U.S. patent application number 09/821313 was filed with the patent office on 2002-03-14 for methods for improving water absorbency of fabrics and fabrics with improved properties.
This patent application is currently assigned to The Procter & Gamble Company. Invention is credited to Arredondo, Victor Manuel, Mellea, Michelle Frances, Payet, George L..
Application Number | 20020031970 09/821313 |
Document ID | / |
Family ID | 22711495 |
Filed Date | 2002-03-14 |
United States Patent
Application |
20020031970 |
Kind Code |
A1 |
Arredondo, Victor Manuel ;
et al. |
March 14, 2002 |
Methods for improving water absorbency of fabrics and fabrics with
improved properties
Abstract
Methods for providing fabric with good water absorbency and
durable press properties comprise treating the fabric with a
treatment composition comprising formaldehyde, catalyst for
crosslinking the formaldehyde with natural fibers in the fabric,
and silicone elastomer or a precursor thereof, and heating the
treated fabric to effect crosslinking of the formaldehyde. Methods
for providing fabric with good water absorbency and shrinkage
resistance properties comprise treating the fabric with a treatment
composition comprising formaldehyde, catalyst for crosslinking the
formaldehyde with natural fibers in the fabric, and silicone
elastomer or a precursor thereof, and heating the treated fabric to
effect crosslinking of the formaldehyde. Fabrics having good water
absorbency in combination with additional advantageous properties
are produced.
Inventors: |
Arredondo, Victor Manuel;
(West Chester, OH) ; Mellea, Michelle Frances;
(Hamilton, OH) ; Payet, George L.; (Cincinnati,
OH) |
Correspondence
Address: |
THE PROCTER & GAMBLE COMPANY
PATENT DIVISION
IVORYDALE TECHNICAL CENTER - BOX 474
5299 SPRING GROVE AVENUE
CINCINNATI
OH
45217
US
|
Assignee: |
The Procter & Gamble
Company
|
Family ID: |
22711495 |
Appl. No.: |
09/821313 |
Filed: |
March 29, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60192903 |
Mar 29, 2000 |
|
|
|
Current U.S.
Class: |
442/414 ;
442/327; 442/333 |
Current CPC
Class: |
Y10T 442/696 20150401;
D06M 15/693 20130101; D06M 2101/12 20130101; Y10T 442/607 20150401;
D06M 2200/45 20130101; D06M 13/127 20130101; D06M 2101/06 20130101;
D06M 2200/20 20130101; D06M 2200/00 20130101; Y10T 442/60 20150401;
D06M 15/643 20130101 |
Class at
Publication: |
442/414 ;
442/327; 442/333 |
International
Class: |
D04H 001/00; D04H
003/00; D04H 013/00 |
Claims
What is claimed is:
1. A method for providing fabric with good water absorbency and
durable press properties, comprising treating the fabric with a
treatment composition comprising formaldehyde, catalyst for
crosslinking the formaldehyde with natural fibers in the fabric,
and silicone elastomer or a precursor thereof, and heating the
treated fabric to effect crosslinking of the formaldehyde.
2. A method according to claim 1, wherein the fabric comprises at
least about 20% by weight of cotton fibers.
3. A method according to claim 1, wherein the treatment composition
consists essentially of formaldehyde, catalyst and silicone
elastomer or a precursor thereof.
4. A method according to claim 1, wherein the treatment composition
is free of aminoplast resin.
5. A method according to claim 1, wherein the treatment composition
comprises a silicone elastomer precursor.
6. A method according to claim 1, wherein the treated fabric
exhibits a water absorbency time of less than about 100 seconds as
measured according to AATCC Method 79-1995 after the fabric has
been aqueous laundered at least one time, a durable press value of
at least about 3 after the fabric has been aqueous laundered at
least one time, and/or a length shrinkage and a width shrinkage of
less than about 5% each after the fabric has been aqueous laundered
one time.
7. A method for providing fabric with good water absorbency and
shrinkage resistance properties, comprising treating the fabric
with a treatment composition comprising formaldehyde, catalyst for
crosslinking the formaldehyde with natural fibers in the fabric,
and silicone elastomer or a precursor thereof, and heating the
treated fabric to effect crosslinking of the formaldehyde.
8. A method according to claim 7, wherein the fabric comprises at
least about 20% by weight of rayon fibers.
9. A method according to claim 7, wherein the treatment composition
consists essentially of formaldehyde, catalyst and silicone
elastomer or a precursor thereof.
10. A method according to claim 7, wherein the treatment
composition is free of aminoplast resin.
11. A method according to claim 7, wherein the treatment
composition comprises a silicone elastomer precursor.
12. A method according to claim 7, wherein the treated fabric
exhibits a water absorbency time of less than about 100 seconds as
measured according to AATCC Method 79-1995 after the fabric has
been aqueous laundered at least one time.
13. A method according to claim 12, wherein the treated fabric
exhibits a length shrinkage and a width shrinkage of less than
about 5% each after the fabric has been aqueous laundered at least
one time, and/or a durable press value of at least about 3 after
the fabric has been aqueous laundered at least one time.
14. A method of providing rayon fabric with reduced shrinkage and
good water absorbency, comprising crosslinking cellulose in the
fabric with formaldehyde and providing the fabric with a silicone
elastomer.
15. A method according to claim 14, wherein the fabric comprises at
least about 50% by weight of rayon fibers.
16. A method according to claim 14, wherein the treated fabric
exhibits a water absorbency time of less than about 100 seconds as
measured according to AATCC Method 79-1995 after the fabric has
been aqueous laundered at least one time.
17. A method according to claim 16, wherein the treated fabric
exhibits a length shrinkage and a width shrinkage of less than
about 5% each after the fabric has been aqueous laundered at least
one time.
18. A method according to claim 17, wherein the treated fabric
exhibits a durable press value of at least about 3 after the fabric
has been aqueous laundered at least one time.
19. Fabric comprising rayon fibers and exhibiting a water
absorbency time of less than about 100 seconds as measured
according to AATCC Method 79-1995 after the fabric has been aqueous
laundered at least one time.
20. Fabric according to claim 19, wherein the treated fabric
exhibits a length shrinkage and a width shrinkage of less than
about 5% each after the fabric has been aqueous laundered at least
one time.
21. Fabric according to claim 20, wherein the treated fabric
exhibits a durable press value of at least about 3 after the fabric
has been aqueous laundered at least one time.
22. Fabric comprising cotton fibers, having a crosslinked
formaldehyde durable press treatment, provided with a silicone
elastomer, and exhibiting a water absorbency time of less than
about 100 seconds as measured according to AATCC Method 79-1995
after the fabric has been aqueous laundered at least one time,
wherein the fabric does not comprise 100% cotton.
23. A method for providing fabric with good water absorbency and at
least one of durable press properties and shrinkage resistance,
comprising treating the fabric with a treatment composition
comprising formaldehyde and catalyst for crosslinking the
formaldehyde with natural fibers in the fabric, treating the fabric
with silicone elastomer or a precursor thereof, and heating the
treated fabric to effect crosslinking of the formaldehyde.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 37 U.S.C. .sctn.
119(e) to U.S. Provisional Application Ser. No. 60/192,903, filed
Mar. 29, 2000 (Attorney Docket No.8008P).
FIELD OF THE INVENTION
[0002] This invention relates to methods for providing fabrics,
particularly fabrics containing natural fibers such as cotton,
rayon and the like, with good water absorbency in combination with
durable press and/or shrinkage resistance. This invention also
relates to cellulose fabrics which have improved water absorbency,
particularly in combination with good durable press properties
and/or shrinkage resistance.
BACKGROUND OF THE INVENTION
[0003] Many fabrics, particularly fabrics comprising natural
fibers, do not possess durable press (or "wash and wear" or
"smooth-dry") performance or dimensional stability, i.e., shrinkage
resistance. Cellulosic fabrics such as cotton have been treated
with aminoplast resins, including N-methylol cross-linking resins
such as dimethylol dihydroxyethyleneurea (DMDHEU) or dimethylol
propylcarbamate (DMPC), to impart durable press properties, as
disclosed, for example, in the Martin et al U.S. Pat. No.
4,521,176. Unfortunately, many reacted aminoplast resins break down
during storage, thus releasing formaldehyde. The formaldehyde
release may occur not only throughout the preparation of the fabric
but also during garment-making. Further, garments or fabrics
treated with aminoplast resins may release additional formaldehyde
when stored under humid conditions. Aminoplast resins may also
hydrolyze during washing procedures, resulting in a loss of the
durable press performance. Additionally, aminoplast resins tend to
give fabric a harsher handle, that is, make the fabric feel less
soft. As the resins make the fabric feel less soft, the fabric must
be treated with additional softeners, for example silicone
softeners. Unfortunately, the silicone softeners tend to make the
fabric hydrophobic although it is often preferred that the fabric
have hydrophilic properties.
[0004] Cellulosic fibers have also been cross-linked with
formaldehyde to impart durable press properties. For example, the
Payet U.S. Pat. Nos. 3,960,482, 3,960,483, 4,067,688 and 4,104,022
disclose durable press processes which comprise impregnating a
cellulosic fiber-containing fabric with an aqueous solution
comprising a catalyst, and, while the fabric has a moisture content
of above 20% by weight, exposing the fabric to formaldehyde vapors
and curing under conditions at which formaldehyde reacts with the
cellulose. The Payet U.S. Pat. No. 4,108,598 discloses a process
which comprises treating cellulosic fiber-containing fabrics with
an aqueous solution of formaldehyde and a catalyst, heat curing the
treated fabric by introducing the fabric into a heating zone, and
gradually increasing the temperature of the heating zone, thereby
increasing the temperature of the heated fabric to prevent the loss
of an amount of formaldehyde which will reduce the overall extent
of curing. The Payet U.S. Pat. No. 5,885,303 also discloses a
durable press process for cellulosic fiber-containing fabrics. The
process comprises treating the fabric with an aqueous solution of
formaldehyde, a catalyst capable of catalyzing the cross-linking
reaction between formaldehyde and cellulose, and an effective
amount of a silicone elastomer to reduce loss in tear strength in
the treated fabric. Formaldehyde is generally less expensive than
aminoplast resins, and formaldehyde treatment of cellulosic fabrics
typically results in durable press properties which are more
durable than those obtained by aminoplast resins.
[0005] Rayon garments are desirable by consumers for a variety of
reasons. However, many durable press treatment processes that have
been provided for cotton cellulosic fabrics have not been suitable
for rayon fabrics. Although rayon and cotton are both cellulosic
fibers, they react very differently from one another. Particularly,
rayon-containing fabrics exhibit significant shrinkage when
subjected to aqueous washing or laundering and therefore generally
require dry cleaning as opposed to washing in an aqueous
environment.
[0006] The copending Payet application Ser. No. 09/163,319
discloses processes for providing rayon fabrics with durable press
properties wherein a rayon fiber-containing fabric is treated with
an aqueous mixture containing a high concentration of formaldehyde
and a catalyst capable of catalyzing the cross-linking reaction
between formaldehyde and the rayon, and the treated fabric is heat
cured. Payet discloses that the fabric may be washed or laundered
in an aqueous system and does not shrink substantially on aqueous
washing. Additionally, a silicone elastomer may be employed to
reduce loss in tear and tensile strength in the treated fabric.
[0007] An important feature of cellulose fabrics, both cotton and
rayon particularly, is that they are naturally hydrophilic, and
therefore absorb moisture. Typically, garments made of fabrics
which are hydrophilic are more comfortable for wear and therefore
are preferred by consumers over garments which are formed of
hydrophobic, non-moisture absorbing fabrics. However, many
conventional fabric treatments for improving durable press and/or
for reducing shrinkage of cellulose fabrics, and particularly for
cotton and rayon fabrics, inhibit the natural water absorbency of
the cellulose fibers and render the fabrics hydrophobic. Such
fabrics are therefore not preferred for garment use owing to their
reduced ability or substantial inability to absorb moisture.
[0008] Accordingly, there is a continuing need to further improve
individual characteristics of fabrics containing natural fibers,
for example cotton and rayon, and to improve the overall
combinations of properties exhibited by such fabrics.
SUMMARY OF THE INVENTION
[0009] Accordingly, it is an object of the present invention to
obviate problems of the prior art. It is a further object of the
present invention to provide methods for improving the water
absorbency of fabrics and particularly to improve the water
absorbency of treated fabrics containing natural fibers, i.e.,
fabrics which are treated to provide additional advantageous
properties, for example durable press properties and/or shrinkage
resistance. It is a related object to provide methods for preparing
fabrics which exhibit advantageous combinations of properties and
which are suitable for aqueous washing or laundering, and to
provide cellulose fabrics which exhibit advantageous combinations
of properties and which are suitable for aqueous washing or
laundering.
[0010] These and additional objects are provided by the methods and
fabrics of the invention. In one embodiment, the invention is
directed to methods for providing fabric with good water absorbency
and durable press properties, which methods comprise treating the
fabric with a treatment composition comprising formaldehyde,
catalyst for crosslinking the formaldehyde with natural fibers in
the fabric, and silicone elastomer or a precursor thereof, and
heating the treated fabric to effect crosslinking of the
formaldehyde. In another embodiment, the invention is directed to
methods for providing fabric with good water absorbency and
shrinkage resistance properties, which methods comprising treating
the fabric with a treatment composition comprising formaldehyde,
catalyst for crosslinking the formaldehyde with natural fibers in
the fabric, and silicone elastomer or a precursor thereof, and
heating the treated fabric to effect crosslinking of the
formaldehyde. In a further embodiment, the invention is directed to
methods for providing rayon fabric with reduced shrinkage and good
water absorbency, which methods comprise crosslinking cellulose in
the fabric with formaldehyde and providing the fabric with a
silicone elastomer. In yet additional embodiments, the invention is
directed to fabric comprising rayon fibers and exhibiting a water
absorbency time of less than about 100 seconds as measured
according to AATCC Method 79-1995 after the fabric has been aqueous
laundered at least one time, and to fabric comprising cotton fibers
and having a crosslinked formaldehyde durable press treatment and
exhibiting a water absorbency time of less than about 100 seconds
as measured according to AATCC Method 79-1995 after the fabric has
been aqueous laundered at least one time, wherein the fabric does
not comprise 100% cotton.
[0011] The methods of the invention are advantageous in providing
fabrics which exhibit good water absorbency, particularly in
combination with other desirable properties, for example durable
press properties and/or shrinkage reduction.
[0012] These and additional aspects, objects and advantages of the
invention are more fully described in the detailed description.
DETAILED DESCRIPTION
[0013] The present invention is directed to methods for providing
fabrics, particularly fabrics comprising natural fibers, with good
water absorbency in combination with good durable press properties
and/or shrinkage resistance. This invention also relates to fabrics
which have good water absorbency, particularly in combination with
durable press and/or shrinkage resistance and which can be
subjected to aqueous laundering.
[0014] As is known in the art, the water absorbency of a fabric
indicates the ability of the fabric to absorb moisture,
particularly surface moisture. As employed in the present
invention, good water absorbency indicates that the fabric absorbs
a drop of water placed thereon, in accord with the methods
described in AATCC Method 79-1995, in less than about 100
seconds.
[0015] The fabrics employed in the present invention preferably
comprise natural fibers. As used herein, "individual fiber" refers
to a short and/or thin filament, such as short filaments of cotton
as obtained from the cotton boll, short filaments of wool as
sheared from the sheep, filaments of cellulose or rayon, or the
thin filaments of silk obtained from a silkworm cocoon. As used
herein, "fibers" is intended to include filaments in any form,
including individual filaments, and the filaments present in formed
yarns, fabrics and garments.
[0016] As used herein, "yarn" refers to a product obtained when
fibers are aligned. Yarns are products of substantial length and
relatively small cross-section. Yarns may be single ply yarns, that
is having one yam strand, or multiple ply yarns, such as 2-ply yarn
which comprises two single yarns twisted together or 3-ply yarn
which comprises three yarn strands twisted together. As used
herein, "fabrics" generally refer to knitted fabrics, woven
fabrics, or non-woven fabrics prepared from yarns or individual
fibers, while "garments" generally refer to wearable articles
comprising fabrics, including, but not limited to, shirts, blouses,
dresses, pants, sweaters and coats. Non-woven fabrics include
fabrics such as felt and are composed of a web or batt of fibers
bonded by the application of heat and/or pressure and/or
entanglement. "Textiles" includes fabrics, yams, and articles
comprising fabrics and/or yarns, such as garments, home goods,
including, but not limited to, bed and table linens, draperies and
curtains, and upholsteries, and the like.
[0017] As used herein, "natural fibers" refer to fibers which are
obtained from natural sources, such as cellulosic fibers and
protein fibers, or which are formed by the regeneration of or
processing of natural occurring fibers and/or products. Natural
fibers are not intended to include fibers formed from petroleum
products. Natural fibers include fibers formed from cellulose, such
as cotton fiber and regenerated cellulose fiber, commonly referred
to as rayon, or acetate fiber derived by reacting cellulose with
acetic acid and acetic anhydride in the presence of sulfuric acid.
As used herein, "natural fibers" are intended to include natural
fibers in any form, including individual filaments, and fibers
present in yarns, fabrics and other textiles, while "individual
natural fibers" is intended to refer to individual natural
filaments.
[0018] As used herein, "cellulosic fibers" are intended to refer to
fibers comprising cellulose, and include, but are not limited to,
cotton, linen, flax, rayon, cellulose acetate, cellulose
triacetate, hemp and ramie fibers. As used herein, "rayon fibers"
is intended to include, but is not limited to, fibers comprising
viscose rayon, high wet modulus rayon, cuprammonium rayon,
saponified rayon, modal rayon and lyocell rayon. "Protein fibers"
are intended to refer to fibers comprising proteins, and include,
but are not limited to, wools, such as sheep wool, alpaca, vicuna,
mohair, cashmere, guanaco, camel and llama, as well as furs,
suedes, and silks.
[0019] As used herein, "synthetic fibers" refer to those fibers
which are not prepared from naturally occurring filaments and
include, but are not limited to, fibers formed of synthetic
materials such as polyesters, polyamides such as nylons,
polyacrylics, and polyurethanes such as spandex. Synthetic fibers
include fibers formed from petroleum products.
[0020] Fabrics for use in the present invention preferably comprise
natural fibers, which natural fibers may be included in any form,
including, but not limited to, in the form of individual fibers
(for example in nonwoven fabrics), or in the form of yarns
comprising natural fibers, woven or knitted to provide the fabrics.
Additionally, the fabrics may be in the form of garments or other
textiles comprising natural fibers. The fabrics may further
comprise synthetic fibers. Preferably, the fabrics comprise at
least about 20% natural fibers. In one embodiment, the fabrics
comprise at least about 50% natural fibers such as cotton fibers,
rayon fibers or the like. In another embodiment, the fabrics
comprise at least about 80% natural fibers such as cotton fibers,
rayon fibers or the like, and in a further embodiment, the fibers
comprise 100% natural fibers. Fabrics comprising cellulose fibers
such as cotton and/or rayon are preferred for use in the present
invention.
[0021] While not being bound by theory, it is believed that when
natural fibers are treated with a composition comprising
formaldehyde and a catalyst capable of cross-linking formaldehyde
with a natural fiber, a chemical modification of the natural fibers
occurs. It is believed that the formaldehyde reacts chemically with
the natural fibers to cross-link the individual polymer chains of
the natural fibers, and establish the durable press properties
and/or dimensional stability, i.e., reduced shrinkage. In
accordance with the present methods, a silicone elastomer or
precursor thereof is included in the formaldehyde treatment and the
fabrics exhibit good water absorbency. The fabrics preferably also
exhibit good strength, for example good tear strength.
[0022] To provide the crosslinked formaldehyde treatment, the
fabric is typically treated with a treatment composition comprising
formaldehyde, a catalyst and a silicone elastomer or precursor
thereof, followed by drying and/or curing of the treated fabric.
Formaldehyde is generally available in an aqueous solution,
referred to as formalin, comprising water, about 37% by weight
formaldehyde, and generally about 10% to 15% by weight
methanol.
[0023] The amount of formaldehyde in the treatment composition is
preferably sufficient to impart a durable press property and/or
shrinkage resistance to the fabric. Generally the fabric is treated
with at least about 3% by weight formalin, and preferably with from
about 3% to about 35% by weight formalin, based on the weight of
the fabric. In one embodiment, for example wherein the fabric
comprises cotton fibers, the fabric is treated with about 3% to
about 8% formalin, based on the weight of the fabric. In another
embodiment, for example wherein the fabric comprises rayon fibers,
the fabric is treated with from about 10% to about 20% by weight
formalin, based on the weight of the fabric. In yet another
embodiment, for example wherein the fabric comprises a 50/50
rayon/polyester blend, the fabric is treated with from about 5% to
about 10%, more specifically about 8%, by weight formalin, based on
the weight of the fabric. As used herein, "formalin" refers to an
aqueous solution comprising 37%, by weight, formaldehyde. As will
be apparent to one of skill in the art, formaldehyde solutions
comprising levels of formaldehyde other than 37%, by weight, may
also be used. Using the above ranges of formalin, the fabric is
treated with actual formaldehyde, as opposed to formalin, at a
level of from about 1% to about 13%, preferably from about 1% to
about 12%, based on the weight of the fabric. Thus, in one
embodiment, for example wherein the fabric comprises cotton fibers,
the fabric is treated with about 1% to about 3% formaldehyde, as
opposed to formalin, based on the weight of the fabric. In another
embodiment, for example wherein the fabric comprises rayon fibers,
the fabric is treated with from about 4% to about 8% by weight
formaldehyde, as opposed to formalin, based on the weight of the
fabric. In yet another embodiment, wherein the fabric comprises a
50/50 rayon/polyester blend, the fabric is treated with about 2% to
about 4% by weight formaldehyde, as opposed to formalin, based on
the weight of the fabric.
[0024] Suitable catalysts are those capable of catalyzing a
cross-linking reaction between formaldehyde and a natural fiber,
and preferably are catalysts capable of catalyzing the
cross-linking of formaldehyde with a natural fiber comprising
hydroxy groups, such as cellulosic fibers. Catalysts which may be
used include mineral acids, organic acids, salts of strong acids,
ammonium salts, alkylamine salts, metallic salts and combinations
thereof. In one embodiment the catalyst is other than a mineral
acid.
[0025] Suitable mineral acid catalysts include hydrochloric acid,
sulfuric acid, nitric acid, phosphoric acid and boric acid.
Suitable organic acids include oxalic acid, tartaric acid, citric
acid, malic acid, glycolic acid, methoxyacetic acid, chloroacetic
acid, lactic acid, 3-hydroxybutyric acid, methane sulfonic acid,
ethane sulfonic acid, hydroxymethane sulfonic acid, benzene
sulfonic acid, p-toluene sulfonic acid, cyclopentane
tetracarboxylic acid, butane tetracarboxylic acid,
tetrahydrofuran-tetracarboxylic acid, nitrilotriacetic acid, and
ethylenediaminetetraacetic acid. Suitable salts of strong acids
include sodium bisulfate, sodium dihydrogen phosphate and disodium
hydrogen phosphate. Suitable ammonium salts include ammonium
chloride, ammonium nitrate, ammonium sulfate, ammonium bisulfate,
ammonium dihydrogen phosphate and diammonium hydrogen phosphate.
Suitable alkanolamine salts include the hydrochloride, nitrate,
sulfate, phosphate and sulfamate salts of 2-amino-2-methyl-
1-propanol, tris (hydroxymethyl) aminomethane and
2-amino-2-ethyl-1-3-propanediol. Suitable metal salts include
aluminum chlorohydroxide, aluminum chloride, aluminum nitrate,
aluminum sulfate, magnesium chloride, magnesium nitrate, magnesium
sulfate, zinc chloride, zinc nitrate and zinc sulfate, and mixtures
thereof.
[0026] In one embodiment of the invention, the catalyst is a halide
or nitrate salt of zinc or magnesium, and preferably the catalyst
is magnesium chloride. An organic acid, such as citric acid, may be
used in combination with the halide or nitrate salt of zinc or
magnesium. Generally the molar ratio of metal salt to organic acid
is from about 5:1 to about 20:1. In one embodiment, the catalyst
comprises magnesium chloride and citric acid, while in another
embodiment the catalyst comprises magnesium chloride and aluminum
chloride.
[0027] The fabric is typically treated with an amount of catalyst
sufficient to catalyze cross-linking of the natural fibers by the
formaldehyde to provide good water absorbency, and at least one of
good durable press properties and/or reduced shrinkage, for example
reduced shrinkage upon aqueous laundering. In one embodiment, the
catalyst may be employed in an amount sufficient to provide a
formaldehyde:catalyst weight ratio of from about 10:1 to about
1:10, and preferably from about 5:1 to about 1:5.
[0028] The formaldehyde treatment composition may comprise, by
weight, up to about 12% of a catalyst solution, and preferably from
about 1% to about 9% of a catalyst solution. Generally the catalyst
solution comprises from about 20% to about 50%, by weight catalyst.
In one embodiment, for example wherein the fabric comprises cotton
fibers, the treatment solution comprises from about 2 to about 4%
by weight of a catalyst solution comprising about 30% by weight
catalyst, and in another embodiment, for example wherein the fabric
comprises rayon fibers, the treatment solution comprises from about
6% to about 8% by weight of a catalyst solution comprising about
30% by weight catalyst. In yet a further embodiment, the catalyst
solution comprises about 40%, by weight, magnesium chloride, for a
final magnesium chloride level of up to about 5%, by weight of the
treatment solution. Suitable catalyst solutions include
FREECAT.RTM. LF (magnesium chloride and citric acid) and
FREECAT.RTM. No. 9 (aluminum chloride and magnesium chloride),
commercially available from B. F. Goodrich.
[0029] The formaldehyde treatment composition typically comprises a
liquid carrier, preferably water, although, as noted above, the
formalin used to prepare the treatment composition may comprise
small amounts of organic solvents such as methanol or the like. In
one embodiment, the treatment composition is free of any organic
solvents other than that present in the formalin or the catalyst
solution. In another embodiment, the carrier may comprise
pentamethylcyclosiloxane.
[0030] According to the present methods, a silicone elastomer or
precursor thereof is included in the formaldehyde-containing
treatment composition with which the fabric is treated. Thus, the
formaldehyde treatment composition comprises formaldehyde, catalyst
and silicone elastomer or a precursor thereof. It has been
discovered that the combination of a silicone elastomer or
precursor thereof and the formaldehyde-containing treatment
composition provides the fabric with good water absorbency, while
also providing good durable press and/or shrinkage resistance
properties. This is remarkable in that many conventional durable
press and/or shrinkage resistance treatments render the treated
fabrics hydrophobic. The silicone elastomer may also be effective
to reduce the loss in tear and tensile strength that typically
occurs during formaldehyde cross-linking of fibers.
[0031] Various silicone elastomers are known in the art and are
suitable for use in the methods and fabrics of the invention. In
one embodiment, the silicone elastomer is a polysiloxane.
Similarly, the silicone elastomer precursor which forms an
elastomer upon curing, typically by self curing, may be a
polysiloxane. Elastomers are polymers which are capable of being
stretched with relatively little applied force, and which return to
the unstretched length when the force is released. Silicone
elastomers have a backbone made of silicon and oxygen with organic
substituents attached to silicon atoms, with a number n of
repeating units of the general formula: 1
[0032] The groups R and R are each independently selected from
lower alkyls, preferably C.sub.1-C.sub.3 alkyls, phenyl, or lower
alkyls or phenyls comprising a group reactive to cellulose, such as
hydroxy groups, halogen atoms, for example, fluoride, or amino
groups. Suitable elastomers include those disclosed in U.S. Pat.
No. 5,885,303, incorporated herein by reference.
[0033] A preferred silicone elastomer or precursor composition
comprises up to about 60%, by weight, silicone solids. In one
embodiment, the silicone elastomer or precursor composition
comprises from about 20% to about 60%, preferably from about 30% to
about 60%, by weight of silicone solids, while in another
embodiment the silicone elastomer or precursor composition
comprises from about 20% to about 30% by weight of silicone solids.
Suitable silicone elastomer precursors include a dimethyl silicone
emulsion containing from about 30% to about 60%, by weight,
silicone solids, commercially available as SM2112 from General
Electric. Another suitable commercially available elastomer
precursor is Sedgesoft ELS from Sedgefield Specialties, containing
from about 24% to about 26%, by weight, silicone solids.
[0034] When the silicone elastomer or precursor thereof is applied
to the fabric with a liquid formaldehyde treatment composition, the
liquid treatment composition may comprise up to about 10%,
preferably from about 1% to about 5%, more preferably from about 1%
to about 3%, by weight of the elastomer or precursor solids. In one
embodiment, the treatment composition comprises from about 1% to
about 3%, preferably from about 1.5% to 3%, by weight silicone
solids, while in another embodiment, the composition comprises from
about 1% to about 1.5% by weight silicone solids.
[0035] The formaldehyde treatment composition may be applied to the
fabric in accordance with any of the conventional techniques known
in the art. In one embodiment, the treatment composition may be
applied to the fabric by saturating the fabric in a trough and
squeezing the saturated fabric through pressure rollers to achieve
a uniform application (padding process). As used herein "wet
pick-up" refers to the amount of treatment composition applied to
and/or absorbed into the fabric based on the original weight of the
fabric. "Original weight of the fabric" or simply "weight of the
fabric" refers to the weight of the fabric prior to its contact
with the treatment composition. For example, 50% pick-up means that
the fabric picks up an amount of treatment solution equal to 50% of
the fabric's original weight. Preferably the wet pick-up is at
least 20%, preferably from about 50% to 100%, more preferably from
about 65% to about 80%, by weight of the fabric.
[0036] Other application techniques which may be employed include
kiss roll application, engraved roll application, printing, foam
finishing, vacuum extraction, spray application or any process
known in the art. Generally theses techniques provide lower wet
pick-up than the padding process. The concentration of the
chemicals in the solution may be adjusted to provide the desired
amount of chemicals on the original weight of the fabric (OWF).
[0037] In a preferred embodiment, the formaldehyde treatment
composition is applied in an amount to insure a moisture content of
more than 20% by weight, preferably more than 30% by weight, on the
fabric before curing. Optionally, a wetting agent may be included
in the treatment composition to facilitate obtaining the desired
moisture content. Nonionic wetting agents are preferred.
[0038] Once the treatment composition has been applied to the
fabric, the fabric is typically heated for a time and at a
temperature sufficient for the cross-linking of the natural fibers
with the formaldehyde. For example, the fabric may be heated at a
temperature greater than about 250F, preferably from about 250F to
about 350F, in an oven for a period of from about 15 seconds to
about 15 minutes, preferably from about 45 seconds to about 3
minutes, to react the formaldehyde with the natural fibers in the
fabric and affect crosslinking of the formaldehyde and natural
fibers to provide durable press and/or shrinkage resistance
effects. There is an inverse relationship between curing
temperature and curing time, that is, the higher the temperature of
curing, the shorter the dwell time in the oven; conversely, the
lower the curing temperature, the longer the dwell time in the
oven.
[0039] In another embodiment, the present invention comprises
methods for improving the water absorbency of fabric, wherein the
silicone elastomer may be included in the treated fabric by means
of a separate treatment step before or after the formaldehyde
crosslinking treatment. Additionally, if the silicone elastomer or
precursor thereof is applied to the fabric subsequent to treatment
with the formaldehyde crosslinking composition, the silicone
elastomer precursor thereof may be applied prior to or subsequent
to the heating step which is employed to affect curing of the
formaldehyde with the natural fibers of the fabric, although
application prior to heating is preferred. The applied silicone
elastomer or precursor thereof may be dried, with self curing of
the precursor being affected thereby.
[0040] The fabrics according to the present invention exhibit good
water absorbency. As noted above this indicates that the fabrics
exhibit a water absorbency time, in accord with the methods
described in AATCC Method 79-1995, of less than about 100 seconds.
In a more specific embodiment, the fabrics according to the present
invention exhibit a water absorbency time, in accord with the
methods described in AATCC Method 79-1995, of less than about 80
seconds, even after the fabric has been aqueous laundered at least
once. In yet a further embodiment, the fabrics according to the
present invention exhibit a water absorbency time, in accord with
the methods described in AATCC Method 79-1995, of less than about
60 seconds, even after the fabric has been aqueous laundered at
least once. One skilled in the art will appreciate that various
fabric preparation processes may involve application of a wetting
agent to the fabric. Typically, wetting agents may be employed to
improve wet pick-up of chemistry during fabric finishing. The water
absorbency properties as disclosed herein are exhibited by the
fabric after any such wetting agent has been removed, for example
by laundering or the like. Thus, the good water absorbency
properties are maintained after one or more washings or launderings
of the fabrics. The good water absorbency properties are
particularly advantageous when the fabric is used in garment
manufacture, as garments which absorb moisture are generally more
comfortable for wear and therefore are preferred by consumers over
garments which are formed of hydrophobic, non-moisture absorbing
fabrics.
[0041] The fabrics according to the invention also exhibit good
durable press properties and/or good shrink resistance. In one
embodiment, it is preferred that the fabric exhibit good durable
press, for example a DP (durable press) rating of at least about
3.0, preferably at least about 3.25, and more preferably at least
about 3.5, as measured according to AATCC Test Method 124-1996,
after one aqueous washing, more preferably after five aqueous
washings, and/or good shrinkage resistance, for example a length
shrinkage and a width shrinkage of less than about 10% each,
preferably less than about 5% each, more preferably less than about
4% each, and even more preferably less than about 2% each, and in
certain embodiments, less than about 1% each, as measured according
to AATCC Test Method 135-1995, after one machine washing, more
preferably after five aqueous washings. Shrinkage resistance may
also be measured according to AATCC Test Method 150-1995. In
further preferred embodiments, the fabrics exhibit good filling
tensile and tear strengths, for example of at least about 25 pounds
and at least about 24 ounces, respectively, as measured according
to ASTM D- 5035-95 for tensile strength, and ASTM D-2261-96 for
tear strength.
[0042] In another embodiment, cellulose fabrics having a
crosslinked formaldehyde treatment and exhibiting good water
absorbency, even after laundering, are obtained, provided that the
fabric does not comprise 100% cotton. These fabrics may comprise
greater than about 20% cotton fibers, greater than about 50% cotton
fibers, greater than about 80% cotton fibers, greater than about
20% rayon fibers, greater than about 50% rayon fibers, greater than
about 80% rayon fibers, or about 100% rayon fibers.
[0043] In a further embodiment, the fabrics according to the
invention exhibit good hand or softness, in the absence of
conventional softeners such as silicone or polyethylene softeners.
Typically, the fabrics will exhibit a low coefficient of friction
and/or a high flexibility/Instron softness.
[0044] In processes in accordance with the present invention,
unreacted formaldehyde remaining on the fabric is removed during
subsequent processing of the fabric. Generally, the final substrate
will comprise less than about 300 ppm formaldehyde, preferably less
than about 200 ppm formaldehyde, more preferably less than about
100 ppm formaldehyde, and even more preferably less than about 50
ppm formaldehyde, as measured according to AATCC Test Method
112-1993.
[0045] Some polysiloxanes, generally referred to as silicone oils,
have a liquid form, are not elastomeric and do not self-crosslink.
Silicone oils include, for example, non-reactive linear
polydimethyl siloxanes, that is, siloxanes which are not capable of
further reaction with other silicones and are not capable of a self
curing reaction. Silicone oils have a tendency to produce
non-removable spots on fabrics. In contrast, the silicone
elastomers used in the present invention generally do not produce
such spots. Although the fabrics or treatment compositions may
comprise silicone oil, in one embodiment, the fabrics and treatment
compositions are substantially free of, and preferably are free of,
silicone oil. As used herein, substantially free of silicone oils
means the treatment compositions and fabrics comprise less than 1%,
by weight, silicone oil.
[0046] Thermosetting resins used to impart durable press properties
to fabrics are generally aminoplast resins which are the products
of the reaction of formaldehyde with compounds such as urea,
thiourea, ethylene urea, dihydroxyethylene urea and melamines. As
used herein "aminoplast resins" is intended to include
N-methylolamide cross-linking agents such as dimethylol
dihydroxyethylene urea, dimethylol urea, dimethylolethylene urea,
dimethylol propylene urea, dimethylol methyl carbamate, dimethylol
n-propylcarbamate, dimethylol isopropylcarbamate trimethylolated
melamine, and tris(methoxymethol) melamine. Preferably, the
fabrics, methods and formaldehyde treatment compositions of the
invention are substantially free of, and more preferably are free
of, aminoplast resins and N-methylol cross-linking agents. As used
herein, "substantially free" of aminoplast resins and N-methylol
cross-linking agents is intended to mean the fabrics and treatment
solutions comprise less than about 0.5%, by weight, aminoplast
resin or methylol cross-linking agent.
[0047] Prior to treatment with the formaldehyde composition and
silicone elastomer or precursor thereof, the fabric may optionally
be prepared using any fiber, yarn, or textile pre-treatment
preparation techniques known in the art. Suitable preparation
techniques include brushing, singeing, desizing, scouring,
mercerizing, and bleaching. For example, fabric may be treated by
brushing which refers to the use of mechanical means for raising
surface fibers which will be removed during singeing. The fabric
may be then be singed using a flame to burn away fibers and fuzz
protruding from the fabric surface. Textiles may be desized, which
refers to the removal of sizing chemicals such as starch and/or
polyvinyl alcohol, that are put on yarns prior to weaving to
protect individual yarns. The fabrics may be scoured, which refers
to the process of removing natural impurities such as oils, fats
and waxes and synthetic impurities such as mill grease from
fabrics. Mercerization refers to the application of high
concentrations of sodium hydroxide to a fabric to alter the
morphology of fibers, particularly cotton fibers. Fabrics may be
mercerized to improve fabric stability and luster. Finally,
bleaching refers to the process of destroying any natural color
bodies within the natural fiber. A typical bleaching agent is
hydrogen peroxide.
[0048] The various preparation techniques are optional and
dependent upon the desired final product. For example, when the
final fabric is to be dyed a dark color, there may be no need to
bleach the substrate. Similarly, there may be no need to desize a
knit which was prepared without using any sizing agents, and no
need to separately scour knits and woven textiles as the scouring
may be done during bleaching.
[0049] The following examples are set forth to demonstrate the
methods of the present invention and the good water absorbency
which is obtained in fabrics by the methods of the present
invention. Throughout the examples and the present specification,
parts and percentages are by weight unless otherwise specified. The
following examples are illustrative only and are not intended to
limit the scope of the methods and fabrics of the invention as
defined by the claims.
EXAMPLE 1
[0050] In this example, rayon fabric samples are provided with a
formaldehyde crosslinking treatment in accordance with the
invention. Generally, each fabric is contacted with an aqueous
solution comprising about 10% to 20% formalin, a weight ratio of
formalin to catalyst solution of about 18:5, and about 3% (solids)
of a silicone elastomer commercially available from General
Electric under the designation GE SM2112. The aqueous solution is
padded on the fabric to provide a moisture content of greater than
about 30% and the treated fabric is heated at a temperature greater
than about 300.degree. F. for a period of time sufficient to effect
crosslinking of the formaldehyde with the cellulose in the rayon
fabrics.
EXAMPLE 2
[0051] In this example, the water absorbency properties of various
fabrics are measured according to AATCC Method 79-1995. Generally,
a drop of water is placed on the fabric surface and the time taken
for the specular reflection of the drop to disappear is measured as
an indication of the water absorbency of the fabric. The shorter
the time, the better the water absorbency of the fabric.
[0052] Three fabrics are provided with a formaldehyde crosslinking
treatment according to the methods of the invention as described in
Example 1 and are subjected to measurement of their water
absorbency properties. The first fabric comprises a Tencel.RTM.
lyocell fabric, the second fabric comprises an 85/15 rayon/flax
blend, and the third fabric comprises 100% viscose rayon fabric,
all of which are treated generally in accord with the method
described in Example 1. An aqueous bath solution comprising about
35% formalin, 10% of a 30% catalyst solution and 5% of a silicone
elastomer, Glosil ECR from Glotex Chemical, is employed. The
solution further comprises about 1% of a wetting agent. The treated
fabrics are cured at about 350F. For comparison purposes, untreated
samples of each fabric and samples of each fabric provided with a
conventional aminoplast resin and silicone softener combination
treatment are also subjected to measurement of their water
absorbency properties. The aminoplast treated fabric samples are
prepared using a bath solution comprising a conventional aminoplast
resin, BF Goodrich Free Res 845 (6%), a conventional cationic fatty
amide softener, Fabritone HC (8%), and silicone elastomer/softener,
Glosil ECR (2%) from Glotex Chemical. The bath solution further
comprises about 1% of a wetting agent.
[0053] The water absorbency of each fabric type is measured
initially, before any laundering of the treated or untreated
fabric, after one wash cycle at 60.degree. F., after five wash
cycles at 60.degree. F., after one wash cycle at 95.degree. F., and
after five wash cycles at 95.degree. F. The water absorbency of
five samples of each fabric type are measured at the specified
conditions and the average of the measured values in seconds is set
forth in Table 1, with the standard deviation of the measured
values being set forth in parentheses.
1TABLE 1 Water Absorbency, Seconds No wash One Wash, Five Washes,
One Wash, Five Washes, Fabric Sample cycle 60.degree. F. 60.degree.
F. 95.degree. F. 95.degree. F. Tencel .RTM. lyocell, <1 <1
<1 <1 <1 untreated Tencel .RTM. lyocell, 16.8 11.6 3.6
15.5 2.4 formaldehyde treated (3.7) (1.1) (0.5) (3.4) (0.4) Tencel
.RTM. lyocell, 4.1 >360 325.8 >360 >360 aminoplast resin
treated (0.8) (101.4) Rayon/flax, untreated <1 <1 <1 <1
<1 Rayon/flax, 48.7 70.4 23.6 203.4 57.0 formaldehyde treated
(11.7) (17.1) (4.2) (90.6) (9.0) Rayon/flax, aminoplast 10.8
>360 >360 >360 >360 resin treated (2.3) Viscose Rayon,
<1 <1 <1 <1 <1 untreated Viscose Rayon, 24.8 65.5
27.9 >360 173.2 formaldehyde treated (5.8) (8.1) (6.3) (67.5)
Viscose Rayon, 5.5 >360 >360 >360 >360 aminoplast resin
treated (2.0)
[0054] As is evident from the results set forth in Table 1, the
untreated fabrics all absorb water very rapidly, regardless of the
number of washings to which they were subjected. However, these
untreated materials are disadvantageous as they do not exhibit good
durable press properties and/or good shrinkage resistance and/or,
as often in the case of Tencel.RTM., do not exhibit good appearance
after laundering. The fabrics treated according to the present
methods (formaldehyde treated) all exhibit good water absorbency,
both before and after one or more washings. These fabrics are also
advantageous in that they exhibit good durable press properties and
good shrinkage resistance. Finally, while the aminoplast resin
treated fabrics exhibit good water absorbency properties prior to
washing, it is believed that this good water absorbency is due to
the presence of residual wetting agent from the aqueous resin
treatment on the fabric surface. Once the aminoplast resin-treated
fabrics are subjected to washing, wherein residual wetting agent is
removed, the fabrics exhibit extremely poor water absorbency. One
skilled in the art will appreciate that the times of greater than
360 seconds indicate that the fabrics exhibit poor water
absorbency.
EXAMPLE 3
[0055] In this example, various rayon fabrics are tested for their
water absorbency according to AATCC Test Method 79-1995 as
described in Example 2. The fabrics are also tested for their
durable press properties according to AATCC Test Method 124-1996
after one wash cycle, and for their shrinkage according to AATCC
Test Method 135-1995 after one wash cycle. Viscose, modal and
lyocell rayon fabrics are tested. The fabric type and treatment
chemistry applied to each of rayon fabric samples 1-17 of this
example are set forth in Table 2, together with the various test
results.
2TABLE 2 Water Absorbency, seconds Absorbency, Absorbency, Durable
Shrinkage, Rayon no wash 1 wash cycle, Press % warp x % Sample
Fabric Treatment Chemistry cycles 95.degree. F. rating fill 1
Viscose Aminoplast resin (15%).sup.1 <1 <1 2.0 3.8 .times.
1.5 2 Viscose Aminoplast resin (7.5%) <1 <1 1.1 9.4 .times.
6.0 3 Viscose Aminoplast resin (22%) <1 <1 1.5 2.8 .times.
1.4 4 Viscose Untreated <1 <1 1.0 10.8 .times. 7.5 5 Viscose
Aminoplast resin (15%) + >270 >300 2.1 3.8 .times. 3.7 Si
softener (3%).sup.2 6 Viscose Aminoplast resin (15%) + <1 <1
2.4 4.1 .times. 1.6 PE softener (3%).sup.3 7 Viscose Aminoplast
resin (15%) + 100 >300 1.9 3.9 .times. 3.4 Si softener (3%) + PE
softener (3%) 8 Viscose Aminoplast resin (15%) + 93 >300 2.5 3.4
.times. 1.8 Si softener (4.5%) + PE softener (4.5%) 9 Viscose
Aminoplast resin (15%) + 70 >300 1.9 3.7 .times. 1.7 Si softener
(6%) + PE softener (6%) 10 Viscose Si softener (3%) + PE >300
>300 2.1 5.2 .times. 0.9 softener (3%) 11 Viscose Formalin
(27.7%) + 12 3.1 0.9 .times. 0.2 silicone elastomer.sup.4 (3%) 12
Viscose Aminoplast resin (15%) + 15 20 2.7 3.4 .times. 1.8 silicone
elastomer (3%) 13 Viscose Aminoplast resin (15%) + 62 67 2.4 3.5
.times. 2.3 silicone elastomer (3%) + PE softener (3%) 14 Modal
Aminoplast resin (15%) + >300 >300 2.7 1.7 .times. 1.0 Si
softener (3%) + PE softener (3%) 15 Modal Formalin (27.7%) + <1
16 4.1 +0.1 .times. 0.0 silicone elastomer (3%) 16 Lyocell
Aminoplast resin (15%) + 88 >300 2.9 0.3 .times. +0.2 Si
softener (3%) + PE softener (3%) 17 Lyocell Formalin (27.7%) +
<1 6 3.1 0.2 .times. 0.1 silicone elastomer (3%) .sup.1B.F.
Goodrich Free Res 845 reactant (contains catalyst, self buffered
and low FA) .sup.2High Point Chemical cationic silicone softener
emulsion, Sil-Fin WHP .sup.3Gencorp high density polyethylene
emulsion, Mycon HD .sup.4General Electric SM2112 silicone elastomer
.sup.5Warp and fill generally correspond with length and width,
respectively
[0056] It will be apparent that samples 11, 15 and 17 are according
to the present invention and are treated with both formaldehyde
(formalin) and silicone elastomer. Although not specified in Table
2, a catalyst is employed in an approximately 3:1 ratio with the
formaldehyde. Water absorbency is tested prior to any washing of
the fabric and after one wash cycle conducted at about 95F. As is
apparent from Table 2, the rayon fabric samples of samples 11, 15
and 17 according to the invention exhibit excellent water
absorbency, particularly after washing, good durable press and good
shrinkage resistance.
[0057] With respect to the comparative fabric samples 1- 10, 12-14
and 16, it is important to note that neither the resin treated
samples 1-3, 5-9, 12-14 and 16 nor the non-resin-treated samples 4
and 10 exhibit the superior dimensional stability, i.e., shrinkage
resistance, which are exhibited by the fabric samples 11, 15 and 17
according to the invention. Similarly, none of the comparative
samples 1-10, 12-14, and 16 exhibit the good durable press
properties which are exhibited by the fabric samples 11, 15 and 17
according to the invention. Thus, while samples 1-4, 6, 12 and 13
exhibit good water absorbency, these fabrics are unacceptable for
consumer use owing to their dimensional instability and/or inferior
durable press properties. On the other hand, comparative fabric
samples 5, 7-10, 14 and 16 are further unacceptable for consumer
use in view of their very poor water absorbency. One skilled in the
art will recognize that water absorbency times of greater than
about 300 seconds indicate that the fabrics exhibit poor water
absorbency. As discussed above, it is believed that the combination
of softeners with the aminoplast resin, particularly silicone
softeners which are conventionally used to improve the feel of
aminoplast resin-treated fabrics, contribute to the poor water
absorbency of the fabrics.
[0058] Thus, the advantages of the rayon fabric samples 11, 15 and
17 according to the present invention which exhibit good water
absorbency in combination with good dimensional stability,
particularly shrink resistance, and good durable press properties
are evident.
[0059] The examples and specific embodiments set forth herein are
for illustrative purposes only and are not intended to limit the
scope of the methods and fabrics of the invention. Additional
methods and fabrics within the scope of the claimed invention will
be apparent to one of ordinary skill in the art in view of the
teachings set forth herein.
* * * * *