Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Patent
1998-12-21
2000-08-08
Acquah, Samuel A.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
528296, 528298, 528300, 528302, 528307, 528308, 5283086, 526 62, 526 65, 526 66, 526 67, 526 68, 526 70, C08G 6302, C08F 200
Patent
active
061003697
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method for a continuous production of a polyester by melt-polymerizing a raw material consisting of a dicarboxylic acid component composed of mainly an aromatic dicarboxylic acid and containing an alicyclic dicarboxylic acid or an aliphatic dicarboxylic acid, or their ester-forming derivatives with a diol component.
BACKGROUND ARTS
"Polyesters" represented by a polyethylene terephthalate, a polybutylene terephthalate or a polyethylene naphthalate, are widely used for various uses, since they have excellent physical and chemical properties. And as for the uses, the polyesters are widely used not only as fibers for clothings and industrial fibers such as a tire cord by utilizing their excellent mechanical characteristics such as a strength and a modulus of elasticity, heat resistant characteristics, etc., but also as a film processed as a plane and a molded engineering-plastic product processed three dimensionally.
In general, the polyesters used in such various uses, are produced by a direct polymerization method or an ester interchange method. Here, firstly, the former direct polymerization method is described. In this method, a polyester precursor is produced by performing a direct esterification reaction of a dicarboxylic acid component composed of mainly an aromatic dicarboxylic acid and containing an alicyclic dicarboxylic acid or an aliphatic dicarboxylic acid, or their ester-forming derivatives with a diol component. and then performing a polycondensation of the above polyester precursor under an atmospheric pressure or a reduced pressure. While, in the later ester interchange method, a lower alkyl ester of the acid component with the diol component are subject to the ester interchange reaction to form another polyester precursor, and then a polycondensation reaction of the precursor is performed under the atmospheric pressure or the reduced pressure.
As to the above polyester polymerizations, conventionally, a batch-wise method is largely used, but in order to produce the polyesters at a low cost and to take an advantage of a scale merit, a shift to a continuous process has been promoted, and merits for adopting the continuous process such as improvements in the yield and quality of the product, a uniform quality, an improvement in operational efficiency, a reduction in production cost, etc., are extremely high.
In general, most of the continuous production methods of the polyesters are conducted by using a process combining each plural esterification reactors or ester interchanging reactors with polycondensation reactors. For example, it is performed that a monomer or an oligomer is formed by charging raw materials into the ester interchange reactor or the esterification reactor, then the formed material is consecutively supplied into an initial polycondensation reactor for performing the reaction under a reduced pressure to produce a polymer having a low molecular weight, and further the polymer having a low molecular weight is supplied to a polycondensation reactor under a reduced pressure to obtain a polymer having a medium molecular weight and a polymer having a high molecular weight.
In this case, a diol component distilled out of the polycondensation reactor for the polyesters, is condensed in a tube type heat exchanger or a wet type condenser generally in view of an economical advantage, and then recovered and reused as a part of the raw materials. Further, there are a method of recovering the diol component without a distillation and a method of recovering after the distillation in the recovery/reuse methods.
Incidentally, in the case of the former method, since water and low boiling materials as byproducts are contained in a large amount in the diol component distilled out of the polycondensation reactors, by using the diol component without the distillation, there are problems such as an effect to the physical properties of the obtained polyester, an inhibition to the ester interchange reaction and/or polycondensation reaction by the
REFERENCES:
JP 63-1355421, A (Nippon Ester K.K.), Jun. 7, 1998 (Abstract).
JP 49-52891, A (Toray Industries, Inc.) May 22, 1974 (Abstract).
JP 50-2760, A (Toray Industries, Inc.), Jan. 13, 1975 (Abstract).
Kurihara Hideshi
Miyajima Kazumoto
Acquah Samuel A.
Teijin Limited
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