EP0701581A1 - Traitement de polyesters - Google Patents

Traitement de polyesters

Info

Publication number
EP0701581A1
EP0701581A1 EP94917075A EP94917075A EP0701581A1 EP 0701581 A1 EP0701581 A1 EP 0701581A1 EP 94917075 A EP94917075 A EP 94917075A EP 94917075 A EP94917075 A EP 94917075A EP 0701581 A1 EP0701581 A1 EP 0701581A1
Authority
EP
European Patent Office
Prior art keywords
polyester
ageing
heat treated
process according
units
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP94917075A
Other languages
German (de)
English (en)
Inventor
John Jamieson Liggat
Gregory O'brien
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Monsanto Co
Original Assignee
Zeneca Ltd
Monsanto Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Zeneca Ltd, Monsanto Co filed Critical Zeneca Ltd
Publication of EP0701581A1 publication Critical patent/EP0701581A1/fr
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C71/00—After-treatment of articles without altering their shape; Apparatus therefor
    • B29C71/02—Thermal after-treatment
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
    • C08G63/88—Post-polymerisation treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2067/00—Use of polyesters or derivatives thereof, as moulding material

Definitions

  • THIS INVENTION relates to a polyester composition and in particular to such a composition containing biodegradable polyester and capable of producing shaped articles resistant to embrittlement. It has been disclosed by de Koning et a in Polymer 1992, 33,
  • polyester composition comprising at least one polyhydroxyalkanoate (PHA) and at least one plasticiser thereof, in which ageing has occurred, characterised
  • the polyester is restored to its original non-aged properties by a heat treatment, and (ii) subsequent ageing of the polyester is retarded as indicated by substantial improvement of at least one measurement indicative of ageing compared to non heat treated polyester of the same age.
  • the retardation of subsequent ageing may be indicated by substantial improvement of at least one measurement indicative of ageing compared to heat treated polyester of the same age without plasticiser.
  • a shaped article at least partly made from a polyester composition comprising at least one polyhydroxyalkanoate (PHA) and at least one plasticiser thereof, in which ageing has occurred, characterised in that (i) the shaped article is restored to its original non-aged properties by heating, and (ii) subsequent ageing of the polyester is retarded as indicated by substantial improvement of at least one measurement indicative of ageing compared to non heat treated polyester of the same age. Alternately the retardation of subsequent ageing may be indicated by substantial improvement of at least one measurement indicative of ageing compared to heat treated polyester of the same age without plasticiser.
  • PHA polyhydroxyalkanoate
  • At least partly made means having structural components made of PHA to such an extent that ageing of the PHA component ages the whole article.
  • PHA may be homogeneously mixed with other biodegradable polymers such as polylactides or polycaprolactone.
  • the minimum amount of PHBV is at least 30% w /w.
  • articles having PHA components linked to other components such as razors and toothbrushes, and articles made of a matrix of some other biodegradable (e.g. starch) or non-biodegradable polymer (e.g. polypropylene) with PHA inclusions, are within the invention.
  • the minimum amount of PHA is at least 30% w /w.
  • Substantial improvement means that the measurement indicative of ageing, for example, elongation to break, is improved by 50% or more, preferably 100% or more, compared to the heat treated aged polyester without plasticiser at the same age as the heat treated aged polyester with plasticiser, or alternately it can be compared to the non-heat treated polyester of the same age.
  • the "same age” means the same period of ageing after the heat treatment i.e. one month after initial preparation of the polyester for the non heat treated polyester is the equivalent age to one month after heat treatment for the heat treated polyester.
  • the heat treatment restores at least 50% of the ductility of the polyester as measured by conventional methods e.g. elongation to break, impact testing (IZOD).
  • IZOD elongation to break, impact testing
  • the heat treatment restores at least 75 % of the ductility, especially at least 80%.
  • Aged polyester or shaped article in the present context means that it has the mechanical properties equivalent to the polyester or article having been stored for 24 hours or more at 20°C.
  • Non-aged polyester or shaped article in the present context means that it has the mechanical properties equivalent to the polyester or shaped article having been freshly processed, i.e. mechanical properties equivalent to storage for up to 24 hours at 20°C, preferably storage for up to and including 1 hour at
  • a polyester composition comprising polyhydroxybutyrate (PHB) or copolymer of hydroxybutyrate units and hydroxyvalerate (PHBV) units and at least one plasticiser thereof, in which ageing has occurred, characterised in that (i) the polyester is restored to its original non-aged properties by a heat treatment, and (ii) subsequent ageing of the polyester is retarded as indicated by substantial improvement of at least one measurement indicative of ageing compared to non heat treated polyester of the same age. Alternately the retardation of subsequent ageing may be indicated by substantial improvement of at least one measurement indicative of ageing compared to heat treated polyester of the same age without plasticiser.
  • PHB polyhydroxybutyrate
  • PHBV hydroxyvalerate
  • the PHA is especially capable of a relatively high level of crystallinity, for example over 30%, especially 50-90%, in the absence of plasticiser.
  • it is or includes at least one microbiologically produced polyester having units of formula I:
  • the molecular weight of the PHA is preferably over 50000, especially over 100000, up to eg 2 x 10 6 .
  • the PHA is conveniently a blend of two or more copolymers differing in the value of m.
  • each such PHA there are side chains as above mentioned.
  • m 4 content in the range 4 - 20 mol %.
  • PHA comprising hydroxybutyrate units and hydroxyvalerate units includes PHBV copolymers containing up to 1 mol percent of other oxyalkanoate units whether introduced deliberately or not.
  • the PHA is preferably a fermentation product, especially of a microbiological process in which a microorganism lays down PHA during normal growth or is caused to do so by cultivation in the absence of one or more nutrients necessary for cell multiplication.
  • the microorganism may be wild or mutated or may have had the necessary genetic material introduced into it. Alternatively the necessary genetic material may be harboured by a eukariote, to effect the microbiological process.
  • the PHA can be extracted from the fermentation product cells by means of an organic solvent, or the cellular protein material may be decomposed leaving microscopic granules of polymer.
  • the cellular protein may be partly or wholly allowed to remain with the PHA, but preferably subjected to cell breakage.
  • the polyhydroxyalkanoate is preferably polyhydroxy-butyrate (PHB) or polyhydroxybutyrate-co-valerate (PHBV), which may be 3- hydroxy or 4-hydroxy or a mixture of both.
  • PHB polyhydroxy-butyrate
  • PHBV polyhydroxybutyrate-co-valerate
  • the composition contains microbiologically produced PHA to the extent of over 50% w/w, especially over 80% w/w.
  • the PHB or PHBV can be a product of synthetic chemistry (Bloembergen and Holden, Macromolecules 1 989, 22, p1 656- 1 663. Bloembergen, Holden, Bluhm, Hamer and Marchessault, Macromolecules 1 989, 22, p1 663-1 669).
  • the polyester composition can contain the usual additional polymer processing additives such as particulate or fibrous or platy filler or reinforcer, fibres, nucleating agents (for example boron nitride, talc or ammonium chloride), and pigments.
  • the nucleant is preferably present in 0.1 to 10phr, especially 1 to 5phr.
  • the composition can be in the form of mouldings, extrudates, coatings, films or fibres, including multilayer coatings, films or fibres.
  • the plasticiser is any material capable of plasticising polyester, i.e. capable of improving the ductility of the polyester and especially any material capable of plasticising PHB or PHBV.
  • the ratio of such plasticiser to PHA is in the range up to and including 40 phr w/w which includes most of the likely uses, particularly 1 to 40 phr w/w, and for making effectively rigid but not brittle articles the range 5-20 phr especially 6-1 2 phr w/w is generally suitable.
  • plasticisers examples are:
  • esters of polybasic acids such as phthalates, isophthalates, citrates, fumarates, glutamates, phosphates or phosphites.
  • the esterified radicals may be for example C- - C 12 alkyl, aryl, aralkyl or aralkyl. Particular examples are dioctyl-, dibaptyl- and dirindecyl- phthalates and dialkylalkylene oxide glutamate (Plasthall 7050);
  • esters and part- of polyhydric alcohols especially glycols, polyglycols and glycerol.
  • the acid-derived radical of the ester typically contains 2-10 carbon atoms. Examples are triacetin, diacetin and glycerol dibenzoate;
  • aromatic sulphonamides such as paratoluenesulphonamide
  • plasticisers are esters of polyhydric alcohols, for example glyceryl esters of C, - C . carboxylic acids.
  • the plasticiser should be biodegradable.
  • a particularly preferred plasticiser is a doubly esterified hydroxycarboxylic acid having at least 3 ester groups in its molecule.
  • Doubly esterified means that at least some of the hydroxy groups of the hydroxycarboxylic acid are esterified with a carboxylic acid and at least some of the carboxy groups thereof are esterified with an alcohol or phenol.
  • Preferably at least the hydroxycarboxylic acid from which the ester is derived is aliphatic or cycloaliphatic. Its backbone structure (that is, apart from carboxy groups) preferably contains 2-6 carbon atoms. It contains preferably 2-4 carboxy groups and 1 -3 hydroxy groups; and preferably the number of carboxy groups exceeds the number of hydroxy groups.
  • the groups with which the carboxy groups are esterified contain preferably 1 -7, especially 2-5 carbon atoms. In the ester molecule they can be the same or different. Preferably they are aliphatic. For thermal stability but biodegradability such aliphatic groups preferably have straight chains. If desired, a small portion of these groups are divalent, so as to give an oligomer suitably containing up to 3 repeating units.
  • the groups with which the hydroxy groups are esterified preferably contain 2-7, especially up to 4, carbon atoms, including the carbon atom of the carboxy of such groups. In the ester molecule such groups can be the same or different. Preferably they are aliphatic and, for thermal stability and biodegradability, have straight chains. If desired, a small proportion of these groups are divalent, so as to give an oligomer suitably containing up to 3 repeating units.
  • polyhydroxyalkanoates may act as plasticisers in this system, for example polycapralactone.
  • the invention also provides a process for improving mechanical properties of an aged polyester comprising at least one polyhydroxyalkanoate and at least one plasticiser thereof, which comprises heating at a temperature whereby (i) the polyester is restored to its original non-aged properties, and (ii) subsequent ageing of the polyester is retarded as indicated by substantial improvement of at least one measurement indicative of ageing compared to non heat treated polyester of the same age. Alternately the retardation of subsequent ageing may be indicated by substantial improvement of at least one measurement indicative of ageing compared to heat treated polyester of the same age without plasticiser.
  • the properties of the polyester or article of the present invention can be assessed using the following measurements : stress-strain curve including calculations of elongation to break, Youngs modulus, and tensile strength; impact testing, for example IZOD; and dynamic mechanical thermal analysis (DMTA). These are all standard methods for testing mechanical properties.
  • any one or more of the above-mentioned characterising properties can be used to monitor the progress of the heat treatment.
  • it is often sufficient to test the article by taking a sample from a batch, cooling it to room temperature and subjecting it to manual flexing.
  • it is often possible to fix the heating temperature and then adopt a time that is fully adequate and affords a small margin to cover accidental variations.
  • a further advantage of the present invention is that after treatment the rate of ageing appears to get slower over a period of a few weeks indicating that substantial stability of measurements indicative of ageing occurs faster in the heat treated polyester than the non heat treated polyester.
  • substantial stability occurs at a level significantly above that for the non heat treated polyester, preferably 50%, especially 100% above that for the non heat treated polyester, i.e. the mechanical properties stabilise at a level substantially improved compared to the non heat treated polyester.
  • the invention also extends to shaped articles of the polyester subjected to the above process.
  • the heating temperature is preferably in the range from 80°C to 1 50°C, especially in the range from 100°C to 140°C.
  • the heating time is typically at least 0.5 min after the article has reached the intended temperature. Since times up to a few hours appear to have no detrimental effect, the time can be chosen to suit the characteristics of the processing plant and economic requirements.
  • Heating can be effected in air or oxygen-depleted or inert gas or in yacuo, or in water or a fluid which does not interfere with the integrity of the polyester, or in a mould.
  • Heat transfer can be by conduction, radiation, convection or resistive heating. Heat transfer methods may include ovens, water baths and hot rollers. A preferred form of heat transfer is by infra red radiation, for example, black body and quartz tubes. The shaped article is generally subjected to infra red radiation for 30 seconds to 1 5 minutes, preferably 30 seconds to 10 minutes.
  • the shaped articles may be run through the oven or other heating method on a continuous belt at a speed which is optimal to enable the shaped article to reach the correct temperature.
  • a preferred method is to
  • the shaped article has a multi-zone system, preferably a 2 zone heat system in which the first zone gives a rapid rate of heating (i.e. the actual temperature in the zone may higher than that to be achieved by the shaped article) to bring it to the actual temperature required and then in the second zone the shaped article is maintained at the actual temperature to be achieved for the desired time period.
  • the first zone gives a rapid rate of heating (i.e. the actual temperature in the zone may higher than that to be achieved by the shaped article) to bring it to the actual temperature required and then in the second zone the shaped article is maintained at the actual temperature to be achieved for the desired time period.
  • the composition can contain the usual polymer processing additives such as fillers, fibres, nucleants and pigments. It can be in the form of mouldings, extrudates, coatings, films or fibres, including multilayer coatings, films or fibres.
  • the invention provides methods of making the composition by mixing its components. If desired, this may be effected in a solvent, such as a halogenated hydrocarbon or alkylene carbonate. Such a method is convenient for coating or for centrifugal spinning of fibres.
  • a solvent such as a halogenated hydrocarbon or alkylene carbonate.
  • plasticiser is mixed with powdered dry polymer and the mixture is treated in conditions of shear, such as in a plastic mill or extruder.
  • the product is then granulated and used as feed for a shaping operation such as extrusion, injection moulding, injection blow- moulding or compression moulding.
  • the composition is especially useful for making the following shaped articles: films, especially for packaging, fibres, non-woven fabrics, extruded nets, personal hygiene products, bottles and drinking vessels, agricultural and horticultural films and vessels, ostomy bags, coated products (such as paper, paperboard, non-woven fabrics), agricultural and horticultural films and vessels, slow-release devices.
  • films especially for packaging, fibres, non-woven fabrics, extruded nets, personal hygiene products, bottles and drinking vessels, agricultural and horticultural films and vessels, ostomy bags, coated products (such as paper, paperboard, non-woven fabrics), agricultural and horticultural films and vessels, slow-release devices.
  • the polymer composition with suitable additives can be used as an adhesive.
  • compositions were prepared by mixing copolymer (500 g) with 1 phr boron nitride acid (if required) plasticiser, and extruding the mixture in a Betol 2520 extruder in these conditions: Zone 1 130°C
  • Screw Speed 100 rpm The extrudate, a single 4mm lace, was crystallised at 50-60°C in a water bath, dried in a current of air and cut into granules.
  • Table 1 A compares the treated polymers with a control sample which was measured for elongation to break prior to administering the heat treatment to the samples.
  • the extension to break of the plasticised homopolymer is higher than that of A or B before the heat treatment. It is not greatly increased by the heat treatment but after only 1 day ageing it can be seen that the extension to break is over 100% better than the untreated control. This trend is maintained over a period of over 6 months as indicated by the 600% and 500% improvements in extension to break compared to the untreated control for the 84 day and 1 99 day periods respectively.
  • compositions each consisting of copolymer 90B 10V, 1 phr of boron nitride and 20 phr of plasticisers were mixed, moulded and tested as described. The bars were aged at room temperature for 56 days, deaged at 1 10°C for 1 h and tested.
  • the plasticisers were D diundecyl phthalate (Jayflex DIUP) (RTM)
  • plasticisers D, E and F the decrease in extension is relatively slower in the period of one week from the heat treatment compared to the non plasticised polymer.
  • the elongation to break values are significantly higher for the plasticised polymer than those for the non plasticised polymer.
  • compositions each consisting of copolymer having 8% HV units, 1 phr of boron nitride and 10 phr of plasticisers were mixed, moulded as
  • the elongation to break (%E) was measured on bottles prepared as described in Example 3.
  • the heat treated bottles were given 4 minutes in an infra red oven with a heater temperature of 250°C. This gave a bottle surface temperature of approximately 1 25 °C-1 30°C.
  • the bottles were aged for several months prior to deaging and testing. Two bottle formulations were tested:
  • Example 5 Dart drop impact performance testing was carried out on bottle walls.
  • the bottles were prepared as described in Example 3, a piece of the bottle wall is cut out and flattened and subjected to the dart drop test which involves dropping an instrumented dart on to the bottle wall held horizontally and measuring the energy absorbed in the impact.
  • the drop conditions were 12% relative humidity, 23.4°C temperature, weight
  • Bottles were also subjected to the bottle drop test as previously described in Example 4. The bottles were aged for 3 weeks prior to heat treatment and then aged for 4 weeks and 8 week at 40°C after heat treatment and were tested 2-3 hours after the heat treatment. The infra red heat treatment gave 3 to 6 minutes in the IR oven providing a temperature at the bottle surface of 130 to 135°C.
  • the bottles were aged for at least one weak prior to heat treatment.
  • the bottle size was 300ml and the bottles were heat treated in an air oven pre-heated to 130°C.
  • the temperature dropped to 108°C whilst treating the bottles and the oven took 20 minutes to re-equilibrate at 130°C.
  • the bottles were held at 120 to 130°C for 20 minutes (or 30 minutes at 1 20°C).
  • the bottles were drop tested from 1 22cm (48 inches) and 1 62cm (60 inches) at 1 week and 1 month after heat treatment. The percentage of bottles surviving the drop test results are given in Table 7. Table 7

Abstract

L'invention concerne un procédé d'amélioration des propriétés mécaniques d'une composition de polyester vieilli comprenant au moins un polyhydroxyalcanoate (PHA) et au moins un plastifiant de celui-ci, ce procédé consistant à chauffer à une température à laquelle (i) on redonne au polyester ses propriétés d'origine non vieillies et (ii) on retarde le vieillissement ultérieur du polyester telle que l'indique une amélioration importante d'au moins une mesure indicatrice du vieillissement comparativement à un polyester du même âge non traité à chaud. L'invention comprend une composition de polyester, et des articles façonnés qui ont été soumis à ce processus, et dont on retarde le vieillissement.
EP94917075A 1993-06-02 1994-06-01 Traitement de polyesters Ceased EP0701581A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB939311401A GB9311401D0 (en) 1993-06-02 1993-06-02 Polyester composition
GB9311401 1993-06-02
PCT/GB1994/001182 WO1994028048A1 (fr) 1993-06-02 1994-06-01 Traitement de polyesters

Publications (1)

Publication Number Publication Date
EP0701581A1 true EP0701581A1 (fr) 1996-03-20

Family

ID=10736523

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94917075A Ceased EP0701581A1 (fr) 1993-06-02 1994-06-01 Traitement de polyesters

Country Status (6)

Country Link
EP (1) EP0701581A1 (fr)
JP (1) JPH09504808A (fr)
AU (1) AU6851494A (fr)
CA (1) CA2163443A1 (fr)
GB (1) GB9311401D0 (fr)
WO (1) WO1994028048A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2284601A (en) * 1999-12-30 2001-07-16 Procter & Gamble Company, The Biodegradable plastic food service items

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8415199D0 (en) * 1984-06-14 1984-07-18 Ici Plc Powders
JPS6169431A (ja) * 1984-09-14 1986-04-10 Teijin Ltd ポリ（β−ヒドロキシ酪酸）成形物の延伸方法
US5076983A (en) * 1990-07-16 1991-12-31 E. I. Du Pont De Nemours And Company Polyhydroxy acid films

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9428048A1 *

Also Published As

Publication number Publication date
JPH09504808A (ja) 1997-05-13
WO1994028048A1 (fr) 1994-12-08
GB9311401D0 (en) 1993-07-21
CA2163443A1 (fr) 1994-12-08
AU6851494A (en) 1994-12-20

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