Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Treating polymer containing material or treating a solid...
Reexamination Certificate
1999-08-02
2001-04-24
Troung, Duc (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Treating polymer containing material or treating a solid...
C528S225000, C528S491000, C528S495000, C528S497000, C528S503000
Reexamination Certificate
active
06222009
ABSTRACT:
FIELD OF THE INVENTION
The invention is directed to the formation of alkyl-aryl alcohol resins for use in inks. In particular, the invention is directed to a process of forming polymeric alkyl-aryl alcohol resins by reducing alkyl-aryl polymeric ketone, using aluminum isopropoxide as a catalyst at a temperature of about 20° to about 90° C. and at atmospheric pressure.
BACKGROUND
Alkyl-aryl alcohol resins are useful in a variety of inks and other coatings. When used in non-aqueous ballpoint pen inks, alkyl-aryl alcohol resins provide a highly viscous ink that typically performs well over a large temperature range, typically from below 0° C. to temperatures experienced in the tropics, and maintains a flow capacity that allows the immediate start of writing, while assuring smooth, continuous writing over the temperature range without skipping, running, spotting, or droplet formation at the pen tip, even under conditions of high temperature and humidity.
One prior art method commonly used to form an alkyl-aryl alcohol resin was to hydrogenate an alkyl-aryl ketone/formaldehyde resin, such as that disclosed in U.S. Pat. No. 4,731,434 to Dörffel et al.
Alkyl-aryl ketone/formaldehyde resins may be formed by mixing formaldehyde, acetophenone, and a strong base, such as KOH, in methanol at reflux. The only acidic proton in the solution, the a-hydrogen to the carbonyl, is removed by the base to form an enolate, which can attack electron-deficient sites, such as the carbonyl carbons of the formaldehyde and the acetophenone. As aldehydes are more susceptible to nucleophilic attack than ketones, the enolate preferentially attacks the carbonyl carbon of the formaldehyde, forming an alkoxide. The alkoxide extracts a hydrogen from the methanol solvent, regenerating the base, and forming 3-hydroxy-1-phenyl propan-1-one. Further extraction of &agr;-hydrogen by the base results in the elimination of the OH group, and the formation of a vinyl phenyl ketone, which is formed preferentially because of the stability of the conjugated double bonds. By maintaining the basic conditions at a temperature of greater than 25° C., the &agr;,&bgr;-unsaturated ketone polymerizes to form the desired polymeric alkyl-aryl ketone resin.
In the prior art, the polymeric alkyl-aryl ketone was typically converted to a polymeric alkyl-aryl alcohol resin by reducing the polymeric ketone resin under conditions of high pressure and temperature, typically about 300 bar at about 135° C. to about 220° C., in the presence of hydrogen gas, nickel, and a chromium activated copper catalyst. These conditions result in the transfer of one hydrogen to each carbonyl carbon and each carbonyl oxygen, giving the desired polymeric alkyl-aryl alcohol.
However, heavy metal catalysts are toxic, and cause handling and waste disposal problems. Moreover, the required high temperature and pressure conditions, as well as the use of hydrogen gas, are hazardous. Therefore, a need exists for a relatively low temperature and pressure process for forming polymeric alkyl-aryl alcohol resins that does not require heavy metals. The present invention provides such a process.
SUMMARY OF THE INVENTION
The present invention is directed to a process for producing a polymeric alkyl-aryl alcohol resin by reducing a polymeric alkyl-aryl ketone resin, and is also directed to the resins produced with the process of the invention. The process of the invention comprises forming a mixture of a polymeric alkyl-aryl ketone resin and a metal alkoxide reducing agent in a solvent, such as an alcohol, toluene, xylene, and mixtures thereof; refluxing the mixture to form a metal alkoxide intermediate and a ketone; removing the ketone from the mixture; and reacting the solvent with the metal alkoxide intermediate to form a polymeric alkyl-aryl alcohol. Useful alkyl-aryl resins include condensation products of aliphatic (acetone) or aromatic (acetophenone) ketones and aliphatic (formaldehyde) or aromatic (benzaldehyde) aldehydes. These resins include, but are not limited to, poly (vinyl methyl ketone) and poly (vinyl phenyl ketone) and mixtures thereof. Useful metal alkoxide reducing agents include, but are not limited to aluminum isopropoxide, aluminum tert-butoxide, lanthanide isopropoxide, zirconium isopropoxide, and mixtures thereof. With the appropriate choice of solvent and metal alkoxide reducing agent, such as isopropyl alcohol and aluminum isopropoxide or tert-butyl alcohol and aluminum tert-butoxide, the reducing agent may be regenerated as the polymeric alkyl-aryl alcohol is formed in the last step of the process.
The high temperature and pressure conditions required in prior art processes are avoided in the process of the invention, which is typically carried out at a reflux temperature of from about 20° C. to about 90° C. and atmospheric pressure. The endpoint of the reaction can be easily be determined by an absence of the production of ketone. Preferably, the presence or absence of the ketone is determined using a spectroscopic method known in the art, and is most preferably determined using Fourier Transform Infrared spectroscopy (“FTIR”).
Preferably, the process comprises forming a mixture of a polymeric alkyl-aryl ketone resin and an aluminum isopropoxide reducing agent in an isopropyl alcohol solvent; refluxing the mixture to form an aluminum alkoxide intermediate and acetone; removing the acetone from the mixture; and reacting the isopropyl alcohol solvent with the aluminum alkoxide intermediate to form a polymeric alkyl-aryl alcohol. Typically, from about 10 to about 200 parts by weight of aluminum isopropoxide per 100 parts by weight of polymeric alkyl-aryl ketone resin is mixed with the resin in about 400 to about 1500 parts by weight of the solvent, and the aluminum isopropoxide is regenerated in the process.
The invention is also directed to a process for making a non-aqueous ink and to inks formed with the process of the invention. The process comprises forming a polymeric alkyl-aryl alcohol, as described above, and blending the polymeric alkyl-aryl alcohol resin with at least one solvent, a novalac resin, a lubricant, such as a sesquloleate, and a pigment to form the ink. Useful solvents include, but are not limited to, glycols, glycol ethers, cyclic amides, alcohols, and mixtures thereof.
REFERENCES:
patent: 4731434 (1988-03-01), Dörffel
Gregorian et al., “Reduction of Polymeric Carbonyl Groups by Aluminum Isopropoxide,” Polymer Letters, 1964, pp. 481-482.
Kun et al., “Electron Exchange Polymers, XIV. Steric Hindrance in the Chemical Modification of High Polymers,” Journal of Polymer Science, 1960, vol. XLIV, pp. 383-389.
Bic Corporation
Pennie & Edmonds LLP
Troung Duc
LandOfFree
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