Hydrous gel and production process and use of the hydrous gel

Abstract

A hydrous gel substantially comprising at least two polymers selected from the group consisting of polyacrylic acid, sodium polyacrylate and partially neutralized polyacrylate, and water, the polymers being crosslinked by containing an aluminum compound, wherein the pH when the hydrous gel is 100-fold diluted with purified water is from 6.5 to 8.5. A hydrous gel which can stably hold an ascorbic acid or a derivative thereof, has high gel strength, exhibits good adhesion to an adherend and causes no liquid syneresis can be provided.

1 . A hydrous gel comprising a gel comprising at least two polymers selected from the group consisting of polyacrylic acid, sodium polyacrylate and partially neutralized polyacrylate crosslinked with an aluminum compound, and water, and an ascorbic acid or a derivative thereof, wherein the pH when said hydrous gel is 100-fold diluted with purified water is from 6.5 to 8.5.  
   
   
       2 . The hydrous gel as claimed in  claim 1 , wherein said pH is from 7.0 to 8.0.  
   
   
       3 . The hydrous gel as claimed in  claim 1  or  2 , wherein the aluminum compound is magnesium hydroxide-aluminum hydroxide co-precipitate.  
   
   
       4 . The hydrous gel as claimed in any one of  claims 1  to  3 , wherein the aluminum compound content is from 0.01 to 10 parts by mass per 100 parts by mass of said hydrous gel.  
   
   
       5 . The hydrous gel as claimed in any one of  claims 1  to  4 , wherein the content of the ascorbic acid or the derivative thereof is from 0.01 to 10 parts by mass per 100 parts by mass of said hydrous gel.  
   
   
       6 . The hydrous gel as claimed in any one of  claims 1  to  5 , wherein the ascorbic acid derivative is ascorbic acid-2-phosphoric ester or a salt thereof.  
   
   
       7 . The hydrous gel as claimed in any one of  claims 1  to  6 , wherein said hydrous gel comprises a polyhydric alcohol.  
   
   
       8 . The hydrous gel as claimed in any one of  claims 1  to  7 , wherein when said hydrous gel is formed into a film having a thickness of 0.5 mm and exposed to 25° C. and 60% at relative humidity for 24 hours and then the tackiness on the surface thereof is measured according to the Tack Test Method of JIS Z0237, the ball tack value at an inclined angle of 30° is 10 or more.  
   
   
       9 . A process for producing a hydrous gel, comprising preparing a mixture containing at least two polymers selected from the group consisting of polyacrylic acid, sodium polyacrylate and partially neutralized polyacrylate, an aluminum compound, water and an ascorbic acid or a derivative thereof, and heating said mixture at 25 to 65° C.  
   
   
       10 . The process for producing a hydrous gel as claimed in  claim 9 , wherein the pH when said hydrous gel is 100-fold diluted with purified water is adjusted to 6.5 to 8.5.  
   
   
       11 . The process for producing a hydrous gel as claimed in  claim 10 , wherein the pH is adjusted to 7.0 to 8.0.  
   
   
       12 . A cosmetic material comprising a hydrous gel claimed in any one of  claims 1  to  8 .  
   
   
       13 . A preparation for external application comprising a hydrous gel claimed in any one of  claims 1  to  8 .