Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • 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
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/022—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the choice of material
• • 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
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
  • B29C48/395—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders
  • B29C48/40—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders using two or more parallel screws or at least two parallel non-intermeshing screws, e.g. twin screw extruders
• • 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
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
  • B29C48/50—Details of extruders
  • B29C48/505—Screws
  • B29C48/55—Screws having reverse-feeding elements
• • 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
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
  • B29C48/50—Details of extruders
  • B29C48/505—Screws
  • B29C48/57—Screws provided with kneading disc-like elements, e.g. with oval-shaped elements
• • 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
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
  • B29C48/50—Details of extruders
  • B29C48/505—Screws
  • B29C48/625—Screws characterised by the ratio of the threaded length of the screw to its outside diameter [L/D ratio]
• • 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
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
  • B29C48/50—Details of extruders
  • B29C48/505—Screws
  • B29C48/64—Screws with two or more threads
  • B29C48/645—Screws with two or more threads neighbouring threads and channels having identical configurations
• • 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
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/78—Thermal treatment of the extrusion moulding material or of preformed parts or layers, e.g. by heating or cooling
  • B29C48/80—Thermal treatment of the extrusion moulding material or of preformed parts or layers, e.g. by heating or cooling at the plasticising zone, e.g. by heating cylinders
  • B29C48/83—Heating or cooling the cylinders
  • B29C48/832—Heating
• • 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
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/92—Measuring, controlling or regulating
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/18—Plasticising macromolecular compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L101/00—Compositions of unspecified macromolecular compounds
  • C08L101/16—Compositions of unspecified macromolecular compounds the macromolecular compounds being biodegradable
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
  • C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L99/00—Compositions of natural macromolecular compounds or of derivatives thereof not provided for in groups C08L89/00 - C08L97/00
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2300/00—Characterised by the use of unspecified polymers
  • C08J2300/16—Biodegradable polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2399/00—Characterised by the use of natural macromolecular compounds or of derivatives thereof not provided for in groups C08J2301/00 - C08J2307/00 or C08J2389/00 - C08J2397/00
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2201/00—Properties
  • C08L2201/06—Biodegradable

Definitions

• the present invention relates to a method of manufacturing a biodegradable material made from polymers and flours, preferably cereals.
• biodegradable materials are intended to replace synthetic polymeric materials traditionally used in applications such as packaging, the manufacture of films, injected parts and other objects.
• biodegradable in the context of the present invention any biological, physical and / or chemical degradation, at the molecular level, of the substances by the action of environmental factors (in particular enzymes resulting from the processes of metabolism of microorganisms) .
• environmental factors in particular enzymes resulting from the processes of metabolism of microorganisms
• biodegradation can be defined as the decomposition of organic matter into carbon dioxide, water, biomass and / or methane by micro-organisms (bacteria, enzymes, fungi).
• the biodegradability shall be determined for each packaging material or each significant organic constituent of the packaging material, meaning any organic constituent representing more than 1% of the dry mass of this material
• each material under test must be inherently and ultimately biodegradable as demonstrated by laboratory tests (identical to NSO 14851: 1999 and 14852: 1999) and must meet the criteria and at the following acceptance levels: in an aerobic environment, the percentage of biodegradation of the test material shall be 90% in total at least 90% of the maximum degradation of an appropriate reference substance plateau has been achieved both for the test material and for the reference substance (eg cellulose). The duration of the test must be at most 6 months. In anaerobic environment, the test period must be a maximum of 2 months and the biodegradation percentage based on biogas production must be greater than or equal to 50% of the theoretical value applicable to the test material.
• each material under test must decay during a biological waste treatment process: after a composting process not exceeding 12 weeks, not more than 10% of the initial dry mass of the test material sieving may be refused for a 2 mm mesh vacuum.
• the final compost must meet the European requirements or, failing that, the national requirements relating to the quality of the compost.
• a biodegradable material is understood as a decomposing material according to the definition given above.
• biodegradable materials based on mixtures between a synthetic polymer and an isolated natural polymer such as starch, cellulose, hemicellulose, fiber, hemp fiber, or other is known.
• US Patents 5,095,054 and EP 327,505 disclose materials made from a synthetic polymer and a destructured starch.
• the starch is previously destructured at temperatures of 130 ° C. to 190 ° C. under 5 ⁇ 10 5 N / m 2 .
• the starch may also be treated with agents such as urea, alkali or alkaline earth hydroxides as described in European Patents EP 400 531 and EP 494 287, or may be subjected to prior chemical treatment to modify its state. surface and make its surface hydrophobic.
• DE 102 30 776 discloses the extrusion of a plasticized cereal flour with a mixture of sorbitol and glycerol with a polyester (paragraph [0016], and especially Example 1). The examples mention the use of a twin-screw extruder, but do not specify its nature.
• US 2006/0043629 discloses compositions obtained by mixing a soy flour with glycerol, subsequently mixed with a biodegradable polymer (see especially paragraphs [0093] and [0096]).
• the flour used is not a cereal flour, and thus has strong differences in composition with the flours used in the context of the present invention: the soya flour is richer in lipids and proteins than the cereal flour, which presents a complex composition of carbohydrates.
• FR 2,856,405 was filed by the Applicant and is discussed in this application, through the teaching of WO 2004/1 13433, application of the same family.
• the teaching of WO 2004/113433 serves as a basis for the comparative examples.
• DE 198 02 718 (D4) describes the mixture of corn flour with glycerol and a biodegradable polyester. This mixing is carried out at one time, which defines a difference with the object of the process as envisaged, which envisages a plastification of the flour before adding the polymeric agent.
• the present invention uses flour, preferably cereal flour as raw material, in place of isolated starch.
• This flour actually contains starch, but also other compounds that can influence the quality of the materials obtained, such as proteins, lipids and other sugars less complex than starch. Thus, it is likely that the presence of these other compounds affects the mixing capacity of the flour and the synthetic polymer.
• biodegradable materials from flour is also known in the art, as described in particular in the application WO 00/14154, which specifies certain conditions for incorporating cereal flour into a polymer matrix.
• This application mentions in particular that the cereal flours do not undergo any treatment such as, for example, gelatinization or destructuration or modification of the surface of the starches, and that no plasticizers such as urea or glycerol are used.
• the application WO 2004/1 13433 also relates to mixtures of cereal fillers and biodegradable polymer.
• the cereal feed corresponds to flour that has been transformed using a plasticizer to modify its rheological and thermal properties, so that they are similar to those of the biodegradable polymer (obtaining thermoplastic flour).
• This request thus specifies the conditions for mixing the flour and the plasticizer.
• Figure 6 of this application shows an example configuration of Screw a twin-screw extruder to prepare a ThermoPlastic Flour (FTP).
• FTP ThermoPlastic Flour
• the present invention thus relates to a method for producing a biodegradable material from flour and at least one biodegradable polymer, comprising the step of
• step a) being carried out in a twin-screw extruder, each screw having the same diameter D, characterized in that said step a) of incorporation of the plasticizer into the flour is carried out over a length of at least 6 times the diameter of the screw (6 x D). Preferably, this incorporation is carried out over a continuous length, that is to say without there being a relaxation phase of the mixture during incorporation.
• the biodegradable material thus obtained may be called "compound” and is intended to be reworked in the presence or absence of other polymers to obtain biodegradable products, as described in WO 2004/113433 or in WO 2008/003671. it is generally in the form of granules.
• this biodegradable material can be mixed with a biodegradable polymer in a single-screw extruder, for extrusion-inflation processing.
• Inflation extrusion is a known continuous process in which the granules (compound) enter a heated tube with a worm. These granules can be of one type or of several types when it is desired to carry out a mixture.
• the homogenized material is pushed, compressed and then passes through a die.
• the polymer thus formed is then dilated with the compressed air at the extruder / die exit.
• the outlet of the extruder is vertical, and compressed air is blown into the melt which swells and rises vertically into a long film bubble.
• rollers flatten the film into a planar sheath which is cooled and wound on reels.
• This method is well known for obtaining films used in the manufacture of packaging, garbage bags, freezer bags, medical bags for infusion and soft and thin sheets of horticultural greenhouses.
• the film is obtained by extrusion of flat film (or cast film).
• the polymer falls on a temperature-controlled chill roll at the die outlet. The cold allows recrystallization, and the rotation speed of the rollers allows the adjustment of the thickness.
• Twin-screw extrusion is a process known to those skilled in the art.
• the extrusion machine is more particularly of co-rotating two-screw co-penetrating type, and comprises two screws driven length L and diameter D, rotating about their axes by a motor and a reducer, inside. an elongate envelope forming a sheath, surrounded by heating elements.
• These screws are provided with helical threads, modular screw elements, which mesh with each other, characterized by their ratio outer diameter (of) on internal diameter (di) determining the free volume of the screw.
• the inner wall of the sheath forms two intersecting lobes of diameter slightly greater than the outer diameter of the net.
• the ratios (of / di) and (L / D) are two important features of the extrusion machine. Whatever the diameter chosen, the ratio of the screw length to the diameter is preferably greater than 28, and preferably of the order of 40.
• the set of elements is called configuration, and is characteristic of the objective to be achieved.
• transport elements of the material and elements that make it possible to provide mechanical energy (shearing of the material).
• the material advances into the extruder being pushed by the material introduced at the inlet of the extruder, the flow rate being constant.
• the heating elements make it possible to maintain a temperature of between 30 and 190 ° C.
• the extrusion machine comprises continuously, from upstream to downstream in the transfer direction of the material, a plurality of treatment zones, consisting inter alia of:
• a zone Z2 for introducing the biodegradable polymer or polymers
• a zone Z3 for mixing the transformed flour and the biodegradable polymer (s)
• Step a) of the process described in the present application is thus carried out in zone Z1, which represents, in a preferred embodiment, at least 35% of the total length L of the extrusion machine.
• This zone Z1 comprises an area of introduction of the cereal material (flour) and of the plasticizer, a zone of transport and temperature rise of these two elements, and a mixing zone of these elements, which corresponds to the implementation of step a) of the claimed process.
• the total L / D ratio is equal to 40, and the length of the Z1 zone is greater than 16 times D (16D) (for example equal to 18.5 times D (18.5 D)). ).
• the modules 1 to 4 of FIG. 6 of WO 2004/113433 correspond to the zone Z1 thus defined.
• no addition of biodegradable polymer is carried out in the extruder described in Figure 6 (which is read in the light of Figure 7) of WO 2004/1 13433.
• the mixture between the flour and the plasticizer is carried out in module 4.
• the abbreviations used in this figure correspond to the modular elements carried on the two screws of the extruder: C2F: conjugate with double thread (conveying), MAL2 (bilobal mixers), BL02 (monolobe eccentric on each screw: shear).
• relaxation ranges transport materialized by the double-threads
• the incorporation of the plasticizer in the cereal material is achieved by the use of modular elements having a profile for shearing the cereal flour / plasticizer mixture.
• modular elements will thus lead to a local decrease in the available volume (thus increasing the internal pressure, converted into thermal energy) and an increase in the stress per unit area.
• the modular elements present on the screws also transform the linear flow for transport / conveying due to the modular elements in double-threads in a radial flow.
• modular elements carrying monolobe kneaders (FIG. 1), or to set up, in the flour processing zone, various modular elements, some of them being monolobes and other bilobes.
• a filling ratio of between 25% and 75% is sought in this zone for processing the flour with the plasticizer.
• the mechanical energy provided by the mixing elements can not be transmitted to the materials if the filling rate is too low, and mixing is not performed for a filling rate too high.
• the cereal flours that can be used in the context of the present invention are described in WO 2004/1 13433 or WO 00/14154.
• T55 wheat flour, whole wheat, corn or any other grain may be used.
• Cereal flour can also be modified by various techniques, in particular drying, which makes it possible to reduce the humidity or the turboseparation which makes it possible to separate a cereal material into two granulometrically different fractions: a richer in starch (large particles) and a richer in protein (small particles).
• the plasticizers used in the present process are molecules of low molecular weight, natural or synthetic, making it possible to lower the melting temperature of a polymer.
• water it is possible to use water (it is therefore not working at reduced humidity levels), or another plasticizing agent chosen from the group consisting of glycerol and its derivatives such as di- or polyglycerol, from castor oil, linseed oil, rapeseed oil, sunflower oil, corn oil, polyols, sorbitol and its derivatives, ethers and esters of polyols, urea, sodium chloride, alkali or alkaline earth metal halides or hydroxides, and mixtures thereof.
• a person skilled in the art can use any other known plasticizer which makes it possible to offer the cereal material with which it is associated a rheological behavior identical to or at least very close to that of the polymer of the biodegradable material.
• Plant-based plasticisers are preferably used.
• glycerol, water, or a mixture of glycerol and water is used.
• a process for obtaining a biodegradable material from cereal flour and a biodegradable polymer, comprising the transformation of the flour by the effect of a plasticizer composed of a mixture of glycerol and water (prior to mixing with the biodegradable polymer) is also an object of the invention.
• the ratio glycerol: water is between 1, 5: 1 and 1 1: 1 (weight for weight), and is preferably between 3: 1 and 5: 1.
• a ratio glycerol: water equal to 1 (between 0.9 and 1, 1), or between 0.66 and 1, 2.
• plasticizer therefore covers the use of a single compound, or a mixture of several compounds.
• the process according to the invention also preferably comprises a step b) of mixing said transformed flour obtained with said biodegradable polymer (s). This step is carried out downstream of zone Z1 in the twin-screw extruder.
• the biodegradable polymer used in the context of the present process may be a plant material such as wood flour as described in European Patent EP 652 910. It may also be chosen from polyols as described in European Patent EP 575 349, or copolymers of ⁇ -caprolactone and isocyanates as described in European Patent EP 539 541.
• biodegradable polymers are used in the process according to the invention.
• the biodegradable polymer according to the present invention may be of fossil origin, that is to say a plastic material and, in particular a thermoplastic material. It can be chosen from the group consisting of aliphatic polyesters, aromatic aliphatic polyesters, aliphatic-aromatic copolyesters and in particular butanediol-adipic and terephthalic acid copolyesters, polyamides, polyesteramides, polyethers. , polyesters - ethers - amides, polyesters - urethanes, polyester - ureas and mixtures thereof.
• Aromatic aliphatic copolyesters are preferably used as described in EP 819 147 in the context of the present invention.
• polybutylene adipate terephthalate (PBAT) is particularly suitable.
• a biodegradable polymer of microbial or vegetable origin is used, rather than a polymer of fossil origin. It is then in particular chosen from the group consisting of polylactic acid (PLA) or microbial polymers such as polyalcanoates of polybutyrate type (PHB), polyvalérate (PHV), or polybutyrate valérate (PHBV). It is also possible to use a polymer of the family of lactones and polycaprolactones, or a mixture of polymers of microbial origin and of fossil origin.
• PLA polylactic acid
• PHB polyvalérate
• PHBV polybutyrate valérate
• biodegradable polymers are used, and in particular the mixture of a biodegradable polymer of fossil origin and a biodegradable polymer of vegetable origin.
• a mixture of polybutylene adipate co-terephthalate (PBAT) and polylactic acid (PLA) is preferably used.
• PBAT polybutylene adipate co-terephthalate
• PLA polylactic acid
• Ecoflex® is also developed by BASF, and is an aliphatic -aromatic copolyester
• additives may also be incorporated into the manufactured materials.
• additives can be mineral fillers, vegetable fillers, pigments, blocking agents, UV absorbers, stabilizers
• UV, carbon black, release agents or any other acceptable additive UV, carbon black, release agents or any other acceptable additive.
• the cereal flours that can be used in the present process are described in particular in the application WO 2004/1 13433. It is thus possible to use maize, wheat, barley, soy, rice or any other cereal flours.
• the flour used in the process according to the invention usually contains between 65 and 99% starch, 2 and 20% protein, 0.8 and 15% fat and 2 and 15% water. It should be noted that other types of flours containing starch and other polymers such as potato flours could be used.
• a quantity of flour is preferably used such that the biodegradable material obtained contains between 15 and 80% (by mass) of flour, preferably between 15 and 60%, more preferably between 20 and 50% by weight. %. Depending on the objective, more or less flour is used. If the material is an intermediate material, which must subsequently be mixed with other polymers to form the biodegradable objects (films, molded or blown objects, etc.), it then advantageously contains between 30 and 70% of flour. If the material is directly usable for the production of biodegradable objects, then it usually contains between 15 and 60% flour.
• a quantity of biodegradable polymer (alone or in a mixture) is preferably used such that the biodegradable material obtained contains between 10 and 85% (by weight) of biodegradable polymer (s), preferably between 30 and 80%.
• composition of a material obtained by the implementation of the process comprises between 15 and 80% of cereal flour, between 10 and 85% of biodegradable polymer (s) of fossil origin and / or of plant origin, between 2 and 40% of plasticizer.
• this material comprises:
• biodegradable polymer of fossil origin and / or vegetable origin selected from aliphatic-aromatic copolyesters, polylactic acids, microbial polymers, and mixtures thereof
• a plasticizer preferably about 10 to 20%, between 0 and 5% of urea
• Such a material is also an object of the present invention. It thus relates to a biodegradable material comprising a cereal flour transformed by adding a plasticizer, and at least one biodegradable polymer, characterized in that the reduced specific viscosity of the amylaceous phase of said material (at a concentration of 3 mg / ml), measured by capillary viscometry, is between 15 and 85 ml / g, preferably between 40 and 85 ml / g.
• the intrinsic viscosity of starch samples may vary depending on its origin as shown by Narpinder Singh et al. in Structural, thermal and viscoelastic cheracteristics of starches separated from normal, sugary and waxy maize, Food Hydrocolloids 20 (2006) 923-935).
• the invention thus also relates to a biodegradable material comprising a cereal flour transformed by adding a plasticizer, and at least one biodegradable polymer, characterized in that the specific viscosity relative reduction of the starch phase of said material (at a concentration of 3 mg / ml), measured by capillary viscometry is between 0.10 and 0.65, preferably between 0.35 and 0.60.
• the viscosity of the material is indeed representative of the level of transformation of the cereal flour after contacting with the plasticizer.
• starch is a natural polymer, in the form of granules of 1 to 100 microns, the size and shape of which vary according to their botanical origin. It is composed of two polysaccharide fractions: amylose (usually 20-30%) and amylopectin (70-80%).
• Amylose linear polymer
• Amylopectin is a branched polymer. It is composed of short chains of glucose units linked by ⁇ -1, 4 bonds in the linear part and ⁇ -1, 6 bonds at the branching points.
• the starch contained in the cereal flours is in the form of granules.
• the cereal flour is subjected to a high temperature treatment in the presence of a plasticizer. This transformation is carried out by means of an extruder (usually twin-screw) by subjecting the system to mechanical and thermal energy.
• extruder usually twin-screw
• the level of processing of cereal flour can be defined by:
• amylose-lipid complexes which crystallize (type V or E type X-ray diffractograms according to the size of the complexing agent);
• Solution viscometry is an analytical technique that makes it possible to evaluate the level of depolymerization of a starch subjected to a thermomechanical treatment (for example of twin-screw extrusion type). At zero concentration, the intrinsic viscosity is a measure of the molar mass of a polymer since:
• [ ⁇ ] corresponds to the extrapolation for a zero concentration of the curve representing the reduced specific viscosity as a function of the concentration.
• the reduced specific viscosity corresponds to the specific viscosity brought to concentration (see also below ⁇ S p / c) -
• Capillary viscometry is a simple analytical technique that provides access to the molecular weight of a polymer by determining the viscosity index.
• the variation at a given concentration of the reduced specific viscosity of a dilute solution is quasi-linear as a function of the molecular weight of the polymer (and is therefore related to the level of depolymerization of the starch). It was chosen to follow the reduced specific viscosity and to calculate the relative reduced specific viscosity of a cereal flour solution at a given concentration of 3 mg / ml.
• the measurement of the relative reduced specific viscosity of the starch is indeed an element of characterization of the average molar mass of the starch which has undergone the mechanical and thermal treatment with the plasticizer, and therefore of its level of transformation (depolymerization ). Since the structure of the biodegradable material according to the invention is related to the level of transformation of the starch, the measurement of the viscosity is therefore a relevant parameter of characterization of this material. As seen above, this viscosity measurement is known in the art and routinely used by those skilled in the art.
• the claimed biodegradable materials consist of a flour / plasticizer / biodegradable polymer (s) mixture
• the level of flour transformation (starch depolymerization) is evaluated. 1- Extraction of about 60 mg of the cereal flour, and drying (extraction carried out on film samples). The starch phase is the result of the extraction of cereal flour.
• the protocol for measuring the reduced specific viscosity is as follows:
• the biodegradable materials according to the invention consist of a mixture cereal flour / plasticizer / polymer (s) biodegradable (s).
• s mixture cereal flour / plasticizer / polymer
• s biodegradable
• Extraction is performed on film samples produced from the claimed biodegradable materials. This step makes it possible to remove the biodegradable polymer, and to keep only the amylaceous phase.
• the film samples are produced on the same extrusion line. identical processes (same temperature profile, same crystallization height, same inflation rate, etc.). The results do not depend on the nature of the starting film. Said extraction is carried out by means of a solvent of the polymer (s) constituting the film, which solvent must be a non-solvent of the flour.
• the solubilization of the amylaceous phase extracted from the films obtained from the biodegradable material according to the invention (at a concentration of 3 mg / ml) is carried out in a solution of potassium hydroxide (KOH) at 1 M with stirring for 1 hour at 60 ° C.
• KOH potassium hydroxide
• ⁇ sp / c- to reduced specific viscosity of the flour at a given concentration (C) before thermomechanical treatment (twin-screw extrusion in our case)
• the invention also relates to plastic films comprising a biodegradable material according to the invention.
• these films are prepared by extrusion-inflating a biodegradable material according to the invention, alone or by adding another biodegradable polymer, as described above.
• These films may be single-layer or multi-layer, as described in WO 2008/003671.
• the more advanced level of processing of the starch achieved by the process according to the invention greatly improves the quality of the films that can be produced from the biodegradable material thus obtained, and defined above.
• Haze is the haze of a product caused by the scattering of light transmitted through the product. Indeed, the light can be diffused by particles present within the sample (we can cite for example the pigment particles) or by surface defects.
• optical properties of a plastic film sample can be determined inter alia by measuring the Haze.
• the latter is defined according to the standard
• ASTM D1003 as the amount of light that deflects an average of more than 2.5 ° from the incident light beam. It is expressed as a percentage. A material with a Haze greater than 30% is considered to be diffusing. Haze value is given by:
• the Haze measurement protocol is as follows:
• Figure 1 Table summarizing the effects of screw elements in a co-penetrating and co-rotating twin-screw extruder (source: Ika Amalia KARTIKA's thesis).
• the transformed flour is brought into contact with the biodegradable polymer (s) after a length of 18.5D.
• This profile is similar to the profile described in Figure 6 of WO 2004/1 13433.
• the flour processing zone thus measures 4.75 D and has a relaxation phase.
• the transformed flour is brought into contact with the biodegradable polymer (s) after a length of 18.5D.
• the flour processing zone is therefore 6.5 D and without relaxation phase.
• the films produced are three-layer films with a thickness of 30 .mu.m, 20/60/20 structure.
• the outer and inner layers consist of PBAT, and the core layer of the biodegradable material is obtained after extrusion under the above conditions.
• % AR percent elongation at break
• Ra Average arithmetic mean deviation of roughness profile
• a film is produced as mentioned above.
• the reduced specific viscosity is 99.51 ml / g.
• the screw profile A is used, and the formulation I
• exogenous water with glycerol makes it possible to improve the mechanical properties of the films generated (Young's modulus) as well as their level of cloudiness.
• the reduced specific viscosity is 56.57 ml / g.
• the reduced specific viscosity obtained is 70.73 ml / g.
• the screw profile A is used, and the formulation
• the reduced specific viscosity obtained is 49.78 ml / g.
• the films made are also of better quality (mechanics, as attested by the Young and Optical Module, as attested by the Haze).
• the use of a more shearing screw profile and the optimization of the plasticizer make it possible to improve the properties of the films produced.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Biological Depolymerization Polymers (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)

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  • 2009-07-03 FR FR0903267A patent/FR2947557B1/fr not_active Expired - Fee Related
• 2010
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  • 2010-07-02 US US13/381,821 patent/US20120157581A1/en not_active Abandoned
  • 2010-07-02 WO PCT/FR2010/051404 patent/WO2011001128A1/fr not_active Ceased
  • 2010-07-02 IN IN332DEN2012 patent/IN2012DN00332A/en unknown
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