (A) Urethane (meth) acrylate Urethane (meth) acrylate as component (A) used in the present invention is (a) diisocyanate, (b) hydroxyl group-containing (meth) acrylate. And (c) produced by reacting a diol component. That is, it is produced by reacting the isocyanate group of diisocyanate with the hydroxyl group of diol and the hydroxyl group of hydroxyl group-containing (meth) acrylate, respectively.

  As this reaction, for example, diol, diisocyanate and hydroxyl group-containing (meth) acrylate are charged together and reacted; diol and diisocyanate are reacted, and then hydroxyl group-containing (meth) acrylate is reacted; diisocyanate and hydroxyl group-containing (meta) A method of reacting acrylate and then reacting diol; reacting diisocyanate and hydroxyl group-containing (meth) acrylate, then reacting diol, and finally reacting hydroxyl group-containing (meth) acrylate again.

  Component (A) adjusts the reaction ratio of diol and diisocyanate so that the diol is preferably contained in one molecule as a repeating unit of 2 or more molecules, more preferably as a repeating unit of 3 or more molecules in one molecule. And react. Specifically, the molar ratio of the diisocyanate is adjusted so that the diisocyanate is 1.5 mol or less with respect to 1 mol of the diol. The hydroxyl group-containing (meth) acrylate is preferably adjusted to 1.0 to 1.5 equivalents with respect to the excess isocyanate equivalent calculated from the molar ratio of diol and diisocyanate.

  In the reaction of these compounds, copper naphthenate, cobalt naphthenate, zinc naphthenate, di-n-butyltin laurate, di-n-butyltin acetate, di-n-butyltin maleate, di-n-octyltin laurate, diacetate acetate n-octyltin, di-n-octyltin maleate, triethylamine, 1,4-diazabicyclo [2.2.2] octane, 2,6,7-trimethyl-1,4-diazabicyclo [2.2.2] octane, 4 It is preferable to use 0.01 to 1 part by mass of a urethane catalyst such as divalent zirconium salt such as di-n-octyltin neodecanoate or zirconium tetraacetylacetonate with respect to 100 parts by mass of the total amount of the reactants. The reaction temperature is usually 10 to 90 ° C, particularly preferably 30 to 80 ° C.

  Examples of the diisocyanate as component (a) include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 3,3′-dimethylphenylene diisocyanate, 4,4′-biphenylene diisocyanate, 1,6-hexane diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), 2,2,4-trimethylhexamethylene diisocyanate, bis (2-isocyanate) Toethyl) fumarate, 6-isopropyl-1,3-phenyl diisocyanate, 4-diphenylpropane diisocyanate, lysine diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, tetramethylxylylene diisocyanate, 2,5 (or 6) -bis (Isocyanatemethyl) -bicyclo [2.2.1] heptane and the like. Of these, 2,4-tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, and methylene bis (4-cyclohexyl isocyanate), which are aliphatic compounds, are particularly preferable. By using an aliphatic compound for the diisocyanate component, yellowing during heating is suppressed. Isophorone diisocyanate and methylene bis (4-cyclohexylisocyanate) are preferred when seeking better yellowing during heating.

  These diisocyanates can be used alone or in combination of two or more.

  Examples of the (b) component hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 2-hydroxy-3-phenyloxy. Propyl (meth) acrylate, 1,4-butanediol mono (meth) acrylate, 2-hydroxyalkyl (meth) acryloyl phosphate, 4-hydroxybutyl (meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, 1,6 -Hexanediol mono (meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolethane di (meth) acrylate, pentaerythritol tri (meth) Examples include compounds obtained by addition reaction of glycidyl group-containing compounds such as acrylate, dipentaerythritol penta (meth) acrylate, alkyl glycidyl ether, allyl glycidyl ether, glycidyl (meth) acrylate, and (meth) acrylic acid. it can. Of these hydroxyl group-containing (meth) acrylates, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and the like are particularly preferable.

  These hydroxyl group-containing (meth) acrylate compounds can be used alone or in combination of two or more.

  In the present invention, the component diol (c) is at least one selected from the group consisting of polypropylene glycol, polybutylene glycol, a copolymer of 1,2-butylene oxide and ethylene oxide, and a copolymer of propylene oxide and ethylene oxide. Diol. Further, other polyols or mixtures of polyols different from these diols can be used in addition to the component (c).

  (C) The number average molecular weight of the diol is preferably 300 to 15,000, more preferably 1,000 to 12,000, and particularly preferably 2,000 to 12,000.

  The following can be illustrated as a commercial item of (c) component. Polypropylene glycol is, for example, PPG-400, PPG1000, PPG2000, PPG3000, EXCENOL720, 1020, 2020, PREMINOL PML S-X4001, PML S-4003, PML S-X4004, PML S-X4008, PML S-X4011, PML S-. X4016, NPML-4002A (above, Asahi Glass Urethane Co., Ltd.) and other commercial products are available. Diols that are copolymers of 1,2-butylene oxide and ethylene oxide are, for example, EO / BO500, EO / BO1000, EOBO / 2000, EO / BO3000, EO / BO4000 (above, manufactured by Daiichi Kogyo Seiyaku). Can be obtained as a commercial product.

  These diol components (c) can be used alone or in combination of two or more. Examples of other polyols or polyol mixtures other than (c) include aliphatic or cyclic polyether diols, polyester diols, polycarbonate diols, polycaprolactone diols, and the like. These polyols are not particularly limited in the polymerization mode of each structural unit, and for example, any of a random polymer, a block polymer, and a graft polymer may be used. Examples of the aliphatic polyether diol include ring-opening copolymerization of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene glycol, polyheptamethylene glycol, polydecamethylene glycol, or two or more ion-polymerizable cyclic compounds. And polyether diol obtained by the above. Examples of the ion polymerizable cyclic compound include ethylene oxide, propylene oxide, 1,2-butylene oxide, butene-1-oxide, isobutene oxide, 3,3-bischloromethyloxetane, tetrahydrofuran, 2-methyltetrahydrofuran, and 3-methyl. Tetrahydrofuran, dioxane, trioxane, tetraoxane, cyclohexene oxide, styrene oxide, epichlorohydrin, glycidyl methacrylate, allyl glycidyl ether, allyl glycidyl carbonate, butadiene monooxide, isoprene monooxide, vinyl oxetane, vinyl tetrahydrofuran, vinyl cyclohexene oxide, phenyl glycidyl ether, butyl Cyclic ethers such as glycidyl ether and glycidyl benzoate Kind, and the like. Polyether diol obtained by ring-opening copolymerization of the above ion polymerizable cyclic compound with cyclic imines such as ethyleneimine, cyclic lactone acids such as β-propiolactone and glycolic acid lactide, or dimethylcyclopolysiloxanes. Can also be used. Specific combinations of the two or more ion-polymerizable cyclic compounds include, for example, tetrahydrofuran and propylene oxide, tetrahydrofuran and 2-methyltetrahydrofuran, tetrahydrofuran and 3-methyltetrahydrofuran, tetrahydrofuran and ethylene oxide, propylene oxide and ethylene oxide, butene-1 And terpolymers of -oxide and ethylene oxide, tetrahydrofuran, butene-1-oxide, ethylene oxide, and the like. The ring-opening copolymer of these ion-polymerizable cyclic compounds may be bonded at random or may be bonded in a block form.

  Polyether diols as described above are, for example, PTMG650, PTMG1000, PTMG2000 (above, manufactured by Mitsubishi Chemical Corporation), PEG1000, Unisafe DC1100, DC1800 (above, manufactured by NOF Corporation), PPTG2000, PPTG1000, PTG400, PTGL2000 ( As mentioned above, it can also be obtained as a commercial product such as Hodogaya Chemical Co., Ltd.), Z-3001-4, Z-3001-5, PBG2000A, PBG2000B (above, Daiichi Kogyo Seiyaku Co., Ltd.).

  Examples of the cyclic polyether diol include bisphenol A alkylene oxide addition diol, bisphenol F alkylene oxide addition diol, hydrogenated bisphenol A, hydrogenated bisphenol F, hydrogenated bisphenol A alkylene oxide addition diol, and hydrogenated bisphenol F. Alkylene oxide addition diol, alkylene oxide addition diol of hydroquinone, alkylene oxide addition diol of naphthohydroquinone, alkylene oxide addition diol of anthrahydroquinone, 1,4-cyclohexanediol and its alkylene oxide addition diol, tricyclodecanediol, tricyclodecanedi Methanol, pentacyclopentadecanediol, pentacyclopentadecane dimethanol, etc. It is below. Among these, alkylene oxide addition diol of bisphenol A, alkylene oxide addition diol of hydrogenated bisphenol A, and tricyclodecane dimethanol are preferable. These polyols are, for example, Uniol DA400, DA700, DA1000, DB400 (manufactured by NOF Corporation), N1162 (Daiichi Kogyo Seiyaku Co., Ltd.), tricyclodecane dimethanol (Mitsubishi Chemical Corporation). It can also be obtained as a commercial product.

  Examples of the polyester diol include a polyester diol obtained by reacting a diol with a diacid base. Examples of the diol include ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, tetramethylene glycol, polytetramethylene glycol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, 3-methyl- Examples include 1,5-pentanediol, 1,9-nonanediol, and 2-methyl-1,8-octanediol. Examples of the dibasic acid include phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, adipic acid, and sebacic acid. Commercially available products include Kurapol P-2010, PMIPA, PKA-A, PKA-A2, PNA-2000 (above, manufactured by Kuraray Co., Ltd.) and the like.

  Examples of the polycarbonate diol include polycarbonate of polytetrahydrofuran and polycarbonate of 1,6-hexanediol, and commercially available products include DN-980, 981, 982, and 983 (above, manufactured by Nippon Polyurethane Co., Ltd.), PC-8000 (manufactured by PPG, USA), PC-THF-CD (manufactured by BASF) and the like can be mentioned.

  Furthermore, as polycaprolactone diol, for example, ε-caprolactone and ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, tetramethylene glycol, polytetramethylene glycol, 1,2-polybutylene glycol, 1,6-hexanediol, neo Examples thereof include polycaprolactone diols obtained by reacting diols such as pentyl glycol, 1,4-cyclohexanedimethanol, 1,4-butanediol and the like. These diols are commercially available from Plaxel 205, 205AL, 212, 212AL, 220, 220AL (above, manufactured by Daicel Corporation).

  Many diols other than those described above can also be used. Examples of such diol include dimethylol compounds of ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, and dicyclopentadiene. , Tricyclodecane dimethanol, β-methyl-δ-valerolactone, hydroxy-terminated polybutadiene, hydroxy-terminated hydrogenated polybutadiene, castor oil-modified polyol, polydimethylsiloxane-terminated diol compound, polydimethylsiloxane carbitol-modified diol, etc. .

  Besides using the diol as described above, it is also possible to use a diamine together with a diol. Examples of such diamines include diamines such as ethylene diamine, tetramethylene diamine, hexamethylene diamine, paraphenylene diamine, and 4,4'-diaminodiphenyl methane, diamines containing hetero atoms, and polyether diamines.

  Among the diols, polyether diol, alkylene oxide addition diol of bisphenol A and alkylene oxide addition diol of hydrogenated bisphenol A are preferable. Commercially available products are PTMG650, PTMG1000, PTMG2000 (manufactured by Mitsubishi Chemical Corporation), UNIOR DA400, DA700, DA1000, DB400 (manufactured by NOF Corporation), N1162 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.). it can.

  The number average molecular weight of these other diol components is 300 to 5,000, preferably 300 to 2,000, and more preferably 300 to 1,000.

  The component (A) urethane (meth) acrylate is preferably blended in an amount of 1 to 95% by weight, more preferably 5 to 80% by weight, based on the total amount of the ultraviolet curable resin composition of the present invention. It is particularly preferable that 30 to 60% by mass is blended. If it is less than 1% by mass or exceeds 95% by mass, the coatability may be impaired. By using the component (A), a highly sticky cured product (adhesive) can be obtained.

  The ultraviolet curable resin composition of the present invention may further contain a urethane (meth) acrylate obtained by reacting 2 mol of a hydroxyl group-containing (meth) acrylate compound with 1 mol of diisocyanate. As such urethane (meth) acrylate, for example, a reaction product of hydroxyethyl (meth) acrylate and 2,4-tolylene diisocyanate, hydroxyethyl (meth) acrylate and 2,5 (or 6) -bis (isocyanate methyl)- Bicyclo [2.2.1] heptane reactant, hydroxyethyl (meth) acrylate and isophorone diisocyanate reactant, hydroxypropyl (meth) acrylate and 2,4-tolylene diisocyanate reactant, hydroxypropyl (meth) acrylate And a reaction product of isophorone diisocyanate.

（式中、Ｒ^２は水素原子又はメチル基を示し、Ｒ^３は炭素数２〜６、好ましくは２〜４のアルキレン基を示し、Ｒ^４は水素原子又は炭素数１〜１２、好ましくは１〜９のアルキル基を示し、ｌは０〜１２、好ましくは１〜８の数を示す）

（式中、Ｒ^５は水素原子又はメチル基を示し、Ｒ^６は炭素数２〜８、好ましくは２〜５のアルキレン基を示し、Ｒ^７は水素原子又はメチル基を示し、ｐは好ましくは１〜４の数を示す。） (2) Component (B) Radical Polymerizable Compound The radical curable compound of component (B) is blended in the ultraviolet curable resin composition of the present invention. Among the radical polymerizable compounds, examples of the monofunctional compound include vinyl group-containing lactams such as N-vinylpyrrolidone and N-vinylcaprolactam, isobornyl (meth) acrylate, bornyl (meth) acrylate, and tricyclodecanyl (meth). Acrylates, alicyclic structure-containing (meth) acrylates such as dicyclopentanyl (meth) acrylate, benzyl (meth) acrylate, 4-butylcyclohexyl (meth) acrylate, acryloylmorpholine, vinylimidazole, vinylpyridine, 2-hydroxy Ethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate , Isopropyl (meth) acrylate, butyl (meth) acrylate, amyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate , Heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate , Dodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate Rate, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, methoxyethylene glycol (meth) ) Acrylate, ethoxyethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, diacetone (meth) acrylamide, isobutoxymethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, t-octyl (meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl ( (Meth) acrylate, 7-amino-3,7-dimethyloctyl (meth) acrylate, N, N-diethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, hydroxybutyl vinyl ether, lauryl vinyl ether, cetyl vinyl ether , 2-ethylhexyl vinyl ether and compounds represented by the following formulas (2) and (3).

(Wherein R ² represents a hydrogen atom or a methyl group, R ³ represents an alkylene group having 2 to 6 carbon atoms, preferably 2 to 4 carbon atoms, and R ⁴ represents a hydrogen atom or 1 to 12 carbon atoms, preferably 1 -9 represents an alkyl group, and l represents a number from 0 to 12, preferably from 1 to 8)

Wherein R ⁵ represents a hydrogen atom or a methyl group, R ⁶ represents an alkylene group having 2 to 8 carbon atoms, preferably 2 to 5 carbon atoms, R ⁷ represents a hydrogen atom or a methyl group, and p is preferably The number of 1-4 is shown.)

  Of these monofunctional compounds, vinyl group-containing lactams such as N-vinylpyrrolidone and N-vinylcaprolactam, isobornyl (meth) acrylate, lauryl acrylate, acryloylmorpholine, and compounds of the above formula (3) are preferred.

  These monofunctional compounds are commercially available products IBXA (manufactured by Osaka Organic Chemical Industry Co., Ltd.), Aronix M-111, M-113, M114, M-117, TO-1210, Aronix M-110 (above, Toagosei) Etc.).

  As for the adhesive strength of the cured product of the ultraviolet curable resin composition prepared as described above to a polymer material, for example, a PET film provides a peel strength of 10 N / m or more.

  In the ultraviolet curable resin composition of the present invention, a polymerizable polyfunctional compound can be further blended as the component (B). Examples of the polymerizable polyfunctional compound include trimethylolpropane tri (meth) acrylate, trimethylolpropane trioxyethyl (meth) acrylate, pentaerythritol tri (meth) acrylate, ethylene glycol di (meth) acrylate, and triethylene glycol diester. Acrylate, tetraethylene glycol di (meth) acrylate, tricyclodecanediyldimethanol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (Meth) acrylate, neopentyl glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, bisphenol A-glycidyl ether end (meth) acrylic acid addition, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, polyester di (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) Acrylate, tris (2-hydroxyethyl) isocyanurate di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, di (meth) acrylate of diol which is an adduct of bisphenol A ethylene oxide or propylene oxide, water Di (meth) acrylate of diol, which is an adduct of ethylene oxide or propylene oxide of bisphenol A, and (meth) acrylate added to diglycidyl ether of bisphenol A It allowed epoxy (meth) acrylate, triethylene glycol divinyl ether.

  Among the polymerizable polyfunctional compounds contained in component (B), tricyclodecanediyldimethanol di (meth) acrylate, di (meth) acrylate of bisphenol A to which ethylene oxide is added, tris (2-hydroxyethyl) isocyanate Nurate tri (meth) acrylate and 1,6-hexanediol di (meth) acrylate are preferred.

  As a commercial item of the polymerizable polyfunctional compound contained in the component (B), for example, Iupimer UV, SA-1002 (manufactured by Mitsubishi Chemical Corporation), Aronix M-215, M-315, M-325 TO-1210 (manufactured by Toagosei Co., Ltd.) and GX-8345 (Daiichi Kogyo Seiyaku Co., Ltd.) can be used.

The monofunctional compound and the polymerizable polyfunctional compound which are component (B) radical polymerizable compounds are, in total, preferably 1 to 95% by mass, more preferably, based on the ultraviolet curable resin composition of the present invention. 5-80 mass%, Especially preferably, it mix | blends by 30-80 mass%.
Among these, it is preferable that 20-80 mass% of polymerizable polyfunctional compounds are mix | blended with 100 mass% of (B) component whole quantity, and it is still more preferable that 40-70 mass% is mix | blended.

(3) Component (C) Photopolymerization Initiator The component (C) photopolymerization initiator compounded in the ultraviolet curable resin composition of the present invention has a light absorption rate at 365 nm of the ultraviolet curable resin composition of the present invention. It is a component to improve. When the photopolymerization initiator of component (C) is contained in the resin composition, the light absorption rate at 365 nm is improved.

  The photopolymerization initiator of component (C) needs to have an absorbance (optical path length of 1 cm) at 365 nm of a 0.1% by mass solution of 0.2 or more. By using a photopolymerization initiator whose absorbance satisfies this requirement, the light absorption rate at 365 nm of the resin composition of the present invention is improved, and excellent curability when an LED light source having a sharp emission spectrum at 365 nm is used. Can be obtained. The absorbance at 365 nm of the 0.1% by weight solution is obtained by dissolving the component (C) at 0.1% by weight in a suitable organic solvent (eg, toluene, acetonitrile, etc.) that has substantially no absorption at 365 nm. Only the used organic solvent can be used as a reference sample, and can be measured with a UV spectrophotometer using a measurement cell having an optical path length of 1 cm.

  Preferable specific examples of component (C) include, for example, (i) 2,4,6-trimethylbenzoyldiphenylphosphine oxide, (ii) 2-methyl-1- [4-methylthiophenyl] -2-morpholinopropane- 1-one and (iii) 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1 and the like. These may be used alone or in combination of two or more. When a photopolymerization initiator not corresponding to the component (C) is used in combination, the light absorption rate at 365 nm of the resin composition of the present invention decreases, and the curability when using an LED light source having a sharp emission spectrum at 365 nm is obtained. Since it may fall, it is preferable not to mix | blend photoinitiators other than a component (C).

  These compounds have a high absorbance at 365 nm (optical path length of 1 cm) of a 0.1 mass% solution of (i) about 0.7, (ii) about 0.4, and (iii) 1 or more, respectively. With this light absorption property, the light absorption rate at 365 nm of the entire ultraviolet curable resin composition of the present invention containing these compounds can be increased.

  A commercial item can be used as said 3 types of compounds which are a component (C) photoinitiator. Specifically, (i) 2,4,6-trimethylbenzoyldiphenylphosphine oxide, Lucirin TPO (manufactured by BASF); (ii) 2-methyl-1- [4-methylthiophenyl] -2-morpholinopropane As -1-one, Irgacure 907 (manufactured by Ciba Specialty Chemicals); and (iii) 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1, as Irgacure 369 (Ciba Specialty Chemicals) Manufactured).

  On the other hand, specific examples of photopolymerization initiators that do not fall under Component (C) because the absorbance at 365 nm (optical path length 1 cm) of a 0.1% by mass solution are less than 0.2 include benzyldimethyl ketal and 1-hydroxycyclohexyl. Examples thereof include phenyl ketone and 2-hydroxy-2-methyl-1-phenylpropan-1-one.

  The photopolymerization initiator of component (C) is blended in an amount of 0.1 to 15% by mass, preferably 0.3 to 10% by mass, with the total amount of the ultraviolet curable resin composition of the present invention as 100% by mass. . If it exists in the range of 0.1-15 mass%, the light absorption factor in 365 nm of the ultraviolet curable resin composition of this invention can be increased, and sclerosis | hardenability at the time of using an LED light source can be improved.

  Various arbitrary components can be added to the ultraviolet curable resin composition of the present invention as long as the effects of the present invention are not impaired. For example, antioxidants, UV absorbers, silane coupling agents, light stabilizers, anti-aging agents, antifoaming agents, leveling agents, antistatic agents, surfactants, storage stabilizers, thermal polymerization inhibitors, plasticizers, wetting A property improver or the like can be blended as necessary.

The ultraviolet curable resin composition of the present invention is produced as follows.
The composition of the present invention is obtained by charging the components (A) to (C) in a reaction vessel equipped with a stirrer and stirring at a liquid temperature of 20 to 60 ° C. until a uniform solution is obtained.

  The ultraviolet curable resin composition of the present invention exhibits particularly excellent curability when cured with light having a wavelength of 365 nm (ultraviolet rays), but in the same manner as in the case of ordinary photocurable resin compositions, It can also be cured by irradiation with visible light, electron beam or the like.

2. Adhesive for DVD The ultraviolet curable resin composition of the present invention includes plastics such as polycarbonate (PC) and polymethyl methacrylate (PMMA), metals such as gold, aluminum, silver and silicon, or mixtures thereof, and inorganic compounds such as glass. It shows a good adhesive force, and is suitable as an adhesive for optical disks.
Furthermore, the ultraviolet curable resin composition of the present invention exhibits particularly good curability and adhesiveness when an optical disk is bonded using an LED light source having a sharp emission spectrum at 365 nm, and the optical disk (DVD). Useful as an adhesive.

  The optical disk is bonded to the DVD adhesive of the present invention by, for example, filling the composition of the present invention between the adherends so that the thickness of the adhesive layer is 10 to 100 μm, It is carried out by curing by irradiating (ultraviolet rays) and firmly adhering the adherends together.

  The UV curable resin composition of the present invention is suitable for bonding films, resin plates, and the like that require optical properties as adhesives for polymer films, resin plates, etc., as well as for use as an adhesive for DVD. . Moreover, the ultraviolet curable resin composition of this invention has the outstanding adhesiveness, is excellent in heat resistance and water resistance, and is excellent also in moldability, and is useful as an adhesive composition. Especially suitable for laminating MS film and PET film on PVC sheet because it has excellent adhesion to glass and plastic substrate, especially MS film and PET film, but various other, building materials, packaging materials, It is also useful in the fields of printing materials, display materials, electrical / electronic component materials, optical component materials, liquid crystal panels and the like.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
Production Example 1: (A) Production of Urethane Acrylate A reaction vessel equipped with a stirrer was charged with 12.4 g of isophorone diisocyanate and 0.009 g of 2,6-di-t-butyl-p-cresol. 20.4 g of ethylene glycol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd.) was added as a diluent component, and these were ice-cooled to 10 ° C. while stirring. 0.03 g of dibutyltin dilaurate was added, 6.5 g of 2-hydroxyethyl acrylate (HEA Osaka Organic Chemical Industry Co., Ltd.) was added dropwise, and the mixture was stirred at 20 to 35 ° C. for 90 minutes. Subsequently, 18.2 g of polytetramethylene ether glycol (PTMG650: Hodogaya Chemical Co., Ltd.) having a molecular weight of 650 was added and reacted at 50 to 60 ° C. until the residual isocyanate amount was 0.02% or less. -1) was obtained.

Example 1: Production of UV curable resin composition A reaction vessel equipped with a stirrer was charged with a compound at a mixing ratio (parts by mass) shown in Table 1, and stirred at a liquid temperature of 50 ° C until a uniform solution was obtained. A curable resin composition was obtained.

Examples 2 to 4 and Comparative Example 1
A resin composition was obtained in the same manner as in Example 1 except that each component was blended in the ratio shown in Table 1 below.

The resin composition obtained was measured for light absorption at 365 nm (%) to evaluate curability. The evaluation results of the compositions of Examples and Comparative Examples are shown in Table 1 below.
The light absorption rate measurement method and the curability evaluation method are as follows.

<Measurement Method of Light Absorption Rate (%) at 365 nm>
A sample obtained by applying each resin composition to a quartz substrate with a thickness of 50 μm using a spin coater was used as a sample, and a quartz plate not coated on the reference side was placed, and a transmittance (%) of 365 nm was obtained by UV-visible spectrophotometry. Measured with a total (manufactured by Hitachi; U-3410). From the obtained transmittance,
Absorptivity (%) = 100−transmittance was determined.

<Evaluation method of curability>
Each resin composition was applied to an Al-deposited PC substrate with a thickness of 50 μm using a spin coater, and the PC substrate was placed thereon. Subsequently, light was irradiated from the PC substrate side using an LED lamp having a wavelength distribution having an emission peak at 365 nm, and the two substrates were bonded together.
For the evaluation of curability, the interface between the Al vapor-deposited PC substrate and the cured resin is removed with a cutter knife,
The presence or absence of tack on the surface of the cured resin was examined with a finger to determine curability. Judgment criteria were ◎ when there was no tack on the entire surface including the end face, ○ when the end face had tack but no tack at other locations, and x when tacked on the entire surface.

Details of the compounds of component (B) and component (C) in Table 1 are as follows.
Ingredient (B):
Epoxy diacrylate: Showa Polymer Co., Ltd., VR77
4-hydroxybutyl acrylate: Osaka Organic Chemical Industry Co., Ltd. Ethylene glycol diacrylate: Kyoei Chemical Co., Ltd. Component (C):
2,4,6-trimethylbenzoyldiphenylphosphine oxide: manufactured by BASF, Lucirin TPO
2-methyl-1- [4-methylthiophenyl] -2-morpholinopropan-1-one: Irgacure 907 manufactured by Ciba Specialty Chemicals
2-Benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1: Irgacure 369 manufactured by Ciba Specialty Chemicals
Other initiators:
Benzyldimethyl ketal: Irgacure 651, manufactured by Ciba Specialty Chemicals
2-hydroxy-2-methyl-1-phenylpropan-1-one: Caro Specialty Chemicals, Darocur 1173

  From the results of Table 1, in Examples containing a polymerization initiator (component (C)) having a large light absorption rate at 365 nm, the light absorption rate at 365 nm of the resin composition was as extremely high as 23 to 60%, and the curability was high. It turns out that it is also favorable.

  The ultraviolet curable resin composition of the present invention is an adhesive such as a polymer film and a resin plate, and is particularly suitable for bonding a film and a resin plate that require optical properties. Moreover, the ultraviolet curable resin composition of this invention has the outstanding adhesiveness, is excellent in heat resistance and water resistance, and is excellent also in moldability, and is useful as an adhesive composition. It is particularly suitable for laminating MS film and PET film on PVC sheet because it has excellent adhesion to glass and plastic substrates, especially MS film and PET film. It is also useful in the fields of printing materials, display materials, electrical / electronic component materials, optical component materials, liquid crystal panels and the like.

The ultraviolet curable resin composition of the present invention is particularly useful as a photocurable adhesive used when an optical disk (DVD) is bonded using an LED light source having a sharp emission spectrum at 365 nm.

Claims (3)

(A) at least one diol component selected from the group consisting of polypropylene glycol, polybutylene glycol, a copolymer of 1,2-butylene oxide and ethylene oxide, and a copolymer of propylene oxide and ethylene oxide, a diisocyanate, and a hydroxyl group A urethane (meth) acrylate obtained from a contained (meth) acrylate, and (B) a radical polymerizable compound,
(C) As a photopolymerization initiator, 0.1-15% by mass of only 0.1% by mass of a photopolymerization initiator having an absorbance at 365 nm (optical path length of 1 cm) of 0.2% or more. The ultraviolet curable resin composition which contains in the ratio.   The photopolymerization initiator (C) is 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-methyl-1- [4-methylthiophenyl] -2-morpholinopropan-1-one and 2-benzyl-2. The ultraviolet curable resin composition according to claim 1, which is composed of one or more selected from the group consisting of -dimethylamino-1- (4-morpholinophenyl) butanone-1. An adhesive for DVD (digital video disk or digital versatile disk) comprising the ultraviolet curable resin composition according to claim 1 or 2.