Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1999-09-30
2002-07-09
Seidleck, James J. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S179000, C525S180000, C525S166000, C525S185000, C525S199000, C525S240000, C525S241000, C428S040700, C428S351000, C428S352000, C428S353000
Reexamination Certificate
active
06417284
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an improved fluoropolymer coating with a new adhesion priming composition.
BACKGROUND OF THE INVENTION
Fluorocarbon coatings are widely used by industry to provide a low surface energy, solvent resistance and heat resistance properties. Examples of such coatings include PTFE, FEP, PFA (or Kalrez™), Nafion™, and Telflon™, etc. Due to the inherent non-stick property of the fluorocarbonpolymer, the coating mixture requires organic polymer binders, such as polyamide-imide. Various commercially coating mixtures are available for coating on variety of substrates, especially metal or plastics. An important such fluoropolymer coating applications is in the area of color proofing lamination applications.
Prepress color proofing is a procedure that is used by the printing industry for creating representative images of printed material to check for color balance and other important image quality control parameters, without the high cost and time that is required to actually produce printing plates and set up a printing press to produce an example of an intended image. These intended images may require several corrections and may be reproduced several times to satisfy or meet the requirements of the customers, resulting in a large loss of profits and ultimately higher costs to the customer.
Generally speaking, color proofs sometimes called “off press” proofs or prepress proofs, are one of three types: namely (1) a color overlay that employs an image on a separate base for each color; (2) a single integral sheet process in which the separate color images are transferred by lamination onto a single base; and (3) a digital method in which the images are produced directly onto or transferred by lamination onto a single base from digital data.
In one typical process for a prepress color proofing system used in the printing industry, a multicolor original is separated into individual transparencies, called color separations, the three subtractive primaries and black. Typically a color scanner is used to create the color separations and in some instances more than four-color separations are used. The color separations are then used to create a color proof sometimes called an “off press” proof or prepress proof as described above.
A KODAK Color Proofing Laminator can be used to bond lamination sheets to receiver stock as a part of a color proofing system. The lamination sheets include a carrier and a layer of material to be applied to the receiver stock, which, in the case of the Kodak Color Proofing Laminator, is a color donor. A lamination sheet is laid upon the receiver stock with the color donor side sandwiched between the carrier and the receiver stock forming a lamination sandwich.
FIG. 1 in U.S. Pat. No. 5,478,434 shows a laminator 12. As shown in that FIG. 1, a lamination sandwich 10 sits on an entrance table 20. A leading edge of lamination sandwich 10 is fed into a laminator 12 that includes an upper heated pressure roller and a lower heated pressure roller. Lamination sandwich 10 passes completely through the upper heated pressure roller and the lower heated pressure roller. Lamination sandwich 10 thereafter exits the upper heated pressure roller and the lower heated pressure roller and comes to rest on an exit table 14 undisturbed until the trailing edge is cool to the touch; whereupon the top-most carrier can be peeled away from receiver stock and from the transferred color donor. With the configuration of an upper heated pressure roller and a lower heated pressure roller as described above, the laminator is called a straight-through laminator. Further details of this type of lamination/de-lamination system can be found in the above. As an additional reference, U.S. Pat. No. 5,203,942 describes a lamination/delamination system as applied to a drum laminator.
U.S. patent application Ser. No. 09/1 33,243 filed Aug. 13, 1998, now abandoned, provides for belt roller arrangement which applies a tapering pressure to a lamination sandwich (hereinafter referred to as media to be laminated), and conveys the media to be laminated to a nip portion between heated pressure rollers. The belt materials used are either metal or thermoplastics. In addition, the belts need to survive cycled heat and pressures and preferably, to be seamless polyimide belts. However, the high surface energy of the polyimide belts pickup dirt, dusts or contamination from the media. The polyimide belt failed to release the media during usage. There is a need for an overcoat with desired heat resistance and release properties.
One commercially available polymer for lamination belt overcoat is polytetrafluoroethylene (PTFE) from Whitford. This overcoat provides a low surface energy surface to help release the media. However, within few hours of heating and pressure under normal usage, a white flake built up on the surface and image artifacts occurred. Also, a noticeable loss of release properties was observed. It is believed the PTFE could not hold within the overcoat. There is a need for an additive to reinforce the integrity of this type fluoropolymer overcoat.
SUMMARY OF THE INVENTION
In accordance with the present invention, a priming composition useful for reinforcing a low surface energy layer containing a crystalline, semicrystalline, or amorphous fluorocarbon polymeric material to a metallic or an organic polymeric substrate comprises about 98 to 99.9 weight percent of the coating mixture and about 0.1 to 2 weight percent of a perfluoroalkylsubstituted fluororesin-reactive compound.
The perfluoroalkylsubstituted fluororesin-reactive compound has the formula
where R
5
is H or F, Q is OH or SiR
6
R
7
R
8
; R
6
, R
7
, and R
8
being independently selected from the group consisting of Cl, OH, an alkyl group containing 1 to about 4 carbon atoms, an alkoxy group containing 1 to about 4 carbon atoms, an acyloxy group containing 2 to about 4 carbon atoms, and an amino group containing 0 to about 4 carbon atoms; and n is an integer from 1 to about 15; with the proviso that, at least one of R
6
, R
7
, and R
8
is Cl, OH, or an alkoxy, acyloxy, or amino group.
Also in accordance with the present invention, a substrate to which a surface layer comprises a crystalline, semi-crystalline, or amorphous fluorocarbon polymeric material. The substrate comprises metal, woods, glass or
organic polymeric materials in the shape of a cylinder or, preferably, a seamless belt. The metal substrate can be steel, nickel, aluminum, copper and zinc, etc. The polymeric substrate can be either thermoplastics or thermosets.
The organic polymer binder which incorporated with the fluoropolymer can be selected from the group consisting of a polyester, a polycarbonate, a polyimide, a polyamide, a polyamide-imide, a fluorocarbon elastomer, a siloxane silicone rubber, ethylene-propylene rubber (EPR), a polyurethane, a polystylene-co-elastomer block copolymer. The preferred organic polymer binder is from polyamides, polyimides, polyamide-imides and mixtures of them.
The additive in the present invention interacts with both the polar organic polymer binder and the fluorocarbon polymers. It also improves the binding between the fluorocarbon polymers and the substrate due to the dual functionality of the additive. The coating with the present invention is characterised by good release and excellent integrity of the overcoat during the life of the coated parts.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention, the overcoat composition can be used on various substrates for release, solvent resistance and heat resistance properties. The substrate can be metal, glass, wood, thermoplastic or thermoset resins, e.g. polyurethane, polyimide, polyamide, polyamide-imide, polyester, polyethylene, polycarbonate, silicone rubber, etc. The preferred substrate is polyimide, in the form of tube or belt. An important advantage of a polyimide as a substrate for the coated belt is that it can be fabricated as a seamless belt, thus avoiding the disadvantage of belts having seams for color
Chen Jiann-Hsing
Cody Craig M.
Lancaster Robert A.
Pavlisko Joseph A.
Tan Biao
Bissett Melanie
NexPress Solutions LLC
Seidleck James J.
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