JPS63101410A - Production of oxymethylene copolymer - Google Patents

Abstract

PURPOSE:To obtain a high-MW oxymethylene copolymer inexpensively in high yield within a short time, by premixing a cyclic ether with a polymerization catalyst of a boron trifluoride type, adding the mixture to trioxane and bulk- polymerizing it. CONSTITUTION:A cyclic ether (A) (e.g., propylene oxide or 1,3-dioxolane) is well premixed with a polymerization catalyst (B) selected from among boron trifluoride (hydrate) and a coordination compound of boron trifluoride with an oxygen or sulfur-containing organic compound (e.g., boron trifluoride diethyl etherate). The obtained mixture is added to trioxane, which is bulk-polymerized to give an oxymethylene copolymer. Since the polymerization catalyst can be activated by the cyclic ether, the polymerization time can be shortened and the polymer yield can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a novel method for producing oxymethylene copolymers.

More specifically, the present invention relates to a method for bulk polymerizing trioxane or the like using a boron trifluoride catalyst to produce a high molecular weight oxymethylene copolymer in a short time and in high yield.

<Prior art> In order to produce an oxymethylene copolymer, bulk polymerization of trioxane, etc. is disclosed in Japanese Patent Publication No. 44-5234, Japanese Patent Publication No. 47-4214!5, and Japanese Patent Publication No. 47-6.
No. 29, JP-A-51-84890, JP-A-Sho 5
3-86794, JP 55-164214, JP 56-38313, JP 57-13
This method is disclosed in Japanese Patent Application Laid-open No. 9113, Japanese Patent Application Laid-open No. 101108/1983, and the like.

<Problems to be solved by the invention> The above-mentioned Japanese Patent Publication No. 44-5234, Japanese Patent Publication No. 47-42
Publication No. 145, Japanese Patent Publication No. 47-629, Japanese Unexamined Patent Publication No. 51
-84890, Japanese Patent Application Laid-open No. 56-38313,
In the technique disclosed in JP-A-57-139113, a monomer such as trioxane and a catalyst are added at the same time, so the polymer yield is low and unsatisfactory.

Also, JP-A-53-86794, JP-A-55-16
In JP-A No. 4214 and JP-A-60-101108, since the reaction time is long, the polymer yield is relatively high.

Therefore, an object of the present invention is to bulk polymerize trioxane and the like to produce a high molecular weight oxymethylene copolymer in a short time with a high yield.

In other words, the present invention combines trioxane and a cyclic ether with boron trifluoride, boron trifluoride hydrate, boron trifluoride cord, and an organic compound containing an oxygen atom or a sulfur atom. When producing an oxymethylene copolymer by bulk polymerization in the presence of at least one polymerization catalyst selected from the group consisting of coordination compounds, a mixture of a cyclic ether and a polymerization catalyst was added to trioxane in advance. The present invention provides a method for producing an oxymethylene copolymer, characterized in that the above bulk polymerization is then carried out.

The cyclic ether used in the present invention is represented by the following general formula (I)
means a compound represented by

(However, in the formula, Y1 to ¥4 are hydrogen atoms, carbon atoms 1 to 6
represents an alkyl group and a halogen-substituted alkyl group having 1 to 6 carbon atoms, which may be the same or different.

Further, X represents a methylene or oxymethylene group, which may be substituted with an alkyl group or a halogen-substituted alkyl group, and m represents an integer of O to 3. Alternatively, X is -(CH
2) p-OCH2- or -〇-CH2(CH= ) p
-0-CH2- may be used, in which case m=1 and p is an integer from 1 to 3. ) Among the cyclic ethers represented by the above general formula (1), particularly preferred compounds include ethylene oxide, propylene oxide, 1.3-
Examples include dioxolane, 1,3-dioxane, 1,3-dioxolane, 1.3.5-) lioxepane, 1,3.6-) lioxocane, and epichlorohydrin.

The copolymerization amount of the cyclic ether of the present invention is in the range of 0.1 to 10 mol%, particularly preferably 0.2 to 6 mol%, based on trioxane, and if it is less than 0.1 mol%, the polymer yield will be low. Moreover, if it is more than 10 mol %, the polymerization time becomes longer, which is not preferable.

The polymerization catalyst in the present invention is characterized in that one or more compounds selected from the group of boron trifluoride, boron trifluoride hydrate, and coordination compounds of boron trifluoride and an organic compound having an oxygen or sulfur atom are It can be used in solid, liquid or solution form in a suitable organic solvent.

Examples of the organic compound having an oxygen or sulfur atom that forms a coordination compound with boron trifluoride include alcohol, ether, phenol, and sulfide.

Among these catalysts, coordination compounds of boron trifluoride are particularly preferred, and boron trifluoride/diethyl etherate and boron trifluoride/dibutyl etherate are particularly preferably used.

Examples of the solvent for the polymerization catalyst in the present invention include aromatic hydrocarbons such as benzene, toluene, and xylene, aliphatic hydrocarbons such as n-hexane, n-hebutane, and cyclohexane, alcohols such as methanol and ethanol, and chloroform. , dichloromethane, 1,2-dichloroethane, and ketones such as acetone and methyl ethyl ketone.

The amount of polymerization catalyst added is 0 per mole of trioxane.
．． The range is preferably from 0.000005 to 0.1 mol, particularly preferably from 0.00001 to 0.01 mol.

The method of mixing the cyclic ether and the polymerization catalyst of the present invention is not particularly limited, and examples include a method of adding the polymerization catalyst as it is to the cyclic ether and mixing with a mixing device equipped with a stirrer, and a method of adding the polymerization catalyst solution to the cyclic ether. A method such as mixing with a mixing device equipped with a stirrer can be used.

The polymerization catalyst and cyclic ether are heated at a temperature of 0 to 100°C, 3
a time of ~500 minutes, preferably a temperature of 10-90°C,
Mix for a time of 5 to 400 minutes. At temperatures below 0°C and times below 3 minutes, the effect of improving the polymerization rate is small;
At temperatures above and times above 500 minutes, the cyclic ether itself is polymerized and is not copolymerized into trioxane, which is not preferable.

The method of adding a mixture of a polymerization catalyst and a cyclic ether to trioxane is not particularly limited, but a method of adding a mixture of a liquid polymerization catalyst and a cyclic ether to molten trioxane is preferably used because the polymerization rate is high.

The bulk polymerization used in the present invention is not particularly limited by equipment, and any known equipment may be used; however, in bulk polymerization, rapid solidification and heat generation occur during polymerization, so
A self-cleaning type mixing device that has strong stirring ability and can control the reaction temperature is particularly preferably used.

The bulk polymerization temperature ranges from 50 to 140°C, especially from 60 to 140°C.
A range of 120°C is preferred. If the temperature is below 50°C, the polymerization rate will be slow because trioxane is solid, and if it is above 140°C, the resulting polymer will thermally decompose and a high molecular weight polymer will not be obtained, which is not preferable.

The oxymethylene copolymer produced according to the present invention is thermally unstable because it has an unstable terminal group, and is put into practical use after being stabilized in a stabilization step. As a method for stabilizing the oxymethylene copolymer in this case, a commonly known method can be employed.

Effect> In the case of the present invention, trioxane is presumed to be bulk polymerized by a catalyst activated by a cyclic ether, and this seems to be effective in shortening the polymerization time and improving the polymer yield.

<Examples> Next, the present invention will be described with reference to Examples and Comparative Examples. Note that the relative viscosity η' and polymer yield shown in Examples and Comparative Examples were measured as follows.

Relative viscosity ηr: p-chlorophenol 10 containing 2% α-pinene
0.5 g of polymer was dissolved in 0 ml and measured at a temperature of 60°C.

Polymer yield: 100 g of the obtained polymer was put into 200 ml of benzene, stirred for 30 minutes, passed through the mouth, and dried under vacuum at a temperature of 80°C. The weight of the dry polymer was measured and determined as the polymer yield.

Polymer yield (%) = dry polymer weight ffi (g) Example 1
~5, Comparative Example 1 A solution in which 0.315 g of boron trifluoride (diethyl Nietherer) was added to 151.3 g of 1.3-dioxolane was
Prepare the solution by stirring and mixing at 0°C for 30 minutes, 60 minutes, 120 minutes, 240 minutes, and 480 minutes, and heat it to 80°C.
Trioxane 1 in a 3 liter kneader with type stirring blades
．． 0 Kg and this mixture of 1,3-dioxolane and boron trifluoride diethyl etherate were added, and 50
Stir at rpm.

After 5 minutes, the contents were taken out and the relative viscosity ηr and polymer yield were measured. The results are shown in Table 1.

For comparison, Table 1 also shows 1,3-dioxolane 51.
3g, boron trifluoride diethyl etherate 0.315
The results of polymerization by adding 1.0 kg of lioxane to the kneader at the same time are also shown.

Pre-stirring time Relative viscosity Polymer yield Example 1 30
Minutes 1.81 97//2 60 1.82
98// 3 120 1.80 96/
/ 4 240 1.75 94 From Table 1, it is clear that the polymers produced according to the present invention have a high relative viscosity and a high yield.

Examples 6 to 7, Comparative Example 2 A solution of 51.3 g of 1.3-dioxolane and 0.315 g of boron trifluoride diethyl Nietherer was added to 6
The polymer was polymerized in the same manner as in Example 2, except that the solution was stirred and mixed at a temperature of 20°C and 160°C for 0 minutes.
The relative viscosity ηr and polymer yield were measured. The results are shown in Table 2.

For comparison, Table 2 also shows an example in which a solution stirred and mixed at a temperature of -20°C was used.

Pre-stirring temperature Relative viscosity Polymer yield ~ Example 6 40 1.80 96 From Table 2, it is clear that the polymer produced according to the present invention has a high relative viscosity and a high yield.

Examples 8-9, Comparative Examples 3-4 1.3 Solution of boron trifluoride diethyl etherate 0.315 g added to 25.1 g of 3-dioxolane, 1.3
Example 2 except that a solution obtained by adding 0.315 g of boron trifluoride diethyl etherate to 136.9 g of dioxolane was used and mixed with stirring at 40°C for 60 minutes.
Polymerization was carried out in the same manner as above, and the relative viscosity ηr and polymer yield of the obtained polymer were measured. The results are shown in Table 3.

Table 3 shows 25.1 g of 1,3-dioxolane.

An example in which 0.315 g of boron trifluoride (diethyl Nietherer) and 1.0 kg of trioxane were added at the same time (Comparative Example 3)
, 1.3-dioxolane 136.9g, boron trifluoride diethyl etherate 0.315g, trioxane 1.
An example (Comparative Example 4) in which 0 kg was added at the same time is shown for comparison.

1.3-dioxo Relative viscosity Polymer yield Run addition amount Example 8 25.1 1.84 98//
6.9 1.7 Comparative Example 3 25.1 1.38 86//41.
91° From Table 3, it is clear that the polymers produced according to the present invention have a high relative viscosity and a high yield.

Examples 10 to 12, Comparative Examples 5 to 7 1.3-dioxolane 51.3 g, boron trifluoride diethyl etherate 0.0788 g, 0°158 g, 0.
Polymerization was carried out in the same manner as in Example 2, except that a solution obtained by stirring and mixing 788 g of each solution at 40° C. for 60 minutes was used, and the relative viscosity ηr and polymer yield of the obtained polymer were measured. The results are shown in Table 4.

Table 4 shows 1.0 kg of trioxane, 51.3 g of 1,3-dioxolane, and 0.0788 g and 0.158 g of boron trifluoride diethyl etherate.

A polymer polymerized in the same manner as Comparative Example 1 by adding 0.788 g of each at the same time is also shown for comparison.

Trifluoride Relative viscosity Polymer yield Diethyl nitrate Additive Ofl Example 10 0.078B 1.86 98//11
0.1581.8798 〃67゜Comparative Example 5 0.07B8 1.38 8260.15
81.3583 7,. 4B'' - From Table 4 it is clear that the polymers produced according to the invention have high relative viscosities and high yields.

Example 13 51.3 g of 1.3-dioxolane, 0.302 g of boron trifluoride dibutyl etherate, 3 g of benzene, 35
Polymerization was carried out in the same manner as in Example 2, except that a solution that had been stirred and mixed for 120 minutes at a temperature of .degree.

Example 14 Same as Example 2 except that a solution of 31.2 g of ethylene oxide, 0.315 g of boron trifluoride diethyl etherate, and 3.15 g of benzene were stirred and mixed in nitrogen at a temperature of 20° C. for 60 minutes. A polymer having a relative viscosity ηr of 1.86 was obtained in a yield of 97%.

<Effects of the Invention> By producing an oxymethylene copolymer according to the present invention, a high-yield, high-molecular-weight oxymethylene copolymer can be obtained in a short time, making it possible to save energy in the process and economically Methylene copolymers can be produced.

Claims (1)

[Claims] Trioxane and a cyclic ether are combined with at least one polymerization catalyst selected from the group consisting of boron trifluoride, boron trifluoride hydrate, and coordination compounds of boron trifluoride and an organic compound containing an oxygen atom or a sulfur atom. An oxymethylene copolymer characterized by adding a mixture of a cyclic ether and a polymerization catalyst to trioxane in advance, and then performing bulk polymerization when producing the oxymethylene copolymer by bulk polymerization in the presence of the oxymethylene copolymer. manufacturing method.