CA2341600A1 - Method for increasing thermal convection speed in a thermofusible polymer - Google Patents
Method for increasing thermal convection speed in a thermofusible polymer Download PDFInfo
- Publication number
- CA2341600A1 CA2341600A1 CA002341600A CA2341600A CA2341600A1 CA 2341600 A1 CA2341600 A1 CA 2341600A1 CA 002341600 A CA002341600 A CA 002341600A CA 2341600 A CA2341600 A CA 2341600A CA 2341600 A1 CA2341600 A1 CA 2341600A1
- Authority
- CA
- Canada
- Prior art keywords
- polymer
- ultrasonic vibrations
- source
- thermal
- thermal radiation
- 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.)
- Abandoned
Links
- 229920000642 polymer Polymers 0.000 title claims abstract description 45
- 238000000034 method Methods 0.000 title claims abstract description 15
- 230000005855 radiation Effects 0.000 claims abstract description 22
- 230000005540 biological transmission Effects 0.000 claims abstract description 7
- 229920000139 polyethylene terephthalate Polymers 0.000 claims abstract description 5
- 239000005020 polyethylene terephthalate Substances 0.000 claims abstract description 5
- 239000007788 liquid Substances 0.000 claims abstract description 4
- -1 polyethylene terephthalate Polymers 0.000 claims abstract description 4
- 239000012943 hotmelt Substances 0.000 claims description 10
- 238000002604 ultrasonography Methods 0.000 abstract description 3
- 230000009477 glass transition Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000003856 thermoforming Methods 0.000 description 2
- 238000007664 blowing Methods 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000008521 reorganization Effects 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 229920002994 synthetic fiber Polymers 0.000 description 1
Classifications
-
- 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
- B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
-
- 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
- B29C35/0261—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould using ultrasonic or sonic vibrations
-
- 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
- B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
- B29C35/0805—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation
-
- 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
- B29K2067/00—Use of polyesters or derivatives thereof, as moulding material
-
- 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
- B29K2067/00—Use of polyesters or derivatives thereof, as moulding material
- B29K2067/003—PET, i.e. poylethylene terephthalate
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Thermal Sciences (AREA)
- Oral & Maxillofacial Surgery (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Toxicology (AREA)
- Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
- Lining Or Joining Of Plastics Or The Like (AREA)
Abstract
Description
PROCEDE POUR AUGMENTER LA VITESSE DE CONVECTION
THERMIQUE DANS UN POLYMERE THERMOFUSIBLE
Domaine technique La présente invention concerne un procédé pour augmenter la vitesse de transmission de la chaleur par convection thermique dans un polymère thermofusible.
Technique antérieure Le chauffage des polymères constitue une phase préparatoire préliminaire au traitement des polymères par thermoformage ou par soufflage. II s'effectue habituellement par exposition des polymères à une source de rayonnement thermique extérieure. La montée en température de la masse de polymère s'effectue progressivement par convection selon une pente inclinée descendante. Au début de l'exposition du polymère à la source de rayonnement thermique, la température de la zone proche de la source est plus élevée que celle de la zone éloignée. Progressivement, la différence de température entre la zone proche et la zone éloignée s'atténue. La transmission de la chaleur se fait par convection pendant un temps plus ou moins long qui dépend notamment de la température de la source et de l'épaisseur de la matière.
La durée de montée en température du polymère sur toute son épaisseur conditionne le processus de mise en forme de la matière. Une réduction de cette durée améliore la rentabilité de la production.
Exposé de l'invention La présente invention se propose donc de réduire cette durée de l'échauffement par convection d'une masse de polymère thermofusible.
Ce but est atteint par le procédé tel que défini en préambule et caractérisé
en PROCESS FOR INCREASING CONVECTION SPEED
THERMAL IN A THERMOFUSIBLE POLYMER
Technical area The present invention relates to a method for increasing the speed of heat transfer by thermal convection in a polymer hot melt.
Prior art Heating polymers is a preliminary preparatory phase for treatment of polymers by thermoforming or by blowing. It takes place usually by exposing polymers to a radiation source external thermal. The rise in temperature of the polymer mass takes place gradually by convection along an inclined slope descending. At the start of exposure of the polymer to the source of thermal radiation, the temperature of the area near the source is higher than that of the remote area. Gradually, the difference of the temperature between the near area and the far area decreases. The heat is transmitted by convection for a longer time or shorter which depends in particular on the temperature of the source and the thickness of the material.
The duration of temperature rise of the polymer over its entire thickness conditions the process of shaping the material. A reduction of this duration improves the profitability of production.
Statement of the invention The present invention therefore proposes to reduce this period of the heating by convection of a mass of hot-melt polymer.
This object is achieved by the process as defined in the preamble and characterized in
2 ce que fon expose ledit polymère simultanément à au moins une source de rayonnement thermique et à des vibrations ultrasoniques, et en ce que l'on transmet lesdites vibrations ultrasoniques audit polymère thermofusible en appliquant directement sur une surface dudit polymère au moins une-S sonotrode alimentée par un générateur d'ultrasons.
Outre l'augmentation de la vitesse de transmission de la chaleur à travers la paroi du polymère, l'application de vibrations ultrasoniques et l'exposition simultanée à une source de rayonnement thermique ont pour conséquence une réorganisation des molécules du polymère en favorisant leur orientation dans une direction déterminée.
Selon une première variante de réalisation, l'on expose une surface dudit polymère à une première source de rayonnement thermique et la surface 1S opposée dudit polymère à une seconde source de rayonnement thermique.
De ce fait, on peut moduler le différentiel de température entre les deux surfaces opposées du polymère exposées aux deux sources de rayonnement thermique. On peut ainsi améliorer les caractéristiques physiques du polymère et faire varier la vitesse de transmission de la chaleur en fonction de la forme, de la masse et de la nature de ce polymère.
De préférence, l'on transmet lesdites vibrations ultrasoniques audit polymère thermofusible en mettant au moins une sonotrode en contact avec un liquide 2S intermédiaire qui est en contact avec une surface dudit polymère.
De préférence, lesdites sources de rayonnement thermique ont une température comprise entre 100° et 500°C et la fréquence des vibrations ultrasoniques est comprise entre 15 et 60 kHz.
De façon avantageuse, le temps d'exposition à la source de rayonnement 2 what is exposed by said polymer simultaneously to at least one source of thermal radiation and ultrasonic vibrations, and in that one transmits said ultrasonic vibrations to said hot-melt polymer in applying directly to a surface of said polymer at least one-Sonotrode powered by an ultrasonic generator.
In addition to increasing the rate of heat transmission through the polymer wall, application of ultrasonic vibrations and exposure simultaneous with a source of thermal radiation a reorganization of the polymer molecules by promoting their orientation in a specific direction.
According to a first variant embodiment, a surface of said surface is exposed polymer to a primary source of thermal radiation and the surface 1S opposite said polymer to a second source of thermal radiation.
Therefore, we can modulate the temperature differential between the two opposite surfaces of the polymer exposed to the two sources of radiation thermal. We can thus improve the physical characteristics of the polymer and vary the rate of heat transmission depending on the form, the mass and the nature of this polymer.
Preferably, said ultrasonic vibrations are transmitted to said polymer.
hot-melt by putting at least one sonotrode in contact with a liquid 2S intermediate which is in contact with a surface of said polymer.
Preferably, said sources of thermal radiation have a temperature between 100 ° and 500 ° C and the frequency of vibrations ultrasonic is between 15 and 60 kHz.
Advantageously, the time of exposure to the radiation source
3 thermique est compris entre 1 et 10 secondes et de préférence approximativement égal à 3 secondes.
Selon une manière de procéder particulièrement intéressante, l'on applique-les vibrations ultrasoniques de manière intermittente.
Cette variante permet également de moduler la vitesse de transmission de la chaleur dans le polymère.
La présente invention sera mieux comprise à la description d'une forme de mise en oeuvre préférée, mais non limitative, du procédé et ses variantes.
Manières de réaliser l'invention Lorsque fon expose une masse de matière synthétique, et en particulier un objet réalisé en un polymère thermofusible, à une source de rayonnement thermique, la montée en température de la masse est progressive et l'on observe, à l'intérieur de ladite masse, un gradient de température défini par une courbe sensiblement linéaire dont la pente est négative. L'application simultanée de vibrations ultrasoniques a pour effet soit de réduire la pente de la courbe, soit de l'annuler, soit de l'inverser.
Dans la pratique, ceci se traduit par une augmentation de la vitesse de transmission de la chaleur à travers la masse de oolvmère. cette augmentation pouvant ëtre telle que la paroi de l'objet éloignée de la source de rayonnement thermique atteint, au bout d'un laps de temps extrêmement court, une température supérieure à celle de la paroi la plus proche.
Pour atteindre ce but, l'on expose le polymère thermofusible simultanément à
au moins une source de rayonnement thermique et à des vibrations ultrasoniques. Pour transmettre ces vibrations au polymère on peut appliquer directement sur une de ses surfaces une sonotrode alimentée par un 3 thermal is between 1 and 10 seconds and preferably approximately 3 seconds.
According to a particularly interesting way of proceeding, one applies-the ultrasonic vibrations intermittently.
This variant also modulates the transmission speed of the heat in the polymer.
The present invention will be better understood from the description of a form of preferred, but not limiting, implementation of the method and its variants.
Ways to realize the invention When fon exposes a mass of synthetic material, and in particular a object made of a hot-melt polymer, to a radiation source thermal, the temperature rise of the mass is gradual and one observes, inside said mass, a temperature gradient defined by a substantially linear curve with a negative slope. The application simultaneous ultrasonic vibration has the effect of either reducing the slope of the curve, either to cancel it, or to reverse it.
In practice, this results in an increase in the speed of transmission of heat through the mass of the egg. this increase may be such that the wall of the object distant from the source of thermal radiation reached, after an extremely short period of time short, a temperature higher than that of the nearest wall.
To achieve this goal, the hot melt polymer is exposed simultaneously to at least one source of thermal radiation and vibrations ultrasonic. To transmit these vibrations to the polymer, we can apply directly on one of its surfaces a sonotrode powered by a
4 générateur d'ultrasons.
Différentes autres variantes de réalisation du procédé peuvent être mises en eeuvre. L'une de ses variantes consiste à exposer une surface du polymère à, une première source de rayonnement thermique, la surface opposée à une seconde source de rayonnement thermique et d'appliquer simultanément des vibrations ultrasoniques.
L'on peut également transmettre les vibrations ultrasoniques indirectement au polymère en mettant la sonotrode en contact avec un liquide intermédiaire qui est en contact avec une surface de ce polymère.
Dans toutes les variantes, les sources de rayonnement ont une température comprise entre 100° et 500° C et la fréquence des vibrations ultrasoniques transmises est comprise entre 15 et 60 kHZ.
On a constaté que pour des produits réalisés en un polymère thermofusible tel que du polyéthylène téréphtalate (PET) ayant quelques millimètres d'épaisseur, 1e temps de l'exposition à une source de rayonnement thermique, nécessaire pour les rendre suffisamment propres à un traitement de thermoformage, est compris entre 1 et 10 secondes et de préférence voisin de 3 secondes.
Par ailleurs ce polyéthylène téréphtalate ne subit aucune cristallisation à
une température égale ou supérieure à la température de transition vitreuse qui est généralement supérieure à 70°C.
Enfin on constate que la structure devient anisotrope et que les chaïnes moléculaires des polymères thermofusibles s'orientent dans une direction préférentielle parallèle à l'axe de propagation des vibrations ultrasoniques.
Ces phénomènes empêchent (arrêt de la propagation des ultrasons dans la matière dès que la transition vitreuse est atteinte.
On améliore encore ces résultats en appliquant les vibrations ultrasoniques de façon intermittente. La direction de Taxe de propagation des vibrations-4 ultrasonic generator.
Different other alternative embodiments of the process can be implemented.
work. One of its variants consists in exposing a surface of the polymer to, a first source of thermal radiation, the surface opposite to a second source of thermal radiation and simultaneously apply ultrasonic vibrations.
The ultrasonic vibrations can also be transmitted indirectly to the polymer by bringing the sonotrode into contact with an intermediate liquid which is in contact with a surface of this polymer.
In all variants, the radiation sources have a temperature between 100 ° and 500 ° C and the frequency of vibrations ultrasonic transmitted is between 15 and 60 kHz.
It has been found that for products produced from a hot-melt polymer such than polyethylene terephthalate (PET) having a few millimeters thickness, the time of exposure to a source of thermal radiation, necessary to make them sufficiently suitable for treatment of thermoforming, is between 1 and 10 seconds and preferably close to 3 seconds.
Furthermore, this polyethylene terephthalate does not undergo any crystallization at a temperature equal to or greater than the glass transition temperature which is generally above 70 ° C.
Finally we see that the structure becomes anisotropic and that the chains molecules of hot melt polymers point in one direction preferential parallel to the axis of propagation of ultrasonic vibrations.
These phenomena prevent (stopping the propagation of ultrasound in the matter as soon as the glass transition is reached.
These results are further improved by applying the ultrasonic vibrations of intermittently. The direction of vibration propagation tax-
5 ultrasoniques est choisie en fonction de la géométrie des objets à
thermoformer. S'il s'agit d'objets allongés, on applique de préférence les ultrasons selon une direction qui correspond à la plus grande longueur de ces objets. L'alignement des chaînes moléculaires s'effectue selon cette direction et favorise la propagation des vibrations ultrasoniques. 5 ultrasonic is chosen according to the geometry of the objects to be thermoform. In the case of elongated objects, the ultrasound in a direction which corresponds to the greatest length of these objects. The alignment of molecular chains takes place in this direction and promotes the propagation of ultrasonic vibrations.
Claims (7)
et 500°C. 4. Method according to claims 1 and 2, characterized in that said thermal radiation sources have a temperature between 100°
and 500°C.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR98/11212 | 1998-09-01 | ||
| FR9811212A FR2782665B1 (en) | 1998-09-01 | 1998-09-01 | PROCESS FOR INCREASING THE THERMAL CONVECTION SPEED IN A HEAT-MELT POLYMER |
| PCT/CH1999/000405 WO2000012279A1 (en) | 1998-09-01 | 1999-09-01 | Method for increasing thermal convection speed in a thermofusible polymer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2341600A1 true CA2341600A1 (en) | 2000-03-09 |
Family
ID=9530234
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002341600A Abandoned CA2341600A1 (en) | 1998-09-01 | 1999-09-01 | Method for increasing thermal convection speed in a thermofusible polymer |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP1109655A1 (en) |
| JP (1) | JP2002523262A (en) |
| CA (1) | CA2341600A1 (en) |
| FR (1) | FR2782665B1 (en) |
| WO (1) | WO2000012279A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030201581A1 (en) * | 2002-02-28 | 2003-10-30 | Jan Weber | Ultrasonic assisted processes |
| GB0811548D0 (en) * | 2008-06-24 | 2008-07-30 | Airbus Uk Ltd | Method and apparatus for fabricating a fibre reinforced thermoplastic composite structure |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2855298A1 (en) * | 1977-12-27 | 1979-07-05 | Bassan & Cie | Thermoplastic screw-holding tube with end flange - the extrusion being moulded into flange at one end by axial pressure |
| JPS5515812A (en) * | 1978-07-19 | 1980-02-04 | Inoue Mtp Co Ltd | Method of working the end of synthetic resin mole having stacked metal foil. |
| GB9414396D0 (en) * | 1994-07-16 | 1994-09-07 | Fairbank David | Bollard refurbishment |
| JP3789145B2 (en) * | 1995-02-07 | 2006-06-21 | 富士写真フイルム株式会社 | Method and apparatus for restoring flatness of belt-like object |
-
1998
- 1998-09-01 FR FR9811212A patent/FR2782665B1/en not_active Expired - Fee Related
-
1999
- 1999-09-01 EP EP99939307A patent/EP1109655A1/en not_active Withdrawn
- 1999-09-01 WO PCT/CH1999/000405 patent/WO2000012279A1/en not_active Application Discontinuation
- 1999-09-01 CA CA002341600A patent/CA2341600A1/en not_active Abandoned
- 1999-09-01 JP JP2000567360A patent/JP2002523262A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JP2002523262A (en) | 2002-07-30 |
| EP1109655A1 (en) | 2001-06-27 |
| FR2782665A1 (en) | 2000-03-03 |
| FR2782665B1 (en) | 2000-11-10 |
| WO2000012279A1 (en) | 2000-03-09 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued | ||
| FZDE | Discontinued |
Effective date: 20030902 |
|
| FZDE | Discontinued |
Effective date: 20030902 |