JPH0694534B2 - Polyester molding having antibacterial properties - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polyester-based molded article having antibacterial properties. More specifically, the present invention relates to a polyester-based molded product containing zeolite-based solid particles retaining metal ions having a bactericidal action.

(Prior Art) It has long been known that silver ions, copper ions, zinc ions and the like have antibacterial properties. Therefore, some attempts have been made so far to retain these metal ions in a polymer to obtain a polymer molded product having antibacterial properties. For example, a method of adhering or adding a metal thin wire or powder to a polymer, a method of incorporating a metal compound into the polymer, and the like are known. As a method of incorporating a metal compound into a polymer, there is a method of incorporating an organic functional group having ion exchange ability or complex-forming ability into the polymer and retaining the metal ion in the organic functional group. The physical properties of the polymer are likely to change remarkably due to the interaction between the organic functional group and the polymer, and the type of the polymer that can be used and the type and amount of the organic functional group must be extremely limited. I don't get. On the other hand, there is a method of holding a metal ion having an antibacterial action in an inorganic solid particle having an ion exchange ability, and imparting this to a polymer, and in JP-A-59-133235, A method has been proposed which comprises zeolite-based solid particles and an organic polymer and holds at least a part of the zeolite-based solid particles a metal ion having a bactericidal action. Since this method basically adds inorganic solid particles having heat resistance, it has the advantage of excellent long-term thermal stability of antibacterial performance, but on the other hand, antibacterial performance is exhibited near the surface of the molded product. Since it is due to the antibacterial particles, the difference in the antibacterial performance may occur depending on the surface condition of the molded product, and particularly in the hydrophobic molded product such as the polyester-based molded product, there is a drawback that the performance varies. There is.

(Problems to be Solved by the Invention) Aromatic polyesters represented by polyethylene terephthalate are essentially hydrophobic. Therefore, even if the zeolite-based particles holding the metal ions having antibacterial properties are added and mixed in the molded body, the surface of the molded body is essentially hydrophobic and does not attract water, and the metal ions in the zeolite are activated. Often, they often do not work effectively.
For example, when considering a fiber as a molded body, if the fiber is washed with a metal soap, the hydrophobicity is further promoted, and this tendency is promoted, and finally the antibacterial performance may be lost. Also, for cleaning the surface of the molded body, after cleaning with an organic solvent,
The surface may be inactive and the antibacterial performance may be reduced. As a result of various studies in order to overcome such a phenomenon, it was found that the polyester containing metal-zeolite particles having antibacterial properties should be made hydrophilic to increase the affinity with water.

It is an object of the present invention to maintain good antibacterial performance and eliminate variations in performance in polyester-based moldings containing zeolite-based solid particles that retain metal ions having a bactericidal action.

(Means for Solving the Problem) The present invention relates to a molded product made of a hydrophilic copolyester containing zeolite-based solid particles retaining metal ions having a bactericidal action.

Representative examples of the metal ion in the present invention include metal ions having a bactericidal effect, such as Ag ⁺ , Cu ²⁺ and Zn ²⁺ . Further, metal ions having a bactericidal effect can be used alone or in combination of two or more kinds.

Zeolites shall apply generally amino silicate having a three-dimensionally developed skeletal structure, generally represented by with respect to the _{Al 2 O 3 XM 2 / n} O · Al 2 O 3 · ySiO 2 · ZH 2 O. M represents an ion-exchangeable metal ion, and usually has a valence of 1 to 2.
It is a valent metal, and n corresponds to this valence. On the other hand, X and y represent the coefficient of metal oxide and silica, and z represents the number of crystal water. Many types of zeolites are known, which differ in composition ratio, pore size, specific surface area, and the like.

However, the zeolite-based solid particles used in the present invention have a specific surface area of 150 m ² / g (anhydrous zeolite basis) or more, and the SiO ₂ / Al ₂ O ₃ molar ratio of the zeolite constituents is preferably 14 or less, and 11 or less. More preferable.

A solution of a water-soluble salt of a metal ion having bactericidal activity, such as silver, copper and zinc, is easily ion-exchanged with zeolite. Therefore, by utilizing such a phenomenon, the required metal ion is retained in the zeolite stationary phase. This is because it becomes possible to do so. For example, in a zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of 14 or less, it is possible to uniformly hold metal ions having a bactericidal action. In addition, the SiO ₂ / Al ₂ O ₃ molar ratio of the zeolite has a high silica ratio of more than 14 acid resistance, alkali resistance increases with the increase of SiO ₂ , on the other hand, it takes a long time to synthesize it. Economically, it is not a good idea to use such a high silica ratio zeolite. The above-mentioned SiO ₂ / Al ₂ O ₃ ≦ 14 natural or synthetic zeolite can be sufficiently used in terms of acid resistance and alkali resistance in the normally considered application fields of this structure, and economically. Is cheap and a good idea. From this point of view, the SiO ₂ / Al ₂ O ₃ molar ratio is preferably 14 or less.
Therefore, SiO ₂ / A known as molecular sieve
Zeolites having a large l ₂ O ₃ molar ratio are not preferred in the present invention.

As the zeolite material having a SiO ₂ / Al ₂ O ₃ molar ratio of 14 or less, either natural or synthetic zeolite can be used. For example, natural zeolite
alcime: SiO ₂ / Al ₂ O ₃ = 3.6-5.6), chabasite (Chaba
_{zite: SiO 2 / Al 2 O} 3 = 3.2~6.0 , and 6.4 to 7.6), clinoptilolite _{(Clinoptilolite: SiO 2 / Al 2} O 3 = 8.5~10.
5), Erionite (SiO ₂ / Al ₂ O ₃ = 5.8 to 7.
4), Faujasite: SiO ₂ / Al ₂ O ₃ = 4.2-4.
6), mordenite _{(Mordenite: SiO 2 / Al 2} O 3 = 8.34~10.
0), Phillipsite: SiO ₂ / Al ₂ O ₃ = 2.6
~ 4.4) and the like. These typical natural zeolites are suitable for the present invention. On the other hand, a typical type of synthetic zeolite is an A-type zeolite (SiO ₂ / Al ₂ O ₃ = 1.4-
2.4), X-type zeolite (SiO ₂ / Al ₂ O ₃ = 2 to 3), Y-type zeolite (SiO ₂ / Al ₂ O ₃ = 3 to 6), mordenite (Si
O ₂ / Al ₂ O ₃ = 9 to 10) and the like, and these synthetic zeolites are also suitable as the zeolite material of the present invention.

The metal ions must be retained in the zeolite solid particles by an ion exchange reaction. If the substance is simply adsorbed or adhered without using ion exchange, the bactericidal effect and its sustainability are insufficient. The binding force between zeolite and antibacterial metal ions such as silver, copper and zinc is different from the method in which it is simply held by physical adsorption on an adsorbent such as activated carbon or alumina.
The strong bactericidal capacity of the moldings, which are very large and thus contain such metal-zeolites, and their long-term persistence are noteworthy as characteristic advantages of the invention. For example, A-type zeolite, X-type zeolite, Y-type zeolite,
Ion-exchangeable metal ions (Na ⁺ ) in chabazite
Easily exchanges ions with Ag ⁺ , Cu ²⁺ or Zn ²⁺ ,
It retains germicidal metal ions in the matrix of zeolite and has a high ability to retain them. It also has the advantage that it has a large selective adsorption property for Ag ⁺ , Cu ²⁺ and Zn ²⁺ . Such fact, the liquid containing various metal ions for the purpose of sterilizing the zeolite particle-containing molded article of the present invention, even when used in water Ag ⁺ , Cu 2 ⁺ , Z
It means that n ²⁺ is stably retained in the zeolite matrix for a long period of time, and the bactericidal activity is maintained for a long period of time.

In addition, the zeolite has an advantage that it has a large exchange capacity and can increase the retention amount of Ag ⁺ , Cu ²⁺ and Zn ²⁺ having bactericidal activity. Further, depending on the intended use of the zeolite particle-containing molded article of the present invention, it is contained in the zeolite solid particles
There is an advantage that the amount of Ag ⁺ , Cu ²⁺ and Zn ²⁺ can be easily adjusted by ion exchange.

The amount of metal in the metal-zeolite (based on anhydrous zeolite) is preferably 30% by weight or less for silver, and more preferably 0.001 to 5% by weight. On the other hand, regarding copper and zinc used in the present invention, the amount of copper or zinc in the metal-zeolite (anhydrous zeolite basis) is preferably 35% by weight or less, more preferably 0.01 to 15% by weight. When silver, copper and zinc ions are used in combination, the total amount of metal ions may be 35% by weight or less with respect to the metal-zeolite (anhydrous zeolite basis), and the preferable range depends on the composition ratio of the metal ions, but is about 0.001. ~ 15
% By weight.

Further, even if metal ions other than silver, copper, and zinc, such as sodium, potassium, calcium, or other metal ions coexist, the bactericidal effect is not impaired, so that these ions may remain or coexist at all.

The shape of zeolite is preferably powder particles, and the particle diameter may be appropriately selected according to the application. When applied to various containers, pipes, granules or fibers of thick denier, the thick molded product may have a size of several microns to several tens of microns or several hundreds of microns or more, while it is molded into fine denier fibers or film. In this case, it is desirable that the thickness is 5 microns or less, especially 2 microns or less.

The hydrophilic copolyester used in the present invention is an aromatic polyester, such as polyethylene terephthalate or polybutylene terephthalate, which is hydrophilized. There are two ways to make it hydrophilic. One of them is to introduce a substance having an affinity for water as a copolymerization component into the polyester polymer used in the present invention. Suitable copolymerization components include those having a molecular weight of 10,000 or less,
It is preferably 4,000 or less, more preferably 2,000 or less polyethylene glycol and / or sodium sulfoisophthalate. In the case of polyethylene glycol, the copolymerization ratio is at least 2% by weight or more, preferably 4% by weight or more and 20% by weight or less based on the copolymer. In the case of sodium sulfoisophthalate, it is 1 mol% or more, preferably 2 mol% or more and 20 mol% or less with respect to the acid component. If the copolymerization exceeds the limit, the mechanical and physical properties of the molded product cannot be maintained. Furthermore, it is effective to use polyethylene glycol and sodium sulfoisophthalate together.

The second method of hydrophilizing is to introduce the hydrophilizing copolymer as a polymer blend at the time of molding the polyester-based molded body. For example, there is a method in which a polyester ether composed of 8% by weight of a polyethylene terephthalate component and 92% by weight of polyethylene glycol having a molecular weight of 1000 is blended with polyethylene terephthalate or polybutylene terephthalate and a polymer to form a molded body. It is more effective if the zeolite-based solid particles having antibacterial properties are previously dispersed in the polymer rich in the hydrophilic component and then polymer-blended at the time of molding.
Further, if the zeolite-based solid particles having antibacterial properties are previously dispersed in the hydrophilic component-rich polymer, and when blending with the polyester at the time of molding, the zeolite-containing polymer can be produced in a number of fine streaks, in particular, It becomes effective. The hydrophilic copolymer that can be used in the second method is polyethylene glycol or sodium sulfoisophthalate having a molecular weight of 10,000 or less, preferably 4,000 or less, more preferably 2,000 or less. The copolymerization ratio should be at least 2% by weight or more, preferably 4% by weight or more and 20% by weight or less when the component ratio in the final hydrophilic polyester is polyethylene glycol. In this case, it may be selected so as to be 1 mol% or more, preferably 2 mol% or more and 20 mol% or less with respect to the acid component. If the ratio is increased above the limit, the mechanical properties of the molded product cannot be maintained. Furthermore, it is effective to use polyethylene glycol and sodium sulfoisophthalate together.

Whichever method is used for hydrophilicity, a surfactant such as sodium dodecylbenzene sulfonate may be mixed in the hydrophilic copolymer within a range of 5% by weight or less.

In the molded body of the present invention, the proportion of the zeolite-based solid particles holding metal ions having a bactericidal action is 0.
01 to 50% by weight (anhydrous zeolite basis) is preferred. When the amount is less than the above lower limit, the bactericidal effect is unsatisfactory. On the other hand, even if the amount exceeds the above upper limit, the bactericidal effect remains almost unchanged, and the physical properties of the molded product change significantly, limiting the use as a molded product. From this viewpoint, the more preferable content range is 0.05 to 40% by weight, and when the particle-containing molded product of the present invention is used in the form of fibers, the range of 0.05 to 10% by weight is preferable.

The timing and method of addition and mixing are not particularly limited. For example, a method of adding and mixing to raw material monomers and then polymerizing, a method of adding and mixing to a reaction intermediate, a method of adding and mixing to a polymer at the time of completion of polymerization, a method of adding and mixing to polymer pellets and molding, and previously dispersing in another suitable vehicle. Then, there are a method of press-fitting and adding at the time of molding, a method of adding and mixing to a dope for molding, for example, a spinning dope. For the sake of simplicity, these methods will be simply referred to as "adding and mixing to a molded body" below. The point is that an optimal method may be adopted depending on the properties of the polymer to be used, the characteristics in the process, and the like. Usually, a method of adding and mixing immediately before molding is suitable. However, in some cases, it may be preferable to add and mix with the monomer for good dispersion of the particles. The metal-zeolite is dried before being added to the molded body. Drying conditions are normal pressure or reduced pressure,
It may be appropriately selected within the range of 100 to 500 ° C. Preferred drying conditions are 100 to 350 ° C. under reduced pressure.

Since the zeolite particle-containing molded product of the present invention is mainly composed of polyester, it can be molded into various shapes and sizes. For example, granules, films, fibers, various containers, pipes, and any other molded body can be used, and can be used in an extremely wide range of applications requiring sterilizing power.

The zeolite particle-containing molded product of the present invention may contain, for example, a polymerization catalyst, a stabilizer, a matting agent, a whitening agent, an organic or inorganic pigment, an inorganic filler and various plasticizers.
Further, it may contain a liquid or an organic solvent.

The method of distributing the metal-zeolite in the molded body may be appropriately devised, but as described above, the sterilizing power of the molded body of the present invention is considered to mainly depend on the amount of metal ions near the surface of the molded body. Therefore, for example, there is a method in which the zeolite of the present invention is contained in the outer layer of a multilayer structure. In the case of fibers, a core-sheath metal having an antibacterial property as a sheath component of a yarn cross-section is formed by utilizing a known conjugate spinning technique.
It can contain zeolite.

Further, the molded product comprising the zeolite particle-containing molded product of the present invention can be used as a mixture or a composite with the same and different types of molded products. For example, in the case of fibers, it is possible to make an antibacterial fiber structure in which the texture and the function are widely changed by mixing, mixing, weaving, or knitting with a fiber containing no metal-zeolite.

(Example) Hereinafter, the Example of this invention is described. In the examples, the bactericidal effect was evaluated by the following test methods.

<Evaluation test method of antibacterial activity> An antibacterial activity test was conducted by the disc method. That is, the zeolite particle-containing molded body was cut into a disk having a diameter of 20 m / m to obtain a test disk. Es of bacteria as test organism
cherichia coli, Pseudomonas aeruginosa, Staphyloco
We used ccus aureus and Candida albicans as the fungus. Mueller Hinton medium for bacteria,
For fungi, Sabouraud medium was used. The test bacteria were suspended in physiological saline at 10 ⁸ cells / ml and dispersed in the medium with a 0.1 ml conradi stick. Next, the test disk was stuck on it.

In determining the antibacterial activity, bacteria were kept at 37 ° C for 18 hours and cultured, and then observed for the presence of inhibition zone formation. On the other hand, fungi were kept at 30 ° C for 1 hour and incubated for 1 hour after incubation. The presence or absence was observed.

Examples 1 to 9 and Comparative Examples 1 to 6 Commercially available synthetic A-type zeolite, X-type zeolite, Y-type zeolite and natural mordenite were pulverized to have an average particle size of 0.6.
～1.5Myuemu, to obtain a zeolite four specific surface area 180~900m ² / g.

Each 250 g of these zeolite powders was added to 1 / 10M silver nitrate aqueous solution (I), 1 / 20M copper sulfate aqueous solution (II) or 2M zinc chloride aqueous solution (III) 1 each, and the resulting mixture was stirred at room temperature for 5 hours ( (I) and (II)) or about 60 ° C. for 5 hours ((III)). The silver zeolite, copper zeolite or zinc zeolite obtained by such ion exchange was recovered by centrifugation, washed with water to remove excess metal ions, dried at 100 to 105 ° C., and then pulverized to obtain a fine powder. . The metal zeolite thus obtained is shown in Table 1.

As a comparative control (a), A type zeolite undried fine powder 25
0 g was taken, 1 M copper sulfate aqueous solution 1 was added, and the mixture was stirred at room temperature for 5 hours. Then, after suctioning, the product was washed with water until the sulfate ion disappeared and dried and ground at 100 to 105 ° C.
Cu ₃ (SO ₄ ) (OH) ₄ was precipitated and mixed in the zeolite type.

As a comparative control (b), the above-mentioned zeolite without metal addition was also dried at 105 ° C. and re-ground.

Next, the above various metal zeolites were dried under reduced pressure at 200 ° C. for 7 hours and subjected to the following spinning test. That is, a polyethylene terephthalate dried chip (abbreviated as PET) with an intrinsic viscosity of 0.640 measured at 20 ° C in a phenol / ethane tetrachloride (6/4) mixed solvent, or a polyethylene glycol with the same intrinsic viscosity of 0.620 and a molecular weight of about 600 ( 7% by weight
Copolymerized polyethylene terephthalate dry chips (abbreviated as EDP), further, an intrinsic viscosity of 0.650, polyethylene terephthalate dry chips copolymerized with 3.5 mol% sodium sulfoisophthalate (abbreviated as CDP), and a relative viscosity of 2.50. To each of polybutylene terephthalate chips (abbreviated as PBT), 6 wt% of the above-mentioned dry metal zeolite was added, melt-mixed at 280 ° C., extruded in a gut shape, and cut by cooling to obtain 20 kinds of master chips. It was Next, the master chip and the polystyrene terephthalate chip to which the metal zeolite has not been added are dried at 130 ° C. under reduced pressure until the water content becomes 0.01% or less, and then supplied to an extruder at a ratio of 1: 2 for spinning / stretching, A drawn yarn of 75 denier 24 filaments with a round cross section was obtained. As a control, an ordinary polyethylene terephthalate 75-denier 24-filament stretched yarn containing no metallic theolite was experimentally manufactured.

Each of these draws was made into two knitting yarns and scoured by a cylinder knit, and then Esch
erichia coli, Pseudomonus aeruginosa, Staphylococc
Antibacterial activity against us aureus and Candida albicans was measured. Further, the tubular knitted fabric was washed 20 times according to JIS L-0217 (method 150) and the antibacterial activity was examined. The results of these antibacterial performance tests are shown in Table 2.

As is clear from Table 2, the tubular knitted fabric of hydrophilic polyester to which 2.0% by weight of the metal zeolite retaining silver, copper and zinc by ion exchange is added has sufficient antibacterial properties even before and after 20 washings. Had. On the other hand, in the case of the PET or PBT tubular knit fabric, the antibacterial property disappeared after washing 20 times. Further, the metal zeolite comparative control (a) to which copper was added did not have sufficient antibacterial activity even before washing, regardless of ion exchange.

(Effects of the Invention) As described above, the present invention is a molded article having no variation in antibacterial performance during molding and excellent in long-term sustainability of the performance.

Claims (3)

[Claims] 1. A polyester-based molded article having antibacterial properties, which comprises a hydrophilic copolyester containing zeolite-based solid particles retaining metal ions having a bactericidal action. 2. The molded product according to claim 1, wherein the metal ion having a bactericidal action is one or more metal ions selected from the group consisting of silver, copper and zinc. 3. The molded product according to claim 1, wherein the hydrophilic copolyester has an ethylene terephthalate unit or a butylene terephthalate unit as a main component and is copolymerized with polyethylene glycol and / or sodium sulfoisophthalate.