Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Reexamination Certificate
2002-05-29
2004-06-15
Foelak, Morton (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
Reexamination Certificate
active
06750263
ABSTRACT:
TECHNICAL FIELD
This invention relates, in the production of a porous cross-linked polymer, preferably a porous cross-linked polymer having open cells formed continuously both on the surface and through the interior thereof, by the horizontal continuous polymerization of a water in oil type high internal phase emulsion (hereinafter occasionally abbreviated briefly as “HIPE”), to a technique concerning the mode, shape and structure, and material of a weir utilizing non-Newtonian and thixotropic viscosity of the HIPE for the sake of preventing the HIPE from leaking, enabling the formed polymer to acquire and retain a necessary thickness throughout to the opposite end parts, preventing the polymer from failing to cure owing to the decrease in an oxygen supply, and permitting the formed polymer to retain a superposed sheet such as an upper film.
This invention also relates to a novel method for the production of a porous cross-linked polymer, preferably a porous cross-linked polymer having open cells formed continuously both on the surface and through the interior thereof, by the horizontal continuous polymerization and curing in a polymerizing furnace of an HIPE using a supporting member on the lower side and a sheet material on the upper side and also to a technique for obtaining a porous cross-linked polymer as a cured product enjoying improved surface smoothness and excelling in accuracy of thickness.
Further, this invention relates to a technique for supplying an HIPE to an apparatus for the horizontal continuous polymerization, shaping the HIPE, and controlling the thickness of the formed HIPE for the sake of effecting the horizontal continuous polymerization of the HIPE with satisfactory accuracy of thickness and also to a novel method for producing by this technique a porous cross-linked polymer, preferably a porous cross-linked polymer having open cells formed continuously both on the surface and through the interior thereof.
The term “shaping” as used in the specification refers to an action of converting a shapeless mass into a mass of a prescribed shape; the term “controlling the thickness” refers to an action of converting a shapeless mass into a mass of a prescribed shape (i.e., shaping) and imparting a prescribed thickness to the mass of the prescribed shape; and the term “accuracy of thickness” refers to the deviation and error concerning the prescribed thickness.
BACKGROUND ART
Concerning the gasket for the production of a methyl methacrylate (occasionally referred to briefly as “MMA”) resin plate by the continuous cast polymerization of a polymerizing syrup centering on MMA, a Newtonian fluid having a low viscosity, U.S. Pat. No. 3,872,197, U.S. Pat. No. 3,988,098, JP-B-60-31,643, etc. have disclosed methods which, by means of gaskets adapted to be used as compressed, produce a plate having a thickness in the approximate range of 25 to 50% of the outer diameter of the relevant tube of the gasket. These methods, however, entail problems of failing to impart a desired thickness to the produced resin plate because the gasket in use is formed of a soft resin and is consequently susceptible of deformation caused by the clamping force or heat and a problem of increasing dispersion of the plate thickness. Concerning the gasket fit for the cast polymerization that involves the cell cast polymerization and the continuous cast polymerization, JP-A-5-253,951, JP-A-5-329,847, etc., while proposing the improvements in shape, structure, and material for the gasket of the kind as mentioned above, have disclosed methods for using gaskets similarly adapted to be used as compressed and producing a plate having a thickness in the approximate range of 30 to 90% of the outer diameter of the relevant tube of gasket. Incidentally, the cast polymerization has not been proposed for the use in the polymerization of an HIPE, a non-Newtonian, thixotropic and viscous fluid. Naturally, no proposal has ever been made as to the weir that includes a gasket for the use in the cast polymerization.
The methods for producing a porous cross-linked polymer by the polymerization of an HIPE have been disclosed, for example, in WO 97/27240, WO 97/37745, etc.
WO 97/27240 discloses as a method for the production of a porous cross-linked polymer by the polymerization of an HIPE using a film, a method for the combined continuous and batch polymerization which comprises continuously packing a vertical band-shaped zippered bag made of a resin film with an HIPE, reeling the packed bag, and then polymerizing the HIPE in the bag batchwise. Further, WO 97/37745 discloses a method for the production of a porous cross-linked polymer which comprises coating an HIPE on a porous substrate (such as a felt), causing at least part of the HIPE to impregnate the porous substrate, and polymerizing the HIPE deposited on the substrate.
The method for polymerizing an HIPE as disclosed in WO 97/27240, however, entails the problem of failing to make the most of the advantage of the continuous packing step because the operation from packing through polymerization of the HIPE cannot be carried out continuously and consequently because the transitional stage between the step for continuous packing of HIPE and the step for batch polymerization constitutes itself a rate-determining process. Further, since the operation from packing through polymerization of the HIPE is not carried out continuously, the film selected for the use in this method leaves out of consideration about durability at elevated temperatures and capability of recyclic use as well. This method also entails the problem of imposing limits on height (width) and thickness of the bag, encountering difficulty in retaining uniformity of thickness and performance quality of the bag, and failing to control the width and the thickness freely, because the lower part of the bag tends to gain in thickness under the weight of the HIPE and, to make the matter worse, because the oil phase and the liquid phase of the HIPE tend to deflect and separate vertically from each other, despite the belief that the lower part of the bag begins to thicken as compared with that at the time of packing the HIPE and the uniformity of thickness of the bag is exalted slightly in consequence of the reeling operation. This method, owing to the use of the bag made of film, further entails the problem of failing to obtain a porous cross-linked polymer which is possessed of varied properties on the opposite surfaces, though it barely obtains a porous cross-linked polymer possessed of identical properties both on the surfaces.
WO 97/37745 states that the polymerization may be performed batchwise or continuously, whichever may suit the occasion better. It has absolutely no typical proposal regarding a process for the continuous production of an HIPE using a porous substrate and a polar material in combination.
The films disclosed in the conventional techniques have respectively definite qualities as described above. No typical proposal of any sort has ever been made concerning the selection of a film which is excellent in durability (resistance to heat, resistance to the action of monomer, resistance to hydrolysis, and capability of recycling) fit for the polymerization at elevated temperatures and capable of controlling the surface properties of a porous cross-linked polymer (such as smoothness, ability to form open cell structure, and resistance to occurrence of pinholes and voids).
(1) Technique Concerning Coating
The coating technique exists which continuously applies a liquid substance on a supporting member being advanced as retained horizontally (such as a belt conveyor and a film advanced through a horizontally set path).
The term “coating” used herein is defined as “applying on a substrate a layer intended for coating, finishing, or protecting either or both of the opposite surfaces of the substrate” (Coating & Laminating: published by Kako Gijutsu Kenkyusho).
The industrial coating technique has been aimed mainly at forming a thin film on a substrate. The coating materials generally adopted for
Nogi Kozo
Sakamoto Katsuhiko
Sasabe Masazumi
Fish & Richardson P.C.
Foelak Morton
Nippon Shokubai Co. , Ltd.
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