Graphic image fusion

Abstract

An in-mold and in-line decorating method is disclosed which, using a single sheet layer, allows the placement of the highest possible quality graphics into the surface of products made from a variety of moldable thermoplastic, thermoset, and vulcanizable materials using a variety of molding processes. The methods also provide new or improved capabilities for product identification, safety, and serialized tracking.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a division of U.S. patent application Ser. No. 10 / 389,831, which is a division of U.S. patent application Ser. No. 09 / 521,127, filed Mar. 7, 2000 (issued as U.S. Pat. No. 6,544,634). The application claims the benefit of U.S. provisional application Ser. No. 60 / 125,316 filed Mar. 19, 1999.BACKGROUND OF THE INVENTION [0002] The present invention is directed to creating in-mold and in-line decorated articles having higher quality than previously attainable, greater permanence than previously available, using molding techniques previously excluded, using processes and materials previously excluded, and offering improvements in yield, throughput and scrap rates. The present invention provides images of near photographic quality that are highly resistant to fading, chemicals and abrasion that can be produced using both thermoplastic and thermosetting processes. The present invention makes possible new in mold and in-line ...

AI Technical Summary

Benefits of technology

[0020] A sheet of seven mil thick PPG Industries MIST® material is printed with a four color process lithographic image using inks from the Grafusion™ series. The printed image is then coated using GRA-003 coating available from Pinnacle Products Group, Ltd., Dayton, Ohio. The sheet is then placed on the vertical cavity wall of a 30 gallon refuse container mold and held in place using electrostatic treatment. The mold is then closed and a twenty pound part is injection molded using polyolefins. The molding produces a refuse container containing a high quality durable and abrasion image molded on its side. The process demonstrates the stability of the in mold graphic on a smooth surface within the mold where a high volume of high pressure molten material must flow past the graphic to fill the mold. The process further demonstrates the effectiveness of the invention in performing in-mold graphic decoration without changes to the mold or molding equipment. The process provides the customer with a method of customizing such containers for individual communities.

[0021] A sheet of ten mil thick Daramic™ material available from Daramic, Inc., Owensboro, Ky. is printed lithographically with a four color process image using inks from the Grafusion™ series. The printed image is then coated first with GRA-C501 and then with GRA-003 coatings and is fed into the lower gap of a sheet extrusion line roll stack with its printed surface against the lower roller containing a leatherette texture and its reverse side coming in contact with a proprietary thermoplastic rubber material derived primarily from recycled truck tires. This continuously operating in-line process produces a rubber mat with a high quality image fused into its surface and a v-grooved back which is cut to the appropriate size for use as a truck mud flap. The product is then installed on a truck for in service testing where the mud flap and its image display satisfactory abrasion and fade resistance in a high stress environment for six months. The mud flap product provides the capability to carry a photographic quality image on a mud flap for advertising purposes. EXAMPLE 7

[0022] A sheet of ten mil MiST™ material has an aluminum metallized material available from Kurz-Hastings Corporation deposited thereupon using heat lamination creating an in-moldable sheet of MiST™ with an aluminum metallized surface. The sheet of metallized surface MiST™ is then placed into the cavity of an injection mold opposite the injection gate and a part is molded using polycarbonate. The resulting part is produced having a metallized and acceptably reflective permanent surface for use in the headlight assembly of a lawn tractor. The sheet of MiST™ material creates a vehicle for permanent attachment of the metallized surface to a product where said metallized surface could not otherwise be permanently attached. EXAMPLE 8

[0023] A sheet of ten mil MiST™ material is printed with a set of ten process color images using a Xerox Docutech® color laser printer and is then coated with GRA-C501. The images are then die cut from the sheet and are placed one at a time in an injection mold and a part is molded using ABS plastic. The parts that are produced contain a permanent in-molded full color image and are usable for placement on other products as a manufacturer identifying plaquard. EXAMPLE 9

[0024] A sheet of ten mil Daramic™ material is printed via offset lithography four color process using Grafusion series inks and is then screen coated using GRA-C501 coating. The sheet is then fused into the surface of rubber derived from recycled tires via a sheet extrusion process. The resulting graphic product then has adhesive reflective tape pressed onto its surface producing a graphic product with a reflective border where said reflective tape will not adhere to said rubber of said product produced without said graphic molded into its surface.

Problems solved by technology

These suffer from poor adhesion to many types of materials resulting in decorative labels that peel and degrade the appearance of the product.

The loss of labels containing safety related information is obviously a much more serious issue.

Labels on products used by small children also present a choke hazard should the labels come off.

These techniques result in the lowest quality image and are generally limited to one or two colors in relatively non-complex designs.

Both of these techniques also add complexity to the manufacturing process by adding a post-molding step wherein the article is given its graphic image.

Not only do these techniques add cost and manufacturing cycle time, but aforesaid techniques also introduce opportunities to convert a part into a quality reject if the image application is not done perfectly.

Neither adhesive labels nor post mold decorating techniques involving transfer of image or color can effectively decorate over compound curvature areas or the sides of raised areas.

Current art is essentially limited to flat or single curvature surfaces.

The graphic detail quality achievable by said techniques is limited by the environment in which said inks must remain stable and not wash out or flow with the molten polymer.

The cost of screen printing, with the requirement to separately deposit each color, results in total costs that diminish the competitiveness of in-mold decorated products made using said technique.

Causative factors include damage to the graphic image on the surface of the sheet during placement or molding, damage to the sheet itself during molding and lack of stability of the printed sheet in the mold during molding.

Said graphic image damage results primarily from the robustness of the inks and lack of protection of same from the temperatures and pressures common in said molding processes.

Said sheet damage results primarily from stretching or penetration of said sheet during molding due to the pressures of molding and the flow of molten materials over the sheets to their edges.

Said lack of stability involves the movement of said printed sheet within the mold due primarily to the flow of molten material over said sheet causing said sheet to slide with respect to the mold surface or to lift from said mold surface.

Said sliding results from insufficient coefficient of friction between said sheet and said mold surface.

Problems inherent in using said electrostatic charge techniques include the inability to maintain said charge at a high enough level and for a long enough period to properly complete the molding process.

Other techniques such as described in U.S. Pat. Nos. 4,418,033 and 4,369,157 require a continuous strip of in-mold decorating material to be repeatedly advanced between each mold closure; this routinely introduces errors in alignment of the image to the part resulting in a quality reject.

Where the use of dissimilar materials is disclosed there are complex techniques, such as multi-layering, required to affect the molding.

The current state of the art offers no techniques for in-mold decorating with lithographically printed images using high stress manufacturing techniques such as injection molding.

The current state of the art offers no techniques for introduction of a three dimensional graphic into the cavity of a mold to produce a dimensional part decorated in the mold with graphics on all top and side surfaces.

Since most polymeric materials undergo shrinkage during post-molding cooling, there are issues with in-mold decorating techniques not matching the shrink rate; the current state of the art does not offer techniques for in-mold decorating where the image will automatically exhibit the same shrink rate as the polymer into which it is molded.