Source: http://www.google.com/patents/US6866928?dq=6,108,703
Timestamp: 2017-08-21 21:43:49
Document Index: 524128690

Matched Legal Cases: ['§ 25', '§ 25', '§ 25', '§ 25', '§ 25', '§ 25', '§ 25', '§ 25', '§ 25', '§ 25', '§ 25', '§ 25']

Patent US6866928 - Cleanly removable tapes and methods for the manufacture thereof - Google Patents
The present invention provides a multi-layer tape, comprising: a first adhesive layer comprising a pressure sensitive adhesive; a core layer having an outer surface, the first adhesive layer adhered to at least a portion of the outer surface; and fibrous reinforcing material dispersed within the core...http://www.google.com/patents/US6866928?utm_source=gb-gplus-sharePatent US6866928 - Cleanly removable tapes and methods for the manufacture thereof
Publication number US6866928 B2
Application number US 10/118,120
Also published as CN1268706C, CN1646653A, DE60306507D1, DE60306507T2, EP1492852A1, EP1492852B1, US20030190464, US20050142359, WO2003087252A1
Publication number 10118120, 118120, US 6866928 B2, US 6866928B2, US-B2-6866928, US6866928 B2, US6866928B2
Inventors Timothy N. Narum, James J. Kobe, Rodger J. Pereyra, Zhiming Zhou
Patent Citations (37), Non-Patent Citations (2), Referenced by (60), Classifications (35), Legal Events (6)
US 6866928 B2
The present invention provides a multi-layer tape, comprising: a first adhesive layer comprising a pressure sensitive adhesive; a core layer having an outer surface, the first adhesive layer adhered to at least a portion of the outer surface; and fibrous reinforcing material dispersed within the core layer, the fibrous reinforcing material imparting stretch release properties to the tape. The tape may comprise a second adhesive layer wherein the outer surface comprises a first major surface and a second major surface, the first adhesive layer being adhered to the first major surface, and the second adhesive layer being adhered to the second major surface. A fire retardant may be disposed in any of the first adhesive layer, the second adhesive layer, and the core layer. The tape may be cleanly removable. The fibrous reinforcing material typically comprises substantially continuous viscoelastic microfibers having a yield strength and a tensile break strength, and the tensile break strength is at least about 150% of the yield strength. In another aspect, the tapes of the invention may be formulated to be cleanly removable without including fibrous reinforcing material therein. The invention also provides a method for the manufacture of the foregoing tape as well as an assembly comprising: a substrate; a carpet overlying the substrate; and a tape according to the invention disposed between the carpet and the substrate and adhering the carpet to the substrate.
a first adhesive layer comprising a first pressure sensitive adhesive;
a second adhesive layer comprising a second pressure sensitive adhesive;
a core layer disposed between said first adhesive layer and said second adhesive layer;
a fire retardant disposed in at least one of the first adhesive layer or the second adhesive layer, the fire retardant being essentially free of antimony fire retardants and polybrominated biphenyls;
reinforcing microfibers disposed in the core layer, the reinforcing microfibers oriented in the machine direction of the core layer and providing stretch release properties to the carpet tape; and
the tape capable of passing (1) F.A.R.§ 25.853 (July 1990), 12 Second Vertical Burn Test; and being cleanly removable.
2. The fire retardant, multi-layer carpet tape of claim 1 wherein the core layer comprises a fire retardant, the fire retardant being essentially free of antimony fire retardants and polybrominated biphenyls.
Providing a core layer having an outer surface;
Applying a first adhesive layer to at least a portion of the outer surface, the first adhesive layer comprising a first pressure sensitive adhesive;
At least one of the first adhesive layer or the core layer further comprise a fire retardant selected from the group consisting of antimony free fire retardant, polybrominated biphenyl free fire retardant, intumescent fire retardant, and combinations of the foregoing, wherein the tape will pass (1) F.A.R.§ 25.853 (July 1990), 12 Second Vertical Burn Test; and
The core layer further comprising reinforcing microfibers oriented in the machine direction of the core layer, the reinforcing microfibers providing stretch release properties to the tape.
10. The method of claim 9 wherein the outer surface comprises a first major surface and a second major surface, the applying of a first adhesive layer comprises applying the pressure sensitive adhesive to the first major surface, the method further comprising applying a second adhesive layer to the second major surface.
a carpet overlying the substrate; and
the tape of claim 1 disposed between the carpet and the substrate and adhering the carpet to the substrate.
Adhesive materials, including pressure sensitive adhesives (PSAs), are commercially available for use in any of a variety of applications and industries such as in the construction of mounting tapes, carpet tapes and the like. Some carpet tapes comprise a backing, such as, for example, a cloth or film backing, with an adhesive coating on each of the major surfaces of the backing. Adhesives used in carpet tape applications have typically been pressure sensitive adhesives having (1) aggressive and permanent tack, (2) adherence to both a substrate and an adherend (e.g., a carpet backing) with no more than finger pressure, and preferably (3) being removable from the adherend. Pressure-sensitive adhesive tapes, such as carpet tapes, provide a strong bond to substrates because separation of the tapes from the substrates is neither intended, nor desired. When removal of the carpet is desired, pressure sensitive carpet tapes made with aggressively tacky PSAs have been very difficult to remove from a substrate and may result in damage to the substrate or may leave a tacky adhesive residue. Substrate damage is especially problematic for aerospace carpet tape applications where the substrate, e.g., a floor panel, may be costly to replace. Moreover, during the life of a carpet, dirt is ground into the carpet fabric and, over time, penetrates through the carpet to damage the underlying tape by causing nicks, cuts or small tears in the tape backing. When the carpet is subsequently removed, the damage to the backing can cause the tape to break, making it more difficult to remove from the substrate.
Some pressure sensitive adhesives have been specifically formulated to allow clean and easy removal from substrates after use, such as, for example, the adhesive used for Post-It® brand removable notes, available from Minnesota Mining and Manufacturing Company of St. Paul, Minn. These adhesives, however, do not possess sufficient tack to provide a level of holding power sufficient for use in carpeting applications, for example. In general, adhesives that are formulated to provide a substantial level of adhesion, e.g., for holding a carpet to a substrate, are difficult to remove from a substrate without significant effort.
The pressure sensitive adhesives described in U.S. patent application Ser. No. 09/764,478 now abandoned comprise a fibrous reinforcing material. The patent application describes the fibrous reinforcement of pressure sensitive adhesives to provide “stretch removable” characteristics. The fiber reinforced adhesive composition comprises a pressure sensitive adhesive matrix with a fibrous reinforcing material therewithin. The fiber reinforced adhesive composition is described as providing improved cohesive strength over the pressure sensitive adhesive alone, while the tack of the pressure sensitive adhesive remains substantially unreduced by the presence of the fibers.
In applications for tapes and other articles, a fire retardant feature may be needed and, in certain applications, may be required by applicable regulations. For example, tapes for electric or electronic applications may be directly exposed to electrical current, to short circuits, and/or to heat generated from the use of the associated electronic component or electrical device. Consequently, industry standards or regulations may impose conditions on the use of such tape articles that require qualifying tests be performed on the tapes such as burn tests, and the like. For electrical and electronics applications, the industry standard flammability test is Underwriters Laboratories (UL 94 “Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances”). For rail transit applications, the industry standard is American Society for Testing and Materials ASTM E662 (“Test Method for Specific Optical Density of Smoke Generated by Solid Materials”) and ASTM E162 (“Test for Surface Flammability of Materials Using a Radiant Energy Source”).
For aerospace applications, the testing criteria for the Federal Aviation Administration F.A.R. § 25.853 (July 1990) vertical burn test, subparagraph (a)(1)(i), relates to interior compartments occupied by crews or passengers, including interior ceiling panels, interior wall panels, partitions, galley structures, large cabinet walls, structural flooring, and materials used in the construction of stowage compartments. F.A.R. § 25.853 (July 1990) subparagraph (a)(1)(ii) relates to carpet tapes, seat cushions, padding, decorative and non-decorative coated fabrics, leather, trays and galley furnishings, electrical conduit, thermal and acoustical insulation and insulation covering air ducting, joint and edge covering and the like. Materials used for these applications must be self-extinguishing when tested vertically in accordance with the procedures of F.A.R. § 25.853 (July 1990) (a)(1)(i) and (a)(1)(ii). In addition for both rail transit and aerospace applications, another industry standard is Boeing Specification Support Standard, BSS 7239 (“Test Method for Toxic Gas Generation by Materials of Combustion”) which requires analysis of combustion gases and has specified concentration limits on toxic gases which currently include HCN, NOx, CO, HCl, HF, and SO2.
Type II, Class 1—Maximum weight 16 oz/yd2, white color;
Type II, Class 2—Maximum weight 16 oz/yd2, black color;
Type III—Maximum weight 24 oz/yd2, white color;
Type IV, Class 1—Differential tack, maximum weight 5.0 oz/yd2, black color on side 2; and
Type IV, Class 2—Differential tack, maximum weight 9.0 oz/yd2, black color on side 2.
This specification lists key tests and requirements for each of the different Types. The specification includes weight, flammability according to F.A.R. § 25.853 (July 1990) (a)(1)(i) (12 Second Vertical Burn), tensile strength, peel strength, lap shear strength, corrosion to aluminum, and release liners.
1. Environment regulations requiring acceptable fire retardant systems; and
2. Clean removable tapes which effectively and efficiently improve the removal process and eliminate damage to floor substrates and which do not leave adhesive residue.
Cleanly removable tapes would provide a cost saving to the aerospace industry and would reduce or eliminate the need to use solvents to remove adhesive residues. Fire retardant carpet tapes will eventually be required to meet the new environmental legislation being adopted in Europe and around the world.
In one aspect, the invention provides a multi-layer tape, comprising: a first adhesive layer comprising a pressure sensitive adhesive; a core layer having an outer surface, the first adhesive layer adhered to at least a portion of the outer surface; and fibrous reinforcing material dispersed within the core layer, the fibrous reinforcing material imparting stretch release properties to the tape.
With a fire retardant included in the tape, the tape is formulated to pass (1) F.A.R. § 25.853 (July 1990), 12 Second Vertical Bum Test; (2) F.A.R. § 25.853 (July 1990), 60 Second Vertical Bum Test; (3) UL-94 V-2 rating; (4) ASTM E162 with maximum flame spread index of 35; (5) ASTM E662 with maximum specific optical density for flaming and nonflaming modes of 100 maximum (1.5 minutes) and 200 maximum (4.0 minutes); (6) BMS 5-133 C issued Sep. 29, 1993 except for tensile strength; or (7) BSS 7239. The tape may be cleanly removable. The fibrous reinforcing material typically comprises substantially continuous viscoelastic microfibers having a yield strength and a tensile break strength, and the tensile break strength is at least about 150% of the yield strength. The viscoelastic microfibers may be selected from homopolymers, copolymers, terpolymers, or tetrapolymers of polyalkylene resins and combinations of the foregoing. Other possible features are described herein.
“Substantially continuous,” when referring to fibers, means that for an at least 0.5 centimeter length sample of the adhesive composition taken in the machine direction, a substantial number of the fibers present in the sample are unbroken.
“Intumescent fire retardant” refers to an intumescent substance that when applied to or incorporated within a combustible material, reduces or eliminates the tendency of the material to ignite when exposed to heat or flame, induces charring and liberates non-combustible gases to form a carbonific material that protects the surrounding matrix, cuts off the oxygen supply, and prevents dripping. Intumescent fire retardants generally comprise an acid source, a char former, and a blowing agent.
“Fire retardant” refers to a substance that when applied to or incorporated within a combustible material, reduces or eliminates the tendency of the material to ignite when exposed to heat or flame.
“Stretch release” refers to the property of an adhesive article characterized in that, when the article is pulled from a surface or from between two surfaces at a rate of no greater than about 30 centimeters/minute and at an angle of no greater than about 45°, the article detaches from at least one of the surfaces of the substrates.
The invention provides a cleanly removable tape that can be used as a joining and mounting tape such as, for example, a carpet tape. The tapes are provided in layered constructions with stretch release properties to enable removal from a substrate without leaving significant residue on the surface of the substrate. The tapes comprise a core layer and at least a first adhesive layer adhered to at least a portion of the core layer. The tapes may be single sided tapes or double sided tapes. Single sided tapes are tapes having adhesive properties on one side only. Double sided tapes are tapes having adhesive properties on both sides.
The tape 10 may also include a tab (not shown) positioned thereon so that the tape 10 may be removed from a substrate by pulling the tab and the tape in the direction of the oriented microfibers 16, i.e., in the machine direction. In general, to remove a stretch releasable tape of the invention from between two substrates, the tape is moved by pulling on the tape or the tab in a direction substantially parallel to the two surfaces. For carpeting adhered to a floor, the carpet or other adhered material is first removed from the tape by pulling the carpet or other material from the second major surface 13 of the tape 10. The tape 10 will remain adhered to the floor along the first major surface 12 via first adhesive layer 18, and removal of the tape 10 from the floor is accomplished by then stretching the tape in the machine direction at an angle from about 20° to about 45°, relative to the surface of the floor. Alternatively, when the carpet or other material is pulled up from the surface of a floor, the layers of the tape 10 may separate from one another leaving portions of the tape 10 that can be removed from the material and the substrate by the stretch-release mechanism.
In the removal process, a force is applied to the tape in a direction substantially parallel to the surface of the floor or other substrate. The removal force may be applied by gripping the aforementioned removal tab or an end of the tape and pulling the tape in the aforementioned direction. When sufficient force is applied to overcome the initial yield strength, the backing or core layer will deform. When the tape comprises viscoelastic microfibers, the tape will initially deform and then yield as the microfibers elongate and orient, thereby undergoing strain hardening. In addition, orientation induced by stretching further detackifies the adhesive layer. Stretching will thin the tape significantly at the location where the adhesive pulls away from the substrate. Thinning of the tape dramatically reduces the force required to remove the tape from the substrate. Pulling the tape from the substrate at an angle of less than about 45° will aid in the removal of the tape from the laminate. In certain aerospace applications, the substrate can be a fiber reinforced composite laminate or panel, and pulling the tape from the substrate at the foregoing angle significantly reduces the possibility that the panel surface will delaminate as a result of the tape removal process. Following the removal of the tape, the surface will be substantially clean with little or no visible adhesive residue remaining thereon.
Blends of one or more fire retardants may also be used in the tapes of the invention. Suitable blends include blends of EXOLIT AP 750 and FR370 and EXOLIT IFR 23 and FR 370 in a weight ratio ranging from about 5:95 to about 95:5, and blends of mono-ammonium phosphate, ammonium sulfate, and magnesium aluminum silicate available as FORAY from Ansul Incorporated. Blends of one or more fire retardants and a synergist may also be used in the tapes of the invention. Suitable synergists include talc, magnesium compounds, zinc compounds such as zinc borate, Fe2O3, MoO3, special zeolite, boroxo siloxane elastomer, which are discussed in article “Influence of Modified Rheology on the Efficiency of Intumescent Flame Retardant Systems”, P. Anna et al., Polymer Degradation and Stability, Vol. 74 (3), 2001, pp. 423 to 426. A synergist for both brominated and phosphorus fire retardants is CIBA FLAMESTAB NOR 116 fire retardant material available from Ciba, Tarrytown, N.Y. There appears to be a synergy between the ammonium polyphosphate based intumescent fire retardants with brominated phosphate, melamine phosphate, and/or melamine polyphosphate fire retardants. While halogenated fire retardant materials are generally not preferred, some halogenated materials may be effective in the present invention.
Referring to FIG. 4, an extrusion process is shown for preparing stretch release tape according to the invention. According to the process of the invention, polymer resin or adhesive polymer is fed into a first extruder 310 (typically a single screw extruder) to soften, grind, or melt the resin into a form suitable for extrusion. The resulting polymer resin will form the core layer. The polymer resin may be added to the extruder 310 in any convenient form, such as pellets, billets, packages, strands, pouches and ropes. Next, the polymer resin is fed to a second extruder 312 (e.g., typically a twin screw extruder). The polymer resin may be fed directly from the extruder 310 into second extruder 312 through port 311. Other additives, such as fire retardants and microfiber forming resin, can be fed into any port and are typically fed into the second extruder 312 at entrance 313 and are well mixed in a kneading zone. The order of component addition and mixing conditions (e.g., screw speed, screw length, and temperature) are selected to achieve optimum mixing. Generally, mixing is carried out at a temperature of at least about 10° C. above the melting point temperature of the microfiber forming resin and less than about the degradation temperature of the material to which the microfiber forming resin is added and/or the microfiber forming resin. Generally, mixing is carried out at a temperature between about 140° C. to about 170° C. However, higher temperatures may be used. It will be appreciated that if the polymer resin is provided in a form suitable for extrusion, the first extrusion step may be omitted, and the resin is added directly to extruder 312.
The pressure within the die 314 will generally decreases as the polymer core composition approaches the exit port 315 of the die 314. The flow rate of the extrudable polymer composition through the extruder 312 and the die 314 is maintained to adequately process the core layer, as known by those skilled in the art. The manufacturing process temperatures are typically chosen so that the temperature of the highest or last zone is between at least about 10° C. above the melting point (low limit) of elastic, viscoelastic, or combination of elastic and viscoelastic polymer resins and less than about the degradation temperature of the components. Moreover, the temperature of the die 314 is generally no greater than about 60° C. over the melting point of the microfiber forming polymer so that the microfiber can effectively consolidate by crystallizing upon cooling into relatively long, substantially continuous microfibers.
The release liners are typically coated with release agents such as fluorochemicals or silicones. For example, U.S. Pat. No. 4,472,480 describes low surface energy perfluorochemical liners. Suitable release liners include papers, polyolefin films, or polyester films coated with silicone release materials. Examples of commercially available silicone coated release liners are POLYSLIK™ silicone release papers available from James River Co., H.P. Smith Division (Bedford Park, Ill.) and silicone release papers supplied by DCP-Lohja (Dixon, Ill.) now known as Loparex Inc. (Willowbrook, Ill.). A particular release liner is that known by the designation 1-60BKG-157, a super calendared Kraft paper with a water-based silicone release surface, available from Daubert Chemical Co. Other types of stable, contaminent free, release liners are also useful in the invention such as those described in U.S. patent application Ser. No. 09/775,955 incorporated herein by reference.
This test method is based on the criteria and procedures for showing compliance with F.A.R. § 25.853 (July 1990) but differs from F.A.R. § 25.853 (July 1990) in that the specimens (samples) were conditioned at 50%±10% relative humidity for a minimum of 24 hours instead of the specified 50%±5%.
Samples were conditioned to 21.1° C.±2.8° C. (70°±5°F.) and at 50%±10% relative humidity for a minimum of 24 hours. Specimens were mounted into a U-shaped metal frame so that the two long edges and one narrow edge were held securely in a vertical orientation, unsupported by and unattached to a substrate. The exposed area of the specimen was at least 50.8 mm (two inches) wide and about 304.8 mm (12 inches) long.
The samples were exposed to the flame from a Bunsen burner. The lower edge of the sample was about 19.1 mm (¾ inch) above the top edge of the burner. The flame was applied to the center line of the lower edge of the sample for 12 seconds. The flame time, burn length, and flaming time of dripping, if any, was recorded. Burn length was the distance from the original edge of the sample that was exposed to the flame to the point which is the farthest evidence of damage to the test specimen due to flame impingement including area of partial or complete consumption, charring, or embrittlement, but not including areas sooted, stained, warped, or discolored, nor areas where material had shrunk or melted away from the heat.
F.A.R. § 25.853 (July 1990) subparagraphs (a)(1)(i) 60 second flame exposure require that the average burn length not exceed 152.4 mm (six inches), the average flame time after removal of the flame source not exceed 15 seconds, and drips not continue to flame for more than an average of 3 seconds after falling. F.A.R. § 25.853 (July 1990) subparagraphs (a)(1)(ii) 12 second flame exposure require the average burn length not exceed 203 mm (8 inches), the average flame time after removal of the flame source not exceed 15 seconds, and drips not continue to flame for more than an average of 5 seconds after falling.
A 12.7 mm (one-half inch) wide by about 152 mm (6 inches) long sample was cut from the article to be tested and laminated to an about 165 mm (6.5 inches) long by about 28.6 mm (1.125 inches) wide by 0.051 mm (0.002 inches) thick aluminum foil by rolling down the article onto the aluminum foil, taking care not to trap air bubbles between the foil and the article. The foil/article laminate was then positioned on a clean, dry, 51 mm (two inches) wide by about 127 mm (5 inches) long, substrate panel of stainless steel or to a Boeing composite, as specified in the Examples below, so that the laminate was centered on the panel with a portion of the laminate extending off the panel to serve as a tab. The laminate was rolled down onto the panel using a 2 kg (4.5 lb) hard rubber roller, with two passes in each direction. Care was taken not to trap bubbles between the panel and the laminate. The sample thus prepared was allowed to dwell at room temperature (about 22° C.) or at 70° C. for about 72 hours. Then the sample was tested at room temperature (about 22° C.) for 90 Degree Peel Adhesion according to the Pressure Sensitive Tape Council test method PSTC-5 “Quick Stick of Pressure Sensitive Tapes” at crosshead speed of 30 cm/minute (12 inches/minute) using an INSTRON tensile tester. That is, the peel value obtained from the first 25.4 mm (one inch) length of peel was ignored. The peel value of the next 89 mm (3.5 inches) or “peel area” was recorded. The values reported were the integrated peel adhesion values. Failure mode was also noted for 70° C. aged samples.
A 12.7 mm (one half inch) wide by about 152 mm (6 inches) long sample was cut from the article to be tested and laminated to an about 165 mm (6.5 inches) long by about 28.6 mm (1.125 inches) wide by 0.051 mm (0.002 inches) thick aluminum foil by rolling down the article onto the aluminum foil, taking care not to trap air bubbles between the foil and the article. The foil/article laminate was then positioned on a clean, dry, 51 mm (two inches) wide by about 127 mm (5 inches) long, back of a carpet panel, FELTEX CARPET Style 282131, available from Feltex Carpet Ltd, Auckland, NZ, so that the laminate was centered on the carpet back with a portion of the laminate extending off the carpet back to serve as a tab. The laminate was rolled down onto the carpet back using a 2 kg (4.5 lb) hard rubber roller, with two passes in each direction. Care was taken not to trap bubbles between the carpet back and the laminate. The sample thus prepared was allowed to dwell at room temperature (about 22° C.) or at 70° C. for about 72 hours. Then the sample was tested at room temperature (about 22° C.) according to ASTM D-1876-01 “Peel Resistance of Adhesives (T-Peel Test)” at crosshead speed of 30 cm/minute (12 inches/minute) using an INSTRON tensile tester. The peel value obtained from the first 25.4 mm (one inch) length of peel was ignored. The peel value of the next 89 mm (3.5 inches) or “peel area” was recorded. The values reported were the integrated peel adhesion values.
A 1.27 cm (one-half inch) wide by about 15.2 cm (6 inches) long sample was cut from the article to be tested and laminated to a sheet of anodized aluminum foil (about 16.5 cm (6.5 inches) long by 2.86 cm (1.125 inches) wide by 0.0127 cm (0.005 inches) thick) by rolling down the article onto the anodized side of the aluminum foil, taking care not to trap air bubbles between the foil and the article. The foil/article laminate was then cut in half to give two about 2.54 cm×about 7.62 cm (1 inch×3 inches) test specimens. The liner was removed from a test specimen and then positioned on a clean, dry, 5.1 cm (two inches) wide by 12.7 cm (5 inches) long, stainless steel substrate panel so that the laminate was centered on one end of the panel so that 2.54 cm (1 inch) length was adhered (i.e. 3.13 sq. cm (0.5 sq. inch) bond area) and the 5.1 cm (2 inches) portion of the laminate extended off the panel to serve as a tab. The laminate was rolled down onto the panel using a 2 kg (4.5 lb) hard rubber roller, with two passes in each direction. Care was taken not to trap bubbles between the panel and the laminate. The 5.1 cm (2 inches) tab was then folded around a triangular clip and stapled so that a weight could be attached to the test specimen. The sample thus prepared was allowed to dwell at room temperatures and approximately 50% relative humidity for approximately 72 hours. The test specimen was then placed in a Static Shear standard fixture having between zero and 2 degree angle back slant in a forced air oven set at 70° C. (158° F.). The test specimen was then given a 10 minute warm up period before attaching a 500 gram weight. The test was run until the test specimen failed or 10,000 minutes elapsed. Failure time and failure mode were recorded. Where the test specimen did not fail, the amount of slippage was measured and recorded.
Jaw Gap: 2.54 cm (1 inch)
Crosshead Speed: 25.4 cm/minute (10 inches/minute)
Two 12.5 mm (0.5 inch) wide by about 152 mm (6 inches) long strips were cut from the test sample such that the length was cut in the machine direction of the sample. Two strips were laminated side by side to a 50.8 mm (2 inch) wide×127 mm (5 inches) long×1.59 mm ({fraction (1/16)} inches) thick stainless steel panel such that the strips was centered down the middle of the panel with 1.27 cm (half inch) space between the strips and approximately 25.4 mm (1 inch) of the strip extends beyond the end of the panel. Care was taken to ensure maximum wet-out of or contact between the strip and the panel. It was desired that 100% contact be achieved. The bonded sample was allowed to dwell for between 24 and 72 hours at room temperature (about 22° C.). The free end of the test strips were pulled by hand at a speed of about 30 cm/minute (about 12 inches/minute) in a direction away from the panels to initiate stretch release removal until the bond failed. The test strips were pulled at an angle that was approximately between 10 and 25 degrees above the plane of the panel. The panels were then visually examined for the presence of residue and the number of times the strip broke.
Trade Designation Description Source
IRGACURE 651 2,2-dimethoxy-2-phenylacetophenone Ciba Specialty Chemicals
FR 370 tris(tribromoneopentyl) phosphate Dead Sea Bromine Group,
Beer Shiva, Israel
EXOLIT IFR 23 intumescent flame-retardant system Clariant Corporation,
based on ammonium polyphosphate Charlotte, NC
HL2081 rubber/resin pressure sensitive H. B. Fuller, St. Paul, MN
SYVALITE RE80HP tackifying resin Arizona Chemical,
ECR 180 tackifying resin ExxonMobil Chemical
Company, Houston, TX
EXACT 3040 ethylene-based hexene copolymer, ExxonMobil Chemical
nominal tensile yield strength (MD) Company, Houston, TX
5.4 MPa (780 psi), tensile break
elongation at break (MD) 460%, MI
16.5, density 0.900 g/cm3, Peak
Melting temperature 96° C. (205° F.).
General Preparation of Packaged Pressure Sensitive Adhesives I-III
Three pressure-sensitive adhesive compositions were prepared by mixing 2-ethylhexyl acrylate (2-EHA), acrylic acid (AA), 2,2-dimethoxy-2-phenylacetophenone (IRGACURE 651), and isooctyl thioglycolate (IOTG) in the amounts listed in Table 1 below. Each composition was formed into a “Packaged Pressure Sensitive Adhesive” by placing the composition into packages measuring approximately 100 mm by 50 mm by 5 mm thick as described in U.S. Pat. No. 5,804,610 (Hamer et al). The packaging film was 0.0635 mm (0.0025 inches) thick VA-24 film (a heat sealable, ethylene vinyl acetate copolymer film having 6% vinyl acetate, available from CT Film of Dallas, Tex.). The packages were immersed in a water bath and at the same time exposed to ultraviolet radiation at an intensity of 3.5 milliwatts per square centimeter and a total energy of 1627 millijoules per square centimeter as measured by NIST units to form a “Packaged Pressure Sensitive Adhesive (Pkg. PSA)”.
Parts by Parts by Parts by Parts by Wt. of
Wt. of Wt. of Wt. of 2,2-dimethoxy-2-
Component 2-EHA AA IOTG phenylacetophenone
Pkg. PSA I 90 10  0.03 0.15
Pkg. PSA II 97 3 0.01 0.15
Pkg. PSA III 95 5 0.01 0.15
Packaged Pressure Sensitive Adhesive IV
“Pkg. PSA I” was fed to the second feed port of a 30 mm co-rotating twin screw extruder (Werner Pfleider) operating at a screw speed of 300 rpm through a first 51 mm single screw extruder (Bonnot). The Bonnot zone temperatures were set at the following: Zone 1=149° C. (300° F.), Zone 2=163° C. (325° F.), and Zone 3=177° C. (350° F.). The pump and heated hose were set at 177° C. (350° F.). The temperature for the six zones in the twin screw extruder was set in Zone 1 at 163° C. (325° F.), and in Zones 2 through 6 at 121° C. (350° F.). The adhesive was delivered into a silicone coated paper box though a heated hose set at 121° C. (350° F.). The skin adhesive was identified as “Precompounded Adhesive A” as shown in Table 2 below.
A Pkg. PSA was fed at a rate of 12 lbs/hr (5.45 kg/hr) to Barrel Zone 1 of a 30 mm co-rotating twin screw extruder (Werner Pfleider) operating at a screw speed of 300 rpm through a first 51 mm single screw extruder (Bonnot). The Bonnot zone temperatures were set at the following: Zone 1=149° C. (300° F.), Zone 2=163° C. (325° F.), and Zone 3=177° C. (350° F.). The pump and heated hose were set at 177° C. (350° F.). The temperature for the six zones in the twin screw extruder was set at Zone 1=37.8° C. (100° F.), Zones 2=79.4° C. (175° F.), Zones 3=37.8° C. (100° F.), Zones 4=160° C. (325° F.), Zones 5=160° C. (320° F.), and Zone 6=160° C. (320° F.).
If present, the tackifying resin(s) was melted in a resin melting system, and was added into Barrel Zone 5. The resin melting tank temperature was set at 148.9° C. (300° F.), and the pump and heated hose were set at 162.8° C. (325° F.). The feed rate for both the fire retardant(s) and tackifying resin(s), if present, was adjusted based on the set 12 lbs/hour (5.45 kg/hr) flow rate of the Pkg. PSA to give the desired level of parts in the formulation as shown in Table 2.
The adhesive was delivered into a silicone coated paper box though a heated hose set at 160° C. (320° F.). The skin adhesives were identified as “Precompounded Adhesive C, D, E, F and G” as shown in Table 2 below.
Compo- Com- Precompounded Skin Adhesives, Parts by Wt.
nent Type ponent A B C D E F G
Adhesive Pkg. PSA 100
Pkg. PSA 100 100 100 100
Pkg. PSA 100
Tackifying ECR 180 39
Resin RE80HP 39 39 49
Fire EXOLIT 75 75 50
Retardant IFR 23
FR 370 49 49
Preparation of Compounded Core Adhesives H-N:
A Pkg. PSA was fed at a rate of 2.27 kg/hr (5 lb/hr) to Barrel Zone 1 of a 30 mm co-rotating twin screw extruder (Werner Pfleider) operating at a screw speed of 300 rpm through a first 51 mm single screw extruder (Bonnot). The Bonnot zone temperatures were set at the following: Zone 1=149° C. (300° F.), Zone 2=163° C. (325° F.), and Zone 3=177° C. (350° F.). The pump and heated hose were set at 177° C. (350° F.). The temperature for the six zones in the twin screw extruder was set at Zone 1=37.8° C. (100° F.), Zone 2=37.8° C. (100° F.), Zone 3=37.8° C. (100° F.), Zone 4=160° C. (320° F.), Zone 5=160° C. (320° F.), and Zone 6=160° C. (320° F.).
The core adhesives were identified as “Compounded Core Adhesive H, I, J, K, L, M, and N” as shown in Table 3 below. The Compounded Core Adhesive was not isolated but was fed to the middle layer of a three layer die as described below in Examples 1-11.
Compo- Com- Compounded Core Adhesive, Parts by Wt.
nent Type ponent H I J K L M N
Adhesive Pkg. PSA 100 100
Pkg. PSA 100 100 100
Fiber EXACT 54 54 54 54 54 65 87
Forming 3040
Fire EXOLIT 75 75 75
Compounded Core Adhesive H-N were combined with Precompounded Skin Adhesives A-G to prepare three layer tapes as follows:
After a core adhesive was compounded as described above, it was pumped directly through a heated hose to the center/middle layer of an about 203.2 mm (8 inches) wide, three layer CLOEREN die (available from The Cloeren Company, Orange, Tex.) with a gap of about 1 mm (0.040 inches). The die temperature was 320° F. (160° C.).
Simultaneously, a Precompounded Skin Adhesive was fed to the each of the outer layers of the die from a second 51 mm single screw extruder (Bonnot) and coextruded with the core adhesive extrudate above. The Bonnot zone temperatures were all set at 149° C. (300° F.). The pump and heated hose were set at 163° C. (325° F.). The skin adhesive flow rate was adjusted to provide a target thickness of each outer layer of 0.076 mm (3 mils). The process conditions were adjusted to provide the tape thickness set forth in Table 4. The extruded sheet was cast onto a chill roll that was set at 7.2° C. (45.5° F.), cooled to about 25° C., and then transferred onto a 0.127 mm thick polyethylene release liner prepared according to Examples 10a and 10b of copending U.S. patent application Ser. No. 09/775,955 “Adhesive Article and Method of Preparing.” The resulting article was wound into a roll for subsequent crosslinking.
of Skin Total
Skin Adhesive Thickness Total Tape Tape
Adhesive, Side 1/ of Core Thickness, Weight
Ex. Side 1/ Side 2, Core Layer, mm g/m2
No. Side 2 mm (mils) Layer mm (mils) (mils) (oz/yd2)
1 A/A 0.076/0.076 H 0.152 (6) 0.30 (12) 285.9
(3/3) (8.43)
2 A/A 0.076/0.076 H 0.229 (9) 0.38 (15) 379.5
(3/3) (11.19)
3 A/A 0.076/0.076 H 0.33 (13) 0.48 (19) 469.3
(3/3) (13.84)
4 B/B 0.076/0.076 I 0.305 (12) 0.46 (18) 338.0
(3/3) (9.97)
5 B/B 0.076/0.076 I 0.10 (4) 0.25 (10) 345.2
(3/3) (10.18)
6 C/C 0.076/0.076 J 0.38 (15) 0.53 (21) 592.1
(3/3) (17.46)
7 D/D 0.076/0.076 K 0.13 (5) 0.28 (11) 334.4
(3/3) (9.86)
8 E/E 0.076/0.076 L 0.13 (5) 0.28 (11) 318.8
(3/3) (9.40)
9 F/F 0.076/0.076 M 0.36 (14) 0.51 (20) 554.8
(3/3) (16.36)
10 G/G 0.076/0.076 M 0.20 (8) 0.36 (14) 410.3
(3/3) (12.10)
11 F/F 0.076/0.076 N 0.28 (11) 0.43 (17) 494.4
(3/3) (14.58)
Tensile Shear at
Break 90 Degree Adhesion, 70° C. Stretch
Strength, kN/m (piw) minutes, Release,
MPa % Shore A Stainless Boeing failure Sample 1/
Example (psi) Elongation Hardness Steel Composite mode Sample 2
1 0.059 710 49-30(e) 1.27 (7.26) 1.03 (5.89) >10,000 pass/fail(d)
(8.6) (1 break)
2 0.066 760 23 1.58 (9.00) 1.28 (7.34) >10,000 pass/pass
3 0.069 840 21 1.87 (10.7) 1.61 (9.19) >10,000 pass/pass
4 0.069 1270 41 1.86 NT(b) <1 C.(c) pass/pass
(10.0) (10.64)
5 0.048 1050 35 1.41 (8.04) NT <1 C. pass/pass
6 0.078 840 30 0.070 0.56 (3.21) 69 C. pass/fail
(11.4) (3.98) (2 breaks)
7(a) 0.019 600 21 0.84 (4.81) 0.92 (5.28) 43 C. fail/fail
(2.8) (5 breaks/
8 0.068 880 42 0.95 (5.45) 1.31 (7.51) >10,000 pass/pass
9 0.075 730 42 0.64 (3.68) 0.45 (2.59) 992 C. pass/fail
(10.9) (3 breaks)
10 0.070 720 50-48(e) 0.36 (2.06) 0.30 (1.73) >10,000 pass/pass
11 0.088 830 41 0.47 (2.71) 0.525 51 C. pass/pass
(12.9) (3.00)
(a)Example 7 was very poorly coated with void and bubbles in the construction which affected the test properties.
(b)NT = not tested.
(c)C = cohesive failure
(d)Presence of void in the core layer caused failure.
(e)Dial reading constantly decreased during testing; reading did not reach a level point.
For the 90 Degree Adhesion test, all samples detached cleanly from the surface of the test substrate without leaving a visible residue. Examples 4 and 5 have both rubber based skin adhesive layers and a rubber based adhesive core layer and would not be expected to have good shear at 70° C. The tensile break strength of the tape can be increased by increasing the concentration of the microfibers and/or the thickness of the core layer to prevent breaking during the Stretch Release Test for the tapes of Examples 1, 6, 7 and 9.
Examples 6-11 Flammability
The tapes of Examples 6-11 were tested for flammability according to Flammability Test Method. Data is set forth in Table 6.
Dripping Burn
Burn Flame Length,
Time, Time, mm Overall,
Example Drippings seconds seconds (inches) Pass/Fail
6 Yes 0 4.6 96.5 pass
7 Yes 0 13 139.7 pass
8 Yes 0 0 103.6 pass
9 Yes 0 >15 >203.2 fail
10 Yes 0 >15 >203.2 fail
11 Yes 0 >15 >203.2 fail
A fire retardant, cleanly removable carpet tape as shown in FIG. 3 was prepared as follows:
The skin adhesive is identified as “Compounded Skin Adhesive 0” and the core adhesive is identified as “Compounded Core Adhesive P”. Both the skin and core adhesives were not isolated, but were individually feed to a rotary die and coated onto a release liner.
Pkg. PSA II was fed at a rate of 2.27 kg/hr (5 lbs/hr) to Barrel Zone 1 of a 30 mm co-rotating twin screw extruder (Werner Pfleider) operating at a screw speed of 300 rpm through a first 51 mm single screw extruder (Bonnot). The Bonnot zone temperatures were set at the following: Zone 1=149° C. (300° F.), Zone 2=163° C. (325° F.), and Zone 3=177° C. (350° F.). The pump and heated hose were set at 177° C. (350° F.). The temperatures for the six zones in the twin screw extruder were set at Zone 1=37.8° C. (100° F.), Zones 2=37.8° C. (100° F.), Zones 3=37.8° C. (100° F.), Zones 4=160° C. (320° F.), Zones 5=160° C. (320° F.), and Zone 6=160° C. (320° F.).
The fire retardants, EXOLIT IFR 23 and FR 370, were added to Barrel Zone 3 using a KTRON weight loss feeder. The tackifying resin, RE 80 HP, was melted in a HELICONE resin melting system, and added into Barrel Zone 5. The HELICONE tank temperature was set at 148.9° C. (300° F.), and the pump and heated hose were set at 162.8° C. (325° F.). The feed rates for both the fire retardants, and tackifying resin were adjusted based on the set 2.27 kg/hr (5 lbs/hr) flow rate of the Pkg. PSA II to give the desired level of parts in the formulation as shown in Table 7 below.
After the skin adhesive was compounded as described above, it was not isolated, but pumped directly through a heated hose to an about 203.2 mm (6 inches) wide, rotary rod die set at about 160° C. (320° F.). It was coated directly onto a differential release, silicone coated, 55# densified kraft paper liner at target 0.125 mm (5 mils) thickness to provide Skin Adhesive Layer O, and wound into a roll.
Pkg. PSA III was fed at a rate of 1.36 kg/hr (3 lbs/hr) to Barrel Zone 1 of a 18 mm co-rotating twin screw extruder (Haake Micro 18, available from Haake, Karlsuhe, Germany) operating at a screw speed of 200 rpm through a first 51 mm single screw extruder (Bonnot). The Bonnot zone temperatures were all set at 121° C. (250° F.). The pump and heated hose were set at about 149° C. (300° F.). The temperatures for the zones in the twin screw extruder were all set at about 121° C. (250° F.).
The fire retardant FR 370 was added to Barrel Zone 3 using a weight loss feeder. The tackifying resin, RE 80 HP, was melted in a DYNAMELT S222-G29-24-ZN grid melting system, available from ITW Dynatec, Hendersonville, Tenn., and added into Barrel Zone 5. The grid was set at 148.9° C. (300° F.), and the pump and heated hose were set at 162.8° C. (325° F.). The feed rates for both the fire retardant, and tackifying resin were adjusted based on the set 1.36 kg/hr (3 lbs/hr) flow rate of the Pkg. PSA III to give the desired level of parts in the formulation as shown in Table 7 below.
After the skin adhesive was compounded as described above, it was not isolated, but pumped directly through a heated hose to an about 203.2 mm (6 inches) wide, rotary rod die set at about 149° C. (300° F.). It was coated directly onto a differential release, silicone coated, 55# densified kraft paper liner at target 0.125 mm (5 mils) thickness to provide a Core Layer P and wound into a roll.
Adhesive Composition, Parts
Component Adhesive Skin Adhesive
Type Component Layer O Layer P
Pkg. PSA II 100
Pkg. PSA III 100
Tackifying RE80HP 40 39
Fire EXOLIT 13.33
FR 370 66.67 49
Preparation of Fire Retardant, Multilayer Tape
Class 2 Result Requirement
A. Weight oz/yd2, max. 8.8 9.0
(a) Extinguish Time, sec., 12 15
(b) Burn Length, inches, 5.5 8
(c) Drip Extinguishing 0 5
C. Tensile Strength(a), lb/in, 29.5 30.0
(a)measured at a crosshead speed of 2.54 cm/min.
It is believed that use of a thicker polyester film in the above tape would provide a tape that would meet the tensile strength requirement.
Examples 1-3, 6-12 T-Peel Adhesion and 90 Degree Peel Adhesion
The tape of Example 12, along with the tapes of Examples 1-3, and 6-11, were tested for T-peel adhesion at room temperature(RT) and after aging at 70° C. for 72 hours; and 90 degree peel adhesion to Boeing floor panel BMS 4-2, Type II, from M.C. Gill, El Monte, Calif., at both room temperature and after aging for 72 hours at 70° C. Results are in Table 9.
T-Peel Adhesion to Panel, kN/m (piw)
Carpet Back, kN/m (piw) Failure Mode
Aged at Aged at of 70° C. Aged
Example RT 70° C. RT 70° C. Sample
1 0.11 (0.6) 0.14 (0.8) 1.04 (5.89) 2.08 stringy,
(11.81) cohesive of
2 0.14 (0.8) 0.16 (0.93) 1.29 (7.34) 2.2 (12.5) sl. stringy,
3 0.21 (1.2) 0.21 (1.2) 1.62 (9.19) 2.66 (15.1) stringy
6 0.14 (0.8) 0.13 (0.74) 0.57 (3.21) 0.65 (3.67) clean peel
7 0.25 (1.4) 0.37 (2.1) 0.93 (5.28) 0.94 (5.34) clean peel
8 0.07 (0.4) 0.09 (0.49) 1.32 (7.51) 0.77 (4.36) cohesive split
9 0.14 (0.8) 0.18 0.46 (2.59) 0.80 (4.56) clean peel
10 0 (0) 0 (0) 0.30 (1.72) 0.37 (2.1) clean peel
11 0.14 (0.8) 0.14 (0.78) 0.53 (3.0) 0.56 clean peel
12 0.14 (0.78) 0.15 0.38 (2.16) 0.47 (2.69) clean peel
From the data it can be see that for Examples 1-3, there is significant increase in adhesion to the Boeing floor panel after 70° C. aging compared to room temperature adhesion values. It is believed that this indicates better wet out of the substrate by these Examples compared to the other Examples tested. In addition, it is believed that Examples 1-3 would provide tapes that would be especially useful for general mounting applications where it is desirable to remove the tape after use. It is also believed that a decrease in the amount of fiber forming resin in Example 8 would improve the cohesive strength of the core.
US5851663 May 19, 1995 Dec 22, 1998 Minnesota Mining And Manufacturing Company Flame retardant pressure-sensitive adhesives and tapes
US5932298 Aug 17, 1998 Aug 3, 1999 Minnesota Mining And Manufacturing Company Methods of making packaged viscoelastic compositions
DE4222849A Title not available
DE4339604A1 Nov 20, 1993 May 24, 1995 Beiersdorf Ag Verwendung eines Streifens einer Selbstklebefolie für wiederablösbare Verklebungen
DE19723117A1 Jun 3, 1997 Dec 10, 1998 Beiersdorf Ag Verwendung eines doppelseitigen Klebebandes
WO2001014489A1 Aug 8, 2000 Mar 1, 2001 3M Innovative Properties Company Stretch releasing adhesive tape with segmented release liner
WO2001057152A2 Feb 2, 2001 Aug 9, 2001 3M Innovative Properties Company Adhesive for bonding to low surface energy surfaces
1 James M. Kobe et al, U.S. Appl. No. 09/775,955, filed Feb. 2, 2001.
2 Zhiming Zhou et al., U.S. Appl. No. 09/764,478, filed Jan. 17, 2001.
US7074494 * Feb 19, 2004 Jul 11, 2006 E. I. Du Pont De Nemours And Company Flame retardant surface coverings
US7744991 * May 30, 2003 Jun 29, 2010 3M Innovative Properties Company Thermally conducting foam interface materials
US8609242 * Dec 16, 2009 Dec 17, 2013 Utis Co., Ltd. Non-flammable cushioning and sealing sheet and method for preparing the same
US20050234169 * Jan 27, 2005 Oct 20, 2005 Kim Jang S Releasable adhesive composition
US20060182958 * Feb 14, 2006 Aug 17, 2006 Nitto Denko Corporation Pressure-sensitive adhesive tape and pressure-sensitive adhesive composition
US20080135159 * Dec 12, 2006 Jun 12, 2008 3M Innovative Properties Company Stretch releasing pressure-sensitive adhesive articles and methods of using the same
US20090253834 * Nov 11, 2008 Oct 8, 2009 E. I. Du Pont De Nemours And Company Adhesive compositions useful in flexible circuit substrate applications and methods relating thereto
US20110094667 * Aug 4, 2009 Apr 28, 2011 Tesa Se Method for producing strip laminates
WO2008141001A1 * May 6, 2008 Nov 20, 2008 3M Innovative Properties Company Multi-layer assembly, multi-layer stretch releasing pressure-sensitive adhesive assembly, and methods of making and using the same
U.S. Classification 428/354, 428/346, 428/40.1, 428/343, 428/345, 428/920, 248/205.3, 427/208.2, 427/208, 428/921, 427/208.4, 428/355.0AC
International Classification C09J11/00, B32B27/00, B32B7/06, C09J201/00, B32B5/00, C09J7/02, C09J9/00
Cooperative Classification Y10T428/2848, Y10T428/2813, Y10T428/28, Y10T428/14, Y10T428/2891, Y10T428/2809, Y10S428/92, Y10S428/921, C09J7/0207, C09J7/026, C09J2201/618, C09J2201/128, C09J9/00
European Classification C09J7/02K9, C09J9/00, C09J7/02F
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:NARUM, TIMOTHY N.;KOBE, JAMES J.;PEREYA, RODGER J.;AND OTHERS;REEL/FRAME:012778/0922