JPH0545617B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention is directed to
This invention relates to a polyphenylene sulfone microporous molded product. [Prior art] Microporous molded products such as microporous films and microporous membranes have traditionally been used in seawater desalination, pure water production for the electronics industry, sewage treatment in the paper industry and pulp mills, and electrolytic coating solutions. It can be used for pollution-related purposes such as industrial water recovery and waste liquid treatment such as oil and water emulsion separation, and medical-related filtration materials such as artificial kidneys for plasma separation, as well as for various batteries. It is being used in many different fields such as separators. In recent years, as membrane separation processing using such microporous molded products has spread,
Demand for microporous molded products having excellent mechanical strength is increasing in this field as well. In response to these demands, fluororesins containing fluorine atoms, such as polytetrafluoroethylene and polyvinylidene fluoride, have extremely excellent chemical resistance, heat resistance, weather resistance, etc. Microporous molded products have been proposed. However, microporous molded products made of such resins have high heat resistance or low mechanical strength.
Although it has extremely excellent properties, it has the disadvantage that its range of application is severely limited depending on the application. Therefore, in order to obtain a microporous molded product having sufficient mechanical strength and excellent heat resistance and chemical resistance, aromatic polysulfones represented by the following formulas (), (), (), Various separation membranes using polymers consisting of structural units having ether bonds in their main chains have been proposed (Japanese Patent Application Laid-open Nos. 14376-1982, 30803-1980, etc.). However, having an ether bond in such a main chain,
Since so-called polyether sulfone generally does not have a melting point, it has been dissolved in an amide-based organic solvent or the like and formed into a separation membrane or the like by a wet method. For this reason,
Naturally, it has the disadvantage that it dissolves in such amide-based organic solvents and cannot be applied in such organic solvents. Polyparaphenylene sulfone is also used as polysulfone.

[Problem that the invention seeks to solve]

The purpose of the present invention is to have sufficient mechanical strength without impairing the extremely excellent heat resistance inherent to such a polyphenylene sulfone polymer, and to have extremely excellent chemical resistance against concentrated sulfuric acid and concentrated nitric acid. The object of the present invention is to provide a novel microporous polyphenylene sulfone molded product having properties. [Means for Solving the Problems] The present inventors have arrived at the present invention as a result of intensive studies to achieve the object of the present invention, and the results have shown that not only heat resistance but also chemical resistance has been achieved. The present inventors have discovered that a microporous molded product with significantly improved properties can be obtained, leading to the present invention. That is, the present invention has the following configuration. (1) General formula ()

It mainly consists of a structural unit represented by the formula (where X=0, 1, or 2) and occupies the structural unit.

Formed from a resin with a structural unit ratio of [Formula] of 0.3 or more, and a porosity of 10 to 10.
A polyphenylene sulfone microporous molded article having 90% substantially continuous micropores and a specific surface area of 0.4 m ² /g or more. (2)

[Formula] The polyphenylene sulfone microporous molded product according to claim 1, wherein the structural unit ratio is 0.5 or more. The present invention will be explained in detail below. Polyphenylene sulfone (hereinafter referred to as PPSO) of the present invention
A microporous molded product has the general formula ()

[Formula] (where X = 0, 1, or 2) consists mainly of the structural unit and occupies the structural unit

Refers to a microporous molded product mainly formed from PPSO chains with a structural unit ratio of 0.3 or more. It takes

If the structural unit ratio of [Formula] (hereinafter abbreviated as PPSO ratio) is less than 0.3,
Exceptionally excellent heat resistance cannot be obtained. The PPSO conversion rate is preferably at least 0.3, preferably 0.5 or more, more preferably 0.7 or more, particularly preferably 0.8 or more. Also, in the structural unit here,

[Formula] A/

[Formula] The B ratio is preferably 1.0 or more, more preferably 2.0 or more. It is particularly preferable if it is 3 or more. In particular, almost fully polysulfonated products with a PPSO conversion ratio of 0.9 or more and A/B≧3 have super heat resistance, so
Particularly preferred. Here, the main chains having such a structure may be partially bonded to each other by oxygen atoms or the like to form a so-called three-dimensional structure. In addition, the bond between the benzene ring and the sulfur atom in the structural unit formula shown in general formula () may be either a para bond or a meta bond, but a para bond is preferable because it provides high crystallinity. preferable. Moreover, a hydroxyl group, an oxygen atom, etc. may be partially added to the benzene ring in the general formula (). Moreover, the main component as used in the present invention means containing at least 90 mol% or more of the general formula (). If the main component is less than 90 mol%, the crystallinity of the obtained polymer may decrease,
It is difficult to obtain the microporous molded product of the present invention having excellent heat resistance and chemical resistance such as a lower transition temperature. Now, the PPSO microporous molded product of the present invention has substantially continuous micropores with a porosity of 10 to 90%,
It consists of a microporous molded product with a specific surface area of 0.4 m ² /g or more. The pore diameter of such microporous material varies depending on the purpose of use of such microporous molded product, but for example,
In the range of 0.001 to 0.05μ ultrafiltration membranes, filtration membranes for sewage treatment in paper mills and pulp mills are used.
Alternatively, it can be used as an oil-resistant membrane used in the production of edible oils such as soybean oil, or as a precision filtration membrane of 0.01 to 5μ for plasma separation or as a separator for various batteries.
Furthermore, it can be used as a purification filter for concentrated sulfuric acid, concentrated nitric acid, etc. In addition, a material having a rather large pore diameter of 5 μm or more can be used as a heat-resistant heat insulating material, and such pore diameter can be arbitrarily selected depending on the purpose of use and is not particularly limited. In addition, "substantially continuous micropores" does not necessarily mean that all the micropores are continuous, and the molded product has at least 1×10 ⁴ cc/
This means that it has air permeability of cm ² /sec. On the other hand, the porosity is in the range of 10 to 90%. If the porosity is less than 10%, the filtration area will be small and the pressure loss will be too large. On the other hand, if it exceeds 90%, the mechanical strength will be low and the applications will be limited. Also, the specific surface area is 0.4m ² /
g or more is required, more preferably 1.5m ² /g
The above is desirable. When the specific surface area is less than 0.4 m ² /g,
The filtration area is small, and clogging occurs quickly, making it difficult to withstand long-term use. Here, the specific surface area means the surface area of the microporous molded material per gram of microporous molded material, and is referred to as the so-called BET (Brunauer-Emmet-
It can be measured using the Teller method. Further, the porosity can be determined from the apparent density and true density of the microporous molded product as follows: porosity = (1-apparent density/true density) x 100 (%). The microporous molded product referred to in the present invention includes forms such as a film-like flat membrane, a tube-like tubular body, a nonwoven fabric thermocompressed body, a sponge shape, and a granular shape, and the shape of such a microporous molded product is It can be arbitrarily selected depending on the purpose of use, and is not limited to these. Next, a specific method for producing an example of the PPSO microporous molded product of the present invention will be described below. For example, the PPSO microporous molded product of the present invention can be obtained by oxidizing a microporous molded product made of polyphenylene sulfide using an organic peracid. First, as a method for producing polyphenylene sulfide, for example, as a particularly preferred application example of such polyphenylene sulfide, PPS
The method for producing it is to react an alkali sulfide and a paradihalogenated benzene in a polar organic solvent at high temperature and pressure. In particular, it is preferable to react sodium sulfide and paradichlorobenzene in an amide-based high-boiling polar solvent such as N-methyl-pyrrolidone. Next, using such polyphenylene sulfide, a microporous molded product having substantially continuous micropores with a porosity of 10 to 90% and a specific surface area of 0.4 m ² /g or more is formed. . As for the manufacturing method of such a microporous molded product, wet (or dry-wet) coagulation method, other component elution method, film stretching method, solvent evaporation method, nonwoven fabric thermocompression bonding method, etc. can be applied, but the method is limited to these methods. It's not a thing. Thereafter, the polyphenylene sulfide microporous molded product obtained in this way is treated with an organic peracid as described below to form a structural unit of the molded product.

[Formula], at least 30 mol% or more

〔Example〕

Example 1 300 manufactured by Toray Phillips Petroleum Co., Ltd.
Apparent viscosity at ℃ 4000 poise, Tg 90℃,
50 parts by weight of PPS fine powder having a Tm of 280°C and 50 parts by weight of trimellitic acid copolymerized polyethylene terephthalate fine powder were supplied to the Extreader.
Mixed and melted at ℃, extruded from a T-die with a linear lip of length 200 mm and gap of 1.0 mm, width 150 mm, thickness
A 400μ unstretched sheet was obtained. Stretch the sheet vertically and horizontally at 95℃ using a film stretcher.
Simultaneous biaxial stretching to 3.0 times, followed by constant tension heat treatment at 220°C for 1 minute using a hot air oven, resulting in a thickness of 40μ.
A film sample was obtained. Next, the trimellitic acid copolymerized polyethylene terephthalate was decomposed and removed using 30% sodium hydroxide to obtain a microporous film having a porosity of 50% and a specific surface area of 22 m ² /g. Thereafter, the microporous film was treated in a commercially available peracetic acid solution (9% concentration product in acetic acid) at room temperature (30°C) for 3 hours, followed by washing, neutralization, and washing with water, and then drying. The obtained microporous film was subjected to NMR and ESCA.
(Electron Spectroscopy for Chemical
Analysis), the structural unit of the polymer forming the microporous film was

[Formula] A is 78 mol%,

[Formula] B is 12 mol%,

[Formula] was 10 moles. That is, a microporous film with a PPSO conversion ratio of 0.78 was obtained. In addition, the porosity of this film is 50%, the specific surface area is 17 m ² /g, and the air permeability is 1 × 10 ⁴ cc/cm ² /sec.
It was a continuous microporous film as described above. Such a microporous film can be prepared using concentrated nitric acid, concentrated sulfuric acid,
No morphological change occurred when exposed to strong acids such as concentrated hydrochloric acid, 30% ammonia aqueous solution, and various organic solvents including amide-based organic solvents. Even after hanging for 24 hours, no creep failure was observed, and a significant improvement in heat resistance was confirmed. Example 2 300 manufactured by Toray-Philips Petroleum Co., Ltd.
20 parts by weight of PPS resin having an apparent viscosity of 4500 poise at 245°C, 53 parts by weight of N-methyl-2-pyrrolidone, and 27 parts by weight of diethylene glycol were melted under pressure at 245°C to prepare a molded film. Using a 0.5 mm slit-shaped nozzle, pour the solution into
Water was allowed to flow out from both sides of the mouthpiece slit, extruded into water, and solidified to obtain a microporous membrane with a porosity of 25% and a specific surface area of 5 m ² /g. This microporous membrane was then treated in a 9% peracetic acid solution at room temperature for 1 hour, followed by washing with water, neutralization, washing with water, and drying. When the obtained microporous membrane was analyzed by ESCA, the PPSO conversion rate was 0.78. In addition, the porosity of this microporous membrane is 25%, and the specific surface area is 4.
m ² /g, and the membrane had a continuous microporous membrane with air permeability of 1×10 ⁴ cc/cm ² /sec or more. When this microporous membrane was left in high-temperature air at 300°C for one day, almost no coloration was observed, and the strength retention rate after high-temperature treatment was extremely high at 85%. Example 3 Using the same PPS fine powder as in Example 1, the die temperature was
Melt extruded from a slit die at 310°C, with a width of 150 mm.
An unstretched film with a thickness of 200 μm and a thickness of 200 μm was obtained. The film was subjected to tension heat treatment for 2 minutes at 240°C using a hot air oven, and then simultaneously stretched 1.8 times both vertically and horizontally at 265°C using a film stretcher.
A microporous film with a porosity of 30% and a specific surface area of 15 m ² /g was obtained by axial stretching. The microporous film was treated with 9% peracetic acid for 1 hour, then washed with water, neutralized, washed with water, and dried. The obtained microporous film has a PPSO conversion ratio of 0.85, a porosity of 30%, and a specific surface area of 12 m ² /g.
It was a continuous microporous film with air permeability of 1×10 ⁴ cc/cm ² /sec or more. It did not decompose even in 69% high concentration nitric acid (1.42), and the strength retention rate was 90% after treatment at 300℃ for 24 hours, significantly improving chemical resistance and heat resistance. Comparative Example 1 In place of the 9% peracetic acid treatment in Example 3, 10% sodium hypochlorite was used and treatment was performed at 90°C for 1 hour. When the obtained porous material was analyzed by ESCA, it was found that it mainly had a PPS structure, and the PPSO conversion rate was 0.12.
When I tried to perform the same treatment as in Example 3, I found that it had become extremely brittle, and the treatment turned it into tatters. In other words, it was found that microporous molded products with a low PPSO conversion rate have low chemical resistance and heat resistance. Comparative Example 2 The PPS microporous film of Example 2 before being converted into PPSO was
Three-dimensional crosslinking was performed by heat treatment at 200°C for 4 hours and air oxidation. Most of the structural units were composed of PPS structure, and no PPSO structural unit was observed. Comparative Example 2 is the same as Example 2.
When treated at 300℃ for 24 hours, the film melted and
It no longer retained its film form.
In other words, it was found that even if the main chain is partially crosslinked, if it is not converted into PPSO, the chemical resistance and heat resistance are low. [Effects of the Invention] The polyphenylene sulfone microporous molded product of the present invention does not deteriorate even when exposed to highly concentrated concentrated sulfuric acid or concentrated nitric acid, and is extremely excellent in heat resistance and chemical resistance. For this reason, concentrated sulfuric acid, the demand for which has been increasing in recent years,
Excellent heat resistance, such as purification filters for concentrated nitric acid, various filters in desulfurization and denitrification smoke gas equipment, battery separators, and recovery of electrolytic coating solutions.
It can be preferably applied to filters, separation membranes, etc. in fields where chemical resistance is required.

Claims (1)

[Claims] 1 Mainly composed of structural units represented by the general formula () [Formula] (where X = 0, 1, or 2), and the proportion of the structural units of [Formula] in the structural units; is formed from a resin with a porosity of 0.3 or more, has substantially continuous micropores with a porosity of 10 to 90%, and has a specific surface area of 0.4.
1. A microporous molded polyphenylene sulfone having a polyphenylene sulfone density of m ² /g or more. 2. The polyphenylene sulfone microporous molded product according to claim 1, wherein the structural unit ratio of the formula is 0.5 or more.