JPH04114003A - Deactivation of polymerization catalyst - Google Patents

Abstract

PURPOSE:To remarkably simply and effectively deactivate a polymerization catalyst by adding a specified ion adsorbent to an acetal (co)polymer synthesized in the presence of a cationic polymerization catalyst and then carrying out heat treatment at a specified temperature. CONSTITUTION:Formaldehyde or its cyclic oligomer is initially homopolymerized or copolymerized with a monomer copolymerizable therewith in the presence of a cationic polymerization catalyst to obtain an acetal (co)polymer. An ion adsorbent composed mainly of two or more oxides selected from alkaline (earth) metal oxides, trivalent and tetravalent element oxides or another ion adsorbent of the formula (M1 is alkaline earth metal; M2 is trivalent metal; A<n-> is n valent anion; x is 0-0.5; n is positive number) is then added to the above-obtained polymer in an amount of 0.01-5wt.%. Heat treatment is subsequently carried out at the melting point of the abovementioned polymer-270 deg.C, thus carrying out the objective deactivation of the polymerization catalyst.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides a method for deactivating a polymerization catalyst for industrially advantageously obtaining a high-quality acetal polymer or acetal copolymer with excellent thermal stability. It is related to.

More specifically, the present invention involves polymerizing an acetal polymer or an acetal copolymer with a cationically active catalyst,
The present invention relates to a method for deactivating a polymerization catalyst that does not require washing in deactivating a polymerization catalyst of a crude polymer taken out from a polymerization reactor.

(Prior art) An acetal polymer or copolymer is produced by polymerization using formaldehyde or its cyclic oligomer as a main monomer, or by copolymerization with a comonomer that can be copolymerized with the main monomer thereof, using a cationically active polymerization catalyst. It is known to obtain them, and various methods are known. Among these, bulk polymerization using substantially no solvent, or bulk polymerization using 20% or less of a solvent with respect to the monomer, is an industrially desirable method. Furthermore, in order to prevent depolymerization of the acetal polymer or acecool copolymer assembly obtained by polymerization, it is necessary to deactivate the polymerization catalyst.

Conventionally, as a method for deactivating a polymerization catalyst, a method has been proposed in which the polymerization catalyst is deactivated in an aqueous solution containing a basic neutralizing agent or in an organic solvent.

As a basic neutralizing agent, for example, JP-A-58-34819
The publication proposes a method using triethylamine, tributylamine, and calcium hydroxide. but,
The disadvantage of using a large amount of deactivating solvent, which is equal to or more than the same weight as the polymer, is that it requires separation of the solvent and polymer and recovery of the solvent, making the deactivation process extremely complicated. Therefore, it is difficult to say that it is an industrially advantageous method.

Further, as a solid deactivator, JP-A-63-27519 proposes a method using a metal sulfite salt. However, the thermal stability of polymers whose polymerization catalysts have been deactivated using these solid deactivators is not satisfactory.

(Means for Solving the Problems) The present inventors have solved the above problems and have conducted intensive research on catalyst deactivation methods to obtain acetal polymers and acetal copolymers with excellent thermal stability. discovered a very simple and effective deactivation method and developed the present invention.

That is, the present invention is: An acetal polymer or copolymer is produced using a cationically active polymerization catalyst by polymerization using formaldehyde or a cyclic oligomer thereof as a main monomer, or by copolymerization with a comonomer that can be copolymerized with its raw monomer. In order to deactivate the polymerization catalyst, the polymer after polymerization is treated with: ■ an alkali metal oxide, an alkaline earth metal oxide, 3
An ionic adsorbent whose main component is at least two oxides selected from oxides of valent and tetravalent elements, or ■ General formula (I): Gate 11-11 M2X(O)l)2 A'-wyr %m
Hzo ・' (1) (However, in the formula, Machi represents at least one divalent metal selected from alkaline earth metals,
M2 represents a trivalent metal, A''- represents a zero-valent anion, and X satisfies 0<x≦0.5, and m is a positive number.

This is a method for deactivating a polymerization catalyst, in which 0.01 to 5% by weight of at least one kind selected from the ion adsorbents represented by the above is added, and heat treatment is performed at a temperature ranging from the melting point of the polymer to 270'C.

Furthermore, specific polymerization methods in the present invention include bulk polymerization, melt polymerization, and the like. For example, preferred polymerization methods include bulk polymerization methods that use substantially no solvent, or quasi-bulk polymerization methods that use 20% or less solvent based on the monomers,
This is a polymerization method in which a polymer in a molten state is polymerized to obtain a solid polymer that is turned into powder as the polymerization progresses.

The main monomer used in the present invention is formaldehyde or a cyclic oligomer thereof.

The comonomer in the present invention refers to a compound represented by the following general formula (It).

R.

R2-C-0... (II) R:l C(R3)p [However, in the formula, R1-R4 are the same or different, and are a hydrogen atom, an alkyl group, or a methylene group monosubstituted with a halogen. or an oxymethylene group, and R6 is a methylene group or an oxymethylene group, or a methylene group or an oxymethylene group substituted with each h alkyl group or a halogenated alkyl group (in this case, p represents an integer of 0 to 3).

) or the expression: %formula% (In this case, p represents 1 and q represents an integer from 1 to 4.

) means a divalent group represented by

The alkyl group has 1 to 5 carbon atoms, and 1 to 3 hydrogen atoms may be replaced by halogen atoms, especially chlorine atoms. ] Typical examples include ethylene oxide, propylene oxide, 1,3-dioxolane, 1,4-butanediol formal, epichlorohydrin diglycol formal, and the like.

The polymerization catalyst in the present invention is a cationically active catalyst such as a Lewis acid, a protonic acid, and its ester or anhydride.

Examples of Lewis acids include boron, tin, titanium, phosphorus,
There are halides of arsenic and antimony, and specific examples include boron trifluoride, tin tetrachloride, titanium tetrachloride,
Examples include phosphorus pentafluoride, phosphorus pentachloride, arsenic pentafluoride, antimony pentafluoride, and complex compounds or salts thereof. Also,
Specific examples of protonic acids, their esters or anhydrides include perchloric acid, trifluoromethanesulfonic acid,
Examples include perchloric acid tertiary butyl ester, acetyl perchlorate, trimethyloxonium hexafluorophosphate, and the like.

The polymerization apparatus used in the present invention may be either a hatch type or a continuous type. As a batch type polymerization apparatus, a reaction tank equipped with a stirrer used in the -111 type can be used. As the continuous polymerization apparatus, a self-cleaning mixer such as a co-kneader twin-screw continuous extrusion kneader or a two-wheeled paddle-type continuous mixer can be used.

Polymerization temperature is 60-200°C, preferably 60-140°C
temperature range. Further, the polymerization time is not particularly limited, but -C is selected to be from 10 seconds to 100 minutes. A deactivator for the polymerization catalyst is added to the polymer thus obtained.

Among the deactivators used in the present invention, one type is an ion adsorbent whose main component is at least two oxides selected from oxides of alkali metals, alkaline earth metals, and trivalent and tetravalent elements. Alkali metal oxides include Na, 0
Examples of alkaline earth metal oxides include MgO1CaO, and trivalent and tetravalent oxides.
As oxides of valence elements, A1. O,, SiO□, Ti
Examples include O2.

As an ion adsorbent whose main components are at least two kinds of oxides selected from these oxides, specifically 2.5M
g0-AIto, ・nHto, 2Mg0 ・6S i
ox・nHzO1A1zOs9S! Ox・nHg01A
l103 ・NatO'2Co, -nH,0, M g
o, tA 1 o, zO+, +s and the like.

Furthermore, other deactivators used in the present invention include general formula (I): M+ 1-+= Mi-(OH)z A'-, .
+wJOH+ (1) In the above formula (+), "gate" represents at least one divalent metal selected from alkaline earth metals, and preferable examples include Mg and Ca. In the above formula (1), M2 is a trivalent metal and represents B, AI, Ga, In, TiXT1, etc., and a preferable example is A1. moreover,
In the above formula (1), A'- represents an n-valent anion, such as Co, 20 H-, HCO3-, HxP O
4-, N03I-salicylic acid ion\citrate ion\tartrate ion-, and the like. Preferred examples include CO,''- and OH-.

Specific examples of such deactivators include, for example, Mg
o, ysA lo, zs (OH) t CO3゜, 1
t, natural hydrotalcite denoted by 0.5H*O, Mga, sA Iz (OH)+3cO3.3. sHz
.

There are synthetic hydrotalcites shown in

The amount of the deactivator added in the present invention is 0.0 to the polymer.
It is 1 to 5% by weight. The amount is preferably 0.01 to 1% by weight, particularly preferably 0.01 to 0.5% by weight.

If the amount added is less than 0.01% by weight, the polymerization catalyst is insufficiently deactivated and depolymerization occurs. In addition, the amount added is 5% by weight.
If this is the case, coloring will occur during molding, and the color tone of the molded product will deteriorate.

Further, the particle size of the deactivator is not particularly limited, but is preferably 100 μm or less in order to improve dispersibility. Also,
The deactivator may be surface-treated with a surface-treating agent in order to improve compatibility with the polymer, dispersibility, etc.

As surface treatment agents, organic acids having 2 to 30 carbon atoms and at least one 10-OH group and/or 2 to 3
Alcohols with 0 carbon atoms (primary, secondary or tertiary)
There are metal salts composed of the above two alcohols and a metal selected from the group consisting of alkali metals, alkaline earth metals, and aluminum, such as stearic acid,
Linoleic acid, oleic acid, lauric acid, sodium stearate, magnesium/umium stearate, sodium oleate, etc. can be suppressed.

Furthermore, the deactivator in the present invention may be subjected to membrane crystallization water treatment. Membrane crystallization water treatment is carried out, for example, at a temperature of about 110°C to about 4°C.
In air or N2, H for about 1-40 hours at a temperature of 00 °C
This can be easily carried out by a method of processing in an atmosphere of e, Ol, CO□, or the like.

The polymer to which the quencher has been added is melt mixed.

This heat treatment deactivates the polymerization catalyst. The heat treatment in the present invention is carried out at a temperature ranging from the melting point of the polymer to 270°C. Preferably the temperature range is from the melting point to 250°C, particularly preferably from the melting point to 220°C. If the heating temperature is lower than the melting point, melting and mixing will not occur, resulting in insufficient deactivation. In addition, the heat treatment temperature is 270″
If it is higher than C, decomposition of the polymer will occur, which is not preferable.

Examples of the heat treatment apparatus include a single screw continuous extrusion kneader, a co-kneader, a two-wheel screw continuous extrusion kneader, and the like.

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Note that the values shown in Examples and Comparative Examples are measured as follows.

Reduced viscosity: 0.5 g of polymer was dissolved in 100 d of p-chlorophenol containing 2% α-pinene and measured at 60'C using an Ostwald viscometer.

ST value (thermal stability): The resin was retained in an injection molding machine (Aburg All Rounder-100, manufactured by Western Trading Co., Ltd.) with a cylinder temperature of 230°C, and 1x2
When a molded piece of X3X120 was molded, the critical residence time (minutes) at which silver streaks appeared on 2/3 of the surface of the molded piece was defined as the ST value.

Examples 1 to 6 A 51-volume kneader having two stirring blades with a jacket through which a heat medium can pass was adjusted to 80°C, and 2 kg of trioxane and 1.14 ml of methylal as a molecular weight regulator were added.
- was added. The comonomers listed in Table 1 were added by mixing. This mixture was stirred at 5 Orpm, and 0.44 g of boron trifluoride diethyl etherate was added as a polymerization catalyst.
g was added to carry out polymerization. After 30 minutes, the contents were cooled by passing a heating medium at 30°C. Further, after one hour, the contents were taken out, and after measuring the weight, the deactivating agent shown in Table 1 was added in the amount shown in Table 1.

This mixture was melt-mixed using a conventional vented twin-screw extruder at the heat treatment temperatures shown in Table 1. Furthermore, with respect to 100 parts by weight of the obtained polymer, 5 parts by weight of water, 1 part by weight of triethylamine, 2,2 methylenebis(4-methyl-6
- 0.2 parts by weight of t-butylphenol) was added, and a 200″C15Qtor
After the melt was stabilized at r, the reduced viscosity and ST@ were measured.

Furthermore, after melt stabilization, the polymers were molded using a normal injection molding machine, and the coloring conditions were compared with the naked eye.

Examples 7 to 9 The same operations as in Examples 1 to 6 were performed except that the heat treatment temperature after addition of the deactivator was changed to the temperature shown in Table 1.

Examples 10 to 13 As a deactivator, Mg, , AI□(OH) + 3.
The same operations as in Examples 1 to 6 were carried out except that the deactivating agent shown in Table 1 was used instead of 3.20.

Comparative Examples 1-2 Polymerization was carried out in the same manner as in Examples 1-6. Thirty minutes after the addition of the polymerization catalyst, 100 parts by weight of water containing 1% triethylamine was added to a 51-volume Nigu, stirred for 1 hour to deactivate the catalyst, and the contents were taken out. Shattered. The finely ground polymer was filtered, washed with acetone and dried.

Furthermore, 5 parts by weight of water, 1 part by weight of triethylamine, and 0.0 parts by weight of 2°2'-methylenebis(4-methyl-6-t-butylphenol) were added to 100 parts by weight of the obtained polymer.
Add 2 parts by weight, use a normal single screw extruder with hent,
After stabilizing the melt at 00°C and 150 torr, the reduced viscosity and ST value were measured. Furthermore, after melt stabilization, the polymers were molded using a normal injection molding machine, and the coloring conditions were compared with the naked eye. The results are shown in Table 2.

Comparative Examples 3 to 5 The same operations as in Examples 1 to 6 were performed except that the amount of additive added was changed to the amount shown in Table 2.

(Effects of the Invention) The present invention provides a method for deactivating a polymerization catalyst in an acetal polymer polymerized using a cationic polymerization catalyst by heat treatment in the presence of a specific ion adsorbent, especially after washing. An acetal polymer can be obtained which can be simply and effectively deactivated without the need for oxidation, and which has excellent thermal stability.

Procedural amendment October 18, 1990

Claims (1)

[Claims] An acetal polymer or copolymer is produced by polymerization using formaldehyde or a cyclic oligomer thereof as a main monomer, or by copolymerization with a comonomer that can be copolymerized with the main monomer, using a cationically active polymerization catalyst. manufactured by
In deactivating the polymerization catalyst, (1) an alkali metal oxide, an alkaline earth metal oxide,
An ion adsorbent whose main component is at least two oxides selected from oxides of trivalent and tetravalent elements, or (2) general formula (I): M_1_(_1_-_x_) M_2_(_x_)(OH
)_2A^n^-_x_/_n・mH_2O・・(I
) (wherein, M_1 represents at least one divalent metal selected from alkaline earth metals, M_2 represents a trivalent metal, and A^n^- represents an n-valent anion.
is 0<x≦0.5, and m is a positive number. Adding 0.01 to 5% by weight of at least one kind selected from the ion adsorbents represented by
A method for deactivating a polymerization catalyst, characterized by heat treatment in a temperature range of 0°C.