US 3696183 A
A process for producing a pile-surfaced article by pressing softened filament-forming thermoplastic polymeric material through a perforated web into contact with a heated surface to which the polymeric material sticks, parting the web and polymeric material from the heated surface so that filaments are produced and cooling the filaments to harden and disjoin them from the surface.
Description (OCR text may contain errors)
United States Patent Steel et a1.
 FORMING A PILE ON AN ARTICLE  Inventors: Margaret Lilian Steel; William Telford Cross, both of Runcom, En-
gland  Assignee: Imperial Chemical Industries Limited, London, England  Filed: Oct. 30, 1970 211 Appl. No.: 85,485
 Foreign Application Priority Data Oct. 30, 1969 Great Britain ..52,365/69  US. Cl. ..,..264/164, 161/62, 264/280, 264/284  Int. Cl ..B29c 17/02  Field of Search ..264/ 164, 280, 284, 293; 161/62  References Cited UNITED STATES PATENTS 3,390,403 6/1968 Tilburg ..264/284 X 51 Oct. 3, 1972 3,450,585 6/1969 Takagi ..264/164 X 3,230,134 l/1966 Studer ..264/174 X 3,179,550 4/1965 Friedman ..161/62 FOREIGN PATENTS OR APPLICATIONS 1,139,165 1/1969 Great Britain ..264/164 266,151 11/1961 Australia ..264/284 Primary Examiner-Robert F. White Assistant Examiner-Richard R. Kucia Attorney-Cushman, Darby & Cushman ABSTRACT A process for producing a pile-surfaced article by pressing softened filament-forming thermoplastic polymeric material through a perforated web into contact with a heated surface to which the polymeric material sticks, parting the web and polymeric material from the heated surface so that filaments are produced and cooling the filaments to harden and disjoin them from the surface.
19 Claims, 10 Drawing Figures PATENTED I973 v 3,696,183
' SHEET 1 0F 3 Attorneys PATENTED ET m2 3.696.183
' SHEET 3 BF 3 Wax/4M 721/25? [2 455 1 FORMING A PILE ON AN ARTICLE This invention relates to forming a pile on an article containing thermoplastic material, and to the pile-surfaced article thereby produced.
Many methods have been proposed for forming pile surfaces on thermoplastic articles. In accordance with one method, for example, the article is heated above the softening point of the polymer, pressed against a surface having a large number of e.g. conical depressions corresponding in density and shape with the protuberances required on the surface, and then parted from the surface. In a modification of this process, the depressions are so formed that the heads of the protuberances arelarger than their necks so that when the ar ticle is parted from the surface, the necks are stretched. While these processes can produce pile of useful and aesthetically attractive characteristics, the surfaces used in their production are expensive to make.
According to another more recently proposed process, thermoplastic polymer is pressed against a heated roller which'either has a smooth surface or has protuberances thereon and then the polymer is parted from the roller while cooling it below its softening point. The polymer sticks to the roller when it is pressed against it and the parting operation causes the formation and drawing of a large number of filaments which on cooling are broken away from the roller to form the pile surface. In our experience, we have found that while this process may operate successfully to start with, after a period of time the filaments tend to be replaced by small ridges running essentially longitudinally of the product. This defect cannot easily be corrected without stopping the machinery and starting afresh, and thus only short lengths of satisfactory product can be obtained.
According to the present invention we provide a process for producing a pile-surfaced article which comprises pressing softened filament-forming thermoplastic polymeric material through a porous or perforated web into contact with a surface heated to a temperature at which the polymer material will adhere to the surface, parting the web and the polymeric material from said surface to form filaments or tufts at points where the polymeric material has adhered to the surface and cooling the filaments or tufts whereby they are hardened and disjoined from said surface. For convenience the porous or perforated web will be referred to hereinafter as the perforated web.
Further according the the invention we provide a product comprising a perforated web having a backing of filament-forming thermoplastic material from which extend filamentary or tuft-like projections which extend through the web and proud of its top surface to give a pile-like effect.
By pressing the softened thermoplastic polymeric material through a perforated web the ridging associated with the above-mentioned previously proposed process may be reduced and generally avoided entirely without reverting to the use of costly equipment such as rollers with specially patterned or profiled surfaces. Moreover, a degree of control of the density of the fibrous or tufted surface is provided by use of the web since the number of filaments or tufts formed per unit area may be controlled by the number of pores or'perforations per unit area of the web. Yet
another advantage is that by means of the process, the thermoplastic material may be strongly bonded to the web, especially where it is a textile web, such that it is very difficult if not impossible to separate the one from theother in the finished article. A further advantage is that the product may be provided with a layer of thermoplastic polymeric material backing the web.
Examples of filament-forming thermoplastic polymeric material to which the process may be applied include addition polymers, for example polymers and copolymers from vinyl chloride, vinyl acetate, acrylonitrile, styrene, butadiene, vinylidene chloride, ethylene and propylene, and condensation polymers, for example polyarnide and polyesters, e.g. of glycols and aromatic dicarboxylic acids. Blends of fiber-forming thermoplastic polymer materials may also be used. The polymeric material is preferably used in the form of a sheet, such may be, for example, a continuous film or a perforated web. The thickness of the sheet is not critical although it will be recognized that generally the use of thicker sheets will yield heavier duty and more expensive products while the thinner ones will be lighter, cheaper and more flexible.
For use in the process, the thermoplastic material may be softened in any suitable manner such as by heat and/or by the action of plasticizers (e.g. as in vinyl plastisols) or solvents. For example, in thecase of heatsensitive polymers such as polyvinyl chloride, the polymer may be mixed with a non-polymeric compound, or mixture of non-polymeric compounds, which is solid at ambient temperatures and in which the polymer dissolved at elevated temperatures. Such a mixture will have softening properties different from those of the thermoplastic material itself, some further control of the process conditions being possible as a consequence.
Where the softening is to be effected partly or wholly by heat, at least some of the heat may be supplied to the polymeric material, for example, through contact with the surface and/or the web. However, because of the problems of heat transfer that are involved, it is generally preferred that at least some of the heat is supplied to the polymeric material by preheating. In one preferred embodiment, for example, the material may be supplied hot, e.g. in sheet form, by .melt extrusion and, provided the conditions are right, there may be no need for further heating. Alternatively it may be supplied e. g. from a roll of film and preheated.
The polymeric material may be supplied in a form other than sheet. For example, it may be supplied in the form of an external layer of a laminate: one outer layer of the laminate may comprise the filament-forming thermoplastic polymeric material while another layer may be, for example, of wear-resistant material, e.g. filled plastic or fabric-reinforced plastic. In yet a further alternative, the filament-forming thermoplastic polymeric material may be applied to the surface of the porous or perforated web in e.g. powder or granule form and then converted to a continuous or discontinuous backing layer by heating and rolling prior to, or possibly even simultaneously with, treatment by our process. In yet another alternative, it may be supplied in the form of a woven textile. In a further alternative, the material may be supplied in cellular or foamed form. The foamed or cellular material may be supplied in the form of a freshly extruded sheet or may be preformed and then softened, e. g. by heat.
The perforated web may be of any suitable material. Examples are woven and unwoven textile webs which may be of any desired material including metal, although where a synthetic material is used it may be preferred that it is not softened by the conditions to which it is exposed during the process. For close control of the texture of the pile formed by the process, it is generally preferable to use a woven textile, and it is not necessary that it be of fine weave or of particularly high strength material. For example, we have obtained satisfactory results with hessian, cotton net, glass fiber scrim, linen scrim and the like. If the web has too close a weave it may prove difficult to press the polymeric material through it unless the polymeric material has a low viscosity in the softened or molten state. The textile web may also be of paper or other material, e.g. metal or cardboard, having holes formed, e.g. punched, in it through which the thermoplastic polymeric material may be pushed in the process. It may also be expanded metal or expanded plastic, or extruded plastic net. Unwoven, unbonded webs can be used although care may be needed in pull-off until the thermoplastic has hardened sufficiently to act as an effective bonding agent.
The thermoplastic polymeric material may be combined with the web prior to contacting the heated surface, or simultaneously therewith, as desired. For ex ample a previously formed laminate of the perforated web and a web, sheet or film of the polymeric material may be contacted with the heated surface. Alternatively, the web and the polymeric material may be offerred separately to the heated surface.
The polymeric material may be pressed through the web into contact with the heated surface by a roller or any other suitable pressure-applying means, and the roller or other pressure-applying means is preferably at a temperature at which the polymeric material will not stick to it. The polymeric material pressed through the web and into contact with the heated surface adheres to it and, when the surface is parted from the web and material, filaments or tufts are formed at the points where the polymeric material has adhered to the surface. These filaments or tufts are then cooled whereby continuation of the parting action causes them to come away from the heated surface and form a hardened fibrous or tufted pile on the composite of web and polymeric material. If the filaments or tufts are not sufficiently cooled they tend to retract back into the web by the action of surface tension on parting from the heated surface.
The length of the filaments or tufts forming the pile depends upon the rate at which they are cooled, the temperature of the hot surface and the rate of parting of the web and polymeric material and the surface. The density of the pile (that is the number of filaments or tufts per unit area of surface) is controlled by the distribution pores or perforations in the web, e.g. the fineness of the weave of a textile material. The physical characteristics of the filaments or tufts depend upon the nature of the polymeric material and the degree to which the filaments or tufts are stretched during the process. Thus, by varying the choice of polymeric material or web and of the conditions operating during the process, products having a wide range of properties, texture and appearance may be obtained.
In accordance with another aspect of the present invention, the process of the invention is operated using at least two superimposed porous or perforated webs, the one nearer the heated surface preferably having a greater number of apertures per unit area than the other.
Thus, in the modified process softened filamentforming thermoplastic polymeric material is pressed through at least two superimposed perforated webs into contact with a surface heated to a temperature at which the polymeric material will adhere to it, parting the webs and polymeric material from said surface to form filaments, tufts or like protuberances at points where the polymeric material has adhered to the surface, and cooling the filaments, tufts or the like whereby they are disjoined from said surface and hardened.
Products formed by the modified process may subsequently be used to produce other textured materials having a lighter construction and handle than the original product. This is achieved by stripping the upper web or webs (i.e. the webs nearest the heated surface) from the composite product. When this is done, the stripped layer comprises one or more perforated webs having a textured polymeric surface on one face with a minimum of polymer on the reverse face. This stripping process is particularly advantageous when applied to products having two superimposed webs of woven material, the one which was nearest to the heated surface having a finer weave than the other. In this case the stripped layer can have a very fine texture, for example a velvet-like texture.
It will be appreciated that different surface effects may be produced by varying the nature of the perforated webs, their number and arrangement. It is possible to produce further modifications by also varying parameters such as the temperature of the heated surface, temperature, flow and disposition of the coolant fluid, as described above. It is also within the scope of this invention to interpose a non-stick backing surface between the cooler surface and the thermoplastic porous web sandwich.
The process of our invention is preferably operated continuously. For example the heated surface may be a moving surface, e.g. a roller or endless belt, which in combination with another moving surface, e.g. a backing roller or endless belt, forms a nip to which thermoplastic material and a porous or perforated web may be continuously supplied and from which the product may be continuously withdrawn.
Thus, in accordance with one embodiment of this aspect of the invention we provide machinery comprising a pair of contra-rotating rolls or endless belts forming between them a nip, means for driving the rolls or belts, means for supplying perforated web to the nip, an extruder for thermoplastic polymeric material arranged to supply extruded thermoplastic polymeric material in film or sheet form to the nip between one of the rolls (or belts) and the web, means for heating the roll or belt on the other side of the web to the thermoplastic polymeric material to a temperature at which the said material will adhere to the roll or belt, means for maintaining the other (or backing) roll or belt at a temperature below the softening point of the said thermoplastic polymeric material, and means for projecting a blast of cooling fluid into the out-running nip between the heated roll or belt and the exiting fused combination of web and polymeric material.
The invention is now described in more detail with reference to a number of alternative embodiments adapted for continuous operation and with the aid of the accompanying drawings in which FIG. 1 illustrates diagrammatically one embodiment of the invention adapted to continuous operation;
FIG. 2 is a cross-sectional representation of the product obtained by the process illustrated by FIG. 1;
FIG. 3 illustrates diagrammatically another embodiment of the invention whereby products with piles on two surfaces may be obtained;
FIG. 4 illustrates an alternative arrangement of the apparatus of FIG. 1 for use with thermoplastic polymeric material with a low viscosity in the melt and/or a sharp melting point;
FIGS. 5 and 6 illustrate modifications of the process introducing a second source of filament-forming synthetic thermoplastic polymeric material;
FIG. 7 is an isometric sketch of the product obtained by the embodiment illustrated in FIG. 5; and
FIG. 8 illustrates one of the sources of filament-forming thermoplastic polymeric material used in the production of the product illustrated in FIG. 7.
FIG. 9 shows diagrammatically part of the apparatus which may be used when a plurality of webs are employed, and FIG. 10 is a part view of FIG. 9 on an enlarged scale.
With reference to FIG. 1, 1 is a rolled up e.g. of perforated material, e. g. a textile, for example open-weave hessian, and 2 is the perforated web fed from the roll in the direction of the arrow to the nip between contrarotating rolls 3 and 4. The surface of the rolls 3 and 4 may be of metal if desired but it may be advantageous to use materials of lower thermal conductivity, e.g. stoneware, concrete or glass. The surfaces may be smooth but we do not exclude the use of surfaces that have been roughened, e.g. by abrasion, grinding, shotblasting or knurling. 5 is an extruder and 6 is a film or sheet of still hot, extruded, filament-forming thermoplastic polymeric material. The hot film preferably at a temperature above its softening point, is fed to the nip between the driven rolls and is separated from roll 3 by the porous or perforated web. Roll 3 is heated to a temperature at which the thermoplastic polymeric material will adhere to it, the heat being supplied, for example, by heating the interior with e.g. steam or hot oil in conventional manner. Backing roll 4 is maintained at a temperature below the softening point of the polymeric material and, if desired, contains cooling means e.g. a supply of fluid to the interior of the roll at a suitable temperature, to prevent the polymeric material sticking to it. 7 is a nozzle, slot or series of nozzles connected to a suitable supply by means not shown, for projecting a stream or streams of cooling fluid, suitably compressed air at ambient temperatures, into the out-running nip between the heated roll 3 and the outcoming composite of web and film, to cool the filaments or tufts formed on the exit side of the nip by the parting of the roll surface and the web and film. 8 is the pile-surfaced product exiting from the nip, which is wound up on the drum 9.
The temperature of the extruder die, the temperatures of the rolls and the temperature and pressure of the coolant fluid blast will depend upon the nature of the thermoplastic polymeric material used and the type of product e.g. length and density of the filaments or tufts forming the pile) required. For example, if the extruded film is too hot, it may sag although this may be avoided by extruding vertically downwards as described later. Again, at too high a temperature degradation of the thermoplastic may occur unless precautions are taken. For example, where aerial oxidation is likely the use of a cooling stream of an inert gas, for example nitrogen may be employed instead of air. On the other hand, if it is not hot enough, the film may be of poor quality or discontinuous in nature.
The temperature of the hot roll determines to a large extent the nature of the fibrous or tufted surface of the product. Thus, as the temperature of the roll is increased above that at which individual filaments or tufts are formed in substantially regular and dense fashion, more of the thermoplastic polymeric material tends to stick to it leading initially to the fusion of the tops of adjacent filaments or tufts and the subsequent production of a more or less continuous surface over irregular areas; and at very high temperatures, some of the thermoplastic polymeric material may remain stuck to the roll thus spoiling its surface. On the other hand, if the roll is too cool, the filament or tuft formation may become sparse and irregular. The temperature of the other (or backing) roll is less critical but has to be cool enough to prevent the film sticking but not so cool as to unduly increase the viscosity of the plastic and prevent its penetration of the textile web. In general, increasing the temperature of this other roll allows a larger proportion of the extrudate to be utilized in the filament formation with subsequent reduction of the relative thickness of the thermoplastic layer backing the textile in the formed product, with attendant economic advantage. The temperature of this roll is less critical if the thermoplastic polymeric material is supplied in cellular or foamed form the surface only whereof is heated, because of the insulation properties of the cellular or foamed material.
If no or insufficient fluid coolant blast is provided, those parts of the polymeric material which stick to the hot roll and draw into tufts or filaments may tend to subside back into the web on parting from the hot surface. By way of example, we have found that when using polyethylene as the thermoplastic polymeric material and a rate of production of about 4-5 inches per minute, preferred conditions are 210 to 220 C. in the extruder, to C., preferably 1 15 C. for the hot roll, 50 to 70 C. for the other (backing) roll, and compressed air at ambient temperature at about 40 lbs/sq.in. as the coolant blast. At increased linear throughput rates, somewhat higher temperatures may be required in the extruder and for the hot roll, together with a somewhat greater degree of cooling.
A cross-section of the product obtained by the process illustrated in FIG. 1 is shown in FIG. 2. It comprises a perforated web 2 (e.g. a textile web) having a backing of filament-forming thermoplastic polymeric material 6 from which extend filamentary or tuft-like projections 12, which extend through the textile web and proud of its top surface.
In accordance with another embodiment, illustrated in FIG. 3, a product having a pile on both surfaces may be obtained by supplying a further perforated web 2a from rolled up web stock la on the opposite side of the extruded film 6 from web 2, heating the backing roll 4 as well as roll 3 to cause the thermoplastic polymeric material to adhere to it, withdrawing the product from both rolls and providing for an additional coolant blast, e.g. by means of nozzle or nozzles 7a, between the roll 4 and the product 8a. For use in this modification, the thermoplastic polymeric material may be supplied, if desired, in the form of a laminate wherein both surfaces are formed of said material and the core, if any, may be of the same or a differential material. The product formed by use of this embodiment may, if desired, be slit along its thickness thereby providing two pile surfaced sheet products.
While the machinery embodiments illustrated in FIGS. 1 and 3 are satisfactory for many thermoplastic polymeric materials, in the case of those having a very sharp melting point and/or a relatively low viscosity in molten form, e.g. the crystalline polyamides and polyesters, it may be preferable to rearrange the apparatus so that the film of thermoplastic polymeric material is extruded downwards into the nip between the rolls 3 and 4. This may be achieved, for example, by in effect rotating the apparatus anticlockwise through a right angle, as illustrated in FIG. 4.
According to a modification of the process of the invention which allows for yet further variation of the product, a second filament-forming thermoplastic polymeric material is supplied either between the heated surface and the perforated web or between the web and the first filament-forming thermoplastic polymeric material. This second material is most preferably supplied in the form of a film and can be of the same or a different material to that of the first. In an alternative embodiment, and especially in the case where the second polymeric material is supplied between the web and the first polymeric material, the second may be provided in particulate form, if desired, e.g. by sprinkling powder or granules on to a film of the first material.
Where the second material is supplied between the heated surface and the web, for example, as illustrated in FIG. where a film 11 of filament-forming thermoplastic material is supplied from a storage roll 10, it appears that the first material is pressed through the web into contact with the film of second material which is softened either through contact with said first material or through contact with the heated roll, or both, and the second material adheres to the roll and provides the filaments or tufts on parting from the roll. Thus, in accordance with this modification, the invention comprises pressing softened filament-forming thermoplastic polymeric material through a porous or perforated web into contact with further filament-forming thermoplastic polymeric material which is provided on the other side of the web and contacting the second mentioned polymeric material with a surface heated to a temperature at which said second polymeric material will adhere to it, parting the web and first and second mentioned materials from said surface to form filaments or tufts at points where polymeric material has adhered to the surface, and cooling the filaments or tufts whereby they are disjoined from said surface and hardened.
By use of a second material having a different color to the first and by applying it in the form of a pattern, attractive multicolor patterned effects may be obtained. For example, products of the kind shown in FIG. 7 may be obtained by supplying the second material in the form of a film having the repeated pattern illustrated in FIG. 8. Moreover, the provision of the second material appears to improve the density of the pile.
Preferably this second material is preheated as a convenient additional means of supplying heat to the process. Thus, for example, it may be fed on to the heated roll 3 at a point well before the nip between rolls 3 and 4 so as to be preheated by contact with this roll, as illustrated in FIG. 5.
Where the second material is supplied between the web and first material, for example as illustrated in FIG. 6 where a film 14 of filament-forming material is supplied from a storage roll 13, it is believed that the first material softens the second material whereby a mixture of both is pressed through the web into contact with the heated roll. If desired, the film may be preheated before being fed to the nip.
In the case of both the above described alternatives, the second material may be supplied from an extruder, if desired.
Other alternatives to the machinery embodiments and the web and nature and method of delivery of the thermoplastic polymeric material will be apparent to those skilled in the art.
Depending upon the nature of the perforated web, the nature of the filament-forming thermoplastic polymeric material or materials, and the degree to which the filament or tufts are drawn, a wide variety of pile-surfaced products may be obtained which may be used in applications varying, for example, from artificial fur to artificial grass.
Still further variation may be obtained, for example, by providing for the heated surface to be embossed such that some parts of the surface are recessed compared to adjacent parts so that the thermoplastic polymeric materials fail to contact the recessed parts. In this way, products may be obtained in which a patterned pile effect is obtained. In a further alternative, the pressure and temperature of the coolant blast may be varied or it may be supplied intermittently rather than continuously thereby providing areas in the product where the top surface has a polished rather than pile effect. In yet a further alternative the heated surface may be regionally non-adhesive to the thermoplastic polymeric material so that filaments or tufts are not produced at such non-adhesive regions.
Referring now to FIG. 9. 15 is a roll of coarse-weave textile, e. g. a net of glass-fiber cotton, hessian, Terylene (Registered Trademark) or other suitable material, the net having a thread count of, for example, about 10 threads per inch. 16 is the textile web (hereinafter referred to as the primary web) being fed from the roll in the direction of the arrow.
17 is a roll of textile which is of finer weave that the primary web, e.g. having a thread count of from 20 to threads per inch, nylon and 18 is the web (hereinafter referred to as the secondary web) being fed from the roll in the direction of the arrow. Examples of suitable textiles for the secondary web or nylon and Terylene voiles.
The primary and secondary webs are fed into the nip between contra-rotating plain-surfaced rolls 19 and 20. The surfaces of the rolls may be of metal, if desired, but it may be advantageous to use materials of lower thermal conductivity. At least one of the rolls is power driven.
A film of heat-softened filament-forming thermoplastic material 2 is fed into the nip between the primary web 16 and the roll 19 from the slit die of an extruder 22.
The roll 20 is heated to a temperature at which the film 23 will adhere to it, roll 19 being maintained at a temperature below that at which the extruded thermoplastic material 21 will stick to it, but preferably as high a temperature as possible to reduce the temperature differential between the rolls. The temperatures of 20 the rolls will depend upon the nature of the thermoplastic material but where for example, the roll 20 may be at about 1 to 125 C. and roll 19 at about 90 C.
The textile webs and thermoplastic materials are drawn through the rolls by the rotation thereof and during their passage through the nip, the extruded thermoplastic material is forced through theweb into contact with roll 20. On issuing from the nip, the laminate as formed is drawn away from roll thus forming fibers, tufts or like protuberances 25 between the surface of the roll and the laminate and a blast of gas (e.g. compressed air) is directed at the fibers, tufts or the like from orifices 26 in supply tube 27 to cool and harden them, whereby they are broken away from the surface of the roll to provide a surface on the laminate. It is also believed that immediately on issuing from the nip, the secondary web is partly drawn away from the primary web, as indicated at 28 in the drawing, thus forming a filament-filled zone of weakness. Whether or not this is so, it has been found that the primary and secondary webs may be parted without difficulty on completion of thetreatment to provide two pile-surfaced products. That based on the secondary web may be of very fine texture having a medium of polymer on its reverse face. It resembles velvet and may be used, for example, as a furnishing'fabric, or for upholstery or curtains, for motor car interior linings, for clothing or as a wall-covering.
The secondary web may be a stretch fabric, e.g. a warp-knitted nylon monofil fabric of, for example, 1% to 2 ounces/yard, whereby simulated stretch velvet material may be produced.
Under carefully controlled conditions, the pile-surfaced products of our process may be shaped, e.g. by
vacuum forming. Care must be taken during the shap ing process, however, to avoid subjecting the products to conditions which would destroy the pile. By this means, for example, stair coverings preformed to the shape of the stairs may be obtained.
Applications for the products of our process include, for example, floor and ground coverings, e.g. in the place of carpets, for swimming pool surrounds, deck coverings for boats, indoor and outdoor tennis court surfaces, golf ranges, indoor and outdoor running tracks, bowling greens, ski and toboggan slopes, mats,
bathmats, bowling mats and curling mats; upholstery, e.g. for vehicles, deck chains, garden furniture, loose covers, cushion covers and antimacassars; linings e.g. for outer cold-weather garments, suitcases, cat and dog baskets, cutlery drawers, jewel cases and coffins; wall and ceiling coverings; card table tops; ornamental textured surfaces, e.g. for garments, millinery, footwear, shopping bags, handbags, sporrans, academic, clerical and civic regalia and stage scenery and costumes; simulated fur; sound-adsorbent articles, e.g. as buffers for lids and doors and as mats for typewriters, sewing machines, calculating machines, washing machines and dishwashers; conveyor belting, especially for retaining cylindrical or spherical objects; artificial surfaces for aquaria; supports for organisms in biochemical processes e. g. in water treatment; oyster beds; ski skins; polishing mats; filter media; towelling and paint stippling pads.
Soft easily flexible pile surfaced material produced by the method of the invention was found to be particularly useful in the manufacture of cheap disposable articles, including towelling (particularly when the web employed is a non-woven, bulky textile material) and clothing; it has been found effective, for example, in the production of disposable surgical wear, such as surgical gowns, hats, masks and overshoes.
The invention is further illustrated by the following Examples.
Polypropylene, nylon, polyethylene terephthalate (PET) and polyvinylchloride were treated according to the invention to produce a pile-surfaced article. The apparatus employed was substantially as described with reference to FIG. 4 of the drawings, the dimensions and mechanical specification being as follows:
The Extruder had a 1% inch, 24/1, L/D, Nylon type screw with four heater zones on the barrel and water cooled feed pocket. Variable speed drive from O to rpm. A nitrogen purged hopper was used with the nylon and PET.
Extrusion was through a slit die 10 inches long and 0.060 inches wide.
The Rolls were 7%. inches diameter and 15 inches wide, with variable speed drive giving surface speed range of 0.3 to 2.9 min. They were of roll material steel with smooth machined finish. Heating was by a stationary heater cage inside the rolls, temperature measurement being by contact type thermocouples mounted close to the roll surface.
The Air Blast was produced from a inch o.d. pipe with 3/64 inch holes, one-eighth inch apart.
Web Materials employed were as follows:
Fl. Cotton cloth woven 55 g/M 400 mesh/M.
F2. Glass fiber scrim 55 g/M 750 ends/M 620 picks/M plain weave.
F3. Hemp cloth Hemp filter cloth 600 g/M 400 mesh/M plain weave.
F4. Cotton Loomstate 100 g/M 2,400
ends/M 2,400 picks/ M.
F5. Linen scrim g/M 800 ends/M 800 picks/M.
Therrnoplastics employed were:
E1. Polypropylene lightly stabilized film type melt flow index 4.1-6.0.
E2. Nylon 66/610 copolymer high melt viscosity light temperature resistant.
E3. Nylon Maranyl type 66 extrusion grade. E4. PET Melinex fiber grade. E5. PVC Welvic.
Examples 11-17 were carried out using apparatus as shown in FIG. 6, with the exception of Example 14, for which apparatus as shown in FIG. 1 was used.
In each of the Examples 1 1-l 7, the thermoplastic material was low density polyethylene Alkathene (RTM) W.J.G. l I (either as chip fed to the extender of as film of the appropriate thickness).
In the Examples the extruder die lip to roll nip distance was inches, the coolant jet to roll nip distance was 1 inch and the coolant air pressure was 50 lb/sq.in. g.
In a further Example (18) of the process of the invention a product having pile on both surfaces was obtained using apparatus substantially as illustrated in FIG. 3, except that the polymer (Alkathene) was fed to the nip as a preformed film 0.004 inch thick instead of as a direct extrudate. Terylene voile as in Examples ll-l4 was used as the webs and operating conditions were generally as described for those Examples, except that both rolls were at the same temperature of 1 15 C.
The product obtained in Example 18 could be divided by pulling apart the two component webs to give two layers of a soft product each having pile on one surface only.
Extru ther- Hot cold der mop- Roll Roll roll roll Sp- Band Die [85- speed force temp temp eed Temp. Temp. ex. web tic ft/min lb C C rpm C C 1 F, E 0.415 1400 205 55 150/200 220 2 F, E, 0.5 700- 250 90 20 220/230 220/230 1400 3 F, E, 0.6 1400 185 85 40 225/245 227/230 4 F, E, 1.1 1400 260 90 18 220/230 226/228 5 F. E, 1.0 1400 205 95 18.5 220/240 225/230 6 F E, 0.9 1400190 90 26 225/235 228/230 7 F, E; 0.8 1400 290 85 16 280/295 291/292 8 F, E, 0.9 700 230 70 21 280/300 284/287 9 F 13 2.85 700- 285 90 50 290/300 285/288 Thickness of Roll Hot Cold polythene film speed Roll Roll Roll Die (2nd filamenth/ force temp temp temp forming ex. Web min. lb. C C C material) Mono- 1] filament 0.5 1400 100-12080-90 200 0.001"-0.003" l2 terylene' 0.5 1400 110-12080-90 200 0.0010.003" l3 voile-70 0.5 1400 110-12080-90 200 0001 -0003" 14 ends/in 0.5 1400 110-12080-90 200 None (EFl) 70 picks /in(PPl) 15 1S mesh/in 0.5 1400 110-12080-90 200 0.003"0.005" 16 warp knit 0.5 1400 110-12080-90 200 0.003"0.005"
terylene' net 17 Hessian 0.5 1400 110-1260-90 200 0.003"-0.015"
cloth l0 mesh/in We claim:
1. A process for producing a pile surfaced article 6s 12 which comprises pressing softened filament forming thermo lastic l eric material throu a rforated web int?) cont vin th a surface heate to fiemperature at which the polymer material will adhere to the surface, parting the web and the polymeric material from said surface to form projections at points where the polymeric material has adhered to the surface and cooling the projections whereby they are hardened and disjoined from said surface.
2. A process according to claim 1, in which softening of the thermoplastic polymeric material is effected by heat.
3. A process according to claim 1 in which the thermoplastic polymeric material is supplied to the perforated web in the form of a sheet.
4. A process according to claim 1 in which the thermoplastic polymeric material is a polyolefin.
5. A process according to claim 4 in which the thermoplastic polymeric material is selected from the group consisting of polyethylene and polypropylene.
6. A process according to claim 1 in which the thermoplastic polymeric material is a polyamide.
7. A process according to claim 1 in which the thermoplastic polymeric material is polyvinyl chloride.
8. A process according to claim 1, in which the thermoplastic polymeric material is a condensation product of a glycol and an aromatic dicarboxylic acid.
9. A process according to claim 8 in which the thermoplastic polymeric material is polyethylene terephthalate.
10. A process according to claim 1 in which cooling of the projections to harden and disjoin them from the heated surface is effected by means of a stream of cold gas.
11. A process according to claim 10 in which the gas is air.
12. A process according to claim 1 in which the softened thermoplastic polymeric material is pressed through a second perforated web prior to contacting the heated surface, the second web subsequently being stripped from the composite product.
13. A process according to claim 1 in which the perforated web is a woven textile material.
14. A process according to claim 1 in which the web is a non-woven material.
15. A process according to claim 1 in which the heated surface against which the thermoplastic polymeric material is pressed forms part of the cylindrical surface of a roller.
16. A process according to claim 1 in which pressure to press the thermoplastic polymeric material through the web is applied by means of a roller.
17. A process according to claim 1 in which a second thermoplastic polymeric material is supplied between the heated surface and the perforated web.
18. A process according to claim 1 in which a second thermoplastic polymeric material is supplied between the perforated web and the first thermoplastic polymeric material.
19. A process according to claim 1 in which the heated surface is rendered regionally non-adhesive to the thermoplastic polymeric material, whereby a patterned pile effect is obtained in the product.
* l *1 III