DE1190189B - Process for the preparation of copolymers of trioxane - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

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C08g

German class: 39 c-19

D43889IVd / 39c
August 29, 1959
April 1, 1965

From US Pat. No. 2,795,571 it is known to use trioxane with ionic catalysts, such as Antimony trifluoride, zinc fluoride, hydrofluoric acid inter alia, to convert into high molecular weight polyoxymethylenes.

The polymers obtained in this way are, however, both thermally and chemically unstable, since obviously the end groups introduced into the polymer chains according to these methods only belong to the macromolecules able to give insufficient stability.

It is also known from British Patent 796 863 to use anhydrous formaldehyde z. B. aralkyl ethers, carboxylic anhydrides, esters or sulfides in the presence of a polymerization initiator, such as. B. a quaternary ammonium salt, to polymerize. The aralkyl ethers, carboxylic acid anhydrides, esters or sulfides serve as carriers, this results in polyoxymethylenes which are stabilized at at least one end group.

It has now been found that end-group-stable copolymers of trioxane can be obtained by polymerization of anhydrous trioxane with an oxygen-containing compound by means of ionic catalysts, optionally in inert solvents, can be prepared if the oxygen-containing compound / i-propiolactone used.

/ 2-propiolactone is used in amounts of 0.001 to 50 percent by weight, based on trioxane, used. Trioxane is found in both molten and dissolved State used. Organic solvents are used as solvents. All respondents, d. H. Trioxane, / 3-propiolactone, organic solvents and catalysts must be largely anhydrous.

The polymerization can be carried out at normal or slightly elevated temperature.

The excreted polymer is diluted by washing with methanal and extraction with Sodium hydroxide solution freed from small, low molecular weight fractions or initiator residues.

When the experiment is carried out accordingly, the yields are almost quantitative. The molecular weights the polymers can be varied within wide limits by suitable metering of the chain transfer agents thus the softening point can be adjusted as desired.

It is also possible to add known plasticizers, stabilizers, antioxidants to the polymers, likewise fillers and / or dyes, such as glass fibers, slag wool or, advantageously, highly disperse ones active fillers, such as alkaline soot, oxides of metals or metalloids, such as aluminum oxide, Process for the production of copolymers !! of trioxane

Applicant:

German gold and silver refinery

formerly Roessler,

Frankfurt / M., Weißfrauenstr. 9

Named as inventor:

Dr. Werner Kern,

Dr. Volker Jaacks, Mainz

Titanium oxide, zirconium oxide or silicon oxide, which by converting volatile compounds of these substances higher temperatures can be obtained in an oxidizing or hydrolyzing medium.

In this way, moldings are obtained which are tough and elastic, do not wear off with alkalis, are quite resistant to acid, when heated to 180 ° C for 1 hour only depolymerize slightly.

The copolymers produced according to the invention are made by the processes customary for thermoplastics to moldings by injection molding, rolling, pressing and others. processed and for coating Objects used.

The technical progress of the process according to the invention over the process of the British Patent 796 863 is that the polymers in the polymerization of trioxane with the invention Compound used are obtained, are thermally completely stable. By Polymerization of formaldehyde with carriers are obtained but - by the opposite of trioxane completely different running polymerization process - not thermally in that Dimensions stable.

example 1

8 g of anhydrous trioxane and 2 g of ß-propiolactone were dissolved in 10 ml of methylene chloride at 20 ° C. A diluted solution was slowly added to this solution Solution of Borfluoridätherat in methylene chloride added dropwise until the beginning of the polymerization made noticeable by the turbidity of the mixture. After completion of the reaction, the sucked off polymer was boiled with

509 557/475

Diethyl ether freed from adhering boron fluoride. The melting point of the copolymer thus obtained is about 120 ° C. It has very good thermal stability even at much higher temperatures. After rapid decomposition of 5 percent by weight of the unstable fraction, the copolymer of trioxane showed and propiolactone (with 1 percent by weight phenyl-yS-naphthylamine added as an antioxidant) at 180 ° C in air only a weight loss of 0.05% per minute.

Example 2

To a solution of 6.2 g of trioxane and 0.16 g / I-propiolactone in 20 ml of nitrobenzene are at 35 ° C given 28 mg boron trifluoride etherate (dissolved in 0.25 ml nitrobenzene). After 15 minutes the The polymerization with methanol was terminated, and the polymer which had precipitated was filtered off with suction and removed the initiator residues and the solvent treated again with methanol and dried. One obtains ao 6 g of a white powdery polymer with a melting range of 162 to 165 ° C. The thermal stable proportion is 75% after 1 hour at 190 ° C under nitrogen.

Example 3

To a solution of 6.2 g of trioxane and 0.62 g of ytf-propiolactone in 20 ml of nitrobenzene are at 35 ° C given 56 mg boron trifluoride etherate (dissolved in 0.5 ml nitrobenzene). After 25 minutes the The polymerization was terminated with methanol and the polymer was worked up as in Example 2. Man receives 5.9 g of a white polymer, the thermally stable portion of which after 1 hour at 190.degree under nitrogen is 98.1%.

Claims (1)

Claim: Process for the preparation of copolymers of trioxane by polymerizing anhydrous Trioxane with an oxygen-containing compound by means of ionic catalysts, if appropriate in inert solvents, characterized in that as oxygen-containing compound ß-propiolactone is used. Considered publications:
British Patent No. 796,863. 509 537/475 3. 65 © Bundesdruckerei Berlin