KR20090046263A - Resin composition for metal surface with excellent formability and lubricating property and method for treating metal surface using the same - Google Patents

Abstract

The present invention relates to a steel sheet surface treatment composition excellent in processability and surface lubrication and a surface treatment method of the steel sheet using the same, based on the solids weight of the total resin composition, (A) water-soluble or water-dispersible urethane resin and acrylic resin 30 to 70% by weight of the resin mixed at a ratio of 90:10 to 60:40; (B) 10-40% by weight of silica; (C) 0.1-3.0% by weight of a silane compound having at least one reactive functional group selected from the group consisting of epoxy, amino and methacrylic systems; (D) 3-25% by weight of one or more lubricants selected from the group consisting of paraffin wax, olefin wax, carnauba wax, polyethylene wax and polytetrafluoroethylene wax and residues And methods of treating metal surfaces using such compositions are provided.

Processability, Surface Lubricity, Urethane Resin, Acrylic Resin, Silica, Silane Compound, Lubricant

Description

Resin Composition for Metal Surface with Excellent Formability and Lubricating Property And Method for Treating Metal Surface Using the Same}

The present invention relates to a surface treatment composition of a metal material, a surface treatment method of a metal material using the same, and more particularly to a steel sheet surface treatment composition having improved processability, lubricity, solution stability, etc. It is about.

Galvanized steel, in particular, electro-galvanized steel, is the most widely used as a component material for home appliances and office equipment, but it is generally poor in workability and weatherability to be used without surface treatment. It is used after processing.

In the case of the phosphate treatment based on chemical reaction, in addition to the phosphate treatment process, additional treatment such as surface adjustment and water washing process are very disadvantageous in terms of economy and workability, and the film thickness becomes excessively thick, resulting in electrical conductivity. Because it is impossible to secure, it can only be applied in a limited range.

In addition, in order to improve the processability, the processing oil may be applied by applying oil. In this case, there is a possibility of poor coating due to problems in the working environment due to the scattering of the processing oil and occurrence of non-degreasing. Therefore, a method for lubricating solution for excluding processing oil and giving lubrication and processing characteristics of steel sheet has been proposed. However, these lubricating solutions contain a large amount of organic solvents, causing problems in stability and working environment, or even if they do not have sufficient performance to replace processing oils, they are still required for processing to steel products. Blackening of the surface is a problem.

The present invention has been proposed to solve the above-mentioned conventional problems, and an object of the present invention is to provide a resin composition for metal surface treatment which is excellent in workability, lubricity, workability, and the like of a metal surface and does not contain chromium.

Another object of the present invention is to provide a method for treating a steel sheet using the resin composition for metal surface treatment of the present invention.

The present invention is to achieve the above object,

As a first embodiment, based on the solids weight of the total resin composition, (A) 30-70% by weight of a resin mixture of water-soluble or water-dispersible urethane resins and acrylic resins in a resinous solids ratio of 90:10 to 60:40; (B) 10-40% by weight of silica; (C) 0.1-3.0% by weight of a silane compound having at least one reactive functional group selected from the group consisting of epoxy, amino and methacrylic systems; (D) 3-25% by weight of one or more lubricants selected from the group consisting of paraffin wax, olefin wax, carnauba wax, polyethylene wax and polytetrafluoroethylene wax and residues ,

As a second embodiment, the water-soluble or water-dispersible urethane resin is a metal surface treatment composition, characterized in that the coating film hardness of 3-5H,

As a third embodiment, the silica is a metal surface treatment composition, characterized in that the mixture of colloidal silica, fumed silica and ydri,

In a fourth embodiment, the silane compound is 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, or a mixture thereof. Surface treatment compositions,

As a fifth embodiment, the lubricant is a metal surface treatment composition, characterized in that a mixture of polyethylene wax and polytetrafluoroethylene wax,

As a sixth embodiment, the step of coating the metal surface treatment composition on a steel sheet so that the dry coating amount of 0.5-2.0g / ㎡; And

Baking the steel plate surface temperature in a temperature range of 80-200 ° C .;

Surface treatment method of a metal, comprising the;

The steel sheet is provided with a metal surface treatment method characterized in that the galvanized steel sheet.

The metal material surface treatment resin composition according to the present invention and the steel sheet surface treated by the metal surface treatment method of the present invention are excellent in workability, lubricity, coating adhesion, and storage stability of solution. In addition, since the resin composition of the present invention does not contain chromium and a solvent, it is environmentally friendly, and there is no problem of deterioration of working environment or danger.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

Metal surface treatment composition of the present invention, based on the solids weight of the total resin composition, (A) a resin mixed with a water-soluble or water-dispersible urethane resin and acrylic resin; (B) silica; (C) silane compound; And (D) lubricants; And remainder water is included.

The resin of the metal surface treatment composition of the present invention uses a urethane resin having excellent processability and chemical resistance and an acrylic resin having excellent corrosion resistance, wherein the mixing ratio of the urethane resin and the acrylic resin is 90:10 to 60:40 based on the resin solid content. It is preferable to mix in the ratio of. If the content of the urethane resin in the resin solid content is less than 60%, it is difficult to expect the effect of improving the workability, and if it exceeds 90%, it is disadvantageous in improving the economics and corrosion resistance.

This resin mixture is used to be 30-70% by weight based on the solids content of the entire resin composition. If the resin content is less than 30% by weight relative to the solid content of the resin composition, the target lubricating film cannot be obtained, and the hardness of the coating film does not increase, which does not help to improve workability, and when it exceeds 70% by weight, other additives Its solubility is poor and gelation is easy, which is not preferable.

It is preferable that the urethane resin of the said resin is 3H-5H of coating film hardness. When it exceeds 5H, the hardness of the coating film is too high, so cracking of the coating film occurs during processing, and when it is less than 3H, it is difficult to expect an effect of improving workability.

The metal surface treatment composition of the present invention includes silica for improving processability and corrosion resistance. It is preferable to use colloidal silica, fumed silica and mixtures thereof as the silica.

The silica is preferably added in 10-40% by weight of the total solids of the metal surface treatment composition of the present invention. If the silica is less than 10% by weight, the effect of improving physical properties is insufficient, and if it exceeds 40% by weight, the coating film becomes too hard and easily breaks during processing, which causes scratches on the coating film, which adversely affects corrosion resistance.

In the metal surface treatment composition of the present invention, a silane having at least one reactive functional group selected from the group consisting of epoxy, amino and methacrylic compounds is used to improve the adhesion between the coating film and the base steel sheet and to increase the crosslinking degree of the coating film. Compounds can be added. Preferred silane compounds that can be used in the present invention include 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane and the like, but are not limited thereto. It is not.

The silane compound is preferably added 0.1-3% by weight of the total solids of the metal surface treatment composition. If the silane compound is less than 0.1% by weight, the effect of improving adhesion, coating coating property and corrosion resistance is insufficient, and when it exceeds 3% by weight, solution stability is drastically lowered.

In addition, the metal surface treatment composition of the present invention may be added a lubricant for improving workability and impart self-lubrication. Such lubricants include, but are not limited to, water soluble paraffin wax, olefin wax, carnauba wax, polyethylene wax and polytetrafluoroethylene wax. The wax may be used in one kind or in a mixture of two or more kinds. In particular, it is more preferable to mix polyethylene wax and polytetrafluoroethylene wax.

The lubricant may be added in 3-25% by weight based on the total solids of the metal surface treatment composition of the present invention. If the lubricant content is less than 3% by weight, the coating film is not sufficiently lubricated, and thus less effective in improving workability and formability. If the content is more than 25% by weight, no further lubrication effect is exhibited. There is a problem such as that the stability of.

The metal surface treatment composition of the present invention comprises water in addition to the above components as an aqueous lubricating resin composition. In addition, additives such as curing agents, antifoaming agents, and wetting agents, which can be generally added in the art, may be included as necessary.

The metal to which the resin composition for surface treatment of the present invention is applied is not particularly limited, but a galvanized steel sheet is preferable, and in particular an electrogalvanized steel sheet is more preferable.

EMBODIMENT OF THE INVENTION Hereinafter, the metal surface treatment method using the metal surface treatment composition of this invention is demonstrated.

After coating the resin composition solution for metal surface treatment according to the present invention on the surface of the steel sheet, the coated steel sheet is baked for several seconds, air-cooled or water-cooled to produce a surface-treated steel sheet.

The coating of the aqueous resin composition may be applied to a steel sheet by a conventional method such as a roll coater method, a shower squeeze method, a deposition method, a spray method, and the like to prepare a surface-treated steel sheet.

Coating of the resin composition of this invention on the surface of a steel plate is preferable to coat so that dry coating film adhesion amount may be 0.5-2.0 g / m <2>. If the dry coating film is less than 0.5g / ㎡ the workability, corrosion resistance and the like is insufficient, there is a problem that the conductivity, weldability and paint adhesion is inferior when exceeding 2.0g / ㎡.

In the case where the surface-coated metal is baked afterwards, the surface temperature of the steel sheet is preferably 80-200 ° C. If the steel sheet surface temperature is lower than 80 ℃, the resin will not be cured sufficiently and it is difficult to expect a sufficient effect due to the formation of a coating film.If it exceeds 200 ℃, cooling of the steel sheet after drying is not easy and carbonization of resin, etc. The overall performance can be reduced due to the deformation of the coating composition of the film.

As described above, the steel sheet treated with the metal surface treatment composition according to the present invention is not harmful to the human body because it does not contain chromate and thus does not cause environmental pollution.

Hereinafter, the present invention will be described in more detail with reference to the following examples.

Example 1

The urethane resin and the acrylic resin having a hardness of 3H are mixed at a resin solids ratio of 80:20 so that its solid content is 60% by weight relative to the solid content of the entire resin composition, and the colloidal silica (B1) is solid content of the entire resin composition. The mixture was added in an amount of 24% by weight, and the mixture was sufficiently stirred. Then, 3-glycidoxypropyltrimethoxysilane (C1) was sufficiently stirred while gradually adding 1% by weight to the total solid of the resin composition. Then, polyethylene wax and polytetrafluoroethylene wax were added so as to be 7.5% by weight based on the total solids of the resin composition. It was then diluted with deionized water to a suitable solid for the coating.

The water-soluble steel sheet surface treatment composition thus prepared was bar-coated on an electrogalvanized steel sheet having a plating deposition amount of 20 g / m 2 on one side so as to have a dry coating amount of 0.8 g / m 2, and then baked until the steel sheet temperature reached 120 ° C. Dried.

[Examples 2 to 6 and Comparative Examples 1 to 6]

A resin composition was prepared in the same manner as in Example 1, except that the type, amount, baking temperature, and dry coating amount of the resin, silica, silane compound, and lubricant were changed as shown in Table 1 below, and the surface of the steel sheet was used. The treatment was performed.

Resin ratio urethane (hardness): Acrylic Added amount (% by weight in total solids) Baking temperature (℃) Amount of adhesion (g / ㎡) Suzy Silica Silane slush    Example One 80 (3H): 20 60.0 B1 (24) C1 (1.0) D1 (7.5) D2 (7.5) 120 0.8 2 70 (3H): 30 59.5 B1 (30) C1 (0.5) D2 (10) 150 1.0 3 70 (3H): 30 63.0 B1 (20) C2 (2.0) D1 (15) 150 1.5 4 60 (3H): 40 43.5 B1 (40) C2 (1.5) D1 (10) D2 (5) 120 0.8 5 80 (3H): 20 67.0 B1 (10) C3 (3.0) D1 (10) D2 (10) 150 0.5 6 70 (3H): 30 52.5 B1 (20) C1 (2.5) D2 (25) 80 2.0   Comparative example One 70 (3H): 30 68.0 B1 (30) C1 (2.0) - 150 0.8 2 80 (3H): 20 54.0 B1 (10) C2 (1.0) E2 (35) 180 1.5 3 70 (3H): 30 55.0 B1 (25) C3 (10) D1 (5) D2 (5) 100 1.0 4 70 (3H): 30 53.0 B1 (30) C2 (2.0) D1 (5) D2 (10) 100 0.3 5 70 (1H): 30 58.5 B1 (25) C2 (1.5) D1 (15) 80 1.0

C: silane compound

C1: 3-glycidoxypropyltrimethoxysilane

C2: 3-aminopropyltrimethoxysilane

C3: 3-mercaptopropyltrimethoxysilane

D: lubricant

D1: polyethylene wax

D2: polytetrafluoroethylene wax

The steel sheet coated with the above conditions was measured for workability, lubricity, coating adhesion, and storage stability of the prepared solution.

[Processability]

The surface of the test piece was visually evaluated after reciprocating 10 times at a load of 0.25 kgf / mm 2 using a Tribometer tester. Evaluation criteria are as follows.

○: almost no blackening

△: blackening partially occurs in the evaluation site

×: Blackening of entire evaluation site

[Lubrication]

Lubricity was measured for the coefficient of kinetic friction using a drawbead tester. The smaller the friction coefficient, the better the lubricity. Evaluation criteria are as follows.

○: Friction coefficient 0.100 or less

△: friction coefficient 0.100 to 0.120

×: coefficient of friction over 0.120

[Coating Adhesion]

AMILACK # 1000 (manufactured by Kansai Paint Co., Ltd.) was coated on a test plate coated with the resin composition of the present invention so as to have a dry coating thickness of 25 μm, dried at 140 ° C. for 20 minutes, and then the test plate was plated at 1 mm intervals. The cell adhesive tape was affixed to the part which cut off 100 scale marks, and the coating adhesiveness was evaluated by removing this. Evaluation criteria are as follows.

○: no peeled spots

×: one or more peeled spots

[Storage stability]

After storing the prepared resin composition solution in a thermostat at 40 ℃ for 2 months, the state of the viscosity rise, separation, precipitation, etc. of the composition was observed. Evaluation criteria are as follows.

(Circle): The change of a composition is not recognized.

X: Changes in viscosity increase, separation or precipitation of the composition are recognized.

The evaluation results according to the above are summarized in Table 2. As shown in Table 2, in Examples 1-6 using the treatment composition according to the present invention, it was proved to be excellent in workability, lubricity, paint adhesion, and the like, and particularly excellent in workability.

However, Comparative Example 1, in which the wax as a lubricant component was not included, was inferior in workability and lubricity. On the other hand, Comparative Example 2, the content of the lubricant component exceeds the range of the present invention was very inferior to the paint adhesion. Comparative Example 3 in which the content of the silane compound exceeds the range of the present invention has a problem in storage stability. The comparative example 4 whose dry coating film adhesion amount of a surface treatment composition is less than the range of this invention had insufficient workability. Finally, the comparative example 5 in which the hardness of the urethane resin used as a resin component was out of the range of this invention was inferior to workability.

Machinability Lubricity Paint adhesion Storage stability Example 1 ○ ○ ○ ○ Example 2 ○ ○ ○ ○ Example 3 ○ ○ ○ ○ Example 4 ○ ○ ○ ○ Example 5 ○ ○ ○ ○ Example 6 ○ ○ ○ ○ Comparative Example 1 × × ○ ○ Comparative Example 2 ○ ○ × ○ Comparative Example 3 ○ ○ ○ × Comparative Example 4 × △ ○ ○ Comparative Example 5 × ○ ○ ○

Claims (7)

(A) 30-70 weight% of resin which mixed water-soluble or water-dispersible urethane resin and acrylic resin by 90:10-60:40 by resin solid content ratio on the basis of the solid content weight of the whole resin composition; (B) 10-40% by weight of silica; (C) 0.1-3.0% by weight of a silane compound having at least one reactive functional group selected from the group consisting of epoxy, amino and methacrylic systems; (D) 3-25% by weight of one or more lubricants selected from the group consisting of paraffin wax, olefin wax, carnauba wax, polyethylene wax and polytetrafluoroethylene wax and residues . The metal surface treatment composition according to claim 1, wherein the water-soluble or water-dispersible urethane resin has a coating film hardness of 3-5H. The metal surface treatment composition according to claim 1, wherein the silica is a mixture of colloidal silica, fumed silica, and idri. The metal according to claim 1, wherein the silane compound is 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, or a mixture thereof. Surface treatment composition. The metal surface treatment composition according to claim 1, wherein the lubricant is a mixture of polyethylene wax and polytetrafluoroethylene wax. Coating the surface treatment composition of any one of claims 1 to 5 on the surface of the steel sheet so that the dry coating amount is 0.5-2.0 g / m 2; And Baking the steel plate surface temperature in a temperature range of 80-200 ° C .; Metal surface treatment method comprising a. 7. The method of claim 6, wherein the steel sheet is a galvanized steel sheet.