Formulations Having Benzoate Dye Carriers for Meta-Aramid Articles
Glycol ether benzoates, glycol benzoates and methyl benzoate facilitate the dyeing of the meta-aramid article, e.g., fibers, at or near neutral pH. The addition of an anionic surfactant, such as sodium lauryl sulfate, enhances the performance of the benzoates.
1 . An aqueous dye formulation comprising:
A. A cationic dye;
B. At least one of a glycol ether benzoate and glycol benzoate;
C. Water; and
D. Optionally, an anionic surfactant.
2 . The dye formulation of claim 1 having a pH of 6-8.
3 . The dye formulation of claim 1 in which the glycol ether benzoate is of the formula
R 1 —O—(CH 2 CH(R 2 O) n —R 3
in which R 1 is a C 1-10 alkyl group, phenyl or benzyl, R 2 is either hydrogen, methyl or ethyl, R 3 — is C═C—C 6 H 5 from benzoic acid, and n=1-3.
4 . The dye formulation of claim 3 in which the dye is present in an amount of 0.05 to 5 wt %, the at least one of a glycol ether benzoate and glycol benzoate is present in an amount of 3 to 6 wt %, and the water is de-ionized.
5 . The dye formulation of claim 4 in which the glycol ether benzoate is at least one of 1-methoxy-2-propylbenzoate, 2-propoxyethyl benzoate, 2-butoxyethyl benzoate, 2-(2-phenoxyethoxy)ethyl benzoate and 2-(2-phnoxy-1-methylethoxy)-1-methylethoxy benzoate; and the glycol benzoate is at least one of a diethylene glycol mono- and dibenzoates, dipropylene glycol mono- and dibenzoates, triethylene glycol benzoates and trimethylene glycol dibenzoate.
6 . The dye formulation of claim 5 in which the anionic surfactant is present in an amount of 1-4 wt %.
7 . The dye formulation of claim 6 in which the anionic surfactant is a linear alkyl sulfonate.
8 . A method of dyeing a meta-aramid article, the method comprising the step of contacting the meta-aramid article with a dye formulation comprising:
A. A cationic dye;
B. At least one of a glycol ether benzoate and glycol benzoate;
C. Water; and
D. Optionally, an anionic surfactant;
the dye formulation having a pH of 6-8.
9 . The method of claim 8 in which the article is immersed in a bath of the dye formulation.
10 . . A meta-aramid article dyed by the method of claim 8 .
11 . . The article of claim 10 in the form of a fiber.