JP7060071B2 - Urethane (meth) acrylate oligomer - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention has excellent appearance of a coating film after curing, no tack feeling when uncured, and good handling property, and also has excellent wear resistance, stain resistance after curing and curing / stretching, and is three-dimensional. The present invention relates to a urethane (meth) acrylate oligomer having excellent stretchability after curing to follow the deformation of processing and a curable composition using the same. The present invention also relates to a cured product and a laminate using the urethane (meth) acrylate oligomer and the curable composition.

The radical polymerization type curable composition can be cured in a short time by irradiation with active energy rays, and can provide a film having excellent chemical resistance, stain resistance, weather resistance, heat resistance, etc., and a molded product. Therefore, it is widely used in various surface processing fields and cast-molded products. Among such curable compositions, from the viewpoint of curability and work efficiency, a curable composition containing a urethane (meth) acrylate oligomer is previously cured by an active energy ray to produce a cured product, which is surface-treated. A method of performing three-dimensional processing at room temperature or under heating conditions is used. In this case, the cured product needs to have stretchability after curing in order to follow the deformation during three-dimensional processing.

Patent Document 1 describes urethane (meth) which is a reaction product of polyisocyanate, diol having an alicyclic structure, and hydroxyalkyl (meth) acrylate as having such stretchability and excellent stain resistance. A curable composition of an acrylate oligomer is disclosed.

Patent Document 2 states that both surface hardness and flexibility are good, and the active energy containing a reactant composed of a diisocyanate compound, a diol compound having 1 to 5 carbon atoms, and a monohydroxy compound having a polymerizable functional group. Linear curable oligomers are disclosed.

Japanese Unexamined Patent Publication No. 2010-22568 Japanese Unexamined Patent Publication No. 2011-042770

According to a detailed study by the present inventors, the curable composition described in Patent Document 1 has particularly insufficient wear resistance, and has a coating film appearance, scratch resistance, and stain resistance. It has been found that a curable composition having sufficiently excellent in both stretchability after curing and stain resistance after stretching has not been obtained. Further, the active energy ray-curable oligomer described in Patent Document 2 has flexibility to the extent that it exhibits hardness and good bending resistance, but has stretchability that can follow deformation during three-dimensional processing. Was found to be inadequate. That is, the problems of the present invention are excellent in the appearance of the coating film after curing, no tack feeling when uncured, and good handling property, and also in terms of wear resistance, stain resistance after curing, and stain resistance after curing / stretching. It is an object of the present invention to provide a urethane (meth) acrylate oligomer having excellent stretchability after curing in order to follow the deformation of three-dimensional processing and a curable composition using the same.

As a result of diligent studies to solve the above problems, the present inventors have obtained a urethane (meth) acrylate oligomer obtained by using a specific raw material, and a curable composition containing the same and an organic solvent. We have found that the problem can be solved and have reached the present invention. That is, the gist of the present invention lies in the following [1] to [8].

[1] Obtained by reacting at least the following compounds (A), compound (B) and compound (C), and the urethane bond amount is 5.2 × 10-3 to 10.0 × 10-3eq / g, (meth). A urethane (meth) acrylate oligomer having an acryloyl group weight of 0.8 × 10-3 to 3.0 × 10-3eq / g and a weight average molecular weight (Mw) of 1,500 to 19,000.
Compound (A): Polyisocyanate compound (B): Chain aliphatic diol compound (C) having 2 to 5 carbon atoms: Polyfunctional (meth) acrylate having a hydroxyl group

[2] The urethane (meth) acrylate oligomer according to [1], which contains at least ethylene glycol as the compound (B).

[3] [1] or [2] obtained by reacting the compound (A) with the compound (B) to obtain a urethane prepolymer and then reacting the compound (C) with the urethane prepolymer. The urethane (meth) acrylate oligomer according to.

[4] A curable composition containing the urethane (meth) acrylate oligomer according to any one of [1] to [3] and an organic solvent.

[5] The curable composition according to [4], wherein the solubility parameter of the organic solvent is 8.0 to 11.5.

[6] The curable composition according to [5], which has a solid content concentration of 5 to 90% by weight.

[7] A cured product obtained by irradiating the curable composition according to [5] or [6] with active energy rays.

[8] A laminate obtained by applying the curable composition according to any one of [4] to [6] onto a substrate and irradiating it with active energy rays to cure it.

According to the present invention, the appearance of the coating film after curing is excellent, there is no tack feeling when uncured, the handling property is good, and the abrasion resistance, the stain resistance after curing and after curing / stretching are excellent. Provided are a urethane (meth) acrylate oligomer having excellent stretchability after curing for following the deformation of three-dimensional processing, and a curable composition using the same. Further, according to the present invention, a cured product or a laminate using the urethane (meth) acrylate oligomer and the curable composition is provided.

Hereinafter, embodiments of the present invention will be described in detail, but the following description is typical examples of embodiments of the present invention, and the present invention is not limited to these contents. In the present invention, "(meth) acrylate" is a general term for acrylate and methacrylate, and means one or both of acrylate and methacrylate. Regarding "(meth) acryloyl" and "(meth) acrylic" Is the same. Further, in the present invention, "-" is used in the sense that the numerical values described before and after it are included as the lower limit value and the upper limit value.

[Urethane (meth) acrylate oligomer]
The urethane (meth) acrylate oligomer of the present invention is obtained by reacting at least the following compounds (A), compound (B) and compound (C), and has a urethane bond amount of 5.2 × 10-3 to 10.0 ×. 10-3eq / g, (meth) acryloyl group weight of 0.8 × 10-3 to 3.0 × 10-3eq / g, and weight average molecular weight (Mw) of 1,500 to 19,000. Is.
Compound (A): Polyisocyanate compound (B): Chain aliphatic diol compound (C) having 2 to 5 carbon atoms: Polyfunctional (meth) acrylate having a hydroxyl group

The urethane (meth) acrylate oligomer of the present invention and the curable composition of the present invention described later are excellent in handleability without the appearance of a coating film after curing and the feeling of tackiness when uncured, and also have abrasion resistance, after curing and It has excellent stain resistance after curing and stretching, and excellent stretchability after curing that can follow deformation during three-dimensional processing. In particular, the handleability is remarkably superior to the curable composition described in Patent Documents 1 and 2, and the stretchability capable of following the deformation during three-dimensional processing is described in Patent Document 2. It is remarkably superior to the curable composition.

The reason why the curable composition of the present invention exerts the above-mentioned excellent effects is not clear, but the handleability is considered to be due to the following reasons. That is, the urethane (meth) acrylate oligomer of the present invention is intramolecular by using a chain aliphatic diol having a short chain length (chain aliphatic diol having 2 to 5 carbon atoms) as the compound (B) used as a raw material. It is considered that this is because the distance between urethane bonds is shortened, strong hydrogen bonds derived from urethane bonds are formed between molecules, and the hardness and rigidity of the uncured coating film are obtained. Although similar hydrogen bonds are formed in the urethane (meth) acrylate oligomers described in Patent Documents 1 and 2, it is presumed that the obtained hardness and rigidity are insufficient due to the low urethane bond amount. To.

Further, regarding the stretchability after curing, hydrogen bonds are relaxed at high temperatures, and it is considered that the stretchability (elongation of the cured product) is dominated by the crosslink density between the (meth) acryloyl groups. Since the urethane (meth) acrylate oligomer described in Patent Document 2 has a higher amount of (meth) acryloyl group than the urethane (meth) acrylate oligomer of the present invention, it is presumed that the stretchability is insufficient.

Further, regarding the stain resistance after curing, since the component (C) has a plurality of (meth) acryloyl groups, the crosslinkability between the molecules when the urethane (meth) acrylate oligomer is cured is enhanced, and the molecule. This is thought to be due to the stronger intermolecular network. In particular, regarding the stain resistance after curing and stretching, the urethane bond amount relaxed by heating during the stretching step due to the high urethane bond amount of the urethane (meth) acrylate oligomer of the present invention is relaxed during heat removal. It is presumed that this is due to the reconstruction into a regular intermolecular network.

[Compound (A)]
The compound (A) used in the present invention is a polyisocyanate. Polyisocyanate is a compound having a total of two or more isocyanate groups and / or substituents containing an isocyanate group in one molecule. As the compound (A), one kind may be used, or two or more kinds may be used. In addition, in this invention, an isocyanate group and a substituent containing an isocyanate group are generically referred to as "
It may be referred to as "isocyanate group". Further, in compound (A), the isocyanate groups may be the same or different.

Examples of the substituent containing an isocyanate group include an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 1 to 5 carbon atoms, and an alkoxyl group having 1 to 5 carbon atoms, which contain one or more isocyanate groups. Among these, an alkyl group having 1 to 5 carbon atoms is preferable, and an alkyl group having 1 to 3 carbon atoms is particularly preferable.

The type of polyisocyanate is not particularly limited, and examples thereof include chain aliphatic polyisocyanates, aromatic polyisocyanates, alicyclic polyisocyanates, and even if one of these is used, two or more of them can be combined. May be used. Among these, the component (A) preferably contains an alicyclic polyisocyanate from the viewpoint of increasing the weather resistance and hardness of the obtained cured product.

The chain aliphatic polyisocyanate is a compound having a chain aliphatic structure and two or more isocyanate groups bonded to the chain aliphatic structure. The chain aliphatic polyisocyanate is preferable from the viewpoint of enhancing the weather resistance of the cured film obtained by curing the curable composition and imparting stretchability. The chain aliphatic structure in the chain aliphatic polyisocyanate is not particularly limited, but is preferably a linear or branched alkylene group having 1 to 6 carbon atoms. Examples of such chain aliphatic polyisocyanates include aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and dimerate diisocyanate, and aliphatic triisocyanates such as tris (isocyanate hexyl) isocyanurate. Isocyanate can be mentioned. These may be used alone or in combination of two or more.

Aromatic polyisocyanates are compounds having an aromatic structure and two or more isocyanate groups attached to it. The aromatic structure of the aromatic polyisocyanate is not particularly limited, but is preferably an aromatic structure having 6 to 13 carbon atoms. Examples of such aromatic polyisocyanates include aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, m-phenylenedi isocyanate, and naphthalene diisocyanate. Aromatic polyisocyanates are preferable from the viewpoint of increasing the mechanical strength of the cured film obtained by curing the curable composition, and examples of such aromatic polyisocyanates include tolylene diisocyanate and diphenylmethane diisocyanate. These may be used alone or in combination of two or more.

The alicyclic polyisocyanate is a compound having an alicyclic structure and two or more isocyanate groups. The alicyclic structure of the compound (A) is not particularly limited, but is preferably 5 to 15 carbon atoms, and more preferably 6 or more carbon atoms. Further, the number of carbon atoms is more preferably 14 or less, and particularly preferably 13 or less. Further, the alicyclic structure is preferably a cycloalkylene group. Examples of the polyisocyanate having an alicyclic structure include diisocyanate having an alicyclic structure such as bis (isocyanatemethyl) cyclohexane, cyclohexanediisocyanate, bis (isocyanatecyclohexyl) methane, and isophorone diisocyanate, and tris (isocyanate isophorone) isocyanurate. Examples thereof include triisocyanates having an alicyclic structure of. Among these, it is preferable to contain isophorone diisocyanate.

[Compound (B)]
The compound (B) used in the present invention is a chain aliphatic diol having 2 to 5 carbon atoms. The chain structure in compound (B) may be linear or branched.

Examples of the compound (B) include ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 1,2-butanediol, and 1,3-butanediol. Examples thereof include 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, and 1,5-pentanediol. Among these, if it contains at least one of ethylene glycol and 1,4-butanediol, it is possible to obtain a curable composition having excellent stain resistance after curing, abrasion resistance, and handleability when uncured. Of these, ethylene glycol is particularly preferable.

In the present invention, the compound (B) is used in an amount of 40% by weight or more based on the total diol component used as a raw material of the urethane (meth) acrylate oligomer, that is, stain resistance after curing, abrasion resistance, and uncured. It is preferable from the viewpoint of improving the handleability of the material. Further, in order to further enhance this effect, the compound (B) is more preferably 60% by weight or more, further preferably 80% by weight or more, particularly preferably 90% by weight or more, while the upper limit. Is usually 100% by weight.

[Compound (C)]
The polyfunctional (meth) acrylate having a hydroxyl group of the compound (C) used in the present invention is a compound having one or more hydroxyl groups, two or more (meth) acryloyl groups and a hydrocarbon group. The polyfunctional (meth) acrylate having a hydroxyl group forms a good crosslinked structure due to the involvement of a plurality of (meth) acryloyl groups in the curing reaction when obtaining a cured film, and has physical properties such as stain resistance and wear resistance. Can be made good.

Examples of the compound (C) include bisphenol A diglycidyl ether diacrylate, 1,4-cyclohexanedimethanol diglycidyl ether diacrylate, ethylene glycol diglycidyl ether diacrylate, and 1,4-butanediol diglycidyl ether diacrylate. Examples thereof include 1,6-hexanediol diglycidyl ether diacrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, and dipentaerythritol penta (meth) acrylate.

Among these, an alkylene group having 2 to 4 carbon atoms between a (meth) acryloyl group such as pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, and dipentaerythritol penta (meth) acrylate and a hydroxyl group. Hydroxyalkyl poly (meth) acrylates having the above are particularly preferable from the viewpoint of the mechanical strength of the obtained cured film.

The molecular weight of compound (C) is preferably 100 or more, more preferably 200 or more. On the other hand, the molecular weight of the compound (C) is preferably 800 or less, more preferably 500 or less, from the viewpoint of the mechanical strength of the obtained cured film. When compound (C) is the addition reactant or polymer, the molecular weight means a number average molecular weight measured by gel permeation chromatography (GPC measurement).

[Other raw material compounds]
In the raw material compound of the urethane (meth) acrylate oligomer of the present invention, other raw material compounds other than the compound (A), the compound (B) and the compound (C) may be used as long as the effects of the present invention are not significantly impaired. good. Examples of such other raw material compounds include chain aliphatic diols having 6 to 16 carbon atoms, diols having an alicyclic structure, polyalkylene glycols, and high molecular weight polyols other than these (hereinafter, “other high molecular weight compounds”). "Polyol"), hydroxyalkyl mono (meth) acrylate, chain extender and the like.

Examples of the chain aliphatic diol having 6 to 16 carbon atoms include 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, and 1,9. -Nonanediol, 1-10decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,14-tetracandiol, 1,16-hexadecanediol, 2,2,4-trimethyl-1,3 -Pentanediol, 2-methyl-1,8-octanediol and the like can be mentioned. These may be used alone or in combination of two or more.

Examples of the diol having an alicyclic structure include 1,4-cyclohexanedimethanol, hydrogenated bisphenol A and the like. These may be used alone or in combination of two or more.

Examples of the polyalkylene glycol include polyethylene glycol, polypropylene glycol, polytrimethylene glycol, polytetramethylene glycol and the like. These may be used alone or in combination of two or more.

Examples of other high molecular weight polyols include polyether diols, polyester diols, polyether ester diols, polyolefin polyols, silicon polyols and the like. These may be used alone or in combination of two or more.

Examples of the hydroxyalkyl mono (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and cyclohexanedi. Methanol mono (meth) acrylate, addition reaction product of 2-hydroxyethyl (meth) acrylate and caprolactone, addition reaction product of 4-hydroxybutyl (meth) acrylate and caprolactone, addition of glycidyl ether and (meth) acrylic acid. Examples thereof include a reactant, a mono (meth) acrylate of glycol, and the like. Among these, the number of carbon atoms between the (meth) acryloyl group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and the hydroxyl group is 2 to 4 Hydroxyalkyl mono (meth) acrylates having the above alkylene group are preferable from the viewpoint of the mechanical strength of the obtained cured film. These may be used alone or in combination of two or more.

A chain extender is a compound having two or more active hydrogens that react with an isocyanate group. Examples of the chain extender include low molecular weight diamine compounds having a number average molecular weight of less than 500, and examples thereof include aromatics such as 2,4- or 2,6-tolylene diamine, xylylene diamine, and 4,4'-diphenylmethanediamine. Group diamines; ethylene diamine, 1,2-propylene diamine, 1,6-hexanediamine, 2,2-dimethyl-1,3-propanediamine, 2-methyl-1,5-pentanediamine, 2,2,4-or An aliphatic diamine such as 2,4,4-trimethylhexanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine; And 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 4,4'-dicyclohexylmethanediamine, isopropyridenecyclohexyl-4,4'-diamine, 1,4-diaminocyclohexane, 1,3 -Alicyclic diamines such as bisaminomethylcyclohexane and tricyclodecanediamine can be mentioned. These may be used alone or in combination of two or more.

[Physical characteristics of urethane (meth) acrylate oligomer]
The urethane bond amount of the urethane (meth) acrylate oligomer is 5.2 × 10-3 to 10.0 × 10-3 eq / g. When the urethane bond amount is 5.2 × 10-3 or more, the stain resistance of the cured film and the handling property of the uncured film are improved, and when it is 10.0 × 10-3 eq / g or less, the solution stability is improved. Handleability is improved. Further, from the viewpoint of improving these effects, the urethane bond amount of the urethane (meth) acrylate oligomer is preferably 5.3 × 10-3 eq / g or more, 5.5 × 10-3 eq. It is more preferably / g or more, further preferably 5.8 × 10-3 eq / g or more, while it is preferably 9.0 × 10-3 eq / g or less, and 8.0 × 10 or less. It is more preferably -3 eq / g or less. The urethane bond amount can be controlled by adjusting the raw material composition of the urethane (meth) acrylate oligomer.

Further, in the present invention, the above urethane bond amount is calculated as follows. The urethane (meth) acrylate oligomer of the present invention is a polyisocyanate of compound (A), a chain aliphatic diol having 2 to 5 carbon atoms of compound (B), and a polyfunctional (meth) having a hydroxyl group of compound (C). The acrylate is used as a raw material, and the structural unit of the obtained urethane (meth) acrylate oligomer can be regarded as the one in which the raw material composition used is maintained as it is. From this, the total equivalent number of urethane bonds (total value of isocyanate groups (total value obtained by multiplying the number of moles of polyisocyanate by the number of functional groups of isocyanate groups) and all functional groups that react with isocyanate groups such as hydroxyl groups and amino groups Divide the lower value of the total equivalent number by the total amount of the constituent components of the urethane (meth) acrylate oligomer (the total amount of each raw material component excluding the excessively added component amount (not the charged amount)). Is calculated.

The (meth) acryloyl group amount of the urethane (meth) acrylate oligomer is 0.8 × 10-3 to 3.0 × 10-3 eq / g. When the amount of (meth) acryloyl group is 0.8 × 10-3 eq / g or more, stain resistance and wear resistance after curing are improved, and when it is 3.0 × 10-3 eq / g or less, three-dimensional processing is performed. The stretchability after curing that can follow the deformation with time is improved. Further, from the viewpoint of improving these effects, the amount of (meth) acryloyl group of the urethane (meth) acrylate oligomer is preferably 0.9 × 10-3 eq / g or more, preferably 1.0 ×. It is more preferably 10-3 eq / g or more, while it is preferably 2.7 × 10-3 eq / g or less, and more preferably 2.5 × 10-3 eq / g or less. The amount of the (meth) acryloyl group described above can be controlled by adjusting the raw material composition of the urethane (meth) acrylate oligomer.

Further, in the present invention, the above-mentioned (meth) acryloyl group amount is calculated as follows. The urethane (meth) acrylate oligomer of the present invention is a polyisocyanate of compound (A), a chain aliphatic diol having 2 to 5 carbon atoms of compound (B), and a polyfunctional (meth) having a hydroxyl group of compound (C). The acrylate is used as a raw material, and the structural unit of the obtained urethane (meth) acrylate oligomer can be regarded as the one in which the raw material composition used is maintained as it is. From this, the number of (meth) acryloyl groups (the total value obtained by multiplying the number of moles of the polyfunctional (meth) acrylate having a hydroxyl group excluding the amount of the excessively added component by the number of (meth) acryloyl groups) is urethane. It is calculated by dividing by the total amount of the constituent components of the (meth) acrylate oligomer (the total amount of each raw material component excluding the excessively added component amount (not the charged amount)).

The weight average molecular weight (Mw) of the urethane (meth) acrylate oligomer is preferably 1,500 or more, more preferably 3,000 or more, and more preferably 19,000 or less, 8. It is more preferably 000 or less. When the weight average molecular weight of the urethane (meth) acrylate oligomer is at least the above lower limit value, the three-dimensional processability of the obtained cured film tends to be good. When the weight average molecular weight of the urethane (meth) acrylate oligomer is not more than the above upper limit value, the stain resistance of the cured film obtained from the curable composition tends to be good. The weight average molecular weight of the urethane (meth) acrylate oligomer is related to the three-dimensional processing suitability and stain resistance of the cured film obtained by using it, and the distance between the cross-linking points in the network structure is related. The smaller the weight average molecular weight, the more the cross-linking points. The distance between them is short, and the larger the weight average molecular weight, the longer the distance between the cross-linking points tends to be. The reason why the weight average molecular weight affects the 3D processing suitability and stain resistance is that the longer the distance between the cross-linking points, the more flexible and stretchable the structure becomes, and the better the 3D processing suitability, while the shorter the distance, the stronger the network structure. It is presumed that the structure will be more stable and the scratch resistance, stain resistance, and abrasion resistance will be better. The weight average molecular weight of the urethane (meth) acrylate oligomer can be determined by gel permeation chromatography measurement (GPC measurement), and a more detailed measurement method will be shown in the examples below.

[Manufacturing method of urethane (meth) acrylate oligomer]
The urethane (meth) acrylate oligomer of the present invention can be produced by subjecting the compound (A) to an addition reaction between the compound (B) and the compound (C). In addition, the charging ratio of each raw material compound at that time is usually substantially the same as or the same as the composition of the target urethane (meth) acrylate oligomer.

These addition reactions can be carried out by using any of the known methods for producing urethane (meth) acrylate oligomers. Examples of such a method include the following methods (1) to (3).
(1) The compound (A) and the compound (B) are reacted under conditions such that the isocyanate group becomes excessive to obtain a urethane prepolymer having an isocyanate terminal, and then the urethane prepolymer having the isocyanate terminal is obtained. A method for reacting the compound (C) with the compound (C). (2) A method in which all raw material compounds are simultaneously added and reacted at the same time.
(3) Obtained after reacting the compound (A) with the compound (C) first to synthesize a urethane (meth) acrylate prepolymer having a (meth) acryloyl group and an isocyanate group in the molecule at the same time. A method for reacting compound (B) with a prepolymer.

Of these, according to the method (1), the urethane prepolymer is obtained by subjecting compound (A) and compound (B) to a urethanization reaction. The target urethane (meth) acrylate oligomer has a structure formed by a urethanization reaction between a urethane prepolymer having an isocyanate group at the terminal and compound (C). According to the method (1), the molecular weight can be easily controlled, and (meth) acryloyl groups can be introduced at both ends, so that a cured film can be easily obtained, which is preferable.

The amount of total isocyanate groups in the urethane (meth) acrylate oligomer and the amount of total functional groups that react with isocyanate groups such as hydroxyl and amino groups are usually theoretically the molars. Therefore, the amount of the compound (A), the compound (B) and the compound (C) and other raw material compounds used as raw materials is the amount of the total isocyanate groups in the urethane (meth) acrylate oligomer and the total functional groups reacting with the total isocyanate groups. The amount is an equivalent amount or an amount such that the equivalent% of the total functional group with respect to the isocyanate group is 50 to 200 equivalent%.

When producing the urethane (meth) acrylate oligomer, the amount of the compound (C) to be used is 3 mol with respect to the total amount of the compound containing the functional group reacting with the isocyanate group in the compound (C) and other raw materials. % Or more is preferable, 5 mol% or more is more preferable, while 70 mol% or less is preferable, 50 mol% or less is more preferable, and 30 mol% or less is particularly preferable. With this ratio, the molecular weight of the obtained urethane (meth) acrylate oligomer can be controlled. When the proportion of the compound (C) is large, the molecular weight of the urethane (meth) acrylate oligomer tends to be small, and when the proportion is small, the molecular weight tends to be large.

Further, when a chain extender is used, the compound (B), the diol component other than the compound (B), and all the polyols (compounds having two or more alcoholic hydroxyl groups) of the other polyol components and the chain extender are used. The total amount of the polyol used is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, based on the total amount of the compound used. It is particularly preferable that the content is 95 mol% or more. When the total amount of the polyol is not more than the lower limit, the liquid stability tends to be improved.

The ratio of raw materials used is a guideline for producing urethane (meth) acrylate oligomers. Actually, it is preferable to finely adjust the raw material mixing ratio within the above range according to the desired physical properties.

In the production of urethane (meth) acrylate oligomers, an organic solvent can be used for the purpose of adjusting the viscosity. As the organic solvent, one kind may be used alone, or two or more kinds may be mixed and used. As the organic solvent, any known organic solvent can be used as long as the effect of the present invention can be obtained. Preferred organic solvents include toluene, xylene, ethyl acetate, butyl acetate, cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, N-methylpyrrolidone, dimethylformamide and the like. The organic solvent can usually be used in an amount of 300 parts by weight or less with respect to 100 parts by weight of the solid content in the reaction system.

In the production of the urethane (meth) acrylate oligomer, the total content of the urethane (meth) acrylate oligomer and its raw material compound to be produced is preferably 20% by weight or more, preferably 40% by weight or more, based on the total amount of the reaction system. It is more preferable to have. The upper limit of this total content is usually 100% by weight. When the total content of the urethane (meth) acrylate oligomer and its raw material compound is at least the above lower limit, the reaction rate tends to be high and the production efficiency tends to be improved, which is preferable.

A catalyst can be used in the production of the urethane (meth) acrylate oligomer. The catalyst can be selected from the range in which the effects of the present invention can be obtained, and for example, tin-based catalysts such as dibutyltin laurate, dibutyltin dioctate, dioctyltin dilaurate, and dioctyltin dioctate; bismuth tris (2- Examples thereof include bismuth-based catalysts such as ethylhexanate 9. As the catalyst, one type may be used alone, or two or more types may be mixed and used. Among these, the catalyst is dioctyltin dilaurate. Bismuth tris (2-ethylhexanate) is preferable from the viewpoint of environmental adaptability, catalytic activity, storage stability, etc. The upper limit of the amount of the catalyst used is usually 2 with respect to the total content of the raw material compound. It is used at 000 ppm or less, preferably 1,000 ppm or less, and the lower limit is usually 10 ppm or more, preferably 30 ppm or more. In the case of producing by the method of the above (1), the compound (A) and the compound (A) are particularly used. It is preferable to use the above catalyst in both the reaction of reacting with B) to obtain a urethane prepolymer and the reaction of adding the compound (C) to the urethane prepolymer.

When a compound containing a (meth) acryloyl group such as compound (C) is used in the reaction system during the production of the urethane (meth) acrylate oligomer, it is preferable to use a polymerization inhibitor in combination. Examples of such a polymerization inhibitor include phenols such as hydroquinone, methylhydroquinone, hydroquinone monoethyl ether and dibutylhydroxytoluene, amines such as phenothiazine and diphenylamine, copper salts such as copper dibutyldithiocarbamate, and manganese acetate. Examples thereof include manganese salts, nitro compounds and nitroso compounds. As the polymerization inhibitor, one type may be used alone, or two or more types may be mixed and used. Of these, phenols are preferable as the polymerization inhibitor. The upper limit of the amount of the polymerization inhibitor used is usually 3,000 ppm or less, preferably 1,000 pp, with respect to the total content of the raw material compound.
It is m or less, particularly preferably 500 ppm or less, while the lower limit is usually 50 ppm or more, preferably 100 ppm or more.

In the production of the urethane (meth) acrylate oligomer, the reaction temperature is preferably 20 ° C. or higher, preferably 40 ° C. or higher, and more preferably 60 ° C. or higher. When the reaction temperature is at least the above lower limit value, the reaction rate tends to be high and the production efficiency tends to be improved, which is preferable. The reaction temperature is preferably 120 ° C. or lower, more preferably 100 ° C. or lower. When the reaction temperature is not more than the above upper limit value, side reactions such as an alohanate reaction are less likely to occur, which is preferable. When the reaction system contains an organic solvent, the reaction temperature is preferably lower than the boiling point of the organic solvent, and when a compound having a (meth) acryloyl group such as compound (C) is contained (meth). ) The temperature is preferably 70 ° C. or lower from the viewpoint of preventing the acryloyl group from reacting excessively. The reaction time is usually 5 to 20 hours.

[Cursable composition]
The curable composition of the present invention contains at least the above-mentioned urethane (meth) acrylate oligomer of the present invention and an organic solvent.

<Organic solvent>
The curable composition of the present invention contains an organic solvent. By using an organic solvent, the urethane (meth) acrylate oligomer is satisfactorily dissolved, and as will be described later, the viscosity for forming a coating film when the urethane (meth) acrylate oligomer is irradiated with active energy rays and cured. Can be adjusted to obtain a uniform cured film.

As the organic solvent, any known organic solvent can be used as long as the effect of the present invention can be obtained. An organic solvent having a solubility parameter (hereinafter referred to as “SP value”) of 8.0 to 11.5 is preferable. When the SP value is 8 or more, it is preferable from the viewpoint of solubility of the urethane (meth) acrylate oligomer, while when it is 11.5 or less, it is preferable from the viewpoint of the transparency of the solution. Examples of the organic solvent in the above range include toluene (SP value: 9.1), xylene (SP value: 9.1), ethyl acetate (SP value: 8.7), butyl acetate (SP value: 8.7). ), Cyclohexanone (SP value: 9.8), Methylethylketone (SP value: 9.0), Methylisobutylketone (SP value: 8.7), N-methylpyrrolidone (SP value: 11.2) and the like. Be done. In the present invention, the SP value represents the solubility parameter, and the value is calculated by the method proposed by Fedors et al. Specifically, it is a value obtained by referring to "POLYMER ENGINEERING AND SCIENCE, FEBRUARY, 1974, Vol. 14, No. 2, ROBERT F. FEDORS. (Pages 147 to 154)". The SP value is a physical property value determined by the content of the hydrophobic group and the hydrophilic group of the molecule, and when a mixed solvent is used, it means a value as a mixture.

The organic solvent can usually be used in a curable composition having a solid content concentration of 5 to 90% by weight, and the solid content concentration is preferably 10% by weight or more, more preferably 15% by weight or more. On the other hand, it is preferably 80% by weight or less, more preferably 70 parts by weight or less, and further preferably 60% by weight or less. The "solid content" here means not only the urethane acrylate (meth) acrylate oligomer but also all the components excluding the solvent, and not only the solid state but also the semi-solid and viscous liquid substances. It shall include.

<Other ingredients>
The curable composition of the present invention may be referred to as a component other than the urethane (meth) acrylate oligomer and the organic solvent (in the present invention, "other components", as long as the effect of the present invention is not significantly impaired. Yes.) May be contained. Examples of other components include active energy ray-reactive monomers, active energy ray-curable oligomers (excluding the urethane (meth) acrylate oligomers of the present invention), polymerization initiators, photosensitizers, epoxy compounds and other components. Additives and the like can be mentioned.

In the curable composition of the present invention, the content of the urethane (meth) acrylate oligomer is 40% by weight or more based on the total amount of all the components excluding the solvent in the curable composition such as the active energy ray-reactive component. It is preferably present, and more preferably 60% by weight or more. When the content of the urethane (meth) acrylate oligomer is at least the above lower limit value, the curability is good, and the mechanical strength of the cured film does not become too high, and the three-dimensional processing suitability tends to be improved. Therefore, it is preferable. The upper limit of the content of the urethane (meth) acrylate oligomer is 100% by weight.

Further, in the curable composition of the present invention, the total content of the active energy ray-reactive component containing the urethane (meth) acrylate oligomer is excellent in the curing rate and surface curability of the composition, and no tack remains. From this aspect, it is preferably 60% by weight or more, more preferably 80% by weight or more, further preferably 90% by weight or more, and 95% by weight or more, based on the total amount of the composition. Is particularly preferred. The upper limit of this content is 100% by weight.

As the active energy ray-reactive monomer, any known active energy ray-reactive monomer can be used as long as the effect of the present invention can be obtained. These active energy ray-reactive monomers are used for the purpose of adjusting the physical properties such as the hydrophobicity of the urethane (meth) acrylate oligomer and the hardness and elongation of the cured film when the obtained composition is used as the cured film. To. The active energy ray-reactive monomer may be used alone or in combination of two or more.

Examples of such active energy ray-reactive monomers include vinyl ethers, (meth) acrylamides, and (meth) acrylates, and specific examples thereof include styrene, α-methylstyrene, and α-chlorostyrene. , Vinyl toluene, aromatic vinyl monomers such as divinylbenzene; vinyl acetate, butyric acid vinyl, N-vinylformamide, N-vinylacetamide, N-vinyl-2-pyrrolidone, N-vinylcaprolactam, divinyl adipate, etc. Ester monomers; Vinyl ethers such as ethyl vinyl ether and phenyl vinyl ether; Allyl compounds such as diallyl phthalate, trimethylolpropane diallyl ether and allyl glycidyl ether; (meth) acrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylic Amid, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, Nt-butyl (meth) acrylamide, (meth) acrylic morpholine, methylenebis (meth) acrylamide, etc. (Meta) acrylamides; (meth) acrylic acid, methyl (meth) acrylic acid, ethyl (meth) acrylic acid, propyl (meth) acrylic acid, (meth) acrylic acid-n-butyl, (meth) acrylic acid- i-butyl, (meth) acrylic acid-t-butyl, (meth) acrylate hexyl, (meth) acrylic acid-2-ethylhexyl, (meth) acrylate lauryl, (meth) acrylic acid stearyl, (meth) acrylic acid Tetrahydroflufuryl, morpholyl (meth) acrylate, -2-hydroxyethyl (meth) acrylate, -2-hydroxypropyl (meth) acrylate, -4-hydroxybutyl (meth) acrylate, glycidyl acrylate (meth) , (Meta) dimethylaminoethyl acrylate, (meth) diethylaminoethyl acrylate, (meth) benzyl acrylate, (meth) cyclohexyl acrylate, (meth) phenoxyethyl acrylate, (meth) tricyclodecane acrylate, ( Dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, allyl (meth) acrylate, -2-ethoxyethyl (meth) acrylate, (meth) Monofunctional (meth) ac of isobornyl acrylate, phenyl (meth) acrylate, etc. Relate; and di (meth) acrylate ethylene glycol, di (meth) acrylate diethylene glycol, di (meth) acrylate triethylene glycol, di (meth) acrylate tetraethylene glycol, di (meth) acrylate polyethylene glycol ( n = 5-14), propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, di (meth) Polypropylene glycol acrylate (n = 5-14), di (meth) acrylate-1,3-butylene glycol, di (meth) acrylate-1,4-butanediol, di (meth) acrylate polybutylene glycol (meth) n = 3 to 16), di (meth) acrylic acid poly (1-methylbutylene glycol) (n = 5 to 20), di (meth) acrylic acid-1,6-hexanediol, di (meth) acrylic acid- 1,9-Nonandiol, Neopentyl glycol di (meth) acrylate, Neopentyl glycol hydroxypivalate Di (meth) acrylic acid ester, Dicyclopentanediol di (meth) acrylate, Tricyclo di (meth) acrylate Decane, bisphenol A diglycidyl ether diacrylate, 1,4-cyclohexanedimethanol diglycidyl ether diacrylate, ethylene glycol diglycidyl ether diacrylate, 1,4-butanediol diglycidyl ether diacrylate, 1,6-hexanediol di Glycidyl ether diacrylate, trimethylol propantri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropanetetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipenta Elythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropanetrioxyethyl (meth) acrylate, trimethylolpropanetrioxypropyl (meth) acrylate, trimethylolpropanepolyoxyethyl (meth) acrylate, tri. Methylolpropanpolyoxypropyl (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, tris (2-hydroxyethyl) a Socianurate di (meth) acrylate, ethylene oxide-added bisphenol A di (meth) acrylate, ethylene oxide-added bisphenol F di (meth) acrylate, propylene oxide-added bisphenol A di (meth) acrylate, propylene oxide-added bisphenol F di (meth) acrylate, Examples thereof include polyfunctional (meth) acrylates such as tricyclodecanedimethanol di (meth) acrylate, bisphenol A epoxy di (meth) acrylate, and bisphenol F epoxy di (meth) acrylate.

Among these, particularly in applications where the composition of the present invention is required to have coatability, (meth) acryloylmorpholin, (meth) tetrahydrofurfuryl acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate. , (Meth) trimethylcyclohexyl acrylate, (meth) phenoxyethyl acrylate, (meth) tricyclodecane acrylate, (meth) dicyclopentenyl acrylate, (meth) isobornyl acrylate, (meth) acrylamide, and the like. Monofunctional (meth) acrylates having a ring structure inside are preferable, while di (meth) acrylic acid-1,4-butanediol and di (meth) are used in applications where the mechanical strength of the obtained cured film is required. ) Acrylic acid-1,6-hexanediol, di (meth) acrylic acid-1,9-nonanediol, di (meth) acrylic acid neopentylglycol, di (meth) acrylic acid tricyclodecane, 1,4-cyclohexane Dimethanol diglycidyl ether diacrylate, ethylene glycol diglycidyl ether diacrylate, 1,4-butanediol diglycidyl ether diacrylate, 1,6-hexanediol diglycidyl ether diacrylate, trimethyl propanthyl (meth) acrylate, penta Polyfunctional (meth) acrylates such as erythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate Preferably, in applications where the stretchability of the obtained cured film is required, di (meth) polyethylene glycol di (meth) acrylate (n = 5 to 14), di (meth) polypropylene glycol di (meth) acrylate (n = 5 to 14), di (meth). ) Polyether (meth) acrylates such as polybutylene glycol acrylate (n = 3 to 16) and poly (meth) acrylate (1-methylbutylene glycol) (n = 5 to 20) are preferable.

In the curable composition of the present invention, the content of the active energy ray-reactive monomer is relative to the total amount of the composition from the viewpoint of adjusting the viscosity of the composition and adjusting the physical properties such as hardness and elongation of the obtained cured film. It is preferably 50% by weight or less, more preferably 30% by weight or less, further preferably 20% by weight or less, and further preferably 10% by weight or less.

The active energy ray-curable oligomer may be used alone or in combination of two or more. Examples of the active energy ray-curable oligomer include epoxy (meth) acrylate-based oligomers, acrylic (meth) acrylate-based oligomers, polyester (meth) acrylate-based oligomers, polycarbonate (meth) acrylate-based oligomers, and polybutadiene (meth) acrylate-based oligomers. , Polyether (meth) acrylates (excluding those described in the active energy ray reactive monomers). In the curable composition of the present invention, the content of the active energy ray-reactive oligomer is 50% by weight or less with respect to the total amount of the composition from the viewpoint of adjusting physical properties such as hardness and elongation of the obtained cured film. It is preferably 30% by weight or less, more preferably 20% by weight or less, and particularly preferably 10% by weight or less.

The polymerization initiator is mainly used for the purpose of improving the initiation efficiency of a polymerization reaction that proceeds by irradiation with active energy rays such as ultraviolet rays and electron beams. As the polymerization initiator, a photoradical polymerization initiator which is a compound having a property of generating radicals by light is generally used, and any known photoradical polymerization initiator can be used as long as the effect of the present invention can be obtained. Is. As the polymerization initiator, one type may be used alone, or two or more types may be mixed and used. Further, a photoradical polymerization initiator and a photosensitizer may be used in combination.

Examples of the photoradical polymerization initiator include benzophenone, 2,4,6-trimethylbenzophenone, 4,4-bis (diethylamino) benzophenone, 4-phenylbenzophenone, methyl orthobenzoylbenzoate, thioxanthone, diethylthioxanthone, isopropylthioxanthone, and chloro. Thioxanthone, 2-ethylanthraquinone, t-butylanthraquinone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethylketal, 1-hydroxycyclohexylphenylketone, benzoinmethylether, benzoinethyl Ether, benzoin isopropyl ether, benzoin isobutyl ether, methylbenzoylformate, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one, 2,6-dimethylbenzoyldiphenylphosphine oxide, 2 , 4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, and 2- Hydroxy-1- [4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl] -2-methyl-propane-1-one and the like can be mentioned.

Among these, benzophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenylketone, 2,4,6 are available because the curing rate is high and the crosslink density can be sufficiently increased. -Trimethylbenzoyldiphenylphosphine oxide and 2-hydroxy-1- [4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl] --2-methyl-propane-1-one Preferably, 1-hydroxycyclohexylphenylketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and 2-hydroxy-1- [4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl. ] -2-Methyl-Propane-1-one is more preferred.

When the curable composition contains a compound having a cationically polymerizable group such as an epoxy group together with a radically polymerizable group, the curing initiator includes a photocationic polymerization initiator together with the above-mentioned photoradical polymerization initiator. It may be. As the photocationic polymerization initiator, any known photocationic polymerization initiator can be used as long as the effect of the present invention is not significantly impaired.

The content of these polymerization initiators in the curable composition of the present invention is preferably 10 parts by weight or less, preferably 5 parts by weight or less, based on 100 parts by weight of the total of the active energy ray-reactive components. It is more preferable to have. When the content of the photopolymerization initiator is not more than the above upper limit value, the mechanical strength is less likely to be lowered by the initiator decomposition product, which is preferable.

The photosensitizer can be used for the same purpose as the polymerization initiator. As the photosensitizer, one type may be used alone, or two or more types may be mixed and used. As the photosensitizer, any known photosensitizer can be used as long as the effects of the present invention can be obtained. Examples of such a photosensitizer include ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, and amyl 4-dimethylaminobenzoate. And 4-dimethylaminoacetophenone and the like.

In the curable composition of the present invention, the content of the photosensitizer is preferably 10 parts by weight or less, preferably 5 parts by weight or less, based on 100 parts by weight of the total of the active energy ray-reactive components. Is more preferable. When the content of the photosensitizer is not more than the above upper limit value, the mechanical strength is less likely to decrease due to the decrease in the crosslink density, which is preferable.

The additive is arbitrary as long as the effect of the present invention can be obtained, and various materials added to the composition used for the same purpose can be used as the additive. As the additive, one type may be used alone, or two or more types may be mixed and used. Examples of such additives include glass fibers, glass beads, silica, alumina, calcium carbonate, mica, zinc oxide, titanium oxide, mica, talc, kaolin, metal oxides, metal fibers, iron, lead and metal powder. Fillers such as: Carbon materials such as carbon fibers, carbon black, graphite, carbon nanotubes, and fullerene such as C60 (fillers and carbon materials may be collectively referred to as "inorganic components"); antioxidant. Agents, heat stabilizers, UV absorbers, hindered amine light stabilizers (HALS), fingerprint resistant agents, surface hydrophilic agents, antistatic agents, slippering agents, plasticizing agents, mold release agents, defoaming agents, leveling agents, Modifiers such as antisettling agents, surfactants, thixotropy-imparting agents, lubricants, flame retardants, flame retardant aids, polymerization prohibiting agents, fillers, silane coupling agents; coloring of pigments, dyes, hue adjusters, etc. Agents; and curing agents, catalysts, curing accelerators, etc. necessary for the synthesis of monomers or / and their oligomers, or inorganic components; and the like.

In the curable composition of the present invention, the content of the additive is preferably 10 parts by weight or less, preferably 5 parts by weight or less, based on 100 parts by weight of the total of the active energy ray-reactive components. Is more preferable. When the content of the additive is not more than the above upper limit value, the mechanical strength is less likely to decrease due to the decrease in the crosslink density, which is preferable.

The method for incorporating an arbitrary component such as the above-mentioned additive into the curable composition of the present invention is not particularly limited, and examples thereof include conventionally known mixing and dispersion methods. In addition, in order to disperse the arbitrary component more reliably, it is preferable to perform a dispersion treatment using a disperser. Specifically, for example, two-roll, three-roll, bead mill, ball mill, sand mill, pebble mill, ultrasonic mill, sand grinder, seg barrier trimer, planetary stirrer, high-speed impeller disperser, high-speed stone mill, high-speed impact mill. , A method of processing with a kneader, a homogenizer, an ultrasonic disperser, or the like.

The viscosity of the curable composition of the present invention can be appropriately adjusted according to the use and mode of use of the curable composition, but from the viewpoint of handleability, coatability, moldability, three-dimensional formability, etc., it is E-shaped. The viscosity of the viscometer (rotor 1 ° 34'× R24) at 25 ° C. is preferably 10 mPa · s or more, more preferably 30 mPa · s or more, and 50,000 mPa · s or less. It is preferably 10,000 mPa · s or less, further preferably 5,000 mPa · s or less, and particularly preferably 2,000 mPa · s or less. The viscosity of the curable composition can be adjusted, for example, by the content of the urethane (meth) acrylate oligomer according to the present invention, the type of the above-mentioned optional component, the blending ratio thereof, and the like.

Examples of the method for applying the curable composition of the present invention include a bar coater method, an applicator method, a curtain flow coater method, a roll coater method, a spray method, a gravure coater method, a comma coater method, a reverse roll coater method, and a lip coater method. Known methods such as a die coater method, a slot die coater method, an air knife coater method, and a dip coater method can be applied, and among them, the bar coater method and the gravure coater method are preferable.

The curable composition of the present invention preferably has a tensile elastic modulus of 2,000 to 6,000 MPa measured using the curable composition. When this tensile elastic modulus is 2,000 to 6,000 MPa, excellent hardness can be obtained. When the tensile elastic modulus is 2,000 MPa or more, it is preferable from the viewpoint of scratch resistance, stain resistance, wear resistance and the like. On the other hand, when it is 6,000 MPa or less, it is preferable from the viewpoint of three-dimensional processing suitability. The tensile elastic modulus is more preferably 2,500 to 5,500 MPa, still more preferably 3,000 to 5,000 MPa, from the viewpoint of improving the above effect. The film forming method and the measuring method for measuring the tensile elastic modulus are as shown in the examples below.

[Curing / laminated body]
A cured product can be obtained by irradiating the above-mentioned curable composition of the present invention with active energy rays (hereinafter, may be referred to as "cured product of the present invention"). Examples of the active energy ray used for curing the curable composition include infrared rays, visible rays, ultraviolet rays, X-rays, electron beams, α rays, β rays, γ rays and the like. From the viewpoint of equipment cost and productivity, it is preferable to use an electron beam or ultraviolet rays, and as a light source, an electron beam irradiation device, an ultra-high pressure mercury lamp, a high pressure mercury lamp, a medium pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, Ar. Lasers, He-Cd lasers, solid-state lasers, xenon lamps, high-frequency induction mercury lamps, sunlight and the like are suitable.

The irradiation amount of the active energy ray can be appropriately selected according to the type of the active energy ray. For example, when it is cured by electron beam irradiation, the irradiation amount is preferably 1 to 15 Mrad. Further, when it is cured by irradiation with ultraviolet rays, it is preferably 50 to 1,500 mJ / cm2.

When it is cured, it may be under any atmosphere of air or an inert gas such as nitrogen or argon. Further, irradiation may be performed in a closed space between the film or glass and the metal mold.

The thickness of the cured film of the present invention is appropriately determined according to the intended use, but the lower limit is preferably 1 μm, more preferably 2 μm. The upper limit is preferably 100 μm, more preferably 50 μm, and particularly preferably 20 μm. When the film thickness is at least the above lower limit value, the designability and functionality after three-dimensional processing tend to be good, while when the film thickness is at least the above upper limit value, the internal curability and the three-dimensional processing suitability tend to be good. Tends to be good.

Further, by forming the above-mentioned cured product on the substrate, a laminated body can be obtained (hereinafter, may be referred to as "laminated body of the present invention"). The laminate of the present invention is not particularly limited as long as it has a layer made of the cured product of the present invention, and a layer other than the substrate and the cured product of the present invention is placed between the substrate and the cured product of the present invention. It may have it, or it may have it on the outside. Further, the laminated body may have a plurality of layers of a base material and a cured product of the present invention.

As a method for obtaining a laminated body having a plurality of cured products, a method of laminating all the layers in an uncured state and then curing with an active energy ray, and a method of curing or semi-curing the lower layer with an active energy ray. A known method such as a method of applying an upper layer and curing with active energy rays again, or a method of applying each layer to a release film or a base film and then laminating the layers in an uncured or semi-cured state is applied. Although it is possible, from the viewpoint of enhancing the adhesion between layers, a method of laminating in an uncured state and then curing with active energy rays is preferable. As a method of laminating in an uncured state, known methods such as sequential coating in which the lower layer is applied and then the upper layer is applied in layers, and simultaneous multi-layer coating in which two or more layers are simultaneously applied from multiple slits are applied. It is possible, but not limited to this.

Examples of the base material include polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyolefins such as polypropylene and polyethylene, various plastics such as nylon, polycarbonate and (meth) acrylic resin, glass, and metals. Of these, polyethylene terephthalate is preferable. Further, the shape of these base materials may be a flat one such as a film shape or a sheet shape, or may be formed into various shapes.

The laminate of the present invention is particularly preferably produced as a cured film by the following method. Preferred methods for producing a cured film are a step of applying the curable composition of the present invention onto a substrate, a step of irradiating the curable composition with active energy rays to obtain a cured product, and a step of stretching the cured product. It is due to going through. Since the urethane (meth) acrylate oligomer of the present invention has a stretchability after curing that can follow the deformation during three-dimensional processing, it exhibits good stretchability in the step of stretching the cured product. , The obtained cured film has particularly good suitability for deformation during three-dimensional processing.

In the present invention, in the above-mentioned method for producing a cured film, the steps of applying the curable composition onto a substrate and the steps of irradiating the curable composition with active energy rays to obtain a cured product are described. , It can be done under the above-mentioned conditions. Further, in this method for producing a cured film, the step of stretching the cured product can be usually heated and stretched under the conditions of 60 to 200 ° C., preferably 100 to 180 ° C. As this stretching method, a known method can be used, and for example, any method such as insert molding, in-mold molding, overlay molding, blow molding, vacuum forming and the like can be used.

The urethane (meth) acrylate oligomer of the present invention, the cured product obtained by using the curable composition, and the laminate can be suitably used as a coating substitute film. For example, it can be effectively applied to various materials such as interior / exterior building materials, automobiles, home appliances, and information and electronic materials. In particular, the cured film of the present invention is useful as a decorative film using this as a top coat layer.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the following examples. The values of various manufacturing conditions and evaluation results in the following examples have meanings as preferable values of the upper limit or the lower limit in the embodiment of the present invention, and the preferable range is the above-mentioned upper limit or lower limit value. , The range specified by the combination of the values of the following examples or the values of the examples may be used.

[Measurement method of physical properties / characteristics]
The methods for measuring and evaluating the physical properties and characteristics of the urethane (meth) acrylate oligomer and the cured film in the following Examples and Comparative Examples are as follows.

<Physical characteristics of urethane (meth) acrylate oligomer>
1-1) Weight average molecular weight (Mw), number average molecular weight (Mn) of urethane (meth) acrylate oligomer
GPC (Tosoh's "HLC-8120GPC") using tetrahydrofuran (THF) as the solvent, polystyrene as the standard sample, and TSKgel superH1000 + H2000 + H3000 as the column, at a liquid feeding rate of 0.5 mL / min and a column oven temperature of 40 ° C. , The weight average molecular weight and the number average molecular weight (GPC measurement value) of the urethane (meth) acrylate oligomer were measured.

<Physical characteristics of cured film>
2-1) Evaluation of handleability (uncured) A coating film obtained by applying a curable tree on a polyethylene terephthalate film with a bar coater to form a coating film, and then drying at 120 ° C. for 30 seconds. The handling property when uncured was evaluated by the degree of sticking (blocking resistance) when the films were laminated. This coating film was allowed to stand at 23 ° C. and a relative humidity of 55% for 12 hours or more. Next, a polyethylene terephthalate film (untreated type) was superposed on the surface of the coating film, and a load of 1 kg / cm2 was applied at 23 ° C. and a relative humidity of 55% for 12 hours to separate the coating film from the untreated surface of the polyethylene terephthalate film. It was blocked. After unloading, the ratio of the area where blocking occurred to the total area under pressure was visually evaluated according to the following criteria.
○: No blocking part ○-: Blocking area ratio ≤ 10%
Δ: 10% <blocking area ratio ≤ 30%
Δ-: 30% <blocking area ratio ≤ 50%
×: 50% <blocking area ratio

2-2) Evaluation of coating film appearance (after curing) The coating film appearance of the cured film laminated on the polyethylene terephthalate obtained by the film forming method I described later was visually evaluated according to the following criteria.
◯: No abnormalities such as foreign matter, wrinkles, and wrinkled skin are found on the surface of the coating film with a uniform film thickness. Abnormalities such as loose skin are seen ×: Abnormalities such as foreign matter, wrinkles, and loose skin are seen on the surface of the coating film.

2-3) Evaluation of Abrasion Resistance The haze value measured before the scratch resistance test was defined as H1 for the cured film laminated on the polyethylene terephthalate obtained by the film forming method I described later. On the other hand, under an atmosphere of 23 ° C. and 55% RH, a weight of 200 gf (per area 4 cm2) was placed on a dry cloth (for cotton-JIS L 0803 compliant dyeing fastness test), and the polyethylene terephthalate obtained by the above film forming method I was used. The cured film surface laminated on the surface was rubbed 50 times with a Gakushin wear tester (manufactured by Toyo Seiki Co., Ltd.), and the haze value measured immediately after that was taken as H2. The difference between H2 and H1 (ΔH (ΔH = H2-H1)) was determined and evaluated according to the following criteria. In the above, the haze value was measured using a haze meter (“HAZE METER HM-65W” manufactured by Murakami Color Technology Research Institute Co., Ltd.) in accordance with JIS K7105.
◯: ΔH ≦ 2.5
◯-: 2.5 <ΔH ≦ 4.5
Δ: 4.5 <ΔH ≦ 6.5
Δ-: 6.5 <ΔH ≦ 8.5
×: 8.5 <ΔH

2-4) Evaluation of stain resistance (after curing) Sunscreen cream (NIVEA SUN Protect Face manufactured by Nivea-Kao Co., Ltd.) using the cured film obtained by the film-forming method I or film-forming method III described later and the stretched film after curing. Essence milk) (hereinafter referred to as a contaminant) was brought into contact with the product, allowed to stand, and then the contaminant was wiped off with a degreased cotton containing water, and the degree of contamination was visually evaluated. The evaluation film and its contact conditions and evaluation criteria are as follows.
(1) 0.005 g / cm2 was brought into contact with the cured film obtained by the film forming method I and allowed to stand at 80 ° C. for 1 hour. Contact 005 g / cm2 and allow to stand at 23 ° C. for 4 hours. (3) Contact 0.005 g / cm2 to the cured stretched membrane obtained by the film forming method III and allow to stand at 40 ° C. for 4 hours. The evaluation criteria are as follows.
○: No contaminated part ○ －: (Contaminated area area ratio) ≦ 10%
Δ: 10% <(Contaminated area ratio) ≤ 30%
Δ-: 30% <(Contaminated area ratio) ≤ 50%
×: 50% <(Contaminated area ratio)

2-5) Evaluation of elastic modulus (after curing) The cured film of the film forming method II described later is cut into a width of 10 mm, and the temperature is 23 ° C. using a Tensilon tensile tester (“RTC-1210A” manufactured by Orientec). The tensile elastic modulus was measured by conducting a tensile test under the conditions of humidity 55% RH, tensile speed 50 mm / min, and chuck distance 50 mm. More specifically, the straight line connecting the stress at 0% elongation and the stress at 0.5% elongation of the stress-strain curve (SS curve) obtained by conducting a tensile test under the above conditions is extended to 100. The stress converted at the time of% elongation was taken as the tensile elastic modulus. If it was 2,000 to 6,000 MPa, it was evaluated that the mechanical strength was good.

2-6) Evaluation of stretchability (after curing) The cured film of the film forming method II described later is cut into a width of 10 mm, and the temperature is 140 using a Tensilon tensile tester (“MX2-500N” manufactured by Imada Co., Ltd.). The elongation at break was measured by stretching under the conditions of ° C., a tensile speed of 40 mm / min, and a distance between chucks of 40 mm, and evaluated according to the following criteria.
⊚: Elongation 100% or more ○: Elongation 60% or more and less than 100% ×: Elongation less than 60%

[Raw materials / solvents]
The raw materials and solvents used in Examples and Comparative Examples and their abbreviations are as follows. (Compound (A): Polyisocyanate)
IPDI: Isophorone diisocyanate (Evonik Degussa Japan Co., Ltd. product name "
VESTANAT IPDI ")

(Compound (B): chain aliphatic diol having 2 to 5 carbon atoms)
EG: Ethylene glycol

(For comparison with compound (B): chain aliphatic diol having 6 carbon atoms)
1,6-HD: 1,6-hexanediol

(Compound (C): Polyfunctional (meth) acrylate having a hydroxyl group)
V-300: Osaka Organic Co., Ltd. Product name Viscoat (registered trademark) 300 (Pentaerythritol triacrylate 40-40% by weight and pentaerythritol tetraacrylate 35-40% by weight mixture (catalog value) (OH value: 120 mgKOH / g) )
The OH group equivalent (molecular weight per hydroxyl group) 468 was calculated from the OH value: 120 mgKOH / g, and it was assumed that all the components consisted of pentaerythritol triacrylate (PET3A) and pentaerythritol tetraacrylate (PET4A). It was calculated as PET4A = 298 / (468-298) = 64/36 (weight ratio).

(For comparison with compound (C): monofunctional (meth) acrylate having a hydroxyl group)
HEA: 2-hydroxyethyl acrylate

(Organic solvent)
MEK: Methyl ethyl ketone (SP value: 9.0)
IPA: Isopropyl alcohol (SP value: 11.5)

[Example 1]
In a four-necked flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, 163 g of IPDI, 40 g of ethylene glycol, 203 g of methyl ethyl ketone, and 0.02 g of bismastris (2-ethylhexanoate). It was put in and reacted for 9 hours while heating at 80 ° C. in an oil bath. After completion of the reaction, the mixture was cooled to 60 ° C., 0.25 g of bismuth tris (2-ethylhexanoate), 0.15 g of methylhydroquinone and 96 g of methylethylketone were further added, and 96 g of V-300 (PET3A: 61 g / PET4A: 35 g). The reaction was started by dropping. The reaction was carried out in an oil bath at 70 ° C. for 10 hours, and after confirming the end point of the reaction by the disappearance of the peak derived from the isocyanate (NCO) group in the infrared absorption spectrum, 400 g of methyl ethyl ketone was added and the curable resin was added. The composition was obtained. The weight average molecular weight and the number average molecular weight of the urethane acrylate oligomer in the obtained curable composition were measured by the method of 1-1) above. The results obtained are shown in Table 1.

(Calculation of urethane bond amount)
The urethane bond amount of the urethane acrylate oligomer was calculated using the following values. -Number of moles of IPDI: 0.73 mol (= 163 g (molecular weight of IPDI) / 222 (molecular weight of IPDI))
-Number of moles of EG: 0.64 mol (= 40 g (molecular weight of EG) / 62 (molecular weight of EG))-Number of moles of PET3A: 0.20 mol (= 61 g (load amount of PET3A) / 298 (PET3A) Molecular weight))
-Number of isocyanate groups: 1.47 eq (= 0.73 mol (number of moles of IPDI) x 2 (number of isocyanate group functional groups))
-Number of hydroxyl groups: 1.49eq (= 0.64 mol (number of moles of EG) x 2 (number of moles of hydroxyl group) + 0.20 (number of moles of PET3A) x 1 (number of hydroxyl group functional groups)

Since PET3A is not included in the constituents of the urethane (meth) acrylate oligomer in the excessive number of hydroxyl groups (0.02eq (= 1.49eq-1.47eq)), PET3A: 0.18 mol is calculated for the urethane bond amount. ((0.20eq-0.02eq) / number of hydroxyl group functional groups: 1) was used for calculation.
(Urethane bond amount)
= 1.47eq (the smaller value of the total equivalent number of isocyanate groups and the total equivalent number of total functional groups that react with isocyanate groups such as hydroxyl groups and amino groups) / (163 g + 40 g + 0.18 mol × 298)
≒ 5.8 × 10-3eq / g

(Calculation of (meth) acryloyl group amount)
The amount of (meth) acryloyl group of the urethane acrylate oligomer was calculated as follows.
((Meta) acryloyl group amount)
= 0.18 eq (0.20 mol (number of moles of hydroxyalkyl poly (meth) acrylate excluding the amount of excess added component) −0.02 mol × 3 (number of (meth) acryloyl groups)) / (163 ( IPDI component amount) +40 (EG component amount) +0.18 mol x 298 (PET3A component amount))
≒ 2.1 × 10-3eq / g

(Film formation method I)
The curable tree is coated on a polyethylene terephthalate film with a bar coater to form a coating film, dried at 120 ° C. for 30 seconds, and accelerated using an electron beam irradiator (CB175, manufactured by Eye Graphic). The dry coating film was irradiated with an electron beam under the conditions of a voltage of 165 kV and an irradiation dose of 5 Mrad, and further cured at 23 ° C. for one day to form a cured film, and a cured film having a thickness of about 5 μm was laminated on polyethylene terephthalate. Obtained a membrane. The obtained cured film was evaluated for the physical properties of 2-2) to 2-4). These results are shown in Table 1.

(Film formation method II)
The curable composition is coated on a polyethylene terephthalate film with a bar coater to form a coating film, dried at 120 ° C. for 30 seconds, and accelerated by an electron beam irradiator (CB175, manufactured by Eye Graphic). The dry coating film is irradiated with an electron beam under the conditions of 165 kV and an irradiation dose of 5 mad, and further cured at 23 ° C. for one day to form a cured film, and then the cured film is peeled off from the polyethylene terephthalate film to cure the film to a thickness of about 30 μm. Obtained a membrane. The obtained cured film was evaluated for the physical properties of 2-5) and 2-6). These results are shown in Table 1.

(Film formation method III)
The cured film of the above-mentioned film forming method I is cut into a width of 10 mm, and using a Tensilon tensile tester (“MX2-500N” manufactured by Imada Co., Ltd.), the temperature is 140 ° C., the tensile speed is 40 mm / min, and the distance between chucks is 40 mm. The film was stretched by 20 mm (50% elongation) under the above conditions to obtain a stretched film after curing. The obtained cured stretched film was evaluated for the physical properties of 2-4) above. The results are shown in Table 1.

[Example 2]
In a four-necked flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, 184 g of IPDI, 45 g of ethylene glycol, 230 g of methyl ethyl ketone, and 0.02 g of bismastris (2-ethylhexanoate) were added. It was put in and reacted for 9 hours while heating at 80 ° C. in an oil bath. After completion of the reaction, the mixture was cooled to 60 ° C., 0.25 g of bismuth tris (2-ethylhexanoate), 0.15 g of methylhydroquinone and 70 g of methylethylketone were further added, 11 g of HEA and 59 g of V-300 (PET3A: 38 g / g). PET4A: 21 g) Dropped to initiate the reaction. The reaction was carried out in an oil bath at 70 ° C. for 10 hours, and after confirming the end point of the reaction by the disappearance of the peak derived from the isocyanate (NCO) group in the infrared absorption spectrum, 400 g of methyl ethyl ketone was added to form a curable composition. I got something.

With respect to the urethane acrylate oligomer in the obtained curable composition, the weight average molecular weight and the number average molecular weight were measured in the same manner as in Example 1, and the urethane bond amount and the (meth) acryloyl group amount were calculated. Further, the curable composition was formed into a film in the same manner as in Example 1 and the physical characteristics of 2-1) to 2-6) were evaluated. These results are shown in Table 1.

[Example 3]
In a four-necked flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, 190 g of IPDI, 50 g of ethylene glycol, 240 g of methyl ethyl ketone, and 0.02 g of bismastris (2-ethylhexanoate) were added. It was put in and reacted for 9 hours while heating at 80 ° C. in an oil bath. After completion of the reaction, the mixture was cooled to 60 ° C., 0.25 g of bismuth tris (2-ethylhexanoate), 0.15 g of methylhydroquinone and 60 g of methylethylketone were further added, and 60 g of V-300 (PET3A: 38 g / PET4A: 22 g). The reaction was started by dropping. The reaction was carried out in an oil bath at 70 ° C. for 10 hours, and after confirming the end point of the reaction by the disappearance of the peak derived from the isocyanate (NCO) group in the infrared absorption spectrum, 200 g of methyl ethyl ketone and 200 g of isopropyl alcohol were added. , A curable composition was obtained.

With respect to the urethane acrylate oligomer in the obtained curable composition, the weight average molecular weight and the number average molecular weight were measured in the same manner as in Example 1, and the urethane bond amount and the (meth) acryloyl group amount were calculated. Further, the curable composition was formed into a film in the same manner as in Example 1 and the physical characteristics of 2-1) to 2-6) were evaluated. These results are shown in Table 1.

[Comparative Example 1]
In a four-necked flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, 140 g of IPDI, 31 g of ethylene glycol, 170 g of methyl ethyl ketone, and 0.02 g of bismastris (2-ethylhexanoate) were added. It was put in and reacted for 9 hours while heating at 80 ° C. in an oil bath. After completion of the reaction, the mixture was cooled to 60 ° C., 0.25 g of bismuth tris (2-ethylhexanoate), 0.15 g of methylhydroquinone and 130 g of methylethylketone were further added, and 130 g of V-300 (PET3A: 83 g / PET4A: 47 g). The reaction was started by dropping. The reaction was carried out in an oil bath at 70 ° C. for 10 hours, and after confirming the end point of the reaction by the disappearance of the peak derived from the isocyanate (NCO) group in the infrared absorption spectrum, 400 g of methyl ethyl ketone was added to form a curable composition. I got something.

With respect to the urethane acrylate oligomer in the obtained curable composition, the weight average molecular weight and the number average molecular weight were measured in the same manner as in Example 1, and the urethane bond amount and the (meth) acryloyl group amount were calculated. Further, the curable composition was formed into a film in the same manner as in Example 1 and the physical characteristics of 2-1) to 2-6) were evaluated. These results are shown in Table 1.

[Comparative Example 2]
In a four-necked flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, 214 g of IPDI, 51 g of ethylene glycol, 265 g of methyl ethyl ketone, and 0.03 g of bismastris (2-ethylhexanoate) were added. It was put in and reacted for 9 hours while heating at 80 ° C. in an oil bath. After completion of the reaction, the mixture was cooled to 60 ° C., 0.06 g of bismuth tris (2-ethylhexanoate), 0.15 g of methylhydroquinone and 35 g of methylethylketone were further added, and 35 g of HEA was added dropwise to initiate the reaction. The reaction was carried out in an oil bath at 70 ° C. for 10 hours, and after confirming the end point of the reaction by the disappearance of the peak derived from the isocyanate (NCO) group in the infrared absorption spectrum, the methyl ethyl ketone 400
G was added to obtain a curable composition.

With respect to the urethane acrylate oligomer in the obtained curable composition, the weight average molecular weight and the number average molecular weight were measured in the same manner as in Example 1, and the urethane bond amount and the (meth) acryloyl group amount were calculated. Further, the curable composition was formed into a film in the same manner as in Example 1 and the physical characteristics of 2-1) to 2-6) were evaluated. These results are shown in Table 1.

[Comparative Example 3]
142 g of IPDI, 65 g of 1,6-hexanediol, 207 g of methyl ethyl ketone, and bismastris (2-ethylhexanoate) in a four-necked flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer. 0.02 g was added and reacted for 9 hours while heating at 80 ° C. in an oil bath. After completion of the reaction, the mixture was cooled to 60 ° C., 0.25 g of bismuth tris (2-ethylhexanoate), 0.15 g of methylhydroquinone and 93 g of methylethylketone were further added, and 93 g of V-300 (PET3A: 59 g / PET4A: 34 g) was added. The reaction was started by dropping. The reaction was carried out in an oil bath at 70 ° C. for 10 hours, and after confirming the end point of the reaction by the disappearance of the peak derived from the isocyanate (NCO) group in the infrared absorption spectrum, 400 g of methyl ethyl ketone was added to form a curable composition. I got something.

With respect to the urethane acrylate oligomer in the obtained curable composition, the weight average molecular weight and the number average molecular weight were measured in the same manner as in Example 1, and the urethane bond amount and the (meth) acryloyl group amount were calculated. Further, the curable composition was formed into a film in the same manner as in Example 1 and the physical characteristics of 2-1) to 2-6) were evaluated. These results are shown in Table 1.

[Evaluation results]
From the results shown in Table 1, the following can be seen by comparing Examples 1 to 3 with Comparative Examples 1 to 3. First, Comparative Example 1 is an example in which the value is smaller than the urethane bond amount in the urethane (meth) acrylate oligomer of the present invention and the value of the (meth) acryloyl group amount is large. In comparison, the handleability (when uncured) and stretchability were poor. Further, Comparative Example 2 is an example in which "HEA" is used instead of the compound (C), but the wear resistance and the stain resistance after curing are higher than those of Examples 1 to 3. It was bad. Further, Comparative Example 3 is an example in which the value is smaller than the urethane bond amount in the urethane (meth) acrylate oligomer of the present invention, but the handling property (when uncured) is compared with Examples 1 to 3. ), Stain resistance and stretchability after curing and stretching were poor.

The urethane (meth) acrylate oligomer of the present invention, the cured product obtained by using the curable composition, and the laminate can be suitably used as a coating substitute film. For example, it can be effectively applied to various materials such as interior / exterior building materials, automobiles, home appliances, and information and electronic materials. In particular, the cured film of the present invention is useful as a decorative film using this as a top coat layer.

Claims (9)

It is obtained by reacting at least the following compound (A), compound (B) and compound (C), and has a urethane bond amount of 5.2 × 10 ^-3 to 10.0 × 10 ^-3 eq / g, (meth) acryloyl.
The base weight is 0.8 × 10 ^-3 to 3.0 × 10 ^-3 eq / g , the weight average molecular weight (Mw) is 500 to 19,000, and the fracture of the cured film measured under the following conditions. Elongation is 60% or more
Urethane ( meth) acrylate oligomer.
Compound (A): Polyisocyanate Compound (B): Chain aliphatic diol having 2 to 5 carbon atoms Compound (C): Polyfunctional (meth) acrylate having a hydroxyl group
Measurement conditions: The cured film is cut to a width of 10 mm, the temperature is 140 ° C, the tensile speed is 40 mm / min, and the cha
The elongation at break was measured by stretching under the condition that the distance between the hooks was 40 mm. The urethane (meth) acrylate oligomer according to claim 1, which contains at least ethylene glycol as the compound (B). The urethane according to claim 1 or 2, which is obtained by reacting the compound (A) with the compound (B) to obtain a urethane prepolymer and then reacting the compound (C) with the urethane prepolymer. Meta) Acrylate oligomer. The compound (C) may contain a monofunctional (meth) acrylate having a hydroxyl group.
The urethane (meth) acrylate oligomer according to any one of claims 1 to 3. A curable composition containing the urethane (meth) acrylate oligomer according to any one of claims 1 to 4 and an organic solvent. The curable composition according to claim 5 , wherein the solubility parameter of the organic solvent is 8.0 to 11.5. The curable composition according to claim 6 , wherein the solid content concentration is 5 to 90% by weight. A cured product obtained by irradiating the curable composition according to claim 6 or 7 with active energy rays. A laminate obtained by applying the curable composition according to any one of claims 5 to 7 to a substrate and irradiating the substrate with active energy rays to cure the composition.