FI69651C - TAPET OCH FOERFARANDE FOER TILLVERKNING AV TAPET - Google Patents

Description

69651

This invention relates to a wallpaper having a wallpaper raw paper layer and a Pigment drip coating layer containing latex and pigments thereon for wallpaper printing methods such as glue, silk, flexographic and gravure printing.

5 Such wallpaper should be sufficiently washable. For example, a Timberley WPM instrument is used to determine washability, and method B, in which the abrasive surface is a felt and the medium is a 2% alkaline soap solution. It is considered a reasonable requirement that the wallpaper sample should withstand thirty to 10 strokes without damaging the surface.

Washing resistance can be increased by increasing the amount of latex.

In this application, latex refers to the so-called "latex" commonly used in wallpaper coatings. homo- or copolymer latexes, e.g. polyvinyl acetate homopolymer, polyvinyl acetate-acrylate copolymer, ethylene-vinyl acetate copolymer, styrene-acrylate copolymer, full acrylate and styrene-butadiene latex.

In practice to date, it has been found that the addition of latex to the Pigment Coating Layer in excess of twenty-five weight percent of the amount of pigments achieves sufficient wallpaper resistance of the wallpaper.

However, the addition of latex increases the cost of making the wallpaper because latex is expensive.

It has also been found that when using high latex contents, wallpaper printing methods generally do not achieve good line sharpness or a smooth compact surface because the ink tends to bead, which in turn is due to the deterioration of the absorbency of the pigment coating layer caused by the high latex content.

o 69651

Because latex has poor opacity, when the latex content is high, a lot of pigments such as titanium oxide, which has good opacity, must be used to counterbalance it. However, such a pigment is expensive.

In order to overcome the above-mentioned disadvantages, the object of the present invention is to increase the washing resistance of the wallpaper in a way other than by adding latex, whereby the proportion of latex in the pigment coating layer could be reduced. According to the invention, this object is achieved by applying an aqueous solution of inorganic salts of divalent or polyvalent metals, e.g. titanium, aluminum, calcium or magnesium, on the Pigment drip coating layer in order to increase the washing resistance and reduce the consumption of latex.

The invention is based on the surprising finding that when an aqueous solution of divalent or more inorganic salts of divalent metals is applied to a layer of pigment coating layer containing latex and pigments for wallpaper printing methods on top of a tufted raw paper layer. as a result, the proportion of latex in the pigment coating layer can be reduced to less than 10% of the amount of pigments while still maintaining the washability of the wallpaper. As the proportion of latex decreases, the cost of manufacturing the wallpaper is substantially reduced because the cost of the added solution is significantly lower than the cost of the latex and the well-opaque pigment and its printability properties are improved, as described above.

According to a preferred embodiment of the invention, the salt of the divalent or polyvalent metal is aluminum sulphate Al 2 (SO 2) 3 * 30 X H Q 0, where X is 14-18.

According to another preferred embodiment, the salt of the divalent or polyvalent metal is titanium chloride, zirconium sulphate, aluminum chloride, aluminum nitrate, zinc chloride, zinc sulphate or barium chloride.

3 69651

The invention also relates to a method of making a wallpaper, in which a raw paper layer of wallpaper is coated with a pigment coating layer containing latex and pigments for wallpaper printing methods such as glue, silk, flexo and gravure printing methods.

The process according to the invention is characterized in that an aqueous solution of one or more divalent metals, e.g. titanium, aluminum, calcium or magnesium, inorganic salt is applied to the pigment coating layer in order to increase the washing resistance and reduce the consumption of latex.

In addition, so-called double salts can be used, in which a divalent or polyvalent metal salt can be present together with a monovalent metal salt. Such double salts 15 are, for example, potassium alum, i.e. kalinite, cesium alum and sodium alum.

The application can be carried out, for example, by rollers, which can be used in various ways known in papermaking technology, or by spraying, in which case air is used in the application of the liquid, or by spraying. Impregnation, i.e. the immersion method, can also be used.

Prior to application of the saline solution, the pigment coating layer is dried to at least touch dry.

According to a preferred embodiment, the pigment coating layer 25 is applied to the printing paper moisture after application of the brine.

According to a preferred embodiment of the invention, aluminum sulphate Alg (SO) · XH 0, wherein X is 14-18, is used as the divalent or polyvalent metal salt in the process.

69651 k

According to another preferred embodiment of the invention, titanium chloride, zirconium sulphate, aluminum chloride, aluminum nitrate, zinc chloride, zinc sulphate or barium chloride are used as the divalent or polyvalent metal salt in the process.

According to a further preferred embodiment of the invention, the concentration of the aqueous salt solution is 0.5 to 10% by weight.

According to another preferred embodiment of the invention, the concentration of the aqueous salt solution is about 5% by weight.

In the following, the invention is illustrated by a practical example: EXAMPLE 1

Effect of latex content and after-treatment with 5% aluminum sulphate solution on washing resistance

a pigment coating

Latex 25.0 15.0 10.0

Pigments t

Titanium oxide 23.0 16.0 12-0 other pigments 77.0 84.0 88.0

Thickener CMC 0.3 0.6 1-0

Washing resistance not post-treated 40 (C) 20 (B) 5 (A) (abrasion resistant) ------—------

Timberley post - treated 150 (D) 100 (D) 40 (O

II

5 69651 EXAMPLE 2

Effect of latex content and post-treatment with 5% alum solution K „SO Al (SO) 2 4 2 4 3 24H ^ 0 on washing resistance Pigment coating layer

Latex 25.0 15.0 10.0

Pigments 100.0 100.0 100.0

Thickener CMC 1.2 1.2 1.2

Washing resistance not post-treated 40 (C) 25 (B) 15 (A) (abrasion-resistant) Timberley post-treated 130 (D) 100 (D) 50 (C) A = washing resistance quite poor B = "insufficient C = "sufficient D =" unnecessarily good (surface too closed)

The constituents of the pigment coating layer are calculated as a dry weight percentage of the amount of pigments.

The purpose of the thickener present in the pigment coating layer is to improve the smoothness of the pigment coating layer. Today, the most commonly used thickener is a water-soluble CMC substance, i.e. carboxymethylcellulose. Another property of this material is that it tends to degrade the washing resistance properties of the wallpaper.

Example 1 uses a 5¾ aluminum sulfate solution and Example 10 a 5% alum solution. It has been found in laboratory experiments that at 69651 6 already at a concentration of 0.5% the effect according to the invention begins to show.

Even at a concentration of 2%, the effect is clearly noticeable. The optimum effect, taking into account various factors, is achieved with a solution of about 5%. If the concentration of it is increased, the effect on the amount of latex 5 increases slowly. At concentrations above 10%, adverse effects begin to occur, e.g., the treated surface becomes mottled.

It can be seen from the example tables that by using the method according to the invention it has been possible to reduce the proportion of latex in the pigment coating layer from 25% to 10%, while still maintaining the washing resistance properties of the wallpaper sufficiently good. The proportion of titanium oxide in the total amount of pigments has been reduced from 23% to 12% (Example 1). At the same time, the manufacturing cost of the wallpaper has been reduced and the printability properties of the pigment coating layer have been improved. It can also be considered an advantage of the invention that, due to the very considerable reduction in the proportion of latex, the thickener can be safely used sufficiently to provide a good leveling for the pigment coating layer.

The reduced latex content also has the following benefits:

The pigment-coated waste paper formed prior to the treatment according to the invention decomposes easily and can thus be easily returned to the papermaking system.

Equipment used for coating is easier to clean. The biological oxygen demand (B0D) of wastewater is reduced.

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Claims (11)

69651 1. A wallpaper having a wallpaper raw paper layer and a pigment coating layer containing latex and pigments thereon for wallpaper printing methods such as glue, silk, flexo and gravure printing methods, characterized in that in order to increase the washing resistance and reduce the wear of the latex coating, an aqueous solution of inorganic salts of divalent or polyvalent metals, e.g. titanium, aluminum, calcium or magnesium, applied by printing. 10 2. Wallpaper according to Claim 1, characterized in that the salt of the divalent or polyvalent metal is an aluminum sulfate A1 _ (S 0.) „XH„ 0, in which X is 14-18. 2. j 2 Wallpaper according to Claim 1, characterized in that the salt of the divalent or polyvalent metal is titanium chloride, zirconium sulphate, aluminum chloride, aluminum nitrate, zinc chloride, zinc sulphate or barium chloride. Wallpaper according to Claim 1, characterized in that the concentration of the aqueous solution of the salt applied to the pigment layer is 0.5 to 10% by weight. Wallpaper according to Claim 1, characterized in that the concentration of the aqueous salt solution is about 5% by weight. The method for producing wallpaper according to claim 1, wherein the raw paper wallpaper layer is coated with a pigment coating layer containing latex and pigments for wallpaper printing methods such as glue, silk, flexo and gravure printing methods, characterized in that the pigment coating to increase the wash resistance 30 and reduce the consumption of latex, 69651 an aqueous solution of one or more divalent or more polyvalent metals, e.g. titanium, aluminum, calcium or magnesium, is applied. Method according to Claim 6, characterized in that, after application of the solution, the pigment coating layer is preferably dried to a printing paper moisture and then printed. Process according to Claim 6, characterized in that the salt of the divalent or polyvalent metal is aluminum sulphate Al 2 (SO 2) · XH 2 O, where X is 14-18. Process according to Claim 6, characterized in that the divalent or polyvalent metal salt is titanium chloride, zirconium sulphate, aluminum chloride, aluminum nitrate, zinc chloride, zinc sulphate or barium chloride. Process according to Claim 6, characterized in that the concentration of the aqueous salt solution is 0.5 to 10% by weight. Process according to Claim 10, characterized in that the concentration of the aqueous salt solution is about 5% by weight. 9 69651