DE19503745C2 - Printing paper for film production - Google Patents

Description

The invention relates to a printing paper for film production.

Here films are to be understood as surface coating materials that are used for loading layering of surfaces such as wall panels, furniture (drawers, Cabinet back panels) or game boards can be used.

They usually consist of a "normal" paper that is in one color or multi-color printing process can be printed as desired, and a varnish layer made of, for example, polyester, acrylate, silicic acid ester or polyurethane. You who with the help of adhesives in a so-called short cycle method (short cycle ver press) connected to the surface to be coated. A disadvantage of the use of the paper mentioned above is the insufficient print quality of the on the paper brought patterns, formation of fiber dust during the printing process and the Ein penetrate the lacquer applied in the further process into the inside of the paper (bad lacquer level) and the associated loss of opacity.

The use of conventional preimpregs is also known in film production decorative paper-based grades. The decorative paper is made of cellulose fibers, titanium dioxide (up to 40% by weight) and wet strength paper consisting of a melamine / form dehydrated or urea / formaldehyde resin is pre-impregnated. In connection with the The use of formaldehyde-containing impregnating resins is an ecological point of view in need of improvement.

The object of the present invention is therefore a printing paper for film production propose that does not have the disadvantages mentioned above.

The object is achieved in that the printing paper is on at least one side with a film-forming substance selected from that of starch, a modified starch ke, carboxymethyl cellulose, polyvinyl alcohol and galactomannan existing group, contains coated raw paper, the pulp fibers of which have a freeness of 38 to 65 ° SR (determination of the degree of grinding according to Schopper-Riegler, Zellcheming leaflet V / 7/61).

In a special embodiment of the invention, the degree of grinding is 40 to 55 ° SR.

The pulp can be a long fiber (softwood pulp) or short fiber pulp (Hardwood pulp). However, a mixture of long and short-fiber pulps, the proportion of long-fiber pulp being 20 to 50% by weight wearing.

Secondary cellulose fibers from recycled raw materials can also be used.

Such compounds as, in particular, are suitable as film-forming substances Carboxymethyl cellulose, polyvinyl alcohol, various starches or modified starches ken or starch derivatives, as well as galactomannans or mixtures of these compounds Butadiene / styrene / acrylate-based latices can also be used for this will.

Etherified, esterified or oxidized starches are particularly preferred.  

The film-forming substance can be cross-linked. As crosslinking agents, all can be knew crosslinking agents such as glyoxal, chromium and zirconium salts, aziridines or Compounds containing epoxy groups can be used.

The amount of crosslinking agent is 0.1 to 10% by weight, based on the amount of film-forming substance.

The base paper is coated with the film-forming substance from aqueous Dispersion in a size press. But other order units can also do this be turned. The application amount is 0.1 to 6 g / m², but preferably 0.5 to 2 g / m², based on the dry layer.

The pulp suspension becomes a sizing agent with a hydrophobic effect, such as alkyl ketendimer admixed by adding auxiliaries on the surface of the fibers is deposited. Such an aid is here, for example, the same as wet cationic polyamide / polyamine-epichlorohydrin resin. But also other cationic substances such as cationic polyacrylamides or cationized starches as well as fillers such as CaCO₃ can be used.

The pulp suspension can also use other conventional sizing agents and auxiliaries be added.

The basis weight of the base paper is preferably 60 to 140 g / m².  

With the printing paper according to the invention can in comparison to the from the prior art The following advantages can be achieved with known printing papers:

• - A better surface, which leads to better print quality and reduction of dust (Fiber dust) during the printing process.
• - an optimal paint level, d. H. the on the surface of the printed paper brought varnish remains on the surface and does not penetrate the inside of the paper (better opacity).
• - Environmentally friendly - impregnation resins containing formaldehyde can be dispensed with will.
• - Cost-effective production, since the processing step of impregnation is switched on saves and the use of expensive TiO₂ can be dispensed with.

The present invention can be explained in more detail using the following examples:

example 1

A mixture of 75% by weight hardwood sulfate pulp and 25% by weight softwood sulfate pulp was milled at a consistency of 4% to a freeness of 40 ° SR len. The following substances were added to the pulp suspension and from them approx. 80 g / m² heavy base paper made:

The base paper described above was made with those listed in the following table aqueous dispersions coated in-line in the size press.

Example 2

A mixture of 50% by weight hardwood sulfate pulp and 50% by weight softwood sulfate pulp was milled at a consistency of 4% to a freeness of 50 ° SR len. Substances as in Example 1 were added to the pulp suspension and an approx. 100 g / m² heavy base paper, which is then coated with an aqueous dispersion was deleted according to Example 1a.

Comparative Example V

The conventional printing paper served as a comparison.

Examination of the papers produced according to the examples and the comparative example

The following test methods were used for the evaluation:

Gap resistance

This property was determined in accordance with TAPPI RC 308 using a commercially available Scott Bond gap strength tester. The figures in the table below are mean values from 5 individual measurements. The measured values are given in m · kg · 10 ^-3 .

Smoothness after Bekk

The smoothness determination was carried out according to TAPPI 479 sm 48 with a commercially available smoothness tester carried out. The measured values are given in Bekk seconds. They are each Average values from 3 measurements.

opacity

The opacity is a measure of the translucency of the paper. It was on Paper test samples 8 × 8 cm measured with the Elrepho colorimeter.

Breakthrough time

For this purpose, test strips (8 × 6 cm) were placed in a top coat liquid (foil top coat Plantag Chemie GmbH No. 368013).

The breakthrough time is measured from the time the paper is placed in the Liquid until the entire surface of the paper with the Liquid is covered.

The penetration time is a measure of the so-called paint level. The higher the values the better the paint level.

The test results are summarized in Table 1.  

Table 1

Test results

As can be seen from the table, the papers produced according to the invention, ver equal to conventional printing paper, a better surface and a significantly higher breakthrough time here. This improves the printability of the papers and a better paint level achieved.

The papers according to the invention also have better splitting strength Values.

Claims (5)

1. Printing paper for film production, characterized in that it contains at least one side with a film-forming substance, selected from the group consisting of starch, a modified starch, carboxymethyl cellulose, polyvinyl alcohol and galactomannans, coated raw paper, the pulp fibers of which have a freeness of 38 to 65 ° SR. 2. Printing paper according to claim 1, characterized in that the degree of grinding 40 to Is 55 ° SR. 3. Printing paper according to claim 1 and 2, characterized in that the film-forming Substance is a starch ether, a starch ester or an oxidized starch. 4. Printing paper according to claim 1 to 3, characterized in that the order amount of the film-forming substance is 0.1 to 6 g / m², in particular 0.5 to 2 g / m². 5. Printing paper according to claim 1 to 4, characterized in that the film-forming Substance is networked.