CS253428B1 - Varnish composition for the surface treatment of leathers - Google Patents

Abstract

The solution relates to a varnish composition for surface treatment of leather, especially natural, spray. It solves the problem of optimal composition varnish composition with preferred physico-chemical vlastnosfami. The essence of the solution is that it contains, the total amount of varnish % of the composition, from 7 to 10% by weight. nltrocelulózy. 3 to 7 wt. saturated linear adipic acid-based polyester % and diethylene glycol, 0.5 to 2.5 wt. nonionic a surface tension reducing product prepared by polyaethylene oxide with castor oil dissolved in the mixture organic solvents

Description

The invention relates to a lacquer composition for the treatment of leather, in particular natural leather, consisting of nitrocellulose, a polymeric wetting agent, a surface tension reducing agent and a mixture of organic solvents.

Nitrocellulose-containing lacquer compositions are commonly used as protective coatings in the coating of leather. A film-forming finish consisting of nitrocellulose and a polymethane product in a ratio of 100: 140 wt. parts soaked with low molecular weight plasticizers of dibutyl phthalate and dioctyl phthalate type or dibutyl adipate and diactyl adipate. Known is a coating composition based on nitrocellulose-modified urethane, which is used for finishing leather. Another known lacquer composition comprises nitrocellulose, a polyurethane terminated by isocyanate groups released by the reaction of the polyisocyanate with an aliphatic polyol. Furthermore, a nitrocellulose lacquer is known which contains methylene tetrahydropyran in a solvent system. An important inhibitor of these coating compositions are plasticizers. In addition to the phthalate salts mentioned above, plasticizers such as castor oil and boiled rope oil are known. A disadvantage of these types is the tendency to migrate into the leather during storage, thereby making the surface coating brittle and reducing the abrasion resistance. Some types of lacquers require a special solvent system that is limited to the miscibility with nitrocellulose solvents, and thus the lacquer composition is poorly stable. The values of strength and ductility are in-line different and for each type it is disadvantage that one of them prevails.

These drawbacks are overcome by a lacquer composition comprising 7 to 10% by weight, based on the total amount of the lacquer composition. % nitrocellulose, 3 to 7 wt. of a saturated linear polyester based on adipic acid and diethylene glycol terminated with hydroxyl and carboxyl groups, with an acid number of 43 to 60 mg KOH / g, with a viscosity of 0.15 to 20 Pa. s at ^25? C, 0.5 to 2.5% by weight. a nonionic surface tension reducing product prepared by polyaddition of ethylene oxide with castor oil, with a surface tension of 35 to 38 nM / m, an iodine number of 22 to 28, dissolved in a mixture of organic solvents.

The technical effect of the invention is to optimize the strength and ductility values of the spray coating on the leather surface. The varnish composition provides optimum flexibility, resistance to dry and wet wiping and repeated bending resistance. The coating composition is stable and at reduced temperatures, is readily dilutable and can be applied by conventional coating equipment. Its preparation is simple and does not require special equipment or multi-stage technology.

The coating composition of the invention is illustrated in greater detail by the following examples, wherein the individual components are given in percent by weight, based on the total amount of the coating composition.

EXAMPLE

The lacquer composition was prepared as follows: 2 wt. % of a nonionic product, prepared by polyaddition of ethylene oxide with castor oil, with a surface tension of 35 mN / / m, an iodine number of 26, and 10.0 wt. nitrocellulose was dissolved in 42 wt. butyl acetate. After dissolution 5% w / w was added. a linear polyester based on adipic acid and diethylene glycol terminated by —OH and —COOH groups with an acid number of 55, a viscosity of 18 Pa. with. 2.5% w / w was added. % of monoethylene glycol monoethyl ether was added with stirring, and 38.5 wt. n-butanol. The resulting lacquer composition had a viscosity of 0.35 Pa. and diluted with 1: 1 butyl acetate prior to spray application.

Example 2

The lacquer composition was prepared as follows: 1.0 wt. % of a nonionic product prepared by polyaddition of ethylene oxide with castor oil, with a surface tension of 38 mN / m, an iodine number of 24, and 7 wt. nitrocellulose was dissolved in 30 wt. % butyl acetate and 22 wt. ethyl acetate. After dissolution, 5 wt. a linear polyester based on adipic acid and diethylene glycol terminated by —OH and —COOH groups with an acid number of 48, having a viscosity of 7 Pa. with. Further, 20 wt. % n-butanol and 16.5 wt. isobutanol until complete homogenization. The resulting lacquer composition had a viscosity of 0.235 Pa. with and for spray application, diluted with butyl acetate 1: 1.

Claims (1)

A lacquer pretreatment composition comprising nitrocellulose, a polymeric wetting agent, a surface tension reducing agent and a mixture of organic solvents, characterized in that it comprises, based on the total amount of the lacquer composition, 7 to 10% by weight. % nitrocellulose, 3 to 7 wt. of a saturated linear polyester based on adipic acid and diethylene glycol terminated with hydroxyl and carboxyl groups, having an acid number of 45 to 60 mg KOH / g, having a viscosity of 0.5 to 20 Pa. 0.5 to 2.5 wt. a nonionic surface tension reducing product prepared by polyaddition of ethylene oxide with castor oil, with a surface tension of 35-38 mN / m, an iodine number of 22-28, dissolved in a mixture of organic solvents.