KR20000071533A - Process for the production of oxymethylene polymer or oxymethylene copolymer - Google Patents

Abstract

According to the present invention, it is possible to provide an oxymethylene polymer which can deactivate the catalyst simply and efficiently, and does not need to remove the catalyst, and is excellent in thermal stability.

Trioxane or a mixture of trioxane and cyclic ether and / or cyclic acetal is polymerized using a cationic active catalyst, and then the deactivator of the catalyst is dissolved in an organic solvent having an SP value (solubility parameter) of 9.5 to 12.5. A method of producing an oxymethylene polymer or copolymer by terminating a polymerization reaction by adding a mixture thereof.

Description

PROCESS FOR THE PRODUCTION OF OXYMETHYLENE POLYMER OR OXYMETHYLENE COPOLYMER}

The present invention relates to a method for producing an oxymethylene polymer or copolymer comprising a step of inactivating a polymerization catalyst such as trioxane to stop the polymerization reaction. More specifically, the present invention relates to a method for producing an oxymethylene polymer or copolymer by polymerizing trioxane or the like with a cationic active catalyst and then terminating the polymerization reaction with a deactivator.

Trioxane alone or trioxane and cyclic ethers and / or cyclic acetals are polymerized using a cationic active catalyst to obtain an oxymethylene polymer or copolymer, and various methods have been proposed. Of these, bulk polymerization using no solvent or quasi-block polymerization using 20% or less of solvent relative to monomers is an industrially preferred method. Moreover, the copolymer of the oxymethylene polymer or copolymer obtained by superposition | polymerization needs to deactivate a catalyst in order to prevent depolymerization.

Various methods have been proposed conventionally regarding the deactivation method of the catalyst. For example, Japanese Laid-Open Patent Publication No. 58-34819 proposes a method of inactivating in an aqueous solution containing a basic neutralizing agent such as triethylamine, tributylamine, calcium hydroxide or the like in an organic solvent. However, using a solvent of a large amount of deactivator having the same weight or more with respect to the polymer requires the separation and solvent recovery of the solvent and the polymer, and the deactivation process is very complicated. Hard to say

Moreover, although the method of using a metal sulfite salt is proposed by Unexamined-Japanese-Patent No. 63-27519 as a solid deactivator, the thermal stability of the polymer which deactivated the catalyst using the deactivator of these solids is not satisfactory. On the other hand, Japanese Unexamined Patent Publication No. 57-80415 uses a method of using an organic solvent solution of a tertiary phosphine compound as a deactivator, and Japanese Unexamined Patent Application Publication No. Hei 8-208784 describes an organic solvent solution of a specific hindered amine compound. Although the method of using each is proposed, there is no description about SP value (solubility parameter) of these solvents at all.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for preparing an oxymethylene polymer or copolymer having excellent thermal stability by simply and efficiently inactivating a polymerization catalyst without the necessity of removing the polymerization catalyst by washing in view of such a situation. Is in.

Other objects and advantages of the present invention will become apparent from the following description.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the said subject, the present inventors discovered that superposition | polymerization can be stopped by dissolving and adding the deactivator of a polymerization catalyst to a specific organic solvent, and came to complete this invention.

That is, the above object and advantage of the present invention is to polymerize trioxane alone or a mixture of trioxane and cyclic ether and / or cyclic acetal using a cationic active catalyst, and then add a deactivator of the catalyst to carry out the polymerization reaction. In the production of the oxymethylene polymer or copolymer by stopping, the deactivator of the catalyst is dissolved and added to an organic solvent having an SP value (solubility parameter) of 9.5 to 12.5, and a method for producing the oxymethylene polymer or copolymer. to be.

According to the present invention, the deactivation of the polymerization catalyst is simplified by dissolving and adding a basic neutralizing agent or Lewis base, which has been generally used as a catalyst deactivator, in a specific organic solvent having high affinity with an oxymethylene polymer or copolymer. And it can carry out efficiently, suppresses the side reaction at the time of deactivation, and can obtain the oxymethylene polymer or copolymer excellent in thermal stability. According to the present invention, since the solvent used for dissolving the deactivator has a high affinity with the oxymethylene polymer or copolymer, the deactivator acts very efficiently, and the end group of which the active cationic type terminal which is continuously polymerized is stable It is understood that it is formed and blocked.

Embodiment of the invention

Hereinafter, the present invention will be described in detail. Examples of the polymerization method in the present invention include a bulk polymerization method and a melt polymerization method. For example, a preferable polymerization method is a bulk polymerization method using no actual solvent or a semi-block polymerization method using a solvent of 20% or less with respect to a monomer. According to these methods, polymerization is performed using a monomer in a molten state. In addition, as the polymerization proceeds, a polymer of powdered and aggregated solid can be obtained.

The raw material monomer in this invention mainly uses trioxane which is a cyclic trimer of formaldehyde, and the compound represented by following General formula (2) is preferable as cyclic ether or cyclic acetal used as a comonomer.

(Wherein R ₁ , R ₂ , R ₃ and R ₄ are the same or different and represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ₅ is a methylene group substituted with a methylene group or an oxymethylene group or an alkyl group or An oxymethylene group (n represents an integer of 0 to 3) or a divalent group represented by General Formula (3) or (4) (n is 1 and m is an integer of 1 to 4).

-(CH ₂ ) _m -O-CH _2- ‥‥‥ (3)

-(O-CH ₂ -CH ₂ ) _m -O-CH ₂ ‥‥‥ (4)

As the cyclic ether or cyclic acetal, for example, ethylene oxide, propylene oxide, 1,3-dioxolane, 1,3-dioxane, 1,3-dioxane, 1,3,5-trioxepane, 1, 3, 6-trioxokan etc. are mentioned. Especially as a comonomer, 1, 3- dioxolane is preferable. Moreover, in the method of this invention, you may use a suitable molecular weight modifier as needed for molecular weight control of an oxymethylene polymer or copolymer.

As the polymerization catalyst in the present invention, a general cationic active catalyst is used. Such cationic active catalysts include, for example, Lewis acids, that is, halides such as boron, tin, titanium, phosphorus, arsenic, and antimony, specifically boron trifluoride, tin tetrachloride, titanium tetrachloride, phosphorus pentachloride, Compounds such as phosphorus pentafluoride, arsenic pentafluoride and antimony pentafluoride and complexes or salts thereof, esters of protonic acids such as trifluoromethanesulfonic acid, perchloric acid, protonic acid, especially esters of perchloric acid with lower aliphatic alcohols, Acid anhydrides of protonic acids, in particular mixed acid anhydrides of perchloric acid and lower aliphatic carboxylic acids, or triethyleneoxonium hexafluorophosphata, triphenylmethylhexafluoroargenaart, acetylhexafluoroboraart, etc. Can be. Particularly preferred are compounds containing boron trifluoride, for example, hydrates and coordination complexes of boron trifluoride, and boron trifluoride diethyl ether teratriate and boron trifluoride, which are coordination complexes with ethers in the coordination complex compounds. Etheraeart is particularly preferred.

The polymerization apparatus used in the present invention may be either a batch type or a continuous type. As a batch polymerization apparatus, the reaction tank with a stirrer generally used can be used. As the continuous polymerization apparatus, a polymerization apparatus having a self-cleaning function that prevents rapid solidification during polymerization, strong stirring ability capable of coping with heat generation, tight temperature control, and adhesion of scale is preferable. Specifically, a continuous polymerization apparatus of trioxane, which has been proposed so far, such as a kneader, a twin-screw continuous extrusion kneader, a two-axis puddle continuous mixer, and the like can be used. Moreover, you may use combining two or more types of polymerization apparatuses.

The polymerization temperature is not particularly limited by the polymerization method, the type and amount of the catalyst used, and the like. When employ | adopting the bulk polymerization method generally used, Preferably it is 60-120 degreeC, More preferably, it is the temperature range of 60-110 degreeC. Moreover, polymerization time is also related to catalyst amount and polymerization temperature, and there is no restriction | limiting in particular, Generally, 0.25-120 minutes is selected and it is preferable to set it as 1-30 minutes especially.

After completion of the polymerization, the co-polymer is discharged from the polymerization apparatus, and then immediately mixed with the deactivating agent to deactivate the polymerization catalyst to stop the polymerization reaction. In the present invention, after the polymerization, the deactivator of the catalyst is dissolved and added to a specific organic solvent, and mixed contact with the production co-polymer to terminate the deactivation and polymerization of the catalyst.

As a deactivator used by this invention, the tertiary phosphine compound represented by following formula (1), for example,

(In formula, R <_6> , R <_7> and R <_8> is a C1-C18 hydrocarbon group, and may be same or different, respectively.)

And amine compounds.

These deactivators can be used individually or in combination of 2 or more types.

In said Formula (1), an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group etc. are mentioned as a C1-C18 hydrocarbon group of R <_6> , R <_7> and R <_8> , for example.

As a compound represented by said Formula (1), triphenyl phosphine etc. are mentioned, for example.

As said amine compound, primary, secondary, tertiary aliphatic amine, aromatic amine, heterocyclic amine, hindered amine, etc. are mentioned, for example.

Specific examples of the amine compound include ethylamine, diethylamine, triethylamine, mono-n-butylamine, di-n-butylamine, tri-n-butylamine, aniline, diphenylamine, pyridine, and piperi. Dine, morpholine and the like can be used.

Among these deactivators, tertiary phosphine compounds and tertiary amine compounds are preferred, and triphenylphosphine is most preferred.

The addition amount of the deactivator is not particularly limited as long as the catalyst is deactivated and the reaction is stopped, but is preferably 0.5 to 30 times, more preferably 1 to 20 times on a molar basis with respect to the used polymerization catalyst.

In this invention, the thing whose SP value (solubility parameter) is 9.5-12.5 is used as an organic solvent used in order to dissolve the said deactivator. If SP value is out of this range, since affinity with an oxymethylene polymer or copolymer becomes low, a deactivator will become ineffective and it is unpreferable.

Specific examples of the organic solvent having an SP value include 1,4-dioxane, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, s-butyl alcohol, isobutyl alcohol, t-butyl alcohol and n-pentyl. Alcohol, benzyl alcohol, ethyl cellosolve, ethyl carbitol, dimethyl carbonate, anisole, tetralin and the like. Especially, 1, 4- dioxane, propyl alcohol, butyl alcohol, and tetralin are preferable.

As the usage-amount of these organic solvents, Preferably it is 0.01-5 wt% with respect to a copolymer, More preferably, it is 0.01-1 wt%.

In any case, the deactivation is preferably carried out in the state of the fine granules of the copolymer. For that purpose, it is preferable to use what has a function which fully grinds a block polymer as a polymerization reaction apparatus, for example, You may add a quencher after grind | pulverizing the reactant after superposition | polymerization separately using a grinder, You may carry out grinding and stirring simultaneously in presence. In the pulverization, the particle size after pulverization was shaken with a Ro-Tap shaker using a standard body, and 100 wt% passed through a 10 mesh sieve, of which 90 wt% or more was 20 mesh. It is preferable to grind the sieve so that at least 60 wt% of the particles can pass through the sieve of 60 mesh, respectively. When pulverization is not performed to such a particle size, reaction of a deactivator and a catalyst is hard to be completed, and depolymerization may advance gradually with the remaining catalyst, and the molecular weight fall of the obtained polymer may occur.

In addition, deactivation reaction becomes like this. Preferably it is 0-130 degreeC, More preferably, it carries out at 20-130 degreeC. Too low a temperature requires time to complete the deactivation reaction, and too high a depolymerization occurs, both of which are undesirable.

In the present invention, the oxymethylene polymer or copolymer subjected to deactivation of the polymerization catalyst can be sent directly to a stabilization step in a later step. However, if further purification is required, the catalyst may be subjected to washing, separation recovery of unreacted monomers, drying, and the like after deactivation of the catalyst. If necessary, in the subsequent step, various stabilizers and lubricants may be blended, melt-kneaded and pelletized by an extruder or the like to obtain a product.

Example

Although the Example and comparative example of this invention are shown below, this invention is not limited to these. In addition, the meaning of the term in an Example and a comparative example and a measuring method are shown below.

[Continuous Polymerizer]

The two circles have a partially overlapped inner end face, the inner end face having a long diameter of 20 cm, and a pair of shafts in a long case having a jacket around each one, each of which has A continuous mixer in which a plurality of plates close to the interlocking triangles are imbedded, and the inner surface of the case and the surface of the plates close to the opposite triangle are cleaned at the tip of the plate close to the triangle.

[Melt index (MI)]

Melt index at 190 ° C, 2160 g standard load in g / 10 min. This was evaluated as a characteristic value corresponding to molecular weight. In other words, the lower the MI value, the higher the molecular weight. However, it is a value measured after adding a stabilizer to a copolymer powder, carrying out melt-stabilization process by 220 degreeC and 20 minute (s) with the laboprast mill by Toyo Seiki.

[Heating weight reduction rate]

Weight when the stabilizer (made by Ciba-Geigy Co., Ltd .: Iganox 245) 4.0 wt% is added to 2 g of co-polymer powder, it mixes well, it puts in a test tube, and it heats at 222 degreeC for 2 hours under reduced pressure 10 torr after nitrogen substitution. Reduction rate is shown.

Examples 1-9 and Comparative Examples 1-5

As a continuous polymerization apparatus, a continuous polymerizer having a similar structure connected to the aforementioned continuous polymerizer (the shaft is embedded with a plurality of blades like a screw instead of a plate close to an interlocking triangle) and a terminator mixer (second stage polymerization) An oxymethylene copolymer was produced using a structure having a structure similar to that of a group, and connected to three units in series with a continuous polymerizer in which a terminator solution was injected from the feed port portion and continuously mixed with a polymer. From the inlet of the first stage polymerizer, trioxane containing 4.4% by weight of 1,3-dioxolane and 500 ppm of methral as molecular weight modifier was continuously fed to trioxane, and at the same time diethyl boron trifluoride Copolymerization was carried out by continuously adding a solution in which etheraart was dissolved in benzene at a concentration of 5 wt% to 60 ppm as BF ₃ with respect to all monomers (trioxane + 1,3-dioxolane).

Further, a solution containing a deactivator dissolved in the solvent shown in Table 1 (corresponding to 0.5 wt% of the copolymer) from the terminator mixture was continuously supplied to stop the polymerization, thereby obtaining an oxymethylene copolymer from the outlet. . The properties of the obtained polymer are shown in Table 1. For comparison, polymers were prepared in the same manner as for other solvents. The properties of the obtained polymer are shown in Table 1.

Deactivator solution Properties of the polymer Type of deactivator Addition ratio to catalyst amount (fold molar) Type of solvent SP value MI (g / 10 min) Heating weight loss rate (wt%) Example 1 Triphenylphosphine 10 n-butyl alcohol 11.4 9.0 1.8 Example 2 Triphenylphosphine 5 n-butyl alcohol 11.4 9.1 1.9 Example 3 Triphenylphosphine 2 n-butyl alcohol 11.4 9.3 2.0 Example 4 Triphenylphosphine 5 1,4-dioxane 9.9 9.4 2.1 Example 5 Triphenylphosphine 5 Isopropyl Alcohol 11.2 9.3 2.0 Example 6 Triphenylphosphine 5 Tetralin 9.5 9.3 2.0 Example 7 Triethylamine 5 n-butyl alcohol 11.4 9.4 2.1 Example 8 Triethylamine 5 Isopropyl Alcohol 11.2 9.5 2.1 Example 9 Triethylamine 5 Tetralin 9.5 9.5 2.1 Comparative Example 1 Triphenylphosphine 5 benzene 9.2 12.5 3.0 Comparative Example 2 Triphenylphosphine 5 Cyclohexane 8.2 12.8 3.1 Comparative Example 3 Triphenylphosphine 5 ethanol 12.7 12.8 3.1 Comparative Example 4 Triethylamine 5 benzene 9.2 12.7 3.1 Comparative Example 5 Triethylamine 5 Cyclohexane 8.2 13.0 3.2

According to the stopping step of the polymerization reaction in the present invention, it is possible to simply and efficiently inactivate the polymerization catalyst, and it is not necessary to remove the polymerization catalyst by washing, thereby obtaining an oxymethylene polymer having excellent thermal stability. .

Claims (5)

Trioxane alone or a mixture of trioxane with cyclic ethers and / or cyclic acetals is polymerized using a cationic active catalyst, and then a deactivator of the catalyst is added to stop the polymerization reaction to prepare an oxymethylene polymer or copolymer. WHEREIN: The manufacturing method of the oxymethylene polymer or copolymer characterized by dissolving and adding the quencher of this catalyst to the organic solvent whose SP value (solubility parameter) is 9.5-12.5. The manufacturing method of Claim 1 whose deactivator is a tertiary phosphine compound represented by following formula (1). (In formula, R <_6> , R <_7> and R <_8> is a C1-C18 hydrocarbon group, and may be same or different, respectively.) The method according to claim 1, wherein the deactivator is an amine compound. The method according to claim 1, wherein the cationic active catalyst is boron trifluoride or a coordination compound thereof. The process according to claim 1, wherein the cyclic ether is 1,3-dioxolane.