Agricultural Fibre-Based Paper

Abstract

The present invention resides in a lamination or specialty paper, such as dcor paper, suitable for lamination, wherein the paper has a furnish in which the fibre portion comprises between 1% and 100% non-wood pulp. Also disclosed is a method for making a non-wood based paper comprising forming an unrefined slurry of bleached or unbleached non-wood pulp, blending the slurry with chemical or mineral additives, and passing the slurry into a paper-making machine.

Claims

1. A decor or lamination paper for lamination, wherein the paper has a furnish in which the fibre portion comprises between 1% and 100% non-wood pulp.

2. The decor or lamination paper as claimed in claim 1, wherein the fibre portion of the furnish comprises 50% to 100% non-wood pulp.

3. The decor or lamination paper as claimed in claim 1, wherein the fibre portion of the furnish comprises 75% to 100% non-wood pulp.

4. The decor or lamination paper as claimed in claim 1, wherein the non-wood pulp is derived from one or more families of plant materials.

5. The decor or lamination paper as claimed in claim 4, wherein the plant material is derived from crop residue from the production of cereals, legumes, sugar, bamboo, reeds and perennial grasses, bast plants and/or leaf fibres.

6. The decor or lamination paper as claimed in claim 4, wherein the plant material is selected from flax, hemp, oats, rye, wheat, barley, jute, kenaf, rice, cotton, corn, maize, alfalfa, millet, sugar cane, sorghum, triticale, bamboo, Job's Tears, Eragrostis, Digitaria, Phalaris, Agave sisalana, Musa textilis, perennial grasses, perennial plants, pseudocereals and combinations thereof.

7. The decor or lamination paper as claimed in claim 1, wherein the non-wood pulp is derived from fibrous crop residue from production of cereals, legumes, sugar, and combinations thereof.

8. The decor or lamination paper as claimed in claim 7, wherein the cereals are selected from: wheat, oats, barley, rice, triticale, rye, and combinations thereof.

9. The decor or lamination paper as claimed in claim 1, wherein the furnish further comprises a bonding agent that is a synthetic, plant-based or bio-based resin.

10. The decor or lamination paper as claimed in claim 9, wherein the resin is a thermosetting resin selected from the group consisting of: melamine, polyurethanes, acrylics, epoxy resins, phenolic resins, polyester resins and mixtures thereof.

11. A method for making a non-wood based paper, wherein the method comprises forming a slurry of unrefined bleached or unbleached non-wood pulp, blending the slurry with chemical or mineral additives, and passing the slurry into a paper-making machine.

12. The method according to claim 11, wherein the method further comprises blending the slurry of unrefined non-wood pulp with a slurry of refined wood pulp.

13. The method according to claim 11, wherein the method further comprises blending the slurry of unrefined non-wood pulp with a slurry of refined non-wood pulp.

14. The method according to claim 13, wherein the slurry of refined non-wood pulp is refined using less than 50 kWh/ODMT.

15. The method according to claim 13, wherein the slurry of refined non-wood comprises sugarcane bagasse.

16. The method according to claim 12, wherein the slurry of refined wood pulp comprises softwood pulp.

17. The method according to claim 11, wherein the method further comprises adding a mineral filler, such as ash.

18. (canceled)

Description

EXAMPLE 1

[0054] In 2004, a study sponsored by Alberta Agriculture Research Institute (AARI) explored the behaviour of wood and non-wood chemical pulp properties during the refining process. Table 1 shows the results from unrefined pulps of spruce, aspen, Eucalyptus and wheat. The wheat pulp for this study was a commercial pulp sourced from China.

TABLE-US-00001 TABLE 1 Euca- Analysis Unit Spruce Aspen lyptus Wheat PFI, TAPPI.sup. revs 0 0 0 0 C.S. Freeness mLs 631 487 500 483 Bulk cc/g 1.72 1.71 1.98 1.59 Tear index mN .Math. m.sup.2/g 25.8 2.7 2.8 3.5 Burst index kPa .Math. m.sup.2/g 2.96 0.72 0.68 2.41 Tensile index N .Math. m/g 37.3 20.7 20.7 51.4 Stretch % 3.20 0.94 1.15 2.12 Tensile Energy J/m.sup.2 51.9 7.5 9.3 44.5 Absorption Roughness OR SCCM 228 181 243 143 Smoothness* Air permeability OR SCCM 1675 1781 2376 115 porosity* .sup.TAPPITechnical Association of the Pulp and Paper Industry *Bendtsen surface roughness and air permeability tests were used.

[0055] Table 2 shows data from the same study comparing refined pulps of spruce, aspen, Eucalyptus and wheat. Again, Bendtsen surface roughness and air permeability tests were used.

TABLE-US-00002 TABLE 2 Euca- Analysis Unit Spruce Aspen lyptus Wheat PFI, TAPPI revs 9,138 9,019 10,000 1,000 C.S. mLs 265 265 265 269 Freeness Bulk cc/g 1.32 1.48 1.67 1.49 Tear index mN .Math. m.sup.2/g 10.3 7.1 8.1 3.3 Burst index kPa .Math. m.sup.2/g 8.63 2.52 2.88 3.50 Tensile N .Math. m/g 105.1 47.0 50.9 65.6 index Stretch % 4.29 3.15 3.27 2.99 Tensile J/m.sup.2 179.7 66.3 70.4 79.5 Energy Absorption Roughness* SCCM 64 77 107 56 Air perme- SCCM 34 202 685 29 ability* *Bendtsen surface roughness and air permeability tests were used.

[0056] The data shows that the wheat furnish required much less refining energy than wood-based furnishes to achieve the same freeness. In addition, the wheat furnish had a lower tear strength than wood furnishes, but the tensile, burst, and tensile energy absorption (TEA) properties of the wheat furnish were superior to refined hardwoods (Eucalyptus, Aspen).

EXAMPLE 2

[0057] The aim of this experiment was to compare the properties of unrefined wheat against unrefined and refined sugarcane bagasse as a function of refining extent. Sugarcane bagasse pulp was refined in a laboratory PFI mill in accordance with standard TAPPI test methods.

[0058] It is to be understood that the wheat straw pulp sourced for this study was inferior to that used in the AARI study. In this example, the sugarcane bagasse pulp was either unrefined or refined at 100 or 5500 PFI revolutions. The wheat straw was unrefined.

[0059] The resulting papers were analysed and the results are set out in Table 3.

TABLE-US-00003 TABLE 3 Analysis Unit Wheat Straw Sugarcane Bagasse PFI, TAPPI revs 0 0 100 5500 C.S. Freeness mLs 264 501 481 264 Basis weight, g/m.sup.2 65.70 65.63 66.92 65.86 conditioned Bulk cc/g 1.31 1.64 1.47 1.33 Caliper ml 3.40 4.23 3.86 3.44 Burst index kPa .Math. m.sup.2/g 2.27 2.10 2.58 3.62 Tear index mN .Math. m.sup.2/g 2.56 6.15 6.14 5.97 Tensile index N .Math. m/g 44.4 38.5 44.8 58.9 Tensile km 4.53 3.92 4.57 6.01 Stretch % 1.84 2.17 2.39 3.16 Tensile Energy J/m.sup.2 37.9 38.9 51.4 89.3 Absorption Smoothness* SCCM 620 1984 1669 952 Porosity* SCCM 223 2997 1750 245 Brightness, ISO.sup. % 71.2 42.4 41.6 39.6 Opacity, ISO % 85.8 93.2 92.0 88.8 *Sheffield smoothness and porosity (0.75 orifice) tests were used. .sup.ISO refers to the standard method used to test brightness which is that published by the International Standards Organisation.

EXAMPLE 3

[0060] Analysis of the non-wood fibre pulps in Example 2 was used to inform the creation of two blends of non-wood fibres.

[0061] In particular, the experiment allowed the comparison of paper made from pure unrefined wheat with pure sugarcane refined at 100 PFI revolutions and blends of unrefined wheat and sugarcane refined at 100 PFI revolutions.

[0062] Analysis of the resulting papers is set out in Table 4.

TABLE-US-00004 TABLE 4 60% 70% Sugarcane Sugarcane Sugar Bagasse + Bagasse + Wheat Cane 40% 30% Refined Analysis Unit Straw Bagasse Wheat straw Wheat straw wood % sugarcane 0.1% 100.0% 60.0% 70.0% 0% C.S. Freeness mLs 264 481 384 418 N/A Basis weight, conditioned g/m.sup.2 65.70 66.92 65.81 67.39 62.63 Bulk cc/g 1.31 1.47 1.39 1.44 1.18 Caliper ml 3.40 3.86 3.61 3.82 2.91 Burst index kPa .Math. m.sup.2/g 2.27 2.58 2.34 2.30 1.17 Tear index mN .Math. m.sup.2/g 2.56 6.14 4.86 5.09 4.025 Tensile index N .Math. m/g 44.4 44.8 45.6 43.7 30.45 Tensile km 4.53 4.57 4.65 4.46 N/A Stretch % 1.84 2.39 2.21 2.19 4.44 Tensile Energy Absorption J/m.sup.2 37.9 51.4 47.7 46.6 30.45 Smoothness.sup. SCCM 620 1669 1142 1339 627 Porosity.sup. SCCM 223 1750 644 972 1316 Optical Properties: Brightness, ISO % 71.2 41.6 50.4 48.4 86.8 Opacity, ISO % 85.8 92.0 91.5 91.7 96.05 * Sugarcane Bagasse pulp was refined at 100 PFI revolutions. Wheat straw pulp was unrefined .sup.Sheffield smoothness and porosity (0.75 orifice) tests were used.

[0063] Sugarcane bagasse clearly increases bulk, tear strength, tensile energy absorption, roughness and porosity.

[0064] Based on strength and porosity, a blend of 70% sugarcane bagasse and 30% wheat straw was used for further experiments.

EXAMPLE 4

[0065] This experiment illustrates the impact of adding Northern bleached softwood kraft (NBSK) pulp (60-70% Pine, 25-33% Spruce and 5% Fir) to a blend of 70% refined sugarcane bagasse pulp and 30% unrefined wheat straw pulp on the resulting calliper (thickness), smoothness and porosity of the blended sheet. Due to its high fibre length and low fibre coarseness, NBSK is one of the most commonly used pulps in the paper industry for increasing paper strength.

[0066] The NBSK pulp was refined at 1000 PFI revolutions before addition to the wheat straw/sugarcane bagasse blend. As with Example 3, the wheat straw pulp was unrefined and the sugarcane bagasse pulp was refined at 100 PFI revolutions.

[0067] Analysis of the resulting sheets is set out in Table 5.

TABLE-US-00005 TABLE 5 70% sugarcane bagasse/30% wheat straw 0% 5% 10% 20% refined refined refined refined Analysis Unit NBSK NBSK NBSK NBSK C.S. Freeness mLs 418 435 457 528 Caliper ml 3.82 3.66 3.67 3.62 Smoothness.sup. SCCM 1339 1177 1250 1444 Porosity.sup. SCCM 972 780 952 1252 * Sugarcane Bagasse pulp was refined at 100 PFI revolutions. Wheat straw pulp was unrefined. .sup.Sheffield smoothness and porosity (0.75 orifice) tests were used.

[0068] The data show a role for refined softwood in papermaking (superior tear, tensile, burst, Tensile Energy Absorption) compared to hardwoods and non-woods.

[0069] It will be appreciated that other non-wood pulps may be sourced to offset softwood use as reinforcement, particularly of tear strength. Pulps from bamboo, cotton and bast fibre crops such as flax and hemp are specifically known for their tear strength.

EXAMPLE 5

[0070] In this experiment, precipitated calcium carbonate (PCC) was added to the blend of Example 4 containing 10% refined NBSK. PCC (Socal NR2, Solvay Chemicals) was added as a mineral filler to increase brightness and opacity.

[0071] Table 6 sets out the analysis of the resulting paper sheets.

TABLE-US-00006 TABLE 6 0% 25% 50% 50% PCC PCC* PCC* PCC.sup. 10% refined NBSK Analysis Unit 70% Sugarcane Bagasse/30% Wheat straw Caliper mils 3.67 3.79 4.10 3.71 Bulk cc/g 1.52 1.53 Burst index kPa .Math. m.sup.2/g 1.20 0.92 Tear index mN .Math. m.sup.2/g 5.29 4.21 Tensile index N .Math. m/g 25.1 20.7 Stretch % 2.11 1.57 Tensile Energy J/m.sup.2 24.5 14.4 Absorption Smoothness.sup. SCCM 1250 1475 1527 1442 Porosity.sup. SCCM 952 2069 2336 2382 Optical Properties: Brightness, ISO % 61.2 65.3 Opacity, ISO % 96.0 95.8 Analytical: Ash @ 525 C. % 0 12.8 20.5 28.0 *10% refined NBSK at 1000 revolutions + 90% [70% Sugarcane Bagasse (refined at 100 PFI revolutions)/30% Wheat straw soda AQ pulp (unrefined)] .sup.10% refined NBSK at 9300 revolutions + 90% [70% Sugarcane Bagasse (refined at 100 PFI revolutions)/30% Wheat straw soda AQ pulp (unrefined)] .sup.Sheffield smoothness and porosity (0.75 orifice) tests were used.

[0072] As can be seen, porosity increased dramatically and suggests that tensile strength may be increased by additional refining of the sugarcane bagasse portion of the furnish.

[0073] It will be appreciated that parameters and blends may be changed to produce a paper having specific properties. For example, burst, tensile, stretch and Tensile Energy Absorption properties could all be improved with additional refining of sugarcane bagasse, by adding 20% heavily-refined NBSK and sourcing a better wheat pulp.

[0074] Further optimisation of wet end sizing and retention chemistry, as well as soft calendaring of the sheet, will improve these properties. This type of optimisation is best performed on a paper machine, where the impact of paper machine white water recirculation may be taken into account.