Production of glass fiber products

A method of preparing a bonded glass fiber product comprising the steps of:

• a. forming glass fibers from molten streams of glass;
• b. combining the glass fibers with a heat curable aqueous binder composition comprising
• 1. 60-95 percent by weight of a complex polymeric component formed from a reaction mixture consisting of phenol, formaldehyde, a modifier selected from the group consisting of starch and compounds which are degradation products of starch, and urea, wherein said polymeric component is produced by:
• a. charging a reactor with a mixture of formaldehyde and phenol in a mole ratio of formaldehyde/phenol of from 2.9-4.2/1;
• b. reacting the mixture in the presence of a condensing agent until it has a free formaldehyde content of from 7-15 percent of the total weight of formaldehyde, phenol and water;
• c. adding to the reactor the starch or starch decomposition product in an amount ranging from 5 to 50 percent of the phenol charged;
• and
• d. cooling the reactor contents;
• 2. 10-80 percent of urea, based upon the weight of the phenol originally charged to produce the polymeric component, with the proviso that at least 5 percent of urea, based upon the weight of the phenol originally charged to produce the polymeric component is dissolved in the polymeric component for at least fifteen minutes at a temperature of at least 90.degree.F.
• 3. 0.5-25 percent of a lubricant based upon the total weight of the complex polymeric component and any unreacted urea,
• 4. 0.1-1 percent of a silane, based on the total weight of the complex polymeric component and any unreacted urea,
• 5. 0.2-3.0 percent of an ammonium salt of a strong acid based on the total weight of the complex polymeric component and any unreacted urea,
• 6. water, to dilute the binder to a desired solids content of from 1-40 percent,
• c. consolidating the fibers and heat curable aqueous binder composition into a loosely packed mass on a foraminous conveyor;
• and
• d. curing the heat curable binder composition in situ on the glass fiber product.