Title of Invention	PAPER BASED LIDDING MATERIAL FOR BLISTER PACKS
Abstract	The present invention provides a novel and cheaper lidding material for blister pack comprising a paper layer coated with at least one barrier coat and a heat sealing coat on one side and an optical lacquer coat on the other side.

Full Text

FORM-2 THE PATENT ACT, 1970 (39 of 1970) & THE PATENT RULES, 2003 PROVISIONAL SPECIFICATION (See section 10 and Rule 13) PAPER-BASED LIDDING MATERIAL FOR BLISTER PACK BILCARE LIMITED An Indian Company of 1028, Shiroli, Rajgurunagar,(Taluka Khed), Pune-410 505, Maharashtra, India THE FOLLOWING SPECIFICATION DESCRIBES THE INVENTION The present invention relates to paper-based lidding materials for use in blister pack and their method of manufacture. The lidding materials of this invention have superior tear strength, tensile strength, heat seal strength and bursting strength together with excellent moisture and gas barrier properties. The materials of this invention can be used as a low cost alternative to conventional aluminum based lidding foils without compromising on the desired strength and barrier properties. Blister packing is a common form of packaging used for a wide variety of products such as food articles, pharmaceutical preparations, toys. Blister packing is safe and easy to use and can allow the consumer to see the contents without opening the pack when at least one surface is made of a transparent material such as PVC plastic. The commonly available blister pack has two surfaces. One surface has cavities at predetermined places to hold the desired article and the other surface acts as a lid. During the process of packaging, the article to be packed is put into the cavity and the lidding material in the form of, for example a foil, is attached/fixed over the open surface of the cavity. To take the article out of the cavity, the lidding material may be burst opened or torn in a suitable fashion to release the article off. Depending on the specific requirements, a variety of modifications may be possible, especially with respect to the materials and releasing mechanisms used to arrive at a suitable blister pack. The most commonly used materials for forming blister are polymer based such as PVC (poly vinyl chloride) plastics. Depending on the material used and its thickness, such blisters are transparent, semi-transparent or opaque. Often, paper or aluminum foils are used as lidding materials. One side of the lidding material is also used for printing product information and usage instructions. The lidding material is fixed to the surface having cavities through a heat-sealing mechanism or just by application of 2 adhesive. Completely paper-based lidding material is suitable for articles that are insensitive to moisture or surrounding environment, such as plastic toys. However, purely paper-based lidding materials do not have enough strength and barrier properties required for packaging of articles that are sensitive to environment such as food items, pharmaceutical preparations. Such sensitive articles are often packed in blisters that use aluminium foil as lidding materials, due to higher barrier properties of the aluminium foil. Economic reasons, require alternative lidding matter that have strength and barrier properties comparable to aluminium foils but are cheaper than currently used aluminum foils. The inventors of the present invention have comprehensively and successfully investigated the possibilities of developing such highly desired cheaper lidding materials and have surprisingly developed such paper-based lidding materials for blister pack having excellent strength and barrier properties. Accordingly, this invention provides a paper-based lidding material for blister pack comprising a paper layer having an inner surface of paper (surface facing the cavity) coated with a barrier coat and a sealing coat and the opposite surface (outer surface) optionally coated with lacquer suitable for obtaining a printable surface. Thus, the lidding materials according to this invention comprise a paper layer sandwiched between, on one side a barrier coat and sealing coat, and on the other side an optional lacquer coat suitable for printing. 3 Brief Description of the accompanying drawing: The invention will be described in detail with reference to a preferred embodiment. Reference to this embodiment does not limit the scope of this invention. In the accompanying drawing: Figure 1 illustrates a partial sectional view of a typical paper-based lidding material according to this invention. The paper in the paper layer is selected on the basis of desired packaging requirements. A normal paper can also be used, if desired. However, such fibrous papers may have higher absorption properties and take more amounts of coating material to achieve uniform coating. One way to overcome these absorption related problems is to pre-treat the paper (for example, say waxing) to saturate and thereby lower the absorption capacity. A preferable example of paper that can be used to prepare paper-based lidding materials according to this invention is Glassine paper, also sometimes known as a Butter paper or a Tracing paper. A Glassine paper is a pure cellulose paper manufactured from 100% (fresh) cellulose and the transparency and grease resistance of such paper is achieved by a special mechanical treatment and not by chemical additives. The Glassine paper thus does not contain chemicals or other materials and has very good strength and low absorption ability. A range of Glassine paper is available commercially depending on the processing method and other properties such colors. The Glassine paper available may be used as it is or may be treated further if desired. It is desired the Glassine paper used to have a purity of at least 90%. The thickness of the Glassine paper may vary depending on the specific requirement. 4 However, Glassine paper having thickness of about 150 gsm or below are preferred. Typically commercially available Glassine paper is used.One surface of the paper will face the cavity (hereinafter referred to as inner surface) where as the other surface will act as an outer surface. The outer surface is available for printing, if desired. To the inner surface facing the packaged article (and cavity) is applied a suitable barrier coat and a sealing coat. The barrier coat imparts barrier properties to the lidding material. A wide variety of barrier coats are available commercially and can be advantageously used. Typical examples of such commercially barrier coats include, without any limitation, Diofan® and Ixan® (available from Solvay S.A.) and Serfene™ (available from Rohm Haas). A wide variety of other barrier coats capable of achieving desired barrier properties might also be advantageously used. The thickness of the barrier coat is not a real parameter and can vary according to the coating used and the barrier properties desired. Multiple barrier coats may also be applied if desired, instead of a single coat. Once the desired barrier coating is achieved, the next step is to apply a sealing coat. The sealing coat contains materials capable of attaching or fixing itself with the sheet bearing cavities. Simplest examples of sealing coats include adhesive coats or heat-sealing coats. A variety of commercially available sealing coats, including without limitation, for example Adcote™ (available from Rohm Hass) may be used. Alternatively, any other coat capable of achieving sealing, can also be advantageously used. 5 The outer layer of the lidding material according to this invention is exposed to environment and is also available for printing product information and usage instructions. The outer surface may therefore, optionally be applied with a coat capable of making itself available for printing. Depending on the properties desired, this coat may contain color pigments, stabilizes, enhancers and alike. The outer surface, optionally, may also be applied with other laminating coat(s) if desired. The thickness of paper layer, barrier coat, the sealing coat and the optional outer coat can vary depending upon the specific properties desired. Any of the above coating operations can be accomplished using known techniques and without applying any pretreatments such as application of a primer. However, one can include such pre-treatment or post-treatment operations if desired. Similarly, one may advantageously use post-treatments such as heating, annealing or curing if desired, depending on the specific needs. The lidding materials according to this invention have excellent strength and barrier properties can be used for packaging of several materials. However, the lidding materials according to this invention are particularly useful in the packaging of environment sensitive materials such as food items, pharmaceutical preparations, clinical materials and light-sensitive articles. Representative Example A Glassine paper (40 gsm) was first coated with PVdC barrier coat to achieve a barrier coating thickness of 12 + 1.5 gsm. The barrier coat was then applied with a locally available vinyl chloride monomer based heat-sealing coat (4 to 6 gsm). The outer layer of the paper was applied with 6 peariized silver based lacquer coating (1.5 ± 0.5 gsm). The resulting lidding material, after drying, had the following properties: Representative analytical results: 1. Average WVTR @ 90% Rh and 38°C: 5.97 gm/m2/24hr 2. Longitudinal Tensile Strength: 808 kg/cm2 3. Transverse Tensile Strength: 350 kg/cm2 4. Toxicity (USP): Non toxic While considerable emphasis has been placed herein on the specific structure of the preferred embodiment, it will be appreciated that many alterations can be made and that many modifications can be made in the preferred embodiment without departing from the principles of the invention. 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 IVJphan Dewan ofR.K.Dewan&Co. Applicant's Patent Attorney

Documents:

1239-MUM-2006-ABSTRACT(21-9-2012).pdf

1239-mum-2006-abstract(3-8-2007).pdf

1239-mum-2006-claims(3-8-2007).pdf

1239-MUM-2006-CLAIMS(AMENDED)-(21-9-2012).pdf

1239-MUM-2006-CLAIMS(MARKED COPY)-(21-9-2012).pdf

1239-MUM-2006-Claims-051214.pdf

1239-mum-2006-corresondence received.pdf

1239-MUM-2006-CORRESPONDENCE(28-1-2014).pdf

1239-mum-2006-correspondence(5-5-2008).pdf

1239-MUM-2006-CORRESPONDENCE(6-12-2013).pdf

1239-mum-2006-description (provisional).pdf

1239-mum-2006-description(complete)-(3-8-2007).pdf

1239-mum-2006-drawing(3-8-2007).pdf

1239-mum-2006-drawing.pdf

1239-mum-2006-form 18(6-5-2008).pdf

1239-mum-2006-form 2(3-8-2007).pdf

1239-mum-2006-form 2(title page)-(complete)-(3-8-2007).pdf

1239-MUM-2006-FORM 26(21-9-2012).pdf

1239-mum-2006-form 5(3-8-2007).pdf

1239-mum-2006-form-1.pdf

1239-mum-2006-form-2.doc

1239-mum-2006-form-2.pdf

1239-mum-2006-form-3.pdf

1239-MUM-2006-MARKED COPY(5-12-2014).pdf

1239-MUM-2006-OTHERS-051214.pdf

1239-MUM-2006-REPLY TO EXAMINATION REPORT(21-9-2012).pdf