IE83516B1 - A method of embossing a pvc coated fabric material - Google Patents

Description

The present invention relates to a method of embossing a PVC coated fabric material comprising initially printing a front face of a continuous web of the material and then feeding the web on a conveying system comprising at least one drive drum and a plurality of idler rollers through a number of workstations.

Such PVC coated fabric is made by applying a topping PVC material followed by a foamed paste layer and a laminating material onto a release face of a paper substrate material. A fabric backing layer is then applied over the laminating layer to form a composite. The paper substrate is then removed from the composite.

There are certain major problems in the embossing of PVC coated fabrics because it is usually carried out at relatively high speeds or it is uneconomic and if it is carried out at relatively high speeds, then considerable difficulty is encountered in controlling the web and in making sure that the embossing is symmetrical and carried out accurately. Thus it is very important that the web does not move laterally or does not stretch in the longitudinal direction than across it’s width.

Further, after the web has been embossed, it is necessary then to lacquer the web.

This is required to effectively cure and retain the print. A problem with this then again is because the surface being lacquered is uneven, it is very important that the lacquering be carried out accurately. The uneven surface can present considerable problems and again the major problem is to ensure that the web is accurately aligned as it is carried through the lacquering operation.

A further problem is to ensure that the web is heated to a uniform and correct temperature as it is led through the embossing heads.

The present invention is particularly directed towards provided an improved method of heating the web prior to embossing so as to ensure that the web is uniformly heated across its length as it is being embossed and thus ensure that the embossing is carried out uniformly.

The present invention is directed towards these and other objects.

S.ta1emen1s_of_.lnMenIio.n According to the invention, there is provided a method of embossing a PVC coated fabric material comprising: initially printing a front face of a continuous web of the material; and then feeding the web on a conveying system comprising at least one drive drum and a plurality of idler rollers through a number of workstations and carrying out the steps of:- delivering the web from a roll through an accumulator; leading the web around most of the outer periphery of an enlarged heater drum to preheat the web by passing hot fluid through the interior of the drum; applying infrared heat to the front face of the web as it exits the heater drum to heat the web to a final temperature of between 160‘-’C to 1909C; leading the web through a pair of hollow rollers, namely a hardened steel patterned embossing roller and a nipping roller, the nipping roller being of an elastic material to apply a pressure against the web, driving the nipping roller by a diametrically opposed steel drive roller, exerting a pressure on the nipping roller by the drive roller to exert a constant contact pressure on the web across it’s width, simultaneously delivering cooling water through the hollow rollers as the web is being embossed, leading the web through a further set of hollow idler rollers, simultaneously delivering cooling water through the idler rollers as the embossed web is being led therethrough; stretching the web as it exits the embossing rollers by leading the web through further rollers; and lacquering the front face of the web by:- delivering the web across two in-line alignment rollers mounted together on a separate pivotal carriage; sensing the position of the edge of the web downstream of the alignment rollers by delivering portion of a constant jet of air against one face of the web adjacent its edge; collecting the air transmitted across the web; measuring the amount of air collected as an indication of the edge position of the web; causing pivotal movement of the carriage in response to the edge position sensed; leading the web to a lacquering station; applying lacquer to the front face of the web by leading the web between two rollers, one of which is a lacquer applying roller being partially submerged in a lacquer containing bath for the take up of lacquer thereon and then scraping excess lacquer from the face of the web; heating the front face of the web to a temperature of between 85‘-‘C and 1159C to cure the lacquer; and cooling the web after lacquering.

By using both heating on the back of the web and also on the front of the web by infrared heating, a very satisfactory even heating is provided which assists greatly in the embossing providing a better embossing than heretofore has been achieved. it is vital that the embossing rollers are kept suitably cool because if not, difficulties arise.

It has been found that by using an embossing roller of one material which is hard and contains the pattern and not using a roller with a corresponding pattern, better embossing has been achieved with more gentle transition between the hills and hollows of embossing.

Ideally, the web is cooled by leading the web around idler drums through which cooling water is pumped. It has been found that it is very important to cool the web as it is stretched because this tends to fix the embossing and provides a better product.

In one embodiment of the invention, the web is heated to between 170‘—’C and 1809 prior to embossing. This has been found to be the most suitable way. The heating fluid is steam or hot oil. ldeally, the heating of the web after lacquering is carried out within the range 8590 to 1159C.

Preferably, the heating of the web after lacquering is carried out at approximately 100‘-’C. lt has been found that it is very important to ensure that after lacquering, the web is correctly heated because if not, difficulties arise.

Further, the invention provides the printing of the front face of the web which comprises feeding a continuous web of the material on a conveying system comprising at least one driven drum roller and a plurality of idler rollers through a number of workstations comprising the steps of:- delivering the web across two in-line alignment rollers mounted together on a separate pivotal carriage; sensing the position of the edge of the web downstream of the alignment rollers by delivering a portion of a constant jet of air against one face of the web adjacent its edge; collecting the air transmitted across the web; measuring the amount of air collected as an indication of the edge position of the web; causing pivotal movement of the carriage in response to the edge position sensed; leading the web to a printing station; applying printing ink onto a front face of the web by leading the web between two vertically arranged nipping rollers, the lower roller forming a printing roller being partially submerged in an ink retaining bath and applying a scraping blade against the lower nipping roller to remove excess ink; heating the front face of the web; and delivering air onto the front face of the web to dry and cool it.

After once printing the front face of the web, the front face is again printed using a patterned roller to produce a mottled effect. ldeally, the heating of the web after printing is carried out at a temperature within the range 60 to 80‘-‘C and preferably this can be within the range 65 to 75‘—’C.

When applying printing ink, the method comprises using a roller of an elastic material to form the upper nipping roller and providing an additional idler roller of a rigid material to contact the upper nipping roller to prevent it flexing. ideally, prior to printing on the front face of the web, a flame retardant material is applied to the rear face.

It has been found advantageous that when applying lacquer, the scraping blade subtends an angle of approximately 559 with the web.

The web is fed at the rate of between 8 and 12 meters per minute but may be fed at a rate of between 9 and 11 meters per minute.

Further, the invention provides a method comprising the steps of:- delivering the rolled web of embossed PVC coated fabric material to an unrolling station; placing a core on the web adjacent a free end thereof; rotating the core and web to wrap some of the web around the core; tipping the rolled core away from the rolled web to allow a length of web to be exposed; placing adhesive tape on the web intermediate the rolled core and the rolled web; cutting the web to leave the adhesive tape on the web on the core; placing a thermoplastics sheet wider than the web onto the web in contact with the adhesive; re-rolling the web and the sheet until the sheet completely surrounds the web and core; and heat sealing the thermoplastics sheet to itself to cut the sheet and to encompass the web on the core.

Ideally, the heat shrinking occurs at between 100 to 13090.

E .| In .|. "I I I.

The invention will be more clearly understood from the following description of an embodiment thereof, given by way of example only, with reference to the accompanying drawings, in which:- Fig. 1 is a side view of embossing plant according to the invention, Fig. 2 is an enlarged view of an embossing station forming part of the embossing plant, Fig. 3 is a side view of a combined lacquering and printing machine, Fig. 4 is a perspective view of portion of a printing station, Fig. 5 is a side view of the printing station, Fig. 6 is a perspective view of an alignment station, Fig. 7 is a perspective view of the alignment station with the web removed, Fig. 8 is a perspective view of portion of a lacquering station, Fig. 9 is a side view of the lacquering station, Fig. 10 is a side view of a packing machine, Figs. 11 and 12 are enlarged views of an infeed station forming part of the packaging machine, Fig. 13 is an enlarged view of the infeed station and the gluing and cutting station forming part of the packing machine, Figs. 14 to 19(a) to (j) are enlarged side views of shrink wrapping and take-oft stations forming part of the packing machine, and Fig. 20 is a diagrammatic view showing operation of the packing machine.

Referring to the drawings and initially to Figs. 1 and 2, there is provided an embossing plant, indicated generally by the reference numeral 1 comprising an infeed station 2, embossing station 3, cooling station 4 and draw-off station 5, through which painted but unlacquered PVC coated fabric material is fed through. in this description, the PVC coated fabric material is in the form of a web and is identified by the reference numeral 6, its front face being identified by the reference numeral 7 and its rear face by the reference numeral 8, irrespective of whether it is printed, lacquered or not. Idler rollers are throughout identified by the reference numeral 9.

The infeed station 2 comprises a support 10 for carrying a roll of web 6 which in turn feeds an accumulator 11 which allows the web to be flaked out thereon. The accumulator 11 in turn feeds the embossing station 3.

Referring to Fig. 2, the embossing station 3 comprises an enlarged hollow heating drum 15 fed by a feed pipe 16 and a return pipe 17 by a boiler 18 with hot oil. The web 6 is fed through various rollers 9 to the hollow heating drum 15 where it is then led through infrared heating lamps 20 to embossing rollers, namely, an embossing roller 21 and an embossing roller 22. The embossing roller 21 is a patterned roller of hardened steel having the required pattern. The roller 22 is a soft rubber roller relatively elastic which is in turn driven by a metal drive roller 23. The cooling station 4 comprises a plurality of further rollers 9 which in turn feed three water cooled rollers 24 which are hollow and are fed with cooling water by a pump (not shown). The draw-off station 5 comprises a plurality of rollers arranged to stretch and further cool the web 6.

In use, a roll of PVC coated fabric material which will have already been printed but not lacquered is placed on the support 10 and is drawn through the embossing plant. When the web arrives at the embossing station 3, the web is heated to between 170 and 1809C before it is embossed. After embossing, it is led through the cooling station 4 and on exiting the cooling station 4 to the draw-off station 5, it is stretched further and is then rolled at 26. The web is generally drawn through the embossing station at a speed of about 10 m per minute. This can vary from between 8 to 12 m per minute. After embossing, the embossed PVC web has to be lacquered. Many other suitable heating fluids such as steam may be used.

Referring now to Fig. 3, there is provided a combined lacquering and printing machine, indicated generally by the reference numeral 30 comprising from right to left, an outfeed station 31, an infeed station 32, a printing station 33, an alignment station 34, further printing stations 33 and a lacquering station 35, above all of which is mounted an oven 36. For ease of understanding, it is better to describe the whole printing and lacquering machine 30. Starting at the infeed station 32, there is provided a holder 40 for a web, again identified by the reference numeral 6 and again all idler rollers are identified by the reference numeral 9. The web 6 is then led into the first printing station 33.

Referring to Figs. 4 and 5, each printing station 5 comprises a pair of nipping rollers, namely, an upper nipping roller 40 and a lower nipping roller 41, partially submerged in an ink retaining bath 42. The upper nipping roller 40 is manufactured from rubber and is secured in position and retained by a solid further additional idler roller 43. A scraper blade 45 is mounted against a lower nipping roller 41 to ensure that a constant film of ink is taken up by the nipping roller 41. The web is then led to the alignment station 34.

Referring now to Figs. 6 and 7, the alignment station 4 comprises a support framework 55 carrying a pivot mounting 56 on which is mounted a sub-frame 57 which in turn carries a pair of alignment rollers 58. A pneumatic ram 59 is provided for pivoting the sub-frame 57 about the pivot mounting 56 and thus for alignment of the web 6. Mounted below the support framework 55 by a cantilevered support 61 is a sensor 62 having a bifurcated arm 63. One bifurcated arm 63 carries a nozzle (not shown) for the delivery of a jet of air against the edge of the web 6, while the other arm carries a cup-like receiver for the reception of any air delivered across the edge of the web. Control means are provided within the sensor 62 for measuring the amount of air collected and thus the position of the edge of the web. The sensor 62 is connected by suitable control means to operate the pneumatic ram 59. Then, there are further printing stations 5 of substantially the same construction as ._lO_ described above. Finally, the Iacquering station 35 comprises an upper Iacquering roller 60 having a plurality of upwardly arranged projections 61 to grip the web 6 therebetween it and a lower printing roller 62 partially submerged within a bath of lacquer 63. A scraper blade 64 is mounted in contact with the web 6 and is sited above the lacquer bath 63. Then, from out of the heating oven 36, the web is led back and forth by idler rollers 9 and then out to the outfeed station 31 which has a driven roller 80 for take up of the web.

In operation, when the web 6 has been embossed, the web 6 is placed in the infeed station 32 and is led through the printing stations 33 and alignment stations 34 without any printing being carried out until it is delivered to the Iacquering station 35 where lacquer is applied. Then, the web 6 is led through the oven 36 to fix the lacquer on the printed and embossed web 6. The web 6 is then led back and forth beneath the oven to cool it before it is led to the outfeed station 31.

When it is desired to print the web 6 prior to embossing and Iacquering, then the web is delivered to the infeed station 40 and at the first printing station 33, the back of the web is printed with a flame retardant material and any indicia or other identification marks required are then printed on the web. The web 6 is then led through to the second printing station 33 where, depending on the amount of painting required, one or two coats of the same or different coloured ink is applied. Because, in many instances, a mottled effect will be required, it is not unusual to bring a partially painted web through the first painting station 33 without painting or printing any flame retardant material thereon and then going to the second printing station where a mottled effect can be printed on the web by using a patterned roller. When the web is printed in this way, it is then led to the Iacquering station which is bypassed and then through the oven 36 to fix the printed web which is then brought to the embossing plant for subsequent embossing.

Referring to Figs. 10 and 20 inclusive, there is illustrated a packing machine indicated generally by the reference numeral 100 comprising an infeed station 101, a control station 102, a rolling station 103, a gluing and cutting station 104, a shrink wrapping station 105 and a take-off station 106. The infeed station 101 comprises a web roll support 110 and incorporates again idler rollers 9 mounted on a framework 111 _ll_ pivotally mounted on a support 112 and movable thereon by a ram (not shown). The web 6 is led from the infeed station 101 beneath the control station 102 which comprises a computer 115 connected to various portions of the packing machine 100. The web 6 is led underneath the control station 102 to the rolling station 103.

The rolling station 103 (see Fig. 11) comprises a magazine 120 mounted by means of uprights 121 above a support table 122. Also mounted on the support table 122 are idler rollers 123 and 124. Means are provided to pivot the idler rollers 123 and 124 so that the idler roller 123 lies above the idler roller 124. This means is not shown. The magazine mounts core dispensing arms 125 and a roller actuator 126 is pivotal about an arm 127. All the pivoting is done by means of pneumatic rams (not shown).

The gluing and cutting station 104 (see Fig. 13) comprises a adhesive tape dispensing head 130 mounted above the support table 122 and reciprocal transversely thereon. A cutter blade 131 is also mounted above the support table 122 and again reciprocal transversely thereon. A pair of idler rollers 132 and 133 are mounted on the support table 122 and are again pivotal such that the idler roller 132 can pivot relative to the idler roller 123 so as to raise the idler roller 132 above the idler roller 133. This is done by means of pneumatic rams (not shown).

Referring specifically to Figs. 14 to 19, the shrink wrapping station 105 comprises a support framework 140 above the support table 122 carrying a heat sealing mechanism 141 raised up and down on the support framework 140 by a motor 142.

The heat sealing mechanism incorporates hot air end sealers 143 and a transverse heat sealing bar 144, all of convention construction. Mounted below the heat sealing mechanism 141 is a reel support 145 carrying plastics film material 146. A pivotal end stop 147 is provided beneath the heat sealing mechanism 141 as is a drive roller 148. Various end sensors for sensing the end of the web 6 are provided but are not illustrated.

Again referring to Figs. 14 to 19 inclusive, the take-off station 106 comprises a support 150 mounting a pivoting chute 151 and a pivotal cradle 152 actuated by a ram 153. in operation and referring specifically to Fig. 20, a web roll is placed on the web roll support 110 and the framework 111 is pivoted sufficiently to provide a suitable tension on the web 6. The web 6 is led initially, when the first web is placed on the packing machine 100, through the various idler rollers 9 to the rollers 123 and 124 where a small amount of the web 6 is pulled between these rollers. Then the core dispensing arms 125 carrying one core identified by the reference numeral 128 is lowered onto the web 6. Then, the core dispensing arms 125 are retracted and the roller actuator 126 is pivoted about the arm 127. The roller actuator 126 then rolls the web 6 about the core 128 (see Figs. 20(b)) until the requisite amount of web 6 has been wrapped around the core 128. Then, the roller actuators 126 are stopped and retracted. The roller 123 is then pivoted upwards which causes the core 128 carrying the rolled up web 6 to pivot away from the rollers 123 and 124 to assume the position above the two rollers 132 and 133 as illustrated in Fig. 20(c). Then, the adhesive tape dispensing head 130 is operated to place tape on the exposed length of web and then the cutter blade 131 is used to cut the web. The web 6 is then, together with the core 128, again tipped by the roller 132 towards the shrink wrapping station 105 where it is then tipped against the pivotal end stop 147 where it is rolled up until most of the free end of the web 6 has been rolled. Then the plastics film material 146 is dispensed across the web to adhere thereto (Fig. 20(f)). it is then rolled around further until sufficient plastics film material 146 is wrapped around the core and web.

Then, the heat sealing mechanism is lowered and then plastics film is heat sealed to itself and cut-off. Then, the two ends are heat sealed and the web is totally wrapped, as can be seen in Fig. 20. Then, the pivotal end stop 147 is pivoted downwards and the rolled web is delivered onto the pivotal chute 151 (see Fig. 16). Then the pivotal chute 151 is pivoted (see Fig. 16 and 17) to cause the rolled web to be deposited in the pivotal cradle 152 (see Fig. 18). Then, the pivotal cradle is pivoted downwards as illustrated in Fig. 19.

In the specification the terms "comprise, comprises, comprised and comprising" or any variation thereof and the terms "include, includes, included and including" or any variation thereof are considered to be totally interchangeable and they should all be afforded the widest possible interpretation.

The invention is not limited to the embodiments hereinbefore described but may be varied in both construction and detail.

Claims (1)

1. A method of embossing a PVC coated fabric material comprising: initially printing a front face of a continuous web of the material; and then feeding the web on a conveying system comprising at least one drive drum and a plurality of idler rollers through a number of workstations and carrying out the steps of:- delivering the web from a roll through an accumulator; leading the web around most of the outer periphery of an enlarged heater drum to preheat the web by passing hot fluid through the interior of the drum; applying infrared heat to the front face of the web as it exits the heater drum to heat the web to a final temperature of between 160‘-’C to 19090; leading the web through a pair of hollow rollers, namely a hardened steel patterned embossing roller and a nipping roller, the nipping roller being of an elastic material to apply a pressure against the web, driving the nipping roller by a diametrically opposed steel drive roller, exerting a pressure on the nipping roller by the drive roller to exert a constant contact pressure on the web across it’s width, simultaneously delivering cooling water through the hollow rollers as the web is being embossed, leading the web through a further set of hollow idler rollers, simultaneously delivering cooling water through the idler rollers as the embossed web is being led therethrough; stretching the web as it exits the embossing rollers by leading the web through further rollers; and Iacquering the front face of the web by:- delivering the web across two in-line alignment rollers mounted together on a separate pivotal carriage; sensing the position of the edge of the web downstream of the alignment rollers by delivering portion of a constant jet of air against one face of the web adjacent its edge; collecting the air transmitted across the web; measuring the amount of air collected as an indication of the edge position of the web; causing pivotal movement of the carriage in response to the edge position sensed; leading the web to a lacquering station; applying lacquer to the front face of the web by leading the web between two rollers, one of which is a lacquer applying roller being partially submerged in a lacquer containing bath for the take up of lacquer thereon and then scraping excess lacquer from the face of the web; heating the front face of the web to a temperature between 8590 and 11590 to cure the lacquer; and cooling the web after lacquering. A method as claimed in claim 1, in which the web is heated to between 1709C and 1809 prior to embossing. A method as claimed in claim 1 or 2, in which the heating fluid is one of steam and hot oil. A method as claimed in any preceding claim, in which the heating of the web after Iacquering is carried out at approximately 10090. A method as claimed in any preceding claim, in which the printing of the front face of the web comprises feeding a continuous web of the material on a conveying system comprising at least one driven drum roller and a plurality of idler rollers through a number of workstations comprising the steps of:- delivering the web across two in-line alignment rollers mounted together on a separate pivotal carriage; sensing the position of the edge of the web downstream of the alignment rollers by delivering a portion of a constant jet of air against one face of the web adjacent its edge; collecting the air transmitted across the web; measuring the amount of air collected as an indication of the edge position of the web; causing pivotal movement of the carriage in response to the edge position sensed; leading the web to a printing station; applying printing ink onto a front face of the web by leading the web between two vertically arranged nipping rollers, the lower roller forming a printing roller being partially submerged in an ink retaining bath and applying a scraping blade against the lower nipping roller to remove excess ink; heating the front face of the web; and delivering air onto the front face of the web to dry and cool it. A method as claimed in claim 5, in which after once printing the front face of the web, the front face is again printed using a patterned roller to produce a mottled effect. A method as claimed in claim 5 or 6, in which the heating of the web after printing is carried out at a temperature within the range 60 to 8090. A method as claimed in claim 5 or 6 in which the heating of the web after printing is carried out at a temperature within the range 65 to 7590. A method as claimed in any of claims 5 to 8 in which, when applying printing ink, the method comprises using a roller of an elastic material to form the upper nipping roller and providing an additional idler roller of a rigid material to contact the upper nipping roller to prevent it flexing. A method as claimed in any of claims 5 to 9, in which prior to printing on the front face of the web, a flame retardant material is applied to the rear face. A method as claimed in any preceding claim, in which when applying lacquer, the scraping blade subtends an angle of approximately 559 with the web. A method as claimed in any preceding claim in which the web is fed at the rate of between 8 and 12 meters per minute. A method as claimed in any of claims 1 to 14, in which the web is fed at the rate of between 9 to 11 meters per minute. A method as claimed in any preceding claim comprising:- delivering the rolled web of embossed PVC coated fabric material to an unrolling station; placing a core on the web adjacent a free end thereof; rotating the core and web to wrap some of the web around the core; tipping the rolled core away from the rolled web to allow a length of web to be exposed; placing adhesive tape on the web intermediate the rolled core and the rolled web; cutting the web to leave the adhesive tape on the web on the core; placing a thermoplastics sheet wider than the web onto the web in contact with the adhesive; re-rolling the web and the sheet until the sheet completely surrounds the web and core; and heat sealing the thermoplastics sheet to itself to cut the sheet and to encompass the web on the core. A method as claimed in claim 17, in which the heat shrinking occurs at between 100 to 13090. A method substantially as hereinbefore described with reference to the accompanying drawings. An embossed printed PVC coated fabric material produced in accordance with the method of any of preceding claim.