EP0701582A1 - Traitement de polyesters - Google Patents

Traitement de polyesters

Info

Publication number
EP0701582A1
EP0701582A1 EP94917076A EP94917076A EP0701582A1 EP 0701582 A1 EP0701582 A1 EP 0701582A1 EP 94917076 A EP94917076 A EP 94917076A EP 94917076 A EP94917076 A EP 94917076A EP 0701582 A1 EP0701582 A1 EP 0701582A1
Authority
EP
European Patent Office
Prior art keywords
polyester
units
ageing
aged
heat treated
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
EP94917076A
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 EP0701582A1 publication Critical patent/EP0701582A1/fr
Ceased legal-status Critical Current

Links

Classifications

    • 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
    • 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
    • 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 polyester and shaped polyester articles in particular to polyester and such articles restored to their original non- aged properties after ageing has taken place and a process of de-ageing such polyester and articles.
  • polyester poly[(R)-3-hydroxybutyrate] (PHB) and copolymers of _(R)-3-hydroxybutyrate] with [(R)-3-hydroxyvalerate] (PHBV) when freshly moulded show ductile behaviour, subsequent ageing seriously embrittles such polymers and copolymers and hampers their applicability.
  • PHB polyester poly[(R)-3-hydroxybutyrate]
  • PHBV poly(R)-3-hydroxyvalerate]
  • a polyester composition consisting essentially of copolymer of hydroxybutyrate units and hydroxyvalerate units 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.
  • a shaped article at least partly made of a polyester composition consisting essentially of copolymer of hydroxy butyrate units and hydroxyvalerate units 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.
  • At least partly made means having structural components made of PHBV to such an extent that ageing of the PHBV component ages the whole article.
  • PHBV may be homogeneously mixed with other biodegradable polymers such as polylactides.
  • the minimum amount of PHBV is at least 30% w /w.
  • articles having PHBV 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 PHBV inclusions, are within the invention.
  • the minimum amount of PHBV is at least 30% w /w.
  • PHBV consisting essentially of hydroxybutyrate units and hydroxyvalerate units includes PHBV copolymers containing up to 1 mol percent of other oxyalkanoate units whether introduced deliberately or not.
  • Substantial improvement means that the measurement indicative of ageing, for example, elongation to break, is improved by 50% or more, preferably 70% or more, compared to the non-heat treated aged polyester at the same age as the heat treated aged polyester.
  • 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 original non- aged 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 80% or more.
  • 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 20°C of having been processed.
  • the PHBV is capable of a relatively high level of crystallinity, for example over 30%, especially 50-90%, in the absence of plasticiser. It consists of repetitive units of formula I: - O - C m H n - CO - I where m is 3 or 4 and n is 2m or 2m-2. Typically C m H n contains 2 carbon atoms in the polymer chain and a C- or C 2 side chain on the carbon next to oxygen in the chain.
  • Mw of the PHBV is for example from 50000 to 2 x 10 6 , especially over
  • the copolymer may be a blend of two or more copolymers differing in the value of m.
  • a particular example contains
  • the PHBV can be a product of fermentation, especially of a microbiological process in which a microorganism lays down PHBV during growth or is caused to do so by cultivation in starvation of one or more nutrients necessary for cell multiplication.
  • the microorganisms may be wild or mutated or may have the necessary genetic material introduced into it. Alternatively the necessary genetic material may be harboured by an eukaryote, to effect the microbiological process.
  • An example of a suitable microbiological process is described in
  • the PHBV 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 PHBV.
  • the polyhydroxybutyrate-co-valerate may be 3-hydroxy or 4-hydroxy or a mixture of both. Especially preferred is the (R)-3-hydroxy form of PHBV. Alternately, the PHBV can be a product of synthetic chemistry
  • the composition contains microbiologically produced PHBV to the extent of over 50% w/w, especially 80% w/w.
  • the polyester composition can contain small amounts of the usual polymer processing additives such as particulate or fibrous or platy filler or reinforcer, fibres nucleating agents and pigments.
  • the nucleant is preferably present in 0.1 to 10 phr, especially 1 to 5 phr, and may be for example, boron nitride, talc or ammonium chloride.
  • the present invention does not include plasticisers as part of the polyester composition.
  • 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.
  • the invention also provides a process for improving mechanical properties of an aged polyester comprising copolymer of hydroxybutyrate units and hydroxyvalerate units which comprises heating the polyester 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.
  • the invention also extends to shaped articles of the polyester subjected to the above process.
  • 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 polyester or 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 often occurs faster in the heat treated polyester than the non heat treated polyester.
  • substantial stability of such measurements occurs at a level significantly 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 mechanical properties stabilise at a level at least 50% improved compared to the same measurements taken on the non heat treated polyester of the same age.
  • the heating temperature i.e. the temperature to which the shaped article is heated, is preferably in the range from 80°C to 1 50°C, especially in the range from 100°C to 140°C.
  • the temperature may be measured on the surface of the shaped article.
  • the heating time is typically at least a few seconds, preferably from 5 seconds to 20 hours, especially 0.5 min to 14 hours, particularly 0.5 min to 2 hours, after the article has reached the intended temperature.
  • the heating time required for optimal effect is dependent on the heating temperature, i.e. the higher the temperature the less time that is required to achieve optimal effect. Also the temperature can be chosen to suit the characteristics of the copolymer of PHBV, the processing plant and economic requirements.
  • Heating can be effected in air or oxygen-depleted or inert gas or ]n vacuo, 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 1 0 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 have 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.
  • Processes for preparing shaped articles include for example, extrusion, production of film, coatings, injection moulding, thermoforming, fibre spinning and blow moulding.
  • the invention provides processes of shaping the polymer composition and the resulting shaped articles.
  • Articles include fibres, films especially for packaging, coated products (such as paper, board, non-woven fabrics), fibres, non- woven fabrics, extruded nets, personal hygiene products, bottles and drinking vessels, agricultural and horticultural films and vessels, containers, disposable items such as ostomy bags, incontinence devices and wound care products, sustained release systems for drugs and agrochemicals and adhesives.
  • Mw/Mn 3.1 2 was mixed with 1 .0% of boron nitride nucleating agent in a Hobart (RTM) mixer for about 1 0 min.
  • the mixture was fed to a Betol 2520 (RTM) 25 mm screw extruder operated at maximum temperature of 1 50°C with a screw speed of 100 rpm.
  • the 4 mm strand so produced was crystallised at 60°C in a water bath and granulated.
  • the granules were injection-moulded into dumbbell-shaped specimens according to ISO R 537/2, their prismatic part measuring 40 x 5 x 1 2 mm using a Boy 1 5S (RTM) machine at a maximum barrel temperature 1 50°C, injection time 1 0 sec, screw speed 220 rpm, injection pressure 5MPa, mould temperature 60°C, cooling time 30 sec.
  • the specimens were allowed to age for at least 2 days at ambient temperature. Then the specimens were subjected to the following treatments :
  • the four specimens were examined for stress-strain behaviour using an Instron (RTM) 1 1 22 tensile testing machine fitted with a Nene data analysis system. A clamp separation of 50 mm and a crosshead speed of 20 mm. min '1 were used. Each sample consisted of 5 bars and an average value taken.
  • RTM Instron
  • the untreated PHBV bars rapidly lost ductility and within one day elongation to break had been reduced to 10% of the original value of the untreated PHBV bars tested immediately after preparation.
  • the PHBV bars treated at 100 °C were 50% more ductile than the untreated.
  • 140°C were approximately 5 times (400%) more ductile than the corresponding untreated PHBV bars. At one week after treatment the treated PHBV bars were 100%, 200% and 600% respectively more ductile than the untreated PHBV bars. At one month after treatment the treated PHBV bars were 150 to 200% more ductile than the untreated
  • the untreated PHBV bars rapidly lost ductility and within one day elongation to break had been reduced to 1 8% of the original value of the untreated PHBV bars tested immediately after preparation.
  • the PHBV bars treated at 100°C were 100% more ductile than the untreated bars at the same age.
  • the PHBV bars treated at 140°C were approximately 4 times (300%) more ductile than the corresponding untreated PHBV bars.
  • the treated PHBV bars were approximately 100% and 200% respectively more ductile than the untreated PHBV bars.
  • At one month after treatment the treated PHBV bars were 50% and 1 20% respectively more ductile than the untreated PHBV.
  • Injection moulded impact bars were prepared as described in Example 1 , with the nozzle at 1 50°C, barrel zone 1 at 1 30°C, barrel zone 2 at 140°, injection time being 1 5 seconds, and the cooling time being 1 5 seconds. The bars were notched at 1 mm radius.
  • IZOD impact strength was determined using a Zwick pendulum apparatus.
  • the heat treated bars were considerably more resistant to impact than the untreated bars.
  • the impact results show a slowing down in the deterioration of the impact resistance for the treated bars and consequently at 28 days after treatment the treated bars are more than twice as resistant to impact than the untreated bars.
  • the impact resistance of the untreated bars continues to deteriorate significantly over time.
  • Example 4 Bottle impact performance test.
  • Bottles were made from a formulation of PHBV containing 8% HV units, and 1 phr boron nitride by extrusion blow moulding with a Battenfield Fischer (35mm).
  • the bottles contained 380ml (1 2 fl oz).
  • the bottles were aged for 1 week before carrying out this test.
  • a number of bottles were subjected to infra red heating for various times to give a bottle surface temperature between 1 25 and 130°C.
  • the treated and untreated bottles were filled with water and conditioned for 24 hours at 22°C.
  • the bottles were dropped from 48 inches (122cm) onto a 1 .3cm (V inch) steel plate angled at 5°.
  • Table 4 Percentage of bottles surviving drop
  • Bottle drop survival was significantly improved by the heat treatment compared to the non heat treated bottles.

Abstract

L'invention concerne un procédé d'amélioration d'une composition de polyester vieilli se composant essentiellement du copolymère des unités d'hydroxybutyrate et des unités d'hydroxyvalérate, et qui consiste à chauffer le polyester à une température à laquelle (i) on redonne au polyester ses propriétés d'origine non vieillies, et (ii) à laquelle on retarde le vieilissement du polyester, tel que l'indique une amélioration importante d'au moins une mesure indicatrice du vieilissement comparativement à un polyester du même age non traité à chaud. L'invention comprend la composition de polyester, et les articles façonnés qui ont été soumis à ce procédé, et dont on retarde le vieillissement.
EP94917076A 1993-06-02 1994-06-01 Traitement de polyesters Ceased EP0701582A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB939311400A GB9311400D0 (en) 1993-06-02 1993-06-02 Polyester
GB9311400 1993-06-02
PCT/GB1994/001183 WO1994028049A1 (fr) 1993-06-02 1994-06-01 Traitement de polyesters

Publications (1)

Publication Number Publication Date
EP0701582A1 true EP0701582A1 (fr) 1996-03-20

Family

ID=10736522

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94917076A Ceased EP0701582A1 (fr) 1993-06-02 1994-06-01 Traitement de polyesters

Country Status (6)

Country Link
EP (1) EP0701582A1 (fr)
JP (1) JPH09501449A (fr)
AU (1) AU6851594A (fr)
CA (1) CA2163553A1 (fr)
GB (1) GB9311400D0 (fr)
WO (1) WO1994028049A1 (fr)

Family Cites Families (2)

* 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

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9428049A1 *

Also Published As

Publication number Publication date
WO1994028049A1 (fr) 1994-12-08
GB9311400D0 (en) 1993-07-21
AU6851594A (en) 1994-12-20
CA2163553A1 (fr) 1994-12-08
JPH09501449A (ja) 1997-02-10

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