U.S. patent application number 10/308801 was filed with the patent office on 2003-07-10 for process to prepare polymeric fibers with improved color and appearance.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. Invention is credited to Gallucci, Robert R., Roark, Milton Keith, Studholme, Matthew B..
Application Number | 20030129398 10/308801 |
Document ID | / |
Family ID | 24421831 |
Filed Date | 2003-07-10 |
United States Patent
Application |
20030129398 |
Kind Code |
A1 |
Gallucci, Robert R. ; et
al. |
July 10, 2003 |
Process to prepare polymeric fibers with improved color and
appearance
Abstract
The use of a sulfonated salt polyester ionomer resin in a
colored, drawn polyamide or polyester fiber results in improved
color strength and appearance. Sodium sulfo isophthalate
polybutylene terephthalate copolymers when melt blended with
colorants and subsequently used to make melt spun synthetic
polyamides or polyesters fibers are shown to enhance color strength
in drawn fibers.
Inventors: |
Gallucci, Robert R.; (Mt.
Vernon, IN) ; Studholme, Matthew B.; (Abingdon,
VA) ; Roark, Milton Keith; (Bristol, VA) |
Correspondence
Address: |
HANH T. PHAM
General Electric Company
One Plastics Avenue
Pittsfield
MA
01201
US
|
Assignee: |
GENERAL ELECTRIC COMPANY
PRISMA FIBERS, INC.
|
Family ID: |
24421831 |
Appl. No.: |
10/308801 |
Filed: |
December 3, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10308801 |
Dec 3, 2002 |
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09604990 |
Jun 28, 2000 |
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6495079 |
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Current U.S.
Class: |
428/375 ;
264/210.6; 264/210.8; 264/211; 264/78; 428/364 |
Current CPC
Class: |
D01F 1/04 20130101; D01F
6/92 20130101; Y10T 428/2933 20150115; D01F 6/90 20130101; Y10T
428/2913 20150115 |
Class at
Publication: |
428/375 ; 264/78;
264/210.6; 264/210.8; 264/211; 428/364 |
International
Class: |
D01D 005/098; D01F
001/04; D01F 006/60; D01F 006/62 |
Claims
We claim:
1. An article having improved colored strength, formed by a process
that comprises the steps of: a) melt blending a colorant with a
water insoluble alkylene aryl polyester sulfonate salt copolymer,
forming a colorant polyester sulfonate mixture, said sulfonate salt
copolymer having metal sulfonate units represented by the formula:
2or the formula:(M.sup.+nO.sub.3S).sub.d--A--(OR"OH).sub.pwherein
p=1-3, d=1-3, p+d=2-6, n=1-5, M is a metal with valency n=1-5, and
A is an aryl group containing one or more aromatic rings where the
sulfonate substituent is directly attached to an aryl ring, R" is a
divalent alkyl group and the metal sulfonate group is bound to the
polyester through ester linkages; b) combining said colorant
polyester sulfonate mixture with a polyamide or polyester resin in
the melt; c) forming said melt into an article.
2. The article of claim 1, wherein the process for forming said
polyamide (or polyester melt into an article comprises the step of
forming filaments from said polyamide or polyester melt blend, and
drawing said filaments into fiber.
3. The article of claim 1, in the form of a cloth, fabric,
filament, floor-cover, textile, fiber, rug, yarn, or carpet.
4. The article of claim 1, wherein the metal sulfonate polyester
copolymer of step (a) of the process to prepare said article has
the following formula: 3where the ionomer units, x, are from 0.1-50
mole %, R is halogen, alkyl, aryl, alkylaryl or hydrogen, R.sup.1
is derived from a diol reactant comprising straight chain,
branched, or cycloaliphatic alkane diols and containing from 2 to
12 carbon atoms, A.sup.1 is a divalent aryl radical.
5. The article of claim 1, wherein R is hydrogen, x=0.5-15 mole
percent, R.sup.1 is C.sub.2-C.sub.8 alkyl, and A.sup.1 is derived
from iso- or terephthalic acid or a mixture of the two.
6. The article of claim 1, wherein p=2, d=1, and M is an alkaline
or alkaline earth metal or zinc.
7. The article of claim 4, wherein the metal sulfonate polyester is
an alkylene polyester wherein A.sup.1 is the residue from a diacid
component of iso- or tere-phthalic acid and derivatives thereof and
R.sup.1 is the residue from a diol component selected from the
group consisting essentially of ethylene glycol, propanediol,
butanediol, or cyclohexanedimethanol, and derivatives thereof.
8. The article of claim 4, wherein the metal sulfonate salt unit is
a sulfo iso- or tere-phthalate.
9. The article of claim 1, wherein the polyamide is selected from
the group consisting of: polyamide 6, polyamide 6,6, polyamide
6,12, polyamide 6,10, polyamide 11, polyamide 12, and mixtures
thereof.
10. The article of claim 1, wherein the polyester is selected from
the group consisting of polyethylene terephthalate, polypropylene
terephthalate, polybutylene terephthalate, polyethylene
naphthanoate, polypropylene naphthanoate, polybutylene
naphthanoate, polycyclohexanedimethanol terephthalate and mixtures
thereof.
11. The article of claim 1, wherein the colorant is selected from
the group consisting of metal oxides, mixed metal oxides, metal
sulfides, zinc ferrites, sodium alumino sulfo-silicate pigments,
carbon blacks, phthalocyanines, quinacridones, nickel azo
compounds, mono azo colorants, anthraquinones and perylenes.
12. The article of claim 1, wherein the colorant is selected from
the group consisting of: carbon black, titanium dioxide, zinc
sulfide, zinc oxide, ultramarine blue, cobalt aluminate, iron
oxides, Pigment Blue 15, Pigment Blue 60, Pigment Brown 24, Pigment
Red 122, Pigment Red 147, Pigment Red 149, Pigment Red 177, Pigment
Red 178, Pigment Red 179, Pigment Red 202, Pigment Red 272, Pigment
Violet 19, Pigment Violet 29, Pigment Green 7, Pigment Yellow 119,
Pigment Yellow 147 and Pigment Yellow 150.
13. The article of claim 1, wherein the colorant is present from
0.1-8.0% by weight of the total composition.
14. The article of claim 1, wherein in step (a) of the process,
said colorant is combined with said water insoluble alkylene aryl
polyester sulfonate salt in a ratio of 10:90 to 70:30.
15. The article of claim 1, wherein in step (a) of the process, the
polyester sulfonate resin is combined with a mixture of various
colorants.
16. The article of claim 1, wherein in step (a) of the process, the
polyester sulfonate resin is combined with a single colorant to
make polyester sulfonate resin color concentrate and several of
these resultant color concentrates, of different colors, are
combined in step (b) of the process, with a polyamide or polyester
resin.
17. A process of claim 1, additionally containing at least one of
an antioxidant, stabilizer, processing aid, antimicrobial, flame
retardant, antiozonants, soilproofing agent, stainproofing agent,
antistatic additive, lubricants, melt viscosity enhancer, or
mixtures thereof.
18. An article having improved colored strength, formed by a
process that comprises the steps of: a) melt blending a polyamide
or polyester resin, a colorant, 0.5-30% water insoluble alkylene
aryl polyester sulfonate salt copolymer, said sulfonate salt
copolymer having metal sulfonate units represented by the formula:
4or the formula:(M.sup.+nO.sub.3S).sub- .d--A--(OR"OH).sub.pwherein
p=1-3, d=1-3, p+d=2-6, n=1-5, M is a metal with valency n=1-5, and
A is an aryl group containing one or more aromatic rings where the
sulfonate substituent is directly attached to an aryl ring, R" is a
divalent alkyl group and the metal sulfonate group is bound to the
polyester through ester linkages; b) forming said melt blend into
an article having improved colored strength.
19. The article of claim 19, wherein step (b) of forming said
article comprises forming said melt blend into filaments and
drawing said filaments into fibers.
20. The article of claim 19, in the form of a cloth, fabric,
filament, floor-cover, textile, fiber, rug, yarn or carpet.
21. A process to prepare a colored article with improved color
strength comprising the steps of: a) melt blending a colorant with
a water insoluble alkylene aryl polyester sulfonate salt copolymer
having metal sulfonate units represented by the formulaL: 5or the
formula:(M.sup.+nO.sub.3S).sub.d--A--(OR"OH).sub.pwhere p=1-3,
d=1-3, p+d=2-6, n=1-5, M is a metal with valency n=1-5, and A is an
aryl group containing one or more aromatic rings where the
sulfonate substituent is directly attached to an aryl ring, R" is a
divalent alkyl group and the metal sulfonate group is bound to the
polyester through ester linkages, to make a colorant polyester
sulfonate mixture; b) combining the colorant polyester sulfonate
mixture with a polyamide or polyester resin in the melt; c) forming
said colored polyamide or polyester mixture into an article.
22. The process of claim 22, wherein said forming said colored
polyamide or polyester mixture into an article comprises forming
said mixture into filaments and drawing said filaments into
fibers.
23. An article formed by the process of claim 22.
24. The article of claim 24, in the form of a cloth, fabric,
filament, floor-cover, textile, fiber, rug, yarn or carpet.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims rights of priority under 35 U.S.C.
119 from U.S. patent application Ser. No. 09/604,990 filed on Jun.
28, 2000.
FIELD OF THE INVENTION
[0002] The invention relates generally to a process to prepare
articles having improved color strength. More particularly, the
invention relates to a process to form articles comprising
melt-colored polyamide or polyester based resins, containing novel
polyester ionomer additive(s) in combination with a colorant
forming a pre-formed color concentrate, for improved color and
aesthetics over articles of the prior art. In one embodiment, the
invention relates to articles in the form of melt-colored
fibers.
BACKGROUND
[0003] Coloration of fibers has a long history, and the science of
dyeing, initially of natural fibers such as flax, cotton and wool,
has been under continuous development since Neolithic times. The
appearance of man-made fibers, e.g., cellulosics, acrylics,
polyamides and polyesters, stimulated further developments in
dyeing, and this method of coloring of fibers and articles made
therefrom continues to be the most-practised technique for the
production of colored fiber-based articles of manufacture.
[0004] In the case of fibers based on the more recent polymers such
as polyolefins, polyamides and polyesters, which are spun from the
melt, there exists an alternative method for coloration, i.e.
addition of the colorant species into said melt and direct
extrusion of colored fibers. While such a process may be carried
out with dyes, it is more often carried out with pigments, although
the said process is popularly known in the industry as "solution
dyeing." The major difference between dyes and pigments is that,
under prevailing processing conditions, pigments are virtually
insoluble in polymers, whereas dyes are soluble (see definitions in
German Standards DIN 55943, 55944 and 55949).
[0005] As the technique of melt-pigmentation has been developed, it
has been demonstrated that fibers made in this way can exhibit
certain advantages over those made by post-spinning dyeing of
fibers. Such advantages include improvements to resistance to
degradation and fading in sunlight; lower susceptibility to fading
and/or yellowing by polluting gases in the atmosphere, such as
ozone and nitrogen oxides; improved resistance to chemicals, either
in dry-cleaning processes or due to accidental spillage; less
leaching or fading of color during laundering or cleaning process
involving water and detergents; and no need for post-spinning
dyeing, or the other processes involved in applying and fixing said
dyes onto/into the fiber.
[0006] However, melt-pigmentation is also considered to have some
disadvantages in terms of the color and appearance obtained in the
final fiber. The fibers are known to those skilled in the art to
exhibit degrees of lustre and low brightness which can render the
said fibers unsuitable in certain applications.
[0007] The color change resulting from the addition of pigments to
polymers is based on the wavelength-dependent absorption and
scattering of light. The appearance and color of the final product
being a combination of these two factors is as described in the
Kubelka-Munk theory (for a description of this theory and the
general concepts of color and its measurement, see "Colour Physics
for Industry", Roderick McDonald (Editor), The Society of Dyers and
Colourists, Bradford, UK, 2.sup.nd edition (1997)). Dyes can only
absorb light and not scatter it, since the physical prerequisite
for scattering (a certain minimum particle size) does not exist in
the case of dyes in molecular solution. These colors are therefore
transparent. In so far as the transparency is attributable to the
dye, complete absorption of the light will result in black shades
and selected absorption in colored shades.
[0008] The optical effect of pigments may in the same way be based
on light absorption. If, however, the refractive index of the
pigment differs appreciably from that of the polymer, which is
almost always the case, and, if a specific particle size range is
present, scattering takes place. In this case, the initially
transparent polymer becomes white and opaque, or if selective
absorption takes place at the same time, colored and opaque.
[0009] No scattering occurs when the particle sizes are very small,
and none or very little if they are very large. With all colored
pigments that selectively absorb, the shade and strength of the
final color is thus influenced by particle size. The transparency
and thickness of the colored substrate may additionally affect the
color strength. While some pigments are available in so-called
transparent grades, e.g., red and yellow iron oxides, a complete
color range across the spectrum is not readily available. Many such
ultra-low particle size colorants are expensive, and difficult to
maintain at high dispersion when compounded into a polymer matrix.
It is also known that very low particle size additives in polymer
melts can exhibit a profound effect on the theological properties
of said melt, resulting in formulations which are difficult to spin
using standard equipment and techniques. Use of large particle size
pigments is not a viable option either, as such additives will
result in blocking of filtration systems and spinneret holes, and
tend to lead to filament breaks in fiber production.
[0010] In any case, a large number of melt-pigmented fiber products
are required to be opaque, and the problem lies in producing opaque
colored fibers with levels of color brightness close to those of
dyed products. Note that a fundamental difference between dyeing
and pigmenting of fibers is that, while dyes are either colored or
absorb all wavelengths, i.e., give black shades, pigmentation
introduces an extra variable in that white pigments are readily
available, whereas there is no such species as a "white dye". The
use of white pigments opens a different range of color
possibilities than can be achieved with dyes alone.
[0011] Another potential problem with particulate colorants in a
polymeric melt-extruded product is the phenomenon of dichroism, or
optical anisotropy. Pigment particles are not necessarily isotropic
in shape, and may be needle-shaped, rod-shaped, or platelets. They
may thus become oriented in a particular direction in processing.
The apparent color then depends on the direction of observation.
The origin of this phenomenon is to be found in the fact that
certain pigments crystallise in crystal systems of low symmetry
resulting in directionally dependant physical properties. As far as
the coloristic properties are concerned, this signifies that the
absorption and scattering constants differ in the various principle
crystallographic axes, i.e. such crystals are optically
anisotropic.
[0012] With regard to the final fiber, as opposed to the pigments
themselves, the appearance of a sample thereof can vary depending
on the angle of illumination and/or observation. Fiber samples are
normally prepared for color and appearance testing by carefully
wrapping the fiber or yarn sample, under conditions of uniform
tension and consistent positioning of the said fibers, around a
flat "card," and assessing the color properties, and more
importantly any differences between said properties and those of
the desired standard sample or data, under standard conditions of
illumination and observation. This may be carried out visually, but
more usually instrumentally. Methods and apparatus for carrying out
the analysis of color and appearance in this manner are well known
to those skilled in the art.
[0013] During such examinations, there are two additional effects
which might be observed if the sample is illuminated or observed at
a number of different angles. U.S. Pat. No. 4,479,718 discloses a
process for multi-angle appearance testing of materials. The total
amount of light reflected from the sample, per unit area, may
change. The perceived color may also change. Unless such effects
are specifically desired for particular aesthetic effects in a
final article of manufacture, the appearance of either may result
in the rejection of the fiber by the prospective customer.
Eradication or reduction of such effects thus is important in
obtaining first quality product.
[0014] U.S. Pat. No. 5,674,948 teaches that that end-capping of the
amino end-groups of polyamides results in improvements to the
brightness of compositions colored with organic pigments which are
capable of themselves reacting with such amino end-groups. N-acetyl
lactam is noted as a particularly preferred end-capper. The effect
is limited to a particular set of organic pigments. The levels of
additive end-capper are also quite high.
[0015] U.S. Pat. No. 4,374,641 discloses use of color concentrates
for coloring thermoplastics via making solutions or dispersions of
pigments and dyes in water or polar organic solvents, e.g.
methanol, with various water dispersible or solvent dispersible
addition or polycondensation polymers to achieve dispersion. Such a
mixture requires removal of the solvent entailing and extra step
and potentially generating waste and emissions.
[0016] There still exists a need for a simple method to provide
pigmented polymeric articles, especially melt-spun fibers, with
improved color and appearance, while still using standard grades of
pigment commonly known to those skilled in the art, as well as
equipment and techniques known to produce melt-pigmented fibers
having desired properties for use in articles such as fabrics,
textiles, carpets, threads, etc.
[0017] Applicants have surprisingly found that the addition of
sulfonated polyester ionomer copolymers results in the production
of polyamide or polyester melt-pigmented fibers which exhibit
improved color and appearance and reduced variation in color and
appearance. The improvement in appearance between two samples can
be measured as color strength.
[0018] Applicants have further found that found that pre-mixing the
colorant with the sulfonated polyester ionomer copolymer, and then
subsequently melt mixing that color concentrate with a polyamide or
polyester resin, and forming the entire mixture into an article
such as a drawn fiber, gives enhanced color appearance as compared
to simply combining all ingredients to make fiber in a single
step.
SUMMARY OF THE INVENTION
[0019] The invention relates to a process to prepare a colored
synthetic polyamide or polyester article with improved color
strength that comprises a) melt blending (i) a base polyamide or
polyester resin with (ii) a colorant system comprising one or more
colorants selected from the set of inorganic and/or organic
colorants, optionally sulfonated salt polyester copolymer carrier
resins for the colorants; and optionally (iii) one or more
sulfonated polyester copolymers; and b) forming an article in the
form of a fiber or a textile from said resin composition.
DESCRIPTION OF THE INVENTION
[0020] Base Polymer Matrix. The polymer used as the base, or
matrix, in the practice of this invention is selected from the set
of polyamides and polyesters.
[0021] Polyamides include those synthesised from lactams,
alpha-omega amino acids, and pairs of diacids and diamines. Such
polyamides include, but are not limited to, polycaprolactam
[polyamide 6], polyundecanolactam [polyamide 11], polylauryllactam
[polyamide 12], poly(hexamethylene adipamide) [polyamide 6,6],
poly(hexamethylene sebacamide) [polyamide 6,10], poly(hexamethylene
dodecanediamide) [polyamide 6,12], and copolymers and blends
thereof.
[0022] In one embodiment of the invention, the polyamide is
polyamide 6. In another embodiment, the polyamide is polyamide
6,6.
[0023] Polyesters include those synthesised from one or more
diacids and one or more glycols. Such polyesters include, but are
not limited to, poly(ethylene terephthalate) [PET], poly(propylene
terephthalate) [PPT], poly(butylene terephthalate) [PBT],
poly(ethylene naphthalate) [PEN], polybutylene naphthanoate [PBN],
polypropylene naphthanoate [PPN], polycyclohexane dimethanol
terephthalate [PCT] and copolymers and blends thereof.
[0024] In one embodiment of the invention, the polyesters are PET,
PBT or PPT.
[0025] Colorants. Colorants used in the practise of this invention
may be selected from the categories of dyes, inorganic or organic
pigments, or combinations thereof. Any number of different
colorants may be used, in any proportions, although it will be
understood by those skilled in the art that the total loading of
colorants in the polymer matrix, and the number of different
colorants used, will be kept to a minimum commensurate with
obtaining the color required. In one embodiment of the invention,
the level of colorants ranges from 0.1 to 8.0% of the total weight
of the article, e.g., the fibers.
[0026] In one embodiment of the invention, inorganic pigments are
used. They include, but are not limited to, metal oxides, mixed
metal oxides, sulfides, aluminates, sodium sulfo-silicates,
sulfates and chromates. Non-limiting examples of these include:
carbon blacks, zinc oxide, titanium dioxides, zinc sulfides, zinc
ferrites, iron oxides, ultramarine blue, Pigment Brown 24, Pigment
Red 101, and Pigment Yellow 119.
[0027] In another embodiment of the invention, organic pigments are
used. Examples of organic pigments include azos, di-azos,
quinacridones, perylenes, naphthalene tetracarboxylic acids,
flavanthrones, isoindolinones, tetrachloroisoindolinones,
anthraquinones, anthanthrones, dioxazines, phthalocyanines, and azo
lakes. Non-limiting examples of these include Pigment Blue 60,
Pigment Red 122, Pigment Red 149, Pigment Red 177, Pigment Red 179,
Pigment Red 202, Pigment Violet 29, Pigment Blue 15, Pigment Green
7, Pigment Yellow 147 and Pigment Yellow 150.
[0028] Polyester ionomers. Polyester ionomers, in the context of
the present invention, are defined as polyester polymers derived
from the reaction residue of an aryl carboxylic acid sulfonate
salt, an aromatic dicarboxylic acid, an aliphatic diol or any of
their ester-forming derivatives. The said polyester ionomers
comprise some monovalent and/or divalent sulfonate salt units
represented by the formula 1A:
(M.sup.n+O.sub.3S).sub.d--A--(C.dbd.O).sub.p--
[0029] or formula 1B:
(M.sup.n+O.sub.3S).sub.d--A--(OR"OH).sub.p
[0030] wherein p=1-3, d=1-3, and p+d=2-6, and A is an aryl group
containing one or more aromatic rings: for example, benzene,
naphthalene, anthracene, biphenyl, terphenyl, oxy diphenyl,
sulfonyl, diphenyl or alkyl diphenyl, where the sulfonate
substituent is directly attached to an aryl ring. These groups are
incorporated into the polyester through carboxylic ester linkages.
The aryl groups may contain one or more sulfonate substituents
(d=1-3) and may have one or more carboxylic acid linkages (p=1-3).
Groups with one sulfonate substituent (d=1) and two carboxylic
linkages (p=2) are preferred. M is a metal, with valency n=1-5.
Preferred metals are alkali metals or alkaline earth metals, where
n=1 or 2. Zinc is also a preferred metal. R" is an alkyl spacer
group: for example, --CH.sub.2CH.sub.2--,
--CH.sub.2CH.sub.2OCH.sub.2CH.sub.2--, --CH(CH.sub.3)CH.sub.2--,
--CH.sub.2CH.sub.2CH.sub.2--,
--CH.sub.2CH.sub.2CH.sub.2CH.sub.2--.
[0031] Typical sulfonate substituents that may be incorporated into
the metal sulfonate polyester copolymer may be derived from the
following carboxylic acids or their ester-forming derivatives:
sodium sulfoisophthalic acid, potassium sulfoterephthalic acid,
sodium sulfonaphthalenedicarboxylic acid, calcium
sulfoisophthalate, potassium 4,4'-di(carbomethoxy)biphenyl
sulfonate, lithium 3,5-di(carbomethoxy)benz- ene sulfonate, sodium
p-carboxymethoxybenzene sulfonate, dipotassium
5-carbomethoxy-1,3-disulfonate, sodio
sulfonaphthalene-2,7-dicarboxylic acid, 4-lithio
sulfophenyl-3,5-dicarboxybenzene sulfonate, 6-sodio
sulfo-2-naphthyl-3,5-dicarbomethoxybenzene sulfonate and
dimethyl-5-[4-(sodiosulfo)phenoxy] isophthalate. Other suitable
sulfonate carboxylic acids and their ester-forming derivatives are
described in U.S. Pat. Nos. 3,018,272 and 3,546,008 herein
incorporated by reference. The most preferred sulfonate polyesters
are derived from lithium or sodium 3,5-dicarbomethoxybenzene
sulfonate.
[0032] In one embodiment of the invention, the ionomer polyester
polymer comprises divalent ionomer units represented by the formula
2:
--(C.dbd.O)--Ph(R)(SO.sub.3.sup.-M.sup.+)--(C.dbd.O)--
[0033] wherein R is hydrogen, halogen, alkyl or aryl, and M is a
metal.
[0034] In another embodiment, the polyester ionomer has the formula
3: 1
[0035] where the ionomer units, x, are from 0.1-50 mole percent of
the polymer with 5 to 13 mole percent being preferred and 8 to 12
mole percent being especially preferred; y is defined to be 100-x
mole %. Most preferably R is hydrogen. It is also preferred that
the polyester sulfonate resin be water insoluble. In general water
insoluble resins will be of high molecular weight (Intrinsic
Viscosity greater than or equal to 0.2 dl/g in 60/40
phenol/tetrachloroethane solution) and have less than 15 mole
percent sulfonate units in the polyester chain. Sulfonate copolymer
polyester resins with IV.gtoreq.0.3 dl/g and with 8-12 mole percent
sulfonate units are preferred.
[0036] Typical glycol or diol reactants, R.sup.1, include straight
chain, branched or cycloaliphatic alkane diols and may contain from
2 to 12 carbon atoms. Examples of such diols include, but are not
limited to, ethylene glycol; propylene glycol, i.e. 1,2- and
1,3-propanediol; butane diol, i.e. 1,3- and 1,4-butanediol;
diethylene glycol; 2,2-dimethyl-1,3-propanediol;
2-ethyl-2-methyl-1,3-propanediol; 1,3-pentanediol; 1,5-pentanediol,
dipropylene glycol; 2-methyl-1,5-pentanediol; 1,6-hexanediol,
dimethanol decalin; dimethanol bicyclooctane; 1,4-cyclohexane
dimethanol and particularly its cis- and trans-isomers; triethylene
glycol, 1,10-decanediol; and mixtures of any of the foregoing. A
preferred cycloaliphatic diol is 1,4-cyclohexane dimethanol or its
chemical equivalent. When cycloaliphatic diols are used as the diol
component, a mixture of cis- and trans-isomers may be used; it is
preferred to have a trans-isomer content of 70% or more. Chemical
equivalents to the diols include esters, such as dialkyl esters,
diaryl esters and the like.
[0037] Examples of aromatic dicarboxylic acid reactants, as
represented by the decarboxylated residue A.sup.1, are isophthalic
acid or terephthalic acid, 1,2-di(p-carboxyphenyl)ethane,
4,4'-dicarboxydiphenyl ether-4,4'-bisbenzoic acid and mixtures
thereof. All of these acids contain at least one aromatic nucleus.
Acids containing fused rings can also be present, such as in 1,4-,
1,5- or 2,6-naphthalenedicarboxylic acids. The preferred
dicarboxylic acids are terephthalic acid, isophthalic acid or
mixtures thereof.
[0038] In one embodiment, the ionomer copolyesters are
poly(ethylene terephthalate) [PET], poly(propylene terephthalate)
[PPT] or poly(1,4-butylene terephthalate) [PBT] ionomers. It is
most preferred that the polyester metal sulfonate salt copolymers
be insoluble in water.
[0039] Also contemplated herein are the above ionomers with minor
amounts, e.g. from about 0.5 to about 15 percent by weight, of
units derived from aliphatic acids and/or aliphatic polyols to form
copolyesters. The aliphatic polyols include glycols, such as
poly(ethylene glycol) or poly(butylene glycol). Such copolyesters
can be made following the teachings of, for example, U.S. Pat. Nos.
2,465,319 and 3,047,539.
[0040] The amount of polyester ionomer(s) used in the practise of
the present invention will vary depending on the types and amounts
of colorants used to obtain any particular color. In one
embodiment, an addition of said polyester ionomers to the melt
formulation for spinning into fiber which produces a final sulfur
level of between about 200 and about 5000 ppm gives excellent
results. In another embodiment, the sulfonate polyester copolymers
are to be used at 0.5 to 30% by weight of the fiber.
[0041] Optional components. Besides the matrix polymers, colorants
and polyester ionomers described above, the formulations used in
the practise of the present invention may contain other components.
These may include, but are not limited to--antioxidants, UV
stabilisers, antiozonants, soilproofing agents, stainproofing
agents, antistatic additives, antimicrobial agents, lubricants,
melt viscosity enhancers, flame retardants and processing aids.
[0042] Processing. Colorants may be added to the matrix polymer in
a variety of ways. This may include direct additions of the
colorant(s) to the matrix polymer, addition of the single pigment
dispersions (i.e., addition of each colorant as a separate
concentrate in a carrier resin), and addition of multiple colorant
dispersions (i.e., addition of a single concentrate of mixed
colorants, providing the desired color or let down into the matrix
polymer, in a carrier resin). The addition method may be carried
out in a single compounding step prior to melt spinning, or may be
carried out on the melt.
[0043] In one embodiment of the invention, the polyester ionomers
are incorporated into the matrix polymer either during a
melt-compounding step prior to fiber spinning, or during the fiber
spinning process itself.
[0044] In a second embodiment of the invention, the polyester
ionomers are first combined with the colorant, or mixture or
colorants, to form a color concentrate which is next incorporated
into the matrix polymer during a melt-compounding step or during
the fiber spinning process. Additional sulfonated salt polyester
copolymers may be added in a separate process to the addition of
the pigments if desired. While the addition of some sulfonated salt
polyester resin to the colored fiber improves the fiber color, the
use of the sulfonated salt polyester copolymer as a pre-compounded
color concentrate gives surprising further improvement to the fiber
color.
[0045] In one embodiment of the invention, colorants are first melt
blended with a sulfonated salt polyester copolymer as described
herein, to form a color concentrate. The color concentrate can be
made using a single colorant, often called a single pigment
dispersion, or a mixture of colorants. In one embodiment, the color
concentrate contains from about 5-70 wt. % colorant. Other
compatible resins may also be added during the preparation of the
color concentrate, including but not limited to, the set consisting
of fiber-forming polyamides or polyesters as described above.
[0046] The color concentrate or several different color
concentrates can then be combined with a polyamide of polyester
resin in a melt process to form a colored filament that is drawn
into a fiber. The color concentrates or mixture of color
concentrates can be combined with the base resin in any number of
ways.
[0047] The color concentrate can be melt processed in a number of
ways known to those skilled in the art. In one embodiment, the
melt-processing is done via extrusion on a single or twin screw
extruder. In a second embodiment, the color concentrate comprises
from 5-70% colorant.
[0048] The color concentrate is used in the preparations of
articles having improved color strength in various forms, including
any of a cloth, flocked cloth, fabric, woven fabric, pile fabric,
knitted fabric, filaments, floor-cover, textile, fiber, rug, yarn,
carpet, and the like.
[0049] In one embodiment of a process to prepare an article having
an improved color in the form of a fiber, the color concentrate
addition is carried out on the melt-spinning apparatus itself at
any stage of the fiber forming process, for example at the extruder
throat, at any addition port on the extruder barrel, at the melt
pump, or at the spinneret chamber. In a second embodiment, the
color concentrate is combined with the fiber forming base resin
prior to introduction to the melt spinning apparatus. In a third
embodiment wherein more than one color concentrate (single pigment
dispersion) is used, more than one addition point is used for the
addition of the color concentrate. In yet a fourth embodiment, the
fibers may contain additional sulfonated salt polyester copolymer
as the carrier resin in the color concentrate to further improve
color or for other for other purposes.
[0050] The separate compounding process and the fiber spinning
process may be carried out using techniques and equipment well
known to those ordinarily skilled in the arts of polymer
compounding and fiber melt-spinning.
[0051] The fibers of this invention have a very fine phase separate
morphology. The phase separation allows the matrix resin to
maintain its desirable mechanical properties. However, given the
phase separation between the matrix resin and the sulfonated salt
polyester the improved, uniform color of the resultant fiber is
especially surprising.
[0052] Article forming process--forming a fiber. In one embodiment
of the invention, the article in the form of fibers are drawn from
the sulfonated polyester blends to achieve the full improvement in
color strength and appearance. The optimum draw ratio will vary
with the exact nature of the fiber matrix, colorant type and
loading, sulfonate polyester type and concentration, fiber diameter
and cross section shape. The draw ratio is defined as the ratio of
the final length to the original length per unit weight of the yarn
resulting from the drawing process. The optimum draw ratio for a
given system can readily be determined by comparing the color
strength of as spun fiber with that of the same fiber drawn under
different conditions. In general a draw ratio from 1.05 to 7.00 may
be used, with a draw ratio of 1.10 to 6.00 being more preferred.
Fiber drawing may be achieved by any standard methods known in the
art. The fiber may be drawn between two godet rolls, or pairs of
rolls, or over a draw pin or pins, or a mixture of the two. The
drawing may be done in single or multiple stages. The fiber is
usually heated to a temperature above the glass transition
temperature prior to, or during, drawing to minimise fiber
breakage, although heating is not a requirement for the invention.
The heating may be carried out via heating of godet rolls, plates,
slits, pins or other means such as use of a heated chamber; hot gas
such as steam, or hot liquid, such as water, may also be used.
Depending on the fiber forming base resin chosen, the preferred
heating device is selected.
[0053] The fibers produced from the practise of the present
invention may be of a range of deniers per filament (dpf) depending
on the ultimate use to which such fibers may be put--low dpf for
textile use, higher dpf for use in carpets. The cross-sectional
shape of the fibers may also be any of a wide range of possible
shapes, including round, delta, trilobal, tetralobal, grooved, or
irregular. These product fibers may be subjected to any of the
known downstream processes normally carried out on melt-spun
fibers, including crimping, bulking, twisting etc., to produce
yarns suitable for incorporation into a variety of articles of
manufacture, such as apparel, threads, textiles, upholstery and
carpets.
EXAMPLES
[0054] These examples are provided to illustrate the invention but
are not intended to limit the scope of the invention in any
way.
[0055] Color Strength Measurements: The color strength is defined
as the color yield or color intensity of a given quantity of a
colorant in a sample ("batch") in relation to a standard, (or
another sample). Higher color strength means a sample has a more
intense color compared to the standard. The higher the color
strength the greater the difference in color intensity compared to
the standard. When samples with the same type and amount of pigment
are compared, as is the case in all examples of this invention, a
higher color strength means that the more intense colored sample
formulation can reach the same intensity as the standard with less
pigment. This allows for more efficient use of the colorant.
[0056] Color strength was determined from the spectrophotometric
data using the (K/S).sub..lambda. summation method, where
(K/S).sub..lambda. (or K/S) is the Kubelka-Munk function, where K
is the absorption coefficient and S is the scattering coefficient.
The % color strength of a sample is defined as the ratio of the sum
of (K/S).sub..lambda. for the sample to the sum of
(K/S).sub..lambda. for the standard expressed as a percentage. A
percentage less than 100% indicates that the sample is less intense
in color strength than the standard; a percentage greater than 100%
indicates that the sample is more intense than the standard.
Further details of the (K/S).sub..lambda. summation method can be
found in "Colour Physics for Industry", Roderick McDonald (Ed.),
The Society of Dyers and Colourists, Bradford, UK, 2.sup.nd edition
(1997).
[0057] In the examples, spectrophotometric measurements were made
using an Optronik Multiflash M45 spectrophotometer and a commercial
color evaluation software package. CIE illuminant D.sub.65 was
used. Prior to the spectrophotometric measurements the yarn was
precisely wound on to a plastic or metal card to produce a card
wrap sample. Sufficient yarn was wound on to the card such that the
card was not visible through the yarn. The color strength was read
from the card wrap sample at measurement angles from the specular
of 20, 25, 35, 45, 55, 65, 75 and 115 degrees. Color Strength
values are the average of all 8 viewing angles. Color strength
measured as percent for the examples of the invention using a SPBT
color concentrate are measured by comparison to the same blend with
no sulfonated polyester (SPBT) or to a fiber where the same amount
of SPBT was added independent of the colorants.
[0058] SPBT (sulfonated polybutylene terephthalate) was made by
polymerization of dimethyl terephthalate, butane diol and dimethyl
sodium sulfo isophthalate. The copolymer contains 13 wt. % sodium
sulfo isophthalate. It has an intrinsic viscosity in 60/40 phenol
tetrachloroethane of 0.45 dl/g. The same SPBT was used in all
examples. This SBPT is water insoluble which facilitates isolation
of the SBPT, subsequent handling as well a fiber production.
[0059] Polyamide Viscosity: The relative solution viscosity (RV) of
the polyamides used in the examples was determined by first
preparing a 0.55% wt. solution of the dried polyamide in 96%
sulfuric acid. Solution flow times were determined in a
Cannon-Ubbelohde size 2 viscometer suspended in a temperature
controlled water bath set at a temperature of 25.degree.
C..+-.0.02.degree. C. The flow times of the sulfuric acid were also
measured. The RV was then calculated by dividing the flow time of
the polyamide solution by the flow time of the sulfuric acid.
Polyamide 6,6 of the examples has a RV of 3.1, and the polyamide 6
has a RV=2.7.
[0060] All yarn denier values have the units g/9000 m.
[0061] The following colorants were used in the examples:
PY147=pigment yellow 147, PB15:1=pigment blue 15:1, PR202=pigment
red 202; PY150=pigment yellow 150, PV29=pigment violet 29,
PBk7=pigment black 7, PBk6=pigment black 6, PW6=pigment white 6,
PR101=pigment red 101, PR179=pigment red 179, PG7=pigment green 7,
PBr24=pigment brown 24, ZnO=zinc oxide (pigment white 4). Cu
Hal=copper halide.
[0062] For the examples of Tables 1-4, colorants were compounded as
concentrates in PA6 or PET.
Examples 1-4 (Table 1)
[0063] Polyamide 6,6 pellets were melt blended with 16 wt. % of a
SPBT copolymer along with polyamide 6 color concentrates as shown
in Table 1, on a single screw extruder at 285.degree. C. All resins
had been dried to below 1000 ppm moisture prior to extrusion. The
resultant extrudate was chopped into pellets, dried and extruded
into fibers on a slow speed spinning line. The fibers were 1850
denier with a trilobal (Y) cross section. Take up speed was 470
m/min. The different colored yarns had 30 filaments per bundle and
are referred to as the 1850/30Y samples. The yarn was then heated
to 170.degree. C. and single stage drawn at a draw ratio of 3.6 to
produce the drawn (1850/30Y DWN) samples. The drawn yarn was then
precision wound onto an aluminium card on which spectrophotometric
measurements were made.
[0064] Control samples where the 16 wt. % SPBT was replaced with
polyamide 6,6 were prepared using the same pigments and the same
process. The yarn samples of the invention were compared to the
controls of the same color and the color strength compared. In
Table 1 it can be seen that the K/S color strength of the drawn
SPBT containing samples is 104 to 135.8% more intense than the
control colors with no SPBT. The improved color strength is
greatest in examples 2 and 4, the ochre and olive colors, but still
significant in the red and teakwood colors (examples 1 and 3).
1TABLE 1 1 2 3 4 Examples Teakwood Ochre Red Olive Color 1850/30Y
DWN 1850/30Y DWN 1850/30Y DWN 1850/30Y DWN Polyamide 6,6 3.1RV/wt.
% 78.966 79.0005 79.5447 79.0329 Polyamide 6 4.8 4.6 3.7 4.7 SPBT
13 wt. % SIP 16.0 16.0 16.0 16.0 Colorants/wt. % PBr24 = 0.0534
PY150 = 0.1873 PY150 = 0.0054 PY150 = 0.10 PR101 = 0.0094 PR101 =
0.0758 PR179 = 0.6063 PG7 = 0.0093 PBk6 = 0.0054 PBk6 = 0.0240 PBk6
= 0.0136 PBk7 = 0.0277 PW6 = 0.0858 PW6 = 0.0324 PW = 0.050 PW6 =
0.0501 ZnO = 0.050 ZnO = 0.050 ZnO = 0.050 ZnO = 0.050 Stabilizer/
wt. % Cu Hal = 0.03 Cu Hal = 0.03 Cu Hal = 0.03 Cu Hal = 0.03 Draw
ratio 3.6 3.6 3.6 3.6 Color Strength K/S 104 112.7 102.1 135.8 SPBT
= 13 wt. % Na sulfoisophthalate PBT copolymer Color Strength with
SPBT vs. control with no SPBT and same pigments
Examples 5-7 Controls A-C (Table 2)
[0065] The formulated pigmented fibers of these examples were
produced in a manner similar to those described above. All
polyamide 6,6 was replaced with polyamide 6 of a RV=2.7. SPBT was
used at 20 wt. % of the formulation (Table 2). Extrusion was run at
250.degree. C. The blends were spun into fibers with a round cross
section on a high speed spinning line to produce fibers of a 250
denier, 25 filaments per bundle (250/25R). The take up speed was
3700 m/min., with a drawdown ration of 470:1. These samples were
then heated at 120.degree. C. and drawn at a draw ratio of 1.25 to
produce the drawn (250/25R DWN) samples. Cardwraps of both, yarns
were prepared for color strength measurements as described
above.
[0066] Both the as-pun and the drawn samples were compared to
control samples that were made by replacing all 20 wt. % SPBT with
polyamide 6. The as-spun SPBT samples (250/25R) and the SPBT drawn
samples (250/25R DWN) were compared to the controls having no SPBT.
As can be seen in Table 2 the DWN samples (examples 5,6 and 7) have
greater color strength (106.8, 104, 105.4) than the drawn controls
with no SPBT. On the other hand the as spun fibers with SPBT
(controls A and B) show inferior color strength to the as spun
controls with no SPBT, (98.3 and 97.6%).
[0067] The red color shows somewhat different behaviour. The as
spun SPBT sample (Control C) shows higher color strength than the
as spun control with no SPBT (102.5%) but the drawn sample with
SPBT (example 7) has even better color strength (105.4%).
[0068] This set of experiments shows the benefit of drawing the
SPBT containing fibers to achieve improved color strength.
2TABLE 2 5 Control A 6 Control B 7 Control C Examples Blue Blue
Ochre Ochre Red Red Color 250/25R DWN 250/25R 250/25R DWN 250/25R
250/25R DWN 250/25R Polyamide 6 wt % 79.3824 79.3824 79.6805
79.6805 79.3247 79.3247 SPBT 13 wt % SIP 20.0 20.0 20.0 20.0 20.0
20.0 Colorants/ wt. % PV29 = 0.0035 PV29 = 0.0035 PY150 = 0.1873
PY150 = 0.1873 PY150 = 0.0054 PY150 = 0.0054 PB15:1 = 0.6055 PB15:1
= 0.6055 PR101 = 0.0758 PR101 = 0.0758 PR179 = 0.6063 PR179 =
0.6063 PBk7 - 0.0021 PBk7 - 0.0021 PBk6 = 0.0240 PBk6 = 0.0240 PBk6
= 0.0136 PBk6 = 0.0136 PW6 = 0.0065 PW6 = 0.0065 PW6 = 0.0324 PW6 =
0.0324 PW = 0.050 PW = 0.050 ZnO = 0.050 ZnO = 0.050 ZnO = 0.050
ZnO = 0.050 ZnO = 0.050 ZnO = 0.050 Stabilizer/wt. % Cu Hal = 0.03
Cu Hal = 0.03 Cu Hal = 0.03 Cu Hal = 0.03 Cu Hal = 0.03 Cu Hal =
0.03 Draw ratio 1.25 as spun 1.25 as spun 1.25 as spun Color
Strength K/S 106.8 98.3 104 97.6 105.4 102.5 SPBT = 13 wt. % Na
sulfoisophthalate PBT copolymer Color Strength with SPBT vs.
control with no SPBT and same pigments
Examples 8-10 Control D (Table 3)
[0069] Polyamide 6,6 pellets were extruded with 15 wt. % SPBT and 4
wt. % of a 25:75 Pigment Yellow 150 (PY150):polyamide 6 color
concentrate (batch 1) by weight at 285.degree. C. All materials had
been dried to less than 1000 ppm moisture before extrusion. The
chopped extrudate was melt spun into fibers on a slow speed
spinning line to produce an undrawn yarn of 2100 denier at a take
up speed of 470 m/min. The fibers had a trilobal (Y) cross section
and 34 filaments per bundle. The yarn was then drawn at 170.degree.
C. at a draw ratio of 3.6 to produce the 2100/34Y DWN samples shown
in Table 3.
[0070] A control sample with added polyamide 6,6 replacing the 15
wt. % SPBT was prepared with the same color concentrate in the same
manner. The drawn SPBT yarn was compared to the drawn control with
no SPBT. Example 8 shows a color strength improved to 129% in the
SPBT containing yarn.
[0071] The experiment was then repeated with a different 25:75
PY150/polyamide 6 color concentrate (batch 2). It is known that
different batches of color concentrates often give different color
strengths even when used in the same formulation processed under
similar conditions. Example 9 shows the color strength of a drawn
yarn using PY150 batch 2 compared to a control using no SPBT made
with PY150 batch 2. The color strength is improved to 115.6%.
[0072] In order to further examine the color differences between
the two PY150 color concentrate batches two experiments were
performed. The drawn 2100/34Y fiber made with no SPBT using PY150
batch 1 was compared to the same composition using PY150 batch 2
(Control D). A color strength value of only 89.1% indicates a large
difference in color intensity between the two samples. These two
samples would be expected to give similar color strengths. In
practice in order to use batch 2 to make fibers of the same yellow
color it would be necessary to adjust the amount of color
concentrate. This adjustment would result in more difficulty in
making fibers of matching colors. Batch to batch variation of fiber
colors would be very detrimental to the manufacture of uniform
woven, knitted or pile textiles, carpets or floorcoverings.
[0073] When the same two batches of PY150 polyamide 6 concentrate
were used to color a polyamide 6,6 2100/34Y DWN drawn fiber sample
with 15 wt. % SPBT there is much less variation in the color
strength. Example 10 compares the color strength of a drawn fiber
made with 15 wt. % SPBT and PY150 batch 2 concentrate to the same
type of drawn fiber made with the batch 1 concentrate. The color
strength of the batch 2 sample compared to the batch 1 sample is
98.5% indicating that the two samples are closely color
matched.
3TABLE 3 8 9 Control D 10 Examples PY150 PY150 PY150 PY150 Color
2100/34Y DWN 2100/34Y DWN 2100/34Y DWN 2100/34Y DWN Polyamide 6,6
3.1RV/wt. % 81.0 81.0 96.0 81.0 Polyamide 6/ wt. % 3.0 3.0 3.0 3.0
SPBT 13 wt. % SIP 15.0 15.0 0 15.0 PY150 Batch 1/wt. % 1.0 0 1.0 0
PY150 Batch 2/wt. % 0 1.0 0 1.0 Draw ratio 3.6 3.6 3.6 3.6 Color
Strength K/S 129.4 115.6* 89.1** 98.5*** SPBT = 13 wt. % Na
sulfoisophthalate PBT copolymer Color Strength with SPBT vs.
control with no SPBT and same pigments *= Color Strength PY150
batch 2 with SPBT vs. PY150 Batch 1 no SPBT **= Color Strength
PY150 batch 1 no SPBT vs. PY150 Batch 2 no SPB ***= Color Strength
PY150 batch 2 with SPBT vs. PY150 Batch 1 with SPBT
Examples 11-12 Controls E-F (Table 4)
[0074] These examples extend the invention to PET fibers. In this
case PET pellets (IV=0.67 dl/g) were combined with 15 wt. % SPBT
and the indicated single pigment concentrates. PET was used as the
carrier resin for the concentrates. This mixture of pellets was
ground to a fine powder and dried to less than 50 ppm moisture and
extruded into filaments at 285.degree. C. at a take up speed of
3250 m/min. As indicated in Table 4 two colors were made. The
fibers were 255 and 170 denier with a round cross section with 34
filaments per bundle. A similar set of fibers was prepared using
the same pigments but replacing the SPBT with PET.
[0075] Example 11 compares a drawn navy color SPBT blend with a
drawn control having no SPBT. Color Strength is improved to 111.2%.
In a yellow color the drawn SPBT blend shows a color strength of
106.0% compared to a drawn control with no SPBT (example 12).
[0076] Control examples E and F show that the as spun fibers with
SPBT, with no drawing, do not show the enhanced color strength
achieved in the SPBT containing drawn fibers of the invention.
4TABLE 4 11 Control E 12 Control F Examples Navy Navy Sunstraw
Sunstraw Color 170/34R DWN 170/34R 255/34R DWN 255/34R PET 0.67
IV/wt. % 83.179 83.179 84.0109 84.0109 SPBT 13 wt. % SIP 15.0 15.0
15.0 15.0 Colorants/wt. % PB15:1 = 0.9218 PB15:1 = 0.9218 PY150 =
0.2758 PY150 = 0.2758 PR149 = 0.6008 PR149 = 0.6008 PR101 = 0.4412
PR101 = 0.4412 PBk7 = 0.2256 PBk7 = 0.2256 PBk6 = 0.0465 PBk6 =
0.0465 PW6 = 0.0728 PW6 = 0.0728 PW6 = 0.2256 PW6 = 0.2256 Draw
ratio 1.25 as spun 1.25 as spun Color Strength K/S 111.2 98.8 106
99.4 SPBT = 13 wt. % Na sulfoisophthalate PBT copolymer Color
Strength with SPBT vs. control with no SPBT and same pigments.
[0077] The colorants listed in table 5 were individually compounded
at 25 wt. % in a 13 wt. % sodium sulfoisophthalate polybutylene
terephthalate copolymer (SPBT). Similar color concentrates were
made compounding the same colorants at the same level using
polyamide 6 of 2.7 RV.
5TABLE 5 Key to Pigment Dispersions: Dispersion ID Pigment Loading
Pigment Carrier PA6/21-1911 25% PR 202 PA6 SPBT/21-1913 25% PR 202
SPBT PA6/31-944 25% PY 147 PA6 SPBT/31-946 25% PY 147 SBPT
PA6/51-2265 25% PB 15:1 PA6 SPBT/51-2267 25% PB 15:1 SPBT
Examples 13-21 (Table 6)
[0078] Single color concentrates of PR202, PY147 and PB15:1 were
prepared by melt blending 25% of the colorant with either SPBT or
polyamide 6 using a twin screw extruder at .about.275.degree. C.
These color concentrates were used in all subsequent
experiments.
[0079] The SPBT and polyamide 6 resins had been dried to below 300
and 1000 ppm moisture respectively prior to extrusion. The
resultant extrudate was stranded and chopped into pellets.
[0080] Uncolored polyamide 6 pellets were melt blended with various
levels of the SPBT color concentrate and compared to similar fibers
with the same level of colorant delivered as a polyamide 6 color
concentrate. All pellets were dried prior to being extruded into
fibers on a high speed spinning line to produce partially oriented
yarn (POY). The fibers were 180 denier with a round (R) cross
section. Take up speed was 4000 m/min. The different colored yarns
had 34 filaments per bundle and are referred to as the 180/34 R
samples. The yarn was then heated to 120.degree. C. and drawn at a
draw ratio of 1.2 to produce drawn 150/34R samples. The card wrap
samples were produced on which spectrophotometric measurements were
made.
[0081] Table 6 (examples 13-21) shows a comparison of the color
strength of polyamide 6 fibers made using a polyamide 6 color
concentrate at various pigment loading compared to the fiber made
with the same level of colorant introduced as a SPBT concentrate.
If the two fibers had the same color strength the % difference
would be 100%. Higher color strength shows a more intense color at
the same colorant loading.
[0082] For the three pigment loadings (0.25% pigment=1% color
concentrate, 0.5% pigment=2% color concentrate and 1.0% pigment=4%
color concentrate) of PR202, PY147 and PB15:1 the SPBT carrier give
significantly better (104 to 166%) color in the polyamide 6 fibers
than the polyamide 6 carrier.
6TABLE 6 Example Standard Batch Colorant % Pigment in Fiber % Color
Strength 13 PA6/21-1911 SPBT/21-1913 PR 202 0.25 166 14 PA6/21-1911
SPBT/21-1913 PR 202 0.50 157 15 PA6/21-1911 SPBT/21-1913 PR 202
1.00 150 16 PA6/31-944 SPBT/31-946 PY 147 0.25 119 17 PA6/31-944
SPBT/31-946 PY 147 0.50 119 18 PA6/31-944 SPBT/31-946 PY 147 1.00
104 19 PA6/51-2265 SPBT/51-2267 PB 15:1 0.25 123 20 PA6/51-2265
SPBT/51-2267 PB 15:1 0.50 129 21 PA6/51-2265 SPBT/51-2267 PB 15:1
1.00 116
Examples 22-30 (Table 7)
[0083] Table 7 shows polyamide 6 fibers prepared under the same
conditions as examples 13-21. The yarn samples of the invention
were compared to the controls of the same color and color strength
differences determined. In Table 7, it can be seen that the color
strength of the samples prepared using a SPBT color concentrate is
119 to 157% more intense than the control colors with no SPBT
(examples 23, 26 & 29).
[0084] Example 22 compared a polyamide fiber made with 2% of the
PR202 polyamide 6 color concentrate (PA6/21-1911) with 1.5% SPBT to
a polyamide 6 fiber made with the same level of pigment red 202
with no SPBT. There is a small improvement in color strength to
109%. However, if the same level of SPBT is used as a pigment red
carrier (SPBT/21-1913), the resultant polyamide 6 fiber has much
greater color strength (157%) compared to the polyamide 6 fiber
made using the polyamide 6 color concentrate (example 23) or the
polyamide 6 color concentrate with SPBT added separately (example
24). In all cases, the colorant loading is the same.
[0085] In example 24, the compositions of the two fibers being
compared are identical but by first combining the SPBT with the
pigment red 202 into a color concentrate (SPBT/21-1913) much better
fiber color strength (153%) is achieved than simply adding the SPBT
when making the fiber using a polyamide color concentrate
[0086] In a similar fashion, polyamide 6 fibers were made using
0.5% pigment yellow 147 in fiber. The PY147 SPBT concentrate
(SPBT/31-946) give a stronger color (119%) in a polyamide 6 fiber
than the PA6/31-944 concentrate (Example 26) or than the polyamide
6 concentrate with SPBT added separately (example 27, color
strength 166%).
[0087] Simply adding 1.5% SPBT to the fiber mixture with polyamide
6 color concentrate improved the color strength to only 101%
(example 25).
[0088] Pigment Blue 15:1 colored polyamide 6 fibers show a similar
trend. Use of a 25% blue SPBT concentrate (SPBT/51-2267) in the
polyamide fiber at 2.0% gave color strength of 129% compared to the
polyamide 6 color concentrate (example 29). Addition of SPBT along
with the polyamide 6 color concentrate (PA6/51-2265) did not give
the same color strength as the use of the same amount of SPBT as
the color carrier resin example 30).
7TABLE 7 % Pigment % Color Example Standard Batch Colorant in Fiber
Strength 22 PA6/21-1911 PA6/21-1911 + 1.5% SPBT PR 202 0.50 109 23
PA6/21-1911 SPBT/21-1913 PR 202 0.50 157 24 PA6/21-1911 + 1.5% SPBT
SPBT/21-1913 PR 202 0.50 153 25 PA6/31-944 PA6/31-944 + 1.5% SPBT
PY 147 0.50 101 26 PA6/31-944 SPBT/31-946 PY 147 0.50 119 27
PA6/31-944 + 1.5% SPBT SBPT/31-946 PY 147 0.50 166 28 PA6/51-2265
PA6/51-2265 + 1.5% SPBT PB 15:1 0.50 90 29 PA6/51-2265 SPBT/51-2267
PB 15:1 0.50 129 30 PA6/51-2265 + 1.5% SPBT SPBT/51-2267 PB 15:1
0.50 161
Examples 31-39 (Table 8)
[0089] The formulated pigmented fibers of these examples were
produced in a manner similar to those described above but using
polyamide 6,6 as the fiber forming resin. Extrusion was done at
285.degree. C. The blends were spun into fibers with addition of
either a 25% color concentrate based on polyamide 6 or SPBT. Fibers
were made with a trilobal (Y) cross section on a slow speed
spinning line to produce fibers of an 1850 denier, 30 filaments per
bundle (1850/30Y). The take up speed was 470 m/min. These samples
were then heated at 170.degree. C. and drawn at a draw ratio of 3.6
to produce drawn 514/30Y samples. Card wrap samples were prepared
for color strength measurements.
[0090] Example 31 shows only a slight improvement in color when
1.5% SBPT is added to a PR202 (red) fiber compared to a fiber made
using a polyamide 6 color concentrate. Example 32 shows higher
color strength (134%) when the SBPT is used in a pre-formed color
concentrate (SPBT/21-1913).
[0091] Example 33 shows that the use of SBPT to make a preformed
concentrate gives a red polyamide 6,6 fiber with 132% color
strength compared to adding the same amount of SPBT to the fiber
with a polyamide 6 color concentrate (PA6/21-1911)
[0092] In a yellow polyamide 6,6 fiber, the addition of SPBT with
polyamide 6 color concentrate gives a color strength of 101%
compared to the blend with no SPBT (example 34). However in this
case (example 35), the SPBT color concentrate gives no color
strength (100%) compared to the polyamide 6 color concentrate. This
shows that the effect of the SBPT on improving color will, to some
extent, be effected by the colorant, the matrix resin, the
processing conditions and the concentration.
[0093] Example 36 shows that use of the SPBT in a concentrate gives
improved color strength (112%) compared to addition of the same
level of SPBT with a polyamide 6 concentrate.
[0094] In blue polyamide 6,6 fiber, the SPBT concentrate gives 114%
color strength compared to the polyamide 6 concentrate (example
38). Addition of SPBT with the polyamide 6 concentrate gives 110%
color strength (example 37) and the SPBT added as a concentrate
gives 106% color strength compared to addition of the same amount
of SPBT with a polyamide 6 color concentrate (example 39).
8TABLE 7 % Pigment % Color Example Standard Batch Colorant in Fiber
Strength 31 PA6/21-1911 PA6/21-1911 + 1.5% SPBT PR 202 0.50 101 32
PA6/21-1911 SPBT/21-1913 PR 202 0.50 134 33 PA6/21-1911 + 1.5% SPBT
SPBT/21-1913 PR 202 0.50 132 34 PA6/31-944 PA6/31-944 + 1.5% SPBT
PY 147 0.50 101 35 PA6/31-944 SPBT/31-946 PY 147 0.50 100 36
PA6/31-944 + 1.5% SPBT SBPT/31-946 PY 147 0.50 112 37 PA6/51-2265
PA6/51-2265 + 1.5% SPBT PB 15:1 0.50 110 38 PA6/51-2265
SPBT/51-2267 PB 15:1 0.50 114 39 PA6/51-2265 + 1.5% SPBT
SPBT/51-2267 PB 15:1 0.50 106
* * * * *