METHOD FOR PRODUCING A WAX-FREE TWIST-WRAPPING PAPER

Abstract

A method for producing a twist-wrap paper is shown, wherein a first barrier coating composition is applied to one side of a twist-wrap base paper, wherein the first barrier coating composition comprises water and film-forming starch in an amount of at least 65.0% and at most 85.0%, binder in an amount of at least 10.0% and at most 30.0%, and crosslinking agent in an amount of at least 1.0% and at most 5.0%. A second barrier coating composition is applied to the dried first barrier coating composition, wherein the second barrier coating composition comprises water and film-forming starch in an amount of at least 75.0% and at most 95.0%, binder in an amount of at least 1.0% and at most 5.0%, and kaolin in an amount of at least 4.0% and at most 15.0%.In the dried state, the mass of the first barrier coating composition remaining on the twist wrap base paper is at least 0.5 g / m2 and at most 3.0 g / m2, and the remaining mass of the second barrier coating composition is at least 1.0 g / m2 and at most 5.0 g / m2, and the finished twist wrap paper has a basis weight of at least 20 g / m2 and at most 65 g / m2, wherein less than 1.0% of the mass of the twist wrap paper is formed by a wax coating.

Claims

[1] A process for producing a twist-wrap paper, comprising the following steps AE: A - Providing a twist wrap base paper B - Applying a first barrier coating composition to one side of the twist wrap base paper, wherein the first barrier coating composition comprises water and - film-forming starch in a quantity of at least 65.0% and at most 85.0%, - Binder in an amount of at least 10.0% and at most 30.0%, and - crosslinking agent in an amount of at least 1.0% and at most 5.0%, in each case based on the mass of solids in the first barrier coating composition, C - Drying the first barrier coating composition, D - Applying a second barrier coating composition to the dried first barrier coating composition from step C, wherein the second barrier coating composition comprises water and - film-forming starch in an amount of at least 75.0% and at most 95.0%, - Binder in a quantity of at least 1.0% and at most 5.0%, and - kaolin in an amount of at least 4.0% and at most 15.0%, in each case based on the mass of solids in the second barrier coating composition, E - drying the second barrier coating composition, wherein after drying in step E, the mass of the first barrier coating composition remaining on the twist-wrap base paper, based on the area to which the first barrier coating composition was applied in step B, at least 0.5 g / m 2 and a maximum of 3.0 g / m 2 is, and after drying in step E, the mass of the second barrier coating composition remaining on the twist-wrap base paper based on the area, to which the second barrier coating composition was applied in step D, at least 1.0 g / m 2 and a maximum of 5.0 g / m 2 amounts, and wherein the twist wrap paper after step E has a basis weight of at least 20 g / m 2 and a maximum of 65 g / m 2 and wherein less than 1.0% of the mass of the twist wrap paper is formed by a wax coating. [2] The method of claim 1, wherein the first and second barrier coating compositions are applied to the top surface of the twist wrap base paper. [3] A method according to claim 1 or 2, wherein the twist-wrap base paper in step A comprises cellulose fibers, wherein the cellulose fibers are obtained from coniferous woods, in particular spruce, pine or fir; from deciduous woods, in particular birch, beech or eucalyptus; or from other plants, in particular hemp, flax, jute, ramie, kenaf, kapok, coconut, abaca, sisal, bamboo, cotton or esparto grass, wherein the cellulose fibers are preferably a mixture of cellulose fibers from various of these sources. [4] Process according to one of the preceding claims, in which the twist-wrap base paper in step A contains fillers or pigments, the mass of the fillers or pigments in total not being more than 15.0% of the mass of the twist-wrap base paper, preferably not being more than 10.0% of the mass of the twist-wrap base paper. [5] Process according to claim 4, wherein the fillers or pigments are formed by calcium carbonate, magnesium carbonate, magnesium hydroxide, magnesium oxide, kaolin, titanium dioxide or mixtures thereof. [6] Method according to one of the preceding claims, wherein the provision of the twist wrap base paper in step A comprises producing the twist wrap base paper in a paper machine, preferably in a Fourdrinier paper machine. [7] A process according to any one of the preceding claims, wherein the application of the first barrier coating composition in step B is carried out in a film press of a paper machine, a bar coater, a curtain coater, a jet coater or a printing device. [8] A process according to any one of the preceding claims, wherein the first barrier coating composition in step B is applied to at least 70%, preferably to at least 90% of the area of one side of the twist wrap base paper. [9] A process according to any one of the preceding claims, wherein the drying in step C is carried out by contact with a heated surface, by contact with hot air, by infrared radiation or by microwave radiation. [10] A process according to any one of the preceding claims, wherein the application of the second barrier coating composition in step D is carried out in a film press of a paper machine, a bar coater, a curtain coater, a jet coater or a printing device. [11] A process according to any one of the preceding claims, wherein the second barrier coating composition is applied in step D to at least 70%, preferably to at least 90% of the area of one side of the twist-wrap base paper so as to be applied at least partially, but not necessarily directly, to the first barrier coating. [12] Method according to one of the preceding claims, in which exactly two barrier coating compositions are applied, wherein the two barrier coating compositions are preferably applied directly to one another, with drying in step C as an intermediate step. [13] A method according to any one of the preceding claims, wherein the drying in step E is carried out by contact with a heated surface, by contact with hot air, by infrared radiation or by microwave radiation. [14] A process according to any one of the preceding claims, wherein the first barrier coating composition comprises the film-forming starch in an amount of at least 67.0% and at most 83.0%, preferably in an amount of at least 70.0% and at most 80.0%, in each case based on the mass of solids in the first barrier coating composition. [15] A process according to any one of the preceding claims, wherein the first barrier coating composition comprises the binder in an amount of at least 12.0% and at most 28.0%, preferably in an amount of at least 15.0% and at most 25.0%, in each case based on the mass of solids in the first barrier coating composition. [16] A process according to any one of the preceding claims, wherein the binder in the first and / or second barrier coating composition is or comprises a styrene-butadiene copolymer, a styrene-acrylate copolymer or a mixture thereof, preferably a styrene-1,3 butadiene latex. [17] A process according to any one of the preceding claims, wherein the first barrier coating composition comprises the crosslinking agent in an amount of at least 1.5% and at most 4.5%, preferably in an amount of at least 2.0% and at most 4.0%, in each case based on the mass of solids in the first barrier coating composition. [18] A process according to any one of the preceding claims, wherein the crosslinking agent comprises glyoxal or potassium zirconium carbonate. [19] A process according to any one of the preceding claims, wherein the first barrier coating composition has a solids content of at least 5.0% and at most 15.0%, preferably of at least 8.0% and at most 13.0%, in each case based on the mass of the first barrier coating composition. [20] A process according to any one of the preceding claims, wherein the first barrier coating composition has a pH of at least 8 and at most 10. [21] A process according to any one of the preceding claims, wherein the second barrier coating composition comprises the film-forming starch in an amount of at least 78.0% and at most 92.0%, preferably at least 83.0% and at most 90.0%, in each case based on the mass of solids in the second barrier coating composition. [22] A process according to any one of the preceding claims, wherein the second barrier coating composition comprises the binder in an amount of at least 1.5% and at most 4.5%, preferably at least 2.0% and at most 4.0%, in each case based on the mass of solids in the second barrier coating composition. [23] A process according to any one of the preceding claims, wherein the second barrier coating composition comprises the kaolin in an amount of at least 6.0% and at most 13.0%, preferably at least 7.0% and at most 11.0%, in each case based on the mass of solids in the second barrier coating composition. [24] A process according to any one of the preceding claims, wherein the kaolin is in the form of particles and has a particle size distribution such that 90% of the total particle volume is formed by particles having a size (D 90) of less than 3.0 µm, preferably less than 2.5 µm and particularly preferably less than 2.0 µm. [25] A process according to any one of the preceding claims, wherein the second barrier coating composition has a solids content of at least 10.0% and at most 20.0%, preferably of at least 12.0% and at most 18.0%, in each case based on the mass of the second barrier coating composition. [26] A process according to any one of the preceding claims, wherein, after drying in step E, the mass of the first barrier coating composition remaining on the twist-wrap base paper, based on the area to which the first barrier coating composition was applied in step B, is at least 0.6 g / m 2 and a maximum of 1.8 g / m 2 , preferably at least 0.8 g / m 2 and a maximum of 1.5 g / m 2 amounts. [27] A process according to any one of the preceding claims, wherein, after drying in step E, the mass of the second barrier coating composition remaining on the twist wrap base paper, based on the area to which the second barrier coating composition was applied in step D, is at least 1.2 g / m 2 and a maximum of 2.7 g / m 2 , preferably at least 1.4 g / m 2 and a maximum of 2.5 g / m 2 amounts. [28] A method according to any one of the preceding claims, wherein the basis weight of the twist wrap paper after step E is at least 25 g / m 2 and a maximum of 60 g / m 2 , preferably at least 33 g / m 2 and a maximum of 55 g / m 2 amounts. [29] Method according to one of the preceding claims, wherein the thickness of the twist wrap paper after step E is at least 30 µm and at most 70 µm, preferably at least 35 µm and at most 60 µm. [30] Method according to one of the preceding claims, wherein the Bendtsen air permeability of the twist wrap paper after step E is at most 10 ml / min, preferably at most 7 ml / min. [31] A process according to any one of the preceding claims, wherein the kit level, determined according to TAPPI method T 559 cm-22, of the side of the twist wrap paper after step E to which the barrier coating compositions were applied in steps B and D, respectively, is at least 7, preferably at least 8 and particularly preferably at least 9 in an area in which the barrier coating compositions were applied. [32] A method according to any one of the preceding claims, wherein the twist wrap paper according to step E does not comprise a wax coating, or the mass of a wax coating is less than 0.5%, preferably less than 0.1%, of the mass of the twist wrap paper. [33] Twist-wrap paper comprising a twist-wrap base paper and a barrier layer, wherein the barrier layer is applied to one side of the twist-wrap base paper and has a basis weight of at least 1.5 g / m 2 and a maximum of 8.0 g / m 2 based on the area to which the barrier layer is actually applied, and wherein the barrier layer comprises the following components: - film-forming starch in a quantity of at least 65.0% and at most 93.0%, - Binder in a quantity of at least 4.0% and at most 16.0%, - Kaolin in a quantity of at least 2.0% and at most 8.0%, and - cross-linking agent in an amount of at least 0.3% and at most 3.0%, each based on the mass of the barrier layer, and wherein the barrier layer comprises a first and a second coating region arranged one above the other such that the first coating region is closer to the twist-wrap base paper than the second coating region, wherein the concentration of kaolin in the second coating region is higher than in the first coating region, and wherein the twist wrap paper has a basis weight of at least 20 g / m 2 and a maximum of 65 g / m 2 and less than 1.0% of the mass of the twist wrap paper is formed by a wax coating. [34] Twist-wrap paper according to claim 33, obtainable by a process according to any one of claims 1 to 32. [35] Twist wrapping paper according to claim 33 or 34, wherein the first coating area - a film-forming starch in a quantity of at least 65.0% and at most 85.0%, - a binder in a quantity of at least 10.0% and at most 30.0%, and - a crosslinking agent in an amount of at least 1.0% and at most 5.0%, in each case based on the mass of the first coating area, and the mass per unit area of the first coating area, based on the area on which the first coating area is located, is at least 0.5 g / m 2 and a maximum of 3.0 g / m 2 is, and wherein the second coating area - a film-forming starch in a quantity of at least 75.0% and at most 95.0%, - a binder in a quantity of at least 1.0% and at most 5.0%, and - kaolin in an amount of at least 4.0% and at most 15.0%, in each case based on the mass of the second coating area, and the mass per unit area of the second coating area, based on the area on which the second coating area is located, is at least 1.0 g / m 2 and a maximum of 5.0 g / m 2 amounts. [36] Twist wrapping paper according to one of claims 33 to 35, wherein the first coating area is arranged directly on the second coating area. [37] Twist-wrap paper according to one of claims 33 to 36, wherein the basis weight of the barrier layer, based on the area to which the barrier layer is applied, is at least 1.5 g / m 2 and a maximum of 8.0 g / m 2 , preferably at least 2.0 g / m 2 and a maximum of 7.0 g / m 2 amounts. [38] Twist-wrap paper according to one of claims 33 to 37, in which at least 70.0% and at most 90.0%, preferably at least 75.0% and at most 85.0% of the mass of the barrier layer is formed by the film-forming starch. [39] Twist-wrap paper according to one of claims 33 to 38, in which at least 5.0% and at most 15.0%, preferably at least 7.0% and at most 13.0% of the mass of the barrier layer is formed by the binder. [40] Twist-wrap paper according to one of claims 33 to 39, in which at least 3.0% and at most 7.0%, preferably at least 4.0% and at most 6.5% of the mass of the barrier layer is formed by kaolin. [41] Twist-wrap paper according to one of claims 33 to 40, in which at least 0.5% and at most 2.5%, preferably at least 0.7% and at most 2.0% of the mass of the barrier layer is formed by the crosslinking agent. [42] Twist wrapping paper according to one of claims 33 to 41, the basis weight of which is at least 25 g / m 2 and a maximum of 60 g / m 2 , preferably at least 33 g / m 2 and a maximum of 55 g / m 2 amounts. [43] Twist-wrap paper according to one of claims 33 to 42, the thickness of which is at least 30 µm and at most 70 µm, preferably at least 35 µm and at most 60 µm. [44] Twist-wrap paper according to one of claims 33 to 43, the air permeability of which according to Bendtsen is at most 10 ml / min, preferably at most 7 ml / min. [45] Twist wrap paper according to one of claims 33 to 44, wherein the kit level of the side of the twist wrap paper on which the barrier layer is located, determined according to the TAPPI method T 559 cm-22, is at least 7, preferably at least 8 and particularly preferably at least 9 in a region in which the barrier layer is located. [46] Twist-wrap paper according to any one of claims 33 to 45, which does not comprise a wax coating, or in which the mass of a wax coating is less than 0.5%, preferably less than 0.1%, of the mass of the twist-wrap paper.