DE1520107A1 - Process for the production of oxymethylene polymers - Google Patents

Description

PATENTANWÄLTE DR.-IN G. H. FINCKE DIPL.-ING. H. BOHR DIPL.-ING. S. STAEGER

'Long distance call! »26 6060

8 MÜNCHEN S, Müllerstrafle 31

1963

j läppe 19050 - Dr,]? ./ P ΙΟΙ Oaae JP. 15777/16100

description

to the patent application of

tfirma IMPERIAL OHEMIGAL INDUSTRIES LIMITED, London SWl,

concerning

"Process for the production of oxymethylene polymers"

Priorities: No. 44 819/61 - December 14, 1961 No. 20 173/62 - 25 * May 1982 and 10o November 1962

Great Britain

The invention relates to a method for producing Oxymethylene polymers "

Oxymethylene polymers, often also referred to as polyoxymethylenes, contain units of the structure g - in their molecule and can _, according to British patents 748 856 and 877 820, by polymerizing formaldehyde

909828/1477

- / 2

or its cyclic trimer trioxane. Polyoxymethylenes produced by customary homopolymerization processes generally contain terminal oxymethylene hydroxyl groups (-OCH ₂ OH). These polymers are built up when heated, even if this is done at quite moderate temperatures. To avoid these undesirable properties, it has been proposed to react the hydroxyl end groups with compounds which replace the relatively unstable hydroxyl group with a more stable end group, for example an acetate, ether or urethane group.

jis was found according to the invention that one valuable high molecular weight Oxymethylene polymers with good stability by polymerizing an oycljechen oligomer of formaldehyde in the presence can produce certain aromatic compounds.

According to the invention, a copolymer of a cyclic Ologomer of formaldehyde, preferably trioxane, and an aromatic compound of the general formula

909828/1477

BATH ORIGINAL

■ / 3

provided, in which X represents a methylene or substituted i / Iethylengruppe, an oxygen atom, a sulfur atom or a sulfone group and R ₁ and R _n are hydrogen atoms and / or monovalent hydrocarbon radicals ₀

Of the cyclic Ollgoraeren des -Formaldehydes trioxane is due to Tetraoxyethylene is preferred for its ready availability an example of another such cyclic oligomer »

Examples of those used as comonomers according to the invention aromatic compounds are indene, coumarone, thionaphthene, Thionaphthene dioxide and its substituted by hydrocarbon radicals Derivatives,

Very suitable comonomers are indene and coumarone because of their easy accessibility, their solubility in trioxane and the considerable stability of the resulting copolymers with trioxanes. Accordingly, the invention provides a copolymer from a cyclic oligomer of formaldehyde, preferably trioxane, with indene or oumarone.

ORIGINAL 909828 / H77 ~ * ^K

For the manufacture of products with good physical properties the copolymers should preferably have more than 50 mol, preferably at least 80 mol of oxymethylene units contain. Mixed polymers with at least 90 MoIJ * of such Units are looked "hard and" more suitable for molding. Preferably the copolymer contains at least 0.1 mol # and preferably in particular at least · 0.5 mol # of units other than Oxymethylene units, since the presence of smaller amounts of these units generally does not have an adequate effect on the thermal stability of the copolymers exerts. Copolymers with 1.5 to 5 MoI ^ such units have a useful stability and strength and are good molding compounds.

Copolymers with a higher content of other units than Oxymethylene units, especially those with more than about 20A in such units, are less solid and dimensionally stable and they have a lower softening point. These products are suitable as plasticizers, lubricants and viscosity modifiers.

"AD ORIGINAL

8Q9828 / U77 ~ ^{/ 5}

Particularly valuable polymers contain at least 90 oxymethylene units and they have a molecular weight of at least 15,000, preferably 20,000 or more. A molecular weight of 20,000 corresponds approximately to an inherent viscosity of I ₉ O, measured at 60 * 0 in an above solution of ρ-chlorophenol with a content of 2 £ α-pinene. |

Brfindungsgeaäee will continue to be a method of manufacture of high molecular weight oxymethylene polymers sur provided, in which an oligomer of formaldehyde with an oyolisohes an aromatic compound of the general formula

- ^R i

in which X denotes a methylene group or methylene group substituted in ·, an oxygen atom, a sulfur atom or a sulfonic group, and R ₁ and R _{9 are} hydrogen atoms and / or monovalent

Hydrogen residues are, in the presence of an electrophilic catalyst, rather than a very small amount of water is polymerized.

The poly produced by the process according to the invention BATH ORIGINAL

- / 6 909828 / U77

_ 6 - "
Merisates can be tough, feet and extraordinarily heat-stable.

The polymerization can be carried out in Maaee or in solution will*

The bloc polymerization is normally carried out at a temperature at which the polymerizable material is in molten or substantially molten form. For the production of high molecular weight polymers, e.g. polymers with an iron molecular weight of more than 15000 ₉ , the polymerization temperature should not be too high so that no significant depolymerization occurs. On the other hand, one works preferably at a temperature at which the aromatic compound Trioxane is soluble.

The polymerization is preferably carried out at temperatures from about 0 to about 100.degree., In particular from 90 to 90.degree. If the polymerization is carried out in a misoher, it is often advisable to work at temperatures as low as UO ⁹ O or higher. If you are at temperatures above about 115 * 0, the boiling point

BAD ORIGINAL _y /. 909828 / U77

dee Trioxane, who wants to work, has to do the polymerization at überatiao spherical pressure

In the case of polyraeration in solution, an aromatic compound ale Ooraonomer is preferably used, which is soluble in the mixture of trioxane and solvent. * Suitable solvents are, for example Kohlenwaaeerstoffe such as hexane, heptane, Qyolo «hexane, Beneol, toluene and xylene" and ohlorierte hydrocarbons such as Mehtylenohlorid, chloroform or carbon tetrachloride. The polymerization is preferably carried out at a sufficiently high temperature to avoid recrystallization of the polymerizable compounds. However, the working temperature should not be above the boiling point of the solution at the working pressure.

The polymerization can take place satisfactorily in the presence of a very small amount of water, as occurs as impurities in the oligomer or the aromatic compound.To achieve good yields of high molecular weight material, practical

909828 / U77 ~ ^{/ 8}

table removes all traces of water from the polymerization medium. The medium preferably contains less than 0.05 ^, in particular less than O ₉ O? Wt .- ^ water.

Anyone can electrophilic for the polymerization according to the invention Catalyst can be used. Examples are Lewis acids, Friedel-Crafts catalysts, elemental iodine, Perchloric acid and acetyl peroxide. Of these are Lewisaurs, the halides are preferred. In particular, supplies Boron trifluoride very good results. Bas boron trifluoride can be used as can be used solohes or in the form of one of its complexes. Examples of boron trifluoride complexes are sojphe with water, with organic compounds containing an oxygen or sulfur atom that can act as a donor atom, e.g. alcohols,. Ethers, acids and their sulfur analogues, with organic compounds with a trivalent nitrogen or phosphorus atom, e.g. amines and phosphines, and fluoborate complexes, such as those with Diazonium compounds. The amount of catalyst used is generally 0.0001 to 0.1 part by weight of active ingredient ie 100 parts by weight of monomeric material, if one takes shapes and

BATH ORIGINAL 909828 / U77 " ^{/ 9}

Union processes produce suitable high molecular weight products wiU.

Since «molecular weight of the copolymers prepared according to the invention can be controlled by adding chain transfer agents to the polymerization medium. Suitable chain ^ Carriers are chlorinated «hydrocarbons, alkyl acetates and acetals The polymerization is preferably carried out with clay oxygen

The polymerization may be carried out in bulk or in the presence of only very small amounts of solvents, since then there is no need for costly solvent extraction and recovery. *

An embodiment according to the invention includes the aromatic Compounds and the trioxane first carefully dried and then in a predried reactor, see B * a Steel bomb, given. The reaction vessel can be filled with nitrogen be rinsed. The catalyst is then used alone or in the form of a solution in an inert organic solvent.

BATH ORIGINAL

909828 / U77 ~ ^{/ 10}

«» Given · The reactor is closed, and at about 65 * C heated, whereupon the polymerization is allowed to proceed · After the required time, the polymerization is terminated · The reactor contains the polymers, the Katalytatorrtlekstands and possibly unreacted trioxane and aromatic compound

In the above-mentioned production of high molecular weight polymers, the polymerization temperature is generally below the softening point of the polymers · Since the resulting polymers are usually insoluble in the mixture of monomers are »falls the product of a blookpolymerization im generally in a crumbly form · For good mixing and thus to promote a strong growth of the polymer chains and cur formation of a readily processable powder after completion Polymerization, it is prevented on the Polymerisatlonsmisohung to exert shear forces during the blook polymerization. Such forces can be exerted by suitable means, such as vigorous stirring or moving, be exercised «J> he polymerization can s, Bo in a container that can be rotated around a horizontal axis,

BAD ^ WlUirW * »»

909828 / U77

and the freely rolling balls, rods and the like. Contains, according to the British patent specification Mr. 749 086. Very good results are obtained when the polymerization ingredients be introduced into a continuously working mixer, which has a screw with an interrupted thread in a cylindrical body whose inner surface | before rows of protruding teeth. This snail is designed to both rotate and reciprocate so that the teeth on the wall of the aylindriachen Body run through the interruptions in the Sohneoken thread. In this case the polymerization mass moves like a screw with alternating forward and backward movement against the outlet. The use of this mixer also has the gate part that you can work continuously. Am suitable Apparatus is in British Patent Specification No. 6,626,067 described.

In this procedure, the aromatic compound and the trioxane are first carefully dried and then together with the catalyst in the pre-dried mixer, the

903828 / U77

BAD ORfGiNAt

-Λ2

is heated to the desired temperature. The polymerization took place in the mixer, which can optionally be kept under pressure, and the polymer is from the other end of the Mixer removed in the form of a slurry or a powder.

The material obtained contains the polymer product, catalyst residues and optionally unreacted trioxane and unreacted aromatic compound. The polymeric product consists of the copolymer of the trioxane and the aromatic compound and, if appropriate, polyoxymethylene by-products from the homopolymerization of the trioxane. The catalyst residues are preferably removed as soon as possible after the polymerization, as they also prevent the decomposition of the poly. more product can accelerate. The catalyst residues can be removed in a simple manner using vials of the reaction product with an aqueous, preferably an aqueous-alkaline washing solution. The mixture can be washed, for example, with a dilute ammoniacal solution or sodium hydroxide solution. It is well known that solvents can also be used for

EAO ORIGINAL

909828 / U77 ~ ^{/ l3}

removal of catalyst residues can be used. During the ab » Separation of the catalysts can also affect the polymer further kind of stabilized below.

The unreacted trioxane and the aromatic compound can be separated from the copolymer by suitable means, such as % filtration or solvent extraction. As trioxane iat soluble in most common solvents, it can for a Löaungemittelertraktionaverfahren, z _o B "DC" seitlg be removed with the removal of the catalyst. The aromatic compound can also be separated by solvent extraction.

The presence of polyoxyethylene by-products can increase have a detrimental effect on the stability of the material. This Disadvantage can be remedied either by selective destruction or by stabilizing these polyoxymethylene groups will.

The copolymers produced according to the invention contain

both oxymethylene groups derived from trioxane as

BAD ORlG, _NAi>

909828 / U77 - / U

auoh divalent organic residues that bioh derive from the aromatic compound. The misoh polymer chains can therefore end with groups of the structure -0-QH ₂ -OH or with other groups which are derived from the aromatic compound.

If a molten polymer chain bonds with an -OCH ₂ -OO - group, which can easily be split off by heating or by treatment with a base, the end of the chain can have the general formula

-PO (OH ₂ O) _n H

in which η is a whole number and P is the divalent organic ■ oh · remainder which is derived from τοη from the aromatic compound and which is closest to the end of the polymer chain. If the polymer chain is subjected to thermal or alkaline degradation, the -O-CH ₂ -OH group is split off and the immediately following oxymethylene group (if one is present) receives a hydrogen atom and becomes an -O-CH ₂ -OH- Group converted to "Dl" chain now has the general formula

The next group -0-CB ₂ -OH-GrUPPe is now attacked and

BATHROOM QRi

909828/1477 ^{/ 15}

the degradation of the chain continues until it reaches the -P ~ O group iato Oa the P-OH group is relatively more resistant to cleavage mining will normally stop here. The copolymer can therefore either be stabilized by subjecting it to such degradation or by group stabilization. It can be seen that under single degradation conditions Any homopolyoxymethylene present is completely degraded if the reaction conditions are sufficiently energetic

If the polyoxymethylene oil by-product is a problem and the unstable Eliminate oxyethylene end groups from the copolymer this can be done in a simple manner by heating the mixture in an inert atmosphere, ζ .Be under nitrogen, to a

done temperature of about 16O ⁰ C or above, after removal of the catalyst residues "preferably carried out at not too high temperatures, otherwise also the copolymer can be degraded to an undesirable Ausmaas. The selective destruction of homopolyoxymethylene can also be prevented by adding a weak acid, such as formic acid or acetic acid, or a base, such as sodium hydroxide solution; Caustic soda will, however

909828 / U77 - / 16

not preferred because they cause undesirable degradation of the interpolymer cause and can convert the formaldehyde formed into zuoker-like substances «

The stabilization by removal of unstable constituents w parts or "groups can in an alkaline medium to separate dee polymerization catalyst are carried out. In this preferred process, the polymer is treated with a basic, preferably aromatic, solution at moderately elevated temperatures. Presumably, the local solution only works topoohemisoh (cf. · for example * Staudinger, "Die Hochmolekularen Organic sohenverbindungen", pages 231 and 252, 1952) c For an effective conversion, the polymer is preferably treated either in a finely divided state or in solution. The formation of a solution can be promoted by working at elevated temperature and increased pressure »The advantage of such a process is that the catalyst, unreacted trioxane and homopolyoxyniethylene by-products can be separated from the copolymer in one step» After the solution has cooled down the desired stable oxymethylene polymer precipitates from the

Solution and can be separated.

BATH ORIGINAL

909828 / U77 .717

Instead of a strong ammoniacal solution, one can use similar conditions a solution of an amine, an eel or of a full hydroxide, such as sodium or potassium hydroxide, or a salsea of a strong base and weak acid such as sodium carbonate or sodium acetate, alone or in combination

use. The solvent can be water or preferably a Mixture of water and an alcohol that can be mixed with water, preferably methanol, a water-miscible ketone, such as Aoeton, or an ether · The presence of the organic compound facilitates the polymeric material in solution bring su

If one bevoreugt on the other hand, the end group * of the poly * oxymethylene-Jtebenproduktes and Oxymethylene! "! Groups of Misohpolymeristas tu stabilize can uasetssn the mixture with a suitable compound, which the terminal hydroxyl groups of the Homopolyoxymethylens and copolymers with other groups he set st, ss.B. Acetate, ether or urethane groups, which are relatively more stable. Bio end group stabilization can be achieved, for example, by converting the

BATH

909828 / U77 ~ ^{/ l8}

Misohpolymer composition with a carboxylic acid, a carboxylic acid ester, carbonic acid anhydride, alcohol, aoetal, Ieooyanat, ortho ester, ketal, ortho carbonate, ketone, a ketene-ketone conversion product, an ether or its substituted derivatives, an epoxy such as ethylene oxide or propylene oxide, a Olefin such as butadiene or styrene, an alkyl halide such as tert-butyl chloride, or a vinyl monomer such as acrylonitrile or acrolein, as a precautionary measure solution with a carboxylic acid anhydride, such as acetic acid anhydride carried out·

The Misohpolymer can continue to prevent degradation by adding a suitable stabilizer for the polyoxymethylene.Suitable stabilizers are e.g. hydrazines, amines, Amidines, amides, polyamides, phenols, substituted phenols, polynuclear phenols, especially alkylene-biB-phenols, ureas, Thioureas, quinones and certain aromatic nitro compounds, or mixtures thereof. Stabilizers against the Effects of UV light, such as hydroxy-substituted beneophenones, can also be incorporated into the polymer. Farther

ORIGINAL BATHROOM, -

909828 / U77

the polymer can be filled with fillers, pigments, mold release agents, Lubricants, plasticizers and others compatible Polymers are mixed "

The copolymers left in the present invention are different from the products of the homopolymerization of trioxane. The purikt of the copolymers is lower than that of the crystalline Homopolymer, and the lowering of the melting point increases »With increasing content of (^ monomer units in the mixed polymer

Also the melting points of the copolymers are less sharp a ι that of Homopolymerietae and 3chmel "interval with increasing content ans Comottomereinheiten in the mixed polymer wider _E have the homopolymers of trioxanes eg," a melting point of 170 ° C ₉ while the copolymer of trioxane with about 13 , 5 öew · - ^ Indene has a melting range of 161 to 167 * 0 · (At the first temperature value the polymer is 50 $ and at the second temperature value it is completely melted) »

Because of the size of the Söhaelebereiohes the in accordance with the invention BATH ORIGINAL

909828 / U77 ~ ^{/ 2} °

Copolymers are sum deforming or other Processing in massive form required conditions not as critical as for the homopolymer. The copolymers can therefore be processed more easily and are of particular interest for film-forming compositions · The copolymers ) are therefore commercially more attractive as molding compounds than the homopolymers.

The rate of thermal degradation of the copolymers, in particular of the products stabilized in the catfish described, is much slower than that of the homopolymer. Z.Bο is the rate of weight loss of a Homopolyoxymethylene of trioxane at 222 ⁰ C for about 3 ^ / min, while the rate of weight loss of the copolymers prepared erflndungsgemäss which are a ammonlakalisohen Wasohbehandlung unterwor £ s, generally less than 0,2j £ / Min and down to 0.03 # / min or less. Because of the surprising stability of the copolymers at temperatures well above their melting point, they are used for the production of objects, ββΒο insulators in electrical

BAD ORiGiNAL .

909828 / U77 " ^{/ 21}

Switchgear, suitable that can be subjected to elevated temperatures during use.

The copolymers produced according to the invention with at least 90 mol .-! * Oxymethylene units are tough and dimensionally stable at or above room temperature, and because of their very small size The speed of thermal degradation is particularly valuable as molding compounds, SoB »in injection molding, compression molding and extrusion processes, and for melt spinning and casting of fibers and foils «The mouldable copolymers preferably have a melting range of around 150 * 0. The copolymers can can also be dissolved in a solvent and cast into foils or spun into fibers.

Suitable solvents are, for example. o- and p-chlorophenol, benzyl alcohol and α-naphthol. The copolymers can e.g. electrotechnical industry for the production of small gears, roller bearings, bushings, clamps and cams, in the Motor industry for the production of dust caps or caps for jacking nipples and bearings, such as track rod connections,

BATH ORIGINAL

- / 22

909828 / U77 '

Lamp covers, instrument housings, low-stressed operations, such as oil pump gears, tachometer gears and windshield washers, self-locking threaded rings and other small formations can be used. Leneinheiten the novel copolymer "with low levels of OxymeXfty- w have one reduced strength, hardness and nierdrigeren Krweiohungspunkt" However, they are so suitable as Weichmaoher, lubricants.

The invention is further elucidated by the following examples. purifies "parts mean parts by weight"

In each of the examples, the stability of the interpolymer "was determined by placing a weighed sample in an open ampoule with a narrow neck that bent at an angle of about 180 ° was «The ampoule is held for a certain time about 2/3 in the vapors of boiling salicylic acid methyl ester, then removed, cooled in bis water and weighed. This attempt is at regular time intervals within a period repeated by at least 20 if! slots. The stability of each sample is reflected in its resistance to degradation under the

sen conditions. _{bad mamu}

90 9828/1477 - / 23

- 23 Example 1

A mixture of 54.3 parts of pure dry trioxane and 4.7 parts of pure dry indene were kept at 90 ° C. in dry nitrogen. 1 part of an oily solution of boron trifluoride diethyl ether in diethyl ether was injected into the mixture. After an induction period of 5 minutes, the polymer settled - M organization ac a light brown solid mass was obtained. After a further 5 minutes, the reaction mixture was allowed to cool, and the solid polymer formed was ground in 200 parts of acetone and then washed with 100 parts of methanol _{or the like}

The powder obtained was refluxed for 4 hours with 100 parts of ammonia with a density of O ₉ OdO, 100 parts of methanol and 100 parts of water Hg abs. dried. 8 parts of an almost white product were obtained.

When heated to 222 * 0, the polymer quickly lost 13 # of its weight. After that, the rate of degradation was 0 ₁ oil $ / l & tn. Of the

BATH ORIGINAL

909828 / U77

-TO

Sohmels range of the polymer "measured with a melting point" microscope was 161 to 167 ⁰ O. Under the same conditions a homopolyoxymethylene had a melting point of 170 ° 0 "

Sohmelegesponnen could be at a temperature of about 165) to IBO ⁹ O strong threads of the mixed polymer. Sas copolymer could AUOH below a sow, flexible film be sohmelsgepresst at about 185 ⁰ O.

Example 2

The process of Example 1 was repeated using 31.3 ropes of trioxane, 12.1 parts of indene and 1.25 parts of an aqueous solution of boron trifluoride diethyl etherate in diethyl ether. The induction period was 6 minutes. 14 parts of a light brown copolymer were obtained, which rapidly lost 12 ^ of its weight on heating to 222 * 0. The copolymer then decomposed at a rate of 0.02 ^ / MIn ₀

The Sohmelabereioh of the polymer was 14? up to 155 * 0. From a sample of the polymer film could be a tough sohmelzgepresst at 175 ⁰ O under a pressure of 20 tons. Due to the ultra

BATH ORIGINAL

909828 / U77

red absorption spectrum of this film showed a content of about 2 M0I - / & indene units

Example 3

37.2 parts of trioxane purified by distillation over oil hydride and 4.39 parts of coumarone purified in the same way were polymerized at 78 ° by adding 0.008 part of boron trifluoride diethyl etherate in 0.71 of diethyl ether. When the catalyst was added, the Ifasee turned yellow and after 30 minutes the Hasse was solid. The hat was cooled, ground and extracted with 200 parts of methanol. Then the mass was of density 0 ₉₈₈₀ boiled for 4 times with 40 parts of methanol, 50 parts water and 4.4 parts of ammonia under RUokflues · to obtain 9.7 parts of a welssen powder having a rate of weight loss of a β at 222 * 0 ( after an initial rapid weight loss of 12.5 / & due to incomplete ammonia treatment) of 0.1 during 200 minutes

From the copolymer could at 180 * 0 and a pressure of 20 tons of a 0.126 mm thick film could be formed.

909 828 / U77

BATH ORIGINAL

- / 25

Example 4

The polymerization of Example 3 was old 36.2 parts of trioxane and 7.12 ropes of coumarone (both dried in the same catfish) repeated. The polymerization was complete after 100 minutes, and the product was worked up according to Example 3. 5.8 ropes of fine white powder were obtained with a Rate of weight loss at 222 ° C of 0.15 # / tain within a period of 200 minutes.

Example 5

The polymerization of Example 3 was repeated at 75.degree. C. using 31.5 parts of trioxane, 3 _{tons of} O9 parts of coumarone and 0.006 parts of boron trifluoride diethyl ether in 0.71 parts of diethyl ether. The polymerization was complete in 5 minutes and the polymer yield after working up just about Example 3 was 15.1 parts of a white powder with a weight loss rate of 222 * 0 of 0.14 AA (In, measured over a period of 60 minutes.

The misoh polymer was at 190 * G under a pressure of 20 tons su a sähen undurohslohtigen white solid, molded, the could be bent without breaking

Claims : _{909828/1477 BÄD} original - / 27

Claims (1)

Claims Process for the production of copolymers by polymerization of trioxane with olyololic compounds by means of electrophilic catalysts, if necessary under shear conditions, daduroh characterized that as cyclic Oomono- j mere aromatis before compounds of the general formula , H ₁
^{1 line} is used in which X is an optionally substituted methylene radical, an oxygen atom, a sulfur atom or a sulfon group and R ₁ and R _{2 represent} hydrogen atoms and / or monovalent hydrocarbon radicals. 2. Mieohpolymer containing the product of the polymerization an oligomer of formaldehyde, especially trioxane, with an aromatic compound of the general formula "1 H ₂ in which X is a methylene or substituted methylene group 909828 / U77 BAD ORIGINAL New .y. ι _{Λ | γ} Is an oxygen atom, a sulfur atom or a sulfonic group, and R ₁ and R «are hydrogen atoms and / or monovalent hydrocarbon radicals 3 · misoh polymer according to claim 2, characterized in that φ the cyclic oligomer of formaldehyde trioxane 1st. 4. Mixed polymer. according to claim 2 or 3, characterized in that that the aromatic compound is indene or coumarone « 5 · mixed polymer according to claim 2 to 4, characterized in that no more than 99 »9 ^ of the units in the polymer chain are üxymethyleneinhelten. 6. Mixed polymer according to claim 3, characterized in that 90 to 99.5 pounds of the units in the polymer chain are oxymethylene units are" 7ο mixed polymer according to claim 4, characterized in that 95 to 98.5 $ of the units in the polymer chain are oxymethylene units. BATH ORIGINAL 909828 / U77 »/ 29 8 · Mixed polymer according to claims 2 to 7, characterized by a liquid viscosity of at least I ₁ O, measured at 60 · O in a 0.5% solution in p-chlorophenol with 2> α-pinene. 9. Uisohpolymer according to claim 2 bia 8, characterized in that the polymer chains are essentially free of terminal oxyethylene hydroxyl groups (-OdH ₂ OH) » 10 · mixed polymer according to claim 9 t characterized by a Speed of loss of life at 222 · 0 of less than 0.2 ^ / min for a first-order response. Mixed polymer according to Anepruoh 10, characterized by a Rate of weight loss at 222 * 0 of less than 0.03 A / ilin with a first-order reaction » 12 «mixed polymer, the units of which essentially consist of oxymethersene units (-GH ₂ O-) and units which are derived from an aromatic compound of the general formula ßAD ORIGINAL X 909828 / U77 derive in which X is a methylene or substituted methylene group, an oxygen atom, a sulfur atom or a sulfon group, and R ₁ and R _{2 are} hydrogen atoms and / or monovalent hydrocarbon radicals. ™ 13 · mixed polymer according to claim 12, characterized by that the units essentially contain oxymethylene and themselves Sound indene or oumeron are derived · binary units. 14 · Mlsohpolymer according to claim 12 or 13 «daduroh recognized *« It is worth it that at least £ 50 and at most 99.9 ^ of the units in the polymer chain olymethylene units are '15 · Misohpolymer NaOH Anspruoh 12 ms 14 »daduroh in that 90 to 99 are" 5 / <the Binheiten in the polymer chain of oxymethylene units. 16 · Misohpolyaer naoh Anspruoh 15, daduroh know rewarded, that 95 to 98.5 ^ of the units la of the polyether chain are oxymethylene units are· 909828 / U7 7- / 31 17. Mixed polymer according to claim 15 or 16, characterized by a low viscosity of at least 1.0, measured at 60 ° 0 in a 0.5 Agen solution In p-chlorophenol, contain 2 $ a-pinene » 18c mixed polymer according to claims 12 to 17, characterized in that that the polymer chain has practically no terminal oxy «* contain methylene hydroxyl groups 19 c. Mixed polymer according to claim 18, characterized by a weight loss rate β at 222 ⁰ O of less than 1.2 A / min in the case of a reaction of the first order ₀ 20o mixed polymer according to claim 19, characterized by a rate of weight loss at 222 ° 0 of 0.03, V ¹ Un * or less MTBiTAf (WMTE MHNO.H.I> INCK ", DIPi _-" NO.R "C #" MHUNO. t. «TAfM» BATH 909828 / U7 7