Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Patent
1994-07-11
1997-03-04
Acquah, Samuel A.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
525480, 525485, 525506, 525534, 525538, 524 81, 524123, 524442, C08K 549, C08G 828
Patent
active
056079907
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a method for rendering phenol-formaldehyde resin flame-resistant and to products containing such a resin. Particularly, the present invention relates to the use of halogen-free phosphorus compounds for making phenol-formaldehyde resins integrally flame-resistant.
Phenolic resins are employed as raw materials or as auxiliary agents in the form of binders and impregnating agents for the manufacture of a great variety of products.
The preferred fields of application of such resins are in the bonding of derived timber products and the production of molding and coating compositions. Phenolic resins are furthermore employed as binders for the manufacture of inorganic or organic fiber reinforced materials utilized as abrasives or abrasive coatings or as materials for heat insulation and soundproofing. Moreover, applications in the manufacture of resin papers or woven fabrics and in the manufacture of foams of phenolic resins and other construction materials resistant to chemicals are to be mentioned.
The phenol-formaldehyde condensation resins are acid or base catalyzed resins and are employed in the form of precondensed products called "novolak" or "resol" resins. The preparation of said products is described in the chemical standard literature, see, e.g., Ullmann, Enzyklop adie der chemischen Industrie, 2nd edition, vol. 13, pages 453 to 478.
Many products made by using phenol-formaldehyde resins have to meet flammability standard values. For instance, molded parts for the manufacture of cars which are made of non-woven fabrics or masonite boards bonded with phenolic resins must satisfy the inflammability requirements according to DIN 54333 and DIN 75200 as well as US-FMVSS-302.
The requirements to be met by these molded parts and the other materials bonded with phenolic resins mentioned above have, however, steadily increased over the years. For example, hardboards, particle boards and vermiculite boards for special applications such as for structures for fairs should be made flame-resistant according to construction material class B 1. While the requirements for being categorized in construction material class B 1 may be met by means of additives which are conventional in the plastics industry, said additives show certain disadvantages.
Presently materials showing various chemical characteristics are employed for providing flame-retardance. The most important examples thereof are aluminum hydroxide, aluminum sulfate, ammonium phosphate and polyphosphate, melamine borate, antimony oxide, red phosphorus and several halogen compounds, said compounds being added to the products of phenolic resins as additives in an additional operation.
If aluminum hydroxide is to meet the requirements with respect to flame-retardance, it must be added to the phenolformaldehyde resin in a concentration of up to 50% by weight, resulting, however, in a substantial alteration of the physical properties of, e.g., hardboards.
Flame-proofing agents such as ammonium phosphate and sulfate are water-soluble and may thus be leached out of said materials and final products, respectively. Ammonium sulfate dissolved in molded parts based on woven fabrics may additionally cause corrosion.
The use of ammonium polyphosphate causes problems regarding its uniform distribution in the phenolic resin which in turn results in unsatisfactory materials bonded with phenolic resins. The required construction material class B 1 cannot be achieved with borates. Melamine borate may, however, be employed as partial component for preventing afterglowing.
The employment of halogen compounds and of antimony oxide is undesirable in environmental respect. Red phosphorus as flame-proofing agent leads to problems in the handling thereof.
From J. W. Lyons, "The Chemistry and Uses of Fire Retardants", 1970, pages 417-418, it is known to react phosphorus ester chlorides with phenolic bodies in order to make phenol-formaldehyde resins flame-resistant. Said reaction proceeds under elimination of HCl gas and is thus only applicable to novo
REFERENCES:
patent: 5162394 (1992-10-01), Trocino et al.
Dorn Karlheinz
Frankenfeld Klaus
N agerl Hans-Dieter
Sommer Klaus
Acquah Samuel A.
Chemische Fabrik Budenheim Rudolf A. Oetker
LandOfFree
Method for making phenol-formaldehyde resins flame-resistant does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for making phenol-formaldehyde resins flame-resistant, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for making phenol-formaldehyde resins flame-resistant will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2146483