WO2016144199A1

WO2016144199A1 - Thermal insulation with cellular structure and a set of devices for producing thermal insulation with cellular structure

Info

Publication number: WO2016144199A1
Application number: PCT/PL2016/000027
Authority: WO
Inventors: Piotr CHUPTYŚ
Original assignee: Allsetpro Spółka Z Ograniczoną Odpowiedzialnością
Priority date: 2015-03-09
Filing date: 2016-03-08
Publication date: 2016-09-15
Also published as: PL411520A1

Abstract

The subject of the invention is a thermal insulation with cellular structure comprising at least two layers of film made of a polymer, preferably polyethylene, joined with each other by means of welding method, of which one layer has fully flat surface and the other is provided with profiled hollows called commonly bubbles in the whole of its surface, or produced in the form of boards of polymer foam with cellular structure filled up with a gas characterised in that the profiled hollows (17) made in layer (15) are entirely filled up with gas (8) with density higher than the density of air under atmospheric pressure, such gas being specifically argon, whereas the hollows are filled up with said gas up to 0.5% to 100% of their volumes. On the other hand, the board-shaped form of thermal insulation according to the invention has closed cells filled up with argon. The essential idea behind the concept of producing thermal insulation with cellular structure according to the invention consists in that all technological operations connected with fabrication of finished product in the form of thermal insulation are carried out in argon atmosphere.

Description

Thermal insulation with cellular structure and a set of devices for producing thermal insulation with cellular structure

The subject of the invention is a thermal insulation with cellular structure and a set of devices for producing thermal insulation with cellular structure, especially in the form of bubble film, having its application as thermal insulation of central heating airborne supported pipelines and used to wrap or shield pipes conveying hot water, industrial liquids, and other media, as well as in the form of board-shaped foam elements used in component devices of cooling/ refrigerating systems and in the building industry.

Known are bubble films called also blister films, produced out of two thin layers of polyethylene film joined with each other by means of welding method, where one film layer is flat and the second has hollows pressed therein in the form of cylinders terminated with spherical cap distributed a regular distance from each other. Diameters of these hollows range usually from 6 mm to 25 mm, and their heights from 4 mm do 7 mm, whereas each of the hollows contains air under atmospheric pressure.

The known method of producing bubble films consists in that in the first stage of the method, produced are two layers of thin polyethylene film by means of heating granulated polyethylene up to temperature higher than its melting point, i.e. from 150°C to 160°C placed in a cylinder provided with piston, and extruding a band of film from said cylinder through two slit nozzles situated parallel to each other and connected with said cylinder. Next, in the second stage of the method, one layer of the film is heated up and moved over surface of a rotating drum provided with holes symmetrically distributed over its surface. As air is suck out from inside of the drum, the air under atmospheric pressure present outside presses fragments of the film down inside the drum and produces substantially cylindrical hollows in the film distributed regularly on its surface. In the further stage of the method of producing the bubble film, both film layers, i.e. this with flat surface and this with surface provided with hollows, are conveyed one over the other and joined with each other by means of welding method, whereas welding occurs only on the portions of film surfaces which are situated between the pressed hollows, and as both film layers are continuously in atmospheric air, the hollows are being sealed together with air remaining in them under atmospheric pressure.

Polish patent application No. P-393892 reveals a multilayer thermally insulating material which is a bubble film comprising at least two layers of polyethylene film, whereas at least one of them has sealed hollows filled with gas and further has at least one layer in contact with the side with bubbles, which is coated with a metal, preferably aluminium. The bubble film produced this way finds application in thermal insulation of buildings and other structures by means of attaching it to their surfaces Also Japanese patent description JP8025475 (Al) discloses a film made of polyethylene, polystyrene, or polyvinyl chloride and a method of producing such film, in a course of which to fill up the film, gases with density lower that the density of air under atmospheric pressure are used, such as e.g. hydrogen, helium, nitrogen, or methane.

Further, Polish patent description No. PL218151B 1 teaches a bubble film and a method of producing such film which finds its application in construction of statodynes, i.e. heavier-than-air aircraft, and in packing of any object in order to protect them against mechanical damage and reduce their weight, as well as to protect flying objects against their detection by means of radar. The bubble film according to the invention comprises two layers of polyethylene film, of which one is flat and the other is provided with hollows filled with a gas with density lower than the density of air in normal conditions, e.g. with helium, and further the film has a coating on inner surfaces of its cubical hollows in the form of a reinforcing layer made of graphene. As far as the method of producing the bubble film according to the invention is concerned, it consists in that the layer of film made of low density (LD) polyethylene is being spread on upper surface of a steel plate coated with a layer of polytetrafluoroethylene (PTFE) and constituting a die in the form of cover closing the top of an airtight cuboidal box. The die has cube-shaped hollows distributed regularly over its whole surface. Bottoms of hollows have holes with small diameter. Next, air is suck off from the box and from hollows covered with the film via said holes in their bottoms, and upper surface of the film is subject to a stream of hot air at temperature 180°C under atmospheric pressure blown onto the surface for a period of 15 s. Then, air is let into the box until the pressure reaches the value equalling this of the surrounding atmosphere and top surface of the film is covered with a grate made of a PTFE plate and provided with square holes distributed regularly over the whole surface in the same way as the hollows in the lower plate in such a way that the holes in the grate are situated precisely over said hollows. In the subsequent stage, the box together with the film and the plate is placed horizontally in a vacuum chamber, and next to the box, a second layer of polyethylene film, the same as the layer used to produce hollows is placed, whereas this second layer is spread horizontally of a steel plate coated with a layer of PTFE and further covered with a PTFE grate identical to this put onto the layer of film with hollows. A crucible with graphene and an electron gun installed over it are installed in upper portion of the vacuum chamber. Next, pressure in the chamber is reduced to 5.33 x lO^-5 hPa and the temperature increased up to 150°C. High voltage with magnitude of +15 kV modulated to depth of 20% with frequency 5 kHz is then applied to the two layers of polyethylene film and the electron gun is activated. As a result of bombarding graphene with a beam of electrons, the material is subject to atomisation and ionisation and ionised atoms are deposited on uncovered surfaces of both polyethylene film layers for a period of 5-30 s, at electron gun current intensity of 150 mA. In the next stage, temperature in the chamber is brought to ambient temperature level and both polyethylene film layers are removed from the chamber, and then, both layers are introduced via an air lock to an airtight chamber containing helium under normal conditions. The layer of polyethylene film without hollows is then spread, with deposited graphene up, on horizontal bottom of the chamber and covered with the layer of polyethylene film provided with hollows, with openings of said hollows oriented downwards. Position of the upper film is adjusted in such a way that openings of the hollows cover precisely the areas with deposited graphene. Next, the two film layers are welded together at temperature 200°C for 2.5 s along all lines between and outside the 100 hollows by means of a linear heater coated with PTFE. The obtained product is then removed from the chamber filled with helium via an air lock.

The objective of the invention is to provide a thermal insulation with cellular structure, especially of bubble film type, with low heat 105 conductivity designed to be used as insulation and thermal insulation material.

According to the invention, thermal insulation with cellular structure having at least two layers of film extruded from a polymer, preferably polyethylene, joined with each other by means of welding method, of

110 which one has a completely flat surface, and the other has profiled hollows in the form of bubbles symmetrically distributed over its surface, or produced in the form of boards of polymer foam with cellular structure filled up with a gas is characterised in that said profiled hollows made in the film layer are entirely filled up with gas density of which is higher

115 than the density of air under atmospheric pressure, such gas being specifically argon, whereas the hollows are filled up with said gas up to 0.5% to 100% of their volumes, whereas the board-shaped form of the insulation produced by means of foaming method has closed cells also filled with argon.

120 Further, the method of producing thermal insulation with cellular structure consisting in producing it from intermediate products in the form of at least two layers of polymer film subject to further processing resulting in production of a finished product in the form of film band consisting in making profiled hollows commonly called bubbles in one of

125 the films and joining the two films by means of welding method, or consisting in producing it from intermediate product in the form of granulated polymer subject to further processing also aimed at producing a ready-to-use intermediate product in the form of film band consisting in producing out of it a first film layer flat on both surfaces and the second

130 film layer with profiled hollows made in it and joining the two film layers by means of welding method, or consisting in producing such insulation form a granulated polymer and foaming agents by means of the foaming method for the purpose of obtaining a finished product in the form of foamed boards with closed cellular structure is characterised in that all the

135 above-described technological operations connected with fabrication of the finished product in the form of thermal insulation are carried out in argon atmosphere by suitable devices entirely immersed in argon constant level "P" of which is maintained by means of a system of sensors.

The essential idea behind the concept of the set of devices for

140 producing thermal insulation with cellular structure, especially of bubble wrap film type, comprising known device for producing bubble film filled with gas according to the invention consists in that the set comprises a magazine of intermediate products in the form of flat thin bands of polymer film or a magazine containing a stock of intermediate products in

145 the form of polyethylene granules, or a magazine containing a stock of polystyrene granules stored and means used to foam them, said magazines being connected, via their dispensing devices, with a housing or chamber in which the following are installed: a device for producing bubble film by means of welding method, immersed entirely in argon up to level "P",

150 or a device for producing, from the supplied granulated polymer, two thin layers of polymer film, including one with profiled hollows and the other with flat surface, and for joining said two films with each other by means of welding method, or a device producing board-shaped elements form foamed granules, whereas lower ends of the segments, the housings, and

155 the chambers are connected by means of conduits with argon reservoir equipped with a control system which further, via said conduits, is connected with a set of sensors detecting level "P" of argon in which the above-described respective device is immersed.

The use of argon which is a noble gas with heat conductivity

160 equalling 0.01772 W/(rrrK), i.e. much lower than this of atmospheric air, for filling blisters or bubbles in film with cellular structure or pores in board-shaped foam elements according to the invention allows to achieve the objective set for the invention.

The subject of the invention is explained in more detail by means of

165 its example embodiment shown in drawings, of which Fig. 1 shows a schematic block diagram of devices for producing thermal insulation of bubble structure from two separate flat layers of thin polyethylene film; Fig. 2— a schematic block diagram of the set of devices for producing thermal insulation with bubble structure from supplied granulated

170 polyethylene; Fig. 3— a schematic view of the finished product in the form of thermal insulation with cellular bubble-like structure in vertical cross-section; and Fig. 4— a schematic block diagram of the set of devices for producing foamed boards from polystyrene pellets and foaming agents supplied to the set. 175 Example 1

A set of devices for producing thermal insulation in the form of bubble film as shown in Fig. 1 comprises a magazine 1 containing stored ready-to-use intermediate products in the form of flat bands of thin polyethylene (PE) film and connected via the intermediate product

180 dispensing device 2 and a first segment 3 of three-segment housing 4 with typical device 5, for instance one produced by Italian firm Tominera, placed and installed on bottom 6 of the middle segment 7 willed with argon 8 up to level "P" so that the device is entirely immersed with argon, height "H" of which measured from upper surface of the device to

185 constant level "P" was 25 cm, whereas the lower end of the middle segment 7 is connected by means of conduit 9 with reservoir 10 of argon 8, said reservoir being equipped with control system 11 which in turn via conduit 12 is connected with set of sensors 13 controlling level "P" of argon 8 and mounted in lower portion of the segment and partly over the

190 constant level 'T" of argon 8.

Further, the device 5 producing bubble film 16 from two separate bands (layers) of polyethylene film 14 and 15 with bubbles 17 of said film filled in 100% (i.e. entirely) with argon 8, is coupled with magazine 19 of finished final product by means of the device transporting said product

195 which in this case is belt conveyor 18.

The typical device 5 is used to employed to produce bubble film from two separate thin film bands made of a polymer by pressing profiled hollows in one of the films and joining the two films by means of welding method as a result of which the hollows are filled up with air.

200 Example 2

In the second example embodiment of the set of devices for production of thermal insulation in the form of bubble film according to the invention or thermal insulation with profiled chambers as shown in Fig. 2, the set comprises the same devices as those described in Example 1

205 and connected functionally with each other in the same way, with the difference between them consisting in that in the second embodiment, the set comprises magazine 20 containing a stock of ready-to-use intermediate products in the form of polyethylene granules, which, via dispensing device 2 and the first segment 3 of three-segment housing 4 is connected

210 with typical device 21 model FY-Q015005 of Chinese company Zhongshan Fengyuan Plastic Machinery Products Co. Ltd for producing bubble film from granulated polymer, introduced into and installed on bottom 6 of middle segment 7 also filled with argon 8 up to level "P" so that the device is entirely immersed in said argon height "H" of which

215 measured from upper surface of the device to constant level "P" was 30 cm. Lower end of the middle segment 7 of housing 4 is also connected by means of conduit 9 with reservoir 10 for argon 8, said reservoir being equipped with control system 1 1 and further, via conduit 12, is connected with a set of sensors 13 monitoring level "P" of argon 8 mounted in lower

220 portion of the middle segment and partly over the constant level "P" of argon 8. Further, device 21 transforming polyethylene (PE) granules supplied to it into two-layer bubble film 16 with bubbles 17 filled up with argon in 80% and with 20% with atmospheric air is coupled with magazine 19 of the main finished product by means of transporting device

225 18. Typical device 21 employed in this set is used to transform granulated polymer supplied to it into two thin layers of polymer film, one of which is provided with profiled hollows (bubbles) and the other has flat surfaces, and to join the films with each other by means of welding method in the ambient air atmosphere as a result of which the hollows are being filled up

230 with said air.

Example 3

In the third example embodiment of the set of devices for fabrication of thermal insulation in the form of bubble film according to the invention, not shown in drawings, a set of devices employed was the same

235 as this presented in Example 1 with the difference consisting in that the set comprises housing 4 with only one segment filled up with argon 8 up to level "P" along the whole of its length, and the thermal insulation in the form of bubble film was produced with the use of two thin high impact polystyrene (HIPS) layers.

240 Example 4

In the subsequent fourth example embodiment of the set of devices for fabrication of thermal insulation in the form of bubble film, dispensing devices 2 supplied the device 5 producing bubble film immersed entirely in argon atmosphere with three thin layers/bands of polypropylene (PP) or 245 polytetrafluoroethylene (PTFE) or polyamide (PA) or polyurethane (PUR) or polyvinyl chloride (PVC) film.

The principle of operation of devices described in Examples 1 and 2 as embodiments of the invention consists in that magazine 1 or 20 of ready-to-use intermediate products in the form of thin polyethylene film 250 bands or granulated polyethylene are supplied by means of dispensing device 2 to the first segment 3 of three-segment housing 4, and then to device 5 or 21 immersed entirely in atmosphere of argon 8 with specific gravity higher than this of atmospheric air present above it, installed in middle segment 7 of the housing with controlled atmosphere, in which the

255 bubble film is produced out of the two bands of film with the use of any known method, whereas bubbles of the bubble film are filled with argon 8 in 100% or 80%. The bubble film produced in these devices, via the third connecting segment 3 ' of housing 4, is supplied by means of transporting device 18 coupled mechanically with storage 19 of the finished product,

260 whereas during the transport, in the connecting segment 3' the product is entirely cleared gravitationally from argon which, being a gas heavier than air, is turned back to middle chamber 7 of housing 4. Constant level "P" of argon in middle chamber 7 is maintained by means of a set of sensors 13 and a control system 11 which tops up argon 8 from tank 10 to the

265 chamber by means of conduit 9.

Thermal insulation with cellular structure produced with the use of method described above and with the use of the set of devices for production of said insulation constituting the finished final product comprised two polyethylene film layers 14 and 15 joined with each other

270 by means of welding with bubbles 17 entirely filled up with argon 8.

Example 5

The set of devices for producing thermal insulation in the form of porous rigid plate-shaped elements with closed pores as shown in Fig. 4 comprises a storage 22 for granulated polystyrene and means used to foam

275 them, said storage being connected, via the granulated polystyrene dispensing device 23, with controlled-atmosphere chamber 24 filled with argon 8 up to level "P", in which typical known multifunctional device (production line) 25 is mounted, preferably the device known as the continuous pre-expander type EXP-05 or type EXP-1 produced by Polish

280 company Yetico S.A., whereas the chamber is connected by means of conduit 26 with reservoir 27 containing argon 8 and provided with control system 28, connected by means of conduit 29 with chamber 24 which in turn is connected by means of conveyor 30 transporting finished product in the form of board-shaped elements with thickness exceeding 3 mm with

285 storage 31 of said elements. The known multifunctional device 25 installed in chamber 24 is equipped with (not shown in the drawings): storage tanks for dispensing polymer granules, e.g. polystyrene pellets, supplied to them by dispensing device 23 together with chemical of 00027 physical means for foaming said granules; agitators; and a machine for 290 fonning/extruding board-shaped elements with perforated surfaces.

Rigid polyurethane foams produced with this device have low heat conductivity, high compressive strength, high sound absorption coefficient, and high resistance to elevated temperature in the range from -50°C to +120°C. Depending on conditions, they contain from 50% to 295 90%) of closed cells filled entirely with argon. Porous board-shaped elements with closed argon-filled pores produced this way have found application especially in insulation systems for cooling devices, in transport, and in construction industry.

Claims

Patent claims

1. A thermal insulation with cellular structure having at least two layers of film extruded from a polymer, preferably polyethylene, joined with each other by means of welding method, of which one layer has a completely flat surface, and the other has profiled hollows called bubbles, or produced in the form of boards of polymer foam with cellular structure filled up with a gas characterised in that profiled hollows (17) made in layer (15) are filled entirely with gas (8) having density higher that the density of air under atmospheric pressure, said gas being argon.

2. The thermal insulation according to claim 1 characterised in that its profiled hollows (17) are filled with argon in from 0.5% to 100% by volume.

3. The thermal insulation according to claim 1 characterised in that its board-shaped form produced by means of foaming has closed cells filled with argon.

4. A method of producing thermal insulation with cellular structure consisting in producing said insulation from intermediate products in the form of at least two layers of polymer film subject to further processing aimed at production of the finished product in the form of film band consisting in making profiled hollows commonly called bubbles in one of the layers and joining the layers with each other by means of welding method, or in producing said insulation from intermediate product in the form of polymer granulate subject to further processing also aimed at production of a ready-to-use intermediate product in the form of film band consisting in producing out of it a first film layer flat on both surfaces and a second film layer with profiled hollows made in it and joining the two film layers with each other by means of welding method, or in producing said insulation from polymer granulate and foaming agents by means of foaming to obtain a finished product in the form of foamed boards with closed cellular structure characterised in that all technological operations connected with production of finished product in the form of thermal insulation are carried out in argon atmosphere.

5. The method according to claim 4 characterised in that all technological operations connected with producing the finished product in the form of thermal insulation are realised by devices (5) or (21) or (25) entirely immersed in argon (8) constant level "P" of which is maintained by means of a set of sensors (13).

6. A set of devices for producing thermal insulation with cellular structure, especially bubble film, comprising any known device for producing gas-filled bubble film characterised in that it comprises a magazine (1) of intermediate products in the form of flat thin polymer films or a magazine (20) of intermediate products in the form of polyethylene granules or a magazine (22) of polystyrene granules and agents used to foam them, said magazines being connected, via dispensing device (2) or (23), with housing (4) or with chamber (24) in which the following are mounted, respectively: a device (5) for producing bubble film by means of welding method immersed entirely with argon (8) up to level "P", or device (21) for producing, out of the granules, two thin layers of polymer film, one of which provided with profiled hollows (17) and second with flat surfaces (14), and for joining them with each other by means of welding method, or device (25) producing board-shaped elements from foamed granules, whereas lower ends of segments (3) and (3)' of the housing (4) and chamber (24) are connected, via conduits (9) or (29), with reservoir (10) of argon (8) or with reservoir (27) of argon (8), said reservoirs being equipped with control system (1 1) or (28) which in turn, via conduits (12) or (29), are connected with sets of sensors (13) controlling level "P" of argon (8) in which devices (5), (21), and (25) are immersed.