JPS5848564B2 - Production method of trioxane copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Copolymerization of trioxane with certain cyclic ethers or cyclic acetals, with subsequent removal of unstable parts from case I, has excellent thermal stability and valuable mechanical properties. It is known that thermoplastically processable polymers can be obtained (e.g. U.S. Pat.
27, 35 No. 2 and No. 3,103,499)
.

Further, a homogeneous liquid mixture consisting of trioxane, a comonomer or prepolymer, and a cationically active catalyst is maintained at a temperature above the melting point of this mixture, and is rapidly heated to a temperature below the melting point at the same time as the onset of turbidity. It is also known to obtain copolymers with increased molecular weight and improved flow properties by cooling and then rewarming and cooling (U.S. Pat. 3 3 7, 5 0 7
(See No. 3, 5 1 3, 1 2 8).

Similarly, a homogeneous mixture of molten trioxane and catalyst is quickly sifted to solidify it before the start of polymerization, and then heated at a temperature of 25 to 62°C. (See US Pat. No. 3,463,757).

However, the trioxane copolymerization method described above has various drawbacks.

For example, in process 1 according to US Pat. No. 3,027,352, weight loss occurs due to volatilization of monomer and formaldehyde during the polymerization reaction.

This loss is due to the fact that during the exothermic polymerization phase the temperature in the polymerized product is approximately 8
When the temperature is 0 to 90°C or higher, especially 100°C or higher, this cannot usually be avoided.

In this case, the loss of monomer is up to about 20% by weight.

Co-duplication according to U.S. Patent No. 3,3337,507? In this case, the presence of an initial polymer is an essential prerequisite.

The mixture of trioxane, comonomer and catalyst is maintained at a temperature above its melting point until a first turbidity appears, which turbidity indicates the end of the initial polymerization period and the beginning of the actual polymerization, or directly. is charged with the initial polymer produced in a separate operating step.

Only when these prerequisites are satisfied can the charge mixture be cooled.

Otherwise the yield will be much lower.

The necessity of carrying out multiple liquid-solid phase transitions in order to obtain the best yields must be considered as a further disadvantage of the process described above.

U.S. Patent No. 3,5 1 3,1. The formation of an initial polymer is also essential for the method described in No. 2, No. 8, No. 1.

It consists of trioxane, a comonomer and a catalyst,
This is because the initially liquid mixture must be rapidly cooled as soon as turbidity appears.

Only at this point does the polymer form.

That is, the actual polymerization finally begins at this point.

This method requires accurate confirmation of the end of the incubation period, indicated by the onset of turbidity of the polymerization mixture, and this is not possible.
If immediate cooling is not carried out, it has the disadvantage that exothermic polymerization reactions proceed, often starting almost instantaneously.

Furthermore, this method can only be carried out in equipment made of transparent materials.

Otherwise, the opacity point cannot be recognized by visual acuity.

According to the method described in US Pat. No. 3,463,757, trioxane is homopolymerized in the solid phase.

This method is disadvantageous because it requires many hours of polymerization time and, moreover, only low yields are obtained.

The object of the present invention is a process for preparing trioxane copolymers by monopolymerizing 9969-90% by weight of trioxane and 0.1-10% by weight of cyclic acetals in the presence of a cationically active catalyst. The acetal and the catalyst are quickly and homogeneously mixed at a temperature of 62 to 115°C, the resulting liquid mixture is then immediately solidified by cooling before the appearance of turbidity, and then the mixture is brought to a solid solidified state. During the production of trioxane copolymers, the liquid mixture is heated to a temperature of about 628° C. to 130° C. while being maintained and then worked up by known methods. This method is characterized by solidification.

The present invention further comprises polymerizing 99.9-90% by weight of trioxane and 0.1-10% by weight of cyclic acetal in the presence of a cationically active catalyst, wherein the trioxane, cyclic acecule and catalyst are combined at a temperature of 62-115°C. The resulting liquid mixture is then immediately solidified by cooling on a roller before the appearance of turbidity, and then, while maintaining the solid solidified state of the mixture, about A molding mixture of poly(oxymethylene) substrate consisting essentially of the copolymer thus obtained is prepared by heating to a temperature of 62 DEG to 130 DEG C. and finally post-treating by a known method. related.

The process according to the invention is preferably carried out using purified trioxane, the purification of which is usually carried out by distillation or crystallization.

The purity of trioxane should be at least 99.5%, preferably at least 99.9%.

The content of water and/or formic acid is less than 100, preferably 5
0 pI) Ill and the trioxane must be virtually free of basic substances, such as amines.

As cyclic acetals used within the scope of the invention are in particular 5- to 11-, preferably 5- to 8-membered ring formals, which are different from trioxane.

In particular α,ω-diols having 2 to 8, preferably 2 to 4 carbon atoms, the carbon chain of which can be interrupted by at least one oxygen atom every two carbon atoms. A cyclic formal is suitable.

Particularly advantageous are cyclic formals of the following formula: In the above formula, R and R' are the same or different, and each represents a hydrogen atom,
means a phenyl residue or an aliphatic alkyl residue having 1 to 5, preferably 1, 2 or 3 carbon atoms, where X is 1
-7, preferably an integer from 1 to 5, y is zero or X is 1 and y is 1, 2 or 3.

Examples of cyclic acecures include 1,3-dioxolane, ■
,3-dioxane, 1,3-dioxepane, 1,3-dioquincane, ■,3-dioxonane, 1,3,6-t-
Mention may be made of rioxocane, 4-methyl-1,3-dioxolane and 4-phenyl-1,3-dioxolane.

? The amount of trioxane used is generally 1 99.9 to 90
, preferably 99.5 to 95% by weight, while cyclic acetals are used in amounts of 0.1 to 10, preferably 0.5 to 5% by weight.

Particularly preferred are mixtures consisting of 99-97% by weight trioxane and 1-3% by weight cyclic acetal.

In order to produce polymers with specific molecular weight ranges, 1.
It is advantageous to carry out the polymerization in the presence of regulators.

For this purpose, particular formaldehyde dialkyl acecules having 1 to 3 to 9, preferably 3 to 5 carbon atoms, such as formaldehyde dimethyl acecul, monodiethyl acecul, monodipropyl acecul and dibutyl acetal, are used. and lower aliphatic alcohols, preferably alkanols having 1 to 4 carbon atoms, such as methanol, ethanol, propanol and butanol are suitable.

Regulators are usually used in amounts of up to 1% by weight, preferably from 0.05 to 0.5% by weight, based on the total amount of monomers.

Examples of cationically active catalysts include (1) protic acids, such as perchloroic acid, (2) esters of protic acids, especially esters of perchloroic acid and lower aliphatic alcohols, such as perchloroic acid tertiary butyl ester, (3) proton Acid anhydrides, especially mixed anhydrides of perchloroic acid and lower aliphatic carboxylic acids, such as acetyl perchlorate, (4
) Lewis acids, especially halides of boron, tin, titanium, phosphorus, arsenic and antimony, such as boron trifluoride, tin tetrachloride, titanium tetrachloride, phosphorus pentachloride, phosphorus pentafluoride, arsenic pentafluoride and pentafluoride and (5) compounds such as complex compounds or salts, preferably etherates or onium salts of Lewis acids, such as boron trifluoride-diethyl etherate, boron trifluoride-di-n-butyl etherate, triethyloxoniu Mutetrafluoroborate, trimethyloxonium hexafluorophosphate, triphenyl-methyl hexafluoroarzenate, acetyl tetrafluoroborate, acetyl hexafluorophosphate and acetyl hexafluoroarzenate are used be done.

The amount of catalyst used in the process according to the invention depends, inter alia, on its active strength.

In general, for each total amount of monomers to be polymerized, o. i~
2000, preferably 0.2 to 500.

The active catalyst is preferably 10 to 1,501, preferably 20 to 1,500 per monomer of the total amount of monomers to be polymerized.
It is preferable to use it in a weight of iooppm.

In the case of compounds such as complex compounds or salts of the abovementioned catalysts, corresponding molar amounts are appropriate.

A very strong catalyst such as perchloric acid has a 0.2
It is used in an amount of ~10, preferably 0.3 to 5 times.

The most convenient amount of catalyst in each case can be easily determined with a few preliminary tests {
This can be determined.

The polymerization mixture is completely solidified by cooling before it becomes turbid.
If the polymerization is to be carried out in the solid phase upon heating to the polymerization temperature, the amount of catalyst is precisely determined.

It is generally better to use the catalyst in diluted form.

The gaseous catalyst is diluted with an inert gas, such as a rare gas such as nitrogen and argon, while the liquid or solid catalyst is dissolved in an inert solvent.

Particularly suitable solvents are aliphatic or cycloaliphatic hydrocarbons and nitrated aliphatic or aromatic hydrocarbons.

Examples include cyclohexane, methylene chloride, ethylene chloride, nitromethane and nitrobenzole.

The weight ratio of catalyst and diluent is usually 1:5 to 1:1000.
0, preferably 1:10 to 1:100.

A catalyst that acts very strongly has a ratio of 1:5000 to 1:2.
Preferably, it is diluted at a ratio of 0,000.

The polymerization process according to the invention is advantageously carried out under an inert gas atmosphere and with exclusion of moisture.

Suitable inert gases are rare gases such as argon and nitrogen.

The mixing of monomers and catalyst must be done as quickly and homogeneously as possible.

That is, it must be carried out within 5 seconds at most, preferably within 2 seconds at most.

The mixing step is carried out at a temperature above the melting point of the monomer mixture, ie at a temperature of about 62-115°C, preferably 62-80°C.

Cooling and solidification of the liquid polymerization mixture must also take place as quickly as possible.

For this reason, a short time of 0.5 to 60 seconds, preferably 1 to 15 seconds is sufficient depending on the type and amount of catalyst and the type, purity and amount of monomer.

In order to solidify the liquid polymerization mixture, it is sufficient to cool it one temperature below the melting point of the mixture.

However, the mixture should be heated between +40 and -20°C, preferably between +20
It is advantageous to sharply reduce the temperature by 10°C.

The method according to the invention consists essentially of a rotatable cooled roller on which a dosing device and a scraping device are arranged below or in parallel, and a heatable conveying device located below the roller. This is done in a different device.

The corresponding device is shown in FIG.

The dosing device 1 is preferably a mixing nozzle, for example a one-substance nozzle.
), through which the monomer mixture together with the catalyst is sprayed onto a roller 3 cooled with a cooling liquid 2.

It is advantageous to use a nozzle with a slit-shaped opening, which is arranged on the vertical line 1 of the roller and parallel to the roller axis.

If the roller width is large, many nozzles can be installed in parallel.
They can be arranged in a comb shape.

It is preferable to use a knife-like device as the scraping device 4, which is arranged so that the mixture of monomer and catalyst solidified on the roller is removed after the roller rotates at about 180 to 270°C. There is.

Below the rollers there is a conveying device 5, preferably a screw set conveyor or a badro screw.

The device described above is surrounded by a casing 61.

FIG. 2 is a cross-sectional view of the device. The rotational speed of the cooling roller is set so that the applied polymerization mixture is completely solidified before reaching the scraping device, and a layer that can be peeled off easily is formed on the roller. This is regulated.

The rotation speed is generally 1 to 20 per minute, preferably 3 to 1 per minute.
It is 0 rotation.

The layer thickness is usually between 0.3 and 5, preferably between 0.5 and 3.

The solidified mixture taken out from the rollers is transferred to a conveying device 1.
62-130℃, preferably 80-1
It can be polymerized without melting at a temperature of 20°C.

In this case, the polymerization mixture is then introduced into a polymerization apparatus which is connected to the latter in order to complete the polymerization.

Suitable such devices are, for example, heatable conveyor belts, paddle driers, kneaders or extruders, preferably double-screw extruders.

According to the conveying device and case 1ζ, the residence time of the polymerization mixture in the polymerization device is from 1 to 30 minutes in total, preferably from 5 to 15 minutes, depending on the temperature and the amount of catalyst.

In order to avoid the formation of deposits on the inner walls of the casing surrounding the cooling rollers and conveying device, this casing is heated to about 100-1300C, preferably 120-130C.
It is best to heat it to a temperature of 1.

To remove unstable moieties, the resulting copolymer is subjected to controlled partial decomposition, either thermally or hydrolytically, to generate primary alcohol end groups (e.g., as described in U.S. Pat. Specification No. 3,103,499 and No. 3,219
, 6 2 3).

This decomposition is preferably carried out under an inert gas atmosphere.

To prepare the molding mixtures according to the invention, the copolymers of trioxane are homogenized in the melt, preferably in the presence of stabilizers against the effects of heat, oxygen and light.

This step is preferably carried out in an extruder at a temperature above the melting point of the polymer.
It is carried out at temperatures up to 50°C, preferably from 180 to 210°C.

Heat stabilizers include, for example, polyamides, amines of polybasic carboxylic acids, amidines such as dicyandiamide, hydrazine, urea, poly(N-vinyllactum) and aliphatics, preferably containing 2 to 20 carbon atoms containing hydroxyl groups. Alkali salts of di- or tribasic carboxylic acids, such as calcium stearate, calcium ricinoleate, calcium citrate and calcium lactate, are suitable; as oxidative stabilizers bisphenol compounds,
For example, bis(2-hydroxy-3-tert-butyl-5-methyl-phenyl)monomethane and monobasic 4-hydroxyphenylalkanoic acid having 7 to 13 carbon atoms and 2
Diesters with diols having up to 6 carbon atoms can be used.

Suitable light stabilizers are α-hydroxybenzophenone and benzo-IJ azole derivatives.

These stabilizers are used in a total amount of 0.1 to 10, preferably 0.5 to 5% by weight, based on the total mixture.

The molding mixture according to the invention is made into granules, slices, flocs or powder by mechanical processing, for example by shredding or grinding.

It can be thermoplastically molded and processed by conventional methods such as injection molding or extrusion molding.

This can be used as work materials for semi-finished products and complete products, such as tobacco rods,
It is suitable for the production of structural bodies such as plates, films, belts and tubes, as well as household products, such as dishes, cups, and dimensionally stable, fixed-size mechanical parts, such as casings, gears, shaft parts and steering elements.

Example 1 Monomers 1,3.5-1-lioxane and 1,3-dioxolane, methylal as regulator and boron trifluoride-di-n-butyl etherate as catalyst? Mixing ratio 1:
A mixture of 49 and 1 part of cyclohexane dissolved in 1 part of cyclohexane is sprayed onto the cooling roller through a single nozzle.

This cooling roller has a diameter of 30CrIL1 working width of 50Cr
It has an IL and cooling distance of approximately 0.5 m and rotates at a speed of 6 revolutions per minute.

The mixture is sprayed through a nozzle heated to 85 DEG C. onto a roller kept at a temperature of 15 DEG C. with one part internal cooling and one part water.

The mixture solidified on the roller is peeled off by a knife I mounted parallel to the roller and at the height of the axis of rotation of the roller so that the solidified mixture reaches the knife after the roller has rotated 270°. .

The knife and roller chamber casings are heated to a temperature of 130°C.

The mixture stripped from the rollers falls into a conveyor set of screws installed below the rollers and having one wide upward opening.

One set of screw conveyor thus this mixture has a length of 20
It is conveyed to the mill through a tube with an inner diameter of 0 CrfL and an inner diameter of 10 CrfL.

The roller and screw chambers were placed under a nitrogen atmosphere.

The half-jacket shell of the screw casing and the tube are maintained at a temperature of 125-130°C.

The average residence time of the mixture in the screw is about 5 minutes.

The milled raw material is finally led to a vessel containing 1006 methanol to which 0.5 weight of monoethanolamine has been added.

The weight of the milled product is determined by weighing the difference (crude polymer).

1 volume of the methanolic suspension of the crude polymer is added with 300 l of methanol containing 0.1% by weight of monoethanolamine and placed in an autoclave, where it is heated to 70°C for 1 hour under stirring. .

Next, the crude polymer is taken in a suction oven, dried in a swirl bed dryer under nitrogen at a temperature of 70° C., and weighed (crude polymer after boiling).

Put the dried crude polymer into the autoclave again, and
00 l methanol/water mixture (weight ratio 3:2) and 4
00 ml of triethylamine in a mixture.

Rinse the autoclave with nitrogen and add the suspended liquid 1 to 1 while stirring.
Strain at 50°C and keep at this temperature for 30 minutes.

After gradually cooling to room temperature, the polymer is taken in a suction oven, washed once with methanol, and dried as described above (polymer after pyrolysis).

For each one of these polymers, o. 1% by weight of dicyandiamide and 0.5% by weight of bis(2-hydroxy-3-tertiary butyl-5-methylphenyl)methane were mixed, and the resulting mixture was passed through a double extruder with a trowel 1
Granulate at 90°C.

The melting index of the stabilized polymer is 12 or i2o is DI
N537351 therefore temperature of 190℃ and 216kg
Or a load of 21.6 kg is measured with one trowel.

The thermal stability of the stabilized polymer is evident from the weight loss that the polymer undergoes after heating in an oven under air at a temperature of 230° C. for 2 hours.

Other matters and test results are clear from the table. Example 2 Repeat Example 1.

However, instead of a screw set conveyor and a polymerization tube, 2 per minute
A paddle screw that rotates at a speed of 0.00 revolutions and a kneading machine that follows - this screw has a worm that intermittents, and the screw moves back and forth by 1 rotation.
r@)PR100) Use one.

The jacket temperature of the kneading machine was 130°C, and the average residence time of the polymerized mixture in the kneading machine was about 3 minutes.

Other items and test results are listed in the table.

Example 3 Repeat example 2.

However, the procedure is changed as shown in Table 1. The present invention is a method as described in Claim 1, but also includes the following as embodiments thereof.

(1) Claim 1: A method according to the present invention, in which the liquid mixture is sprayed once and applied onto the roller once.

(2) In the method described in the claims, cyclic (in the formula, R and " are the same or different, and each is a hydrogen atom, a phenyl residue, or an aliphatic alkyl residue having 1 to 5 carbon atoms. , X is an integer from 1 to 7, y is zero or
is 1 and y is 1, 2 or 3.

) (3) Claim 1: A method according to claim 1, wherein the liquid mixture is solidified by cooling the roller to a temperature of +40 to -20°C.

(4) In the method described in the claims, solidification is reduced to 0.
．． How to do it within 5 to 60 seconds.

Additional related original invention patent No. 1100002 (Japanese Patent Publication No. 56-4261
No. 0) is a subject of monopolymerization of 99.9 to 90% by weight of trioxane and 0.1 to 10% by weight of cyclic acecur in the presence of a cationic active catalyst. The raw liquid mixture is immediately mixed quickly and homogeneously at a temperature of about 62°C to 62°C, then immediately cooled to solidify before the appearance of turbidity. This is a method for producing a trioxane copolymer, which is characterized by heating to a temperature of 130°C and finally post-processing by a known method.

On the other hand, the object of the present invention (Claim 1) is a method according to the original invention 1, characterized in that the liquid mixture is solidified using a cooling roller.

Therefore, the present invention has the main parts of the essential elements of the original invention as its composition (the main parts of the essential elements) and achieves the same purpose as the original invention. As such, it has an additional relationship to the original invention.

A further object of the invention (claim 2) is an apparatus for carrying out the method described above, and therefore has an additional relation to the original invention.

[Brief explanation of the drawing]

1 (front view) and FIG. 2 (cross-sectional view) show an apparatus for carrying out the method according to the present invention 1, in which symbol 1 is a mixing nozzle, symbol 2 is a cooling liquid, symbol 3 is a cooling roller, and symbol 4 is a The scraping device, symbol 5 indicates the conveying device, and symbol 6 indicates the casing.

Claims (1)

[Claims] 199.9-90% by weight trioxane and 0.1-1
To polymerize 0% by weight of cyclic acecur in the presence of a cationically active catalyst, trioxane, cyclic acetal and catalyst are rapidly and homogeneously mixed at a temperature of 62-115°C, and the resulting liquid mixture is then immediately Before the appearance of turbidity, the mixture is cooled to solidify, and then the mixture is heated to a temperature of about 62°C to 130°C while maintaining the solid solidified state, and the trioxane is post-treated by a known method. When producing a copolymer, the liquid mixture is passed onto a cooling roller.
A method characterized in that the method is characterized in that the method is characterized by: 2 from the upper side (a dosing device), a rotatable cooling roller with a scraping device arranged below or in parallel, and a heatable conveying device located below the cooling roller;
Claim 11: Apparatus for carrying out the method according to claim 11.