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

Abstract

A cellulose fiber-based substrate, at least one side of which is coated with an aqueous mixture composed of: a) at least one water-soluble polymer (WSP) containing hydroxyl groups, b) at least one lactone substituted with at least one linear or branched and/or cyclic C.sub.8-C.sub.30 hydrocarbon chain which may contain heteroatoms, c) at least one crosslinking agent. A method of production and use thereof.

Claims

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.sub.8-C.sub.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: ##STR00004## wherein R.sup.1 and R.sup.2 are independent linear or branched and/or cyclic C.sub.8-C.sub.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 CHOYCHO 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: ##STR00005## wherein R.sup.1 is selected from the group consisting of tetradecyl (C.sub.14), hexadecyl (C.sub.16) and octadecyl (C.sub.18), and R.sup.2 is selected from the group consisting of tetradecyl (C.sub.14), hexadecyl (C.sub.16) and octadecyl (C.sub.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.sup.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.sup.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.sub.8-C.sub.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.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention and advantages thereof will become more apparent from the following non-limiting examples given to describe the invention.

(2) FIG. 1 illustrates a paint test to see the resistance of masking tape against paint for a 1.sup.st sample.

(3) FIG. 2: illustrates a paint test to see the resistance of masking tape against paint for a 2.sup.d sample sample.

(4) FIG. 3 illustrates a paint test to see the resistance of masking tape against paint for a 3.sup.d sample.

EMBODIMENTS OF THE INVENTION

I/1.SUP.st .Embodiment: Crepe Paper as a Substrate

(5) 1: Comparative Test:

(6) A sheet of crepe paper for masking tape (Master Tape Classic 100) with a basis weight of 39 g/m.sup.2 was treated on one side by being coated with an aqueous mixture with a dry weight of 5 g/m.sup.2 obtained according to the invention.

(7) The composition by dry weight was composed of: 46% dry Celvol 28/99 (or 46% starch Perfectamyl A4692), 46% dry AKD (Aquapel J215 by Ashland) 8% Glyoxal (TSI Cartabond by Clariant).

(8) The resulting paper had a basis weight of 44 g/m.sup.2.

(9) This paper was compared with crepe paper of the same type (100/39 g/m.sup.2 Master Tape Classic) treated with an SBR-type of latex (XZ 97235.00 by Styron) and with a 4 g/m.sup.2 acrylic release agent (Primal R-550 by Dow).

(10) The following comparative table summarizes the mechanical properties that were measured under dry and wet conditions and shows the results:

(11) TABLE-US-00001 39 g/m.sup.2 Master Invention: tape 100 + 10 39 g/m.sup.2 Master g/m.sup.2 SBR-type tape 100 + 5 g/m.sup.2 latex + 4 g/m.sup.2 PVA + AKD + acrylic release Glyoxal agent Basis weight (g/m.sup.2) 44 53 dry MD tensile strength 2.37-11.6 2.72-13 (kN/m) - elongation (%) dry CD tensile strength (kN/m) 1.23 1.22 wet MD tensile strength (kN/m) 1.2 1.32 wet CD tensile strength (kN/m) 0.59 0.5 60 sec Cobb (g/m.sup.2) 13 12 Release strength (N/5 cm) 5.8 7.6
2: Release Test:

(12) A sheet of 60 g/m.sup.2 crepe paper was coated with various aqueous compositions using size press treatment. The dry deposition of these compositions was between 6 and 7 g/m.sup.2.

(13) The aqueous compositions included: PVA (Moviol 4/98) (or starch Perfectamyl A4692), AKD (AquaperJ215 by Ashland) Glyoxal (CAS No. 107-22-2) (Cartabond TSI by Clariant) Water.

(14) The FINAT FTM 1 test was applied. This test assesses the adaptation of a release substrate to rolling by using a PSA-type adhesive.

(15) Sample 1: A piece of a commercial masking tape (COTEKA of Bricomarche, 5 cm width) was applied onto the release face of another piece of COTEKA tape using a 10 kg roller. The peel strengths were measured at a speed of 300 mm/min and an angle of 180.

(16) PVA/AKD70/30 sample: A piece of commercial masking tape (COTEKA by Bricomarch, 5 cm width) was applied using a 10 kg roller on the side of a piece of crepe paper coated with the composition of the invention composed of 70 parts PVA to 30 parts AKD (or 64.4% PVA, 27.6% AKD, and 8% glyoxal by weight).

(17) PVA/AKD60/40 sample: A piece of commercial masking tape (COTEKA by Bricomarch, 5 cm width) was applied using a 10 kg roller on the side of a piece of crepe paper coated with the composition of the invention composed of 60 parts PVA to 40 parts AKD (or 55.2% PVA, 36.8% AKD, and 8% glyoxal by weight).

(18) PVA/AKD50/50 sample: A piece of commercial masking tape (COTEKA by Bricomarch, 5 cm width) was applied using a 10 kg roller on the side of a piece of crepe paper coated with the composition of the invention composed of 50 parts PVA to 50 parts AKD (or 46% PVA, 46% AKD and 8% glyoxal, by weight).

(19) TABLE-US-00002 Standard separation strength Release strength (N/5 cm) Sample 1 (COTEKA) 7.24 PVA/AKD - 70/30 sample 8.26 PVA/AKD - 60/40 sample 7.08 PVA/AKD - 50/50 sample 5.87

(20) It was noted that the peel strengths of the invention were on par with those of the commercial product, between 5 to 8 N/5 cm, and they varied according to the amount of AKD introduced into the mixture. The greater the amount of AKD in the mixture, the lower the peel strength. This shows the release property of the alkyl chains present within the AKD.

(21) 3: FINAT FTM 11 TestSubsequent Adhesion:

(22) The subsequent adhesion release is the force required at a given speed and angle to tear a tape coated with an adhesive adhered to a standard test plate, this tape having previously been in contact with the side of a substrate of the same type coated with a release agent under specific temperature and humidity conditions.

(23) The aim of this test is to measure the possible transfer of the release agent into the adhesive layer.

(24) The percentage of subsequent adhesion is expressed as the ratio between the measured adhesion compared with the adhesion obtained by a similar control tape which was not in contact with a substrate coated with a release agent. The adhesion value of the control tape was measured at 10.97 N/5 cm.

(25) TABLE-US-00003 Subsequent separation Separation strength strength (N/5 cm) % Loss/Gain Sample 1 (COTEKA) 10.52 4.1% PVA/AKD - 70/30 sample 10.43 4.9% PVA/AKD - 60/40 sample 10.45 4.7% PVA/AKD - 50/50 sample 9.91 9.6%

(26) The amount of loss of adhesion strength of substrates related to the invention was similar to the commercial product. There is therefore little or no transfer of AKD into the adhesive.

(27) 4: Peel Strength After Pressure Aging Test (70 g/cm.sup.2) at Room Temperature in Accordance with the FINAT FM 10 Test:

(28) A commercial masking tape (COTEKA by Bricomarche, 5 cm width) was applied on the different types of crepe paper and COTEKA tapes using a 10 kg roller under the same conditions as Example 2. The samples were pressurized (70 g/cm.sup.2) at room temperature (23 C. and 50% humidity) for 20 hours. They were then kept for at least 4 hours at 23 C. and 50% relative humidity. The peel strengths were measured at a speed of 300 mm/min and an angle of 180FINAT FM1 test.

(29) TABLE-US-00004 Standard separation Separation strength strength (N/5 cm) Aver- % Loss/ Sample 1 2 3 age Gain Sample 1 (COTEKA) 7.12 7.23 6.88 7.08 2.26 PVA/AKD - 70/30 sample 7.57 7.31 7.56 7.48 9.41 PVA/AKD - 60/40 sample 7.67 6.78 6.72 7.06 0.28 PVA/AKD - 50/50 sample 5.63 5.63 5.88 5.71 2.61

(30) The values were compared with the values of Example 2 (Separation strength before the aging test). It was noted that the change in strength of both the commercial product and the substrate of the invention was low (loss between 2 and 9%) and therefore the peel strengths were stable over time under pressure at room temperature.

(31) 5: FINAT FTM 11 TestSubsequent Adhesion After Aging at Room Temperature:

(32) Subsequent adhesion release is the force at a given speed and angle required to tear a tape coated with an adhesive adhered to a standard test plate, this tape having previously been in contact with the side of a substrate of the same type coated with a release agent under specific temperature and humidity conditions.

(33) The percentage of subsequent adhesion is expressed as the ratio between the adhesion measured compared to the adhesion obtained by a similar control tape which was not in contact with a substrate coated with a release agent. The adhesion value of the control tape was measured at 10.97 N/5 cm.

(34) TABLE-US-00005 Release strength (N/5 cm) % Loss/Gain Sample 1 (COTEKA) 10.02 8.6 PVA/AKD - 70/30 sample 10.41 5.1 PVA/AKD - 60/40 sample 9.84 10.3 PVA/AKD - 50/50 sample 9.41 14.22

(35) The amount of loss of adhesion strength of substrates related to the invention was similar to the commercial product. There is therefore little or no transfer of AKD into the adhesive. The prototype with 50 parts of AKD shows a lower value, involving a slight potential migration of AKD into the adhesive.

(36) 6: Peel Strength After Pressure Aging Test (70 g/cm.sup.2) at 70 C. in Accordance with the FINAT FM 10 Test:

(37) A commercial masking tape (COTEKA by Bricomarch, 5 cm width) was applied on the different types of crepe paper and COTEKA tapes using a 10 kg roller under the same conditions as Example 2. The samples were pressurized (70 g/cm.sup.2) at 70 C. for 20 hours. They were then kept for at least 4 hours at 23 C. and 50% relative humidity. The peel strengths were measured at a speed of 300 mm/min and an angle of 180FINAT FM1 test.

(38) TABLE-US-00006 Standard release Release strength (N/5 cm) % Loss/Gain Sample 1 (COTEKA) 8.26 14.09 PVA/AKD - 70/30 sample 9.89 19.78 PVA/AKD - 60/40 sample 10.68 50.92 PVA/AKD - 50/50 sample 9.11 55.28

(39) The change in the peel strengths of the substrate of the invention with 30 parts of AKD shows a change in its release properties similar to the commercial product (15-20%). In contrast, the other two samples of the invention show quite a significant change (+50%).

(40) 7: FINAT FTM 11 TestSubsequent Adhesion After Aging at 70 C.:

(41) The subsequent adhesion release is the force required at a given speed and angle to tear a tape coated with an adhesive adhered to a standard test plate, this tape having previously been in contact with the side of a substrate of the same type coated with a release agent under specific temperature and humidity conditions.

(42) The percentage of subsequent adhesion is expressed as the ratio between the measured adhesion compared to the adhesion obtained by a similar control tape which was not in contact with a substrate coated with a release agent. The adhesion value of the control tape was measured at 10.97 N/5 cm.

(43) TABLE-US-00007 Subsequent separation Separation strength strength (N/5 cm) % Loss/Gain Sample 1 (COTEKA) 9.76 11 PVA/AKD - 70/30 sample 10.01 8.7 PVA/AKD - 60/40 sample 9.21 16 PVA/AKD - 50/50 sample 7.43 32.2

(44) The amount of loss of adhesion strength of substrates with 30 parts of AKD was similar to the commercial product. There is therefore little or no transfer of AKD into the adhesive for this prototype. In contrast, the prototype with 50 parts of AKD shows a much lower value (loss of adhesion strength of more than 30%) involving a potential migration of AKD into the adhesive.

(45) 8: Peel Strength After Aging (7 days) at High Temperature (65 C.) and High Humidity (85% Relative Humidity)AFERA #4003 (EN 12024) Test:

(46) A commercial masking tape (COTEKA by Bricomarch, 5 cm width) was applied to the different types of crepe paper of the invention and to itself using a 10 kg roller. The samples were then kept as such (without pressure) in a climate simulation chamber at 65 C. and 85% humidity for 7 days (AFERA #4003 test). The peel strengths were measured at a speed of 300 mm/min and an angle of 180.

(47) TABLE-US-00008 Sample Initial peel Peel strength (peel strength: N/5 cm) strength after aging % change Sample 1 (COTEKA) 7.24 9.99 +38% PVA/AKD - 70/30 sample 8.26 9.95 +20% PVA/AKD - 60/40 sample 7.08 9.37 +32% PVA/AKD - 50/50 sample 5.87 8.34 +42%

(48) It may therefore be noted that the different types of crepe paper of the invention perform similarly or better (more stable peel strength for the PVA/AKD70/30 mixture) than the commercial product (i.e.: COTEKA).

II/2.SUP.d .Embodiment: Flat Back Paper as a Substrate

(49) Release Test:

(50) A sheet of 62 g/m.sup.2 flat back paper was coated with various aqueous compositions using size press treatment. The dry deposition of these compositions was 8 g/m.sup.2.

(51) The aqueous compositions included: PVA (Moviol 4/98) (or starch Perfectamyl A4692), AKD (AquapelJ215 by Ashland) Glyoxal (CAS No. 107-22-2) (Cartabond TSI by Clariant) Water.

(52) The FINAT FTM 1 test was applied. This test assesses the adaptation of a release substrate to rolling by using a PSA-type adhesive.

(53) Sample 1: A piece of a commercial masking tape (COTEKA of Bricomarch, 5 cm width) was applied onto the release face of another piece of COTEKA tape using a 10 kg roller. The peel strengths were measured at a speed of 300 mm/min and an angle of 180.

(54) PVA/AKD70/30 sample: A piece of commercial masking tape (COTEKA by Bricomarch, 5 cm width) was applied using a 10 kg roller on the side of a piece of a flat back paper (AHLSTROM Mastertape DELICATE 40062 g/m.sup.2) coated with 8 g/m.sup.2 of the composition of the invention composed of 70 parts PVA to 30 parts AKD (or 64.4% PVA, 27.6% AKD, and 8% glyoxal by weight).

(55) Starch/AKD70/30 sample: A piece of commercial masking tape (COTEKA by Bricomarch, 5 cm width) was applied using a 10 kg roller on the side of a piece of a flat back paper ((AHLSTROM Mastertape DELICATE 40062 g/m.sup.2) coated with 8 g/m.sup.2 of the composition of the invention composed of 70 parts Starch to 30 parts AKD (or 64.4% starch, 27.6% AKD, and 8% glyoxal by weight).

(56) TABLE-US-00009 Standard separation strength Release strength (N/5 cm) Sample 1 (COTEKA) 7.24 PVA/AKD - 70/30 sample 6.89 Starch/AKD - 70/30 sample 5.956

(57) It was noted that the peel strengths of the invention were on par with those of the commercial product, between 5 to 8 N/5 cm. This shows the release property of the alkyl chains present in AKD.

III/Paint Test

(58) The aim of paint test is to see the resistance of masking tape against paint. Especially, the migration of the paint on the edges (paint back) is observed. This test has been developed by the Applicant.

(59) 1/Preparation of the Sample

(60) Sample 1: A commercial masking tape (COTEKA by Bricomarch, 5 cm width).

(61) Sample 2: A sheet of crepe paper for masking tape (Mastertape Smart line 300) with a basis weight of 55 g/m.sup.2 was treated by size press at machine scale with an aqueous mixture PVA/AKD (50/50 in parts or 46% PVA, 46% AKD and 8% glyoxal by weight), with a dry weight of 5 g/m.sup.2.

(62) Sample 3: A sheet of flat back paper ((AHLSTROM Mastertape DELICATE 400-62 g/m.sup.2)) with a basis weight of 62 g/m.sup.2 was treated by size press at lab scale with an aqueous mixture PVA/AKD (70/30 in parts or 64.4% PVA, 27.6% AKD and 8% glyoxal by weight), with a dry weight of 8 g/m2.

(63) Sample 2 and 3 are then coated on the smoother side with 25 to 30 g/m.sup.2 of an adhesive (DowCorning Binder ROBOND PS9005 (MS: 57%)).

(64) 2/ Application of the Paint

(65) Sample 1 and samples 2 and 3 (these later being cut in band of 5 cm width) are applied each on a 13 cm by 13 cm transparent glass plate. 3.5 to 3.7 g of paint is applied on all the surface of the plate.

(66) The plates are left to dry at least 4 hours.

(67) 3/Measurement of the Migration of the Paint

(68) Each plate is turned and a transparent mesh having holes of 1 mm is applied against the plate. Surface of migration is then calculated by counting the number of holes filed with the paint/cm. lower is the surface of paint, lower is the migration and better is the marking tape.

(69) 4/Results

(70) FIG. 1: Sample 1 corresponds to COTEKA. The migration is 10.6 mm.sup.2/cm.

(71) FIG. 2: sample 2 of the invention. The migration is 0.6 mm.sup.2/cm.

(72) FIG. 3: sample 3 of the invention. The migration is 0.12 mm.sup.2/cm.