US3026570A - Process for the production of shaped parts of polyethylene - Google Patents

Process for the production of shaped parts of polyethylene Download PDF

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Publication number
US3026570A
US3026570A US664515A US66451557A US3026570A US 3026570 A US3026570 A US 3026570A US 664515 A US664515 A US 664515A US 66451557 A US66451557 A US 66451557A US 3026570 A US3026570 A US 3026570A
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United States
Prior art keywords
polyethylene
shaped parts
pressure
production
pressures
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US664515A
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English (en)
Inventor
Beck Kurt
Roelen Otto
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Ruhrchemie AG
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Ruhrchemie AG
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Publication date
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Classifications

    • D—TEXTILES; PAPER
    • D03—WEAVING
    • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
    • D03D49/00—Details or constructional features not specially adapted for looms of a particular type
    • D03D49/24—Mechanisms for inserting shuttle in shed
    • D03D49/26—Picking mechanisms, e.g. for propelling gripper shuttles or dummy shuttles
    • D03D49/38—Picking sticks; Arresting means therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/006—Pressing and sintering powders, granules or fibres
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/02—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of definite length, i.e. discrete articles
    • B29C43/14—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of definite length, i.e. discrete articles in several steps
    • D—TEXTILES; PAPER
    • D03—WEAVING
    • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
    • D03D49/00—Details or constructional features not specially adapted for looms of a particular type
    • D03D49/24—Mechanisms for inserting shuttle in shed
    • D03D49/26—Picking mechanisms, e.g. for propelling gripper shuttles or dummy shuttles
    • D03D49/36—Pickers; Arresting means therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2791/00—Shaping characteristics in general
    • B29C2791/001—Shaping in several steps
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/04—Polymers of ethylene
    • B29K2023/06—PE, i.e. polyethylene
    • B29K2023/0658—PE, i.e. polyethylene characterised by its molecular weight
    • B29K2023/0683—UHMWPE, i.e. ultra high molecular weight polyethylene
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
    • B29K2105/25—Solid
    • B29K2105/251—Particles, powder or granules
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/04—Homopolymers or copolymers of ethene
    • C08L23/06—Polyethene

Definitions

  • shaped parts having particularly high impact and shock resistance can be produced of polyethylene with very good success if finely divided polyethylene, especially polyethylene powder having molecular weights above 500,000, e.g., above 1,000,000, is compressed in several pressure stages with the pressing in the second compression stage, and, if necessary or desired, in the subsequent compression stages being carried out under the simultaneous action of heat, until the material is plastified, whereupon the plastified material is further compressed at room temperature in a final compression stage.
  • finely divided polyethylene especially polyethylene powder having molecular weights above 500,000, e.g., above 1,000,000
  • stampings having larger dimensions than those of the finished parts are first produced by mechanical pressure, and preferably at room temperature. These stampings are subsequently converted into sintered and plastified polyethylene by the simultaneous use of heat and the renewed action of mechanical pressure.
  • the compression in the last stage should be preferably carried out at higher pressure than in the sintering stage.
  • the invention is based on the discovery that it is required for simultaneously obtaining increased strength and accuracy of size that the total pressure to be applied for this purpose be subdivided into several stages. It is already known to produce shaped parts of polyethylene by cold pressing and subsequent sintering under pressure. It was observed, however, that the parts produced in this manner show a resilience similar to that of rubber, which is evidenced by the fact that the reduction in volume obtained in hot pressing is cancelled out when subjecting the parts to mechanical and/or thermal stresses. Therefore, neither increased mechanical strength nor dimensional stability can be obtained in this manner.
  • the process of the invention eliminates this disadvantage by applying at least a third mechanical compressing, thereby permanently removing the above-mentioned elastic recovery of the shape at room temperature or approximately room temperature. It was possible, therefore, to produce articles of polyethylene which were insensitive to most severe stresses by shock or impact to an extent not known up to the present for any other nonmetallic material.
  • the process of the invention is of the particular importance for the production of loom fittings. It is possible, for example, to produce pickers for looms, the life of which under identical service conditions is twice to three times or more that of the rawhide pickers previously used.
  • the total pressure to be applied may also be subdivided into more than three stages. For example, it may be favorable in sintering to reach the final pressure in several successive pressure stages. Moreover, in compressing the sintered part to dimensional stability, it may likewise be preferable to use several pressure stages.
  • the pressures applied in the hot treatment and in the subsequent cold pressing be in an appropriate ratio.
  • the pressures applied at the end of the treatment should be highest and preferably be a multiple of those used in hot pressing.
  • the pressures given in this description are the specific pressures in terms of kg./sq. cm. rather than the absolute pressures on the whole surface of any part.
  • the sintering step may be effected at pressures up to kg./sq. cm.; for reasons of keeping the size of the technical equipment small, it is desirable to keep the pressures within this low range. Moreover, it is not advantageous in connection with the desired properties of the material to apply much higher pressures to the heated material. On the other hand, it has been found to be advantageous to effect the third or subsequent pressing of the sintered material with substantially much higher pressures, as, for example, 200l000 kg./sq. cm. As experience has shown, parts obtained by multi-stage pressing in the manner described above retain, in addition to unreduced toughness, the desired shock and impact-resistance which is due to the high density.
  • the process permits the manufacture of shaped parts, subjected to shock and impact, for the construction of various apparauts, for electrical engineering, as well as for gears.
  • Shaped parts, produced in accordance with the invention are, moreover, particularly suitable for sound-absorbing shock spots which have to retain dimensional stability to a more or less high degree.
  • the production of hammers and handles is also possible.
  • the particular importance of the process resides in the manufacture of loom fittings such as take-up rollers, feed rolls, buffers, picker protections, pickers, spindle rings, and the like.
  • Example 1 The polymerization of ethylene was effected in a vessel of glass with stirrer having a capacity of about 5 liters, into which were filled 2 liters of a C C hydrocarbon fraction from the hydrogenation of carbon monoxide.
  • This hydrocarbon fraotion had been prepared by a hydrogenation effected at 250 C., subsequent refining with sulfuric acid, and intensive drying.
  • the catalyst solution was added while stirring and passing ethylene through the vessel.
  • the catalyst solution had been prepared by mixing together 100 cc. of the same C S hydrocarbon fraction, 1.08 grams of diethyl aluminum monochloride, and 0.42 gram of titanium tetrachloride, and vigorously shaking the mixture for about 30 minutes.
  • the reaction temperature was adjusted to about 75 C. After a reaction time of 12 hours, 472 grams of polyethylene had formed.
  • the mixture was filtered and the filter residue was treated with five times its quantity of 1% aqueous sodium hydroxide solution in a stirring flask.
  • the mixture was then heated to the boiling point, thereby distilling off the residues of the hydrocarbon fraction to gcther with the water vapor.
  • the residue from distillation was finally washed with water to free it from alkali, and was then dried.
  • the polyethylene obtained had a molecular weight of 1,100,- 000, as determined viscosimetrically.
  • This polyethylene powder at a specific pressure of about 110 kg./sq. cm., was compressed into a sheet of 30 mm. thickness and 100 X 80 cm. size.
  • This sheet was subsequently plastified for 8 hours between heated metal plates at a temperature of 150 C. and a specific pressure of 10 kg./sq. cm. Cooling was effected under the same pressure. There was obtained a sheet of plastified polyethylene having a density of 0.96. From this sheet, picker slugs were produced by cutting. The slugs were subsequently separately stamped at a pressure of about 750 kg./sq. cm., i.e. shaped by cold-pressing, whereby they were given their final shape. When used in a loom, the pickers produced in this manner resisted to 14 million picks, while rawhide pickers of the same shape were no longer usable after only 4.5 million picks.
  • the accompanying flowsheet shows a diagram or the operation according to the present invention.
  • the polyethylene is fed from a storage hopper by way of a scale into the first press. From there, the pretreated material enters the heated press. The plastification and sintering steps both are carried out in this heated press. The material then is given its final forming in the last press and thereafter is removed to the finishing operation, not
  • plastification and plastified as used in this specification denote that the polyethylene has been brought into a plastic state.
  • a process for the production of shaped parts of polyethylene, said parts having particularly high shockand impact resistance, accuracy of size and size retention which comprises compressing finely divided polyethylene, having a molecular weight above 500,000, in a first stage to approximately kg./cm. at room temperature to effect sintering; lowering the compression, in a second pressure stage, to approximately 10 kg./cm. at approximately 0., thereby effecting complete plastification of the polyethylene; cooling the polyethylene to room temperature while maintaining the same pressure; and compressing at room temperature to approximately 2001,000 kg./cm. in a final stage.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Textile Engineering (AREA)
  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)
  • Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)
  • Artificial Filaments (AREA)
  • Woven Fabrics (AREA)
US664515A 1956-06-21 1957-06-10 Process for the production of shaped parts of polyethylene Expired - Lifetime US3026570A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DER19111A DE1266481B (de) 1956-06-21 1956-06-21 Verfahren zum Herstellen von Webstuhlpickern aus Polyaethylen

Publications (1)

Publication Number Publication Date
US3026570A true US3026570A (en) 1962-03-27

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ID=7400353

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Application Number Title Priority Date Filing Date
US664515A Expired - Lifetime US3026570A (en) 1956-06-21 1957-06-10 Process for the production of shaped parts of polyethylene

Country Status (6)

Country Link
US (1) US3026570A (it)
BE (1) BE558103A (it)
DE (1) DE1266481B (it)
FR (1) FR1175520A (it)
GB (1) GB848859A (it)
NL (2) NL208935A (it)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3268642A (en) * 1962-04-11 1966-08-23 Becker & Van Huellen Method of and device for making pressboards and the like
US3944536A (en) * 1973-06-18 1976-03-16 E. I. Du Pont De Nemours & Company Exceptionally rigid and tough ultrahigh molecular weight linear polyethylene
US4110391A (en) * 1976-07-31 1978-08-29 Ruhrchemie Aktiengesellschaft Process for the manufacture of molded articles from polyolefins with molecular weights of at least one million

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA989127A (en) * 1971-03-01 1976-05-18 Norbert L. Bradley Scrapless forming of plastic articles

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2232475A (en) * 1938-04-19 1941-02-18 Ici Ltd Process of molding polyethylene
US2736925A (en) * 1953-06-08 1956-03-06 Jerome S Heisler Method of forming hollow articles from polyethylene
US2781552A (en) * 1955-10-21 1957-02-19 Us Ceramic Tile Company Process for making thin articles of polytetrafluoroethylene

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH1303A (de) * 1889-08-20 1890-04-15 Emanuel Hausmann Apparat an Stickmaschinen zum Ansticken von Medaillons jeder Art
DE652990C (de) * 1935-07-26 1937-11-13 I G Farbenindustrie Akt Ges Vorrichtung zum Aufbereiten bildsamer Massen, insbesondere keramischer und Kautschukmassen, mit zwei ineinandergreifenden, breitgaengigen Schnecken
DE697132C (de) * 1935-10-26 1940-10-07 Siemens & Halske Akt Ges Verfahren zum Herstellen von Formkoerpern aus Polystyrol
NL60736C (it) * 1942-11-24
DE899550C (de) * 1944-04-29 1953-12-14 H D Justi & Son Inc Verfahren und Vorrichtung zum Formen von Gegenstaenden aus thermoplastischen und optisch voneiander unterscheidbaren Kunststoffen
DE856525C (de) * 1944-09-03 1952-11-24 I G Farbenindustrie A G In Abw Verfahren zur Herstellung von Formgegenstaenden aus Polyvinylchlorid
AT163168B (de) * 1945-01-24 1949-05-25 Chem Fab Schoenenwerd Verfahren und Vorrichtung zur Herstellung von Polymerisaten in der Form
DE812476C (de) * 1948-10-02 1951-08-30 Karl Malz Verfahren und Einrichtung zur Verarbeitung von thermoplastischen Kunststoffen
CH266448A (de) * 1948-10-03 1950-01-31 Ehrbar Jakob Verfahren zur Plastifikation thermoplastischer Kunststoffe.
DE877194C (de) * 1951-11-08 1953-05-21 Heinze Fa R Verfahren zur Herstellung masshaltiger und/oder fliessnahtfreier thermoplastischer Kunststoffkoerper, z. B. Tastenknoepfe, Zahlenrollen od. dgl.
DE918231C (de) * 1952-11-25 1954-09-23 Mueller Welt Fa Verfahren und Vorrichtung zum Herstellen von Linsen mit Zentrierrand oder von mit einem Tragrand versehenen Haftglaesern aus thermoplastischen durchsichtigen Kunststoffen
DE956353C (de) * 1954-07-03 1957-01-17 Siemens Ag Schneckenpresse zur Aufbereitung und Verarbeitung von plastischen Massen, insbesondere thermoplastischen Kunststoffen

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2232475A (en) * 1938-04-19 1941-02-18 Ici Ltd Process of molding polyethylene
US2736925A (en) * 1953-06-08 1956-03-06 Jerome S Heisler Method of forming hollow articles from polyethylene
US2781552A (en) * 1955-10-21 1957-02-19 Us Ceramic Tile Company Process for making thin articles of polytetrafluoroethylene

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3268642A (en) * 1962-04-11 1966-08-23 Becker & Van Huellen Method of and device for making pressboards and the like
US3944536A (en) * 1973-06-18 1976-03-16 E. I. Du Pont De Nemours & Company Exceptionally rigid and tough ultrahigh molecular weight linear polyethylene
US4110391A (en) * 1976-07-31 1978-08-29 Ruhrchemie Aktiengesellschaft Process for the manufacture of molded articles from polyolefins with molecular weights of at least one million

Also Published As

Publication number Publication date
NL208935A (it)
GB848859A (en) 1960-09-21
BE558103A (it)
DE1266481B (de) 1968-04-18
NL99897C (it)
FR1175520A (fr) 1959-03-27

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