Stable, homogeneous thermosetting, liquid resin compositions useful for treating the surface of felted mineral fiber-board panels which are bonded with a hydrophilic binder to reduce sag and method of making the same. Compositions of this invention comprise a copolymer blend of (1) from about 25% to about 55% by weight, of a melamine-formaldehyde copolymer and (2) from about 75% to about 45% by weight of a urea-formaldehyde copolymer. These compositions may be stabilized through the addition of from about 0.05% to about 0.5% by weight of an ammonium hydroxide-sodium hydroxide stabilizer solution. Resin compositions of this invention may be reduced with water and/or compounded with fillers and other materials or they may be used alone.
RELATED APPLICATIONS
The present application is a division of our application Ser. No. 282,939, filed Aug. 23, 1972, for Copolymer Blends and Method of Making Same, which is a continuation of our earlier application Serial No. 107,583, filed January 18, 1971, both now abandoned.
Curable amino resins are prepared from a system having two components, each of which remains storage stable for extended periods of time. The two components are drawn from separate storage vessels and combined in an in-line mixer immediately prior to the point of use. The system reduces mixing costs and provides greater control over changes in viscosity, precipitation and resin particle size occurring during the mixing process. The resins are used as adhesives (binders) for wood fiber, particles and chips, as well as for paper products and plywood materials.
For sag-resistant ceiling boards, a board has at least two coatings, one on the front face (coating A) of the board and at least one other coating (coating B) on the back face of the ceiling board. Both of these coatings must have an elastic modulus of at least about 400,000 psi to make the board rigid. In addition to this, coating B, on the back face of the board, must have a higher coefficient of humidity expansion than coating A of the front face.
A melamine-containing resin modified with a cyclic urea prepolymer comprising urea, formaldehyde and ammonia or a primary amine. The prepolymer-modified melamine-containing resin provides useful binders alone, or when combined or coreacted with other resins. Products prepared with the binder include wood composites such as particleboard and medium density fiberboard.
The preparation of phenol-formaldehyde and melamine-formaldehyde resin-based binders extended with a cyclic urea-formaldehyde prepolymer and to products prepared using the binders. More particularly, the invention relates to a cyclic urea prepolymer comprising urea, formaldehyde, and ammonia or a primary amine which, when added to a phenol-formaldehyde or melamine-formaldehyde based resin, results in a useful binder for the manufacturer numerous articles.
The preparation of phenol-formaldehyde and melamine-formaldehyde resin-based binders extended with a cyclic urea-formaldehyde prepolymer and to products prepared using the binders. More particularly, the invention relates to a cyclic urea prepolymer comprising urea, formaldehyde, and ammonia or a primary amine which, when added to a phenol-formaldehyde or melamine-formaldehyde based resin, results in a useful binder for the manufacturer numerous articles.
