White pigment comprising ZIF-based powder, polymer resin film and method for changing color of medium using white pigment

Abstract

The present invention provides a white pigment comprising a ZIF-based (zeolitic imidazolate framework) powder having a structure in which zinc (Zn) and an imidazole-based organic substance are bonded, a polymer resin film comprising the white pigment and a method for changing a color of a medium using the white pigment.

Claims

1. A method for producing a white pigment for inhalation through the respiratory organs comprising: dissolving zinc nitrate heptahydrate in ethanol and ammonia water to prepare a first solution, dissolving an imidazole-based organic substance in ethanol to prepare a second solution, mixing the first and second solutions, recovering a white pigment; and dispersing the white pigment in a polymer resin to prepare a polymer resin film; wherein the white pigment is suitable for inhalation through the respiratory organs and comprises a zeolitic imidazolate framework (ZIF)-based powder having a structure in which zinc (Zn) and the imidazole-based organic substance are bonded, wherein the ZIF-based powder is a compound in which zinc (Zn) and benzimidazole are bonded, and wherein the ZIF-based powder is contained in an amount of 80 to 100 wt % based on the total weight of the white pigment, and wherein the polymer resin film comprises 11 wt % to 30 wt % of the white pigment based on the total weight of the polymer resin film.

2. The method according to claim 1, wherein the ZIF-based powder comprises an organic-inorganic composite in which the zinc (Zn) and the nitrogen atom of the imidazole-based organic substance form a coordinate bond.

3. The method according to claim 1, wherein the polymer resin comprises one or more polymer resins selected from the group consisting of polyacrylonitrile, polypropylene, polyethylene, polyethylene terephthalate, polycarbonate, polymethyl methacrylate, poly(meth)acrylate, polyimide, polyamide, polyvinyl chloride, polyethylene oxide and polypropylene oxide.

4. The method according to claim 1, further comprising dispersing in a medium a pigment composition comprising the white pigment.

5. The method according to claim 4, wherein the pigment composition comprises the white pigment in a range of 0.5% to 99.5% by weight based on the total weight of the pigment composition.

6. The method according to claim 1, wherein the polymer resin is a plastic, a water-soluble gel, a paste, a paint, or a coating liquid.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a powder photograph of ZIF-8;

(2) FIG. 2 is a powder photograph of ZIF-8;

(3) FIG. 3 is a photograph immediately after ZIF-8 powder is put into a weak acid solution;

(4) FIG. 4 is a photograph after ZIF-8 powder is put into a weak acid solution and then sonication is performed using a sound wave of 20 kHz for 5 seconds;

(5) FIG. 5 is a photograph after ZIF-8 is put into a weak acid solution and sonication is performed for 5 seconds using a sound wave of 20 kHz;

(6) FIG. 6 is a photograph after Al.sub.2O.sub.3 is put into a weak acid solution and then sonication is performed for 10 minutes using a sound wave of 20 kHz;

(7) FIG. 7 is a photograph after TiO.sub.2 is put into a weak acid solution and then sonication is performed for 10 minutes using a sound wave of 20 kHz.

(8) FIG. 8 shows the polymer resin dispersion liquids and the polymer resin films obtained in Example 3 and Comparative Example 3, respectively.

DETAILED DESCRIPTION OF INVENTION

(9) Hereinafter, the present invention will be described with reference to examples according to the present invention, but this is for easier understanding of the present invention and the scope of the present invention is not limited by them.

EXAMPLES 1 TO 2 AND COMPARATIVE EXAMPLES 1 to 2

Preparation of White Pigment

Example 1

(10) 0.5 g of zinc nitrate heptahydrate was completely dissolved in 30 ml of ethanol, and 5 ml of ammonia water was added to this solution. In another container, 10 ml of ethanol and 0.3 g of benzimidazole were completely dissolved and then mixed with the above-prepared solution Immediately after mixing, a white emulsion was generated, and after stirring the generated emulsion for 10 minutes, a white solid phase ZIF-8 powder was obtained by using a centrifuge.

(11) A photograph of this ZIF-8 powder was shown in FIG. 1.

(12) Referring to FIG. 1, it was confirmed that the ZIF-8 was white in a solid powder state.

Example 2

(13) ZIF-8 powder was also synthesized by a method similar to that of Example 1 above.

(14) A photograph of this ZIF-8 powder was shown in FIG. 2.

(15) Referring to FIG. 2, it can be confirmed that the ZIF-8 is also white in the powder state.

Comparative Example 1

(16) Al.sub.2O.sub.3 powder was prepared.

Comparative Example 2

(17) TiO.sub.2 powder was prepared.

Experimental Examples 1 and 2

Experimental Example 1: Determination of Decomposition in a Weakly Acidic Aqueous Solution

(18) The ZIF-8 powder of Example 1, the ZIF-8 powder of Example 2, the Al.sub.2O.sub.3 powder of Comparative Example 1 and the TiO.sub.2 powder of Comparative Example 2 were each added by 0.5 g to a weak acid aqueous solution (pH: 6) to confirm the decomposition, and the results were shown in FIGS. 3 to 7.

(19) Referring to FIGS. 3 to 7, it can be seen that the Al.sub.2O.sub.3 powder of Comparative Example 1 and the TiO.sub.2 powder of Comparative Example 2 do not change, whereas the ZIF-based powders are completely decomposed and dissolved.

Experimental Example 2: Evaluation of Inhalation Toxicity

(20) For the ZIF-8 prepared in Example 1, an inhalation toxicity experiment was performed according to the OECD Guideline 436 (Acute Inhalation Toxicity—Acute Toxic Class Method). Three female and three male experimental rodents were placed in an inhalation chamber, a sample injection mask was connected to the nose of each subject, and then the ZIF-8 aerosol was generated using water as a medium and injected into the subject. The input concentration was set at 5 mg/L, and it was injected for 4 hours and the states of the subjects were observed for 14 hours, and it was confirmed that one of them died.

(21) As a result, it was confirmed that the ZIF-8 of Example 1 belonged to the non-hazardous substance group as an LC50 (50% lethal concentration when inhaled) of 5.2 mg/L.

Example 3 and Comparative Example 3: Production of Polymeric Resin Film

Example 3

(22) The ZIF-8 powder of Example 1 and a polyacrylonitrile resin were dispersed in dimethylformamide so as to be 2 wt % and 18 wt %, respectively, from which a polymer resin film was produced.

Comparative Example 3

(23) A polyacrylonitrile resin was dispersed in dimethylformamide so as to be 20 wt %, from which a polymer resin film was produced.

(24) As shown in FIG. 8, it was confirmed that the polymer resin film of Comparative Example 3 had a light yellow color, whereas the polymer resin dispersion of Example 3 had an opaque white color, and the finally provided polymer resin film also represented an opaque white color.