WO1991000831A1

WO1991000831A1 - Slip pallet

Info

Publication number: WO1991000831A1
Application number: PCT/US1990/003969
Authority: WO
Inventors: John A. Hansen; Bobby L. Mornin; Paul H. Lefevre
Original assignee: Adolph Coors Company
Priority date: 1989-07-12
Filing date: 1990-07-11
Publication date: 1991-01-24
Also published as: AU6058490A

Abstract

A slip pallet (10) constructed of material comprising both once-recycled and multiply-recycled polyethylene terephthalate, and comprising a four-sided sheet having a central portion (12) and at least one edge portion lip (14) which angles laterally upwardly from the central portion (12) along the entire length thereof. Preferably, from about 51 % to about 95 % of the polyethylene terephthalate is multiply-recycled, with the remainder of the polyethylene terephthalate being once-recycled.

Description

SLIP PALLET

Background of the Invention This invention relates to slip pallets upon which containerized goods can be stacked, and in particular to slip pallets constructed of material comprising both once-recycled and multiply-recycled polyethylene terephthalate. slip pallet is a relatively thin sheet of square or rectangular material upon which containerized goods such as boxed, canned food or beverages, for example, are stacked for shipment and storage. Stacks of goods can be multi-tiered, with each tier separated by a slip pallet. The pallet itself characteristically has at least one lip along one edge thereof to be ultimately disposed laterally from the vertical border of the stacked goods. The lip is formed by bending of the pallet near its edge and angles upwardly along the entire length thereof from the remainder of the pallet. These lips can be formed along one, two, thr e or four edges of the pallet. Conventional forklift vehicles provided with a combination grabber member and platen member first engage a lip and then pull the slip pallet and its supported goods onto the platen for subsequent delivery to another site.

Slip pallets traditionally have been constructed of a paper product such as heavy cardboard or of a 2 -

relatively thick plastic such as polypropylene. Paper construction can economically provide initial strength and rigidity, but can lose practicality especially in a damp environment. Present plastic construction such as

05 that employing polypropylene provides durability in most environments, but requires the use of a relatively large quantity of material in order to attain required strength and rigidity.

Virgin polyethylene terephthalate (PET) is widely

10 used in the food and beverage industries for packaging consumable products. Current regulations prohibit reuse of PET for such packaging, resulting in an extremely large amount of non-biodegradable, used PET being produced. A portion of this used PET is

15 presently being reclaimed by recyclers who extrude the used PET generally into particles such as pellets for a subsequent single reuse in producing another product by extrusion. Because PET is a polyester resin, however, it could be concluded that more than one recycling

20 operation will render the PET unusable because of breakdown of the polyester chain. Therefore, after one recycling, the now twice-used PET is discarded and can thereby produce an untoward environmental impact.

We have now discovered, however, that a material

25 comprising multiply-recycled PET and once-recycled PET can be employed in the construction of slip pallets, and that multiply-recycled PET can be the major constituent of the material used to construct a slip pallet having a structural integrity which exhibits

30 full functionality. Accordingly, it is a primary object of the present invention to provide a slip pallet exhibiting utility in most environments, yet be constructed with a relatively minimal amount of materials Yet another object of the present invention

35 is to provide a slip pallet constructed totally of recycled PET. A further object of the present invention is to provide a slip pallet wherein the major portion of its construction is multiply-recycled PET, and the minor portion thereof is once-recycled PET. These and other objects of the present invention will become apparent throughout the description which now follows.

Summary of the Invention The present invention is a slip pallet constructed of material comprising both once-recycled and multiply-recycled polyethylene terephthalate (PET) , and comprising a four-sided sheet having a central portion and at least one edge portion lip which angles laterally upwardly from the central portion along the entire length thereof. Preferably, from about 51% to about 95%, and, most preferably, from about 85% to about 95%, of the PET employed is multiply-recycled, with the remainder of the PET having been once-recycled. Constructing the slip pallet with PET yields a pallet whose durability equals that exr..bited by other plastics such as polypropylene, yet wh..^~e thickness, and therefore quantity of raw material used, can be less than about 50% by volume of such other plastic products. Additionally, because the source of PET is found in previously-used, recycled product, including primarily multiply-recycled, previously-used product, both the economic and environmental impacts are significantly reduced since most of the material is recycled more than once rather than beirg discarded after a single recycling operation.

Brief Description of the Drawinqs An illustrative and presently preferred embodiment of the invention is shown in the accompanying drawing figure which is a perspective view of a slip pallet. Detailed Description of a Preferred Embodiment Referring to the drawing figure, a slip pallet 10 constructed of both once-recycled and multiply-recycled polyethylene terephthalate (PET) is illustrated. The pallet 10 is a four-sided extruded sheet having a central portion 12 upon which containerized goods can be placed, and four edge portion lips 14 which angle laterally upwardly along their entire respective lengths from the central portion 12. The upward angle of the lips 14 is preferably between about 15° and about 60°. A pallet 10 must have at least one lip 14, and can have two, three or four lips 14 as needed or desired for particular applications. The lips 14 are conventionally formed by bending, and can be so formed by employing standard cold-bending apparatus to thereby provide the upward angle to the lips 14. Depending upon the thickness of the pallet 10, the lips 14 can bend further upwardly when pressure is applied thereto as would be found in juxtaposed pallets 10 bearing stacked goods. Upon release of such pressure, the lips 14 return to their initially-angled position. Respective adjacent ends of adjacent lips 14 can be provided with respective diagonal cuts 18 to thereby provide respective diagonal configurations and prevent interference from each other when bent upwardly. As desired, the top surface of the pallet 10 can be provided with a surface finish having a coefficient of friction .greater than that of the under surface. This slippage-retardant characteristic can be accomplished, for example, by merely conventionally abrading the top surface or by providing appropriately-finished rollers in commonly-employed sheet extrusion apparatus. It is to be noted that the slip pallet 10 can also function as a divider sheet if positioned upside-down and disposed on the top of a stack of goods upon which another stack of goods residing on a pallet 10 is placed.

In the embodiment here shown, the thickness of the pallet 10 is about 0.025 inch. It has been determined that rigidity considerations determine the operable range of PET-construσted pallet thickness. Thus, while adequate goods-carrying strength is found in a pallet less than about 0.010 inch thick, such a pallet does not possess adequate rigidity to have pallet utility. Conversely, a thickness greater than about 0.035 inch results in a stiffness which prohibits bendability of the lips 14 during pallet use. A preferred thickness is between about 0.015 inch and about 0.030 inch. The pallet 10 here illustrated is constructed totally of once-recycled and multiply-recycled PET extruded in a conventional manner to the desired thickness. Preferably, it is primarily constructed of multiply-recycled PET along with a smaller portion of once-recycled PET. Thus, from about 51% to about 95%, and most preferably from about 85% to about 95%, of the PET is multiply-recycled, and from about 5% to about 49%, and most preferably from about 5% to about 15%, of the PET is once-recycled to thereby produce a slip pallet 10 whose structural integrity provides required utility. While it is preferred that the pallet be totally constructed of once-recycled and multiply-recycled PET, it is to be understood that other compatible constituents as would be recognized by a person with ordinary skill in the art can be included in material formulations employed for extrusion. In addition to providing an economic benefit, this use of multiply-recycled PET contributes toward a positive environmental impact since discard magnitude is significantly reduced. Because slip pallets usually are returned to the provider thereof after use and generally are not satisfactory for reuse because of deformation or the like, such returned pallets constructed according to the present invention provide an excellent source of multiply-recycled PET. These returned pallets can be ground, and the particles so produced can be mixed with once-recycled PET particles to form a substantially homogeneous mixture of material which can be conventionally re-extruded into new slip pallets.

Thus, as an example, if 10% of once-recycled PET is combined with 90% multiply-recycled PET derived from previously-used pallets for the construction of a new pallet, a given unit of PET would be used ten times. As earlier noted, the use of multiply-recycled PET as the primary constituent in the construction of a slip pallet effectively achieves a structural integrity which exhibits full functionality when only a relatively small amount of once-recycled PET is included. Not only does this novel slip pallet exhibit integrity not expected from multiple recycling procedures, but it also provides a pallet requiring less material, and therefore having less volume as well as less weight, than many other constructions with comparable utility.

While an illustrative and presently preferred embodiment of the invention has been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed and that the appended claims are intended to be construed to include such variations except insofar as limited by the prior art.

Claims

WHAT IS CLAIMED IS:

1. A slip pallet constructed of material comprising both once-recycled and multiply-recycled polyethylene terephthalate and comprising a four-sided sheet having a central portion and at least one edge portion lip which angles laterally upwardly from the central portion along the entire length thereof, with the proviso that at least about 5% of the polyethylene terephthalate is once-recycled.

2. A slip pallet as claimed in claim 1 wherein at least two adjacent edge portion lips angle laterally upwardly from the central portion.

3. A slip pallet as claimed in claim 2 wh rein respective adjacent ends of adjacent lips have respective diagonal configurations.

4. A slip pallet as claimed in claim 1 wherein the thickness thereof is :rom about 0.010 inch to about 0.035 inch.

5. A slip pallet as claimed in claim 4 wherein the thickness thereof is from about 0.015 inch to about 0.030 inch.

6. A slip pallet as claimed in claim 1 wherein from about 51% to about 95% of the polyethylene terephthalate is multiply-recycled and the remainder thereof is once-recycled.

7. A slip pallet as claimed in claim 6 wherein from about 85% to about 95% of the polyethylene terephthalate is multiply-recycled and the remainder thereof is once-recycled.

8. A slip pallet as claimed in claim 1 wherein the top surface thereof has a coefficient of friction greater than that of the under surface.

9. A slip pallet constructed of material comprising from about 51% to about 95% multiply-recycled polyethylene terephthalate and about 5% to about 49% once-recycled polyethylene terephthalate, and comprising a four-sided sheet of from about 0.010 inch to about 0.035 inch thick having a central portion and at least one edge portion lip which angles laterally upwardly from the central portion along the entire length thereof.

10. A slip pallet as claimed in claim 9 constructed of material comprising from about 85% to about 95% multiply-recycled polyethylene terephthalate and about 5% to about 15% once-recycled polyethylene terephthalate.

11. A slip pallet as claimed in claim 10 wherein the thickness thereof is from about 0.015 inch to about 0.030 inch.

12. A slip pallet as claimed in claim 11 wherein the top surface thereof has a coefficient of friction greater than that of the under surface.

13. A method for manufacturing a slip pallet, said method comprising: a) mixing material comprising from about 51% to about 95% multiply-recycled polyethylene terephthalate particles and about 5% to about 49% once-recycled polyethylene terephthalate particles to form a substantially homogeneous mixture; b) extruding the mixture of (a) into a four-sided sheet; and c) bending at least one edge of the extruded sheet upwardly to thereby form a sheet having a central portion and at least one edge portion lip which angles laterally upwardly from the central portion along the entire length thereof.

14. A method as claimed in claim 13 wherein the material comprises from about 85% to about 95% multiply-recycled polyethylene terephthalate particles and from about 5% to about 15% once-recycled polyethylene terephthalate particles are mixed.

15. A method as claimed in claim 14 wherein the mixture is extruded to a thickness of from about 0.10 to about 0.035 inch.

16. A method as claimed in claim 15 wherein the mixture is extruded to a thickness of from about 0.15 to about 0.030 inch.

1". A method as claimed in claim 16 wherein at least two adjacent edges of the extruded sheet are bent upwardly.

18. A method as claimed in claim 17 wherein respective ends of ac cent upwardly-bent edges are cut diagonally.