DE10124061B4 - Process for the production of plastic foam boards of large thickness - Google Patents

Abstract

A method for connecting at least two starting plates made of plastic foam to a new plate, in particular of alternative or HCFC-free driven plastic foam plates as starting plates to new plates with a minimum thickness of 70 mm, in particular also polystyrene foam plates, characterized in that
a) starting plates are used which are extrusion skinless at the contact surface and
b) the connection of the output plates is done by solvent welding.

Description

The The invention relates to a method for connecting at least two Plastic foam starting plates to a new plate with a minimum thickness of 70 mm, in particular polystyrene foam boards.

New Energy-saving regulations demand from the client always better thermal insulation. by virtue of the limited availability non-renewable energy sources (Coal, gas, petroleum) All consumers are instructed to save energy. This can be done in the strong dimensions done by better house insulation. Against the background are in the past plastic foam boards with a thickness of more than 100 mm, even with a thickness of 200 mm and more. This is with the HCFC-containing blowing agents for extruder foam without further possible. However, the HFCKW-containing propellants are because of their damaging effect to the ozone layer replaced by alternative propellants.

With The use of alternative propellants has become difficult to manufacture this plastic foam panels give considerable difficulties. From a thickness of 60/70 mm, these difficulties increase greatly.

Also worsen the insulating properties with the use of most alternative Blowing agent when extruding insulation boards. The following will be on polystyrene foam boards (XPS) explained.

The Isolation feature of the XPS hangs very strongly dependent on the cell structure of the foam. This will too determined by the ratio of insulation thickness to nozzle gap. At the same time by narrowing the nozzle gap a necessary Melt pressure in front of the nozzle gap being constructed. This forces compliance with certain nozzle gap limits. This means, the nozzle gap can not open arbitrarily wide be, because with his help, the pressure in the nozzle is generated by the guaranteed is that the propellant is not already in the nozzle for frothing the Melt leads.

at Growing Plate thickness is thereby an increase in the ratio of insulation thickness to nozzle gap. The bigger this ratio becomes, the worse the cell structure gets and the more difficult it is the production of a foam with good insulating properties.

In the past is with the DE 4421016 A1 has been proposed to overcome the above-mentioned difficulties by producing plates with safely attainable thickness and doubling of the plates. A thermal connection between the plates was provided. An editing of the plates on the contact surfaces was not provided. However, this proposal has not been implemented because fusion welding by thermal fusion of the surfaces of two plates at the weld creates a barrier against water vapor diffusion and must be preserved for most applications of the XPS as a thermal insulation product in construction. The barrier layer is formed by the extrusion skins at the contact surfaces of the plates and the additional skirts resulting from the thermal connection.

The welding of foils to thicker products is disclosed in US Pat DE 3541053 A1 , This prior art is not about the DE 4421016 A1 Beyond that, there were doubts as to whether plates were already being formed along the way.

The US 4125424 discloses bonding two unfoamed thin films by thermal lamination.

It It is also known to glue extruded sheets together. There is also a barrier between them connected panels. The barrier layer consists in turn of the extrusion skins, in addition the adhesive layer.

since Endeavors years Experts are concerned with a sufficient product quality of XPS boards. Also The invention has achieved this task. It turns the invention of the unpublished technique of doubling too. This is based on the knowledge that the previous negative experiences through the barrier between the interconnected plates justified are.

• a) extrudierte Ausgangsplatten verwendet werden, die spätestens unmittelbar vor der Verbindung an der Berührungsfläche durch Bearbeitung von der Extrusionshaut befreit werden und
• b) die thermoplastischen Polystyrolschaumplatten durch Quellschweißung verbunden werden.

According to the invention, a diffusibility between at least two polystyrene foam sheets is made by

• a) extruded starting plates are used, which are released from the extrusion skin at the latest immediately before the connection at the contact surface and
• b) the thermoplastic polystyrene foam sheets are joined by solvent welding.

The source welding of polystyrene foam boards is not obvious, because thermoplastic sheets can be joined together by thermal welding. In the inventively provided solvent welding, the welding surfaces are attached by means of a solvent triggers, but not resolved. The correct amount of solvent addition and the exposure time can be determined very accurately before the standard application with a few experiments.

The Connection can be done by pressing the disks to be connected are supported. Partially it is sufficient if only one side of the welded joint is loosened.

As solvent come organic solvents with a boiling point below 150 degrees Celsius into consideration. It come also mixtures of different solvents and mixtures with water into consideration. The deposit of the Mixture components also be greater than 2.

Has proven In experiments, a mixture of acetone and water. The water content was 10% by volume based on the total amount of solvent. In other Examples is the water content between 2 to 30% by volume.

• 1. die Lösungsmittelmoleküle dringen zwischen die Polymerketten.
• 2. Dadurch bekommen die Polymerketten mehr Bewegungsfreiheit (vergleichbar mit dem geschmolzenen Polymer)
• 3. Die Polymerketten der einen Platten können so zwischen die Polymerketten der zweiten Platte eindringen.
• 4. Nach dem Wegdiffundieren der Lösungsmittelelmoleküle verhaken die Polymerketten der einen Platte mit den Polymerketten der zweiten Platte.

Source welding can also be referred to as chemical welding. The process can be described as follows.

• 1. the solvent molecules penetrate between the polymer chains.
• 2. This gives the polymer chains more freedom of movement (comparable to the molten polymer)
• 3. The polymer chains of one plate can thus penetrate between the polymer chains of the second plate.
• 4. After the solvent molecules have diffused away, the polymer chains of one plate entangle with the polymer chains of the second plate.

The Water vapor diffusion is caused by the welding of the invention Boundary layer insignificant to not obstructed.

• a) an den Berührungsflächen und den gegenüberliegenden Schweißflächen oder
• b) einseitig an den Berührungsflächen und durch zusätzliche Maßnahmen, welche die sich ergebende Plattenkrümmung verhindern oder kompensieren.

In this process, a preparation / adaptation of the plates to be joined is a prerequisite. The output plates are processed

• a) at the contact surfaces and the opposite welding surfaces or
• b) on one side of the contact surfaces and by additional measures which prevent or compensate for the resulting plate curvature.

The Adjustment of the welding surfaces before Connecting the plates prevents that at the junction cavities or channels arise, so that a 100% bonding surface is formed and therefore can not store water in the boundary layer. The water would be the Insulating properties of the insulating material decrease.

If a uniform processing at both opposite surfaces the output plates is done, a plate curvature is prevented.

The plate curvature can also be processed by heat treatment with only one-sided processing of the output plates the unprocessed, opposite surface be compensated. It is also conceivable to connect the output plates with sufficient pressure to cancel a curvature. After the connection In particular, the one-sided machined output plates keep at the same thickness mutually in the desired planar shape.

A plate curvature let yourself Also, prevent by two extruded foam strands one-sided at the contact surfaces in the inventive sense machined surface and then, preferably be connected to each other immediately. Because of your Lay length the foam strands easy on each other and can maintain a level course of the strands become.

After their compound of the invention the foam strands to the desired plates cut to length.

By the surface treatment be depending on the quality the starting plates 1 to 10 mm of the plate thickness removed.

As Machining is for example a cutting by milling, planing, Cutting or sawing.

By the machining preferably flat welding surfaces are generated. But it can also curved running welding surfaces generated become.

To the Apply solvent suitable are rollers or nozzles, from which the solvent sprayed becomes. With the rollers leaves Any desired Distribution (both in terms of areal extent and in terms of area) the thickness of the order) of the solvent on the contact surfaces cause. Of the Order can be handled like a paint job. In that Senses are instead of the rollers and order plates after the model suitable for printing plates.

Optional is additional for solvent welding provided a mechanical connection of the plates. The together lying or touching Plates are held together by mechanical connection.

The mechanical connection is through Connects causes that grab on the sides of the plates in the plates and / or embrace the plates. This connection can be point-shaped and / or linear and / or surface-wise. The mounting possible with connecting elements can be modeled on the connection possibilities with the source welding and vice versa.

The Attachment points have a flat extension of the fasteners corresponding extent. The designation corresponds to points the jargon, although it is a matter of area.

Preferably the attachment points are evenly distributed over the contact surface. Optionally distribute the attachment points also according to the distribution of tensile forces in the plates. The expected tensile forces result from the load the plates and / or from the load-independent plate deformations.

The Fastening lines have one of the flat extension of the fasteners corresponding extent. The designation corresponds to lines the jargon, although it is a matter of area.

The linear Attachment can be straight and / or curved. Preferably the attachment lines are straight and across the entire contact area. The Fixing lines can distributed according to the attachment points described above his.

For the distribution the fastening lines are the same as for the distribution of the attachment points.

Optional The fasteners have the form of anchors. Find it at the connecting elements thickened points that the connecting elements the necessary tear resistance in the Give foam.

The tear can also be achieved other than by thickening. For example, have different oppositely inclined fasteners because of their opposing Inclination already an advantageous tear resistance.

Preferably find long stretched, unprofiled on their length fasteners for the connection variant with opposite Tilt application. It can the fasteners by cutting to length simple profile strands or be obtained by cutting out of plates.

Optional The fasteners are also glued in the plates or welded. That increases the tear resistance.

For the fasteners recesses are incorporated into the plates. The recesses are adapted to the fasteners or vice versa.

Cheap is the use of milling cutters for the Production of recesses. Suitable are both side milling cutters also end mill and face milling cutter.

With cutters Can be sideways in the shortest time Time a recess can be made. The milling movement can be CNC controlled or controlled by templates. Simple movements can be also with limit switches.

With the router can also be flat recesses for fasteners in the foam incorporate, in which the fasteners inserted laterally become. Here the shape of the connecting elements and the recesses can still continue to vary. Alternatively, even lateral shapes with lateral ones Curves and / or lines with such shapes towards the middle of the plate combined at the connecting elements.

The different cutters have different working postures with respect to the plate, but in part also characteristic working postures. The end mill can stand differently. The side milling cutter runs with its working plane / direction accordingly the recesses regularly across the Plate longitudinal direction and inclined to the plate plane, possibly also inclined to the plate longitudinal direction. The endmill stands with its working direction like the side milling cutter.

Next the machining by milling cutters is possible Benefits, recesses, etc. through CNC controlled glow wire cutting technology manufacture.

Optional The output plates are processed individually (before stacking) or are the plastic foam sheets with superimposed Edited starting plates.

For the fasteners is preferably the same plastic as provided for the output plates, in XPS disks so XPS. By different extrusion different Weights are incurred. Preferably, the density of the connecting elements and plates not more than 20 kg per cubic meter, better not more than 5 kg per cubic meter.

The connecting elements are wahlwei se used after lateral processing of the plates. Then a sufficient dimensional stability is provided.

Optional the fasteners are used after machining. Then there is an excess of fasteners provided so that the fasteners from the lateral machining be recorded.

The Connection is described above on two output panels. After this inventive method But you can also connect 3 or more plates with each other.

The inventive connection has more surprising There are other benefits, because it reduces the number of to be extruded thickness formats. For example, can be made from sixties plates (the number refers to the thickness in mm below) a 120iger Make a plate or a 180-plate or a 240-plate; from a 50's plate a 100er plate, a 150iger plate, a 200-plate or a 250-plate. In the described make result from a single thickness format by duplication / connection already three or four other commercial thickness formats. It can too different thickness plates are combined, e.g. 50's and 60's plates or 40's and 50's plates if none Danger a plate curvature is caused.

Preferably limited in the sense of the preparation of the invention to the use from 30s to 70s plates. Still more preferably limited the plate making on the use of 40iger, 50iger and 60's output plates. Up to the 60's plate thickness can be In addition, reliably achieve even better lambda values. This results to the invention produced Plate another improvement.

Preferably arises through the compound of the invention a new plate with a minimum thickness of 70 mm.

Optional are used to produce plates with tongue and groove three output plates in the sense of the invention doubled, with the middle output plate opposite the two other output plates (which are in a horizontal position above and lie down) is set so that it jumps back to two sides of the plate and forms a groove and projects on the two sides of the plate and forms a spring. So produced plates can be laid closing, where Feathers of one plate into the grooves of adjacent other plates to grab.

Optional For the production of plates with shiplap two output plates doubled according to the invention, one being the output plate opposite the other output plate is offset. This means, one output plate jumps back and forth on two sides the other remaining pages. This allows the resulting plates likewise closing be laid by the plate on all sides with the shiplap the adjacent other plates overlap.

at the production of tongue and groove or production of shiplap with the duplication according to the invention results in addition a saving in foam, because the traditional packaging of the Foam strands a milling of tongue and groove and shiplap, associated with a corresponding high consumption of the Schaumstrangrandes.

The inventive compound can be applied to various plastics. These include polystyrene, Polyethylene, polypropylene, ethylene and propylene copolymers.

starting boards for the embodiment are conventional produced polystyrene foam boards with a density of 30 to 45 kg per cubic meter. It is in the embodiment first by means of a continuous foam train has been produced in a tandem extrusion line. The tandem extrusion line consists of a primary extruder and a secondary extruder. In the primary extruder is the plastic granules with the usual various additives and processing aids melted and to a homogeneous melt mixed. The resulting melt is carbon dioxide as blowing agent added and the mixture on the way through the extruder on homogenized. That concludes a cool down the melt to extrusion temperature in the secondary extruder.

in the secondary extruder there is a considerable pressure. When discharging the melt through the nozzle the extruder takes place a relaxation of the melt. Consequently expands the propellant and forms in the melt accordingly Its fine distribution of a variety of evenly distributed bubbles / cells.

In another embodiment is instead of a tandem an extrusion line with a single extruder used. It may be different from extruder Type, e.g. Single-screw extruder or twin-screw extruder.

The melt is foamed in a so-called calibrator. It is a metal plate th, which give the resulting foam strand its thickness. After sufficient cooling, the resulting foam strand is freed on one side or on both flat sides by surface treatment of the extrusion skin. This can be done inline with the foam production or after cutting the foam strand to sheets without previous surface treatment. It is also possible to use plates which are cut to length in a known manner from a foam strand which has been processed on two opposite flat sides before being cut to length. The machined and cut plates can be used without intermediate storage or after prior storage, ie connected in accordance with the invention.

The surface treatment takes place in the embodiment by milling. In other embodiments may be another surface treatment Find application.

The surface treatment only one flat side and inline is preferably used when produced in parallel a similar foam strand and processed on the surface so that these foam strands can be connected to each other.

in the embodiment become plates which are processed in the known manner described above and have been stored in a station 1 next to each other and one behind the other on a roller table (consisting of one behind the other arranged rollers) so that they are two next to each other and adjacent plate strands form. These plate strands are pushed on the roller table in a station 2. There will be one the strands at the interface the starting plates sprayed from above with solvent. In other embodiments become both strands with solvent sprayed.

in the first described embodiment enter the output plates after the solvent application in a Station 3, in which the output panels erected on the roller table and pressed against each other become. At the same time there is a centering of the output plates to each other or a desired one Offset the output plates against each other.

In a station 4, the resulting new plates are stored or stacked.

In another embodiment not shown is a single Strand of successive output plates on a roller table or a conveyor belt and provided with solvent. The other output plates to be joined are manually or mechanically taken from a pile and onto the on the roller table or the Transport belt lying output plates positioned.

For the machine Handling the output panels is also a robot. Of the Robot can with a gripping tool and / or a Vakuumansaugung work. The vacuum suction is also at rough surface of the Starting plates possible, if the suction heads / surfaces are with a wide-area and apply soft / conformable / elastic gasket to the output plates.

The inventive compound the output plates can in another embodiment without roller table or conveyor belt by means of a robot by the robot first a processed according to the known method described above Starting plate from a stack takes, in front of a fixed nozzle or over a fixedly arranged roller moves and then with the side on the the solvent is on the stack or on the top plate in the stack presses. This creates a Connection of two output plates to a new plate. The new Plates can then be deposited by the robot on another pile. advantageously, For example, the robot can position the output plates as they are being connected on request either new plates with tongue and groove or new plates arise with stepped rabbet.

Optional can Also, two robots work together by making each robot one up described, processed starting plate from a stack. As you wish both robots for a solvent application working on its output plate become.

Optional receives but also only one of the two output plates to be connected Solvent application.

The Connection then takes place in that each robot has its output plate presses against the output plate of the other robot. After that it is planned that one of the robots releases its output plate and that the other robot puts the resulting new plate on a pile.

In another embodiment, a robot is used with a table together by a top plate described above deposited on the table and there is provided from a moving nozzle with the solvent order and then taken from the stack a second processed output plate and on with Solvent-applied plate is pressed.

advantageously, can the robots in further embodiments a surface treatment on a still-skin plate or foam strand make yourself. Then it is provided by the robots or the single robot e.g. a milling tool emotional. Alternatively, a cut to length, even with extrusion skin provided plate by means of a robot to a stationary Guided editing tool along become.

Several Robots can also work together in such a way that the one robot still with an extrusion skin provided output plate holds and the other robot that Editing tool leads. In the same way, the solvent can be applied become.

In another variant, only a robot is provided with a Table or a stationary chuck or other fixture, by the still provided with an extrusion skin output plate is held with the holding device while the robot with a Machining tool removed the extrusion skin, then with a nozzle or other tools the solvent applying and a connection to a second processed output plate causes.

Optional can Instead of a robot, two robots can be used. As other tools can Rollers, coating devices, also serve plates.

For the one-sided Machining an output plate, it is advantageous if the robot or the holding device at the same time a curvature of unilaterally processed Plate prevents. Therefore Are suction or holding devices with multiple suction heads, which the output plates on the edge and center so that bending forces in the middle Output plate occur, which compensate for the voltages that otherwise a curvature lead the output plates can.

The described robots are also beneficial because deal with them Easily compensate for thickness tolerances of prefabricated output plates to let.

To the Compensation of thickness tolerances can also be the table described above equipped in a special way be, e.g. by a yielding arrangement or a yielding one Education.

in the embodiment are two output plates with a contact side, a top and called a bottom. The two superimposed output plates are interconnected by connecting elements. It's lost two adjacent connecting elements inclined at 45 degrees to each other. With a plate thickness of 50 mm, the connecting elements have a length of 60 mm and a thickness of 35 mm. The connecting elements have the shape of long strips in the dimensions 60 mm × 35 mm × length of the plates to be joined.

In further embodiments is the Thickness of the output plates 40 or 60 mm, the thickness of the connecting elements 20 to 50 mm and the length the connecting elements 40 to 80 mm, the length of the connecting elements is equal to the plate length.

The Fasteners are made of the same material as the output plates made, XPS.

in the embodiment the fasteners are cut from 35 mm thick XPS panels. To cut is a saw In other embodiments, punching has been used or cutters used.

The belonging to the fasteners Recesses in the plates are produced with a disc milling cutter have the same radius as the fasteners at the bulge has, namely 30 mm.

With the side milling cutter can the recesses are incorporated extremely quickly. That is before everything for a processing of plates of advantage, on a roller table be moved continuously. Then it is envisaged that the milling machine itself a small piece moved with the plates. The faster the recesses arise, the lower the necessary range of motion of this working variant.

In another variant of the work, the plates are separated and for a short time Time for incorporation of the recesses recorded. The shorter the Processing time is, the better the work flow with the Plates.

at the mechanical connection of the plates over the entire length of the plate and width, the plates are continuously grooved inline in that the plates by means of a roller conveyor under a Milling machine through guided is, with the grooves milled become.

In the exemplary embodiment, the plates are formed by initially (over a certain period of time) continuously using two XPS strands produced two extruders and run after sufficient cooling over each other. These XPS strands initially have an extrusion skin on all sides. Before the strands come into contact with each other, the XPS strands on the contact surface are removed from the extrusion skin by milling.

Then come the XPS strands to each other to the plant. This prevents the weight of a bowl of bowls XPS strands. About that both strands become between two conveyors, in the embodiment two roller tracks, held. The upper rollers are adjustable and / or yielding arranged to account for thickness tolerances and format changes. Also the upper roller table counteracts the bowls.

in the embodiment the incorporation of the recesses and the subsequent insertion of the Connecting elements immediately after the XPS strands lie on top of each other. in the embodiment The fasteners are glued. This is a small one Amount of solvent sufficient, because the solvent by the pressure on insertion well distributed.

After the connection of the XPS strands These are edited on the sides and cut to length. This creates the Plates. The connecting elements are hardly recognizable in the resulting cut surface, because they are flush to lock and have the same structure as the plates.

to Incorporation of the recesses are provided disc milling cutters on movable slide can be held pivotally. The pivoting plane is located parallel to the milling plane. That the router occurs by pivoting in function. His activities are limited on a dip in the plastic foam and the subsequent return movement. While This process becomes the cutter on the carriage with the plates moved.

in the embodiment are each provided on a slide two side milling cutters, in the above Senses are arranged inclined. Both side milling cutters are in at the same time Function brought so that with each operation two next to each other and inclined mutually recesses arise.

In other embodiments will be more routers or just a router in action brought. The different cutters can have a common Drive coupled or even have only a common control.

On only cutter on one side of the plate can produce the differently inclined recesses, if its milling head still has another pivoting mobility.

The after cutting to length the XPS strands resulting panels have no fasteners on the cut surfaces. In another embodiment be in an additional Work step there set more fasteners.

Claims (16)

Method for connecting at least two starting plates of plastic foam to a new plate, in particular of alternative or HCFC-free driven plastic foam plates as starting plates to new plates with a minimum thickness of 70 mm, in particular also polystyrene foam plates, characterized in that a) starting plates are used, which are extrusion skinless at the contact surface and b) the connection of the starting plates takes place by means of solvent welding. Method according to claim 1, characterized by Use of organic solvents for source welding with a boiling point of less than 150 degrees Celsius for solvent welding. A method according to claim 1 or 2, characterized by the use of acetone as solvent. Method according to one of claims 1 to 3, characterized by solvent mixtures. Method according to claim 4, characterized by Use of a mixture with water. Method according to one of claims 1 to 5, characterized by spraying of the solvent or by the use of rollers or plates to imprint the Solvent. Method according to one of claims 1 to 6, characterized that output plates are used which match each other Welding surfaces plan or curved run, with the adjustment of the welding surfaces a) by mechanical Editing and / or b) by heat treatment and / or c) generated by pressure and / or bending of the corresponding other output plate surface becomes. Method according to one of claims 1 to 7, characterized that the plates to the with solvent partially dissolved Welding surfaces against each other depressed become. Method according to one of claims 1 to 8, characterized that extruded foam strands welded together so that a new strand is formed, which is cut to slabs. Method according to one of claims 1 to 9, characterized through a surface treatment of Starting plates by milling or planing or cutting or sawing. Method according to one of claims 1 to 10, characterized by a solvent application the output plates, a) wherein the output plates in two adjacent Rows one behind the other on a roller table or band, and marked by subsequent straightening the output plates and their compression or b) wherein the output plates in a row one behind the other on a Roller table or a conveyor belt or resting on a table and for each of the plates has a second plate taken from a stack and on the belonging lying plate pressed will or c) with an output plate taken from a stack and after the solvent application with the sticky side back on the stack and pressed and the resulting new plate is placed on a new stack or d) where simultaneously two starting plates from a stack or taken from two stacks and provided with a solvent application and be connected with each other. Method according to one of claims 1 to 11, characterized that a) Starting plates are used, their extrusion skin at both opposite Flat pages is removed or b) starting plates with extrusion skin be used, the extrusion skin removed on a flat side will or c) used starting plates in the form of two foam strands whose extrusion skin is removed on a flat side and followed by a solvent application be provided and interconnected and then cut to length or d) used starting plates in the form of a foam strand whose extrusion skin is removed on a flat side and then provided there with a solvent order and connected to prepared other plates. Method according to claim 12, characterized in that that held starting plates when removing a foam skin and protected against curvature. Method according to one of claims 1 to 13, characterized by the use of stationary solvent application devices and / or stationary surface treatment tools when using a robot for the plate movement. Method according to one of claims 1 to 14, characterized through the use of output plates, which lie with lying plastic foam plate at the top and the bottom have a foaming skin and at the Contact surface surface-treated are. Method according to one of claims 1 to 15, characterized through the use of foam sheets made of polystyrene, polyethylene, Polypropylene, ethylene, propylene copolymers.