FI91785B - Wallpaper - Google Patents

Description

91785

Wallpaper

The invention relates to a wallpaper comprising a coating layer comprising a latex binder and a pigment on a base paper, having a surface coating containing 100 parts per pigment particle of at least 25 parts of latex binder and in an amount of at least 20 g / m 2 dry, the total amount of the coating layer being at least 10 30 g / m2.

Polyvinyl chloride (PVC) is now commonly used as a coating in wallpapers. This material has been used as a coating mainly due to its protective effect, such as good resistance to moisture, grease and mechanical stress.

However, the use of PVC in coatings has some disadvantages. One such disadvantage is the waste problem due to the recycling problems of the used wallpaper on the one hand and the waste from the PVC coating process itself on the other hand, and another problem is the equipment and chemicals required by the process itself. In the coating, polyvinyl chloride is subjected to the so-called to the surface of the web 25 to be coated as a plastisol. Such a plastisol consists of a plasticizing medium, which is generally an ester of an aromatic acid and an aliphatic long-chain alcohol, e.g. dioctyl phthalate, and fine PVC particles suspended therein. In process 30, a uniform solid coating is obtained by heating a flowable plastisol deposited on the web to about 150 ° C. In order to obtain a decorative surface relief, such a coating can be heat-treated (so-called hot-spraying).

35

The aforementioned coating process requires special equipment and the use of organic aromatic chemicals causes handling and waste problems. As a disadvantage of the finished product, it can be mentioned that the PVC coating generates toxic substances when burned, e.g. hydrochloric acid, which reduces the fire safety of the wallpaper.

German Patent 2501684 discloses a wallpaper coating in which the coating contains an aqueous styrene-butadiene latex as a binder and a pigment which may be insoluble starch or a mixture of calcium carbonate and calcium silicate.

10 The amount of such coating on the base board is generally 8-15 g / m2. Disadvantages of a coating containing only an inorganic pigment have been mentioned in this publication that it is too glossy, rough and has unsatisfactory deep displaceability after calendering, in addition to which the wet abrasion resistance decreases substantially when roughened.

British Patent Application Publication No. 2201613 discloses a wallpaper coating comprising a water-based acrylic or vinyl acetate-based binder together with a flame retardant and an inorganic coating pigment. The fire-resistant product according to this publication has a considerably better wet abrasion resistance than the wallpaper product disclosed in the above-mentioned German patent 25, but such a coating composition does not meet the requirements for a PVC coating. For example, the most important of the properties that the product lacks is the heat separability of the coating surface.

30

The object of the invention is to provide a coated wallpaper which, on the one hand, can replace PVC-coated wallpaper and at the same time has good matt, good ink absorption, good wet abrasion resistance, smoothness and deep penetrability and which on the other hand is well both heat-crackable and cold-sprayable.

To achieve this purpose, the wallpaper according to the invention is mainly characterized in that the pigment particles of the surface coating comprise at least 5 parts of 5 particles of thermoplastic halogen-free polymer, the remainder being mostly inorganic pigment. Thanks to its high binder content, high basis weight coating and thermoplastic polymer component, it has surprisingly been possible to obtain a wallpaper which does not differ externally from PVC-10 coated wallpaper but which is more environmentally friendly due to the raw materials used, disposal and post-use disposal. the more fireproof it is. Thanks to the thermoplastic polymer particles 15, it is possible to obtain a good and permanent heat separation pattern. However, the wallpaper is not inferior to PVC-coated wallpaper, being even better in some respects.

According to a preferred embodiment, the thermoplastic halogen-free polymer comprises at least 10 parts, preferably more than 20 parts, of the pigment particles. In order to achieve good coating application properties and good printability, there are up to 60 parts of polymer with the remainder being an inorganic pigment.

According to another preferred embodiment, the latex binder is preferably 40 to 65 parts per 100 parts of pigment particles.

The coating layer may further comprise a pre-coating layer comprising a latex binder and a pigment between the surface coating and the base paper, containing at least 35 8 parts, preferably 10-25 parts of latex binder per 100 parts of pigment particles.

The pre-coating layer may consist of two different pre-coating layers applied in step 91785 4. The precoat layer provides good smoothness before the topcoat and is at least 8 g / m 2, preferably 10-25 g / m 2.

5

According to a preferred embodiment, the inorganic pigment of the surface coating comprises both magnesium silicate (talc) and calcium carbonate, and the ratio of the amounts of magnesium lithium to calcium carbonate 10 can then vary, for example, between 3: 1 and 1: 3. These inorganic pigments provide a good matte surface, in addition to which the use of calcium carbonate can reduce the wetting agent required for the dispersibility of the talc, which would make the coating 15 too hydrophilic.

The invention will now be described in more detail with reference to the accompanying drawing and certain coating compositions for the production of wallpaper according to the invention.

In the drawings, Fig. 1 shows a wallpaper according to the invention in cross-section, Fig. 2 shows another wallpaper according to the invention in cross-section, and Fig. 3 shows a wallpaper with a roughened coating.

30

In the following description, the substances are always given in terms of dry matter, unless otherwise stated.

Figure 1 shows a coating layer 2 applied on the base paper 1. The coating layer has a surface coating PP containing 100 parts per pigment particle of at least 25 parts, preferably at least 30 parts of latex binder and in an amount of at least 20 l · 5 91785 g / m 2 dry. The pigment particles comprise at least 5 parts of the thermoplastic halogen-free polymer particles, the rest of the pigment being mostly inorganic pigment.

5

In this context, pigment particles are particles dispersed in the head together with a latex binder, which are bonded together by the binder in the finished coating.

The total amount of coating layer is at least 30 g / m 2, and most preferably it is between 30 and 65 g / m 2. In this case, it can be formed either exclusively in one step from the coating layer 15 2 applied to the base paper 1. However, as in Fig. 2, the coating can consist of the above-mentioned surface coating PP and the pre-coating layer EP applied to the base paper 1 before the surface coating. The amount of the surface coating PP can then vary between 20 and 40 g / m 2, and the amount of the precoating layer 20 EP is at least 5 g / m 2, preferably 10 to 25 g / m 2. The amount of latex binder in the precoat layer may be lower than in the surface coating PP and may then vary between 10 and 25 parts per 100 parts of solid particles of the precoat layer. The pre-coating layer may also contain particles of thermoplastic halogen-free polymer, but may not be required if the amount of such particles in the surface coating is large.

Figure 2 further illustrates in broken lines that the precoat layer EP can also consist of a layer applied in two different stages, denoted by EP1 and EP2. The composition of these layers is the same as mentioned above and their amount is such that the total amount of the precoating layer EP becomes the above.

91785 6 As the latex binder for the surface coating of the coating layer, all water-based solvent-free latexes which are generally used in wallpaper coatings are suitable. 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. Polyvinyl acetate-acrylate copolymer, ethylene-vinyl acetate copolymer (PVAC and EVAC) and full acrylate latexes are particularly suitable for use in the invention, and a styrene-butadiene latex which can easily change color over time is less suitable for use. Suitable inorganic pigments are, in turn, all pigments commonly used in wallpaper coatings, such as kaolins, calcium carbonates, calcium sulphate or gypsum, magnesium silicates or talc, aluminum silicates, titanium dioxide, aluminum hydroxide, barium sulphate, barium sulphate. . A mixture of magnesium silicate and calcium carbonate, which is particularly suitable, has proved to be a good mixture of inorganic mineral-based pigments. 25 for use in a coating paste for making a wallpaper according to the invention. The dispersibility of talc, i.e. magnesium silicate, in the latex dispersion can then be improved by means of calcium carbonate and special dispersibility-increasing wetting agents can be reduced, which would make the finished coating too hydrophilic. Used calcium carbonate? is then preferably ground and not precipitated.

As the thermoplastic halogen-free pigment particles 35, particles consisting of a polymer having a melting point of 100 to 250 ° C can be used.

; The heat used in the corrugation causes the thermoplastic particles to melt, the coating layer i 91785 7 becomes more easily deformable, and the particles create a permanent surface pattern when they solidify again.

The wallpaper obtained in this way is shown in Figure 3.

In practice, in the preparation of a coating paste, the particles formed by the thermoplastic polymer can be mixed with the other ingredients into the paste, whereby they are evenly distributed in the paste and the finished coating. In this case, they can be used either as ready-made aqueous dispersions or in powder form. Such materials are, for example, polystyrene, polypropylene, polyethylene, polyester. It is also possible to use some mixture thereof. Synthetic and asynthetic waxes composed of a thermoplastic polymer can also be used. Such wax dispersions are commonly available "hot-melt" dispersions, the particles of which form a pigment component of a thermoplastic halogen-free polymer in the coating. The above-mentioned compounds can also be partially or completely replaced by other thermoplastic compounds.

All latexes and pigments suitable for the above-mentioned surface coatings can also be used in the precoat layer.

In addition, the coating paste may, of course, contain flame retardants, resilient blowing agents, hardeners and optical brighteners commonly used in wallpaper coatings, as well as other excipients such as dispersants, defoamers and anti-foaming agents. per above solid particles.

δ 91785

As the base paper 1, any paper with suitable surface properties can be used. The basis weight of the base paper can be, for example, 90-120 g / m2. When using pre-coating layers, more mechanical pulp can be used on the surface to be coated than when using a single coating layer.

In the production of the wallpaper according to the invention, the coating layer can be applied by coating methods known per se, such as blade, air brush, rod and roll coating methods. In addition, it is possible to form the precoat layer EP already on a paper machine by some of the above-mentioned methods and the surface coating PP by some off-machine method, e.g. by air brush, blade, reverse roll, die or screen printing method.

The following are some recipes for preparing the coating layer of the wallpaper according to the invention. The amounts in the recipes are the amounts of dry matter.

Recipe l. New PVC replacement heat-shrinkable surface coating Intended use Chemical composition 1 Pigment Calcium carbonate 75.0 parts

Polymer Polyethylene 25.0 parts

Dispersant Polyacrylic 1 acid salt 0.3 parts

Viscosity regulator Acrylic ester 0.4 parts

Binder 1 PVAC acrylate latex 45.0 parts

Binder 2 Polyvinyl alcohol 5.0 parts

Hardener_Melaminformaldehyde 1 resin_0.6 parts - dry matter content 55 - 65%

- viscosity 50 - 300 mPa.s / 100 r / min / 20 ° C

- amount of coating 20 - 50 g / m2 dry I: 9 91765

Recipe 2. New PVC replacement heat-shrinkable surface coating (for airbrush coating) Intended use Chemical composition

Pigment 1 Magnesium 1 Iicate 30.0 parts

Pigment 2 Calcium carbonate 60.0 parts

Polymer Polystyrene dispersion 10.0 parts (Rhodcpas)

Dispersant Sodium salt of polycarboxylic acid 0.35 parts

Defoamer 0.1 parts of vegetable oil and fatty acid esters

Binder_EVAC-latex_55.0 parts - dry matter content 55 - 65%

- viscosity 50 - 300 mPa.s / 100 r / min / 20 ° C

- amount of coating 20 - 50 g / m2 dry

Recipe 3. New PVC heat-shrinkable surface coating (for blade, reverse roll, die and screen printing methods) Intended use Chemical composition

Pigment 1 Magnesium silicate 40.0 parts

Pigment 2 Calcium carbonate 20.0 parts

Pigment 3 Titanium dioxide 10.0 parts

Polymer Hot-melt dispersion (wax) 30.0 parts • Dispersant Polyacrylic acid salt 0.4 parts

Antifoam White oil icy 0.1 parts

Viscosity regulator Acrylic-based polymer dispersion 0.6 parts - "- Carboxymethylcellulose 0.4 parts

Binder_Akrvvlilateksi_60.0 parts - dry matter content 55 - 65%

- viscosity 600 - 4000 iriPa.s / 100 r / min / 20 ° C

- coating amount 30 - 50 g / m2 dry 10 91785

Recipe 4. So-called normal pre-coating (for blade coating) Intended use Chemical composition

Pigment Calcium carbonate 100.0 parts

Dispersant Polyacrylic acid salt 0.3 parts

Defoamer 0.1 parts of vegetable oil and fatty acid esters

Viscosity regulator Carboxymethylcellulose 0.3 parts

Acrylic ester 0.5 parts

Binder PVAC acrylate 12.0 parts

Hardener_Melaminformaldehyde hart-ai_0.4 parts - dry matter content of the applied coating 58 - 67%

- viscosity 600 - 1500 mPa.s / 100 r / min / 20 ° C

- amount of coating 5-25 g / m2 when dry

Recipe 5. The so-called normal pre-coating (for airbrush coating) Intended use Chemical composition

Pigment 1 Magnesium silicate 30.0 parts

Pigment 2 Calcium carbonate 60.0 parts

Pigment 3 Titanium dioxide 10.0 parts

Dispersant Ammonium salt of polycarboxylic acid 0.3 parts

Defoamer 0.1 parts of vegetable oil and fatty acid esters

Viscosity regulator Acrylic ester 0.3 parts

Binder EVAC dispersion 20.0 parts

Hardener_AnftKmium zirconium carhnate_0.6 parts - dry matter content 55 - 65%

- viscosity 50 - 300 mPa.s / 100 r / min / 20 ° C

- amount of coating 5-25 g / m2 when dry

In recipes 4 and 5, part of the pigment may be a thermoplastic halogen-free polymer such as in a topcoat.

li 11 91765

The table below shows the conceivable pre-coating and surface coating combinations when preparing the wallpaper according to the invention using one of the above-mentioned recipes.

Table Examples of pavement volumes run in different ways, the figures indicate the basis weight of the pavement in dry g / m2

Pre-Coatings (EP) Surface Coatings (EP) - blade - cloth brush - cloth brush - blade

Replacement (optional) - Reverse Roll tot.

condition - screen weight g / m2 - nozzle (optional)

EP1 EP2 EP

A 50 50 B 12 40 52 C 20 - 35 55 D 12 10 20 42 E 12 10 40 62

The wallpaper according to the invention has been found to have considerably better heat resistance compared to normal wallpaper with a PVC coating, for example the decrease in brightness in the experiments has been in the order of ten to 5% by percentage when it is several percent with a PVC coating. In addition, the wallpaper according to the invention burns less, and when it burns, it produces less visible smoke and harmful substances than PVC-coated wallpaper. In addition, the wallpaper according to the invention can be embossed, which is not possible with normal PVC-coated wallpapers. The wallpaper according to the invention, on the other hand, can be heat-shrunked just like PVC-coated wallpaper, which is not a feature of ordinary wallpaper containing an inorganic pigment and a latex binder. In addition, the wallpaper has a better ink absorption, i.e. it does not exhibit beading 5 during printing to the same extent as PVC-coated wallpapers. The print is also better.

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Claims (10)

The wallpaper, soin, comprises a latex binder and pigment containing coating material (2) present on the base paper (1) which has a coating (PP) containing at least 25 parts latex binder for 100 parts pigment particles and has an amount of at least 20 g / m2 in a dry state, the total amount of the coating layer being at least 30 g / m2, characterized in that the pigment particles of the coating contain at least 5 parts particles of a thermoplastic halogen-free polymer while the rest of the pigment is in most of the inorganic pigment known per se. . The loss according to claim 1, characterized in that the proportion of the thermoplastic, halogen-free polymer in the pigment particles is at least 10 parts, preferably more than 20 parts. The wallpaper according to claim 2, characterized in that a maximum of 60 parts are particles consisting of the halogen-free polymer and the remainder consists of the inorganic pigment. The wallpaper according to any one of claims 1-3, characterized in that the coating (PP) contains 40-65 parts of latex binder for 100 parts of solid particles. The wallpaper according to any one of claims 1-4, characterized in that the coating layer (2) comprises a pre-coating layer (EP) of between the coating (PP) and the base paper (1), which contains at least 8 parts, preferably 10-25 parts latex binder for 100 parts 35 pigment particles. 91785 The wallpaper according to claim 5, characterized in that the pre-coating layer (EP) consists of two layers distributed at different stages (EP1, EP2). The wallpaper according to claim 5 or 6, characterized in that the amount of the pre-coating layer (EP) is at least 5 g / m2, preferably 10-25 g / m2. The wallpaper according to any of the preceding claims, characterized in that the thermoplastic polymer in the coating or in the pre-coating layer or in the bed layers consists of polystyrene, polyacrylate, polyethylene, polypropylene or hot melt wax particles or of a mixture of some of these particles. 15 9. The loss according to any of the preceding claims, characterized in that the inorganic pigments of the coating (PP) comprise both magnesium silicate and calcium carbonate. 20 The loss according to claim 9, characterized in that the ratio of the amounts of magnesium silicate to calcium carbonate is 3: 1 to 1: 3. li