DE2239204A1 - LAMINATE AS WELL AS METHOD AND DEVICE FOR ITS MANUFACTURING - Google Patents

Description

u.z .: H o73 M (My / Schm / Lo)

Spa. LAVORAZIONE MATERIE PLASTICHE L.M.P.-Turin / Italy

"Laminate as / ie method and device for its production"

Priority: Aug 10, 1971; Italy;

Registration number: 69687-A / 71

The invention relates to a laminate and a method for producing this laminate from foamed webs thermoplastic synthetic resins (foams) and flexible covering sheets or support sheets (e.g. paper, cardboard, textile, Aluminum foil, plastic foils) and a device for implementation of the procedure.

This branch of technology is becoming increasingly important because of the combination of the two used It is possible to give the laminate a number of properties that are inherent in fabrics

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different areas of application are urgently needed (mechanical resistance, thermal and acoustic insulation, water tightness USWo) ο

The difficulties that have not yet been satisfactorily resolved include the greatest possible adhesion of the support film or support web to the foam web, the lowest possible weight in view of the necessary mechanical resistance, the immutability of the dimensions over time, as well as ease and economic efficiency in processing . If, for example, special adhesives are used to produce the laminate, it is easily possible _{/ to} achieve good adhesion between the support sheet and the foam sheet, but the lightness of the laminate and the economy of production are certainly impaired at the same time.

With the method ^{according to the invention, 1} should therefore be counteracted as best as possible all of the above-mentioned difficulties.

According to the invention there is provided a method of making a laminate formed from a sheet of solid Foam is made of a thermoplastic resin with closed cells attached to at least one of its surfaces with

or Eelag foil or Relag membrane a support film or support sheet / is provided. The procedure is characterized in that the foam sheet and the Support sheet by being stapled directly to one another

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be united by previously in the support track a functional Amount of heat "at a temperature above the melting temperature des thermal, oplas tic synthetic resins and stored then the support track continuously in pressure contact with the foam to ff "bahn" is brought, with the cells of the Foam sheet in stiff emi state are to be melted by at the. Surface of the foam web as a result of the in the support web accumulated Yfärme the two tracks progressing to the To be adhered together without the use of an additional adhesive or adhesive device.

A special aspect of the method according to Invention is therefore that the foam web in Moment of attachment to the support sheet Ambient temperature (or in any case a lower temperature than the softening temperature) and is therefore stiff or rigid. Under these circumstances, the foam sheet can move without relatively high pressures to produce the collapse

she
Withstand connection as / to create the necessary strong

and uniform adhesion between the foaming web and the ' Support track are desirable. Hur a thin surface layer (approx. 0.05 mm to 0.5 mm) of the foam-off web is through the Contact with the support sheet melted, while the remaining thickness of the foam cover remains rigid and undeformed.

It is beneficial to run the process under continuous Feeding the foam sheet and the support sheet from theirs respective supply rolls to a coating zone

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to lead. In a typical embodiment, there is the Foam sheet made of expanded polystyrene with closed Cells and has, for example, a diameter of 1 to 10 mm,

FlMchcn-

While the support sheet is made of Kraft paper with a weight of

2 2

for example 100 g / m to 150 g / m.

According to a feature of the invention, the Schäumstoff ~ is ground before coating by heating to a temperature 10 ⁰ C to 30 ° C below the softening temperature

on-

of the foam] ioft / foamed, with two effects being achieved at the same time, namely, firstly, because of the use of a foam with closed cells, an increase in the thickness of the foam sheet as a result of the expansion of the gas in the cells at the said temperature. In the case of polystyrene foam, the foam web can be heated to 100 ° C to 120 ° C, for example. The second effect consists in "tempering" the display sheet, ie in eliminating the internal stresses generated in the foam by the manufacturing process with the aim of imparting the desired shape stability to the laminate. As soon as the thickness of the Sch.nuraatof.C-bahn has reached a suitable level by heating, this increased thickness is stopped or blocked by rapid cooling, typically to at least 50 ° C., for example with the aid of currents of cold air, so that the cells of the Foam definitely become stiff or rigid again before the foam sheet is connected to the support sheet to form a laminate.

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ILO

Foam webs, including polystyrene, are typically made by extrusion of a heat-softened, pressurized ϊ, ϊε &: θ from polystyrene in which a normal gaseous blowing agent, for example isopentane, is dissolved or dispersed. The decompression of the hot mass at the exit from the extrusion gap causes the propellant to expand and as a result foam cells are formed. The cell structure is blocked by appropriate cooling of the extruded web, and the web is preferably stretched in the transverse and longitudinal directions before cooling or during cooling in order to reduce its density. The foam webs obtained in this way η v / earths preferred for the method according to the invention. According to the invention, however, a foam sheet produced in the manner described above is preferably subjected to pressure stabilization of the cells before it is subjected to the above-described preheating stage. The reason for this is that the gas pressure in the foam cells as a result of cooling after the explosion -. traditionally is reduced to subatmospheric pressure so that subsequent immediate heating of the foams of fbalin produces little or no increase in the thickness of the web, d _o ho that it does not decrease the density of the foam in a desirable manner. According to the invention, a foam web obtained in the manner described above is stored for at least 24 hours at atmospheric or slightly above atmospheric pressure (e.g. 1.1 ata). Under these conditions, atmospheric air diffuses into the foam cells to an extent that is sufficient to get in the cells

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ORlGtNAL

atmospheric pressure (or slightly above atmospheric pressure) au generate with the result that "on subsequent heating the foam fit ο ff b »hn because of a strong thermal expansion pressure of the locked gas was actually a "considerable increase the thickness of the foam web is achieved.

An important feature of the invention relates to the coating zone. In particular, in a continuous process sequence, the foam web is advantageously from a roll with a large diameter unwound and between two pressure plates or pressure rollers together with the support sheet passed through, which is unwound from a supply roll and passes through a preheating zone in which the temperature of the Support sheet increased to above the melting point of the synthetic resin of the foam sheet. The difficulty is to effectively utilize the heat accumulated in the support sheet to adhere instead of any additional heat that the foam web through the support web, for example from the Pressure roller (coating roller) is supplied, and that is why because both the extent and effects of such additional heat are difficult to control. At the same time, it is natural desirable to establish the connection (melting a surface layer of the foam web) if possible the utilize all of the effective heat accumulated in the support sheet. As a result, according to the invention, the foam sheet and the preheated support web is connected to one another under mechanically applied pressure by V / arms, whereby simultaneously care has been taken to ensure that the heat dissipation from

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the surface of the support web opposite the contact surface is at least partially blocked into The melting point of the synthetic resin of the foam web exceeds, and the pressure contact between the foam web and the support web is continued beyond the convergence area or is repeated in that the support web with the aid of at least one pressure-applying and one which does not exceed the softening point of the synthetic resin of the foam web :. Temperature heated surface is pressed against the foam web, while the surface of the foam web in contact with the support web is in a sticky state. In a practical embodiment, the foam web and the support web can converge in a nip between a heated roller supporting the foam web and a heated roller pressing the support web against the foam web, the heated roller having the preheating temperature mentioned and the linear speed of the laminate in the roller nip at least 3 m / min is «, Under these conditions, practically no additional heat is transferred from the heated roller through the support sheet in the roller gap to the foam sheet sticks _o During the time during which the contact surface of the foam sheet is sticky plastic

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Condition, the pressure contact is not stretched as a result, ö.oii the laminate is passed between at least one further pair of printing rollers or printing plates, in which the support sheet is countered by a roller or plate heated to a temperature below the melting point of the synthetic resin, preferably below the softening point of the synthetic resin In this way, undesired heat emission from the exposed surface of the support sheet is effectively prevented, while at the same time no additional amount of heat is transmitted to the foam sheet which could soften the foam sheet. Another embodiment of a device for preventing the emission of heat is described further below.

When using polystyrene foam, the Support sheet fed to the coating zone at 160 C to 100 C, typically be preheated to about 170 C, the for the fabric used and its thickness so selected are that the substance can accumulate the necessary amount of heat. At-

Area- ₂

For example, a paper web with a weight γοη 100 g / in to 150 g / m is suitable in all cases. Flat material made of metal, for example aluminum foil, webs of textile materials and webs of plastics with a sufficiently high melting point can also be used. Both surfaces of the foam balm are preferably coated with a support sheet,

The invention is explained below with advantageous details based on schematic drawings of an execution ^ -

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example explained in more detail. It shows:

Fig. 1 is a schematic side view of an implementation a device suitable for the method according to the invention j

I ¹ Xg ₀ 2 a section through a detail of the device :; . ■ '-: _ ■'':

Pigc 3 a section through another detail of the Contraption. .

A sheet 12 of expanded polystyrene in one width of 'for example I40 cm is wound on a roll TO, In one embodiment of the method, the web 12 preferably obtained by the following process steps:

a) A polystyrene melt permeated by isopentane extruded under pressure through an annular gap and results a slack-shaped, foamed extrusion product;

b) a length of the smart extrusion in the proximity of the extrusion gap is reduced to a 3 "to 10 times (preferably 5 times) larger diameter than the original inflated or otherwise expanded and under diameter a draw ratio of 2: 1 "to 6: 1, preferably 4: 1 during des A'bkühleno stretched lengthways to room temperature;

c) that obtained in this way in the longitudinal and transverse directions Stretched extruded product is continuously slit open along a generatrix to a flat shape

. d)

and wound up relatively loosely on a flat; according to the wound foam obtained in process step c) bahn is {under atmospheric conditions for at least 24 hours

3 0 9 8 11/09 86

SAD

Pressure stored,

The Balm 12 is of the Ro3.1e 10 by the action of two parallel pairs of driver chains 141 16 unwound, those on the opposite longitudinal edge areas of the Act on the web. As can be seen from Fig. 2, each chain link the driver 14, 16 has at least one tooth 18, which in the web 12 penetrates, so that these in the aforementioned Randbexeichen is reliably detected by the respective driver chain pair, whereby the width and length of the track are kept constant v / earth. At the same time, the web 12 of heat radiating bodies 20, which are directed against the opposite surfaces of the web and are arranged between the pairs of entrainment grooves, heated to at least 100 C, whereby the thickness of the web increases, while their density decreases accordingly for the reasons already mentioned above. At the exit of the Mitneimerketten the runs Web 12 passes between groups of fans 21 for rapid cooling and then meets two trimming knives, one of which one 22 is shown in Fig. 1, and die'die web already Cut to the required width (e.g. 130 cm) before coating. The cut-off material 24 obtained in this way is therefore paper-free and can consequently be remelted be used.

During its entire remaining movement, the web 12 is carried along by a pair of rollers 26. The V / alsen are

covered with rubber. ·

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INSPECTED

From two gate rolls. Kraft paper 28 and 30 ', a paper spell 32 or 34 becomes the corresponding surface of the
Polystyrene foam web 12 out. Each of the two paper webs, which are 130 cm wide, runs over a ge ~

or shield
curved screen / 36 or 38 made of sheet metal, which is heated by electrical resistors 40 arranged inside the screen to 170 ° C., for example. The two screens converge to the foam web 12 and run in a '.Dangente in the direction of movement of the foam web and end in pressure feet 36A, 38A (see Pig «3)» which are arranged facing each other. The pressure feet are flat and extend parallel to the
Foam web 12, and the two screens 36, 38 are in
Direction to the web 1 2 adjustable and form a coating sz one L, in which the preheated to 170 ° C paper webs 32, 34 of the pressure feet against the surfaces of the
Foam web 12 are pressed, which is about ambient temperature. Because of this last-mentioned temperature, the cell membranes of the foam web 12 are relatively rigid,
which makes it possible to take the coating under proportionately
Apply strong pressure and ensure that the
To achieve paper webs on the foam web without permanently deforming the cell structure of the foam web. Typi-Bcherweiee press the pressure feet 36A, 38A, the foam web 12 together by no more than about 25 $ of its thickness.

In the coating zone L, each paper web 32 ₉ 34 produces a surface melting of the foamed material web 12, and therefrom

the result is a mutual arrest ”, the one visible in FIG. 3

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last Y / ideratandspaar 40 is go arranged en the Schinne 36, 38 in an area just before the Beochichtungszone L to 170 ° C erv / ärmt _o In this arrangement the Scliaumstoffbalm 12 strikes the paper Dunning that the preheating temperature of 170 ° C have, and at the same time the pressure feet are held relatively v / poor solely because they form an extension of the corresponding screen 36 or ". If necessary, the inflow of heat into the pressure feet can be reduced by providing a heat-insulating insert (not shown here) between each pressure foot and the corresponding screen at a point immediately behind the area of the confluence L ^f , or the pressure feet can be cooled by air currents are blown transversely through them, whereby their temperature is lowered to the desired level (advantageously between 80 ° C and 40 ° C, assuming that the softening point of the polystyrene foam is about 100 to 110 C) «In the in In the arrangement shown in FIG. 3, the temperature of the pressure feet gradually falls in the direction of movement of the laminate, similar to the way in which the temperature of the paper webs decreases due to their contact with the relatively cool foam-off web 12. In the arrangement shown in FIG. 3, it can be assumed that a length, for example the length M of each pressure foot ei ne has a temperature below the melting point of the synthetic resin forming the foam sheet, while a subsequent length N has a temperature below the softening point of this synthetic resin. In this way, the pressure feet extend the pressure contact

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flAD ORIGINAL.

the paper webs and the foaming material web and prevent at the same time, any significant heat dissipation from the exposed ones Surfaces of the paper webs without feeding the foam web so much that the foam is softened could. In a laminate obtained in this way, the bond is so strong that the paper webs foam off off bahn without tearing or tearing off cannot be separated can. '-

It is obvious that the tasks of the screens 36 " also, can be met by one or more pairs of heating rollers, the last pair of which is arranged to be forms a Y / alzenspalt, which represents 'the converging I L', and to the at least one other pair immediately moderately heated rollers which act as a pressure pad 36A, 38A to expand the contact pressure and increase the heat Take over the shielding device.

The length of the coating zone L in the direction of movement is a puncture of the temperature drop in. the paper webs in Connection to the contact with the foam web 12 or des Melting on the surface of the foam web. That means, that the puncture of the pressure feet stops as soon as the melted layer has hardened again. Of course, this corresponds to a ge ~ know range of movement of the laminate. Polly it is unnecessary to make the pressure feet longer than necessary. As the speed of movement can vary within wide limits (typically from 3 m / min to 6 m / min and more), the

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Length of the coating zone-L as a time unit of at least one second "to a maximum of about 5 seconds η ο

Aiii the output of the coating sz one L is a pair of rollers

42 arranged. These rollers can be heated and form one

or precisely dimensioned
calibrated / passage, the gap height of which is less than the thickness of the laminate 12A leaving the coating zone L, in order to temper the connection between the laminate elements 12, 32-3.4 · The laminate calendered in this way can be heated by infrared radiators 44, to initiate further foaming of the foam web 12 and a resulting increase in the thickness of the foam web, the laminate 12A being held stretched by the tensile force exerted by the above-mentioned rollers 26. It is obvious that one with said further foaming one The laminate re-foamed in this way is then passed between a pair of rollers 46. These rollers are strongly cooled on the inside by water which is fed through connecting pipes 48. This strengthens the adhesion of the laminate elements.

Calibration on the

With a / v / roller pair 50 the laminate / end desired strength is brought.
cTältigo / β Each of the Y / al rolls of this pair of rolls is a

sized fan 52 for final cooling of the exact / laminate assigned. Finally, the laminate is cut with the aid of a cutting device 54 located behind the fans in

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Sheets cut to the desired length

- Expectations -

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Claims (15)

Λ η S ρ r ü c h e 1. Laminate comprising a rigid foam made of thermoplastic synthetic resin with closed cells and a covering layer applied to at least one flat side of the foam, characterized in that
Foam (12) and covering layer (36,38) are sealed without adhesive. 2. A method of making a laminate from a sheet of rigid thermoplastic resin foam
with closed cells, which is provided with a covering film or covering sheet on at least one of their surfaces, thereby
characterized in that the foam sheet and the covering sheet are connected to one another by adhesion by first in the
Covering sheet an appropriate amount of heat is stored at a temperature above the melting temperature of the thermoplastic synthetic resin, that then the covering sheet with the foam sheet
is continuously brought into pressure contact when the foam is stiff, and that the two webs are fed to a coating zone in which the two webs pass
Melting of the surface area of the foam sheet as a result
of the heat accumulated in the covering sheet progressively with each other without the use of an additional adhesive or any
Gluing device are connected. 3. The method according to claim 2, characterized in that 309811/0986 the thickness of the foam sheet is increased beforehand by heating the foam bean to a temperature around 10 ° C to 30 ° C is lower than the softening temperature of the synthetic resin, and that the thus increased thickness is blocked by cooling. 4. The method according to claim 3, characterized in that the foam web during heating along its opposite Longitudinal ridges are detected, and that they after cooling and before coating with the covering sheet along these edges is cropped. 5. The method according to any one of claims 2 to 4, characterized characterized in that the pressure contact for producing the laminate between the covering sheet and the foam sheet takes place while .the heat dissipation from the contact surface facing away from the surface of the facing is essentially prevented. 6. The method according to any one of claims 2 to 5, characterized in that that the foam sheet is further foamed by heat after connecting to the covering sheet. 7. The method according to any one of claims 2 to 6, characterized in that that the foam sheet used to produce the laminate is a polystyrene foam sheet in a thickness of 1 mm to Io mm. 8. The method according to any one of claims 3 to 7, characterized in that that the heating of the foam sheet at a temperature 309811/0986 _ßAD temperature of 100 ° C to 12o ° C. 9. The method according to claim 7, characterized in that the temperature of the Schaumstoffbahη immediately before contact with the covering sheet is less than 50 ° C. 10. The method according to any one of claims 2 to 9, characterized in that that the covering sheet is made of kraft paper. 11. The method according to any one of claims 2 to 10, characterized in that dats the two surfaces of the foam web each coated with a covering sheet. 12. The method according to claim 5, characterized in that the foam sheet and the covering sheet in a convergence area be brought together, through which the two tracks are guided, while the covering sheet has its preheating temperature, which exceeds the melting point of the synthetic resin, whereupon the pressure contact between the foam sheet and the covering sheet beyond this convergence area expanded or thereby repeated is that the covering sheet with at least one pressure-applying surface, which is on a below the melting point of the synthetic resin lying, preferably the calibration point of the same not reached temperature is heated against the foam sheet is pressed while the surface of the foam sheet in contact with the covering sheet is still sticky. 13. The method according to claim 12, characterized in that 309811/0986 the laminate of the foam sheet and the covering web bed at a linear velocity of at least 3 m / min, and in that the length of the coating zone, which has the confluence area and the pressure-applying surface, a movement time of 1 to 5 seconds corresponds, 14, method according to claim 3, characterized in that in a preparatory stage an extruded sheet of the foam " atmospheric or super-atmospheric for at least 24 hours Pressure is applied, and that only then is the thickness of the web increased by heating. 15. Device for carrying out the method according to one of the Claims 2 to 14 / characterized by an inlet guide oriented obliquely to the running direction of the foam web (12) (36,38) for the at least one covering sheet (32,34), as well as through a heating device (4o) for the covering path running on the inlet guide. 30 9811 / 098R OFHQtNAL INSPECTED