Liquid-crystal emulsion oil in water type and a preparation method of the liquid-crystal emulsion

1. A liquid-crystal emulsion oil in water type, wherein it comprises of:

a) a continuous phase (aqueous phase) containing water, ethyl alcohol, acetone, polyvinyl alcohol, dispersing agent and boric acid,

b) a disperse phase (oil phase) containing the mixture of the thermotropic liquid crystals.

2. The liquid-crystal emulsion according to claim 1 , wherein it comprises the continuous phase containing polyvinyl alcohol in amount from 5 to 20% by weight.

3. The liquid-crystal emulsion according to claim 1 , wherein it comprises the continuous phase containing dispersing agent in amount from 1 to 2% by weight.

4. The liquid-crystal emulsion according to claim 1 , wherein it comprises the continuous phase containing boric acid in amount from 0.1% to 1.0% by weight.

5. The liquid-crystal emulsion according to claim 1 , wherein it comprises 14 to 48% by weight (on a dry matter basis) of the thermotropic liquid crystals mixture and 50 to 86% by weight (on a dry matter basis) of polyvinyl alcohol.

6. The liquid-crystal emulsion according to claim 1 , wherein it comprises polyvinyl alcohol of a molecular weight from 50000 to 130000 and hydrolysis degree of 83 to 98 molar %.

7. The liquid-crystal emulsion according to claim 1 , wherein it comprises the mixture of the thermotropic liquid crystals selected from the group consisting cholesteryl pelargonate, cholesteryl oleyl carbonate, cholesteryl propionate, cholesteryl chloride and 4,4′-dipentylazoxybenzene.

8. The liquid-crystal emulsion according to claim 1 , wherein it comprises nonoxynol-5 as the dispersing agent.

9. The liquid-crystal emulsion according to claim 1 , wherein the drop size of the oil phase (liquid-crystal phase) is lesser than 5 μm.

10. The liquid-crystal emulsion according to claim 1 , wherein the drop size of the oil phase (liquid-crystal phase) is lesser than 4 μm.

11. The liquid-crystal emulsion according to claim 1 , wherein the drop size of the oil phase (liquid-crystal phase) is from 1 to 2 μm.

12. The liquid-crystal emulsion according to claim 1 , wherein the emulsion viscosity is lesser than 5000 mPa·s.

13. The liquid-crystal emulsion according to claim 1 , wherein the emulsion viscosity is lesser than 4500 mPa·s.

14. The liquid-crystal emulsion according to claim 1 , wherein the emulsion viscosity is from 4000 to 4500 mPa·s.

15. A method for preparing liquid-crystal emulsion, wherein it comprises steps of:

a) preparation of oil phase by mixing the thermotropic liquid crystals;

b) preparation of aqueous phase by adding polyvinyl alcohol to the aqueous-alcoholic solution containing dissolved boric acid, and mixing and heating the mixture until polyvinyl alcohol is completely dissolved, then obtained solution is cooled down, acetone and emulsifying agent is added and the whole is mixed to obtain homogenous mass, after cooling to the room temperature the obtained mass is passed through the sieve of a number 29T, and it is transferred to the hermetically closed containers and placed in a room at the temperature not lower than 20° C. for 10 to 60 days;

c) the mixture of the thermotropic liquid crystals is vigorously poured into the aqueous phase and the whole is mixed using the stirrer with a rotation speed from 500 to 5000 l/min for 1 to 15 minutes to obtain the liquid-crystal emulsion.

16. The method according to claim 15 , wherein in step b) the mixture is heated to a temperature of about 80 to 85° C.

17. The method according to claim 15 , wherein in step b) obtained solution is cooled down to a temperature of 40° C.

18. The method according to claim 15 , wherein step c) the mixture of the thermotropic liquid crystals is poured into the aqueous phase at the temperature about 60 to 65° C.

19. The method according to claim 15 , wherein the aqueous phase is conditioned for 10 to 15 days before it is used in the emulsification process.

20. The method according to claim 15 , wherein the aqueous phase is conditioned for 15 to 30 days before it is used in the emulsification process.

21. The method according to claim 15 , wherein the aqueous phase is conditioned for 30 to 60 days before it is used in the emulsification process.

22. The method according to claim 15 , wherein for stirring of the aqueous phase and the oil phase, a slow-rotating stirrer is used.