RECYCLABLE BARRIER PAPER

Abstract

A barrier paper having a paper substrate having a front side and a back side opposite the front side, and a barrier layer disposed to the front side of the paper substrate. The barrier layer has of a polymeric binder and a wax based on a vegetable oil, the use of a barrier paper as wrapping paper, lining paper, paper for inner-bag packaging, interleaving paper and/or release paper for foods, and also to a method for producing a barrier paper.

Claims

1.-16. (canceled)

17. A barrier paper comprising: a paper substrate having a front side and a back side opposite the front side; and a barrier layer disposed on the front side and/or back side of the paper substrate, wherein the barrier layer comprises at least a polymeric binder and a wax based on a vegetable oil.

18. The barrier paper as claimed in claim 17, wherein the wax based on a vegetable oil is a wax based on an oil selected from one or more of palm oil, coconut oil, poppyseed oil, olive oil, linseed oil, soybean oil, sunflower oil, safflower oil, and rapeseed oil.

19. The barrier paper as claimed in claim 17, wherein the wax based on a vegetable oil is a wax based on a soybean oil.

20. The barrier paper as claimed in claim 17, wherein a mass fraction of the wax in the barrier layer is at least one of: 6 to 98% based on a total mass of the barrier layer, 20 to 90% based on the total mass of the barrier layer, and 50 to 89%, based on the total mass of the barrier layer.

21. The barrier paper as claimed in claim 17, wherein a mass fraction of the wax in the barrier layer is 20 to 78%.

22. The barrier paper as claimed in claim 17, wherein the wax has a melting point of above at least one of 40 C., 50 C., and 60 C.

23. The barrier paper as claimed in claim 17, wherein the polymeric binder is a crosslinked or noncrosslinked binder selected from the group consisting of starch, polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, ethylene-vinyl alcohol copolymer, a combination of polyvinyl alcohol and ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, silanol group-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, acrylate copolymer, modified polyethylene glycol, unmodified polyethylene glycol, -isodecyl--hydroxy-poly(oxy-1,2-ethanediyl), styrene-butadiene latex, styrene-acrylate polymers, and mixtures thereof.

24. The barrier paper as claimed in claim 17, wherein the polymeric binder comprises one or more styrene-acrylate polymers.

25. The barrier paper as claimed in claim 24, wherein the acrylate copolymer is a copolymer prepared using two or more monomers selected from the group consisting of methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, and styrene.

26. The barrier paper as claimed in claim 17, wherein a mass fraction of the polymeric binder in the barrier layer is at least one of: 94 to 2% based on a total mass of the barrier layer, 80 to 10% based on the total mass of the barrier layer, and 50 to 11% based on the total mass of the barrier layer.

27. The barrier paper as claimed in claim 17, wherein the barrier layer further comprises a wax based on saturated hydrocarbons.

28. The barrier paper as claimed in claim 27, wherein the wax based on saturated hydrocarbons has a melting point of above at least one of 40 C., 50 C., and 60 C.

29. The barrier paper as claimed in claim 27, wherein the wax based on saturated hydrocarbons comprises at least one alkane selected from the group consisting of heneicosane, docosane, tricosane, tetracosane, pentacosane, hexacosane, heptacosane, octacosane, nonacosane, triacontane, hentriacontane, dotriacontane, tritriacontane, tetratriacontane, pentatriacontane, hexatriacontane, heptatriacontane, octatriacontane, and nonatriacontane.

30. The barrier paper as claimed in claim 17, further comprising: an interlayer disposed between the paper substrate and the barrier layer.

31. The barrier paper as claimed in claim 17, wherein the barrier paper is configured as one or more of wrapping paper, lining paper, interleaving paper and/or release paper for foods, for wrapping, lining, interleaving and/or separating of bakery products, fried and/or deep-fried products, snack products, sandwiches, bread, burgers, meat products, fish products, sausage products, and/or cheese.

32. A method for producing a barrier paper, comprising: (i) one of producing and providing a paper substrate; (ii) one of producing and providing a barrier coat comprising a wax emulsion, wherein the wax is based on a vegetable oil; and (iii) applying the barrier coat to one side of the paper substrate and subsequently drying the barrier coat, to provide a barrier layer.

33. The method for producing a barrier paper of claim 32, further comprising: (iv) disposing an interlayer between the paper substrate and the barrier layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0108] Further embodiments are apparent from the examples and working examples that are elucidated in more detail by means of the figures. In these figures:

[0109] FIG. 1 is a layer construction of barrier paper;

[0110] FIG. 2 is a layer construction of barrier paper;

[0111] FIG. 3 is a layer construction of barrier paper; and

[0112] FIG. 4 is a layer construction of barrier paper.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0113] FIG. 1 shows a barrier paper 10 that consists of a paper substrate 11 and a barrier layer 12. The paper substrate has a front side and a back side opposite the front side, and disposed on the front side of the paper substrate 11 is a barrier layer 12, which consists of a polymeric binder and a wax based on a vegetable oil.

[0114] FIG. 2 shows a barrier paper 10 that consists of a paper substrate 11, an interlayer 13, and a barrier layer 12. The paper substrate has a front side and a back side opposite the front side, and disposed on the front side of the paper substrate 11 is the interlayer 13. Disposed on the interlayer 13 in turn is the barrier layer 12, which consists of a polymeric binder and a wax based on a vegetable oil. The interlayer 13 preferably comprises a pigment and a binder.

[0115] FIG. 3 shows a barrier paper 10 that consists of a paper substrate 11 and two barrier layers 12. The paper substrate has a front side and a back side opposite the front side, and disposed on each of the front side and the back side of the paper substrate 11 is a respective barrier layer 12, which consists of a polymeric binder and a wax based on a vegetable oil.

[0116] FIG. 4 shows a barrier paper 10 that consists of a paper substrate 11, two interlayers 13, and two barrier layers 12. The paper substrate has a front side and a back side opposite the front side, and, disposed on each of the front side and the back side of the paper substrate 11, there is a respective interlayer 13. Disposed on each of the interlayers 13 in turn is a respective barrier layer 12, which consists of a polymeric binder and a wax based on a vegetable oil. The interlayers preferably comprise a pigment and a binder.

Example 1: Production of a Barrier Paper of the Invention

[0117] As paper substrate, a paper web provided with resin sizing in the stock and having a mass per unit area of 33.3 g/m.sup.2 was produced on a paper machine from short-fiber stocks (100% short-fiber pulp) having a freeness of 50 SR and with addition of talc as filler with a mass fraction of 1%, based on the total mass of the paper substrate. The paper substrate produced was calendered under a linear load of 100 kN/m and a temperature of 100 C.

[0118] A curtain coater was used to apply, to the front side, a priming coat comprising water, an aqueous dispersion of an acrylic-acetate copolymer (solids content 33%, mass fraction in the priming coat 0.03% (oven-dry); Sterocoll BL), an aqueous dispersion of an acrylic copolymer (solids content 40%, mass fraction in the priming coat 1.27% (oven-dry); trade name: Sterocoll FS), an aqueous dispersion of a styrene-acrylate copolymer (solids content 50%, mass fraction in the priming coat 70.5% (oven-dry); trade name: Sterocoll FS), and kaolin (solids content 70%, mass fraction in the priming coat 28.2% (oven-dry); trade name: Capim NP), with a coat weight of 3.5 g/m.sup.2, and the priming coat was subsequently dried by IR and air drying, to give an interlayer.

[0119] A curtain coater was used to apply, to the interlayer, a barrier coat comprising water, a wax based on a vegetable oil (solids content 30%, mass fraction in the priming coat 82% (oven-dry); trade name: SWX 155), a polyacrylate dispersion (solids content 48%, mass fraction in the priming coat 16.4% (oven-dry); trade name: Tecryl PB 16/3), and a mixture of nonionic surfactants (solids content 100%, mass fraction in the priming coat 1.6% (oven-dry); trade name: Metolat 700), with a coat weight of 4 g/m.sup.2, and the barrier coat was subsequently dried by means of IR and air drying, to give a barrier layer.

[0120] Samples were taken from the completed barrier paper, and typical parameters were determined from these samples and are collated in the table below.

TABLE-US-00001 KIT rating (Tappi 559) >12 Water vapor permeability 23 C./85% rh 115 g/(m.sup.2d) Water vapor permeability 38 C./90% rh 249 g/(m.sup.2d) Fat resistance palm kernel fat method I 8 breakthroughs (<1 mm) setting I > 24 h with weight 0 breakthroughs (>1 mm) Fat resistance palm kernel fat method II 0 breakthroughs (<1 mm) setting I > 24 h with weight 4 breakthroughs (>1 mm)

[0121] The results show that the barrier paper of the invention exhibits fat resistance outstandingly and a low water vapor permeability.

[0122] Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.