Claims
- 1. An adhesive comprising a resorcinol terminated urea-formaldehyde resin having the general formula: ##STR5## where .eta. = 0 to 10, said resin being cured under neutral or alkaline conditions by reacting it with a formaldehyde.
- 2. An adhesive as set forth in claim 1 wherein said resin is a sulfite-modified resorcinol terminated urea-formaldehyde.
- 3. An adhesive as set forth in claim 1 wherein said formaldehyde is paraformaldehyde.
- 4. In a method for forming an adhesive composition in which a compound of urea and formaldehyde is formed to a pH of about 8 and is polymerized to form a urea-formaldehyde resin under acid conditions of pH between about 3 and 4, the steps comprising:
- forming terminal methylol groups on the said resin under alkaline conditions, substituting terminal resorcinol groups for the hydroxyl radicals at a temperature of at most about 50.degree. C. and at a pH no greater than 4, and cross-linking the so-formed resorcinol-terminated urea-formaldehyde resin at a pH of at least 7.
- 5. The method of claim 4 in which the terminal resorcinol is added in a molar ratio to the originally employed urea of greater than 0.5 to 1.
- 6. The method of claim 4 in which the urea-formaldehyde resin is formed in a ratio of urea to formaldehyde of between about 1 to 2 and 1 to 1.
CROSS REFERENCE TO RELATED APPLICATIONS
This is a continuation-in-part of U.S. application Ser. No. 520,784, filed Nov. 4, 1974, which is a continuation of U.S. application Ser. No. 304,113, filed Nov. 6, 1972, both of which are now abandoned.
US Referenced Citations (8)
Foreign Referenced Citations (1)
Number |
Date |
Country |
1,102,394 |
Mar 1961 |
DT |
Non-Patent Literature Citations (1)
Entry |
Walker, J. Frederic, Formaldehyde (3rd Ed.) ACS Monograph Series No. 159, Reinhold Pub. Co. N.Y., 1964, pp. 382-384 & 637-638. |
Continuations (1)
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Number |
Date |
Country |
Parent |
304113 |
Nov 1972 |
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Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
520784 |
Nov 1974 |
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