JP2012087183A - Coating resin composition excellent in scratch resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating resin composition excellent in scratch resistance having softness and toughness, and excellent in base material adhesiveness, wherein a coating film is prevented from being damaged by self-reparing even though a coating film surface is damaged.SOLUTION: The coating resin composition contains a polyisocianate compound (A) in which an isocianate equivalent is in the range of 100 to 280 g/eq and polyesterpolyol (B) in which an average Tg is -50 to -10°C, the number of an average functional group of hydroxyl groups per one molecule is 4 to 20, and a number average molecular weight (Mn) is 1,000 to 3,000 in such the ratio that the ratio of the both ([a molecular number of isocianate groups in the polyisocianate compound]/[a molecular number of hydroxyl groups in the polyesterpolyol (B)]) is in the range of 0.75 to 1.5.

Description

  The present invention relates to a coating resin composition that has excellent scratch resistance and substrate adhesion because a cured coating film has both flexibility and toughness.

  Mobile phone housing, PC housing, plastic products such as audio equipment, electronic material parts such as touch panels and LCD screens, home appliances such as refrigerators, microwave ovens and washing machines, woodworking products such as furniture, golf clubs, tennis rackets, etc. There are many products that require surface scratch resistance, such as sports equipment, architectural interiors such as floors, sinks and doorknobs, and interior and exterior of automobiles.

  As a method for imparting scratch resistance to the surface of these products, a technique for imparting scratch resistance by forming a high-hardness coating film made of a UV curable paint, an EB curable paint, or the like on the surface is known. However, in this method, the use of hard monomers to increase the hardness and the increase in strain at the time of curing shrinkage by increasing the crosslink density reduces the adhesion to the material, causing peeling and cracking in the coating film There was a problem that it was easy to do. Moreover, when these high-hardness coating films were formed on the surface of a plastic film or sheet, secondary processing was very difficult because the coating films were too hard and brittle.

  On the other hand, a method of imparting scratch resistance by using a two-component curable polyurethane-based paint to form a coating film having self-healing performance is known. Specifically, polyester polyol having an average of 2.5 to 3.5 hydroxyl groups per molecule and a number average molecular weight of 500 to 1500, a polyisocyanate and a tin-based urethanization catalyst are essential components. A technique for improving the scratch resistance of a coating film using a coating composition is known (see Patent Document 1). However, since the coating film obtained from such a coating composition uses a polyester polyol having a relatively low molecular weight and a small number of average functional groups per molecule, the crosslinking density is low and sufficient toughness is exhibited. In other words, scratch resistance and substrate adhesion were not sufficient. As other two-component curable polyurethane-based paints, a polyisocyanate component having an average equivalent molecular weight of 120 to 240 g / eq, a diol component having an average equivalent molecular weight of 1000 to 2000 g / eq, and an average equivalent molecular weight of 100 to A technique is known in which scratch resistance is improved using a reactive curable composition containing 500 g / eq of a triol component (see Patent Document 2). However, the coating film obtained from such a reaction curable composition is excellent in flexibility because it contains a high molecular weight diol component, but does not provide toughness, and scratch resistance and substrate adhesion are not sufficient. There wasn't.

JP-A 63-86762 Japanese Patent No. 2707579

  Therefore, the problem to be solved by the present invention is to have both flexibility and toughness, excellent substrate adhesion, and prevent the coating film from being damaged by self-healing even if the coating film surface is scratched. Another object is to provide a coating resin composition excellent in so-called scratch resistance.

  As a result of intensive studies to solve the above problems, the inventors of the present invention have a polyisocyanate compound having an isocyanate group equivalent in the range of 100 to 280 g / eq, and an average Tg in the range of −50 to −10 ° C., By using a resin composition containing as an essential component a polyester polyol having an average number of functional groups of hydroxyl groups per molecule in the range of 4 to 20 and a number average molecular weight (Mn) in the range of 1000 to 3000. It has been found that a coating film having both flexibility and toughness and excellent in scratch resistance and substrate adhesion can be formed and the above-mentioned problems can be solved, and the present invention has been completed.

  That is, in the present invention, the polyisocyanate compound (A) having an isocyanate group equivalent in the range of 100 to 280 g / eq, the average Tg is −50 to −10 ° C., and the average number of functional groups of hydroxyl groups per molecule is 4 to 20 And the polyester polyol (B) having a number average molecular weight (Mn) in the range of 1000 to 3000, the ratio between them [number of moles of isocyanate groups in the polyisocyanate compound] / [in the polyester polyol (B) It is related with the coating resin composition characterized by containing in the ratio which is the range of 0.75-1.5.

  The present invention further relates to a coating film obtained by curing the coating resin composition.

  According to the present invention, as compared with the conventional coating resin composition, it has both flexibility and toughness, excellent substrate adhesion, and self-healing even if the coating surface is scratched. It is possible to provide a coating resin composition excellent in so-called scratch resistance, which is prevented from being scratched, and a cured coating film thereof.

  The isocyanate group equivalent of the polyisocyanate compound (A) used in the present invention is in the range of 100 to 280 g / eq. When the isocyanate group equivalent is less than 100 g / eq, the coating film becomes hard and brittle, and the external force cannot be absorbed, resulting in reduced scratch resistance. When the isocyanate group equivalent exceeds 280 g / eq, the cured coating film becomes too soft and sufficient toughness of the coating film cannot be obtained. Among these, the isocyanate group equivalent is more preferably in the range of 150 to 280 g / eq, and still more preferably in the range of 180 to 260 g / eq, in that the scratch resistance of the coating film is further improved.

  The average number of functional groups of isocyanate groups per molecule of the polyisocyanate compound (A) is in the range of 2 to 5 in that the crosslinking density of the coating film is in a suitable state and the balance between toughness and flexibility is excellent. Is preferable, and the range of 3 to 5 is more preferable.

  In addition, the number average molecular weight (Mn) of the polyisocyanate compound (A) is preferably in the range of 500 to 1500 and preferably in the range of 700 to 1000 in terms of a good balance between the toughness and flexibility of the coating film. Is more preferable.

In the present invention, the number average molecular weight (Mn) of the polyisocyanate compound (A) is a value measured by gel permeation chromatography (GPC) under the following conditions.
Measuring device: HLC-8220 manufactured by Tosoh Corporation
Column: Guard column H _XL- H manufactured by Tosoh Corporation
+ Tosoh Corporation TSKgel G5000H _XL
+ Tosoh Corporation TSKgel G4000H _XL
+ Tosoh Corporation TSKgel G3000H _XL
+ Tosoh Corporation TSKgel G2000H _XL
Detector: RI (differential refractometer)
Data processing: Tosoh Corporation SC-8010
Measurement conditions: Column temperature 40 ° C
Solvent tetrahydrofuran
Flow rate 1.0 ml / min Standard; polystyrene sample; 0.4% by weight tetrahydrofuran solution in terms of resin solid content filtered through a microfilter (100 μl)

  The polyisocyanate compound (A) may be any polyisocyanate compound such as aliphatic polyisocyanate, alicyclic polyisocyanate, and aromatic polyisocyanate. Specifically, butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, xylylene diisocyanate, m-tetramethylxylylene diisocyanate Aliphatic diisocyanates such as;

  Cycloaliphatic diisocyanates such as cyclohexane-1,4-diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, methylcyclohexane diisocyanate;

  1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate And various diisocyanate monomers such as aromatic diisocyanates such as 1,4-phenylene diisocyanate and tolylene diisocyanate.

  The polyisocyanate compound (A) is an adduct-type polyisocyanate obtained by reacting, for example, an excess of a diisocyanate monomer and a polyol as a modified polyisocyanate based on the various diisocyanate monomers described above in addition to the various diisocyanate monomers described above. Including a compound (a1), a nurate polyisocyanate compound (a2) having an isocyanurate ring structure in the molecule obtained by polymerizing the above-mentioned various diisocyanate monomers, or a burette bond obtained by reacting with water Polyisocyanate and the like can be mentioned, and these can be used in the same manner as the diisocyanate monomer.

  The adduct type polyisocyanate compound (a1) can be obtained, for example, by the reaction of Method 1-1: isocyanate monomer and polyol. The reaction of Method 1-1 is performed within a temperature range of 20 to 120 ° C. The reaction is carried out in the absence of a solvent, but various organic solvents that are non-reactive with isocyanate groups and hydroxyl groups, such as toluene and xylene, may be used. Moreover, various urethanization catalysts can be used as needed.

  The isocyanate monomer used in the method 1-1 may be any isocyanate monomer such as various isocyanate monomer compounds exemplified as the polyisocyanate compound (A). The isocyanate monomers may be used alone or in combination of two or more.

  The polyol used in Method 1-1 is a compound having two or more hydroxyl groups in the molecule. Specifically, for example, ethylene glycol, propylene glycol, 1,2,2-trimethyl-1,3-propanediol, 2,2-dimethyl-3-isopropyl-1,3-propanediol, 2,2-dimethyl -3-benzyl-1,3-propanediol, 2,2-dimethyl-3-isobutyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,2,3,3 -Tetramethyl-1,4-butanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,2,4-trimethyl-1,5-pentanediol, 1,6-hexanediol, 2, Aliphatic diols such as 4,4-trimethyl-1,6-hexanediol, neopentyl glycol, etc .; A such as diethylene glycol, dipropylene glycol, etc. Diols having a hydrogen bond; Alicyclic diols such as 1,4-cyclohexanedimethanol and hydrogenated bisphenol A; Diols having an aromatic ring such as xylylene glycol and bisphenol A alkylene glycol adduct; Hydroxypivalyl hydroxypivalate, etc. A diol having an ester group of

  Polyether glycols such as polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethylene polyoxytetramethylene glycol, polyoxypropylene polyoxytetramethylene glycol, polyoxyethylene polyoxypropylene polyoxytetramethylene glycol;

  Modified polymers obtained by ring-opening polymerization of the various diols with various cyclic ether bond-containing compounds such as ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, and allyl glycidyl ether. Ether diols;

  The various diols, succinic acid, adipic acid, azelaic acid, sebacic acid, terephthalic acid, isophthalic acid, orthophthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, Polyester diols obtained by cocondensation with oils such as dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, linseed oil, soybean oil, tung oil, tall oil, coconut oil, safflower oil, castor oil;

  Lactone-based polyester dipolyols obtained by polycondensation reaction of the various diols with various lactones such as ε-caprolactone, δ-valerolactone, 3-methyl-δ-valerolactone;

  A lactone-modified polyester diol obtained by a polycondensation reaction between the various diols, the dicarboxylic acid, and the lactone;

  When synthesizing polyester diols such as the lactone polyester diol and lactone modified polyester diol, bisphenol A type epoxy compound, hydrogenated bisphenol A type epoxy compound, glycidyl ether of monoalcohol or diol, or glycidyl of monocarboxylic acid or dicarboxylic acid Epoxy-modified polyester diols obtained by using various epoxy compounds such as esters in combination;

  Polyester polyamide diol, polycarbonate diol, polybutadiene diol, polypentadiene diol, diol having a fluorine atom or a silicon moiety in the molecular structure;

  Aliphatic polyols such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol;

  Obtained by ring-opening polymerization of polyols containing various diols with various cyclic ether bond-containing compounds such as ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, and allyl glycidyl ether. Modified polyether polyols;

  Polyols containing various diols, succinic acid, adipic acid, azelaic acid, sebacic acid, terephthalic acid, isophthalic acid, orthophthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, Dicarboxylic acids such as glutaconic acid and 1,4-cyclohexanedicarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4 -Copolymerization with polyhydric carboxylic acids such as cyclohexatricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, and oils such as linseed oil, soybean oil, drill oil, tall oil, coconut oil, safflower oil, castor oil Polyester polyols obtained by condensation;

  A lactone polyester dipolyol obtained by a polycondensation reaction between the polyol containing the various diols and various lactones such as ε-caprolactone, δ-valerolactone, and 3-methyl-δ-valerolactone;

  A lactone-modified polyester polyol obtained by a polycondensation reaction between the polyol containing the various diols, the dicarboxylic acid, and the lactone;

  When synthesizing polyester diols such as lactone polyester polyols and lactone modified polyester polyols, bisphenol A type epoxy compounds, hydrogenated bisphenol A type epoxy compounds, glycidyl ethers of monoalcohols and diols, or glycidyls of monocarboxylic acids and dicarboxylic acids Epoxy-modified polyester polyols obtained by using various epoxy compounds such as esters;

  Examples thereof include polyester polyamide polyol, polycarbonate polyol, polybutadiene polyol, polypentadiene polyol, and polyol having a fluorine atom or a silicon site in the molecular structure. These hydroxyl group-containing compounds may be used alone or in combination of two or more. Among these, an aliphatic polyol is preferable in that it is easy to adjust the isocyanate equivalent of the obtained adduct type polyisocyanate compound (a1) to 100 to 280 g / eq, and 1,3-butanediol, trimethylolpropane is preferable. And 2,2,4-trimethyl-1,3-pentanediol are more preferred.

  The urethanization catalyst used in Method 1-1 is cobalt naphthenate, zinc naphthenate, stannous chloride, stannic chloride, tetra-n-butyltin, tri-n-butyltin acetate, n-butyltin. Examples include trichloride, trimethyltin hydroxide, dimethyltin dichloride, dibutyltin acetate, dibutyltin dilaurate, and tin octenoate. When using these catalysts, it is preferable to use in the range used as 10-500 ppm with respect to the total mass of a raw material.

The nurate polyisocyanate compound (a2) can be obtained, for example, by the following two methods.
Method 2-1: A method of obtaining a polyisocyanate compound having an isocyanurate ring structure by nucleating a diisocyanate monomer.
Method 2-2: A method of obtaining a polyisocyanate compound having an isocyanurate ring structure by subjecting a polyisocyanate compound obtained by urethanation of a diisocyanate monomer and a polyol to a uretation reaction.

  The isocyanuration reaction of the method 2-1 or 2-2 can be performed within a temperature range of 20 to 120 ° C. The reaction is carried out in the absence of a solvent, but various organic solvents that are non-reactive with isocyanate groups and hydroxyl groups, such as toluene and xylene, may be used. Moreover, you may use various nurating catalysts as needed.

  Examples of the polyol used when obtaining the polyisocyanate by the method 2 include the above-mentioned various polyols. Among these, a diol compound is preferable in that the isocyanate group equivalent of the obtained nurate type polyisocyanate compound (a2) can be easily adjusted to the above preferable value, and an aliphatic diol is particularly preferable.

  The diisocyanate used in the method 2-1 or 2-2 may be any diisocyanate such as various diisocyanate compounds exemplified as the polyisocyanate compound (A). Each of the diisocyanates may be used alone or in combination of two or more.

  In the above methods 2-1 and 2-2, a monoalcohol and a diol may be added as necessary when nurated to partially urethanate the isocyanate group. The alcohols and diols used here are hexanol, 2-ethylhexanol, octanol, n-decanol, n-undecanol, n-dodecanol, n-tridecanol, n-tetradecanol, n-pentadecanol, n-heptadecanol. Nol, n-octadecanol, n-nonadecanol, eicosanol, 5-ethyl-2-nonanol, trimethylnonyl alcohol, 2-hexyldecanol, 3,9-diethyl-6-tridecanol, 2-isoheptylisoundecanol, 2 -Monoalcohols such as octyldodecanol and 2-decyltetradecanol; and the above various diols. These monoalcohols and diols may be used alone or in combination of two or more.

  Among these, a diol compound is preferable in that it is easy to adjust the isocyanate group equivalent of the obtained nurate-type polyisocyanate compound (a2) to the above-described preferable value. Among them, an aliphatic diol is preferable, and 1,3 is particularly preferable. -Butanediol and 2,2,4-trimethyl-1,5-pentanediol are preferred.

  Examples of the nurating catalyst used in the above method 2-1 or 2-1 include quaternary ammonium compounds, specifically 2-hydroxyethyl, trimethylammonium, 2,2-dimethylpropionate, 2- Hydroxyethyl, tri-n-butylammonium, 2,2-dimethylbutanoate, 2-hydroxypropyl, tri-n-butylammonium, 2,2-dimethylpropionate, 2-hydroxypropyl, tri-n-butylammonium, 2 , 2-dimethylbutanoate, 2-hydroxypropyl tri-n-butylammonium 2,2-dimethylpentanoate, 2-hydroxypropyl tri-n-butylammonium 2-ethyl-2-methylpropionate, 2-hydroxypropyl tri-n-butylammonium 2-ethyl-2 Examples include methylbutanoate, 2-hydroxypropyl, tri-n-butylammonium, 2-ethyl-2-methylpentanoate, 2-hydroxypropyl, tri-n-octylammonium, and 2,2-dimethylpropionate. . When using these catalysts, it is preferable to use in the range used as 10-500 ppm with respect to the total mass of a raw material.

  The polyisocyanate compound (A) may be used alone or in combination of two or more. Among these, the adduct-type polyisocyanate compound (a1) and the nurate-type polyisocyanate compound (a2) are preferable in that the coating film has a better balance between flexibility and toughness, and particularly the nurate-type polyisocyanate compound (a2). ) Is more preferable, and in particular, a nurate-type polyisocyanate compound (a2) obtained by nucleating 1,6-diisocyanatohexane is preferable.

  The polyester polyol (B) used in the present invention has an average Tg in the range of −50 ° C. to −10 ° C. When average Tg is less than -50 degreeC, since the coating film obtained is too soft, scratch resistance falls. Moreover, when average Tg exceeds -5 degreeC, since the obtained coating film is too hard, external force cannot be absorbed and scratch resistance falls. Especially, the range of -40 degreeC--15 degreeC is more preferable, and the range of -30 degreeC--15 degreeC is still more preferable at the point which a coating film is excellent in the balance of toughness and a softness | flexibility.

  The average number of functional groups of hydroxyl groups per molecule of the polyester polyol (B) is in the range of 4-20. When the average number of functional groups of the hydroxyl group is less than 4, the crosslinked density of the cured coating film becomes low, so that sufficient toughness cannot be expressed. Moreover, when the average functional group number of a hydroxyl group exceeds 20, since the crosslinked density of a cured coating film is too high, it becomes a hard and brittle coating film and cannot absorb external force, and scratch resistance falls. Especially, the range of 5-15 is more preferable at the point which a coating film is excellent in scratch resistance, and the range of 5-10 is still more preferable.

  The number average molecular weight (Mn) of the polyester polyol (B) is in the range of 1000 to 3000. When the number average molecular weight (Mn) is less than 1000, the coating film is hard and brittle, and sufficient toughness is not exhibited. Moreover, when a number average molecular weight (Mn) exceeds 3000, a coating film is too soft and sufficient scratch resistance is not expressed. Among these, the range of 1200-2500 is preferable at the point with the good balance of the softness | flexibility and toughness of a coating film, and being excellent in scratch resistance.

In the present invention, the number average molecular weight (Mn) of the polyester polyol (B) is a value measured by gel permeation chromatography (GPC) under the following conditions.
Measuring device: HLC-8220 manufactured by Tosoh Corporation
Column: Guard column H _XL- H manufactured by Tosoh Corporation
+ Tosoh Corporation TSKgel G5000H _XL
+ Tosoh Corporation TSKgel G4000H _XL
+ Tosoh Corporation TSKgel G3000H _XL
+ Tosoh Corporation TSKgel G2000H _XL
Detector: RI (differential refractometer)
Data processing: Tosoh Corporation SC-8010
Measurement conditions: Column temperature 40 ° C
Solvent tetrahydrofuran
Flow rate 1.0 ml / min Standard; polystyrene sample; 0.4% by weight tetrahydrofuran solution in terms of resin solid content filtered through a microfilter (100 μl)

  The preferable value of the average hydroxyl value of the polyester polyol (B) is in the range of 50 to 250, more preferably in the range of 100 to 200. When the average hydroxyl value is within the above range, the crosslinked density of the cured coating film becomes a suitable value, and the toughness and scratch resistance of the coating film are combined.

The polyester polyol (B) is, for example,
Method 3-1: A method obtained by co-condensation reaction between a polyhydric alcohol and a polycarboxylic acid,
Method 3-2: It is produced by a method obtained by modifying the polyester polyol obtained in Method 3-1 with various polyisocyanates or polyepoxy compounds. The reaction of the method 3-1 is carried out within the temperature range of 150 to 250 ° C. while sequentially removing the generated water. Various esterification catalysts may be used as necessary.

  Examples of the polyhydric alcohol used in the synthesis of the polyester polyol (B) include the polyols listed in the description of the method 1. These may be used alone or in combination of two or more. Among them, aliphatic polyols are preferable in that it is easy to design various property values of the obtained polyester polyol (B) to the above-described preferable values, and ethylene glycol, 1,3-butanediol, neopentyl glycol, 1 More preferred are diols such as 1,6-hexanediol and 3-6 functional polyols such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and dipentaerythritol.

  Examples of the polyvalent carboxylic acid used in the synthesis of the polyester polyol (B) include aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, and sebacic acid; (anhydrous) phthalic acid, terephthalic acid, Aromatic dicarboxylic acids such as isophthalic acid and orthophthalic acid; Alicyclic dicarboxylic acids such as hexahydrophthalic acid and 1,4-cyclohexanedicarboxylic acid; Tetrahydrophthalic acid, (anhydrous) maleic acid, fumaric acid, citraconic acid, itaconic acid Aliphatic unsaturated dicarboxylic acids such as glutaconic acid; 1,2,5-hexanetricarboxylic acid, trimellitic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5, Examples include various tricarboxylic acids such as 7-naphthalenetricarboxylic acid. These may be used alone or in combination of two or more. Among these, it is preferable to use an aliphatic carboxylic acid and an aromatic carboxylic acid in combination because the various characteristic values of the resulting polyester polyol (B) can be easily designed to the above-described preferable values. As the carboxylic acid, adipic acid and sebacic acid are preferable, and as the aromatic carboxylic acid, phthalic acid, phthalic anhydride, isophthalic acid, and trimellitic acid are more preferable.

  The reaction raw material for producing the polyester polyol (B) in which the average Tg is in the range of −50 to −10 ° C. and the average number of functional groups of hydroxyl groups per molecule is in the range of 4 to 20 is the polyester polyol obtained. The raw material containing a 3-6 functional aliphatic polyol and a dicarboxylic acid, or an aliphatic diol and a trifunctional polycarboxylic acid is included in that it is easy to adjust the Tg and average functional group number of (B) to desired values. A raw material is preferred. Moreover, in the reaction raw material of the polyester polyol (B), the trifunctional or higher functional component such as a tri- or hexafunctional aliphatic polyol or a trifunctional polycarboxylic acid is 10 to 40% by mass of the total mass of the reaction raw material. It is preferable to use within a range. One type of the polyester polyol (B) may be used alone, or a plurality of types synthesized with different compositions may be used in combination.

  The esterification catalyst used in the above methods 3-1 and 3-2 is dibutyltin oxide, antimony trioxide, zinc acetate, zinc acetate, manganese acetate, cobalt acetate, calcium acetate, lead acetate, tetrabutyl titanate, tetraisopropyl titanate, etc. Is mentioned. When using these catalysts, it is preferable to use in the range used as 10-500 ppm with respect to the total mass of a raw material.

  The blending ratio of the polyisocyanate (A) and the polyester polyol (B) in the coating resin composition of the present invention [number of moles of isocyanate groups in the polyisocyanate] / [number of moles of hydroxyl groups in the polyester polyol (B)] is It is a range which becomes the range of 0.75-1.5. By mix | blending with the ratio used as this range, hardening of a coating film advances in a shorter time.

  You may add a hardening accelerator to the coating resin composition of this invention as needed. As the curing accelerator, a urethanization catalyst such as the organotin compound mentioned in the method 1 can be used.

  In addition, a lubricant, an antiblocking agent, an ultraviolet absorber, a light stabilizer, an antistatic agent, an antifogging agent, a colorant, and the like are appropriately added to the coating resin composition part of the present invention as long as the effects of the present invention are not impaired. May be.

  Since the coating film comprising the coating resin composition of the present invention described above has both flexibility and toughness, the coating film absorbs external force and is hardly scratched. Excellent self-healing and scratch resistance. Furthermore, the adhesion to various materials, the secondary workability of the object to be coated, and the coating film appearance are also excellent. Therefore, the coating resin composition of the present invention is used for plastic products such as mobile phone casings, personal computer casings, audio equipment, electronic material parts such as touch panels and liquid crystal screens, household appliances such as refrigerators, microwave ovens and washing machines, and furniture. Such as woodwork products such as golf clubs, sports equipment such as tennis rackets, architectural interiors such as floors, sinks and doorknobs, interior and exterior of automobiles, etc. The coating resin composition of the present invention can also be applied as a plastic film / sheet and used as a laminated film / sheet having scratch resistance.

  The thickness of the coating film when the coating resin composition of the present invention is applied on various substrates can be appropriately adjusted according to the use, but is preferably 1 μm to 100 μm in terms of expressing higher scratch resistance. 5 μm to 50 μm is more preferable.

  Hereinafter, the present invention will be described in more detail with reference to specific synthesis examples and examples.

Synthesis of polyisocyanate compound (A) [Measurement of isocyanate group content]
It measured according to JIS K7301.

[Measurement of number average molecular weight Mn]
It calculated | required on condition of the following using the gel permeation chromatography (GPC).

Measuring device: HLC-8220 manufactured by Tosoh Corporation
Column: Guard column H _XL- H manufactured by Tosoh Corporation
+ Tosoh Corporation TSKgel G5000H _XL
+ Tosoh Corporation TSKgel G4000H _XL
+ Tosoh Corporation TSKgel G3000H _XL
+ Tosoh Corporation TSKgel G2000H _XL
Detector: RI (differential refractometer)
Data processing: Tosoh Corporation SC-8010
Measurement conditions: Column temperature 40 ° C
Solvent tetrahydrofuran
Flow rate 1.0 ml / min Standard; polystyrene sample; 0.4% by weight tetrahydrofuran solution in terms of resin solid content filtered through a microfilter (100 μl)

[Calculation of average number of functional groups per molecule]
It calculated using the following calculation formula from the value of the isocyanate content rate measured by the said method, and the number average molecular weight.
[Average number of functional groups per molecule] = [Number average molecular weight (Mn)] × [Isocyanate content] / 4200

Synthesis Example 1: Synthesis of polyisocyanate compound (A-1) A 4-necked flask equipped with a stirrer, a thermometer, a rectification column, and a nitrogen introduction tube was charged with 1000 parts by mass of hexamethylene diisocyanate and stirred under a nitrogen stream. Started. Next, 20 parts by mass of trimethylpentanediol and 6 parts by mass of 1,3-butanediol were added, and the temperature was raised to 65 ° C. The mixture was reacted at the same temperature for 1 hour, and then 0.1 part by mass of a nurating catalyst (“TOYOCAT TRX” manufactured by Tosoh Corporation) was added and reacted for 15 minutes, and then the refractive index was measured. 0.1 parts by mass of the nurate catalyst was added until the refractive index was 1.4665, and after confirming that the refractive index was 1.4665, phosphoric acid was used as a reaction terminator and the total amount of nurate catalyst added. Of 0.3 parts by mass, which was 1/2 of the above, and stirred for 30 minutes. The internal temperature was raised to 140 ° C., and unreacted hexamethylene diisocyanate was distilled off under reduced pressure at the same temperature. Distillation under reduced pressure at the same temperature is continued until the content of hexamethylene diisocyanate is less than 0.5% by mass relative to the total mass of the reactants in the flask, NCO%: 21.3, Gardner viscosity (25 ° C.): YZ, number average molecular weight (Mn): 720 (GPC measurement), HDI nurate type polyisocyanate compound (A-1) having an average number of functional groups per molecule: 3.7, isocyanate group equivalent: 200 g / eq Got.

Synthesis Example 2: Synthesis of polyisocyanate compound (A-2) 1000 parts by mass of hexamethylene diisocyanate was charged in a four-necked flask equipped with a stirrer, a thermometer, a rectification column, and a nitrogen introduction tube, and stirred under a nitrogen stream. Started. Next, the temperature was raised to 90 ° C., and 90 parts by mass of trimethylolpropane and 16 parts by mass of 1,3-butanediol were dividedly charged over 1 hour while paying attention to heat generation. Furthermore, after reacting at the same temperature for 2 hours, the temperature was raised to 140 ° C., and unreacted hexamethylene diisocyanate was distilled off under reduced pressure at the same temperature. After continuing the vacuum distillation at the same temperature until the hexamethylene diisocyanate content is less than 0.5% with respect to the total mass of the reactants in the flask, the ethyl acetate is adjusted so that the nonvolatile content is 75% by mass. NCO% after dilution: 12.5, Gardner viscosity (25 ° C.): KL, number average molecular weight (Mn): 930 (GPC measurement), average functional group number: 3.7, isocyanate group equivalent: The HDI adduct type polyisocyanate compound (A-2) which is 251 g / eq was obtained.

Comparative Synthesis Example 1: Synthesis of polyisocyanate (A-3) 1000 parts by mass of hexamethylene diisocyanate was charged into a four-necked flask equipped with a stirrer, a thermometer, a rectifying column, and a nitrogen introduction tube, and stirred under a nitrogen stream. Started. Then, 116 parts by mass of Sobamol 908 (Cognis high-purity dimer alcohol, Mw: 536, hydroxyl value: 190 to 220 mg KOH / g) and 11 parts by mass of 1,3-butanediol were added, and the temperature was raised to 75 ° C. . The reaction was carried out at the same temperature for 1 hour, and the refractive index was measured (initial refractive index). Next, 0.1 part by mass of a nurating catalyst (“TOYOCAT TRX” manufactured by Tosoh Corporation) was added and reacted for 15 minutes, and then the refractive index was measured again. The nurating catalyst was added in an amount of 0.1 parts by mass until the refractive index became the initial refractive index plus 0.008. Thereafter, 0.4 parts by mass of phosphoric acid as a reaction terminator, which was ½ of the total amount of the nurating catalyst, was added and stirred for 30 minutes. The internal temperature was raised to 140 ° C., and unreacted hexamethylene diisocyanate was distilled off under reduced pressure at the same temperature. Vacuum distillation at the same temperature is continued until the content of hexamethylene diisocyanate is less than 0.5% by mass with respect to the total mass of the reactants in the flask. NCO%: 14.0, Gardner viscosity (25 ° C.): Z, number average molecular weight (Mn): 610 (GPC measurement), obtaining an HDI nurate polyisocyanate compound (A-3) having an average number of functional groups per molecule: 2.0 and an isocyanate group equivalent: 305 g / eq. It was.

Comparative Synthesis Example 2: Synthesis of polyisocyanate (A-4) 460 parts by mass of 1,3-butanediol and 659 adipic acid in a four-necked flask equipped with a stirrer, a thermometer, a rectification column, and a nitrogen introduction tube Then, 43 parts by mass of trimethylolpropane (hereinafter abbreviated as TMP) is charged, and the temperature is raised to 200 ° C. over 2 hours under a nitrogen stream. Further, the reaction was continued at the same temperature until the acid value became 5 or less to obtain a polyester resin (MA-1) having a hydroxyl value of 125 and a number average molecular weight of 1000.

  A four-necked flask equipped with a stirrer, thermometer, rectification column, and nitrogen inlet tube was charged with 1000 parts by mass of hexamethylene diisocyanate and then 400 parts by mass of polyester resin (MA-1), and stirring was started under a nitrogen stream. did. Then, the temperature was raised to 120 ° C., reacted at the same temperature for 6 hours, and then raised to 140 ° C., and unreacted hexamethylene diisocyanate was distilled off under reduced pressure at the same temperature. After continuing the vacuum distillation at the same temperature until the content of hexamethylene diisocyanate is less than 0.5% with respect to the total mass of the reactants in the flask, NCO%: 10.5, Gardner viscosity (25 ° C): An HDI adduct polyisocyanate compound (A-4) having Z6, number average molecular weight (Mn): 1500 (GPC measurement), average functional group number: 3.5, and isocyanate group equivalent: 429 g / eq was obtained.

Synthesis of polyester polyol (B) [measurement of Tg (glass transition temperature)]
A test sample having a polyester polyol (B) solid content of 100% was prepared and measured using a differential scanning calorimeter ("TOLEDO DSC822e" manufactured by METTLER).

[Measurement of hydroxyl value]
Measured according to JIS K 1557.

[Measurement of number average molecular weight (Mn)]
It calculated | required similarly to the case of polyisocyanate (A).

[Calculation of average number of functional groups per molecule]
It calculated using the following calculation formula from the hydroxyl value and number average molecular weight which were measured with the said method.
[Average number of functional groups per molecule] = [Number average molecular weight (Mn)] × [Hydroxyl value] / 56100

Synthesis Example 5: Synthesis of polyester polyol (B-1) A 4-necked flask equipped with a stirrer, a thermometer, a rectifying column, and a nitrogen introduction tube was charged with 107 parts by mass of ethylene glycol and 180 parts by mass of neopentyl glycol. After raising the temperature to 140 ° C. under a nitrogen stream, the system was confirmed to be uniform, and a mixture of 128 parts by mass of terephthalic acid, 234 parts by mass of sebacic acid, and 101 parts by mass of trimellitic acid was added. The temperature is raised to 230 ° C. over 3 hours, and the reaction is continued at the same temperature until the acid value becomes 5 or less. Subsequently, after cooling to 140 degreeC, it diluted with the mixed solvent containing xylene and methyl isobutyl ketone by mass ratio 1/1 until the non volatile matter became 75%, and the solution of the polyester polyol (B-1) was obtained.

Synthesis Examples 6 to 8: Synthesis of Polyester Polyols (B-2) to (B-4) As in Synthesis Example 3, except that the raw materials shown in Table 1 were used instead of the respective raw materials in Synthesis Example 3 above. Polymerization was performed to obtain solutions of polyester polyols (B-2) to (B-4).

Comparative Synthesis Examples 3 and 4: Synthesis of Polyester Polyols (B-5) and (B-6) Same as Synthesis Example 3 except that the raw materials shown in Table 1 were used instead of the respective raw materials of Synthesis Example 3 above. Polymerization was promoted, and the reaction was continued until the viscosity became XY instead of the acid value to obtain a solution of polyester polyols (B-5) and (B-6).

Comparative Synthesis Example 5: Synthesis of Polyester Polyol (B-7) Polymerization was conducted in the same manner as in Synthesis Example 3 except that the raw materials shown in Table 1 were used in place of the above raw materials. The solution was diluted until the content became 80% to obtain a solution of polyester polyol (B-7).

Comparative production example 1: Production of polyester polyol mixture (B-8) 202 parts by mass of polyol (B-5) having an average equivalent molecular weight of 267 and 608 parts by mass of polyol (B-6) having an average equivalent molecular weight of 100 were mixed to obtain an average equivalent weight. The molecular weight was 140. Next, 90 parts by mass of polycarbonate diol having an average equivalent molecular weight of 1000 and 100 parts of ethyl acetate were mixed to obtain a solution of polyester polyol (B-8) having a nonvolatile content of 90%.

Test coating film preparation method Polyisocyanate (A) and polyester polyol (B), the ratio [number of moles of isocyanate group of polyisocyanate] / [number of moles of hydroxyl group of polyester polyol (B)] is 1 Blended into Next, a catalyst (approximately 50 ppm of dibutyltin acetate) was mixed into the above blend, the viscosity was adjusted with a solvent (ethyl acetate), and coated on various substrates with a 3 mil applicator. After setting at room temperature for 15 minutes, it was dried at 80 ° C. for 1 hour, and further cured at 25 ° C. humidity: 50% for 1 week.

Evaluation method [Pencil hardness test]
The cured coating film coated on the glass plate was evaluated according to JIS K 5400 by a pencil scratch test with a load of 500 g. Test 5 times for each hardness, and apply a hardness one level lower than the hardness at which the coating film breaks even once in 5 times, or the pencil mark does not return even when heated with hot air at 70 ° C. The film hardness was used.

[Pencil mark restoration time]
The time until the pencil mark having the hardness which was the hardness of the coating film was restored in the pencil hardness test was measured and evaluated as follows.
O: No pencil mark A: Restores within 30 minutes after the pencil mark is made.
B: Recover within 30 minutes to 24 hours after the pencil mark.
C: It does not completely recover within 24 hours after the pencil marks, but it recovers when heated with hot air at 70 ° C.

[Adhesion test]
A 100 mm grid of 1 mm × 1 mm was created with a cutter knife on the coating film created on the ABS plate, and “cello tape” manufactured by Nichiban Co., Ltd. was applied, followed by peeling. At this time, the number of grids in which the coating film adhered without peeling was evaluated.

[Glossy]
The gloss value of 60 ° specular reflectance [%] of the coating film prepared on the ABS plate was measured according to JIS-K5400.

[Abrasion resistance]
A disc-shaped indenter having a diameter of 2.4 cm was wrapped with 0.5 g of steel wool (“Bonster # 0000” manufactured by Nippon Steel Wool Co., Ltd.), and was subjected to 10 reciprocating wear at a load of 500 g. Using an automatic haze computer ("HZ-2" manufactured by Suga Test Instruments Co., Ltd.), the haze value of the coating film on the glass plate before abrasion measured in advance and the haze value of the cured coating film after the abrasion test were measured. Measurements were made, and the wear resistance was evaluated based on the difference between them. The smaller the difference value, the better the wear resistance.

Example 1
The polyisocyanate compound (A-1) and the polyester polyol (B-1) are converted into [number of moles of isocyanate group in (A-1)] / [number of moles of hydroxyl group in (B-1)] = 1 /. 1, 84 parts by mass of the polyisocyanate compound (A-1), 200 parts by mass of the polyester polyol (B-1), 30 parts by mass of ethyl acetate, and 0.02 parts by mass of dibutyltin acetate were mixed with stirring to obtain a dry film. After application onto a glass plate and a black acrylonitrile butadiene styrene copolymer resin plate (hereinafter abbreviated as “ABS” plate) using an applicator so that the thickness becomes 40 μm, the coating is dried at a temperature of 80 ° C. for 1 hour, and further 25 It was dried for 1 week under the conditions of ° C. and humidity 60% RH to prepare a cured coating film. About the obtained cured coating film, pencil hardness, adhesion, gloss, and abrasion resistance were evaluated. The evaluation results are shown in Table 2.

Examples 2-4
A cured coating film was prepared and evaluated on a glass plate and an ABS plate in the same manner as in Example 1 except that the types and blending ratios of the polyisocyanate (A) and the polyol (B) were changed as shown in Table 2. . The evaluation results are shown in Table 2.

Comparative Examples 1-5
Compounding in the same manner as in Example 1 except that the types and blending ratios of polyisocyanate (A) and polyol (B) were changed as shown in Table 2, and creating a cured coating film on the glass plate and ABS plate, evaluated. The evaluation results are shown in Table 2. In Comparative Examples 4 and 5, since the coating film was not cured, various coating film evaluations could not be performed.

Claims (7)

A polyisocyanate compound (A) having an isocyanate group equivalent of 100 to 280 g / eq, an average Tg of −50 to −10 ° C., an average number of functional groups of hydroxyl groups per molecule of 4 to 20, and The polyester polyol (B) having a number average molecular weight (Mn) in the range of 1000 to 3000, the ratio of [number of moles of isocyanate groups in the polyisocyanate compound] / [mol of hydroxyl groups in the polyester polyol (B)] The coating resin composition is contained in a ratio such that the [number] is in the range of 0.75 to 1.5. The coating resin composition according to claim 1, wherein the polyisocyanate compound (A) is an adduct type polyisocyanate compound (a1) obtained by reacting a diisocyanate monomer and a polyol. The coating resin composition according to claim 1, wherein the polyisocyanate compound (A) is a nurate-type polyisocyanate compound (a2) obtained by nurating a diisocyanate monomer. The coating resin composition according to claim 2, wherein the diisocyanate monomer is 1,6-diisocyanatohexane. The coating resin composition according to claim 3, wherein the diisocyanate monomer is 1,6-diisocyanatohexane. The polyester polyol (B) is obtained by reacting a raw material containing a 3-6 functional aliphatic polyol and a dicarboxylic acid, or an aliphatic diol and a trifunctional polycarboxylic acid. Coating resin composition. The coating film obtained by hardening the coating resin composition as described in any one of Claims 1-6.