DE2652342A1 - PROCESS AND DEVICE FOR MANUFACTURING OBJECTS WITH MULTI-LAYERED WALLS AND THE OBJECTS RECEIVED - Google Patents

Description

DR.-ING. GERALD KLOPSCH 50OO COLOGNE 1 PATENT ADVERTISER MARSPLATZ 11

November 15, 1976 Kl / En

Raychem ApS,

Formervangen 16, DK-2600 Glostrup (Denmark)

Verfahren_und Vorrichtung_zur_Herstellung of Gegenständen_mit _e mehrschichtigen_Wänden_sowie

The invention relates to a method and a device for producing an article with a multilayer Wall as well as this object. The invention particularly relates to articles made by extrusion of a melt, e.g. a thermoplastic material.

In the production of hollow thermoplastic objects, it is relatively easy in some processes, for example compression molding, to produce an object with different wall thicknesses in different areas by having different distances between the core and the mold in different zones. In the formation of a multi-layer tubular article by continuous extrusion, the use of concentric dies has been proposed, where-. with two or more materials 2u pipes of constant ^:

Total wall thickness are coextruded and the wall thickness of each individual component is also constant, i

In the case of an extrusion process from a ring nozzle, e.g. at j the blow molding, may ee necessary »a,« weeks vari- ■■! tion of the wall thickness over dl * length of the object the '

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Cross-section of the annular gap of the extruded material to vary over time. In theory, this can be done with any Method of varying the dimensions of the dome or shape at the point where the Melt is extruded, but this is usually done by tapering or expanding the mandrel and / or shape as well as a relative axial movement between mandrel and mold for the purpose of changing

^; tion of the thickness of the resulting annular gap achieved. There are already a number of methods for automatic

■ lo control of the change in wall thickness / molding - / suggested been, including the method of US-PS 3,712,772, whose Disclosure is hereby made the subject of the present application by reference.

When a hollow body, e.g. a container, in the form of a cup or a pot is to be provided with an inner lining or an outer coating made of another material, It is usually necessary to first make the item yourself and then the lining or outer coating to be applied to its surface, e.g. by dipping, brushing or boiling. Limit such procedural requirements naturally the type of materials that can be applied and are difficult to implement.

Furthermore, such methods only allow the wall thickness of the coating to be varied if this is done very carefully or has been applied by sequential steps. In addition, the variation is very difficult to precisely control the thickness of the applied layer, e.g. for the production of interrupted coatings, such as strip-shaped coatings (either in axial or running in the circumferential direction), which are separated from one another by areas where there is no or only a thin coating is located. i

I Further difficulties arise when the opposite ^;

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was written as it was first formed, then in ■

its dimensions should be changed, for example to:

using a process that involves heat and / or pressure,

calls for making heat resilient. If such a \

Processing is necessary, it's because of the nature and the!

Arrangement of the applied layer is essential, the opposite;

stood warm before or after the application of the layer!

to be able to work. ' !

j

The invention relates to a method for production llo of a hollow body, the wall of which is at least partially e.i.x. Laminate contains at least two layers by extrusion;

! man j

from the melt, which is characterized by the fact that / a!

preformed still liquid mass ("parison") from facilities extruded which provide at least two coextruded layers and independently vary the wall thickness of the layers. One layer can have a constant extruded wall thickness or both layers can be varied; it;

ι the centering of the walls can be varied, i.e. by shifting one wall to the other or simply j by increasing or decreasing the thickness of the annular gap over time. ;

The invention also relates to a device for carrying out the method, which is characterized by an extruder having a first outer die and a first outer mandrel, many having a first nozzle orifice form and which move relative to one another for the purpose of varying the cross section of the first nozzle during operation! are borrowed and the one further inside the first cathedral; having second inner mandrel, the inner wall of the : j3o sten doms acts as second inner die and second die,

and the second mandrel form a second nozzle opening and for the purpose of j variation of the cross section of this second nozzle opening are movable independently of one another during operation. The \ changes of the cross section of each nozzle opening during

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I operation will be advantageous in a predetermined series sequence, which in turn is variable. The Eri

The invention also relates to a device that includes an extruder

! as well as facilities by means of which the independent; 5 Relative movement of the dies and / or mandrels for variation j of the cross section of the first or second nozzle or both. I.

The invention further comprises a hollow body, wherein at least a part of its wall, contains a consisting of at least two layers ιIo laminate, which ren after the procedural \ or has been produced by the apparatus of the invention.

It is preferably an object produced by blow molding. In this case concerns The invention also includes a device which also includes a mold and associated devices by means of which a parison ('"parison"') expands in the mold i can be, in particular devices for the injection of

flowing media, especially gas, into the mold. Form 2o advantageously has two separable halves and is relative

to the extruder stored in such a way that during operation ^[ . the blank is trudged between the separated halves of the mold ex-I, whereupon the halves are then brought together I (the extrusion can be interrupted at this point); Gas, usually air, is injected into the soft parison within the mold to expand it against the walls of the mold. The shape and method of blow molding are conventional and therefore will not be described in detail. However, when ver; In the blow molding process, different parts of the molding are expanded to different extents, so that in the molding obtained the relative wall thicknesses of different parts differ from the relative wall thicknesses of corresponding parts of the molding as it was extruded from the nozzle head

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could differ.

The thickness of each layer of the wall can be varied by changing the relative positions axially or longitudinally the corresponding die and the corresponding dome are effected, which in this case for the purpose of training j an annular nozzle opening of increasing (or decreasing) Width with axial movement are formed by tapering off at different angles.

^! Alternatively or at the same time, the wall thickness of various segments of the annular nozzle can be determined by relative rotation or by lateral placement of the corresponding mandrels and tools; trizen can be varied. If there are zones of greater or lesser wall thickness in selected areas of the molding

If you want i15, die or mandrel with segments can versej hen who are made to move away from the stream as it happens! to withdraw from the melt or to advance into it.

j jump, doing this movement in the same way as

the lateral, rotary or axial movement is controlled 2o, as indicated below.

i The process can be used to manufacture objects that have more than two layers or layers

Containing more than two materials by using an extruder j with more than two concentric die / core assemblies ! 25 is used.

The method according to the invention is applicable to all : Extrusion materials applicable, especially thermoplasti-J see materials, and is particularly suitable for the production of ι objects that are made heat-resilient the should. Such objects are often used for coating or wrapping documents of irregular shape that have sharp corners or protrusions

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the heat-recoverable object must correspond in its shape. Such objects are difficult to coat in a freezing manner, since the stress resulting from the distortion in the case of the different degrees of restoration required in the neighboring areas can cause the object that is capable of heat recovery to split. This would normally: require a thicker-walled item, .'as ·; naturally requires more material and a longer time for heating to the reset temperature. With the Ver ^: Io, go according to the invention, however, the wall thickness of the! I end product only at the desired point through a supply ^; i enlargement of the nozzle opening between the suitable (usually the outer ¹ ) die and the corresponding mandrel ι

i,

J magnified. i

i ■ I

jl5 Often it is desired and is equally important '

; viewed, provided heat-resilient objects in different 'areas with different thickness for the inner coatings to j, for example, from a Heißschreelzkleber, eineir. Putty.

or a layer of a material (e.g. a thermo-plastic) which disoerated in the layer

Contains particles that e.g. against electromagnetic inter-, ι 1

j shield reference (EMI). A thermoplastic layer with a dispersion of silver particles is particularly suitable. Such a layer is naturally expensive and it is therefore important to apply it only to those parts of the object which contain the appropriate part of the base, e.g. that part of a cable from which the shielding had been removed to form an end termination or a brine duct. It is important, however, that all such areas pci. be coated equally well. By the method of gemä2 _'r invention, the dispersion of the object can be applied in a controlled thickness on the right parts.

Examples of such articles are heat-shrinkable ones Pipes with a layer of a heat-fusible '! A-

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materials »e.g. a thermoplastic polymer or e ; Hot melt adhesive mentioned on the inner wall. The Die?

the viand can vary along the length of the pipe in any gev; our.te: way; For example, the thickness can be cyclic / cn • 5 cheesecloth or a very low value up to a :; Maximum and j vary back to zero or the low value, whereby · lurch: tubes are obtained, which according to the cycle in parts _; or multiples thereof can be cut. The increase and decrease in thickness can be sharp or all-round; For example, as noted above, certain lining materials are expensive so it is economically important to avoid the use of an inner layer where it is not necessary Using the invention, pipe lengths can be cut that are either

have an inner layer or where, depending on the requirement, this is missing. With the help of the invention, materials I according to GB-PS 1.033.959 with an inner fusible layer _: which is integrally connected to an outer heat-shrinkable layer 12ο and the inner layer has a thickness profile gerr.ä.3

j has every desired program, simply »quietly

be asked.

i It is therefore possible to use heat-shrinkable pipes with continuous

! small or interrupted adhesive tapes are produced;

■ 25 the adhesive is usually in a heat shrinkable applicator

I withstood, but can if desired at the same

■ Time at which the part that is subsequently heat-relocatable

is made, is networked, is weakly networked. {

Finally, according to the invention, an object can be produced 3o, which is made up of a material which gev: isse Has disadvantages (e.g. from a ethyl acrylate rubber, v; e! .-

It is difficult to make flame-proof), but otherwise has good properties, e.g. full resistance to a coating or a uni: layer, e.g. a chlorosulphonite

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λλ

ι polyethylene, which overcomes the problem.

Laminates can also be made of a high creep voltage resistant material with e.g. an inner layer made of semiconducting Material can be made with the desired! i 5 Shape of the object by controlling the wall thickness at i ; the extrusion of the moldings is generated. In a similar way a material with good mechanical properties, e.g. a polyurethane, can be coated with a material which j can easily be made heat-recoverable in order to ! Io heat-shrinkable article having a desired property range to manufacture.

j The procedure is particularly applicable to the double,

> Extrusion of two layers, their melting temperatures

ι are different, e.g. for the application of an interior i

I15- coating of a hot melt adhesive with a melted '

■ temperature »which is higher than that of the outer layer, which

i then crosslinked and rendered heat resiliently v ^r ill. ■

The invention also relates to a heat-resilient hollow body with a coating or a lining which i j2o produced according to the method according to the invention j

i ι

i are. S.

The invention is explained below by way of example with the aid of the drawings:!

i Figure 1 shows an axial section through a form of a DU; 25 sunk head according to the invention.

¹ Figure 2 is a cross section taken along the line 2-2 of Figure 1

I 'Figure 3 is an axial section through the central part of the I. Head of Figure 1 showing further details.

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₁ Figure 4 is an axial section through a double-layer mold made in accordance with the invention. :

i.

; In the drawings, the extrusion head 2 has an in all-; common cylindrical body 4, a jacket 6 with a

I 5 open top and a core 8 on. The core 8 is in; the body 4 supported by a spider 10, while the ^overall: housing is secured i 6 at the bottom of the center punch 4 by a ring 12th The outer part 9 of the inner housing 6 expands

^: tert itself outwards. ,

Io The spider 10 is i with a plurality of in the longitudinal direction ; device extending passages 14 and a radial passage 16j 'provided, which is provided with an inner annular recess 1φ

communicates. The body 4 has a radial channel , 20, the inner end of which and the outer end of passage I.

I Γ

15 16 fit together exactly. !

! . ■ I

; In Figure 3, the core 8 is slidable on the spider 10 mon-: j benefits and has a generally cylindrical portion 22; 'on, in the lower end of which a mandrel 24 is screwed,!

t;

whose outer part 25 is conical at a smaller angle I

2o tapers as the housing part 9 expands. The thorn [

itself is hollow and has an expanding open end I.

i with a frustoconical side wall 26. The mandrel has j

j an upper radial wall 28 with a central nozzle opening j

30 and a plurality of longitudinally extending

25 the passages 32. The part 22 has a multiplicity of radial openings 34 and, above it, a radial end 36 with a central opening 38, the diameter of the radial openings 34 being smaller than the length of the depression 18 in the middle of the core 8.

the core mounted j and extends through the Düsenöffnun-: i3o A pin 40 with an enlarged head 42 ^within. gen 30 and 38 of the mandrel and the cylindrical part and

L - - can be found here in the_Gleitsi £ z ~ - - -

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INSPECTED

A compression spring 44 (or a plurality of spring seals - "* n" - is disposed between the head 42 and the upper surface 4c of the wall J> 6. The upper end of the hollow body part 22 is formed by a part 48 with an internal screw thread .

A mandrel 50 is mounted on the lower end of the pin 40 screws whose outer wall has a larger cone angle than

the inner wall 26 of the dome 24 has. The force of the spring ¹ 44 is just enough to close the nozzle opening between the V; änilo the 26 and 52 «

I t

ί:

j The upper end of the nozzle body 4 is provided with a central j

i - ί

i opening 52, the upper part of which has a thread 5 ⁱ⁴ ·! shows. In operation, the head 2 is on the (not shown ¹ !

! Screwed on the extruder, on which a fastening ring 56 rr.it- ■ 15 by means of screws that go through the openings 58

; ■■ has been. An annular guide plate βθ is located between the ring 56 und.der spider 10. In operation this is _; outer end of the passage 20 connected to a supply source of thermoplastic material (not shown, while i2o a mold (not shown) is located below the head 2: ¹ ;

Likewise, the core 8 is in operation by the screw; thread 48 connected to a (not shown) shaft

^! showing the relative positions of the mandrel 24 and the nozzle housing *

! 25 ses 6 can be changed. The shaft can be

] direction of the type described in US-PS 3,712,772

• be controlled.

I Thermoplastic material enters the nozzle head during operation

2 from the extruder through opening 52, goes through the 3o spider 10 through openings 14 and through the annular gap between the mandrel 24 and the housing 6.

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rial also goes through the channel 20, the passage Io and -lie recess 18 into the openings 34 of the core, from where it passes through the openings 32 and then between the '..and each other. 52 to 56 of the mandrels 24 and 50 exits.

The axial position of the mandrel 24 within the ^ eh ^ ^nes: - which bestirnt the outer wall thickness of a Pormlings, Veir · the different angles of the walls 9 and 25, a variable

Nozzle width be: 'delivering axial movement, is by Beve- ^: 8, ■

generation of the nucleus / ^ i '; part of the facilities described above changes.

Since the recess 18 is larger in length than the diameter -

If the openings 34 are, the interior of the core 1 ° is always in connection with the passage 16, so that a continuous flow of (inner: ¹ : thermoplastic ¹ material ¹

ä15 in all positions of the core 8, which are used to vary the Strength of the outer wall used is achieved.

^; In the present embodiment Horn the position of is: mandrel 50 in the mandrel 24 is determined by the relative Krä ^ e, '- ■ o plastics through the hydrodynamic pressure of the flowing Ther ^ o- \ and the spring applied 44 to the pin 40? will. - A simple on / off switch that can be operated by hand or by a-! A timer is controlled to ensure sufficient (or insufficient) strength of the material, ^ r. to overcome the spring force, two positions for the inner die (open or closed) are provided. The thickness of the inner wall can alternatively be controlled by means of devices similar to those used to control the area of the outer wall. In the case of such a design, the outer control shaft is replaced, for example, by a tube through which an inner control element fastened to the pin 40; v / elie leads, and zv: ei independent control facilities, zh

• how beschrifcbaa in the US P3 .werden to control both wall thicknesses vervenclet,

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By housing and mandrel are slightly oval in shape and the core is rotatable, the wall thickness of various portions of the radius can be of the parison again using ^"r lhn- _(Licher control means by rotation of a may be varied relative to the other. This can also be by lateral movement of the Core; the wall thickness of the inner layer can be varied in a similar way.

Similarly, either the outer housing or the inner ^: mandrel can be segmented so that portions thereof can be inwardly or outwardly ^;

■ lo vward to be moved for the purpose of producing thinner wall areas can. These controls can be varied independently of each other and the variables described above, where number4 rich different types of double wall form ingen which all fall within the scope of the invention.

| l5 4 shows a Kaope which has been using procedures and Vorrich- ■ the invention tung formed. ^ü ie cap v / eist a 'tubular portion 70 having an open end · 72, while the other end 74 adjoins the narrower end of a gene kegelstumpfförmi4 part 76th The other end 78 of the part ⁷ 6 is ^s . ', 2o closed by an end wall 80, the surface of which represents a section of a spherical surface. In the area ; j of the open end 72, but separated therefrom by an uncoated part 82, the inner wall of the tubular part 70 has an adhesive layer 84. ■ \

i

The cap is made by extrusion of a sufficient length of; Material forming two caps and a connecting length formed between the open end 72 of two open-ended caps in the mold, wherein the uncoated connection length serves to accommodate the blow needle in the blow molding stage. The wall thickness the material of the outer layer of the molding can be varied during the extrusion, so that after the stretching step its wall thickness, as shown in Figure 4, is constant

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1st or she can become a final according to any other program Wall thickness, which varies as required, can be changed.

Using the method and apparatus of the invention, the inner adhesive layer 84 can be incorporated into the final product as desired to be ordered. In the embodiment shown?: Eist: the area 82 of the tubular part 70, the open Closest to the end of 72, no inner coating is applied. Man j recognizes that in the extrusion carried out according to the invention: -Io sfonsverfahren a connection length from outer layer free can be made from an inner layer 84 and that open end 72 of the final product is supported relative to layer 84 such that the length of region 82 is any desired * te length including zero.

"5 In a particularly preferred embodiment, the outer layer 70, 76 and 8o of the article acc figure ^ is prepared from a low density polyethylene with einerr. Ru3gehalt of about 2%. The inner layer 84 includes a ■ hot melt adhesive, for example, an unsaturated polyamide (for example i ο Versamid®. |

ί

ι The total length of the cap produced in this way can ^;

! for example 100 mm. The zone 82 of uncoated. Material can have a length of about 5 ff, m. The length of the layer 84 can be approximately 25 mm, its thickness

2'5 about 0.5 mm, while the wall thickness of the tubular part _: 70 about 1.0 to 1.5 mm and the inner diameter about 18 rare.

• amount.

After blow molding the article to cross-link the outer layer, but not the inner layer is irradiated yO (for example, at a dose of 20 Mrad ^ and then to an inner diameter of 50 mm expands to 60th

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The cartridge produced in this way can be attached to one end of the cable. and be shrunk to this against mechanical -'er to protect interference, the layer 84 taking care of the cable seals the entry of moisture.

'5 Further objects constructed according to the invention k'i.' ^. E

^: e.g. for the wrapping of coiled conductors to the Abso '-. Vj

^; of connections or for sealing faults therein. The wall thickness of the outer layer can vary

^{: be} reasonable or essentially constant, while the Ir.

<lo layer can be formed from a v / and thickness that is

'in sync with the slope and the amolitude of the variation

'changes in the outer diameter of the pipe. In this way

I can apply an adhesive layer of suitable thickness on

¹ nete way on the sinuous or curved outer. Upper

= 15 areas of a line or a cable can be arranged.

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OMGlNAL INSPECTED

Claims (1)

Patent claims [I) Method for the production of a hollow body with a \ y \ ^>! ZrA, which consists at least partly of a laminate of venigsr.ens two layers, by Schrie V.; extrusi --- r., characterized in that a molding is extruded at least two layers the thickness of at least one of the extruded layers varies independently of the wall thickness of the other layer or layers. 2 "Method according to claim 1, generally also fekennselohnet, da'3 a layer of constant hot thickness is extruded. -ο 5 ^λ A process according to claim 2, characterized in that the outer layer is extruded with a constant thickness. 4 ^N A method according to claim. "Ί to 3» characterized :, that the wall is annular and the wall thickness by 'hange of the inner or outer diameter varile't O. 5 ^ A method according to claims 1 to J>, characterized geker-r.rielchnet · that the wall thickness .'and by .seitliche Relativbewegur.p zvrscu ^ a wall and the other 'is varied. 6) Method according to claims 1 to 5, characterized in that ο that the extruded article after the blow molding is subject to. T ^ The method according to insorUchen 1 to 6, characterized in that oe ~ extruriierte "erinstand below yernet? · Is. ^: ? "e".:. :: "^ t-. - ^ r: h -'- nspr'lcr-jn 1 to 7, aar-rch gekenr: ^ =: '2 ^V re, ·'■>Ινα", -. '. ei'ex η erased bla ^ verforr.ite and networked 0- &ger.F>t3'. Ai - \ '- \ ί-: ^T ,; är-r: erüci-: is made capable. 709821/0926 BATH ORIGINAL a. 9) ".'er according to claim 1, thereby fir ^ er-nzei '- ^ r ^ *, -'s
the melting temperatures of the layer materials -: ez '■ ... \ i differ from one another. 10) Device for carrying out the method, ■: * &> -. ::. e '; ■: ■ net through an extruder, which has a first outer - ■ ··· -: .- and a first outer mandrel, the eir- _; ? r: tI ^ üsencffnunp form and each other during the Betri '.- io re ~ .z ~' for the purpose of varying the Querscnnltr: ·> .- e - * --- Düser.Vffnang bev-eplich are and the inherent ^ nelb a ^ ~ ^c, - has a dome s η second inner mandrel, τ ^ ei · "T :: NEN of the first and second inner dome ^as:.: r: r ι
and the - '/. ieite Γ-' matrix and the second mandrel eir.e: -: -. *: ■
Form nozzle opening and independent ^ ii ⁷ ; relatively slow. ^; · - ^Λ - r
during operation for the purpose of variation; of the cross? ■ - / -.... t ^ of the second nozzle are movable. 11 ) Device according to claim 10, characterized by frekennzei - ':' - r. ' ~ \, - - the cross-section of a nozzle opening through is "Ii er.- '- * i tive movement between die and core change ν s *. 12) Device according to claim 10 or 11,
net, 5a3 the cross section of a nozzle ^: relative axial arrangements of "-" atr: zs and Z) """. ■ ϊν- '. are, with the die and mandrel having different 7s '" ■ ".r ^ .n or Hrv / eite ^ ungsv.'winkel and the Axia _: ^ -: ■ ■? ..- 1 ..r varies with the width of the annular gap. 13 ^ Device according to claim 10 or 11, characterized in that the cross-section of a nozzle by means of relat ,,. . «= · - · ¹ ^ - tation between die and mandrel is variable. 14) Device according to claims 10 to 13, characterized in that gz's -.'- iv. ^ I net, da.3 die or mandrel segments with retractable ". 709821/0928 BATH ^Ν Device according to claims 10 to 14, characterized by a control device for varying: ces cross section of at least one nozzle opening during operation. ^N device according to claims 10 to 15, characterized by a shape and means for ExDandierung a preform in the mold. ) Device according to claim 16, characterized by eir.e Device for the injection of flowing media. 709871/09