Method for forming multilayer release liners and liners formed thereby

Abstract

Disclosed herein is a multilayer silicone release surface comprising a backing, a support layer on the backing, and a silicone layer of the support layer. The various layers of the multilayer release surface are deposited substantially simultaneously, as for example by a dual die or using curtain coating techniques.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a divisional of U.S. patent application Ser. No. 09 / 918,652, filed Mar. 22, 2000, which is a continuation-in-part of U.S. patent applicatin Ser. No. 09 / 389,167, filed Sep. 2, 1999, which is a continuation of U.S. patent application Ser. No. 08 / 616,859, filed Mar. 16, 1996, now issued as U.S. Pat. No. 5,962,075, which is a continuation-in-part of U.S. patent application Ser. No. 08 / 483,509, filed Jun. 7, 1995, now issued as U.S. Pat. No. 5,728,430, the entirety of each of which are incorporated by reference as if fully set forth herein.FIELD OF THE INVENTION [0002] The present invention generally relates to release surfaces of the type used with pressure-sensitive adhesive (PSA) constructions. More particularly, the present invention relates to multilayer release liners and their methods of manufacture. BACKGROUND OF THE INVENTION [0003] A pressure-sensitive adhesive construction, such as a label, generally comprises ...

AI Technical Summary

Benefits of technology

The present invention provides a method for creating multilayer release liners that are efficient and cost-effective. This is achieved by simultaneously coating a support layer and a release layer onto a substrate, which eliminates separate coating steps and saves time and money. The method also allows for precise control of the interface between the two layers, resulting in a stable and two-dimensional flow that improves the quality of the finished product. The method uses a dual die coating system that achieves a stable, two-dimensional flow by controlling the interface of the flow at its upstream most position, which is referred to as the separating streamline or separating line. This line is defined as the cross-web line where the topmost streamline of the bottom layer first meets the bottommost streamline of the top layer. The method also includes a curtain coating technique that achieves a stable, two-dimensional flow by allowing for a higher quality window for the full production coating operation. Overall, the method provides an efficient and cost-effective way to create multilayer release liners with improved properties.

Problems solved by technology

However, use of these high quality papers increases the cost of the end product adhesive construction, because such papers are typically much more expensive than regular open papers.

Growing concern over the environment has imposed stringent restrictions regarding recovery of the solvent used in applying the solvent based silicone to the high-holdout backing paper or other materials.

When applied to porous low cost papers, such as machine finished (MF) or machine glazed (MG) papers, these materials soak into the paper (penetrate the paper surface) to give ineffective coverage of the paper fibers unless excessively high quantities of expensive silicone are used.

Ineffective coverage of the paper fibers provides unsuitable release liners for PSA applications, especially where high speed convertibility is an essential performance feature.

However, there are several drawbacks to this prior art process.

First, additional costs are incurred because the prior art methods require two coating steps.

Otherwise, there is a potential for undesirable intermixing or destruction of the respective layers.

Second, because two separate coating steps are required, more time is needed for the overall formation of the release liner.

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