CS195919B1 - Method of production of cover foils based on paper and textile strips impregnated with urea-formaldehyde resin - Google Patents

Abstract

The invention relates to a method of producing covering foils based on paper and textile strips impregnated with urea-formaldehyde resin, which are particularly suitable for the surface treatment of insert shelves or other interior surfaces in the furniture industry.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for the production of cover films based on paper and textile belts impregnated with urea-formaldehyde resin, which are particularly suitable for surface finishing of shelves or other interior surfaces in furniture.

It is known that coating foils based on unsaturated polyester resins are produced for surface treatment of wood material by impregnating special decorative printed papers with unsaturated polyester resins and then providing an asymmetric polyester lacquer layer.

This requires the use of relatively expensive resins and requires complex technical equipment. Polyester varnish solvents must be evaporated and cannot be recovered.

It is further known to produce aminoplast-based cover films. In this case, a so-called intermediate layer is applied between the aminoplast-impregnated carrier strip and the cover layer as an adhesion-promoting base or as an insulating base (DOS 2 124 218, D 06 m 7/00). The disadvantage here is that the support strip must first be impregnated and cured, then unilaterally painted and finally repainted. This process is very expensive and requires different technical conditions and equipment.

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The use of polyvinyl alcohol in aminoplast-impregnated papers is not yet known.

It is also possible to obtain a covering surface using high pressures of 0.12 to 0.40 ISdPa and press times of 5 to 30 minutes. The method thus does not allow the immediate production of the cover foil, since the major part of the chemical curing and the surface formation takes place only during the pressing, thus avoiding the use of a highly productive short-cycle pressing technology.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the drawbacks of the known processes and to develop a cover film based on urea-formaldehyde resins, in particular for inserting a shelf and interior furniture surface which can be manufactured rationally in one operation and processed by short cycle pressing technology.

According to the invention, the above object is achieved by impregnating a paper or textile web of 30 to 200 g / m @ ² with a solution of urea-formaldehyde resin with 25 to 60% by weight. The dry matter and the impregnated paper or textile web are applied asymmetrically with intermediate drying or wet process to a wet to ternary system consisting of 50 to 97% by weight, in particular 60 to 97% by weight. urea-formaldehyde resins, 1 to 25 why. wt. % polyvinyl alcohol and optionally up to 40 wt.%, in particular 10 to 30 wt. polyvinyl acetate and then cured.

If, for the intended field of application, the mechanical properties obtainable by the described process are not required, the covering layer can be formed by impregnating the carrier web with an asymmetric coating of 5 to 10 g / m ² polyvinyl alcohol and impregnating the carrier web with 25 to 60 % aqueous urea-formaldehyde resin solution.

The solution according to the invention results in a relatively resilient, resistant film on the film serving as a covering layer.

Compared to the unsaturated polyester resin based film, the inventive film provides the advantage of substantially lower material and manufacturing costs. The technical complexity of manufacturing this cover film is less than that of the prior art cover films.

The process according to the invention is illustrated by the following examples.

Example 1

The paper strip, printed with wood decoration, weighing 120 g / m ² is impregnated with the following mixture:

100 kg of a 50% solution of non-etherified urea-formaldehyde resin and a gel time of 5 minutes at 100 ° C, 1.5 kg of amine hydrochloride as a hardener.

On an impregnated web of 150 g / m ^{2 of} soaked impregnating resin (wet), 30 to 90 g / m ^{2 of} wetted 30 to 90 g / m ^{2 of a} blend consisting of 75 to 85 wt. % urea-formaldehyde resin with hardener, 10 to 20 wt. polyvinyl alcohol, and cures at 120-160 ° C.

The foil produced in this way and pressed onto the furniture panel has the following characteristics:

Abrasion resistance measured by Taber Abraser: 30

Porosity: 0

Sensitivity to stains after 24 h water: 1, after 1 h water: 0, sweat 1 h alcohol (40%): 0

Temperature state at 140 ° C: non-sticky.

Example 2

After pre-drying to a residual moisture content of 7 to 15 percent, 20 to 60 g / m @ ^{2 of} 35 to 50% of a mixture whose dry matter has the same composition as in Example 1 is applied to the decorative paper as in Example 1 and cured at 130 to 160 ° C. .

The surfaces obtained with the film thus produced have the following parameters:

Resistance to sanding: 50

Sensitivity to stains after 24 h water: 0, after 1 h alcohol (40%): 0

Temperature state at 140 ° C: non-sticky.

Example 1 a d 3

An unprinted pressed paper web of 80 g / m ² is impregnated with the following mixture:

100 kg of a 40% urea-formaldehyde resin, etherified with methanol, with a gelling time of 8 minutes at 100 ° C, 4 kg of a 40% aminohydrochloride solution.

Using a wet-to-wet process, 80 g / m @ ^{2 of} 25 to 30% by weight of a mixture whose solids consist of 55 to 65% by weight are deposited. % urea-formaldehyde resin with a hardener, 10 to 15 wt. % polyvinyl acetate, 20 to 25 wt. % polyvinyl alcohol and 5 to 10 wt. aercsil as a matting agent.

The sheet pressed onto the particle board has the following characteristics:

Resistance to sanding: 30

Porosity: 0

Sensitivity to stains 24 h water: 1, h water: 0, 1 h alcohol (40%): 1

Temperature state at 140 ° C: non-sticky.

Example 4

The decorative paper impregnated as in Example 2, and pre-dried is applied asymmetrically from 30 to 50 g / m ² A mixture of 80 vol% urea-formaldehyde resin with a hardener used for the impregnation, and 20% by volume from 15 to 20% polyvinyl alcohol aqueous solution and cured at 140 to 160 Deň: 32 ° C.

Resistance to sanding: 20

Porosity: 0

Sensitivity to stains 24 h water: 1, 1 h alcohol (40%): 0

Temperature state at 140 ° C: non-sticky.

Example 5

The decorative paper weighing 100 g / m ² is applied on the décor side from 50 to 100 g / m ² 15 to 20% polyvinyl alcohol solution and dried at a working speed of 50 m / min at · 120 ° C. The strip thus treated is analogous to; in Example 1, it is impregnated and dried at 120-160 ° C.

Resistance to sanding: 10 - 20

Porosity: 0 - 1

Sensitivity to stains 1 h water: 0 - 1, 1 h alcohol (40%): 0

Temperature state at 140 ° C: non-sticky surface.

Claims (7)

SUBJECT 1. A process for the production of coating films, matted or glossy, based on paper or fabric webs impregnated močovinoformaldehydíovými resins, the resins are added to močovinioformaldehydovým 'a hardener, characterized in that the paper or textile strips impregnated with a solution of urea-formaldehyde resin with a content of 25 to 80 ^IO / %, in particular 40 to 60 wt. and an asymmetrically two- or three-component system consisting of 60 to 97% by weight is applied to the impregnated paper or textile web. % urea-formaldehyde resins, 1 to 25 wt.%, in particular 3 to 20 wt. % polyvinyl alcohol, and optionally up to 40% by weight, in particular 10 to 30% by weight, of polyvinyl acetate and then curing. 2. A method according to claim 1, characterized in that the polyvinyl alcohol used in the coating system is applied to the decorative paper asymmetrically before impregnation and dried, and in the invention the treated paper is then impregnated with an impregnating solution as in step 1 and cured. Method according to Claims 1 and 2, characterized in that an impregnating resin having a weight of 30 to 70% by weight, in particular 35 to 55% by weight, based on the weight of the carrier, is used. 4. Method according to claim 1, characterized in that the coating is carried out by a wet-on-wet process or after the impregnated foil has been pre-dried. Method according to one of Claims 1 to 4, characterized in that a paper or textile web with a weight of 30 to 200 g / m ² , in particular 80 to 150 g / m ^{2, is used} . 6. A process according to claim 1, wherein the polyvinyl alcohol is used as the aqueous solution and the polyvinyl acetate is used as the aqueous dispersion. 7. The method according to claim 1, wherein the topcoat is applied in an amount of 5 to 100 g / m < ² >.