CA2018390A1 - Embossed closure profile and associated container - Google Patents

Abstract

EMBOSSED CLOSURE PROFILE AND ASSOCIATE CONTAINER

ABSTRACT

The instant invention relates to a closure device having opposed closure profiles which become engaged by pressing together wherein at least one of the outer contact surfaces has an embossed surface to improve the ease of engaging the closure profiles.
The closure device of the instant invention are suitable for use with a container, as hereinafter discussed.

Description

2~1g~90 EMBOSSED CLOSURE PROFILE AND ASSOCIATED CONTAINER

YIELD OF THE INVENTION
The instant invention relates to improved closure devices comprising two closure strips of the type employed for flexible container such as plastic bags. The outer contact surface of at least one of the two closure trips (also commonly referred to as "closure profiles") to be mated over a predetermined length is provided with an embossed pattern whereby the ease of mating the two closure strips is improved and whereby improved manufacture of such closure strips and related flexible containers is achieved.

DETAILED DISCUSSION OF THE INVENTION

It is well known in the prior art to form a closure device having interlocking or adhesive closure strips (a.k.a. "profiles") and more particularly to form a closure device including two closure profiles operable for being interlocked or mated continuously over a predetermined length.
Generally, an interlocking closure device for use in connection with flexible containers, such as plastic bags and the like, are well-known and several types are disclosed in the patent and non-patent literature. Interlocking closure trips are well known, as disclosed in U.S. Patent No. 4,212,337 and Re. U.S. Patent No. 28,969. Similarly, adhesive closure devices are well known as disclosed in U.S.
Patent Nos. 4,471,935 and 4,709,399.
It is also well-known that such closure devices may be interlocked or mated by a slider or they may be sliderless and of the type closed by use of human fingers, including a human thumb, being slid along 20~8390 the outer contact surface for the predetermined length to be interlocked or otherwise sated. When such closure devices are sliderless they are typically interlocked or mated by pressing together the two closure profiles at one end followed by running two fingers or a finger and thumb along each of the outer surfaces of the two closure profiles from one end to the other whereby the closure is interlocked or mated over its predetermined length.
Heretofore, the prior art has not considered the nature of the outer contact surface of the interlocking closure device as a means for improving the ease of engaging, e.g., interlocking or mating, the closure device or as to improving bag manufacturing processes. The instant invention addresses this issue and provides an embossed outer contact surface to improve the ease of closure use and the manufacturing handleability of the closure and or container having the closure device as an integral part.

SUMMARY OF THE INVENTION

Generally 6tated the instant invention relates to a closure device having closure profiles for becoming engaged, e.g., interlocked or mated by adhesion or other means, when pressed together wherein at least one closure profile has an embossed outer contact surface selected so as to reduce the contact area and surface friction on the outer 6urface of the closure profile. This reduction in surface friction is a reduction when as compared to the surface friction of the same surface without the embossed pattern when a second surface, e.g., a human finger or another bag surface, is slid across the ` 2~390, respective surfaces. The reduction in contact area of the area adjacent the closure device is a result of having the embossed pattern and not the entire surface as the area contacting the second surface.
The closure device may be connected to 6idewalls of a container to form a container having a closure device.
one embodiment of the instant invention comprises an interlocking closure device comprising two closure profiles operable for being interlocked continuously over a predetermined length (wherein optionally the closure profiles may have different colors, whereby the position of the profiles on a container can be easily identified visually to simplify the closing and opening of the container and/or the complete occlusion of the closure profiles can be easily verified visually) wherein the closure profiles have outer contact surfaces having at least one outer contact surface having an embossed surface.
A further embodiment of the invention is a container comprising two flexible sidewalls, and an interlocking closure device such as those disclosed in U.S. Patent Nos. 4,186,786, 4,285,105 and 4,829,641, including two closure profiles operable for being interlocked continuously over a predetermined length connected to the sidewalls, the closure profiles having different primary colors selected to produce a predetermined 6econdary color, whereby the complete occlusion of the closure profiles can be identified visually easily and wherein the closure profiles having outer contact surfaces are further characterized as having at least one of said two closure profiles having an embossed outer contact surface or being contacted by a user of the closure profile during interlocking of the two closure profiles over a predetermined length whereby the ease of passage of the user's fingers over the

- 3 -2~1~3~ 1 outer contact 6urface is improved over as a result of providing the embossed pattern.
Another embodiment of the invention comprises a container comprising two flexible sidewalls and an adhesive closure device including two closure profiles having outer contact surfaces operable for beinq engaged continuously over a predetermined length connected to the sidewalls, wherein at least one outer contact surface has an embossed surface.

DESCRIPTION OF THE DRAWINGS

FIG. l i8 a perspective view of a flexible container including a closure device in accordance with the invention with embossed outer contact surfaces adjacent the interlocking closure profiles;
FIGS. 2(a), 2(b), 2(c) and 2(d) are diagrammatic and sectional views of closure devices in accordance with the invention wherein embossed outer contact surfaces are provided on interlocking closure profiles;
FIG. 3 is a perspective view of a flexible container having a gusseted bottom and including an embossed closure device with embossed outer contact surface in accordance with the invention;
FIG. 4 is a side elevational view of a closure profile of FIG. l with an embossed outer contact surface in accordance with the instant invention;
FIG. 5 is a perspective view of a flexible container including a closure device with an embossed outer contact surface wider than the width of the base of the interlocking closure profile;
FIG. 6 is a side elevational view of the flexible container with embossed closure device of FIG. 5;
FIG. 7 is a schematic view of an apparatus for

- 4 -- 20:183~0 !
practicing one aspect of the invention;
FIG. 8 is an enlarged perspective view of an embossing roll hown in FIG. 7; end FIG. 9 is FIG. 17 of U.S. Patent No. 4,829,641.

DETAILED DESCRIPTION OF THE INVENTION

Generally stated the instant invention relates to a closure device having closure profiles for becoming engaged, e.g., interlocked or mated, when pressed together wherein at least one closure profile has an embossed outer contact surface. The embossed outer contact surface provides a reduction in the frictional forces between the outer surface of the closure profile and another surface contacting said tame, as compared to the friction between the same surfaces without the embossed pattern. The closure device may be connected to sidewalls of a container to form a container having a closure device, such flexible containers heretofore known in the prior art.
The instant invention also relates to a container including a closure device having two closure profiles which are capable of being engaged over a predetermined length by the fingers of a user wherein the closure device $s characterized as having an embossed closure profile so as to enable the user to occlude the closure device easily by reducing the friction experienced as the user finger are slid along the outer contact surface of the closure profile(s) during the engagement of the closure profiles.
As used herein, the term "closure profiles" $s used to designate two closure strips which are designed to engage $n a locking or other mating manner when pressed together and includes, but is no

- 5 -- 2~183~

limited to, both adhesive closure trips and to interlocking closure strips. Interlocking closure strips are generally characterized as having respective cross 6ections which enable the interlocking closure profiles to be interlocked over a predetermined length. The closure profiles may be capable of being separated after engagement or may be permanently engaged after being pressed together, i.e., engaged. The closure profiles can include flanged portions, rib portions and other features, as hereto known in the art, and, further, can be connected to a sidewall of a container or to other surfaces to be engaged, e.g., portions of an article of clothing or various types of covers.
As used herein, the term connected" includes an integral combination obtained from extrusion through the same die opening as well as adhesive or cohesive or lamination connections.
As used herein, the term "outer contact surface"
is meant to designate the side of the closure profile opposite the portion having the means for engagement with a second closure profile. It is the "outer contact surface" to which pressure is applied to engage the closure profiles to provide a closure line between two closure profile engagement surfaces. For example, in FIGS. 2(a), 2(b), 2(c) and 2(d), the outer contact surfaces are respectively designated as: 22-A and 27-A; 24-A and 26-A; 27-A and 29-A; and 33-A and 34-A. As noted by reference to these figures, the outer contact surface may be on the closure profile itself or may be on the outer surface of sidewall of a flexible container atop the closure profile when the closure profile is placed on the inside surface of the flexible container's sidewalls. Similarly, the outer contact surface for an adhesive closure i5 the non-adhesive side of the

- 6 -- 2~:~839~

closure to which pressure is supplied on the two mating closure profiles to adhere the two closures at an interface of their respective adhesive engagement surfaces.
As used herein the term "color" in relation to color change closures and other portions having color includes clear transparent and tinted transparent and, 6imilarly, clear translucent, tinted translucent and opague. The term "color" in reference to color change closures is readily understood by reference to U.S. Patent Nos.: 4,186,786; 4,285,105; and 4,82~,641.
The nature of the embossment to be provided to the outer contact surface is characterized as being selected 80 as to provide a reduction in the coefficient of friction of the outer contact 6urfa~e as a result of the embossed surface being provided to the outer contact surface, i.e., the coefficient of friction is reduced as compared to the same surface sans the embossed pattern. This functional relationship of the emboæsed outer contact surface to the use of the closure device or a container having such a closure device as a part thereof may be achieved with a wide range of embossed patterns formed by both physical and chemical treatments. The embossed pattern may be a diamond pattern, (commonly called a "criss-cross" pattern), grit blasted pattern, various geometric patterns and non-geometric patterns heretofore known in the art. A grit blasted pattern is characterized by a micro roughness of the surface of the embossing surface to be used to provide the embossed outer contact surface. It has also been observed that it is not necessary that the embossed pattern be uniform on the entire outer contact surface. For example, the embossed pattern should be along a major portion of the length of closure device (e.g., from one side to the other side

- 7 -2 0 1 g 3 O
edge when on a container) but need not be across the entire width of each closure profile of the closure device. It has been observed that during the manufacture of a flexible container having a closure device that the interactive nature of a closure profile, the outer surface of the container sidewall adjacent a closure profile and the embossing characteristics of the embossing roll may create a non-uniform embossed pattern on the outer contact surface. This interaction may result in an embossed pattern next to the closure profile area of the closure device having a greater embossed pattern than provided on the outer contact surface on the sidewall directly atop the base of the closure device which is on the inner surface of the container sidewall. This effectively results in two different embossed patterns owing to the differences in the actual depth of the embossed pattern in the two areas of the outer contact surface. Similarly, it is within the scope of this invention to employ two or more different embossing patterns on the same embossing roll or on different embossing rolls whereby the outer contact surface will have two or more different embossments, e.g., both a diamond embossed pattern and a grit blasted embossed pattern. Further, it has been observed that a single embossed pattern may be provided by superimposing one embossed pattern on another embossed pattern to form a new embossed pattern. For example, in one embodiment the embossing roll is provided with a diamond pattern and then provided with a second embossed pattern by grit blasting the diamond pattern. In one embodiment a diamond pattern is engraved in the embossing roll to have a depth of about 0.010 to O.011 inches. Owing to observed differences in the pressure of the embossing roll against the flange adjacent the edge

- 8 -2~ ~3~

of the base of the closure profile as compared to the pressure on the closure profile's base there i6 an observed difference in the depth of the embossed pattern in the outer contact 6urface, i.e., the embossed pattern i6 not uniform. When the flanye is about 0.~05 to 0.007 inch thick the aforementioned embossing pattern will typically form a pattern 0.003 inch deep while the depth of the embossing pattern directly atop the closure profile base portion will typically be less than 0.003 inch thick. Such non-uniform embos6ed outer contact 6urface areas are suitable for use in the instant invention. Further, when the embossed pattern is formed from a grit blasted or a non-uniform pattern it may not be convenient to measure either the depth of the embossed pattern on either the embossing roll or the embossed outer contact 6urface, although such an embossed pattern may provide a suitably embossed outer contact surface for the improvements accomplished by the instant invention and, accordingly, are within the scope of the instant invention.
One embodiment of the instant invention comprises an interlocking closure device comprising two closure profiles operable for being interlocked continuously over a predetermined length (wherein the closure profiles may have different colors, whereby the position of the profiles on a container can be easily identified visually to simplify the closing and opening of the container and/or the complete occlusion of the closure profiles can be easily verified visually) wherein the closure profiles have outer contact surfaces having at least one outer contact surface having an embossed surface.
Another embodiment of the invention is a container comprising two flexible sidewalls and an _ g _ interlocking closure device including two closure profiles having outer contact surfaces operable for being interlocked continuously over a predetermined length connected to the sidewalls, wherein the container comprises the closure profiles which may be different colors whereby the position of the profiles on the sidewall can be identified visually easily to simplify the closing and opening of the container) wherein at the two outer contact surfaces of the closure profiles have an embossed outer contact surface.
A further embodiment of the invention $s a container comprising two flexible sidewalls, and an interlocking closure device having two closure profiles operable for being interlocked continuously over a predetermined length and connected to the sidewall, the closure profiles having different primary colors are selected to produce a predetermined secondary color, whereby the complete occlusion of the closure profiles can be identified visually easily and wherein the closure profiles are further characterized as having at least one of said two closure profiles having an embossed outer contact surface for being contacted by a user of the closure profile for interlocking the two closure profiles over a predetermined length. Representative of said interactive colored closure profiles which may be employed in this embodiment are those disclosed in U.S. Patent Nos. 4,186,786; 4,285,105 and 4,82g,641.

Another embodiment of the invention comprises a container having a closure device wherein one or both of the closure profiles of the invention includes a flange portion (which may be embossed), rib portions, spacer members, aligning members and other closure related features heretofore employed in the use of , -- 1 0 2 0 a closure devices and containers employing closure devices. In addition, the bag body may be an embossed film and may also have other features such as write-on areas, gussets, lower corner tabs for heat isolation, multiple compartments and the like, as heretofore known on the art. In one embodiment of the instant invention the embossed outer contact surface is provided Jo as to extend from below the closure profile, i.e., it least some portion of the outer surface of the sidewall below the closure profile has an embossed pattern, and extends from this area to the mouth portions of the sidewalls whereby both this lower sidewall portion the area atop the closure profile and the flanges are embossed.
A further embodiment of the instant invention comprising an adhesive closure device comprising two closure profiles operable for being adhesively mated over a predetermined length wherein the closure profiles having outer contact surfaces have at least one of the outer contact surfaces characterized as having an embossed surface according to the instant invention.
The invention accordingly comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in a construction hereinafter set forth and the scope of the application of which will be indicated in the claims.
Generally, closure devices and thermoplastic films, such as those employed in the instant invention can be made from the various thermoplastic material, including polyethylenes (including, but not limited to, the linear low density, medium density and high density, although linear low density polyethylene is preferred for its cost and overall beneficial balance of chemical and physical properties), polypropylene, and other flexible thermoplastic materials or the like and mixtures or blends thereof. When the closure device is an adhesive closure device an appropriate adhesive material will be employed.
The thermoplastic material may alto contain one or more additives as heretofore employed in the prior art, including but not limited to, slip agents, anti-block additives, anti-oxidants, colorants, dyes and the like. It is believed that the instant invention may beneficially result in a reduction in the amount of certain additives hereto required to be employed in the manufacture of closure devices and/or containers having closure devices owing to the observed reduction in friction of the outer contact surface of the closure devices and containers of the instant invention. For example, it is believed that the use of the embossed outer contact surface may result in a reduction in the amount of anti-block and/or 51ip agent heretofore used.
The closure device can be of the type in which one closure profile partially encircles or interlocks in some fashion with the other closure profile (commonly referred to as "interlocking closure devices") or involves the engagement or mating of two closure profiles by use of adhesive means (commonly referred to as "adhesive closure devices").
Representat;ve of interlocking closure devices are those shown in U.S. Pat. Nos.: Reissue U.S. Pat. No.
Re 28,969; 2,978,768; 3,038,225; 3,416,199;
3,338,284; 3,338,285; 3,565,147; 3,780,781;
4,561,108; 4,212,337; 4,363,345; 4,578,813;
4,362,198; 4,484,352; 4,516,268; 4,561,109;
4,733,778; 4,736,450; 4,787,880; 4,822,539 and 4,829,641. For example, the closure device can be of the type in which each of the closure profiles includes a plurality of hook portions and the closure profiles engage to establish occlusion on a line of closure, as shown in U.s. Patent No. 3,054,434, u.S. Patent No. 4,212,337 and in U.s. Patent No. 4,829,641.
Adhesive closure devices are well known in the prior art as is the use of such adhesive closure devices on flexible containers. Representative of such adhesive closure devices are disclosed in U.S.
Patent Nos.: 4,674,634; 4,708,70S; 4,709,399: and 4,741,935.

The use of an embossed outer contact surface for closure profiles is believed to be advantageous for both a sliderless closure device as well as a closure device having a slider. The use of embossed outer surfacPs for the closure profiles is advantageous because the embossed outer contact surface acts to reduce the surface friction on the outer contact surface of the closure profile when beinq engaged by use of sliding the fingers or a mechanical clider over a predetermined length of the closure device.
It is also believed that this reduction in surface friction arises from the reduction in surface area contacted by the slider or user's finger(s).
The lower surface friction of the outer contact surface is also beneficial in manufacturing steps typically employed in the manufacture of bags having a closure device. The folded web stock used for manufacturing such bags closure bags") is typically continuously manufactured by extrusion at a high bag rate (i.e., bags/minute) with air or water cooling of the bag film and closure device . the closure bags are typically manufactured by cutting off successive bags from a continuous folded web stock followed by 20~ 839~ 1 stacking the finished closure bags by sliding or placement of one atop another, wherein the outer contact surfaces of the closure profiles of respective closure bags come into contact as the closure bags are 6tacked. When the outer contact surfaces are smooth and glossy, they do not easily 61ide over each other, QVen when significant amounts of slip agent and antiblock are present in the thermoplastic material. When the closure bags are manufactured at a high bag rate in conjunction with an in-line extrusion process for the folded web stock, the base of the closure profile i6 prone to being "tacky" as a result of the relatively thick closure profile not being sufficiently cooled, because the slip agent in the thermoplastic material has not had sufficient time to migrate to the surface of the closure profile or bag film surface (commonly referred to as "bleeding to the surface") and, further, because antiblock additives have variable effectiveness depending on processing variables.
When the outer contact surface has an embossed surface the ease of sliding of the outer contact surface of another closure bag is substantially improved. The use of the embossed outer contact surface in the manufacturing process provides improved processing of the closure bags which results in increased rates of manufacture and ease of handling of the closure bags during manufacture. In addition, it is believed that the embossed outer contact surface wends to reduce the sticking of the outer contact surfaces as between closure bags after the closure bags have been 6tacked and aged for a period of tiDe.
In carrying the invention into effect, certain embodiments have been selected for illustration in the accompanying drawings and for description in this D-lS588 201g390 specification, reference being had to FIGS. 1 to 9.
Although FIGS. 1 to 9 show the closure device as an interlocking closure device, it will be understood that other closure devices may be substituted for the interlocking closure device in accordance with the instant invention.
FIG. 1 shows a typical flexible container 10 formed from a thin, transparent, plastic film which has been folded to define a bottom portion 11 and heat sealed along vertical side edges 12 to form a pouch.
The sidewalls 13 extend beyond a sliderless closure device 14 to provide flanges 15 and mouth portions 16 and 17 to simplify the opening of the closure device 14.
The closure device 14 includes closure profiles 18 and 19 (closure profile 19 shown with an embossed outer contact surface) and may comprise any closure device including those closure devices incorporated above by reference thereto. In accordance with the art, the end portions of the closure profiles 18 and 19 may be connected to each other although it is Xnown that such end portions may be left unconnected.
The closure profiles 18 and 19 may be different colors or haze colored ribs so as to be easily identified visually, although such is not required to achieve the improved ease of closing achieved by embossing the outer contact surfaces of the closure profiles. The sidewalls 13 are typically transparent but could be made translucent with colors or tints, or could be themselves embossed or be made opaque.
If the closure device is to be a color change closure device and sidewalls 13 are to be opaque, then it is advantageous that at least one of the closure profiles should be a color which can be easily distinguished from the 6idewall region adjacent to - 2~183~0 1 it U.S. Patent Nos. 4,186,786 and 4,829,641 aforementioned, disclose flexible containers having such color change closure devices.
Preferably, the sidewalls 13 are transparent or translucent at least in the region adjacent to the closure profiles 18 and 19 and may have an embossed pattern.
FIGS. 2(a), 2(b), 2(c) and 2(d) show different embodiments of the interlocking closure devices of the instant invention. FIG. 2(a) shows closure profiles 27 and 22 which are flangeless and may be connected to opposite inside or outside sidewall of a container or other surface and have outer contact surfaces 22-A and 27-A, respectively. FIG. 2(b) shows closure profile 23 including a flange portion 24 and flangeless closure profile 26, having outer contact surfaces 24-A and 26-A, respectively. FIG.
2(c) shows flangeless closure profile 27 and closure profile 28 including a flange portion 29, having outer contact surfaces 27-A and 29-A, respectively.
FIG. 2(d) show closure profiles 31 and 32 including flange portions 33 and 34, respectively, and having outer contact surfaces 33-A and 34-A, respectively.
Although not shown in FIGS. 2(a), 2(b), 2(c) and 2(d) the closure profiles may be employed on, i.e., affixed to, the inside or outside of the container sidewalls or when the closure profiles are suitably fielected employed on the outer surface of the container sidewalls with the container sidewalls being between the two closure profiles when engaged, e.g, interlocked. In thi& later embodiment, the outer contact surfaces 22-A and 27-A of closure profiles 22 and 27 (referring to FIG. 2(a), i.e., the surface not having the hook projections for interlocking said closure profiles) are embossed with the selected embossed pattern.

2~39~ 1 Preferably, the flange portion 15 is clear transparent, but the flange portion could be tinted 60me color or even be opaque. The flange portion could be embc~-sed (not shown) and/or have a predetermined color while the remainder of the closure profile i6 transparent, translucent, opaque or combinations of the aforementioned.
In the instant invention the portion of the closure profile or container sidewall associated with the closure profiles for engagement over a predetermined length by contact with a mechanical slide or the human hand will have at least one closure profile having an embossed pattern(s) associated with the outer contact surface.
FIG. 3 shows a container 36 similar to the container 10, but including a gusseted side 37 with rectangular bottom 37-A to provide a stand-up, gusseted interlocking closure bag.
FIG. 4 shows closure profile 22 of FIG. 2(a) in which the female closure profile 22 having borders 38 and 39 on opposite sides of portions of the male closure profile 27 showing embossed pattern 22-A when closure profiles 22 and 27 are interlocked.
Because in one embodiment the closure profiles 22 and 27 shown in FIG. 1 are different colors 50 as to provide a color change closure device, the completeness of the occlusion can be easily verified visually by observing the relationship between the continuous borders 38 and 39 and the embossed region 22-A, wherein, with respect to the closure profile 22 and outer contact surface 22-A, the selection of the embossed pattern is made 80 as not to interfere with visual observation of the color change. Preferably, the closure profiles 22 and 27 should be contrasting colors to optimize the ease in visually identifying the completeness of the occlusion such as described ; 20183~0 ) in U.S. Patent No. 4,829,641. In one embodiment the closure profiles are different colors but do not provide a third color upon engagement.
Referring to FIGS. 1 and 2(a), in one embodiment the interlocking closure device comprises closure profiles 18 and 19 of the type shown in FIG. 2(a), the sidewall of a container used in connection with closure profiles 22 and 27 comprise a color change closure device and the sidewall6 should preferably be transparent or translucent at least in the region adjacent to the closure profiles 22 and 27 to improve color charge perception. Closure profiles 22 and 27 in this embodiment can be primary colors and sufficiently translucent so that the occlusion of the closure profiles 22 and 27 produces a viæible secondary color. Thus, the completeness of the occlusion can be determined visually easily by observing a continuous region of the secondary color bordered on each side by one of the primary colors depending upon the side being viewed.
FIG. 5 shows a typical flexible container 40 formed from a thin thermoplastic film which has been folded to define a bottom portion 41 and heat sealed alonq vertical side edges 42 to form a bag and having an embossed outer contact 6urface comprising the outer surface of the bag film and having a width wider than the width of the base of the closure profile affixed to the inner sidewall surface. The film may also be tinted or embossed if so desired.
The sidewalls 43 extend beyond a closure device 48 to provide mouth portions 46 and 47 to simplify the opening of the closure device having closure profiles 48-A and 48-B (shown in FIG. 6). A flange portion 45 is shown below the mouth portions 46 and 47 and may have ribs or ridges and the flanges may be themselves embossed or contain an anti-slip surface 6uch as described in European Patent Application 83102845.1, published September 28, 1983, -incorporated herein by reference.

Closure device 48 includes two clc,ure profiles (only closure profile 48-B shown in FIG 5) cld is preferably a closure device as described in U.S.
Patent No. 4,829,641. In accordance with the prior art, the end portions of the closure profile may be connected to each other, although it it known that such may be left unconnected.
The closure profiles of closure device 48 may be different colors to be easily identified visually, although uch is not required to achieve the improved ease of closing, i.e., interlocking achieved by embossing the outer contact surfaces of the closure profiles. The sidewalls 43 are typically transparent but could be made translucent with colors or tints, or could be themselves embossed or even be made opaque. If the closure device is to be a color change closure device and sidewalls 43 are to be opaque, then it is advantageous that at least one of the closure profiles should be a color which can be easily distinguished from the sidewall region adjacent to it. U.S. Patent Nos. 4,186,786 and 4,829,641 disclose container having such colored closure strips.
Preferably, the sidewalls 43 are transparent at least in the region adjacent to the closure profiles of closure device and may be transparent with an embossed pattern.
FIG. 6 is a side elevational view of a portion of FIG. S showing flange 45, mouth portion 47, closure profile 48-B connected to sidewall 43 wherein the embossed outer contact surface 49 is on the -' 2ol~39ol surface of the sidewall adjacent closure profile 48-B
and is shown as being wider than the closure profile with the embossed outer contact surface extending both above and below the width of the base of the closure profile, although such is not required. In addition, the flange area may be embossed (not shown) up to mouth portion 47.
FIG. 7 6hows a schematic view of apparatus for continuously embossing or engraving the outer contact surface associated with a closure device, 8.g., an interlocking closure device, and/or a closure bag.
There is shown a reclosable container 6toc~ supply 51 (source not shown) which may be a folded web stock or a closure profile supply 51 (source not shown) being fed to the nip of two pull rollers wherein one roller is a resilient rubber-backed roller 52 and one roller i8 a non-yielding embossing roller 53 having on its surface an embossing pattern 54 on one portion thereof as shown in FIG. 8. When the closure device is an interlocking closure device, the embossing roller 53 also preferably has a peripheral groove 55, as shown in FIG. 8, located around its circumference to accommodate the closure profile element and to avoid damage to the closure profile(s) during embossing. Similarly, when ribs or spacing portions are provided it is preferred to provide a groove (not shown) for accommodating such to avoid damage to such during the embossing process. The other portion of the embossing roller is shown as smooth, as depicted at surface 56 in FIG. 8, although such could be embossed if it is desired to provide the sidewall (6) with an embossed surface. As shown in FIG. 7, container 6tock supply 51 or tape supply 51 i6 fed to the nip of rubber-backed roller 52 and embossing roller 53 whereby an embossed pattern is produced on the contact surface of the container stock supply 51 associated with closure profile 31 and, optionally, on the flange portion of the container sidewall. An embossed pattern 54, shown a6 a diamond pattern in FIG. 8, i6 provided on the outer contact surface.
As shown in FIG. 7, the emboæsed outer contact surface is provided with the embossed pattern by feeding reclosable container stock or closure device between the nip of a pair of rollers wherein at least one of the rollers bears an embossing or engraving pattern thereon, end one or both rollers have grooves therein to accommodate the occludable closure profiles of the interlocking fastener device to thus avoid damaging the occludable closure profiles. It should be noted that it is not necessary that the embossing step be carried out at the point in the process where the film or closure is still warm. Alternatively, a heated embossing roller may be provided at another point in the manufacturing process whereby the embossed pattern may be formed on the outer contact surface.
Following the embossing step, the male and female closure profiles may be occluded by passing through occlusion rollers and the occluded container stock or interlocking closure profiles is then directed to a wind-up device for storage, or is directed to further processing eguipment.
The improved containers of this invention are provided with an embossed outer contact surface for use by the user, thereby providing easier closure of the container. In one embodiment the flange surface areas may be provided with embossing or engraving on the flange for providing improved ease in opening the container.
- Typically, when the container is a food storage container, the container 10 (shown in FIG. l width is about 10-9/16 inches and the height is about - 2~ -11-1/2 inches. The dimensions of various commercially available bags are well known. The closure device is typically located about 5/8 to one inch below the top edge of the grasping flanges.
Referring to FIG. 1, operation of the container according to the invention i8 as follows:
A user in the process of closing the container 10 with closure profiles 18 and having an embossed outer contact surface can interlock an end portion, adjacent side edge 12, of the two closure profiles at one end and than easily interlock the closure prsfiles over a predetermined length by running the closure profiles between a thumb and a finger along the two closure profiles from one side edge to the other side edge. The relatively small spacing between closure profiles results in alignment from the small portion initially pressed together as to result in easily interlocking the closure profiles by sliding the thumb and finger along the embossed outer contact surfaces of the closure profiles. The embossed outer contact surface it an excellent sliding surface for the thumb and/or finger. The user may then open the bag by separating the top edges by grasping the flanges and pulling them apart to disengage the closure profiles from each other.
The embossed outer contact surface reduces the frictional forces experienced by the user as pressure is applied to the outer contact surface as the user slides a finger and/or thumb over the outer contact surface(s) of the closure profile.
The containers and closure devices employed in this invention may be prepared by any suitable manufacturing method, including that disclosed in U.S. Patent No. 4,676,851. For example, each closure profile can be manufactured as I.

a strip for subsequent attachment to a film by the use of appropriate attaching means. Typically, a thermoelectric device can be used to apply heat to a film in contact with a closure strip to cause a transfer of heat through the film to produce fusing at the interface of the film and the closure 6trip.
The fusing of the film and the closure profile may also be effected by coextrusion of a molten closure profile onto a molten film or may be effected by the use of hot melt adhesives, hot air sealing, or other methods such as ultrasonic heating.
The manufacturing operation, broadly speaking, involves adhering each closure profile, e.g., an interlocking cloture profile, which i6 in a molten or non-molten state, to a molten or non-molten film of thermoplastic material. The process is typically a continuous process and employs a slot film casting station and at least one grooved lay-on roll and at least one roll for applying the embossment to the outer contact surface. In one embodiment, an interlocking closure device having closure profiles with flange portions are fed to lay-on rolls having circumferential grooves therein to accommodate the contours of the closure profiles. A molten thermoplastic film is extruded onto a rotatable casting cylinder positioned opposite the lay-on rolls so that the thermoplastic film becomes fused to the flange portions of the closure profiles, and thereafter the combination of thermoplastic film and closure profiles is cooled. (Alternatively, closure profiles, and optionally, ribs and the like, may be directly extruded onto the plastic film). The lay-on rolls, may be as wide as or wider than the specific closure profile to be affixed to the molten thermoplastic film or may be wider 80 as to contact the other portions of the thermoplastic film.

Further, the lamination pressure exerted by the lay-on rolls on the casting cylinder, with the closure profiles and thermoplastic film therebetween, may be controlled by spacing means such as jacking bolts or air cylinders which prevent damage to the closure profiles and the thermoplastic film. The casting cylinder is rotated at substantially the same surface speed as the fed closure profiles, whereby the closure profiles are laminated to the thermoplastic film cast on the casting cylinder. The combination of closure profiles and thermoplastic film is then advanced to further cooling means such as a chill roll. The afore-described method for providing plastic film with occludable closure strips fused thereto, pursuant to U.S. Patent No. 4,676,8S1, m a y b e e m p 1 o y e d herein to provide the sidewalls of the container with at least one embossed urface such as embossed outer contact surface, as shown in FIG. 1 (in relation to closure profile 19) or outer contact surface 49 as shown in FIG. 5 and FIG. 6. The embossed outer contact surface may be obtained by providing an embossing or engraving pattern on at least one portion of the aforementioned casting cylinder, forming or feeding preformed closure profiles having flange portions to a rotatable circumferentially grooved lay-on roll so that the unoccluded closure profiles extend into the grooves of the lay-on roll, extruding a molten thermoplastic film onto the rotatable casting cylinder positioned opposite the lay-on roll so that the molten thermoplastic film fuses to the flange portions of the closure strips, and thereafter cooling the laminated composite of thermoplastic film and closure profiles.
The embossing or engraving pattern on at least one portion of the surface of the casting cylinder 2018~0, may be one as earlier discussed, e.g., a diamond pattern as depicted in FIG. 7. The other portion of the surface of the casting cylinder can be smooth or may be embossed to provide an embossed pattern to the sidewalls of a flexible container if such is being formed. In addition, the surface of the casting cylinder may have more than one portion thereof having an embossing or engraving pattern thereon, i.e., two or more different embossed patterns. In any event, as the molten plastic film it extruded onto the casting cylinder having an engraving or embossing surface portion, and as the molten thermoplastic film contacts the closure profiles carried by the lay-on roll, pressure contact therebetween fuses the cast molten plastic film to the closure profiles and also embosses the opposite surface of the cast film adjacent the closure profile to provide an embossed outer contact surface.
As shown in FIG. 5 herein with respect to embossing roller 33, the engraving or embossing pattern on the Qurface of the casting cylinder is shown as closely spaced diagonal criss-crossed lines and has intervening smooth areas (commonly referred to as a "diamond pattern"). The engraving or embossing pattern on the surface of the casting cylinder may be provided with from between about 14 to about 56 lines per square inch in each diagonal direction and in one embodiment with between about 30 to about 40 lines per inch in each diagonal direction. An embossed pattern for an embossing roll suitable for use in providing an embossed outer contact surface in accordance with the instant invention has an embossed diamond pattern having about 36 lines per inch in each diagonal direction (available as diamond pattern P36 from PAMARAC0, Inc., 209 East llthe Avenue, Roselle, New Jersey, followed by grit blasting the diamond pattern using PAMA 14 (available from PAMARACO, INC.), chrome plating the grit blasted diamond pattern and then again grit blasting (per PAMA 14) the chrome-plated-grit-blasted diamond pattern.
The manufacturing method may al80 employ 81 itters to remove trim such 8S edge beads and to slit the bag stock to provide multiple products having closures. For example, a pair of deoccluded interlocking closure profiles may be fed into the grooving of a plurality of rubber-covered lay-on rolls which align the closure profiles into the proper lateral positions prior to contact and lamination with the molten cast thermoplastic film.
Obviously, any number of such lay on roll arrangements may be employed on a common shaft.

FIG. 9 is Figure 17 of U.S. Patent No.
4,829,641 with the numbering shown thereon being as shown in U.S. Patent No. 4,829,641.
In one embodiment of the instant invention the interlocking closure device of FIG. 17 is employed as the closure device on a container, such as shown in FIG. 1 or FIG. 5 of the instant application. An embossed surface is provided on the outer contact surface of sidewalls at flange portions 352 and 382, whereby the outer contact surfaces (the non-closure profile sides of sidewalls at 352 and 382) have an embossed 6urface according to the instant invention.
Various alternatives may be practiced pursuant to this invention. For example, each closure profile portion may be extruded directly, into the area previously described as the lanination area, simultaneously with the cast thermoplastic film while providing appropriate embossing and cooling means therefor. These molten thermoplastic streams are 201 8t~90 combined to form an integral thermoplastic web which is then cooled and processed further. As in the aforementioned method, the casting cylinder may be provided with an embossing or engraving pattern on a portion of its surface and produce the embossed outer contact surface of the closure profile on the outer surface of the sidewall of the ultimate container.
Preferably, at least a portion of the casting cylinder has a matte, textured, embossed, or engraved surface to provide the desired embossed outer contact surface of the closure profile areas for the container, although a separate embossing step may be employed. Alternatively, the embossed pattern on the outer contact surface may be provided by means of heated embossing roll after the bag stock for manufacturing the closure bags is formed or the closure bags are manufactured. The container stock may also be fed directly to a container forming/cut-off mechanism such as a bag-making machine.
Containers prepared in accordance with this invention may be used in the packaging and storing of a variety of articles and products.
Moisture-containing foods including fruit such as apples, pears, peaches, plums, tomatoes; meats:
vegetables 6uch as carrots, peas and string beans may be conveniently packaged and maintained in sanitary condition in such containers.
The following example is provided to illustrate the instant invention and are not intended to be limiting thereof.

The reduction in the coefficient of friction of the outer contact surface of the closure profile was ` 20~90 determined by contacting the outer contact surfaces of two closure profiles one on top of the other and dragging one relative to the other. The lower closure profile is secured in a support grooved to accommodate and position the closure profile. The upper closure profile is in a similar grooved support (~sledn) jut is provided with wheels aligned to make the sled move parallel to the closure profile mounted therein. the wheels are positioned to follow grooves in the support for the lower closure profile, these grooves being parallel to the lower closure profile and positioned laterally so that the upper and lower closure profile outer contact surfaces rest against each other. The wheels on the sled are elevated so that only those on one side of the sled can rest on the bottom of the wheel groove at a given time while the wheels on both side still maintain guidance from the sides of the wheel grooves. In this way the wheels guide the sled without reducing the load applied to the upper and lower closure outer contact surfaces in contact and being tested. Further, the depth of the closure grooves and orientation of the closure profiles are adjusted such that the tested outer contact surface is only that at the base of a closure profile and does not include flanges or other surface areas not directly atop the base of a closure profile. A measured load (200 grams) is applied my the upper support, i.e., sled, and the resistance to dragging the sled measured and the Coefficient Of Friction (COF) calculated as a ratio of drag force to applied load for each sample. A total of three (3) test specimens were evaluated for each of Samples A, B and C, the range of individual points recorded and an average value calculated. All sample specimens were made with the male or female closure profile as shown in FIG. 17 of U. S. Patent No. 4,829,641.

- .
2~l~3~ol Sample A was made with a mirror surface casting roll with no engraved pattern and represents the prior art and a comparative control sample. Sample A was manufactured using a linear low density polyethylene resin having a high concentration of slip agent (about 1500 ppm by weight erucamide) and an antiblocking additive (10,000 ppm by weight of a diatomaceous earth). Sample B was manufactured the same as aforementioned Sample A except the 81ip agent concentration was 700 ppm and the antiblock concentration was 4500 ppm. The lower concentrations of slip agent and antiblock would be expected by those skilled in the art to result in significantly higher Coefficient of Friction for the bag surfaces.
Further, the outer contact surface of Sample B of the closure device was melt embossed. The embossed outer contact surface of Sample B specimens was on the outer surface of the container sidewall and included the area atop the base of the closure profile and about 0.5 inch on either side of the base of the closure profile, although the area tested was only the width of the closure. FIG. 6 shows an embossed outer contact surface on the outer surface of the sidewall wherein the embossed pattern extends above and below the width of the base of the closure profile). The embossed pattern for Sample B is characterized as a diamond pattern having 36 lines per inch in each diagonal direction (available as diamond pattern P36 from PAMARAC0, INC., 20~ East llthe Avenue, ~oselle, New Jersey), followed by grit blasting the diamond pattern using PAMA 14 (available from PAMARACO, INC.), chrome plating the grit blasted diamond pattern and then grit blasting (again using PAMA 14) the chrome-plated-grit-blasted diamond pattern a second time. A third Sample C was evaluated wherein Sample C comprised the embossed male closure profile of Sample B and the non-embossed female closure - - - 201~3~

profile of Sample A. The 6pecimens of Samples A, B
and C were aged about three (3) weeks after being made before testing whereby the 61ip agent is believed to have migrated to the surface of the outer contact curface. The following results were obtained:
TABLE Il Coefficient of Friction Test 1 Test 2 Test 3 Sample (Av. Ranqe) (AY. RanaeL (Av. Ranae~ Averaae A 0.475 0.36 0.43 0.422 (0.365-0.62) (0.31-0.49) (0.295-0.605) B 0.145 0.120 0.125 0.130 (o.100-0.21) (0.07-0.18) (0.08-0.18) C 0.155 0.175 0.195 0.175 (0.13-0.21) (0.145-0.24) (0.15-0.27) 1 The "Final Average" value is the average of the average values of Test 1, Test 2 and Test 3.
From the above results it is evident that the addition of the embossed pattern on the outer contact surface of the female and/or male closure profile results in a significantly reduced COF. In fact, the COF between unembossed surfaces gave an average COF
value of 0.422, the average COF value of the embossed female and male closure elements were 0.130 and when only one embossed closure profile was present the average COF value was 0.175.
The considerably lower COF values indicate improved ease of closure for a closure device when a 61ider or user's hand i8 drawn across the outer contact surface to cause the closure profiles to engage, or, as in the instant example to interlock.
The ~ignif~cantly lower COF is also beneficial in the manufacturing processes typically employed in the manufacture of bags having a closure device.
When closure bags are made in conjunction with an in-line extrusion process for the folded web stock 2~18~

(i.e., a fold cver web of film with mating closure profiles spaced near the open edges) wherein the closure bag is formed between about 20 and about 120 seconds after the web of film and closure profiles ore extruded, the Coefficient of Friction of the outer contact surfaces are both higher and more variable than those observed when the same specimens are aged. Accordingly, such on in-line process will benefit to a significant extent from the reduction in the Coefficient of Friction of the embossed outer contact surface, since the 61ip agent present in the thermoplastic material will not have had sufficient time to migrate to the surface of the outer contact surface. Since the closure bags are manufactured by cutting off successive bags and stacking one atop another, the outer contact surfaces of the closure profiles come into contact as the closure bags are stacked and an improvement in the ease of sliding the outer closure surface of one bag over the outer closure surface of another closure bag substantially improves the manufacturing process. This improved processing of the closure bags results in increased rates of manufacture and ease of handling during the manufacturing process.

Claims (57)

The embodiments of this invention for which an exclusive property or privilege is claimed are defined as follows:

1. A closure device having opposed closure profiles having outer contact surfaces, respectively, which closure device becomes engaged when pressed together by a user's fingers when said user's fingers are slid along said outer contact surface wherein at least one of said closure profiles is characterized as having an embossed outer contact surface whereby thy embossed pattern is selected so that the Coefficient of Friction on the outer contact surface is reduced, as compared to the same outer contact surface without said embossed outer contact surface.

2. A closure device according to claim 1 wherein both closure profiles have an embossed outer contact surface.

3. A closure device according to claim 1 wherein said embossed outer surface is embossed with an embossed pattern selected to reduce the coefficient of friction of the outer contact surface of said closure profile over the coefficient of friction of the same outer contact surface sans said embossed pattern.

4. A closure device according to claim 1 wherein the closure device is an interlocking closure device.

5. A closure device according to claim 1 wherein the closure device is an adhesive closure device.

6. A closure device according to claim 1 or claim 2 or claim 3 or claim 4 or claim 5 wherein the closure device has an embossed outer contact surface characterized by a diamond pattern with between about 14 and about 56 lines in each diagonal line per inch.

7. A closure device according to claim 6 wherein the outer contact surface is characterized by between about 30 and about 40 lines per inch in each diagonal line.

8. A closure device according to claim 6 wherein the embossed outer contact surface has a diamond pattern and a grit blasted pattern.

9. A closure device according to claim 1 wherein said closure profile additionally comprises a flange portion.

10. A closure device according to claim 9 wherein said flange portion has at least one rib portion.

11. A closure device according to claim 4 wherein said closure device is a color change closure device.

12. A container comprising two flexible sidewalls and a closure device including two closure profiles operable for being engaged continuously over a predetermined length and connected to said sidewalls, wherein the improvement comprises at least one of said closure profiles having an embossed outer contact surface for reducing the coefficient of friction of the outer contact surface of the closure profile.

13. A container according to claim 12 wherein both closure profiles have an embossed outer contact surface.

14. A container according to claim 12 wherein the embossed pattern of the said embossed outer contact surface is selected to reduce the coefficient of friction of the outer contact surface of said closure profile over the coefficient of friction of the outer contact surface sans said embossed pattern.

15. A container according to claim 12 wherein said embossed pattern of said outer contact surface is on the outer contact surface of the flexible sidewall and the closure profile is adjacent the inner surface of the flexible sidewall.

16. A container according to claim 12 wherein said embossed outer contact surface is on the outer contact surface of said closure profile and said closure profile is affixed adjacent the outer surface of the flexible sidewall.

17. A container according to claim 12 comprising two flexible sidewalls and closure device having opposed interlocking closure profiles operable for being interlocked over a predetermined length which become engaged when pressed together and which become separated when drawn apart and having at least one of said opposed closure profiles having an embossed outer contact surface wherein said embossed outer contact surface is embossed with a pattern selected to reduce the coefficient of friction of the outer contact surface of said closure profile over the coefficient of friction of the outer contact surface sans said embossed pattern.

18. A container according to claim 12 or claim 14 or claim 17 wherein said container comprises closure profiles having different colors for establishing visually the completeness of the occlusion of said closure profiles.

19. A container according to claim 12 wherein the closure device is an interlocking closure device.

20. A container according to claim 12 wherein the closure device is an adhesive closure device.

21. A container according to claim 12 or claim 14 or claim 17 or claim 18 wherein the closure device has an embossed outer contact surface characterized by a diamond pattern with between about 14 and about 50 lines per inch in each diagonal line.

22. A container according to claim 21 wherein the outer contact surface characterized by between about 30 and about 40 lines per inch in each diagonal line

23. A container according to claim 21 wherein the embossed outer contact surface has a diamond pattern and a grit blasted pattern.

24. A container according to claim 12 wherein said closure profile includes a flange portion.

25. A container according to claim 24 wherein said flange portion includes at least one rib portion.

26. A container according to claim 17 wherein said closure profile includes a flange portion.

27. A container according to claim 26 wherein said closure profile includes at least one rib portion.

28. A container according to claim 12 wherein said closure device is a color change closure device.

29. A container according to claim 17 wherein said closure device is a color change closure device.

30. A container according to claim 12 wherein said sidewalls are embossed.

31. A container according to claim 17 wherein said sidewalls are embossed.

32. A container according to claim 12 wherein said container is provided with gussets.

33. A container according to claim 17 wherein said container is provided with gussets.

34. A container according to claim 12 comprising two flexible sidewalls and an interlocking closure device having two closure profiles operable for being interlocked continuously over a predetermined length and connected to the sidewalls, the closure profiles having different primary colors selected to produce a predetermined secondary color, whereby the complete occlusion of the closure profiles can be identified visually easily and wherein the closure profiles are further characterized as having at least one of said closure profiles having embossed outer contact surface for being contacted by a user of the closure profile for interlocking the two closure profiles over a predetermined length.

35. A container according to claim 34 wherein said embossed outer contact surface is characterized as having a diamond pattern with between about 14 and about 50 lines per inch in each diagonal line.

36. In a method for manufacturing a closure device comprising two closure profiles having outer contact surfaces wherein said closure profiles are extruded from a molten mass of thermoplastic material and stacked one atop another the improvement comprising having at least one of said opposed closure profiles having an embossed outer contact surface.

37. A method according to claim 36 wherein both closure profiles have an embossed outer contact surface.

38. A method according to claim 36 or claim 37 wherein said embossed outer contact surface is embossed with an embossed pattern selected to reduce the Coefficient of Friction of the outer contact surface a between two contacting closure profiles when said outer contact surfaces said closure profiles are contacted during stacking.

39. A method according to claim 36 wherein the closure device is an interlocking closure device.

40. A method according to claim 36 wherein the closure device is an adhesive closure device.

41. A method according to claim 36 or claim 37 or claim 39 or claim 40 wherein the closure device has an embossed outer contact surface characterized by a diamond pattern with between about 14 and about 56 lines per inch in each diagonal line.

42. A method according to claim 41 wherein the outer contact surface is characterized by between about 30 and about 40 lines per inch in each diagonal line.

43. A method according to claim 41 wherein the embossed outer contact surface has a diamond pattern and a grit blasted pattern.

44. A method according to claim 36 for the manufacture of a container in an in-line continuous method, said container comprising two flexible sidewalls wherein said closure device color change is an interlocking closure device including two closure profiles operable for being interlocked continuously over a predetermined length and connected to said sidewalls, said two closure profiles having an embossed outer contact surface for reducing the coefficient of friction of the outer contact surface of the closure profiles during stacking wherein the outer contact surface of one closure profile is slid over the outer contact surface of another closure profile.

45. A method according to claim 44 wherein both closure profiles have an embossed outer contact surface having a diamond pattern with a grit blasted pattern.

46. A method according to claim 36 or claim 45 wherein said embossed outer surface is selected to reduce the coefficient of friction of the outer contact surface of said closure profile as between stacked closure profiles over the coefficient of friction of the outer contact surfaces sans the embossed pattern.

47. A method according to claim 36 or claim 37 wherein said embossed outer contact surface is on the outer surface of the flexible sidewall and the closure profile is adjacent said embossed surface on the inner surface of the flexible sidewall.

48. A method according to claim 36 wherein said embossed outer contact surface is on the outer surface of the closure profile and said closure profile is adjacent the outer surface of the flexible sidewall.

49. A method according to claim 36 wherein said container comprises closure profiles having different colors for establishing visually the completeness of the occlusion of said closure profiles.

50. A method according to claim 36 or claim 37 or claim 44 wherein sand containers are formed in an in-line continuous process by successively cutting individual containers from a continuous supply of extruded container stock comprising closure profiles affixed to a flexible film material wherein each formed container is stacked atop another formed container whereby the outer contact surfaces of two formed containers are contacted during stacking as the outer contact surface of one container slides over the outer contact surface of another container.

51. A method according to claim 49 wherein the reduction in the coefficient of friction is determined by determining the coefficient of friction as between two outer contact surfaces of two closure profiles on two different containers.

52. A container according to claim 12 or claim 13 wherein the embossed outer contact surface is characterized as a grit blasted embossed pattern.

53. A container according to claim 18 wherein the embossed outer contact surface is characterized as a grit blasted embossed pattern.

54. A method according to claim 36 or claim 37 wherein the embossed outer contact surface is characterized as a grit blasted embossed pattern.

55. A method according to claim 38 wherein the embossed outer contact surface is characterized us a grit blasted embossed pattern.

56. A method for improving the ease of closure by a user of a container having a closure device comprising opposed closure profiles having of outer contact surfaces which are capable of being contacted by the fingers of said user during closure of said opposed closure profiles wherein said method comprises providing said outer contact surfaces of said opposed closure profiles with an embossed outer surface providing outer contact surfaces having a reduced Coefficient of Friction for contact with a user's fingers when such are contacted during closure with said embossed outer contact surfaces as compared to the Coefficient of Friction of the same outer contact surfaces without said embossed outer contact surfaces.

57. A stack of at least two bags wherein each bag has a closure device comprising opposed closure profiles having outer contact surfaces which are capable of being contacted by an outer contact surface of said other bag when stacked wherein said contacting outer surfaces comprise outer contact surfaces with an embossed outer surface having a reduced Coefficient of Friction for contact as between said two outer contact surfaces of said bags when such are contacted in said stack as compared to the Coefficient of Friction of the same outer contact surfaces without said embossed outer contact surfaces.