DE3044940A1 - Catalyst for high mol. wt. polyoxymethylene prepn. - comprises ammonium lactamate esp. pyrrolidonate, piperidonate, lauryl-lactamate or capro:lactamate - Google Patents

Abstract

A catalyst for preparing polyformaldehyde comprises an ammonium salt of formula (I) A-N+R2R2R3R3 (I) (where R1-4 are (cyclo)alkyl or (alkyl)aryl and A is a lactamate residue of formula (II) and B is a 3-13C linear polymethylene chain in which one or more of the H atoms may be opt. substd. by (cyclo)alkyl or (alkyl)aryl). (I) has high activity with a practically quantitative yield in polyformaldehyde. The polymers have narrow mol.wt. distribution, high mol.wt. and high bulk density so that they can be easily removed from the reaction medium by decantation or filtration. The filtered polymer has a low content of diluent. The catalyst residues do not have to be removed; they degrade during stabilisation of the polyoxymethylene and gps. e.g. esterification or etherification. Polymerisation can be carried out continuously.

Description

It is known that formaldehyde polymers or polyoxymethyl

lenes with a molecular weight of at least 10,000 due to their mechanical properties, such as toughness, hardness, resilience and exceptional Dimensional stability and due to their dielectric properties as p las ti -sche plastics suitable for technical purposes.

These polyoxymethylenes are generally made by polymerization of anhydrous, monomeric formaldehyde in a liquid, organic reaction medium within a wide temperature range and in the presence of a polymerization catalyst manufactured. Examples of known catalysts for the polymerization of formaldehyde are amino compounds such as aliphatic, cycloaliphatic and aromatic amines, or arsines, stibines and phosphines, in which those on arsenic, antimony or phosphorus Bound hydrogen atoms substituted by organic hydrocarbon radicals are.

Other catalysts that can be used for the polymerization are organometallic Compounds, metal carbonyls, onium compounds, and oxidation-reducing agents (See U.S. Patents 2,734,889, 2,826,286, 2,844,561, 2,848,437, 2,994,687, and 3,027,352).

The use of the above-mentioned catalysts does not lead to fully satisfactory results, mainly because often the molecular weight of polyformaldehyde cannot be effectively controlled. That has the disadvantage that the polyoxymethylenes produced vary widely in their molecular weight can. Another disadvantage of the numerous catalysts, including the special one active, lies in the need that the catalyst residues from the polymer must be removed. The presence of this back stands, in particular in the case of metallic catalysts, causes degradation reactions during processing the polyoxymethylenes in the molten state. The degradation of the polymer makes by loss of polyformaldehyde, discoloration and deterioration of the physical and thermal properties of the molded parts are generally noticeable. The secondary reactions caused depend on the type of retall catalyst used away. For example, cause alkali or alkaline earth metals due to a crotonaldehyde-like Catalysis the formation of discolored products. To maintain desired properties, especially of a certain color, it is therefore necessary to remove the metallic residue to remove. Due to the low solubility of the catalytic residues in organic solvents and reagents as used in the following steps Stabilization of the polymer, such as esterification and etherification, can be used, are cleaning treatments to achieve the required degree of purity arduous.

In some cases the catalytic residues cause decomposition the reagents used for stabilization. This can then be done, for example observe when alkali metal residues are among the esterification of crude formaldehyde polymer come into contact with acetic anhydride under suitable conditions.

The object of the invention is to address the disadvantages listed above to overcome the use of catalysts in the polymerization of formaldehyde. The problem is solved by using new catalysts.

The invention thus relates to that characterized in the claims Object.

The new catalysts of the general formula I according to the invention are salts in which A) an anionic lactam rest and (+) N (R1, R2, R3, R4) represents a quaternary ammonium radical. The meaning of the radicals A, R1, R2, R3 and R4 are reproduced in the claim. Preferred examples of the rest are α-pyrrolidonate, W-piperidonate, ε-caprolactamate and # -lauryl lactamate groups.

Examples of the cationic radical (+) N (R1, R2, R3, R4) are the tetramethyl, Tetraethyl, tetrapropyl, tetrabutyl, tetraheptyl, phenyltrimethyl, benzyltrimethyl and cyclohexyltrimethylammonium group.

The compounds of general formula I according to the invention are for the polymerization of anhydrous monomeric form aldehyde in non-polar solvents effective catalysts to obtain polyoxymethylenes of high molecular weights will. The use of the catalysts according to the invention has the following in particular Advantages: - A high catalytic efficiency that allows polymerization at low Permitted content of free monomer in the reaction medium, the formaldehyde used is converted into polyformaldehyde in practically quantitative yield; - the education of polymers with limited molecular weight distribution, which is expressed by the ratio Mw / Mn, where Mw is the weight average molecular weight and E represent the number average molecular weight; as is known, these are physical and molecular properties of polyoxymethylene are of fundamental importance for the properties of the polymeric product, especially with regard to its toughness, Rebound resilience, resistance to downforce and dimensional stability the molded parts; - The polyformaldehydes obtained do not require cleaning or special treatments to remove catalyst residues to remove; in fact, these residues are subject to endgroup stabilization during stabilization of polyoxymethylene, for example, by esterification with acetic anhydride or Etherification with orthoesters thermal degradation, whereby they are practically removed; the behavior of the catalyst residues under the conditions of the stabilization treatment corresponds to that of quaternary ammonium hydroxides, which at temperatures above 1000C can be converted into tertiary amines, alkenes and water; - the possibility carry out the reaction in a continuous polymerisation process to be able to, with a high weight ratio of polyoxymethylene to liquid diluent is present in the reaction medium and this weight ratio values up to the order of magnitude of 1: 1 can achieve; - those obtained according to the process according to the invention Polyoxymethylenes have a high bulk density on the order of 0> 5 to 0.7 g / ml, they can easily be removed from the reaction medium by decanting or filtering are separated and the filtered polymer has a very low content on residues of the diluent.

The quaternary ammonium salts of lactams can be prepared according to the following general procedure: An anhydrous solution containing a certain amount of an alkali metal alcoholate, such as sodium methylate or potassium ethylate is contained with an anhydrous alcoholic solution in an equivalent amount of a quaternary ammonium halide, for example a chloride or bromide, mixed. The alkali metal halide formed settles in the solution or is made by adding a liquid in which the halide is not soluble, such as Ethyl ether, precipitated. After filtering off the alkali metal halide, the Solvent is distilled off under reduced pressure; these distance the solvent can optionally by adding an inert solvent, like benzene, will be facilitated, it will be the quaternary ammonium alcoholate behave as a residue that with a lactam in a slight excess, based on the stoichiometric amount, is added and in an inert solvent such as Ethyl ether or dioxane, is dissolved.

The desired compound is formed from the solution obtained in this way solid crystals generally by cooling and / or by adding a solvent, in which the compound is not soluble, precipitated.

The compound obtained can be used as a catalyst for polymerization of anhydrous formaldehyde can be used, the reaction in an inert liquid diluent is carried out as the reaction medium. The Catalyst Depending on the chosen diluent and the nature of its R1 to R4 residues be dissolved or suspended. If the catalyst is used in suspension, so it should be suspended in finely divided form. During the manufacture of the catalyst the precipitation conditions can be adjusted so that solid particles of the desired Size within a range of 5 to 300 microns, preferably 10 to 100 microns, can be obtained. However, the required particle size can also be achieved by grinding of the precipitate can be obtained under inert conditions.

For the polymerization of the formaldehyde, gaseous, anhydrous is used Formaldehyde in a diluent that is liquid under the reaction conditions which is inert and in which the polymer formed does not dissolve, with stirring initiated.

The amount of the catalyst can be 1 to 1000, preferably 20 to 500, Parts by weight per 106 parts by weight introduced Formaldehyde.

The diluents used must be inert, i.e.

they must not react either with the catalyst or with the polymer. Examples of diluents are ethers, such as diethyl ether, aliphatic hydrocarbons, such as pentane, hexane, heptane or octane, aromatic hydrocarbons such as benzene and toluene, and chlorinated hydrocarbons. Preferred diluents are Hydrocarbons with 3 to 10 carbon atoms.

For the production of polyoxymethylene with high molecular weights, which are more than 10,000, the use of formaldehyde is of high purity and drought required.

A sufficient degree of purity is achieved, for example, through the cleaning process behave as described in U.S. Patents 3,118,747, 3,184,900, and 4,203,735 is. In particular, impurities that cause the phenomenon must be excluded of chain transfers or those due to their polar nature in general react with Grignard compounds. The most common impurities are methanol, Water and formic acid, which act as chain transfer agents during polymerization act and thus influence the molecular structure of the polyoxymethylene.

Of course it is possible to change the molecular structure in the desired way to influence by the polymerization in the presence of small amounts more suitable Chain regulators, such as carboxylic acids and esters with at least 2 carbon atoms per molecule, aliphatic, cycloaliphatic and aromatic alcohols, carboxylic acid anhydrides, amides, imines and other polar compounds such as water will. These chain regulators generally have a corresponding effect Concentrations of 10 to 10,000 parts by weight per 106 parts by weight introduced Formaldehyde.

In this way, polyoxymethylery can be produced according to appropriate stabilization by injection molding, extrusion, spinning, im Rotoform processes and blow molding processes for suitable moldings and parts can be processed.

The polymerization temperature is not critical, in general it is it about -100 ° C to the boiling point of the diluent; However, it shouldn't be more than about 1000C. A temperature range from -30 to 70 ° C. is preferred.

The reaction is generally carried out at atmospheric pressure, However, a higher or lower pressure is also possible.

The polymerization of the formaldehyde can be discontinuous, semi-continuous or continuous processes. in the continuous process, the Catalyst as a suspension or solution in an inert organic ether in the Reaction are introduced. A continuous process is for example in U.S. Patent 3,458,479.

In each case, when the polymerization is complete, a suspension of the Behave polyoxymethylene, from which the polymer is obtained in granular form; if the reaction with a catalyst takes place in solution, the polymer becomes with a grain size of about 20 to about 700 microns, especially from about 20 to about 100 microns obtained; the reaction takes place with a catalyst in suspension, thus the polymer is obtained in a particle size of about 60 to about 700 microns. In the latter case, the particle size of the polymer depends on the values of the catalyst.

The bulk weight is also separated from the reaction medium and dried Polyoxymethylene depends on the way in which the catalyst was used. at Using the catalyst in solution is polyoxymethylene with a bulk density obtained from 0.15 to 0.25 g / ml. If the catalyst is in suspension, so will obtained a bulk density of 0.5 to 0.7 g / ml.

It is known that the polymer obtained by the polymerization contains formaldehyde polymer at least one terminal hydroxyl group per macromolecule, which is a thermal Causes instability of the polymer. To cause depolymerization at the end of the chain avoid, the hydroxyl groups are converted into ester or ether groups. this takes place, for example, by treatment with acetic anhydride or orthoformic acid methyl or ethyl ester or conversion into urethane groups by treatment with isocyanates Methods are known; they are described, for example, in US Pat. No. 3,875,117.

The polyoxymethylene treated in this way can be substituted with antioxidants ( Phenols or bisphenols) or other weakly basic substances are treated, which block formaldehyde and its oxidation products, such as formic acid. Examples of suitable basic compounds are polymers such as polyamides and Polyester amides. Typical stabilization methods are described in U.S. Patents 2,993,025 and US Pat 2 966 476.

The examples illustrate the invention. If not stated otherwise, Parts and percentages relate to weight.

Example 1 In a completely inert atmosphere there are 116 parts Sodium dissolved with stirring in 800 parts of anhydrous ethanol and then with 219.2 parts of tetramethylammo- sodium chloride in 800 parts of ethanol and 1400 parts of anhydrous ethyl ether were added.

The sodium chloride is filtered off; the solvents are taking distilled off under reduced pressure below 300C.

What remains is tetramethylammonium ethylate as a syrupy residue, that with 168 parts of pyrrolidone in 1400 parts of anhydrous ethyl acetate and then with 5000 parts of ethyl ether is added.

220 parts of a white fine powder are deposited from this solution, which consists of tetramethylammonium pyrrolidonate.

Implementation: 69> 5% F .: 150 to 15100 Grain size:> 125 microns = 2.5% 125-44 microns = 75.2% <44 microns = 22.3% The catalyst pr can be stored at room temperature in an inert atmosphere.

1000 parts of anhydrous heptane and 0.05 part of that obtained above Catalyst are placed in a reaction vessel, in which then pure, gaseous formaldehyde at a rate of 2.5 parts per minute vigorous stirring is initiated. The reaction is carried out under strictly anhydrous conditions carried out and initiated the monomer within 300 minutes, the reaction temperature is kept at 2500.

The polymer suspension obtained is filtered off and the polymer dried under reduced pressure at 50.degree.

There are 735 parts of the product in a yield of 98.0%, based on the formaldehyde, in powder form obtain.

Intrinsic viscosity: 4.21 dl / g (measured at 600C at a concentration of 0.5 g / dl in a solution in p-chlorophenol with 2% α-pinene).

Bulk density: 0s70 g / ml Grain size:> 350 microns = 8.2% 350 - 250 microns = 57.3% 250-125 microns = 32.2% (125 microns 2> 3% One part by weight the polymer is under strictly inert conditions with a reaction system, that of 1.5 parts of pure acetic anhydride and 3.0 parts of a mixture of C12-C13-C14n paraffins (in a ratio of 25: 25: 50) for 60 minutes esterified at a temperature of 153 to 1550C.

When the reaction has ended, the suspension is filtered off and the reagent is filtered off recovered by washing with toluene.

After drying under reduced pressure at 70.degree. C., the polymer becomes obtained again at 96.8.

Intrinsic viscosity: 4.20 dl / g bulk density and grain size: essentially unchanged nitrogen content: # 2 ppm (in the analytical range) Thermal degradation test: K220 - thermal degradation at 2200C in a nitrogen atmosphere: rate of decomposition of the polymer in percent by weight per minute during the first 30 minutes.

The determination is made with the help of a thermobalance under a continuous Gas flow for cleaning degradation products performed, K220 = 0.07 B e i s p i e 1 2 Following the procedure of Example 1, tetramethylammonium caprolactamate is obtained manufactured.

F .: 123 ° C bulk density> 125 microns = 0.5% 125 - 44 microns = 43.2% <44 microns = 56.5% The powdery product is at room temperature in a stored in an inert atmosphere.

The formaldehyde polymerization is carried out according to Example 1, with the monomer at a rate of 2.5 to 5 parts per minute with stirring is introduced into 1000 parts of tetramethylammonium caprolactamate. To do this, in the reaction vessel placed 0.45 parts of n-propanol. The monomer is added during 200 minutes, the polymerization temperature is kept at 20 to 250C.

After the suspension has been filtered off, the polymer is reduced under reduced pressure Print dried at 590C. There are 485.5 parts of the polymer in one yield of 97.1%, based on the formaldehyde introduced, with the following physical Properties retained: inherent viscosity: 1.40 dl / g bulk density 0.61 g / ml grain size > 350 microns = 6.5% 350-250 microns = 35.2 ß 250-125 microns = 41.0% < 125 microns = 17.)% Part of the polymer is treated with acetic anhydride such as in Example 1 described esterified.

After the reaction has ended, 95.5% becomes stabilized polyoxymethylene obtained whose inherent viscosity is identical to that of the crude polymer. the Properties of powdery polyoxymethylene - the bulk density and the granule size -are essentially unchanged.

Nitrogen content: # 2 ppm (analytical range) Thermal mixer degradation test: K220 = 0.05 The polymer is placed in a column filled with diatomaceous earth (Celite) using dimethylacetamide stabilized with 1% diphenylamine as solvent and fractionated at certain temperatures. Analysis of the individual fractions gives a molecular weight distribution for the polymer, expressed in Mw / Mn of 2.08. The values for the weight average Mw were obtained using the light diffusion method as described in J. Pol. Sci. A-2, Vol. 4 (1966), pp.

described sit; 437 / the values for the numerical mean Mn are given by means of Pressure osmometry, described in J. Pol Appl Polymer Science, Vol. 1 (1959), p. 164, certainly.

The polyoxymethylene is 0.5 part of a block polyester amide in powder form mixed in, which consists of 92% t-caprolactam units and 8% 6-caprolactone units, and with 0.3% pentaerythritol tetra-ß- (4-hydroxy-3,5-di-tert-butylphenyl) propionate Mix and the mixture is in a single screw press at temperatures of 180 to 2000C fused to form granules. - The following experiments were carried out with the granules executed: melt index at 19500 with a load of 2160 g thermal mixer Degradation at 223 ° C in nitrogen: K220 The thermal degradation at 2000C in air - D220: The percentage weight loss of the polymer after 10 and 20 Minutes. The determination is made with the help of a thermal balance under continuous Removal of the decomposition product carried out in a gas stream. The results are reproduced in Table I under POM 2.

Furthermore, the polymer undergoes a special thermal treatment subjected at 2300C (test CR) using an apparatus for determination the melt index. The apparatus is charged with the granules and the melt index determined during different time intervals with a load of 2160 g.

In this way it is possible to change the fluidity and allow the molecular weight to be tracked over time and the color of the extruded To determine the product.

The results are summarized in Table II under POM 2.

Example 3 Diethyldioctadecylammonium caprolactamate is prepared according to the Preparation of the polymerization catalyst in Example 1 from diethyldioctadecylammonium chloride manufactured.

1000 parts of anhydrous toluene and 0.46 parts of the catalyst presented. Then it becomes pure gaseous formaldehyde initiated over 50 minutes at a rate of 2.5 parts per minute.

0.09 parts of n-butanol are also added to the reaction vessel, which is kept at 10 ° C.

After filtering the suspension, the polymer is reduced under reduced pressure Print dried at 500C. It will be 122.7 Parts of the polymer with a yield of 98.2% based on the monomer introduced with the following Properties retained: inherent viscosity: 1.82 dl / g bulk density: 0.20 g / ml grain size: > 88 microns = 10.2% 88-44 microns = 70.8% <44 44 microns = 19.0% One part of the polymer is esterified with acetic anhydride under those in Example 1 stabilized. The yield is 96.8%.

Nitrogen content of the polymer: # 2 ppm (analytical range) After the addition of stabilizers, the polymer is described as in Example 2 processed into granules. The results of those carried out with these granules Experiments are summarized in Tables 1 and II under POM 3.

Table I. Melt index, K220, D220,% % / Min 10 '20' POM 2 10.2 0.04 0.6 1.2 POM 3 1.9 0.04 0.6 0.9 Table II POM 2 POM 3 Dwell time, melting dwell time, melting-- Min. Index, color Min. Index, color g / 10 'g / 10' 5 15.4 white 5 3.4 white 10 15.2 "10 3.2" 15 16.0 "15 3.4" 20 16.3 "20 3.5" 25 17.1 "25 3.6" 30 18.3 "30 4.0" Example 4 46 parts of metallic sodium are reacted with 800 parts of anhydrous ethanol according to the process described in Example 1, an alcoholic solution of sodium ethylate being obtained. 644 parts of tetrabutylammonium bromide are then dissolved in 800 parts of ethanol as in Example 1. 352 parts of tetrabutylammonium piperidonate are obtained in the form of a white, crystalline powder.

F .: 161 ° C Grain size:> 88 microns = 0.9% 88 -44 microns = 26.9 % (44 microns = 72.2% The product is stored in a completely inert atmosphere.

In a polymerization vessel with 1000 parts of anhydrous hexane and 0.110 part of piperidonate becomes pure gaseous formaldehyde over 108 minutes initiated at a rate of 2.5 parts per minute. The polymerization temperature is kept at 35 to 400C.

After the reaction has ended, the suspension is filtered and the polymer dried under reduced pressure at 50.degree. There are 263.2 parts of polyoxymethylene in a yield of 97.5%, based on the monomer used, with the following Elgensehaften obtained: intrinsic viscosity: 2.25 dl / g bulk density: 0.68 g / ml grain size: > 350 microns = 2.4% 350-250 microns = 20.7% 250-125 microns = 33.9% <125 Micron = 43.0% Part of the polymer is etherified with a reaction system stabilized, which consists of 0.4 parts of triethyl orthoformate, 0.8 parts of dimethylformamide, 2 parts of heptane and 0.05 part of diethyl sulfate. The reaction mixture is Heated for 30 minutes to a temperature of 150 to 1520C. After filtering off the polymer is washed first with heptane and then with methanol.

After drying, the polymer is in a yield of 97.2 % with practically unchanged grain size and bulk density and the following properties obtained: - intrinsic viscosity: 1.78 dl / g - nitrogen content: # 2 ppm (analytical Range) - alkali stability see Table III.

Part of the polymer is in dimethylacetamide, the 1% triethanolamine contains, dissolved and heated to 150 to 1520C for 30 minutes, the ratio of Polymer to dimethylacetamide is 1:10. After the reaction has ended, it falls Polymer from cooling on cooling, is filtered off, washed with methanol and dried.

The remaining polymer is as alkali-stable fraction ASF in Table III listed under POM 4 in percent.

Further physico-mechanical properties are achieved after adding 0.8 % Polyphenylpyrrolidone with a molecular weight of 30,000 and 0.4 parts of 2,2'-methylene-bis- (4-methyl-6-tert-butylphenol) determined after the polymer treated in this way by extrusion into granules has been processed. The corresponding data are in Tables III and IV below POM-4 summarized. The polymer is fractionated according to Example 3 and a Molecular weight spread of 1.79 determined.

Example 5 1000 parts of toluene are added to a polymerization vessel and 0.050 part of tetrabutylammonium piperidonate (prepared according to the method described in the first part procedure described in Example 4). The mixture becomes pure gaseous Formaldehyde for 40 minutes at a rate of 2.5 parts per minute initiated. 98.5 parts of polyoxymethylene are obtained in a yield of 98.5% on the introduced monomer. The powdery polymer has the following Properties: Bulk density: 0.15 g / ml Grain size:> 88 microns = 9.4% 83 - 44 Micron = 74.2% <44 Micron = 16.4% The polymer is etherified according to the method described in Example 4 stabilized. 95.2% of the Product received.

The polymer, whose physical properties remain unchanged are subjected to the following tests: Inherent viscosity 1.35 dl / g alkali stability - ASF see Table III, under POM 5 Determination of heat resistance and the physical and mechanical properties after adding additives and granulating according to the method described in Example 4, see Tables III and IV under POM 5.

Table III Melt index, ASF, K220, D220,% g / 101% / min. 10 '20' POM II 2.2 97.8 0.04 0.6 l, o POM 5 15.0 98.1 0.04 0.5 0.9 Table IV POM 4 POM 5 Tensile strength - kg / cm² 718 700 (ASTM D 638) Elongation - 638) 75 30.0 (ASTM D 638) / Impact strength Izod impact strength (with notch), 16 11.5 kg.cm/cm² (ASTM D 256) Example 6 Formaldehyde is polymerized over a long period of time according to Example 1 in such a way that heptane and tetramethylammoniumpyrrolidonate are fed in continuously and the suspension of the polymer formed is continuously removed.

First, pure, gaseous formaldehyde is converted into the Reaction vessel with 1000 parts of heptane and 0.08 parts of tetramethylammonium pyrrolidonate for 100 Minutes initiated at a rate of 2.5 parts per minute.

The suspension is then continuously drained while the reaction vessel is kept at a constant level by adding hexane.

During the 300 hour test, 7.2 parts of catalyst and 27 parts of ethanol are added.

During the test there are 14,420 parts of polyoxymethylene with an overall yield of 96.5% based on the monomer introduced.

After completion of the implementation, both the static parts and the walls of the reaction vessel, the outlet pipes for the suspension, etc., and the movable ones Parts of the polymerization vessel, such as the clockwork, are clean and free of deposits.

The polymer obtained has the following properties: Intrinsic viscosity: 1.28 dl / g 3chAtdensity: 0.59 g / ml Grain size:> 350 microns = 3.9% 350 - 250 microns = 47.3% 250-125 microns = 42,% - C 125 microns = 6.6% Part of the polymer is stabilized by esterification with acetic anhydride according to Example 1.

After the reaction has ended, 95.0% of the polymer becomes with the following Properties gained: - intrinsic viscosity: 1.29 dl / g - nitrogen content: <2 2 ppm - bulk density and grain size: practically unchanged from those of the crude polymer) - The polymer is fractionated according to Example 1. The molecular weight distribution has a ratio of Mw / Mn of 1> 95.

- Determination of heat resistance and physical and mechanical Properties after the addition of 0.5% polyamide-6 and 0.4% n-octadecyl-ß- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate and conversion into granules.

The results are summarized under POM 6 in Tables V and VI.

Example 7 Following the procedure described in Example 1, tetrabutylammonium - # - lauryl lactamate manufactured.

The product is used as a catalyst for formaldehyde polymerization used in a continuous polymerization process according to Example 6. Of the The experiment is carried out with benzene as the diluent for 300 hours. There are 44 550 parts of polymer with a yield of 99.0%, based on the introduced monomer, obtained with the addition of 9.0 parts of lactamate.

The polymer is produced under the conditions described in Example 4 stabilized. It is produced in 95.0% yield with the following properties won.

Intrinsic viscosity: 1.59 dl / g Nitrogen content: # 2 ppm Bulk density: 0.18 g / ml grain size:> 88 microns = 11.7 g 88 - 44 microns - 65.4% <44 44 Microns = 22.9% - Determination of the alkali-stable fraction - ASF, see POM 7 in Table V.

- The polymer is fractionated according to Example 1.

The molecular weight distribution has a ratio of Mw / Mn of 1.89.

Determination of heat resistance and physical and mechanical properties after the addition of 0.5% polyamide-6 and 0.4% n-octadecyl-ß- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate and conversion into granules brings about those listed under POM 7 in Tables V and VI Results.

Table V Melt index, ASF, K220, D220,% % / Min. 10 '20' POM 6 15.2-0.04 0.6 1.2 POM 7 6.1 97.8 0.03 0.4 0.9 Table VI POM 6 POM 7 Dwell time, melting dwell time, melting Color color Min. Index Min. Index 5 23.8 white 5 10.8 white 10 | 23.8 | "| 10 | 10.6 | ' 15 24.3 '15 10.8 20 25.2 20 11.0 | ' 25 26.2 "25 11.4" 30 27.8 "30 11.9"

Claims (8)

"Catalyst and its use for the production of polyformaldehyde Patent claims 1. Catalyst for the production of polyformaldehyde of the general formula I in which R1, R2, R3 and R4 are identical or different and denote an alkyl, cycloalkyl, aryl or alkylaryl radical and A () is the lactamate radical of the general formula II in which PM represents a linear polymethylene chain with 3 to 13 carbon atoms, in which one or more hydrogen atoms are optionally substituted by an alkyl, cycloalkyl, aryl or alkylaryl radical. 2. Catalyst according to claim 1 of the general formula I, in which A ( ) a W-pyrrolide nate »α-piperidonate, 8-caprolactamate or # -lauryl lactamate group is. 3. Catalyst according to claim 1 or 2 of the general formula I, in which the remainder (+) N (R1, R2, R3, R4) is a tetramethyl, tetraethyl, tetrapropyl, Tetrabutyl, tetraheptyl, phenyltrimethyl, benzyltrimethyl or cyclohexyltrimethylammonium group is. 4. Use of the catalyst according to claim 1 to 3 for the production of polyformaldehyde, characterized in that anhydrous, monomeric formaldehyde in an organic diluent that is liquid under the polymerization conditions, in which polyformaldehyde is insoluble and that to all reactants of the polymerization medium list inert, in the presence of a catalytic amount of the Polymerized catalyst. 5, embodiment according to claim 4, characterized in that one the catalyst in an amount of 1 to 1000 parts by weight per 106 parts by weight Formaldehyde adds. 6. Embodiment according to claim 4, characterized in that one the catalyst in an amount of 20 to 500 parts by weight per 106 parts by weight Formaldehyde adds. 7. Embodiment according to claim 4 to 6, characterized in that that ethers, aliphatic hydrocarbons, aromatic hydrocarbons or chlorinated hydrocarbons are used. 8. Embodiment according to claim 4 to 7, characterized in that that the polymerization is carried out at temperatures from -30 ° C to 700C.