FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
COMPLETE SPECIFICATION
(See Section 10)
"An improved In-mould decoration label and the process for manufacturing the same".


PRS Solutions Private Limited, a Company incorporated under the Companies Act, 1956 and having its office at 63, Bombay Samachar Marg, Mumbai - 400 001 Maharashtra State, India, India.
The following specification particularly describes the nature of this invention and the manner in which it is to be performed.


FIELD OF THE INVENTION :
This invention relates to 'an improved in-mould decoration label' and the process of manufacturing the same. The present invention relates to an improved in-mold decorating process which is particularly well suited for the preparation of plastic components which have higher depth and three dimensional shapes such as plastic parts for automobiles.
Process for an improved in-mold decoration label which greatly simplifies the manufacture of plastic parts with graphics and/or symbols. The disclosed process is not only simpler but also produces one-piece products that are superior to the multi-component plastic assemblies which are presently available.
DESCRIPTION OF THE PRIOR-ART :
Manufacturers of automobiles are constantly looking for incorporating new features and coming out with new models to attract their customers. Decals or Graphics which have now become an essential component for any two wheeler not only distinguises different models but also enhances the asthetics of the vehicle and helps in enhancing the brand immage of the manufacturer. Traditionally, decals and graphics used by automobile manufacturers are based on screen printed adhesive coated film and are applied on pre-painted metal and/or plastic part followed by a clear lacquer coat to give higher degree of gloss. Alternately, pre-lacquered decals are supplied by decal manufacturers and are applied on painted plastic parts, thereby avoiding the post lacquering of plastic parts.

To date, plastic components of automobile parts such as side covers, seat covers of two wheelers and similar parts have been produced using complicated and/or costly manufacturing procedures. This high degree of complexity has been necessitated by the complexity of such parts, which are typically manufactured in multiple stages requiring huge painting lines and involvement of manual operations. For example, a typical side cover and/or seat cover assembly usually includes injection moulding of plastic component followed by cleaning, paint application including baking in ovens, manual application of screen printed graphics on each component individually followed by application of stoving type clear coat, when required. These separate operations not only take long time to make the final component, but also involve huge investment for large paint and clear coat lines. Further, present process of manufacturing these components require paints of different shades and clear varnishes all of which have high amount of volatile organic compounds (VOC) that are released to atmosphere during baking operations and pollute environment and is a major concern for vehicle manufacturers as they are not environment friendly operations. All these above mentioned steps make the entire process expensive, with long cycle time and require maintaining huge inventory of moulded components, paints and lacquers. To overcome post lacquering operation manufacturers are applying pre-lacquered graphics where the desired level of gloss is achieved by the decal manufacturer by applying a clear coat using screen painting technique. However, such graphics being applied on first surface (outermost layer) of the plastic part remains exposed to vandalism.
One of the most efficient and cost-effective ways of decorating a plastic part is to do it during the moulding process. When this surface effect is applied during the moulding process, it reduce time, space, material and machinery requirements. It also allows processors to supply final parts, rather than just

moulded components. This is achieved by placing a printed and formed substrate into the cavity of a mould followed by injecting molten plastic in the mould. This process is generally known as in-mould decoration (IMD). The graphic in the moulded component can either be on outside or encapsulated between the transparent film and the molten plastic. In-mould decoration techniques is known to have been used in industry for in-mould labeling of such pre-printed designs during injection moulding process for smaller parts where extent of three dimensional forming is not exceeding 14" such as cell phones, internal automotive components etc. For bigger parts and parts requiring three dimensional forming more than W such as bumpers of cars coloured films are known to have been used to decorate them during moulding. In a typical in-mould decorating process, a printed substrate is formed into a three-dimensional shape and placed into a mould. Molten resin is then injected into the mould cavity space behind the formed substrate, forming a single moulded part. The process is appropriate for parts that are not particularly complicated. However, the process must be modified in order to produce parts such as plastic parts of automobiles, which usually require multiple colored graphics to be applied in pre-determined positions and the extent of three dimensional forming is high.
SUMMARY OF INVENTION
The present invention is particularly directed to an improved method for manufacturing in-mould labels for plastic parts of motorbike or similar structures wherein one or more multi coloured graphics are screen printed onto a single film which is then incorporated with other components in an in-mold decorating process and is comprising of following steps :

(a) cutting a thick, transparent and clear plastic sheet having smooth finish on both the surfaces; (the said plastic sheet is made up of polymeric substance such as polycarbonate film)
(2) printing on one side of the said plastic sheet with graphics and/or symbols which may be of single layer or multilayer inks and/or tie coat by screen printing and/or other printing techniques on the second surface of the said film using solvent based and/or radiation curable screen printing inks where one colour is printed at a time and is followed by drying in air / oven or curing under ultra violet radiation;
(3) forming the said printed sheet into a three-dimensional shape, (such as that of an automobile seat cover, side cover, fairing etc.) by placing the said sheet over a vacuum forming tool and simultaneous application of heat on non printed side and vacuum on printed side; and
(4) trimming the said formed printed sheet by mechanical cutting or laser cutting thereby removing excess plastic and giving the printed sheet desired shape and size so that it fits inside an injection mould having a surface which matches the three dimensional shape of the formed label.
The Formed labels are supplied to customer for moulding into their components / parts by injection moulding technique. Such components/ parts may vary in design, style and shape. The sectional view of the said components / parts comprises of the following four discreet layers:
(1) a polycarbonate film layer or similar transparent substrate;
(2) a printed graphic layer which is printed on the inner surface of the
polycarbonate layer;

(3) a tie coat layer which may be either a layer of printed graphic itself or a separate coat;
(4) a polymeric substrate with suitable bond strength and it is injection moulded directly against the decorated layer and /or tie coat layer.
The present process gives many benefits to the processor of the final part. The most beneficial part is that the disclosed process eliminates the need for making individual components separately and then assembling them together. This process also helps in reducing the component cost as it eliminates the need of subsequent painting and lacquering of plastic parts. The process is environment friendly as there is no release of volatile organic compounds (VOC) associated with adhesive coating of decal substrate, painting and lacquering of plastic components. The described process further reduces the tooling costs and processing cycle time over the processes described in the prior art.
Design changes or modifications may be made simply and cost effectively with the present process, because such changes or modifications, when necessary, may be made to the screen printing rather than the injection molding or tooling equipment. This process further provides the liberty of producing different designs at the same setting by simply changing the graphics even while using the same injection moulding tool.
The disclosed process produces one-piece injection molded parts having a permanently bonded graphic(s) which is/are sandwiched between the film and the injected thermoplastic resin. Plastic parts produced by in-mould

decoration process can provide a number of advantages over other decoration methods described in prior art:
In-molded graphics can provide product differentiation for consumer
applications.
Graphics with complex designs can be incorporated as the same is achieved
by screen printing and does not require intricate punching and manual
application.
Processing and labor costs can be reduced as no application of graphic,
painting of plastic parts and/or lacquering of graphics is required.
The graphic remains in place for the life of the part and is protected from wear, abrasion and vandalism as the graphic is encapsulated between the outer layer of film and inner layer of polymeric resin.
The two most important components of any formed in-mould label are the film substrate and inks used for producing the graphic. Selection of proper film and its thickness is very important as this part of the final assembly is in contact with the environment and is subjected to abrasion, contact with cleaning reagents and ultraviolet radiations. For plastic parts which are exposed to environment and are subject to impact and abrasions the proper substrate will be a polymeric film having two surfaces, one outer surface or the first surface and the other inner surface or the second surface, and of 200 to 500 micron thickness. The polymeric film is having both surfaces clear and transparent and is made out of a polymer which has high impact resistance, good scratch resistance and is suitable for outdoor use. The most appropriate film found for such applications is polycarbonate film.

Although the graphics can be printed on either surfaces of the film, second surface printing is preferred as there are a number of drawbacks with first surface printing since the graphic is exposed to the environment, and therefore susceptible to wear. This problem is eliminated with second surface printing , where the graphic is encapsulated between film and inner plastic material. In second surface printing process graphic directly comes in contact with hot molten plastic and this sometimes results into wash out i.e. loss of adhesion between ink and the film substrate and/or fading/spreading/distortion of graphic. The second problem associated with this process may be poor adhesion between the graphic and the plastic part. Both these problems were solved in the present process by selecting high temperature withstanding inks and providing an extra ink/primer layer as the last layer or the layer which comes in contact with the molten plastic during injection moulding process the said layer being known as a tie coat. Another way the wash out can be minimized is to locate the graphic away from the gate area of the injection moulded part. This however puts lot of restriction to the designer of the component parts. The said tie coat can be one of the graphic inks itself which is cured by use of a cross linking catalyst or a primer solution containing at least one of the resins which bonds / fuses with the resin to be used for moulding. For in-mould labels described in the present invention it is important to use inks with very high elongation / flexibility to ensure minimum deformation during forming.
In the present invention the graphics were printed on the second surface of the film by screen printing technique. Screens made of polyester fabric using dimensionally exact filaments are coated with coated uniformly on both surfaces with photo sensitive emulsions and then developed against respective positives to get desired stencil. Considering the deep forming required and various contours of parts the graphic printing is restricted to the center of the

screen to avoid stretching and distortion of the graphic while forming. Fabric thread diameter, emulsion deposition, squeeze angle etc. are selected to have very thin ink deposition of each layer so as to avoid ink cracking during forming.
After each colour printing the sheets are dried in an air circulating oven when solvent based inks are used or passed through a conveyor under medium pressure mercury vapour lamp(s) when printing is done using radiation curable inks. Oven temperature and duration of drying is controlled to avoid distortion of the film.
For parts having a draw depth greater than 1/2 inch, thermoforming is a preferred technique. In order to obtain properly fitting film inserts the forming tool and the injection moulds are built using the same drawing. However, shrinkage factor of the film and the expansion factor of the mould at the operating temperature must be considered for final dimensions of the forming tool. Polycarbonate film typically shrinks about 0.5-0.9% after forming, depending on the mold. The thermal expansion properties of the mold material is subtracted from the film shrinkage number to obtain accurate mold dimensions. Forming tools for use on polycarbonate substrates are made out of hard and durable materials such as cast aluminum.
Forming process is carried out on a thermoforming machine where the forming tool is fixed below a movable frame which is used to hold the printed sheets while forming. Typically the thermoforming machine will have arrangements for heater and a blower above the film and a vacuum system below the forming tool. The printed sheets fixed to the frame are heated by the heater from the top side for a pre determined time so as to make the film soft and pliable. At this stage the forming tool is pushed through the said soft

film to give it a stretch upwards followed by application of vacuum, which brings the soft film all around the tool in a tight fitting manner. The heating is stopped and is immediately replaced by cold air blow to set the soft printed film in a rigid shape.
After the thermoforming operation the formed parts are mounted on a jig and the sides, the holes and the slots as per design aje cut out of the formed part by using a mecahanical cutter attached to a router which is PLC controlled to give the final label in the shape and size exactly fitting the injection mould cavity.
This invention describes the steps involved in the production of In-Mould Labels suitable for converting into in-Mould decorated plastic parts with three dimensional structure and having more depth such as plastic parts for automobiles etc. The said labels can be used by those skilled in the art of injection moulding to make final parts. Further, the various parameters discussed herein may be adjusted by those of skill in the art in order to maximize results.

Name of Applicant: PRS Solutions FVt. Ltd Total: One sheet
Application No: / MUM/2008
DESCRIPTION OF THE PREFERRED EMBODIMENTS:

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Polymeric clear film Screen printed graphics Tie coat

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Thermoplastic resin


(Bharat S. Shah) Duly Constituted Attorney
FIGURE 1 of 1

WE CLAIM :
1. An improved In-mould decoration label and the process for manufacturing the same comprising the steps of:
(a) cutting a thick, transparent and clear plastic sheet having smooth finish on both the surfaces;
(b) printing on one side of the said plastic sheet with graphics and/or symbols which may be of single layer or multilayer inks and/or tie coat by screen printing and/or other printing techniques on the second surface of the said film using solvent based and/or radiation curable screen printing inks where one colour is printed at a time and is followed by drying in air / oven or curing under ultra violet radiation;
(c) forming the said printed sheet into a three-dimensional shape, such as that of an automobile seat cover, side cover, fairing etc. by placing the said sheet over a vacuum forming tool and simultaneous application of heat on non printed side and vacuum on printed side; and
(d) trimming the said formed printed sheet by mechanical
cutting or laser cutting thereby removing excess plastic and
giving the printed sheet desired shape and size so that it fits
inside a injection mould having a surface which matches the
three dimensional shape of the formed label.

2. An improved In-mould decoration label and the process for manufacturing the same as claimed in claim 1 wherein the said plastic sheet is a polycarbonate film having a thickness of 0.1mm to 0.5mm, preferably of 0.2mm to 0.3mm, and is True to Form (T2FQ) grade of General Electric Company or similar grades of other manufacturers.
3. An improved In-mould decoration label and the process for manufacturing the same as claimed in claim 1 wherein the graphic is printed by screen printing technique.
4. An improved In-mould decoration label and the process for manufacturing the same as claimed in claim 1 wherein the ink used are having very high elongation/flexibility, excellent out door weather resistance and high temperature withstanding properties.
5. An improved In-mould decoration label and the process for manufacturing the same as claimed in claims 1 and 4 wherein the said inks are either solvent based or radiation curable ink and are selected from the inks available in the market,.
6. An improved In-mould decoration label and the process for
manufacturing the same as claimed in claims 1 and 3 wherein
the layer which comes in contact with the molten resin at the
time of injection moulding process is a tie coat which is printed
by screen printing technique.

7. An improved In-mould decoration label and the process for manufacturing the same as claimed in claims 1 and 6 wherein the said tie coat can be one of the graphic inks itself or a primer solution containing at least one of the resin which bonds/fuses with the resin used for injection moulding.
8. An improved In-mould decoration label and the process for manufacturing the same as claimed in claim 1 wherein the printed sheet is formed into three dimensional form by therrnoforming technique.
9. An improved In-mould decoration label and the process for manufacturing the same as claimed in claims 1 and 8 wherein the therrnoforming tool is made out of cast aluminium,

10. An improved In-mould decoration label and the process for manufacturing the same as claimed in claim 1 wherein the trimming tool used is a five axis mechanical cutter with a PLC controlled router.
11. An improved In-mould decoration label manufactured by the method as claimed in Claims 1 to 11 is obtained.
Dated this 18th day of November, 2008.
(Bharat S. Shah) Duly Constituted Attorney