JPS629133B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polyester molded articles, particularly polyester molded articles having sterilizing properties.

With the development of polymer chemistry, various synthetic polymers have come to be manufactured, and today they have become essential materials for various uses. Among them, polyesters, especially polyesters containing aromatic dicarboxylic acids as acid components, are widely used as molded products such as films, fibers, and sheets due to their excellent physical properties. Although modifications have been made, there are fields in which additional special functions are required. One of them is bactericidal properties. On the other hand, it has been known for a long time that iodine has strong toxicity against microorganisms, in other words, it has an excellent bactericidal effect, and is used as an external medicine such as iodine tincture. Utilizing this, attempts have been made to manufacture polymer molded products with bactericidal properties by incorporating iodine into polymer molded products. A method has been proposed in which iodine is adsorbed by immersion in a potassium aqueous solution.

However, although iodine can be easily incorporated in this method, it is not preferable because it causes a change in crystal form due to the breakage and rearrangement of hydrogen bonds between polyamide chains, and a decrease in strength, which is thought to be due to the formation of defects. On the other hand, polyesters that do not have such hydrogen bonds are said to not adsorb iodine. (Tokukai Akira
54-91572) As a method of imparting bactericidal properties, a method has also been proposed in which an antibacterial compound having an ionic group, such as sarconium chloride, is bonded to a polymeric material via an acidic group to improve durability.
However, when this method is applied to polyester, it is necessary to introduce acidic groups into the polyester in advance, which is undesirable because the physical properties deteriorate.

The present inventors have conducted intensive research on a method for imparting sterilization properties to polyester molded products without deteriorating their physical properties, and by treating them with an aqueous iodine solution under specific temperature conditions, 6. It was discovered that iodine could be contained in polyester molded articles, and as a result of further detailed study, the present invention was achieved.

That is, in the present invention, a molded article made of polyester is placed in an aqueous solution containing iodine according to the formula Tg-10≦T≦6/7Tg+30 (1) [where Tg: glass transition temperature of polyester (°C) T: treatment temperature (°C) )] Iodine is treated in the temperature range shown in
This is a method for producing a polyester molded article characterized by containing 30% by weight.

The polyester used in the present invention is a polyester containing terephthalic acid as the main acid component and ethylene glycol, tetramethylene glycol, cyclohexanedimethanol, etc. as the main glycol component. In addition to terephthalic acid, aromatic dicarboxylic acids such as isophthalic acid, naphthalene dicarboxylic acid, diphenylsulfone dicarboxylic acid, and biphenyl dicarboxylic acid, or aliphatic dicarboxylic acids such as adipic acid and sebacic acid may be contained. Dihydroxy compounds such as diethylene glycol, polyethylene glycol, and bisphenol A may be included as glycol components. Further, oxycarboxylic acids such as oxybenzoic acid and hydroxyethoxybenzoic acid may be included. Any known method and any catalyst can be used to produce such polyesters.

That is, the above-mentioned carboxylic acid or an ester-forming derivative thereof may be reacted with a glycol by a known method.

The iodine concentration in the iodine aqueous solution used in the present invention is preferably 1 to 20% by weight. As is well known, the solubility of iodine in water is low (0.078 g/100 g of water at 50°C), so a solubilizing agent is required to obtain an aqueous solution of such concentration. Among the iodides, potassium iodide is suitable as the solubilizing agent.

The treatment temperature with the iodine aqueous solution, which is one of the features of the present invention, is within the range defined by the above formula (1). The glass transition temperature referred to herein is the temperature determined from the shift of the baseline of the differential thermal curve to the endothermic side, which was measured by differential thermal analysis at a heating rate of 10° C./min. If the treatment temperature is lower than the above range, as previously known, iodine will not be adsorbed, or even if it is adsorbed, the adsorption rate will be extremely low, and it will be adsorbed only to the surface layer of the molded product, resulting in poor durability and long-lasting effects. . If the treatment temperature is higher than the above range, not only the physical properties of the molded article will significantly deteriorate, but also the amount of adsorption will decrease. The amount of iodine contained in the polyester molded article is 0.1 to 30% by weight, preferably 0.5 to 20% by weight. If the amount of iodine is less than 0.1% by weight, permanent sterilization cannot be obtained, and if it exceeds 30% by weight, the initial amount of iodine released will be too large, increasing the amount of iodine that escapes into the atmosphere, which will affect sterilization. This is not preferable because the effective iodine ratio decreases and the negative impact on the surroundings increases.

The treatment time with the iodine aqueous solution varies depending on the iodine concentration in the aqueous solution, the treatment temperature, and the required amount of iodine adsorption, but is usually preferably 5 to 120 minutes. Although the amount of adsorption can be controlled by adjusting the treatment temperature and treatment time, it is preferable to control the iodine concentration in the aqueous solution, particularly the amount of an iodine solubilizer, such as potassium iodide.

Polyester molded products treated by the above method can be used by washing with water and drying after treatment, but in order to remove iodine adsorbed on the surface of the molded product, a sodium thiosulfate aqueous solution is used to remove the iodine at a temperature below the treatment temperature with the iodine aqueous solution. It is preferable to wash with

The method of the present invention will be specifically explained below with reference to Examples.

Example 1 A knitted sock made using polyethylene terephthalate long fibers (75 denier, 24 filaments) produced by a conventional method was immersed in an aqueous solution containing 70 g of iodine and 100 g of potassium iodide, and heated to 70°C while stirring gently. After treating with water for 1 hour, it was washed with running water at room temperature for 5 minutes and with a 3.8% sodium thiosulfate aqueous solution for 30 minutes, and air-dried overnight to obtain an iodine adsorption amount of 5.2%.
A brown polyester knitted fabric was obtained. A 3cm x 3cm test piece was cut out, and a culture test was conducted for 24 hours at 37°C on an FDA agar medium in accordance with AATCC-6538 to determine its bactericidal activity against Staphylococcus aureus. As a result, an excellent inhibitory effect was observed. On the other hand, in the culture medium using untreated polyester knitted fabric, no difference was observed between the test piece contact area and the non-contact area.

Example 2 Polyester produced by a conventional method (5 mol% isophthalic acid copolymerized polyethylene terephthalate)
Biaxially stretched film (thickness 12μ) with 150g of iodine/
, in an aqueous solution containing 300 g of potassium iodide at 80°C.
3.8 After soaking for 30 minutes, soak in running water at room temperature for 5 minutes.
% sodium thiosulfate aqueous solution for 20 minutes and air-dried overnight to obtain a brown polyester film with an iodine adsorption amount of 8.7%. A 3 cm x 3 cm test piece was cut out and a bactericidal property test was conducted in the same manner as in Example 1. As a result, an excellent inhibiting effect was observed.

Claims (1)

[Claims] 1 A molded article made of polyester is placed in an aqueous solution containing iodine using the formula Tg-10≦T≦6/7Tg+30 (1) [In the formula, Tg: glass transition temperature of polyester (°C) T: treatment temperature ( ℃）〕 in the temperature range shown in
A method for producing a polyester molded product characterized by containing 30% by weight.