U.S. patent number 3,653,803 [Application Number 04/884,311] was granted by the patent office on 1972-04-04 for polyolefin and ethylene-amino acrylate copolymer blend dilute acid scoured and dyed.
This patent grant is currently assigned to E. I. du Pont de Nemours and Company. Invention is credited to Clarence Frederick Hammer.
United States Patent |
3,653,803 |
Hammer |
April 4, 1972 |
POLYOLEFIN AND ETHYLENE-AMINO ACRYLATE COPOLYMER BLEND DILUTE ACID
SCOURED AND DYED
Abstract
A process for acid dyeing polyolefin (isotactic polypropylene)
shaped articles such as fibers is provided which gives full
penetration of dye to heavy denier round fibers in relatively short
periods of time as well as adequate penetration of very heavy tape
and fibrillated film fibers. This process comprises (1) extruding a
uniform blend of the polyolefin with about 2 to 15 percent by
weight of a thermoplastic, essentially compatible
nitrogen-containing polymer such as a copolymer of ethylene and
dimethylaminoethyl methacrylate into fibers, (2) exposing the
fibers to an aqueous prescour solution which contains about 3 to
200 percent, on weight of fiber, of various scour materials,
preferably sodium bisulfate, and optionally a non-ionic surfactant,
at a temperature of about 80.degree. to 1290.degree. C., and (3)
exposing the fibers to an acid dye bath, containing an acid dye, a
premetallized dye, a disperse dye or mixtures thereof.
Inventors: |
Hammer; Clarence Frederick
(Wilmington, DE) |
Assignee: |
E. I. du Pont de Nemours and
Company (Wilmington, DE)
|
Family
ID: |
25384360 |
Appl.
No.: |
04/884,311 |
Filed: |
December 11, 1969 |
Current U.S.
Class: |
8/540; 8/539;
8/904; 8/931; 8/531; 8/617; 8/929; 264/78 |
Current CPC
Class: |
C08L
23/10 (20130101); C08L 23/02 (20130101); C08L
23/10 (20130101); C08L 23/02 (20130101); D06P
3/791 (20130101); C08L 23/0892 (20130101); C08L
2666/04 (20130101); D06P 3/794 (20130101); Y10S
8/931 (20130101); Y10S 8/929 (20130101); Y10S
8/904 (20130101) |
Current International
Class: |
D06P
3/79 (20060101); C08L 23/00 (20060101); C08L
23/02 (20060101); D06p 003/00 () |
Field of
Search: |
;8/168,180,31,100,115.5
;200/879B |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Levy; Donald
Claims
What is claimed is:
1. A process for dyeing shaped articles based on a polyolefin
comprising: (1) forming into a shaped article a uniform blend of
about 98 to 85 percent by weight of a polyolefin and about 2 to 15
percent by weight of an ethylene copolymer comprising about 60 to
80 percent by weight ethylene and about 40 to 20 percent by weight
of an amino acrylate of the formula
wherein R is hydrogen or methyl:
R.sup.1 is hydrogen or alkyl of one to three carbon atoms;
R.sup.2 is alkyl of one to three carbon atoms, or t-butyl when
R.sup.1 is hydrogen; and
A is alkylene of two to three carbon atoms;
(2) exposing the shaped article to a dilute aqueous prescour
solution which is separate from the dye bath containing about 3 to
200 percent, on weight of shaped article, of a scour material
selected from the group consisting of hydrochloric acid, sulfuric
acid, sulfamic acid, sodium bisulfate, phosphoric acid, p-toluene
sulfonic acid, and sodium dihydrogen phosphate, at a temperature
within the range of about 80.degree. to 120.degree. C.; and (3)
exposing the prescoured shaped article to an acid dye bath
containing an acid dye, a premetallized dye, a disperse dye or
mixtures thereof, said bath having a pH within the range of 3 to
7.
2. The process of claim 1 wherein the polyolefin is isotactic
polypropylene and the shaped articles are fibers.
3. The process of claim 2 wherein the prescour solution
additionally contains about 0.25 to 2 percent, on weight of fiber,
of a non-ionic surfactant.
4. The process of claim 3 wherein the prescour solution contains
about 5 to 15 percent, on weight of fiber, of sodium bisulfate.
5. The process of claim 4 wherein a non-ionic spinning finish is
applied to the extruded fibers.
6. The process of claim 4 wherein the dye bath additionally
contains about 0.25 to 2 percent, on weight of fiber, of a
non-ionic surfactant.
7. The process of claim 6 wherein the dye bath additionally
contains a carrier.
8. The process of claim 7 wherein the carrier is a hydrocarbon,
chlorinated hydrocarbon or mixtures of either.
9. A process for dyeing fibers based on polypropylene comprising:
(1) uniformly blending isotactic polypropylene with about 4 to 10
percent by weight of an ethylene copolymer of about 60 to 80
percent by weight ethylene and about 40 to 20 percent by weight of
an amino acrylate of the formula:
wherein R is hydrogen or methyl;
R.sup.1 is hydrogen or alkyl of one to three carbon atoms;
R.sup.2 is alkyl of one to three carbon atoms, or t-butyl
when R.sup.1 is hydrogen; and
A is alkylene of two to three carbon atoms; (2) extruding the
uniform blend into fibers; (3) exposing the fibers to a dilute
aqueous prescour bath which is separate from the dye bath
containing about 5 to 15 percent, on weight of fiber, of sodium
bisulfate and about 0.25 to 2 percent, on weight of fiber, of a
non-ionic surfactant at a temperature of about 80.degree. to
120.degree. C.; and (4) exposing the prescoured fibers to an acid
dye bath containing an acid dye, said bath having a pH within the
range of about 3 to 7.
10. The process of claim 9 wherein the amino acrylate is
dimethylaminoethyl methacrylate.
11. The process of claim 10 wherein the dye bath additionally
contains about 0.25 to 2 percent, on weight of fiber, of a
non-ionic surfactant.
12. The process of claim 11 wherein the extruded fibers are round
fibers of about 1 to 60 denier and the initial pH of the dye bath
is within the range of about 3 to 5.
13. The process of claim 11 wherein the extruded fibers are tape
fibers of about 500 to 1,500 denier and are dyed together with
nylon fibers in a dye bath containing both an anionic and non-ionic
surfactant and in which the initial pH of the dye bath is within
the range of about 6 to 7 and is decreased to less than pH 4 when
the bath temperature reaches at least about 80.degree. C.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to processes for preparing acid-dyeable
polyolefin fibers and more particularly to processes for acid
dyeing a blend of polypropylene and a thermoplastic essentially
compatible nitrogen-containing polymer.
2. Description of the Prior Art
Polyolefins are difficult to dye in that they lack dye sites to
which dye molecules may become attached. In the prior art it is
known to add dye receptor materials such as various nitrogen-based
polymers to the polyolefins to make them dyeable. For instance, in
U.S. Pat. No. 3,361,843 issued to Robert Miller and Frederick C.
Loveless on Jan. 2, 1968, various incompatible, basic
nitrogen-based polymers are added to polymers, particularly
polypropylene, given a treatment with high concentrations of
certain acidic chemical reagents and then dyed in an acid dye bath.
Although dyeing of the polypropylene fiber is somewhat improved,
processing of the fiber is difficult due to the incompatible
polymer, and the dye fastness properties and tinctorial strength
are not as they should be to be commercially feasible.
It is well known that incompatible polymeric additives are
difficult to process into fibers continuously due to build-up of
the additive on the spinneret face plate and on the rolls of the
processing equipment after several hours of operation. The
incompatible material tends to cause blockage of screens and/or
sand packs placed ahead of the spinneret to filter the polymer
blend. Agglomeration of particles of the incompatible additive in
the fiber leads to yarn breaks during the spinning and drawing
operations. Also, the tinctorial strength of dyed fiber containing
incompatible additive is highly dependent on the shear history of
the polymer blend, i.e., samples having been exposed only to
relatively low shear in the blending and spinning operations will
contain large particles of the additive, while those samples
exposed to high shear will contain small particles. In subsequent
dyeings, fibers containing large particles will show dyed and
undyed portions, while fibers containing very small particles will
appear uniformly colored, but relatively weak in tinctorial
strength. Between these extremes is an optimum particle size which
gives best tinctorial strength. The molecular weight of the
incompatible additive also affects tinctorial strength of the dyed
fiber, lower molecular weight giving better tinctorial strength,
but less resistance to extraction during dyeing operations.
Molecular weight can be affected by the thermal history of the
blend, excessive heat causing degradation of the additive.
Since shear history and thermal history both affect tinctorial
strength of the incompatible polymeric additives disclosed in U.S.
Pat. No. 3,361,843, and U.S. Pat. No. 3,433,853 issued to Ralph H.
Earle, Alfred C. Schmalz and Charles A. Soucek on Mar. 18, 1969, it
is difficult to obtain reproducibly dyed fibers from polypropylene
modified by such additives.
In U.S. Pat. No. 3,395,198 issued to Isaji Taniguchi et al. on July
30, 1968, various compatible nitrogen-containing polymers are
disclosed which, when blended with polyolefins, render fibers
formed from the blend acid dyeable. However, dyeings of such
modified polyolefin fibers, particularly polypropylene fibers, have
required dyeing at pH values below 2.5 in order to obtain
satisfactory fastness to light, crocking, washing and alkaline
perspiration, i.e., properties dependent upon the structure of the
dye molecule and penetration of the dye molecule to the fiber.
Moreover, such dyeings also require a long dyeing cycle.
SUMMARY OF INVENTION
According to the present invention there is provided a process for
dyeing shaped articles based on polyolefins comprising:
1. forming a uniform blend of about 98 to 85 percent by weight of a
polyolefin and about 2 to 15 percent by weight of a thermoplastic,
compatible basic nitrogen-containing polymer into a shaped
article;
2. exposing the shaped article to an aqueous prescour solution
containing about 3 to 200 percent, on weight of shaped article, of
a scour material selected from the group consisting of hydrochloric
acid, sulfuric acid, sulfamic acid, sodium bisulfate, phosphoric
acid, p-toluene sulfonic acid, and sodium dihydrogen phosphate, at
a temperature within the range of about 80.degree. to 120.degree.
C.; and
3. exposing the prescoured shaped article to an acid dye bath
containing an acid dye, a premetallized dye, a disperse dye or
mixtures thereof, said bath having a pH within the range of 3 to
7.
There is also provided a preferred process for dyeing fibers based
on polypropylene comprising:
1. uniformly blending isotactic polypropylene with about 4 to 10
percent by weight of an ethylene copolymer of about 60 to 80
percent by weight ethylene and about 40 to 20 percent by weight of
an amino acrylate of the formula:
wherein R is hydrogen or methyl;
R.sup.1 is hydrogen or alkyl of one to three carbon atoms;
R.sup.2 is alkyl of one to three carbon atoms, or t-butyl where
R.sup.1 is hydrogen; and
A is alkylene of two to three carbon atoms;
2. extruding the uniform blend into fibers;
3. exposing the fibers to an aqueous prescour bath containing about
5 to 15 percent, on weight of fiber of sodium bisulfate and about
0.25 to 2 percent, on weight of fiber, of a non-ionic surfactant at
a temperature of about 80.degree. to 120.degree. C.; and
4. exposing the prescoured fibers to an acid dye bath containing an
acid dye, said bath having a pH within the range of about 3 to
7.
DETAILED DESCRIPTION OF INVENTION
Polyolefins are not dyeable by acid dyes since they lack basic
sites with which the dye may form a complex of low solubility. The
most important polyolefin for use in formation of fibers at this
time is isotactic polypropylene, which is rendered dyeable by the
process of the present invention, and is commercially available
from many sources. The polypropylene can contain the usual thermal,
oxidative and ultraviolet light stabilizers. Optionally, the
polypropylene can contain structural modifiers which do not provide
basic sites for acid dyes. Such modifiers would include
ethylene/vinyl acetate copolymers, hydrolyzed ethylene/vinyl
acetate copolymers, waxes, paraffin oils, polycaprolactams,
polycaprolactones, polyethylene oxides, or low molecular weight
materials which modify the crystallization behavior of the
composition.
Polypropylene is rendered dyeable by uniformly blending it into a
polypropylene composition with 2 to 15 percent by weight,
preferably 4 to 10 percent, of a thermoplastic, compatible
nitrogen-containing polymer. The nitrogen-containing polymer
provides basic sites which will form complexes with acid dyes. It
is important that the nitrogen-containing polymer be both
thermoplastic and compatible with polypropylene so that processing
difficulties are minimized or prevented. By the term compatible is
meant that the nitrogen-containing polymer does not separate into
discrete particles in the polypropylene composition which are
observable under an optical microscope at a magnification of 250
.times. to 500 .times.. Generally, the preferred polymers are
copolymers of ethylene with an amine or amide compound.
Preferred nitrogen-containing polymers are copolymers of ethylene
and an aminoalkyl acrylate compound as disclosed in U.S. Pat. No.
3,395,198. As therein described, the aminoalkyl acrylate compound
has the general formula:
wherein R.sub.1 is hydrogen or methyl radical;
each of R.sub.2 and R.sub.3 is hydrogen or alkyl radicals of one to
four carbon atoms; and
n is an integer of 1 to 4 inclusive
The copolymers contain 1 to 50 mole percent of the aminoalkyl
acrylate compound.
Particularly preferred copolymers are the random and homogeneous
copolymers of ethylene and aminoacrylate compounds disclosed in
U.S. Pat. application Ser. No. 834,196, filed June 2, 1969, in the
name of Clarence Frederick Hammer. These copolymers contain about
20 to 40 percent by weight of an amino acrylate of the formula:
wherein R is hydrogen or methyl;
R.sup.1 is hydrogen or alkyl of one to three carbon atoms;
R.sup.2 is alkyl of one to three carbon atoms or t-butyl when
R.sup.1 is hydrogen; and
A is alkylene of two to three carbon atoms.
These copolymers have a melt index of 1 to 3,000, preferably from
30 to 1,000; have a compositional inhomogeneity (U) as defined
therein of less than 0.3; and have a thermal stability such that
when the temperature is raised at 10.degree. C./min., under flowing
nitrogen, less than 0.75 percent of the copolymer weight has been
lost at 300.degree. C.
Typical examples of aminoacrylate compounds to be copolymerized
with ethylene are diethylaminoethyl acrylate or methacrylate,
dimethylaminoethyl acrylate or methacrylate, dimethylaminopropyl
acrylate or methacrylate, aminomethyl acrylate or methacrylate,
amino-n-butyl acrylate or methacrylate, N-t-butyl-aminoethyl
acrylate or methacrylate, or diisopropyl-aminoethyl acrylate or
methacrylate. The preferred aminoacrylate compound is
dimethylaminoethyl methacrylate. While the above copolymers of
ethylene and aminoalkyl acrylate are preferred, other thermoplastic
basic nitrogen-containing polymers that are compatible with
polypropylene can be used.
It is important in carrying out the dyeing procedure of this
invention that the polypropylene and nitrogen-containing polymer be
uniformly blended prior to forming the blend into a shaped article,
i.e., the fibers must be formed from a uniform blend. The blending
can be accomplished in a separate step prior to forming, or the
blending and extrusion can be carried out in the same operation if
the extruder has a suitable mixing section. Poor blending can
result in uneven dyeing even if the remaining steps of dyeing
procedure are properly conducted.
The uniform blend of polypropylene and nitrogen-containing polymer
is formed into the desired shaped article by any of the known
techniques such as melt spinning in the case of fibers, casting or
other known methods of film-making, extrusion or injection molding.
The present invention is particularly useful with fibers and it has
been found that fibers of various deniers can be adequately dyed
with good dye utilization and without excessive scour bleed-loss
and ring-dyeing. Generally, the fibers are from 1 to 1,500 denier
and can be in the form of round or lobed fibers, tape or
fibrillated film. Round or lobed fibers are for apparel, upholstery
and carpet face yarn uses and can have a denier of about 1 to 60
without encountering dyeing problems by the present technique.
These fibers can also be used in production of other articles, such
as decorated ribbons or non-woven textiles. The tape fibers are
generally used for carpet backing and are of heavier denier, i.e.,
about 500 to 1,500 denier. Fibrillated film fibers are used for
cordage, carpet face yarn or upholstery.
For fibers to be fully penetrated by dye, the spinning and drawing
processes should be conducted in a manner to produce a fiber with a
uniform structure through its cross-section i.e., minimal
sheath/core structural differences. On the other hand, greater
economy of dye use in dyeable carpet backing made from woven tapes
can be obtained if such tapes do possess a sheath/core structure.
In these sheath/core structures, the sheath is dyeable, while the
core exhibits very little dye pick-up. Thus, less dye is used to
dye a backing which is made up from such fibers.
After spinning of the fibers, but before drawing, a spin finish can
be applied to the fibers. If such a material is used, it should not
be anionic since such a finish may be deleterious to dyeing, but
preferably should be non-ionic in nature. Non-ionic spin finishes
are commercially available and a preferred one is "Nopcostat" 2152P
which is thought to be a modified coconut fatty acid ester.
Finishes which contain anionic surfactant components can affect
dyeing by acting as dye uptake rate retarders. Also, finishes
containing mineral oil can affect fiber physical properties, the
mineral oil acting as a plasticizer. This plasticization can
increase dye uptake rate at the fiber surface, but dye loss in a
post-scour step is increased. A water-dispersible or water-soluble
finish such as "Nopcostat" 2152P modified coconut fatty acid ester
is preferred.
Finishing operations can optionally be performed on the fibers
before dyeing. For example, the fibers can be texturized by
mechanically crimping or forming such as described in "Ingenuity
Spreads Texturizing--Rapidly," Modern Textiles Magazine, Aug. 1969,
page 21.
The next operation is extremely important to the final dyeing step.
The fibers are exposed to a dilute aqueous prescour solution
containing about 3 to 200 percent, on weight of fiber, of sodium
bisulfate, sulfamic acid, p-toluene sulfonic acid and sodium
dihydrogen phosphate as the scour material; however, a preferred
upper limit for economic reasons is 100 percent. It is especially
preferred that about 5 to 15 percent, on weight of fiber, of sodium
bisulfate be used as the scour material in an aqueous prescour bath
also having present about 0.25 to 2 percent, on weight of fiber, of
a non-ionic surfactant to assist in wetting and penetration. The
non-ionic surfactant can be added directly to the prescour bath or
it can be carried over on the fibers as the spin finish. Over 2
percent non-ionic surfactant can be present if it is carried over
as the spin finish and more added to the prescour bath. Non-ionic
surfactants are well known to those skilled in the art. These
surfactants and surfactants in general are shown in Detergents and
Emulsifiers, McCutcheon, 1969 annual, Allured Publishing Corp.,
Ridgewood, N.J. 07450. At the higher concentrations of scour
materials, the scour material itself can give a beneficial effect
without a non-ionic surfactant; however, the use of surfactant is
preferred. While aqueous mineral acids such as sulfuric,
hydrochloric, and phosphoric acids can be used in the prescour
solution, they are not preferred due to their corrosive action on
processing equipment, with the exception of phosphoric acid.
Conventional liquor to fiber ratios of 20:1 to 60:1 are most
convenient for carrying out this step.
The temperature of the prescour bath should be within the range of
about 80.degree. to 120.degree. C. and preferably at the boil
(about 100.degree. C.). Of course, the lower the temperature, the
longer the fibers must be in the bath. It is usually sufficient to
have the fibers in the bath 15 minutes at the boil. Elevated
temperatures achieved by operating at higher than atmospheric
pressure are also effective in achieving the desired results. An
upper temperature limit would be that at which fiber structure is
charged to adversely affect fiber dyeing or physical
properties.
The fibers are then dyed in an acid dye bath generally between pH 3
and pH 7 using conventional acid dyes and acid dyeing techniques.
While it is preferred to drain the prescour bath, rinse the fibers
and then make up the dye bath, the dye bath can be prepared from
the prescour bath if it does not contain excessive amounts of dirt,
spin finish, or surfactants. Use of the prescour prior to dyeing
enables the fibers to be acid dyed at pH levels heretofore
unattainable while obtaining good tinctorial strengths.
The pH level for the dyeing of round additive-modified polyolefin
fibers or fibrillated film fibers or tapes alone in the dyebath is
initially under 5, generally from 3 to 5 and usually around pH 4.
When dyeing round or flat fibers competitively with nylon (i.e., in
the same dyebath) as in a carpet consisting of a
nylon/polypropylene face yarn or in a carpet tufted with nylon and
backed with a polyolefin composition or in a fabric composed of a
blend of the two fibers the initial pH should be set between pH 6
and 7 and then dropped to a pH between 3 and 4 when the dyebath has
reached the boil. It is also preferred, when union dyeing a
polyolefin with nylon, that the dyebath containing non-ionic
surfactant (0.5 to 2.0 percent owf) which has some oleophilic
character to assist the dyeing of the polyolefin and also an
anionic surfactant (0.5 to 2.0 percent owf) to sufficiently retard
the dyeing rate of the nylon until higher temperatures are reached.
This procedure enables good shade depth and trueness of shade to be
obtained on both the nylon and the polyolefin when dyeing with a
single dye or with a compounded dye formulation consisting of as
many as 5 dyes. Also when dyeing a nylon carpet backed with
additive-modified polyolefin such as polypropylene, this procedure,
involving a sequential drop in pH, allows the dye to be levelly
applied across the width of the carpet.
When dyeing additive-modified polyolefin alone in the dyebath, the
anionic surfactant can be omitted. For best results and for good
dye penetration, the non-ionic surfactant (0.25 to 2.0 percent OWF)
can be optionally employed.
A carpet comprised of a polyester face yarn and an
additive-modified polypropylene backing can be dyed to a shade
match with formulated dye by using standard polyester dyeing
techniques. Ordinary polyester-type carriers are employed here.
Competitive dyeing of polyolefins is particularly important and
useful when dyeing styled carpets consisting of several different
fibers such as nylon, polyester, etc. and a polyolefin. Different
styling effects can be produced by controlling shade depth on each
type of fiber present. Acid, disperse and premetallized dyes or
combinations thereof, depending upon the fibers present, can be
employed to obtain styling effects. Also, styling effects obtained
from a fiber combination can be achieved by making a fabric or
carpet face from polyolefin yarns containing varying amounts of
nitrogenous polymer. Just as tweed effects can be produced in a
nylon carpet by tufting with nylon fibers containing different
levels of amine ends, so too can these styled, tweed effects be
produced in a polyolefin fiber by controlling the concentration of
dye sites. Print dyeing, space dyeing, and continuous dyeing can be
carried out with fabrics made from such yarns.
Any of the acid dyes known to those skilled in the art can be used
in the acid dye bath. There are many such dyes commercially
available. Also, commercially available premetallized dyes and
disperse dyes can be used in the dye bath.
An optional feature of the invention is the incorporation of a
carrier into either the prescour bath or acid dye bath to aid the
dye in penetrating difficult-to-dye fibers. It has been found that
carriers useful in dyeing polyesters, such as hydrocarbons or
chlorohydrocarbons are also useful in dyeing modified polypropylene
fibers. Several carriers are listed in Knitted Outerwear Times,
Aug. 24, 1964, page 21. Although not listed in the preceding
reference "Varsol", Stoddard solvent, and xylene are especially
preferred for the polypropylene. "Varsol" and Stoddard solvent are
hydrocarbon solvents commonly used in the textile trade for
prescour purposes. Other hydrocarbon solvents or naphthas having
boiling points ranging from 75.degree. to 200.degree. C. can be
used as carriers for the dyeing of the polypropylene. When used,
these carriers are emulsified in equal parts of water using about 5
percent of a non-ionic surfactant and then added at the beginning
of the dye cycle before the dye is added. While carriers are
optional in carrying out the process of the present invention, when
they are used it is essential that the polyester-type carrier be
pre-emulsified prior to use, Carriers are important for the
competitive dyeing of nylon and polypropylene with a disperse
dye.
The invention can be further understood by referring to the
following examples in which parts and percentages are by weight
unless otherwise indicated.
EXAMPLE 1
A polypropylene composition containing 93 percent by weight of a
commercial fiber grade of isotactic polypropylene having a melt
flow rate of 6.5 (ASTM D-1238-65 T, Condition L) and containing
thermal, oxidative and ultraviolet light stabilizers and 7 percent
by weight of a copolymer of ethylene dimethylaminoethyl
methacrylate was prepared by first dry mixing the polymers and then
melt blending the mix in a 1-inch Killion extruder at 200.degree.
C. The ethylene copolymer contained 30 percent by weight of the
aminomethacrylate comonomer, and had a melt flow rate of 300 (ASTM
D-1238-64 T, Condition E). The resulting homogeneous, compatible
polymer blend was cut into nibs after water-quenching, which were
then fed to an experimental melt spinning apparatus and 8 denier
per filament fiber was spun at 250.degree. C. A mineral-oil based
finish containing anionic surfactants was applied to the fiber
bundle after spinning, but before drawing. The fibers were drawn
3.times. over snub pins and a hot pipe to give a final denier of 8
per filament. The fibers were knitted on a latch-type circular
knitting machine to produce a tubular-knit fabric. Five-gram
samples of the fabric were dyed according to the procedure given
below. All steps were carried out using a 40:1 liquor-to-goods
ratio.
SAMPLE (A):
Prescour:
The sample was prescoured in a solution containing 1 percent (OWF)
of an oleyl alcohol ethylene oxide condensation product non-ionic
surfactant ("Merpol" HCS) for 20 min., at 80.degree. C., then
rinsed in clear water.
Dyeing:
Following the prescour, the sample was next immersed in a dye bath
containing 2 percent (OWF) "Merpacyl" Blue SW (C.I. Designation,
Acid Blue 25, CI62055) and 1 percent (OWF) of a sodium alkyl diaryl
sulfonate anionic dyeing assistant ("Alkanal" ND). The pH was
adjusted to 3.0 with formic acid. The temperature of the bath was
raised to the boil over a 1.5-hr. period and held for 3 hrs. The
percentage of dye uptake onto the fibers of the fabric sample was
measured colorimetrically at the end of the dyeing cycle, and found
to be 98 percent.
Postscour:
The fabric sample from the dyeing step was squeezed dry and
directly immersed into a postscour solution to determine the amount
of dye not firmly bound. The solution contained 0.8 percent (OWF)
of sodium lauryl sulfate anionic surfactant ("Duponol" D) and was
adjusted to pH 9.5 with sodium carbonate. A 20-min. period at
80.degree. C. was allowed for this postscour step. Colorimetric
analysis showed that scour loss for this dyeing was 33 percent.
The percentage dye utilization, i.e., percent dye uptake less
percent dye loss, was 65 percent. There was no change in dye
utilization by using a boiling water prescour (0.5 hr.) in place of
the surfactant-containing prescour set forth above.
SAMPLES (B) through (D) were dyed using the prescour, dyeing and
postscour procedures that were used with Sample (A) except the dye
baths were adjusted to initial pH values of 4.0, 5.0, and 6.0,
respectively.
SAMPLES (E) through (H) were dyed and postscoured in the same
manner as Samples (A) through (D); however, a different prescour
procedure was used. In this procedure, the samples were prescoured
for 1 hour at the boil with a 5 percent solution of sodium
bisulfate monohydrate (200 percent OWF of NaHSO.sub.4 .sup..
H.sub.2 O). The fabric samples were then dyed at pH values of 3, 4,
5 and 6, respectively.
SAMPLES (I) through (L) were prescoured, dyed and postscoured in
the same manner as Samples (E) through (H) except a 5 percent
solution of p-toluene sulfonic acid monohydrate was used as the
prescour.
SAMPLES (M) through (P) were prescoured, dyed and postscoured in
the same manner as Samples (E) through (H) except a 5 percent
solution of 85 percent orthophosphoric acid was used as the
prescour.
Dye utilization values of Samples (B) through (P) were determined
as with Sample (A) and these values are shown in Table I.
##SPC1##
Comparison of the above dye utilization data shows that Samples (E)
through (P) dyed by the procedure of the present invention have
much higher dye utilization values across the pH range of 3 to 6
than do Samples (A) through (D) dyed by a control procedure. For
Samples (E) through (P) it is noted that the dye utilization at pH
6 is substantially the same as the dye utilization of Sample (A)
dyed at pH 3. The greater dye utilization and the greater pH range
for satisfactory dyeing is of great economic value.
EXAMPLE 2
To screen other useful agents, the same fabric used in Example 1
was prescoured with 5.0 percent solutions of (A) sulfamic acid, (B)
sodium dihydrogen phosphate monohydrate, (C) ammonium sulfate, (D)
boric acid, and (E) sodium sulfate, for 0.5 hr. at the boil
followed by rinsing. Dyeings were carried out as in Example 1 at a
pH adjusted to 4.0 for these tests, and the samples postscoured as
in Example 1. The initial and final pH values of the prescour
solution, as well as the dye utilization data, are given in Table
II. These results show that improved dye utilization values are not
the result of only the acidity of the prescour bath, as measured by
pH. If this were the case, boric acid (initial pH 3.3) should have
given higher dye utilization values than did sodium dihydrogen
phosphate (initial pH 4.4) and sodium sulfate (initial pH 5.5).
##SPC2##
EXAMPLE 3
Using the prescour, dye bath and postscour of Samples (E) through
(H) of Example 1, the dye baths were adjusted to pH values of 3.0,
4.0, 5.0, and 6.0, and into these dye baths were immersed 5.0 g.
samples of the Example 1 fabric with an equal weight of nylon 66 --
a condensation product of hexamethylene diamine and adipic acid.
The nylon had been previously prescoured with 1 percent (OWF) of an
oleyl alcohol ethylene oxide condensation product non-ionic
surfactant ("Merpol" HCS). Following the dyeing and postscouring
steps, the modified polypropylene fabric and the nylon yarn were
found to be closely matched in shade.
EXAMPLE 4
To determine the minimum effective concentration and conditions for
the process of this invention, prescour solutions containing 1.0%,
0.5%, and 0.2% NaHSO.sub.4 .sup.. H.sub.2 O plus 0.1 percent
("Tergitol" 15-S-9) a polyethylene glycol ether of linear alcohol
non-ionic surfactant were made up. Using a 40:1 liquor-to-goods
ratio, the amounts of NaHSO.sub.4 .sup.. H.sub.2 O applied (OWF)
are 40, 20, and 8 percent, respectively, with 4 percent (OWF) of
surfactant. Using the polypropylene composition and spinning
conditions of Example 1, the spun yarn was then drawn 5.times. to
give 21 denier per filament material. Five-gram samples of this
fiber were prescoured in the above-described solutions for periods
of 15 min. and 30 min. at the boil. After rinsing, the fiber
samples were dyed at a pH of 4.0 using the dye bath and postscour
of Example 1. The results of these dyeings at pH 4 show that the
various prescour agent concentrations, time and temperature
conditions give, within experimental error, the same amount of dye
uptake and scour loss, the average values being 97 and 13 percent,
respectively, or a dye utilization value of 84 percent. In
contrast, a sample of the same fiber dyed by the procedure of
Sample (A) of Example 1 gives a dye utilization value of only 78
percent at a lower pH value of 3.0.
EXAMPLE 5
A. Twenty-four denier per filament polypropylene yarn modified with
7 percent of the ethylene copolymer additive described in Example 1
was spun using "Nopcostat" 2152P a modified coconut fatty acid
ester, non-ionic spinning finish and then knitted into a tubular
knit fabric. Four 5 g. samples of fabric were prescoured in a
solution containing 0.2% NaHSO.sub.4 .sup.. H.sub.2 O and 0.1%
sodium alkyl diaryl sulfonate anionic dyeing assistant ("Alkanol"
ND) for 30 min. at the boil, rinsed, and dyed at pH 4.0 for 2 hrs.
at the boil, using the following dyes, one sample for each dye
bath: (1) 2 percent (OWF) of "Merpacyl" Blue SW (C.I. Designation,
Acid Blue 25, C.I.6,2055), (2) 2 percent (OWF) of "Capracyl" Orange
R, a premetallized dye (C.I. Designation, Acid Orange 60), 93) 2
percent (OWF) of acid red dye "Merpacyl" Red G, (C.I. Designation,
Acid Red 337), and (4) 2 percent (OWF) of "Lanasyn" Brilliant
Yellow 5GL, a monoazo neutralized metallized dye (C.I. Designation,
Acid Yellow 127). Each sample was postscoured as in Example 1 and
the results of these dyeings and lightfastness tests of the samples
are shown in Table III. The lightfastness test was conducted and
rated in accordance with AATCC 16E-1964 entitled "Color Fastness to
Light, Water-Cooled Xenon Arc Lamp, continuously". A rating of 5 is
the top rating. As can be seen the lightfastness results are
outstanding. Photomicrographic cross-sections of fiber samples
showed that dye had penetrated to 50 percent of the fiber diameter
in these dyeings in which no surfactant or dyeing assistant was
used in the dyebath.
B. The same fabric of Example 5 (A) was prescoured by boiling in
water for 30 min., dyed with 2 percent (OWF) of "Merpacyl" Blue SW,
acid blue dye C.I. 62055 "Capracyl" Blue SW at pH 4.0 and then
postscoured as in Example 1. Photomicrographs of the fiber
cross-sections of this sample showed ring dyeing, i.e., the dye was
concentrated on the fiber surface. The data in Table III show that
scour loss is increased and lightfastness decreased by dyeing
according to this conventional procedure.
C. Another sample of the fabric of Example 5 (A), was prescoured as
in (A), but rather than rinsing the fabric, the scour solution was
adjusted to pH 4.0 with sodium hydroxide, 2 percent (OWF) of
"Merpacyl" Blue SW, acid blue dye C.I. 62,055 added, and the sample
dyed and postscoured as in Example 5 (A). The dye utilization value
and lightfastness for this sample is outstanding, and a
photomicrographic cross-section showed complete penetration of the
fiber by dye. This result shows that "Nopcostat" 2152 P, a modified
coconut fatty acid ester finish, applied to the fiber during
processing, did not deleteriously affect the dyeing behavior of the
fiber and, in fact, the non-ionic character of the finish greatly
aids in the dye penetration. ##SPC3##
EXAMPLE 6
Two other fabric samples of Example 5 (A) were prescoured
separately and in different solutions for 30 min. at the boil at a
40:1 liquor-to-goods ratio. The solutions were as follows: (A) 8
percent (OWF) of NaHSO.sub.4 and 1 percent (OWF) of "Alkanol" ND,
sodium alkyl diaryl sulfonate nionic dyeing assistant, and (B) with
8 percent (OWF) NaHSO.sub.4 .sup.. H.sub.2 O and 1 percent (OWF) of
a polyethylene glycol ether of linear alcohol non-ionic surfactant
("Tergitol" 15-S-9). Following rinsing, both samples were dyed
separately in baths containing 2% (OWF) of "Merpacyl" Blue SW (C.I.
Designation, Acid Blue 25, C.I.62055) and 1% (OWF) of a
polyethylene glycol ether of linear alcohol non-ionic surfactant
"Tergitol" 15-S-9. The temperature was raised to the boil over a 1
-hr. period and held at the boil for 2 hrs. Small fiber samples
were removed from the main sample when the dye bath reached the
boil, 1 hr. after the boil, and 2 hrs. after the boil.
Photomicrographic cross-sections of the fibers showed that the
sample prescoured by procedure (A) had fibers about 50 percent
penetrated by dye when the boil was reached, with little or no
increase in the amount of dye penetration after 1 hr. and 2 hrs. at
the boil. These results are similar to those obtained in Example 5
(A) (1).
In contrast, the sample prescoured by procedure (B), using a
solution containing non-ionic surfactant, had fibers greater than
50 percent penetrated by dye when the boil was reached, and about
100 percent penetration after 1 hr. at the boil. This example shows
the great advantage of using a non-ionic surfactant in the prescour
bath liquor.
EXAMPLE 7
Commercial isotactic polypropylene was blended with 7 percent of
the ethylene copolymer additive described in Example 1, and spun
into fiber at 250.degree. C. The spun fiber was wound up and
subsequently drawn 5.times. through a hot water bath to give yarn
composed of 20 denier per filament fibers. "Mopcostat" 2152 P, a
modified coconut fatty acid ester non-ionic spinning finish was
applied to the fibers after drawing. In a like manner, other
ethylene copolymer additives containing 20, 26, and 28 percent
dimethylaminoethyl methacrylate comonomer at 130, 300, and 140 melt
index, respectively, were blended with polypropylene and spun into
fibers. Dyeings were carried out as in Example 6 (B), except a
different polyethylene glycol ether of linear alcohol non-ionic
surfactant was used. "Tergitol" 15-S-7. While the ethylene
copolymer additive containing 20 percent comonomer gave a dye
utilization value of 58 percent, the others gave dye utilization
values of greater than 80 percent in these dyeings.
EXAMPLE 8
Competitive Dyeing 846 Nylon-Modified Polypropylene
A piece of carpeting tufted in a 5/1 ratio of face to backing with
nylon 66 (20 dpf) and backed with a woven polypropylene tape
backing (500 d.p.f.) containing 7 percent of the ethylene copolymer
additive as described in Example 1 was prescoured on a 6 inch dye
beck in an 8 percent (OWF) sodium bisulfate solution containing
0.75 percent (OWF) "Merpol" HCS of an ethylene oxide condensation
product of oleyl alcohol non-ionic surfactant for 15 min. at
90.degree. to 100.degree. C. A 40/1 liquor-to-goods ratio was
maintained throughout the prescour and the dye bath. The prescour
was drained and the beck was refilled with a solution containing
0.75 percent (OWF) "Duponol" D of a mixed sodium long-chain alcohol
sulfates anionic surfactant, 1.5 percent (OWF) of a fatty alcohol
ethylene oxide condensation product non-ionic surfactant "Merpol"
OE and 2.5 percent (OWF) sodium acetate. The pH of this solution
was between 6.6 and 6.8. The carpeting was run through the beck for
5 min. and the pH was reset with dilute Na.sub.2 CO.sub.3 solution.
A 2 percent (OWF) solution of "Merpacyl" Blue SW acid blue dye C.I.
62055 was evenly added to the beck. The temperature was programmed
to the boil (45 min.) at which time the pH was lowered to 3.0 with
5% NaHSO.sub.4 solution. The boil was maintained for 2 hrs. The dye
bath was then drained and the beck was refilled and the carpeting
rinsed well with distilled water. The carpet was dried at
120.degree. C. in a forced air oven. The color obtained on both the
nylon face yarn and the modified polypropylene backing was
essentially the same.
To illustrate the advantage of a compatible basic
nitrogen-containing polymer, competitive disperse dyeing of
polyester or nylon with the modified polypropylene was carried out
using a standard polyester disperse dyeing procedure. A piece of
carpeting tufted in a 5/1 ratio of face to backing with "Enkron"
polyester American Enka, 20 d.p.f.) and backed with a woven
polypropylene tape backing (500 d.p.f.) containing 7 percent of the
Example 1 ethylene copolymer additive was prescoured on a 6 inch
dye beck in a solution containing 1.5 g./l. of an ethylene oxide
condensation product of oleyl alcohol "Merpol" HCS non-ionic
surfactant ("Merpol" HCS) and 1.5 g./l. tetrasodium pyrophosphate
as a buffer at 70.degree. to 80.degree. C. for 15 min. For disperse
dyeing, a scour material is not essentially in the prescour
solution. A 30/1 liquor-to-goods ratio was maintained throughout
the prescour, dye bath and the postscour. The prescour was drained
and the beck was refilled with a solution containing 0.5 percent
(OWF) of a fortified sodium ethylene oxide condensate non-ionic
surfactant ("Merpol" DA), 1.0 percent (OWF) anionic hydrocarbon
sodium sulfonate surfactant ("Avitone" T) and the dye formulation
consisting of the following disperse dyes:
0.20 percent (OWF) C.I. Disperse Yellow ("Latyl" Yellow 3G) 54
1.00 percent (OWF) C.I. 26070 ("Latyl" Yellow 4RL
0.05 percent (OWF) C.I. Disperse Blue 62 ("Latyl" Blue LS)
The beck was run up to 75.degree. C. at a pH 6.0. A
self-emulsifiable carrier (6 percent OWF) of the biphenyl type
("Carolid" 3F-Tanatex) was added at this point. The dye bath was
then held at the boil for 1.5 hrs. The dye bath was drained and the
carpet was postscoured with a solution containing 1.0 g./l.
Na.sub.2 CO.sub.3 and 1 percent (OWF) of an ethylene oxide
condensation product of oleyl alcohol non-ionic surfactant
("Merpol" HCS) for 15 min. at 70.degree. C. The carpet was then
rinsed well with water and dried at 120.degree. C. in a forced air
oven. The color obtained on both the polyester face yarn and the
modified polypropylene backing was essentially the same.
A piece of carpeting tufted in a 5/1 ratio of face to backing with
nylon 66 (DuPont 20 d.p.f.) and backed with a woven polypropylene
tape backing (500 d.p.f.) containing 7 percent of the Example 1
ethylene copolymer additive was prescoured in a 1 percent (OWF)
solution of an ethylene oxide condensation product of oleyl alcohol
non-ionic surfactant ("Merpol" HCS) for 15 min. at 70.degree. C. As
with the polyester above, a scour material is not needed in the
prescour solution for disperse dyeing. A 40/1 liquor-to-goods ratio
was maintained throughout the prescour, the dye bath and the
postscour. The prescour was drained, the carpeting was rinsed with
water and placed in a dye bath containing 0.5 percent (OWF) of a
fortified sodium ether-alcohol sulfate anionic surfactant
("Duponol" RA) 2 percent (OWF) of a yellow disperse dye -- "Latyl"
Yellow 3 G, and 25 percent (OWF) of a 50 percent aqueous emulsion
of "Varsol" prepared as described in Example 9. The temperature was
raised to the boil (1 hr.) and held there for 2 hrs. The carpet was
then postscoured well with a solution containing 1 percent (OWF) of
a fortified sodium ether-alcohol sulfate anionic surfactant
("Duponol" RA) at 80.degree. C. for 15 min., at which time the
sample was rinsed well with water and dried at 120.degree. C. in a
forced air oven. The color of both the nylon face and modified
polypropylene backing was essentially the same.
EXAMPLE 9
Carrier Dyeing
Loose, isotactic polypropylene round fibers (22 d.p.f.) (containing
7 percent of the ethylene copolymer additive of Example 1 ) were
prescoured in an 8 percent (OWF) sodium disulfate solution for 15
min. at 90.degree. to 100.degree. C. The liquor-to-goods ratio was
maintained at 40/1 throughout the prescour, dye bath and postscour.
The fibers were rinsed and samples were placed in separate dye
baths containing 2 percent (OWF) "Merpacyl" Blue SW (C.I. Acid Blue
25, C.I.62055) and from 5 to 20 percent (OWF) of one of the
following pre-emulsified carriers: a biphenyl type - "Carolid" 3F
(Tanatex); butyl benzoate - DAC 888 (Cindet); methyl naphthalene; a
biphenyl type - "Chemcryl" KCD (Chem. Proc. of Georgia); a modified
ester type - "Carolid" PSS (Tanatex), and trichlorobenzene. It is
essential for best results that the carrier be of the
pre-emulsified variety as are those listed. It was also found that
emulsions prepared by mixing 50 weight percent of an aqueous
solution of xylene, toluene or "Varsol" hydrocarbon solvent (Esso)
with 5 percent of an octyl phenoxy polyethoxy ethanol non-ionic
surfactant ("Triton" X-100) could also be used quite effectively as
carriers. Sodium acetate (2.5 percent OWF) was also added as a
buffer. The pH of the baths were set at 4 with acetic acid and then
taken to the boil over a 1-hr. period. The baths were held at the
boil for 2 hrs., at which time the fibers were removed and
postscoured with a solution containing 0.8 g./l. of mixed sodium
long-chain alcohol sulfates non-ionic surfactant ("Duponol" D) (pH
9.5 Na.sub.2 CO.sub.3) for 15 min. at 75.degree. to 80.degree. C.
The color in all dyed fibers was uniform and the fibers were fully
penetrated to the center. Best results were obtained by using
xylene or "Varsol" emulsions and with "Larasol" DP methyl
naphthalene, "Carolid" 3 F and "Chemcryl" KCD.
EXAMPLE 10
Dyeing of Fibrillated Film Fiber
Loose, isotactic polypropylene fibrillated film fiber containing 7
percent of the ethylene copolymer additive described in Example 1
was prescoured in an 8 percent (OWF) sodium bisulfate solution for
15 min. 90.degree. to 100.degree. C. The liquor-to-goods ratio was
maintained at 40/1 throughout the prescour, dye bath and postscour.
The fibers were rinsed and placed in a dye bath containing 2
percent (OWF) acid blue dye C.I.62055. "Merpacyl" Blue SW. Sodium
acetate (2.5 percent OWF) was added as a buffer to the dye bath.
The pH was set at 4 with acetic acid and the bath taken to the boil
over a 1-hr. period. The bath was held at the boil for 2 hrs., at
which time the fibers were removed and postscoured with a solution
containing 0.8 g./l. of mixed sodium long-chain alcohol sulfates
non-ionic surfactant ("Duponol" A) (pH 9.5 Na.sub.2 CO.sub.3) for
15 min. at 25.degree. to 80.degree. C. Adding about 5 percent of a
50 percent aqueous emulsion of "Varsol" to the dye bath increased
the dye utilization.
* * * * *