Paper material with virucidal, biocidal and barrier properties to water, fats and oils

Abstract

The paper material includes a base support having a mixture of cellulose fibres and other natural and / or synthetic fibres, at least one polymeric substance adapted to impart to the fibre mixture mechanical resistance, water resistance and a functional barrier to water, fats and oils, and an inorganic filler. The base support has at least one surface coat at least having an adhesive, transition metal complexes, isothiazolone-based compounds and inorganic pigments imparting barrier properties towards water, fats and oils, a metallic or matt appearance, and a virucidal and biocidal effect.

Description

DESCRIPTION

[0001] The present invention relates to a paper material capable of providing mechanical resistance, water resistance and a functional barrier to water, fats and oils, as well as a virucidal and biocidal effect.

[0002] In the paper sector, there is a constant search for new types of papers and cardboards for technical use having particular abilities and / or finishes.

[0003] As a function of the new pandemic situation, paper products obtained with cellulose fibres and / or cotton and / or synthetic fibres, and with additives based on synthetic polymers are on the market with the aim of reducing the virucidal load over time.

[0004] However, such products cannot simultaneously ensure the barrier properties to water and to fat and / or oils with pearlescent or matt surface effect and virucidal and biocidal properties.

[0005] There is therefore a need to produce a paper material which can overcome the limits of the prior art.

[0006] The technical task of the present invention is, therefore, to make a paper material of different grammage which allows to obviate the lamented technical drawbacks of the prior art.

[0007] Within the context of this technical task, an object of the invention is to make a paper material of different grammage with barrier properties towards water, fats and oils, a metallic or matt appearance, and a virucidal and biocidal effect.

[0008] Another object of the invention is to make a paper material of different grammage with the ability to be heat-sealable while maintaining the aforesaid barrier properties to water, fats and oils, a metallic or matt appearance, and a virucidal and biocidal effect.

[0009] Last but not least, an object of the invention is to make a paper material with the above properties and an acceptable printability.

[0010] The technical task, as well as this and other objects, are achieved according to the present invention by making a paper material characterised in that it comprises a base support comprising a mixture of cellulose fibres and other natural and / or synthetic fibres, at least one polymeric substance adapted to impart to the fibre mixture mechanical resistance, water resistance and a functional barrier to water, fats and oils, and an inorganic filler, characterised in that said base support has at least one surface coat at least comprising an adhesive, transition metal complexes, isothiazolone-based compounds and inorganic pigments adapted to impart barrier properties towards water, fats and oils, a metallic or matt appearance, and a virucidal and biocidal effect.

[0011] Preferably said inorganic pigments present in said coat include at least one pigment selected from calcium carbonate, kaolin, mica, titanium dioxide.

[0012] Preferably said adhesive includes at least one of a starch, a polyol, a silicone, an acrylic polymer, a synthetic or natural wax.

[0013] Preferably said fibre mixture comprises cellulose fibres, cotton fibres and synthetic fibres.

[0014] Preferably said polymeric substance comprises one or more colophony-based and / or alkyl-ketene-dimer-based and / or acetyl succinic-acid-based and / or epichlorohydrin-based and / or carboxymethylcellulose-based resins.

[0015] Preferably said inorganic filler is a mineral filler comprising one or more substances selected from the group consisting of carbonates, kaolins, talc and mixtures thereof.

[0016] In a preferred embodiment of the invention, the content of transition metal complexes is comprised between 1% by weight and 5% by weight, the content consisting of isothiazolone-based compounds is comprised between 1% by weight and 5% by weight, the content of said at least one adhesive is comprised between 1% by weight and 10% by weight, the content of said inorganic pigments is comprised between 1% by weight and 5% by weight.

[0017] In a preferred embodiment of the invention the cellulose fibre content is comprised between 50% and 90% by weight.

[0018] Other features of the present invention are further defined in the following claims.

[0019] Further features and advantages of the invention will more fully emerge from the description of a preferred but not exclusive embodiment of the paper material according to the invention, illustrated hereinafter by way of non-limiting example.

[0020] The present invention relates to a paper material (paper / cardboard) which, by virtue of a specially studied pulp, a specific surface treatment and a production method, has a structure with extreme mechanical resistance, with the ability to be folded without tearing to ensure adequate protection from water, fats, oils and gases as well as a virucidal and biocidal effect.

[0021] The paper material of the invention is also printable with an acceptable printing quality and allows to obtain particular graphic effects, which are difficult to obtain with traditional treated-paper materials.

[0022] In detail, the paper material of the invention comprises a base support comprising a mixture of cellulose fibres with natural and / or synthetic fibres, at least one polymeric substance, adapted to confer to the fibre mixture mechanical resistance (dry and wet) and water resistance, and an inorganic filler, adapted to confer to the material good features of machinability and chemical stability.

[0023] According to a particularly advantageous aspect of the invention, such a base support has at least one surface coat at least comprising an adhesive, transition metal complexes, isothiazolone-based compounds and inorganic pigments adapted to impart barrier properties towards water, fats and oils, a metallic or matt appearance and a virucidal, biocidal effect.

[0024] More precisely, the content of transition metal complexes in the paper material is comprised between 1% by weight and 5% by weight, the content of isothiazolone-based compounds is comprised between 1% by weight and 5% by weight, the content of said at least one adhesive is comprised between 1% by weight and 10% by weight, the content of said inorganic pigments is comprised between 1% by weight and 5% by weight.

[0025] The cellulose fibre content in the paper material is comprised between 50% and 90% by weight.

[0026] The fibre mixture preferably comprises cellulose fibres, cotton fibres and synthetic fibres in a variable percentage proportion by weight: the length of the cellulose fibres is comprised between 0.2 mm and 5.0 mm; the content of the cotton fibres and the synthetic fibres in the fibre mixture is in proportions varying between 1% and 50% by weight.

[0027] Preferably, the polymeric substance included in the base support comprises one or more colophony-based and / or alkyl-ketene-dimer-based and / or acetyl succinic-acid-based and / or epichlorohydrin-based and / or carboxymethylcellulose-based resins.

[0028] Preferably the inorganic filler is a mineral filler comprising one or more substances selected from the group consisting of carbonates, kaolins, talc and mixtures thereof.

[0029] In the formulation of the coat advantageously the adhesive includes at least one of a starch, a polyol, a silicone, an acrylic polymer, a synthetic or natural wax.

[0030] Furthermore, in the formulation of the coat advantageously the inorganic pigments comprise at least one pigment selected from calcium carbonate, kaolin, mica, titanium dioxide.

[0031] In more detail, the following formulation was found to be convenient for the paper material (percentages expressed in weight of the paper material).Base Support:cellulose fibres between 50% and 90% by weight

[0033] natural and / or synthetic fibres between 1% and 10% by weight

[0034] polymeric substance between 1% and 10% by weight

[0035] inorganic filler between 2% and 40% by weightSurface Coat:adhesive: between 1% and 10% by weight

[0037] transition metal complexes between 1% and 5% by weight

[0038] isothiazolone-based compounds between 1% and 5% by weight

[0039] inorganic pigments between 1% and 5% by weight

[0040] More in particular, the following specific formulation was found to be convenient for the paper material (percentages expressed in weight of the paper material).Base Support:cellulose fibres 55% by weight

[0042] natural and / or synthetic fibres: cotton fibres 1% by weight and synthetic fibres 1% by weight

[0043] polymeric substance: epichlorohydrin-based resin 2% by weight and carboxymethylcellulose-based resin 1% by weight

[0044] inorganic filler: calcium carbonate 26% by weightSurface Coat:adhesive: styrene acrylic latex 8% by weight

[0046] transition metal complexes 2% by weight

[0047] isothiazolone-based compounds 3% by weight

[0048] inorganic pigments: titanium dioxide 1% by weight

[0049] The grammage of the paper material according to the present invention is comprised between about 50 gr / m2 and about 900 g / m2.

[0050] The paper material described above is made in accordance with a further aspect of the present invention, with the method comprising the steps of:

[0051] (a) preparing an aqueous pulp containing the cellulose fibres and other natural and / or synthetic fibres, the polymeric substance and the inorganic filler;

[0052] (b) removing water from the pulp so as to form the base support of the paper material;

[0053] (c) applying the coat to the base support by treating at least one surface of the base support with at least one aqueous solution comprising the adhesive, the transition metal complexes, the isothiazolone-based compounds, and the inorganic pigments.

[0054] In more detail, the paper material is made with a substantially known paper forming technique, for example on a continuous paper manufacturing machine.

[0055] The aqueous pulp is arranged and thereafter, water is removed from the pulp so as to form the base support of the paper material.

[0056] The following step is the surface treatment of one or both sides of the base support with an aqueous solution comprising the adhesive, the transition metal complexes, the isothiazolone-based compounds, and the inorganic pigments.

[0057] The method can subsequently comprise, after the surface treatment of the base support with the aqueous solution, a smoothing step of the paper material which is smoothed to Bendtsen ISO 2494 smoothness values less than about 400 ml / min.

[0058] The method also comprises a step of mechanically treating the paper material to obtain a porosity from 20 sec to 200 sec according to the Gurley method.

[0059] Finally, the method can comprise a further mechanical treatment step of the surface, in particular an embossing step.

[0060] Advantageously, a paper material made in accordance with the present invention can be used as a support layer of multi-layered products which can be used in the food and pharmaceutical industry.

[0061] Modifications and variations may be made to the paper material and the relative manufacturing method according to the present invention and described and illustrated herein which do not fall outside the scope of the inventive concept as defined in the attached claims.

Claims

1-9. (canceled)10. A paper material, comprising a base support comprising cellulose fibres in a mixture with natural fibres or with synthetic fibres or with both natural and synthetic fibres, at least one polymeric substance comprising one or more colophony-based and / or alkyl-ketene-dimer-based and / or acetyl-succinic-acid-based and / or epichlorohydrin-based and / or carboxymethylcellulose-based resins, and an inorganic filler, wherein said base support has at least one surface coat at least comprising an adhesive, transition metal complexes, isothiazolone-based compounds and inorganic pigments, said inorganic pigments including at least one pigment selected from calcium carbonate, kaolin, mica, titanium dioxide, said adhesive including at least one of a starch, a polyol, a silicone, an acrylic polymer, a synthetic or natural wax.

11. The paper material according to claim 10, wherein said base support comprises said cellulose fibres in a mixture with cotton fibres and synthetic fibres.

12. The paper material according to claim 10, wherein said inorganic filler is a mineral filler comprising one or more substances selected from the group consisting of carbonates, kaolins, talc and mixtures thereof.

13. The paper material according to claim 10, wherein a content of the transition metal complexes is comprised between 1% by weight and 5% by weight, a isothiazolone content is comprised between 1% by weight and 5% by weight, a content of said at least one adhesive is comprised between 1% by weight and 10% by weight, a content of said inorganic pigments is comprised between 1% by weight and 5% by weight.

14. The paper material according to claim 10, comprising the following percentage composition by weight:cellulose fibres between 50% and 90% by weightnatural and / or synthetic fibres between 1% and 10% by weightpolymeric substance between 1% and 10% by weightinorganic filler between 2% and 40% by weightadhesive: between 1% and 10% by weighttransition metal complexes between 1% and 5% by weightisothiazolone-based compounds between 1% and 5% by weightinorganic pigments between 1% and 5% by weight15. The paper material according to claim 10, wherein a grammage of the paper material is comprised between 50 gr / m2 and 900 g / m2.

16. A method for manufacturing a paper material according to claim 10, the method including the following steps:(a) preparing an aqueous pulp containing said cellulose fibres and other natural and / or synthetic fibres, said at least one polymeric substance and said inorganic filler,(b) removing water from the aqueous pulp so as to form said base support of the paper material, and(c) applying said coat to said base support by treating at least one surface of said base support with at least one solution comprising said adhesive, said transition metal complexes, said isothiazolone-based compounds, said inorganic pigments.

17. The method for manufacturing a paper material according to claim 16, wherein after the application of said coat, a smoothing step of the base support is carried out, in which the base support is smoothed to Bendtsen ISO 2494 smoothness values less than about 400 ml / min.

18. The method for manufacturing a paper material according to claim 17, wherein a mechanical treatment of the base support is carried out to obtain a porosity from 20 sec to 200 sec according to Gurley method.