Surface Protection Material

Abstract

A protector sheet material serving as packing material for fine furniture and its combination with the furniture and a surrounding contacting container in such manner as to inhibit marking or buffing of the furniture in shipment. The protector sheet material has a foam surface for contacting the furniture and a paper backing for contacting the container in such manner that slippage in shipment occurs preferentially between the container and paper backing.

Parent Case Text

This application is a streamline continuation of application Ser. No. 837,563, filed June 30, 1969 and now abandoned.

Description

My present invention relates to sheet protector material adapted to overlie and to separate confined high finish surfaces of furniture and the like from supporting surrounding packaging containers, for example.

The invention has for a principal object to provide protector material which covers furniture surfaces or the like and which is non-slippable relative to such surfaces but is readily slippable relative to the inner surface of the supporting container.

An important object of the present invention is to provide the protector material so that it is of sufficient strength, flexibility and resiliency that it may be readily drawn around or passed about an edge or corner of a desk, table or the like to protect the same in shipment against surface buffing or abrasion which sometimes occurs due to relative motion between the container and the shipped articles.

A particular object of the invention is to provide a protector material having a large slip differential between its opposed surfaces. Slip differential is a measure of the tendencies of the opposed protector surfaces to slide on a surface of common characteristics and is conveniently expressed in degrees as noted hereinafter. For the purposes of this invention one surface of the protector material is provided to slide or slip readily on most surfaces such as paper, wood, metal and the like while the other surface is selected to have a large coefficient of friction relative to most surfaces.

Further and other objects and features of the invention will be more fully understood from the following detailed description and accompanying drawings wherein:

FIG. 1 is a perspective view of the protector material with one ply turned back to conveniently illustrate the underlying ply and a useful adhesive bonding arrangement of the plies;

FIG. 2 is a view of the protector material in usual functional position interposed between a carton interior and a surface to be protected;

FIG. 3 is a schematic view in side elevation of equipment useful in the production of the protector material;

FIG. 4 is a schematic view of apparatus useful in determining the slip characteristics of various materials.

Referring to the drawings and particularly initially to FIG. 1, the numeral 1 generally indicates the sheet protector material. The protector 1 includes a ply 2 of a soft, flexible, compressible foam; this foam ply, I have found, may suitably be of a wide variety of sponge-like materials including particularly ether and ester types of polyurethanes. Such products are commercially available in convenient thicknesses and densities for my purpose and no premium cost is involved in their supply. The thickness of the ply 2, I have found, may usefully be in the range of one-sixteenth to one-fourth inch and should be such that small dust or grit particles may be encompassed within its pores or interstices to thereby inhibit any "sandpaper type" action on surfaces to which the foam may be affixed. Additionally, I have found that the foams mentioned do not tend to mark or buff the fine polished wood surfaces common to television consoles, tables, desks and the like. The relatively high coefficient of friction or high slide angle, as noted more particularly hereinafter, is a further major factor in preventing marking or buffing of fine surfaces. The term buffing is used herein and the appended claims to indicate a polishing type of action wherein high gloss is imparted to a portion of the surface area of the material being protected by relative movement of the protector material.

The numeral 3 designates a paper backing for the foam ply 2. This paper backing should be strong, smooth on the outside exposed face, flexible and such that it has a relatively low coefficient of friction, that is, a tendency to slip or slide readily when in contact with other papers, cardboard, boxboard, wood, metal or the like. Kraft paper in the basis weight range of about 12 pounds to about 100 pounds is a useful material for the shipment of common articles such as chairs, pianos and the like, but a good generally useful product may have a kraft paper ply 3 of about 40 pounds per ream (24.times.36 inches .times.500 sheets). Tissue paper having a ream weight of 16 pounds or glassine may serve the purpose in many instances. Preferably, the ply 3 has a degree of stretchability to permit shock absorption particularly when the protector material is applied about sharp edges of an article in transit.

The numeral 4 indicates spaced adhesive dots which function to retain the paper ply 3 on the foam 2. Starch type adhesives are quite suitable as are the synthetic latices (acrylics, butadiene-styrene, etc.). Spot bonding of the piles 2 and 3 is preferred as stiffening of the product by the adhesive may be avoided and yet sufficient bond strength is attained to provide for a tough protector sheet. Importantly, the bond should be sufficiently strong to provide that shear forces transmitted in the general plane of the protector sheet by the paper ply 3 to the foam ply 2 do not cause ply separation.

The protector sheet is producible on a production basis with simple mechanical equipment illustrated in FIG. 3. As indicated in the drawing, a roll 5 of kraft paper (40 lb. basis weight) is directed over a relief glue printing roll 6 and into contact with a polyurethane foam sheet passing from roll 8. Adhesive 9 is applied by applicator roll 10 revolving in pot 11 to the periphery of the relief printing roll 6. The paper ply 3 and foam ply 2 are combined on the periphery of roll 12 and directed over guide roll 13 to lead-in roll 14 and windup roll 15 rotating in the directions indicated by the arrows. The method of protector sheet formation or production forms no part of the present invention and any convenient method may be employed for the purpose. The roll 15 may, of course, be suitably fashioned by cutting, trimming and the like to provide lengths of protector sheet 1.

A generally suitable protector sheet product for the shipment of household furniture, for example, may have the following characteristics: a polyether foam of open celled construction at a thickness of about three-sixteenths inch adhered to a kraft paper of about 40 pounds basis weight (24.times.36 inches .times.500 sheets) by polyvinyl acetate adhesive disposed in small spaced adhesive dots.

As illustrated in FIG. 2, the table 16 has applied to its upper surface, indicated generally at 17, a protector sheet 1 of FIG. 1 and which sheet may extend over the whole upper table surface and be drawn around the edges 18. The protector sheet is drawn taut but no particular stress need be applied, it being satisfactory if the foam 2 simply lies in face to face contact with surface 17. The protector sheet may be held in position by virtue of its own tension or by tape (not shown), for example, the tape contacting the protector sheet and the table on its underside.

When ready for transit, as illustrated in FIG. 2, the ply 2, which is of greater thickness than the ply 3, will contact the interior surface 21 of a shipping container, frequently a corrugated liner. Normally, when employing usual wadding sheets or the like between the surface 21 and the article packaged, relative movement of the container and article, due to sudden shock loads, container movement and the like, may result in slippage of the wadding on the article, causing surface scratches, marks and the like. In the present instance (FIG. 2) the slippage between the article and foam ply 2 is substantially eliminated as the foam does not readily slip on fine smooth surfaces, and such relative movement as may occur takes place between the ply 3 and the container interior surface 21, preventing marking of the article. In the course of any such movement the paper-foam material may be subjected to a shear action which is resisted by the combined effect of the adhering adhesive 9 and the supplementary paper-foam contact.

Suitability of materials for either the ply 2 or the ply 3 may be readily determined by use of the simple inclined plane of FIG. 4. As shown therein, a base 23 has pivoted thereto at 24 an angularly extending arm 25 adapted to traverse scale 26. The arm 25 includes an upper slide surface section 27 suitably of smooth plastic such as methyl methacrylate. The term slide angle as used in this description and the appended claims will be understood to refer to methyl methacrylate as a reference though clearly other materials would serve the same purpose. The material 28 to be tested is wrapped around a 4-pound steel block 30 so that a planar lower side 29 contacts the section 27. Clamp 32 retains the test material in taut position. Raising of the arm permits evaluation in known manner of the angle at which slippage commences. Degree blocks as indicated at 31 may be used to support the arm 25 in upraised position. The higher the angle, the higher the resistance to slippage, and I have found that most soft, resilient foams have a slip angle of 50.degree.-55.degree.. This is in contrast to a wide variety of papers and films which have slip angles in the range of about 22.degree. to 33.degree.. A high differential of slip angle between the two surfaces of the protector sheet material is required, and I have found that the differential between kraft paper and polyurethane foam is about 31.degree. (55.degree.-21.degree.). In contrast, prior art materials used for protection have a differential of only about 1.degree. to 6.degree.; paper backed wadding, for example, has only a 2.degree. differential relative to methyl methacrylate (24.degree.-22.degree.). In general, I prefer that the slide angle of the foam be at least twice the slide angle of the paper backing; commonly, a difference in slide or slip angle of between about 25.degree. and 33.degree. is desired for my purpose.

In practice, the material specifically described herein has been employed in shipment of TV sets, pianos, dining room sets and the like without marring of the furniture.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments thereof except as defined in the appended claims.

Claims

I claim:

1. In combination with a shipping container having therein an article provided with a fine finish surface, a protector sheet material interposed between the fine finish surface and the inner wall of the container, the said protector sheet material having a paper element having two faces, one of said faces lying in contact with the interior wall of the container and the other face having secured thereto a foam ply, said foam ply being of greater thickness than the paper element, porous, easily compressible, resilient and having a greater slide angle than the face of the paper element which contacts the interior wall of the container such that s shifting of the article within the container causes sliding of the paper element relative to the container but no significant movement of the foam ply relative to the article surface whereby buffing, marking and scratching of the last mentioned surface due to the shifting of the article is inhibited.

2. The combination according to claim 1 wherein the slide angle of the foam is at least twice the slide angle of the paper element.

3. The combination according to claim 2 wherein the paper element is spot bonded to the foam ply and the bond of the paper element to the foam ply is sufficient to resist shearing action imposed on the protector sheet material by shifting of the article within the container, and the slide angle difference between the compressible foam and the paper element relative to methyl methacrylate is about 25.degree. to 33.degree..

4. The combination according to claim 3 wherein the ply of foam material has a thickness in the range of about one-sixteenth to one-fourth inch and the paper element has a lesser thickness.

5. The combination according to claim 1 wherein the slid angle of the foam is in excess of 50.degree. and the slide angle of the paper element is less than 25.degree., both relative to methyl methacrylate as a slide surface.

6. In a protector sheet material, a porous, resilient, easily compressible foam and a paper backing adhesively secured on one face of the foam only, said paper backing having an exposed surface which is readily slippable relative to a methyl methacrylate surface, said foam being relatively non-slidable with respect to the said methyl methacrylate surface, the foam having a thickness in the range of about one-sixteenth to one-fourth inch and the paper backing has a lesser thickness.

7. Protector sheet material according to claim 6 wherein the foam has a slide angle in excess of 50.degree. and the paper element has a slide angle of less than 25.degree. both relative to methyl methacrylate as a slide surface.