PL201227B1 - Decorative substrate paper and decorative paper - Google Patents

Abstract

Raw paper for making decorative laminates contains a pigment mixture comprising titanium dioxide (TiO2) and talc, where the talc has an average particle size (d50) of less than 3 mu m. An Independent claim is also included for decorative paper or films comprising the raw paper.

Description

(12) PATENT DESCRIPTION (19) PL (11) 201227 (13) B1 (21) Application number: 350718 ^{(51) Int.Cl.}

D21H 17/63 (2006.01) D21H 11/22 (2006.01) (22) Date of notification: 16.11.2001

The patent description was reprinted due to noticed errors (54)

Decorative backing paper and its use (30) Priority:

17.11.2000, DE, 10057294.4 (43) Application announced:

20.05.2002 BUP 11/02 (45) The following was announced about the grant of the patent:

31.03.2009 WUP 03/09 (73) The holder of the patent:

Technocell Dekor GmbH & Co. KG,

Osnabmck, DE (72) Inventor (s):

Hartmut Schulz, Wallenhorst, DE (74) Agent:

Zofia Sulima,

Sulima Grabowska Sierzputowska,

Patent and Trademark Office S.C.

⁽⁵⁷⁾ The invention relates to a decorative base paper for decorative coating materials, containing a pigment mixture containing titanium dioxide and talc, wherein the talc has a particle size distribution with a D50 of less than 2.0 µm, and the use of this base paper for the production of decorative paper or decorative sheet.

PL 201 227 B1

Description of the invention

The invention relates to a decorative base paper and its use.

Decorative coating materials, so-called decorative sheets or decorative paper (resin-impregnated paper) are preferably used for coating surfaces in furniture production and in interior design. Decorative sheets are printed or unprinted sheets of paper impregnated with a synthetic resin and optionally surface treated. Decorative sheets are glued to or connected to the base plate.

Depending on the type of impregnation process, a distinction is made between decorative sheets with a fully impregnated paper core and decorative sheets based on a pre-impregnate, in which the paper is only partially impregnated on the production line in the paper machine. Molded laminate materials (high pressure laminates) are laminates made by pressing together several layers of impregnated paper. Such formed laminate materials typically include a clear layer (top layer) that provides extremely high surface durability, a decorative paper impregnated with a synthetic resin, and one or more layers of phenolic resin impregnated kraft paper. Molded fiberboard and chipboard, as well as plywood, can be used as substrates for these materials.

In the case of laminates (low pressure laminates) produced in a short production cycle, decorative paper impregnated with synthetic resin is pressed directly onto a substrate, e.g. chipboard, under low pressure. The decorative paper used in the aforementioned coating materials is white or colored and may be with or without additional printing.

The so-called decorative base paper should meet special requirements, such as a high degree of opacity for better coverage of the base, uniformity of form and grammage for even absorption of the resin, high resistance to light, high purity and uniformity of color for good repeatability of the printed pattern, high strength in the wet state, ensuring a trouble-free impregnation process, adequate absorbency to ensure the required degree of resin saturation, and dry strength, which is important in rewinding operations in the paper machine and printing in a printing press.

The decorative backing paper is typically made from high whiteness kraft pulp, typically hardwood pulp, up to 45% pigments and fillers, and wet strength agents, retention aids and fixatives. Decorative backing paper differs from plain paper in that it contains many more fillers, and the manufacturing process does not use internal or surface sizing with common papermaking known sizing agents such as alkyl ketene dimers.

Opacity is one of the most important properties of decorative base paper. It characterizes the ability to cover the substrate.

The high opacity of the decorative base paper is also achieved by adding white pigments. Typically, titanium dioxide is used as the white pigment. This pigment provides high opacity and good brightness and whiteness of the decorative base paper. However, the disadvantage is the high cost of titanium dioxide.

Replacing some or all of the titanium dioxide with other white pigments adversely affects these properties. Opacity can only be achieved by increasing the pigment content. However, the pigment content cannot be increased indefinitely, as in this case physical properties such as pulp suspension retention, strength, lightfastness and resin absorption can be expected to be adversely affected.

There was therefore a need for a low-cost decorative paper with high opacity while reducing the titanium dioxide content.

The paper with the required properties was obtained thanks to the use of an appropriate pigment.

The present invention relates to a decorative base paper for decorative coating materials characterized in that it comprises a mixture of a pigment comprising titanium dioxide and talc, wherein the talc has a particle size distribution D50 of less than 2.0 .mu.m and a specific surface area of more than 30000 m ² / kg.

Preferably, the decorative base paper comprises talc in an amount of 0.1 - 25% by weight, based on the total pigment content.

Preferably, the decorative base paper comprises cationically modified cellulose fibers.

PL 201 227 B1

Preferably, the decorative base paper comprises cellulose fibers modified with glycidyl quaternary ammonium compounds.

The invention also relates to the use of a decorative base paper as defined above for the production of the décor paper or décor sheet.

The talc used according to the invention has a very narrow particle size distribution, the D50 value being less than 2 µm. This means that 50% by weight of the talc particles are less than 2 µm in diameter.

Surface area of the talc used in the invention is greater than 30000 m ² / kg or, preferably higher than 40000 m ² / kg. On the other hand, the specific surface area of traditional types of talc is 8,000 - 16,000 m ² / kg. The specific surface was determined according to DIN 66126.

The amount of talc in the pigment mixture is preferably 0.1-25 wt.%, Based on the total pigment content.

The titanium dioxide contained in the pigment mixture used in the decorative base paper of the invention may be the titanium dioxide conventionally used in decorative paper. Such titanium oxides are commercially available and may be of the rutile or anatase type. Rutile titanium oxides are particularly preferred.

Other fillers such as zinc sulfide, calcium carbonate, kaolin or mixtures thereof can be used.

The amount of filler in the decorative base paper may be up to 55% by weight, in particular 11-50% by weight or 20-45% by weight, based on the weight of the paper. The basis weight of the decorative base paper according to the invention may be 30 - 300 g / m ^2, and typically is 40 - 200 g / m ^2. The basis weight is selected depending on the specific application.

Coniferous pulp (long-fiber pulp) or hardwood pulp (short-fiber pulp) can be used as the pulp for producing the decorative base paper according to the invention. Cotton fibers or mixtures of the above-mentioned types of cellulose can also be used. For example, a mixture of coniferous pulp and hardwood pulp in a ratio of 10:90 to 90:10 or in a ratio of 30:70 to 70:30 is particularly preferred. The pulp may exhibit a fineness of 20-60 ° SR according to Schopper-Riegler.

The pulp preferably comprises cationically modified cellulosic fibers in an amount of at least 5% by weight, based on the total pulp. A content of cationically modified cellulose in the total pulp of 10-50% by weight, in particular 10-20% by weight, has been found to be particularly advantageous.

Cationically modified pulps are known e.g. from Das Papier, Vol. 12 (1980), pp. 575-579.

In particular, the cationically modified cellulose contained in the furnish has an effective cationic charge of 20 - 300 mmoles / kg of pulp, determined according to internal method No. 4 of the Technical University of Darmstadt. Pulp fibers with a charge density of 30-200 mmoles / kg, in particular 30-100 mmoles / kg, are preferred. The term "effective cationic charge" means the charge density measured against the charge density of the non-cationized pulp. The charge density depends on the quality of the cationic agent used. The amount of the cationizing agent may be 0.005-200 g / kg of the pulp.

The pulp fibers can be cationically modified by reacting the fibers with epichlorohydrin resin and a tertiary amine, or by reaction with quaternary ammonium chlorides such as chlorohydroxypropyltrimethylammonium chloride or glycidyl trimethylammonium chloride.

Cationically modified pulp fibers are preferably used by addition of glycidyl-functional quaternary ammonium compounds with hydroxyl groups of cellulose.

The decorative base paper of the invention may contain wet strength agents such as polyamide / polyamine epichlorohydrin resin, cationic polyacrylates, modified melamine formaldehyde resin or cationized starches. They are added to the pulp suspension. Retention aids and other substances such as colored organic and inorganic pigments, dyes, optical brighteners and dispersants may also be added.

The decorative base paper of the invention can be produced on a Fourdrinier or a Yankee papermaking machine. For this purpose, the pulp can be ground to a degree of comminution of 30 - 45 ° SR with a pulp content of 2 - 4% by weight. Fillers such as titanium dioxide and talc, and wet strength agents are added

In a mixing vat, it is thoroughly mixed with the pulp. The resulting thick pulp is diluted to a pulp content of about 1% by weight. If desired, other additives such as retention aids, antifoams, aluminum sulfate and the other additives mentioned above are added. This diluted pulp is passed through the headbox of the papermaking machine and directed to the mesh section. A non-woven fabric is formed, from which, after dewatering, a decorative base paper is obtained, which is then dried.

To produce the decorative paper, the decorative base paper is impregnated with the customary synthetic resin dispersions intended for this purpose. Such synthetic resin dispersions include, for example, those based on polyacrylates or polymethacrylates, polyvinyl acetate, polyvinyl chloride or synthetic resin solutions based on phenol-formaldehyde precondensates, urea-formaldehyde precondensates or melamine-formaldehyde precondensates, or compatible mixtures thereof.

The impregnation can also be performed on a size press on a paper machine. Decorative base paper can be impregnated in such a way that the paper is not completely impregnated. Such decorative paper is also referred to as a pre-impregnate. In this case, the amount of resin incorporated into the decorative base paper by impregnation is 25-30% by weight, based on the weight of the paper.

After drying, the impregnated paper can also be coated or printed and then applied to a substrate such as a wood board. Coated and optionally printed products are generally referred to as decorative sheets.

The following examples illustrate the invention. The percentages by weight are based on the amount of pulp, unless otherwise stated.

P r z k ł a d 1

Pulp containing 70 wt. % eucalyptus pulp and 30 wt. % softwood kraft pulp, blended with 0.6 wt. % of epichlorohydrin resin as a wet strength agent, 0.11 wt. % of a retention enhancer and 0.03 wt. antifoam to form a base mixture. The last three percentages are based on the amount of pulp. The pH of this mixture was adjusted to 6.5 with aluminum sulfate. This mixture was then mixed with the pigment mixture, 55.8 wt.%. % of titanium dioxide and 5.2 wt. talcum powder. A decorative paper with a basis weight of 105 g / m ² was produced on a Fourdrinier papermaking machine. The content of titanium dioxide was 33.5 g / m ² (31.9 wt.%) And the content of talc of 3.1 g / m ² (2.95 wt.%). Talc is used having particle size distribution with a D50 of 1.9 .mu.m and a specific surface area of 44300 m ² / kg.

P r z k ł a d 2

A pigment mixture of 50.3 wt.% Was added to the base mixture of Example 1. % of titanium dioxide and 14.7 wt. talcum powder. Decorative paper with a basis weight of 105 g / m ² was produced on a Fourdrinier paper machine. The content of titanium dioxide was 30.2 g / m ² (28.8 wt.%), And the content of talc 8.8 g / m ² (8.4 wt.%). Talc is used having particle size distribution with a D50 of 1.9 .mu.m and a specific surface area of 44300 m ² / kg.

P r z k ł a d 3

A pigment mixture of 64.5 wt.% Was added to the base mixture of Example 1. % of titanium dioxide and 3.3 wt. talcum powder. Decorative paper with a basis weight of 105 g / m ² was produced on a Fourdrinier paper machine. The content of titanium dioxide was 38.7 g / m ² (36.5 wt.%), And the content of talc 2.0 g / m ² (1.9 wt.%). Talc is used having particle size distribution with a D50 of 1.9 .mu.m and a specific surface area of 44300 m ² / kg.

P r z k ł a d 4

A pigment mixture of 53.9 wt.% Was added to the base mixture of Example 1. % of titanium dioxide and 11.3 wt. talcum powder. Decorative paper with a basis weight of 105 g / m ² was produced on a Fourdrinier paper machine. Titanium dioxide content of 32.3 g / m ² (30.8 wt.%), And the content of talc 6.8 g / m ² (6.5 wt.%). Talc is used having particle size distribution with a D50 of 1.5 .mu.m and a specific surface area of 47100 m ² / kg.

P r z k ł a d 5 (comparative)

In this example, only 62 wt.% Was added to the base mixture of example 1. titanium dioxide dispersion. Decorative paper with a basis weight of 120 g / m ² and a titanium dioxide content of 37.2 g / m ² (31 wt.%) Was produced on a Fourdrinier paper machine.

PL 201 227 B1

P r z k ł a d 6 (comparative)

A pigment mixture of 50.8 wt.% Was added to the base mixture of Example 1. % of titanium dioxide and 14.4 wt. talcum powder. Decorative paper with a basis weight of 105 g / m ² was produced on a Fourdrinier paper machine. The titanium dioxide content was 30.5 g / m ² (29% by weight) and the talc content

8.7 g / m ² (8.3 wt.%). Talc is used having particle size distribution with a D50 of 3.7 .mu.m and a specific surface area of 8600 m ² / kg.

The opacity of the paper samples of Examples 1-4 and Examples 5 and 6 (comparative) was determined according to DIN 53146 using an ACE color measuring instrument with Data Color. The titanium dioxide content of the decorative base paper was determined according to DIN 54370. The results are given in the table below.

T a b e l a

A sample Opacity (%) Talc content based on total pigments (%) Talc content (g / m ² ) 1 92.68 8.5 3.1 2 92.55 22.6 8.8 3 92.61 4.9 2.0 4 92.62 17.3 6.8 5 92.71 0.0 0.0 6 90.28 22.2 8.7

The results of the opacity measurements show that high opacity can be achieved with the talc used according to the invention, even with a significantly reduced titanium dioxide content.

Claims (5)

Patent claims 1. A decorative base paper for decorative coating materials characterized in that it comprises a mixture of a pigment comprising titanium dioxide and talc, wherein the talc has a particle size distribution D50 of less than 2.0 .mu.m and a specific surface area of more than 30000 m ² / kg. 2. A decorative base paper according to claim 1. The process according to claim 1, characterized in that the talc is present in an amount of 0.1 - 25% by weight, based on the total pigment content. 3. A decorative base paper according to claim 1. The process of claim 1 or 2, characterized in that it contains cationically modified cellulose fibers. 4. A decorative base paper according to claim 1. The process of claim 3, characterized in that it contains cellulose fibers modified with quaternary ammonium compounds with a glycidyl group. 5. Use of a decorative base paper as defined in claim 1. 1 - 4 for making decorative paper or decorative sheet.