JP5344794B2 - Active energy ray-curable coating resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a quick-curing low-viscosity polyfunctional acrylic monomer having excellent adhesiveness to attain the required properties of coating agents while preventing the warpage of a substrate and the cracking of the coating film in the case of forming a coating film even without using an acrylate-modified or non-modified silica or an acrylate having a urethane skeleton. <P>SOLUTION: The active energy ray-curable resin composition contains a (meth)acrylate of a compound obtained by the addition of an alkylene oxide (a 2-4C alkylene oxide at an added molar number of 4-40) to a polyglycerol (having an average polymerization degree of 2-10). <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention includes various functional films such as an antireflection film, various films such as an anti-scratch film, various molded products such as automobile bumpers, home appliances and information equipment terminals, and coating layers for high-density information recording media such as CDs and DVDs. The present invention relates to a coating resin composition for forming.

  Conventionally, it has been common to use a thermosetting or solvent volatilization type resin composition for the preparation of a coating film, but the thermosetting type is not suitable for a substrate having no heat resistance, and a solvent. The volatilization type has a problem that the load on the environment is large. Therefore, in recent years, a coating method using a resin composition curable by irradiation with active energy rays has been developed in various fields.

  However, the curing due to the irradiation of active energy rays is accompanied by shrinkage, and problems that warp (warp) and crack (crack) occur in the cured product have been pointed out. It has been reported to use a composition (Patent Document 1) containing fine particle silica modified with (meth) acrylate and a composition (Patent Document 2) containing an acrylate having a urethane skeleton.

  However, when the above-mentioned fine particle silica is used, it is not always easy to uniformly disperse in the composition, and uniform dispersion stability is lacking unless the composition is diluted with various organic solvents. In addition, acrylates having a urethane skeleton also increase in viscosity due to a tendency to increase the molecular weight, and it is difficult to produce a thin coating film that is difficult to use in operation unless the composition is diluted with various organic solvents. . As described above, the essential meaning of the work environment / environmental compatible technology that can be cured without using the organic solvent of the active energy ray curable resin composition is not at present.

In curing by irradiation with active energy rays, not only performance but also products with better production efficiency and workability are demanded, and in particular, those with fast curing and low compound viscosity are demanded. In general, it is effective to use a polyfunctional (meth) acrylate compound such as dipentaerythritol hexaacrylate to increase the curing rate. However, when these were used, a product satisfying performance such as viscosity and cure shrinkage was not obtained although the curability was good.
JP 2006-063244 A JP 2005-330403 A

  Even when not using the acrylate modified or unmodified silica or acrylate having a urethane skeleton, when creating a coating film, excellent adhesion while preventing warping of the substrate and cracking of the coating film itself, In recent years, a fast-curing low-viscosity polyfunctional acrylic monomer capable of obtaining properties as a coating agent has been desired.

  As a result of diligent research, the present inventors have found that a compound obtained by adding an alkylene oxide (an alkylene oxide having 2 to 4 carbon atoms and 4 to 40 added moles) to polyglycerin (average polymerization degree 2 to 10). It came to solve the said subject with the active energy ray hardening-type resin composition for coating characterized by containing (meth) acrylate.

  By containing the (meth) acrylate of the present invention, the curing speed is high, the base film does not warp, the coating film does not crack, and the coating resin composition can be used without using an organic solvent. An active energy ray-curable coating resin composition that can keep the viscosity low can be obtained.

  In this invention, (meth) acrylate of the compound which added alkylene oxide (C2-C4 alkylene oxide and 4-40 addition moles) with respect to polyglycerol (average polymerization degree 2-10) is used. Although various compounds can be synthesized according to the polymerization degree of polyglycerol, the type and number of added moles of alkylene oxide, and the reaction ratio of (meth) acrylate, it will be described below.

  The polyglycerin used for the acrylate used in the present invention has an average degree of polymerization of 2 to 10 obtained with a hydroxyl group equivalent, and preferably has an average degree of polymerization of 4 to 10. When the average degree of polymerization is 1, that is, glycerin, the curing rate is not preferable because it is slow, and when the average degree of polymerization is larger than 10, it is not preferable because there are various problems in manufacturing such as difficulty in washing in the manufacturing process.

  Examples of the alkylene oxide used in the acrylate used in the present invention include ethylene oxide, propylene oxide, and butylene oxide. Ethylene oxide or propylene oxide is preferable, and ethylene oxide and propylene oxide may be used alone or in combination. The number of added units of alkylene oxide is 4 to 40 mol, preferably 4 to 30 mol, per 1 mol of polyglycerol. When the number of added moles is less than 4 moles, the secondary alcohol of the polyglycerin skeleton increases, making it difficult to react with (meth) acrylate. Conversely, when the number of added moles is increased from 40, washing with water during the production process is required. This is not preferable because there are various problems in production such as being difficult.

  About the reaction rate of the (meth) acrylate used by this invention, it is preferable to make it react 70% or more among the hydroxyl groups of the alkylene oxide adduct of polyglycerol. If it is less than 70%, the reaction rate is slow, and there are various problems in production, such as difficulty in washing with water during the production process.

  In addition, (meth) acrylate used by this invention is 10 to 99 weight% normally with respect to a coating composition, Preferably it is 20 to 90 weight%, More preferably, 30 to 80 weight% is mix | blended. If it is less than this range, the viscosity of the coating composition in the solvent-free system is particularly high, and it becomes difficult to produce a thin coating film on the work.

  The active energy ray-curable coating resin composition of the present invention does not prevent the use of other (meth) acrylic monomers alone or in combination of two or more in addition to the (meth) acrylate used in the present invention. Examples of other acrylic monomers include tetrahydrofurfuryl (meth) acrylate, carbitol (meth) acrylate, phenoxyethyl (meth) acrylate, isobornyl (meth) acrylate, acryloylmorpholine, 2-ethylhexyldiethoxy (meth) acrylate, Hydrogenated dicyclopentadiene (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, tricyclodecane di (meth) acrylate, tripropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpro Polyethoxytri (meth) acrylate, trimethylolpropane polypropoxytri (meth) acrylate, glycerin polypropoxytri (meth) acrylate, bisphenol A polyethoxydi (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) ) Monomers such as acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol penta and hexa (meth) acrylate mixtures, dipentaerythritol polyethoxyhexa (meth) acrylate, dipentaerythritol polypropoxyhexa (meth) acrylate Can be mentioned.

  The resin composition of the present invention can be cured by a known method. An active energy ray is a general term for electron beams, X-rays, ultraviolet rays, electron beams with high energy such as visible light in a low wavelength region, or electromagnetic waves, and ultraviolet rays are preferable because of the simplicity and spread of ordinary devices. There are many types of devices that can irradiate ultraviolet rays, but they can be arbitrarily selected. Moreover, it is also possible to use a blue LED as energy such as visible light on the low wavelength region side.

  In the present invention, it is necessary to use a photopolymerization initiator when curing with ultraviolet rays. The photopolymerization initiator may be any known photopolymerization initiator, but is required to have good storage stability after blending. Examples of such a photopolymerization initiator include benzoins, acetophenones, thioxanthones, ketals, benzophenones, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and the like, alone or in combination of two or more. be able to. When it is necessary to use a photopolymerization initiator, the amount used is usually 0.1 to 15% by weight of the composition, preferably 0.5 to 10% by weight, and more preferably 1 to 7% by weight.

  Examples of benzoins include benzoin ethyl ether, benzoin butyl ether, and benzoin isopropyl ether. Examples of acetophenones include acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (Methylthio) phenyl] -2-morpholino-propan-1-one, N, N-dimethylaminoacetophenone and the like. Examples of thioxanthones include 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, and the like. Examples of ketals include benzyl dimethyl ketal and acetophenone dimethyl ketal. Examples of benzophenones include benzophenone, methylbenzophenone, 4,4'-bisdiethylaminobenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide.

  Furthermore, a photosensitizer can be used alone or in combination of two or more. Examples of the photosensitizer include tertiary amines such as N, N-dimethylaminobenzoic acid ethyl ester, N, N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, and triethanolamine. can give.

  If desired, the resin composition of the present invention comprises non-reactive polymer resins such as organic solvents such as toluene, hexane, ethyl acetate, methyl ethyl ketone, methanol and ethanol, polyester elastomers, polyurethane elastomers and acrylic polymers; polydiallyl phthalate, poly Reactive polymer resins such as diallyl isophthalate; leveling agents, antifoaming agents, silane coupling agents, antioxidants, UV absorbers, colorants, light stabilizers, polymerization inhibitors, etc .; calcium carbonate, talc Inorganic fillers such as silica and barium sulfate can be used in combination.

  The active energy ray-curable resin composition is applied to the surface of various substrates, and then cured by irradiating with active energy rays such as ultraviolet rays. The composition can be applied on a wide range of substrates including paper, hard and flexible plastics, metal substrates, cement, glass, stone, ceramic, wood, etc.

Hereinafter, the present invention will be specifically described by way of examples. In addition, this invention is not limited to a following example.
<Synthesis Example 1>
A compound obtained by adding 176 g (4 mol) of ethylene oxide to 166 g (1 mol) of diglycerin was reacted with 317 g (4.4 mol) of acrylic acid at 85 ° C. for 10 hours, and then toluene and a large amount of water and unreacted An amount of caustic to neutralize acrylic acid was added, the organic layer was taken out with a separatory funnel, and toluene was distilled off with an evaporator to obtain an acrylate reaction product of diglycerin ethylene oxide (4 mol) adduct. The viscosity of the product was 230 mPa · s (25 ° C.), and the reaction ratio of acrylic acid obtained from the saponification value was 80% with respect to the hydroxyl group. Hereinafter, the obtained compound is referred to as A1.

<Synthesis Example 2>
Except having changed ethylene oxide into 264 g (6 mol), the same reaction as in Synthesis Example 1 was performed to obtain an acrylate reaction product of diglycerin ethylene oxide (6 mol) adduct. The viscosity of the product was 240 mPa · s (25 ° C.), and the reaction ratio of acrylic acid determined from the saponification value was 87% with respect to the hydroxyl group. Hereinafter, the obtained compound is referred to as A2.

<Synthesis Example 3>
Except having changed ethylene oxide 880g (20 mol) and reaction time into 12 hours, it reacted similarly to the synthesis example 1, and obtained the acrylate reaction material of the diglycerin ethylene oxide (20 mol) addition product. The viscosity of the product was 350 mPa · s (25 ° C.), and the reaction ratio of acrylic acid determined from the saponification value was 84% with respect to the hydroxyl group. Hereinafter, the obtained compound is referred to as A3.

<Synthesis Example 4>
The same as Synthesis Example 1 except that 166 g (1 mol) of diglycerin was changed to 314 g (1 mol) of tetraglycerin, 264 g (6 mol) of ethylene oxide, 649 g (9 mol) of acrylic acid, and the reaction time was changed to 18 hours. The acrylate reaction product of tetraglycerin ethylene oxide (6 mol) adduct was obtained. The viscosity of the product was 440 mPa · s (25 ° C.), and the reaction ratio of acrylic acid determined from the saponification value was 95% with respect to the hydroxyl group. Hereinafter, the obtained compound is referred to as A4.

<Synthesis Example 5>
166 g (1 mol) of diglycerin is 758 g (1 mol) of decaglycerol, 1056 g (24 mol) of ethylene oxide, 1297 g (18 mol) of acrylic acid, and the reaction time is changed to 18 hours. Reaction was performed to obtain an acrylate reaction product of decaglycerin ethylene oxide (24 mol) adduct. The product had a viscosity of 890 mPa · s (25 ° C.), and the reaction ratio of acrylic acid determined from the saponification value was 93% with respect to the hydroxyl group. Hereinafter, the obtained compound is referred to as A5.

Reference Examples 1 to 3, Examples 4 and 5, and Comparative Examples 1 to 4 were mixed in a formulation as shown in Table 1 (the numerical value represents parts by weight), and various compositions were mixed with photopolymerization initiators. It prepared so that it might melt | dissolve and become uniform and performed various evaluations. Evaluation in the examples was performed by the following method.

  Composition viscosity: The prepared composition was measured with a rotational viscometer. The viscosity was measured at 25 ° C. using a B-type viscometer (BM type; rotor No. 1) manufactured by Tokyo Keiki Co., Ltd. The viscosity of the non-volatile component not containing an organic solvent is desirably 2000 mPa · s or less. This is because it is difficult to form a thin coating film when the viscosity is high.

Curability: The prepared composition was applied on a polycarbonate resin film having a thickness of 100 μm by a bar coater (thickness 15 μm), and then irradiated at a position 20 cm under a light source in which a high-pressure mercury lamp (lamp output 2 kW) was arranged in parallel. Cured. The integrated light quantity (mJ / cm < ² >) until it hardens | cured was calculated | required using the Ushio Electric Co., Ltd. integrated light quantity meter UIT-250 (light-receiving part 365nm).
A: Completely cured at less than 50 mJ / cm ² .
○: Completely cured at 50 mJ / cm ² or more and less than 100 mJ / cm ² .
Δ: Completely cured at 100 mJ / cm ² or more and less than 200 mJ / cm ² .
X: Completely cured at 200 mJ / cm ² or more.

Shrinkage: The warpage of the substrate cured by the above method was visually observed.
○ ····················································································································
X: Warpage is seen in the polycarbonate of the base material.

Adhesiveness: The printed material cured by the above-described method was subjected to a cross-cut-cello tape (registered trademark) peel test described in JIS K 5400.
○ ············ No peeling at 100 mm.
Δ ···· A peeling of less than 30% is observed in 100 mm.
× ········· 30% or more peeled in 100%.

  From the evaluation results in Table 1, the active energy ray-curable coating resin composition of the present invention has a low viscosity without being diluted with an organic solvent, and has a high curing speed and a low adhesion without shrinking the substrate. Is also good.

  By using the coating resin composition of the present invention, a low-viscosity composition can be obtained without using an organic solvent, the coating speed is high, the hardness is high, and there is no warping or cracking of the substrate. Can be created.

Claims (2)

Containing (meth) acrylate of polyglycerol alkylene oxide adduct (addition mole number 4 to 40) obtained by reacting polyglycerol (average polymerization degree 4 to 10) and alkylene oxide (carbon number 2 to 4). An active energy ray-curable resin composition for coating. The resin composition for active energy ray-curable coatings according to claim 1 containing a photopolymerization initiator.