JP2017128634A - Ultraviolet curable resin composition and laminate - Google Patents

Abstract

[PROBLEMS] To provide an ultraviolet curable resin composition capable of forming a cured coating film having good curability on a paper substrate and having low viscosity, good bending resistance, and good blocking resistance. Bendability should be compatible with other performances (curing speed, leveling during coating, wear resistance, blocking resistance, etc.). An ultraviolet curable resin composition for forming a coat layer for protecting a paper base material having a printed layer on at least a part of a surface, wherein the urethane acrylate resin represented by the general formula (1) ( A), a nitrogen atom-containing acrylic monomer (B) capable of forming a homopolymer having a glass transition temperature of 80 ° C. or higher and 160 ° C. or lower, an acrylic monomer (C) having a surface tension of 20 to 35 dyn / cm, and a photopolymerization initiator ( An ultraviolet curable resin composition containing D) and having a cured film having a tensile elongation percentage of 5% to 100% according to a method according to JIS-K-7161. [Selection figure] None

Description

The present invention relates to an ultraviolet curable resin composition capable of forming a cured coating film having good ultraviolet curability when applied to a paper substrate, low viscosity, and good bending resistance, blocking resistance and the like.

Conventionally, as resin compositions for paper coating, two-component reaction type thermosetting resins such as solvent-based polymer resins, aqueous or emulsion resins, and photocurable resins are known, and these are water or organic resins. Since it contains a solvent, a drying process and a heat reaction process are required after coating, the productivity of coated paper is low, and organic solvents are undesirable from the viewpoints of air pollution, regulations in the Fire Service Act, occupational health, etc. was there.

Therefore, as a coating resin composition that does not contain an organic solvent and has good workability, a photocurable vinyl oligomer using a reactive diluent, a photopolymerizable monomer, and a photopolymerization initiator are used as constituents. A curable resin composition is disclosed (Patent Document 1). However, although these workability and handling properties are good, the curability and various physical properties of the cured coating film are not sufficient.

In a package using a paper substrate, printing on the surface of the substrate is performed by gravure printing, flexographic printing, UV flexographic printing, offset printing, UV offset printing, etc. A surface coat layer is provided for the purpose of protecting the material surface. A laminate composed of such a paper base material, a printing layer, and a surface coat layer is formed by being folded into a box state, but the ultraviolet curable resin composition mainly used for the surface coat layer is insufficient in flexibility, Cracks occurred in the bent part. In order to improve this, there is an example in which polystyrene-acrylic resin is used as an inert resin and improvement is made with a mixture of this and a monofunctional or polyfunctional monomer (Patent Document 2). However, the required bendability is very high, and if a monomer with a high glass transition temperature is used, it will crack, and if a monomer with a low glass transition temperature is used, bendability will be obtained, but other physical properties (curability and (Blocking resistance) cannot be achieved at the same time, leaving problems.

On the other hand, urethane acrylate oligomers are used as active energy ray-curable resins for other applications (such as coating agents for plastics) (Patent Documents 3 and 4). Among them, those having an isocyanurate skeleton have hardness, A coating excellent in strength, solvent resistance, and wear resistance is provided (Patent Documents 5 and 6).

However, these urethane acrylate oligomers having an isocyanurate skeleton are excellent in various performances (scratch resistance, stain resistance, solvent resistance, abrasion resistance, flex resistance). Alternatively, the viscosity is too high to be used for printing. Therefore, there is a method to balance the performance as a mixed composition by selecting a reactive diluent, but none of the conventional techniques satisfy the performance as an “ultraviolet curable composition for paper substrates”. It was.

JP-A-3-252460 Japanese Patent Laid-Open No. 10-298895 WO2007 / 046428 JP-A-6-175276 JP-A-2-9614 JP-A-2-274713

It is an ultraviolet curable resin composition that has good curability on a paper substrate and can form a cured coating film with low viscosity, good folding resistance, and good blocking resistance. , And other performances (curing speed, leveling during coating, wear resistance, blocking resistance, etc.).

As a result of intensive studies on the above problems, the present inventor has found that the problem can be solved by using the ultraviolet curable resin composition described below, and has reached the present invention.

The present invention is an ultraviolet curable resin composition for forming a coating layer that protects a paper substrate having a printed layer on at least a part of its surface, and is a urethane acrylate resin represented by the following general formula (1) (A), a nitrogen atom-containing acrylic monomer (B) capable of forming a homopolymer having a glass transition temperature of 80 ° C. or higher and 160 ° C. or lower, an acrylic monomer (C) having a surface tension of 20 to 35 dyn / cm (provided that the monomer (B ), And a photopolymerization initiator (D), and the cured film has a tensile elongation of 5% to 100% according to JIS-K-7161. Type resin composition.
General formula (1)

(Wherein R ¹ , R ² and R ³ represent an alkylene group having 10 or less carbon atoms, a divalent organic residue having a substituted or unsubstituted cyclohexylene group, a substituted or unsubstituted phenylene group, and R ⁴ Represents a caprolactone-modified (meth) acryloyl group (a-1) and / or a monovalent organic residue represented by the general formula (2).
General formula (2)

_{^{CH 2 = CR 5 -COO-R}} 6 -O-

(In the formula, R ⁵ represents a hydrogen atom or a methyl group, and R ⁶ represents an alkylene group having 10 or less carbon atoms.)

The present invention also relates to the ultraviolet curable resin composition, wherein the caprolactone-modified (meth) acryloyl group (a-1) has a structure represented by the following general formula (3).
General formula (3)

_{^{CH 2 = CR 5 -COO-R}} 6 -O- (CO-C 5 H 10 -O) n -

(In the formula, n represents an integer of 1 to 6.)

In the present invention, the nitrogen atom-containing acrylic monomer (B) capable of forming a homopolymer having a glass transition temperature of 80 ° C. to 160 ° C. is (meth) acryloylmorpholine, dimethyl (meth) acrylamide, N, N-dimethyl. The ultraviolet curable resin composition, which is at least one selected from aminopropyl (meth) acrylamide and N- (meth) acryloyloxyethyl hexahydrophthalimide. About.

The present invention also relates to the ultraviolet curable resin composition, wherein the photopolymerization initiator (D) contains a benzophenone photopolymerization initiator (d-1).

The present invention also includes a urethane acrylate resin (A), a nitrogen atom-containing acrylic monomer (B) capable of forming a homopolymer having a glass transition temperature of 80 ° C. to 160 ° C., an acrylic monomer having a surface tension of 20 to 35 dyn / cm ( C), the ratio by weight (A) / (B) / (C) is 60% to 40% / 55% to 35% / 10% to 1% (however, the sum of (A) to (C)) Is 100 wt%). The present invention relates to the ultraviolet curable resin composition.

Moreover, this invention relates to the laminated body which has a printing layer and the coating layer formed from the said ultraviolet curable resin composition on a paper base material.

It is an ultraviolet curable resin composition that has good curability on a paper substrate and can form a cured coating film with low viscosity, good folding resistance, and good blocking resistance. In addition, it was possible to provide an ultraviolet curable resin composition compatible with other performances (curing speed, leveling property during coating, wear resistance, blocking resistance, etc.).

Embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention does not exceed the gist thereof. The content is not limited.

The ultraviolet curable resin composition of the present invention is an ultraviolet curable resin composition for forming a coating layer for protecting a paper substrate having a printed layer on at least a part of its surface, and is represented by the following general formula (1) Urethane atom acrylate resin (A), a nitrogen atom-containing acrylic monomer (B) capable of forming a homopolymer having a glass transition temperature of 80 ° C. or higher and 160 ° C. or lower, an acrylic monomer (C) having a surface tension of 20 to 35 dyn / cm ) And a photopolymerization initiator (D), and the tensile elongation of the cured film according to JIS-K-7161 is 5% to 100%.
General formula (1)

(Wherein R ¹ , R ² and R ³ represent an alkylene group having 10 or less carbon atoms, a divalent organic residue having a substituted or unsubstituted cyclohexylene group, a substituted or unsubstituted phenylene group, and R ⁴ Represents a caprolactone-modified (meth) acryloyl group (a-1) and / or a monovalent organic residue represented by the general formula (2).
General formula (2)

_{^{CH 2 = CR 5 -COO-R}} 6 -O-

(In the formula, R ⁵ represents a hydrogen atom or a methyl group, and R ⁶ represents an alkylene group having 10 or less carbon atoms.)

<Urethane acrylate resin (A)>
The urethane acrylate resin (A) represented by the above general formula (1) is prepared by adding a caprolactone-modified hydroxyl-containing acrylate and / or hydroxyalkyl acrylate to a trimer of a diisocyanate compound represented by the following general formula (4). CH ₂ = CR ⁵ —COO—R ⁶ —O—H).
General formula (4)

Examples of the diisocyanate compound for forming the compound represented by the general formula (4) include 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylate. Range isocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4 ' -Diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, methylcyclohexane diisocyanate, m-tetramethylxyl Down diisocyanate and the like as a typical example. These can be used alone or in admixture of two or more. Of these, tolylene diisocyanate, hexamethylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, and isophorone diisocyanate are preferable.

The alkylene group having 10 or less carbon atoms in the general formula (1) is not particularly limited as long as it is a residue obtained by removing the isocyanate group from the diisocyanate compound. For example, ethylene group, propylene group, butylene group, pentylene group, hexamethylene Represents a group, an octylene group or the like, and may have a branched structure. Examples of the divalent organic residue having a substituted or unsubstituted cyclohexylene group include a cyclohexylene group, an isoholonylene group, and a bismethylenecyclohexane group. A substituted or unsubstituted phenylene group includes, for example, phenylene. Group, tolylene group and the like.
For example, tolylene diisocyanate, hexamethylene diisocyanate, 1,3-bis (isocyanate methyl) cyclohexane, and isophorone diisocyanate are trimers, so that a tolylene group, a hexamethylene group, a bismethylenecyclohexane group, and an isoholonylene group are R ¹ to It can be introduced into R ^3.

In the following description, (meth) acryl or (meth) acrylate means methacryl and acryl, methacrylate and acrylate, respectively. (Meth) acryloyl means methacryloyl and acryloyl.

The present invention only needs to satisfy the configuration, and is not limited to the effect, but the isocyanurate structure in the general formula (1) functions as a tough and strong hard segment. On the other hand, the caprolactone-modified (meth) acryloyl group (a-1) and the monovalent organic residue represented by the general formula (2) have a crosslinking function at the acrylate site, and R ⁶ alkylene group or R ⁴ The modified caprolactone structure in 作用 acts as a soft segment. Therefore, the compound represented by the general formula (1) becomes a compound having both hardness and flexibility after UV curing. In particular, the modified caprolactone structure is flexible and has a good elastic modulus and can be suitably used.

Examples of the hydroxyalkyl acrylate constituting the monovalent organic residue represented by the general formula (2) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and (meth) acrylic acid. 3-hydroxypropyl, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, (meth) acrylic acid Examples include 8-hydroxyoctyl. Among them, those having an alkyl group having 2 to 10 carbon atoms in R ⁶ are preferable, and in the above range, a cured film having a good balance between hardness and flexibility can be obtained. When the carbon number is greater than 10, a brittle cured film is obtained.

The caprolactone-modified hydroxyl group-containing acrylate constituting the caprolactone-modified (meth) acryloyl group (a-1) can be obtained by addition polymerization of ε-caprolactone to an acrylate having a hydroxyl group, and is known as an acrylate having a hydroxyl group Are appropriately selected, and include the above-mentioned hydroxyalkyl acrylate, glycol monoacrylate such as polyethylene glycol monoacrylate, polypropylene glycol monoacrylate, 1,4-cyclohexanedimethanol monoacrylate, etc. It is done.

The (meth) acryloyl group (a-1) is preferably a structure represented by the general formula (3).
General formula (3)

_{^{CH 2 = CR 5 -COO-R}} 6 -O- (CO-C 5 H 10 -O) n -

(In the formula, n represents an integer of 1 to 6.)

The caprolactone-modified hydroxyl group-containing acrylate constituting the group represented by the general formula (3) can be obtained, for example, by a method such as ring-opening addition polymerization of ε-caprolactone to the hydroxyalkyl acrylate. Specific examples include trade name Plaxel FA1, Plaxel FA2D, Plaxel FA5 (manufactured by Daicel Chemical Industries, Ltd.) and the like. Preferably, the average number n of the number of moles of ring-opening addition of ε-caprolactone per mole of the hydroxyalkyl acrylate monomer is 1 to 6, and when the number of moles added is within this range, the formula (1) In addition to the hardness derived from the isocyanurate structure, the flexibility and elasticity derived from the caprolactone chain are added, so the resistance (floating) of the laminate formed on the paper substrate, which is the subject of the present invention, , Cracks) are greatly improved.

The method for producing the urethane acrylate resin (A) is not particularly limited, and is usually an isocyanate trimer compound represented by the general formula (4) and a caprolactone-modified hydroxyalkyl acrylate and / or hydroxyalkyl acrylate. A method of charging and reacting one kind or two or more kinds at the same time may be employed. The mixing ratio is preferably such that the total number of moles of the acrylate is 3 moles relative to 1 mole of the formula (4), but the excess acrylate compound remains unreacted even when it exceeds 3 moles. Since it exists in the reaction mixture together with the target product and acts as a reactive diluent for the photocurable resin composition, an excess of an acrylate compound may be used as necessary. The reaction may be performed under a nitrogen or dry air atmosphere with stirring at a liquid temperature of 50 ° C. to 120 ° C. for 2 to 8 hours.

Moreover, you may use a urethanization catalyst as needed. Examples of urethanization catalysts include nitrogen-containing compounds such as triethylamine, triethylenediamine, and N-methylmorpholine, metal salts such as potassium acetate, zinc stearate, and tin octylate, and organometallic compounds such as dibutyltin laurate. can do. The amount used is preferably 0.02 to 0.05 parts by weight with respect to 100 parts by weight of the total charge. Usually, the reaction is carried out under heating, but it is preferable to take mild heating conditions of about 60 to 100 ° C. The reaction time is usually about 2 to 6 hours. Completion of the reaction can be easily confirmed by quantifying the isocyanate residue by IR spectrum.

Moreover, you may mix | blend a polymerization inhibitor at the time of the said urethane reaction. In the state of being heated and stirred as in the above urethane reaction, it is performed in an air atmosphere so that the acrylic group does not cause an initiation reaction, but it is easy to polymerize when the temperature is locally high or the viscosity is high. The use of a polymerization inhibitor is necessary. Typical examples of the polymerization inhibitor are hydroquinone derivatives and phenol derivatives, which are used in a resin in an amount of about 100 to 1000 ppm.

<Acrylic monomer (B)>
In the ultraviolet curable resin composition of the present invention, the nitrogen atom-containing acrylic monomer (B) (hereinafter referred to as acrylic monomer (B)) capable of forming a homopolymer having a glass transition temperature of 80 ° C. or higher and 160 ° C. or lower may be described. .) And urethane acrylate resin (A) are used in combination to improve hardness and curability and increase the strength of the cured coating. If the monomer has a glass transition temperature of less than 80 ° C., the desired hardness cannot be obtained, and the monomer that forms a homopolymer having a glass transition temperature higher than 160 ° C. is hard but not flexible, resulting in a brittle cured film. End up. More preferably, it is a nitrogen-containing acrylic monomer capable of forming a homopolymer having a glass transition temperature of 100 to 160 ° C.

Examples of the acrylic monomer (B) include (meth) acrylamide, dimethyl (meth) acrylamide, diethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, and N, N-dimethylaminopropyl (meth) acrylamide. N, N-dimethylaminopropyl (meth) acrylamide methyl chloride quaternary salt, (meth) acryloylmorpholine, isopropyl (meth) acrylamide, N- (meth) acryloyloxyethyl hexahydrophthalimide, hydroxyethyl (meth) acrylamide, etc. Among them, (meth) acryloylmorpholine, dimethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, and N- (meth) acryloyloxyethylhexahi are preferable. And at least one selected from Rofutaruimido, still more preferably (meth) acryloyl morpholine. You may use these individually or in combination of 2 or more types.

<Acrylic monomer (C)>
In the ultraviolet curable resin composition of the present invention, an acrylic monomer (C) having a surface tension of 20 to 35 dyn / cm (hereinafter sometimes referred to as an acrylic monomer (C)) is used. The surface tension here is the surface tension when the monomer is in a liquid state at 25 ° C. When the urethane acrylate resin (A) and the acrylic monomer (B) are used, for example, when acryloylmorpholine is used as the acrylic monomer (B), the surface tension of the compound is as high as 44.5 dyn / cm. When printing or coating on the material, the wet spread (leveling property) is poor and the film has a rough surface. Here, by using a low acrylic monomer (C) having a surface tension of 20 to 35 dyn / cm, printability / leveling properties and smoothness after coating are greatly improved. If the surface tension of the acrylic monomer (C) is lower than 20 dyn / cm, the ultraviolet curable resin composition becomes too low in viscosity, and troubles such as bleeding on the paper substrate during printing occur. On the other hand, when the surface tension is higher than 35 dyn / cm, the wettability is poor, and problems such as leveling failure during printing are caused. The surface tension of the acrylic monomer (C) is more preferably 25 to 30 dyn / cm from the viewpoint of improving leveling properties.

Methods for measuring the surface tension of acrylic monomer (C) include Wilhelmy method (plate method, vertical plate method), du Nouy method (ring method, ring method), hanging drop method (pendant drop method), maximum bubble pressure method The contact angle is measured and calculated from Young's equation. Any method may be used, but the du Nouy method (ring method or ring method) is preferred.

Examples of acrylic monomer (C) include, but are not limited to, octyl acrylate, decyl acrylate, (3-ethyloxetane-3-yl) methyl acrylate, trimethylcyclohexyl acrylate, isodecyl acrylate, isobornyl acrylate, isononyl acrylate , Isooctyl acrylate, isostearyl acrylate, lauryl acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate, and the like. Among these, acrylates having a linear or branched alkyl chain are preferred, such as lauryl acrylate, isodecyl acrylate, isooctyl acrylate, isodecyl acrylate, and isostearyl acrylate, and two or more of them may be used in combination.

<Photopolymerization initiator (D)>
Moreover, the ultraviolet curable resin composition of this invention contains a photoinitiator (D). The photopolymerization initiator (D) generates radicals by light irradiation, heating, etc., and initiates the crosslinking reaction and polymerization reaction of the acrylate groups of the urethane acrylate resin (A), acrylic monomer (B), and acrylic monomer (C). Let The photopolymerization initiator (D) is preferably used in an amount of 3 to 20% by weight in 100% by weight of the ultraviolet curable resin composition. More preferably, it is 5 to 15% by weight.

Examples of the photopolymerization initiator include acetophenone photopolymerization initiators such as 4-phenoxydichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4 -Isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 2-methyl- Examples include acetophenone photopolymerization initiators such as [4- (methylthio) phenyl] -2-morpholino-1-propanone and 2,2-dimethoxy-2-phenylacetophenone.

Examples of the alkylphenone photopolymerization initiator include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, and 2-hydroxy-2-methyl-1-phenyl-propane. -1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- {4- [4- (2 -Hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2- Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2- (dimethylamino) -2-[(4-methylphenyl) methyl]- - [4- (4-morpholinyl) phenyl] -1-butanone, and the like.

Examples of the benzoin photopolymerization initiator include benzoin, benzoin methyl ether, benzoin isoethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether.

Examples of the benzophenone photopolymerization initiator (d-1) include benzophenone, 4-methylbenzophenone, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone, methyl-o-benzoylbenzoate Benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4′-methyldiphenyl sulfide, 3,3-dimethyl-4-methoxybenzophenone, and the like. Of these, 4-methylbenzophenone is preferable.

As thioxanthone photopolymerization initiators, thioxanthone, 2-chlorothioxanthone, 2,4-dichlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 2,4-diisopropyl Examples include thioxanthone.

Examples of the anthraquinone photopolymerization initiator include α-acyloxime ester, benzyl, methylbenzoylformate (“Biacure 55”), 2-ethylanthraquinone, and the like.

Examples of acylphosphine oxide photopolymerization initiators include 2,4,6-trimethylbenzoyldiphenylphosphine oxide (“Lucirin TPO”), bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (“IRGACURE819”) and the like. Is mentioned.

As the photopolymerization initiator (D), it is possible to achieve both excellent flexibility and elastic modulus, and to prevent discoloration of the coating layer over time, and with the specific urethane acrylate and acrylic monomer used in the present invention. From the viewpoint of improving compatibility and curability, the following benzophenone-based photopolymerization initiator (d-1) is preferred, and one or more kinds may be used in combination.
<Ultraviolet curable resin composition>

In order to solve the problems of the present invention, the cured film obtained using the ultraviolet curable resin composition of the present invention has a tensile elongation of 5% to 100% according to a method according to JIS-K-7161. is there. The tensile elongation is due to the elastic modulus, and if the tensile elongation is in this range, it indicates that there are few cracks and floating at the time of folding when laminated on a paper substrate, and it can follow the bending stress. If the tensile elongation is less than 5%, whitening, cracking, and floatation become prominent when the laminate on the paper substrate is folded, and if it is more than 100%, the cured film itself is too soft and hardness and blocking resistance decrease. To do.

Furthermore, the tensile elongation is more preferably 10% to 70%. A cured film in this range reduces whitening, cracking, and float when the laminate on the paper substrate is folded, and at the same time achieves a high level of hardness, blocking resistance, scratch resistance, leveling, and smoothness. Is possible. For that purpose, the urethane acrylate resin (A), the nitrogen atom-containing acrylic monomer (B), and the acrylic monomer (C) in a weight percentage (A) / (B) / (C) of 60% to 40% / 55% to 35% / 10% to 1% (however, the total of (A) to (C) is 100% by weight).
Urethane acrylate resin (A) has high elastic modulus and flexibility, nitrogen atom-containing acrylic monomer (B) cure speed and hardness, acrylic monomer (C) leveling during coating and printing, and compatibility with other components Take on. A more preferable range of the urethane acrylate resin (A) / acrylic monomer (B) / acrylic monomer (C) is 55% to 45% / 50% to 40% / 5% to 1%.

Further, in 100% by weight of the ultraviolet curable resin composition of the present invention, the total of the urethane acrylate resin (A), the nitrogen atom-containing acrylic monomer (B) and the acrylic monomer (C) is preferably 70% or more and 99% or less. Preferably they are 75% or more and 95% or less.

(Medium)
The ultraviolet curable resin composition of the present invention preferably does not use an organic solvent and / or water as a medium. The term “medium” as used herein does not correspond to a very small amount of an organic solvent or water derived from a raw material used, and means a medium that is intentionally used for the purpose of dilution, low viscosity, or the like. By not using organic solvent, it contributes to environmental conservation by preventing scattering of organic solvent (low VOC) and power saving by reducing drying process. An organic solvent or water mainly has an effect of decreasing the viscosity, but in the ultraviolet curable resin composition of the present invention, the acrylic monomer (B) and the acrylic monomer (C) function as a reactive diluent.

In the ultraviolet curable resin composition of the present invention, when an organic solvent is unavoidably used, it is preferably used to the minimum as long as the coating performance and the printing / coating performance are not hindered. As the organic solvent that can be used, known organic solvents can be used, for example, alcohol solvents such as methanol, ethanol, and isopropanol, ester solvents such as ethyl acetate and propyl acetate, glycol ether solvents such as propylene glycol monomethyl ether, and acetone. And ketone solvents such as methyl ethyl ketone, aromatic solvents such as toluene and xylene, and mixtures thereof.

The preferred viscosity of the ultraviolet curable resin composition of the present invention is 100 to 1000 mPa · s / 25 ° C., more preferably 200 to 700 mPa · s / 25 ° C. with a B-type viscometer. Viscosity suitable for processing.

(Photosensitizer)
Moreover, it is preferable that the ultraviolet curable resin composition of this invention uses an amine photosensitizer as a photosensitizer. Specific examples of the amine photosensitizer include, for example, aliphatic amines such as trimethylamine, triethylamine, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, aniline, N-methylaniline, and N, N-dimethyl. Examples include aromatic amines such as aniline, amine-based (meth) acrylates such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, and acryloylmorpholine, amine-based polyester acrylates, and amine-based acrylate oligomers. Of these, N-methyldiethanolamine is preferably used because of particularly good compatibility with the composition of the present invention and good photosensitization. The amine photosensitizer is used in the range of 1 to 20 parts by weight, more preferably in the range of 2 to 5 parts by weight, out of 100 parts by weight of the total photocurable composition.

(Other acrylic monomers)
In addition, an acrylic monomer may be included as long as the effect of the ultraviolet curable resin composition of the present invention is not impaired.

Other acrylic monomers include, for example, β-carboxyethyl (meth) acrylate, ethoxylated phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, EO-modified phenol (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, methoxytri Examples include ethylene glycol (meth) acrylate.

In addition, other acrylic monomers may have a hydroxyl group, for example, polyethylene glycol mono (meth) acrylic acid ester, polypropylene glycol mono (meth) acrylic acid ester, 1,4-cyclohexanedimethanol mono (meth) acrylic acid ester. And glycol mono (meth) acrylic acid esters, hydroxyethyl (meth) acrylamide and the like.

In addition, the acrylic monomer may have a functional group other than a hydroxyl group, and examples of the functional group include a carboxyl group, an amide bond group, an amino group, and an alkylene oxide group.

Other acrylic monomers containing a carboxyl group include (meth) acrylic acid, monohydroxyethyl phthalate (meth) acrylate, p-carboxybenzyl (meth) acrylate, ethylene oxide modification (added moles: 2) -18) phthalic acid (meth) acrylic acid ester, phthalic acid monohydroxypropyl (meth) acrylic acid ester, succinic acid monohydroxyethyl (meth) acrylic acid ester, (meth) acrylic acid β-carboxyethyl, (meth) acrylic Examples include the acid 2- (4-benzoyl-3-hydroxyphenoxy) ethyl, maleic acid, monoethylmaleic acid, itaconic acid, citraconic acid, and fumaric acid.

Other acrylic monomers containing amino groups include, for example, monomethylaminoethyl (meth) acrylate, monoethylaminoethyl (meth) acrylate, monomethylaminopropyl (meth) acrylate, monoethylamino (meth) acrylate Examples include (meth) acrylic acid monoalkylamino esters such as propyl.

Other acrylic monomers may have a polyether structure. For example, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, ethoxypolyethylene glycol (meth) acrylic acid Examples include esters, methoxypolypropylene glycol (meth) acrylic acid esters, ethoxypolypropylene glycol (meth) acrylic acid esters, phenoxypolyethylene glycol (meth) acrylic acid esters, and phenoxypolypropylene glycol (meth) acrylic acid esters.

Other acrylic monomers may contain two acryloyl groups. For example, ethylene glycol di (meth) acrylate, hexamethylene glycol di (meth) acrylate, nonanediol di (meth) acrylate, decanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate , Tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) Acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene oxide modified bisphenol A type di (meth) acrylate, propylene oxide modified bisphenol A type di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,6-hexanediol ethylene oxide modified di (meth) acrylate, glycerin di ( (Meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, diethylene glycol diglycidyl ether di (meth) acrylate, diglycidyl phthalate di (meth) acrylate, hydroxypivalic acid modified neopentyl Glycol di (meth) acrylate, isocyanuric acid ethylene oxide modified diacrylate, 2- (meth) acryloyloxyethyl acid phosphate diester, etc. It is.

The ultraviolet curable resin composition of the present invention can appropriately include known additives as additives, and known additives such as leveling agents, polymerization inhibitors, and the like as necessary in the production of ultraviolet curable resin compositions, UV absorbers, light stabilizers, sensitizers other than amine photosensitizers, curing agents, plasticizers, wetting agents, adhesion aids, antifoaming agents, antistatic agents, trapping agents, antiblocking agents, wax components Silica particles, resin particles, preservatives, and the like can be used. Furthermore, oil, flame retardant, filler, stabilizer, reinforcing agent, matting agent, abrasive, organic fine particles, inorganic fine particles, polymer compounds (acrylic resin, polyester resin, polyurethane (urea) resin, vinyl chloride-acetic acid It is also possible to blend a vinyl copolymer resin or the like).

As the leveling agent, a known general leveling agent can be used as long as it has a wettability imparting action to the base material of the coating liquid and a surface tension reducing action. For example, a silicone-modified resin, a fluorine-modified resin, An alkyl-modified resin or the like can be used.

Examples of the polymerization inhibitor include p-benzoquinone, naphthoquinone, tolquinone, 2,5-diphenyl-p-benzoquinone, hydroquinone, 2,5-di-t-butylhydroquinone, methylhydroquinone, hydroquinone monomethyl ether, mono-t- Examples thereof include butyl hydroquinone, pt-butyl catechol, and p-methoxyphenol.

As said ultraviolet absorber, metal oxide microparticles | fine-particles, such as titanium dioxide, zinc oxide, iron oxide, cerium oxide, thallium oxide, lead oxide, a zirconium oxide, can be used as an inorganic type ultraviolet absorber, for example. Examples of organic UV absorbers include benzotriazole UV absorbers, triazine UV absorbers, benzoxazine UV absorbers, salicylic acid ester UV absorbers, diphenylmethanone UV absorbers, and 2-cyanopropenoic acid. Ester UV absorber, Anthranilate UV absorber, Cinnamic acid derivative UV absorber, Camphor derivative UV absorber, Benzalmalonate derivative UV absorber, Resorcinol UV absorber, Oxalinide UV absorber In addition, a coumarin derivative-based ultraviolet absorber or the like can be used. Of these, benzotriazole-based ultraviolet absorbers are preferred.

Examples of the benzotriazole ultraviolet absorber include 2- (2′-hydroxy-5′-t-octylphenyl) -benzotriazole, 2- (2′-hydroxy-5′-methylphenyl) -benzotriazole, 2, 2-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6 [(2H-benzotriazol-2-yl) phenol]], 2- (2H-benzotriazol-2-yl) -4 -(1,1,3,3-tetramethylbutyl) phenol, 2- [5-chloro (2H) -benzotriazol-2-yl] -4-methyl-6- (tert-butyl) phenol, etc. Can do. Of these, 2- (2'-hydroxy-5'-t-octylphenyl) -benzotriazole and 2- (2'-hydroxy-5'-methylphenyl) -benzotriazole are particularly preferable.

Examples of the triazine ultraviolet absorber include 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol, 2,4,6-tris- (Diisobutyl 4′-amino-benzalmalonate) -s-triazine, 4,6-tris (2-hydroxy-4-octyloxyphenyl) -1,3,5-triazine, 2- (2-hydroxy-4 -Octyloxyphenyl) -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2- (2,4-dihydroxyphenyl) -4,6-bis (2,4-dimethyl) Phenyl) -1,3,5-triazine, 2,4-bis (2-hydroxy-4-propyloxyphenyl) -6- (2,4-dimethylphenyl) -1,3,5-triazine, 2- ( 2-Hide Carboxymethyl-4-dodecyloxy-phenyl) -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine and the like.

Examples of the diphenylmethanone UV absorber include diphenylmethanone, methyldiphenylmethanone, 4-hydroxydiphenylmethanone, 4-methoxydiphenylmethanone, 4-octoxydiphenylmethanone, 4-decyloxydiphenylmethanone. 4-dodecyloxydiphenylmethanone, 4-benzyloxydiphenylmethanone, 4,2 ′, 4′-trihydroxydiphenylmethanone, 2′-hydroxy-4,4′-dimethoxydiphenylmethanone, 4- (2 -Ethylhexyloxy) -2-hydroxy-diphenylmethanone, methyl o-benzoylbenzoate, benzoin ethyl ether and the like.

Examples of the 2-cyanopropenoic acid ester ultraviolet absorber include ethyl α-cyano-β, β-diphenylpropenoic acid ester, isooctyl α-cyano-β, β-diphenylpropenoic acid ester, and the like.

Examples of the salicylic acid ester UV absorber include isocetyl salicylate, octyl salicylate, glycolic salicylate, and phenyl salicylate.

Examples of the anthranilate ultraviolet absorber include menthyl anthranilate.

Cinnamic acid derivative-based ultraviolet absorbers include, for example, ethylhexyl methoxycinnamate, isopropyl methoxycinnamate, isoamyl methoxycinnamate, diisopropylmethyl cinnamate, glyceryl-ethylhexanoate dimethoxycinnamate, methyl-α-carbomethoxycinnamate Methyl-α-cyano-β-methyl-p-methoxycinnamate and the like.

Examples of the camphor derivative ultraviolet absorber include benzylidene camphor, benzylidene camphor sulfonic acid, camphor benzalkonium methosulfate, terephthalylidene dicamphor sulfonic acid, polyacrylamide methyl benzylidene camphor, and the like.

Examples of the resorcinol-based ultraviolet absorber include dibenzoyl resorcinol, bis (4-tert-butylbenzoyl resorcinol), and the like.

Examples of the oxalinide ultraviolet absorber include 4,4′-di-octyloxyoxanilide, 2,2′-diethoxyoxyoxanilide, 2,2′-di-octyloxy-5,5′-. Di-tert-butyl oxanilide, 2,2'-di-dodecyloxy-5,5'-di-tert-butyl oxanilide, 2-ethoxy-2'-ethyl oxanilide, N, N'- Bis (3-dimethylaminopropyl) oxanilide, 2-ethoxy-5-tert-butyl-2'-ethoxy oxanilide, etc. are mentioned.

Examples of the coumarin derivative-based ultraviolet absorber include 7-hydroxycoumarin.

The light stabilizer captures radicals generated by photodegradation, for example, radical scavengers such as thiol-based, thioether-based, hindered amine-based compounds, and ultraviolet absorbers such as benzophenone-based and benzoate-based compounds, etc. These may be used alone or in combination of two or more. Especially, it is preferable to use a hindered amine type compound from a viewpoint which can improve compatibility and light stability more.

The light stabilizer is a compound having an effect of reducing auto-oxidative decomposition due to radicals generated by light energy and suppressing resin degradation. As the light stabilizer, a hindered amine compound (abbreviated as “HALS”) or the like can be used. Examples of the hindered amine system include a reaction product of cyclohexane and N-butyl peroxide 2,2,6,6-tetramethyl-4-piperidineamine-2,4,6-trichloro 1,3,5-triazine. Reaction product with 2-aminoethanol (trade name: Tinuvin 152 (manufactured by BASF Corporation)), bis (2,2,6,6-tetramethyl-1- (octyloxy) -4-piperidinyl decanoate ) Hindered amine compounds having an amino ether group such as ester (trade name: Tinuvin 123 (manufactured by BASF)), reaction product of 1,1-dimethylethyl hydroperoxide and octane, N-acetyl-3-dodecyl- 1- (2,2,6,6-tetramethyl-4-piperidinyl) pyrrolidine-2,5-dione (trade name: Hostavin 3058 ( N-acetyl hindered amine compounds such as Lariant Japan Co., Ltd.), bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate (trade name: Sanol LS765 (manufactured by BASF Japan Co., Ltd.)) ), Bis (1,2,2,6,6, -pentamethyl-4-piperidyl) {[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl} butyl malonate Tinuvin (registered trademark) 144 (manufactured by BASF Japan Ltd.)), dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol (trade name: Tinuvin (registered trademark)) ) 622LD (manufactured by BASF Japan Ltd.)), Probandioic acid [{4-methoxyphenyl} methylene] -bi (1,2,2,6,6-pentamethyl-4-piperidyl) ester (trade name: Hostavin (registered trademark) PR-31 (manufactured by Clariant Japan Co., Ltd.)) N-alkyl hindered amine compound bis (2, 2,6,6-tetramethyl-4-piperidyl) sebacate, methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, poly [{6- (1,1,3,3-tetramethyl Butyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetra Methyl-4-piperidyl) imino}], 2,2′-thiobis (4-t-octylphenolate) alkylamine nickel, dibutylamine, 1,3,5-triazine, N, N-bi (2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine, N- (2,2,6,6-tetramethyl-4-piperidyl) butylamine polycondensate, etc. Can be mentioned. Among them, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate are preferable.

Examples of sensitizers other than the amine photosensitizer include biphenyl, 1,4-dimethylnaphthalene, 9-fluorenone, fluorene, phenanthrene, triphenylene, anthracene, 9,10-diphenylanthracene, and 9,10-dimethoxy. Anthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, 9,10-dibutoxyanthracene, benzophenone, 4,4′-dimethoxybenzophenone, acetophenone, 4-methoxyacetophenone, benzaldehyde, etc. may be used it can.

As the curing agent, polyisocyanate compounds typified by tolylene diisocyanate, adducts derived from hexamethylene diisocyanate, and nurate, polyfunctional epoxy compounds, melamine compounds, metal chelates, etc. should be used. Can do.

Moreover, the ultraviolet curable resin composition of the present invention may contain other additives in addition to those described above. Examples of other additives include a thixotropic agent, a curing agent, a curing accelerator, a tackifier, a thermal stabilizer, a fluorescent brightening agent, a foaming agent, a thermoplastic resin, a thermosetting resin, a conductivity imparting agent, Moisture permeability improver, water repellent, hollow foam, crystal water-containing compound, flame retardant, water absorbent, hygroscopic agent, deodorant, foam stabilizer, antifungal agent, antialgae, hydrolysis inhibitor, organic and Inorganic water-soluble compounds and the like can be used.

The production method of the ultraviolet curable resin composition of the present invention includes a urethane acrylate resin (A), a nitrogen atom-containing acrylic monomer (B) capable of forming a homopolymer having a glass transition temperature of 80 ° C. or higher and 160 ° C. or lower, and surface tension. Can be produced by stirring the acrylic monomer (C) having a molecular weight of 20 to 35 dyn / cm and the photopolymerization initiator (D) with a disper or the like for about 30 minutes to 3 hours. In the case where mixing is difficult and viscosity is likely to be nonuniform, a roller mill, a ball mill, a pebble mill, an attritor, a sand mill, or the like may be used.

When the ultraviolet curable resin composition of the present invention contains bubbles or unexpectedly large particles, it is preferably removed by filtration or the like in order to reduce the quality of the printed matter. A conventionally well-known filter can be used.

<Laminated body>
The ultraviolet curable resin composition of the present invention is effectively used as a curable composition for coating film formation which is a coating layer (topcoat layer) on various paper substrates having a printed layer. Can protect the printed layer on the material, has good adhesion to the paper substrate or printed layer, or good anti-blocking properties between the coating layers, and is hardened with little cracking and peeling of the coated layer even when the paper substrate is folded. A laminate having excellent properties can be obtained.

The production method of the laminate of the present invention is not particularly limited, but preferably, the printing ink composition is printed on a paper substrate, dried or ultraviolet-cured to form a printed layer, and further the ultraviolet-cured of the present invention is formed thereon. It can be created by printing and ultraviolet curing the mold resin composition.

<Paper base material>
The paper base material used in the present invention is ordinary paper, cardboard, and the like, and there is no particular designation as the film thickness, but a film having a thickness of 0.2 mm to 1.0 mm can be used, and the printing surface may be corona-treated. . The surface of the paper substrate may be vapor-deposited with a metal such as aluminum for the purpose of imparting design properties, and surface coating with an acrylic resin, urethane resin, polyester resin, polyolefin resin or other resin. Further, surface treatment such as corona treatment may be applied. Examples thereof include coated cardboard and marie coated paper.

<Printing ink composition>
Examples of the printing ink composition include a gravure ink composition, a flexographic ink composition, an ultraviolet curable flexographic ink composition, an offset ink composition, an ultraviolet curable offset ink composition, and other ink compositions. An ink composition may be used. In particular, when the ultraviolet curable offset ink composition and the ultraviolet curable flexographic ink composition are laminated with an ultraviolet curable resin composition, the ultraviolet curing reaction occurs between the layers, so that the adhesion is improved. Therefore, an ultraviolet curable offset ink composition and an ultraviolet curable flexographic ink composition are more preferable.

The gravure ink composition, flexographic ink composition or offset ink composition is composed of a pigment, a binder, an additive, a solvent, water, or the like. Examples of the binder include fiber materials such as nitrocellulose, cellulose acetate propionate, Chlorinated polypropylene, vinyl chloride-vinyl acetate copolymer, polyester, acrylic, polyurethane and acrylic urethane, polyamide, polybutyral, cyclized rubber, chlorinated rubber, rosin modified phenolic resin, alkyd Resin system etc. are mentioned, and these may be used together as appropriate.
The ultraviolet curable offset ink composition and the ultraviolet curable flexographic ink composition include urethane acrylate resin, diallyl phthalate (DAP) resin, other inert resin having no double bond, and the like, and further contains a monomer. Examples of the monomer include monofunctional (meth) acrylic monomers, polyfunctional (meth) acrylic monomers, and other monomers, and it is preferable to include a trifunctional or higher polyfunctional (meth) acrylic monomer.

There is no restriction | limiting in particular as a pigment used for a printing ink composition, The organic and inorganic pigment currently used for general ink, a coating material, a recording agent, etc. can be used together. Organic pigments include azo, phthalocyanine, anthraquinone, perylene, perinone, quinacridone, thioindigo, dioxazine, isoindolinone, quinophthalone, azomethine azo, dictopyrrolopyrrole, isoindoline, etc. These pigments are mentioned. Further, although not limited to the following examples, for example, carmine 6B, lake red C, permanent red 2B, disazo yellow, pyrazolone orange, carmine FB, chromophthal yellow, chromophthal red, phthalocyanine blue, phthalocyanine green, dioxazine violet Quinacridone magenta, quinacridone red, indanthrone blue, pyrimidine yellow, thioindigo Bordeaux, thioindigo magenta, perylene red, perinone orange, isoindolinone yellow, aniline black, diketopyrrolopyrrole red, daylight fluorescent pigment, etc. Can be mentioned.

Examples of the white inorganic pigment as the pigment in the printing ink composition include titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, and silica. It is preferable to use titanium oxide for the pigment of the white ink in terms of coloring power, hiding power, chemical resistance, and weather resistance. From the viewpoint of printing performance, the titanium oxide is treated with silica and / or alumina and / or polyol. Those that have been subjected to are preferred.

Non-white inorganic pigments are not limited to the following examples, but include, for example, carbon black, aluminum powder, mica (mica), bronze powder, chrome vermillion, chrome lead, cadmium yellow, cadmium red, ultramarine, and bitumen. , Bengara, yellow iron oxide, iron black, titanium oxide, zinc oxide, etc., and aluminum is in the form of a powder or paste, but it is preferably used in the form of a paste from the viewpoint of handling and safety. Whether to use leafing is appropriately selected from the viewpoint of brightness and density.

Further, in the production of the printing ink composition used in the present invention, known additives as necessary, such as pigment derivatives, pigment dispersants, wetting agents, adhesion aids, leveling agents, antifoaming agents, antistatic agents, A trapping agent, an antiblocking agent, a wax component, silica particles, a polymerization inhibitor, a color separation inhibitor, and the like can be used.

<Lamination method>
As a printing method of the printing ink composition, a known method can be used. For example, a gravure printing method, a flexographic printing method, an offset printing method, a screen printing method, etc. are mentioned. The thickness of the ink layer is preferably 0.1 μm to 15 μm. If the thickness is less than 0.1 μm, ink coloring is insufficient, while if it exceeds 15 μm, the ink layer becomes brittle.
The printing ink composition may be any of an oil-based ink composition, a water-based ink composition, and an ultraviolet curable ink composition, and can be dried or ultraviolet-cured after printing to form a printed layer.

The coating method of the ultraviolet curable resin composition is not particularly limited. For example, spraying, showering, dipping, flow coating, gravure printing, flexographic printing, roll, spin, dispenser, ink jet printing, screen printing, etc. A wet coating method.

Examples of ultraviolet rays for curing the ultraviolet curable resin composition include deep ultraviolet rays, ultraviolet rays, and near ultraviolet rays. On the other hand, it is also possible to use an electron beam or a proton beam. In this case, it can be cured without using the photopolymerization initiator (D), but the curing rate, the availability of the irradiation device, the price, etc. To curing by ultraviolet irradiation.

As a method of curing by ultraviolet irradiation, using a high pressure mercury lamp that emits light in a wavelength range of 150 to 450 nm, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a chemical lamp, an electrodeless discharge lamp, an LED, etc. 30~5000mJ / cm ^2, may be preferably 100~1000mJ / cm ² irradiation. After the ultraviolet irradiation, heating can be performed as necessary to complete the curing.

As a film thickness (film thickness after curing) when applying the ultraviolet curable resin composition, it is usually preferably 1 to 80 μm, particularly 3 to 60 μm, more preferably 5 to 50 μm. . Within this range, there is no inhibition of curing, the ultraviolet irradiation time can be shortened, and the productivity is good.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these Examples. In the present invention, parts and% represent parts by weight and% by weight unless otherwise noted.
As the weight average molecular weight in the examples, GPC (gel permeation chromatography) “Shodex GPC System-21” manufactured by Showa Denko KK was used. GPC is liquid chromatography that separates and quantifies substances dissolved in a solvent based on the difference in molecular size. Tetrohydrofuran is used as a solvent, and the weight average molecular weight is determined in terms of polystyrene.

In this specification, the values described in the monomer catalog were used for the glass transition temperature of the homopolymer formed by the monomer (B) and the surface tension of the monomer (C). In addition to the catalog value, a value described in a document such as a polymer handbook can be used. When the value is unknown, a value obtained by measurement can be used.
Examples of the method for measuring the glass transition temperature include a method using differential scanning calorimetry (DSC), and examples of the method for measuring the surface tension include the du Nouy method (ring method, ring method). An automatic surface tension meter DY-300 manufactured by KK can be used.

[Synthesis Example 1]
Hexamethylene diisocyanate trimer (hereinafter referred to as “HDI isocyanurate”) in a 2 L separable four-necked flask equipped with a stirrer, thermometer, and condenser (Product name: Sumidur N3390, manufactured by Sumika Bayer Urethane Co., Ltd.) ), 500 parts (1.0 mole), ε-caprolactone-added hydroxyethyl acrylate (number of moles of ε-caprolactone added 1) (product name: Plaxel FA1, manufactured by Daicel Corporation), 684 parts (3 moles), p-methoxyphenol 1.184 Part (500 ppm) was added, stirred while feeding air, and reacted at 80 ° C. for 4 hours. After confirming the disappearance of the peak due to the isocyanate group in the IR spectrum and completing the reaction, the reaction mixture was cooled to 40 ° C. to obtain 1184 parts of a pale yellow liquid (UA1).

<Synthesis of ε-caprolactone-added polyethylene glycol monoacrylate (EO addition number 4)>
In a 1 L four-necked flask, 1 mol of polyethylene glycol monoacrylate (EO addition number 4) (Blenmer AE200 manufactured by NOF Co., Ltd.) was reacted with 5 mol of ε caprolactone for 5 hours in air bubbling at 80 ° C, and ε caprolactone was obtained. Addition polyethylene glycol monoacrylate (EO addition number 4, ε caprolactone addition number 5) was synthesized.

[Synthesis Examples 2 to 8]
In the same manner as in Synthesis Example 1, urethane acrylates (UA2 to UA8) were obtained using the raw materials and preparation ratios shown in Table 1. In addition, the abbreviation of a raw material is represented below.
<Diisocyanate trimer>
IPDI isocyanurate (3 amounts of isophorone diisocyanate)
<Ε caprolactone-added hydroxyethyl acrylate>
-Ε caprolactone addition mole number 2 (Product name: Plaxel FA2D manufactured by Daicel Corporation)
-Ε caprolactone addition mole number 5 (Product name: Plaxel FA5 manufactured by Daicel Corporation)

[Comparative Synthesis Examples 1 to 3]
By the same operations as in Synthesis Example 1 with the raw materials and preparation ratios shown in Table 1, urethane acrylates (UA9 to UA11) were obtained.

<Comparative Synthesis Example 4: Synthesis of Styrene-Acrylic Resin (SA1)>
The following was synthesized based on the examples described in JP-A-10-298895.
In a four-necked flask equipped with a thermometer, a dropping funnel, a stirrer, a condenser, and a temperature controller, 100 g of toluene was added and the temperature was raised to 110 ° C., then 72 g of styrene, 14 g of 2-ethylhexyl acrylate, 2-hydroxypropyl A mixture of 14 g of acrylate, 3 g of azobisisobutyronitrile and 4 g of 2,2′-azobis (2-methylbutyronitrile) was dropped into the flask over 5 hours for polymerization, and styrene-acrylic resin solution SA1. Got. (Solid content 50%, glass transition temperature: 44 ° C., weight average molecular weight 6200)

<Comparative Synthesis Example 5: Synthesis of Styrene-Acrylic Resin (SA2)>
The following was synthesized based on the examples described in JP-A-10-298895.
In a four-necked flask equipped with a thermometer, a dropping funnel, a stirrer, a condenser and a temperature controller, 100 g of toluene was added and the temperature was raised to 110 ° C., and then 77 g of styrene, 9 g of 2-ethylhexyl methacrylate, 2-hydroxypropyl A mixture of 12 g of methacrylate, 3 g of azobisisobutyronitrile and 4 g of 2,2′-azobis (2-methylbutyronitrile) was dropped into the flask over 5 hours for polymerization, and the styrene-acrylic resin solution SA2 Got. (Solid content 50%, glass transition temperature: 60 ° C., weight average molecular weight 6000)

(Example 1: Preparation of ultraviolet curable resin composition S1)
45 parts of urethane acrylate UA1, 40 parts of acryloylmorpholine, 3 parts of isostearyl acrylate, 10 parts of benzophenone and 2 parts of N-methyldiethanolamine are mixed and stirred with a disper for 30 minutes to obtain an ultraviolet curable resin composition S1. Obtained.

(Examples 2 to 17: Creation of ultraviolet curable resin compositions S2 to S17)
Ultraviolet curable resin compositions S2 to S17 were obtained in the same manner as in Example 1 with the blending ratios of the raw materials shown in Table 2-1.

(Comparative Examples 1 to 17: Creation of UV-curable resin compositions T to T17)
Ultraviolet curable resin compositions T to T17 were obtained in the same manner as in Example 1 with the blending ratios indicated for the raw materials shown in Table 2-2.

(Example 18)
<Coating of UV-curable resin composition S1>
In Example 1 on a paper base material on which a UV offset ink (FD Carton X Black M: manufactured by Toyo Ink Co., Ltd., including a trifunctional or higher polyfunctional (meth) acrylic monomer) was previously printed on coated cardboard. The obtained S1 was coated with a bar coater # 3 to a film thickness of 5.0 μm and cured under the condition of one 160 W / cm high-pressure mercury lamp, an irradiation distance of 10 cm and an integrated light quantity of 300 mj / cm ² . To obtain a laminate G1. The UV offset ink was printed using a simple color developing machine RI tester, printed so that the film thickness of FD Carton X ink M was 1.0 μm, one high-pressure mercury lamp, and an integrated light quantity of 100 mj / cm ^2. And cured.

(Examples 19 to 34)
By the same method as in Example 18, laminates G2 to G17 (Examples) were obtained using the ultraviolet curable resin compositions S2 to S17 described in Table 2-1.

(Comparative Examples 18-34)
By the same method as in Example 18, laminates H1 to H17 (comparative examples) were obtained using the ultraviolet curable resin compositions T1 to T17 described in Table 2-2. In addition, about Comparative Examples 29-34, the ultraviolet irradiation was performed after 30-second solvent drying in 80 degreeC oven.

(Examples 35-37)
S2, S3 and S7 obtained in Examples 2, 3 and 7 were each bar coater on a paper base on which gravure ink (Eco Color F92 Black: manufactured by Toyo Ink Co., Ltd.) was previously printed on coated cardboard. It was coated to a film thickness of 5.0 μm by dry stacking in # 3, and cured under the conditions of one 160 W / cm high-pressure mercury lamp, irradiation distance of 10 cm, and integrated light quantity of 300 mj / cm ² , and laminates G18 to G20 Got. The printing conditions for gravure ink were: Ecocolor F92 ink was diluted with a mixed solvent of toluene: methyl ethyl ketone = 1: 1 in Zaan cup # 3 for 15 seconds (25 ° C.), and engraved 175 line, solid plate of plate-type compressed was used. Printing was performed at a printing speed of 40 m / min with a small printing machine provided, and drying was performed at 70 ° C.

(Comparative Examples 35-37)
In Examples 35 to 37, laminates H18 to H20 were obtained in the same manner as in Examples 35 to 37 except that S2, S3, and S7 were changed to T12, T14, and T15 obtained in Comparative Examples 12, 14, and 15. It was.

For UV curable resin compositions S1 to S17 and T1 to T17, the viscosity at 25 ° C. (using a B-type viscometer), the laminates G1 to G20, and H1 to H20 are resistant to bending, curing speed (integrated light amount), leveling property, A friction resistance test, an anti-blocking test and the like were conducted and are shown in Table 3-1 and Table 3-2.

<Viscosity at 25 ° C>
Viscosity at 25 ° C. was measured with a B-type viscometer for the ultraviolet curable resin compositions S1 to S17 and T1 to T17. The determination criteria are as follows.
-A numerical value of 100 to 1000 mPa · s has no practical problem, and a numerical value of 200 to 700 mPa · s is preferred because of low viscosity.
-If the viscosity is less than 100 mPa · s, bleeding into the paper substrate may occur, which is not preferable.
-When viscosity exceeds 1000 mPa * s, since viscosity is too high, coating is difficult.

<Bending resistance>
The laminates G1 to G20 and H1 to H20 (accumulated light amount 300 mj / cm ² ) are folded back 180 ° toward the non-coating surface and further bent 180 ° at the same site in the coating surface direction, and the fold line portion is evaluated visually. did.
○ ・ ・ ・ ・ ・ Break at the fold line and no whitening.
○ △ ・ ・ ・ ・ Fracture of the fold line part is less than 20% and slightly whitened.
Δ ······················· 20 to 60% of cracks in the fold line part, all whitened.
Δ × ······· 60 to 80% of cracks in the fold line portion, all whitened.
× ··········· A range where there is no practical problem in the circles where the bend line portion is 100% cracked and the pieces fall off.

<Curing speed>
The UV curable resin compositions S1 to S17 and T1 to T17 are coated on a glass plate with an applicator to a thickness of 250 μm, and the integrated light quantity (mj / cm ² ) is gradually increased and cured under the same conditions as in Example 18. Then, the surface of the film was pressed strongly with a finger, and the integrated light amount when the fingerprint did not remain was determined.

<Leveling properties>
The leveling property in the flexographic printing method was evaluated for the ultraviolet curable resin compositions S1 to S17 and T1 to T17. The printing machine uses RK Flexiproof 100, printing conditions are printing speed 70m / min, anilox roll 180Line / inch, anilox cell capacity 20.7mL / min, engraving pattern is trihelical, one high pressure mercury lamp Curing was performed at an integrated light amount of 200 mj / cm ² , and the base material was coated cardboard printed with the UV offset ink or gravure ink, and the evaluation of the printing area was 5 × 5 cm ² .
○ ... Visually visible pinholes occurring in 5 × 5 cm ² are less than 3 locations ○ △ ··· Visually visible pinholes occurring in 5 × 5 cm ² are 3 to 6 △ ・ ・ ・ ・ ・ Visually visible pinholes generated in 5 × 5 cm ² are 6 to 10 points Δ ×... Visually visible pinholes generated in 5 × 5 cm ² are 10 15 points × · · · · · 5 × 5 cm possible pinholes visible by eye that occurred during ² 16 or more locations ○, ○ △ ranges is no practical problem.

<Abrasion resistance>
The laminates G1 to G20 and H1 to H20 (accumulated light amount 300 mj / cm ² ) are tested with a Gakushin type anti-friction tester (load 500 g, number of times 100 times, fine paper) to determine whether or not the film is removed. did.
The evaluation criteria are as follows.
○ …… Not taken.
○ △ ・ ・ ・ ・ Slightly removed.
Δ: 30-60% taken.
Δ × ... 60-80% taken.
× ・ ・ ・ ・ ・ All taken.
○ and ○ △ are ranges where there is no practical problem.

<Blocking resistance>
The laminates G1 to G20 and H1 to H20 (accumulated light amount 300 mj / cm ² ) are stacked so that the printing surface and the printing surface are in contact with each other, and a load of 10 kgf / cm ² is applied, and the environment is 40 ° C. and 80% RH. After letting it stand for 24 hours and taking it out, the state of metastasis was evaluated in five stages. The evaluation results are shown in Table 3-1 and Table 3-2.
○ ・ ・ ・ ・ ・ Transition amount 0%.
○ △ ・ ・ ・ Transition amount is less than 3%.
Δ: Transfer amount 20% or more and less than 50%.
Δ × ··· Transition amount of 50% or more and less than 80%.
× ・ ・ ・ ・ ・ Close contact with the front.
○ and ○ △ are ranges where there is no practical problem.

<Elongation rate of cured film>
The sample used in the curing rate test was peeled off from the glass, a width: 10 mm, a length: 7 cm, a test piece was prepared, and the tensile elongation was determined by a method according to JIS-K-7161. The test conditions were a distance between chucks of 3.0 cm and a tensile speed of 50 mm / min, and the elongation at break was determined.

<Self-healing of minor wounds>
The laminates G1 to G20 and H1 to H20 (accumulated light amount 300 mj / cm ² ) were lightly scratched with a nail, and the recovery state (self-healing by elasticity) was evaluated in five stages. The evaluation results are shown in Table 3-1 and Table 3-2.
○ …… Within 20 seconds until all are repaired.
○ △ ・ ・ ・ ・ Within 60 seconds until all are repaired.
Δ: 50% of the wounds are repaired in 24 hours.
Δ × ······ 30% of wounds repaired in 24 hours.
× …… Scratches are not repaired.
○ and ○ △ are ranges where there is no practical problem.

From the evaluation results, a urethane acrylate resin represented by the general formula (1), which is an ultraviolet curable resin composition that forms a coat layer for protecting a paper substrate having a printed layer on at least a part of its surface. (A), a nitrogen atom-containing acrylic monomer (B) capable of forming a homopolymer having a glass transition temperature of 80 ° C. or higher and 160 ° C. or lower, an acrylic monomer (C) having a surface tension of 20 to 35 dyn / cm, and a photopolymerization initiator By using an ultraviolet curable resin composition containing (D) and having a tensile elongation of 5% to 100% according to JIS-K-7161 based on a cured film, on a paper substrate It is an ultraviolet curable resin composition capable of forming a cured coating film having good curability at low viscosity, low bending resistance, and good bending resistance and blocking resistance. Capacity (curing rate, leveling properties during coating, abrasion resistance, blocking resistance, etc.) compatible with, and can provide a UV-curable resin composition.

In addition, in the ultraviolet curable resin composition in this invention, the self-repair function by elastic recovery was seen as an unexpected effect. If it is a mild scratch, it is self-repaired due to the nature of the coating. For example, when a box material is transported in an automobile, a truck, or the like, it is possible to automatically repair minor scratches caused by loading and rubbing the boxes against each other.

Claims (6)

An ultraviolet curable resin composition for forming a coating layer for protecting a paper substrate having a printed layer on at least a part of the surface, the urethane acrylate resin (A) represented by the following general formula (1), A nitrogen atom-containing acrylic monomer (B) capable of forming a homopolymer having a glass transition temperature of 80 ° C. or higher and 160 ° C. or lower, an acrylic monomer (C) having a surface tension of 20 to 35 dyn / cm (provided that the monomer (B) is used) And a photopolymerization initiator (D), and the cured film has a tensile elongation of 5% to 100% according to JIS-K-7161. .
General formula (1)

(Wherein R ¹ , R ² and R ³ represent an alkylene group having 10 or less carbon atoms, a divalent organic residue having a substituted or unsubstituted cyclohexylene group, a substituted or unsubstituted phenylene group, and R ⁴ Represents a caprolactone-modified (meth) acryloyl group (a-1) and / or a monovalent organic residue represented by the general formula (2).
General formula (2)

_{^{CH 2 = CR 5 -COO-R}} 6 -O-

(In the formula, R ⁵ represents a hydrogen atom or a methyl group, and R ⁶ represents an alkylene group having 10 or less carbon atoms.) The ultraviolet curable resin composition according to claim 1, wherein the caprolactone-modified (meth) acryloyl group (a-1) has a structure represented by the following general formula (3).
General formula (3)

_{^{CH 2 = CR 5 -COO-R}} 6 -O- (CO-C 5 H 10 -O) n -

(In the formula, n represents an integer of 1 to 6.) The nitrogen atom-containing acrylic monomer (B) capable of forming a homopolymer having a glass transition temperature of 80 ° C. or higher and 160 ° C. or lower is (meth) acryloylmorpholine, dimethyl (meth) acrylamide, or N, N-dimethylaminopropyl (meth) acrylamide. And at least one selected from N- (meth) acryloyloxyethyl hexahydrophthalimide, and the ultraviolet curable resin composition according to claim 1 or 2. 4. The ultraviolet curable resin composition according to claim 1, wherein the photopolymerization initiator (D) contains a benzophenone photopolymerization initiator (d-1). Weight of urethane acrylate resin (A), nitrogen atom-containing acrylic monomer (B) capable of forming a homopolymer having a glass transition temperature of 80 ° C. or higher and 160 ° C. or lower, and an acrylic monomer (C) having a surface tension of 20 to 35 dyn / cm % Ratio (A) / (B) / (C) is 60% to 40% / 55% to 35% / 10% to 1% (provided that the total of (A) to (C) is 100% by weight. The ultraviolet curable resin composition according to any one of claims 1 to 4, wherein The laminated body which has a printing layer and the coating layer formed from the ultraviolet curable resin composition in any one of Claims 1-5 on a paper base material.