Printable release

Information

  • Patent Grant
  • 5621030
  • Patent Number
    5,621,030
  • Date Filed
    Wednesday, June 7, 1995
    29 years ago
  • Date Issued
    Tuesday, April 15, 1997
    27 years ago
Abstract
The present invention is directed to a printable release composition used for pressure sensitive labels and the like. The invention is also directed to an article, such as a label, that comprises a substrate such as paper, optionally a thermal transfer primer coating coated onto the substrate and a release layer coated onto the transfer primer coating or onto the substrate. The printable release composition of the present invention may be used with labels having permanent, repositionable or removable adhesives. The particular composition of the release layer depends on the type of adhesive that is appropriate for the desired end use.
Description

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to printable release compositions for pressure sensitive adhesive articles, such as labels, and to articles containing such release compositions.
2. Description of the Prior Art
Many types of adhesive articles are known, such as labels, tapes, and note pads. Labels, in particular, are used for business forms, files, advertising, and the like. Labels come in a variety of shapes and sizes, such as window labels, machine labels, integrated labels and the like. Integrated labels are physically integrated, during manufacture, with business forms, mailings and the like.
The type of adhesive best suited for use with a particular article depends on the article's ultimate use. The adhesive may be repositionable, permanent or removable. For instance, it may be desirable for some applications to permanently affix an article to an object, for example, a label applied to a file folder. Such applications require a permanent adhesive. A repositionable adhesive, on the other hand, can be applied to an object, removed, and reapplied. Pads of notes, for example, NoteStix or PostIt notes, are examples of articles using repositionable adhesives. CleanTac is an example of a label having a repositionable adhesive. Finally, removable adhesives are appropriate when the article is to be removed after use, but is generally not reusable. Removable adhesives may, however, also include adhesives which become permanent over time.
Regardless of their use, adhesive articles must be stored and readily available for use. Such articles may utilize a separate disposable liner in juxtaposed face-to-face contact with the adhesive substrate with a release material coated on the side of the liner in contact with the adhesive side of the adhesive substrate. Just prior to use, the liner is peeled away from the adhesive. Such an adhesive article is often referred to as a "linered" label. Alternatively, the adhesive article may be a substrate coated on one side with a release material and coated on the opposite side with an adhesive material. Such a linerless label can be stored in pads or rolls.
The release coating facilitates either the removal of the adhesive-coated substrate from the liner or the pad or the unwinding the linerless label from the roll. The release coating needs to have sufficient adhesion to keep, for example, the linered label on its backing, or the linerless label on a pad or in a roll, but must have sufficient release properties to allow the label to be removed from the backing or pad or to be unwound from the roll, while maintaining its adhesive property.
For some time there have been problems in producing a release coating that possesses the above properties and that, additionally, contains printed matter. One problem relates to retaining the tenacity of the printed matter on the substrate so that the printed matter is not pulled off by the adhesive or wiped off by contact occasioned by someone rubbing against or applying the label. Another problem is "fill-in" of letters such as "o", "a", "e", etc. Fill-in occurs when the porosity of the substrate is not sufficient to absorb the ink and the ink has a tendency to feather out. Wipe-off and related problems may occur if the porosity of the substrate is too low and the ink does not dry sufficiently.
As an example of the above-mentioned problems, a release coating may be used for the printing of Postnet barcodes and FIM codes for automated mail processing. Postnet (Numerical Encoding Technique) is used to encode the ZIP code or ZIP+4 code on an envelope and is located in the lower right portion of a mail piece. FIMs (Facing Identification Marks) are used to identify Business Reply Mail and are a series of vertical bars printed in the upper middle portion of the mail piece just to the left of the postage indicia. FIMs greatly facilitate the automated processing of the mail; thus the quality and placement of the barcodes is very critical to the success of automated processing techniques. For instance, in a linerless label application, the barcode or barcodes are printed on the release surface of a substrate. If feathering or wipe off of the printed indicia occurs, then the information contained in the respective barcodes cannot be scanned. This may result in the loss of the cheaper bulk mailing rate. Standard postage for each piece must then be paid, increasing the cost to the customer, and the mail must be mechanically sorted, causing delay.
In the case of thermal transfer printing, not only is a high surface energy preferred, but the surface must be very smooth. Most thermal substrates contain clay coatings with relatively high surface energy and bending properties to enhance ink transfer and anchorage. A release coating imparts a lower surface energy to the face of the label for better release characteristics, making printing much more difficult. Thus, higher surface energy provides higher print quality, whereas lower surface energy provides for better release characteristics. Thus, there is a need for a printable release coating having both a good quality print and good release characteristics.
SUMMARY OF THE INVENTION
The present invention relates to printable release compositions for use with pressure sensitive adhesive articles, particularly labels. The release compositions provide appropriate release properties for the different adhesives: repositionable, permanent and removable.
The present invention is directed to a composition for uses as a release layer for a permanent adhesive comprising a mixture of:
(a) about 50 to about 95 parts by weight polyethylene; and
(b) about 5 to about 20 parts by weight silicon emulsion.
The present invention is also directed to a composition for use as a release layer for a repositionable adhesive comprising a mixture of:
(a) a major amount of ethylene vinyl chloride copolymer; and
(b) a minor amount of polyethylene emulsion.
In another embodiment, the present invention is directed to a composition for use as a release layer for a repositionable adhesive comprising:
(a) about 10 to about 80 parts by weight of a surfactant; and
(b) about 20 to about 90 parts by weight of an acrylic polymer.
In a further embodiment, the present invention is directed to an article comprising a substrate, a thermal transfer primer coating on the substrate, and a release layer on the thermal transfer primer coating wherein the thermal transfer primer coating comprises:
(a) about 20 to about 50 parts by weight of a latex; and
(b) about 50 to about 80 parts by weight pigment.
Additional advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The advantages of the invention may be realized and obtained by means of the elements and combinations particularly pointed out in the claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present invention as claimed.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is directed to an ink jet, video jet, and the like, printable release composition for use with pressure sensitive adhesives, such as labels and the like. The invention is also directed to an article, such as a label, that comprises a substrate such as paper, optionally a thermal transfer primer coating coated onto the substrate, and a release layer coated onto the thermal transfer primer coating or onto the substrate. The label may be either linerless or linered. The printable release composition of the present invention may be used with labels having permanent, repositionable or removable adhesives. The particular composition of the release layer depends on the type of adhesive that is appropriate for the desired end use.
In accordance with the present invention, as embodied and broadly described herein, a composition is provided for use as a release for a permanent adhesive. This composition comprises a mixture of:
(a) about 50 to about 95 parts by weight polyethylene; and
(b) about 5 to about 20 parts by weight silicon emulsion.
Preferably, the polyethylene has a melting point of 100.degree. C. or higher. The polyethylene is preferably an emulsion and may be obtained from commercial sources such as MICHEM 460, from Michelman, Inc., which is a polyethylene emulsion, having a density of 8.3, a pH of 10.1, a melting point of 110.degree. C., and a hardness of 1.5. Other emulsions that can be used include Michem 32535, 74040, 46025 and 6872 5, also from Michelman, Inc. Preferably, the composition contains about 80 to about 95 parts by weight polyethylene.
The silicon emulsion preferably contains an organopolysiloxane, such as methylhydrogen polysiloxane, for example, SYLOFF 1171 available from Dow Corning Corporation, or dimethyl polysiloxane, for example, "PC-107" available from Rhone-Poulenc. Preferably, the composition contains about 5 parts by weight silicon emulsion.
The composition may further comprise up to about 20 parts by weight ethylene vinyl chloride copolymer. The ethylene vinyl chloride copolymer blend may be, for example, VALCOAT 531 available from Air Products & Chemicals, Inc.
The composition may also contain other additives which do not adversely affect the desired properties of the release, such as pigments, thickeners, binders and amphipathic materials.
Examples of pigments that can be included in the thermal transfer primer coating composition include, for example, BURGESS No. 28, available from Burgess Pigment, and SUPERMITE, available from ECC International. A vinyl acetate ethylene binder also may be used in the thermal transfer barrier coating composition of the invention, such as AIRFLEX 1650, from Air Products. Examples of suitable binders that can be included in the thermal transfer barrier coating composition include, for example, AIRFLEX 100 HS from Air Products Corp., CARGILL 6431 from Cargill, KRISTALEX 3070 from Hercules, REICHHOLD 68-010 from Reichhold Chemical, and UCAR LATEX 376 from Union Carbide. Amphipathic materials that can be included in the release composition include ALIPAL CD-128 from GAF Corp., PLURONIC L-101 from BASF Corp., surfactant M-310 from Texaco, TEXAPHOR 963 from Henkel Corp., and TRITON GR5M from Union Carbide and amphipathic surfactant AEROSOL 22, C.sub.26 H.sub.43 NO.sub.10 Na.sub.4 S, from American Cyanamid Co. The amphipathic materials increase the release and printing properties.
In accordance with the invention, as embodied and broadly described herein, a composition is provided for use as a release for a repositionable adhesive which comprises a mixture of:
(a) a major amount of ethylene vinyl chloride copolymer; and
(b) a minor amount of a polyethylene emulsion.
Polyethylene emulsions that can be used in the invention include, but are not limited to, MICHEM 460, MICHEM 32535 MICHEM 68725, MICHEM 74040 and MICHEM 46025. Preferably, the composition contains about 60 to about 90 parts by weight ethylene vinyl chloride copolymer, and most preferably about 75 parts by weight ethylene vinyl chloride copolymer.
Ethylene vinyl chloride copolymers blends that can be used in the invention include, but are not limited to, VALCOAT 531. Preferably, the composition contains about 10 to about 40 parts by weight polyethylene emulsion, and most preferably about 25 parts by weight polyethylene emulsion.
The composition can also contain other additives which do not adversely affect the desired properties of the release, such as the pigments, thickeners, binders and amphipathic materials described above.
In accordance with the invention, as embodied and broadly described herein, a release composition is provided which comprises:
(a) about 10 to about 80 parts by wet weight of a surfactant; and
(b) about 20 to about 90 parts by wet weight of an acrylic copolymer.
The surfactant may be selected from, for example, sulfosuccinamate compounds, preferably tetrasodium N-(1,2-dicarboxyethyl)-N-octadecyl sulfosuccinamate. Other surfactants include SURFACT M-310 (Texaco), ALIPAL CD-128 (GAF Corp) and TRITON GR5M (Union Carbide). A particular sulfosuccinamate that may be used in the invention is AEROSOL 22, available from American Cyanamid Co. The release composition preferably contains about 20 to about 60 parts by weight of a surfactant. The composition may also contain calcium stearate, in a MICHEM 170 emulsion.
The acrylic copolymer may be selected from, for example, commercial formulations such as ACRYSOL ASE-60 from Rohm and Haas Co. Another source is ALCOGUM L-31, from Alco Chemicals. The release composition preferably contains about 40 to about 80 parts by weight of an acrylic copolymer.
The release composition described above comprising a surfactant and an acrylic polymer is particularly suited for use as an ink-jet printable release. The release composition works well with the ink-jet to accept ink due to proper porosity and release. The ink is partially absorbed into the substrate so that it dries quickly and does not feather. Water based ink-jet, such as VideoJet, produces better print quality and drying times with formulas consisting of at least 50 parts of acrylic polymer. Better print quality and drying time for oil based ink-jet, such as Trident, require at least 60 parts of the acrylic polymer.
The release suited for use as an ink-jet printable release may also contain about 10 to about 20 parts by weight calcium stearate emulsion such as MICHEM 170 by Michelman, Inc. for enhanced edge definition.
The ink-jet printable release may be coated on substrates, preferably 20# or 24# standard paper, such as 24# Union Camp Alkaline. The ink-jet release compositions are preferably coated at 0.37-1.8 gsm using a meyer rod, dahlgren, reverse roll, direct gravure, reverse gravure, direct and offset flexo. The release layer is printable with flexo, litho, gravure and dot matrix and laser.
Any of the release compositions described above may be coated on a substrate such as paper to obtain an article, preferably a label. The article may be prepared by coating the release composition onto at least a portion of one side of the substrate. A layer of a thermal transfer primer coating may be juxtaposed between the substrate and the release layer.
The article may contain a permanent or repositionable adhesive depending on its intended use. The release layer composition should be selected accordingly. The adhesive is applied either on the side of the substrate opposite the release layer, e.g., a linerless label, or on at least a portion of one side of a different substrate, wherein the adhesive layer is in juxtaposed contact with the release layer, e.g., a linered label.
Improved image quality may be obtained on plain paper (e.g., Finch Fine 24# stock) if the paper has been pre-coated with a thermal transfer primer coating. A thermal transfer primer coating provides for a smoother contact surface between the paper and the printhead. It also acts as an insulating layer or barrier by keeping the heat generated during the printing operation from penetrating into the paper. Printing ribbons have a wax coating which melts to release the ink. By keeping the heat on the surface, the ink is forced to print on the release surface, improving the print quality and producing a superior image. The thermal transfer primer coating also functions to bind the release coating to the substrate, enhancing the scratch and scuff resistance of the release.
Instead of a thermal transfer primer coating, a barrier coating may be provided between the substrate and the release, which may be, for example, vinyl acetate/ethylene copolymers such as AIRFLEX 1650 by Air Products.
In accordance with the invention, as embodied and broadly described herein, an article is provided comprising a substrate, a thermal transfer primer coating coated on the substrate, and a release layer coated on the thermal transfer primer coating. The thermal transfer primer coating comprises:
(a) about 20 to about 50 parts by weight of a latex; and
(b) about 50 to about 80 parts by weight pigment.
The pigment may be selected from, for example, ROPAQUE 84, by Rohm and Haas Co. The pigment preferably has a small particle size to obtain a smooth coating. Preferably, the thermal transfer primer coating includes about 80 parts by weight of pigment.
The latex may be, for example, commercial formulations such as LATEX 620 by Dow Chemical. Preferably, the thermal transfer primer coating includes about 20 parts by weight of a latex.
The substrate usable in the invention are preferably #24 or #20 paper. Commercial paper may be used such as 20# Finch Fine, Consolidated, and other types of thermal transfer sheets commercially available. Other substrates include films, TYVEK, polyester, and the like. The coating weight of the thermal transfer primer coating is preferably 2.5 to 4.0 gsm, and more preferably 2.8 gsm to 3.8 gsm. The coating weight of the release composition is preferably 5.0 gsm to 8.0 gsm, and more preferably 5.6 gsm to 7.5 gsm.
The substrate is precoated with the thermal transfer primer coating, if desired, then a release composition is prepared and coated on the thermal transfer primer coating, or on the substrate if no thermal transfer primer coating is present, using a coater, such as a Meyer Rod coater. Alternate methods are dahlgren, flexo, gravure blade or roll to roll. Preferably, a No. 28 Meyer Rod is used. A Meyer Rod is a coating rod or bar having different size diameters that can be selected for applying different amounts of coating.
The release composition described above comprising a surfactant and an acrylic polymer is particularly suited for use as an ink-jet printable release.
Water based ink-jet, such as VideoJet, produces better print quality and dry times with formulas consisting of at least 50 parts of acrylic polymer. Better print quality and dry time for oil based ink-jet, such as Trident, require at least 60 parts of the acrylic polymer.
The ink-jet printable release may also contain 10 to 20 parts calcium stearate emulsion such as MICHEM 170 by Michelman, Inc. for enhanced edge definition.
The ink-jet printable release is coated on substrates, preferably 20# or 24# standard paper, such as 24# Union Camp Alkaline.
The ink-jet release compositions are preferably coated at 0.37-1.8 gsm using a meyer rod, dahlgren, reverse roll, direct gravure, reverse gravure, direct and offset flexo. The release layer is printable with flexo, litho, gravure and dot matrix.
The following examples are illustrative, and are not intended to limit the scope of the present invention.
Examples 1 and 2 are directed to release compositions for use with repositionable adhesives.





EXAMPLE 1
A substrate was prepared by precoating with a thermal transfer primer coating.
Substrate
24# Finch Fine Paper
Thermal transfer primer coating
80 parts ROPAQUE 84
20 parts LATEX 620
Coat weight of 2.82 gsm
A release composition was prepared and coated on the thermal transfer primer coating of the substrate using a Meyer Rod coater with a No. 28 meyer rod.
Release
50 parts AEROSOL 22 Surfactant
50 parts ACRYSOL ASE 60
Coat weight of 5.64 gsm
Two week accelerated aging (AA) delamination values were in the 1.0-2.0 oz/in range. AA was performed under heated conditions of 120.degree. F.
EXAMPLE 2
Substrate
24# Consolidated Thermal Transfer Paper
A release composition was prepared and coated on the substrate.
Release
30 parts AEROSOL 22
70 parts ACRYSOL ASE-60
Coat weight 6.76 gsm
Two week AA delamination values were in the 1.0-2.0 oz/in range.
In examples 3-5, trials were conducted using the Meyer Rod coater to produce a permanent printable release for use with a permanent adhesive.
EXAMPLE 3
A substrate was prepared by precoating with a thermal transfer primer coating.
Substrate
24# Finch Fine paper
Thermal transfer primer coating
80 parts ROPAQUE 84
20 parts LATEX 620
coat weight 3.76 gsm
A release composition was prepared and coated on the thermal transfer primer coating.
Release
75 parts--Polyethylene, MICHEM 460
15 parts--Ethylene Vinyl Chloride, VALCOAT 531
10 parts--Silicone Emulsion, PCL 107
coat weight 7.5 gsm
EXAMPLE 4
A substrate was prepared by precoating with a thermal transfer primer coating.
Substrate
24# Finch Fine paper
Thermal transfer primer coating
80 parts ROPAQUE 84
20 parts LATEX 620
coat weight 2.82-3.76 gsm
A release composition was prepared and coated on the thermal transfer primer coating.
Release
80 parts Polyethylene, (MICHEM 460)
10 parts VALCOAT 531
10 parts PCL 107
coat weight 5.65-7.5 gsm
EXAMPLE 5
A substrate was prepared by precoating with a barrier coating.
Substrate
24# Finch Fine paper
Barrier
Vinyl Acetate/Ethylene Copolymer, AIRFLEX 1650
coat weight 2.8-6.5 gsm
A release composition was prepared and coated on the barrier coating.
Release
90 parts Polyethylene MICHEM 460
10 parts SYLOFF 1171
coat weight 5.6-7.5 gsm
None of the materials alone meets all the requirements for a good printable release. However, proper blends offer acceptable print and release.
In examples 6-8, trials were conducted using dahlgren to produce an ink-jet printable release. After a 2 week accelerated aging test at 120.degree. F., delamination values of less than 2.7 oz/in were obtained.
EXAMPLE 6
A substrate was coated with a release composition.
Substrate
24# Union Camp Alkaline
Release
50 parts AEROSOL 22
50 parts ASE-60
coat weight 1.5 gsm
EXAMPLE 7
A substrate was coated with a release composition.
Substrate
24# Union Camp Alkaline
Release
20 parts AEROSOL 22
80 parts ASE-60
coat weight 1.3 gsm
EXAMPLE 8
A substrate was coated with a release composition.
Substrate
24# Union Camp Alkaline
Release
18 parts AEROSOL 22
72 parts ASE-60
10 parts MICHEM 170
coat weight 1.3 gsm
Examples 6-8 exhibited good drying time, good dot uniformity and contrast and a good print contrast ratio greater than 75.
It will be apparent to those skilled in the art that various modifications and variations can be made in the compositions and methods of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
Claims
  • 1. A release composition comprising:
  • (a) about 10 to about 80 parts by wet weight of a sulfosuccinamate surfactant; and
  • (b) about 20 to about 90 parts by wet weight of an acrylic copolymer;
  • suitable for use as a release for a repositionable adhesive.
  • 2. The composition of claim 1, wherein the release layer comprises:
  • (a) about 20 to about 60 parts by wet weight sulfosuccinamate surfactant; and
  • (b) about 40 to about 80 parts by wet weight acrylic copolymer.
  • 3. The composition of claim 1, wherein the surfactant is tetrasodium N-(1,2-dicarboxyethyl)-N-octadecyl sulfosuccinamate.
  • 4. The release composition of claim 1, suitable for use as an ink-jet printable release.
Parent Case Info

This is a division of application Ser. No. 08/189,632, filed Feb. 1, 1994 now U.S. Pat. No. 5,478,880.

US Referenced Citations (72)
Number Name Date Kind
2647843 Bemmels Aug 1953
2888419 Safford May 1959
2897960 Revoir Aug 1959
2912348 Lavanchy Nov 1959
2992201 Gober Jul 1961
3390208 Montgomery Jun 1968
3442837 Brotz et al. May 1969
3458468 Tapp Jul 1969
3475196 Bartell et al. Oct 1969
3531316 Sternasty Sep 1970
3543920 Crocker et al. Dec 1970
3549482 Okutani Dec 1970
3607341 Goins et al. Sep 1971
3652314 Castner Mar 1972
3691257 Kendrick et al. Sep 1972
3788941 Kupits Jan 1974
3860540 Abel et al. Jan 1975
3862073 Bille et al. Jan 1975
3870546 Gelsomino Mar 1975
3873352 Kitaj Mar 1975
3882060 Guzy May 1975
4048380 Blakey et al. Sep 1977
4057662 Johnson et al. Nov 1977
4070523 Blum et al. Jan 1978
4084026 Gandia Apr 1978
4133774 Brynko et al. Jan 1979
4172910 Rotar et al. Oct 1979
4287108 Grigo et al. Sep 1981
4331736 Schafer et al. May 1982
4334878 Cutler et al. Jun 1982
4417016 Cline et al. Nov 1983
4440830 Wempe Apr 1984
4504619 Chang et al. Mar 1985
4536422 Harper, Jr. Aug 1985
4576610 Donenfeld Mar 1986
4579223 Otsuka et al. Apr 1986
4585497 Webster Apr 1986
4618512 Harper, Jr. Oct 1986
4664416 Steidinger May 1987
4728571 Clemens et al. Mar 1988
4788084 Morin Nov 1988
4803194 Bracewell Feb 1989
4880678 Goffi Nov 1989
4921882 Senich May 1990
4927709 Parker et al. May 1990
4931492 Foster et al. Jun 1990
4935300 Parker et al. Jun 1990
5064908 Schuster et al. Nov 1991
5073457 Blackwell Dec 1991
5115029 Kirkpatrick et al. May 1992
5154962 Mertens et al. Oct 1992
5169900 Gudelis Dec 1992
5210121 Hinterwaldner May 1993
5217793 Yamane et al. Jun 1993
5221706 Lee et al. Jun 1993
5238644 Boulanger et al. Aug 1993
5238731 Blanch et al. Aug 1993
5239018 Yezrielev et al. Aug 1993
5246756 All et al. Sep 1993
5248535 Chang et al. Sep 1993
5250336 Greuse et al. Oct 1993
5310772 Blanch et al. May 1994
5320780 Unruh Jun 1994
5443759 Dahms Aug 1995
5447784 Williams et al. Sep 1995
5453270 Bills Sep 1995
5453459 Roberts Sep 1995
5458678 Armstrong et al. Oct 1995
5464633 Conte et al. Nov 1995
5474712 Dotolo et al. Dec 1995
5474818 Ulrich et al. Dec 1995
5475154 Lundquist et al. Dec 1995
Foreign Referenced Citations (6)
Number Date Country
58-203176 May 1982 JPX
337457 May 1972 SUX
1293797 Oct 1972 GBX
WO8807931 Oct 1988 WOX
WO9204409 Mar 1992 WOX
WO9314932 Aug 1993 WOX
Non-Patent Literature Citations (3)
Entry
Derwent Abstract No. 86-202436.
Derwent Abstract No. 92-212096.
Notification of Transmittal and International Search Report including Annex, PCT US 95 00539 dated May 24, 1995.
Divisions (1)
Number Date Country
Parent 189632 Feb 1994