United States Patent (19) 11 Patent Number: 4,481,333 Fleischer et al. 45 Date of Patent: Nov. 6, 1984 54 THERMOPLASTIC COMPOSITIONS 58 Field of Search ................................ 525/192, 199 COMPRISING WINYL CHLORIDE POLYMER, CLPE AND FLUOROPOLYMER 56) References Cited U.S. PATENT DOCUMENTS 75) Inventors: Dietrich Fleischer, Darmstadt; Eckhard Weber, Liederbach; 3,005,795 10/1961 Busse et al. ......................... 525/199 3,294,871 2/1966 Schmitt et al. ...... 52.5/154 X Johannes Brandrup, Wiesbaden, all 3,299,182 1/1967 Jennings et al. ... ... 525/192 of Fed. Rep. of Germany 3,334,157 8/1967 Larsen ..................... ... 525/99 73 Assignee: Hoechst Aktiengesellschaft, Fed. 3,940,456 2/1976 Fey et al. ............................ 525/192 Rep. of Germany Primary Examiner-Carman J. Seccuro (21) Appl. No.: 566,207 Attorney, Agent, or Firm-Connolly & Hutz 22 Filed: Dec. 28, 1983 57 ABSTRACT 30 Foreign Application Priority Data The invention relates to a thermoplastic composition which comprises vinyl chloride polymers and chlori Dec. 31, 1982 (DE Fed. Rep. of Germany ....... 3248.731 nated polyethylene and which contains finely divided 51) Int. Cl. ...................... C08L 23/28; C08L 27/06; fluoropolymers and has a markedly improved process C08L 27/18 ability, particularly when shaped by extrusion. 52 U.S. C. .................................... 525/192; 525/199; 525/239 7 Claims, No Drawings 4,481,333 2 iaries and do not provide a solution to the present prob THERMOPLASTC COMPOSITIONS lem. COMPRISINGVINYL CHLORIDE POLYMER, The object of the invention was, therefore, to avoid, CLPE AND FLUOROPOLYMER completely or substantially, the disadvantages de 5 scribed above and, in particular, to provide a thermo It is known that fluoropolymers and, in particular, plastic composition based on vinyl chloride polymers polytetrafluoroethylene, have a very low coefficient of and chlorinated low-pressure polyethylene which has sliding friction and are therefore recommended as an improved processing properties, in particular when additive for other plastics in quantities of 10-30 parts by shaped by extrusion, and which can also be prepared in weight, in order to exert an advantageous effect on the O a simple manner. anti-friction properties of articles molded from these It has now been found that the desired objective can plastics. In this case the fluoropolymer (polytetrafluoro be achieved in a surprisingly simple manner if the chlo ethylene) is employed as a filler. rinated polyethylene is first mixed, on its own, with a Thus German Auslegeschrift No. 1,286,302 describes fluoropolymer, or-which is less preferable-if the the addition of polytetrafluoroethylene to other organic 15 chlorination of the polyethylene for the preparation of polymers including also polyvinyl chloride (PVC), in the chlorinated polyethylene is already effected in the order to control the processing properties and the melt presence of a fluoropolymer and the chlorinated poly viscosity of these polymers. According to the teaching ethylene thus obtained is then mixed with the vinyl of this German Auslegeschrift, it is essential for this that chloride polymer. the polytetrafluoroethylene should be in a micro-fibrous 20 The invention therefore relates to a thermoplastic or submicro-fibrous form and that, after being mixed composition composed essentially of: with a polymer, the bulk of the polytetrafluoroethylene (A) 97 to 80% by weight of a vinyl chloride polymer particles should have a diameter below the resolving and power of an optical microscope. A further requirement (B) 3 to 20% by weight of a chlorinated low-pressure for the use of polytetrafluoroethylene particles in accor 25 polyethylene, wherein, before the components (A) and dance with this publication is that the polytetrafluoro (B) are mixed, the component (B) is mixed with 0.01 to ethylene particles must be capable of adhering to one 2.0% by weight, relative to the chlorinated low-pres another and of forming a coherent composition. Poly sure polyethylene, of a finely divided fluoropolymer. ethylene particles which do not adhere to one another The invention also relates to a thermoplastic compo are, therefore, not suitable. The prescribed fine disper 30 sition composed essentially of: sion of the polytetrafluoroethylene is effected by inten (A) 97 to 80% by weight of a vinyl chloride polymer sively grinding the polymer, mixed with polytetrafluo and roethylene, in a fusible state and, for this reason alone, (B) 3 to 20% by weight of a chlorinated low-pressure would be completely unsuitable for the technique of polyethylene, wherein a chlorinated low-pressure poly preparing PVC dry blends. 35 ethylene which has been prepared by chlorinating low It is stated in German Offendegungsschrift No. pressure polyethylene in an aqueous or aqueous hydro 1,694,338 that the processing properties of PVC are chloric acid suspension is used, and wherein 0.01 to improved by enveloping the individual particles of the 2.0% by weight, relative to polyethylene, of a finely pulverulent PVC with selected polymer coatings. Coat divided fluoropolymer have been added to the chlorina ing polymers which are preferred in this respect are tion liquor, excluding chlorinated low-pressure polyeth fluorocarbon polymers. The PVC particles are envel ylenes which are obtained by chlorinating low-pressure oped by coating them with a fluorine-containing mono polyethylene in the presence of 0.3 to 1.5% by weight mer which is then polymerized in a suitable manner, for of a polytetrafluoroethylene wax having a molecular example by means of organic peroxides. 45 weight of 10 to 106 and a particle size of 0.1 to 10.0 um A procedure of this type for improving the process and, additionally also 0.01 to 1.1% by weight of silica ing properties of PVC is very tedious and expensive and which has been rendered hydrophobic and has a parti conflicts with the practical use of fluorocarbon poly cle size of about 7 to 18 nm and 0.5 to 3.5% by weight mers for this purpose, especially since tetrafluoroethyl of an inert inorganic additive which has a high absorp ene, which has a boiling point of -76. C., cannot, in 50 tive capacity for low-pressure polyethylene. accordance with the teaching of this German Offen In accordance with the invention it is possible, in legungsschrift, be polymerized in an aqueous dispersion principle, to employ the known fluoropolymers accord to form a polymeric coating without the use of pressure. ing to employ the known fluoropolymers according to There has also been no lack of attempts to improve the state of the art, but the latter should preferably the processing properties of high impact strength PVC 55 already be in an appropriately finely divided state and compositions, which are difficult to process, by adding should have an average particle size within the range lubricants, for example metal stearates, polyethylene from 0.05 to 50 um, preferably 0.1 to 10 um. The fluoro waxes, fatty acid esters and the like or other additives. polymer can be used here either in the form of powder As well as being only moderately successful, additives or in the form of dispersions; in the latter case the dis of this type often exhibit undesirable side effects which 60 persion medium is preferably an organic liquid which is manifest themselves, for example, in surface markings of readily compatible with PVC and chlorinated polyeth the visual surface of extruded sections, and tend under ylene, such as, for example, an aqueous solution of the certain circumstances to exude (plate out) or impair the ammonium salt of perfluorooctoic acid or, for instance, plasticization process. This also applies to attempts to dioctyl phthalate and the like. Dispersions of this type improve the processing properties of PVC/CPE mix 65 can have a fluoropolymer content (relative to the total tures by adding finely divided polytetrafluoroethylene dispersion) of 10 to 50% by weight, preferably 15 to to these mixtures. The results fall more or less within 25% by weight; the particle size is in most cases within the range of results achieved by other processing auxil the range from 0.1 to 10 um, preferably 0.2 to 4 um. 4,481,333 3 4. The term "fluoropolymers' is to be understood here ylene. This is effected by adding the fluoropolymer, for as meaning polymers which preferably contain at least example in the form of powder, to the aqueous or aque 50% by weight, in particular at least 70% by weight, ous hydrochloric acid suspension during the chlorina relative to the polymer, of fluoroolefin units, and which tion reaction, which is carried out in the conventional have thermoplastic properties. Examples of fluoroole 5 ae, fins which may be mentioned here are tetrafluoroethyl The thermoplastic composition according to the in ene, trifluorochloroethylene, vinyl fluoride and vinyli vention contains 97 to 80% by weight, preferably 90 to dene fluoride, and examples of corresponding polymers 80% by weight, of polyvinyl chloride or a copolymer of are polytetrafluoroethylene, polytrifluoroethylene, pol vinyl chloride with other comonomers. The following yvinyl fluoride and polyvinylidene fluoride, and also 10 are examples of possible comonomers: olefins, such as corresponding copolymers containing mixtures of such ethylene or propylene, vinyl esters of linear or branched fluoroolefin units and/or units derived, for example, carboxylic acids having 2 to 20, preferably 2 to 4, car from hexafluoropropene or from olefins, such as ethyl bon atoms, such as vinyl acetate, propionate, butyrate, ene, and from fluorinated ethers, in particular per 2-ethylhexoate or stearate or vinyl isotridecanoate; fluoro(alkyl-vinyl)ethers, such as perfluoropropyl per 15 vinyl halides, such as vinyl fluoride, vinylidene fluoride fluorovinyl ether. Homopolymers and copolymers of or vinylidene chloride; vinyl ethers, such as vinyl this type are described, for example, in German Offen methyl ether; vinylpyridine; unsaturated acids, such as legungsschrift No.