U.S. patent application number 13/121659 was filed with the patent office on 2011-12-22 for aliphatic polyester.
This patent application is currently assigned to BASF SE. Invention is credited to Andreas Fu l, Kai Oliver Siegenthaler, Gabriel Skupin, Motonori Yamamoto.
Application Number | 20110313075 13/121659 |
Document ID | / |
Family ID | 41203927 |
Filed Date | 2011-12-22 |
United States Patent
Application |
20110313075 |
Kind Code |
A1 |
Siegenthaler; Kai Oliver ;
et al. |
December 22, 2011 |
ALIPHATIC POLYESTER
Abstract
The present invention provides a copolymer obtainable by
condensation of i) 90 to 99.5 mol %, based on components i to ii,
of succinic acid; ii) 0.5 to 10 mol %, based on components i to ii,
of one or more C.sub.2-C.sub.8 dicarboxylic acids; iii) 100 mol %,
based on components i to ii, of 1,3-propanediol or 1,4-butanediol,
and having a DIN 53728 viscosity number in the range from 100 to
450 mL/g. The invention further provides a process for producing
the copolymers, polymer blends comprising these copolymers and also
for the use of these copolymers.
Inventors: |
Siegenthaler; Kai Oliver;
(Mannheim, DE) ; Fu l; Andreas; (Heidelberg,
DE) ; Skupin; Gabriel; (Speyer, DE) ;
Yamamoto; Motonori; (Mannheim, DE) |
Assignee: |
BASF SE
Ludwigshafen
DE
|
Family ID: |
41203927 |
Appl. No.: |
13/121659 |
Filed: |
September 22, 2009 |
PCT Filed: |
September 22, 2009 |
PCT NO: |
PCT/EP2009/062261 |
371 Date: |
September 6, 2011 |
Current U.S.
Class: |
521/183 ;
264/328.1; 264/523; 521/182; 523/400; 524/13; 524/15; 524/16;
524/424; 524/425; 524/431; 524/436; 524/447; 524/449; 524/451;
524/47; 524/513; 524/601; 524/602; 525/165; 525/437;
525/440.16 |
Current CPC
Class: |
C08G 63/20 20130101;
C08L 67/02 20130101; C08L 69/00 20130101; C08K 3/013 20180101; C08L
67/00 20130101; C08L 67/04 20130101; C08K 3/01 20180101; C08L 67/00
20130101; C08G 63/16 20130101; C08L 67/00 20130101; C08K 5/0016
20130101; C08G 63/916 20130101; C08L 67/00 20130101; C08L 2666/02
20130101; C08L 2666/14 20130101; C08K 5/0008 20130101; C08L 2666/18
20130101 |
Class at
Publication: |
521/183 ;
264/328.1; 264/523; 525/440.16; 525/437; 525/165; 524/47; 524/13;
524/16; 524/15; 524/425; 524/424; 524/436; 524/431; 524/447;
524/451; 524/449; 524/602; 524/601; 523/400; 524/513; 521/182 |
International
Class: |
C08L 67/02 20060101
C08L067/02; B29C 49/00 20060101 B29C049/00; C08G 63/16 20060101
C08G063/16; C08G 63/00 20060101 C08G063/00; C08L 3/00 20060101
C08L003/00; C08L 97/02 20060101 C08L097/02; C08K 11/00 20060101
C08K011/00; C08K 3/26 20060101 C08K003/26; C08K 3/00 20060101
C08K003/00; C08K 3/30 20060101 C08K003/30; C08K 3/22 20060101
C08K003/22; C08K 3/16 20060101 C08K003/16; C08K 3/34 20060101
C08K003/34; C08L 63/00 20060101 C08L063/00; B29C 45/00 20060101
B29C045/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 29, 2008 |
EP |
08165370.1 |
Claims
1.-10. (canceled)
11. A copolymer obtained by condensation of: i) 90 to 99.5 mol %,
based on components i to ii, of succinic acid; ii) 0.5 to 10 mol %,
based on components i to ii, of azelaic acid, sebacic acid and/or
brassylic acid; iii) 98 to 102 mol %, based on components i to ii,
of 1,3-propanediol or 1,4-butanediol, and iv) 0.01% to 5% by
weight, based on the total weight of said components i to ii, of a
chain extender and/or crosslinker selected from the group
consisting of a polyfunctional isocyanate, isocyanurate, oxazoline,
carboxylic anhydride, epoxide (in particular an epoxy-containing
poly(meth)acrylate), and/or an at least trihydric alcohol or an at
least tribasic carboxylic acid.
12. The copolymer according to claim 11 further comprising: v) 1%
to 80% by weight, based on the total weight of said components i to
iv, of an organic filler selected from the group consisting of
native or plasticized starch, natural fibers, wood meal, comminuted
cork, ground bark, nut shells, ground presscakes (vegetable oil
refining), dried production residues from the fermentation or
distillation of beverages such as, for example, beer, brewed
lemonades, wine or sake and/or an inorganic filler selected from
the group consisting of chalk, graphite, gypsum, conductivity
carbon black, iron oxide, calcium chloride, dolomite, kaolin,
silicon dioxide (quartz), sodium carbonate, titanium dioxide,
silicate, wollastonite, mica, montmorillonites, talcum, glass
fibers and mineral fibers.
13. The copolymer according to claim 11 further comprising: vi)
0.1% to 2% by weight, based on the total weight of said components
i to iv, of at least one stabilizer, nucleating agent, neutralizing
agent, lubricating and release agent, surfactant, wax, antistat,
antifog agent, dye, UV absorber, UV stabilizer or other plastic
additive.
14. The copolymer according to claim 11 further comprising: (vii)
0.1% to 10% by weight, based on the total weight of said components
i to iv, of at least one plasticizer.
15. A copolymer blend comprising: 5% to 95% by weight of a
copolymer according to claim 11 and 95% to 5% by weight of a
polymer selected from the group consisting of polylactic acid,
polycaprolactone, polyhydroxyalkanoate, aliphatic polycarbonate,
chitosan, gluten and an aliphatic polyester such as polybutylene
succinate or polybutylene succinate adipate, 0% to 2% by weight of
a compatibilizer.
16. The process for producing copolymers according to claim 11 by
condensation of said components i) to iii) to form a prepolyester
having a viscosity number (VN) of 50 to 100 mL/g and subsequent
chain extension with diisocyanates or with epoxy-containing
poly(meth)acrylates to form a polyester having a viscosity number
of 100 to 450 mL/g.
17. A method of producing adhesives, dispersions and moldings,
extruded foams, bead foams, nets and self-supporting film/sheet
comprising utilizing the copolymers according to claim 11.
18. A method of producing injection moldings comprising utilizing
the copolymers according to claim 11.
19. A method of producing extrusion-blown or injection stretch
blown moldings comprising utilizing the copolymers according to
claim 11.
Description
[0001] The present invention provides a copolymer obtainable by
condensation of [0002] i) 90 to 99.5 mol %, based on components i
to ii, of succinic acid; [0003] ii) 0.5 to 10 mol %, based on
components i to ii, of one or more C.sub.8-C.sub.20 dicarboxylic
acids; [0004] iii) 98 to 102 mol %, based on components i to ii, of
1,3-propanediol or 1,4-butanediol, and [0005] having a DIN 53728
viscosity number in the range from 100 to 450 mL/g.
[0006] The present invention relates in particular to a copolymer
obtainable by condensation of [0007] i) 90 to 99.5 mol %, based on
components i to ii, of succinic acid; [0008] ii) 0.5 to 10 mol %,
based on components i to ii, of azelaic acid, sebacic acid and/or
brassylic acid; [0009] iii) 98 to 102 mol %, based on components i
to ii, of 1,3-propanediol or 1,4-butanediol, and [0010] iv) 0.01%
to 5% by weight, based on the total weight of said components i to
iii, of a chain extender and/or crosslinker selected from the group
consisting of a polyfunctional isocyanate, isocyanurate, oxazoline,
epoxide (in particular an epoxy-containing poly(meth)acrylate, an
at least trihydric alcohol or an at least tribasic carboxylic
acid.
[0011] The present invention further provides a process for
producing the copolymers, polymer blends comprising these
copolymers and also for the use of these copolymers.
[0012] Polybutylene succinate (PBS) is not always satisfactory with
regard to biodegradability and hydrolysis resistance in
particular.
[0013] EP-A 565 235 discloses aliphatic copolyesters based on
succinic acid and sebacic acid. However, their sebacic acid content
is distinctly higher than that of the copolyesters of the present
invention. The stiffness of this polymer is much reduced compared
with PBS, its heat resistance is impaired, its crystallization rate
is lower and an associated cycle time is increased and therefore
this polymer is not that useful for injection molding.
[0014] It is an object of the present invention to provide an
aliphatic polyester which has good injection-molding properties.
Furthermore, the injection moldings should possess good mechanical
properties and improved biodegradability compared to PBS.
[0015] We have found that this object is achieved, surprisingly
easily, by the copolymers of the present invention.
[0016] The copolyesters described are synthesized in a direct
polycondensation reaction of the individual components. The
dicarboxylic acid derivatives are reacted in this context together
with the diol in the presence of a transesterification catalyst to
directly form the polycondensate of high molecular weight. Zinc,
aluminum and particularly titanium catalysts are typically used.
Titanium catalysts such as tetraisopropyl orthotitanate and
particularly tetrabutyl orthotitanate (TBOT) are superior to the
tin, antimony, cobalt and lead catalysts frequently used in the
literature, tin dioctanoate being an example, because any residual
quantities of the catalyst or catalyst descendant which remain in
the product are less toxic. This fact is particularly important for
biodegradable polyesters, since they pass directly into the
environment when used as composting bags or mulch sheeting for
example.
[0017] A mixture of the dicarboxylic acids is generally initially
heated in the presence of an excess of diol together with the
catalyst for a period of approximately 60-180 min to an internal
temperature of 170 to 230.degree. C. and the water produced is
distilled off. Subsequently, the melt of the prepolyester thus
obtained is typically condensed at an internal temperature of
200:250.degree. C. during 3 to 6 hours at reduced pressure, with
distillative removal of released diol, to the desired viscosity
with a viscosity number (VN) of 100 to 450 mL/g and preferably 120
to 250 mL/g.
[0018] The copolymers of the present invention can additionally be
produced by following the processes described in WO 96/15173 and
EP-A 488 617. It will be advantageous to initially react components
i) to iii) to form a prepolyester having a VN in the range from 50
to 100 mL/g, preferably in the range from 60 to 90 mL/g and then to
react the latter with chain extenders vib), for example with
diisocyanates or with epoxy-containing polymethacrylates, in a
chain-extending reaction to form a polyester having a viscosity
number of 100 to 450 mL/g, preferably 120 to 250 mL/g.
[0019] Acid component i used is 90 to 99.5 mol %, based on acid
components i and ii, preferably 91 to 99 mol % and more preferably
92 to 98 mol % of succinic acid. Succinic acid is obtainable
petrochemically and preferably also from renewable raw materials as
described, for example, in PCT/EP2008/006714. PCT/EP2008/006714
discloses a biotechnological process for production of succinic
acid and 1,4-butanediol from different carbohydrates using
microorganisms from the class of the Pasteurellaceae.
[0020] Acid component ii relates to one or more C.sub.8-C.sub.20
dicarboxylic acids such as octanedioic acid (suberic acid),
nonanedioic acid (azelaic acid), decanedioic acid (sebacic acid),
undecanedioic acid, dodecanedioic acid, tridecanedioic acid
(brassylic acid), tetradecanedioic acid and hexadecanedioic acid.
Preferred dicarboxylic acids are: azelaic acid, sebacic acid and/or
brassylic acid. Particular preference is given to sebacic acid.
Acid component ii is used in 0.5 to 10 mol %, preferably 1 to 9 mol
% and more preferably 2 to 8 mol %, based on acid components i and
ii. Sebacic acid is obtainable from renewable raw materials, in
particular from castor oil. Azelaic acid and brassylic acid are
obtainable for example by proceeding from plant oils as per WO
2008/138892 A1. Such polyesters are notable for excellent
biodegradability [reference: Polym. Degr. Stab. 2004, 85,
855-863].
[0021] Succinic acid and sebacic acid can be used either as free
acid or in the form of ester-forming derivatives. Useful
ester-forming derivatives include particularly the di-C.sub.1- to
C.sub.6-alkyl esters, such as the dimethyl, diethyl, di-n-propyl,
diisopropyl, di-n-butyl, diisobutyl, di-t-butyl, di-n-pentyl,
diisopentyl or di-n-hexyl esters. Anhydrides of the dicarboxylic
acids can likewise be used.
[0022] The dicarboxylic acids or their ester-forming derivatives
can be used individually or in the form of a mixture.
[0023] The diols 1,3-propanediol and 1,4-butanediol are likewise
obtainable from renewable raw materials. Mixtures of the two diols
can also be used. The preferred diol is 1,4-butanediol because of
the relatively high melt temperatures and the better
crystallization of the copolymer formed.
[0024] In general, at the start of the polymerization, the diol
(component iii) is adjusted relative to the acids (components i and
ii) such that the ratio of diol to diacids be in the range from
1.0:1 to 2.5:1 and preferably in the range from 1.3:1 to 2.2:1.
Excess quantities of diol are withdrawn during the
polycondensation, so that an approximately equimolar ratio becomes
established at the end of the polymerization. By "approximately
equimolar" is meant a diol/diacids ratio in the range from 0.98 to
1.02.
[0025] The copolymers mentioned may have hydroxyl and/or carboxyl
end groups in any desired proportion. The aliphatic polyesters
mentioned can also be subjected to end group modification. For
instance, OH end groups can be acid modified by reaction with
phthalic acid, phthalic anhydride, trimellitic acid, trimellitic
anhydride, pyromellitic acid or pyromellitic anhydride. Preference
is given to copolymers having low acid numbers.
[0026] Generally 0.01% to 5% by weight, preferably 0.02% to 3% by
weight and more preferably 0.055% to 2% by weight based on the
total weight of components i to iii of a crosslinker iva and/or
chain extender ivb selected from the group consisting of a
polyfunctional isocyanate, isocyanurate, oxazoline, carboxylic
anhydride such as maleic anhydride, epoxide (in particular an
epoxy-containing poly(meth)acrylate), an at least trihydric alcohol
or an at least tribasic carboxylic acid is used. Useful chain
extenders ivb include polyfunctional and particularly difunctional
isocyanates, isocyanurates, oxazolines or epoxides. The
crosslinkers iva) are generally used in a concentration of 0.01% to
5% by weight, preferably 0.02% to 1% by weight and more preferably
0.05% to 0.5% by weight based on the total weight of components i
to iii. The chain extenders ivb) are generally used in a
concentration of 0.01% to 5% by weight, preferably 0.2% to 4% by
weight and more preferably 0.35% to 2% by weight based on the total
weight of the components i to iii.
[0027] Chain extenders and also alcohols or carboxylic acid
derivatives having three or more functional groups can also be
considered as crosslinkers. Particularly preferred compounds have
three to six functional groups. Examples are tartaric acid, citric
acid, malic acid; trimethylolpropane, trimethyolethane;
pentaerythritol; polyethertriols and glycerol, trimesic acid,
trimellitic acid, trimellitic anhydride, pyromellitic acid and
pyromellitic anhydride. Preference is given to polyols such as
trimethylolpropane, pentaerythritol and particularly glycerol.
Components iv can be used to construct biodegradable polyesters
which are pseudoplastic. Melt rheology improves; the biodegradable
polyesters are easier to process, for example easier to draw into
self-supporting film/sheet by melt-solidification. Compounds Iv
have a shear-thinning effect, i.e. they enhance the
pseudoplasticity of the polymer. Viscosity decreases under
load.
[0028] The term "epoxides" is to be understood as meaning
particularly epoxy-containing copolymer based on styrene, acrylic
ester and/or methacrylic ester. The units which bear epoxy groups
are preferably glycidyl (meth)acrylates. Copolymers having a
glycidyl methacrylate content of greater than 20%, more preferably
greater than 30% and even more preferably greater than 50% by
weight of the copolymer will be found particularly advantageous.
The epoxy equivalent weight (EEW) in these polymers is preferably
in the range from 150 to 3000 and more preferably in the range from
200 to 500 g/equivalent. The weight average molecular weight
M.sub.W of the polymers is preferably in the range from 2000 to 25
000 and particularly in the range from 3000 to 8000. The number
average molecular weight M.sub.n of the polymers is preferably in
the range from 400 to 6000 and particularly in the range from 1000
to 4000. The polydispersity (Q) is generally between 1.5 and 5.
Epoxy-containing copolymers of the abovementioned type are
commercially available, for example from BASF Resins B.V. under the
Joncryl.RTM. ADR brand. Joncryl.RTM. ADR 4368, for example, is
particularly useful as chain extender.
[0029] It is generally sensible to add the crosslinking (at least
trifunctional) compounds at an early stage of the
polymerization.
[0030] Useful bifunctional chain extenders include the following
compounds:
[0031] An aromatic diisocyanate d1 comprises in particular tolylene
2,4-diisocyanate, tolylene 2,6-diisocyanate, 2,2'-diphenylmethane
diisocyanate, 2,4'-diphenylmethane diisocyanate,
4,4'-diphenylmethane diisocyanate, naphthylene 1,5-diisocyanate or
xylylene diisocyanate. Of these, particular preference is given to
2,2'-, 2,4'- and also 4,4'-diphenylmethane diisocyanates. In
general, the latter diisocyanates are used as a mixture. The
diisocyanates will also comprise minor amounts, for example up to
5% by weight, based on the total weight, of urethione groups, for
example for capping the isocyanate groups.
[0032] The term "aliphatic diisocyanate" herein refers particularly
to linear or branched alkylene diisocyanates or cycloalkylene
diisocyanates having 2 to 20 carbon atoms, preferably 3 to 12
carbon atoms, for example 1,6-hexamethylene diisocyanate,
isophorone diisocyanate or methylenebis(4-isocyanatocyclohexane).
Particularly preferred aliphatic diisocyanates are isophorone
diisocyanate and, in particular, 1,6-hexamethylene
diisocyanate.
[0033] The preferred isocyanurates include the aliphatic
isocyanurates which derive from alkylene diisocyanates or
cycloalkylene diisocyanates having 2 to 20 carbon atoms, preferably
3 to 12 carbon atoms, for example isophorone diisocyanate or
methylenebis(4-isocyanatocyclohexane). The alkylene diisocyanates
here may be either linear or branched. Particular preference is
given to isocyanurates based on n-hexamethylene diisocyanate, for
example cyclic trimers, pentamers or higher oligomers of
1,6-hexamethylene diisocyanate.
[0034] 2,2'-Bisoxazolines are generally obtainable via the process
from Angew. Chem. Int. Ed., Vol. 11 (1972), S. 287-288.
Particularly preferred bisoxazolines are those in which R.sup.1 is
a single bond, a (CH.sub.2).sub.z alkylene group, where z=2, 3 or
4, such as methylene, 1,2-ethanediyl, 1,3-propanediyl,
1,2-propanediyl or a phenylene group. Particularly preferred
bisoxazolines are 2,2'-bis(2-oxazoline), bis(2-oxazolinyl)methane,
1,2-bis(2-oxazolinyl)ethane, 1,3-bis(2-oxazolinyl)propane or
1,4-bis(2-oxazolinyl)butane, in particular
1,4-bis(2-oxazolinyl)benzene, 1,2-bis(2-oxazolinyl)benzene or
1,3-bis(2-oxazolinyl)benzene.
[0035] The amounts of compounds iv used range from 0.01% to 5%,
preferably from 0.05% to 2% and more preferably from 0.08% to 1% by
weight, based on the amount of polymer.
[0036] The number average molecular weight (Mn) of the preferred
copolymers is generally in the range from 5000 to 100,000,
particularly in the range from 10,000 to 75,000 g/mol, preferably
in the range from 15,000 to 50,000 g/mol, their weight average
molecular weight (Mw) is generally in the range from 30,000 to
300,000, preferably 60,000 to 200,000 g/mol, and their Mw/Mn ratio
is generally in the range from 1 to 6, preferably in the range from
2 to 4. The viscosity number is generally between 30 and 450 g/mL
and preferably in the range from 50 to 400 g/mL (measured in 50:50
w/w o-dichloro-benzene/phenol). The melting point is in the range
from 85 to 130.degree. C. and preferably in the range from 95 to
120.degree. C.
[0037] The viscosity number (VN) of the copolymers formed is in the
range from 100 to 450 mL/g, preferably in the range from 110 to 300
mL/g and particularly in the range from 120 to 250 mL/g.
[0038] One preferred embodiment comprises selecting 1% to 80% by
weight, based on the total weight of components i to iv, of an
organic filler selected from the group consisting of native or
plasticized starch, natural fibers, wood meal, comminuted cork,
ground bark, nut shells, ground presscakes (vegetable oil
refining), dried production residues from the fermentation or
distillation of beverages such as, for example, beer, brewed
lemonades, wine or sake and/or an inorganic filler selected from
the group consisting of chalk, graphite, gypsum, conductivity
carbon black, iron oxide, calcium chloride, dolomite, kaolin,
silicon dioxide (quartz), sodium carbonate, titanium dioxide,
silicate, wollastonite, mica, montmorillonites, talcum, glass
fibers and mineral fibers.
[0039] Starch and amylose may be native, i.e.,
non-thermoplasticized, or they may be thermoplasticized with
plasticizers such as glycerol or sorbitol for example (EP-A 539,
541, EP-A 575,349, EP 652,910).
[0040] Natural fibers are cellulose fibers, hemp fibers, sisal,
kenaf, jute, flax, abacca, coir fiber or even wood meal.
[0041] Preferred fibrous fillers are glass fibers, carbon fibers,
aramid fibers, potassium titanate fibers and natural fibers, of
which glass fibers in the form of E-glass are particularly
preferred. These can be used as rovings or particularly as chopped
glass in the commercially available forms. The diameter of these
fibers is generally in the range from 3 to 30 .mu.m, preferably in
the range from 6 to 20 .mu.m and more preferably in the range from
8 to 15 .mu.m. The fiber length in the compound is generally in the
range from 20 .mu.m to 1000 .mu.m, preferably in the range from 180
to 500 .mu.m and more preferably in the range from 200 to 400
.mu.m.
[0042] The fillers may have been surface-pretreated, with a silane
compound for example, for superior compatibility with the
thermoplastic.
[0043] Suitable silane compounds are those of the general
formula
(X--(CH.sub.2).sub.n).sub.k--Si--(O--C.sub.mH.sub.2m+1).sub.4-k
where
X is NH.sub.2--,
##STR00001##
[0044] HO--,
[0045] n is a whole number from 2 to 10, preferably 3 to 4 m is a
whole number from 1 to 5, preferably 1 or 2 k is a whole number
from 1 to 3, preferably 1.
[0046] Preferred silane compounds are aminopropyltrimethoxysilane,
aminobutyltrimethoxy-silane, aminopropyltriethoxysilane,
aminobutyltriethoxysilane and also the corresponding silanes which
comprise a glycidyl group as substituent X, or halosilanes.
[0047] The amount of silane compound used for surface coating is
generally in the range from 0.01% to 2%, preferably 0.025% to 1.0%
and particularly 0.05% to 0.5% by weight (based on C).
[0048] The biodegradable polyester blends of the present invention
may comprise further ingredients which are known to a person
skilled in the art but which are not essential to the present
invention. Examples are the materials customarily added in plastics
technology, such as stabilizers; nucleating agents, neutralizing
agents; lubricating and release agents such as stearates
(particularly calcium stearate); plasticizers such as for example
citric esters (particularly tributyl citrate and tributyl
acetylcitrate), glyceric esters such as triacetylglycerol or
ethylene glycol derivatives, surfactants such as polysorbates,
palmitates or laurates, waxes such as for example beeswax or
beeswax ester; antistat, UV absorber; UV stabilizer; antifog agent
or dyes. The additives are used in concentrations of 0% to 5% by
weight and particularly 0.1% to 2% by weight based on the
copolymers of the present invention. Plasticizers may be present in
the copolymers of the present invention at 0.1% to 10% by
weight.
[0049] The biodegradable copolymer blends of the present invention
are produced from the individual components by following known
processes (EP 792,309 and U.S. Pat. No. 5,883,199). For example,
all the blending partners can be mixed and reacted in one process
step in mixing apparatuses known to one skilled in the art, for
example kneaders or extruders (in particular twin- or multishaft
extruder), at elevated temperatures, for example in the range from
120.degree. C. to 300.degree. C., preferably 150.degree. C. to
250.degree. C.
[0050] Typical copolymer blends comprise:
[0051] 5% to 95% by weight, preferably 20% to 80% by weight and
more preferably 40% to 75% by weight of a copolymer of the present
invention and
[0052] 95% to 5% by weight, preferably 80% to 20% by weight and
more preferably 60% to 40% by weight of a polymer selected from the
group consisting of polylactic acid, polycaprolactone,
polyhydroxyalkanoate, aliphatic polycarbonate, chitosan and gluten
and/or a polyester based on aliphatic diols and aliphatic/aromatic
dicarboxylic acids such as polybutylene succinate (PBS),
polybutylene succinate adipate (PBSA), poly(butylene
adipate-co-terephthalate) (PBAT).
[0053] The copolymer blends preferably comprise in turn 0.05% to 2%
by weight of a compatibilizer. Preferred compatibilizers are
carboxylic anhydrides such as maleic anhydride and particularly the
above-described epoxy-containing copolymers based on styrene,
acrylic ester and/or methacrylic ester. The epoxy-bearing units are
preferably glycidyl (meth)acrylates. Epoxy-containing copolymers of
the abovementioned type are commercially available, for example
from BASF Resins B.V. under the Joncryl.RTM. ADR brand.
Joncryl.RTM. ADR 4368 for example is particularly useful as a
compatibilizer.
[0054] Polylactic acid for example is useful as a biodegradable
polyester. Polylactic acid having the following profile of
properties is preferably used: [0055] an ISO 1133 MVR melt volume
rate at 190.degree. C. and 2.16 kg of 0.5--preferably 2- to 30
ml/10 minutes [0056] a melting point below 175.degree. C.; [0057] a
glass transition point Tg above 55.degree. C. [0058] a water
content of less than 1000 ppm [0059] a residual monomer content
(L-lactide) of less than 0.3% [0060] a molecular weight of greater
than 80 000 daltons.
[0061] Preferred polylactic acids are for example NatureWorks.RTM.
3001, 3051, 3251, 4032 or 4042D (polylactic acids from NatureWorks
or NL-Naarden and USA Blair/Nebraska).
[0062] Polyhydroxyalkanoates are primarily poly-4-hydroxybutyrates
and poly-3-hydroxy-butyrates, but further comprise copolyesters of
the aforementioned hydroxybutyrates with 3-hydroxyvalerates.
Poly-4-hydroxybutyrates are known from Metabolix in particular.
They are marketed under the trade name of Mirel.RTM..
Poly-3-hydroxybutyrates are marketed for example by PHB Industrial
under the trade name of Biocycle.RTM. and by Tianan under the name
of Enmat.RTM..
[0063] The molecular weight Mw of the polyhydroxyalkanoates is
generally in the range from 100,000 to 1,000,000 and preferably in
the range from 300,000 to 600,000.
[0064] Partly aromatic polyesters based on aliphatic diols and
aliphatic/aromatic dicarboxylic acids also comprise polyester
derivatives such as polyether esters, polyester amides or polyether
ester amides. Suitable partly aromatic polyesters include linear
non-chain-extended polyesters (WO 92/09654). Preference is given to
chain-extended and/or branched partly aromatic polyesters. The
latter are known from the above-cited references WO 96/15173 to
15176, 21689 to 21692, 25446, 25448 or WO 98/12242, which are each
expressly incorporated herein by reference. Mixtures of different
partly aromatic polyesters are similarly suitable. Partly aromatic
polyesters are to be understood as meaning in particular products
such as Ecoflex.RTM. (BASF Aktiengesellschaft), Eastar.RTM. Bio and
Origo-Bi.RTM. (Novamont).
[0065] Polycaprolactone is marketed by Daicel under the product
name of Placcel.RTM..
[0066] Aliphatic polycarbonates are in particular polyethylene
carbonate and polypropylene carbonate.
[0067] The copolymers and copolymer blends of the present invention
have superior biodegradability to PBS.
[0068] The "biodegradable" feature shall for the purposes of the
present invention be considered satisfied for any one material or
composition of matter when this material or composition of matter
has a DIN EN 13432 percentage degree of biodegradation equal to at
least 90% after the prescribed periods of time.
[0069] The general effect of biodegradability is that the polyester
(blends) decompose within an appropriate and verifiable interval.
Degradation may be effected enzymatically, hydrolytically,
oxidatively and/or through action of electromagnetic radiation, for
example UV radiation, and may be predominantly due to the action of
microorganisms such as bacteria, yeasts, fungi and algae.
Biodegradability can be quantified, for example, by polyesters
being mixed with compost and stored for a certain time. According
to DIN EN 13432 citing ISO 14855, for example, CO.sub.2-free air is
flowed through ripened compost during composting and the ripened
compost subjected to a defined temperature program.
Biodegradability here is defined via the ratio of the net CO.sub.2
released by the sample (after deduction of the CO.sub.2 released by
the compost without sample) to the maximum amount of CO.sub.2
releasable by the sample (reckoned from the carbon content of the
sample), as a percentage degree of biodegradation. Biodegradable
polyesters/polyester blends typically show clear signs of
degradation, such as fungal growth, cracking and holing, after just
a few days of composting.
[0070] Other methods of determining biodegradability are described
in ASTM D 5338 and ASTM D 6400 for example.
[0071] The copolymers of the present invention are useful for
producing adhesives, dispersions, moldings, extruded foams, bead
foams, self-supporting film/sheet and film ribbons for nets and
fabrics, tubular film, chill roll film with and without orientation
in a further operation, with and without metallization or Siox
coating. Molded articles are particularly molded articles having
wall thicknesses above 200 .mu.m, which are obtainable using
molding processes such as injection molding, injection blow
molding, extrusion/thermoforming, extrusion blow molding and
calendering/thermoforming.
[0072] The components from the present invention copolymers possess
good biodegradability compared with those from PBS. Interesting
fields of application are therefore: catering cutlery, plates,
plant pots, tiles, refillable containers and closures for non-food
applications such as detergents or agricultural products and food
applications, extrusion-blown or injection stretch blown moldings
such as bottles, film applications for inliners, flexible
intermediate bulk containers, carrier bags, freezer bags, beverage
bottles, bottles for other contents, twisted lid containers for
cosmetics, etc.
EXAMPLES
Performance-Related Measurements:
[0073] The molecular weight M.sub.n of partly aromatic polyesters
was determined as follows:
[0074] 15 mg of partly aromatic polyester were dissolved in 10 ml
of hexafluoroisopropanol (HFIP). 125 .mu.l at a time of this
solution were analyzed by means of gel permeation chromatography
(GPC). The measurements were carried out at room temperature.
HFIP+0.05% by weight of potassium trifluoroacetate was used for
elution. The elution rate was 0.5 ml/min. The column combination
used was as follows (all columns from Showa Denko Ltd., Japan):
Shodex.RTM. HFIP-800P (diameter 8 mm, length 5 cm), Shodex.RTM.
HFIP-803 (diameter 8 mm, length 30 cm), Shodex.RTM. HFIP-803
(diameter 8 mm, length 30 cm). The partly aromatic polyesters were
detected by means of an RI detector (differential refractometry).
Narrowly distributed polymethyl methacrylate standard having
molecular weights of M.sub.n=505 to M.sub.n=2,740,000 were used for
calibration. Elution ranges outside this interval were determined
by extrapolation.
[0075] Viscosity numbers were determined in accordance with DIN
53728 Part 3, Jan. 3, 1985. The solvent used was a 50/50 w/w
phenol/o-dichlorobenzene mixture.
[0076] Melting temperatures of partly aromatic polyesters were
determined by DSC measurements using an Exstet DSC 6200R from
Seiko:
[0077] 10 to 15 mg of each sample were heated under nitrogen from
-70.degree. C. to 200.degree. C. at a heating rate of 20.degree.
C./min. Melting temperatures reported for the samples are the peak
temperatures of the melt peaks observed in the course of the
heating. An empty crucible was used as reference in each case.
[0078] The degradation rates of the biodegradable polyester blends
and of the comparative blends were assessed as follows:
[0079] The biodegradable polyester blends and the blends produced
for comparison were each pressed at 190.degree. C. to form films
approximately 30 .mu.m in thickness. These films were each cut into
rectangular pieces having an edge length of 2 cm.times.5 cm. The
weight of these film pieces was determined. The film pieces were
heated for four weeks in a drying cabinet to 58.degree. C. in a
plastics tin filled with moistened composting earth. The remaining
weight of the film pieces was determined at weekly intervals. On
the assumption that biodegradability in these cases can be regarded
as a purely surface process, the slope of the weight decrease
obtained (rate of biodegradation) was determined by computing the
difference from the weight measured after sample taking and the
mass of the film before the start of the test, minus the average
overall weight decrease up to the preceding sample taking. The mass
reduction obtained was also standardized to the surface area (in
cm.sup.2) and also to the time between the current and the
preceding sample taking (in d).
[0080] VICAT softening temperature (Vicat A) was determined in
accordance with ISO 306: 2004 on specimens having a thickness of
0.4 mm.
[0081] Modulus of elasticity, stress at yield and strain at break
were determined by means of a tensile test on pressed sheets about
420 .mu.m in thickness in accordance with ISO 527-3: 2003.
[0082] A puncture resistance test on pressed sheets 420 .mu.m in
thickness was used to measure the ultimate strength and the
fracture energy of the polyesters:
[0083] The testing machinery used was a Zwick 1120 equipped with a
spherical dolly having a diameter of 2.5 mm. The sample, a circular
piece of the sheet to be measured, was clamped perpendicularly
relative to the dolly and this dolly was moved at a constant test
speed of 50 mm/min through the plane of the clamping device. Force
and extension were recorded during the test and used to determine
puncture energy.
EXAMPLES
Example V-1
PBS, Comparative Example
[0084] A mixture of butanediol (93.7 g, 130 mol %), succinic acid
(94.5 g, 100 mol %) and glycerol (0.2 g, 0.1% by weight) was heated
to 200.degree. C. in the presence of TBOT (0.2 g), and the water
formed was distilled off during 30 min. This prepolyester was
subsequently converted at reduced pressure (<5 mbar) to the high
molecular weight polyester. To this end, 1,4-butanediol was
distilled off at a temperature of up to 250.degree. C. The
polyester obtained had a viscosity number of 171 mL/g.
Example 2
PBSSe (S:Se=98:2)
[0085] A mixture of butanediol (70.0 g, 130 mol %), succinic acid
(69.2 g, 98 mol %), sebacic acid (2.4 g, 2 mol %) and glycerol
(0.14 g, 0.1% by weight) was heated to 200.degree. C. in the
presence of TBOT (0.09 mL). The melt was maintained at 200.degree.
C. for 80 min and water was distilled off. Subsequently,
1,4-butanediol was distilled off at reduced pressure (<5 mbar)
and a maximum internal temperature of 250.degree. C. The polyester
was poured out and analyzed after cooling. The polyester obtained
had a viscosity number of 165 mL/g.
Example 3
PBSSe (S:Se=96:4)
[0086] A mixture of butanediol (91.1 g, 130 mol %), succinic acid
(88.2 g, 96 mol %), sebacic acid (6.3 g, 4 mol %) and glycerol
(0.19 g, 0.1% by weight) was heated to 200.degree. C. in the
presence of TBOT (0.2 g). The melt was maintained at 200.degree. C.
for 80 min and water was distilled off. Subsequently,
1,4-butanediol was distilled off at reduced pressure (<5 mbar)
and a maximum internal temperature of 250.degree. C. The polyester
was poured out and analyzed after cooling. The polyester obtained
had a viscosity number of 208 mL/g.
Example 4
PBSSe (S:Se=94:6)
[0087] A mixture of butanediol (90.9 g, 130 mol %), succinic acid
(86.1 g, 94 mol %), sebacic acid (9.4 g, 6 mol %) and glycerol
(0.19 g, 0.1% by weight) was heated to 200.degree. C. in the
presence of TBOT (0.2 g). The melt was maintained at 200.degree. C.
for 80 min and water was distilled off. Subsequently,
1,4-butanediol was distilled off at reduced pressure (<5 mbar)
and a maximum internal temperature of 250.degree. C. The polyester
was poured out and analyzed after cooling. The polyester obtained
had a viscosity number of 220 mL/g.
Example 5
PBSSe (S:Se=92:8)
[0088] A mixture of butanediol (88.7 g, 130 mol %), succinic acid
(82.2 g, 92 mol %), sebacic acid (12.2 g, 8 mol %) and glycerol
(0.19 g, 0.1% by weight) was heated to 200.degree. C. in the
presence of TBOT (0.2 g). The melt was maintained at 200.degree. C.
for 80 min and water was distilled off. Subsequently,
1,4-butanediol was distilled off at reduced pressure (<5 mbar)
and a maximum internal temperature of 250.degree. C. The polyester
was poured out and analyzed after cooling. The polyester obtained
had a viscosity number of 169 mL/g.
Example 6
PBSSe (S:Se=90:10)
[0089] A mixture of butanediol (87.5 g, 130 mol %), succinic acid
(79.4 g, 90 mol %), sebacic acid (15.1 g, 10 mol %) and glycerol
(0.18 g, 0.1% by weight) was heated to 200.degree. C. in the
presence of TBOT (0.2 g). The melt was maintained at 200.degree. C.
for 80 min and water was distilled off. Subsequently,
1,4-butanediol was distilled off at reduced pressure (<5 mbar)
and a maximum internal temperature of 250.degree. C. The polyester
was poured out and analyzed after cooling. The polyester obtained
had a viscosity number of 252 mL/g.
TABLE-US-00001 TABLE 1 Thermal properties (DSC) PBSSe T.sub.g
T.sub.m T.sub.c FWHM Example (S:Se) [.degree. C.] [.degree. C.]
[.degree. C.] [.degree. C.] H.sub.1 [J/g] H.sub.2 [J/g] V-1 100:0
-35 112.5 64.7 10 85 83 2 98:2 -39 111.0 72.5 6 93 82 3 96:4 -39
108.4 61.5 8 85 77 4 94:6 -41 106.6 57.4 8 79 74 5 92:8 -43 103.9
59.8 4 80 72 6 90:10 -45 101.9 57.1 5 77 71
TABLE-US-00002 TABLE 2 Heat resistance (Vicat A) PBSSe Vicat A
Example (S:Se) [.degree. C.] V-1 100:0 105 2 98:2 104 3 96:4 102 4
94:6 102 5 92:8 98 6 90:10 99
TABLE-US-00003 TABLE 3 Mechanical properties E PBSSe modulus Stress
at Strain at Damaging Example (S:Se) [MPa] yield [MPa] break [%]
force [N] V-1 100:0 569 30.6 268 54.7 2 98:2 511 58.6 3 96:4 459
31.2 271 51.7 4 94:6 432 29.1 264 51.2 5 92:8 414 28.9 168 47.9 6
90:10 375 25.6 407 47.0
[0090] The degradation rates were determined as described at the
beginning of the experimental part. Absolute, mutually comparable
rates were obtained. As is apparent from table 4, incorporation of
sebacic acid distinctly enhances the degradation rate.
TABLE-US-00004 TABLE 4 Degradation rates of different PBSSe
copolyesters. Degradation rate PBSSe, absolute Degradation rate
Example mol % Se [(.mu.g/cm.sup.2d] relative V-1 0 31 100% 3 4 81
260% 4 6 110 355% 6 10 166 535%
* * * * *