WO1998007779A9 - Compositions thermoplastiques comportant de l'oxyde de zinc et des homo ou copolymeres de tetrafluoroethylene et articles façonnes a partir de celles-ci - Google Patents

Compositions thermoplastiques comportant de l'oxyde de zinc et des homo ou copolymeres de tetrafluoroethylene et articles façonnes a partir de celles-ci

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Publication number
WO1998007779A9
WO1998007779A9 PCT/US1997/014510 US9714510W WO9807779A9 WO 1998007779 A9 WO1998007779 A9 WO 1998007779A9 US 9714510 W US9714510 W US 9714510W WO 9807779 A9 WO9807779 A9 WO 9807779A9
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WO
WIPO (PCT)
Prior art keywords
composition
zinc oxide
iii
polymer
weight percent
Prior art date
Application number
PCT/US1997/014510
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English (en)
Other versions
WO1998007779A1 (fr
Filing date
Publication date
Application filed filed Critical
Priority to CA002263323A priority Critical patent/CA2263323A1/fr
Priority to JP51087098A priority patent/JP2001524992A/ja
Priority to EP97937306A priority patent/EP0918816A1/fr
Priority to AU39849/97A priority patent/AU3984997A/en
Publication of WO1998007779A1 publication Critical patent/WO1998007779A1/fr
Publication of WO1998007779A9 publication Critical patent/WO1998007779A9/fr

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Definitions

  • thermoplastic polymers alone and blends of such polymers with other polymers such as polyimides, and polyimide precursor resins are injection moldable and provide a unique combination of properties.
  • the outstanding performance characteristics of these polymers under stress have made them useful in the form of bushings, seals, compressor vanes and impellers, pistons and piston rings, gears, thread guides, cams, brake linings, and clutch faces.
  • the present invention solves the aforementioned problems by providing a polymeric composition having uniformly dispersed therein controlled amounts of zinc oxide and non-fibrillating tetrafluoroethylene homopolymers and copolymers of tetrafluoroethylene, collectively referred to herein as PTFE, in finely divided form.
  • the zinc oxide must be of a selected particle size, and the PTFE must have a controlled molecular weight.
  • the two ingredients are present in the composition in a selected weight ratio. When used in accordance with the present invention, these additives disperse uniformly throughout the polymer matrix and give molding compositions of exceptional uniformity. Shaped articles prepared therefrom exhibit improved wear properties.
  • Polymeric blends of this invention comprise from about 40 to 98 weight percent of at least one thermoplastic polymer which is melt processible at temperatures of less than about 400°C, from about 1 to 38 weight percent of zinc oxide having a mean particle size of less than 3.7 ⁇ m, preferably at least 25% having a particle size of less than 2 ⁇ , and from about 38 to 1 weight percent of PTFE in finely divided powder form having a molecular weight in the range from about 80,000 to 1,000,000.
  • the PTFE has a mean particle size of from about 1.8 ⁇ m to about 150 ⁇ m. Preferably the size is from 4to 20 ⁇ m.
  • the zinc oxide and PTFE particles are present in a ratio of from about 95 parts PTFE/5 parts of zinc oxide to about 10 parts PTFE/90 parts zinc oxide.
  • compositions of this invention may also be comprised of blends of the thermoplastic polymers with other polymers such as polyimides and polyimide precursor resins. These blends may contain from about 40 to 93weight percent of thermoplastic polymer and from about 5 to 40 weight percent of a polyimide or polyimide precursor resin, preferably 10-30 weight percent of the polyimide or polyimide precursor resin is used.
  • the polyimide may or may not be melt processible.
  • FIG. 1 is a photomicrograph of a polymeric composition which is outside to scope of the present invention and is described in Sample VI of Example 3 showing poor dispersion of PTFE in the sample.
  • FIG. 2 is a photomicrograph of a polymeric composition of this invention
  • melt processible polymers can be blended with the zinc oxide and PTFE particles.
  • Polyamides which can be used include nylon 6, nylon 6,6, nylon 610
  • the melt processible polyesters are preferably in the form of liquid crystalline polymers (LCPs).
  • LCPs are generally polyesters including, but not limited to polyesteramides and polyesterimides.
  • LCPs are described in Jackson et al. in U.S. Pat. Nos. 4,169,933, 4,242,496, and 4,238,600, as well as in "Liquid Crystal Polymers: VI Liquid Crystalline Polyesters of Substituted Hydroquinones", Contemporary Topics in Polymer Science, 1984, Vol. 5, pp. 177-208. Others are described in Calundann, U.S. Pat. No. 4,219,461.
  • LCPs are prepared from monomers such as phenyl hydroquinone, hydroquinone, t-butyl hydroquinone, 1 ,4-benzene dicarboxylic acid, 1,3-benzene dicarboxylic acid, 4-hydroxybenzoic acid, terephthalic acid and 2,6-napthalene dicarboxylic acid in varying ratios.
  • Preferred LCP compositions are disclosed in U.S. Pat. Nos. 4,664,972 and 5,1 10, 896 which is incorporated by reference herein.
  • compositions of the first-mentioned patent consist essentially of (I) an aromatic diol consisting essentially of 95 to 55 mole % t- butylhydroquinone and 5 to 45 mole % of one or more polyaromatic diols, (II) a dicarboxylic acid component selected from "para” or “meta” oriented aromatic dicarboxylic or 1 ,4-cyclohexane dicarboxylic acid or mixtures thereof, provided that no more than 80 mole % of the dicarboxylic acid component comprises a naphthalene dicarboxylic acid, and (III) an aromatic hydroxycarboxylic acid component selected from 4-(4"-hydroxyphenyl)benzoic acid or mixtures thereof; where said copolyester contains equal chemical equivalents of components (I) and (II) and contain about 20 to 60 mole %, based on total moles (I)+(II)+ (III) of component (III).
  • compositions of the second mentioned patent consist essentially of recurring units derived from (I) hydroquinone, (II) 4,4'- dihydroxyphenyl, (III) terephthalic acid, (IV) 2,6-naphthalene dicarboxylic acid, and (V) 4— hydroxybenzoic acid wherein the mole ratio of (I): (II) is from 65:35 to 40:60, preferably 60:40 to 40:60, wherein the molar ratio of (III) to (IV) is from 85: 15 to 50:50, preferably 85: 15 to 60:40, wherein the molar ratio of (I) to (II) to the total of (III) to (IV) is substantially 1 : 1 , preferably 0.95-1.05 : 1.00, and wherein there are 200 to 600, preferably 200 to 450 moles of (V) per 100 moles of (I) plus (II).
  • LCPs useful in this invention consist essentially of repeating units derived from (I) t-butylhydroquinone and terephthalic acid, ( II) t- butylhydroquinone and 2,6-naphthalene carboxylic acid, and (III) 4- hydroxybenzoic acid, the molar ration of (I):(II) being about 4: 1 to about 1 :4, more preferably about 3: 1 to 1 :3 with the molar ratio of (I)+(II):(III) being about 3: 1 to about 2:3.
  • Aromatic polyimides such as those described in Edwards, U.S. Pat. No. 3,179,614, and Manwiller and Anton, U.S. Pat. No. 4,755,555, can be used.
  • polyimides have been found to be particularly satisfactory in the present invention, namely, those having a rigid polymeric structure.
  • rigid polymeric materials are those prepared using aromatic diamines and anhydrides such as m-phenylene diamine (MPD); bis- 4,4'(3 aminophenoxy)biphenyl; 3,4-oxydianiline (3,4-ODA); oxydianiline (ODA); p-phenylene diamine (PPD); benzophenone-3,3',4,4'-tetracarboxylic dianhydride (BTDA); bis phenol-A-diphthalicanhydride (BPADA); pyromellitic dianhydride (PMDA); and 3,3'4,4'-biphenyltetracarbocyclic dianhydride (BPDA).
  • MPD m-phenylene diamine
  • BPADA bis- 4,4'(3 aminophenoxy)biphenyl
  • 3,4-ODA 3,4-oxydianiline
  • ODA p-
  • the dianhydride and the aromatic diamine may be reacted in substantially equimolar quantities. However, excesses of dianhydride or diamine can be used to beneficially modify the properties of the final polyimide.
  • the reaction product of the dianhydride and the aromatic diamine is a polyimide precursor resin, containing polyamic acid which can be thermally or chemically converted to polyimide according to known techniques. Recently, Kaku, in U.S. Pat. No. 5,346,969, described blends of polyimide precursor resin such as described in Endrey, U.S. Pat. No. 3,179,631 and Gall, U.S. Pat. No. 3,249,588, with at least one polyamide or polyester, preferably in the form of liquid crystalline polymer (LCP).
  • LCP liquid crystalline polymer
  • Blends of polyimide precursor with at least one polymer which is melt processible at a temperature of less than about 400°C. are combined to provide polyimides with injection molding capability. At least one polymer which is melt processible at temperatures of less than about 400°C. is blended with the polyimide resin. Melt processible is used in its conventional sense, that the polymer can be processed in extrusion apparatus at the indicated temperatures without substantial degradation of the polymer.
  • the zinc oxide and PTFE particles are included in the blending operation.
  • the zinc oxide particles may be prepared from commercially available crystalline zinc oxide by grinding and screening the oxide to obtain the required particle size distribution.
  • Nonfibrillating tetrafluoroethylene polymers and copolymers such as tetrafluoroethylene/hexafluoropropylene are commercially available in micropowder form. E.I.du Pont de Nemours and Company sells such materials under its trademark, Teflon® MP. Preparation of such copolymers is described in Morgan, U.S. 4,879,362. Such copolymers have recurring units of tetrafluoroethylene and a comonomer selcted from the group consisting of hexafluoroproplyene, perfluoro(alkyl vinyl ether) where the alkyl group has 1-4 carbons and mixtures of the comonomers.
  • the present polymeric compositions may include additives in addition to zinc oxide and PTFE, such as molybdenum disulfide, glass fibers, carbon fibers and carbonaceous fillers such as graphite.
  • additives in addition to zinc oxide and PTFE such as molybdenum disulfide, glass fibers, carbon fibers and carbonaceous fillers such as graphite.
  • the particular additive selected will depend on the effect desired.
  • Suitable materials include coupling agents such as titanate-, silane-, zirconaluminate-, and alumina-type coupling agents, silylating agents, silanol- modified silicone oil, alkoxy-modified silicone oil, and SiH-modified silicone oil. Less than 2 weight percent of the coating material is generally used with from about 0.2 to about 1 weight percent based on the weight of the zinc oxide being preferred.
  • Examples wear specimens were prepared by machining test blocks of the composition described. A 6.35mm (0.25") wide contact surface of a wear/friction test block was machined to such a curvature that it conformed to the outer circumference of a 35mm (1.38”) diameter X 8.74mm (0.34") wide metal mating ring. The blocks were oven dried and maintained over desiccant until tested. Wear tests were performed using a Falex No. 1 Ring and Block Wear and
  • Friction Tester The equipment is described in ASTM Test method D2714. After weighing, the dry block was mounted against the rotating metal ring and loaded against it with the selected test pressure. Rotational velocity of the ring was set at the desired speed. No lubricant was used between the mating surfaces.
  • the rings were SAE 4620 steel, Re 58-63, 6-12 RMS. A new ring was used for each test.
  • Test time was 24 hours, except when friction and wear were high, in which case the test was terminated early.
  • the friction force was recorded continuously.
  • the block was dismounted, weighed, and the wear calculated by the following calculation:
  • Wear Volume Calculation wear volume(cc/hr) weight loss (grams) material density(g/cc)X test duration(hr)
  • PV (pressure X velocity) limit tests were performed using the same Falex No. 1 Ring and Block Wear and Friction Tester. In these tests, wear blocks and rings were started at a given PV. At intervals of 10-20 minutes, the PV was increased in increments by increasing the velocity to a maximum of 2.67 mps
  • SEM/EDX Scanning Electron Microscopy/Energy Dispersive X-ray analysis was used in determining dispersion of PTFE in the samples of the Examples.
  • This analytical technique provides morphological and elemental composition information from the sample surface. Using commercially available microscopes and x-ray analyzers, the sample is placed in a vacuum chamber, and a primary beam of electrons is rastered across the surface. Images are obtained from the remission of electrons. Elemental information is derived from the emission of x-rays whose energy levels are characteristic of each element. Mapping of individual elements is achieved by limiting detection to desired energy level. The analyzer then applies a light dot on a grid location each time an x-ray of that energy is detected. As the primary beam rasters across the sample surface, a map of the x-ray sources, representing the corresponding element, is generated. The resolution of the elemental map can be improved by multiple passes over the sample surface and averaging the acquired signals.
  • the pellets were molded into standard 6.4 mm thick ASTM (D638) tensile test bars using a 170 g capacity, 145 ton clamping pressure injection molding machine.
  • the profile was as follows: Rear 313°C, Center 334°C, Front 335°C and Nozzle 332°C; Boost 1 sec, Injection 20 sec, Hold 20 sec, Injection Pressure 3.4 MPa, Ram Speed fast, Screw Speed 107 rpm and Back Pressure minimum.
  • the pellets were molded into standard 6.4 mm thick ASTM (D638) tensile test bars using a 170 g capacity, 145 ton clamping pressure injection molding machine.
  • the profile was as follows: Rear 313°C, Center 334°C, Front 335°C and Nozzle 332°C; Boost 1 sec, Injection 20 sec, Hold 20 sec, Injection Pressure 3.4 MPa, Ram Speed fast, Screw Speed 107 rpm and Back Pressure minimum.
  • Example 2 The same method for sample preparation as used in Example 2 was utilized except the polyimide resin prepared from pyromellitic dianhydride and 4,4' -oxydianiline was individual component is documented in the table below.
  • Samples XVII, XVIII, and XIX were prepared as in Example 1 using 56 parts of Zenite® 6000 and 24 parts of polyamic acid, except that the zinc oxide used was 503R obtained from Zinc Corporation of America having a mean particle size of 3.7 ⁇ m after coating and no discernible unique structure.
  • Sample XVIII utilized a zinc oxide coated according to the following procedure: To a 5 L round bottom flask 2L of distilled water and 500 g zinc oxide were added with agitation. The dispersion was heated to 75°C, and the pH was adjusted to 8.7.
  • Sample XIX utilized a zinc oxide coated according to the following procedure: To a 5 L round bottom flask 3L of distilled water and 500 g zinc oxide was added with agitation. The dispersion was heated to 75°C and the pH was adjusted to 9.5 with 30% sodium hydroxide solution. 42.5g Kasil (Vinnings VSA-38) diluted to 100 ml with distilled water was added over a 30 minute period keeping the pH at 9.5 with 17.5% HCl solution. The dispersion was stirred for 30 minutes. The pH was adjusted to 8.2 with 17.5% HCl solution, and 40 ml of alumina was added over a 30 minute period while maintaining a pH of 8.2 with a 17.5% solution of hydrochloric acid. The dispersion was stirred for 30 minutes then filtered, washed with distilled water and placed in an oven at 110°C until dried. The sample was sonified to the desired particle size.
  • Sample XX was prepared according to Example 1 using 56 parts of Zenite® 6000 and 24 parts of polyamic acid precursor. WZ-511 Zinc oxide powder was used as received from the supplier.
  • HTN HTN blended with 10 parts zinc oxide additive (obtained from Matsushita as WZ-51 1 powder) having a starting mean particle size of 2.1 ⁇ m, 10 parts PTFE (DuPont Teflon® MP-1600 micropowder) and 24 parts polyimide resin prepared from pyromellitic dianhydride and 4,4' -oxydianiline (present as its precursor, polyamic acid) in such quantity as to yield the percentages shown in the table below. This was accomplished using a 30mm twin screw extruder with barrels set to 320°C and the die at 335°C. Quenching was accomplished using a water spray. The strand was cut into pellets using a standard rotating blade cutter.
  • the pellets were molded into standard 6.4 mm thick ASTM (D638) tensile test bars using a 170 g capacity, 145 ton clamping pressure injection molding machine.
  • the profile was as follows: Rear 315°C, Center 335°C, Front 335°C and Nozzle 335°C; Boost 0.5 sec, Injection 20 sec, Hold 20 sec, Injection Pressure 4.8 MPa, Ram Speed fast, Screw Speed 120 rpm and 0.34 MPa Back Pressure.
  • Sample XXIV utilized imidized polyimide powder resin prepared from pyromellitic dianhydride and 4,4' -oxydianiline.
  • Samples were prepared as in Example 1 using 10 parts of zinc oxide to 10 parts of PTFE.
  • the compounded resin was injection molded into a 1.5mm thick by 50.8mm diameter disk for use as a hysterisis washer.
  • the conditions utilized to accomplish this were as follows: Barrel temperatures 320°C. rear, 335°C. front, 335°C. nozzle: Mold 100°C; Cycle 1 sec boost, 15 sec inject, 20 sec cool; Pressure 0.3MPa back, 2.7MPa boost, 2.4MPa Inject; Ram speed, fast; Screw 84rpm.
  • the washer performed as required with little evidence of wear after 10,000 kilometers of service.

Abstract

L'invention concerne des compositions polymères comportant des quantités contrôlées de particules d'oxyde de zinc uniformément dispersées à l'intérieur de celles-ci, des polymères et copolymères de tétrafluoroéthylène de dimension et de poids moléculaire sélectionnés, qui permettent d'obtenir des article façonnés dotés de propriétés d'usure améliorées.
PCT/US1997/014510 1996-08-19 1997-08-19 Compositions thermoplastiques comportant de l'oxyde de zinc et des homo ou copolymeres de tetrafluoroethylene et articles façonnes a partir de celles-ci WO1998007779A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
CA002263323A CA2263323A1 (fr) 1996-08-19 1997-08-19 Compositions thermoplastiques comportant de l'oxyde de zinc et des homo ou copolymeres de tetrafluoroethylene et articles faconnes a partir de celles-ci
JP51087098A JP2001524992A (ja) 1996-08-19 1997-08-19 酸化亜鉛およびテトラフルオロエチレンのホモポリマーまたはコポリマーを含有する熱可塑性組成物ならびにそれから調製された成形品
EP97937306A EP0918816A1 (fr) 1996-08-19 1997-08-19 Compositions thermoplastiques comportant de l'oxyde de zinc et des homo ou copolymeres de tetrafluoroethylene et articles fa onnes a partir de celles-ci
AU39849/97A AU3984997A (en) 1996-08-19 1997-08-19 Thermoplastic compositions including zinc oxide and tetrafluoroethylene homo or copolymers and shaped articles prepared therefrom

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US69704996A 1996-08-19 1996-08-19
US08/697,049 1996-08-19

Publications (2)

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WO1998007779A1 WO1998007779A1 (fr) 1998-02-26
WO1998007779A9 true WO1998007779A9 (fr) 1998-07-02

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EP (1) EP0918816A1 (fr)
JP (1) JP2001524992A (fr)
KR (1) KR20000068198A (fr)
CN (1) CN1228796A (fr)
AU (1) AU3984997A (fr)
CA (1) CA2263323A1 (fr)
WO (1) WO1998007779A1 (fr)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6013719A (en) * 1998-06-15 2000-01-11 E. I. Du Pont De Nemours And Company Applications of low melt viscosity polytetrafluorethylene
WO2014199322A2 (fr) * 2013-06-12 2014-12-18 Sabic Innovative Plastics Ip B.V. Compositions résistantes à l'usure avec une faible contamination particulaire et procédé de préparation de ces compositions

Family Cites Families (7)

* Cited by examiner, † Cited by third party
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US3908038A (en) * 1973-03-28 1975-09-23 Allied Chem Thermoplastic molding compositions
US3994814A (en) * 1973-07-12 1976-11-30 Garlock Inc. Low friction bearing material and method
JP2531307B2 (ja) * 1991-01-08 1996-09-04 住友化学工業株式会社 全芳香族ポリエステル樹脂組成物およびオ―ブンウエア
JP3041071B2 (ja) * 1991-04-05 2000-05-15 松下電器産業株式会社 静電気拡散性摺動部材用樹脂組成物
JP3142673B2 (ja) * 1992-12-25 2001-03-07 エヌティエヌ株式会社 複写機用分離爪
US5567770A (en) * 1993-05-28 1996-10-22 E. I. Du Pont De Nemours And Company Liquid crystalline polymer blends with improved wear properties
JPH08104803A (ja) * 1994-10-03 1996-04-23 Idemitsu Petrochem Co Ltd 樹脂組成物

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