Stock material or miscellaneous articles – Structurally defined web or sheet – Discontinuous or differential coating – impregnation or bond
Reexamination Certificate
2000-08-01
2003-06-24
Jones, Deborah (Department: 1775)
Stock material or miscellaneous articles
Structurally defined web or sheet
Discontinuous or differential coating, impregnation or bond
C428S206000, C428S426000, C428S432000, C235S462010
Reexamination Certificate
active
06582805
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to composite labels useable at high temperatures (e.g., temperatures above about 400° C). More particularly, the present invention relates to high temperature composite labels in which the label body includes a glassy phase and a refractory phase, and in which an optically discernible code pattern is, or can be, formed in a label top layer.
BACKGROUND OF THE INVENTION
Parts and products can be tracked during manufacturing and marketing operations in order to facilitate commodity distribution, customizing product features, process control, stock control, sales control, quality control, and the like. Such tracking requires some means for marking or labeling parts and products so that such parts and products can be readily and accurately identified during tracking. For example, according to one approach, a label bearing identification information in human readable form (e.g., alphanumeric information) or machine readable form (e.g., bar code information), or both, is attached to parts running on a production line. The label is read at one or more process stations so that specific operation steps can be carried out according to work schedules corresponding to the identification information.
In some industries, printed paper labels are used for tracking purposes. However, for other industries, (e.g., steel making industries and cathode ray tube industries) production lines operate at temperatures well above ambient conditions (e.g., above 250° C., or even above 400° C.). For example, the manufacture of a glass cathode ray tube typically involves temperatures in the range from about 400° C. to about 1000° C. Paper labels do not survive at these temperatures. Consequently, labels that can be easily attached to parts and maintain their integrity at such temperatures are needed.
Many parts have nonplanar surfaces to which a label is attached in order for such parts to be tracked. For example, a cathode ray tube includes a glass cone component and a glass faceplate component, both of which have curved, nonplanar surfaces. Consequently, not only is there a need for temperature resistant labels, but there is also a need for temperature resistant labels which are conformable to nonplanar substrates at application temperatures.
Another concern relates to the durability of labels. It is most desirable if a label is durable enough to survive the entire production process without requiring interim replacement. Unfortunately, many of the previously known labels adapted for high temperatures become disfigured and/or unreadable too easily and must be replaced several times during production in order to preserve tracking capabilities. Other labels, although durable, have a tendency to delaminate and fall off of their substrates. Consequently, labels with both excellent durability and tenacious bonding characteristics would be desirable.
As a practical matter, production yields seldom reach or are maintained at 100%. For example, parts can break, fail to meet specifications, or suffer from other defects that necessitate discarding or recycling of the parts. Recycling is often more desirable than discarding bad parts, particularly when the raw materials incorporated into the parts are relatively expensive. However, before recycled materials can be returned to the production line, contaminants are preferably removed to maintain the quality of parts formed from recycled material. Unfortunately, many of the previously known labels would contaminate the recycled supply and must be removed. Labels comprising heavy metal atoms such as Pb, Hg, As, Co and Cr(VI), whether present in pure form or in the form of oxides, are of particular concern due to the toxicity associated with such materials. Oxides of heavy metals such as Pb, Cd, Hg, and/or As are known to be incorporated into glassy phases as one approach for achieving low softening points (e.g., softening points below about 350° C.). Oxides of heavy metals such as Co and Cr are known to be used for providing black color. Consequently, articles having a label comprising one or more these heavy metals are typically recycled by delabeling and separating the less desirable heavy metals containing labels from the articles. These steps can be costly and/or extremely difficult, particularly if the bond between the article and the label is especially tenacious. In addition, heavy metals may be dispersed in air when the labels containing such metals are heated to high temperatures. Accordingly, it would be desirable to provide a label substantially free of these heavy metal atoms.
SUMMARY OF THE INVENTION
In one aspect, the present invention provides a composite material (typically a ceramic composite) suitable for labeling a substrate, comprising:
(a) a fired ceramic body comprising a base layer, the base layer including:
(i) a first glassy phase;
(ii) a first refractory phase (preferably a ceramic material such as particulate ceramic material) interspersed with the first glassy phase,
the first glassy phase being capable of wetting a substrate at an application temperature; and
(b) a top layer provided on the fired ceramic body,
wherein there is sufficient color contrast between the top layer and the fired ceramic body such that a code pattern (preferably formed by selectively removing the top layer from portions of the composite layer) is optically discernible. Optionally, a label according to the present invention may further comprise a translucent (including transparent or clear) cover (e.g., a protective layer or a coating) over the top layer. A protective layer (e.g., a glass layer) is sufficiently translucent to allow a bar code reader, human eye, or other detector means to view or read the underlying code pattern. Optionally, the translucent layer(s) is a fugitive material.
Embodiments of labels according to the present invention are capable of retaining not only their dimensional integrity, but also the integrity of information incorporated into the labels, especially when the label is exposed to high temperatures (e.g., temperatures above 250° C., preferably 400° C. to 1000° C.). In another aspect, labels according to the present invention can be conveniently applied to a wide range of substrates, including metal, glass, ceramics, and the like, which are intended to be used at relatively high temperatures.
Labels according to the present invention comprise a top layer of one color overlying a layer of a contrasting color. When portions of the top layer are selectively removed to expose portions of the underlying layer, the color contrast between layers allows the resultant pattern formed from the top layer to be optically discernible. This allows information to be incorporated into the label by selectively patterning or removing the top layer to form one or more symbols of a code pattern either as a negative or a positive image, as desired. Such a code pattern, in turn, allows a labeled substrate to be easily identified and tracked during production. The code pattern(s) can be formed in the label either before and/or after the label is attached to a corresponding substrate. Information can be incorporated into the label one or more times during the service life of the label as well. This is particularly advantageous for production operations in which updating label information during the course of production is desired.
The code pattern incorporated into the label may be human readable, machine readable, combinations of these, and the like. In preferred embodiments, the code pattern includes human readable alphanumeric characters, machine readable bar code characters, or combinations thereof. Bar code patterns, in particular, can be easily and rapidly formed in labels of the present invention using, for example, well known laser ablating techniques.
Because of the color contrast and multilayer construction of labels according to the present invention, code patterns can be formed by abrasion, etching or abrading techniques in which substantially only portions of the top layer are removed. In other w
Lacave Daniel
Moh Kyung H.
Sueoss Bernardus M.
3M Innovative Properties Company
Allen Gregory D.
Jones Deborah
Stein Stephen
LandOfFree
Multilayer, temperature resistant, composite label does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Multilayer, temperature resistant, composite label, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multilayer, temperature resistant, composite label will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3087395