DK141445B - Process for producing a sheet or web-shaped material with plywood and apparatus for carrying out the method. - Google Patents

Description

(§) (11) PUBLICATION 141445 DENMARK («) lnt.CI. = D 04 H 11700 § (21) Application No. 2293/77 (22) Filed on 25« m8.j 1977 (23) Life day 19-Nov. 1971 (44) The application presented and

submitted thesis statement offtwiLs made on 17 · © Si ?. 1 QUO

DIRECTORATE OF THE _ PATENT AND TRADEMARKET (30) Priority begwet from the 'ten'

20 nov. 1970, 55241/70, GB

20 nov. 1970, 55242/70, GB Dec 24 1970, 61326/70, GB Dec 24 1970, 61325/70, GB

(71) IMPERIAL CHEMICAL INDUSTRIES LIMITED, Thames House North, Millbank,

Hendon SW1P 4QG, GB.

(72) Inventor: Margaret Lilian Steel, Petrochemical & Polymer Laboratory,

The Heath, Runcorn, Cheshire, GB: William Telford Cross, Petrochemical & Polymer Laboratory, The Heath, Runcorn, Cheshire, GB: Stephen Edward Trueman, Petrochemical & Polymer Laboratory, The Heath, Run * corn, Cheshire, GB: David Malcolm Fisher , Petrochemical & Polymer La = boratory, The Heath, Runcorn, Cheshire, GB: Donald John Bye, Petrochemical & Polymer Laboratory, The Heath, Runcorn, Cheshire, GB: Glynn Arthur Wardle, Petrochemical & Polymer Laboratory, The Heath, Runcorn, Cheshire , GB: Barbara Job, Petrochemical & Polymer Laboratory, The Heath, Runcorn, Cheshire, GB.

(74) Fully accomplished during blessing treatment:

The company Chas. Hude.

(54) Process for producing a sheet or web-shaped material with plywood and apparatus for carrying out the process.

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a method for producing a sheet or web-shaped material having plywood, wherein a method of forming fibrous thermoplastic material is introduced between a carrier web and a heated roller, and the carrier web is pressed against the thermoplastic material to bond to the carrier web and adhere to the surface of the heated roller, wherein the thermoplastic material is separated from the surface of the heated roller to form fibers or tufts between the carrier web and the heated roller, after which the fibers or tufts thus formed are cured by a stream of refrigerant and detached from the heated roller.

From the specification of Danish Patent No. 119-077 there is known a method in which the fiber-forming material is passed through a roller slot "UU40 2" between two conveyor belts, one of which supports the fiber-forming material and the other is heated by a hot roll forming hot surface to which the fibers temporarily adhere. The conveyor belts leave the roll tangentially and remove from each other, thereby loosening the fiber-forming material from one belt to gain fiber formation.

In the space between the divergent bands, cooling air is blown in to induce curing of the fibers upon tearing from one band. In this process there is a risk that the product will have an irregular surface, since the slit or wedge-shaped outlet opening in which the cooling air is blown in is very narrow and the cooling air cannot flow undisturbed.

SUMMARY OF THE INVENTION It is an object of the invention to provide a method of the kind in which by means of which a regular air surface can be obtained with greater certainty than before, the use of cooling with air or other gas can be obtained.

The method according to the invention is characterized in that the flow of refrigerant is directed to the side of the carrier which faces away from the heated roller and that the fibrous material is cooled before the fibers have detached from the heated surface.

In a porous support air, the air can flow through the material, thereby not only cooling better, but also flowing more evenly, and regardless of whether a greater or lesser amount of cooling air penetrates the carrier, it is advantageous that the air flow and air fibers during formation do not mutually influence each other mechanically, whereby the direction of air flow towards and cooling of the carrier web with the pile fibers can be controlled with great certainty, which is important for determining the place where the pile fibers should release the heated surface or in other words for the nature of the pile formed. Controlling the degree of cooling is also important because the fibers, if insufficiently cooled, tend to retreat into the fabric as they are detached from the heated surface.

The amount and shape of the fibers forming the pulp is influenced by the rate at which it cools and cures, and by the temperature of the hot surface and the rate at which the carrier web of the fibrous material is separated from the surface. The mechanical properties of the plywood fibers are influenced by the nature of the fiber-forming thermoplastic material and the degree of stretching of the plywood fibers during forming. By varying the choice of polymer mass and carrier web and the working conditions of the manufacture, * products with varying properties, texture and appearance can be produced. It has been found particularly advantageous to accelerate the cooling of the pulp fibers during their pull-up by a stream of refrigerant, preferably eix gas, e.g., atmospheric air, or an inert gas such as nitrogen in cases where air oxidation may cause difficulties.

The nature of the final product depends to a large extent on the temperature of the pulled fiber forming polymer at the time it is separated from the heated surface. Thus, the degree of retraction of the fibers can affect the temperature of the detachment site, which is, of course, dependent on the temperature of the heated surface and the temperature, flow rate and direction of the refrigerant used. The flow of the refrigerant can be varied in the width direction of the web and possibly vary with time, increasing the flow rate decreases the length of the plywood and vice versa. The distance between the place where the fibers are produced and the means for supplying refrigerant can be varied in the transverse direction over the width of the product and / or with time. Thus, changing this distance may e.g. used to change the nature of the fibers, especially their degree of curl. The temperature of the refrigerant (especially at the site where the fibers are formed) may be varied in the transverse direction of the male and possibly varied with time, and the means for supplying the refrigerant may include a number of openings or a slit-shaped nozzle extending across the material web. The effect produced by any of these variables can be modified by other factors such as the direction of the nozzle gap or openings and their distance from the site where the pile fibers form '. Usually, if desired, a number of nozzle openings can be used to form products with regular height variations of the pile in the transverse direction of the product.

In many cases, it is preferable to select a particular combination of refrigerant and other parameters and to run the process until sustained or stable characteristics of the product are obtained. However, it will be appreciated that all the parameters can be varied in a cyclic manner to obtain patterned or other disparate effects. The speed and angle at which the product is pulled as well as the tension in the product can also affect the nature of the surface structure.

4 U1445

The method according to the invention can be carried out on an apparatus having a smooth or rough surface roller, heating means for heating the roller, means for applying and pressing a web of fibrous material and a support web against the heated roller, means for guiding the material and the carrier web, respectively, to and from the heated roller and means for directing a flow of refrigerant to the assembly of carrier web and fiber-forming material, and this apparatus is characterized in that the cooling means are disposed at the away side of the heated roller facing side of the carrier web. in such a way that a flow of refrigerant can be directed into the area where the fibers are detached from the surface of the roll.

As mentioned, the cooling must be effected by a flow of a fluid, preferably gas and especially air or nitrogen, at a temperature below that of the carrier. It has been found convenient that compressed air at ambient temperature or colder and with a pressure between 0.70 kg / cm and 4.22 kg / cm, preferably between 1.4 and 2.11 kg / cm, is suitable. such as cooling air flow. The apparatus for carrying out the method may further be provided with a tube of well-conducting material, e.g. copper through which a refrigerant flows, e.g. water or another liquid or gas. The temperature of the refrigerant is chosen such that the desired cooling of the carrier web is obtained, taking into account the material used, the thickness of the carrier web, the feed rate, etc.

The cooling is performed for a sufficiently long period of time before the fibers detach from the heated surface to prevent them from completely contracting, so that the pavement effect is lost. The temperature of the cooling means depends on the temperature reduction of the product to be obtained, and furthermore, the materials used and the temperature of the heated surface must be taken into account as well as the thickness of the carrier web and the polymeric material, the feed rate of the carrier web and similar factors.

The invention will be explained in greater detail in the following with reference to the drawing, which schematically shows a side view of an embodiment of an apparatus for carrying out the method according to the invention in a continuous process and during cooling of the side of the carrier path away from the heated roller.

In the drawing, reference numeral 1 denotes a carrier path e.g. of textile material such as "Terylene" -voile, and 2 is a film of thermoplastic polymer mass which is inserted into a gap between two opposite continuous rollers 3 and 4. The surface of the rollers may or may not be of metal, but it may be advantageous to use other materials with lower thermal conductivity, e.g. stoneware, ceramics, concrete or glass. The surface may be smooth, but surfaces that have been roughened, e.g. by grinding (e.g. to produce a "satin" effect), scouring, sandblasting or rifling. The film 2, which is optionally preheated to a suitable temperature above the softening point, is fed to the gap between the rollers, at least one of which is driven, and it is separated from the roll 4 by the carrier web 1. The roll 3 is heated to a temperature at which the thermoplastic polymeric material will adhere to it, the heat being applied e.g. by heating the interior, e.g. with electricity or hot oil in the usual manner. The roll 4 has a resilient resilient surface and is preferably kept at a temperature below the softening point of the thermoplastic material and if desired contains cooling means, e.g. means for supplying liquid or gas to the interior of the roller at an appropriate temperature to prevent plastic material from adhering to the surface. Use of a non-adhesive coating on the surface of the roller 4, e.g. a thin layer of PTFE or silicone may be desirable. 5 is a nozzle, a tube with slits or a series of nozzles from which a stream of refrigerant, preferably compressed air, can be emitted into the side of the carrier web facing away from the pavement surface. The cooling effect is increased when the carrier web is porous, so that the air through the carrier web can penetrate the fiber layer to cool the carrier web and the pile fibers in a location before the fibers are released from the heated surface. A pile surface product leaving the roller slot is designated by reference numeral 6.

The temperature at which the polymeric material is preheated (if preheating is used) and the temperature of the rollers as well as the temperature and pressure of the coolant flow through the nozzle 5 are selected for the nature of the thermoplastic material used and the type of product required (e.g. length and density of the pile fibers). If the material e.g. is thermoplastic, and it is too hot, it can hang in an arc, although this can be avoided by adding it vertically to the slit. Thermoplastic degradation can also occur at too high a temperature, unless precautions are taken. Where air oxidation can occur, cooling is used with an inert gas, e.g. nitrogen, helium or carbon dioxide instead of air, and when highly oxygen sensitive polymers are used, coverage using nitrogen or another suitable inert gas may be necessary. If the film is not hot enough, the cap may be of poor quality or of a discontinuous nature.

The temperature of the hot surface affects the nature of the plywood fiber surface of the product. For example, if the movie 2. is a thermoplastic polymer, and the temperature of the heated roller exceeds the temperature at which individual fibers are formed, more of the thermoplastic polymeric material tends to adhere to the surface, which first leads to melting of the peaks adjacent to each other. pulp fibers and then to form a more or less continuous surface over irregular areas, and at very high temperatures some of the thermoplastic polymeric material may continue to adhere to the roller, thus destroying its surface. On the other hand, if the roller 3 is too cold, the plywood fiber formation can become sparse and irregular.

The temperature of the roller is less critical, but it must either be cold enough to prevent the material from adhering to it, but not so cold as to unreasonably increase the viscosity of the plastic and impede its penetration into the carrier web, or it must be rendered non-sticky being either inherently non-adhesive material or has a non-adhesive coating, e.g. "Fluon" ® or a silicone.

Optionally, the cooling of the support web on the underside can be supplemented with other cooling, so that the support web with the peat-forming thermoplastic material is cooled both on the front and the back. The side of the carrier web facing away from the pavement surface can be further cooled by contacting it with a tube through which a refrigerant is conducted. The tube is arranged perpendicular to the direction of movement of the web and parallel to the axis of the roller 3 »

Fiber-forming thermoplastic polymers which can be used in the process of the invention include addition polymers, e.g.

141445 polymers and copolymers of ethylene, propylene, butadiene, vinyl chloride, vinyl acetate, vinylidene chloride, acrylonitrile and styrene and polymer-dense polymers e.g. polyamides and polyesters, e.g. of glycols and aromatic dicarboxylic acids. Mixtures of fiber-forming polymers can be used.

As particular examples of thermoplastic polymers which can be used to make the peat materials are polyethylene, poly propylene, nylon, polyethylene terephthalate and polyvinyl chloride. The thickness of the sheet is not critical.

Other thermoplastic materials which can be used in the process of the invention are glass, in particular low melting inorganic glass.

The carrier web may be of natural or synthetic material. Eg. can be used regenerated cellulose. Synthetic materials from which the web can be made include, for example, those described above as being useful as fiber forming material. Of course, it is important that there is at least sufficient bonding between the fiber-forming material and the carrier web to prevent them from being separated when the fibers are separated from the heated surface, and although this can be done without special pre-treatment of the carrier web, some treating its surface may be advantageous, e.g. a suitable plasticizer or solvent may be applied. It is often advantageous to use a woven fabric as a carrier. For example, satisfactory results have been achieved with hessian, cotton nets, fiberglass canvas and flax canvas. The carrier web may also be of other material, e.g. perforated metal, cardboard or paper. It can also be of expanded metal, expanded plastic or extruded a plastic mesh. Plastic foam sheets, e.g. of polyurethane, has obtained peat surface using relatively thin (e.g. 1-5 mm thick) foam with open cells, but much thicker foam can also be used.

Example

The apparatus shown in the drawing was used to prepare a pile surface product according to the invention. The carrier web was ® 2 woven "Terrylene * ** (30 g / m) with perforations with 2 mm side length. The thermoplastic material was a web of low weight polyethylene (" Alkathene "®) with a thickness of 0.05 mm. The roller 3 was heated