Coating processes – Direct application of electrical – magnetic – wave – or... – Polymerization of coating utilizing direct application of...
Reexamination Certificate
2001-04-24
2002-12-31
Pianalto, Bernard (Department: 1762)
Coating processes
Direct application of electrical, magnetic, wave, or...
Polymerization of coating utilizing direct application of...
C427S385500, C427S393500, C427S407100, C427S412100, C427S505000, C427S514000, C427S516000, C427S551000, C427S553000, C427S558000, C427S559000
Reexamination Certificate
active
06500495
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to a process of curing radiation curable inks applied to curved surfaces including spherical surfaces with ultraviolet (UV) and/or visible light and curing with electron beam. More particularly, the invention is directed to a combination of UV light and/or visible light and electron beam curing of radiation curable inks and their application to and curing upon game balls, golf balls and the like. These inks are preferentially applied as single or multiple, clear or color layers for forming logos or production prints on game balls including golf balls.
BACKGROUND OF THE INVENTION
It is often desirable to apply clear, pigmented or dyed ink coatings or layers to form distinctive logos or production prints on game balls (e.g., golf balls, ping pong balls, billiard balls, baseballs, basketballs, racquet balls, handballs, etc.). Various commercially available inks are commonly used for this purpose.
To clarify the difference between logo printing and production printing, a brief description of these processes as they are applied to game balls such as golf balls (e.g., having curved surfaces) is provided below. Golf balls are commonly one-piece, two-piece or three-piece constructions. One-piece balls are made from a homogeneous polymer shaped into a golf ball. Two-piece golf balls comprise an inner core and an outer surrounding polymeric shell. Three-piece golf balls comprise various combinations of a core (wound or unwound), one or more intermediate polymeric shells and an outer polymeric cover. The cover polymer used in two-piece and three-piece balls may, for example, be balata, an ionomeric polymer (e.g., SURLYN®) or a polyurethane.
Golf ball covers are commonly painted with a primer coat which may be colored (e.g., white) or transparent. Alternately, the cover itself may contain a colorant. Typically, a tough, often glossy, topcoat is applied over the cover and/or the primer coat to form a protective outer seal on the golf ball. The topcoat may comprise, for example, a two component urethane. The topcoat typically increases the shine (i.e., glossy appearance) of the golf ball to enhance or brighten its appearance.
As used herein, “production printing” is when ink is applied directly to the cover or to the primer coat and the ink is then further coated with a topcoat. The image produced thereby is a “production” print and the ink used for this purpose is a “production” ink. In production printing, for some applications, when ink is applied directly to a cover, the cover surface is first roughened, for example, by sandblasting to enhance the bond between the ink and the cover. Thereafter, the ink is applied to the roughened cover. A transparent water based or solvent based overcoat may be applied over the ink layer and on the roughened cover to smooth out the cover and ink surfaces. Examples of such overcoats include urethane, polyester and acrylic. Thereafter, a topcoat is preferably applied to the overcoat.
Alternatively, “logo printing” as also used herein, involves the application of the ink directly onto a topcoat. The image produced thereby is a “logo” and the ink is a logo (or custom) ink. Thus, by use of production and/or logo printing one may add decorative markings such as a company trademark, symbol or the like to increase brand recognition and/or to enhance the appearance and/or the visibility of golf balls, game balls and the like. Logo prints therefore adhere to the typically glassy exterior of a topcoat, and have no other protective coating affixed thereto.
Inks used in production and logo printing must have sufficient durability. Durability is influenced by such factors as ink layer flexibility (i.e., ink layer brittleness), ink layer resistance to abrasion, ink migration due to gravity, ink layer hardness, adhesion to golf ball cover polymers such as ionomers (e.g., SURLYN®), balata, polyurethane, polyolefin and mixtures thereof, adhesion to topcoats, adhesion to primer coats and intercoat adhesion between various layers of inks and/or other overcoats and/or topcoats.
Most commonly, logos and production prints are applied to golf balls by a pad printing process and apparatus. Pad printing uses an etched image plate (i.e., a cliche) having an etching of the desired image. The image plate, typically, is made of a tough material such as metal, steel, other alloy or photopolymer which normally has a uniform thickness except for the area defining the etched image. The plate may optionally be coated with one or more protectant layers or materials, to enhance its useful life. Typically the depth of the etched image is from about 5 microns to about 30 microns.
During pad printing, ink is applied to the image plate, thus filling the etched image. Excess ink is then scraped off of the image plate, leaving behind ink only within the etched image. A printing pad is then momentarily lowered and pressed onto the inked image plate to lift ink off of the etched ink filled cavity onto the printing pad. The ink so lifted defines the shape of the etched image. The inked pad is then momentarily lowered and pressed onto, for example, a golf ball, thereby releasing the ink from the pad to the golf ball. The ink released from the pad forms, on the spherical surface of the ball, an image corresponding to that of the etched cavity.
This process of inking the image plate, scraping off excess ink, lifting off ink onto the printing pad and releasing the ink from the pad to the object (e.g., golf ball) to be inked may be repeated to print a plurality of images on a plurality of types of balls with various inks having desirable ink properties. The process of pad printing is well known. See, for example, U.S. Pat. Nos. 5,513,567 (Froh et al.); 4,896,598 (Leech, Jr.); 4,803,922 (Denesen); 4,745,857 (Putnam et al.); and 5,237,922 (Ho).
Printing pads are made from a resilient material such as silicone rubber which desirably picks up ink from the etched cavity of the image plate during lift-off and releases all of the ink lifted off when brought into contact with the article to be printed. Once the ink is deposited, it is cured, most commonly by a thermal curing process.
However, during manufacturing of printed articles such as game balls and golf balls, ink transfer problems are often encountered. For example, while it is desirable that all of the ink picked up by the printing pad be fully released onto the article to be printed, sometimes complete release is not achieved. Consequently, subsequent articles to be printed upon by the same printing pad member may have excessive ink or misaligned ink deposited thereon. Such improper ink deposition leads to unwanted ink contamination of balls, either directly between balls or indirectly by first transferring ink to ball handling equipment or both. Resolution of such problems requires expensive positioning equipment to prevent unwanted contact between balls, between ink depositing members and balls and between ball handling equipment and balls, respectively.
To overcome such ink transfer problems, intermediate thermal curing steps are introduced into the manufacturing process. There are several disadvantages to thermal curing, however. These include (1) high energy consumption, (2) long cooling cycles, (3) restricted material selection to thermally curable and thermally stable polymeric materials and (4) use of costly ventilating systems to dissipate vapors generated during thermal curing.
In addition to the problems associated with ink transfer before the ink is cured, post manufacturing problems are also commonly encountered even after curing takes place. Ink layers, after cure, may not possess a desirable level of adhesion to a substrate article surface. For example, a logo printed onto a golf ball topcoat is subjected to repeated “hard” impacts by a golf club during the golf ball's normal useful life. If adhesion, toughness, flexibility and/or hardness are at an undesirable level, ink deposited upon a topcoat (e.g., a logo printed upon a finished ball having an underlying topcoat or a cl
Acushnet Company
Pianalto Bernard
Swidler Berlin Shereff & Friedman, LLP
LandOfFree
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