JPH04366189A - Coating composition - Google Patents

Abstract

PURPOSE:To provide a coating composition which is excellent in scratch resistance, staining resistance, water resistance and flexibility, can be applied to various materials such as metals, synthetic resins, wood, glass and concrete and can be used for precoating automobiles, a household appliances, building materials, metals, etc. CONSTITUTION:A coating composition comprising a high-molecular polymer A obtained by reacting a compound B having an isocyanate group and a hydroxyl group and obtained by reacting a diisocyanate compound with a diol compound with an amino-containing high-molecular vinyl polymer and a crosslinking agent, wherein the polymer A contains 10-50wt.% compound B.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a new coating composition, and more particularly to a coating composition that provides a coating film with excellent scratch resistance, stain resistance, etc.

0002

BACKGROUND OF THE INVENTION In order to maintain the initial quality of coated products for a long period of time, it has been desired to develop paints with excellent scratch resistance. For example, top coats applied to automobile exterior panels are susceptible to scratches during car washes, etc.
Since scratches are noticeable in dark-colored paints, which have recently been in increasing demand, there is a desire to develop paints that provide a paint film that is resistant to scratches, and various studies are being carried out.

[0003] As paints with excellent scratch resistance, paints with extremely hard coatings that are difficult to scratch have been proposed;
This paint has the problem of poor impact resistance and processability due to poor flexibility of the coating film, and has not been put into practical use.

[0004]Recently, therefore, paints have been proposed in which the scratch resistance is improved by imparting rubber elasticity to the paint film to absorb external forces that cause scratches. For example, JP-A-64-40573, JP-A-64-43373, JP-A-64-40571, JP-A-64-66.
No. 274 proposes a paint in which a low molecular weight polyester polyol, polyether polyol, polyacrylate polyol, etc. is mixed with a high molecular compound; however, in the paint, it is difficult to crosslink the low molecular weight compound efficiently; Furthermore, these low molecular weight compounds have a problem of poor solvent resistance and water resistance due to weak intermolecular cohesive force.

[0005] Also, in Japanese Patent Application Laid-Open No. 2-222753,
It has been proposed to improve scratch resistance using a polymer to which caprolactone has been added, but since caprolactone itself has a weak cohesive force, it easily swells with organic solvents, etc., resulting in poor stain resistance.

[0006]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a coating composition that provides a coating film with particularly excellent scratch resistance without impairing the flexibility, solvent resistance, water resistance, stain resistance, etc. of the coating film. It's about providing things.

[0007]

[Means for Solving the Problems] According to the present invention, a compound A having an isocyanate group and a hydroxyl group obtained by reacting a diisocyanate compound and a diol compound,
It contains a polymer D obtained by reacting with an amino group-containing vinyl polymer B and a crosslinking agent, and the polymer D contains 10 to 50% by weight of the compound A. A coating composition is provided.

Further, according to the present invention, a vinyl monomer obtained by reacting a compound A having an isocyanate group and a hydroxyl group obtained by reacting a diisocyanate compound and a diol compound with an amino group-containing vinyl monomer. A coating material comprising a polymer E obtained by polymerizing a raw material monomer containing mer C and a crosslinking agent, and wherein the polymer E contains 10 to 50% by weight of the compound A. A composition is provided.

The present invention will be explained in more detail below.

The coating composition of the present invention is characterized by containing a specific high molecular weight polymer D or a specific high molecular weight polymer E and a crosslinking agent.

The specific polymer D used in the present invention is a compound A having an isocyanate group and a hydroxyl group obtained by reacting a diisocyanate compound and a diol compound, and a vinyl polymer B containing an amino group.
(hereinafter simply referred to as polymer B).

In the present invention, the compound A used as a raw material component of the high molecular weight polymer D is a compound obtained by reacting a diisocyanate compound and a diol compound. As the diisocyanate compound used, aliphatic, alicyclic or aromatic diisocyanate compounds can be preferably used. Specifically, as the aliphatic diisocyanate compound, for example, hexamethylene diisocyanate, hexamethylene diisocyanate trimer (isocyanate), etc. Nurate,
biuret, trimethylolpropane adduct type, etc.), ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, lysine diisocyanate, and derivatives thereof; Examples of alicyclic diisocyanate compounds include isophorone diisocyanate, methylcyclohexane-2,4-( or 2,
6-) Diisocyanate, 4,4-methylenebis(cyclohexyl isocyanate), adducts of each of the above diisocyanates and polyhydric alcohols such as ethylene glycol and trimethylolpropane, burettes added with water, polymers of the above diisocyanates, etc. Preferable examples of the aromatic diisocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, and derivatives thereof. Among the above-mentioned diisocyanate compounds, alicyclic diisocyanate compounds are particularly preferably used because they provide a coating film with good weather resistance and the compound synthesis reaction can be easily controlled. Further, when used, they can be used alone or as a mixture.

Further, as the diol compound used as a raw material component of the compound A, specifically, for example, 1,4-
Butanediol, 1,5-pentanediol, 1,6-
Diol compounds having 4 to 10 carbon atoms such as hexanediol and 1,10-decanediol; polycaprolactone diols such as reaction products of ethylene glycol, neopentyl glycol, or the aforementioned diols having 4 to 10 carbon atoms, and ε-caprolactone. ; Preferred examples include polyethylene glycol and the like.

[0014] In order to prepare compound A by reacting the diisocyanate compound and the diol compound, for example,
The diisocyanate compound and the diol compound are charged in equimolar amounts, and the reaction is carried out at a reaction temperature of 10 to 60°C, preferably using an aromatic solvent, an ester solvent, a ketone solvent, etc. as a solvent. can be obtained. Further, it is preferable that the end point of the reaction is set at the time when the concentration of the isocyanate group becomes half, and when the end point is reached, the reaction vessel is rapidly cooled to stop the reaction. In the reaction, a tin-based catalyst such as dibutyltin dilaurylate, an acid-based catalyst such as an organic carboxylic acid, or a basic catalyst such as a tertiary amine may be used as necessary.

The polymer B used as a raw material component of the high molecular weight polymer D may be a homopolymer of an amino group-containing vinyl monomer or a copolymer copolymerized with another vinyl monomer. It can be preferably used. Specifically, the amino group-containing vinyl monomer is, for example, N-
Methylaminoethyl acrylate, N-methylaminoethyl methacrylate, N-ethylaminoethyl acrylate, N-ethylaminoethyl methacrylate, N-propylaminoethyl acrylate, N-propylaminoethyl methacrylate, N-butylaminoethyl acrylate, N-butyl Aminoethyl methacrylate, N-
Preferred examples include butylaminobutyl acrylate, N-butylaminobutyl methacrylate, and monoallylamine. Examples of other vinyl monomers include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, octyl acrylate, octyl methacrylate, dodecyl acrylate, dodecyl methacrylate, octadecyl acrylate, and octadecyl methacrylate. Acrylic monomers containing no functional groups other than saturated double bonds; Acrylic monomers containing carboxyl groups such as acrylic acid and methacrylic acid; 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxy Hydroxyl group-containing acrylic monomer such as propyl methacrylate; hydroxyl group obtained by reacting the hydroxyl group-containing acrylic monomer with caprolactone (for example, product name "Plaxel FM Monomer" manufactured by Daicel Chemical Industries, Ltd.) Containing acrylic monomers: Epoxy group-containing acrylic monomers such as glycidyl acrylate and glycidyl methacrylate; Esters of maleic acid and monohydric alcohol; Vinyl monomers such as styrene, α-methylstyrene, vinyl acetate, and vinyl chloride Polymers and the like can be preferably used.

When a copolymer is used as the polymer B, the blending amount of the amino group-containing vinyl monomer is as follows:
It is preferable to mix the compound A so that the content of the compound A in the high molecular weight polymer D obtained by reacting the compound A with the compound A is 10 to 50% by weight.

The average molecular weight of the polymer B is preferably in the range of 3,000 to 45,000 in terms of weight average molecular weight. When the weight average molecular weight is less than 3000, the weight average molecular weight of the polymer D obtained by reacting with compound A will be less than 5000, and the weather resistance, water resistance, scratch resistance, stain resistance, etc. of the coating film will be reduced. If it exceeds 45,000, the weight average molecular weight of the polymer D will exceed 50,000, resulting in poor coating workability, which is not preferable. The glass transition temperature (Tg) of polymer B is -20 to 60°C.
It is preferable that If the Tg is less than -20°C, the resulting coating film will be too soft, resulting in poor water resistance and stain resistance; if it exceeds 60°C, the resulting coating film will be too hard, resulting in poor scratch resistance and impact resistance. This is not preferable because it lowers the temperature.

To prepare the polymer B used in the present invention, the amino group-containing vinyl monomer and other vinyl monomers are dissolved in an organic solvent and heated in the presence of a radical polymerization initiator. It can be produced by a solution polymerization method by carrying out a polymerization reaction. Examples of organic solvents include aromatic hydrocarbon solvents such as toluene, xylene, and "Solvesso #100" (trade name, manufactured by Exxon Chemical Co., Ltd.); ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate, propylene acetate. Ester solvents such as glycol monomethyl ether; ketone solvents such as methyl isobutyl ketone and methyl amyl ketone; butyl alcohol,
Alcohol solvents such as amyl alcohol; ether alcohol solvents such as ethylene glycol monobutyl ether can be used; and as radical polymerization initiators, benzoyl peroxide, lauroyl peroxide, t-
Butyl peroxybenzoate, azobisisobutyronitrile, etc. can be used.

The high molecular weight polymer D can be produced by reacting the compound A and the polymer B. In the reaction, it is preferable to use an ester solvent, a ketone solvent, an aromatic solvent, etc. as a solvent, and carry out the reaction at a reaction temperature of 10 to 50° C. for 1 to 4 hours. When the reaction temperature is less than 10°C, the reaction takes a long time, and when it exceeds 50°C, a reaction between the hydroxyl group and the isocyanate group in the compound A occurs, which is not preferable.

In the above reaction, the charging ratio of compound A and polymer B is such that the molar ratio of amino group/isocyanate group is 1/
It is preferable that the ratio be in the range of 1 to 1.2/1. If the charging ratio is outside the range, the reaction will proceed unevenly, which is not preferable.

The specific polymer E used in the present invention is obtained by polymerizing a raw material monomer containing a vinyl monomer C obtained by reacting the compound A with an amino group-containing vinyl monomer. It is a thing.

The compound A used as a raw material component for the high molecular weight polymer E is the same as the compound A used for the high molecular weight polymer D, and the amino group-containing vinyl monomer is
This is the same as the amino group-containing vinyl monomer that is the raw material component of the polymer B described above. Further, the raw material monomer may contain a vinyl monomer C obtained by reacting the compound A with an amino group-containing vinyl monomer. At this time, in addition to the vinyl monomer C, other vinyl monomers can also be used. The other vinyl monomers are the same as the vinyl monomers described above.

[0023] The compound A and the amino group-containing vinyl monomer are preferably blended in such a manner that the amino group/isocyanate molar ratio is 1/1 to 1.2/1, and the reaction is The reaction can be carried out in the same manner as the reaction between compound A and polymer B described above. Furthermore, the polymerization reaction for preparing the high molecular weight polymer E can be carried out in the same manner as the polymerization of the polymer B described above.

The weight average molecular weight of the high molecular weight polymer D or high molecular weight polymer E is preferably in the range of 5,000 to 50,000. If the weight average molecular weight is less than 5,000, the weather resistance, water resistance, scratch resistance, stain resistance, etc. of the coating film will be poor, and if it exceeds 50,000, the coating workability will be poor, which is not preferable.

The content of compound A in polymer D or polymer E used in the present invention is in the range of 10 to 50% by weight. If the content is less than 10% by weight, the rubber elasticity of the coating film is too low, resulting in poor scratch resistance.
If it exceeds 50% by weight, the coating film will become too soft, resulting in poor water resistance, stain resistance, coating film hardness, etc.

When an acrylic monomer having a hydroxyl group is used as the vinyl monomer, the crosslinking agent used as an essential component in the present invention is, for example, the diisocyanate compound; Blocked isocyanate compounds such as blocked isocyanate compounds blocked with alcohol or ε-caprolactam; formaldehyde is added to melamine, benzoguanamine, etc., and then the carbon number is 1 to 4.
Amino resins such as resins etherified using monohydric alcohols and the like can be preferably used, and can be used alone or as a mixture. The blending ratio of the polymer D or E and the crosslinking agent is 5 to 70 parts by weight per 100 parts by weight of the polymer D or E. Preferably, 20 to 50 parts by weight is particularly preferred. If the blending ratio of the crosslinking agent is less than 5 parts by weight, the hardness of the coating film will decrease, and if it exceeds 70 parts by weight, the weather resistance and water resistance of the coating film will deteriorate, which is not preferable.

The coating composition containing the high molecular weight polymer D or high molecular weight polymer E of the present invention may optionally contain a solvent, a pigment,
Additives can be added. Further, other resins such as acrylic resins having compatibility may be added within a range that does not adversely affect the effects of the present invention.

[0028]

[Effects of the Invention] The coating composition of the present invention has excellent scratch resistance, as well as stain resistance, water resistance, and flexibility.
It can be applied to various materials such as metals, synthetic resins, wood, glass, and concrete, and can be used for a wide variety of applications such as automobiles, home appliances, building materials, and pre-coating metals.

[0029]

EXAMPLES Next, the present invention will be specifically explained with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited thereto. All parts and percentages hereinafter are based on weight unless otherwise specified.

[0030]

[Synthesis Example 1] (Synthesis of Compound A) Into a flask equipped with a stirrer, a reflux condenser, and a thermometer, the compounds shown in Table 1 were charged in the proportions shown in Table 1, and 50 parts of butyl acetate was charged as a solvent. 60
Compounds A-1 and A-2 were obtained by reacting at °C for 3 hours. The results are shown in Table 1.

[0031]

[Table 1]

[0032]

[Synthesis Example 2] (Synthesis Examples B-1 to B-6 of Polymer B) In a flask equipped with a stirrer, a reflux condenser, and a thermometer, the compounds shown in Table 2 were added in the proportions shown in Table 2. 98 parts of xylene was charged as a solvent, and the temperature was raised to 140°C. Next, at the same temperature, monomers and polymerization initiators were added dropwise at the blending ratios shown in Table 2 over 3 hours. Next, 0.5 part of t-butyl peroxybenzoate was added, and the reaction was further carried out at the same temperature for 2 hours to obtain polymers B-1 to B-6 shown in Table 2. The results are shown in Table 2.

[0033]

[Table 2]

[0034]

[Synthesis Example 3] (Synthesis of High Molecular Polymer D) The compounds shown in Table 3 were charged into a flask equipped with a stirrer, a reflux condenser, and a thermometer based on the mixing ratio shown in Table 3, and heated to 40°C. The reaction was carried out for 3 hours, and polymers D-1 to D-7 shown in Table 3 were obtained. The results are shown in Table 3.

[0035]

[Table 3]

[0036]

[Synthesis Example 4] (Synthesis of vinyl monomer C) A flask equipped with a stirrer, a reflux condenser, and a thermometer was charged with the compounds and compounding ratios shown in Table 4, and the reaction was carried out at 40°C for 1 hour. As a result, vinyl monomers C-1 to C-2 shown in Table 4 were obtained. The results are shown in Table 4.

[0037]

[Table 4]

[0038]

[Synthesis Example 5] (Synthesis of High Molecular Polymer E) The reaction was carried out in the same manner as Synthesis Example 2 except that the solvent, monomer and polymerization initiator shown in the formulation in Table 5 were used. Combinations E1 and E2 were obtained. The results are shown in Table 5.

[0039]

[Table 5]

[0040]

[Examples 1 to 10, Comparative Examples 1 to 3] High molecular weight polymer D or E obtained in Synthesis Examples 3 and 5 and a crosslinking agent were mixed in the proportions shown in Table 6 to obtain a coating composition. Ta. The resulting coating compositions were then diluted using the trade name "Solvesso #100" to obtain respective coatings.

Next, zinc phosphate treatment (manufactured by Nippon Parkerizing Co., Ltd., trade name: "Bonderite #3004")
) on a steel plate coated with cationic electrodeposition paint (manufactured by NOF Corporation,
A coat of paint (trade name: "Aqua #4100") was applied to a dry film thickness of 20 μm and baked at 175°C for 30 minutes. A test board was prepared by coating it with ".1 Black") to a dry film thickness of 30 μm and baking it at 140° C. for 30 minutes.

On top of this, apply the previously prepared paint to a dry film thickness of 30
A test piece was prepared by spray painting to a thickness of μm and baking at 140°C for 30 minutes.

[0043] The obtained test piece was subjected to a coating film performance test using the method shown below. The results are shown in Table 6.

[0044]

[Table 6]

Test method and evaluation method 1. The scratch resistance test piece was fixed to the roof of a passenger car, and the condition of the coating film after being run through a car wash 20 times was visually evaluated.

◎: No abrasions at all ○: Very few abrasions △: Conspicuous abrasions ×: Extremely conspicuous abrasions 2. Spot 1 ml of stain-resistant Nisseki Silver gasoline on the test piece, and
After drying for 0 seconds, spot again. When this process was repeated 10 times, those with abnormalities such as blistering and sagging of the coating film were rated as x, and those with no abnormalities were rated as ○.

3. Water resistance test pieces were immersed in 40° C. hot water for 240 hours, and those with abnormalities such as blistering and distortion of the coating film were rated “×”, and those with no abnormalities were rated “○”.

4. Coating film hardness: Based on JIS K-5400 (1990) 8.4.2 manual scratching method.

As is clear from the results shown in Table 6, the coating composition of the present invention exhibits excellent scratch resistance, stain resistance, water resistance, and coating film hardness. In Comparative Examples 1 and 3, the content of compound A in the high molecular weight polymer D was
Since the content of Compound A is less than 10% by weight, the scratch resistance is poor. Furthermore, in Comparative Example 2, the content of Compound A exceeds 50% by weight in the polymer compound, resulting in poor stain resistance, water resistance, and coating film. Hardness has decreased.

Claims (2)

[Claims] 1. A polymer D obtained by reacting a compound A having an isocyanate group and a hydroxyl group obtained by reacting a diisocyanate compound and a diol compound with an amino group-containing vinyl polymer B; A coating composition containing a crosslinking agent, wherein the high molecular weight polymer D contains the compound A in an amount of 10 to 50% by weight. 2. Contains a compound A having an isocyanate group and a hydroxyl group obtained by reacting a diisocyanate compound and a diol compound, and a vinyl monomer C obtained by reacting an amino group-containing vinyl monomer. Contains a high molecular weight polymer E obtained by polymerizing raw material monomers and a crosslinking agent, and the high molecular weight polymer E has 10 to 10% of the compound A.
A coating composition characterized in that it contains 50% by weight.