CA1053872A - Method and device for the production of articles having a non-cellular smooth skin and a cellular core from polymer materials - Google Patents
Method and device for the production of articles having a non-cellular smooth skin and a cellular core from polymer materialsInfo
- Publication number
- CA1053872A CA1053872A CA201,463A CA201463A CA1053872A CA 1053872 A CA1053872 A CA 1053872A CA 201463 A CA201463 A CA 201463A CA 1053872 A CA1053872 A CA 1053872A
- Authority
- CA
- Canada
- Prior art keywords
- cellular
- temperature
- polymer
- skin
- blowing agent
- 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
- 230000001413 cellular effect Effects 0.000 title claims abstract description 28
- 238000000034 method Methods 0.000 title claims abstract description 18
- 239000002861 polymer material Substances 0.000 title claims abstract description 12
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 7
- 239000004604 Blowing Agent Substances 0.000 claims abstract description 18
- 229920000642 polymer Polymers 0.000 claims abstract description 14
- 238000002347 injection Methods 0.000 claims abstract description 12
- 239000007924 injection Substances 0.000 claims abstract description 12
- 238000000354 decomposition reaction Methods 0.000 claims abstract description 11
- 238000001746 injection moulding Methods 0.000 claims abstract description 8
- 238000010438 heat treatment Methods 0.000 claims abstract description 6
- 239000006260 foam Substances 0.000 claims abstract description 4
- 238000005485 electric heating Methods 0.000 claims description 4
- 239000000463 material Substances 0.000 description 7
- 230000015572 biosynthetic process Effects 0.000 description 5
- 238000005187 foaming Methods 0.000 description 2
- 239000011888 foil Substances 0.000 description 1
- 230000007246 mechanism Effects 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
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/02—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles
- B29C44/04—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles consisting of at least two parts of chemically or physically different materials, e.g. having different densities
- B29C44/0407—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles consisting of at least two parts of chemically or physically different materials, e.g. having different densities by regulating the temperature of the mould or parts thereof, e.g. cold mould walls inhibiting foaming of an outer layer
-
- 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
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/04—Condition, form or state of moulded material or of the material to be shaped cellular or porous
- B29K2105/043—Skinned foam
Abstract
ABSTRACT OF THE DISCLOSURE:
A method for the production of articles having a non-cellular smooth skin and a cellular core from polymer materials which contain blowing agents, by injection molding. The method of the invention comprises heating the polymer material to a temperature lower than the decomposition temperature of the blowing agent as the polymer material flows through an injection nozzle and into a mold cavity to form a non-cellular skin, abruptly increasing the temperature of the flowing polymer melt to above the decomposition temperature of the blowing agent to cause the polymer to foam and to form a cellular core and thereafter reducing the temperature of the flowing polymer melt to below the decomposition temperature of the blowing agent to complete the non-cellular skin in the area of the injection nozzle.
A method for the production of articles having a non-cellular smooth skin and a cellular core from polymer materials which contain blowing agents, by injection molding. The method of the invention comprises heating the polymer material to a temperature lower than the decomposition temperature of the blowing agent as the polymer material flows through an injection nozzle and into a mold cavity to form a non-cellular skin, abruptly increasing the temperature of the flowing polymer melt to above the decomposition temperature of the blowing agent to cause the polymer to foam and to form a cellular core and thereafter reducing the temperature of the flowing polymer melt to below the decomposition temperature of the blowing agent to complete the non-cellular skin in the area of the injection nozzle.
Description
0S387;2 This invention relates to a method and a device for the production of articles with a non-cellular smooth skin and a cellular core from polymer materials, which contain blowing agents, by injection molding.
Several methods are known for the production of such articles with a smooth skin. In one of them, a preformed deep-drawn foil is placed in the mold cavity to form the skin before filling it with expanding polymer melt. In anothèr method, the mold cavity is completely filled under high pressure with polymer 10 melt, and after the formation of a non-cellular skin the mold is -opened up at such a distànce as to crea-te an additional volume for the foaming of the material in the interior. However,the application of these methods is limited only to articles of specific shapes.
Other methods are known, in which a material which does not contain a blowing agent is used for the formation of the non-cellular skin, while a material without a blowing agent is ~ -used for the cellular core. A general disadvantage of these methods is the necessity of additional injection and distributing units, as well as of additional mechanisms to drive them.
Another method is known, in which a gas pressure is produced in advance in the mold cavity in order to prevent any foaming of the polymer melt when it fills the mold. This method provides a possibility to control the process of structure formation and to obtain articles with a non-cellular skin of uniform thickness. To achieve this, it is necessary to add to ;
the injection molding machines a aistributing unit and a vertical cylinder with piston, which are provided with driving and heating devices.
It is therefore a general object of the invention to avoid the disadvantages of the known methods and devices and to provide a method and device for the production of articles having a non-cellular smooth skin and a cellular core from ' -- 1 -- ~ , ,.
~A , .
- . , . . . . . . . . . . -0538~Z
polymer materials containing blowing agents, by injection molding.
The method of the invention comprises heating the polymer material to a temperature lower than the decomposition temperature of the blowing agent as the polymer material flows through an injection nozzle and into a mold cavity to form a non-cellular skin, abruptly increasing the temperature of the flowing polymer melt to above the decomposition temperature of the blowing agent to cause the polymer to foam and to form a cellular core and thereafter reducing the temperature of the flowing polymer melt to below the decomposition temperature of the blowing agent to complete the non-cellular skin in the area of the injection nozzle.
The invention also provides an injection molding device suitable for carrying out the above method, wherein the injection nozzle has along its axis an electric heatihg element which t consists of a resistive wire connected to a supply and control block; the resistive wire extends substantially over the entire length of the nozzle.
For a better understanding of the invention, reference shall be made to the accompanying drawing in which there is illustrated a preferred embodiment of the invention. The drawing shows a diagrammatical cross-section through an injection nozzle.
The nozzle illustrated consists of two components 1 and 5, which are connected by the nut 4 and are electrically insulated by means of the rings 3. In the axis of the nozzle hole, there is an electric heating element 2 in the form of a resistive wire. -One end of this element is welded to the component 1, while the other end is welded to the component 5. The switching-on and switching-off of the heating element is performed by the supply 30' and control block 7. The nozzle can be attached to the end of the plastificating-injection unit 6 of the injection molding machine.
Several methods are known for the production of such articles with a smooth skin. In one of them, a preformed deep-drawn foil is placed in the mold cavity to form the skin before filling it with expanding polymer melt. In anothèr method, the mold cavity is completely filled under high pressure with polymer 10 melt, and after the formation of a non-cellular skin the mold is -opened up at such a distànce as to crea-te an additional volume for the foaming of the material in the interior. However,the application of these methods is limited only to articles of specific shapes.
Other methods are known, in which a material which does not contain a blowing agent is used for the formation of the non-cellular skin, while a material without a blowing agent is ~ -used for the cellular core. A general disadvantage of these methods is the necessity of additional injection and distributing units, as well as of additional mechanisms to drive them.
Another method is known, in which a gas pressure is produced in advance in the mold cavity in order to prevent any foaming of the polymer melt when it fills the mold. This method provides a possibility to control the process of structure formation and to obtain articles with a non-cellular skin of uniform thickness. To achieve this, it is necessary to add to ;
the injection molding machines a aistributing unit and a vertical cylinder with piston, which are provided with driving and heating devices.
It is therefore a general object of the invention to avoid the disadvantages of the known methods and devices and to provide a method and device for the production of articles having a non-cellular smooth skin and a cellular core from ' -- 1 -- ~ , ,.
~A , .
- . , . . . . . . . . . . -0538~Z
polymer materials containing blowing agents, by injection molding.
The method of the invention comprises heating the polymer material to a temperature lower than the decomposition temperature of the blowing agent as the polymer material flows through an injection nozzle and into a mold cavity to form a non-cellular skin, abruptly increasing the temperature of the flowing polymer melt to above the decomposition temperature of the blowing agent to cause the polymer to foam and to form a cellular core and thereafter reducing the temperature of the flowing polymer melt to below the decomposition temperature of the blowing agent to complete the non-cellular skin in the area of the injection nozzle.
The invention also provides an injection molding device suitable for carrying out the above method, wherein the injection nozzle has along its axis an electric heatihg element which t consists of a resistive wire connected to a supply and control block; the resistive wire extends substantially over the entire length of the nozzle.
For a better understanding of the invention, reference shall be made to the accompanying drawing in which there is illustrated a preferred embodiment of the invention. The drawing shows a diagrammatical cross-section through an injection nozzle.
The nozzle illustrated consists of two components 1 and 5, which are connected by the nut 4 and are electrically insulated by means of the rings 3. In the axis of the nozzle hole, there is an electric heating element 2 in the form of a resistive wire. -One end of this element is welded to the component 1, while the other end is welded to the component 5. The switching-on and switching-off of the heating element is performed by the supply 30' and control block 7. The nozzle can be attached to the end of the plastificating-injection unit 6 of the injection molding machine.
- 2 -,.
` lOS31~
When utilizing such injection nozzle, the process of the invention is as follows: ~
Polymer melt, heated to a temperature lower than the ;
decomposition temperature of the blowing agent is injected into -the mold cavity. After a predetermined quantity of material that is necessary for the formation of the non-cellular skin has been introduced into the mold, the electric heating element 2 in the nozzle is then switched-on/ thus abruptly increasing the temperature of the polymer melt which is flowing through to above the decomposition temperature of the blowing agent. This latter material fills up the core portion Gf the molded article. This `
heating continues until a predetermined quantity of foamed material which is necessary for the formation of the cellular core has been introduced into the mold. At the end of the filling, the electric heating element 2 is switched-off in order to reduce the temperature so that the last portion of material cannot foam, in order to obtain a non-cellular surface in the area of the sprue.
. _ 3 _ '
` lOS31~
When utilizing such injection nozzle, the process of the invention is as follows: ~
Polymer melt, heated to a temperature lower than the ;
decomposition temperature of the blowing agent is injected into -the mold cavity. After a predetermined quantity of material that is necessary for the formation of the non-cellular skin has been introduced into the mold, the electric heating element 2 in the nozzle is then switched-on/ thus abruptly increasing the temperature of the polymer melt which is flowing through to above the decomposition temperature of the blowing agent. This latter material fills up the core portion Gf the molded article. This `
heating continues until a predetermined quantity of foamed material which is necessary for the formation of the cellular core has been introduced into the mold. At the end of the filling, the electric heating element 2 is switched-off in order to reduce the temperature so that the last portion of material cannot foam, in order to obtain a non-cellular surface in the area of the sprue.
. _ 3 _ '
Claims (2)
1. A method for the production of articles having a non-cellular smooth skin and a cellular core from polymer materials which contain blowing agents, by injection molding, which comprises heating the polymer material to a temperature lower than the decomposition temperature of the blowing agent as the polymer material flows through an injection nozzle and into a mold cavity to form a non-cellular skin, abruptly increasing the temperature of the flowing polymer melt to above the decomposition temperature of the blowing agent to cause the polymer to foam and to form a cellular core and thereafter reducing the temperature of the flowing polymer melt to below the decomposition temperature of the blowing agent to complete the non-cellular skin in the area of the injection nozzle.
2. In an injection molding device for the production of articles having a non-cellular smooth skin and a cellular core from polymer materials which contain blowing agents, an injection nozzle having along its axis an electric heating element which consists of a resistive wire connected to a supply and control block, said resistive wire extending substantially over the entire length of the nozzle.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| BG23557A BG18676A1 (en) | 1973-05-09 | 1973-05-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1053872A true CA1053872A (en) | 1979-05-08 |
Family
ID=3899438
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA201,463A Expired CA1053872A (en) | 1973-05-09 | 1974-06-03 | Method and device for the production of articles having a non-cellular smooth skin and a cellular core from polymer materials |
Country Status (12)
| Country | Link |
|---|---|
| JP (1) | JPS51576A (en) |
| AT (1) | AT353471B (en) |
| BE (1) | BE814758A (en) |
| BG (1) | BG18676A1 (en) |
| CA (1) | CA1053872A (en) |
| DD (1) | DD111323A5 (en) |
| DE (1) | DE2422579A1 (en) |
| FR (1) | FR2228598B1 (en) |
| GB (1) | GB1460101A (en) |
| IT (1) | IT1035534B (en) |
| NL (1) | NL7406286A (en) |
| SE (1) | SE402547B (en) |
Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4457511A (en) * | 1982-03-15 | 1984-07-03 | William Witkowski | Plastic bowling pin and method of making the same |
| GB2139548B (en) * | 1983-05-11 | 1986-11-19 | James Watson Hendry | Injection moulding |
| IT1212799B (en) * | 1983-12-15 | 1989-11-30 | Ates Componenti Elettron | ELECTRONIC DEVICE WITH CONTROLLED SWITCH FOR THE SUPPRESSION OF TRANSITORS. |
| US4935191A (en) * | 1986-10-16 | 1990-06-19 | Thomas W. Johnson | Process of insection molding with pressurized gas assist |
| GB8706204D0 (en) * | 1987-03-16 | 1987-04-23 | Peerless Cinpres Ltd | Injection moulding apparatus |
| US5032345A (en) * | 1987-07-09 | 1991-07-16 | Michael Ladney | Method of injection molding with pressurized-fluid assist and variable-volume reservoir |
| US4943407A (en) * | 1987-09-21 | 1990-07-24 | Michael Ladney | Method of and apparatus for injection molding with pressurized fluid assist |
| US4855094A (en) * | 1987-09-21 | 1989-08-08 | Michael Ladney | Method for the injection molding of plastic articles using fluid pressure |
| US5069859A (en) * | 1987-12-16 | 1991-12-03 | Milad Limited Partnership | Method of injection molding with pressurized-fluid assist |
| US4830812A (en) * | 1988-04-15 | 1989-05-16 | Michael Ladney | Method and system for making a hollow-shaped body from molten resin by injection molding |
| US4913644A (en) * | 1988-04-15 | 1990-04-03 | Michael Ladney | System for making a hollow-shaped body from molten resin by injection molding |
| US5098637A (en) * | 1988-07-11 | 1992-03-24 | Milad Limited Partnership | Process for injection molding and hollow plastic article produced thereby |
| US6053720A (en) * | 1997-09-22 | 2000-04-25 | Larry J. Winget | Mold for use in a gas-assisted injection molding system and gas pin assembly for use therein |
| US6767487B2 (en) | 2001-07-10 | 2004-07-27 | Cinpres Gas Injection Ltd. | Plastic expulsion process |
| US6890477B2 (en) | 2003-03-25 | 2005-05-10 | Lear Corporation | Plastic injection molded articles with hollow rib members |
| US6899843B2 (en) | 2003-03-25 | 2005-05-31 | Lear Corporation | Plastic injection molding with moveable mold members forming speaker grill |
| CN104647679B (en) * | 2013-11-22 | 2018-07-17 | 法国圣戈班玻璃公司 | Form method, vehicle window and the mold of automobile glass encapsulation |
-
1973
- 1973-05-09 BG BG23557A patent/BG18676A1/xx unknown
-
1974
- 1974-05-07 IT IT7450620A patent/IT1035534B/en active
- 1974-05-08 AT AT381174A patent/AT353471B/en active
- 1974-05-08 DD DD178369A patent/DD111323A5/xx unknown
- 1974-05-08 SE SE7406168A patent/SE402547B/en unknown
- 1974-05-08 FR FR7415901A patent/FR2228598B1/fr not_active Expired
- 1974-05-09 DE DE2422579A patent/DE2422579A1/en not_active Withdrawn
- 1974-05-09 NL NL7406286A patent/NL7406286A/xx unknown
- 1974-05-09 BE BE2053599A patent/BE814758A/en unknown
- 1974-05-09 GB GB2065074A patent/GB1460101A/en not_active Expired
- 1974-06-03 CA CA201,463A patent/CA1053872A/en not_active Expired
- 1974-06-21 JP JP49071233A patent/JPS51576A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| FR2228598A1 (en) | 1974-12-06 |
| BG18676A1 (en) | 1975-03-20 |
| SE402547B (en) | 1978-07-10 |
| JPS51576A (en) | 1976-01-06 |
| DE2422579A1 (en) | 1974-11-28 |
| DD111323A5 (en) | 1975-02-12 |
| JPS534873B2 (en) | 1978-02-21 |
| FR2228598B1 (en) | 1976-10-15 |
| GB1460101A (en) | 1976-12-31 |
| IT1035534B (en) | 1979-10-20 |
| NL7406286A (en) | 1974-11-12 |
| AT353471B (en) | 1979-11-12 |
| BE814758A (en) | 1974-09-02 |
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