Method of scavenging formaldehyde using a low mole ratio melamine-urea-formaldehyde resin
AssigneeGeorgia-Pacific Resins, Inc.
InventorsRobert A. Breyer, Bill R. Arndell, Semyon Stompel
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Abstract
A method of scavenging formaldehyde in formaldehyde-based resins using a low mole ratio melamine-urea-formaldehyde resin composition. In addition, a formaldehyde-based resin containing a storage-stable low mole ratio melamine-urea-formaldehyde resin composition as a formaldehyde scavenger.
Claims21
A method of scavenging formaldehyde in a formaldehyde-based resin comprising adding to the formaldehyde-based resin a formaldehyde scavenging amount of a low mole ratio melamine-urea-formaldehyde resin having a formaldehyde to urea and melamine ratio of between about 0.5 and 1.1 prepared by:
- (a) reacting an aqueous mixture of formaldehyde and urea at an F/U mole ratio of about 1.9 to 2.5 under an alkaline condition;
- (b) thereafter adding a sufficient amount of a mild acid to reduce the pH of said mixture to about 5.0 to 5.7 and further reacting the mixture;
- (c) neutralizing the mixture to a pH of between about 6.5 and 6.9;
- (d) adding additional formaldehyde to said mixture, and then adding melamine in an amount of about 2 to 10 wt % based on total mixture weight, to achieve a cumulative F/(U+M) mole ratio of about 1.9 to 2.6 and continuing the reaction at a pH of about 6.2 to 6.9;
- (e) adding additional melamine to said mixture to achieve a cumulative F/(U+M) mole ratio of about 1.7 to 2.4;
- (f) adjusting the pH to about 7.6 to 8.0;
- and
- (g) then adding sufficient urea to produce a final F/(U+M) mole ratio of about 0.5 to 1.1.
A method of reducing the emission of formaldehyde from products consolidated with a formaldehyde-based resin adhesive comprising adding to the resin prior to application to the boards an amount of a low mole ratio melamine-urea-formaldehyde resin, applying the resin to the boards, and curing the resin;
- wherein the low mole ratio melamine-urea-formaldehyde resin has a formaldehyde to urea and melamine ratio of between about 0.5 and 1.1 and is prepared by:
- (a) reacting an aqueous mixture of formaldehyde and urea at an F/U mole ratio of about 1.9 to 2.5 under an alkaline condition;
- (b) thereafter adding a sufficient amount of a mild acid to reduce the pH of said mixture to about 5.0 to 5.7 and further reacting the mixture;
- (c) neutralizing the mixture to a pH of between about 6.5 and 6.9;
- (d) adding additional formaldehyde to said mixture, and then adding melamine in an amount of about 2 to 10 wt % based on total mixture weight, to achieve a cumulative F/(U+M) mole ratio of about 1.9 to 2.6 and continuing the reaction at a pH of about 6.2 to 6.9;
- (e) adding additional melamine to said mixture to achieve a cumulative F/(U+M) mole ratio of about 1.7 to 2.4;
- (f) adjusting the pH to about 7.6 to 8.0;
- and
- (g) then adding sufficient urea to produce a final F/(U+M) mole ratio of about 0.5 to 1.1.
A formaldehyde-based resin containing a formaldehyde scavenging amount of a low mole ratio melamine-urea-formaldehyde resin having a formaldehyde to urea and melamine ratio of between about 0.5 and 1.1 prepared by:
- (a) reacting an aqueous mixture of formaldehyde and urea at an F/U mole ratio of about 1.9 to 2.5 under an alkaline condition;
- (b) thereafter adding a sufficient amount of a mild acid to reduce the pH of said mixture to about 5.0 to 5.7 and further reacting the mixture;
- (c) neutralizing the mixture to a pH of between about 6.5 and 6.9;
- (d) adding additional formaldehyde to said mixture, and then adding melamine in an amount of about 2 to 10 wt % based on total mixture weight, to achieve a cumulative F/(U+M) mole ratio of about 1.9 to 2.6 and continuing the reaction at a pH of about 6.2 to 6.9;
- (e) adding additional melamine to said mixture to achieve a cumulative F/(U+M) mole ratio of about 1.7 to 2.4;
- (f) adjusting the pH to about 7.6 to 8.0;
- and
- (g) then adding sufficient urea to produce a final F/(U+M) mole ratio of about 0.5 to 1.1.
Dependencies are inferred from the claim text.