CN1569986A

CN1569986A - High adhesion metal conditioner for coating metal

Info

Publication number: CN1569986A
Application number: CN 03132932
Authority: CN
Inventors: 王新兴; 何唯平
Original assignee: Shenzhen Oceanpower Industrial Co Ltd
Current assignee: Shenzhen Oceanpower Industrial Co Ltd
Priority date: 2003-07-21
Filing date: 2003-07-21
Publication date: 2005-01-26
Anticipated expiration: 2023-07-21
Also published as: CN100338159C

Abstract

The invention discloses a high adhesion phosphatized priming paint which is prepared by mixing component A and component B by the mass ratio of 5:1 and kneading homogeneously, wherein the composition A comprises 5-12% of polyvinyl alcohol butyraldehyde, 0.2-0.6% of moistening and dispersing agent, 0.1-0.6% of defoaming agent, 0.2-0.7 of thickening agent, 0.5-2% of fine stone flour, 40-50% of isopropyl alcohol, 1.5-2.5% of distilled water, 15-25% of ethanol, and 10-20% of n-butanol, and component B comprises 15-25% of phosphoric acid, 10-25% of distilled water, and 50-70% of isopropyl alcohol.

Description

High-adhesion phosphating primer for metal coating

The invention relates to a phosphatized primer, in particular to a phosphatized primer for metal coating.

The phosphatized primer, also called wash primer, cannot be used as the sole primer by itself, but is precoated before the application of the ordinary primer to form a very thin film (dry film thickness 8-15 μm) to increase the adhesion of the upper coating to the metal and the rust-preventive property, and has the dual functions of phosphating and metal passivation.

Before coating, themetal is usually treated by a phosphating treatment to enhance the adhesion of the coating to the metal and improve the corrosion resistance of the metal. If the top coating is directly applied to the metal surface, the adhesion is too poor because the metal surface is too smooth, and the corrosion resistance is greatly reduced because a phosphating film is omitted. When the workpiece cannot be phosphatized due to its large size or for other reasons, it is necessary to precoat the metal surface with a phosphatized primer. After the phosphatized primer is coated, the common primer and the finish paint are coated.

The phosphating priming paint has poor solvent resistance and weak salt-resistant dilute solution because the whole paint film of the phosphating priming paint is thin. Although the coating can resist the corrosion of high humidity air, the coating is easy to permeate by salt dilute solution or other organic solvents, and metal corrosion is caused after the salt dilute solution or other organic solvents permeate, so that the corrosion resistance of the whole coating is reduced. The traditional phosphating priming paint is soaked in butyl acetate for 1 hour, and the surface of a coating film is softened; the rust part of the crossed line diffuses more than 2mm to two sides after the salt spray resistance experiment for 48 hours.

Because the traditional phosphating priming paint has the defects of salt solution resistance, poor solvent resistance and the like, so that the defects of poor adhesion, corrosion resistance and the like of the priming paint coating are caused, and the traditional phosphating priming paint needs a phosphating priming paint with good salt solution resistance and good organic solvent resistance to replace the product.

The invention discloses a high-adhesion phosphating primer, which adopts polyvinyl butyral resin as a base material and tetrabasic zinc chrome yellow as a pigment, and is matched with a reasonable defoaming agent, a thickening agent and a wetting dispersant to prepare the primer which has good performance of resisting salt dilute solution or other organic solvents, and the coating has good adhesion and corrosion resistance; the defect of poor performance of the traditional phosphating priming paint in salt-resistant dilute solution or other organic solvents is overcome well.

The invention adopts polyvinyl butyral resin as base material and tetrabasic zinc chrome yellow as pigment. The polyvinyl butyral resin has many polar groups and is a strong adhesive resin, which becomes insoluble in a solvent by crosslinking of chromium and is combined with phosphoric acid, which is combined by reaction with a metal. The formed paint film is formed by resin and chromium together and becomes a chromium-hydrocarbon combined film, thereby promoting the passivation of the metal surface to play a role in corrosion prevention. Several reactions of film formation are as follows:

basic zinc chromate + H₃PO₄+ butyral resin → chromiumThe water content of the butyral resin chromate two-component phosphatized primer and the time elapsed after mixing with phosphoric acid can affect the chemical reaction between the butyral resin and the basic zinc chromate phosphoric acid, and thus the performance of the formed coating film.

The seal coat of the invention consists of A, B two components, wherein the component A comprises the following components:

5-12% polyvinyl butyral JDQ-X65

0.2-0.6% of wetting dispersant

0.1-0.6% of defoaming agent

0.2-0.7% of thickening agent

5-10% of tetrabasic zinc chrome yellow 309-zinc chrome yellow

0.5-2% extender pigment fine talcum powder 1500 mesh

40-50% isopropyl alcohol technical grade

1.5-2.5% of distilled water

15-25% ethanol technical grade

10-20% n-butanol technical grade

The preparation process of the component A comprises the following steps:

1. adding a defoaming agent and a wetting dispersant into the polyvinyl butyral resin, and uniformly stirring.

2. Under the condition of low-speed stirring, sequentially adding tetrabasic zinc chrome yellow and fine talcum powder, and pre-dispersing uniformly.

3. The various pigments were ground with a sand mill to a blade fineness of 10 μm or less. Care was taken that the milling temperature was not too hot to avoid the pigment reacting with the resin.

4. Under the condition of low-speed dispersion, adding a solvent and a thickening agent into the mixture, and filtering to obtain the component A of the high-adhesion phosphating primer.

The component B comprises the following components:

15-25% phosphoric acid (85%) technical grade

10-25% of distilled water

50-70% isopropyl alcohol

Mixing the solvents, and stirring to obtain component B.

When in use, the A, B two components are mixed according to the mass ratio of 5: 1 and stirred evenly to obtain the phosphatized primer. The viscosity is low, and the paint can be directly sprayed without dilution. The thickness of the dry film is controlled to be about 7-9 μm during spraying, and when the thickness is higher, the adhesion is not influenced, but the amount of the primer is increased, the cost is increased, and the anti-corrosion function of the coating film is not greatly improved. The coating can be dried at normal temperature, the color of the coating can be gradually deepened in the drying process until the coating becomes dark brown, and the coating is only about 7-9 mu m but enough to completely cover the substrate.

When the two are mixed, the color starts to be light yellow, and after a few minutes, the color will turn to yellow brown. Basic zinc chromate and phosphoric acid react. After mixing, the paint must be used within 8 hours, and after 8 hours, the mixed paint liquid does not gel but loses the performance characteristics.

The polyvinyl butyral JDQ-X65 resin used in the phosphating primers of the invention is 44-48% polyvinyl butyral resin containing butyryl groups and has excellent adhesion to a wide variety of surfaces. The thickener adopts DSX3256 of COGNIS company, is a nearly white clear liquid, is a nonionic polyurethane associative thickener, and has good film forming property and pigment wettability. The defoaming agent is H1620 of COGNIS company, is colorless to light yellow liquid, is a mixture of special alcohol and polysiloxane, and has excellent long-term defoaming property. The wetting dispersant is H5040 of COGNIS company, is yellow transparent viscous liquid, is a sodium polyhydroxy acid mixture, has excellent dispersion stabilizing effect on pigment and filler for water-based paint, and can ensure that the viscosity of the paint is very stable.

Compared with the prior art, the phosphating primer disclosed by the invention has the following obvious beneficial effects:

1. the phosphating primer coating has good organic solvent resistance, and the performance of the coating is not changed after the phosphating primer coating is soaked in butyl acetate for a long time.

2. The primer can promote the passivation of the metal surface to form a chromium-hydrocarbon combined film and has good corrosion resistance.

3. Has high adhesive force to metal substrates, and can be coated only by degreasing and deoiling the substrates. Under the same conditions, the adhesion force is grade 1 without adopting the phosphating priming paint, and the adhesion force is grade 0 after adopting the phosphating priming paint.

4. Good construction performance, and can obtain better coating according to conventional construction equipment and methods. The product can be completely dried at normal temperature for 20 minutes without baking, so that energy is saved; the drying time is short, the coating is convenient, and the construction time period is as long as about 8 hours.

5. Most of the solvent is alcohol, so that the harm to human bodies is small during production and construction.

6. The storage stability is good, various indexes (such as fineness, viscosity and the like) are basically not changed after the storage in a 50 ℃ oven for 2 months, and unstable phenomena such as precipitation, caking and the like do not occur.

7. The product can be used as the surface primer of common cold-rolled steel, and can also be used on the surfaces of other metal materials, such as: electrogalvanizing, hot dip galvanizing, aluminum materials, and the like.

In conclusion, the phosphating primer disclosed by the invention has good salt dilute solution resistance or other organic solvent resistance, the corrosion resistance and the adhesive force are greatly improved compared with those of the traditional primer, the application range is wider, the production process is the same as that of other solvent-based coatings, and the mass production is easy to realize. Therefore, the phosphating primer disclosed by the invention well overcomes various defects of the traditional phosphating primer and has higher practical value and popularization value.

Detailed Description

Examples

The A component of this sealer primer was prepared in the following proportions:

8.0% polyvinyl butyral JDQ-X65

0.4% wetting dispersant, H5040 COGNIS

0.3% of antifoam, H1620 COGNIS

0.4% of thickener, DSX3256 COGNIS

7.7% tetrabasic zinc chrome 309-zinc chrome

1.2 percent of extender pigment and 1500 meshes of fine talcum powder

45% solvent, technical grade isopropyl alcohol

2.0% solvent distilled water

19% solvent, ethanol technical grade

16% solvent, n-butanol technical grade (all percentages in this specification are percentages by weight)

The B component of the primer is prepared according to the following percentage:

18.5% phosphoric acid (85%) technical grade

16.5% distilled water solvent

65% isopropanol solvent

A, B are mixed according to the mass ratio of 5: 1, and the phosphatized primer is prepared after even stirring. Experiments prove that when the phosphating primer is used for spraying, the salt-resistant dilute solution or other organic solvent resistance of the coating is greatly improved, and the coating performance is not changed after the primer is soaked in butyl acetate for 100 hours; the corrosion resistance is greatly improved, and the rusty part of the crossed line is not diffused to two sides in a salt spray resistance experiment for 120 hours; the adhesive force reaches 0 grade. In conclusion, the phosphating primer disclosed by the invention well overcomes the defect of poor performance of the traditional primer in resisting salt dilute solution or other organic solvents, and the adhesive force and the corrosion resistance of the primer are greatly improved.

Claims

1. The high-adhesion phosphating primer consists of A, B two components, wherein the mass ratio of A, B two components is 5: 1, and the component A comprises the following components: