DE102008015852A1 - Heatable plastic pane i.e. panoramic roof, for use as e.g. rear window of motor vehicle, has heating conductor, electric conductor and contact element, where contact element is arranged between electric conductor and heating conductor - Google Patents

Abstract

The pane (1) has a heating conductor (2), an electric conductor (3) and a contact element (4), where the contact element is arranged between the electric conductor and the heating conductor. A contact surface between the heating conductor and the contact element is larger than a contact area between the electric conductor and the contact element. The contact element is made of metal such as copper. The contact element is designed as a foil or sheet. The thickness of the contact element is in the range of 0.1-1 millimeter. An independent claim is also included for a method for manufacturing a heatable plastic pane.

Description

The The invention relates to a heatable plastic disc for motor vehicles with at least one heating conductor.

Of the Material glass was for Motor vehicle windows in the past so far without Competitor. Because of the weight saving and the design freedom today there are also fixed side windows and panoramic roofs Plastic. Rear windows made of plastic have not yet enforced because a functioning heater is not yet on the Market available is. There is a particular need to heatable Plastic disc with at least one heating conductor reliable to contact. A soldering of the heating conductor with an electrical line connecting the heating conductor feeding with electricity is problematic because the penetration of soldering heat into the Plastic disc to irreversible damage or at least too visually adverse effects or marks on the outside to lead can be seen in the form of faults, surface riots, etc. and the disc quality destroy irreparably. In addition, the feed is great Amperages over the electrical conduction in the heating conductor is problematic because it has a considerable local heat input caused at the contact point and heat over the plastic disk in the pane level i. d. R. is poorly dissipated.

Of the Invention is based on the object, a heated plastic disc for motor vehicles provide that can be produced with little effort and high quality is, reliably connected is while achieving a sufficient heat output.

Around to solve this task the invention provides the heated plastic disc for motor vehicles according to claim 1, comprising: at least one heating conductor, an electrical line and a contact element, wherein the contact element arranged between the electrical line and the heating conductor is.

• A) eine „Pufferfunktion”, um einen punktuell und kurzzeitig erfolgenden Wärmeeintrag, z. B. durch Lötwärme, zu Puffern bzw. im Wesentlichen aufzunehmen und nicht unmittelbar an die Kunststoffscheibe abzugeben, und
• B) eine „Verteilerfunktion”, um den Strom, der über die elektrische Leitung in den Heizleiter einspeist wird, großflächig auf den Heizleiter zu verteilen, so dass eine lokale Überhitzung der Kunststoffscheibe („hot spot”) an der Kontaktfläche verhindert wird.

The contact element arranged between the electrical line and the heating conductor essentially fulfills two functions:

• A) a "buffer function" to a punctual and short-term heat input, z. B. by soldering heat to buffers or substantially absorb and not directly to the plastic disc, and
• B) a "distribution function" to distribute the current that is fed via the electrical line in the heating element, over a large area on the heating element, so that a local overheating of the plastic disk ("hot spot") is prevented at the contact surface.

The "buffer function" is on a heat storage capacity of the contact element coupled. The bigger the Heat storage capacity of the contact element is, the better is the "buffer effect". The heat storage capacity of the contact element is calculated according to the mass of the contact element and the specific Heat storage capacity of the material of the contact element.

The "distributor function" is on an electrical conductivity and a thermal conductivity coupled to the contact element. The greater the electrical conductivity and thermal conductivity of the contact element, the better is the "distribution effect". The electric conductivity and thermal conductivity of the contact element is calculated according to the line cross section and the specific electrical conductivity and thermal conductivity the material of the contact element.

The Contact element is preferably designed and to the heating element connected, that there are only such amounts of heat to the heating element or the plastic disc emits which the heating conductor or the plastic disc not sustainably damage. In particular, the contact element by a soldering heat or Lötenergie no over one for the plastic disc critical temperature value, z. B. + 100 ° C warm. To the contact element should have a correspondingly high heat storage capacity.

The Contact element is preferably also designed such that during Current transfer from the contact element on the heating conductor no local overheating the plastic disk takes place in the region of the contact point.

It can be helpful if there is a contact surface between the heating conductor and the contact element is greater than a contact surface between the electrical line and the contact element. This will be a size Heat transfer surface between created the heating element and the contact element and the beginning mentioned "distributor function" of the contact element will be further improved.

It may prove to be advantageous when the contact element a larger specific thermal conductivity and / or having a greater specific heat storage capacity as the heating conductor. The larger specific thermal conductivity accomplishes a better distribution of heat over the contact element than over the Heating conductor. The larger specific Heat capacity improved the "buffer function" of the contact element during short-term exposure to large amounts of heat.

It can be cheap prove, when the contact element made of metal, preferably copper is. Metals, in particular copper, have i. d. R. a special high specific thermal conductivity and / or a particularly high specific heat storage capacity on and are as materials for the contact element ideally suited.

It can be useful be when the contact element is formed as a foil or sheet and a thickness between 0.01 mm and 2.0 mm, preferably between 0.05 mm and 1.5 mm, preferably between 0.1 and 1 mm, more preferably about 0.2 mm. Such embodiments of the contact element are easy to process and offer optimal properties in terms of the thermal conductivity and / or the heat storage capacity. It can also useful be when the contact element has a width between 0.1 cm and 10.0 cm, preferably between 0.5 cm and 5.0 cm, preferably between 1.0 and 2.0 cm, more preferably 1.5 cm. In addition, can it useful be when the contact element has a length between 0.5 cm and 100.0 cm, preferably between 1.0 cm and 50.0 cm, preferably between 5.0 and 10.0 cm, more preferably 10.0 cm.

It may be advantageous if the contact element substantially band-shaped or in strips is formed and extends substantially along the heating conductor extends. Thus, the "distribution function" and "buffer function" of the contact element can be optimally connect.

It but can also be advantageous if the contact element on the Heat conductor is glued. For gluing the contact element the heating element is no heat required. This prevents irreparable damage to the plastic disc become.

It may prove helpful if the contact element is a tinning having. The tinning, preferably as a local admission of the contact element with tin, in particular solder, is formed forms a predestined contact point to connect the electrical line to the contact element. The tinning can already take place before attaching the contact element to the heating element. This is for soldering the electrical line to the contact element only a small Lötenergie required.

It may prove helpful when the electrical line is on the contact element is soldered. Over a soldered point can be great Transmit currents. In addition, the electrical wire by soldering is durable, strong and reliable connected to the contact element.

It can come in handy prove when the electrical line at the tinning with the Soldered contact element is. At the tinning can be soldered without problems, without it too irreparable damage comes on the plastic disc, because the tinning itself as a heat storage acts and absorbs soldering heat. Alternatively, the compound but also z. B. by welding or Gluing be made.

It can be handy if the heating element is on a plastic layer the plastic disc is printed and a thickness between 1 and 20 μm, preferably between 5 and 10 μm, preferably 6 microns. Such a thinner Heating conductor can be easily embedded between adjacent laminate layers become.

One Another preferred aspect of the invention relates to a method for producing the heatable plastic disc according to one of previous versions, comprising the steps of: A) attaching the contact element to the heating conductor; B) covering the contact element with a plastic layer; C) exposing at least a portion of the contact element below Opening of the plastic layer; and D) attaching the electrical lead at the exposed portion of the contact element. This manufacturing process allows one inexpensive Production of the heated plastic disc, z. B. as a "laminate disk", and a Reliable contacting of the plastic disc over the electrical line.

It may prove helpful if step C) includes: milling through the Plastic layer and milling a (pre-) tinning of the contact element. In the area of (pre-) tinning Can an electrical wire or strand of wire quickly and easily with low soldering energy soldered become.

One Another preferred aspect of the invention relates to a method for producing the heatable plastic disc according to one of previous versions, comprising the steps: A ') attaching the electrical line to the contact element; B ') attaching the contact element on the heating conductor; C ') Injection of a plastic layer, so that the electric Line extends through the plastic layer therethrough. This manufacturing process allows a cost-effective Production of the heated plastic disc, z. B. as a "film hinterspritzte Disc", and a reliable contact of the plastic disc over the electrical line.

Brief description of the figures

1 shows a view of a heatable plastic disc according to the invention from the Au ßenseite;

2 shows a sectional view of a heatable plastic disc according to the invention according to a first embodiment;

3 shows a sectional view of a heatable plastic disc according to the invention according to a second embodiment; and

4 shows a sectional view of a heatable plastic disc according to the invention according to a third embodiment.

Detailed description the preferred embodiments

The invention relates to a heatable plastic disc 1 for motor vehicles, comprising: at least one heating conductor 2 , an electrical line 3 and a contact element 4 , wherein the contact element 4 between the electrical line 3 and the heating conductor 2 is arranged.

1 shows a view of a heatable plastic disc according to the invention 1 from the outside. There, a preferred Heizleiteranordnung is shown.

A black border 8th with a width of about 1 to 10 cm, preferably about 5 cm, runs along the outer edge of the plastic disc 1 , Two main heating conductors 2 (Busbars) with a width of about 0.5 to 5 cm, preferably about 2.5 cm are on opposite sides of the plastic disc 1 imprinted in the black border area. Branch heating conductor 2 extend substantially straight, substantially parallel to each other and preferably in parallel between the two main heating conductors 2 (Busbars), the branch heating conductor 2 a Heizleiterabstand of about 20 mm; a heating conductor width of approx. 1.0 mm; and have a Heizleiterdicke of about 6 microns. The branch heating conductor 3 run in the example of 1 horizontal. For example, the design can also be rotated 90 ° so that the branch heating conductors 2 run vertically. The main heating conductor 2 (Busbars) and branch heating conductors 2 are, preferably by screen printing, on a plastic layer of the plastic disc 1 printed.

The contact element 4 is preferred in the black border area on the main heat conductor 2 (Busbars) glued. The following is the main heating conductor 2 on which the contact element 4 is preferably glued, simplifying sometimes as heating conductor 2 designated.

In the embodiments described below, the contact element 4 each self-adhesive copper foil with a thickness of about 0.2 mm, the entire surface of each of the two main heating conductors 2 (Busbars) on opposite side edges of the plastic disc 1 is glued on. The contact element 4 is formed substantially band-shaped or strip-shaped. It has a width of about 2.5 cm at a length of about 50 cm, and extends substantially along the heating element 2 , A contact surface between the heating conductor 2 and the contact element 4 is larger than a contact area between the electric wire 3 and the contact element 4 , The contact element 4 also points to the main heat conductor 2 facing away from a tinning 10 with solder on, on which the electrical line 3 with the contact element 4 is soldered.

The heating conductor 2 is, preferably by screen printing, on a plastic layer 5 the plastic disc 1 (either directly or indirectly on the black border 8th ) and has a thickness of about 6 microns. For printing, an electrically conductive paste with silver particles is used as the (screen) printing ink.

The electrical line 3 is preferably formed as a sheathed or insulated Drahtanschlusslitze.

The plastic layer 5 to which the heating conductor 2 is printed, is formed for example as a film, as a plate or as an injection molded part. On the plastic layer 5 For example, the black border will preferably be in the pattern 1 applied in the edge region, z. B. imprinted.

The preferred embodiments of the invention will be described below with reference to FIGS 2 to 4 described:

2 shows a sectional view of the heatable plastic disc according to the invention 1 according to the first embodiment.

The plastic disc 1 according to 2 includes a plastic layer 5 made of PMMA with a thickness of 1 mm, a black border 8th , a heating conductor 2 (Busbars), a copper foil with a thickness of 0.2 mm as a contact element 4 , a melt adhesive layer 7 made of TPU with a thickness of 1.2 mm, and a plastic layer 6 made of PC with a thickness of 3 mm. The plastic layer 6 made of PC and the melt adhesive layer 7 made of TPU have recesses through which with the contact element 4 connected electrical line 3 from the plastic disc 1 is led away. The electrical line 3 is with the contact element 4 on a pre-tinning 10 soldered.

The plastic disc 1 according to 2 becomes made as follows: The black border 8th is applied to an edge region of the plastic layer in a width of about 5 cm on the plastic layer 5 printed. The heating conductor 2 is, preferably by screen printing, z. B. in an arrangement after 1 printed. The self-adhesive contact element 4 is completely on the heating element 2 glued. A semi-finished product comprising the plastic layer 5 , the black border 8th , the heating conductor 2 and the contact element 4 , is then in an autoclave or in a press with the melt adhesive layer 7 and the plastic layer 6 connected to a laminate disk. The electrical line 3 gets through the recesses in the plastic layer 6 and the melt adhesive layer 7 with the contact element 4 connected and on a pre-tinning 10 soldered with a low energy consumption.

3 shows a sectional view of the heatable plastic disc according to the invention 1 according to the second embodiment.

The plastic disc 1 according to 3 essentially comprises the same layer structure as the first embodiment according to 2 , with the difference that the plastic layer 6 from PC and / or the melt adhesive layer 7 TPU initially have no recesses. The plastic layer 6 from PC and / or the melt adhesive layer 7 made of TPU are only subsequently broken to the electrical conductor 3 to the contact element 4 to join.

• A) Anbringen des Kontaktelements 4 an dem Heizleiter 2;
• B) Bedecken des Kontaktelements 4 mit einer Kunststoffschicht 6;
• C) Freilegen zumindest eines Abschnitts des Kontaktelements 4 unter Durchbrechung der Kunststoffschicht 6, insbesondere Durchfräsen der Kunststoffschicht 6 und Anfräsen einer Verzinnung 10 des Kontaktelements 4; und
• D) Anbringen der elektrischen Leitung 3 an dem freigelegten Abschnitt des Kontaktelements 4.

The plastic disc 1 according to 3 is made as follows:
The method for producing the heatable plastic disc 1 to 3 includes the steps:

• A) Attaching the contact element 4 on the heating conductor 2 ;
• B) covering the contact element 4 with a plastic layer 6 ;
• C) exposing at least a portion of the contact element 4 under breakthrough of the plastic layer 6 , in particular through milling of the plastic layer 6 and trimming a tinning 10 of the contact element 4 ; and
• D) Attaching the electrical line 3 at the exposed portion of the contact element 4 ,

Before step A), the plastic disc 1 according to 3 essentially as the first embodiment according to 2 prepared.

In step A) becomes the self-adhesive contact element 4 all over the heating conductor 2 glued. At a designated contact point of the electrical conductor 3 and the contact element 4 has the contact element 4 even before sticking to the heating conductor 2 a tinning 10 on. This is z. B. solder on the contact element 4 has been applied, in a thickness substantially the thickness of the hot melt adhesive layer 7 is equal to or even thicker than the melt adhesive layer 7 ,

In step B), the plastic layer 5 , the black border 8th , the heating conductor 2 , the contact element 4 , the hot melt adhesive layer 7 and the plastic layer 6 in an autoclave or in a press connected to a laminate disk (lamination), wherein the contact element 4 with the plastic layer 6 is covered.

In step C) the tinning is 10 exposed after lamination. This is the plastic layer 6 with a milling tool, z. B. a face milling cutter, durchfräst and tinning 10 of the contact element 4 milled.

In step D), the electric line 3 through the milled opening in the plastic layer 6 at the tinning 10 with the contact element 4 soldered.

4 shows a sectional view of the heatable plastic disc according to the invention 1 according to the third embodiment.

The heated plastic disc 1 according to 4 is a so-called "foil-injected plastic disc". In this embodiment, the plastic disc comprises 1 a plastic layer 5 , a black border 8th , a heating conductor 3 , a contact element 4 and a back-injected plastic layer 6 , The back-injected plastic layer 6 is preferably made of PC and has a thickness between 3 mm for normal and 15 mm for safety discs.

• A') Anbringen der elektrischen Leitung 3 an dem Kontaktelement 4;
• B') Anbringen des Kontaktelements 4 an dem Heizleiter 2; und
• C') Hinterspritzen einer Kunststoffschicht 6, so dass sich die elektrische Leitung 3 durch die Kunststoffschicht 6 hindurch erstreckt.

A method for producing the heatable plastic disc 1 to 4 includes the steps:

• A ') Attaching the electrical line 3 on the contact element 4 ;
• B ') attaching the contact element 4 on the heating conductor 2 ; and
• C ') Injection of a plastic layer 6 so that the electrical line 3 through the plastic layer 6 extends through.

Before step A '), the plastic disc 1 according to 4 essentially as the first embodiment according to 2 prepared.

In step A '), the electric line 3 on a pre-tinned contact element 4 at least one solder joint / tinning 10 soldered.

In step B '), the already pre-tinned and with the electrical line 3 soldered contact element 4 all over the heating conductor 2 glued. The steps A ') and B') can also be reversed.

In step C '), the semifinished product is introduced into an injection mold and the plastic layer 6 is back-injected, so that the electrical line 3 through the plastic layer 6 extends through. When inserting and during the injection process, that of the contact element 4 projecting electrical line 3 held by a movable jaw. After the back of the plastic layer 6 The clamping jaw and the foil-injected plastic disc are released 1 including the electrical line 3 will be released. To avoid that injection molding, z. As polycarbonate, during injection molding runs into the jaws and the electrical line 3 unintentionally isolated, it is appropriate to the electrical line 3 to remain isolated in this area and only after the completion of the plastic disc 1 remove the insulation and then contact with a cable lug.

The safe contacting of the advantages of the heated plastic disc 1 be used at all. Due to the planar power transition of the contact element 4 on the heating conductor 2 is a very reliable heating and contacting possible. The connection of the plastic disc 1 To a vehicle electrical system can, as usual, with the known connection techniques on the electrical line 3 be accomplished.

The plastic layers 5 . 6 the plastic disc 1 are preferably made substantially of polycarbonate (PC), polymethylmethacrylate (PMMA), polymethacrylmethylimide (PMMI) or cyclo-olefin copolymers (COC). But it can also be used other plastics.

In a motor vehicle, the heated plastic disc 1 according to one of the preceding embodiments preferably used as a rear window. Other applications of the heatable plastic disc according to the invention 1 but are not excluded. Thus, the heatable plastic disc according to the invention 1 z. B. also be designed as a motor vehicle panoramic roof.

Claims (15)

Heatable plastic disc ( 1 ) for motor vehicles, comprising: at least one heating conductor ( 2 ), an electrical line ( 3 ) and a contact element ( 4 ), wherein the contact element ( 4 ) between the electrical line ( 3 ) and the heating conductor ( 2 ) is arranged. Heatable plastic disc ( 1 ) according to claim 1, characterized in that a contact surface between the heating conductor ( 2 ) and the contact element ( 4 ) is greater than a contact area between the electrical line ( 3 ) and the contact element ( 4 ). Heatable plastic disc ( 1 ) according to one of the preceding claims, characterized in that the contact element ( 4 ) has a greater specific thermal conductivity and / or a greater specific heat storage capacity than the heating conductor ( 2 ). Heatable plastic disc ( 1 ) according to one of the preceding claims, characterized in that the contact element ( 4 ) made of metal, preferably copper, is formed. Heatable plastic disc ( 1 ) according to one of the preceding claims, characterized in that the contact element ( 4 ) is formed as a foil or sheet and has a thickness between 0.01 mm and 2.0 mm, preferably between 0.05 mm and 1.5 mm, preferably between 0.1 and 1 mm, particularly preferably 0.2 mm. Heatable plastic disc ( 1 ) according to one of the preceding claims, characterized in that the contact element ( 4 ) is substantially band-shaped or strip-shaped and extends substantially along the heating conductor ( 2 ). Heatable plastic disc ( 1 ) according to one of the preceding claims, characterized in that the contact element ( 4 ) on the heating conductor ( 2 ) is glued. Heatable plastic disc ( 1 ) according to one of the preceding claims, characterized in that the contact element ( 4 ) a tinning ( 5 ) having. Heatable plastic disc ( 1 ) according to one of the preceding claims, characterized in that the electrical line ( 3 ) to the contact element ( 4 ) is soldered. Heatable plastic disc ( 1 ) according to one of the preceding claims, characterized in that the electrical line ( 3 ) on the tinning ( 5 ) with the contact element ( 4 ) is soldered, welded or glued. Heatable plastic disc ( 1 ) according to one of the preceding claims, characterized in that the heating conductor ( 2 ) on a plastic layer ( 5 ) of the plastic disc ( 1 ) is printed and has a thickness between 1 and 20 microns, preferably between 5 and 10 .mu.m, preferably 6 microns. Method for producing the heatable plastic disk ( 1 ) according to one of the preceding claims, comprising the steps of: A) attaching the contact element ( 4 ) on the heating conductor ( 2 ); B) covering the contact element ( 4 ) with a plastic layer ( 6 ); C) exposing at least a portion of the contact element ( 4 ) under opening of the plastic layer ( 6 ); and D) attaching the electrical line ( 3 ) on the exposed portion of the contact element ( 4 ). The method of claim 12, wherein step C) comprises: milling the plastic layer ( 6 ) and milling a tinning ( 5 ) of the contact element ( 4 ). Method for producing the heatable plastic disk ( 1 ) according to one of claims 1 to 11, comprising the steps of: A ') attaching the electrical line ( 3 ) on the contact element ( 4 ); B ') attaching the contact element ( 4 ) on the heating conductor ( 2 ); and C ') injection molding of a plastic layer ( 6 ), so that the electrical line ( 3 ) through the plastic layer ( 6 ) extends therethrough. Motor vehicle with a heatable plastic disc ( 1 ) according to one of claims 1 to 11.