DE831311C - Method for covering material webs or the like with linear polymeric plastics - Google Patents

Description

(WiGBl. P. 175)

ISSUED FEBRUARY 11, 1952

P 1046 XII / 39 a

(V. St. A.)

V-.

The invention relates to a method for applying a film of a synthetic linear polymer with a pronounced sharp melting point to a fibrous web, such as / .. as paper, Gewel> e or metal foil ο. like

Various methods of applying thin films of thermoplastic polymeric plastics to webs of paper have been used. Corrugations ?, metal foils or the like. Proposed. Many of these known methods have one or more disadvantages, or the properties of the paved edges or webs are not satisfactory from the standpoint of commercial utility. For example, it is difficult to apply thin amounts of Athyk'tipolymers or polyamides by hot melting due to their high melt viscosities and their poor stability at the melting temperatures. In addition, poor adhesion of the covering to the base material can be observed with this type of production. In other cases, calenders were used to increase the pressure and thereby improve the adhesion between the polymer and the fabric web. Such a device is, however, rather expensive ¹ , and with it, too, the desired results cannot be achieved with all polymers of the type to be described, for example polyamides become too high at the high temperatures required for calendering

easily oxidized. Another suggestion for improvement the bond between the polymer covering and the fibrous webs o. The like. Consists in the use of adhesives, but these products also have various disadvantages, since the properties of the adhesive are seldom equivalent to and of the polymer are often inferior, especially when the polymer is for a particular application ίο is selected.

There has been a method of making ethylene polymer coverings on materials described in which a layer of molten polymer is applied to a metal surface is, for example, on the surface of a metal cylinder or on a continuous metal belt, the surface of the material to be coated against the layer of the molten one The polymer is pressed and the polymer is cooled until it is in contact with the metal surface Contacting surface has become solid, whereupon the covered material from the surface Will get removed.

The invention now proposes an economic Ii this method of applying films linear polymer plastics with a sharp melting point on material webs. A The advantage of the invention is that there is an intimate connection between the film and the base material can be achieved without the need for an intermediate layer of adhesive. A Another feature of the invention is seen in a method for applying films made of solid ethylene polymers, chlorinated solid ethylene polymers and polyamides on sheets of paper, fabric or metal foils is suggested. Further features of the invention result from the following description.

The method which is the subject of the invention is that a molten film a usually solid linear polymeric plastic with a sharp melting point with the material web to be covered is brought into contact, the molten film against the base material is pressed and the free surface of the molten film quickly on a tempering apparatus is cooled below the solidification point.

The method forming the subject of the invention can be carried out using any of known mechanical means can be carried out. It is preferred to have the polymer film on top to apply the material web in that the web in the gap between two adjacent parallel rollers are introduced, which rotate in opposite directions of rotation, wherein the molten film of the polymer parallel to the rollers perpendicularly down into the nip is pressed out, whereupon the film and the base material through the gap between the rollers go through and be pressurized there. The roller which is in contact with the film is maintained at a temperature below the solidification point of the molten film.

In the drawing is an arrangement of an apparatus for carrying out the the object of the invention forming method shown.

In this apparatus, the polymer is passed through a nozzle 2 by means of a conventional extruder 1 which is provided with a narrow slit opening, whereby a molten film 3 is formed. A pair of adjacent parallel rollers 4 and 5, which rotate in opposite directions circulate, lie below the nozzle 2, so that the molten film 3 is a short piece in the runs essentially vertically downwards before it reaches the gap 6 between the rollers.

The material web 7 to which the film is to be applied runs from a supply roll 8 and partially wraps around the roller 4 before it enters the gap 6 between the rollers. the The material web and the film come into contact with one another in the nip of the rolls, i.e. H. she are not brought into contact much before this point, and the film 3 also gets not in contact with the roller 5. the gap 6 between the rollers. If so then the one Film 3 and web 7 touch each other, they are pressed against each other, and the free surface of the film 3, the other surface rests against the web 7, is rapidly cooled by the roller 5, all of these operations being essentially simultaneous.

The nozzle 2 is designed such that the distance between it and the gap 6 is proportionate is short. With this arrangement, the temperature of the film 3 practically changes when it reaches the gap 6, not compared to the temperature at which it leaves the nozzle 2. The polymer is heated in the extruder 1 to a temperature which is considerably above that which the film has when it reaches the gap 6, so that there is a greater distance between the Nozzle 2 and the gap 6 is possible, since a certain cooling of the film is permitted here. i The same result can be obtained if: means for heating, or for preventing the j Cooling of the film during its transition from the nozzle 2 to the gap 6 are provided; However none of these modifications is as practical as simply placing the nozzle 2 close to the Gap 6 is brought about in the manner shown in the drawing.

The material web 7 and the film 3 run a little around the roller 5 and reach one Roller 9, over which they are passed, whereupon the material provided with the covering on a Collecting roller 11 is wound up to form the bobbin.

The roller 4 can, if desired, be provided with steam coils o Preheat material web 7; the roller 5 is expediently provided with a cold water circulation, in order to keep the temperature of this roller below the solidification point of the film 3. if the roller 4 is not to be heated, so needs

the YVcik> tor'fbahii 7 also not about them and partially around it, and in this case the web can be fed directly into the gap 6 without first coming into contact with the roller 4. The one on the The apparatus shown in the drawing has proven to be particularly useful, regardless of whether the Roller 4 is heated or not.

Although in the method according to the invention by no means a pressure is exerted as in the calenders, which is an essential advantage, between the rolls 4 and 5 there is a certain advantage Pressure is exerted on the sheet of material and the film as they pass through the gap. This can expediently take place in that one of the two rollers is eccentrically mounted and a friction clutch is used, although others, of course, are also used usual means for this purpose can be used. The pressure can be increased by changing the The distance between the rollers 4 and 5 can be regulated from one another. In general it can be stated that that the greater the pressure exerted by these rollers on the material web and the film the stronger the connection between the two is, although it is not necessary to apply a pressure of the order of magnitude that is usually the case when working with calender rolls is exercised. At least one of the two rollers 4 and 5 is driven, of course both can also be driven; in the latter case it is not absolutely necessary that they rotate at the same peripheral speed.

The roller 5 should be provided with a non-compressible surface. Usually a metal roller is used, and the surface thereof can be smooth or with a Surface effect be provided, in which case a corresponding roughened surface of the Topping is obtained. The surface of the roller 5 can also be made of metal or some other non-compressible Consist of fabric; however, it is preferably made of a compressible material; a squeegee has turned up for proved particularly suitable for this purpose.

The thickness of the film can be adjusted by adjusting it any of the following, or a combination of these, can be easily changed:

by changing the nozzle opening and the screw speed in the extrusion press, by changing the discharge speed of the | documented material, by changing the material used by the j Rollers 4 and 5 or pressure exerted by the roller 9. The pressure exerted by the rollers 4 and 5 is applied to the nip 6 can be regulated by changing the spacing of these rollers will.

The temperature of the molten film when it comes into contact with the material web can increase any point between the melting point of the polymer to its decomposition j temperature, but each polymer j has a particularly useful temperature range, ; which is well above the melting point at which the process works best and with the best results in terms of the adhesion of the film to the base material, the Uniformity of the film and the quality of the film surface can be achieved. During execution these best running processes constitute these particular temperature ranges for films Various polymers are extremely important factors when establishing a solid bond between the film and the base material should graze. In those cases where such a permanent connection is insignificant or actually not desired, for example in the case where the film is from the base material is to be peeled off, and usually a smooth surface The material used is the application of these special temperature ranges irrelevant, and usually work is carried out at lower temperatures, below which the film has melted.

The film can be heated to any temperature below the solidification point of the molten one The film needs to be cooled quickly. The temperature of the material web at the point of contact with the film is not of particular concern, as is the pressure that is used to compress it of the material with the film is used, although the adhesion of the film to the base material is somewhat improved when the Pressure is increased.

The polymers used in the process according to the invention have a linear molecular structure in contrast to polymers which have a three-dimensional network of chemical bonds which makes it impossible to dissolve these polymers and to change their shape by the application of heat. These polymers can be processed into fiber materials by cold drawing, which have a certain degree of microcrystalline structure in the X-ray examination and are oriented along the fiber axis. These polymers have to resemble liquids in the molten state the property, they ie have relatively sharp melting points, and they are ¹ only in a very limited temperature range, somewhat plastic. If this is exceeded, they immediately become free-flowing liquids.

Preferably the film consists of a polymer selected from the group consisting of the ethylene polymers, chlorinated Ethylene polymers, which preferably have a chlorine content of 20 to 40%, and polyamides contains, for example, polyhexamethylene adipamide.

When ethylene polymers, the temperature of the molten film in contact with the web of material between 120 and 300 ⁰ C and preferably 220 to 260 ⁰ C may be, and the film is rapidly cooled to a temperature vorziugsweise between 45 and 65 ° C. In the case of chlorinated ethylene polymers, the

molten film at a temperature preferably between 135 and 16o ° C when using is in contact with the foreign material. The same cooling temperatures are found here Use.

When a polyamide film is used, it can be processed at a temperature between the Schynelzpunkt of the polyamide and 300 ⁰ C, preferably not above 275 ⁰ C. The PoIyamide can be Möhr or less sharply in those having a relatively high melting point and those with relatively low Subdivide melting point. With regard to the former, it is preferred that the film ^{contact the base material at a temperature of at least 235 °} C., while a lower temperature of 190 ^° C. is used for the latter. In the case of all the polyamides of the film 10 should be cooled to 120 ⁰ C, with a limited range between 20 and ioo ° C is preferred.

Other polymers which are suitable for the method according to the invention are polyesters, Polyester amides, polyanhydrides and polyethers. Mixtures of two or more polymers can also be used and interpolymers can be used as the film material provided that they are essential Have properties of usually being solid, thermoplastic materials (linear polymers) and have sufficiently sharp melting points. The polymer film can contain small amounts of the usual additives, such as plasticizers, fillers and dyes, Opaque agents, heat and light stabilizers, anti-aging agents, metallic ones Retarders and lubricants.

The method forming the subject of the invention is to the greatest extent possible on material webs generally applicable. It is particularly useful for making coatings on Fibrous materials such as paper, wood veneer, or woven or knitted fabric sheets, which are made from fibrous materials made from natural or regenerated cellulose, Rayon, polyamides, cellulose derivatives, synthetic resins, asbestos or glass as well non-fibrous materials such as regenerated cellulose, metal foil and thermoplastic sheets Films, exist. The strength of these webs is not of particular concern as they are made of pliable Silky papers can vary to solid metal sheets, though the greatest advantages can be achieved when the invention is applied to flexible webs of material which can be rolled up on a roller.

The temperature of the material web can increase within it when it comes into contact with the film Change boundaries. A temperature of 100 to 120 ° C is preferred because this causes the bond between the film and the base material is improved, but is generally by preheating does not provide any particular benefit. It has been observed that although it is necessary.

the melted film to a temperature to cool below its solidification point, the higher the cooling temperature used the better the bond between the base material and the film, without special adhesives are applied or a special amount of pressure between Base layer and film takes place. So it will be with the highest possible cooling temperature worked, the sticking of the film to the apparatus is just prevented.

The following examples are some exemplary embodiments indicated in the explanation, but this is not restricted to this.

example 1

Ethylene polymer with an average molecular weight of 18,000 to 20,000, which contains 0.2% N ₁ N'-diphenyl-p-phenylenediamine as an anti-aging agent, is introduced into an extruder which has a slot-like outlet opening of 0.127 mm '. The temperature of the mouthpiece is kept between 250 and 300 ^° C. during the pressing out. The pressed, molten film is fed to the gap between two rotating rollers via an air space of 82.6 mm, as can be seen from the drawing.

The roller 5 consists of a polished steel roller with a core and approximately 89 mm in diameter, the surface of which is cooled ^{to a temperature of approximately 50 ° C. by circulating cold water inside.} The roller 4 l> consists of a rubber roller 7 ° mm in diameter. This roller is at room temperature and it is driven by friction and rests in an eccentric bearing, whereby various 1 °° pressures can be exerted. The molten film comes into contact with a paper web about 0.127 ^mm thick in the gap between the two rollers. The take-off speed of the paper provided with the film material was changed up to 18 m per minute and the pressure between the rollers was also adjusted so that the thickness of the ethylene polymer coating was 0.018 mm. It was thus obtained on the paper web in a well-adhering, smooth, even Beno lay made of ethylene polymer 0.018 mm thick and the paper web was pulled off at a speed of 18 m per minute.

If the surface of the roller 5 was allowed to ^{warm up to 90 °} C. by interrupting the supply of cold water, the film showed the tendency to stick to this roller.

Example 2

The procedure described in Example 1 was repeated with the modification that instead of the Ethylene polymer chlorinated ethylene polymer (molecular weight 18,000, ethylene polymer chlorinated to 27% chlorine content) was used and the pressure of the rollers was adjusted so that the Paper web a well-adhering film of chlorinated

tem ο, ι mm thick ethylene polymer in one Case and when a second attempt was made, it was 0.2 mm thick. The only difference compared to the procedure of Example 1 was that the temperature in the mouthpiece 160 was up to 165 ° C. The process runs just as smoothly as in Example 1 and the product obtained is also satisfactory.

B e i s ρ i e 1 3

The procedure described in Example 1 was repeated with the difference that a 0.01 mm thick aluminum foil was fed through the roller 4, which was placed on a 0.131 mm thick Kraft paper. Since the metal foil is too thin to be processed in the manner described in Example 1, the paper was simultaneously fed to the roller 4, namely in a form bonded to the aluminum foil, in order to protect the metal foil during the processing process. ^v It was worked under the same Temperaturibedingungen as in Example 1, and the Albzugsgeschwindigkeit was 18 m per minute, with a coating of ethylene polymer was produced a thickness of 0.04 mm on the metal foil. The paper could easily be peeled from the back of the film, leaving a flexible ethylene polymer covered with aluminum foil, which is useful as a waterproof packaging material.

Example 4

A polyamide, which was obtained by interpolymerizing a mixture of 40 parts of hexamethylenediamonium adipate, 30 parts of hexamethylenediamonium sebacate and 30 parts of caprolactam, was pressed into a film and applied to a 0.07 mm thick fabric using the apparatus described in Example 1 with Exception that both rollers were made of polished steel. The temperature of the mouthpiece of the extruder was kept between 240 and 250 ⁰ C, and the tem-

The temperature of the two rollers 4 and 5 was 100 ° C. The nozzle opening and the take-off speed were adjusted so that a 0.3 mm thick film of polyamide was obtained on the fabric, and the two rollers were so close together that a pressure on the film and the Tissue was exercised when they penetrated the gap between the two rollers, so that the covering adhered well to the base material. The polyamide film was in highly polished, smooth and continuous form and could be peeled from the fabric without difficulty.

The polished steel roller 5 used in this example was passed through a with a The steel roller with the engraved surface was replaced, and the apparatus was operated under appropriate conditions run with the result that a polyamide provided with a rough surface was obtained.

Example 5

The procedure described in Example 1 was repeated, except that the roller was provided with internal coils for the steam circulation 4, so that the temperature of the roll 104-110 ⁰ C was. The paper web was brought to about the same temperature as the roller during the time it was in contact with the polymer film. The resulting coated product is similar to that of Example i, but the bond between the ethylene polymer film and the paper sheet is even stronger.

An advantage of the invention is that it provides a fast process for Production of coverings from thermoplastic polymers on base materials is proposed, namely with polymers, which due to their sharply pronounced high melting point and their easy oxidizability at the calender temperatures in the usual calender process not let process- Another advantage of the invention is that this method only requires inexpensive, light-weight apparatus because it is used for union and connection The pressures required of both lanes are low because the polymer is in a molten state is present. In addition, effective temperature control can be achieved in a simple manner carry out. This method is particularly suitable for the production of thin coverings, in particular those from 0.25 mm thick up to 0.013 mm thick.

The material made according to the invention is, especially when it is among the preferred Conditions is established in which there is maximum adhesion between the base material and the polymer film enters, particularly useful for making wrapping and packaging materials, which represent a substitute for metal foils, regenerated cellulose, waxed paper or the like.

However, the invention can also be used for the production of coverings on fiber-free webs, such as cellulose hydrate and aluminum foil, under conditions in which there is no firm bond between the base material and the film. Such with pads provided webs can be else used further in that the polymer film is peeled off from the smooth surface of the base material, so that thin in this way, transparent strong films are obtained which may find useful in the packaging industry in the W ^T. Such polymer films have great strength, clarity, transparency, softness and uniformity of strength, and they are free from irregularities in the surface, such as holes, air bubbles, stripes, corrugations, cracks, which can easily occur when the coverings are made using solvents getting produced.

Multi-layer material can be according to

Invention produce in such a way that a paper web, which is initially on one side with the ethylene polymer covering was provided, is run through the apparatus again, this time with the polymer coating against the surface of the roller 4, whereupon the polymer coating on the previously free side of the paper web is applied. This creates a multi-layer material, consisting of the following layers: ethylene polymer - paper - ethylene polymer, that can be used for a wide variety of purposes, for example for packaging any objects. The second polymer coating can be the same as the first, but it can also consist of any other thermoplastic polymer.

Claims (10)

PATENT CLAIMS: 1. Process for covering material webs with linear polymeric plastics, characterized in that the molten film (3) of a usually solid linear polymeric plastic with a sharp melting point pressed into the material web (7) and the free surface of the molten film rapidly to a temperature below its solidification point is cooled. 2. The method according to claim 1, characterized in that that the material web (7) in the gap (6) of two adjacent in opposite Rotational directions of rotating rollers (4, 5) introduced and a molten film (3) of the linear polymer plastic perpendicular is fed to the bottom of the gap between the rollers (4, 5) without first one of the To touch rollers, whereby the melted film and the material web through under pressure the nip are guided and the roller in contact with the film at a temperature below the solidification point of the molten film. 3. The method according to claim 1 and 2, characterized in that the polymer consists of an ethylene polymer. 4. The method according to claim 1 to 3, characterized in that the temperature of the molten film (3) is between 220 and 260 ⁰ C when the material web is in contact. 5. The method according to claim 1 and 2, characterized characterized in that the polymer consists of a chlorinated ethylene polymer, the one Has chlorine content of 20 to 40 percent by weight. 6. The method according to claim 5, characterized in that that the temperature of the molten film in contact with the material web is between 135 and 160 ° C. ■ 7. The method of claim 1 to 6, characterized in that the molten film to a temperature between 45 and 65 ⁰ C is cooled. 8. The method according to claim 1 and 2, characterized in that the polymer is a Is polyamide. 9. The method according to claim 8, characterized in that the temperature of the molten The film does not exceed 275 ° C when it comes into contact with the material web. 10. The method according to claim 8, characterized in that the molten film to a temperature of
will. Cooled 20 to 100 ° C 1 sheet of drawings 3058 1.52