MXPA00004299A - Nonwoven pressure sensitive adhesive tape - Google Patents

Abstract

A storage/dispensing assembly, e.g., a roll or stack, of non woven pressure sensitive adhesive tape comprising one or more multilayer sheets of pressure sensitive adhesive tape arranged such that the adhesive layer in the assembly of an overlying non woven pressure sensitive adhesive tape is in direct contact with the underlying nonwoven backing layer of non woven pressure sensitive adhesive tape. The non woven backing layer is formed at least in part of fibers having a denier of greater than 15 so as to decrease the level of fibers disengagement when an overlying nonwoven pressure sensitive adhesive tape is removed from the assembly.

Description

AN ADHESIVE TISSUE BELT SENSITIVE TO PRESSURE Field of the Invention The present invention relates to a fibrous non-woven adhesive tape sensitive to pressure specifically coated on one side with a pressure sensitive adhesive and disposed on one. similar pressure-sensitive adhesive tape coated with adhesive that does not have an intervening release element.

Background of the Invention U.S. Patent 5,605,729 discloses a storage / splitting assembly of a fastener fastening material used in a hook and loop fastening system comprising one or more multi-layered sheets of a fastener tape fastening material with one pressure-sensitive adhesive layer on one side of the fastener tape fastening material. The fastener tape fastening material is stored under conditions of Ref: 119593 splitting on a fastener tape fastening material such that it is in direct contact with the fastener layer of the lower fastener tape fastening material. When the upper fastener tape fastening material is separated from the lower corrugated fastening material, the fasteners of the lower fastener tape fastening material are in a latchable condition. The fastener tape fastening material geney comprises a corrugated layer comprising a multiplicity of flexible fasteners and a lower base layer on which the fasteners are fixed and a pressure sensitive adhesive layer on an opposite surface of the fastener. base layer. A variety of suitable fastener materials are described, among which are woven materials, interwoven materials, stitched materials or non-woven materials. As an example, there is mentioned a woven cloth or loop coil of textured polyester coated by extrusion with polypropylene and subsequently coated with a pressure sensitive adhesive of a viscous styrene-butadiene block copolymer. The example of a polypropylene loop fabric with thermo-joined spun bond to the molten film of an ethylene-propylene impact copolymer resin is also mentioned, the film of which is coated on the opposite side with a viscous adhesive "KRATON" 1111 (an adhesive based on a block copolymer of styrene-isoprene-styrene). This belt loop construction has been considered as quite advantageous in terms of its manufacturability, coil stability, ease of use, and performance. However, with fibrous nonwoven web tape materials, the fibers of a lower corrugated web material tend to disengage from the backing material or base layer when the fastening material is removed from the top corrugated web. This disengagement of the fiber can decrease the level of adhesion of the pressure sensitive adhesive layer of the upper loop tape when it is subsequently fixed to a substrate and / or decreases the adhesion of the loop to the hook with the lower corrugated belt material. In gene it is advisable to minimize this level of fiber release.

The formation of a pressure-sensitive adhesive tape from a woven or non-woven fibrous fabric is also known. With non-woven tape support, geney the non-woven fibers should be provided with sufficient fastening such that they do not come loose when the tape is fractioned into a coil without a release liner separating each turn of the tape spool. The fibers are fixed with adhesive materials, binding fibers, calendering, overlays or combinations thereof. However, these treatments geney produce an adverse effect on the formability, sponginess or solidity, and the feel of the supports. In gene it is advisable to provide a non-woven tape support that can be rolled without the need for high levels of interfiber bonding or overlapping layers.

Brief description of the invention.

A non-woven pressure-sensitive adhesive tape assembly comprising one or more multilayer sheets of non-woven pressure-sensitive adhesive tape is provided comprising, in order: (1) a non-woven backing layer forming its first major surface, and (2) a pressure sensitive adhesive layer forming its second main surface.

The non-woven backing layer is formed at least in part by fibers or filaments having a denier of at least 15, the fibers of which do not generally have binders or aggregate bonding fibers. The non-woven pressure-sensitive adhesive tape has an arrangement in such a set that the adhesive layer of a top non-woven pressure-sensitive adhesive tape is in direct contact with the non-woven backing layer of a pressure-sensitive adhesive tape. non-woven bottom.

Brief Description of the Drawings.

The invention will be explained in more detail with reference to the drawings, wherein: Figure 1 is a cross section of a portion of an embodiment of a storage / fractionation assembly of the invention; Fig. 2 is a side view of another embodiment of a storage / fractionation assembly of the invention with a portion of the adhesive tape sensitive to fractional pressure; and Figure 3 is a cross section of a fractional pressure sensitive adhesive tape of Figure 2.

These figures, ideals, are not representations in scale and with them we try to be merely illustrative and not limitative.

Detailed description of the invention.

Figure 1 shows an assembly of the non-woven pressure sensitive adhesive tape illustrative of the invention. The assembly 10 shown comprises a stack of three multilayer sheets 12a. 12b, 12c of a non-woven pressure sensitive adhesive tape. However, the assemblies of the invention can have an indefinite number of layers according to the width of the non-woven pressure-sensitive adhesive tape and the shape of the pile or endless coil. The pressure sensitive adhesive tape 12 comprises, in order: (1) the non-woven backing layer 14 forming its first main surface, and (2) the pressure sensitive adhesive layer 18 forming the second main surface of the tape. pressure sensitive adhesive 12. The non-woven pressure sensitive adhesive tape is disposed in the assembly 10, such that the adhesive layer 18a of the upper non-woven pressure sensitive adhesive tape is in direct contact with the carrier layer 14b of a lower non-woven pressure sensitive adhesive tape.

The non-woven pressure-sensitive adhesive tape used in the assemblies of the invention can be manufactured with a variety of non-woven materials such as spunbonded non-woven materials, melted and blown non-wovens, carded fabrics, non-woven fabrics woven by air, non-woven perforated with needle, twisted cord non-woven, suitable combinations of the foregoing and the like.

For many applications, the non-woven pressure-sensitive adhesive tape used in conjunction with the invention will have a total basis weight of between 1 and 20 ounces / yard2 (34-678 grams / meter ro2) approximately, it will be made of polyolefin filaments , (for example, polypropylene) polyester, naylones or combinations of said materials.

In accordance with the present invention, it has been found that when a given percentage of non-woven backing material is formed from filaments or fibers having an average denier of at least 15 less fibers are removed significantly from the backing when the backing is removed. upper non-woven pressure sensitive adhesive tape of the set. However, in general, the fibers require fixing which is usually carried out by the use of a backing layer between the non-woven backing layer and the adhesive layer where the fibers of the non-woven backing layer are bonded to the backing layer., or are incorporated within, the support layer. Preferably, this backing layer is a continuous film which also prevents adhesive migration of the adhesive layer on and through the non-woven backing layer. This causes a minor contamination of the adhesive of the upper non-woven pressure sensitive adhesive tape and a corresponding better adhesive to the substrates to which this corrugated tape fastening material is subsequently applied. Generally, the nonwoven backing material should have at least 25 weight percent (preferably 50 to 100 weight percent) of fibers with a denier of 15 to 50, preferably 15 to 30, with the remainder of fibers comprised with a denier of less than 15, preferably from 3 to 9.

As set forth below, it may be preferable to specifically control the adhesion between the non-woven backing layer 14 and the adhesive layer 18 to achieve the desired release properties of the upper pressure sensitive adhesive tape in the assembly. The control of the adhesive and the release properties of the non-woven pressure-sensitive adhesive tape in the assembly can be carried out by means of a variety of techniques. First, the adhesive 18 can be chosen for its specific adhesion characteristics with respect to a selected non-woven backing layer 14. Secondly, the support layer 14 can be chosen specifically by its specific interaction with the selected adhesive. The material of the non-woven backing layer 14 can exhibit the desired release characteristics in inert form or the release properties of the backing layer can be modified, for example, by the incorporation of a release control agent (e.g. , as an additive in a polymeric composition or by means of graft polymerization) in the fibrous material from which the support is made and / or the application of a release control agent on the surface of the nonwoven support, prior to the introduction of non-woven pressure-sensitive adhesive tape in the assembly. Among the examples that illustrate the release control agents incorporated in the tape, there are the additives of molten polymer or graft polymerization such as for example the grafted polymorphonucleic polymer presented in PCT patent application No. WO 92/15626 (Rolando and collaborators), etc. Examples illustrating surface-applied release agents (i.e., topicals) include urethanes such as those presented in U.S. Patent No. 2,532,011 (Dahlquist et al.), Reactive silicones, luorochemical polymers , exhibits of the form presented in the U.S. Patents Nos. 4,313,988 (Bany et al.) and 4,482,687 (Kessel et al.), block copolymers of poliorganos and loxane-polyurea in the form presented in the application of the European Patent No. 250,248 (Leir et al.), etc.

Preferably the adhesion of the adhesive layer to the upper non-woven backing layer is preferably low enough so that the fibers of the non-woven backing layer do not substantially detach from the non-woven backing layer when the adhesive layer is separated therefrom. This effect is substantially aided by the use of fibers or filaments having a denier of at least 15 in the concentration variations described above in the non-woven support layer. If a substantial amount of fibers do not remain fixed to the non-woven backing layer and are released, the dislodged fibers may tend to contaminate the top adhesive layer and degrade its adhesion properties.

Figure 2 illustrates other embodiments of the invention wherein the storage / fractionation assembly 20 is a coil comprising one or more multilayer sheets of pressure-sensitive adhesive tape of the previously described shape wound around the core itself 22. However, as it is shown, the pressure-sensitive adhesive tape wound concentrically and generally aligned, the successive paths of the pressure-sensitive adhesive tape can be rolled in any suitable manner by half of a level winding or similar.

Commonly, the top adhesive layer exhibits a peeling force relative to the non-woven backing layer of between about 4 and about 400 grams / centimeter-width, preferably between about 8 and about 120 grams / centimeter-wide, and more preferably between 8 and 80 grams / cent imet ro-width approximately. As experts in the art will appreciate, embodiments of the present invention can be performed with detachment forces out of those variations, if desired. However, commonly, the detachment force should be less than the internal tearing strength of the non-woven backing layer 14 or the pressure sensitive adhesive tape such that the pressure-sensitive adhesive tape can be prepared to easily be divided from the set. in a usable form. The pressure-sensitive adhesive tape in a coil commonly shows an unwinding force of between 4 and 250 grams / centimeter approximately ro-width, and preferably between 8 and 120 grams / centimeter imet ro-width approximately.

The adhesive layer 18 of the pressure sensitive adhesive tape of the present invention is a pressure sensitive adhesive. The selection of a suitable adhesive will be based in part on factors such as the substrate to which the pressure-sensitive adhesive tape is to be fixed, the nature of the backing layer, the desired properties of the pressure-sensitive adhesive tape 12, the conditions of use to which the pressure sensitive adhesive tape 12 will be exposed, and the available transformation techniques and the equipment for removing the pressure sensitive adhesive tape 12 from the storage / fractionation and conversion assembly, for example, by means of the Normal cut or in strips to the desired format. The adhesive layer 18 should become tacky at room temperature, adhere to the substrates in question to which the pressure-sensitive adhesive tape 12 is to be applied, adhere well to the support 16 or to the base layer of the pressure-sensitive adhesive tape. Those skilled in the art can select the appropriate adhesives for specific applications. Examples illustrating suitable adhesives include: acrylates, viscous natural rubber, viscous synthetic rubber resins, etc. The adhesive layer can be substantially continuous or a design can be applied, if desired. Suitable adhesives can be easily selected by those skilled in the art.

The pressure sensitive adhesive is preferably a viscosified elastomer wherein the elastomer is a block copolymer of the type A-B wherein the block A and the B blocks are configured in a linear, radial or star shape. The block A is formed by a monoalqueni lareno, preferably by a polystyrene block having a molecular weight of between 4,000 and 50,000, preferably between 7,000 and 30,000. The content of block A is preferably between 10 and 50 weight percent, preferably about 10 to 30 weight percent of block copolymer. Other suitable A blocks can be formed with the fa-methylstyrene, t-butyl-styrene and other ring alkylated styrenes, as well as mixtures thereof. Block B is formed by an elastomeric conjugated diene, generally of poly soporine having an average molecular weight of between about 5,000 and 500,000, preferably between about 50,000 and 200,000. The content of block B is, in general, from 90 to 500 percent, preferably from 90 to 70 percent by weight. The viscosifying components for the elastomeric base adhesives generally comprise a solid viscous resin and / or a liquid or plasticiser or plasticizer. Preferably, the viscosifying resins are selected from the group of resins at least partially, compatible with the portion of the B block of polydiene of the elastomer. Although not preferably, generally, a relatively lower amount of the viscosifying resin may include resins compatible with block A, which, if present, are termed terminal block reinforcing resins. In general, the terminal block resins are formed by aromatic monomer species. Suitable liquid plasticizers or plasticizers for use in the adhesive composition for the tape of the fastening tape include naphthenic oils, paraffin oils, aromatic oils, mineral oils or rosin esters, polyterpenes and molecular weight C-5 resins. low. Among the solid resin resins are the C-5 resins, the resins resins, the polyterpenes and the like.

The viscosifying portion of the pressure sensitive adhesive generally comprises from 20 to 300 parts per 100 parts of the elastomeric phase. Preferably, this is a solid viscosifier for the most part; however, from 0 to 25 weight percent, preferably from 0 to 10 weight percent of the adhesive, may be a liquid catalyst and / or plasticizer.

In general, an additional layer needs to be provided between the non-woven backing layer and the adhesive layer. Figure 1 shows other support layers 16.

Additional support layers 16 could be placed between the non-woven backing layer and the adhesive layer and could be other non-woven layers, film layers, paper, woven layers, or the like. In particularly preferred embodiments, the non-woven backing layer of pressure sensitive adhesive tape has an extrusion bonded film in the form of an additional layer, as it is presented in U.S. Patent No. 5,256,231. In this case, the nonwoven support material would be fed in a contact line formed between two nested surfaces, such as for example two geared coils rotating at the same time. The material of the non-woven backing layer and the thermoplastic backing layer in melt state are placed on the contact line from a die, with an optional additional support or another layer on the opposite side of the molten thermoplastic backing layer. The pressure applied by the contact line causes the fibers of the non-woven backing layer to be impregnated with the thermoplastic support.

Sometimes, the additional support layers 16 are used to impart or define on a large scale, part of the tensile strength of the non-woven pressure sensitive adhesive tape 12. In most embodiments, any additional support layer it would have a thickness of between approximately 5 and 12,500 microns, with the thicknesses of foam-type supports generally being greater. When the support is, for example, a polyolefin sheet, the common thickness will be between about 25 and 500 microns, sometimes between 50 and 250 microns. It is understood that supports of other thicknesses different from this range, may be required in some cases.

Test methods Proof of fiber lamination: Adhesion of detachment at 180 degrees and retention of detachment at 90 degrees.

The fiber delamination test was used to examine the release and subsequent contamination of the pressure sensitive adhesive of the nonwoven fastening tape.

A piece of 2 inch by 5 inch non-woven fastening tape was firmly placed to test it with the adhesive side down on a 2-inch by 5-inch steel panel (5.08) centimeters by 12.7 cm.). Then, a 1 inch (2.54 cm) wide strip of test pressure-sensitive adhesive tape was placed in the center with a paper guide over the non-woven material so that the leading edge of the Adhesive tape will run the length of the panel. The test adhesive tape was a pressure-sensitive adhesive of block copolymer of the type iodine-i soprene vi scosi fi ed (XMF-4065 sold by 3M Company). The sample was rolled by hand, once in each direction, using a roller of 11 pounds (5.3 kg). Then, the sample panel was placed in the lower jaw of an Intron® tensile tester at constant speed of the extension. Without previously detaching the sample, the end of the paper guide was placed in the upper jaw of the tensile tester so that the guide was taut. At a crosshead speed of 12 inches (30.5 cm.) Per minute, a payroll record was used to record the detachment that was maintained at 180 degrees. The load required to remove the test tape from the non-woven surface of the fastening tape was recorded. The results indicated in the Table are expressed in grams / 2, 54 cm wide. The values represent an average of at least two independent measurements.

To examine the extent to which the viscosity of the pressure-sensitive adhesive had been removed due to the transfer of fibers from the non-woven material, the contaminated tape (ie the tape that had been adhered to the non-woven material) was tested for a readherence by detachment at 90 degrees from a smooth polyethylene film surface. Next, the 90 degree detachment test is described.

Readherence by detachment at 90 degrees: A piece of a 330 micron smooth polyethylene film was firmly fixed to a steel panel measuring 2 inches by 5 inches (5.1 cm by 12.7 cm) using a double-stick adhesive tape. The contaminating test adhesive tape was placed in the center against the surface of the polyethylene film and the tape was wound together with two passes of a 100 gram rubber roller. The panel was placed in a device that was then placed in the lower jaw of an Instron® tensile tester at constant speed while the upper jaw held the release tape. The upper jaw was operated at a constant crosshead speed of 12 inches (30.5 cm.) Per minute while moving the steel panel to hold the release belt at a 90 degree angle to the panel. The tests were carried out at a constant temperature of 21 ° C and a relative humidity of 50 percent. The force required to remove the contaminated tape from the polyethylene film was recorded as the readherence value. The data related to the readherence of the Table were recorded in grams / 2, 5 centimeter-wide. The results represent an average of at least two independent measurements.

E j emplos Examples 1 and 2, and Comparative Example 3 The non-woven fastening tapes were prepared by first extrusion coating with a polypropylene resin (N 7C50, an impact copolymer of polyethylene and polypropylene commercialized by Union Carbide) on a non-woven fabric bonded with a carded design to provide a thermoplastic support layer. The basis weight of the thermoplastic support layer of the examples was about 55-60 grams / meter2. The carded non-woven fabrics had a rhombus-shaped design with diamonds of approximately 4 mm in width between the opposite angles of the rhombus having joint portions of approximately 1 mm in width. The following table summarizes the types and sizes of fiber that were used to prepare the carded non-woven fabrics. The basis weights of the non-woven fabrics carded for the examples were about 45-48 grams / met ro2.

The side of the carded non-woven fabric of the material was corona treated to obtain a surface energy of about 33 dynes / centimeter and then coated with the release material. The release material used was a release material of the polyorganic copolymer type and loxanopol iurea similar to those described in U.S. Patent No. 5,290,615. The coating thickness of the release material was approximately 0.4-0.8 grams / meter2. Then, a hot melt pressure sensitive adhesive was coated on a thermoplastic backing layer. The adhesive used was the same viscosity-isoprene-viscous type block copolymer pressure sensitive adhesive that was used in the test adhesive tape in the fiber delamination test described above. The thickness of the adhesive coating was approximately 38 microns. Then, the non-woven fastening tape without a release liner was rolled on itself.

The examples were tested in terms of Fiber De-lamination according to the test method described above. The table summarizes the results obtained.

Table Examples Type and size of Adherence by Readherence for fiber detachment to detachment at 180 ° polyethylene at 90 ° 1 18 denier J32c 109 770 2 15 denier T-1822 202 722 C 3 9 denier T-1962 1510 33 J32 are polypropylene fibers that have a fiber length of 1 7/8 inch (4.76 cm) which are marketed by I love co. 2T-196 and T-182 are polypropylene fibers having a fiber length of 1778 inches (4.76 cm) which are marketed by Hercules Inc.

Peel adhesion values considerably greater than 180 were obtained for the example (C3) that was prepared with the lower denier fibers compared to those that were prepared with higher denier fibers (Examples 1-2).

From this it follows that the pressure-sensitive adhesive adheres so firmly to the fibers with lower denier that contamination of the fiber of the adhesive layer on the upper non-woven fastening tape is carried out when it is removal of the material from the lower non-woven fastening tape. This results in contamination of the adhesive fiber of the upper nonwoven tape and its corresponding decrease in the adhesion of the nonwoven fastening tape to the substrates. This was reaffirmed by the data relating to the readherence since the value of readherence by detachment at 90 degrees was markedly lower (essentially non-functional) for the example that was prepared with lower denier fibers.

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 (1)

1. Claims A set of non-woven pressure-sensitive adhesive tape comprising one or more multilayer sheets of non-woven pressure-sensitive adhesive tape comprising, in order: (1) a support having a non-woven layer forming the first major surface of the pressure sensitive adhesive tape, and (2) a pressure sensitive adhesive layer forming the second major surface of the pressure sensitive tape.; characterized in that the non-woven backing layer is formed at least in part, by fibers having a denier of at least 15, and the non-woven pressure sensitive adhesive tape is disposed in the set such that the adhesive layer of a sensitive adhesive tape at the upper non-woven pressure it is in direct contact with the non-woven backing layer of a lower non-woven pressure sensitive adhesive tape. The assembly according to claim 1 further characterized in that the adhesive layer of the upper non-woven pressure sensitive adhesive tape exhibits a peeling force with respect to the lower non-woven backing layer of between 4 and 250 grams / centimeter in width , approximately . The assembly according to any of claims 1 or 2 further characterized in that the adhesive layer of adhesive tape sensitive to the upper non-woven pressure shows a peeling force with respect to the lower non-woven support layer of between 8 and 80 grams / centimeter. ro-width, approximately. The assembly according to claim 1, characterized in that the assembly is a coil comprising one or more of the sheets of non-woven pressure-sensitive adhesive tape wound on itself, wherein the sheet of pressure-sensitive adhesive tape Nonwoven that is in the coil, shows unwinding force between 4 and 250 grams / centimeter ro-width. The assembly according to claim 1, characterized in that the sheet comprises a detachment control people incorporated or applied to the non-woven backing layer prior to the placement of the non-woven pressure-sensitive adhesive tape in the joint. The assembly according to any of claims 1 to 5, characterized in that the support comprises an additional support layer joined between the non-woven support layer and the adhesive layer. The assembly according to any of claims 1 to 6, characterized in that the non-woven support layer comprises: a) from 25 to 100 weight percent fiber representing a denier from 15 to 50; b) from 0 to 75 weight percent of fibers having a denier of less than 25. The assembly according to any of claims 1 to 7, characterized in that the nonwoven support layer comprises: a) from 50 to 100 weight percent of fibers having a denier of 15 to 30; b) from 0 to 50 weight percent of fibers having a denier of less than 25. The assembly according to any of claims 1 to 8, characterized in that the pressure-sensitive adhesive comprises a modified elastomer wherein the elastomer is a block copolymer of the type AB wherein the block A is formed by a mono-a lqueni 1 isne and block B is formed by a conjugated diene wherein the content of block A is from 10 to 50 weight percent and the content of block B is from 90 to 50 weight percent of the vi scosi fier comprising from 20 to 300 parts by weight of the viscosi fi er to 100 parts of elastomer. The assembly according to any of claims 1 to 9, characterized in that the viscosifier comprises a liquid resin, a solid resin, and / or a plasticizer at least in part, compatible with block B, and block A comprises from 10 to 30 percent by weight of the elastomer and block B comprises from 90 to 70 weight percent of the block copolymer and the viscosifier is mostly a solid matrix resin.