US3032815A

US3032815A - Process and apparatus for manufacturing sheets from polymerizable substantially solvent-free casting resins

Info

Publication number: US3032815A
Application number: US677090A
Authority: US
Inventors: Gerber Karl Heinz
Original assignee: Braunschweiger Farbenwerke Wilhelm Pieper and Co
Current assignee: Braunschweiger Farbenwerke Wilhelm Pieper and Co
Priority date: 1956-08-14
Filing date: 1957-08-08
Publication date: 1962-05-08
Anticipated expiration: 1979-05-08

Description

y 8, 1962 K. H. GERBER 3,032,815

PROCESS AND APPARATUS FOR MANUFACTURING SHEETS FROM POLYMERIZABLE SUBSTANTIALLY SOLVENT-FREE CASTING RESINS Filed Aug. 8, 1957 8 Sheets-Sheet 1 INVIJNTOR.

HTTOR N E .l

y 1962 K. H. GERBER 3,032,815

PROCESS AND APPARATUS FOR MANUFACTURING SHEETS FROM POLYMERIZABLE SUBSTANTIALLY SOLVENT-FREE CASTING RESINS Filed Aug. 8, 1957 8 Sheets-Sheet 2 "n H "'l.

FIGQZ HTT'ORNEf/ May 8, 1962 K. H. GERBER 3,032,815

PROCESS AND APPARATUS FOR MANUFACTURING SHEETS FROM POLYMERIZABLE SUBSTANTIALLY SOLVENT-FREE CASTING RESINS 8 Sheets-Sheet 3 Filed Aug. 8, 1957 ,l lllv v l ll ll l l INVENTOR.

BY mt .lfiqw firm/way May 8, 1962 K. H GERBER 3,032,815

- PROCESS AND APPARATUS FOR MANUFACTURING SHEETS FROM POLYMERIZABLE SUBSTANTIALLY SOLVENT-FREE CASTING RESINS 8 Sheets-Sheet 4 Filed Aug. 8, 1957 INVENTOR.

hw 0 I mm N MMMWLWMMY A QN RN ow Q- in wN KML ' HTTORNEy May 8, 1962 K. H. GERBER 3,032,815

PROCESS AND APPARATUS FOR MANUFACTURING SHEETS FROM POLYMERIZABLE SUBSTANTIALLY SOLVENT-FREE CASTING RESINS 8 Sheets-Sheet 5 Filed Aug. 8, 1957 M- MW Mam INVENTOR.

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s O m 0 mwmmwmmflmw May 8, 1962 K. H. GERBER 3,03 5

PROCESS AND APPARATUS FOR MANUFACTURING SHEETS FROM POLYMERIZABLE SUBSTANTIALLY SOLVENT-FREE CASTING RESINS Filed Aug. 8, 1957 8 Sheets-Sheet 6 XML BY Mal HTTORNEQ/ May 8, 1962 K. H. GERBER 3,032,815

PROCESS AND APPARATUS FOR MANUFACTURING SHEETS FROM POLYMERIZABLE SUBSTANTIALLY SOLVENT-FREE CASTING RESINS 8 Sheets-Sheet 7 Filed Aug. 8, 1957 |NV ENTOR ATTORNEY y 1962 K. H. GERBER 3,032,815

PROCESS AND APPARATUS FOR MANUFACTURIN EETS FROM POLYMERIZABLE SUBSTANTIALL SOLVENT-FREE CASTING RESINS Filed Aug. 8, 1957 8 Sheets-Sheet 8 HTTORNE 5/ United States Patent The present invention relates to a process and apparatus for manufacturing sheets from polymerizable, substantially solvent-free, casting resins.

For some time now plastic sheets have been manufactured continuously in endless bands. For example, a solution of the plastic materialtogether with the addition of stabilizers and softeners in some cases is applied to a rotating evaporation drum and within the period of time required for almost one revolution the solvent is evaporated and the plastic is hardened to such a degree that it can be removed from the rotating drum and after sufficient ripening can be stored away. During the manufacture of such sheets no change takes place chemically in the plastic material. In particular there is no molecular expansion during the manufacture of the sheet so that the plastic material of the sheet has the same solubility characteristics after the sheet is manufactured as the material had before it was made into a sheet.

Although sheets may be manufactured quickly and efiiciently in this manner there are several undesirable limitations in this process of manufacture. Thus, the

requirement that the solvent evaporate to a very great extent during the relatively short time of less than one revolution of the drum limits the use of the above process to extremely thin sheets since otherwise the extent of evaporation of the solvent is not sufiicient. Although sheets obtained in this manner are qualitatively equal to many purposes and even ideal for some purposes, the sheets obtained in this way are not satisfactory where there is a requirement of resistance to dissolving, to softeners, to dyes, and to high temperature, and where there is a requirement of mechanical resistance to such actions as bending, pressure, cutting, frictional rubbing, etc.

Qualitatively the latter requirements are met by plastic plates which are manufactured under heat and pressure in multi-layer presses with the use of paper impregnated with urea or melamine resins.

In such presses the resins are chemically changed into plastics which for practical purposes cannot be dissolved or melted, i.e. thermosetting resins, and which have a high molecular weight. Also these materials are exceedingly strong mechanically. In manufacturing such plates it is possible to continuously carry out the impregnation of the paper strips, but the pressing must be intermittently carried out.

One of the objects of the present invention is to provide plastic sheets having all of the above desirable properties (resisting dissolving and melting, i.e. properties of thermosetting resins) but made continuously in a very quick and efiicient manner so that the disadvantages resulting from the non-continuous operation necessitated by the multi-layer press are avoided.

Another object of the present invention is to manu-' facture such plastic sheets together with other sheets to which the plastic sheets are joined, these other sheets being sheets of wood, fleece, woven fabric, etc.

A further object of the present invention is to use for the manufacture of sheets according to the present in-v vention devices which will guarantee proper application of the material to treating surfaces and the like, such devices guaranteeing uniform thickness of a layer of sheet material as well as eflicient distribution thereof, etc.

An additional object of the present invention is to provide a process and apparatus capable of manufacturing sheets of the above type in double thicknesses, for example, and a process and apparatus capable of forming from a pair of such sheets elongated tubes which may be hollow or which may have any desired bodies located therein.

With the above objects in view the present invention mainly consists of a process of manufacturing an article composed at least in part of a sheet formed from a polyrnerizable, substantially solvent-free casting resin, this process including the steps of depositing a layer of flowable material composed of the casting resin and an additional component which reduces the hardening time thereof on a treating surface on which the deposited material hardens in a relatively short time, then continuously removing from the treating surface the layer of material deposited thereon, the material being continuously removed in the form of a continuous sheet, and the thus-obtained sheet is then further treated.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, to-

one possible process and apparatus according to the presout invention;

FIG. 2 is a diagrammatic illustration of another process and apparatus according to the present invention, the process illustrated in FIG. 2 being carried out in a controlled atmosphere;

FIG. 3 illustrates a further process and apparatus according to the present invention;

FIG. 4 shows still another process and apparatus ac-- sheets of wood, for example;

FIG. 5 shows a process and apparatus capable of making a double thickness of sheets according to the present invention;

FIG. 6 illustrates a particular apparatus used according to the present invention for manufacturing sheets and joining the same to other sheets;

FIG. 7 is a transverse sectional view taken along line 7-7 of FIG. 6 in the direction of the arrows and show-' ing in particular the cross section of a belt or endless band according to the present invention;

FIG. 8 is a partly diagrammatic, fragmentary, partly sectional illustration of a particular combination of devices used for manufacturing a sheet according to the present invention;

FIG. 9 diagrammatically illustrates a process and apparatus which are used in accordance with the present invention to provide a sheet having a desired pattern there- FIG. 10 diagrammatically illustrates a process and apparatus for manufacturing tubes from a pair of sheets according to the present invention;

FIG. 11 illustrates in cross section a finished tube with an elongated body located therein;

FIG. 12 shows a tube which is hollow;

FIG. 13 is a fragmentary transverse view of one possible apparatus according to the present invention for v smoothing and eliminating bubbles from a layer of material used to form a sheet according to the present invention; and

FIG. 14 is a sectional illustration fragmentarily showing another embodiment of a structure for smoothing and eliminating air bubbles from materials used to form a sheet according to the present invention.

For a few years now the so-called casting resins have been available, and such resins have the property of being able to be placed in a desired shape without the use of pressureas a more or less cohesive liquid. Furthermore these resins either contain no solvents or if they do contain a solvent the latter solvent such. as, for example, styrol, becomes converted under certain conditions with the dissolved material into hard polymerized bodies at temperatures which are so far below the boiling point of the solvent that practically no loss of solvent occurs through evaporation, and moreover these resins have mechanical and other properties in such a wide range that they can be adapted to a large variety of purposes, providing variations between elastic and hard materials, and by having combined with the resins such additions as dyes,.pigments, fillers, materials for providing protection against light, materials for increasing resistance to heat, developers, softeners, fibers, etc.

The so-called unsaturated polyester resins are an example of such casting resins, and these polyester resins are essentially composed of eventually modified polyesters of tap-unsaturated dicarboxylic acids mixed with liquid substances in the reactive group CH =C These and similar casting resins can be used in the manufacture of sheets by being placed upon highly polished flat surfaces and then before or after the material hardens it can be joined with a carrier sheet such as a sheet of plywood or the like using a layer of adhesive, or after hardening the sheet is simply withdrawn from the negative plate so as to be available for further treatment.

The present invention takes advantage of the fact that it is possible to influence to a very large extent the hardening time of such casting resins by the addition thereto of suitable catalysts and by mixing together suitable types while heating the same through a relatively low minimum temperature. In accordance with the present invention the time required for hardening of the casting resins is so greatly reduced by the use of such additions with the resins that the resins can be used in a continuous process for making sheets such as that which heretofore has been suitable only for the manufacture of extremely thin sheets. After a sheet is formed according to the present invention it is further treated as by being joined with other objects such as other sheets, also in accordance with the present invention.

For the process of the present invention all casting resins may be used which are fiowable, which harden at an infinitely slow rate at room temperature, which harden very quickly at high temperatures, and which do not lose any considerable amount of volatile components during polymerization. The following partially polymerized materials are examples of materials having the required properties, these materials being used in a condition where they are not fully polymerized: unsaturated polyesters, ethoxylene casting resins, and phenol casting resins such as phenol formaldehyde. As catalysts which will reduce the hardening time of the casting resins the following materials are suitable: organic peroxides such as benzoyl peroxide, cumene hydroperoxide, cyclohexanone peroxide, lauryl peroxide, methylethylketone peroxide; also organic amines such as ethylene-diamine, ethylene-triamine, and dipropylene-triamine; furthermore certain inorganic acids such as hydrochloric acid, phosphoric acid, and sulfuric acid; and organic acids such as for example p-toluene sulfonic acid as well as acid salts such as ammonium chloride and ammonium nitrate.

Referring now to FIG. 1 there is illustrated therein a hollow rotatable drum 1 whose outer surface forms a treating surface used for treating material according to the present invention, this drum being rotated about its axis 2. The drum is driven so that its speed of rotation can be continuously regulated. An unillustrated heating means is located in the interior of the drum. A means 3 is provided for directing a stream of material 3a against the outer treating surface of the drum 1, and this means 3 is in the illustrated example a suitable spray nozzle while the material 3a is in the form of a powder or liquid which prevents sticking of the casting resin against the outer treating surface of the rotating drum 1. A means 4 is provided for directing a stream of flowable casting resin together with a material for reducing the hardening time thereof onto the treating surface 1 and the material composed of the casting resin and the catalyst for reducing the hardening time thereof is indicated at 12 both in the form of the stream which is provided by the means 4 illustrated as taking the form of a nozzle as Well as the layer of material 12 deposited on the treating surface of the drum 1.

In order to prevent the material 12' from sticking to the treating surface any of the following materials may be sprayed by the nozzle 3 onto the surface of the drum: paraffin dissolved in benzene or paraffin hydrocarbons, or silicone oils dissolved in benzene hydrocarbons; also, gelatin dissolved in water, or bone glue dissolved in water, and polyvinyl alcohol dissolved in water or ethyl alcohol.

Suitable rollers 1.4a and pressure rollers 14 are provided so as to guide a bendable plate 15 to the main drum 1 so that the plate 15 passes the main drum 1 and in so doing becomes joined with the sheet 12' before the outer surface thereof is hardened. The drum 1 rotates in the direction of arrow 11 and the nozzles 3 and 4 are supported in such a way that they can be adjustably shifted through a predetermined angle so as to have their positions with respect to the axis of rotation of the drum I adjusted so that the angular distance 041 and the angular distance (x can be regulated, the latter distance being the angular distance between the last pressure roller 14 and the nozzle 3 while the former angular distance a is the distance between the nozzles 3 and 4 angularly about the axis of rotation of the drum 1. By adjusting the positions of these nozzles it is possible to adjust the ratio between the available working time with respect to the material emanating from nozzle 4, i.e., the time during which the material remains in workable, not completely hardened, condition, and the time for spraying materials from the nozzles 3 and 4. The absolute amount of working time is controlled by the speed of rotation of the drum 1. The fiowable material composed of the casting resin and the additional component which reduces the hardening time thereof is deposited by the nozzle 4 on the rotating outer surface of the drum 1 continuously, and as the drum 1 turns in the direction of arrow 11 of FIG. 1 the flowable material deposited on the treating surface hardens and is completely hardened by the time it becomes located at the angular position of the rightmost pressure roll 14 of FIG. 1. The outer surface of the layer of material 12 is still soft enough so that this layer be comes joined with the sheet 15 of plywood or the like, for example, as the latter moves along the rolls 14a and 14 in the manner illustrated in FIG. 1. It will be noted that the hardened sheet 12 is continuously moved from the treating surface of the drum 1 while being continuously joined and advanced together with the additional sheet 15..

In FIG. 2 the elements indicated with

reference characters

1, 2, 6, 3a, 4, 11 and 12 are the same as those described above and illustrated with the same characters in FIG. 1. Also, the angles a and a correspond to those of FIG. 1. However, it will be noted that in the em bodiment of FIG. 2 there are no series of guiding and pressure rolls 14a and 14 and instead there is a single roll 13 which is placed in the position of the last pressure roll 14 of FIG. 1 and which serves to remove the hardened sheet .12 continuously from the rotating treating surface of the drum'li. The angle at indicated in FIG, 2 thus represents the angle available for polymerization and together with the speed of rotation controls the degree of polymerization that will be obtained. The polymerizing drum 1 as well as the removing roll 13 and the nozzles 3 and 4 are housed within a container 1a which is closed off from the outer atmosphere except for the opening at the bottom wall of the container through which the sheet 12 moves, as indicated in FIG. 2. In the particular example shown in FIG. 2 the material is sprayed through the nozzles 3 and 4 with the use of gases under pressure which are inert to the reaction taking place so that they do not produce any undesirable influence on the operation. These gases under pressure which are used for providing the streams or sprays of material 3a and 12 fill the container 1a and maintain in the latter a pressure greater than atmospheric pressure and these gases escape through the bottom wall opening through which the sheet 12 moves so that this opening for the sheet 12 as well as openings for the bearings of the shaft 2 of the drum 1 and the like need not be provided with any particular sealing structures. After the sheet 12 moves out of the container 1a it travels past a nozzle 18 which directs to one of the faces of the sheet 12 a layer of a suitable adhesive, and then the sheet 12 arrives at the pressure or squeezing rollers 16 indicated in FIG. 2. A suitable conveyor belt indicated diagrammatically by the arrow 21) in FIG. 2 serves to move a series of flat plates 17 such as plywood plates, for example, to the right, as viewed in FIG. 2, and these plates 17 become joined with the sheet 12 due to the layer of adhesive on the latter as well as the pressure applied between the rollers 16 and the conveyor belt carrying the plates 17, and in this way additional sheets are joined to the sheet 12 as the latter leaves the treating surface. In the event that a binary adhesive is used then the upper faces of the sheets or plates 17, as viewed in FIG. 2, may be provided with a layer of the second component of the adhesive, this layer being applied by the nozzle 19 indicated in FIG. 2.

In FIG. 3 also those elements indicated with the

reference characters

1, 2, 3, 3a, 4, 11 and 12 indicate the same elements which are indicated with these reference characters in FIGS. 1 and 2, and also the angles a and a are the same as those of FIG. 2. In FIG. 3 a removing roll 13 is provided rather than a series of rolls 14 as in FIG. 1. The angle 01;; indicated in FIG. 3 represents the time or angle available before applying to the outer surface of the partially polymerized layer 12 a web of Woven fabric 6 derived from a roll of this fabric 5. With suitable relatively simple supports it is possible to adjust the angles :1 a and on; so that they have any desired sizes. The pressure roll 7 serves to apply to the outer face of the web 6 another layer of a plastic material of the same properties as the layer 12', and this other layer is supplied to the roll 7 by the rolls 8 and 9 in the manner indicated diagrammatically in FIG. 3. Thus, the web 6 becomes located between the pair of

plastic sheets

10 and 12 which are joined to each other and which are fully hardened when they leave the treating surface 1 at the roll 13.

In the embodiment of the invention which is illustrated in FIG. 4 the treating surface instead of taking the form of the outer cylindrical surface of a rotating drum takes the form of the outer surface of an endless band. Thus, it is the outer surface of the endless band 23 which formsthe treating surface with the embodiment of FIG. 4. This band 23 is carried and moved by the pulleys or rolls 21 and 22 which are driven at the same rates of speed and in the directions indicated by the arrows in FIG. 4. The endless band 23 need not be made of a single piece of material and instead can be made up of a plurality of individual panels which are linked together and which can be used when it is desired to make individual plates rather than a long continuous sheet. Of course, such plates are simply small sheets. Of course, where such interconnected panels are used the

rolls

21 and 22 will not have a cylindrical configuration and instead will have a polygon-a1 cross sectional configuration corresponding to the individual panels which are not bendable.

In the embodiment illustrated in FIG. 4 there is located over the left end of the band 23, as viewed in FIG. 4 a container 24 which forms part of the means for directing to the treating surface the layer of flowable material in accordance with the present invention. The container 24 has the material supplied to it through a conduit 25 and the material discharges through the opening 27, the rate of discharge being controlled by the threaded screw 26 whose bottom end extends partly into the opening 27, and a device 30 is provided for guaranteeing that'the thickness of the layer is uniform and also for removing air bubbles. The elements 24-27 and 30 are extremely schematic illus trations in FIG. 4 of structure which is described in greater detail below. With this structure the layer of material 28 is applied to the treating surface formed by the outer face of the endless band 23. A plurality of rolls 29 serve to support the upper run of the band 23 in the embodiment of FIG. 4 while an elongated plate 31 is located next to the lower run of the belt 23 to prevent this lower run from deviating from the desired straight path. If desired the plate 31 may be located next to the underside of the upper run in order to support the latter in the same way as the rolls 29. The rolls 29 form spaces between themselves through which heat rays derived from suitable heating elements 35 may move to the band 23 so as to heat the material on its outer surface.

The layer 28 of the material deposited upon the treating surface moves in the direction of the anrow of FIG. 4 and as soon as it reaches the right end of the band 23 the layer of material 28 moves around with the band to the underside of the bottom run thereof and when the sheet 28 is fully hardened or at least in a partially hardened condition it contacts another sheet or plate 32 which becomes in this way joined with the endless layer 28 which thus becomes a continuously applied coating on one of the faces of the plate or sheet 32. A suitable adhesive may be used on the plate 32 for promoting the binding thereof with the coating 28, and if desired the adhesive may be applied to the outer face of the band 28. The means for applying such layers of glue or the like to the sheets is not illustrated in FIG. 4. The plate or plates 32 which are to be covered with a coating of the material 28 are moved along by the transport rolls 33 and by the pressure rolls 34 which press the plates 32 toward the bottom run of the band 23, and it is apparent that the pressure rolls 34 cooperate with the plates 31 to press the sheet 28 and the plates or sheet 32 into engagement with each other so as to provide a proper joint therebetween. Instead of pressure rolls 34 it is also possible to use a second endless band which accomplishes the same result as the pressure rolls 34 but which is carried and driven only by a pair of rolls. The heating devices 35 which are arranged beneath the upper run of the band 23 may be in the form of infra red lamps, for example. These devices are illustrated in the drawings simply as by having upwardly directed parabolic reflecting surfaces.

FIG. 5 shows an apparatus capable of manufacturing in accordance with the process of the present invention a double thickness of the material or a double sheet with an insert embedded therein. In the embodiment of FIG. 5 a pair of endless band arrangements similar to that shown in FIG. 4 are provided. An endless band 43 is carried and driven by a pair of

rolls

41 and 4 2 and forms the upper band and the elements 44-47 and 50 indicate the structure for applying to the outer treating surface of the band 43 a layer of the flowable material used in accordance with the present invention. The layer 48 of the material which is in this way applied to the outer surface of the band 43 moves in the direction of the upper arrow of FIG. 5 together with the endless band 43 whose upper run is supported by the rolls 49 and this layer 48 is of course moved by the smoothing device 50, the material 48 being derived'from the elongated opening or slot 47 of the container 44. The lower run' of the band 43 is supported by an elongated plate 51 and of course instead of this plate 51 rolls may be provided. Furthermore, such rolls or plates 49 and 51 may be replaced by endless bands each of which is carried and driven by :a pair of rolls. Below the upper run of the endless band 43 are arranged the heating devices 55 which may be in the form of infra red lamps.

A lateral guide roll 56 shown at the left of FIG. serves to guide to the outer surface of the substantially hardened sheet 48 as it moves along the lower run of the band 43 another sheet 57 in the form of a woven fabric or in the form of fleece, or the sheet 57 may be in the form of a band of any desired material or may even take the form of sepanate plates used to reinforce the double sheet manufactured with the arrangement illustrated in FIG. 5. The lower sheet of the double thickness is provided by a structure similar to that which provides the upper sheet 48. The lower assembly includes the endless band 63- which is carried and driven by the pair of

rolls

61 and 62, and the material depositing means 64-67 and '70, which is described in greater detail below in connection with FIG. 8, serves to apply the material to the outer treating surface of the band 63.

This band 63 is supported at its lower run by the rolls 69 and the element 70 serves to smooth the material delivered from the chamber 64 through the elongated slit 67 as well as to guarantee a uniform distribution of the material 68 on the treating surface of the band 63. A plate 71 is used to support the upper run of the band 63, and just above the lower run of this band are located the infra red heating lamps 75, for example. Thus, with the structure shown in FIG. 5 a pair of sheets are simultaneously formed and as they move to the right, as viewed in FIG. 5, in engagement with each other so as to be united to each other they have placed therebetween the third band or sheet 57 which serves to reinforce the final construction.

FIGS. 6 and 7 illustrate an endless band according to the present invention which serves as a pressure means and which may be used, for example, instead of the rolls 34 of FIG. 4.

In FIG. 6 the pressure means formed by the endless band is shown as being used to press downwardly upon the sheet of plastic which has already been formed and which is in engagement with the other sheet or plate to which it is to be joined. Of course, the arrangement may be reversed so that the sheet 164 and plate 165 of FIG. 6 are located in engagement with the upper run of the band 163 shown in FIG. 6 so that this band then presses upwardly against the sheet 164 so as to move the latter into engagement with the plate 165 and press the

elements

164 and 165 together with a force which will provide, a proper joint therebetween. Only one end of the band is shown in FIG. 6 since the other end is the same and the upper and lower runs are simply continuations of the structure shown in FIG. 6.

A polygonal roll 80 carries a chain band 81 in the form of a plurality of individual grates which are linked together so as to form an endless band, and the runs of thi band are supported by the rolls 82, as indicated diagrammatically in FIG. 6. An elongated hollow endless pusher band 163 is carried by the chain band 81, and this band 163 serves to press the sheet 164 downwardly against the plate 165 moving to the right with the sheet 164, as viewed in FIG. 6. The hollow interior of the band 163 is filled with an elastic medium so that the longitudinal central portion of the outer wall of the band 163 bulges outwardly to the dot-dash line 166 indicated in FIG. 6. Therefore, as the endless band rotates it will engage the sheet 164 for the first time at the point 167 which is located by the distance a in front of the point 169 where full pressure is applied. As a result a pressure is applied by pressure applying means in the shape of an isosceles triangle whose base extends transversely across the sheet 164 at the point 169 and whose apex is rounded and located at the point 167. Thus, the pressure band 163 provides first a wedge-like action so that air bubbles located between the sheet 164 and the plate 165 will be squeezed outwardly toward the outer side edges of the sheet.

FIG. 7 shows the structure of FIG. 6 in transverse cross section at an enlarged scale, and the supporting roll 82 is shown in FIG. 7 supporting the grate 81, FIG. 7 also showing the band 163 in engagement with the chain grate 81. As may be seen from FIG. 7 the hollow interior 170 of the band 163 has the cross section of an isosceles triangle with the apex of the triangle directed toward the sheet 164 and the base of the triangle located I at the part of the belt which is engaged by the chain grate 81. Therefore, at the outer wall of the band 163 this band is of a lesser thickness along its longitudinal central line than at its side edges. The interior 170 is filled with a metal alloy of low melting point. Any metal alloy having a melting point somewhat below C. may be used. In particular Woods alloy may be used, this alloy being composed of 25% lead, 50% bismuth, l2 /2% cadmium, and l2 /z% tin, and this alloy having a melting point of approximately 60 C., or Roses metal may be used, this latter alloy being composed of approximately 50% bismuth, 25% tin, and 25% lead and having a melting point of approximately 95 C. In order to heat the alloy located within the hollow space 170 of the belt, metal electrodes 171 are carried by the belt at its side walls and extend into the hollow interior thereof, these electrodes having outer free ends which slide along the bus bars 172 which serve to provide in the electrodes 171 the necessary heating current for melting the alloy within the hollow band 163.

FIG. 8 shows in a partly diagrammatic manner the details of an embodiment of the invention used for applying the material to the treating surface. A mixing container 101 is provided and a stirrer extends into this container. The stirrer 102 serves to mix thoroughly with the casting resin the additional component which reduce the hardening time thereof so that this latter catalyst becomes thoroughly mixed with the casting resin. The outlet 103 serves to direct the material from the container 101 into a vacuum chamber 104 communicating with a conduit 105 which leads to a vacuum pump which serves to maintain the desired vacuum within the vacuum chamber 104 which is not illustrated in the drawings. Thus, the degassed mass leaves the vacuum chamber 104 and is moved by a metering pump 106 along the conduit 107 into the entrance pipe 108 of the depositing means. The conduit 103 serves to provide a thin stream of the material from the container 101 into the vacuum chamber 104 so that a thorough degassing takes place.

The pipe 108 serves to deliver the material to a receiving chamber 109 and from the receiving chamber 109 the material moves to a discharging chamber 112. A means is provided between the

chambers

109 and 112 for providing communication therebetween and for guaranteeing uniform flow of the material from the receiving chamber 109 to the delivering chamber 112, and this means takes the form of a partition wall formed between and common to the

chambers

109 and 112 and formed along its length with a plurality of openings 110 one of which is shown in FIG. 8. Each of the openings 110'is of a frustoconical configuration and has its smaller end directed toward the discharge chamber 112. The top wall of the chamber 109 carries a plurality of screw members 111 having bottom conical ends which respectively extend into the openings 110 and which have the same inclination of the surfaces of the openings so that by adjusting the positions of the bottom ends of the screws 111 with respect to the openings 110, it is possible to regulate the flow of the material from the chamber 109 to the chamber 112, and thus a uniform flow along the entire length of the device may be provided.

The bottom wall of the chamber 112 is in the form of a plate 113 fixed to a rearwardly directed flange of the rear wall of the chamber 112 by screws 114 having heads 115 which engage the underside of the plate 113 and which are of a larger diameter than the width of slots 116 through which the screws 114 respectively extend. With the screws 114 which are carried by nuts at their top ends, as viewed in FIG. 8, it is possible by cooperation of the slots 116 with the shanks of the screws to adjust the position of the plate 113 so that the distance between its right edge and the right wall of the chamber 112, as viewed in FIG. 8, may be regulated so that the width of the discharge gap of the discharge chamber 112 may in this way be adjusted. The plate 113 is provided with an unillustrated hollow space which contains a cooling medium. The mass which reaches the cylindrical polymerizing surface 117 through the gap forms on the surface 117 the sheet 118. At the end of the material depositing device there is provided at one of the end faces of the polymerizing roll 117 a lateral sealing plate 119 which in an unillustrated manner is hollow and cooled with water and which serves to determine the width of the sheet. Of course, a similar sealing plate 119 is located at the opposite end of the apparatus, which is to say at the opposite end of the roller 117.

In order to accurately adjust the thickness of the sheet 118 a linear distributor element 128 is located over the polymerizing surface 117. The distributor element 120 is formed out of a length of sheet metal which is rolled around at one end thereof and which has its rolled end welded at 121 to the remainder of the sheet metal so as to provide the elongated hollow chamber 122 to which cooling water is supplied by the conduit 123. Of course, another conduit 123 may be provided so that cooling water may be continuously circulated through the hollow chamber 122 of the distributor 120. In order to be able to adjust the distributor 129 to different distances from the polymerizing surface 117, the vertical wall of the distributor 120 is formed with a plurality of slots 124 which extend vertically and through which extend screw members 125 which serve to clamp the distributor 1220 to the front wall of the

chambers

109 and 112. Thus, by loosening the screws 125 the height of the distributor 120 may be adjusted and then the screws 125 may be tightened so as to clamp the distributor 120 in its adjusted elevation.

FIG. 9 of the drawings illustrates a polymerizing drum 130 having an outer cylindrical polymerizing surface for manufacturing a sheet according to the present invention. The sheet 131 is formed on the polymerizing surface in the manner described above, this sheet 131 being applied in the form of material 132 from a material depositing means having the above-described construction. A pattern drum 133 is located next to the polymerizing drum 139 and is provided with projections 134 extending radi ally outwardly from the axis of the pattern drum 133 in accordance With a predetermined pattern. A supply roll 135 receives a layer of material 137 from the supply container 136 and guides this layer in the form of a cohesive coating 138 to the pattern drum 133 where the outer ends of the projections 134 engage the layer 138 to remove the latter from the roll 135 and to deposit the material in the pattern determined by the shape of the projections 134 onto the polymerizing surface of the polymerizing roll 130, portions 140 of the material deposited on the surface of the drum 130 being shown in FIG. 9. It is after these pattern portions are deposited on the drum that the latter receives the material 131 which is formed into the sheet 132. The material 137 which is used to form the pattern 140 is the same material which is used for the sheet 132 and thus becomes polymerized in the same way. However, the material 137 may have a different color, for example. Thus, when the finished sheet is removed from the polymerizing drum 130 it has embedded in its upper surface portion, as viewed in FIG. 9,

10' the pattern 141 whose particular design is controlled by the pattern drum 133.

FIG. 10 of the drawings shows a process according to the present invention for manufacturing tubes. A pair of sheets 240 manufactured according to the present invention move simultaneously to the right, as viewed in FIG. 10. Such a pair of sheets may be simultaneously manufactured by a structure as shown in FIG. 5 where the upper and lower assemblies are spaced from each other so that the two sheets issuing from the right of the structure of FIG. 5 have between them the space indicated between the sheets 240 at the left of FIG. 10. Between these sheets which are moving together toward the right are located in succession a plurality of elongated rods of cylindrical cross section, and these rods may be inserted between the sheets by hand, for example. Also, suitable devices such as the nozzles referred to above may be provided for spraying a coating of adhesive on the faces of the sheets which are directed toward each other. FIG. 10 shows a rod 241a which has just been inserted between the sheets 240. The rod 241b was inserted just before the rod 241a. Between these two rods a pair of pressing members 242 come together so as to press the two sheets together as they continue to move toward the right, as viewed in FIG. 10, and due to the adhesive put between these sheets, as indicated in FIG. 10, they stick to each other. Of course, the sheets may be in such condition that their surfaces which are to be joined to each other are not yet fully hardened and they may stick to each other in a sufficiently satisfactory manner simply by their still somewhat plastic condition. The pressure members 242 which come together in the manner indicated in FIG. 10 may each form a part of a toothed wheel which turns about an axis perpendicular to the direction of movement of the sheets 240 in such a way that the members 242 participate in the movement of the sheets and at the same time move toward and away from the sheets so that the two members 242 reach the position indicated in FIG. 10 at the proper moment. After the sheets have been joined in this way a pair of additional pressure members 243 push the sheets together between a pair of successive rods, as is shown in FIG. 10 between the rods 24-112 and 2410, the latter rod having been inserted before the rod 24117. Any suitable mechanism is moved for moving the pressure members 243 toward and away from each other in the proper synchronism. Preferably the speed of rotation of the toothed wheel having the teeth 242 is such that the latter teeth or pressure members 242 engage the sheets at a rate somewhat faster than the rate of the cycles of operation of the pressure members 243 so that the sheets tend to become upset just before they are put together by the members 243. The pressing of the sheets together by the members 243 provides a tube which closely surrounds the rod, as is indicated at the right of FIG. 10 where the rod 241d is shown surrounded by the pair of sheets which are joined together. At this time a pair of blades 245 come together under the actuation of a suitable mechanism so as to cut the rod 241d and its covering from the oncoming series of rods covered with sheets. The pair of flanges of the sheets extending to the right and left from the rod 241d, as viewed in FIG. 10, are removed in any suitable way so as to provide the structure shown in FIG. 11, namely a rod 241e sheathed within a tubular closure 2492. If it is desired to have a hollow tube then the rods are provided with a suitable coating which will prevent them from sticking to the sheet material, and after a structure as shown in FIG. 11 is provided the rod may then be removed from the interior of the tube so that a hollow elongated tube as shown in FIG. 12 is provided in this way. The structure shown in FIG. 10 is moved to the right of FIG. 10 in any suitable conveyor which in this case is not in the form of a continuous band but is rather in the form of a series of chain elements or panels which are spaced from each other so that in the spaces between the panels of the conveyor the

elements

242, 243

and 245 may work, these elements being moved in synchronism with the conveyor so that they move into and out of the spaces between the sections of the conveyor without engaging the sections.

FIG. 13 shows the drive for a smoothing device such as that indicated in FIG. 4 by the reference character 30 and in FIG. 5 by the reference character 50. The smoothing device consists essentially of an elongated linear body located relatively close to the polymerizing surface and moves to the right and left transversely with respect to the surface. The polymerizing surface of a rotating drum, for example, is indicated at 250 in FIG. 13, and over this surface is shown the movable smoothing element 251. The structure for depositing the plastic material onto the polymerizing surface 250 is not shown. The smoothing element 251 is fixed to an elongated bar 252 having ends respectively extending into the bearing blocks 253 and 254, these bearings supporting the bar 252 and the smoothing element 251 for longitudinal shifting movement in the direction of their lengths, which is to say in a direction substantially parallel to the axis of rotation of the polymerizing drum 250. The bearings are such that they have non-circular openings of square cross section, for example, which receives portions of the bar 252 which also are of square or mating cross section so that while the bar 252 together with the smoothing elements 251 can shift back and forth they cannot turn about the axis of the bar 252.

The bar 252 is fixedly connected to a pair of guide members 255 which receive into the space defined be tween themselves a portion of a collar 256 which is fixed to a shaft 257 supported at its right end, as viewed in FIG. 13, by the bearing 254 for rotation about its axis. Also, the bearing 254 supports the shaft 257 for longitudinal shifting movement. The left end of the shaft 257, as viewed in FIG. 13 terminates in an elongated hollow tubular portion 258 open at its left extremity, as viewed in FIG. 13, and receiving a drive shaft 259 which is supported by the bearing 253 and which is driven by pulley 260 fixed to the left end of the drive shaft 259. The hollow tubular portion 258 of the shaft 257 is formed with an elongated axially extending slot 262, and the drive shaft 259 carries a cross pin 261 which extends into the slot 262 so that in this way the shaft 257 is constrained to rotate together with the drive shaft 259 but at the same time is axially shiftable with respect thereto. The hollow tubular end portion 258 of the shaft 257 fixedly carries as by having formed integrally therewith an annular cam 263 which is shaped as indicated in FIG. 13 so that it has a periphery similar to that of a helix. The bearing 253 fixedly carries a block 265 formed with a notch 264 which receives the periphery of the cam 263. Thus, as the shaft 257 is driven by the shaft 259 the periphery of the cam 263 by cooperating with the notch 264 causes the shaft 257 to be shifted longitudinally back and forth, and by cooperation of the collar 256 with the guides 255 the bar 252 as well as the smoothing element 251 will also be shifted longitudinally back and forth.

With the embodiment of FIG. 13 the elongated smoothing element 251 moves in a direction parallel to the polymerizing surface. In the embodiment shown in FIG. 14 the smoothing element moves radially with respect to the axis of rotation of the polymerizing surface so as to move toward and away from the polymerizing surface. The polymerizing surface 278 is shown in FIG. 14 fragmentarily and in cross section so that it appears as an arc of a circle. The layer of material 271 which forms a sheet according to the invention is shown on the polymerizing surface 278 in cross-section, and the structure for depositing the flow of material on the polymerizing surface is omitted from FIG. 14. A hollow tubular smoothing and pressing element 272 is located over the polymerizing surface 278 with the material 271 extending between the surface 278 and the element 272, and the interior hollow space 273 of the elongated tubular element- 272'may be cooled as by having cooling water circulated therethrough. The elongated hollow tubular member 272 has fixed thereto a bar 274 which extends upwardly through a suitable bearing 275 which guides the bar 274 for vertical reciprocating movement, the bar 274 as well as the opening of the bearing 275 being noncircular so that the bar 274 cannot turn about its axis and is constrained only to vertical reciprocating movement.

The bar 274 terminates at its top end in a head portion 276 which is bifurcated and which receives between its bifurcations an elongated lever 279, each of the bifurcations of the bar 276 being formed with an elongated slot 277 and the lever 279 carrying a cross pin 270 which respectively extends into the slots 277. Only one of the bifurcations and slots 277 is visible in FIG. 14. The lever 279 is supported by a pivot pin 280 for pivotal turning movement about a stationary axis, and the right end of the lever 279 is bifurcated and receives between its bifurcations 281 an eccentric 282 which is fixed to a shaft 283 for rotation therewith, this shaft 283 being driven by a motor 285 which is carried by the support 284 which also supports shaft 283 for rotation about its axis. Thus, with the structure of FIG. 14 while the motor 185 drives the shaft 283 the eccentric 282 will rotate with theshaft and will cooperate with the bifurcated portion 281 of the shaft 279 to turn the shaft 279 up and down through a relatively small angle about the pivot axis formed by the shaft 280, and as a result the bar 274 will shift slightly up and down so as to move the elongated tubular member 272 also up and down through a slight distance. This slight up and down movement of the bar 272 will also cause the layer of material deposited on the polymerizing surface to become uniformly distributed thereover.

In the above description reference has been made to webs of fabric, fleece, or the like, which are located between or against the sheets constructed according to the present invention so as to become joined therewith. These webs may be made of a woven fabric of natural or synthetic fibers as well as a fabric woven from metal wires such as wires made of copper or bronze and also glass and asbestos fibers may be used in some cases. It is also possible to use fleece made of natural or synthetic glass and asbestos fibers. Also, in many cases it is desirable to use absorbent layers such as sheets of cardboard or paper with the sheets of the present invention.

As a specific example of operations according to the present invention, referring to FIG. 8, the container 101 may hold approximately kg. of the casting resin and catalyst according to the present invention. For example this 75 kg. may be composed of an unsaturated polyester together with a catalyst such as benzoyl peroxide, the latter being added in such an amount as to hasten the hardening time of the unsaturated polyester that it will harden within the period of time available on the rotating polymerizing surface. Both of these components are mixed thoroughly in the container 101 by the stirrer 10-2 and while the mixing is taking place the conduit 103 is closed, the mixing being continued beyond the absolute minimum required. The vacuum pump connected to the conduit 165 places the interior of the chamber 104 at a pressure of mm. of mercury. After the material has been mixed to the desired extent in the container 181 the conduit 193 is opened and the outlet of-this conduit is in the form of an elongated narrow slit so that a thin stream of the material is sucked into the container 1&4 and the air bubbles drawn into the mixture during the mixing thereof burst within the vacuum chamber 164. This degassing of the material is necessary since otherwise the trapped .air bubbles would provide a porous construction of the sheet. The container 101 and the vacuum chamher 194 are dimensioned in such a way that it is at the most necessary to provide an additional batch of material once an hour.

The pump 106 which may be in the form of a screw pump supplies the raw material at a uniform rate into the receiving chamber 109 irrespective of whether the conduit 193 is opened or closed. The material is then delivered from the chamber 109 to the polymerizing surface in the manner described above in the detailed description of FIG. 8. The drive for the polymerizing roll 117 is adjustable so that the latter may be driven at a speed which is suitable for the particular material which is being worked with. Moreover, a drive is transmitted from the polymerizing roll 117 to the pump 106 so that the latter is always driven at a rate which is proportional to the speed of drive of the polymerizing roll 1.17. In this way it is assured that the raw material supplied to the roll will always have the same thickness irrespective of whether the polymerizing drum is driven at a relatively slow or fast rate. Moreover, the speed of drive of the drum controls the thickness of the layer thereon. By adjusting this drive it is possible to obtain a variation from 1 to 3, which is to say the thickness of the sheet may be regulated to anywhere between 300 and 900 microns. Within the interior of the drum 117 is located a bath which is controlled by .a suitable thermostat so as to be heated to the desired temperature. Before the raw material reaches the polymerizing surface a suitable pattern may be placed thereon as was described above.

The action of the smoothing devices such as the device 30 of FIG. 4 is controlled so that this device swings up and down at such a speed that the desired results are produced. For example, depending upon the speed of rotation of the polymerizing drum, the temperature of the material and the components thereof the smoothing device is operated in such a way as to provide the desired smooth surface. When the sheetis removed by a roll such as the roll 13 of FIG. 3 and when it has not yet reached its 100% final condition as to degree of polymerization and hardness upon further cooling there are no noticeable changes such as shrinking, embrittlement, and the like. A pre determined amount of ripening may be desired, and in this case the sheet is guided through an unillustrated ripening chamber where it is placed for a period of 200- 300 seconds in an atmosphere having a temperature of IOU-120 C. In general the heating may take place with the use of infra red lamps, but also it is possible to use vapors such as steam for this purpose.

During the continued movement of the sheet it is provided on one face with a layer of adhesive so as to be capable of being joined with another sheet or plate, as described above. A particularly suitable adhesive is a polyurethane glue made by the Bayer Company. This glue requires as a solvent esters of low boiling point which provide a strong swelling of the sheet after a relatively long period'of time while the sheet is still freshly It is necessary therefore that the evaporation of,

made. the solvent, after the principal portion thereof has evaporated without any particular assisting means during a period of approximately 120 seconds, be completed in a period of approximately 60 seconds while the infra red heating is maintained. The effect produced by this subsequent heating cannot be replaced by a longer evaporating time and not by any additional circulation of air under pressure.

With an arrangement as shown in FIG. 2 the sheet 12 must cool down to a temperature of approximately 50 C. before it is joined with one of the plates 17, and this cooling takes place simply during the free movement of the sheet to the rolls in in a period of approximately l53() seconds due to the natural cooling of the material. Where the plates 17 are relatively thick so that they hold heat longer it may be necessary to provide an additional cooling medium such as providing cooling streams of air.

in the above-described structure the endless bands which have the polymerizing surfaces may be moved .at a rate of approximately 3 cm. per second. The sheet which is mately 30 seconds to cool off, approximately seconds to evaporate and approximately 60 seconds for such evaporation when the temperature is elevated, again 30 seconds for cooling and finally 60 seconds for pressing. Thus, the total treating time for the sheet after it leaves the polymerizing surface is approximately 300 seconds.

Where sheets of reinforcing fabric or the like are inserted between a pair of sheets of the invention which are joined together in the manner described above in connection with FIG. 5, for example, these inserted webs may be impregnated with the same resin as that of which the sheets are composed. Where it is possible to use an inexpensive resin which will fade in the light such as a phenol resin which is not non-fading, then this resin may be used to impregnate the inserted reinforcing web while the outer layers are then made of a more expensive but non-fading polyester resin.

Although in the above-described process and apparatus reference has been made to the spraying onto the polymerizing surface of a suitable agent which willprevent sticking of the plastic to the surface, it is also possible to mix together with the plastic material an agent which will prevent sticking thereof on the polymerizing surface, and in this case of course it is unnecessary to deposit onto the polymerizing surface a coating to prevent sticking.

The rhythmically moving smoothing devices such as those shown in FIGS. 13 and 14 and described above cause gas bubbles to be freed from the layer of material which has not yet fully hardened.

In connection with FIG. 2 reference has been made above to inert gases filling the chamber 101, these gases being derived from the inert gases which are under pressure and used in connection with the nozzles 3 and 4 for spraying the material 3a and 12 onto the polymerizing drum 1. However, it is also possible to fill the interior of the chamber 1a with any gas from any suitable source, this gas having no undesirable influence on the process, and

it is not absolutely essential to employ for the nozzles 3' and 4 a gas under pressure which will fill the chamber 1a. Instead of a chamber 1a it is also possible to use any suitable tank or the operations may take place under a suitable hood.

,Where additional sheets, plates, or the like are to be joined to the sheets made according to the present invention, these sheets may be preheated so as to form a good bond with the plastic sheets, and also it is possible to provide on the surfaces which are to contact and to become bound together a catalyst which will promote the union of the sheet with the additional sheets, plates, or the like. Of course, rapid cooling and quenching of the plastic sheet may be provided as it leaves the polymerizing surface.

In those cases where the sheet is not yet in a fully hardened condition as it leaves the polymerizing surface, it may be desirable to provide for ripening of the sheet over a predetermined length of time, and for this purpose the sheet maybe divided into sections or folded into layers which form overlying sections and the sections of the sheet may be prevented from sticking to each other by suitable intermediate layers such as sheets of paper inserted between the sections of the sheet or coatings of powder, and then the sheet may be stored at any desired location for ripening purposes. located in a container which is insulated at all sides against the transfer of heat.

While the sheet is still in a somewhat plastic condition aroll having a profile of predetermined pattern marked thereon may be pressed against the sheet so as to press a desired pattern into the sheet.

The sheets of the invention can also be corrugated so as to have a shape similar to that of one of the sheets of FIG. 10, for example, by passing the sheets while they are still not in fully polymerized condition through suitably shaped rolls which corrugate the sheets, the sheets being thereafter heated. The corrugated sheets which are formed in this way may be cut in any desired way so as to- For this purpose the sheet may be provide individual channels, for example, or so as to provide desired lengths of corrugated rigid plastic. Of course,

these sheets may be joined together in the manner described above in connection with FIG. 10.

In connection with FIG. 10, it is possible to use instead of the bars described above a foam which is used as a core within the tube, such a foamy material serving as an insulation against heat and noise. Forexample the inserts maybe in the form of foam rubber.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of process and apparatus for making sheet material differing from the types described above.

While the invention has been illustrated and described as embodied in process and apparatus for making plastic sheet material having desired properties, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will also fully reveal the gist of the present invention that others can by applying current Knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed asnew and desired to be secured by Letters Patent is:

1. In a continuuous process for manufacturing an article composed at least in part of a sheet formed from a polymerizable, thermosetting casting resin selected from the group consisting of unsaturated polyesters, phenol and ethoxylene casting resins, the steps of continuously applying to a revolving support a layer of predetermined thickness of a fiowable mixture of a casting resin and of an agent adapted to reduce the hardening time of said casting resin at a predetermined elevated temperature to a predetermined relatively short period of time, said mixture being adapted to harden at said predetermined elevated temperature without giving off any appreciable amount of gaseous products, so as to form a layer of said mixture on said revolving support; placing on said support before it is engaged by said fiowable mixture a material separate from said fiowable mixture in a predetermined pattern so that the pattern of said separate material becomes embedded in the surface of the fiowable mixture which engages the revolving support; heating said mixture on said support to said predetermined elevated temperature; adjusting the speed of said revolving support relative to said predetermined period of time in such a manner that said mixture will be substantially hardened prior to completion of one revolution of said revolving support; and continuously separating the thusformed hardened sheet of casting resin from said support, whereby in a single application and in a continuous manner a sheet of said predetermined thickness is formed of said polymerizable, thermosetting casting resin.

2. In a continuous process for manufacturing an article composed at least in part of a sheet formed from a polymerizable, thermosetting casting resin selected from the group consisting of unsaturated polyester, phenol and ethoxylene casting resins, the steps of continuously applying to a revolving support a, layer of predetermined thickness of allowable mixture of a casting resin and of an agent adapted to reduce the hardening time of said casting resin at a predetermined elevated temperature to a predetermined relatively short period of time, said mixture being adapted to harden at said predetermined elevated temperature without giving off any appreciable amount of gaseous products, so as to form a layer of said mixture on said revolving support; heating said mixture on saidsupport to said predetermined elevated temperaiii ture; adjusting the speed of said revolving support relative to said predetermined period of time in such a manner that said mixture will be substantially hardened prior to. completion of one revolution of said revolving support; and continuously separating the thus-formed hardened sheet of casting resin from said support, whereby in a single application and in a continuous manner a sheet of said predetermined thickness is formed of said polymerizable, thermosetting casting resin.

3. In a process as defined in claim 2, the step of vibrating said mixture on said revolving support so as to smoothen and to remove gas bubbles from said layer during hardening of the same.

4. In a continuous process for manufacturing an article composed at least in part of a sheet formed from a polymerizable, thermosetting casting resin selected from the group consisting of unsaturated polyesters, phenol and ethoxylene casting resins, the steps of continuously applying to a revolving support a layer of predetermined thickness of a fiowable mixture of a casting resin and of an agent adapted to reduce the hardening time of said casting resin at a predetermined elevated temperature to a predetermined relatively short period of time, said mixture being adapted to harden at said predetermined elevated temperature without giving off any appreciable amount of gaseous products, so as to form a layer of said mixture on said revolving support; applying to said flowable mixture before it engages said revolving support an additional material which prevents said fiowable mixture from Sticking to said support; heating said mixture on said support to said predetermined elevated temperature, adjusting the speed of said revolving support relative to said predetermined period of time in such a manner that said mixture will be substantially hardened prior to completion of one revolution of said revolving support; and continuously separating the thus-formed hardened sheet of casting resin from said support, whereby in a single application and in a continuous manner a sheet of said predetermined thickness is formed of said polymerizable, thermosetting casting resin.

5. In a continuous process for manufacturing an article composed at least in part of a sheet formed from a polymerizable, thermosetting casting resin selected from the group consisting of unsaturated polyesters, phenol and 'ethoxylene casting resins, the steps of continuously applying to the outer face of a revolving drum a layer of predetermined thickness of a fiowable mixture of a casting resin and of an agent adapted to reduce the hardening time of said casting resin at a predetermined elevated temperature to a predetermined relatively short period of time, said mixture being adapted to harden-at said predetermined elevated temperature without giving off any appreciable amount of gaseous products, so as' to form a layer of said mixture on said revolving drum; heating said mixture on said drum to said predetermined elevated temperature; adjusting the speed of said revolving drum relative to said predetermined period of time in such a manner that said mixture will be substantially hardened prior to completion of one revolution of said revolving drum; and continuously separating the thusformed hardened sheet of casting resin from said drum, whereby in a single application and in a continuous manner a sheet of said predetermined thickness is formed of said polymerizable, thermosetting casting resin.

6. In an apparatus for manufacturing an article composed at least in part of a sheet formed from a polymerizable thermosetting casting resin in plastic condition, in combination, a receiving chamber for receiving the resin in fiowable form together with a component which reduces the hardening time thereof; a discharge chamber formed with an elongated straight slot-shaped discharge opening for discharging the material in fiowable sheet form onto a treating surface; means associated with and providingcomrnunication between said receiving and discharge chamber and maintaining uniform the rate of flow of the material from said receiving chamber to said discharge chamber so that the material flows through said elongated straight slot-shaped discharge opening at a substantially uniform rate in the form of a flowable sheet of substantially uniform thickness, said flowable sheet of uniform thickness being deposited onto said treating surface; elongated hollow shaping means located adjacent to and extending in direction of said elongated straight slotshaped discharge opening and simultaneously adjacent to and spaced from said treating surface a distance equal to the desired thickness of the finished sheet material so as to serve as shaping means for said flowable sheet material; and means for admitting cooling medium into said hollow shaping means for cooling said shaping means during shaping.

7. In an apparatus for manufacturing an article composed at least in part of a sheet formed from a polymerizable thermosetting casting resin in plastic condition, in combination, a receiving chamber for receiving the resin in flowable form together with a component which reduces the hardening time thereof; a discharge chamber formed with an elongated straight-shaped discharge opening for discharging the material in flowable sheet form onto a treating surface; means associated with and providing communication between said receiving and discharge chamber and maintaining uniform the rate of How of the material from said receiving chamber to said discharge chamber so that the material flows through said elongated straight slot-shaped discharge opening at a substantially uniform rate in the form of a flowable sheet of substantially uniform thickness, said flowable sheet of uniform thickness being deposited onto said treating surface; elongated hollow shaping means located adjacent to and extending in directions of said elongated straight slot-shaped discharge opening and simultaneously adjacent to and spaced from said treating surface a distance equal to the desired thickness of the finished sheet material so as to serve as shaping means for said flowable sheet material; means for admitting cooling medium into said hollow shaping means for cooling said shaping means during shaping; and means for mounting said elongated hollow shaping means adjustably in a direction towards and away from said treating surface so as to adjust thereby the thickness of the finished sheet material.

References Cited in the file of this patent UNITED STATES PATENTS 2,072,105 Fischer Mar. 2, 1937 2,144,548 Safford Jan. 17, 1939 2,198,621 Izard Apr. 30, 1940 2,361,374 Abbott Oct. 31, 1944 2,438,089 Carson Mar. 16, 1948 2,448,585 Fuller Sept. 7, 1948 2,495,640 Muskat Jan. 24, 1950 2,503,518 Slaughter Apr. 11, 1950 2,537,126 Francis Jan. 9, 1951 2,558,773 Mulloy et a1. July 3, 1951 2,559,649 Little et a1. July 10, 1951 2,579,138 Burness Dec. 18, 1951 2,590,186 Land Mar. 25, 1952 2,643,700 Havens June 30, 1953 2,665,450 Lindquist Jan. 12, 1954 2,771,388 Rocky Nov. 20, 1956 2,799,609 Dalton July 16, 1957 FOREIGN PATENTS 546,469 Great Britain July 15, 1942

Claims

7. IN AN APPARATUS FOR MANUFACTURING AN ARTICLE COMPOSED AT LEAST IN PART OF A SHEET FORMED FROM A POLYMERIZABLE THERMOSETTING CASTING RESIN IN PLASTIC CONDITION, IN COMBINATION, A RECEIVING CHAMBER FOR RECEIVEING THE RESIN IN FLOWABLE FORM TOGETHER WITH A COMPONENT WHICH REDUCES THE HARDENING TIME THEREOF; A DISCHARGE CHAMBER FORMED WITH AN ELONGATED STRAIGHT-SHAPED DISCHARGE OPENING FOR DISCHARGING THE MATERIAL IN FLOWABLE SHEET FORM ONTO A TREATING SURFACE; MEANS ASSOCIATED WITH AND PROVIDING COMMUNICATIN BETWEEN SAID RECEIVEING AND DISCHARGE CHAMBER AND MAINTAINING UNIFORM THE RATE OF FLOW OF THE MATERIAL FROM SAID RECEIVING CHAMBER TO SAID DISCHARGE CHAMBER SO THAT THE MATERIAL FLOWS THROUGH SAID ELONGATED STRAIGHT SLOT-SHAPED DISCHARGE OPENING AT A SUBSTANTIALLY UNIFORM RATE IN THE FORM OF A FLOWABLE SHEET OF SUBSTANTIALLY UNIFORM THICKNESS, SAID FLOWABLE SHEET OF UNIFORM THICKNESS BEING DEPOSITED ONTO SAID TREATING SURFACE; ELONGATED HOLLOW SHAPING MEANS LOCATED ADJACENT TO AND EXTENDING IN DIRECTIONS OF SAID ELONGATED STRAIGHT SLOT-SHAPED DISCHARGE OPENING AND SIMULTANEOUSLY ADJACENT TO AND SPACED FROM SAID TREATING SURFACE A DISTANCE EQUAL TO THE DESIRED THICKNESS OF THE FINISHED SHEET MATERIAL SO AS TO SERVE AS SHAPING MEANS FOR SAID FLOWABLE SHEET MATERIAL; MEANS FOR ADMITTING COOLING MEDIUM INTO SAID HOLLOW SHAPING MEANS FOR COOLING SAID SHAPING MEANS DURING SHAPING; AND MEANS FOR MOUNTING SAID ELONGATED HOLLOW SHAPING MEANS ADJUSTABLY IN A DIRECTION TOWARDS AND AWAY FROM SAID TREATING SURFACE SO AS TO ADJUST THEREBY THE THICKNESS OF THE FINISHED SHEET MATERIAL.