CA2122942A1 - Non-invasive adhesive process - Google Patents
Non-invasive adhesive processInfo
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- CA2122942A1 CA2122942A1 CA 2122942 CA2122942A CA2122942A1 CA 2122942 A1 CA2122942 A1 CA 2122942A1 CA 2122942 CA2122942 CA 2122942 CA 2122942 A CA2122942 A CA 2122942A CA 2122942 A1 CA2122942 A1 CA 2122942A1
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- sheet
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Abstract
A process for joining a porous sheet having at least one non-planar surface to an item is disclosed. The process includes the steps of: (1) providing an item; (2) providing a porous sheet having a first and second surface where at least the second surface has a non-planar configuration; (3) providing a material adapted, upon application of sufficient temperature, to substantially melt prior to either the item or the porous sheet significantly melting and which, when melted, forms an adhesive bond with both the item and the porous sheet; (4) placing the material on a surface of the item; (5) placing the first surface of the porous sheet on the material to form an item-material-porous sheet sandwich configuration; (6) applying sufficient heat to the sandwich configuration to melt the material without significantly melting the item or the porous sheet; (7) applying sufficient pressure to the sandwich configuration to distribute the melted material on the surface of the item and into, but not through, the pores of the porous material. As a result of the process, the first surface of the porous sheet is joined to the item without the non-planar configuration of the second surface of the porous sheet being adversely affected.
Description
NON-INVASlVE ADHESIVE PROCESS
- 21229~12 Field of the Invention This invention relates to a process for joining a sheet having at least one non-planar surface to an item.
Back~round of the Invention Releasablyengaging hookand loop type fasteners are well known and may be obtained under the trade designation VELCRO~. These fasteners are utilized in a wide variety of applications where two pieces of material are to be releasably joined to each other. Typical applications include shirt collar closures, on shoes as a substitute for shoe laces, at the cuffs of garments such as pants and shirts and in conjunction with the waist bands of garments for waist band adjustment. As is well known, the hook and loop type fasteners (sometimes referred to as hook and eye type fasteners) generally include two elements. The first element is typically a sheet having a multiplicity of fine hooks or their equivalents extending therefrom. The second element is typically a sheet having a multiplicity of fine loops, eyes or their equivalents extending upwardly therefrom. When the sheets are brought into contact with each other so that the hooks penetrate the eyes or loops, the hooks become ensnared within the eyes or loops. This secures the two sheets together. The joining of the two sheets or elements can be broken so as to again separate them by application of sufficient force as is well known in the art. The two 2 5 sheets can be joined and unjoined many, many times before degradation of the loops/eyes and/or hooks takes place to the extent to appreciably affect the strength of the juncture.
Disposable garments are well known to those in the art. Such garments include, for example, disposable diapers (see U.S. patent numbers 5,192,606 to Proxmire and 5,176,672 to Bruemmer et al.);
adult incontinent garments (see U.S. patent numbers 4,886,512 to Damico et al. and 4,747,846 to Boland et al.) and feminine hygiene products (see U.S. patent numbers 5,221,275 to Van Iten and 5,219,341 to Serbiak et al.).
Disposable garments such as, for example, disposable diapers have been manufactured for many years. Typically, the disposable diaper is manufactured in an hour-glass configuration which can be placed on an infant with the legs of the infant straddling the narrow 5 portion (the crotch portion) of the diaper and the top and bottom portions co-operating together to form the waist portion of the diaper as is well known in the art. Naturally, some means is necessary to join the top and bottom portions together to secure the waist portion of the diaper about the infant. In the past, a wide variety of adhesive tapes have been used to perform this function. A drawback of using adhesive tapes is that the number of times the tape can be removed and resecured is limited because either the tape bonds to the diaper too strongly and the tape tears the diaper upon its removal, or the tape leaves adhesive behind after each use and, eventually, the adhesive 15 bond formed is too weak to successfully maintain the proper position of the diaper on the baby, infant, or toddler.
The use of VELCRO~ fasteners with disposable diapers is known to those of skill in the art. See, for example, U.S. patent number 5,176,670 to Rossler et al. However, a problem which has been 2U encountered by those in the art is in the attachment of the loop/eye sheet to the disposable diaper. Typically, the loop/eye sheet is a nonwoven fibrous web which is quite porous. Use of a liquid adhesive to bond the porous sheet to the diaper body can lead to unsatisfactory results because, to be cost effective, the loop/eye sheet must be 25 applied and joined to the disposable diaper at the rapid rates of commercial manufacturing lines. Such an application involves an application of pressure to the "diaper-adhesive-loop/eye" sheet sandwich. This action, in many instances results in the adhesive being pressed through the loop/eye sheet and out onto the outer surface of - - 2122~2 the loop/eye sheet. Of course, the outer surface of the loop/eye sheet is the surface which should be able to releasably engage and disengage the hook laden sheet. The presence of the adhesive on the outer surface of the loop/eye sheet tends to foul or clog up the loops 5 and eyes. Thus, the function of the arrangement may be severely degraded, if not destroyed. Of course, this same problem exists when adhesive attachment of a loop/eye sheet to any other type of product is attempted. In like fashion, the problem is not solely limited to the joining of loop/eye sheets by adhesive means but rather to any porous 10 sheet having a desired non-planar surface which could be degraded if penetrated by an adhesive.
OBJECTS OF THE INVENTION
Accordingly, it is a general object of the present invention to provide a process for joining a loop/eye sheet portion of a VELCRO~
fastener to an item without the function of the loop/eye sheet being significantly adversely affected.
It is another general object of the present invention to provide a 20 process for joining a porous sheet having a non-planar outer functional outer surface to an item without the function of the non-planar outer surface being significantly adversely affected.
It is yet another object of the present invention to provide the products which are formed by the aforementioned processes.
Still further objects and the broad scope of applicability of the present invention will become apparent to those of skill in the art from the details given hereinafter. However, it should be understood that the detailed description of the preferred embodiment of the present invention is given only by way of illustration because various changes and modifications well within the spirit and scope of the invention 212~2 should become apparent to those of skiil in that art in view of the following detailed description.
SUMMARY OF THE INVENTION
In response to the aforementioned difficulties encountered by those of skill in the art, we have devised a process for joining a porous sheet having at least one non-planar surface to an item without fouling the non-planar surface. The process includes the steps of: providing the 10 item; providing the porous sheet having a first and second surface where at least the second surface has a non-planar configuration;
providing a material adapted, upon application of sufficient temperature, to substantially melt prior to either the item or the porous sheet significantly melting and which, when melted, forms an adhesive bond 15 with both the item and the porous sheet; placing the material on a surface of the item; placing the first surface of the porous sheet on the material to form an item-material-poroussheet sandwich configuration;
applying sufficient heat to the sandwich configuration to melt the material without significantly melting the item or the porous sheet and 20 applying sufficient pressure to the sandwich configuration to distribute the melted material on the surface of the item and into, but not through, the pores of the porous material. As a result of this process, the first surface of the porous sheet is joined to the item without the non-planar configuration of the second surface of the porous sheet being adversely 25 affected as by interpenetration of adhesive there into or through. Thus, the functionality of the non-planar second surface is preserved.
The number of items to which the present invention is applicable is virtually limitless. For example, the item may be a piece of wearing apparel, a disposable garment such as a diaper, a shoe or shoes, an 30 adult incontinent garment, a feminine hygiene product, furniture covers, - 21229~2 automobile covers, luggage and sporting equipment. The diaper may be disposable.
The porous sheet may be selected from a wide variety of such sheets well known to those of skill in the art. For example, the porous sheet may be selected from the group including meltblown webs, apertured films, spunbonded webs, dry laid webs and wet laid webs.
Furthermore, the porous sheet may be formed from any conventional substance which can be formed into a porous sheet. For example, the porous sheet may be formed from a substance selected from the group including polyolefins, nylons and polyesters. The polyolefin may be polyethylene, polypropylene or copolymers of either ethylene or propylene with other monomers. In one embodiment the non-planar configuration of the second surface of the porous sheet is formed by a plurality of loops adapted to releas~hly engage a plurality of hooks.
That is, the porous sheet is the loop or eye sheet of a VELCRO~ hook and loop/eye type of fastening system.
The material adapted, upon application of sufficient temperature, to substantially melt prior to either the item or the porous sheet significantly melting may be selected, in some embodiments, from the group including meltblown webs, films, spunbonded webs, dry laid webs and wet laid webs.
In some embodiments the sandwich configuration may be heated to at least about 155 degrees Centigrade (311 degrees F.). For example, the sandwich configuration may be heated to at least about 160 degrees Centigrade (320 degrees F.). More particularly, the sandwich configuration may be heated to at least about 177 degrees Centigrade (350 degrees F.).
- THE FIGURE
Figure 1 is a schematic rendering of a process for carrying out the present invention.
DETAILED DISCLOSURE
Turning now to the figure where like features are represented by like numerical reference numbers, and, in particular, it can be seen that Figure 1 is a schematic illustration o~ a process 10 for joining a porous sheet having a functional non-planar surface to an item without significantly adversely affecting the function of the non-planar surface of the sheet. Figure 1 illustrates an in-line process for this attachment where the item is, for example, the outer cover of a disposable diaper.
Of course, the item can be selected from a wide variety of structures such as, for example, wearing apparel, disposable garments, shoes, furniture, car covers, luggage, feminine hygiene products, adult incontinent products and safety equipment. Initially, the diaper outer cover material 12 is provided by a roll 14 and is transported to the nip 16 formed b~ two nip rollers 18 and 20. It may be necessary to support the outer cover material 12 by a conventional arrangement such as, for example, transport roller 22.
The porous sheet material having a functional non-planar surface 24 is provided by a ro!l 26. The porous sheet material 24 may be a sheet of the loop/eye material which is used in the manufacture of VELCRO~ type fastening systems. That is to say, the non-planar configuration of the surface of the porous sheet 24 can include a plurality of loops/eyes configured to releasably engage a plurality of hooks or equivalents thereto. Other examples of such porous sheets include meltblown webs, spunbonded webs, apertured films, dry laid webs and wet laid webs. All of these materials may be porous and 212Z9~2 have a non-planar surface or surfaces. If either one or both of these surfaces is formed to perform a function that would be degraded or ruined if an adhesive interpenetrated the surface, such a material would be a candidate for use in the present invention. The porous sheet 24 can be formed from a wide variety of material such as, for example, polyolefins, nylons and polyesters. Exemplary polyolefins include polyethylene and polypropylene. An exemplary polyethylene is linear low density polyethylene. The porous sheet 24 is, likewise, guided to the nip 16 of the nip rollers 18 and 20. Transport rolls 22 may be utilized to accomplish this guidance.
A roll 28 provides a sheet of strip 30 of a material adapted, upon application of sufficient temperature to substantially melt prior to either the item, such as the outer cover of the disposable diaper 12, or the porous sheet 24 significantly melting or heat degrading. The strip 30 also has the ability to, upon melting, form an adhesive bond with both the item 12 and the sheet 24. Exemplary forms of the strip 30 are films, meltblown webs, spunbonded webs, wet laid webs and dry laid webs.
It should be noted that the strip 30 need only be formed from a material having the aforementioned characteristics. Of course, the melting point characteristics required of the strip 30 will vary with the material from which the item 12 and the porous sheet 24 are formed. Exemplary materials from which the strip 30 can be formed include polyolefins, urethanes, Krayton0, Hytrel0, Arnitel~ and various compounded mixtures of these polymers with other materials.
Figure 1 illuslra~es that the nip 16 forms the item 12, the strip 30 and the porous sheet 24 into a "sandwich" configuration. Thereafter, the sandwich configuration is heated to a temperature high enough to substantially melt the strip 30 but not so high as to significantly melt or otherwise degrade the item 12 or the porous sheet 24. The heating of the sandwich is accomplished by a conventional heating element 32.
As has been previously stated, the degree of heating to which the sandwich need be subjected for the present invention to effectively operate will vary greatly with the materials from which strip 30 is made.
Naturally, the upper temperature to which the sandwich should be subjected will depend upon the melting point/degeneration point(s) of 5 the item 12 and the porous sheet 24. The upper limit will be the lower of these later two points. An exemplary temperature to which the sandwich can be heated if the strip 30 is formed from Krayton~D, the porous sheet 24 is formed from polyester and the item 12 is formed from polyethylene is at least about 155 degrees Centigrade (at least 10 about 311 degrees F.) For example, the sandwich may be heated to at least about 160 degrees Centigrade (at least about 320 degrees F.) More particularly, the sandwich may be heated to at least about 177 degrees Centigrade. (at least about 350 degrees F.) There are, no doubt, numerous mechanisms by which the strip 30 15 can be designed or formed so that it preferentially achieves a melted or, at least, a semi-molten state at a temperature which is less than the melting or degradation temperature of the item 12 and the porous sheet 24. The most readily recognizable way of achieving this result is for the material from which the strip 30 is formed to have a melting point which 20 is less than the melting point of either the item 12 or the porous sheet 24. For example, the melting point differential may be at least 10 degrees Centigrade (C.), (50 degrees F.) More particularly, the melting point differential may be at least 100 degrees C. (212 degrees F.) Even more particularly, the melting point differential may be at least 200 25 degrees C. (392 degrees F.) Once the sandwich has been heated to substantially melt the strip 30, and while the strip 30 is still in a semi-liquid state, pressure is applied to the sandwich by a pair of nip rollers 34 and 36. Passing the sandwich through the nip 38 formed by the nip rollers 34 and 36 forces 30 the semi-liquid strip 30 to slightly interpenetrate the porous sheet 24 without penetrating through the porous sheet 24 and onto the outer 21~29~
surface of the porous sheet 24. That is, the non-planar surface of the porous sheet 24 which does not face the strip 30 is not interpenetrated by the flowing strip 30. Thus, the function of this non-planar surface is not adversely affected by interpenetration of the flowing strip 30. Those of skill in the art will readily recognize that the amount of pressure applied by the nip rollers 34 and 36 will have to vary with a number of parameters including, for example, temperature applied and dwell time in the nip 38.
Because the strip material 30 also has the characteristic of being able to form an adhesive bond with both the item 12 and the porous sheet material 24, bonding of the porous sheet 24 to the item is effected by this process. Importantly, the function of the non-planar outer surface of the porous sheet material 24 is not adversely affected by interpenetration of the strip 30. Accordingly, in the situation where the item 12 is the outer cover of a disposable diaper and the porous sheet 24 is the loop/eye sheet of a VELCRO~ type fastening system, the loop/eye sheet is joined to the outercover material in such a manner that its function in co-operating with a hook sheet is not significantly affected.
Those of skill in the art will readily recognize that the heating and pressure applying steps can be performed simultaneously or the pressure applying step can be performed shortly after the heating step while the strip 30 is still in a semi-liquid state. After these steps have been performed, the item 12 with the porous sheet 24 attached thereto by way of the strip 30 is fed through a pair of transport rollers 40 and 42 and the composite sandwich is rolled up onto a supply roll 44.
Additionally, it should be recognized that certain of the process steps do not have to be done in an in-line fashion. For example, the strip 30 can first be joined to the porous sheet 24 so that a liquid impermeable backing for the porous sheet 24 is formed. This material can be wound up and stored until such time as it is desired to attach the porous sheet - 21229~2 24 to an item 12. Because the porous sheet 12 has now been provided with a liquid impermeable backing, a variety of different ways of attaching the porous sheet 24 to the item 12 are possible. Typically, the porous sheet 24 will be attached to the item 12 by heat sealing the backing strip 30 to the item 12. Alternatively, an adhesive can be utilized between the backing strip 30 and the item 12. Because of the presence of the liquid impermeable backing strip 30, the adhesive cannot interpenetrate through the porous sheet 24.
Further clarification of the present invention is afforded by reference to the following examples.
EXAMPLE I
In order to apply sufficient heat and pressure to the samples to be treated, an inverted hot plate was fabricated. The platen was provided with wooden handles and a 1/4 inch by 12 inch by 12 inch stainless steel plate was attached to the bottom of the assembly to act as the soleplate. Power to heat the soleplate was regulated by a variable autotransformer and the temperature of the soleplate was read by a contact thermocouple inserted through a well area of the platen.
A heat sink and working surface was provided by an aluminum plate approximately 20 inches by 15 inches by 5/8 inches in dimer~ion.
A sheet of silicon rubber about 1/32nd inch thick, 50 Shore A
durometer was placed over the plate. The sample to be treated was placed on the silicone sheet with the non-planar surface of the porous sheet against the silicone sheet. A sheet of ~.003 inch thick Teflon~
impregnated woven fiberglass cloth was placed over the sample to be treated and the heating platen was then passed over the cloth with an "ironing" motion.
A layer of loop/eye material (polyester 1.64 ounces per square yard (osy/, 55.o grams per square metertgsm)) obtained from the Gilford Mills Company of Greensboro, North Carolina, was placed on the -- 21229~
silicone sheet with the loop surface of the materiai against the silicone sheet. A layer of polypropylene meltblown web with a basis weight of 0.5 ounce per square yard (osy),16.95 grams per square meter (gsm) was placed over the loop material, and the fiberglass sheet placed over the combined sample. The platen was heated to 365 degrees F.,185 degrees C. and passed over the sample. The fiberglass sheet was removed leaving a composite material with one surface of engaging loops, and a second surface of smooth film-like nature. A stamp of VELCROh hook material one (1) inch by two (2) inches was repeatedly engaged and disengaged with the loop surface with no diminution in holding strength, and no visible deterioration in the integrity of the loop surface.
EXAMPLE ll This sample consisted of a layer of Gilford loop material (polyester 1.64 osy, 55.6 gsm) and a layer of polyethylene meltblown web (Dow Aspun 6814A) with a basis weight of 1.55 osy, 52.7 gsm. The sample was assembled and treated as described in Example I at 350 degrees F., 177 degrees C. for one (1) second. The sample after treatment showed the same properties as described in Example 1.
EXAMPLE lll In this sample the Gilford loop material (polyester 1.64 osy, 55.6 gsm~ was placed loop side on the silicone sheet. A layer of Krayton D
meltblown web (Shell Chemical 2.86 osy, 97.0 gsm) was placed over the loop material, and a layer of polyethylene film (Edison Plastic S/E
702) having a thickness of 0.5 mil (.0005 inch) placed over the meltblown web. The sample was treated as described in Example 1.
The sample after treatment at 350 degrees F.,177 degrees C. for one (1) second (as described in Example 1), was found to be a composite structure with the loop material securely bonded to the diaper film. The 21229~2 VELCRO~ hook stamp was engaged and disengaged as in Example 1.
In addition to the properties noted before, there was no separation of the bond between the loop material and the film.
While the invention has been described in detail with respect to 5 specific embodiments thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing, may readily conceive of alterations to, variations of and equivalents to these embodiments. Accordingly, the scope of the present invention should be assessed as that of the appended claims and all equivalents thereto.
- 21229~12 Field of the Invention This invention relates to a process for joining a sheet having at least one non-planar surface to an item.
Back~round of the Invention Releasablyengaging hookand loop type fasteners are well known and may be obtained under the trade designation VELCRO~. These fasteners are utilized in a wide variety of applications where two pieces of material are to be releasably joined to each other. Typical applications include shirt collar closures, on shoes as a substitute for shoe laces, at the cuffs of garments such as pants and shirts and in conjunction with the waist bands of garments for waist band adjustment. As is well known, the hook and loop type fasteners (sometimes referred to as hook and eye type fasteners) generally include two elements. The first element is typically a sheet having a multiplicity of fine hooks or their equivalents extending therefrom. The second element is typically a sheet having a multiplicity of fine loops, eyes or their equivalents extending upwardly therefrom. When the sheets are brought into contact with each other so that the hooks penetrate the eyes or loops, the hooks become ensnared within the eyes or loops. This secures the two sheets together. The joining of the two sheets or elements can be broken so as to again separate them by application of sufficient force as is well known in the art. The two 2 5 sheets can be joined and unjoined many, many times before degradation of the loops/eyes and/or hooks takes place to the extent to appreciably affect the strength of the juncture.
Disposable garments are well known to those in the art. Such garments include, for example, disposable diapers (see U.S. patent numbers 5,192,606 to Proxmire and 5,176,672 to Bruemmer et al.);
adult incontinent garments (see U.S. patent numbers 4,886,512 to Damico et al. and 4,747,846 to Boland et al.) and feminine hygiene products (see U.S. patent numbers 5,221,275 to Van Iten and 5,219,341 to Serbiak et al.).
Disposable garments such as, for example, disposable diapers have been manufactured for many years. Typically, the disposable diaper is manufactured in an hour-glass configuration which can be placed on an infant with the legs of the infant straddling the narrow 5 portion (the crotch portion) of the diaper and the top and bottom portions co-operating together to form the waist portion of the diaper as is well known in the art. Naturally, some means is necessary to join the top and bottom portions together to secure the waist portion of the diaper about the infant. In the past, a wide variety of adhesive tapes have been used to perform this function. A drawback of using adhesive tapes is that the number of times the tape can be removed and resecured is limited because either the tape bonds to the diaper too strongly and the tape tears the diaper upon its removal, or the tape leaves adhesive behind after each use and, eventually, the adhesive 15 bond formed is too weak to successfully maintain the proper position of the diaper on the baby, infant, or toddler.
The use of VELCRO~ fasteners with disposable diapers is known to those of skill in the art. See, for example, U.S. patent number 5,176,670 to Rossler et al. However, a problem which has been 2U encountered by those in the art is in the attachment of the loop/eye sheet to the disposable diaper. Typically, the loop/eye sheet is a nonwoven fibrous web which is quite porous. Use of a liquid adhesive to bond the porous sheet to the diaper body can lead to unsatisfactory results because, to be cost effective, the loop/eye sheet must be 25 applied and joined to the disposable diaper at the rapid rates of commercial manufacturing lines. Such an application involves an application of pressure to the "diaper-adhesive-loop/eye" sheet sandwich. This action, in many instances results in the adhesive being pressed through the loop/eye sheet and out onto the outer surface of - - 2122~2 the loop/eye sheet. Of course, the outer surface of the loop/eye sheet is the surface which should be able to releasably engage and disengage the hook laden sheet. The presence of the adhesive on the outer surface of the loop/eye sheet tends to foul or clog up the loops 5 and eyes. Thus, the function of the arrangement may be severely degraded, if not destroyed. Of course, this same problem exists when adhesive attachment of a loop/eye sheet to any other type of product is attempted. In like fashion, the problem is not solely limited to the joining of loop/eye sheets by adhesive means but rather to any porous 10 sheet having a desired non-planar surface which could be degraded if penetrated by an adhesive.
OBJECTS OF THE INVENTION
Accordingly, it is a general object of the present invention to provide a process for joining a loop/eye sheet portion of a VELCRO~
fastener to an item without the function of the loop/eye sheet being significantly adversely affected.
It is another general object of the present invention to provide a 20 process for joining a porous sheet having a non-planar outer functional outer surface to an item without the function of the non-planar outer surface being significantly adversely affected.
It is yet another object of the present invention to provide the products which are formed by the aforementioned processes.
Still further objects and the broad scope of applicability of the present invention will become apparent to those of skill in the art from the details given hereinafter. However, it should be understood that the detailed description of the preferred embodiment of the present invention is given only by way of illustration because various changes and modifications well within the spirit and scope of the invention 212~2 should become apparent to those of skiil in that art in view of the following detailed description.
SUMMARY OF THE INVENTION
In response to the aforementioned difficulties encountered by those of skill in the art, we have devised a process for joining a porous sheet having at least one non-planar surface to an item without fouling the non-planar surface. The process includes the steps of: providing the 10 item; providing the porous sheet having a first and second surface where at least the second surface has a non-planar configuration;
providing a material adapted, upon application of sufficient temperature, to substantially melt prior to either the item or the porous sheet significantly melting and which, when melted, forms an adhesive bond 15 with both the item and the porous sheet; placing the material on a surface of the item; placing the first surface of the porous sheet on the material to form an item-material-poroussheet sandwich configuration;
applying sufficient heat to the sandwich configuration to melt the material without significantly melting the item or the porous sheet and 20 applying sufficient pressure to the sandwich configuration to distribute the melted material on the surface of the item and into, but not through, the pores of the porous material. As a result of this process, the first surface of the porous sheet is joined to the item without the non-planar configuration of the second surface of the porous sheet being adversely 25 affected as by interpenetration of adhesive there into or through. Thus, the functionality of the non-planar second surface is preserved.
The number of items to which the present invention is applicable is virtually limitless. For example, the item may be a piece of wearing apparel, a disposable garment such as a diaper, a shoe or shoes, an 30 adult incontinent garment, a feminine hygiene product, furniture covers, - 21229~2 automobile covers, luggage and sporting equipment. The diaper may be disposable.
The porous sheet may be selected from a wide variety of such sheets well known to those of skill in the art. For example, the porous sheet may be selected from the group including meltblown webs, apertured films, spunbonded webs, dry laid webs and wet laid webs.
Furthermore, the porous sheet may be formed from any conventional substance which can be formed into a porous sheet. For example, the porous sheet may be formed from a substance selected from the group including polyolefins, nylons and polyesters. The polyolefin may be polyethylene, polypropylene or copolymers of either ethylene or propylene with other monomers. In one embodiment the non-planar configuration of the second surface of the porous sheet is formed by a plurality of loops adapted to releas~hly engage a plurality of hooks.
That is, the porous sheet is the loop or eye sheet of a VELCRO~ hook and loop/eye type of fastening system.
The material adapted, upon application of sufficient temperature, to substantially melt prior to either the item or the porous sheet significantly melting may be selected, in some embodiments, from the group including meltblown webs, films, spunbonded webs, dry laid webs and wet laid webs.
In some embodiments the sandwich configuration may be heated to at least about 155 degrees Centigrade (311 degrees F.). For example, the sandwich configuration may be heated to at least about 160 degrees Centigrade (320 degrees F.). More particularly, the sandwich configuration may be heated to at least about 177 degrees Centigrade (350 degrees F.).
- THE FIGURE
Figure 1 is a schematic rendering of a process for carrying out the present invention.
DETAILED DISCLOSURE
Turning now to the figure where like features are represented by like numerical reference numbers, and, in particular, it can be seen that Figure 1 is a schematic illustration o~ a process 10 for joining a porous sheet having a functional non-planar surface to an item without significantly adversely affecting the function of the non-planar surface of the sheet. Figure 1 illustrates an in-line process for this attachment where the item is, for example, the outer cover of a disposable diaper.
Of course, the item can be selected from a wide variety of structures such as, for example, wearing apparel, disposable garments, shoes, furniture, car covers, luggage, feminine hygiene products, adult incontinent products and safety equipment. Initially, the diaper outer cover material 12 is provided by a roll 14 and is transported to the nip 16 formed b~ two nip rollers 18 and 20. It may be necessary to support the outer cover material 12 by a conventional arrangement such as, for example, transport roller 22.
The porous sheet material having a functional non-planar surface 24 is provided by a ro!l 26. The porous sheet material 24 may be a sheet of the loop/eye material which is used in the manufacture of VELCRO~ type fastening systems. That is to say, the non-planar configuration of the surface of the porous sheet 24 can include a plurality of loops/eyes configured to releasably engage a plurality of hooks or equivalents thereto. Other examples of such porous sheets include meltblown webs, spunbonded webs, apertured films, dry laid webs and wet laid webs. All of these materials may be porous and 212Z9~2 have a non-planar surface or surfaces. If either one or both of these surfaces is formed to perform a function that would be degraded or ruined if an adhesive interpenetrated the surface, such a material would be a candidate for use in the present invention. The porous sheet 24 can be formed from a wide variety of material such as, for example, polyolefins, nylons and polyesters. Exemplary polyolefins include polyethylene and polypropylene. An exemplary polyethylene is linear low density polyethylene. The porous sheet 24 is, likewise, guided to the nip 16 of the nip rollers 18 and 20. Transport rolls 22 may be utilized to accomplish this guidance.
A roll 28 provides a sheet of strip 30 of a material adapted, upon application of sufficient temperature to substantially melt prior to either the item, such as the outer cover of the disposable diaper 12, or the porous sheet 24 significantly melting or heat degrading. The strip 30 also has the ability to, upon melting, form an adhesive bond with both the item 12 and the sheet 24. Exemplary forms of the strip 30 are films, meltblown webs, spunbonded webs, wet laid webs and dry laid webs.
It should be noted that the strip 30 need only be formed from a material having the aforementioned characteristics. Of course, the melting point characteristics required of the strip 30 will vary with the material from which the item 12 and the porous sheet 24 are formed. Exemplary materials from which the strip 30 can be formed include polyolefins, urethanes, Krayton0, Hytrel0, Arnitel~ and various compounded mixtures of these polymers with other materials.
Figure 1 illuslra~es that the nip 16 forms the item 12, the strip 30 and the porous sheet 24 into a "sandwich" configuration. Thereafter, the sandwich configuration is heated to a temperature high enough to substantially melt the strip 30 but not so high as to significantly melt or otherwise degrade the item 12 or the porous sheet 24. The heating of the sandwich is accomplished by a conventional heating element 32.
As has been previously stated, the degree of heating to which the sandwich need be subjected for the present invention to effectively operate will vary greatly with the materials from which strip 30 is made.
Naturally, the upper temperature to which the sandwich should be subjected will depend upon the melting point/degeneration point(s) of 5 the item 12 and the porous sheet 24. The upper limit will be the lower of these later two points. An exemplary temperature to which the sandwich can be heated if the strip 30 is formed from Krayton~D, the porous sheet 24 is formed from polyester and the item 12 is formed from polyethylene is at least about 155 degrees Centigrade (at least 10 about 311 degrees F.) For example, the sandwich may be heated to at least about 160 degrees Centigrade (at least about 320 degrees F.) More particularly, the sandwich may be heated to at least about 177 degrees Centigrade. (at least about 350 degrees F.) There are, no doubt, numerous mechanisms by which the strip 30 15 can be designed or formed so that it preferentially achieves a melted or, at least, a semi-molten state at a temperature which is less than the melting or degradation temperature of the item 12 and the porous sheet 24. The most readily recognizable way of achieving this result is for the material from which the strip 30 is formed to have a melting point which 20 is less than the melting point of either the item 12 or the porous sheet 24. For example, the melting point differential may be at least 10 degrees Centigrade (C.), (50 degrees F.) More particularly, the melting point differential may be at least 100 degrees C. (212 degrees F.) Even more particularly, the melting point differential may be at least 200 25 degrees C. (392 degrees F.) Once the sandwich has been heated to substantially melt the strip 30, and while the strip 30 is still in a semi-liquid state, pressure is applied to the sandwich by a pair of nip rollers 34 and 36. Passing the sandwich through the nip 38 formed by the nip rollers 34 and 36 forces 30 the semi-liquid strip 30 to slightly interpenetrate the porous sheet 24 without penetrating through the porous sheet 24 and onto the outer 21~29~
surface of the porous sheet 24. That is, the non-planar surface of the porous sheet 24 which does not face the strip 30 is not interpenetrated by the flowing strip 30. Thus, the function of this non-planar surface is not adversely affected by interpenetration of the flowing strip 30. Those of skill in the art will readily recognize that the amount of pressure applied by the nip rollers 34 and 36 will have to vary with a number of parameters including, for example, temperature applied and dwell time in the nip 38.
Because the strip material 30 also has the characteristic of being able to form an adhesive bond with both the item 12 and the porous sheet material 24, bonding of the porous sheet 24 to the item is effected by this process. Importantly, the function of the non-planar outer surface of the porous sheet material 24 is not adversely affected by interpenetration of the strip 30. Accordingly, in the situation where the item 12 is the outer cover of a disposable diaper and the porous sheet 24 is the loop/eye sheet of a VELCRO~ type fastening system, the loop/eye sheet is joined to the outercover material in such a manner that its function in co-operating with a hook sheet is not significantly affected.
Those of skill in the art will readily recognize that the heating and pressure applying steps can be performed simultaneously or the pressure applying step can be performed shortly after the heating step while the strip 30 is still in a semi-liquid state. After these steps have been performed, the item 12 with the porous sheet 24 attached thereto by way of the strip 30 is fed through a pair of transport rollers 40 and 42 and the composite sandwich is rolled up onto a supply roll 44.
Additionally, it should be recognized that certain of the process steps do not have to be done in an in-line fashion. For example, the strip 30 can first be joined to the porous sheet 24 so that a liquid impermeable backing for the porous sheet 24 is formed. This material can be wound up and stored until such time as it is desired to attach the porous sheet - 21229~2 24 to an item 12. Because the porous sheet 12 has now been provided with a liquid impermeable backing, a variety of different ways of attaching the porous sheet 24 to the item 12 are possible. Typically, the porous sheet 24 will be attached to the item 12 by heat sealing the backing strip 30 to the item 12. Alternatively, an adhesive can be utilized between the backing strip 30 and the item 12. Because of the presence of the liquid impermeable backing strip 30, the adhesive cannot interpenetrate through the porous sheet 24.
Further clarification of the present invention is afforded by reference to the following examples.
EXAMPLE I
In order to apply sufficient heat and pressure to the samples to be treated, an inverted hot plate was fabricated. The platen was provided with wooden handles and a 1/4 inch by 12 inch by 12 inch stainless steel plate was attached to the bottom of the assembly to act as the soleplate. Power to heat the soleplate was regulated by a variable autotransformer and the temperature of the soleplate was read by a contact thermocouple inserted through a well area of the platen.
A heat sink and working surface was provided by an aluminum plate approximately 20 inches by 15 inches by 5/8 inches in dimer~ion.
A sheet of silicon rubber about 1/32nd inch thick, 50 Shore A
durometer was placed over the plate. The sample to be treated was placed on the silicone sheet with the non-planar surface of the porous sheet against the silicone sheet. A sheet of ~.003 inch thick Teflon~
impregnated woven fiberglass cloth was placed over the sample to be treated and the heating platen was then passed over the cloth with an "ironing" motion.
A layer of loop/eye material (polyester 1.64 ounces per square yard (osy/, 55.o grams per square metertgsm)) obtained from the Gilford Mills Company of Greensboro, North Carolina, was placed on the -- 21229~
silicone sheet with the loop surface of the materiai against the silicone sheet. A layer of polypropylene meltblown web with a basis weight of 0.5 ounce per square yard (osy),16.95 grams per square meter (gsm) was placed over the loop material, and the fiberglass sheet placed over the combined sample. The platen was heated to 365 degrees F.,185 degrees C. and passed over the sample. The fiberglass sheet was removed leaving a composite material with one surface of engaging loops, and a second surface of smooth film-like nature. A stamp of VELCROh hook material one (1) inch by two (2) inches was repeatedly engaged and disengaged with the loop surface with no diminution in holding strength, and no visible deterioration in the integrity of the loop surface.
EXAMPLE ll This sample consisted of a layer of Gilford loop material (polyester 1.64 osy, 55.6 gsm) and a layer of polyethylene meltblown web (Dow Aspun 6814A) with a basis weight of 1.55 osy, 52.7 gsm. The sample was assembled and treated as described in Example I at 350 degrees F., 177 degrees C. for one (1) second. The sample after treatment showed the same properties as described in Example 1.
EXAMPLE lll In this sample the Gilford loop material (polyester 1.64 osy, 55.6 gsm~ was placed loop side on the silicone sheet. A layer of Krayton D
meltblown web (Shell Chemical 2.86 osy, 97.0 gsm) was placed over the loop material, and a layer of polyethylene film (Edison Plastic S/E
702) having a thickness of 0.5 mil (.0005 inch) placed over the meltblown web. The sample was treated as described in Example 1.
The sample after treatment at 350 degrees F.,177 degrees C. for one (1) second (as described in Example 1), was found to be a composite structure with the loop material securely bonded to the diaper film. The 21229~2 VELCRO~ hook stamp was engaged and disengaged as in Example 1.
In addition to the properties noted before, there was no separation of the bond between the loop material and the film.
While the invention has been described in detail with respect to 5 specific embodiments thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing, may readily conceive of alterations to, variations of and equivalents to these embodiments. Accordingly, the scope of the present invention should be assessed as that of the appended claims and all equivalents thereto.
Claims (17)
1. A process for joining a porous sheet having at least one non-planar surface to an item, the process comprising the steps of:
providing the item;
providing the porous sheet having a first and second surface where at least the second surface has a non-planar configuration;
providing a material adapted, upon application of sufficient temperature, to substantially melt prior to either the item or the porous sheet significantly melting and which, when melted, forms an adhesive bond with both the item and the porous sheet;
placing the material on a surface of the item;
placing the first surface of the porous sheet on the material to form an item-material-porous sheet sandwich configuration;
applying sufficient heat to the sandwich configuration to melt the material without significantly melting the item or the porous sheet;
applying sufficient pressure to the sandwich configuration to distribute the melted material on the surface of the item and into, but not through, the pores of the porous material;
whereby the first surface of the porous sheet is joined to the item without the non-planar configuration of the second surface of the porous sheet being adversely affected.
providing the item;
providing the porous sheet having a first and second surface where at least the second surface has a non-planar configuration;
providing a material adapted, upon application of sufficient temperature, to substantially melt prior to either the item or the porous sheet significantly melting and which, when melted, forms an adhesive bond with both the item and the porous sheet;
placing the material on a surface of the item;
placing the first surface of the porous sheet on the material to form an item-material-porous sheet sandwich configuration;
applying sufficient heat to the sandwich configuration to melt the material without significantly melting the item or the porous sheet;
applying sufficient pressure to the sandwich configuration to distribute the melted material on the surface of the item and into, but not through, the pores of the porous material;
whereby the first surface of the porous sheet is joined to the item without the non-planar configuration of the second surface of the porous sheet being adversely affected.
2. The process according to claim 1, wherein the item is selected from the group consisting of wearing apparel, disposable garments, shoes, furniture covers, automobile covers, luggage and sporting equipment.
3. The process according to claim 1, wherein the item is a diaper.
4. The process according to claim 1, wherein the item is a disposable diaper.
5. The process according to claim 1, wherein the item is an adult incontinent garment.
6. The process according to claim 1, wherein the item is a feminine hygiene product.
7. The process according to claim 1, wherein the porous sheet is selected from the group consisting of melt blown webs, apertured films, spunbonded webs, dry laid webs and wet laid webs.
8. The process according to claim 1, wherein the porous sheet is formed from a substance selected from the group consisting of polyolefins, nylons and polyesters.
9. The process according to claim 1, wherein the non-planar configuration of the second surface of the porous sheet is formed by a plurality of loops adapted to releasably engage a plurality of hooks.
10. The process according to claim 1, wherein the material is selected from the group consisting of meltblown webs, films, spunbonded webs, wet laid webs and dry laid webs.
11. The process according to claim 1, wherein the sandwich is heated to at least about 155 degrees Centigrade.
12. The process according to claim 1, wherein the sandwich is heated to at least about 160 degrees Centigrade.
13. The process according to claim 1, wherein the sandwich is heated to at least about 177 degrees Centigrade.
14. A process for joining a porous sheet having a non-planar surface comprising a plurality of loops adapted to releasably engage a plurality of hooks to an item, the process comprising the steps of:
providing the item;
providing the porous sheet which has a first surface and the non-planar surface;
providing a material adapted, upon application of sufficient temperature, to substantially melt prior to either the item or the porous sheet significantly melting and which, when melted, forms an adhesive bond with both the item and the porous sheet;
placing the material on a surface of the item;
placing the first surface of the porous sheet on the material to form an item-material-porous sheet sandwich configuration;
applying sufficient heat to the sandwich configuration to melt the material without significantly melting the item or the porous sheet;
applying sufficient pressure to the sandwich configuration to distribute the melted material on the surface of the item and into, but not through, the pores of the porous material;
whereby the first surface of the porous sheet is joined to the item without the ability of the loops to releasably engage a plurality of hooks being adversely affected.
providing the item;
providing the porous sheet which has a first surface and the non-planar surface;
providing a material adapted, upon application of sufficient temperature, to substantially melt prior to either the item or the porous sheet significantly melting and which, when melted, forms an adhesive bond with both the item and the porous sheet;
placing the material on a surface of the item;
placing the first surface of the porous sheet on the material to form an item-material-porous sheet sandwich configuration;
applying sufficient heat to the sandwich configuration to melt the material without significantly melting the item or the porous sheet;
applying sufficient pressure to the sandwich configuration to distribute the melted material on the surface of the item and into, but not through, the pores of the porous material;
whereby the first surface of the porous sheet is joined to the item without the ability of the loops to releasably engage a plurality of hooks being adversely affected.
15. A process for joining a porous sheet having a non-planar surface comprising a plurality of loops adapted to releasably engage a plurality of hooks to a disposable garment, the process comprising the steps of:
providing the garment;
providing the porous sheet which has a first surface and the non-planar surface;
providing a material adapted, upon application of sufficient temperature, to substantially melt prior to either the item or the porous
providing the garment;
providing the porous sheet which has a first surface and the non-planar surface;
providing a material adapted, upon application of sufficient temperature, to substantially melt prior to either the item or the porous
16 sheet significantly melting and which, when melted, forms an adhesive bond with both the garment and the porous sheet;
placing the material on a surface of the garment;
placing the first surface of the porous sheet on the material to form an garment-material-porous sheet sandwich configuration;
applying sufficient heat to the sandwich configuration to melt the material without significantly melting the item or the porous sheet;
applying sufficient pressure to the sandwich configuration to distribute the melted material on the surface of the garment and into, but not through, the pores of the porous material;
whereby the first surface of the porous sheet is joined to the garment without the ability of the loops to releasably engage a plurality of hooks being adversely affected.
16. The process according to claim 18, wherein the disposable garment is selected from the group consisting of a disposable diaper, an adult incontinent garment, a disposable training pant and a feminine hygiene product.
placing the material on a surface of the garment;
placing the first surface of the porous sheet on the material to form an garment-material-porous sheet sandwich configuration;
applying sufficient heat to the sandwich configuration to melt the material without significantly melting the item or the porous sheet;
applying sufficient pressure to the sandwich configuration to distribute the melted material on the surface of the garment and into, but not through, the pores of the porous material;
whereby the first surface of the porous sheet is joined to the garment without the ability of the loops to releasably engage a plurality of hooks being adversely affected.
16. The process according to claim 18, wherein the disposable garment is selected from the group consisting of a disposable diaper, an adult incontinent garment, a disposable training pant and a feminine hygiene product.
17. The process according to claim 18, wherein the disposable garment is a disposable diaper.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US17193793A | 1993-12-22 | 1993-12-22 | |
| US171,937 | 1993-12-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2122942A1 true CA2122942A1 (en) | 1995-06-23 |
Family
ID=22625710
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2122942 Abandoned CA2122942A1 (en) | 1993-12-22 | 1994-05-05 | Non-invasive adhesive process |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2122942A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2772779A1 (en) * | 1997-12-19 | 1999-06-25 | Ato Findley Sa | Hot-meltable moisture-curable adhesive for gluing fastener elements |
| FR2772780A1 (en) * | 1997-12-19 | 1999-06-25 | Ato Findley Sa | Moisture-curable polyurethane adhesive for gluing fastener elements |
| US7195692B2 (en) | 2000-08-11 | 2007-03-27 | Bostik Findley | Moisture-crosslinkable polyurethane adhesive for hygiene |
| CN111418951A (en) * | 2020-03-30 | 2020-07-17 | 江苏三尊新材料实业有限公司 | Automatic slipper production device and production process thereof |
-
1994
- 1994-05-05 CA CA 2122942 patent/CA2122942A1/en not_active Abandoned
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2772779A1 (en) * | 1997-12-19 | 1999-06-25 | Ato Findley Sa | Hot-meltable moisture-curable adhesive for gluing fastener elements |
| FR2772780A1 (en) * | 1997-12-19 | 1999-06-25 | Ato Findley Sa | Moisture-curable polyurethane adhesive for gluing fastener elements |
| WO1999032535A1 (en) * | 1997-12-19 | 1999-07-01 | Ato Findley S.A. | Moisture-setting polyurethane adhesive for hygiene articles |
| WO1999032568A1 (en) * | 1997-12-19 | 1999-07-01 | Ato Findley S.A. | Moisture-setting thermofusible adhesive based on polyurethane polymer |
| US7022804B2 (en) | 1997-12-19 | 2006-04-04 | Bostik Sa | Moisture-crosslinkable hot-melt adhesive based on polyurethane prepolymer |
| US7195692B2 (en) | 2000-08-11 | 2007-03-27 | Bostik Findley | Moisture-crosslinkable polyurethane adhesive for hygiene |
| CN111418951A (en) * | 2020-03-30 | 2020-07-17 | 江苏三尊新材料实业有限公司 | Automatic slipper production device and production process thereof |
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