Process for making dyed articles
View Patent ↗A process of dyeing a molded article is disclosed. The process entails immersing at least a portion of the article in a dyeing bath, retaining the portion in the bath for a period of time sufficient to allow an amount of dye to diffuse into the article, and removing said article from the bath. The molded article comprises a polymeric resin such as (co)polyester, (co)polycarbonates, acrylonitrile-butadiene-styrene, polyamide, polyurethane, polyalkyl(meth)-acrylate, allyldiglycol carbonate and styrene copolymers. The dyeing bath contains in addition to dye, water, a plasticizing agent and a leveling agent.
1. A dyed article prepared by a process comprising the steps of
(i) immersing at least a portion of an article in a dyeing bath maintained at a temperature of 60 to 99°C. and
(ii) retaining said portion in said bath for a period of time sufficient to allow an amount of dye to diffuse into said article, and
(iii) removing said article from said bath,
wherein molded article comprises at least one polymeric resin selected from the group consisting of (co)polyester, (co)polycarbonates, acrylonitrile-butadiene-styrene, polyamide, polyurethane, polyalkyl(meth)acrylate, allyldiglycol carbonate and styrene copolymers, and wherein the bath contains
(a) 50 to 90 pbw relative to the weight of the bath of water
(b) 0.1 to 15 pbw of dye
(c) 2.5 to 20 pbw of at least one plasticizing agent conforming to
R′—[(O(CH 2 ) m ) n —]OH
where R′ is an ethyl, propyl or butyl radical,
m is 2, 3 or 4, and
n is 1, 2 or 3
with the proviso that where R′ is butyl m is 2 or 4 and
(d) 5 to 30 pbw of at least one leveling agent conforming structurally to
H—[(O(CH 2 ) m ) n ]OH
where m is 2, 3 or 4 and
n is 1, 2, or 3.
2. The dyed article of claim 1 wherein the bath further contains a surfactant.
3. The dyed article of claim 1 wherein the dye is disperse dye.
4. The dyed article of claim 3 wherein the bath further contains a surfactant.
5. The dyed article of claim 1 wherein the dye is a water-insoluble dye selected from the group consisting of azo, diphenylamine and anthraquinone compounds.
6. The dyed article of claim 1 wherein the resin is aromatic polycarbonate.
7. The dyed article of claim 1 wherein the plasticizing agent is a member selected from the group consisting of ethylene glycol butyl ether, diethylene glycol ethylether, diethylene glycol butylether, propylene glycol propylether, dipropylene glycol propyl ether and tripropylene glycol propylether.
8. The dyed article of claim 1 wherein the leveling agent is a member selected from the group consisting of diethylene glycol, triethylene glycol and 1,4-butanediol.