Aqueous coating composition

Abstract

This invention relates to an aqueous coating composition, a greaseproof article and a process of forming a coating on a substrate. The aqueous coating composition comprises at least the following components: an organopolysiloxane (A) which is a polysiloxane compound having at least two alkenyl groups per molecule, an organohydrogenpolysiloxane (B) which is a polysiloxane compound comprising at least two Si H groups per molecule, an hydrosilylation catalyst (C) able to catalyse an hydrosilylation reaction between the organopolysiloxane compound (A) and the organohydrogenpolysiloxane compound (B), an organic copolymer (D) comprising at least two types of repeating units (i) and (ii): unit (i) which is an alkyl group comprising from 2 to 2 carbon atoms, unit (ii) which is an alkyl group comprising from 2 to 12 carbon atoms and having at least one pendant alcohol substituent, water, and the composition is able to form upon curing by hydrosilylation a coating on a substrate.

Claims

1. An aqueous coating composition comprising at least the following components: a. An organopolysiloxane (A) which is a polysiloxane compound having at least two alkenyl groups per molecule, b. An organohydrogenpolysiloxane (B) which is a polysiloxane compound comprising at least two SiH groups per molecule, c. An hydrosilylation catalyst (C) able to catalyse an hydrosilylation reaction between the organopolysiloxane compound (A) and the organohydrogenpolysiloxane compound (B), d. An organic copolymer (D) comprising at least two types of repeating units: i. unit (i) which is an alkyl group comprising from 2 to 12 carbon atoms ii. unit (ii) which is an alkyl group comprising from 2 to 12 carbon atoms and having at least one pendant alcohol substituent, wherein the copolymer (D) is ethylene-vinyl alcohol copolymer or ethylene-vinyl alcohol-vinyl ester copolymer, and e. Water, and the composition is able to form upon curing by hydrosilylation a coating on a substrate.

2. The composition according to claim 1 wherein components (A) and (B) are comprised in one or more oil-in-water emulsions.

3. The composition according to claim 1 wherein the copolymer (D) is water-soluble or water-dispersible.

4. The composition according to claim 1 wherein the copolymer (D) comprises 0.1 to 20 mol % of ethylene units and the total content of vinyl alcohol units and vinyl ester units is from 80 to 99.9 mol %.

5. The composition according to claim 1 further containing at least one of: hydrocolloid, polysaccharide, cellulose derivative, starch, alginate, carrageenan, gellan gum, locust bean gum, pectin, xanthan, guar gum, arabic gum, latexes.

6. The composition according to claim 1 further containing maleic anhydride or succinic anhydride derivative preferably alkyl or alkenyl C3 to C20 derivative such as 2-methyl-2-propenyl, octyl, octenyl, dodecyl, dodecenyl succinic anhydride.

7. The composition according to claim 1 wherein the weight ratio of component (D) to the siloxane components (A) and (B) is comprised between 0.01 and 10.

8. The composition according to claim 1 wherein the components are present in separate parts or packages.

9. The composition according to claim 1 wherein the alkenyl groups of component (A) are vinyl groups.

10. The composition according to claim 9 wherein the H/Vinyl ratio range of components (A) and (B) is comprised between 1 and 3.

11. A greaseproof article comprising a substrate bearing a coating formed by applying the composition according to claim 1 on the substrate and curing such composition.

12. The greaseproof article according to claim 11 wherein the substrate is made of paper, acrylic material, polyethylene terephthalate or plastics/paper laminate.

13. The greaseproof article according to claim 12 wherein the article is in the form of a sheet, bag or container.

14. The greaseproof article according to claim 12 wherein the article is used for food packaging.

15. The greaseproof article according to claim 12 wherein the coating has a silicon coat weight of maximum 4 g/m.sup.2.

16. A process of forming a coating on a substrate using the composition according to claim 1.

17. The process according to claim 16 wherein the composition is cured at a temperature comprised between 80 and 180 C.

18. A process for the preparation of a coating composition according to claim 1 wherein at least one of components (A), (B) and (C) is emulsified in one or more oil-in-water emulsions, and component (D) is dissolved or dispersed in water in one of the emulsions or as a separate part so that the components (A), (B), (C) and (D) are mixed together, and cured to form a coating.

19. A method comprising: applying the composition of claim 1 on a substrate, curing the composition to form a coating, wherein the coating provides at least one of the following properties greaseproof ness, food release, anti-adhesive release, air barrier, waterproofness, gas, water vapour barrier, and printability.

Description

DESCRIPTION OF EXAMPLES

(1) EVOH Solution Preparation (Examples of Organic Copolymer (D)):

(2) An ethylene-vinyl alcohol copolymer EVOH solution was prepared by dispersing EVOH in water. The solution was heated up to 95 C. under stirring until full dissolution and then cooled down. Alcohol could be added to promote fast dissolution as necessary. A 10 to 50 wt % EVOH solution was prepared and was stable upon storage conditions. Alternatively EVOH solution was pre-reacted with Octenyl Succinic Anhydride OSA or simply mixed to form a 10 wt % EVOH/OSA solution. Examples of ethylene-vinyl alcohol copolymer EVOH were Kuraray Exceval RS-1113, RS-1713, RS-1717, RS-2117, RS-2817, RS-4101, HR-3010 or AQ-4104 upon the paper application targeted e.g. food wrapping and/or food baking.

(3) Silicone-Emulsion Coating Bath Preparation:

(4) A curable organopolysiloxane Emulsion (I) containing vinyl-functional polydimethylsiloxane, poly(methylhydrogensiloxane), surfactants and water was mixed with a curable organopolysiloxane Emulsion (II) containing vinyl-functional polydimethylsiloxane, Pt-based hydrosilylation catalyst, polymerization inhibiting agent, surfactants and water in a typical A:B ratio of 80:20 to 97:3. Emulsions (I) was selected from e.g. Dow Corning Syl-Off 7920, 7950, 7976, 7978, 7990 and Emulsion (II) from e.g. Dow Corning Syl-Off 7922, 7923, 7924, 7975. Antifoam such as Dow Corning Syl-Off EM 7989 was also added. The emulsion blend was further diluted with water to reach a silicone content from 3 to 50 wt % and more often from 10 to 20 wt %.

(5) Paper Coating Process Conditions:

(6) The coating emulsion was applied with a bench top rotary printing and coating machine called The Rotary Koater from RK print-Coat Instrument Ltd. This equipment was able to coat 30 cm wide up to 120 g/m.sup.2 paper roll with various coating heads and coating rolls types. A plain roll was preferred for the examples described below and the paper speed was set at 7 m/minutes to get silicone coat weight of 0.05 to 5.0 g/m.sup.2. The coating was cured and dried in-line with an oven at 120 to 180 C. The coated paper was cut in sheets and tested for a large set of tests: silicon coat weight, water resistance or Cobb, grease resistance or KIT or NFA, bakery release, Anchorage or abrasion resistance, air permeability or gas barrier, printability.

Comparative Examples C1-C3

(7) Comparative example C1 was a surface untreated standard paper used as the substrate in the manufacturing of food packaging such as for bakery paper application.

(8) Comparative example C2 was a commercially available fluoroalkyl-treated paper from Krpa Paper.

(9) Comparative example C3 was a commercially available chromate-treated paper of Quilon type.

Comparative Examples C4-C7

(10) 200 g of the silicone-coating bath was prepared by mixing 14 g to 57 g of Emulsion (I), 0.75 g to 3 g Emulsion (II), 0.1 g antifoam emulsion and completed with tap water. The coating bath was mixed with an impeller at low speed for 5 min. It was allowed to stand for another 15 minutes prior to the coating step. The coating was applied to an uncoated paper referred as C1, cured and dried as per the process conditions described above.

Comparative Examples C8-C11

(11) 200 g of EVOH-coating bath was prepared by mixing 40 g to 120 g of an EVOH solution at 10 to 15%, diluted and mixed with tap water with an impeller at low speed for 5 min. It was allowed to stand for another 15 minutes prior to the coating step. The coating was applied to uncoated paper referred as C1, cured and dried as per the process conditions described above.

(12) An antifoam emulsion may typically be present to avoid foaming in the coating bath, but it is not a mandatory ingredient for the purpose of the invention. That is, the antifoam emulsion is not contributing to the technical solution provided by the present invention.

Examples 1 to 18: Silicone+EVOH Coating Bath

(13) 200 g of a coating bath made of a combination of silicone emulsion and EVOH was prepared by mixing 40 g to 120 g of an EVOH solution at 10 to 15%, 14 g to 57 g Emulsion (I), 0.75 g to 3 g Emulsion (II), 0.1 g antifoam emulsion and completed with tap water. The coating bath was mixed with an impeller at low speed for 5 min. It was allowed to stand for another 15 minutes prior to the coating step. The coating was applied to uncoated paper referred to as C1, cured and dried as per the process conditions described above.

(14) The respective final % wt of silicone and EVOH in the aqueous composition are indicated in the Tables 2-6 below.

(15) Details of preparation baths of Examples 6, 9 and 14 is provided here below in Table A. The other Examples were prepared in a similar manner, with the amounts adapted to account for the desired percentage by weight of silicone and EVOH in the various compositions, as disclosed in Tables 2-6 below.

(16) TABLE-US-00001 TABLE A Amounts in grams Example 6 - Example 9 - Example 14 - Si/EVOH-coated Si/EVOH-coated Si/EVOH-coated paper (Si 8%- paper (Si 2%- paper (Si 12%- RS1717 8%) RS2117 6%) HR3010 5%) Emulsion (I) 38.0 9.5 57.0 Emulsion (II) 2.0 0.5 3.0 Antifoam 0.1 0.1 0.1 emulsion EVOH 106.67 (solution 120 (solution 100.0 (solution @ 15%) @ 10%) @ 10%) Water 53.23 69.9 39.9 Total (g) 200 200 200

Examples 19 to 22: Silicone+OSA-EVOH Coating Bath

(17) 200 g coating bath made of a combination of silicone emulsion and EVO/OSA additives was prepared by mixing: 40 g to 120 g of an EVOH-OSA solution at 10 to 15%, 14 g to 57 g Emulsion (I), 0.75 g to 3 g Emulsion (II), 0.1 g antifoam emulsion and completed with tap water. The coating bath was mixed with an impeller at low speed for 5 min. It was allowed to stand for another 15 minutes prior to the coating step. The coating was applied to uncoated paper referred to as C1, cured and dried as per the process conditions described above.

(18) The respective final % wt of silicone and EVOH in the aqueous composition are indicated in the Tables 2-6 below.

Comparative Examples C12, and C13 and Example 23: PVA Comparison to EVOH

(19) Comparative example C12 is a repeat of Comparative example C5.

(20) Comparative example C13: 200 g of a coating bath made of a combination of silicone emulsion and PolyVinylAlcohol (also called PVA or PVOH) was prepared by mixing 40 g to 120 g of a PVA solution at 10 to 15%, 14 g to 57 g Emulsion (I), 0.75 g to 3 g Emulsion (II), 0.1 g antifoam emulsion and completed with tap water. The coating bath was mixed with an impeller at low speed for 5 min. It was allowed to stand for another 15 minutes prior to the coating step. The coating was applied to uncoated paper referred as C1, cured and dried as per the process conditions described above.

(21) Example 23: 200 g of a coating bath made of a combination of silicone emulsion and EVOH was prepared by mixing 40 g to 120 g of an EVOH solution at 10 to 15%, 14 g to 57 g Emulsion (I), 0.75 g to 3 g Emulsion (II), 0.1 g antifoam emulsion and completed with tap water. The coating bath was mixed with an impeller at low speed for 5 min. It was allowed to stand for another 15 minutes prior to the coating step. The coating was applied to uncoated paper referred to as C1, cured and dried as per the process conditions described above.

(22) Results:

(23) Comparative examples C1-C7 in Table 1: Blank paper vs. fluoroalkyl- or chromate- or silicone-treated papers.

(24) TABLE-US-00002 TABLE 1 Si coat KIT NFA Bakery Example weight Cobb test test release # Description (g/m.sup.2) (g/m.sup.2) number number (g/m.sup.2) C1 Uncoated 0 22.2 0 0 77.8 paper C2 Fluoroalkyl- 0 27.1 12 4 80.0 coated paper.sup.1 C3 Chromate- 0 16.9 12 1 71.5 coated paper.sup.2 C4 Silicone- 0.17 14.1 1 0 24.0 coated paper C5 Silicone- 0.19 13.5 0 0 23.6 coated paper C6 Silicone- 0.31 13.3 1 0 18.8 coated paper C7 Silicone- 0.71 10.6 0 0 7.9 coated paper .sup.1commercially available from Krpa Paper, .sup.2commercially available Quilon-type paper.

(25) The performance data reported in Table 1 indicate that a blank uncoated paper (C1) had a low water resistance, no grease barrier and a poor bakery release or baking resistance. Fluoroalkyls- or chromate-treated paper (C2 and C3, respectively) led to a slight water barrier improvement or decay and in both cases to significant grease barrier improvement and maintained poor baking resistance. Paper surface treatment with silicones led to improved water and baking resistances but no grease barrier (C4 to C7).

Examples 1-15Table 2

(26) Papers treated with Si emulsion combined with different ethylene vinyl alcohol copolymers (EVOH) and at various coat weight and dosages were prepared and evaluated, as listed in Table 2.

(27) TABLE-US-00003 TABLE 2 Si coat KIT NFA Bakery Example Description (% of Silicone and EVOH weight Cobb test test release # (with grade) in the final coating bath) (g/m.sup.2) (g/m.sup.2) number number (g/m.sup.2) C1 Uncoated paper 0 22.2 0 0 77.8 C2 Fluoroalkyl-coated paper 0 27.1 12 4 80.0 C3 Chromate-coated paper 0 16.9 12 1 71.5 C4 Silicone-coated paper 0.17 14.1 1 0 24.0 C5 Silicone-coated paper 0.19 13.5 0 0 23.6 C6 Silicone-coated paper 0.31 13.3 1 0 18.8 C7 Silicone-coated paper 0.71 10.6 0 0 7.9 C8 EVOH-coated paper (RS1717 6%) 0 23.3 0 2 70.1 5 Si/EVOH-coated paper (Si 8%-RS1717 4%) 0.22 20.3 7 0 72.9 1 Si/EVOH-coated paper (Si 8%-RS1717 6%) 0.34 20.2 9 1 73.7 6 Si/EVOH-coated paper (Si 8%-RS1717 8%) 0.55 19.2 9 3 61.4 C9 EVOH-coated paper (RS2117 6%) 0 22.1 7 1 56.1 7 Si/EVOH-coated paper (Si 8%-RS2117 4%) 0.23 15.4 8 1 60.9 8 Si/EVOH-coated paper (Si 2%-RS2117 5%) 0.05 22.8 8 2 71.6 9 Si/EVOH-coated paper (Si 2%-RS2117 6%) 0.07 21.7 10 2 69.6 10 Si/EVOH-coated paper (Si 3%-RS2117 6%) 0.17 20.6 12 2 72.0 2 Si/EVOH-coated paper (Si 6%-RS2117 6%) 0.39 18.6 12 7 / 11 Si/EVOH-coated paper (Si 9%-RS2117 6%) 0.46 12.8 11 8 33.7 C10 EVOH-coated paper (RS2817 6%) 0 21.9 6 1 72.6 12 Si/EVOH-coated paper (Si 8%-RS2817 4%) 0.23 16.1 6 1 59.9 3 Si/EVOH-coated paper (Si 8%-RS2817 6%) 0.38 16.3 10 2 52.5 13 Si/EVOH-coated paper (Si 8%-RS2817 8%) 0.61 15.5 12 4 55.0 C11 EVOH-coated paper (HR3010 6%) 0 20.0 4 2 / 14 Si/EVOH-coated paper (Si 12%-HR3010 5%) 0.30 14.8 8 1 55.9 4 Si/EVOH-coated paper (Si 8%-HR3010 6%) 0.24 14.3 8 1 51.3 15 Si/EVOH-coated paper (Si 8%-HR3010 8%) 0.36 12.5 9 3 39.8

(28) The dosage of silicone (Si) in combination with EVOH were expressed in wt % in the diluted bath before coating.

(29) The performance data reported in Table 2 indicate that Silicone-treated papers had improved water and baking resistance but very low grease barrier (C4 to C7). EVOH-treated papers led to some grease barrier improvement but at the expense of water and baking resistance (C8 to C11). The best compromise was obtained for the combination of silicone and EVOH-treated paper for which superior grease barrier was measured compared to papers treated with either silicones or EVOH, baking resistance was averaged and a good water resistance was maintained (Examples 1 to 15). Grease barrier for Examples 2 or 11 was even higher and bakery release significantly improved compared to fluoroalkyl- or chromate-treated paper references (C2 and C3, respectively) with higher water resistance for Example 11 compared to silicone-coated paper at same coat weight.

(30) Examples 1, 3, 5, 6, 16-21: Papers treated with Si emulsions combined with EVOH or with EVOH and octenyl succinic anhydride (OSA) were prepared and evaluated for Abrasion resistance, as listed in Table 3.

(31) TABLE-US-00004 TABLE 3 Si coat Bakery Example Description (% of Silicone and EVOH weight Cobb KIT test release Anchorage # (with grade) in the final coating bath) (g/m.sup.2) (g/m.sup.2) number (g/m.sup.2) (% C1 Uncoated paper 0 22.2 0 77.8 N/A C6 Silicone-coated paper 0.31 13.3 1 18.8 88.8 C7 Silicone-coated paper 0.71 10.6 0 7.9 89.5 C8 EVOH-coated paper (RS1717 6%) 0 23.3 0 70.1 N/A 5 Si/EVOH-coated paper (Si 8%-RS1717 4%) 0.22 20.3 7 72.9 92.8 1 Si/EVOH-coated paper (Si 8%-RS1717 6%) 0.34 20.2 9 73.7 93.2 6 Si/EVOH-coated paper (Si 8%-RS1717 8%) 0.55 19.2 9 61.4 94.2 C9 EVOH-coated paper (RS2117 6%) 0 22.1 7 56.1 N/A 16 Si/EVOH-coated paper (Si 6% RS2117 6%) 0.25 15.5 7 46.1 92.0 17 Si/EVOH-coated paper (Si 9% RS2117 6%) 0.65 16.4 12 42.6 91.1 18 Si/EVOH-coated paper (Si 8% RS2117 8%) 0.68 13.9 12 53.0 94.1 C10 EVOH-coated paper (RS2817 6%) 0 21.9 6 72.6 N/A 3 Si/EVOH-coated paper (Si 8% RS2817 6%) 0.38 16.3 10 52.5 92.0 13 Si/EVOH-coated paper (Si 8% RS2817 8%) 0.61 15.5 12 55.0 94.4 19 Si/EVOH/OSA-coated paper (Si 8% RS2117 8%) 0.38 14.6 10 44.7 92.5 20 Si/EVOH/OSA-coated paper (Si 12% RS2117 6%) 1.12 9.3 10 4.5 93.0 21 Si/EVOH/OSA-coated paper (Si 12% RS2117 8%) 2.00 12.5 9 5.2 97.0

(32) The performance data reported in Table 3 indicate that whichever the silicone coat weight from below 0.3 to above 2 g/m.sup.2, and the dosing of Si emulsion in combination with EVOH or EVOH/OSA, the anchorage of the coating or resistance to abrasion was superior to the reference silicone-coated paper (C6 and C7) leading to a good surface coverage and homogeneity and a superior resistance to dust formation as often observed at industrial scale processes. Moreover, the use of e.g. OSA co-additives enabled further water barrier improvement as well as significantly improved bakery release with baking residues below 10 g/m.sup.2 while maintaining high grease resistance.

(33) Examples 9, 10, 19, 20, 22: Papers treated with Si emulsions combined with EVOH or with EVOH and octenyl succinic anhydride (OSA) were prepared and evaluated for Air permeability, as listed in Table 4.

(34) TABLE-US-00005 TABLE 4 Si coat KIT NFA Bakery Air Example Description (% of Silicone and EVOH weight Cobb test test release permeability # (with grade) in the final coating bath) (g/m.sup.2) (g/m.sup.2) number number (g/m.sup.2) (Gurley) C1 Uncoated paper 0 22.2 0 0 77.8 1,042 C2 Fluoroalkyl-coated paper 0 27.1 12 4 80.0 >45,000 C3 Chromate-coated paper 0 16.9 12 1 71.5 703 C6 Silicone-coated paper 0.31 13.3 1 0 18.8 1,099 C7 Silicone-coated paper 0.71 10.6 0 0 7.9 1,200 19 Si/EVOH-coated paper (Si 12% RS2117 3%) 0.36 15.3 5 1 56.7 4,223 9 Si/EVOH-coated paper (Si 2% RS2117 6%) 0.07 21.7 10 2 69.6 16,667 10 Si/EVOH-coated paper (Si 3% RS2117 6%) 0.17 20.6 12 2 72.0 22,333 22 Si/EVOH/OSA-coated paper (Si 12% RS2117 4%) 0.66 12.8 7 1 31.4 29,667 20 Si/EVOH/OSA-coated paper (Si 12% RS2117 6%) 1.12 9.3 10 3 4.5 >45,000

(35) The performance data reported in Table 4 indicate that uncoated paper and silicone-treated papers whichever the thickness had a low air permeability (C1-C3 and C6-C7). Silicone and EVOH-treatment of papers led to a large increase in Gurley meaning a reduction of the air permeability of the surface treated paper (Examples 9, 10, 19, 20, 22). The best compromise in performances were obtained for papers treated with silicone, EVOH and OSA where grease, water and baking resistance were very high and the air permeability was so low that it was beyond the detection limit of the equipment (>45,000 GurleyExample 20). As such gas barrier was very much improved.

(36) Examples 1, 2, 5, 6: Papers treated with Si emulsions combined with EVOH were prepared and evaluated for Printability, as listed in Table 5.

(37) TABLE-US-00006 TABLE 5 Description (% of Silicone and EVOH Si coat Example (with grade) in the weight Cobb KIT test NFA test Pen # final coating bath) (g/m.sup.2) (g/m.sup.2) number number printing C1 Uncoated paper 0 22.2 0 0 Excellent C2 Fluoroalkyl-coated 0 27.1 12 4 Good paper C3 Chromate-coated 0 16.9 12 1 Excellent paper C7 silicone coated paper 0.71 10.6 0 0 Poor C8 EVOH-coated paper 0 23.3 0 2 Excellent (RS1717-6%) C9 EVOH-coated paper 0 22.1 6 0 Excellent (RS2117-6%) C10 EVOH-coated paper 0 21.9 6 1 Excellent (RS2817-6%) C11 EVOH-coated paper 0 20.0 4 2 Excellent (HR3010-6%) 1 Si/EVOH Coated paper 0.34 20.2 9 1 Good (Si 8%/RS1717 6%) 2 Si/EVOH Coated paper 0.39 18.6 12 7 Poor* (Si 6%/RS2117 6%) 5 Si/EVOH Coated paper 0.22 20.3 7 0 Excellent (Si 8%/RS1717 4%) 6 Si/EVOH Coated paper 0.55 19.2 9 3 Good (Si 8%/RS1717 8%) *DTG printing being good though.

(38) The performance data reported in Table 5 indicate that the marker pen printing was expectedly good to excellent for Comparative examples C1-C3 and C8-C11 and poor for silicone-coated paper C7. However, the printability was significantly improved up to excellent by coating a combination of silicone-emulsion with EVOH additives (Examples 1, 2, 5 and 6). Furthermore the DTG printing was good for Example 2 while grease barrier was high.

(39) Comparison was made between papers treated with PVA based compositions (C13) and EVOH based compositions (Example 23), as listed in Table 6.

(40) TABLE-US-00007 TABLE 6 Description (% of Silicone, PVA and EVOH (with grade) Si coat KIT NFA Release Example in the final coating weight Cobb test test force # bath) (g/m.sup.2) (g/m.sup.2) number number cN/inch C1 Uncoated paper 0 22.2 0 0 N.A.* C12 Silicone-coated 0.22 14.8 0 0 28.8 paper C13 Si/PVA-coated paper 0.25 21.9 9 1 67.8 (Si 6% PVA 6%) 23 Si/EVOH-coated 0.30 15.2 12 2 35.1 paper (Si 6%-EVOH RS2117 6%) *the release force could not be measured since the paper was torn apart during the test and the force value was beyond the maximum force value of the equipment.

(41) The performance data reported in Table 6 indicate that the silicone-coated paper (C12) provides both very good water resistance (low Cobb value) and release (low release force) performances compared to uncoated paper (C1). In the contrary and although Si/PVA coated paper provides some but insufficient grease barrier (C13), the addition of PVA is both detrimental for water resistance and release performances and annihilates the performance benefits observed for silicone-coated paper over the uncoated paper. Si/EVOH-coated paper (Example 23) provides the optimum performances benefits over the silicone- or silicone/PVA-coated papers (C12 and C13, respectively). The grease barrier is very high for the Kit test at maximum test scale of 12. The grease barrier by the NFA test is further improved while the water resistance and release performances remain superior and in the range required by the industry for premium grade grease/water barrier and low release force thus low food residues quality paper.