Process for tinting plastic articles
View Patent ↗A process for tinting a molded article is disclosed. The process entails applying by spraying or by flow coating a hot, dye-solution onto at least a portion of the surface of a molded article to obtain a tinted article and washing the tinted article. In addition to the dissolved dye, the dye solution that is substantially free of particulate matter contains an aqueous solution of a carrier and an optional emulsifier. The article is one molded of a thermoplastic molding composition. In an embodiment of the invention, the dye solution is prepared by filtering a hot aqueous solution through a bag filter that contains a dye to obtain a hot, dye-solution. In a further embodiment, activated carbon is used to purify the dye solution to obtain a dye-free aqueous solution.
1. A process for tinting a molded article comprising applying by spraying or by flow coating a mixture to at least a portion of the surface of a molded article to obtain a tinted article and washing the tinted article, said mixture containing a dye and
(a) water in an amount of 60 to 70 pbw (percent by weight relative to the weight of the mixture)
(b) a carrier in an amount of 15 to 25 pbw and optionally
(c) an emulsifier in an amount of up to 15 pbw, said carrier conforming structurally to
R 1 [—O—(CH 2 ) n ] m OR 2
wherein R 2 and R 1 independently one of the other denotes H, C 1-18 alkyl, benzyl, benzoyl or phenyl radical which may be substituted in the aromatic ring by alkyl and/or halogen, n is 2 or 3 and m is 1 to 35, said article having been molded of a resinous molding composition, said mixture being at 50 to 98° C. and substantially free of particulate matter.
2. The process of claim 1 wherein the resinous molding composition is thermoplastic.
3. The process of claim 1 wherein the resinous molding composition is thermosetting.
4. The process of claim 2 wherein the thermoplastic contains at least one member selected from the group consisting of (co)polyester, (co)polycarbonate, (co)polyestercarbonate, styrenic (co)polystyrene, (co)polyacrylate, (co)polyamide, and (co)polyurethane.
5. The process of claim 4 wherein the thermoplastic contains at least one member selected from the group consisting polyester, polycarbonate, polyesterpolycarbonate copolymer, acrylonitrile-butadiene-styrene (ABS), polyamide, polyurethane, polymethylmethacrylate and styrene (co)polymer.
6. The process of claim 4 wherein the thermoplastic is polycarbonate.
7. The process of claim 1 wherein R 2 denotes butyl and R 1 denotes H.
8. The process of claim 1 wherein the mixture is prepared by filtering through a bag filter that contains a dye.
9. A process for tinting a molded article comprising applying by spraying or by flow coating a mixture to at least a portion of the surface of a molded article to obtain a tinted article, collecting the spent mixture and washing the tinted article, said mixture containing a dye and an aqueous solution of a carrier and an optional emulsifier, said article having been molded of a resinous molding composition, said mixture being at 50 to 98° C. and substantially free of particulate matter and passing the spent mixture through activated carbon under conditions calculated to separate the dye therefrom.
10. A process for tinting a molded article comprising applying by spraying a mixture to at least a portion of the surface of a molded article to obtain a tinted article and washing the tinted article, said mixture containing a dye and
(a) water in an amount of 60 to 70 pbw (percent by weight relative to the weight of the mixture)
(b) a carrier in an amount of 15 to 25 pbw and optionally
(c) an emulsifier in an amount of up to 15 pbw, said carrier conforming structurally to
R 1 [—O—(CH 2 ) n ] m OR 2
wherein R 2 and R 1 independently one of the other denotes H, C 1-18 alkyl, benzyl, benzoyl or phenyl radical which may be substituted in the aromatic ring by alkyl and/or halogen, n is 2 or 3 and m is 1 to 35, said article having been molded of a resinous molding composition, said mixture being at 50 to 98° C. and substantially free of particulate matter.
11. A process for tinting a molded article comprising applying by flow coating a mixture to at least a portion of the surface of a molded article to obtain a tinted article and washing the tinted article, said mixture containing a dye and
(a) water in an amount of 60 to 70 pbw (percent by weight relative to the weight of the mixture)
(b) a carrier in an amount of 15 to 25 pbw and optionally
(c) an emulsifier in an amount of up to 15 pbw, said carrier conforming structurally to
R 1 [—O—(CH 2 ) n ] m OR 2
wherein R 2 and R 1 independently one of the other denotes H, C 1-18 alkyl, benzyl, benzoyl or phenyl radical which may be substituted in the aromatic ring by alkyl and/or halogen, n is 2 or 3 and m is 1 to 35, said article having been molded of a resinous molding composition, said mixture being at 50 to 98° C. and substantially free of particulate matter.