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
2000-04-27
2003-06-24
Cain, Edward J. (Department: 1714)
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
active
06583208
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a polyester resin composition comprising a polyester resin and a silane-treated foliated phyllosilicate, and to a process for preparing the same.
BACKGROUND ART
A polyester resin such as poly(ethylene terephthalate) has been used in a lot of industrial applications, for example, as a fiber and a film, since they are excellent in thermal resistance, chemical resistance, weatherability, mechanical properties, electrical properties and the like.
If a polyester resin composition can be prepared by dispersing a silicate, which is a silicon-containing compound having a layered structure, into the polyester resin in the form of a uniform layer, it is expected that mechanical properties and thermal resistance of the polyester resin can be improved without deterioration in surface appearance.
As a process for preparing such a resin composition using an organo-silane, following processes have been conventionally known. (1) A process for preparing a polymer nanocomposite, wherein monomers of a resin are polymerized in the presence of layered or fibrillar particles treated with an organometallic compound such as an organo-silane (the pamphlet of International Patent Publication No. 95/06090 (1995), the specification of U.S. Pat. No. 5,514,734).
(2) A process for preparing a polymer nanocomposite, wherein layered particles treated with an organo-silane or an onium salt and a melt kneadable resin are melt kneaded with a kneading machine such as a twin screw extruder (the pamphlet of International Patent Publication No. 93/04118 (1993), the pamphlet of International Patent Publication No. 93/11190 (1993)).
(3) A process for preparing a poly(arylene sulfide) composite material, comprising dissolving poly(arylene sulfide) in an organic solvent such as N-methyl-2-pyrrolidone, then dispersing a layered silicate treated with an organic onium salt, an organic halogenated silane or an organic silazane, and thereafter re-precipitating in a poor solvent such as water (Japanese Unexamined Patent Publication No. 194851/1993).
As a process for preparing the resin composition without using the organo-silane, following processes have been conventionally known.
(4) A process for preparing a thermoplastic polyester composition wherein a layered inorganic filler having an interlayer charge of 0.2 to 1.0 is swollen with glycols and thereafter a polyester resin is polymerized (Japanese Unexamined Patent Publication No.26123/1995).
(5) A process for preparing a thermoplastic polyester composition, wherein an inorganic compound such as swellable fluoromica obtained by heating a mixture of talc and alkali silicofluoride in a specific proportion is swollen with glycols and thereafter a polyester resin is polymerized (Japanese Unexamined Patent Publication Nos. 268188/1995 and 73710/1996).
In the above-mentioned (1) and (2) there is disclosed an invention relating to a resin composite material comprising a resin matrix and layered particles combined with an organometallic compound such as an organo-silane and, having an average layer thickness of at most about 50 Å and the maximum layer thickness of at most about 100 Å, namely, a composite material using layered particles combined with an organo-silane and nylon 6 as a resin matrix, for the purpose of improving resin's flexural modulus, flexural strength, deflection temperature under load and dimensional stability. But no resin composite material using a polyester resin as a resin matrix has been disclosed. If these processes apply to polyester resins, it is not sufficient to disperse the layered particles treated with silane and to improve mechanical properties and thermal resistance. When the process (3) is applied for a polyester resin, a mixed solvent of phenol and tetrachloroethane, hexafluoroisopropanol and the like can be mentioned as the organic solvent. From the viewpoints of safety and health, productivity, available poor solvents and the like, such a process is not industrially available at all and is extremely difficult to be applied as a process for preparing a polyester resin composition.
On the other hand, Japanese Unexamined Patent Publication No.118792/1997 points out that dispersing layered particles into molecules with separating them into individual layers in a polypropylene-based resin or in a vinyl-based polymer allows the layered particles to form a laminate structure, so that it becomes difficult for the layered particles to show isotropic properties (Science of Clay, Vol. 30 (2), 143-147 (1990)) and that when layered particles inherently having a high modulus of elasticity are dispersed into conditions similar to unit layers, they bend and the obtained modulus of elasticity is less than inherently expected.
The tensile modulus of elasticity of the composite material using layered particles combined with an organo-silane and nylon 6, which is disclosed in the above-mentioned (1) and (2) available from Allied-Signal Inc., has been improved in comparison with that of the nylon 6 resin itself. But it exhibits insufficient improvement compared to a composite material composed of layered particles treated with ammonium 11-decanoate and nylon 6.
Furthermore, the present inventors obtained a composite material by dispersing layered particles into a thermoplastic polyester resin in the form of a laminar structure similar to their unit layer (the thickness of the unit layer is about 10 Å) and evaluated its flexural modulus, flexural strength, deflection temperature under load and dimensional stability. It has been found that the effects are insufficient though they have been improved in comparison with materials in which such conventional particles are contained, in the form of laminated and flocculated states, in a thermoplastic polyester resin by means of an extrusion melt mixing or the like.
Moreover, the present inventors have attempted to prepare a thermoplastic polyester resin composition in accordance with the conventional methods using no organo-silane, namely, the methods of (4) and (5), but could not obtain desired dispersing state, layer thickness and physical properties. Namely, a small amount of a swellable fluoromica could not improve modulus of elasticity or deflection temperature at all, and it was found out that a layer thickness or a dispersing state of the swellable fluoromica in the composition are the same as those of the aggregated structure of the swellable fluoromica before mixing by transmission electron microscope observation and small-angle X-ray diffraction measurement.
As mentioned above, the present situation is that techniques in which a polyester resin composition having excellent physical properties is obtained by safely, completely, uniformly and finely dispersing inorganic substances into a thermoplastic polyester resin have not been provided yet.
Accordingly, even if a layered silicate is dispersed in a state similar to forming a unit layer, wherein the average layer thickness is at most about 50 Å and the maximum layer thickness is at most about 100 Å, or even if layered silicate is incorporated in a conventional state wherein it remains laminated or flocculated, it is difficult to obtain polyester resin compositions sufficiently improved in mechanical properties, deflection temperature under load and dimension stability.
DISCLOSURE OF THE INVENTION
The object of the present invention is to solve the above-mentioned conventional problems and to provide a polyester resin composition having improved flexural modulus of elasticity, flexural strength, deflection temperature under load and dimensional stability, which can give molded articles with excellent appearance and to provide a process for preparing the same by exfoliating inorganic compounds into laminars having suitable thickness which can exhibit an effect of improving physical properties and dispersing the inorganic compounds as many individual layers with thickness in nanomerter orders.
Namely, the present invention relates to
(1) a polyester resin composition comprising a
Armstrong Westerman & Hattori, LLP
Cain Edward J.
Kaneka Corporation
Lee K Wyrozebski
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