Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L3/00—Compositions of starch, amylose or amylopectin or of their derivatives or degradation products
  • C08L3/02—Starch; Degradation products thereof, e.g. dextrin
• • 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
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L31/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, of carbonic acid or of a haloformic acid; Compositions of derivatives of such polymers
  • C08L31/02—Homopolymers or copolymers of esters of monocarboxylic acids
  • C08L31/04—Homopolymers or copolymers of vinyl acetate
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
  • C08L33/04—Homopolymers or copolymers of esters
  • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
  • C08L33/08—Homopolymers or copolymers of acrylic acid esters
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
  • C08L33/04—Homopolymers or copolymers of esters
  • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
  • C08L33/10—Homopolymers or copolymers of methacrylic acid esters
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L75/00—Compositions of polyureas or polyurethanes; Compositions of derivatives of such polymers

Definitions

• the invention relates to a shapeable composite material based on a starch which is thermomechanically digested in a manner known per se - hereinafter also referred to as TPS - in a homogeneous mixture with selected synthetic thermoplastic polymer compounds - hereinafter also referred to as SPV.
• TPS thermomechanically digested in a manner known per se - hereinafter also referred to as TPS - in a homogeneous mixture with selected synthetic thermoplastic polymer compounds - hereinafter also referred to as SPV.
• the core of the action according to the invention lies in the selection of certain structural elements of this SPV and their numerical assignment to the starch content in the composite material.
• EP-A2327505 describes polymer blend materials which are obtained from a melt of water-containing destructurized starch and at least one essentially water-insoluble synthetic thermoplastic polymer compound.
• the starch is first converted to TPS with the addition of auxiliaries by treatment in an extruder at elevated temperatures and processed into granules.
• the water content in the granulate is adjusted approximately to the range of the water content of natural starch (approx. 17% by weight).
• These starch granules are then mixed in a predetermined mixing ratio with synthetic polymer compounds in the dry state.
• thermoplastically processable polymer mixtures based on starch can be found in EP-AI 0400531 and 0400532 and in PCT application WO 90/10671.
• the last-mentioned publication contains, in particular, extensive information on the mixing and the thermoplastic digestion of the polymer compounds used in the presence of water in suitable extruders, and the at least partial removal of the water from the mixture, expediently within the process step in the extruder.
• DE 4038732 relates to materials and / or molded parts based on thermomechanically digested starch in admixture with synthetic thermoplastic polymer compounds.
• These polymer-modified materials are produced by mixing native starch with aqueous Polymer dispersions of the synthetic thermoplastic polymer compounds and, if desired, further low molecular weight plasticizers are mixed, the multicomponent mixture is subjected to starch digestion at elevated temperatures and pressures with simultaneous intensive mixing and / or kneading to form the thermoplastically processable starch and, if desired, the homogenized polymer mixture is shaped.
• the water content introduced via the aqueous dispersions of the synthetic polymer compounds is an integral part of the process which is used and effective in the digestion process for starch digestion.
• suitable at least largely water-insoluble thermoplastic synthetic polymer compounds are, for example, emulsion (co) polymers such as polyvinyl esters, poly (meth) acrylates and / or corresponding copolyers. Also mentioned are polyesters, polyamides and / or polyurethane resins, it being possible to preferred thermoplastic polymer compounds which have polar groups and, where appropriate, combine oleophilic character with pronounced molecular components.
• DE 41 21 111 relates to materials and / or molded parts based on a correspondingly thermomechanically digested starch and synthetic thermoplastic polymer compounds, synthetic mix components now being used here which at least partly consist of raw materials based on renewable raw materials and of the class the polyester and / or polyamide are assigned.
• starches of natural origin contain the two main components, amylose and amylopectin.
• amylose is the smaller amount, as a rule it is below about 30% by weight and usually in the range from about 20 to 25% by weight (% by weight). -% each based on dry matter).
• Typical examples of these starch raw materials are the following examples - in the brackets below, the mean values for amylose wt.% TS: potato starch (22), wheat starch (24), corn starch (21).
• starches of vegetable origin with significantly higher amounts of amylose are also known, which in particular can be at least 50% by weight, for example 70% by weight or even 90% by weight, based on dry matter.
• Fat residues are saturated and straight-chain hydrocarbon residues of a sufficient length.
• Corresponding fat residues should accordingly contain at least 6 to 8 carbon atoms, preferably 10 or more carbon atoms in the straight-chain and saturated hydrocarbon residue, in order to achieve sufficient complexation through interaction with starch components with the formation of the channel inclusion compounds.
• thermoplastic starch In numerous related to the manufacture of thermoplastic starch In addition to the joint processing of starch, synthetic polymers and plasticizers, publications also mention the use of fatty derivatives. In this case, however, the function of the fat derivatives is exclusively that of a lubricant.
• WO 90/01043 describes the use of fats, waxes and paraffins as coating agents in the production and processing of TPS.
• the use of fat as a lubricant in the production of moldings based on TPS is described in DE 37 12029.
• Hardened fats are described in EP 404727 as processing aids of polymer materials based on destructurized starch. Further references to the combination of starch and fats can be found in US 4,016117 and in DE 1 717062.
• US 3,949145 describes the use of sorbitan onooleate for the production of agricultural films based on a degradable starch-based material.
• the teaching according to the invention also starts from the old task of providing thermoplastic materials which are largely based on natural raw materials and in particular contain natural starch as a particularly important component.
• These recyclable materials should be capable of being processed thermoplastically and, in the process, in the shaped body formed, should be characterized in particular by an optimization of the strength properties.
• the invention aims to show a way in which such optimized strength properties can be maintained in the shaped finished product over a longer period of time. Even if the known aging of such polymer composite materials based on starch with embrittlement and thus a drop in mechanical strength cannot be completely prevented, this deficiency, known per se, of the recyclable material mixtures based on TPS, which have been described to date, is to be largely alleviated can.
• the teaching according to the invention aims to show a way in which shaped articles with significantly improved dimensional stability can be obtained using starch-based materials of the type described.
• the teaching according to the invention wants to correspond to the above-described tasks of obtaining natural starch as the most important raw material component in the mixture of materials.
• the teaching according to the invention aims to ensure the practically complete rotting ability or the complete degradation of the polymer material by biological processes.
• the teaching according to the invention is also based on the above-described instruction to plasticize natural starch in a known manner with the use of plasticizing aids by thermomechanical digestion and, at the same time or at different times, to mix it intimately with other polymer components to be processed thermoplastically in such a way that a homogenization of the composite material takes place.
• these are at least predominantly based on raw materials based on renewable raw materials as mixture components with synthetic polymer compounds used - hereinafter also referred to as SPV.
• the invention wants to introduce the SPV components in the form of aqueous dispersions into the thermomechanical starch digestion, as is described in detail in DE 4038732. This enables a particularly economical 1-stage process for producing the starch-based composite materials described below.
• the invention relates to a shaped bend processable composite material - hereinafter also sometimes referred to as VM - based on thermomechanical with the addition of water and / or low molecular weight plasticizers digested starch (TPS) in a homogeneous mixture with synthetic polymer compounds (SPV).
• VM - shaped bend processable composite material
• thermomechanical with the addition of water and / or low molecular weight plasticizers digested starch (TPS) in a homogeneous mixture with synthetic polymer compounds (SPV).
• the characteristic of the teaching according to the invention is that in order to optimize the mechanical strength of the VM - determined by its tensile strength in accordance with DIN 53455 - the combination of the following parameters is observed:
• thermoplastically processable polymer compounds with lateral and / or terminal straight-chain and saturated hydrocarbon residues - hereinafter also referred to as "fat residues" - are used as the SPV component;
• These SPVs substituted with fat residues are homogenized with the TPS in such proportions that the content of the fat residues in the composite material (wt.% Fat residues based on anhydrous starch) is in the range from 0.5 to 7 wt.% .
• Preferred ranges for the weight ratio of the fat residues to the starch are in the range from 1 to 5% by weight and in particular in the range from about 2 to 4% by weight.
• the teaching according to the invention relates to the use of these thermoplastically processable composite materials based on TPS / SPV with selected and numerically determined weight ratios of the fat residues of the SPV for the production of moldings, for example for use as packaging materials such as films, bottles, cups, Boxes and the like.
• the teaching of the invention relates to the process for producing polymer-modified materials based on TPS and molded articles obtained therefrom in accordance with the definitions given above. Details of the teaching according to the invention
• the aim of the teaching according to the invention in its broadest and at the same time in its most concrete conception, is based on the intention of selecting and setting a specific structural parameter for the targeted interaction between the synthetic polymer compounds (SPV) used for processing with the starch to enable the TPS and the SPV.
• SPV synthetic polymer compounds
• the invention creates the possibility of optimizing the mechanical strength values of the composite material by selecting the "fat residues" which substitute the SPV in terms of type and quantity, based on the proportion of starch in the composite material.
• the individual SPV molecule is characterized by the presence of a plurality of the substituting fat residues in the sense of the definition according to the invention.
• the SPV used together with the starch in the sense of the inventive action are polymer components which are designed in a manner known per se and have an at least predominantly linear basic structure and are to be processed thermoplastically. Their molecular weights can fluctuate over a wide range. Suitable numerical values include, for example, molar masses in the range from 1.5 ⁇ 10 ⁇ to 10 ⁇ 10 ⁇ , preferred lower limit values for the molar mass of this SPV component being in the range from approximately 2 to 5 ⁇ 10 ⁇ . These SPV components are identified in the sense of the teaching according to the invention by the presence of a sufficient number of lateral and / or terminal fat residues.
• fat residue is understood to mean straight-chain and saturated hydrocarbon residues with at least 6 C atoms, preferably with at least 8 C atoms. It has been shown that the strength values in the composite material can be optimized by increasing the carbon chain length in the fat residue, so that preferred fat residues have at least 10 and preferably at least 12 carbon atoms on average.
• the respective SPV used can contain such fat residues of the same but also of different types. Preferred chain length ranges for these straight-chain fat residues are 6 to 32 carbon atoms and in particular 10 to 24 carbon atoms. The range of about 12 to 18 carbon atoms in at least a substantial proportion of the substituting fat residues present at the SPV can be of particular importance.
• olefinically mono- and / or polyunsaturated longer hydrocarbon residues can also be present as substituents on the, in particular, linear basic molecule of the SPV component.
• substituents on the, in particular, linear basic molecule of the SPV component For example, olefinically unsaturated Ciss, Cig, or also higher correspondingly olefinically unsaturated hydrocarbon radicals can be suitable substituents.
• the mechanical strengthening effect however, only the terminal aliphatic saturated portion of such an olefinically unsaturated substituent then obviously interacts with the starch to form the channel inclusion compounds.
• the strengthening effect of such substituents on the SPV and thus the adjustable increase in physical strength values is then restricted to the lower C number range of the terminally aliphatic saturated portion of such substituents. Accordingly, it can be preferred according to the invention to form at least a predominant proportion of the fat residues on the SPV in the form of aliphatic saturated fat residues of a higher carbon number. According to the invention, it is further preferred that the starch constitutes at least 40% by weight and preferably at least 50% by weight of the composite based on TPS / SVP -% by weight here based on the solid mixture free of water and low molecular weight plasticizing agents . Usually, the proportion of starch in the composite material will be approximately 50 to 80% by weight and preferably approximately 55 to 75% by weight -% by weight also calculated here as stated above.
• the starches preferred according to the invention are the inexpensively available starch materials with a limited amylose content, which here is below about 30% by weight and preferably in the range from about 15 to 25% by weight, based here on starch -Trocken ⁇ substance.
• the already mentioned starch raw materials based on potato, wheat and / or corn with the determination parameters for the aylose content given here are preferred feedstocks for the action according to the invention.
• the teaching of the invention is not restricted to these strengths.
• Alyose-rich starches are also suitable feedstocks.
• products can be obtained which are distinguished by further improved physical properties, for example by a further improvement in the form stability of the moldings produced, for example, by injection molding.
• SPV of the type of fat residues containing acrylate and / or methacrylate polymers are considered, but in particular SPVs containing lateral fat residues from the range of polyesters, polyamides, polyurethanes and / or polyvinyl alcohol esters, which are at least partially in theirs Ester groupings of long-chain fat residues contain.
• PVAc types modified with longer-chain fatty acid esters - copolymers of vinyl acetate and Monomers based on esters of vinyl alcohol with longer-chain fatty acids are particularly suitable representatives here.
• the fat residues can be present in minor amounts - based on the sum of the acid residues.
• Esters based on polyvinyl alcohol which at least partially contain fatty residues in the sense of the definition according to the invention - in particular from the acid groups used for ester formation - can be of particular importance from the following points of view: It has been shown that appropriate mixtures of TPS / SPV in the shaping processing can have a preferred position. Thus, according to process technology known per se, both films and moldings of higher material thickness, such as bottles, cups and the like, can be produced with good product properties.
• the teaching of the invention uses the elements of DE 4038732 used for the disclosure of the invention.
• the SPV substituted with fat residues in the sense of the current teaching can be used in the form of aqueous polymer dispersions which, together with this, are aqueous Phase are combined with the starch to be worked up to the thermoplastic state. If required, the required further low molecular weight plasticizers are mixed in.
• the finished composite materials are then produced by subjecting the multicomponent mixture at elevated temperatures and pressures with simultaneous intensive mixing and / or kneading in the starch digestion to form the composite material from TPS / SPV and, if desired, processing the homogenized polymer mixture in a shaping manner.
• the water content entered via the aqueous dispersion of the SPV becomes an integral part of the process which is used and effective in the digestion process for starch digestion.
• thermomechanical digestion of starch into the thermoplastic material also requires the use of water and / or lower organic plasticizers and / or auxiliaries in a manner known per se.
• lower polyfunctional alcohols such as ethylene glycol, propylene glycol, butanediol, glycerol and / or their ethers, in particular partial ethers, are suitable here.
• urea as an auxiliary of the type concerned here is also known and can be used according to the invention.
• the proportion of water in the mixture of substances to be worked up can be, for example, in the range from 5 to 40% by weight, preferably 5 to 30% by weight, based on the total mixture of substances.
• the proportion of the low-molecular organic auxiliary components used, such as glycerol, is usually at least about 3% by weight, advantageously in the range of at least about 5-10% by weight and in particular about 10 to 50% by weight, based in turn on the total mixture.
• the individual mixture components can be separated from the working device used in each case, for example the extruder, in the feed area and preferably fed continuously in the amount required in each case.
• the desired homogenization and mixing process takes place in the front departments.
• a processing line which is kept under product temperatures and pressures which lead to the desired thermo-mechanical starch digestion.
• the product temperatures are above 100 ° C. and preferably at or above 120 ° C., whereby working conditions in the range up to approximately 170 ° C. can be preferred at least in the final phases of the mixing and starch digestion process.
• the resulting working pressure usually corresponds to the intrinsic pressure of the water-containing mixture of substances at the specified working temperature.
• the residence times of the multicomponent mixture under the working conditions are generally not more than at most about 30 minutes, preferably at most about 20 minutes. It can be expedient to work with residence times of the multicomponent mixture at least in the range of the temperature and pressure conditions for starch digestion of about 0.5 to 10 minutes, preferably in the range of about 2 to 5 minutes.
• the homogenized polymer blend can be obtained as an extrudate and, for example, be used for shaping processing at a later time. However, it is also possible to use the polymer mixed product immediately after it has been obtained for the shaping processing to supply, as described in the publication cited at the beginning in CHIMIA (1987) loc. cit. for pure thermoplasticized starch.
• At least a portion of the water added to the mixing and digestion process is removed from the polyblend before its shaping processing - usually in the final stage of the digestion in the extruder.
• it applies to starch-based materials that the natural water contents of the starch are restored when they are stored under ambient conditions, which is known to be in the range of about 15 to 20% by weight, based here on starch.
• TPS thermoplastic starch
• TPS blends based on starch / SPV Potato starch (e.g. Südstär GmbH or Emsland-Starch) with a water content of 17-20% or wheat starch with a water content of 10-15%.
• Potato starch e.g. Südstär GmbH or Emsland-Starch
• wheat starch with a water content of 10-15%.
• Synthetic polymer compounds substituted with fat residues according to the specific definition given below.
• Polyols with a boiling point of at least 150 ° C. such as propylene glycol or preferably glycerol and, if appropriate, further auxiliaries such as urea and / or its derivatives, have been used as plasticizers.
• Aqueous polyvinyl acetate dispersion which, in the sense of the teaching of DE 40 38732, is subjected to potato starch and a low-molecular plasticizer (in particular glycerol) of the common extrusion and the thermomechanical digestion associated therewith.
• a low-molecular plasticizer in particular glycerol
• the comparable dispersion of a copolymer of vinyl acetate (VAc) and vinyl laurate (VL) in a molar ratio VAc: VL of 50: 2.5 is now used.
• VAc vinyl acetate
• VL vinyl laurate
• the syn- The synthetic polymer component contains the long-chain alkyl radicals of the vinyl laurate component as lateral substituents in a statistical distribution. At the same time, the biodegradability of this polymer is ensured biologically and thus its rotability.
• the synthetic polymer type used here for mixing with the starch and for its thermomechanical digestion corresponds to tests 2, 5 and 8, but with the modification that the molar ratio of VAc: VL is shifted to the numerical value of 47.8: 5.0.
• test groups are summarized in terms of their mixture components in terms of their type and amount, each grouped into groups of three to three, four to six and seven to nine.
• experiment numbers 1 to 9 show the numerically calculated values for the ratios "starch: polymer” in parts by weight to the ratio of "starch: fat (in the sense of the definition according to the invention)” in parts by weight and "Fat content (in the sense of the definition according to the invention)” in the polymer in% by weight.
• test numbers 2, 5 and 8 The optimization of the tensile strengths in test numbers 2, 5 and 8 results from the measured numerical values.
• the fat residues of this synthetic polymer based on PU are derived from rhicinoleic acid.
• Table 3 below shows the comparatively lowest strengths for this type of polymer, which can be explained by the lower tendency to form complexes.
• the proportion of steamed castor oil based on the PU melt (without water) is 12% by weight in the product used.
• Ciö / iß fatty alcohol is used here as a synthetic polymer component.
• the respective strength maxima are determined in test series with the 3 polymer types according to tests 10 to 18 - also determined here as tensile strength according to DIN 53455.
• the weight ratios of starch “fat” (in the sense of the definition according to the invention) "with the respective maximum strength of the test series.

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• Chemical & Material Sciences (AREA)
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• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Processes Of Treating Macromolecular Substances (AREA)
• Biological Depolymerization Polymers (AREA)

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Citations (5)

• 1993
  • 1993-10-05 DE DE19934333858 patent/DE4333858A1/de not_active Withdrawn
• 1994
  • 1994-09-27 JP JP7510594A patent/JPH09505613A/ja active Pending
  • 1994-09-27 WO PCT/EP1994/003229 patent/WO1995009888A1/de not_active Application Discontinuation
  • 1994-09-27 CA CA 2173583 patent/CA2173583A1/en not_active Abandoned
  • 1994-09-27 EP EP94927656A patent/EP0722475A1/de not_active Withdrawn

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