DE2062958A1 - Process for the production of stable trioxane copolymers - Google Patents

Description

DR. ING. E. HOFFMANN · DIPL. ING. W. EITLE DR. HER. NAT. K. HOFFMANN

PATENT LAWYERS

D-800O MÖNCHEN 81ARABELLASTRASSE 4. TELEPHONE (0811) 911087 2062958

Perstorp AB, Perstorp / Sweden Process for the production of stable trioxane copolymers

The invention relates to a method of manufacturing of stable copolymers of trioxane with 1,3-dioxepanes.

A number of compounds are described in the patent literature which are suitable as monomers for copolymerization with trioxane to give polyoxymethylene. Examples of such monomers a are 1,3-dioxane, 1,3-dioxolane, ethylene oxide, epichlorohydrin, β-propiolactone and styrene.

109831/1920 -2-

All of these comonomers are used to introduce C-C bonds into the polymer for stabilization. If such a Polymer is heated, then monomeric formaldehyde is split off from the end groups. This split goes on for so long until the end group consists of a C-C bond, polygamy is very stable. At this point the cleavage of the macromolecule stops. To achieve a satisfactory stabilization of the copolymer, it is important that the C-C-Bin-. fertilize distributed in a uniform manner in the macromolecule are. Most of the comonomers known for this purpose have the disadvantage that they are not uniform in the macromolecule are distributed, resulting in an unstable copolymer. In addition, certain monomers also influence the other properties. For example, it is not uncommon for the strength properties to be insufficient are. This result often depends on the fact that the monomer reduces the crystallinity of the copolymer. However, unstable polymers are very difficult to process into attractive products because they are the finished objects often bubbles and uneven surface areas occur.

The invention therefore relates to a process for the production of stable trioxane copolymers, which is characterized is that you can use trioxane and a 1,3-dioxepane the general formula,

- 0.

, CH,

where Rl = R2 = CH ₂ C00CH-, or H and R ^ = H or CHgOCHO means copolymerized in the presence of a cationic catalyst.

109831/1920

The ratio of the amounts of trioxane and 1,3-dioxepane used can vary within wide limits, which depend on the desired properties of the copolymer. However Gewönnlieh 99 * 9 to 6o, O wt -, preferably 99.9% to 75> O wt -% trioxane used, the balance being 1,3-dioxepane is...

It is also possible to make terpolymers. For this purpose, smaller amounts of 1,3-dioxepane, e.g. 0.1 to 15 wt .- ^ used. For example, the third mono- | kidney from 1,> -dioxolane, 1,3-dioxane or ethylene oxide in quantities consist of about 35 to 0.1 wt .- ^ a.

The cationic catalyst can be made from a variety of compounds to be selected. Suitable catalysts are, for example, BF. ,, BP- diet hy lather at, BP ^ -Dibu ty lather at and SnCl ^. Of the Catalyst is suitably used in amounts from 0.001 to 1.0 wt .- ^.

It is advantageous to carry out the copolymerization at temperatures from 90 to 30 ° C, preferably from 70 to 50 ° C.

During the copolymerization, which is preferably carried out in the melt, heat is released. Therefore, a small amount of a heat absorbent such as cyclohexane is suitably added together with the monomers. The amount of cyclohexane added can be, for example, 5% by weight , based on the total amount of the monomers.

The copolymerization can also be carried out in solution. An inert solvent such as cyclohexane or benzene can be used for this purpose or ethylene chloride can be used.

_ H _ 109831/1920

The new 1, ^ - dioxepanes used according to the invention will provide the possibility in the copolymer functional Introduce groups. It is accordingly possible to use carboxy groups from the methoxycarbonylmethyl groups and hydroxy groups from the formyloxymethyl groups in the after polymerization a saponification is carried out. These carboxy or hydroxyl groups can be used in various ways crosslinking can be carried out, including e.g. a diisocyanate can be used. This type of networking is very valuable- full, as it gives the opportunity to arrive at a completely new type of polymer. Naturally, in the above-mentioned terpolymers are introduced functional groups in the same way.

The copolymers produced according to the invention are very stable and have good strength properties. they are therefore for processing in the usual forming machines very suitable, whereby good products are obtained can.

The invention is illustrated in the examples /. example 1

A steel container equipped with a stirrer for dispersing the polymer formed was placed in an oven and dried under a nitrogen stream. Then 50 g (86.5% by weight ) of purified trioxane, 7.8 g (13.5% by weight), 5,6-dimethoxycarbonylmethyl-1,5-dioxepane and 2.3 g of cyclohexane were added to the Reaction vessel given. ' The reaction vessel was placed in an oil bath, the thermostatically controlled temperature of which was 6 ° C., until the temperature had equalized. Then 0.02 g (0.03% by weight) of BF, dibutyl etherate dissolved in 0.6 g of cyclohexane was added to the reaction mixture through a rubber membrane. In this way the total amount of cyclohexane was 2.9 g ($ 5 calculated on the monomers). The poly.

109831/1920

merization was after 30 minutes by adding an ammonia containing mixture of water and methanol interrupted. The copolymer was carefully washed in methanol with stirring. Thereafter it was in a vacuum at a temperature of

Dried to constant weight at 70 C. The product obtained was white, fine-grained granules. The amount was 5 ^, 9 S ($ 95 of the total monomer amount). The inherent viscosity measured at 60 ° C. in p-chlorophenol containing 2% t < -pinene was 1.33 dl / g.

The unstable end groups were split off by treating the polymer for 150 minutes at a temperature of 150 ° C. in dimethylformamide (DMP), which contained an addition of borax. After washing in water-methanol and drying, a stable polymer was obtained with a yield of $ k% based on the untreated polymer.

The end-group stabilized copolymer was mixed with two known stabilizers. Then 0.3 wt .- ^ were 2.2 ^{t-methylenebis} (4-methyl-6-tert-butylphenol), and uses $ 0.2 cyanoguanidine. Those in an inert atmosphere for 30 minutes at 222 ° C
Wt .- ^ / minute.

The rate of decomposition measured at 222 ° C was only 0.011

Example 2

51.3 S (89 * 5 wt .- ^) of purified trioxane, 6, ο g (lo, 5 wt .- ^) 4-formyloxymethyl-1,3-ciioxepane and 2.3 S cyclohexane were in the reaction vessel of the example 1 given. The temperature was 60 ° C. The polymerization was initiated by adding 0.03 S (0.0-6% by weight ) ΒΡ -, - dibutyl etherate, dissolved in 0.6 g of cyclohexane. The polymerization was terminated after 30 minutes, as in Example 1. After working up, 53 * 3 S (93% of the total amount of monomers) of the copolymer were obtained. The viscosity was 0.81 dl / g.

109831/1920 " ⁶ "

After treatment with DMF and borax, a stable copolymer was obtained with a yield of 76%, based on the untreated polymer.

The end group-stabilized copolymer was mixed according to Example 1 with stabilizers. The rate of decomposition was 0.015 wt% / minute.

1 983 1/1920

Claims (6)

Claims Process for the production of stable trioxane copolymers, characterized in that one trioxane and a 1, J5-dioxepane with the general formula - O R-I - C - H R ₂ -CH CH - O where R ₁ = R ₀ = CH ₀ COOCH ^ or H and _{R 1 = H or CH 0} OCHO 1 d— d ■ j? J d. copolymerized in the presence of a cationic catalyst. 2. The method according to claim 1, characterized in that 99.9 to 60.0 wt .- ^ trioxane and 0.1 to 40.0 wt. % Of the 1,5-dioxepane compound is copolymerized with one another. 3 · The method of claim 1 or 2, characterized in that the polymerization at temperatures of 90 to J50 C, preferably 70 to 50 ⁰ C carries out one. 4. The method according to any one of the preceding claims, characterized in that the cationic Catalyst used in amounts of 0.001 to 1.0 wt .- ^. 5 · The method according to any one of the preceding claims, characterized in that one or more other copolymers are used. 10 9 8 3 1/19 2 0. q _ 6. The method according to claim 5, characterized in ₃ that there is used as further copolymers of 1,3-dioxolane, I, j5-dioxane and / or ethylene oxide. 10 9 8 3 1/19 2 0