Process for the production of polyhydroxy lignin-cellulose silicate polymer

The process for the production of foamed polyurethane silicate products by the following steps:

• (a) mixing and reacting the following components, thereby producing a polyhydroxy lignin-cellulose polymer;
• (i) a broken-down alkali metal plant silicate polymer produced by heating a mixture of 3 parts by weight of a cellulose-containing plant and 1 to 2 parts by weight of an oxidated silicon compound with 3 to 5 parts by weight of a melted alkali metal hydroxide to between 150.degree. C. and 220.degree. C. while agitating for 5 to 60 minutes;
• in an amount of 100 parts by weight;
• (ii) an epoxide compound, in an amount of 1 to 3 parts by weight;
• (iii) a Lewis acid, in an amount wherein the pH of the mixture of components (i), (ii) and (iii) is 5 to 6:
• (b) mixing and reacting 100 parts by weight of the polyhydroxy lignin-cellulose silicate polymer as produced in step (a), 1 to 600 parts by weight of a compound containing at least two isocyanate groups up to 50% by weight of an inert blowing agent, percentage based on the weight of the reaction mixture.