JPH0559255A - Preparation of acetal polymer composition - Google Patents

Abstract

PURPOSE:To obtain the title compsn. excellent in heat stability in a simplified and efficient manner without the necessity for the inactivation and washing off of a polymn. catalyst by adding an ion adsorbent to an acetal polymer without causing the inactivation of the polymn. catalyst after the preparation of the polymer and mixing them in a molten state. CONSTITUTION:Formaldehyde or its cyclic oligomer as the main monomer is (co)polymerized in the presence of a cationically active polymn. catalyst to prepare an acetal polymer, to which is then added 0.001-0.01wt.% at least one member selected from among ion adsorbents contg. at least one alkali (earth) metal oxide and at least two oxides selected from among oxides of trivalent and tetravalent elements, and ion adsorbents of the formula (wherein M1 is an alkaline earth metal; M2 is a trivalent metal; A<n-> is an n-valent anion; x is defined by 0<x<=0.5; and m is a positive figure). They are then mixed in a molten state at a temp. of the m.p. of the polymer to 270 deg.C to obtain the title compsn.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is a method for producing a high-quality acetal polymer composition having excellent thermal stability. More specifically, the present invention produces an acetal polymer or an acetal copolymer in the presence of a cationically active polymerization catalyst, deactivates the polymerization catalyst of the crude polymer taken out from the polymerization reactor, and heat-stabilizes it without washing. An acetal resin composition having excellent properties and a method for producing the same.

[0002]

2. Description of the Related Art An acetal polymer or a copolymer is converted into a cationically active polymerization catalyst by polymerization using formaldehyde or a cyclic oligomer thereof as a main monomer, or by copolymerization with a comonomer copolymerizable with these main monomers. Obtaining using is known, and various methods are known. Among them, the bulk polymerization using substantially no solvent or the quasi-bulk polymerization using 20% or less of the solvent is an industrially desirable method. Further, the crude polymer of the acetal polymer or acetal copolymer obtained by the polymerization needs to deactivate the polymerization catalyst in order to prevent depolymerization.

Conventionally, as a method for deactivating a polymerization catalyst, there has been proposed a method for deactivating a polymerization catalyst in a solution containing a basic neutralizing agent or in an organic solvent. As the basic neutralizing agent, for example, JP-A-58-34819 proposes a method using triethylamine, tributylamine, and calcium hydroxide. However, using a large amount of the solvent of the deactivating agent equal to or more than the weight of the polymer requires separation of the solvent from the polymer and recovery of the solvent, which makes the deactivation process very complicated. However, it is difficult to say that the method is industrially advantageous.

Further, as a solid deactivator, JP-A-63-2
Japanese Patent No. 7519 proposes a method using a metal sulfite. However, the thermal stability of the polymer obtained by deactivating the polymerization catalyst using these solid deactivators is not satisfactory.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides an acetal polymer and an acetal copolymer having excellent thermal stability,
It is intended to provide a method for obtaining a catalyst without requiring deactivation and washing.

[0006]

The method for producing an acetal polymer of the present invention is characterized in that a cationically active polymerization catalyst is used to polymerize formaldehyde or a cyclic oligomer thereof as a main monomer or copolymerize with these main monomers. (1) at least one selected from the group consisting of alkali metal oxides and alkaline earth metal oxides, which is produced by copolymerizing an acetal polymer by copolymerization with a comonomer and does not deactivate the polymerization catalyst after the polymerization. Ion oxide, and an ion adsorbent containing as a main component two or more oxides of at least one oxide selected from oxides of trivalent and tetravalent elements, and (2) general formula (I) M _{1 1-x} M _2x (OH) _{2 An} ^- _{X / n} · mH ₂ O (I) (In the formula, M ₁ represents at least one divalent metal selected from alkaline earth metals, and M ₂ Is 3 Represents a metal, A ^n-
Represents an n-valent anion. Further, x is 0 <x ≦ 0.5, and m is a positive number. ) At least one selected from the ion adsorbents represented by the formula (1) is added in an amount of 0.001% by weight or more and 0.01% by weight or less, and melt-mixed within a temperature range of the melting point of the polymer to 270 ° C. or less. is there.

The polymerization method in the present invention includes, for example, a bulk polymerization method which uses substantially no solvent, and a quasi-bulk polymerization method which uses, for example, 20% or less of a solvent with respect to a monomer. Furthermore, for example, a melt polymerization method in which polymerization is performed in a molten state can be used in the present invention. As the main monomer in the present invention, formaldehyde or its cyclic oligomer is used. Examples of the cyclic oligomer include trioxane, which is a trimer, and tetraoxane, which is a tetramer.

The comonomer in the present invention means a compound represented by the following general formula (II).

[0009]

[Chemical 1]

[Wherein, R _{1 to} R ₄ are the same or different and represent a methylene group or an oxymethylene group substituted with a hydrogen atom, an alkyl group or a halogen, and R ₅ is a methylene group or an oxy group. Methylene group or methylene group or oxymethylene group substituted with an alkyl group or a halogenated alkyl group (in this case, p
Represents an integer of 0 to 3. ) Or the formula (II
_{I) (CH 2) q OCH} 2 - or _{(OCH 2 CH 2) q OCH} 2 -. (III) ( in this case, p is represents 1, q is an integer of 1 to 4) in Means the divalent radical shown.

The alkyl group has a carbon number of 1 to 5,
Three hydrogens may be replaced by halogen atoms, especially chlorine atoms. ] As typical examples thereof, for example, ethylene oxide, propylene oxide, 1,3-dioxolane,
1,4-butanediol formal, epichlorohydrin diglycol formal and the like can be mentioned.

The polymerization catalyst in the present invention is a cationically active catalyst such as Lewis acid, protic acid and its ester or anhydride. Examples of Lewis acids include boron, tin,
There are halides of titanium, phosphorus, arsenic and antimony, and specific examples include boron trifluoride, tin tetrachloride,
Examples thereof include titanium tetrachloride, phosphorus pentafluoride, phosphorus pentachloride, arsenic pentafluoride, antimony pentafluoride and complex compounds or salts thereof. Further, specific examples of the protonic acid, its ester or anhydride include perchloric acid, trifluoromethanesulfonic acid, perchloric acid-tertiary butyl ester, acetyl perchlorate, trimethyloxonium hexafluorophosphate and the like.

The polymerization apparatus used in the present invention may be either a batch type or a continuous type. As the batch type polymerization apparatus, a reaction vessel with a stirrer used in the general formula can be used. As the continuous polymerization device, a self-cleaning mixer such as a cokneader, a twin screw type continuous extrusion kneader, or a twin screw paddle type continuous mixer can be used. The polymerization temperature is 60 to 200 ° C., preferably 80 to 170 ° C. The polymerization time is not particularly limited, but generally 10 seconds or more and 100 minutes or less are selected.

An ion adsorbent is added to the polymer thus obtained. The ion adsorbent used in the present invention is
At least one oxide selected from alkali metal oxides and alkaline earth metal oxides and at least two oxides consisting of at least one oxide selected from oxides of trivalent and tetravalent elements. It is an ion adsorbent containing the main component.

As the alkali metal oxide, Na can be used.
₂ O, K ₂ O, etc., alkaline earth metal oxides include MgO, CaO, etc. Further, trivalent and tetravalent element oxides include Al ₂ O ₃ , SiO ₂ ,
Examples thereof include TiO ₂ . As the ion adsorbent containing at least two kinds of oxides selected from these oxides as main components, specifically, 2.5MgO · Al ₂ O ₃ · nH
₂ O, 2MgO · 6SiO ₂ · nH ₂ O, Al ₂ O ₃ ·
9SiO ₂ · nH ₂ O, Al ₂ O ₃ · Na ₂ O · 2CO
₃・ nH ₂ O, Mg _0.7 Al _0.3 O _1.15 , Mg _0.75 Al
_0.25 O _{1.125 and the} like.

Further ion adsorption used in the present invention
As a body, general (I); M_{1 1-x}M_2x(OH)₂A^n- _{X / n}・ MH₂O (I) In the above formula (I), M₁Is selected from alkaline earth metals
And at least one divalent metal,
Then, Mg and Ca can be mentioned. The above formula
In (I), M₂Is a trivalent metal, B, Al,
Ga, In, Ti, Tl, etc. are shown, and preferable examples are:
Al can be mentioned. Further, in the above formula (I)
And A^n-Is an n-valent anion, for example, C
O₃ ^2-, OH^-, HCO₃ ^-, H₂PO_Four ^-, N
O₃ ^-, I^-Salicylate ion^-, Citrate ion ^-,
Tartrate ion^-Etc. can be mentioned. With a preferred example
Then CO₃ ^2-, OH^-Can be mentioned. This
Specific examples of such a quenching agent include, for example, Mg_0.75A
l_0.25(OH)₂CO_{3 0.125}・ 0.5H₂Indicated by O
Natural hydrotalcite, Mg_4.5Al₂(OH)₁₃
CO₃・ 3.5H₂O, Mg_4.5Al ₂(OH)₁₆CO
₃・ 4H₂There is a synthetic hydrotalcite represented by O etc.
It

The amount of the ion adsorbent added in the present invention is in the range of 0.001% by weight or more and 0.01% by weight or less. It is preferably 0.005 to 0.01% by weight.
When the amount of the ion adsorbent added is less than 0.001% by weight, the adsorption of the polymerization catalyst is insufficient and depolymerization occurs. If the addition amount is 0.01% by weight or more, the object of the present invention cannot be achieved.

The particle size of the ion adsorbent used in the present invention is not particularly limited, but is 100 to improve the dispersibility.
μm or less is preferable. Further, the ion adsorbent may be surface-treated with a surface treatment agent in order to improve compatibility with the polymer, dispersibility and the like. As a surface treatment agent, 2-3
Organic acids having 0 carbon atoms and at least one —COOH group and / or alcohols (primary, secondary or tertiary alcohols) having 2 to 30 carbon atoms, and the above two, alkali metal and alkali There are metal salts composed of an earth metal, a metal selected from the group consisting of aluminum, and the like, for example, stearic acid, linoleic acid, oleic acid, lauric acid, sodium stearate, magnesium stearate, sodium oleate, etc. Can be mentioned.

Further, the ion adsorbent in the present invention is
It may be subjected to decrystallization water treatment. The decrystallization water treatment can be easily carried out, for example, by a method of treating at a temperature of about 110 ° C. to about 400 ° C. for about 1 to 40 hours in air or an atmosphere of N ₂ , He, O ₂ , CO _2, etc. .. In the continuous polymer machine, the ion adsorbent in the present invention can be added by continuously supplying it to the rear part of the main body of the polymerizer and continuously supplying it to the outlet of the polymerizer from which the polymer is discharged. Alternatively, it can be carried out by adding to the polymer discharged from the polymerization machine and mixing.

The polymer added with the ion adsorbent is melt-mixed. By this melt mixing, the polymerization catalyst is adsorbed. The melt mixing in the present invention is 270 or higher than the melting point of the polymer.
It is carried out in a temperature range of ℃ or less. Preferably above the melting point 2
Within the temperature range of 50 ° C. or less, particularly preferably the melting point or more and 22
It is a temperature range of 0 ° C. or lower. If the melt-mixing temperature is lower than the melting point, the mixture is not melt-mixed and the adsorption is insufficient. Further, when the melt mixing temperature is higher than 270 ° C., the polymer is decomposed, which is not preferable.

Examples of the melt mixing device include a single screw type continuous extrusion kneader, a co-kneader, and a twin screw type continuous extrusion kneader. The average dispersed particle diameter of the ion adsorbent in the polymer after melt mixing in the present invention is preferably 1.0 μm or less. It is particularly preferably 0.5 μm or less.
When the dispersed particle size of the ion adsorbent is 1.0 μm or more, the adsorption of the polymerization catalyst is insufficient and the polymer is decomposed, which is not preferable.

When the melt-mixed polymer has an unstable terminal hydroxyl group, the unstable portion is decomposed and removed by a conventionally known method. For example, the unstable portion is decomposed and removed by heating the polymer with a basic substance such as an aqueous triethylamine solution. This operation can be carried out in the same manner as the melt mixing operation after adding the ion adsorbent, or by the same apparatus as the melt mixing apparatus.

[0023]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. The values shown in Examples and Comparative Examples are measured as follows. Reduced viscosity: 0.5 g of a polymer was dissolved in 100 ml of p-chlorophenol containing 2% α-pinene, and the viscosity was measured at 60 ° C. using an Ostwald viscometer. ST value (thermal stability): Resin is retained in an injection molding machine (Arborg Allrounder 100, manufactured by Western Trading Co., Ltd.) with a cylinder temperature of 230 ° C.
When a molded piece of × 2 × 3 × 120 mm was molded, the limit residence time (minute) at which silver streak occurred on 2/3 of the surface of the molded piece was defined as the ST value. Average dispersed particle size; transmission electron microscope (JE JE Ltd.)
M-100sx), the particle size of the ion adsorbent was measured by enlarging the particle size by 10,000 times.

[0024]

Examples 1 to 4 A 5-liter kneader having two stirring blades with a jacket capable of passing a heat medium was used.
The temperature was adjusted to ° C, and 2 kg of trioxane and 1.14 ml of methylal as a molecular weight modifier were added. First by mixing
The comonomer shown in the table was added. 50 rpm of this mixture
The resulting mixture was stirred, and 0.44 g of boron trifluoride diethyl etherate as a polymerization catalyst was added thereto to carry out polymerization. After 30 minutes, a heating medium at 30 ° C was passed to cool the contents. further,
After 1 hour, the contents were taken out and weighed, and the ion adsorbents shown in Table 1 were added at the addition amounts shown in Table 1.

This mixture was melt-mixed at a heat treatment temperature shown in Table 1 by using an ordinary vented twin-screw extruder. Furthermore, 5 parts by weight of water, 1 part by weight of triethylamine, and 0.2 parts of 2,2'-methylenebis (4-methyl-6-t-butylphenol) were added to 100 parts by weight of the obtained polymer.
Add 20 parts by weight and use a normal vented single-screw extruder to
After melt-stabilizing at 0 ° C. and 50 torr, the reduced viscosity and ST value were measured.

[0026]

Examples 5 and 6 Except for changing the heat treatment temperature after addition of the ion adsorbent to the temperature shown in Table 1, the same operation as in Examples 1 to 4 was performed.

[0027]

[Examples 7 to 13] As an ion adsorbent, Mg _0.75 Al
The same operation as in Examples 1 to 4 was performed except that the ion adsorbents shown in Table 1 were used instead of _0.25 O _1.125 .

[0028]

[Comparative Examples 1 to 4] The same operations as in Examples 1 to 4 were performed except that the addition amount of the ion adsorbent and the heat treatment temperature were changed to the conditions shown in Table 2.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

INDUSTRIAL APPLICABILITY According to the present invention, an acetal polymer composition having excellent thermal stability can be produced simply and effectively without deactivating the polymerization catalyst and washing.

[Procedure amendment]

[Submission date] October 18, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

Conventionally, as a deactivation method of the polymerization catalyst, water solution containing a basic neutralizing agent, or a method of deactivating the polymerization catalyst in an organic solvent, it has been proposed. As the basic neutralizing agent, for example, JP-A-58-34819 proposes a method using triethylamine, tributylamine, and calcium hydroxide. However, using a large amount of the solvent of the deactivating agent equal to or more than the weight of the polymer requires separation of the solvent from the polymer and recovery of the solvent, which makes the deactivation process very complicated. However, it is difficult to say that the method is industrially advantageous.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

Further ion adsorption used in the present invention
As a body,formula(I); M_{1 1-X}M_2X(OH)₂A^n- _{X / n}・ MH₂O (I) In the above formula (I), M₁Is selected from alkaline earth metals
And at least one divalent metal,
Then, Mg and Ca can be mentioned. The above formula
In (I), M₂Is a trivalent metal, B, Al,
Ga, In, Ti, Tl, etc. are shown, and preferable examples are:
Al can be mentioned. Further, in the above formula (I)
And A^n-Is an n-valent anion, for example, C
O₃ ^2-, OH^-, HCO₃ ^-, H₂PO_Four ^-, N
O₃ ^-, I^-Salicylate ion^-, Citrate ion ^-,
Tartrate ion^-Etc. can be mentioned. With a preferred example
Then CO₃ ^2-, OH^-Can be mentioned. This
UnaIon adsorbentAs a specific example of, for example, Mg
_0.75Al_0.25(OH)₂CO_{3 0.125}・ 0.5H₂At O
Natural hydrotalcite shown, Mg_4.5Al₂(O
H)₁₃CO₃・ 3.5H₂O, Mg_{Four. Five}Al₂(OH)
₁₆CO₃・ 4H₂Synthetic hydrotalc represented by O etc.
There is

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

[0029]

[Table 2]

Claims (1)

[Claims] 1. An acetal polymer is produced by using a cationically active polymerization catalyst and polymerizing formaldehyde or a cyclic oligomer thereof as a main monomer or by copolymerizing with a comonomer copolymerizable with these main monomers, and after the polymerization, The polymer is selected from (1) at least one oxide selected from alkali metal oxides and alkaline earth metal oxides and oxides of trivalent and tetravalent elements without deactivating the polymerization catalyst. An ion adsorbent containing two or more kinds of oxides as main components, and (2) M _{1 1-x} M _2x (OH) _{2 An} ^- _{x / n.} MH ₂ O (I) (In the formula, 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. Further, x is 0 <x ≦ 0.5, and m is a positive number. ) At least one selected from the ion adsorbents represented by the formula (1) is added in an amount of 0.001% by weight or more and 0.01% by weight or less, and the mixture is melt-mixed in the temperature range of the melting point of the polymer to 270 ° C. or less. A method for producing a characteristic acetal polymer.