KR20080073722A - Method for the preparation of a poly(arylene ether), and related compositions - Google Patents

Abstract

A method for preparing a poly(arylene ether) with a reduced level of powder fines is described. In one embodiment, the method comprises oxidatively coupling a monohydric phenol in the presence of a solvent and a complex metal catalyst, to produce a poly(arylene ether) resin; and then removing a portion of the solvent to produce a concentrated solution having a cloud point Tcloud. The concentrated solution is then combined with an anti-solvent to precipitate the poly(arylene ether) in the form of a precipitation mixture. The concentrated solution usually has a temperature of at least about (Tcloud-10°C) immediately before it is combined with the anti-solvent. The precipitation mixture has a temperature of at least about: (Tcloud-40°C) after its formation. Related poly(arylene ether) copolymers are also described.

Description

Method for the Preparation of a Poly (arylene ether), and Related Compositions}

The present invention relates generally to synthetic resins. More specifically, it relates to methods of making poly (arylene ether) polymers useful for high temperature applications.

Poly (arylene ether) resins are commercially useful materials because of their inherent combination of physical, chemical and electrical properties. The resins are generally characterized as having a desirable combination of hydrolysis stability, good dimensional stability, toughness, heat resistance and dielectric properties. They also exhibit high glass transition temperature values (Tg), typically in the range of about 150 ° C-215 ° C, as well as very good mechanical performance.

Polyphenylene ether (PPE) resins based on poly (arylene ether) are often used in admixture with other polymers to further enhance the properties of the ultimate polymer product. For example, PPE resins are often mixed with polyamides. The molded articles produced above exhibit the most desirable properties of each material, for example, good heat and dimensional stability from PPE, and good strength and chemical resistance from polyamide. End uses for which this type of structural material is applied include computer housings, automotive panels, and the like.

Recently, it has been desirable to further increase the high-temperature capability of materials such as poly (arylene ether) / polyamide blends. For example, automotive panels made of such materials need to withstand relatively high paint oven temperatures when coating parts. One means of increasing the high temperature capability is to apply the desired copolymer to the poly (arylene ether) component. For example, European Patent Application 627,466 discloses the preparation of poly (arylene ether) copolymers of 2,6-dimethylphenol and 2,3,6-trimethylphenol. Copolymers of this type are often characterized by having relatively high Tg values, for example in the range of about 225 ° C to about 230 ° C.

Various methods of preparing and isolating poly (arylene ether) homopolymers and copolymers are known in the art. Many methods are described in the background section of US Pat. No. 6,407,200 to P. Singh et al. One well-established method of separating the polymers involves mixing the polymerization mixture with an antisolvent such as methanol and then filtering the precipitate produced.

Many different techniques have been developed over the years regarding the general techniques of sedimentation and filtration. For example, the aforementioned European application discloses the separation of poly (arylene ether) copolymers by reverse-precipitation with acetone, and filtration. Another technique also includes a pre-concentration step in which some of the reaction solvent is removed before the settling step.

Next, the separated polymer is subjected to additional, conventional processing steps. For example, the polymer can sometimes be re-slurrified with an antisolvent, filtered again and then washed with additional solvent. Conventional solid / liquid separation techniques include filtration, solid bowl centrifuges, gravity settling, and the like. After this additional step, the polymer is usually dried by various methods. For example, drying may be performed at elevated temperatures, under atmospheric pressure or under reduced pressure, of various types of industrial drying equipment, such as pneumatic conveying dryers, screw-conveying dryers, or fluidized bed dryers. can be carried out using a fluid bed dryer. The product made in powder form is then moved to another location for storage or mixing. In large commercial plants, transport is often done by air systems, via pipe networks.

The aforementioned processes are often suitable for efficiently producing a desired poly (arylene ether) product in high yield. However, there are some disadvantages to the above processes. For example, the poly (arylene ether) powders produced by these techniques can sometimes contain a high proportion of undesirable powder “fines”. As used herein, the term “microparticles” means solid particles having a particle size of less than about 38 microns (micrometers).

Microparticles can cause various problems during processing of the polymer. Their presence may be associated with the loss of poly (arylene ether) during the filtration and drying steps. Microparticles tend to stick to process line filters, which can clog movement and cause excessive pressure drop. (The filtration pressure drop can give rise to a warning to stop powder transfer from the conveying line, for example from the resin silo to the silos present in the mixing zone). In general, the presence of many fine powder particles makes it difficult to efficiently separate the polymer powder from the gas in drying and conveying systems, causing the accumulation of fine particles in the vent system, and blowing dust into the air. There is a possibility. Removing fine particles from the filter is difficult and time consuming. Moreover, the presence of microparticles can create a dust explosion hazard when powder-handling involves contact with air, requiring the installation of expensive safety devices.

In addition to transport and flow issues, the presence of microparticles can also cause serious problems during extrusion and molding of the polymer product. For example, although they constitute part of a solid powder composition, the fine particles often do not have the minimum solid mass and density required for proper flow into and through the extruder. Thus, when too many fine particles are present, an appropriate shearing force for extruding the polymer product may not be obtained.

With these concerns, there have been attempts to reduce the level of microparticles in solid polymer products such as poly (arylene ether) materials. One strategy for this involves changing the processing conditions under which the polymer product is made. For example, previously referenced US Pat. No. 6,407,200 discloses a process for preparing poly (arylene ether) wherein a portion of the reaction solvent is removed after a redox step with a catalyst. Due to the removal of the solvent portion, a concentrated solution of the polymer product remains. This solution can then be mixed with the antisolvent to precipitate the desired polymer product, as mentioned above. In connection with the cited patent, the inventors have found that if the temperature of the concentrated solution rises to a certain level just before mixing with the antisolvent, it is possible to reduce the production of unwanted microparticles.

U.S. Patent No. 6,407,200 discloses significant innovations in poly (arylene ether) production and processing, particularly in the area of fine particle reduction. However, further improvements in this technical area have also been of great interest, especially in the present era when there is a demand for higher product yields and product quality. Thus, there remains a need for an improved process for producing poly (arylene ether).

New processes should lead to a greater reduction in microparticle content in powder products and to improvements in powder flow kinetics. The processes should also be compatible with the preparation of the above-mentioned high temperature poly (arylene ether) copolymers, which are in great demand today. Moreover, the process should be economically suitable for large scale manufacturing facilities, for example, without significant changes in plant structure or process requirements. Moreover, the overall properties of the article molded from the polymeric material must be substantially maintained.

Brief Description of the Invention

A method of making poly (arylene ether) is disclosed. In one embodiment, the method

(a) oxidatively coupling the monovalent phenol in the presence of a solvent and a complex metal catalyst to produce a poly (arylene ether) resin;

(b) removing a portion of the solvent to prepare a concentrate having a cloud point T cloud ; And

(c) mixing the concentrate with an anti-solvent to settle the poly (arylene ether) in the form of a settling mixture;

The concentrate has a temperature just before mixing with the antisolvent is about (T cloud -10 ° C) or higher;

The settling mixture has a temperature after formation of about (T cloud -40 ° C) or more.

Another embodiment relates to a poly (arylene ether) copolymer powder comprising 2,6-dimethyl-1,4-phenylene ether units and 2,3,6-trimethyl-1,4-phenylene ether units . The copolymers usually have an intrinsic viscosity of about 0.25 dL / g to about 0.5 dL / g and comprise less than about 18 weight percent of particles less than about 38 micrometers.

Specific descriptions of various features of the invention may be found in the rest of the specification.

Brief description of the drawings

1 is a graph showing the percentage of powder microparticles as a function of temperature parameter in a polymer settling experiment.

2 is a graph showing polymer particle size as a function of settling mixture temperature.

Detailed description of the invention

In terms of general structure, poly (arylene ether) polymers that can be prepared and processed according to the present invention are known in the art. Many are US Patent Publication Nos. 3,306,874; 3,306,875; 3,306,875; And 3,432,469 (Hay); US Patent Publication No. 4,806,602 to White et al; U.S. Patent Publication No. 4,806,297 to Brown et al; U.S. Patent No. 5,294,654 to Hellstern-Burnell et al; And US Pat. No. 6,407,200 (Singh et al), all of which are incorporated herein by reference. Such polymers are generally prepared by oxidative coupling of monohydric phenols and using an oxygen-comprising gas in the presence of a solvent and a complex metal catalyst.

The monohydric phenol comprises one or more structural units of the formula

Wherein each Q ¹ is independently halogen, C ₁ -C ₇ primary or secondary alkyl, phenyl, C ₁ -C ₇ haloalkyl, C ₁ -C ₇ aminoalkyl, C ₁ -C ₇ hydrocarbonoxy And C ₂ -C ₇ halo hydrocarbonoxy wherein at least two carbon atoms separate halogen and oxygen atoms; Each Q ² is independently hydrogen, halogen, C ₁ -C ₇ primary or secondary alkyl, phenyl, C ₁ -C ₇ haloalkyl, C ₁ -C ₇ aminoalkyl, C ₁ -C ₇ hydrocarbonoxy, And C ₂ -C ₇ halo hydrocarbonoxy wherein at least two carbon atoms separate halogen and oxygen atoms.

In some preferred embodiments, the monohydric phenol comprises 2,6-dimethylphenol (DMP) and 2,3,6-trimethylphenol (TMP). do. The DMP and TMP may be used in any ratio, the weight ratio may be 99: 1 to 1:99. However, it is often desirable to use a DMP / TMP with a weight ratio of about 1 : 1 to about 20 : 1. For oxidative coupling of the monohydric phenol, oxygen-comprising gases such as oxygen or air are typically used, with oxygen being preferred.

As mentioned above, the monohydric phenol is oxidatively coupled in the presence of a solvent. Various solvents can be applied. Examples of suitable solvents include aliphatic alcohols, ketones, aliphatic and aromatic hydrocarbons; Chlorohydrocarbons, nitrohydrocarbons, ethers, esters, amides, mixed ether-esters, sulfoxides, etc. may be included, but are not limited thereto. Combinations comprising at least one of the above solvents may also be used if they do not interfere with or do not participate in the oxidation reaction. In a preferred embodiment, the solvent may comprise C ₆ -C ₁₈ aromatic hydrocarbons including, for example, toluene, xylene and the like and mixtures thereof. Very preferred solvent is toluene. (Hereinafter, the term "solvent" means defining a single solvent or a mixture of two or more solvents together.)

In some embodiments, the solvent further comprises one or more aliphatic alcohols in which the poly (arylene ether) is poorly soluble. Examples may include C ₃ -C ₈ aliphatic alcohols, such as n-propanol, isopropanol, n-butanol, t-butanol, n-pentanol, and the like; Combinations comprising at least one of the aliphatic alcohols may be included, but are not limited thereto. Preferred alcohols of this type are n-butanol. The solvent may further comprise methanol or ethanol, which acts as an antisolvent for the poly (arylene ether).

The C ₆ -C ₁₈ aromatic hydrocarbons, C ₃ -C ₈ aliphatic alcohols and methanol or ethanol may be mixed in various ratios. However, sometimes it is preferred that the solvent comprises at least about 50% by weight of C ₆ -C ₁₈ aromatic hydrocarbons. In a particularly preferred embodiment, the solvent comprises at least about 75% by weight of C ₆ -C ₁₈ aromatic hydrocarbons.

As mentioned above, the oxidative coupling reaction can be carried out in the presence of a complex metal catalyst. Catalysts of this type are known in the art. US Patent No. 6,407,200; 3,306,875; 3,306,875; US Patent No. 5,068,310, as well as 3,306,874 cited above; 4,755,566; And 4,092,294, which are incorporated by reference.

The complex metal catalyst system generally includes metal ions, such as ions of group VIB, VIIB, VIII or IB, on the periodic table, and combinations thereof. Of these, chromium ions, manganese ions, cobalt ions, copper ions, and combinations comprising one or more of these ions may be preferred, but copper ions (Cu + and Cu ++) are very preferred.

The complex metal catalyst system may further comprise a nitrogen-containing ligand. The nitrogen-containing ligands include, for example, alkylenediamine ligands, primary monoamines, secondary monoamines, tertiary monoamines, aminoalcohols, oxines, and at least one of the nitrogen-containing ligands. Combinations and the like.

Various specific examples of nitrogen-comprising ligands are disclosed in the above cited patents, such as US Pat. No. 6,407,200. Examples of alkylenediamine ligands may include, but are not limited to, N, N'-di-t-butylethylenediamine and N, N, N ', N'-tetramethyl-1,3-diaminopropane. . The primary monoamine may be n-butylamine, sec-butylamine, and cyclohexylamine, and n-butylamine may be very preferred, but is not limited thereto. Examples of secondary amines may include di-n-propylamine, di-n-butylamine, and di-t-butylamine, with di-n-butylamine often being preferred, but not limited thereto. Examples of the tertiary amine may include triethylamine, dimethyl-n-butylamine, and various cyclic tertiary amines, and dimethyl-n-butylamine may be very preferred, but is not limited thereto. Examples of suitable aminoalcohols may include, but are not limited to, N, N-diethylethanolamine, triethanolamine and N-phenylethanolamine. Examples of the auxin may include, but are not limited to, auxin and 5-methyloxine. Various combinations of these amines and compositions comprising such combinations may also be used.

If most of the aforementioned vaginal-comprising ligands are present, they may be used at about 0.01 to about 25 moles per 100 moles of monohydric phenol. The tertiary monoamine may be used at about 0.1 to about 1500 moles per 100 moles of monohydric phenol. Within this range, the selection of the appropriate concentration may be apparent to those skilled in the art without undue experimentation. The concentration chosen may reflect the presence of other reaction elements or products, such as water, that can affect catalyst efficiency. Suitable molar ratio of complex metal catalyst to phenol (measured as moles of metal) is about 1: 400 and about 1: 50 to about 1 100 to about 1: 200 is often preferred.

The complex metal catalyst system optionally further comprises halide ions such as chloride, bromide or iodide. When halide ions are applied, the reaction mixture may be provided in the form of an alkali metal salt or alkaline earth metal salt at a concentration of about 0.1 mole to about 150 moles per 100 moles of phenol monomer.

In a preferred embodiment, the complex metal catalyst comprises copper ions, secondary alkylenediamine ligands, secondary monoamines, and tertiary monoamines. In a very preferred embodiment, the complex metal catalyst comprises copper ions, N, N'-di-t-butylethylenediamine, di-n-butylamine, and dimethyl-n-butylamine.

Various techniques can be used to initially prepare poly (arylene ether). In very general terms, the reaction vessel can first be filled with other conventional components, such as reaction solvents, some of the poly (arylene ether) monomers, complex metal catalysts and surfactants and the like. Thereafter, a flow of oxygen or oxygen-comprising gas may be introduced into the reaction vessel while the remainder of the poly (arylene ether) monomer is added over a period of time. The order and schedule for monomer addition can vary widely. The polymerization can then be carried out until a polymer with the desired molecular weight is obtained. As will be appreciated by those skilled in the art, the polymerization can be carried out in a bulk process or in a continuous process.

Polymerization process conditions such as reaction time, temperature, oxygen flow rate, and the like can be modified based on the desired molecular weight and monomer composition. The end point of the polymerization can be conveniently determined with an in-line viscosity meter. Other procedures can also be performed during the process. Examples may include molecular weight measurements, run at predetermined reaction times, and control of specific end group concentrations.

The temperature maintained during the polymerization step can vary widely, for example from about 0 ° C to about 95 ° C. Within this range, the polymerization temperature is often at least about 25 ° C., with a preferred maximum temperature of about 55 ° C. At temperatures substantially higher than about 95 ° C., side reactions may occur, leading to side product formation reactions. At temperatures substantially below about 0 ° C., ice crystals may form in the solution.

The polymerization process may further include recovering the complex metal catalyst in an aqueous solution. As disclosed in, and incorporated by reference, US Pat. Nos. 6,407,200 and 3,838,102, various extractant or chelating agents may be used to complex with the catalyst after the polymerization reaction is over. . When such materials are added to the poly (arylene ether) reaction solution, the complex metal catalyst is contaminated, so that no further oxidation occurs.

The extraction solvent and chelating agent may include, but are not limited to, sulfuric acid, acetic acid, ammonium salts, bisulfate salts, and various polyfunctional carboxylic acid containing compounds. In one embodiment, preferred chelating agents include ethylenediaminetetraacetic acid (EDTA) or nitrilotriacetic acid (NTA), or various salts of these materials. Mixtures containing individual extraction solvents or chelating agents may also be applied. Furthermore, as disclosed in US Pat. No. 6,407,200, the chelated metal catalyst can be extracted using a liquid / liquid centrifuge with water produced in the polymerization reaction. Often alcohols or water / alcohol mixtures can be used as extracts.

The polymerization medium may comprise a water soluble environment. As disclosed in US Pat. No. 6,407,200, antisolvents can be used in admixture with water soluble media and assist in inducing settling of copper (I) species. The antisolvent used in this step can often be low molecular weight aliphatic and aromatic hydrocarbons, ketones, alcohols and the like. Those skilled in the art will be able to select the type of antisolvent and the amount of antisolvent most suitable for the polymerization step.

In a preferred embodiment of the present invention, part of the reaction solvent can be removed after the polymerization of the poly (arylene ether) to prepare a concentrate. This concentration step, sometimes referred to as "pre-concentration", is often performed after the removal of the complex metal catalyst. In examples where the poly (arylene ether) is based on monovalent phenols such as DMP and TMP, the concentrate has a cloud point "T cloud ". (As discussed below, sometimes homopolymers also exhibit cloud points).

The cloud point T cloud is a property of the polymer solution and is a function of polymer concentration and molecular weight. T cloud corresponds to the temperature at which turbidity is observed for the first time in a cooling solution of poly (arylene ether). The T cloud is influenced by various factors, such as the monomer composition, intrinsic viscosity and concentration of the poly (arylene ether), as well as the nature of the solvent applied. Specific methods for determining T cloud in a given reaction system are disclosed in US Pat. No. 6,407,200. Briefly, the T cloud value for a given poly (arylene ether) dissolved in a particular solvent can be determined by preparing the solution in a homogeneous state and then gradually decreasing the temperature until turbidity is first observed. By measuring the T cloud values by varying the poly (arylene ether) monomer composition, intrinsic viscosity and concentration, in poly (arylene ether) / solvent systems, it is possible to derive the T cloud relation for these variables.

The above-mentioned preconcentration step is carried out to produce a concentrate having about 20 to about 60% by weight of poly (arylene ether). However, determining the assumed appropriate poly (arylene ether) level depends on various factors, such as the type of solvent used and the inherent viscosity of the poly (arylene ether). In one embodiment, the minimum concentration is preferably at least about 25% by weight, more preferably at least about 30% by weight. In one embodiment, the maximum concentration is preferably about 55% by weight, and more preferably about 50% by weight. In a particularly preferred embodiment, the maximum weight percent is about 45 weight percent.

In connection with the aforementioned T cloud measurement, the preconcentration step is often carried out at a temperature of about (T cloud - 10 ° C) or higher, preferably at a temperature of about (T cloud - 5 ° C) or higher. In a more preferred embodiment, the temperature is at least about (T cloud ), or at least about (T cloud + 5 ° C). In a very preferred embodiment, the temperature is at least about (T cloud + 10 ° C).

Any suitable method for total concentration may be applied. For example, the preconcentration may be carried out by pre-heating the reaction solution at a temperature above the boiling point in the atmosphere, at an appropriately elevated pressure above about 1 atmosphere. (In this way, no boiling occurs in a typical heat exchanger). The solution is then suddenly evaporated to lower pressures and temperatures, so that a significant portion of the solvent evaporates. The required heat-of-vaporization is supplied by the heat transferred in the heat exchanger, such as the heat of the solution that can be sensed.

The process of the present invention further comprises mixing the concentrate with an antisolvent to settle the poly (arylene ether). The concentrate is preferably at least about (T cloud - 10 ° C) at a temperature just before mixing with the antisolvent. As disclosed in US Pat. No. 6,407,200, this specific temperature characteristic of the concentrate results in a reduction of microparticles. In a more preferred embodiment, the concentrate is preferably at this stage the temperature just before mixing with the antisolvent is about (T cloud - 5 ° C.) or more. However, as disclosed in US Pat. No. 6,407,200, even higher temperatures may be used in certain cases. For example, a particularly preferred temperature is T cloud , and sometimes a temperature of (T cloud + 5 ° C.) can be applied. In certain cases the most preferred temperature is (T cloud + 10 ° C).

As mentioned above, the temperature of the concentrate is specified according to the time just before mixing with the antisolvent. In the context "directly" means a specific temperature when mixed with an antisolvent. As a practical method, the temperature of the concentrate can be measured at any time within about 30 seconds after mixing with the antisolvent. Another way of expressing temperature limits is to remove a portion of the solvent to produce a concentrate having a cloud point T cloud , adjust the temperature of the concentrate to about (T cloud - 10 ° C.) or higher, and mix the concentrate with an antisolvent. Thus, it can be said to be a process including the precipitation of poly (arylene ether).

In a preferred embodiment, the concentrate is T cloud It has a higher temperature and is homogeneous just before mixing with the antisolvent. The homogeneity of the solution means that no turbidity is present in the solution and can be determined by the same visual observation technique applied for the T cloud measurement. In a particularly preferred embodiment, a temperature above about (T cloud + 5 ° C.) may be maintained in the poly (arylene ether) -comprising solution from the beginning of the concentration step, just before the prepared concentrate is mixed with the antisolvent . .

In one embodiment, the temperature of the concentrate is at least about 60 ° C, preferably at least about 70 ° C. More preferably, the temperature is at least about 80 ° C, most preferably at least about 90 ° C. It should be noted that solutions of homopolymer poly (2,6-dimethyl-1,4-phenylene ether) in aromatic solvents such as toluene show no cloud point, except at relatively very low temperatures where possible. When the homopolymer solution is concentrated, it may be to form a gelatinous phase without clouding which is a separate solid particle characteristic).

Various antisolvents can be mixed with the concentrate to precipitate the poly (arylene ether). Examples include alcohols having 1 to about 10 carbon atoms, such as methanol; Ketones having 3 to about 10 carbon atoms, such as acetone and the like; And alkanes having about 5 to about 10 carbon atoms such as hexane and the like, but are not limited thereto. Combinations comprising at least one of the above antisolvents may also be applied. Preferred antisolvents can include methanol, such as, for example, a solvent mixture comprising at least about 50% by weight methanol (ie, "methanol-based").

In many embodiments, highly preferred antisolvents comprise about 70 to about 100 weight percent methanol; 0 to about 20 weight percent toluene, and 0 to about 10 weight percent water. The antisolvent may be applied in an amount relative to the amount of the organic solvent, in an optimum amount depending on the characteristics of the organic solvent and the antisolvent, as well as the concentration, the intrinsic viscosity and the monomer composition of the poly (arylene ether) product. . For example, the poly (arylene ether) has an intrinsic viscosity of 0.36 dL / g, about 82% by weight of 2,6-dimethyl-1,4-phenylene ether units and about 18% by weight of 2,3, Random copolymer, having a composition consisting of 6-trimethyl-1,4-phenylene ether units; The organic solvent is toluene; The antisolvent is methanol, and the toluene / methanol weight ratio may be suitable from about 1 : 1.5 to about 1 : 5.

The precipitate mixture formed when the antisolvent is mixed with the concentrate should have a temperature of about (T cloud -40 ° C.) or higher after formation. As used herein, "after formation" generally refers to a particular temperature during which the antisolvent is mixed with the concentrate. As a practical matter, the temperature of the settling mixture can generally be determined at any time within about 5 minutes, beginning with the step of mixing the antisolvent with the concentrate.

In many preferred embodiments, the settling mixture may have a temperature of about (T cloud -30 ° C) or higher after formation, and more preferably, a temperature of about (T cloud -20 ° C) or higher after formation. In one embodiment, the settling mixture has a temperature of about T cloud or more after formation. In large scale situations, however, the maximum temperature of the settling mixture is about 2 ° C.-3 ° C. below the boiling point of the solvent mixture, which may occur if, at some large scale, the solvent and antisolvent begin to evaporate. Because of the things.

However, in other embodiments, for example, if the solids content of the poly (arylene ether) in the concentrate is less than normal (eg, in the range of about 15% to about 25% by weight), the temperature of the settling mixture is about It can be as high as (T cloud + 10 ℃). In such cases, measures may need to be taken to control solvent and antisolvent losses. For example, the settling system (or region thereof) can be performed under pressure.

As further described below, the inventors have found that due to the increase in the settling mixture temperature (compared to conventional methods), a large reduction in the level of microparticles can be derived. Other techniques may be useful for bringing and maintaining the temperature of the settling mixture to a predetermined level. For example, when the mixture is formed, conventional equipment may be used to heat the settling mixture in the settling vessel.

However, in a preferred embodiment, the temperature of the preferred settling mixture is obtained by introducing an antisolvent at the selected temperature. Appropriate temperatures for the antisolvent may be determined by a variety of well known factors: the nature of the reaction solvent and the antisolvent, the specific heat value of each solvent applied; Volume ratio of the poly (arylene ether) concentrate to the volume of the antisolvent; Concentration of polymer in solution; And the molecular weight of the polymer. One skilled in the art can select the most appropriate antisolvent temperature based on these factors and empirical observation in a given settling system. One embodiment is as follows, but not limited thereto: When the temperature of the selected settling mixture is about (T cloud -40 ° C), the antisolvent is about (T cloud - 45 ° C) just before mixing with the concentrate. ) To about (T cloud - 50 ° C) or more.

For simplicity, for a typical process for the preparation of poly (arylene ether) copolymers, an example of a settling mixture temperature may be provided, but is not limited thereto (more on this example below). In larger scale processes using toluene or xylene based solvents and methanol based solvents, wherein the solid concentration in the concentrate is from about 35% to 41% by weight, the precipitated mixture has a temperature of at least about 44 ° C after it is formed. Can be. In a preferred embodiment, the settling mixture temperature may be at least about 48 ° C. In a particularly preferred embodiment, the settling mixture has a temperature of about 51 ° C. or higher.

Various types of equipment can be used to perform the settling step. For example, sedimentation can be performed in a stirred tank vessel or a high shear impeller. Suitable high shear impellers are for example commercially available from Wilhelm Siefer GmbH & Co., Velbert, Germany. The shear rate during sedimentation in the stirred tank and high shear homogenizer can be from about 500 sec ⁻¹ to about 50,000 sec ⁻¹ . Those skilled in chemical engineering are very familiar with other details regarding sedimentation operation.

As a rule, the precipitated poly (arylene ether) is then separated using conventional filtration or solid / liquid separation techniques. Suitable filtration devices include rotating filters, continuous rotary vacuum filters, continuous moving bed filters, batch filters, and the like. Suitable solid / liquid separation devices include continuous solid / liquid centrifuges.

The filtered poly (arylene ether) is then washed generally using conventional techniques. Washing can be performed, for example, using an additional antisolvent directly on the filter. Alternatively, the "powder wetcake" of the filter or solid / liquid separation device may be mixed with additional antisolvent in a stirred tank.

A preferred method of washing the filtered poly (arylene ether) is to use two stage reslurry and solid / liquid separation treatment techniques. In this embodiment, the wet cake of the filter may be washed with antisolvent in a stirred tank. The poly (arylene ether) / solvent / antisolvent mixture is then followed. Can be separated in a solid / liquid continuous centrifuge. After separation in the centrifuge, the poly (arylene ether) wet cake is mixed with the antisolvent for the second time in a continuous stirred tank, followed by a second solid / liquid separation in a second solid / liquid centrifuge Can be.

As mentioned above, the precipitated poly (arylene ether) is characterized by a reduction in the level of fine particles, as a result of the treatment mentioned here. In general, the level of microparticles (ie, those less than 38 microns in size) is less than about 18 weight percent, more preferably less than about 15 weight percent. In one particularly specific embodiment, the level of microparticles is less than about 12% by weight. As mentioned earlier, this type of poly (arylene ether) powder flows more freely (ie, has a higher flow index) than powders with higher amounts of microparticles. As a result, the powder causes much less substantial movement problems, such as, for example, problems with filters with impeded movement. During the further processing process (eg mixing and molding), other potential problems can also be reduced or eliminated.

The inherent viscosity of the poly (arylene ether) formed by the process described herein can vary widely. In some applications, it may be desirable to use poly (arylene ether) having an intrinsic viscosity of at least about 0.20 dL / g, more preferably at least about 0.25 dL / g, as measured in 25 ° C. chloroform. In a particularly preferred embodiment, the intrinsic viscosity is at least about 0.30 dL / g.

Exemplary methods for preparing poly (arylene ether) copolymers are described below. Exemplary copolymers are based on a combination of 2,6-dimethylphenol and 2,3,6-trimethylphenol (as mentioned earlier, this type of copolymer is often characterized by having a relatively high Tg value). ). The process uses 2,6-dimethylphenol and 2,3,6-trimethylphenol using an oxygen-comprising gas in the presence of a complex copper catalyst and a solvent system comprising toluene and xylene or toluene / xylene mixtures. By oxidatively coupling the poly (arylene ether) copolymer resin. Then, a portion of the solvent is removed, to provide a concentrate having a cloud point T cloud . The concentrate is then mixed with an antisolvent to precipitate the poly (arylene ether). In a preferred embodiment, the concentrate has a temperature T just before mixing with the antisolvent. As disclosed in US Pat. No. 6,407,200, T satisfies the following inequality.

T ( [Φ s-(0.296 x IV + 1.27 x TMP -35.7 ] /

[ 1.97 (1-0.00795 x IV -0.0249 x TMP ] -10 ) ,

Where Φ s is the polymer concentration (expressed in weight percent), IV is the intrinsic viscosity of the copolymer in 25 ° C. chloroform (expressed in mL / g), and TMP is the 2,3,6-trimethylphenol content in the polymer ( Expressed in weight percent). Moreover, in this embodiment, the settling mixture, which is formed when the antisolvent is mixed with the concentrate, has a temperature of about (Tcloud-40 ° C.) or higher.

In another exemplary embodiment, a process for preparing poly (arylene ether) comprises: using an oxygen-comprising gas in the presence of a complex copper catalyst and a solvent system comprising toluene, xylene or toluene / xylene mixture, Oxidatively coupling 2,6-dimethylphenol and 2,3,6-trimethylphenol to prepare a poly (arylene ether) copolymer resin; The weight ratio of 2,6-dimethylphenol to 2,3,6-trimethylphenol is about 3: 1 to about 6: 1; Recovering the complex metal catalyst in an aqueous solution; Removing a portion of the solvent to produce a concentrate comprising about 30 to about 45 weight percent poly (arylene ether) copolymer resin and having a cloud point T cloud ; And mixing the concentrate with a methanol-based antisolvent to precipitate the poly (arylene ether) in the form of a settling mixture. In this exemplary embodiment, the concentrate is about (T cloud) just before mixing with the antisolvent. + 5 ° C.); After the sedimentation mixture is formed, it has a temperature of about (T cloud -40 ° C) or more. The precipitated poly (arylene ether) has an intrinsic viscosity of about 0.25 to about 0.50 dL / g.

In one exemplary embodiment, a method of making a poly (arylene ether) comprises: using an oxygen-comprising gas in the presence of a complex copper catalyst and a solvent system comprising a toluene, xylene or toluene / xylene mixture. And oxidatively coupling 2,6-dimethylphenol and 2,3,6-trimethylphenol to prepare a poly (arylene ether) copolymer resin, wherein the 2,6-dimethylphenol and 2,3,6 The weight ratio of trimethylphenol is from about 3: 1 to about 6: 1; Recovering the complex metal catalyst in an aqueous solution; Removing a portion of the solvent to prepare a solution having about 30 to about 45 weight percent poly (arylene ether); And mixing the concentrate with a methanol-based antisolvent to precipitate the poly (arylene ether). In this embodiment, the concentrate has a temperature of at least about 80 ° C. immediately before mixing with the antisolvent; After the sedimentation mixture is formed, it has a temperature of about 44 ° C. or higher. The precipitated poly (arylene ether) has an inherent viscosity of about 0.25 to about 0.50 dL / g.

One embodiment relates to a composition of matter, often in powder form. The composition, as mentioned above, comprises poly (arylene ether) in powder form. In a preferred embodiment, the poly (arylene ether) is an air comprising both 2,6-dimethyl-1,4-phenylene ether units and 2,3,6-trimethyl-1,4-phenylene ether units It is coalescing. The weight ratio of said 2,6-dimethyl-1,4-phenylene ether units and 2,3,6-trimethyl-1,4-phenylene ether units is often from about 1 : 1 to about 20 : 1. In a particularly preferred embodiment, the weight ratio of the 2,6-dimethyl-1,4-phenylene ether unit and the 2,3,6-trimethyl-1,4-phenylene ether unit is about 3 : 1 to about 6 : 1 to be. The copolymer often has a Tg of about 220 ° C. or more. An important feature of this composition is that, as mentioned above, the level of microparticles is minimized. Thermoplastic compositions based on the poly (arylene ether) materials described herein represent another embodiment of the present invention. Embodiments may include, but are not limited to, polyphenylene ether / polyamide blends.

Example

The following examples described below illustrate various embodiments, but are not limited thereto.

Example 1

This example is a general description of the synthesis and separation of poly (arylene ether) copolymers. (The temperature of the settling mixture in this example was below the temperature specified for the present invention). The copolymer had repeating units derived from 18% by weight of 2,3,6-trimethylphenol and units derived from 82% by weight of 2,6-dimethylphenol. The reactor contains cuprous oxide (Cu ₂ O; 0.027 kg, dissolved in Ametican Chemet) dissolved in hydrobromic acid (0.423 kg in 48% aqueous solution, CAS Reg. No. 10035-10-6, prepared from Great Lakes). made of copper); N, N'-di-t-butylethylenediamine (0.119 kg, prepared from DBEDA, CAS Reg. No. 4062-60-6 Celanese); Di-n-butylamine (1.616 kg, DBA, CAS Reg. No. 111-92-2, prepared from Celanese); N, N-dimethylbutylamine (2.675 kg, DMBA, CAS Reg. No. 927-62-8, prepared from Celanese); Tetraalkylammonium chloride surfactant (0.059 kg, CAS Reg. No. 5137-55-3, manufactured by Aliquat from Cognis); 2,6-dimethylphenol (5.361 kg), and toluene solvent (140.06 kg) were mixed. During the polymerization reaction, additionally 2,6-dimethylphenol (30.377 kg) was added along with 2,3,6-trimethylphenol (7.845 kg).

During the polymerization, the nitrogen flow rate was 61.3 liters / minute; Oxygen flow rate was 46.2 liters / minute; The temperature gradually increased from 29.4 ° C. to 55.0 ° C. After completion of the polymerization reaction, the copper catalyst was separated from the polymer by mixing the reactor effluent with an aqueous nitrilotriacetic acid solution (0.871 kg in 60% solution in water, prepared from CAS Reg. No. 139-13-9, Solutia). . Using a liquid-liquid centrifuge, the biphasic-solution was separated. The polymer phase was concentrated to 38% by weight of polymer by sudden evaporation of toluene at atmospheric pressure. The copolymer product was precipitated from the concentrated polymer solution by mixing the solution (88 ° C.) and methanol (15 ° C.) in a stirred tank vessel such that the polymer solution: methanol was at a 1: 2 weight / weight ratio. The prepared slurry was passed through a rotary vacuum filter, and the wet cake was reslurried with methanol. The slurry was centrifuged and the separated solid particles were dried in a rotary paddle dryer.

Example 2

This example demonstrates the effect of two parameters on the production of microparticles during the sedimentation process. (As mentioned earlier, the fine particles are particles less than 38 microns). Two parameters are: (1) concentrate temperature, and (2) settling mixture temperature. In this embodiment, the "sedimentation mixture temperature" parameter is expressed in relation to the antisolvent temperature. (As mentioned earlier, increasing the antisolvent temperature is a preferred technique for increasing the settling mixture temperature).

The method of Example 1 was used to prepare a poly (arylene ether) random copolymer having an intrinsic viscosity of 39.6 mL / g and having 18.3% by weight of TMP derived repeat units. The separated powder copolymer sample was then dissolved in toluene to yield a 20 wt% solution. Settling was performed batch-wise in a stirred vessel provided with a high shear mixer and operated at a rotational speed of 15,000 rpm to perform high shear mixing. At the beginning of the experiment, an antisolvent was present in the vessel. The antisolvent included 78.1 wt% methanol, 19.4 wt% toluene and 2.5 wt% water. A solution of poly (arylene ether) in toluene at a solid concentration of 20% by weight was then added to the container in 2 minutes such that the poly (arylene ether) / toluene solution for the antisolvent had a weight / weight ratio of 1 : 3. .

Sample A constituted one “run” of a mixture of concentrate (20 wt% poly (arylene ether)) and antisolvent. In this sample, the temperature of the poly (arylene ether) / toluene solution added to the methanol antisolvent was 47 ° C., which was designated as a relatively “low” temperature. The temperature of the methanol antisolvent was 40 degreeC just before mixing with a concentrate. This antisolvent temperature was also designated relatively "low temperature". The resulting temperature of the settling mixture after formation was about 43-46 ° C.

Sample B constituted another segment during mixing of the concentrate of the poly (arylene ether) and the antisolvent. In this sample, the temperature of the poly (arylene ether) / toluene solution added to the methanol antisolvent was 72 ° C., which was designated as a relatively “high” temperature. The temperature of the methanol antisolvent was the same (“low”) as sample A, ie 40 ° C. The resulting temperature of the settling mixture after formation was about 48 ° C.

Sample C constituted another segment during mixing of the concentrate of the poly (arylene ether) and the antisolvent. In this sample, the temperature of the poly (arylene ether) / toluene solution added to the methanol antisolvent was 72 ° C., as in Sample B, ie the relatively “high” temperature. The temperature of the methanol antisolvent was about 62-64 degreeC just before mixing with a concentrate. This antisolvent temperature was designated as a relatively "high" temperature (compared to sample B). The sedimentation mixture temperature after formation was about 61-64 ° C.

The settling mixture temperature was kept constant during the settling step. The precipitated copolymer was then filtered through a paper for Schliccher and Schull "Black Ribbon" filters on Buchner filters, during which vacuum was applied. After filtration, the remaining filter-cake was washed with 1,200 grams of methanol. The washed filter cake was then dried at 125 ° C. for about 4 hours in a vacuum oven.

In each example, the particle size distribution of the precipitated copolymer was measured using a PSD Analyzer manufactured by Malvern Instruments Ltd., which applied a laser diffraction technique that divided the particles into six size classes: Less than micrometer, 38-63 micrometer, 63-125 micrometer, 125-425 micrometer, 425-710 micrometer, and greater than 710 micrometer.

1 shows the percentage of microparticles as a function of temperature parameters for the concentrate and settling mixture (ie, antisolvent temperature). Sample A (“cold-cold”) maintained these two temperature parameters at relatively low levels and showed significant concentrations of microparticles, ie, about 32% by weight. In sample B ("hot-low temperature") the temperature of the concentrate rose and there was a noticeable decrease in the content of fine particles (up to about 27% by weight). This reduction in microparticle content is based on the invention in US Pat. No. 6,407,200.

Sample C (“hot-hot”) is based on the teachings of the present invention and includes an increase in both concentrate temperature and antisolvent temperature. As shown in FIG. 1, Sample C exhibits a significant reduction in microparticle content when compared to Sample A and Sample B. FIG. The content of microparticles was reduced to about 5% by weight or less.

Example  3

The method of Example 1 was again used to produce a poly (arylene ether) random copolymer having an intrinsic viscosity of 38 mL / g and having 18% by weight of TMP derived repeat units. The separated powder copolymer sample was then dissolved in toluene, resulting in a 38% by weight solution.

In this experiment, the settling step was performed using a concentrated polymer phase (38 wt% polymer in toluene) and methanol antisolvent, according to the general procedure outlined in Example 2. In each series of samples, the temperature of the concentrate was kept constant at about 90 ° C. before mixing with the antisolvent. However, the temperature of the settling mixture in these samples varied from about 43 ° C. to about 51 ° C. (The settling mixture temperature varied with the temperature change of the introduced antisolvent).

2 is a graph showing polymer particle size as a function of settling mixture temperature. Particle size was measured in-line, using conventional laser based techniques. Such measurements include powder analysis in a liquid based sedimentation mixture. The measurement was performed before the selected step of the process, in this example before the filtration and drying steps. Moreover, it has already been determined that a strong correlation exists between the in-line measured average particle size and the percentage of fine particles in the final dried powder. For example, an in-line measurement (Y-axis, FIG. 2) of 23 microns corresponds to less than about 12% microparticle content in the dried powder.

The data, which are the basis of FIG. 2, demonstrated that the increase in sediment-mixture temperature generally results in a linear increase in average particle size (dashed line). Increasing the average particle size, together with the previously mentioned desirable effects, reduces the amount of fine particles present in the final polymer product.

The invention has been described according to embodiments and examples. However, those skilled in the art can make various modifications, adaptations, and replacements without departing from the present invention. All patents, documents and text mentioned above are incorporated herein by reference.

Claims (34)

As a method for producing a poly (arylene ether), (a) oxidatively coupling monovalent phenol in the presence of a solvent and a complex metal catalyst to produce a poly (arylene ether) resin; (b) removing a portion of the solvent to prepare a concentrate having a cloud point T cloud ; And (c) mixing the concentrate with an anti-solvent to settle the poly (arylene ether) in the form of a settling mixture; The concentrate has a temperature just before mixing with the antisolvent is about (T cloud -10 ° C) or higher; The settling mixture is a method of producing a poly (arylene ether), characterized in that the temperature after molding is about (T cloud -40 ℃) or more. The method of claim 1, wherein the monohydric phenol comprises one or more structural units represented by the following formula.

, Wherein each Q ¹ is independently halogen, C ₁ -C ₇ primary or secondary alkyl, phenyl, C ₁ -C ₇ haloalkyl, C ₁ -C ₇ aminoalkyl, C ₁ -C ₇ hydrocarbonoxy And C ₂ -C ₇ halo hydrocarbonoxy wherein at least two carbon atoms separate halogen and oxygen atoms; Each Q ² is independently hydrogen, halogen, C ₁ -C ₇ primary or secondary alkyl, phenyl, C ₁ -C ₇ haloalkyl, C ₁ -C ₇ hydrocarbonoxy, and at least two carbon atoms are It is selected from the group consisting of C ₂ -C ₇ halo hydrocarbonoxy to separate oxygen atoms. The method of claim 1, wherein the monohydric phenol comprises 2,6-dimethylphenol and 2,3,6-trimethylphenol. 4. The preparation of poly (arylene ether) according to claim 3, wherein the weight ratio of 2,6-dimethylphenol and 2,3,6-trimethylphenol is in the range of about 1 : 1 to about 20 : 1. Way. The method of claim 1 wherein the concentrate comprises about 20 to about 60 weight percent poly (arylene ether). The method of claim 1, wherein the precipitation mixture has a temperature after molding of about (T cloud -30 ° C.) or more. The method of claim 1, wherein the sedimentation mixture has a temperature after molding of about (T cloud -20 ° C) or more. 8. The method according to claim 7, wherein the settling mixture has a temperature after molding of about (T cloud ) or more. The method of claim 1, wherein the antisolvent has a temperature just before mixing with the concentrate (T cloud - 50 ° C) or higher. The method of claim 1, wherein the solvent comprises a C ₆ -C ₁₈ aromatic hydrocarbon. The method of claim 10, wherein the solvent is selected from the group consisting of toluene, xylene, and a mixture containing at least one of toluene and xylene. The method of claim 10, wherein the solvent further comprises a C ₃ -C ₈ aliphatic alcohol (aliphatic alcohol). 11. The method of claim 10, wherein the solvent further comprises methanol, ethanol, or a mixture comprising one or more of methanol and ethanol. The method of claim 1, wherein the antisolvent comprises an alcohol having from 1 to about 10 carbon atoms; Ketones having from about 3 to about 10 carbon atoms; Alkanes having from about 5 to about 10 carbon atoms; And a combination comprising at least one of the foregoing materials. 15. The method of claim 14, wherein the antisolvent comprises methanol. The method of claim 1, wherein the complex metal catalyst comprises one or more metal ions selected from group VIB, VIIB, VIII or IB on the periodic table. 17. The method of claim 16, wherein the complex metal catalyst comprises copper ions. 18. The method of claim 16, wherein the complex metal catalyst further comprises one or more nitrogen-containing ligands. 19. The method of claim 18, wherein the nitrogen-containing ligand comprises at least one of alkylenediamine ligand, primary monoamine, secondary monoamine, tertiary monoamine, aminoalcohol, oxine, and the nitrogen-containing ligand. Method for producing a poly (arylene ether), characterized in that selected from the group consisting of a combination containing. The method of claim 1, (i) the monohydric phenol comprises 2,6-dimethylphenol and 2,3,6-trimethylphenol; (ii) the solvent is selected from the group consisting of toluene, xylene and mixtures comprising at least one of toluene and xylene; (iii) the antisolvent comprises methanol; And (iv) wherein the settling mixture has a temperature of about 44 ° C. or higher after molding. 21. The method of claim 20, wherein said settling mixture has a temperature after molding of at least about < RTI ID = 0.0 > 48 C. < / RTI > 22. The method of claim 21, wherein said settling mixture has a temperature after molding of at least about < RTI ID = 0.0 > 51 C. < / RTI > 21. The method of claim 20, wherein the antisolvent further comprises one or more of toluene and water. The method of claim 20, wherein the antisolvent comprises about 70 wt% to about 100 wt% methanol; 0% to about 20% by weight of toluene; And 0 wt% to about 10 wt% of water. The method of claim 1, wherein the temperature of the settling mixture is adjusted to an extent sufficient to reduce particle levels of less than about 38 microns to less than about 18 weight percent in the precipitated poly (arylene ether). Method for producing a poly (arylene ether) characterized in that. As a method for producing a poly (arylene ether), (a) oxidatively coupling 2,6-dimethylphenol and 2,3,6-trimethylphenol in the presence of a complex metal catalyst and a solvent comprising at least one of toluene and xylene to form a poly (arylene ether ) Preparing a copolymer resin; (b) removing a portion of the solvent to prepare a concentrate having a cloud point T cloud ; And (c) mixing the concentrate with an antisolvent comprising at least about 50 weight percent methanol to settle the poly (arylene ether) copolymer in the form of a settling mixture; The concentrate has a temperature of at least about 70 ° C. immediately before mixing with the antisolvent; And The settling mixture is a method for producing a poly (arylene ether), characterized in that the temperature after molding is about 44 ℃ or more. The method of claim 26, The concentrate comprises about 25% to about 55% by weight of poly (arylene ether); The complex metal catalyst comprises a copper ion, a secondary alkylenediamine redand, a secondary monoamine and a tertiary monoamine; The complex metal catalyst is recovered in an aqueous solution after step (a); And Wherein the precipitated poly (arylene ether) copolymer has an intrinsic viscosity of about 0.25 dL / g to about 0.50 dL / g. As a method for producing a poly (arylene ether),  (I) poly (arylene ether) by oxidatively coupling 2,6-dimethylphenol and 2,3,6-trimethylphenol in the presence of a complex metal catalyst and a solvent comprising at least one of toluene and xylene ) Preparing a copolymer resin; (II) removing a portion of the solvent to prepare a concentrate having a cloud point T cloud ; And (III) mixing the concentrate with an antisolvent to settle the poly (arylene ether) copolymer in the form of a settling mixture; The concentrate is such that the temperature T just before mixing with the antisolvent satisfies the following inequality, T ( [Φ s-(0.296 x IV + 1.27 x TMP -35.7 ] / [ 1.97 (1-0.00795 x IV -0.0249 x TMP ] -10 ) , Where Φ s is the polymer concentration (expressed in weight percent), IV is the intrinsic viscosity of the copolymer (expressed in mL / g) in 25 ° C. chloroform, and TMP is 2,3,6-trimethylphenol in the copolymer. Content (expressed in weight percent); And The settling mixture is a method of producing a poly (arylene ether), characterized in that the temperature after molding is about (T cloud -40 ℃) or more. 2,6-dimethyl-1,4-phenylene ether units and 2,3,6-trimethyl-1,4-phenylene ether units, having an intrinsic viscosity of about 0.25 dL / g to about 0.50 dL / g , Wherein the particles of less than about 38 micrometers comprise less than about 18 weight percent of the poly (arylene ether) copolymer powder. 30. The poly (arylene ether) copolymer powder of claim 29 comprising less than about 15 weight percent of particles less than about 38 micrometers. 30. The method of claim 29, wherein the weight ratio of the 2,6-dimethyl-1,4-phenylene ether unit and the 2,3,6-trimethyl-1,4-phenylene ether unit is about 3: 1 to about 6: 1 ego; The copolymer is a poly (arylene ether) copolymer powder, characterized in that having a glass transition temperature (Tg) of about 220 ℃ or more. A poly (arylene ether) prepared by the method of claim 1, wherein the poly (arylene ether) comprises less than about 18% by weight of particles less than about 38 micrometers. 33. A thermoplastic composition comprising the poly (arylene ether) of claim 32. 34. The thermoplastic composition of claim 33, further comprising a polyamide resin.

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