GB2051073A - Expanding and Molding Pre- foamed Plastic Granules - Google Patents
Expanding and Molding Pre- foamed Plastic Granules Download PDFInfo
- Publication number
- GB2051073A GB2051073A GB8017610A GB8017610A GB2051073A GB 2051073 A GB2051073 A GB 2051073A GB 8017610 A GB8017610 A GB 8017610A GB 8017610 A GB8017610 A GB 8017610A GB 2051073 A GB2051073 A GB 2051073A
- Authority
- GB
- United Kingdom
- Prior art keywords
- heating medium
- mold
- process according
- steam
- plastic granules
- 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.)
- Withdrawn
Links
- 229920000426 Microplastic Polymers 0.000 title claims abstract description 12
- 238000000465 moulding Methods 0.000 title claims abstract description 12
- 238000010438 heat treatment Methods 0.000 claims abstract description 20
- 239000011261 inert gas Substances 0.000 claims abstract description 13
- 229920001169 thermoplastic Polymers 0.000 claims abstract description 11
- 239000004416 thermosoftening plastic Substances 0.000 claims abstract description 11
- 239000008187 granular material Substances 0.000 claims abstract description 9
- 238000010792 warming Methods 0.000 claims abstract description 7
- VZGDMQKNWNREIO-UHFFFAOYSA-N tetrachloromethane Chemical compound ClC(Cl)(Cl)Cl VZGDMQKNWNREIO-UHFFFAOYSA-N 0.000 claims abstract description 6
- 238000000034 method Methods 0.000 claims description 31
- 239000007789 gas Substances 0.000 claims description 14
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 239000000126 substance Substances 0.000 claims description 6
- 239000002360 explosive Substances 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- 229920006329 Styropor Polymers 0.000 claims description 3
- 239000004604 Blowing Agent Substances 0.000 claims description 2
- 230000015572 biosynthetic process Effects 0.000 claims description 2
- 230000002401 inhibitory effect Effects 0.000 claims description 2
- 238000001816 cooling Methods 0.000 claims 1
- 229920006327 polystyrene foam Polymers 0.000 claims 1
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 abstract description 6
- 229920006248 expandable polystyrene Polymers 0.000 abstract description 4
- 239000006260 foam Substances 0.000 abstract description 4
- 229910002092 carbon dioxide Inorganic materials 0.000 abstract description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 abstract description 2
- 239000001569 carbon dioxide Substances 0.000 abstract description 2
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 abstract description 2
- 238000005245 sintering Methods 0.000 abstract description 2
- 239000003570 air Substances 0.000 abstract 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 238000007664 blowing Methods 0.000 description 3
- 239000004215 Carbon black (E152) Substances 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000009841 combustion method Methods 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000007792 gaseous phase Substances 0.000 description 1
- 150000008282 halocarbons Chemical class 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 230000002522 swelling effect Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
- C08J9/22—After-treatment of expandable particles; Forming foamed products
- C08J9/228—Forming foamed products
- C08J9/232—Forming foamed products by sintering expandable particles
-
- 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
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/34—Auxiliary operations
- B29C44/3415—Heating or cooling
- B29C44/3426—Heating by introducing steam in the mould
-
- 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
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/34—Auxiliary operations
- B29C44/36—Feeding the material to be shaped
- B29C44/38—Feeding the material to be shaped into a closed space, i.e. to make articles of definite length
- B29C44/44—Feeding the material to be shaped into a closed space, i.e. to make articles of definite length in solid form
- B29C44/445—Feeding the material to be shaped into a closed space, i.e. to make articles of definite length in solid form in the form of expandable granules, particles or beads
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2025/00—Use of polymers of vinyl-aromatic compounds or derivatives thereof as moulding material
- B29K2025/04—Polymers of styrene
- B29K2025/06—PS, i.e. polystyrene
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2325/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Derivatives of such polymers
- C08J2325/02—Homopolymers or copolymers of hydrocarbons
- C08J2325/04—Homopolymers or copolymers of styrene
- C08J2325/06—Polystyrene
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
- Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
- Molding Of Porous Articles (AREA)
Abstract
Moldings are produced from foamable thermoplastics, especially from pre-foamed polystyrene foam, by expanding and sintering in a mold pre- foamed plastic granules with supply of heat, a hot inert gas and/or hot air being employed in place of steam as the heating medium for warming the pre-foamed thermoplastic granules and, if desired, the mold. The heating medium e.g. air, nitrogen or carbon dioxide, may contain steam and carbon tetrachloride.
Description
SPECIFICATION
Process for the Production of Mouldings from
Foamable Thermoplastics
The present invention relates to a process for the production of moldings from foamable thermoplastics, especially from pre-foamed polystyrene foam, for example Styropor or
Styrocell, in which pre-foamed plastic granules are post-expanded and sintered in a mold with supply of heat.
In recent decades a large number of processes and devices for the production of moldings from expandable polystyrene foam (EPS) has been disclosed in which pre-foamed plastic granules are post-foamed (post-expanded), and sintered, in a mold with supply of heat. With these known princesses, either the mold only is warmed from the outside, this, of course, being a reasonable possibility only in the case of very thin moldings, or molds are employed which are provided with holes or slits through which the pre-foamed plastic granules cannot emerge but the steam used for warming, or the hot water used for warming, can enter into the mold and between the granules.Furthermore, processes and devices of the initially mentioned type have been disclosed, in which a vacuum is applied to the mold before it is filled with the pre-foamed plastic granules and the mold is pre-heated from the outside, without the heating medium necessary for this being able to penetrate into the mold. A small amount of steam is passed in during or after the introduction of the granules into the mold and a vacuum continues to be applied to the mold during the entire filling time. In this case, the mold again has holes or slits, but these open into special vacuum or steam feed lines.
As already mentioned, with all of these processes the heating medium used is steam or hot water, at least where the granules to be foamed come into contact with the heating medium. A fact which has proved particularly disadvantageous in these processes is that the moldings always have a certain moisture content, which is due to water of condensation, and that the molds become corroded due to the influence of the hot steam or the hot water. The disadvantages associated with this are obvious. A further disadvantage, which is associated with this process, becomes particularly evident when steam is used, since an enormous amount of energy is consumed when the transition is made from the liquid to the gaseous phase and this energy can subsequently be only partly recovered.
The object of the invention is, therefore, to provide a new process which enables dry moldings to be obtained immediately after shaping, so that subsequent prolonged storage in order to dry the moldings is superfluous.
Moreover, this process should be designed in such a way that the heating medium exerts no corrosive influences on the mold and the lines and, at the same time, the process should be so designed that there is a considerable saving in energy and, moreover, the installations necessary for generating the steam can be dispensed with.
This object has been achieved by using a hot inert gas and/or hot air in place of steam as the heating medium for warming the pre-foamed thermoplastic granules and, if desired, the mold.
The invention thus relates to a process for the production of moldings from foamable thermoplastics, especially from pre-foamed polystyrene foam, for example Styropor, Styrocell or the like, in which pre-foamed plastic granules are expanded, and sintered, in a mold with the supply of heat, which process is characterized in that a hot inert gas and/or hot air is employed in place of steam as the heating medium for warming the pre-foamed thermoplastic granules and, if desired, the mold.
Inert gases which can be employed are all gases which do not tend, like, for example, steam, to condense under the given process conditions and do not enter into any chemical reactions with the plastic and the blowing gas contained therein.
Suitable inert gases therefore include, for example, nitrogen and carbon dioxide. For reasons of economy, the heating medium used is preferably hot air, but care must be taken that it is not possible for an explosive gas mixture to form with the blowing gas which issues from the plastic granules, if this blowing gas is a combustible gas. In order to prevent the formation of such an explosive gas mixture, it is necessary either to lower the oxygen content of the air, which can be effected, for example, by burning hydrogen in the stream of air to be used, in which case a certain amount of steam is added to the stream of air at the same time, as a result of the combustion. On the other hand, of course, it is also possible to dispense with the combustion of hydrogen in the stream of air if, instead of this, steam or another ignition-inhibiting compound is added to the stream of hot air.An ignitioninhibiting compound of this type can be a halogenated hydrocarbon, for example carbon tetrachloride or another known halogenated, preferably fluorinated, hydrocarbon. If a process which operates with such additives is to be designed in an economical manner, it is, of course, necessary to recover the substances from the heating medium again. Therefore, when such substances are added, the process is preferably carried out using molds which permit a vacuum to be applied to the internal space of the mold even whilst the heating medium is flowing through the mold, the heating medium being passed, after it leaves the mold, through appropriate absorbers or adsorber columns or freeze traps.At the same time, this procedure makes it possible also to recover the blowing agent which issues from the plastic granules, if appropriate absorption or adsorption columns or cold traps are incorporated in the system.
Of course, it is also possible for a gas stream of
hot air with a low oxygen content to be produced
by burning a hydrocarbon in the stream of gas
subsequently to be used as hot air, in which case not only steam but, at the same time, an additional CO2 content are then obtained in the hot air; however, care should be taken that a substantial proportion of carbon monoxide does not form. When pure inert gases are used it is, of course, advisable to design the process in such a way that the hot inert gas is cycled after leaving the mold and this is possible by operating in a corresponding vacuum/pressure system.
Of course, the rare gases could also be employed as the inert gases, but, at least at present, this will not be done for masons of economy.
Conventional methods are used for warming the inert gas and/or the air and advantageously use is made of the combustion method described above. Further heating can be achieved by passing the heating medium over electrically heated plates or wires. Preferably, the heating medium is heated to a temperature such that it has a temperature of between 110 and 1 300C on entry into the mold.
According to a particularly advantageous embodiment of the invention, the inert gas and/or the air contains an organic compound which is gaseous under the process conditions and, under the process conditions, additionally exerts a swelling action on the granule particles present in the mold, so that sintering is intensified by an additional "swell-welding effect". In order additionally to obtain this effect, it is necessary to use relatively high-boiling substances which produce a "tacky" surface at the surface of the granule particles even at the relatively high process temperatures. Organic substances suitable for this purpose are in particular those which, on the one hand, are non-combustible and, on the other hand, constitute a good solvent with regard to the particular thermoplastic employed.
Since the use, according to the invention, of hot inert gases and/or hot air replaces the use of steam, the other process characteristics correspond to those of the prior art, so that it is superfluous to enter into a precise description of the process in the present case.
Of course, in the case of individual gas components, these can also be introduced separately into the mold or, alternatively, can be combined just before entry into the mold.
Claims (8)
1. Process for the production of moldings from foamable thermoplastics, especially from prefoamed polystyrene foam, for example Styropor
Registered Trade Mark, Styrocell Registered Trade
Mark or the like, in which pre-foamed plastic granules are expanded, and sintered, in a mold with supply of heat, characterized in that a hot inert gas and/or hot air is employed in place of steam as the heating medium for warming the pre-foamed thermoplastic granules and, if desired, the mold.
2. Process according to claim 1, characterized in that the heating medium contains steam.
3. Process according to claim 1 and 2, characterized in that the heating medium contains steam in an amount such that it reaches the dew point only on cooling to a temperature of about 80 to 900C.
4. Process according to claim 1 to 3, characterized in that the proportion of steam in the hot air is so high that the formation of an explosive gas mixture is not possible when the blowing agent contained in the plastic granules is a gas which can form an explosive gas mixture in combination with air.
5. Process according to claim 1 to 4, characterized in that the hot inert gas contains a vaporized organic substance which is able to swell the plastic granules under the process conditions.
6. Process according to claim 1 to 5, characterized in that the heating medium used is air to which a gaseous, ignition-inhibiting organic substance, for example carbon tetrachloride, has been added.
7. Process according to claim 1 to 6, characterized in that the heating medium enters into the mold at a temperature of between 110 and 1300C.
8. Process according to claim 1 for the production of mouldings from foamable thermoplastics, substantially as hereinbefore described and exemplified.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19792922315 DE2922315A1 (en) | 1979-05-31 | 1979-05-31 | METHOD FOR PRODUCING FOAMABLE THERMOPLASTIC PLASTICS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2051073A true GB2051073A (en) | 1981-01-14 |
Family
ID=6072228
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8017610A Withdrawn GB2051073A (en) | 1979-05-31 | 1980-05-29 | Expanding and Molding Pre- foamed Plastic Granules |
Country Status (13)
| Country | Link |
|---|---|
| JP (1) | JPS5628836A (en) |
| BE (1) | BE883586A (en) |
| BR (1) | BR8003418A (en) |
| DE (1) | DE2922315A1 (en) |
| ES (1) | ES492029A0 (en) |
| FR (1) | FR2457881A1 (en) |
| GB (1) | GB2051073A (en) |
| IL (1) | IL60200A0 (en) |
| IT (1) | IT1140984B (en) |
| MA (1) | MA18863A1 (en) |
| NL (1) | NL8003137A (en) |
| PT (1) | PT71334A (en) |
| SE (1) | SE8004058L (en) |
-
1979
- 1979-05-31 DE DE19792922315 patent/DE2922315A1/en not_active Withdrawn
- 1979-06-08 FR FR7914779A patent/FR2457881A1/en active Granted
-
1980
- 1980-05-29 NL NL8003137A patent/NL8003137A/en not_active Application Discontinuation
- 1980-05-29 GB GB8017610A patent/GB2051073A/en not_active Withdrawn
- 1980-05-30 ES ES492029A patent/ES492029A0/en active Granted
- 1980-05-30 BR BR8003418A patent/BR8003418A/en unknown
- 1980-05-30 MA MA19061A patent/MA18863A1/en unknown
- 1980-05-30 IT IT22470/80A patent/IT1140984B/en active
- 1980-05-30 SE SE8004058A patent/SE8004058L/en unknown
- 1980-05-30 IL IL60200A patent/IL60200A0/en unknown
- 1980-05-30 PT PT71334A patent/PT71334A/en unknown
- 1980-05-30 JP JP7163680A patent/JPS5628836A/en active Pending
- 1980-05-30 BE BE0/200852A patent/BE883586A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| NL8003137A (en) | 1980-12-02 |
| IT8022470A0 (en) | 1980-05-30 |
| MA18863A1 (en) | 1980-12-31 |
| SE8004058L (en) | 1980-12-01 |
| FR2457881A1 (en) | 1980-12-26 |
| DE2922315A1 (en) | 1981-02-05 |
| ES8102167A1 (en) | 1980-12-16 |
| BR8003418A (en) | 1981-01-05 |
| FR2457881B3 (en) | 1982-05-21 |
| PT71334A (en) | 1980-06-01 |
| JPS5628836A (en) | 1981-03-23 |
| IT1140984B (en) | 1986-10-10 |
| BE883586A (en) | 1980-09-15 |
| IL60200A0 (en) | 1980-07-31 |
| ES492029A0 (en) | 1980-12-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |