CN100396470C - Longitudinal orientation of a tubular thermoplastic film - Google Patents

Abstract

The improved method and apparatus for longitudinal orientation of a tubular thermoplastic film as it leaves an annular extrusion die aims at a better control of this orientation. On its travel between the exit orifice (21) and the draw-down means, the at least partly molten film passes an annular frictional device (101), and the frictional force set-up hereby is variable in controlled manner. This device is cooled from its interior (105) in controlled manner by means of a fluid cooling medium. The friction may be controlled by airlubrication with air pressed through holes (123) in the frictional device or through microporous metal, (102) or alternatively by sucking the film against the frictional device. In a preferred embodiment the extrusion out of the die is peripherical extrusion, and in another preferred embodiment the film contains a blend of at least two compatible or compatibilized polymers, and the main proportion of the orientation takes place while one is predominantly in a crystalline state and the other predominantly in a molten state.

Description

The portrait orientation of tubular thermoplastic film

The present invention relates to as the described method and apparatus of title.Particularly, the major part of this orientation is to finish by the annular friction parts between round exit that is arranged on the annular extrusion mould and calendering parts (roller, belt or like), wherein rolls parts (draw-down means) and is used for being under the molten state or in semi-molten state following time body being pulled out from mould at film.

The present invention has proposed a kind of special design to the manufacturing of cross laminates, wherein cross laminates comprises two or more films, these film uniaxial orientations or to take direction as the leading factor with a direction biaxially oriented, and these thin layers are laminated together along (dominating) direction interlaced with each other.In fact, this point can be achieved by following step: a tubular film is located generally along a single shaft direction, become this tubular film of spiral yarn shaped cutting then, thereby form a kind of rete with skewed popularity, then together, its orientation is intersected mutually with two or more such film lamination.Certainly, can also in laminated product, there be a rete generally along longitudinal register.

Replenish as a kind of alternative means or as a kind of, the deflection on the orientation can be achieved by when tubular film is pulled out this tubular film is carried out " reversing " in extrusion die under the state of basic fusing.

The inventor's WO-A-93/14928 has disclosed the technology relevant with the crosswise lamination film.

More particularly, method of the present invention relates to the method that a kind of thermoplastic material flow by at least a fusing that squeezes out is made the tubulose orientation film in an annular extrusion mould, in the method, this thermoplastic material flow that flows out from the ring exit of mould is subjected to cooling and at least longitudinally directed in state following time that it still is in local melting at least, so just can be by exporting and movably rolling under the pulling force effect that produces between the parts and realize portrait orientation.

In the method, to small part be under the molten state fluid when when outlet and calendering are mobile between the parts, will flow through an annular element and with this annular element (being referred to as friction means hereinafter) CONTACT WITH FRICTION, and in the contact process of fluid and these parts in this section, can regulate the temperature or tension force in this fluid, the frictional force that produces by contact can also controllably change.

This method and apparatus is open in DE-A-4308689.Portrait orientation is mainly carried out in this invention under molten state, and main transversal orientation in " crystallization range ", so just can improve the effect of blowing, thereby realizes transversal orientation.This invention and purpose of the present invention difference are: the objective of the invention is to promote portrait orientation.But in DE-A-4308689, the plug-in unit of an annular is arranged in bubble, although the setting of this plug-in unit is unconscious, but necessary, this plug-in unit impels film longitudinally directed by the friction to film.Also be provided with a nozzle ring around this ring plugin, this nozzle ring can be blown to body and plug-in unit.In this stage, this body is in " crystallization range ".Those functions of components just are first's film-" bubble " separated with other parts, like this, in the time of in thermoplastic enters " crystallization range ", just can blow out body forcefully by the overvoltage in " bubble ".Simultaneously, the pressure in the bubble remains near the ambient pressure in the zone that material is melted fully, so just can avoid transverse extension.

In DE-A-4308689, except carrying out the cooling of strong air from the bubble outside to it, also the bubble upstream side at above-mentioned plug-in unit carries out the inner air cooling.So will cool off, but this invention openly is not used for parts that the temperature of plug-in unit is controlled plug-in unit yet.Set point of temperature for plug-in unit, authorized pressure with the bubble downstream that is positioned at plug-in unit, may be controlled by the air capacity that blows to body from the friction of plug-in unit between out-of-date extrusion molding pipe at body, still, prior art does not relate to any content about friction is controlled.

One about the Van Leer that licensed to Holland in 1975 organize the patent of a subsidiary of this tissue maybe (inventor less than at submit applications time this application is further identified) relate to extrusion molding pipe under the solid state when it is pulled out in extrusion die on a plug that is positioned at body the content of portrait orientation.

But in fact, this method is difficult to realize that because can produce very strong convergent force when solid film is pulled out, and this convergent force firmly is fixed on body on the plug.

What should also be mentioned that at last, is: the plug that is positioned at extrusion molding pipe inside has been widely used in the calibration field of body.For example, referring to GB-A-2112703 and EP-A-0285368.

The invention provides a kind of manufacture method and device of tubulose orientation film, it is characterized in that: be arranged at bubble inside or outside friction means and cooled off, thereby make itself and contacted that surface of cooling medium stream reach the temperature that to control by a kind of fluid cooling media; Except temperature or the tension force in the fluid by adjusting fluid in fluid and friction means contact process, the frictional force that produces by CONTACT WITH FRICTION can also controllable mode change, the surface temperature of this friction means and friction are suitable for the component that temperature at fluid falls in the described crystallization range or produce longitudinal register during a little more than crystallization range between friction means and calendering parts, so just make the tubulose finished films have vertical shrinkage.This shrinkage preferably one be not less than 4 coefficient, referring to the contraction carried out in the upper limit of extrusion film fusion range experiment, this film has longitudinally shunk 1/4th or littler being heated to when shrinking detected temperatures its length.

Tubular film just can shrink in the longitudinal stretching process after leaving friction means, and perhaps the air pressure in the bubble may make body keep its (originally) diameter, even body is blown forcefully, thereby makes its transversal orientation.For this blowing process, need take special precautionary measures usually, specific as follows described.

By adopting the present invention, as mentioned above, just can be very accurately and/or more effectively adjust vertically fusing orientation.The present invention is extremely important under some application conditions, and is especially when the present invention is used to form above-mentioned cross laminates, more like this.

Directed for realizing high-caliber fusing, one embodiment of the present of invention are characterised in that: the orientation of finishing major part when polymeric material partial melting and partially crystallizable.In orientation process, at least 5% polymeric material crystallization is arranged preferably.Like this, just may contain a kind of mixture of forming by at least two kinds of polymer that can coexist or coexist in the polymer fluid, and under crystalline state, preponderate when a kind of polymer, and another kind of polymer just can be finished the orientation works of major part when preponderating under molten state.

Another embodiment of the present invention is characterised in that: the friction between friction means and the film can utilize in the hole that is pressed on the friction means or the air that is pressed in the micropore metal is controlled by air lubrication, and micropore metal formed at least one can with the contacted surf zone of fluid.

Perhaps, by fluid being drawn onto the control that realizes on the friction means friction.Like this, just can apply this swabbing action by micropore metal, perhaps make with the contacted surface of fluid to have a kind of flute profile decorative pattern, these grooves are the annulus around mold axis.Like this, these grooves just are subjected under the effect of controllable pressure.

Can adopt feedback element to acting on pulling force on the friction means and monitor and utilize, and feedback element is used for the excessive pressure or the not enough pressure of decision friction are adjusted, thus the directed angle of control.

If very thick and/or made by the very big polymer of a kind of molecular weight through the tubular film of extrusion molding, the surface temperature of friction means will fall in the fusion range of main film body or be higher than this fusion range so.But, this is a kind of situation of exception, under normal circumstances, when film is shaped and when that side towards friction means has a low-melting superficial layer through co-extruded, the temperature of these parts even be lower than the fusion range of this superficial layer, otherwise will be difficult to make film on friction means, to rub but level and smooth slip.This means: the time of contraction must be very short, solidify only to make extremely thin thin layer, and the main body of film remains on a temperature, and this temperature is near the draft temperature of regulation.The thin layer that has solidified will melt or local melting under the effect of film internal heat after it leaves friction means once more.

Directed for can controllably realizing the friction of specific height, the temperature of film in drawing process must remain in the crystallization range or be slightly higher than crystallization range, and this point is above being made clearly explanation in.In this case, with before friction means contacts, must carry out routinely effective cooling at film to film.For this reason, one embodiment of the present of invention are characterised in that: the provided upstream of friction means be equipped with one basic for ring-type, cylindrical shape or conical part (being referred to as to shake cooling-part hereinafter), these parts are used for the inside and outside of bubble cooled off.Fluid therefrom flows through in the mode that does not have friction or low friction substantially and is in contact with it, and this point for example can be realized by the air lubrication in micropore metal or hole.This part can be utilized a kind of fluid cooling media to be subjected to cooling effect internally and remain on an enough low temperature, thereby half is taken away to the major general can make that temperature in the fluid drops to heat that directed temperature required value need discharge.

In the upstream of friction means but the downstream of above-mentioned vibrations cooling-part (if adopting this parts) is provided with one has the part (being referred to as " trimming part of temperature " hereinafter) of similar structures with the vibrations cooling segment, the mean temperature that this part is suitable in the convection cell is finely tuned.

Following device feature preferably very near or connector by poor thermal conductivity interconnect:

A) constituted the mold component of side of outlet,

B) vibrations cooling-part (if any),

C) fine tune temperature parts (if any),

D) friction means.

The parts of all these devices all are positioned at the same side of bubble, or are positioned at the inside or the outside of bubble.

When tubular film leaves mould just, a kind of being used for the best approach that this film cools off uniformly and effectively is exactly that the angle that makes fluid be at least 20 degree with a relative mold axis flows out from outlet, its moving direction point to away from or towards the direction of this axis, then, contact with a cooling-part, this cooling-part is arranged near the outlet or with the mold component that constitutes a side that exports and links together.(certainly, the passage that constitutes outlet also relatively the axis of mould form one and be about 20 and spend or bigger angles).Above-mentioned cooling-part should be above-mentioned vibrations cooling-part (if employing), and perhaps, the fine tune temperature parts also are above-mentioned fine tune temperature parts (if employing), and perhaps friction means also is above-mentioned friction means.When section was checked vertically, most of zone that fluid is flowed through along above-mentioned parts all should be rounded, like this film will be when it flows through these parts or this assembly the edge rotate at least 20 gradually towards the direction of mold axis and spend.

When the outlet of mould is positioned on the outer peripheral face of mould, if perhaps mould is provided with one and limits the central cavity that forms by inner circumferential surface, and the outlet of mould is when being located on the inner peripheral surface of this mould, and the structure of this mould outlet can realize easily.When beginning to push, this structure is very suitable, holds melted material and is transported to whole cooling-part and being used in the temperature controlled annular element because this structure is easier.

For becoming 90 degree with a relative axis or leave for the fluid of mould near the angles of 90 degree, this point is highly beneficial.It also has other advantage: can regulate from different positions to the gap of outlet, and the general available flat-die of adjusting in this gap is carried out.For this reason, at least one side of outlet should be limited by an antelabium, and this antelabium will have enough pliabilities, can be on different positions in various degree adjusting be carried out in this gap.For this reason, can adopt mechanical part simple in structure, for example known plug-type screw rod or more accurate parts from the flat-die structure.

Will be appreciated that periphery extruding like this has been a technique known, for example see US-A-2769200 (Longstretch etc.), US-A-2952872 (Buteau etc.), US-A-3079636 (Aykanian) and US-A-3513504 (Ronden etc.).In these patents, the purpose of periphery extruding is: realize higher blow-up ratio (blow ratio) under the prerequisite that film is not caused damage.These patents do not disclose adopt annular element come thin film from laterally to axially movable direction, but these Patent publish be arranged at the adjusting parts in exit.

As mentioned above, tubular film can shrink along circumferential when it is pulled out in friction means in the longitudinal stretching process, its orientation just becomes real single shaft like this, perhaps also can under the effect of internal pressure, keep its diameter constant, even utilize higher overvoltage to its further blowing, thereby except the longitudinal component in orientation, also make it have a very big lateral orientation (component).For avoiding tubular film before leaving friction means, to be subjected to the effect of overvoltage, can take following measure:

If friction means is arranged on the inside of bubble, can leave the air (being called air 2 hereinafter) that is included in the fluid behind the friction means and separated before fluid touches friction means, being included in that part of air (being called air 1 hereinafter) and fluid in the fluid so, and air 2 remained on one under the pressure of ambient atmosphere, the pressure in the air 1 is maintained at about under the condition into ambient atmosphere pressure simultaneously.If friction means is arranged on the outside of bubble, for being centered around the bubble ambient air space of a sealing can be set between mould and friction means so, and the air pressure of bubble inside remained under the pressure condition of ambient pressure, the external pressure in the enclosure space then equates with the bubble pressure inside substantially.

An important use of the present invention just is to be used for making cross laminates, and this point was emphasized hereinbefore.In order to realize this application and other application, the fluid that leaves mould under normal circumstances should be two-layer, three layers or the more multi-layered composite laminate that is shaped through co-extruded, and for example tensile strength is main stor(e)y, the thin layer of medium level and/or is positioned at one or two lip-deep hot sealing layer.For making cross laminates, technological parameter should be suitable for providing a kind of directed in the following manner tubular film: vertically occupy an leading position, or become the hand of spiral along body.For realizing helix or " arachnoid " prevailing orientation, can comprise first end that rolls parts and comprise between second end of extrusion die and rotating that wherein extrusion die is provided with friction means, vibrations cooling-part (if adopting this parts) and " fine tune temperature parts " (if adopting this parts).

The present invention is described in further detail below with reference to accompanying drawings, and wherein all accompanying drawings are the cutaway view through the axis of annular extrusion mould.

Fig. 1 is the decline that is connected with the co-extrusion pressure mould of friction means, and in the process of pulling out, film is crooked on friction means.Extrusion operation is outwards to carry out at side face by the outlet that is positioned on the mould neighboring.

Fig. 2 is a view similar to Fig. 1, there is shown by being positioned at outlet on the mould inner peripheral surface to carry out situation to the inner peripheral surface extrusion operation, is provided with a broad tubular cavity in the center of this outlet.

Fig. 3 is a view similar to Fig. 1, also shows a vibrations cooling-part and fine tune temperature parts among the figure except friction means.

Fig. 4 is a view similar to Fig. 3, there is shown a kind of similar to Fig. 2 to the inner peripheral surface extrusion operation.

Fig. 5 shows the decline of co-extrusion pressure mould, in this mould, outlet is arranged on passes substantially on the position of plane die surface, and this die surface is perpendicular to axis, it is similar to the traditional ring mould that is used for film extrusion, but its outlet is with an angle directed inward that is about 20 degree.This mould is provided with vibrations cooling-part, fine tune temperature parts and a friction means.

Fig. 6 shows the modified structure of " friction means " shown in Figure 3 with original size.

Fig. 1 shows side face annular extrusion method from the outside, this extrusion can adopt the mould (one of a plurality of patent applications, the application just requires its priority) shown in Fig. 7 and 9 in the inventor's the application WO-A-02/51617 that does not conclude easily.The Reference numeral of mould itself is referring to these accompanying drawings.The axis of mould is parallel with chain-dotted line 1, but arrow is represented real axis and is positioned at the right side of accompanying drawing.Certainly, can also adopt the peripheral extrusion die of other structure.

This mould can be made of a plurality of bowl-types or disc-shaped part, these parts in Fig. 1 by 5,6,7a and 7b represent.Three kinds of component A, B and C form film B/A/C through co-extrusion pressure.If the present invention is used for thin film fabrication is become staggered lamination, the A that constitutes the intermediate layer so just becomes the layer that main intensity is provided, and has then formed superimposed layer and/or hot sealing layer (technology of relevant cross laminates in the above-mentioned patent of reference) as the B and the C of superficial layer.Like this, they just have lower fusion range, and generally its melt viscosity is less than the melt viscosity of A.As an example, A can be made of a kind of mixture that can coexist, and this mixture is made up of the bigger same polypropylene of 25% molecular weight, 25% HMWHDPE and 50% LLDPE; If the selected hot sealing layer of doing of C, it can be common LLDPE so; If the selected lamination of doing of B, it can be low-melting ethylene copolymer (for example EPDM) or low-melting metallocene polyethylene compound-or a kind of mixture or have the polymer of LLDPE so, and B converges at internal orifice 19 places and A, and C then converges at internal orifice 20 places and A.In the drawings, these two internal orifices are adjacent just, and for rheol reason, when surface component had lower melt viscosity than intermediate species, this set was highly beneficial.

These three kinds of components that merge radially flow to outlet 21 by exit passageway 18.After leaving outlet, tubular film B/A/C radially is subjected to the pulling force effect towards the outer surface of " friction means " 101.Here, film is bent upwards along the surface of " friction means " 101, and the surface of being somebody's turn to do " friction means " has constituted the part of annular compartment (" annular housing ").In moving process, it is lubricated that friction means 101 controllably cools off the line space gas of going forward side by side to it, thereby have a kind of controllable friction between friction means 101 and film.The temperature of this friction in the B/A/C film controlled the portrait orientation that carries out in film.The parts that are used for air lubrication, temperature control and friction control are as described below.

The B/A/C film makes its diameter become big by the overvoltage in the bubble leaving friction means 101 back, thereby makes it obviously along transversal orientation, if but the orientation with remarkable single shaft feature is best, blow-up ratio should be very low, even be reverse (contraction).Because convergent force is very big in the longitudinal stretching process, therefore under normal circumstances can when being shunk, body in bubble, form an overvoltage.

The B/A/C film that has left friction means 101 can be subjected to the further cooling of air (not shown) in known manner, preferably cools off simultaneously from outside and inside.Utilize known collapsing frame (collapsing frame) and driven voller in known manner (not shown) pull it, then, under normal circumstances, be wound into a plane film.Because the transmission with one group of reducing-pitch thread brings alternative collapsing frame to need very large pulling force, therefore, above-mentioned US-A-3513504 has also disclosed a kind of known method.

At outlet 21 places, die lip 25 is manufactured into adjustable version, so just can change its gap on every side, with the sudden change in the compensator fluid.When substituting the passage of tangible taper or tubulose, just can realize this point very simply with flat (as shown in the figure) or the passage that is almost flat.Adjusting work can be finished by a screw of lining up circular arrangement, and one of them screw 26 is shown in the drawings.In the drawings, it is painted as a simple screw, but it can also be a plug-type screw rod.Certainly, can also substitute these screws, as now the outlet on the flat-die similarly being regulated with thermal block.

As mentioned above, the periphery extruding is not a new technology, and is technique known to the adjusting that exports in this respect yet.But the present invention is even more important, because conventional means are very difficult for making the uniform film of thickness.These conventional means are carried out work according to following principle: the tubular film to extrusion molding on different peripheral positions cools off by different way, promptly by bubble being carried out the local air cooling, perhaps die lip is carried out local differential temperature cooling.But these systems effectively are not joined together with the cooling that contacts of film of the present invention.

To the parts that friction and temperature are controlled in the cooling and being used on friction means 101 of air lubrication, B/A/C film be described below.Friction means 101 can be made by steel, and the almost whole surface that film will pass through made by micropore metal, and this film is expressed as a circular slab 102 in the drawings.This circular slab can be tightened on the steel body portion of friction means 101.(all not shown screw that is used to connect different mold components in institute's drawings attached).Its aperture of this microwell plate can be about 0.01 millimeter.The pressure-air that is used for air lubrication is carried by a plurality of pipelines, only shows wherein pipeline 103 among the figure.This pipeline is distributed in the network of channels of friction means 101.Accompanying drawing only shows path 10 4, and this passage is that the center circularizes extension with the axis of mould.The passage that extends along perpendicular to the direction of path 10 4 is not shown in the accompanying drawing.In some cases, can also utilize swabbing action to substitute the overvoltage effect, when promptly very thick and/or molecular weight is very big when film, just can adopt swabbing action.

Friction means 101 is provided with a toroidal cavity 105, and cooling fluid for example water, oil or air can circulate in this cavity.Circulation of fluid can be with the surface temperature control of parts 101 in the scope in several years.For this reason, on the comparison position surperficial, be provided with a thermocouple (not shown) near this.

Cooling fluid is by a plurality of pipeline flow-direction toroidal cavities 105 and flow out in this cavity, only shows a pipeline 106 in the drawings.These pipelines and above-mentioned pipeline and following pipeline pass a big cavity that is positioned at mold center and extend, and this cavity is shown in the accompanying drawing 7 of patent application document WO-A-0251617.The pipeline of cooling fluid and a circulating pump and a heating/cooling unit link together.Similarly, above-mentioned pipeline 103 and gas receiver and compressor (or vavuum pump, if adopt swabbing action) link together, and also this compressor also is provided with the parts that can regulate pressure.

Friction means 101 is fixed on the mold component 6 by a plurality of arms (for example three or four), and one of them arm 107 has been illustrated in the accompanying drawings.Mold component 6 is provided with corresponding arm 108, and each arm all is fixed on the arm 107 by a thermal insulation board 109.The purpose of doing like this is to avoid to produce tangible heat transfer phenomenon between the mold component of heat and colder friction means.Each arm 107 all is provided with thin bridging part 110, this bridging part will enough approach, can record the variation of flexibility when changing, and in these thin parts at least one be provided with a suitable dynamometer, for example strain gauge parts 111 with the pulling force on film.Signal from these parts is sent to the parts of controlling overvoltage or vacuum, reducing or to increase the frictional force between film and the friction means 101, thereby makes its orientation remain required numerical value.In order not make 111 bending resistance excessive, each pipeline 103,106 and following 112 all comprises a undulatory part (not shown).

The required cooling of blow-up ratio that keeps having set can be provided by traditional parts with inner air and air pressure.These parts can pass the above-mentioned cavity that is arranged on the mold center place.This is a system that isolates with environment.A thin plate 113 that is installed between mold component 6 and the friction means 101 will keep under pressure bubble inside and the space between mould and friction means 114 to separate, and this space approximately remains ambient pressure by pipeline 112.If there is not dividing plate 113, film will leave outlet at it and fallen by the compression failure in the bubble in 21 o'clock so.

Put it briefly, because half heat that is used for need discharging when temperature with film is cooled to be about environment temperature will be pulled away by the contact cooling, and then adopt conventional cavity cooling system to cool off, therefore, being provided with " tower " of pulling out parts just can be very short.Make if desired its in the shape of a spiral the shape mode of extending carry out orientation, so these pull out parts just can be around the axis rotation of mould, and flat tubular film just can be wound up into the top of " tower ".

When adopting above-mentioned example, the main stor(e)y of this example is made of a kind of mixture, this mixture is made up of identical PP (solidifying when being about 160 ℃), HMWHDPE (solidifying when being about 125 ℃) and LLDPE (solidifying when being about 120 ℃) again, film will leave outlet 21 being about under 220-240 ℃ the temperature conditions, thereby realize gratifying portrait orientation, for example can under 130 to 150 ℃ temperature conditions, produce very big amount of contraction (drawdown).For can realizing enough cooling off fast, and for to avoid the low melting point superficial layer in the bubble to adhere on 101, for example the latter can be cooled to be about under 50 ℃ the temperature conditions.The length that film moves on 101 surfaces must be suitable, thereby when film leaves 101, make its mean temperature not be lower than 125 ℃.Directly the film that contacts with 101 approaches under the condition that partly will be cooled to below this temperature and solidifies, but when film left 101, this film again can refuse.

According to the vertical equilibrium relation between shrinkage ratio, temperature and the frictional resistance, most of contraction can betide before the PP crystallization or after the crystallization.Like this, for example leaving outlet 21 and thickness and be 2.5 millimeters film, to may contract to thickness before PP solidifies be 0.250 millimeter, and after this, continuing to be shrunk to thickness again is 0.05 millimeter.

In Fig. 2, show the view of extrusion molding that the periphery outlet of ring mould inner chamber is led in a disengaging, the axis of mould is represented by chain-dotted line 1.The top of this cavity separates by circular slab 115 and atmosphere.Above this plate, keeping overvoltage in the bubble, and carrying out the inside cooling.The parts that are used to exert pressure and cool off are not shown in figures.By thin plate 113, space 114 and atmosphere are separated, and the pressure in this space remain the pressure that approximates in the bubble (left side at film is illustrated) by pipeline 112.On the basis that Fig. 1 is described, be appreciated that the others of Fig. 2 fully.

From to the explanation of Fig. 1 as can be seen: be difficult to utilize the device relatively simple for structure shown in Fig. 1 and 2 to obtain the combination that needs most of orientation and shrinkage ratio.Shown in Fig. 3 to 5, structure complicated apparatus has more been improved these relations.In every kind of structure, all adopted three independently parts:

A) vibrations cooling-part 116;

B) fine tune temperature parts 117 Hes

C) friction means 118.

These three parts are keeping each other heat insulation by thermal insulation board 119.Each parts in three parts all are provided with and are used to guide lubricated parts with air,-or under the situation of friction means 118, its can be used for suction-, and be used to make the cooling fluid to circulate, this is similar with the explanation of those parts being done with reference to Fig. 1.These three parts can be subjected to respectively independently controlling.In the process through parts 116 and 117, the information of utilizing strain gauge parts 111 to send is controlled friction.Chain-dotted line 120 shows a plurality of grooves, and the pressure-air that is used for air lubrication can be overflowed by these grooves.

As the explanation that reference Fig. 1 and 2 is done, have a bit very important: when film leaves outlet 21, should avoid forming significant pressure reduction in the both sides of film.This point can be achieved by adopting dividing plate 121 and 122.

In the modification structures of friction means shown in Figure 6 118, friction is controlled by swabbing action, rather than control by micropore metal.Different therewith, these parts are provided with a plurality of grooves 124, and the spacing of these grooves is about 3 millimeters, the degree of depth is about 2 millimeters, and width is about 1 millimeter, but also is provided with a rounded top, in addition, also apply in control vacuum to it by hole 123.

By utilizing the above-mentioned example of making by suitable material, vibrations cooling-part 116 just can be remained on one easily and film can be cooled under about 140 to 150 ℃ temperature conditions, fine tune temperature parts 117 remain under the temperature that can regulate more accurately the temperature of film, for example 145 ℃, and parts 118 can remain on 50 ℃, adhere to avoiding.Take the very short time through only use on friction means 118, like this, the decline of film mean temperature is also just very little.

Claims (45)

1. one kind by making at least the fluid that is made of a kind of molten thermoplastic extrusion molding in the circular extrusion die make the method for tubulose orientation film, wherein said tubular film is made of at least a thermoplastic with crystallization range, in the method, the described fluid that has left the round exit of mould is cooled and is at least longitudinally directed, still be under the molten condition to small part simultaneously, described portrait orientation is by in outlet with movably roll and form a pulling force between the parts and carry out; And, in the method, at least local still be under the molten condition fluid when its outlet and roll between the parts when mobile will through the friction means of an annular and with this friction means CONTACT WITH FRICTION, it is characterized in that: described friction means can be arranged on by tubular fluid and limit bubble inside or the bubble outside that forms, and be subjected to cooling effect internally by a kind of fluid cooling media, thereby itself and the contacted surface of fluid are remained under the temperature conditions that can control, except temperature or the tension force in the fluid by adjusting fluid in fluid and friction means contact process, the frictional force that produces by CONTACT WITH FRICTION can also controllable mode change, the surface temperature of this friction means and friction are suitable for temperature at fluid and fall in the described crystallization range or produce the component of portrait orientation during a little more than crystallization range between friction means and calendering parts, thereby make the tubular film product have vertical shrinkage.

2. according to the method for claim 1, it is characterized in that: detect with reference to the contraction that the upper limit of the fusion range of extrusion film is carried out, described vertical shrinkage is one and is not less than and is about 4 coefficient.

3. according to the method for claim 2, it is characterized in that: the major part of described orientation is to carry out under polymeric material local melting and local-crystalized situation.

4. according to the method for claim 3, it is characterized in that: at least 5% polymeric material is by crystallization.

5. each described method that requires according to aforesaid right, it is characterized in that: described polymer fluid includes a kind of mixture, this mixture is made up of at least two kinds of polymer that can coexist or coexist, and directed major part is that a kind of therein polymer is occupied an leading position under crystalline state, and another kind of polymer carries out under the prevailing situation under molten condition.

6. the method that one of requires according to aforesaid right, it is characterized in that: described friction is to utilize by a plurality of holes on the friction means or carry out air lubrication by the air that micropore metal is pressed into to be controlled, and these holes or micropore metal have formed at least one and the contacted surf zone of described fluid.

7. according to the method for one of claim 1 to 5, it is characterized in that: described friction is controlled by described fluid is drawn onto on the friction means.

8. according to the method for claim 7, it is characterized in that: described friction applies by micropore metal.

9. according to the method for claim 7, it is characterized in that: the described and contacted surface of fluid is provided with a kind of decorative pattern of trough of belt, and these grooves are the circle around mold axis, and described groove is subjected to being in the low pressure effect under the control.

10. the method that one of requires according to aforesaid right is characterized in that: the feedback element by being used to regulate friction is to acting on pulling force on the described friction means and monitor and use, thereby the angle of orientation is controlled.

11. method according to one of aforesaid right requirement, it is characterized in that: the provided upstream of friction means is equipped with a cylindric or taper vibrations cooling-part that is roughly annular, and this vibrations cooling-part is arranged on bubble inside or outside, described fluid does not flow through from this vibrations cooling-part in the mode of having friction or low friction substantially, so just can cool off these parts from its inside and remains under the following state of temperature by fluid cooling media: half heat at least that need discharge when the temperature in the fluid dropped to directed required numerical value is taken away.

12. the method according to claim 11 is characterized in that: the fluid that flows through the vibrations cooling-part is subjected to air lubrication by micropore metal or by a plurality of holes.

13. method according to one of aforesaid right requirement, it is characterized in that: if the downstream of the upstream of friction means and the vibrations cooling-part that is limited by claim 11 that exists is provided with fine tune temperature parts, these parts are annular, taper or cylindrical shape, and described fluid flows through and internally it carried out cooling by fluid media (medium) from these parts in the mode of not having friction or low friction, thereby realizes the minor adjustments of mean temperature in the convection cell.

14. according to the method for one of aforesaid right requirement, it is characterized in that: the parts of following apparatus are arranged on the position very close to each other or by the lower connector of thermal conductivity and interconnect, all these parts all are positioned at the inside or the outside of bubble:

A) mold component, this mold component have constituted a side of outlet;

B) the vibrations cooling-part that limits by claim 11, if any;

C) the fine tune temperature parts that limit by claim 13, if any; And

D) friction means that limits by claim 1.

15. method according to one of aforesaid right requirement, it is characterized in that: the axis of the relative mould of described fluid leaves outlet with an angle that is at least 20 °, its moving direction away from or towards axis, the cooling-part with adjacent outlet setting contacts then, this cooling-part can be:

A) the vibrations cooling-part that limits as claim 11, if any; Or

B) the fine tune temperature parts that limit as claim 13, if any; Or

C) friction means that limits as claim 1,

When section was watched vertically, described fluid was rounded in the fundamental region of moving along described parts or assembly, like this film just can on these parts or this assembly through out-of-date along rotating at least 20 ° gradually towards the direction of mold axis.

16. the method according to claim 15 is characterized in that: the outlet of described mould can be positioned on the outer peripheral face of mould; Perhaps, limit the center cavity that forms if mould is provided with one by an inner peripheral surface, the outlet of mould can be arranged on the inner peripheral surface of this mould so.

17. the method according to claim 16 is characterized in that: the relative axis of described fluid leaves mould with one 90 ° angle or near 90 ° angle.

18. method according to one of aforesaid right requirement, it is characterized in that: if friction means is positioned at the inside of bubble, the part air that was included in before fluid touches friction means so in the fluid is that air 1 will be that air 2 is isolated with the air that is included in after fluid leaves friction means in the fluid, and air 2 remains under the pressure condition far above ambient atmosphere pressure, and the pressure in the air 1 then remains ambient atmosphere pressure substantially; If friction means is positioned at the outside of bubble, the space of a sealing so just is set, between mould and friction means to be used to making air surround bubble; And the air pressure in the bubble remains much larger than ambient pressure, and simultaneously the external pressure in the described enclosure space equals the bubble pressure inside substantially.

19. according to the method for one of aforesaid right requirement, it is characterized in that: described fluid is the co-extrusion pressure thing of at least two layers.

20. method according to one of aforesaid right requirement, it is characterized in that: for producing a kind of tubular film of main spirality orientation, if if comprising first end that rolls parts and comprising the vibrations cooling-part that extrusion die, friction means exist and rotate between second end that has the fine tune temperature parts.

21. the method according to aforesaid right one of requires is characterized in that: described technological parameter be suitable for providing a kind of vertically occupy an leading position or in body along the tubular film of hand of helix orientation.

22. the method according to claim 21 is characterized in that: described tubular film is cut into and can forms a rete with directed deflection dominant direction; And cross laminates is manufactured into and comprises two such retes, and these two retes are along its directed dominant direction cross arrangement.

23. make the purposes of tubular film according to one of claim 1 to 21, be used to make cross laminates, each lamination all comprises at least two films that are in turn laminated to together, and its leading orientation direction intersects mutually.

24. the purposes according to claim 23 is characterized in that: described tubular film is a kind of co-extrusion pressure thing with an external heat seal or lamination.

25. one kind is used for device that thermoplastic (A) is pushed, it comprises: a ring mould, this mould are provided with a round exit (21), and the material of fusion can flow out from this round exit; With movable calendering parts, be used for applying longitudinal pulling force to the tubular material that is squeezed by mould, make material at the state lower edge portrait orientation of local melting at least still thus, between outlet (21) and calendering parts, be provided with annular friction parts (101), the setting of this friction means is used for contacting in body inside or outside with the fluid of thermoplastic, it is characterized in that: described friction means (101) comprise can convection cell and friction means between the parts controlled of friction, and described friction means is cooled off by the fluid cooling media that is flow through by the cavity (105) that is positioned at friction means (101) inside internally, thereby change the tension force between calendering parts and the friction means, portrait orientation is had controllable use.

26. device according to claim 25, it is characterized in that: described material fluid flows through from the surface of described friction means, the surface of this friction means is provided with a plurality of holes (123) or is made by micropore metal (102), so that air can flow inwards and outwards.

27. the device according to claim 26 comprises: a vavuum pump, this vavuum pump are used to make inside circulation of air to cross described hole (123) or micropore metal (102) flows in the friction means.

28. the device according to claim 27 is characterized in that: the surface of described friction means is provided with the decorative pattern of trough of belt, and these grooves (124) are circular around the axis of mould.

29. the device according to one of claim 25 to 28 comprises: one is used to measure the parts (111) that act on the tension force on the friction means and utilize the friction between this measurement result control fluid and the friction means.

30. device according to one of claim 25 to 29, it is characterized in that: a vibrations cooling-part (116) that is roughly annular, cylindrical shape or taper is arranged on the upstream side of friction means, fluid through extruding flows through and is cooled off by the fluid cooling media that flows through from its inner cavity (105) from this vibrations cooling-part in the mode of not having friction or low friction, can make fluid be cooled to half heat at least that is suitable for required release under the directed temperature conditions thereby take away from fluid.

31. the device according to claim 30 is characterized in that: described vibrations cooling-part (116) is provided with the air lubrication parts that can be lubricated the passage of the fluid that flows through described surface.

32. the device according to claim 31 is characterized in that: described air lubrication parts comprise the hole in a plurality of surfaces that are arranged on the vibrations cooling-part or be arranged on the vibrations lip-deep micropore metal (102) of cooling-part and one be used to make air to pass through these holes or the outwards mobile compressor of micropore.

33. device according to one of claim 25 to 32, it is characterized in that: one is roughly the fine tune temperature parts (117) of annular, cylindrical shape or taper if be arranged on the downstream of upstream side with the vibrations cooling-part that exists of friction means, and extrusion fluid is not there to be friction or the low mode that rubs flow through and flow through its inner cavity (105) from the vibrations cooling-part flow of fluid medium institute cooling.

34. the device according to one of claim 25 to 33 is characterized in that: be provided with the connector of conductivity of heat difference between the following parts, and following parts all are arranged on the inside of bubble or all are arranged on the outside of bubble:

A) mold component (6), this mold component have constituted a side of outlet;

B) vibrations cooling-part (116), if any;

C) fine tune temperature parts (117), if any; And

D) friction means (101).

35. device according to one of claim 25 to 34, it is characterized in that: described mould is configured to be enough in and will be at least the version that 20 ° angle is left outlet with one through the relative mold axis of material fluid (1) of extruding, and this angle is pointed to or away from described axis; And, when section is watched vertically, be arranged on the parts in outlet downstream, promptly shake cooling-part (116), fine tune temperature parts (117) or friction means (101) and have a rounded profile, material stream is flowed around described rounding profile, thereby make its direction deflection at least 20 degree.

36. the device according to claim 35 is characterized in that: described outlet (21) is positioned on the outer peripheral face of mould.

37. the device according to claim 36 is characterized in that: described friction means (101) is arranged on the inside of bubble.

38. the device according to claim 35 is characterized in that: described outlet (21) is positioned on the inner peripheral surface of mould.

39. the device according to claim 38 is characterized in that: described friction means (101) is positioned at the outside of bubble.

40. the device according to one of claim 36 to 39 is characterized in that: the relative axis of described squeeze wood materials flow leaves mould with the angle that is about 90 degree.

41. device according to claim 37, comprise: be used for the parts (113,121) that body inner space (114) that will be positioned at friction means (101,118) the place ahead and the body inner space that is positioned at the friction means rear separate, but also comprise and being used for being positioned at the parts (112) that friction means (101, the 118) space at rear applies a bigger air pressure.

42. device according to claim 39, comprise: the parts (113,122) and being used to that are used for the space (114) of sealing between mould and friction means (101,118) apply the parts of an air pressure that is higher than the environmental pressure in the enclosure space (114) and are used for the space in the bubble and atmosphere being separated and applying parts (115) that are higher than the air pressure of environmental pressure in the bubble.

43. the device according to one of claim 25 to 42 is characterized in that: described mould carries out co-extruded at least two kinds of thermoplastics (A, B, C).

44. the device according to one of claim 25 to 43 is characterized in that: described calendering parts can rotate relative to extrusion die (5,6,7a, 7b) and friction means (101,118).

45. the device according to one of claim 25 to 43 also comprises: be used for to be positioned at the parts that the body that rolls the parts rear cuts into the rete with directed deflection dominant direction; Be used for two such retes so that the cross one another mode of its leading orientation direction parts laminated together.

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