Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
1998-07-06
2001-01-23
Acquah, Samuel A. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C528S298000, C528S361000, C524S449000, C524S451000
Reexamination Certificate
active
06177500
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an aromatic polyester composition comprising an aromatic polyester containing a specific structural unit, and an inorganic filler. More particularly, the present invention relates to an liquid crystalline polyester composition having excellent balance between heat resistance and mechanical strength.
DESCRIPTION OF THE RELATED ART
Aromatic polyester compositions are known as engineering plastics having heat resistance. Recently, demands thereof are increasing for use in electronics parts.
It is known that aromatic polyesters can be obtained, for example, by poly-condensation of aromatic hydroxycarboxylic acids (X), aromatic diols (Y) and aromatic dicarboxylic acids (Z)as described in JP-A-54-77691 and JP-B-57-24407.
An aromatic polyester containing a p-oxybenzoyl unit (A) and a 4′-oxybiphenyl-4-carbonyl unit (B) is described in Macromolecules, 24, 4990(1991), H. R. Kricheldorf et al. However, there is scarce reference to mechanical properties thereof.
An aromatic polyester composition having higher heat resistance and mechanical properties is increasingly required with the increases of demands thereof.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an aromatic polyester composition having excellent balance between heat resistance and mechanical strength.
The present inventors have intensively studied on improvement in quality of such an aromatic polyester composition, and have found that the object can be attained by an aromatic polyester composition comprising a specific structural unit.
The present invention provides an aromatic polyester composition comprising 100 parts by weight of an aromatic polyester (&agr;) containing a p-oxybenzoyl unit (A) represented by the following formula (I):
and a 4′-oxybiphenyl-4-carbonyl unit (B) represented by the following formula (II):
and 1 to 400 parts by weight of an inorganic filler (&bgr;).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The ratio of p-oxybenzoyl unit (A)/4′-oxybiphenyl-4-carbonyl unit (B) in Aromatic polyester (&agr;) is preferably 10 to 90/90 to 10% by mole, more preferably 20 to 80/80 to 20% by mole, and further more preferably 60 to 80/40 to 20% by mole, for exhibiting heat resistance and mechanical strength.
Aromatic polyester (&agr;) contains the p-oxybenzoyl unit (A) and 4′-oxybiphenyl-4-carbonyl unit (B). Aromatic polyester (&agr;) may further contain an oxycarbonyl unit (C) represented by the general formula (III):
—O—Ar
1
—CO— (III)
wherein Ar
1
represents a divalent aromatic group which may be optionally substituted by a halogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group, the biphenyl unit represented by the formula (II) being excluded;
a dioxy unit (D) represented by the general formula (IV):
—O—Ar
2
—O— (IV)
wherein Ar
2
represents a divalent aromatic group which may be optionally substituted by a halogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group; or
a dicarbonyl unit (E) represented by the general formula (V):
—CO—Ar
3
—CO— (V)
wherein Ar
3
represents a divalent aromatic group which may be optionally substituted by a halogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group;
within the range which is not harmful to the effect of the present invention.
The oxycarbonyl unit (C) include aromatic oxycarbonyl units and aliphatic oxycarbonyl units. Specific examples of aromatic oxycarbonyl units include oxybenzoyls such as m-oxybenzoyl, 3-chloro-4-oxybenzoyl and 2-methyl-4-oxybenzoyl, oxynaphthoyls such as 2-oxy-6-naphthoyl and 1-oxy-5-naphthoyl, and oxybiphenylcarboxylic acids such as 3′-oxybiphenyl-3-carbonyl and 2,6-dimethyl-4′-oxybiphenyl-4-carbonyl. Specific examples of aliphatic oxycarbonyl units include oxybutanoyl and oxypentanoyl.
The dioxy unit (D) include aromatic dioxy units and aliphatic dioxy units. Specific examples of the aromatic dioxy units include dioxybenzenes such as p-dioxybenzene, m-dioxybenzene and 3-methyl-1,4-dioxybenzene, dioxynaphthalenes such as 2,6-dioxynaphthalene and 1,5-dioxynaphthalene, and dioxybiphenyls such as 4,4′-dioxybiphenyl and 3,3′-dioxybiphenyl. Specific examples of the aliphatic dioxy units include 1,2-dioxyethane, 1,2-dioxypropane, 2,2-dimethyl-1,3-dioxypropane, 1,4-dioxybutane and 1,6-dioxycyclohexane.
The dicarbonyl unit (E) include aromatic dicarbonyl units and aliphatic dicarbonyl units. Specific examples of the aromatic dicarbonyl units include dicarbonylbenzenes such as terephthaloyl, isophthaloyl and methylterephthaloyl, dicarbonylnaphthalenes such as 2,6-naphthalenedicarbonyl and 1,5-naphthaenedicarbonyl, and dicarbonylbiphenyls such as 4,4′-dicarbonylbiphenyl and 3,3′-dicarbonylbiphenyl. Specific examples of aliphatic dicarbonyl units include dicarbonylethane and dicarbonylbutane.
The method for producing the aromatic polyester (&agr;) used in the present invention is not particularly restricted. The aromatic polyester (&agr;) can be produced, for example, by a polycondensation reaction of the corresponding lower aliphatic carboxylate of a hydroxycarboxylic acid, such as a polycondensation reaction of p-acetoxybenzoic acid and 4′-acetoxybiphenyl-4-carboxylic acid; or a polycondensation reaction of the corresponding phenylester of a hydroxycarboxylic acid, such as a polycondensation reaction of phenyl p-hydroxybenzoate and phenyl 4′-acetoxybiphenyl-4-carboxylate.
The above-mentioned polycondensation reactions are conducted in the substantial absence of a solvent, in the presence or absence of a polymerization catalyst such as sodium acetate and antimony trioxide, usually at a temperature of 250 to 380° C., in the presence of an inert gas such as nitrogen, under normal pressure , reduced pressure or combination thereof, with removing by-produced lower aliphatic carboxylic acid or phenol out of the system.
The resulting aromatic polyester may be used without any treatment. Alternatively, the resulted aromatic polyester can be subjected to solid phase polymerization in order to remove unreacted raw materials or to improve physical properties. The solid phase polymerization is preferably conducted according to a method in which the resulted aromatic polyester is mechanically pulverized and the pulverized material, still in solid phase condition, is treated at 250 to 350° C. in an atmosphere of an inert gas such as nitrogen or under reduced pressure for 1 to 20 hours. It is preferable to select the treatment temperature and temperature-raising speed in the solid phase polymerization so that aromatic polyester particles are not fused to bond each other.
The aromatic polyester (&agr;) used in the present invention preferably has a flow beginning temperature of 250 to 400° C., more preferably 270 to 370° C. When the flow beginning temperature is too low, the heat resistance of a molded article lowers. When the flow beginning temperature is too high, molding becomes difficult. The flow beginning temperature herein referred to is a temperature at which a melt viscosity of 48000 poise is exhibited when a capillary type rheometer equipped with a die having an internal diameter of 1 mm and a length of 10 mm is used and a heat-melted material is extruded through a nozzle at a temperature-raising rate of 4° C./minute under a load of 100 kg/cm
2
.
Specific examples of the inorganic filler (&bgr;), which is another essential component used in the present invention, include glass fiber, glass bead, hollow glass sphere, glass powder, mica, talc, clay, silica, alumina, potassium titanate, wollastonite, calcium carbonate (heavy, light, glutinous), magnesium carbonate, basic magnesium carbonate, sodium sulfate, calcium sulfate, barium sulfate, calcium bisulfate, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, calcium silicate, siliceous sand, quartz, titanium oxide, zinc oxide, iron oxide graphite, molybdenum, asbestos, silica alumina fiber, alumina fiber, gypsum fiber, carbon fiber, carbon black, white carbon, d
Okamoto Satoshi
Yoshida Yoshifumi
Acquah Samuel A.
Birch & Stewart Kolasch & Birch, LLP
Sumitomo Cemical Company, Limited
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