Shrink wrap material having reinforcing scrim and method for its manufacture

Information

  • Patent Grant
  • 6696120
  • Patent Number
    6,696,120
  • Date Filed
    Thursday, October 12, 2000
    23 years ago
  • Date Issued
    Tuesday, February 24, 2004
    20 years ago
Abstract
A shrink wrap material for protecting articles includes at least one non-woven fabric and a woven scrim defining apertures. A sufficient portion of the fibers from the non-woven fabric being forced into the apertures of the scrim such that the scrim reinforces and supports the non-woven fabric, thus increasing their strength. A shrinkable, stretchable film is intermittently bonded to at least one non-woven fabric. The material is used by placing the material around the article to be protected and then shrinking the film.
Description




TECHNICAL FIELD




This invention relates to a shrink wrap material for protecting objects during transport and storage which has a reinforcing scrim.




BACKGROUND OF THE INVENTION




Large articles, such as automobiles, machinery and boats must often be transported from the factory to the ultimate consumer on open trucks where they are exposed to the environment. Consumers expect that new automobiles, boats and machinery be in pristine condition and will not tolerate defects. As discussed in prior U.S. Pat. No. 5,491,017, damage may be caused by a number of factors including acid rain and hurled objects, such a small rocks and stones.




The wrap material disclosed in U.S. Pat. No. 5,491,017 includes a non-woven fabric intermittently bonded to a shrinkable and stretchable film that has a predetermined shrink response as heat is applied thereto. However, for some applications, a stronger wrap material is required. U.S. Pat. No. 5,712,008 discloses a wrap material similar to that disclosed in U.S. Pat. No. 5,491,017, except that a woven material is used instead of the non-woven fabric, thereby increasing the strength of the material. The woven material, however is not as soft as the non-woven fabric.




SUMMARY OF THE INVENTION




The present invention provides a multi-layer material that may be shrunk around articles to protect them during transport and storage. The material includes a shrinkable film and a non-woven material reinforced by a reinforcing scrim. Accordingly, due to the reinforcement provided by the scrim, the multi-layer material according to the present invention has increased strength and tear resistance as compared to other known materials, but retains the softness of such material. Accordingly, the multi-layer material of the present invention may be used where a stronger material is desired or required yet has the softness to protect the surface of the article.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a fragmentary cross-sectional view taken through the material of the present invention, with the edge of the material being pulled apart to disclose the various layers of the material;





FIG. 2

is an exploded view in perspective illustrating the material of the present invention;





FIG. 3

is an exploded view in perspective illustrating an alternative embodiment of the material of the present invention;





FIG. 4

is a schematic illustration of a preferred method of manufacturing the material shown in

FIGS. 1 and 2

;





FIG. 5

is a schematic illustration of a preferred method of manufacturing the material shown in

FIG. 3

;





FIG. 6

is a schematic illustration of a second preferred method of manufacturing the material shown in

FIGS. 1 and 2

;





FIG. 7

is a schematic illustration of a second preferred method of manufacturing the material shown in

FIG. 3

; and





FIG. 8

is a perspective view showing the material of the present invention formed into a protective article.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT




Referring now to

FIGS. 1 and 2

, the multi-layer material


10


of the present invention includes a first layer


12


of a shrinkable film, preferably a shrinkable, stretchable film, such as a film available from Wright Plastics Corporation, Prattville, Ala. and sold as film TS-5, or a film sold as film C-40 by Crayex Corporation, Piqua, Ohio. The multi-layer material


10


includes a composite layer generally indicated by the numeral


14


. The first layer


12


and composite layer


14


are secured to each other by intermittent bonds. As disclosed in the above-mentioned U.S. Pat. No. 5,491,017, the material


10


is used by arranging the material


10


around the article to be protected with the second layer


14


resting on the surface of the article and supporting the film or first layer


12


away from the surface of the article. This may be accomplished by forming the material into a bag (such as by sewing panels of the material


10


together or by joining panels of the material


10


by other appropriate methods, such as by ultrasonic welding or RF sealing) which fits over the article being protected. Heat is then applied to the material to shrink the film. Since the first film layer


12


shrinks and the second layer


14


does not shrink to any appreciable extent, the regions of the second layer


14


between the intermittent bonds separate or release from the film and then gather up to form cushions.




With a continued reference to

FIGS. 1 and 2

, the second layer


14


includes a first fibrous web


16


and a second fibrous web


18


on opposite sides of a scrim


20


. The fibrous webs


16


and


18


may be commercially available non-woven fabrics, such as the hydro-entangled non-woven fabric Sontara® available from DuPont Co., or any other non-woven fabric made from natural or man-made fibers, or combinations thereof, such as polyester, nylon 6,6 or a combination of nylon and polyester fibers. As will be described hereinafter with respect to

FIG. 4

, the fibrous webs


16


and


18


may be formed by depositing fibers directly on the scrim instead of being first formed into a non-woven fabric. The scrim


20


is generally woven from threads


22


made out of, by way of non-limiting example, PET, PP, or HDPE, having an average diameter of between about {fraction (1/64)}″ to about ⅛″. The threads


22


are woven into a scrim


20


generally having 3 threads in each direction per square inch (a 3,3 weave) to 10 threads in each direction per square inch (a 10,10 weave) to form apertures


24


. As will be discussed hereinafter, the scrim


20


is disposed between the fibrous webs


16


,


18


which are pressed against the scrim


20


during the manufacturing process to force some of the fibers of each of fibrous the webs


16


and


18


into the apertures


24


of the scrim


20


, thereby securing the fibrous webs


16


and


18


to the scrim


20


. Accordingly, the scrim


20


supports and reinforces the fibrous webs


16


and


18


. The scrim


20


may also be formed from an adhesive thermoplastic or elastomeric material if so desired, such as hot melt or pressure sensitive adhesives, by way of non-limiting example.




As discussed above, the second layer


14


consisting of the fibrous webs


16


and


18


, which are supported and reinforced by the scrim


20


, are secured to the first layer


12


by intermittent bonds formed between the web


18


and the first layer


12


. The intermittent bonds securing the first layer


12


to the web


18


of the second layer


14


are formed by applying an adhesive to the raised portions


19


of the surface of the fibrous web


18


, as more fully described in the aforementioned U.S. Pat. No. 5,491,017. Alternatively, the adhesive may be applied in a repeating pattern by a conventional gravure roll to either the surface of the fibrous web


18


or to the first layer


12


. The adhesive is preferably a pressure-responsive hot melt adhesive of the block copolymer family such as, but not limited to, S-I-S (styrene-isoprene-styrene), S-E-S (styrene-ethylene-styrene) or similar adhesive. Such adhesives are available from ATO Corp. of Findlay, Ohio and H. B. Fuller Corp. of Minneapolis, Minn.




The presence of the reinforcing scrim


20


increases the strength and tear resistance of the material


10


, making it possible to protect articles in environments where the prior art materials did not have sufficient strength. As discussed in U.S. Pat. No. 5,491,017 and illustrated in

FIG. 8

, the material


10


may be formed into a protective article


64


such as a bag (by cutting the material


10


into panels and joining the panels by sewing, heat sealing or any other appropriate way). By use of the material of the present invention, bags


10


having more complex geometries which would otherwise compromise bag strength, may be used compared to bags made with prior art materials since shrinking the bags of the present material will not easily rupture.




As also disclosed in U.S. Pat. No. 5,491,017, the bag is placed over the object to be protected and then shrunk by applying heat thereto to shrink the film. Accordingly, upon shrinking, the bag closely conforms to the contours of the product such that the scrim


20


is held away from the surface by the non-woven fabric, so that the surface of the article is not damaged while the advantage of the extra strength of the scrim is maintained. After shrinking the film or first layer


12


, the scrim


20


substantially adapts to the shape of the surface of the article being protected, but remains elastic after shrinking until the material


10


is removed from the object.




Referring to

FIG. 3

, there is shown an alternative embodiment of the material


10


which includes a first layer of film


12


and a second layer


14


which includes a fibrous web


16


and a scrim


20


. According to this embodiment, the second fibrous web which had been disposed between the film


12


and scrim


20


has been eliminated.




One method of manufacturing the material


10


of the present invention will now be described with reference to FIG.


4


. Non-woven fabric is commonly supplied in rolls, such as the rolls


26


and


28


which are supported above an endless conveyor belt generally indicated by the numeral


30


. The scrim


20


is also commonly supplied in rolls, such as the roll


32


supported above the conveyor


30


between the rolls


26


and


28


of the non-woven fabric.




Non-woven fabric is pulled from the roll


26


and held against the conveyor belt


30


(which moves in the direction indicated by the arrow A) by roller


34


. As the conveyor belt


30


transports the non-woven fabric from roll


26


, scrim


20


is pulled from the roll


32


and held against the upper surface of the non-woven fabric from the roll


26


by a roller


36


. As the non-woven fabric from roll


26


and the scrim from roll


32


are transported further, non-woven fabric is pulled from the roll


28


and held against the side of the scrim by roller


38


.




The conveyor


30


then transports the two layers of non-woven fabric between which the scrim


20


is disposed through a set of compression rollers


40


. The compression rollers


40


are adjusted to apply a compression force which presses some of the fibers on the surfaces of the non-woven fabrics into the apertures of the scrim


20


sufficient that the layers of non-woven fabric are integrated with the scrim


20


so that the scrim supports and reinforces the non-woven fabric. It is important that during the laminating/gluing process the low compression forces applied to the non-woven are sufficiently low to effect lamination which does not substantially compress the non-woven fabric to the scrim


20


but rather allows the formation of cushions or raised portions. The material thus formed is then transferred to a gluing station


42


, in which adhesive from receptacle


44


is applied via roller


46


to the raised portions of the upper surface of the non-woven fabric on the top of the scrim, such that the adhesive is applied intermittently only on the raised portions of the non-woven fabric as described in U.S. Pat. No. 5,491,017.




The film


12


is pulled from a roll


48


supported over the conveyor belt


30


, which transfers the product to a bonding station generally indicated at


50


. The bonding station provides a light touching pressure sufficient to cause the adhesive to bond in the areas where the adhesive is been applied and thereby forms the intermittent bonds between the first film layer


12


and the second layer


14


which includes the scrim and the non-woven fabrics. As discussed above, the adhesive is a hot melt, pressure sensitive adhesive that requires only “touching pressure” to bond.




It should be appreciated that instead of applying the adhesive only to the raised portions of the non-woven fabric facing the film, the adhesive may be applied in a repeating pattern to either the film or the non-woven fabric surface by, for example, a contoured gravure roll (not shown) to achieve the intermittent bonding. The material


10


after bonding is then rolled onto a take up roll


52


.




Referring to

FIG. 5

, a method of manufacturing the material


10


as illustrated in

FIG. 3

will now be described. Again, the non-woven fabric is commonly supplied on a roll, such as roll


26


which is supported above an endless conveyor belt generally indicated by the numeral


30


. The scrim


20


is also commonly supplied in rolls, such as the roll


32


supported above the conveyor


30


before roll


26


.




Non-woven fabric is pulled from the roll


26


and held against the conveyor belt


30


(which moves in the direction indicated by the arrow A) by roller


34


. As the conveyor belt


30


transports the non-woven fabric from roll


26


, scrim


20


is pulled from the roll


32


and held against the upper surface of the non-woven fabric from the roll


26


by a roller


36


.




The conveyor


30


then transports the layer of non-woven fabric from roll


26


and scrim


20


through a set of compression rollers


40


. The compression rollers


40


are adjusted to apply a compression force which presses some of the fibers on the surfaces of the non-woven fabric into the apertures of the scrim


20


sufficient that the layer of non-woven fabric is integrated with the scrim


20


so that the scrim supports and reinforces the non-woven fabric. It is important that during the laminating/gluing process the low compression forces applied to the non-woven are sufficiently low to effect lamination which does not substantially compress the non-woven fabric to the scrim


20


but rather allows the formation of cushions or raised portions. The material thus formed is then transferred to a gluing station


42


, in which adhesive from receptacle


44


is applied via roller


46


to the raised portions of the upper surface of the non-woven fabric extending through the scrim, such that the adhesive is applied intermittently only on the raised portions of the non-woven fabric.




The film


12


is pulled from a roll


48


supported over the conveyor belt


30


, which transfers the product to a bonding station generally indicated at


50


. The bonding station provides a light touching pressure sufficient to cause the adhesive to bond in the areas where the adhesive has been applied and thereby forms the intermittent bonds between the first film layer


12


and the second layer


14


which includes the scrim and the non-woven fabric. As discussed above, the adhesive is preferably a hot melt, pressure sensitive adhesive that requires only “touching pressure” to bond.




It should be appreciated that instead of applying the adhesive only to the raised portions of the non-woven fabric, the adhesive may be applied in a repeating pattern to either the film or the non-woven fabric surface by, for example, a contoured gravure roll (not shown) to achieve the intermittent bonding. The material


10


after bonding is then generally rolled onto a take up roll


52


.




Referring now to

FIG. 6

of the drawings, a second preferred method of manufacturing the material


10


will be described. A first mass of staple fibers generally indicated at


54


(staple fibers are fibers cut to a predetermined length) is deposited uniformly on the conveyor belt


30


from a hopper/carder


56


supported over the conveyor belt


30


and extending across the width of the conveyor belt


30


. The fibers may be any of the fibers discussed above, all of which are readily commercially available, or mixtures of fibers. The fibrous mass


54


is then transferred in the direction of the arrow A, and scrim


20


is pulled from the roll


32


and positioned against the fibrous mass


54


. A second fibrous mass indicated at


58


is provided onto the scrim


20


from a hopper/carder


60


supported over the conveyor belt


30


. The hopper/carder


60


is substantially identical to the hopper/carder


56


, and the fibers comprising the fibrous mass


58


may be substantially the same or different from the fibers comprising the fibrous mass


54


. The fibers stored within the hopper/carders


56


,


60


are preferably mixed with a powder adhesive to bind the fibers into a mat after being deposited on the conveyor belt


30


.




The conveyor belt


30


then transports the fibrous mass


54


and the scrim


20


through a set of compression rollers


40


. The compression rollers


40


are set to sufficiently compact the fibrous mass


54


to force the fibers to entangle with one another and to force some of the fibers into the apertures defined by the scrim


20


. Accordingly, the scrim


20


supports and reinforces the fibers of the fibrous mass


54


which have been sufficiently compressed to form a web of non-woven fabric. As discussed above, the film


12


is intermittently bonded to the fibers, and the completed wrap material


10


may then rolled on the take up roll


52


and stored for use.




Referring to

FIG. 7

, yet another method of manufacturing the material


10


of the present invention will now be described. A first mass of staple fibers generally indicated at


54


(staple fibers are fibers cut to a predetermined length) is deposited uniformly on the conveyor belt


30


from a hopper/carder


56


supported over the conveyor belt


30


and extending across the width of the conveyor belt


30


. The fibrous mass


54


is then transferred in the direction of the arrow A, and scrim


20


is pulled from the roll


32


and positioned against the fibrous mass


54


. The fibers stored within the hopper


56


are preferably mixed with a powder adhesive to bind the fibers into a mat after being deposited on the conveyor belt


30


. The conveyor belt


30


then transports the fibrous masses


54


,


58


and the scrim


20


through a set of compression rollers


40


. The compression rollers


40


are set to sufficiently compact the fibrous masses


54


,


58


to force the fibers to entangle with one another and form a unitary fibrous structure, and also to force some of the fibers from each of the fibrous masses


54


,


58


into the apertures defined by the scrim


20


and thus form a unitary fibrous structure. Accordingly, the scrim


20


supports and reinforces the fibers of the fibrous mass


54


and


58


, which have had their fibers sufficiently entangled by the compression rollers


40


to form a web or non-woven fabric. As discussed above, the film


12


is intermittently boned to the fibers, and the completed wrap material


10


may then rolled on the take up roll


52


and stored for use.




While it will be apparent that the preferred embodiments of the invention disclosed are well calculated to fulfill the objects stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the spirit thereof.



Claims
  • 1. Material for protecting articles comprising a heat shrinkable film first layer having a predetermined shrink response in response to heat applied thereto, and a composite second layer including a flexible scrim defining apertures and, first and second webs of fiber disposed on opposite sides of said flexible scrim such that said webs of fiber are entangled through the apertures of said scrim, said scrim remaining elastic after said material is heat shrunk, said second layer being secured to said film first layer via intermittent bonds.
  • 2. Material as claimed in claim 1, wherein said webs of fiber are in the form of non-woven fabrics.
  • 3. Material as claimed in claim 2, wherein said fibers of said non-woven fabrics are pressed into the apertures of the scrim.
  • 4. Material as claimed in claim 1, wherein said, webs of fiber are hydro-entangled with said scrim, wherein said scrim supports said fibers and resists pulling of said fibers away from one another.
  • 5. Material as claimed in claim 1, wherein multiple pieces of the material for protecting articles are joined together to form a protective article.
  • 6. Material as claimed in claim 1 wherein said intermittent bonds occurring between the first and second layers are adhesive bonds.
  • 7. Material as claimed in claim 6 wherein said adhesive bonds are hot melt adhesive bonds.
  • 8. Material as claimed in claim 1 wherein said first web of fibers include raised portions to which an adhesive is applied to form the intermittent bonds with said first film layer.
  • 9. Material for protecting the surface of articles against damage comprising a shrinkable film first layer and a second composite layer including;a) a first fibrous web which is intermittently bonded to said film first layer; b) an elastic scrim including apertures, said scrim being disposed along said first fibrous web opposite said film first layer; and c) a second fibrous web disposed along said elastic scrim opposite said first fibrous web, wherein said first and second fibrous webs are entangled with said scrim through said apertures.
  • 10. Material as claimed in claim 9, wherein said shrinkable film first layer has a predetermined shrink response in response to heat applied thereto.
  • 11. Material as claimed in claim 9, wherein said fibrous webs are in the form of non-woven fabrics.
  • 12. Material as claimed in claim 9, wherein said webs of fiber are hydro-entangled with said scrim, wherein said scrim supports said fibers and resists pulling of said fibers away from one another.
  • 13. Material as claimed in claim 9, wherein said intermittent bonds occurring between the first and second layers as adhesive bonds.
  • 14. Material as claimed in claim 9, wherein said adhesive bonds are hot melt adhesive bonds.
  • 15. Material as claimed in claim 9, wherein said first web of fibers include raised portions to which adhesive is applied to form the intermittent bonds with said first layer.
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