DE102011006034A1 - Method for producing a composite component - Google Patents

Abstract

The invention relates to a method for producing a composite component (2, 2.1, 2.2) with an injection molding tool, comprising providing at least one molding (4, 4.1) and back-molding the molding (4, 4.1) with a first plastic melt (6) through at least one Injection device (18). The method is characterized in that the molded part (4, 4.1) is back-injected with the first plastic melt (6) through the injection device (20) through at least one recess (8) provided in the molded part (4, 4.1).

Description

The invention relates to a method for producing a composite component with an injection mold, comprising providing at least one molded part, and injection molding of the molded part with a first plastic melt by at least one injection device. In addition, the invention relates to a composite component produced by this method and an injection mold for carrying out this method.

At the present time are in various areas of technology, such. As in buildings, screens or in vehicles, increasingly plastic products, such as plastic discs used. For example, in vehicle construction it is a continuous concern to reduce the weight of a vehicle, such as a motor vehicle, rail vehicle or aircraft. One way to reduce weight is to replace the glass panes of a vehicle with lighter plastic discs.

Plastic disks may be composite components which have at least two components. A first component may be a molded part, such as a transparent molded part. The second component can be formed by injection molding the molding with a plastic melt. This composite component can be made transparent or translucent depending on the intended use later.

From the prior art, such as the DE 201 21 744 U1 or the DE 10 2005 032 664 A1 , Such composite components are known, which are produced by means of injection molding and can be used as a disc in a vehicle.

In order to produce a composite component, it is also known to introduce a molded part in a suitable injection mold and then inject this in the closed state of the injection mold with a suitable plastic melt, so that the plastic melt and the molding material cohesively connect with each other. In particular, the gap between the molding and a mold half with a plastic melt is preferably completed completely.

During the injection molding of the molded part, it must be ensured during the injection molding process that the plastic melt is clearly positioned in its position relative to the molded part. In particular, it is necessary that the Angusstechnik is formed so that the plastic melt is during the injection molding process behind the molding to avoid overspraying and wrinkling.

In a conventional injection mold a connection can be made via a cold manifold. Here, a tunnel gate with auxiliary pin, a curved tunnel gate or a film gate is used. A disadvantage of these methods, however, is that additional waste arises. Furthermore, it may be necessary for a gate to be separated. Another disadvantage of this method is that there is always a visible mark left on the composite component. This is particularly disturbing in optical components.

An alternative method according to the prior art is the so-called direct connection. For example, US Pat DE 10 2005 009 007 A1 a method for the production of composite components, in which by means of direct connection, a molded part is partially back-injected with a plastic material.

However, such a direct connection has the disadvantage that usually Angusssystem and ejector unit are on the same side of the tool. This in turn involves the requirement that long hot runner nozzles must be provided as injection devices. The associated with a long hot runner high volumes of plastic melt in the hot runner can lead to a thermal degradation of the plastic melt up to a damage of the same. Furthermore, in the case of a direct connection, a molded part can not be inserted into the mold half, which comprises the injection device. In addition, it is not possible with the direct connection to inject a plastic melt between two moldings. Finally, an optical marking is also produced in the known direct connection.

The present invention is therefore based on the object to provide a method for producing a composite component at your disposal, which allows the production of a composite component with improved optics in a simple manner.

The previously derived and indicated object is achieved according to a first aspect of the invention in a method for producing a composite component with an injection mold comprising providing at least one molded part and back molding of the molded part with a first plastic melt by at least one injection device characterized in that the molded part by at least one in the molding provided recess is back-injected with the first plastic melt.

In contrast to the prior art, it is possible according to the invention by the injection-molding of a molding with a plastic melt through a recess provided in the molding, to produce a composite component with improved optics in a simple manner. The plastic melt is thus injected by a arranged on a first side of the molding injection device through a recess in the molding on the other side of the molding.

First, a molding, such. B. a plastic molding, are provided. The molded part can be of any shape and in particular also have a complex shape.

In addition, the shaped part has at least one recess, that is to say a recess or opening. The shape and size of the recess can in principle be chosen arbitrarily, as long as it is ensured that a plastic melt can be injected through an injection device through the recess. It is understood that two or more recesses may be provided in the molded part. The number of recesses may depend on the size of the molded part and / or the number of injection devices. As injection means, a suitable nozzle, such as a hot runner nozzle, may be provided.

By means of the method according to the invention, a molded part with improved optical properties can be produced in a secure manner, ie without overspraying and / or wrinkling, with little effort. In particular, a direct connection can be made available which does not have the disadvantages of the prior art. The molding may be placed on the injector tool side of the injection mold.

In principle, as the first plastic melt any material can be used which allows a cohesive connection with the molded part. According to a first embodiment of the inventive method, at least the first plastic melt can be made of a transparent plastic material. A transparent plastic material is particularly suitable for use in plastic discs. For example, the first plastic melt may be made of polycarbonate (PC), polymethyl methacrylate (PMMA), transparent polyamide (PA), cyclo-olefin copolymer (COC). It will be understood that any other thermoplastic which is suitable for injection molding can be used for the plastic melt.

In addition, according to a further embodiment, the molded part may be made of a transparent plastic material or of a partially transparent plastic material. For example, the molding may be made of polycarbonate (PC), polymethylmethacrylate (PMMA) or a polycarbonate-polymethylmethacrylate blend. These materials are particularly suitable for use in an at least partially transparent composite component.

The molding may according to another embodiment be a film, such as a plastic film. The film may, for example, have a thickness of 0.1 to 1 mm. The film may be a single-layer or a multilayer or multilayer film. A multilayer film may be formed of the same or different materials as long as the materials are suitable for an injection molding process. In order to provide a composite component with at least one integrated function or property, in particular the molded part can be a functional film. A functional film may include, for example, heating panels, antennas, colors, logos, lights, switches and / or photovoltaic elements. In addition, the functional film can be scratch-resistant and / or suitable for infrared (IR) reflection and / or ultraviolet (UV) blocking.

In principle, the at least one recess can be provided at any position of the molded part. For example, a recess in the central region of the molding or on the edge, such as in the form of a bulge in the edge itself, be provided. Preferably, the recess can be provided according to an embodiment of the invention in an edge region of the molded part. If two of the more recesses are provided in the molded part, preferably all the recesses may be provided in the edge region. In particular, the edge region may be a region of the composite component which is not visible in the installed state. For example, the edge region in the installed state can be covered by another element or another layer. In other words, the recess is arranged in the molded part such that it is not visible in the installed state. A composite component with particularly good optical properties can be produced.

Further, the recess may have a predeterminable distance to the edge of the molding, so be completely surrounded by the molding. In this way, it may be possible to additionally use the recess as a suspension option for hooking the molded part into the injection mold.

Furthermore, in a further injection molding step, a further plastic melt can be applied to the composite component. According to a further embodiment of the method according to the invention, at least the recess in the molding after the injection molding with the first Plastic melt to be back-injected with a second plastic melt. At least the recess can be covered for visual reasons. Preferably, according to a further embodiment, the (entire) edge region of the molded part can be back-injected with the second plastic melt. The molding is back-injected from both sides.

As a second plastic melt can be used in principle any material that can connect materially connected to the molding. For example, can be used as a thermoplastic material, such as. As thermoplastic polyurethane (TPU), thermoplastic polyethylene (TPE), PC blends or PVC. The material may in particular be colored. A colored material can cover the at least one recess. The recess is therefore not visible. The second plastic melt also allows the molding of fasteners or the like.

In a further embodiment of the method according to the invention, the recess in the molded part can be shaped such that the shape of the recess corresponds to a shape of an injection core of the injection device. The injection core, that is, one end of the injection device, may have a projection. The injector core thus stands out from the rest of the tool half. Here, the injection device core or the projection of the Injektungsanrichtungskerns may have a circumferential shape that corresponds to the shape of the recess. In other words, depending on the shape of the injector core, the at least one recess may be formed. This allows the molding to be hooked onto the tool half having the injection device.

In addition, according to another embodiment, the recess in the molded part can correspond to the injection device core of the injection device in such a way that the injection device core of the injection device can be positively connected to the molded part. A positive connection is particularly preferred since no further holding devices for holding the molded part during the injection molding process are required. For example, a molded part in the form of a film can be easily hung on at least one injection device core, without the further holding device are provided. This reduces the complexity of the injection mold and can increase the production rate.

The molding may have a thickness such that the value of a projection of the injector core of the injection device is equal to the value of the thickness of the molding or greater than the value of the thickness of the molding according to another embodiment of the method of the invention. The thickness of the molded part is understood in particular to be the value which results at the edges of the at least one recess of the molded part. It is understood that this value does not have to be constant. For example, the injector core may terminate flush with the molded article. The molding and the injector core may form a unitary surface. The first plastic melt can then flow behind the molded part without any overspray or wrinkling occurring. It will be appreciated that the injector core may also protrude through the recess of the molded article, that is, the projection of the injector core is larger than the thickness of the molded article. Preferably, however, the projection of the injector core should not be formed smaller than the thickness of the molding.

In addition, for holding the molded part, a negative pressure can be generated in a tool half having the injection device. Due to the negative pressure, a molded part can be securely held in a simple manner during the injection molding process.

According to a further embodiment of the method according to the invention, at least one further molded part can be provided. The first plastic melt can be back-injected between the two mold parts through the recess provided in a molded part. The further molded part can be formed from the same material as the molded part or from another material. For example, two functional films can be provided to integrate additional functions in a composite component. The back-injection of the two molded parts by at least one recess provided in at least one molded part makes it possible to produce a composite component in a particularly simple manner.

Another aspect of the invention is a composite component made by a previously described method. As already stated, the composite component can have particularly good optical properties.

According to a further embodiment, the composite component may in particular be a plastic disk. The plastic disc can be used in particular in a vehicle.

For example, plastic windows in the window and Verscheibungsbereich, in lighting applications, in optical lenses, headlight cover, in non-transparent, for Achieving an in-depth effect flat with transparent thermoplastic as a high-gloss layer, back-splashed decorative covers, used with (backlit) panels in the car or with monitor / display covers.

Yet another aspect of the invention is an injection molding tool for performing the method described above with a first tool half and a second tool half. At least one injection device for injecting at least one molded part through at least one recess provided in the molded part is arranged in a tool half.

The injection mold, such as a 2-component injection molding machine, has two tool halves that can be moved between an open state and a closed state. When closed, the injection molding process can be performed. Hierfür at least one injection device is provided in a mold half. The injection mold, in particular the injection device, is formed such that in the closed state, a first plastic melt is injected through a recess in the molded part behind the molding. The injection molding tool can in particular have a (single) production cell. In a simple manner, a visually appealing composite component can be produced with the injection mold.

According to a first embodiment of the injection molding tool according to the invention, a shape of an injection device core of the injection device may correspond to the shape of the recess in the molded part.

According to yet another embodiment of the injection molding tool according to the invention, at least one opening for generating a negative pressure for holding the molded part can be arranged in at least one mold half. This at least one opening can be coupled to an air pressure system, so that a negative pressure can be generated in a simple manner.

Alternatively or supplementarily, at least one tool half can be made of a porous tool steel, in particular of sintered steel. About this porous tool steel, the negative pressure for fixing the molding can be transported to the surface. The advantage here is that due to the small cross-sectional area of the pores on the tool surface, there is no risk that, in the event of incorrect positioning of the molded part, melt (via the pores) can penetrate into the tool.

There are now a large number of possibilities for designing and developing the method according to the invention for producing a composite component, the composite component according to the invention and the injection molding tool according to the invention. Reference is made on the one hand to the claims subordinate to the independent claims, on the other hand to the description of exemplary embodiments in conjunction with the drawings. In the drawing shows:

1 a schematic exploded view of a first embodiment of a composite component according to the present invention;

2 a schematic exploded view of a second embodiment of a composite component according to the present invention;

3 a schematic sectional view of the second embodiment of a composite component according to the present invention;

4 a schematic partial view of an embodiment of an injection mold in the closed state according to the present invention;

5 a schematic partial view of another exemplary embodiment of an injection mold in the closed state according to the present invention;

6 a flowchart of an embodiment of a method for producing a composite component according to the present invention;

7 a schematic view of the second embodiment of a composite component according to the present invention;

8th a schematic exploded view of a third embodiment of a composite component according to the present invention;

9 a schematic sectional view of the third embodiment of a composite component according to the present invention; and

10 a schematic partial view of another exemplary embodiment of an injection molding tool according to the present invention.

Hereinafter, like reference numerals are used for like elements.

1 shows a schematic exploded view of a first embodiment of a composite component 2 according to the present invention. The composite component 2 can in particular a transparent or partially transparent plastic disc that can be used in a vehicle.

The composite component 2 includes a molding 4 and a first plastic element 6 , As will be explained in more detail below, the first plastic element 6 by an injection molding process with the first plastic element 4 materially connected.

The molding 4 and the first plastic element 6 have an octagonal shape. It is understood that the shape of the corresponding elements can be basically arbitrary and the elements may have, for example, a circular shape, triangular shape, rectangular shape, etc. It is further understood that the elements can also have an arbitrarily curved spatial form.

The molding 4 may be a foil, such as a functional foil. A functional film is z. As a plastic film in which one or more functions or properties are integrated. Examples of functions are heating fields, antennas, colors, logos, lights, switches or photovoltaics. Examples of properties are scratch resistance, IR reflectance or UV blocking capability.

Again 1 can also be seen, has the illustrated molding 4 a recess 8th on. The recess 8th is in a border area 10 of the molding 4 arranged.

Furthermore, the illustrated recess 8th formed circular. In principle, the recess 8th have any shape. As will be explained below, the shape of the recess 8th especially depending on the shape of an injector core.

2 shows a schematic exploded view of a second exemplary embodiment of a composite component 2.1 according to the present invention.

In addition to the already described molding 4 and the first plastic element 6 has the composite component 2.1 a second plastic element 12 on. The second plastic element 12 can only be in the border area 10 of the first plastic element 4 be provided. In particular, the plastic element 12 be formed of a colored material. The second plastic element 12 at least one recess 8th cover so that the recess 8th is not visible. In addition, the second plastic element 12 be shaped so that, for example, for mounting the composite component 2.1 can serve. So can the plastic element 12 Supernatants, extensions and the like.

In 3 is a sectional view of the composite component 2.1 according to 2 shown. The composite component 2.1 includes the three components 4 . 6 and 12 , The molding 4 is between the two plastic elements 6 and 12 arranged. It can also be seen that the second plastic element 12 is arranged in a border area. In particular, by the second plastic element 12 at least the recess 8th covered.

4 shows a schematic partial view of a first embodiment of an injection mold in the closed state according to the present invention. As can be seen, in particular a section of the injection molding tool is in the region of the at least one recess 8th of the molding 4 shown.

The injection mold comprises two tool halves 14 and 16 , The first tool half 14 may be the injector side and the second tool half 16 can be the ejector side. The ejector side can be movably mounted. In this way, the injection mold can be opened, for example, a plastic film 4 in the first tool half 14 insert or a manufactured composite component 2 . 2.1 to be taken out, and closed for injection molding. In the present case, the injection mold is shown in the closed state.

In the first tool half 14 is at least one injection device 18 as an injection molding nozzle, arranged. For example, as an injection device 18 provided a hot runner nozzle. The injection device 18 also has an injector core 20 on. This is in particular by a projection 26 formed and represents the end of the injection device 18 represents.

In addition, in the illustrated tool half 14 Openings 22 , such as holes arranged. The openings 22 may be connected to a vacuum system (not shown) to create a vacuum. With the help of the negative pressure, for example, a foil to be backfilled 4 be kept in a preferably constant position. Alternatively or complementary to the openings shown 22 for the application of a negative pressure, a porous tool steel (sintered steel) can be used, via which the negative pressure for fixing the film to be backfilled 4 is transported to the film surface. The advantage here is that due to the small cross-sectional area of the pores on the tool surface, there is no risk that in the case of incorrect positioning of the film 4 Melt (over the pores) can penetrate into the tool.

As already described, the injector core can 20 by a projection 26 be formed. The lead 26 of the injector core 20 can get into the recess 8th extend. In other words, the molded part 4 on the lead 26 of the injector core 20 be hung. The lead 26 of the injector core 20 can amount to the tool half 14 stand out, at least the thickness 24 of the molding 4 equivalent.

In the present case, the lead closes 26 with the molding 4 especially flush, so does not stick out or stands back. By the flush completion of the molding 4 with the injector core 20 The position can be safely maintained during the injection molding process. The plastic melt 6 can about the molding 4 flow and connect materially with this. Overspraying and wrinkling can be avoided.

According to other variants of the present invention, the projection 26 even with a larger amount than the thickness of the molding 4 be formed.

As already described, the projection can 26 or the injector core 20 encircling the contour of the recess 8th exhibit. Preferably, the molding 4 a positive connection with the injection core 20 received. For example, a fit dimension can be selected with a tolerance between 0.1 to 0.5 mm. In a positive connection, the vacuum holes 22 omitted, as a secure holding of the molding 4 can be ensured by the positive locking (without further measures). Overjections can be avoided particularly reliably.

5 shows a partial section of a closed injection mold in an optional further injection molding step. For example, the composite component 2 which one with a plastic melt 6 back-injected molded part 4 comprises introduced into a second Kavitat. The transfer can be done for example with a turntable, a turning plate, a sliding cavity, an index plate or similar device.

The tool half 14.1 again comprises at least one injection device 18.1 , like a hot runner (possibly with sprue). It may be another plastic melt 12 behind the first plastic element 6 and the molding 4 be sprayed. In particular, the sprue area of the previous injection molding step can be covered. So can the 5 be taken that at least the recess 8th with the plastic melt 12 can be covered.

An exemplary embodiment of the inventive method is described below with the aid of 6 explained in more detail. In 6 a flowchart of an exemplary embodiment of the injection molding is shown.

In a first step 601 can at least one molding 4 to be provided. The molding 4 , such as a plastic film, can be introduced into the injection mold. For example, a plastic film 4 on the at least one injector core 20 suspended and optionally held in position by negative pressure. Then the injection mold can be closed.

It is understood that before the provision of the molding 4 this can be preformed, reshaped, trimmed, coated and / or printed accordingly. For example, further elements, such as wires that can serve for heating or as an antenna, can be arranged. In addition, at least one recess 8th in the molding 4 be introduced. The recess 8th in particular, depending on the circumferential contour of the Injektungsanrichtungskerns 20 be formed.

In the closed state of the injection mold, the injector core is 20 at least flush with the molding 4 arranged.

In a next step 602 becomes the molding 4 with a plastic melt 6 back-molded. The plastic melt 6 flows behind the plastic film 4 and in particular, fills the entire area between the second mold half 16 and the plastic film 4 out.

After the plastic melt 6 cohesive with the molding 4 has connected and is cured, the composite component 2 be removed.

Optionally, in a further step 603 the composite component 2 with another plastic melt 12 be back injected. For example, this can be from a plastic melt 6 back-injected molding 4 existing composite component 2 be converted into a second cavity. Then another plastic melt 12 behind the first plastic element 6 and the molding 4 be sprayed (step 603 ). In particular, the sprue area of the previous injection molding step 602 be covered.

It is understood that further injection molding steps can follow. Furthermore, it is understood that the composite component 2.1 can be subjected to further processing steps after demolding for example, a scratch-resistant and / or weather-resistant composite component 2.1 to accomplish.

7 shows a schematic sectional view of the manufactured composite component 2.1 ,

In 8th is another exemplary embodiment of a composite component 2.2 shown in accordance with the present invention. In contrast to the composite component 2.1 according to 2 includes the composite component 2.2 two moldings 4.1 and 4.2 The moldings 4.1 and 4.2 may be made of the same material and be formed, for example, as a functional film.

At least the molding 4.1 is with a recess 8th Mistake. Preferably, the further molded part 4.2 no recess on. The first plastic element 6 is in the present exemplary embodiment between the moldings 4.1 and 4.2 arranged. When as moldings 4.1 and 4.2 two functional films 4.1 and 4.2 are provided, thereby additional functions in the composite component 2.2 to get integrated. For example, a Scheibenkorper be provided with a double-sided heating to z. B. to remove a fog from the inside and ice from the outside.

9 shows the composite component 2.2 in a sectional view. In particular, the 9 be taken that the first plastic element 6 in the present embodiment between the molding 4.1 and the molding 4.2 is arranged.

10 finally shows a partial section of a closed injection mold with the moldings 4.1 and 4.2 , Through the at least one recess 8th in the molding 4.1 can the plastic melt 6 between the two moldings 4.1 and 4.2 be sprayed and deal with the moldings 4.1 and 4.2 connect in particular cohesively.

In a further step, not shown, the composite component 2.2 comprising the moldings 4.1 and 4.2 and the plastic element 6 with another plastic melt 12 be back-injected, as previously described.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 20121744 U1 [0004]
• DE 102005032664 A1 [0004]
• DE 102005009007 A1 [0008]

Claims (15)

Method for producing a composite component ( 2 . 2.1 . 2.2 ) with an injection mold, comprising: - providing at least one molded part ( 4 . 4.1 ), and - injection molding of the molding ( 4 . 4.1 ) with a first plastic melt ( 6 ) by at least one injection device ( 18 ), characterized in that the molded part ( 4 . 4.1 ) by at least one in the molded part ( 4 . 4.1 ) provided recess ( 8th ) through with the first plastic melt ( 6 ) through the injection device ( 20 ) is back-injected. A method according to claim 1, characterized in that - at least the first plastic melt ( 6 ) is made of a transparent plastic material, and / or - that the molded part ( 4 . 4.1 ) is made of a transparent plastic material or of a partially transparent plastic material. Method according to claim 1 or 2, characterized in that the molded part ( 4 . 4.1 ) is a film, in particular a functional film is. Method according to one of the preceding claims, characterized in that the recess ( 8th ) in a peripheral area ( 10 ) of the molded part ( 4 . 4.1 ) is provided. Method according to one of the preceding claims, characterized in that at least the recess ( 8th ) in the molded part ( 4 . 4.1 ) after injection with the first plastic melt ( 6 ) with a second plastic melt ( 12 ) is injected behind. Method according to claim 5, characterized in that the edge region ( 10 ) of the molded part ( 4 . 4.1 ) with the second plastic melt ( 12 ) is injected behind. Method according to one of the preceding claims, characterized in that the recess ( 8th ) in the molded part ( 4 . 4.1 ) is shaped such that the shape of the recess ( 8th ) to a form of injector core ( 20 ) of the injection device ( 18 ) corresponds. Method according to claim 7, characterized in that the recess ( 8th ) in the molded part ( 4 . 4.1 ) to the injector core ( 20 ) of the injection device ( 18 ) corresponds such that the injector core ( 20 ) of the injection device ( 18 ) in a form-fitting manner with the molded part ( 4 . 4.1 ) is connectable. Method according to claim 7 or 8, characterized in that the molded part ( 4 . 4.1 ) has a thickness such that the value of a protrusion ( 26 ) of the injector core ( 20 ) of the injection device ( 18 ) equal to the value of the thickness of the molded part ( 4 . 4.1 ) or greater than the value of the thickness of the molding ( 4 . 4.1 ). Method according to one of the preceding claims, characterized in that for holding the molded part ( 4 . 4.1 ) a negative pressure in an injection device ( 18 ) tool half ( 14 ) is produced. Method according to one of the preceding claims, characterized in that - at least one further molded part ( 4.2 ), and - that the first plastic melt ( 6 ) by the in a molding ( 4.1 . 4.2 ) provided recess ( 8th ) between the two molded parts ( 4.1 . 4.2 ) is back-injected. Composite component ( 2 . 2.1 . 2.2 ) produced by a method according to one of the preceding claims. An injection molding tool for carrying out the method according to one of the preceding claims 1 to 11 with a first tool half ( 14 ) and a second tool half ( 16 ), characterized in that in a tool half ( 14 . 16 ) at least one injection device ( 18 ) for the Hiterspritzen at least one molding ( 4 . 4.1 ) by at least one in the molded part ( 4 . 4.1 ) provided recess ( 8th ) is arranged therethrough. Injection mold according to claim 13, characterized in that in at least one mold half ( 14 . 16 ) at least one opening ( 22 ) for generating a negative pressure for holding at least the molded part ( 4 . 4.1 ) is arranged. Injection mold according to claim 13 or 14, characterized in that at least one mold half ( 14 . 16 ) is made of a porous tool steel, in particular of sintered steel.

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