DE2013301A1 - Process for coating the surfaces of panels - Google Patents

Description

PATENT ADVOCATE
D:? L-iNG.

HELKuT ÜÖRTZ

6 Frar.iuuri am Main 70
Sdinedcenhofetr. 27-Tel. 61 7079

■ 19. March 1970 Gzy / Ra.

Manufacture de Produits Ch.imi.ques Protex, Paris / France

Process for coating the surfaces of panels

The invention relates to a method of coating the surfaces of panels on one or both sides in order to close them protect and / or decorate with sheets of paper, Textiles or other porous materials.

Heretofore, sheets impregnated with a thermosetting resin have been used to cover panels. to such resins include the phenoplasts and the aminoplasts. The leaves were kept in this form until they were used stored. Rolled and impregnated paper, which is ready for use, was also used.

To cover a slab, one brought one or both of them a sheet on their surfaces, e.g. made of paper which was impregnated. The paper was previously made to the dimensions cut to size on the board. Then you brought the whole thing between the heated plates of a press. Under the action of heat and pressure, it melts to impregnate Resin used on the sheet, penetrates the plate, polymerizes and causes a connection between the sheet and the board.

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However, this known method has various disadvantages.

The sheets previously impregnated with the resin are proportionate expensive as their manufacture and drying are quite difficult. Rolls of impregnated paper only have certain dimensions. Since the panels to be coated have very different dimensions, there is a large attack of waste, which further increases costs. Impregnated paper rolls cannot be stored indefinitely, because the resin, which is not yet fully polymerized and stable, changes during storage.

The aim of the method according to the invention is to avoid it of the disadvantages mentioned.

The method according to the invention is characterized in that a liquid or paste-like resin in the form of a solution or an emulsion is applied to at least one surface of the board, and that immediately afterwards a sheet of paper not previously impregnated with a resin is applied to the surface coated with the resin , a textile or some other porous material, on this sheet then applies the layer of a resin identical or compatible with the first resin, and then brings the whole thing into a heated press, in which the resins under the action of pressure and heat converted into their final state and, if necessary, their surface is smoothed.

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This procedure is described in more detail below.

One brings in at least one of the surface of the board Resin in liquid or paste form, i.e. in Form of a solution or an emulsion. For this you can use known devices, which the application of a allow thin layer. ' .

Then shortly afterwards one brings up one or the two surfaces of the board covered with resin, at least one sheet of paper, fabric or one other porous material, which sheet is not previously impregnated with a resin.

A second resin layer is then preferably applied which is identical to or compatible with the first. Through this a complete impregnation of the leaf is guaranteed. This procedural step is special then recommended if the sheet is not completely impregnated by the first resin layer.

Finally, you put the whole thing in a press with heated plates, which is known per se. They use one there Pressure and a temperature which are sufficient for the polymerization of the resin and its To bring about transition to a final and stable state. This also improves the surface.

It is advantageous to dry the first resin layer beforehand, to remove water or the solvents used by evaporation. This procedural step is undertaken before

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the whole thing is brought into the press.

Any desired can be used for the method according to the invention use known natural and synthetic resins, such as caseins, albumins, phenoplasts, aminoplasts, condensation products of glycerine and phthalic acid or acrylic acid, and mixed resins. Instead of an aqueous solution you can a solution of the resin in an organic solvent can also be used.

The resin can contain other additives to facilitate the polymerization and to facilitate the impregnation of the sheet. In particular, plasticizers, dispersants, fillers, Add pigments and catalysts.

Sheets of paper of any type and thickness can be used, as well as fabrics, felts, fiber mats and the like.

The two surfaces of the board can be made of different leaves Art can be coated to achieve special decorative effects.

The panels can be produced in the same operation or shortly before the sheets are coated.

Particularly good results are obtained if liquid precondensates of formaldehyde and phenol are used as resins Resole type used in an aqueous or aqueous-alcoholic solution. The molar ratio of formaldehyde to Phenol should be between 1.5 and 2.5, the viscosity between 2 and 50 poises and the pH preferably between 7 and 12 lie.

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The concentration, the drying speed and the The rate of polymerization should be adapted to the paper used and the manufacturing equipment.

Thus, "for example, the drying speed of the resin solution of the drying apparatus be adjusted by controlling the content and the type of alcohol used, wherein the drying is controlled itself by the amount remaining in the resin volatiles, lon this proportion of volatile constituents will depend a good polymerization in the press, which leads to a good resistance and a good appearance of the surface.

The following examples show some embodiments the invention.

example 1

A sheet of okoume wood plywood with a length of 2500 mm, a width of 1220 mm, a thickness of 15 mm and seven layers made with a phenol-formaldehyde resin are glued together was used «You covered this Plate with an aqueous-alcoholic solution of a resol resin following properties:

Formaldehyde / phenol molar ratio: 1.8 Viscosity measured in a viscometer

according to HAAKB: 4 poises

Dry content after drying for 3 hours

at 105 ° Ct 50 1o

pH value: 8.8 + 0.5

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Reactivity according to ASTM: 17 + 3 minutes

Ethanol content: 10 ^.

This resin solution was used in an amount of 110 g of the resin

2
applied to each m. A non-impregnated paper weighing one square meter was placed on the board treated in this way

Resin of 40 g. A second layer of the /

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also applied by 100 g per m.

The panel was then dried in a ventilated chamber at 95 ° C for 15 minutes, which completely removed the solvents. Finally, the board was brought between the plates of a heated press, where it was ^{treated for 10 minutes at 120 °} C. under a pressure of 15 bar.

The panel thus produced had a very good decorative appearance. Which is particularly interesting for coating Concrete or cement, the slab completely withstood treatment with a 0.5 solution of for 24 hours Soda.

Example 2

One brought onto a board with the help of an order roll

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110 g per m of a urea-melamine-formaldehyde resin, here the resin 1576-6 from Societe PROTEX. This was followed by a paper weighing 40 g per square meter, which could be decorated, and then a second layer of the above-mentioned resin. It was dried and polymerized in a heated press for 10 minutes

at 100 ^° C. under a pressure of 12 bar.

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Example 3

On a sheet of Oregon Fiehte plywood

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180 g per m of a highly viscous phenolic resin were applied, in this case the resin L-114-6 from PROTEX. A jute fabric weighing 600 g per square meter was applied to this. A second one was placed on this fabric

2 layer of the resin in an amount of 220 g each. The whole was dried and treated in a heated press at 120 ^° C. for 20 minutes under a pressure of 12 bar.

The panels thus obtained can in particular be used for covering concrete, since they prevent the concrete from sticking and-give an abrasion-resistant surface. One can also Cover boards or boards of means of transport in this way, as well as boards for cladding the surface or the roofs of buildings and panels for furniture manufacture.

The method according to the invention has the following advantages with himself.

First, it is economical because there has been no waste to date expensive impregnated sheets used. A waste can at most not be impregnated cheaper Leaves emerge.

Second, the process simplifies and thus reduces costs. Up to now, the sheet used for covering had to be impregnated and stored beforehand, and only then had to be removed for covering the panels. Two process steps were therefore required for the leaves, the first for impregnation, the second for

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Obtain. In the process according to the invention, only a single process step is necessary.

Third, it avoids the storage of impregnated sheets, where the stability of the resin decreases over time.

Fourth, you can do several in a single process step make decorative patterns.

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Claims (4)

Claims η, J Process for one or both sides of the surface of boards to protect and / or decorate them, with sheets of paper, textiles or other porous materials, characterized in that at least one surface of the board is a liquid or pasty resin in the form of a solution or an emulsion is applied by immediately applying a sheet of paper, textile or other porous material not previously impregnated with a resin to the surface coated with the resin, then applying a layer to this sheet with the first resin that is identical or compatible with it, and then the whole thing is placed in a heated press in which the resins are pressed into theirs under the action of pressure and heat are ■ transferred to their final state / and, if applicable, their Surface is smoothed. 2. The method according to claim 1, characterized in that .daß the resin is a liquid precondensate of a phenol with formaldehyde of the resol type used in an aqueous or aqueous-alcoholic solution, the molar Ratio of formaldehyde to phenol between 1.5 and 2.5, the viscosity between 2 and 50 poises and the pH is between 7 and 12. 3. The method according to claim 2, characterized in that an aqueous-alcoholic solution of the resin is used, the molar ratio of formaldehyde to phenol / 1.8, 009842/1606 - ίο - the viscosity at 4 poises and the pH is 8.8, wherein the dry solids content after three hours of drying at 50 is i>, the solution contains 10 $ ethanol and ASTM has a reactivity of 17 minutes. 4. The method according to any one of claims 1 to 3 »characterized in that after applying the first Resin coating this before the further process steps by evaporation of the solvent, in particular the t water, dries. 009842/1606