Cellulosic fiber-based substrate, method of production and use as a substrate for adhesive tapes

Abstract

A cellulosic fiber-based adhesive tape substrate, at least one side of which is coated with an aqueous mixture of: a) at least one organic polymer having pendant groups with at least one vinyl function; b) at least one polysiloxane comprising at least one hydrogenosiloxane monomer (OSiR.sup.1H), wherein R.sup.1 is a linear or branched and/or cyclic hydrocarbon chain which may contain heteroatoms; c) at least one hydrosilylation catalyst.

Claims

1. A cellulosic fiber-based adhesive tape substrate, wherein at least one side of the substrate is directly coated with a single layer comprising an aqueous mixture of: a) at least one organic polymer comprising pendant groups with at least one vinyl function, wherin the organic polymer comprises polyvinyl alcohol; b) at least one polysiloxane comprising at least one hydrogen siloxane monomer (OSiR1H), wherein R1 is a linear or branched and/or cyclic hydrocarbon chain optionally containing heteroatoms; and c) at least one hydrosilylation catalyst; wherein the at least one polysiloxane cross-links the polyvinyl alcohol via the at least one vinyl function without or prior to any subsequent coating step.

2. The substrate according to claim 1, wherein at least some of the polyvinyl alcohol is reacted by acetylation and/or hemiacetylation with at least one organic molecule (OM1) comprising at least one aldehyde function and at least one vinyl function, and/or at least some of the polyvinyl alcohol is reacted with at least one organic molecule (OM2) comprising at least one epoxy function and at least one vinyl function.

3. The substrate according to claim 2, wherein: the molecule OM1 is a molecule with the formula HCO(R.sup.2)CHCH2, wherein R.sup.2 is a linear and/or cyclic hydrocarbon chain, which optionally contains at least one heteroatom (X); and the molecule OM2 is a molecule having the formula H.sub.2COCH(R.sup.3)CHCH2, wherein R.sup.3 is a linear, branched and/or cyclic hydrocarbon chain (C).sub.x, which optionally contains at least one heteroatom (X).

4. The substrate according to claim 1, wherein the polysiloxane is selected from the group consisting of polyhydrogenmethylsiloxane (PHMS); poly(hydrogenmethyl-co-dimethyl) siloxane (PHDMS) copolymer; cyclic-polyhydrogenomethylsiloxane; and cyclic poly(hydrogenomethyl-co-dimethyl) siloxane (PHDMS) copolymer.

5. The substrate according to claim 1, wherein: the organic polymer is obtained through the modification of polyvinyl alcohol (PVA) by undecylenic aldehyde, and the polysiloxane is polyhydrogenomethylsiloxane (PHMS).

6. The substrate according to claim 1, wherein the single layer by percent dry weight: between 70 and 98% of the organic polymer, between 1 and 20% of the polysiloxane, between 1 and 20% of the catalyst, and wherein the single layer has a ratio of SiH of the polysiloxane to vinyl functional groups of the organic polymer of between 1 and 5.

7. The substrate according to claim 6, wherein the single layer comprises by percent dry weight: between 80 and 98% of the organic polymer, between 1 and 11% of the polysiloxane, between 1 and 11% of the catalyst, and wherein a ratio of SiH of the polysiloxane to vinyl functional groups of the organic polymer of between 1 and 5.

8. The substrate according to claim 1, wherein the composition has a dry basis weight of between 1 and 10 g/m.sup.2 relative to a surface area of the substrate.

9. The substrate according to claim 1, wherein the catalyst is platinum based.

10. The substrate according to claim 1, wherein the substrate is crepe paper.

11. A masking tape which comprises the cellulosic-fiber based substrate according to claim 1.

12. A cellulosic fiber-based adhesive tape substrate comprising: a coating on a surface thereof, the coating consisting essentially of a cross-linked polyvinylalcohol comprising pendant groups with at least one vinyl function, wherein the polyvinylalcohol is cross-linked by hydrosilylation with at least one polysiloxane comprising at least one hydrogen siloxane monomer (OSiR1H), and wherein R1 is a linear or branched and/or cyclic hydrocarbon chain optionally containing heteroatoms.

13. A cellulosic fiber-based adhesive tape substrate comprising: a coating on a surface thereof, the coating consisting essentially of a cross-linked polyvinylalcohol comprising pendant groups with at least one vinyl function and at least one hydrosilylation catalyst, wherein the polyvinylalcohol is cross-linked with at least one polysiloxane comprising at least one hydrogen siloxane monomer (OSiR1H), and wherein R1 is a linear or branched and/or cyclic hydrocarbon chain optionally containing heteroatoms.

14. A method to produce the cellulosic-fiber based substrate comprising: 1) forming a substrate from an aqueous suspension of cellulosic fibers on a paper machine; 2) preparing a composition by mixing in an aqueous medium: a) at least one organic polymer comprising pendant groups with at least one vinyl function, wherein the organic polymer comprising polyvinyl alcohol; b) at least one polysiloxane comprising the at least one hydrogen siloxane monomer (OSiR1H), wherein R.sup.1 is a linear or branched and/or cyclic hydrocarbon chain which may contain heteroatoms; and c) least one hydrosilylation catalyst; 3) coating a single layer of the composition onto at least one side of the substrate, wherein the at least one polysiloxane cross-links the polyvinyl alcohol via the at least one vinyl function without or prior to any subsequent coating steps; and 4) drying the single layer of the composition coated onto the at least one side of the substrate.

Description

EMBODIMENTS OF THE INVENTION

I/ 1st Embodiment: Crepe Paper as a Substrate

(1) 1: Comparative Test

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

(3) Composition of the Mixture (COMPOSITION 1):

(4) Organic polymer=PVA.sup.1 (Celvol 28/99) modified with 5% by weight of undecenal.

(5) Polyhydrogenomethylsiloxane=Xiameter MEM 0075 at 5% by weight.

(6) Catalyst=Syl-Off 7924 at 5% by weight.

(7) .sup.1PVA modified with undecylenic aldehyde.

(8) Reaction of 100 g PVA and 5 g undecylenic aldehyde in 1 L water at pH=1.5 and T=90 C. for a duration of typically between 45 and 90 minutes. At the end of the reaction, the pH is adjusted to 7 by the addition of soda.

(9) The resulting paper is compared with crepe paper of the same type treated with 10 g/m.sup.2 SBR latex (Styron XZ 97235.00)+4 g/m.sup.2 acrylic latex with release properties (Primal R 550 from Rohm and Haas).

(10) TABLE-US-00001 Invention: Master tape 100 Master tape 100 (39 g/m.sup.2) + 10 g/m.sup.2 (39 g/m.sup.2) + of SBR latex + 10 g/m.sup.2 of 4 g/m.sup.2 of acrylic COMPOSITION 1 release agent Basis weight (g/m.sup.2) 49 53 Dry MD tensile strength 2.89-9% 2.72-13% (kN/m) elongation (%) Dry CD tensile strength 1.86 1.22 (kN/m) Wet tensile strength 1.7 1.32 (kN/m) Wet tensile strength 0.75 0.5 (kN/m) 60 sec Cobb (g/m.sup.2) 19.5 12 Cobb test

(11) 2: Release Comparison 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) Formulation 2.1:

(14) Polymer=PVA.sup.1 (Moviol 4/98) modified with 1% by weight of undecenal.

(15) Polyhydrogenomethylsiloxane=Xiameter MEM 0075 at 1% by weight (relative to the weight of PVA).

(16) Catalyst=Syl-Off 7924 at 1% by weight (relative to the weight of PVA).

(17) Formulation 2.2:

(18) Polymer=PVA.sup.1 (Moviol 4/98) modified with 2% by weight of undecenal.

(19) Polyhydrogenomethylsiloxane=Xiameter MEM 0075 at 2% by weight.

(20) Catalyst=Syl-Off 7924 at 2% by weight.

(21) Formulation 2.5:

(22) PH=PVA.sup.1 (Moviol 4/98) modified with 5% by weight of undecenal.

(23) Polyhydrogenomethylsiloxane=Xiameter MEM 0075 at 5% by weight.

(24) Catalyst=Syl-Off 7924 at 5% by weight.

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

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

(27) Sample 2.1: A piece of commercial masking tape (COTEKA from 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, formulation 2.1.

(28) Sample 2.2: A piece of commercial masking tape (COTEKA from Bricomarch, 5 cm width) was applied using a 10 kg roller onto the side of a piece of crepe paper coated with the composition of the invention, formulation 2.2.

(29) Sample 2.5: A piece of commercial masking tape (COTEKA from 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, formulation 2.5.

(30) TABLE-US-00002 Standard separation strength Separation strength (N/5 cm) Sample 1 2 3 Avg Sample 1 (COTEKA) 7.4 7.28 7.04 7.24 Sample 2.1 7.98 7.88 7.76 7.87 Sample 2.2 6.52 5.8 6.23 6.18 Sample 2.5 4.67 4.9 4.97 4.85

(31) It was noted that the peel strengths of the invention were on par with those of the commercial product, between 5 and 8 N/5 cm.

(32) 3: FINAT FTM 11 TestSubsequent Adhesion:

(33) 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.

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

(35) 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 as 10.97 N/5 cm.

(36) TABLE-US-00003 Subsequent separation strength (N/5 cm) Sample 1 2 3 Avg % Loss Sample 1 10.44 10.28 10.85 10.52 4.1% (COTEKA) Sample 2.1 10.67 11 10.24 10.64 3% Sample 2.2 9.2 9.02 10.17 9.46 13.7% Sample 2.5 10.1 10.13 10.63 10.29 6.2%

(37) It was therefore noted that the loss of adhesion, following the peel tests, was relatively low, around 4% for the commercial product. The various substrates of the invention have adhesion losses similar to a commercial product (3% for formulation 2.1).

(38) 4: Peel Strength After Aging Test Under Pressure (70 g/cm.sup.2) at Room Temperature and at 70 C. in Accordance with the FINAT FM 10 Test:

(39) At Room Temperature:

(40) A commercial masking tape (COTEKA from 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 in 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% humidity. The peel strengths were measured at a speed of 300 mm/min and an angle of 180, FINAT FM1 test.

(41) TABLE-US-00004 Separation strength after aging at room temperature Separation strength (N/5 cm) % Loss/ Sample 1 2 3 Avg Gain Sample 1 (COTEKA) 7.12 7.23 6.88 7.08 2.26 Sample 2.1 7.55 7.42 7.63 7.53 4.32 Sample 2.2 6.51 6.68 6.13 6.44 4.15 Sample 2.5 4.58 4.68 4.69 4.65 4.06

(42) The values were compared with the values of Example 2 Separation strength before the aging test). It was noted that, for both the commercial product and the substrates of the invention, the change in the strength was low (between a loss of 4% and a gain of 4%) and therefore the peel strengths were stable over time under pressure at room temperature.

(43) At 70 C.

(44) A commercial masking tape (COTEKA from 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 in Example 2. The samples were pressurized (70 g/cm.sup.2) at a temperature of 70 C. for 20 hours. They were then kept for at least 4 hours at 23 C. and 50% humidity. The peel strengths were measured at a speed of 300 mm/min and an angle of 180, FINAT FM1 test.

(45) TABLE-US-00005 Separation strength after aging at a temperature of 70 C. Separation strength (N/5 cm) % Loss/ Sample 1 2 3 Avg Gain Sample 1 8.4 7.89 8.49 8.26 14.09 (COTEKA) Sample 2.1 9.09 9.68 8.49 9.09 15.41 Sample 2.2 8.87 7.94 9.39 8.73 41.24 Sample 2.5 6.88 7.19 6.91 6.99 44.29

(46) The values were compared with the values of Example 2 (Separation strength before the aging test). It was noted that for both the commercial product and one of the substrates of the invention, there was a slight increase in the peel strength of around 15%. The two other examples of the invention had a slightly greater increase in peel strength (around 40%) but with peel values specific to masking tape (between 5 and 8 N/5 cm).

(47) 5: FINAT FTM 11 Test-Subsequent Adhesion After Aging at Room Temperature and at 70 C. (See FINAT FTM 11):

(48) 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.

(49) 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 as 10.97 N/5 cm.

(50) At Room Temperature:

(51) TABLE-US-00006 Aging at room temperature Subsequent separation strength (N/5 cm) Sample 1 2 3 Avg % Loss Sample 1 10.24 10.58 9.25 10.02 8.7% (COTEKA) Sample 2.1 9.73 9.57 10.64 9.98 9% Sample 2.2 10.19 9.8 8.66 9.55 12.9% Sample 2.5 10.52 9.88 9.77 10.06 8.3%

(52) The loss of adhesion following aging under pressure at room temperature remained low, at around 10%, with similar values for the commercial product and the substrates related to the invention.

(53) At 70 C.:

(54) TABLE-US-00007 Aging at 70 C. Subsequent separation strength (N/5 cm) Sample 1 2 3 Avg % Loss Sample 1 9.86 9.51 9.9 9.76 11% (COTEKA) Sample 2.1 9.93 10.29 9.8 10.01 8.7% Sample 2.2 10.35 8.79 9.21 9.45 13.8% Sample 2.5 9.52 8.97 9.03 9.17 16.4%

(55) The loss of adhesion following aging under pressure at 70 C. remained low, at around 10%, with similar values for the commercial product and the 10 substrates related to the invention, notably formulation 2.1.

(56) 6: Peel Strength After Aging (7 Days) at High Temperature (65 C.) and High Humidity (85% Relative Humidity)-AFERA #4003 (EN 12024) Test:

(57) Samples relating to formulations 2.1, 2.2 and 2.5 of the invention were complexed with commercial masking tape (COTEKA from Bricomarch) and conditioned for one week at 65 C. and 85% relative humidity. The commercial tape (COTEKA) was complexed in a similar way to itself and kept for one week at 65 C. and 85% relative humidity. The peel strengths were measured afterwards for at least 4 hours in a conditioning room (23 C. and 50% relative humidity) and compared with the initial peel strengths.

(58) 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% Sample 2.1 7.87 8.82 +12% Sample 2.2 6.18 8.22 +33% Sample 2.5 4.85 6.42 +32%

(59) It was noted that the change in the peel strength remained low for formulation 2.1 of the invention (+12%). The two other formulations had slightly greater increases (of around 30%), but their peel values remained in the range of values for masking tapes, i.e. between 5 and 8 N/5 cm. It was noted that the commercial sample had greater instability than the substrates of the invention vis-a-vis the aging test under high humidity: +38%.

(60) 7: Release Properties of a Polymer Within the Aqueous Dispersion of the Invention:

(61) Composition of the Mixture: Formulation 3 82% by weight SBR DL 950 latex from Styron (Glass-transition temperature: 2 C.) 9% by weight polysiloxane: Xiameter MEM 0075 9% by weight Catalyst Syl-Off 7924

(62) This formulation was coated onto crepe paper and given that its measured peel strength was 1.78 N/5 cm exhibits release properties, whereas a substrate coated with only SBR latex has a high release strength at around 11.65 N/5 cm, which does not correspond to release values of commercial masking tape. Formulation 3, meanwhile, could be formulated in order to achieve targeted values of between 5 and 8 N/5 cm.

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

(63) Release Test:

(64) A sheet of 62 g/m.sup.2 flat back paper (AHLSTROM Mastertape Delicate 40062 g/m.sup.2) was coated with aqueous compositions using size press treatment. The dry deposition of this composition was between 6 and 7 g/m.sup.2:

(65) Formulation 4:

(66) Polymer=PVA.sup.1 (Moviol 4/98) modified with 3% by weight of undecenal.

(67) Polyhydrogenomethylsiloxane=Wacker Crosslinker V688, 7.5% by dry weight (relative to the dry weight of PVA).

(68) Catalyst=Wacker Catalyst Emulsion JB7, 5.5% by dry weight (relative to the dry weight of PVA).

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

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

(71) Sample 4: A piece of a commercial masking tape (COTEKA from Bricomarch, 5 cm width) was applied using a 10 kg roller on the side of a piece of flat back paper coated with the composition of the invention, formulation 3.

(72) TABLE-US-00009 Standard separation strength Separation strength (N/5 cm) Sample 1 2 3 Avg Sample 1 (COTEKA) 7.4 7.28 7.04 7.24 Sample 4 4.96 5.21 5.17 5.11

(73) It was noted that the peel strengths of the invention were on par with those of the commercial product, between 5 and 8 N/5 cm.