DE1704027A1 - Process for the manufacture of a strip of plastic material and the product obtained thereby - Google Patents

Description

1BERLIN33 8MUNICH27

AKTSi ¹ SSf " ^Dr - ^Ιη δ · HANS RUSCHKE

n: «ν-» »Dipl.-lng. HEINZ AGULAR

PATENT LAWYERS Bank account: Munich 66277 Bank for trade ti. Industry bank account: Deposit kasse 32 'Dresdner Bank Berlin 33 Munich Teplifeer Strasse 42 Dep.-Kasae Leopoldstrasse

Account 32 7808 J7 _{n / n} Account 59515

'/ U 4 U

Account 32 7808 J7 _{n / n}

Telegram address: '/ U 4 U Z / Telegram address:

Quadrature Berlin "Quadrature Munich

E 391

Societe Anonyme dite: Ethylene-Plastique, Paris, France

Process for the production of a strip from plastic material and the product obtained thereby

For some time now attempts have been made to use the metallic straps used to tie packages and boxes, to be replaced by tapes made of thermoplastic material. These bands show as a result of a suitable pulling or Stretching considerable mechanical resistance in the longitudinal direction. But in general they are with everyone in the transverse direction, bends or splits were very fragile. Incidentally, this transverse fragility is complete Understandable, since it is known that stretching the ribbons in the longitudinal direction provides an orientation for all macromolecules in a preferred direction, which results in considerable anisotropy of the material.

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The invention relates to a method for making strips of plastic material which have a very good resistance to tension in the longitudinal direction and a good ability to bend in the transverse direction. This method is characterized in that the plastic material is subjected to a temperature of 25 to 100 ^° C. below its crystalline melting temperature with a mechanical treatment which has the purpose of locally thinning the strip of plastic material according to a certain number of flutes or grooves which are arranged in the longitudinal direction, whereupon the strip of material thus obtained is stretched in the longitudinal direction in order to give it in a certain way the optimum mechanical resistance in the direction of pull.

The method according to the invention is so through the execution of grooves by a suitable mechanical Work, characterized by the temperature of the material at the moment when this mechanical work is carried out, by the longitudinal stretching of the product obtained and finally by the fact that this tape made of plastic material.

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Various elements of the invention are for example depicted in the Pig, 1-14, in which show:

Pig. 1 with a band element in enlarged cross section Hute, noticing the spontaneously formed contraction on the surface of the ligament, which is not is mechanically attacked, at least in the case where the original tape is only on one of its Surface is attacked,

Fig. 2 shows the attack ane in an enlarged cross section Tape on one of its faces with a wheel, the angle of attack is 30 °,

Fig. 3 shows a part of the attack on a tape on one of its surfaces, a series of wheels (Fig.3a) and in section the result obtained on the tape itself (Fig. 3b). After the final stretch will the width of this band be greatly reduced;

4 shows in section a device which shows a possible arrangement of the wheels around a cylinder, over which the plastic material band loops,

Fig. 5 is a section of an execution to grooves through to form mechanical attack of a tape by means of metal cables,

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Mg. 6 a section along line VI-VI in Pig. 5,

Pig. 7 shows a section of a device, the plan view of which is that of Pig. 5 is analogous, but using a ribbed roller,

8 and 8a, 9 and 9a complete system diagrams for the production of tapes according to the invention,

Fig.10 is a cross-section of a strip of layered Material used to make a tape,

11 shows a cross-section of a band made of joined together Strips (Jones) are formed, which can be used for the production of a tape,

Fig.12 is a cross section of another for manufacture a tape usable strip,

Fig. 13 is a cross-section of the tape obtained by mechanical attack of the tape shown in Fig. 10,

FIG. 14 shows a cross section of a band which is produced by the mechanical attack of the one shown in FIG Band is obtained.

The grooves or flutes of the belt are made by mechanical action of a simple or combined

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put tape of plastic material obtained, wherein this attack takes place when the plastic material, in whole or in part, is in the solid state.

If the mechanical attack takes place on one of the surfaces of the tape, one obtains e.g. a tape, of which an element in cross section in Pig. 1 is shown. The opening angle A is on one side Note the groove, which in this example is 45 °, which automatically crawls along the edges of the groove of the material obtained roundings Ar and the contraction § spontaneously formed on the surface of the strip, which is opposite to the attack surface by the wheel, this contraction allows in Relationship with the groove a special one as a resistance hinge to obtain a suitable profile.

However, according to the invention, the grooves of the belt can also be opened by simultaneous mechanical attack make the two faces of the tape. Most of the time, the two surfaces of the ligament become the generators at the same time attacked following, which correspond in pairs on both sides of the tape "

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The grooves can be formed, for example, by means of small wheels. One such attack is in Pig. 2 shown, wherein the wheel then has a smaller angle of attack than 120 °, preferably between 30 and and a fillet at the tip of the radius between P / 4 and P, where P is the depth of the groove.

The depth of attack is such that the thickness at the bottom of the groove is between 15 and 50 # of the original Thickness, the ratio being smaller than the original thickness being greater. The remaining thickness will be no higher than 0.8mm and no less than 0.2mm. After the longitudinal stretching, this thickness is converted into the An interval of 0.05 to 0.3 mm must be observed.

The number of grooves is chosen according to the width of the belt. Each groove is, for example, by a or several consecutive cogs hollowed out.

If you have multiple grooves viii you can either use fixed wheels, in which case the pushed back material of the grooves thickens the intermediate banks, whereby this changes the state of orientation in these zones somewhat, without incidentally any noticeable Loss of strength for the eventually stretched tape

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after itself or through the use of follower wheels that slide laterally on their axis, whereby each naturally adjusts in the groove hollowed out by the previous wheel. In this case they are Attack wheels Distance and fixed wheels. Fig. 3a explains this method of execution. You pushing back the Material through the cogs successively widens the band. Fig. 3b shows such a band before and then after the formation of the grooves.

The wheels can be in one plane or, in contrast, can be arranged around a cylinder, on which the plastic material band rests. These the latter arrangement is shown in FIG.

It is possible according to the invention to produce several strips starting from a single strip of suitable width to build. The grooves hollowed out by the wheels form pre-cut lines and the transverse orientation in the Residual thickness favors a free cut. This cut takes place before stretching. It either happens using a small burr or a circular knife.

The mechanical attack of the plastic material band can also be done with the help of suitably tensioned metal

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cables are carried out, which can be vigorously act on the plastic material strip that has a Rolls with a smooth surface. It can also be done with the help of a steel belt with a smooth surface be carried out, which is pressed with force on one of the sides of the plastic material strip, which passes over a motorized roller with a suitably ribbed surface

These methods of attack are shown in FIGS. 5-6 and schematically.

Fig. 5 shows one of the embodiments of the invention. One or more cables are around two motor rollers 1 and 2 arranged around, the distance of which is adjustable. Another roller 3 ensures a suitable tension and is also adjustable. The band 4 made of plastic material goes over a roller 5 »whose surface is smooth. By regulation the relative position of the rollers 1, 2, 5 and the tension of the cables due to the roller 3 push the cables into the plastic material band, during the rolling of the same and hollow out the intended grooves there.

FIG. 6 shows the section VI-VI of the device shown in FIG. The roller 5 can be found there

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again, on which the band 4 made of plastic material is applied and you can also see three cables 6, which are located on the upper surface of the band 4.

Bas pressing the metal cable into the plastic material band happens during the passage of this belt between rollers 1 and 5 on the one hand and 2 and 5 on the other hand. The roller 3, the position of which can be regulated, has the main purpose of "every reciprocal sliding of the Cable and tape to prevent it.

It is also possible according to the invention to use a somewhat different device, one end view of which is analogous to that shown in FIG. In this case one uses the two reels and 2 wound, a steel band 6 with a smooth surface. This band can be adjusted by regulating the position of an auxiliary roller 3 can be tensioned appropriately. The so tensioned band places the band 4 made of plastic material firmly against a Roller 5, the surface of which shows uninterrupted ribs, which are arranged perpendicular to the axis of rotation of the roller 5 are. A sectional view YI-VI of this device is shown in FIG. There you can see the steel belt 6, which is supported on the roller 5, the one with the ribs

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is provided, wherein the plastic material band is denoted by 4.

There the impression of the ribs of the roller in the plastic band occurs during the passage of this Belt between the rollers 1 and 5 on the one hand and 2 and on the other hand.

The invention is of course not limited to the production of the grooves using a single device, as shown in Figs. 5-6 or 5-7, limited, but also includes the possibility in Use several devices of the same type in the series. In the case where several devices are used in series, and since it is known that each of them under different conditions (for example! temperature of the belt) can work, industrial tests will indicate which device type (type 5-6 or 5-7) is the most indicated is. It will be understood that the various devices mounted in series are of the same May be of different types and that the plastic material tape between each of them is the appropriate one can experience thermal and / or mechanical treatments.

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· ■ ι Ι ™

The shape of the metal cable or the ribs with which the cylinder 5 is provided can be triangular, be cylindrical or other. The angle of attack can be greater, smaller or equal to 120 °. Figs. 6 and show attack elements, the shape of which is semicircular in section is, but this shape can also be elliptical or quasi-elliptical. Incidentally, if you have several devices Used 5-6 or 5-7 in series, as previously mentioned, these different devices can be used provided with attack elements of various fora These elements of course depend on the degree of indentation to be carried out and the working conditions used are adapted.

FIGS. 8-8a and 9-9a show complete system diagrams for the production of strips according to FIG Invention,

Fig. 8 shows a plant for the extrusion, grinding and stretching of thermoplastics Tapes according to the method according to the invention. The squeezed, cooled by immersion and dried

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Tape is placed on a series of cylinders located in a heating cabinet 1 which is placed on top of the selected temperature of the master cylinder 2 is brought, on which the wheel treatment takes place, is picked up again by the driving cylinder, passed into the furnace 3, where the stretching takes place and on the Series of pulling cylinders 4 brought, their peripheral speed η times the peripheral speed of the previous one Rolling, where η is the draw ratio.

Fig. 8a shows a plant very similar to the previous one, but which differs in that the pressed tape is cooled by touching a calender made of thermostat cylinders, then over the Thermostat heating cylinder 2 goes, in the contact of which it is heated up again to the desired temperature and grooved by a ribbed cylinder 3 of large diameter.

The preheating rollers are either movable or supported, with the exception of the entry roller, which is driving is. They are also either provided with a hood or arranged in a heating cabinet. The main roller on which the grooving takes place is driving, as are all other cylinders downstream.

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In particular, the detection upstream of the furnace must be sufficient so that there is no excessive voltage at the level of the grooving cylinder and that there are no premature longitudinal stretching results, which would make regular grooving impossible.

9 and 9a show a plant according to a modification of the method. In this case, the pressed strip is taken up with or without stratification on a calender, preferably in a bath which allows better cooling control and then it goes directly to the grooving cylinder 2% the two versions of those shown in FIGS. 8, 8a Grooving devices can be found here again. Finally, it is taken up by a classic stretching system. During its passage through the cylinder row upstream, the belt cools down considerably and crystallization takes place. It is reheated in the oven to the preferred temperature for drawing.

Such are the various mechanical designs that may be used to manufacture it of tapes according to the invention can be used.

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The fillets or grooves designed in this way preferably have a thickness or strength in their least thick part which is between 0.15 and 0.5 times the thickness of the initial band, which is practically always of a thickness is less than 5 mm. The width of the grooves can be variable. There is often interest in the fact that these grooves are relatively wide and show a kind of flattening at their bottom. That before stretching under these The hinge band is relatively wide in terms of its thickness and if one considers the » Thickness part of this hinge band (charnlÄre) as constant you have to look at the relation

Width of the hinge \

Thickness of the hinge

to have.

The temperature at which the mechanical work must be carried out has a certain significance. she must preferably be from 25 ° - 100 ° Celsius below the crystalline melting temperature of the material used lie. If the temperature used is too low, it is found that the forces to be achieved at the time of mechanical work are very large what

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results in the use of heavy and expensive apparatus. If, on the contrary, the tape at is processed to an elevated temperature, one obtains an orientation effect of the mechanical work Material that is far too weak and the band is relatively at the point of 4 grooves or grooves remain fragile when the tape is subjected to successive bends. But the must also The tape subjected to mechanical work does not necessarily have to be distributed in its thickness in all the points have the same temperature. For example, a sensible choice of a surface temperature of the Of the band, which is relatively low, and a depth of temperature which is sufficiently high, one orientations of certain material layers alone and / or of special effects on the bands formed from different ones Materials can be obtained as shown below.

After the grooves are formed, the strip of material is kept at the same temperature or is slightly reheated subjected to a longitudinal drawing or stretching in such a way that

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to give it the necessary mechanical properties for its later use. Ee is Surprisingly, it has been found that the transverse orientation of the material at the level of the grooves, locally caused by mechanical work is, and which gives the band obtained its flexibility in the transverse direction, almost entirely in the course of longitudinal drawing in such a way that the flexibility of the material is maintained after stretching.

The method according to the invention is suitable for all crystalline plastic materials in the form can be pressed or shaped from strips or ribbons. This is particularly the case with polyethylene, with polypropylene, with polyamides ... The polypropylene is the preferred material for the Implementation of the invention. In this particular case, the grooves are made at a temperature of 70 to 140 ° C carried out, preferably at a temperature between 95 and 130 ° C, and the stretching is carried out at a temperature below 140 C with a stretching ratio which is between 6/1 and 10/1.

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1 0 9 8 1 9/1 R 0 6

i / 04027

But the tape made of plastic material can also be starting made of composite tapes, those as shown, for example, in FIGS. 10-14.

A layered material is then used, which consists of different plastic materials, each in the form of superimposed layers cover the entire width of the starting tape, either in the form of joined strips (Jones) of different Forms, the entirety of which forms the final link, that of mechanical work and stretching is subjected.

This layered material is formed from at least two plastic materials that are suitable For example, when it is warm at the moment of squeezing out strongly among each other or after this Using known methods to connect. It is well understood that the connection between These plastic materials are sufficiently strong that the resulting composite material of the later mechanical work can be subjected to both without separating and thereafter a particularly strong band

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Forms in the longitudinal direction than in the transverse direction. A material is preferably used which consists on the one hand of an isotactic polypropylene and on the other hand of another polyolefin or a crystalline copolymer of α-olefins. The preferred formation elements are isotactic polypropylene and a copolymer which contains at least 80 $ of radicals of the type ι

CH-

-CH ₂ - CH-

contains.

The following, non-limiting examples illustrate the invention.

example 1

It is of a homopolymeric polypropylene isotaktisohen crystalline heat liquid index of = 1.5, measured according to NF "T. 51016", but at 23O ⁰ C and under 5 kg load and isotacticity $ 95. A tape width 1 = »30 mm, thickness e = 2 mm, weight per meter = 54 g, is first grooved at a temperature of 110 ° C. Three equidistant grooves are formed so that

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the remaining thickness is 0.45 mm. It is then stretched in the ratio of 8/1 and at the temperature of 12O ⁰ C, that is, the weights per meter before and after the ratio of 8/1 have. The grooving speed is 8 m / mn.

A tape with a thickness of 0.7 mm in the full parts and 0.15 mm at the bottom of the hinge tape, with a width = 13 mm and weight per meter = 6.8 g is obtained. The breaking resistance is 298 kg, namely 43 _f 8 kg / g / m (mean of 10 measurements) - (the unit kg / g / m expresses the resistance on a fictitious tape Ig in meters j it is based on the "metric resistance" which expresses the tape length, the weight of which is equal to the breaking resistance by the relation 1 kg / g / m = 1000 m.)

After 100 alternating bends according to the central groove, the tape is still intact.

Example 2

If you proceed under the same conditions as in the previous example, but without grooving one a tape 11.5 m wide, {*] <- more self Thickness e = 0.65 mm, weight 6.8 g / m. H.mi has a breaking resistance R = 302 kg found (mean of 10 Hc? Ο solutions)

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1 0 9 B 1 9/1 ^ 0 ί
BATH ORIGINAL

namely R kg / g / m = 44.4 kg.

The tape "breaks on the first bending attempt ..

Example 5

A homopolymeric polypropylene with a higher molecular mass than that previously used is used (Melt index: 0.5 f isotacticity = 96 #). One goes from a band of: 1 = 50 mm and e = 3 mm, weight 135 g / m. Three equidistant grooves are formed, residual thickness on the bottom of the grooves = 0.6 mm, by grooving at 100 °. After stretching at 120 ° in the real ratio of 7.1 / 1, one obtains a tape 22 mm wide, 1.1 mm thick at most, thickness at the bottom of the grooves 0.22 mm, weight 19 g / mj the running speed when grooving is 5 m / mn. The resistance is 770 kg, namely 40.5 kg / g / m. The ribbon tolerates more than 50 alternating bends without splitting.

Example 4

The procedure is as in Example 3, but a propylene copolymer is used which contains 4% ethylene. A tape is obtained with a resistance of 700 kg, namely 36.8 kg / g / m, After 100 alternating bends, the tape is still intact.

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Example 5

By pressing out of two extrusion presses which deliver into the same nozzle, a strip of layered material is obtained, consisting of a layer of polypropylene with a thickness of 3e and a layer of a propylene-ethylene copolymer with a thickness of _e. After cooling the material passage TdIs to a temperature of the order of magnitude of 90 ⁰ C, the tape is mechanically attacked by means of a wheel or a wire or the ribs located on a cylinder on the tape surface made of polypropylene in order to access a groove with a depth in the vicinity of 3e form. Examination of a section of the tape thus obtained shows that most of the polypropylene subjected to this mechanical action has suffered creep and that at the point of this mechanical action it has formed a very thin layer of polypropylene, which is closely connected to the layer below Copolymer is connected. The grooves formed in this way are particularly strong after stretching and do not tear despite numerous bends.

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Example 6

By the same procedure as in Example 5, a layered material was made consisting made of a middle layer made of polypropylene and two adjacent layers made of propylene and ethylene copolymer. Such a band is shown in cross section in FIG. You can see the middle layer (1) made of polypropylene there and the adjacent layers (2) made of copolymer.

The tape obtained is superficially cooled in such a way that the copolymer solidifies and that the inner polypropylene maintains a temperature sufficient to achieve an easily deformable plastic state retain »This material is then subjected to mechanical work in order to pass the grooves between to produce one or more pairs of rollers, at least one of which is provided with protruding ribs is. The band obtained is then stretched. Examination in section shows that the two superficial layers made of copolymer have approached, sometimes until they touch, in the places where the mechanical Work is done. The grooves created in this way are particularly resistant, be it to the effects

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of tension, be it against the bending and tearing tests.

The band obtained is in cross section in Pig. 13 shown. You can see the polypropylene layer (1) there, the thickness of which has been considerably reduced at the points that are the mechanical points of attack of the material correspond. The co-polymer layers are shown in (2).

Example 7

Through a nozzle fed by two extrusion presses, one with polypropylene and the other with propylene and ethylene copolymer is obtained, a tape composed of strips (joncs) is carried out, which alternately is composed of one and the other of these materials. One such band is in cross section shown in FIG. You can see at 1 the strips made of polypropylene and at 2 the strips made of copolymer. After cooling to a temperature of the order of magnitude from 60 ° C is carried out mechanically in the strips of copolymer grooves. Then the whole thing becomes a longitudinal stretch subject. This gives a tape with excellent properties, which in cross section is in 14 is shown. The mechanical attack took place here

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took place on both surfaces of the tape at the points where the copolymer adheres to the surface of the same occurs.

You can also use, for example, tapes that consist of a core made of polypropylene, on the through simultaneous pressing on one or both sides of the tape made of other thermoplastic materials are = such a band is shown in fig. 12 shown. The mechanical educational work is then at one or both surfaces of this tape carried out at the points of these tapes, proceeding as in Example 6, " i.e. with a distribution of temperatures such that the polypropylene located inside the belt is the plastic Maintains state.

The tape or composite strip used to make the tape can be made by pressing a copolymer film against a tape of polypropylene in the molten state on one or both sides. The Kopolymerfilm is preheated, then pressed onto the polypropylene by means of rollers, one of which can be heated up to a temperature of 12O ⁰ C at least. When that layered

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Material is received, it can be processed immediately, as indicated in Example 6, to produce the finished tape in a camouflaged manner.

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Claims (7)

T7Ü4027 claims 1.JVerfahren for producing a strip of plastic material, characterized in that a strip of plastic material of which at least a part of a temperature of 25 - 100 has ⁰ C below the crystalline melting temperature of the plastic material used, is subjected to a mechanical treatment, the purpose of the has to form grooves or grooves and that the band obtained is later stretched in the longitudinal direction. 2. A method for producing a tape according to claim 1, characterized in that the mechanical treatment by means of a wheel or a game of wheels or a metal wire or one provided with ribs Roller is running, 3. A method for producing a tape according to claim 1 and 2, characterized in that the plastic material used is polypropylene, the isotactic ratio of which is higher than $ 90, in which the grooves are at a temperature of 70-14O ⁰ C and preferably 95 - 130 ⁰ C and that after the formation of these grooves it is drawn at a temperature of approximately HO ⁰ C with a draw ratio which is between 6/1 and 10/1, -27-109819/1506 4. A method for producing a tape according to claim 1 and 2, characterized in that a composite strip is used as the plastic material strip, which consists of at least two plastic materials which are interconnected and arranged in superimposed layers, each covering the entire width of the starting strip or which are arranged in longitudinal strips connected to one another, one of these plastic materials preferably being a polypropylene, the isotactic ratio of which is at least 80 fo , the other preferably being a crystalline copolymer of propylene. 5. A method for producing a tape according to claim 1 and 2, characterized in that the plastic material tape at least one superficial layer uninterrupted or interrupted across the width of the strip contains crystalline copolymer of propylene and an underlying core made of polypropylene, and that the mechanical work to form the grooves on the surfaces of the belt causes this copolymer in the same way Level lies, under such temperature conditions, that the underlying polypropylene has plastic properties maintains. -28- 109819/1506
BATH ORIGINAL 17Ü4027 6. According to any one of the preceding claims 1-5 obtained tape, characterized in that the thickness of the material at the bottom of the groove before stretching between $ 15 and $ 50 the initial thickness of the plastic material band, this initial thickness being less than 5 m ». 7. According to one »of the preceding claims obtained tape, characterized in that the hinges (or grooves), the »echanically by attack of the Auegangsbandes on the one or both surfaces are formed, in front of the streoken in their »thinnest part a thickness and a width have in such a way that one has the relationship Width of the so-hinge Thickness of the hinge 8 · According to one of the claims 1-5, which has a large mechanical Has assumed resistance, characterized in that it contains one or more grooves running parallel in the Are arranged longitudinally and whose depth corresponds to 50 - 85 $ 4 output dioke of the plastic band, which served to prepare this volume. O / Wr 109819/1506