JP5125100B2 - Method for producing acrylic polymer having polymerizable unsaturated bond - Google Patents

Description

  The present invention relates to a novel and useful method for producing an active energy ray-curable resin and an active energy ray-curable resin composition using the same. More specifically, the present invention provides a cured coating film that has a tack-free surface after volatilization of the solvent, has a good surface condition without adhesion of dust and dust, has excellent curability, and has excellent chemical resistance and flexibility. The present invention relates to an active energy ray-curable resin suitable for an active energy ray-curable resin composition used as a top clear layer for metal products, plastic products, and the like.

  Molded products such as metal parts, plastic products, and woodwork products are often formed with a paint film on the surface of the molded product for the purpose of imparting durability and design. Since molded articles to be painted (hereinafter referred to as objects to be coated) have a wide variety of materials and shapes, spray coating, dip coating methods, and the like that can be applied relatively easily are often used.

  In recent years, an active energy ray-curing type film additive that forms a multilayer coating film by pasting a laminated film in which a film has been applied in advance to form a multilayer coating film on an object to be coated by an adhesive or heat transfer. A decoration method has been proposed (see, for example, Japanese Patent Application Laid-Open No. 6-100640). According to this method, reduction of uncoated paint on the object to be coated during spray coating, reduction of solvent volatilization (improvement of coating environment) and shortening of the coating process (shortening of curing and drying time by active energy ray curing) Can be achieved.

  The laminated film used in the above-mentioned film decoration method is coated with the laminated film, such as coating film properties realized by a coating method such as spray coating, non-adhesiveness, solvent resistance, and the like. Workability for suitably decorating objects is required. However, in the conventional laminated film, it has been difficult to ensure the coating properties and the workability at the same time. That is, when emphasizing the coating film characteristics, the processability is lowered, and when emphasizing processability, it is difficult to ensure the coating film characteristics.

  More specifically, when importance is attached to the processability of the laminated film, for example, it is necessary to impart flexibility to the laminated film so as to follow the shape of the molded product. This flexibility can be achieved by using a laminated film using a resin having a low glass transition temperature, or by reducing the crosslinking density of the laminated film. However, when flexibility is emphasized as described above, there is a problem that it is difficult to secure coating film properties such as non-adhesiveness of the laminated film and a decrease in coating film hardness and a decrease in chemical resistance. .

  Thus, in the past, while ensuring the workability when decorating an object to be coated using a laminated film, a coating level equal to or higher than the coating film properties and design properties realized by the spray coating method described above, etc. It was difficult to obtain film characteristics and design properties.

  The present invention has been made to solve the above-mentioned conventional problems, and its purpose is to ensure excellent design properties and coating film characteristics equal to or higher than those of conventional spray coating methods and the like, and to be coated. Polymerizable unsaturation suitable for active energy ray-curable resin compositions used as the top clear layer of laminated films, with excellent processability such as being able to perform suitable decoration following the shape of the product It is providing the manufacturing method of the acrylic polymer which has a coupling | bonding.

  As a result of intensive studies on the above problems, the present inventors introduced an unsaturated double bond that cures with an active energy ray into an acrylic polymer as a side chain, and the length of the unsaturated double bond. By controlling the thickness, it is possible to achieve both various coating film properties and processability, which were difficult with the prior art, and suitable for active energy ray-curable resin compositions, which have an acrylic unsaturated bond A method for producing a polymer has been found and the present invention has been completed.

  That is, the present invention is characterized by the following items (1) to (7).

  (1) A polymerizable unsaturated compound (a) having at least one epoxy group and one polymerizable unsaturated bond in the molecule, and 1 polymerizable unsaturated bond in the molecule other than the component (a) The epoxy group-containing copolymer (c) obtained by copolymerization with a single polymerizable unsaturated compound (b) has a short-chain unsaturated carboxylic acid (d1) having a molecular weight of less than 150 and a molecular weight of 150 or more. A method for producing an acrylic polymer (A) having a polymerizable unsaturated bond, comprising synthesizing an acrylic polymer (A) by reacting a long-chain unsaturated carboxylic acid (d2).

  (2) The short-chain unsaturated carboxylic acid (d1) and the long-chain unsaturated carboxylic acid (d2) may be 20 mol% or more and 80 mol% or less with respect to the total molar amount (d1 + d2), respectively. The method for producing an acrylic polymer (A) having a polymerizable unsaturated bond as described in (1) above, wherein

  (3) The polymerizable unsaturated as described in (1) or (2) above, wherein the acrylic polymer (A) has a weight average molecular weight in the range of 50,000 to 500,000. A method for producing an acrylic polymer (A) having a bond.

  (4) The reactive unsaturated double bond group contained in the acrylic polymer (A) is in the range of 0.67 mol / kg to 3.3 mol / kg, The manufacturing method of the acrylic polymer (A) which has a polymerizable unsaturated bond in any one of said (1)-(3).

  (5) The polymerizable group according to any one of (1) to (4) above, wherein the epoxy group-containing copolymer (c) has a glass transition temperature of 50 ° C. or higher and 130 ° C. or lower. A method for producing an acrylic polymer (A) having a saturated bond.

  (6) Isocyanato group-containing polymerizable unsaturated compound (e) having one isocyanato group and one or more polymerizable unsaturated bonds in the molecule with respect to the hydroxyl group contained in the acrylic polymer (A). Of the acrylic polymer (A) having a polymerizable unsaturated bond according to any one of the above (1) to (5), wherein 0.1 to 0.8 equivalent is added to cause addition reaction. Production method.

  (7) The acrylic polymer having a polymerizable unsaturated bond according to any one of the above (1) to (6), wherein the acrylic polymer (A) has a hydroxyl value of 30 or more and 125 or less. Production method of polymer (A).

  The acrylic polymer (A) having a polymerizable unsaturated bond produced according to the present invention ensures non-adhesiveness of the coating film before curing, hardness of the coating film after curing, chemical resistance, and excellent workability. Therefore, it is suitable for an active energy ray-curable resin composition. It is particularly suitable for an active energy ray-curable resin composition used for a top clear layer of a laminated film in a film decoration method.

  This application is accompanied by a priority claim based on Japanese Patent Application No. 2004-068170 (filing date: March 10, 2004) previously filed by the same applicant, and these specifications are for reference. Incorporated here.

  Hereinafter, the present invention will be described in detail.

  The method for producing an acrylic polymer (A) having a polymerizable unsaturated bond according to the present invention comprises a polymerizable unsaturated compound (a) having at least one epoxy group and one polymerizable unsaturated bond in the molecule; The epoxy group-containing copolymer (c) obtained by copolymerization with a polymerizable unsaturated compound (b) having one polymerizable unsaturated bond in the molecule other than the component (a) has a molecular weight of 150. Characterized in that an acrylic polymer (A) is synthesized by reacting a short-chain unsaturated carboxylic acid (d1) having a molecular weight of less than 150 and a long-chain unsaturated carboxylic acid (d2) having a molecular weight of 150 or more. It is.

  The acrylic polymer (A) obtained by the present invention polymerizes derivatives of acrylic acid or methacrylic acid (hereinafter collectively referred to as (meth) acrylic acid or (meth) acrylate) in the main chain structure. And having at least one polymerizable short side chain unsaturated double bond group and one long side chain unsaturated double bond group in the side chain bonded to the main chain structure. In addition, these polymerizable unsaturated double bond groups mean substituents that are cross-linked by reaction within a molecule or between molecules, and each is an epoxy group-containing copolymer that is an acrylic polymer (A) precursor. (C) is introduced by reacting the short-chain unsaturated carboxylic acid (d1) and the long-chain unsaturated carboxylic acid (d2).

  In the production method of the present invention, first, a polymerizable unsaturated compound (a) having one or more epoxy groups and one polymerizable unsaturated bond in the molecule and polymerized in the molecule other than the component (a). An epoxy group-containing copolymer (c) is synthesized by copolymerizing a polymerizable unsaturated compound (b) having one polymerizable unsaturated bond.

  The component (a) is not particularly limited as long as it is a polysaturated unsaturated compound having one or more epoxy groups and one polymerizable unsaturated bond in the molecule, and a derivative of acrylic acid or methacrylic acid; It is preferable that it is a compound with an epoxy group containing compound, for example, epoxy group containing (meth) acrylates, such as glycidyl (meth) acrylate and 3,4-epoxycyclohexyl (meth) acrylate, etc. are mentioned, These are independent, Two or more kinds may be used in combination.

  The component (b) is not limited to the component (a) and may be any unsaturated compound having one polymerizable unsaturated bond in the molecule. For example, methyl (meth) acrylate ((meth) acrylate indicates acrylate and methacrylate; the same applies hereinafter), ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl. Alkyl (meth) acrylates such as (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, ethylhexyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, Cyclohexyl (meth) acrylate, Cycloaliphatic (meth) acrylates such as sobornyl (meth) acrylate and dicyclopentanyl (meth) acrylate, aromatic vinyl monomers such as styrene and vinyltoluene, aromatic (meth) acrylates such as phenoxyethyl (meth) acrylate, ethoxy Hydroxy such as ethyl (meth) acrylate, alkoxyalkyl (meth) acrylate such as butoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, etc. Alkoxyalkoxyalkyl (meth) acrylates such as alkyl (meth) acrylate, 2-methoxyethoxyethyl (meth) acrylate and 2-ethoxyethoxyethyl (meth) acrylate, methoxydiethyl Alkoxy (poly) alkylene glycols (meth) acrylate (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, butoxytriethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate, etc. ) Acrylates, pyrenoxide adducts (meth) acrylates, octafluoropentyl (meth) acrylates, N, N-dimethylaminoethyl (meth) acrylates, N, N-diethylaminoethyl (meth) acrylates and other dialkylaminoalkyl (meth) acrylates The mixture which consists of 1 type, or 2 or more types of combinations, etc. is mentioned.

  The component (a) and the component (b) are copolymerized by a known method such as a solution polymerization method in the presence of a radical polymerization initiator to obtain an epoxy group-containing copolymer (c). Here, as these compounding quantities, (a) component is preferably 10 to 60 weights with respect to 100 parts by weight of the total amount of (a) and (b) components {(a) + (b)} Parts, more preferably 20 to 45 parts by weight, and the component (b) is preferably 40 to 90 parts by weight, more preferably 55 to 80 parts by weight. When the component (a) is less than 10 parts by weight, the curability and cured film performance of the coating film obtained when the active energy ray-curable coating material is obtained tend to generally decrease, exceeding 60 parts by weight. And the non-adhesiveness of the coating film tends to decrease.

  The epoxy group-containing copolymer (c) thus obtained preferably has a weight average molecular weight (gel permeation chromatography method, standard polystyrene conversion value) of 30,000 to 200,000, preferably 50,000 to 150. Is more preferable. When the weight average molecular weight of the epoxy group-containing copolymer (c) is less than 30,000, the non-tackiness of the coating film obtained when the acrylic polymer (A) is used as an active energy ray-curable coating is reduced. And the scratch resistance of the coating after curing tends to be poor. On the other hand, when the weight average molecular weight exceeds 200,000, the compatibility with other resin compositions (active energy ray-curable resin oligomers, etc.) is lowered, and the viscosity is increased, so that an appropriate coating viscosity can be obtained with an organic solvent. When diluted, the solid content is remarkably lowered and the paintability tends to be lowered.

  Moreover, it is preferable that the glass transition temperature of this epoxy group containing copolymer (c) is 50-130 degreeC, and it is more preferable that it is 60-110 degreeC. Here, when the glass transition temperature of the epoxy group-containing copolymer (c) is less than 50 ° C., the non-adhesiveness of the coating film obtained when the acrylic polymer (A) is used as an active energy ray-curable coating material. When the temperature exceeds 130 ° C., the appearance, curability and paintability of the resulting coating film tend to decrease.

  Subsequently, an unsaturated double bond group is introduced into the side chain of the epoxy group-containing copolymer (c) by reacting the epoxy group-containing copolymer (c) with an unsaturated carboxylic acid compound. Combine (A) is obtained.

  In the present invention, as the unsaturated carboxylic acid compound, a short-chain unsaturated carboxylic acid (d1) having a molecular weight of less than 150 (more preferably, a molecular weight of 72 or more and less than 100) and a molecular weight of 150 or more (more preferably a molecular weight of 200 or more and less than 1000). One or more types of each of these long-chain unsaturated carboxylic acids (d2) are used.

  Examples of the short-chain unsaturated carboxylic acid (d1) include (meth) acrylic acid and dimers thereof (Aronix M5600). Examples of the long-chain unsaturated carboxylic acid (d2) include caprolactone-modified (meth) acrylic acid (ω-carboxy-polycaprolactone monoacrylate: Aronix M5300 manufactured by Toagosei Co., Ltd.), hydroxyl group-containing (meth) acrylate and anhydrous Compounds obtained by ring-opening reaction with carboxylic acid (phthalic acid monohydroxyethyl acrylate: Aronix M5400 manufactured by Toagosei Co., Ltd., β-acryloyloxyethyl hydrogen succinate: NK ester A-SA manufactured by Shin-Nakamura Chemical Co., Ltd.) It is done.

  When the epoxy group-containing copolymer (c) and the unsaturated carboxylic acid compound are reacted by an addition reaction, the epoxy group and the unsaturated carboxylic acid compound (short chain unsaturated carboxylic acid) of the epoxy group-containing copolymer (c) The equivalent ratio of the carboxyl group of (d1) and the total amount of carboxyl groups contained in the long-chain unsaturated carboxylic acid (d2) is 1: 0.8 to 1: 1 in terms of molar ratio of carboxyl group to epoxy group. It is preferable to mix | blend so that it may become. When the equivalent ratio of the epoxy group and the carboxyl group is less than 1: 0.8, the curability and the coating film performance tend to generally decrease when the obtained resin is used as an active energy ray curable coating. When exceeding 1.1, the non-adhesiveness of the coating film before hardening at the time of setting it as the said coating material tends to fall. This reaction can be performed by a known method in the presence of a basic catalyst, a phosphorus catalyst, or the like.

  Furthermore, the lower limit of the content of the short-chain unsaturated carboxylic acid (d1) in the total molar amount (d1 + d2) of the unsaturated carboxylic acid compound is preferably 20 mol% or more, and 33 mol% or more. The upper limit is preferably 80 mol% or less, and more preferably 67 mol% or less. On the other hand, the lower limit of the content of the long-chain unsaturated carboxylic acid (d2) is preferably 20 mol% or more, more preferably 33 mol% or more, and the upper limit is 80 mol% or less. Preferably, it is 67 mol% or less. When the content of the short-chain unsaturated carboxylic acid (d1) is less than 20 mol% or the content of the long-chain unsaturated carboxylic acid (d2) exceeds 80 mol%, when the active energy ray-curable coating material is obtained, after curing The chemical resistance of the coating film and the coating film hardness tend to be inferior, which is not preferable. When the content of the short-chain unsaturated carboxylic acid (d1) exceeds 80 mol% or the content of the long-chain unsaturated carboxylic acid (d2) is less than 20 mol%, the active energy ray-curable coating is obtained. , The cured film tends to be inferior in flexibility, which is not preferable.

  In the production method of the present invention, the hydroxyl group contained in the acrylic polymer (A) obtained above further has an isocyanate group having one isocyanato group and one or more polymerizable unsaturated bonds in the molecule. The polymerizable unsaturated compound (e) may be subjected to an addition reaction.

  Examples of the isocyanato group-containing polymerizable unsaturated compound (e) include methacryloyloxyethyl isocyanate (trade name Karenz MOI manufactured by Showa Denko KK) and adducts of 1 mol of 2-hydroxyethyl acrylate and 1 mol of hexamethylene diisocyanate. And an isocyanato group-containing (meth) acrylate compound having one isocyanato group in the molecule, obtained by reacting a (meth) acrylate compound having one hydroxyl group in the molecule with a diisocyanate compound.

  The amount of the isocyanato group-containing polymerizable unsaturated compound (e) is 0.1 equivalent or more and 0.8 equivalent or less with respect to the hydroxyl group contained in the acrylic polymer (A) obtained above. It is preferable to add to 0.2, more preferably 0.7 equivalents or less. When the blending amount of the isocyanato group-containing polymerizable unsaturated compound (e) is less than 0.1 equivalent to the hydroxyl group, the cured coating film when the acrylic polymer (A) is used as an active energy ray-curable coating material The characteristics tend to generally decrease, which is not preferable. On the other hand, when the blending amount of the isocyanate unsaturated group-containing polymerizable unsaturated compound (e) exceeds 0.8 equivalents with respect to the hydroxyl group, the acrylic polymer (A) is cured after being used as an active energy ray-curable coating. The coating film properties such as the coating film appearance tend to be deteriorated, which is not preferable.

  The weight average molecular weight (gel permeation chromatography method, standard polystyrene equivalent value) of the acrylic polymer (A) having a polymerizable unsaturated bond obtained as described above is preferably 50,000 to 500,000. More preferably, it is 80,000-400,000. If the acrylic polymer (A) has a weight average molecular weight of less than 50,000, the non-tackiness of the coating film obtained when the acrylic polymer (A) is used as an active energy ray-curable coating tends to decrease. In addition, the coating film hardness of the cured coating film tends to be inferior. On the other hand, if the weight average molecular weight of the acrylic polymer (A) exceeds 500,000, the compatibility with other resin compositions (such as active energy ray-curable resin oligomers) decreases, and the viscosity increases, so that the organic solvent. When diluted to an appropriate coating viscosity, the solid content is remarkably lowered and the paintability tends to be lowered.

  In addition, the reactive unsaturated double bond group contained in the acrylic polymer (A) is preferably 0.67 mol / kg or more and 1.1 mol / kg or more at the lower limit. The upper limit is preferably 3.3 mol / kg or less, and more preferably 2.2 mol / kg or less. When the reactive unsaturated double bond group contained in the acrylic polymer (A) is less than 0.67 mol / kg, the acrylic polymer (A) is used as an active energy ray-curable coating. It is not preferable because the coating properties such as hardness and solvent resistance of the cured coating tend to be lowered. On the other hand, when the reactive unsaturated double bond group exceeds 3.3 mol / kg, when the acrylic polymer (A) is used as an active energy ray-curable coating, it is compatible with other polymerizable oligomers and the like. , The coating film appearance tends to decrease, and the flexibility after curing tends to decrease.

  The hydroxyl value of the acrylic polymer (A) is preferably 30 or more and 125 or less, and more preferably 50 or more and 100 or less. When the hydroxyl value of the acrylic polymer (A) is less than 30, the compatibility with other resin compositions (such as active energy ray-curable resin oligomers) is decreased, and the coating tends to become cloudy. If it exceeds 125, the water resistance of the clear coating film tends to decrease, which is not preferable.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example and a comparative example, this invention is not limited to this.

<Production of epoxy group-containing copolymer (c)>
The epoxy group-containing copolymers (c) of Examples 1 to 5 and Comparative Examples 1 and 2 were produced according to the formulation shown in Table 1 below. That is, (I) was charged in a reaction vessel and heated to 110 ° C. with stirring in a nitrogen gas atmosphere. At 110 ° C., (II) (mixture of the above polymerizable monomer component and perbutyl O (trade name, t-butylperoxy-2-ethylhexanoate) manufactured by NOF Corporation) as a polymerization initiator over 2 hours And dripped. After completion of dropping, the reaction was further carried out at 110 ° C. for 1 hour, and then (III) was added dropwise over 1 hour. After completion of the dropwise addition, the mixture was heated to 145 ° C. and further reacted for 2 hours. After cooling to 100 ° C. or lower, (IV) was added to synthesize an epoxy group-containing copolymer (c). The characteristics of the epoxy group-containing copolymer (c) obtained in each Example and Comparative Example are shown in Table 1 below. In addition, the compounding quantity in a table | surface is a weight (g) and each characteristic value was evaluated by the method described below.

(Weight average molecular weight)
Measurement was carried out under the following instrument measurement conditions, and a standard polystyrene equivalent molecular weight was determined.
Equipment used: Hitachi L6000 type high performance liquid chromatography column: Gelpacks R400, R450 and R400M (trade name of Hitachi Chemical Co., Ltd.)
Eluent: Tetrahydrofuran Column temperature: 40 ° C
Sample concentration: 0.1 g / 5 ml
Flow rate: 2ml / min
Detector: Hitachi L3350 differential refractometer

(Glass transition temperature (Tg))
It calculated from Tg (document value) of the homopolymer of each component using the following formula.
1 / Tg = Σ (W _i / Tg _i )
W _i : Mass fraction of each component Tg _i : Tg of homopolymer of each component

<Production of acrylic polymer (A) having a polymerizable unsaturated bond>
Acrylic polymer having a polymerizable unsaturated bond by introducing a polymerizable unsaturated bond into the epoxy group-containing copolymers (c) obtained in the above examples and comparative examples according to the formulation shown in Table 2 below. (A) was obtained. That is, (V) was charged in a reaction vessel and heated to 90 ° C. with stirring while blowing air. (VI) was added at 90 ° C. and reacted at 90 ° C. for 1 hour, then heated to 105 ° C. and reacted at 105 ° C. until the acid value of the resin solid content became 8 or less. Thereafter, (VII) was added, and then the temperature was set to 75 ° C. (VIII) (trade name Karenz MOI manufactured by Showa Denko KK; methacryloyloxyethyl isocyanate) was added and reacted at 75 ° C. for 2 hours. Thereafter, the mixture was cooled to 60 ° C. or lower, and (IX) was added to synthesize an acrylic polymer (A) having a polymerizable unsaturated bond. The properties of the acrylic polymer (A) obtained in each example and comparative example are shown in Table 2 below. In addition, the compounding quantity in a table | surface is a weight (g) and each characteristic value was evaluated by the method described below.

(Unsaturated double bond group amount)
Unsaturated carboxylic acid (total number of moles of short-chain unsaturated carboxylic acid (d1) and long-chain unsaturated carboxylic acid (d2)) contained per 1000 g of resin solids, and an isocyanate group-containing polymerizable unsaturated compound (e) The total number of moles was calculated from the blended calculated value.

(Hydroxyl value)
Using the following formula, the solid content hydroxyl value of the resin was calculated by the procedures of (1) to (3).
(1) Calculation of hydroxyl value before addition of isocyanato group-containing compound (OH1)
OH1 = [{(A1 + B1) × C1} + {(A2 + B2) × C2}] / P1
(2) Calculation of equivalent amount of isocyanato group-containing compound relative to hydroxyl group
D2 = (42 × P1 × OH1) / (561 × E)
(3) Calculation of hydroxyl value after addition of isocyanato group-containing compound (OH2)
OH2 = [(OH1 × P1) × {1- (D1 / D2)}] / P2
A1: parts by weight of short chain unsaturated carboxylic acid compound
A2: parts by weight of long-chain unsaturated carboxylic acid compound
B1: parts by weight of an epoxy group-containing compound having the same mole number as A1
B2: parts by weight of an epoxy group-containing compound having the same number of moles as A2
C1: Hydroxyl value of A1 + B1 adduct
C2: Hydroxyl value of A2 + B2 adduct
D1: parts by weight of isocyanato group-containing compound
D2: parts by weight of an isocyanato group-containing compound in an equivalent amount with respect to the hydroxyl group
E: NCO content (%) of isocyanato group-containing compound
P1: parts by weight of the component excluding the isocyanato group-containing compound
P2: Total weight part of all components
OH1: Resin solid content hydroxyl value before addition of isocyanato group-containing compound
OH2: Resin solid content hydroxyl value after addition of isocyanato group-containing compound

(Acid value)
In accordance with JIS K5601-2-1, the sample was titrated with a 0.1N potassium hydroxide solution, and the acid value was calculated according to the following formula.
Acid value = (A × f) / B
A: Potassium hydroxide solution titration (ml)
B: Mass of sample (g)
f: True molar concentration of potassium hydroxide solution

<Evaluation of acrylic polymer (A)>
-Preparation of clear paint Irgacure 184 (Ciba Specialty) as a photopolymerization initiator for 100 g of the solid content weight of the acrylic polymer (A) having a polymerizable unsaturated bond of each of the Examples and Comparative Examples obtained above. -4g of Chemicals Co., Ltd. (solid content weight 100%) was added, toluene was added so that it might become 35% of solid content, and it stirred and mixed, and the active energy ray hardening type clear coating material was produced.

-Preparation of test plate The clear coating was applied to a glass plate and a tin plate (thickness 0.5 mm) with a bar coater # 60 and dried at 80 ° C for 10 minutes. Thereafter, the test plate was irradiated with UV light using an ultraviolet (UV) irradiator UV-8408 (manufactured by Nippon Battery Co., Ltd.) with an integrated light quantity of 2,000 mJ / cm ² to prepare a cured coating film.

  The test plate was evaluated for tackiness, hardness, chemical resistance, and flexibility. Test methods and test results (Table 3) are described below.

(Tack free)
The test plate before UV curing and after curing was dried at 80 ° C. for 10 minutes, and then allowed to stand at 25 ° C. for 5 minutes.
Judgment criteria: Not sticky → ○ (pass) Sticky → × (fail)

(hardness)
Pencil hardness was measured according to JIS K5699-5-4, and if it was HB or more, it was determined as pass (◯), and if it was less than HB, it was determined as reject (x).

(chemical resistance)
After curing, the coating film was rubbed 100 times with gauze containing methyl ethyl ketone, and the coating film appearance was evaluated.
Judgment criteria: No abnormality → ○ (Pass) With coating dissolution → × (Fail)

(Flexibility)
The test plate of the tin plate base material was evaluated using a mandrail having a diameter of 32 mm according to JIS K5600-5-1.
Judgment criteria: No crack → ○ (pass) Crack occurrence → × (fail)

  From Table 3, the coating film formed with the active energy ray-curable clear coating prepared using the acrylic polymer (A) of the example is all of tack-free, hardness, chemical resistance, and flexibility. It can be seen that it is superior to that of the comparative example.

  It will be appreciated by those skilled in the art that the foregoing is a preferred embodiment of the invention and that many changes and modifications can be made without departing from the spirit and scope of the invention.

Claims (3)

Polymerizable unsaturated compound (a) having one or more epoxy groups and one polymerizable unsaturated bond in the molecule, and polymerization having one polymerizable unsaturated bond in the molecule other than the component (a) A short-chain unsaturated carboxylic acid (d1) having a short chain length to bond to a carboxyl group and a molecular weight of less than 150, and an epoxy group-containing copolymer (c) obtained by copolymerization with a polymerizable unsaturated compound (b) An acrylic polymer (A) is synthesized by reacting a long-chain unsaturated carboxylic acid (d2) having a long chain length with a carboxyl group and a molecular weight of 150 or more, and is contained in the acrylic polymer (A). 0.1 to 0.8 equivalent of an isocyanate group-containing polymerizable unsaturated compound (e) having one isocyanato group and at least one polymerizable unsaturated bond in the molecule is added to the hydroxyl group to be added. It is characterized by Rukoto reacted A process for the preparation of the acrylic polymer (A) having a polymerizable unsaturated bond,
When the (a) component and the (b) component are copolymerized, the blending ratio of the (a) component and the (b) component is 10: 90-60: 40,
The weight average molecular weight of the epoxy group-containing copolymer (c) is in the range of 30,000 to 200,000,
The epoxy group-containing copolymer (c) has a glass transition temperature of 50 ° C. or higher and 130 ° C. or lower,
The epoxy group of the epoxy group-containing copolymer (c) when the short chain unsaturated carboxylic acid (d1) and the long chain unsaturated carboxylic acid (d2) are reacted with the epoxy group-containing copolymer (c); The equivalent ratio of the total amount of carboxyl groups contained in the short chain unsaturated carboxylic acid (d1) and the long chain unsaturated carboxylic acid (d2) to the carboxyl group is 1: 0 in terms of molar ratio of the carboxyl group to the epoxy group. .8 to 1: 1.1,
The short-chain unsaturated carboxylic acid (d1) and the long-chain unsaturated carboxylic acid (d2) are blended so as to be 20 mol% or more and 80 mol% or less, respectively, with respect to their total molar amount (d1 + d2).
The weight average molecular weight of the acrylic polymer (A) is in the range of 50,000 to 500,000,
The reactive unsaturated double bond group contained in the acrylic polymer (A) is in the range of 0.67 mol / kg to 3.3 mol / kg,
A method for producing an acrylic polymer (A) having a polymerizable unsaturated bond . Wherein the hydroxyl value of the acrylic polymer (A) is 30 or more 125 or less, the production method of the acrylic polymer having a polymerizable unsaturated bond of claim 1, wherein (A).   The production of an acrylic polymer (A) having a polymerizable unsaturated bond according to claim 1 or 2, wherein the long-chain unsaturated carboxylic acid (d2) contains caprolactone-modified (meth) acrylic acid. Method.