DE1202495B - Process for the production of high molecular weight linear copolymers of formaldehyde - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

C08g

German class: 39 c -19

Number: 1202495

File number: M 56088IV d / 39 c

Filing date: March 13, 1963

Opening day: October 7, 1965

It is already known that formaldehyde copolymers can be prepared by using formaldehyde Comonomers in the presence of tertiary amines, pyridines, quinolines, phosphines or stibines polymerized.

The invention relates to a process for the preparation of high molecular weight linear copolymers of formaldehyde by polymerizing anhydrous formaldehyde with comonomers in an anhydrous inert solvent in the presence of aliphatic, aromatic or cycloaliphatic tertiary amines, pyridines, quinolines, phosphines or stibines at temperatures from -100 to +70 ⁰ C, which is characterized in that the comonomers are compounds of the general formula

R ₁ χ

R.

used, in which R ₁ and R _{2 are} identical or different alkyl radicals having 1 to 6 carbon atoms or phenyl radicals.

The first members of the aliphatic series of tertiary amines proved to be very active catalysts with alkyl radicals of 1 to 5 carbon atoms, such as trimethylamine, triethylamine, tripropylamine, Methaläthylpropylamin and Diethylmonobutylamin.

Preferably, amounts of catalyst between 0.001 and 2%, preferably between 0.01 and 1 percent by weight, based on the inert solvent used in the polymerization.

Organic solvents which do not react with the monomers or with the catalysts under the polymerization conditions and which preferably do not solidify at the reaction temperature can be used as solvents. For example, it is possible to use: aliphatic, cycloaliphatic or aromatic hydrocarbons such as propane, propene, butene-1, butene-2, isobutene, pentanes, n-heptane, isooctane, toluene and mixtures thereof, such as, for example, the C ₄ fraction obtained by petroleum cracking, or petroleum ether or ethers such as diethyl ether.

The polymerization is preferably carried out in the presence of low-boiling solvents or low-boiling solvents Solvent mixtures carried out, working at the boiling point of the solvent.

The polymerization can be both continuous and under different working conditions Process for the production of high molecular weight linear copolymers of formaldehyde

Applicant:

Montecatini Societä Generale per l'Industria
Mineraria e Chimica, Milan (Italy)

Representative:

Dipl.-Ing. Dipl.-Chem. Dr. phil. Dr. techn.
J. Reitstötter and Dr.-Ing. W. Bunte,
Patent Attorneys, Munich 15, Haydnstr. 5

Named as inventor:

Giulio Natta,

Gianfranco Pregaglia,

Giorgio Mazzanti,

Marco Binaghi,

Giancarlo Pozzi,

Nino Oddo,

Valentino Zamboni, Milan (Italy)

Claimed priority:

Italy March 16, 1962 (5233)

can be carried out intermittently. The catalyst or a solution can, for example, be the mixture be added to the monomers or the monomer solution. In the copolymerization of dimethylketene a gaseous formaldehyde stream can be introduced into an amine solution, while dimethyl ketene in the liquid state is gradually added during the reaction.

Examples of ketenes of the formula
Rix

in which R ₁ and R _{2 have} the aforementioned meaning,

509 690/491

3 4

are: dimethyl ketene, methyl ethyl ketene, diethyl ketene, These copolymers include those whose

Dipropyl ketene, diisopropyl ketene, dibutyl ketene, di macromolecules monomeric — C — CH ₂ units and hexyl ketene, dicyclohexyl ketene and diphenyl ketene.

Formaldehyde is decomposed in an anhydrous state. Ri O

turns and can be liquid or gaseous. In the 5 I Ii

Practice is a practically anhydrous formaldehyde, C - C

containing less than 0.5% and preferably less |

used as 0.1% water, which according to any- R

one of the known processes, such as pyrolysis

of p-formaldehyde or a trioxane or a 10 monomer unit in a molar ratio greater than 1 hemiformal can be obtained. contain, where R ₁ and R _{2 are} preferably methyl

The molar ratio between the two are mono- or phenyl, and copolymers whose macromers (formaldehyde and ketene) can be within molecules
further limits vary. It has a sizeable one

Influence on the course of the copolymerization and 15 γ

allows a number of copolymers with I H

different proportions of monomeric units in C - C -

to preserve the macromolecules. By upright |

obtain a ketene concentration greater than that of CH ₃

of formaldehyde in the liquid phase, in which 20

the copolymerization takes place, in the case of monomeric units in proportions of less than 20 percent by weight of symmetrical (R ₁ = R ₂ ) ketenes, crystalline percentages and preferably less than 10 percent by weight of copolymers of polyester structure can be obtained.

in the macromolecules of the two mono- The structure of such copolymers is derived from the

The deriving units alternate between 25 F i g. 1 to 4 can be seen in which
follow one another. Is marked with a large chain F i g. 1 the infrared spectrum of a pure polyoxy-

shows excess methylene sample with extremely long reaction times,

worked, copolymers can be obtained in FIG. 2 the infrared spectrum of a formaldehyde-dimethyl ketene copolymers which are not age-old and which are derived only from the ketenes. 30 sats, obtained according to Example 1, and
On the other hand, by working with a Fig. 3, the infrared spectrum of an alternating

Excess formaldehyde copolymers obtained, the dimethylketene-formaldehyde copolymers of poly-sequences contained monomeric units, which is represented by the ester structure.

Derive formaldehyde and which has a polyacetal structure, the samples of FIG. 1 and 2 were under analog

separated by ester groups 35 reaction conditions prepared. Your limit viscosi

actions are almost the same. It can be clearly seen that

0 i _m spectrum of the polymer of F i g. 2 some Il special absorptions in the range of 5.76, 8.60,

CC - O - CH ₂ - 11.55 and 13.08 µ. are present that do not contain the polyoxy

I can be assigned 40 methyl chains (Fig. 1),

However, R ₂ are characteristic of ester groups.

In Fig. 4 are the X-ray diffraction spectra. Taken with a Geiger counter, by modifying the working conditions, from a pure one and the rate of addition of the monomers polyoxymethylene (A) and of an alternating one the ester groups mentioned can be incorporated into the polyacetal formaldehyde-dimethylketene copolymer with poly chains shown either in random distribution or in a block ester structure (B).

moderate distribution (as shown in Table I, the properties such as the infrared

of chain fractions resulting from alternating polyester determination of the ester groups in the chains and the Polyoxymethylene consequences exist). Copolymers, with terminal hydroxyl groups of copolymers, which those obtained from formaldehyde and a ketene are derived from formaldehyde and dimethyl ketene monomeric units in unchanging resemblance to those of a pure polyoxymethylene, Sequence are distributed, represent new products. Manufactured under the same conditions.

According to the method of the invention, it should be pointed out that molecular linear copolymers in which the number of terminal hydroxyl groups in pure macromolecules monomeric - O - CH ₂ units 55 polyoxymethylene is considerably higher. This shows and monomeric units of the formula that in the copolymers some ester groups are chain

form end groups. From the in Table I again-Ri 9 given values, the higher thermal

1 ii mixed stability of the non-alternating copolymers C - C - 60 (Fig. 2) noted versus pure polyoxymethylene

will. The crystallinity of the non-old-R ₂ alternating copolymers containing less than 10%

Units derived from keten are according to the

where R ₁ and R _{2 are the} same or different and X-ray determination is practically the same as that of alkyl radicals having 1 to 6 carbon atoms or pure polyoxymethylene. Denote the melting temperatures phenyl radicals containing, wherein the copolymers mentioned the other hand, are slightly lower various monomeric units at least in part and may be 140-175 ⁰ C. These are wisely distributed in a non-alternating sequence. from a practical point of view

considerable advantage because of the mechanical properties of the non-alternating copolymer remain practically the same as that of the pure polyoxymethylene, since their crystallinity is practically equivalent is, the slightly lower melting point, however, the processing of the polymer during production molded objects by limiting the decomposition reactions.

The copolymers produced according to the invention are for applications in the plastics field, particularly suitable for making shaped objects. The obtained by alternating copolymerization Highly crystalline copolymers can be produced by extrusion in the molten state or from solutions Result in fibers which can be oriented by stretching. They show a high degree of crystallinity along the fiber axis and can be used as textile fibers. The non-alternating copolymers with predominantly polyacetal structure result in homogeneous compression molding at 160 to 180 ° C translucent films, which have high toughness and resistance to repeated bending stress own. Thermally stable copolymers rich in formaldehyde can be obtained by varying the ratio between the two monomers during the polymerization and Conditions are used in which the reaction proceeds rather slowly. It's that way possible to obtain macromolecules that have a polyacetal structure, but terminal sections Contain that from chain parts with polyester structure and thus from alternating formaldehyde-ketene sequences exist.

The thermal stability of these copolymers with a predominantly polyacetal structure can also be known in Way by subsequent chemical measures, such as blocking the end groups of the Polyoxymethylene sequences ending in a hemiacetal group can be achieved. This blockage can be caused by Acetylation can be achieved. Antioxidants, thermal stabilizers, Optical stabilizers, lubricants, plasticizers or pigments can be added to the copolymer can be added to it for specific processing conditions or areas of application to make suitable.

The properties of the copolymers listed in the examples can be determined as follows:

1. Limiting viscosity ^ inherent)

In relative viscosity

^ inherent -

where the relative viscosity is the ratio between the viscosity of the solution and that of the solvent and C is the concentration of the solute in grams per 100 ml of solution. The determination was ml at 15O ⁰ C in dimethylformamide containing 1% diphenylamine in concentrations of 0.5 g / 100 is performed.

2. Weight loss at 16O ⁰ C. The determination was performed by placing about 0.1 g of the product in the presence of air in a held at 160 ⁰ C oven introduced and the weight loss of the sample was determined after 60 minutes.

3. Determination of the terminal hydroxyl and ester groups.

a) The percentage of hydroxyl groups contained in the polymer is expressed as moles - CH ₂ OH groups per 1000 g of polymer. The determination is carried out by infrared absorption spectrography on the basis of the intensity of the band due to the stretching vibration of the hydroxyl groups. The sample is examined in the form of a laminate obtained by high pressure sintering with a thickness of 0.1 to 0.2 mm. The thickness determined with a comparimeter is uniform over the entire laminate with a tolerance of 10%.

b) The percentage of sterile groups in the polymer, expressed as the proportion of dimethylketene, is determined by infrared absorption spectroscopy on the basis of the intensity of the band due to the stretching vibrations of the group

Il
- C - (OR)

certainly. The sample is examined as a film obtained by rapidly melting a sample in a press at 170 ° C. to a thickness of about 0.1000 mm.
The infrared absorption is measured in a Perking-Elmer two-beam spectrophotometer with a sodium chloride prism in the zone between 2.1 and 6.8 μ.
The optical density found is given by the absorption coefficient of the - CH ₂ OH and

Il
- C - O - CH ₂ groups

and divided by the thickness in microns.

4. The melting point is under a polarizing microscope with crossed Nicols with a Heating rate of 1 ° C./min on a product which has crystallized after prior melting certainly.

5. Thermal degradation constant. The thermal stability was based on the constant of the degradation rate determined at 220 ° C under nitrogen. The experiment was carried out by means of an automatically writing thermal weighing device of Eyraud type by reducing the loss of volatile matter at 222 ° C of 150 mg Polymer was measured down to a residue of less than 40%.

Unexpected technical advantages of the method according to the invention over the known methods are the following:

A. Compared to the known copolymers obtained by cationic polymerization:

1. It is not necessary to start from trioxane in order to produce high molecular weight copolymers obtain.

2. Careful cleaning is not necessary to remove the residues of the acidic catalyst (since basic catalysts are used).

B. Compared to the known copolymers obtained by anionic polymerization:

1. The copolymers according to the invention are thermally more stable without causing acetylation requirement.

2. Purification is not required to remove the acidic residues of the acetylation.

It should also be noted that the copolymers after

IR analysis

- CH ₂ OH groups 0.08 mol / kg

Copolymerized dimethylketene about 2.5Ge

weight percent

Melting point 169 ^° C

Comparative experiment

For comparison, an analogous preparation was carried out in the absence of dimethylketene. Man

According to the process of the invention, 20 g of a product with the following was obtained ^{by about 10 ° C}

Characteristics:

Intrinsic viscosity 1.2

Weight loss (at 160 ⁰ C) at 8 ° / ₀

IR analysis

- CH ₂ OH groups 0.26 mol / kg

Ester groups absent

Melting point 175 ^° C

The F i g. 1 and 2 represent the infrared spectra of these

have a lower melting point than the homopolymers. This is a notable advantage in that these copolymers can be used at lower temperatures, that is, decomposition reactions be avoided.

Another advantage of the copolymers according to the invention is their wide melting range and the The fact that they therefore become plastic before they melt. ,., _,,,

The following examples illustrate the invention. 20 ^{Demen VoduKte aar} -

Example 2 Example 1

From a glass reactor provided with a stirrer and kept at 20 ° C., repeated

alternating flushing and evacuation with nitrogen 25 aldehyde supply and 5 ml after completion of the mold Air removed. 300 ml anhydrous toluene, entaldehyde supply. 21 g of a product were obtained holding 10.36 ml of dissolved triethylamine (0.1 weight percent based on the solvent) were then filled in under vacuum. The residual pressure in the reactor was about 100 mm Hg. 30

Separately, 200 g of essentially anhydrous cyclohexyl formal were decomposed ^{by heating to 135 to 145 ° C.} The gaseous anhydrous formaldehyde developed in this way is passed through three glass coils connected in series and kept at -15 ° C. and then fed to the reactor containing the toluene. The decomposition temperature of the hemiform is controlled so that a constant pressure of about 600 mm Hg is maintained in the reactor. At the same time, gradually (a total of 40 5 minutes, the addition of one 5 ml) of dimethylketene are introduced into the reactor. Monomers during the addition of the other mono- After 20 minutes, the supply of the two monomers is interrupted. After 25 minutes, the mixture is terminated and the reaction mixture is terminated with the addition of monomers and the reaction mixture is kept stirring at 20 ^° C. for a further 15 minutes with stirring at 20 ^° C. for a further 15 minutes. The pressure in the reactor decreases during this 45 period. A product of the following period is obtained from its initial value. The Sus properties:

The process conditions of Example 1 were used, but 10 ml of dimethylketene in two Approaches used: 5 ml before starting the molding

the following properties:

Intrinsic viscosity 0.9

Weight loss (at 160 ° C) 5%

IR analysis

- CH ₂ OH groups 0.06 mol / kg

Copolymerized dimethylketene about 6.5 percent by weight, melting point 160 ° C

Example 3

The procedure is as in Example 1, but the addition rates and conditions of the two Monomers varied. They will take turns during

pension of the copolymer is filtered under vacuum, the product is repeatedly washed with acetone and then for 4 hours at 6O ⁰ C dried. 26 g of product are obtained with the following properties:

Intrinsic viscosity 1.3

Weight loss (at 160 ° C) 2.0%

Intrinsic viscosity 1.1

Weight loss (at 160 ⁰ C) 6 ° / ₀

IR analysis

- CH ₂ OH groups 0.12 mol / kg

Copolymerized dimethyl ketene about 3 weight percent

Melting point 167 ^° C

properties rehearse Limit
viscosity Table I.
the formaldehyde-dimethylketene copolymers Copolymerized
Dimethyl ketene in
Weight percent ² ) Roentgen-
crystallinity
° / o Thermal degradation
constant -ST ₂₂₁₁
% / min example 1
Example 2
Example 3
Pure polyoxymethylene 1.3
0.9
1.1
1.2 Final '
- CH ₂ OH-
groups
Moles / kg about 2.5
about 6.5
about 3
absent 74
76
75
75 2.5
2
4th
10 0.08
0.06
0.12
0.26

² ) Polyoxymethylenes obtained under the same conditions as in the previous examples (see Example 1).

² ) CH ₃ O
- C - C groups.

CH ₃

9 10

Example 4 to 6

The procedure was as in Example 1, except that those listed in Table II below were given Catalysts used. The properties of the polymers obtained are also given in the table remove.

Table II

example catalyst concentration
with reference
on the
solvent
in weight
percent Received
Polymer
G Intrinsic viscosity IR analysis
copolymerized
Dimethylketene
% 4th
5
ί 6 Tributylamine
Hexamethylenetetramine
Pyridine 0.2
0.1
0.3 20th
14th
24 1
0.7
1.9 3
3
3.5

Example 7

300 ml of toluene, and a glass tube containing 0.4 ml of triethylamine [N (C ₂ H _{5) 3]} were placed in a 500 ml glass reactor at 20 ⁰ C under nitrogen. The internal pressure is reduced to 100 mm Hg by connecting the reactor to a water jet pump and then the tube is broken under vacuum.

The reactor is connected to a generator of gaseous anhydrous formaldehyde and immediately then 30 ml of dimethylketene were quickly added via a dropping funnel. The supply gaseous Formaldehyde is regulated in such a way that the pressure in the reactor is kept at about 600 mm Hg. The solution slowly becomes discolored; after 30 minutes, the aldehyde feed is interrupted and that Stirring continued for a further 15 minutes in order to use up the formaldehyde still present. The reaction product is treated with methanol, leaving a finely divided white polymer slowly decanted. After repeated washing with methanol, the polymer is filtered and treated with 40 to 50 ° C dried under vacuum; it has a weight of 24 g.

The crude, highly crystalline polymer melts at about 210 ^° C. The infrared spectrum shows the presence of a few polyoxymethylene sequences together with a high proportion (about 80 mol percent) of a polymer with a polyester structure. The determined in tetrahydronaphthalene at 150 ⁰ C intrinsic viscosity is 0.27. If the polymer is ^{heated to 200 °} C. for 30 minutes, it shows a weight loss of 5%.

Examples

300 ml of toluene are placed in a 500 ml glass reactor equipped with a cooling jacket, a propeller stirrer and a dropping funnel. The temperature of the cooling jacket is by circulating a solution of carbonic acid in methanol - regulated 20 ⁰ C and the reactor brought by connecting it to a water jet pump to a pressure of 20 mm Hg. Under vacuum, 0.4 ml of triethylamine are introduced through a rubber membrane using a siphon and the apparatus is connected to a source of gaseous formaldehyde. The supply of gaseous formaldehyde is regulated so that the pressure in the reactor is kept at about 600 mm Hg. Immediately thereafter, 30 ml of dimethylketene are introduced, the mass being kept in motion. The mixture becomes almost colorless after 10 minutes

ao a further 20 ml of dimethylketene were added. Formaldehyde is passed in for a further 10 minutes and then the reaction is interrupted by adding methanol. The polymer is decanted and repeatedly washed with methanol and dried in air at about 50 ⁰ C. 29 g of polymer are obtained in this way.

The infrared spectrum shows the absence of a polyacetal structure in the polymer. The crude polymer melts at 215 ° C.

Example 9

300 ml of anhydrous toluene are placed in a a on - introduced equipped cooled 20 ⁰ C cooling jacket, a stirrer, a dropping funnel and a formaldehyde inlet tube 500-ml glass flask. The internal pressure is then adjusted to 20 mm Hg (absolute) using a water jet pump. While the apparatus is kept under vacuum, 4 ml of a 1.1 molar solution of trimethylamine in toluene are introduced through a rubber stopper by means of a pipette. Immediately thereafter, the introduction of gaseous formaldehyde is started, and at the same time 50 ml of dimethylketene are added via the dropping funnel. After 20 minutes, the introduction of formaldehyde is interrupted and, after a further 5 minutes, the mixture is taken up with methanol.

The precipitate weighs after repeated washing with methanol and drying in air at 4O ⁰ C 39 g and is soluble to 94% in boiling chloroform. The fraction soluble in chloroform has a melting point of 136 ° C. and, according to infrared analysis, appears to contain about 10% formaldehyde, the monomeric units of which participate in the ester groups. Consequences of polyacetal are absent.

Example 10

300 ml of anhydrous toluene are placed in a 500 ml reactor introduced, which is cooled to 0 ° C by means of a cooling jacket and a dropping funnel and has a formaldehyde introduction pipe. The internal pressure is increased by means of a water jet pump

6g set about 20 mm Hg. While the apparatus is kept under a vacuum, means are used injected 0.4 ml of triethylamine into a pipette. Immediately thereafter, the supply becomes gaseous

509 690/491

Formaldehyde (from any suitable source) and at the same time 20 ml of one 50 percent by volume solution of diphenylketene in toluene added via the dropping funnel. Under Continuing the introduction of formaldehyde so that the internal pressure is about 600 mm Hg 5 ml of a solution of diphenylketene in toluene four times at 3 minute intervals, in total 20 ml, added. After 18 minutes the reaction is interrupted by adding methanol. the After repeated washing with methanol and drying in air at 40 ° C., the amount of polymer is 21g. The melting point is around 150 ° C.

Example 11,.

A 1-1 reactor is used, which is equipped with a stirrer, cooling jacket, two dropping funnels, formaldehyde inlet pipe and another pipe which is connected to a device for maintaining the internal pressure of the reactor at a few millimeters Hg above atmospheric pressure. The air is removed from the reactor by repeated flushing with nitrogen, the cooling jacket is cooled to -30 ° C. and 450 ml of anhydrous n-heptane are introduced into the reactor, as 37.5 mg of triphenylphosphine dissolved in 50 ml of n-heptane are over one dropping funnel and 46 ml of n-heptane and 4 ml of dimethylketene fed through the other dropping funnel. As soon as the internal temperature reaches -2O ⁰ C, 14 ml of triphenylphosphine solution are added dropwise from the first dropping funnel and immediately thereafter the introduction of gaseous anhydrous formaldehyde at a rate of 2.1 g / min is started. At the same time, the dimethyl ketene solution is added dropwise from the second dropping funnel at a rate of 2.5 ml / min. About 3 ml of triphenylphosphine solution are added 2 minutes after the addition of the catalyst and then every 2 minutes. An excess of methanol is added 20 minutes after the start and the supply of formaldehyde is interrupted. The polymer is filtered, washed with methanol and dried in air at 40 ° C. for 24 hours. The properties of the product obtained are given in Table III.

Example 12

It is the same apparatus as in Example 11 is used, however, made with regard to the method, the _Sc following amendments:

1. 30 mg triphenylphosphine in 50 ml n-heptane are added to the first dropping funnel.

2. 47 ml of n-heptane and 3 ml of dimethylketene are poured into the second dropping funnel.

3. At the beginning of the polymerization, 15 ml of triphenylphosphine solution are introduced and then every 2 minutes a further 5 ml of the same solution is added.

4. The dimethyl ketene solution is added at a rate of 3.4 ml / min.

5. The gaseous formaldehyde is introduced at a rate of 3 g / min.

6. The polymerization is interrupted 15 minutes after the start.

The properties of the product obtained are given in Table III.

Example 13

The polymerization is carried out in the apparatus and according to the technique of Example 12, but the cooling jacket kept at +10 ^0C. The properties of the product obtained are given in Table III.

Example 14

The procedure of Example 12 is followed, but the catalyst solution in two proportions of 25 ml, one added at the beginning and the other after 8 minutes. The properties of the product obtained are given in Table III.

Example 15

The procedure of Example 12 is used, but one instead of the triphenylphosphine solution Solution of 0.016 ml of triethylamine in 50 ml of n-heptane is used. The properties of the product obtained are given in Table III.

Example 16

Using the same procedure as in Example 12, a solution of 0.016 ml of triethylamine in 50 ml n-heptane is used and all of the catalyst is added at the beginning of the polymerization.

In the Examples 11 to 16 obtained according to copolymers unstable at 16O ⁰ C fraction is present, which consists of low molecular weight formaldehyde homopolymers. This portion is removed by heating to 165 ° C for 6 hours. The properties of the purified polymers are given in Table III.

Table III

Raw At 165 ⁰ C Terminal ones Copolymerized Intrinsic viscosity Thermal degradation example Polymer unstable part CH ₁ OH Dimethylketene constant km G in percent by weight Moles / kg in percent by weight 0.6 % / min 12th 45.3 25th 0.05 3.7 0.63 0.15 13th 43 20th 0.04 2.4 0.73 0.21 14th 34 16 0.035 1.6 0.57 0.12 15th 37 18th 0.045 2.5 0.65 0.24 16 44 27 0.045 2.6 0.57 0.05 17th 46 24 0.04 2.6 0.08

Example 17

It is equipped with a stirrer, a cooling jacket, two dropping funnels, and a formaldehyde inlet tube 1-1 reactor equipped with a reflux condenser was used. At the top of the reflux condenser is a device attached to the internal pressure of the reactor to a few millimeters Hg above atmospheric pressure to keep.

The air from the reactor is removed by repeated purging with nitrogen and then the cooling jacket - 10 ⁰ C and cooled to -7O cirkuliert a cooled ⁰ C methanol in the cooler.

450 ml of anhydrous butene-1 are introduced into the reactor, while 56 mg of tributylamine, diluted with 50 ml of n-heptane, are poured into one of the two funnels. At the same time, 4 ml of dimethylketene and 46 ml of n-heptane are poured into the other funnel. The reactor is connected to the formaldehyde source (2.7 g CH ₂ O per minute) and at the same time 15 ml of the tributylammon solution and 15 ml of the dimethyl ketene solution are introduced via the funnel. The rest of the solutions are then added simultaneously at a rate of 5 ml / 2 min.

15 minutes after the start, the polymerization is interrupted by adding methanol.

The thus separated polymer has, after washing with methanol and drying in air at 4O ⁰ C for 24 hours, a weight of 40.5 g and has the following properties:

At 165 ⁰ C unstable portion 16%

Degradation rate at 222 ° C .. 0.06% / min
Intrinsic viscosity 0.6

Example 18

35

The same apparatus as described in Example 17 is used, but as a solvent a mixture consisting of 250 ml of n-heptane and 200 ml of butene-1 was used. The properties of the polymer thus obtained are shown in Table IV.

Example 19

The process is as described in Examples 17 and 18, but carried out, the reactor cooling jacket at - 50 ⁰ C cooled and used as a solvent 450 ml of propylene. The properties of the polymer thus obtained are shown in Table IV.

Example 20

The polymerization is carried out according to the guidelines of Examples 17 to 19, but as

Solvent 450 ml petroleum ether with a boiling point between 30 and 50 ⁰ C used and the reactor is not cooled by the cooling jacket. The properties of the polymer thus obtained are shown in Table IV.

Example 21

The process is carried out as described in Example 17, but 450 ml of a solvent Mixture composed of hydrocarbons with 4 carbon atoms obtained by fractionation of the products resulting from petroleum cracking is used. The characteristics of the so obtained polymer are shown in Table IV.

Table IV

Poly not Thermal Limit ° / o
Dimethyl at merisat SIaDUC stability vis keten im game G fraction
at 165 ° C kosity Copoly-
merisat 19th 36.8 10 0.1 1.24 2.8, 20th 34 12th 0.1 0.8 3.2 21 24 15th 0.08 0.6 3.2 22nd 38 12th 0.08 0.84 3.1

Claims (1)

Claim: Process for the production of high molecular weight linear copolymers of formaldehyde by polymerizing anhydrous formaldehyde with comonomers in an anhydrous inert solvent in the presence of aliphatic, aromatic or cycloaliphatic tertiary amines, pyridines, quinolines, phosphines or stibines at temperatures from -100 to +7O ⁰ C, characterized in that the comonomers used are compounds of the general formula used, in which R ₁ and R _{2 are} identical or different alkyl radicals having 1 to 6 carbon atoms or phenyl radicals. Considered publications: German Auslegeschriften No. 1,037,705,1 065 173; U.S. Patent No. 2,296,249. For this purpose 2 sheets of drawings 509 690/491 9.65 © Bundesdruckerei Berlin