Stable liquid melamine urea formaldehyde resins, hardeners, adhesive compositions, and methods for making same
AssigneeCytec Technology Corp.
InventorsHuide Dennis Zhu, William Jacobs III, Robert G. Lees, Luis Mendonca, Roger C. Rasch
Life of this patent
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Abstract
The invention relates to a process for preparing a liquid melamine urea formaldehyde resin that has long term stability. The invention also relates to a liquid MUF resin with a high formaldehyde and melamine content. The invention further relates to a liquid suspension hardener including a catalyst, a thickener, a filler, and water. The invention also relates to a adhesive composition for use in wood bonding that is made by adding a hardener to the resin.
Claims24
A method of preparing a stable melamine urea formaldehyde resin, comprising:
- providing a first aqueous solution of formaldehyde;
- heating the solution;
- adding in a single step about 0.35 to 0.65 molar equivalents of urea based on the amount of formaldehyde provided in the first aqueous solution to form a UF mixture;
- adding acid to the UF mixture to adjust the pH to a value of about 4 to 7 to provide an acidified UF mixture;
- monitoring the viscosity of the acidified UF mixture until it reaches a value of about 150 cps to 1000 cps;
- adjusting the pH of the acidified UF mixture to a value of about 8 to 10 to provide a basic UF mixture;
- adding a second aqueous solution comprising about 0.24 to 1.27 molar equivalents of formaldehyde based on the amount of formaldehyde provided in the first aqueous solution to the basic UF mixture;
- adjusting the pH of the basic UF mixture to a value of about 8 to 10;
- adding in a single step about 0.15 to 0.55 molar equivalents of melamine based on the amount of formaldehyde provided in the first aqueous solution to the basic UF mixture to form an MUF mixture;
- monitoring the viscosity of the MUF mixture until it reaches a value of about 150 to 1000 cps;
- and
- adjusting the pH of the MUF mixture to a value of about 9 to 10 to provide the melamine urea formaldehyde resin having a viscosity that is less than about 1500 cps for at least about 14 days.
A liquid resin comprising formaldehyde, melamine, and urea, wherein the molar ratio of formaldehyde to melamine and urea is about 1.5:1 to 2.5:1, the molar ratio of melamine to urea is about 0.25:1 to 1.5:1, and the resin has a viscosity of less than about 1500 cps for about 14 days.
A liquid hardener, comprising a catalyst, a filler, a thickener, and water, wherein the filler remains suspended in the hardener for at least about 14 days.
An adhesive composition comprising a hardener and a melamine urea formaldehyde resin, the resin having a formaldehyde to melamine and urea molar ratio of about 1.5:1 to 2.5:1, a melamine to urea molar ratio of about 0.24:1 to 1.27:1, and a viscosity of less than about 1500 cps for at least about 14 days.
Dependencies are inferred from the claim text.