JPH01297428A - Polyphenylene ether copolymer - Google Patents

Abstract

PURPOSE:To obtain the subject novel copolymer containing a repeating unit substituted with a dialkylamino group in a specified ratio based on the main repeating unit and capable of remarkably improving coloration and viscosity increase in heat molding and suppressing foreign odor in molding, etc. CONSTITUTION:An objective copolymer with 50-1000 number-average polymerization degree having the main repeating unit of formula I (R1 is H, 1-4C alkyl or aryl) and another repeating unit of formula II [R2 and R3 are 1-20C (substituted)alkyl] in the main chain in an abundance ratio of the unit II >=the unit I/1000. In addition, 2,6-dimethylphenol is preferable as the monomer imparting the unit of formula I. Furthermore, the above mentioned copolymer is obtained, e.g., by adding a catalyst to a solution containing a phenol of formula III and a secondary aliphatic amine of formula IV and carrying out polymerization while supplying an oxygen-containing gas under vigorous stirring.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a novel polyphenylene ether copolymer. More specifically, the repeating unit (b) substituted with a dialkylamino group is 1/1000 of the main repeating unit (a).
The present invention relates to a polyphenylene ether copolymer whose main feature is that it contains the above.

[Conventional technology]

Polyphenylene ether is a resin with excellent heat resistance and mechanical properties, and is widely used as a molding material. In order to industrially produce this polyphenylene ether, a method is usually used in which substituted phenols are polymerized by oxidative coupling in the presence of a catalyst. Side reactions such as the oxidation of oxidation occur, and a heterogeneous structure is generally included. Therefore, there was a problem in that this heterogeneous structure had an undesirable effect on the polymer. Therefore, many proposals have been made to solve this problem, one of which is to improve the properties of polyphenylene ether by using an aliphatic secondary amine as a component of the polymerization catalyst. Yes (see Japanese Patent Application Laid-open No. 52-897).

[Problem to be solved by the invention]

In the above-mentioned time-opening method, the polyphenylene ether contains a structure formed by bonding an aliphatic secondary amine to the ortho benzyl position of the terminal hydroxyl group of the polymer (structure (C) described below), which improves mechanical properties etc. However, during melt molding, the aliphatic secondary amine bond structure thermally decomposes, producing low molecular weight amines and their derivatives. As a result of remaining in molded products, a new problem has arisen: unpleasant odors during molding. This is a problem that is particularly important in application fields where odor is important, such as food containers for microwave ovens, and in application fields where hot water extracts are a problem, and improvement has been desired.

(Means for Solving the Problems) As a result of research conducted by the present inventors to solve the above problems, the structure of general formula (b) in which the bonding position of the aliphatic secondary amine is a benzyl position other than the terminal In the case of , there is almost no decomposition during melt molding, so there are no problems such as odor, and the color tone is equal to or better than that of a structure in which a secondary amine is bonded to the terminal benzyl position (structure (C) described below). We discovered that there is, and arrived at the present invention.

That is, the present invention has a main repeating unit represented by the general formula (a) defined in the above claim and a repeating unit represented by the general formula (b) in the main chain, and (a) and (b) The present invention provides a polyphenylene ether copolymer having an abundance ratio of (b)≧(a)/1000F and a number average degree of polymerization of 50 to 1ooo.

In the above, (a) or (
b) Units should be bonded, and it is better to avoid direct bonding of H atoms.

In the polyphenylene ether copolymer of the present invention,
The repeating unit represented by general formula (b) is the main repeating unit (
It is necessary to include 0.1 or more per 100 a). Although there is no particular upper limit, it is preferably 5 or less per C(a)too pieces. In addition, although the coexistence of other heterogeneous structures to the same degree as those present in polymers obtained by known polyphenylene ether production techniques is not prohibited, it is preferable to keep the amount as small as possible.

In particular, the following terminal structure (C) with aliphatic secondary amine bonded
should be kept to a small amount.

This is because the structure (e) is thought to liberate the amine upon heating during molding, etc., through the reaction shown in the following formula.

This amine not only causes an unpleasant odor, but also becomes a component that can be extracted by solvents and hot water, and also causes coloration.

The main repeating unit in the polyphenylene ether copolymer composition mixture of the present invention is represented by the general formula (a), and any phenylene ether group known to be copolymerized with this is added in the total amount. It may be contained in 1/2 or less of (a).

The degree of polymerization is preferably in the number average range of 50 to 1000,
When expressed in number average molecular weight, when R=CH3, it is approximately 6,000 to 1
It is 20,000. In particular, those having a number average degree of polymerization of 100 to 300 are preferred for use as ensearing resins.

The number average degree of polymerization of the present invention is determined by calculating the number average molecular weight in terms of polystyrene determined by gel permeation chromatography of the main repeating unit (a), as specifically shown in the [Example] section below. Substitution (for example, if R=CH3, 1
20.2).

The repeating unit (a) preferably has a methyl group at its 2nd and/or 6th position. Representative examples of monomers corresponding to these include 0-cresol, 2.6-dimethylphenol, 2.3.6-dimethylphenol, 2-
Examples include methyl 6-phenylphenol, and in the present invention, these may coexist with each other or with a small amount of 2,6-diphenylphenol. Among these, 2,6-dimethylphenol is particularly preferred.

The secondary aliphatic amine corresponding to the di-substituted amino group in the repeating unit (b) has the formula (d) HNR2R3...(d) [In the formula, R and R3 are each singly or both non-cyclic. and a cyclic organic group]. Preferred secondary aliphatic amines are those in which R2 and R3 each have 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms. Especially since it is now commercially readily available, R
Secondary aliphatic amines in which 2 and R3 are each C1, preferably C1, more preferably C3-5 alkyl groups are preferred.

Specific examples of secondary amines are shown below.

Dimethylamine, diethylamine, di-n-propylamine, di-secondary propylamine, di-n-butylamine, di-secondary-butylamine, di-tertiary-butylamine, dibenzylamines, diethylamines, diethylamines, dioctyl Amines, dinonylamines,
didecylamines, dioctylamines, dibenzylamines, methylethylamine, methylbutylamines,
Methylcyclohexylamine, heptylcyclohexylamine, octadecylcyclohexylamine, etc.

In the terminal structure (C), even if substituents with some function were selected for R2 and R3, they would decompose and separate from the polymer during heat molding, so it was rarely effective.
It has been found that the repeating 2 unit (b) does not decompose even when heated, so it can be used to impart various functions. for example,
An excellent composition can be developed by introducing into R2°R3 a functional group that has good adhesion with fillers or a group that is compatible with other resins. For this purpose, dialkanolamines are particularly preferred examples of secondary amines.

The method for producing the polyphenylene ether copolymer of the present invention is not particularly limited, but for example, in the presence of a secondary aliphatic amine represented by the general formula (f), a method similar to the known oxidative coupling polymerization of phenols may be used. It can be manufactured using That is, a catalyst and, if necessary, a co-catalyst are added to a solution containing a phenol represented by the general formula (e) and a secondary aliphatic amine represented by the general formula (f), and the oxygen-containing solution is stirred vigorously. Polymerization is performed by supplying gas.

(Left below) In this production method, the structure (C) in which a secondary amine is bonded to the terminal group is first formed in the initial stage of polymerization, and then a polymer chain grows from the terminal hydroxyl group to form the repeating unit (b). Become.

If the conventional polymerization method is applied as is, the polymerization reactivity of the terminal group (d) is significantly lower than that of a normal non-aminated terminal group, so most of the terminal group remains as it is. Repeating unit (b) is the main repeating unit (a)
However, it was not possible to generate more than 1/1000 liters. As a result of the inventors' intensive search for a method for efficiently reacting the terminal group to which the secondary amine is bonded, the following three methods were found to be effective. One of them is to make the polymerization temperature as high as possible. Especially the terminal structure (C)
The purpose is to raise the polymerization temperature during the middle stage of the reaction, when the formation of the polymer has almost finished and the polymerization reaction is actively progressing. Another method is to increase the monomer concentration in the late stage of the reaction (approximately 80% to 95% hydroxyl group addition rate).

Another method is to use a highly active catalyst. Catalysts that have high activity especially at high temperatures are limited. Special request 1976
An example of this is the catalyst used in the method for producing polyphenylene ether shown in Japanese Patent No. 2-77570. Note that increasing the amount of secondary amine used did not have much effect. There are no particular restrictions on the post-treatment method after the reaction is completed.

Usually, after deactivating the catalyst by adding an acid such as hydrochloric acid or acetic acid to the reaction solution, the resulting polymer is separated, washed with a solvent that does not dissolve the polymer such as methanol, and then dried. Polyphenylene ether can be recovered by operation.

The polyphenylene ether copolymer obtained by this method has a much larger amount of repeating units (b) than those obtained by conventional polymerization in the presence of an aliphatic secondary amine, and the purpose of the present invention is to It satisfies the requirements. Furthermore, although the number of secondary amine bond terminals (e) is considerably reduced compared to conventional polymers, further reduction may be necessary depending on the application.

There are two methods that are effective in such cases. One is to eliminate relatively low molecular weight portions of the polymer mixture. Since the terminal structure (C) is a structure in which the polymer does not grow on the hydroxyl group side after it is formed in the initial stage of polymerization, it naturally exists in large quantities in the low molecular weight range. This tendency is particularly remarkable when the polymer is polymerized while being precipitated. Typically, if a low molecular weight region of about 5% by weight is removed by dissolution and reprecipitation, the terminal group (
About 30 to 40% of C) is removed, and only 5 to 10% of repeating unit (b) is removed. If it is necessary to remove the terminal group (C) more completely, a second method is to decompose it by heating in advance. Specifically, a method of removing the liberated amine by reducing pressure while melting or after melting, a method of removing the liberated amine by extraction after melting and cooling, and a method of removing the liberated amine by extraction after melting the polymer, or a slurry in which a part of the polymer is precipitated. There is a method in which the polymer is heated in such a state, and then the polymer is precipitated and separated from the liberated amine.

〔Effect of the invention〕

Compared to conventional polyphenylene ether, the polyphenylene ether copolymer of the present invention has significantly improved coloring and viscosity increase during heat molding, and eliminates unpleasant odors during molding and use without impairing other properties. It is a copolymer that has the excellent property of being able to suppress

[Examples] Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples. In addition, each measurement was performed under the following conditions.

■ The viscosity of the polymer is 0.5% chloroform solution at 30%
It was measured using an Ubbelohde viscosity tube under the following conditions. ηsp
It was expressed as /c.

■ The molded product was made by mixing powders obtained in Examples and Comparative Examples with 31%
Refers to a test piece molded under heat and pressure at 0°C and 180 kg/c♂ for 10 minutes.

△η/η is the value obtained by dividing the difference in ηsp/c between the powder and the molded product by the powder's ηsp/c, and is used as an index of the increase in viscosity during hot molding.

(2) The degree of coloring was evaluated by dissolving 0.5 g of the molded product in chloroform to make a total volume of 10 ml, measuring the absorbance at 480 nm at 25° C., and using the color index defined by the following formula.

Here: 1゜ Intensity of incident light 1 : Intensity of transmitted light a : Cell length (cm) b : Solution concentration (g/cm") ■ The total nitrogen bond amount of polyphenylene ether is JIS
It was measured according to the microkeltal method of K2609.

■1H-nuclear magnetic resonance vector is GX- manufactured by JEOL ■
270 using CD0g3 as a solvent.

■ Gel permeation chromatography (hereinafter referred to as G
PC) is Toyo Soda Kogyo ■HL-802)? Measured with TS and calibrated with standard polystyrene.

Example 1 Polymerization was carried out using a continuous polymerization reactor consisting of three complete mixing tanks. The first reactor has a capacity of 1.5Ω and is equipped with a circulation pump. The second reactor and the third reactor are equipped with a stirrer and have a capacity of 3.7Ω and 1.5g, respectively.

The catalyst solution was prepared by dissolving cuprous oxide in 35% hydrochloric acid, adding methanol, and then di-n-butylamine, N, N, N', N
Adjustment was made by adding '-tetramethyl-J,3-diaminopropane and methanol. A monomer liquid was prepared by dissolving 2,6-dimethylphenol in mixed xylene and n-butanol. Each was prepared under air.

Catalyst liquid and monomer liquid were fed to the second reactor, and methanol was fed to the second reactor at a constant rate.

Based on the amounts of the catalyst liquid and monomer liquid fed, the composition of the reaction raw material liquid is as follows.

The polymerization ratio of the solvent used was 2.6-dimethylphenol at a concentration of 20% by weight: mixed xylene:n-butanol:methanol=80:20:20. However, the half metal of methanol was sent to the second reactor.

2.6-dimethylphenol per 100 moles, copper is 0.
06 gram atom, CΩ ion is 0.55 gram atom, di-n-butylamine is 1.5 mole, N, N, N', N'
-tetramethyl-1,3-diaminopropane in a proportion of 3 moles. Also, 2,6-dimethylphenol is 1
It was fed at a rate of 60 g/Ilr.

In the first reactor, the reaction solution was vigorously circulated using a circulation pump, and oxygen was passed through the reactor. The internal temperature was controlled to be 40°C. The reaction liquid sent from the first reactor to the second reactor under head pressure was homogeneous.

While stirring vigorously in the second reactor, oxygen gas was pumped for 500 m
It was kept at 35°C by flowing at a rate of 1/min. Although the polymer precipitates, it is uniformly distributed throughout the reactor due to stirring. As an overflow from the second reactor, the reaction solution containing polymer particles enters the third reactor.

While controlling the temperature of the third reactor at 25° C. and stirring with a stirrer, oxygen gas was flowed at a rate of 200 ml/min.

A reaction solution containing a polymer was continuously taken out from the third reactor as an overflow.

Methanol was added to the yellow-white reaction liquid containing the slurry, and the mixture was filtered. It was thoroughly purified and washed using a mixed solvent (mixed xylene, butanol, and methanol) and diluted hydrochloric acid. The viscosity (ηsp/c) of the polymer obtained after drying was 0.66±
It was within the range of 0.03, and stable operation was possible for a long period of time.

The results of structural analysis and physical property evaluation of the obtained copolymer are shown in the table.
1.

Comparative Example 1 In Example 1, the amounts of copper and hydrochloric acid were changed to 0.05 gram atom and 0.46 gram atom, di-n-butylamine was not added, and 2,6-dimethylphenol was pumped. The same procedure as in Example 1 was performed except that the amount was changed to 172 g/Ilr, and the results shown in Table 1 were obtained.

Comparative Example 2 For comparison, a catalyst with low polymerization activity was used as follows. That is, in Example 1, copper was changed to 0.09 gram atom, hydrochloric acid was changed to 0.83 gram atom of hydrobromic acid, and N,N,N',N'-tetramethyldiaminopropane was changed to butyldimethylamine. Change to 1.8 mol and further N
, 0.18 mol of N'-di-t-butylethylenediamine was newly added. In addition, the liquid feeding port for 2,6-dimethylphenol was changed to 240 g/Hr, and the temperature of the second reactor was changed to 25 g/Hr.
The temperature was changed to ℃ and the same procedure was performed to obtain the results shown in Table 1.

(Confirmation of Polymer Structure) The structures of the copolymers of Examples 1 and 2 and Comparative Examples 1 and 2 were determined mainly by nitrogen elemental analysis and nuclear magnetic resonance spectroscopy.

The terminal group (C) to which the secondary aliphatic amine was bonded was confirmed and quantified by IH and 13C nuclear magnetic resonance spectroscopy. That is,
On the 1H nuclear magnetic resonance spectrum of Example 1, a signal of the methylene group of formula (C) was observed at 3.63 ppm,
n-butyl group -CHCH2CH2 corresponding to R and R5
The signals corresponding to the four types of 1H nuclei of CHs are 2.47
．． It was observed at 1.50°, 1.29° and 0.88 ppm, and the area intensity ratio was also consistent with the structure of formula (C). The structure of formula (C) was quantified based on this area intensity, and for the polymer of Example 1, it was confirmed to be 0.20% of (a). These signals were also observed on the spectrum of the copolymer of Comparative Example 2, and were determined to be 0.30% of (a), but they were not observed at all on the spectrum of the copolymer of Comparative Example 1. . In addition, the copolymer R of Example 1 and Comparative Example 2
The signals of the four 13C-nuclei of the n-butyl group in 5 are 13
Observed between ~53 ppm.

Structure (b), in which an aliphatic secondary amine is bonded to the benzyl position in the main chain, gives a ``H nuclear magnetic resonance spectrum very similar to the structure of formula (C), but the chemical shift values of each signal are determined by the formula ( It can be clearly distinguished from that of C), and the methylene group signal is 3.36 I) l) II+, and the two terminal signals of the n-butyl group are 1.17 ppm and 0.80 ppm.
observed at m. This structure existed in the polymer of Example 1 at 0.13% of (a), but it did not exist at all in the polymer of Comparative Example 1, and in the polymer of Comparative Example 2 ( a) 0
．． 0.02% or less was present.

The difference in the bonding positions of these two types of secondary aliphatic amine bonding structures was clarified as follows. When the low molecular weight was removed from the polymer of Example 1 by reprecipitation and recovery with methanol from a toluene solution, the signal assigned to formula (C) decreased from 0.20 mol% to 0.11 mol%. However, the signal assigned to formula (b) hardly decreased. In the low molecular weight region of 5%, the signal assigned to (C) was unevenly distributed at 1.7 mol%, but the signal assigned to formula (b
) was hardly enriched.

It is a typical feature of the terminal group that it is unevenly distributed in the low molecular weight region, and the structures of formula (b) and formula (C) were determined based on this.

The presence of the main repeating unit (a) was confirmed by 1H-magnetic resonance spectrum and other measurements.

Table 1 ×Strong odor Example 2 In Example 1, copper, hydrochloric acid, and N, N, N', N'
The amount of -tetramethyl-1,3-diaminopropane was 0.
05 gram atom, 0.46 gram atom, and 2.5 mol, and the amount of 2,6-dimethylphenol sent was 172 gram atom.
g/Ilr and the temperature of the second reactor to 45 °C.
A copolymer was obtained in the same manner as in Example 1 except that the temperature of the third reactor was changed to 40°C. The viscosity of the obtained copolymer was η=0.57. This copolymer contains 0.18 (b) for every 100 main repeating units (a),
The presence of 0.30 (C) was confirmed by 1H-nuclear magnetic resonance spectrum. This copolymer was heated at 250°C for 20
When analyzed again after pressurizing and heating molding for a minute, (b) showed almost no decrease at 0.16 pieces per 100 pieces of (a), but (C) was not observed at all. N instead,
Although N-dibutylamine and the like were observed, these could be almost completely removed by the dissolution and reprecipitation operation. In the end it included
A copolymer containing only (b) as the structure was obtained.

Claims (1)

[Claims] 1. Having a main repeating unit represented by the following general formula (a) and a repeating unit represented by the general formula (b) in the main chain, and the presence of (a) and (b) The ratio is (b)≧(a)/1000
A polyphenylene ether copolymer having a number average degree of polymerization of 50 to 1000. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(a) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(b) (In the formula, R_1 is hydrogen, an alkyl group with 1 to 4 carbon atoms, or aryl group, R_2 and R_3 are the same or different alkyl groups or substituted alkyl groups having 1 to 20 carbon atoms)