KR100722748B1 - Coating composition and material having surface coated by same - Google Patents

Abstract

The present invention relates to a waterborne coating composition comprising a silicone-based compound, a fluorine-based compound, and a polyethylene-based compound mixed with a self-crosslinking aqueous acrylic emulsion, and further comprising an acidic compound. The present invention relates to a surface coating material excellent in lubricity at high hardness, good fouling resistance, normal temperature and high temperature obtained by heat treatment at 60 to 300 ° C.

Description

Coating composition and surface coating material {COATING COMPOSITION AND MATERIAL HAVING SURFACE COATED BY SAME}

The present invention relates to a waterborne coating composition comprising a silicone-based compound, a fluorine-based compound, and a polyethylene-based compound mixed with a self-crosslinking aqueous acrylic emulsion, and further comprising an acidic compound. The present invention relates to a surface coating material excellent in lubricity at high hardness, good fouling resistance, normal temperature and high temperature obtained by heat treatment at 60 to 300 ° C.

BACKGROUND ART Liquid medium dispersions of fine particles called emulsions, suspensions, latexes, and the like have been conventionally widely used as aqueous paints, adhesives, paper coating agents, leather base regulators, cement admixtures, film lubricants, and fiber binders. In the case where the coating film is formed by applying it to a steel sheet or a resin plate as an aqueous coating material, in recent years at the time of machining, together with the request that the coating film has abrasion resistance, fouling resistance, weather resistance, non-adhesion between the steel sheets and the resin plates, and a good appearance. Lubrication is required to omit oiling. Moreover, solvent resistance and alkali dissolution resistance are also required depending on the use.

In order to meet these demands, the coating film must be hard and have high lubricity, but it is difficult to harden the coating film with a conventional aqueous emulsion. In addition, in order to improve lubricity, it is easy to think of mixing a lubricant in an aqueous emulsion, but generally used lubricants and aqueous emulsions have poor mixing properties and often aggregate several days or instants. In addition, if the machining is performed continuously, the die of the processing machine is heated to a high temperature, but there is a problem that the high temperature lubricity of the coating film is not accompanied and the problem of sticking or changing the machining conditions occurs.

Therefore, a hard and lubricious coating film is currently obtained by heat-treating an organic solvent-based paint having a crosslinkable component such as melamine, epoxy, urethane, etc. at a high temperature of 200 ° C or 300 ° C, but recovery of volatilized organic solvent, Large scale furnaces are needed to obtain high temperatures. In addition, the invention disclosed in Japanese Patent Laid-Open No. 99-80485 describes an aqueous emulsion which crosslinks itself. However, in the present invention, the self-crosslinkable monomer has low reactivity, resulting in inferior heat treatment at low temperatures, and in terms of lubricity. There is no disclosure.

It is an object of the present invention to eliminate the drawbacks of the prior art, it is a complete water-based coating coating that can form a film excellent in high hardness, good stain resistance and appearance, lubricating performance at room temperature and high temperature even when heat treated at low temperature It is to provide a composition and a surface coating material coated with the coating.

In order to solve the above problems, the present invention has the following configuration.                     

That is, the present invention relates to an aqueous emulsion of an acrylic copolymer obtained by copolymerizing 2 to 30% by weight of a vinyl polymerizable self-crosslinkable monomer and other copolymerizable monomers in the presence of a nonpolymerizable emulsifier, and 2 to 10 based on a solid content of the aqueous emulsion. It is a coating composition which consists of a lubricating compound selected from the group which consists of a weight% silicone type compound, a fluorine type compound, and a polyethylene type compound as an essential component. The composition may contain 0.5 to 10% by weight of one or more acidic compounds selected from the group consisting of phosphoric acid compounds, sulfuric acid, nitric acid and hydrochloric acid, based on the solids of the aqueous emulsion, and the self-crosslinkable monomer is N-hydroxy. It is recommended to be selected from the group consisting of alkyl (meth) acrylamide, N-methoxyalkyl (meth) acrylamide, and glycidyl (meth) acrylate.

In addition, the present invention is formed by heat-treating such a composition at 60 to 300 DEG C, having a pencil hardness of 6H or higher, good stain resistance, a coefficient of kinetic friction at 25 DEG C of 0.15 or lower, and a coefficient of dynamic friction at 120 DEG C at 25 DEG C. Also included is a surface coating material coated with a coating that is less than 1.2 times that.

As described above, the self-crosslinking monomer is preferably selected from the group consisting of N-hydroxyalkyl (meth) acrylamide, N-methoxyalkyl (meth) acrylamide, and glycidyl (meth) acrylate. In addition, the self-crosslinkable monomer as used in the present invention has a functional group such as a hydroxyalkylamide group, a methoxyalkylamide group, or an epoxy group, and those functional groups (or other copolymerizable monomers employed in the copolymerization of the functional group with the present invention) (meth The compound group mentioned above is typical as what reacts with the carboxyl group of acrylic acid and the hydroxyl group of a hydroxyl-containing monomer. Specifically, N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-hydroxypropyl (meth) acrylamide, N-hydroxybutyl (meth) acrylamide, N- methoxymethyl (meth) acrylamide, N- methoxyethyl (meth) acrylamide, N- methoxypropyl (meth) acrylamide, N--methoxybutyl (meth) acrylamide, etc., that is, as the C ₁ ~ alkyl C ₄ can be mentioned. These self-crosslinkable monomers may be used independently and may be used as a mixture of two or more types. In addition, what is described as (meth) acryl ~ represents methacrylic-or acryl-, and it is the same also below.

Self-crosslinking monomers use from 2 to 30% by weight of the total amount of monomers forming an emulsion. If it is less than 2% by weight, pencil hardness, stain resistance, lubrication property at room temperature and high temperature deteriorate, and if it exceeds 30% by weight, stability as an aqueous emulsion is deteriorated and cannot be employed.

The other copolymerizable monomer is not particularly limited as long as it is copolymerized with the aforementioned self-crosslinkable monomer, but it is preferable to use one or more monomers selected from (meth) acrylic acid ester, styrene, (meth) acrylic acid, and hydroxyl group-containing monomers. Do. The total amount of these other copolymerizable monomers is 70 to 98% by weight in amounts excluding self-crosslinkable monomers.

As such (meth) acrylic acid ester, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, (meth) acrylate, secondary butyl (meth) acrylate, tertiary butyl (meth) acrylate, 2-ethyl hexyl and the like of the C ₁ ~C ₈ alkyl esters or (meth) acrylic acid-cyclohexyl. These monomers may be used independently and may be used as two or more types of mixtures.

The hydroxyl group-containing monomer mentioned above means having one or more hydroxyl groups in the alkyl chain of the (meth) acrylic acid alkyl ester, and as such a hydroxyl group-containing monomer, (meth) acrylic acid 2-hydroxyethyl, (meth) acrylic acid 2-hydroxypropyl, (Meth) acrylic acid 4-hydroxybutyl etc. are mentioned. These hydroxyl group containing monomers may be used independently and may be used as two or more types of mixtures.

The (meth) acrylic acid ester monomer, styrene, (meth) acrylic acid, and hydroxyl group containing monomer are used 70-98 weight% as mentioned above. If it is less than 70% by weight, the stability of the aqueous emulsion is poor, and if it is more than 98% by weight, the pencil hardness, stain resistance, solvent resistance, alkali dissolution resistance, and lubricity at high temperatures of the obtained film are deteriorated and cannot be employed. .

The emulsion of the present invention which copolymerizes such a monomer mixture into an aqueous system employs a nonpolymerizable emulsifier in polymerization. A nonpolymerizable emulsifier is a compound having a relatively high molecular weight, having a functional group having good compatibility with water, and not having an additional polymerizable functional group such as a vinyl group. The nonpolymerizable emulsifier is not introduced in the polymerization main chain formed by polymerization of the monomer. It is characterized by. The presence of this nonpolymerizable emulsifier is effective in view of the stability of the composition of the present invention as described below.

As nonpolymerizable emulsifiers, water-soluble protections such as polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, and polyacrylamide, in addition to anionic and nonionic surfactants such as sodium dodecylbenzenesulfonate and polyoxyethylene having a molecular weight of about 20,000. The thing synthesize | combined by polymerizing the monomer which has a colloid, a hydroxyl group, a sulfonic acid group, and a carboxyl group is mentioned. These nonpolymerizable emulsifiers can be used by mixing. In the case where no non-polymerizable emulsifier is used, aggregates are formed in the acrylic emulsion during the polymerization step, and as a result, the stability becomes poor or the miscibility of the silicone compound, fluorine compound, polyethylene compound, etc. mixed with the aqueous emulsion is poor. The use of is essential. Although the usage-amount also changes with polymerization conditions, it is about 1-5 parts per 100 weight part of monomer mixtures normally.

As a lubricating compound (henceforth a lubricating agent) added to such an aqueous emulsion, it selects from a silicone type compound, a fluorine type compound, and a polyethylene type compound, These are good even if it mixes and uses. These examples include Painted 51 [trade name manufactured by Dow Corning Asia Co., Ltd.], a silicone compound, KM-862 [trade name manufactured by Shin-Etsu Silicone Co., Ltd.], and Chemipearl W700 [Mitsui Chemical Co., Ltd.] which is a polyethylene-based compound. ], KSL-240A [trade name manufactured by Futaver Fine Chemicals Co., Ltd.], Meicatex HP-50 [trade name manufactured by Meisei Chemical Industries, Ltd.], sunleaf CLA-3 [Trade name manufactured by Sanyo Segoyo Co., Ltd.], pullon AD-1 which is a fluorine-based compound [trade name manufactured by Asahi IC Co., Ltd.], polypron LDW40 [trade name manufactured by Daikin Kogyo Co., Ltd.], etc. have. As the form of the lubricant when added to the aqueous emulsion, it is preferable that the particle diameter is 10 µm or less and wet, and the method of adding is preferably added in small amounts under the aqueous emulsion stirring.

Such a lubricant needs to contain 2 to 10 weight% with respect to the solid content of an aqueous emulsion. If it is less than 2% by weight, the lubricity is poor at both room temperature and high temperature, and if it is more than 10% by weight, aggregates are generated in the aqueous emulsion in the composition, resulting in poor stability of the composition itself. In addition, when a lubricant other than the one recommended by the present invention, for example, a linear alkyl acid compound such as a stearic acid compound, is used as a lubricant, even if the addition amount is 2 to 10% by weight, the composition aggregates within a few days. Throw it away. Moreover, the coating composition of this invention makes the above-mentioned water-based emulsion and 2-10% of the lubricating agent into an essential component, and may add a rust inhibitor, a thickener, an acidic compound mentioned later as other components.

By containing 0.5 to 10% by weight of an acidic compound with respect to the solid content of the aqueous emulsion described above, the crosslinking reaction of the self-crosslinking monomer is promoted, and even when heat-treated at a relatively low temperature of 60 to 120 ° C, good solvent resistance and alkali dissolution are eluted. A surface coating material having a property can be obtained. If the amount is less than 0.5% by weight, the effect as an accelerator is less. As a result, the solvent resistance and alkali dissolution resistance of the surface coating material at the time of heat treatment at low temperature are inferior. If the content is higher than 10% by weight, the pH of the coating composition itself is decreased. Significantly lowered, the safety of the operation is insufficient.

The acidic compound is preferably selected from the group consisting of phosphoric acid compounds, sulfuric acid, nitric acid and hydrochloric acid, and preferably has dissociable hydrogen ions. Phosphate compounds include ammonium dihydrogen phosphate, sodium dihydrogen phosphate, sodium dihydrogen phosphate, trisodium phosphate, sodium pyrophosphate, sodium polyphosphate, sodium metaphosphate, magnesium dihydrogen phosphate, aluminum monophosphate, hypophosphorous acid, Regular phosphoric acid and polyphosphoric acid are mentioned. These acidic compounds may be used independently and may be used as two or more types of mixtures.

Although the manufacturing method of the coating composition demonstrated above is not limited, If an example is shown, it is as follows.

That is, a predetermined amount of nonpolymerizable emulsifier and deionized water are put in a reaction tank to raise the temperature of the solution to 70 ° C. After this, the oil-soluble polymerization initiator was dissolved in a predetermined amount of the monomer mixture, or a predetermined amount of the monomer mixture was added dropwise with stirring to complete the mixture for 2 hours in parallel with an aqueous ammonium persulfate solution and an acidic sulfite solution. Subsequently, polymerization is performed while stirring at 70 ° C. for 2 hours to obtain an aqueous emulsion. Subsequently, the method of obtaining a composition by adding a small amount of a wet lubricant to the said aqueous emulsion under stirring at 10-50 degreeC and about 100 rpm is mentioned. Moreover, when adding an acidic compound, the method of adding to the said composition under stirring of 10-50 degreeC and about 100 rpm is mentioned.

As heat processing temperature of the film with respect to the coating object material which is the composition of this invention, 60-300 degreeC is good. If the heat treatment temperature is less than 60 ° C, the problem of difficulty in removing water as a solvent and the formation of crosslinking of the self-crosslinkable monomer part in the copolymer are insufficient, so that the pencil hardness of the film, the appearance of the film, lubricity at room temperature and high temperature This is bad, and when it exceeds 300 degreeC, it is unpreferable because the problem of decomposition | disassembly of a film starts gradually and burns off, the scale of the equipment to heat becomes large, and the equipment which forcibly cools a process material is needed. The film obtained from the composition of the present invention thus obtained is excellent material having a pencil hardness of 6H or higher, good stain resistance, a coefficient of kinetic friction of 0.15 or less at 25 ° C, and a coefficient of kinetic friction at 120 ° C of less than 1.2 times that at 25 ° C. Has Moreover, solvent resistance and alkali elution resistance are required according to the use of surface coating material. When using the coating composition of this invention which does not contain an acidic compound with such a requirement, the heat processing temperature of 120 degreeC or more is required, but the coating composition containing an acidic compound is excellent also in the heat processing temperature of 60 degreeC-120 degreeC. The film which has solvent resistance (4 grades or more by the evaluation method mentioned later) and alkali-elute resistance (10% or less by the evaluation method mentioned later) can be obtained.

Cold-rolled steel sheet as a material to be coated in the composition of the present invention. An aluminum plate, an aluminum alloy plated steel plate, a zinc plate, a galvanized steel plate, a zinc alloy plated steel plate, an ABS resin plate, etc. are mentioned, Especially when the steel plate is tested, since the lubricity of the low and high temperature general of the film mentioned above is good, continuous It is effective to endure press working and the like.

Hereinafter, the present invention will be described in more detail with reference to the following examples. In addition, each evaluation in an Example measured and determined by the following method.

1. Composition stability

About 30 ml of the composition which mainly consists of an aqueous emulsion was contained in 50 ml of glass bottles, the stopper was stopped, and it was left to stand at 50 degreeC for 1 month. The state of the emulsion after one month was visually determined.

○: Good without flocculation, thickening, sedimentation or separation                     

(Triangle | delta): Agglomerates and / or sediment generate | occur | produce.

×: gelation ...

2. Lubricity (dynamic friction coefficient)

After the composition mainly consisting of an aqueous emulsion is roll-coated on a base material such as a steel sheet, it is left to stand in a hot air dryer until it reaches a predetermined temperature, and the coating film is heat-treated. On the coating film cooled to room temperature, the weight was slid at a constant speed (10 cm / min) in a room adjusted to 25 ° C., and the load resulting from friction at that time was measured. The dynamic friction coefficient was computed by the following formula. Moreover, about the lubricity at high temperature, the electric heater was installed under the base material, the coating film was heated to 120 degreeC previously, and the dynamic friction coefficient at that time was measured by the said method.

(JIS K-7125)

Dynamic friction coefficient = weight of weight (g) / frictional load (gf)

3. Pollution resistance

After the composition mainly consisting of an aqueous emulsion is roll-coated on the base material, such as a steel plate, it is left to stand in the hot air dryer until it reaches predetermined | prescribed temperature, and a coating film is heat-treated. On a coating film cooled to room temperature, 2 ml of 10% carbon black aqueous dispersion was added dropwise at one point, and left in an 80 ° C. hot air dryer for 24 hours. The sample was taken out, and the part which carbon black was dripped was rubbed with wet etc. under pure water flow, and the carbon black adhesion state on the coating film was visually judged.

◎: not adhered                     

○: adheres thinly

△: noticeably attached ...

×: Clearly attached ··· Failed

××: is clearly attached and spreads around again

4. pencil hardness

After the composition mainly consisting of an aqueous emulsion is roll-coated on the base material, such as a steel plate, it is left to stand in the hot air dryer until it reaches predetermined | prescribed temperature, and a coating film is heat-treated. The hardness of the pencil which the coating film cooled to normal temperature was hardly scraped by the pencil of different hardness, and a coating film is not damaged was read.

5. Solvent resistance

After the composition mainly consisting of an aqueous emulsion is roll-coated on the base material, such as a steel plate, it is left to stand in the hot air dryer until it reaches predetermined | prescribed temperature, and a coating film is heat-treated. The coating film cooled to room temperature is rubbed with reciprocating five times with a load of about 1 kg by infiltrating ethyl alcohol with wet or the like. Thereafter, the appearance change on the coating film was visually determined.

5 (grade): no change in appearance

4 (class): change is recognized depending on the naked eye angle

3 (grade): slightly changed

2 (class): clearly changed

1 (grade): The film is peeled off.                     

6. Alkali dissolution resistance

The weight of the base material is measured in advance, and a composition mainly containing an aqueous emulsion is roll coated on the base material such as steel sheet, and then left to stand in a hot air dryer until a predetermined temperature is reached to heat the coating film. The weight of the coating film containing the base material cooled to normal temperature is measured, and coating film weight A is calculated | required. Subsequently, the aqueous alkali solution of Surfcleaner SD280MZ (trade name manufactured by Nippon Paint Co., Ltd.), which had been adjusted to 2% by weight in advance, was kept at 43 ° C, and the coating film containing the substrate was immersed therein for 2 minutes. After 2 minutes, taken out, washed with water and dried in a hot air dryer at 50 ° C. until no water is used. Then, the weight of the coating film containing a base material is measured again, the coating film weight B which remains on a base material after alkali treatment is calculated | required, and the alkali dissolution rate (%) represented by a following formula is calculated | required.

Alkali Dissolution Rate (%) = {1- (B / A)} × 100

7. Painting appearance

After the composition mainly consisting of an aqueous emulsion is roll-coated on the base material, such as a steel plate, it is left to stand in the hot air dryer until it reaches predetermined | prescribed temperature, and a coating film is heat-treated. The external appearance of the coating film surface cooled to normal temperature was visually determined.

○: no discoloration

△: slightly discolored

×: clearly discolored                     

Example 1

Synthesis of Nonpolymerizable Emulsifier

893 parts of deionized water (weight parts, the same below), 100 parts of monomers of the composition shown in the composition column of Table 1, 3 parts of ammonium persulfate, and 4 parts of acidic sodium sulfite are put into a reaction tank, and the temperature of a solution is raised to 70 degreeC, stirring. Subsequently, the polymerization reaction was performed while stirring at 70 degreeC for 12 hours, and the nonpolymerizable emulsifiers a to c which satisfy the present invention were synthesized. Table 1 also lists d to f, such as commercially available surfactants, which can be employed as the nonpolymerizable emulsifier of the present invention.

Non-polymerizable Emulsifier Furtherance Remarks a MAA / VSS = 70/30 b MAA / SPSS = 70/30 c MAA / VSS / HEA = 70/20/10 d PVA-217 (polyvinyl alcohol) Kuraray Co., Ltd. Products e OT-70 (anionic surfactant) Samyang Chemical Industry Products f Emulgen 130K (Nonionic Surfactant) Huawang Co., Ltd. Products

※ MAA: Methacrylic acid

※ VSS: Vinyl sulfonic acid soda

※ HEA: 2-hydroxyethyl acrylate

※ SPSS: p-styrene sulfonic acid soda

Example 2

Synthesis of Aqueous Emulsion

495 parts of deionized water (weight part, same below) and 5 parts of nonpolymerizable emulsifiers shown in Table 2 are put into a reaction tank, and the temperature of a solution is raised to 70 degreeC. 300 hours of the monomer mixture of the composition shown in the other copolymerizable monomer composition column of Table 2, the liquid which melt | dissolved 3 parts of ammonium persulfate in 97 parts of deionized water, and the solution which melt | dissolved 4 parts of acidic sodium sulfite in 96 parts of deionized water at the same time for 2 hours simultaneously The mixture was added dropwise with stirring to terminate the mixture, and then the polymerization reaction was carried out while stirring at 70 ° C. for 2 hours to satisfy the present invention. A to P were synthesized.

In addition, as a comparative example, the aqueous emulsion No. Q-V were synthesize | combined similarly by the monomer copolymerization ratio shown in Table 2. "Emulsion stability" of Table 2 evaluated visually that these aqueous emulsion was put into the sealed container and left to stand at 50 degreeC for 1 month, and (circle) shows favorable without aggregation, thickening, sedimentation, and separation, and (triangle | delta) is agglomerate and / Or sediment generate | occur | produces and x represents gelation.

Water-based emulsion Other copolymerizable monomer composition Self-crosslinking monomer type Self-crosslinking monomer amount (% by weight) Non-polymeric emulsifier Emulsion stability Remarks Water-based emulsion A i-BMA / n-BA = 62/36 N-MAM 2 a ○ Invention Water-based emulsion B MMA / n-BA = 51/44 N-MAM 5 b ○ Aqueous emulsion C MMA / n-BA = 49/41 N-MAM 10 b ○ Water-based emulsion D MMA / 2EHMA = 19/61 N-MAM 20 a ○ Aqueous emulsion E MMA / n-BA = 38/32 N-MAM 30 e ○ Water-based emulsion F MMA / n-BA = 53/45 GMA 2 a ○ Water-based emulsion G i-BMA / 2EHMA = 30/65 GMA 5 d ○ Aqueous emulsion H CHMA / n-BA = 54/36 GMA 10 a ○ Aqueous emulsion I MMA / n-BA = 38/32 GMA 30 f ○ Water-based emulsion J MMA / CHMA / n-BA = 29/30/39 N-MMAM 2 c ○ Water-based emulsion K MMA / n-BA = 51/44 N-MMAM 5 d ○ Water-based emulsion L MMA / n-BA = 49/41 N-MMAM 10 b ○ Water-based emulsion M MMA / n-BA = 38/32 N-MMAM 30 b ○ Water-based emulsion N St / n-BA / MAA = 35/45/15 N-MMAM 5 e ○ Aqueous emulsion O MMA / n-BA / HEA = 48/37/10 N-MMAM 5 d ○ Water-based emulsion P MMA / n-BA / MAA / HEA = 28/42/15/10 N-MAM 5 f ○ Water-based emulsion Q MMA / n-BA = 53/46 N-MMAM One a ○ Comparative Example Aqueous emulsion R MMA / n-BA = 35/30 N-MAM 35 a × Water-based emulsion S MMA / n-BA = 53/46 GMA One b ○ Water-based emulsion T MMA / n-BA = 51/44 N-MAM 5 (SPSS) ○ Water-based emulsion U MMA / n-BA = 51/44 (DvB) 5 b ○ Water-based emulsion V MMA / n-BA = 51/44 N-MMAM 5 - △

※ MMA: Methyl methacrylate

※ n-BA: n-butyl acrylate

I-BMA: Isobutyl methacrylate

※ 2EHMA: 2-ethylhexyl methacrylate

※ CHMA: cyclohexyl methacrylate

※ St: Styrene

※ MAA: Methacrylic acid

※ HEA: 2-hydroxyethyl acrylate

※ N-MAM: N-methylolacrylamide

※ N-MMAM: N-methoxymethylacrylamide

※ GMA: Glycidyl methacrylate

※ DvB: divinylbenzene

In Table 2, it can be understood that the water-based emulsions A to P satisfying the requirements of the present invention are well polymerized and have excellent stability of the resulting emulsion. On the other hand, R having excessive self-crosslinkable monomers and V which does not employ a non-polymerizable emulsifier already lack stability. Q and S with too few self-crosslinking monomers, T with SPSS, a polymerizable emulsifier, and U with DvB rather than self-crosslinking monomers have no problem in stability of the aqueous emulsion itself, but as shown below, a composition containing a lubricant This reveals a flaw.

Examples 3-7 and Comparative Examples 1-3

Using the aqueous emulsion C shown in Table 2, a coating composition (hereinafter simply referred to as a composition) in which the various lubricants shown in Table 3 were mixed with the amounts shown in Table 3 with respect to the solid content of the aqueous emulsion was adjusted. After roll-coating the film after heat-treating the composition on the aluminum plate so that it might become 3 micrometers, it heat-processed so that reached temperature might be 130 degreeC, and the surface-coated steel plate coated with the film of the coating composition was obtained. Table 3 shows the evaluation results of the surface properties of the steel sheet in addition to the stability of the composition.

From Table 3, it can understand that Examples 3-7 which satisfy | fill the requirements of this invention are also excellent in coating property, pencil hardness, and stain resistance, and are excellent also in lubricity from the dynamic friction coefficient in normal temperature and high temperature. Moreover, it is excellent also in solvent resistance and alkali elution resistance. On the other hand, Comparative Example 2 in which the mixing amount of the lubricant is too high or Comparative Example 3 using the lubricant of the stearic acid-based compound are insufficient in stability of the composition itself, and thus coating on the steel sheet cannot be achieved. Comparative Example 1, in which the mixing amount of the lubricant is too small, has no problem with stability of the composition itself, but lacks lubricity at room temperature and high temperature.

Examples 8-22 and Comparative Examples 4-8

After using the aqueous emulsion shown in Table 2, the coating composition which mixed 5 weight part of painted 51 (silicone compound) with respect to solid content of an aqueous emulsion was adjusted, and after heat-processing the composition on the steel plate of the various raw materials shown in Table 4, The film was roll-coated to have a thickness of 3 μm, and then heat-treated so that the achieved temperature was 130 ° C. to obtain a surface-coated steel sheet coated with the film of the coating composition. Table 4 shows the evaluation results of the surface properties of the steel sheet in addition to the stability of the composition.                     

Aqueous emulsion Composition stability Material Painted exterior Dynamic friction coefficient 120 ℃ / 25 ℃ dynamic friction coefficient ratio Fouling resistance Pencil hardness Content composition Alkaline Dissolution Rate (%) 25 ℃ 120 ℃ Example 8 Water-based emulsion A ○ Material 1 ○ 0.071 0.084 1.183 ○ 6H 4 0 Example 9 Water-based emulsion B ○ Material 1 ○ 0.055 0.065 1.182 ○ 7H 4 0 Example 4 Water-based emulsion C ○ Material 1 ○ 0.049 0.057 1.163 ◎ 7H 5 0 Example 10 Water-based emulsion D ○ Material 1 ○ 0.048 0.056 1.167 ◎ 8H 5 0 Example 11 Aqueous emulsion E ○ Material 1 ○ 0.050 0.057 1.140 ◎ 8H 5 0 Example 12 Water-based emulsion F ○ Material 1 ○ 0.068 0.079 1.162 ○ 6H 4 0 Example 13 Water-based emulsion G ○ Material 1 ○ 0.061 0.072 1.180 ○ 6H 4 0 Example 14 Aqueous emulsion H ○ Material 1 ○ 0.058 0.068 1.172 ○ 6H 5 0 Example 15 Aqueous emulsion I ○ Material 1 ○ 0.055 0.063 1.145 ◎ 7H 5 0 Example 16 Water-based emulsion J ○ Material 2 ○ 0.069 0.079 1.145 ○ 6H 4 0 Example 17 Water-based emulsion K ○ Material 2 ○ 0.060 0.070 1.167 ○ 7H 4 0 Example 18 Water-based emulsion L ○ Material 2 ○ 0.057 0.066 1.158 ◎ 7H 5 0 Example 19 Water-based emulsion M ○ Material 1 ○ 0.053 0.061 1.151 ◎ 8H 5 0 Example 20 Water-based emulsion N ○ Material 1 ○ 0.058 0.067 1.155 ○ 7H 5 82.4 Example 21 Water-based emulsion O ○ Material 1 ○ 0.052 0.061 1.173 ○ 7H 4 0 Example 22 Water-based emulsion P ○ Material 1 ○ 0.055 0.062 1.127 ○ 7H 5 100 Comparative Example 4 Water-based emulsion Q ○ Material 1 ○ 0.120 0.165 1.375 △ 4H 3 0 Comparative Example 5 Water-based emulsion S ○ Material 1 ○ 0.145 0.195 1.345 × 4H 3 0 Comparative Example 6 Water-based emulsion U ○ Material 1 ○ 0.155 0.198 1.277 × 4H 2 0 Comparative Example 7 Water-based emulsion V × - - - - - - - - - Comparative Example 8 Water-based emulsion T × - - - - - - - - -

※ Material 1: Aluminum Plate

* Material 2: electro galvanized steel

From Table 4, it can be understood that Examples 8 to 22 satisfying the requirements of the present invention are also excellent in paintability, pencil hardness, and stain resistance, and excellent in lubricity from the dynamic friction coefficient at normal temperature and high temperature. Except for Examples 20 and 22, solvent resistance and alkali dissolution resistance are also excellent. Examples 20 and 22 are inferior in alkali elution resistance. Although this is considered to be because it contains many MAA as a copolymerization component, it is fully practical for the use which is excellent in other performance and does not require alkali dissolution resistance. On the other hand, Comparative Examples 4 and 5 where the mixing amount of the self-crosslinking monomer is too small, Comparative Example 6 using DvB rather than the self-crosslinking monomer have no problem of stability of the composition itself, And Comparative Examples 7 and 8, which do not use a nonpolymerizable emulsifier, lack stability of the composition mixed with the lubricant.

Examples 23-32 and Comparative Examples 9-1

Using the aqueous emulsion C shown in Table 2, 5 parts by weight of the painted 51 (silicone compound) and various coating compounds mixed with the various acidic compounds shown in Table 5 were adjusted with respect to the solid content of the aqueous emulsion. The film after heat-treating the composition was roll-coated so that it became 3 micrometers, and it heat-treated so that it might reach | attained the achieved temperature shown in Table 5, and obtained the surface-coated steel plate coated with the film of the coating composition. Table 5 shows the evaluation results of the surface properties of the steel sheet in addition to the stability of the composition.                     

Acid compounds Composition stability Firing temperature (℃) Painted exterior Dynamic friction coefficient 120 ℃ / 25 ℃ dynamic friction coefficient ratio Fouling resistance Pencil hardness Content composition Alkaline Dissolution Rate (%) Operability Kinds Addition amount (%) 25 ℃ 120 ℃ Example 23 - - ○ 60 ○ 0.085 0.095 1.118 ○ 6H 3 26.5 ○ Example 24 - - ○ 80 ○ 0.067 0.078 1.164 ◎ 7H 3 20.4 ○ Example 25 Sulfuric acid 0.2 ○ 80 ○ 0.047 0.055 1.170 ◎ 7H 3 10.8 ○ Example 26 Regulation 0.5 ○ 80 ○ 0.047 0.054 1.149 ◎ 7H 4 0 ○ Example 27 Sulfuric acid One ○ 80 ○ 0.045 0.053 1.178 ◎ 7H 4 0 ○ Example 28 Regulation 2 ○ 80 ○ 0.046 0.053 1.152 ◎ 7H 5 0 ○ Example 29 Sulfuric acid 5 ○ 80 ○ 0.044 0.051 1.159 ◎ 7H 5 0 ○ Example 30 Regulation 10 ○ 80 ○ 0.045 0.052 1.156 ◎ 7H 5 0 ○ Example 31 - - ○ 120 ○ 0.055 0.065 1.182 ◎ 7H 4 5.5 ○ Example 4 - - ○ 130 ○ 0.049 0.057 1.163 ◎ 7H 5 0 ○ Example 32 - - ○ 270 ○ 0.043 0.051 1.186 ◎ 8H 5 0 ○ Comparative Example 9 - - ○ 50 △ 0.110 0.145 1.318 × 5H 2 29 × Comparative Example 10 - - ○ 320 × - - - - - - - - Comparative Example 11 Regulation 12 ○ 80 △ 0.043 0.050 1.163 ◎ 7H 5 0 ×

From Table 5, it can be understood that Examples 23 to 32 satisfying the requirements of the present invention are also excellent in paintability, pencil hardness, and stain resistance, and excellent in lubricity from the coefficient of kinetic friction at normal temperature and high temperature. Examples 4, 31, and 32, in which the heat treatment temperature is 120 ° C. or higher, are excellent in solvent resistance and alkali elution resistance. It is possible to make resistance and dissolution resistance. Moreover, although Examples 23-25 are slightly inferior to solvent resistance and alkali elution resistance, other performance is excellent and it is practical enough for the use which does not require solvent resistance and alkali elution resistance. On the other hand, in Comparative Example 9 in which the heat treatment temperature is too low, satisfactory film hardness cannot be obtained, and the stain resistance is also inferior. In Comparative Example 10 in which the heat treatment temperature is too high, the surface coating material and the lubricant decompose and do not reach the coating film evaluation. In Comparative Example 11, in which the mixed amount of the acidic compound is excessive, the coating appearance after the heat treatment is inferior, and the pH of the composition is considerably lowered.

According to the present invention, there is provided a coating composition, which is based on an aqueous emulsion having excellent safety and environmental aspects, and which provides a coating having a stable lubricity from low temperature to high temperature and a surface coating material coated with the coating. When the composition of the present invention is used, for example, in a steel sheet or the like, the steel sheet can also be subjected to continuous punching processing, which was conventionally impossible due to a decrease in lubricity at high temperatures.

Claims (5)

Copolymerization of 2-30% by weight of vinyl polymerizable self-crosslinkable monomer and one or more other copolymerizable monomers selected from the group consisting of (meth) acrylic acid ester, styrene, (meth) acrylic acid, and hydroxyl group-containing monomers in the presence of a non-polymerizable emulsifier A coating composition comprising, as an essential component, an aqueous emulsion of an acrylic copolymer and a lubricating compound selected from the group consisting of 2 to 10% by weight of a silicone compound, a fluorine compound, and a polyethylene compound, based on the solid content of the aqueous emulsion. The self-crosslinking monomer is selected from the group consisting of N-hydroxyalkyl (meth) acrylamide, N-methoxyalkyl (meth) acrylamide, and glycidyl (meth) acrylate. Coating composition. The method according to claim 1 or 2, characterized in that 0.5 to 10% by weight of one or more acidic compounds selected from the group consisting of phosphoric acid compounds, sulfuric acid, nitric acid and hydrochloric acid are contained relative to the solid content of the aqueous emulsion. Coating composition. It is formed by heat-treating the composition of Claim 1 or 2 at 60-300 degreeC, pencil hardness of 6H or more, stain resistance, the dynamic friction coefficient 0.15 or less at 25 degreeC, and the dynamic friction coefficient at 120 degreeC are 25 degreeC Surface coating material coated with a coating that is less than 1.2 times that in. It is formed by heat-treating the composition of Claim 3 at 60-300 degreeC, pencil hardness of 6H or more, pollution resistance, the coefficient of dynamic friction at 25 degreeC is 0.15 or less, and the coefficient of dynamic friction at 120 degreeC is 1.2 of 25 degreeC. Surface coating material coated with a coating less than twice.