DE1906848A1 - Process for the preparation of oxymethylene copolymers - Google Patents

Description

DR.-ING. BY KREiSLER DR.-ING. SCHDNWALD DR.-ING. TH. MEYER DRFUES DIPL.-CHEM. ALEK VON KREISLER DIPL.-CHEM. CAROLA KELLER DR.-ING. KLOPSCH

COLOGNE 1, DEICHMANNHAUS

Cologne, 10 * 2.1969 Fu / Ax

Oelanese Corporation,

522 Fifth Avenue. New York, N.Y, 10056 (V.St.A.).

Process for the preparation of oxymethylene copolymers

The invention "relates to a method of manufacture of oxymethylene copolymers, in particular a process "in which QJrioxane and an Öomonoraeres in the presence of methylene chloride and a salt of arsenic or Phosphorus chlorides or fluorides are copolymerized.

It is "known that srioxane, which is an cyclic Irimeres von.Formaldehyd, can be homopolymerized in the presence of certain polymerization catalysts to form tough, thermally stable and pressable and sprayable oxymethylene polymers which _{contain recurring units of the formula -OH 2} O-.

These oxymethylene polymers are "medium-for example, by homo- or copolymerization of trioxane in the presence of certain fluoride catalysts, Z _0, in the presence of a catalyst, the coordination complexes of boron fluoride containing organic compounds, ·, prepared as in US Patent 2989506" described.

Other methods of making the oxymethylene polymers are described by Kern and co-workers in "Angewandte

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Chemie »73 (6), 177-186 (March 21, 1961), by Sittig in" Polyacetals: What Sou Should Know ¹¹ , Petroleum Refiner £ 11, 131-170 (November 1962) and in the ϋ _β S.Α »- Patent Specification 3,027,352.

Research continues, however, * to develop further methods of making oxymethylene polymers that have even higher molecular weights and can be used alone or in admixture with lower molecular weight polymers. The currently available commercially, trioxane derived oxymethylene normally have a molecular weight to about 130,000 (weight average).

It has now been found that oxymethylene copolymers which a much higher molecular weight of "for example up to about 500,000 ((rewichtsmitteX) -iiabea, produced can be.

The invention relates to a process for the production of oxymethylene oopol; pE © r © n ₂ in.sl3@SoH.dere. those with an average molecular weight of up to about 500,000 (weight average).

According to the invention are oxymetiiylenoopolymers by Positive phase polymerization of trioxane with an Oomonoä mers in the presence of methylene eliloride and one im Trioxane or a salt which is stable and soluble in the monomer made from arsenic or phosphorus chlorides or fluorides.

The crux of the invention is the use of methylene chloride together with the special ion pair or salt catalyst. It was found that by adding methylene chloride significantly increases the weight of the MoXekulai ' of the formed O ^ Tistliylencopolymaren im Compared to the molecular weight of the copolymer is obtained that w ■. I% · ΐ-ηη file polymerization reaction

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is carried out in the presence of the same Salzkätalysators without the addition of methylene chloride. Nooh more surprising is the! Eatsachej that "when using other, the Methylenohlo ± d similar materials, e.g. chlorobenzene, in place of methylene chloride in combination with the same Catalyst no improvement or no increase in molecular weight is achieved, rather it is The molecular weight of the copolymer is the same as or lower than when the salt catalyst is used alone. When nitrobenzene is used with the salt catalysts, the polymerization reaction is completely suppressed.

It has also been found that when a similar salt catalyst, for example a salt of antimony pentafluoride, is used with methylene chloride, the copolymer formed has essentially the same molecular weight as the copolymer formed when the salt of SbF ₅ is used alone.

Another important feature of the invention is the fact that the combination system is limited to the copolymerization of trioxane. Oxymethylene homopolymers obtained by polymerization von.T _r ioxan, have substantially the same molecular weight, whether the salt catalyst is used alone or in combination with methylene chloride.

The invention is described below in connection with the figures.

Figure 1 is a graphic representation of the catalyst concentration as a function of the molecular weight (number average) and illustrates the influence of methylene chloride in the homopolymerization of trioxane with p-chlorophenyldiazonium hexafluorophosphate as a catalyst.

Figure 2 is a similar graph showing the

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Influence of methylene chloride in the copolymerization of. Trioxane illustrated with ethylene oxide using the same catalyst

Fig. 3 is a graph of catalyst concentration / molecular weight (number average) and illustrates the influence of methylene chloride on the? Homopolymerization of trioxane with * p-chlorophenyldia2s © nii »a · = hexafluoroarsenate as a catalyst.

Figure 4 is a similar graphical representation di® des Influence of methylene chloride in the copolymerization of trioxane with ethylene chloride using d © s the same catalyst

Pig.5 is a graphic representation of the catalyst concentration as a function of the molecular weight (Number average) and illustrates the influence of methylene chloride in the copolymerization of trioxane with ethylene oxide using p-Ohlorphenyläiasoniiaii » hexafluoroantimonate as a catalyst.

According to the normal definition, oxymethylene copolymers have a structure consisting of repeating units, the general formula

R «
-0-CH ₂ - (C) _n -

R "

where η is an integer from O "to 4 and in 60 to 99.9 $ of the repeating units has dsn Wsrt 0, and where R ¹ and R" are inert substituents. _s doho substituents that do not contain any disruptive functional groups and do not dissolve any undesired reactions ₀ The oxymethylene copolymers preferably have a structure that consists of repeating oxymethylene and oxyethylene units, with 60 to 99.9 $, e.g. 60 to 70 to 99 , $ 9 of the repeating units oxymethylene units

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Those produced by the method according to the invention Oxymethylene copolymers can be more accurate than normal solid, essentially water-insoluble copolymers are defined, the repeating units of which essentially from units of the general formula

-0-0 (A) _n -

H Ho

■ consist, where R ^ and Hg for hydrogen, lower Alkyl groups and halogen-substituted lower alkyl groups and η is an integer from O to 4 and in 85 Ms 99.99έ of the recurring units has the value O. Each lower alkyl radical preferably contains 1 to 2 Carbon atoms

The above-described xymethylene copolymers can after the ^ "experience according to the invention by copolymerization of trioxane with at least one comonomer, in particular with a cyclic ether containing at least 2 adjacent carbon atoms will.

In general, for the preparation of the oxymethylers. Gopolymeric cyclic ethers of the general formula

R ₁ O (E ₅ ) _n

R ₂

used, in the R ^ and R ₂ for hydrogen, lower alkyl radicals and halogen-substituted lower Allqrlreste

with. stand and the radicals R, for methylene, Oxymetl ^ len, / lower

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Alkyl radicals and H substituted by haloalkyl and for oxymethylene radicals ated with lower alkyl and haloXkjX and η is a ß & sse IaMl O "to 3. Each lower AlkyXresi m§, HalQ preferably contains 1 Wb 2 carbon atoms © ο

A particularly preferred class of Gomonossoreia the cyclic ethers that make up the structure

CH ₂ -O
OH(

₂

have ₅ in dsr η an integer τοη 0 "to 2 is &

Xthylenoxyä and 1 ₁ 3 «MQS @ laa are preferably used as comonomers, but eigaeia sicsJä aaol cyclic ethers, z, B» 1 _s 4 ~ Bio3Ca, ii _s S methylenoxydj pentamethylene oxide, ip butylene oxide _s 1,3-3utyleno.i: yä safi 2 _e

Weitei-e spaaiiile
siM 1 _f 3 = -Bicx & n, 1,3,5-Er
rolaöton, Eq Qpentyl formal
hyd, Setraliyärofuran and

These and other commonly used oils can be copolymerized with trioxane to give the desired mers. Bar liier print "Copolyxaei'e ¹¹ also includes the ferpolj / seroia al polymers. For example, kömiea ti © Iqs cycliechen Xther with Polyepoxden Rad älal ilen for the production of! Derpolyaiöron ¥ © rw as in the US Patent AnmeMttrii If3 720 (20 «11 ₀ 1961) of the applicant" described *

d © - & w

In the oxymethylene copolymers according to the invention In addition, other eing-iirc ^ -g ^ ts M © aoM®reiaii®lt © n © athaltsn or be polymerized, e.g.® monomer units that

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from. Lactones, carbonates, cyclic or Säurehydraten äthylenisoh _s unsaturated compounds such as styrene, Diformaläther, vinyl acetate "or vinyl methyl Acroleir derived, as in the above-mentioned. Publication of core and hit workers described in "Angewandte Chemie" *

For the preparation of the oxymethylene copolymers according to the invention the monomer is usually in amounts of about 0.1 to 20 wt .- ^, preferably about 0.1 to 10 wt .- based on 4as the weight of the tricxan, used * at If several comonomers are used, the same weight restrictions apply

As already mentioned, is used as a catalyst for the purposes of the invention for the copolymerization of trioxane and des Gomonomeren an in. Trioxane or in the comonomer stable andlösliolieo salt of arsenic or phosphorus fluorides or chlorides. This catalyst is a stable and soluble salt in the trioxane or in the comonomer, that as the anion hexachloroarsenate, hexafluoroarsenate, hexachlorophosphate or contains hexafluorophosphate.

As used herein, pressure from "stable" or "stable" be · indicates that the ion-forming materials mentioned above do not readily decompose at room temperature, ie at 20 to 30 ⁰ C and at normal pressure. The ionic salt catalyst used must also in trioxane and / or in at least one of the comonomers using multiple Comonoiaerer be soluble _e Very common is the salt, both soluble in the trioxane and the comonomers. A soluble salt must be used in order to obtain a homogeneous liquid phase polymerization system containing trioxane, comonomer (s) _for the salt catalyst, and methylene chloride.

Any salts containing the anions mentioned above and the requirements in terms of stability and

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Solubility can be sufficient for the purposes of the invention be used. For example, alkyl or aryloxonium salts, aryldiazonium salts, alkyl or aryl carbonium salts, nitronium salts and hydrogen salts, doh. the acids themselves, e.g. HPFg, HPOIg, HAsFg and HAsCIg. Aryldiazonium salts, alkyl or aryloxonium salts or hydrocarbon salts which are those above contain mentioned anions, used

The oxonium salts used are preferably alkyloxonium salts, for example irimethyl, triethyl, tri-n-propyloxonium hexafluorophosphate or hexafluoroarsenate, methyl tetramethylene oxonium hexafluorophosphate, Ethyl-tetramethylene-oxonium-hexaohlorphosphat or hexafluoroarsenate, methyl or ethyl pentamethylene oxonium hexafluorophosphate the oxonium salts of dimethylpyron, coumarin and camphor .. -

The carbonium salts are preferably aryl or arylalkyl carbonium salts, e.g. triphenyloarbonium, methyldiphenylcarbonium and tri-p-methoxyphenyl carbonium salts are used.

Representative nitronium salts used for the purposes of the invention are nitronium hexafluorophosphate (NOpPFg) or nitronium hexafluoroarsenate (NO ₂ AsF ₆ ).

However, they are particularly preferred as salt catalysts the aryldiazonium salts, especially the aryldia & onium salts from AsFc, POl ^ and PF, -, again being the Salse. of AsFc and PFc are particularly preferred. As aryl component of the diazonium cation are any substituted aromatic compounds in question which contain at least one substituent group or a radical, e.g. an alkyl radical, an oxyalkyl radical and a haloalkyl radical, in which the alkyl radical preferably contains 1 to 5 carbon atoms, a cycloaliphatic radical, which is preferably

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Contains about 5 Ms 7 carbon atoms, halogen, preferably Cluor or chlorine, an alkyl sulfonate, a nitro group or a nitrogen, sulfur or oxygen substituent. Chlorine or nitro substituents are preferred used,

AIa Aryldiaaoniumsalze are p-Chlorophenyldiazoniumhexafluorophosphat or arsenate and p-nitrophenyldiazbnium hexafluorophosphate or arsenate preferred.

The salt catalyst is used in an amount of about 0.5 x 10 ^J to 2 χ 10 moles, preferably about 1 to 10 χ 1 χ 10 moles per mole! Drioxan. If necessary, larger amounts of catalyst can also be used.

The methylene chloride is used in an amount from about 0.1 to 20 wt. #, Preferably about 1 to 10 wt. #, E.g. about 5 wt .- #, based on the weight of the trioxane, used. Slightly higher amounts of methylene chloride can be used, but it has been found that the additional amount? beyond about 20% by weight no additional beneficial effect on the properties of the copolymers formed Has. Bring these excess amounts of methylene chloride even pose a recovery problem and represent an unnecessary additional expense.

The polymerization of trioxane with the comonomer in Presence of the salt catalyst and in the presence of methylene chloride is in the liquid phase in any übliohem, working in bulk and in the plüasigphase Polymerization systems continuous, semi-continuous or carried out in batches, for example, by the method that is the subject of the U.S.A. patent 3 254 053 is. In other words, the. The four components mentioned above form when used or when the initiation of the polymerization reaction a homogeneous Liquid phase, accordingly, at polymerization temperatures

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Doors in the range of about 55 "to 120 ⁰ O, preferably about 65 to 90 ⁰ O worked.

The polymerization time usually varies from about 0.5 to about 10 minutes, preferably γοη about 0.5 to 2 hours in a continuously operating system.

The greater part of the methyl chloride is usually evaporated with the progress of reaction and recovered with approximately formed further vaporous materials »The © formed as a product xymethylenoopolymer® is conveniently isolated in i" orm of a fine powder, as described in US Patent No. 3,254,053 "

The Qxysaethylene copolymer, according to its image, is generally made up of residual monomarem, Gosonoaieres _g Kata = »lysatox ¹ and methylene chloride diireh Waseiisa Tb @ fr © i"& Any known washing methods can be used, e.g. one or more washes with the first Wash with a catalyst agent, such as methyl alcohol or Is © f & pjlall & a subsequent WS-sohe iii W

The oxymethylene copolymers formed can be endblocked if one of the known processes is used, for example by acylation or esterification after the polymerization or even during the polymerization reaction by using selected chains such as methylal. Stabilizers, _e sB inhibitors ter cleavage, antioxidants and the like. Könaen also optionally the Gopolymeren in any suitably added or incorporated therein.

The oxymethylene copolymers formed as productsB. are thermoplastic materials, di © © inen melting point of at least 160 have ⁰ O, and usually at about 19ö ^Q ö are kneadable. The important aspect, however, is that the copolymers have an average molecular weight (Q-weight average) of up to about 500,000 and viscosity numbers

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(inherent viscosity) "to 5» O (measured at 6O ⁰ O in a 0.1 # solution in p-chlorophenol, which contains 2 wt .- $ α-Pineη).

The oxymethylene copolymers formed as a product can alone or in combination with oxymethylene polymers or. - copolymers of lower molecular weight by pressing, injection molding, extrusion, etc. into fibers, Foils, molded parts and the like are processed.

Examples

Production of an ionic salt catalyst p-chlorophenyldiazonium hexafluoroarsenate

63t8 pounds (0.5 mol) of p-chloroaniline (01- / QVNH ₂ ) were added to a mixture of 120 ml of concentrated hydrochloric acid (1.2 mol HCl) and 120 ml of water in a 11 beaker , 5 ⁰ C cooled. At this temperature, the largest T _e il of p-chloroaniline remained firm. A solution of 36.5 g (0.53 mol) of sodium nitrite in 75 ml of water was added in small portions with vigorous stirring while maintaining the temperature at about 5 ° C. by adding a small amount of crushed ice as needed. Diazonization was complete when one drop of the solution diluted with 3 to 4 drops of water gave immediate blue coloration with potassium iodide starch paper. Virtually all of the solids were dissolved. A solution of 148.3 g (0.7 mol) Natriumhexafluorarsenat (NaAsFg) in 150 ml of water was prepared and cooled to about 5 ⁰ C. The cooled solution was slowly added to the diazonium salt solution while the latter was stirred well and its temperature was kept below 10 ° C. A white glossy crystalline product was precipitated. The mixture was allowed to stand for 10 minutes with frequent stirring to complete the reaction. The product was separated on a Buchner funnel and washed with ice water and ether. The raw p-Ohlor-

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phenyl diazonium hexafluoroarsenate was obtained in the form of small white shiny flakes. Ee was recrystallized from water by dissolving at about 40 ⁰ O and chilled in the refrigerator overnight. The umkristalliBierte material was obtained in the form of large plates with a melting point of 127 to 127.5 ⁰ O (dec.).

p-chlorophenyldlazonium hexafluoroantimonate

The procedure was the same as above for the division of Ol-ZoV ^ o ^^ ~ 6 ^tesonriel :) with the difference that 18f, 2 g (0.7 mol) NaSbFg instead of H8.3 g (0.7 mol) NaAsFg were used. The reaction also proceeded in the same way. The crude product was obtained in the form of grayish small crystalline particles. The recrystallized product was in the form of white platelets with a melting point of 120.5 to 121 ⁰ O.

p-chlorophenyldiazonium hexafluorophosphate

The hexafluorophosphate can be prepared in the same way as the arsenate.

The following table shows various copolymerization and homopolymerization versions with the catalyst described above. In each of these Copolymerisationsversuche 1.15 mole of trioxane with 0.048 moles of ethylene oxide at a temperature of 65 + 1 ⁰ O were copolymerized. The homopolymerization experiments were carried out in the same way, but with trioxane alone.

The catalysts used in each case and their amounts are given in the table. Likewise, some of the Experiments compiled in the table carried out with the addition of methylene chloride according to the invention.

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All polymerization experiments listed below were in the liquid phase and in bulk according to the invention carried out. The polymers formed in the experiments were isolated from the polymerization vessel and washed with a mixture of acetone and water, whereupon the molecular weight was determined.

Moles of monomer Comonomer OH ₉ Ol ₉ Molecular size Moles of catalyst
(x 1O ⁴ ) C. C weight (numbers
middle)
(Mn) (χ 10 ⁵ ) Catalyst a 21.5 - - 1.17 14.0 - - 2.06 8.05 - - 3.61 4.36 - - 2.75 1.61 - - 1.69. 0.982 - - 1.51 0.664 - - 1.03 5.88 ... 10 ml 1.36 3.64 - Il 1.71 2.62 - Il 1.90 1.26 - Il 1.25 0.303 - It 0.68 13.4 Ethylene oxide _ 0.989 8.64 Il 1.06 6.21 Il - 1.00 4.20 Il - 1.13 3.11 ti - 1.33 1.68 Il - 1.08 0.800 Il - 0.769 0.547 Il - 0.582 9.69 Il 10 ml 1.09 6.82 Il It 1.09 4.85 Il It 1.25

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- 14 - Moles of catalyst * OHoI ₅ 1906848 Moles of monomer Comonomer (x 10 ⁴ ) Ethylene oxide Cm Molecular size 3.41 η wi oh t (numbers 2.65 Il 10 ml medium c
(Mn) (χ 10 ⁵ ) 1.71 M. η 1.52 1.14 It Il 1.41 0.90 Il Il 1.38 0.68 Catalyst "b Il 1.13 - Il 0.97 24.0 - 0.82 10.7 - - 2.93 - - 3.10 1.92 Ml - 2.85 0.924 - - 1.60 31.8 - - 1.25 13.0 - 10 ml 0.91 5.55 - Il 3.43 1.84 Ethylene oxide It 2.73 17.9 Il Il 1.81 10.9 Il - 1.15 7.03 Il - " 1.91 5.03 Il - 1.45 3.61 It - 1.23 2.50 Il - 0.89 1.87 Il - 0.86 0.951 It - 0.81 14.6 Il - 0.62 10.4 M. 10 ml 0.49 6.24 Il ti 2.20 4.57 Il It 1.74 3.34 Il U 1.63 2.74 Il Il 1.50 1.49 Il 1.35 Il 1.11 0.74

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-.15 -

Moles of monomer Comonomer OH ₉ Ol Molecular weight Get the catalyst C. (Numerical mean) (x 1O ⁴ ) (Mn) (χ 10 ⁵ ) 0.81 Ethylene oxide 10 ml 0.61 Catalyst o- 20.4 Ethylene oxide ■ - 0.62 8.33 ti - 0.40 3.26 It - 0.33 2.20 Il - 0.29 1.09 Il - 0.19 7.03 ti 10 ml 0.33 4.51 M. η 0.34 2.16 η Il 0.24 1.07 Il η 0.21

a β p-chlorophenyldiazonium hexafluorophosphate b «p-chlorophenyldiazonium hexafluoroarsenate ο = p-chlorophenyldiazonium hexafluoroantimonate

The above values were used to produce the graphical representations in Figures 1 to 5

Figures 1 and 3 show that the use of methylene chloride in the homopolymerization of trioxane essentially no beneficial effect on the molecular weight of the oxymethylene polymer formed, since the molecular weight is lower in most cases than without using methylene chloride.

In contrast to this, FIGS. 2 and 4 clearly show one Increase in molecular weight of copolymers by up to $ 35 if methylene chloride during copolymerization is used.

Fig. 5 confirms the additional limitation of the invention, namely on the use of methylene chloride in

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Combination with a salt of arsenic or Phosphorohio riden or fluorides. The increasing effect is not achieved with the St)] Tg catalyst.

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Claims (7)

Claims 1 .. Process for the production of oxymethylene copolymers, in which trioxane is copolymerized with at least one comonomer, characterized in that the copolymerization in the liquid phase in the presence of methylene chloride and salts as catalysts carries out the anion hexachloroarsenate, hexafluoroarsenate, hexachlorophosphate and / or hexafluoro contain phosphate and at the same time are stable and soluble in the trioxane and / or the comonomer. 2. The method according to claim 1, characterized in that «salts alkyloxonium salts, aryloxonium salts, Arydiazonium salts, hydrogen salts, or else alkyl carbonium salts, aryl carbonium salts and / or nitronium salts are used. J. The method according to claim 2, characterized in that that work is carried out with aryldiazonium salts, which are hexafluoroarsenate and / or hexafluorophosphate as the anion and in the aryl part with at least one of the substituents chlorine and / or nitro groups is substituted. 4. Process according to Claims 1 to 3 *, characterized in that that one trioxane with * a cyclic ether of the general formula (0CH ₂ ) _n copolymerized, where η is an integer from 0 to 2 means. 909838 / U25 5. The method according to claims 1 to 4, characterized in that one with amounts of about o, l to 2o % By weight, preferably about 1 to 10% by weight of methylene chloride, based on the weight of the trioxane used, works. 6. Process according to Claims 1 to 5, characterized in that that the salt catalyst and in particular the aryldiazonium salt in amounts of about 0.5 x Io «4
up to 2 χ Io moles per mole of trioxane is used. 7. The method according to claims 1 to 6 ^ characterized that one trioxane with ethylene oxide in the presence of p-chlorophenyldiazonium hexafluoroarsenate and / or p-chlorophenyldiazonium hexafluorophosphate polymerized, 909838/1 A25