JP2008075048A - Coating composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curable composition containing a polycarbonatediol which is excellent in the balance of properties such as coating film hardness, flexibility, acid resistance, alkali resistance, alcohol resistance, oil resistance and the like, and capable of forming a coating film of soft touch. <P>SOLUTION: This curable composition comprises a polyisocyanate compound (a) having at least two isocyanate groups in one molecule, a specific aliphatic polycarbonatediol (b) synthesized from 1,4-butanediol and 1,6-hexanediol, and polyurethane particles (c) having a mean particle diameter of 2-20 μm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polyisocyanate compound having at least two isocyanate groups in one molecule, a polycarbonate diol having at least two hydroxyl groups in one molecule represented by a specific structural formula, and a specific The present invention relates to a curable coating composition comprising polyurethane particles having an average particle diameter of

  Conventionally, polyurethane resins have been used in a wide range of areas such as synthetic leather, artificial leather, adhesives, furniture paints, and automobile paints, and polyethers and polyesters have been used as polyol components to react with isocyanates ( Patent References 1-2). However, in recent years, there has been an increase in demand for resin resistance, such as heat resistance, weather resistance, hydrolysis resistance, weather resistance, and oil resistance, and there has been an increasing demand for soft-feel paints with a soft hand feeling. ing. In general, in order to improve the resistance, it is common to introduce a crosslinked structure into the polymer. However, by this means, the coating film of the paint becomes hard, so that a high level of requirements regarding resistance and a soft feel are required. It was difficult to achieve both.

JP 2000-95836 A JP 2001-123112 A

  The present invention provides a curable coating composition that has an excellent balance of physical properties such as coating film hardness, flexibility, acid resistance, alkali resistance, alcohol resistance, and oil resistance, and that can form a coating film with a soft touch feeling. The purpose is to do.

As a result of intensive studies, the present inventors have found that a desired object can be achieved by combining a polyisocyanate curing agent, a polycarbonate diol having a specific structure, and polyurethane particles having a specific average particle diameter. It came to an eggplant.
That is, the present invention
1. A coating composition comprising the following (a), (b) and (c) as essential components:
(A) A polyisocyanate compound having at least two or more isocyanate groups in one molecule.
(B) It consists of repeating units of the following formulas (1) and (2), and the ratio of the repeating units of the following (1) and (2) is (1) / (2) = 90/10 to 40/60 (molar ratio). An aliphatic polycarbonate diol characterized in that the terminal group is a hydroxyl group.

(C) Polyurethane particles having an average particle diameter of 2 to 20 μm: 3 to 30% by weight as an addition amount in the total solid content,
2. 1. The polyisocyanate compound has at least 2.5 or more isocyanate groups in one molecule. The coating composition according to the description,
3. 1. 0 to 90% by weight of an inert organic solvent is contained. Or 2. The coating composition as described.

  According to the present invention, a coating film having a good balance of physical properties such as coating film hardness, flexibility, acid resistance, alkali resistance, alcohol resistance, oil resistance, and the like can be formed into a soft feel paint with a soft hand feeling. A curable coating composition can be provided.

Hereinafter, the present invention will be described in detail. Polyisocyanate compounds having at least two or more isocyanate groups in one molecule used in the present invention include tolylene diisocyanate, diphenylmethane diisocyanate, diisocyanate cyclohexane, tridendiisocyanate, hexamethylene diisocyanate. Narate, trimethylhexane diisocyanate, 1.5-naphthalene diisocyanate, xylylene diisocyanate, 2.6-diisocyanate methylcaproate, isophorone diisocyanate (IPDI), methylcyclohexane-2,4 (or 2,6) -diisocyanates, 4,4'methylenebis (cyclohexyl isocyanate) and other aromatic, aliphatic, alicyclic isocyanates, or isocyanates derived from these isocyanates alone or in mixtures Low molecular weight having functional groups that react with rate-type polyisocyanates, burette-type isocyanates and these diisocyanates and ethylene glycol, polyether polyols (polyethylene glycol, polypropylene glycol, etc.), caprolactone polyols, polycarbonate polyols and isocyanate groups Lanthanum type adducts with polyester resins (including oil-modified types) and acrylic copolymers, or molar adducts such as 2-hydroxypropyl (meth) acrylate and hexamethylene diisocyanate, isocyanate ethyl (meth) Examples thereof include a copolymer having an isocyanate group containing a vinyl monomer having an isocyanate group and a copolymerizable unsaturated group such as acrylate as an essential component. In particular, from the viewpoint of weather resistance, polyisocyanates derived from aliphatic alicyclic diisocyanates such as hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI) are desirable. Further, these polyisocyanates are blocked with known blocking agents such as lower alcohols such as butanol and 2-ethylhexanol, methyl ethyl ketone oximes, lactams, phenols, imidazoles, and active methylene compounds. An isocyanate curing agent can be used. Examples of these polyisocyanate compounds include Sumidur 44S and 44V70 (all manufactured by Sumika Bayer Urethane), Dismodule HL (manufactured by Sumika Bayer Urethane), which is a copolymer of TDI and HDI, and various duranates manufactured by Asahi Kasei Chemicals. That is, Duranate 24A-100, Duranate 22A-75PX, Duranate 18H-70B, Duranate 21S-75E, Duranate THA-100, Duranate TPA-100, Duranate MFA-75X, Duranate TSA-100, Duranate TSS-100, Duranate TSE-100 , Duranate D-101, Duranate D-201, Duranate P-301-75E, Duranate E-402-90T, Duranate E-402-90T, Duranet E-405-80T, Duranate ME20-100, Duranate 17B-60PX, Duranate TPA-B80X, Duranate MF-B60X, Duranate E-402-B80T, Duranate ME20-B80S, Duranate WB40-100, Duranate WB40-80D, Duranate Available as WT20-100, Duranate WT30-100, etc. In order to improve the acid resistance, alkali resistance, alcohol resistance, oil resistance, abrasion resistance and scratch resistance of the cured coating film, the polyisocyanate compound contains at least 2.5 or more isocyanate per molecule. And / or a blocked isocyanate group, specifically, diisocyanate derivatives such as biuret, allophanate, uretidinedione, isocyanurate, and polyhydric alcohol adducts are more preferable.

  Next, the polycarbonate diol used in the present invention comprises repeating units of the following formulas (1) and (2), and the ratio of the repeating units of the following formulas (1) and (2) is (1) / (2) = 90. / 10 to 40/60 (molar ratio), and an aliphatic polycarbonate diol characterized in that a terminal group is a hydroxyl group.

  As a result of examining various polycarbonate diols for this application, the present inventors have found that a soft feel paint having a soft hand feeling can be obtained by using the carbonate diol having the above specific structure. The polycarbonate diol of the present invention can be obtained from 1,4-butanediol and 1,6-hexanediol by various methods described in Schell, Polymer Review Vol. 9, pages 9-20 (1964). It is a copolymerized polycarbonate diol to be synthesized. When the ratio of the repeating units of the above formulas (1) and (2) constituting the polycarbonate diol exceeds (1) / (2) = 90/10 (molar ratio), the softness of the resulting coating film Is unfavorable because it is damaged. Moreover, the coating film software obtained even when the ratio of the repeating units of the above formulas (1) and (2), which are the repeating units constituting the polycarbonate diol, is less than (1) / (2) = 40/60 (molar ratio) Not only the feeling is impaired, but also the oil resistance and wear resistance are deteriorated, which is not preferable. The ratio of the above formulas (1) and (2), which are repeating units constituting a more preferable polycarbonate diol, is (1) / (2) = 85/15 to 50/50 (molar ratio), more preferably (1) / (2) = 80/20 to 60/40 (molar ratio).

The polycarbonate diol used in the present invention is a copolymerized polycarbonate diol synthesized from 1,4-butanediol and 1,6-hexanediol, but other low molecular weight diols are copolymerized as long as the characteristics are not impaired. It can be contained as a component. Other diols that can be specifically used include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,5-pentanediol, -Methyl-1,3-propanediol, neopentyl glycol, 2,3-butanediol, 2,5-hexanediol, 1,7-heptanediol, 1,8-octanediol, 2-methyl-1,8-octane Examples include diol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and the like. The ratio of these diols is the total amount of 1,4-butanediol and 1,6-hexanediol. As a percentage of merging all, less than 40 wt%, preferably less than 20 wt%, more preferably less than 10 wt%.

In the present invention, the number average molecular weight of the polycarbonate diol is 500 to 10,000, preferably 1000 to 5,000. More preferably, the number average molecular weight is 1500 to 3000. When the number average molecular weight is less than 500, the flexibility of the coating film is lowered and the soft feeling may be significantly impaired. In addition, when the number average molecular weight exceeds 10,000, the reaction with the isocyanate is remarkably slow, and not only does it take a long time to dry, but also the viscosity of the resulting coating composition becomes high and actual coating becomes difficult, which is preferable. Absent.
It is desirable that the polymer ends of the polycarbonate diol used in the present invention are substantially all hydroxyl groups.

In the present invention, 1,4-butanediol, 1,6-hexanediol, and other compounds having three or more hydroxyl groups per molecule, such as trimethylolethane, trimethylolpropane, hexanetriol, pentaerythritol By using a small amount of these, a polyfunctionalized polycarbonate having an average number of hydroxyl groups in one molecule of less than 2.5, preferably less than 2.4 is also included. In the case of polycarbonate polyfunctionalized to 2.5 or more, the viscosity of the resulting coating composition is increased, and not only the actual coating becomes difficult, but also the resulting coating film becomes hard and soft feeling is impaired, which is not preferable. .
The blending ratio of the polycarbonate diol and the polyisocyanate is OH / NCO = 1 / 0.5 to 1 / 1.5 (equivalent ratio), more preferably OH / NCO = 1/0. It is preferable to blend so as to be 8 to 1 / 1.2 (equivalent ratio). If the NCO is less than 0.5 equivalent with respect to 1 equivalent of OH, the predetermined coating film properties cannot be obtained.

  In the present invention, polyurethane particles are used in order to further enhance the soft feeling of the obtained coating film. As the polyurethane particles, a method in which a polyurethane prepolymer is dispersed in water in the presence of a suspension stabilizer and then polymerized, washed and dried (JP-A-1-185648), in the presence of an emulsifier. Spherical polyurethane particles synthesized by a method of emulsion polymerization of polyurethane in a non-aqueous inert liquid (JP-A-5-214054 and JP-A-7-97425). In the synthesis of this polyurethane particle, when a difunctional or lower isocyanate urethane prepolymer is used, a thermoplastic urethane particle is obtained, and when a terminal isocyanate urethane prepolymer exceeding 2 functions is used, a three-dimensionally crosslinked urethane particle is obtained. . The polyurethane particles used in the present invention include three-dimensional cross-linking in order to improve the acid resistance, alkali resistance, alcohol resistance, oil resistance, heat resistance, and wear resistance of the coating film obtained by the present coating composition. The urethane particles used are more preferably used. The average particle diameter of the polyurethane particles used is 2 to 20 μm. If the average particle diameter is less than 2 μm, the resulting coating film has high gloss, and not only does not give a high-quality feeling, but also the soft feeling is lowered. On the other hand, if the average particle diameter exceeds 20 μm, the wear properties of the resulting coating film are lowered and the softness of the surface is impaired, which is not preferable. A more preferable average particle diameter is 4 to 15 μm, and further preferably 5 to 10 μm.

The addition amount of the polyurethane particles in the coating composition part is 3 to 30% by weight of the total solid content contained in the coating composition. When the content of polyurethane particles is less than 3% by weight, the softness of the resulting coating film cannot be obtained, and when the content of polyurethane particles exceeds 30% by weight, the wear properties of the resulting coating film are extremely deteriorated. Therefore, it is not preferable. The amount of polyurethane particles added is preferably 5 to 20%, more preferably 8 to 15% by weight.
The curable coating composition of the present invention includes a curing accelerator (catalyst), a filler, a flame retardant, a dye, an organic or inorganic pigment, a release agent, a fluidity modifier, a plasticizer, and an antioxidant according to various uses. An agent, an ultraviolet absorber, a light stabilizer, an antifoaming agent, a leveling agent, a colorant, a solvent and the like can be added.

Curing accelerators include monoamine triethylamine, N, N-dimethylcyclohexylamine, diamine tetramethylethylenediamine, other triamines, cyclic amines, alcohol amines such as dimethylethanolamine, ether amines, and metal catalysts such as potassium acetate. Potassium 2-ethylhexanoate, calcium acetate, lead octylate, dibutyltin dilaurate, tin octylate, bismuth neodecanoate, bismuth oxycarbonate, bismuth 2-ethylhexanoate, zinc octylate, zinc neodecanoate, phosphine, Commonly used materials such as phospholine can be used.
As fillers and pigments, woven fabric, glass fiber, carbon fiber, polyamide fiber, mica, kaolin, bentonite, metal powder, azo pigment, carbon black, clay, silica, talc, gypsum, alumina white, barium carbonate, etc. Can be used.
As the mold release agent, fluidity adjusting agent, and leveling agent, silicone, aerosil, wax, stearate, polysiloxane such as BYK-331 (manufactured by BYK Chemical Co., Ltd.) and the like are used.

  As the additive used in the present invention, at least an antioxidant, a light stabilizer and a heat stabilizer are preferably used. These antioxidants include phosphoric acid, phosphorous acid, aliphatic, aromatic or alkyl group-substituted aromatic esters and hypophosphorous acid derivatives, phenylphosphonic acid, phenylphosphinic acid, diphenylphosphonic acid, polyphosphonates, dialkylpentaerythritol diesters. Phosphites, phosphorous compounds such as dialkyl bisphenol A diphosphites; phenol derivatives, especially hindered phenol compounds, thioethers, dithioates, mercaptobenzimidazoles, thiocarbanilides, thiodipropionates, and other sulfur-containing compounds; Tin compounds such as dibutyltin monoxide can be used.

These may be used alone or in combination of two or more.
The coating composition of the present invention may contain 0 to 90% by weight of an inert organic solvent as necessary in order to adjust the workability during coating. The inert organic solvent used is an organic solvent which is substantially inert to the polyisocyanate compound and does not have active hydrogen. Examples include hydrocarbons such as pentane, hexane, heptane, octane, decane, petroleum ether, petroleum benzine, ligroin, petroleum spirit, cyclohexane, methylcyclohexane, trichlorofluoroethane, tetrachlorodifluoroethane, perfluoroether, etc. Fluorinated inert liquids such as fluorinated oils, perfluorocyclohexane, perfluorobutyltetrahydrofuran, perfluorodecalin, perfluoro-n-butylamine, perfluoropolyether, dimethylpolysiloxane and the like may be used alone or as a mixture. Furthermore, solvents such as methyl ethyl ketone, acetone, ethyl acetate, butyl acetate, toluene, xylene and the like can be mentioned.

As a coating method of this composition, after mixing each component just before coating, the method of apply | coating to a base material with a spray, a roll, a brush etc. is used. It is also possible to apply a method in which components other than the component (a), which is a curing agent, are mixed in advance, and the component (a) is added and mixed uniformly immediately before application, and then applied.
The curable coating composition of the present invention can be preferably used as a soft feel coating for home appliances, OA products, automobile interior parts, leather surface treatment, synthetic leather surface treatment, and the like.

EXAMPLES Hereinafter, although this invention is demonstrated further in detail using an Example etc., this invention is not limited at all by these examples. In the following Examples and Comparative Examples, various polyols and various physical properties of the polyurethane film were tested according to the following test methods.
<Test method>
1. Insoluble fraction The coating solution was applied onto a glass plate and heated at 80 ° C. for 2 hours to produce a film having a thickness of 40 μm. The film was peeled off from the glass plate, cut to about 3 cm × 3 cm, and then weighed before dipping. Thereafter, the film was put into a copper net and immersed in MEK for 24 hours. The film was taken out from the copper net, dried by heating, weighed after immersion, and the insoluble fraction was calculated from the following equation.
Insoluble fraction [%] = 100 × (film weight after immersion) / (film weight before immersion)

2. Coating film hardness The film on the glass plate formed in the above was measured with a pen drum type hardness meter. The coating sample applied on the glass plate was placed in the apparatus, and the time from when the amplitude reached 5 ° until the amplitude reached 2 ° was measured (t). The same measurement was performed on the uncoated glass plate, and the time from when the amplitude reached 5 ° to when the amplitude reached 2 ° was measured (t0). The hardness (X) was calculated by the following formula.
Hardness: X = t / t0
3. Abrasion resistance The film on the glass plate formed in the above was measured using a Taber type abrasion tester according to the method of JIS K5600-5-8. The weight before the abrasion test and the change in the weight of the coated film after the abrasion test (500 rotations) were measured and expressed.

4). Glossiness With respect to the film on the glass plate formed in step 1, the glossiness of the coating film surface at 85 ° was measured according to the method of JIS K5600-4-7.
5. Soft feeling The soft feeling of the film on the glass plate formed in the above was evaluated by the touch when the film surface was touched by hand. Judgment results were expressed in the following notation.
○: Good soft feeling Δ: Relatively good soft feeling ×: It is not felt soft.

[Example 1]
200 g of polycarbonate diol-1 (PCDL-1: polycarbonate diol obtained by copolymerizing 1,4-butanediol and 1,6-hexanediol at a molar ratio of 70/30, number average molecular weight 2000), leveling Agent BYK-331 (BYK Chemical Co., Ltd.) 2.06 g, dibutyltin dilaurate (Air Product) 1.2 g, polyurethane particles (Art Pearl, C-800, average particle system = 6 μm, Negami Kogyo Co., Ltd.) 35 g As a thinner, 356 g of a mixed solvent of xylene / butyl acetate (70/30) was added and stirred to obtain a paint base. To this was added 38.2 g of Duranate TPA-100 (manufactured by Asahi Kasei Chemicals Corporation: hexamethylene diisocyanate-based isocyanurate type curing agent, NCO content = 23.1 wt%) as a curing agent, and a coating solution was prepared. This was coated on an acrylonitrile-butadiene-styrene (ABS) resin plate and then cured by heating at 80 ° C. for 2 hours to obtain a coating film having a film thickness of 30 to 40 μm. The physical properties are shown in Table 1.

[Example 2]
In place of the polycarbonate diol of Example 1, polycarbonate diol-2 (PCDL-2: a polycarbonate diol obtained by copolymerizing 1,4-butanediol and 1,6-hexanediol at a molar ratio of 87/13) A paint was prepared in the same manner as in Example 1 except that the number average molecular weight 2000) was used. The physical properties are shown in Table 1.
Example 3
Instead of the polycarbonate diol of Example 1, polycarbonate diol-3 (PCDL-3: polycarbonate diol obtained by copolymerizing 1,4-butanediol and 1,6-hexanediol at a molar ratio of 70/30) The number average molecular weight 1000) was used, and a paint was prepared in the same manner as in Example 1 except that the amount of Duranate TPA-100 added was 76.4 g. The physical properties are shown in Table 1.

Example 4
Instead of the curing agent of Example 1, Duranate 24A (Asahi Kasei Chemicals Co., Ltd .: hexamethylene diisocyanate burette type curing agent, NCO content = 23.5 wt%) was changed to 37.5 g, and was the same as Example 1. Created a paint. The physical properties are shown in Table 1.
Example 5
A paint was prepared in the same manner as in Example 1 except that DIAPLACOAT, RHU-5070D (manufactured by Dainichi Seika Kogyo Co., Ltd., polyurethane particles, average particle size = 7 μm) was used instead of the polyurethane particles of Example 1. The physical properties are shown in Table 1.
Example 6
A paint was prepared in the same manner as in Example 1 except that Art Pearl, C-400 (manufactured by Negami Kogyo Co., Ltd., polyurethane particles, average particle system = 14 μm) was used instead of the polyurethane particles of Example 1. The physical properties are shown in Table 1.

Example 7
A 2 L autoclave sufficiently substituted with nitrogen gas and dried was charged with 175 g of ADEKA polyether G-700 (manufactured by Asahi Denka Kogyo Co., Ltd., glycerin PO adduct, hydroxyl value 225 mg / KOHg) and 101 g of hexamethylene diisocyanate, and 120 ° C. And stirred for 20 hours. Thereafter, unreacted hexamethylene diisocyanate was removed under reduced pressure, and then toluene was added to obtain a compound (I) having a nonvolatile content of 90%. 970 g of water was charged into a separable flask equipped with a 2 L stirrer, and 30 g of Hemetroze 90SH-100 (manufactured by Shin-Etsu Chemical Co., Ltd .; methylcellulose) was dissolved therein to prepare a dispersion medium. A solution obtained by diluting 250 g of the compound (I) with 87 g of toluene was added to the dispersion medium while stirring at 1000 rpm to prepare a suspension. With continuous stirring, the suspension was heated to 60 ° C., reacted for 1.5 hours, cooled to room temperature, separated into solid and liquid, thoroughly washed with water, dried at 70 ° C. for 20 hours, and an average particle size of 4 μm. Of urethane particles were obtained. A paint was prepared in the same manner as in Example 1 except that the polyurethane particles synthesized by the above method were used instead of the polyurethane particles in Example 1. The physical properties are shown in Table 1.

Example 8
A coating material was prepared in the same manner as in Example 1 except that the amount of polyurethane particles added in Example 1 was 20 g. The physical properties are shown in Table 1.
Example 9
A paint was prepared in the same manner as in Example 1 except that the amount of polyurethane particles added in Example 1 was changed to 55 g. The physical properties are shown in Table 1.

[Comparative Example 1]
Instead of the polycarbonate diol of Example 1, polycarbonate diol-2 (PCDL-3: 1,4-butanediol and 1,6-hexanediol copolymerized at a molar ratio of 30/70 was obtained. A paint was prepared in the same manner as in Example 1 except that the number average molecular weight 2000) was used. The physical properties are shown in Table 2.
[Comparative Example 2]
In place of the polycarbonate diol of Example 1, polycarbonate diol-2 (PCDL-3: 1,4-butanediol and 1,6-hexanediol copolymerized at a molar ratio of 95/5) A paint was prepared in the same manner as in Example 1 except that the number average molecular weight 2000) was used. The physical properties are shown in Table 2.

[Comparative Example 3]
A paint was prepared in the same manner as in Example 1 except that polycaprolactone (PCL-1, Plaxel 220N, number average molecular weight 2000, manufactured by Daicel Chemical Industries) was used in place of the polycarbonate diol of Example 1. The physical properties are shown in Table 2.
[Comparative Example 4]
A paint was prepared in the same manner as in Example 1 except that Art Pearl C-200 (manufactured by Negami Kogyo Co., Ltd., polyurethane particles, average particle size = 30 μm) was used instead of the polyurethane particles of Example 1. The physical properties are shown in Table 2.

[Comparative Example 5]
A coating material was prepared in the same manner as in Example 1 except that acrylic resin particles (Art Pearl, G-800T (manufactured by Negami Industrial Co., Ltd., average particle system = 6 μm)) were used instead of the polyurethane particles of Example 1. Various physical properties are shown in Table 2.
[Comparative Example 6]
A coating material was prepared in the same manner as in Example 1 except that the amount of polyurethane particles added in Example 1 was changed to 5 g. The physical properties are shown in Table 2.
[Comparative Example 7]
A coating material was prepared in the same manner as in Example 1 except that the amount of polyurethane particles added in Example 1 was changed to 130 g. The physical properties are shown in Table 2.

Claims (3)

A coating composition comprising the following (a), (b) and (c) as essential components:
(A) A polyisocyanate compound having at least two or more isocyanate groups in one molecule.
(B) It consists of repeating units of the following formulas (1) and (2), and the ratio of the repeating units of the following (1) and (2) is (1) / (2) = 90/10 to 40/60 (molar ratio). An aliphatic polycarbonate diol characterized in that the terminal group is a hydroxyl group.

(C) Polyurethane particles having an average particle diameter of 2 to 20 μm: 3 to 30% by weight as an addition amount in the total solid content The coating composition according to claim 1, wherein the polyisocyanate compound has at least 2.5 or more isocyanate groups in one molecule. The coating composition according to claim 1, which contains 0 to 90% by weight of an inert organic solvent.