U.S. patent number 3,640,675 [Application Number 04/706,605] was granted by the patent office on 1972-02-08 for preparing permanent press garments by treating with composition therefor.
Invention is credited to Manuel A. Thomas.
United States Patent |
3,640,675 |
Thomas |
February 8, 1972 |
PREPARING PERMANENT PRESS GARMENTS BY TREATING WITH COMPOSITION
THEREFOR
Abstract
A fabric having been impregnated with a composition comprising a
neoprene elastomer, a polyisocyanate, polyisothiocyanate, blocked
derivatives and mixtures thereof, and a metal oxide are found to
have a propensity for subsequent durable dry setting in a
preselected configuration. Fabrics which have been prepared and set
in this manner exhibit improved crease retention, flat dry
stability and resistance to shrinkage even when subjected to home
laundering operation.
Inventors: |
Thomas; Manuel A. (Spartanburg,
SC) |
Family
ID: |
24838312 |
Appl.
No.: |
04/706,605 |
Filed: |
February 19, 1968 |
Current U.S.
Class: |
8/115.6;
8/DIG.11; 8/127.6; 8/193; 427/393.2; 8/115.7; 8/192; 38/144;
427/401 |
Current CPC
Class: |
D06M
15/693 (20130101); Y10S 8/11 (20130101) |
Current International
Class: |
D06M
15/693 (20060101); D06m 015/28 (); D06m
015/50 () |
Field of
Search: |
;8/116.2,115.6,115.7
;117/139.5,DIG.7 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
573,932 |
|
Dec 1945 |
|
GB |
|
1,371,652 |
|
Jul 1964 |
|
FR |
|
Primary Examiner: Levy; Donald
Assistant Examiner: Ives; Patricia C.
Claims
That which is claimed is:
1. A process for preparing garments having improved permanent press
characteristics which comprises
a. treating a textile fabric with a composition comprising
i. a polychloroprene or a copolymer of chloroprene with
acrylonitrile,
ii. an isocyanate compound selected from the group consisting of
polyisocyanates, polyisothiocyanates, adducts of said isocyanates
with compounds possessing only one group containing a reactive
hydrogen atom and mixtures of said isocyanates or adducts of
isocyanates, and
iii. a metal oxide selected from the group consisting of the oxides
of the group II metals, iron, lead and titanium;
b. converting the treated fabric into a garment;
c. maintaining the garment in a desired configuration; and
d. subjecting the garment to a temperature sufficient to cure the
treated fabric.
2. The process of claim 1 wherein the metal oxide is zinc
oxide.
3. The process of claim 1 wherein the textile fabric is treated
with an aqueous dispersion of the composition, and the isocyanate
compound is an isocyanate adduct.
4. The process of claim 1 wherein the composition comprises from
about 8 to 12 parts of polychloroprene, from about 1 to 5 parts of
the isocyanate compound and from about 0.2 to 1 part of the metal
oxide.
5. The process of claim 4 wherein the isocyanate is an alkylene
diisocyanate.
6. The process of claim 1 wherein the textile fabric is a fabric
containing at least some natural fibers.
7. A process for preparing garments having improved permanent press
characteristics which comprises
a. impregnating a textile fabric with a composition comprising
i. a chloroprene polymer or a copolymer of chloroprene with
acrylonitrile,
ii. an adduct of a polyisocyanate with a compound having only one
group containing a reactive hydrogen atom, and
iii. a small amount of zinc oxide, magnesium oxide or calcium
oxide;
b. drying the treated fabric;
c. converting the treated fabric into a garment;
d. maintaining the garment in a desired configuration; and
e. subjecting the garment to a temperature sufficient to cure the
treated fabric.
8. The process of claim 7 wherein the polyisocyanate adduct is an
aryl diisocyanate adduct.
9. The process of claim 7 wherein the metal oxide is zinc
oxide.
10. The process of claim 7 wherein the composition also contains an
antioxidant and an acrylic polymer.
Description
BACKGROUND OF THE INVENTION
This invention relates to a process for improving characteristics
of textile fibers, and more particularly, to the preparation of
fabrics having a propensity for subsequent durable dry setting.
Garments containing creases which are durable to home laundering
operations are known in the art. Garments prepared from cellulosic
fiber-containing fabrics having home laundry durable creases set
therein have recently found wide acceptance in the industry.
Cellulosic garments of the above-mentioned types and the methods
for their preparation are set forth in U.S. Pat. No. 2,974,432.
Satisfactory processes for the preparation of durable creases in
wool fabrics which will stand home laundering operations also have
been known, but these processes generally involve some form of wet
chemical treatment at the time of setting. For example, one type of
wool fabric known to be useful in the preparation of garments
having creases durable to home laundering operations is subjected
to certain chemical and physical treatments in fabric form, cut and
formed into a garment, and thereafter subjected to additional
chemical treatments prior to setting. Such a procedure requires
that the cutter and garment manufacturer maintain skilled personnel
and special equipment for the treatment of these fabrics prior to
setting. For these reasons, such methods for preparing permanent
press wool fabrics have not been completely accepted in the
industry.
Another method for preparing durable creases in natural
fiber-containing fabrics has involved the use of blends of
thermoplastic fibers and natural fibers such as cotton and wool. By
setting the thermoplastic component of the fabric at temperatures
near the melting point of the thermoplastic fiber, a crease is
produced which has a certain degree of durability to home
laundering operations. However, the setting operation generally
destroys the desirable hand and surface effects of the fabrics.
Still another method involves a three-blend fabric containing for
example, 50 percent wool, 40 percent rayon, and 10 percent nylon
wherein the rayon component is reacted with a typical postcured
resin such as dihydroxy dimethyl ethylene urea and subsequently
pressed and cured in an oven.
SUMMARY OF THE INVENTION
These problems have been overcome by providing textile fabrics
having a propensity for subsequent durable setting which have been
impregnated with a composition comprising a neoprene elastomer, a
compound selected from the class consisting of polyisocyanates;
polyisothiocyanates, blocked derivatives and mixtures thereof, and
a metal oxide. These impregnated fabrics may then be cut, converted
into a garment, maintained in a desired configuration, and
thereafter subjected to a temperature sufficient to cure the
impregnated fabric. The curing is a dry curing process thereby
eliminating any necessity for the cutter and garment manufacturer
to further treat the garment before it is pressed in its permanent
configuration.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The textile fabrics which are useful in this invention may be
prepared from virtually all types of fibers ranging from fabrics
containing 100 percent natural fibers such as cotton or wool to
fabrics composed exclusively of synthetic fibers such as polyesters
and polyamides. Blends of these fibers also have been valuable for
preparing garments having durable creases. Further examples of
fabrics include those containing natural fibers such as flax,
ramie, alpaca, vicuna, mohair, cashmere, guanaco, camel hair,
llama, fur, suede and silk. Synthetic fibers include polyamides
such as polyhexamethylene adipamide; polyesters such as
polyethylene terephthalate; acrylic fibers such as
polyacrylonitrile, homopolymers or copolymers of acrylonitrile,
such as acrylonitrile/methylacrylate (85:15); and cellulosic
derivatives such as cellulose acetate and viscose rayon. The
invention is particularly adapted to wool fabrics which heretofore
have been particularly difficult to set by post curing in a
preselected configuration durable to home laundering.
Examples of fabrics wherein synthetic fibers are blended with
natural fibers include wool/nylon (85:15); Acrilan/wool (55:45);
Orlon/wool (65:35); Dacron/wool (55:45); wool/rayon (65:35); and
wool/rayon/nylon (65:25:10).
Laminated fabrics are also susceptible to improvement by this
invention. The laminated fabrics can be composed of two or more
layers of fabric bonded together with an adhesive. Such laminated
fabrics are well known in the art. The outer layer is generally a
woven or knitted fabric comprised of natural fibers, synthetic
fibers or blends thereof. Examples of such fibers and fabrics have
been listed above. The inner or backing layer of the laminated
fabric is preferably a knitted fabric obtained from spun or
continuous filament yarns. Particularly useful and popular knitted
fabrics include those prepared from such fibers as cotton, nylon,
polyester, cellulose acetate, rayon and viscose rayon. Knitted
tricot fabrics such as acetate and nylon tricot have achieved wide
popularity.
The neoprenes useful in the composition of this invention are
chloroprene based synthetic elastomers. These may be either
polymers of chloroprene or copolymers of chloroprene with other
polymerizable ethylenically unsaturated compounds, such as
acrylonitrile. Copolymerization is generally catalyzed by a
potassium persulfate catalyst. The progress of the polymerization
is followed by means of specific gravity changes. Depending upon
the type of neoprene latex desired, a shortstop may be added after
the desired conversion has been obtained, or the polymerization may
be carried to completion.
In this manner, a wide variety of neoprenes can be prepared.
Examples of solid neoprenes which are available commercially
include the "sulfur-modified" types, such as Neoprene Type GN (a
sulfur-modified chloroprene polymer stabilized by a thiuram
disulfide), Neoprene Type GN-A (a sulfur-modified chloroprene
polymer stabilized by a thiuram disulfide and containing a
secondary aromatic amine stabilizer), Neoprene Type GRT (a
sulfur-modified chloroprene polymer stabilized by a thiuram
disulfide and containing a nondiscoloring antioxidant), and
Neoprene Type W, (a nonsulfur-modified general-purpose type of
neoprene). Although both the GN and W-Types are made by emulsion
polymerization chloroprene, the W-Type of neoprene has a more
uniform molecular structure and does not contain sulfur or other
compounds capable of decomposing to yield free sulfur. As a result
of these differences, Type W neoprene displays improved storage
ability and better processing properties. Magnesia and zinc oxide
are required modifying agents in all neoprene Type W
formulations.
Neoprene-Type Q is a copolymer of chloroprene and acrylonitrile
stabilized with a thiuram disulfide and containing a nondiscoloring
antioxidant. These and other neoprenes are described in more detail
in the book entitled The Neoprenes, Principals of Compounding and
Processing by Neil L. Catton, published in 1953 by E. I. duPont de
Nemours and Co., Wilmington, Del.
Neoprene latices are extremely useful in the preparation of the
compositions of this invention, especially in the preparation of
aqueous dispersions or emulsions of the compositions. The neoprene
latices are emulsions of polymerized chloroprene or copolymers of
chloroprene in water, which contain emulsifying agents and
stabilizers. The latices are milklike liquids containing from about
35 to 60 percent total solids. These latices are further
characterized in that they do not tend to settle out significantly,
even though the neoprene polymer has a specific gravity
considerably higher than that of the liquid in which it is
suspended. The different types of neoprene latices currently
available are obtained by varying certain manufacturing procedures
including the emulsification, catalyst and modifier systems.
Resulting latices differ from one another in polymer and colloidal
properties. A variety of neoprene latices are available from the E.
I. duPont de Nemours and Co. and several of these are described in
the book entitled Neoprene Latex, Principals of Compounding and
Processing, by John C. Carl, 1962. Examples of such neoprene
latices include Neoprene Latex 400 (a high modulus and ozone
resistant latex containing about 50 percent solids having a
Brookfield viscosity of 15 c.p.s.), Neoprene Latex 750 (a
low-modulus latex which is highly resistant to crystallization;
contains about 50 percent solids and has a Brookfield viscosity of
13 c.p.s.). Neoprene Latex 650 is a concentrated form of Latex 750
containing about 60 percent solids and having a Brookfield
viscosity of 4,000 c.p.s. An Example of a latex emulsion containing
a copolymer of chloroprene and acrylonitrile is Neoprene Latex 450.
The copolymer is highly oil resistant and noncrystallizing.
The particular solid neoprene or neoprene latex chosen for the
preparation for the compositions of the invention will depend upon
the relationship of the properties of the neoprene and those
desired of the fabrics treated with the composition. This selection
will be apparent to those skilled in the art.
The compositions of this invention also contain a compound selected
from the class consisting of polyisocyanates, polyisothiocyanates,
blocked derivatives or mixtures thereof. Polyisocyanates and
blocked polyisocyanates are preferred.
The suitable isocyanates that are useful in accordance with this
invention include, for example, aryldiisocyanates, such as
2,4-toluene diisocyanate, 2,6-toluene diisocyanate,
4,4'-diphenylmethane diisocyanate, p-phenylene diisocyanate,
1,5-naphthylene diisocyanate, m-phenylene diisocyanate,
diphenyl-4,4'-diisocyanate, 1-isopropylbenzene-3,5-diisocyanate,
1-methyl-phenylene-2,4-diisocyanate, naphthylene-1,4-diisocyanate,
diphenyl-4,4'-diisocyanate, 5-nitro-1, 3-phenylene diisocyanate,
xylylene-1, 4-diisocyanate, xylylene-1,3-diisocyanate,
4,4'-diphenylenemethane diisocyanate, 4,4'-diphenylenepropane and
diisocyanate; alkylene diisocyanates such as tetramethylene
diisocyanate and hexamethylene diisocyanate; as well as mixtures
thereof and including the equivalent isothiocyanates. Of these
compounds, the aryldiisocyanates are preferred because of their
solubility and availability.
Additional isocyanates include polymethylene diisocyanates and
diisothiocyanates, such as ethylene diisocyanate, dimethylene
diisocyanate, dodecamethylene diisocyanate, hexamethylene
diisocyanate, tetramethylene diisocyanate, pentamethylene
diisocyanate, and the corresponding diisothiocyanates; alkylene
diisocyanates and diisothiocyanates such as
propylene-1,2-diisocyanate, 2,3-dimethyltetramethylene diisocyanate
and diisothiocyanate, butylene-1,2-diisocyanate,
butylene-1,3-diisothiocyanate, and diisothiocyanates such as
ethylidene diisocyanate (CH.sub.3 CH(NCO).sub.2) and heptylidene
diisothiocyanate (CH.sub.3 (CH.sub.2).sub.5 CH(CNS).sub.2);
cycloalkylene diisocyanates and diisothiocyanates such as
1,4-diisocyanatacyclohexane, cyclopentylene-1,3 -diisocyanate, and
cyclohexylene-1,2-diisothiocyanate; aromatic polyisocyanates and
polyisothiocyanates such as phenylethylene diisocyanate (C.sub.5
H.sub.6 CH(NCO)CH.sub.2 NCO); diisocyanates and diisothiocyanates
containing heteroatoms such as SCNCH.sub.2 OCH.sub.2 NCS, and
SC(H)(CH.sub.2).sub.3 --S--(CH.sub.2).sub.3 NCS
1,2,3,4-tetraisocyanatobutane, butane-1,2,2-triisocyanate,
toluylene-2,4,6-triisocyanate, toluylene-2,3,4-triisocyanate,
benzene-1,3,5-triisocyanate, benzene-1,2,3 -triisocyanate,
1-isocyanate-4-isothiocyanatohexane, and
2-chloro-1,3-diisocyanatopropane.
The isocyanates or isothiocyanates may be derived from the
corresponding blocked compound in accordance with conventional
technology. Blocked isocyanates contain little or no free
isocyanate groups as the result of the additon onto these groups by
active hydrogen compounds (as determined by the Zerewitinoff
method). These addition products are relatively inert at room
temperatures but have only limited thermal stability. Thus upon
heating beyond a certain temperature, called the dissociation
temperature, the addition product is activated, or freed and takes
part in the curing process.
In the preparation of the adducts, the polyisocyanate and the
adduct forming compound are usually dissolved in a suitable inert
solvent such as toluene, methyl ethyl ketone, or o-dichlorobenzene.
The solutions are stirred together and permitted to stand. The
reaction should be caused to take place at a temperature below the
decomposition temperature of the desired product and preferably at
a temperature not exceeding approximately 100.degree. C. In most
instances, the reaction will proceed satisfactorily at room
temperature. When the solvent used for the isocyanate compound and
blocking agent is not also a solvent for the adduct formed, the
adduct formed separates from the solution and is removed therefrom
by filtration or evaporation of the solvent. The time required for
the adduct to form will vary from a few minutes to several hours
depending upon the particular reactants used. The precipitated
product will probably contain small amounts of unreacted material
which, if necessary, can be removed by recrystallization or
extraction procedures known to those skilled in the art.
Preferred adduct-forming compounds produce adducts which may be
activated, or unblocked, by heat alone. Typical active hydrogen
compounds which provide heat-reversible adducts include the
following:
1. Tertiary alcohols, such as tertiary butyl alcohol, tertiary amyl
alcohol, dimethyl ethinyl carbinol, dimethyl phenyl carbinol,
methyl diphenyl carbinol, triphenyl carbinol, 1-nitro tertiary
butyl carbinol, and 1-chloro tertiary butyl carbinol;
2. Secondary aromatic amines which contain only one group having a
hydrogen reactive with an isocyanate group, such as the diaryl
compounds, including diphenyl amine, o-ditolyl amine, m-ditolyl
amine, p-ditolyl amine, N-phenyl toluidine, N-phenyl xylidine,
phenyl alpha naphthyl amine, phenyl beta naphthyl amine, carbazole,
and the nuclear substituted aromatic compounds such as 2,2'-dinitro
diphenyl amine and 2,2'-dichloro diphenyl amine;
3. Mercaptans, such as 2-mercaptobenzothiazole, 2-mercapto
thiazoline, dodecyl mercaptan, ethyl 2-mercapto thiazole, dimethyl
2-mercapto thiazole, beta naphthyl mercaptan, alpha naphthyl
mercaptan, phenyl 2-mercapto thiazole, 2-mercapto
5-chloro-benzothiazole, methyl mercaptan, ethyl mercaptan, propyl
mercaptan, butyl mercaptan, and ethinyl dimethyl thicarbinol;
4. Lactams, such as epsilon-caprolactam, deltra-valerolactam,
gamma-butyrolactam, and beta-propiolactam;
5. Imides, such as carbimide, succinimide, phthalimide,
naphthalimide, and glutarimide;
6. Monohydric phenols in which the hydroxyl group is the only group
containing hydrogen reactive with the isocyanate group, such as the
phenols, cresols, xylenols, trimethyl phenols, ethyl phenols,
propyl phenols, chloro phenols, nitro phenols, thymols, mono alpha
phenyl ethyl phenol, di alpha phenyl ethyl phenol, tri alpha phenyl
ethyl phenol and tertiary butyl phenol;
7. Compounds containing enolizable hydrogen, such as acetoacetic
esters, diethyl malonate, ethyl n-butyl malonate, ethyl benzyl
malonate, acetyl acetone, acetonyl acetone and benzimidazole.
The adduct-forming compounds, should, of course, possess only one
group containing a reactive hydrogen atom. The presence of more
than one such group would permit polymerization reactions with the
polyisocyanate which are not desired in most instances. Among the
more preferable adduct-forming compounds are included diphenyl
amine and phenol.
The use of such blocked polyisocyanates is preferred in this
invention for a number of reasons which are based on the fact that
the blocked isocyanates are not reactive under normal conditions.
The selection of such blocked isocyanates permits the use of water
as the dispersing medium and avoids the necessity of utilizing
organic solvents. Moreover, the use of blocked isocyanates permits
the preparation of stable compositions regardless of the solvent
and enables one to prepare fabrics having a propensity for
subsequent durable setting several months after treatment without
any further chemical treatment. For example, as further illustrated
elsewhere in this application, a fabric can be converted into a
garment and set in a given configuration by dry heating and
pressing months after the fabric has been impregnated with the
compositions of this invention containing a blocked polyisocyanate.
Of course, the heating and pressing temperatures must be above the
dissociation temperature of the blocked isocyanate.
A third essential ingredient in the compositions of the invention
is a metal oxide such as zinc oxide, magnesium oxide (e.g.,
magnesia), litharge red lead (lead tetraoxide), calcium oxide, iron
oxide and titanium dioxide. The metal oxides perform three
important functions in the compositions of the invention. They
promote cross-linking or curing of the composition; they improve
resistance to aging, heat, light and weather; and they further act
as acid acceptors. The preferred metal oxide is zinc oxide although
a combination of magnesium and zinc oxide is desirable and
virtually necessary in compositions containing certain neoprenes,
such as, for example, Neoprene-Type GN.
Generally, about 5 parts of metal oxide per 100 parts of neoprene
provide satisfactory results although greater or smaller amounts
may also be utilized. For example, in some instances, as much as 10
parts of the metal oxide may be incorporated, and higher amounts,
from 10 to 15 parts, are often recommended in stocks requiring
maximum heat resistance although the use of such large quantities
results in products having somewhat reduced storage stability. Less
than 5 parts per 100 is sometimes used in transparent products in
order to reduce the pigmenting effect although such products should
not be used in intimate contact with acid sensitive materials.
It is possible in some instances to obtain a significant amount of
curing in the absence of a metal oxide if a zinc-containing
accelerator is used. Examples of such accelerators include the zinc
salt of 2-mercaptobenzothiazole or zinc dibutyl dithiocarbamate.
Products utilizing these accelerators should, however, be used with
caution since their aging resistance will be below that obtained
from the metal oxides.
Although the compositions comprising a neoprene elastomer, a metal
oxide, and a polyisocyanate or polyisothiocyanate may be applied as
prepared to a fabric, it is often desirable that the composition be
diluted with a liquid which is relatively inert to the
compositions. That is, the compositions should be either prepared
or added to a liquid to form solutions, dispersions or emulsions of
the composition. The amount of liquid is not critical except that
the viscosity of the solution, dispersion or emulsion should be
sufficiently low to permit the solution to impregnate the fabric.
Maximum benefit is obtained when the composition of the invention
impregnates the fabric as opposed to the deposition of a coating on
the fibers of the fabric. For this reason, Brookfield viscosities
of less than 5,000 centipoises are desirable and preferred.
The liquid utilized in the preparation of the solutions,
dispersions, or emulsions of the invention may be either
nonreactive organic solvents or in some instances, as explained
further below, water. By "nonreactive" solvents as used herein is
meant a solvent in which reactivity between the isocyanate and the
neoprene or the fabric, even in the presence of a catalyst, is
substantially inhibited.
Suitable organic solvents include halogenated hydrocarbons, such as
trichloroethylene, methylene chloride, perchloroethylene, ethylene
dichloride, and chloroform; aromatic solvents such as toluene,
xylene, benzene and mixed aromatics such as the Solveseso types,
n-butyl acetate, p-dioxane and methyl isobutyl ketone. Mixtures of
such solvents may also be used.
The use of a nonreactive organic liquid permits the combination of
all of the desired components of the composition in a single
solution, emulsion or dispersion without any substantial reaction
occurring among the components. In this manner, all of the
components, including the cure accelerators are impregnated
uniformly in the fabric in controllable amounts.
The use of water as a diluent or dispersing agent for the
compositions of the invention is limited to those compositions
wherein the isocyanate or isothiocyanate has been prereacted with
one of the adduct-forming compounds described previously to form a
blocked isocyanate or blocked polyisothiocyanate. Blocking of the
reactive isocyanate groups is essential since these groups react
readily with water if not blocked thereby eliminating their utility
in the aqueous compositions of the invention. As mentioned
previously, the compositions of this invention which contain the
blocked isocyanates or isothiocyanates provide especially desirable
results since these compositions may be impregnated into the fabric
and dried without substantial reaction among the components of the
composition and the fabric substrate. Reaction only occurs when the
impregnated fabric is heated to a temperature which is sufficient
to unblock or dissociate the blocked isocyanate which is then free
to react. Until the impregnated fabric is heated to such a
temperature, the fabric is in a presensitized state having a
propensity for subsequent permanent pressing. The fabric
presensitized in this manner is further characterized by excellent
stability and shelf life, and the ability to be set in a given
configuration in the dry state by heat alone. That is, the fabric
need not be wet by water or any other liquid or reactant to develop
the desirable permanent press characteristics.
Although the compositions described above are, in themselves,
useful, they nevertheless are susceptible to improvement by the
incorporation of other additives which impart properties desired
for special applications and needs. Such additives include
antioxidants, acrylic resins, polyhydroxy compounds, alkyd resins,
thermosetting resins such as phenolic resins, melamine resins and
urea formaldehyde resins, formaldehyde donors, silicones and
wetting agents. The type, number and amount of these optional
additives included in the compositions of the invention will depend
upon the particular properties desired.
Neoprene-containing compositions have been found to age in the
presence of air due to the slow attact by oxygen. Such aging
results in a reduction of the desirable physical properties. This
process is catalyzed further by heat and sunlight. Therefore, the
use of efficient antioxidants is desirable if not essential in
neoprene-containing compositions in order to assure outstanding
resistance to aging. The antioxidants should be selected with care
since they are not equally effective as antioxidants, and some have
some undesirable secondary effects such as increased discoloration
upon exposure to light or staining of the finishes. The more
effective antioxidants generally cause discoloration or staining.
The most commonly used antioxidants for black or dark-colored
stocks are the amine-type antioxidants such as those available
under the trade name "Neozone". Neozone A
(N-phenyl-1-naphthylamine) and Neozone D
(N-phenyl-2-naphthylamine), are examples of such amine
antioxidants.
In light-colored or nonstaining neoprene-containing compositions,
the use of suitable nondiscoloring antioxidants is recommended. The
substituted or hindered phenols are the most widely used
antioxidants of this class and generally give good aging properties
combined with maximum resistance to discoloration and staining.
Examples of such hindered phenols include "Antioxidant 2246" which
is 2,2'-methylene-bis(4-methyl-6-t-butylphenol) and "Antioxidant
425" which is 2,2' -methylene-bis(4-ethyl-6-t-butylphenol). Another
phenolic nonstaining antioxidant available commercially is
"Santowhite" powder as a 40 percent solution in water.
Esters of unsaturated fatty acids have also been found to be useful
to reduce the darkening of white and pastel-colored
neoprene-containing compositions. Principally, those oils of fatty
acids having one or two double bonds are preferred. Examples of
such oils include palm oil, predominantly palmittic acid,
triglyceride; olive oil, predominantly oleic acid triglyceride; and
safflower oil, predominantly linoleic acid triglyceride.
Combinations of these esters with the nondiscoloring phenolic
antioxidants have been found to be especially effective.
The incorporation of acid polymers into the compositions of this
invention also provides a product having improved strength, and
impregnated fabrics having improved crease retention and flat
stability. Acid polymers contemplated as being useful in this
present invention are prepared from any of the polymerizable acids,
i.e., those containing unsaturated groups. These polymers may be
homopolymers of the acids or interpolymers of the acids and other
monomers. Such acids include, for example, acrylic acid, maleic
acid, methylacrylic acid and polymerizable phosphoric acids.
Suitable monomers which may be copolymerized with the above acids
include esters of the above acids such as ethyl acrylate and methyl
methacrylate; alkyl fumarates and maleates; vinyl halides such as
vinyl chloride; and other vinyl monomers such as styrene,
acrylonitrile.
The acid polymers, as a general rule, are emulsion polymers
containing varying amounts of solids, normally in the range of
about 25 to 60 or 70 weight percent. Acrylic polymers of this type
are readily available commercially (under the trade name Rhoplex),
(under the trade name Hycar), (under the trade name Ucon).
The compositions of the invention may also contain polymeric
polyhydroxy compounds. These polyhydroxy compounds may be
water-soluble or insoluble. When incorporated into the compositions
of the invention, they result in the formation of a fabric with
improved flexibility and handle. By "polymeric polyhydroxy
compound" is meant a linear long-chain polymer having terminal
hydroxyl groups including branched, polyfunctional, polymeric
polyhydroxy compounds as set forth below. Among the suitable
polymeric polyhydroxy compounds there are included polyether
polyols such as polyalkylene ether glycols, polyalkylene-arylene
ether-thioether glycols and polyalkylene triols. Mixtures of these
polyols may be used when desired.
The polyalkylene ether glycols may be represented by the formula
HO(RO).sub.n H, wherein R is an alkylene radical which need not be
the same in each instance, and n is an integer. Examples of such
glycols include polyethylene ether glycol and polypropylene glycol.
Polyalkylene ether triols are obtained by reacting one or more
alkylene oxides with one or more low-molecular weight aliphatic
triols. The alkylene oxides most commonly used have molecular
weights between about 44 and 250 and these include for example,
ethylene oxide, propylene oxide, butylene oxide, and
1,2-epoxyoctane.
Representative examples of the polyalkylene ether triols include:
polypropylene ether triols (MW 700) made by reacting 608 parts of
1,2-propylene oxide with 92 parts of glycerine; polypropylene ether
triols (MW 1535) made by reacting 1,401 parts of 1,2-propylene
oxide with 134 parts of trimethylol propane; and polypropylene
ether triol (MW 6000) made by reacting 5,866 parts of 1,2-propylene
oxide with 134 parts of 1,2,6 -hexane triol.
Additional suitable polytriols include polyoxypropylene triols;
polyoxybutylene triols; Niax triols LG56,LG42, and LG112; Triol
TG-400; and Actol 32-160.
Thermosetting resins may also be included in the compositions of
this invention in amounts up to about 10 percent by weight.
Examples of thermosetting resins which are useful include phenolic
and aminoplast resins, such as the reaction products of phenol,
cresol, xylenol, urea, melamine and substituted melamines with
aldehydes such as formaldehyde, furfuraldehyde etc.
The term "phenolic resins" is used herein in its conventional
meaning and includes the resinous materials made from phenol and
aldehydes. These resins are also identified as phenoplasts. The
most widely used phenolic resin is phenolformaldehyde although
other suitable resins include phenol-furfural, p-tertiary-amyl
phenol-formaldehyde and cresylic acid-formaldehyde.
The commercially important aminoplast resins are the urea
formaldehyde and the melamine formaldehyde condensates. In general,
these resins are formed by condensing an amine with an aldehyde
such as by stirring one mole of urea with two moles of 37 percent
formalin at 25-30.degree. C. in alkaline solution until the
aldehyde is completely reacted. The conditions for reacting
melamine with aqueous formaldehyde are somewhat different from the
reactions of urea. Because of the low solubility of melamine in
water, the reactions are usually conducted at temperatures of
80.degree.- 100.degree. C. to bring the melamine into solution more
readily. The amino groups of melamine can each add two methylol
groups, while in urea, apparently only one mole of formaldehyde
adds to each amino group. Hexamethylol melamine is formed by
heating melamine at 90.degree. C. with an excess of
formaldehyde.
The alkyd resins are polyester resins obtained by reacting
polyhydric alcohols such as glycols, glycerol, sorbitol,
pentaerythritol etc., with polybasic acids such as phthalic acid,
maleic acid, adipic acid, azelaic acid and sebacic acid. These
resins may be modified with saturated and unsaturated monobasic
acids, saturated and unsaturated monohydricalalcohols, etc. The oil
modified alkyd resins are polyester resins which have been modified
with a drying and nondrying oil such as coconut oil, castor oil,
soybean oil, linseed oil, tung oil and the acids and glycerides
derived therefrom. Examples of such alkyd resins include coconut
oil-modified glyceryl phthalate containing about 33 percent by
weight of fatty acids, and soybean oil-modified glyceryl phthalate
resins containing about 41 percent by weight of fatty acids. The
alkyd resins are available commercially under a wide variety of
trade names from a variety of sources. Water-soluble alkyd resins
are available under the trade name AROTAP.
Typical aldehyde generating compounds which can be incorporated
into the compositions of the invention include linear polymers,
particularly those of the general formula HO(CH.sub.2 O).sub.n -H
which depolymerize to monomeric formaldehyde gas upon vaporization.
In this class of compounds, there are included lower
polyoxymethylene glycols, wherein n is from about 2 to 8;
paraformaldehyde, wherein n ranges from about 6 to 100;
alpha-polyoxy methylenes, wherein n is greater than about 100; and
beta-polyoxy methylene wherein n is greater than about 100.
Polyoxy methylene glycol derivatives may also be utilized. Examples
include the polyoxymethylene diacetates and the lower
polyoxymethylene dimethyl ethers. In general, higher temperatures,
e.g., up to about 200.degree. C. are utilized to effect
depolymerization of these derivatives. Formaldehyde acetate
(formals) may also be utilized. Preferred formals are produced by
reaction of formaldehyde with alcohols of the formula CHCH.sub.2
(OR).sub.2 in the presence of an acid catalyst, wherein R is alkyl
or aryl alkyl. These compounds hydrolize to formaldehyde and the
parent alcohol. Preferred formals include methylal and
1,3-dioxolane.
Other suitable aldehyde generating compounds include the various
methylol compounds, for example, methylol alkanolamine sulfites,
such as N-methylol-ethanolamine sulfite; methylol amides such as
N-methylol formamide, N-methylol acetamide and N-methylol
acrylamide; and amines such as trimethylolamine.
Also useful in the compositions of the invention are
water-insoluble silicone fluids such as SF-350, a dimethylsiloxane
polymer. Other commercially available dialkyl polysiloxanes are
useful.
The surfactants and wetting agents may be either nonionic or
anionic. Examples of nonionic wetting agents include alkyl aryl
polyether alcohols such as the ethylene oxide condensation products
of octylphenol available under the trade name TRITON X-100 and the
ethylene oxide condensation products of nonyl phenol available
under the trade name AEROSOL OT. Examples of anionic wetting agents
include metallic salts of disproportionated rosin acids and alkyl
esters of sulphosuccinic acids. Specific examples of the latter
wetting agents include the dihexyl ester of sodium sulphosuccinic
acid available under the trade name AEROSOL NA, and the diamyl
ester available under the trade name AEROSOL AY.
Although small amounts, for example, from about 0.1 to about 10
percent by weight of the surfactant wetting agent have been found
to be sufficient in the compositions of the invention, larger
amounts of the silicone fluids may be incorporated, for example,
from about 0-10 percent.
The following examples illustrate the compositions useful in this
invention.
Composition A Parts by Weight Neoprene 460 100 Bis phenol adduct of
methylene bis(4-phenylisocyanate), (40% in water) 50 Zinc oxide 7.5
Composition B Neoprene 460 50 Bis phenol adduct of Composition A
1.5 Zinc oxide dispersion (50% in water) 7 Syn-Fac 905 (a nonionic
wetting agent obtained by condensing 9.5 moles of ethylene oxide
with a mole of nonyl phenol) 1 Water 25 Composition C Neoprene 635
100 Lead tetroxide 7.5 Bis resorcinol adduct of hexamethylene
diisocyanate 15 Trichlorochloroethylene 100 Composition D Neoprene
Latex 635 (58% solids) 173 Zinc oxide dispersion (50% in water) 15
Neozone D; (N-phenyl-2-naphthylamine; 50% in water) 3 Nonic 218 (a
nonionic surfactant) 1 Composition E Neoprene Latex 750 (50%
solids) 200 Zinc oxide dispersion (50% in water) 15 Neozone D 3 Bis
phenol adduct of Composition A 50 Nonic 218 1 Composition F
Neoprene Latex 750 (50% solids) 200 Zinc oxide dispersion (50% in
water) 15 N-phenyl-2-naphthylamine (50% in water) 3 Bis phenol
adduct of Composition A 50 Rhoplex E-358 (a self-crosslinking
acrylic emulsion (25% in water) 1 Nonic 218 1 Composition G
Neoprene Latex 750 (50% solids) 200 Zinc oxide (50% in water) 15
Santowhite powder (a phenolic nonstaining antioxidant (40% in
water) 7.5 Bis phenol adduct of Composition A 50 Nonic 218 1.0
Composition H Neoprene Type W 75 Zinc oxide 5 Magnesium oxide 2
Methylene bis(4-phenyl isothiocyanate) 10 Toluene 100 Neozone A
(N-phenyl-1napthylamine; 50% in water) 3 Composition I Neoprene
Latex 750 (50% solids) 200 Zinc oxide (50% in water) 30 Santowhite
powder 7.5 Bis phenol adduct of Composition A 50 Nonic 218 1.0
Composition J Composition G, except that Latex 635 (50% solids) is
used in lieu of Latex 640 25 Hycar 2671 (an acrylic emulsion; 50%)
20 Polyethylene Glycol 600 (a polyethylene glycol having a
molecular weight of 600 3 Water 52 Composition K Composition G 25
Hycar 2671 20 Ucon 50MB 2000 (a polyethylene glycol prepared from a
mixture of ethylene and propylene glycols) 5 Syn-Fac 905 0.2 Water
49.2 Composition L Composition G (except that the Latex 750 is
replaced by Latex 635) 20 Rhoplex E-358 10 Water 70 Composition M
Composition G 15 Triol G 4000 (a water insoluble polypropylene
glycol having a molecular weight of about 6000) 5 Rhoplex E-358 10
Water 70 Composition N Composition G 10 Hycar 2671 15 Polyethylene
Glycol 600 5 Aerosol OT (surfactant) 0.2 Water 69.8 Composition O
Composition G 25 Hycar 2600 X 92 (ac acrylic emulsion containing
50% solids) 20 Ucon 2000 5 N-methylol-acetamide 10 Syntropol KB
(wetting agent) 1 Water 64 Composition P Same as Composition O
except that the acetamide is replaced by 10 parts of Rhonite R-1, a
dimethylol ethylene urea resin. Composition Q Composition G 25
Hycar 2671 20 Ucon 2000 5 Alkyd Resin M416 5 Melamine resin M387(a
melamine-formaldehyde resin as an 80% aqueous solution) 0.5 Water
44.5 Composition R Composition G 25 Hycar 2600 X 92 20 Alkyd resin
M416 5 Melamine resin M387 1 Silicone SF 96-500 (a dimethyl
polysiloxane fluid) 10 Water 39.5 Composition S Composition G 20
Hycar 2600 X 92 15 N-methylolacetamine 7 Alkyd Resin M416 5
Melamine Resin M387 1 Silicone SF350 5 Ucon 2000 10 Water 37
In preparing the compositions which are dispersions or emulsions,
it is often desirable to prepare dispersions of the separate
ingredients which can then be mixed in the customary manner. It has
been found, for example, that it is difficult to prepare a stable
emulsion or dispersion containing the components when the
components are indiscriminately added to water. On the other hand,
mixing of emulsions of the individual components is accomplished
readily. Thus, for example, it is preferred in preparing
dispersions such as composition G to prepare a zinc oxide
dispersion containing about 50 percent solids by stirring and
mixing in a ball mill, 100 parts of zinc oxide in 35 parts of
water, 30 parts of a 10 percent solution of Dexad 11, (a dispersing
agent), 35 parts of a 10 percent solution of ammonium caseinate (a
reacted casein), and 5 parts of a 10 percent solution of sodium
silicate. This mixture is milled for about 24 hours to form a
stable zinc oxide dispersion. The Santowhite powder (40 percent
solution) is likewise prepared in a ball mill by milling 100 parts
of the Santowhite powder in 80 parts of water, 30 parts of a 10
percent solution of Dexad 11, 30 parts of a 10 percent solution of
ammonium caseinate and 10 parts of a10 percent solution of sodium
silicate.
The bisphenol adduct dispersion (40 percent active ingredients) is
prepared by the same procedure by milling 100 parts of the adduct
with 80 parts of water, 30 parts of a 10 percent solution of the
Dexad 11, 30 parts of a 10 percent solution of ammonium caseinate
and 10 parts of a 5 percent solution of Aerosol OP, a wetting
agent.
After these separate emulsions are prepared, they are added to the
Neoprene Latex 750 and Nonic 218 surfactant and mixed in the
conventional manner.
In the preferred practice of this invention, the textile fabric is
impregnated with the compositions described above, either as
solutions, dispersions or emulsion. The amount of solids contained
in the solution, dispersion or emulsion preferably ranges from
about 8 to 12 parts of the neoprene elastomer, from about 1 to 5
parts of the isocyanate and from about 0.2 to 1 part of the metal
oxide, and the solids preferably should be diluted to provide a
liquid having a sufficiently low viscosity to permit the
composition to impregnate the fabric. Generally, the solution,
dispersion or emulsion applied to the fabric will contain from
about 40 to 50 percent by weight of solids.
The solutions, dispersions or emulsions are preferably padded on
the fabric. Conventional padding or spraying equipment can be used
for this purpose. Generally, a wet pickup of from about 60- 100
percent based on the weight of the fabric is obtained providing for
the incorporation of about 30- 50 percent of the chemical
solids.
After impregnation of the fabrics as described above, the fabrics
are dried and then either stored or processed further. At this
point, the impregnated fabrics have a propensity for subsequent
durable setting which can be effected by heat curing in the dry
state.
When the composition of the invention is prepared as an aqueous
emulsion or dispersion and the diisocyanate is blocked such as by
reaction with a phenol the fabric can be impregnated, dried and
stored for a longer period of time since curing cannot be effected
until the impregnated material is heated to a temperature
sufficient to dissociate the blocked isocyanate. In most instances,
the dissociation temperature is sufficiently high to provide a
presensitized fabric which is stable over a wide range of
temperatures. For example, the phenol adduct utilized in
Composition G dissociates at a temperature of about 320.degree. F.,
and therefore, the impregnated fabric must be heated at or above
this temperature to effect the cure and set the fabric.
It is this latter aspect of the invention that provides the most
desirable properties. The utilization of compositions such as
composition G permits the preparation of presensitized fabrics
which can be cut, converted to garments and thereafter cured while
being maintained in a preselected configuration to provide creases
and pleats as desired. These creases and pleats have been found to
possess improved wash and wear performance. That is, fabrics
treated in this manner exhibit improved crease and shape retention
and reduced shrinking when washed in a commercial washing machine.
Such improved properties are imparted by the present invention on
virtually all types of fabrics ranging from fabrics containing 100
percent natural fibers such as cotton or wool to fabrics composed
exclusively of synthetic fibers, such as polyesters and polyamides.
Fabrics containing blends of these fibers have also been found to
be improved by the compositions of the invention. The compositions
of the invention also have improved the performance of laminated
fabrics, such as for example fabrics composed of two or more layers
of fabrics or an outer layer of a fabric and an inner layer of a
foam such as a ureathane foam. Impregnation of such fabrics by the
compositions of the invention does not effect the bond between the
two layers, and can, therefore, be applied after lamination of the
fabrics.
The following table illustrates the results obtained when a variety
of fabrics is treated in accordance with the process of the
invention. All the fabrics listed in the table, except fabric 4
were impregnated with the identified solutions to a wet pickup of
80 percent based on the weight of the fabric, dried, pressed on a
Hoffman press utilizing a cycle of 40 seconds steam, 5 seconds bake
and 5 seconds vacuum, and thereafter cured by heating to a
temperature of 300.degree. F. for a period of 20 minutes. The
treatment of fabric 4 differs in that the wet pickup of composition
K was 70 percent. The crease retention and flat dry results are
based on a scale of from 1 to 5, 1 representing no crease retention
and 5 representing an excellent crease. As can be seen from the
data contained in the table, fabrics impregnated with the
compositions of the invention exhibit excellent crease retention
and flat dry properties and improve resistance to shrinkage.
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