WO2001070896A2

WO2001070896A2 - Monoaxially oriented polypropylene reinforced tape

Info

Publication number: WO2001070896A2
Application number: PCT/US2001/006702
Authority: WO
Inventors: Edward W. Richardson; Timothy V. Stagg
Original assignee: 3M Innovative Properties Company
Priority date: 2000-03-17
Filing date: 2001-03-01
Publication date: 2001-09-27
Also published as: WO2001070896A3

Abstract

Disclosed is a tape that includes a monoaxially oriented polypropylene film, and yarn adhered to the film.

Description

MONOAXIALLY ORIENTED POLYPROPYLENE REINFORCED TAPE

Technical Field The invention relates to monoaxially oriented polypropylene (MOPP) reinforced tape.

Background of the Invention Reinforced tape often includes a number of strands of fiberglass yarn adhered to a biaxially oriented polypropylene (BOPP) film backing. Other available reinforced tapes include fiberglass or polymeric yarn adhered to a polyester backing, and polypropylene filaments adhered to a monoaxially oriented polypropylene backing. Usually a pressure sensitive adhesive composition is then applied over the yarn or filaments.

High modulus reinforcements, e.g., fiberglass yarn, are commonly used in tape to impart strength to the tape. Compared to organic filaments such as polyester filaments, glass yarn exhibits virtually no elongation and is much more brittle in nature. Under high speed/impact conditions, e.g., the conditions experienced by appliances during shipping, the break energy of the tape is lowered dramatically for the more brittle fiberglass tape due to the nature of the glass yarn.

Summary In one aspect, the invention features a tape that includes a monoaxially oriented polypropylene film and yarn adhered to the film. In one embodiment, the tape further includes an adhesive composition disposed on a major surface of the tape. In some embodiments, the tape further includes an exposed adhesive composition in contact with the yarn. In another embodiment, the tape is free of paper.

In other embodiments, the yarn includes at least one of fiberglass and polymeric filaments. In some embodiments, the yarn includes polyester.

In another aspect, the invention features a tape that includes a monoaxially oriented polypropylene film and yarn adhered to the film where the tape exhibits a break energy of at least about 169 N-cm, and the force required to elongate the tape 5 % is at least about 50 N/cm. In one embodiment, the yarn includes at least one of fiberglass and polymeric filaments. In some embodiments, the yarn includes polyester. In other embodiments, the tape further includes an adhesive composition disposed on a major surface of the tape. In one embodiment, the tape exhibits a tensile strength at break of at least about 200 N/cm.

In another embodiment, the yarn is arranged in a parallel relationship along the machine direction of the tape. In some embodiments, the force required to elongate the tape 5 % is at least about 123 N/cm. In other embodiments, the tape exhibits a break energy of at least about 282 N-cm.

In other aspects, the invention features a method of manufacturing a tape that includes adhering yarn to a monoaxially oriented polypropylene film. In one embodiment, the tape exhibits a break energy of at least about 169 N-cm, and the force required to elongate the tape 5 % is at least about 50 N/cm. In other embodiment the method further includes coating an adhesive composition on a major surface of the tape.

The inventors have discovered that a monoaxially oriented polypropylene film that is reinforced with fiberglass yarn exhibits properties that are well suited to applications that include high speed/impact conditions including, e.g., holding appliances together (e.g., maintaining doors and drawers in a closed position) during shipping and bundling components (e.g., pipes) together. The tape also exhibits higher break energy relative to similarly constructed tape having biaxially oriented polypropylene or polyester film backings. The polymeric yarn reinforced monoaxially oriented polypropylene tape exhibits good tensile strength and tear resistance. The yarn reinforced monoaxially oriented polypropylene tapes can also be manufactured to exhibit a desirable break energy with fewer yarns per unit area relative to a biaxially oriented polypropylene tape.

A "filament" refers to a single fiber. A "yarn" refers to a plurality of filaments twisted around each other.

Other features of the invention will be apparent from the following description of preferred embodiments thereof, and from the claims. Detailed Description The tape includes a monoaxially oriented polypropylene film and yarn adhered to the film.

The tape preferably exhibits a break energy of at least about 169 N-cm (15 in-lb), more preferably at least about 282 N-cm (25 in-lb), most preferably at least about 339 N- cm (30 in-lb), a 5 % elongation force of at least about 50 N/cm (29 lb/in), more preferably at least about 123 N/cm (70 lb/in), most preferably at least about 175 N/cm (100 lb/in), a tensile strength at break of at least about 140 N/cm (80 lb/in), more preferably at least about 175 N/cm (100 lb/in), most preferably at least about 210 N/cm (120 lb/in), and an elongation at break of at least about 12 %.

Tape that includes polymeric yarn preferably exhibits a tensile at break of at least about 200 N/cm (114 lb/in), more preferably at least about 220 N/cm (126 lb/in), most preferably at least about 240 N/cm (137 lb/in).

Monoaxially oriented polypropylene film is available in a variety of dimensions and can be selected to achieve desired tape properties. The thickness (i.e., minor surface) of the film can be increased to increase properties of the tape such as the break energy, tensile at break and 5 % elongation force.

The yarn can include fiberglass or polymeric filaments and combinations thereof. Fiberglass yarn is available in a variety of deniers and can be selected to achieve a tape having the desired properties. Useful fiberglass yarn has a denier of from about 200 to about 600. Fiberglass yarn is commercially available under the designation ECG150 298 denier fiberglass yarn, and ECG75 595 denier fiberglass yarn from PPG Industries (Lexington, North Carolina), and from Advanced Glass Yarn (AGY) (Aiken, South Carolina). Fiberglass is also available in the form of webs that include interwoven strands of fiberglass yarn and entangled fiberglass yarn.

Preferably the polymeric yarn is polyester. Other useful polymers include polypropylene, polyethylene, polyvinyl chloride, polyvinyl acetate, nylon, and combinations thereof.

The amount of yarn (e.g., the number of strands of yarn) per unit area adhered to the backing is selected to provide a tape with desired properties. As the amount of yarn per unit area is increased, the tensile strength of the tape increases. When the yarn is arranged in a side-by-side relationship in the machine direction of the backing, the tape preferably includes from about 6 to about 40 ends (i.e., strands of yarn) per cm width, more preferably from about 8 to about 16 ends per cm width.

The tape can optionally include an adhesive composition coated on a major surface of the tape. Preferably the adhesive composition is coated on the yarn side of the tape. A variety of adhesive compositions are suitable. The adhesive composition can be a hotmelt, transfer-coatable, solvent-coatable, water-based, or latex formulation.

Examples of useful adhesives include those based on general compositions of polyacrylate; polyvinyl ether; diene-containing rubber such as natural rubber, polyisoprene, and polyisobutylene; polychloroprene; butyl rubber; butadiene-acrylonitrile polymer; thermoplastic elastomer; block copolymers such as styrene-isoprene and styrene- isoprene-styrene block copolymers, ethylene-propylenediene polymers, and styrene- butadiene polymer; poly-alpha-olefin; amorphous polyolefin; silicone; ethylene-containing copolymer such as ethylene vinyl acetate, ethylacrylate, and ethyl methacrylate; polyurethane; polyamide; epoxy; polyvinylpyrrolidone and vinylpyrrolidone copolymers; polyesters; and mixtures of the above.

Additionally, the adhesives can contain additives such as tackifiers, plasticizers, fillers, antioxidants, stabilizers, pigments, diffusing particles, curatives, and solvents.

Preferably the adhesive composition is a pressure sensitive adhesive composition. Pressure sensitive adhesives are normally tacky at room temperature and can be adhered to a surface by application of, at most, light finger pressure. Suitable pressure sensitive adhesives include solvent, hot melt and UN cured adhesives. A general description of useful pressure sensitive adhesives may be found in Encyclopedia of Polymer Science and Engineering, Vol. 13, Wiley-Interscience Publishers (New York, 1988). Additional description of useful pressure sensitive adhesives may be found in Encyclopedia of Polymer Science and Technology, Vol. 1, Interscience Publishers (New York, 1964). The adhesive coating can be continuous or discontinuous. The tape can also include a release coating (a low adhesion backsize (LAB) coating) on the major surface of the backing opposite the adhesive composition to allow the tape to unwind from itself when wound in a roll. The release coating is selected to be compatible with the adhesive composition.

Release coating compositions may include silicone, alkyl, or fluorochemical constituents, or combinations as the release-imparting component. Useful release coating compositions include silicone-containing polymers, such as silicone polyurethanes, silicone polyureas and silicone polyurethane/ureas, such as those described in U.S. Patent Nos. 5,214,119, 5,290,615, 5,750,630, and 5,356,706, and silicone acrylate grafted copolymers described in U.S. Patent Nos. 5,032,460, 5,202,190, and 4,728,571. Other useful release coating compositions include fluorochemical-containing polymers such as those described in U.S. Patent No. 3,318,852, and polymers containing long alkyl side chains such as polyvinyl N-alkyl carbamates (e.g., polyvinyl N-octadecyl carbamates) as described in U.S. Patent No. 2,532,011, and copolymers containing higher alkyl acrylates (e.g., octadecyl acrylate or behenyl acrylate), such as those described in U.S. Patent No. 2,607,711, or alkyl methacrylates (e.g., stearyl methacrylate) such as those described in U.S. Patent Nos. 3,502,497 and 4,241,198, where the alkyl side chain includes from about 16 to 22 carbon atoms.

These release polymers can be blended with each other and with thermosetting resins or thermoplastic film forming polymers to form the release coating composition. The release coating composition can also include other additives such as fillers, pigments, wetting agents, viscosity modifiers, stabilizers, anti-oxidants, and cross-linking agents.

The tape can be prepared using a variety of methods. One suitable method includes coating a release composition on a major surface of a monoaxially oriented polypropylene backing, and a laminating adhesive composition (e.g., a pressure sensitive adhesive) on the opposite major surface of the monoaxially oriented polypropylene backing. Yarn is then adhered to the laminating adhesive. Strands of yarn are preferably arranged in a side-by-side relationship and aligned in the machine direction of the tape.

The yarn may also be provided in the form of a woven web. In one embodiment, the woven web is arranged in two arrays superimposed upon each other or intertwined with each other, where one array includes parallel strands of yarn oriented longitudinally along the length or machine direction of the tape backing while the other array includes parallel strands of yarn arranged at an angle to the longitudinal array. An adhesive composition is then applied to the yarn side of the composite structure. Preferably the adhesive composition penetrates the yarn and adheres to the laminating adhesive. The adhesive composition can also function as an adhesive surface. Optionally, an additional adhesive composition (i.e., the functional adhesive) can be coated on the adhesive layer that penetrates the yarns. Preferably the functional adhesive composition forms a bond with the adhesive layer that penetrates the yarns and the laminating adhesive.

The invention will now be described further by way of the following examples. All parts, ratios, percents and amounts stated in the Examples are by weight unless otherwise specified.

EXAMPLES Test Procedures

Test procedures used in the examples include the following.

Tensile Strength at Break. % Elongation at Break. Break Energy and Force at 5 % Elongation Test Methods

The test methods used to determine tensile strength at break, % elongation at break, break energy and the force required to elongate the tape 5 %, are ASTM D3759/D3759M-96E1, entitled, "Tensile Strength and Elongation of Pressure- Sensitive Tapes," with the exception that the jaw spacing is 10.2 cm (4 in) and the jaw speed is 10 m/min (400 in/min).

Sample Preparation EXAMPLE 1

A fiberglass yarn reinforced tape was prepared by coating a 82.5 μm (0.0033 in) x 159 cm (62.5 in) Blue 440/26/09 Tensilized T2S monoaxially oriented polypropylene (MOPP) film, (Nowofol, Siegsdorf, Germany) with a rubberized pressure sensitive adhesive composition. ECG 150 fiberglass yarn (PPG Industries, Lexington, NC) was applied to the adhesive composition such that the tape included 13 ends per cm (32 ends per inch) of fiberglass yarn arranged in a side-by-side (i.e., parallel) relationship in the machine direction of the tape. The adhesive coated backing and the strands of fiberglass yarn were then passed through a nip roller to adhere the fiberglass yarn to the MOPP film. A rubberized based adhesive composition was then applied to the fiberglass yarn surface of the tape. EXAMPLE 2

A polyester yarn reinforced tape was prepared by coating a 50 μm (0.0020 in) x 127 cm (50 in) Blue 440/26/09 Tensilized T2S monoaxially oriented polypropylene (MOPP) film, (Nowofol, Siegsdorf, Germany) with a rubberized pressure sensitive adhesive composition. 500 denier 500/70/1W70 merge 11348 polyester yarn (Honeywell (Allied-Signal) Inc., Moncure, North Carolina) was applied to the adhesive composition such that the tape included 9 ends per cm (22 ends per inch) polyester yarn arranged in a side-by-side (i.e., parallel) relationship in the machine direction of the tape. The adhesive coated backing and the strands of polyester yarn were then passed through a nip roller to adhere the polyester yarn to the MOPP film.

A rubberized based adhesive composition was then applied to the polyester yarn surface of the tape.

The reinforced tapes of Examples 1 and 2 were then tested to determine the force required to achieve 5 % elongation, break energy, tensile strength at break, and % elongation at break. The results are reported in Table 1.

Table 1

Other embodiments are within the claims.

Claims

1. A tape comprising: a monoaxially oriented polypropylene film; and yarn adhered to the film.

2. The tape of claim 1, further comprising an adhesive composition disposed on a major surface of the tape.

3. The tape of claim 1, further comprising an exposed adhesive composition in contact with the yarn.

4. The tape of claim 1, wherein the tape is free of paper.

5. The tape of claim 1, wherein the yarn comprises filaments comprising at least one of fiberglass and a polymer.

6. The tape of claim 1, wherein the yarn comprises polyester.

7. A tape comprising: a monoaxially oriented polypropylene film; and yarn adhered to the film the tape exhibiting a break energy of at least about 169 N-cm, and the force required to elongate the tape 5 % is at least about 50 N/cm.

8. The tape of claim 7, wherein the yarn comprises filaments comprising at least one of fiberglass and a polymer.

9. The tape of claim 7, wherein the yarn comprises polyester.

10. The tape of claim 9, further comprising an adhesive composition disposed on a major surface of the tape.

11. The tape of claim 9, wherein the tape exhibits a tensile strength at break of at least about 200 N/cm.

12. The tape of claim 7, further comprising an adhesive composition disposed on a major surface of the tape.

13. The tape of claim 7, wherein the yarn is arranged in a parallel relationship along the machine direction of the tape.

14. The tape of claim 7, wherein the force required to elongate the tape 5 % is at least about 123 N/cm.

15. The tape of claim 7, wherein the tape exhibits a break energy of at least about 282 N-cm.

16. A method of manufacturing a tape comprising adhering yarn to a monoaxially oriented polypropylene film.

17. The method of claim 16, wherein the tape exhibits a break energy of at least about 169 N-cm, and the force required to elongate the tape 5 % is at least about 50 N/cm.

18. The method of claim 16, further comprising coating an adhesive composition on a major surface of the tape.