Primer composition

Abstract

A water-based primer composition comprising an porous submicron silica dispersion, preferably in an amount from 10 to 30 wt.-% based on the weight of the entire composition, starch, preferably in an amount from 10 to 30 wt.-% based on the weight of the entire composition, and at least one component selected from the group consisting of a further polysaccharide, a hemicellulose, lignin, a styrene-acrylic emulsion, a polyvinylacetate and a sulfopolyester. Further, use of the composition for preparing a primer layer on a substrate, to a method of printing on a substrate, comprising the steps of preparing a primer layer on at least a part of one surface of the substrate using the composition, and printing on the primer layer using a liquid toner, as well as to an article manufactured with the method is disclosed.

Claims

1. A water-based primer composition comprising: a porous submicron silica, starch, and at least one component selected from the group consisting of a further polysaccharide, a hemicellulose, lignin, styrene-acrylic emulsion, a polyvinylacetate and a sulfopolyester.

2. The primer composition according to claim 1, wherein the composition comprises water in an amount from 10 to 70 wt.-%, based on a weight of an entire composition.

3. The primer composition according to claim 1, wherein the starch is rice starch.

4. The primer composition according to claim 2, wherein the starch is rice starch.

5. The primer composition according to claim 1, wherein the at least one component is a further polysaccharide.

6. The primer composition according to claim 5, wherein the further polysaccharide is gum arabic.

7. The primer composition according to claim 1, wherein the at least one component is a hemicellulose or lignin or a styrene-acrylic emulsion.

8. The primer composition according to claim 7, wherein the hemicellulose is xylan.

9. The primer composition according to claim 1, wherein the at least one component is polyvinylacetate or sulfopolyester, or a combination thereof.

10. The primer composition according to claim 9, wherein the polyvinylacetate is a copolymer from vinyl acetate and a maleic ester.

11. The primer composition according to claim 9, wherein each of the polyvinylacetate and the sulfopolyester are present in an amount from 10 to 40 wt.-% based on a weight of an entire composition.

12. The primer composition according to claim 1, wherein the composition additionally comprises one or more additives selected from the group consisting of organic solvents, an anti-foaming agent and a biocide.

13. A method for manufacturing a composition according to claim 1, the method comprising mixing components of the composition together while stirring.

14. A method of use of the composition according to claim 1 for preparing a primer layer on a substrate, the method comprising applying the primer composition onto at least a part of one surface of the substrate.

15. A method of printing on a substrate, the method comprising: a) preparing a primer layer on at least a part of one surface of said substrate using the composition according to claim 1, and b) printing on said primer layer.

16. The method of printing on a substrate according to claim 15, further comprising using a liquid toner for printing on said primer layer.

17. An article manufactured according to the method of claim 14.

Description

EXAMPLE 1

(1) A first primer composition was prepared from the following components:

(2) TABLE-US-00001 TABLE 1 Component Amount (wt.-%) Porous submicron silica dispersion 20 Rice starch 20 Polyvinylacetate-dibutyl maleate copolymer 20 Sulfopolyester 20 Water 17.64 Isopropanol 2 Antifoaming agent 0.3 Biocide/preservative 0.06

(3) The sulfopolyester used in this example had a Tg of 55 C. (Tg was measured by DSC (Differential Scanning Calorimetry) according to DIN 51007)

(4) The composition was prepared by mixing the above components together under stirring at room temperature.

EXAMPLE 2

(5) A second primer composition was prepared from the following components:

(6) TABLE-US-00002 TABLE 2 Component Amount (wt.-%) Porous submicron silica dispersion 20 Rice starch 20 Xylane varnish (10% xylane in water) 35 Water 22.64 Isopropanol 2 Antifoaming agent 0.3 Biocide/preservative 0.06

(7) The composition was prepared by mixing the above components together under stirring at room temperature.

EXAMPLE 3

(8) A third primer composition was prepared from the following components:

(9) TABLE-US-00003 TABLE 3 Component Amount (wt.-%) Porous submicron silica dispersion 20 Rice starch 20 Gum arabic varnish (15% gum arabic in 40 water/ethanol (94:6)) Water 17.64 Isopropanol 2 Antifoaming agent 0.3 Biocide/preservative 0.06

(10) The composition was prepared by mixing the above components together under stirring at room temperature.

EXAMPLE 4

(11) A fourth primer composition was prepared from the following components:

(12) TABLE-US-00004 Component Amount (wt.-%) Porous submicron silica dispersion 20 Rice starch 20 Styrene-acrylic emulsion 40 Water 17.64 Isopropanol 2 Antifoaming agent 0.3 Biocide/preservative 0.06

(13) The styrene-acrylic emulsion used in this example had a Tg of 44 C. (Tg was measured by DSC (Differential Scanning Calorimetry) according to DIN 51007)

(14) The composition was prepared by mixing the above components together under stirring at room temperature.

(15) Printability Tests

(16) The primer compositions according to examples 1 to 4 were applied onto a coated DIN A4 paper (Invercote from Iggesund) by means of a RK manual tool with a soft rubber roll to achieve a thickness of 2.5 to 3 g/m.sup.2.

(17) Onto said substrate, a print was provided using an Officejet Pro 8100 ink-jet printing machine (this is a good model for printing systems using liquid toners).

(18) The printing quality was assessed on a scale from 0 (bad) to 5 (good).

(19) TABLE-US-00005 TABLE 4 Printability results Example Printability result Substrate with primer from example 1 4.2 Substrate with primer from example 2 4 Substrate with primer from example 3 4 Substrate with primer from example 4 4

(20) Transfer Test

(21) The primer compositions according to examples 1 to 4 were applied onto a coated DIN A4 paper (Invercote from Iggesund) by means of a RK manual tool with a soft rubber roll to achieve a thickness of 2.5 to 3 g/m.sup.2.

(22) Onto said substrate, a printed polyester substrate (polyester printed with ElectroInk from HP Indigo) was applied, so that the printed surface of the polyester substrate was adjacent to the primer layer on the paper substrate. The stack of the two substrates was passed through two rollers of a lamination machine (Polytype) with a speed of 10 m/min at a temperature of 80 C.

(23) It was evaluated on a scale from 0 (no transfer) to 5 (total transfer) how much ink was transferred under these conditions from the printed polyester substrate to the primer layer.

(24) TABLE-US-00006 TABLE 5 Transfer test results Example Transfer Substrate with primer from example 1 3.5 Substrate with primer from example 2 3 Substrate with primer from example 3 3 Substrate with primer from example 4 4