DE1645609A1 - Process for the production of waxy low molecular weight ethylene and ethylene copolymers - Google Patents

Description

VEB Leuna-Werke "Walter Ulbricht" Leuna, the '· κ

Patent department S / T * ^Jl

L.P, 621

Process for the production of waxy low molecular weight ethylene and ethylene copolymers

The invention relates to a process for preparing waxy low molecular weight, predominantly linear Äthylenpolymerisate and -mischpolymerisate high molecular weight by thermal degradation plastaxtiger, branched partly Äthylenpoly- m meriaate and -mischpolymerisate, wherein in a known manner, the starting materials prior to or in the degradation radical formers · and or or molecular weight regulators can be added.

It is known to polymerize ethylene into high molecular weight plastics. It is also known, from ethylene and vinyl acetate, Vinyl ethers and other alkenes η or dienes to produce plastics by copolymerization. The after these procedures The plastics obtained can be processed, for example, into films, pipes, cable insulation and injection-molded articles.

However, such high molecular weight plastic materials are not suitable as a polishing agent, rubber additives or paraffin fine ompounds for the manufacture of polishing compositions, leather care agents, corrosion A forward, self-shine emulsions, textile finishes, preservatives, inter alia, for this purpose is rather used predominantly waxy low molecular weight Äfchylenpolymerisate and ethylene-alkene copolymers.

It is known to produce such low molecular weight polymers by direct polymerization of ethylene or ethylene with other alkenes with the addition of chain transfer agents such as propane, butane and the like. Or with the addition of hydrogen.

When using chain carriers, branched ones are predominantly get soft polymers that have a high oil content. These products are used, for example, as a polishing agent and for the production of self-shine emulsions, polish lakes, Printing inks and others not suitable because it did not show any shine or

009821/1770

beget and only have an insufficient h-jrt ;: possess. Also through The addition of paraffins cannot overcome these disadvantages will.

With the addition of 10 to 15% by volume of A'asserstoi'l and at Temperaturren from 1 ^ 0 ° to 10 ° C and pressures from 300 to 500 at optionally using di-tert-butyl peroxide as a catalyst in the presence of benzene, waxy low molecular weight polyethylenes with a melting range of 106 ° to 109 ° C, a melt viscosity at 120 ° C of 400 to 200OcST are produced with a crystalline content of 60 to 65%, The products obtained in this way are well suited for the aforementioned purposes

By direct polymerization it is possible to use both. soft as well as medium-hard low molecular weight polymers to get. However, it is not possible in this way to produce v / axis-like products with a uniform molecular weight, as they do for example for the production of special polishing agents »temperature-resistant corrosion protection agents and coating waxes needed for the paper industry.

It is also known that waxy low molecular weight polyethylenes can be produced by thermal degradation of high molecular weight I olyäthylenes to manufacture.

For example, the degradation is carried out in vacuum or pressure vessels, by removing the starting product with the exclusion of Air and other oxidizing substances and under Hünren heated to a temperature above 290 ° C for a certain time.

It is also known to use high molecular weight Iolyäthylen at a Temperature between 100 ° G and 300 ° C and. a pressure between. and 420 at thermally degrade that nan the polyethylene passes through a pipe of small diameter.

This Verfahrenk where waxy low molecular weight polyethylenes obtained by thermal degradation, have the disadvantage that the degradation due to the poor thermal conductivity of the polyethylene used and the resulting wache- 'like products is either incomplete or that occur in certain places, overheating, which eiae Do not allow precise temperature control and thus the production of products with a uniform molecular structure.

It is known that these disadvantages can be avoided if the thermal degradation takes place in suitable heat-resistant materials Solvents performs. When using low-boiling

009821/1770 - / -

In solvents such as hexane, it is generally necessary to carry out the reaction under pressure in order to prevent volatilization of the solvent. Implementation under However, pressure brings an increased technical effort with rioi. As a particularly suitable solution for thermal degradation. ·: · Medium therefore higher-boiling solvents, such as liquid; " Paraffins, described. Your subsequent removal ready · -! however, due to the chemical similarity between the paraffins and the degradation products, considerable difficulties and is not possible without great effort.

The purpose of the invention is to provide the described Ilacirueile avoid.

It was therefore the task of creating a method with which it is possible, in a simple manner, to obtain waxy, low molecular weight oil predominantly linear ethylene polymers and copolymers due to thermal degradation of plastic-like high molecular weight, partly branched ethylene polymers and copolymers in one Atmosphere that is free of air and oxidizing substances, to manufacture.

According to the invention, this object is achieved in that the degradation of the polymers by a thermal treatment in a melt of already degraded ethylene polymers or copolymers at temperatures of 300 to 600 ° C, preferably 360 to 420 ° C, and residence times of 30 seconds up to 5 hours.

The thermal treatment is expediently carried out in one Stirred tank or in a combined with a flow tube Stirred tank,.

The starting products can be used before or during the Abi au Radical formers and / or molecular weight can be added in a manner known per se.

Investigations have shown that the thermal degradation of Temperature and residence time is dependent. If a constant temperature is maintained, however, the degradation curve is for a certain one Time a breakpoint so that it is possible for high molecular weight polymers to break down in a hot swathe perform. So z. B. a waxy low molecular weight polymer in a stirred tank with electrical heating

- / 0098 21/1770

BATH ORIGINAL

is provided, brought to the desired temperature The plastic-like, high-molecular-weight polymer to be broken down becomes granular or powdery in the intensely stirred melt entered and melted immediately. The rate of degradation can be regulated by the temperature or the residence time will. The harvester is expediently with a Treatment temperature maintained flow tube equipped through which the degraded v / axis-like, low molecular weight polymer is discharged with the specified dwell time.

The process can also be carried out in such a way that a mixture of high and low polymers at room-s temperature, which is melted and then brought to the desired temperature. It is also possible to the polymer to be degraded is introduced into the lower limb polymer, which is kept at a temperature below the degradation temperature, and then both components are transferred to the degradation device to heat. Finally, it is also possible to incorporate the high polymer in the molten state into the melt of the low polymer contribute, which is either heated to the degradation temperature or is brought to this temperature after the addition of the high polymer.

The process can be either batchwise or continuously be performed. The resulting from the dismantling Gaseous or volatile products can be sucked out of the stirred tank. On the basis of the present Invention given possibility of exact compliance with Temperature and residence time are simply end products obtained with a uniform molecular structure, so that a separation of products of undesirable molecular weight or a ** Eeir-cleaning is not required.

The process is particularly suitable for the production of Wax from inferior plastics that can no longer be used in plastics processing and which are then put to further use.

In the following examples the melting indices are according to the ASTM method, test no. D-1238-52 T, the viscosities determined by the coupler method.

In an electrically heated stirred tank with a

009821/1770

Capacity you 1 m ^ iser & sn 500 kg PölyS an Ssiuaelzbereich. from 95 Ms 102 ° E _s © let Hast ©

310 kp / cm ² , a viscosity of 100 cP "introduced at i ^ G ° G vm £ molecular weight of 2200 and heated to © la® of. 365 ° G · Nitrogen is used as a protective gas atmosphere» In the lower part of the stirred-tank " they are covered by the melted wax; © 5 π long heating coil with a width of 50 nuts through which the products from the armchair are passed through a shut-off device for the filling or Graauliesr-YQrMelrfeimg *

By means of a metering screw, koatinniex-liaSi 150 kg / Sta of polyethylene granulate with a melt index: from 2 _S 5 g / 10 min (ASTM method) into the Eührl ^ sssl entered Bmeeii die Bohr- ™

snake v / earth continuously fv 150 kg polyethylene? / aeha removed. The indwelling ze it of the product in line "bsfeägf 2 minutes. The resulting during the degradation volatiles are afegesaugt from the Eührkessel _Q

The polyethylene wax obtained is colorless and odorless and has the following characteristics:

Melting range 95 to 103 ° 0, hardness 315 kp / em ² ;, viscosity at 140 ° G - 108 cP.

Due to the high hardness and the excellent gloss, combined with a uniform quality, this polyethylene wax can mainly be used for polishing compounds and in the printing inks and textile industries, the like

In the stirred tank described in Example 1, 500 kg of polyethylene vinyl acetate wax with a Brw @ iGhuagpunkt of 110 ° C, and viscosity of 160 cP at 140 ° G «ad @ iae3i Mole kulargewä ^ ht of 3000 under StiokstoffatmospMss and at a temperature of 380 ° G The melt is heated per hour while stirring 175 teg viiiylaeetatmisehpolymeres with a Schmelaiad © 2s iron 3 g / 10 (ASfM-Iletiiode) and a finylacetatgaiialt T ©: a 28 set ate Duron the pipe coil are Syüsdiea 175 ^iy g I? © lywachsätljyleejKfii with a fsswoilseit "fu 115 & kor ^s®q;" nuie2 i uad withdrawn ld.ch 'naeli the Abküiilsa a?

808821/1770

164560S

These products are characterized by great clarity, ?:, eziöSLiti ± up to below -30 ° C and impermeability to water vapor from «You Xoaaen therefore- for the impregnation of cardboard and Papers must be used.

In the Hührkessei referred to in Example 1, 500 kg Polyäthyleswsohs with a melting range of 109 ° to 117 ° C, a hardness of 465 kp / cm _f «in viscosity of 145 eP at 140 ° 0 and a molecular weight of 250 ° and melted to one temperature heated by 350 ° C.

With stirring for a continuous hour, 100 kg of film ethyl alcohol had a salt index of 8.3 g / 10 ain (ASiEM method), into which 15 dicimyl peroxide was incorporated as an initiator _{at 1.50 ° 0 0 f 5} For an hour, 100 kg of Polyätfejienwaohs are continuously granulated through the pipe coil, sucked off after a period of 5 minutes and after cooling.

Ss is a colorless _# odor Freiss, hard and brittle polyethylene wax having a eriialten Eristallinität of 97%. The melting range is 113 ° to 117 ° 0, the viscosity is 140 np at 140 ° G, the polyethylene wax has a hardness of ¹ v55 kp This product is suitable for the production of high-quality self-gloss emulsions that have a permanent gloss and a high level of tread. and have wisck resistance,

Example 4

In the stirred kettle described in Example 1, 500 kg of polyethylene washes with a Schaelz range of 65 ° to 73 ° C and a viscosity of 84 cP at 140 ° 0 under a nitrogen atmosphere are melted and heated to a temperature of 410 ° 0. In this melt continuously 150 kg PoIyäthylengranulat s / 10 (ASTM method) eye having a melt index of 3 min set Zt ₃ Burch the Rohrsohlangewird -the same amount in a? Dwell time of 2 minutes removed, cooled and filled into barrels «

Bas so © rhaltesa Prodtüdj is farMc-s sis-hsllgelb and voa leieh * · klemxme ?? B ^ üüiia ^ is ^ höit. Bs s-si ^ 'i asiissü the same Gsis. ~ ^: Aq C & e, v ^ -s-göetzt *** ^ achs au: i uüd signst yourself prefer »

xü2? ami, Sin ^ from:.:. l = f ^ doh ^ sc-hutzwaahs scme as a lubricant

in the rubber and

Example 5

In the α Rührksss described under Example 1! 500 kg of ethylene-charcoal dmoiiosiä-mixed polyE.erisatTiasJss with a melting range of 95 Ms IuJ ⁰ 0, a hardness vs & 290 kg / cm, a viscosity of 100 el be 140 ° 0 and a ss & s molecular weight of 2100 as well as a content of 5 $ 6iapol ^ meri8i # rtem carbon monoxide under nitrogen atmosphere and heated to a temperature of 380 ° C. Then 80 kg of itli ^ len carbon dioxide & ^ poX ^ merisat with an average molecular weight of 2 ° OGO, which is used as a stabilizer 0 containing 7% Ditertiärtutyl-p-KresoI added · by di · coil werä ^ n continuously 30 kg / h färbloses Mischpolymerisatwachs with 3% 3% Kristaliinität, a hardness of 21 p kp / cm _s a viscosity of 115 cP at 140 ° G and a Sehnielzbesrsioli of 96 ° to 10 ^ ° C. This "after-type" is possible after treatment and is characterized by the filsbiXd'oag durali ^ ute glazing, water vapor impermeability and step resistance.

Example 6

In an electrically heated stirring vessel with a Faasungsve may η of 1 ar v.-earth 400 kg of polyethylene wax according to Example 1 at a temperature of 250 ° G melted. As the protective gas is argon · used kg stirring shortly ^{3.3> Λ,} H ^ chdruckpolyäthylengranulat min with a Sc-hr ^ lzindex of 2.3 g / 10 min. In the melt entered (ASTSHfetko & e) _t where the temperature is always above 230 ° G is held. The disfiguring viscous mixture is heated to 380 ° C. with stirring and kept at this temperature for 4 hours. During the breakdown, you can clearly notice dj = a beginning decrease in viscosity. The liquid wax is then drawn off, cooled and crushed within 3 hours.

The product obtained has a melting range of 90 ° to 97 ° C., a hardness of 24-0 kg / cm ² and a viscosity of 95 cP at 140 ° C. It is particularly known as Faraffincomponni iui-1

009821/1770 ^ "

Kabe! Wax suitable.

When producing several batches, it is advisable to use each Aiming only 350 g of wax and remaining in the stirred kettle Melt amount of more polyethylene *

Example 7

In the Eührkessel described in Example 6, a mixture of 400 kg of solid polyethylene wax according to Example 1 and 350 g of polyethylene with a melt index of 8 ^ 3/10 min (ASTM method) is placed at room temperature, under an argon atmosphere to a temperature of 385 ° C heated and kept at this temperature. After insertion of the melt, the teischung is stirred, degradation is complete after 3 ^1/2 hours of stirring, ·

The resulting wax is drawn off, cooled and crushed » It has the characteristics of the end product according to Example 6.

Example l β

The procedure is essentially as in Example 6. Instead of polyethylene granules, 250 ° G hot wax melt is added to already melted polyethylene at a temperature of 250 ° G by means of an extruder. Here, the time can the metering compared to Example 6 are reduced because the heat narrowness that would be required for melting the pellets, · is not needed here 4k The final products have the same characteristics as described in Example 6 on.

Example 9

In an electrically heated stirred tank with a capacity of 1 or 500 kg of polyethylene wax according to Example 1 submitted, melted and heated to a temperature of 365 C with stirring. At the bottom of the container there is an outside heatable tube of 5 m length and 50 mm clearance for the Wax print attached. According to Example 1, the melt will each Hour 150 kg of polyethylene granules with a melt index of S, 3 g / 10 min (ASTM method) added. With the heated to 365 ° C Every hour, 150 kg of polyethylene / aclis with a

009821/1770 ~ ⁷ ~

45609

-iiseit ναει 2 minutes © bg The WaoM obtained is the g the Eßdprodulrbe of BeisBi®ls 1 on ·

§ ■ §821 / 177

Claims (1)

Claims ι sup production of waxy jieden oil, predominantly linear ethylene polymers and mixed polymers, aurcli thermal degradation, plastic, high molecular weight ?! Sum ^{1 of} branched ethylene polymers and copolymers in an atmosphere which is free from air and oxidizing substances, shown by the fact that the degradation by thermal treatment in a melt of already decayed ethylene polymers or mixed polymers takes place at temperatures of 300 ° ^> is 600 ° 0, preferably 360 to 420 ° 0, and dwell times of 30 seconds to 5 hours are made * 29 ¥ experience according to claim 1, characterized in that the thermal treatment in a stirred tank or in a is carried out with a combined flow roller. 3. The method according to claim 1 and 2 _t, characterized in that radical formers and / or molecular weight regulators are added before or during the breakdown » CO8821 / 177G