PVC-free multilayered tube for medical uses, method for its manufacture and use

The invention relates to a PVC-free multilayer tube for medical purposes according to the preamble of claim 1, a method for Preparation of such PVC-free multilayer tubes according to claim 16 and the use of PVC-free multilayer tubes according to the invention.

Regarding the prior art, the<dl tsize="15" compact="compact"><dt>WO-A-92/11820</dt><dd>(= D1),</dd><dt>DE-A-28 31 034</dt><dd>(= D2),</dd><dt>US-A-4,948,643</dt><dd>(= D3),</dd><dt>EP-A-0136848</dt><dd>(= D4),</dd><dt>DE-PS 44 04 041</dt><dd>(= D5)</dd><dt>DE-OS 42 19 071</dt><dd>(= D6)</dd><dt>DE-OS 39 14 998</dt><dd>(= D7),</dd><dt>WO-A-93/23093</dt><dd>(= D8),</dd><dt>EP-A-0564206</dt><dd>(= D9)</dd><dt>EP-A-0533493</dt><dd>(= D10)</dd><dt>US-A-5,520,975</dt><dd>(= D11) and</dd><dt>US-A-4,929,479</dt><dd>(= D12).</dd></dl>called.

PVC-free materials = Non-PVC materials and derived ply Tubes having only one layer are known, for example, from D1. Herein presented a hose material for medical purposes, which blend from Polyurethane and polyester has both and a sterilization treatment may be subjected in the autoclave, heat-sealable and with RF energy sealed- and is fusible. The described Tubing is free of the PVC plasticiser DEHP, a phthalate, which is to be suspected to have carcinogenic properties. It However, optionally containing a softening substance certain additional shares of Citric acid ester (Butyryltrihexylcitrat) and other processing aids such as internal or external lubricants. The method disclosed in D1 thermoplastic Although plastics material may by known molding methods such as Extrusion, injection molding or blow molding to be processed is in the but essentially for use with medical bags or thought connectors from PVC. Only in conjunction with these "classic" PVC materials, it shows satisfactory compatibility, particularly in the Compound formation by hot or high frequency sealing.

Also from the D2 are of PVC-free plastics materials known to Production of tubes for receiving or channeling blood or medical solutions are suitable. Subject D2 are particularly Plastics materials, consisting of 10 to 40 wt .-% of a substantially from Propylene units formed polyolefin, 40 to 85 wt .-% of a Block copolymers composed of a central polyethylene or Polybutylenblock with terminal polystyrene blocks, 10 to 40 wt .-% of a polymeric Plasticizer based on polyethylene, and optionally a Antioxidants exist. The materials disclosed are indeed flexible, quite heat resistant, possess for medical applications required softness of the material and can also substantially Aging problem caused by low molecular weight plasticizer largely solve the stability and rigidity of the material can, however, to desired. In particular, would the single layer material shown a Increasing the rigidity by increasing the polypropylene share at the expense the softness and flexibility of a finished tube or bag.

Multilayer tubes for medical connection lines Subject D3. Shown are three-layered tubes, whose outer Layer on ethylene vinyl acetate (EVA) and the inner layer Polyvinyl chloride (PVC) based. Since the adhesion between the inner and outer Layer is deficient, a bonding layer of a will to Ethylene based polymer containing vinyl acetate and acrylates, as middle layer together with the other two materials are coextruded. Plastic materials having the sequence illustrated, the layers are especially for use as a terminal or connector or hose with medical bags made from EVA (compatibility of the outer Layer to the bag) and then allow the introduction and secure connection, for example, by solvent fusion, a PVC membrane tube within the fitting or -rohres. For in D3 shown multilayer tubing is medically consistently to materials of concern, since the PVC layer as a plasticizer having significant amounts of trimellitic, these compounds but may be carcinogenic.

From D4 one finally knows multilayer tubes that as a potential Replacement for PVC hoses are regarded in the medical sector. However, the use of PVC according to the D4 is not entirely excluded, but it is as the material or additive for Interlayer or the inner layer well tolerated.

Specifically, the D4 relates to a three-layer tube for medical Purposes, the inner layer of ethylene-propylene copolymer, an Polypropylene, a copolyester from a polyether and a Polyethylene terephthalate, polyurethane, polyvinyl chloride or a blend of Copolyester and ethylene vinyl acetate copolymer.

The intermediate layer may be made of LLDPE (Linear Low Density Polyethylenes), ethylene-vinyl acetate copolymer (EVAC), modified EVAC, Ethylene-methyl acrylate copolymer (EMAC), modified EMAC, PVC or a blend of the aforementioned compounds.

The outer layer according to D4 is made of polypropylene, ethylene-propylene copolymer or modified ethylene-propylene copolymer formed.

The selection of materials for the intermediate layer depends in essentially on the ability of these materials to the entire structure of the to impart the necessary flexibility multi-layer pipe. The criterion for the selection of the inner layer material is a sufficient heat resistance, to make the resultant tube autoclavable while the Choice of an outer layer material at substantially the desired orientation, a relatively resistant ultrasound, hot or high frequency energy sealing to allow a polycarbonate connector.

Apart from the fact that the tubes in accordance with the use of PVC D4 not completely rule out, the hoses are indeed with polycarbonate tolerated, but less to connect education with other recent and more advantageous based on polypropylene bag or Connector materials suitable.

In addition, the flexible middle layer according to D4 is usually the most layer, which slightly too low rigidity of the entire hose brings with it. It is a rule and not only optionally necessary to irradiate extruded tubes to by radiation-induced Crosslinking to cause Hitzesterilisierbarkeit. This operation is consuming.

The D5 betrift polymer material of medical instruments. silangepropfte Disclosed VLDPE's or ULPDE's the moisture were linked to then as transparent and kink-resistant and obtain sterilizable tubing, especially d hrough extrusion. Height Crosslinking levels are a prerequisite for autoclavability of the final product. Although the material seems suitable for replacement of PVC, lacking from available single-hoses on the ability of a Fitting a good and direct connection during a simple to respond heat sterilization treatment, without the dimensional stability have to give up.

The D6 discloses strahlensterilisierbare recyclable infusion and Transfüsionsgeräte in which all components of thermoplastic or elastomeric homopolymers, copolymers, block copolymers based on are shown polyolefins. In particular, the public makes D6 Connecting pipes, LLDPE or from linear PE LVLD accessible, but excludes the use of EVA or ionomers not specific.

For connecting these tubes are using organic Solvents such as cyclohexane added. Alternatively, let the tubes Ultrasonic welding or by light or UV-curable adhesives connect.

D7 is concerned with transmission systems for Infüsions- or Transfusion, in which the environmentally sound recycling all Constituents of a polymer, copolymer or block copolymer under Eliminating PVC exist. The polymer materials which find use, based on styrene polymers.

D8 relates to PVC-free coextruded multilayer tubes for medical Purposes, a core layer of a blend of polyamide and EVA exhibit. On this inner core layer is an outer layer by means of a Adhesive layer applied. The adhesive layer has essential copolyester and SEBS copolymer on, optionally PP and EVA. The choice of material is that the disclosed tube must have the disadvantages resulting from the use resulting from EVA, copolyester or polyamide.

The D9 concerns medical devices with a single- or multilayer Construction. Disclosed are structures inside a and an outer layer , between which must be a further intermediate layer. All Layers include crystalline polyolefins, while the intermediate layer additionally required to have an amorphous polypropylene. In addition, the D9 discloses Structures, which consist of a layer which at least one crystalline comprising polyolefin and amorphous polypropylene.

Crystalline polyolefins according D9 are iso- or syndiotactic polypropylenes or a copolymer based on isotactic polybutene-1 or a isotactic copolymer based thereon.

Amorphous polypropylene is atactic polypropylene or a thereon based copolymer.

The intermediate layer (for 3 layers) or a layer of single-layer Structure, in addition to the mixture of crystalline and amorphous polyolefin additionally comprise an amount of a thermoplastic elastomer.

D10 from the laminated films are known which comprise a layer (A), which contains a resin composition comprising 20 to 100 wt .-% amoprhes having polyolefin and 80 to 0 wt .-% crystalline polypropylene; and a an outermost layer (B) comprising a crystalline polypropylene, a Ethlyen (co) polymer or a crystalline polypropylene and a polar Ethylene (co) polymer.

D11 discloses multilayer films for medical applications with internal, outer and intermediate layer, all the layers predominantly polyolefins based and the inner layer from a mixture of Ethlyen-α-olefin Copolymer with φ = 0.930 to 0.945 g / cm³ and a polypropylene, the Middle layer of a mixture of a Ethlyen-α-olefin copolymer with φ = 0.920 to 0.945 g / m³ with a Ethlyen-α-olefin elastomer with density φ = From 0.880 to 0.890 g / cm³While the outer layer of an ethylene-α-olefin copolymer with a density of .930-.945 g / cm³ is formed.

D12 finally relates to a medical bag made of a Laminate is composed, which has a lower inner layer of a polyethylene Density, an intermediate layer of EVA, EP elastomer or Ethlyen-butene-1-elastomer and an outer layer of PE comprises low density.

In view of the drawbacks with which the prior art set forth in the Described embodiments are afflicted, it is an object of the present Invention to provide a tube for medical purposes, the individual adaptation to many different, and in particular polypropylene or polycarbonate-based by connectors or bag materials allowed. Further, it is desirable that the new tubing a fixed Bond without additional adhesion promoter or the like is possible. additionally is the new multilayer tube be sufficiently flexible, elastic and soft and yet as little as possible knickanfallig, relatively dimensionally rigid and thermally stable be. Finally, the tube is in contact with the usual in medicine Fluids give off no harmful substances in these fluids and ever be inert towards medical solutions. The aim of the invention is In addition, a method for producing such a multilayer tube specify. Furthermore, the statement of uses of inventive hose material object of the invention.

These and other unspecified objects are achieved by a non-PVC Multi-layer tube for medical purposes, of the type mentioned with the features of the characterizing part of claim 1. Special Further developments are in areas dependent on claim 1 claims placed under protection. In procedural terms, the invention Object is achieved by a method according to claim 16, while the claims 19 to 21, the use of PVC-free inventive Protect multilayer tube.

Characterized in that in a PVC-free multilayer tube for medical Purposes with at least two layers of which a base layer A) made of a first plastic material having at least one connection layer B) of a second plastic material is connected, the first plastic material to the predominant part of a synthetic rubber or isoprene-based Polypropylene with a density ρ ≤ 0.9 g / cm³Which heat sterilization at a ≥ 121 ° C without damage form survives, a Shore D hardness ≤ 32, has the case ≥ 121 ° C a has residual stress sufficient to provide a connection point to a to form Preßssitz, so that the base layer A) at temperatures of ≥ 121 ° C even is dimensionally stable, and from a squiggle or a loop with a diameter can be formed of up to 60 mm without kinking, while the second Plastic material for the most part, a polyethylene copolymer,    or a synthetic rubber with M_w is &lt;100 000. g / mol, which at during a heat sterilization at 121 ° C under the Forming an interference fit resulting Konnektionsdruck tends to flow and a hardness Shore A ≤ 65, such that each connection layer B) at a temperature of 121 ° C under Konnektionsdruck not its shape, it is possible a flexible hose, the after heat sterilization is transparent, of sufficient having kink resistance and the like with hose clamps or is sealed to provide. In addition, the inventive PVC-free multilayer tube in addition the ability to a built-in part, a medical bag or a connector fixed enter into and tight connection, and certainly very easy for a possible heat sterilization treatment.

The present invention is therefore, inter alia based on the idea different plastic layers in a multilayer tubular material so coordinate that at least one layer acting as a base layer the tubing sufficient thermal stability during sterilization gives, while at least one other layer or Konnektions- Link layer acting, the formation of a solid and dense Connection with a bag, hydrants, connector or another Hose allows without additional adhesive, sealant or Sealants or aids would use or other apply sealing process (high-frequency energy or the like) would.

Within the scope of the invention is given inter "sterilization" is generally a A method for killing or inactivation (viruses) of all microorganisms including highly resistant persistent forms understood the Hoses invention in particular a steam-sterilization Autoclaves with pressurized steam of at least 121 ° C, corresponding to about one atmosphere pressure, the so-called autoclaving or taking autoclave treatment without damage to resist.

Furthermore, in the invention, "plastic material" such understood materials whose essential constituents of macromolecular consist organic compounds, wherein the plastic materials as Polymers are referred to, including in particular homopolymers and Copolymers (random, block and / or graft polymers) and mixtures (= Blends) of the aforementioned substances include.

An important criterion for selection and assignment to the invention a polymer to a plastic material and thus to a certain Functional layer of the multilayer PVC-free tubing for medical Purposes, the dimensional stability is during the heat sterilization.

A plastic material in the above sense as a dimensionally stable when a Tube sample of at least 10 mm in length, an inside diameter of 5 mm and an outer diameter of 7 mm, a hot steam sterilization at 121 ° C with at least 15 min. Warm-up for at least 15 min. Hold time, and at least 10 min. Cooling time without optically visible change in shape as "Collapse" or "ovality" etc., survives.

The temperature for the softening of the polymers according to the invention or plastic materials of interest, is the temperature of the Steam sterilization, namely 121 ° C. Characterized in that the base layer comprises a polymer having its dimensional stability so temperature stability with respect Deformation is given even at more than 121 ° C, the possibility of flowable or softening of reaching the liquid state of Base layer largely excluded during steam sterilization, while a polymer of the plastic material of the connection layer whose flowable Softening is achieved under molding pressure at 121 ° C the softening of the Connection layer under the standard conditions of steam sterilization permits. This is at a contact point with a connection partner connect to this possible without the shape of the tube is uncontrolled changes.

The temperatures are based in each case on the pressure at steam sterilization, ie about one atmosphere pressure. It is understood however, that the pressure dependency of the softening temperature in consideration Range between the necessary and normal pressure for steam sterilization Overpressure in general is negligible.

Depending on the function of the non-PVC hose of the invention, it can be beneficial, specifically qualified to compound forming layer B) outside, to arrange the inside or the outside and the inside. is Accordingly, the PVC-free multi-layer tube of the invention, preferably by the sequence of the layers B) A), A) B) or B) A) B), in each case from the inside to the outside, in.

In the first case example, the hose according to the invention such. A connector be "plugged" from a suitable material so that the inner layer of the Tube with the outer surface of the connector is in contact. in the the second case, the tube according to the invention for insertion into a hollow part thought, the inner surface of a suitable material for forming a Connection, while with arrangement of two connecting layers (Interior and exterior) in the inventive PVC-free multilayer tube said two connection options selectively or simultaneously be realized. Preferably, in a compound with the connector Kennektionsschicht inside while at a compound such as a Bag the connection layer is outside.

In addition to the basic and Konnektionsschichten described so far has the PVC-free multilayer tube of the invention in a preferred Continuing through another functional layer, namely, on addition at least one transparent cover layer C) as an outer layer of a third plastic material, a layer C) as the innermost or outermost Layer may be disposed.

The outer layer provides the multilayer tube improved Finish regards tackiness, dullness and reduced friction, transparency and special sealing property.

In principle, the layer C) can be used as finishing layer either inside or be provided externally. However, it is preferred for the invention, that for the Case that the outermost or innermost outer layer is a connection layer B) is that corresponding thereto oppositely disposed outer layer a Layer C).

It is particularly advantageous at least on the top layer as a training Lipped tube (Fig. 2). Thus are inventively particularly preferred Embodiments, such PVC-free multilayer tubes by the Sequence of the layers B) A) C) / C) A) B) / C) B) A) B) or B) A) B) C), Are indicated in each case from the inside to the outside. Depending on the use of Hose must the inner layer with the current flowing through the hose be compatible solution.

In order to ensure the above-mentioned properties of the layer C) consists in a further advantageous embodiment, the outer layer C) of a third Plastic material, comprising at least one polymer whose Temperature resistance to deformation are about&gt; 121 ° C given is.

In accordance with the invention preferred PVC-free multilayer tubes is the first plastic material for the base layer for the most part a synthetic rubber isoprene-based or polypropylene having a density ρ ≤ 0.9 g / cm³ and the second plastic material for the connection layer for the most part, a polyethylene copolymer or a synthetic Rubber with Mw &lt;100,000 g / mol. This combination for each base layer A) and the connection layer or layers B) may already be a variety of required properties offer. is particularly advantageous for the invention a polymer used according to the following list. percentages each represents percent by weight.<dl tsize="14" compact="compact"><dt><u>topcoat</u>:</dt><dd>Thickness = 10 - 50 microns</dd><dt>40% - 60% PP-R</dt><dd>(PP23M 10 cs 264, REXENE) and</dd><dt>60% - 40% SIS</dt><dd>(HVS 3, Kuraray); or Tuftec H 1052 (Asahi)</dd></dl><dl tsize="13" compact="compact"><dt><u>base layer</u>:</dt><dd>Thickness: 900-980 microns at about 1 mm wall thickness of the tube</dd></dl><dl tsize="19" compact="compact"><dt>50-100% SIS</dt><dd>(HVS / 3, Kuraray) and</dd><dt>50-0% PP-R</dt><dd>(PP 23M10cs264, REXENE); - PP with Shore D ≤ 32, Q = 0.9 g / cm³; (For example, Adflex 100 G, Himont, with up to 50% rubber content, for example, PIB, styrene-ethylene-butylene rubber, Styrene-ethylene-propylene rubber, SIS) </dd><dt><u>connection layer</u>:</dt><dd>Thickness 10-50 microns</dd></dl><dl tsize="22" compact="compact"><dt>100% SEBS compound</dt><dd>(PR 3415, Wittenburg)</dd><dt>100% SEPS / SSPs</dt><dd>(Septon 2277, Kuraray) or</dd><dt>50-100% PE copolymer</dt><dd>(Engage XU58.000 52, DOW) and</dd><dt>0 - 50% SEBS / SEB</dt><dd>(Kraton G1726, Shell);</dd></dl>

The abbreviations in detail:<dl tsize="14" compact="compact"><dt>PP-R =</dt><dd>Polypropylene random copolymer</dd><dt>SIS =</dt><dd>Styrene-isoprene-styrene</dd><dt>SEBS =</dt><dd>Styrene-ethylene-butylene-styrene rubber</dd><dt>SEB =</dt><dd>Styrene-ethylene-butylene-rubber</dd><dt>SEPS =</dt><dd>Styrene-ethylene-propylene-styrene rubber</dd><dt>sep =</dt><dd>Styrene-ethylene-propylene rubber</dd><dt>PE copolymer =</dt><dd>Polyethylene copolymer</dd></dl>

SEBS and SEB belong to the group of styrene-ethylene-butylene block copolymers, which in the context of the invention with advantage as Konnektionsschichtmaterialien or in the connection layer in mixture other materials each used in different proportions Block can be.

SEBS compound is a mixture of different styrene-ethylene-butylene block copolymers.

The same applies to and SEPS SEP which the group of styrene-ethylene-propylene block copolymers belong. Also, a one-SEPS Compound Mixture of different styrene-ethylene-propylene block copolymers.

Again, in view of the adhesion between the layers of the Materials A), B) and C) can be said that they generally sufficient is. However, it can be increased in an advantageous manner by the Layers A), B) and / or C) each additionally contain up to 40 wt .-%, based to 100 wt .-% of its above-described and defined having composition of that plastic material, which for Training of one or both adjacent layers of PVC-free Multilayer tube is used. Also advantageous is a further intermediate layer from the polymer materials of the adjacent layers.

Through this "material exchange" or substitution of material is the Compatibility of each other formed into a tube layers significantly increased without compromising the other properties in question.

Another essential feature of the invention and particularly preferred is the fact that, in a development of the inventive PVC-free Multi-layer pipe, the plastic materials for all the layers of the Tube are selected such that they consist essentially Polyolefin homopolymers or polyolefin copolymers or modifications thereof (eg SEBS) exist. It was particularly surprising that with the Invention for the first time possible to create a PVC-free multilayer tube, consisting solely of environmentally friendly materials, the easily connect education with connectors during steam sterilization permit and at the same time all other requirements for a medical insertable tube fulfill.

With regard to the geometry of the tubes can even in all the required and customary thicknesses and sizes to be carried out. Preferably, the inventive PVC-free multilayer tube for more than 96-98 vol .-% based on the total volume of the hose material from the base layer A). The individual layers themselves preferably have the following thicknesses: The Base layer A) has a thickness&gt; 900 microns, the connection layer B) has a thickness between 10 .mu.m and 50 .mu.m and the sealing layer C) has a thickness between 10 microns and 50 microns.

The invention also provides a process for producing a PVC-free Multilayer tube for medical purposes, in which to Generating a least two-layer multilayer film of plastic a first plastic material for forming a base layer A) and a second plastic material to form at least one connected with it Connection layer B) with each other and a substantially co-extruded coaxial and cylindrical multilayer tube formed, the method is characterized in that one uses a first plastic material, comprises at least one polymer having a heat sterilization at ≥ 121 ° C without mold damage survives, a Shore D hardness ≤ 32, has the at ≥ 121 ° C has a residual voltage, which is sufficient to at a to form an interference fit connection point, and from a kringle or Loop with a diameter of up to 60 mm without kinking can be formed while using a second plastic material, comprises at least one polymer in during a heat sterilization resulting 121 ° C under the in formation of an interference fit Konnektionsdruck tends to flow and a Shore A hardness having ≤ 65, so that the dimensional stability of the first plastic material at temperatures ≥ 121 ° C is given and that of the second plastic material is not more.

The molding is carried out by the skilled worker process, as For example, the vacuum calibration. Important for the invention is above especially that it is possible through the co-extrusion of multiple layers together, more desired properties of individual components in a tube to unite, to thereby increase the quality of the tube.

For this just provides the coextrusion the option under appropriate choice of extrusion partners customized PVC-free to provide multi-layer hoses available that it in a unique way allow to dispense with any addition of adhesion promoters and yet the required properties and additionally other important Properties such as gas and water vapor permeability, strength of Material, weldability, transparency and heat resistance of the influencing hose.

Of great importance for the invention is the selection of one another to extruded layer materials, particularly preferably Plastic materials or layers are chosen so that all the layers the PVC-free multilayer tube consisting essentially of Polyolefin homopolymers and / or polyolefin copolymers are made, or it based polymers such as modifications of polyolefins (eg, SEBS).

Co-extrusion of such materials is known in principle, it is However, due to existing experiences not readily successful Realization of such a complex multilayer tube as the the invention could straightforwardly. In this respect was the invention Success surprising because otherwise repeatedly demonstrated in practice that even with the aid of optionally tabulated properties of Polymers, such as data for bond strength, the use of such materials does not necessarily lead to success. That is, the solution of a set task by mere selection from known materials is at a multilayer Koextrusionsschlauch generally not readily possible. Thus, the tuning of the viscosity of the melt is in the Coextruding rubbers such as PIB with PP particularly difficult.

Furthermore, it is preferred in the process according to the invention in that, for Forming a non-PVC multi-layer pipe, the plastic materials so selects that all layers of the tube additionally contains up to 40 wt .-% of the may contain material of the adjacent layer or layers. This poor adhesion between two may to some extent adjacent layers are compensated. After the actual shaping the resulting tube can be further processed in the usual ways. Preferably, it is quenched with water after molding. hereby is due to the "freezing" of the amorphous state, an optimum bond with high flexibility and sufficient rigidity achieved, but especially is the shock-like cooling of the molten transparency of the hose improved because no crystalline regions can form. this leads to a low degree of crystallinity and thus to high transparency and Toughness.

The inventive PVC-free multilayer tube is Excellent for use in the medical field. The materials of the multi-layer pipe are all selected such that the hose transparent, kink resistant and flexible, but especially heißsterilisierbar and by simultaneously pressing force exerted by the tube with a is appropriate connector firmly and bacteria proof connectable. additionally is the non-PVC multi-layer hose of the invention also biocompatible. The use of PVC, which is always a proportion of plasticizers contains, is avoided and no coupling agents are needed that possibly diffuse through the layers of plastic material could.

is due to its excellent material and performance characteristics the inventive PVC-free multilayer tube with an especially large Advantage as fluid-carrying line in dialysis, infusion or artificial Nutritional uses. To this end, it is advantageously provided, that at least the terminal portion for connection to the supply bag with a weld lip is provided.

This technique makes use primarily the compatibility of Konnektionsschichtmaterials the multi-layer pipe according to the invention with the connection pieces of medical bags (especially polypropylene) and / or specially usual in medical joining techniques, for example in the form of connectors to use polypropylene. Connectors or bag may thereby provided with a rough surface be placed on the an inventive PVC-free multilayer tube is such that the inner surface of the PVC-free multilayer tube with the connection layer B) of the tube an interference fit with the rough Outer surface of the connector or bag (optionally connecting piece the bag) forms.

By the surface of the polypropylene parts and the flow property of the Connection layer B) of the tube by the action of heat at about steam sterilization is by flowing the material Connection layer in the unevenness of the surface of the connector or Bag neck where an already good and firm connection training. More preferably, the compound when the preparation of the Connection layer B) of the hose used plastic materials with a proportion between 1 and 40 wt .-%, based on 100 wt .-% of the Material of the connection layer with a plastic material from which the connector or the connecting piece of the bag there, blinded will. The link can be improved by roughening the surface will.

Further advantages and details of the invention result from the following examples, the accompanying with reference to the figures are explained.

show in the figures<sl><li>1 shows a cross section of an embodiment of the present invention PVC-free multilayer tube,</li><li>Figure 2 shows another embodiment with lip formation.</li></sl>

In the figures, you can see a three-layer tube 1 according to the present invention. The outer layer 2 of the tube 1 is at the in Figure 1 embodiment a cover layer C) of a blend of SEBS compound, SEPS compound, a PP / SIS Blend or PP / styrene-ethylene-butylene (-propylene) Rubber blend, SEBS and / or SEPS.

The intermediate layer 3 is a base layer A) the largest volume of Tubular casing. Suitable materials include styrene-ethylene-butylene-rubber with PP, PP with PIP, SEPS with PP, PP and PP with SIS.

The connection layer 4 consists of SEBS compound with SEBS / SEB (Kraton G1726 and Kraton G 1652, Shell), a PE copolymer (Engage XU58000, 52, DOW) optionally with SEBS / SEB (Kraton G1726, Shell) or SEPS / SSPs (Septon 2277, Kuraray). Kraton G1726 is a low molecular weight SEBS with 20% diblock content, while Kraton G 1652 is a higher molecular weight SEBS without call values ​​diblock.

The layers A), B) and C) in this case have the following form resistance, E-module, and curing on: <tables><table><tgroup cols="4"><tbody><row><entry align="center" /><entry align="left">Modulus</entry><entry align="left">hardness</entry><entry align="left">Dimensional stability at heat sterilization</entry></row><row><entry align="left">Main layer base A)</entry><entry align="left">≤ 80N / mm²</entry><entry align="left">Shore D≤32</entry><entry align="left">&gt; 123 ° C</entry></row><row><entry align="left">Connection layer B)</entry><entry align="left">≤ 80N / mm²</entry><entry align="left">Shore A≤65</entry><entry align="left">&lt;121 ° C</entry></row><row><entry align="left">Outer layer C)</entry><entry align="left">&lt;1000N / mm²</entry><entry align="left">&lt;R90</entry><entry align="left">&gt; 123 ° C</entry></row></tbody></tgroup></table></tables>

Further advantages and embodiments will emerge from the following Claims.