Claims
- 1. A method for modifying a vesicular image present in a hydrophobic thermoplastic layer selected from the group consisting of polyvinylidene chloride, polymethacrylonitrile, polystyrene and polyepoxide polymers and co-polymers made from acrylonitrile with ethyl acrylate and co-polymers of acrylonitrile with vinylidene chloride into a non-light-scattering image which method comprises
- a. opening the closed bubbles of the vesicular image to form an open-pore image by allowing at least one organic lipophilic solvent which attacks the thermoplastic bubble walls of the vesicular image to act on the latter,
- b. introducing the image substance selected from the group consisting of dyestuffs, optical brighteners and ultraviolet absorbers into the open pores by treatment with a solution in a hydrophilic solvent or with a dispersion of the image substance,
- c. removing the excess adhereing image substance solution by briefly flushing with water, and
- d. removing any remaining gas bubbles or closing the pores by a heat treatment or a treatment with a highly volatile organic solvent and drying the image material.
- 2. Method according to claim 1 which comprises using a dyestuff as image substance.
- 3. Method according to claim 1 which comprises using an ultraviolet absorber or an optical brightener as image substance.
- 4. Method according to claim 1, which comprises using a lipophilic solvent to open the bubbles and a hydrophilic solvent to dissolve the image substance.
- 5. Method according to claim 1, which comprises wetting the open pore image with a surfactant and treating the image thereafter with an aqueous solution of the image substance.
- 6. Method according to claim 1, which comprises using a water-soluble dyestuff as image substance.
- 7. Method according to claim 1, which comprises opening the bubbles by immersion in vapour from acetone, methylene chloride or dimethyl formamide for 1 to 20 seconds.
Priority Claims (1)
Number |
Date |
Country |
Kind |
3822/70 |
Mar 1970 |
CH |
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Parent Case Info
This is a continuation-in-part of our patent application Ser. No. 370,896, filed June 18, 1973, now abandoned, which in turn is a divisional of our patent application Ser. No. 123,821, now abandoned, filed Mar. 12, 1971.
US Referenced Citations (12)
Foreign Referenced Citations (3)
Number |
Date |
Country |
2,084,439 |
Dec 1971 |
FR |
645,825 |
Sep 1945 |
UK |
1,091,501 |
Nov 1967 |
UK |
Divisions (1)
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Number |
Date |
Country |
Parent |
123821 |
Mar 1971 |
|
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
370896 |
Jun 1973 |
|