JP2016084432A - Coating composition and car interior component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating composition or the like excellent in contamination resistance to a sunscreen agent and further excellent in tactile (slimy feeling).SOLUTION: Provided is a coating composition comprising an acrylic modified polycarbonate resin obtained by polymerizing polycarbonate polyol with an acryl resin, in which the average molecular weight is 5,000 to 10,000, and also, a hydroxyl value is 80 to 120 mgKOH/g, a polyisocyanate compound having two or more isocyanate groups at the terminals; and urethane resin fine powder. At this time, as the urethane resin fine powder, the spherical one having the average particle diameter of 6 to 10 μm is preferably used.SELECTED DRAWING: None

Description

  The present invention relates to a coating composition and an automobile interior part having a coating film formed on the surface thereof.

  For automotive interior parts (for example, instrument panels, center consoles, door trims, center clusters, switch panels, shift knobs), paint compositions (tactile feeling paint compositions) for the purpose of improving the touch (feeling of touch, sliminess), etc. ) May be formed.

  As such a coating composition, conventionally, a polyester resin or polyether resin blended with isocyanate is used, and this is applied and formed into a film to form a soft coating film. Some have added PTFE or silicone resin for the purpose of balancing the feel and physical properties.

However, these conventional coating compositions based on polyester resins and polyether resins have a problem in resistance to sunscreens. In other words, a sunscreen agent having a UV blocking function may be applied to automobile interior parts for the purpose of preventing deterioration due to strong sunlight. A coating film made of a coating composition is applied by this sunscreen agent. In some cases, it deteriorated. Specifically, peeling, floating, swelling, and softening of the coating film may occur. Further, when a sunscreen agent such as COPATONE (registered trademark) is used in summer or in a hot area, the coating film may be deteriorated due to adhesion to the interior part.
The coating composition is also required to have stain resistance to such sunscreen agents.

  Here, Patent Document 1 discloses a curable resin composition for coating an automobile interior material having excellent contamination resistance.

Patent Document 1 states that “a silicone-modified vinyl polymer (A) having a polysiloxane group, a hydrolyzable silyl group and a hydroxyl group, and a polyisocyanate compound (B),” A curable resin composition in which a silicone-modified vinyl polymer (A) is copolymerized with a monomer containing 10 to 40% by weight of the total amount of a vinyl compound (c) containing a hydroxyl group. The obtained curable resin composition for paints having a glass transition temperature of 30 to 70 ° C. is described.
As a result, “It is possible to obtain an automotive interior coating material excellent in stain resistance”. In addition, as an evaluation method for contamination resistance, a method using beef tallow and hair liquid is described in the examples (paragraph 0049).

JP 2011-16966 A (claim 1, effect of the invention)

  However, the curable resin composition described in Patent Document 1 has not been studied for the purpose of improving the stain resistance with respect to the sunscreen agent or for improving the tactile sensation.

  The present invention has been made in consideration of the above-mentioned matters, and has excellent anti-contamination resistance against sunscreen (hereinafter sometimes referred to as anti-contamination) and excellent touch (smoothness). It aims at providing a composition etc.

  In order to solve the above problems, an acrylic-modified polycarbonate resin having a number average molecular weight of 5000 to 10,000 and a hydroxyl value of 80 to 120 mgKOH / g obtained by polymerizing polycarbonate polyol with an acrylic resin, and two or more isocyanate groups at the terminal It was set as the coating composition containing the polyisocyanate compound which has, and a urethane resin fine powder.

This coating composition has excellent anti-contamination properties against sunscreen agents and excellent touch feeling.
When an acrylic resin (Tg, high crosslink density) was used as the base resin of the coating composition, the stain resistance to the sunscreen was good but the touch was poor. On the other hand, when a polyester resin or a polyether resin is used as the base resin of the coating composition, the tactile sensation is good, but the anti-contamination property against the sunscreen is poor.
Therefore, for the purpose of achieving both stain resistance and tactile sensation with respect to sunscreens, we studied a blend system of acrylic resin and polyester, but this resulted in a non-uniform coating film that could not achieve both stain resistance and tactile sensation. It was.
The applicant of the present application has repeatedly studied to solve such a problem. As a result, it has been found that a coating composition containing a predetermined acrylic-modified polycarbonate resin, a polyisocyanate compound, and a urethane resin fine powder makes it possible to achieve both contamination resistance and tactile sensation. In particular, the tactile sensation is improved synergistically by the combination of the acrylic-modified polycarbonate resin and the urethane resin fine powder.
Here, when the number average molecular weight of the acrylic-modified polycarbonate resin is less than 5000, the stain resistance of the coating is deteriorated, and when the number average molecular weight exceeds 10,000, the physical properties derived from acrylic become strong and the tactile sensation is lowered. On the other hand, when the hydroxyl value of the acrylic-modified polycarbonate resin is less than 80 mgKOH / g, the stain resistance of the coating is deteriorated, and when the hydroxyl value exceeds 120 mgKOH / g, the curing of the coating proceeds rapidly, so that the pot life (use (Time) is shortened (the paint becomes difficult to handle).

  At this time, it is preferable that the urethane resin fine powder has a spherical shape with an average particle diameter of 6 to 10 μm. Here, the spherical shape refers to a shape having an elliptical shape and / or a circular outer periphery, which is different from an indefinite shape.

  This coating composition forms a coating film with improved tactile sensation. When the urethane resin fine powder has an average particle diameter of 6 μm or more, the urethane resin fine powder is difficult to be buried in the coating film, and it becomes difficult to feel a hard tactile sensation derived from the resin. When the urethane resin fine powder has an average particle diameter of 10 μm or less, the urethane resin fine powder appropriately protrudes from the coating surface (does not protrude too much), and the tactile sensation is further improved.

  At this time, the urethane resin fine powder is preferably a coating composition in which a hydrophobic treatment is applied.

  This coating composition forms a coating film with further improved tactile sensation.

  At this time, the weight ratio of the acrylic modified polycarbonate resin to the urethane resin fine powder is 100: 125 to 100: 160, and the weight ratio of the acrylic modified polycarbonate resin to the polyisocyanate compound is 100: 59 to 100: 72. It is also preferable to use a coating composition.

  This coating composition is compatible with a high level of antifouling property and feel against sunscreen agents.

  These coating compositions are suitable for use in automobile interior parts applied to the surface of automobile interior parts. It is preferable to deposit these coating compositions on the surface of automobile interior parts.

  According to the present invention, it is possible to provide a coating composition having excellent anti-contamination properties against sunscreen agents and excellent touch feeling.

Hereinafter, embodiments of the present invention will be described by way of example. The present invention relates to an acrylic-modified polycarbonate resin having a number average molecular weight of 5,000 to 10,000 and a hydroxyl value of 80 to 120 mgKOH / g obtained by polymerizing a polycarbonate polyol with an acrylic resin, and a polyisocyanate compound having two or more isocyanate groups at the terminal. And a urethane resin fine powder.
The present invention is not limited to the following embodiments and examples.

1. Acrylic-modified polycarbonate resin An acrylic-modified polycarbonate resin is obtained by reacting a polycarbonate polyol with an acrylic resin, and has a number average molecular weight of 5,000 to 10,000 and a hydroxyl value of 80 to 120 mgKOH / g.

Here, the number average molecular weight can be determined, for example, by performing gel permeation chromatography and measuring the molecular weight distribution of the base resin. For specific conditions of gel permeation chromatography, reference can be made to, for example, New Experimental Chemistry Course 19, Polymer Chemistry II, p. 533 (edited by Chemical Society of Japan, Maruzen).
The hydroxyl value means a value corresponding to the weight (mg) of KOH required to neutralize 1 g of a sample, and is calculated by the formula (hydroxyl value = 56,100 / molecular weight per hydroxyl group). Can do. For specific conditions for determining the hydroxyl value, for example, a known method such as JIS K1557 can be referred to.

  Specifically, the acrylic modified polycarbonate resin is synthesized by reacting an acrylic ester and a methacrylic ester with a polycarbonate polyol in the presence of a radical reaction initiator. Hereinafter, the polycarbonate polyol, acrylic acid ester, and methacrylic acid ester used for the synthesis of the acrylic modified polycarbonate resin will be described as an example.

(a) Polycarbonate polyol Various types of polycarbonate polyol can be used. For example, ring opening polymerization of ethylene carbonate or phenyl carbonate (polycarbonate monomer) using polyhydric alcohol as an initiator, polyhydric alcohol such as 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, etc. Polycarbonate polyol obtained by copolymerizing a carbonate monomer with each other can be used.

More specifically, examples of the polycarbonate polyol include trade names DURANOL (registered trademark) T-4671, T-4672, T-4691, T-4692, T-5650J, T-5650E, manufactured by Asahi Kasei Chemicals Corporation. T-5651, T-5652, T-6001, T-6002, trade name of Placel CD CD205, CD205PL, CD205HL, CD210, CD210PL, CD210HL, CD220, CD220PL, CD220HL, manufactured by Kuraray Co., Ltd. Product names Kuraray polyol C-1015N, C-1050, C-1065N, C-1090, C-2015N, C-2065N, C-2090, trade names NIPPOLAN 981, 980R, 982R manufactured by Nippon Polyurethane Industry Co., Ltd. Include those that are commercially available, they can be used alone or in combinations of two or more.
The average functional group number of the polycarbonate polyol is preferably 1.5 to 2.5. Moreover, it is preferable that the hydroxyl value of polycarbonate polyol is 50-250 mgKOH / g, and it is preferable that a number average molecular weight is 500-2000.

  As the polycarbonate polyol, it is preferable to use, for example, polycarbonate diols such as trade names Duranol (registered trademark) T-5650J, T-5650E, T-5651, and T-5651 manufactured by Asahi Kasei Chemicals Corporation. As the polycarbonate diol, those having a number average molecular weight of 500 to 2000 (more preferably, a number average molecular weight of 500 to 1000) and a hydroxyl value of 50 to 250 mgKOH / g are preferably used.

(b) Acrylic acid ester Various acrylic acid esters can be used. For example, methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, n-hexyl acrylate, n-heptyl acrylate, n-acrylate Examples include octyl, 2-ethylhexyl acrylate, methoxyethyl acrylate, methoxypropyl acrylate, ethoxyethyl acrylate, and ethoxypropyl acrylate. These monomers may be used alone or in combination of two or more.

(c) Methacrylic acid ester Various methacrylic acid esters can be used. For example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, n-hexyl methacrylate, n-heptyl methacrylate, n-methacrylate Examples include octyl, 2-ethylhexyl methacrylate, methoxyethyl methacrylate, methoxypropyl methacrylate, ethoxyethyl methacrylate, and ethoxypropyl methacrylate. These monomers may be used alone or in combination of two or more. Moreover, you may use together acrylic ester and methacrylic ester.

(d) Polymerization of acrylic-modified polycarbonate resin An acrylic-modified polycarbonate resin can be synthesized by reacting (polymerizing) an acrylic ester and a methacrylic ester with a polycarbonate polyol in the presence of a radical reaction initiator.
This reaction is based on hydrogen abstraction by radical polymerization. As the radical reaction initiator, for example, a peroxide compound or an azo compound can be used. Especially, it is preferable to use the alkyl peroxide compound which is an organic peroxide of a peroxide. For example, 1,1-bis (t-butylperoxy) cyclohexane.

Then, a mixed solution of acrylic acid ester and methacrylic acid ester (basic ratio is 1: 1) is mixed with polycarbonate polyol at a weight ratio of 8: 2 to 4: 6, and then a radical reaction initiator is added. And mix evenly.
A solvent can be used for mixing. Examples of the solvent to be used include hydrocarbon solvents. Specifically, cyclohexane, mineral spirit, or the like can be used, but isobutyl acetate is preferably used from the viewpoint of assisting compatibility of the solution. The addition amount is preferably 60 to 120 parts by weight with respect to 100 parts by weight of the resin solid content.
A radical polymerization initiator can be 0.1 mol or less with respect to 1 mol of polycarbonate polyols. Moreover, it can also be about 2% with respect to the mixed solution of polycarbonate polyol, acrylic acid ester, and methacrylic acid ester.

  The reaction conditions may be a reaction temperature of 95 to 200 ° C., preferably 100 to 160 ° C. under normal pressure. The reaction time can be 120 to 300 minutes. About reaction equipment, the general reaction kiln currently used for the synthesis of the conventional acrylic resin can be used.

  The raw material charge ratio and the like are adjusted so that the acrylic-modified polycarbonate resin has a number average molecular weight of 5,000 to 10,000 and a hydroxyl value of 80 to 120 mgKOH / g.

2, Polyisocyanate compound As the polyisocyanate compound, one having two or more isocyanate groups at the terminal is used. Examples of such polyisocyanate compounds include aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate, alicyclic diisocyanates such as isophorone diisocyanate, tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, and xylylene diisocyanate. Aromatic diisocyanates such as isocyanate and naphthylene diisocyanate, triphenylmethane-4,4'-4 ''-triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene and Mention may be made of polyisocyanates having three or more isocyanate groups, such as 4,4′-dimethyldiphenylmethane-2,2 ′, 5,5′-tetraisocyanate, as well as polyisocyanates having an isocyanurate ring.

3. Urethane resin fine powder As the urethane resin fine powder, it is preferable to use a spherical resin having an average particle diameter of 6 to 10 μm. The tactile sensation is improved by using a spherical urethane resin fine powder. Moreover, when the average particle size is 6 to 10 μm, the tactile sensation is further improved.

  As a method for obtaining such a fine polyurethane resin fine powder, various known means can be used. For example, a method in which an isocyanate group-terminated urethane prepolymer dispersed in water containing a dispersant is reacted with an extender and, if necessary, a reaction terminator and a crosslinking agent, followed by dehydration and drying, or polyol and polyisocyanate are not used. After reacting in an aqueous solvent to obtain a prepolymer solution, the reaction terminator is further reacted in the solvent, the solution is dispersed in water containing a dispersant, and then the solvent is distilled off under reduced pressure to dehydrate. -The method of drying etc. can be used.

Moreover, as the urethane resin fine powder, it is preferable to use one subjected to a hydrophobic treatment. The tactile sensation is further improved by the hydrophobic treatment. This is because wet treatment with the solvent (hydrophobic organic solvent) is improved by the hydrophobic treatment of the powder surface, so that the urethane resin fine powder that is generally oriented (generally aligned) in the coating film is coated with the coating film when dried. This is presumed to be less affected by the solvent that volatilizes and the orientation in the coating film is less likely to be disturbed. In addition, the effect at the time of using the urethane resin fine powder which carried out the hydrophobic process is not limited to the said principle.
As the urethane resin fine powder that has been subjected to hydrophobic treatment, for example, those whose surface is coated with hydrophobic silica can be used, but are not limited thereto.

4). Preparation of coating composition A coating composition is prepared using these acrylic-modified polycarbonate resin, polyisocyanate compound, and urethane resin fine powder.

Various methods can be used for preparing the coating composition. For example, an organic solvent (for example, propylene glycol monomethyl ether acetate) is added to an acrylic-modified polycarbonate resin to obtain a resin solution having a reduced viscosity, and a urethane resin fine powder can be added to the resin solution and uniformly dispersed. As for the urethane resin fine powder, an organic solvent (for example, methyl isobutyl ketone) may be added and uniformly dispersed in the solvent, and this may be added to the resin solution.
In principle, the polyisocyanate compound as a curing agent is added before coating.

  Here, the weight ratio of the acrylic-modified polycarbonate resin and the urethane resin fine powder is preferably 100: 125 to 100: 160. In addition to this, it is preferable to add the polyisocyanate compound so that the weight ratio of the acrylic-modified polycarbonate resin and the polyisocyanate compound is 100: 59 to 100: 72.

5. Application of Coating Composition and Film Formation The obtained coating composition is applied and formed on the surface of an object to be coated such as an automobile interior part. Examples of automobile interior parts to which the coating composition is applied include an instrument panel, a center console, a door trim, a center cluster, a switch panel, and a shift knob.

  There are no particular restrictions on the method of application to automobile interior parts and the like, for example, various known and commonly used methods such as brush coating, dip coating, spray coating, roll coating, bar coating, and air knife coating can be used. Furthermore, these can also be used in combination. After application, the film is formed by drying at room temperature or by heating. At this time, a crosslinking reaction proceeds in the coating film.

  The thickness of the coating composition during film formation is preferably 20 to 40 μm, more preferably 25 to 35 μm. When a spherical urethane resin fine powder having an average particle diameter of 6 to 10 μm is used, the tactile sensation is further improved in the thickness range during the film formation.

  As described above, after applying the coating composition and forming a film, a sunscreen agent may be applied to the surface of the formed coating composition as necessary.

The coating composition of the present invention has excellent anti-contamination properties against sunscreen agents and excellent tactile sensation when deposited.
Hereinafter, the contents of the present invention will be described more specifically with reference to examples.

[Preliminary study 1]
Preliminary study 1 confirms the stain resistance of an acrylic-modified polycarbonate resin to a sunscreen. In addition, since this preliminary study 1 is a preliminary study on the stain resistance, for the sake of convenience, a study in which a urethane resin fine powder was not blended was performed. Therefore, it is displayed as a reference example in Table 1.

  The acrylic-modified polycarbonate resin used in Reference Example 1 has a number average molecular weight of 7000 and a hydroxyl value of 85 to 100 mgKOH / g. This acrylic-modified polycarbonate resin was synthesized by using a polycarbonate diol (Duranol (registered trademark) T-5650J manufactured by Asahi Kasei Chemicals Corporation), an acrylic ester, and a methacrylic ester in a weight ratio of 50:25:25. It is a thing.

  Then, a polyisocyanate compound (Duranate (registered trademark) TPA-100, manufactured by Asahi Kasei Chemicals Corporation) having an NCO value of 23% is blended with this acrylic-modified polycarbonate resin so as to have an equivalent ratio to the hydroxyl value of the acrylic-modified polycarbonate resin. (Equivalent blending), coated on a substrate (PC / ABS polymer alloy) and heated at 80 ° C. for 10 minutes to form a film.

  In Reference Example 2, a polycarbonate diol resin (Duranol (registered trademark) T-5651 manufactured by Asahi Kasei Chemicals Corporation) was used in place of the acrylic-modified polycarbonate resin used in Reference Example 1. In Reference Example 3, an acrylic resin (Aclidick (registered trademark) WCU-777 manufactured by DIC Corporation) was used in place of the acrylic-modified polycarbonate resin used in Reference Example 1, and Reference Example 4 was used as Reference Example 1. In place of the acrylic-modified polycarbonate resin used in the above, a mixed resin of the above polycarbonate diol resin and the above acrylic resin (acrylic resin blending amount 5 wt%: compatibility was poor and 5 wt% or more could not be blended) was used. is there.

Evaluation of stain resistance for sunscreens is as follows. First, the sunscreen agent (Taisho Pharmaceutical Co., Ltd. Copatone (trademark) UV cut milk III) was uniformly apply | coated to the coating-film surface of test object. The coating amount was 0.5 g / 100 cm ² . And the sample which apply | coated the sunscreen was left to stand for 6 hours in an electric furnace (internal temperature 50 degreeC). Then, using a small amount of neutral detergent, thoroughly wash the surface of the coating film, remove the sunscreen, and dry at room temperature (about 23 ° C). Then, the coating film peel test, hardness test, A dry cloth abrasion test was conducted.

The coating film peeling test (peeling) was performed according to the following procedure. From the surface of the coating film treated with the sunscreen agent, an X-shaped cut mark was created with a cutter knife, and then cellophane tape (Nichiban Cello Tape (registered trademark)) was attached to this portion. Next, the adhered cellophane tape was suddenly pulled in the direction perpendicular to the application surface and peeled off from the test surface. And the presence or absence of peeling of a coating film was confirmed visually, and the thing without peeling was set as (circle) evaluation.
The hardness test (hardness) of the coating film was performed according to the following procedure. The core of a pencil (Mitsubishi Pencil Uni) was strongly pressed at a 45 degree angle and slid against the surface of the coating film treated with the sunscreen. And the hardest pencil hardness which the coating film did not scrape was made into the pencil hardness of the coating-film surface. A pencil having a pencil hardness within 2 ranks from the initial hardness was evaluated as “Good”.
The dry cloth abrasion test (abrasion) of the coating film was performed according to the following procedure. The coating film treated with sunscreen was fixed on the Gakushin type friction fastness test stand. Next, the wearer was reciprocated 200 times on the coating film surface with a load of 49 kPa and a stroke of 100 mm. And the abrasion of the coating-film surface was confirmed by visual observation, and the thing in which a substrate exposure is not recognized was made into o evaluation.

  From Preliminary Study 1, it was found that Reference Example 1 using an acrylic-modified polycarbonate resin was excellent in stain resistance as in Reference Example 3 using an acrylic resin. Interestingly, in Reference Example 4 using a blend system of a polycarbonate diol resin and an acrylic resin, there was a problem in contamination resistance, but in Reference Example 1 using an acrylic modified polycarbonate resin, the contamination resistance was improved. That is, it was found that the contamination resistance is unexpectedly improved by polymerizing these resins rather than blending the polycarbonate diol resin and the acrylic resin.

[Preliminary study 2]
This preliminary study 2 examined the influence of the molecular weight and hydroxyl value of the acrylic-modified polycarbonate resin on the stain resistance. In this preliminary study 2 as well, for the sake of convenience, a system in which no urethane resin fine powder was blended was examined. Therefore, it is displayed as a reference example also in Table 2.

The acrylic modified polycarbonate resin is synthesized using the same raw materials (polycarbonate diol, acrylic acid ester, methacrylic acid ester) as in Reference Example 1, but the levels of these charging ratios are varied to change the hydroxyl value and molecular weight. I prepared something.
The kind of the polyisocyanate compound, the blending amount thereof (blending so as to have an equivalent ratio to the hydroxyl value), the drying conditions, the method for evaluating the stain resistance, and the like are the same as in the preliminary study 1.

  Preliminary study 2 revealed that the stain resistance can be satisfied when the acrylic-modified polycarbonate resin has a number average molecular weight of 5000 to 10,000 and a hydroxyl value of 80 to 120 mgKOH / g.

[Examination study 1]
First, tactile sensation was evaluated for a system in which a predetermined amount of urethane resin fine powder was blended. As the urethane resin fine powder, a spherical resin having an average particle diameter of 6 to 10 μm was used. The surface of the urethane resin fine powder is subjected to a hydrophobic treatment.

Example 1 uses an acrylic-modified polycarbonate resin. This acrylic-modified polycarbonate resin is the same as in Reference Example 1, and has a number average molecular weight of 7000 and a hydroxyl value of 85 to 100 mgKOH / g.
Then, 80 parts by weight of propylene glycol monomethyl ether acetate is added to 100 parts by weight of the acrylic-modified polycarbonate resin to obtain a resin solution. In this resin solution, 10 parts by weight of methyl isobutyl ketone is added to 100 parts by weight of the urethane resin fine powder. A powder dispersion solution with a predetermined amount added was mixed and stirred to obtain a main agent. At this time, the powder dispersion solution was added so that the urethane resin fine powder was 150 parts by weight with respect to 100 parts by weight of the acrylic-modified polycarbonate resin.
A polyisocyanate compound as a curing agent was blended with the main agent immediately before coating to obtain a coating composition. The polyisocyanate compound was blended in an amount equivalent to the hydroxyl value of the acrylic-modified polycarbonate resin (equal blend).

  Comparative Example 1 uses a polycarbonate diol resin (Duranol (registered trademark) T-5651 manufactured by Asahi Kasei Chemicals Corporation), and Comparative Example 2 uses an acrylic resin (Aclidick (registered trademark) WCU-777 manufactured by DIC Corporation). Yes, the procedure for preparing the coating composition is the same as in Example 1.

S wet value was used for evaluation of tactile sensation. The S moisture value is a numerical value of the wet and dry feeling of the coating film (references K. Kawazu, K. Koike, M. Imada and K. Yasuda: SAE Technical Paper Series, 1362 (2000-01)).
Specifically, the evaluation was performed according to the following procedure. First, the coating composition was applied to a flat substrate (PC / ABS polymer alloy), and this was heated and dried (at 80 ° C. for 10 minutes) to prepare a coated plate (coating film). And after leaving this coating plate (coating film) in a constant temperature room at 23 ° C. for 48 hours, using a friction tester (product number KES-SE manufactured by Kato Tech Co., Ltd.), the friction coefficient μ of the coating film and the friction coefficient average deviation μMD Was measured. S wet value (Moist-dry feel) was computed from Formula (1) using the obtained measured value. The target value of the S moisture value is 0.8 or more.

  Example 1 using an acrylic modified polycarbonate resin showed an excellent S moisture value equivalent to Comparative Example 1 using a polycarbonate diol resin alone. On the other hand, in Comparative Example 2 using an acrylic resin, it became clear that the S moisture value was extremely low and the tactile sensation was very poor.

  Here, the S moisture value was also confirmed for Examples 1 (acrylic modified polycarbonate resin) and Comparative Example 2 (acrylic resin) to which no urethane resin fine powder was added, both of which were very low values (minus). It became. On the other hand, when Example 1 to which urethane resin fine powder was added and Comparative Example 2 were compared, there was a marked difference in the S moisture value between them, and therefore a combination of acrylic modified polycarbonate resin and urethane resin fine powder (Example 1) revealed that the S wet value was synergistically improved.

  In Comparative Example 1 (polycarbonate diol resin), in which the urethane resin fine powder was not added, the adhesive strength was high and the tack was too strong, which sometimes made measurement difficult.

  In addition, when the case of using a urethane resin powder that has not been subjected to a hydrophobic treatment was examined, there was a tendency for the S moisture value to be lower and the tactile sensation to be worse than when using a hydrophobic treated powder.

[Examination study 2]
Next, the influence of the amount of the urethane resin fine powder and the polyisocyanate compound on the S moisture value was examined.

The acrylic-modified polycarbonate resin is the same as that used in Example 1 (number average molecular weight is 7000, hydroxyl value is 85 to 100 mgKOH / g). Urethane resin fine powder and polyisocyanate were also used in Example 1. The procedure for preparing the coating composition (excluding the blending amount of the polyisocyanate compound) and the method for evaluating the S moisture value are the same as in Implementation Study 1, and the stain resistance is the same as in Preliminary Studies 1 and 2.
In consideration of the required specifications, the case where the S moisture value was 0.08 or more was evaluated as ○, and the case where it was less than 0.08 was evaluated as ×.

  When the weight ratio of the acrylic modified polycarbonate resin and the urethane resin fine powder is 100: 125 to 100: 160 and the weight ratio of the acrylic modified polycarbonate resin and the polyisocyanate compound is 100: 59 to 100: 72, S Both the moisture value and the stain resistance were judged as ○.

  The present invention has been described above with reference to specific embodiments and examples. However, the present invention is not limited to the above-described embodiments, and is attached to the application for this application by those skilled in the art. Various changes and modifications can be made without departing from the scope of the appended claims.

Claims (6)

An acrylic modified polycarbonate resin having a number average molecular weight of 5,000 to 10,000 and a hydroxyl value of 80 to 120 mgKOH / g obtained by polymerizing a polycarbonate polyol with an acrylic resin;
A polyisocyanate compound having two or more isocyanate groups at its end;
Urethane resin fine powder,
including,
Paint composition.
Urethane resin fine powder
A spherical shape with an average particle diameter of 6 to 10 μm.
The coating composition according to claim 1.
Hydrophobic resin fine powder has been subjected to hydrophobic treatment,
The coating composition according to claim 1 or 2.
The weight ratio of acrylic modified polycarbonate resin and urethane resin fine powder is
100: 125 to 100: 160,
The weight ratio of the acrylic modified polycarbonate resin and the polyisocyanate compound is
100: 59 to 100: 72,
The coating composition according to any one of claims 1 to 3.
The coating composition is
For automotive interior parts applied to the surface of automotive interior parts,
The coating composition according to any one of claims 1 to 4.
  An automotive interior part having the coating composition according to any one of claims 1 to 5 formed on a surface thereof.