Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From aldehyde or derivative thereof as reactant
Reexamination Certificate
1999-07-06
2002-06-04
Truong, Duc (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From aldehyde or derivative thereof as reactant
C528S097000, C528S101000, C568S717000, C568S731000, C568S734000, C568S744000
Reexamination Certificate
active
06399740
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to the formation of phenol aralkylation polymers and, more particulrly, to methods of preparing phenol aralkylation polymers with minimized formation of mono-functional and non-functional by-products.
DESCRIPTION OF RELATED ART
Recently, a new class of phenolic-type polymers have been developed by co-reaction among a phenolic monomer, at least one styrene derivative, and a divinyl aromatic monomer or aryl diolefin. In a first embodiment, these polymers can be prepared by initially aralkylating a phenolic monomer with the at least one styrene derivative to obtain aralkylated phenol, and thereafter reacting the aralkylated phenol with the aryl diolefin to obtain a phenol aralkylation polymer, having aralkylated phenols joined together with the aryl diolefin, generally with the primary linkage at the ortho position. The styrene monomer is added to a reaction medium containing the phenolic monomer and an acid catalyst, possibly in the presence of an inert solvent such as o-xylene. Phenol aralkylation polymers also can be prepared, in a second embodiment, by reacting phenolic monomer initially with aryl diolefin in the presence of acid catalyst to obtain a phenolvaryl diolelin polymer and then aralkylating the phenol/aryl diolefin polymer with at least one styrene derivative to obtain a phenol aralkylation polymer, generally with a portion of the phenolic linkages being para in orientation. In the case of polymers made using bisphenol-A as the phenolic monomer, the bisphenol-A generally is melted in the presence of an inert solvent before adding the diolefin monomer and catalyst.
Drawbacks associated with presently available methods for producing phenol aralkylation polymers are the level of formation of mono-functional degradation by-products of the phenolic monomer, particularly bisphenol A, by so-called “retro reactions,” as well as the level of non-functional by-products formed by homopolymerization of the styrene derivatives and/or the aryl diolefins. Formation of such by-products degrades functionality and reduces the yield of the desired phenol aralkylation polymer. It would be desirable to develop a process which avoids or substantially reduces homopolymerization and degradation by-product formation and improves functionality and yield of the desired phenol aralkylation polymer.
SUMMARY OF THE INVENTION
The present invention is directed to an improved method of preparing poly-functional phenol aralkylation polymers exhibiting improved oil solubility, and improved compatibility with oil and alkyd-based polymers, as well as with urethanes, epoxies and actylates. The present invention is particularly directed to a method for preparing phenol aralkylation polymers with minimized homopolymerization, e.g., formation of non-functional by-products, and with minimized formation of mono-functional degradation by-products.
Present methods of preparing aralkylation polymers produce considerable amounts of mono-fuctional and non-functional adducts of the phenol reactant, especially bisphenol A, as well as allowing homopolymerization of styrenic monomers and/or aryl olefins. For example, the reaction of bisphenol-A, p-t-butyl styrene, styrene, and divinyl benzene in the presence of 70 wt % methane sulfonic acid (0.0022 moles MSA per mole of bisphenol-A) produces a strong exothermic reaction in which inter alia phenol, isopropenyl phenol, (p-t-butyl styrene) phenol, (p-t-butyl styrene) isopropenyl phenol, and polystyrene degradation by-products and reaction adducts are observed.
Phenol aralkylation polymers can be formed by the reaction among a phenolic monomer, a styrenic monomer and an aryl diolefin in the presence of a catalyst. Preferably, the phenolic monomer iially is arlkyi with a first portion of at least one styrenic monomer to obtain an aralkylated phenol, and the aralkylated phenol then is reacted with an aryl diolefin to obtain a phenol aralkylation polymer. Optionally, (though preferably) the phenol aralkylation polymer is further aralkylated with a second portion of at least one styrenic monomer. The preliminar aralkylation reaction between the phenolic monomer and the first portion of the styrenic monomer is believed to direct the subsequent reaction of the partially aralkylated phenolic monomer with the aryl diolefin to the formation of coupled aralkylation products through a combination of resonance, inductive and steric effects.
Preferably, the initial aralkylation reaction of the present invention is initiated by forming a reaction medium or mixture of the styrenic monomer and the phenolic monomer; heating the mixture to a first temperature; and then slowly adding an acid catalyst to allow the reaction mixure to exotherm to a second elevated temperature. It has been discovered that by employing a specific catalyst concentration, reactant concentrations, reaction temperature, and reaction time, the formation of mono-functional and non-functional degradation by-products, as well as the undesired homopolymerization of monomers, can be substantially reduced. According to a preferred embodiment of the invention, bisphenol-A is employed as a phenolic monomer. When using bisphenol-A, about 2 moles of styrenic monomer are added per mole of bisphenol A. A preferred catalyst is methane sulfonic acid (MSA). Methane sulfonic acid is preferably added to the reaction mixture at a molar ratio of moles of catalyst to moles of bisphenol A of about 0.0005:1. The reaction temperature preferably does not exceed about 140° C. at any time during the reaction. Under these controlled reaction conditions, phenol aralkylation polymers can be produced with no more than 10 wt % (100,000 ppm) of either or both phenol degradation by-products and poly aryl-olefin homopolymers.
Aralkylated polymers made by the invention, particularly in large commercial scale batches, are expected to have a low polydispersity and a well-defined (i.e., controlled) functionality making them useful for reaction into other polymer systems to increase the strength/modulus of the resulting polymeric adducts. The method of the present invention is especially applicable to those phenolic monomers of a relatively high melting point such as bisphenol-A and bisphenol-F.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present invention as claimed.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is directed to a method for preparing phenol aralkylation polymers which exhibit good oil solubility and show a decreased tendency to darken over time. The phenol aralkylation polymers ofthe present invention have substantially reduced phenol and formaldehyde emissions, and have excellent adhesion and corrosion properties. Also, the products of the invention have high solubility in non-aromatic (Hazardous Air Pollutants (“HAP's”) free) solvents. The phenolic aralkylation polymers made by the method of the invention are also useful for incorporation with many other polymers which include, but are not limited to, alkyds, urethane, epoxy, and acrylate polymer systems. The increase in aromatic character obtained by the practice of the present invention result in an enhancement in the compatibility of the phenolic aralkylation polymer with the aforementioned polymer types, and also generally lead to an enhancement of physical properties, adhesion, and barrier property performance.
The term “polymer” used throughout the specification and claims is intended to embrace adducts having a wide range of molecular weights (including products often referred to as oligomers) made by reacting the various monomers used in practicing the present invention.
The phrase “commercial-sized quantities” and phrases of similar import are intended to embrace those conditions of scale where one generally encounters significnt non-uniformities in the processes of heat and mass transfer. For instance, when preparing batches of phenol aralkylation polymer of one thousand pou
Bir David J.
Elahi Syed A.
Hariharan Rajan
Hutchings David A.
Lucas, Jr. Edward
Georgia-Pacific Resins Inc.
Truong Duc
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