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...
Patent
1998-03-20
2000-11-28
Szekely, Peter A.
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...
423610, 524413, 524847, 528279, 528425, C08K 322, C08L 3108
Patent
active
061536792
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to titanium oxide and a process for production thereof and also to a thermoplastic resin composition containing said titanium oxide.
BACKGROUND ART
Polyester consisting mainly of repeating units of ethylene terephthalate finds use as fiber, film, moldings, etc. in a variety of industrial fields because of its outstanding moldability and physical properties. It is often incorporated with titanium oxide to impart whiteness, opacity, lubricity, etc. The resulting polyester resin composition, however, poses a problem with frequent filament breakage or film breakage during processing or with film defects leading to uneven printing and surface irregularities.
Among several ideas proposed so far to address this problem is Japanese Patent Publication No. 265948/1988 which discloses a polyester composition containing highly dispersible titanium oxide characterized by its specific average particle diameter and water content as well as its surface treatment with an aluminum compound and/or silicon compound. Unfortunately, the surface treatment contributes only a little to improvement in the filament and film producing processes for its added cost, because it has no effect on coarse particles originally present in titanium oxide.
DISCLOSURE OF THE INVENTION
The present inventors carried out extensive studies to radically reduce coarse particles originally present in titanium oxide by noting how titanium oxide is dispersed in the resin composition. The studies led to the present invention which covers:
1. Titanium oxide characterized by its property that it disperses into ethylene glycol (as a dispersing medium) to give a 13 wt % suspension which has a specific resistance higher than 7000 .OMEGA..multidot.cm and passes through a filter paper with a pore size of 6 .mu.m such that the filtration pressure does not exceed 100 kPa after filtration for 4 minutes at a flow rate of 1.73 cm.sup.3 /min.multidot.cm.sup.2.
2. A thermoplastic resin composition which comprises a thermoplastic resin and the titanium oxide defined above.
3. A thermoplastic resin composition which comprises a polyester resin and the titanium oxide defined above.
4. A polyester resin composition which is composed of a polyester resin and titanium oxide and is characterized by its property that it passes through a filtration pressure tester under the following conditions such that the rise in filtration pressure after filtration for 1 hour satisfies the equation (I) below. %) of titanium oxide in the composition, provided that 0.3.ltoreq.C .ltoreq.15.
5. A process for producing a polyester resin composition composed of a polyester resin and titanium oxide, said process comprising adding a suspension in ethylene glycol of the titanium oxide defined in (1) above in the course of polymerization for polyester resin.
6. A process for producing a polyester resin composition composed of a polyester resin and titanium oxide, said process comprising incorporating, by using a mixer, the titanium oxide defined in (1) above into a polyester resin after the polymerization for the polyester resin is substantially complete.
7. A process for producing titanium oxide which comprises the steps of dispersing raw titanium oxide into a liquid, clearing the resulting titanium oxide dispersion of coarse titanium oxide particles, freeing the titanium oxide dispersion of liquid by drying, and causing the titanium oxide obtained in the previous step to impinge upon an object by the aid of a gas stream.
8. A process as defined in (7) above which gives rise to titanium oxide characterized by its property that it disperses into ethylene glycol (as a dispersing medium) to give a 13 wt % suspension which has a specific resistance higher than 7000 .OMEGA..multidot.cm and passes through a filter paper with a pore size of 6 .mu.m such that the filtration pressure does not exceed 100 kPa after filtration for 4 minutes at a flow rate of 1.73 cm.sup.3 /min.multidot.cm.sup.2.
BRIEF DESCRIPTIONS OF THE FIGURES
FIG. 1 is a schematic secti
REFERENCES:
patent: 3663499 (1972-05-01), Brinkmann
patent: 4388425 (1983-06-01), Strehler et al.
Asakura Ryosuke
Kawaji Tomio
Taniguchi Tomohiro
Miller Austin R.
Szekely Peter A.
Toray Industries Inc.
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