JP2012121984A - Coating resin composition excellent in scratch resistance - Google Patents

Abstract

Disclosed is a coating having excellent so-called scratch resistance, which has both flexibility and toughness and excellent adhesion to a base material, and is capable of preventing the coating film from being damaged by self-healing even if the coating film surface is damaged. To provide a resin composition.
A polyisocyanate compound (A) having an isocyanate group equivalent in the range of 290 to 500 g / eq, an average Tg of −9 to 40 ° C., and 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 between them [number of moles of isocyanate groups in the polyisocyanate compound] / [in the polyester polyol (B) [Mole number of hydroxyl group] is contained in a ratio such that it is in the range of 0.75 to 1.5.
[Selection figure] None

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, although a coating film obtained from such a coating composition is excellent in flexibility, a polyester polyol having a relatively low molecular weight and a small number of average functional groups per molecule is used, so that the crosslinking density is sufficiently low. It did not show toughness, and scratch resistance was not sufficient.

JP-A 63-86762

  Therefore, the problem to be solved by the present invention is a coating excellent in so-called scratch resistance, which has both flexibility and toughness, and prevents the coating film from being damaged by self-healing even if the coating film surface is damaged. The object is to provide a resin composition.

  As a result of intensive studies to solve the above problems, the present inventors have obtained an adduct-type polyisocyanate compound obtained by reacting an aliphatic diisocyanate monomer and a polyol, and a nurate obtained by nurating an aliphatic diisocyanate monomer. A polyisocyanate compound selected from the group consisting of type polyisocyanate compounds, wherein the isocyanate group equivalent is in the range of 290 to 500 g / eq, and the average Tg is in the range of -9 to 40 ° C. By using a resin composition containing, as an essential component, a polyester polyol having an average functional group number 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, Combines flexibility and toughness for scratch resistance and substrate adhesion The coating is formed, it found that it is possible to solve the above problem, thereby completing the present invention.

  That is, the present invention is from the group consisting of an adduct type polyisocyanate compound (a1) obtained by reacting an aliphatic diisocyanate monomer and a polyol, and a nurate type polyisocyanate compound (a2) obtained by nurating an aliphatic diisocyanate monomer. Polyisocyanate compound (A) having an isocyanate group equivalent in the range of 290 to 500 g / eq, an average Tg of −9 to 40 ° C., and an average functionality of hydroxyl groups per molecule. The polyester polyol (B) having a group number of 4 to 20 and a number average molecular weight (Mn) in the range of 1000 to 3000 is a ratio of the two [the number of moles of isocyanate groups in the polyisocyanate compound] / [polyester. The number of moles of hydroxyl groups in the polyol (B)] is 0. Relates to a coating resin composition characterized by containing in a ratio such that the range of 75 to 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 polyisocyanate compound (A) used in the present invention is characterized in that its isocyanate group equivalent is in the range of 290 to 500 g / eq. When the isocyanate group equivalent is less than 290 g / eq, the coating film becomes hard and brittle, and the external force cannot be absorbed and the scratch resistance is lowered. When the isocyanate group equivalent exceeds 500 g / eq, the cured coating film becomes too soft and sufficient toughness of the coating film cannot be obtained. Among these, it is more preferable that the isocyanate group equivalent is in the range of 300 to 450 g / eq in terms of further improving the scratch resistance of the coating film.

  The average number of functional groups of isocyanate groups per molecule of the polyisocyanate compound (A) is in the range of 1.5 to 5 in that the crosslink density of the coating film is in a suitable state and the balance between toughness and flexibility is excellent. It is preferable that it is in the range of 2-4.

  In addition, the number average molecular weight (Mn) of the polyisocyanate compound (A) is preferably in the range of 500 to 2000 and in the range of 600 to 1500 in terms of a good balance between 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) includes an adduct-type polyisocyanate compound (a1) obtained by reacting an aliphatic diisocyanate monomer and a polyol, and a nurate-type polyisocyanate compound (a2) obtained by nurating an aliphatic diisocyanate monomer. And a polyisocyanate compound selected from the group consisting of: By using aliphatic diisocyanate as a raw material for the polyisocyanate compound (A), a coating film that is not hard and brittle and has excellent flexibility can be obtained.

  Examples of the diisocyanate monomer used in the production of the adduct type polyisocyanate compound (a1) and the nurate type polyisocyanate compound (a2) include butane-1,4-diisocyanate, hexamethylene diisocyanate, and 2,2,4-trimethylhexamethylene. Examples include diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and xylylene diisocyanate. These may be used alone or in combination of two or more.

  Among the above aliphatic diisocyanate monomers, linear aliphatic diisocyanate monomers such as butane-1,4 diisocyanate and hexamethylene diisocyanate are preferable, and hexamethylene diisocyanate is preferable in that the coating film has a better balance between flexibility and toughness. Is particularly preferred.

  The adduct type polyisocyanate compound (a1) can be obtained by reacting an aliphatic diisocyanate monomer with a polyol. The reaction can be carried out within a temperature range of 20 to 120 ° C. under solvent-free conditions or in various organic solvents that are non-reactive with isocyanate groups and hydroxyl groups, such as toluene and xylene. Moreover, various urethanization catalysts can be used as needed.

  The polyol used in the production of the adduct polyisocyanate (a1) 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 and neopentyl glycol;

  Diols containing ether bonds such as diethylene glycol and dipropylene glycol;

  Alicyclic diols such as 1,4-cyclohexanedimethanol and hydrogenated bisphenol A;

  A diol having an ester group such as hydroxypivalylhydroxypivalate;

  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 polyester diols obtained by polycondensation reaction of the various diols with various lactones such as ε-caprolactone, δ-valerolactone, and 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 polyols may be used alone or in combination of two or more.

  Among the above polyols, the adduct type polyisocyanate compound (a1) obtained is obtained by copolymerization of a polyol containing a diol and a polyvalent carboxylic acid in that it is easy to adjust the isocyanate equivalent of 290 to 500 g / eq. Polyester polyols are preferred. Among them, the polyol is preferably an aliphatic polyol such as 1,3-butanediol, trimethylolpropane, and 2,2,4-trimethyl-1,3-pentanediol, and the polyvalent carboxylic acid is succinic acid or adipic acid. Aliphatic dicarboxylic acids such as azelaic acid and sebacic acid are preferred.

  The urethanization catalyst used in the production of the adduct type polyisocyanate (a1) is cobalt naphthenate, zinc naphthenate, stannous chloride, stannic chloride, tetra-n-butyltin, tri-n-butyltin acetate, Examples thereof include n-butyltin 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.

Next, the nurate type polyisocyanate compound (a2) is obtained by nurating an aliphatic diisocyanate monomer. Here, specifically, the following two methods are mentioned as the method of nurateization.
Method 1-1: A method of obtaining a polyisocyanate compound having an isocyanurate ring structure by nucleating an aliphatic diisocyanate monomer.
Method 1-2: A method of obtaining a polyisocyanate compound having an isocyanurate ring structure by subjecting a polyisocyanate compound obtained by urethanation of an aliphatic diisocyanate monomer and a polyol to a uretation reaction.

  The isocyanuration reaction of the method 1-1 or 1-2 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.

  The polyol used when obtaining polyisocyanate by the said method 1-2 includes the said various polyols. Among these, a diol compound is preferable because an isocyanate group equivalent of the obtained nurate type polyisocyanate compound (a2) can be easily adjusted to a range of 290 to 500 g / eq, and an aliphatic diol is particularly preferable.

  In the above methods 1-1 and 1-2, a monoalcohol and a diol may be added as necessary when nurating to partially urethanate the isocyanate group. Monoalcohol and diol 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. An aliphatic diol having 2 to 10 carbon atoms, such as butanediol and 2,2,4-trimethyl-1,5-pentanediol, and an aliphatic diol having 20 to 40 carbon atoms It is preferable to use together.

  Examples of the uretating catalyst used in the above method 1-1 or 1-1 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) is more preferably an adduct-type polyisocyanate compound (a1) in terms of providing a coating film with a better balance between flexibility and toughness, and in particular, 1,6-diisocyanatohexane, polyols and many An adduct type polyisocyanate compound (a1) obtained by reacting with a polyester polyol obtained by copolymerization with a polyvalent carboxylic acid is preferred.

  The polyester polyol (B) used in the present invention has an average Tg in the range of -9 ° C to 40 ° C. When average Tg is less than -9 degreeC, since the coating film obtained is too soft, scratch resistance falls. Moreover, when average Tg exceeds 40 degreeC, since the coating film obtained is too hard, external force cannot be absorbed and scratch resistance falls. Especially, the range of -8 degreeC-35 degreeC is more preferable at the point which a coating film is excellent in the balance of toughness and a softness | flexibility, and the range of -8 degreeC--20 degreeC is still more preferable.

  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 1500-2700 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 preferred value of the average hydroxyl value of the polyester polyol (B) is in the range of 50 to 350, more preferably in the range of 100 to 300. 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 obtained, for example, by reacting a raw material containing a polyhydric alcohol and a polycarboxylic acid. The raw material may contain fats and oils, fatty acids and the like in addition to the polyhydric alcohol and polyhydric carboxylic acid.

  Examples of the polyhydric alcohol used as the raw material for 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.

  The polyvalent carboxylic acid used as a raw material for the polyester polyol (B) is an aliphatic dicarboxylic acid such as malonic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid; phthalic acid, phthalic anhydride, 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, maleic acid, maleic anhydride, fumaric acid, citraconic acid, Aliphatic unsaturated dicarboxylic acids such as itaconic acid and glutaconic acid; 1,2,5-hexanetricarboxylic acid, trimellitic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 2, And various tricarboxylic acids such as 5,7-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 in that it is easy to design various characteristic values of the obtained polyester polyol (B) to the above-described preferable values. More preferably, the carboxylic acid is adipic acid and sebacic acid, and the aromatic carboxylic acid is phthalic acid, phthalic anhydride, isophthalic acid terephthalic acid, and trimellitic acid.

  Examples of the fats and oils used as a raw material for the polyester polyol (B) include linseed oil, soybean oil, drill oil, tall oil, coconut oil, safflower oil, castor oil, and the like. Among these, coconut oil or castor oil is preferable because it is easy to design various characteristic values of the obtained polyester polyol (B) to the above-described preferable values.

  Examples of the fatty acid used as a raw material for the polyester polyol (B) include simple fatty acids such as hexanoic acid, heptanoic acid, octanoic acid, octenoic acid, nonanoic acid, nonenoic acid, isononanoic acid, decanoic acid, and dodecanoic acid; Examples include mixed fatty acids such as soybean fatty acid, rice bran fatty acid, linseed fatty acid, castor fatty acid and the like. These may be used alone or in combination of two or more. Among these, the mixed fatty acid is preferable and the rice bran fatty acid is more preferable in that it is easy to design various characteristic values of the obtained polyester polyol (B) to the above-described preferable values.

  The polyester polyol (B) is, for example, modified by copolycondensation of the above various raw material components or the polyester polyol obtained by constricting the various raw material components with various polyisocyanates or polyepoxy compounds. It can be obtained by the method of making it. The co-condensation reaction is performed within a temperature range of 150 to 250 ° C. while sequentially removing generated water. Various esterification catalysts may be used as necessary.

  In order to obtain the polyester polyol (B) in which the average Tg is in the range of −9 to 40 ° C. and the average number of functional groups of hydroxyl groups per molecule is in the range of 4 to 20 using the various raw materials, 3 to It is preferable to use a raw material containing a hexafunctional aliphatic polyol and a dicarboxylic acid. Furthermore, it is preferable to use in the range from which the ratio of the 3-6 functional aliphatic polyol component with respect to the gross mass of a reaction raw material will be 15-50 mass%. 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 (A-1) 460 parts by mass of 1,3-butanediol and 659 parts by mass of adipic acid in a four-necked flask equipped with a stirrer, a thermometer, a rectification column, and a nitrogen introduction tube And 43 parts by mass of trimethylolpropane (hereinafter abbreviated as TMP) are 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-1) 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 Example 2: Synthesis of polyisocyanate (A-2) 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. Next, 116 parts by mass of Sobamol 908 (Cognis high-purity dimer alcohol, C ₃₆ H ₇₂ O ₂ , Mw: 536, hydroxyl value: 190 to 220 mg KOH / g) and 11 parts by mass of 1,3-butanediol were added. 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-2) having an average number of functional groups per molecule: 2.0 and an isocyanate group equivalent: 305 g / eq. It was.

Comparative Synthesis Example 1: Synthesis of polyisocyanate compound (A-3) 1000 parts by mass of hexamethylene diisocyanate was charged into a four-necked flask equipped with a stirrer, a thermometer, a rectification column, and a nitrogen introduction tube, and the mixture was placed under a nitrogen stream. Agitation was 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), average functional group number per molecule: 3.7, isocyanate group equivalent: 200 g / eq HDI-based nurate polyisocyanate compound (A-3) Got.

Comparative Synthesis Example 2: Synthesis of polyisocyanate compound (A-4) 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 the nitrogen was streamed. Agitation was 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-4) which is 251 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 3: Synthesis of polyester polyol (B-1) 99 parts by mass of neopentyl glycol and 288 parts by mass of trimethylolpropane in a four-necked flask equipped with a stirrer, a thermometer, a condenser tube, and a nitrogen introduction tube Stirring was started under a nitrogen stream. While checking the state in the flask and controlling the number of revolutions, the temperature was raised to 140 ° C. and after confirming that the flask was uniform, 137 parts by weight of fumaric acid and 176 parts by weight of phthalic anhydride were charged. The temperature was raised to 230 ° C. over time, and the reaction was continued at the same temperature until the acid value became 6 or less. Next, the internal temperature was lowered to 140 ° C., and the nonvolatile content was diluted to 60% with a mixed solvent of xylene / methyl ethyl ketone: 1/1 (weight ratio) to obtain a solution of polyester polyol (B-1).

Synthesis Example 4: Synthesis of polyester polyol (B-2) A four-necked flask equipped with a stirrer, a thermometer, a condenser tube, and a nitrogen inlet tube was 229 parts by weight of palm oil, 64 parts by weight of glycerin, and pentaerythritol. Is added in an amount of 71 parts by mass and 34 parts by mass of ethylene glycol, stirring is started in a nitrogen stream, the temperature is raised to 230 ° C. over 2 hours, and further reacted at the same temperature for 2 hours, and then the temperature is lowered to 140 ° C. Next, 298 parts by mass of phthalic anhydride was charged, the temperature was raised to 230 ° C. over 2 hours, the reaction was continued until the acid value was 6 or less at the same temperature, the temperature was lowered to 140 ° C., and xylene / methyl ethyl ketone: 1 The non-volatile content was diluted to 60% with a mixed solvent consisting of 1/1 (weight ratio) to obtain a solution of polyester polyol (B-2).

Synthesis Example 5: Synthesis of Polyester Polyol (B-3) Polymerization was conducted in the same manner as in Synthesis Example 4 except that the raw materials shown in Table 1 were used instead of the respective raw materials in Synthesis Example 4, and polyester polyol (B -3) solution was obtained.

Synthesis Example 6: Synthesis of Polyester Polyol (B-4) 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 respective raw materials of Synthesis Example 3, and polyester polyol (B -4) was obtained.

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 2 were used instead of the 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) A four-necked flask equipped with a stirrer, a thermometer, a rectifying column, and a nitrogen inlet tube was 281 parts by mass of 1,6-hexanediol and 45 parts by mass of glycerin. Part, diethylene glycol 56 parts by mass, heated to 140 ° C. under a nitrogen stream, confirmed that the system was uniform, and charged with a mixture of 400 parts by mass of adipic acid and 18 parts by mass of phthalic anhydride. . 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 ° C., the mixture was diluted with a mixed solvent containing xylene and methyl isobutyl ketone at a mass ratio of 1/1 until the non-volatile content became 80% to obtain a solution of polyester polyol (B-7).

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 K 5400.

[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 3.

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 3. . The evaluation results are shown in Table 3.

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 4, creating a cured coating film on the glass plate and ABS plate, evaluated. The evaluation results are shown in Table 4.

Claims (5)

A polyadduct selected from the group consisting of an adduct-type polyisocyanate compound (a1) obtained by reacting an aliphatic diisocyanate monomer and a polyol, and a nurate-type polyisocyanate compound (a2) obtained by nurating an aliphatic diisocyanate monomer. Polyisocyanate compound (A) having an isocyanate group equivalent in the range of 290 to 500 g / eq, an average Tg of −9 to 40 ° C., and an average number of functional groups of hydroxyl groups per molecule of 4 to 4. Polyester polyol (B) having a number average molecular weight (Mn) in the range of 1000 to 3000 and a ratio of both [number of moles of isocyanate groups in the polyisocyanate compound] / [polyester polyol (B) The number of moles of hydroxyl groups] is 0.75 to 1. The coating resin composition characterized by containing in a ratio such that the ranges. The coating resin composition according to claim 1, wherein the diisocyanate monomer is 1,6-diisocyanatohexane. The coating resin composition according to claim 1, wherein the polyester polyol (B) is obtained by reacting a raw material containing a 3-6 functional aliphatic polyol and a dicarboxylic acid. The coating resin composition of Claim 3 which contains the said 3-6 functional aliphatic polyol in the ratio of 15-50 mass% in the raw material of the said polyester polyol (B). The coating film obtained by hardening the coating resin composition as described in any one of Claims 1-4.