KR20120112968A - Method for preparing polyurethane film comprising apatite with high antibacterial function - Google Patents

Abstract

PURPOSE: A manufacturing method of a polyurethane composite film is provided to provide a polyurethane film with improved silver ion dipping ability and antibiosis by controlling a particle size of hydroxyapatite. CONSTITUTION: A manufacturing method of a polyurethane composite film comprises: a step of preparing a polyurethane solution; a step of preparing nano-sized hydroxyapatite dispersion; a step of preparing polyurethane/apatite composite composition by mixing hydroxyapatite into the polyurethane solution; a step of preparing polyurethane microbeads-containing polyurethane composition by putting a water/organic solvent mixture into the composite composition; a step of preparing a polyurethane composite film by film casting the polyurethane composition; and a step of absorbing silver ion by impregnating the polyurethane composite film into the silver nitrate solution.

Description

Method for Preparing Polyurethane Film Comprising Apatite with High Antibacterial Function

The present invention relates to a method for producing a microporous polyurethane film having excellent antimicrobial properties, and in particular, a polyurethane microbead is developed in the film, and a polyurethane film having excellent moisture permeability and antimicrobial properties by combining apatite for supporting silver ions. It relates to a method of manufacturing.

The moisture-permeable waterproof polyurethane film has the property of allowing air to pass through without passing water, and thus is used for sportswear such as mountain climbing clothes, protective clothing such as fire fighting clothing, and the like. On the other hand, by imparting antimicrobial property to the moisture-permeable waterproof polyurethane film, it is applied to wound protection dressings, antibacterial sheets, or patient clothing.

There are many known materials for imparting antimicrobial properties. For example, various types of inorganic antibacterial agents using zeolite, apatite hydroxide, zirconium phosphate, and silica gel are known. Such an inorganic antimicrobial agent is a substitute for a metal ion having excellent antimicrobial activity in an inorganic material, and has a three-dimensional structure, and thus has a large specific surface area and excellent heat resistance.

Among the inorganic antimicrobial agents, hydroxide apatite (Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ : HAp) is used as an implant material such as artificial bones or artificial teeth in the medical and dental fields because of its excellent biocompatibility and ion exchange ability. In the environmental field, it is also used to remove heavy metals as ion exchange resin.

As an excellent antimicrobial metal, mercury and silver salts and organic compounds thereof have strong antibacterial properties. However, mercury is harmful to the human body, so antibacterial and harmless to the human body is used a lot of silver.

Prior art related to the method of producing a polyurethane film is as follows.

Korean Patent No. 10-096702 discloses a method for producing a non-swellable polyurethane bead cone film. In this patent, a polyurethane beadcon film was prepared using a polyurethane composition composed of a hydrophilic polyurethane resin, ceramic fine particles, and a plurality of solvents.

Korean Patent No. 10-0690356 discloses a method for preparing hydroxyapatite and polyurethane composite foam. The patent provides a method for producing a hydroxyapatite / polyurethane composite foam using polyurethane as a binder.

In general, in the case of antimicrobial minerals, the smaller the particle size, the higher the antimicrobial effect. In the present invention, to adjust the particle size of the apatite hydroxide to provide a polyurethane film having a silver ion carrying capacity and antibacterial properties.

An object of the present invention is to provide a moisture-permeable waterproof polyurethane film having excellent antimicrobial properties by adsorbing silver ions to the hydroxide of the particle size is adjusted.

In order to solve the above problems, according to a preferred embodiment of the present invention, the step of putting a hydrophilic polyurethane resin in an organic solvent to prepare a polyurethane stock solution;

Preparing a nano hydroxide apatite dispersion having an average particle size of 100 to 200 nm by pulverizing the apatite by adding an apatite hydroxide to an organic solvent; Preparing a polyurethane / apatite composite composition by stirring the apatite hydroxide dispersion into the polyurethane stock solution; Preparing a film-forming polyurethane composition in which water / organic solvent mixture is added to the composite composition to form polyurethane microbeads; Manufacturing a polyurethane composite film by film casting the polyurethane composition; And immersing the polyurethane composite film in a silver nitrate solution to adsorb silver ions.

According to another suitable embodiment of the present invention, the apatite hydroxide is characterized in that it contains 0.5 to 10% by weight relative to the total weight of the polyurethane composition.

According to another suitable embodiment of the present invention, the apatite hydroxide is characterized in that it is put in an organic solvent using a probe-type ultrasonic disperser and pulverized for 5 to 20 minutes.

According to another suitable embodiment of the present invention, the water / organic solvent mixture is characterized in that the mixing weight ratio of 9: 1 to 8: 2.

Polyurethane composite film produced in the present invention is excellent in antibacterial because silver ions are adsorbed well to the hydroxy apatite having a small particle size. Polyurethane film prepared in the present invention is a polyurethane microbeads of about 1㎛ before the film formation step has a structure that has excellent moisture permeability, it can be used in antimicrobial moisture-permeable waterproof film, wound protection patches, hospital antibacterial sheet and patient clothing Can be.

1 is a SEM photograph of the polyurethane film produced in the present invention. (a) is a film in which only beads are formed without apatite, and (b) is a cross-sectional photograph of a film in which 5% of solids is contained in weight ratio of apatite particles ultrasonically pulverized with bead formation.
Figure 2 shows the EDS spectrum after supporting silver on the polyurethane film prepared in the present invention, showing that the silver (Ag) ions are supported together with the calcium (Ca) ions of the apatite.
3 shows the distribution of apatite hydroxide particles before sonication.
Figure 4 shows the distribution of the apatite hydroxide particles after treatment for 5 minutes by ultrasonic.

Method for producing a waterproof moisture-permeable polyurethane film excellent in the antimicrobial properties of the present invention comprises the steps of putting a hydrophilic polyurethane resin in a solvent to prepare a polyurethane stock solution (S11); Adding apatite hydroxide to the mixed organic solvent and pulverizing the apatite hydroxide through ultrasonication to prepare apatite hydroxide dispersion (S12); Preparing a polyurethane / apatite composite mixed solution by adding the apatite hydroxide dispersion into the polyurethane stock solution and stirring the mixture (S13); Preparing a film-forming polyurethane composition in which water / organic solvent mixture is added to the complex mixture to form polyurethane microbeads (S14); Manufacturing a polyurethane composite film by film casting the polyurethane composition (S15); And immersing the polyurethane composite film in a silver nitrate solution to adsorb silver ions (S16).

Hereinafter, the process according to each step will be described in detail.

First, a hydrophilic polyurethane resin is put in a solvent to prepare a polyurethane stock solution (S11). The polyurethane stock solution is prepared by mixing a hydrophilic polyurethane resin with a solvent that is generally used, and as the solvent, dimethylformamide (DMF), methyl ethyl ketone (MEK), toluene, etc. may be preferably used. The polyurethane stock solution is a polyurethane stock solution consisting of 20 to 40 parts by weight of a hydrophilic polyurethane resin, 60 to 80 parts by weight of a solvent.

Next, apatite hydroxide is added to a mixed solvent which is a dilution solution of polyurethane, and the apatite hydroxide is pulverized through ultrasonication to prepare apatite hydroxide dispersion (S12). In the mixed solvent, at least two solvents selected from the group consisting of DMF, MEK, and toluene are preferably mixed at 1: 1 to 1.5: 1 (weight ratio).

Generally, the apatite hydroxide synthesized by precipitation from calcium hydroxide and phosphoric acid has a particle size of 1 to 3 μm. The antimicrobial property is a property that occurs on the surface of the antimicrobial agent, and the smaller the particle size of the apatite that adsorbs silver ions, the larger the surface area is, so the antimicrobial performance is excellent.

Apatite by the precipitation method is very difficult to pulverize the particles even when treated with ultrasonic waves due to severe aggregation in the polar medium of water. However, in the present invention, the particle size of the apatite hydroxide can be pulverized up to 100-200 nm by adding an apatite hydroxide to a mixed solvent of DMF, MEK, and toluene, which are used as a diluting solution of the polyurethane stock solution. By grinding the particle size of the apatite hydroxide to 100 ~ 200nm it can be uniformly dispersed in the polyurethane solution can exhibit excellent antimicrobial properties in the finally produced film. In addition, since the particle size is 1 µm or less, the ability to carry silver ions is also excellent. In the above ultrasonic treatment is preferably treated for 5 to 20 minutes using a 750W probe type ultrasonic disperser. Figure 3 shows the particle distribution of the apatite hydroxide before (a min min) before the ultrasonic treatment with apatite hydroxide in the MEK solution, the apatite hydroxide particles before the ultrasonic treatment has an average particle size of 1 ~ 3㎛. Figure 4 shows the particle distribution of the apatite hydroxide after the addition of apatite hydroxide to the MEK solution and treated for 5 minutes by ultrasound, having an average particle size of 100 ~ 200 nm. The content of the apatite hydroxide in the polyurethane composition for forming a film is preferably 0.5 to 10% by weight based on the total weight of the composition.

In the present invention, it is preferable to adjust the particle size of the apatite hydroxide to 100 ~ 500nm or less using an ultrasonic disperser. When the particle size has a nano-size distribution, not only the silver ion supporting ability and the antibacterial property are excellent, but also it is advantageous to maintain physical properties in the preparation of moisture-permeable waterproof polyurethane film having a thickness of several tens of μm.

Next, the nano-apatite composite polyurethane solution is prepared with stirring while slowly adding the apatite hydroxide dispersion into the polyurethane stock solution (S13). At this time, the mixing ratio of the polyurethane stock solution and the apatite hydroxide dispersion is preferably 2: 1 to 3: 1. At this time, considering the proper ratio of polyurethane / solvent in the final film forming solution, if the ratio of the polyurethane stock solution is lower than this, the viscosity of the polyurethane stock solution is too high, making it difficult to efficiently mix with the apatite dispersion. The amount of solvent in the dispersion is reduced, making it difficult to produce an efficient apatite dispersion.

Next, a water / organic solvent mixture is added to the complex mixture to prepare a polyurethane composition for film formation in which polyurethane microbeads are formed (S14). At this time, the bead formation structure is changed according to the ratio of the water / organic solvent mixture solution and thus the moisture permeability is affected. In order to form an effective polyurethane microbead, it is preferable that the mixing weight ratio of water / solvent is 9: 1-8: 2. In this case, the solvent may be DMF or MEK. If only pure water is used without mixing the solvent, the bead formation is so clear that the moisture permeability can be higher, but there is a disadvantage in that the film properties are deteriorated due to no connection between the beads.

Next, the polyurethane composition is film cast to prepare a polyurethane composite film (S15). The film casting method may use a known method, for example, by performing a film casting on a release paper by a knife method and gradually drying stepwise to 80 ~ 120 ℃ over 5 to 20 minutes in a dryer. The dried polyurethane film is a microbead is formed as shown in Figure 1 to be a porous composite film excellent in moisture permeability.

Finally, the polyurethane composite film is immersed in a silver nitrate solution for 30 seconds to 5 minutes to adsorb silver ions (S15). At this time, the silver nitrate solution is preferably 50 ~ 200ppm concentration. By immersing the polyurethane composite film containing apatite in the silver nitrate aqueous solution, silver ions are mainly adsorbed on the surface of the film. In this case, antibacterial ability is given only to the surface of the film to minimize the consumption of silver. The antibacterial property is excellent.

In the present invention, a film comprising nanosize apatite hydroxide is prepared first, and then silver ions are supported on the surface of the film which exhibits antimicrobial activity as compared with a method of combining apatite bearing silver ions in advance by adsorbing silver ions. Inactivity of is characterized by minimizing the amount of ions.

The antimicrobial test of the polyurethane composite film produced in the present invention was carried out by the following method.

The antimicrobial test was conducted by shaking flask method according to the antimicrobial activity test method of KS J 4206: 2008 antimicrobial function product. The culture was contacted with the sample and the culture medium and the CFU (Colony forming unit) was measured to evaluate the antimicrobial activity. Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 6538) and Klebsiella pneumoniae (ATCC 4352) were used as test bacteria. As a nutrient medium, Bacto-peptone 5g, Beef extract 3g, 1,000 ml of distilled water, pH 6.8 ± 0.2 (25 ℃) was used. The antimicrobial activity was evaluated by inoculating the test bacteria into the antimicrobial processed sample and the control sample, and after culturing, measuring the number of viable cells, and calculating the bacteriostatic reduction rate comparing the bacterial counts of the antimicrobial processed sample and the control sample using the following equation.

[Formula 1]

M _a : Number of bacteria immediately after inoculation of the control sample (initial value) (average value)

M _b : Number of bacteria in control sample after incubation for 24 hours (average value)

M _c : Number of bacteria in the test sample after 24 hours incubation (average value)

In the present invention, the water vapor transmission rate is about 7 cm in diameter according to the KS K0594 (CaCl ₂ method) to take a concentric circle with respect to the moisture-permeable cup and put the packing and the ring sequentially and fixed with a butterfly nut and mounting side vinyl adhesive tape It is sutured to make a test specimen. The test body was placed in a 40 ± 2 ° C, 90 ± 5 ° C, RH thermo-hygrostat and the weight of the test body after 1 hour (A ₁ ) and the weight of the test body after 1 hour (A ₂ ) were measured. Permeability was calculated using. S is a water vapor transmission area of about 28.3 cm ³ .

[Formula 2]

Moisture permeability ^{(g / m 2? 24h)} = {10 × (A 2 -A 1)} / S × 24hr

Hereinafter, the present invention will be described in detail with reference to Examples, but the scope of the present invention is not limited by the following Examples.

Example 1

A polyurethane stock solution (manufactured by Cytec) consisting of 30 g of hydrophilic polyurethane resin (PU) and 70 g of methyl ethyl ketone (MEK) was prepared. As a dilution solution of the polyurethane stock solution, 18 g of MEK and 15 g of toluene were mixed, and 1 g of apatite hydroxide (manufactured by Samzo Industries, ST-100 Apatite) was added thereto, and treated with 750 W probe type ultrasonic dispersion machine (Ultra0Sonic Homonizer VCX 750) for 5 minutes. To prepare a dispersion dispersed in 100 ~ 200nm, and then mixed with the polyurethane stock solution to prepare an apatite composite polyurethane composition. The mixture of 45 g of non-solvent water and 5 g of MEK 5g is added in small portions to the apatite composite polyurethane composition with sufficient agitation so that the polyurethane partially coagulates with water, resulting in microbeads as shown in FIG. 1. A PU composition for film was prepared. The apatite composite PU composition for a film was prepared by stirring while slowly adding 51 g of the apatite hydroxide dispersion to 133 g of the PU solution for film. The PU composition was film cast on a release paper by a knife method and slowly dried while raising the temperature to 80-120 ° C. for 10 minutes in a dryer. The prepared composite film was immersed in 1 L of 100 ppm of silver nitrate aqueous solution for 1 minute to adsorb silver. EDS spectrum of the prepared composite film is shown in FIG. 2, it can be seen that silver is successfully adsorbed on the composite film. The moisture permeability and antimicrobial properties of the prepared polyurethane composite films are measured and shown in Table 1.

Example 2

A polyurethane composite film was prepared in the same manner as in Example 1, except that 3 g of apatite hydroxide was used as a mixed solution of 18 g of MEK and 15 g of toluene as a diluting solution of the PU stock solution. The moisture permeability and antimicrobial properties of the prepared polyurethane composite films are measured and shown in Table 1.

Example 3

A polyurethane composite film was prepared in the same manner as in Example 1, except that 5 g of apatite hydroxide was used as a mixed solution of 18 g of MEK and 15 g of toluene as a diluting solution of the PU stock solution. The moisture permeability and antimicrobial properties of the prepared polyurethane composite films are measured and shown in Table 1.

Comparative Example 1

The composite film was prepared in the same manner as in Example 3, and the antimicrobial properties of the film that did not adsorb silver ions were measured and shown in Table 1.

Moisture permeability
(g / m ² ? 24h) Antimicrobiality (%) Escherichia coli Staphylococcus aureus Klebsiella pneumoniae Example 1 7,592 99.99 99.99 99.99 Example 2 8,032 99.99 99.99 99.99 Example 3 8,611 99.99 99.99 99.99 Comparative Example 1 8,611 90.5 94.6 97.2

Referring to Table 1, the films prepared in Examples 1 to 3 exhibited 99.9% or more of antimicrobial activity. However, the film of Comparative Example 1, which does not adsorb silver ions, can be used as antimicrobial fiber with antibacterial property of 99.9% or less. none.

Claims (3)

Putting a hydrophilic polyurethane resin into an organic solvent to prepare a polyurethane stock solution;
Preparing a nano hydroxide apatite dispersion having an average particle size of 100-200 nm by pulverizing with apatite hydroxide through ultrasonic treatment in an organic solvent;
Preparing a polyurethane / apatite composite composition by stirring the apatite hydroxide dispersion into the polyurethane stock solution;
Preparing a film-forming polyurethane composition in which water / organic solvent mixture is added to the composite composition to form polyurethane microbeads;
Manufacturing a polyurethane composite film by film casting the polyurethane composition; And
Method for producing a polyurethane composite film having excellent antimicrobial activity comprising the step of adsorbing silver ions by immersing the polyurethane composite film in a silver nitrate solution. The method according to claim 1,
The hydroxide apatite is a method for producing a polyurethane composite film excellent antimicrobial, characterized in that it contains 0.5 to 10% by weight relative to the total weight of the polyurethane composition. The method according to claim 1,
The water / organic solvent mixture is a method for producing a polyurethane composite film, characterized in that the mixing weight ratio of 9: 1 to 8: 2.

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