U.S. patent application number 16/309560 was filed with the patent office on 2019-05-30 for multilayer biodegradable film.
The applicant listed for this patent is NOVAMONT S.P.A.. Invention is credited to Roberto PONTI, Claudio RUSSO.
Application Number | 20190160796 16/309560 |
Document ID | / |
Family ID | 57184650 |
Filed Date | 2019-05-30 |
![](/patent/app/20190160796/US20190160796A1-20190530-M00001.png)
United States Patent
Application |
20190160796 |
Kind Code |
A1 |
PONTI; Roberto ; et
al. |
May 30, 2019 |
MULTILAYER BIODEGRADABLE FILM
Abstract
This invention relates to a multilayer biodegradable film which
is particularly suitable for the manufacture of packaging and is
also characterised by appreciable optical transparency properties
in addition to high level mechanical properties.
Inventors: |
PONTI; Roberto; (Marano
Ticino (NO), IT) ; RUSSO; Claudio; (Novara,
IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NOVAMONT S.P.A. |
Novara |
|
IT |
|
|
Family ID: |
57184650 |
Appl. No.: |
16/309560 |
Filed: |
June 13, 2017 |
PCT Filed: |
June 13, 2017 |
PCT NO: |
PCT/EP2017/064392 |
371 Date: |
December 13, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 27/22 20130101;
B32B 27/285 20130101; C08L 2205/03 20130101; B32B 2307/21 20130101;
B32B 2307/5825 20130101; A01G 13/0275 20130101; B32B 27/40
20130101; B32B 27/42 20130101; B32B 2264/10 20130101; B32B 2264/102
20130101; B32B 2264/104 20130101; B32B 2307/3065 20130101; B32B
27/34 20130101; B32B 2553/00 20130101; B32B 27/36 20130101; C08L
2205/025 20130101; B32B 27/302 20130101; C08J 5/18 20130101; B32B
27/308 20130101; B32B 27/306 20130101; B32B 27/32 20130101; B32B
7/04 20130101; B32B 27/20 20130101; B32B 2307/50 20130101; C08L
67/02 20130101; B32B 27/365 20130101; C08J 2403/02 20130101; C08J
2467/02 20130101; B32B 27/304 20130101; C08L 2310/00 20130101; B32B
27/18 20130101; B32B 2307/7163 20130101; B32B 2307/732 20130101;
B32B 2439/70 20130101; C08L 2203/16 20130101; C08L 2201/06
20130101; B32B 2270/00 20130101; C08J 2367/02 20130101; B32B
2250/24 20130101; C08J 2425/14 20130101; C08L 2205/035 20130101;
C08J 2467/04 20130101; B32B 27/08 20130101; C08L 67/02 20130101;
C08L 3/02 20130101; C08L 67/04 20130101 |
International
Class: |
B32B 27/08 20060101
B32B027/08; B32B 27/22 20060101 B32B027/22; B32B 27/20 20060101
B32B027/20; B32B 27/36 20060101 B32B027/36; B32B 27/30 20060101
B32B027/30; B32B 27/28 20060101 B32B027/28; C08J 5/18 20060101
C08J005/18; C08L 67/02 20060101 C08L067/02; A01G 13/02 20060101
A01G013/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 13, 2016 |
IT |
102016000060486 |
Claims
1. A multilayer film comprising at least one first layer A and at
least one second layer B, in which layers A and B have a mutual
A/B/A arrangement, wherein the layer A and layer B are different
from each other, in which layer A comprises an aliphatic and/or
aliphatic-aromatic biodegradable polyester or a polyvinyl alcohol
or copolymers thereof and in which layer B comprises: i)30-95% by
weight, with respect to the sum of components i-v, of at least one
polyester comprising: a) a dicarboxylic component containing with
respect to the total dicarboxylic component: a1) 35-70% by moles of
units deriving from at least one aromatic dicarboxylic acid, a2)
65-30% by moles of units deriving from at least one saturated
aliphatic dicarboxylic acid, and a3) 0-5% by moles of units
deriving from at least one unsaturated aliphatic dicarboxylic acid;
and b) a diol component comprising with respect to the total diol
component: b1) 95-100% by moles of units deriving from at least one
saturated aliphatic diol, and 2) 0-5% by moles of units deriving
from at least one unsaturated aliphatic diol; ii) 0.1-50% by
weight, with respect to the sum of components i-v, of at least one
polymer of natural origin; iii) 1-40% by weight, with respect to
the sum of components i-v, of at least one polyhydroxy alkanoate;
iv) 0-15% by weight, with respect to the sum of components i-v, of
at least one inorganic filler; and v) 0-5% by weight, with respect
to the sum of components i.-v., of at least one cross-linking agent
and/or chain extender comprising at least one compound having two
and/or multiple functional groups including isocyanate, peroxide,
carbodiimide, isocyanurate, oxazoline, epoxide, anhydride
divinylether groups and mixtures thereof.
2. The multilayer film according to claim 1, in which the said
aliphatic-aromatic polyester in layer A comprises: c) a
dicarboxylic component comprising with respect to the total
dicarboxylic component: c1) 35-70% by moles of units deriving from
at least one aromatic dicarboxylic acid, c2) 65-30% by moles of
units deriving from at least one saturated aliphatic dicarboxylic
acid, and c3) 0-5% by moles of units deriving from at least one
unsaturated aliphatic dicarboxylic acid; and d) a diol component
comprising with respect to the total diol component: d1) 95-100% by
moles of units deriving from at least one saturated aliphatic diol,
and d2) 0-5% by moles of units deriving from at least one
unsaturated aliphatic diol.
3. The multilayer film according to claim 2, in which the saturated
aliphatic dicarboxylic acids in component c2 comprise mixtures
comprising at least 50% by moles of at least one acid selected from
succinic acid, adipic acid, azelaic acid, sebacic acid, brassylic
acid, their C.sub.1-C.sub.24, preferably C.sub.1-C.sub.4, esters
and mixtures thereof.
4. The multilayer film according to claim 3, in which the saturated
aliphatic dicarboxylic acids in component c2 are selected from
adipic acid and azelaic acid or mixtures thereof.
5. The multilayer film according to claim 1, in which in addition
to the said aliphatic and/or aliphatic-aromatic polyester in layer
A the said layer A comprises 1-40% by weight with respect to the
total for layer A of at least one polyhydroxy alkanoate.
6. The multilayer film according to claim 1, in which the saturated
aliphatic dicarboxylic acid of component a2 of the polyester in
layer B comprise mixtures comprising at least 50% by moles of at
least one acid selected from succinic acid, adipic acid, azelaic
acid, sebacic acid, brassylic acid, their C.sub.1-C.sub.24,
preferably C.sub.1-C.sub.4, esters and mixtures thereof.
7. The multilayer film according to claim 6, in which the saturated
aliphatic dicarboxylic acids in said component a2 are selected from
adipic acid and azelaic acid or mixtures thereof.
8. The multilayer film according to claim 1, wherein transmittance
values of more than 90%, Haze values of less than 65%, and clarity
over 20%, measured according to standard ASTM D1003.
9. The multilayer film according to claim 1, said film being
biodegradable under home composting conditions according to UNI
11355.
10. A packaging comprising the multilayer film according to claim
1.
11. The packaging according to claim 10, said packaging being
selected from bags for the carrying of goods and bags for food
packaging.
12. A bag for fruit and vegetables according to claim 11.
13. A mulch film comprising the multilayer film according to claim
1.
14. The multilayer film according to claim 2, in which in addition
to the said aliphatic and/or aliphatic-aromatic polyester in layer
A the said layer A comprises 1-40% by weight with respect to the
total for layer A of at least one polyhydroxy alkanoate.
15. The multilayer film according to claim 3, in which in addition
to the said aliphatic and/or aliphatic-aromatic polyester in layer
A the said layer A comprises 1-40% by weight with respect to the
total for layer A of at least one polyhydroxy alkanoate.
16. The multilayer film according to claim 4, in which in addition
to the said aliphatic and/or aliphatic-aromatic polyester in layer
A the said layer A comprises 1-40% by weight with respect to the
total for layer A of at least one polyhydroxy alkanoate.
17. The multilayer film according to claim 2, in which the
saturated aliphatic dicarboxylic acid of component a2 of the
polyester in layer B comprise mixtures comprising at least 50% by
moles of at least one acid selected from succinic acid, adipic
acid, azelaic acid, sebacic acid, brassylic acid, their
C.sub.1-C.sub.24, preferably C.sub.1-C.sub.4, esters and mixtures
thereof.
18. The multilayer film according to claim 3, in which the
saturated aliphatic dicarboxylic acid of component a2 of the
polyester in layer B comprise mixtures comprising at least 50% by
moles of at least one acid selected from succinic acid, adipic
acid, azelaic acid, sebacic acid, brassylic acid, their
C.sub.1-C.sub.24, preferably C.sub.1-C.sub.4, esters and mixtures
thereof.
19. The multilayer film according to claim 4, in which the
saturated aliphatic dicarboxylic acid of component a2 of the
polyester in layer B comprise mixtures comprising at least 50% by
moles of at least one acid selected from succinic acid, adipic
acid, azelaic acid, sebacic acid, brassylic acid, their
C.sub.1-C.sub.24, preferably C.sub.1-C.sub.4, esters and mixtures
thereof.
20. The multilayer film according to claim 5, in which the
saturated aliphatic dicarboxylic acid of component a2 of the
polyester in layer B comprise mixtures comprising at least 50% by
moles of at least one acid selected from succinic acid, adipic
acid, azelaic acid, sebacic acid, brassylic acid, their
C.sub.1-C.sub.24, preferably C.sub.1-C.sub.4, esters and mixtures
thereof.
Description
DESCRIPTION
[0001] This invention relates to a multilayer biodegradable film
that is particularly suitable for use in the manufacture of
packaging of various kinds, in particular bags for the carrying of
goods and bags for food packaging such as bags for fruit and
vegetables. In addition to having high level mechanical properties,
in particular a high elastic modulus, the said films have
appreciable optical transparency properties.
[0002] The production of packaging, in particular bags for food
packaging such as bags for fruit and vegetables, requires the use
of films which combine good mechanical properties with other
properties that are positive for the consumer, such as in
particular optical transparency properties which enable consumers
to use packaging by identifying an object contained within from the
outside.
[0003] In the biodegradable packaging sector, in addition to
mechanical and optical problems, there is also a need to make use
of materials that are able to degrade once they have reached the
end of their primary use without giving rise to an accumulation of
wastes in the environment. The development of biodegradable films
combining these different properties is in fact a challenge
requiring that different needs, which are often very inconsistent
with each other, be balanced. In fact, although particular
standards for mechanical properties and biodegradability can be
achieved by making use of compositions of materials that share each
of the final properties of the film according to their different
characteristics, achieving high optical transparency properties is
very often impeded specifically by the heterogeneous nature of the
said compositions. For manufacturers of biodegradable packaging
films this means that they must decide whether to use a film having
high level mechanical and biodegradability properties and
non-optimum optical transparency properties or vice versa make use
of aspects associated with the optical properties of the packaging,
thereby accepting lesser performance in terms of mechanical and
biodegradability properties.
[0004] If therefore it were possible to develop a film capable of
balancing these opposite requirements, one therefore characterised
by high level biodegradability and mechanical properties, in
particular a high elastic modulus, and appreciable optical
transparency properties, this would make it possible to overcome
the present problems described above. This invention addresses this
problem and presents a solution to it that is capable of suitably
balancing these different requirements. In particular this
invention relates to a multilayer film comprising at least one
first layer A and at least one second layer B, wherein the layer A
and layer B are different from each other, in which layer A
comprises a biodegradable aliphatic and/or aliphatic-aromatic
polyester or a polyvinyl alcohol or their copolymers, and in which
layer B comprises:
[0005] i) 30-95% by weight, preferably 50-85%, with respect to the
sum of components i.-v., of at least one polyester comprising:
[0006] a) a dicarboxylic component comprising, with respect to the
total dicarboxylic component: [0007] a1) 35-70% by moles,
preferably 40-60% by moles, more preferably 45-60% by moles, of
units deriving from at least one aromatic dicarboxylic acid; [0008]
a2) 65-30% by moles, preferably 60-40% by moles, more preferably
55-40% by moles, of units deriving from at least one saturated
aliphatic dicarboxylic acid; [0009] a3) 0-5% by moles of units
deriving from at least one unsaturated aliphatic dicarboxylic acid;
[0010] b) a diol component comprising, with respect to the total
diol component: [0011] b1) 95-100% by moles of units deriving from
at least one saturated aliphatic diol; [0012] b2) 0-5% by moles of
units deriving from at least one unsaturated aliphatic diol;
[0013] ii) 0.1-50% by weight, preferably 5-40% by weight, with
respect to the sum of components i.-v., of at least one polymer of
natural origin;
[0014] iii) 1-40% by weight, preferably 2-30% by weight, with
respect to the sum of components i.-v., of at least one
polyhydroxyalkanoate;
[0015] iv) 0-15% by weight, with respect to the sum of components
i.-v., of at least one inorganic filler;
[0016] v) 0-5% by weight, preferably 0-0.5% by weight, with respect
to the sum of components i.-v., of at least one cross-linking agent
and/or chain extender comprising at least one compound having two
and/or more functional groups including isocyanate, peroxide,
carbodiimide, isocyanurate, oxazoline, epoxide, anhydride or
divinylether groups and mixtures thereof.
[0017] One particular characteristic of the multilayer film
according to this invention is that its layer structure comprises
at least one layer comprising an aliphatic-aromatic and/or
aliphatic biodegradable polyester or a polyvinyl alcohol or their
copolymers (layer A) and at least one layer comprising a polymer
composition comprising components i.-v. (layer B). Surprisingly it
has been discovered that a multilayer film having this combination
of materials has extraordinarily good mechanical, biodegradability
and optical properties, rendering it suitable for the production of
packaging of various kinds.
[0018] In particular, layer B of the multilayer film according to
this invention structurally comprises a continuous phase and a
dispersed phase capable of rendering the film rapidly biodegradable
under industrial composting conditions and more preferably in home
composting according to standard UNI11355. The said film also has
high level mechanical properties and is extremely thin; if for
example in the form of bags not more than 50 cm tall, not more than
40 cm wide (with or without gussets) and in the case of bags with
handles having handles of width between 5 and 3 cm, and thickness
of less than 15 .mu.m and more preferably less than 12 .mu.m, the
bags are capable of supporting a weight of at least 3 kg, and even
more preferably at least 4 kg under jogging test conditions. By way
of example one type of manual jogging test may be considered to be
lifting the bag 40 cm from the ground 10 consecutive times without
giving rise to any tear. Although the structure of individual layer
B has optical properties that are significantly poorer than those
of the non-biodegradable materials widely used for the production
of packaging, such as for example HDPE, the multilayer film
according to this invention has optical properties similar to those
of HDPE because of its structure, which provides for a combination
of at least one layer A and at least one layer of B, while at the
same time maintaining the biodegradability characteristics of layer
B (industrial composting and more preferably home compostability
and/or dispersability in mechanical mixing processes preceding
treatments involving anaerobiosis). In particular the multilayer
film has optical transmission properties of above 90%, preferably
above 91%, Haze below 65%, preferably below 55%, and clarity of
above 20%, preferably above 40%.
[0019] This invention also relates to packaging of various kinds,
in particular bags for the carrying of goods and bags for food
packaging such as bags for food and vegetables comprising the said
multilayer film.
[0020] The multilayer film according to this invention comprises at
least one layer A and at least one layer of B, preferably
characterised by a mutual arrangement selected from A/B and
A/B/A.
[0021] Layer A
[0022] As far as layer A is concerned, this comprises at least one
aliphatic and/or aliphatic-aromatic polyester or a polyvinyl
alcohol or their copolymers. In the case of an aliphatic-aromatic
polyester, this preferably comprises:
[0023] c) a dicarboxylic component comprising, with respect to the
total dicarboxylic component: [0024] c1) 35-70% by moles,
preferably 40-60% in moles, more preferably 45-60% by moles, of
units deriving from at least one aromatic dicarboxylic acid; [0025]
c2) 65-30% by moles, preferably 60-40% by moles, more preferably
55-40% by moles, of units deriving from at least one saturated
aliphatic dicarboxylic acid; [0026] c3) 0-5% by moles of units
deriving from at least one unsaturated aliphatic dicarboxylic
acid;
[0027] d) a diol component comprising, with respect to the total
diol component: [0028] d1) 95-100% by moles of units deriving from
at least one saturated aliphatic diol; [0029] d2) 0-5% by moles of
units deriving from at least one unsaturated aliphatic diol.
[0030] The aromatic dicarboxylic acids in component c1 are
preferably selected from aromatic dicarboxylic acids of the
phthalic acid type, preferably terephthalic acid or isophthalic
acid, more preferably terephthalic acid, and heterocyclic
dicarboxylic aromatic compounds, preferably 2,5-furandicarboxylic
acid, 2,4-furandicarboxylic acid, 2,3-furandicarboxylic acid,
3,4-furandicarboxylic acid, more preferably 2,5-furandicarboxylic
acid, their esters, salts and mixtures. In a preferred embodiment
the said aromatic dicarboxylic acids comprise: [0031] from 1 to 99%
by moles, preferably from 5 to 95% and more preferably from 10 to
80%, of terephthalic acid, its esters or salts; [0032] from 99 to
1% by moles, preferably from 95 to 5% and more preferably from 90
to 20%, of 2,5-furandicarboxylic acid, its esters or salts.
[0033] The saturated aliphatic dicarboxylic acids in component c2
are preferably selected from saturated C.sub.2-C.sub.24, preferably
C.sub.4-C.sub.13, more preferably C.sub.4-C.sub.11 dicarboxylic
acids, their C.sub.1-C.sub.24, preferably C.sub.1-C.sub.4, alkyl
esters, their salts and mixtures thereof. Preferably the saturated
aliphatic dicarboxylic acids are selected from succinic acid,
2-ethylsuccinic acid, glutaric acid, 2-methylglutaric acid, adipic
acid, pimelic acid, suberic acid, azelaic acid, sebacic acid,
undecanedioic acid, dodecanedioic acid, brassylic acid,
hexadecanedioic acid, octadecanedioic acid and their
C.sub.1-.sub.24 alkyl esters. In a preferred embodiment of this
invention the saturated aliphatic dicarboxylic acid comprise
mixtures comprising at least 50% by moles, preferably more than 60%
by moles, more preferably more than 65% by moles, of succinic acid,
adipic acid, azelaic acid, sebacic acid, brassylic acid, their
C.sub.1-C.sub.24, preferably C.sub.1-C.sub.4, esters, and mixtures
thereof. In a particularly preferred embodiment the said mixtures
comprise or consist of adipic acid and azelaic acid and contain
azelaic acid in a quantity of between 5 and 40% by moles, more
preferably between 10 and 35% by moles of azelaic acid with respect
to the sum of adipic acid and azelaic acid.
[0034] The unsaturated aliphatic dicarboxylic acids in component c3
are preferably selected from itaconic acid, fumaric acid,
4-methylene-pimelic acid, 3,4-bis(methylene)nonandioic acid,
5-methylene-nonandioic acid, their C.sub.1-C.sub.24, preferably
C.sub.1-C.sub.4, alkyl esters, their salts and mixtures thereof. In
a preferred embodiment of this invention the unsaturated aliphatic
dicarboxylic acids comprise mixtures comprising at least 50% by
moles, preferably more than 60% by moles, more preferably more than
65% by moles, of itaconic acid and its C.sub.1-C.sub.24, preferably
C.sub.1-C.sub.4, esters. More preferably the unsaturated aliphatic
dicarboxylic acids consist of itaconic acid.
[0035] As far as the saturated aliphatic diols in component d1 are
concerned, these are preferably selected from 1,2-ethanediol,
1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol,
1,6-hexanediol, 1,7-heptanediol, 1, 8-octanediol, 1,9-nonanediol,
1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol,
1,13-tridecanediol, 1,4-cyclohaxanedimethanol, neopentylglycol,
2-methyl-1,3-propanediol, dianhydrosorbitol, dianhydromannitol,
dianhydroiditol, cyclohexanediol, cyclohexanmethanediol,
dialkyleneglycols and polyalkylene glycols having a molecular
weight of 100-4000, such as for example polyethylene glycol,
polypropylene glycol and mixtures thereof. Preferably the diol
component comprises at least 50% by moles of one or more diols
selected from 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol. More
preferably the diol component comprises or consists of
1,4-butanediol.
[0036] As far as the unsaturated aliphatic diols in component d2
are concerned, these are preferably selected from cis
2-buten-1,4-diol, trans 2-buten-1,4-diol, 2-butyn-1,4-diol, cis
2-penten-1,5-diol, trans 2-penten 1,5 diol, 2-pentyn 1,5 diol, cis
2-hexen-1,6-diol, trans 2-hexen-1,6-diol, 2-hexyn-1,6-diol, cis
3-hexen-1,6-diol, trans 3-hexen-1,6-diol, 3-hexyn-1,6-diol.
[0037] In the case of an aliphatic polyester, this preferably
comprises:
[0038] c) a dicarboxylic component comprising, with respect to the
total dicarboxylic component: [0039] e1) 95-100% by moles of units
deriving from at least one aliphatic dicarboxylic acid; [0040] e2)
0-5% by moles of units deriving from at least one unsaturated
aliphatic dicarboxylic acid;
[0041] f) a diol component comprising, with respect to the total
diol component: [0042] f1) 95-100% by moles of units deriving from
at least one saturated aliphatic diol; [0043] f2) 0-5% by moles of
units deriving from at least one unsaturated aliphatic diol.
[0044] The saturated aliphatic dicarboxylic acids in component e1
are preferably selected from saturated C.sub.2-C.sub.24, preferably
C.sub.4-C.sub.13, more preferably C.sub.4-C.sub.11 dicarboxylic
acids, their C.sub.1-C.sub.24, preferably C.sub.1-C.sub.4, alkyl
esters, their salts and mixtures thereof. Preferably the saturated
aliphatic dicarboxylic acids are selected from succinic acid,
2-ethylsuccinic acid, glutaric acid, 2-methylglutaric acid, adipic
acid, pimelic acid, suberic acid, azelaic acid, sebacic acid,
undecanedioic acid, dodecanedioic acid, brassylic acid,
hexadecanedioic acid, octadecanedioic acid and their
C.sub.1-.sub.24 alkyl esters.
[0045] The unsaturated aliphatic dicarboxylic acids in component e2
are preferably selected from itaconic acid, fumaric acid,
4-methylene-pimelic acid, 3,4-bis(methylene)nonandioic acid,
5-methylene-nonandioic acid, their C.sub.1-C.sub.24, preferably
C.sub.1-C.sub.4, alkyl esters, their salts and mixtures thereof. In
a preferred embodiment of this invention the unsaturated aliphatic
dicarboxylic acids comprise mixtures comprising at least 50% by
moles, preferably more than 60% by moles, more preferably more than
65% by moles, of itaconic acid and its C.sub.1-C.sub.24, preferably
C.sub.1-C.sub.4, esters. More preferably the unsaturated aliphatic
dicarboxylic acids consist of itaconic acid.
[0046] As far as the saturated aliphatic diols in component f1 are
concerned, these are preferably selected from 1,2-ethanediol,
1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol,
1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol,
1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol,
1,13-tridecanediol, 1,4-cyclohaxanedimethanol, neopentylglycol,
2-methyl-1,3-propanediol, dianhydrosorbitol, dianhydromannitol,
dianhydroiditol, cyclohexanediol, cyclohexanmethanediol,
dialkyleneglycols and polyalkylene glycols having a molecular
weight of 100-4000, such as for example polyethylene glycol,
polypropylene glycol and mixtures thereof. Preferably the diol
component comprises at least 50% by moles of one or more diols
selected from 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol. More
preferably the diol component comprises or consists of
1,4-butanediol.
[0047] As far as the unsaturated aliphatic diols in component f2
are concerned, these are preferably selected from cis
2-buten-1,4-diol, trans 2-buten-1,4-diol, 2-butyn-1,4-diol, cis
2-penten-1,5-diol, trans 2-penten 1,5 diol, 2-pentyn 1,5 diol, cis
2-hexen-1,6-diol, trans 2-hexen-1,6-diol, 2-hexyn-1,6-diol, cis
3-hexen-1,6-diol, trans 3-hexen-1,6-diol, 3-hexyn-1,6-diol.
[0048] The Mn molecular weight of the said aliphatic and/or
aliphatic-aromatic polyester in layer A is preferably
.gtoreq.20000, more preferably .gtoreq.40000. As far as the
polydispersity index of the molecular weights, Mw/Mn, is concerned,
this is instead preferably between 1.5 and 10, more preferably
between 1.6 and 5, and even more preferably between 1.8 and
2.7.
[0049] The M.sub.n and M.sub.w molecular weights may be measured
using Gel Permeation Chromatography (GPC). The determination may be
performed with the chromatography system held at 40.degree. C.,
using a set of two columns in series (particle diameters 5 .mu.m
and 3 .mu.m with mixed porosity), a refractive index detector,
chloroform as eluent (flow 0.5 ml/min) and using polystyrene as the
reference standard.
[0050] The terminal acid groups content of the said aliphatic
and/or aliphatic-aromatic polyester in layer A is preferably below
100 meq/kg, preferably below 60 meq/kg and even more preferably
below 40 meq/kg.
[0051] The terminal acid groups content may be measured as follows:
1.5-3 g of polyester are placed in a 100 ml flask together with 60
ml of chloroform. After the polyester has completely dissolved 25
ml of 2-propanol are added, and then 1 ml of deionised water
immediately before analysis. The solution so obtained is titrated
against a previously standardised solution of NaOH in ethanol. An
appropriate indicator is used to determine the end point of the
titration, such as for example a glass electrode for acid-base
titrations in non-aqueous solvents. The terminal acid groups
content is calculated on the basis of the consumption of NaOH
solution in ethanol using the following equation:
Terminal acid groups content ( meq / kg polymer ) = ( V eq - V b )
T 1000 P ##EQU00001##
[0052] in which: V.sub.eq=ml of NaOH in ethanol at the end point of
the titration of the sample; [0053] V.sub.b=ml of solution of NaOH
in ethanol required to reach a pH of 9.5 in the blank titration;
[0054] T=concentration of the NaOH solution in ethanol expressed as
moles/litre; [0055] P=weight of the sample in grams.
[0056] Preferably the said aliphatic and/or aliphatic-aromatic
polyester in layer A has an inherent viscosity of more than 0.3
dl/g (measured using an Ubbelohde viscosity meter for solutions of
concentration 0.2 g/dl in CHCl.sub.3 at 25.degree. C.), preferably
between 0.3 and 2 dl/g, more preferably between 0.4 and 1.1
dl/g.
[0057] The said aliphatic and/or aliphatic-aromatic polyester in
layer A is biodegradable. In the meaning of this invention, by
biodegradable polymer is meant a biodegradable polymer according to
standard EN 13432.
[0058] The said aliphatic and/or aliphatic-aromatic polyester in
layer A can be synthesised according to any of the processes known
in the state of the art. In particular it may advantageously be
obtained using a polycondensation reaction.
[0059] Advantageously the synthesis process may be performed in the
presence of a suitable catalyst. By way of suitable catalysts
mention may for example be made of organometallic compounds of tin,
for example stannoic acid derivatives, titanium compounds, for
example orthobutyl titanate, aluminium compounds, for example
triisopropyl aluminium, compounds of antimony and zinc and
zirconium and mixtures thereof.
[0060] In another embodiment of this invention the said aliphatic
polyester in layer A is the polyester of a hydroxy acid, preferably
a poly-.epsilon.-caprolactone.
[0061] In layer A the said at least one aliphatic and/or
aliphatic-aromatic polyester is advantageously mixed with one or
more other components. In this case layer A comprises a composition
comprising at least one aliphatic and/or aliphatic-aromatic
polyester or a polyvinyl alcohol or their copolymers and preferably
one or more polymers which are not the same as the said aliphatic
and/or aliphatic-aromatic polyester or the said polyvinyl alcohol
or their copolymers, of synthetic or natural origin, which may or
may not be biodegradable, and preferably one or more other
components.
[0062] As far as the polymers which are not the same as the said
aliphatic and/or aliphatic-aromatic polyester or the said polyvinyl
alcohol or their copolymers of synthetic or natural origin, whether
biodegradable or not, are concerned, these are advantageously
selected from the group consisting of polyhydroxyalkanoates, vinyl
polymers, diacid diol polyesters other than polyester i.,
polyamides, polyurethanes, polyethers, polyureas, polycarbonates
and mixtures thereof.
[0063] In the case of non-biodegradable polymers, these are clearly
present in quantities such as not to have a significant effect on
the biodegradability of the final product.
[0064] In a preferred embodiment said composition in layer A
comprises, in addition to the said aliphatic and/or
aliphatic-aromatic polyester or the said polyvinyl alcohol or their
copolymers, between 1 and 40% by weight and more preferably between
5 and 30% by weight with respect to the total of layer A of at
least one polyhydroxyalkanoate more preferably selected from the
group consisting of polyesters of lactic acid,
poly-.epsilon.-caprolactone, polyhydroxybutyrate,
polyhydroxybutyrate-valerate, polyhydroxybutyrate-propanoate,
polyhydroxybutyrate-hexanoate, polyhydroxybutyrate-decanoate,
polyhydroxybutyrate-dodecanoate, polyhydroxybutyrate-hexadecanoate,
polyhydroxybutyrate-octadecanoate,
poly-3-hydroxybutyrate-4-hydroxybutyrate. Preferably the said
polyhydroxyalkanoate comprises at least 80% by weight of one or
more polyesters of lactic acid.
[0065] In a preferred embodiment the lactic acid polyesters are
selected from the group consisting of poly-L-lactic acid,
poly-D-lactic acid, the poly-D-L-lactic acid stereo complex,
copolymers comprising more than 50% by moles of the said lactic
acid polyesters, or mixtures thereof.
[0066] Particularly preferred are lactic acid polyesters containing
at least 95% by weight of repetitive units deriving from L-lactic
or D-lactic acid or combinations thereof, having an Mw molecular
weight of more than 50000 and a shear viscosity of between 50 and
500 Pas, preferably 100-300 Pas (measured according to standard
ASTM D3835 at T=190.degree. C., shear rate=1000.sub.S.sup.-1, D=1
mm, L/D=10).
[0067] In a particularly preferred embodiment of the invention the
lactic acid polyester comprises at least 95% by weight of units
deriving from L-lactic acid, .ltoreq.5% of repetitive units
deriving from D-lactic acid, has a melting point within the range
135-180.degree. C., a glass transition temperature (Tg) in the
range 55-65.degree. C. and an MFR (measured in accordance with
standard ISO 1133-1 at 190.degree. C. and 2.16 kg) within the range
1-50 g/10 min. Commercial examples of lactic acid polyesters having
these properties are for example the products of the Ingeo.TM.
Biopolymer 4043D, 3251D and 6202D make.
[0068] Among the vinyl polymers those preferred are polyethylene,
polypropylene, their copolymers, polyvinyl alcohol, polyvinyl
acetate, polyethylvinyl acetate and polyethylene vinyl alcohol,
polystyrene, chlorinated vinyl polymers and polyacrylates.
[0069] Among the chlorinated vinyl polymers, those which are
intended to be included here, in addition to polyvinyl chloride are
polyvinylidene chloride, polyethylene chloride, poly(vinyl
chloride-vinyl acetate), poly(vinyl chloride-ethylene), poly(vinyl
chloride-propylene), poly(vinyl chloride-styrene), poly(vinyl
chloride-isobutylene) and copolymers in which polyvinyl chloride
represents more than 50% by moles. The said polymers may be random,
block or alternating copolymers.
[0070] As far as the polyamides in the composition according to
this invention are concerned, these are preferably selected from
the group consisting of polyamide 6 and 6,6, polyamide 9 and 9,9,
polyamide 10 and 10,10, polyamide 11 and 11,11, polyamide 12 and
12,12 and their combinations of the 6/9, 6/10, 6/11 and 6/12 type,
their mixtures and both random and block copolymers.
[0071] Preferably the polycarbonates of the composition according
to this invention are selected from the group consisting of
polyalkylene carbonates, more preferably polyethylene carbonates,
polypropylene carbonates, polybutylene carbonates, their mixtures
and random and block copolymers.
[0072] Among the polyethers, those preferred are those selected
from the group consisting of polyethylene glycols, polypropylene
glycols, polybutylene glycols, their copolymers and their mixtures
having molecular weights from 70000 to 500000.
[0073] As far as the diacid diol polyesters which are not the same
as the aliphatic and/or aliphatic-aromatic polyester in layer A are
concerned, these preferably comprise:
[0074] g) a dicarboxylic component comprising, with respect to the
total dicarboxylic component: [0075] g1) 20-100% by moles of units
deriving from at least one aromatic dicarboxylic acid, [0076] g2)
0-80% by moles of units deriving from at least one saturated
aliphatic dicarboxylic acid, [0077] g3) 0-5% by moles of units
deriving from at least one unsaturated aliphatic dicarboxylic
acid;
[0078] h) a diol component comprising, with respect to the total
diol component: [0079] h1) 95-100% by moles of units deriving from
at least one saturated aliphatic diol; [0080] h2) 0-5% by moles of
units deriving from at least one unsaturated aliphatic diol.
[0081] Preferably aromatic dicarboxylic acids g1, saturated
aliphatic dicarboxylic acids g2, unsaturated aliphatic dicarboxylic
acids g3, saturated aliphatic diols h1 and unsaturated aliphatic
diols h2 for the said polyesters are selected from those described
above for the aliphatic-aromatic polyester in layer A according to
this invention.
[0082] At least one cross-linking agent and/or chain extender may
also be present in the composition of layer A in order to improve
stability to hydrolysis. The said cross-linking agent and/or chain
extender is selected from compounds having two and/or multiple
functional groups including isocyanate, peroxide, carbodiimide,
isocyanurate, oxazoline, epoxy, anhydride or divinylether groups or
mixtures thereof. Preferably the cross-linking agent and/or chain
extender comprises at least one compound having two and/or multiple
functional groups including isocyanate groups. More preferably the
cross-linking agent and/or chain extender comprises at least 25% by
weight of one or more compounds having two and/or multiple
functional groups including isocyanate groups. Particularly
preferred are mixtures of compounds having two and/or multiple
functional groups including isocyanate groups with compounds having
two and/or multiple functional groups including epoxy groups, even
more preferably comprising at least 75% by weight of compounds
having two and/or multiple functional groups including isocyanate
groups.
[0083] The compounds having two and multifunctional groups
including isocyanate groups are preferably selected from
p-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene
diisocyanate, 4,4-diphenylmethane-diisocyanate,
1,3-phenylene-4-chloro diisocyanate, 1,5-naphthalene diisocyanate,
4,4-diphenylene diisocyanate, 3,3'-dimethyl-4,4-diphenylmethane
diisocyanate, 3-methyl-4,4'-diphenylmethane diisocyanate,
diphenylester diisocyanate, 2,4-cyclohexane diisocyanate,
2,3-cyclohexane diisocyanate, 1-methyl 2,4-cyclohexyl diisocyanate,
1-methyl 2,6-cyclohexyl diisocyanate, bis-(isocyanate cyclohexyl)
methane, 2,4,6-toluene triisocyanate, 2,4,4-diphenylether
triisocyanate, polymethylene-polyphenyl-polyisocyanates, methylene
diphenyl diisocyanate, triphenylmethane triisocyanate,
3,3'ditolylene-4,4-diisocyanate, 4,4' -methylenebis
(2-methyl-phenyl isocyanate), hexamethylene diisocyanate,
1,3-cyclohexylene diisocyanate, 1,2-cyclohexylene diisocyanate and
their mixtures. In a preferred embodiment the compound containing
isocyanate groups is 4,4-diphenylmethane-diisocyanate.
[0084] As far as the compounds having two and/or multiple
functional groups including peroxide groups are concerned, these
are preferably selected from benzoyl peroxide, lauroyl peroxide,
isononanoyl peroxide, di-(t-butylperoxyisopropyl)benzene, t-butyl
peroxide, dicumyl peroxide,
alpha,alpha-di(t-butylperoxy)diisopropylbenzene,
2,5-dimethyl-2,5-di(-butylperoxy)hexane, t-butyl cumyl peroxide,
di-t-butylperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hex-3-yne,
di(4-t-butylcyclohexyl)peroxy dicarbonate, dicetyl
peroxydicarbonate, dimyristyl peroxydicarbonate,
3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane,
di(2-ethylhexyl) peroxydicarbonate and mixtures thereof.
[0085] The compounds having two and/or multiple functional groups
including carbodiimide groups which are preferably used in the
composition according to this invention are selected from
poly(cyclooctylene carbodiimide), poly(1,4-dimethylencyclohexylene
carbodiimide), poly(cyclohexylene carbodiimide), poly(ethylene
carbodiimide), poly(butylene carbodiimide), poly(isobutylene
carbodiimide), poly(nonylene carbodiimide), poly(dodecylene
carbodiimide), poly(neopentylene carbodiimide),
poly(1,4-dimethylene phenylene carbodiimide),
poly(2,2',6,6'-tetraisopropyldiphenylene carbodiimide)
(Stabaxol.RTM. D), poly(2,4,6-triisopropyl-1,3-phenylene
carbodiimide) (Stabaxol.RTM. P-100), poly(2,6
diisopropyl-1,3-phenylene carbodiimide) (Stabaxol.RTM. P),
poly(tolyl carbodiimide), poly(4,4'-diphenylmethane carbodiimide),
poly(3,3'-dimethyl-4,4'-biphenylene carbodiimide), poly(p-phenylene
carbodiimide), poly(m-phenylene carbodiimide),
poly(3,3'-dimethyl-4,4'-diphenylmethane carbodiimide),
poly(naphthylene carbodiimide), poly(isophorone carbodiimide),
poly(cumene carbodiimide), p-phenylene bis(ethylcarbodiimide),
1,6-hexamethylene bis(ethylcarbodiimide), 1,8-octamethylene
bis(ethylcarbodiimide), 1,10-decamethylene bis(ethylcarbodiimide),
1,12 dodecamethylene bis(ethylcarbodiimide) and mixtures
thereof.
[0086] Examples of compounds having two and multiple functional
groups including epoxy groups which may advantageously be used in
the composition according to this invention are all the
polyepoxides from epoxidated oils and/or from
styrene-glycidylether-methylmethacrylate or
glycidylether-methylmethacrylate, included within a range of
molecular weights between 1000 and 10000 and having an epoxide
number per molecule within the range 1 to 30 and preferably between
5 and 25, the selected epoxides in the group comprising:
diethyleneglycol diglycidylether, polyethyleneglycol diglycidyl
ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether,
1,2-epoxybutane, polyglycerol polyglycidyl ether, isoprene
diepoxide, and cycloaliphatic diepoxides, 1,4-cyclohaxanedimethanol
diglycidyl ether, glycidyl 2-methylphenyl ether, glycerol
propoxylatotriglycidyl ether, 1,4-butanediol diglycidyl ether,
sorbitol polyglycidyl ether, glycerol diglycidyl ether,
tetraglycidyl ethers of meta-xylenediamine and diglycidyl ether or
bisphenol A and mixtures thereof.
[0087] Together with the compounds having two and multiple
functional groups including isocyanate, peroxide, carbodiimide,
isocyanurate, oxazoline, epoxy, anhydride and divinylether groups
such as for example those described above, catalysts may also be
used to raise the reactivity of the reactive groups. In the case of
the polyepoxides, salts of fatty acids, even more preferably
calcium and zinc stearates, may preferably be used.
[0088] In a particularly preferred embodiment of the invention the
cross-linking agent and/or chain extender for the composition in
layer A comprises compounds including isocyanate groups, preferably
4,4-diphenylmethane-diisocyanate, and/or containing carbodiimide
groups, and/or containing epoxy groups, preferably of the
styrene-glycidylether-methylmethacrylate type.
[0089] A filler may also be present in the composition of layer A,
up to 10% by weight with respect to the total of layer A.
[0090] The composition of layer A of the multilayer film according
to the present invention does not contain starch.
[0091] In addition to the abovementioned components the composition
in layer A preferably also comprises at least one other component
selected from the group consisting of plasticisers, UV stabilisers,
lubricants, nucleating agents, surfactants, antistatic agents,
pigments, flame-retardant agents, compatibilising agents, lignin,
organic acids, antioxidants, anti-mould agents, waxes, process
coadjuvants and polymer components preferably selected from the
group consisting of vinyl polymers, diacid diol polyesters which
are not the aliphatic-aromatic polyesters described above,
polyamides, polyurethanes, polyethers, polyureas or
polycarbonates.
[0092] As far as the plasticisers are concerned, there are
preferably present in the composition of layer A according to this
invention, one or more plasticisers selected from the group
comprising water, polyols having from 2 to 22 carbon atoms,
phthalates, such as for example diisononyl phthalate,
trimellitates, such as for example esters of trimellitic acid with
C.sub.4-C.sub.20 monoalcohols preferably selected from the group
comprising n-octanol and n-decanol, and aliphatic esters having the
following structure:
R.sub.1--O--C(O)--R.sub.4--C(O)--[--O--R.sub.2--O--C(O)--R.sub.5--C(O)---
].sub.m--O--R.sub.3
[0093] in which: [0094] R.sub.1 is selected from one or more groups
comprising H, linear and branched saturated and unsaturated alkyl
residues of the C.sub.1-C.sub.24 type, polyol residues esterified
with C.sub.1-C.sub.24 monocarboxylic acids; [0095] R.sub.2
comprises --CH.sub.2--C(CH.sub.3).sub.2--CH.sub.2-- and
C.sub.2-C.sub.8 alkylene groups, and comprises at least 50% by
moles of the said --CH.sub.2--C(CH.sub.3).sub.2--CH.sub.2-- groups;
[0096] R.sub.3 is selected from one or more groups comprising H,
linear and branched saturated and unsaturated alkyl residues of the
C.sub.1-C.sub.24 type, polyol residues esterified with
C.sub.1-C.sub.24 monocarboxylic acids; [0097] R.sub.4 and R.sub.5
are the same or different, comprise one or more C.sub.2-C.sub.22,
preferably C.sub.2-C.sub.11, more preferably C.sub.4-C.sub.9
alkylenes, and comprise at least 50% by moles of C.sub.7
alkylenes.
[0098] m is a number of between 1 and 20, preferably 2-10, more
preferably 3-7. Preferably, in the said esters at least one of the
groups R.sub.1 and/or R.sub.3 comprises, preferably in quantities
.gtoreq.10% by moles, more preferably .gtoreq.20%, even more
preferably .gtoreq.25% by moles with respect to the total quantity
of R.sub.1 and/or R.sub.3 groups, polyol residues esterified with
at least one C.sub.1-C.sub.24 monocarboxylic acid selected from the
group consisting of stearic acid, palmitic acid, 9-ketostearic
acid, 10-ketostearic acid and mixtures thereof. Examples of
aliphatic esters of this type are described in Italian Patent
Application MI2014A000030 and in PCT Applications
PCT/EP2015/050336, PCT/EP2015/050338.
[0099] When present in layer A the selected plasticisers are
preferably present up to 10% by weight with respect to the total
weight of the composition of layer A itself.
[0100] The lubricants are preferably selected from esters and metal
salts of fatty acids such as for example zinc stearate, calcium
stearate, aluminium stearate and acetyl stearate. Preferably the
composition of layer A according to this invention comprises up to
1% by weight of lubricants, more preferably up to 0.5% by weight
with respect to the total weight of the composition of layer A.
[0101] Examples of nucleating agents include the sodium salt of
saccharine, calcium silicate, sodium benzoate, calcium titanate,
boron nitride, isotactic polypropylene, or low molecular weight
PLA. These additives are preferably added in quantities up to 10%
by weight and more preferably between 2 and 6% by weight with
respect to the total weight of the composition.
[0102] Pigments may also be added if necessary, for example
titanium dioxide, clays, copper phthalocyanine, titanium dioxide,
silicates, iron oxide and hydroxides, carbon black and magnesium
oxide. These additives are preferably added up to 10% by
weight.
[0103] In a preferred embodiment layer A of a multilayer film
according to this invention comprises, with respect to the sum of
components i.-v.: [0104] i) 30-70% by weight of at least one
aliphatic-aromatic polyester; [0105] ii) 20-60% by weight of at
least one aliphatic polyester; [0106] iii) 1-20% by weight of at
least one polyhydroxyalkanoate; [0107] iv) 0-5% by weight,
preferably 0-0.5%, of at least one cross-linking agent and/or a
chain extender comprising at least one compound having two and/or
multiple functional groups including isocyanate, peroxide,
carbodiimide, isocyanurate, oxazoline, epoxy, anhydride or divinyl
ether groups and mixtures thereof; [0108] v) 0-10% by weight,
preferably 0-5%, of at least one filler.
[0109] In a preferred embodiment layer A of a multilayer film
according to this invention comprises, with respect to the sum of
components i.-v.: [0110] i) 60-100% by weight of at least one
aliphatic-aromatic polyester; [0111] ii) 0-20% by weight of at
least one aliphatic polyester; [0112] iii) 0-40% by weight of at
least one polyhydroxyalkanoate; [0113] iv) 0-5% by weight,
preferably 0-0.5%, of at least one cross-linking agent and/or a
chain extender comprising at least one compound having two and/or
multiple functional groups including isocyanate, peroxide,
carbodiimide, isocyanurate, oxazoline, epoxy, anhydride or divinyl
ether groups and mixtures thereof; [0114] v) 0-10% by weight,
preferably 0-5%, of at least one filler.
[0115] In a preferred embodiment layer A of a multilayer film
according to this invention comprises, with respect to the sum of
components i.-v.: [0116] i) 0-20% by weight of at least one
aliphatic-aromatic polyester; [0117] ii) 60-100% by weight of at
least one aliphatic polyester; [0118] iii) 0-40% by weight of at
least one polyhydroxyalkanoate; [0119] iv) 0-5% by weight,
preferably 0-0.5%, of at least one cross-linking agent and/or a
chain extender comprising at least one compound having two and/or
multiple functional groups including isocyanate, peroxide,
carbodiimide, isocyanurate, oxazoline, epoxy, anhydride or divinyl
ether groups and mixtures thereof; [0120] v) 0-10% by weight,
preferably 0-5%, of at least one filler.
[0121] Layer B
[0122] As far as layer B is concerned, this comprises: [0123] i)
30-95% by weight, preferably 50-85% by weight, with respect to the
sum of components i.-v., of at least one polyester comprising:
[0124] a) a dicarboxylic component comprising, with respect to the
total for the dicarboxylic component: [0125] a1) 35-70% by moles,
preferably 40-60% by moles, more preferably 45-60% by moles, of
units deriving from at least one aromatic dicarboxylic acid; [0126]
a2) 70-35% by moles, preferably 60-40% by moles, more preferably
55-40% by moles, of units deriving from at least one saturated
aliphatic dicarboxylic acid; [0127] a3) 0-5% by moles of units
deriving from at least one unsaturated aliphatic dicarboxylic acid;
[0128] b) a diol component comprising, with respect to the total
for the diol component: [0129] b1) 95-100% by moles of units
deriving from at least one saturated aliphatic diol; [0130] b2)
0-5% by moles of units deriving from at least one unsaturated
aliphatic diol; [0131] ii) 0.1-50% by weight, preferably 5-40% by
weight, with respect to the sum of components i.-v., of at least
one polymer of natural origin, [0132] iii) 1-40% by weight,
preferably 2-30% by weight, with respect to the sum of components
i.-v., of at least one polyhydroxyalkanoate; [0133] iv) 0-15% by
weight, with respect to the sum of components i.-v., of at least
one inorganic filler; [0134] v) 0-5% by weight, preferably 0-0.5%
by weight, with respect to the sum of components i.-v., of at least
one cross-linking agent and/or chain extender comprising at least
one compound having two and/or multiple functional groups including
isocyanate, peroxide, carbodiimide, isocyanurate, oxazoline,
epoxide, anhydride or divinyl ether groups and mixtures
thereof.
[0135] The aromatic dicarboxylic acids in component a1 of polyester
i. are preferably selected from aromatic dicarboxylic acids of the
phthalic acid type, preferably terephthalic acid or isophthalic
acid, more preferably terephthalic acid, and heterocyclic
dicarboxylic aromatic compounds, preferably 2,5-furandicarboxylic
acid, 2,4-furandicarboxylic acid, 2,3-furandicarboxylic acid,
3,4-furandicarboxylic acid, more preferably 2,5-furandicarboxylic
acid, their esters, salts and mixtures. In a preferred embodiment
the said aromatic dicarboxylic acids comprise: [0136] from 1 to 99%
by moles, preferably from 5 to 95% and more preferably from 10 to
80%, of terephthalic acid, its esters or salts; [0137] from 99 to
1% by moles, preferably from 95 to 5% and more preferably from 90
to 20%, of 2,5-furandicarboxylic acid, its esters or salts.
[0138] The saturated aliphatic dicarboxylic acids in component a2
of polyester i. are preferably selected from saturated
C.sub.2-C.sub.24, preferably C.sub.4-C.sub.13, more preferably
C.sub.4-C.sub.11 dicarboxylic acids, their C.sub.1-C.sub.24,
preferably C.sub.1-C.sub.4, alkyl esters, their salts and mixtures
thereof. Preferably the saturated aliphatic dicarboxylic acids are
selected from succinic acid, 2-ethylsuccinic acid, glutaric acid,
2-methylglutaric acid, adipic acid, pimelic acid, suberic acid,
azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid,
brassylic acid, hexadecanedioic acid, octadecanedioic acid and
their C.sub.1-.sub.24 alkyl esters. In a preferred embodiment of
this invention the saturated aliphatic dicarboxylic acid comprise
mixtures comprising at least 50% by moles, preferably more than 60%
by moles, more preferably more than 65% by moles, of succinic acid,
adipic acid, azelaic acid, sebacic acid, brassylic acid, their
C.sub.1-C.sub.24, preferably C.sub.1-C.sub.4, esters, and mixtures
thereof. In a particularly preferred embodiment the said mixtures
comprise or consist of adipic acid and azelaic acid and contain
azelaic acid in a quantity of between 5 and 40% by moles, more
preferably between 10 and 35% by moles of azelaic acid with respect
to the sum of adipic acid and azelaic acid.
[0139] The unsaturated aliphatic dicarboxylic acids in component a3
of polyester i. are preferably selected from itaconic acid, fumaric
acid, 4-methylene-pimelic acid, 3,4-bis(methylene)nonandioic acid,
5-methylene-nonandioic acid, their C.sub.1-C.sub.24, preferably
C.sub.1-C.sub.4, alkyl esters, their salts and mixtures thereof. In
a preferred embodiment of this invention the unsaturated aliphatic
dicarboxylic acids comprise mixtures comprising at least 50% by
moles, preferably more than 60% by moles, more preferably more than
65% by moles, of itaconic acid and its C.sub.1-C.sub.24, preferably
C.sub.1-C.sub.4, esters. More preferably the unsaturated aliphatic
dicarboxylic acid comprise itaconic acid.
[0140] As far as the saturated aliphatic diols in component b1 of
polyester i. are concerned, these are preferably selected from
1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol,
1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol,
1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol,
1,12-dodecanediol, 1,13-tridecanediol, 1,4-cyclohaxanedimethanol,
neopentylglycol, 2-methyl-1,3-propanediol, dianhydrosorbitol,
dianhydromannitol, dianhydroiditol, cyclohexanediol,
cyclohexanmethanediol, dialkyleneglycols and polyalkylene glycols
having a molecular weight of 100-4000, such as for example
polyethylene glycol, polypropylene glycol and mixtures thereof.
Preferably the diol component comprises at least 50% by moles of
one or more diols selected from 1,2-ethanediol, 1,3-propanediol,
1,4-butanediol. More preferably the diol component comprises or
consists of 1,4-butanediol.
[0141] As far as the unsaturated aliphatic diols in component b2 of
polyester i. are concerned, these are preferably selected from cis
2-buten-1,4-diol, trans 2-buten-1,4-diol, 2-butyn-1,4-diol, cis
2-penten 1,5 diol, trans 2-penten 1,5 diol, 2-pentyn 1,5 diol, cis
2-hexen-1,6-diol, trans 2-hexen-1,6-diol, 2-hexyn-1,6-diol, cis
3-hexen-1,6-diol, trans 3-hexen-1,6-diol, 3-hexyn-1,6-diol.
[0142] The Mn molecular weight of the polyester i. in layer B is
preferably .gtoreq.20000, more preferably .gtoreq.40000. As far as
the polydispersity index of the molecular weights, Mw/Mn, is
concerned, this is instead preferably between 1.5 and 10, more
preferably between 1.6 and 5, and even more preferably between 1.8
and 2.7.
[0143] The M.sub.n and M.sub.w molecular weights may be measured
using Gel Permeation Chromatography (GPC). The determination may be
performed with the chromatography system held at 40.degree. C.,
using a set of two columns in series (particle diameters 5 .mu.m
and 3 .mu.m with mixed porosity), a refractive index detector,
chloroform as eluent (flow 0.5 ml/min) and using polystyrene as the
reference standard.
[0144] The terminal acid groups content of the polyester i. in
layer B is preferably below 100 meq/kg, preferably below 60 meq/kg,
and even more preferably below 40 meq/kg.
[0145] The terminal acid groups content may be measured using the
method described for the aliphatic-aromatic polyester layer A.
[0146] Preferably the polyester i. in layer B has an inherent
viscosity (measured using an Ubbelohde viscosimeter for solutions
of concentration 0.2 g/dl in CHCl.sub.3 at 25.degree. C.) of over
0.3 dl/g, preferably between 0.3 and 2 dl/g, more preferably
between 0.4 and 1.1 dl/g.
[0147] Preferably polyester i. in layer B is biodegradable. For the
meaning of this invention by biodegradable polymer is meant a
polymer which is biodegradable in accordance with standard EN
13432.
[0148] The said polyester i. in layer B can be synthesised
according to any of the processes known in the state of the art. In
particular it may advantageously be obtained through a
polycondensation reaction.
[0149] Advantageously the synthesis process may be performed in the
presence of a suitable catalyst. By way of suitable catalysts
mention may for example be made of organometallic compounds of tin,
for example stannoic acid derivatives, titanium compounds, for
example orthobutyl titanate, aluminium compounds, for example
triisopropyl aluminium, compounds of antimony and zinc and
zirconium and mixtures thereof.
[0150] The composition of layer B comprises 0.1-50% by weight,
preferably 5-40% by weight, with respect to the sum of components
i.-v., of at least one polymer of natural origin. In the
composition of layer B the polymer of natural origin (component
ii.) is advantageously selected from starch, chitin, chitosan,
alginates, proteins such as gluten, zein, casein, collagen,
gelatin, natural rubbers, rosinic acid and their derivatives.
Preferably, in the composition of layer B the polymer of natural
origin is starch.
[0151] By the term starch is meant all types of starch, that is
flour, native starch, hydrolysed starch, destructured starch,
gelatinised starch, plasticised starch, thermoplastic starch,
biofiller comprising complexed starch or mixtures thereof.
Particularly suitable according to the invention are starches such
as those from potato, maize, tapioca and peas.
[0152] Starches which are capable of easily being destructured or
which have high initial molecular weights, such as for example
potato or maize starch, have proved to be particularly
advantageous.
[0153] The starch may be present as such or in a chemically
modified form, such as for example in the form of starch esters
having a degree of substitution of between 0.2 and 2.5, starch
hydroxypropylate or starch modified with fatty chains.
[0154] In the case of destructured starch reference is made here to
the teaching included in patents EP-0 118 240 and EP-0 327 505,
meaning as such starch processed in such a way as to be
substantially free from the so-called "Maltese crosses" under an
optical microscope in polarised light and the so-called "ghosts"
under an optical microscope with phase contrast.
[0155] Advantageously the starch is destructured by means of an
extrusion process at temperatures of between 110 and 250.degree.
C., preferably 130-180.degree. C., preferably at pressures between
0.1 and 7 MPa, preferably 0.3-6 MPa, preferably providing a
specific energy of more than 0.1 kWh/kg during the said
extrusion.
[0156] Destructuring of the starch preferably takes place in the
presence of 1-40% by weight with respect to the weight of the
starch of one or more plasticisers selected from water and polyols
having from 2 to 22 carbon atoms. As far as the water is concerned,
this may also be that which is naturally present in the starch.
Among the polyols, those preferred are polyols having from 1 to 20
hydroxyl groups containing 2 to 6 carbon atoms, their ethers,
thioethers and organic and inorganic esters. Examples of polyols
are glycerine, diglycerol, polyglycerol, pentaerythritol,
polyglycerol ethoxylate, ethylene glycol, polyethylene glycol,
1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentylglycol,
sorbitol monoacetate, sorbitol diacetate, sorbitol monoethoxylate,
sorbitol diethoxylate, and mixtures thereof. In a preferred
embodiment the starch is destructured in the presence of glycerol
or a mixture of plasticisers comprising glycerol, more preferably
containing between 2 and 90% by weight of glycerol. Preferably the
destructured and cross-linked starch according to this invention
comprises between 1 and 40% by weight of plasticisers with respect
to the weight of the starch.
[0157] When present the starch in the composition of layer B is
preferably in the form of particles having a circular or elliptical
cross section or in any event a cross-section similar to an ellipse
having a mean arithmetic diameter less than 1 micron, and more
preferably of less than 0.5 .mu.m mean diameter, measured using the
major axis of the particle.
[0158] The composition of layer B comprises 1-40% by weight,
preferably 2-30% by weight, with respect to the sum of components
i.-v., of at least one polyhydroxyalkanoate (component iii.),
preferably selected from the group consisting of polyesters of
lactic acid, poly-.epsilon.-caprolactone, polyhydroxybutyrate,
polyhydroxybutyrate-valerate, polyhydroxybutyrate propanoate,
polyhydroxybutyrate-hexanoate, polyhydroxybutyrate-decanoate,
polyhydroxybutyrate-dodecanoate, polyhydroxybutyrate-hexadecanoate,
polyhydroxybutyrate-octadecanoate,
poly-3-hydroxybutyrate-4-hydroxybutyrate. Preferably the said
polyhydroxyalkanoate comprises at least 80% by weight of one or
more polyesters of lactic acid.
[0159] In a preferred embodiment the lactic acid polyesters are
selected from the group comprising poly-L-lactic acid,
poly-D-lactic acid, the poly-D-L-lactic acid stereo complex,
copolymers comprising more than 50% by moles of the said lactic
acid polyesters, or mixtures thereof.
[0160] Particularly preferred are lactic acid polyesters containing
at least 95% by weight of repetitive units deriving from L-lactic
or D-lactic acid or combinations thereof, having an Mw molecular
weight of more than 50000 and a shear viscosity of between 50 and
500 Pas, preferably 100-300 Pas (measured according to standard
ASTM D3835 at T=190.degree. C., shear rate=1000.sub.S.sup.-1, D=1
mm, L/D=10).
[0161] In a particularly preferred embodiment of the invention the
lactic acid polyester comprises at least 95% by weight of units
deriving from L-lactic acid, .ltoreq.5% of repetitive units
deriving from D-lactic acid, has a melting point within the range
135-180.degree. C., a glass transition temperature (Tg) in the
range 55-65.degree. C. and an MFR (measured in accordance with
standard ISO 1133-1 at 190.degree. C. and 2.16 kg) within the range
1-50 g/10 min. Commercial examples of lactic acid polyesters having
these properties are for example the products of the Ingeo.TM.
Biopolymer 4043D, 3251D and 6202D make.
[0162] In the composition of layer B there is present 0-15% by
weight, with respect to the sum of components i.-v., of at least
one inorganic filler (component iv.), which is preferably selected
from kaolin, barytes, clay, talc, calcium and magnesium, iron and
lead carbonates, aluminium hydroxide, diatomaceous earth, aluminium
sulfate, barium sulfate, silica, mica, titanium dioxide,
wollastonite.
[0163] In a preferred embodiment of this invention the inorganic
filler in the composition of layer B comprises talc, calcium
carbonate or their mixtures, present in the form of particles
having a mean arithmetic diameter of less than 10 microns measured
in relation to the major axis of the particles. It has in fact been
discovered that fillers of the abovementioned type which are not
characterised by the said mean arithmetic diameter prove the
disintegratability characteristics significantly less during the
industrial composting of objects containing them.
[0164] In the composition of layer B there is also present from 0
to 5% by weight, preferably 0-0.5% by weight, with respect to the
sum of components i.-v., of at least one cross-linking agent and/or
chain extender (component v.) in order to improve stability to
hydrolysis.
[0165] The said cross-linking agent and/or chain extender is
selected from compounds having two and/or multiple functional
groups including isocyanate, peroxide, carbodiimide, isocyanurate,
oxazoline, epoxy, anhydride or divinylether groups or mixtures
thereof. Preferably the cross-linking agent and/or chain extender
comprises at least one compound having two and/or multiple
functional groups including isocyanate groups. More preferably the
cross-linking agent and/or chain extender comprises at least 25% by
weight of one or more compounds having two and/or multiple
functional groups including isocyanate groups. Particularly
preferred are mixtures of compounds having two and/or multiple
functional groups including isocyanate groups with compounds having
two and/or multiple functional groups including epoxy groups, even
more preferably comprising at least 75% by weight of compounds
having two and/or multiple functional groups including isocyanate
groups.
[0166] The compounds having two and multifunctional groups
including isocyanate groups are preferably selected from
p-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene
diisocyanate, 4,4-diphenylmethane-diisocyanate,
1,3-phenylene-4-chloro diisocyanate, 1,5-naphthalene diisocyanate,
4,4-diphenylene diisocyanate, 3,3'-dimethyl-4,4-diphenylmethane
diisocyanate, 3-methyl-4,4'-diphenylmethane diisocyanate,
diphenylester diisocyanate, 2,4-cyclohexane diisocyanate,
2,3-cyclohexane diisocyanate, 1-methyl 2,4-cyclohexyl diisocyanate,
1-methyl 2,6-cyclohexyl diisocyanate, bis-(isocyanate cyclohexyl)
methane, 2,4,6-toluene triisocyanate, 2,4,4-diphenylether
triisocyanate, polymethylene-polyphenyl-polyisocyanates, methylene
diphenyl diisocyanate, triphenylmethane triisocyanate,
3,3'ditolylene-4,4-diisocyanate, 4,4'-methylenebis (2-methyl-phenyl
isocyanate), hexamethylene diisocyanate, 1,3-cyclohexylene
diisocyanate, 1,2-cyclohexylene diisocyanate and their mixtures. In
a preferred embodiment the compound containing isocyanate groups is
4,4-diphenylmethane-diisocyanate.
[0167] As far as the compounds having two and/or multiple
functional groups including peroxide groups are concerned, these
are preferably selected from benzoyl peroxide, lauroyl peroxide,
isononanoyl peroxide, di-(t-butylperoxyisopropyl)benzene, t-butyl
peroxide, dicumyl peroxide,
alpha,alpha-di(t-butylperoxy)diisopropylbenzene,
2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butyl cumyl peroxide,
di-t-butylperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hex-3-yne,
di(4-t-butylcyclohexyl)peroxy dicarbonate, dicetyl
peroxydicarbonate, dimyristyl peroxydicarbonate,
3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane,
di(2-ethylhexyl) peroxydicarbonate and mixtures thereof.
[0168] The compounds having two and/or multiple functional groups
including carbodiimide groups which are preferably used in the
composition according to this invention are selected from
poly(cyclooctylene carbodiimide), poly(1,4-dimethylencyclohexylene
carbodiimide), poly(cyclohexylene carbodiimide), poly(ethylene
carbodiimide), poly(butylene carbodiimide), poly(isobutylene
carbodiimide), poly(nonylene carbodiimide), poly(dodecylene
carbodiimide), poly(neopentylene carbodiimide),
poly(1,4-dimethylene phenylene carbodiimide),
poly(2,2',6,6'-tetraisopropyldiphenylene carbodiimide)
(Stabaxol.RTM. D), poly(2,4,6-triisopropyl-1,3-phenylene
carbodiimide) (Stabaxol.RTM. P-100), poly(2,6
diisopropyl-1,3-phenylene carbodiimide) (Stabaxol.RTM. P),
poly(tolyl carbodiimide), poly(4,4'-diphenylmethane carbodiimide),
poly(3,3'-dimethyl-4,4'-biphenylene carbodiimide), poly(p-phenylene
carbodiimide), poly(m-phenylene carbodiimide),
poly(3,3'-dimethyl-4,4'-diphenylmethane carbodiimide),
poly(naphthylene carbodiimide), poly(isophorone carbodiimide),
poly(cumene carbodiimide), p-phenylene bis(ethylcarbodiimide),
1,6-hexamethylene bis(ethylcarbodiimide), 1,8-octamethylene
bis(ethylcarbodiimide), 1,10-decamethylene bis(ethylcarbodiimide),
1,12 dodecamethylene bis(ethylcarbodiimide) and mixtures
thereof.
[0169] Examples of compounds having two and multiple functional
groups including epoxy groups which may advantageously be used in
the composition according to this invention are all the
polyepoxides from epoxidated oils and/or from
styrene-glycidylether-methylmethacrylate or
glycidylether-methylmethacrylate, included within a range of
molecular weights between 1000 and 10000 and having an epoxide
number per molecule within the range 1 to 30 and preferably between
5 and 25, the selected epoxides in the group comprising:
diethyleneglycol diglycidylether, polyethyleneglycol diglycidyl
ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether,
1,2-epoxybutane, polyglycerol polyglycidyl ether, isoprene
diepoxide, and cycloaliphatic diepoxides, 1,4-cyclohaxanedimethanol
diglycidyl ether, glycidyl 2-methylphenyl ether, glycerol
propoxylatotriglycidyl ether, 1,4-butanediol diglycidyl ether,
sorbitol polyglycidyl ether, glycerol diglycidyl ether,
tetraglycidyl ethers of meta-xylenediamine and diglycidyl ether or
bisphenol A and mixtures thereof.
[0170] Together with the compounds having two and multiple
functional groups including isocyanate, peroxide, carbodiimide,
isocyanurate, oxazoline, epoxy, anhydride and divinylether groups
such as for example those described above, catalysts may also be
used to raise the reactivity of the reactive groups. In the case of
the polyepoxides, salts of fatty acids, even more preferably
calcium and zinc stearates, may preferably be used.
[0171] In a particularly preferred embodiment of the invention the
cross-linking agent and/or chain extender for the composition in
layer B comprises compounds including isocyanate groups, preferably
4,4-diphenylmethane-diisocyanate, and/or containing carbodiimide
groups, and/or containing epoxy groups, preferably of the
styrene-glycidylether-methylmethacrylate type.
[0172] In layer B, in addition to component i.-v. mentioned above,
one or more other components may also advantageously be present. In
this case layer B comprises a composition comprising the components
i.-v. and preferably one or more polymers which are not the same as
components i., ii. and iii., of synthetic or natural origin, which
may or may not be biodegradable, together with possibly one or more
other components.
[0173] As far as the polymers which are not the same as components
i., ii. and iii., of synthetic or natural origin, which may or may
not be biodegradable, are concerned, these are advantageously
selected from the group comprising vinyl polymers, diacid diol
polyesters which are not the same as polyester i., polyamides,
polyurethanes, polyethers, polyureas, polycarbonates and mixtures
thereof.
[0174] Among the vinyl polymers those preferred are polyethylene,
polypropylene, their copolymers, polyvinyl alcohol, polyvinyl
acetate, polyethylvinyl acetate and polyethylene vinyl alcohol,
polystyrene, chlorinated vinyl polymers, polyacrylates.
[0175] Among the chlorinated vinyl polymers, those which are
intended to be included here, in addition to polyvinyl chloride are
polyvinylidene chloride, polyethylene chloride, poly(vinyl
chloride-vinyl acetate), poly(vinyl chloride-ethylene), poly(vinyl
chloride-propylene), poly(vinyl chloride-styrene), poly(vinyl
chloride-isobutylene) and copolymers in which polyvinyl chloride
represents more than 50% by moles. The said polymers may be random,
block or alternating copolymers.
[0176] As far as the polyamides in the composition according to
this invention are concerned, these are preferably selected from
the group comprising polyamide 6 and 6,6, polyamide 9 and 9,9,
polyamide 10 and 10,10, polyamide 11 and 11,11, polyamide 12 and
12,12 and their combinations of the 6/9, 6/10, 6/11 and 6/12 type,
their mixtures and both random and block copolymers.
[0177] Preferably the polycarbonates of the composition according
to this invention are selected from the group comprising
polyalkylene carbonates, more preferably polyethylene carbonates,
polypropylene carbonates, polybutylene carbonates, their mixtures
and random and block copolymers.
[0178] Among the polyethers, those preferred are those selected
from the group consisting of polyethylene glycols, polypropylene
glycols, polybutylene glycols, their copolymers and their mixtures
having molecular weights from 70000 to 500000.
[0179] As far as the diacid diol polyesters which are not the same
as the polyester i. in layer B are concerned, these preferably
comprise: [0180] i) a dicarboxylic component comprising, with
respect to the total dicarboxylic component: [0181] i1) 20-100% by
moles of units deriving from at least one aromatic dicarboxylic
acid, [0182] i2) 0-80% by moles of units deriving from at least one
saturated aliphatic dicarboxylic acid, [0183] i3) 0-5% by moles of
units deriving from at least one unsaturated aliphatic dicarboxylic
acid; [0184] j) a diol component comprising, with respect to the
total diol component: [0185] j1) 95-100% by moles of units deriving
from at least one saturated aliphatic diol; [0186] j2) 0-5% by
moles of units deriving from at least one unsaturated aliphatic
diol.
[0187] Preferably aromatic dicarboxylic acids i1, saturated
aliphatic dicarboxylic acids i2, unsaturated aliphatic dicarboxylic
acids i3, saturated aliphatic diols j1 and unsaturated aliphatic
diols j2 for the said polyesters are selected from those described
above for the polyester i in layer B according to this
invention.
[0188] In addition to the abovementioned components the composition
in layer B preferably also comprises at least one other component
selected from the group consisting of plasticisers, UV stabilisers,
lubricants, nucleating agents, surfactants, antistatic agents,
pigments, flame-retardant agents, compatibilising agents, lignin,
organic acids, antioxidants, anti-mould agents, waxes, process
coadjuvants and polymer components preferably selected from the
group consisting of vinyl polymers, diacid diol polyesters which
are not the aliphatic-aromatic polyesters described above,
polyamides, polyurethanes, polyethers, polyureas or
polycarbonates.
[0189] As far as the plasticisers are concerned, there are
preferably present in the composition of layer B according to this
invention, in addition to the plasticisers preferably used for
preparation of the destructured starch described above, one or more
plasticisers selected from the group consisting of phthalates, such
as for example diisononyl phthalate, trimellitates, such as for
example esters of trimellitic acid with C.sub.4-C.sub.20
monoalcohols preferably selected from the group consisting of
n-octanol and n-decanol, and aliphatic esters having the following
structure:
R.sub.1--O--C(O)--R.sub.4--C(O)--[--O--R.sub.2--O--C(O)--R.sub.5--C(O)---
].sub.m--O--R.sub.3
[0190] in which: [0191] R.sub.1 is selected from one or more groups
comprising H, linear and branched saturated and unsaturated alkyl
residues of the C.sub.1-C.sub.24 type, polyol residues esterified
with C.sub.1-C.sub.24 monocarboxylic acids; [0192] R.sub.2
comprises --CH.sub.2--C(CH.sub.3).sub.2--CH.sub.2-- and
C.sub.2-C.sub.8 alkylene groups, and comprises at least 50% by
moles of the said --CH.sub.2--C(CH.sub.3).sub.2--CH.sub.2-- groups;
[0193] R.sub.3 is selected from one or more groups comprising H,
linear and branched saturated and unsaturated alkyl residues of the
C.sub.1-C.sub.24 type, polyol residues esterified with
C.sub.1-C.sub.24 monocarboxylic acids; [0194] R.sub.4 and R.sub.5
are the same or different, comprise one or more C.sub.2-C.sub.22,
preferably C.sub.2-C.sub.11, more preferably C.sub.4-C.sub.9
alkylenes, and comprise at least 50% by moles of C.sub.7
alkylenes.
[0195] m is a number of between 1 and 20, preferably 2-10, more
preferably 3-7. Preferably, in the said esters at least one of the
groups R.sub.1 and/or R.sub.3 comprises, preferably in quantities
.gtoreq.10% by moles, more preferably .gtoreq.20%, even more
preferably .gtoreq.25% by moles with respect to the total quantity
of R.sub.1 and/or R.sub.3 groups, polyol residues esterified with
at least one C.sub.1-C.sub.24 monocarboxylic acid selected from the
group consisting of stearic acid, palmitic acid, 9-ketostearic
acid, 10-ketostearic acid and mixtures thereof. Examples of
aliphatic esters of this type are described in Italian Patent
Application MI2014A000030 and in PCT Applications
PCT/EP2015/050336, PCT/EP2015/050338.
[0196] When present in layer B the selected plasticisers are
preferably present up to 10% by weight with respect to the total
weight of the composition of layer B itself.
[0197] The lubricants are preferably selected from esters and metal
salts of fatty acids such as for example zinc stearate, calcium
stearate, aluminium stearate and acetyl stearate. Preferably the
composition of layer B according to this invention comprises up to
1% by weight of lubricants, more preferably up to 0.5% by weight
with respect to the total weight of the composition of layer B.
[0198] Examples of nucleating agents include the sodium salt of
saccharine, calcium silicate, sodium benzoate, calcium titanate,
boron nitride, isotactic polypropylene, or low molecular weight
PLA. These additives are preferably added in quantities up to 10%
by weight and more preferably between 2 and 6% by weight with
respect to the total weight of the composition.
[0199] Pigments may also be added if necessary, for example
titanium dioxide, clays, copper phthalocyanine, silicates, iron
oxide and hydroxides, carbon black and magnesium oxide. These
additives are preferably added up to 10% by weight.
[0200] Preferably, the polyesters of the layers A and/or B of the
multilayer film according to the present invention comprise at
least 10% by moles of aromatic dicarboxylic acids and/or aliphatic
dicarboxylic acids and/or diols of renewable origin. According to
the present invention, the products that can be considered of
renewable origin are those obtained from sources that, by their
very nature, are regenerable and inexhaustible on the time scale of
human life and the use of which consequently does not negatively
affect the availability of natural resources for future
generations. Examples of monomers of renewable origin are sebacic
acid, succinic acid, 2,5-furandicarboxylic acid, azelaic acid,
1,4-butanediol.
[0201] The multilayer film according to this invention comprises at
least one layer A and at least one layer B, preferably
characterised by a mutual relationship selected from A/B and A/B/A,
wherein the layer A and layer B are different from each other. The
multilayer film according to this invention may advantageously
comprise one or more layers A and one or more layers B, as well as
further layers, such as for example tie layers or barrier layers,
or metal films. In the multilayer film according to this invention
the ratio between the totality of layers A and the totality of
layers B is between 0.05 and 1.2. Preferably, in the multilayer
film according to this invention the ratio between the totality of
layers A and the totality of layers B is between 0.1 and 0.6. The
multilayer film according to this invention with an arrangement of
the layers of the A/B and preferably A/B/A type having a total
thickness in which the sum of the thicknesses of the A layers is
less than the thickness of the B layers, preferably less than B/2,
and more preferably less than B/3. The multilayer film according to
this invention advantageously has a total thickness of less than 50
microns, more preferably less than 15 microns, even more preferably
less than 13 microns.
[0202] The thickness of the layers can advantageously be measured
using the electron microscope on the fracture surface in liquid
nitrogen.
[0203] Further layers, arranged in an intermediate position with
respect to layers A and B (arrangement A/C/B, where C is a further
layer) or a non-intermediate position (arrangement A/B/C or C/A/B,
where C is a further layer) may also be present however.
[0204] The multilayer film according to this invention may be
produced according to any of those processes known in the art,
through for example a coextrusion, coating/spreading or lamination
process. In a preferred embodiment the multilayer film according to
this invention can be obtained through a coextrusion process,
preferably associated with a bubble film-forming process.
[0205] The equipment and specific process conditions, for example
for coextrusion and film-forming, for the production of multilayer
film according to this invention depend on the composition and
number of layers in which it is intended to produce the multilayer
film. Thanks to the specific combination of components and layers
the multilayer film according to this invention has the
characteristic that it allows optimum balancing between high level
biodegradation properties, mechanical properties, in particular a
high elastic modulus, and appreciable optical transparency
properties. This renders it particularly suitable for the
production of an extensive range of articles such as for example
packaging of various kinds, in particular bags for carrying of
goods and bags for food packaging such as bags for fruit and
vegetables comprising the said multilayer film.
[0206] As far as optical properties are concerned, transmittance
values of more than 90%, more preferably more than 91%, Haze values
of less than 65%, more preferably less than 55% and clarity over
20%, more preferably over 40% (measured according to standard ASTM
D1003), which allow the multilayer film according to this invention
to be particularly suitable for the applications mentioned above,
are particularly preferred.
[0207] The multilayer film according to the present invention is
biodegradable under home composting conditions according to
UNI11355. Preferably, the said multilayer film is biodegradable
under home composting conditions according to UNI1135, when
characterized by a total thickness of less than 15 microns,
preferably less than 13 microns.
[0208] The multilayer film according to the present invention finds
application in the production of mulching films thanks to their
high degree of disintegration at low temperatures, accompanied by
strong mechanical properties, being therefore capable of
effectively performing their action of protecting the ground, for
example impeding the growth of weeds and reducing water
consumption, without the need to be removed after use.
[0209] Preferably, disintegration of said mulching films comprising
the composition according to the present invention takes place in
the ground, at temperatures of 28.degree. C..+-.2, and the degree
of disintegration could be determined visibly through periodical
observations. Preferably, the multilayer film according to the
present invention will no longer be visible after 180 days.
[0210] This invention will now be illustrated on the basis of a
number of examples which are not intended to be limiting
thereupon.
EXAMPLE 1
Two-Layer Film Having an A/B Arrangement
[0211] Preparation of Composition A (layer A): 29.7 kg/h
poly(butylene adipate-co-butylene terephthalate), having a
terephthalic acid content of 47.5% by moles with respect to the
total dicarboxylic component, MFR 11 g/10 min (at 190.degree. C.,
2.16 kg) and acidity 50 meq/kg, 9.1 kg/h of Ingeo 3251D polylactic
acid ("PLA"), MFR 58 g/10 min (at 190.degree. C., 2.16 kg), 1.0
kg/h of masterbatch comprising 10% by weight of Joncryl ADR4368CS
(styrene-glycidylether-methylmethacrylate copolymer) and 90% of
Ingeo 4043D polylactic acid ("PLA"), 0.2 kg/h of masterbatch
comprising 10% Crodamide SR Bead manufactured by Croda and 90% of
poly(butylene adipate-co-butylene terephthalate) were fed to an OMC
EBV60/36 twin screw extruder operating under the following
conditions:
[0212] Screw diameter (D)=58 mm;
[0213] L/D=36;
[0214] Screw rotation speed=140 rpm;
[0215] Thermal profile=60-150-180-210.times.4-150.times.2.degree.
C.;
[0216] Throughput: 40 kg/h;
[0217] Vacuum degassing in zone 8 out of 10.
[0218] The granules so obtained had an MFR (190.degree. C., 2.16 kg
in accordance with standard ISO 1133-1 "Plastics--determination of
the melt mass-flow rate (MFR) and melt volume flow rate (MVR) of
thermoplastics--Part 1: Standard method") of 7 g/10 minutes.
Preparation of Composition B (layer B): 28.3 kg/h of poly(butylene
adipate-co-butylene azelate-co-butylene terephthalate) having an
azelaic acid content of 30% by moles with respect to the sum of
adipic acid and azelaic acid, and a terephthalic acid content of
48.3% by moles with respect to the total for the dicarboxylic
component, MFR 5 g/10 min (at 190.degree. C., 2.16 kg) and acidity
47 meq/kg, 1.4 kg/h of Ingeo 4043D polylactic acid ("PLA"), MFR 2.7
g/10 min (at 190.degree. C., 2.16 kg), 16 kg/h of thermoplastic
maize starch, 0.1 kg/h of Almatex PD-4440 produced by the Anderson
Development Company, 0.1 kg/h of Crodamide ER microbead
manufactured by Croda and 0.1 kg/h of Carbodilite HMV15CA
manufactured by Nisshinbo Chemical Inc. were fed to an OMC EBV60/36
model twin screw extruder operating under the following
conditions:
[0219] Screw diameter (D)=58 mm;
[0220] L/D=36;
[0221] Screw rotation speed=160 rpm;
[0222] Thermal profile=60-150-180-210.times.4-150.times.2.degree.
C.;
[0223] Throughput: 46.1 kg/h;
[0224] Vacuum degassing in zone 8 out of 10.
[0225] The granules so obtained had an MFR (160.degree. C., 5 kg in
accordance with standard ISO 1133-1 "Plastics--determination of the
melt mass-flow rate (MFR) and melt volume flow rate (MVR) of
thermoplastics--Part 1: Standard method") of 2.4 g/10 minutes.
[0226] Composition A and Composition B were then fed simultaneously
to a coextruder to form a two-layer blown film having an A/B
arrangement. For this purpose Composition A was fed at a throughput
of 3.3 kg/h to an extruder with a screw diameter of 35 mm and an
L/D of 30 operating at 13 rpm with a 100-170.times.4 thermal
profile. In parallel Composition B was fed through two extruders,
the first characterised by a screw diameter of 35 mm with an L/D of
30 operating at 12 rpm with a 80-154.times.4 thermal profile
operating at 3.3 kg/h and a second characterised by a screw
diameter of 40 mm with an L/D of 30 operating at 74 rpm with an
80-145.times.4 thermal profile and a throughput of 28.3 kg/h. Once
molten the two compositions were merged in the coextrusion-blowing
head having a gap of 0.9 mm and an L/D 9 set at 170.degree. C.,
feeding the multilayer structure to a film-forming process
operating with a blowing ratio of 4.5 and a stretch ratio of
20.2.
[0227] The film so obtained (total 10 microns, 10% layer A, 90%
layer B) was then characterised in terms of mechanical and optical
properties (Table 1).
EXAMPLE 2
Two-Layer Film Having an A/B/A Arrangement
[0228] Composition A and Composition B according to Example 1 was
simultaneously fed to a coextruder to form a three-layer blown film
having an A/B/A arrangement. With this object Composition A was fed
with a throughput of 3.3 kg/h to a first extruder having a screw
diameter of 35 mm with an L/D of 30 operating at 14 rpm with a
100-170.times.4 thermal profile and with a throughput of 3.3 kg/h
to a second extruder characterised by a screw diameter of 35 mm
with an L/D of 30 operating at 13 rpm with a 100-170.times.4
thermal profile. Composition B was fed at 28.3 kg/h to an extruder
having a screw diameter of 40 mm with an L/D of 30 operating at 74
rpm with a 80-154.times.4 thermal profile. Once molten the two
compositions were merged in a coextrusion-blowing head with a gap
of 0.9 mm and an L/D of 9 set at 170.degree. C., feeding the
multilayer structure to a film-forming process operating with a
blowing ratio of 4.5 and a stretch ratio of 20.2.
[0229] The film so obtained (total 10 microns, 20% layer A, evenly
distributed between the two layers, 80% layer B) was then
characterised in terms of mechanical and optical properties (Table
1).
EXAMPLE 3
(Comparative) Preparation of a Monolayer Film Comprising
Composition B
[0230] Composition B according to Example 1 was simultaneously fed
to a coextruder to form a monolayer blown film having an B/B/B
arrangement. With this object Composition B was fed with a
throughput of 2.8 kg/h to a first extruder having a screw diameter
of 35 mm with an L/D of 30 operating at 18 rpm with a
100-145.times.4 thermal profile and with a throughput of 24.3 kg/h
to a second extruder characterised by a screw diameter of 40 mm
with an L/D of 30 operating at 63 rpm with a 80-145.times.4 thermal
profile and with a throughput of 2.8 kg/h to a third extruder
characterised by a screw diameter of 35 mm with an L/D of 30
operating at 18 rpm with a 100-145.times.4. The coextrusion-blowing
head has a gap of 0.9 mm and an L/D of 9 set at 145.degree. C.,
feeding the monolayer structure to a film-forming process operating
with a blowing ratio of 4.5 and a stretch ratio of 20.2.
[0231] The film so obtained (total 10 microns, 100% composition B)
was then characterised in terms of mechanical and optical
properties (Table 1).
EXAMPLE 4
Two-Layer Film Having an A/B/A Arrangement
[0232] Preparation of Composition A (layer A): 31.4 kg/h of
poly(butylene adipate-co-butylene terephthalate) having a
terephthalic acid content of 47.5% by moles with respect to the
total dicarboxylic component, MFR 11 g/10 min (at 190.degree. C.,
2.16 kg) and acidity 50 meq/kg, 7.6 kg/h of Ingeo 3251D polylactic
acid ("PLA"), MFR 58 g/10 min (at 190.degree. C., 2.16 kg), 0.8
kg/h of masterbatch comprising 10% by weight of Joncryl ADR4368CS
(styrene-glycidylether-methylmethacrylate copolymer) and 90% of
Ingeo 4043D polylactic acid ("PLA"), 0.2 kg/h of masterbatch
comprising 10% Crodamide SR Bead manufactured by Croda and 90% of
poly(butylene adipate-co-butylene terephthalate) were fed to an OMC
EBV60/36 model twin screw extruder operating under the conditions
specified for layer A in Example 1.
[0233] The granules so obtained had an MFR (190.degree. C., 2.16 kg
in accordance with standard ISO 1133-1) of 7.5 g/10 minutes.
[0234] Composition A according to Example 4 and Composition B
according to Example 1 were simultaneously fed to a coextruder to
form a three-layer blown film having an A/B/A arrangement. With
this object Composition A was fed with a throughput of 2.9 kg/h to
a first extruder having a screw diameter of 35 mm with an L/D of 30
operating at 11 rpm with a 60-170.times.4 thermal profile and with
a throughput of 2.9 kg/h to a second extruder characterised by a
screw diameter of 35 mm with an L/D of 30 operating at 11 rpm with
a 60-170.times.4 thermal profile. Composition B was fed at 24.2
kg/h to an extruder having a screw diameter of 40 mm with an L/D of
30 operating at 64 rpm with a 80-145.times.4 thermal profile. Once
molten the two compositions were merged in a coextrusion-blowing
head with a gap of 0.9 mm and an L/D 9 set to 170.degree. C.,
feeding the multilayer structure to a film-forming process
operating with a blowing ratio of 4.5 and a stretch ratio of
20.2.
[0235] The film so obtained (total 10 microns, 20% layer A evenly
distributed between the two layers, 80% layer B) was then
characterised in terms of mechanical and optical properties (Table
1).
EXAMPLE 5
Two-Layer Film Having an A/B/A Arrangement
[0236] Preparation of Composition A (layer A): 16 Kg/h
poly(butylene sebacate), MFR 3.7 g/10 min (at 150.degree. C., 2.16
kg) and acidity 25 meq/Kg, 20 kg/h poly(butylene
adipate-co-butylene terephthalate), having a terephthalic acid
content of 47.5% by moles with respect to the total dicarboxylic
component, MFR 5.1 g/10 min (at 190.degree. C., 2.16 kg) and
acidity 37 meq/Kg, 4 kg/h of Ingeo 4043D polylactic acid ("PLA"),
MFR 2.5 g/10 min (at 190.degree. C., 2.16 kg), 0.1 kg/h of
Crodamide ER microbead manufactured by Croda were fed to an OMC
EBV60/36 twin screw extruder operating under the following
conditions:
[0237] Screw diameter (D)=58 mm;
[0238] L/D=36;
[0239] Screw rotation speed=160 rpm;
[0240] Thermal profile=60-120-160.times.5-150.times.2.degree.
C.;
[0241] Throughput: 40.1 kg/h;
[0242] Vacuum degassing in zone 8 out of 10.
[0243] The granules so obtained had an MFR (190.degree. C., 2.16 kg
in accordance with standard ISO 1133-1 "Plastics--determination of
the melt mass-flow rate (MFR) and melt volume flow rate (MVR) of
thermoplastics--Part 1: Standard method") of 6 g/10 minutes.
[0244] Composition A according to Example 5 and Composition B
according to Example 1 were then fed simultaneously to a coextruder
to form a three-layer blown film having an A/B/A arrangement. For
this purpose Composition A was fed at a throughput of 2.8 kg/h to
an extruder with a screw diameter of 35 mm and an L/D of 30
operating at 11 rpm with a 60-125.times.4 thermal profile.
Composition B was fed through an extruder characterised by a screw
diameter of 40 mm with an L/D of 30 operating at 66 rpm with a
80-145.times.4 thermal profile. Once molten the two compositions
were merged in the coextrusion-blowing head having a gap of 0.9 mm
and an L/D 9 set at 145.degree. C., feeding the multilayer
structure to a film-forming process operating with a blowing ratio
of 4.5 and a stretch ratio of 20.2.
[0245] The film so obtained (total 10 microns, 20% layer A, 80%
layer B) was then characterised in terms of mechanical and optical
properties (Table 1).
EXAMPLE 6
Two-Layer Film Having an A/B/A Arrangement
[0246] Preparation of Composition A (layer A): poly(butylene
succinate-co-butylene azelate) having an azelaic acid content of
25% by moles with respect to the total dicarboxylic component, MFR
6 g/10 min (at 190.degree. C., 2.16 kg) and acidity 46 meq/kg.
[0247] Composition A according to Example 6 and Composition B
according to Example 1 were simultaneously fed to a coextruder to
form a three-layer blown film having an A/B/A arrangement. With
this object Composition A was fed with a throughput of 2.8 kg/h to
a first extruder having a screw diameter of 35 mm with an L/D of 30
operating at 12 rpm with a 60-120.times.4 thermal profile and with
a throughput of 2.8 kg/h to a second extruder characterised by a
screw diameter of 35 mm with an L/D of 30 operating at 12 rpm with
a 60-120.times.4 thermal profile. Composition B was fed at 24.3
kg/h to an extruder having a screw diameter of 40 mm with an L/D of
30 operating at 63 rpm with a 80-145.times.4 thermal profile. Once
molten the two compositions were merged in a coextrusion-blowing
head with a gap of 0.9 mm and an L/D 9 set to 145.degree. C.,
feeding the multilayer structure to a film-forming process
operating with a blowing ratio of 4.5 and a stretch ratio of
16.8.
[0248] The film so obtained (total 12 microns, 20% layer A evenly
distributed between the two layers, 80% layer B) was then
characterised in terms of mechanical and optical properties (Table
1).
EXAMPLE 7
Two-Layer Film Having an A/B/A Arrangement
[0249] Preparation of Composition A (layer A): poly(butylene
adipate-co-butylene terephthalate) having a terephthalic acid
content of 47.5% by moles with respect to the total dicarboxylic
component, MFR 3.9 g/10 min (at 190.degree. C., 2.16 kg) and
acidity 33 meq/kg. Composition A according to Example 7 and
Composition B according to Example 1 were simultaneously fed to a
coextruder to form a three-layer blown film having an A/B/A
arrangement. With this object Composition A was fed with a
throughput of 2.8 kg/h to a first extruder having a screw diameter
of 35 mm with an L/D of 30 operating at 16 rpm with a
60-145.times.4 thermal profile and with a throughput of 2.8 kg/h to
a second extruder characterised by a screw diameter of 35 mm with
an L/D of 30 operating at 16 rpm with a 60-145.times.4 thermal
profile. Composition B was fed at 24.3 kg/h to an extruder having a
screw diameter of 40 mm with an L/D of 30 operating at 63 rpm with
a 80-145.times.4 thermal profile. Once molten the two compositions
were merged in a coextrusion-blowing head with a gap of 0.9 mm and
an L/D 9 set to 145.degree. C., feeding the multilayer structure to
a film-forming process operating with a blowing ratio of 3.6 and a
stretch ratio of 25.2.
[0250] The film so obtained (total 10 microns, 20% layer A evenly
distributed between the two layers, 80% layer B) was then
characterised in terms of mechanical and optical properties (Table
1).
TABLE-US-00001 TABLE 1 FILM TENSILE Elmendorf tear STRENGTH ASTM
D822 ASTM D1922 OPTICAL PROPERTIES (23.degree. C. 55% RH - Vo 50
mm/min) (23.degree. C. - 55% RH) ASTM D1003 .sigma..sub.b
.epsilon..sub.b E .sigma..sub.b .epsilon..sub.b E TRASM. HAZE
CLARITY (MPa) (%) (MPa) (MPa) (%) (MPa) % % % Example 1 24 874 334
2559 MD 107 92 88 27 (10 micron) TD 40 Example 2 25 320 355 3003 MD
112 92 38 60 (10 micron) TD 40 Example 3 30 315 243 3547 MD 161 92
98 8 comparative TD 309 (10 micron) Example 4 32 351 386 4182 MD
127 92 31 61 (10 micron) TD 78 Example 5 30 291 332 3425 MD 157 93
61 31 (10 micron) TD 214 Example 6 28 335 243 3550 MD 173 93 46 34
(12 micron) TD 203 Example 7 44 331 298 5254 MD 98 92 46 41 (10
micron) TD 258
* * * * *