Patent Application
20110083799
1. Field of the Disclosure
The present disclosure pertains to the attaching of a polyethylene zipper profile, or other polyethylene component, to a polylactic acid (PLA) film or other substrate.
2. Description of the Prior Art
Polylactic acid (PLA) films are relatively new, and have been commercialized within the last several years. However, attempts at attaching a polyethylene zipper profile, or other polyethylene component, to a polylactic acid film, whether by extruding the profile or component onto the film or by heat sealing a pre-made zipper to the film, have been unsuccessful due to the incompatibility between the polyethylene and PLA materials.
The use of conventional polyethylene zipper profiles is desired in order to retain the high desirable reclosability characteristics of polyethylene zipper profiles, without the necessity of developing polylactic acid zipper profiles.
It is therefore an object of the present disclosure to provide a method for the attaching a polyethylene zipper profile, or other polyethylene component, to a polylactic acid film.
This and other objects are obtained by providing extruding a functionalized polyolefin onto the polylactic acid film or substrate and then extruding the polyethylene zipper onto the functionalized polyolefin layer.
Further objects and advantages of the invention will become apparent from the following description and from the accompanying drawing, wherein:
Referring now to the drawings in detail wherein like numerals indicate like elements throughout the several views, one sees that
Complementary, male and female zipper profiles 16, 18, with respective bases 17, 19, are formed from polyethylene, typically low density polyethylene (known in the art as “LDPE”) but may likewise be formed from materials including, but not limited to, high density polyethylene, medium density polyethylene, linear low density polyethylene, metallocene linear low density polyethylene (all of which are terms known in the art), or blends thereof, or even polypropylene. The male and female zipper profiles 16, 18 are extruded (typically subsequent to any extruding of the areas 12, 14 of functionalized polyolefin) or otherwise joined to areas 12, 14 of functionalized polyolefin. The areas 12, 14 of functionalized polyolefin serve as intermediate or tie layers thereby allowing the attachment of the bases 17, 19 of polyethylene zipper profiles 16, 18 to the structure of
In general, functionalized polyolefins may be defined as polyolefins which have been functionalized to include at least one epoxy, anhydride or acid functional group, this functional group being introduced by grafting or by copolymerization. Examples of functionalized polyolefins which have been found to be particularly advantageous for this disclosure are Admer SE800 from Mitsui or Bynel products from DuPont.
Further, as shown in
In these examples, the film 10 is typically subsequently folded so as to align male and female zipper profiles 16, 18, and to allow the interlocking thereof. However, in other applications, male and female zipper profiles 16, 18 may be attached to separate films and brought together as is required for the specific application.
Thus the several aforementioned objects and advantages are most effectively attained. Although preferred embodiments of the invention have been disclosed and described in detail herein, it should be understood that this invention is in no sense limited thereby and its scope is to be determined by that of the appended claims.
This application claims priority under 35 U.S.C. §119(e) of U.S. provisional application Ser. No. 61/249,868 filed Oct. 8, 2009, the disclosure of which is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61249868 | Oct 2009 | US |
