Binderless thermotropic jet ink

• US 4,166,044 A
• Filed: 05/30/1978
• Issued: 08/28/1979
• Est. Priority Date: 05/30/1978
• Status: Expired due to Term

• Current Assignee: United States Gypsum Company (GEBR Knauf Verwaltungsgesellschaft KG)
• Original Assignee: United States Gypsum Company (GEBR Knauf Verwaltungsgesellschaft KG)
• Inventors: Zimmerman, Paul, Germonprez, Raymond L.
• Primary Examiner(s): Sebastian, Leland A.
• Application Number:
  US05/910,900
• Time in Patent Office: 455 Days
• Field of Search: 73/356, 101/32, 252/408 R, 23/230 R, 428/913, 206/459, 106/8, 106/22
• US Class Current: 252/408.1
• CPC Class Codes: C09D 11/36 based on non-aqueous solvents
• CPC Class Codes: C09D 11/50 Sympathetic, colour changing or similar inks
• CPC Class Codes: Y10S 252/962 Temperature or thermal history
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture

Abstract

Binderless ink compositions suitable for use in jet printing operations on polymeric resin surfaces to form images which are highly resistant to abrasion and to steam pasteurization or sterilization conditions by penetration of the colorant into the sub-surface structure of the resin, are provided. The ink compositions are thermotropic, i.e. they change color in the presence of water or steam at elevated temperature and are useful as sterilization or pasteurization indicators. The preferred inks comprise either (1) a colorant which reacts under the sterilization conditions or (2) a combination of colorants one of which is extractible under sterilization conditions; a water and alcohol solvent system; a surfactant; an aliphatic or cyclic ketone, aldehyde, acetal, ether or ester and, optionally, an aliphatic hydrocarbon of 8-12 carbons.

Claims

1. A binderless ink composition, suitable for use in ink jet printing operations and capable of bonding to synthetic polymeric resin surfaces by softening and swelling the surface layers of the polymeric resin to allow penetration of the ink, which comprises a solution of:

(1) a colorant selected from the group consisting of (a) a reactive thermotropic dye capable of exhibiting a visible color change upon exposure to steam at a temperature of at least about 215°

F. and (b) a combination of dyes of different color capable of exhibiting a visible color change upon exposure to water or steam at a temperature of at least about 120°

F.;

(2) a solvent consisting essentially of from about 10 to about 35 percent of water, from about 6 to about 25 percent of an aliphatic alcohol having 1 to 3 carbon atoms or mixtures thereof and from about 25 to about 75 percent of an organic compound selected from the group consisting of aliphatic and cyclic ketones, amides, acetals, ethers and esters;

(3) from about 8 to about 17 percent of a surfactant and

(4) from about 0 to about 10 percent of an aliphatic hydrocarbon having from 8 to 12 carbon atoms, the total percentage of the components amounting to 100%.

2. An ink composition as claimed in claim 1, wherein said colorant is a reactive thermotropic dye.

3. An ink composition as claimed in claim 1, wherein said colorant is a combination of dyes of different color.

4. An ink composition as claimed in claim 2 or 3, wherein said organic compound is 2-heptanone, said aliphatic alcohol is methanol or mixture thereof with ethanol, said surfactant is sodium lauryl sulfate and said aliphatic hydrocarbon is 1-decene.

5. An ink composition as claimed in claim 4, wherein said thermotropic dye is a phenazine dye.

6. An ink composition as claimed in claim 4, wherein said combination of dyes is an extractible/nonextractible dye pair.

7. A binderless ink composition, suitable for use in ink jet printing operations and capable of bonding to synthetic polymeric resin surfaces by softening and swelling the surface layers of the polymeric resin to allow penetration of the ink which comprises a solution of 1% of a reaction pehenazine dye capable of exhibiting a color change upon exposure to steam at a temperature of at least about 215°

F., 57% 2-heptanone, 12% methanol, 3% 1-decene, 13% sodium lauryl sulfate, and 14% water.

8. An ink composition as claimed in claim 7 wherein said dye is Janus Blue.

9. A binderless ink composition, suitable for use in ink jet printing operations and capable of bonding to synthetic polymeric resin surfaces by softening and swelling the surface layers of the polymeric resin to allow penetration of the ink which comprises a solution of 1% of a combination of dyes of different color of which one is extractible upon exposure to water or steam at a temperature of at least about 120°

F., 57% 2-heptanone, 12% methanol, 3% 1-decene, 13% sodium lauryl sulfate and 14% water.

10. An ink composition as claimed in claim 9 wherein said dye combination is 0.6% Victoria Blue and 0.4% Palacet Yellow.

11. A method of indicating sterilization of articles having synthetic polymeric resin surfaces which comprises applying markings to a surface of said article using a binderless ink composition comprising a solution of:

(1) a colorant selected from the group consisting of (a) a reactive thermotropic dye capable of exhibiting a visible color change upon exposure to steam at a temperature of at least about 215°

F. and (b) a combination of dyes of different color capable of exhibiting a visible color change upon exposure to water or steam at a temperature of at least about 120°

F.;

(2) a solvent consisting essentially of from about 10 to about 35 percent of water, from about 6 to about 25 percent of an aliphatic alcohol having 1 to 3 carbon atoms or mixtures thereof and from about 25 to about 75 percent of an organic compound selected from the group consisting of aliphatic and cyclic ketones, amides, acetals, ethers and esters;

(3) from about 8 to about 17 percent of a surfactant;

(4) from about 0 to about 10 percent of an aliphatic hydrocarbon having 8 to 12 carbon atoms;

the total components amounting to 100%, and exposing the marked articles to water or steam at sufficient temperature for a sufficient time to effect a visible color change in said markings.

12. A method as claimed in claim 11, wherein said articles are polymeric resin coated metal containers.

13. A method as claimed in claims 11 or 12 wherein said organic compound is 1-heptanone, said aliphatic alcohol is methanol, or mixture thereof with ethanol, said surfactant is sodium lauryl sulfate and said aliphatic hydrocarbon is 1-decene.

14. A method as claimed in claims 11, 12 or 13 wherein said markings are applied by jet ink printing of said ink composition.

19. A method as claimed in claims 11, 15, or 17 wherein said articles are polymeric resin coated metal containers.

15. A method of indicating steam sterilization of articles having polymeric resin surfaces which comprises:

applying ink jet printed markings to at least one surface of said article employing a binderless ink composition which swells and softens the polymeric resin to allow penetration of the ink, said ink composition comprising a solution of (1) a reactive phenazine dye, (2) a solvent consisting essentially of from about 10 to about 25 percent of water, from about 6 to about 25 percent of an aliphatic alcohol having 1 to 3 carbon atoms or mixtures thereof and from about 25 to about 75 percent of an organic compound selected from the group consisting of 2-butanone, 2-pentanone, 2-hexanone, 2-octanone, 2,4-pentandione, furan, dioxane, ethyl acetate, propyl acetate, butyl acetate, diemthyl acetamide, and mixtures thereof;

(3) from about 8 to about 17 percent of a surfactant and (4) from about 0 to about 10 percent of an aliphatic hydrocarbon having from 8 to 12 carbon atoms;

and exposing the marked articles to steam at a temperature of at least about 215°

F. for a period of time sufficient to effect a visible color change in said markings.

16. A method as defined in claim 15 wherein said ink composition comprises 1% Janus Blue, 57% 2-heptanone, 12% methanol, 3% 1-decene, 13% sodium lauryl sulfate and 14% water.

17. A method of indicating sterilization of articles having polymeric resin surfaces which comprises:

applying ink jet printed markings to at least one surface of said article employing a binderless ink composition which swells and softens the polymeric resin to allow penetration of the ink, said ink composition comprising a solution of (1) a pair of extractible/non-extractible dyes of different color;

(2) a solvent consisting essentially of from about 10 to about 25 percent of water, from about 6 to about 25 percent of an aliphatic alcohol having 1 to 3 carbon atoms or mixtures thereof and from about 25 to about 75 percent of an organic compound selected from the group consisting of 2-butanone, 2-pentanone, 2-hexanone, 2-octanone, 2,4-pentandione, furan, dioxane, ethyl acetate, propyl acetate, butyl acetate, dimethyl acetamide, and mixtures thereof;

(3) from about 8 to about 17 percent of a surfactant and (4) from about 0 to about 10 percent of an aliphatic hydrocarbon having from 8 to 12 carbon atoms;

and exposing the marked articles to water at a temperature of at least about 120°

F. for a period of time sufficient to extract said extractible dye from said printed markings and thereby effect a visible color change in said markings.

18. A method as defined in claim 17 wherein said ink comprises 0.6% Victoria Blue, 0.4% Palacet Yellow, 57% 2-heptanone, 12% methanol, 3% 1-decene, 13% sodium lauryl sulfate and 14% water.