AU728971B2

AU728971B2 - Compostable and thermoplastically processable foams

Info

Publication number: AU728971B2
Application number: AU25092/97A
Authority: AU
Inventors: Ernst Grigat; Hanns-Peter Muller; Wolfgang Schulz-Schlitte
Original assignee: Bayer AG
Current assignee: Bayer AG
Priority date: 1996-04-18
Filing date: 1997-04-07
Publication date: 2001-01-25
Anticipated expiration: 2017-04-07
Also published as: NZ332356A; CN1216558A; AU2509297A; JP2000508698A; WO1997040091A3; WO1997040091A2; EP0894113A2; CA2251932A1; DE19615356A1

Description

Le A 31 771-PCT -1- Compostable and thermoplastically processable foams Foamed, thermoplastically processable plastics are known (c.f 26mpp Chemielexikon under "Schaumkunststoffe", volume 5, 9 th edition, Thieme Verlag 1992). They are obtained inter alia by the use of blowing agents (c.f Rompp Chemielexikon under "Bliihmittel", volume 1, 9 th edition, Thieme Verlag 1990).

It may be considered that there is a need to produce completely compostable articles resistant to water and water vapour having a low density.

The present invention accordingly relates to foamed mouldings produced from polymers selected from -the group of aliphatic or partially aromatic polyesters, thermoplastic aliphatic or partially aromatic polyesterurethanes, aliphatic or aliphaticaromatic polyestercarbonates and aliphatic polyesteramides, which are mixed with blowing agents and thermoplastically processed.

The present invention furthermore relates to a process for the production of the articles e.oo according to the invention.

20 2 The present invention furthermore relates to the use of certain completely compostable polymers resistant to water and water vapour for the production of foamed mouldings.

S

The following polymers are suitable: Aliphatic or partially aromatic polyesters prepared from A) aliphatic difunctional alcohols, preferably linear C2-Cio dialcohols, such as for example ethanediol, butanediol, hexanediol, particularly preferably butanediol Le A 31 771 -2and/or optionally cycloaliphatic difunctional alcohols, preferably having C 5

-C

6 C atoms in the cycloaliphatic ring, such as for example cyclohexanedimethanol and/or, partially or entirely instead of the diols, monomeric or oligomeric polyols based on ethylene glycol, propylene glycol, tetrahydrofuran or copolymers thereof having molecular weights of up to 4000, preferably of up to 1000, and/or optionally small quantities of branched, difunctional alcohols, preferably C 3

-C

12 alkyldiols, such as for example neopentyl glycol and additionally optionally small quantities of more highly functional alcohols, preferably C 3

-C

1 2 alkylpolyols, such as for example 1,2,3-propanetriol or trimethylolpropane and from aliphatic, difunctional acids, preferably C 2

-C

1 2 alkyldicarboxylic acids, such as for example and preferably succinic acid or adipic acid and/or optionally aromatic difunctional acids, such as for example terephthalic acid or isophthalic acid or naphthalenedicarboxylic acid and additionally optionally small quantities of more highly functional acids, such as for example trimellitic acid or B) from acid- and alcohol-functionalised structural units, preferably having 2 to 12 C atoms in the alkyl chain, for example hydroxybutyric acid or hydroxyvaleric acid or lactic acid, or the derivatives thereof, for example E-capro- 2 0 lactone or dilactide, or a mixture and/or a copolymer of A and B, wherein the aromatic acids constitute a fraction of no more than 50 relative to all the acids.

All the acids may also be used in the form of derivatives, such as for example acid chlorides or esters, both as monomeric and as oligomeric esters; Aliphatic or partially aromatic polyesterurethanes prepared from Le A 31 771 -3- C) aliphatic difunctional alcohols, preferably linear C 2

-C

l o dialcohols, such as for example ethanediol, butanediol, hexanediol, particularly preferably butanediol and/or optionally cycloaliphatic difunctional alcohols, preferably having a Cs-

C

6 cycloaliphatic ring, such as for example cyclohexanedimethanol and/or, partially or entirely instead of the diols, monomeric or oligomeric polyols based on ethylene glycol, propylene glycol, tetrahydrofuran or copolymers thereof having molecular weights of up to 4000, preferably of up to 1000, and/or optionally small quantities of branched, difunctional alcohols, preferably C 3

-C

1 2 alkyldiols, such as for example neopentyl glycol and additionally optionally small quantities of more highly functional alcohols, preferably C 3

-C

1 2 alkyldicarboxylic acids, such as for example and preferably succinic acid or adipic acid and/or optionally aromatic difunctional acids, such as for example terephthalic acid or isophthalic acid or naphthalenedicarboxylic acid and additionally optionally small quantities of more highly functional acids, such as for example trimellitic acid or D) from acid- and alcohol-functionalised structural units, preferably having 2 to 12 C atoms in the alkyl chain, for example hydroxybutyric acid or hydroxyvaleric acid or lactic acid, or the derivatives thereof, for example E-caprolactone or dilactide, or a mixture and/or a copolymer of C and D, wherein the aromatic acids constitute a fraction of no more than 50 relative to all the acids.

All the acids may also be used in the form of derivatives, such as for example acid chlorides or esters, both as monomeric and as oligomeric esters; Le A 31 771 -4- E) from the reaction product of C and/or D with aliphatic and/or cycloaliphatic difunctional and additionally optionally more highly functional isocyanates, preferably having 1 to 12 C atoms or 5 to 8 C atoms in the case of cycloaliphatic isocyanates, for example tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, optionally additionally with linear and/or branched and/or cycloaliphatic difunctional and/or more highly functional alcohols, preferably C 3

-C

1 2 alkyldi- or polyols or 5 to 8 C atoms in the case of cycloaliphatic alcohols, for example ethanediol, hexanediol, butanediol, cyclohexanedimethanol, and/or optionally additionally with linear and/or branched and/or cycloaliphatic difunctional and/or more highly functional amines and/or aminoalcohols preferably having 2 to 12 C atoms in the alkyl chain, for example ethylenediamine or aminoethanol, and/or optionally further modified amines or alcohols, such as for example ethylenediaminoethanesulfonic acid, as the free acid or the salt, wherein the ester fraction C) and/or D) amounts to at least 75 relative to the sum of D) and wherein, in the polymer structure typical of polyurethanes optionally comprising soft segments C) and D) and hard segments a completely random distribution of the raw materials in the polymer is not to be expected; Aliphatic or aliphatic-aromatic polyestercarbonates prepared from F) aliphatic difunctional alcohols, preferably linear C 2

-C

10 dialcohols, such as for example ethanediol, butanediol, hexanediol, particularly preferably butanediol and/or optionally cycloaliphatic difunctional alcohols, preferably having 5 to 8 C atoms in the cycloaliphatic ring, such as for example cyclohexanedimethanol and/or, partially or entirely instead of the diols, monomeric or oligomeric polyols based on ethylene glycol, propylene glycol, tetrahydrofuran or copolymers thereof having molecular weights of up to 4000, preferably of up to 1000, and/or optionally small quantities of branched, difunctional alcohols, Spreferably C 3

-C

1 2 alkyldiols, such as for example neopentyl glycol and Le A 31 771 additionally optionally small quantities of more highly functional alcohols, preferably C 3

-C

1 2 alkyldicarboxylic acids, such as for example and preferably succinic acid or adipic acid and/or optionally aromatic difunctional acids, such as for example terephthalic acid or isophthalic acid or naphthalenedicarboxylic acid and additionally optionally small quantities of more highly functional acids, such as for example trimellitic acid or G) from acid- and alcohol-functionalised structural units, preferably having 2 to 12 C atoms in the alkyl chain, for example hydroxybutyric acid or hydroxyvaleric acid or lactic acid, or the derivatives thereof, for example E-caprolactone or dilactide, or a mixture and/or a copolymer ofF and G, wherein the aromatic acids constitute a fraction of no more than 50 relative to all the acids.

All the acids may also be used in the form of derivatives, such as for example acid chlorides or esters, both as monomeric and as oligomeric esters; H) a carbonate fraction which is produced from aromatic difunctional phenols, preferably bisphenol A, and carbonate donors, preferably phosgene, or a carbonate fraction which is produced from aliphatic carbonic acid esters or the derivatives thereof, such as chlorocarbonic acid esters or aliphatic carboxylic acids or the derivatives thereof, such as for example salts and carbonate donors, for example phosgene.

The ester fraction F) and/or G) must amount to at least 70 relative to the sum of S G) and H); Le A 31 771 -6- Aliphatic or partially aromatic polyesteramides prepared from I) aliphatic difunctional alcohols, preferably linear C 2

-C

1 0 dialcohols, such as for example ethanediol, butanediol, hexanediol, particularly preferably butanediol and/or optionally cycloaliphatic difunctional alcohols, preferably having 5 to 8 carbon atoms, such as for example cyclohexanedimethanol and/or, partially or entirely instead of the diols, monomeric or oligomeric polyols based on ethylene glycol, propylene glycol, tetrahydrofuran or copolymers thereof having molecular weights of up to 4000, preferably of up to 1000, and/or optionally small quantities of branched, difunctional alcohols, preferably C 3

C

1 2 alkylpolyols, such as for example 1,2,3-propanetriol or trimethylolpropane and from aliphatic, difunctional acids, preferably having 2 to 12 C atoms in the alkyl chain, such as for example and preferably succinic acid or adipic acid and/or optionally aromatic difunctional acids, such as for example terephthalic acid or isophthalic acid or naphthalenedicarboxylic acid and additionally optionally small quantities of more highly functional acids, such as for example trimellitic acid or K) from acid- and alcohol-functionalised structural units, preferably having 2 to 12 C atoms in the carbon chain, for example hydroxybutyric acid or hydroxyvaleric acid or lactic acid, or the derivatives thereof, for example E-caprolactone or dilactide, or a mixture and/or a copolymer of I) and K), wherein the aromatic acids constitute a fraction of no more than 50 relative to all the acids.

Le A 31 771 -7- All the acids may also be used in the form of derivatives, such as for example acid chlorides or esters, both as monomeric and as oligomeric esters; L) an amide fraction prepared from aliphatic and/or cycloaliphatic difunctional and/or optionally small quantities of branched difunctional amines, linear aliphatic C 2 -Co 0 diamines being preferred, and additionally optionally small quantities of more highly functional amines, hexamethylenediamine, isophoronediamine being preferred among the amines and hexamethylenediamine being particularly preferred, and from linear and/or cycloaliphatic difunctional acids, preferably having 2 to 12 C atoms in the alkyl chain or a Cs-

C

6 ring in the case of cycloaliphatic acids, preferably adipic acid and/or optionally small quantities of branched, difunctional and/or optionally aromatic difunctional acids, such as for example terephthalic acid or isophthalic acid or naphthalenedicarboxylic acid and additionally optionally small quantities of more highly functional acids, preferably having 2 to 10 C atoms or M) from an amide fraction prepared from acid- and amine-functionalised structural units, preferably having 4 to 20 C atoms in the cycloaliphatic chain, preferably 6 -laurolactam and E-caprolactam, particularly preferably E-caprolactam, or a mixture of L) and M) as the amide fraction.

The ester fraction I) and/or K) must amount to at least 30 relative to the sum of L) and The fraction by weight of the ester structures is preferably between 30 and 70%, the fraction of the amide structures between 70 and The biodegradable polyesteramides according to the invention may be synthesised both in accordance with the "polyamide method" by stoichiometric mixing of the starting components optionally with the addition of water and subsequent removal of O water from the reaction mixture and in accordance with the "polyester method" by stoichiometric mixing of the starting components together with the addition of an Le A 31 771 -8excess of diol with esterification of the acid groups and subsequent transesterification or transamidation of these esters. In this second case, the excess of diol is distilled off again together with the water. Synthesis in accordance with the described "polyester method" is preferred.

The polyesters, polyesterurethanes, polyestercarbonates or preferably polyesteramides according to the invention may furthermore contain 0.1 to 5 preferably 0.1 to 1 wt.% of branching agents. These branching agents may be, for example, trifunctional alcohols, such as trimethylolpropane or glycerol, tetrafunctional alcohols such as pentaerythritol, trifunctional carboxylic acids such as citric acid. The branching agents increase the melt viscosity of the polyesteramides according to the invention to such an extent that extrusion blow moulding is possible with these polymers. Biodegradation of these materials is not hindered as a consequence.

Polycondensation may furthermore be accelerated by the use of known catalysts.

Possible catalysts for accelerating polycondensation are not only known phosphorus compounds, which accelerate polyamide synthesis, and acidic or organometallic esterification catalysts, but also combinations of the two types.

Care must be taken to ensure that the catalysts have a negative effect neither on biodegradability or compostability nor on the quality of the resultant compost.

Polycondensation to yield polyesteramides may furthermore be influenced by the use of lysine, lysine derivatives or other amide branching products, such as for example aminoethylaminoethanol, which both accelerate condensation and give rise to branched products (c.f for example DE 38 31 709).

The completely compostable polyesterurethanes, polyesters, polyestercarbonates and polyesteramides according to the invention may be provided with fillers and reinforcing materials and/or with processing auxiliaries, such as for example nucleating auxiliaries, mould release auxiliaries or stabilisers, wherein care must be Le A 31 771 -9taken to ensure that complete compostability is not impaired or the remaining substances, for example mineral auxiliaries, are innocuous in the compost.

Fillers and reinforcing materials suitable according to the invention may be minerals, such as for example kaolin, chalk, gypsum (c or 13 modification), lime or talc or natural substances, such as for example starch or modified starch, cellulose or cellulose derivatives or cellulose products, wood flour or natural fibres, such as for example hemp, flax, rape or ramie.

The completely compostable polyesterurethanes, polyestercarbonates and polyesteramides according to the invention may also be mixed with further blend components, wherein care must be taken to ensure that complete compostability is not impaired or the remaining substances, for example mineral auxiliaries, are innocuous in the compost.

Blowing agents usable according to the invention may be substances which are gaseous under thermoplastic processing conditions, for example compounds which eliminate nitrogen, water or carbon dioxide, vaporisable compounds or reaction products of two or more compounds which are gaseous under thermoplastic processing conditions.

The group of blowing agents eliminating gaseous substances, for example nitrogen, water or carbon dioxide under thermoplastic processing conditions includes, for example, azo compounds, such as for example and preferably hydrazides, such as for example and particularly preferably toluenesulfonic acid hydrazide, or carbonates, such as for example calcium carbonate or sodium carbonate or preferably hydrogen carbonates, among these preferably sodium hydrogen carbonate, or mineral salts which eliminate water.

The group of blowing agents consisting of vaporisable compounds includes, for I example, pentane, cyclopentane or C 1 halogenated hydrocarbons.

Le A 31 771 The group of reaction products of two or more compounds, which are gaseous under thermoplastic processing conditions, includes for example and preferably mixtures of acids, among the acids preferably lactic acid, oxalic acid and particularly preferably citric acid, and CO 2 donors, such as for example carbonates and bicarbonates.

The blowing agents are generally used in a quantity of 0.1 to 30, preferably of 0.5 to particularly preferably of 1 to 8 relative to the entire mixture.

The present invention furthermore relates to a process for the production of the articles according to the invention, characterised in that the mixture of the completely compostable polymers resistant to water and water vapour according to the invention is mixed with the blowing agents and the mixture is thermoplastically processed.

Thermoplastic processing may comprise extrusion, for example to yield foamed profiles. Thermoplastic processing may also comprise injection moulding to yield foamed mouldings, such as for example dishes or cups. Thermoplastic processing may also comprise vigorous mixing below the foaming temperature, for example in a kneader, and subsequent heat treatment at above the foaming temperature to yield components, such as for example semi-finished products.

The present invention furthermore relates to the use of the completely compostable polymers resistant to water and water vapour according to the invention for the production of foamed mouldings.

Le A 31 771 11 Examples Example 1 A biodegradable polyesteramide comprising a 60 wt.% fraction of polycaprolactam and a 40 wt.% fraction of an ester of adipic acid and butanediol (relative solution viscosity: 2.5, measured on a 1 wt.% solution in meta-cresol at 200C) is extruded at 1450C with 5 wt.% (relative to the entire mixture) oftoluenesulfonic acid hydrazide. A foamed extrudate having a bulk density of 0.6 g/cm 3 is obtained.

Example 2 g of a biodegradable polyesteramide comprising a 60 wt.% fraction of polycaprolactam and a 40 wt.% fraction of an ester of adipic acid and butanediol (relative solution viscosity: 2.5, measured on a 1 wt.% solution in meta-cresol at 200C) are intimately mixed with 1 g of azodicarbonamide at 1500C in a kneader, transferred into an open, heat-resistant mould and then heated for 30 minutes at 2000C in an oven. A coarse-cell foam having a bulk density of 0.07 g/cm 3 is obtained.

Example 3 A biodegradable polyesteramide comprising a 60 wt.% fraction of polycaprolactam and a 40 wt.% fraction of an ester of adipic acid and butanediol (relative solution viscosity: 2.5, measured on a 1 wt.% solution in meta-cresol at 200C) is extruded at 1350C with 0.5 wt.% (relative to the entire mixture) of sodium hydrogen carbonate. A foamed extrudate having a bulk density of 0.7 g/cm 3 is obtained.

P:\WPDOCS\CRN\SPECI699980.spe.doc-3 1/08/00 -1la- Note: Amendments have been made to the claims which appear hereafter in order to further define the invention. These amendments are based on embodiments of the invention described herein. For integrity of the text and of the specification as filed, corresponding amendments have not been made to the text of the specification. Accordingly, it will be appreciated that the specification refers broadly to various aspects of the invention, which description encompasses the embodiments defined in the claims.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge in Australia.

p

Claims

1. Wo -12 The claims defining the invention are as follows: 1. Foamed mouldings produced from biodegradable polymers, which are mixed with blowing agents and optionally conventional additives and melt proc- essed, selected from the group of: Aliphatic or partially aromatic polyesteramides prepared from I) aliphatic difunctional alcohols and/or optionally cycloaliphatic di- functional alcohols and/or, partially or entirely instead of the diols, monomeric or oligomeric polyols based on ethylene glycol, propylene Le A 31 771-Foreign Countries 2& 7. 00 -13 glycol, tetrahydrofuran or copolymers thereof having molecular weights of up to 4000 and/or optionally small quantities of branched, difunctional alcohols and additionally small quantities of more highly functional alcohols and from aliphatic, difunctional acids and/or op- tionally aromatic difunctional acids and additionally optionally small quantities of more highly functional acids or K) from acid- and alcohol-functionalised structural units or the derivatives thereof, or a mixture and/or a copolymer of I) and K), wherein the aromatic acids constitute a fraction of no more than 50 wt.%, relative to all the acids; L) an amide fraction-prepared from aliphatic and/or cycloaliphatic di- functional and/or optionally small quantities of branched difunctional amines and additionally optionally small quantities of more highly functional amines and from linear and/or cycloaliphatic difunctional acids and/or optionally small quantities of branched, difunctional and/or optionally aromatic difunctional acids and additionally option- ally small quantities of more highly functional acids or M) from an amide fraction prepared from acid- and amine-functionalised structural units, or a mixture of L) and M) as the amide fraction, wherein the ester fraction I) and/or K) amounts to at least 30 relative to the sum of L) and and wherein all the acids may also be used in the form of derivatives, both as monomeric and as oligomeric esters. Le A 31 771-Foreign Countries -14

2. Foamed mouldings produced from biodegradable polymers, which are mixed with blowing agents and optionally conventional additives and melt proc- essed, selected from the group of: Aliphatic or partially aromatic polyesteramides prepared from I) aliphatic difunctional alcohols and/or optionally cycloaliphatic di- functional alcohols and/or, partially or entirely instead of the diols, monomeric or oligomeric polyols based on ethylene glycol, propylene glycol, tetrahydrofuran or copolymers thereof having molecular Le A 31 771-Foreign Countries 2 weights of up to 4000 and/or optionally small quantities of branched, difunctional alcohols and additionally small quantities of more highly functional alcohols and from aliphatic, difunctional acids and/or op- tionally aromatic difunctional acids and additionally optionally small quantities of more highly functional acids or K) from acid- and alcohol-functionalised structural units of the deriva- tives thereof, or a mixture and/or a copolymer of I) and K), wherein the aromatic acids constitute a fraction of no more than 50 wt.%, relative to all the acids; 15 L) an amide fraction-prepared from aliphatic and/or cycloaliphatic di- functional and/or optionally small quantities of branched difunctional amines and additionally optionally small quantities of more highly functional amines and from linear and/or cycloaliphatic difunctional ~acids and/or optionally small quantities of branched, difunctional 20 and/or optionally aromatic difunctional acids and additionally option- ally small quantities of more highly functional acids or M) from an amide fraction prepared from acid- and amine-functionalised structural units, or a mixture of L) and M) as the amide fraction, wherein the ester fraction I) and/or K) amounts to at least 30 relative to the sum of L) and M). Le A 31 771-Foreign Countries 2 7. -16

3. Process for the production of foamed mouldings according to claim 1 or claim 2, wherein the biodegradable polymers are mixed with the blowing agents and the mixture is melt processed.

4. Use of biodegradable polymers according to any one of claims 1 to 3 for the production of foamed mouldings using blowing agents. Foam mouldings produced from biodegradable polymers, a process for their production or the use of biodegradable polymers substantially as herein described with reference to the Examples. DATED this 31st day of August, 2000 BAYER ATIENGESELLSCHAFT 0• By its Patent Attorneys DAVIES COLLISON CAVE S t 0009 O*•O *AO 8OOO