Cellulose fiber-based substrate, its manufacturing process and use as masking tape

1. An adhesive tape comprising:

(i) a cellulose fiber-based paper substrate,

(ii) a release coating layer on at least one surface of the paper substrate, and

(iii) an adhesive layer on another surface of the paper substrate opposite to the release coating layer, wherein

the release coating layer comprises a reaction product from an aqueous mixture comprised of, based on dry weight percentage:

(a) 50-99% of at least one water-soluble polymer (WSP) containing hydroxyl groups,

(b) 1-50% of at least one diketene compound, wherein the at least one diketene compound is substituted with at least one linear, branched and/or cyclic C 8 -C 30 hydrocarbon chain which may contain heteroatoms, and

(c) at least one crosslinking agent,

wherein the at least one diketene compound is immobilized on the WSP and the WSP is immobilized on the at least one surface of the paper substrate.

2. The adhesive tape according to claim 1 , wherein the paper substrate is crepe paper.

3. The adhesive tape according to claim 2 , wherein the adhesive tape is a masking tape.

4. The adhesive tape to claim 1 , wherein the water-soluble polymer (WSP) containing hydroxyl groups is selected from the group consisting of polyvinyl alcohol (PVA); starch; oxidized starch; esterified starch; etherified starch; vinyl acetate copolymers, ethylene-vinyl acetate copolymers, vinyl chloride-vinyl acetate copolymers, N-vinylpyrrolidone-vinyl acetate copolymers, maleic anhydride-vinyl acetate copolymers; vinyl acetate.

5. The adhesive tape according to claim 4 , wherein the WSP is a hydrolyzed or partially hydrolyzed ethylene-vinyl acetate (EVA) copolymer or a hydrolyzed or partially hydrolyzed vinyl chloride-vinyl acetate copolymer.

6. The adhesive tape according to claim 1 , wherein the at least one diketene compound comprises a diketene molecule of the following structure:

wherein R 1 and R 2 are independent linear or branched and/or cyclic C 8 -C 30 hydrocarbon chains which may contain heteroatoms.

7. The adhesive tape according to claim 1 , wherein the crosslinking agent is selected from the group consisting of CHO—Y—CHO where Y is a linear or branched hydrocarbon chain and/or a cyclic molecule which may contain heteroatoms, polyaldehydes, polyisocyanates, and adipic acid/epoxypropyl diethylenetriamine copolymer.

8. The adhesive tape according to claim 1 , wherein

(a) the at least one water-soluble polymer (WSP) is polyvinyl alcohol (PVA),

(b) the at least one diketene compound is at least one alkylated diketene compound having the following structure:

 wherein

R 1 is selected from the group consisting of tetradecyl (C 14 ), hexadecyl (C 16 ) and octadecyl (C 18 ), and R 2 is selected from the group consisting of tetradecyl (C 14 ), hexadecyl (C 16 ) and octadecyl (C 18 ), and

(c) the at least one crosslinking agent is glyoxal.

9. The adhesive tape according to claim 1 , wherein the coating composition comprises, based on dry weight percentage, between 1 and 20% of the at least crosslinking agent.

10. The adhesive tape according to claim 9 , wherein the release coating layer comprises, based on a dry weight percentage:

(a) between 60 and 90% of the water-soluble polymer (WSP),

(b) between 10 and 40% of the at least one diketene compound, and

(c) between 3 and 15% of the crosslinking agent.

11. The adhesive tape according to claim 1 , wherein the coating composition of the release coating layer is present in the adhesive tape in an amount between 1 and 20 g/m 2 based on a dry basis weight.

12. The adhesive tape according to claim 11 , wherein the release coating layer is present in an amount between 3 and 10 g/m 2 based on the dry basis weight.

13. A method of producing the adhesive tape according to claim 1 which comprises the steps of:

(1) forming the cellulose fiber-based paper substrate;

(2) forming the reaction product from the aqueous mixture comprising, based on dry weight percentage:

(a) 50-99% of the at least one water-soluble polymer (WSP) containing hydroxyl groups,

(b) 1-50% of the at least one diketene compound substituted with at least one linear or branched and/or cyclic C 8 -C 30 hydrocarbon chain which may contain heteroatoms, and

(c) the at least one crosslinking agent;

(3) coating the at least one surface of the paper substrate with the reaction product,

(4) drying the coating on the at least one surface of the paper substrate to form the release coating layer, and

(5) applying the adhesive layer onto another surface of the coated substrate opposite to the release coating layer.

14. The method of claim 13 , wherein the at least one water-soluble polymer containing hydroxyl groups comprises polyvinyl alcohol, wherein the at least one diketene compound comprises alkyl ketene dimer, and wherein the release coating layer comprises from 50-70 parts of the polyvinyl alcohol to 30-50 parts of the alkyl ketene dimer.

15. The adhesive tape of claim 1 , wherein the release coating layer comprises from 50-70 parts of the at least one water-soluble compound to 30-50 parts of the at least one diketene compound.

16. The adhesive tape of claim 15 , wherein the at least one water soluble compound comprises polyvinyl alcohol or starch, and wherein the at least one diketene compound comprises alkyl ketene dimer.

17. The adhesive tape of claim 1 , wherein the at least one water-soluble polymer containing hydroxyl groups comprises polyvinyl alcohol, wherein the at least one diketene compound comprises alkyl ketene dimer, and wherein the release coating layer comprises from 50-70 parts of the polyvinyl alcohol to 30-50 parts of the alkyl ketene dimer.