Method of producing a composite part and use the same.

[0001] The invention relates to a method of producing a composite part, comprising at least one inner hollow moulded body with openings, which openings are accessible during the composite part. Also the invention relates to a use of a composite part produced by the process.

[0002] For connecting of thermally insulated pipes, as they are used for example to transport media such as water cooled, sleeves are used. This sleeves consist of an inner part, through which the medium flows, usually a hollow body of polyethylene (PE). This hollow body is, except at its openings for the medium, the outside completely surrounded by a thermally insulating material, usually polyurethane (PU). This sleeves are thus thermally insulated so as to avoid that the ambient air the cooled medium heated. On the surface of the sleeve must be no condensed water and the surface must also be mechanically resistant form, so as to cope with the stresses of the mounting is located comes, therefore often a sheath of PE for use, which is on the thermal insulation. The sleeves can have various forms. So exist straight connector, but also curved shapes or T-pieces are required. In many cases these sleeves also feature additional channels on, the lead must remain open at the top and outwardly. This channels serve as contact points for cables, which during assembly are connected with the tube ends sleeve endselectrical welding the inhibit.

[0003] The making such composite parts are can be carried out, by the inner part in the PE-jacket-foamed with a suitable material is introduced and after central centering. This is problematic that can be bent or branched so not processed interior pieces can take place, because the positioning within the prefabricated PE-jacket not. Therefore this method is only for straight pieces can be used universally, which have no contact points for electrical welding. Another disadvantage is the need for, the PE-jacket must be made available. This parts must be injection molded expensive. Furthermore, the wall thickness is of the PE-jacket is relatively large, which means a high material costs.

[0004] In DE 10,153,855 A1 is described a method, in which a shaped part is injected behind only partially at a defined location with a foam, after the surface of the mold with a decorative coating material which has been provided at this point, the forms the surface of the finished component later. This function of this surface is primarily decoratively, special mechanical resistance is not mentioned. The foam used has no thermally insulating function.

[0005] Instead of a varnish is sprayed in the mold, can also be inserted a molded skin, which then forms the surface of the finished composite part. These is described in DE 10 2007,061,643 A1 for example. A disadvantage of this method is the production of the molded skin in a separate working step the need. Furthermore, a one-component PU is used-system, which needs to be tempered, to harden.

[0006] The 1,190,828 A1 describes a similar procedure but with the difference EP that the mold is composed of several parts, what the Demoulding of more complex composite parts with undercuts simplified.

[0007] US 5,223,193 A is a method claimed in the, wherein on the surface of the mold a reactive isocyanate/polyol mixture is applied. Further rotating the mold for enabling uniform distribution on the surface to effect foaming takes place and then start with a second PU-system. In this method no internal part is encapsulated.

[0008] US 5,580,501 A described in the is, as a first layer into a mold in the form of a PU-based powder coating is applied. Also in the method, a temperature control is needed to bring the powder coating to melt and for the reaction. Innnenliegende parts, which are encapsulated, are not provided.

[0009] US 2005,244,628 A is described in the, such as a soft article can be made, first of all into a mold and then applied by a coating is also a second coating with another polymer. A rigid foam will take place here no use.

[0010] The task of the invention is to create an efficient method of manufacturing composite parts are, consisting of a prefabricated plastic molding, through which a temperature-controlled liquid medium is guided in the finished composite part, a thermal insulation layer having thereon a surrounding this molded article against mechanical stress resistant surface layer. This surface layer is to a closed, a high-quality impression surface resulting form of the composite part.

[0011] The formulated task is solved by the features of claim 1.

[0012] The advantages of the claimed method are diverse. A complex composite part is made of plastic in a few processing steps, which not only difficult, or even could be made with alternative methods. The few method steps is a high throughput and a good By ensure productivity. Furthermore, the production step is omitted for the PE-outer jacket, the no longer is needed. These also has a considerable material savings result because the cladding layer is applied in each case only in thickness, which is actually needed for the end-use application. 0.1 mm to 3 mm is substantially less than the thickness of The preferred thickness of the normally used PE-outer casing, which is from 3 mm to 6 mm. The characteristics of the surface of the composite part by the choice of the material of the cladding layer can be determined in the tool applied, as is the connection between the cladding layer and the thermally insulating foam. By the gradual process flow can thus be adapted specifically to suit the individual case the final characteristics of the composite. For example, the surface with respect to the hardness by the selection of the cladding layer are changed. Therefore a very specific function takes over each part of the composite, the inner part serves the transport of the temperature-controlled medium, the insulating foam has good properties with respect to the heat insulation and is relatively hard so as to provide a good overall stability, the outer skin and is insensitive to scratches or other elastic behaviour shows a mechanical influences.

[0013] How is mentioned the cladding layer preferably having a thickness in the range of 0.1 mm to 3 mm applied. The thickness can be selected depending on the use of the composite part, so that this satisfies the requirements at the particular use. The thickness can be chosen in particular from 3 mm to lie. In particular, the cladding layer is applied by spraying a plastic material in the mould parts, which allows a rapid and targeted application in the desired thickness. The cladding layer is polyurethane-based formed Preferably,. This produces the desired connection between the cladding layer and of the thermal insulation, which preferably is a PU-foam. The cladding layer can be single-layer or multi-layer applied in the tool when applied.

[0014] The addition of the at least one prior to closing the mold in the forming tool preferably mousse component, so that e.g. two components to form the PU foam into the open lower tool part are cast has been positioned, after the shaped article in the tool part. Afterwards the upper tool part are fixed is placed and the tool parts. It the formation of foam and the connection of the foam takes place with the cladding layer and the die body. Alternatively, the tool takes place via the introduction of the foam-forming substances and it is first closed to at least one opening provided in the tool.

[0015] at least one cladding layer is preferably formed in such a way, the plastic material for the cladding layer is selected or has so that the cladding layer as a surface of the composite part a hardness of at least 40 Shore-D. It is further possible to apply a plurality of cladding layers apply a further cladding layer or at most the demolded composite part, if this is desired in order to achieve special surface properties of the composite part. Thermally insulating plastic foam has a thermal conductivity preferably smaller 0,040 W/m * K The measured at 50 °C according to the standard, and in particular a compressive strength of at least 100 kPa EN12 667 on, as determined in accordance with standard ISO 844.

[0016] an isocyanate/polyol mixture Preferably, the thermally insulating plastic foam formed from, which is formed of chemically reacting at room temperature. The opening and the removal of the composite body of the tool parts Preferably, , if the cure is advanced sufficiently, among which in particular is understood that a conversion of the components of the the thermally insulative plastic foam is at least 80% to 95% is carried out in the mould to form. It is further preferred, if the contact surfaces of the tool parts are narrow, so that the tool parts 0.5 millimeter to 1 millimeter extends only over a width of contact. These Oualität the cladding layer in the region of the contact surfaces results in a, the a trimming after demolding can make superfluous.

[0017] The foam-encased shaped body having any shape can, also bent parts or T-pieces can be successfully processed. Also it is readily possible, to use shaped bodies, which comprise webs in any position, channels or other appendage.

[0018] The preferred use of the composite part is in accordance with the procedure as sleeve for connecting a thermally insulated pipes have been manufactured by the use, comprising an inner tube, a surrounding thermal insulation and an outer jacket this. The use takes place in a manner known per se, in the connecting region exposed by the composite part or respectively of the sleeve into the openings of the inner tubes of the tubes suitably be inserted and fixed there.

[0019] Additional embodiments, advantages and applications of the invention emerge from the dependent claims and from the now following description with reference to the Figures. Indeed

Fig. 1 a plan view of the one tool part of the mould;

Fig. 2 is a front view upon the closed mold; and

Fig. 3 is a front view of a composite part.

[0020] The Fig. 1 to 3 an execution is described as an example of the invention. It is for simplifying the drawing the shaped body as a cylindrical shaped body without branches been selected. As mentioned, the method allows the production of composites with more complex shapes according to the invention but of the inner mould part.

[0021] 1 shows a plan view of the first tool part 7 of a two-part Fig. 6 7 8 in the closed state and are. Both tool parts forming tool in Fig. 2 can be seen. In Fig. 9 shows the plan view on the tool part 7 whose mold walls 1, in this example the shape of a round semi-cylinder has the. With the upper or second tool part 8 results in a cylindrical shape, such that the demolded composite part is externally cylindrical, as can be seen in the frontal view of the composite part 1 of 3 Fig.. 4 and 5 of the mould 1 are further closure parts Fig. In represented cut. In this example the closure parts 4 and 5 at the same time serve to position the shaped body 2,1 only with broken lines is represented in Fig.. Also the closure parts 4 and 5 also take over the function of closing the front openings Umschäumens 3 of the shaped body during the process or during the 2. Point 4 and 5 the closure parts To this end plug 4 'or 5' on, which are dimensioned so close abut that they project through the openings 3 of the shaped body and on the inner wall of the moulded body 2 into the interior of said body, so that they the openings schaumdicht 3. 2 has a more complex shape with more openings if the shaped body, separate means or this way can accordingly. Plug for closing these openings be provided. Separate means for positioning by the closure of the mould can also further 2 be provided in the mould of the molded body. Also the forming tool can be formed from more than two tool parts. 4 and 5 can on any known manner to the stopper parts The be fixed tool parts. In Fig. 1 is indicated during the closure part 5 that this with a flange 51", the engages with a corresponding groove in the tool part, can be fastened at the tool part.

[0022] 9 of the tool parts is applied prior to the location of the mold walls On 2 and 4 of the closures shaped body, 11 the cladding layer 5, wherein this takes place in particular on the whole mold walls, so that it completely by the outer layer 11 is covered. The cladding layer 2 and 3 is to improve the way in which in part with a thicker line Fig. graphically highlighted Fig., wherein the cladding layer 11 behind the closure part 2 in the inner of the forming tool 5 in Fig. and actually is not visible. The cladding layer is preferably applied by spraying on the inner wall 7 and 9 each tool part 8. Continue the cladding layer is a PU preferably--based plastic. The thickness of the applied cladding layer depends upon the use of the finished composite part and the properties of the plastic used to form the cladding layer. 0.1 mm to a thickness of 3 mm is preferred. The applied layer should be compatible with the subsequently used foam chemically as far as possible. The reason for this is that it comes to a good adhesion between the two components. Since preferably for the thermally insulating plastic foam is a PU-based hard foam material is applied is also advantageous for the cladding layer, a PU-system. For the use of the finished composite part is a decisive criterion the mechanical loading capacity of the surface. The hardness of the cladding layer must have a minimum value, which preferably at 40 Shore-D. The stability against other environmental influences such as chemicals or UV radiation can also be adapted.

[0023] after the application to the mold walls can 9 for a cladding layer The predetermined time or it can be flashed off wait for a reaction time for the cladding layer. Before the application of the cladding layer 11 on the mold walls 9 are applied to the mold walls 9 can, if necessary, a release layer, which facilitates the subsequent demolding.

[0024] the application of the cladding layer to the mold walls 9 of the tool parts 7 After, 8 7 the moldings is positioned in the tool part 2. 4 and 5 on the explained manner with the closing parts this can take place or by other means. Other means for positioning used Will, so the closing takes place also the openings with other means, in particular separate plug. The shaped body is preferably centrally positioned in the die 2 6, so that the thickness of the insulating foam layer in the finished composite part is uniformly. The foam forming material is introduced into the mold tool the patterns are projected. Open mold by casting into the lower mold part This can be implemented, whereupon the upper die part and the mold parts are fixed is placed, so as to form a sealed mold during the foaming and curing.

[0025] Preferably, the forming tool so designed that the respective contact surface 7 'and 8' of the two tool parts 7 and 8 each have a width in the range of 0.5 millimeter to 1 millimeter B, 7 1 for the contact surfaces as required by Fig.' is indicated, so that the two tool parts only along a correspondingly narrow contact surface contact. It has shown itself that this configuration advantageously for the nature of the surface of the composite body in the area of the touching is or that it practically no burr on the composite tool parts is produced at the location, at which the tool parts abut one another.

[0026] The foaming material, which forms the thermal insulating plastic foam is preferably a two component system, consisting of an isocyanate component and a polyol component, which reacts immediately after being poured into the mold and forms a foam, the then said inboard shaped body encloses, apart from the openings thereof, the freely be held. This the foam has sufficient insulating properties, it is preferably closed-cell and has a thermal conductivity smaller 0,040 W/m * K, measured at 50 °C EN12 667 and according to the.

[0027] The plastic foam the foaming and more preferably also connects with the shaped body with the cladding layer. As previously explained to be used for the cladding layer and the thermally insulating foam and compatible substances it preferably is a PU-based cladding layer and by a PU rigid foam. After sufficient curing of the foam layer and the finished composite part demoulded Opening the forming tool. Under sufficient curing is understood in particular that a conversion of the components of the thermally insulating plastic foam is at least 80% to 95% is carried out in the mould to form.

[0028] It may take place either a mechanical post-processing, e.g. a trimming. It is further possible to apply a further layer on the cladding layer, so as to change the surface of the composite part further.

[0029] The foam-encased shaped body can have any form, also bent parts or T-pieces can be successfully processed. Also it is readily possible, to use shaped bodies, which comprise webs in any position, channels or other appendage.

[0030] 3 shows a front view of a composite part produced with the process is converted Fig. inner mould part 3 or 2 with the opening in the longitudinal axis of the cylindrical shaped body in this example with the 2 openings lying from the thermally insulating plastic foam 12 3 2 is surrounded. This molded article. Aussen 11 lies on the foam body said cladding layer, which imparts the desired surface properties of the surface of the composite part 1. The thus obtained composite part 1 is a sleeve or similar element Prefers, which is provided for the connection of heat insulated pipes. Such pipes comprise an inner tube on, which leads the cooled or heated medium, a thermal insulation around the inner tube, in particular a PU- expanded polystyrene isolation, and an outer jacket. When using the composite part 1 for connection of such pipes in their joining region thereof is by removal of the outer casing and of the thermal insulation and the exposed inner pipe is inserted into the inner tube 1 or in the sleeve and there in a known manner the composite includes fastened in a fluid-tight manner.

[0031] in the present application are described preferred constructions of the invention during is clear to point out that the invention is not limited to, and in some other way can be performed within the perimeter of the following claims also.