Method to manufacture items from polymer composite materials based on polytetrafluorethylene and device for manufacturing of items
FIELD: technological processes.
SUBSTANCE: invention relates to the field of material science, in particular, to anti-friction polymer composite materials, and may be used in manufacturing of parts of metal-polymer friction units and in general machines of various types of equipment. The method to manufacture items from polymer composite materials on the basis of polytetrafluorethylene consists in the fact that fillers are mixed with polytetrafluorethylene in a mixer with rotation frequency of 2800 min-1, and cold pressing is carried out in a closed die mould. Then the pressed stock is installed into the closed device, and additional pressure of compression is developed in the pressing direction. Besides, the additional pressure of compression is regulated and set within 2.0 - 8.0 MPa.
EFFECT: increased characteristics of mechanical and tribotechnical properties of a composite material based on polytetrafluorethylene.
1 tbl, 1 dwg
The invention relates to the field of materials, particularly to antifriction polymeric composite materials (PCM), and can be used in the manufacture of metal-polymer friction and, in General, machines of various types of equipment. The known method of manufacturing products from polymer composite materials based on polytetrafluoroethylene (PTFE) (AC No. 1812190, IPC C08J 5/15) at which PTFE powders, bronze, molybdenum disulfide and chopped carbon fibers are mixed in a mixer with a rotational speed of the knives 2800 min-1pressed preform at a pressure of 100-110 MPa and sintered at a temperature of 360±5°C, aged at this temperature, the rate of 8-9 min per 1 mm of wall thickness of the workpiece is cooled from the sintering temperature to 327°C at a rate of 0.3-0.4 deg./min, 327 to 20°C freely together with the furnace. With chopped carbon fiber is produced from a carbon-based material, stored in liquid freon at least 48 hours. After drying, the material is cut into pieces and ground in a mill in the presence of the PTFE powder at a frequency of rotation of the knives 7000 min-1within 3-9 minutes Known method has the disadvantages of reducing characteristics of the mechanical properties of the composite material and the efficiency of the method. The main disadvantage of this method is that during cold compaction cannot be achieved eno�but dense packing of the particles of the matrix and fillers. In addition, under free sintering the molded workpiece, due to different thermal expansion of the components, their sizes and the amount of PTFE particles and the filler is changed to a different value, which leads to the weakening and destruction of adhesion bonds formed between them at the stage of extrusion, and to the increase of porosity. Upon further cooling with free cooling outside shape level of adhesive interaction and porosity recover slightly, resulting in a reduction of mechanical characteristics and tribological composite properties (tensile strength, wear rate, etc.). Processing of carbon fiber in the liquid refrigerant within 48 hours also provides the solution to this problem, a twofold increase in compaction pressure to 100-110 MPa only partially contributes to the increased packing density of the particles. As a result, the tensile strength and the wear resistance of the composite material are reduced, increasing production costs (spent freon, increase energy expenditure and wear of extrusion equipment) and decreases the performance. Another known method of manufacturing products made of composite materials based on polytetrafluoroethylene with particulate and fibrous fillers, which carry out the mixing of the filler� with polytetrafluoroethylene in a mixer with a rotation speed of at least 2800 min -1, cold pressing in the mould when exposed to pressing punch of energy of ultrasonic oscillations of a frequency of 20±3 kHz within 2-3 min and the amplitude of the oscillations, in the range of 8-12 μm, is heated in a furnace to a temperature of 360±5°C at a rate of 1.5-2.0 deg./min, holding at this temperature for 8-9 min per 1 mm of wall thickness of the product, cooling to a temperature of 327°C at a rate of 0.3-0.4 deg./min to and from 327°C to room temperature - cooling with the furnace (Patent RF №2324708 C2, IPC C08J 5/14, publ. 20.05.2008).
The method closest in its technical essence to the proposed invention, however, it also has its disadvantages, which reduce the mechanical characteristics and tribological properties of the composite material. Practically eliminates the disadvantage associated with the destruction of adhesion between the particles of the components, with free heated, extruded workpieces, since pressing with the imposition of energy of ultrasonic oscillations, increasing the level of adhesion interaction may not affect the difference in thermal expansion of the material of the various components. Consequently, and inevitably, the reduction in mechanical properties of the composite material. In addition, when using ultrasonic compacting is much more complicated technological equipment (optional n�wives ultrasonic generator) and additional tooling in the form of a special waveguide for transmission of ultrasound energy pressing the punch.
The technical result of the invention - improving mechanical characteristics and tribological properties of composite material based on PTFE, and the simplification of process equipment and technology of manufacturing products made of composite materials based on polytetrafluoroethylene.
Said technical result is achieved in that in the method of manufacturing products made of composite materials based on polytetrafluoroethylene, which carry out the mixing of fillers with PTFE in the mixer with a rotational speed 2800 min-1, cold pressing in a closed mold, the installation of the molded workpiece in a closed device, the creation of additional compression pressure in the press direction, according to the claimed invention, additional pressure regulate and compression set in the range of from 2.0 to 8.0 MPa.
The compression pressure, adjustable between 2 and 8 MPa, creates stress-strain state in the volume of the molded workpiece and ensures the preservation and strengthening of adhesion bonds between the components formed during the extrusion of the composition, and significantly improves the characteristics of the mechanical and tribological properties of polymer composite materials.
The minimum value of the compression pressure of 2.0 MPa creates pressure compression and deformation zagotovka�, necessary to compensate for possible volume changes due to thermal expansion of the elements of the closed device and variability of body sizes and punch-defined tolerances in their manufacture.
The maximum compression pressure of 8.0 MPa is determined by the tensile and yield strength of PTFE in compression and recrystallization process, which begins when a certain magnitude of stress and strain.
Review the effectiveness of the claimed method was performed on manufacture and research of PCM following composition: cryptocrystalline graphite 4,5-9,0 masses. %, molybdenum disulfide 1.0 to 2.5 mass. percent, carbon nanotubes of 1.0-2.5 mass. %, PTFE - else (86,0-93.5 masses. %).
Manufacturing (PCM samples for the study of mechanical and tribological properties) was produced as follows. Composition of powders are mixed in a mixer with a rotational speed of the blades is not less than 2800 min-1, extruded workpiece under a pressure of 75 MPa, pressed billet was placed in a closed device, the geometry of the internal cavity of which corresponds to the geometry and size of the workpiece. Using the adjusting screw to set the pressure of 2.0 MPa and sintered at a temperature of 360±5°C for 8-9 min per 1 mm of wall thickness of the product, cooled in the shape from the sintering temperature to 327°C with soon�TEW of 0.3-0.4 deg./min, and then to room temperature free cooling with the furnace.
The invention is illustrated by the attached drawing, which shows the design in the context of a closed device for sintering the pressed blanks. The device consists of a housing 1, a plug 2, a compression spring 3, the support ring 4 and the adjusting screw 5.
After pressing, the billet 6 is installed in the housing 1, the space is closed by a plug 2, by means of a spring 3 and an adjusting screw 5 defines the necessary compression pressure. Mounted in the housing, the workpiece experiences a predetermined compression pressure, wherein in the heating process completely eliminates thermal expansion, since the workpiece is preliminarily subjected to a compression pressure in the entire volume, which is greatly enhanced owing to the difference of thermal expansion coefficients of steel and PTFE at a temperature of 360°C, 25 times). During heating of the workpiece to 360°C compression pressure between the particles increases 3.5 times.
To quantify the effectiveness of the claimed method was carried out tests of samples made by known and declared methods. The definition of the limit of the tensile strength σinand elongation at break δ produced by methods GOST 11262-80, modulus of elasticity by the method of GOST 9550-81. The wear resistance of PCM was determined �about the speed of wear of the friction drive, under the scheme of friction "thumb drive". Fingers with a diameter of 5 mm were made of the test material, the disc (contrale) - made of hardened carbon steel. The test was carried out at sliding velocity of 1.2 m/s and contact pressure of 1.5 MPa. Table 1 shows the mechanical and tribological properties of samples manufactured according to the known and the claimed method with three modes: by mechanical compression pressure of 2 MPa, at a pressure of 6 MPa and at a pressure of 8 MPa. From these data it follows that in the manufacture of samples of the claimed method, the tensile strength is increased to 35%, the modulus of elasticity of up to 41%, the wear rate decreases to 56%, the coefficient of friction is reduced by 17%.
Complex improvement of the mechanical characteristics and tribological properties of the composite material, manufactured by the inventive method, which is expressed in increasing the tensile strength of 24-35% and reducing the wear rate on 42-56%, can significantly improve the performance and significantly increase the life of friction (bearings, sealing devices) machines in various branches of engineering.
Method of manufacturing products made of composite materials based on polytetrafluoroethylene, which carry out the mixing of fillers with policetype�ethylene in a mixer with a rotational speed 2800 min -1, cold pressing in a closed mold, the installation of the molded workpiece in a closed device, create additional pressure of compression in the direction of extrusion, characterized in that the additional pressure regulate and compression set in the range of from 2.0 to 8.0 MPa.
SUBSTANCE: invention relates to biopharmaceutical tube and product, including such tube. Flexible tube is made of mixture of polyolefin and block-copolymer based on styrene and plasticiser. Styrene-based block copolymer has configuration of blocks A-B-A and molecular weight at least about 350 kg/mol. Polyolefin and styrene-based block-copolymer are present in ratio about 1.2:1 to about 0.2:1.
EFFECT: manufacturing biopharmaceutical flexible tubes and products containing them, possessing improved operating characteristics of pumping.
13 cl, 6 tbl, 3 dwg
SUBSTANCE: invention relates to high-frequency composite dielectric materials used in antenna engineering and high-frequency transmission lines. The composite material comprises packed fluoroplast-4 powder with particle size of no more than 5 mcm, impregnated with binder. The binder used is epoxy resin with a curing agent. The epoxy resin is a product of condensation of epichlorohydrin and aniline in an alkaline medium, with viscosity of no more than 200 mPa·s, and the curing agent used has viscosity of no more than 40 mPa·s. Impregnation with binder is carried out under pressure and while evacuating the volume of the powder, followed by curing.
EFFECT: producing a dielectric material with low permittivity, low dielectric loss tangent and improved properties such as strength and modulus of elasticity in compression.
1 dwg, 1 tbl
SUBSTANCE: invention relates to a product, namely to a power cable, which includes a semiconductor layer, containing a semiconductor polyolefin composition. The composition contains graphene nanoplates, where the average thickness of the graphene nanoplates is in the range from 1 nm to 50 nm, and their side diameter constitutes 200 mcm or less, and olefin polymer resin of the base. The composition for the power cable can additionally contain solid electroconductive filler, different from the graphene nanoplates. The application of the semiconductor polyolefin composition in the semiconductor layer of the power cable is also described. Improvement of electrical exploitation characteristics in the process of annealing at temperatures lower than the temperature of the polymer melting and the temperature dependence of specific volume resistance in comparison to the one that has place for the respective semiconductor polyolefin compositions based on carbon soot.
EFFECT: roughness of the surface of the semiconductor polyolefin composition for extruded samples constitutes 100 mcm and less.
14 cl 7 dwg, 2 tbl
SUBSTANCE: invention relates to the application of butyl ion-containing polymers or partially halogenated butyl ion-containing polymers for the reduction of a population and/or prevention of accumulation of organisms, at least, on the surface of products, in a composite material, and in a moulded product. The organisms can be represented by bacteria, algae, fungi, molluscs or arthropods. A butyl ion-containing polymer is obtained from, at least, one isoolefin monomer and, at least, one multiolefin monomer. The butyl ion-containing polymer contains a cationic nitrogen-containing functional group or cationic phosphorus-containing functional group. The invention also relates to a surface coating for products, containing the said butyl ion-containing polymer.
EFFECT: invention provides the effective reduction of the population size and/or prevention of accumulation of organisms on products.
28 cl, 1 dwg, 33 ex
FIELD: process engineering.
SUBSTANCE: invention relates to production of moulded articles containing polybutadiene and can be used in tire production as moulded strips for tire sidewalls or treads. Polybutadiene with content of cis-isomer over 95% and polydispersity lower than 2.5 is mixed with highly dispersed silicic acid and/or carbon black and with cross-linking agents, sulphur or sulphur donors, extra process additive and subjected to extrusion at 40-75°C.
EFFECT: higher quality of processing the mixes and quality of formed articles with lower rolling resistance and abrasion.
5 cl, 1 dwg, 2 tbl
SUBSTANCE: invention relates to thermoplastic moulding compounds. Described are thermoplastic moulding compounds, comprising: A) 10 to 98 wt % of a polyamide; B) 0.001 to 20 wt % of iron powder with particle size of at most 10 mcm (d50 value) and with a specific BET surface area of 0.1 to 5 m2/g according to DIN ISO 9277; C) 1 to 40 wt % of a halogen-free flame retardant from a group of the phosphorus- or nitrogen-containing compounds or P-N condensates, or a mixture thereof; and D) 0 to 70 wt % of other additives, where the total of the percentages by weight of components A) to D) is equal to 100%. The invention also describes use of said thermoplastic moulding compounds in making fibres, films and moulded articles, and fibres, films and moulded articles made from the thermoplastic moulding compounds.
EFFECT: providing thermoplastic polyamide moulding compounds, having improved heat aging resistance and good surface quality after heat aging, as well as mechanical properties.
10 cl, 3 tbl, 3 ex
SUBSTANCE: invention relates to a method of increasing homogeneity of mixtures of polyethylene, intended for manufacturing moulded products, films, tubes, wires and cables. A mixture of polyethylenes contains three fractures (A), (B) and (C) of a homo- or a copolymer of ethylene and at least one comonomer C3-C10 with different molecular weights. The low-molecular fraction A) has the weight-average molecular weight Mw lower than 40 kg/mol, the highly-molecular fraction B) has the molecular weight Mw higher than 250 kg/mol and the fraction C) has the intermediate molecular weight with the weight-average molecular weight Mw from 100 to 200 kg/mol. The mixture of polyethylenes has a single peak of melting as determined by means of differential scanning calorimetry (DSC).
EFFECT: obtained mixtures of polyethylenes, due to the improved homogeneity, possess improved properties, in particular surface properties, good processability and good mechanical properties.
16 cl, 9 dwg, 4 tbl, 3 ex
FIELD: process engineering.
SUBSTANCE: invention relates to production of sand blend or moulded article. Sand blend is composed on the mix of polyamide and master batch containing carbonic acid, particularly, with phenols or alcohols, and polyether amide. Polyamide has end groups, at least 50% of the latter are composed of end amine groups. Polyamide amount makes 10-99 wt %. Amount of polyether amide in master batch makes 1-90 wt %. Polyamide end groups, at least 50% thereof, are composed of end amine groups. This mix is stored and transported, if required. This mix is mixed in the melt at shear stress. Fused mix is unloaded and hardened to get sand batch of moulded article. Said moulded article represents a channel, plate or film.
EFFECT: produced article features higher content of end amino groups, higher resistance to hydrolysis.
FIELD: process engineering.
SUBSTANCE: invention relates to production of resilient noise-absorbing compositions based on polyurethanes and thermoplastic microspheres. Production of composition of polymer and powder filler comprises mixing of components, removal of gas inclusions and composition polymerization. Components are mixed in priming mould composed of hollow cylinder spinning about its axis. Power filler is composed of expanded microspheres used in amount of 1-2 wt % of composition weight.
EFFECT: accelerated removal of gas inclusions, decreased effects of lamination.
SUBSTANCE: invention relates to a composition, providing an active barrier for gaseous oxygen with short induction periods of oxygen absorption. The composition for a product with the reduced gas permeability contains a complex polyether, an ether and an ester copolymer and an oxidation catalyst, where the ether and the ester copolymer contains a zinc compound and at least one polyether unit, selected from the group, consisting of poly(tetramethylene ether) and poly(tetramethylene-co-alkylene ether), where the molecular weight of the said polyether unit is in the interval from approximately 200 g/mol to approximately 5000 g/mol and the said unit of polyether is present in a quantity from approximately 15 wt % to approximately 95 wt % of the said ether and ester copolymer. The invention additionally relates to the products, obtained from the composition, and the methods of obtaining the composition and products.
EFFECT: invention makes it possible to obtain the products, which have a short period of the oxygen absorption induction.
40 cl, 2 tbl
SUBSTANCE: in method realisation they clean a die of a future item, degrease it with subsequent application of separating wax and then a protective-finishing layer is applied - gel coat, with addition of current-conducting hydrocarbon fibres. Drying is carried out with subsequent hand moulding. Cut material is laid into the die, forming the item, then resin mixed with catalyst is applied, afterwards using brushes and/or soft rollers they evenly distribute the mixture along the die. The produced laminate is rolled with a stiff roller with its subsequent withdrawal from the mould and exposed to mechanical treatment.
EFFECT: production of items with low value of surface electric resistance and higher strength.
FIELD: process engineering.
SUBSTANCE: invention relates to production of plastic articles. Proposed method comprises the stages described below: extrusion of hose workpiece; melt flow separation inside extrusion die or cutting of extruded piece to obtain workpiece of approximately C-like shape and deformation of workpiece inside said die for blow moulding with application of pressure difference to hollow body. Proposed method differs from known processes in that, first, workpiece is expanded and pre-deformed in partially closed die. Then, at least one add-in part is arranged between parts of partially close die via workpiece open side inside said partially moulded article to close the die completely. Note here that said article of completely formed to obtain at least partially enveloping flattened seal. Mould closure is made in two steps. Note also that at first step, at least one plunger, preferably, several plungers fitted in die cavities make the front face parts of the die squeeze the workpiece to make at least one hole there between. Invention covers also the method of blow moulding.
EFFECT: lower costs, perfected configuration.
16 cl, 7 dwg
FIELD: machine building.
SUBSTANCE: proposed method comprises preparing binder directly before impregnation of fibrous filler. Epoxy-novolac binder with number-average molecular weight of 300 a.u. and weight fraction of epoxy groups of 8-11 are produced by loading 10-28 wt % of product into reactor, said product being obtained by epoxidation of hydroxyphenyl oligomer from alkyl resorcinol, 47-80 wt % of diane epoxy resin and 10-25 wt % of modifier, and by boiling at 60-250°C for 30-180 minutes. Article is shaped by drawing fibrous filler impregnated with binder and hardener via replacement die and helical winding on reinforcing bundle core.
EFFECT: higher physical and mechanical properties.
FIELD: process engineering.
SUBSTANCE: invention relates to machine building, particularly, to production of wear-resistant equipment with the use of polyurethane elastomers. In compliance with this method, structural elastomer parts are hardened by combining the elastic cold uniaxial deformation to 1-3% of initial size and mechanical fixture of geometrical sizes of elastically strained part. Hardening of said parts is ensured by their compression and highly elastic strain to 3-10% of initial sizes and retaining said part as-compressed. Fixture of the parts thus strained is ensured by the use of extra components, say, shells, cells, screw rods, stop plates of rigid polymers that prevent recovery of the part initial sizes.
EFFECT: hardening increased some 1,5-2,0 times.
3 cl, 7 dwg
FIELD: process engineering.
SUBSTANCE: flexible film sleeve 10 is cut in helix to flat strip by unwinding the film by rotary unwinder 1 on feeding flat film to sleeve expansion zone. Flat sleeve expands in said zone to round cylindrical sleeve to be passed axially above hollow mandrel 14 that feature OD slightly smaller than expanded sleeve diameter. Cutting is performed by knife 18 arranged at mandrel to flat strip moving off toward mandrel axis at an angle. Flat sleeve is stretched in lengthwise direction by tensioning tolls 107-112 revolving jointly with aforesaid unwinder. Besides, proposed device comprises stabilising means to stabilise orientation created by said tensioning rolls as applied to strip cut in helix after withdrawal from the mandrel.
EFFECT: higher film stabilisation, particularly, that thin laminar plastics.
22 cl, 3 dwg
SUBSTANCE: method consists in extrusion of lower, middle and upper films from according granules; thermal moulding of middle film having honeycomb structure; calibration and partial cooling of lower and upper films for their connection to middle film and further joining of these films. Device for production of web contains three extrusion heads, which produce extrusion unit. Then there is unit of middle film thermal moulding, units of upper and lower films calibration and cooling and cylinders of further heating of upper and lower films. Cylinders are installed upstream connection unit, where films are supplied from units of thermal moulding and units of calibration and cooling. Blister web is produced in a single production stage.
EFFECT: web has good physical and mechanical properties with no flaking and is used as element of protection or element of package.
19 cl, 3 dwg
FIELD: technological processes.
SUBSTANCE: invention is related to the field of plastic masses technology and method for making of art object from plastic mass. Hollow stock is pressure-moulded from transparent plastic masses on the basis of thermoplastic polymers. Twisted textile fibres coated with a layer of ceramic slurry and dried till moisture of not more than 5%, are attached to its internal walls, stock is heated till softening temperature, walls are applied one over another, then rolled and cooled.
EFFECT: simplified making of item from plastic mass with strictly fixed art composition.
FIELD: technological processes.
SUBSTANCE: invention is related to the field of plastic mixture technology and is related to method for production of art object from plastic mixture. Method includes pressure moulding of hollow blank from transparent plastic mixtures on the basis of thermoplastic polymers, its heating to softening temperature, rolling and cooling. Blank is heated to temperature that is less than its softening temperature by 10-30°C, afterwards internal surface of heated blank wall or its sections are metallised.
EFFECT: method provides for production of flat art object from plastic mixture with art composition of different colours.
FIELD: technological processes; textiles.
SUBSTANCE: hollow stock is molded under pressure from transparent plastic masses on the basis of thermoplastic polymers. In hollow stock pieces of woven and/or nonwoven, and/or knitted material are attached to its walls, on the basis of synthetic and/or wool fibers, stock is heated to softening temperature, at that walls are applied one onto another, then rolled and cooled. Prior to their fixing to wall of hollow stock pieces of woven and/or nonwoven, and/or knitted material are fixed to each other.
EFFECT: simplification of object production process from plastic mass with clearly fixed art composition.
2 cl, 1 ex
FIELD: technological processes.
SUBSTANCE: method includes pressurised molding of hollow billet from transparent plastic masses on the basis of thermoplastic polymers and installation in the billet and fixation to its walls of decorative elements made of coloured plastic masses on the basis of thermoplastic polymers. Then stock heating is done up to softening temperature with walls superposition one above another with further rolling and cooling.
EFFECT: prevention of decorative elements displacement.
FIELD: machine building.
SUBSTANCE: method of production of shaped article from unordered mat containing carbon fibre strands with mean length of fibre strands of 5-100 mm, and thermoplastic polymer. Said fibre strands are impregnated at heating and comprises of mat before or after placing in the mould. Production of definite unordered mat is executed by its impregnation with thermoplastic polymer, compaction of said mat in metal mould at 0.1-20 MPa and withdrawal unordered mat from metal mould. Large and complex shaped article is produced by moulding at low pressure in compliance with this invention.
EFFECT: simplified process.
13 cl, 5 dwg, 2 tbl, 7 ex