JP2006273939A - Acrylic resin composition of energy ray-curing type and method for producing resin product using the composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition of energy ray-curing type, having a suitable viscosity, when coated, not substantially containing a solvent, and capable of giving a resin product with a high polymerization degree, and to provide a method for producing the resin product using the same. <P>SOLUTION: This acrylic resin composition of energy ray-curing type is compounded of (A) an acrylic rubber and (B) a monomer consisting mainly of a (meth)acrylic acid ester in a weight ratio satisfying: (a):(b)=5:95 to 75:25, wherein the acrylic rubber (A) comprises an acrylic rubber which is obtained by conducting suspension polymerization of the monomer consisting mainly of the (meth)acrylic acid ester, then conducting washing in water, dehydration, and drying, or comprises an acrylic rubber which is obtained by conducting emulsion polymerization of the monomer, then conducting salting-out, washing in water, dehydration, and drying, and has a weight-average molecular weight of ≥100,000. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an acrylic energy ray-curable resin composition and a method for producing a resin product using the composition.

  Conventionally, in order to produce coating resin products such as paints, pressure-sensitive adhesives, adhesives, and hard coat materials, organic solvent resin compositions and water-based emulsion resin compositions have been used.

  In order to obtain a solvent-type highly polymerized acrylic resin composition, it is difficult to obtain a high molecular weight product by solution polymerization. Therefore, an acrylic polymer obtained by a bulk polymerization method, an emulsion polymerization method, a suspension polymerization method, etc. "Acrylic rubber") is dissolved in an organic solvent.

  However, acrylic rubber has a problem that it becomes difficult to dissolve in an organic solvent when the functional group content increases. In addition, when an organic solvent is used, an apparatus for burning or recovering the diffused organic solvent is required, the cost is considerably increased, and there is a concern about the influence on environmental pollution.

  In addition, the water-based emulsion resin composition has a problem that it takes a long time for the drying process because of the large latent heat of vaporization of water, and a problem that the resulting product is whitened or has poor water resistance.

On the other hand, a solution containing acrylic monomers and oligomers as the main component is applied on the base material without using a solvent or dispersion medium, and heat polymerization is performed on the base material, or polymerization and curing is performed with ultraviolet rays or electron beams. A solvent-free resin product of the method has been proposed. However, a certain degree of viscosity is required for coating, but since it has a low viscosity, it must be prepolymerized to have an appropriate viscosity. For example, JP 2001-49200 A describes that a so-called syrup solution is prepared for viscosity adjustment. In this method, a polymer is synthesized at a very low polymerization rate by bulk polymerization, and then a large amount of residual monomer is distilled to separate the polymer, but this method undergoes bulk polymerization that is difficult to control the reaction. There is a problem that a large amount of residual monomer needs to be distilled, viscosity adjustment is difficult and cost is high.
JP 2001-49200 A

  The present invention has been made in view of the above, and provides a resin composition that has solved all the problems of conventional solvent-type, water-based emulsion-type, and useless-type resin compositions, and a method for producing a resin product using the same. This is the issue. In particular, an energy beam curable resin composition that does not substantially contain a solvent (organic solvent or water) and has an appropriate viscosity at the time of application, and can obtain a resin product with a high degree of polymerization. It is an object to provide a product and a method for producing a resin product using the product.

  In order to solve the above-mentioned problem, the energy ray curable resin composition of the present invention is obtained by subjecting a monomer (A) (meth) acrylic ester as a main component to suspension polymerization, washing with water, dehydrating and drying. Acrylic rubber obtained by emulsion polymerization of the obtained acrylic rubber or a monomer mainly composed of (meth) acrylic acid ester, followed by salting out, washing, dehydration, and drying, and having a weight average molecular weight of 100,000 or more And (B) (meth) acrylic acid ester as a main component, and a weight ratio of (a) :( b) = 5: 95 to 75:25 (Claim 1).

  In the energy beam curable resin composition of the present invention, it is preferable that (A) acrylic rubber is soluble in the monomer (B).

  In the energy ray curable resin composition of the present invention, (A) acrylic rubber or (B) monomer has a functional group reactive with a melamine compound, an epoxy compound or an isocyanate compound, or a functional group capable of self-crosslinking. (Claim 3).

  The energy beam curable resin composition of the present invention preferably has a viscosity at 25 ° C. in the range of 1,000 to 100,000 cps (claim 4).

  The energy beam curable resin composition of the present invention may be one or two or more selected from the group consisting of melamine compounds, epoxy compounds and isocyanate compounds as a crosslinking agent. (Claim 5).

  The energy beam curable resin composition of the present invention may contain a photopolymerization initiator and substantially contain no solvent (Claim 6).

  In the method for producing a resin product of the present invention, the energy ray-curable resin composition of the present invention is applied to the support surface with a thickness of 0.01 to 1.0 mm, and then polymerized by irradiation with energy rays. (Claim 7).

  The energy beam curable resin composition of the present invention is different from the prior art such as preparing a high molecular weight acrylic rubber in advance and dissolving it in an organic solvent, and is substantially free of a solvent and used as a support. When applied, it has an appropriate viscosity. By using the energy beam curable resin composition of the present invention, a high molecular weight resin product can be obtained without restrictions on production.

  The energy ray curable resin composition of the present invention can be copolymerized by further adding a monomer having a functional group in any proportion to a monomer mainly composed of (meth) acrylic acid ester that dissolves acrylic rubber. Therefore, an energy ray-curable resin composition having a functional group-containing monomer amount of 7% by weight or more, which was not obtained with a conventional solvent-based acrylic energy ray-curable resin composition, is obtained.

  According to the production method of the present invention, the above-described highly polymerized resin product can be easily obtained by applying the energy beam curable resin composition of the present invention to a support and performing energy beam irradiation. In particular, it is possible to obtain a resin product having an arbitrary degree of polymerization by changing conditions such as the amount of photopolymerization initiator, the irradiation distance of energy rays, and the irradiation time.

  (A) Acrylic rubber used in the present invention is obtained by subjecting a monomer mainly composed of (meth) acrylic acid ester to suspension polymerization, followed by water washing, dehydration and drying, or (meth) acrylic acid ester. The monomer as the main component is obtained by emulsion polymerization, followed by salting out, washing with water, dehydration and drying.

  Suspension polymerization, emulsion polymerization, and subsequent treatment until drying can be performed by a conventionally known method. That is, suspension polymerization is performed by dispersing a monomer in water using a dispersant, and emulsion polymerization is performed by emulsifying the monomer in water using a surfactant. In both cases, the molecular weight can be adjusted with a mercaptan chain transfer agent. The salting-out step is a step of obtaining an acrylic rubber by breaking the emulsion by heating. At this time, a salting-out agent (salt, acid, etc.) is preferably used. The water washing step is performed by dehydrating with a centrifugal dehydrator, sending the rubber into the water tank, and stirring. After washing with water, it is dehydrated with a centrifugal dehydrator (dehydration step) and dried with a dryer (drying step). The drying temperature is usually in the range of 50 to 130 ° C, but is preferably in the range of 80 to 110 ° C.

  Examples of the monomer constituting the above (A) acrylic rubber and (B) the monomer for dissolving the acrylic rubber include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth) (Meth) acrylic esters such as butyl acrylate, (meth) acrylic acid pentyl, (meth) acrylic acid hexyl, (meth) acrylic acid-2-ethylhexyl, (meth) acrylic acid octyl, (meth) acrylic acid nonyl And acrylonitrile is also included. Such monomers can be used alone or in combination. In the present specification, “having (meth) acrylic acid ester as a main component” means that 50% by weight or more of all monomers constituting these components (A) and (B) are those (meth) acrylic acid esters. Or it means acrylonitrile.

  By changing the polymerization degree of the acrylic rubber and / or the composition ratio of the acrylic rubber and the monomer (B) for melting the acrylic rubber, it has a viscosity that can be applied to the support and is substantially free of solvent. A resin composition is obtained.

  The weight average molecular weight of the acrylic rubber is preferably 100,000 or more, more preferably 300,000 to 1,000,000.

  The (A) acrylic rubber and (B) monomer preferably have a functional group reactive with a melamine compound, an epoxy compound or an isocyanate compound, or a functional group capable of self-crosslinking. Examples of functional group-containing monomers used for this purpose include (meth) acrylic acid, carboxyl group-containing vinyl monomers such as itaconic acid, (meth) acrylic acid glycidyl ether, (meth) acrylic acid-2-ethylglycidyl ether Epoxy group-containing vinyl monomers such as (meth) acrylic acid-2-hydroxyethyl, hydroxyl group-containing vinyl monomers such as (meth) acrylic acid-2-hydropropyl, (meth) acrylamide, N- Examples include amide group-containing vinyl monomers such as methylol (meth) acrylamide and N-butoxymethyl (meth) acrylamide, and these can be used alone or in combination of two or more.

  The amount of the functional group-containing monomer is preferably 1 to 10% by weight based on the total amount of acrylic rubber monomer solution. The acrylic rubber having a functional group-containing monomer amount of 7% by weight or less is soluble in monomers having a (meth) acrylic acid ester as a main component from a low polymerization degree to a high polymerization degree.

  When it is desired to form a crosslinked structure in the energy ray curable resin composition of the present invention, a crosslinking agent may be added. Examples of cross-linking agents include melamine compounds such as methylol melamine and butoxymethylol melamine, bisphenol A, epichlorohydrin type epoxy compounds, tolylene diisocyanate, hexamethylene diisocyanate with polyols such as trimethylol propane and hexa Isocyanate compounds such as trimers such as methylene diisocyanate can be used, and these can be used alone or in combination of two or more.

  The amount of the crosslinking agent to be added is usually in the range of 1 to 15 parts by weight, preferably 5 to 10 parts by weight, based on 100 parts by weight of (A) the acrylic rubber and (B) the monomer for dissolving the acrylic rubber. Part range.

  If necessary, a photopolymerization initiator is added to the energy beam curable resin composition of the present invention. As the photopolymerization initiator, acetophenone-based or benzophenone-based ones are preferable. Examples of photopolymerization initiators include 4-phenoxydicycloacetophenone, 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, benzoin, benzoyl methyl ether, benzoin isobutyl ether, benzyl methyl ketal, etc. And a commercially available product can be used. These photopolymerization initiators can be used alone or in combination.

  The amount of the photopolymerization initiator used is usually in the range of 0.01 to 3 parts by weight with respect to 100 parts by weight of the acrylic rubber mainly composed of (meth) acrylic acid ester and the monomer for dissolving the acrylic rubber. Preferably, it is the range of 0.05-2 weight part.

  The energy ray curable resin composition of the present invention may further contain an ultraviolet absorber as necessary. Examples of the ultraviolet absorber include 2,4-hydroxybenzophenone and 2- (2'-hydroxy-5'-methylphenyl) benzotriazole. In addition to these, additives such as pigments can be added depending on the application.

  The energy ray curable resin composition of the present invention preferably has a viscosity at 25 ° C. in the range of 1,000 to 100,000 cps, and more preferably in the range of 2,000 to 30,000 cps.

  The acrylic energy beam curable resin composition containing the photopolymerization initiator of the present invention is applied to the surface of the support in a thickness of 0.1 to 1.0 mm and polymerized by irradiation with energy rays such as ultraviolet rays and electron beams. The reaction proceeds to form a coating layer, and a resin product having an arbitrary degree of polymerization can be produced.

  Examples of the support used here include plastic films such as polyolefin film, polyester film, and vinyl chloride film, paper, metal foil, non-woven fabric, woven fabric (cloth), release film, and the like.

  The irradiation time of the energy beam of ultraviolet rays varies depending on the thickness of the coating layer and the blending amount of the photopolymerization initiator, but is usually 10 seconds to 5 minutes, preferably 10 seconds to 2 minutes.

  A resin product having a low polymerization degree to a high polymerization degree can be obtained by changing the conditions such as the amount of the photopolymerization initiator, the amount of the ultraviolet absorber, the irradiation distance and irradiation time of the energy beam of ultraviolet rays.

  Hereinafter, the acrylic energy ray curable resin composition of the present invention and a method for producing a resin product using the composition will be described more specifically based on the implementation, but the present invention is not limited thereto. .

[Synthesis Example 1 (Synthesis of acrylic rubber A)]
100 parts of a monomer composition comprising 15 parts by weight of butyl acrylate (hereinafter simply referred to as “parts”), 40 parts of methyl methacrylate, 39 parts of ethyl methacrylate, 4 parts of acrylic acid, and 2 parts of 2-hydroxyethyl acrylate are mixed with 200 parts of water. Part, 20 parts of modified PVA as a surfactant and 0.1 part of n-dodecyl mercaptan were stirred to carry out emulsion polymerization. This was salted out using bow glass as a salting-out agent, dehydrated using a centrifugal dehydrator, washed with water, dehydrated, and dried at 100 ° C. to obtain acrylic rubber A. The amount of functional group-containing acrylic ester of acrylic rubber A is 6% by weight.

[Synthesis Example 2 (Synthesis of acrylic rubber B)]
Emulsion polymerization is carried out in the same manner as in Synthesis Example 1 except that a monomer composition comprising 50 parts of butyl acrylate, 44 parts of methyl methacrylate, 4 parts of acrylic acid, and 2 parts of 2-hydroxyethyl acrylate is used, and salting out. Acrylic rubber B was obtained through water washing, dehydration and drying processes. The amount of functional group-containing acrylic ester of acrylic rubber B is 6% by weight.

[Synthesis Example 3 (Synthesis of acrylic rubber C)]
Same as Synthesis Example 1 except that a monomer composition consisting of 38 parts butyl acrylate, 22 parts methyl methacrylate, 34 parts acrylic acid-2-ethylhexyl, 4 parts acrylic acid and 2 parts 2-hydroxyethyl acrylate was used. Emulsion polymerization was performed, and acrylic rubber C was obtained through salting out, washing with water, dehydration, and drying steps. The amount of functional group-containing acrylic ester of acrylic rubber C is 6% by weight.

[Examples 1 to 9]
Acrylic rubber A is dissolved in a monomer mixture having the same composition ratio as acrylic rubber A, and 2.5 parts of acrylic acid and 2.5 parts of 2-hydroxyethyl acrylate are added to obtain 25% solution A. It was. The amount of the functional group-containing acrylic ester in the 25% solution A is 10% by weight of the total amount including the acrylic rubber.

  Acrylic rubber B is dissolved in a monomer mixture having the same composition ratio as that of acrylic rubber B, and 2.5 parts of acrylic acid and 2.5 parts of 2-hydroxyethyl acrylate are further added. Obtained. The amount of the functional group-containing acrylic ester in the 25% solution B is 10% by weight of the total amount including the acrylic rubber content.

  Acrylic rubber C is dissolved in a monomer mixture having the same composition ratio as that of acrylic rubber C, and 2.5 parts of acrylic acid and 2.5 parts of 2-hydroxyethyl acrylate are further added. Obtained. The amount of the functional group-containing acrylic ester in the 25% solution C is 10% by weight of the total amount including the acrylic rubber content.

  A photopolymerization initiator benzoin isopropyl ether was added to 100 parts of these solutions in the number of additions shown in Table 1 to obtain an energy beam curable resin composition. The viscosity of these energy beam curable resin compositions was measured with a BH viscometer (manufactured by Tokyo Keiki). The results are shown in Table 1.

  These energy ray-curable resin compositions were applied to a polyester (polyethylene terephthalate) film at a thickness of 10 μm, and ultraviolet irradiation was performed at three levels of 0.5 minutes, 1.0 minutes, and 2.0 minutes.

  About the obtained film, Tg is measured by a dynamic viscoelasticity measuring apparatus (manufactured by SII), and the molecular weight (weight average molecular weight: Mw) is measured by gel permeation chromatography (GPC, manufactured by Shimadzu Corporation). Went. The results are shown in Table 1.

  As can be seen from the results shown in Table 1, the energy ray curable resin composition of the present invention had a viscosity suitable for coating. In addition, an energy ray-curable resin composition having a functional group-containing monomer content of 7% by weight or more, which has not been obtained with conventional solvent-based highly polymerized acrylic resin products, is obtained, and a high molecular weight resin product can be obtained even with a short irradiation time Obtained.

The energy beam curable resin composition of the present invention can be used as a resin composition for paints, adhesives, pressure-sensitive adhesives, hard coating materials and the like.

Claims (7)

(A) A monomer composed mainly of (meth) acrylic acid ester is subjected to suspension polymerization, followed by washing with water, dehydration and drying, or an emulsion polymerization of a monomer composed mainly of (meth) acrylic acid ester. An acrylic rubber obtained by salting out, washing with water, dehydrating and drying, an acrylic rubber having a weight average molecular weight of 100,000 or more, and a monomer comprising (B) (meth) acrylic acid ester as a main component; The
An energy beam curable resin composition comprising a weight ratio of (a) :( b) = 5: 95 to 75:25.   The energy ray-curable resin composition according to claim 1, wherein the (A) acrylic rubber is soluble in the monomer (B).   The (A) acrylic rubber or the (B) monomer has a functional group reactive with a melamine compound, an epoxy compound or an isocyanate compound, or a functional group capable of self-crosslinking. The energy beam curable resin composition according to 1.   The energy ray curable resin composition according to any one of claims 1 to 3, wherein the viscosity at 25 ° C is in the range of 1,000 to 100,000 cps.   The crosslinking agent according to any one of claims 1 to 4, wherein one or more selected from the group consisting of melamine compounds, epoxy compounds and isocyanate compounds are blended. Energy ray curable resin composition.   The energy ray curable resin composition according to any one of claims 1 to 5, wherein a photopolymerization initiator is blended and substantially no solvent is contained. After applying the energy ray-curable resin composition according to any one of claims 1 to 6 to a support surface with a thickness of 0.01 to 1.0 mm, the energy ray is irradiated and polymerized. A method for producing a resin product characterized by the following.