JPS5848565B2 - Production method of trioxane copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The copolymerization of trioxane with certain cyclic ethers or cyclic acetals, optionally followed by removal of unstable moieties, provides thermal products with excellent thermal stability and valuable mechanical properties. It is known that plastically processed polymers can be obtained (e.g. U.S. Pat. No. 3,027,355).
2 and 3103499).

Furthermore, 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 cooled to a temperature below the melting point at the same time as the onset of cloudiness. It is also known to obtain copolymers with increased molecular weight and improved flow properties by rewarming and cooling (see US Pat. Nos. 3,337,507 and 3,513,128).

Similarly, the homogeneous mixture of molten trioxane and catalyst is rapidly cooled to solidify before starting the polymerization, followed by 2
It is known that polymerization can be carried out in a solid state by heating at a temperature of 5 to 62°C (see US Pat. No. 3,463,757).

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

For example, in the process 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
It is usually unavoidable when the temperature is 0 to 90°C or higher, especially 100°C or higher.

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

The presence of a prepolymer is an essential prerequisite in the copolymerization according to US Pat. No. 3,337,507.

The mixture of trioxane, comonomer and catalyst is maintained at a temperature above its melting point until the appearance of a first cloudiness, which indicates the end of the initial polymerization period and the beginning of the actual polymerization, or directly. Initial polymers prepared in separate operating steps are charged.

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

Otherwise the yield is very low.

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

The formation of an initial polymer is also essential for the process according to US Pat. No. 3,513,128.

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 take shape.

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

This method requires proper confirmation of the end of the incubation period, indicated by the onset of cloudiness in the polymerization mixture, and if this is not possible and immediate cooling is not carried out, an exothermic polymerization reaction, which often begins almost instantaneously, proceeds. It has its drawbacks.

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

Otherwise, the turbidity point cannot be recognized visually.

According to the method described in US Pat. No. 3,463,757, the homopolymerization of trioxane is carried out 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 method for preparing trioxane copolymers by polymerizing 99.9 to 90% by weight of trioxane and 0.1 to 10% by weight of cyclic acetal in the presence of a cationically active catalyst, which comprises trioxane, The cyclic acetal and the catalyst are rapidly and homogeneously mixed at a temperature of 62 to 115°C, the resulting liquid mixture is subsequently immediately solidified by cooling before the appearance of turbidity, and then the mixture is mixed while maintaining a solid solidified state. During the production of trioxane copolymers by heating to a temperature of approximately 62° C. to 130° C. and after-treatment by known methods, solidification of the liquid mixture is carried out in a double screw extruder (Doppel-schnec-kene).
This method is characterized in that it is carried out in

The present invention further provides polymerization of 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 acetal and catalyst are heated at 62-115°C. The raw liquid mixture is then immediately solidified by cooling in a double-screw extruder before the appearance of cloudiness, and then while retaining the solid coagulated state of the mixture, the raw liquid mixture is rapidly and homogeneously mixed at a temperature of about 6. It relates to a molding mixture of a poly(oxymethylene) substrate consisting essentially of a copolymer obtained by heating to a temperature of ~130[deg.] C. and finally working up in a known manner.

The process according to the invention is preferably carried out using purified trioxane.

Its purification 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 should be less than 100 ppIl1, preferably less than 5 Q ppm, and the trioxane should 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 cyclic 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. Formal is suitable.

Those which may be used particularly advantageously are cyclic formals of the formula: in which R and R' are the same or different and are each 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.

An example of a cyclic acecure is 1,3-dioxolane 1
,3-dioxane 1,3-dioxepane 1,3-dioquincane, 1,3-dioquinnan, 1,3.6-t-
Mention may be made of quinquan, 4-methyl-1,3-dioxolane and 4-phenyl-1,3-dioxolane.

The amount of trioxane used is generally 99.9~? 0,
Preferably it is 99.5-95% by weight, while cyclic acecur is used in an amount of 0.1-10, preferably 0.5-5% by weight.

Particularly preferred is a mixture consisting of 99-97% by weight of trioxane and 1-3% by weight of cyclic acecure.

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, one particularly uses formaldehyde dialkyl acecules having 3 to 9, preferably 3 to 5 carbon atoms, such as formaldehyde dimethyl acecul, monoethyl acetal, dipropyl acetal and -dibutyl acetal, 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.

Cation-active catalysts include (1) protic acids, such as perchloroic acid, (2) esters of protic acids, especially esters of perchloric acid and lower aliphatic alcohols, such as tertiary butyl berchloric acid, (3) protic acids. (4)
Lewis acids Special 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 antimony, 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, triethyloxonium- Tetrafluoroborate, trimethyloxonium hexafluorophosphate, triphenylmethylhexafluoroarzenate, acetyltetrafluoroborate, acetylhexafluorophosphate and acetylhexafluoroarzenate are used. .

The amount of catalyst used in the process according to the invention depends in particular on the strength of the action.

Generally 0.1 to 20% of the total amount of monomers to be polymerized
0.00, especially 0.2 to 500 weight.

A good catalyst, such as boron trifluoride, has a molecular weight of 10 to 150, preferably 20 to 1, based on the total amount of monomers to be polymerized.
It is best to use a weight of 00p.

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

Very strongly acting catalysts such as perchloric acid have a
10, preferably in an amount of 0.3 to 5 ppm.

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

If the polymerization mixture is completely solidified by cooling for one hour before the appearance of cloudiness and is polymerized in the solid phase during heating for one hour to the polymerization temperature, the amount of catalyst has been determined exactly one hour.

It is preferable to use the general 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.

Suitable solvents are in particular 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 1:10,000,
Preferably it is 1:10 to 1:100.

Catalysts that act very strongly have a ratio of 1:5000 to 1:200
Preferably, it is diluted at a ratio of 0.00.

The polymerization method according to the invention is carried out under an inert gas atmosphere.
Advantageously, it is carried out with exclusion of moisture.

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

In principle, a device for carrying out the method of the invention is divided into a number of heating or cooling sections.
All double-screw extruders are suitable, with the screws rotating in the same or opposite directions conveying the solid material.

In particular, a double screw extruder with a pair of self-cleaning screws is used.

The number of revolutions of the screw is generally 5 to 80 times per minute, preferably 10 to 50 times per minute.

The method according to the present invention 1 has a length of 10 to 65D (D one diameter),
It is advantageous to carry out the process in a double screw extruder, preferably from 12 to 45 D, which has essentially three sections: a mixing zone, a cooling zone and a polymerization zone.

The mixing zone has a length of 1-15D1, preferably l to IOD, which is 62 to 115°C1, preferably 62 to
It is heated to a temperature of 80°C.

The cooling zone has a length of 4 to 25 D1, preferably 5 to 20 D, which is +40 to -20 °C, preferably +20 to 0
It is best to maintain a temperature of 1 °C.

The polymerization zone has a length of 5-25D1, preferably 6-15D, which is 62-130°C, preferably 80-120°C.
It is heated to a temperature of 1.

Instead of one separate extruder, it is also possible to use several successively connected extruders of corresponding dimensions.

In this case, instead of the polymerization zone of a double-screw extruder, heatable conveyor belts, paddle driers or single-screw conveyors are suitable.

The residence time of the polymerization mixture in one polymerization zone is 1 to 301 minutes in total, preferably 5 to 15 minutes, depending on the temperature and the amount of catalyst.

The mixing of monomers and catalyst must be carried out 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.

Mixing nozzles, for example single-component nozzles (one s
It is better to use a ubstance nozzle).

However, the comonomer and the catalyst can also be introduced separately into one mixing zone of the extruder.

In this case, the catalyst is preferably metered at the end of the mixing zone.

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

For this reason, 1 to 60 seconds, preferably 2 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 once to a temperature below the melting point of the mixture.

However, the mixture should be heated between +40 and -20°C, preferably between +20
Rapid cooling to a temperature of 0.8C is advantageous.

In order to remove unstable moieties, the copolymer obtained from Invention 1 is subjected to controlled partial decomposition, either thermally or hydrolytically, to generate primary alcohol end groups (
For example, US Pat. No. 3,103,499
No. 3, 2 1 9, 6 2 3 references.

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

To prepare the molding mixture according to the invention, the trioxane copolymer is 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.

As heat stabilizers, in particular polyamides, amines of polybasic carboxylic acids, amidines such as dicyandiamide, hydrazine, urea, poly(N-vinyl lactams) and aliphatic preferably hydroxyl-containing carbon atoms having from 2 to 20 carbon atoms are used. Suitable are alkaline salts of di- or tribasic carboxylic acids, such as calcium stearates, calcium lysinolate, calcium citrate and calcium lactate, and as oxidation stabilizers bisphenol compounds, such as bis(2- hydroxy-3-tertiary butyl-5-methyl-phenyl) monomethane and monobasic 4-hydroxyphenylalkanoic acid having 7 to 13 carbon atoms and 2 to
Diesters with diols having 6 carbon atoms can be used.

α-Hydroxybenzophenone and benzo}IJ azole derivatives are used as light stabilizers.

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.

Certain mixtures according to the invention may be mechanically comminuted, such as by shredding or grinding, into granules, slices, flocs or powders.

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 bars,
It is suitable for the production of molded bodies such as plates, films, belts and tubes, and household products, such as dishes, cups, and dimensionally stable, fixed-size mechanical parts, such as casings, gears, shaft parts and steering elements.

Example 1 The method according to the invention was applied to a double-screw extruder manufactured by Leistritz, in which the screw moved one turn in the opposite direction (type designation: LS).
M3 0/3 4).

The length of the working part is 1 7D (ID = 34 width; the mixing zone has a length of 3D, the cooling zone is 7D, and the polymerization zone is 7D)
is the length of

The trioxane thus purified is used by heating at reflux over 4,4'-diamino'-dicyclohexylmethane and calcium hydride under nitrogen for several hours and fractionally distilling.

The dioxolane and methylal used were each heated at reflux over lithium aluminum hydride under nitrogen for a number of hours.
Purified by fractional distillation.

A mixture of the monomers 1,3,5-trioxane and 1,3 dioxolane and methylal as regulator was passed through a nozzle with a 1.5 mm wide opening into an extruder at 1.5D.
Send one part.

A solution containing 1 part boron trifluoride-di-n-butyl etherate in anhydrous cyclohexane (weight ratio 1:40) was added to 0. 5
The 3D section is dispensed through a nozzle with a mm wide opening.

After the polymerization mixture has passed through the cooling zone and the polymerization zone, a powdered raw material is formed, which collects in a vessel at a temperature of 10° C. under a nitrogen atmosphere (crude polymer).

4 kg of the obtained polymer was placed in an autoclave at 0.5 kg. 1
Suspend one portion in a ethanol/one mixture (weight ratio 3:2) containing 1% by weight of triethylamine.

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

After cooling down gradually to room temperature, the polymer is filtered off with suction, washed once with methanol and dried under nitrogen at a temperature of 70 DEG C. in a fluidized bed dryer.

(Polymer after pyrolysis). This polymer is now mixed with 0.1% by weight of dicyandiamide and 0.5% by weight of pis(2hydroxy-3-tert-butyl-5-methyl-phenyl)-monomethane, each based on one polymer, and the resulting mixture is Granulate in a double screw extruder at a temperature of 190°C.

DIN the stabilized polymer melt index 12 or i2o
53735 and a temperature of 190°C and 2. 1 6
kg or 21.6 kg load.

Other details and test results appear from Table 1.

Example 2 Repeat example l.

However, a single screw conveyor is connected as a reactor after one double screw extruder.

The diameter of the screw is 8CrIL1 the length of the working part is 40
crfL.

Other items and test results are listed in Table 11.

Example 3 Repeat Example 1.

However, Werner &Friederer's double screw extruder (type designation Z) in which the screws move once in the same direction
SK53 variant) is used.

The length of the working part is 5 1D (ID=5:3+m
) and consists of 14 sections of the same length.

The mixing zone includes 3 sections, the cooling zone includes 6 sections,
The polymerization zone includes 5 sections.

The polymerization zone is divided into two sections heated to different temperatures.

The monomer mixture and regulator are placed at the beginning of the mixing zone and at the beginning of the extruder.
I will send this.

The catalyst solution is metered through a nozzle with an annular opening at the end of the mixing zone.

Other items and test results are summarized in Table 2I.

Comparative example A. Repeat example 2.

However, the polymerization mixture does not pass through the cooling zone.

Other matters and test results are clear from Table 1.

B. Repeat Example 3.

However, the polymerization mixture does not pass through the cooling zone.

Other items and test results are listed in Table 2.

The object of the present invention is the method described in the claims,
The embodiments include the following.

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

).

(2) Claim 1: A method according to the present invention, in which the liquid mixture is solidified by cooling it to a temperature of +40 to -20°C.

(3) Method 1 according to claim 1ζ, in which the liquid mixture is solidified in a maximum of 1 minute.

Additional related original invention patent No. 1100002 (Japanese Patent No. 5642610
The object of this publication is that when 99.9 to 90% by weight of trioxane and 0.1 to 10% by weight of cyclic acecure are polymerized in the presence of a cation-activated catalyst, trioxane, cyclic acecule and the catalyst are heated at 62 to 115°C. The resulting liquid mixture is then immediately cooled to solidify before the appearance of turbidity, and then heated to a temperature of about 62°C to 130°C while maintaining the solid solidified state of the mixture. This is a method for producing a trioxane copolymer, which is characterized by heating at one temperature and post-processing at a final stage by a known method.

In contrast, the object of the present invention is a method according to the original invention 1, characterized in that the solidification of the liquid mixture is carried out in a double screw extruder.

Therefore, the present invention achieves the same object as the original invention by making the main part of the structure of the original invention into the main part of the essential feature. Therefore, it has an additional relationship with the original invention.

Claims (1)

[Claims] 1 99.9-90 weight φ trioxane and 0.1
In polymerizing ~10 weights of cyclic acecul in the presence of a cationically active catalyst, the trioxane, cyclic acetal and catalyst are rapidly and homogeneously mixed at a temperature of 62 to 115°C, and the resulting liquid mixture is immediately turbid. solidification by cooling before emergence and then warming the mixture to a temperature of about 62° C. to 130° C. while maintaining a solid solidified state;
A process for producing trioxane copolymers by post-treatment in a known manner, characterized in that the solidification of the shell mixture is carried out in a double-screw extruder.