JPH1112354A - Production of polyphenylene ether and its composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject ether having a molecular weight distribution of two peaks by a continuous chain of polymerization and separating and purifying procedures in improved productivity, by joining polyphenylene ethers from a main line and a by-pass line and mixing. SOLUTION: (A) A polyphenylene ether having 0.4-3.0 dl/g reduced viscosity polymerized in a main polymerization line is combined and mixed with (B) a polyphenylene ether having 0.05-0.6 dl/g reduced viscosity bypassed from the main polymerization line in the weight ratio of the component A to the component B of 1:99 to 99:1 by a polymerization termination tank and the polymerization of the component A and the component B is terminated under conditions to make the reduced viscosity of the component A at least 0.1 dl/g higher than that of the component B. Preferably the polyphenylene ether is a poly(2,-6dimethyl-1,4-phenylene)ether and the continuous polymerization is carried out by a slurry polymerization in which the ether is partially precipitated during the polymerization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing polyphenylene ether utilizing the characteristics of a continuous polymerization method. More specifically, when oxidative polymerization of polyphenylene ether is performed by a continuous polymerization method, a line that partially bypasses the main polymerization line is provided, and the polyphenylene ether of the main line and the polyphenylene ether of the bypassed line are polymerized. Are combined in a polymerization stopping tank in a state in which polyphenylene ether having a bimodal molecular weight distribution is continuously and efficiently produced. Particularly, in combination with the slurry polymerization method, it has become possible to obtain a low-viscosity polyphenylene ether which has been difficult to operate stably until now. The polyphenylene ether thus obtained gives a thermoplastic resin composition having an excellent balance between mechanical properties and fluidity during molding when combined with a styrene resin or the like. In particular, it is possible to provide a molded article having excellent chemical resistance in spite of improving the fluidity at the time of molding in response to a demand for a thinner molded article.

[0002]

2. Description of the Related Art Conventionally, polyphenylene ether resin compositions are resins having excellent properties such as heat resistance, electrical properties, flame retardancy, acid resistance, alkali resistance and the like, and low specific gravity and low water absorption. However, when the molecular weight of the polyphenylene ether is reduced in order to increase the fluidity during melt molding, there is a disadvantage that the mechanical properties are deteriorated.

[0003] Japanese Patent Publication No. 4-500994 describes that a resin composition containing a mixture of two types of polyphenylene ethers having a specific solution viscosity has excellent fluidity during molding. However, this resin composition,
It is obtained by polymerizing two molecular weight polyphenylene ethers in a batch system, and simply blending the polyphenylene ethers after separation and purification. It is not advisable to take productivity into consideration. Also, U.S. Pat.
In the specification of Japanese Patent No. 806, a polyphenylene ether solution having two peak tops is obtained by GPC by subjecting a solution of polyphenylene ether obtained by complete batch polymerization to heat treatment after polymerization, but it produces a large amount of diphenoquinone as a by-product. Since this is a process and requires heat treatment after polymerization, this production method is not advisable in view of productivity.

As shown in Japanese Patent Publication No. 49-28919, it is very advantageous to carry out the production of polyphenylene ether by a continuous method of slurry polymerization in view of productivity. However, when producing low molecular weight polyphenylene ether, it was sometimes difficult to stably perform continuous operation.

[0005]

That is, an object of the present invention is to provide a polyphenylene ether resin composition having an excellent balance between mechanical properties and fluidity at the time of melt molding. An object of the present invention is to provide a method with improved productivity in which a polyphenylene ether can be continuously produced by a series of polymerization and separation and purification operations. Furthermore, the continuous polymerization of slurry enables the production of low-viscosity polyphenylene ether, which has been difficult to operate stably, and the resin composition obtained by this method has not only fluidity during melt molding but also mechanical properties. It is excellent.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, have reached the present invention. That is, the present invention relates to oxidative polymerization of polyphenylene ether,
In the continuous polymerization method, (a) a polyphenylene ether having a reduced viscosity of 0.4 dl / g to 3.0 dl / g polymerized in a main polymerization line and (b) a reduced viscosity of 0.1% which is bypassed from a main polymerization line. 05 dl / g-0.
A polyphenylene ether having 6 dl / g;
The polyphenylene ethers of (a) and (b) are combined and mixed in a polymerization stopping tank so that the weight ratio of the polyphenylene ethers is in the range of 1:99 to 99: 1, and the reduced viscosity of the polyphenylene ether of (a) is as shown in (b). Under the condition that at least 0.1 dl / g or more larger than the reduced viscosity of polyphenylene ether,
A method for producing a polyphenylene ether, wherein the polymerization of the components (a) and (b) is stopped.

According to this method, polyphenylene ether having a bimodal molecular weight distribution can be produced with high productivity in a form utilizing the characteristics of the continuous polymerization method. When the polyphenylene ether obtained by this method is used as a resin composition, a composition having an excellent balance between mechanical properties and fluidity during melt molding can be obtained. Hereinafter, the present invention will be described in detail.

[0008] The polyphenylene ether in the present invention is a polymer of a phenolic compound represented by the formula (1).

[0009]

Embedded image

(Wherein R3 represents an alkyl group, a substituted alkyl group, an aralkyl group, a substituted aralkyl group, an aryl group, a substituted aryl group, an alkoxy group, a substituted alkoxy group;
R4 may be halogen in addition to those defined for R3, and R5 may be hydrogen in addition to those defined for R4. Examples of such are, for example, 2,6-dimethylphenol, 2,2
3,6-trimethylphenol, 2-methyl-6-ethylphenol, 2,6-diethylphenol, 2-ethyl-6-n-propylphenol, 2-methyl-6-chlorophenol, 2-methyl-6-bromo Phenol,
2-methyl-6-isopropylphenol, 2-methyl-6-n-propylphenol, 2-ethyl-6-bromophenol, 2-methyl-6-n-butylphenol, 2,6-di-n-propylphenol, 2-ethyl-6-chlorophenol, 2-methyl-6-phenylphenol, 2,6-diphenylphenol, 2,6-bis- (4-fluorophenyl) phenol, 2-methyl-6-tolylphenol, 2, 6-ditolylphenol and the like. These phenolic compounds may be used alone or in combination of two or more. A small amount of phenol, o-cresol, m-cresol, p-cresol, 2,4-dimethylphenol,
-Even if ethylphenol or the like is contained, it does not matter substantially. Of these phenolic compounds, 2,6-dimethylphenol is particularly important. Polymerization of polyphenylene ether is performed by an oxidative polymerization method using oxygen, a catalyst and a solvent. As the oxygen, in addition to pure oxygen, a mixture of an inert gas with nitrogen or the like at an arbitrary ratio, air, or the like can be used. Examples of the catalyst include a catalyst system composed of a combination of a metal compound such as copper, manganese, or cobalt, which is known as a polymerization catalyst for polyphenylene ether, and an amine compound or the like as a cocatalyst.From the viewpoint of polymerization activity, a copper-amine catalyst is used. preferable.

The solvent is used in combination with a good solvent for polyphenylene ether and, if necessary, a poor solvent.
Examples of good solvents for polyphenylene ether include aromatic hydrocarbons such as benzene, toluene, ethylbenzene, o-xylene, m-xylene, and p-xylene;
Halogenated hydrocarbons such as methylene chloride, chloroform, 1,2-dichloroethane, chlorobenzene and dichlorobenzene, and nitro compounds such as nitrobenzene can be used. Examples of the poor solvent include alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol and tert-butanol; ketones such as acetone and methyl ethyl ketone; ethers such as diethyl ether; hexane;
Aliphatic hydrocarbons, such as cyclohexane, and even water can be used. One or more of these good solvents and, if necessary, one or more of poor solvents can be mixed and used.

In the present invention, the polymerization of polyphenylene ether is achieved by a continuous polymerization method. As disclosed in Japanese Patent Publication No. 49-28919, a continuous polymerization method of polyphenylene ether includes arranging a plurality of polymerization tanks in series, continuously supplying a monomer, a catalyst, a solvent, and the like to a first polymerization tank. This is a process in which a polymer can be continuously produced by sequentially polymerizing in a polymerization tank, and is excellent in productivity.

[0013] In the present invention, a high-molecular-weight polyphenylene ether produced in the main polymerization line and a low-molecular-weight polyphenylene ether from a line bypassed from the main polymerization line are supplied to a polymerization stop tank in a state of stopping the polymerization. It is characterized by merging with. In order to carry out the present invention, the main polymerization line needs to arrange two or more polymerization tanks in series. When using two polymerization tanks,
A high-molecular-weight polyphenylene ether obtained by continuously passing through two polymerization tanks; and a low-molecular-weight polyphenylene ether obtained by passing a part of the polyphenylene ether coming out of the first polymerization tank through a bypass line. Can be carried out in a polymerization stop tank. More preferably, three polymerization tanks are arranged in series. A desired low molecular weight polymer can be obtained by passing the polyphenylene ether from the first polymerization tank or the polyphenylene ether from the second polymerization tank through a bypass line. in this case,
By controlling the amount of polyphenylene ether passing through the bypass line per unit time, the composition ratio of high molecular weight and low molecular weight polyphenylene ether can be adjusted. In practice, this is performed by installing a liquid feed pump or the like capable of controlling the flow rate in the bypass line.

When a high molecular weight polyphenylene ether and a low molecular weight polyphenylene ether are combined under conditions that allow polymerization to proceed, a rearrangement reaction occurs between the polyphenylene ethers having different molecular weights, so that the difference between the two molecular weights is reduced and the physical properties are reduced. It is not preferable when considering the balance. Therefore, in the present invention, it is an essential condition that they are combined in a polymerization stopping tank. The state in which the polymerization is stopped means that either the supply of oxygen is stopped or the activity of the catalyst is lost, or the polymerization is performed at the same time. Instead of supplying oxygen, a method of supplying an inert gas such as nitrogen may be employed. As a method of losing the activity of the catalyst, for example, when a copper-amine catalyst is used, a method of coexisting a compound such as ethylenediaminetetraacetic acid is used. If necessary, a poor solvent for polyphenylene ether such as methanol can be added to the polymerization stopping tank. Thereby, polyphenylene ethers having two different molecular weights can be produced continuously and with high productivity.

When the polyphenylene ether having a bimodal molecular weight distribution obtained as described above is used as a resin composition, in order to balance mechanical properties and fluidity during melt molding, a high molecular weight Has a reduced viscosity of 0.4 dl / g to 3.0 dl / g, preferably 0.5 dl / g to 2.0 dl / g. The reduced viscosity of low molecular weight polyphenylene ether is 0.05 dl
/ G to 0.6 dl / g, preferably 0.06 dl / g to
0.4 dl / g. Furthermore, the difference in reduced viscosity between the high molecular weight polyphenylene ether and the low molecular weight polyphenylene ether is 0.1 dl / g or more, preferably 0.2 dl / g.
g or more. This is because if the difference in reduced viscosity is less than 0.1 dl / g, it is difficult to balance mechanical properties and fluidity, and the intended purpose cannot be achieved. The adjustment of the reduced viscosity is controlled by the amount of catalyst, the amount of supplied oxygen, the residence time of polymerization of polyphenylene ether, and the like. The weight ratio of high and low molecular weight components ranges from 1:99 to 99: 1. Preferably it is in the range of 90:10 to 10:90, most preferably in the range of 80:20 to 50:50.

The present invention can be applied to either a solution polymerization method in which polyphenylene ether is uniformly dissolved in a solvent or a slurry polymerization method in which a portion of the polyphenylene ether is precipitated during the polymerization. Whether the solution polymerization method or the slurry polymerization method is used depends on the polymerization solvent used. In the solution polymerization, as the polymerization proceeds, the molecular weight of the polyphenylene ether increases, and the viscosity of the solution increases. by this,
The solution polymerization method may not be suitable for the continuous polymerization method due to poor transportability of the polymer solution. As a more preferable embodiment, it is a method suitable for the present invention to employ a slurry polymerization method in which the viscosity of the liquid does not increase so much when the molecular weight of the polyphenylene ether increases, because a portion of the polyphenylene ether precipitates.

Furthermore, when the slurry polymerization method is used, the present production method has an advantage. In the continuous polymerization method of slurry polymerization,
When attempting to produce a low molecular weight polyphenylene ether, the viscosity fluctuated, and it was sometimes difficult to perform continuous operation at a controlled viscosity. According to the method of the present invention, since the molecular weight of the main polymerization line can be increased, stable operation with controlled viscosity can be performed. Further, by joining low molecular weight polyphenylene ether obtained from the bypass line in the polymerization stopping tank, it became possible to obtain polyphenylene ether having a low apparent viscosity. At this time, a poor solvent of polyphenylene ether such as methanol can be added to the polymerization stopping tank in order to stabilize the slurry state of polyphenylene ether. It is useful to apply the low-viscosity polyphenylene ether thus obtained to various thermoplastic resin compositions and the like. For example, a composition with a polystyrene resin or a polyamide resin. In particular, when a composition with a polystyrene resin is used, the apparent viscosity of the polyphenylene ether is low, so that not only the fluidity during melt molding is excellent, but also the mechanical properties represented by chemical resistance and the like are excellent. A composition can be obtained.

The composition using the polyphenylene ether obtained according to the present invention may contain other additives such as a plasticizer, a stabilizer, an ultraviolet absorber, a flame retardant, a colorant, a release agent, glass fiber, carbon fiber, and the like. A fibrous reinforcing agent such as fiber, and a filler such as glass beads, calcium carbonate, and talc can be added. As the stabilizer, phosphites, hindered phenols, sulfur-containing antioxidants, alkanolamines, acid amides, metal salts of dithiocarbamic acid, inorganic sulfides, metal oxides and the like alone or They can be used in combination. The constituent components may be mixed by any method, and for example, an extruder, a heating roll, a Banbury mixer, a kneader, or the like can be used.

[0019]

DETAILED DESCRIPTION OF THE INVENTION Next, the present invention is applied to poly (2,6-dimethyl-1,4-phenylene) ether, which is industrially important, and uses the polyphenylene ether obtained by the present invention. The properties of the polyphenylene ether / polystyrene resin composition will be described more specifically, but the present invention is not limited to these examples.

The measurement was performed under the following conditions. Reduced viscosity of polyphenylene ether (ηsp / c) Reduced viscosity was 0.5 g of polyphenylene ether in 10
A solution dissolved in 0 ml of chloroform was measured at 30 ° C. using an Ubbelohde viscosity tube and expressed in dl / g.

Molecular weight distribution of polyphenylene ether A calibration curve is prepared by gel permeation chromatography HL-802RTS manufactured by Toyo Soda Co., Ltd. using standard polystyrene and measured. Standard polystyrene has a molecular weight of 2
64, 364, 466, 568, 2800, 1670
Those having 0, 186000, and 1260000 are used.
The column is TSKgelG2500 manufactured by Toyo Soda Co., Ltd.
H _XL , TSKgelG3000H _XL , TSKgelG4
000H _XL and TSKgelG5000H _XL are used in series. The measurement was carried out at a solvent of chloroform, a solvent flow rate of 0.9 ml / min, and a column temperature of 40 ° C. The UV wavelength of the detector is 254n for standard polystyrene.
m, polyphenylene ether is measured at 283 nm.

The polyphenylene ether obtained in each of the Examples and Comparative Examples was prepared by preparing a resin composition by the following composition and manufacturing method, and comparing the fluidity and chemical resistance. 43.1 parts by weight of polyphenylene ether, 12.9 parts by weight of a homopolystyrene resin (Stylon 685, manufactured by Asahi Kasei Kogyo), 44.2 parts by weight of an impact-resistant polystyrene resin (Stylon 494, manufactured by Asahi Kasei Kogyo) and ZnO.
14 parts by weight, ZnS 0.14 parts by weight, Tris (2,4-
0.14 parts by weight of (di-t-butylphenyl) phosphite were mixed and mixed by a mixer, and then melt-kneaded and extruded with a 30 mm twin-screw extruder (PCM-30 manufactured by Ikegai Iron Works).
The strand was cut with a pelletizer to obtain a pellet-shaped resin composition. Using these pellets, the melt flow rate (MFR) was measured with a melt flow indexer. Further, the resin composition pellet is injected into an injection molding machine (TOSHIBA MACHINE IS-8).
0C) was used to measure the SSP when a dumbbell molded piece was prepared, and the resulting dumbbell molded product was used to measure chemical resistance. The conditions of each measurement item are as follows. (A) Measurement of fluidity MFR: 250 ° C., 1 according to ASTM / D1238
It was measured with a 0 kg load. (Unit: g / 10 min) SSP: The minimum gauge pressure required for forming an ASTM / D638 test piece was measured. Molding temperature 290 ° C, mold temperature 80 ° C (unit: kg / cm ² ) (b) Measurement of chemical resistance A test piece having a width of 4 mm, a thickness of 2.4 mm and a length of 20 mm was prepared, and this test piece was placed at the center. A half of the overhang is mounted horizontally on the gantry, a load of 560 g is applied to the overhanging side, and shaft grease is applied to the center of the test piece. The time until breaking was measured.

[0023]

EXAMPLE 1 A continuous polymerization reactor comprising three complete mixing tanks and a polymerization stopping tank were arranged in series, and the reactor and the polymerization stopping tank were connected by an overflow line. Further, as a bypass line for an overflow line coming out of the first polymerization machine, a line equipped with a fixed-quantity liquid supply pump was connected, and this line was directly inserted into the polymerization stop tank. The first reactor has a capacity of 1.5 l and is equipped with a circulation pump. The second reactor, the third reactor, and the polymerization stop tank have a stirrer, and the capacities are 3.7 l, 1.5 l, and 1.5 l, respectively. The first reactor, the second reactor, and the third reactor were provided with an oxygen supply port, and the polymerization stop tank was provided with a liquid supply port. The polymerization raw material solution was prepared by dissolving cupric chloride dihydrate, N, N, N ', N'-tetramethyl-1,3-diaminopropane and n-dibutylamine in methanol and further dissolving in xylene. , 6-dimethylphenol and butanol were adjusted. The composition of the polymerization raw material liquid is as follows. 2,6-
The concentration of dimethylphenol was 23% by weight, and the weight ratio of the solvent used was xylene: butanol: methanol = 55: 1.
5:30. 0.05 mol of copper atom equivalent, 0.46 mol of hydrochloric acid, 2.5 mol of N, N, N ', N'-tetramethyl-1,3-diaminopropane, n-mol per 100 mol of 2,6-dimethylphenol Dibutylamine 0.95
Is a mole.

The first reactor was charged with 11.6 g / m
in, and oxygen was supplied at 168 ml /
min. And the internal temperature was controlled to 40 ° C. A 30% amount of the polymerization liquid out of the polymerization liquid overflowing from the first reactor was controlled by a constant-quantity liquid sending pump so as to bypass the second and third reactors and directly enter the polymerization stopping tank. 5 for the polymerization liquid entering the second reactor
00 ml / min. Oxygen flow at the speed of 40 ℃
It controlled so that it might become. The polymer precipitates, but is uniformly distributed in the reactor by stirring. Further, 50 ml / min. Of oxygen was added to the polymerization liquid entering the third reactor.
And the internal temperature was controlled to 40 ° C. The polymerization liquid entering from the third reactor and the polymerization liquid entering from the bypass line were combined in a polymerization stopping tank. At the same time,
A 10% by weight aqueous solution of ethylenediaminetetraacetic acid / 3 potassium salt was added at 0.1 ml / min. And the polymerization was stopped. The reaction solution containing the polymer was continuously taken out by overflow from the polymerization stopping tank. Five times the volume of methanol was added to the polymerization solution, followed by filtration and washing with methanol three times.
This was vacuum-dried at 140 ° C. for 1 hour to obtain a polyphenylene ether powder. Ηsp / c of the obtained polyphenylene ether was 0.43 (variation R was 0.02). A part of the polymerization liquid discharged from the third reactor was sampled, and the polyphenylene ether obtained after separation, purification and drying had an ηsp / c of 0.58. Similarly, a part of the polymerization liquid passing through the bypass line was sampled, and the ηsp / c of the polyphenylene ether obtained after separation, purification and drying was 0.09. FIG. 1 shows the molecular weight distribution curve of the polyphenylene ether thus obtained by GPC measurement. Further, a resin composition was prepared by the above-described method, and fluidity and chemical resistance were evaluated. The results are shown in Table 1.

[0025]

FIG.

[0026]

COMPARATIVE EXAMPLE 1 By removing the bypass line from Example 1, the amount of copper in the catalyst was reduced to 0.03 mol in terms of copper atoms in order to obtain polyphenylene ether having the same ηsp / c as in Example 1 by the ordinary continuous polymerization method. However, the obtained polyphenylene ether varied over time in the range of ηsp / c of 0.38 to 0.45 (variation R was 0.07), and stable operation was difficult. . Ηsp / c of the obtained polyphenylene ether was 0.42. Further, a resin composition was prepared in the same manner as in the examples, and fluidity and chemical resistance were evaluated. The results are shown in Table 1.

[0027]

[Reference Comparative Example 1] Bypassing the bypass line from Example 1,
Polymerization was carried out by a usual continuous polymerization method with the amount of copper of the catalyst of Example 1 being 0.04 mol in terms of copper atoms. Ηsp / c of the obtained polyphenylene ether was 0.47. Further, a resin composition was prepared in the same manner as in Example 1, and fluidity and chemical resistance were evaluated. The results are shown in Table 1.

[0028]

[Table 1]

[0029]

According to the present invention, it is possible to obtain a polyphenylene ether resin composition having an excellent balance between mechanical properties and fluidity during melt molding by a method with good productivity utilizing the features of continuous polymerization. Can be. In particular, by combining with the slurry polymerization method, it became possible to produce a low molecular weight polyphenylene ether which was difficult with the continuous slurry polymerization method. More interestingly, the polyphenylene ether resin composition is excellent not only in fluidity but also in mechanical properties represented by chemical resistance.

[Brief description of the drawings]

FIG. 1 is the molecular weight distribution of the polyphenylene ether obtained in Example 1, the horizontal axis is the common logarithm of the molecular weight value (in terms of polystyrene), and the vertical axis is the differential molecular weight distribution value.

Claims (4)

[Claims] 1. When oxidative polymerization of polyphenylene ether is carried out by a continuous polymerization method, (a) polyphenylene ether having a reduced viscosity of 0.4 dl / g to 3.0 dl / g polymerized in a main polymerization line; Reduced viscosity of 0.05 dl / g to 0.6 dl bypassed from the polymerization line of
/ G of polyphenylene ether and the weight ratio of the polyphenylene ether of (a) and (b) is 1:99 to 99: 1.
(A)
The reduced viscosity of the polyphenylene ether of (b) is at least 0.1 dl
A method for producing a polyphenylene ether, wherein the polymerization of (a) and (b) is stopped under the condition that the amount becomes larger than / g. 2. The method for producing polyphenylene ether according to claim 1, wherein the continuous polymerization is carried out by slurry polymerization in which a part of the polyphenylene ether during the polymerization is precipitated. 3. The method according to claim 1, wherein the polyphenylene ether is poly (2,6).
The method for producing polyphenylene ether according to claim 1, wherein the compound is -dimethyl-1,4-phenylene) ether. 4. A resin composition containing polyphenylene ether obtained by using the method according to claim 1.