Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Patent
1991-06-12
1993-09-07
Kight, III, John
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
528308, 5283082, 525437, 525444, C08G 6320, C08G 6378, C08J 1106
Patent
active
052430200
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a process for the production of high molecular weight polyester resin from polyester resin having a lower molecular weight.
Particularly, the invention relates to a process in which the polyester resin is blended in a molten state with an additive adapted to accelerate the achievement of high viscosity, transformed into a granulate and then treated in a solid state polycondensation reactor.
Such a process is known U.S. Pat. No. 4,147,738 in which the additive is an aromatic polycarbonate. In this known process the accelerating agent is blended with a branched copolyester.
From U.S. Pat. No. 4,132,707 is known to blend a branching component with poly (1,4-butylene terephthalate) (PBT) or with mixtures of polyethyleneterephthalate (PBT) and PBT in order to obtain branched copolyester having a suitably high melt viscosity.
The object of the present invention is to provide a new process with which it is possible to obtain a higher increase of the upgrading kinetic of the solid state polycondensation if compared with the kinetic of the known processes.
According to the invention, this object is achieved by blending the resin with a dianhydride of an aromatic tetracarboxylic acid.
The dianhydride is preferably selected from the group consisting of pyromellitic dianhydride, benzophenone dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) thioether diahydride, bisphenol A bisether dianhydride, 2,2-bis (3,4-dicarboxylphenyl) hexafluoropropane dianhydride, 2, 3, 6, 7-naphtalenetetracarboxylic acid dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1, 2, 5, 6-naphthalenetetracarboxylic acid dianhydride, 2,2', 3,3'-biphenyltetracarboxylic acid dianhydride, hydroquinone bisether dianhydride, bis (3,4-dicarboxyphenyl) sulfoxide dianhydride, 3, 4, 9, 10-perylene tetracarboxylic acid dianhydride and mixtures thereof.
The dianhydride is most preferably pyromellitic dianhydride, 3,3', 4,4' benzophenonetetrocarboxylic acid dianhydride and mixtures thereof.
Particularly preferred is the use of pyromellitic dianhydride (PMDA).
With the term "polyester resin" are also intended copolyester resin. The process is particularly advantageous for alkylene terephtalates and copoly (alkylene terephtalates) utilized for injection molding, blow molding, extrusion and which are useful in the production of yarn obtained by melt spinning.
The blending of polyester resin with dianhydride is preferably performed in a counter-rotating non-intermeshing vented twin screw extruder at a temperature between 200.degree. and 350.degree. C., depending from the melting point of the polymer or copolymer.
The use of such kind of extruder allows to perform a good distribution of dianhydride in the melt and to avoid problems of local high concentrations of dianhydride due to its high reactivity. The mixing effect of this kind of extruder approaches exponential performance and allows to use very short residence time in the extruder.
The process according to the invention is particularly indicated for the production of high viscosity PET or COPETs. The known processes have the drawback that the upgrading time (that is the residence time in the solid state polycondensation reactor), which is required by a given solid state temperature, is extremely long also with higher solid state temperatures. However, the use of higher temperatures such as 220.degree. C. is limited only for PET or COPETs which have a melt temperature .gtoreq.250.degree. C. The solid state treatment of COPETs with melting temperature below 250.degree. C. is only possible in the continuous polycondensation process using reaction temperature lower than 200.degree. C. This requires a residence time of the product in the solid state polycondensation reactor of 15-38 hours in order to obtain a final intrinsic viscosity of 0.8-1.1 dl/g starting from a resin having an intrinsic viscosity I.V. of about 0.6 dl/g. The use of h
REFERENCES:
patent: 3553157 (1971-01-01), Dijkstra
patent: 4132707 (1979-01-01), Borman
patent: 4436782 (1984-03-01), Ho
patent: 4680345 (1987-07-01), Kabayashi et al.
patent: 4772649 (1988-09-01), Andrews et al.
Culpeper Mullis Jeffrey
Kight III John
Phobos N.V.
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