Transparent gas barrier composite film and its preparation method

Patent metadata

Field	Value
Publication number	US-9701799-B2
Application number	US-201414508307-A
Country	US
Kind code	B2
Filing date	Oct 7, 2014
Priority date	Aug 18, 2014
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

The invention provides a transparent gas barrier composite film and its preparation method. The transparent gas barrier composite film is formed by having polyvinyl alcohol, graphene oxide and a crosslinking agent undergo blending, crosslinking, film casting and isothermal crystallization processes where a weight ratio of graphene oxide to polyvinyl alcohol is 0.1 wt %, graphene oxide induces crystallization of polyvinyl alcohol to form a hybrid structure compose of polyvinyl alcohol crystals, graphene oxide and the crosslinking agent, crystallinity of polyvinyl alcohol is more than 30%, transmittance of the composite film is more than 85%, and the oxygen transmission rate of the composite film is less than 0.005 cc/m 2 /day.

First claim

What is claimed is:

1. A method for preparing a transparent gas barrier composite film, comprising:
providing a polyvinyl alcohol containing aqueous solution;
providing a graphene oxide dispersed aqueous solution;
performing a blending procedure, to blend the polyvinyl alcohol containing aqueous solution with the graphene oxide dispersed aqueous solution to obtain a casting solution wherein a weight ratio of graphene oxide in the graphene oxide dispersed aqueous solution to polyvinyl alcohol in the polyvinyl alcohol containing aqueous solution is less than 0.1 wt %;
performing a cross-linking procedure for 1-6 hours, to add a cross-linking agent into the casting solution to have in-situ cross-linking reaction;
performing a film-casting procedure, to coat the casting solution after the in-situ cross-linking reaction on a substrate to form a coating and dry the coating so as to obtain a composite film which has a crosslinking content being about 1.0 wt. %; and
performing an isothermal crystallization procedure for 1-6hours at a specific temperature to have crystals of polyvinyl alcohol grow and to have graphene oxide induce the crystals of polyvinyl alcohol to grow so as to incorporate with graphene oxide and the cross-linking agent to form a hybrid network structure of the crystals of polyvinyl alcohol, graphene oxide and the cross-linking agent.

2. The method according to claim 1 , wherein, in the cross-linking procedure, the cross-linking agent is glutaraldehyde or sodium tetraborate.

3. The method according to claim 2 , wherein the cross-linking agent is glutaraldehyde and the cross-linking agent in the casting solution (being 100 wt %) is 0.2-0.85 wt %.

4. The method according to claim 2 , wherein the cross-linking agent is sodium tetraborate and the cross-linking agent in the casting solution (being 100 wt %) is 0.1-1.0wt %.

5. The method according to claim 1 , wherein the specific temperature is within 80-120° C.

6. The method according to claim 5 , wherein the specific temperature is within 90-100° C.

7. The method according to claim 1 , wherein, in the blending procedure, a weight ratio of graphene oxide to polyvinyl alcohol is 0.1 wt % and the obtained composite film has light transmittance larger than 85%.

8. The method according to claim 1 , wherein the substrate is polyethylene terephthalate and the coating after dried has a thickness of 10 μm.

9. The method according to claim 1 , wherein polyvinyl alcohol in the polyvinyl alcohol containing aqueous solution has concentration of 5-10 wt %.

10. A transparent gas barrier composite film, being formed by having polyvinyl alcohol, graphene oxide and a crosslinking agent undergo blending, crosslinking, film casting and isothermal crystallization procedures wherein a weight ratio of graphene oxide to polyvinyl alcohol is 0.1 wt %, graphene oxide induces crystallization of polyvinyl alcohol to form a hybrid structure compose of polyvinyl alcohol crystals, graphene oxide and the crosslinking agent, crystallinity of polyvinyl alcohol is more than 30%, and transmittance of the composite film is more than 85% and wherein said crosslinking content of the transparent gas barrier composite film is 1.0 wt. %.

11. The transparent gas barrier composite film according to claim 10 , wherein the cross-linking agent is sodium tetraborate; sodium tetraborate forms B—O—C bonds together with polyvinyl alcohol and graphene oxide; and a cross-linking rate defined as a ratio of numbers of B—O—C bonds to numbers of —CH 2 bonds is 1.05-1.15.

12. The transparent gas barrier composite film according to claim 10 , wherein the composite film has an oxygen transmission rate less than 0.005 cc/m 2 /day.

13. The transparent gas barrier composite film according to claim 10 , wherein the cross-linking agent is glutaraldehyde; glutaraldehyde forms C—O—C bonds together with polyvinyl alcohol and graphene oxide; and a cross-linking rate defined as a ratio of numbers of C—O—C bonds to numbers of —CH 2 bonds is 1.02-1.05.

14. The transparent gas barrier composite film according to claim 10 , wherein blending, crosslinking, film casting and isothermal crystallization procedures comprises the following steps:
providing a polyvinyl alcohol containing aqueous solution;
providing a graphene oxide dispersed aqueous solution;
performing a blending procedure, to blend the polyvinyl alcohol containing aqueous solution with the graphene oxide dispersed aqueous solution to obtain a casting solution wherein a weight ratio of graphene oxide in the graphene oxide dispersed aqueous solution to polyvinyl alcohol in the polyvinyl alcohol containing aqueous solution is less than 0.1 wt %;
performing a cross-linking procedure, to add a cross-linking agent into the casting solution to have in-situ cross-linking reaction; and
performing a film-casting procedure, to coat the casting solution after the in-situ cross-linking reaction on a substrate to form a coating and dry the coating so as to obtain a composite film.

Assignees

• Univ Chung Yuan Christian

Inventors

• Chen Jung-Tsai
• Hu Chien-Chieh
• Lee Kueir-Rarn
• Lai Juin-Yih
• Fu Ywu-Jang
• An quan-fu
• Lo Shen-Chuan
• Zhong Yue-Zhe

Classifications

• C08L2201/14

  Gas barrier composition · CPC title

• C08J5/18 Primary

  Manufacture of films or sheets · CPC title

• C08K3/0016

  Chemistry & Metallurgy · mapped topic

• C08K5/0025

  Crosslinking or vulcanising agents; including accelerators · CPC title

• B05D7/04

  to surfaces of films or sheets (producing layered products by applying coatings of pasty or pulverulent plastics B29C41/00) · CPC title