ANTIMICROBIAL MATERIALS BASED ON POLYLACTIC ACID OLIGOMERS, PROCESS FOR PREPARING THE SAME, AND USE THEREOF

Abstract

This disclosure provides a biodegradable antimicrobial material based on polylactic acid oligomer represented by formula 1 as an active ingredient. The disclosure also provides a process for preparing the polylactic acid oligomer and an antimicrobial product prepared therefrom.

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Claims

1. An antimicrobial material comprising a polylactic acid oligomer as an active ingredient, wherein the polylactic acid oligomer is represented by formula 1, ##STR00004## n represents an integer of 1 to 28.

2. The antimicrobial material according to claim 1, wherein in formula 1, n represents an integer of 3 to 7.

3. The antimicrobial material according to claim 1, wherein the average molecular weight of the polylactic acid oligomer is 100 to 2000 g/mol.

4. The antimicrobial material according to claim 1, wherein the number average molecular weight of the polylactic acid oligomer is 200 to 600.

5. The antimicrobial material according to claim 1, wherein the antimicrobial material further comprises one or more additional antimicrobial active ingredients.

6. The antimicrobial material according to claim 1, wherein the antimicrobial material is against a microbe selected from the group consisting of bacteria and virus.

7. A process for preparing the polylactic acid oligomer according to claim 1, wherein lactic acid monomers are stirred and heated under nitrogen atmosphere, and reacted for 0.01 to 72 hours at a temperature of 100 to 300° C. and a pressure of 5 Pa to 5 MPa.

8. The process according to claim 7, wherein the temperature is 180 to 230° C.

9. The process according to claim 7, wherein the pressure is 1 kPa to 0.2 MPa.

10. The process according to claim 7, wherein the reaction is performed for 1 to 8 hrs.

11. An antimicrobial product prepared from the antimicrobial material according to claim 1.

12. The antimicrobial product according to claim 11, which is selected from the group consisting of an antimicrobial preparation, an antimicrobial fabric, a sanitary product, and a medical material.

Description

DESCRIPTION OF DRAWINGS

[0032] FIG. 1 is liquid chromatography-mass spectrometry of the polylactic acid oligomer with a degree of polymerization of 3˜7.

EMBODIMENTS

[0033] The following examples are for illustrative purposes only, and are not intended to limit the scope of protection of the present application.

Example 1

[0034] Adding 100 g of lactic acid to a reactor, under the protection of nitrogen, while stirring, the temperature was raised to 200° C. and maintained for 4 hours. The pressure in the reactor was maintained at one atmosphere. After the reaction, the temperature was lowered to room temperature, and all the reaction products were collected. A liquid chromatography-mass spectrogram was obtained by a mass spectrometer, as shown in FIG. 1. The degree of polymerization of the polylactic acid oligomer is about 4.

[0035] Property Testing

[0036] Diluting the polylactic acid oligomer obtained in Example 1 to 10 mg/mL or 20 mg/mL with phosphate buffer, and using the shaking method (referring to the national standard GB 15979-2002) to detect the antimicrobial activity, and PBS group as a blank control. The testing results are shown in Table 1.

TABLE-US-00001 TABLE 1 Antimicrobial performance of PLA oligomer Concentration of PLA oligomer Microbe 10 20 species Test standard Items mg/ml mg/ml S. aureus ASTM E2149 13a Antimicrobial >99.99 >99.99 (gram-positive reduction/% bacteria) Antimicrobial >4 >4 logarithm value Mv K. pneumoniae ASTM E2149 13a Antimicrobial >99.99 >99.99 (gram-negative reduction/% bacteria) Antimicrobial >4 >4 logarithm value Mv E. coli ASTM E2149 13a Antimicrobial >99.90 — (gram-negative reduction/% bacteria) Antimicrobial 3 — logarithm value Mv C. albicans ASTM E2149 13a Antimicrobial 84.00 96.68 (fungi) reduction/% Antimicrobial <1 >1 logarithm value Mv Methicillin- ASTM E2149 13a Antimicrobial 80.73 84.44 resistant reduction/% Staphylococcus Antimicrobial <1 <1 aureus logarithm (multi-drug value Mv resistant bacteria) Influenza A Technical standard Antimicrobial — >99.99 virus subtype for Disinfection reduction/% H1N1 (2002, Ministry of Antimicrobial — >4.00 Health P.R. China)- logarithm 2.1.1.10.6, value Mv 2.1.1.10.7. Influenza A Technical standard Antimicrobial — >99.99 virus subtype for Disinfection reduction/% H3N2 (2002 Ministry of Antimicrobial — >4.33 Health P.R. China)- logarithm 2.1.1.10.6, value Mv 2.1.1.10.7.

Antimicrobial Finishing of Polypropylene Nonwoven Fabric

[0037] Liquid PLA oligomer was mixed with solvent (PLA oligomer: H.sub.2O=1:10) to achieve homogenous solution, prior to be applied on the polypropylene nonwoven fabric through double-roll padding process. After evaporation of water by drying, the liquid PLA oligomer finished polypropylene nonwoven fabric was cooled down and collected in ambient condition for further antimicrobial test.

TABLE-US-00002 TABLE 2 Antimicrobial performance of PLA oligomer coated nonwoven polypropylene fabrics Ratio of PLA oligomer Testing Reduction mass to standard rate of fabric and microbes/ mass % method Tested Microbe Test time % * 9.0 ISO 18184: Influenza A virus 2 h >99.99 2019 subtype H3N2 9.0 ISO 18184: Influenza A virus 30 min >81.16 2019 subtype H3N2 9.0 ISO 18184: Influenza A virus 10 min >54.38 2019 subtype H3N2 9.0 ISO 18184: Influenza A virus 5 min >42.72 2019 subtype H3N2 13.0 ISO 18184: Influenza A virus 2 h >99.99 2019 subtype H3N2 9.0 ISO 18184: Influenza A virus 2 h >95.11 2019 subtype H1N1 9.0 ASTM S. aureus 1 h >99.99 E2149W, 2020 9.0 ASTM E2149 K. pneumoniae 1 h >99.99 20 9.0 ASTM E2149 C. albicans 24 h 81.7% 20 * Difference between microbes in samples before and after the disinfectant action divided by microbes in samples before the disinfectant action. Reduction rate = (A-B)/A. A is microbes in samples before the disinfectant action. B is microbes in samples after the disinfectant action.

[0038] It can be seen from Tables 1 and 2 that the polylactic acid oligomer has excellent antimicrobial activity against microbes including bacteria and virus. Therefore, the degradable oligomer of the present application has extremely high application potential in preparing antimicrobial materials (especially medical antimicrobial materials) and antimicrobial product.