JPH04110316A - Preparation of acetal polymer or copolymer - Google Patents

Abstract

PURPOSE:To improve thermal stability and yield by polymerizing a cyclic oligomer or a cyclic acetal of formaldehyde under specific conditions. CONSTITUTION:A monomer component comprising a cyclic oligomer or a cyclic acetal of formaldehyde is allowed to undergo bulk polymn., if necessary with a monomer copolymerizable therewith, in the presence of a polyumn. catalyst comprising a perfluoroalkylsulfonic acid (deriv.) in a molar ratio of the catalyst to the above monomer(s) of 1X10<-8>-5X10<-7> at 60-200 deg.C for 2sec to 20min under such conditions that both the water content and formic acid content in the monomer(s) are 40ppm or lower (wt. basis).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing an acetal polymer or copolymer.

[Prior Art and Problems to be Solved by the Invention] In the homopolymerization and copolymerization of formaldehyde or its cyclic oligomers, such as trioxane or tetraoxane, and the homopolymerization and copolymerization of cyclic acetals or ketals, such as 1,3-dioxolane. In some cases, cationically active catalysts can be used. Specific examples of such catalysts include:
Lewis acids, especially the halides of boron, tin, titanium, phosphorus, arsenic and antimony, such as boron trifluoride, tin tetrachloride, titanium tetrachloride, phosphorus pentachloride, phosphorous chloride, arsenic trifluoride and antimony trifluoride , and complexes or salts thereof, protic acids such as perchloric acid,
Esters of protic acids, such as perchloric acid-tertiary butyl ester, have been proposed. Among them, boron fluoride, or coordination compounds of boron fluoride and organic compounds, such as coordination compounds with ethers, are the most common polymerization or copolymerization catalysts whose main monomer is a cyclic oligomer of formaldehyde such as trioxane. It is widely used in industry.

However, most of these catalysts are not sufficient in terms of polymerization activity, and a certain amount of catalyst is required to satisfy the polymerization yield, and post-treatments such as deactivation and washing are complicated. It also affects the thermal stability of the product.

Polymerization of trioxane using perfluoroalkylsulfonic acid is disclosed in JP-A-48-29894. However, if this catalyst remains in the produced polymer, it significantly deteriorates the thermal stability of the polymer. For this reason, the amount of catalyst must be minimized, but in this case the reactivity during polymerization varies greatly. Regarding the polymerization of 1-heloxane using trifluoromethanesulfonic anhydride, Penczek et al.
kulare Chemie 172°24.3-
247 (1973)), it is a solution to slurry polymerization in cyclohexane, and the polymerization yield is not very good despite using a large amount of catalyst. Further, after polymerization, the produced polymer and the solvent must be separated and the solvent must be recovered, making the process complicated.

[Means and effects for solving the problem] The present inventors
As a result of extensive research into a polymerization method that overcomes the above-mentioned drawbacks of bulk polymerization of cyclic acecool and has stable high yields and excellent thermal stability, we have found that this catalyst can be used to remove trace amounts of water contained as an impurity in monomers. , discovered that formic acid has a great effect on polymerization reactions, and arrived at the present invention.

That is, the present invention provides a method for bulk polymerizing formaldehyde cyclic oligomers or cyclic acetals, or for bulk polymerizing these monomers as main monomers in the presence of a common polymer that can be copolymerized with these main monomers. Fluoroalkylsulfonic acid or perfluoroalkylsulfonic acid derivatives are chopped into all monomers and used at a molar ratio in the range of 1 x 10-a to sx+-o-', and the water content in all monomers is 4 oppm (
(based on weight) or less, and 40 ppm of formic acid (based on weight)
The present invention relates to a method for producing an acetal polymer or copolymer, which is characterized in that it is polymerized as follows.

By using the compound 1 having the above structure as a polymerization catalyst, it is possible to carry out the homopolymerization of cyclic acecure and the copolymerization using these as main monomers with comonomers that can be copolymerized with them, even in extremely small amounts. It has become possible to carry out the process even more easily and to obtain a high polymerization yield.

Furthermore, the catalyst of the present invention produces very little terminal pomate groups (-CuO groups) during polymerization.

Specific examples of catalysts used by the process of the invention include perfluorosulfonic acids such as trifluoromethanesulfonic acid, pentafluoroekunesulfonic acid, heptafluoropropanesulfonic acid, nonafluorobucunsulfonic acid, undecafluoropentane sulfonic acid, perfluorohebutanesulfonic acid, etc., and anhydrides thereof, such as trifluoromethanesulfonic anhydride, pentafluoroethanesulfonic anhydride, heptafluoropropanesulfonic anhydride, nonafluorobutanesulfonic anhydride, undecafluoropentanesulfonic anhydride, perfluoroheptanesulfonic anhydride, etc., and alkyl esters thereof, such as methyl trifluoromethanesulfonate, ethyl helifluoromethanesulfonate,
Methyl pentafluoroethanesulfonate, methyl heptafluoropropanesulfonate, etc., and alkylsilyl esters thereof, such as trimethylsilyl l-lifluoromethanesulfonate, triethylsilyl trifluoromethanesulfonate, and the like.

The type of catalyst used as a polymerization catalyst varies depending on its type.
In addition, the polymerization reaction can be controlled by appropriately changing the amount added, but in the present invention, the molar ratio is in the range of 1 x 10-'' to 5 x 10-7 based on the total amount of monomers to be polymerized, and is preferably is in the range of 2X10-' to 2XIO-7.If the catalyst concentration is below this, polymerization will not occur at all, and if the catalyst concentration is above this range, the polymerization reaction will be intense and the yield will deteriorate due to monomer scattering, etc. The thermal stability of the resulting polymer also becomes very poor.

The fact that polymerization or copolymerization is possible even with such a small amount of catalyst is effective in minimizing undesirable reactions such as decomposition of the main chain of the polymer and depolymerization caused by the catalyst, and also significantly reduces the post-treatment process. This allows for significant simplification.

The above-mentioned catalyst used in the present invention is preferably diluted with an inert solvent that does not have an adverse effect on the polymerization of cyclic acecure, and then added to the monomer in order to carry out the reaction uniformly. As the solvent for diluting the catalyst, any organic solvent that does not take part in the polymerization process can be used. For example, aromatic hydrocarbons such as benzene, toluene, xylene, aliphatic hydrocarbons such as n-hexane, n-hebutane, cyclohexane, halogenated hydrocarbons such as chloroform, dichloromethane,
Ethers such as diethyl ether and dioxane can be used. The concentration of these catalysts in the solvent is 0.01
~O, OOOIM is preferred. Further, in order to uniformly disperse the catalyst in the monomer, it is preferable to add the catalyst while stirring the monomer vigorously.

The main monomers to be used in the present invention include cyclic acetals such as trioxane, which is a cyclic trimer of formaldehyde, and tetraoxane, which is a tetramer, and compounds R2 (in the formula R1 , R2, R3 or R4 are the same or different and each represents a hydrogen atom, an alkyl group, or a halogen-substituted methylene group or an oxymethylene group, and R5 is a methylene group or an oxymethylene group, or an alkyl group or a halogenated alkyl group, respectively. methylene group or oxymethylene group substituted with (in this case p represents an integer of O to 3) or the formula -(CH2) o OCHa
-Mana means a divalent group represented by -(OCH2CH,), -0CH2- (in this case, p represents 1 and q represents an integer of 1 to 4). The alkyl group has 1 to 5 carbon atoms, and 1 to 3 hydrogen atoms may be substituted with halogen atoms, particularly chlorine atoms. ) For example, epichlorohydrin, ethylene oxide, 1,3-dioxolane, diethylene glycol formal, 1,4-butanediol formal, 1
, 3-dioxane, propylene oxide, etc. are representative. In particular, trioxane is a representative monomer most suitable as a raw monomer in the case of homopolymerization or copolymerization.

Although the method of the present invention is useful for homopolymerization of cyclic acetals, it is particularly useful for copolymerization using these as main monomers with other copolymerizable comonomers.

In the case of copolymerization, it is effective not only in copolymerization with at least one type of comonomer copolymerizable with a cyclic acetal, but also in multicomponent copolymerization of two or more types. This includes comonomers that produce polymers with branched or crosslinked molecules. The most common comonomer is the compound represented by (I) above.

Furthermore, cyclic esters such as .beta.-propiolactone and vinyl compounds such as styrene or acrylonitrile are also used. In addition, as a comonomer for forming a branched or linear molecular structure, alkyl-mono(or di)-glycidyl ether (or formal) such as methylglycidyl formal, ethylglycidyl formal,
Propyl glycidyl formal, butyl glycidyl formal, ethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether and bis(
1,2,6-hexanetriol) triformal and the like. Among them, trioxane is used as a raw monomer,
In the case of copolymerization using a cyclic ether or cyclic formal such as 1,3-dioxolane or 1,4-butanediol formal as a comonomer, the effectiveness of the catalyst of the present invention is particularly exhibited.

The amount of the comonomer added to the main monomer in the present invention is not particularly limited, but is preferably 0 to 200 mol%, more preferably 0 to 10 mol%.

Water contained as impurities in all the monomers used in the present invention, that is, monomers or monomer mixtures, is 40 ppm or less, preferably 10 ppm or less on a weight basis, and formic acid is 4 ppm or less, preferably 20 ppm on a weight basis.
It must be below pm. If the water content in the total monomer exceeds 40 ppm, the time from when the catalyst is added to the monomer until the polymerization system becomes cloudy (induction time) becomes long, and a large amount of catalyst is required, resulting in a decrease in the thermal stability of the polymerized polymer. Getting worse.

Similarly, when the amount of formic acid in all the monomers exceeds 40 ppm on a weight basis, the induction time becomes extremely long and a large amount of catalyst is required, which deteriorates the thermal stability of the polymerized polymer.

In addition, in the polymerization method of the present invention, it is also possible to further use a known chain transfer agent such as a low molecular weight linear acetal to adjust the degree of polymerization depending on the purpose.

Bulk polymerization using the polymerization catalyst of the present invention can be carried out batchwise, continuously,
Either method is possible, and a common method is to use monomers in a molten state and obtain solid powdery polymers as the polymerization progresses. It can be carried out using the same equipment and method as bulk polymerization. In other words, for the batch type, the reaction tank with a stirrer used in -IIQ can be used, and for the continuous type, the Cony Goo, twin-screw continuous extrusion mixer, twin-screw paddle type continuous mixer, etc. Continuous polymerization devices for trioxane and the like that have been proposed so far can be used, and two or more types of polymerization modes can also be used in combination.

The polymerization temperature is not particularly limited depending on the polymerization method, the type of polymer used, etc., but is preferably in the range of 60 to 200°C, more preferably 60 to 40°C. Further, the polymerization time is related to the amount of catalyst and is not particularly limited, but generally a polymerization time of 2 seconds or more and 20 minutes or less is selected. After a predetermined period of time has elapsed, the polymer taken out from the polymerization outlet J is usually in the form of lumps or powder, and some or all of the unreacted monomers are separated and supplied to the next step. The reaction system after polymerization is preferably mixed with ammonia, amines such as triethylamine and tri-n-butylamine, hydroxides of alkali metals and alkaline earth metals, and other known catalyst deactivators. Alternatively, it is preferable to neutralize and deactivate the polymerization catalyst by contacting and treating with a solution containing these deactivators. In this case, if the produced polymer is in the form of a large lump, it is of course preferable to crush it immediately after polymerization.

[Example] Examples of the present invention are shown below, but the present invention is not limited thereto. The terms and measurement methods used in Examples and Comparative Examples are as follows.

% or ppm, all by weight.

Polymerization yield: % (wt) of polymer obtained relative to total monomers fed Solution viscosity U reduced viscosity] p-chlorophenol containing 2% α-pinene], by dissolving 0.5 g of polymer in OOml It was measured at 60°C using an Ostwald viscometer.

Injection molding machine with thermal stability (ST value) and cylinder temperature of 230″C (Arburg All Rounder 100, manufactured by Western Trading Co., Ltd.)
The ST value was defined as the critical residence time (minutes) at which silver streaks were generated on 2/3 of the surface of the molded piece when a 220 m molded piece was molded by retaining the resin in the molded piece. The higher the ST value, the better the thermal stability of the polymer.

Examples 1 to 7 2 kg of trioxane and 1.14 m of Medilal, f2 as a molecular weight regulator, were charged into a 3° C. kneader having two Σ type agitating blades with a jacket through which a heat medium could pass. This mixture was stirred at 50 rpm. The concentrations of water and formic acid in the monomer mixture were shown in Table 1. The jacket temperature was adjusted to 80°C, and the catalyst solution shown in Table 1 was added to Table 1.
Polymerization was started by adding the catalyst to the concentration shown in .

The time from when the catalyst was added until the system became cloudy (induction period) was measured. After 20 minutes, water containing 1% triethylamine at 1° C. was added to the kneader, and after stirring for 1 hour, the contents were taken out and pulverized. The finely ground polymer was filtered, washed with acetone, and dried, and then the polymerization yield and reduced viscosity were measured. The results are shown in Table 1.

Examples 8 to 16 Examples 8 to 16 except that 1,3-dioxolane was added as a comonomer to trioxane in the amount shown in Table 1, and the catalyst solution shown in Table 1 was added to the catalyst concentration shown in Table 1. An experiment similar to 1 was conducted.

For polymers polymerized by adding 5 mol% of 1.3-dioxolane (Examples 10 to 12.14 to 16), after washing and drying, 5 parts by weight of water was added to 100 parts by weight of the obtained polymer. , 1 part by weight of triethylamine, 2,
Add 0.2 parts by weight of 2'-methylene bis-(4methyl-6-t-butylphenol) and continuously feed it to a conventional vented single-screw extruder, melt and stabilize at 1.200°C and 150 torr, then heat-resistant ST value was measured as stability.

Example 17 Example 2 except that 5 mol% of 1,4-butanediol formal was added to trioxane as a comonomer.
A similar experiment was conducted. The results are shown in Table 1.

Example 18 An experiment similar to Example 3 was conducted except that 0.3 mol% of ethylene oxide was added as a comonomer to trioxane. The results are shown in Table 1.

Example 19 Trioxane in Example 1 was replaced with 1,3-dioxolane, and trifluoromethanesulfonic acid was used as a catalyst with 1,3-dioxolane.
, 3-dioxolane was used at a molar ratio of 5 x 10-'.

Moisture in the monomer before polymerization is 9 ppm, and formic acid is 11 ppm.
It was m. As a result of the polymerization, the induction time was 53 seconds, the polymerization yield was 87%, and the reduced viscosity was 1.99.

Comparative Examples 1 to 3 5.0 mol% of 1,3-dioxolane was added to trioxane as a comonomer, the catalyst solution shown in Table 2 was added to the catalyst concentration shown in Table 2, and water was added to the monomer. The same experiment as in Example 1 was conducted except for the following. The results are shown in Table 2. Compared to Examples, the induction time was extremely long and the yield was also poor.

Comparative Examples 4 to 6 The same experiments as Comparative Examples 1 to 3 were conducted except that formic acid was used instead of water in the monomer. The results are shown in Table 2. In this case, polymerization did not proceed.

Comparative Examples 7 to 10 All polymerizations and post-treatments were carried out in the same manner as in Example 10 except for changing the amount of catalyst. When the amount of catalyst was less than the molar ratio lXl0-8 to the monomer, polymerization did not proceed; On the other hand, when the amount of catalyst was greater than the molar ratio of 5 x 10-6 to the monomer, the polymerization yield increased, but the thermal stability of the resulting polymer was extremely reduced.

Example 20 It has a cross section in which circles with an inner diameter of 50 mm partially overlap, and L/D=
Using a continuous mixing reactor consisting of 14 jacketed barrels that allow heat medium to pass through, and two rotating shafts with a number of interlocking paddles on the inside,
Hot water at 80'C was passed through the jacket, and two rotating shafts were rotated in the same direction at a speed of 78 rpm. At one end, 3
．． 8% (by weight) 1,3-dioxolane and 0.05%
% (by weight) of methylal was continuously fed at a rate of 1 kg/hour. The water content in the monomer mixture was 9 ppm, and the formic acid content was 19 ppm. At the same time, a dioxane solution of trifluoromethanesulfonic acid (0
, OOOIM) was continuously added at a rate of 56 m°C/hour to carry out copolymerization. The reaction mixture discharged from the other end was immediately poured into water containing 1% of 1-helioxymethylamine to deactivate the polymerization catalyst, and then the polymer was dried.

The polymerization yield was 90.1%, and the ST value was 81 minutes.

(The following is a blank space) ]9 [Effects of the invention As explained above, in the present invention, a high polymerization yield can be obtained, and furthermore, since the amount of catalyst used is extremely small, the thermal stability of the final product after the post-process is improved. Not only can you obtain products with excellent properties, but you can also simplify the post-treatment stabilization process.
Economically advantageous.

Claims (2)

[Claims] (1) In bulk polymerizing formaldehyde cyclic oligomers or cyclic acetals, or in bulk polymerizing these monomers as main monomers in the presence of comonomers that can be copolymerized with these main monomers, perfluoroalkyl is used as a polymerization catalyst. Sulfonic acid or perfluoroalkyl sulfonic acid derivatives are used in a molar ratio of 1 x 10^-^8 to 5 x 10^-^7 to all monomers, and the water content in all monomers is 40 ppm (by weight). A method for producing an acetal polymer or copolymer as described below, characterized by polymerizing formic acid at 40 ppm (by weight) or less. (2) Claim 1, characterized in that the main monomer is a cyclic oligomer of formaldehyde, and a cyclic acetal is used as a comonomer copolymerizable with the cyclic oligomer.
A method for producing the acetal polymer or copolymer described in .