JP2019073637A - Quaternary ammonium compound solution, and use thereof for inhibiting generation of volatile organic compounds from polyacetal - Google Patents

Abstract

To provide a quaternary ammonium compound solution which has a good color tone, causes only small amounts of formaldehyde, acetaldehyde and acrolein even if heat treatment such as thermofusion is performed, and is suitable for use as an agent for inhibiting volatile organic compounds from polyacetal.SOLUTION: The invention provides a solution containing a quaternary ammonium compound with a structure represented by a specific general formula whose kinematic viscosity at water temperature of 15°C is 0.4 to 10.0 mm/s.SELECTED DRAWING: None

Description

  The present invention relates to solutions containing novel quaternary ammonium compounds, and in particular to quaternary ammonium compound solutions suitable for use as inhibitors of volatile organic compound generation from polyacetals.

Polyacetal is widely used in parts of automobiles, electronic devices, electric devices, etc. because it has well-balanced mechanical properties and excellent fatigue characteristics. The polyacetal copolymer is produced by copolymerizing formaldehyde or a cyclic acetal such as trioxane, which is a cyclic trimer thereof, and either or both of a cyclic ether and a cyclic formal. However, the polyacetal copolymer obtained by such copolymerization has-(OCH2) n -OH group at a part of molecular terminals, and this terminal group is thermally unstable, so heating at the time of molding processing etc. It decomposes more easily and generates a large amount of formaldehyde, so it can not be put to practical use as it is. That is, if a large amount of formaldehyde is generated, the resin may be foamed during molding, or a line from which gaseous formaldehyde is removed may remain on the surface of the molded product, resulting in a defect such as a poor appearance. Furthermore, the generated formaldehyde is oxidized by oxygen in the molding machine to form formic acid, which promotes the main chain decomposition of the polyacetal copolymer.
In particular, from the viewpoint that formaldehyde is an objectionable substance for the human body in recent years, a material having an extremely low generation amount of formaldehyde from a product after molding is required, and a polyacetal having a small generation amount of formaldehyde has been invented.

  In recent years, in a highly demanding area such as an application in which the inside of an organism is also in contact, a material suppressed to an amount of formaldehyde generation much lower than the conventional level is required. In addition, the reduction of not only formaldehyde but also acetaldehyde and acrolein which is highly toxic to microorganisms has been required. Accordingly, there is a need for materials having extremely low amounts of acetaldehyde and acrolein as well as the above-mentioned formaldehyde.

  Since polyacetal is generally low in stability due to heat or the like, it is generally a resin composition to which a heat stabilizer or the like is added. Low generation of formaldehyde in the polyacetal itself, which is the base resin, is essential for obtaining a material with extremely low generation of formaldehyde.

After polymerization, polyacetal has formaldehyde at the unstable end. As a method of stabilizing a polyacetal copolymer (hereinafter sometimes referred to as crude polyacetal), a method of acetylating, etherifying, or urethanizing the terminal, a method of decomposing an unstable terminal, etc. are known. ing.
Among them, a method of decomposing and stabilizing the unstable end is advantageous. As a method of decomposing the unstable end, a method of heating and stabilizing a crude polyacetal copolymer in water or an organic solvent in the presence of a basic substance capable of decomposing the unstable end, crude Methods of stabilizing a polyacetal copolymer in a heated and molten state are known. The method of heating and stabilizing the crude polyacetal copolymer in water or in an organic solvent requires operations such as separation (filtration), recovery, washing, etc., while the method of stabilizing in the heat-melted state is It is the most industrially advantageous method because a directly stabilized polyacetal copolymer is obtained.
As a conventionally known heat treatment method, the crude polyacetal copolymer is unstable by heat treatment while maintaining a heterogeneous system in a medium (for example, water, water / methanol mixed solution) in which the polyacetal copolymer is not dissolved. Methods for removing such end portions are known (for example, Patent Document 1 and Patent Document 2). However, in this method, it is necessary to operate at a temperature close to the melting point of the polyacetal copolymer in order to increase the decomposition rate of the unstable end and to perform long treatment to reduce the unstable end. was there. Even if such treatment is carried out, the resulting polyacetal copolymer does not have sufficient decomposition and removal of unstable end portions, and there has also been a problem that the polyacetal copolymer tends to be colored due to long-term treatment at high temperature .

Further, Patent Document 3 discloses that the crude polyacetal copolymer is unstable by exposing the crude polyacetal copolymer to a pressure of atmospheric pressure or more at a temperature of 100 ° C. or more in a saturated vapor mixture consisting of a volatile organic solvent, a volatile base and water. A method of removing the end is disclosed. However, even with this method, removal of the unstable end was not sufficient. There is also known a method in which the crude polyacetal copolymer is heated and kept in a molten state to decompose and remove unstable end portions.
For example, Patent Document 4 discloses a method of kneading a melt copolymer on a roll mill for a certain period of time, Patent Document 5 or Patent Document 6 discloses using an extruder or the like in the presence of water, alcohol or the like or further an alkali component. A method of heating and melting, Patent Document 7 discloses a method of heating and melting a crude polyacetal copolymer and then decomposing and removing an unstable portion under reduced pressure using a special surface renewal mixer, Patent Document 8 Is a single screw extruder for melting a crude polyacetal copolymer, a reactant comprising a crude polyacetal copolymer and water and a compound which forms a hydroxide in the presence of water according to the principle of flow splitting and rearrangement And a reactive mixer comprising a static mixer having a reaction zone for decomposing the unstable portion while mixing and a vented screw extruder for devolatilization disposed immediately after the static mixer. Patent Document 9 describes a method of decomposing and removing unstable parts in a powder, or treating a powdery or powdery crude polyacetal copolymer under reduced pressure at a temperature 5 to 35 ° C. lower than the melting temperature, and then heating with an extruder. Methods for melt processing have been proposed respectively.
A considerable stabilization is possible even by a method in which these crude polyacetal copolymers are heated and kept in the molten state to decompose and remove only the thermally unstable end portions, and the polyacetal copolymers subjected to such treatment can be used practically. In addition, a thermally unstable end portion may remain, which may cause an undesirable phenomenon such as generation of mold deposit (mold deposit) in molding processing and the like. Therefore, more stable polymers are strongly desired.

In these known methods, in order to increase the decomposition rate, the above-mentioned basic physical properties, an alkali component, or a compound that produces a hydroxide in the presence of water, etc. (eg, amines widely used for this type of application, etc.) It was necessary to add to the polyacetal copolymer and to increase the addition amount. However, if the amount of addition of amines etc. is increased too much, the polymer will be colored. Furthermore, in order to reduce unstable end portions, it has been necessary to carry out treatment for a long time or a plurality of times. For this reason, not only the polyacetal copolymer after stabilization is deteriorated in color, but also the apparatus becomes large and complicated. Furthermore, there is also a problem that decomposition and removal of the unstable end of the crude polyacetal copolymer is not always sufficient.
In Patent Document 10, in order to solve these problems, as a stabilization method for obtaining a very few polyacetal copolymer with very few unstable end portions by a simple method, the heat treatment is carried out by the presence of a quaternary ammonium compound having a specific structure. It is disclosed to do below. According to this method, rapid stabilization of the thermally unstable terminal portion of the polyacetal copolymer can be realized, and various problems associated with the above-described stabilization method can be solved. It has not come to suppress generation of acetaldehyde and acrolein which are generated after heating and melting.

  Further, Patent Document 11 discloses a stabilization method mainly using a quaternary ammonium compound of polyacrylic acid as a method of improving odor characteristics while removing unstable ends. However, in this method, the odor evaluation at the substantial processing temperature has not been achieved, and a problem remains as the odor evaluation at the processing temperature or more. Moreover, since polyacrylic acid has a high boiling point and remains in the polymer, it can not be said that there is no concern about coloring in addition to the decomposition behavior at the time of heating, suppressing the generation of acetaldehyde and acrolein generated after heating and melting such as molding. It does not reach.

Japanese Patent Publication No.40-10435, Japanese Patent Publication No. 43-7553 Japanese Patent Publication No. 40-11627 Japanese Examined Patent Publication No. 39-8071 Japanese Patent Publication No. 43-1875 (corresponding to US Pat. No. 3,337,504) Japanese Patent Publication No. 44-11907 (corresponding to US Pat. No. 3,418,280) Japanese Patent Publication No. 58-11450 (corresponding to U.S. Pat. No. 4,366,305) Japanese Patent Application Laid-Open No. 58-152012 (corresponding to European Patent No. 88, 541) Japanese Patent Application Laid-Open No. 62-129311 Patent No. 3087912 Patent No. 5031196

  In the present invention, therefore, it is an object of the present invention to provide a polyacetal resin composition having high color tone, good generation of formaldehyde, acetaldehyde and acrolein even when subjected to heat treatment such as heat melting, and the like.

As a result of investigations to solve the above problems, the present inventors have found that novel quaternary ammonium compounds having a specific structure generate volatile organic substances from polyacetals after heat treatment such as heat melting. It was found to be effective in suppressing.
However, when the polyacetal was treated with this quaternary ammonium compound, it was found that there is room for improvement in the coloring of the resulting polyacetal. And as a result of earnestly examining in order to solve the problem of coloring, when this quaternary ammonium compound is used in the form of a solution having a specific dynamic viscosity, the generation suppressing effect of volatile organic substances is maintained while coloring is maintained. The inventors have found that an excellent polyacetal having no color tone can be obtained, and completed the present invention.

That is, the present invention is as follows.
[1] A quaternary solution containing a quaternary ammonium compound (A) represented by the following formula (1), wherein the kinematic viscosity at a water temperature of 15 ° C. is 0.4 to 10.0 mm ² / s Ammonium compound solution.
[(R1) _m (R2) _4-m N ⁺ ] _n X ^n- (1)
(Wherein, R 1 is each independently a C 1 to C 30 unsubstituted alkyl group or a substituted alkyl group; a C 6 to C 20 aryl group; a C 1 to C 30 unsubstituted alkyl group or a substituted alkyl An aralkyl group in which the group is substituted with at least one aryl group having 6 to 20 carbon atoms; or an aryl group having 6 to 20 carbon atoms is at least one non-substituted alkyl group having 1 to 30 carbon atoms or a substituted alkyl group An unsubstituted alkyl group and a substituted alkyl group are linear, branched or cyclic, and the substituent of the substituted alkyl group is a halogen, a hydroxyl group, an aldehyde group, a carboxyl group, an amino group. The hydrogen atom of the unsubstituted alkyl group, the aryl group, the aralkyl group, and the alkylaryl group may be substituted with a halogen.
R2 each independently represents a group represented by the following formula, which has 2 to 60 carbon atoms and 2 to 30 oxygen atoms.
-(RO) k-H (wherein R represents a substituted or unsubstituted alkyl group and k represents a natural number of 2 or more).
m and n represent an integer of 1 to 3;
X is an acid residue of a compound selected from the group consisting of a hydroxyl group or a monocarboxylic acid having 1 to 20 carbon atoms, hydrogen acid, oxo acid, an inorganic thio acid and an organic thio acid having 1 to 20 carbon atoms, And a group not containing a nitrogen atom.
[2] The quaternary ammonium compound solution according to [1], wherein X in the formula (1) is an acid residue of a monocarboxylic acid.
[3] The quaternary ammonium compound solution according to [2], wherein the monocarboxylic acid is formic acid, acetic acid or propionic acid.
[4] The quaternary ammonium compound solution according to any one of [1] to [3], which has 2 to 6 carbon atoms of R 2 in the formula (1).
[5] The quaternary ammonium compound solution according to any one of [1] to [4], which contains a quaternary ammonium compound (C) represented by the following formula (3).
[R3R4R5R6N ⁺ ] _l Y ^l- (3)
(Wherein, R 3, R 4, R 5 and R 6 are each independently an unsubstituted alkyl group having 1 to 30 carbon atoms or a substituted alkyl group; an aryl group having 6 to 20 carbon atoms; an unsubstituted group having 1 to 30 carbon atoms An alkyl group or an aralkyl group in which a substituted alkyl group is substituted with at least one aryl group having 6 to 20 carbon atoms; or an aryl group having 6 to 20 carbon atoms has at least one unsubstituted alkyl group having 1 to 30 carbon atoms Or an alkylaryl group substituted with a substituted alkyl group, wherein the unsubstituted alkyl group and the substituted alkyl group are linear, branched or cyclic, and the substituent of the substituted alkyl group is a halogen, a hydroxyl group, an aldehyde group And a carboxyl group, an amino group or an amido group, and a hydrogen atom of the unsubstituted alkyl group, the aryl group, the aralkyl group and the alkylaryl group is substituted with a halogen It can have.
l represents an integer of 1 to 3;
Y represents an acid residue of a compound selected from the group consisting of a hydroxyl group or a carboxylic acid having 1 to 20 carbon atoms, a hydrogen acid, an oxo acid, an inorganic thio acid and an organic thio acid having 1 to 20 carbon atoms. )
The volatile organic compound generation inhibitor from polyacetal containing the quaternary ammonium compound solution in any one of [6] [1]-[5].
[7] [1] to [5], including the step of heat-treating the thermally unstable polyacetal having a terminal portion to which the quaternary ammonium compound solution has been added.
Method for producing polyacetal.

  By using the quaternary ammonium compound solution of the present invention, it is possible to provide a polyacetal having good color tone and little generation of formaldehyde, acetaldehyde and acrolein, and further, a polyacetal resin composition having little change in color tone at molding after heat retention. Can be provided.

  Hereinafter, modes for carrying out the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail. In addition, this invention is not limited to the following embodiment, It can variously deform and implement within the range of the summary.

1. Quaternary ammonium compound solution <quaternary ammonium compound (A)>
First, the novel quaternary ammonium compound (A) represented by Formula (1) used in the quaternary ammonium compound solution of the present embodiment will be described.
The quaternary ammonium compound (A) of the present embodiment is represented by the following formula (1).
[(R1) _m (R2) _4-m N ⁺ ] _n X ^n- (1)
In the formula, each R1 independently represents a C1-C30 unsubstituted alkyl group or a substituted alkyl group; a C6-C20 aryl group; a C1-C30 unsubstituted alkyl group or a substituted alkyl group An aralkyl group substituted with at least one aryl group having 6 to 20 carbon atoms; or an aryl group having 6 to 20 carbon atoms is substituted with at least one unsubstituted alkyl group having 1 to 30 carbon atoms or a substituted alkyl group And the unsubstituted alkyl group or substituted alkyl group is linear, branched or cyclic, and the substituent of the substituted alkyl group is a halogen, a hydroxyl group, an aldehyde group, a carboxyl group, an amino group, or A hydrogen atom of an unsubstituted alkyl group, an aryl group, an aralkyl group or an alkylaryl group which is an amido group may be substituted with a halogen.
R2 each independently represents a group represented by the following formula, which has 2 to 60 carbon atoms and 2 to 30 oxygen atoms.
-(RO) k-H
(However, R represents a substituted or unsubstituted alkyl group, and k represents a natural number of 2 or more.)
m and n represent an integer of 1 to 3; The larger the n is, the higher the possibility of side reactions, and in order to obtain high purity, and from the viewpoint of availability and ease, it is particularly preferable that n is 1 and m is 3.
X is an acid residue of a compound selected from the group consisting of a hydroxyl group or a monocarboxylic acid having 1 to 20 carbon atoms, hydrogen acid, oxo acid, an inorganic thio acid and an organic thio acid having 1 to 20 carbon atoms, And a group not containing a nitrogen atom.
When X contains a nitrogen atom, it does not effectively work to suppress the generation of acetaldehyde and acrolein during heating.

  In the formula (1), R 1 is preferably an alkyl group having 1 to 5 carbon atoms or a hydroxyalkyl group having 2 to 4 carbon atoms from the viewpoint of the availability and the ease of production.

Further, in the formula (1), R 2 represents a group represented by the following formula having 2 to 60 carbon atoms and 2 to 30 oxygen atoms.
-(RO) k-H
(However, R represents a substituted or unsubstituted alkyl group, and k represents a natural number of 2 or more.)
By selecting such a group as R 2, it is possible to suppress the generation of formaldehyde, acetaldehyde and acrolein from the polyacetal when heating at high temperature such as heating and melting.
When the carbon number is more than 60 or the oxygen number is more than 30, it may take time to isolate and produce the quaternary ammonium compound.
From the viewpoint of synthesis of quaternary ammonium compounds, the carbon number of R2 is preferably 2 to 10, and the oxygen number is preferably 2 to 5, and from the viewpoint of colorability after melting and heating of polyacetal, the carbon number is 2 to 6 And the oxygen number is more preferably 2-3.

  In the formula (1), X is preferably an acid residue of a monocarboxylic acid from the viewpoint of easy availability. Among them, at least one acid residue selected from the group consisting of formic acid, acetic acid and propionic acid is preferable in terms of ease of handling.

Specific examples of the quaternary ammonium compound (A) of the present embodiment include, for example, 1-hydroxymethoxy-N-((hydroxymethoxy) methyl) -N, N-dimethylmethaneammonium, 2- (2-hydroxyethoxy) ) -N- (2- (2-hydroxyethoxy) ethyl) -N, N-dimethylethane- 1-ammonium, N-ethyl-N, N-bis ((hydromethoxy) methyl) ethaneammonium, 2- (2-hydroxy) Ethoxy) -N- (2- (2-hydroxyethoxy) ethyl) -N, N-dimethylethane-1-ammonium, N, N, N- triethyl 2- (2- (2-hydroxy) ethoxy) ethane 1-ammonium, N- (2- (2- (hydroxymethoxy) ethoxy) ethyl) -N, N-dipropylpropane-1-ammonium , N-(((hydroxymethoxy) methoxy) methyl) -N, N-dipropylpropane-1 -ammonium, N- (2- (2- (2-hydroxyethoxy) ethoxy) ethyl) -N, N-di Hydroxides such as propylpropane-1-ammonium; Hydrochlorides such as hydrochloric acid, bromic acid, hydrofluoric acid, etc .; sulfuric acid, nitric acid phosphoric acid, carbonic acid, oxalic acid, chloric acid, iodic acid, silicic acid, perchloric acid, chlorous acid Acids, hypochlorous acid, chlorosulfuric acid, amidosulfuric acid, disulfuric acid, tripolyphosphoric acid, etc. oxo acid salts such as thiosulfuric acid; formic acid, acetic acid, propionic acid, butanoic acid, isobutyric acid, pentanoic acid, caproic acid And monocarboxylic acid salts such as caprylic acid, capric acid and benzoic acid.
Among them, the hydroxide is preferably used in the form of a salt, in particular a monocarboxylic acid salt, since the hydroxide is strongly alkaline and needs to be handled with care.

<Kinematic viscosity>
The quaternary ammonium compound solution of the present embodiment is a solution of a quaternary ammonium compound (A), and the kinematic viscosity at 15 ° C. is in the range of 0.4 to 10.0 mm ² / s. The kinematic viscosity can be measured using a Ubbelohde viscosity tube.
When the kinematic viscosity is 10.0 mm ² / s or less, a polyacetal having a stable color tone and good thermal stability can be produced.
If the kinematic viscosity is 0.4 mm ² / s or more, sufficient terminal stabilization is possible, which is advantageous for removing an unnecessary solvent. From the viewpoint of not using a large amount of solvent, it is preferably 0.7 mm ² / s or more, more preferably 1.0 mm ² / s or more.
From the viewpoint of obtaining a polyacetal having a stable color tone, it is preferably 7.0 mm ² / s or less, more preferably 5.0 mm ² / s or less, and still more preferably 4.0 mm ² / s or less preferable.

<Solvent>
The solvent of the quaternary ammonium compound (A) may be any liquid which can be dissolved, and it may be liquid at normal temperature or in a desired temperature range to be dissolved. Specific examples thereof include, for example, water, ketones, alcohols, ethers, esters, hydrocarbons, aromatic hydrocarbons, halogenated carbons, nitro compounds, acid anhydrides, acid-halides And amines, amides and nitriles. In addition, after dissolving after mixing a quaternary ammonium compound (A) and a solvent in a glass test tube and mixing well, the test tube is looked at, and if a scene can be recognized, it will be in the dissolved state.
The solvent is preferably a solvent having a small number of atoms, such as water, acetone, and methanol, from the viewpoint of easy availability and easy handling.
When water is used as a solvent, there is no need to provide a step of drying the water during the preparation of the quaternary ammonium compound (A), which can save the heat energy, and further, it is possible to obtain It is possible to prevent deterioration and discoloration of the grade ammonium compound (A). In addition, since formaldehyde is azeotroped with water, removal of formaldehyde generated from polyacetal can be promoted when using a quaternary ammonium compound solution for stabilizing crude polyacetal.

<Quaternary ammonium compound (C)>
The quaternary ammonium compound solution of the present embodiment may contain, in addition to the quaternary ammonium compound (A), a quaternary ammonium compound (C) represented by the following formula (3).
[R3R4R5R6N ⁺ ] _l Y ^l- (3)
In the formula, each of R 3, R 4, R 5 and R 6 independently represents an unsubstituted alkyl group having 1 to 30 carbons or a substituted alkyl group; an aryl group having 6 to 20 carbons; an unsubstituted alkyl having 1 to 30 carbons An aralkyl group in which the group or substituted alkyl group is substituted with at least one aryl group having 6 to 20 carbon atoms; or the aryl group having 6 to 20 carbon atoms has at least one unsubstituted alkyl group having 1 to 30 carbon atoms or Represents an alkylaryl group substituted with a substituted alkyl group, and the unsubstituted alkyl group and the substituted alkyl group are linear, branched or cyclic, and the substituent of the substituted alkyl group is a halogen, a hydroxyl group, an aldehyde group, In a carboxyl group, an amino group, or an amido group, a hydrogen atom of an unsubstituted alkyl group, an aryl group, an aralkyl group and an alkylaryl group is substituted with a halogen It can have.
l represents an integer of 1 to 3;
Y represents an acid residue of a compound selected from the group consisting of a hydroxyl group or a carboxylic acid having 1 to 20 carbon atoms, a hydrogen acid, an oxo acid, an inorganic thio acid and an organic thio acid having 1 to 20 carbon atoms.

As such a quaternary ammonium compound (C), for example, tetramethyl ammonium, tetraethyl ammonium, tetrapropyl ammonium, tetra-n-butyl ammonium, cetyl trimethyl ammonium, tetradecyl trimethyl ammonium, 1,6-hexamethylene bis (Trimethylammonium), decamethylene-bis- (trimethylammonium), trimethyl-3-chloro-2-hydroxypropylammonium, trimethyl (2-hydroxyethyl) ammonium, triethyl (2-hydroxyethyl) ammonium, tripropyl (2-hydroxy) Ethyl) ammonium, tri-n-butyl (2-hydroxyethyl) ammonium, trimethylbenzyl ammonium, triethyl benzyl ammonium, tri Ropylbenzylammonium, tri-n-butylbenzylammonium, trimethylphenylammonium, triethylphenylammonium, trimethyl-2-oxyethylammonium, monomethyltrihydroxyethylammonium, monoethyltrihydroxyethylammonium, octadecyltri (2-hydroxyethyl) Hydroxides such as ammonium and tetrakis (hydroxyethyl) ammonium; Hydrochlorides such as hydrochloric acid, hydrobromic acid and hydrofluoric acid; sulfuric acid, nitric acid phosphoric acid, carbonic acid, oxalic acid, chloric acid, iodic acid, silicic acid, perchloric acid, Oxo acid salts such as chlorous acid, hypochlorous acid, chlorosulfuric acid, amidosulfuric acid, disulfuric acid, tripolyphosphoric acid; thio acid salts such as thiosulfuric acid; formic acid, acetic acid, propionic acid, butanoic acid, isobutyric acid, pentanoic acid, Caproic acid, caprylic acid, capri Acid, benzoic acid, a carboxylic acid salt such as oxalic acid. Among these, hydroxides are strongly alkaline and it is necessary to be careful in handling, and when they are used for the stabilization of polyacetals having unstable ends, coloring occurs in the resulting stabilized polyacetals. As they are also used, they are preferably used in the form of salts, in particular carboxylates.
The quaternary ammonium compounds (C) may be used alone or in combination of two or more.

2. Volatile organic compound generation inhibitor from polyacetal The quaternary ammonium compound solution of the present embodiment can be used as a volatile organic compound generation inhibitor from polyacetal.
The volatile organic compound generation inhibitor from the polyacetal of the present embodiment contains a quaternary ammonium compound (A), a solvent, and, if necessary, the above-mentioned quaternary ammonium compound (C), and further, any of the compounds. It contains a quaternary ammonium compound solution which can contain an additive.

The polyacetal to which the volatile organic compound generation inhibitor (quaternary ammonium compound solution) from the polyacetal of this embodiment acts effectively is a polymer having an oxymethylene group in the main chain, and is a formaldehyde monomer or part thereof. Cyclic oligomers of formaldehyde such as tetramers (trioxane) and tetramers (tetraoxane), and cyclic formals of glycols and diglycols such as ethylene oxide, propylene oxide, epichlorohydrin, 1,3-dioxolane and 1,4-butanediol formal, etc. And polyacetal copolymers obtained by copolymerizing cyclic ethers and cyclic formals. Further, a branched polyacetal copolymer obtained by copolymerizing a monofunctional glycidyl ether, or a polyacetal copolymer having a crosslinked structure obtained by copolymerizing a polyfunctional glycidyl ether can also be used. Furthermore, a polyacetal homopolymer having a block component obtained by polymerizing a formaldehyde monomer or a cyclic oligomer of formaldehyde in the presence of a compound having a functional group such as a hydroxyl group at both ends or one end, such as polyalkylene glycol, Compounds having a functional group such as a hydroxyl group at both ends or one end, for example, a formaldehyde monomer or a cyclic oligomer of formaldehyde such as trimer (trioxane) or tetramer (tetraoxane) in the presence of hydrogenated polybutadiene glycol A polyacetal copolymer having a block component obtained by copolymerizing a cyclic ether or a cyclic formal can also be used.
As described above, the volatile organic compound generation inhibitor (quaternary ammonium compound solution) from the polyacetal of the present embodiment can be used for both polyacetal homopolymer and copolymer.

By the way, polyacetal generally contains a thermally unstable terminal part (a group containing a hydroxymethyl group such as -CH ₂ OH group or-(OCH ₂ ) _n -OH group), so that heating is applied. And formaldehyde, and in some cases acetaldehyde and acrolein are generated, but if the volatile organic compound generation inhibitor from the polyacetal of this embodiment is used, the unstable terminal portion of the polyacetal is decomposed and removed during heating, It is possible to suppress the generation of formaldehyde and the like. In particular, since the polyacetal copolymer has many unstable terminal portions, the volatile organic compound generation inhibitor from the polyacetal of this embodiment can be effectively used for the polyacetal copolymer.

Therefore, the polyacetal copolymer is described in detail below.
The proportion of comonomers such as 1,3-dioxolane in the polyacetal copolymer is generally 0.01 to 60 mol%, preferably 0.03 to 20 mol%, and more preferably 0.05 to 1 mol% relative to 1 mol of trioxane. 15 mol%, most preferably 0.1 to 10 mol% is used.
The polymerization catalyst used when polymerizing the polyacetal copolymer is not particularly limited, but cationic active catalysts such as Lewis acids, proton acids and their esters or anhydrides are preferable.
Examples of Lewis acids include halides of boric acid, tin, titanium, phosphorus, arsenic and antimony, and specifically, boron trifluoride, tin tetrachloride, titanium tetrachloride, phosphorus pentafluoride, pentachloride And phosphorus, antimony pentafluoride and complex compounds or salts thereof. Also, specific examples of protonic acid, ester or anhydride thereof include perchloric acid, trifluoromethanesulfonic acid, perchloric acid tertiary butyl ester, acetyl perchlorate, isopoly acids, heteropoly acids, trimethyloxonium hexafluorophosphate, etc. Can be mentioned. Among them, boron trifluoride; boron trifluoride hydrate; and a coordination complex compound of an organic compound containing an oxygen atom or a sulfur atom and boron trifluoride are preferable, and specifically, boron trifluoride diethyl ether Boron trifluoride di-n-butyl ether can be mentioned as a preferred example.
There is no particular limitation on the polymerization method of the polyacetal copolymer, and in general, it is carried out in bulk polymerization, and either batch system or continuous system is possible.
As the polymerization apparatus, for example, a self-cleaning type extrusion kneader such as a co-kneader, a twin screw continuous extrusion kneader, or a twin paddle continuous mixer can be used, and a monomer in a molten state is supplied to the polymerization machine. As the polymerization proceeds, solid bulk polyacetal copolymer is obtained.

  When the polyacetal having unstable terminal groups as described above is stabilized using the volatile organic compound generation inhibitor from the polyacetal of the present embodiment, the generation of formaldehyde and the like due to the heat treatment can be reduced.

In the volatile organic compound generation inhibitor from the polyacetal of the present embodiment, the concentration of the quaternary ammonium compound (A) in the polyacetal resin composition to be obtained is represented by the following formula (I): It is preferable to use an amount of 0.1 ppb or more and 30 ppm or less on a mass basis in terms of the concentration n of nitrogen derived from the ammonium compound (A).
Within this range, the formation of acrolein and acetaldehyde can be efficiently suppressed. If it is 0.1 ppb or more, acrolein can be effectively suppressed, and if 30 ppm or less, generation of acetaldehyde and yellowing of polyacetal resin can be effectively suppressed. A more preferable range is 0.1 ppm or more and 25 ppm or less, more preferably 1 ppm to 20 ppm, and particularly preferably 5 ppm to 15 ppm.

The nitrogen conversion content n of the above-mentioned quaternary ammonium compound (A) is represented by the following formula (I).
n = S × 14 / T (I)
In the formula, S represents the amount (mass ppm or ppb) of quaternary ammonium compound (A) to the total amount of polyacetal and quaternary ammonium compound (A), 14 is the atomic weight of nitrogen, and T is Represents the molecular weight of the quaternary ammonium compound.
Here, the content of the quaternary ammonium compound (A) is defined in terms of nitrogen based on the number of moles of the quaternary compound contained in the resin composition depending on the molecular weight of the quaternary ammonium compound (A). To avoid major changes.

The amount of nitrogen derived from the quaternary ammonium compound (A) in the polyacetal resin composition can be quantified, for example, by NMR analysis as follows.
After 15 kg of the polyacetal resin composition pellet is freeze-crushed with a phosphorus rex mill etc., it is put into a 100 L SUS autoclave equipped with a stirrer, and 50 L of distilled water is put into it. Then, it is placed in an oven set at 120 ° C., left for 24 hours, and then brought to room temperature, and the solid solution is separated by suction filtration. The resulting liquid is concentrated by an evaporator, and a liquid obtained by mixing about 2.5 ml of a liquid concentrated to about 5 ml with heavy water at 1: 1 (volume ratio) is subjected to NMR analysis, and it is about 3.5 ppm and 3.9 ppm The amount of nitrogen derived from the quaternary ammonium compound (A) is quantified from the peak area in the vicinity.
In addition, when it is clear that the nitrogen source is only the quaternary ammonium compound (A), the nitrogen atomic weight is quantified by a nitrogen analyzer (for example, a nitrogen analyzer TN-2100H manufactured by Mitsubishi Analytech Co., Ltd.) It can also be quantified.

Moreover, when the volatile organic compound generation inhibitor from the polyacetal of this embodiment contains the quaternary ammonium compound (C) represented by Formula (3), the quaternary ammonium in the polyacetal resin composition obtained The concentration of the compound (C) is preferably 0.5 mass ppb to 500 mass ppm in terms of the concentration n ′ ′ ′ of nitrogen derived from the quaternary ammonium compound (C) represented by the following formula (II): It is preferable that
n '''=S''' × 14 / T '''(II)
(Wherein, S ′ ′ ′ represents the amount (mass ppb or ppm) of the quaternary ammonium compound (C) relative to the total amount of the polyacetal and the quaternary ammonium compound (C), and 14 is the atomic weight of nitrogen, T ′ ′ ′ represents the molecular weight of the quaternary ammonium compound (C).)
When the concentration n ′ ′ ′ of the quaternary ammonium compound (C) is 0.5 mass ppb or more, the effect of improving the decomposition rate of the unstable terminal portion of the polyacetal by the combined use of the quaternary ammonium compound (C) Becomes larger. Moreover, the color tone of polyacetal is not impaired even after stabilization if it is 500 mass ppm or less.
Here, the reason for defining the concentration of the quaternary ammonium compound (C) in a nitrogen equivalent amount is that the number of moles of the quaternary ammonium compound (C) relative to the polyacetal varies depending on the molecular weight of the quaternary ammonium compound (C). It is to avoid the problem.

  As described above, even if the polyacetal having unstable terminal groups is stabilized using the volatile organic compound generation inhibitor from the polyacetal of the present embodiment, generation of formaldehyde and the like due to heat treatment can be reduced.

The polyacetal stabilized using the volatile organic compound generation inhibitor from the polyacetal of the present embodiment is, if necessary, a heat stabilizer, an antioxidant, a formaldehyde scavenger, a formic acid scavenger, a UV absorber, and light stability. It can be used in combination with an agent, a mold release agent, a reinforcing material, an electric material, a thermoplastic resin, a thermoplastic elastomer, a pigment and the like.
The heat stabilizer may be an antioxidant, a scavenger of formaldehyde or formic acid, or a combination thereof, and a combination of an antioxidant and a scavenger is preferred.

As the antioxidant, hindered phenol-based antioxidants are preferable. For example, n-octadecyl-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) -propionate, n-octadecyl- 3- (3'-Methyl-5-t-butyl-4'-hydroxyphenyl) -propionate, n-tetradecyl-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) -propionate 1,6-Hexanediol-bis- (3- (3,5-di-t-butyl-4-hydroxyphenyl) -propionate), 1,4-butanediol-bis- (3- (3,5- (3- (3,5-) Di-tert-butyl-4-hydroxyphenyl) -propionate), triethylene glycol-bis- (3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) Propionate), tetrakis- (methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate methane, 3,9-bis (2- (3- (3-t-t-) Butyl-4-hydroxy-5-methylphenyl) propionyloxy) -1,1-dimethylethyl) 2,4,8,10-tetraoxaspiro (5,5) undecane, N, N'-bis-3- ( 3 ', 5'-di-t-butyl-4-hydroxyphenol) pripionylhexamethylenediamine, N, N'-tetramethylenebis-3- (3'-methyl-5'-t-butyl-4-) Hydroxyphenol) propionyldiamine, N, N'-bis- (3- (3,5-di-t-butyl-4-hydroxyphenol) propionyl) hydrazine, N-salicyloyl-N'-salicity Denhydrazine, 3- (N-salicyloyl) amino-1,2,4-triazole, N, N'-bis (2- (3- (3,5-di-butyl-4-hydroxyphenyl) propionyloxy) ethyl And the like.
Among these hindered phenolic antioxidants, triethylene glycol-bis- (3- (3-t-butyl-5-methyl-4-hydroxyphenyl) -propionate), tetrakis- (methylene-3- (3 ') 5,5'-di-t-butyl-4'-hydroxyphenyl) propionate methane is preferred.

  Specific examples of scavengers for formaldehyde and formic acid include (i) compounds and polymers containing formaldehyde-reactive nitrogen, (ii) hydroxides of alkali metals or alkaline earth metals, inorganic acid salts, carboxylates, and the like. An alkoxide etc. are mentioned.

Examples of compounds containing (i) formaldehyde-reactive nitrogen include (1) dicyandiamide, (2) amino-substituted triazines, and (3) co-condensates of amino-substituted triazines with formaldehyde.
(2) As amino-substituted triazine, specifically, guanamine (2,4-diamino-sym-triazine), melamine (2,4,6-triamino-sym-triazine), N-butylmelamine, N-phenylmelamine N, N-diphenylmelamine, N, N-diallylmelamine, N, N ′, N ′ ′-triphenylmelamine, N-methylolmelamine, N, N′-dimethylolmelamine, N, N ′, N ′ ′-trilylmelamine Methylolmelamine, benzoguanamine (2,4-diamino-6-phenyl-sym-triazine), 2,4-diamino-6-methyl-sym-triazine, 2,4-diamino-6-butyl-sym-triazine, 2, 4-diamino-6-benzyloxy-sym-triazine, 2,4-diamino-6-butoxy-sym-triazine, , 4-Diamino-6-cyclohexyl-sym-triazine, 2,4-diamino-6-chloro-sym-triazine, 2,4-diamino-6-mercapto-sym-triazine, 2,4-dioxy-6-amino -Sym-triazine (amelite), 2-oxy-4,6-diamino-sym-triazine (ameline), N, N ', N'-tetracyanoethyl benzoguanamine and the like. (3) Specific examples of the co-condensate of amino-substituted triazine and formaldehyde include melamine-formaldehyde polycondensate and the like. Among these, dicyandiamide, melamine and melamine-formaldehyde polycondensates are preferred.

(I) As the polymer having a formaldehyde reactive nitrogen group, for example, (1) polyamide resin, (2) acrylamide and its derivative or acrylamide and its derivative and other vinyl monomer are polymerized in the presence of metal alcoholate (3) polymers obtained by polymerizing acrylamide and its derivatives or acrylamide and its derivatives with other vinyl monomers in the presence of radical polymerization, (4) amines, amides, ureas, urethanes, etc. The polymer etc. which contain a nitrogen group are mentioned.
Specific examples of the polyamide resin of (1) include nylon 4-6, nylon 6, nylon 6-6, nylon 6-10, nylon 6-12, nylon 12 and the like, and copolymers thereof, nylon 6/6. -6, nylon 6 / 6-6 / 6-10, nylon 6 / 6-12 and the like. (2) As a polymer obtained by polymerizing acrylamide and its derivative or acrylamide and its derivative and other vinyl monomers in the presence of metal alcoholate, specifically, poly-β-alanine copolymer etc. are mentioned. Be These polymers can be produced by the methods described in JP-B-6-12259, JP-B-5-87096, JP-B-5-47568 and JP-A-3-234729. (3) A polymer obtained by polymerizing acrylamide and a derivative thereof or acrylamide and a derivative thereof and another vinyl monomer in the presence of radical polymerization can be produced by the method described in JP-A-3-28260. .

  (Ii) As hydroxides, inorganic acid salts, carboxylates and alkoxides of alkali metals or alkaline earth metals, specifically, hydroxides such as sodium, potassium, magnesium, calcium or barium, carbonates of the metals Salts, phosphates, silicates, borates, carboxylates may be mentioned. The carboxylic acid of the carboxylic acid salt is a saturated or unsaturated aliphatic carboxylic acid having 10 to 36 carbon atoms and the like, and these carboxylic acids may be substituted by a hydroxyl group. Examples of saturated aliphatic carboxylic acids include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, myristic acid and celloplastic acid. Examples of unsaturated aliphatic carboxylic acids include undecylenic acid, oleic acid, elaidic acid, cetoleic acid, erucic acid, brassic acid, sorbic acid, linolic acid, linolenic acid, arachidonic acid, propiolic acid, stearic acid and the like. Moreover, methoxide of the said metal, ethoxide etc. are mentioned as an alkoxide.

Examples of the weathering (light) stabilizer include (i) benzotriazole based substances, (ro) oxalic acid anilide based substances and (ha) hindered amine based substances.
(I) As a benzotriazole-based substance, specifically, 2- (2'-hydroxy-5'-methyl-phenyl) benzotriazole, 2- [2'-hydroxy-3,5-di-t-butyl -Phenyl) benzotriazole, 2- [2'-hydroxy-3,5-di-isoamyl-phenyl) benzotriazole, 2- [2'-hydroxy-3,5-bis- (α, α-dimethylbenzyl) phenyl ] 2 H-benzotriazole, 2- (2'-hydroxy-4'-octoxyphenyl) benzotriazole, etc., and preferably 2- [2'-hydroxy-3,5-bis- (α, α-) Dimethylbenzyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-3,5-di-t-butyl-phenyl) benzotriazole can be mentioned.
(Ii) As the oxalic acid anilide type substance, specifically, 2-ethoxy-2'-ethyl oxalic acid bis anilide, 2-ethoxy-5-t-butyl-2'-ethyl oxalic acid bis anilide And 2-ethoxy-3'-dodecyl oxalic acid bisanilide. These substances may be used alone or in combination of two or more.
(Iii) As the hindered amine substance, specifically, 4-acetoxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 4-acryloyloxy -2,2,6,6-Tetramethylpiperidine, 4- (phenylacetoxy) -2,2,6,6-tetramethylpiperidine 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4- Methoxy-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethylpiperidine, 4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine, 4- Benzyloxy-2,2,6,6-tetramethylpiperidine, 4-phenoxy-2,2,6,6-tetramethylpiperidine, 4- (E (Carbamoyloxy) -2,2,6,6-tetramethylpiperidine, 4- (cyclohexylcarbamoyloxy) -2,2,6,6-tetramethylpiperidine, 4- (phenylcarbamoyloxy) -2,2,6, 6-Tetramethylpiperidine, bis (2,2,6,6-tetramethyl-4-piperidine) -carbonate, bis (2,2,6,6-tetramethyl-4-piperidyl) -oxalate, bis (2, 2,6,6-Tetramethyl-4-piperidyl) -malonate, bis (2,2,6,6-tetramethyl-4-piperidyl) -sebacate, bis (2,2,6,6-tetramethyl-4) -Piperidyl) -adipate, bis (2,2,6,6-tetramethyl-4-piperidyl) -terephthalate, 1,2-bis (2,2,6,6-tetrame) Ru-4-piperidyloxy) -ethane, α, α'-bis (2,2,6,6-tetramethyl-4-piperidyloxy) -p-xylene, bis (2,2,6,6-tetramethyl) -4-piperidyl) tolylene-2,4-dicarbamate, bis (2,2,6,6-tetramethyl-4-piperidyl) -hexamethylene-1,6-dicarbamate, tris (2,2,6,6 6-Tetramethyl-4-piperidyl) -benzene-1,3,5-tricarboxylate, tris (2,2,6,6-tetramethyl-4-piperidyl) -benzene-1,3,4-tricarboxy And the like, preferably bis (2,2,6,6-tetramethyl-4-piperidyl) -sebacate. The above-mentioned hindered amine-based substances may be used alone or in combination of two or more.
Further, a combination of the above-mentioned benzotriazole-based substance, oxalic acid anilide-based substance and hindered amine-based substance is more preferable.

The release agent may, for example, be an alcohol, an ester of an alcohol and a fatty acid, an ester of an alcohol and a dicarboxylic acid, or a silicone oil.
Specific examples of the alcohol include monohydric alcohols and polyhydric alcohols. Examples of monohydric alcohols include octyl alcohol, capryl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, lauryl alcohol, tridecyl alcohol, and the like. Myristyl alcohol, bentadecyl alcohol, cetyl alcohol, hebutadecyl alcohol, stearyl alcohol, oleyl alcohol, nonadecyl alcohol, eicosyl alcohol, pehenyl alcohol, ceryl alcohol, melicyl alcohol, 2-hexyldecanol, 2-octyldodecanol, 2-decyl tetradecanol, unilin alcohol and the like can be mentioned. The polyhydric alcohol is a polyhydric alcohol containing 2 to 6 carbon atoms, and examples thereof include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol dipropylene glycol, butanediol, pentanediol, hexanediol, glycerin, Examples include diglycerin, triglycerin, threitol, erythritol, pentaerythritol, arabitol, ribitol, xylitol, sorbite, sorbitan, sorbitol, mannitol and the like.
The ester of alcohol and fatty acid is preferably derived from fatty acid compounds among fatty acid compounds, preferably fatty acid selected from palmitic acid, stearic acid, behenic acid, montanic acid and polyhydric alcohol selected from glycerin, pentaerythritol, sorbitan, sorbitol Fatty acid esters. The hydroxyl group of these fatty acid ester compounds may or may not be present, and does not limit the fatty acid ester compound. For example, it may be a monoester, a diester or a triester. Further, the hydroxyl group may be blocked with boric acid or the like.
Specifically, preferred fatty acid esters are glycerin monopalmitate, glycerin dipalmitate, glycerin tripalmitate, glycerin monostearate, glycerin distearate, glycerin tristearate, glycerin monobehenate, glycerin dibehenate, Glycerin tribehenate, Glycerin monomontanate, Glycerin dimontanate, Glycerin trimontanate, Pentaerythritol monopalmitate, Pentaerythritol dipalmitate, Pentaerythritol tripalmitate, Pentaerythritol tetrapalmitate, Pentaerythritol monostearate , Pentaerythritol distearate, pentaerythritol tristearate, pentaerythritol tetrastearate Pentaerythritol monobehenate, pentaerythritol dibehenate, pentaerythritol tribehenate, pentaerythritol tetrabehenate, pentaerythritol monomontanate, pentaerythritol dimontanate, pentaerythritol trimontanate, pentaerythritol tetramontanate, Sorbitan monopalmitate, sorbitan dipalmitate, sorbitan tripalmitate, sorbitan monostearate, sorbitan distearate, sorbitan tristearate, sorbitan monobehenate, sorbitan dibehenate, sorbitan tribehenate, sorbitan monomontanate Sorbitan dimontanate, sorbitan trimontanate, sorbitol monopalmitate, sorbitol dipa Mitate, Sorbitol tripalmitate, Sorbitol monostearate, Sorbitol distearate, Sorbitol tristearate, Sorbitol monobehenate, Sorbitol dibehenate, Sorbitol tribehenate Sorbitol monomontanate, Sorbitol dimontanate, Sorbitol trimonta And the like.
In addition, boric acid esters of glycerin monofatty acid ester are also mentioned as aliphatic ester compounds in which the hydroxyl group is blocked with boric acid or the like. The ester of alcohol and dicarboxylic acid is methyl alcohol as the alcohol, ethyl alcohol, propyl alcohol, n-butyl alcohol, isobutyl alcohol, t-butyl alcohol, n-amyl alcohol, 2-pentanol, n-heptyl alcohol, n-octyl Saturated or unsaturated alcohols such as alcohol, n-nonyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol and the like, dicarboxylic acid as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, Examples thereof include monoesters and diesters with suberic acid, azelaic acid, sebacic acid, undecanic acid, brassic acid, maleic acid, fumaric acid, glutaconic acid and the like.

3. Method for Producing Polyacetal In this embodiment, a polyacetal having a thermally unstable terminal end can be pre-stabilized using the quaternary ammonium compound solution of this embodiment to produce a stabilized polyacetal. .
Specifically, the solution of the quaternary ammonium compound of the present embodiment can be added to a polyacetal having thermally unstable terminal portions, and the solution can be stabilized by heat treatment.
A process comprising adding a quaternary ammonium compound solution to a thermally unstable terminal end polyacetal (hereinafter sometimes referred to as “crude polyacetal”) of the present embodiment and heat treating it, The method for producing the polyacetal of the embodiment will be described by way of specific examples.

In the present embodiment, the step of (co) polymerization of crude polyacetal can be included. Under the present circumstances, there is no limitation in the (co) polymerization method, It can obtain by performing superposition | polymerization in accordance with a conventional method. Hereinafter, materials that can be preferably used in producing a crude polyacetal (polyacetal (co) polymerization step) will be described.
<Trioxane>
Trioxane is a cyclic trimer of formaldehyde and is generally obtained by reacting an aqueous formalin solution in the presence of an acidic catalyst.
Since this trioxane may contain impurities having a chain transfer action such as water, methanol, formic acid, methyl formate and the like, these impurities may be added by a method such as distillation as a step prior to the step of conducting the polymerization reaction It is preferable to remove and purify.
In that case, the total amount of the impurities having a chain transfer action is preferably 1 × 10 ⁻³ mol or less, more preferably 0.5 × 10 ⁻³ mol or less, with respect to 1 mol of trioxane.
By reducing the amount of the impurities as in the above numerical value, the polymerization reaction rate can be sufficiently increased for practical use, and a polyacetal having excellent thermal stability can be obtained.

<Cyclic ether and / or cyclic formal>
When the polyacetal is a copolymer, cyclic ethers and / or cyclic formals can be used as comonomers. These are components copolymerizable with formaldehyde and the trioxane.
The cyclic ether or cyclic formal is not limited to, for example, ethylene oxide, propylene oxide, butylene oxide, epicurolol hydrin, epibromohydrin, styrene oxide, oxatane, 1,3-dioxolane And ethylene glycol formal, propylene glycol formal, diethylene glycol formal, triethylene glycol formal, 1,4-butanediol formal, 1,5-pentanediol formal, 1,6-hexanediol formal and the like. From the viewpoint of availability, 1,3-dioxolane and 1,4-butanediol formal are preferable. One of these may be used alone, or two or more may be used in combination.
The amount of cyclic ether and / or cyclic formal added is preferably in the range of 1 × 10 ^{−2 to} 20 × 10 ⁻² mol with respect to 1 mol of the trioxane from the viewpoint of the mechanical strength of the polyacetal copolymer to be obtained. It is preferably 1 × 10 ^-2 to 15 × 10 ^-2 mol, more preferably 1 × 10 ^-2 to 10 × 10 ^-2 mol, and still more preferably 1 × 10 ^{-2 to} 5 × 10 ^-2 It is mol.

<Polymerization catalyst>
Examples of the polymerization catalyst used in the (co) polymerization step of the polyacetal include boric acid represented by Lewis acid, tin, titanium, phosphorus, arsenic and an antimonide. In particular, from the viewpoint of availability, boron trifluoride, boron trifluoride hydrate, and a coordination complex compound of an organic compound containing oxygen atom or sulfur atom and boron trifluoride are preferable. In particular, boron trifluoride, boron trifluoride diethyl etherate, and boron trifluoride di-n-butyl etherate are mentioned as preferable examples. One of these may be used alone, or two or more may be used in combination.
The addition amount of the polymerization catalyst is preferably in the range of 0.1 × 10 ^{−5 to} 0.1 × 10 ⁻³ mol, and more preferably 0.3 × 10 ^{−5 to} 0.5 × 10, per 1 mol of the trioxane. ^-4 in the range of mol, more preferably 0.5 × 10 ^-5 ~0.4 × 10 ^- in the range of 4 mol.
By setting the addition amount of the polymerization catalyst within the above range, it is possible to stably carry out the polymerization reaction for a long time stably while reducing the amount of scale generation in the feed portion of the polymerization reactor.

<Low molecular weight acetal>
In the (co) polymerization process of polyacetal, low molecular weight acetals represented by the following general formula can also be used.
R- (CH ₂ -O) n -R
(Wherein R represents any one selected from the group consisting of hydrogen, a branched or linear alkyl group, a branched or linear alkoxy group, and a hydroxyl group. N is 1 or more and 20) Represents the following integer :)
The low molecular weight acetal functions as a chain transfer agent in the polymerization step, and is an acetal having a molecular weight of 200 or less, preferably 60 to 170. By using an acetal having the above molecular weight, the molecular weight of the target polyacetal can be adjusted finally.
Examples of the low molecular weight acetal represented by the above general formula include, but are not limited to, methylal, methoxymethylal, dimethoxymethylal, trimethoxymethylal and the like. One of these may be used alone, or two or more may be used in combination.
The addition amount of the low molecular weight acetal represented by the general formula is 0.1 × 10 ^{−4 to} 0.6 × 10 ^{−2 with} respect to 1 mol of the trioxane from the viewpoint of controlling the molecular weight of the target polyacetal in a suitable range A range of mol is preferable, a range of 0.1 × 10 ^{−4 to} 0.6 × 10 ⁻³ mol is more preferable, and a range of 0.1 × 10 ^{−4 to} 0.1 × 10 ⁻³ mol is more preferable.

In this embodiment, the crude polyacetal is stabilized by adding a quaternary ammonium compound solution and heat treating.
Here, although there is no limitation on the aspect of the heat treatment of the crude polyacetal to which the quaternary ammonium compound solution is added, for example, the following two can be mentioned.
One of them is to add the quaternary ammonium compound solution when heating and melting the crude polyacetal, and the other one is to add the quaternary ammonium compound solution to the crude polyacetal in a slurry state It is to heat.

First, heat treatment in the case where the crude polyacetal is melted is described.
The crude polyacetal can be melted, for example, by a vented single screw extruder, a vented twin screw extruder, or the like. The heat treatment is preferably performed at a temperature which is equal to or higher than the melting point of polyacetal and equal to or lower than 260 ° C. If the temperature exceeds 260 ° C., problems of coloring and decomposition of the polymer main chain (lower molecular weight) may occur. In this case, the quaternary ammonium compound solution may be previously added to the crude polyacetal before melting the crude polyacetal, or after melting the crude polyacetal, the quaternary ammonium compound solution may be melted. You may add to polyacetal.

  As a method of adding the quaternary ammonium compound solution to the crude polyacetal before melting in advance, for example, converting the quaternary ammonium compound solution into the amount of the quaternary ammonium compound (A) with respect to the crude polyacetal Mixing after 0.1-5 mass% addition can be mentioned. In this case, the mixing may be performed using a general solid mixer such as a horizontal cylindrical type, a V-type, a ribbon type, a paddle type, or a high speed flow type. Also, the quaternary ammonium compound solution may be directly added to the chute portion feeding the polyacetal to the extruder, or directly to the extruder main body from the feed port of the extruder until the polyacetal is melted. Good.

  In addition, as another method of previously adding the quaternary ammonium compound solution to the crude polyacetal before melting, for example, the crude polyacetal is introduced into the quaternary ammonium compound solution to once make a slurry, and this slurry is appropriately filtered And a method of drying. In this case, the amount of use of the quaternary ammonium compound (A) is controlled by controlling the concentration of the quaternary ammonium compound (A) in the quaternary ammonium compound solution and the liquid content of the polyacetal after filtration. be able to.

  The crude polyacetal to which the quaternary ammonium compound solution is added by the above method is dried as it is or as required, and then melted by an extruder or the like to be subjected to a heat treatment. During melting, it may be stabilized by adding at least one member of water, methanol and the like which are conventionally known decomposition accelerators such as water and methanol, or subjecting to heat treatment without adding anything else. May be It is preferable to add 0.1-5 mass parts with respect to 100 mass parts of polyacetals as addition amount of the decomposition accelerators conventionally used, such as amines, water, methanol, etc. In addition, other quaternary ammonium compounds (quaternary ammonium compounds (C) and the like) may be further added as necessary. These decomposition accelerators such as amines, water, methanol and quaternary ammonium compounds can be added singly or in combination of two or more.

  On the other hand, when adding the quaternary ammonium compound solution to the crude polyacetal in the molten state after melting the crude polyacetal, the amount of water and organic solvents such as methanol contained in the solution is 100 parts by mass of the crude polyacetal Preferably, it is about 0.1 to 5 parts by mass. At this time, in addition to the quaternary ammonium compound solution, conventionally known amines and other quaternary ammonium compounds (quaternary ammonium compounds (C) and the like) may be separately added.

In the present embodiment, the amount of use of the quaternary ammonium compound (A) in the heat treatment step is not limited, but the concentration of the quaternary ammonium compound (A) is represented by the following quaternary formula (I '). It is preferably 0.1 mass ppb to 30 mass ppm, more preferably 0.1 mass ppm to 25 mass ppm, still more preferably 1 mass ppm in terms of nitrogen concentration n ′ derived from the ammonium compound (A) The amount is 20 to 20 ppm by mass, particularly preferably 5 to 10 ppm.
n '= S' × 14 / T '(I')
In the formula, S ′ represents the amount (mass ppb or ppm) based on the total mass of the crude polyacetal of the quaternary ammonium compound (A) and the quaternary ammonium compound (A), 14 is the atomic weight of nitrogen, T ′ Represents the molecular weight of the quaternary ammonium compound (A). )
If the nitrogen concentration n 'derived from the quaternary ammonium compound (A) is 0.1 mass ppb or more, unstable terminal portions can be decomposed in a short time, and if it is 30 mass ppm or less, stabilization is achieved. Even after that, the color tone of the polyacetal is not impaired.
Here, the reason for expressing the concentration of the quaternary ammonium compound (A) in terms of nitrogen concentration is to avoid the dependence on the molecular weight of the quaternary ammonium compound (A) as described above. .

In the method for producing polyacetal according to this embodiment, the heat treatment step of the crude polyacetal to which the quaternary ammonium compound solution is added is carried out after the polymerization catalyst remaining in the crude polyacetal obtained by the polymerization reaction is deactivated. It may be carried out or may be carried out without deactivating the polymerization catalyst.
Furthermore, the method for producing the polyacetal of the present embodiment may include a known stabilization treatment, in which case the heat treatment step of the crude polyacetal to which the quaternary ammonium compound solution is added is performed after the known stabilization treatment. The present invention may be applied to polyacetals in which a part of the still unstable end remains.

Deactivation of the polymerization catalyst can be carried out by using crude polyacetal obtained by polymerization reaction, ammonia, amines such as triethylamine, tri-n-butylamine, etc., hydroxides of alkali metals or alkaline earth metals, inorganic acid salts, organic acids It can be introduced into an aqueous solution or an organic solvent solution containing at least one of catalyst neutralization deactivators such as salts, and generally stirred for several minutes to several hours in a slurry state. In this case, the slurry after neutralization and deactivation of the catalyst is filtered and washed to remove unreacted monomers, catalyst neutralization / deactivation agents and catalyst neutralization salts, and then dried.
In addition, a method of deactivating the polymerization catalyst by contacting a vapor of ammonia, triethylamine or the like with the crude polyacetal, or contacting at least one of hindered amines, triphenylphosphine, calcium hydroxide and the like with the crude polyacetal in a mixer A method of deactivating the catalyst can also be used. In addition, the above-mentioned stabilization method is performed using a polyacetal in which the polymerization catalyst is reduced in volatilization by heating in a inert gas atmosphere at a temperature not higher than the melting point of the crude polyacetal without deactivating the polymerization catalyst May be
The above deactivating operation of the polymerization catalyst and the volatilization reducing operation of the polymerization catalyst may be performed after grinding the crude polyacetal obtained by the polymerization reaction, if necessary.

  The above-mentioned heat treatment step (stabilization of polyacetal) can be carried out by appropriately using a conventionally known apparatus and operation method. Furthermore, conventionally known amines such as ammonia and triethylamine may be used in combination.

When the quaternary ammonium compound (C) represented by Formula (3) is used in combination in the above-mentioned heat treatment step (stabilization of polyacetal), the amount of use of the quaternary ammonium compound (C) is the following formula (II ′) It is preferable that it is 0.5 mass ppb-500 mass ppm preferably in conversion of concentration n '''' of the nitrogen derived from the quaternary ammonium compound (C) represented by these.
n '''' = S '''' × 14 / T '' (II ')
(Wherein, S ′ ′ ′ ′ represents the amount (mass ppb or ppm) based on the total mass of the crude polyacetal of quaternary ammonium compound (C) and quaternary ammonium compound (C), and 14 is an atomic weight of nitrogen And T ′ ′ ′ ′ represents the molecular weight of the quaternary ammonium compound (C).
When the amount of use of the quaternary ammonium compound (C) n ′ ′ ′ ′ is 0.5 mass ppb or more, the decomposition rate of the unstable terminal portion of the polyacetal is improved by the combined use of the quaternary ammonium compound (C) The effect Moreover, the color tone of polyacetal is not impaired even after stabilization if it is 500 mass ppm or less.
Here, the amount of the quaternary ammonium compound (C) to be used is defined in terms of nitrogen, because the number of moles of the quaternary ammonium compound (C) relative to the polyacetal varies depending on the molecular weight of the quaternary ammonium compound (C). In order to avoid

The stable polyacetal obtained as described above generally comprises, if necessary, an antioxidant, a formaldehyde scavenger, a formic acid scavenger, a UV absorber, a heat stabilizer, a light stabilizer, a mold release agent, a reinforcing material, It is provided for practical use after being mixed with one or more compounding agents such as electric materials, thermoplastic resins, thermoplastic elastomers, pigments and the like in an extruder or the like.
There are no particular restrictions on the timing of compounding, and depending on the type of compounding agent, for example, it may be added in advance to the crude polyacetal before the unstable terminal is decomposed and removed, and the unstable terminal may It may be added to the depolymerized polyacetal.

Next, the terminal group contained in the polyacetal which can be stabilized by the quaternary ammonium compound solution of the present embodiment will be described.
As a terminal group which a plurality of polyacetal (co) polymer chains constituting the polyacetal have as a whole, in addition to a group containing a hydroxymethyl group such as the above-mentioned -CH ₂ OH group or-(OCH ₂ ) _n -OH group alkoxyl groups such as methoxyl group (-OCH _3), hydroxyalkyl groups such as hydroxyethyl group (-CH ₂ CH ₂ OH), and formate groups.

The terminal alkoxyl groups are generally formed by formal, which is a molecular weight regulator added at the polymerization stage. For example, when methylal ((CH ₃ O) ₂ CH ₂ ) is used as a molecular weight modifier, a methoxyl group is formed as a terminal group. The carbon number of the terminal alkoxyl group is generally 1 to 10 carbon atoms, particularly 1 to 3 carbon atoms, from the viewpoint of synthesis and purification of formal as a molecular weight modifier.

The terminal hydroxyalkyl group such as hydroxyethyl group or hydroxybutyl group is derived from the above-mentioned cyclic ether or cyclic formal used as a raw material comonomer of polyacetal, and is formed in the following process.
That is, when polymerizing a polyacetal in which an oxyalkylene group derived from a cyclic ether or a cyclic formal is inserted in the repetition of a polyacetal unit, a thermally unstable terminal hydroxy is first caused by a small amount of water etc. methyl group (-CH ₂ OH) is generated. The terminal unstable moiety is decomposed by the stabilization treatment, and the decomposition proceeds in the main chain including the polyacetal unit and the oxyalkylene unit to reach the site of the oxyalkylene unit, and the oxy of the site is reached. The alkylene units are converted to stable terminal hydroxyalkyl groups such as hydroxyethyl and hydroxybutyl groups. The carbon number of the hydroxyalkyl group is at least 2 and generally 2 to 10 in terms of synthesis and purification of the cyclic ether and the cyclic formal.

On the other hand, when a hydroxymethyl group is present as a terminal group in the polyacetal, particularly when heated by molding or the like, the hydroxymethyl group is released from the terminal to form formaldehyde. Therefore, when many terminal hydroxymethyl groups are present, the amount of formaldehyde generated is excessive.
It is the quaternary ammonium compound (A) having R2 used in this embodiment that plays a role to suppress this formation, and this terminal hydroxymethyl group is decomposed and removed by the action of the quaternary ammonium compound (A). This is thought to suppress the formation of formaldehyde.
Furthermore, the quaternary ammonium compound (A) used in the present embodiment is a trace amount of formaldehyde generated from a trace of unstable terminals remaining without being removed in the polyacetal, in addition to the decomposition and removal of the above-mentioned terminal hydroxymethyl group. Acetaldehyde and acrolein are also polymerized by anionic polymerization at the time of cooling after heating and melting such as molding, and are also involved in immobilizing the polyacetal resin composition, thereby reducing the generation of formaldehyde, acetaldehyde and acrolein, etc. Conceivable. However, the mechanism of the effect of the present embodiment is not limited to these.
In the present embodiment, the carbon number of R2 of the quaternary ammonium compound (A) is 2 to 10, and the number of oxygen is 2 to 5. With such carbon number and oxygen number, the quaternary ammonium compound (A) can be efficiently left in the polyacetal even after heating, whereby volatilization at the time of cooling after the above-mentioned heating and melting It is possible to reduce the generation of toxic organic substances.
The carbon number and the oxygen number of R2 should be large from the viewpoint of suppressing the generation of volatile organic substances, but on the other hand, too large may cause coloring of a molded body containing the same. Therefore, it is preferable to set the value to an appropriate value in view of the balance between the suppression of the generation of volatile organic substances and the prevention of coloring in consideration of the heat treatment temperature, time, and the like. Specifically, the number of carbon atoms is preferably 2 to 6, and the number of oxygen is preferably 2 to 3, and particularly preferably 4 or 2 carbon atoms.

  EXAMPLES Hereinafter, the present invention will be described by way of specific examples and comparative examples with the examples, but the present invention is not limited to the following examples.

The evaluation method of the various characteristics employ | adopted in the Example and the comparative example is demonstrated.
<Method of measuring kinematic viscosity>
An empty Ubbelohde viscosity tube was placed in a thermostat set at 15 ° C., and left for 30 minutes.
Thereafter, the target sample was put in, the fall time between the two reference lines in the time measuring ball was measured, and the kinematic viscosity was determined.
<Quantification of formaldehyde, acetaldehyde and acrolein>
From a polyacetal copolymer composition pellet using a Toshiba Corporation IS- 100GN injection molding machine, cylinder temperature 200 ° C, injection pressure 60MPa, injection time 15 seconds, cooling time 20 seconds, mold temperature 80 ° C The composition was heated and melted to produce a flat-plate-like molded piece of dimensions 130 mm × 110 mm × 3 mm.
After leaving for 24 hours in a temperature-controlled room kept at 23 ° C. and 50% humidity, it was put in an aluminum bag and packed. One molding piece was put in a 10 L Tedlar (registered trademark) bag having a valve and opened and sealed 14 days after molding, and nitrogen substitution was sufficiently performed. Thereafter, after exhausting all the internal nitrogen, 5.00 L of nitrogen was enclosed in a Tedlar® bag. I prepared two of these.
Thereafter, the Tedlar® bag is placed in an oven having two sampling ports in communication with the outside at the top of the inside, and the Tedlar® bag is connected to the sampling port and left at 80 ° C. for 2 hours did.
Then connect a DNPH (2,4-dinitrophenylhydrazine) cartridge to the outside of the sampling port connected to one Tedlar bag and open the valve on the Tedlar bag to make the polyacetal copolymer composition 4.00 L of gas generated from the product was passed through the DNPH cartridge.
The DNPH cartridge was flushed at a constant speed with 5 mL of acetonitrile, and formaldehyde and acetaldehyde were recovered in a 10 mL volumetric flask.
Thereafter, the solution was made up to 10 mL with water and thoroughly mixed.
This mixture is dispensed into vials, and using DNPH standard solution as the standard solution and water / acetonitrile (52/48) as the separation solution by HPLC manufactured by Shimadzu Corporation, conditions of flow rate 1 mL / min, column temperature 40 ° C. The amount of formaldehyde and acetaldehyde generated per mass of polyacetal copolymer composition was measured in ppm.

Connect the CNET (O- (4-cyano-2-ethoxybenzyl) hydroxylamine) cartridge to the outside of the sampling port connected to one remaining Tedlar bag and open the Tedlar bag valve. Then, 4.00 L of gas generated from the polyacetal copolymer composition was passed through a CNET cartridge.
The CNET cartridge was flushed with 5 mL of acetonitrile at a constant speed, and acrolein was collected in a 10 mL volumetric flask.
Thereafter, the solution was made up to 10 mL with water and thoroughly mixed.
This mixture is dispensed into vials, and a CNET standard solution is used as the standard solution, and a water / acetonitrile (40/60) is used as the separation solution in HPLC manufactured by Shimadzu Corporation, conditions of flow rate 1 mL / min, column temperature 40 ° C. The acrolein generated per mass of polyacetal copolymer composition was measured by ppb.

Powder color tone
Put 100 g of crude polyacetal copolymer (P-1) described later and a predetermined amount of quaternary ammonium compound solution into a polyethylene bag, mix well, spread evenly on a SUS-made pad, and cut at 150 ° C. I let it dry.
The top of the vat after drying was visually checked, and the color tone characteristics of the powder were evaluated.
There is no color unevenness, but if it is yellowish or brownish, △
There was no color unevenness and it was white when it was ○.

<Odor during molding>
From a polyacetal copolymer composition pellet using a Toshiba Corporation IS- 100GN injection molding machine, cylinder temperature 200 ° C, injection pressure 60MPa, injection time 15 seconds, cooling time 20 seconds, mold temperature 80 ° C The composition was heated and melted to produce a flat-plate-like molded piece of dimensions 130 mm × 110 mm × 3 mm.
The odor which came out of the molding piece which came out of the mold was evaluated on the basis of the following references | standards, and when it was (circle), it was generally judged that the odor was low.
If you smell formaldehyde with a strong nose: ×
If you have a sweet odor like caramel: △
When there is almost no odor: ○

<Molded color tone>
A flat plate of dimensions 40 mm × 60 mm × 3 mm with a cylinder temperature of 200 ° C., an injection pressure of 60 MPa, an injection time of 15 seconds, a cooling time of 20 seconds and a mold temperature of 80 ° C. 1002 test pieces were prepared.
The 1001st and 1002st test pieces were overlapped, and yellowness (b value) was measured with a light source of D65 using a Minolta manufactured handy color tester (CR-200).
If the b value is -0.8 or less,
If the b value exceeds −0.8 but is −1.6 or less, it is judged as good.

<Production of Solution Containing Quaternary Ammonium Compound (A) Represented by Formula (1)>
All the waters used in the following Production Examples 1 to 11 are deionized water, and all the kinematic viscosities are values at 15 ° C.
Production Example 1
14.1 g of 2- (2-hydroxyethoxy) ethyl acetate, 5.6 g of trimethylamine, 15.0 g of methanol and 0.1 g of water are introduced into a pressure-resistant container having an inner volume of 60 ml which can be sealed, and stirred with a shaker. While heating to 120.degree. The mixture was allowed to react for 6 hours and cooled to obtain the contents. As a result of analyzing the contents, 2- (2-hydroxyethoxy) ethyl-N, N, N-trimethylethane-1-ammonium acetate was obtained in a yield of 95%.
15 g of water is added to 30 g of this solution, and the mixture is concentrated to 30 g with an evaporator at 80 ° C., and water is added to make 60 g. Concentrate again to 30 g and then add water to 60 g. This operation was repeated 10 times, concentrated to 15 g, water was gradually added, and the dynamic viscosity was adjusted to 1.5 mm ² / s. This quaternary ammonium compound solution is referred to as A-1.
The structural formulas (R1, R2 and X) of the quaternary ammonium compound (A) in solution A-1 confirmed by NMR were as shown in Table 1.

Production Example 2
Dynamic viscosity is adjusted to 1.9 mm ² / s using 18.2 g of 2- (2- (2-hydroxyethoxy) ethoxy) ethyl acetate instead of 14.1 g of 2- (2-hydroxyethoxy) ethyl acetate It carried out like manufacture example 1 except having carried out. This solution is referred to as A-2.
Structural formula (R1, R2 and X) of the quaternary ammonium compound (A) in A-2 liquid confirmed by NMR was as showing in Table 1.
Production Example 3
Production Example 1 was repeated except that 7.8 g of triethylamine was used instead of 5.6 g of trimethylamine, 11.4 g of 2- (2-hydroxyethoxy) ethyl acetate was used, and the kinematic viscosity was adjusted to 1.6 mm ² / s. It carried out similarly. This solution is referred to as A-3.
The structural formulas (R1, R2 and X) of the quaternary ammonium compound (A) in solution A-3 confirmed by NMR were as shown in Table 1.
Production Example 4
In place of 5.6 g of trimethylamine, 7.8 g of triethylamine is used, and in place of 2- (2-hydroxyethoxy) ethyl acetate, 14.8 g of 2- (2- (2-hydroxyethoxy) ethoxy) ethyl acetate is used, It carried out like manufacture example 1 except having adjusted kinematic viscosity to 2.1 mm < ² > / s. This solution is referred to as A-4.
Structural formula (R1, R2 and X) of the quaternary ammonium compound (A) in A-4 liquid confirmed by NMR was as showing in Table 1.
Production Example 5
In place of 5.6 g of trimethylamine, 9.4 g of 2- [2- (dimethylamino) ethoxy] ethanol was used, 10.5 g of 2- (2-hydroxyethoxy) ethyl acetate was used, and the dynamic viscosity was 1.7 mm ² / It carried out like manufacture example 1 except having adjusted to s. This solution is referred to as A-5.
The structural formulas (R1, R2 and X) of the quaternary ammonium compound (A) in solution A-5 confirmed by NMR were as shown in Table 1.

Production Example 6
In a 10 ml microwave reaction tube, 5.0 g of trimethylamine and 2.63 g of 2- (2-chloroethoxy) ethanol were placed, and stirred at 150 ° C. for 1 hour while being irradiated with microwaves. After completion of the reaction, the reaction solution was dried under reduced pressure to obtain powder crystals. The reaction solution after completion of the reaction was analyzed by HPLC, and as a result, it was confirmed that the reaction rate was 100%. After adding and stirring dichloroethane to the obtained powdery crystals, the crystals were filtered. This operation was repeated three times and dried under reduced pressure to obtain 2.58 g of powder crystals.
This powder was added with 5.62 g of a 1 kg ethanol solution in which 100 g of sodium hydroxide at 40 ° C. was dissolved, sodium chloride was removed by filtration, and the filtrate was collected. After adding 6.46g of formic acid aqueous solution which consists of formic acid / water = 10/90 (mass ratio) to this filtrate, it concentrated by an evaporator until it became 5g, and added 10g of water.
After repeating the concentration and the addition of 10 g of water three times, water was gradually added to adjust the dynamic viscosity to be 1.5 mm ² / s, which is designated as A-6.
Structural formula (R1, R2 and X) of the quaternary ammonium compound (A) in A-6 liquid confirmed by NMR was as showing in Table 1.

Production Example 7
The same procedure as in Preparation Example 6 was repeated, except that 4.5 g of trimethylamine and 3.21 g of 2- [2- (2-chloroethoxy) ethoxy] ethanol were used instead of 2- (2-chloroethoxy) ethanol. 3.10 g of powder crystals were obtained.
To this powder, 5.44 g of an ethanol solution of sodium hydroxide used in Production Example 6 and 6.26 g of a formic acid aqueous solution were subjected to sodium chloride filtration and concentration in the same manner as in Production Example 6, and water was gradually added The one adjusted to have a kinematic viscosity of 2.2 mm ² / s was designated A-7.
Structural formula (R1, R2 and X) of the quaternary ammonium compound (A) in A-7 liquid confirmed by NMR was as showing in Table 1.
Production Example 8
The procedure of Production Example 6 was repeated except that 5.8 g of triethylamine and 1.79 g of 2- (2-chloroethoxy) ethanol were used instead of trimethylamine to obtain 1.76 g of powder crystals.
To this powder, 3.11 g of an ethanol solution of sodium hydroxide used in Production Example 6 and 3.58 g of a formic acid aqueous solution were subjected to sodium chloride filtration and concentration in the same manner as in Production Example 6 and water was gradually added. The one adjusted to have a viscosity of 1.5 mm ² / s was designated as A-8.
The structural formulas (R1, R2 and X) of the quaternary ammonium compound (A) in solution A-8 confirmed by NMR were as shown in Table 1.

Production Example 9
The same as Production Example 6 except that 5.4 g of triethylamine was used instead of trimethylamine and 2.25 g of 2- [2- (2-chloroethoxy) ethoxy] ethanol was used instead of 2- (2-chloroethoxy) ethanol. To obtain 2.18 g of powder crystals.
To this powder, 3.24 g of an ethanol solution of sodium hydroxide used in Production Example 6 and 3.72 g of a formic acid aqueous solution were subjected to sodium chloride filtration and concentration in the same manner as in Production Example 6 and water was gradually added. The one adjusted to have a viscosity of 2.2 mm ² / s was designated as A-9.
The structural formulas (R1, R2 and X) of the quaternary ammonium compound (A) in solution A-9 confirmed by NMR were as shown in Table 1.
Production Example 10
Production Example 6 and Example 6 except that 4.0 g of trimethylamine and 3.60 g of 2- [2- [2- (2-chloroethoxy) ethoxy] ethoxy] ethanol were used instead of 2- (2-chloroethoxy) ethanol The same procedure was repeated to obtain 3.41 g of powder crystals.
To this powder, 5.02 g of an ethanol solution of sodium hydroxide used in Production Example 6 and 5.77 g of a formic acid aqueous solution were subjected to sodium chloride filtration and concentration in the same manner as in Production Example 6 and water was gradually added to What was adjusted so that a viscosity might be 3.5 mm < ² > / s was set to A-10.
The structural formulas (R1, R2 and X) of the quaternary ammonium compound (A) in solution A-10 confirmed by NMR were as shown in Table 1.
Production Example 11
Except that 5.0 g of triethylamine was used instead of trimethylamine, and 2.63 g of 2- [2- [2- (2-chloroethoxy) ethoxy] ethoxy] ethanol was used instead of 2- (2-chloroethoxy) ethanol, The procedure of Production Example 6 was repeated to obtain 2.50 g of powder crystals.
To this powder, 3.19 g of an ethanol solution of sodium hydroxide used in Production Example 6 and 3.67 g of a formic acid aqueous solution were subjected to sodium chloride filtration and concentration in the same manner as in Production Example 6 and water was gradually added. What adjusted so that a viscosity might be set to 3.7 mm2 / s was set to A-11.
The structural formulas (R1, R2 and X) of the quaternary ammonium compound (A) in solution A-11 identified by NMR were as shown in Table 1.

Production Example 12
The same procedure as in Production Example 1 was performed except that the kinematic viscosity was adjusted to 5.5 mm ² / s. This quaternary ammonium compound solution was named A-12.
Production Example 13
The same procedure as in Production Example 2 was repeated except that the kinematic viscosity was adjusted to 7.2 mm ² / s. This quaternary ammonium compound solution was named A-13.
Production Example 14
The same procedure as in Production Example 1 was carried out except that the kinematic viscosity was adjusted to 12.8 mm ² / s. This quaternary ammonium compound solution was named A-14.
Production Example 15
It carried out like manufacture example 2 except having adjusted kinematic viscosity to 13.9 mm < ² > / s. This quaternary ammonium compound solution was named A-15.
Production Example 16
The same procedure as in Production Example 7 was performed except that the kinematic viscosity was adjusted to 15.8 mm ² / s. This quaternary ammonium compound solution was named A-16.
The above production example was repeatedly performed according to the necessary amount.
In addition, when using the prepared quaternary ammonium compound solution, the nitrogen content was confirmed in advance with a trace total nitrogen analyzer TN-2100W.

<Quaternary ammonium compound (C) represented by formula (3)>
C-1: Choline acetate (manufactured by Aldrich) was dissolved in water, and the kinematic viscosity was adjusted to 1.5 mm ² / s C-2: Choline hydroxide (manufactured by Tama Chemical Co., Ltd.) was dissolved in water, the kinematic viscosity Was adjusted to 2.1 mm ² / s

<Method of producing crude polyacetal copolymer>
Jacketed twin-screw paddle type continuous polymerization reactor (2 mm in diameter, 2 inches, K (distance from the material supply port of the polymerization reactor to the discharge port) / D (in which the heat medium can be passed) The inner diameter of the polymerization reactor) = 14.8) was adjusted to 80 ° C.
Next, 0.10 g / hr of boron trifluoride-di-n-ethyl etherate as a polymerization catalyst, 6.00 g / hr of methylal as a low molecular weight acetal, 95.70 g / hr of diethylene glycol dimethyl ether, cyclic ether and / or cyclic Polymerization was carried out by continuously supplying 110.9 g / hr of 1,3-dioxolane and 3300 g / hr of trioxane as a formal to a polymerization reactor through a pipe to obtain a crude polyacetal copolymer (P-1).

[Examples 1 to 16 and Comparative Examples 1 to 3]
The crude polyacetal copolymer (P-1) was introduced into a 0.5% triethylamine solution to deactivate the polymerization catalyst. Thereafter, the solution is filtered and washed, and the quaternary ammonium compound solution prepared in each production example is added in such an amount that the nitrogen concentration n becomes as shown in Table 2 with respect to 100 parts by mass of the crude polyacetal copolymer (P-1). After being uniformly mixed, it was dried at 130 ° C.
With respect to 100 parts by mass of the crude polyacetal copolymer composition containing the quaternary ammonium compound (A) thus obtained, 0 of 2,2'-methylenebis- (4-methyl-t-butylphenol) as an antioxidant .2 parts by mass were added and fed to a vented twin screw extruder.
Water is optionally added to the molten crude polyacetal copolymer composition in the extruder, and the unstable terminal of the crude polyacetal copolymer at a set temperature of the extruder of 200 ° C. and a residence time of 5 minutes in the extruder. The department was disassembled. The cracked polyacetal copolymer at the unstable end was devolatilized under a vent vacuum of 20 Torr and extruded and pelletized as a strand from an extruder die.
Type of quaternary ammonium compound (A) used and amount used (content) of quaternary ammonium compound (A) based on total mass of polyacetal copolymer and quaternary ammonium compound (A) (fourth) (N concentration from n-class ammonium compound (A), water added to the extruder, addition amount of triethylamine with respect to 100 parts by mass of crude polyacetal copolymer composition, formaldehyde generated from the obtained polyacetal copolymer composition FA), amounts of acetaldehyde (AA) and acrolein (AL), powder color tone, odor upon molding, and molded piece color tone are summarized in Table 2.
Comparative Example 4
It carried out like Example 1 except not using a quaternary ammonium compound solution.

The results are shown in Table 2.

As shown in Table 2, in Examples 1 to 16, it is possible to obtain a polyacetal in which the color tone of the powder and the molded piece is excellent and the odor at molding is also small, and the polyacetal in which the generation of formaldehyde, acetaldehyde and acrolein is suppressed. Were obtained, and those excellent in color tone were obtained.
In Examples 12 and 13, the b value slightly increased because the polyacetal was colored because the kinematic viscosity of the quaternary ammonium compound solution used was high, and the color tone of the molded piece was slightly deteriorated accordingly. It is guessed.
On the other hand, in Comparative Examples 1 to 3, since the kinematic viscosity of the quaternary ammonium compound solution used was too high, the color tone of the powder was deteriorated, and a sweet smell was found at the time of molding. In addition, in Comparative Example 4, since the quaternary ammonium compound solution was not used, it was not possible to obtain a polyacetal in which the generation of formaldehyde, acetaldehyde and acrolein was suppressed.

  The quaternary ammonium compound solution of the present invention can be used for various applications, and in particular, can be effectively used to suppress the generation of volatile organic compounds from polyacetal.

Claims (7)

A quaternary ammonium compound solution which is a solution containing a quaternary ammonium compound (A) represented by the following formula (1), and whose dynamic viscosity at a water temperature of 15 ° C. is 0.4 to 10.0 mm ² / s .
[(R1) _m (R2) _4-m N ⁺ ] _n X ^n- (1)
(Wherein, R 1 is each independently a C 1 to C 30 unsubstituted alkyl group or a substituted alkyl group; a C 6 to C 20 aryl group; a C 1 to C 30 unsubstituted alkyl group or a substituted alkyl An aralkyl group in which the group is substituted with at least one aryl group having 6 to 20 carbon atoms; or an aryl group having 6 to 20 carbon atoms is at least one non-substituted alkyl group having 1 to 30 carbon atoms or a substituted alkyl group An unsubstituted alkyl group and a substituted alkyl group are linear, branched or cyclic, and the substituent of the substituted alkyl group is a halogen, a hydroxyl group, an aldehyde group, a carboxyl group, an amino group. The hydrogen atom of the unsubstituted alkyl group, the aryl group, the aralkyl group, and the alkylaryl group may be substituted with a halogen.
R2 each independently represents a group represented by the following formula, which has 2 to 60 carbon atoms and 2 to 30 oxygen atoms.
-(RO) k-H (wherein R represents a substituted or unsubstituted alkyl group and k represents a natural number of 2 or more).
m and n represent an integer of 1 to 3;
X is an acid residue of a compound selected from the group consisting of a hydroxyl group or a monocarboxylic acid having 1 to 20 carbon atoms, hydrogen acid, oxo acid, an inorganic thio acid and an organic thio acid having 1 to 20 carbon atoms, And a group not containing a nitrogen atom.   The quaternary ammonium compound solution according to claim 1, wherein X in the formula (1) is an acid residue of a monocarboxylic acid.   The quaternary ammonium compound solution according to claim 2, wherein the monocarboxylic acid is formic acid, acetic acid or propionic acid.   The quaternary ammonium compound solution according to any one of claims 1 to 3, which has 2 to 6 carbon atoms of R2 in the formula (1). The quaternary ammonium compound solution as described in any one of Claims 1-4 containing the quaternary ammonium compound (C) represented by following formula (3).
[R3R4R5R6N ⁺ ] _l Y ^l- (3)
(Wherein, R 3, R 4, R 5 and R 6 are each independently an unsubstituted alkyl group having 1 to 30 carbon atoms or a substituted alkyl group; an aryl group having 6 to 20 carbon atoms; an unsubstituted group having 1 to 30 carbon atoms An alkyl group or an aralkyl group in which a substituted alkyl group is substituted with at least one aryl group having 6 to 20 carbon atoms; or an aryl group having 6 to 20 carbon atoms has at least one unsubstituted alkyl group having 1 to 30 carbon atoms Or an alkylaryl group substituted with a substituted alkyl group, wherein the unsubstituted alkyl group and the substituted alkyl group are linear, branched or cyclic, and the substituent of the substituted alkyl group is a halogen, a hydroxyl group, an aldehyde group And a carboxyl group, an amino group or an amido group, and a hydrogen atom of the unsubstituted alkyl group, the aryl group, the aralkyl group and the alkylaryl group is substituted with a halogen It can have.
l represents an integer of 1 to 3;
Y represents an acid residue of a compound selected from the group consisting of a hydroxyl group or a carboxylic acid having 1 to 20 carbon atoms, a hydrogen acid, an oxo acid, an inorganic thio acid and an organic thio acid having 1 to 20 carbon atoms. )   The volatile organic compound generation inhibitor from polyacetal containing the quaternary ammonium compound solution as described in any one of Claims 1-5. A step of heat treating a polyacetal having a thermally unstable end portion to which the quaternary ammonium compound solution according to any one of claims 1 to 5 is added,
Method for producing polyacetal.