Patent Application
20080178988
The present invention relates to a method of labelling vials and containers for storing in freezing or cryogenic environment. More specifically, it relates to labelling of vials and other containers which have a low surface temperature such as found in vials or containers freshly removed from a freezing or cryogenic environment.
It is routine practice in biotechnology and biomedical laboratories to store cell lines, DNA libraries, tissues, viruses, bacteria, fungi and other biological specimens and biochemical agents in cryogenic and freezing environments for the purpose of better preservation for extended periods of time (up to 15-20 years or more). In the biomedical and biotechnology fields, proper and secure labelling and identification of containers and objects carrying these types of biological substances are pivotal for daily research and clinical operations. Other industries also require labelling of frozen surfaces such as shelves and objects in commercial freezer.
Presently there are cryogenic pressure-sensitive labels available which can be printed with thermal-transfer printers and are offered by a number of companies (for example, GA International Inc. and others). Thermoplastic labels for cryogenic storage containers which can be inscribed by various writing instruments and/or printed in laser printers are offered by GA International Inc., and others and are described, for example, in U.S. Pat. No. 5,836,618 ('618) or No. 7,108,909 ('909). One of the issues associated with cryogenic pressure-sensitive labels is that they are not effective when applied onto frozen surfaces, for example, vials, boxes, cans or other containers. It is a well known fact that pressure-sensitive labels do not adhere well to cold surfaces. Cryogenic labels described in '618 or '909, such as 3M label material 7604FP in manufacturer's datasheet, specify that “Low temperature surfaces, below 50° F. (10° C.), cause adhesive to become firm and will not allow to develop intimate adhesive contact”. Even the efforts to wipe off the condensation prior applying the label do not allow proper label adhesion. As a result, the labels do not adhere to frozen container and detach immediately or shortly after the adhesion. As for permanent markers used to identify boxes, the wet surface, ice build-up and cold temperature in combination or individually often do not allow the ink from permanent marker to flow easily and properly bond with the surface, which results fuzzy and non-homogeneous markings which very often can be wiped off.
It is therefore an aim of the present invention to provide an identification method that addresses issues associated with the prior art.
Therefore, in accordance with the present invention, there is provided a method of labelling frozen vials and containers with a preheated label. The term label can also mean tape.
Additionally, in accordance with the present invention, there is provided a label-dispensing device for heating the labels prior the application to a frozen vial or container.
Very often it is required to label or relabel vials and other containers which are already stored in cryogenic or freezer environment such as liquid or vapour phase liquid nitrogen, freezer, dry ice, Alcohol-dry-ice bath and other low-temperature conditions when the container has a surface temperature around 0° C. or below, or even more preferably −15° C. or below, or even more preferably −70° C. or below, or even more preferably −80° C. or below and even more preferably −100° C. or below, or even more preferably −196° C. or below. For a long time, this problem has not been solved. The answer to the problem was discovered by increasing the temperature of the adhesive at the contact point with a frozen surface of the vial or other container. When an adhesive label is applied to a container there is a temperature equilibration taking place between the label and the container. When both are at room temperature, around 18-22° C., the temperature of the adhesive remains the same as the temperature of the containers surface which allows an adequate flow of the adhesive from the label to the container and adequate bonding. When the same label at room temperature is applied to a container following its removal from a freezing or cryogenic environment e.g., −70° C., the equilibration between temperatures on the contact will take place between the adhesive-coated label and the container. Since the mass of the container in most cases is significantly larger than the mass of the label, the equilibration will yield a significant temperature drop for the adhesive and the label whereas the temperature of the container will stay relatively the same. In the case when the vial or container is at room temperature, then the temperature of the adhesive is sufficient to support the adequate flow of the adhesive and appropriate bonding. But when the temperature of adhesive drops during the contact with the frozen container the adhesive gets hardened and consequently cannot flow and form an adequate bond. Based on the model developed, the solution was found by increasing the temperature of the adhesive label at the moment of application to the frozen vial or container such as preheating the label prior applying to the frozen container. Our tests showed that when the adhesive temperature is around 60-70° during the contact with frozen surface, the equilibration yields some brief increase of the temperature of the contact surface of the vial or container which is sufficient to permit for a very short time the adequate flow of the adhesive and its bonding with a vial or container. After the bonding is taken place, the temperature of the adhesive and the label components will drop but it will not affect the adhesion since the label is firmly bound to the container through the adhesive.
So, a theory is developed that adhesion of a label to a frozen surface can be enforced by a brief increase of the temperature at the contact point between the adhesive and container.
Based on the theory a new method of cryogenic labelling is developed involving the following steps:
The above described steps can be in following sequence: 1,2,3,4,5, or 1,3,2,4,5, or 2,1,3,4,5, or 2,3,1,4,5 or 3,1,2,4,5 or 3,2,1,4,5.
Additional step of wiping off the condensation prior applying the label may be required in any of the sequences described.
As a preferred embodiment, the label comprises a thermoplastic facestock film. In another embodiment, the label comprises a vinyl or polyvinyl facestock including but not limited to polyvinyl chloride. In another embodiment, the label comprises a polyolefin facestock. In another embodiment, the label facestock comprises a woven material, cloth, nylon, paper, impregnated paper, thermoplastic, or any combination thereof.
The label facestock may comprise a topcoat for accepting the printing from laser (black-and-white or color) printer, ink-jet printer, thermal-transfer printer, direct-thermal printer, or from any combination thereof, or handwriting by using permanent ink marker, felt-tip marker, ballpoint pen, jell-based ink pen, pencil or combination thereof. In another embodiment, the facestock may not comprise a topcoat but still be capable accepting printing or handwriting from said printing or handwriting instruments.
The label comprises non-ionomer pressure-sensitive adhesive. As a preferred embodiment, the label comprises rubber adhesive. In another embodiment, the label comprises acrylic adhesive. In another embodiment, the label comprises hot-melt adhesive. In another embodiment, the label comprises any combination of non-ionomer pressure-sensitive adhesives.
As a preferred embodiment, the adhesive-coated labels are provided on a sheet comprising a liner. In another embodiment, the labels are provided on a roll or fanfold or a stripe comprising a liner.
As a preferred embodiment, the material is a adhesive-coated self-wound tape without a liner.
A crude label dispensing device (10) (see
The applicant conducted the following tests:
3 sets of 5 vials (1.5 ml polypropylene microtubes) were stored in dry ice (−78° C.) for 30 minutes. Preliminary 3 sets of 5 polyvinyl labels CL-3 (Cryogenic polyvinyl labels for laser printer sold by GA International Inc. since 2000) were cut to 1″×0.5″ size. First set of labels which were at room temperature were attempted to attach to the first set of frozen microtubes immediately after wiping off the condensation, but all the labels from first set detached immediately. The second set of labels was preheated up to 60-70° C. prior attaching to the microtubes. In the second set of microtubes, the condensation was wiped off as in the first set and all preheated labels adhered firmly to the vials and stayed attached after storing them back for at least 6 hours (time of observation) in dry ice. The third set of preheated labels were attempted to attach to microtubes without wiping off the condensation, but none of them adhered to the surface.
The same experiment was repeated with another cryogenic polyvinyl label for laser printer RCL-6 (Cryogenic polyvinyl labels for laser printer sold by GA International Inc. since 2002). The results were similar to CL-3 labels in set 1 and set 2. The set 3 of the RCL-6 preheated labels were able to adhere to microtubes even without wiping off the condensation, indicating that the adhesive in RCL-6 labels has a capability to adhere to wet surface.
This patent application claims priority on U.S. Provisional Patent Applications No. 60/867,215, filed on Nov. 27, 2006.
| Number | Date | Country | |
|---|---|---|---|
| 60867215 | Nov 2006 | US |
