MXPA98000681A - Adhesive tape sensitive to pressure that does not return amari - Google Patents

Abstract

The present invention relates to a pressure sensitive adhesive tape which does not turn yellow, characterized in that it comprises a layer of polypropylene film with an antioxidant package of: i) 0.004 to 0.04% by weight of IRGANOX ™ 1010, ii) 0.03 to 0.2% by weight of a solid phosphite antioxidant, iii) 0.0 to 0.4% by weight of a thioester, and iv) 0.05 to 0.4% by weight of an acid cleaner inorganic. a pressure sensitive synthetic viscose rubber adhesive layer comprising 100 parts of a polystyrene-polydiene block copolymer, and 20 to 300 parts of a compatible viscosifying agent and an antioxidant package, based on 100 parts of the polystyrene block copolymer -polydiene, comprising: v) 0.1 to 0.6 parts of IRGANOX ™ 1010; vi) 0.1 to 0.6 parts of IRGANOX ™ 565; vii) 0.0 to 0.6 parts of a phosphate antioxidant;

Description

ADHESIVE TAPE SENSITIVE TO PRESSURE THAT DOES NOT RETURN YELLOW FIELD OF THE INVENTION The present invention relates to tapes that do not turn yellow formed with a pressure sensitive synthetic resin adhesive and a polyolefin film reinforcement. It has been found that pressure-sensitive adhesive tape articles, particularly extrusion-coated fibrous tapes in which a film layer is extruded onto a fibrous tissue material to form the tape reinforcement with the subsequently coated film layer. With a pressure sensitive adhesive, they are particularly sensitive to oxidation and turning yellow. Generally, this yellowing has little effect on the functionality performed but is nevertheless highly undesirable from an aesthetic perspective and consumer perspective. This is a particularly noticeable problem in polypropylene resin film layers and adhesive compositions sensitive to REF: 26666 pressure of synthetic block copolymers. There is a need to develop antioxidant formulations oriented towards the tendency of these products to become yellow with time.

BACKGROUND OF THE INVENTION A pressure-sensitive adhesive tape which does not turn yellow is provided, comprising a layer of polypropylene film with an antioxidant package in the film layer of: i) 0.004 to 0.04% by weight of IRGANOX ™ 1010, preferably 0.005% to 0.02% by weight; ii) 0.03 to 0.2% by weight of a solid phosphite antioxidant, preferably 0.04% to 0.12% by weight. iii) 0.05 to 0.4% by weight of a thioester, preferably 0.01 to 0.2% by weight; and iv) 0.05 to 0.4% by weight of an inorganic acid cleaner.

A viscous pressure sensitive synthetic rubber adhesive layer comprising 100 parts of a polystyrene-polydiene block copolymer, and 20 to 300 parts of a compatible viscosifying agent and an antioxidant package, based on 100 parts of the polystyrene block copolymer -polydiene, comprising: i) 0.1 to 0.6 parts of IRGANOX ™ 1010; ii) 0.1 to 0.6 parts of IRGANOX ™ 565; iii) 0.0 to 0.6 parts of a phosphite antioxidant; iv) preferably, the antioxidant package of the adhesive layer comprising: v) i) 0.1 to 0.3 part of IRGANOX ™ 1010; vi) 0.1 to 0.3 parts of IRGANOX ™ 565; vii) 0.0 to 0.4 parts of a phosphite antioxidant.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The pressure-sensitive adhesive tape of the invention comprising at least two non-adhesive layers forming the tape reinforcement, namely a layer of thermoplastic polymer film and a layer of fibrous tissue. The preferred thermoplastic polymer film layer is a polyolefin film or co-extruded film, with a polypropylene film or film layer being particularly preferred. A first side of the polypropylene film layer is coated with a pressure sensitive adhesive and generally the opposite side of the film layer is provided with a layer of fibrous tissue. The fibrous tissue layer may be a thermoplastic fibrous fabric such as a non-woven or woven fabric, a knitted fabric, or a woven weft or the like. The fibers forming the fibrous tissue are generally thermoplastic materials such as polyolefins or polyesters, polyesters being generally preferred. The fibrous web is then laminated or extruded with the thermoplastic polymer film layer, preferably a polypropylene film. The film prevents the pressure sensitive adhesive from blocking the tape as it flows through the fibrous structure not woven open. Generally, the polypropylene film layer is a homopolymer, polypropylene copolymer or a mixture such as ethylene, or polyethylene or other alkyl monomers and alpha-olefin polymers. The pressure sensitive adhesive is a viscous elastomer where the elastomer is a block copolymer of type A-B, in which blocks A and blocks B have linear, radial or star configurations. Block A is a mono-alkenyl arene, preferably a polystyrene with a molecular weight between 4000 and 50000 preferably between 7000 and 30,000. The content of block A is preferably about 10 to 50%, preferably about 10 to 30. % of the block copolymer. Other suitable A blocks can be formed from alpha-methyl styrene, t-butyl styrene and other styrenes alkylated in the ring, as well as mixtures thereof. Block B is a conjugated elastomeric diene, generally a polyisoprene with an average molecular weight of from about 5000 to about 500,000, preferably from about 50000 to about 200000. The viscosifying components of the elastomer-based adhesives. which generally comprises a solid viscosifying resin and / or a plasticizer or liquid viscosifier. Preferably, the viscosifying resins are selected from the group of resins that are at least partially compatible with the portion of the B block of polyisoprene or diene of the elastomer. While not preferred, generally a relatively minor amount of the resin may comprise resins compatible with the A block, which when present are generally so-called terminal block reinforcement resins. Generally, terminal block resins are formed from aromatic monomer species. Liquid plasticizers or viscosifiers suitable for use in the fixing tape adhesive composition including naphthenic oils, paraffin oils, aromatic oils, mineral oils or low molecular weight rosin esters, polyterpenes and C-5 resins. The viscosifying portion of the pressure sensitive adhesive generally comprising from 20 to 300 parts per 100 parts of the elastomeric phase. Preferably, it is a predominantly solid viscosifier, however, from 0 to 25% by weight, preferably from 0 to 10% by weight of the adhesive, which can be a liquid plasticizer or viscosifier.

EXAMPLES EXAMPLE 1 A roll of woven textured woven polyester fibrous loop fabric (MILLILOCK ™ style No. 924107-640 marketed by Milliken Co.) was extrusion coated on the opposite side to that of vertical fiber loops with a layer of polypropylene resin film of approximately 2.0 mil (50 microns). The polypropylene resin used is a TENITE ™ type resin P9-015 with an antioxidant combination of IRGANOX ™ 1010, IRGAFOS ™ 168, a thioester and hydrotalcite (experimental resin # X22807-37-3 from Eastman Chemical Co., now marketed by Huntsman Chemical as # P9-026). Next, a release layer (a 5% solution of polyvinyl N-octadecyl carbamate prepared as described in U.S. Patent No. 2,532,011) was coated on the fibrous loop side of the polypropylene-coated loop material. The excess solvent was dried in a forced air oven at approximately 170 ° F (77 ° C) to provide a dry release layer in the loops. A pressure sensitive adhesive was then hot-melt coated onto the polypropylene film layer. The adhesive composition used comprises 77 parts of a styrene-isoprene-type block copolymer resin KRATON ™ 1111, 23 parts of a SHELLFLEX ™ 371 OIL liquid viscosifying resin, 92 parts of WINGTACK ™ PLUS solid viscosifying resin, 1 part antioxidant ^ IRGANOX 1010, and a part of antioxidant IRGANOX ™ 565. The thickness of the adhesive coating is 50 microns. Samples of laminae of the fibrous material coated with adhesive (loop tape) were allowed to age for 12 days at room temperature 120 ° F (48 ° C), and 140 ° F (60 ° C) and then visually inspected for discoloration or yellowing. None of the samples had turned yellow. All the samples remained white. However, when aging naturally over a period of about three months, a trace of yellow was seen on the edge of the loop tape (in the form of a roll).

COMPARATIVE EXAMPLE 1 A roll of loop tape was prepared as described in Example 1, except that 2 parts of the IRGANOX ™ 1076 antioxidant was added to the adhesive in place of the IRGANOX ™ 1010 / IRGANOX ™ 565 combination. Loop tape samples were aged. as described in example 1 and then visually inspected for discoloration or yellowing. The samples aged at room temperature remained white; however, the heat-aged samples at 120 ° F (48 ° C) and 140 ° F (69 ° C) had turned yellow.

EXAMPLE 2 A roll of loop tape was prepared as described in example 1, except that the thermoplastic polymer resin used was the experimental resin # X22807-37-1 marketed by Eastman Chemical Co., now Hunstsman Chemical (zinc oxide was used in place of hydrotalcite). The loop ribbon samples were aged as described in Example 1 and then visually inspected for discoloration or yellowing. None of the samples had turned yellow. All the samples remained white.

However, by naturally aging over a period of about three months, the appearance of a trace of yellow on the edge of the loop tape was observed. (in the form of a roll).

COMPARATIVE EXAMPLE 2 A roll of loop tape was prepared as described in Example 2, except that 2 parts of the IRGANOX ™ 1076 antioxidant was added to the adhesive in place of the IRGANOX ™ 1010 / IRGANOX ™ 565 combination. Loop tape samples were aged. as described in example 1 and then visually inspected for any discoloration or yellowing. All samples showed yellowing.

COMPARATIVE EXAMPLE 3 A roll of loop tape was prepared as described in Example 1, except that TENITE ™ P9-015 polypropylene resin was used. Samples of the loop tape were aged as described in Example 1 and then visually inspected for any discoloration or yellowing. All the samples showed yellowing up to some points.

EXAMPLES 3-5 These examples were prepared to evaluate adhesives prepared with a different styrene-isoprene block copolymer elastomer. These examples examine the effect of different combinations of antioxidants on the adhesive on the discoloration of the loop tape. The adhesive compositions indicated in the following table I were coated by thermofusion on a fibrous loop material reinforced with polypropylene prepared as described in example 1.

TABLE 1 Example 1 Elastomer Viscous resin Antioxidant (parts) solid (parts) (parts 1) 3 100 WI GTACK ™ 95 IRGANOX ™ 565 80: (0, 1) IRGANOX ™ 1010 (0, 1) 100 95 IRGANOX ™ 565 or,?; POLYGARD ™ HR: or, 3: 100 WINGTACK1M 95 IRGANOX ™ 565 (80) (0.1) POLYGARD ™ HR (0.3) NAUGARD ™ 445 (0.3) 1 Parts per 100 parts of elastomer. The thickness of the adhesive coating of all the loop tape samples is 38 microns. The sheet samples of the loop tapes were aged at room temperature and also thermo-aged for 15 days at 140 ° F (60 ° C). Then, the yellowing of the samples was evaluated by measuring the LAB values (for example, the TAPPI test procedure # T-524). LAB values were measured using a LABSCAN Spectrum-colorimeter (Hunter Associates Laboratory, Inc., Reston, VA). The aging data at room temperature are summarized in Table II and the thermo-aging data are summarized in Table III. The LAB values were measured in the center of the sheet and also along one edge thereof.

TABLE II Example Average L Average A Average B (edge, center) (edge, center) (edge, center) 3 94.0.1; 94.05 • 1.23; -1.29 2.21; 2.31 4 93.94; 93.97 -1.28; -1.24 2.15; 2.03 5 93.99; 94.06 -1.31; -1.33 2.20; 2.27 TABLE III Example Average Average A Average B (edge; center) (edge; center) (edge; center) 3 93.65; 93.685 -1.3E • 1.39 2.82; 2.81 4 93.68; 93.43 -1.21; -1.3E 2.34; 3.23 5 93.69; 93.82 -1.32; -1.31 2.55; 2.57 The value L is a measure of white. The higher the L value, the more white the sample. The value A is a measure of green to red, the negative number indicates green and the positive red. The value B is a measure of blue to yellow, the negative number being an indication of blue and the positive being an indication of yellow. The more positive the B value, the more yellow the sample is. The samples are essentially white with very little yellow component.

COMPARATIVE EXAMPLES 4 AND EXAMPLES 6-8 These examples were prepared to examine the effect of varying the amount of antioxidant added to hot melt pressure sensitive adhesive formulations. Each of the adhesives indicated in the following Table IV was coated by hot melt over a polypropylene reinforced loop material prepared as described in Example 1, except that the polypropylene resin used is a TENITE ™ P9-015 polypropylene resin. The thickness of the adhesive coating is 50 microns.

TABLE IV Example Elastorner Viscosifying resin Visifying resin Antioxidant (parts) solid (partas) liquid (parts) (parts1) C4 KRATON- "WINGTAT" PLUS SHELLFLEX ™ 371 IRGANOX ™ 1111 (77) (92) (23) 1010 (1) IRGANOX "565 (1) KRATON WINGTAK 'PLUS SHELLFLEX ™ 371 IRGANOX'" 1111 (77) (92) (23) 1010 (0.5) IRGANOX ™ 565 (0.5) 7 KRATON ™ WINGTAK ™ PLUS SHELLFLEX ™ 371 IRGANOX ™ 1111 (77) (92) (23) 1010 (0.25) IRGANOX ™ 565 (0.25) 8 KRATON ™ WINGTAK ™ PLUS SHELLFLEX ™ 371 IRGANOX ™ 1111 (77) (92) (23) 1010 (0.125) IRGANOX ™ 565 (0.125) i parts per 100 parts of elastomer The samples of loop tapes were examined for color variation immediately after and about three months of natural aging. A decrease in the amount of yellowing was observed in the amounts of antioxidants from highest to lowest.

EXAMPLE 9 A roll of textured polyester fibrous loop fabric, woven by inserted warp (MILLILOCK ™ Style No. 924107-640 marketed by Milliken Co.) was coated by extrusion on the opposite side to that of vertical fiber loops with a layer of polypropylene resin film of 2.00 mil ( 50 microns) approximately. The polypropylene resin used is # SRC-7-558 from Shell Chemical Co. The resin has an antioxidant combination of IRGANOX ™ 1010, IRGANOX ™ 626, and hydrotalcite. Next, a release layer was placed on the fibrous loop side of the fibrous loop material reinforced with polypropylene. The release agent used is an organopolysiloxane-polyurea block copolymer prepared by the condensation reaction of an organopolysiloxane diamine with a diisoxyanate and a diamine chain filler as described in US Patent Nos. 5,214,119 and 5,290,615. The release agent was coated with a 5% solution in isopropyl alcohol and then baked. A pressure sensitive adhesive was coated on the polypropylene film layer by heat fusion. The adhesive composition used was 100 parts of a styrene-isoprene block copolymer resin, 100 parts of INGTACK ™ PLUS solid viscosifying resin, 0.12 parts of IRGANOX ™ 1010 antioxidant and 0.12 parts of IRGANOX ™ 565 antioxidant. The thickness of the adhesive coating is 38 microns. The yellowing of the loop tape was then evaluated by measuring the LAB values as described in Examples 3-5. The LAB values are L = 94.03, A = -1.08 and B = 2.02. TENITE ™ P9-015 is a polypropylene resin with an MFI of 75, marketed by Eastman Chemical Co. KRATON ™ 1111 is a polystyrene-polyisoprene linear block copolymer sold by Shell Chemical Co. With a S-I diblock of about %, triblock S-I-S- of 85%, and a styrene content of approximately 21%. KRATON ™ 1119 is a polystyrene-polyisoprene linear block copolymer sold by Shell Chemical Co. With a S-I diblock of about 65%, triblock S-I-S- of 35%, and a styrene content of approximately 22%. WINGTAK ™ PLUS is a C5 solid viscosifying resin with. a Tg of 315K and is available from Goodyear Chemical Co. WINGTAK ™ 95 is a solid viscosifying resin Cs with a Tg of 323K and is available from Goodyear Chemical Co.

SHELLFLEX ™ - 371 is a naphthenic oil with a Tg of 209K marketed by Shell chemical Co. IRGANOX ™ 1076 is a hindered phenol antioxidant (CAS name: benzenepropanoic acid, 3,5-bis (1,1-dimethylethyl) -4- hydroxy-, octadecyl ester) of Ciba-Geigy. IRGANOX ™ 1010 is a hindered phenol antioxidant (CAS name: benzenepropanoic acid, 3,5-bis (1,1-dimethylethyl) -4-hydroxy-, 2,2-bis [[3- [3,5-bis ( 1,1-dimethylethyl) -4-hydroxy-, 2,2-bis [[3- [3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] -l-oxo-propoxy] methyl] -1,3 -propanediyl ester) from Ciba-Geigy. IRGANOX ™ 565 is a hindered phenol antioxidant (CAS designation: phenol, 4- [[4,6-bis (octylthio) -1,3,5-triazin-2-yl] amino] -2,6-bis (1 , 1-dimethylethyl) -) from Ciba-Geigy. IRGAFOS ™ 168 is a phosphite antioxidant (CAS designation [phenol, 2,4-bis (l, l-dimethylethyl) -, phosphite. {3: 1.}., From Ciba-Geigy, POLYGARD ™ HR is an antioxidant phosphite (tris (nonylphenyl) phosphite) from Uniroyal NAUGARD ™ 445 is a phosphite (tris (nonylphenyl) phosphite) antioxidant from Uniroyal.

ULTRANOX ™ - 626 is a phosphite antioxidant (bis (2,4-di-t-butyl) pentaerythritol diphosphite) from Borg-Warner.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates. Having described the invention as above, the content of the following is claimed as property.

Claims (8)

1. - A pressure-sensitive adhesive tape that does not turn yellow, characterized in that it comprises a layer of polypropylene film with an antioxidant package of: i) 0.004 to 0.04% by weight of IRGANOX ™ 1010, ii) 0.03 to 0.2% by weight of a solid phosphite antioxidant, • •, iii) 0.0 to 0.4% by weight of a thioester, and iv) 0.05 to 0.4% by weight of an inorganic acid cleaner; has a viscous pressure-sensitive synthetic rubber adhesive layer comprising 100 parts of a polystyrene-polydiene block copolymer, and 20 to 300 parts of a compatible viscosifying agent and an antioxidant package, based on 100 parts of the block copolymer of polystyrene-polydiene, comprising: v) 0.1 to 0.6 part of IRGANOX ™ 1010; vi) 0.1 to 0.6 parts of IRGANOX ™ 565; vii) 0.0 to 0.6 parts of a phosphite antioxidant;

2. - A tape that does not turn yellow according to claim 1, characterized in that it also comprises a layer of fibrous tissue.

3. - The tape that does not turn yellow according to claim 2, characterized in that the polypropylene film layer is a polypropylene copolymer of ethylene and propylene.

4. - The tape that does not turn yellow according to claim 2, characterized in that the polypropylene film layer is a mixture of a homopolymer or copolymer of polypropylene and homopolymer or polyethylene copolymer.

5. - The tape that does not turn yellow according to claim 2, characterized in that the fibrous fabric layer is a fibrous polyester fabric having a first and a second face, the first face is laminated on said layer of polypropylene film .

6. - The non-yellowing tape according to claim 5, characterized in that the adhesive layer comprising, based on 100 parts of a polystyrene-polydiene block copolymer, an antioxidant package comprising: i) 0.1 to 0.3 parts of IRGANOX ™ 1010; ii) 0.1 to 0.3 parts of IRGANOX ™ 565; iii) 0.0 to 0.4 part of a phosphate antioxidant.

7. - The tape that does not turn yellow according to claim 6, characterized in that the acid cleaner comprises hydrotalcite.

8. - The tape that does not turn yellow according to claim 6, characterized in that the acid cleaner comprises zinc oxide. SUMMARY OF THE INVENTION The pressure-sensitive adhesive tape that does not turn yellow, with a layer of polyolefin film and a layer of fibrous tissue. A layer of propylene film having an antioxidant package of: i) 0.004 to 0.04% by weight of IRGANOX ™ 1010, ii) 0.03 to 0.2% by weight of a solid phosphite antioxidant, iii) 0.05 to 0.4% by weight of a thioester, and iv) 0.05 to 0.4% by weight of an inorganic acid cleaner. The viscous pressure adhesive layer of synthetic rubber comprising 100 parts of a polystyrene-polydiene block copolymer, and 20 to 300 parts of a compatible viscosifying agent and an anti-oxidizing packet, based on 100 parts of the block copolymer of polystyrene-polydiene, comprising: i) 0.1 to 0.6 parts of IRGANOX ™ 1010; ii) 0.1 to 0.6 parts of IRGANOX ™ 565; iii) 0.0 to 0.6 parts of a phosphite antioxidant;