CA1055667A - Manufacture of thin walled plastics material articles - Google Patents
Manufacture of thin walled plastics material articlesInfo
- Publication number
- CA1055667A CA1055667A CA236,876A CA236876A CA1055667A CA 1055667 A CA1055667 A CA 1055667A CA 236876 A CA236876 A CA 236876A CA 1055667 A CA1055667 A CA 1055667A
- Authority
- CA
- Canada
- Prior art keywords
- web
- roller
- rollers
- chamber
- heated
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B13/00—Conditioning or physical treatment of the material to be shaped
- B29B13/02—Conditioning or physical treatment of the material to be shaped by heating
- B29B13/023—Half-products, e.g. films, plates
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
- B29C35/04—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould using liquids, gas or steam
- B29C35/06—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould using liquids, gas or steam for articles of indefinite length
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
- B29C35/04—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould using liquids, gas or steam
- B29C35/045—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould using liquids, gas or steam using gas or flames
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
- B29C35/04—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould using liquids, gas or steam
- B29C35/049—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould using liquids, gas or steam using steam or damp
Landscapes
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Health & Medical Sciences (AREA)
- Oral & Maxillofacial Surgery (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
- Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
- Shaping Of Tube Ends By Bending Or Straightening (AREA)
Abstract
A B S T R A C T
In the manufacture of plastics articles by forming them from heat-softened thin sheet materials it is desirable to accurately control the temperature throughout the material. This requirement is met by passing the mater-ial in contact with thermostatically controlled heating rollers within a hot-air chamber prior to the forming process itself. The controlled heating process is applicable to several thermoforming techniques such as vacuum forming and pressure forming for making thin walled articles such as drinking cups.
In the manufacture of plastics articles by forming them from heat-softened thin sheet materials it is desirable to accurately control the temperature throughout the material. This requirement is met by passing the mater-ial in contact with thermostatically controlled heating rollers within a hot-air chamber prior to the forming process itself. The controlled heating process is applicable to several thermoforming techniques such as vacuum forming and pressure forming for making thin walled articles such as drinking cups.
Description
3~0S~;6'7 1 This invention relates to the manufacture of thin walled plas-tics material articles which are formed from web or sheet plastics materials (which may he laminates~O
Any suitable -technique such as vacuum forming, pre~sure ~orming, plug assist or mechanical formin~ or any combination of such techni~ues may be used in the forming of the articles, but in all cases the sheet material i~ . :
heated to effect a degree of softening of the material so that it can be formed and therefore -~he forming of the articles will be referred~to simply and generally as "thermoforming".
Thermoforming is of cour~e well known and is wldely practised, and there are many thermoformed article~ ln every day use in many countries o~ the world, ~uch articles :.
including do~estic holloware and drinking cups. . :~
Certain materials, and in particular polypropylene, polyethylene and expanded plastics sheet re~uire to be :~
thermoformed at very accurate temperatures in order to achieve . .
high ~peed production and high quali-ty produ~ts. Conve~tional methods of heating such as infra-red heaters do not provide suf~icient accuracy of heating to achieve these desirable features even when the sheets being thermoformed are of uniform thickness which in commercial practice i~ not usually the case. ~ .
Furthermore, when the heating is carried out by a radiation process, many types of plastics sheet wrinkle or ~ :
sag under the heating ac-tion which causes even further temperature variations in the heated shee-t.
Any suitable -technique such as vacuum forming, pre~sure ~orming, plug assist or mechanical formin~ or any combination of such techni~ues may be used in the forming of the articles, but in all cases the sheet material i~ . :
heated to effect a degree of softening of the material so that it can be formed and therefore -~he forming of the articles will be referred~to simply and generally as "thermoforming".
Thermoforming is of cour~e well known and is wldely practised, and there are many thermoformed article~ ln every day use in many countries o~ the world, ~uch articles :.
including do~estic holloware and drinking cups. . :~
Certain materials, and in particular polypropylene, polyethylene and expanded plastics sheet re~uire to be :~
thermoformed at very accurate temperatures in order to achieve . .
high ~peed production and high quali-ty produ~ts. Conve~tional methods of heating such as infra-red heaters do not provide suf~icient accuracy of heating to achieve these desirable features even when the sheets being thermoformed are of uniform thickness which in commercial practice i~ not usually the case. ~ .
Furthermore, when the heating is carried out by a radiation process, many types of plastics sheet wrinkle or ~ :
sag under the heating ac-tion which causes even further temperature variations in the heated shee-t.
-2- ~ ~.
,- ..
.. , ., . :
:lOS5667 `, 1 The present invention seeks to provide a method of heating which is useful for a very wide range of plastics sheets including polystyrene, ~.B.S. acrylonitrile, nylon, polyester, polyvinyl chloride, cellulose acetate, the so-called "filled" plastics material comprising plastics and inorganic ~-particular material and indeed any sheet which is capable of being thermoformed, and in which the aforesaid disadvantages are obviated or mitigated.
According to the present invention there is provided a ~ method for the manufacture of thin walled plastics material articles, wherein the articles are thermoformed in a heated web af the plastics material and the web is heated by being passed round heated roller means.
.
~ Ieating the web by contact with heated roller means and hot gas and/or vapour ensures even heating of the web across its width, and the web can at no point reach a temperature which is greater than that of the roller means and gas and~or vapour.
The web may be fed into and out of a chamber containing the roller means and gaseous and/or liquid environment.
The web preferably is continuous and travels directly to a thermoforming machine in which the articles are formed and the method is repeated. The construction of the articles is of course immaterial to this invention.
.
,- ..
.. , ., . :
:lOS5667 `, 1 The present invention seeks to provide a method of heating which is useful for a very wide range of plastics sheets including polystyrene, ~.B.S. acrylonitrile, nylon, polyester, polyvinyl chloride, cellulose acetate, the so-called "filled" plastics material comprising plastics and inorganic ~-particular material and indeed any sheet which is capable of being thermoformed, and in which the aforesaid disadvantages are obviated or mitigated.
According to the present invention there is provided a ~ method for the manufacture of thin walled plastics material articles, wherein the articles are thermoformed in a heated web af the plastics material and the web is heated by being passed round heated roller means.
.
~ Ieating the web by contact with heated roller means and hot gas and/or vapour ensures even heating of the web across its width, and the web can at no point reach a temperature which is greater than that of the roller means and gas and~or vapour.
The web may be fed into and out of a chamber containing the roller means and gaseous and/or liquid environment.
The web preferably is continuous and travels directly to a thermoforming machine in which the articles are formed and the method is repeated. The construction of the articles is of course immaterial to this invention.
.
- 3 ~5566~7 1 The web preferably travels into and out of the cha~ber in a horizontal direction and in the same plane, and the roller means may comprise three rollers lying with their axes horizontal, two of the rollers lying above the third roller and disposed symmetrically relative to the vertical plane containing the third roller. Each roller i8 preferably heated by circulating hot oil therethrough.
The web travels over and round one of the upper rollers, round the lower roller and round and over the other upper roller, so as to deEine a pa~h having said vertica} plane as an axis of sy~unetry. The rollers preferably are of such size and are so dl~posed that the web, in travelling through the chamber, has e~ual contack with the rollers on each side of the sheet.
There may be inle-t means and ou-tlet means by which gaseous and/or vapour medium can be injected into and removed from the chambers. The temperature of the rollers and the gaseou~ and/or vapour medium praferably is accuxately controlled, so that the web will be heated to an even, accurate temperature, which preferably is such that the web i8 ready for thermoforming.
The temperature of -the rollers and gaseous and/or vapour medium will preferably be thermosta-tically controlled in order to ensure that the web is maintained at the critical temperature.
The minimum length of time which the sheet must be in the chamber !:
to reach the desired temperature will depend upon the dimensions ,~, , , ' . .
~^ l 1~56~7 1 of the sheet but in any case -this time can be adjusted to suit the material being heated. There is no maximum heating time as the temperature of the web cannot get higher than the chamber temperature.
Articles, such as domestic holloware, formed from polypropylene heated in this manner can be reliab}y produced in large quantities and taking large numbers on average they exhibit an excellent surface finish, toughness and clarity which are bet-ter than those characteristics ln conven-tionall~ formed polypropylene articles.
As the thermoorming machine will pxobably operate on a cyclic basis requiring a dwell or a batch of the articles can be formed, the web will also require to dwell cyclically in contac-t with the rollers.
It is not necessary that the heating effected in the heating chamber should comprise the whole of the heatin~
of the sheet. Pre-heating and/or post heating ~uch a~
steam heating, radiant heating or the like may be employad.
Thi~may be suitable where the plastics material web being heated is polystyrene, as the heating chamker could be used to perform the major portion of the heating of the sheet, and for example, conventional radiant heaters, which are inefficient, could be used for only a small post heating step of bringing the web up to forming temperature from the temperature at which it leaves the li~uid bath. In any event, .
~ ' :
1~5S667 1 the roller contact and gaseouq and/or vapour heating in the heating chamber is always beneficial because of th~ even temperature di~tribution which is achieved.
The invention thus provides a simple method whereby ;~
plastics material in web form can be heated evenly, enab7ing the effective use of plastics materials such as the polyolefins e ~. polypropylene, for thermoformed articles produced in large numbers; the cycle time can be made very short and in many cases a cheaper yet superior article can be produced.
The invention also provides articles produced according to the method as aforésaid.
Al~o according to the invention there i~ provided apparatus for use in the manufacture of thin wal}ed plastic3 materlal articles comprising means defining a heating chamber, exit and entry means whereby a web of plastic~ material can be fed into and out of the chamber, roller means around which the web can be passed, means whereby the roller means can be heated, and inlet and outlet mean~ whereby hot gaseous and/or vapour can be injected into and removed from said chamber.
An embodiment of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawing, of which the single figure is a sectional side elevation o~ heating chamber.
Referring to the drawing, the heating chamber is defined by a cabinet having front and rear walls lO and 12, top and bottom walls 14 and 16, and two side walls, of ~ich onLy slde wall 18 i~ shown, as the figure i8 a sectional elevationO The front f~r~ i ~
~ 1113 55667 1 wall at its top portion is provided with an entry slot 20, whilst the rear wall 12 is provided with an exit slot 22. These slots 20 and 22 are in horizontal alignment and enable the passage of a thermoformable web 24, such as a web of polypropylene to enter the chamber through slot 20 and exit from the chamber through slot 22. -The front wall 10 and the rear wall 12 are also pro~ided with inlets 26 for gaseous and/or vapour heating medium. In this example, the heating medium is air. In use, heated air is 10 continuously inserted into the chamber through these inlets 26 ~
and is extracted by extraction pipes 28 which are located, as - -shown, above and below the entry slot 20 and above and below the .. . .
exit slot 22.
Inside the chamber, there are three heated rollers 30, 32 and 34. These rollers are disposed with their a~is parallel and horizontal, and the rollers 30 and 32 are disposed at a higher level than the roller 34. The rollers 30 and 32 are in fact symmetrically disposed about a vertical plane passing through the axis of roller 34. These rollers are heated by circulating heated oil through the hollow interiors thereof, but their peripheral surfaces are metallic or good conduction ~ -of heat from the roller surfaces to the web 2~, in contact therewith. The web 24 after passing infra-red pre-heaters 36 travels, as shown, over roller 30, round roller 34 and then ., , ~ .
556~i7 "'- ' I over roller 32. The web eventually leaves via exit slot 22 and it will be seen that the entering stretch of web and the leaving stretch in relation to the chamber, are disposed in the same horizontal plane.
The temperatures of the rollers and the environment in the chamber will be maintained within accurate limits to ensure that the web 24 is heated to an even and regular temperature, so that it will be suitable for passing directly from exit 22, to a thermoforming machine in which the articles are produced in the web 24. These tempera-tures will be controlled by the circulation both of the environment o the chaTnber, and the oil of -the heating rollers, and suitable thermostats will be employed to maintain these temperatures within accurate lim~s. For example the air which is injected through inlets 26 may be at 160 centigrade for polypropylene sheet and the rollers 30, 32 and 34 would be maintained at a similar temperature.
The roller sizes and disposition are preferably selected so that as -the web 24 passes through the apparatus there will be the same amount of contact between roller and web, at each side of the web at all times, and the rollers 30, 34 and 32 may be driven at slightly higher speeds, in that order, in order to compensate for any lengthwise expansion of the sheet 24 which may take place during the heating process and to ensure that the web 24 remains in intimate contact with the rollexs.
,`'' ' ' ' ',;',' ''.'" '; '' ~': ' ' , ~ 5~i66i7 1 Furthermore, it is possible to have the rollers 30, 34 and 32 so positioned as to define nips between roller 30 and 34 on the one hand, and roller 34 and 32 on the other hand in order to effect or assist the feeding of the web through the chamber.
Whilst the preferred construction o~ machine has been described, it is to be appreciated that modifications may be made without parting from the scope of the invention.
For example, it would be possible to provide an apparatu~
ln which only two rollers are provided, with the web travelling in "S" formation round these rows and having e~ual web to roller con-tact on each side o~ the web. Furthermore, the chamber may contain suitable baffling in order to ensure that the hot air which is being injected into the chamber will tend to be directed towards the rollers.
The web travels over and round one of the upper rollers, round the lower roller and round and over the other upper roller, so as to deEine a pa~h having said vertica} plane as an axis of sy~unetry. The rollers preferably are of such size and are so dl~posed that the web, in travelling through the chamber, has e~ual contack with the rollers on each side of the sheet.
There may be inle-t means and ou-tlet means by which gaseous and/or vapour medium can be injected into and removed from the chambers. The temperature of the rollers and the gaseou~ and/or vapour medium praferably is accuxately controlled, so that the web will be heated to an even, accurate temperature, which preferably is such that the web i8 ready for thermoforming.
The temperature of -the rollers and gaseous and/or vapour medium will preferably be thermosta-tically controlled in order to ensure that the web is maintained at the critical temperature.
The minimum length of time which the sheet must be in the chamber !:
to reach the desired temperature will depend upon the dimensions ,~, , , ' . .
~^ l 1~56~7 1 of the sheet but in any case -this time can be adjusted to suit the material being heated. There is no maximum heating time as the temperature of the web cannot get higher than the chamber temperature.
Articles, such as domestic holloware, formed from polypropylene heated in this manner can be reliab}y produced in large quantities and taking large numbers on average they exhibit an excellent surface finish, toughness and clarity which are bet-ter than those characteristics ln conven-tionall~ formed polypropylene articles.
As the thermoorming machine will pxobably operate on a cyclic basis requiring a dwell or a batch of the articles can be formed, the web will also require to dwell cyclically in contac-t with the rollers.
It is not necessary that the heating effected in the heating chamber should comprise the whole of the heatin~
of the sheet. Pre-heating and/or post heating ~uch a~
steam heating, radiant heating or the like may be employad.
Thi~may be suitable where the plastics material web being heated is polystyrene, as the heating chamker could be used to perform the major portion of the heating of the sheet, and for example, conventional radiant heaters, which are inefficient, could be used for only a small post heating step of bringing the web up to forming temperature from the temperature at which it leaves the li~uid bath. In any event, .
~ ' :
1~5S667 1 the roller contact and gaseouq and/or vapour heating in the heating chamber is always beneficial because of th~ even temperature di~tribution which is achieved.
The invention thus provides a simple method whereby ;~
plastics material in web form can be heated evenly, enab7ing the effective use of plastics materials such as the polyolefins e ~. polypropylene, for thermoformed articles produced in large numbers; the cycle time can be made very short and in many cases a cheaper yet superior article can be produced.
The invention also provides articles produced according to the method as aforésaid.
Al~o according to the invention there i~ provided apparatus for use in the manufacture of thin wal}ed plastic3 materlal articles comprising means defining a heating chamber, exit and entry means whereby a web of plastic~ material can be fed into and out of the chamber, roller means around which the web can be passed, means whereby the roller means can be heated, and inlet and outlet mean~ whereby hot gaseous and/or vapour can be injected into and removed from said chamber.
An embodiment of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawing, of which the single figure is a sectional side elevation o~ heating chamber.
Referring to the drawing, the heating chamber is defined by a cabinet having front and rear walls lO and 12, top and bottom walls 14 and 16, and two side walls, of ~ich onLy slde wall 18 i~ shown, as the figure i8 a sectional elevationO The front f~r~ i ~
~ 1113 55667 1 wall at its top portion is provided with an entry slot 20, whilst the rear wall 12 is provided with an exit slot 22. These slots 20 and 22 are in horizontal alignment and enable the passage of a thermoformable web 24, such as a web of polypropylene to enter the chamber through slot 20 and exit from the chamber through slot 22. -The front wall 10 and the rear wall 12 are also pro~ided with inlets 26 for gaseous and/or vapour heating medium. In this example, the heating medium is air. In use, heated air is 10 continuously inserted into the chamber through these inlets 26 ~
and is extracted by extraction pipes 28 which are located, as - -shown, above and below the entry slot 20 and above and below the .. . .
exit slot 22.
Inside the chamber, there are three heated rollers 30, 32 and 34. These rollers are disposed with their a~is parallel and horizontal, and the rollers 30 and 32 are disposed at a higher level than the roller 34. The rollers 30 and 32 are in fact symmetrically disposed about a vertical plane passing through the axis of roller 34. These rollers are heated by circulating heated oil through the hollow interiors thereof, but their peripheral surfaces are metallic or good conduction ~ -of heat from the roller surfaces to the web 2~, in contact therewith. The web 24 after passing infra-red pre-heaters 36 travels, as shown, over roller 30, round roller 34 and then ., , ~ .
556~i7 "'- ' I over roller 32. The web eventually leaves via exit slot 22 and it will be seen that the entering stretch of web and the leaving stretch in relation to the chamber, are disposed in the same horizontal plane.
The temperatures of the rollers and the environment in the chamber will be maintained within accurate limits to ensure that the web 24 is heated to an even and regular temperature, so that it will be suitable for passing directly from exit 22, to a thermoforming machine in which the articles are produced in the web 24. These tempera-tures will be controlled by the circulation both of the environment o the chaTnber, and the oil of -the heating rollers, and suitable thermostats will be employed to maintain these temperatures within accurate lim~s. For example the air which is injected through inlets 26 may be at 160 centigrade for polypropylene sheet and the rollers 30, 32 and 34 would be maintained at a similar temperature.
The roller sizes and disposition are preferably selected so that as -the web 24 passes through the apparatus there will be the same amount of contact between roller and web, at each side of the web at all times, and the rollers 30, 34 and 32 may be driven at slightly higher speeds, in that order, in order to compensate for any lengthwise expansion of the sheet 24 which may take place during the heating process and to ensure that the web 24 remains in intimate contact with the rollexs.
,`'' ' ' ' ',;',' ''.'" '; '' ~': ' ' , ~ 5~i66i7 1 Furthermore, it is possible to have the rollers 30, 34 and 32 so positioned as to define nips between roller 30 and 34 on the one hand, and roller 34 and 32 on the other hand in order to effect or assist the feeding of the web through the chamber.
Whilst the preferred construction o~ machine has been described, it is to be appreciated that modifications may be made without parting from the scope of the invention.
For example, it would be possible to provide an apparatu~
ln which only two rollers are provided, with the web travelling in "S" formation round these rows and having e~ual web to roller con-tact on each side o~ the web. Furthermore, the chamber may contain suitable baffling in order to ensure that the hot air which is being injected into the chamber will tend to be directed towards the rollers.
Claims (10)
1. A method for the manufacture of thin walled plastics material articles, wherein a continuous web of plastics material is heated by radiation heating means and then is passed round heated roller means to provide even temperature distribution in the web and the thus heated web whilst still hot is fed step by step with dwell times between steps to a thermoforming machine whereat art-icles are thermoformed therein during said dwell times.
2. A method according to claim 1, wherein the roller means comprise three rollers lying with their axes horizontal, two of the rollers lying above the third roller and disposed symmetrically relative to the vertical plane containing the axis of the third roller, and the web travels over and round one of the upper rollers, round the lower roller and round and over the other upper roller, so as to define a path having said vertical plane as an axis of symmetry.
3. A method according to claim 2, wherein the rollers are of such size and are so disposed that the web in travelling round said rollers, has equal contact with the rollers on each side of the sheet.
4. A method according to claim 2, wherein each roller is heated by circulating hot oil therethrough.
5. A method according to claim 4, wherein the temperature of the oil circulated through each roller is thermostatically controlled so as to maintain each roller at a constant preselected temperature.
6. A method according to claim 1, wherein the roller means are contained in a chamber containing a heated gaseous and/or vapour environment, and the web preferably travels into and out of the chamber in a horizontal direction and in the same plane and the temperature of the gaseous and/or vapour environment is theremostatically controlled so that it is maintained at a con-stant pre-selected temperature.
7. A method according to claim 6, wherein air is issued to provide the said environment in the chamber.
8. A method according to claim 6 or 7 wherein the gas and/
or vapour providing the environment is circulated through the chamber.
or vapour providing the environment is circulated through the chamber.
9. Apparatus for use in the method of claim 1 comprising radiant heating means for heating the web, roller means around which the web can be passed after passing the radiant heating means, means whereby the roller means can be heated, a cyclically oper-able thermoforming machine, and feed means for feeding the web step by step through the apparatus with dwell times between the steps, said thermoforming machine being located to receive the web from the roller means whilst still hot and to thermoform articles in said web during said dwell times.
10. Apparatus according to claim 9, wherein the roller means are contained in a chamber containing a heated gaseous and/
or vapour environment and the roller means comprise three rollers lying with their axes horizontal, two of the rollers lying above the third roller and disposed symmetrically relative to the vert-ical plane containing the axis of the third roller and web exit and entry means of the chamber are located so that the web can travel into and out of the chamber in a horizontal direction and in the same plane, and in the chamber the web travels over and round one of the upper rollers, round lower roller and round and over the upper roller, so as to define a path having said vertical plane as an axis of symmetry.
or vapour environment and the roller means comprise three rollers lying with their axes horizontal, two of the rollers lying above the third roller and disposed symmetrically relative to the vert-ical plane containing the axis of the third roller and web exit and entry means of the chamber are located so that the web can travel into and out of the chamber in a horizontal direction and in the same plane, and in the chamber the web travels over and round one of the upper rollers, round lower roller and round and over the upper roller, so as to define a path having said vertical plane as an axis of symmetry.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB42888/74A GB1505820A (en) | 1974-10-03 | 1974-10-03 | Manufacture of thin walled plastics material articles |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1055667A true CA1055667A (en) | 1979-06-05 |
Family
ID=10426405
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA236,876A Expired CA1055667A (en) | 1974-10-03 | 1975-10-02 | Manufacture of thin walled plastics material articles |
Country Status (15)
| Country | Link |
|---|---|
| JP (1) | JPS5163864A (en) |
| BE (1) | BE834136A (en) |
| BR (1) | BR7506470A (en) |
| CA (1) | CA1055667A (en) |
| CH (1) | CH608740A5 (en) |
| DE (1) | DE2544042A1 (en) |
| DK (1) | DK440875A (en) |
| ES (1) | ES441450A1 (en) |
| FR (1) | FR2286698A1 (en) |
| GB (1) | GB1505820A (en) |
| IT (1) | IT1043066B (en) |
| NL (1) | NL7511619A (en) |
| NO (1) | NO143199C (en) |
| NZ (1) | NZ178835A (en) |
| SE (1) | SE407031B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2473888A1 (en) * | 1980-01-17 | 1981-07-24 | Erca | METHOD AND DEVICE FOR STERILIZING A THERMOPLASTIC STRIP FOR THE THERMOFORMING OF STERILE CONTAINERS AND STERILE PACKAGING INSTALLATION USING SAID METHOD AND DEVICE |
| DE3311988C1 (en) * | 1983-04-02 | 1984-04-19 | Adolf Illig Maschinenbau Gmbh & Co, 7100 Heilbronn | Preheater for heating a sheet of thermoplastic material |
| DE3926089A1 (en) * | 1989-08-07 | 1991-02-14 | Hassia Verpackung Ag | THERMOFORMING MACHINE WITH A FILM LEAD INPUT PREHEATING DEVICE |
| DE102015005066B4 (en) * | 2015-04-21 | 2021-12-16 | Illig Maschinenbau Gmbh & Co. Kg | A method of moving a web of thermoplastic plastic film through a preheater to heat a web of thermoplastic plastic film |
-
1974
- 1974-10-03 GB GB42888/74A patent/GB1505820A/en not_active Expired
-
1975
- 1975-09-30 DK DK440875A patent/DK440875A/en not_active Application Discontinuation
- 1975-10-01 NZ NZ178835A patent/NZ178835A/en unknown
- 1975-10-01 NO NO753316A patent/NO143199C/en unknown
- 1975-10-01 FR FR7530583A patent/FR2286698A1/en active Granted
- 1975-10-02 CA CA236,876A patent/CA1055667A/en not_active Expired
- 1975-10-02 BE BE160642A patent/BE834136A/en unknown
- 1975-10-02 CH CH7512907A patent/CH608740A5/en not_active IP Right Cessation
- 1975-10-02 DE DE19752544042 patent/DE2544042A1/en not_active Withdrawn
- 1975-10-02 ES ES441450A patent/ES441450A1/en not_active Expired
- 1975-10-02 NL NL7511619A patent/NL7511619A/en not_active Application Discontinuation
- 1975-10-02 IT IT27888/75A patent/IT1043066B/en active
- 1975-10-03 SE SE7511105A patent/SE407031B/en unknown
- 1975-10-03 BR BR7506470*A patent/BR7506470A/en unknown
- 1975-10-03 JP JP50119680A patent/JPS5163864A/ja active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| NO753316L (en) | 1976-04-06 |
| CH608740A5 (en) | 1979-01-31 |
| SE407031B (en) | 1979-03-12 |
| BR7506470A (en) | 1976-08-10 |
| NZ178835A (en) | 1978-03-06 |
| JPS5163864A (en) | 1976-06-02 |
| ES441450A1 (en) | 1977-07-01 |
| FR2286698A1 (en) | 1976-04-30 |
| NO143199B (en) | 1980-09-22 |
| SE7511105L (en) | 1976-04-05 |
| AU8535575A (en) | 1977-04-07 |
| NL7511619A (en) | 1976-04-06 |
| DE2544042A1 (en) | 1976-04-15 |
| GB1505820A (en) | 1978-03-30 |
| NO143199C (en) | 1981-01-07 |
| FR2286698B1 (en) | 1980-04-25 |
| BE834136A (en) | 1976-02-02 |
| DK440875A (en) | 1976-04-04 |
| IT1043066B (en) | 1980-02-20 |
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