Interference 103,685
dye and flame retardant treat (when flame retardant is
present) the fibers.
In another embodiment of the invention, we have
discovered the advantages of a two step process in which
a dye diffusion promoting agent is applied in an initial
step prior to further processing such as dyeing or treating
with a flame retardant or both. Initial treatment with a
dye diffusion promoting agent leaves residual promoting
agent on the aramid fabric, which may then be sold to
processors in this condition for subsequent dyeing and/or
flame retardant treating. The separate application of the
dye diffusion promoting agent prior to dyeing sometimes
results in better dyeing than does the use of the dye
diffusion promoting agent directly with the dye(s) as
well as higher levels of flame resistance.
The two-step process allows for the dyeing of fully
or partially constructed garments by first treating the
fabric width [sic] the dye diffusion promoting agent,
an effective amount of which remains on the fabric.
A garment is then fully or partially constructed and
dyed to the appropriate shade.
The specification of Riggins’ patent ultimately teaches (HX 1,
col. 7, l. 54, to col. 8, l. 67; emphasis added):
6. Dyeing - Among the monosubstituted amides . . .
only the butylbenzamide showed some promise as a dye
diffusion agent. Among the disubstituted amides . . .
and the pyrrolidones . . . the following dye diffusion
promotion agents all produced dark dyeing and are of
special interest:
No. of Swelling
No. Chemical Carbons Value
5 Dibutylformamide 9 1.5
7 Dibutylacetamide 10 4.5
8 Dipropylpropionamide 9 3.9
12 Dimethylhexamide 8 .9
15 Dimethylcaprylamide 10 2.2
18 Diethylbenzamide 11 3.6
19 Dipropylbenzamide 13 7.2
22 Cyclohexylpyrrolidone 10 5.5
23 n-Octylpyrrolidone 12 .1
-29-
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