DE3644434A1 - Door leaf, in particular for cold stores - Google Patents

Abstract

A door leaf, in particular for cold stores, having a core (6) which consists of foam and a casing which consists of glass-fibre-reinforced plastic is to be improved with respect to the prior-art two-shelled construction type. It is proposed that the casing be composed of one piece and enclose the core (6) on all sides in a seamless manner. For this purpose, use is made of the so-called resin injection process. Glass mats (8), followed by the foam core and further glass mats (9) on top of this are introduced into the bottom half (1) of a two-part mould. After closing the mould, the latter is evacuated and supplied, via a filling channel (3), with liquid plastic until the latter emerges at the intake connection stub (5) without bubbles (see drawing). <IMAGE>

Description

The invention relates to a door or door leaf, especially for cold rooms, with a core made of foam and a jacket made of glass fiber reinforced plastic. The known insulating doors of this type, which advantageously light, impact resistant and resistant to most Chemicals are made up of two shells with their own Edges are attached to each other and the Include foam body. Usually the of the cavity formed in the two shells and this causes a mutual connection of the shells.

However, the seam running all around carries the risk of that moisture and dirt penetrate into the door interior and destroyed the foam body. But above all it is Strength of the door and its dimensional stability at extreme Differences in temperature are affected. The two bowls should therefore be tight and tight at the joint connected, which is structurally difficult and the Manufacturing more expensive.

The invention has for its object a door or To propose a door leaf of the type described in the introduction, that keeps its shape and is uniformly stable on all sides is against the influences of moisture and chemicals and that in series production is quick and easy can be made.

This object is achieved in that the Glass fiber reinforced plastic jacket made from one piece exists and surrounds the core on all sides and seamlessly.

For this, the use of the so-called Resin injection method proposed, in which a  an evacuated hollow form Glass fiber structure by means of an inflowing and the shape filling plastic is soaked, the in the Form foam core to be inserted either Panel material cut or to achieve the highest Dimensional accuracy in a previous process in a special shape is foamed.

With the resin injection process, too The plastic flows called vacuum injection processes from one along the edge of the mostly flat molding leading filling channel to the middle. The inserted Glass fiber mat or the like is thus in the direction the flat extension of which flows through the plastic, which is relatively slow and a high vacuum required. The peculiarity of the application of this Process on the manufacture of door leaves with Foam insert is that this is flat Advance of the plastic from the edge on both sides the foam core has to take place. Consequently you would have a suction port on the inside of the door and attach to the outside of the door, but this is what Manufacturing facility would make a lot more complicated and would have the disadvantage that on both sides of the door Stalk remains, the removal of which is not without a trace is possible.

According to the invention it is therefore proposed that the Foam core in the middle area at least one has continuous transverse channel through which the air from the side of the Foam core is suctioned off and through after filling the shape of the plastic reaches the suction nozzle. Thereby you get one on at least one side without rework completely smooth door leaf.

Embodiments of the invention are as follows explained using the drawing.

In detail shows

Fig. 1 is a schematic sectional view of a mold and of a door panel therein,

Fig. 2 shows a cross-section of the edge portion of the lower mold half with the deposits prior to the injection process,

Fig. 3 shows the edge area of another shape for a door leaf without a fold.

The mold according to Fig. 1 consists of a lower part (1) and an upper part (2) being formed in the top of a cross-sectionally triangular filling channel (3) which surrounds the mold cavity rings. A filler neck ( 4 ) of a pump is connected to the filler channel and is connected to a metering and mixing system for providing a hardenable plastic. Approximately in the middle of the upper part of the mold ( 2 ) there is a suction nozzle ( 5 ) which is connected to a high-performance vacuum pump.

In the mold there is a foam core ( 6 ) that has been specially manufactured beforehand and which has several transverse channels ( 7 ) in the middle, ie in the vicinity of the suction nozzle ( 5 ), which completely penetrate the foam core. This can be pierced or pierced to produce the transverse channels ( 7 ). The underside of the foam core ( 6 ) is encased by a glass fiber mat ( 8 ) and the top by a glass fiber mat ( 9 ).

The method for producing a door leaf with the molding device described proceeds as follows. First, the two cleaned mold halves ( 1 and 2 ) are sprayed on the inside with a cover layer (gel coat), which also contains lightfast color pigments. The surface layer has to dry for some time. Then glass fiber mats ( 8 ), precisely trimmed with regard to their overhang, are placed in the horizontally designed lower mold half ( 1 ). Then the foam core ( 6 ) is fitted onto the glass fiber mats ( 8 ) and pressed into the mold, the edges of the glass fiber mats bending up or having to be pulled up. These edges are then bent inwards over the fold. Then further glass fiber mats ( 9 ) are placed on the foam core ( 6 ) and the glass fiber mats ( 8 ) are bent downward overlapping slightly at the edges.

After cleaning the mold edges, the upper mold half ( 2 ) is now placed, whereby the glass fiber mats are also pressed against the foam core ( 6 ) in the edge area, but - according to the exact dimensioning of the foam core ( 6 ) - are only compressed to a small extent. The naturally required precautions for sealing the mold are not shown in this schematic representation.

When the filler neck ( 4 ) is initially closed, the air is drawn off at the suction neck ( 5 ) and a vacuum of about 800 millibars is created. Then you can flow through the filler neck ( 4 ) viscous plastic into the annular filling channel ( 3 ), from where it penetrates through the all-round slot between the filling channel ( 3 ) and the mold interior in the glass fiber mats ( 8 and 9 ). As a result of the vacuum and under the pressure of the injection pump, the plastic in the mats is distributed over the entire surface, the surface currents on the underside and on the top of the foam core ( 6 ) being distinguished. Finally, the concentric flows meet at the suction nozzle ( 5 ) or at the bottom of the transverse channels ( 7 ), which also open at the suction nozzle ( 5 ). The filling process is only finished when bubble-free plastic emerges from the suction nozzle ( 5 ). The plastic is preferably colored through in the same color as the cover layer.

During the hardening process, the cover layer connects to the plastic and stands out from the mold during molding. It then forms an exceptionally scratch-resistant surface of the door leaf. After shaping, the stub created by the suction nozzle ( 5 ) on one side of the door leaf and the flange-like filling channel ( 3 ) running all around are removed.

In the presence of multiple forms and organized Workflow is a series production with very little Time expenditure per piece possible. The previously required The foaming process is omitted. The one with the Foam core also firmly connected outer jacket glass fiber reinforced plastic, preferably polyester, is bubble-free and of uniform strength, so that the door leaf does not warp.  

• 1 lower part
  2 top
  3 filling channel
  4 filler neck
  5 suction ports
  6 foam core
  7 cross channel
  8 glass fiber mat
  9 glass fiber mat

Claims (5)

1. Door or gate leaf, especially for cold rooms, with a core made of foam and a jacket made of glass fiber reinforced plastic, characterized in that the jacket consists of one piece and surrounds the core ( 6 ) on all sides and seamlessly. 2. Use of the so-called resin injection process, in which a glass fiber structure ( 8 , 9 ) enclosed in an evacuated hollow mold ( 1 , 2 ) is penetrated by means of an inflowing plastic that fills the mold, for producing a door or door leaf with a foam core ( 6 ) . 3. A method for producing a door or gate leaf according to claim 1, characterized in that the lower half ( 1 ) of a two-part hollow mold is designed with glass fiber mats ( 8 ), that the foam core ( 6 ) is then placed on these glass fiber mats ( 8 ) and is pressed into the mold ( 1 ), the edges of the glass fiber mats ( 8 ) rising laterally, so that the foam core ( 6 ) is then covered with further glass fiber mats ( 9 ) and the upper half ( 2 ) of the mold is placed, which is opposite the The lower half ( 1 ) is sealed and forms with this a circumferential filling channel ( 3 ) connected to the interior of the mold by one or more slot-shaped connecting openings, so that the mold is then evacuated and the liquid plastic is injected into the filling channel ( 3 ) until bubble-free plastic at an opening ( 5 ) located in the middle of a mold half ( 2 ), in the vicinity of which at least one transverse channel ( 7 ) exits the foam core ( 6 ) passes through, and then the plastic is allowed to harden, the mold is opened and the flange-like filling channel ( 3 ) and the stem formed at the suction opening ( 5 ) are removed. 4. The method according to claim 3, characterized in that the inner surfaces of the mold halves ( 1 , 2 ) receive a coating before inserting the glass fiber mats ( 8 , 9 ), which connects to the plastic and forms the outer surface of the door leaf after molding, 5. Door or door leaf according to claim 1, characterized in that the foam core ( 6 ) contains anchoring parts for door hinges, handles, etc.