DE4122556A1 - Thermoplastic polymer mixts. with improved processability, etc. - contains cyclic organo-silicon cpd., pref. octa:phenyl-cyclo:tetra:siloxane, as solid, anticorrosive processing additive, etc. - Google Patents

Abstract

Mixts. of thermoplastic polymers and organosilicon cpds. (I), contg. at least one cyclic organo-Si cpd. of formula (II) in amts. of 0.01-5wt.% w.r.t. polymer. In (II), R1, R2 are alkyl or aryl; n is 3-10. Pref. (II) is octaphenyl cyclotetrasiloxane (IIA) in amts. of 0.1-1wt.%; (I) also contain fillers, reinforcing agents and/or pigments. USE/ADVANTAGE - (I) are useful for the prodn. of electronic components and in the food industry (claimed). The invention provides new processing additives (II) for thermoplastics, which are colourless, harmless, pref. solid at room temp., anticorrosive and easily metered (contrast prior-art silicone additives); (II) improve the distribution of components in polymer mixts. (resulting in improved mechanical and flow properties, etc.), and act as effective mould release agents; (II) are esp. useful in processing high temp.-resistant polymers such as PPO, PEEK, PPS polyarylate, etc..

Description

The present invention relates to mixtures of thermoplastic polymers and ring-shaped organosilicon compounds.

It is known that the processability and properties of Thermoplastic mixtures through the addition of certain processing aids can be improved.

These known additives are auxiliaries that u. a. the Processing speed by reducing the viscosity, through improved Distribution of individual mixture components or by reducing the Adhesion to metal surfaces should increase. Still observed one occasionally finds that the addition of processing aids is an improvement the mechanical parameters, for example the elongation at break.

The processing aids used in practice belong to the various substance classes.

Examples of such substance classes are e.g. B. long chain fatty acid salts, Fatty acid esters, waxes, ethylene oxide and propylene oxide polymers, silicone oils. Further examples and application notes can be found, for example, in Encyclopedia of Polymer Science and Engineering, Volume 14, page 411, release Agents and in R. Gächter, H. Müller Kunststoff-Additive, 2nd edition Carl Hanser Verlag, Munich, Vienna, 1983, pages 309-353.  

The known processing aids have a number of disadvantages if they should be used to process high-performance plastics. For example, when processing the substance class of polyarylene ethers, Polyarylene ether ketones or polyaramides are generally very high Processing temperatures are applied. At these high temperatures form processing aids from the group of long-chain fatty acid salts, Fatty acid esters, waxes, ethylene oxide and propylene oxide polymers in a noticeable amount Dimensions of decomposition products. These decomposition products can become one undesirable discoloration of the polymer melt, to form black Particles and to reduce the application properties of the Lead polymers.

For this reason, various processing aids have been proposed been used for the thermoplastic processing of high-performance plastics can be used.

It is known that polyarylene ether ketone melts through the use of Talc obtained good sliding properties (EP-B 01 82 580). Talc is very temperature resistant, suitable as a filler and gives the polymer melt good sliding properties at the same time. Our own experiments have shown that the Adding talcum improves the melt processability. On the other hand, the Using talcum the lack of transparency is very detrimental. The production transparent molded parts or foils are not possible. Furthermore, the It is not possible to manufacture fibers because the spinning process is low in particles Polymer melting required. In the case of molded parts, the impact and Notched impact strength through the addition of talc.

It is also known that high molecular weight fluoropolymers perform well in the Have polymer melt suspended and improve processability. The disadvantage here is that none due to the lack of transparency transparent moldings or foils can be produced.  

Such fluoropolymers also decompose in the case of, for example, for Polyarylene ether ketones typically used processing temperatures of 350 to 420 ° C. The decomposition of fluoropolymers creates toxic gases released. These resulting decomposition products cause strong corrosive attack on those coming into contact with the polymer melt Metal parts.

It is also known that organosilicon compounds are considered temperature resistant Processing aids are suitable in principle. For example, those in the In practice, silicone oils used good lubricants while maintaining a high level Temperature resistance. A disadvantage of silicone oils, however, are their unfavorable ones application properties. Due to the viscous or sticky Consistency makes the exact dosage very difficult and a homogeneous distribution with polymer powder or granulate, for example, is difficult to carry out.

Generally, silicone oils cause extrusion processing of polymers, e.g. B. also polyarylene ether powders feed difficulties.

The present invention is therefore based on the object of a method for Processing of thermoplastic mixtures to provide the listed Does not have disadvantages.

The invention thus relates to mixtures of thermoplastic polymers and 0.01 up to 5% by weight, preferably from 0.1 to 1% by weight, of processing aids - based on polymer used - based on at least one cyclic Organosilicon compounds of the formula (I)

wherein R ¹ and R ^{2 are} independently the same or different alkyl or aryl groups, preferably methyl and phenyl and n is an integer from 3 to 10, preferably 3 to 4.

Suitable compounds are, for example

[(CH₃) ₂SiO] ₃, [(CH₃) ₂SiO] ₄, [(CH₃) (C₂H₅) SiO] ₄, [(CH₃) (C₂H₅) SiO] ₆, [(C₂H₅) ₂SiO] ₅,
[(C₆H₅) ₂SiO] ₃, [(C₆H₅) ₂SiO] ₄, [(C₆H₅) (CH₃) SiO] ₄, [(C₆H₅) (C₂H₅) SiO] ₃, [(C₆H₅) (C₂H₅) SiO] ₄

alone or in mixtures. Such and other suitable ones Compounds are described, for example, in W. Noll, "Chemie und Technologie der Silicone ", (Verlag Chemie 1960). Preferred is Octaphenylcyclotetrasiloxane [(C₆H₅) ₂SiO] ₄.

The cyclosiloxanes used according to the invention are colorless Room temperature preferably solid connections with a number of more advantageous application properties. They are easy to dose, so that Processability is made considerably easier. They are also industrial hygiene harmless, temperature resistant and form in the melt processing of High performance thermoplastics no toxic decomposition products. Furthermore, they are anti-corrosive, since the processing of corrosive Polymer melts such as polyphenylene sulfide are a reduced attack with the Melt shows parts coming into contact.

When melting thermoplastics, they also act as Mold release agent. Furthermore, the cyclosiloxanes are defined as compounds in high purity available and inexpensive.

The use of the cyclosiloxanes used according to the invention can be according to known methods. The connections can for example the granules are tumbled or with the help of mixing equipment in the Polymer powder can be mixed.

The compounds used according to the invention are distinguished by a large one  Wide range of applications and are particularly useful as processing aids in such Suitable polymers for the suitability of silicone oils, e.g. B. with regard to Demolding properties has been proven. Such polymer classes are, for example Polyolefins, such as polypropylene and polyethylene, styrene homo- and copolymers for example polystyrene, acrylonitrile / butadiene / styrene copolymer, styrene / acrylonitrile Copolymer, also polyurethanes, polyamides, especially the fully aromatic Polymers (polyaramides), polyesters, especially the fully aromatic polymers (Polyarylates), epoxy resins and fluoropolymers.

The tools used are particularly suitable for processing high temperature resistant polyarylene ethers, e.g. B. polyphenylene oxide, which as Mixture with styrene is commercially available ("®Noryl", manufacturer: General Electric Plastics, Bergen Op Zoom, Holland), also the various available Polyarylene ether ketones, polyarylene ether sulfones, polyphenylene sulfides and polyarylates.

The mixture according to the invention can be conventional additives such as filling and Reinforcing materials, pigments, processing aids and the like a. added in quantities the properties obtained according to the method of the invention do not interfere.

The use of polymers provided with lubricants is very advantageous in the Food industry.

Furthermore, the use of the mixtures according to the invention for the production electronic components, such as microelectronic circuits suitable in the Polymers are embedded. This has a favorable effect that the Compounds used according to the invention have an anticorrosive effect and not cause ionic impurities. For example, cause Sodium ions which u. a. by using sodium stearate as a lubricant can be introduced, damage from microelectric Circuits.  

The parts and percentages given in the examples relate to the weight.

Examples Effectiveness of the lubricant

The effectiveness of lubricants for thermoplastics was checked by testing the Flow behavior of the thermoplastics, which contained the lubricants to be tested, in the so-called spiral test determined. In the sprial test, the fluidity of Thermoplastics with and without additives tested under defined conditions (see "Taschenbuch der Kunststoffadditive", publisher: R. Gächter and H. Müller, 1979, p. 264).

Octaphenylcyclotetrasiloxane (OPCS) was mixed in powder form in proportions of 0.1 to 2% by weight with the powdered thermoplastic PEEKK (MFI 400/5 = 15 g / 10 min) and this mixture was mixed on a twin screw kneader type LSM 30.34, manufacturer: Leistritz, Nuremberg, Federal Republic of Germany, plasticized and homogenized under the following conditions:
Cylinder temperature profile: 380 ° C to 400 ° C rising to the spray head
One-hole nozzle, water bath, granulator.
For comparison, a mixture with 0.5 wt .-% PTFE (melting point (DSC) 327 ° C, melt viscosity 10 ³ Pa · s, primary grain size 0.1-0.5 microns) was prepared under the same conditions.

The thermoplastic granules to be tested with the various proportions of the octaphenylcyclotetrasiloxane were pressed into a spiral shape under the following conditions using an KM 90 / 340A injection molding machine, manufacturer: Krauss-Maffei, Munich, Federal Republic of Germany:
Screw diameter: 35 mm, L / D ratio: 20, melt temperature: 400 ° C,
Tool wall temperature: 200 ° C, spiral cross section: 8 × 2 mm ²
Spray pressure: variable between 1000-1400-1800 bar.

The comparison material was tested under the same conditions.  

Table 1 shows the spiral lengths obtained (in cm) that correspond to the cooled moldings were measured. The advantage of according to the invention OPCS compared to a blank sample and PTFE is clearly recognizable. It can also be seen that the effect of the amount of lubricant added is dependent.

Table 1

The test series shows that the flow behavior of the thermoplastic with increasing proportions of the lubricant used according to the invention improved compared to a blank sample and to the mixture with PTFE.

In Fig. 1 the results are shown as curves.

The mechanical properties of standard test bars are determined by the addition generally not of the cyclosiloxanes used according to the invention changed.

The results are summarized in Table 2.  

Table 2

Mechanical properties of PEEKK-OPCS mixtures

Claims (6)

1. Mixture of thermoplastic polymers and organosilicon compounds, characterized in that at least one cyclic silicone compound of the formula (I) wherein R ¹ and R ² independently of one another denote the same or different alkyl or aryl groups and n is an integer from 3 to 10, in amounts of 0.01 to 5% by weight, based on the polymer used, is present. 2. Mixture according to claim 1, characterized in that R ¹ and R ^{2 are} methyl or phenyl groups and n is 3 or 4. 3. Mixture according to claim 1 or 2, characterized in that the cyclic organosilicon compound in an amount of 0.1 to 1% by weight is included. 4. Mixture according to one or more of claims 1 to 3, characterized characterized in that as the cyclic organosilicon compound octaphenyl-cyclo tetra-siloxane is used. 5. Mixture according to one or more of claims 1 to 4, characterized characterized in that fillers, reinforcing materials and / or pigments as further Usual additives are included. 6. Use of the mixtures according to one or more of claims 1 to 5 for the production of electronic components and in the food industry.