Note: Descriptions are shown in the official language in which they were submitted.
BIODEGRADABLE SYNTHETIC POLYMER FIBRE
CROSS-REFERENCE TO A RELATED APPLICATION
[0001] The present application claims priority from U. S. provisional
patent application
serial number 63/146005 filed on February 5, 2021.
TECHNICAL FIELD
[0002] The present disclosure generally relates to the field of
biodegradable textiles,
yarns, fibers and methods for making same.
BACKGROUND
[0003] One commonly used material in textile items is a synthetic polymer
such as
polyester and nylon. The textile industry has produced and is producing an
alarming
amount of synthetic polymers, such as polyester textile, that is not
biodegradable. The
degradation of synthetic textile (polyesters, nylon, and the like) in
landfills or oceans can
take up to a hundred years or more. Furthermore, washing polyester containing
clothes in
washing machines releases micro-fibers into the water ecosystem. The micro-
plastics
pollute the oceans and can make their way up the food chain to fish that are
consumed by
the human population. There is therefore a need for improving the
biodegradability and
sustainability of synthetic textiles such as polyester and nylon.
SUMMARY
[0004] In one aspect, there is provided a synthetic polymer fibre
including: an
amorphous phase of at least 10 % of the crystallinity ratio, and 0.1 to 5.0
wt. % of a
biodegradation-inducing additive with respect to the total weight of the
synthetic polymer
fibre, the biodegradation-inducing additive being incorporated in the
amorphous phase
such that the biodegradation-inducing additive is physically and/or chemically
accessible
for a biodegradation initiation to form nuclei of biodegradation within the
amorphous
phase.
[0005] In one embodiment, the synthetic polymer fibre is a polyester fibre
or a
polyamide fibre.
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Date Recue/Date Received 2023-04-03
[0006] In one embodiment, the biodegradation-inducing additive is
dispersed in the
amorphous phase.
[0007] In one embodiment, the synthetic polymer fiber is made of a polymer
is
selected from poly(butylene succinate) (PBS), poly(butylene succinate)-co-
(butylene
adipate) (PBSA), poly(c-caprolactone) (PCL), poly(ethylene succinate) (PES),
poly(1-lactic
acid) (PLA), poly(3-hydroxybutyrate) and poly(3-hydoxybutyrate-co-3-
hydroxyvalterate)
(PHB/PHBV), poly(ethylene terephthalate) (PET), poly(butylene terephthalate)
(PBT),
poly(butylene adipate-co-terephthalate (PBAT), poly(butylene succinate-co-
terephthalate)
(PBST), poly(butylene succinate/terephthalate/isophthalate)-co-(lactate)
(PBSTIL), and
combinations thereof.
[0008] In one embodiment, the biodegradation-inducing additive is selected
from
polysaccharide, polylactic acid, polycaprolactone, polybutylene succinate,
polybutylene
terephthalate-coadipate, furanone, glutaric acids, carboxylic acids, or
EcoPureTM G2
additive.
[0009] In one embodiment, the biodegradation-inducing additive is a starch-
based
polymer.
[0010] In one embodiment, the biodegradation-inducing additive is present
in a
concentration of between 0.5 to 3.0 wt % with respect to the total weight of
the synthetic
polymer fibre.
[0011] In one embodiment, the synthetic polymer fibre further comprises a
carrier
polymer.
[0012] In one embodiment, the carrier polymer is selected from wool, flax,
cotton,
hemp, linen, cellulose, rayon, nylon, and/or silk.
[0013] In one embodiment, a weight ratio of the synthetic polymer fibre to
the carrier
polymer is between 1:10 to 10:1.
[0014] In one embodiment, the synthetic polymer fibre further includes a
flame
retardant additive.
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Date Recue/Date Received 2022-02-07
[0015] In
one embodiment, the biodegradation-inducing additive is incorporated in the
amorphous phase by physisorption, absorption or adsorption and does not form
any
intramolecular chemical bonds with the synthetic polymer fibre.
[0016] In
one aspect, there is provided a system for detecting the presence of a
biodegradable-inducing additive in a synthetic polymer fibre, the system
including: the
synthetic polymer fibre of the present disclosure; and a
colorimetric agent for
changing a color of the synthetic polymer fibre, where a color change within a
given
spectrum range, indicates the presence or absence of the biodegradation-
inducing
additive in the synthetic polymer fibre.
[0017] In a
further aspect there is provided a method of fabricating a biodegradable
synthetic fibre, including: obtaining the biodegradable synthetic fibre having
an extruded
synthetic polymer body; swelling the extruded synthetic polymer body to obtain
a swelled
extruded synthetic polymer body having an increased surface porosity when
compared to
the extruded synthetic polymer body; and incorporating a biodegradation-
inducing additive
into the swelled extruded synthetic polymer body, wherein the biodegradation-
inducing
additive penetrates pores of the surface of the swelled extruded synthetic
polymer body.
[0018] In
one embodiment, incorporating the biodegradation-inducing additive is
performed in one of a jet dyeing step, a beam dyeing step, a pad application
step, or an
autoclave purification step.
[0019] In
one embodiment, incorporating the biodegradation-inducing additive into the
swelled extruded synthetic polymer body includes embedding the biodegradation-
inducing
additive in an amorphous phase of the swelled extruded synthetic polymer body.
[0020] In
one embodiment, incorporating the biodegradation-inducing additive
includes increasing a temperature of the extruded polyester body to a
temperature of from
100 to 150 C.
[0021] In
one embodiment, the biodegradable synthetic polymer is a biodegradable
polyester.
[0022] In
yet a further aspect, there is provided a method of detecting whether a
biodegradation-inducing additive is present in a amorphous phase of a
synthetic polymer
fibre, the method includes: contacting a colorimetric agent with the synthetic
polymer fibre;
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Date Recue/Date Received 2022-02-07
and observing a change of color in the synthetic polymer fibre, a color change
within a
given spectrum range indicating the presence or absence of the biodegradation-
inducing
additive in the amorphous phase.
[0023] In still a further aspect, there is provided a method of detecting
whether a
biodegradation-inducing additive is present in a amorphous phase of a
synthetic polymer
fibre, the method includes: contacting a colorimetric agent with the synthetic
polymer fibre;
heating the synthetic polymer fibre to a temperature of 100-150 C in an
aqueous phase;
observing a change of color in the aqueous phase, a color change within a
given spectrum
range indicating the presence or absence of the biodegradation-inducing
additive in the
amorphous phase.
[0024] Many further features and combinations thereof concerning the
present
improvements will appear to those skilled in the art following a reading of
the instant
disclosure.
DESCRIPTION OF THE DRAWINGS
[0025] Fig. 1 is a flow chart illustrating a method for fabricating a
biodegradable
polyester in accordance with the present disclosure.
[0026] Fig. 2 is a graph showing the biodegradation (in percentage) in
function of time
(days) of two controls (negative and positive) and two textile samples in
accordance with
the present disclosure.
[0027] Fig. 3 is a graph showing the biodegradation (in percentage) in
function of time
(days) of two textile samples in accordance with the present disclosure
compared with a
negative control.
[0028] Fig. 4 is a photograph showing textile fibers stained with a
colorimetric indicator
for determining the presence of the biodegradation-inducing additive.
DETAILED DESCRIPTION
[0029] The present disclosure concerns biodegradable synthetic polymers,
and
particularly polyesters and nylons suitable for the textile industry. A
synthetic polymer is a
man made polymer. Herein below, the present disclosure describes polyesters in
relation
to a method of manufacturing a biodegradable synthetic fiber. However, the
polyester can
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Date Recue/Date Received 2022-02-07
be replaced by any other synthetic polymer, for example nylon (Le. a
polyamide). For
simplicity, the present disclosure focuses primarily on polyester fibers,
though it extends
to other synthetic fibers.
[0030] The synthetic polymers of the present disclosure, such as
polyester, have an
amorphous phase in their crystalline structure. In some embodiments, the
synthetic
polymers are semi-crystalline and have an amorphous phase of at least 10 %, 15
%, 20
%, 25 %, or 30% of the crystalline ratio. In one example, the synthetic
polymer is polyester
as described below. The polyester can have an amorphous phase of at least 10
%, 15 %,
20 %, 25 %, or 30 % of the crystallinity ratio. The amorphous phase percentage
can vary
based on whether the polyester is a recycled polyester. Recycled polyester can
have an
amorphous phase of at least 35 % or at least 40 %.
[0031] A polyester is a polymer containing repeating ester moieties
separated by
monomers such as a hydrocarbon chain that is optionally branched, optionally
interrupted,
optionally substituted, saturated or unsaturated. The polyester can have a
molecular
weight of 10,000 Da, 15,000 Da or more. The biodegradable polyester can be an
aliphatic
polyester or an aromatic polyester. In some embodiments, aliphatic polyesters
may have
a better biodegradability than aromatic polyesters. Aliphatic polyesters
generally have
more hydrolysable ester bonds that are susceptible to hydrolysis (for example
with
enzymes such as depolymerases). In addition, aliphatic polyesters generally
have a more
flexible polymeric chain which facilitates degradation. However, biodegradable
polyesters
can also be an aliphatic-aromatic co-polyester. In one embodiment, the
polyester is
selected from poly(butylene succinate) (PBS), poly(butylene succinate)-co-
(butylene
adipate) (PBSA), poly(c-caprolactone) (PCL), poly(ethylene succinate) (PES),
poly(1-lactic
acid) (PLA), poly(3-hydroxybutyrate) and poly(3-hydoxybutyrate-co-3-
hydroxyvalterate)
(PHB/PHBV), poly(ethylene terephthalate) (PET), poly(butylene terephthalate)
(PBT),
poly(butylene adipate-co-terephthalate (PBAT), poly(butylene succinate-co-
terephthalate)
(PBST), poly(butylene succinatetterephthalate/isophthalate)-co-(lactate)
(PBSTIL), and
combinations thereof.
[0032] A textile according to the present disclosure is a type of material
composed of
a synthetic polymer such as polyester, that may be in the form of fibers,
filaments, yarns,
membranes or fabrics. The fibers, filaments, yarns, and fabrics may be in
knit, woven or
non-woven forms. The term "non-woven" may be defined as a textile structure
that was
Date Recue/Date Received 2022-02-07
manufactured using mechanical, chemical, thermal, solvent methods, or
combinations
thereof to bond and/or interlock fibers. Many natural or synthetic fibers can
be
manufactured into yarns and threads, these include for example wool, flax,
cotton, hemp,
linen, nylon, silk, and polyester. Cotton and polyester are among the most
common fibers
in the textile industry that are used to produce yarns. In some embodiments,
the textile
material of the present disclosure, with polyester, can include at least a
portion of recycled
natural and/or synthetic fibers, filaments, yarns, fabrics, and precursor
forms.
[0033] The term "polyester textile" as used herein refers to a textile
having at least
about 10 wt % of a polyester. In one embodiment, the polyester textile has at
least 15 wt
%, at least about 20 wt %, at least about 25 wt %, or at least about 30 wt %
of a polyester.
The polyester textile can optionally comprise a polyester in combination with
one or more
carrier polymers, such as a resin(s). The term "carrier polymer" as used
herein refers to
polymers that can be combined with polyester into the polyester textile. For a
successful
production of a textile material the carrier polymer should be compatible and
miscible with
the polyester. The carrier polymer and the quantity of that carrier polymer
can be selected
to improve a physical and/or chemical property of the polyester textile. In
one embodiment,
the carrier polymer can be a nylon, an olefin, a natural polymer, a
biodegradable polymer,
and/or a thermoplastic biodegradable polymer. For example the carrier polymer
can be
wool, flax, cotton, hemp, linen, cellulose, rayon, nylon, and/or silk. In one
embodiment, the
weight percent ratio between the polyester and the carrier polymer in the
textile material
is between about 1:10 to about 10:1, between about 1:5 to about 5:1, between
about 3:1
to about 3:1, between about 2:1 to between about 1:2, or is about 1:1.
[0034] Polyesters have desirable properties for the textile industry. For
example, they
may exhibit a resistance to certain weak acids and alkalies, to organic
solvents (which are
often used in cleaning and stain removal products), to bleach damage, to
sunlight, to
synthetic detergents, and other laundry aids. On the other hand, polyester
(untreated and
without additives) is not sustainable and lacks biodegradability. Combining
polyester with
one or more carrier polymers can further improve the properties of the
material and/or limit
the disadvantages. For example, polyester may commonly be combined with cotton
(e.g.,
at around a 1:1 ratio) to produce a textile for clothing items. A particular
application for
polyester-cotton blends or polycotton fabrics is for making moisture wicking,
wrinkle
resistant, tear resistant, soft, and light-weight apparel. Different
combinations of polyester
and carrier polymers can be used to achieve a specific softness of the textile
material,
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Date Recue/Date Received 2022-02-07
specific moisture-absorbing properties, durability and water resistance. In
particular
embodiments, the polyester textile can be free of saccharides to improve the
durability of
the textile. For example, the polyester can have less than 5 wt % of
saccharides, less than
3 wt % of saccharides, and less than 1 wt % of saccharides.
[0035] The polyester textile or other like synthetic textile of the
present disclosure have
a biodegradable additive, a.k.a., a biodegradation-inducing additive
incorporated in the
amorphous phase to render the polyester (or synthetic textile) biodegradable.
In some
embodiments, the biodegradation-inducing additive is dispersed in the
amorphous phase
of the polymer. The biodegradable additive may be embedded in the amorphous
phase of
the polyester and dispersed such that many nuclei of biodegradation can occur,
thereby
improving the rate of biodegradation of the polyester. Thus, for simplicity,
the term
"biodegradable additive" is used herein and refers to any additive that can
render a
polyester polymer biodegradable. The biodegradable additive can be a
biodegradable
polymer. Biodegradable polymers promote the biodegradation of polyester by
degrading
first thereby creating a porous structure which increases the surface area and
reduces the
structural stability of polyester thereby further promoting biodegradation.
Examples of
biodegradable polymers additives include but are not limited to
polysaccharides such as
starch-based polymers, polylactic acid, polycaprolactone, polybutylene
succinate,
polybutylene terephthalate-coadipate, furanone, glutaric acids, carboxylic
acids, or
EcoPureTM G2 additive. In one embodiment, the biodegradable additive of the
present
disclosure is a polysaccharide, such as a starch-based polymer.
[0036] The biodegradable additive of the present disclosure is present in
the polyester
textile (or synthetic textile) between 0.1 to 5.0 wt %, between 0.5 to 3.0 wt
%, between 0.5
and 2 wt % or between 1.0 to 2.0 wt % with respect to the total weight of the
textile. A
minimal concentration of 0.1 wt %, 0.5 wt % or 1.0 wt % is included to impart
on the
polyester textile a biodegradability. The concentration of the biodegradable
additive is
limited to a maximal concentration of 5.0 wt %, 3.0 wt % or 2.0 wt % to
maintain the
mechanical properties of the polyester textile.
[0037] In one embodiment, the polyester is degraded into small organic
molecules by
hydrolysis and/or oxidation that are metabolized by microorganisms such as
bacteria to
turn the polyester into carbon dioxide (CO2), methane (CH4), water (H20), and
metabolic
biomass. Thus, biodegradation can be mediated by organisms that break down and
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Date Recue/Date Received 2022-02-07
convert polyester into sustainable products. In biological systems, many
factors are at play
including but not limited to external mechanical forces, moisture level,
humidity,
temperature, solar radiation, enzyme activities and other biotic interactions,
which can all
influence the rate of the microbial biodegradation. More generally, the
environmental
conditions, which also include a multitude of variable factors, play a major
role in
determining the rate and efficiency of polyester biodegradation. A second
aspect that
influences the rate and efficiency of biodegradation is the composition of the
polyester
textile. For example, a combination of 50/50 polyester and cotton textile is
more
biodegradable than a majority polyester textile. In the context of the present
disclosure,
the terms "more biodegradable" or "improved biodegradability" and the like,
are
comparison terms used when the compositions and environmental conditions of
the two
textile being compared are similar. Indeed, since cotton degrades much faster
than
polyester the degradation time of a 50/50 polyester cotton textile cannot be
directly
compared to a 80/20 polyester cotton. Moreover, two identical textile
compositions
degrading in environments having different numbers of suitable microorganisms
will not
degrade at the same rate.
[0038] The
term "biodegradable" as used herein with respect to a polyester textile
material can be defined as biodegrading at least 90 % of the polyester
polymers contained
in the polyester textile in less than 4 years. In one embodiment, at least 90
% of the
polyester contained in the polyester textile degrades in less than 3 years. In
one
embodiment, the fibers, yarns, fabrics, and precursors of polyester textile
containing the
biodegradable additive achieve a biodegradability of at least 8% after 70 days
and follows
a biodegradation curve to achieve 90 % degradation after 4 years, preferably 3
years
according to the ASTM D5511 standard test method for determining anaerobic
biodegradation of plastic materials under high-solids anaerobic-digestion
conditions.
When studying the biodegradability of a textile, the molecular composition of
the
precursors, intermediates and final products can be measured using as gel
permeation
chromatography, or more preferably a gradient analysis of polymer blends. In
one
example, the biodegradability of the textile polyester is measured, defined,
or determined
by methods specified in standard test protocols ASTM D6691, ASTM D5210, and
ASTM
D5511, developed and published by the American Society for Testing and
Materials.
ASTM D6691 is the Standard Test Method for Determining Aerobic Biodegradation
of
Plastic Materials in the Marine Environment by a Defined Microbial Consortium
or Natural
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Date Recue/Date Received 2022-02-07
Sea Water Inoculum, ASTM D5210 is the Test Method for Determining the
Anaerobic
Biodegradation of Plastic Materials in the Presence of Municipal Sewage
Sludge, and
ASTM D5511 is the Standard Test Method for Determining Anaerobic
Biodegradation of
Plastic Materials Under High-Solids Anaerobic-Digestion Condition. However,
ASTM tests
are not the only way to define the biodegradability of a textile and other
suitable
measurements may be used to evaluate the biodegradability of the textiles
according to
the present disclosure. Other standard tests include but are not limited to
those by the
Organisation for Economic Co-operations and Development (OECD), or the
International
Organization for Standardization (ISO).
[0039] To produce the biodegradable polyester textile of the present
disclosure the
biodegradable additive has to be incorporated in the amorphous phase of the
polyester.
In one embodiment, the biodegradable additive is incorporated by absorption,
absorption,
dispersion and/or physisorption. In one embodiment, the incorporation of the
biodegradable additive does not involve any intramolecular chemical bonds
between the
biodegradable additive and the polyester (e.g. covalent bonds). The
incorporation is
performed as a post-processing step of polyester textile material formation.
In one
embodiment, a "post-processing step" in the context of textile production can
be defined
herein as a step performed after extrusion of a textile. In one embodiment, a
"post-
processing" step in the context of textile production may be further defined
herein as after
the production of a fiber, filament, yarn, membrane and/or fabric from a
masterbatch. In
one embodiment, the masterbatch is free of biodegradable additives. In one
example, the
method can specifically exclude any step of adding a biodegradable additive
during the
masterbatch or extrusion step.
[0040] Referring to Fig. 1, a method for fabricating a biodegradable
polyester in
accordance with the present disclosure is generally shown at 10. According to
12, a
membrane, a strand, a filament, and/or fibers is (are) obtained, with the
membrane, strand,
filament, and/or fibers having an extruded polyester body. The polyester fiber
can be
subjected to a melt-spinning and extrusion process where the polyester is
heated and
becomes a molten polymer. The molten polymer is then extruded through a
spinneret in
continuous strands or filaments. To produce a mix textile of carrier polymer
(for example
cotton) and polyester, the extruded product can be blended with polyester and
carrier
polymer fibers together, and spinning the resulting textile blend. The textile
blends of the
present disclosure can have properties such as wrinkle, tear, and stain
resistance,
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Date Recue/Date Received 2022-02-07
reduced shrinking, long lasting durability, light weight, and moisture-wicking
capabilities.
In one embodiment, more than one carrier polymer can be included to produce
the textile
material (for example cotton and rayon). Therefore, the resulting textile may
be a tri-blend
yarn made of polyester, cotton, and rayon. This textile has mechanical
properties such as
improved softness and moisture-absorbing properties. The present method
advantageously allows flexibility in the choice of carrier polymers with
polyester and further
flexibility in the concentration of those carrier polymers as the
biodegradable additive is
added after the textile material is formed and therefore does not create any
limitations on
the composition of the polyester textile blends.
[0041] According to 14, swelling the extruded polyester body to obtain a
swelled
extruded polyester body having an increased surface porosity when compared to
the
extruded polyester body. In the context of the present disclosure "swell" or
"swelling" is
defined as opening or creating porous structures in a polymer textile. The
swelling can be
induced by increasing the temperature and/or the pressure. The swelling may be
performed by heating to a temperature of from 100 to 150 C, from 110 to 145
C, or from
120 to 140 C.
[0042] According to 16, the step of incorporating the biodegradable
additive in the
polyester is performed while the polyester is swelled. The porous structures,
or pores, are
exploited to incorporate the biodegradable additives and optionally other
components to
render the textile biodegradable. Any processing step that swells the polymer
can be used
as the step to incorporate the biodegradable additive. In one embodiment, the
biodegradable additive is incorporated in the polyester during a jet dyeing
step, a pad
application step, a beam dyeing step or the autoclave purification step. In
one
embodiment the biodegradable additive is incorporated with the paint, thereby
rendering
the present highly efficient as most textiles require a painting step anyway.
In some
embodiments, the biodegradable additive is incorporated without paint. This
can still be
done by performing a jet dyeing step, a beam dyeing step or a pad application
step while
not providing any paint but providing the biodegradable additive. When the
polyester is
swelled, the increased porosity promotes the incorporation of the
biodegradable additive
into the polymeric amorphous phase. This can be due to an increase in sites of
entry into
the polymeric amorphous phase. The biodegradable additive can be provided in
solution
or in suspension and dispersed into the amorphous phase of the swelled
polyester by
contacting the suspension or the solution with the swelled polyester.
Date Recue/Date Received 2022-02-07
[0043] The present method of making a textile biodegradable is more cost
effective
and efficient compared to prior art methods where the biodegradable additives
are added
at the masterbatch or extrusion step (e.g. when the polymer textile is in the
molten state).
Indeed, in one embodiment, the present method achieves a 10 %, preferably 20 %
cost
reduction when compared to a prior art method, particularly a prior art method
where the
biodegradable additive is added before extrusion. If the biodegradable
additive is added
at the masterbatch or extrusion step according to the prior art, the
biodegradable additive
may be encapsulated by the polyester. In contrast, the biodegradable additive
added
during the swelling as described herein incorporates into the amorphous phase
of the
polyester. Accordingly, a microorganism may not access the biodegradable
additive when
it is encapsulated in the polyester and may degrade the polyester slower than
when the
biodegradable additive is accessible to the microorganism and dispersed in the
amorphous phase of the polymer.
[0044] As a result from the method 10, there is produced a biodegradable
polyester
comprising: an extruded polyester body having surface porosity, and a
coating(s) on a
surface of the extruded polyester body, the coating(s) penetrating pores of
the surface,
the coating being a biodegradation-inducing additive. The biodegradable
polyester may
be a membrane, a strand, a filament, fibers, and may be part of a polyester
textile.
[0045] There is provided a method of detecting the presence of the
biodegradable
additive in a polyester textile with a calorimetric agent such as iodine. The
detection
method is a calorimetric assay in which a change in the color (a.k.a., colour)
of the
calorimetric agent indicates the presence of the biodegradable additive, such
as a change
of color within a given spectrum. Conversely, the absence of color change, or
a change of
color in the wrong spectrum of colors, indicates the absence of the
biodegradable additive.
To determine whether the biodegradable additive is incorporated in the
amorphous phase
of the synthetic polymer (e.g. polyester), a textile, fibers, filaments,
yarns, membranes or
fabrics, are contacted with the calorimetric agent and the color change of the
textile or the
like can be observed. In some embodiments, the color can be analyzed by naked
eye
observation, microscopic observation or by spectrophotometry (with for example
a
wavelength around 615 nm to identify the presence of blue iodine). In one
embodiment,
the polyester textile is contacted with the calorimetric agent (such as
iodine) and heated
in an aqueous phase to a temperature of from 100 to 150 C. The color change
or absence
of color change can thus be observed in the aqueous phase. If the
biodegradable additive
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Date Recue/Date Received 2022-02-07
was incorporated in the amorphous phase of the polyester it can be released
into the
aqueous phase and can react with the colorimetric agent to induce the change
of color.
[0046] Moreover, the colorimetric assay can help differentiate between a
polyester
having the biodegradable additive encapsulated therein (prior art) or
incorporated in the
amorphous phase of the polyester as described above. In one non-limitative
example, the
biodegradable additive is a polysaccharide such as a starch-based polymer.
Iodine may
be provided in solution with potassium (i.e. a solution of potassium iodide).
Other iodine
solutions are contemplated by the present disclosure. The potassium iodine
solution
typically has an orange-brown color. When the iodine comes in contact with the
polysaccharide (for example starch), the iodine will change color to become
dark blue, for
example. When the biodegradable additive is encapsulated in the polyester, the
iodine
cannot or may have limited access to biodegradable additive. This is also the
case even
when the polyester is heated to a temperature of from 100 to 150 C and
exposed to an
aqueous phase containing the colorimetric agent. The colorimetric assay can
therefore be
used to differentiate between a biodegradable additive that is encapsulated in
the
polyester versus a biodegradable additive that is incorporated or dispersed in
the
amorphous phase of the polyester. Indeed, when the biodegradable additive is
encapsulated there will be no color change or a very faint color change
compared to when
the biodegradable additive is dispersed in the amorphous phase of the
polyester.
[0047] A further additive may optionally be added to the synthetic
polymer, for
example an agent that promotes the microbial degradation of polyester (e.g.
recruiting
microorganisms or facilitating enzymatic reactions), and/or that promotes the
chemical
degradation of polyester (e.g. thermal oxidation, photo-oxidation, or
hydrolysis). To be
absorbed and metabolized by microorganisms the polyester has to be broken down
into
smaller organic molecules (oligomers, dimers, and/or monomers). In one
example,
reactions that break down the polyester include hydrolysis and oxidation. The
further
additive can be provided to promote, facilitate, or enhance microbial
degradation which
can be by direct or indirect attack on the polyester. In one embodiment, the
microbial
enzymes involved in polyester biodegradation include but are not limited to
lipase,
proteinase K, pronase, hydrogenase and the like. In one embodiment, the
further additive
can be a transition metal, calcium carbonate, a chemo attractant/chemo taxi
agent, and/or
an acid. The further additive can be a composition of elements that may not
impart
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Date Recue/Date Received 2022-02-07
biodegradability on their own but combine to achieve the effect of promoting
biodegradability.
[0048] The biodegradable polyester textile of the present disclosure can
be used to
produce any type of textile material. For example, the textile material can be
used in the
manufacture of knit fabrics, woven fabrics, nonwoven fabrics, apparel,
upholstery,
carpeting, bedding such as sheets or pillowcases, and industrial use fabrics
for agriculture
or construction. Further examples of apparel include: shirts, pants, bras,
panties, hats,
undergarments, coats, skirts, dresses, tights, stretch pants, scarves,
outerwear, suits,
underwear, swimsuits, active-wears, belts, ponchos, trousers, shorts,
footwear, fleece,
tees, bottoms, socks, bag, handkerchiefs, scarves, gloves, bags, backpacks,
and
handbags. In some embodiments, a flame retardant additive can be added to the
synthetic
polymer textile of the present disclosure to obtain a textile that has flame
resistance. The
flame retardant additive can for example be a phosphorus based flame
retardant.
EXAMPLE 1: BIODEGRADATION ASSAY
[0049] An ASTM D5511 standard test for determining anaerobic
biodegradation of
plastic materials under high-solids anaerobic-digestion conditions was
performed with two
polyester textile materials (sample #2 and sample #3) produced according to
the present
disclosure using a polysaccharide additive. A 100% polyester textile material
was used as
the negative control and inculum was used as the positive control. Table 1
below
summarizes the results after 148 days. Figures 2 and 3 shows the
biodegradation curve
of percent of biodegradation in function of time. The biodegradation curves
observed in
Figures 2 and 3 can be extrapolated to a 90 % degradation in 3-4 years.
Table 1: Summary of the results at 148 days ASTM D5511
13
Date Recue/Date Received 2022-02-07
m
InoulLim Negative VIPositive
Sample #2 Sample 43 '
Cumulative Gas
Volume (mL) 1286.4 1250.9 10217.1 2788.7,
3188.2
Percent CHI (LS:',i , 38.5 33.0 38.4 45.1
45.4
Volume CH4(rnL) 495.7 413.4 3919.0 1258.2
1448.9
Mass CH.i(g) _ 0.35 0.30 2.80 0.90,
1.03
Percent CC): M) 41.6 40.4 43.2 39.8
39.6
_
Volume CO2014 535.7 505.0 4414.9 1111.2
1263.9
Mass CO2(g) 1.05 0.99 8.67 2.18,
2.48
Sample Mass (9) _ 10 10 10 9.5
9.5
Theoretical
Sample Mass (g) 0.0 8.6 4.2, 5.9,
5.9
Biodegraded
N,,lass (ci) 0.55 0.49 4.46 1.27
1.45
Percent Biode-
graded (5,) -0.7 92.7 12.1_
15.2
EXAMPLE 2: DETECTION OF THE BIODEGRADATION AGENT
[0050] Polyester fibers were produced according to the present disclosure
with a
polysaccharide as the biodegradation additive. The polysaccharides include but
are not
limited to starch-based polymers. A portion of the fibers were exposed to
iodine which
changed color to dark blue indicating the presence of the polysaccharide (such
as starch)
embedded in the amorphous phase of the polyester fibers (Figure 4).
14
Date Recue/Date Received 2022-02-07
