FORM-2
THE PATENT ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003
PROVISIONAL SPECIFICATION
(See section 10 and Rule 13)
METALLIZED AND COLOURED HIGH BARRIER LAMINATES
BILCARE LIMITED
An Indian Company
of 1028, Shiroli, Rajgumnagar, (Taluka Khed),
Pune-410 505, Maharashtra, India
THE FOLLOWING SPECIFICATION DESCRIBES THE INVENTION

The present invention relates to metallized and colored high barrier laminates and a method of their manufacture. The colored laminates of this invention have superior strength properties suitable for cold forming purposes, together with excellent moisture and gas barrier properties.
A typical aluminum based laminate used in packaging of food and pharmaceutical preparations has an intermediate aluminium layer sandwiched between a PVC (polyvinyl chloride) plastic and a nylon layer. These types of laminates are often known as, hereinafter referred to as, alu-alu laminates. The PVC side is in direct contact with the packaged article and is also called as sealing side. The nylon side is the outer side. It is highly desired that the nylon side directly faces the customers and can be modified to accommodate several functional features such as for example, colors. Laminates having colored nylon side can help customers identify the appropriate package based on the color. However, because of inert properties of nylon, it is very difficult to add or apply color coats on the nylon side.
The inventors of the present invention have comprehensively and successfully investigated the possibilities of developing nylon based high-barrier laminates with colored nylon side and have surprisingly developed such colored laminates.
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Accordingly, this invention provides alu-alu laminates characterized in that the nylon is further coated with a coloring film. The present invention also provides a method of manufacture for such colored alu-alu laminates comprising
(a) Applying suitable adhesive on the nylon surface;
(b) Partial drying the adhesive coat in at an preferably at an elevated temperature; and
(c) Pressing with a colored film
The manufacturing process for the laminates of this invention comprises application of suitable adhesive coat on the nylon layer. The wet adhesive coat is partially dried, preferably at elevated temperature, to remove any volatile compounds and then pressed with a color film. The colored film that can be used include, without limitation, those commercially available. Often these color films are in the form a thin PVC films metallized with suitable metal using known techniques such as, for example, vacuum metalization. Such metallized films are then coated with suitable lacquers to achieve the desired color. Such color films can be cured, if desired, depending on the expected properties.
The laminates according to this invention have excellent strength and barrier properties. Notably, the laminates of this invention have high abrasion resistance and also can withstand cold-forming processes effectively.
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Although the current invention is described herein with specific reference to Nylon/foil/PVC based materials, several other such materials can also be advantageously used.
Representative Example
A commercially available alu-alu laminate having aluminium layer (about 45 microns) sandwiched between a PVC layer (about 60 microns) and a nylon layer (about 25 microns) was used as a base material in this example. The nylon side of this laminate was applied with adhesive coating and partially dried at a temperature of about 70°C. A 25 micron thick gold PVC film was then pressed on the partially dried adhesive layer. The resulting material obtained after drying and curing for 24 hours had the following properties. Representative analytical results:
1. Color & Appearance: No Visual defects
2. Scotch Tape test: Good Bonding
3. Adhesion Bond Strength: Min. 0.45 kg/cm
4. The film also withstood cold forming process without any rupture.
While considerable emphasis has been placed herein on the specific structure of the preferred embodiment, it will be appreciated that many modifications can be made in the preferred embodiment without departing from the principles of the invention.
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These and other changes in the preferred embodiment as well as other embodiments of the present invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.
Dated this 4th day of August 2006

Mohan Dewan
Of R. K. Dewan & Co
Applicant's Patent Attorneys
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