DE1137167B - Process for the production of structures, such as threads or wires, from polycarbonates - Google Patents

Description

It is already known to use screw presses to process polycarbonates from the melt into rods, profiles and other large objects. However, these methods cannot readily be successfully applied to the manufacture of threads and wires with a small diameter. In these cases, only structures made of largely degraded polycarbonates are obtained. The threads are also opaque, not even and blistered. The degradation of the polycarbonates can be up to 50 ° / _0th In addition, there are constant spinning disorders.

It has now been found that structures, such as threads or wires, of polycarbonates then obtained when polycarbonates used with such a low water content such that during the heating of a sample at 300 ⁰ C for 1 minute, less than l ° / ₀ of the polycarbonate is degraded, and if the deformation is carried out from the melt with the aid of a melting screw at temperatures above the softening range of the polycarbonate used, but below 300 ^° C. with a residence time in the melting chamber of the screw of less than 40 seconds.

The threads and wires that can be produced according to the invention are transparent, uniform and white no bubbles. These good properties are due to the low deformation temperature and the short dwell time at this temperature and the good homogenization of the melt immediately before deformation traced back.

Such melting screws with a small volume are suitable for carrying out the process where only the nozzle is heated (autogenous screws). The heating of the polycarbonate is in these Screws, essentially, caused by the frictional heat. Such snails are z. B. in »plastics«, Vol. 46 (1956), pp. 18 to 20, described in more detail.

"Dwell time" is the period from the moment the polycarbonate becomes liquid until Understood passing the throttle gap of the melting screw.

The starting material is dried in the customary manner. About the water content Depressing to the extent necessary according to the invention is generally a drying of 5 to 10 hours at at least 115 ° C in a vacuum necessary. The chips should be as small as possible and not exceed a thickness of 3 mm.

The degradation of the polycarbonate on heating to 300 ^° C. for a period of 1 minute is determined by measuring the solution viscosity before and after the treatment. With a mining of 1 ° / o method of manufacture

of structures such as threads or wires,

made of polycarbonates

Applicant:

Paint factories Bayer Aktiengesellschaft,
Leverkusen

Dr. Alfred Reichle, Dr. BeIa from Falkai

and Dipl.-Ing. Heinrich Borger, Dormagen,

have been named as inventors

it is understood that the molecular weight determined by viscosity measurement decreased by 1% Has. The water content, which a degradation of

z. B. 1% caused is quite different for the different polycarbonates.

All linear high molecular weight thermoplastic polycarbonates are suitable for the process according to the invention suitable. These include, for example, the polycarbonates, which are made in a known manner Conversion of 4,4'-dioxydiphenyl-2,2-propane, 4,4'-dioxydiphenyl-l, l-ethane or 4,4'-dioxydiphenyl-1,1-butane can be obtained with phosgene.

example 1

To produce an endless wire with a diameter of 2 mm from a polycarbonate, which was produced in the usual way from 4,4'-dioxydiphenyl-2,2-propane and phosgene, 4 g per minute of absolutely anhydrous, dried polycarbonate chips (water content less than 0, 01%) ^w ith the aid of a highly accurate metering working of a screw extruder with 18 mm diameter screw fed. The screw rotates steadily at 70 revolutions per minute. The temperature in the screw is 28O ⁰ C. The melting content amounts to 2 cc so that the residence time is 36 seconds. A clear, translucent wire with a diameter of 2 mm emerges from the nozzle with a bore of 2 mm in diameter. It can be post-treated in a known manner. The degradation of the polycarbonate is below 1% that used

209 658/383

3 4

When heated to 300 ° C., the starting material shows less than 0.008% degradation of the polycarbonate for the period of 1 minute also one of the heating samples of less than 1%) and with the Degradation below 1% in the melting screw described in the invention

. -I ₉ a dosage of 7.5 g per minute with 85 screws-

Example l ₅ revolutions per minute at 256 ⁰ C screw temperature

Polycarbonate chips that are spun into threads by converting temperature through a nine-hole nozzle. 4,4'-Dioxydiphenyl-2,2-propane and phosgene are produced. The diameter of the nozzle openings is 0.25 mm. with a limiting viscosity number of The residence time of the material in molten [η] = 108 ccm / g (determined according to GV Schulz and the state in the melting chamber of the screw is in Horbach: Makromol. Chem., 29. p. 93 [1959]) io this spinning process 21 seconds, are carefully dried (water content less The threads are after exiting from the

than 0.08 ⁰ I ₀ , degradation of the polycarbonate at the heating nozzle cooled by blowing air and with a sample of less than 1%) and wound by means of a spinning device described at a speed of 420 m per minute, game 1 at a Do - After drawing in a ratio of ization of 9.2 g / minute at 125 screw revolutions 15 1: 3.75 above the freezing temperature of 130 ° C gene per minute and 288 ° C screw temperature by one obtains threads from nine individual threads with one a two-hole nozzle spun into threads. The through-single titer of 4.5 den. The strength is at 24% diameter of the nozzle openings is 0.3 mm. The elongation 2.7 g / den, both in the dry state and in the residence time of the material in the molten state, moist state. A measurement of the viscosity of the thread in the screw in this spinning process is 2 ° material shows that it is 16 seconds during the spinning process. less than 0.9% was degraded.

The threads are after exiting the nozzle.

cooled in a spinning shaft, with suitable example 5

Dissection prepared and at a speed polycarbonate chips, which by implementation of

wound separately from 520 m. It is obtained above 4,4'-dioxydiphenyl-2,2-butane with phosgene, the freezing temperature of 140 ° C and below that, with an intrinsic viscosity of [η] - 72 ccm / g, melting range of 220 to 230 ° C in One process is dried at 115 ° C. (water content is drawn at a ratio of 1: 4.03. The result is threads of 0.007%, degradation of the polycarbonate on heating. The strength is 3.4 g / denier for a sample of less than 1%) and with the elongation of 19% in the invention both in the dry and in 3 ° described melting screw with a dosage in the moist state. of 5.1 g per minute at 102 screw revolutions

A subsequent determination of the molecular weight per minute at a screw temperature of 256 ° C by a spun into wires by measuring the viscosity of the thread material after a three-hole nozzle. The one through above Method reveals that there is less than 0.5% diameter of the nozzle openings is 0.6 mm. the was dismantled. 35 Residence time of the material in the molten state

. , in the melting chamber of the screw is in this case

Example i spinning process 28 seconds.

Polycarbonate chips produced by the implementation of The threads are after exiting the nozzle

4,4'-Dioxydiphenyl-2,2-propane obtained with phosgene were passed through a cooling tank with an inert cooling liquid, with an intrinsic viscosity of [η] = 92 ccm / g 4 °, cooled and carefully dried at one rate (water content wound separately below 90 m per minute. After 0.005 ⁰ I ₀ , degradation of the polycarbonate during heating stretching at a temperature above the sample of less than 1%) and with a glass transition temperature of 130 ° C in Example 1 in a ratio described spinning device with a dosage of 1: 3.75 one obtains a wire of 0.15 mm of 8 g per minute with 105 screw revolutions per 45 diameter. The strength is 2.7 g / denier at a ^{screw temperature of 272 °} C. by an elongation of 17%> spun into threads in both a dry and a six-hole nozzle. The diameter also measured when wet. Such wires of the nozzle openings is 250 μ. The residence times are particularly suitable for the production of the material in the molten state in the filter cloth for the chemical industry. Snail amounts to 18 seconds. 50 ~. . ,, ".,. ,, .. ,,

After exiting the nozzle, the threads are Example 6 (comparative example)

Cooled by blowing air and using a polycarbonate chip made by reacting

Wound at a speed of 450 m per minute. 4,4'-Dioxydiphenyl-2,2-propane is obtained with phosgene. The stretching is carried out above the glass transition temperature, with a viscosity number of [η] = 108 ccm / g and below the melting range in a ratio of 55 and is only dried moderately (water content 0 , 2% of 1: 3.8. After stretching, degradation of the polycarbonate in the heating sample 5%), a rayon made of 6 individual threads with and with an autogenous melting screw with an individual denier of 6.6 denier is obtained. The strength is 3.2 g / the dosage of 9.2 g per minute and with 125 screws with an elongation of 21%. both dry and revolutions per minute at 288 ° C measured by a double damp. A viscosity measurement of the thread-hole nozzle spun into threads. The residence time of the material indicates that it was less than 0.5% degraded material in the molten state. this spinning process for 16 seconds. The ones from the

Example · 4 Melt exiting nozzle is full of bubbles, and it

is not possible from the material flawless

Polycarbonate chips that spin by putting 65 threads. A molecular weight determination of 4,4'-dioxydiphenyl-l, l-ethane with phosgene obtained by viscosity measurement shows that the material spun with an intrinsic viscosity of [η] -80 ccm / g has a molecular weight at 110 ° C carefully dried (water content which is more than 5% below the original

Molecular weight. Exceeding the inventive Maximum water content thus leads to unusable threads.

Example 7 (comparative example)

Polycarbonate chips obtained by reacting 4,4'-dioxydiphenyl-2,2-propane with phosgene, with a viscosity number of [η] = 108 ccm / g, are dried as in Example 2 (water content less than 0.08 ⁰ I ₀ , degradation of the polycarbonate in the heating sample 0.5%) and spun into threads through a single-hole nozzle with an autogenous melting screw at a dosage of 2.3 g per minute and at 125 screw revolutions per minute at 288 ° C.

The residence time of the material in the molten state is 63 seconds in this spinning process. The thread emerging from the nozzle is brownish and blistered and cannot be wound onto bobbins will. A molecular weight determination by viscosity measurement showed that the spun Material has a molecular weight which is 6% below the original molecular weight. the Exceeding the maximum residence time according to the invention also leads to unusable Threads.

Claims (1)

PATENT CLAIM: A process for the production of structures, such as threads or wires, of polycarbonates, characterized in that the polycarbonates used with such a low water content such that during the heating of a polycarbonate sample at 300 ⁰ C for 1 minute, less than 1 ° / o as the polycarbonate is degraded , and that the deformation is carried out from the melt with the aid of a melting screw at temperatures above the softening range of the polycarbonate and below 300 ^° C. with a residence time in the melting space of the screw of less than 40 seconds. © 209 658/383 9.