JP2021134290A - Active energy ray-curable resin composition, adhesive composition and adhesive - Google Patents

Abstract

To provide an active energy ray-curable resin composition having adhesion to various members, especially good adhesive strength when formed into an adhesive by using a urethane(meth)acrylate-based compound obtained using a raw material derived from a plant.SOLUTION: There is provided an active energy ray-curable resin composition comprising a urethane (meth)acrylate-based compound (A) which is a reaction product of a polyol (a1), a polyvalent isocyanate (a2) and a hydroxyl group-containing (meth)acrylate (a3), wherein the polyol (a1) is a polyol derived from castor oil having an average functional group number of 2.5 or less and the polyvalent isocyanate (a2) is a polyvalent isocyanate (a2) having an isocyanate group bonded to a primary carbon atom and an isocyanate group bonded to a secondary carbon atom.SELECTED DRAWING: None

Description

The present invention relates to an active energy ray-curable resin composition, and more specifically, contains a urethane (meth) acrylate-based compound made of a plant-derived raw material, and has adhesion to various members, particularly an adhesive. It relates to an active energy ray-curable resin composition having a good adhesive strength when it is used.

Conventionally, urethane (meth) acrylate compounds obtained by reacting diol compounds such as polyester diols and polyether diols, diisocyanate compounds such as isophorone diisocyanate and diphenylmethane diisocyanate, and hydroxyl group-containing (meth) acrylate compounds such as hydroxyethyl acrylate have been active. Known as an energy ray-curable resin composition, it is used in applications such as paints, coating agents, adhesives, and adhesives.

However, many urethane (meth) acrylate-based compounds are composed of petroleum-derived raw materials, and the current situation is that they are not considered for environmental problems such as global warming.
In addition, while research on urethane (meth) acrylate-based compounds using plant-derived raw materials is being actively conducted, urethane (meth) acrylate-based compounds using castor oil-derived polyols, which are plant-derived raw materials, have been proposed. (See, for example, Patent Documents 1 to 3).

Japanese Unexamined Patent Publication No. 2000-26555 Special Publication No. 58-5949 Japanese Unexamined Patent Publication No. 1-113478

However, in the active energy ray-curable resin compositions containing urethane (meth) acrylate compounds in Patent Documents 1 to 3, the number of functional groups of each of the castor oil is as high as about 2.7, and gelation and storage during the reaction are carried out. Due to concerns about stability at the time, there are restrictions on the types of diisocyanates that can be used, and as a result, the adhesives that can be obtained are also inferior in adhesive strength. there were.

The castor oil is an oil and fat containing a triester compound of linolenic acid and glycerin. Of the fatty acids constituting the entire triester compound, linolenic acid is contained in an amount of about 90 mol%, and the others are oleic acids having no hydroxyl group. , Linoleic acid, linolenic acid and the like are contained, so that the average number of functional groups of castor oil is about 2.7.

Therefore, under such a background, the present invention uses a urethane (meth) acrylate-based compound made of a plant-derived raw material, and has adhesiveness to various members, particularly good adhesive strength when used as an adhesive. It is an object of the present invention to provide an active energy ray-curable resin composition, and to provide a pressure-sensitive adhesive composition using the active energy ray-curable resin composition, and further to provide a pressure-sensitive adhesive.

However, as a result of intensive studies to solve the above problems, the present inventor has an activity containing a urethane (meth) acrylate-based compound which is a reaction product of a polyol, a polyisocyanate, and a hydroxyl group-containing (meth) acrylate. In the energy ray-curable resin composition, a polyol derived from castor oil having an average functional group number of 2.5 or less is used as a polyol component, and an isocyanate group bonded to a primary carbon and an isocyanate bonded to a secondary carbon are used as a polyhydric isocyanate component. By using a polyhydric isocyanate having a group, it was found that it is suitable for the environment but has good adhesion to various members, especially when it is used as an adhesive, and completed the present invention. bottom.

That is, the gist of the present invention is an active energy containing a urethane (meth) acrylate compound (A) which is a reaction product of a polyol (a1), a polyhydric isocyanate (a2) and a hydroxyl group-containing (meth) acrylate (a3). In the linear curable resin composition, the polyol (a1) is a polyol derived from castor oil having an average functional group number of 2.5 or less, and the polyhydric isocyanate (a2) is a secondary isocyanate group bonded to a primary carbon. The present invention relates to an active energy ray-curable resin composition, which is a polyvalent isocyanate having an isocyanate group bonded to carbon.

Further, the present invention relates to a pressure-sensitive adhesive composition comprising the active energy ray-curable resin composition and a pressure-sensitive adhesive obtained by curing the pressure-sensitive adhesive composition.

Since castor oil (including purified ones), which is a polyol component constituting a urethane (meth) acrylate compound, usually has an average number of functional groups of about 2.7, it is directly reacted with a polyhydric isocyanate. In that case, it is easy to gel during the reaction and it is difficult to obtain the desired urethane (meth) acrylate compound, or even if the desired urethane (meth) acrylate is obtained, the storage stability is poor and it cannot be handled in practice. To do. Therefore, a polyol derived from castor oil whose average number of functional groups has been reduced by a dehydration reaction or the like may be used, but even with this, not all molecules have two hydroxyl groups, and one having 1 to 3 hydroxyl groups. Are mixed, and there are still concerns about gelation and storage stability due to the trifunctional polyol. As described above, it is often avoided to use castor oil as the polyol component of the urethane (meth) acrylate-based compound. However, in the present invention, a polyol derived from castor oil having a reduced average number of functional groups is intentionally used. Further, by using a polyvalent isocyanate component having a different class of isocyanate groups, that is, a polyvalent isocyanate having an isocyanate group bonded to a primary carbon and an isocyanate group bonded to a secondary carbon, the reaction is carried out. It was found that a urethane (meth) acrylate-based compound can be obtained satisfactorily without gelation during storage, and an active energy ray-curable resin composition having high adhesive strength can be obtained when used as a pressure-sensitive adhesive. It is.

The active energy ray-curable resin composition of the present invention is a polyvalent compound having a polyol (a1) derived from castor oil having an average functional group number of 2.5 or less, an isocyanate group bonded to a primary carbon, and an isocyanate group bonded to a secondary carbon. It contains a urethane (meth) acrylate compound (A) which is a reaction product of an isocyanate (a2) and a hydroxyl group-containing (meth) acrylate (a3). Therefore, although it is suitable for the environment, it has good adhesion to various members, especially when it is used as an adhesive, and various coating agents, paints, inks, adhesives, etc. An active energy ray-curable resin composition that can be applied to applications. In particular, the active energy ray-curable resin composition of the present invention is useful as an adhesive because it has good adhesive strength.

Hereinafter, embodiments for carrying out the present invention will be specifically described, but the present invention is not limited thereto.

In the present invention, (meth) acrylic means acrylic or methacryl, and (meth) acrylate means acrylate or methacrylate, respectively.

The active energy ray-curable resin composition of the present invention contains a urethane (meth) acrylate-based compound (A), and preferably further contains an ethylenically unsaturated monomer (B).
Hereinafter, each component will be described.

<Urethane (meth) acrylate compound>
The urethane (meth) acrylate compound (A) in the present invention is a reaction product of a polyol (a1), a polyhydric isocyanate (a2), and a hydroxyl group-containing (meth) acrylate.

The polyol (a1) used in the present invention is a castor oil-derived polyol having an average functional group number of 2.5 or less, and a more preferable average number of functional groups is 2.3 or less, more preferably 2.1 or less, and particularly preferably 2.0. It is as follows. If the average number of functional groups is too large, gelation occurs during the reaction, and the storage stability of the urethane (meth) acrylate after the reaction deteriorates. The lower limit of the average number of functional groups is usually 1.5.

Castor oil, which is a precursor of the polyol (a1), is an oil or fat containing a triester compound of ricinoleic acid and glycerin. Of the fatty acids constituting the entire triester compound, ricinolenic acid is contained in an amount of about 90 mol%, and the others contain oleic acid, linoleic acid, linolenic acid and the like having no hydroxyl group. Therefore, the average number of functional groups of castor oil is about 2.7. Further, since castor oil is derived from plants and contains a large amount of impurities, it is preferable to use castor oil refined by distillation or the like. Furthermore, since unsaturated bonds are contained in fatty acids such as ricinoleic acid, it is preferable to use hydrogenated castor oil.

In the present invention, as the castor oil-derived polyol (a1) having an average functional group number of 2.5 or less, the castor oil is partially dehydrated, and a part of ricinoleic acid is replaced with a fatty acid having no hydroxyl group such as oleic acid. Examples thereof include those obtained by partially esterifying the hydroxyl group of ricinoleic acid with a monocarboxylic acid. Among these, it is preferable to use a castor oil-derived polyol obtained by partially dehydrating castor oil because it can be easily obtained.

The polyvalent isocyanate (a2) used in the present invention is a polyvalent isocyanate having an isocyanate group bonded to a primary carbon and an isocyanate group bonded to a secondary carbon, and thus having a different class of isocyanate groups. By using isocyanate, even in the reaction with the above-mentioned castor oil-derived polyol (a1), the reaction proceeds without gelation, and after the reaction with the hydroxyl group-containing (meth) acrylate, good adhesive strength is obtained. A urethane (meth) acrylate-based compound having can be obtained.

Examples of such multi-valent isocyanate (a2) include aliphatic poly-isocyanates such as lysine diisocyanate; and alicyclic poly-isocyanates such as isophorone diisocyanate; These can be used alone or in combination of two or more.
Among these, alicyclic polyvalent isocyanate is preferable, and isophorone diisocyanate is more preferable, from the viewpoint of adhesive physical properties when used as a pressure-sensitive adhesive.

When a polyvalent isocyanate having only an isocyanate group bonded to a primary carbon or a polyvalent isocyanate having only an isocyanate group bonded to a secondary carbon is used as the polyhydric isocyanate, gelation may occur during the reaction. However, the storage stability is deteriorated, and the object of the present invention cannot be achieved.
On the other hand, in the case of the present invention using a polyvalent isocyanate having an isocyanate group bonded to a primary carbon and an isocyanate group bonded to a secondary carbon, the chain extension reaction is suppressed by breaking the symmetry of the reaction. It is considered that the storage stability is improved without gelation during the reaction.

Examples of the hydroxyl group-containing (meth) acrylate (a3) used in the present invention include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl ( Hydroxyalkyl (meth) acrylates such as meta) acrylates and 6-hydroxyhexyl (meth) acrylates, 2-hydroxyethylacryloyl phosphate, 2- (meth) acryloyloxyethyl-2-hydroxypropylphthalate, caprolactone-modified 2-hydroxyethyl (Meta) acrylate, dipropylene glycol mono (meth) acrylate, fatty acid-modified-glycidyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, 2-hydroxy-3- (meth) acrylicloy A hydroxyl group-containing (meth) acrylate containing one ethylenically unsaturated group such as loxypropyl (meth) acrylate; an ethylenically unsaturated group such as glycerindi (meth) acrylate and 2-hydroxy-3-acryloyl-oxypropyl methacrylate. Pentaerythritol tri (meth) acrylate, caprolactone-modified pentaerythritol tri (meth) acrylate, ethylene oxide-modified pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, Examples thereof include hydroxyl group-containing (meth) acrylates containing three or more ethylenically unsaturated groups such as caprolactone-modified dipentaerythritol penta (meth) acrylate and ethylene oxide-modified dipentaerythritol penta (meth) acrylate. These can be used alone or in combination of two or more.

Among these, a hydroxyl group-containing (meth) acrylate containing one ethylenically unsaturated group is preferable, and a hydroxyalkyl (meth) acrylate is preferably used, particularly from the viewpoint of tacky properties when used as a pressure-sensitive adhesive. Hydroxyalkyl (meth) acrylates having 1 to 4 carbon atoms in the alkyl group, particularly 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate, are preferable.

The urethane (meth) acrylate compound (A) in the present invention can be obtained by reacting the above components (a1) to (a3). The production method may be produced according to a known method. Specifically, it can be manufactured as follows.

for example,
(I) The method of charging the above-mentioned polyol (a1), polyhydric isocyanate (a2), and hydroxyl group-containing (meth) acrylate (a3) into a reactor all at once or separately and reacting them.
(Ii) A method of reacting a hydroxyl group-containing (meth) acrylate (a3) with a terminal isocyanate group-containing reaction product obtained by previously reacting a polyol (a1) with a polyhydric isocyanate (a2).
(Iii) A method of reacting a polyol (a1) with a reaction product obtained by reacting a polyhydric isocyanate (a2) with a hydroxyl group-containing (meth) acrylate (a3) in advance.
However, the method (ii) is preferable from the viewpoint of reaction stability and reduction of by-products.

Regarding the method (ii) above, the reaction between the polyol (a1) and the polyhydric isocyanate (a2) can be reacted using a known reaction means. At that time, for example, the molar ratio of the isocyanate group in the polyhydric isocyanate compound (a2) to the hydroxyl group in the polyol (a1) is usually about 2n: (2n-2) (n is an integer of 2 or more). This leaves an isocyanate group and enables an addition reaction with the hydroxyl group-containing (meth) acrylate (a3).
The molar ratio is preferably n of 3 or more and 15 or less. Further, the lower limit is preferably 4, more preferably 5, and even more preferably 6. The upper limit is preferably 12, more preferably 10, and even more preferably 8. If the molar ratio is too small, the adhesive strength tends to be low when used as an adhesive, and if it is too large, the viscosity of the active energy ray-curable resin composition tends to be high and the handleability tends to be low.

The reaction molar ratio of the terminal isocyanate group-containing reaction product to the hydroxyl group-containing (meth) acrylate (a3) is, for example, that the terminal isocyanate group-containing reaction product has two isocyanate groups and the hydroxyl group-containing (meth) acrylate (a3). When there is one hydroxyl group, the terminal isocyanate group-containing reaction product: hydroxyl group-containing (meth) acrylate (a3) is usually about 1: 2, and the terminal isocyanate group-containing reaction product has three isocyanate groups. When the hydroxyl group-containing (meth) acrylate (a3) has one hydroxyl group, the terminal isocyanate group-containing reaction product: hydroxyl group-containing (meth) acrylate (a3) is usually about 1: 3.

In the addition reaction between the terminal isocyanate group-containing reaction product and the hydroxyl group-containing (meth) acrylate (a3), the reaction is terminated when the residual isocyanate group content of the reaction system is usually 0.1% by weight or less. Thereby, the urethane (meth) acrylate compound (A) of the present invention can be obtained.

In the present invention, a reaction between a polyol (a1) derived from castor oil having an average number of functional groups of 2.5 or less and a polyhydric isocyanate (a2), a terminal isocyanate group-containing reaction product thereof, and a hydroxyl group-containing (meth) acrylate (a3). In the reaction of, it is also preferable to use a catalyst for the purpose of accelerating the reaction.

Examples of such a catalyst include organic metal compounds such as dibutyltin dilaurate, trimethyltin hydroxide, and tetra-n-butyltin, zinc octylate, tin octylate, cobalt naphthenate, bismuth chloride, and bismuth chloride. Metal salt, triethylamine, benzyldiethylamine, 1,4-diazabicyclo [2,2,2] octane, 1,8-diazabicyclo [5,4,0] undecene, N, N, N', N'-tetramethyl- In addition to amine-based catalysts such as 1,3-butanediamine and N-ethylmorpholine, bismuth nitrate, bismuth bromide, bismuth iodide, bismuth sulfide, etc., organic bismuth compounds such as dibutyl bismuth dilaurate and dioctyl bismuth dilaurate, 2- Ethylhexanoic acid bismuth salt, naphthenic acid bismuth salt, isodecanoic acid bismuth salt, neodecanoic acid bismuth salt, lauric acid bismuth salt, maleic acid bismuth salt, stearate bismuth salt, oleic acid bismuth salt, linoleic acid bismuth salt, bismuth acetate salt, Examples thereof include bismuth-based catalysts such as bismuth-based organic acid bismuth salts such as bismuth libis neodecanoate, bismuth dysalicylic acid bismuth salt, and bismuth dicalcified acid bismuth salt. Among these, dibutyltin dilaurate and 1,8-diazabicyclo [5,4,0] undecene are preferable.

Further, in the reaction between the polyol (a1) and the polyhydric isocyanate (a2), and further in the reaction between the terminal isocyanate group-containing reaction product and the hydroxyl group-containing (meth) acrylate (a3), the functionality that reacts with the isocyanate group. Organic solvents having no group, for example, esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and organic solvents such as aromatics such as toluene and xylene can be used.

The reaction temperature is usually 30 to 90 ° C., preferably 40 to 80 ° C., and the reaction time is usually 2 to 12 hours, preferably 3 to 10 hours.

Thus, the urethane (meth) acrylate compound (A) can be obtained.

In the present invention, the number average molecular weight of the urethane (meth) acrylate-based compound (A) obtained above is preferably 2000 to 15000. It is more preferably 3000 to 13000, still more preferably 4000 to 12000, particularly preferably 5000 to 10000, and particularly preferably 6000 to 8000. If the number average molecular weight is too small, the adhesive strength of the adhesive tends to be low, and if it is too large, the viscosity of the resin composition becomes high, resulting in problems such as poor handleability and gelation. Tend.

The weight average molecular weight of the urethane (meth) acrylate-based compound (A) is preferably 5,000 to 100,000, more preferably 1,000 to 80,000, still more preferably 2,000 to 60,000, and particularly preferably 30,000 to 50,000. If the weight average molecular weight is too small, the adhesive strength of the adhesive tends to be low, and if it is too large, the viscosity of the resin composition becomes high, resulting in problems such as poor handleability and gelation. Tend.

The above number average molecular weight and weight average molecular weight are the number average molecular weight and weight average molecular weight converted into standard polystyrene molecular weight, and are shown on a high performance liquid chromatograph (“ACQUITY APC system” manufactured by Waters), column: ACQUITY APC XT. It is measured by using four series of 450 × 1, ACQUITY APC XT 200 × 1, and ACQUITY APC XT 45 × 2. At that time, when the object to be measured contains the ethylenically unsaturated monomer (B) described later, the number average molecular weight and the weight average molecular weight are obtained by excluding the ethylenically unsaturated monomer (B).

Further, in the present invention, the viscosity at 60 ° C. when the urethane (meth) acrylate compound (A) is diluted to 80% with the ethylenically unsaturated monomer (B) is preferably 20000 mPa · s or less, more preferably. It is preferably 15,000 mPa · s or less, more preferably 10000 mPa · s or less, particularly preferably 8000 mPa · s or less, and particularly preferably 6000 mPa · s or less. If the viscosity is too high, the handleability tends to decrease.
Here, the method for measuring the viscosity is based on an E-type viscometer.

<Ethylene unsaturated monomer (B)>
The ethylenically unsaturated monomer (B) used in the present invention may be an ethylenically unsaturated monomer having one or more ethylenically unsaturated groups in one molecule, and may be, for example, a monofunctional monomer or a bifunctional monomer. Examples include trifunctional or higher functional monomers.

The monofunctional monomer may be a monomer containing one ethylenically unsaturated group, for example, styrene, vinyltoluene, chlorostyrene, α-methylstyrene, methyl (meth) acrylate, ethyl (meth) acrylate, and acrylonitrile. , Vinyl acetate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-phenoxy -2-Hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, glycerin mono (meth) acrylate, glycidyl (meth) acrylate, lauryl (Meta) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, n-butyl (meth) acrylate, hexyl (meth) acrylate, heptyl ( Meta) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, n-stearyl (meth) acrylate, benzyl (meth) acrylate, phenolethylene Oxide-modified (meth) acrylate, nonylphenol propylene oxide-modified (meth) acrylate, half-ester (meth) acrylate of phthalic acid derivatives such as 2- (meth) acryloyloxy-2-hydroxypropyl phthalate, tetrahydrofurfuryl (meth) acrylate, Carbitol (meth) acrylate, benzyl (meth) acrylate, caprolactone-modified 2-hydroxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, allyl (meth) acrylate, acryloylmorpholine, 2-hydroxyethylacrylamide, N-methylol Examples thereof include (meth) acrylamide, N-vinylpyrrolidone, 2-vinylpyridine, 2- (meth) acryloyloxyethyl acid phosphate monoester and the like.

In addition to the monofunctional monomer described above, a Michael adduct of acrylic acid or a 2-acryloyloxyethyl dicarboxylic acid monoester can also be mentioned. Examples of the Michael adduct of acrylic acid include acrylic acid dimer, methacrylic acid dimer, and acrylic acid trimmer. , Methacrylate trimmer, Acrylic acid tetramer, Methacrylate tetramer and the like. Examples of the 2-acryloyloxyethyl dicarboxylic acid monoester, which is a carboxylic acid having a specific substituent, include 2-acryloyloxyethyl succinic acid monoester, 2-methacryloyloxyethyl succinic acid monoester, and 2-acryloyloxyethyl. Examples thereof include phthalic acid monoester, 2-methacryloyloxyethyl phthalic acid monoester, 2-acryloyloxyethyl hexahydrophthalic acid monoester, and 2-methacryloyloxyethyl hexahydrophthalic acid monoester. Further, oligoester acrylate can also be mentioned.

The bifunctional monomer may be a monomer containing two ethylenically unsaturated groups, for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and polyethylene glycol. Di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene 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, 1 , 9-Nonandiol 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, di phthalate Examples thereof include glycidyl ester di (meth) acrylate, hydroxypivalic acid-modified neopentyl glycol di (meth) acrylate, isocyanuric acid ethylene oxide-modified diacrylate, and 2- (meth) acryloyloxyethyl acid phosphate diester.

The trifunctional or higher functional monomer may be a monomer containing three or more ethylenically unsaturated groups. For example, trimethylpropantri (meth) acrylate, pentaerythritol tri (meth) acrylate, and pentaerythritol tetra (meth). Acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tri (meth) acryloyloxyethoxytrimethylol propane, glycerin polyglycidyl ether poly (meth) acrylate, isocyanurate ethylene oxide-modified triacrylate, ethylene Oxide-modified dipentaerythritol penta (meth) acrylate, ethylene oxide-modified dipentaerythritol hexa (meth) acrylate, ethylene oxide-modified pentaerythritol tri (meth) acrylate, ethylene oxide-modified pentaerythritol tetra (meth) acrylate, caprolactone-modified dipentaerythritol Penta (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, caprolactone-modified pentaerythritol tri (meth) acrylate, caprolactone-modified pentaerythritol tetra (meth) acrylate, succinic acid-modified pentaerythritol tri (meth) acrylate, etc. Be done.

Further, as the ethylenically unsaturated monomer (B), a urethane (meth) acrylate compound obtained by reacting a polyisocyanate compound and a (meth) acrylate compound containing one hydroxyl group, a polyisocyanate compound, 1 A urethane (meth) acrylate-based compound obtained by reacting a (meth) acrylate-based compound containing individual hydroxyl groups and a polyol-based compound (however, the urethane (meth) acrylate-based compound (A) is excluded) may be used. ..

Among these ethylenically unsaturated monomers (B), monofunctional monomers are preferable, and monofunctional alicyclic ethylenically unsaturated monomers are particularly preferable, from the viewpoint of adhesive strength as a pressure-sensitive adhesive. Examples of the alicyclic ethylenically unsaturated monomer include cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, and dicyclopentenyl (meth) acrylate, and among them, isobornyl acrylate. Is the most preferable.

These ethylenically unsaturated monomers (B) may be used alone or in combination of two or more. Further, the ethylenically unsaturated monomer (B) may be separately blended with the urethane (meth) acrylate-based compound (A), or may be used as a raw material for producing the urethane (meth) acrylate-based compound (A) at the time of production. Part or all may be present in the system. Further, it may be contained as a reaction solvent in the above reactions (a1) to (a3).

In the present invention, the content of the ethylenically unsaturated monomer (B) is 20 to 400% by weight in terms of the adhesive force when used as an adhesive with respect to 100 parts by weight of the urethane (meth) acrylate-based compound (A). It is preferably 30 to 300 parts by weight, more preferably 40 to 200 parts by weight, particularly preferably 50 to 150 parts by weight, and particularly preferably 60 to 100 parts by weight. If the content of the ethylenically unsaturated monomer (B) is too small or too large, it tends to be difficult to obtain sufficient adhesive strength when used as an adhesive.

<Photopolymerization initiator (C)>
In the present invention, it is preferable to further contain a photopolymerization initiator (C) in order to perform curing by active energy rays more efficiently.

Examples of the photopolymerization initiator (C) include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethylketal, 4- (2-hydroxyethoxy) -phenyl- (2). -Hydroxy-2-propyl) ketone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4-) Morphorinophenyl) butanone, 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone oligomer, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2 -Methyl-1-propane-1-one, 2-hydroxy-1-{4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propane-1-one , 2,2-Dimethoxy-1,2-diphenylethane-1-one, acetophenones such as phenylglycylic acid methyl ester; benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, etc. Classes; benzophenone, methyl o-benzoyl benzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenylsulfide, 3,3', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, 2 , 4,6-trimethylbenzophenone, 4-benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-propenyloxy) ethyl] benzenemethanamineium bromide, (4-benzoylbenzyl) trimethylammonium chloride Benzoyls such as 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino-2-hydroxy). Thioxanthones such as -3,4-dimethyl-9H-thioxanthone-9-one mesochloride; 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4 Acylphosphs such as -trimethyl-pentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide Onoxides; etc. As for these photopolymerization initiators (C), only one kind may be used alone, or two or more kinds may be used in combination.

In addition, as these auxiliaries, triethanolamine, triisopropanolamine, 4,4'-dimethylaminobenzophenone (Michler ketone), 4,4'-diethylaminobenzophenone, 2-dimethylaminoethyl benzoic acid, 4-dimethylaminobenzoic acid Ethyl, 4-dimethylaminobenzoic acid (n-butoxy) ethyl, 4-dimethylaminobenzoate isoamyl, 4-dimethylaminobenzoate 2-ethylhexyl, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanson Etc. can be used together.

Among these, benzyl dimethyl ketal, 1-hydroxycyclohexylphenyl ketone, benzoin isopropyl ether, 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 2-hydroxy-2-methyl-1- It is preferable to use phenylpropane-1-one.

The content of the photopolymerization initiator (C) is 0.1 to 40 parts by weight with respect to 100 parts by weight in total of the urethane (meth) acrylate compound (A) and the ethylenically unsaturated monomer (B). It is preferably 0.5 to 20 parts by weight, more preferably 1 to 10 parts by weight. If the content of the photopolymerization initiator (C) is too small, curing tends to be poor, and if it is too large, solution stability tends to decrease such as precipitation during coating, or embrittlement or coloring. Prone to problems.

Regarding the method for mixing the urethane (meth) acrylate compound (A), the ethylenically unsaturated monomer (B), and the photopolymerization initiator (C) in producing the active energy ray-curable composition obtained in the present invention. Is not particularly limited, and can be mixed by various methods. For example, each component can be mixed all at once, or any component can be mixed first and then the remaining components can be appropriately selected.

Thus, the active energy ray-curable resin composition of the present invention is obtained.
Further, if necessary, a surface conditioner, a leveling agent, a polymerization inhibitor and the like can be further added.

The surface conditioner is not particularly limited, and examples thereof include alkyd resin and the like.
Such an alkyd resin has an action of imparting a film-forming property at the time of coating and an action of improving the adhesiveness with a metal thin film surface.

As the leveling agent, a known general leveling agent can be used as long as it has an effect of imparting wettability to the substrate of the coating liquid and an effect of lowering the surface tension. For example, a silicone-modified resin, a fluorine-modified resin, etc. An alkyl-modified resin or the like can be used. These can be used alone or in combination of two or more.

Examples of the polymerization inhibitor include p-benzoquinone, naphthoquinone, tolucinone, 2,5-diphenyl-p-benzoquinone, hydroquinone, 2,5-di-t-butylhydroquinone, methylhydroquinone, methoxyphenol, and 2,6-di. Examples thereof include -t-butyl-p-cresol, mono-t-butylhydroquinone, and pt-butylcatechol. Of these, methoxyphenol and 2,6-di-t-butyl-p-cresol are preferable. These can be used alone or in combination of two or more.

The active energy ray-curable resin composition of the present invention is applied on various substrates, dried when containing an organic solvent, and then cured by irradiating with active energy rays.

The method for applying the active energy ray-curable resin composition is not particularly limited, and for example, spray, shower, dipping, roll, spin, curtain, flow, slit, die, gravure, comma, dispenser, etc. Wet coating methods such as screen printing, inkjet printing and the like can be mentioned.

The above coating can be carried out by blending an organic solvent and adjusting the viscosity, if necessary, and examples of the organic solvent include methanol, ethanol, propanol, n-butanol, i-butanol and the like. Alcohols, acetone, methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone and other ketones, ethyl cellosolve and other cellosolves, toluene, xylene and other aromatics, propylene glycol monomethyl ether and other glycol ethers, methyl acetate, ethyl acetate, etc. Examples thereof include acetate esters such as butyl acetate and diacetone alcohols. These organic solvents may be used alone or in combination of two or more.

When the active energy ray-curable resin composition is a solid or a high-viscosity liquid, the hot-melt method or the like is applied by the above method after heating the active energy ray-curable resin composition to reduce the viscosity. Can also be mentioned.

As such active energy rays, for example, far ultraviolet rays, ultraviolet rays, near ultraviolet rays, rays such as infrared rays, electromagnetic waves such as X-rays and γ-rays, electron beams, proton rays, neutron rays and the like can be used. Curing by ultraviolet irradiation is advantageous because of the availability and price of the irradiation device. When electron beam irradiation is performed, it can be cured without using the photopolymerization initiator (C).

As a method of curing by ultraviolet irradiation, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a chemical lamp, a non-electrode discharge lamp, an LED, etc. that emit light in the wavelength range of 150 to 450 nm are used. It suffices to irradiate about 30 to 3000 mJ / cm ^2.
After the irradiation with ultraviolet rays, heating can be performed as necessary to complete the curing.

The film thickness of the cured coating film is usually 1 to 300 μm, preferably 2 to 250 μm, and more preferably 5 to 200 μm in consideration of light transmission so that the photopolymerization initiator (C) reacts uniformly.

In the present invention, the glass transition temperature (Tg) of the cured product of the active energy ray-curable resin composition is preferably −30 ° C. or higher, more preferably −30 to 50 ° C., still more preferably −20 to 45 ° C., particularly. It is preferably −10 to 40 ° C., particularly preferably 0 to 30 ° C. When the glass transition temperature (Tg) deviates from the above range, the adhesive strength tends to decrease when the adhesive is used.

The method for measuring the glass transition temperature (Tg) is as follows.
That is, the active energy ray-curable resin composition is applied to an easily adhesive-treated polyethylene terephthalate (PET) film (thickness 125 μm) so that the film thickness after curing is 100 μm using an applicator, and a desktop UV irradiation device (top UV irradiation device). Ultraviolet rays under the condition of 80 W / cm (high pressure mercury lamp) x 18 cm H x 1.9 m / min x 3 Pass (cumulative irradiation amount 2,400 mJ / cm ^{2) by "Conveyor type desktop irradiation device" manufactured by iGraphics Co., Ltd.} A test piece having a length of 20 mm and a width of 3 mm was cut out from an adhesive sheet for measuring adhesive strength prepared by irradiating and curing the test piece, and using the test piece, a dynamic viscoelasticity measuring device manufactured by IT Measurement Control Co., Ltd. Using the tensile mode of "DVA-225", the measurement was performed at a frequency of 1 Hz, a heating rate of 3 ° C./min, and a strain of 0.1%. The ratio (tan δ) of the loss elastic modulus) is obtained, and the maximum peak temperature of this tan δ is defined as the glass transition temperature (° C.).

The gel fraction after curing of the active energy ray-curable resin composition is preferably 10% by weight or more, more preferably 20 to 98% by weight, and further preferably 30 from the viewpoint of durability and adhesive strength. It is ~ 97% by weight, particularly preferably 40 ~ 95% by weight. If the gel fraction is too low, the cohesive force tends to decrease and the durability tends to decrease. If the gel fraction is too high, there is a concern that the adhesive strength will decrease due to the increase in cohesive force.

The gel fraction is a measure of the degree of cross-linking, and is calculated by, for example, the following method. That is, a cured coating film sheet (without a separator) formed by forming a cured coating film on a polymer sheet (for example, PET film or the like) as a base material is wrapped with a 200 mesh SUS wire net and contained in toluene. The gel fraction is defined as the weight percentage of the insoluble cured coating film component remaining in the wire net after immersion with respect to the weight of the cured coating film component before immersion at 23 ° C. for 24 hours. However, the weight of the base material is deducted.

The active energy ray-curable resin composition of the present invention uses castor oil derived from a plant and is an active energy ray-curable resin composition with a reduced environmental load. The biomass ratio can be expressed by the ratio of the number of carbons derived from plants to the total carbon contained in the active energy ray-curable resin composition, preferably 30 C% or more (C% represents the ratio of carbon). It is more preferably 40 C% or more, further preferably 50 C% or more, particularly preferably 60 C% or more, and particularly preferably 70 C% or more. The biomass ratio is a raw material constituting an active energy ray-curable resin composition of a polyhydric isocyanate (a2), a hydroxyl group-containing (meth) acrylate (a3), and an ethylenically unsaturated monomer (B) in addition to the polyol (a1). It can be calculated by calculating the ratio of the carbon number of the raw material derived from the plant from the total carbon number. More accurately, it can also be measured by the method specified in ASTM D6866.

Examples of the base material to which the active energy ray-curable resin composition obtained in the present invention is applied include a polyolefin resin, a polyester resin, a polycarbonate resin, an acrylonitrile butadiene styrene copolymer (ABS), and a polystyrene resin. , Polycarbonate resin, etc. and their molded products (film, sheet, cup, etc.), metal base material (metal vapor deposition layer, metal plate (copper, stainless steel (SUS304, SUSBA, etc.), aluminum, zinc, magnesium, etc.)), Examples thereof include glass and the like and their composite base materials.

In the present invention, the active energy ray-curable resin composition containing the urethane (meth) acrylate-based compound (A) has adhesiveness to various members, particularly good adhesive strength when used as an adhesive. It is an active energy ray-curable resin composition that can be applied to various uses such as coating agents, paints, inks, and adhesives, and is particularly useful as an adhesive because it has good adhesive strength.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. In the example, "part" and "%" mean a weight standard.
The number average molecular weight, weight average molecular weight, viscosity, and gel fraction of the urethane (meth) acrylate compound were measured according to the above-mentioned method.

The following "HS 2G-120" was used as the castor oil-derived polyol (a1) having an average functional group number of 2.5 or less. In the comparative example, the following "ELA-DR" was used.
-"HS 2G-120": Dehydrated castor oil manufactured by Toyokuni Oil Co., Ltd. (hydroxyl value 121.7 mgKOH / g, average number of functional groups 2.0)
-"ELA-DR": Castor oil manufactured by Toyokuni Oil Co., Ltd. (hydroxyl value 161.0 mgKOH / g, average number of functional groups 2.7)

<Example 1>
[Preparation of urethane acrylate (A-1)]
In a flask equipped with an internal thermometer, a stirrer, and a cooling tube, 85.5 parts of isophorone diisocyanate (IPDI) as a polyhydric isocyanate (a2) and a polyol (a1) derived from castor oil having an average functional group number of 2.5 or less are "HS". 236.5 parts of "2G-120", 90 parts of butyl acrylate (BA) as ethylenically unsaturated monomer (B-1), 0.02 part of 2,6-di-tert-butyl cresol as a polymerization inhibitor and 4-methoxy. 0.18 parts of phenol and 0.14 parts of dibutyltin dilaurate as a reaction catalyst were added, and the mixture was reacted at 70 ° C. After the residual isocyanate group is 2.6% or less, 37.9 parts of 4-hydroxybutyl acrylate (4HBA) is added as the hydroxyl group-containing acrylate (a3) and reacted at 70 ° C. to obtain 0.1% of the residual isocyanate group. The reaction was terminated when the results were as follows to obtain a composition containing urethane acrylate (A-1). Table 1 shows the number average molecular weight, weight average molecular weight, and dispersity of the obtained urethane acrylate (A-1).

Further, with respect to the composition containing the urethane acrylate (A-1) and the ethylenically unsaturated monomer (B-1) obtained above, after storing at 60 ° C. for 7 days, it is visually confirmed whether or not the composition is gelled. The results were evaluated according to the following criteria. The evaluation results are shown in Table 1.
(Evaluation criteria)
○ ・ ・ ・ No gelation × ・ ・ ・ With gelation

[Preparation of active energy ray-curable resin composition]
With respect to 100 parts of the total amount of the urethane acrylate (A-1) and the ethylenically unsaturated monomer (B-1), 35 parts of isobornyl acrylate (IBOA) as the ethylenically unsaturated monomer (B-2), light Four parts of 1-hydroxy-cyclohexyl-phenyl-ketone were uniformly mixed as the polymerization initiator (C) to obtain an active energy ray-curable resin composition.
The adhesiveness of the obtained active energy ray-curable resin composition was evaluated as follows.

[Adhesive]
(Preparation of adhesive sheet for measuring adhesive strength)
The obtained active energy ray-curable resin composition is applied to an easily adhesive-treated polyethylene terephthalate (PET) film (thickness 125 μm) so that the film thickness after curing is 100 μm, using an applicator, and a desktop UV irradiation device is used. Under the condition of 80 W / cm (high-pressure mercury lamp) x 18 cm H x 1.9 m / min x 3 Pass (integrated irradiation amount 2,400 mJ / cm ^{2) with (Igraphics, "conveyor type desktop irradiation device")} By irradiating with ultraviolet rays and curing, an adhesive sheet for measuring adhesive strength was obtained.

(Test method)
After cutting the obtained adhesive sheet for measuring adhesive strength to 25 mm × 100 mm, it reciprocates twice on a stainless steel plate (SUS304BA plate) as an adherend using a 2 kg rubber roller in an atmosphere of 23 ° C. and 50% relative humidity. The test piece was prepared by crimping. After allowing this test piece to stand in the same atmosphere for 30 minutes, a 180-degree peeling test was performed at a peeling speed of 0.3 m / min, and the adhesive strength (N / 25 mm) was measured. The measurement results are shown in Table 1.

<Examples 2 to 4>
In Example 1, a polyol, a polyisocyanate, a hydroxyl group-containing acrylate, an ethylenically unsaturated monomer (B-1), an ethylenically unsaturated monomer (B-2), a reaction catalyst, a type and amount of a polymerization inhibitor, and the amount charged. The same procedure was carried out except that the residual isocyanate group at the time of addition of the hydroxyl group-containing acrylate was changed as shown in Table 1.
The adhesiveness of the obtained active energy ray-curable resin composition was evaluated in the same manner as in Example 1. The results are shown in Table 1.

<Comparative Examples 1 and 2>
In Example 1, the polyol, polyisocyanate, hydroxyl group-containing acrylate, ethylenically unsaturated monomer (B-1), reaction catalyst, type and amount of polymerization inhibitor, and residual isocyanate group when the hydroxyl group-containing acrylate is added are used. The procedure was the same except that the changes were made as described in Table 1.
However, all of them gelled in the middle of the reaction, and the desired urethane acrylate could not be obtained.

From the results in Table 1 above, the active energy ray-curable resin compositions of Examples 1 to 4 are a polyol (a1) derived from castor oil having an average number of functional groups of 2.5 or less, an isocyanate group bonded to a primary carbon, and a secondary. Urethane acrylate obtained by using a polyvalent isocyanate (a2) having an isocyanate group bonded to carbon has excellent storage stability and good adhesive strength when used as an adhesive.
On the other hand, Comparative Example 1 uses the same polyhydric isocyanate as in Example as the polyhydric isocyanate (a2), but since the average number of functional groups of the castor oil-derived polyol (a1) is larger than 2.5, Gelation occurred during the reaction, and the desired urethane acrylate could not be obtained.
Further, in Comparative Example 2, a polyol (a1) derived from castor oil having an average number of functional groups of 2.5 or less was used, but since the polyhydric isocyanate (a2) used a polyhydric isocyanate having only a primary isocyanate group, the reaction was in progress. Gelation did not give the desired urethane acrylate.

The active energy ray-curable resin composition of the present invention contains a plant-derived polyol (a1) derived from castor oil having an average functional group number of 2.5 or less, an isocyanate group bonded to a primary carbon, and an isocyanate group bonded to a secondary carbon. It contains a urethane (meth) acrylate compound (A) which is a reaction product of a polyhydric isocyanate (a2) and a hydroxyl group-containing (meth) acrylate (a3). Therefore, although it is suitable for the environment, it has good adhesion to various members, especially when it is used as an adhesive, and various coating agents, paints, inks, adhesives, etc. It is an active energy ray-curable resin composition applicable to applications, and in particular, the active energy ray-curable resin composition of the present invention is useful as a pressure-sensitive adhesive because it has good adhesive strength.

Claims (10)

An active energy ray-curable resin composition containing a urethane (meth) acrylate compound (A), which is a reaction product of a polyol (a1), a polyhydric isocyanate (a2), and a hydroxyl group-containing (meth) acrylate (a3). hand,
The polyol (a1) is a castor oil-derived polyol having an average functional group number of 2.5 or less.
An active energy ray-curable resin composition, wherein the polyvalent isocyanate (a2) is a polyvalent isocyanate having an isocyanate group bonded to a primary carbon and an isocyanate group bonded to a secondary carbon. The active energy ray-curable resin composition according to claim 1, wherein the polyvalent isocyanate (a2) is an alicyclic polyvalent isocyanate. The active energy ray-curable resin composition according to claim 1 or 2, wherein the polyol (a1) is dehydrated castor oil. The active energy ray-curable resin composition according to any one of claims 1 to 3, wherein the urethane (meth) acrylate compound (A) has a number average molecular weight of 2000 to 15000. The active energy ray-curable resin composition according to any one of claims 1 to 4, further comprising an ethylenically unsaturated monomer (B). The active energy ray-curable resin composition according to claim 5, wherein the ethylenically unsaturated monomer (B) is an alicyclic ethylenically unsaturated monomer. The active energy ray-curable resin composition according to any one of claims 1 to 6, further comprising a photopolymerization initiator (C). The active energy ray-curable resin composition according to any one of claims 1 to 7, wherein the gel fraction of the cured product of the active energy ray-curable resin composition is 10% by weight or more. A pressure-sensitive adhesive composition comprising the active energy ray-curable resin composition according to any one of claims 1 to 8. A pressure-sensitive adhesive according to claim 9, wherein the pressure-sensitive adhesive composition is cured.