DD241262A1 - STRUCTURAL VISCOSER PAINTED WITH HIGH RESISTANCE - Google Patents

Abstract

The invention relates to a pseudoplastic paint with high adhesion to metallic surfaces. To achieve high Strukturviskositaet and at the same time high adhesive strength is added to a known paint to about 30 wt .-% silica, which has at least a SiO 2 content of 90 Ma .-% and thereby is 95% present as amorphous silica and quartz sand or Gravel was made by evaporation at temperatures between 1,800 and 2,000C and condensing after rapid cooling to about 200C.

Description

Field of application of the invention

The invention relates to a pseudoplastic paint with high adhesion.

Criticism of the state of the art

Pseudoplastic paints are needed in the art.

Intrinsic viscosity is achieved by adding various substances.

As is known, a number of aids of different origin are suitable for adjusting the flow properties in terms of achieving intrinsic viscosity and the like. a, in paints. These include modified montmorillonites, hydrogenated ricin oils, urea derivatives, modified asbestos or metal salts of higher molecular weight fatty acids.

It is also known to use pyrolytically prepared or wet-chemically precipitated silica for this purpose.

Binders have an adhesion dependent on the constitution and are not always sufficient for use as a paint and must be brought into the range of sufficient adhesion to metallic substrate by addition of dispersed solids or suitable binder combination partners. As a result, however, hitherto existing positive properties, such as chemical and UV resistance, pushed back in favor of liability.

The previously used thixotropic agents cause no improvement in the adhesion in the paints, but affect them negatively.

Object of the invention

The aim of the invention is to produce a coating material with high structural viscosity and at the same time high adhesive strength on metallic surfaces.

Essence of the invention

The object of the invention is to produce a paint with high intrinsic viscosity and high adhesion to metallic surfaces.

Surprisingly, it has been found that a specially prepared silica solves the object of the invention.

According to the invention, this silica is obtained from quartz sand and gravel by evaporation at temperatures between 1 800 ⁰ C and 2000 ⁰ C and then rapidly cooling. This silica having the properties of the present invention has an SiO 2 content of at least 90 mass%, with 95% being amorphous silica and 5% being crystalline silicic acid. This silica is added to a level of 30% by weight of paints of known composition to provide high adhesion with thixotropic addition.

In contrast to other amorphous silicas having a high silanol group content and a high specific surface area, the amorphous silica used according to the invention has a low specific surface area and no detectable content of silanol groups. In contrast to those hitherto known technological possibilities of the use of amorphous silica in paints, which serve to achieve intrinsic viscosity, the variant proposed according to the invention is additionally effective in that in addition to the achievement of pseudoplastic flow properties an improvement in the adhesive strength is recorded.

This result is surprising and could not be expected in any way.

The solution according to the invention is explained in the following examples:

Example 1:

In a composition consisting of

35 ... 60% of a solution of a medium oil alkyd resin in xylene

59 ... 28% pigments and fillers

1 ... 2% excipients

5 to 10% solvent mixture, the characteristic value of the adhesive strength according to TGL 14302/05 was determined to be about 3. After the addition of 1% of the invention described amorphous silica, a characteristic value of 1 of the adhesive strength was achieved in addition to achieving pseudoplastic flow behavior.

Example 2:

In a composition consisting of

45 ... 60% of a solution of a low molecular weight chlorinated rubber

10 ... 15% auxiliaries and softeners

40 ... 15% pigments and fillers

5 ... 10% solvent mixture

After the measurement of the adhesive strength according to TGL 14302/05, characteristic values between 2 and 4 were determined. After addition of 1% of amorphous silica, in addition to the achievement of pseudoplastic properties, all test samples improved to the characteristic value 1 of the adhesive strength.

Claims (1)

Invention claim: Structural viscosity paint with high adhesive strength on metallic surfaces, characterized in that to achieve high intrinsic viscosity and high adhesive strength to a known paint of defined composition to about 30Ma .-% silica are added, the at least a SiO ₂ content of 90Ma .-% has 95% as amorphous silica and was prepared from quartz sand or gravel by evaporation at temperatures between 1800 and 2000 ⁰ C and condensing after rapid cooling to about 200 ° C.