JPH0410496B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing aromatic sulfide polymers having high melt viscosity. More specifically, a finely powdered aromatic sulfide polymer with a specific surface area of 20 m ² /g or more is suspended or wet,
The present invention relates to a method for producing an aromatic sulfide polymer having a high melt viscosity uniformly and with almost no coloring by treating it with an oxidizing agent or a radical generator at a temperature of 200°C. In recent years, thermoplastic resins with higher heat resistance have been increasingly required for electronic equipment parts, automobile equipment parts, chemical equipment parts, and the like. Aromatic sulfide polymers are one of the resins that are expected to meet these demands, but this polymer is linear and difficult to obtain with a sufficiently high degree of polymerization. If used as is, the melt viscosity is insufficient, making it difficult to process into films, sheets, threads, and other molded products. Therefore, aromatic sulfide polymers are usually processed by subjecting them to a treatment to increase their melt viscosity. The following methods are conventionally known as methods for increasing the melt viscosity of aromatic sulfide polymers. (1) A method of treating an aromatic sulfide polymer with a gas containing oxygen at a high temperature of 200 to 300℃ (2) A method of adding a crosslinking agent (such as trichlorobenzene) during polymerization to form a branched aromatic sulfide polymer, etc. It is. However, with method (1), the coloring of the processed material is significant, the heat treatment is difficult to perform uniformly, the threads tend to break even when spun, and it is difficult to spin fine threads. However, there were problems such as the fact that the transparency of the system was significantly lower. In addition, method (2) has many branched structures and poor linearity, resulting in unsatisfactory strength and toughness even when formed into threads, films, sheets, etc. The inventors have diligently searched for a method to produce aromatic sulfide polymers with high melt viscosity uniformly and with almost no coloring, and as a result, they have produced aromatic sulfide polymers in the form of fine powder with a specific surface area of 20 m ² /g or more. We have discovered that this objective can be achieved by treating it in a suspended state (slurry state) or in a wet state (wet cake state) at a temperature of 0 to 200°C using an oxidizing agent or a radical generator, and we have developed the present invention. invention has been achieved. According to the present invention, an aromatic sulfide polymer can be uniformly increased to a desired melt viscosity, and a resin can be obtained that can be molded into highly transparent films, sheets, etc. with extremely little coloration and virtually no stickiness. was completed. The aromatic sulfide polymer used in the present invention is not particularly limited as long as it can be obtained in the form of fine powder with a specific surface area of 20 m ² /g or more.
3354129, 3919177, 4089847, etc., which are synthesized by the reaction of a polyhaloaromatic compound such as dichlorobenzene with an alkali metal sulfide in a polar solvent. Can be used. Examples of aromatic sulfide polymers include polyphenylene sulfide synthesized from dichlorobenzene and sodium sulfide, and copolymers with other polyhaloaromatic compounds that can be copolymerized with dichlorobenzene and sodium sulfide. It doesn't matter. The aromatic sulfide polymer used is in the form of fine powder and has a specific surface area of at least 20 m ² /g in order to cause a uniform crosslinking reaction as described above. In particular, a specific surface area of 30 m ² /g or more is desirable. Items having such a shape include wet cakes that have not been subjected to a drying process during the post-treatment of producing aromatic sulfide polymers by the above-mentioned polymerization method, or dry powder obtained from the wet cakes that have not undergone a sintering process. Preferably, those that have not undergone In particular, a wet cake state polymer is most preferred since it has a small particle size and the largest specific surface area. Examples of the oxidizing agent or radical generating agent used as the treatment agent in the present invention include the following inorganic reagents and organic reagents. Inorganic reagents include hydrogen peroxide, alkali peroxide (sodium peroxide, etc.), hypochlorite (sodium hypochlorite, etc.), chlorate (sodium chlorate, etc.), perchlorate (perchlorate, etc.). sodium acid, etc.),
Salad powder, persulfate (ammonium persulfate, etc.), nitric acid,
Examples include permanganates (potassium permanganate, etc.) and dichromates (potassium dichromate, etc.). Examples of organic reagents include organic peroxydicarbonates (isopropyl peroxydicarbonate, etc.), organic peroxides (benzoyl peroxide, etc.), organic hydroperoxides (cumene hydroperoxide, etc.), ketone peroxide, and organic peresters (peroxide, etc.). Ethyl acetate, etc.), organic peracids (peracetic acid, etc.), azo compounds (azo, bis-isobutyronitrile, etc.), maleic anhydride, and nitro compounds (dinitronaphthalene, etc.) are effective. In particular, hydrogen peroxide, hypochlorite, etc. are excellent in that they uniformly increase the melt viscosity. The state of the polymer before treatment is preferably a wet cake that has not gone through the drying process after the polymerization reaction or a dry powder that has not gone through the sintering process, as described above, but this polymer and the treatment agent should be uniformly and thoroughly brought into contact with each other. Examples of methods include: (1) A method in which the wet cake or dry powder described above is redispersed in a solvent such as water, a treatment agent is added in a suspended state, and the mixture is heated. (2) The wet cake or dry powder described above is treated. There is a method in which a solution of the agent dissolved in a solvent is stirred to uniformly impregnate the material and then heated in a wet state. Method (1) is the best from the standpoint of achieving uniform processing. In the above-mentioned two methods, ordinary solvents can be used as the solvent for the suspension slurry medium such as wet cake or the processing agent, except for particularly strong reducing solvents. Water is a typical inorganic solvent. Examples of organic solvents include alcohols (methanol, etc.), ketones (acetone, etc.), ethers (dioxane, etc.), aliphatic hydrocarbons (petroleum ether, hexane, decalin, etc.), and aromatic hydrocarbons (toluene, etc.).
xylene, tetralin, etc.), halogenated hydrocarbons (EDC, etc.), esters (ethyl acetate, etc.), amines (pyridine, etc.), amides (dimethylformamide,
N-methylpyrrolidone, etc.), sulfoxide (dimethylsulfoxide), carboxylic acid (acetic acid, etc.), and the like. These can be used alone or in combination of two or more. In any case, it is important to select a solvent that can dissolve the processing agent. Water, in particular, is excellent from the standpoints of safety, non-pollution, and economy. The optimum amount of the oxidizing agent or radical generator used as a processing agent varies depending on the type of processing agent, the melt viscosity of the polymer to be treated, the melt viscosity of the target material to be treated, and other processing conditions, but usually aromatic sulfide The range is preferably from 10 ^-4 to 10 ^-1 mol, particularly preferably from 10 ^-3 to 5 x 10 ^-2 mol per mole of basic unit of polymer (ie 108 g in the case of polyphenylene sulfide). If the amount is less than 10 ^-4 mol, it is too small and the effect of increasing melt viscosity is poor. A mole of 10 ^-1 mole or more is too excessive and undesirable from an economic standpoint. The treatment temperature is mainly determined by the type of treatment agent used, but a range of 0 to 200°C is used for uniform melt viscosity increasing treatment. If the temperature is below 0°C, the treatment reaction time becomes long, which is not preferable from an economical point of view. A temperature of 200° C. or higher is not preferable because the treatment reaction may become radical and the treatment may become non-uniform. In particular, a temperature range of room temperature to 160°C is preferred because excellent physical properties can be obtained quickly. Although the details of the mechanism of the melt viscosity increasing treatment of the present invention have not yet been elucidated, it is assumed that in addition to the molecular chain elongation reaction, some branching reactions, crosslinking reactions, etc. also occur. Furthermore, although the details of the structure of the polymer have not been elucidated, it is assumed that extreme reactions such as aromatic ring condensation reactions are unlikely to occur, considering that there is very little coloration. Aromatic sulfide polymers whose melt viscosity has been increased by the method of the present invention have excellent thread-like properties, are transparent, have very little coloration, and are tough, heat-resistant films, sheets, etc.
It can be extremely easily molded into fibers, etc. Furthermore, the aromatic sulfide polymer with increased melt viscosity of the present invention is filled with a heat stabilizer, a lubricant, a crystal nucleating agent, an ultraviolet absorber, a coloring agent, and a powder such as carbon black, calcium carbonate powder, silica powder, titanium oxide powder, etc. It is also possible to add fibrous fillers such as carbon fibers, glass fibers, asbestos, polyaramid fibers, etc. Also polycarbonate, polyphenylene oxide, polysulfone, polyarylene, polyacetal, polyimide, polyamide,
It is also possible to use a mixture of one or more synthetic resins such as polyester, polystyrene, and ABS. Examples are shown below, but the present invention is not limited thereto. Examples 1 to 8 (i) Preparation of aromatic sulfide polymer Na ₂ S・5H ₂ O 3.612 Kg (21.5 mol),
20.0 kg of Na ₂ SO ₄ and about 10 kg of water were charged into a large rotary evaporator and heated at a bath temperature of 150 to 160° C. After dissolution, the pressure was reduced to distill off about 10.5 kg of water. Next, pour out all the contents from the evaporator into a Teflon vat, and heat it in a vacuum dryer at about 200°C.
Drying at 8 Torr for 20 hours yielded a substantially anhydrous amorphous glassy solid. It was ground into fine particles in a mortar. 25 Charge 16 of N-methylpyrrolidone (NMR) to which the entire amount of the amorphous glassy solid mentioned above and 150 g of water was added to an autoclave equipped with a stirrer, and further add 2.94 g of p-dichlorobenzene.
Kg (20.0 mol) was charged. After purging the autoclave with _N2 , it was heated at 214°C for 21 hours to carry out a polymerization reaction. After the reaction was completed, 3 moles of ammonium sulfate were added to the reaction mixture, and the mixture was charged into a large rotary evaporator, and NMP was distilled and recovered under reduced pressure while heating at a bath temperature of 80 to 90°C. After removing NMP,
The solid matter left in the can was washed alternately with acetone and hot water three times, and then dehydrated using a dehydrator to obtain an aromatic sulfide polymer wet cake A (w). A part of A(w) was dried under reduced pressure at 40° C., and the specific surface area was measured to be 155 m ² /g. The specific surface area was measured by the BET method (using Akiyusorb 2100-01 manufactured by Shimadzu Corporation). A portion of A(w) was dried at 80°C overnight to obtain dry powder A(d). The specific surface area of A(d) was 123 m ² /g. (ii) Melt viscosity increasing treatment by suspension method The above-mentioned polymer A(w) or its dry powder A(d)
Weighed 32.4 g each (in terms of dry powder), charged it to a high-speed mixer, and stirred it at high speed for 3 minutes with 300 ml of various solvents to prepare a uniformly dispersed suspension. Charge each of them into a 0.5 reactor equipped with a stirrer, and when the temperature reaches a predetermined temperature, a solution of various processing agents dissolved in 15 ml of the same type of solvent is added, and the treatment is carried out by heating at that temperature for a predetermined period of time. Ta. After the treatment, they were washed alternately with acetone and hot water three times each, and dried at 80°C to obtain dry powders of each treated product. The physical properties of the obtained dry powder were evaluated by the method described below. The results are summarized in Table 1. (iii) Evaluation of physical properties Each of the dry powders obtained by the above method was pressed in a press at 310° C. without preheating, and then rapidly cooled and formed into a sheet with a thickness of 0.2 mm. A part of the press sheet was cut into pieces and tested at a load of 50 kg/cm ² and 310°C using a Koka type flow tester (manufactured by Shimadzu Corporation).
The melt viscosity η ^* was measured. In addition, a part of the shredded sheet was extruded from a 0.5 mmφ4 hole nozzle using a melt tension tester (manufactured by Toyo Seiki Co., Ltd.).
The yarn was wound and spun at a speed such that the diameter of the yarn became approximately 12 μm, and the spinning suitability (stringinability) was evaluated. Also, part of the press sheet is film stretcher (simultaneous biaxial stretching machine manufactured by TM Long Co., Ltd.)
The film was stretched 3.3 times both lengthwise and widthwise at approximately 97°C using a film to form a biaxially stretched film. The obtained stretched film was evaluated for coloring state, transparency, presence or absence of fish eyes, and tensile strength. The number of fisheyes found in a biaxially stretched film measuring 10 cm x 10 cm was evaluated. Example 9 (Melt viscosity increasing treatment by wetting method) Weighed 324 g (in terms of dry powder) of the wet cake A (w) described above, sprinkled it with 15 ml of an aqueous solution containing 0.03 mol of hydrogen peroxide, and kneaded it with a small kneader. Treatment was performed by heating at 50°C for 7 hours. The treated product was washed alternately with acetone and hot water three times each, and then dried at 80°C to obtain a dry powder of the treated product. The obtained dry powder was evaluated in the same manner as in Examples 1-8. The results obtained are shown in Table 1. Comparative Examples 1-2 The dry powder A(d) was subjected to the same physical property evaluation as in the example without being heat-treated (Comparative Example 1). A(d) was also heat treated in air at 260°C for 3 hours to evaluate its physical properties (Comparative Example 2). The results obtained are shown in Table 1. Comparative Example 3 Dry powder A(d) was sintered by heating in air at 260°C for 2 hours. The melt viscosity of this substance is
When the specific surface area was measured at 3000 poise, it was found to be 18 m ² /g. Example 1: Take 32.4g of this polymer B(d)
After recovering the polymer by hydrogen peroxide treatment under exactly the same conditions as above, physical properties were evaluated. The results are shown in Table 1.

【table】

[Table] *1 Number of moles of treatment agent/number of moles of basic polymer unit *2 Stretching ratio 2.1×2.1
As is clear from Comparative Example 1 in Table 1, untreated material A
(d) had a low melt viscosity, making it difficult to spin, and even for biaxially stretched films, it was not possible to obtain a sufficiently high stretching ratio. Furthermore, compared to Comparative Example 2, the examples of the present invention had excellent spinnability, and the films had little coloration and good transparency, were substantially free of fish eyes, and had high strength. Comparative Example 3 shows that polymer B(d), whose specific surface area has been reduced by sintering at a high temperature, has a small effect even if the viscosity is increased by the method of the present invention.

Claims (1)

[Claims] 1. A finely powdered aromatic sulfide polymer having a specific surface area of 20 m ² /g or more in a suspended or wet state.
A method for producing an aromatic sulfide polymer having a high melt viscosity, which comprises treating with an oxidizing agent or a radical generator at a temperature of 220°C. 2. One or two oxidizing agents or radical generators selected from hydrogen peroxide, hypochlorites, persulfates, mustard powder, permanganates, organic peroxides, organic peroxydicarbonates, and azo compounds. A method for producing an aromatic sulfide polymer according to claim 1, in which more than one type of aromatic sulfide polymer is used. 3. The aromatic sulfide according to claim 1 or 2, wherein the suspended or wet state is achieved by using water, a non-reducing organic solvent, or a mixture thereof as a suspending medium or wetting agent. Method for producing polymers. 4. The aromatic sulfide polymer according to any one of claims 1 to 3, which uses a wet cake that has not undergone a drying process or a dry powder that has not undergone a sintering process as the finely powdered aromatic sulfide polymer. Method of manufacturing coalescence.