Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
1999-09-22
2003-05-13
Wu, David W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C528S175000, C528S179000
Reexamination Certificate
active
06562935
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to thermoplastic aromatic polysulfone resins. More precisely, it relates to thermoplastic aromatic polysulfone resins which have a reduced viscosity within a specific range and have a specific sum total of the number of phenolic hydroxyl groups and the number of metallic salts thereof per a repeating unit of the polymer.
DESCRIPTION OF RELATED ART
Aromatic polysulfone resins have been used as constitutive materials for various coating substances, adhesives and composite materials, since they are not only excellent in heat resistance, flame retardation, chemical resistance and so on but also good in adhesion to materials such as metals, glass, ceramics, various resins and carbon compounds. In a utilization of the resin, for example, an organic solvent solution of the resin is applied onto a substrate, which is then subjected to heat treatment to cause molecular weight-increase i.e., further polymerization, followed by inactivation.
Among the aromatic polysulfone resin, particularly those having a phenolic hydroxyl group are applied to such use. As such thermoplastic aromatic polysulfone resins, those having a reduced viscosity (RV) and the sum total of the number of phenolic hydroxyl groups and the number of metallic salts thereof contained in 100 repeating units of the polymer of 0.41 and 0.9 (JP-A-47-1087), 0.49 and 1.02 (JP-A-50-40700), 0.16 and 12 (JP-A-52-16535), and 0.53 and 1 (JP-A-59-191767), respectively, etc, have been known.
These thermoplastic aromatic polysulfone resins, however, had problems that they require severe conditions for heat treatment, i.e. a high treatment and a long period of heating, and that matters insoluble in an organic solvent are formed which cause rough surface and insufficient adherence of coating when the organic solvent solution of the resin is applied onto a substrate.
The present inventors have conducted extensive studies for solving these problems. As the result, they have found the fact that, when a thermoplastic aromatic polysulfone resin having a specific reduced viscosity and a specific sum total of the number of phenolic hydroxyl groups and the number of metallic salts thereof per a repeating unit of the polymer is used, the molecular weight-increase and the inactivation can be attained under moderate conditions and that the formation of the insoluble matters which cause various defects can be avoided. The present invention has been completed based upon such facts.
SUMMARY OF THE INVENTION
The present invention provides a practically superior thermoplastic aromatic polysulfone resin which has a reduced viscosity (RV) of 0.36 to 0.45 dl/g and a sum total A of the number of phenolic hydroxyl groups and the number of metallic salts thereof contained in 100 repeating units of the polymer of 1.6 or more.
The thermoplastic aromatic polysulfone resin according to the present invention has a reduced viscosity (RV) of 0.36 to 0.45 dl/g.
The reduced viscosity (RV) herein refers to a value obtained by measuring a solution of a resin having a concentration of 1.0 g/100 ml in N,N-dimethylformamide with Ostwald's viscosity meter at 25° C.
When the aromatic polysulfone resin has a reduced viscosity (RV) higher than 0.45 dl/g, a gel-like material insoluble in solvents and infusible even at a high temperature is formed. This can be a cause of defects in use as a coating material, an adhesive and a composite material. When it has a reduced viscosity less than 0.36 dl/g, the effect of molecular weight-increase by heat treatment decreases and the treatment requires a higher temperature and a longer time. A reduced viscosity of 0.38 to 0.45 dl/g is preferred because the effect of molecular weight-increase by heat treatment is enhanced.
The thermoplastic aromatic polysulfone resin of the present invention has a sum total A of the number of phenolic hydroxyl groups and the number of metallic salts thereof contained in 100 repeating units of the polymer of 1.6 or more.
When the sum total is less than 1.6, the effect of molecular weight-increase by heat treatment decreases and the treatment requires a higher temperature and a longer time. Considering the molecular weight-increase effect, it is desirable that the sum total A and the reduced viscosity (RV) satisfy the following formula:
0.45/(RV)
1.56
≦A≦0.74/(RV)
1.56
One repeating unit of the polymer in the aromatic polysulfone resin of the present invention has one —SO
2
— group.
Examples of the repeating unit include those represented by the following formula (1) or (2):
(—Ph—SO
2
—Ph—O—) (1)
(—Ph—SO
2
—Ph—O—A—O—) (2)
wherein Ph represents a para-phenylene group and A represents a group of the formula (3):
—Ph′—(—B—Ph′—)m— (3)
wherein Ph′ represents a phenylene group, B represents a direct bond, an alkylene group having 1 to 3 carbon atoms, an oxygen atom or a sulfur atom, and m represents an integer of 1 to 3.
The aromatic polysulfone resin of the present invention can be produced according to a known manner. For example, it can be produced by a condensation polymerization of a divalent phenol compound having a sulfone group and another divalent compound by using a catalyst, such as an alkali metal carbonate and an alkali metal hydrogen carbonate, in a high polar organic solvent. Examples of the divalent phenol compound having a sulfone group include dihydroxydiphenylsulfone. Examples of the other divalent compound include dihalogenobenzenoid.
When the dihalogenobenzenoid compound is used as the other divalent compound, the amount of the dihalogenobenzenoid compound is preferably within a range of 80 to 110% by mol based on the divalent phenol compound.
Examples of the highly polar organic solvent includes dimethylsulfoxide, 1-methyl-2-pyrrolidone, sulfolane(1,1-dioxothiolane), 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, diethylsulfone, diisopropylsulfone and diphenylsulfone.
The alkali metal carbonate and hydrogen carbonate is preferably sodium carbonate, potassium carbonate, and the corresponding hydrogen carbonates.
Generally, the alkali metal carbonate or hydrogen carbonate is used in an amount providing at least 0.95 equivalent of alkali metal atom per a phenol group and preferably an amount providing an excess of 0.001 to 0.25 equivalent of alkali metal atom per a phenol group.
The specific reduced viscosity (RV) of the aromatic polysulfone resin of the present invention, i.e. 0.36 to 0.45 dl/g, can be attained, for example, by adjusting the conditions of the condensation polymerization, such as polymerization temperature, polymerization time, the amount or kind of the catalyst to be used and the molar ratio of the divalent phenol compound having a sulfone group and the other divalent compound. Although the concrete conditions of the condensation polymerization to attain the specific reduced viscosity (RV) vary depending on the kind of monomers etc., the conditions can be easily determined, for example, by conducting a preliminary experiment.
The specific sum total A of the aromatic polysulfone resin of the present invention, i.e. 1.6 or more, can be attained, for example, by adjusting the conditions of the condensation polymerization, such as those mentioned above. Although the conditions of the condensation polymerization to attain the specific reduced viscosity (RV) vary depending on the kind of monomers etc., the conditions can be easily determined, for example, by conducting a preliminary experiment.
The specific reduced viscosity (RV) and the specific sum total A of the aromatic polysulfone resin of the present invention can also be attained by mixing two or more kinds of aromatic polysulfone resins which have reduced viscosities (RV) and sum totals A different from each other. In this case, the reduced viscosity of the aromatic polysulfone resins to be mixed should be 0.45 dl/g or less. Methods for mixing in this case are not particularly limited and include, for example, mixing of powders to another powders, mixing utilizing a solution and the like.
Th
Harlan R.
Sumitomo Chemical Company Limited
Wu David W.
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