DE102009000188A1 - Multi-layer composite pipe comprises internal layer produced from a first polymer, an external layer produced from a second polymer, and an intermediate layer produced from a metal and arranged between the internal and external layer - Google Patents

Abstract

The invention relates to a multilayer composite pipe having an inner layer (1) produced from a first polymer, an outer layer (5) produced from a second polymer and an interlayer (3) interposed between the inner (1) and the outer layer (5) ). In order to ensure the most universal connection technique, it is provided according to the invention that at one end (E) of the multilayer composite pipe at least the end edges (S1, S3) of the inner (1) non-molded, formed from a third polymer end piece (6) circumferentially with each other are connected so that no liquid between the inner (1) and the outer layer (5) can penetrate.

Description

The The invention relates to a multilayer composite pipe according to the preamble of claim 1. It further relates to a method of manufacturing a multilayer composite pipe.

Multilayer pipes are well known in the art. They usually exist from an interior and an outer layer, each made of a polymer. Between the interior and outer layer a metal layer is embedded, usually made of aluminum is made. The connection of the inner and the outer layer with the metal layer is usually by means of a primer layer. The primer layer, which is also formed from another polymer can also like the inner and the outer layer be applied by extrusion. The adhesion-promoting effect the other polymer is usually based on grafted polar Groups, such as maleic anhydride. - Such Composite pipes find particular in the field of heating, for example for underfloor heating, Use.

To the Connection of a multilayer composite pipe, for example to a Fitting or a device will this provided in the prior art with a so-called "press fitting". For this purpose, one end of the multilayer composite pipe is widened and opened put the nozzle of a fitting. The following is about the plugged portion of the multilayer composite pipe pushed a sleeve and this pressed by means of suitable pressing jaws. The production Such a press fitting is relatively expensive and expensive. She does, however the advantage that the end edges at the end of the multilayer composite pipe not with liquid get in touch. It is thus in particular an intrusion of liquid in a space between the inner or outer layer and the metal layer safely and reliably avoided.

Multilayer pipes can be selected by a suitable choice, in particular that for the inner layer used polymer, in principle for many Use application areas. For example, it is conceivable multilayer composite pipes for the production of hot water tanks, as a fuel line Vehicles or the like. Use. From technical and also comes for economic reasons here the provision of conventional Press fittings for connecting or connecting multi-layer composite pipes not considered.

task The invention is as simple as possible specify producible multilayer composite pipe, which the realization a novel connection technology allows.

These The object is solved by the features of claims 1 and 13. Advantageous embodiments The invention will become apparent from the features of claims 2 to 12 and 14 to 25.

To proviso the invention is provided in a multi-layer composite pipe, that at least at one end of the multilayer composite pipe, the end edges the inner layer and the outer layer with an injection molded on it, from a third polymer formed tail circumferentially interconnected, so no liquid between the inner and the outer layer can penetrate. - The Provision of the invention by injection molding molded tail allows a permanent and thus safe and reliable sealing of at least an intermediate layer made of metal against a contact or ingress of liquid. This can be a corrosion of the metal layer and thus an undesirable Resolution of the Multilayer composite counteracted ent at the end of the multilayer composite pipe become. The multilayer composite pipe according to the invention As a result, it can also be used with alternative joining techniques a device a fitting or the like connected or interconnected become. It may be in particular that at the end of the multilayer composite pipe According to the invention provided tail in the connection state with liquid comes into contact.

To an advantageous embodiment of the invention, the tail has a overlaying the inner wall circumferential inner wall section on. In this context it is advantageous in that an inner diameter has an expansion at the end, which is about twice a thickness of the inner wall portion. An axial length the expansion is expediently bigger or approximately equal to an axial length of the inner wall section. An end piece with the aforementioned features has a particularly strong connection with the multilayer composite pipe on. Apart from that, because of the proposed expansion of the Inside diameter a narrowing of the flow cross section of the Multilayer composite pipe can be avoided. The interior section can be sprayed so advantageously to the inner layer, that a substantially stepless transition between the inner section and the inner layer results.

According to a further advantageous embodiment, the tail has a peripheral outer portion overlying the outer wall. In this case, an outer diameter of the outer portion may be larger than a further outer diameter of the multilayer composite pipe. Ie. the outer portion may be formed in particular in the form of a flange. Such a flange can z. B. in combination with a plugged onto the multi-layer composite pipe union nut forming a connecting device at the end of the multilayer composite pipe.

When particularly useful it turned out, the third polymer and / or the first polymer and / or to form the second polymer of the same material. Provided the first, second and third polymers are made of the same material are, in a particularly simple manner, a firm connection of the tail achieved with the multi-layer composite tube by injection molding become. In this case, it is not necessary in particular to Making a firm connection with the end piece compatibility maker use.

at but it can also be special requirements that, for example the inner layer forming first polymer is formed by the outer layer second polymer is different. In this case, the second and the third polymer expediently made of the same material. To make a heartfelt Compounding with the first polymer may in this case be a compatibilizer be used. Come as a compatibility maker generally polymers with amphiphilic properties into consideration, ie Polymer chains with polar and non-polar groups. It can z. B. one with maleic anhydride grafted polyethylene act.

in the With regard to the choice of material for the first and / or second and / or third polymers have polyolefins or polyamides as particularly useful.

To Another particularly advantageous embodiment is the tail, preferably on the outer section, a circumferential seal attached. For attaching the seal can for example in the outer section a circumferential groove may be provided, in the seal as an O-ring is inserted. According to another preferred embodiment feature is the seal on the tail, preferably in the 2K process, sprayed. Especially in this Case, it has proved to be expedient to form the seal of a thermoplastic elastomer. A Such seal can also in the range of a front edge of the tail or also provided as a peripheral seal on the outer portion of the tail be.

at the metal layer composite pipe according to the invention is expediently between the intermediate layer and the outer and / or the inner layer of a provided an additional polymer primer layer. The further polymer may have polar groups, for example maleic anhydride, which cause a bond to the metal layer. The primer layer (s) may as well like the outside and the inner layer is made by extrusion, preferably coextrusion become.

• a) Bereitstellen eines Mehrschichtverbundrohrs mit einer aus einem ersten Polymer hergestellten Innenschicht, einer aus einem zweiten Polymer hergestellten Außenschicht und einer zwischen der Innen- und der Außenschicht eingelagerten, aus Metall hergestellten Zwischenschicht,
• b) Einsetzen des einen Endes des Mehrschichtverbundrohrs in ein Spritzgusswerkzeug und Verschließen eines Durchgangs des Mehrschichtverbundrohrs mit einem Kern und
• c) Umspritzen zumindest der Stirnkanten der Innen- und der Außenschicht im Spritzgießverfahren mit einem dritten Polymer, so dass ein umlaufendes, die Innen- und die Außenschicht miteinander verbindendes und ein Eindringen von Flüssigkeit dazwischen verhinderndes Endstück sich bildet.

For the production of a multilayer composite pipe, according to another aspect of the invention, a method is proposed with the following steps:

• a) providing a multilayer composite pipe having an inner layer made of a first polymer, an outer layer made of a second polymer, and an intermediate layer made of metal between the inner and the outer layer,
• b) inserting the one end of the multilayer composite pipe in an injection mold and closing a passage of the multilayer composite pipe with a core and
• c) molding at least the end edges of the inner and the outer layer by injection molding with a third polymer, so that a circumferential, the inner and the outer layer interconnecting and preventing ingress of liquid therebetween end piece forms.

The proposed method allows for the first time the production of a multilayer composite pipe, which in terms of is particularly universal on the connection technology. In contrast, For example, to a dipping process, the inventively proposed allows Inject molding the production of end pieces with a predetermined contour, especially at the outer periphery. This can be contours already in the design of the tail realize which with regard to the connection technology a Fulfill function. Ie. the molded by injection molding tail can in addition to its sealing function also fulfill a connection function.

Advantageously, the molded-on end piece has a peripheral inner section that partially overlies the inner wall. In this context, it has proved to be particularly expedient, before the step lit. b) widen an inner diameter at the end. The expansion of the inner diameter can be done with conventional expansion tools. The expansion is expediently between 5 and 20% of the inner diameter of the multilayer composite pipe. It can have an axial depth of 5 to 30 mm. An expansion amount of the expansion is about twice a thickness of the inner portion. Ie. the inner portion expediently fills the expansion. This results in a continuous transition from the inner layer to the inner portion of the tail. This can in particular a narrowing of an interior Diameter be avoided in the region of the tail.

Because of the other features of the method is on the previous versions directed. The features described there can be design features in the same way of the claimed method.

following Be exemplary embodiments of Invention explained in more detail with reference to the drawings. Show it:

1 a schematic cross-sectional view of a flared end of a multilayer composite pipe,

2 a schematic cross-sectional view of the multilayer composite pipe according to 1 with end piece molded onto it,

3 a schematic cross-sectional view corresponding to a multi-layer composite pipe according to 2 with seal molded on it,

4 a schematic cross-sectional view of a non-expanded end of a multilayer composite pipe and

5 a schematic cross-sectional view of a non-expanded end of another multilayer composite pipe.

1 shows schematically a cross-sectional view through a multilayer composite pipe. In this case, an inner layer produced, for example, from polyolefin 1 via a first adhesion promoter layer 2 with a metallic intermediate layer made of aluminum 3 connected. The intermediate layer 3 is via a second adhesion promoter layer 4 with an outer layer which in turn is produced as a polyolefin 5 connected. At an end of the multi-layer composite pipe generally designated by the reference E, the inner layer has 1 an inner layer end edge S1, the intermediate layer 3 an intermediate layer end edge S2 and the outer layer 5 an outer layer edge S3 on. An inner diameter of the multilayer composite pipe is designated by the reference symbol D _i .

The inner diameter is widened at the end E. The expanded inner diameter is denoted by the reference D _a .

At the in 2 In particular, the inner layer end edge S1, the intermediate layer end edge S2 and the outer layer end edge S3 of a circumferential end piece are shown 6 surround. In the present embodiment, the tail 6 an interior section 7 on, which to the inner layer 1 is injected and extends over an axial portion A, which is provided with the expanded inner diameter D _a . A thickness D of the inner wall portion 7 is chosen so that thereby an expansion dimension .DELTA.D = D _a - D _{i of} the expanded diameter D _{a is} compensated, ie in the region of the inner portion, the multilayer composite pipe again has the inner diameter D _i . With the reference number 8th is an outer portion of the tail 6 designated, which on the outer layer 5 is injected. An outer diameter A _{1 of} the outer portion 8th is larger than an outer diameter A _{2 of} the outer layer 5 , The outer section 8th So jumps radially against the outer layer 5 in front.

3 shows a cross-sectional view of a multilayer composite pipe according to 2 , in which case at an end face of the tail 6 a molded in 2K process sealing element 9 is provided. The sealing element 9 may for example be made of a thermoplastic elastomer.

4 shows a cross-sectional view of an end E, in which the inner diameter D _{i is} not expanded. The tail 6 is here only to the end edges S1, S2 and S3 and in sections to the outer layer 5 molded. Ie. It is in the outer section 8th but not an interior section 7 intended.

At the in 5 shown further embodiment, the inner diameter D _i at the end E again not expanded. However, here is the tail 6 both an inner wall section 7 as well as an outdoor section 8th on. As a result, the inner diameter D _{i of} the multilayer composite pipe is in the region of the inner wall portion 7 narrows.

In all embodiments, it is possible, in particular in the region of the outer portion 8th to provide circumferential grooves in which, for example, an O-ring is inserted for sealing purposes. Instead, on the outer circumference of the outer section 8th Also sealing elements are sprayed in 2K process, which are made for example of a thermoplastic elastomer.

1

inner layer

2

first Bonding layer

3

interlayer

4

second Bonding layer

5

outer layer

6

tail

7

inner portion

8th

outer portion

9

sealing element

A

distance

A ₁

first outer diameter

A ₂

second outer diameter

D

thickness

D _a

widened Inner diameter

D _i

Inner diameter

e

The End

Claims (25)

Multi-layer composite pipe with an inner layer made of a first polymer ( 1 ), an outer layer made from a second polymer ( 5 ) and one between the inner ( 1 ) and the outer layer ( 5 ) embedded, made of metal intermediate layer ( 3 ), characterized in that at one end of the multi-layer composite pipe at least the end edges (S1, S3) of the inner ( 1 ) and the outer layer ( 5 ) with an injection-molded, molded from a third polymer end piece ( 6 ) are circumferentially interconnected so that no liquid between the interior ( 1 ) and the outer layer ( 5 ) can penetrate. Multilayer composite pipe according to claim 1, wherein the end piece ( 6 ) a the inner wall overlying peripheral inner portion ( 7 ) having. Multilayer composite pipe according to one of the preceding claims, wherein an inner diameter (D _i ) at the end (E) has a widening which is approximately twice a thickness (D) of the inner portion (E). 7 ) corresponds. A multilayer composite pipe according to any one of the preceding claims, wherein an axial length of the expansion is greater than or about equal to an axial length of the inner portion (Fig. 7 ). Multilayer composite pipe according to one of the preceding claims, wherein the end piece ( 6 ) a peripheral outer portion overlying the outer wall ( 8th ) having. Multilayer composite pipe according to one of the preceding claims, wherein an outer diameter (A ₁ ) of the outer portion (A ₁ ) 8th ) is greater than a further outer diameter (A ₂ ) of the multilayer composite pipe. Multi-layer composite pipe according to one of the preceding Claims, wherein the third polymer and the first and / or the second polymer are made of the same material. Multi-layer composite pipe according to one of the preceding Claims, wherein the first and / or second and / or third polymer of a Polyolefin or a polyamide is / are made. Multilayer composite pipe according to one of the preceding claims, wherein at the end piece ( 6 ), preferably at the outer portion ( 8th ), a circumferential seal ( 9 ) is attached. Multilayer composite pipe according to one of the preceding claims, wherein the seal ( 9 ) is formed of a thermoplastic elastomer. Multilayer composite pipe according to one of the preceding claims, wherein the seal ( 9 ) on the tail ( 6 ), preferably in the 2K process, is injection-molded. Multilayer composite pipe according to one of the preceding claims, wherein between the intermediate layer ( 3 ) and the external ( 5 ) and / or the inner layer ( 1 ) a bonding agent layer produced from a further polymer ( 2 . 4 ) is provided. Method for producing a multilayer composite pipe, comprising the following steps: a) providing a multilayer composite pipe with an inner layer ( 1 ), an outer layer made from a second polymer ( 5 ) and one between the inner ( 1 ) and the outer layer ( 5 ) embedded, made of metal intermediate layer ( 3 b) inserting the one end (E) of the multilayer composite pipe into an injection mold and closing a passage of the multilayer composite pipe with a core and c) overmoulding at least the end edges (S1, S3) of the inner ( 1 ) and the outer layer ( 5 ) by injection molding with a third polymer, so that a circumferential, the inner ( 1 ) and the outer layer ( 5 ) connecting and preventing ingress of liquid between them ( 6 ) forms. The method of claim 13, wherein the molded end piece ( 6 ) a the inner wall in sections overlapping circumferential inner section ( 7 ) having. The method of claim 13 or 14, wherein before step lit. b) an inner diameter (D _i ) at the end (E) is widened. A method according to any one of claims 13 to 15, wherein an expansion amount of the expansion is about twice a thickness (D) of the inner portion (FIG. 7 ) corresponds. A method according to any one of claims 13 to 16, wherein an axial length of the expansion is greater or approximately equal to an axial length of the inner portion ( 7 ). Method according to one of claims 13 to 17, wherein the end piece ( 6 ) a peripheral outer portion overlying the outer wall ( 8th ) having. Method according to one of claims 13 to 18, wherein an outer diameter (A ₁ ) of the outer portion (A ₁ ) 8th ) is larger than another outer diameter (A ₂ ) of the multilayer composite pipe. A method according to any one of claims 13 to 19, wherein the third Polymer and the first and / or the second polymer from the same Material are formed. A method according to any one of claims 13 to 20, wherein first and / or second and / or third polymer a polyolefin or a Polyamide is used. Method according to one of claims 13 to 21, wherein at the end piece ( 6 ), preferably at the outer portion ( 8th ), a circumferential seal ( 9 ) is attached. Method according to one of claims 13 to 22, wherein the seal ( 9 ) is made of a thermoplastic elastomer. Method according to one of claims 13 to 23, wherein the seal ( 9 ) on the tail ( 6 ), preferably in the 2K process, is injection-molded. Method according to one of claims 13 to 24, wherein the multilayer composite pipe between the intermediate layer ( 3 ) and the external ( 5 ) and / or the inner layer ( 1 ) a bonding agent layer produced from a further polymer ( 2 . 4 ) having.