COMPOSITION AND METHOD FOR PRODUCING PRE-IMPREGNATED DECORATIVE BASE PAPER COMPRISING BIOPOLYMER NANOPARTICLES

Abstract

A pre-impregnated decorative base paper for decorative coating materials, comprising biopolymer nanoparticles.

Claims

1: A preimpregnated decorative base paper for decorative coating materials, comprising biopolymer nanopartieles.

2: The pre-impregnated decorative base paper of claim 1, wherein the pre-impregnated decorative base paper is obtained by impregnating a decorative base paper with an impregnating composition, comprising a petroleum based polymer latex binder and biopolymer nanoparticles.

3: The pre-impregnated base paper of claim 2, wherein the petroleum based latex binder is selected from the group of styrene butyl acrylate copolymers, styrene butyl actylate acrylonitrile copolymers, styrene acrylics derivate copolymers, and mixtures thereof

4: The pre-impregnated decorative base paper of claim 1 wherein the biopolymer nanoparticles are made up of at least 50% starch.

5: The pre-impregnated decorative base paper according to claim 2, wherein the weight ratio dry of biopolymer nanoparticles to petroleum based polymer(s) is in the range of 20:80 to 80:20.

6: The pre-impregnated decorative base paper of claim 1, wherein the average size D.sub.50 in number of the biopolymer nanoparticles is less than or equal to 1000 nm as measured by Nanoparticle Tracking Analysis.

7: The pre-impregnated decorative base paper of claim 4, wherein the starch is processed, at a temperature of between 40° C. and 200° C., a crosslinking agent being present during the processing, and the starch being submitted during the processing to shear forces.

8: The pre-impregnated decorative base paper of claim 1, wherein the molecular weight polydispersity index Mw/Mn of the biopolymer nanoparticles is less than or equal to 2 as measured by Gel Permeation Chromatography.

9: The pre-impregnated decorative base paper of claim 1, where the biopolymer nanoparticles comprise one or more types of starch.

10: A method for producing the pre-impregnated decorative base paper of claim 1, comprising impregnating a decorative base paper with an impregnating composition comprising a petroleum based latex and a dispersion of biopolymer nanoparticles.

11: The method of claim 10, the decorative base paper having before impregnation a Bendsten porosity ranging from 100 to 1500 mL/min.

12: The method of claim 10, wherein the impregnating composition comprises a petroleum based polymer latex binder and biopolymer nanoparticles, the petroleum based polymer is selected from the group consisting of styrene copolymers, styrene acrylate copolymers, styrene butyl acrylate copolymers, styrene butyl acrylate acrylonitrile copolymers, and styrene acrylics derivate, and mixtures thereof.

13: The method of claim 10, the viscosity of the impregnating composition at 23° C. being 150 mPa.Math.s or less.

14: The method of claim 10, wherein the dry solids contents of the impregnating composition ranges from 20 to 40%.

15: The method of claim 10, wherein the decorative base paper is treated with a quantity of the impregnating composition such that the dry weight of the impregnating composition ranges from 10 to 25% of the weight of the decorative base paper.

16: The method of claim 12, wherein the dry weight ratio of biopolymer nanoparticles to the petroleum based polymer(s) is in the range of 20:80 to 80:20.

17: The method of claim 12, wherein the dry weight ratio of biopolymer nanoparticles to the petroleum based polymer(s) is in the range of 40:60 to 70:30.

18: The method of claim 12, the impregnating solution being obtained by mixing an aqueous dispersion of the biopolymer nanoparticles with the petroleum based polymer latex binder, the solid content of the biopolymer nanoparticles dispersion is 25 to 35% of the total weight of said aqueous dispersion, said aqueous dispersion being prepared by adding, 4% to 6% of urea by weight of the biopolymer nanopartieles.

19. The method of claim 13, the viscosity of the impregnating, composition at 23° C. being from 40 to about 100 mPa.Math.s.

20. The method of claim 15, wherein the decorative base paper is treated with a quantity of the impregnating composition such that the dry weight of the impregnating composition ranges from 15 to 20% of the weight of the decorative base paper,

21: The method of claim 14, wherein, the dry solids contents of The impregnating composition ranges from 25 to 35%.

22: The method of claim 12, wherein the impregnating composition is an aqueous composition,

23. The method of claim 12, wherein the impregnating solution is obtained by mixing an aqueous dispersion of the biopolymer nanoparticles with the petroleum based polymer latex binder, the solid content of the biopolymer nanoparticles dispersion is 15 to 35% of the total weight of said aqueous dispersion.

24: The pre-impregnated decorative base paper according to claim 2, wherein the weight ratio dry of biopolymer nanoparticles to petroleum based polymer(s) is in the range of 10:60 to 70:30.

25: The pre-impregnated decorative base paper of claim 1, wherein the average size D.sub.50 in number of the biopolymer nanoparticles is less than or equal to 400 nm as measured by Nanoparticle Tracking Analysis.

26: The pre-impregnated decorative base paper of claim 4, wherein the starch is extruded at a temperature of between 40° C. and 200° C., a crosslinking agent being present during the extruding, and the starch is dissolved or dispersed in a hydroxylic solvent during the extruding, the starch being submitted during the extruding to shear forces.

27: The pre-impregnated decorative base paper of claim 1, wherein the molecular weight polydispersity index Mw/M of the biopolymer nanoparticles is less than or equal to 2 as measured by Gel Permeation Chromatography, with an average molecular weight of at least 1,000,000 Da.

28: The pre-impregnated decorative base paper of claim 1, wherein the biopolymer nanoparticles comprise one or more types of starch selected from the group consisting of a native corn starch, a tubular starch, a chemically modified starch, and mixtures thereof.

29: The method of claim 10. the decorative base paper baying before impregnation a Bendsten porosity ranging from 300 to 1000 mL/min.

Description

EXAMPLES

[0049] The following examples serve to illustrate the invention and are not intended to limit the invention in any way. Indeed, various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description and the following examples and fall within the scope of the appended claims. Tests have been carried out to assess properties of pre-impregnated decorative base papers made in accordance with the invention, compared to comparative examples.

[0050] The lacquer used is the 5364.1 mixed with the hardener 9021.2 both of which were obtained from the company Plantag.

Control Example A

[0051] This pre-impregnated paper is made in accordance with the teaching of EP 0,648,248 B1 using an all-synthetic petroleum based binder system, including a main latex binder and a water soluble polyvinyl alcohol (PVOH) cobinder.

Control Example B

[0052] This pre-impregnated paper is made in accordance with the teaching of U.S. Pat. No. 8,349,464 with the starch referenced 07311 of the company CARGILL. The starch is prepared at 25% weight solid contents.

[0053] The dry weight ratio of starch/polymer latex in this example is 60:40.

Control Example C

[0054] This pre-impregnated paper is made in accordance with the teaching of U.S. Pat. No. 8,349,464 with the starch referenced 07325 supplied by the company CARGILL. The starch is prepared at 25% weight solid contents.

[0055] The dry weight ratio of starch/polymer latex in this example is 60:40.

Example 1 to 4

[0056] Examples 1 to 4 are made in accordance with the invention, with respective ratios of 80:20, 60:40, 40:60 and 20:80 of biopolymer nanoparticles (supplied by the company EcoSynthetix Corporation) with respect to polymer latex. The aqueous latex dispersion of biopolymer nanoparticles is prepared at 35.7% weight solid contents.

[0057] For all the examples, the details of the impregnating compositions are given in the table below.

[0058] The proportions are weight proportions, unless specified otherwise.

[0059] The base paper is made from a fibrous composition of 100% eucalyptus pulp or comprising at the most 20% of long fibers of 58 gsm. The refining is about 30° SR and is adjusted so as to have a Bendsten porosity before impregnation of 100 to 1000 mL/min. Titanium dioxide is added up to 23% ash content, and a wet resistance agent such as epichlorohydrine is added between 0.3% and 1% dry versus the base paper.

[0060] This base paper is treated on line, with the impregnating composition applied using a size press and then dried at 120 ° C. to a moisture level of 2.5%.

TABLE-US-00001 Control Control Control Example Example Example A B C Example 1 Example 2 Example 3 Example 4 Biobased Binder 0% 60% 60% 80% 60% 40% 20% % Water 10.4 115.0 80.0 80.0 85.0 101.0 115.0 Cargill 07311 240.0 Cargill 07325 240.0 Biopolymer 224.1 168.1 112.0 56.0 nanoparticles (1) Polymer latex (2) 160 80.0 80.0 40.0 80.0 120.0 160.0 PVOH (3) 200 Solid content 27.0 23.0 25.0 29.1 30.0 30.0 30.2 Viscosity 100 trs 60 200 65 75 70 50 40 (cps) Pick up 19.7 16.6 19.3 18.7 20.0 21.7 20.3 %/treated paper Bendtsen 15 64 124 138 121 76 40 porosity (ml/min) Internal bond SM 2400 1150 1200 1200 2200 2300 2400 (J/m.sup.2) Water cobb 1 min 13.8/ 20.7/ 18.9/ 31.0/ 23.7/ 25.2 17.6/18 13.5/14.3 Top side/Back 14.7 21.2 19.7 33.7 side (gsm) Tesa test 1 5 3 3 1 1 1 Gloss 60° 29.4 28.3 27.1 28.4 27 29.1 29.8 8 gsm of lacquer (%) Gluability Poor very very good very good very good good medium good (1) Starch nanoparticles, grade DuraBind ™ 3356, were obtained from EcoSynthetix Corporation. (2) Aqueous dispersion with 50% weight solid contents of a heat-crosslinking copolymer of n-butyl acrylate and styrene sold under reference Acronal S305D by the company BASF. (3) Polyvinyl alcohol from the company KURARAY sold under reference Mowiol 4/98, with 10% weight solid contents.

[0061] Example 2 shows over Control Example B and C that with similar contents of polymer latex the internal bond is significantly improved.

[0062] Example 1 shows over Control Example B and C that with comparable internal bond the amount of polymer latex can be significantly reduced.

[0063] Examples made in accordance with the invention show improved gluability with respect to Control Example A.

[0064] The examples made according to the invention also show acceptable viscosity for processing.

[0065] The tests show that the pre-impregnated decorative base paper in accordance with the invention exhibit good results for gluability, gloss and internal bond. What is quite surprising is to get an excellent compromise between the two opposing key properties of gluability and lacquer hold out, by using the biopolymer nanoparticles. Furthermore, equally surprising is the high level of petroleum based latex binder replacement with the biopolymer nanoparticles, combined with the total elimination of the PVOH cobinder. This is totally unexpected especially given that PVOH is known to have more than twice the binding strength of the petroleum based latex binder. Furthermore, these results demonstrate that this performance is not achieved using water-soluble starches.

[0066] The invention is not limited to the disclosed embodiments. For example, biopolymer nanoparticles other than those made in accordance with U.S. Pat. No. 6,677,386 could be used.