CLAIMS:
1. A method of manufacturing sheeting of synthetic polymeric material, the method including continuously passing a rigid endless moulding surface past an applicator station, a curing section and a stripping station, all arranged in series proximate a path of the endless moulding surface; at the applicator station, applying synthetic polymeric material in mouldable form in a layer on the moulding surface; causing the synthetic polymeric material to set; in the curing section, curing the layer of synthetic polymeric material; at the stripping station, stripping the set and cured layer of synthetic polymeric material in the form of sheeting off the moulding surface.
2. A method as claimed in Claim 1 in which said moulding surface is a periphery of a rotor, and passing the moulding surface past the respective stations and section is by rotating the rotor about a fixed axis.
3. A method as claimed in Claim 2 in which rotating the rotor is by propelling it in a predetermined direction by means of a peripheral drive acting on a peripheral rim of the rotor.
4. A method as claimed in any one of Claim 1 to Claim 3, in which applying the synthetic polymeric material is by means of at least one of at least one spray spraying the material onto said surface; passing said surface through a bath containing the material in fluid form; a doctor blade spreading the material in flowable form across said surface.
5. A method as claimed in any one of the preceeding Claims, including introducing reinforcing material into the layer of synthetic polymeric material prior to curing and setting.
6. A method as claimed in Claim 5 in which said introducing of reinforcing material is effected at a reinforcing station by means of dynamic applicators.
7. A method as claimed in Claim 6 which includes introducing at least some of resin, catalyst and curing agent into the synthetic polymeric material at the applicator station.
8. A method as claimed in claim 6 which includes introducing at least some of resin, catalyst and curing agent into the synthetic polymeric material together with the reinforcing material at the reinforcing station.
9. A method as claimed in any one of the preceeding Claims including covering the moulding surface by means of a replaceable layer having a predetermined texture and imparting to the corresponding surface of the sheeting a corresponding texture.
10. A method as claimed in any one of the preceeding Claims, including applying a covering film having a predetermined texture, downstream of the applicator section and upstream of the curing section over the synthetic polymeric material to impart a corresponding texture to the corresponding side of the sheeting.
11. A method as claimed in any one of the preceeding Claims, including trimming and finishing the formed sheeting, preferably upstream of or in conjunction with stripping of the sheeting off the rotor, along edges by means of a pair of edge cutters to trim the sheeting to a preferred width.
12. Manufacturing apparatus for manufacturing sheeting of synthetic polymeric material, the apparatus including a continuous moulding surface of rigid construction; drive means for continuously driving the continuous moulding surface along a predetermined path; an applicator station proximate said path at a relatively upstream position and including one of more sprays for applying synthetic polymeric material in mouldable form onto the moulding surface; a curing section proximate said path spatially downstream of the applicator station and including curing means for curing the synthetic polymeric material; a stripping station proximate said path downstream of the curing station including a stripping device for stripping the cured and set sheeting off the moulding surface.
13. A manufacturing apparatus as claimed in Claim 12 which includes a rotor having a periphery which provides the continuous moulding surface.
14. A manufacturing apparatus as claimed in Claim 13 in which the rotor is round, is rotatable about a fixed axis and has a diameter of at least about 2 metres.
15. A manufacturing apparatus as claimed in Claim 13 and Claim 14 in which the rotor has a peripheral rim in the form of a barrel, a central hub, and a structure supporting the rim about the hub.
16. A manufacturing apparatus as claimed in any one of Claim 13, Claim 14 or Claim 15 in which the drive means is peripheral relative to the rotor and acts on the barrel.
17. A manufacturing apparatus as claimed in any one of Claim 13 to Claim 16, which includes, over the moulding surface, a film or layer of a material having a predetermined texture adapted to impart a corresponding texture to the corresponding surface of the layer of synthetic polymeric material.
18. A manufacturing apparatus as claimed in any one of Claim 13 to Claim 17, which includes means for covering the layer of synthetic polymeric material, downstream of the reinforcing station and upstream of the curing section, with a film of material having a predetermined texture to impart a corresponding texture to a free surface of the synthetic polymeric layer.
19. A manufacturing apparatus as claimed in any one of Claim 12 to Claim 18 which includes a reinforcing station, including an applicator for reinforcing material, proximate the periphery of the rotor intermediate the applicator station and the curing section, for introducing reinforcing material into the layer of synthetic polymeric material in use.
20. A manufacturing apparatus as claimed in Claim 19 which includes an applicator for applying at least some of a resin, catalyst and curing agent, said applicator being at or downstream of the applicator station.
21. A manufacturing apparatus as claimed in Claim 20 in which said applicator is at the reinforcing station to apply said some of the resin, catalyst and curing agent in conjunction with the reinforcing material.
22. A manufacturing apparatus as claimed in any one of Claim 12 to Claim 21 which includes trimming and finishing means, including a pair of edge cutters for trimming the synthetic polymeric layer to a desired width.
23. A manufacturing apparatus as claimed in any one of Claim 12 to Claim 22, which includes a coiling device downstream of the stripping device for coiling the stripped sheeting into coils. |
A METHOD OF AND APPARATUS FOR MANUFACTURING
SHEETING OF SYNTHETIC POLYMERIC MATERIAL
THIS INVENTION relates to the manufacture of sheeting of synthetic polymeric material. It relates more specifically to a method of and apparatus for manufacturing sheeting of synthetic polymeric material.
The Applicant is of opinion that the invention will find application particularly in the manufacture of fibre or glass reinforced synthetic polymeric sheeting, and that application will receive preference for purposes of this specification. The invention, however, is not limited to that application.
In accordance with a first aspect of this invention, there is provided a method of manufacturing sheeting of synthetic polymeric material, the method including continuously passing a rigid endless moulding surface past an applicator station, a curing section and a stripping station, all arranged in series proximate a path of the endless moulding surface; at the applicator station, applying synthetic polymeric material in mouldable form in a layer on the moulding surface; causing the synthetic polymeric material to set; in the curing section, curing the layer of synthetic polymeric material; at the stripping station, stripping the set and cured layer of synthetic polymeric material in the form of sheeting off the moulding surface.
In a preferred method, said moulding surface may be a periphery of a rotor, and passing the moulding surface past the respective stations and section may then be by rotating the rotor about a fixed axis. The rotor is preferably round, such that peripheral points will follow the same path.
Rotating the rotor may be by propelling it in a predetermined direction by means of a peripheral drive acting on a peripheral rim of the rotor. The moulding surface may conveniently be an outer peripheral surface of the rotor. The peripheral drive may then be acting, correspondingly, on an inner periphery, of the rotor. In other methods, driving may be effected in other convenient or advantageous manners.
Applying the synthetic polymeric material may be by means of at least one of at least one spray spraying the material onto said surface; passing said surface through a bath containing the material in fluid form; a doctor blade spreading the material in flowable form across said surface.
The method may include introducing reinforcing material into the layer of synthetic polymeric material prior to curing and setting. Said introducing of reinforcing material may be effected at a reinforcing station by means of dynamic applicators. Reinforcing may be in the form of roving, woven roving, continuous roving, chopped strand mat and of different core materials.
The method may include introducing at least some of resin, catalyst and curing agent into the synthetic polymeric material at the applicator station. Instead, introducing at least some of resin, catalyst and curing agent into the synthetic polymeric material may be together with the reinforcing material at the reinforcing station.
Curing may be by conventional heating or ultra violet radiation or a combination thereof. Conventional heating may be by electrical resistance heating or conduction heating, by coal burners, sunlight, or the like. Heating may be applied from outside, or from inside, or from both outside and inside of the rotor periphery.
The method may include covering the moulding surface by means of a replaceable layer having a predetermined texture and imparting to the corresponding surface of the sheeting a corresponding texture. The texture must be understood to
include a smooth surface as an option. The Applicant prefers a film of MYLAR. The film is re-usable, i.e. it is replaced only periodically.
Instead, or in addition, the method may include applying a covering film having a predetermined texture (including a smooth surface as an option), downstream of the applicator section and upstream of the curing section over the synthetic polymeric material to impart a corresponding texture (including a smooth surface as an option) to the corresponding side of the sheeting. This film may be stripped or guided off prior to stripping of the formed sheeting off the rotor. The film may be handled by means of rollers or as rotatable sleeves and may be re-usable.
The method may include trimming and finishing the formed sheeting, preferably upstream of or in conjunction with stripping of the sheeting off the rotor, along edges by means of a pair of edge cutters to trim the sheeting to a preferred width. Sheeting may also be cut to length by means of a cross cutter.
In accordance with a second aspect of this invention, there is provided manufacturing apparatus for manufacturing sheeting of synthetic polymeric material, the apparatus including a continuous moulding surface of rigid construction; drive means for continuously driving the continuous moulding surface along a predetermined path; an applicator station proximate said path at a relatively upstream position and including one of more sprays for applying synthetic polymeric material in mouldable form onto the moulding surface; a curing section proximate said path spatially downstream of the applicator station and including curing means for curing the synthetic polymeric material; a stripping station proximate said path downstream of the curing station including a stripping device for stripping the cured and set sheeting off the moulding surface.
The manufacturing apparatus preferably includes a rotor having a periphery which provides the continuous moulding surface. The rotor may be round, may be rotatable about a fixed axis and may have a diameter of at least about 2 metres. The fixed axis may be horizontal, the rotor resembling a Ferris Wheel.
The continuous moulding surface may be an outer surface of the rotor. The rotor may have a peripheral rim in the form of a barrel, a central hub, and a structure supporting the rim about the hub. The drive means may be peripheral relative to the rotor and may act on the barrel. It may include an electric motor, which is speed-controllable and it may drive a wheel or roller frictionally in contact with the barrel at a selectable speed.
By way of development, the manufacturing apparatus may include, over the moulding surface, a film or layer of a material having a predetermined texture (including a smooth surface as an option) adapted to impart a corresponding texture to the corresponding surface of the layer of synthetic polymeric material. It may be in the form of a film of MYLAR. The film of MYLAR may be replaceable periodically.
Instead, or in addition, the manufacturing apparatus may include means for covering the layer of synthetic polymeric material, downstream of the reinforcing station and upstream of the curing section, with a film of material having a predetermined texture (including a smooth surface as an option) to impart a corresponding texture to a free surface of the synthetic polymeric layer. The material may be MYLAR. Such film may be handled by means of rollers or as rotatable sleeves and may be re-usable. It may, for example, be in the form of a continuously moving endless belt.
Further, by way of development, the manufacturing apparatus may include a reinforcing station, including an applicator for reinforcing material, proximate the periphery of the rotor intermediate the applicator station and the curing section, for introducing reinforcing material into the layer of synthetic polymeric material in use. The device may be adapted to apply roving, e.g. woven roving, or
continuous roving. Instead, it may be adapted to apply chopped strand mat or the like. If desired, the device may be adapted to apply any one or more of different types of reinforcing.
In a preferred embodiment, the manufacturing apparatus may include an applicator for applying at least some of a resin, catalyst and curing agent, or the like, said applicator being at or downstream of the applicator station. Instead, said applicator may be at the reinforcing station to apply said some of the resin, catalyst and curing agent, or the like, in conjunction with the reinforcing material.
The manufacturing apparatus may include trimming and finishing means, including a pair of edge cutters for trimming the synthetic polymeric layer to a desired width. It may include also a cross cutter for cutting the sheeting to length.
The manufacturing apparatus may include a coiling device downstream of the stripping device for coiling the stripped sheeting into coils.
The invention is now described by way of example with reference to the accompanying diagrammatic drawings. In the drawings
Figure 1 shows a three dimensional view of manufacturing apparatus in accordance with the invention; and
Figures 2, 3 and 4 show respectively an axial view, an end view and a top plan view of the manufacturing apparatus of Figure 1. Figure 2 is amplified to show also fitting, trimming and coiling apparatus not shown in the other drawings.
With reference to the drawings, manufacturing apparatus in accordance with the invention is generally indicated by reference numeral 10. It is to be appreciated that the invention provides a unique configuration formed of components which are generally known per se for the manufacture of synthetic polymeric sheet material. Thus, only the general configuration will be described and not the individual components or subsystems, as they are generally known per se.
The manufacturing apparatus 10 is a rotary apparatus rotatable about a decumbent or horizontal axis 12. It comprises a rotor 14 rotatable about the axis 12, generally in the manner of a Ferris Wheel or mine rope winder. The rotor 14 is conveniently in the order of a couple of metres to several metres in diameter. The rotor 14 has an outer periphery 16 which, in this embodiment, is round having a smooth outer surface. The outer periphery 16 is supported on a hub 18 by means of spokes, a spider, side plates, or whichever way is regarded as appropriate and convenient.
The rotor 14 is surrounded by a platform structure generally indicated by reference numeral 20. The platform structure 20 is, in this embodiment, of steel comprising columns, girders, sets of stairs and platforms to mount the various subsystems around the periphery of the rotor 14.
The rotor 14 is continuously rotatable by means of a rotary drive which, in this embodiment, as seen in the perspective of Figures 1 and 2, is anti-clockwise.
During manufacture of synthetic polymeric sheeting, a layer of synthetic polymeric material is applied to the outer periphery 16 over a smooth, slick substrate which is in the form of a MYLAR film and which is only periodically replaced. As can best be seen from Figure 2, at a position proximate the periphery of the rotor 14, there is provided an applicator station generally indicated by reference numeral 22 which comprises applicators, conveniently in the form of a plurality of sprays by means of which the synthetic polymeric material in mouldable form is applied in the form of a layer to the periphery 16 of the rotor 14.
At a downstream position (bearing in mind the rotation direction) proximate the periphery of the rotor 14, there is provided a reinforcing station generally indicated by reference numeral 24 and comprising a device for applying reinforcing material, for example in the form of roving such as woven roving, continuous roving or chopped strand mat into the layer of synthetic polymeric
material. The reinforcing station 24 further comprises applicators for resin and catalyst or curing agent to be introduced into the layer of synthetic polymeric material.
From the reinforcing station 24, the layer moves toward a curing section generally indicated by reference numeral 26. Upstream of the curing section 26 an outer film or skin of MYLAR is applied over the layer of synthetic polymeric material to impart also to the outer surface a smooth texture. This outer film or skin is reclaimed downstream of the curing section for re-use.
In the curing section 26, the synthetic polymeric layer is cured in any convenient and appropriate fashion, for example by application of heat from conventional sources such as resistance heating, heating by combustible material like coal, heating by sunlight, or by UV radiation or the like.
Downstream of the curing section 26, the set and cured layer of synthetic polymeric material is stripped off the outer periphery 16 and is guided to a coiling station 32 where it is coiled into coils or rolls 34. Figure 2 shows edge cutters 28, and a cross cutter 30 providing trimming and finishing apparatus downstream of the position of stripping the sheeting from the rotor, to reduce the layer of synthetic polymeric material to an even and constant width of desired dimension. The cross cutter 34 is provided to cut lengths off the layer after coiling.
It is to be appreciated that operation of the manufacturing apparatus 10 is automatic or semi-automatic. Thus, for example, rotation of the rotor 14 is by means of programmable logic circuit control which is programmed bearing in mind a particular application. Likewise, application of synthetic polymeric material at the applicator station 22 and application of reinforcing material, resin, catalyst and curing agent at the reinforcing station 24 are also under programmable logic circuit control. Also curing in the curing section 26 is preferably automatically controlled.
It is an advantage that sheeting of synthetic polymeric material is continuously manufactured under programmable logic circuit control thus promoting consistent quality, that manufacturing takes place in a compact area and that movement of the layer of synthetic polymeric material is mechanically easy in a manner which is easily controlled i.e. via the rotor 14.
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