Paper coating material having environment-friendly, water-proof and oil-proof properties, and method of manufacturing the same
Provided are a paper coating material having environment-friendly, water-proof, and oil-proof properties, and a method of manufacturing the same. The paper coating material includes a copolymer emulsion in which a silicon-based polymer and an acryl-based polymer are copolymerized, the copolymer emulsion having the weight average molecular weight of 100,000 to 200,000, and a colloidal aqueous solution of gelatinized polyvinyl alcohol to be mixed with the copolymer emulsion. The environment-friendly paper coated with the environment-friendly coating material according to the present invention is excellent in water-proof, oil-proof and heat sealing properties, harmless to the human body when used for packaging food, and recyclable as a raw material for making paper. It is also biodegradable and therefore, environment-friendly.
1. A method of manufacturing a paper coating material, the method comprising:
(a) adding, to a reactor, water, acryl-based monomer, an initiator, an emulsifier, and a buffer;
(b) adding a silicon-based monomer to the reactor at a uniform rate;
(c) producing a copolymer emulsion having a weight average molecular weight of 100,000 to 200,000 by adjusting the temperature of the reactor;
(d) putting water and polyvinyl alcohol into a separate container and stir prepare a colloidal aqueous solution of gelatinized polyvinyl alcohol; and
(e) adding the colloidal aqueous solution of gelatinized polyvinyl alcohol to the copolymer emulsion.
2. The method of claim 1 , wherein the weight ratio between an acryl-based monomer and a silicon-based monomer, which form the copolymer emulsion, is 99:1 to 99.9:0.1.
3. The method of claim 2 , wherein the weight ratio between the copolymer emulsion and the colloidal aqueous solution of polyvinyl alcohol is 85:15 to 95:5 based on a solid content.
4. The method of claim 1 , wherein the colloidal aqueous solution of gelatinized polyvinyl alcohol is prepared by adding 7 to 15 wt % of polyvinyl alcohol into water and stirring for 1 to 10 minutes at a temperature of 85 to 98° C.
5. The method of claim 1 , wherein the glass transition temperature of the copolymer component of the copolymer emulsion is 300 to 340° C.
6. The method of claim 1 , wherein the degree of saponification of the polyvinyl alcohol is 92 to 99 mol %.
7. The method of claim 1 , wherein in step (a), the temperature of the reactor is maintained at 50 to 70° C., and in step (c), the temperature of the reactor is maintained at 70 to 90 ° C.
8. A paper coating material comprising:
a copolymer emulsion in which a silicon-based polymer having a repeating unit represented by formula 1 below and an acryl-based polymer having a repeating unit represented by formula 2 below are copolymerized, wherein particles included in the copolymer emulsion have a weight average molecular weight of 100,000 to 200,000; and
a colloidal aqueous solution of gelatinized polyvinyl alcohol mixed with the copolymer emulsion,
in formulae 1 and 2 above, R1 to R4 may be same or different, and are each independently hydrogen, or a substituted or unsubstituted alkyl group or aryl group.
9. The paper coating material of claim 8 , wherein the weight ratio between the acryl-based polymer and the silicon-based polymer is 99:1 to 99.9:0.1.
10. The paper coating material of claim 9 , wherein the weight ratio of the copolymer emulsion and the colloidal aqueous solution of polyvinyl alcohol is 85:15 to 95:5 based on a solid content.
11. The method of claim 1 , wherein the glass transition temperature of the copolymer component of the copolymer emulsion is 300 to 340° C.
12. The paper coating material of claim 8 , wherein the degree of saponification of the polyvinyl alcohol is 92 to 99 mol %.