DE19504609C2 - Multi-layer - multi-channel plastic pipe - Google Patents

Description

The invention relates to a plastic pipe according to the Preamble of claim 1.

Single-layer plastic pipes made of polyamide for automobile construction are state of the art and are used in a variety of ways, e.g. B. for brake, hydraulic, fuel, cooling and pneuma tikleitung (see German standard DIN 73 378 "pipes made of Po lyamide for motor vehicles "). They must be chemically, thermal, mechanical and hydraulic among those in practice exposure conditions occurring during operation be cher, e.g. B. as fuel lines.

Single-layer pipes fulfill under certain conditions of use inadequate against the intended requirements, e.g. B. in the case of fuels containing alcohols (e.g. methanol) and / or aro contain hydrocarbons (e.g. benzene).  

This can lead to swelling, reduced strength and Dimensional changes of the pipe come to a increased diffusion of the fluids conveyed through them the pipe wall and thus pollute the environment.

Increasingly stricter legal regulations force egg ner reduction of emissions and thus especially the diffusion sions.

In addition, for reasons of cost, more and more come in automotive construction Cable bundle for use, which consists of several, parallelge led, pre-assembled, individual lines that exist in one step very cost-effective during the final assembly of the Vehicle can be mounted on the assembly line. Such line Bundles are known, for example, from EU 0 235 576 B1. The individual pipes of the pipe bundle or pipe bundle summarized via connecting means. The main effort for Such bundles of lines therefore exist in the manufacture of the individual line and in its pre-assembly with the supply ranten.

There are stricter demands for active and passive Vehicle security. Significant in the event of a fire Do this to ensure as long as possible len that the fuel that is in the fuel lines is due to rapid melting and / or Burning her wall does not ignite.  

An attempt was made to address the disadvantages of single-layer plastic pipes through multilayer pipes for an improvement of the Diffusion behavior (DE 35 10 395, DE 37 15 251, DE 38 21 723, DE 39 38 497, DE 40 01 125), the flame retardant (DE 38 17 841, DE 24 53 238, DE 21 40 806, DE 20 25 351) or by Multi-channel (DE 26 00 859, DE 26 44 349, DE 26 60 524, DE 28 14 595, DE-GM 96 31 085, EP 0 318 434, EP 0 596 507) to decrease.

In some cases, individual successes for the diffusion method hold (DE 43 09 829, DE 43 10 884) and the flame retardant (DE 38 40 750) can be achieved, a practical and closed its solution to the triple task of reducing diffusion, Flame retardancy improvement and multi-channeling has so far stood completely out.

The object of the invention is therefore to provide a multi-layer, multi-channel plastic tube create whose properties, e.g. B. as a plastic pipe system in the installed state in Motor vehicles are: low diffusion, adequate fire protection, parallel transport of Fluids, good dimensional stability, good mechanical and technical resilience, good chemical Properties, good temperature change behavior, low manufacturing price. The solution to this Task leads to a multi-layer pipe according to the characteristic features of claim 1.

In particular, the geometric arrangement of the individual parallel channels, preferred wise circular, there is considerable additional importance for both Functionality as well as the manufacturing price. The axes of these channels can be on one any geometric line, but preferably a straight line or more than two Channels, be arranged on a pitch circle. The connection of two neighboring canal banks dung can be done directly or, a little further apart, through an intermediate bridge. This The intermediate bridge can be arranged internally, centrally or externally on a pitch circle to be appropriate. In all practical applications, this is different stretch behavior of plastics and i. a. to take account of metallic pipe connections, this leads to leaks in the pipeline system in temperature cycling at the limit - 40 ° C can lead to + 120 ° C in the car.

The structure of the pipe is based on the geometrical arrangement and the manufacturing possibility. Here, the body of the multi-channel pipe is decisive in terms of strength. Thereon build the diffusion-inhibiting layer from the inside out, as well as on the very outside, the flame retardant layer.  

The formation of at least one foam layer, preferably with the molding compound polyamide (PA), preferably cross-linked, in the outer envelope area of all channels with at least a foam-forming additive, the reaction temperature of which is higher than the processing temperature, considerably improves the flame protection of the entire pipe. The foaming layer leads on the one hand to a high thermal insulation of the internal layers containing flammable fluids, with the result that the high temperature only after a comparatively long exposure time, the inner layer is seriously impaired. On the other hand, foaming means that the inner layer is effective for a particularly long time is protected against the entry of oxygen.

In the event of fire, the foam layer needs a mechanical outside Reinforcement or an additional fire-retardant improvement. This improvement through the outer layer is brought about by preferably crosslinking the molding compound Polyamides, with additional fire-retardant additives.

The mechanical bond between the load-bearing inner layer, which is preferably made of polyamide is formed and the body of the tube, and the diffusion layer must through a special thin adhesive layer can be ensured. By traction in the border surfaces of these neighboring layers (inner to diffusion layer) prevent them Separation and it is responsible for the mechanical stability (e.g. with vibrations or Vibrations). The selection of the molding compound used or the molding compound mixture accordingly, this functional layer is of considerable functional importance. According to the invention it can consist of polymeric polyamide plus copolymers Polyacrylic acid esters or from polymeric polyvinylidene fluoride (PVDF) plus copolymers Polymethyl methacrylates.  

The multilayer pipes are preferably produced in a known manner inexpensive on coextrusion lines. The networking of the individual molding compounds can done chemically or by blasting. Further features of the invention result from the Claims.

The drawing shows in detail, by way of example, m channels with preferably the same Circular cross section and n layers:

Fig. 1 shows a cross section through a 4-channel 5-layer pipe in the arrangement of a partial straight line for the channels (m = 4, n = 5).

Fig. 2 shows a cross section through a 4-channel 5-layer pipe in the arrangement of a partial straight line for the channels and each with 2 webs (m = 4, n = 5).

Fig. 3 shows a cross section through a 4-channel 5-layer pipe in the arrangement of a pitch circle for the channels (m = 4, n = 5).

Fig. 4 shows a cross section through a 4-channel 5-layer pipe in the arrangement of a pitch circle for the channels and each with 2 webs (m = 4, n = 5).

Fig. 5 shows a cross section through a 5-channel 5-layer pipe in the arrangement of a pitch circle for 4 channels and a central channel and each a web (m = 5, n = 5).

Fig. 6 shows a cross section through a 4-channel 5-layer pipe in the arrangement of a pitch circle for the channels and an outer web on the enveloping circle of the channels (m = 4, n = 5).

FIG. 7 shows a cross section through a section of the tube according to FIG. 6 under the action of a flame (m = 4, n = 5).

Fig. 8 shows a cross section through a 4-channel 5-layer pipe in the arrangement of a pitch circle for the channels and an inner web (m = 4, n = 5).

Fig. 9 shows a cross section through a 3-channel 5-layer tube in the arrangement of a pitch circle for the sector-shaped channels (m = 3, n = 5).

Fig. 10 shows a cross section through a 4 channel 5 layer pipe in the arrangement of a pitch circle for the segment-shaped channels, and a central axis for the central, circular channel (m = 4, n = 5).

In Fig. 1 is a tube (15) with four channels (13), which preferably have an identical circular cross-section and the channel axes (12) are arranged on a pitch line (17) represented. The individual adjacent channels ( 13 ) touch each other directly in the contact zone ( 18 ). A closed geometric curve in the form of an enveloping circle ( 10 ) fictionally encloses the tube ( 15 ). An ellipse can also be used as the envelope, the large axis of which corresponds to the outer width of the tube ( 15 ). The layer structure is the following from the inside to the outside: the inner layer ( 1 ) represents the supporting body of the entire tube ( 15 ) and its channels ( 13 ). The entire outer covering of this body ( 1 ) is covered by the adhesive layer ( 2 ), the diffusion layer ( 3 ), the foam layer ( 4 ) and the outer layer ( 5 ) are formed.

In FIG. 2 is a tube (15) with four channels (13), which preferably have an identical circular cross-section and the channel axes (12) are arranged on a pitch line (17) represented. The individual adjacent channels ( 13 ) are each connected to one another by two tube webs ( 6 ); this leads to hollow channels ( 19 ) which are without a direct function. A closed geometric curve in the form of a wrapping circle ( 10 ) fictitiously surrounds the tube ( 15 ); this curve could also be an ellipse, the major axis of which corresponds to the outer width of the tube ( 15 ). The further layer structure is analogous to FIG. 1: inner layer ( 1 ), adhesive layer ( 2 ), diffusion layer ( 3 ), foam layer ( 4 ), outer layer ( 5 ).

In Fig. 3 is a tube (15) with the pipe axis (11) and four channels (13), which preferably have an identical circular cross-section and the channel axes (12) are arranged on a pitch circle (9), is shown. A channel ( 13 ) is affected by two adjacent channels ( 13 ) each in a contact zone ( 18 ); this leads to a hollow channel ( 19 ) which has no function. A closed geometric curve in the form of an enveloping circle ( 10 ) fictionally encloses the tube ( 15 ). The further layer structure is analogous to FIG. 1 inner layer / body ( 1 ), adhesive layer ( 2 ), diffusion layer ( 3 ), foam layer ( 4 ), outer layer ( 5 ).

In FIG. 4 is a tube (15) with four channels (13), which preferably have an identical circular cross-section and the channel axes (12) are arranged on a pitch circle (9), is shown. A channel ( 13 ) is connected by two adjacent channels ( 13 ) each with an inner web ( 16 ) and an outer web ( 14 ). This leads to four hollow channels ( 19 ) each between the inner ( 16 ) and outer web ( 14 ) and a central hollow channel ( 19 ), the axis of which is identical to the tube axis ( 11 ); these hollow channels ( 19 ) have no function. A closed geometric curve in the form of an enveloping circle ( 10 ) fictionally encloses the tube ( 15 ). The further layer structure is analogous to FIG. 1: inner layer / body ( 1 ), adhesive layer ( 2 ), diffusion layer ( 3 ), foam layer ( 4 ), outer layer ( 5 ).

In FIG. 5, a tube (15) with five channels (13), which preferably have an identical circular cross-section and its four-channel axes are arranged (12) on a pitch circle (9), or the axis of the inner channel (20) is identical with the tube axis ( 11 ) is shown. One of the four channels ( 13 ), the channel axes ( 12 ) of which are on the pitch circle ( 9 ), each has two analog channels ( 13 ), each with an outer web ( 14 ) and inside with a wall section ( 21 ) of the inner channel ( 20 ) as a contact zone, interconnected; this leads to four hollow channels ( 19 ) which have no direct function. A closed geometric curve in the form of an enveloping circle ( 10 ) fictionally encloses the tube ( 15 ). The further layer structure is analogous to FIG. 1: inner layer / body ( 1 ), adhesive layer ( 2 ), diffusion layer ( 3 ), foam layer ( 4 ), outer layer ( 5 ).

In FIG. 6 is a tube (15) with four channels (13) preferably formed by four tube webs (6) in the present case as outer webs (14) are connected together. These tube webs ( 6 ) have the function of ensuring the unrestricted expansion behavior of the individual channels ( 13 ) when they are installed as pipelines in a motor vehicle in the event of temperature changes from -40 ° C. to + 120 ° C. These requirements of the webs ( 6 ) and channels ( 13 ) to each other ensure the tightness of the channels ( 13 ) in connection with the usually metallic channel connections in ready-to-use lines, the thermal expansion behavior of which differs significantly from that of the plastics and must therefore be taken into account geometrically. The elastic expansion behavior of the plastics would not be sufficient due to plastic deformation.

The enveloping circle ( 10 ) defines the outer diameter of the tube ( 15 ) by touching the outer surface lines of the four tube channels ( 13 ) and the four outer webs ( 14 ); the central tube axis ( 11 ) represents the center point of the enveloping circle ( 10 ) in the case of a vertical section plane through its axis ( 11 ). The channel axes ( 12 ), based on the same section plane, lie on the pitch circle ( 9 ), the center point of which is the pipe axis ( 11 ) is.

The tube ( 15 ) is constructed in different layers from the inside to the outside as follows: the inner layer ( 1 ) represents the body of the tube with its four channels ( 13 ); this layer determines the structural strength of the pipe. This inner layer ( 1 ) is enveloped by an adhesive layer ( 2 ), which produces the force-locking mechanical bond between the inner layer ( 1 ) and the diffusion-inhibiting diffusion layer ( 3 ); this adhesive layer ( 2 ) is matched to the molding compositions of the two adjacent layers ( 1 ) and ( 2 ). The outer flame protection of the tube ( 15 ) is brought about by the two further layers which form the outer structure of the channels ( 13 ) and the outer webs ( 14 ) on the encapsulation circle ( 10 ); these are the foam layer ( 4 ) and the outer layer ( 5 ). The foam layer ( 4 ) contains at least one foaming additive, the reaction temperature of which is higher than the processing temperature of the tube during extrusion; the outer layer ( 5 ) has at least one flame-retardant additive. The preferably crosslinking of layers ( 3 ), ( 4 ) and ( 5 ) achieves additional stability, which has an advantageous effect in the event of external flame or heat.

In Fig. 7, the external punctual flame action ( 7 ) on the pipe ( 15 ) or in relation to a channel ( 13 ) is shown. As soon as the reaction temperature is higher than the processing temperature, foaming ( 8 ) of the foam layer ( 4 ) takes place and good thermal insulation is formed from the fluid in the channel ( 13 ), e.g. B. Fuel. At the same time, at least one additive in the outer layer ( 5 ) inhibits the fire of this layer, which is set to be self-extinguishing accordingly. An additional crosslinking, be it chemical or by blasting, with the foam layer ( 4 ) and the outer layer ( 5 ) considerably increases the flame retardant effect.

In FIG. 8, a pipe is illustrated (15) with four channels (13) which is formed by four tubular bars (6) in the present case as the inner webs (16) are connected. The function of these webs ( 6 ) is the same as described under Fig. 1. The enveloping circle ( 10 ) affects the outer surface lines of the four channels ( 13 ). The arrangement of the tube axis (11) and the four channel axes (12), and the design and function of the layers (1), (2), (3), (4), (5) is analogous to FIG. 1 to FIG. 6 Due to the geometric design of the tube ( 15 ), the layers ( 2 ) to ( 5 ) largely envelop the entire channels ( 13 ) and the outer contour of the inner webs ( 16 ); the surface of the entire pipe is accordingly larger.

In FIG. 9, a circular tube (15) is represented by m = 3 sector-shaped channels (13) of equal cross section, the channel axes (12) lie on a pitch circle (9). The wall sections ( 21 ) of two adjacent channels ( 13 ) are tube webs ( 6 ) directed radially outwards. The inner layer ( 1 ) forms the supporting body of the entire tube ( 15 ); their outer geometric shape is preferably circular. The adhesive layer ( 2 ), the diffusion layer ( 3 ), the foam layer ( 4 ) and the outer layer ( 5 ) are arranged radially outwards. The outer enveloping circle ( 10 ) is identical to the outer diameter Da of the tube ( 15 ) with the tube axis ( 11 ).

In FIG. 10, a circular tube (15) is represented by m = 4 channels (13) with same cross section, with three channels (13) segment-shaped and an inner channel (20) are circular. The axis of the inner channel ( 20 ) is also the tube axis ( 11 ); the channel axes ( 12 ) of the segment-shaped channels ( 13 ) lie on a pitch circle ( 9 ). The contact zones ( 18 ), which are at the same time wall sections ( 21 ), of two adjacent segment-shaped channels ( 13 ) are radially outwardly directed tube webs ( 6 ); the wall sections ( 21 ) of the inner channel ( 20 ) to the segment-shaped channels ( 13 ) are identical to the wall thereof. The inner layer ( 1 ) simultaneously forms the supporting body of the entire tube ( 15 ); their outer geometric shape is circular. The adhesive layer ( 2 ), the diffusion layer ( 3 ), the foam layer ( 4 ) and the outer layer ( 5 ) are arranged radially outwards. The outer enveloping circle ( 10 ) is identical to the outer diameter Da of the tube ( 15 ).

Derived from FIGS . 6 and 8 with the extreme layers of the tube webs ( 6 ) as outer ( 14 ) or inner webs ( 16 ) numerous other layers of such webs ( 6 ), z. B. in intermediate layers, conceivable; it is also analogous for the number in the channels ( 13 ) to implement further designs m </ = 3 with 1 = / <n = / <6 layers. Certain layers can also be summarized in their function, e.g. B. the diffusion layer ( 3 ) with the molding compound C and the foam layer ( 4 ) with the molding compound D in a new layer ( 3/4 ) with the new molding compound F.

Reference list

1. Inner layer (body)
2. Adhesive layer
3. Diffusion layer
4. Foam layer
5. outer layer
6. Pipe bridge
7. Flame exposure
8. Foaming
9th pitch circle
10. Wrapping circle
11. Pipe axis
12. Channel axis
13th channel
14. Outer dock
15. Pipe
16. Inner bridge
17th division line
18. Touch zone
19. Hollow channel
20. Inner channel
21. Wall section
m number of channels
n number of layers
Since diameter (a = outside, i = inside)
S1 layer thickness (layer 1 ; 2 , 3 , 4 , 5 )
S wall thickness tube

Claims (34)

1.Multi-layer, multi-channel plastic pipe, consisting of m internal channels and n layers (m <1, n <1; each integer), dimensionally determined by its main dimensions (inside channel diameter, outside tube diameter, number of channels, number of layers, channel wall thicknesses, web thicknesses, channel division), produced by the coextrusion process, used in the automotive sector for brake, compressed air, hydraulic, fuel and cooling lines, the wall of which is at least one load-bearing, diffusion-reducing, non-positive, foamable and flame-retardant Layer or at least a combination of at least two relevant layer features, characterized in that the tube ( 15 ) and / or its elements is constructed as follows:

• - materially from the inside out,
  the inner layer ( 1 ) made of a molding compound A of a thermoplastic polymer,
  the adhesive layer ( 2 ) made of a molding material mixture B with a minimum 50% by weight of a thermoplastic polymer and a maximum of 50% by weight of thermoplastic copolymers,
  the diffusion layer ( 3 ) made of a molding compound C of a thermoplastic polymer,
  the foam layer ( 4 ) made of a molding compound D of a thermoplastic polymer which contains at least one blowing agent-containing additive, the reaction temperature of which is higher than the processing temperature,
  the outer layer ( 5 ) made of a molding compound E of a thermoplastic polymer which contains at least one flame-retardant additive;
• - geometric,
  the pitch on which the axes ( 12 ) of the channels ( 13 ) are arranged, is located on at least one geometrically defined dividing line, the pipe envelope represents a geometrically defined curve and the areas of the cross sections of the m channels ( 13 ) are identical.

2. Multi-layer, multi-channel plastic pipe, according to claim 1, characterized in that the geometric division line is a division line ( 17 ). 3. Multi-layer, multi-channel plastic tube, according to claim 1, characterized in that the geometric dividing line is closed and forms a pitch circle ( 9 ). 4. Multi-layer, multi-channel plastic pipe, according to claim 1 to 3, characterized in that the walls of adjacent channels ( 13 ) touch in a contact zone ( 18 ). 5. Multi-layer, multi-channel plastic pipe, according to claim 1 to 3, characterized in that the walls of adjacent channels ( 13 ) are connected by at least one tube web ( 6 ). 6. Multi-layer, multi-channel plastic tube, according to claim 1 to 5, characterized in that the tube web ( 6 ) is designed as an inner web ( 16 ). 7. Multi-layer, multi-channel plastic pipe according to claim 1 to 5, characterized in that the tube web ( 6 ) is designed as an outer web ( 14 ) and in its outer contour affects the enveloping circle ( 10 ) of the tube ( 15 ). 8. Multi-layer, multi-channel plastic tube according to claim 1 to 7, characterized in that the tube web ( 14 ) is all outer web ( 14 ) plus inner web ( 16 ). 9. Multi-layer, multi-channel plastic pipe according to claim 1 to 8, characterized in that the inner layer ( 1 ) has a layer thickness of at least 0.5 mm. 10. Multi-layer multi-channel plastic pipe according to claim 1 to 9, characterized in that the adhesive layer ( 2 ) has a layer thickness of less than 0.1 mm. 11. Multi-layer, multi-channel plastic pipe according to claim 1 to 10, characterized in that the diffusion layer ( 3 ) has a layer thickness of at least 0.1 mm. 12. Multi-layer, multi-channel plastic pipe according to claim 1 to 11, characterized in that the foam layer ( 4 ) has a layer thickness of at least 0.3 mm. 13. Multi-layer multi-channel plastic pipe according to claim 1 to 12, characterized in that the outer layer ( 5 ) has a layer thickness of at least 0.2 mm. 14. Multi-layer multi-channel plastic pipe according to claim 1 to 13, characterized in that the main dimensions of the channels ( 13 ) with outer web ( 14 ) for the inner layer inner diameter, the inner layer outer diameter, layer thicknesses and their tolerances of the German standard DIN 73 378 for the through range of 4 mm and the wall thickness range of 0.75 mm or 6 mm correspond to 0.5 mm. 15. Multi-layer multi-channel plastic pipe according to claim 1 to 13, characterized in that the main dimensions of the channels ( 13 ) with inner web ( 16 ) for the inner channel diameter, the channel outer diameter, channel thickness and their tolerances of the German standard DIN 73 378 for the outer diameter range 6 mm and the wall thickness range 1.5 mm. 16. Multi-layer multi-channel plastic pipe according to claim 1 to 15, characterized in that the molding compound A of the inner layer ( 1 ) consists of polyamide. 17. Multi-layer, multi-channel plastic tube according to claim 1 to 16, characterized in that the molding compound mixture B of the adhesive layer ( 2 ) consists of polymeric polyvinylidene fluoride and copolymeric polymethyl methacrylates. 18. Multi-layer multi-channel plastic pipe according to claim 1 to 17, characterized in that the molding compound mixture B of the channel adhesive layer ( 2 ) consists of polymeric polyamide and copolymeric polyacrylic acid esters and their derivatives. 19. Multi-layer, multi-channel plastic pipe according to claim 1 to 18, characterized in that the molding compound C of the diffusion layer ( 3 ) consists of polyvinylidene fluoride. 20. Multi-layer, multi-channel plastic pipe according to claim 1 to 19, characterized in that the molding compound D of the foam layer ( 4 ) consists of polyamide. 21. Multi-layer, multi-channel plastic pipe according to claim 1 to 20, characterized in that the molding compound E of the outer layer ( 5 ) consists of polyamide. 22. Multi-layer, multi-channel plastic pipe according to claim 1 to 21, characterized in that the chemical molding compound E of the outer layer ( 5 ) has a physical mass fraction of max. Contains 15% conductive carbon black. 23. Multi-layer, multi-channel plastic tube according to claim 1 to 22, characterized in that the molding compound mixture C is cross-linked with the diffusion layer ( 3 ). 24. Multi-layer, multi-channel plastic tube according to claim 1 to 23, characterized in that the molding compound mixture A is cross-linked with the inner layer ( 1 ). 25. Multi-layer, multi-channel plastic pipe according to claim 1 to 5, 7 to 24, characterized in that the outer web ( 14 ) is part of the adhesive layer ( 3 ), the diffusion layer ( 3 ), the foam layer ( 4 ) and the outer layer ( 5 ) is. 26. Multi-layer, multi-channel plastic pipe according to claim 1 to 5, 7 to 25, characterized in that the inner web ( 16 ) consists of the 5 layers ( 1 ), ( 2 ), ( 3 ), ( 4 ) and ( 5 ) . 27. Multi-layer, multi-channel plastic pipe according to claim 1 to 26, characterized in that the surfaces of the channels ( 13 ) form a circular cross section. 28. Multi-layer, multi-channel plastic tube, according to claim 1, 3 to 13 and 16 to 26, characterized in that the surfaces of the channels ( 13 ) form a sector-shaped cross section. 29. Multi-layer, multi-channel plastic pipe, according to claim 1, 3 to 13 and 16 to 26, characterized in that the surfaces of the channels ( 13 ) each form several segment-shaped and a circular cross-section. 30. Multi-layer, multi-channel plastic pipe according to claim 1 to 29, characterized in that the chemical molding compound A of the inner layer ( 1 ) has a physical mass fraction of max. Contains 15% conductive carbon black. 31. Multi-layer, multi-channel plastic tube according to claim 1, characterized in that the channels ( 13 ) have a circular cross-section. 32. Multi-layer, multi-channel plastic pipe according to claim 1, characterized, that the molding compound D of the thermoplastic polymer ver is networked. 33. Multi-layer, multi-channel plastic pipe according to claim 32, characterized, that the molding compound E of the thermoplastic polymer ver is networked. 34. Multi-layer, multi-channel plastic pipe according to claim 1, characterized in that the pipe envelope is a wrapping circle ( 10 ).