DE102008028544A1 - Thermoplastic molding composition, useful for preparing molded parts that are useful as plate, film and bristle, comprises a matrix phase of polysaccharide ester e.g. cellulose acetate, in nanoscalic filler e.g. hectorite or saponite - Google Patents

Abstract

Thermoplastic molding composition comprises a matrix phase of at least one polysaccharide ester in at least one nanoscalic filler, where the molding composition is free of plasticizers. Independent claims are included for: (1) a method for preparing plasticizer-free thermoplastic molding composition comprising homogenously mixing the nanoscalic filler, under the influence of mechanical shearing forces, with the matrix phase; (2) molded parts prepared from the above molding composition; and (3) a method for preparing the molded parts comprising processing the above thermoplastic molded composition by extrusion (preferably profile and film extrusion), injection molding, injection blow molding, pressing or melt spinning.

Description

The The invention relates to a thermoplastic molding composition comprising a matrix phase from a polysaccharide ester and a nanoscale incorporated therein Contains filler, wherein the molding composition free of Softeners is. Likewise, the invention relates to a method for Production of such molding compositions. The invention also relates From these molding compounds produced moldings and a corresponding Production method. Use find the moldings as high-strength and / or highly stressed construction components, as plates, films, Bristles, monofilaments or fibers.

Polysaccharide esters, such as. As starch esters or cellulose esters, unlike most petroleum-based polymers, such as polypropylene, polyethylene, polyamides, etc. are not melt-processable without the addition of plasticizers by conventional methods such as extrusion or injection molding. For starch itself, the term thermoplastic starch (TPS) was coined. TPS denotes starch compounds which contain plasticizers, such as water, glycerol, sorbitol or the like, and are therefore thermoplastically processable ( EP 0 397 819 ). To achieve thermoplastic processability of starch esters plasticizers are also usually added here z. B. glycerol triacetate ( US 5,869,647 ).

Celluloseester, u. a. Cellulose acetate (CA), cellulose butyrate (CB), cellulose acetate butyrate (CAB), which is commercially available for thermoplastic processing, injection molding in particular, also contain plasticizers, which are mostly based on phthalic acid esters. significant Manufacturers are Eastman Co. with the Tenite and Albis range Plastics GmbH with Cellidor, whereby the products by different Plasticizer content in the range of 5 to 30% differ. Lower Plasticizer contents are offered on longer-chain esters, z. B. CAB, which due to their molecular structure a lighter Processing, compared with shorter-chain, z. B. CA, allow.

The the prior art use of plasticizers allows the thermoplastic processing of polysaccharide esters on an industrial scale, however, just by the plasticizing Effect, the mechanical properties of the final product (extrudate or injection molded part) down. This is evident when looking at maximums commercial cellulose-based products (starch-based lie underneath). For the product Biograde 200C from FKur be with tensile strengths in the range of 80 MPa and Tensile Moduli of 3.4 GPa described such maximum values. Otherwise usual Values are far below and are in the range of 40 MPa or 1.5 GPa. Another disadvantage of plasticized systems exists in that plasticizer by which they are characterized as plasticizers high mobility have a migration tendency in the finished molded part, which can lead to embrittlement of the product. The disadvantages mentioned are achieved by the invention overcome thermoplastic bio-based material.

outgoing It was an object of the present invention to provide moldings, which do not have the said disadvantages in the prior art, d. H. are thermoplastically processable and yet high strength and have rigidity.

These The object is achieved by the molding compound having the features of the claim 1, the process for its preparation with the features of the claim 9, the molding with the features of claim 12 and the method for the production of the molding according to claim 15. Claim 16 uses the invention listed.

According to the invention a thermoplastic molding composition is provided which is a matrix phase comprising at least one polysaccharide ester in which at least a nanoscale filler is included. The inventive Molding material contains no plasticizer.

Surprisingly show nanoscale fillers, especially nanoscale Phyllosilicates, after incorporation into the matrix phase, for. B. by Shearing at elevated temperatures, a thermoplastic processing permitting effect without any apparent softening effect Produce effect in the final product. As in the examples closer can be described in injection molded standard specimens Tensile strengths of 178 MPa and tensile moduli of 8.4 GPa can be achieved. In addition, the mobility of nanoscale fillers negligible in the finished molding, as from the absence the plasticizing effect. Further advantages of the invention Materials are based on a reduction in gas and liquid permeability, an increase in flame retardancy and an increase the heat resistance.

Among the commonly used in the art plasticizers for polysaccharide esters include o-, m-, p-phthalic acid, benzoic acid, trimellitic acid, benzenesulfonic acid, aliphatic dicarboxylic acids (glutaric acid, adipic acid, azelaic acid, sebacic acid), aliphatic monocarboxylic acids (saturated fatty acids C2-C18), oleic acid, linoleic acid, linolenic acid, ricinoleic acid), acrylic acid, phosphoric acid and citric acid. In particular, plasticizers for polysaccharide esters known in the art are understood to mean the following groups of substances:

From the group of glycerides:

• • mono-, di- and triesters,
• • in the di- and tri-stems also compounds with mixed Estergruppen,
• • Triesters especially glycerol triacetate and glycerol tripropionate
• • Glycerides with ester residue groups that belong to the linear and branched aliphatic alkyl groups and the olefinic Residual groups include, with C2-C36 carbon atoms in the alkyl chains;

From the group of citrates:

• • mono-, di- and triesters,
• • in the di- and tri-stems also compounds with mixed Estergruppen;

From the group of phthalates:

• • dimethyl phthalate,
• Diethyl phthalate,
• Dibutyl phthalate,
• • butyl benzyl phthalate,
• Ethylene glycol monoethyl phthalate, etc .;

Esters of trimellitic acid:

• • trimethyl trimellitate,
• Triethyl trimellitate,
• Tri- (2-ethylhexyl) trimellitate, etc .;

Aliphatic dicarboxylic acid esters

• • such as di- (2-ethylhexyl) azelate, etc .;

From the group of phosphoric acid esters:

• Tributyl phosphate,
• Tributoxyethyl phosphate,
• Triphenyl phosphate,
• Tricresyl phosphate,
• Cresyl diphenyl phosphate,
• 2-ethylhexyldiphenyl phosphate, etc .;

Esters of ricinoleic acid:

• • 12-hydroxyacetyl-9-octadecenoic acid methyl ester Etc.

Preferably the polysaccharide ester is selected from the group of Cellulose esters, in particular cellulose acetate, cellulose butyrate and / or Cellulose acetate butyrate.

Of the Polysaccharide ester preferably has a degree of substitution (DS) from 1.7 to 3, more preferably from 2.3 to 2.7.

Of the used nanoscale filler is preferably selected from the group consisting of modified or unmodified Phyllosilicates and their mixtures, in particular from the class the phyllosilicates, more preferably smectic phyllosilicates Type, in particular Montmorillonite, Saponite, Hectorite, Halloysite, Beidellite, Vermiculite, Stevensite, Montronite and / or Fluorhectorite.

Of the at least one filler preferably has a cation exchange capacity from 30 to 250 meq (milliequivalents) per 100 g.

Of the Weight fraction of the matrix phase, based on the molding composition is preferably between 99.99 to 60 wt.%, preferably between 99.9 and 75% by weight, and more preferably between 99.9 and 80% by weight.

Of the Weight fraction of the at least one nanoscale filler, based on the total molding composition, is preferably between 0.01 to 40% by weight, preferably between 0.1 and 25% by weight and more preferably between 0.1 and 20% by weight.

The at least one nanoscale filler preferably has an average particle size d ₅₀ between 0.1 nm and 10 μm, preferably between 2 μm and 8 μm.

According to the invention as well as a process for producing a plasticizer-free thermoplastic Formmasse, as described above, provides bereitge, wherein the at least one nanoscale filler under the action of mechanical shear forces with the matrix phase homogeneous is mixed. Due to the mechanical shear forces doing a comminution of at least a portion of the nanoscale filler.

The Mixing is preferably carried out at temperatures between 0 ° C. and 450 ° C, preferably between 100 ° C and 350 ° C and more preferably between 150 ° C and 300 ° C.

A preferred embodiment of the preparation of the invention Material is as follows. A defined amount Cellulose acetate powder (CA) with a DS in the range of 2.3 to 2.7 is used with nanoscale phyllosilicates, z. B. unmodified Montmorillonite (MMT) at room temperature with the help of a fast dry blender for 1 to 10 minutes dry premixed and so a premix produced. Typical MMT contents are from 0.5 to 20% by mass MMT, based on the total mass of CA and MMT. Subsequently, will the premix in a kneader at temperatures in the range of 180 ° C. up to 300 ° C at rotor speeds between 10 and 350 rotations Homogenized per minute (rpm). Preference is given to temperatures in the range 200 ° C to 300 ° C and rotational speeds between 50 rpm and 250 rpm. Mixing times are in the range between 5 minutes and 60 minutes, preferably between 10 minutes and 30 minutes. To further Homogenization is an extrusion on a co-rotating Twin-screw extruder at temperatures between 200 ° C and 350 ° C and a screw speed between 10 and 350 rpm. The extrudate is mixed with a commercial granulator crushed and injection molded. The cylinder temperatures are between 230 ° C and 250 ° C and mold temperatures between 90 ° C and 110 ° C.

According to the invention also provided moldings, which from the previously described Molding material can be produced.

The moldings according to the invention preferably have a tensile strength of at least 90 MPa, preferably at least 105 MPa, more preferably at least 130 MPa and particularly preferably at least 150 MPa. These tensile strengths are reflected on a test rod DIN EN ISO 527-1 type 5A determined at 23 ° C and 50 relative humidity.

Furthermore, the moldings according to the invention preferably have a tensile modulus of at least 4.5 GPa, preferably at least 5.0 GPa, more preferably at least 5.5 GPa, and most preferably at least 6.0 GPa. The tensile modulus is measured on a test rod DIN EN ISO 527-1 type 5A determined at 23 ° C and 50% relative humidity.

Farther is a method for producing the above-described molded part provided in which a molding composition, as described above was, is processed thermoplastically. The thermoplastic processing takes place here preferably by extrusion, in particular profile and film extrusion, injection molding, injection blow molding, pressing, or melt spinning.

use find the moldings of the invention as a high strength and / or highly stressed construction component, as a plate, foil, Bristle, monofilament or fiber in the field of transport, Industrial equipment, Machinery and equipment, Household appliances, Tank construction, medical technology, electrics and electronics.

Based The following examples are intended to illustrate the invention Subject to be explained in more detail, without this restrict to the specific embodiments shown here to want.

example 1

Cellulose acetate powder L60 / 90 from Eilenburg with a magnetic resonance determined DS of 2.63 is pre-dried overnight at 80 ° C in a vacuum oven. With a fast-rotating kitchen mixer, a premix is prepared which contains 2.5% by weight of the MMT Dellite LVF from the company Laviosa SpA., Based on the total mass, and which is stored overnight in a polyethylene bag. The premix consisting of 120 g of dry CA and 3.08 g of LVF is homogenized in a W 350 E kneader from the company Brabender for 20 min at 230 ° C. and a speed of 150 rpm. After discharge and comminution of the compound, it is further homogenized in a co-rotating twin-screw extruder (Haake Minilab) at 230 ° C. and 200 rpm, discharged and granulated (granulator SGS 25-E4 from Scheer). Subsequent injection molding takes place on a Haake Minijet at a cylinder temperature of 230 ° C and a mold temperature of 110 ° C. There are test rods after DIN EN ISO 527-1 type 5A subsequently produced at 23 ° C and 50% relative humidity in an air-conditioned laboratory on a Zwick 1445 testing machine DIN EN ISO 527-1 being checked.

Example 2

As Example 1, only with an MMT content of 5 mass%, d. H. 6.3 g MMT to 120 g CA.

Example 3

As Example 1, only with an MMT content of 10% by mass, d. H. 13.3 g MMT to 120 g CA.

Example 4

As Example 1, only with an MMT content of 20% by mass, d. H. 30 g MMT to 120 g CA.

In Table 1, the mechanical properties of inventive materials according to Examples 1 to 4 are compared with the commercially available material Biograde 200C (FKur GmbH), which has a plasticizer compared. Here, the tensile strength, the tensile modulus and the elongation at break were compared. The determination was made according to DIN EN ISO 527-1 type 5A , Table 1 material Tensile strength [MPa] Tensile modulus [GPa] Elongation at break [%] CA with 2.5% LVF 164 ± 15 6.0 ± 0.4 3.9 ± 0.2 CA with 5% LVF 178 ± 6 8.4 ± 0.1 2.6 ± 0.1 CA with 10% LVF 109 ± 2 4.8 ± 0.1 3.2 ± 0.2 CA with 20% LVF 95 ± 14 6.1 ± 0.5 1.9 ± 0.2 Biograde 200C 82 3.37 8.2

Based The values are impressively demonstrated that the inventive Molded parts have significantly better strength and stiffness.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• EP 0397819 [0002]
• US 5869647 [0002]

Cited non-patent literature

• - DIN EN ISO 527-1 Type 5A [0021]
• - DIN EN ISO 527-1 Type 5A [0022]
• - DIN EN ISO 527-1 type 5A [0026]
• - DIN EN ISO 527-1 [0026]
• - DIN EN ISO 527-1 type 5A [0030]

Claims (16)

Thermoplastic molding composition comprising a matrix phase from at least one polysaccharide ester in which at least one nanoscale Filler is included, wherein the molding composition free of plasticizers is. Molding composition according to claim 1, characterized that the at least one polysaccharide ester comprises at least one cellulose ester, preferably cellulose acetate, cellulose butyrate and / or cellulose acetate butyrate. Molding composition according to one of the preceding claims, characterized in that the polysaccharide ester has a degree of substitution (DS) from 1.7 to 3, preferably from 2.3 to 2.7. Molding composition according to one of the preceding claims, characterized in that the at least one filler is selected from the group consisting of modified and / or unmodified phyllosilicates, preferably from the class the phyllosilicates, more preferably smectic phyllosilicates Type, in particular Montmorillonite, Saponite, Hectorite, Halloysite, Beidellite, Vermiculite, Stevensite, Montronite and / or Fluorhectorite. Molding composition according to one of the preceding claims, characterized in that the at least one filler a cation exchange capacity of 30 to 250 meq (milliequivalents) per 100 g. Molding composition according to one of the preceding claims, characterized in that the weight fraction of the matrix phase based on the molding composition between 99.99 to 60 wt .-%, preferably between 99.9 and 75 wt .-%, particularly preferably between 99.9 and 80 wt .-% is. Molding composition according to one of the preceding claims, characterized in that the weight proportion of the at least one nanoscale filler based on the molding compound between 0.01 to 40 wt .-%, preferably between 0.1 and 25 wt .-%, especially preferably between 0.1 and 20 wt .-% is. Molding composition according to one of the preceding claims, characterized in that the at least one nanoscale filler has an average particle size d ₅₀ between 0.1 nm and 10 microns, preferably between 2 microns and 8 microns Process for the preparation of a plasticizer-free thermoplastic molding composition according to any one of the preceding claims, wherein the at least one nanoscale filler under the action of mechanical shear forces with the matrix phase homogeneous is mixed. Method according to the preceding claim, characterized characterized in that by the mechanical shear forces a comminution of at least part of the nanoscale filler he follows. Method according to one of the two preceding claims, characterized in that the mixing at temperatures between 0 ° C and 450 ° C, preferably between 100 ° C and 350 ° C, more preferably between 150 ° C and 300 ° C is performed. Molded part, producible from a molding compound after a of claims 1 to 8. Molded part according to the preceding claim, characterized by a tensile strength of at least 90 MPa, preferably at least 105 MPa, more preferably at least 130 MPa, more preferably at least 150 MPa, measured on a test rod according to DIN EN ISO 527-1 type 5A at 23 ° C and 50% relative humidity. Molding according to one of the two preceding claims, characterized by a tensile modulus of at least 4.5 GPa, preferably at least 5.0 GPa, more preferably at least 5.5 GPa, especially preferably at least 6.0 GPa, measured on a test rod according to DIN EN ISO 527-1 type 5A at 23 ° C and 50% relative Humidity. Process for producing a molded article according to one of claims 12 to 14, wherein a molding compound according to a of claims 1 to 8 thermoplastic, in particular by Extrusion, in particular profile and film extrusion, injection molding, Injection blow molding, pressing, or melt spinning is processed. Use of a molding according to one of the claims 12 to 14 as a high-strength and / or highly stressed construction component, as a plate, foil, bristle, monofilament or fiber in the fields Transport, Industrial Equipment, Machinery and Plant construction, household appliances, container construction, medical technology, Electrics and electronics.