JPH078543B2 - Method for hydrophilizing a molded aromatic polysulfone - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for hydrophilizing an aromatic polysulfone molded product, and more specifically, an aromatic compound containing a polymer having a hydrophobic portion and a hydrophilic portion. By subjecting the polysulfone molded product as it is, preferably in a state where the hydrophilic substance is in contact with the surface of the molded product, to heat treatment at a temperature lower than the glass transition temperature of the aromatic polysulfone, various parts, films, various plastic products, separation The present invention relates to a treatment method for improving the hydrophilicity of the surface of a molded product molded as a film or the like.

(Prior Art) Aromatic polysulfones are widely used as engineering resins having excellent chemical and thermal durability. Many aromatic polyaryl ether sulfone polymers are known as aromatic polysulfones, and these resins are generally represented by the formula: Is characterized by a structure containing a repeating unit represented by As expected from this structure, aromatic folysulfone has excellent durability and stability, but shows hydrophobic property. As a typical aromatic polysulfone, it is marketed under the trade name of Victrex from Imperial Chemical Industries, Ltd. and Udel from Union Carbide Co., respectively, but the water absorption rate is 0.4% for the former and 0.3% for the latter (both are AS
TM D570), which has a water absorption rate of 1/10 or less of that of cellulose acetate, which is known as a hydrophilic resin. Due to this hydrophobic property, the aromatic polysulfone had many problems such as "the surface is not easily splashed with water and easily dried", "easy to get dirty", "easy to be charged", and "hard to adhere". .

As a method of effectively solving such a problem, the present inventors have made the aromatic polysulfone resin hydrophilic by effectively incorporating a polymer having a hydrophobic portion and a hydrophilic portion into the aromatic polysulfone resin. I proposed the method of giving. For example, Japanese Patent Application No. 61-041992 proposes a method of using a block polymer of an aromatic polysulfone polymer and a hydrophilic compound as a polymer having a hydrophobic portion and a hydrophilic portion.

A molded product molded from the aromatic polysulfone obtained from the above method shows good hydrophilicity without impairing the excellent physical properties of the aromatic polysulfone itself, and prevents the surface of the molded product from being electrified or contaminated. Could be done. Further, by appropriately selecting the type and content of the polymer having a hydrophobic part and a hydrophilic part to be added to the aromatic polysulfone, it was possible to control the physical properties of the target molded article and the hydrophilicity of the surface.

However, there have been problems that the hydrophilicity of the surface of the obtained molded product is affected by the molding processing method and conditions, and the processing conditions may be limited by the peculiarities of the processing method.

With low molecular weight additives such as antistatic agents added to various plastic products, the additives migrate to the surface of the molded product even after molding at the glass transition temperature of the polymer that mainly constitutes the molded product, and the effect is expressed. It is known. But,
The glass transition temperature of aromatic polysulfones is generally 200 ° C.
The temperature is extremely high at the front and back, and at such temperatures, there were problems such as deformation, coloring, and performance deterioration of the molded product.

(Object of the Invention) As a result of further detailed study of the above method, the present inventors have found that an aromatic polysulfone molded article containing a polymer having a hydrophobic portion and a hydrophilic portion has a temperature lower than the glass transition temperature of the aromatic polysulfone. It was found that the surface can be hydrophilized without deteriorating the molded product by heat treatment with, and that the hydrophilic treatment can be more effectively carried out when the heat treatment is performed in the state where the hydrophilic substance and the molded product surface are in contact with each other. The present invention has been completed and the present invention has been completed.

The object of the present invention is to form an aromatic polysulfone molded article containing a polymer having a hydrophobic portion and a hydrophilic portion, without impairing the characteristics of the molded article such as the shape and performance given by various molding methods. It is to further improve the hydrophilicity of the surface of the molded product.

(Structure of the Invention) The present invention relates to "the aromatic polysulfone molded article is composed of an aromatic polysulfone containing a polymer having a hydrophobic portion and a hydrophilic portion, and the hydrophilic treatment is performed at a temperature lower than the glass transition temperature of the aromatic polysulfone. A method for hydrophilizing the surface of an aromatic polysulfone molded product, which is characterized in that it is a heat treatment to be carried out. "

Here, the aromatic polysulfone is a polymer having a repeating unit represented by the following general formula (1) or (2).

M-Rm-Mn-OlM-SO ₂ -MO- (1) -M-SO ₂ -M-SO ₂ -MO- (2) (wherein M is the same or different aromatic group, R Represents a divalent organic group, and m, n, and l each represent 0 or 1.) As a specific example, one of the following repeating units: Or Aromatic polysulfone having is preferably used as a molding material.

In addition, a polymer having a hydrophobic part composed of a substance insoluble in water and a hydrophilic part composed of a substance soluble in water means that a polymer having an alkyl, allyl or aromatic ring in its main chain or / and side chain as a hydrophobic part. It consists of an insoluble substance, and the main chain or side chain of the hydrophilic part is alcohol, carboxylic acid, sulfonic acid, ether,
Or consisting of a water-soluble substance containing a pyrrolidone ring,
It is a water-insoluble polymer in which the hydrophobic and hydrophilic parts are covalently bonded. This polymer can be synthesized from a monomer that constitutes the hydrophobic part and a monomer that constitutes the hydrophilic part by known means such as block polymerization, graft polymerization, or copolymerization, or a polymer having a reactive group. It is also possible to synthesize a block- or graft-type polymer from a polymer or oligomer consisting only of a hydrophobic part and a polymer or oligomer consisting only of a hydrophilic part by a polymer reaction using. Further, in view of compatibility between a polymer having a hydrophobic portion and a hydrophilic portion and aromatic polysulfone, and heat resistance of a molded product, it is desirable to use an aromatic polysulfone polymer or oligomer as the hydrophobic portion. And polymers described in Japanese Patent Application No. 61-7961. However, if the hydrophobic part is composed of a water-insoluble substance, the hydrophilic part is composed of a water-soluble substance, and is a water-insoluble polymer, other than the above-exemplified polymer containing the main chain and / or side chain It does not prevent the use of other polymers.

The molded product used in the present invention is a resin in which an aromatic polysulfone and a polymer having a hydrophobic portion and a hydrophilic portion are mixed at an arbitrary ratio, preferably aromatic polysulfone in an amount of 50 wt% or more. Various parts obtained by various processing methods such as the processing method that accompanies, the solvent dissolution such as film formation by the cast method, the wet film forming method,
Films, various plastic products, separation membranes, etc.

In the aromatic polysulfone containing a polymer having a hydrophobic portion and a hydrophilic portion, when a uniform melt or solution is solidified,
It is expected that the hydrophilic part will be microscopically separated from the hydrophobic part of the aromatic polysulfone polymer. However, depending on the molding method, such separation may be insufficiently solidified, that is, a molded product may be obtained. This is particularly remarkable on the surface of the molded product. Therefore, the heat treatment temperature of the present invention is
By keeping the temperature below the glass transition temperature of the aromatic polysulfone that constitutes the molded product and at room temperature or higher, deterioration of the molded product is prevented, and by promoting molecular movement on the surface, among the polymers having a hydrophobic part and a hydrophilic part, It is considered that the hydrophilic part covers the surface of the molded product more effectively.

Further, preferably, the heat treatment is performed in the state where the hydrophilic substance is in contact with the surface of the molded product. Therefore, in the surface layer of the molded product, the hydrophilic part of the polymer having a hydrophobic part and a hydrophilic part contained in the molded product shows a strong affinity with the hydrophilic substance, and the hydrophilic part has a hydrophilic part. It is expected that only the surface layer is plasticized, and it is considered that the surface is hydrophilized more effectively.

The heat treatment of the present invention is achieved by leaving the molded product in an atmosphere below the glass transition temperature of the aromatic polysulfone for a predetermined time, and the molded product is heat treated in a state in which the surface of the molded product is in contact with a hydrophilic substance. Is desirable.

The hydrophilic substance of the present invention is a substance that does not dissolve the molded product and is soluble in water, such as water, an aqueous solution of various salts such as salt, alcohols such as methanol and ethanol,
Glycols such as ethylene glycol and glycerin,
Ethers such as polyethylene glycol are preferably used. Water is most suitable industrially, but depending on the purpose, an aqueous solution of the above substances, steam or a mixture of steam may be used.

Ordinarily heat treatment, as it is or preferably, the molded product is immersed in a hydrophilic substance or placed under an atmosphere, and is lower than the glass transition temperature of the aromatic polysulfone, preferably 60 ° C to 170 ° C,
It is achieved by leaving it at the temperature for necessary time, preferably 10 seconds to 6 hours. After the heat treatment, washing and drying can be performed as needed.

(Effects of the Invention) The molded article treated according to the present invention has a property of the molded article such as shape and performance imparted by various molding methods without being deteriorated, as compared with the untreated molded article surface, It exhibits a large surface hydrophilicity.

Therefore, the hydrophilic treatment method of the present invention is applied to various parts in the electric and electronic fields, films for liquid crystal displays, housings, automobile parts, interior materials for aircraft, gears, dental materials, medical materials, steam sterilization containers. For use in a wide range of fields, such as aromatic polysulfone molded products containing polymers with hydrophobic and hydrophilic parts made by the most suitable processing method, cause deformation and deterioration such as distortion, bending, cracking, wrinkling In other words, the hydrophilicity of the surface thereof can be improved, and it can be provided as an excellent antistatic property, adhesive property, plating property, coating property, stain resistance, antithrombotic property and the like. In addition, the present invention is particularly prepared once for a separation membrane itself such as a reverse osmosis membrane, an ultrapermeability membrane, a membrane filter, etc., which has many restrictions on the preparation method, or when the molded product is used as a constituent element of the separation membrane. It is a very excellent method as a means for improving the hydrophilicity of the membrane surface while maintaining the original performance without destroying the fine structure of the separation membrane.

(Examples) Examples of the present invention will be described below.

Reference Example 1 Dimethyl sulfoxide (hereinafter referred to as DM
700 ml is put, and polyvinyl alcohol (made by Wako Pure Chemical Industries, degree of polymerization of about 500) is added as a hydrophilic part in a nitrogen stream.
Was added and dissolved by heating to 70 ° C. with stirring. Then, 3 ml of 1N aqueous potassium hydroxide solution was added as a base, and stirring was continued for 1 hour. Then, 32 g of aromatic polysulfone (Victrex 4800P, manufactured by Imperial Chemical Industries) was added as a hydrophobic portion, and the reaction solution was kept at 80 ° C. and stirred for 4 hours. The reaction solution was cooled to room temperature and then transferred to a 2 l separating funnel. The reaction solution was dropped into distilled water while vigorously stirring to obtain a white flake-like precipitate. The precipitate collected by suctioning was subjected to Soxhlet extraction treatment using water as an extract for 2 hours, then placed in a vacuum dryer and vacuum dried at 80 ° C. for one day. 28.1 g of white powder was obtained, and the recovery rate of the charged aromatic polysulfone was 88%.

The obtained polymer having a hydrophobic portion and a hydrophilic portion was soluble in a polar organic solvent such as DMSO, dimethylformamide, N-methyl-2-pyrrolidone.

In the 270 MHz FT-NMR spectrum analysis, 7.6% was a polyvinyl alcohol component.

Reference Examples 2, 3 and 4 Instead of the base, the hydrophobic portion and the hydrophilic portion in Reference Example 1, Table I
The same reaction was carried out using the base, the hydrophobic part and the hydrophilic part shown in to obtain a polymer. The results are shown in Table I.

Reference Examples 5, 6, 7 According to the graft polymer synthesis method shown in Example 1 of Japanese Patent Application No. 61-7961, a polymer having a hydrophobic portion and a hydrophilic portion is selected from the polymers constituting the hydrophobic portion and the hydrophilic portion shown in Table II. Obtained.

Examples 1 to 8 Films were prepared from the solutions of the polymers of Reference Examples 1 to 7 dissolved in DMSO at a concentration of 15 wt% by a casting method. These films were heat-treated while immersed in water and then dried again. The contact angle of water on the film surface before and after the treatment was measured using a goniometer-type contact angle measuring instrument (GI type manufactured by Elma Optical Co., Ltd.). The results are shown in Table III together with the heat treatment conditions.

Comparative Examples 1 and 2 The same procedure as in Examples 1 and 6 was repeated except that Victrex 4800P and 5003P were used instead of the polymers used in Reference Examples 1 and 5, respectively. The results are shown in Table III.

Examples 9, 10, 11, 12 Example 1 was repeated except that the polymer used, the treatment method and the heat treatment method were changed as shown in Table IV. The results are shown in Table IV.

Examples 13, 14, 15, 16 The polymers of Reference Examples 1 and 2 were each dissolved in DMSO at a concentration of 20% by weight and then degassed by standing to obtain a polymer solution for film formation. The polymer solution was cast from each polymer solution onto a polyester non-woven fabric (MF-80K, manufactured by Japan Vilene) with a doctor blade at a thickness of 150 μm and kept horizontal for 30 seconds. Then, the nonwoven fabric was immersed in a water bath at 10 ° C. and gelled to obtain a separation membrane.

Keep these separation membranes immersed in water at 90 ° C for 30 minutes or
Heat treatment was performed at 130 ° C for 15 minutes.

The performance evaluation after treatment is distilled water and ovalbumin (MW45
000, manufactured by Wako Pure Chemical Industries, Ltd.) 100ppm 1 / 15M phosphate buffer solution was used as a test solution, and a pressure over test of 3kg / cm ² was performed. Pure water hydraulic conductivity (Lp) and ovalbumin exclusion rate (Ro), respectively.
Was measured. Lp and Ro are defined by the following formula.

Furthermore, each film is made of Cytochrome-C (manufactured by Sigma).
It was immersed in a 2000 ppm phosphate buffer at room temperature for 5 hours, washed thoroughly with water, and then air dried. The amount of cytochrome-C adsorbed on the surface of these films was visually evaluated.

The respective results are shown in Table V. Further, no deformation due to heat treatment was observed in each film.

Comparative Examples 3 and 4 In Examples 13 and 15, the films which were not subjected to the heat treatment were evaluated in the same manner. The results are shown in Table V.

Comparative Examples 5, 6 and 7 In Examples 13 and 14 and Comparative Example 3, film formation and film evaluation were performed in the same manner except that Victrex 4800P was used in place of the polymer of Reference Example 1. The results are shown in Table V.

Claims (6)

[Claims] 1. An aromatic polysulfone molded article containing a water-insoluble polymer, wherein a hydrophobic part made of a water-insoluble substance and a hydrophilic part made of a water-soluble substance are covalently bonded to each other, A method for hydrophilizing a molded aromatic polysulfone, which comprises heat-treating at a temperature lower than the glass transition temperature of the group polysulfone. 2. An aromatic polysulfone, Or The method for hydrophilizing a molded aromatic polysulfone according to claim 1, which is a polymer having a repeating unit represented by: 3. A hydrophobic part consisting of a water-insoluble substance and a hydrophilic part consisting of a water-soluble substance, wherein the hydrophobic part is an aromatic polysulfone polymer or oligomer, and the hydrophilic part is a water-soluble polymer or oligomer. The method for hydrophilizing an aromatic polysulfone molded product according to claim 1, wherein 4. The method for hydrophilizing an aromatic polysulfone molded product according to claim 1, wherein the heat treatment is carried out in a state where the hydrophilic substance and the surface of the molded product are in contact with each other. 5. The method for hydrophilizing an aromatic polysulfone molded product according to claim 1, wherein the surface of the molded product is brought into contact with water or steam to perform heat treatment. 6. A heat treatment by contacting the surface of the molded product with a water-soluble substance which is a non-solvent of aromatic polysulfone, an aqueous solution thereof, vapor of the water-soluble substance, or vapor of the aqueous solution, and heat treatment. 5. A method for hydrophilizing a molded aromatic polysulfone according to the item.