U.S. patent application number 17/706644 was filed with the patent office on 2022-07-21 for liquid composition comprising biological entities and uses thereof.
The applicant listed for this patent is CARBIOS. Invention is credited to MEDIHA DALIBEY, ELODIE GUEMARD.
Application Number | 20220227957 17/706644 |
Document ID | / |
Family ID | |
Filed Date | 2022-07-21 |
United States Patent
Application |
20220227957 |
Kind Code |
A1 |
GUEMARD; ELODIE ; et
al. |
July 21, 2022 |
LIQUID COMPOSITION COMPRISING BIOLOGICAL ENTITIES AND USES
THEREOF
Abstract
The present invention relates to a new liquid composition
comprising biological entities having a polymer-degrading activity,
a carrier and a solvent that may be advantageously used for the
manufacture of a biodegradable plastic product.
Inventors: |
GUEMARD; ELODIE; (CHAMALI
RES, FR) ; DALIBEY; MEDIHA; (CLERMONT-FERRAND,
FR) |
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Applicant: |
Name |
City |
State |
Country |
Type |
CARBIOS |
SAINT-BEAUZIRE |
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FR |
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Appl. No.: |
17/706644 |
Filed: |
March 29, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16642390 |
Feb 27, 2020 |
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PCT/EP2018/073447 |
Aug 31, 2018 |
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17706644 |
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International
Class: |
C08J 11/10 20060101
C08J011/10; C08J 3/205 20060101 C08J003/205; C08J 3/22 20060101
C08J003/22 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 31, 2017 |
EP |
17306117.7 |
Claims
1. A liquid composition suitable to be incorporated in a partially
or totally molten polymer, comprising biological entities having a
polymer-degrading activity, a carrier and water, wherein: i) the
carrier is a polysaccharide selected from starch derivatives,
natural gums, marine extracts, microbial polysaccharides and animal
polysaccharides, and ii) the composition comprises, based on the
total weight of the composition: from 0.01% to 35% by weight of
biological entities, from 15% to 95% by weight of water, and from
3% to 80% by weight of carrier.
2. The composition of claim 1, wherein the liquid composition is in
a liquid form at least at ambient temperature.
3. The composition of claim 1, comprising based on the total weight
of the composition: from 0.3% to 30% by weight of biological
entities, from 19% to 85% by weight of the water, and from 4% to
80% by weight of carrier.
4. The composition of claim 1, comprising based on the total weight
of the composition: from 0.3% to 30% by weight of biological
entities, from 19% to 60% by weight of the water, and from 15% to
70% by weight of carrier.
5. The composition of claim 1, wherein the composition comprises
more than 20% by weight of water, based on the total weight of the
composition.
6. The composition of claim 1, wherein the composition comprises
more than 30%, and less than 80%, by weight of water, based on the
total weight of the composition.
7. The composition of claim 1, wherein the biological entities are
selected from enzymes having a polymer-degrading activity.
8. The composition of claim 1, wherein the biological entities are
selected from enzymes having a polyester-degrading activity.
9. The composition of claim 1, wherein the biological entities are
selected from enzymes having a PLA-degrading activity.
10. The composition of claim 1, wherein the composition comprises
less than 70% by weight of carrier.
11. The composition of claim 1, wherein the carrier is a natural
gum selected from arabic gum, guar gum, tragacanth gum or karaya
gum.
12. The composition of claim 1, comprising based on the total
weight of the composition: from 0.01% to 35% of biological
entities, from 30% to 75% of water, and from 10% to 69.99% of a
carrier.
13. The composition of claim 1, comprising based on the total
weight of the composition: from 0.01% to 35% of PLA-degrading
enzymes, from 30% to 75% of water, and from 10% to 69.99% of arabic
gum.
14. The composition of claim 1, comprising based on the total
weight of the composition about 50% of water, from 0.01% to 35% of
PLA-degrading enzymes, and from 20% to 49.99% of arabic gum.
15. The composition of claim 1, wherein the carrier is a starch
derivative.
16. A plastic article comprising a polymer and the composition
according to claim 1, wherein the biological entities of the
composition are able to degrade said polymer of the plastic
article.
17. A process for preparing a plastic article comprising the steps
of: a) preparing a masterbatch comprising polymer-degrading
biological entities and a first polymer by: (i) heating said first
polymer; and (ii) introducing from 5% to 50% by weight of the
composition according to claim 1, based on the total weight of the
masterbatch, during heating of the first polymer; and b)
introducing the masterbatch in a polymer-based matrix during
production of the plastic article, wherein step a) is performed at
a temperature at which the first polymer is in a partially or
totally molten state, and step b) is performed at a temperature at
which both the first polymer and the polymer of the polymer-based
matrix are in a partially or totally molten state and wherein the
biological entities of the composition are able to degrade a
polymer of the polymer-based matrix.
18. The process of claim 17, wherein the first polymer is a polymer
having a melting temperature below 140.degree. C. and/or a glass
transition temperature below 70.degree. C. selected from a
polyester, starch, EVA or mixtures thereof.
19. The process of claim 17, wherein the first polymer is selected
from PCL, EVA, PBAT, PLA or mixtures thereof.
20. A process for the manufacture of a plastic article comprising a
step (a) of mixing between 0.01% and 10% by weight of the
composition according to claim 1, with a least one polymer, wherein
the biological entities of the composition are able to degrade said
polymer and a step (b) of shaping said mixture of step (a) in a
plastic article.
21. The process of claim 20, wherein the step (a) of mixing is
performed at a temperature at which the polymer is in a partially
or totally molten state.
22. A process for preparing a masterbatch comprising: (i) extruding
a first polymer, wherein said first polymer has a melting
temperature below 140.degree. C.; and (ii) introducing the liquid
composition of claim 1 during extrusion of the first polymer.
23. The process for preparing a masterbatch of claim 22, wherein
the first polymer is selected from PCL, PBS, PBSA, PBAT, PLA and
EVA.
24. A process for the manufacture of a plastic article containing
biological entities comprising successively a step of introducing
the liquid composition according to claim 1 in a first polymer to
obtain a mixture, and a step of introducing said mixture in a
second polymer different from the first polymer, wherein the first
polymer has melting point below 140.degree. C. and the second
polymer has a melting point above 140.degree. C.
25. The composition of claim 1, comprising based on the total
weight of the composition: from 20% to 80% by weight of water, from
0.01% to 30% by weight of PLA-degrading enzymes, from 10% to 50% by
weight of arabic gum, from 0% to 5% by weight of other components
selected from proteins, salts, polyols.
26. The composition of claim 1, comprising based on the total
weight of the composition: from 40% to 60% by weight of water, from
0.01% to 30% by weight of PLA-degrading enzymes, from 15% to 40% by
weight of maltodextrin, from 0% to 5% of other components selected
from proteins, salts, polyols.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. Ser. No.
16/642,390, filed Feb. 27, 2020, which is the U.S. national stage
application of International Patent Application No.
PCT/EP2018/073447, filed Aug. 31, 2018.
FIELD OF THE INVENTION
[0002] The present invention relates to a novel liquid composition
comprising both biological entities able to degrade a polymer and a
carrier able to protect and stabilize such biological entities
during a heating process, such as extrusion. The invention also
relates to the use of such liquid composition for the manufacture
of biodegradable plastic articles, wherein the biological entities
are homogeneously dispersed in the plastic articles.
BACKGROUND OF THE INVENTION
[0003] Different biodegradable plastic compositions have been
developed in order to answer to plastic environmental issues and
the piling up of plastic articles in landfill sites and in natural
habitats, and to comply with restrictive legislation in particular
about short-lived products (such as bags, packaging including
trays, containers, bottles, agricultural films, etc.).
[0004] These plastic compositions generally contain polyester,
flours or starches derived from diverse cereals. Recently, a novel
solution has been proposed to control further the degradation of
plastic articles, by inclusion of biological entities capable of
degrading polyesters in the plastic composition used for
manufacturing the plastic articles (WO 2013/093355; WO 2016/198652;
WO 2016/198650; WO 2016/146540; WO 2016/062695). The resulting
plastic product contains biological entities, particularly enzymes,
dispersed in a polymer, and has an improved biodegradability as
compared to plastic articles deprived of such biological
entities.
[0005] However, the inclusion of biological entities in a partially
or totally molten polymer during the manufacture of plastic
articles may raise technical problems. Indeed, the composition of
biological entities may be hardly miscible into the polymer, the
biological entities may be non-homogenously dispersed into the
polymer and/or lose at least partially their degrading
activity.
SUMMARY OF THE INVENTION
[0006] By working on these problems, the inventors have developed a
liquid composition of biological entities that makes possible to
homogenously disperse such biological entities in a polymer in a
totally or partially molten state. The resulting plastic articles
show improved physical properties as compared to plastic products
manufactured with biological entities in solid form. Particularly,
the inventors have discovered that the presence of a specific
carrier in the composition containing the biological entities may
preserve the degrading-activity of the biological entities even
during and after a heat treatment. The inventors have thus
developed a liquid composition containing at least biological
entities having a polymer-degrading activity, a particular
stabilizing and protecting carrier and an aqueous solvent and they
have shown that such stabilized liquid composition leads to plastic
articles with an improved biodegradability as compared to plastic
products produced with liquid compositions of the prior art.
[0007] Interestingly, the inventors have further discovered that in
certain cases, the use of a two-steps process for the manufacture
of a plastic article containing biological entities preserves
further the degrading activity of the biological entities. More
particularly, the first step consists in the introduction of the
liquid composition containing biological entities in a first
polymer with a low melting point (below 140.degree. C.), followed
by the introduction of such mixture in a second polymer with a high
melting point (above 140.degree. C.).
[0008] The invention provides a new liquid composition comprising
biological entities and a carrier.
[0009] The composition of the invention is particularly useful for
the production of biodegradable plastic articles comprising
biological entities able to degrade at least one polymer of the
plastic article and with improved mechanical properties such as
Haze, surface roughness, elongation at break, tensile stress at
break, dynamic friction coefficient or Young modulus, and
biodegradability performance as compared to plastic articles
manufactured with biological entities in solid form. Particularly,
the use of such liquid composition allows to reduce the surface
roughness and eventually the thickness of the plastic article
without going through heavy and expensive grinding operations of a
solid composition (e.g.: in powder form). In addition, the
pulverulence of the constituents of such liquid composition is
reduced as compared to solid composition (e.g.: in powder form),
leading to lower risks of inhalation of particles during the
plastic article production process.
[0010] It is thus an object of the invention to provide a liquid
composition suitable to be incorporated in a partially or totally
molten polymer and comprising biological entities having a
polymer-degrading activity, a carrier and an aqueous solvent,
wherein
i) the carrier is a polysaccharide selected from starch
derivatives, natural gums, marine extracts, microbial
polysaccharides and animal polysaccharides, and ii) the composition
comprises, based on the total weight of the composition: [0011]
from 0.01% to 35% by weight of biological entities, [0012] from 15%
to 95% by weight of an aqueous solvent, and [0013] from 3% to 80%
by weight of a carrier.
[0014] Preferably, the composition of the invention comprises based
on the total weight of the composition: [0015] from 0.3% to 30% by
weight of biological entities, preferably selected from protease,
esterase, or lipase, [0016] from 19% to 60% by weight of an aqueous
solvent, preferably water, and [0017] from 15% to 70% by weight of
a carrier.
[0018] Alternatively, the composition of the invention comprises
based on the total weight of the composition: [0019] from 0.01% to
35% of biological entities, preferably selected from PLA-degrading
enzymes, [0020] from 30% to 75% of water, and [0021] from 10% to
69.99% of a carrier, preferably Arabic gum.
[0022] The liquid composition of the invention is particularly
useful for the manufacture of plastic compositions and plastic
articles. Advantageously, the biological entities of the
composition are able to degrade at least one polymer of the plastic
article. The biological entities are homogeneously dispersed in the
resulting plastic articles. Interestingly, said plastic articles
have great mechanical properties and degradability.
[0023] It is thus another object of the invention to provide a
process to manufacture a plastic article by use of the composition
of the invention, preferably by extrusion and a plastic article
made from such composition.
[0024] It is a further object of the invention to provide a process
for the manufacture of a plastic article containing biological
entities comprising successively a step of introducing the liquid
composition of the invention in a first polymer to obtain a
mixture, and a step of introducing said mixture in a second polymer
different from the first polymer, wherein the first polymer has a
melting point below 140.degree. C. and the second polymer has a
melting point above 140.degree. C.
[0025] The invention is also related to a method for increasing the
homogeneity of dispersion of polymer-degrading biological entities
in a biodegradable plastic article, said method comprising
introducing the liquid composition of the invention during the
process of manufacturing of the plastic article.
[0026] The invention also provides a method for increasing the
biodegradability of a plastic article comprising at least one
polymer, said method comprising introducing during the process of
production of the plastic article, the liquid composition of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0027] The present invention relates to novel liquid compositions
comprising stabilized biological entities that may be used for
manufacturing plastic articles wherein said biological entities are
homogeneously dispersed. The liquid compositions of the invention
comprise a carrier, selected from starch derivatives, natural gums,
marine extracts, microbial polysaccharides and animal
polysaccharides, which allows, solubilized within an aqueous
solvent, to protect and stabilize the biological entities during a
heating process, such as an extrusion process. The composition of
the present invention allows the manufacture of biodegradable
plastic articles, wherein the biological entities are homogeneously
distributed and have a degrading activity. These results are
compatible with the physical/mechanical properties and
degradability expected for single-use and short-lived plastic
articles.
Definitions
[0028] The present disclosure will be best understood by reference
to the following definitions.
[0029] Within the context of the invention, the term "plastic
article" refers to any item made from at least one polymer, such as
plastic sheet, film, tube, rod, profile, shape, massive block,
fiber, etc. Preferably, the plastic article is a manufactured
product, such as a rigid or flexible packaging, agricultural films,
bags and sacks, disposable items or the like. Preferably, the
plastic article comprises a mix of semi-crystalline and/or
amorphous polymers, or semi-crystalline polymers and additives. The
plastic articles may contain additional substances or additives,
such as plasticizers, mineral or organic fillers. According to the
invention, the plastic article may be selected from a plastic film,
a rigid plastic article or a non-woven fabric.
[0030] According to the invention, the term "plastic film" refers
to a flexible sheet of plastic (i.e., capable of being flexed
without breaking) with a thickness below 250 .mu.m. Thin film are
considered to have a thickness below 100 .mu.m, preferably below 50
.mu.m and are preferably produced by blown-film extrusion, whereas
thick film have a thickness above 100 .mu.m and are preferably
produced by cast film extrusion. Examples of plastic films include
agricultural films, plastic bags or sacks, films for flexible
packaging, food films, mailing films, liner films, multipack films,
industrial films, personal care films, nets, etc.
[0031] According to the invention, the term "rigidplastic article"
refers to a plastic article which is not a film. These articles are
preferably produced by calendering, injection-molding,
thermoforming, blow molding, or even by rotomolding and 3D
printing. Examples of rigid plastic articles are thin wall
packaging such as food and beverage packaging, boxes, trays,
containers, food service ware, electronics casings, cosmetic cases,
outdoor gardening items such as pots, rigid packaging, containers,
cards, cotton swabs, irrigation pipes, etc. Some rigid plastic
articles may be produced by thermoforming plastic sheets with a
thickness of 250 .mu.m or more, such plastic sheets being produced
by film casting or calendering. According to the invention the
rigid plastic article has a thickness below 5 mm, preferably below
3 mm.
[0032] As used herein, the terms "plastic composition" designates a
mixture of polymers and biological entities, and eventually
additional compounds (e.g., additives, filler, etc.) before any
shaping step or conditioning step to produce a plastic article. In
a particular embodiment of the invention the plastic composition is
a masterbatch under a solid form, before its introduction in a
polymer-based matrix.
[0033] A "polymer-based matrix" refers to a matrix comprising, as
the main ingredient, one or more polymer(s). The polymer-based
matrix comprises at least 51% by weight of polymer (s), based on
the total weight of the composition, preferably at least 60% or
70%. The polymer-based matrix may further comprise additional
compounds, such as additives. According to the invention, the
polymer-based matrix is deprived of any biological entities. A
"polyester-based matrix" refers to a matrix comprising, as the main
ingredient, one or more polyester(s).
[0034] As used herein, the term "masterbatch" designates a
concentrated mixture of selected ingredients (e.g., biological
entities, additives, etc.) and polymer that can be used for
introducing said ingredients into plastic articles or compositions
in order to impart desired properties thereto. Masterbatch
compositions allow the processor to introduce selected ingredients
economically during plastic manufacturing process. Advantageously,
the masterbatch is composed of a polymer wherein the selected
ingredients are incorporated in high concentration. Generally, the
masterbatch is dedicated to be mixed with polymer(s) or a
polymer-based matrix to produce a final plastic having a desired
amount of selected ingredients. The masterbatch may further
comprise mineral or organic fillers. According to the invention,
the masterbatch comprises at least 5% of a composition of
biological entities of the invention having a polymer-degrading
activity.
[0035] A "polymer" refers to a chemical compound or mixture of
compounds whose structure is constituted of multiple repeating
units linked by covalent chemical bonds. Within the context of the
invention, the term "polymer" includes natural or synthetic
polymers, comprising a single type of repeating unit (i.e.,
homopolymers) or different types of repeating units (i.e., block
copolymers and random copolymers). As an example, synthetic
polymers include polymers derived from petroleum oil or biobased
polymers, such as polyolefins, aliphatic or aromatic polyesters,
polyamides, polyurethanes and polyvinyl chloride. Natural polymers
include lignin and polysaccharides, such as cellulose,
hemi-cellulose, starch and derivatives thereof that may or may not
be plasticized.
[0036] "Synthetic polymers" refers to polymers derived from
petroleum oil or biobased polymers, and may be selected from the
group consisting to polyolefins, aliphatic or semi-aromatic
polyesters, polyamides, polyurethanes, or vinyl polymers and
derivatives thereof or blends/mixtures of these materials.
Preferred polyolefins for use in the present invention include,
without limitation, polyethylene (PE), polypropylene (PP),
polymethylpentene (PMP), polybutene-1 (PB-1), polyisobutylene
(PIB), ethylene propylene rubber (EPR), ethylene propylene diene
monomer rubber (EPDM), cyclic olefin copolymer (COC) and
derivatives or blends/mixtures thereof. Preferred aliphatic
polyesters for use in the invention include, without limitation,
polylactic acid (PLA), poly(L-lactic acid) (PLLA), poly(D-lactic
acid) (PDLA), poly(D,L-lactic acid) (PDLLA), PLA stereocomplex
(scPLA), polyglycolic acid (PGA), polyhydroxyalkanoate (PHA),
polycaprolactone (PCL), polybutylene succinate (PBS); and
semi-aromatic polyetsers are selected from polyethylene
terephthalate (PET), polytrimethylene terephthalate (PTT),
polybutylene terephthalate (PBT), polyethylene isosorbide
terephthalate (PEIT), polybutylene succinate adipate (PBSA),
polybutylene adipate terephthalate (PBAT), polyethylene furanoate
(PEF), poly(ethylene adipate) (PEA), polyethylene naphthalate
(PEN), and derivatives or blends/mixtures thereof. Preferred
polyamide polymers (also called nylon) for use in the invention
include without limitation, polyamide-6 or poly(.beta.-caprolactam)
or polycaproamide (PA6), polyamide-6,6 or poly(hexamethylene
adipamide) (PA6,6), poly(11-aminoundecanoamide) (PA11),
polydodecanolactam (PA12), poly(tetramethylene adipamide) (PA4,6),
poly(pentamethylene sebacamide) (PA5,10), poly(hexamethylene
azelaamide) (PA6,9), poly(hexamethylene sebacamide) (PA6,10),
poly(hexamethylene dodecanoamide) (PA6,12), poly(m-xylylene
adipamide) (PAMXD6), polyhexamethylene
adipamide/polyhexamethyleneterephtalamide copolymer (PA66/6T),
polyhexamethylene adipamide/polyhexamethyleneisophtalamide
copolymer (PA66/6I) and derivatives or blends/mixtures thereof.
Preferred vinyl polymers include polystyrene (PS), polyvinyl
chloride (PVC), polyvinyl chloride (PVdC), ethylene vinyl acetate
(EVA), ethylene vinyl alcohol (EVOH), polyvinyl alcohol (PVOH) and
derivatives or blends/mixtures of these materials.
[0037] Within the context of the invention, the term "polyester"
refers to a polymer that contains an ester functional group in
their main chain. Ester functional group is characterized by a
carbon bound to three other atoms: a single bond to a carbon, a
double bond to an oxygen, and a single bond to an oxygen. The
single bound oxygen is bound to another carbon. According to the
composition of their main chain, polyesters can be aliphatic,
aromatic or semi-aromatic. Polyester can be homopolymer or
copolymer. As an example, polylactic acid is an aliphatic
homopolymer composed of one monomer, lactic acid; and polyethylene
terephthalate is an aliphatic-aromatic copolymer composed of two
monomers, terephthalic acid and ethylene glycol. Such polyesters
may be native or chemically modified.
[0038] In the context of the invention, the term "filler" refers to
a substance that is incorporated to a plastic composition and/or to
a plastic article to reduce the costs thereof or, optionally,
improve the physical properties thereof (e.g., its hardness,
stiffness or strength). Fillers can be inactive (i.e., inert) or
active material, and may form chemical bonds with the components of
the plastic composition or article. The filler can be natural,
synthetic or modified fillers. The filler can be selected from
mineral or organic fillers. In a particular embodiment of the
invention, the mineral filler is chosen from the group consisting
without limitation of calcite, carbonate salts or metal carbonate
such as calcium carbonate (or limestone), potassium carbonate,
magnesium carbonate, aluminium carbonate, zinc carbonate, copper
carbonate, chalk, dolomite, silicate salts such as hydrous
magnesium silicate such as talc or soapstone, calcium silicate
(wollastonite), potassium silicate, magnesium silicates (talc),
aluminium silicate (kaolin), or mix thereof such as mica, smectite
such as montmorillonite, vermiculite, and palygorskite-sepiolite,
sulphate salts such as barium sulfate, or calcium sulfate (gypsum),
mica, hydroxide salt or metal hydroxide such as calcium hydroxide
or potassium hydroxide (potash) or magnesium hydroxide or aluminium
hydroxide or sodium hydroxide (caustic soda), hydrotalcite, metal
oxide or oxide salts such as oxide of magnesium or oxide of calcium
or oxide of aluminium or iron oxide or copper oxide, clay,
asbestos, silica, graphite, carbon black, metal fibers or metal
flakes, glass fibers, magnetic fillers, aramid fibers, ceramic
fibers and derivatives thereof or blends/mixtures of these
materials. Alternatively or in addition, the organic filler is
chosen from the group consisting of wood flour, plant or vegetable
flour such as cereal flour (corn flour, wheat flour, rice flour,
soy bean flour, nutshell flour, clam shell flour, corn cob flour,
cork flour, rice hull flour); saw dust; plant fibers such as flax
fibers, wood fibers, hemp fibers, bamboo fibers, chicken feathers
and derivatives thereof or blends/mixtures of these materials.
Natural polymers can also be used as organic fillers, such as
lignin, or polysaccharides such as cellulose or hemi-cellulose,
starch, chitin, chitosan and derivatives or blends/mixtures of
these materials.
[0039] As used herein, the term "biological entities" designates
active enzymes or enzyme-producing microorganisms, such as
sporulating microorganisms, as well as combinations thereof.
According to the invention, "biological entities" preferably refer
to enzymes. The biological entities may be in solid (e.g., powder)
or liquid form.
[0040] As used herein the term "polysaccharides" refers to
molecules composed of long chains of monosaccharide units bound
together by glycosidic linkages. Polysaccharides structure can be
linear to highly branched. Examples include storage polysaccharides
such as starch and glycogen, and structural polysaccharides such as
cellulose and chitin. Polysaccharides include native
polysaccharides or chemically modified polysaccharides by
cross-linking, oxidation, acetylation, partial hydrolyze, etc.
Carbohydrate polymers may be classified according to their source
(marine, plant, microbial or animal), structure (linear, branched),
and/or physical behavior (such as the designation as gum or
hydrocolloid which refers to the property that these
polysaccharides hydrate in hot or cold water to form viscous
solutions or dispersions at low concentration gum or hydrocolloid).
In the context of the invention, the polysaccharides may be
classified according to the classification described in
"Encapsulation Technologies for Active Food Ingredients and Food
Processing--Chapter 3--Materials for Encapsulation--Christine
Wandrey, Artur Bartkowiak, and Stephen E. Harding": [0041] Starch
and derivatives, such as amylose, amylopectine, maltodextrin,
glucose syrups, dextrin, cyclodextrin. [0042] Cellulose and
derivatives, such as methylcellulose, hydroxypropyl methyl
cellulose, ethyl cellulose, etc. [0043] Plant exudates and
extracts, also called plant gums or natural gums, including but not
limited to gum arabic (or gum acacia), gum tragacanth, guar gum,
locust bean gum, gum karaya, mesquite gum, galactomannans, pectine,
soluble soybean polysaccharide). [0044] Marine extracts such as
carrageenan and alginate. [0045] Microbial and animal
polysaccharides such as gellan, dextran, xanthan and chitosan.
[0046] Polysaccharides can be further classified according to their
solubility in water. Particularly, cellulose is not soluble in
water. According to the invention, the polysaccharides used as a
carrier are soluble in water.
[0047] As used herein the term "ambient temperature" or "room
temperature" means a temperature between 10.degree. C. and
30.degree. C., particularly between 20.degree. C. and 25.degree.
C.
[0048] As used herein, the term "soluble" designates the ability of
a solute (i.e., carrier, enzymes) to be dissolved in a liquid
solvent. The solubility of a substance depends on the physical and
chemical properties of both the solute and solvent, as well as
temperature, pressure and pH of the solution and may be defined
according to international standards such as IUPAC. According to
the IUPAC definition, the solubility is the analytical composition
of a saturated solution expressed as a proportion of a designated
solute in a designated solvent. Solubility may be stated in various
units of concentration such as molarity, molality, mole fraction,
mole ratio, mass (solute) per volume (solvent) and other units.
Solubility is defined at a particular temperature and particular
atmospheric pressure. The extent of solubility ranges widely, from
infinitely soluble (without limit) or fully miscible, such as
ethanol in water, to poorly soluble, such as silver chloride in
water. The term insoluble is often applied to poorly or very poorly
soluble solute. The term "maximum solubility" refers to the
saturation concentration of the solute in a solvent, where an
additional quantity of the solute does not increase the
concentration of the solution and where the excess amount of solute
begins to precipitate. According to the invention, the maximum
solubility refers to the saturation concentration of the carrier in
the liquid composition, wherein other components, such as the
biological entities, may impact on the solute's solubility.
[0049] As used herein, the term "by weight" refers to a quantity
based on the total weight of the considered composition or
product.
[0050] In the context of the invention, the term "about" refers to
a margin of +/-5%, preferably of +/-100, or within the tolerance of
a suitable measuring device or instrument.
Liquid Composition
[0051] It is therefore an object of the invention to provide a
liquid composition suitable to be incorporated in a partially or
totally molten polymer and comprising biological entities having a
polymer-degrading activity, a carrier and an aqueous solvent,
wherein:
i) the carrier is a polysaccharide selected from starch
derivatives, natural gums, marine extracts, microbial and animal
polysaccharides, and ii) the composition comprises, based on the
total weight of the composition: [0052] from 0.01% to 35% of
biological entities [0053] from 15% to 95% of an aqueous solvent
[0054] from 3% to 80% of a carrier.
[0055] According to the invention, the expression "suitable to be
incorporated in a partially or totally molten polymer" means that
the biological entities of the composition retain an activity after
the heat treatment. Particularly, the biological entities retain a
polymer degrading activity in the plastic composition and/or in the
final plastic article.
[0056] In a particular embodiment, the composition is suitable to
be extruded with a polymer. Preferably, the composition is suitable
to be extruded with a synthetic polymer such as polyolefins,
aliphatic or aromatic polyesters, polyamides, polyurethanes and
polyvinyl chloride, or a natural polymer such lignin and
polysaccharides, such as cellulose, hemi-cellulose, starch and
derivatives thereof. In a preferred embodiment, the composition is
suitable to be extruded with a polymer with a low melting
temperature or melting point (Tm), i.e. with a Tm below 140.degree.
C.
[0057] In a preferred embodiment, the aqueous solvent is water. In
such embodiment, the composition comprises, based on the total
weight of the composition, from 15% to 95% of water, and from 5% to
85% of other components, such as, at least, from 0.01% to 35% of
biological entities and from 3% to 80% of a carrier.
[0058] In a particular embodiment, the composition comprises, based
on the total weight of the composition: [0059] from 0.3% to 30% of
biological entities [0060] from 19% to 85% of an aqueous solvent
[0061] from 4% to 80% of a carrier.
[0062] In a preferred embodiment, the composition comprises from
19% to 85% of water and from 15% to 81% of other components, such
as at least from 0.01% to 35% of biological entities and from 3% to
80% of a carrier, based on the total weight of the composition.
In a particular embodiment, the composition comprises less than 35%
by weight of biological entities. In another particular embodiment,
the composition comprises less than 30% by weight of biological
entities.
[0063] In another particular embodiment, the composition comprises
less than 20% by weight of biological entities.
[0064] In preferred particular embodiment, the composition
comprises less than 80% by weight of aqueous solvent, preferably
less than 75%, less than 70%, even more preferably less than 60%,
based on the total weight of the composition. In another preferred
embodiment, the composition comprises more than 20% by weight of
aqueous solvent, preferably more than 30%, and less than 80%, based
on the total weight of the composition. In another particular
embodiment, the composition comprises from 20% to 80% by weight of
aqueous solvent, preferably from 30% to 75%, more preferably from
40% to 60%. In another particular embodiment, the composition
comprises about 50% of aqueous solvent. In another particular
embodiment, the composition comprises about 40% of aqueous
solvent.
[0065] In a preferred embodiment, the aqueous solvent is water. In
a preferred embodiment, the composition comprises less than 75% by
weight of water, preferably less than 70%, more preferably less
than 60%, based on the total weight of the composition. In another
preferred embodiment, the composition comprises more than 20% by
weight of water, preferably more than 30%, and less than 80%, based
on the total weight of the composition. Particularly, the
composition comprises from 20% to 80% by weight of water. In
another particular embodiment, the composition comprises from 30%
to 75% by weight of water, preferably from 40% to 60%. In another
particular embodiment, the composition comprises about 50% of
water. In another particular embodiment, the composition comprises
about 40% of water.
[0066] In preferred particular embodiment, the composition
comprises more than 5% by weight of carrier, preferably more than
10%, even more preferably more than 15%.
[0067] Thus, in a preferred embodiment, the composition comprises,
based on the total weight of the composition: [0068] From 0.3% to
30% by weight of biological entities [0069] From 19% to 60% by
weight of an aqueous solvent [0070] From 15% to 70% by weight of a
carrier.
[0071] In another preferred embodiment, the composition comprises
less than 70% by weight of carrier, preferably less than 60%. In a
particular embodiment, the composition comprises from 5% and 70% of
carrier, preferably from 10% to 60%. In another particular
embodiment, the composition comprises from 10% to 50% of
carrier.
[0072] In another particular embodiment, the composition comprises,
based on the total weight of the composition: [0073] from 0.01% to
35% of biological entities [0074] from 30% to 75% of water [0075]
from 10% to 69.99% of a carrier.
[0076] In another particular embodiment, the composition comprises,
based on the total weight of the composition: [0077] from 0.01% to
35% of biological entities [0078] from 30% to 60% of water [0079]
from 20% to 45% of a carrier.
[0080] In another particular embodiment, the composition comprises,
based on the total weight of the composition: [0081] from 0.01% to
35% of biological entities [0082] from 40% to 60% of water [0083]
from 20% to 45% of a carrier.
[0084] In another particular embodiment, the composition comprises
about 50% of water, and from 0.01% to 35% of biological entities,
and from 20% to 49.99% of carrier.
[0085] In another particular embodiment, the composition comprises
about 40% of water, and from 0.01% to 35% of biological entities,
and from 20% to 59.99% of carrier.
[0086] In a particular embodiment, the ratio carrier/aqueous
solvent by weight is below 4.
[0087] In a particular embodiment, the quantity of carrier in the
composition is from 4% to 100% of the maximum solubility of the
carrier in the aqueous solvent, i.e., from 4% to 100% of the
saturation concentration of the carrier in the aqueous solvent.
[0088] Alternatively, or in addition, the quantity of carrier in
the composition is from 4% to 100% of the maximum solubility of the
carrier in the composition, i.e., from 4% to 100% of the saturation
concentration of the carrier in the composition.
[0089] According to the invention, the presence of particular
carriers in the composition allows to protect and stabilize the
biological entities not only in the composition but also during a
heat treatment, such as an extrusion process wherein the
composition is introduced into a partially or totally molten
polymer.
[0090] In a particular embodiment, the carrier is in a solid form
at ambient temperature. Advantageously, the carrier is also soluble
in aqueous solvent such as water at ambient temperature.
Preferably, the carrier is soluble in the liquid composition, at
least at ambient temperature. Alternatively, or in addition, the
carrier is soluble in the liquid at the temperature at which said
composition is introduced in a polymer which is in partially or
totally molten state.
[0091] In a particular embodiment, the carrier is a starch
derivative. Preferably the carrier is maltodextrin. In such
particular embodiment, the ratio by weight of maltodextrin/aqueous
solvent is preferably between 3 and 4. In a particular embodiment,
the quantity of maltodextrin in the composition is from 5 to 100%
of its maximum solubility in the composition, preferably from 26 to
100%, more preferably from 39 to 100%. Accordingly, the composition
comprises more than 4% by weight of maltodextrin, based on the
total weight of the composition, preferably more than 20%,
preferably more than 30%.
[0092] In a particular embodiment, the carrier is a natural gum.
Preferably the carrier is selected from arabic gum, guar gum,
tragacanth gum, karaya gum, more preferably the carrier is arabic
gum. In a particular embodiment, the ratio by weight arabic
gum/aqueous solvent is between 0.1 and 1, preferably between 0.3
and 0.8, more preferably between 0.35 and 0.6, even more preferably
between 0.4 and 0.5. In another preferred embodiment, the ratio by
weight arabic gum/aqueous solvent is above 0.8, preferably between
0.8 and 1. Particularly, the quantity of arabic gum in the
composition is from 6% to 100% of its maximum solubility in the
composition, preferably from 40% to 100% of its maximum solubility,
preferably from 60% to 100% of its maximum solubility. In another
particular embodiment, the composition comprises more than 4% by
weight of arabic gum, preferably more than 10%, more preferably
more than 15%, even more preferably more than 20%. In another
particular embodiment, the composition comprises less than 70% by
weight of arabic gum, preferably less than 60%. In a particular
embodiment, the composition comprises from 5% and 70% of arabic
gum, preferably from 10% to 60%. In another particular embodiment,
the composition comprises from 10% to 50% of arabic gum.
[0093] In another particular embodiment, the carrier is a marine
extract. Preferably the carrier is selected from carrageenan or
alginate.
[0094] In another particular embodiment, the carrier is a microbial
polysaccharide. Preferably the carrier is xanthan.
[0095] In another particular embodiment, the carrier is an animal
polysaccharide. Preferably the carrier is chitosan.
[0096] In a particular embodiment, the composition comprises at
least two carriers selected from starch derivatives, natural gums,
marine extracts, microbial and animal polysaccharides.
[0097] In another particular embodiment, the ratio by weight
carrier/biological entities is between 0.8 and 1.2, preferably
about 1. In another particular embodiment, the ratio by weight
carrier/biological entities is above 1, preferably above 2.
[0098] According to the invention, the composition may further
comprise sugars, proteins, lipids, organic acids, salts and
vitamins originating from the culture supernatant of a
polymer-degrading microorganism used as biological entities in the
composition. Such supernatant may be preliminary treated (e.g.,
mechanically or physically or chemically) to increase the
concentration of enzymes and/or to remove other components such as
DNA or cell debris.
[0099] In a particular embodiment, the composition may further
comprise polyols, such as glycerol, sorbitol or propylene glycol.
This is particularly the case when producing the composition of the
invention with commercial biological entities, preferably
commercial enzymes, conditioned in a stabilizing solution
comprising polyols. According to a particular embodiment, the
composition comprises at most 10% by weight of polyols based on the
total weight of the composition, preferably at most 5%. According
to another particular embodiment, the composition comprises between
10% and 20% by weight of polyols based on the total weight of the
composition.
[0100] According to a particular embodiment, the composition may
comprise non-soluble components with a particle size below 20
.mu.m.
[0101] Alternatively, or in addition, the composition further
comprises mineral components such as calcium components that are
known to increase the thermostability of some biological entities
such as calcium carbonate, calcium chloride or other calcium
minerals.
[0102] Advantageously, the composition of the invention is stable,
i.e. chemically and biologically stable. In the context of the
invention, "chemically stable" refers to a composition wherein the
biological entities do not show any significant loss of activity
during a defined period at room temperature, in the dark. More
particularly, "chemically stable" refers to a composition wherein
the loss of degrading activity of the biological entities is less
than 50%, preferably less than 25%, more preferably less than 10%
as compared to the degrading activity of said biological entities
before introduction in the composition, during a period of time of
at least 30 days, preferably at least 90 days, more preferably at
least 1 year. In a particular embodiment, the composition of the
invention is advantageously chemically stable during at least 90
days at 4.degree. C. Particularly, the loss of degrading activity
of the biological entities in the composition of the invention is
less than 10% as compared to the degrading activity of said
biological entities before introduction in the composition, during
a period of time of at least 90 days.
[0103] In the context of the invention, the term "biologically
stable" refers to a composition that does not show any subsequent
bacterial, yeast of fungal proliferation during a defined period of
at least 30 days, preferably at least 90 days, more preferably at
least 1 year, at room temperature, in the dark. Particularly, the
composition further comprises antifungal and/or antibacterial
components, such as sorbic acid and/or salts thereof, benzoic acid
and salts thereof, sulfurous anhydride or sulfite, nitrate or
nitrite, propionic acid, butyric acid, natamycin, paraben, acetic
acid, citric acid, boric acid, vegetal extracts.
[0104] In another particular embodiment, the composition comprises,
based on the total weight of the composition: [0105] from 0.01% to
35% of PLA-degrading enzymes, [0106] from 30% to 75% of water, and
[0107] from 10% to 69.99% of arabic gum.
[0108] In another particular embodiment, the composition comprises,
based on the total weight of the composition: [0109] from 0.01% to
35% of PLA-degrading enzymes, [0110] from 30% to 60% of water, and
[0111] from 20% to 45% of arabic gum.
[0112] In another particular embodiment, the composition comprises,
based on the total weight of the composition: [0113] from 0.01% to
35% of PLA-degrading enzymes, [0114] from 40% to 60% of water, and
[0115] from 20% to 45% of arabic gum.
[0116] In another particular embodiment, the composition comprises
about 50% of water, and from 0.01% to 35% of PLA-degrading enzymes,
and from 20% to 49.99% of arabic gum.
In another particular embodiment, the composition comprises about
40% of water, and from 0.01% to 35% of PLA-degrading enzymes, and
from 20% to 59.99% of arabic gum.
[0117] All the compositions set above may optionally comprise from
0% to 20% preferably from 0% to 5%, by weight based on the total
weight of the composition, of other components, preferably selected
from proteins, salts, and polyols.
[0118] In a particular embodiment, the PLA-degrading enzymes of
such compositions are preferably proteases.
[0119] In a particular embodiment, the composition of the invention
comprises, based on the total weight of the composition: [0120]
from 20% to 80% by weight of water, preferably from 40% to 60% of
water, [0121] from 0.01% to 30% by weight of PLA-degrading enzymes,
preferably from 5% to 30% of PLA-degrading enzymes such as
protease, and [0122] from 10% to 50% by weight of arabic gum,
preferably from 15% to 35%.
[0123] In a particular embodiment, the composition of the invention
comprises, based on the total weight of the composition: [0124]
from 20% to 80% by weight of water, preferably from 40% to 60% of
water, [0125] from 0.01% to 30% by weight of PLA-degrading enzymes,
preferably from 5% to 30% of PLA-degrading enzymes such as
protease, [0126] from 10% to 50% by weight of arabic gum,
preferably from 15% to 35%, and [0127] from 0% to 20% by weight of
other components, preferably selected from proteins, salts, and
polyols. In a particular embodiment, the composition of the
invention comprises, based on the total weight of the composition:
[0128] from 20% to 80% by weight of water, preferably from 40% to
60% of water, [0129] from 0.01% to 30% by weight of PLA-degrading
enzymes, preferably from 5% to 30% of PLA-degrading enzymes such as
protease, and [0130] from 10% to 50% by weight of maltodextrin,
preferably from 15% to 40%. In a particular embodiment, the
composition of the invention comprises, based on the total weight
of the composition: [0131] from 20% to 80% by weight of water,
preferably from 40% to 60% of water, [0132] from 0.01% to 30% by
weight of PLA-degrading enzymes, preferably from 5% to 20% of
PLA-degrading enzymes such as protease, [0133] from 10% to 50% by
weight of maltodextrin, preferably from 15% to 40%, and [0134] from
0% to 20% of other components, preferably selected from proteins,
salts, and polyols.
[0135] Advantageously, the liquid composition is in a liquid form
at least at ambient temperature. Preferably, the liquid composition
is in a liquid form at the temperature at which said composition is
introduced in a polymer which is in partially or totally molten
state.
[0136] Advantageously, in all compositions stated above, the
quantity of carrier and biological entities are expressed on a dry
matter basis, i.e. on the quantity of such carrier and biological
entities after full dehydration, water evaporation or water
removing. Accordingly, the quantity of aqueous solvent in the
composition includes all the liquid parts of the constituents of
the composition such as the liquid part of the biological entities
when introduced under a liquid form and/or the residual water that
may be contained in the carrier (even when supplied under a powder
form).
Biological Entities
[0137] According to the invention, the composition comprises
biological entities suitable for degrading at least one polymer. In
another particular embodiment, the composition comprises biological
entities suitable for degrading at least two polymers.
[0138] In a preferred embodiment, the biological entities comprise
at least an enzyme with polymer-degrading activity and/or at least
a microorganism expressing, and optionally excreting, an enzyme
having a polymer-degrading activity. In a particular embodiment,
the biological entities comprise or consist in at least an enzyme
with synthetic polymer-degrading activity and/or at least a
microorganism expressing, and optionally excreting, an enzyme
having a synthetic polymer-degrading activity. In a preferred
embodiment, the biological entities consist in at least an enzyme
with synthetic polymer-degrading activity. In another particular
embodiment, the biological entities comprise or consist in at least
two enzymes with polymer-degrading activity. Examples of suitable
enzymes having a polymer-degrading activity for use in the
invention include, without limitation, depolymerase, esterase,
lipase, cutinase, hydrolase, protease, polyesterase,
carboxylesterase, oxygenase and/or oxidase such as laccase,
peroxidase or oxygenase.
[0139] In a particular embodiment, the biological entities comprise
or consist in at least an enzyme with polyester-degrading activity
and/or at least a microorganism expressing, and optionally
excreting, an enzyme having a polyester-degrading activity.
Examples of suitable enzymes having a polyester-degrading activity
for use in the invention include, without limitation, depolymerase,
esterase, lipase, cutinase, carboxylesterase, protease, or
polyesterase. In another particular embodiment, the biological
entities comprise or consist in at least two enzymes with
polyester-degrading activity.
[0140] The enzymes may be in pure or enriched form, or in mixture
with other excipients or diluents. A combination of enzymes may be
used as well.
[0141] In a preferred embodiment, the biological entities comprise
or consist in an enzyme with a PLA-degrading activity. More
preferably, the biological entities consist in an enzyme with a
PLA-degrading activity. The biological entities is a protease,
preferably selected from Amycolatopsis sp., Amycolatopsis
orientalis, proteinase K from Tritirachium album, Actinomadura
keratinilytica, Laceyella sacchari LP175, Thermus sp., Bacillus
licheniformis, Bacillus thermoproteolyticus or any reformulated
(i.e., diafiltrated to remove commercial carrier) commercial
enzymes known for degrading PLA such as SAVINASE, ESPERASE,
EVERLASE, PROTEX, OPTIMASE, MULTIFECT or any enzymes from the
family of the subtilisin CAS 9014-01-1 or any functional variant
thereof. In an alternative embodiment, the biological entities
comprise microorganisms that produce such enzymes, either naturally
or as a result of particular engineering (e.g., recombinant
microorganisms). Preferred examples of suitable microorganisms
include, without limitation, bacteria, fungi and yeasts. In an
embodiment, the biological entities comprise sporulating
microorganisms and/or spores thereof.
[0142] In a particular embodiment, the biological entities comprise
enzymes encapsulated in nanocapsules, enzymes encapsulated in cage
molecules, and enzymes aggregated together. The term "cage
molecule" designates a molecule that can be inserted into the
structure of said enzymes to stabilize them and to make them
resistant to high temperatures. Encapsulation techniques are well
known to those skilled in the art and include, for instance,
nano-emulsions.
[0143] The biological entities may be supplied in a liquid or solid
form. For instance, the biological entities may be in a powder
form. Alternatively, the biological entities may be supplied in
suspension or dissolved in a liquid. In such case, the amounts of
biological entities disclosed in the present specification
correspond preferably to the amounts of biological entities on dry
matter basis (i.e., deprived of the liquid).
Production of the Composition of the Invention
[0144] It is also another object of the invention to provide a
method for producing the liquid composition.
[0145] As stated above the biological entities may be supplied in a
liquid or solid form.
[0146] Liquid biological entities, including commercial enzymes
and/or culture supernatant of a polymer-degrading microorganism,
may be submitted to a pretreatment in order to increase the
concentration of enzymes and/or to remove undesired components.
Particularly, biological entities in a liquid form may be submitted
to filtration, ultrafiltration or diafiltration. This step is
particularly useful for liquid commercial compositions that are
usually sold in water solutions containing polyols. The resulting
liquid solution is then mixed with the carrier in a powder form and
the volume is adjusted with aqueous solvent to obtain the
composition of the invention. The mixture is then submitted to
agitation in order to homogenize the composition of the
invention.
[0147] Biological entities in a solid form, preferably in a powder
form, are mixed with the carrier in a powder form and the aqueous
solvent in order to obtain the composition of the invention. The
mixture is then submitted to agitation in order to homogenize the
composition of the invention.
[0148] The composition of the invention obtained is a solution that
may contain insoluble components with a particle size below 20
.mu.m in suspension in the aqueous solvent.
Use of the Composition of the Invention
[0149] It is also another object of the invention to provide
methods using the composition of the invention. Particularly, the
composition of the invention is used for the production of a
plastic composition, such plastic composition being further used
for the production of a plastic article. According to the
invention, the composition of the invention is particularly useful
for the production of thin plastic articles such as plastic films.
Indeed, the absence of particles with particle size above 20 .mu.m
reduces the roughness at the surface of the film.
[0150] In a preferred embodiment, the composition of the invention
is used for the production of a plastic article wherein the
biological entities of the composition are able to degrade at least
one polymer of the plastic article.
[0151] Generally speaking, the liquid composition of the invention
is introduced in a polymer in a partially or totally molten step
before or during shaping of said polymer to produce a biodegradable
plastic article. According to the invention, the biological
entities of the composition retain an activity after their
introduction in a polymer in a partially or totally molten
state.
[0152] In a particular embodiment, the liquid composition is
introduced in a first polymer that has a melting temperature (Tm)
above 140.degree. C. In another particular embodiment, the liquid
composition is introduced in a first polymer that has a low Tm
(below 140.degree. C., preferably below 120.degree. C.), such as
PCL, PBSA, PBAT, PHA or PLA. With regards to amorphous polymer, in
the context of the invention, the Tm refers to the transformation
temperature at which the amorphous polymer is fluid enough to be
processed by extrusion (i.e., in a rubbery or softened state). The
resulting mixture is then added to a second polymer that has a high
melting point, such as PLA. For instance, the liquid composition is
added to PCL that has been heated at about 70.degree. C. to be in
partially molten state. Then, the mixture is directly added to PLA
that was heated to about 150.degree. C. or above to be in a
partially molten state. Alternatively, the mixture may be cooled
and optionally conditioned before to be added to the second
polymer.
[0153] Advantageously, the residence time of the liquid composition
and thereby of the biological entities in the first polymer at a
temperature above 100.degree. C. is as short as possible and
preferably comprised between 5 seconds and 10 minutes, more
preferably less than 5 minutes, 3 minutes, 2 minutes.
[0154] It is an object of the invention to provide a process for
preparing a plastic article using a masterbatch.
[0155] For instance, the process comprises the steps of:
a) preparing a masterbatch comprising polymer-degrading biological
entities and at least a first polymer by (i) heating the first
polymer; and (ii) introducing from 5% to 50% by weight of the
composition as described above, based on the total weight of the
masterbatch during heating of the first polymer; and (b)
introducing the masterbatch in a polymer-based matrix during
production of the plastic article.
[0156] Wherein step a) is performed at a temperature at which the
first polymer is in a partially or totally molten state and step b)
is performed at a temperature at which both the first polymer and
the polymer of the polymer-based matrix are in a partially or
totally molten state and wherein the biological entities of the
composition are able to degrade a polymer of the polymer-based
matrix.
[0157] The step (a) of mixing may thus be performed at a
temperature at or above 40.degree. C., particularly at or above
45.degree. C., 55.degree. C., 60.degree. C., 70.degree. C.,
80.degree. C., 90.degree. C., 100.degree. C., or even above
150.degree. C., depending on the nature of the first polymer.
Typically, this temperature does not exceed 300.degree. C. More
particularly, the temperature does not exceed 250.degree. C. In a
particular embodiment, step (a) is performed using a polymer with a
Tm above 140.degree. C. In a preferred embodiment, step (a) is
performed using a polymer with low melting point, i.e. with a
melting point below 140.degree. C. For instance, step (a) is
performed using PCL, PBAT, PLA, PHA or PBSA. The temperature of the
mixing step can be adapted by a person skilled in the art depending
on the type of polymer, and/or biological entities used for the
production of the masterbatch. Particularly, the temperature is
chosen according to the melting point, or melting temperature of
the first polymer. In a particular embodiment, step (a) is
performed at the melting point of the first polymer. The polymer is
then in a partially or totally molten state. In another embodiment,
step (a) is performed at a temperature above the glass transition
temperature of said polymer, particularly between the glass
transition temperature (Tg) and the melting temperature of said
polymer. In another particular embodiment, the step (a) of mixing
is performed at a temperature above the melting temperature of said
polymer.
[0158] In a particular embodiment, the first polymer has a melting
temperature below 140.degree. C. According to the invention, the
first polymer is heated at a temperature below 140.degree. C., and
the composition is introduced into the first polymer during said
heating step. In another particular embodiment, the first polymer
has a melting temperature above 140.degree. C. According to the
invention, the first polymer is heated at a temperature above
140.degree. C., and the composition is introduced into the first
polymer during said heating step. More generally speaking, the step
of preparation of the masterbatch (step a) is performed at a
temperature at which the first polymer is in a partially or totally
molten state, so that the biological entities of the composition
are embedded into the first polymer during the extrusion.
Preferably, step a) is performed by extrusion.
[0159] In preferred embodiment, the masterbatch is prepared by (i)
extruding a first polymer, wherein said first polymer has a melting
temperature below 140.degree. C. and (ii) introducing the
composition during extrusion of the first polymer, before to
introduce said masterbatch into a polymer-based matrix in order to
prepare the plastic article. In another embodiment, the masterbatch
is prepared by (i) extruding a first polymer, wherein said first
polymer has a melting temperature above 140.degree. C. and (ii)
introducing the composition during extrusion of the first polymer,
before to introduce said masterbatch into a polymer-based matrix in
order to prepare the plastic article.
[0160] In a particular embodiment, the first polymer is a
polyester, preferably selected from polycaprolactone (PCL),
poly(butylene succinate) (PBS), poly butylene succinate adipate
(PBSA), polybutylene adipate terephthalate (PBAT),
polyhdroxyalkanoate (PHA), polylactic acid (PLA), or copolymers. In
another particular embodiment, the first polymer is a natural
polymer, preferably selected from starch. In another particular
embodiment, the masterbatch comprises a "universal" polymer, i.e.,
a polymer that is compatible with a broad range of polymers, such
as a copolymer (e.g. ethylene vinyl acetate copolymer EVA).
[0161] In a particular embodiment, the masterbatch comprises a
first polymer that has a melting temperature below 140.degree. C.
and/or a glass transition temperature below 70.degree. C.
Preferably, the first polymer of the masterbatch has a melting
temperature below 120.degree. C., and/or a glass transition
temperature below 30.degree. C. For instance, such first polymer is
selected from the group consisting of PCL, PBS, PBSA, PBAT, PLA and
EVA. Preferably, such first polymer is selected from the group
consisting of PCL, PBAT, EVA and PLA and mixtures thereof. In a
particular embodiment, the first polymer is PCL. In another
particular embodiment, the first polymer is PLA. The advantage of
such embodiment is to reduce the heating of the biological entities
in the composition during the masterbatch production process.
[0162] The masterbatch comprises between 5% and 50% by weight of
the liquid composition, based on the total weight of the
masterbatch. Preferably, the composition of the invention
represents between 10% and 40%, more preferably between 10% and
30%. In a particular embodiment, the masterbatch comprises about
20% by weight of the composition of the invention, based on the
total weight of the masterbatch. In another particular embodiment,
the masterbatch comprises about 10% by weight of the composition of
the invention, based on the total weight of the masterbatch. In a
particular embodiment, the polymer-degrading biological entities of
the composition are able to degrade the first polymer.
Alternatively, or in addition, the polymer-degrading biological
entities are able to degrade at least one polymer of the final
plastic article that incorporates the masterbatch.
[0163] The masterbatch may further comprise one or several
additional compounds. In particular, the masterbatch may further
comprise one or more additives. Generally speaking, the additives
are used in order to enhance specific properties in the final
product. For instance, the additives may be selected from the group
consisting without limitation of plasticizers, coloring agents,
processing aids, rheological agents, anti-static agents, anti-UV
agents, toughening agents, impact modifiers, compatibilizers, slip
additives, flame retardant agents, anti-oxidants, pro-oxidants,
light stabilizers, oxygen scavengers, adhesives, products,
excipients, slip additives. Advantageously, the masterbatch
comprises less than 20% by weight of such additives, preferably
less than 10%, typically between 0.1 and 10% by weight of such
additives. Preferably, the masterbatch comprises at least one
additive selected from plasticizers, slip additives and light
stabilizers. Particularly, the masterbatch may further comprise at
least one filler. The filler can be selected from any conventional
filler used in the plastic industry. The type and exact quantity of
fillers can be adapted by a person skilled in the art depending on
the type of masterbatch composition. Advantageously, the
masterbatch comprises at least one filler selected from anti-acids
filler such calcium carbonate, talc or silica.
[0164] In a particular embodiment, the masterbatch composition
comprises, based on the total weight of the masterbatch: [0165]
from 50% to 95% by weight of a first polymer; [0166] from 5% to 50%
by weight of the liquid composition comprising polymer-degrading
biological entities; and optionally [0167] at least one
additive.
[0168] In another particular embodiment, the masterbatch comprises,
based on the total weight of the masterbatch: [0169] from 70% to
90% by weight of a first polymer; [0170] from 10% to 30% by weight
of the liquid composition comprising polymer-degrading biological
entities; and optionally [0171] at least one additive.
[0172] In another particular embodiment, the masterbatch comprises,
based on the total weight of the masterbatch: [0173] from 70% to
80% by weight of a first polymer; [0174] from 10% to 20% by weight
of the liquid composition comprising polymer-degrading biological
entities; and optionally [0175] at least one additive.
[0176] In a particular embodiment, the masterbatch comprises, based
on the total weight of the masterbatch: [0177] from 70% to 80% by
weight of PCL; [0178] from 10% to 20% by weight of the liquid
composition comprising PLA-degrading biological entities; and
optionally [0179] at least one additive.
[0180] In another particular embodiment, the masterbatch comprises,
based on the total weight of the masterbatch: [0181] from 70% to
80% by weight of PLA; [0182] from 10% to 20% by weight of the
liquid composition comprising PLA-degrading biological entities;
and optionally [0183] at least one additive.
[0184] In a particular embodiment, the masterbatch is produced by a
process called "compounding", usually an extrusion-granulation
process, in which the first polymer is melted and mixed with the
composition of the invention. Compounding combines mixing and
blending techniques during a heat process, in order to ensure
uniformity, homogeneity and dispersion in the masterbatch. The
compounding is a technique known by a person skilled in the art.
Such compounding process may be carried out with an extruder, such
as single-screw extruders, multi-screw extruders of either
co-rotating or counter-rotating design, dispersive kneaders,
reciprocating single-screw extruder (co-kneaders).
[0185] More generally, the step (a) of preparing the masterbatch
may be carried out with an extruder, wherein the first polymer is
heated, melted and mixed with the composition. The first polymer
may be introduced in the extruder in a powder or granulated form,
preferably in a granulated form.
[0186] In a preferred embodiment, the extruder used for the
production of the masterbatch of step (a) is a multi-screw
extruder, preferably a twin-screw extruder, more preferably a
co-rotative twin-screw extruder. In a particular embodiment, the
extruder further comprises, after the screws, a static mixer. In
another embodiment, the extruder is used with a die pierced with
holes, preferably at least a two holes die. In another preferred
embodiment, the extruder is used with a one-hole die. One skilled
in the art will easily adapt the characteristics of the die (e.g.
the number and size of the holes, etc.), to the pressure, the
output or the masterbatch intended.
[0187] In a preferred embodiment, the residence time of the mixture
of first polymer and the composition in the extruder is comprised
between 5 seconds and 3 minutes, preferably is less than 2 minutes.
When the masterbatch comprises a polymer with a melting temperature
below 120.degree. C., the residence time of the mixture is
comprised between 5 seconds and 10 minutes in the extruder,
preferably less than 5 minutes.
[0188] One skilled in the art will easily adapt the characteristics
of the extruder (e.g., the length and diameter of the strew(s), the
screws profile, degassing zones etc.), and the residence time to
the first polymer, the composition and the type of masterbatch
intended.
[0189] Particularly, such extruder may contain a principal hopper
and several successive heating zones, wherein the temperature may
be independently controlled and regulated and wherein additional
components may be added at different time during the process.
Vacuum and natural degassing zone are necessary during the
extrusion to remove the volatile products like water.
[0190] The liquid composition is introduced with a pump. In a
particular embodiment, the liquid composition is introduced at a
late stage of the mixing step (i.e., in the last heating zones),
and more particularly when the first polymer is in a partially or
totally molten state. Thus, the exposure of biological entities to
elevated temperature is reduced. Preferably, the residence time of
the liquid composition in the extruder is half as long as the
residence time of the first polymer, or less. In another particular
embodiment, the liquid composition of the invention is introduced
before the polymer in the extruder. Thus, the contact between the
liquid composition and the polymer is increased.
[0191] According to the invention, after step (a) of preparing the
masterbatch, said masterbatch may be conditioned in any suitable
solid form. In this regard, in a preferred embodiment, the
masterbatch is shaped into a rod through a die. The rod is then
cooled, before to be chopped in the form of granulates and/or
pastilles of masterbatch and optionally dried. An
underwater-pelletizer may be used as well. In a further embodiment,
said granulates of masterbatch may be pulverized or micronized to
produce a powder of said masterbatch. It is then possible to submit
the powder to an extrusion-granulation process, preferably in an
extruder so that the mixture is in a partially or totally molten
state, before step (b).
[0192] According to the process of the invention, the masterbatch
is introduced during step (b) in a polymer-based matrix in order to
produce a plastic article. The step of introducing the masterbatch
in the polymer-based matrix is performed at a temperature at which
both the first polymer and at least a polymer of the polymer-based
matrix are in a partially or totally molten state. When the
masterbatch issued of step (a) and the polymer-based matrix are in
a granulated form, it is possible to submit the granulates to a
step of dry-mixing before the step (b) of introduction of the
masterbatch in the polymer-based matrix.
[0193] The polymer-based matrix comprises at least one polymer
selected from natural or synthetic polymers, and/or derivatives
and/or mixtures thereof. One skilled in the art is able to choose
the polymer(s) of the polymer-based matrix depending on the nature
of the final plastic article.
[0194] In a particular embodiment, step (b) is performed using a
polymer with high melting point, i.e. with a melting point above
140.degree. C. For instance, step (b) is performed using PLA.
[0195] In a particular embodiment, the polymer-based matrix
comprised at least one polymer selected from synthetic
polymers.
[0196] In a particular embodiment, the polymer-based matrix
comprises at least one polyester chosen among copolymers of lactic
acid and/or succinic acid and/or terephthalic acid or mix thereof.
Advantageously, the polyester-based matrix comprises at least one
polyester chosen among polylactic acid (PLA), polyglycolic acid
(PGA), polyhydroxyalkanoate (PHA), polycaprolactone (PCL),
polybutylene succinate (PBS), polybutylene succinate adipate
(PBSA), polybutylene adipate terephthalate (PBAT), and derivatives
or blends/mixtures thereof. In a preferred embodiment, the
polyester-based matrix comprises at least one polyester chosen
among PLA and/or PCL and/or PBAT, more preferably PLA.
[0197] According to another particular embodiment, the
polymer-based matrix comprises at least one polymer selected from
natural polymers. Natural polymers may be selected from the group
of lignin, polysaccharides such as cellulose or hemi-cellulose,
starch, chitin, chitosan, and derivatives thereof or
blends/mixtures thereof. In a particular embodiment, the natural
polymers are plasticized (e.g., by a plasticizer such as water or
glycerol) prior to their use for producing the masterbatch
composition. Such plasticizing step modifies the chemical structure
of the natural polymers allowing their use through a plastic
production process.
[0198] Particularly, the polymer-based matrix may further comprise
at least one filler and/or at least one additive. The filler can be
selected from any conventional filler used in the plastic industry.
The type and exact quantity of fillers can be adapted by a person
skilled in the art depending on the type of masterbatch
composition. Advantageously, the plastic article comprises at least
one filler selected from calcium carbonate, talc or silica.
[0199] Advantageously, the plastic article comprises less than 20%
by weight of such additives, preferably less than 10%, more
preferably less than 5%, typically between 0.1 and 4% by weight of
such additives, based on the total weight of the plastic article.
Alternatively, the plastic article comprises between 5% to 10% by
weight of such additives.
[0200] It is also the purpose of the invention to provide a process
wherein a polymer-based matrix is mixed with a masterbatch that
comprises a high amount of biological entities to realize a plastic
article in which the biological entities are precisely added and
homogeneously distributed.
[0201] According to the invention, after step (a) of mixing, and
the optional conditioning of the mixture in a suitable solid form,
the plastic composition produced is (b) shaped into a plastic
article.
[0202] Advantageously, step (b) is implemented at a temperature at
which the polymer of the polymer-based matrix and the first polymer
are in a partially or totally molten state. For instance, step (b)
may be performed at a temperature at or above 40.degree. C.,
particularly at or above 45.degree. C., 55.degree. C., 60.degree.
C., 70.degree. C., 80.degree. C., 90.degree. C., 100.degree. C., or
even above 150.degree. C., depending on the nature of the polymer.
Typically, this temperature does not exceed 300.degree. C. More
particularly, the temperature does not exceed 250.degree. C. The
temperature of the step (b) can be adapted by a person skilled in
the art depending on the type of masterbatch and polymer-based
matrix, and/or the kind of plastic articles intended. Particularly,
the temperature is chosen according to the melting point, or
melting temperature of the polymer of the polymer-based matrix and
of the first polymer.
[0203] In a particular embodiment, step (b) is performed at the
melting point of the polymer of the polymer-based matrix. The
polymer is then in a partially or totally molten state. In another
embodiment, step (b) is performed at a temperature between the
glass transition temperature (Tg) and the melting point of said
polymer. In another particular embodiment, step (b) is performed at
a temperature above the melting point of said polymer.
[0204] Typically, said step (b) may be carried out by extrusion,
extrusion-compounding, extrusion blow-molding, blown film
extrusion, cast film extrusion, calendering and thermoforming,
injection-molding, compression molding, extrusion-swelling, rotary
molding, ironing, coating, stratification, expansion, pultrusion,
compression-granulation, or 3D printing. Such operations are well
known by the person skilled in the art, who will easily adapt the
process conditions according to the kind of plastic articles
intended (e.g., temperature, residence time, etc.). As an example,
blown-film and cast film extrusion are particularly suited for the
production of plastic films. As another example, calendering
process is particularly suited for the production of plastic
sheets, and injection-molding, thermoforming, blow molding,
rotomolding or 3D printing are particularly suited for the
production of rigid plastic articles.
[0205] In a particular embodiment, step (b) is implemented with a
solid masterbatch under a powder or granulated form, preferably
under a granulated form.
[0206] In a particular embodiment, 0.5 to 30% by weight of
masterbatch are added to the polymer-based matrix, based on the
total weight of the plastic article, preferably less than 20%, more
preferably less than 15%, and even more preferable less than 10%.
In a particular embodiment, about 5% by weight of masterbatch is
introduced in the polymer-based matrix. In a particular embodiment,
about 10% by weight of masterbatch is introduced in the
polymer-based matrix.
[0207] In another particular embodiment, 1% to 5% by weight of
masterbatch is incorporated and/or mixed with 95% to 99% by weight
of a polymer-based matrix in a partially or totally molten
state.
[0208] In another particular embodiment, the present invention
relates to a process for preparing a plastic article comprising at
least PLA, comprising the steps of
a) preparing a masterbatch comprising PLA-degrading biological
entities and PCL by; (i) heating PCL; and (ii) introducing from 5%
to 50% by weight of a liquid composition of the invention
containing PLA-degrading biological entities based on the total
weight of the masterbatch during heating of PCL; and (b)
introducing the masterbatch in a PLA-based matrix during
manufacture of the plastic article; wherein step a) is performed at
a temperature at which PCL is in a partially or totally molten
state, preferably above 65.degree. C., more preferably about
70.degree. C. and step b) is performed at a temperature at which
both PCL and PLA are in a partially or totally molten state,
preferably above 120.degree. C., more preferably about 155.degree.
C.
[0209] In another particular embodiment, the present invention
relates to a process for preparing a plastic article comprising at
least PLA, comprising the steps of
a) preparing a masterbatch comprising PLA-degrading biological
entities and PLA by; (i) heating PLA; and (ii) introducing from 5%
to 50% by weight of a liquid composition of the invention
containing PLA-degrading biological entities based on the total
weight of the masterbatch in PLA, during heating of PLA; and (b)
introducing the masterbatch in a PLA-based matrix during
manufacture of the plastic article, wherein step a) is performed at
a temperature at which PLA is in a partially or totally molten
state, preferably above 100.degree. C., more preferably about
130.degree. C. and step b) is performed at a temperature at which
both PLA of the masterbatch and PLA of the PLA-based matrix are in
a partially or totally molten state, preferably above 120.degree.
C., more preferably about 155.degree. C.
[0210] In another embodiment, the liquid composition of the
invention is directly introduced in the polymer(s) that composes
the plastic article.
[0211] It is also an object of the invention to provide a process
for preparing a plastic article, comprising: [0212] a step (a) of
mixing less than 11%, particularly between 0.1% to 10% by weight of
the composition as described above based on the total weight of the
mixture, with at least one polymer, wherein the biological entities
of the composition are able to degrade said polymer and, [0213] a
step (b) of shaping said mixture of step (a) in a plastic
article.
[0214] In a particular embodiment, the process further comprises a
step of mixing at least one additive and/or at least a second
synthetic polymer and/or a natural polymer with the polymer and
biological entities, before step (b). Alternatively, such additive
and/or polymer(s) can be mixed in step (a) with the polymer and
biological entities.
[0215] In a particular embodiment, the polymer used in step (a) is
under a granulated form. In another embodiment, the polymer is
under powder form. To this aim, the polymer can be mechanically
pre-treated before step (a) of mixing, to lead to such powder
forms. Particularly, the polymer may be crushed.
[0216] Step (a) of mixing is performed at a temperature at which
the polymer is in a partially or totally molten state. The step (a)
of mixing may thus be performed at a temperature at or above
40.degree. C., particularly at or above 45.degree. C., 55.degree.
C., 60.degree. C., 70.degree. C., 80.degree. C., 90.degree. C.,
100.degree. C., or even above 150.degree. C., depending on the
nature of the polymer. Typically, this temperature does not exceed
300.degree. C. More particularly, the temperature does not exceed
250.degree. C. The temperature of the mixing step can be adapted by
a person skilled in the art depending on the type of polymer,
and/or composition used for the production of the plastic article.
Particularly, the temperature is chosen according to the melting
point, or melting temperature of the polymer. In a particular
embodiment, step (a) of mixing is performed at the melting point of
the polymer of the plastic article. The polymer is then in a
partially or totally molten state. In another embodiment, step (a)
of mixing is performed at a temperature above the glass transition
temperature of said polymer, particularly between the glass
transition temperature (Tg) and the melting temperature of said
polymer. In another particular embodiment, the step (a) of mixing
is performed at a temperature above the melting temperature of said
polymer.
[0217] In a particular embodiment, the plastic composition from
step a) may be produced by a process called "compounding", usually
an extrusion-granulation process, in which the polymer is melted
and mixed with the composition of the invention. Compounding
combines mixing and blending techniques during a heat process, in
order to ensure uniformity, homogeneity and dispersion in the final
compound. The compounding is a technique known by a person skilled
in the art. Such compounding process may be carried out with an
extruder, such as single-screw extruders, multi-screw extruders of
either co-rotating or counter-rotating design, dispersive kneaders,
reciprocating single-screw extruder (co-kneaders).
[0218] Preferably, the step (a) of mixing the polymer(s) and liquid
composition may be carried out with an extruder, wherein the
polymer is heated and melted and mixed with the composition of the
invention. The polymer may be introduced in the extruder in a
powder or granulated form, preferably in a granulated form.
[0219] According to a particular embodiment, step (a) of mixing
comprises a first step of introducing the liquid composition in a
first polymer that has a low melting point (below 140.degree. C.,
preferably below 120.degree. C.), such as PCL, PBS, PBSA, PLA, PHA,
PBAT; and a second step wherein a polymer-based matrix comprising a
second polymer that has a high melting point, such as PLA, is then
added to the mixture resulting of the first step. For instance, the
liquid composition is added to PCL that has been heated at about
70.degree. C. to be in partially molten state. Then, PLA that was
heated to about 150.degree. C. to be in a partially molten state is
directly added to the mixture.
[0220] In a preferred embodiment, the extruder used for the
production of the plastic composition of step a) is a multi-screw
extruder, preferably a twin-screw extruder, more preferably a
co-rotative twin-screw extruder. In a particular embodiment, the
extruder further comprises, after the screws, a static mixer. In
another embodiment, the extruder is used with a die pierced with
hole(s).
[0221] In a preferred embodiment, the residence time of the mixture
in the extruder is comprised between 5 seconds and 3 minutes,
preferably is less than 2 minutes. When the plastic composition
comprises a polymer with a melting temperature below 120.degree.
C., the residence time of the mixture in the extruder is preferably
less than 5 minutes.
[0222] One skilled in the art will easily adapt the characteristics
of the extruder (e.g., the length and diameter of the screw(s), the
screw(s) profile, degassing zones etc.), and the residence time to
the polymer, the liquid composition of biological entities, and the
type of plastic composition intended.
[0223] Particularly, such extruder may contain a principal hopper
and several successive heating zones, wherein the temperature may
be independently controlled and regulated and wherein additional
components may be added at different time during the process.
Vacuum and natural degassing zone are necessary during the
extrusion to remove the volatile products like water.
[0224] The liquid composition is introduced with a pump. In a
particular embodiment, the liquid composition comprising biological
entities is introduced at a late stage of the mixing step (i.e., in
the last heating zones), and more particularly when the polymer is
in a partially or totally molten state. Thus, the exposure to
elevated temperature is reduced. Preferably, the residence time of
the liquid composition in the extruder is half as long as the
residence time of the polymer, or less. In another particular
embodiment, the liquid composition of the invention is introduced
before the polymer in the extruder. Thus the contact between the
liquid composition and the polymer is increased.
[0225] According to the invention, after step (a) of mixing, the
mixture may be conditioned in any suitable solid form. In this
regard, in a preferred embodiment, the mixture issued from step (a)
is shaped into a rod through a die. The rod is then cooled, and
optionally dried before to be chopped in the form of granulates of
plastic composition. In a further embodiment, said granulates of
plastic composition may be pulverized or micronized to produce a
powder of said plastic composition.
[0226] The polymer may be selected from synthetic polymers. In a
particular embodiment, the polymer is selected from aliphatic
polyesters, preferably from PLA.
[0227] In another particular embodiment, the process further
comprises a step of mixing at least one additive and/or at least a
second polymer and/or at least a filler with the polymer and the
composition, before step (b). Alternatively, such additive and/or
polymer and/or filler can be mixed in step (a) with the polymer and
the composition of the invention.
[0228] The second polymer may be selected from natural or synthetic
polymers. The filler can be selected from any conventional filler
used in the plastic industry. Advantageously, the plastic article
comprises at least one filler selected from calcium carbonate, talc
or silica. Advantageously, the plastic article comprises less than
20% by weight of such additives, preferably less than 10%, more
preferably less than 5%, typically between 0.1 and 4% by weight of
such additives.
[0229] According to the invention, after step (a) of mixing, and
the optional conditioning of the mixture in a suitable solid form,
the plastic composition produced is (b) shaped into a plastic
article.
[0230] Advantageously, step (b) is implemented at a temperature at
which the polymer of the plastic composition is in a partially or
totally molten state. For instance, step (b) may be performed at a
temperature at or above 40.degree. C., particularly at or above
45.degree. C., 55.degree. C., 60.degree. C., 70.degree. C.,
80.degree. C., 90.degree. C., 100.degree. C., or even above
150.degree. C., depending on the nature of the polymer in the
plastic composition. Typically, this temperature does not exceed
300.degree. C. More particularly, the temperature does not exceed
250.degree. C. The temperature of the step (b) can be adapted by a
person skilled in the art depending on the type of the plastic
composition and the polymer it comprises, and/or the kind of
plastic articles intended. Particularly, the temperature is chosen
according to the melting point, or melting temperature of the
polymer of the plastic composition produced from step (a).
[0231] In a particular embodiment, step (b) is performed at the
melting point of the polymer of the plastic composition. The
polymer is then in a partially or totally molten state. In another
embodiment, step (b) is performed at a temperature between the
glass transition temperature (Tg) and the melting point of said
polymer. In another particular embodiment, step (b) is performed at
a temperature above the melting point of said polymer.
[0232] Typically, said step (b) may be carried out by extrusion,
extrusion-compounding, extrusion blow-molding, blown film
extrusion, cast film extrusion, calendering and thermoforming,
injection-molding, compression molding, extrusion-swelling, rotary
molding, ironing, coating, stratification, expansion, pultrusion,
compression-granulation, or 3D printing. Such operations are well
known by the person skilled in the art, who will easily adapt the
process conditions according to the kind of plastic articles
intended (e.g., temperature, residence time, etc.). As an example,
blown-film or cast film extrusion is particularly suited for the
production of plastic films. As another example, calendering
process is particularly suited for the production of plastic
sheets, and injection-molding, thermoforming, blow molding,
rotomolding or 3D printing are particularly suited for the
production of plastic rigid articles.
[0233] In a preferred embodiment, step (b) is implemented with a
solid plastic composition under a powder or granulated form,
preferably under a granulated form.
[0234] The plastic article comprises between 0.1% and 10% by weight
of the plastic composition, based on the total weight of the
plastic article. Preferably, the composition represents between
0.1% and 5%, more preferably between 0.1% and 3% of the plastic
article. Alternatively, the plastic composition represents about 5%
of the plastic article.
[0235] In another embodiment, the liquid composition of the
invention is directly introduced in the step (b) of shaping the
plastic article.
[0236] In a particular embodiment, the present invention relates to
a process for preparing a plastic article, comprising: [0237] a
step (a) of mixing between 0.1% to 10% by weight of the composition
as described above with at least PLA, wherein the biological
entities of the composition are selected from proteases having a
PLA-degrading activity and, [0238] a step (b) of shaping said
mixture of step (a) in a plastic article,
[0239] wherein the step (a) of mixing is preferably performed at a
temperature between 150 and 180.degree. C. and/or in an extruder,
preferably a twin-screw extruder, and more preferably a co-rotative
twin-screw extruder.
[0240] More generally, the plastic articles may be produced by any
techniques known by a person skilled in the art using the liquid
composition of the invention.
[0241] Advantageously, the plastic article of the invention
comprises, based on the total weigh of the plastic article: [0242]
from 10 to 98% of a polyester as defined above, particularly
polylactic acid (PLA), [0243] from 0.01 to 10% of a polysaccharide
carrier, selected from starch derivatives, natural gums, marine
extracts, microbial and animal polysaccharides as defined above,
[0244] from 0 to 30% of a first polymer having a melting
temperature below 140.degree. C. and/or a glass transition
temperature below 70.degree. C., as defined above and [0245] from
0.01 to 10% of biological entities having a PLA-degrading
activity.
[0246] Preferably the plastic article comprises at least 3% of a
first polymer, more preferably at least 4% of a first polymer. In
another preferred embodiment, the plastic article comprises from
0.1% to 1% of polysaccharide carrier. In another preferred
embodiment, the plastic article comprises PLA as main component and
less than 1% of biological entities having a PLA-degrading
activity, preferably less than 0.5%, preferably about 0.25%. In
another particular embodiment, the plastic article comprises from
0.1 to 0.5% of enzymes having a PLA-degrading activity, preferably
about 0.25%.
Plastic Article with Homogenous Dispersion of Biological
Entities
[0247] It is also another object of the invention to provide a
method for homogenizing the dispersion of polymer-degrading
biological entities in a plastic article comprising at least one
polymer and said biological entities, said method comprising
introducing during the process of production of such plastic
article, the liquid composition as described above.
[0248] It is thus another object of the invention to provide a
plastic article comprising at least one polymer and the composition
as described above, wherein the biological entities of the
composition are able to degrade said polymer and are homogenously
dispersed in the plastic article.
[0249] The inventors have discovered that producing plastic article
with the composition of the invention lead to plastic article with
an increased homogeneity of the dispersion of biological entities
in the plastic article compared to plastic article produced with
biological entities under a solid form, thus leading to a plastic
article with enhanced physical properties. The inventors have also
discovered that the choice of the carrier is of importance in order
to protect the biological entities during the production process
and lead to plastic articles with expected degradation and
technical performance.
[0250] The inventors have shown that it is possible to improve the
degradability and the physical and/or mechanical characteristics of
plastic articles comprising polymer and biological entities having
a polymer-degrading activity by the use of the liquid composition
of the invention during the production process of the plastic
article, compared to the use of a solid or liquid composition of
biological entities of the art.
[0251] It is thus another object of the invention to provide a
method for homogenizing the dispersion of the biological entities
in a plastic article, said method comprising introducing during the
process of production of the plastic article, the liquid
composition of the invention.
[0252] The homogeneity of the dispersion of biological entities in
the plastic article may be evaluated by the one skilled in the art,
according to methods known per se in the art. For instance, and
within the context of the invention, the homogeneity of the
dispersion of biological entities in the plastic article may be
assessed by the measurement of at least one of the following
properties: Haze, surface roughness, dynamic friction coefficient,
Young's modulus, elongation at break, tensile stress at break,
maximum stress, strain at maximum stress, impact strength and
biodegradability.
[0253] Haze is defined as the percentage of incident light
scattered by more than 2.5.degree. through the plastic article.
Haze is caused by impurities contained in the plastic article (such
as accumulation of tiny particles in the article or very small
defects on the surface) or its level of crystallinity. The lower
the Haze value, the higher the clarity of the article is. Haze has
no specific unit, it is expressed in %. If Haze value is greater
than 30%, the article is diffusing. Hazemeters and
spectrophotometers may be used to measure the level of Haze. Haze
of plastic articles may be measured according to ASTM D1003 or NF
EN 2155-9. According to the invention, the Haze of the article is
measured according to NF EN 2155-9 (August 1989). Particularly, the
plastic article produced from a liquid composition of biological
entities may exhibit a lower Haze value than the same plastic
article produced from a solid composition of biological entities of
the art. Typically, the plastic article shows a Haze value reduced
of about 1%, 2%, 3%, 4%, 5% or more, as compared to the Haze value
of a plastic article produced with a solid or liquid composition of
biological entities of the art.
[0254] Elongation at break or strain at break of the plastic
article is related to the ability of a plastic article to resist
changes of shape without cracking. Elongation at break is also
known as fracture strain or tensile elongation at break. It is
measured in % and can be calculated by dividing the extension at
break of the plastic article by the initial gage length of the
plastic article and multiplying by 100.
[0255] Tensile stress at break also known as tensile strength at
break or as stress at break of the plastic article is defined as
the tensile stress at which the test specimen ruptures. Tensile
stress also known as ultimate tensile stress or maximum stress
corresponds to the maximum tensile stress sustained by the test
specimen during tensile test. It is calculated by dividing the
maximum load by the original minimum cross sectional area of the
specimen. The result shall be expressed in force per unit area,
usually megapascals (MPa).
[0256] Strain at maximum stress or tensile strain at tensile
strength is the tensile strain at the point corresponding to the
tensile strength. It is measured in % and can be calculated by
dividing the extension at maximum stress of the plastic article by
the initial gage length of the plastic article and multiplying by
100.
[0257] Young's modulus of the plastic article, also known as the
elastic modulus or tensile modulus, is a measure of the stiffness
of a solid material. It is a mechanical property of linear elastic
solid materials. It defines the relationship between stress (force
per unit area) and strain (proportional deformation) in a material.
The result shall be expressed in pascal or megapascals (MPa).
[0258] Young's modulus, elongation at break, tensile stress at
break, maximum stress, strain at maximum stress, of plastic
articles may be measured according to ASTM D882-12 or NF EN ISO
527-3 for plastic article with a thickness below 1 mm. It may
particularly be measured in two different directions: machine
direction or transverse direction. Determination of these criteria
for plastic articles with a thickness from 1 mm to 14 mm is done
with ASTM D638-14 or NF EN ISO 527-2.
[0259] Elongation at break, tensile stress at break (or ultimate
tensile strength), maximum stress, strain at maximum stress, and
Young modulus of plastic articles may be measured according to ASTM
D882-12 or NF EN ISO 527-3 for plastic article with a thickness
below 1 mm. It may be measured in two different directions: machine
direction or transverse direction with the following parameters
(rate of grip separation for Young's modulus: 10 mm/min, rate of
grip separation for other properties: 50 mm/min, initial grip
separation 100 mm, plastic article dimension: length 150 mm; width
15 mm; average thickness 17 .mu.m) or others conditions as stated
in the standards. Determination of these criteria for plastic
articles with a thickness from 1 mm to 14 mm is done with ASTM
D638-14 or NF EN ISO 527-2.
[0260] Particularly, the plastic article, obtained by use of a
liquid composition as exposed above may exhibit a higher elongation
at break than the same plastic article produced from a solid
composition of biological entities. Typically, the plastic article
shows an elongation at break, in at least one direction selected
from machine direction or transverse direction, 10% higher,
preferably 20%, 50%, 100% higher, or more, than the elongation at
break of a plastic article produced with a solid composition of
biological entities.
[0261] Particularly, the plastic article produced with a liquid
composition of the invention may exhibit a higher tensile stress at
break than the same plastic article produced from a solid
composition of biological entities. Typically, the plastic article
shows a tensile stress at break 20% higher, preferably 30%, 40%,
50% higher, or more, than the tensile stress at break of a plastic
article produced with a solid composition of biological entities.
Typically, the plastic article shows a tensile stress at break 5
MPa higher, preferably 7 MPa, 10 MPa, 15 MPa higher, or more, than
the tensile stress at break of a plastic article produced from a
solid composition of biological entities, in at least one direction
selected from machine direction or transverse direction.
[0262] Particularly, the plastic article produced from a liquid
composition of the invention may exhibit a higher Young modulus
than the same plastic article produced from a solid composition of
biological entities. Typically, the plastic article shows a Young
modulus of about 20% higher, preferably 30%, 40%, 50% higher, or
more, than the Young modulus of a plastic article produced from a
solid composition of biological entities, in at least one direction
selected from machine direction or transverse direction. Typically,
the plastic article shows a Young modulus of about 20 MPa higher,
preferably 30 MPa, 50 MPa, 100 MPa higher, or more, than the Young
modulus of a plastic article produced from a solid composition of
biological entities, in at least one direction selected from
machine direction or transverse direction.
[0263] Dynamic friction coefficient or sliding friction coefficient
or coefficient of kinetic friction (also abbreviated as .mu..sub.D)
occurs when two objects are moving relative to each other and rub
together (like a mass on the ground). According to the invention,
.mu..sub.D is measured when a plastic article is sliding over
another same plastic article. The sliding friction coefficient is
defined as the ratio of the dynamic frictional force face by the
plastic article (force needed to overcome friction) to the normal
force N acting perpendicular to both plastic articles. The
coefficient has no unit. The surfaces to be tested are placed in
planar contact and under uniform contact pressure (normal force N).
The force required to move the surfaces relative to each other is
recorded (dynamic frictional force). According to the invention,
.mu..sub.D is measured according to standard NF EN ISO-8295
(December 2004) which fits for plastic film or plastic sheet with a
thickness below 0.5 mm. The apparatus comprises a horizontal test
table on which is placed the plastic article, a mass generating the
press force (1.96 N) and to which the plastic article is attached,
and a traction mechanism for producing a relative movement between
the mass and test table. According to the invention, the mass is
pulled and moved on the test table (test speed=500 mm/min). The
measure is precise about 0.01%. Particularly, the plastic article
produced from a liquid composition of biological entities may
exhibit a lower dynamic friction coefficient than the same plastic
article produced from a solid composition of biological entities.
Typically, the plastic article shows a dynamic friction coefficient
5% lower, preferably 10%, 15%, 20% lower, or more, than the dynamic
friction coefficient of a plastic article produced from a solid
composition of biological entities.
[0264] Surface roughness of the plastic article may be assessed by
a visual test of a panel of users. The plastic article shows no
visible defects on its surface, it is smooth. The plastic article
produced from a solid composition shows irregularity on the surface
due to particles aggregates that we can feel by touch and visible
to the naked eye. This is also assessed by the measurement of the
thickness using a Mitutoyo thickness gauge to demonstrate the
presence of aggregates in the plastic article.
[0265] Impact strength is defined as the resistance of a material
to fracture under stress applied at high speed, defined by the
amount of energy absorbed before fracture. For rigid plastic
article, impact strength may be measured according to standard NF
EN ISO 179 using plastic specimens produced with the same material
of such plastic article and having thickness of 4 mm and a total
length of 80 mm. Determination of impact strength for rigid plastic
article with a thickness below 4 mm may also be measured directly
on such plastic article according to standard NF EN ISO 6603-1.
Particularly, the plastic article obtained by the use of a liquid
composition of biological entities of the invention may exhibit a
higher impact strength than the same plastic article produced from
a solid composition of biological entities. Typically, the plastic
article of the invention shows an impact strength of about 20%
higher, preferably 25%, 30%, 40% higher than the impact strength of
a plastic article produced from a solid composition of biological
entities.
[0266] The inventors have also shown that the introduction of
biological entities by way of the liquid composition of the
invention during the production process of a plastic article does
not impact the technical performances of such plastic articles
compared to plastic articles containing no biological entities.
[0267] The invention also provides a method for increasing the
biodegradability of a plastic article comprising at least one
polymer, said method comprising introducing during the process of
production of the plastic article, the liquid composition of the
invention.
[0268] Biodegradability of the plastic article is defined as the
liberation of monomers, dimers, or water and carbon dioxide over a
defined period of time under aqueous conditions. Particularly,
according to the invention, the biodegradability of a plastic
article containing PLA is measured according to the release of
lactic acid and dimer of lactic acid. Particularly, the plastic
article obtained by the use of a liquid composition of the
invention may exhibit a higher biodegradability than the same
plastic article produced from a solid or liquid composition of
biological entities of the art. Typically, the plastic article of
the invention shows a biodegradability of about 25%, 30%, 40%, or
100% higher than the biodegradability of a plastic article produced
from a solid or liquid composition of biological entities of the
art after 2 days.
[0269] In a particular embodiment, the plastic article is a plastic
film, comprising at least one polyester and biological entities
able to degrade said polyester.
[0270] Alternatively or in addition, the plastic film of the
invention is a film with a thickness below 100 .mu.m, preferably
below 50 .mu.m, more preferably below 30 .mu.m, even more
preferably below 20 .mu.m.
[0271] Particularly, the plastic film produced from the composition
of the invention shows a lower Haze value of about 3%, 4%, 5% or
more, as compared to the Haze value of a plastic film produced from
a solid composition of biological entities. Accordingly, the
plastic film Haze value is comprised between 80% and 95%,
preferably between 85% and 93%. Alternatively, the plastic film
Haze value is above 30%, preferably above 50%, more preferably
above 70%, even more preferably above 85%. Otherwise, the plastic
film Haze value is below 98%, preferably below 96%, more preferably
below 95%, even more preferably below 94%. In another embodiment,
the plastic film Haze value is below 60%.
[0272] In another particular embodiment, the film's Young's modulus
is preferably above 200 MPa in both directions (machine or
transverse), and/or the film's tensile stress at break is
preferably above 15 MPa in both directions (machine or transverse),
and/or the film's elongation at break is preferably above 130% in
machine direction and above 300% in transverse direction. In
another particular embodiment, the film according to the invention
has an elongation at break greater than 130%, in longitudinal
direction and greater than 240% crosswise, measured according to EN
ISO 527-3, and/or a tear strength greater than 30 N/mm in the
transverse direction of the film, measured according to EN ISO
6383-1 and this while having a high PLA content. It also has an
elastic modulus greater than 200 MPa in the longitudinal direction
and greater than 150 MPa transverse, measured according to EN ISO
527-3 and/or a maximum stress greater than 15 MPa in longitudinal
direction and greater than 13 MPa in transverse direction, measured
according to EN ISO 527-3.
[0273] In another particular embodiment, the plastic article is a
rigid plastic article, comprising at least one polyester and
biological entities having a polyester degrading activity.
[0274] In a particular embodiment, the rigid plastic article of the
invention shows an impact strength above 17 kJ/m2, preferably above
20 kJ/m2 according to NF EN ISO 179.
[0275] In another particular embodiment, the rigid plastic article
of the invention shows, according to NF EN ISO 527-2, a tensile
modulus below 4 GPa, preferably below 3 GPa, and the tensile
strength at break is above 40 MPa, preferably above 55 MPa.
[0276] According to a particular embodiment, the rigid plastic
article of the invention is a sheet with a thickness below 800
.mu.m, preferably below 450 .mu.m. The sheet of the invention shows
an impact strength above 1 J, preferably above 1.5 J, more
preferably above 2 J, according to NF EN ISO 7765-1. The elastic
modulus of the sheet is below 2 GPa in both direction (machine and
transverse) while maintaining enough stiffness for the intended
application, and the strain at maximum stress of the sheet is above
3%, preferably above 4% in both direction.
[0277] In another particular embodiment, the plastic article is a
non-woven fabric, comprising at least one polyester and biological
entities having a polyester degrading activity.
[0278] Advantageously, the resulting plastic article is a
biodegradable plastic article complying with at least one of the
relevant standards and/or labels known by a person skilled in the
art such as standard EN 13432, standard NFT51800, standard ASTM
D6400, OK Biodegradation Soil (Label TUV Austria), OK
Biodegradation Water (Label TUV Austria), OK Compost (Label TUV
Austria), OK Compost Home (Label TUV Austria).
[0279] A biodegradable plastic article refers to a plastic that is
at least partially transformed under environmental conditions into
oligomers and/or monomers of at least one polyester of the plastic
article, water, carbon dioxide or methane and biomass. For
instance, the plastic article is biodegradable in water.
Preferably, about 90% by weight of the plastic article is
biodegraded in water within less than 90 days, more preferably
within less than 60 days, even more preferably within less than 30
days. More preferably, the plastic article may be biodegraded when
exposed to wet and temperature conditions that occur in
environment. Preferably, about 90% by weight of the plastic article
is biodegraded with less than 3 years in the environment, more
preferably within less than 2 years, even more preferably within
less than 1 year. Alternatively, the plastic article may be
biodegraded under industrial composting conditions, wherein the
temperature is maintained above 50.degree. C.
EXAMPLES
Example 1--Preparation of Liquid Compositions of the Invention, and
Uses Thereof for the Manufacture of Films Comprising PCL and
PLA
1.1--Preparation of Liquid Compositions of the Invention
[0280] Different liquid compositions have been prepared using a
commercial protease, Savinase.RTM. 16L (Novozymes) sold under a
liquid form (containing more than 50% by weight of polyols based on
the total weight of the liquid composition and water). Such enzyme
is known for its ability to degrade polylactic acid (Degradation of
Polylactide by commercial proteases; Y. Oda, A. Yonetsu, T. Urakami
and K. Tonomura; 2000).
[0281] Liquid composition A (LC-A) has been obtained by
ultrafiltration and diafiltration of the commercial Savinase.RTM.
16L on 3.5 Kd membrane (diafiltration factor about 50) using
CaCl.sub.2) 5 mM. Such process enables polyols contained in the
commercial Savinase.RTM. to be removed. As no carrier has been
added in liquid composition A, this composition corresponds to the
negative control.
[0282] Liquid Composition B and C (LC-B and LC-C) were also
obtained from the commercial liquid form of Savinase.RTM. by
ultrafiltration and diafiltration on 3.5 Kd membrane using
CaCl.sub.2) 5 mM (diafiltration factor about 50). Respectively,
maltodextrin (Maldex--TEREOS) and arabic gum (INSTANT GUM
AA--NEXIRA), were added under powder form in the filtrate at same
percentage, at about 23% by weight based on the total weight of the
liquid composition, in order to compare the protective effect of
these two carriers. Description of the different liquid
compositions is resumed in the Table 1.
TABLE-US-00001 TABLE 1 Description of liquid compositions of the
invention (LC-B and LC-C) and a negative control (LC-A). LC-A
Without Carrier LC-B LC-C (negative control) (Maltodextrin) (Arabic
Gum) Carrier 0.0% 23.2% 23.1% Biological Entities 31.4% 23.3% 23.3%
Aqueous 67.0% 52.3% 52.1% solvent (water) Others 1.6% 1.2% 1.5%
(polyols, salts) Total 100% 100% 100% % are given by weight, based
on the total weight of the final liquid composition
1.2--Preparation of a Masterbatch Using the Composition of the
Invention
[0283] Masterbatch compositions have been prepared from pellets of
polycaprolactone (PCL) polymer (Capa.TM. 6500 from Perstorp) and
compositions of the invention described in Example 1.1. Enzyme
activity of said masterbatch has been further determined.
[0284] A compounding machine, or co-rotating twin-screw extruder,
has been used (Leistritz ZSE 18MAXX). This compounding machine
comprised nine successive heating zones Z1 to Z9, wherein the
temperature may be independently controlled and regulated. An
additional zone Z10 was present after zone Z9, corresponding to the
head of the twin-screw (Z10) which is also a heated part. A suited
screw profile was used in order to mix efficiently the liquid
composition of the invention with the melt polymer. Parameters used
for each extruded masterbatch are summarized in Table 2.
[0285] The molten polymer arrived in the screw Z10 comprising a die
plate with one hole of 3.5 mm and was immediately immersed in a 2 m
long cold water bath filled with a mix of water and crushed ice.
The resulting extrudate was granulated into solid pellets <3
mm.
[0286] According to this experiment, 80% by weight of the PCL have
been extruded with 20% by weight of the liquid composition.
TABLE-US-00002 TABLE 2 Temperature profile and process parameters
of the compounding process Polymer Liquid composition Speed
Temperature Flow Flow screw Masterbatch profile (.degree. C.)
Introduction rate Introduction rate Rate Composition Z1 to Z10 Zone
(kg/h) Zone (kg/h) (rpm) MB1 PCL/LC- 70-70-70-70- Z2 2.6 Z0 0.66
150 (negative A 70-65-65-65- control) (80/20) 65-65 MB2 PCL/LC-
70-70-70-70- Z2 2.8 Z0 0.7 175 B 70-65-65-65- (80/20) 65-65 MB3
PCL/LC- 70-70-70-70- Z2 2.4 Z0 0.6 150 C 70-65-65-65- (80/20)
65-65
[0287] The enzyme activity in the masterbatches was determined
according to the protocol described below.
[0288] 50 mg of pellets were mixed with 10 mL of dichloromethane
(Sigma Aldrich, CAS 75-09-2) in a 50 mL Falcon tube. Solution was
mixed using a vortex (Genie2-Scientific Industrie) until the
compound is totally dissolved. Then, 5 mL of 0.1 M Tris buffer pH
9.5 were added. Each tube was manually shaked in order to create an
emulsion. Organic and aqueous phase were then separated by
centrifugation at 10000G during 5 min (Heraeus Multifuge
X302-Thermoscientific). Aqueous phase was removed and kept
separately. Another 5 mL of 0.1 M Tris buffer pH 9.5 was added to
the organic phase and protocol was repeated until removing aqueous
phase. Both 5 mL of aqueous phase are mixed. To remove trace of
dichloromethane in the 10 mL of aqueous phase, oxygen was bubbled
in the sample during 20 minutes. Protease activity of each sample
was determined using colorimetric test: 20 .mu.L of sample at the
right dilution was mixed with 180 .mu.L of a 5 mM pNA solution
(N-succinyl-Ala-Ala-Ala-p-Nitroanilide, Sigma Aldrich--CAS
52299-14-6). Optical density was measured at 30.degree. C.-420 nm
using absorption spectrophotometer (Clariostar-BMG Labtech). Mass
of active enzyme was thus determined using a calibration curve.
[0289] Comparing mass of active enzyme and theoretical enzyme mass
in the compound enabled the percentage of residual activity in the
masterbatches to be determined.
[0290] Residual activities of the masterbatches produced are
resumed in the Table 3.
TABLE-US-00003 TABLE 3 Residual activities of masterbatches
containing liquid composition of the invention MB1 (negative MB2
MB3 control) (maltodextrin) (Arabic gum) PCL/LC-A PCL/LC-B PCL/LC-C
Residual Activity (%) 8% 32% 78%
[0291] Masterbatches produced with the liquid compositions of the
invention (LC-B and LC-C) demonstrate a higher residual activity
compared to the masterbatch produced with a liquid composition
containing no carrier (LC-A--negative control), indicating a higher
protection of the enzyme during the extrusion process. Masterbatch
produced with the composition of the invention comprising arabic
gum show an even better residual activity than the masterbatch
produced with the composition of the invention comprising
maltodextrin.
1.3--Manufacture of Biodegradable Plastic Films
[0292] The granulated masterbatch compositions of Example 1.2 were
used to produce biodegradable polylactic acid-based plastic
articles through an extrusion process. The biodegradability of said
plastic articles was further tested.
Preparation of the PLA-Based Matrix
[0293] The PLA-based matrix was extruded using the twin screw
extruder described in Example 1.2. Composition of this matrix is
42.3% by weight of PLA 4043D by NatureWorks, 51.7% by weight of
PBAT PBE006 by NaturePlast and 6% by weight of CaCO.sub.3 by
OMYA.
[0294] All materials have been dried before extrusion. PLA and PBAT
were dried about 16 hours in a desiccator at 60 and 40.degree. C.
respectively. Vacuum oven at 40.degree. C.-40 mb for 16 h was used
for calcium carbonate.
[0295] Temperature was set at 185.degree. C. in the ten zones of
the extruder. The speed screw rate was 175 rpm, and total input
mass rate was about 7 kg/h. CaCO.sub.3 was introduced in zone 7 to
the melted polymers using a gravimetric feeder to obtain the
matrix. The resulting extrudate was cooled in a cold-water bath
before pelletization.
[0296] Masterbatches: Masterbatches MB1-MB2-MB3 described in
Example 1.2 were used to produce the plastic films.
Film Blowing Step
[0297] Before film blowing extrusion, masterbatches and PLA-based
matrix were dried in desiccator for 40 h at 50.degree. C. Blends
were prepared in order to introduce the same quantity of enzyme in
all the films, based on theoretical enzyme mass in the masterbatch
according to Table 4:
TABLE-US-00004 TABLE 4 composition of manufactured films Film
PLA-based MB1 (negative control) MB2 MB3 reference Matrix PCL/LC-A
PCL/LC-B PCL/LC-C Film A 97% 3% -- -- Film B 95% -- 5% -- Film C
95% -- -- 5%
[0298] A LabTech compact film blowing Line type LF-250 with 20 mm
30 L/D extruder Type LBE20-30/C was used to produce films. The
screw speed rate was 50 rpm. Set temperatures are detailed in Table
5.
TABLE-US-00005 TABLE 5 Extruder and die temperature settings Zone
Z1 Z2 Z3 Z4 Die #1 Die #2 T.degree. C. 150.degree. C. 150.degree.
C. 150.degree. C. 150.degree. C. 155.degree. C. 155.degree. C.
1.4--Tests of Depolymerization
[0299] Tests of depolymerization have been performed, using plastic
films produced in Example 1.3 according to the protocol set
below.
[0300] 100 mg of each film were weighted and introduced in a
plastic bottle containing 50 mL of 0.1 M Tris buffer pH 8. The
depolymerization was started by incubating each sample at
28.degree. C., 150 rpm in a Infors HT Multitron Pro incubation
shaker. Aliquots of 1 mL of buffer were sampled regularly and
filtered on 0.22 .mu.m syringe filter, samples were analyzed by
High Performance Liquid Chromatography (HPLC) with an Aminex
HPX-87H column to monitor the liberation of lactic acid (LA) and
lactic acid dimer. Chromatography system used was an Ultimate 3000
UHPLC system (Thermo Fisher Scientific, Inc. Waltham, Mass., USA)
including a pump module, an autosampler, a column oven thermostated
at 50.degree. C., and an UV detector at 220 nm. Eluent was 5 mM
H.sub.2SO.sub.4. Injection was 20 .mu.L of sample. LA was measured
according to standard curves prepared from commercial LA.
[0301] Hydrolysis of plastic films was calculated based on LA and
dimer of LA released. Percentage of degradation is calculated
regarding the percentage of PLA in the films.
[0302] Results of the depolymerization of the films, after 2 days,
are shown in Table 6.
TABLE-US-00006 TABLE 6 Comparison of the depolymerization of the
film produced with the composition of the invention (B and C) and a
negative control Depolymerization rate after 2 days Film A
(negative control)-Comprising 0.002% MB1 (PCL/LC-A) Film
B-Comprising MB2 9.6% (PCL/LC-B-Maltodextrin) Film C-Comprising MB3
11.6% (PCL/LC-C-Arabic Gum)
[0303] Films produced with the compositions of the invention
(MB2/LC-B and MB3/LC-C) show a higher depolymerization rate, due to
a higher residual activity as compared to the control film produced
with a liquid composition deprived of carrier (MB1/LC-A--negative
control). These results confirm that the use of the liquid
composition of the invention leads to a higher protection of the
enzyme during the extrusion process. Film produced with the
composition comprising arabic gum shows an even better
degradability than the film produced with the composition
comprising maltodextrin.
Example 2--Preparation of a Liquid Composition of the Invention,
Use of Such Composition for the Production of Films and Assessment
of the Mechanical and Degradation Properties of the Films
2.1--Preparation of Compositions Comprising Biological Entities
[0304] A liquid composition ("LC") has been prepared from the
commercial protease, Savinase.RTM. 16L (Novozymes).
[0305] LC has been obtained by ultrafiltration and diafiltration of
the commercial Savinase.RTM. 16L (diafiltration factor about 100)
on 3.5 Kd membrane using CaCl.sub.2 5 mM to obtain a concentrated
liquid composition and to remove polyols present in the commercial
solution. About 23% of arabic gum (INSTANT GUM AA--NEXIRA), based
on the total weight of the liquid composition, was then added as a
carrier in the liquid composition.
[0306] A solid composition was also prepared according to the same
protocol using a commercial protease, Savinase.RTM. 16L and the
protocol set above. The liquid composition obtained was
concentrated, and was then dried by freeze drying to obtain a solid
composition called "SC".
[0307] Comparisons of the different compositions are summarized in
Table 7.
TABLE-US-00007 TABLE 7 Liquid and solid compositions Liquid Solid
Enzyme composition composition (LC) composition (SC) Aqueous
solvent (water) 51.3% 0.5% Carrier (arabic gum) 23.3% 15.7%
Biological entities 23.0% 33% Other components including 2.4% 50.8%
polyols (glycerol, propylene glycol) and other additives % are
given by weight, based on the total weight of the final
composition
2.2--Preparation of Masterbatches
[0308] Masterbatches have been prepared with pellets of
polycaprolactone polymer (PCL--Capa.TM. 6500 from Perstorp) and the
liquid or solid compositions of 2.1, using the same compounding
machine as in Example 1.2.
[0309] More particularly, a masterbatch comprising PCL and the
liquid enzyme composition LC from Example 2.1 was produced. The PCL
and LC were introduced separately in the extruder at the feeding
zone which is a non-heated zone. For feeding, a gravimetric feeder
was used for the polymer and a peristaltic pump for the liquid
composition. The obtained masterbatch was called MB-L.
[0310] In parallel, a masterbatch comprising PCL and the solid
enzyme composition SC from Example 2.1 was produced. SC was
introduced in Zone 7 using a gravimetric feeder suited for dosing
solid in powder from. The obtained masterbatch was designated
"MB-S".
[0311] Parameters used for masterbatch extrusion are detailed in
table 8 and table 9. A suited screw profile was used in order to
mix efficiently the corresponding compositions with the
polymer.
TABLE-US-00008 TABLE 8 Extruder temperature settings Z10 Zone Z1 Z2
Z3 Z4 Z5 Z6 Z7 Z8 Z9 (die) MB-L Temperature 70 70 70 70 70 65 65 65
65 65 (.degree. C.) MB-S Temperature 70 70 70 70 70 70 70 70 70 70
(.degree. C.)
TABLE-US-00009 TABLE 9 Extrusion parameters used for masterbatches
Screw speed Total input Composition rate (rpm) flow rate (kg/h)
MB-L 72% Capa .TM. 6500 + 28% LC 150 3 MB-S 70% Capa .TM. 6500 +
30% SC 150 3.5
[0312] The molten polymer arrived in the screw Z10 comprising a die
plate with one hole of 3.5 mm and was immediately immersed in a 2 m
long cold-water bath filled with a mix of water and crushed ice.
The resulting extrudate was granulated into solid pellets <3
mm.
2.3--Production of Films
A--Preparation of the PLA-Based Matrix
[0313] Three different PLA-based matrixes were used for the
production of the films: two commercial compounds Ecovio.RTM. F2332
and Ecovio.RTM. F2223 from BASF, and a Home compounded matrix
called "Matrix 1".
[0314] Matrix 1 was manufactured using a twin-screw extruder
CLEXTRAL EV25HT comprising twelve zones Z1 to Z12, wherein the
temperature is independently controlled and regulated. Matrix 1 is
composed of 33% of pre-plasticized PLA containing 10% by weight of
tributyl acetyl citrate (CITROFOL.RTM. BII from Jungbunzlauer), 32%
of PBAT Ecoflex C1200 supplied by BASF, 30% of thermoplastic starch
where the starch is standard maize starch 171111 supplied by
Roquette and 5% of calcium carbonate from OMYA.
TABLE-US-00010 TABLE 10 Extruder temperature settings Zone Z1 Z2 Z3
Z4 Z5 Z6 Z7 Z8 Z9 Z10 Z11 Z12 Matrix Temperature 50 70 70 80 90 150
150 150 150 150 150 150 1 (.degree. C.)
B--Production of the Films with Liquid Composition (MB-L)
[0315] For film blowing, a LabTech compact film blowing Line type
LF-250 with 20 mm 30 L/D extruder Type LBE20-30/C was used. The
screw speed rate used was 60 rpm. Blow ratio of film was about 5
for an objective of 17 .mu.m.
[0316] Before film blowing, the MB-L (example 2.2) and the
different PLA-based matrix were dried in a desiccator for 40 h at
50.degree. C. Then MB-L was mixed to the PLA-based matrix with a
weight ratio PLA to masterbatch of 93/7.
[0317] Films obtained with PLA-based matrix Ecovio.RTM. F2332 and
Ecovio.RTM. F2223 were designated as Film 1 and Film 2
respectively, and Table 11 shows the parameters used for
extrusion.
TABLE-US-00011 TABLE 11 Extruder and die temperature settings Film
Zone Z1 Z2 Z3 Z4 Die #1 Die #2 Film 1 (ecovio .RTM. F2332)
T.degree. C. 145 150 150 150 155 155 Film 2 (ecovio .RTM. F2223)
T.degree. C. 150 151 151 153 155 157
[0318] Film produced with Matrix 1 was designated as Film 3 and
Table 12 shows the parameters used for extrusion.
TABLE-US-00012 TABLE 12 Extruder and die temperature settings
Sample Zone Z1 Z2 Z3 Z4 Die #1 Die #2 Film 3 (Matrix 1) T.degree.
C. 145 147 148 148 148 150
C--Production of the Control Films with Solid Composition
(MB-S)
[0319] PLA-based matrix Ecovio.RTM. F2332 and Ecovio.RTM. F2223 and
the Matrix 1 were used as PLA-based matrix to produce films with
the masterbatch comprising the solid composition of biological
entities and were respectively designated as Film 4, Film 5 and
Film 6.
[0320] Before film blowing, the MB-S and PLA-based matrix were
dried in a desiccator for 40 h at 50.degree. C. An additional
masterbatch comprising only PCL and arabic gum 70/30 w/w was added
to the mixture MB-S/PLA-based matrix in order to obtain the same
biological entities concentration in all the films of the
invention.
[0321] Finally, the films were made by use of 93% by weight of a
PLA-based matrix and 7% by weight of a mixture of both
masterbatches (MB-S and additional masterbatch).
[0322] Then MB-S was dry-mixed to the PLA-based matrix and
introduced in the film blowing extruder.
[0323] The same process as for films 1, 2 and 3 was used to produce
the films, except the temperature profile as shown in table 13:
TABLE-US-00013 TABLE 13 Extruder and die temperature settings Film
Zone Z1 Z2 Z3 Z4 Die #1 Die #2 Films 4, 5 and 6 T.degree. C. 135
147 147 150 152 150
[0324] Films 1 and 4, Films 2 and 5, and Films 3 and 6 respectively
have same compositions, except the nature of the masterbatch (solid
vs. liquid).
2.4--Evaluation of Mechanical Properties and Degradation Properties
of the Plastic Films
[0325] The films produced in example 2.3 were analyzed for the
following parameters:
[0326] A. Haze
[0327] Haze is determined using a spectrometer UV-Visible Perkin
Elmer 650S equipped with a 150 mm integrating sphere according to
NF EN 2155-9 (August 1989). The values are determined on a
50.times.30 mm.sup.2 sample. On each film, the measurements are
repeated 3 times on 3 different parts of the film.
[0328] B. Surface Roughness (Dynamic Friction Coefficient)
[0329] The dynamic friction coefficient (.mu..sub.D) is measured
according to standard NF EN ISO-8295 (December 2004) which fits for
plastic film or plastic sheet with a thickness below 0.5 mm. It is
determined using a Lloyd Instruments LS5 testing machine equipped
with a 20 N sensor capacity. The apparatus comprises a horizontal
test table on which the first sample is placed, a mass generating
the press force (1.96 N) and to which the second sample is
attached, and a traction mechanism to produce a relative movement
between the mass and the test table. The mass is pulled and moved
on the test table (test speed=500 mm/min). The measure is precise
about 0.01%. The sample dimensions are the followings: 80
mm.times.200 mm.
[0330] The dynamic friction force F.sub.D is the average force on
the 6 first centimeters of relative movement.
[0331] C. Mechanical Tensile Properties and Thickness
[0332] Tensile mechanical properties (elongation at break, tensile
stress at break, Young's modulus) were determined using a Zwick
testing machine equipped with 50 N sensor capacity according to
ASTM D882-12 standard (at 23.degree. C. and 55% RH). Two film
directions: machine direction and transverse direction were
analyzed with the following parameters: [0333] Rate of grip
separation for Young's modulus=10 mm/min, [0334] Rate of grip
separation for other properties=50 mm/min, [0335] Initial grip
separation: 100 mm, [0336] Sample dimensions: 150 mm.times.15 mm,
[0337] Average thickness: 17 .mu.m.
[0338] Thickness used for tensile analysis was determined based on
the film weights, dimensions and densities. This choice was made to
overcome the overestimations of the thickness due to the presence
of aggregates of particles in the surface of the film especially
when solid compositions are used.
[0339] Nevertheless, measurement of the thickness can be done using
a Mitutoyo thickness gauge to demonstrate the surface roughness
observed for films containing aggregates.
[0340] D. Depolymerization Test
[0341] The protocol was same as the one used in Example 1.4.
[0342] E. Results and Comparison
[0343] The results obtained for the film produced with the liquid
composition of the invention was compared to the results obtained
for the film produced with the solid composition: Film 1 versus
Film 4; Film 2 versus Film 5, and Film 3 versus Film 6.
[0344] Mechanical Properties
[0345] Table 14 shows the Haze results measured on Film 1, 2, 4 and
5. The Haze values of the films 1 and 2 are respectively lower than
the ones of 4 and 5. Haze is caused by impurities contained in the
plastic article (such as accumulation of tiny particles in the
article or very small defects on the surface). The lower the Haze
value, the higher the clarity of the article is. Using a liquid
composition of the invention during the production process of a
plastic article enabled to reduce the Haze of the film in
comparison of using a solid composition of biological entities,
indicating the liquid composition of the invention enable to
increase the dispersion of biological entities in the film.
TABLE-US-00014 TABLE 14 Haze results determined for films produced
from liquid or solid enzyme compositions Characteristic Unit Film 1
Film 4 Film 2 Film 5 ecovio .RTM. ecovio .RTM. ecovio .RTM. ecovio
.RTM. F2332 + F2332 + F2223 + F2223 + Composition MB-L MB-S MB-L
MB-S Haze % 86.6 92.4 85.5 88.1 Base 93.3 100 97 100 100
[0346] Table 15 and 16 show the dynamic friction coefficient,
tensile properties and thickness measured by Mitutoyo thickness
gauge of the films produced in 2.3. "s" corresponds to the standard
deviation in the same unit as the characteristic measured.
TABLE-US-00015 TABLE 15 Dynamic friction coefficient, tensile
properties and thickness of films Test Characteristic direction
Unit Film 1 Film 4 Film 2 Film 5 Film 3 Film 6 Composition ecovio
.RTM. ecovio .RTM. ecovio .RTM. ecovio .RTM. Matrix Matrix 1 +
F2332 + F2332 + F2223 + F2223 + 1 + MB-S MB-L MB-S MB-L MB-S MB-L
Thickness .mu.m 20 55 21 43 25 60 (Mitutoyo) Dynamic MD N 0.352
0.376 0.266 0.357 0.241 0.287 friction s 0.09 0.009 0.007 0.005
0.01 0.007 coefficient Young modulus MD MPa 220 285 992 708 1020
645 s 8 5 59 62 91 66 TD MPa 145 139 297 218 618 394 s 2 6 5 10 82
14 Strain at break MD % 250 210 220 120 140 33 s 21 11 3 8 11 8 TD
% 480 310 200 65 46 12 s 7 6 22 9 10 2 Ultimate tensile MD MPa 23.9
24.1 33.5 16.1 18.1 9.5 strength s 0.9 0.8 1.2 1.3 1 0.6 TD MPa
21.4 15.4 14.7 9.1 13 6 s 1 0.8 1.1 0.3 1.5 0.7
[0347] In Table 16, films produced from MB-S are used as a
reference and considered as 100% of the defined parameter.
TABLE-US-00016 TABLE 16 Dynamic friction coefficient and tensile
properties of films on base 100 Test Characteristic direction Unit
Film 1 Film 4 Film 2 Film 5 Film 3 Film 6 Composition ecovio .RTM.
ecovio .RTM. ecovio .RTM. ecovio .RTM. Matrix 1 + Matrix 1 + F2332
+ F2332 + F2223 + F2223 + MB-L MB-S MB-L MB-S MB-L MB-S Dynamic MD
N 93.6 100 74.5 100 84 100 friction coefficient Young modulus MD
MPa 77 100 140 100 158 100 TD MPa 104 100 136 100 156 100 Strain at
break MD % 119 100 183 100 424 100 TD % 154 100 307 100 383 100
Ultimate tensile MD MPa 99 100 208 100 191 100 strength TD MPa 139
100 161 100 218 100
[0348] Friction coefficient is the ratio between the sliding force
and the holding force of two surfaces in contact. This coefficient
characterizes the difficulty of two materials to slide on each
other. This difficulty can be increased in case of surface
roughness. Dynamic friction coefficient values of the films 1, 2
and 3 are lower than the ones of films 4, 5 and 6 respectively
indicating less surface roughness. Using a liquid composition of
the invention during the production process allows to reduce the
dynamic friction coefficient and by this way to reduce the surface
roughness in comparison of using a solid composition of biological
entities.
[0349] This characteristic was also visible to the naked eye: films
4, 5, 6 show irregularity on the surface due to particles
aggregates.
[0350] Measurement of the thickness using a Mitutoyo thickness
gauge also demonstrates this surface roughness observed for films
produced from solid composition of biological entities leading to
aggregates in the film.
[0351] Young modulus, strain at break and ultimate tensile strength
measured for films are significantly higher with the liquid
composition of the invention compared to the solid composition. The
liquid composition of the invention has smaller particle size that
leads to a fine and homogeneous dispersion of particles in the film
and as consequent to an improvement of mechanical properties.
[0352] Depolymerization Test
[0353] Depolymerization test showed that films obtained from the
liquid composition of the invention have a significantly higher
percentage of depolymerization rate compared to those obtained with
solid enzyme composition, as shown in Table 17 (films from
Ecovio.RTM. F2332), Table 18 (films from Ecovio.RTM. F2223) and
Table 19 (films from Matrix 1). Films produced from MB-S are used
as a reference and their level of depolymerization is considered as
100.
TABLE-US-00017 TABLE 17 Case of ecovio .RTM. F2332-Level of
depolymerisation after 16 days Enzyme Level of composition
depolymerization Film 4 ecovio .RTM. F2332 + MB-S solid 100 Film 1
ecovio .RTM. F2332 + MB-L liquid 775
TABLE-US-00018 TABLE 18 Case of ecovio .RTM. F2223-Level of
depolymerisation after 16 days Enzyme Level of composition
depolymerization Film 5 ecovio .RTM. F2223 + MB-S solid 100 Film 2
ecovio .RTM. F2223 + MB-L liquid 3000
TABLE-US-00019 TABLE 19 Case of Matrix1-Level of depolymerisation
after 2 days Enzyme Level of composition depolymerization Film 6
Matrix 1 + MB-S solid 100 Film 3 Matrix 1 + MB-L liquid 776
2.5--Production of Rigid Plastic Article
[0354] An injection molding machine was used for the production of
rigid plastic articles: KM 50t/380 CX ClassiX type with MC6
computer controller system.
[0355] The rigid plastic articles were produced by incorporation of
the masterbatch MB-L, of Example 2.2 in two types of
polyester-based matrix. The matrixes are chosen from two polylactic
acid polymer grades whose characteristics are shown in Table
20.
TABLE-US-00020 TABLE 20 Characteristics of the polyester-based
matrix used for the production of rigid plastic articles
Polyester-based Specific gravity Melting matrix (g/cm.sup.3) MFI
(g/10 min) temperature (.degree. C.) PLI 003 1.75 35 (190.degree.
C./2.16 155-170 NaturePlast kg) PLA 4043D Ingeo 1.24 6 (210.degree.
C./2.16 145-160 Natureworks kg)
[0356] Before dry-mixing, polyester-based matrix and masterbatch
were dried in desiccator at 50.degree. C. for 40 h, 10% of MB-L was
then added to the polyester-based matrix. Articles with 100%
polyester-based matrix were also produced for comparison.
[0357] A 60 mm.times.60 mm with 1 mm thick pieces were manufactured
by injection molding process. Parameters were set depending on the
grade of polyester-based matrix acid used.
[0358] The parameters set for injection molding are summarized in
Table 21.
TABLE-US-00021 TABLE 21 Extrusion parameters used for production of
rigid articles by injection Set temperatures in barrel zones, from
feed Injection Hold Mold zone to the front zone pressure pressure
Molding temperature Composition (.degree. C.) (bar) (bar) cycle(s)
(.degree. C.) PA1 PLI 003 35/160/160/165/170 1040 1000 41.6 30
(control NaturePlast versus PA2) PA2 PLI 003 35/160/160/165/170
1035 900 43 30 NaturePlast + 10% MB-L PA3 PLA 4043D
35/155/155/160/160 2300 800 32.6 30 (control Ingeo versus
Natureworks PA4) PA4 PLA 4043D 35/155/155/160/160 1900 800 32.6 30
Ingeo Natureworks + 10% MB-L
[0359] Total composition residence time in the barrel was measured
and is about 12 min for PA1 and PA2 and 13 min for PA3 and PA4.
[0360] The rigid articles produced were submitted to a
depolymerization test, according to the protocol described in
Example 1.4. The results are shown in Table 22, PA1 and PA3 are
used as reference and their level of depolymerization is considered
as 100. They demonstrate that the use of the composition of the
invention enables to produce biodegradable rigid plastic
articles.
TABLE-US-00022 TABLE 22 Depolymerization test for the injection
molding plastic articles Sample Level of depolymerization at 10
days PA1 (control) 100 PA2 1500
TABLE-US-00023 TABLE 23 Depolymerization test for the injection
molding plastic articles Sample Level of depolymerization at 10
days PA3 (control) 100 PA4 4267
Example 3--Preparation of a Masterbatch Using a Liquid Composition
of the Invention, Use of Such Masterbatch for the Production of a
PLA-Based Rigid Article and Assessment of the Tensile, Impact and
Degradation Properties of Such Article
3.1--Preparation of a Masterbatch Using a Liquid Composition of the
Invention
[0361] Masterbatches were prepared using pellets of
polycaprolactone (PCL) polymer (Capa.TM. 6500 from Perstorp) and
liquid or solid enzymatic composition described in Table 24. Liquid
composition LC-1 and solid composition SC-1 were prepared with same
manner as detailed in Example 2.1.
TABLE-US-00024 TABLE 24 Enzymatic compositions used for producing
the masterbatches Enzyme Liquid Solid composition composition LC-1
composition SC-1 Aqueous solvent (water) 53.8% 3.2% Dry matter
including 46.2% including 96.8% including Carrier (arabic gum)
22.4% 77.4% Biological entities 19.8% 19.4% Others including 4%
polyols and salts % are given by weight, based on the total weight
of the final composition
[0362] The masterbatch MB-LC1 comprising PCL and the liquid
composition of the invention LC-1 was prepared using a twin-screw
extruder Clextral Evolum 25 HT comprising twelve zones Z1 to Z12,
wherein the temperature is independently controlled and regulated.
The parameters used for the process are the following: temperature
profile 65.degree. C.-65.degree. C.-65.degree. C.-65.degree.
C.-65.degree. C.-65.degree. C.-65.degree. C.-65.degree.
C.-65.degree. C.-65.degree. C.-65.degree. C.-50.degree. C.,
extruder screws speed of 450 rpm, and a total flow rate of 40 kg/h.
The PCL is introduced in Zone 1 at 32 kg/h and the liquid
composition LC-1 in Zone 5 at 8 kg/h using a volumetric pump. 20%
of the liquid enzymatic composition was introduced to the PCL based
on the total weight of the extruded masterbatch.
[0363] In parallel, a masterbatch MB-SC1 comprising PCL and the
solid composition SC-1 was prepared on a co-rotating twin-screw
extruder (Leistritz ZSE 18MAXX) with the following parameters:
temperature profile of 70.degree. C.-70.degree. C.-70.degree.
C.-70.degree. C.-70.degree. C.-65.degree. C.-65.degree.
C.-65.degree. C.-65.degree. C.-65.degree. C., screws speed of 150
rpm, and a total flow rate of 2 kg/h. 22% of the solid enzymatic
composition was introduced to the PCL based on the total weight of
the masterbatch using a gravimetric feeder in Zone 7. The cooling
and granulation system of both masterbatches were the same as
detailed in Example 1.2.
[0364] Both masterbatches MB-LC1 and MB-SC1 thus comprise the same
biological entities concentration.
3.2--Production of Rigid Plastic by Injection Molding
[0365] Plastic dumbbells having thickness of 4 mm and a total
length of 170 mm were produced using an injection molding machine
(KM 50t/380 CX ClassiX).
[0366] Dumbbells were produced from an injection PLA grade
NatureWorks.RTM. Ingeo.TM. 3251D and the masterbatch MB-LC1
described in 3.1. Control dumbbells were produced from same PLA
grade and masterbatch MB-SC1 described in 3.1. 100% PLA dumbbells
were also produced for standardized mechanical
characterization.
[0367] Before manufacturing the rigid articles, PLA and MB-LC1 were
dried using a desiccator for 40 h at 50.degree. C. and MB-SC1 was
dried in a vacuum oven at 50.degree. C. for 48 h. The rigid plastic
articles were made by use of 95% by weight of the PLA-based matrix
and 5% by weight of a masterbatch.
[0368] Injection molding parameters for each article are detailed
in Table 25:
TABLE-US-00025 TABLE 25 Injection molding parameters for dumbbells
production Set temperatures in barrel Injection Hold Mold zones,
from feed zone to pressure pressure Molding temperature Composition
the front zone (.degree. C.) (bar) (bar) cycle (s) (.degree. C.)
RA- 95% PLA + 40/145/150/150/160/160 1000 850 70 30 LC1 5% MB-LC1
RA- 95% PLA + 40/145/150/150/160/160 1005 900 70 30 SC1 5%
MB-SC1
3.3--Tensile and Impact Characterization of Plastic Articles
[0369] Tensile and impact properties of the rigid plastic article
produced from the liquid composition of the invention and of the
control plastic article made from a solid composition were
characterized.
[0370] Tensile Test
[0371] Tensile tests were carried using a Zwick Roell testing
machine equipped with 20 kN force sensor. The tests were carried
out according to ISO 527-1 standard and the results of the test are
shown in Table 26.
TABLE-US-00026 TABLE 26 Tensile properties of the rigid plastic
article produced from the liquid composition of the invention
(RA-LC1) and control (RA-SC1) Elastic Maximum Strain at Stress
Strain Modulus stress maximum at break at break Sample (GPa)
.sigma.m (MPa) stress .epsilon.m (%) .sigma.b (MPa) .epsilon.b (%)
RA-LC1 2.2 55 3 55 3 RA-SC1 2.2 56 3 57 3
[0372] Rigid article produced from a masterbatch from a liquid
composition does not show significant difference in measured
mechanical characteristics showing that the use of a liquid
composition of the invention has no severe impact on the elastic
Modulus, maximum stress, strain at maximum stress, stress at break
and strain at break of the rigid article produced from such
composition of the invention.
[0373] Charpy Impact Test
[0374] Tests were carried according to the NF EN ISO 179-1 Standard
using a Zwick pendulum impact tester. Test bars were cut from the
injected specimens using a heated cutting plier. Bars dimensions
are 4 mm*10 mm*80 mm. The results of the test are shown in Table
27.
TABLE-US-00027 TABLE 27 Impact properties of the rigid plastic
article produced from the liquid composition of the invention
(RA-LC1) and control (RA-SC1) Sample Impact strength (KJ/m.sup.2)
RA-LC1 21.81 RA-SC1 15.19
[0375] Rigid article of the invention produced from a liquid
composition of the invention shows a better impact resistance than
those produced from a solid biological entities composition. This
is certainly due to the fine distribution of the biological
entities in the plastic article.
3.4--Depolymerization Test:
[0376] Tests of depolymerization have been performed, on injected
rigid article RA-LC1 produced from the liquid composition of the
invention. Firstly, the rigid article was coarsely ground, immersed
in liquid nitrogen and then ground using Ultra-Centrifugal Mill ZM
200 RETSCH equipped with a 500 .mu.m grid. 100 mg of this powder
were weighted, introduced and confined in the dialysis tube. The
tube was placed in 50 mL of 0.1M Tris buffer pH 9.5. The
depolymerization was started by incubating each sample at
45.degree. C., 150 rpm in a Infors HT Multitron Pro incubation
shaker. Aliquots of 1 mL of buffer were sampled regularly and
filtered on 0.22 .mu.m syringe filter, samples were analyzed by
High Performance 15 Liquid Chromatography (HPLC) with an Aminex
HPX-87H column to monitor the liberation of lactic acid (LA) and
lactic acid dimer. Chromatography system used was an Ultimate 3000
UHPLC system (Thermo Fisher Scientific, Inc. Waltham, Mass., USA)
including a pump module, an autosampler, a column oven thermostated
at 50.degree. C., and an UV detector at 220 nm.
[0377] Eluent was 5 mM H2SO4. Injection was 20 .mu.L of sample. LA
was measured according to 20 standard curves prepared from
commercial LA.
[0378] The level of depolymerization of the rigid article reached
about 10% after 48 h showing the biological entities retain a
polyester degrading activity in the final plastic article produced
from the liquid composition of the invention.
Example 4--Preparation of a Masterbatch Using a Liquid Composition
of the Invention, Use of Such Masterbatch for the Production of
Rigid Sheets and Assessment of the Tensile, Impact and Degradation
Properties of Such Sheets
4.1--Preparation of a Masterbatch Using a Liquid Composition
[0379] Masterbatch composition has been prepared from pellets of
polycaprolactone (PCL) polymer (Capa.TM. 6500 from Perstorp) and
the liquid enzymatic composition of the invention LC-1 described in
example 3.1. The masterbatch was manufactured using a co-rotating
twin-screw extruder CLEXTRAL EV25HT comprising twelve zones Z1 to
Z12, wherein the temperature is independently controlled and
regulated.
[0380] The PCL is introduced in zone 1 at 16 kg/h and the liquid
composition in zone 5 at 4 kg/h using a peristaltic pump, wherein
the zones are heated according to Table 27. 20% of the liquid
composition LC was added to the PCL based on the total weight of
the masterbatch. This masterbatch is designated as MB-LC2.
TABLE-US-00028 TABLE 27 Extruder temperature settings for the
production of the masterbatch Zone Z1 Z2 Z3 Z4 Z5 Z6 Z7 Z8 Z9 Z10
Z11 Z12 MB- Temperature 90 65 65 65 65 65 65 65 65 65 65 65 LC2
[0381] The enzyme activity in the masterbatch was determined
according to the protocol described in Example 1.2. Comparing mass
of active enzyme and theoretical enzyme mass in the masterbatch
enabled the percentage of residual activity in the masterbatches to
be determined. The residual activity of the MB-LC2 masterbatch is
60%.
4.2--Manufacture of Biodegradable Plastic Sheets of the
Invention
[0382] A thermoforming PLA grade Total Corbion Luminy.RTM. LX175
was used for manufacturing 450 .mu.m thick plastic sheets to be
submitted to further standardized impact and tensile
characterization and test of biodegradability.
[0383] For plastic sheets manufacturing, an extruder FAIREX
comprising four zones Z1 to Z4, wherein the temperature is
independently controlled and regulated with a diameter of 45, a
flat die of 220 mm equipped with an adjustable lip at 1.5 mm of
nominal opening and a three cylinders calender was used. Before
extrusion and calendaring, the MB-LC2 and the PLA were dried and
mixed together. The MB-LC2 was dried 20 hours at 40.degree. C. in
vacuum oven and the PLA was dried 4 hours at 40.degree. C. in
dryers.
[0384] Sheets obtained from 0% (negative control), 5% or 10% of
MB-LC2 added on PLA were respectively designated S0, S5 and S10.
The extrusion and calendaring parameters are detailed in Table
28.
TABLE-US-00029 TABLE 28 Extruder and calender settings for sheets
production S0 S5 S10 100% 95% PLA + 90% PLA + Composition PLA 5%
MB-LC 10% MB-LC Set temperatures in extruder 165-165- 160-170-
160-165- zones, from Z1 to Z4 (.degree. C.) 180-180 175-175 170-170
Screw speed rate (rpm) 50 50 49 Pressure (bar) 150.5 154 150.5 Die
temperature (.degree. C.) 175 170 165 Lip opening (mm) 0.6 0.6 0.6
Cylinder temperature (.degree. C.) 40 40 40 Flow rate (kg/h) 24.5
23 23
4.3--Evaluation of Depolymerization of the Plastic Sheets
[0385] In order to evaluate the depolymerization rate of the
plastic sheets a depolymerization test was performed following the
protocol already described in Example 3.4.
[0386] After 8 days, the powder of the sheets S0, S5 and S10 show
respectively a depolymerization rate of the PLA of 0.08%, 0.77% and
13.0% showing that the biological entities retain a polyester
degrading activity in the final plastic article produced from the
liquid composition of the invention (S5 and S10).
4.4--Dart-Test Characterization of Plastic Sheets
[0387] Impact tests were carried out according to NF EN ISO 7765-1,
using the steps method. According to this standard, the sample
where cut directly on the plastic sheet. The tests were performed
using a Labthink BMC-B1 Dart-test machine and the results are
presented in Table 29.
TABLE-US-00030 TABLE 29 Impact properties of plastic sheets m50
(kg) E50 (J) S0 0.158 1.0 S5 0.293 1.9 S10 0.353 2.3
[0388] The results of the impact test show that the sheets produced
from liquid composition of the invention (S5 and S10) show an
improvement of impact resistance compared to the control S0 made of
100% PLA.
4.5--Tensile Characterization of Plastic Sheets
[0389] Tensile tests were carried using a Zwick Roell testing
machine equipped with 20 kN force sensor. The tests were carried
out according to NF EN ISO 527-1 standard. The tensile properties
measured are presented in Table 30.
TABLE-US-00031 TABLE 30 Tensile properties of plastic sheets Strain
at Stress at Strain at Test Elastic Maximum maximum break break
direction- modulus stress .sigma.m stress .sigma.b .epsilon.b
thickness (GPa) (MPa) .epsilon.m (%) (MPa) (%) S0 MD-452 .mu.m 1.91
68 4 60 6 TD-452 .mu.m 1.89 66 3.6 66 3.6 S5 MD-462 .mu.m 1.79 61
3.9 56 4.5 TD-464 .mu.m 1.70 58 3.7 56 3.8 S10 MD-484 .mu.m 1.94 63
4 60 4.3 TD-474 .mu.m 1.65 45 3 18.3 17
[0390] Comparing to a pure PLA sheet (S0), sheets produced from a
masterbatch itself produced from a liquid composition of the
invention and PCL, show an improved flexibility with the increase
of incorporation of such masterbatch in PLA based sheets, while
maintaining enough stiffness required for the intended
application.
Example 5--Preparation of Liquid Compositions of the Invention, and
Use of Such Compositions for the Manufacture of Films Comprising
PCL and PLA
5.1--Preparation of Liquid Compositions of the Invention
[0391] Different liquid compositions of the invention have been
prepared using a commercial protease, Savinase.RTM. 16L (Novozymes)
sold under a liquid form.
[0392] Liquid composition D, E, F and G were obtained according to
the method described in Example 1.1: ultrafiltration and
diafiltration of the commercial Savinase.RTM. 16L on 3.5 Kd
membrane and wherein arabic gum is added as carrier.
[0393] The commercial Savinase.RTM. 16L corresponds to the liquid
composition H and is used as a negative control. Such composition
comprises more than 50% by weight of polyols based on the total
weight of the liquid composition and water.
[0394] Description of the different liquid compositions is resumed
in the Table 31.
TABLE-US-00032 TABLE 31 Description of liquid compositions of the
invention (LC-D, LC-E, LC-F and LC-G) and a negative control
(LC-H). LC-H Commercial Savinase 16L (negative LC-D LC-E LC-F LC-G
control) Dry matter 25.4% 46.9% 66.0% 48.7% 75% (%) including
including including including including including Biological 10.9%
21.9% 31.7% 6.9% 4.5% entities having 12.3% 23.1% 31.8% 40.3% 0%
PLA 2.2% 1.9% 2.5% 1.5% 70.5% Depolymerase Activity Carrier Other
components including polyols and salts Aqueous 74.6% 53.1% 34%
51.3% 25% solvent (water) Total 100% 100% 100% 100% 100% % are
given by weight, based on the total weight of the final liquid
composition
5.2--Preparation of a Masterbatch Using the Composition of the
Invention
[0395] Masterbatch compositions have been prepared from pellets of
polycaprolactone (PCL) polymer (Capa.TM. 6500 from Perstorp) and
compositions of the invention described in Example 3.1, using the
same compounding machine as in Example 1.2.
[0396] According to this experiment, 80% by weight of PCL have been
extruded with 20% by weight of the liquid composition. Parameters
used for each extruded masterbatch are summarized in Table 32.
TABLE-US-00033 TABLE 32 Temperature profile and process parameters
of the compounding process Polymer Liquid composition Speed
Temperature Flow Flow screw Masterbatch profile (.degree. C.)
Introduction rate Introduction rate Rate Composition Z1 to Z10 Zone
(kg/h) Zone (kg/h) (rpm) MB4 PCL/LC- 70-70-70-70- Z2 1.99 Z0 0.51
150 D 70-65-65-65- (80/20) 65-65 MB5 PCL/LC- 70-70-70-70- Z2 2.64
Z0 0.66 150 E 70-65-65-65- (80/20) 65-65 MB6 PCL/LC-F 70-70-70-70-
Z2 1.28 Z0 0.32 150 (80/20) 70-65-65-65- 65-65 MB7 PCL/LC-
70-70-70-70- Z2 2.32 Z0 0.58 150 G 70-65-65-65- (80/20) 65-65 MB8
PCL/LC- 70-70-70-70- Z2 2.16 Z0 0.54 150 (negative H 70-65-65-65-
control) (80/20) 65-65
[0397] Enzyme activity of said masterbatch has been further
determined using the protocol described in Example 1.2. Comparing
mass of active enzyme and theoretical enzyme mass in the
masterbatch enabled the percentage of residual activity in the
masterbatches to be determined. Residual activities of the
masterbatches produced are resumed in the Table 33.
TABLE-US-00034 TABLE 33 Residual activities of masterbatches
containing liquid composition of the invention MB8 (negative MB4
MB5 MB6 MB7 control) PCL/LC-D PCL/LC-E PCL/LC-F PCL/LC-G PCL/LC-H
Residual 22.8% 85.1% 67.3% 71.7% 0% Activity (%) +/-0.2% +/-9.5%
+/-6.3% +/-9.0%
[0398] All masterbatches produced with liquid compositions of the
invention (LC-D to LC-G) demonstrate a high residual activity. On
the opposite, MB8 containing Savinase 16L and corresponding to the
negative control, does not show any residual activity. This result
confirms the interest in extrusion process of liquid compositions
of the invention comprising a specific carrier compared to
commercial formulation already described.
[0399] MB5 and MB7, which have similar water content (or similar
dry matter) but different content of biological entities, show
equivalent residual activity. This result tends to indicate that
protection of the biological entities is equivalent, whatever the
percentage of engaged biological entities.
[0400] Additionally, MB4, produced from the composition containing
the highest quantity of water as compared to compositions used to
produce MB5, MB6 or MB7, show the lowest residual activity. This
result tends to indicate that protection of the biological entities
is increased when the quantity of the aqueous solvent is below 70%,
preferably below 60% and/or when the quantity of dry matter is
above 30%, preferably above 40%, independently from the quantity of
biological entities introduced in the liquid composition of the
invention.
5.3--Manufacture of Biodegradable Plastic Films
[0401] The granulated masterbatch compositions MB4, MB5 and MB6 of
Example 5.2 were used to produce biodegradable polylactic
acid-based plastic articles through an extrusion process. The
biodegradability of said plastic articles was further tested.
Preparation of the PLA-Based Matrix
[0402] The PLA-based matrix was extruded using the twin screw
extruder described in Example 1.2. Composition of this matrix is
42.3% by weight of PLA 4043D by NatureWorks, 51.7% by weight of
PBAT PBE006 by NaturePlast and 6% by weight of CaCO.sub.3 by OMYA.
All materials have been dried before extrusion. PLA and PBAT were
dried about 5 hours in a desiccator at 60 and 40.degree. C.
respectively. Vacuum oven at 40.degree. C.-40 mb for 16 h was used
for calcium carbonate.
[0403] Temperature was set at 185.degree. C. in the ten zones of
the extruder. The speed screw rate was 175 rpm, and total input
mass rate was about 5 kg/h. CaCO.sub.3 was introduced in zone 7 to
the melted polymers using a gravimetric feeder to obtain the
PLA-based matrix. The resulting extrudate was cooled in a
cold-water bath before pelletizing.
Masterbatches
[0404] Masterbatches MB4-MB5-MB6 described in Example 5.2 are used
to produce the plastic films.
Film Blowing Step
[0405] Before film blowing extrusion, masterbatches and PLA-based
matrix were dried in vacuum oven at 50.degree. C.-40 mb for 15 h.
Blends were prepared in order to introduce the same quantity of
enzyme in all the films, based on theoretical enzyme mass in the
masterbatch and according to Table 34. For Film E and F, it was
necessary to add PCL 6500 (also dried following the same
conditions) in order to obtain identical composition in all the
films.
TABLE-US-00035 TABLE 34 composition of manufactured films PLA-
based MB4 MB5 MB6 Film reference Matrix PCL/LC-D PCL/LC-E PCL/LC-F
PCL 6500 Film D 90% 10% -- -- -- (P1340/Fi-01) Film E 90% -- 4.2%
-- 5.8% (P1341/Fi-01) Film F 90% -- -- 4.8% 5.2% (P1342/Fi-01)
Blowing was realized using the same machine and parameters
described in example 1.3.
5.4--Tests of Depolymerization
[0406] Tests of depolymerization have been performed on plastic
films produced in Example 5.3, according to the protocol described
in example 1.4.
[0407] Hydrolysis of plastic films was calculated based on LA and
dimer of LA released. Percentage of degradation is calculated
regarding the percentage of PLA in the films.
[0408] Results of the depolymerization of the films, after 4 days,
are shown in Table 35.
TABLE-US-00036 TABLE 35 Comparison of the depolymerization of the
films produced from the compositions of the invention (LC-D, LC-E,
and LC-F) Depolymerization after 4 days Film D-Comprising MB4
(PCL/LC-D) 15.3% Film E-Comprising MB5 (PCL/LC-E) 23.7% Film
F-Comprising MB6 (PCL/LC-F) 44.7%
[0409] All films produced with the compositions of the invention
show a high depolymerization rate, indicating presence of active
enzyme. The more the liquid formulation of the invention contain
dry matter, the more degradation yield reached is high. This result
confirms that a higher dry matter in the composition of the
invention results in a higher protection of the biological entities
during both extrusion processes (masterbatch production and plastic
article production).
Example 6--Use of a Composition of the Invention for the
Manufacture of Films Comprising PLA 6.1--Preparation of
Masterbatches Using the Composition of the Invention and PLA and
Assessment of the Residual Activity of Such Masterbatches
[0410] The liquid composition of the invention LC-1 from example
3.1 and two grades of polylactic acid (PLA) were used for
manufacturing masterbatches: an amorphous grade Luminy LX930U from
Total Corbion (melting temperature below 140.degree. C.) and a
semi-crystalline grade Ingeo.TM. Biopolymer 4043D from NatureWorks
(melting temperature above 140.degree. C.).
[0411] Polylactic acid based masterbatches designated as MB-PLA1,
MB-PLA2 and MB-PLA3 were prepared on a co-rotating twin-screw
extruder (Leistritz ZSE 18MAXX) with screws speed of 150 rpm and a
total flow rate of 2 kg/h. Extrusion temperatures are detailed in
Table 36 below. The PLA was introduced in the non-heated feeding
zone (Z0), and LC-1 was introduced in Z6 using a Brabender pump.
The cooling and granulation system of both masterbatches were the
same as detailed in Example 1.2. Composition of the masterbatches
are also showed in Table 36.
TABLE-US-00037 TABLE 36 Temperature profile and process parameters
of the compounding process Z10 Composition Zone Z1 Z2 Z3 Z4 Z5 Z6
Z7 Z8 Z9 (die) MB 80% PLA T.degree. C. 135 135 135 135 135 120 120
120 120 120 PLA1 LX930U + 20% LC-1 MB- 90% PLA T.degree. C. 135 135
135 135 135 120 120 120 120 120 PLA2 LX930U + 10% LC-1 MB- 90% PLA
T.degree. C. 145 145 145 145 145 130 130 130 130 130 PLA3 4043D +
10% LC-1
[0412] Tests of depolymerization have been performed, using
masterbatches produced above according to the protocol set in
Example 3.4 and level of depolymerization after 24 h are shown in
table 37.
TABLE-US-00038 TABLE 37 Level of depolymerization of masterbatches
Level of depolymerization after 24 h MB-PLA1 92.70% MB-PLA2 84.60%
MB-PLA3 10.50%
[0413] Masterbatches based on PLA LX930U with lower melting point
(MB-PLA1 and MB-PLA2), showed higher depolymerization levels than
that of MB-PLA3 based on PLA4043D for which higher extrusion
temperatures have been used (even at equivalent quantity of
biological entities). The activity of the enzyme in the liquid
composition LC-1 is thus significantly better maintained in a lower
process temperature using a PLA with a melting temperature below
140.degree. C. However, the results show that the liquid
composition of the invention is also suitable to be introduced in a
partially or totally molten polymer having a melting point above
140.degree. C. and that the biological entities still preserve a
polymer degrading activity in the masterbatch.
6.2--Production of the Films and Evaluation of Depolymerization
[0414] MB-PLA1 or MB-PLA2, and PLA based matrix from the Example
1.3 (42.3% by weight of PLA 4043D by NatureWorks, 51.7% by weight
of PBAT PBE006 by NaturePlast and 6% by weight of CaCO.sub.3 by
OMYA) were used for the production of films. Before film blowing
extrusion, masterbatches and PLA-based matrix were dried in vacuum
oven at 60.degree. C. for 5 h. Compositions of blends prepared are
shown in Table 38.
TABLE-US-00039 TABLE 38 Composition of manufactured films PLA based
Films matrix MB-PLA1 MB-PLA2 Film 7 90% 10 -- Film 8 90% -- 10 Film
9 80% -- 20
[0415] The film blowing line used and set temperatures are the same
as the Example 1.3. The screw speed rate set was 60 rpm. Cooling
air amplitude and drawing speed were adjusted to obtain a bubble
width of 200 mm a film thickness between 15 and 20 .mu.m.
[0416] Tests of depolymerization have been performed on the films
produced above according to the protocol set in Example 1.4 and
level of depolymerization after 26 days are shown in table 39.
TABLE-US-00040 TABLE 39 Level of depolymerization of films
Percentage of depolymerization Film after 26 days Film 7 13.4% Film
8 5.5% Film 9 8.6%
[0417] The films produced from a masterbatch comprising PLA with a
melting temperature below 140.degree. C. and the composition of the
invention all showed degradation in aqueous media. Film 7 and Film
9 are supposed to contain the same quantity of biological entities,
but the Film 7 based on the most concentrated masterbatch (MB-PLA1
produced from 20% of LC-1) shows a higher level of degradation than
Film 9 based on MB-PLA2 produced from 10% of LC-1.
Example 7--Use of a Composition of the Invention for the
Manufacture of Rigid Plastic Article Comprising PLA and PCL by 3D
Printing
7.1--Preparation of Masterbatch Using the Composition of the
Invention and Assessment of the Residual Activity of Such
Masterbatch
[0418] A liquid composition of the invention LC-1 from example 3.1
has been used for masterbatch preparation. The same extruder and
the same parameters as Example 1.2 were used to prepare a
masterbatch composed of 90% of PCL (Capa.TM. 6500 from Perstorp)
and 10% of liquid composition LC-1 designated as MB9, a screw speed
of 150 rpm and a total flow rate of 2 kg/h were set.
[0419] The enzyme activity in the masterbatch was determined
according to the protocol described in Example 1.2. The residual
activity of MB9 is 87%.
7.2 Filament Manufacturing and 3D Printing of Rigid Plastic Article
Comprising PLA and PCL
[0420] A PLA based filament was manufactured using Ingeo.TM.
Biopolymer 4043D from NatureWorks. Before filament extrusion,
masterbatch MB9 and PLA were dried for 15 h at 50.degree. C. in a
vacuum oven. Masterbatch was dry-blended with PLA in a ratio
30%/70% in weight and then extruded in a single screw extruder
(Scamex--Rheoscam, O 20-11 L/D) at 100.degree. C.-170.degree.
C.-190.degree. C. set in the three zones of the extruder and
180.degree. C. in the die. A screw speed rate of 47 rpm was used.
The extrudate was cooled with pressurized air, the final diameter
of the filament was about 1.75 mm.
[0421] A cartesian type printer was used. This printer, Neocore
model, has a basalt plateau of 30.times.30 cm that can heat up to
200.degree. C. and a single-nozzle E3D equipped with a system of
BondTech filament that can heat up to 400.degree. C. The 3D
printing tests were conducted using 5A tensile specimen geometry
according to ISO 537-2. 3D printing parameters are detailed in
Table 40.
TABLE-US-00041 TABLE 40 3D printing parameters Nozzle diameter 0.4
mm Layer thickness 0.2 mm Nozzle temperature 170.degree. C. Plateau
temperature 40.degree. C. Printing speed 65 to 70 mm/s Specimen
dimension 75 .times. 12.5 .times. 2 mm (volume = 1.203 cm3)
7.3 Depolymerization Test
[0422] Depolymerization tests were carried on 100 mg of micronized
5A tensile specimen (1 mm grid) using the same protocol as in
Example 3.4. The depolymerization of the specimen reach 11% in
buffer pH 9.5 at 45.degree. C. after 8 days (dialysis system).
[0423] Depolymerization results confirm that biological entities
retain polymer degrading activity in a 3D printed plastic article
produced from the composition of the invention, even after a second
heating at high temperature during the 3D printing.
* * * * *