EP0000733B1 - Blends of polyarylsulfones and polycarbonates and their application during the manufacture of extruded films - Google Patents

Description

The present invention relates to polyarylsulfone-polycarbonate mixtures of 90% by weight to 60% by weight of linear polyarylsulfone and 10% by weight to 40% by weight of homopolycarbonate made of bis-2- (4-hydroxyphenyl) propane ( Bisphenul A) or copolycarbonate from at least 30 mol% bisphenol A and up to 70 mol% from other diphenols, the polycarbonate component having an Mw (weight average molecular weight) greater than 60,000.

The mixing ratio is preferably between 85% by weight to 70% by weight of polyarysulfone and between 15% by weight and 30% by weight of polycarbonate.

Mixtures of polyaryl ether sulfones and polycarbonates have already been described (see DT-OS 1 719 244 and US Pat. No. 3,365,517); likewise their use for the production of films (page 21 of DT-OS 1 719 244).

These mixtures are intended, on the one hand, to eliminate the undesirable embrittlement of the polyaryl ether sulfones and, on the other hand, to make the polycarbonates susceptible to stress cracking with solvents (page 2 of the DT-OS).

Such mixtures can be used for the production of cast films (Examples 8 and 9 of the DT-OS and 14 and 16 of US-PS). In the literature references mentioned, the polycarbonates which are usually suitable for injection molding and extrusion are given as polycarbonates, and their M w is, for example, about 35,000 (example 2 of the DT-OS). However, films made from such mixtures show a strong tendency to stress corrosion cracking.

If the polycarbonate component with an Mw of 35,000 described in DT-OS 17 19 244 or US Pat. No. 3,365,517 is replaced by a high molecular weight polycarbonate that cannot be extruded without molecular weight reduction and cast films made from such mixtures, these products also show a strong tendency Stress corrosion cracking and poor mechanical property values.

In contrast, it was surprising that the polyarylsulfone-polycarbonate mixtures according to the invention provide extrusion films with an excellent property profile, even though they contain a polycarbonate component which cannot be extruded without molecular weight degradation and although the mixtures are not suitable for the production of cast films.

Polyarylsulfones suitable according to the invention are basically all known linear aromatic polysulfones and polyether sulfones with Mw (weight average molecular weight measured, for example, by means of light scattering) between about 15,000 and about 55,000, preferably between about 20,000 and 40,000.

Such polyarylsulfones are described, for example, in the following references: in the previously mentioned DT-OS 1,719,244 and US Pat. No. 3,365,517.

worin Ar' einen Biphenylen- oder Oxibiphenylen-Rest, n O oder 1, Z einen p-Phenylenrest, m-Phenylenrest oder zweibindigen Rest der folgenden Formel (11)

entspricht, worin R einen zweiwertigen C₁―C₁₂-Alkylen- bzw. Alkyliden-Rest, C₅―C₁₂-Cycloalkylen- bzw. Cycloalkylidenrest, C₇―C₁₂-Aralkylen- bzw. Aralkyliden-Rest oder C₈―C₁₂-Arylen-bisalkyliden-Rest oder die Gruppierung -0-, -S-, -SO-, ―SO₂―, -CO- oder eine einfache Bindung bedeutet.Preferred polyarylsulfones are those of the following structural units of the formula (I) obtainable from bisphenols and dihalogenarylsulfones

wherein Ar 'is a biphenylene or oxibiphenylene radical, n O or 1, Z is a p-phenylene radical, m-phenylene radical or divalent radical of the following formula (11)

corresponds in which R is a divalent C ₁ -C ₁₂ alkylene or alkylidene radical, C ₅ C ₁₂ cycloalkylene or cycloalkylidene radical, C ₇ C ₁₂ aralkylene or aralkylidene radical or C ₈ C ₁₂ arylene bisalkylidene radical or the grouping -0-, -S-, -SO-, ―SO ₂ -, -CO- or a simple bond.

The weight average molecular weights of the polycarbonates suitable according to the invention should be above 60,000, preferably between 65,000 and 120,000 and in particular between 75,000 and 95,000. (Determined from the intrinsic viscosity, measured in CH ₂ Cl ₂ solution).

Aromatic polycarbonates for the purposes of the invention are homopolycarbonates of bis-2- (4-hydroxyphenyl) propane (bisphenol-A) and copolycarbonates of at least 30 mol%, preferably at least 60 mol% and in particular at least 80 mol% of bisphenol A. and up to 70 mol%, preferably up to 40 mol% and in particular up to 20 mol% from other diphenols. (The molar percentages each refer to the total molar amount of condensed diphenols).

As other diphenols, bis- (hydroxyaryl) -C ₁ -C _s -alkanes other than bisphenol A and bis- (hydroxyaryl) -C ₅ ―C ₆ -cycloalkanes are suitable, in particular bis- (4-hydroxyphenyl) -C ₁ ―C _8- alkanes and bis- (4-hydroxyphenyl) -C ₅ ―C ₆ -cycloalkanes.

• 2,4-Bis-(4-hydroxyphenyl)-butan,
• 1,1-Bis-(4-hydroxyphenyl)-cyclohexan,
• 2,2-Bis-(3-methyl-4-hydroxyphenyl)-propan,
• Bis-(3,5-dimethyl-4-hydroxyphenyl)-methan,
• 2,2-Bis-(3,5-dimethyl-4-hydroxyphenyl)-propan,
• 2,4-Bis-(3,5-dimethyl-4-hydroxyphenyl)-2-methylbutan und
• 1,1-Bis-(3,5-dimethyl-4-hydroxyphenyl)-cyclohexan geeignet.

Examples of other diphenols are bis- (4-hydroxyphenyl) methane (bisphenol F),

• 2,4-bis (4-hydroxyphenyl) butane,
• 1,1-bis (4-hydroxyphenyl) cyclohexane,
• 2,2-bis (3-methyl-4-hydroxyphenyl) propane,
• Bis (3,5-dimethyl-4-hydroxyphenyl) methane,
• 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane,
• 2,4-bis (3,5-dimethyl-4-hydroxyphenyl) -2-methylbutane and
• 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) cyclohexane is suitable.

Copolycarbonates preferred according to the invention contain bisphenol A and 1,1-bis (4-hydroxyphenyl) cyclohexane (bisphenol Z).

• 1. Durch gemeinsames Aufschmelzen des Polycarbonats und des Polyarylsulfons unter gleichzeitiger oder nachfolgender inniger Vermischung der Schmelze und anschließender Extrusion der homogenisierten Schmelze in einer geeigneten Apparatur.
• 2. Durch Aufschmelzen des Polyarylsulfons in einer geeigneten Apparatur und Eindosierung des Polycarbonats in die Schmelze des Polyarylsulfons, Homogenisierung und anschließende Extrusion des Gemisches in einer geeigneten Apparatur.
• 3. Durch Mischen der Lösungen des Polycarbonats und des Polyarylsulfons, Ausdampfen des Lösungsmittels unter Aufschmelzen der Mischung und gleichzeitige Extrusion.
• 4. Durch Zumischen einer Lösung des Polycarbonats zur Schmelze des Polyarylsulfons, Ausdampfen des Lösungsmittels unter Aufschmelzen des Polycarbonats, Homogenisierung der Schmelze und anschließende Extrusion in einer geeigneten Apparatur.

The polyarylsulfone-polycarbonate mixtures according to the invention can be produced by the following four processes:

• 1. By melting the polycarbonate and the polyarylsulfone together with simultaneous or subsequent intimate mixing of the melt and subsequent extrusion of the homogenized melt in a suitable apparatus.
• 2. By melting the polyarylsulfone in a suitable apparatus and metering the polycarbonate into the melt of the polyarylsulfone, homogenizing and then extruding the mixture in a suitable apparatus.
• 3. By mixing the solutions of the polycarbonate and the polyarylsulfone, evaporation of the solvent with melting of the mixture and simultaneous extrusion.
• 4. By adding a solution of the polycarbonate to the melt of the polyarylsulfone, evaporating the solvent while melting the polycarbonate, homogenizing the melt and then extruding it in a suitable apparatus.

Preferred mixing processes are processes 2 to 4, and mixing process 4 is particularly preferred.

Suitable apparatuses for the production of the polycarbonate mixtures according to the invention are rollers, kneading and screw machines. Preferred apparatus are screw machines, in particular twin-screw machines.

The production of the extrusion films from the blends according to the invention can be carried out in a known manner e.g. take place on normal, state-of-the-art, catchy three-zone screws, the deformation into foils being able to take place both via wide-slot nozzles to form foils, and also via blown film heads to blown foils.

The extrusion films according to the invention have a particularly advantageous property profile, which makes them suitable, for example, for use in the electrical sector.

Among other things, the extrusion films according to the invention have a high mechanical strength, a high resistance to stress corrosion cracking in the heat and to organic liquids, a high heat resistance and long-term heat resistance. In particular, they are characterized by their resistance to unsaturated polyester resin solutions.

The additives or fillers known in polycarbonate and polysulfone chemistry can also be added to the mixtures according to the invention.

In this context, mention may be made, for example, of dyes, pigments, mold release agents, stabilizers against moisture, heat and UV exposure, lubricants, fillers such as gias powder, quartz products, graphite, molybdenum sulfide, metal powder, powders of high-melting plastics, e.g. Polytetrafluoroethylene powder, natural fibers such as cotton, sisal and asbestos, furthermore glass fibers of various kinds, metal threads as well as fibers which are stable and do not noticeably damage the polycarbonates while they are in the melt of the polycarbonates.

Example 1:

80% by weight of a linear polyarylsulfone, produced by condensation of 4,4'-dichlorodiphenylsulfone and bis-2- (4-hydroxyphenyl) propane with an Mw of 20,000 and 20% by weight of a polycarbonate based on bisphenol A with a M _w of 95,000 are melted together in a 2-shaft screw, the cylinder temperatures being 340 ° C. The melt is pressed out as a strand. The strand is cooled and granulated. The granules obtained are melted on a single-shaft screw with a degassing zone, and the melt is pressed out via a slot die and drawn off using a chill-roll system to about 40 μm thick films. The property values obtained are listed in the table below.

Example 2:

Production of foils acc. Example 1, but using 70 wt .-% of a polyarylsulfone acc. Example 1 and 30% by weight of a bisphenol A polycarbonate, the M _{w of which is} 75,000. The property values of the film obtained are listed in the table below.

Example 3: (comparative example)

The polymers acc. Example 1 were dissolved together in methylene chloride, the concentration of the polymer mixture in methylene chloride being 17% by weight. After filtering and degassing, the solution was cast in a known manner on drum casting machines to give films about 40 μm thick. The film obtained was subsequently dried at 120 ° C. to remove the residual solvent content. The properties of the film are listed in the table below.

Example 4: (comparative example)

From 80 wt .-% of a polysulfone acc. Example 1 and 20 wt .-% of a bisphenol A polycarbonate, whose M _{w is} 30,000, a granulate according to Example 1 produced and processed on a single-screw screw with a blow head to about 60 microns thick films. The cylinder temperatures were 280 ° C in the feed zone and 310 ° C in the following zones. The nozzle temperature was also set to 310 ° C. The nozzle gap was 0.8 mm. The tube was expanded in a ratio of 1: 4. The take-off speed of the film winder was set so that the desired film thickness of 60 μm was obtained at the selected screw speeds. The property values of the film obtained are listed in the attached table.

Claims (6)

1. Polyaryi-sulphone/polycarbonate mixtures comprising 90% by weight to 60% by weight of a linear polyaryl-sulphone and 10% by weight to 40% by weight of a homopolycarbonate of bis-2-(4-hydroxyphenyl)-propane (bisphenol A) or a copolycarbonate of at least 30 mol % of bisphenol A and up to 70 mol % of other diphenols, the polycarbonate component having a Mw (weight-average molecular weight) greater than 60,000.

2. Mixtures according to claim 1, characterised in that the Mw of the polycarbonate component is between 65,000 and 120,000.

3. Mixtures according to claim 1, characterised in that the Mw of the polycarbonate component is between 75,000 and 95,000.

4. Mixtures according to claims 1 to 3, characterised in that they contain 85% by weight to 70% by weight of a linear polyaryl-sulphone and 15% by weight to 30% by weight of a polycarbonate.

5. The use of the mixtures according to claims 1 to 4 for producing extruded films.

6. Extruded films obtainable from the mixtures of claims 1 to 4.

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