Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Reexamination Certificate
2000-10-20
2001-10-16
Acquah, Samuel A. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
C528S176000, C528S271000, C528S272000, C528S300000, C528S308000, C528S403000, C528S405000
Reexamination Certificate
active
06303745
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a polyester which has a high polarity and a high refractive index and which is useful as a material for producing fibers or plastics; to a process for producing the polyester; and to an intermediate for producing the polyester.
BACKGROUND ART
Examples of materials and products prepared from polyesters include polyester fiber such as Tetron, alkyd resin for preparing mechanical parts, and unsaturated polyester resin. These polyesters are widely employed in such applications as general-purpose fiber materials, elastic fiber materials, high-strength fiber materials, and plastics.
However, there is a demand for the development of a polyester that exhibits enhanced properties. One example is swimwear. When white swimwear fabricated with conventional Tetron is worn, the body of the wearer can be seen through the swimwear due to the proximity of the refractive index of water and that of Tetron. Meanwhile, swimwear fabricated with a conventional high-refractive-index polyester is disadvantaged by feeling uncomfortable against the skin and by having an unsatisfactory appearance. Thus, there is a demand for a polyester that can provide a fiber satisfying both a high refractive index and having a good sensation against the skin. In addition, conventional polyester has poor biodegradability, and thus a polyester having improved biodegradability is demanded.
In view of the foregoing, an object of the present invention is to provide a polyester having functions such as a high refractive index, high strength, and biodegradability.
DISCLOSURE OF THE INVENTION
In order to overcome the aforementioned drawbacks, the present inventors have conducted extensive studies on dicarboxylic acids which can serve as raw materials for producing polyesters, and have found that polyesters which are produced by polycondensing 2H-pyran-2-one-4,6- dicarboxylic acid and a variety of diols exhibit high mechanical strength and have a high refractive index and polarity and that a 2H-pyran-2-one ring has excellent biodegradability. The present invention has been accomplished on the basis of these findings.
Accordingly, the present invention provides a polyester having a structural repeating unit represented by formula (1):
(wherein R
1
represents a divalent hydrocarbon residue optionally having in the structure a heteroatom having no active hydrogen), and a process for producing the same.
The present invention further provides 2H-pyran-2-one-4,6-dicarboxylic acid esters represented by formula (2):
(wherein R
2
represents a C1-C24 divalent hydrocarbon residue). Among the monomers for producing the polyester of the present invention, the above carboxylic acid esters are novel compounds.
BEST MODES FOR CARRYING OUT THE INVENTION
R
1
in the structural repeating unit represented by formula (1) for constituting the polyester of the present invention represents a divalent hydrocarbon residue optionally having in the structure a heteroatom having no active hydrogen. Among divalent hydrocarbon residues, preferred are R
2
, R
2
—(OR
2
)
1
—, and R
2
—OCO—R
2
(wherein R
2
is a C1-C24 divalent hydrocarbon residue and 1 is a number between 1 and 4. Examples of preferred R
2
include a C1-C24 linear chain or branched chain alkylene group, a C3-C8 cycloalkane divalent residue, a C5-C10aromatic hydrocarbon divalent residue, a C7-C24 aralkyl divalent residue, and a C8-C24 alkylarylalkyl divalent residue. Examples of more preferred R
2
include an ethylene group, a trimethylene group, a propylene group, a tetramethylene group, a hexamethylene group, an octamethylene group, a decamethylene group, a dodecamethylene group, a phenylene group, a tolylene group, a xylylene group, a naphthalene group, a cyclohexylene group, and —CH
2
CH
2
(OCH
2
CH
2
)
2
—. These hydrocarbon residues may have a substituent having no active hydrogen such as an alkoxy (preferably C1-C6) group, an alkanoyl (preferably C2-C6) group, an alkyl (preferably C1-C6) group, an aryl (preferably C6-C14) group, or an aralkyl (preferably C7-C18) group.
The polyester of the present invention may further contain another structural repeating unit such as —(OCO—R
3
—COO—R
1
)—so long as the polyester contains a structural repeating unit represented by the aforementioned formula (1). Such a polyester is represented by formula (3) as described below:
(wherein R
3
represents a divalent hydrocarbon residue optionally having in the structure a heteroatom having no active hydrogen; m and n are integers; and R
1
is the same as defined above).
The polyester which is represented by formula (3) and has two types of structural repeating units may be a block copolymer or a random copolymer.
No particular limitation is imposed on the molecular weight of the polyester of the present invention, and it varies in accordance with use. Typically, the molecular weight based on the number average molecular weight is preferably 10,000-200,000, more preferably 20,000-150,000. The molecular weight is particularly preferably 40,000-100,000 in view of readiness in preparation of a melt thereof, mold ability from the melt, and development of physical properties such as mechanical strength of molded products.
The polyester of the present invention may be produced according to any one of Reaction schemes 1 to 3:
(wherein X
1
represents an alkoxy group or a halogen atom; and R
1
is the same as defined above).
Specifically, a 2H-pyran-2-one-4,6-dicarboxylic acid derivative (4) and a diol (HO—R
1
—OH) or an alkali metal compound thereof are subjected to polycondensation reaction, to thereby produce the polyester of the present invention (1).
Among dicarboxylic monomers (4), a monomer in which X
1
is an alkoxy group and a monomer in which X
1
is a halogen atom are novel compounds. The compounds can be produced by converting 2H-pyran-2-one-4,6-dicarboxylic acid represented by formula (4) (wherein X is OH) to an ester or an acid halide thereof through a customary method. Among alkoxy groups for X
1
, a lower alkoxy group is preferred, with a C1-C6 alkoxy group being particularly preferred in view of reactivity to diols. Among halogen atoms, a chlorine atom and a bromine atom are preferred.
Appropriate types of polycondensation may be employed in accordance with dicarboxylic species (4). For example, alcohol-removing-polycondensation is preferably employed when a dicarboxylic derivative (4) in which X
1
is an alkoxyl group is used and polycondensation is preferably employed when a dicarboxylic derivative (4) in which X
2
is a halogen atom is used.
In alcohol-removing-polycondensation, for example, a dicarboxylic acid dietser (4) and a diol are mixed at a mol ratio of approximately 1:1, and the mixture is heated.
In polycondensation, for example, a dicarboxylic acid halide (4) and a diol or an alkali metal compound thereof are mixed at a mol ratio of approximately 1:1, and the mixture is heated in an appropriate mixture. Examples of preferred alkali metal compounds include sodium dialcolate.
When the aforementioned polycondensation is carried out by use of HOCOR
3
COOH or a reactive derivative thereof in addition to HO—R
1
—OH, the following copolymer represented by formula (3) can be obtained.
Specifically, a 2H-pyran-2-one-4,6-dicarboxylic acid ester represented by formula (5) is homo-polycondensed while removing ethylene glycol to thereby produce a polyester having a structural repeating unit represented by formula (6).
In the reaction, for example, a compound (5) is reacted in the absence of a solvent but in the presence of calcium carbonate and diantimony trioxide, each inorganic compound being added in an amount of 1/10-1/100, preferably 1/20-1/80, more preferably 1/40-1/60 parts by weight. During the initial period in which ethylene glycol generates vigorously, the temperature of polycondensation is regulated to approximately 180° C. When generation of ethylene glycol becomes weak, homo-polycondensation is carried out at approximately 240C:
(wherein R
2
is the same as defined above).
Specifically, a diester represented by formula (2) an
Hotta Yasushi
Katayama Yoshihiro
Nishikawa Seiji
Shigehara Kiyotaka
Acquah Samuel A.
Cosmo Research Institute
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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