FIELD OF THE INVENTION
[0001] The present invention relates to a process for the production of fibers having a
diameter of less than 200 microns comprising a first component comprising a thermoplastic
polymer and a second component comprising thermoplastic starch wherein the second
component is not encompassed by another component or components or if encompassed
by another component or components then the second component encompasses a hollow
core. Such fibers allow for removal of the second component by exposure to a solvent
for the second component.
BACKGROUND OF THE INVENTION
[0002] Current woven and nonwoven materials are commonly produced from multicomponent fibers
where one component is removed in order to produce fibers with desired diameter or
denier, such as in a splittable or islands-in-a-sea configuration for use in synthetic
leather, for example. Many of materials removed are derived from petroleum, most notably
polyesters or nylons, through treatment processes that are not environmentally friendly.
These polymeric materials are not biodegradable and potentially pose a long term problem
in waste disposal systems. There is a need for a removable component in those multicomponent
fibers that is more environmentally friendly, affordable and that can be made in conjunction
with conventional thermoplastic polymers that can deliver softness at affordable costs.
[0003] Multicomponent fibers that include starch as a component are desirable since starch
is a renewable raw material, of low cost, and is independent of petroleum products.
It is important that fibers having starch as a component be processible on standard
equipment and use existing technology.
[0004] The present invention addresses this need for a removable fiber component that is
environmentally friendly as well as providing good processing characteristics during
manufacture.
SUMMARY OF THE INVENTION
[0005] The present invention is directed to a process of producing a melt spinnable fiber
having a diameter of less than 200 microns, comprising: compounding a first component
comprising a thermoplastic polymer; compounding a second component comprising destructured
starch having a molecular weight in the range from 10,000 g/mol to 5,000,000 g/mol
and an agent selected from the group consisting of an acid substituted vinyl polymer,
a polyolefin carboxylic acid copolymer, a polyhydroxyetherester, a polyhydroxyetheramide,
a C8-C22 aliphatic saturated or unsaturated carboxylic acid, an aliphatic carboxyamide,
and an aromatic carboxyamide; spinning the first component with the second component
to form a fiber having a diameter of less than 200 microns, wherein the second component
is not encompassed by another component or components or if encompassed by another
component or components then the second component encompasses a hollow core; and contacting
the fiber with a solvent for the second component, wherein the second component is
removed from the fiber by exposure to the solvent at a rate that is slower than that
of a fiber lacking the agent.
[0006] In accordance with an embodiment of the invention the process further comprises physically
manipulating the fiber prior to complete removal of the second component. Preferably
the physical manipulation of the fiber consists of elongating the fiber or forming
the fiber into a fabric.
[0007] The configuration of the multicomponent fibers can be sheath-core, islands-in-the-sea,
side-by-side, ribbon, segmented pie, for example, or various combination thereof.
In a sheath-core configuration, for example, the second component is the sheath, and
is removable by exposure to a second-component-removing solvent. In a configuration
having a hollow core, the second component may encompass the hollow core.
[0008] The fiber compositions are cost-effective and suitable for use in commercially available
equipment, while possessing a significant amount of the total composition that is
biodegradable, thus eliminating hazardous and non-environmentally friendly materials
from such processes. The present invention is also directed toward making durable
fibers for a woven, knitted or other suitable fabric making process. The present invention
is also directed to nonwoven webs and disposable articles comprising said fibers.
BRIER DESCRIPTION OF THE DRAWINGS
[0009] These and other features, aspects, and advantages of the present invention will become
better understood with regard to the following description, appended claims, and accompanying
drawings where:
Fig. 1A - Fig. 1I provide schematic drawings illustrating cross-sectional views of
multicomponent fibers.
Fig. 1A illustrates a typical concentric sheath-core configuration.
Fig. 1B illustrates a shoath-core configuration with a solid core and shaped continuous
sheath.
Fig. 1C illustrates a sheath-core configuration with a hollow core, core x, and continuous
sheath y.
Fig. 1D illustrates a sheath-core configuration with a hollow core, core x, and shaped
continuous sheath y.
Fig. 1E illustrates a discontinuous sheath-core configuration.
Fig. 1F illustrates a further discontinuous sheath-core configuration.
Fig. 1G illustrates a sheath-core configuration with hollow core surrounded by component
X and discontinuous sheath component Y.
Fig. 1H illustrates a further sheath-core configuration with hollow core surrounded
by component X and discontinuous sheath component Y.
Fig. 1I illustrates an eccentric sheath-core configuration.
Fig. 2A - Fig. 2B provide schematic drawings illustrating cross-sectional views of
bicomponent fibers having a segmented pie configuration.
Fig. 2A illustrates a solid eight segmented pie configuration.
Fig. 2B illustrates a hollow eight segmented pie configuration.
Fig. 3 provides a schematic drawing illustrating a cross-sectional view of a bicomponent
fiber having a ribbon configuration.
Fig. 4 provides schematic drawings illustrating a cross-sectional view of a bicomponent
fiber having a side-by-side configuration.
Fig. 4A illustrates a side-by-side configuration.
Fig. 4B illustrates a side-by-side configuration with a rounded adjoining line. The
adjoining line is where two components meet. Component Y is present in a higher amount
than Component X.
Fig. 4C illustrates a side-by-side configuration with component Y positioned on both
sides of Component X with a rounded adjoining line.
Fig. 4D illustrates a side-by-side configuration with component Y positioned on both
sides of Component X.
Fig. 4E illustrates a shaped side-by-side configuration with component Y positioned
on the tips of component X.
Fig. 5A - Fig. 5C provide schematic drawings illustrating cross-sectional views of
multicomponent fibers having an islands-in-the-sea configuration.
Fig. 5A illustrates a solid islands-in the-sea configuration with component X surrounded
by component Y. Component X may be triangular in shape.
Fig. 5B illustrates a solid islands-in the-sea configuration with component X surrounded
by component Y.
Fig. 5C illustrates a hollow islands-in the-sea configuration with component X surrounded
by component Y.
Fig. 6 provides a schematic drawing illustrating a cross-sectional view of a tricomponent
fiber having a ribbon configuration.
Fig. 7 provides a schematic drawing illustrating a cross-sectional view of a tricomponent
fiber having a concentric sheath-core configuration with component X comprising the
solid core, component Y comprising the inside continuous sheath, and component Z comprising
the outside continuous sheath.
Fig. 8 provides a schematic drawing illustrating a cross-sectional view of a multicomponent
fiber having a solid eight segmented pie configuration.
Fig. 9 provides a schematic drawing illustrating a cross-sectional view of a tricompment
fiber having a solid islands-in-the-sea configuration. Component X surrounds a single
island of component Y and a plurality of islands of component Z.
DETAILED DESCRIPTION OF THE INVENTION
[0010] All percentages, ratios and proportions used herein are by weight percent of the
composition, unless otherwise specified. All average values are calculated "by weight"
of the composition or components thereof, unless otherwise expressly indicated. "Average
molecular weight", or "molecular weight" for polymers, unless otherwise indicated,
refers to number average molecular weight. Number average molecular weight, unless
otherwise specified, is determined by gel permeation chromotography.
[0011] The specification contains a detailed description of (1) materials for the fibers
of the present invention, (2) configuration of the fibers, (3) material properties
of the fiber, (4) processes, and (5) articles.
(1) Materials
First Component Material: Thermoplastic Polymers
[0012] Suitable melting temperatures of the thermoplastic polymers are from about 60°C to
about 300°C or, in some embodiments from about 80°C to about 250°C or from 100°C-215°C.
Thermoplastic polymers having a melting temperature (Tm) above 250°C may be used if
plasticizers or diluents or other polymers are used to lower the observed melting
temperature, such that the melting temperature of the composition of the thermoplastic
polymer-containing component is within the above ranges. It may be desired to use
a thermoplastic polymer having a glass transition (Tg) temperature of less than 0°C.
The thermoplastic polymer component has rheological characteristics suitable for melt
spinning. The molecular weight of the polymer should be sufficiently high to enable
entanglement between polymer molecules and yet low enough to be melt spinnable. For
melt spinning, suitable thermoplastic polymers can have molecular weights about 1,000,000
g/mol or below and, in some embodiments from about 5,000 g/mol to about 800,000 g/mol,
or from about 10,000 g/mol to about 700,000 g/mol or from about 20,000 g/mol to about
500,000 g/mol.
[0013] The thermoplastic polymers should be able to solidify fairly rapidly, preferably
under extensional flow, as typically encountered in known processes for staple fibers
(spin draw process), continuous filaments, or spunbond continuous filament processes,
and desirably can form a thermally stable fiber structure. "Thermally stable fiber
structure" as used herein is defined as not exhibiting significant melting or dimensional
change at 25°C and ambient atmospheric pressure over a period of 24 hours at 50% relative
humidity when the fibers are placed in the environment within five minutes of their
formation. Dimensional changes in measured fiber diameter greater than 25% difference,
using as a basis the corresponding, original fiber diameter measurement, would be
considered significant. If the original fiber is not round, the shortest diameter
should be used for the calculation. The shortest diameter should be used for the post-24
hour measurement also.
[0014] Suitable thermoplastic polymers include polyolefins or polyolefin copolymers such
as polyethylene or copolymers thereof, including low, high, linear low, or ultra low
density polyethylene or copolymer thereof, polypropylene or copolymers thereof, including
atactic polypropylene; polybutylene or copolymers thereof; polyamides or copolymers
thereof, such as Nylon 6, Nylon 11, Nylon 12, Nylon 46, Nylon 66; polyesters or copolymers
thereof, such as polyethylene terephalates; olefin carboxylic acid copolymers such
as ethylene/acrylic acid copolymer, ethylene/maleic acid copolymer, ethylene/methacrylic
acid copolymer, ethylene/vinyl acetate copolymers or combinations thereof; polyacrylates,
polymethacrylates, and their copolymers such as poly(methyl methacrylates). Other
nonlimiting examples of polymers include polycarbonates, polyvinyl acetates, poly(oxymethylene),
styrene copolymers, polyacrylates, polymethacrylates, poly(methyl methacrylates),
polystyrene/methyl methacrylate copolymers, polyetherimides, polysulfones, or combinations
thereof. In some embodiments, thermoplastic polymers include polypropylene, polyethylene,
polyamides, polyvinyl alcohol, ethylene vinyl alcohol, ethylene acrylic acid, polyolefin
carboxylic acid copolymers, polyesters, and combinations thereof.
[0015] Biodegradable thermoplastic polymers are also suitable for use herein. Biodegradable
materials are susceptible to being assimilated by microorganisms such as molds, fungi,
and bacteria when the biodegradable material is buried in the ground or otherwise
comes in contact with the microorganisms including contact under environmental conditions
conducive to the growth of the microorganisms. Suitable biodegradable polymers also
include those biodegradable materials which are environmentally degradable using aerobic
or anaerobic digestion procedures, or by virtue of being exposed to environmental
elements such as sunlight, rain, moisture, wind, temperature, and the like. The biodegradable
thermoplastic polymers can be used individually or as a combination of biodegradable
or non-biodegradable polymers.. Biodegradable polymers include polyesters containing
aliphatic components. Among the polyesters are ester polycondensates containing aliphatic
constituents and poly(hydroxycarboxylic) acid. The ester polycondensates include diacids/diol
aliphatic polyesters such as polybutylene succinate, polybutylene succinate co-adipate,
aliphatic/aromatic polyesters or copolyester such as terpolymers made of butylenes
diol, adipic acid and terephtalic acid. The poly(hydroxycarboxylic) acids include
lactic acid based homopolymers and copolymers, polyhydroxybutyrate (PHB), or other
polyhydroxyalkanoate homopolymers and copolymers. Such polyhydroxyalkanoates include
copolymers of PHB with higher chain length monomers, such as C6 - C12, and higher.
[0016] An example of a suitable commercially available poly lactic acid is NATUREWORKS from
Cargill Dow and LACEA from Mitsui Chemical. An example of a suitable commercially
available diacid/diol aliphatic polyester is the polybutylene succinate/adipate copolymers
sold as BIONOLLE 1000 and BIONOLLE 3000 from the Showa High Polymer Company, Ltd.
(Tokyo, Japan). An example of a suitable commercially available aliphatic/aromatic
copolyester is the poly(tetramethylene adipate-co-terephthalate) sold as EASTAR BIO
Copolyester from Eastman Chemical or ECOFLEX from BASF.
[0017] The selection of the polymer and amount of polymer will effect the softness, texture,
and properties of the final product as will be understood by those or ordinary skill
in the art. The thermoplastic polymer component can contain a single polymer species
or a blend of two or more non-starch thermoplastic polymers. Additionally, other materials
can be present in the thermoplastic polymer component. Typically, thermoplastic polymers
are present in an amount of from about 51% to 100%, preferably from about 60% to about
95%, more preferably from about 70% to about 90%, by total weight of the thermoplastic
polymer component.
Second Component Material: Thermoplastic Starch
[0018] The starch used in the present invention is thermoplastic, destructured starch. The
term "destructurized starch" is used to mean starch that is no longer in its naturally
occurring granular structure. The term "thermoplastic starch" or "TPS" is used to
mean starch with a plasticizer for improving its thermoplastic flow properties so
that it may be able to be spun into fibers.
[0019] Natural starch does not melt or flow like conventional thermoplastic polymers. Since
natural starch generally has a granular structure, it needs to be "destructurized",
or "destructured", before it can be melt processed and spun like a thermoplastic material.
Without intending to be bound by theory, the granular structure of starch is characterized
by granules comprising an structure of discrete amylopectin and amylose regions in
a starch granule. This granular structure is broken down during destructurization,
which can be followed by observing a volume expansion of the starch component in the
presence of the solvent or plasticizer. Starch undergoing destructuring in the presence
of the solvent or plasticizer also typically has an increase in viscosity versus non-destructured
starch with the solvent or plasticizer. The resulting destructurized starch can be
in gelatinized form or, upon drying and or annealing, in crystalline form, however
once broken down the natural granular structure-of starch will not, in general, return.
It is desirable that the starch be fully destructured such that no lumps impacting
the fiber spinning process are present. The destructuring agent used to destructure
the starch may remain with the starch during further processing, or may be transient,
in that it is removed such that it does not remain in the fiber spun with the starch.
[0020] Starch can be destructured in a variety of different ways. The starch can be destructurized
with a solvent. For example, starch can be destructurized by subjecting a mixture
of the starch and solvent to heat, which can be under pressurized conditions and shear,
to gelatinize the starch, leading to destructurization. Solvents can also act as plasticizers
and may be desirably retained in the composition to perform as a plasticizer during
later processing. A variety of plasticizing agents that can act as solvents to destructure
starch are described herein. These include the low molecular weight or monomeric plasticizers,
such as but not limited to hydroxyl-containing plasticizers, including but not limited
to the polyols, e.g. polyols such as mannitol, sorbitol, and glycerin. Water also
can act as a solvent for starch, and can be used to destructurize the starch by dissolving
it in water.
[0021] For starch to flow and be melt spinnable like a conventional thermoplastic polymer,
it should have plasticizer present. If the destructuring agent is removed, it is the
nature of the starch to in general remain destructured, however a plasticizer should
be added to or otherwise included in the starch component to impart thermoplastic
properties to the starch component in order to facilitate fiber spinning. Thus, the
plasticizer present during spinning may be the same one used to destructure the starch.
Alternately, especially when the destructuring agent is transient as described above,
a separate or additional plasticizer may be added to the starch. Such additional plasticizer
can be added prior to, during, or after the starch is destructured, as long as it
remains in the starch for the fiber spinning step.
[0022] Suitable naturally occurring starches can include, but are not limited to, corn starch,
potato starch, sweet potato starch, wheat starch, sago palm starch, tapioca starch,
rice starch, soybean starch, arrow root starch, bracken starch, lotus starch, cassava
starch, waxy maize starch, high amylose corn starch, and commercial amylose powder.
Blends of starch may also be used. Though all starches are useful herein, the present
invention is most commonly practiced with natural starches derived from agricultural
sources, which offer the advantages of being abundant in supply, easily replenishable
and inexpensive in price. Naturally occurring starches, particularly corn starch,
wheat starch, potato starch and waxy maize starch, are the preferred starch polymers
of choice due to their economy and availability.
[0023] Modified starch may also be used. Modified starch is defined as non-substituted,
or substituted, starch that has had its native molecular weight characteristics changed
(i.e. the molecular weight is changed but no other changes are necessarily made to
the starch). Molecular weight can be modified, preferably reduced, by any technique
numerous of which are well known in the art. These include, for example, chemical
modifications of starch by, for example, acid or alkali hydrolysis, acid reduction,
oxidative reduction, enzymatic reduction, physical/mechanical degradation (e.g., via
the thermomechanical energy input of the processing equipment), or combinations thereof.
The thermomechanical method and the oxidation method offer an additional advantage
when carried out
in situ. The exact chemical nature of the starch and molecular weight reduction method is
not critical as long as the average molecular weight is provided at the desired level
or range. Such techniques can also reduce molecular weight distribution.
[0024] Natural, unmodified starch generally has a very high average molecular weight and
a broad molecular weight distribution (e.g. natural corn starch has an average molecular
weight of up to about 60,000,000 grams/mole (g/mol)). It is desirable to reduce the
molecular weight of the starch for use in the present invention. Molecular weight
reduction can be obtained by any technique known in the art, including those discussed
above. Ranges of molecular weight for destructured starch or starch blends added to
the melt are from 10,000 g/mol to 5,000,000 g/mol, and preferably from 20,000 g/mol
to 3,000,000 g/mol.
[0025] Optionally, substituted starch can be used. Chemical modifications of starch to provide
substituted starch include, but are not limited to, etherification and esterification.
For example, methyl, ethyl, or propyl (or larger aliphatic groups) can be substituted
onto the starch using conventional etherification and esterification techniques as
well known in the art. Such substitution can be done when the starch is in natural,
granular form or after it has been destructured. Substitution can reduce the rate
of biodegradability of the starch, but can also reduce the time, temperature, shear,
and/or pressure conditions for destructurization. The degree of substitution of the
chemically substituted starch is typically, but not necessarily, from about 0.01 to
about 3.0, and can also be from about 0.01 to about 0.06.
[0026] Typically, the Thermoplastic starch comprises from about 51% to about 100%, preferably
from about 60% to about 95%, more preferably from about 70% to about 90% by weight
of the thermoplastic starch component. The ratio of the starch component to the thermoplastic
polymer will determine the percent of thermoplastic starch in the bicomponent fiber
component. The weight of starch in the composition includes starch and its naturally
occurring bound water content. The term "bound water" means the water found naturally
occurring in starch and before mixing of starch with other components to make the
composition of the present invention. The term "free water" means the water that is
added in making the composition of the present invention. A person of ordinary skill
in the art would recognize that once the components are mixed in a composition, water
can no longer be distinguished by its origin. Natural starch typically has a bound
water content of about 5% to about 16% by weight of starch.
Optional Second Component Material for Controlling the Rate of Starch Removal
[0027] An agent is present in the second component in combination with the starch that allows
control of the rate of starch release and thereby, the amount of starch released when
the multicomponent fiber is placed in a solvent such as water, for example. The agents
include:acid substituted vinyl polymers such as ethylene acrylic acid which is commercially
available as PRIMACOR from Dow Chemical Co. polyolefin carboxylic acid copolymers
such as ethylene acrylic acid copolymer, ethylene maleic acid copolymer, ethylene
methacrylic acid copolymer, ethylene acrylic acid copolymers, and combinations thereof;
a polyhydroxyetherester; a polyhydroxyetheramide such as the BLOX series of epoxy-based
thermoplastic resins from Dow Chemical Co.; aliphatic or aromatic carboxyamides having
a melting temperature above room temperature (25°C) and below the upper processing
temperature of thermoplastic starch of about 300°C and a minimum boiling point temperature
greater than 150°C; and aliphatic saturated or unsaturated C8-C22 carboxylic acids
such as caprylic, oleic, palmitic, stearic, linoleic, linolenic, ricinoleic, erucic
acids, or the corresponding fatty acid alcohols or amides of the fatty acids listed
above, in particular, mono-,di-, or triglycerides of the said fatty acids. Examples
of suitable aliphatic or aromatic carboxyamides are stearamide, benzamide, or propionamide,
for example. In particular embodiments of the invention, ethylene acrylic acid (BAA),
a polyhydroxyetherester (PHEE), a polyhydroxyetheramide (PHEA), or a combination thereof
is an agent present in the second component for controlling the rate of starch removal.
[0028] Such an agent is present in an amount of about 1% up to 50% by weight of the second
component and, in alternative embodiments, 2, 5, 10, 15, 20, 25, 30, 35, or 40% of
the weight of the second component. In general, a greater amount of agent slows the
rate of starch removal.
Plasticizer
[0029] One or more plasticizers can be used In the present invention to destructurize the
starch and enable the starch to flow, i.e. create a thermoplastic starch. As discussed
above, a plasticizer may be used as a destructuring agent for starch. That plasticizer
may remain in the destructured starch component to function as a plasticizer for the
thermoplastic starch, or may be removed and substituted with a different plasticizer
in the thermoplastic starch component. The plasticizers may also improve the flexibility
of the final products, which is believed to be due to the lovering of the glass transition
temperature of the composition.
[0030] A plasticizer or diluent for the thermoplastic polymer component may be present to
lower the polymer's melting temperature, modify flexibility of the final product,
or improve overall compatibility with the thermoplastic starch blend. Furthermore,
thermoplastic polymers with higher melting temperatures may be used if plasticizers
or diluents are present which suppress the melting temperature of the polymer.
[0031] In general, the plasticizers should be substantially compatible with the polymeric
components of the present invention with which they are intermixed. As used herein,
the term "substantially compatible" means when heated to a temperature above the softening
and/or the melting temperature of the composition, the plasticizer is capable of forming
a homogeneous mixture with polymer present in the component in which it is intermixed.
[0032] The plasticizers herein can include monomeric compounds and polymers. The polymeric
plasticizers will typically have a molecular weight less than 500,000g/mol. Polymeric
plasticizers can include block copolymers and random copolymers, including terpolymers
thereof. In certain embodiments, the plasticizer has a low molecular weight plasticizer,
for example a molecular weight of about 20,000 g/mol or less, or about 5,000 g/mol
or less, or about 1,000 g/mol or less. The plasticizers may be used alone or more
than one plasticizer may be used in any particular component of the present invention.
[0033] The plasticizer can be, for example, an organic compound having at least one hydroxyl
group, including polyols having two or more hydroxyls. Nonlimiting examples of useful
hydroxyl plasticizers include sugars such as glucose, sucrose, fructose, raffinose,
maltodextrose, galactose, xylose, maltose, lactose, mannose erythrose, and pentaerythritol;
sugar alcohols such as erythritol, xylitol, malitol, mannitol and sorbitol; polyols
such as glycerol (glycerin), ethylene glycol, propylene glycol, dipropylene glycol,
butylene glycol, hexane triol, and the like, and polymers thereof; and mixtures thereof.
Suitable plasticizers especially include glycerine, mannitol, and sorbitol.
[0034] Also useful herein are hydroxyl polymeric plasticizers such as poloxomers (polyoxyethylene
/polyoxypropylene block copolymers) and poloxamines (polyoxyethylene/polyoxypropylene
block copolymers of ethylene diamine). These copolymers are available as PLURONIC®
from BASF Corp., Parsippany, NJ. Suitable poloxamers and poloxamines are available
as SYNPERONIC® from ICI Chemicals, Wilmington, DE, or as TETRONIC® from BASF Corp.,
Parsippany, NJ. Also suitable for use are hydroxy-containing polymers such as polyvinyl
alcohol, ethylene vinyl alcohol, and copolymers and blends thereof.
[0035] Also suitable for use herein are hydrogen bond forming organic compounds, including
those which do not have hydroxyl group, including urea and urea derivatives; anhydrides
of sugar alcohols such as sorbitan; animal proteins such as gelatin; vegetable proteins
such as sunflower protein, soybean proteins, cotton seed proteins; and mixtures thereof.
Other suitable plasticizers are phthalate esters, dimethyl and diethylsuccinate and
related esters, glycerol triacetate, glycerol mono and diacetates, glycerol mono,
di, and tripropionates, butanoates, stearates, lactic acid esters, citric acid esters,
adipic acid esters, stearic acid esters, oleic acid esters, and other father acid
esters which are biodegradable. Aliphatic acids such as ethylene acrylic acid, ethylene
maleic acid, butadiene acrylic acid, butadiene maleic acid, propylene acrylic acid,
propylene maleic acid, and other hydrocarbon based acids are further examples of plasticizers.
[0036] When high processing temperature thermoplastic polymers are used, such as with polyamides
and polyesters, for example, the starch plasticizer must be carefully chosen so that
its vaporization temperature is above the processing temperature of the multicomponent
fiber. Plasticizers may be blended together to produce vaporization temperatures above
either one alone, commonly referred to as boiling point elevation. A good example
of a high boiling point starch plasticizer would be glycerol, which has a vaporization
temperature of 290°C.
[0037] The amount of plasticizer is dependent upon the molecular weight and amount of starch
and the affinity of the plasticizer for the starch or thermoplastic polymer. An amount
that effectively plasticizes the starch can be used. The plasticizer should sufficiently
plasticize the starch component so that it can be processed effectively to form fibers.
Generally, the amount of plasticizer increases with increasing molecular weight of
starch. Typically, the plasticizer can be present in an amount of from about 2% to
about 70%, and can also be from about 5% to about 55%, or from about 10% to about
50% of the component into which it is intermixed. A polymer incorporated into the
starch component that functions as a plasticizer for the starch shall be counted as
part of the plasticizer constituent of that component of the present invention. Plasticizer
is optional for the thermoplastic polymer components in the present invention and
can be used at any effective levels, including the ranges above, and amounts below
2% are also included.
Optional Materials
[0038] Optionally, other ingredients may be incorporated into the first or second component
compositions. These optional ingredients may be present in quantities of 49% or less,
or in alternative embodiments, from about 0.1% to about 30%, or from about 0.1% to
about 10% by weight of the component. The optional materials may be used to modify
the processability and/or to modify physical properties such as elasticity, tensile
strength and modulus of the final product. Other benefits include, but are not limited
to, stability including oxidative stability, brightness, color, flexibility, resiliency,
workability, processing aids, viscosity modifiers, and odor control. Optional ingredients
include nucleating agents, salts, slip agents, crystallization accelerators or retarders,
odor masking agents, cross-linking agents, emulsifiers, surfactants, cyclodextrins,
lubricants, other processing aids, optical brighteners, antioxidants, flame retardants,
dyes, pigments, fillers, proteins and their alkali salts, waxes, tackifying resins,
extenders, wet-strength resins, or mixtures thereof. Processing aids include magnesium
stearate or, particularly in the starch component, ethylene acrylic acid, commercially
available from Dow Chemical Co. as PRIMACOR.
(2) Configuration
[0039] The multiconstituent, multicomponent fibers of the present invention may be in several
different configurations as long as the second component is not encompassed by another
component or components or if encompassed by another component or components then
the second component encompasses a hollow core. Constituent, as used herein, is defined
as meaning the chemical species of matter or the material. Multiconstituent, as used
herein, is defined to mean a fiber or component thereof containing more than one chemical
species or material. The fibers will be multicomponent in configuration prior to removal
of a second component. Component, as used herein, is defined as a separate part of
the fiber that has a spatial relationship to another part of the fiber. The term multicomponent,
as used herein, is defined as a fiber having more than one separate part in spatial
relationship to one another. The term multicomponent includes bicomponent, which is
defined as a fiber having two separate parts in a spatial relationship to one another
at the exit from the extrusion equipment. The different components of multicomponent
fibers are arranged in substantially distinct regions across the cross-section of
the fiber and extend continuously along the length of the fiber.
[0040] The multicomponent fibers may have two, three, four or more components, as long as
the second component is not encompassed by another component or components or if encompassed
by another component or components then the second component encompasses a hollow
core. Accordingly, reference to a first component and a second component is not meant
to exclude other components, unless otherwise expressly indicated. The drawings provide
reference to a component, x, y, z, and w, for example. Components z and w may be third
and fourth components and may comprise another thermoplastic polymer or thermoplastic
blend, for example that provides enhanced physical properties beyond the combination
of a first and second component.
[0041] In one embodiment, the second component comprising the thermoplastic starch surrounds
the first component such as in, for example, a sheath-core configuration where the
sheath is the second component and the core is the first component.
[0042] In a further embodiment, the second component comprising the thermoplastic starch
surrounds the first component such as in, for example, an islands-in-a-sea configuration
where the islands are the first component and the sea is the second component.
[0043] Fig. 1A - Fig. 9 provide schematic drawings illustrating cross-sectional views of
various configurations of multicomponent fibers. A combination of one or more configurations
is also an aspect of the present invention. A configuration where the second component
is not encompassed by another component or components allows the second component
to be exposed to a solvent when the fiber is placed in the solvent. For example, in
Fig. 1A, Fig. 1B, Fig. 1I, Fig. 5A, Fig. 5B, Fig. 5C, the second component is y; in
Fig. 1E-Fig. 1H, Fig. 2A, Fig. 2B, Fig. 3, Fig. 4A-Fig. 4E, the second component is
either x or y; in Fig. 6, the second component is either x, y, or z; in Fig. 7, the
second component is z; in Fig. 8, the second component is wither x, y, z, or w; or
in Fig. 9, the second component is x. A configuration where the second component is
encompassed by another component or components and the second component encompasses
a hollow core also allows the second component to be exposed to a solvent when the
fiber is placed in the solvent since, in such a configuration, solvent may reach the
hollow core. For example, in Fig. 1C or Fig. 1D, the second component may be x or
y. When the second component is x in Fig. 1C or Fig. 1D, solvent has access to the
hollow core and starch may be removed from component x by the solvent.
[0044] The weight ratio of the second component to the first component can be from about
5:95 to about 95:5. In alternate embodiments, the ratio is from about 10:90 to about
65:35 or from about 15:85 to about 50:50.
[0045] The fibers of the present invention may also be splittable fibers. Splitting may
occur by a mechanical, thermodynamic, hydrodynamic or chemical means during or after
the removal of the second component or by fluid induced distortion.
[0046] A plurality of microfibrils may also result from the present invention. The microfibrils
are very fine fibers contained within a multi-constituent monocomponent or multicomponent
fiber. The plurality of polymer microfibrils have a cable-like morphological structure
and longitudinally extend within the fiber, which is along the fiber axis. The microfibrils
may be continuous or discontinuous. Microfibrils are formed in the present invention
as a result of the removal of the second component in a solvent. The thermoplastic
polymer is present in a sufficient amount to generate a co-continuous phase morphology
such that the polymer microfibrils may form. Typically, greater than 15%, preferably
from about 15% to about 90%, more preferably from about 25% to about 80%, and more
preferably from about 35% to about 70% of polymer is desired in the first component
for microfibril formation. A "co-continuous phase morphology" is found when the microfibrils
are substantially longer than the diameter of the fiber. Microfibrils are typically
from about 0.1 micrometers to about 10 micrometers in diameter while the fiber typically
has a diameter of from about (10 times the microfibril) 10 micrometers to about 50
micrometers. In addition to the amount of polymer, the molecular weight of the thermoplastic
polymer must be high enough to induce sufficient entanglement to form microfibrils.
In some embodiments, the molecular weight is from about 10,000 to less than 500,000
g/mol.
[0047] The microfibrils may be used in nonwoven articles that are desired to be extra soft
and/or have better barrier properties.
(3) Material Properties
[0048] The diameter of the fiber of the present invention is less than about 200 micrometers
(microns), and alternate embodiments can be less than about 100 microns, less than
about 50 microns, or less than 30 microns. In one embodiment hereof, the fibers have
a diameter of from about 5 microns to about 25 microns. Fiber diameter is controlled
by factors well known in the fiber spinning art including, for example, spinning speed
and mass through-put in addition to the process set forth herein.
[0049] The fibers produced in the present invention may be environmentally degradable depending
upon the amount of starch that is present, the polymer used, and the specific configuration
of the fiber. "Environmentally degradable" is defined being biodegradable, disintegratable,
dispersible, flushable, or compostable or a combination thereof. In the present invention,
the fibers, nonwoven webs, and articles may be environmentally degradable.
[0050] The fibers described herein are typically used to make disposable nonwoven articles.
The articles are commonly flushable. The term "flushable" as used herein refers to
materials which are capable of dissolving, dispersing, disintegrating, and/or decomposing
in a septic disposal system such as a toilet to provide clearance when flushed down
the toilet without clogging the toilet or any other sewage drainage pipe. The fibers
and resulting articles may also be aqueous responsive. The term aqueous responsive
as used herein means that when placed in water or flushed, an observable and measurable
change will result. Typical observations include noting that the article swells, pulls
apart, dissolves, or observing a general weakened structure.
[0051] The fibers of the present invention can have low brittleness and have high toughness,
for example a toughness of about 2MPa or greater. Toughness is defined as the area
under the stress-strain curve.
[0052] Extensibility or elongation is measured by elongation to break. Extensibility or
elongation is defined as being capable of elongating under an applied force, but not
necessarily recovering. Elongation to break is measured as the distance the fiber
can be stretched until failure. It has also been found that the fibers of the present
invention can be highly extensible.
[0053] The elongation to break of single fibers are tested according to ASTM standard D3822
except a strain rate of 200 %/min is used. Testing is performed on an MATS Synergie
400 tensile testing machine with a 10 N load cell and pneumatic grips. Tests are conducted
at a rate of 0.084 cm/s (2 inches/minute) on samples with a 2.5 cm (1-inch) gage length.
Samples are pulled to break. Peak stress and % elongation at break are recorded and
averaged for 10 specimens.
[0054] Nonwoven products produced from multicomponent fibers can also exhibit desirable
mechanical properties, particularly, strength, flexibility, softness, and absorbency.
Measures of strength include dry and/or wet tensile strength. Flexibility is related
to stiffness and can attribute to softness. Softness is generally described as a physiologically
perceived attribute which is related to both flexibility and texture. Absorbency relates
to the products' ability to take up fluids as well as the capacity to retain them.
(4) Processes
[0055] The first step in producing a multi-component fiber can be a compounding or mixing
step. In this compounding step, the raw materials are heated, typically under shear.
The shearing in the presence of heat can result in a homogeneous melt with proper
selection of the composition. The melt is then placed in an extruder where fibers
are formed. A collection of fibers is combined together using heat, pressure, chemical
binder, mechanical entanglement, and combinations thereof resulting in the formation
of a nonwoven web. The nonwoven is then assembled into an article.
Compounding
[0056] The objective of the compounding step is to produce a homogeneous melt composition
for each component of the fibers. Preferably, the melt composition is homogeneous,
meaning that a uniform distribution of ingredients in the melt is present. The resultant
melt composition(s) should be essentially free of water to spin fibers. Essentially
free is defined as not creating substantial problems, such as causing bubbles to form
which may ultimately break the fiber while spinning. The free water content of the
melt composition can be about 1% or less, about 0.5% or less, or about 0.15% of less.
The total water content includes the bound and free water. Preferably, the total water
content (including bound water and free water) is about 1% or less. To achieve this
low water content, the starch or polymers may need to be dried before processed and/or
a vacuum is applied during processing to remove any free water. The thermoplastic
starch, or other components hereof, can be dried at elevated temperatures, such as
about 60°C, before spinning. The drying temperature is determined by the chemical
nature of a component's constituents. Therefore, different compositions can use different
drying temperatures which can range from 20°C to 150°C and are, in general, below
the melting temperature of the polymer. Drying of the components may be in series
or as discrete steps combined with spinning., such as those known in the art.
[0057] In general, any method known in the art or suitable for the purposes hereof can be
used to combine the ingredients of the components of the present invention. Typically
such techniques will include heat, mixing, and pressure. The particular order or mixing,
temperatures, mixing speeds or time, and equipment can be varied, as will be understood
by those skilled in the art, however temperature should be controlled such that the
starch does not significantly degrade. The resulting melt should be homogeneous.
[0058] A suitable method of mixing for a starch and plasticizer blend is as follows:
- 1. The starch is destructured by addition of a plasticizer. The plasticizer, if solid
such as sorbitol or mannitol, can be added with starch (in powder form) into a twin-screw
extruder. Liquids such as glycerine, can be combined with the starch via volumetric
displacement pumps.
- 2. The starch is fully destructurized by application of heat and shear in the extruder.
The starch and plasticizer mixture is typically heated to 120-180°C over a period
of from about 10 seconds to about 15 minutes, until the starch gelatinizes.
- 3. A vacuum can applied to the melt in the extruder, typically at least once, to remove
free water. Vacuum can be applied, for example, approximately two-thirds of the way
down the extruder length, or at any other point desired by the operator.
- 4. Alternatively, multiple feed zones can be used for introducing multiple plasticizers
or blends of starch.
- 5. Alternatively, the starch can be premixed with a liquid plasticizer and pumped
into the extruder.
[0059] As will be appreciated by one skilled in the art of compounding, numerous variations
and alternate methods and conditions can be used for destructuring the starch and
formation of the starch melt including, without limitation, via feed port location
and screw extruder profile.
[0060] A suitable mixing device is a multiple mixing zone twin screw extruder with multiple
injection points. The multiple injection points can be used to add the destructurized
starch and the polymer. A twin screw batch mixer or a single screw extrusion system
can also be used. As long as sufficient mixing and heating occurs, the particular
equipment used is not critical.
[0061] An alternative method for compounding the materials comprises adding the plasticizer,
starch, and polymer to an extrusion system where they are mixed in progressively increasing
temperatures. For example, in a twin screw extruder with six heating zones, the first
three zones may be heated to 90°, 120°, and 130° C, and the last three zones will
be heated above the melting point of the polymer. This procedure results in minimal
thermal degradation of the starch and for the starch to be fully destructured before
intimate mixing with the thermoplastic materials.
[0062] An example of compounding destructured thermoplastic starch would be to use a Werner
&Pfleiderer 30 mm diameter 40:1 length to diameter ratio co-rotating twin-screw extruder
set at 250RPM with the first two heat zones set at 50°C and the remaining five heating
zones set 150°C. A vacuum is attached between the penultimate and last heat section
pulling a vacuum of 10 atm. Starch powder and plasticizer (e.g., sorbitol) are individually
fed into the feed throat at the base of the extruder, for example using mass-loss
feeders, at a combined rate of 30 lbs/hour (13.6 kg/hour) at a 60/40 weight ratio
of starch/plasticizer. Processing aids can be added along with the starch or plasticizer.
For example, magnesium stearate can be added at a level of 0 - 1 %, by weight, of
the thermoplastic starch component.
Spinning
[0063] The fibers of the present invention can be made by melt spinning. Melt spinning is
differentiated from other spinning, such as wet or dry spinning from solution, where
in such alternate methods a solvent is present in the melt and is eliminated by volatilizing
or diffusing it out of the extrudate.
[0064] Spinning temperatures for the melts can range from about 105°C to about 300°C, and
in some embodiments can be from about 130°C to about 230°C. The processing temperature
is determined by the chemical nature, molecular weights and concentration of each
component.
[0065] In general, high fiber spinning rates are desired for the present invention. Fiber
spinning speeds of about 10 meters/minute or greater can be used. In some embodiments
hereof, the fiber spinning speed is from about 100 to about 7,000 meters/minute, or
from about 300 to about 3,000 meters/minute, or from about 500 to about 2,000 meters/minute.
[0066] The fiber may be made by fiber spinning processes characterized by a high draw down
ratio. The draw down ratio is defined as the ratio of the fiber at its maximum diameter
(which is typically occurs immediately after exiting the capillary of the spinneret
in a conventional spinning process) to the final diameter of the formed fiber. The
fiber draw down ratio via either staple, spunbond, or meltblown process will typically
be 1.5 or greater , and can be about 5 or greater , about 10 or greater, or about
12 or greater.
[0067] Continuous fibers can be produced through, for example, spunbond methods or meltblowing
processes. Alternately, non-continuous (staple fibers) fibers can be produced according
to conventional staple fiber processes as are well known in the art. The various methods
of fiber manufacturing can also be combined to produce a combination technique, as
will be understood by those skilled in the art.
[0068] The fibers spun can be collected subsequent for formation using conventional godet
winding systems or through air drag attenuation devices. If the godet system is used,
the fibers can be further oriented through post extrusion drawing at temperatures
from about 50° to about 200° C. The drawn fibers may then be crimped and/or cut to
form non-continuous fibers (staple fibers) used in a carding, airlaid, or fluidlaid
process.
[0069] In the process of spinning fibers, particularly as the temperature is increased above
105°C, typically it is desirable for residual water levels to be 1%, by weight of
the fiber, or less, alternately 0.5% or less, or 0.15% or less to be present in the
various components.
[0070] Bicomponent melt spinning equipment is described in
US Patent 5,162,074 and is commercially available from, for example, Hills, Inc. located in Melbourne,
Florida USA. Suitable spinnert capillaries for use in spinning to make bicomponent
fibers include, for example, capillaries with a length-to diameter ration of about
4 and a diameter of about 0.35 mm, although other capillary dimensions can be used.
[0071] The process of spinning fibers and compounding of the components can be done in-line,
with compounding , drying and spinning as part of a continuous process and can be
the preferred process execution.
[0072] The residence time of each component in the spinline can have special significance
when a high melting temperatures thermoplastic polymer is chosen to be spun with destructured
starch. Spinning equipment can be designed to minimize the exposure of the destructured
starch component to high process temperature by minimizing the time and volume of
destructured starch exposed in the spinneret. For example, the polymer supply lines
to the spinneret can be sealed and separated until introduction into the bicomponent
pack. Furthermore, one skilled in the art of bicomponent fiber spinning will understand
that the at least two components can be introduced and processed in their separate
extruders at different temperatures until introduced into the spinneret.
[0073] For example, consider bicomponent spinning of an islands-in-a-sea fiber with a destructured
starch sea and polypropylene islands. The destructured starch component extruder profile
may be 80°C, 150°C and 150°C in the first three zones of a three heater zone extruder
with a starch composition similar to B3 of Example 1. The transfer lines and melt
pump heater temperatures will also be 150°C for the starch component. The polypropylene
component extruder temperature profile would be 180°C, 230°C and 230°C in the first
three zones of a three heater zone extruder. The transfer lines and melt pump are
heated to 230°C. In this case the spinneret temperature can range from 180°C to 230°C.
Exposure of Second Component to Second-Component-Removing Solvent
[0074] The second component can be removed by exposure of the multicomponent fiber to a
solvent in which the second component is removable. Most commonly, the solvent is
water, however, any solvent in which the second component is removed when the fiber
is placed in the solvent is contemplated. A further example of such a solvent is glycerine.
The fibers having the starch removed may be used in nonwoven articles that are desired
to be extra soft and/or have better barrier properties. Additionally, because starch
is an inexpensive material, the starch and polymer fibers with the starch removed
will be a more cost-effective fiber.
[0075] The starch component can also be removed by a combination technique where mechanical
or hydrodynamic methods can be used to remove the starch in isolation, in series or
in combination with a solvent
[0076] The rate of stanch removal can be measured by weight loss of the fibers versus time
exposed to solvent for the second component. The fibers are removed and dried in the
oven for 15 minutes at 115°C. The fibers are then removed from the oven and allowed
to cool in an open atmosphere at room temperature for 30 minutes before weighing.
Physical Manipulation of fibers
[0077] Fibers are handled during second component removal or after second component removal.
Non-limiting examples of handling include thermodynamic annealing, elongation, contraction
splitting, and fabric formation.
[0078] The present invention is a process of producing a melt spinnable fiber having a diameter
of less than 200 microns, the process comprising compounding a first component comprising
a thermoplastic polymer, compounding a second component comprising destructured starch,
spinning the first component with the second component to form a fiber having a diameter
of less than 200 microns, wherein the second component is not encompassed by another
component or components or if encompassed by another component or components thon
the second component encompasses a hollow core and contacting the fiber with a solvent
for the second component wherein the second component is removed from the fiber by
exposure to the solvent. The compounding of the second component further includes
an agent selected from the group consisting of an acid substituted vinyl polymer,
a polyolefin carboxylic acid copolymer, a polyhydroxyetherester, a polyhydroxyetheramide,
a C8-C22 aliphatic saturated or unsaturated carboxylic acid, an aliphatic carboxyamide,
and an aromatic carboxyamide, wherein the second component is removed from the fiber
by exposure to the solvent at a rate that is slower than that of a fiber lacking the
agent. A process that further comprises physically manipulating the fiber prior to
complete removal of then second component or after removal of the second component
are also aspects of the present invention.
(5) Articles
[0079] The fibers hereof may be used for any purposes for which fibers are conventionally
used. This includes, without limitation, incorporation into nonwoven substrates. The
fibers hereof may be converted to nonwovens by any suitable methods known in the art.
Continuous fibers can be formed into a web using industry standard spunbond or meltblown
type technologies while staple fibers can be formed into a web using industry standard
carding, airlaid, or wetlaid technologies. Typical bonding methods include: calendar
(pressure and heat), thru-air heat, mechanical entanglement, hydrodynamic entanglement,
needle punching, and chemical bonding and/or resin bonding. The calendar, thru-air
heat, and chemical bonding are the preferred bonding methods for the starch and polymer
multicomponent fibers. Thermally bondable fibers are required for the pressurized
heat and thru-air heat bonding methods.
[0080] The fibers of the present invention may also be bonded or combined with other synthetic
or natural fibers to make nonwoven articles. The synthetic or natural fibers may be
blended together in the forming process or used in discrete layers. Suitable synthetic
fibers include fibers made from polypropylene, polyethylene, polyester, polyacrylates,
and copolymers thereof and mixtures thereof. Natural fibers include cellulosic fibers
and derivatives thereof. Suitable cellulosic fibers include those derived from any
tree or vegetation, including hardwood fibers, softwood fibers, hemp, and cotton.
Also included are fibers made from processed natural cellulosic resources such as
rayon.
[0081] The fibers of the present invention may be used to make nonwovens, among other suitable
articles. Nonwoven articles are defined as articles that contains greater than 15%
of a plurality of fibers that are continuous or non-continuous and physically and/or
chemically attached to one another. The nonwoven may be combined with additional nonwovens
or films to produce a layered product used either by itself or as a component in a
complex combination of other materials, such as a baby diaper or feminine care pad.
Preferred articles are disposable, nonwoven articles. The resultant products may find
use in one of many different uses. Preferred articles of the present invention include
disposable nonwovens for hygiene and medical applications. Hygiene applications include
such items as wipes; diapers, particularly the top sheet or back sheet; and feminine
pads or products, particularly the top sheet.
Examples
[0082] The examples below further illustrate the present invention. The starches for use
in the examples below are STARDRI 1, STARDRI 100, ETHYLEX 2015, or ETHYLEX 2035, all
from Staley Chemical Company. The latter Staley materials are substituted starches.
The ethylene acrylic acid (EAA) is PRIMACORE 59801 from Dow Chemical. The polypropylene
(PP) resin is Basell PROFAX PH-835. The polyethylene (PE) is ASPUN 6811A from Dow
Chemical. The poly(L) lactic acid is BIOMER L9000 (Biomer). The polyethylene succinate
(PES) is BIONOLLE 1020 from Showa High Polymer (Tokyo, Japan). The polyester is F61HC
or 9663 from Eastman Chemical. The glycerine is from Dow Chemical Company, Kosher
Grade BU OPTIM* Glycerine 99.7%. The sorbitol is from Archer-Daniels-Midland Co. (ADM),
Crystalline NF/FCC 177440-2S. Other polymers having similar chemical compositions
that differ in molecular weight, molecular weight distribution, and/or comonomer or
defect level can also be used.
[0083] Example 1: Thermoplastic starch compositions (TPS'S) are prepared according to the following
formulations of Table 1. In Table 1, material 1 represents starch, material 2 represents
a plasticizer, and material 3 represents a non-starch thermoplastic polymer.
Table 1
|
|
|
|
|
Composition |
|
|
|
|
|
(by parts) |
|
Composition |
Material 1 |
Material 2 |
Material 3 |
Material 1 |
Material 2 |
Material 3 |
B1 |
Staley STARDRI 1 |
ADM sorbitol |
Dow PRIMACORE 5980I |
60 |
40 |
|
B2 |
Staley STARDRI 1 |
ADM sorbitol |
Dow PRIMACORE 5980I |
60 |
40 |
5 |
B3 |
Staley STARDRI 1 |
ADM sorbitol |
Dow PRIMACORE 5980I |
60 |
40 |
10 |
B4 |
Staley STARDRI 1 |
ADM sorbitol |
Dow PRIMACORE 5980I |
60 |
40 |
15· |
B5 |
Staley STARDRI 1 |
ADM sorbitol |
Dow PRIMACORE 5980I |
60 |
40 |
25 |
B6 |
Staley STARDRI 1 |
Dow Glycerine |
Dow PRIMACORE 5980I |
60 |
40 |
|
B7 |
Staley STARDRI 1 |
Dow Glycerine |
Dow PRIMACORE 5980I |
60 |
40 |
5 |
B8 |
Staley STARDRI 1 |
Dow Glycerine |
Dow PRIMACORE 5980I |
60 |
40 |
10 |
B9 |
Staley STARDRI 1 |
Dow Glycerine |
Dow PRIMACORE 5980I |
60 |
40 |
15 |
B10 |
Staley STARDRI 1 |
Dow Glycerine |
Dow PRIMACORE 5980I |
60 |
40 |
25 |
B11 |
Staley STARDRI 1 |
Dow Glycerine + ADM Sorbitol |
Dow PRIMACORE 5980I |
60 |
20 + 20 |
|
B12 |
Staley STARDRI 1 |
Dow Glycerine + ADM Sorbitol |
Dow PRIMACORE 5980I |
60 |
20 + 20 |
5 |
B13 |
Staley STARDRI 1 |
Dow Glycerine + ADM Sorbitol |
Dow PRIMACORE 5980I |
60 |
20 + 20 |
25 |
B14 |
Staley STARDRI 100 |
ADM sorbitol |
Dow PRIMACORE 5980I |
70 |
30 |
0 |
B15 |
Staley STARDRI 100 |
ADM sorbitol |
Dow PRIMACORE 5980I |
70 |
30 |
15 |
B16 |
Staley STARDRI 100 |
ADM sorbitol |
Dow PRIMACORE 5980I |
70 |
30 |
25 |
B17 |
Staley ETHYLEX 2015 |
ADM sorbitol |
Dow PRIMACORE 5980I |
60 |
40 |
0 |
B18 |
Staley ETHYLEX 2015 |
ADM sorbitol |
Dow PRIMACORE 5980I |
60 |
40 |
15 |
B19 |
Staley ETHYLEX 2035 |
ADM sorbitol |
Dow PRIMACORE 5980I |
60 |
40 |
0 |
B20 |
Staley ETHYLEX 2035 |
ADM sorbitol |
Dow PRIMACORE 5980I |
60 |
40 |
15 |
B21 |
Staley ETHYLEX 2015 + Staley ETHYLEX 2035 |
ADM sorbitol |
Dow PRIMACORE 5980I |
30 + 30 |
40 |
0 |
B22 |
Staley ETHYLEX 2015 + Staley ETHYLEX 2035 |
ADM sorbitol + Dow Glycerine |
Dow PRIMACORE + 5980I |
30 + 30 |
20 + 20 |
0 |
B23 |
Staley ETHYLEX 2015 + Staley ETHYLEX 2035 |
ADM sorbitol |
Dow PRIMACORE + 5980I |
30 + 30 |
40 |
15 |
B24 |
Staley ETHYLEX 2015 + Staley ETHYLEX 2035 |
ADM sorbitol + Dow Glycerine |
Dow PRIMACORE + 5980I |
30 + 30 |
20 + 20 |
15 |
B25 |
Staley ETHYLEX 2015 |
Dow Glycerine |
Dow PRIMACORE 5980I |
60 |
40 |
0 |
B26 |
Staley ETHYLEX 2035 |
Dow Glycerine |
Dow PRIMACORE 5980I |
60 |
40 |
0 |
B27 |
Staley ETHYLEX 2015 + Staley ETHYLEX 2035 |
Dow Glycerine |
Dow PRIMACORE 5980I |
60 |
40 |
0 |
B28 |
Staley ETHYLEX 2015 |
Dow Glycerine |
Dow PRIMACORE 5980I |
60 |
40 |
15 |
B29 |
Staley ETHYLEX 2035 |
Dow Glycerine |
Dow PRIMACORE 5980I |
60 |
40 |
15 |
[0084] The above materials can be prepared in a Wemer &Pfleiderer 30 mm diameter 40:1 length
to diameter ratio co-rotating twin-screw extruder (although 50mm Baker and Perkins
25:1 1 and 40:1 twin screw systems have been used) set at 250RPM with the first two
heat zones set at 50°C and the remaining zones to 150°C. A vacuum is attached between
the penultimate and last heat section pulling a vacuum of 10atm. The starch powder
and sorbitol are individually fed into the feed throat, preferably using mass-loss
feeders. Magnesium stearate is preferably added also at 0-1wt%. The glycerine is injected
after the first two heat zones via a heated liquid injection system. The total mass
through-put is typically set to 25lbs/hour, although rates ranging from 5-751bs/hour
have been used.
[0085] The compounded material is extruded onto an air quench conveyor table and pelletized.
Before spinning the TPS compositions, they are typically dried, if needed after compounding,
to moisture levels below 1wt% for the best spinning. The most preferred moisture content
is below 0.15wt%.
[0086] Example 2: The TPS composition B1 is melt spun with Basell PROFAX PH-835 using an hollow segmented
pie bicomponent pattern such as exemplified in Fig. 2B. The melt extrusion temperature
is 210°C. The ratio of components ranges from 10:90 to 50:50. The as-spun filaments
are placed in water and the TPS immediately dissolves in room temperature water.
[0087] Example 3: The TPS composition B1 is melt spun with Basell PROFAX PH-835 using an islands-in-a-sea
bicomponent pattern such as exemplified in Fig. 5A or Fig. 5B where the sea component
comprises the TPS. The melt extrusion temperature is 210°C. The ratio of components
ranges from 30:70 to 80:20. The as-spun filaments are placed in water and the TPS
immediately dissolves in room temperature water.
[0088] Example 4: The TPS composition By is melt spun with Basell PROFAX PH-835 using a solid sheath/core
such as exemplified in Fig. 1A or Fig. 1B with a TPS sheath. The melt extrusion temperature
is 210°C. The ratio of components ranges from 10:90 to 50:50. The as-spun filaments
are placed in water and the TPS immediately dissolves in room temperature water.
[0089] Example 5: The TPS composition B4 is melt spun with Basell PROFAX PH-835 using an hollow segmented
pie bicomponent pattern such as exemplified in Fig. 2B. The melt extrusion temperature
is 210°C. The ratio of components ranges from 10:90 to 50:50. The as-spun filaments
are placed in water and the TPS gradually dissolves in room temperature water over
about 15-60 minute time frame. The use of hot water makes it dissolve faster.
[0090] Example 6: The TPS composition B4 is melt spun with Basell PROFAX PH-835 using an islands-in-a-sea
bicomponent pattern such as exemplified in Fig. 5A or Fig. 5B where the sea component
comprises the TPS. The melt extrusion temperature is 210°C. The ratio of components
ranges from 30:70 to 80:20. The as-spun filaments are placed in water and the TPS
gradually dissolves in room temperature water over about 15-60 minute time frame.
The use of hot water makes it dissolve faster.
[0091] Example 7: The TPS composition B4 is melt spun with Basell PROFAX PH-835 using a solid sheath/core
such as exemplified in Fig. 1A or Fig. 1B with a TPS sheath. The melt extrusion temperature
is 210°C. The ratio of components ranges from 10:90 to 50:50. The as-spun filaments
are placed in water and the TPS gradually dissolves in room temperature water over
about 15-60 minute time frame. The use of hot water makes it dissolve faster.
[0092] Example 8: The TPS composition B5 is melt spun with Basell PROFAX PH-835 using an hollow segmented
pie bicomponent pattern such as exemplified in Fig. 2B. The melt extrusion temperature
is 210°C. The ratio of components ranges from 10:90 to 50:50. The as-spun filaments
are placed in water and are relatively stable in room temperature water over a period
of several hours. Over a period of several days they can dissolve in water. The use
of boiling water makes it dissolve faster.
[0093] Example 9: The TPS composition B5 is melt spun with Basell PROFAX PH-835 using an islands-in-a-sea
bicomponent pattern such as exemplified in Fig. 5A or Fig. 5B where the sea component
comprises the TPS. The melt extrusion temperature is 210°C. The ratio of components
ranges from 30:70 to 80:20. The as-spun filaments are placed in water and are relatively
stable in room temperature water over a period of several hours. Over a period of
several days they can dissolve in water. The use of boiling water makes it dissolve
faster.
[0094] Example 10: The TPS composition B5 is melt spun with Basell PROFAX PH-835 using a solid sheath/core
such as exemplified in Fig. 1A or Fig. 1B with a TPS sheath. The melt extrusion temperature
is 210°C. The ratio of components ranges from 10:90 to 50:50. The as-spun filaments
are placed in water and are relatively stable in room temperature water over a period
of several hours. Over a period of several days they can dissolve in water. The use
of boiling water makes it dissolve faster.
[0095] Examples 11-30 : Further bicomponent fibers can be produced according to Table 2.
Table 2
Example # |
|
TPS Composition |
Ratio Range |
Extrusion Temperature (°C) |
Bicomponent Configuration |
|
Polymer |
|
|
|
|
11 |
Basell PROFAX PH-835 |
B1-B22 |
70:30 to 10:90 |
190-220 |
Islands-in-a-Sea |
12 |
Basell PROFAX PH-835 |
B1-B22 |
70:30 to 10:90 |
190-220 |
Hollow Segmented Pie |
13 |
Basell PROFAX PH-835 |
B1-B22 |
70:30 to 10:90 |
190-220 |
Segmented Pie |
14 |
Basell PROFAX PH-835 |
B1-B22 |
90:10 to 10:90 |
190-220 |
Sheath/Core |
15 |
Dow ASPUN 6811A |
B1-B22 |
70:30 to 10:90 |
170-200 |
Islands-in-a-Sea |
16 |
Dow ASPUN 6811A |
B1-B22 |
70:30 to 10:90 |
170-200 |
Hollow Segmented Pie |
17 |
Dow ASPUN 6811A |
B1-B22 |
70:30 to 10:90 |
170-200 |
Segmented Pie |
18 |
Dow ASPUN 6811A |
B1-B22 |
90:10 to 10:90 |
170-200 |
Sheath/Core |
19 |
PLA |
B1-B22 |
70:30 to 10:90 |
190-220 |
Islands-in-a-Sea |
20 |
PLA |
B1-B22 |
70:30 to 10:90 |
190-220 |
Hollow Segmented Pie |
21 |
PLA |
B1-B22 |
70:30 to 10:90 |
190-220 |
Segmented Pie |
22 |
PLA |
B1-B22 |
90:10 to 10:90 |
190-220 |
Sheath/Core |
23 |
BIONOLLE 1020 |
B1-B22 |
70:30 to 10:90 |
170-200 |
Islands-in-a-Sea |
24 |
BIONOLLE 1020 |
B1-B22 |
70:30 to 10:90 |
170-200 |
Hollow Segmented Pie |
25 |
BIONOLLE 1020 |
B1-B22 |
70:30 to 10:90 |
170-200 |
Segmented Pie |
26 |
BIONOLLE 1020 |
B1-B22 |
90:10 to 10:90 |
170-200 |
Sheath/Core |
27 |
EASTAR BIO |
B1-B22 |
70:30 to 10:90 |
170-200 |
Islands-in-a-Sea |
28 |
EASTAR BIO |
B1-B22 |
70:30 to 10:90 |
170-200 |
Hollow Segmented Pie |
29 |
EASTAR BIO |
B1-B22 |
70:30 to 10:90 |
170-200 |
Segmented Pie |
30 |
EASTAR BIO |
B1-B22 |
90:10 to 10:90 |
170-200 |
Sheath/Core |
[0096] Examples 31-38 : Still further bicomponent fibers can be produced according to Table
Table 3
31 |
F61HCPET |
B6.B10:B25-B29 |
70:30 to 10:90 |
240-280 |
hlands-in-a-Sea |
32 |
F61HC PET |
B6-B10;B25-B29 |
70:30 to 10:90 |
240-280 |
Hollow Segmented Pie |
33 |
F61HC PBT |
B6-H10:B25-B29 |
70:30 to 10:90 |
240-280 |
Segmented Pie |
34 |
F61HC PBT |
B6-B10:B25- B29 |
90:10 to 10:90 |
240-280 |
Sheath/Core |
35 |
Polyamide 6 |
B6-B10:B25- B29 |
70:30 to 10:90 |
240-280 |
Islands-in-a-Sea |
36 |
Polyamide 6 |
B6-B10:B25- B29 |
70:30 to 10:90 |
240-280 |
Hollow Segmented Pie |
37 |
Polyamide 6 |
B6-B10:B25- B29 |
70:30 to 10:90 |
240-280 |
Segmented Pie |
38 |
Polyamide 6 |
Bb-B10:B25- B29 |
90:10 to 10:90 |
240-280 |
Sheath/Core |