ADHESIVE CROSS-LAMINATED THERMOPLASTIC NET-LIKE WEB AND METHOD OF FABRICATION THEREFOR
PATENT COOPERATION TREATY APPLICATION IN THE UNITED STATES PATENT AND TRADEMARK RECEIVING OFFICE
Be it known that I, Paul N. Antonacci, residing at 3061 Vinings Ridge Drive, Atlanta, Georgia 30339, and I, Bill Cook, residing at 103 Plymouth Drive, LaGrange, Georgia 30240, citizens of the United States, and I, Kintaro Aihara, residing at 671 County Road 17, Roanoke, Alabama 36274, and I, Hiroyoshi Yoneta, residing at 106 Brooksong Way, Peachtree City, Georgia 30269, citizens of Japan, have invented certain new and useful improvements in an Adhesive Cross-Laminated Thermoplastic Net- Like Web and Method of Fabrication Therefor of which the following is a specification. CROSS-REFERENCE AND PRIORITY CLAIM TO RELATED APPLICATION
To the fullest extent permitted by law, the present Patent Cooperation Treaty application claims priority to and the full benefit of United States Provisional patent application entitled "ADHESIVE CROSS-LAMINATED THERMOPLASTIC NET-LIKE WEB AND METHOD OF FABRICATION THEREFOR", filed on March 2, 2004, and having assigned Serial No. 60/549,274.
TECHNICAL FIELD
The present invention relates generally to mesh fabric composites, and more specifically to an adhesive cross-laminated
thermoplastic net-like web and method of fabrication therefor.
The present invention is particularly advantageous for its provision of a cross-laminated thermoplastic net-like web modified to adhere to non-polyethylene substrates, foil, nylon, film, and/or foam, via thermal bonding, thus avoiding conventional methods of composite substrate fabrication that require additional, and often expensive, heat sealable films and/or adhesives to bond the multiple layers of same.
BACKGROUND OF THE INVENTION
Thermoplastic net-like webs, including cross-laminated webs formed from two or more layers of network structures having the same or different configurations, provide webs with high strength and tear resistance in multiple directions. Such webs are often utilized to reinforce selected materials, such as foils, foams, paper products, and the like.
In particular, manufacturers of home construction insulation often reinforce and strengthen polystyrene and urethane foams by adhering cross-laminated webs thereto. Similarly, some carpet pad manufacturers adhere mesh fabric to urethane foam via a thin urethane film to yield a reinforced and strengthened carpet pad product. Still other manufacturers of home construction products typically laminate polyethylene foam to cross-laminated webs via an extrusion coated layer of low- density-polyethylene (LDPE) . Foils are also typically adhered
to cross-laminated webs for purposes of supplying the foils with strength and durability. Although such foam-web or foil-web composites provide the requisite reinforced and/or strengthened home construction product, each such product disadvantageously requires the application of additional heat sealable films and/or adhesives to bond the selected foam or foil substrate to the cross-laminated web, thus imparting significant materials and manufacturing costs unto the manufacturer.
Therefore, it is readily apparent that there is a need for a cross-laminated thermoplastic net-like web modified to adhere, via simple thermal bonding processes, to foil, foam, nylon, film and/or other selected substrates, without the application of additional sealing films, adhesives, and/or the like, between the selected substrate and cross-laminated thermoplastic web.
BRIEF SUMMARY OF THE INVENTION
Briefly described, in a preferred embodiment, the present invention overcomes the above-mentioned disadvantages, and meets the recognized need for such an invention by providing an adhesive cross-laminated thermoplastic net-like web and method of fabrication therefor, wherein the present adhesive web comprises heat-activated resins blended therewith to facilitate adherence of the web to non-polyethylene substrates, foil, foam, nylon, film and/ox other selected substrates, thus avoiding conventional web composite manufacturing processes requiring the
application of additional sealing films, adhesives, and the like, between the selected substrate and cross-laminated thermoplastic web.
According to its major aspects and broadly stated, the present invention in its preferred form is an adhesive cross- laminated thermoplastic net-like web and method of fabrication therefor, comprising, in general, an ethyl methyl acrylate (EMA) resin, or, alternatively, an ethylene vinyl acetate (EVA) resin or ethylene methacrylic acid (EMAA) resin, blended with the machine direction layer (i.e., warp web or strands) of a cross- laminated thermoplastic net-like web so as to promote thermal bonding of same to non-polyethylene substrates, foil, foam, nylon, film and/or other selected substrates.
More specifically, the present invention is an adhesive cross-laminated thermoplastic net-like web and method of fabrication therefor, wherein the cross-laminated thermoplastic net-like web is manufactured by slitting or fibrillating two blown films, i.e., into a plurality of strands, each comprising low-density-polyethylene/high-density-polyethylene/low-density- polyethylene (LDPE/HDPE/LDPE) layers (i.e., layers of thermoplastic polymer) in preferably 15/70/15 ratios, respectively, and thereafter thermally bonding each slit or fibrillated film (i.e., the strands), one to the other, to form a mesh web or net-like fabric.
Specifically"," "in the manufacture of the cross-laminated web, a first film is slit or fibrillated in the machine direction (i.e., warp web), wherein a second film is slit or fibrillated in the cross machine direction (i.e., weft web). During the blending processes of the LDPE and HDPE thermoplastic polymers of the warp and weft webs, an ethyl methyl acrylate (EMA) resin, or, alternatively, an ethylene vinyl acetate (EVA) resin or ethylene methacrylic acid (EMAA) resin, is preferably blended with the warp web (i.e., machine direction film) only.
As such, during fabrication of a selected web-substrate composite, application of heat to the finished cross-laminated thermoplastic net-like web and selected substrate "activates" or "softens" the EMA resin (or EVA or EMAA resin) blended in the warp web layer of the cross-laminated thermoplastic net-like web, thus resulting in adherence of the cross-laminated thermoplastic net-like web to "the selected substrate (i.e., to the foil, foam, nylon, film and/or other selected substrate) .
Although the EMA resin (or EVA or EMAA resin) additive does not have to be present in the machine direction (MD) film only, it is especially advantageous to do so since it is the MD film side of the cross-laminated thermoplastic net-like web that is preferably placed and sealed against the selected substrate, whereas the cross-machine direction (CD) film of the cross- laminated thermoplastic net-like web preferably contacts the heated laminating roll, thus reducing the likelihood of the
cross-laminated thermoplastic net-like web sticking to the heated roll during heat sealing of the web to the selected substrate. However, it should be recognized that the resin may be placed in whichever film or web section that will ultimately be heat sealed to the selected laminate.
Accordingly, a feature and advantage of the present invention is the ability of the adhesive cross-laminated thermoplastic net-like web to adhere, via simple thermal bonding, to non-polyethylene substrates, foil, foam, nylon, film, and/or other selected substrates, without the application of additional sealing films, adhesives, and/or the like, between the selected substrate and cross-laminated thermoplastic web; thereby, significantly reducing materials and manufacturing costs of such web-reinforced substrate products.
Another feature and advantage of the present invention is its ability to maintain the original aesthetic qualities of the individual web and selected substrate following the thermal bonding between same simply by virtue of eliminating conventional application of additional films and/or adhesives therebetween.
Still another feature and advantage of the present invention is the ability of a manufacturer to manipulate the strength and resiliency of the web-substrate composite by varying the amount of EMA, EVA or EMAA resin blended with the
macnine direction film (i.e., warp web) of the cross-laminated thermoplastic net-like web, thus creating a customized web- substrate composite specifically designed for a selected application.
These and other features and advantages of the present invention will become more apparent to one skilled in the art from the following description and claims when read in light of the accompanying drawings .
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be better understood by reading the Detailed Description of the Preferred and Alternate Embodiments with reference to the accompanying drawing figures, in which like reference numerals denote similar structure and refer to like elements throughout, and in which:
FIG. 1 is a perspective view of a warp and weft web manufacturing line utilized to form the warp and weft webs of an adhesive cross-laminated thermoplastic net-like web according to a preferred embodiment of the present invention;
FIG. 2 is a perspective view of a transverse-stretch laminating line utilized to form an adhesive cross-laminated thermoplastic net-like web according to a preferred embodiment of the present invention; and,
FIG. 3 is a side view of an adhesive cross-laminated thermoplastic net-like web adhered to a foam substrate according to a preferred embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED AND SELECTED ALTERNATIVE EMBODIMENTS
To the fullest extent permitted by law, the present Patent Cooperation Treaty application claims priority to and the full benefit of United States Provisional patent application entitled "ADHESIVE CROSS-LAMINATED THERMOPLASTIC NET-LIKE WEB AND METHOD OF FABRICATION THEREFOR", filed on March 2, 20O4, and having assigned Serial No. 60/549,274.
In describing the preferred and selected alternate embodiments of the present invention, as illustrated in FIGS. 1- 3, specific terminology is employed for the sake of clarity. The present invention, however, is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish similar functions .
Preferably, the present invention contemplates in one of several embodiments an adhesive cross-laminated thermoplastic net-like web modified to adhere to foil/' foam, nylon, film
and/or other """selected substrates, wherein the cross-laminated thermoplastic net-like web preferably comprises an ethyl methyl acrylate (EMA) resin, or, alternatively an ethylene vinyl acetate (EVA) resin or ethylene methacrylic acid (EMAA) resin, blended with the machine direction layer (i.e., warp web) of the cross-laminated thermoplastic net-like web so as to promote thermal bonding of same to the selected substrate.
Briefly, and for explanatory purposes, a thermoplastic net- like web is preferably a net-like structure comprising a multiplicity of aligned thermoplastic elements or strands, wherein a first segment of thermoplastic elements or strands is aligned and laminated at approximately a 45-degree angle to approximately a 90-degree angle to a second segment of thermoplastic elements or strands, thereby collectively forming and defining a border for multiple void areas of the net-like non-woven structure. The border that defines the multiple void areas can be parallelogram-shaped, such as a square, rectangle or diamond, or, alternatively, ellipse-shaped, such as a circle or ellipse, depending upon the process of formation of the netlike web. Furthermore, the thermoplastic elements that define the border can be in the same plane or different planes, wherein thermoplastic elements in different planes can be laminated to each other. A preferred thermoplastic net-like web is a "cross- laminated thermoplastic net-like web" having a first uniaxially oriented thermoplastic film (i.e., warp web) laminated to a second uniaxially oriented thermoplastic film (i.e., weft web)
such that "the"""angle between the direction of orientation of the first and second films is approximately 45 degrees to approximately 90 for purposes of obtaining good strength and tear resistance properties in more than one direction. The orientation and/or formation of the network structure in the films can be completed either before the bonding operation, or, alternatively, during the bonding process.
Referring now to FIG. 1, illustrated therein is web manufacturing line 100, wherein web manufacturing line 100 is preferably utilized to manufacture warp and weft webs/films 200 and 250, respectively, for subsequent thermal bonding of same to form adhesive cross-laminated thermoplastic net-like web 400 of the present invention. Warp and weft webs 20O and 250, respectively, are preferably formed from film forming materials such as, for exemplary purposes only, thermoplastic synthetic polymers of polyolefin including, without limitation, low density polyethylene, linear low density polyethylene, polypropylene, high density polyethylene, random copolymers of ethylene and propylene and/or combinations thereof; polyesters; polyamides; and/or polyvinyl polymers including, without limitation, polyvinyl alcohol, polyvinyl chloride, polyvinyl acetate, polyvinylidene chloride and/or copolymeαrs of the monomers of therefor.
More specifically, however, the preferred materials for fabrication of warp and weft webs 200 and 250, respectively, are
polyesters" and ""polyolefin such as polypropylene , random copolymers of propylene and ethylene, and a combination of high- density polyethylene and low-density polyethylene. Additionally, the above-referenced thermoplastic synthetic polymers may also selectively comprise additives such as, for exemplary purposes only, stabilizers, plasticizers, dyes, pigments, anti-slip agents, and/or foaming materials for foamed films and the like.
Preferably, the present invention utilizes a three-layer coextruded film construction for formation of warp and weft webs/films 200 and 250, respectively, wherein the exterior two layers of the three-layer coextruded films are preferably composed of the same polymer, and wherein the interior layer is preferably composed of a different polymer. Alternatively, each of the three layers of the three-layer coextruded film construction could each be formed from any combination of polymers. The interior layer can occupy approximately 5% to approximately 95% of the overall thickness of the three-layer coextruded film, and more specifically, preferably composes approximately 50% to approximately 80% of the overall thickness of the three-layer coextruded film. The exterior two layers preferably compose approximately 20% to approximately 50% of the overall thickness of the three-layer coextruded film, and are preferably approximately equal in thickness. Co-extruded films are typically utilized for the manufacture of cross-laminated thermoplastic net-like webs, wherein one layer of film is cross-
laminated and bonded to a second layer of film, and wherein the exterior layers of the film comprise compatible and easily bondable thermoplastic materials such as, for exemplary purposes only, low-density polyethylene or linear low-density polyethylene.
Warp web 200 is preferably manufactured via web manufacturing line 100, wherein weft web 250 is also preferably manufactured in a substantially equivalent manner and process, with the exclusion of the EVA (or EMA or EMAA) resin additive, and the direction of slitting or fibrillation, as more fully described below. Hoppers 102 and 104 preferably comprise high density polyethylene (HDPE) and low density polyethylene (LDPE) , respectively, wherein hopper 102 preferably conveys the HDPE to main extruder 106, and wherein hopper 104 preferably conveys the LDPE to auxiliary extruder 108. Although coextrusion is the preferred method of forming webs 200 and 250, it is contemplated in an alternate embodiment that other suitable methods of forming webs 200 and 250 could be utilized, such as, for exemplary purposes only, casting, blowing and/or other web/film- forming methods .
Main extruder 106 and auxiliary extruder 108 preferably extrude the HDPE and LDPE, respectively, into blender 112 for subsequent formation of multi-layered LDPE/HDPE/LDPE warp web
200. During the blending processes of the HDPE and DPE thermoplastic polymers of warp web 200, an ethyl methyl acrylate
(EMA) resin, or alternatively an ethylene vinyl acetate (EVA) resin or ethylene methacrylic acid (EMAA) resin, supplied via hopper 110, is preferably blended in the warp web 200 (i.e., the machine direction film) only. As such, and as more fully described below, upon application of heat to the subsequently formed cross-laminated thermoplastic net-like web 400, the resin blended with warp web 200 is preferably "heat-activated," thereby facilitating web 400 to adhere more easily to non- polyethylene substrates, foil, nylon, film, and/or other selected substrates.
That is, available cross-laminated thermoplastic net-like webs sold by Atlanta Nisseki CLAF, Inc. under the designation of CLAF® (with product designations of CLAF S, CLAF SS, CLAF SSS, CLAF HS and CLAF MS) are typically produced with polyethylene blended with LDPE. Accordingly, substrates such as polystyrene foam will generally not adhere to such polyethylene-LDPE based thermoplastic webs without modification to the CLAF® fabric via addition of the EVA, EMA or EMAA resins or corona treatment. As such, an EMA resin is preferably added in the ratio of approximately 30% EMA to approximately 70% LDPE in production of warp web 200. Preferably, the EMA resin additive is an ethyl methyl acrylate copolymer sold by ExxonMobil® Chemical under the trade name OPTEMA TC 110; although, other suitable EMA resins could be utilized.
Alternatively,""'an EVA resin could be added in the ratio of approximately 50% EVA to approximately 50% LDPE in production of warp web 200, wherein the EVA resin additive is preferably an anhydride-modified ethylene vinyl acetate copolymer resin sold by DuPont® under the trade name BYNEL 3810; although, other suitable EVA resins could be utilized.
It is still further contemplated, in an alternate embodiment, that an EMAA resin could be added in the ratio of approximately 20% to approximately 40% EMAA to LDPE in production of warp web 200, wherein the EMAA resin additive is preferably an ethylene methacrylic acid copolymer resin sold by DuPont® under the trade name NUCREL 0903; although, other suitable EMAA resins could be utilized in contemplation of the acid content of the EMAA and the effect of same, if any, on extrusion equipment.
Although the above-referenced ratios of EMA, EVA or EMAA to LDPE are preferred for the production of warp web 200 and for effective web-to-substrate adherence, it should be recognized that other suitable ratios of EMA to LDPE, EVA to LDPE, or EMAA to LDPE could be utilized, resulting in calculable variations in adhesion per unit surface area.
Although the EMA resin (or EVA or EMAA resin) additive does not have to be present in the warp web 200 (i.e., machine direction (MD) film) only, it is especially advantageous to do
so since it is the MD film side of the subsequently formed cross-laminated thermoplastic net-like web/fabric 400 that is preferably placed and sealed against the selected substrate, whereas the weft web 250 (i.e., cross-machine direction (CD) film) of web 400 preferably contacts the heated calender or laminating rollers, thus reducing tine likelihood of cross- laminated thermoplastic net-like web 4O0 sticking to the heated calender rollers during heat sealing of web 400 to the selected substrate .
Preferably, warp web 200 is sli_t or fibrillated in the machine direction to provide a plurality of strands. Similarly, weft web 250 is also preferably slit orr fibrillated to provide a plurality of strands; however, slits formed in weft web 250 are preferably formed perpendicular to the slits formed in warp web 200 (i.e., in the cross machine direction), wherein the formation of slits on weft web 250 is preferably implemented via slitter 310, as best depicted in FIG. 2. Warp web 200 is preferably continuously or discontinuo "usly slit or fibrillated via film fibrillator 122 so as to permit subsequent formation of the plurality of void areas of thermoplastic net-like web 400.
It should be recognized that the net-like structure of web
200 and/or web 250 could also be formed via any other suitable slitting or fibrillating means or processes such as, for exemplary purposes only, forming on one side of warp web 200 and/or weft web 250 a plurality of parallel continuous main ribs
and a plurality of parallel discontinuous tie ribs on the opposite side of the respective film, and, thereafter, drawing web 200 and/or web 250 in one or two directions to open web 200 and/or web 250 into a network structure, or, alternatively, punching or stamping out material from web 200 and/or web 250 to form a pattern of holes therein, and thereafter stretching the webs to elongate the spaces between the pattern of holes . It is still further contemplated that the net-like structure of warp web 200 and/or weft web 250 could also be formed by extrusion with the webs being oriented by a stretching operation.
During the formation of adhesive cross-laminated thermoplastic net-like web 400, weft web 250 is preferably simultaneously being manufactured through web manufacturing line 100, and thereafter continuously fed through heat calender rollers 308 for lamination and heat bonding to pre-fabricated warp web 200. However, it should be recognized that weft web 250 could also be pre-fabricated prior to bonding with pre- fabricated warp web 200.
Although heat bonding of warp web 200 to weft web 250 is preferably conducted by heat calender rolls 308, it is contemplated in alternate embodiments that bonding of warp web 200 to weft web 250 could be accomplished via other suitable bonding means such as, for exemplary purposes only, by applying an adhesive between warp web 200 and weft web 250, and
thereafter passing warp web 200 and weft web 250 through a heating chamber and calender rolls to bond saπne, and/or by utilizing ultrasonic bonding, spot bonding and/or any other suitable bonding technique.
Following lamination and heat bonding of warp web 200 to weft web 250, the resulting adhesive crross-laminated thermoplastic net-like web 400 is preferably wound or collected via roller 312 for future application and adherence to a selected substrate.
Specifically, adhesive cross-laminated therιn.oplastic netlike web 400 with the added EMA (or EVA or EMAA) resin allows adhesive web 400 to be heat bonded to nom-polyethylene substrates, foils, foams, nylons, films, papers , and/or any other selected substrates, via heat-activating the EMA (or EVA or EMAA) resin, wherein such bonding functions to increase the strength and resiliency of the bonded substrate. As best illustrated in FIG. 3, adhesive cross-laminated thermoplastic net-like web 400 is shown preferably heat bonded to a substrate 30 to form web-substrate composite 10, wherein substrate 30 may comprise, without limitation, non-polyethylene substrates, foils, foams, nylons, films, papers, and/or any other selected substrates .
It should be recognized that a plurality of factors, such as the type or composition of thermoplastic utilized for
fabrication of the various web layers, the amount and type of
EMA, EVA or EMAA resins utilized, the desired composite production rate, the composite basis weight, process parameters such as the temperature of the calender rolls, the amount of pressure exerted on the films by the rolls, and the speed of the webs fed through the rolls, could all be varied to achieve a variety of desired and calculable results .
It should be further recognized that the present invention may be applied to woven fabric technology, wherein a selected resin may be combined with a plurality of warp strands, and wherein the resin-containing warps strands may subsequently be knitted or otherwise woven with a plurality of weft strands.
It is contemplated in an alternate embodiment that warp web 200 and weft web 250 could be fabricated via other known web fabricating methods other than through, or in addition to, web manufacturing line 100.
It is contemplated in another alternate embodiment that adhesive cross-laminated thermoplastic net-like web 400 could be manufactured via any other suitable manufacturing process other than through, or in addition to, transverse-stretch laminating line 300.
It is contemplated in yet another alternate embodiment that cross-laminated thermoplastic net-like web 400 could comprise
other" suitable resins" other than, or in addition to, EMA, EVA and/or EMAA resins.
It is contemplated in still yet another alternate embodiment that warp web 200 and weft web 250 could be formed from any suitable web/film forming materials.
It is contemplated in still a further alternate embodiment that weft web 250 of web 400 could be thermally bonded or otherwise adhered to a selected substrate due to the inherent
"openness" of weft web 250, thereby yielding a substrate-to-web
400-to-substrate composite.
It is contemplated in still yet a further alternate embodiment that web 400 could be thermally bonded or otherwise adhered to polyethylene substrates due to the polyethylene composition of web 400.
Having thus described exemplary embodiments of the present invention, it should be noted by those skilled in the art that the within disclosures are exemplary only, and that various other alternatives, adaptations, and modifications may be made within the scope of the present invention. Accordingly, the present invention is not limited to the specific embodiments illustrated herein, but is limited only by the following claims.