EP1056804A1 - Verfahren zur herstellung von thermoplastisch verarbeitbaren stärkeestern - Google Patents
Verfahren zur herstellung von thermoplastisch verarbeitbaren stärkeesternInfo
- Publication number
- EP1056804A1 EP1056804A1 EP99966849A EP99966849A EP1056804A1 EP 1056804 A1 EP1056804 A1 EP 1056804A1 EP 99966849 A EP99966849 A EP 99966849A EP 99966849 A EP99966849 A EP 99966849A EP 1056804 A1 EP1056804 A1 EP 1056804A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- carboxylic acid
- starch
- starch esters
- weight
- thermoplastically processable
- 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.)
- Withdrawn
Links
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
- C08L3/04—Starch derivatives, e.g. crosslinked derivatives
- C08L3/06—Esters
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
- C08B31/00—Preparation of derivatives of starch
- C08B31/02—Esters
- C08B31/04—Esters of organic acids, e.g. alkenyl-succinated starch
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/04—Oxygen-containing compounds
- C08K5/10—Esters; Ether-esters
- C08K5/101—Esters; Ether-esters of monocarboxylic acids
- C08K5/103—Esters; Ether-esters of monocarboxylic acids with polyalcohols
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/04—Oxygen-containing compounds
- C08K5/10—Esters; Ether-esters
- C08K5/11—Esters; Ether-esters of acyclic polycarboxylic acids
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L71/00—Compositions of polyethers obtained by reactions forming an ether link in the main chain; Compositions of derivatives of such polymers
- C08L71/02—Polyalkylene oxides
Definitions
- the invention relates to a process for the cost-effective production of plasticizer-containing, thermoplastically processable starch esters from carboxylic acid reaction mixtures.
- starch esters with medium degrees of substitution by heterogeneous esterification reaction in an alkaline aqueous phase, the starch esters being present as a slurry after the reaction and only being filtered and washed (EP 0 603 837).
- a disadvantage of this variant is the side reaction of the carboxylic acid anhydrides used for the esterification with the aqueous alkali solution, as a result of which considerable excess shots of carboxylic anhydrides are required. Furthermore, the amount of aqueous carboxylic acid solution formed is less than the previously described variants, but a cost-intensive workup is also necessary.
- starch esters The preference for working up by precipitation and washing results from the properties of the starch esters. Starch acetates cannot be melted without decomposition and discolouration reactions occurring in parallel, and all starch esters tend to break down molecular weight and discolouration in the presence of strongly acidic or alkaline catalyst residues in the melt.
- Precipitation can be separated by precipitation and washing processes, and the cleaned starch esters are only exposed to a moderate thermal load in the drying step.
- US Pat. No. 2,376,378 describes a process for the production of starch esters, wherein after the esterification reaction has ended, the major part of the carboxylic acid is distilled off from the starch ester-containing reaction mixture and a remaining part of the carboxylic acid is stripped off by steam.
- This method can only be used if high-boiling solvents or other substances which are at least partially miscible with the starch ester and remain in the product, so that solidification of the concentrated reaction mixture is reliably avoided.
- Distilling off the total amount of carboxylic acid from highly viscous starch ester reaction mixtures is an extremely energy-intensive and time-consuming process, and starch esters worked up in this way show considerable discoloration.
- Another problem is the need to decompose the catalyst used for the esterification in such a way that the decomposition products can either also be distilled off or at least do not interfere with the intended further processing steps and applications.
- thermoplastically processable starch esters restricts the selection options of the plasticizers for the thermoplastically processable end product to a considerable extent, since with such a procedure basically only substances can be used which can react with the substances to be plasticized with the residual carboxylic acid.
- an adaptation of the range of properties of the thermoplastically processable starch esters to certain areas of application is limited from the outset.
- starch esters for example by spray drying or flash evaporation of the carboxylic acids which serve as solvents, from reaction mixtures containing carboxylic acids containing starch esters, optionally followed by fine drying, for example by mill drying under vacuum to residual carboxylic acid contents below 0.1% by weight.
- the starch esters shown in this way are powders made of glassy, massive particles with no inner surface or porosity, the size of which depends on the grinding.
- starch esters produced in this way are primarily suitable for the production of compounds with natural fibers or other Ren, mainly organic, cellulose-containing fillers, while incorporation of plasticizers is difficult because even in double-shaft kneaders with intensive shear, the glassy starch ester particles are not completely penetrated by the plasticizer.
- Thermoplastic processable starch ester / plasticizer compounds produced in this way always have a considerable proportion of specks made of starch ester particles which are difficult to melt and have an extremely low plasticizer content, so that it is not possible to produce films or high-quality injection molded parts therefrom.
- the object of the invention is to avoid the disadvantages of the prior art and to propose a process for the cost-effective production of homogeneous, plasticizer-containing, thermoplastic speck-free processable starch esters from carboxylic acid reaction mixtures, with better control through expanded options from a range of suitable high-boiling plasticizers or plasticizer mixtures of product and processing properties is made possible.
- the residual carboxylic acid contents can be reduced to values below 0.1% by weight by appropriate design of a mixer or kneader, for example via vacuum degassing zones.
- the predried starch esters contain less than 1% by weight of residual carboxylic acid, it is no longer possible to incorporate plasticizers homogeneously into the then very compact starch ester structures with reasonable effort and without significant damage to the polymer structure.
- a suitable one Discharge device such as a rotary valve is discharged from the predrying unit.
- the starch ester which preferably contains 2 to 15% by weight of carboxylic acid, is mixed with suitable plasticizers, such as, for example, polyalkylene glycols, citric acid esters, glycerol di- or triestem or diesters of C 4 to C dicarboxylic acids in a suitable mixing unit with or several degassing zones, such as a double-kneader with one or more vacuum degassing zones, mixed intensively and freed from the carboxylic acids still present at temperatures between 100 to 220 ° C, preferably between 120 to 200 ° C, the vacuum degassing zones either with a uniform or with a graduated vacuum between 0.02 to 900 mbar, preferably between 0.1 to 250 mbar.
- suitable plasticizers such as, for example, polyalkylene glycols, citric acid esters, glycerol di- or triestem or diesters of C 4 to C dicarboxylic acids in a suitable mixing unit with or several degassing zones, such as
- the softened, thermoplastically processable starch esters of C 2 - to C 18 -, preferably the C 2 - to C 7 - monocarboxylic acids or mixed esters thereof, produced in the manner described according to the invention, are crystal-clear to slightly yellowish colored granules with residual carboxylic acid contents below 0.1% by weight. %.
- Starting starches can be both native starches, such as corn, wheat, potato, rice, peas, tapioca, waxy maize or high amylose-containing corn, potato or pea starches, and also their derivatives, such as hydroxyethylated, hydroxypropylated, acetalized, phosphorylated , sulfated, oxidized, carboxyalkylated, nitrated starches, allyl starches, xanthate starches with degrees of substitution of 0.01-1.0, pre- preferably 0.05-0.8 can be used in a naturally moist or pre-dried state.
- native starches such as corn, wheat, potato, rice, peas, tapioca, waxy maize or high amylose-containing corn, potato or pea starches
- derivatives such as hydroxyethylated, hydroxypropylated, acetalized, phosphorylated , sulfated, oxidized, carboxyalkylated, nitrated starches,
- a slurry of 1600 g wheat starch (13% by weight moisture), 2500 g glacial acetic acid and 2800 g acetic anhydride is acetylated in a 10 l kneading reactor at 180 ° C. and a pressure of approx. 5 bar for 12 hours.
- the highly viscous starch acetate reaction mixture is sprayed at 180 ° C. under a pressure of 25 bar through an annular gap nozzle with a gap of 0.25 mm into a 1 m 3 vacuum container heated to 60 ° C. and evacuated to 10 mbar.
- the resulting acetic acid-acetic anhydride vapors are fed to the vacuum pump via three heated pipes attached to the top of the vacuum container via a filter, which is also heated to 60 ° C, and condensed on its pressure side.
- thermoplastically processable starch ester plasticizer compound is a very pale yellowish, clear granulate with a residual acetic acid content of less than 0.1% by weight, which can be easily processed into high-quality injection molded parts and foils.
- a slurry of 1600 g pre-dried corn starch (5.5% by weight moisture) and 2900 g of acetic anhydride is degassed in a temperature-controlled ball mill for about one minute at 15 ° C. and OJ bar and then activated for 3 minutes at 10 bar and 60 ° C.
- the activated slurry is continuously heated to 100 ° C. by means of a pump and a preheater and acetylated in a subsequent continuous kneading reactor at 160 ° C. and 3.2 bar with an average residence time of 20 min.
- the highly viscous starch acetate reaction mixture is sprayed at 145 ° C. and under a pressure of 2.1 bar through an annular gap nozzle with a 1 mm gap width into a 1 m 3 vacuum container heated to 100 ° C. and evacuated to 80 mbar.
- the resulting acetic acid-acetic anhydride vapors are fed to the vacuum pump via three heated pipes attached to the top of the vacuum container via a filter that is also heated to 100 ° C and condensed on its pressure side.
- thermoplastically processable starch ester / plasticizer compound is a slightly yellowish, glass-clear granulate with a residual acetic acid content below 0J% by weight, which can be easily processed into high-quality injection molded parts.
- a slurry of 1600 g of hydroxyethylated (DS ⁇ 0.05), high amylose-containing maize starch (approx. 70% by weight amylose, 13% by weight moisture) and 3800 g acetic anhydride is initially in a continuous volume flow of 3.5 kg / h an ultraturax at normal pressure and 80 ° C (average residence time approx. 2.5 min), heated to 150 ° C via a preheater and then in a continuous high-viscosity Stirred reactor at 150 ° C. and 3 bar with an average residence time of approx. 60 min.
- the highly viscous starch acetate reaction mixture is sprayed at 160 ° C. and under a pressure of 3.2 bar through a nozzle with a 2.5 mm bore into a 1 m 3 vacuum container heated to 40 ° C. and evacuated to 25 mbar.
- the resulting acetic acid-acetic anhydride vapors are fed to the vacuum pump via three heated pipes attached to the top of the vacuum container via a filter, which is also heated to 40 ° C, and condensed on its pressure side.
- thermoplastically processable starch ester / plasticizer compound is a slightly yellowish, glass-clear granulate with a residual acetic acid content of less than 0.1% by weight, which can be easily processed into high-quality injection molded parts.
- a slurry of 1600 g phosphorylated potato starch (DS ⁇ 0.02) with a moisture content of 16.5% by weight in a mixture of 3000 g glacial acetic acid, 3000 g acetic anhydride and 700 g butyric anhydride is in a discontinuous 16 l kneading reactor at 170 ° C and 4 bar esterified over 12 h.
- the highly viscous starch ester reaction mixture is sprayed at 200 ° C. and under a pressure of 25 bar through a slot nozzle with a 0.5 mm gap width into a 1 m 3 vacuum container heated to 80 ° C. and evacuated to 0.5 mbar.
- the resulting carboxylic acid-carboxylic anhydride vapors are also opened via three heated pipes attached to the top of the vacuum container 80 ° C heated filter supplied to the vacuum pump and condensed on its pressure side.
- thermoplastically processable starch ester / plasticizer compound is a slightly yellowish, glass-clear granulate with a residual acetic acid content of less than 0.1% by weight, which can be easily processed into high-quality injection molded parts.
- the activated slurry is transferred to a 5 l kneading reactor, heated to 170 ° C. and esterified at this temperature and a pressure of approx. 5 bar for 60 minutes.
- the highly viscous starch ester reaction mixture is passed for 10 minutes at 200 ° C.
- thermoplastically processable starch ester / plasticizer compound is a slightly yellowish, glass-clear granulate with a residual carboxylic acid content of less than 0.1% by weight, which can be easily processed into high-quality films and injection molded parts.
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Biochemistry (AREA)
- Materials Engineering (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE1998157996 DE19857996A1 (de) | 1998-12-16 | 1998-12-16 | Verfahren zur Herstellung von thermoplastisch verareitbaren Stärkeestern |
DE19857996 | 1998-12-16 | ||
PCT/DE1999/003939 WO2000036007A1 (de) | 1998-12-16 | 1999-12-10 | Verfahren zur herstellung von thermoplastisch verarbeitbaren stärkeestern |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1056804A1 true EP1056804A1 (de) | 2000-12-06 |
Family
ID=7891259
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP99966849A Withdrawn EP1056804A1 (de) | 1998-12-16 | 1999-12-10 | Verfahren zur herstellung von thermoplastisch verarbeitbaren stärkeestern |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP1056804A1 (de) |
DE (1) | DE19857996A1 (de) |
WO (1) | WO2000036007A1 (de) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102008035401B4 (de) * | 2008-07-29 | 2011-04-21 | List Holding Ag | Verfahren zur kontinuierlichen katalytischen Azetylierung von Polysacchariden |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2376378A (en) * | 1941-09-20 | 1945-05-22 | John D Murray | Acetylation process and product |
DE4114185C1 (de) * | 1991-04-30 | 1993-02-04 | Battelle-Institut E.V., 6000 Frankfurt, De | |
EP0638609B1 (de) * | 1993-08-04 | 2001-03-21 | Buna Sow Leuna Olefinverbund GmbH | Bioabbaubare, thermoplastisch verformbare Materialien aus Stärkeestern |
EP0729476A1 (de) * | 1993-11-19 | 1996-09-04 | Woodstone Foods Corporation | Verfahren zur acylierung der staerke |
DE4423681A1 (de) * | 1994-06-23 | 1996-01-04 | A U F Analytik Umwelttechnik F | Verfahren zur Herstellung partiell substituierter Stärkeacetate |
DE4425688A1 (de) * | 1994-07-14 | 1996-01-18 | A U F Analytik Umwelttechnik F | Verfahren zur Herstellung von hochsubstituierten Stärkeacetaten |
US5629416A (en) * | 1995-03-31 | 1997-05-13 | National Starch And Chemical Investment Holding Corporation | Method of preparing crosslinked starch esters |
US5710269A (en) * | 1996-01-16 | 1998-01-20 | Hoechst Celanese Corp. | Method of making starch acetate using an acid catalyst |
DE19633474A1 (de) * | 1996-08-20 | 1998-02-26 | Buna Sow Leuna Olefinverb Gmbh | Verfahren zur Herstellung biologisch abbaubarer Stärkeester |
-
1998
- 1998-12-16 DE DE1998157996 patent/DE19857996A1/de not_active Withdrawn
-
1999
- 1999-12-10 EP EP99966849A patent/EP1056804A1/de not_active Withdrawn
- 1999-12-10 WO PCT/DE1999/003939 patent/WO2000036007A1/de not_active Application Discontinuation
Non-Patent Citations (1)
Title |
---|
See references of WO0036007A1 * |
Also Published As
Publication number | Publication date |
---|---|
WO2000036007A1 (de) | 2000-06-22 |
DE19857996A1 (de) | 2000-06-21 |
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