CN111283946A - Material foaming method for in-mold foaming molding - Google Patents
Material foaming method for in-mold foaming molding Download PDFInfo
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- CN111283946A CN111283946A CN202010103940.9A CN202010103940A CN111283946A CN 111283946 A CN111283946 A CN 111283946A CN 202010103940 A CN202010103940 A CN 202010103940A CN 111283946 A CN111283946 A CN 111283946A
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- plastic particles
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- foaming
- foaming method
- mould
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Classifications
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- 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
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- 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
- B29C44/3403—Foaming under special conditions, e.g. in sub-atmospheric pressure, in or on a liquid
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- 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
- B29C44/3461—Making or treating expandable particles
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- 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
- B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
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- 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
- B29K2105/0005—Condition, form or state of moulded material or of the material to be shaped containing compounding ingredients
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- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
Abstract
A material foaming method for foaming and forming in a mold comprises the following steps: step A, introducing plastic particles into a mold; step B, a pressurizing and heating device pressurizes and heats the mold, if the plastic particles are made of polyolefin materials, the step C is carried out, and if the plastic particles are made of thermoplastic elastomers, the step D is directly carried out; c, performing high-pressure impregnation by using a supercritical fluid in a mould, and impregnating the plastic particles by using the supercritical fluid to obtain the plastic particles impregnated by the supercritical fluid; step D, after pressure relief, the plastic particles are placed in the mold 1: 1, foaming and forming, cooling the mould after foaming and forming, opening the mould after cooling the mould, and taking out a foamed product. The foaming method does not need to use an injection molding machine or an extruder, and simultaneously does not need to arrange a buffer tank, thereby greatly reducing the equipment cost of material foaming. In addition, the foaming method adopts a heating mode, the material is in a molten or softened state during foaming, the foaming efficiency is high, and the plastic particles can be fully foamed and molded.
Description
Technical Field
The invention relates to a physical foaming method, in particular to a material foaming method for foaming and forming in a die.
Background
In the foaming process or the foaming polymer material, a honeycomb or cellular structure is formed through the addition and reaction of a physical foaming agent or a chemical foaming agent. The basic steps of foam molding are the formation of a bubble nucleus, the growth or enlargement of the bubble nucleus, and the stabilization of the bubble nucleus.
Chinese patent CN109517262A discloses a supercritical fluid foaming method with whole pressure maintaining, which is to make plastic particles after permeation in a storage tank, and then to injection mold or extrusion mold the product by an injection molding machine or an extruder. However, the cost of the injection molding machine and the extruder is high and the purchase and overhaul of the equipment will greatly increase the overall cost of the foaming process.
Chinese patent CN110157086A discloses a physical foaming method for directly forming a foamed product in a mold, which puts the mold into a pressure vessel, and when the pressure vessel is relieved, the semi-finished product is directly processed in the mold by 1: 1 foaming. However, the parison obtained by the above-mentioned physical foaming method still needs to be produced by an injection molding machine, an extrusion molding machine or a molding machine, and therefore, the cost reduction of the foaming process is also restricted. Further, the above physical foaming method is carried out at normal temperature by 1: 1, foaming and low foaming efficiency.
Disclosure of Invention
In order to solve the above problems, the present invention provides a material foaming method for foam molding in a mold, the foaming method comprising the steps of:
step A, introducing plastic particles into a mold;
step B, a pressurizing and heating device pressurizes and heats the mold, if the plastic particles are made of polyolefin materials, the step C is carried out, and if the plastic particles are made of thermoplastic elastomers, the step D is directly carried out;
c, performing high-pressure impregnation by using a supercritical fluid in a mould, and impregnating the plastic particles by using the supercritical fluid to obtain the plastic particles impregnated by the supercritical fluid;
step D, after pressure relief, the plastic particles are placed in the mold 1: 1, foaming and forming, cooling the mould after foaming and forming, opening the mould after cooling the mould, and taking out a foamed product.
Further, the supercritical fluid comprises one or more of carbon dioxide, water, methane, ethane, ethylene, propylene, methanol, ethanol, acetone, and nitrogen.
Furthermore, the pressure intensity of high-pressure infiltration is 5-60 MPa, the temperature range is 5 ℃ higher than the softening point of the plastic particles to 3 ℃ lower than the melting point of the plastic particles, and the infiltration duration is 0.5-8 h.
Further, in the step D, the temperature range inside the mold is 25 ℃ lower than the melting point of the plastic particles to 25 ℃ higher than the melting point of the plastic particles, before pressure relief, the pressure range inside the mold is more than 0.1MPa and less than or equal to 40MPa, and the pressure maintaining time is 0.2-5 h; and after pressure relief, the foaming duration is 5-10 min, and the mold is cooled to below 40 ℃ and then opened.
Further, if the plastic pellet is a polyolefin material, before the step a, the following steps are further performed: and E, performing a crosslinking reaction on the plastic particles to obtain crosslinked plastic particles.
Further, in the step E, the crosslinking reaction is performed in a chemical crosslinking manner or an electron beam irradiation manner.
Further, the polyolefin composition comprises a polyolefin material, and the polyolefin composition material is doped with one or more of a cross-linking agent, a filler and an auxiliary agent.
Further, the polyolefin material comprises one or more of ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), Low Density Polyethylene (LDPE), and Ethylene Propylene Diene Monomer (EPDM).
Further, the thermoplastic elastomer comprises one or more of Thermoplastic Polyurethane (TPU), thermoplastic polyester elastomer (TPEE), block polyether amide elastomer (Pebax), Polyethylene (PE), polypropylene (PP).
After the technical scheme is adopted, the invention has the effects that: the foaming method does not need to use an injection molding machine or an extruder, and simultaneously does not need to arrange a buffer tank, thereby greatly reducing the equipment cost of material foaming. In addition, the foaming method adopts a heating mode, the material is in a molten or softened state during foaming, the foaming efficiency is high, and the plastic particles can be fully foamed and molded.
Drawings
FIG. 1 is a schematic view of a foaming apparatus using an autoclave according to the present invention;
fig. 2 is a schematic view of a foaming apparatus using a molding press according to the present invention.
Detailed Description
The technical solution of the present invention is further described by the following examples:
the invention provides a material foaming method for foaming and forming in a mould, as shown in figures 1 and 2, the foaming method uses equipment comprising: storage tank 1, transmission line 2, pressure heater unit 3 and mould 4, transmission line 2's one end and the inside intercommunication of storage tank 1, the other end and the inside intercommunication of mould 4, mould 4 are located pressure heater unit 3 insidely, have valve 20 in the transmission line 2. In the present embodiment, the pressure heating device 3 may be an autoclave or a molding press (also referred to as an oil press). When the pressure heating device 3 is a pressure kettle, the mold 4 is provided with a through hole 40; when the pressure-heating device 3 is a molding press, the molding press has a high-pressure line 30, and the high-pressure line 30 communicates with the inside of the mold 4.
The foaming method comprises the following steps:
step A, opening a valve 20 of a transmission pipeline 2, and guiding plastic particles into a mold 4 from a storage tank 1 through the transmission pipeline 2;
step B, the pressurizing and heating device 3 pressurizes and heats the mold 4, if the plastic particles are made of polyolefin materials, the step C is carried out, and if the plastic particles are made of thermoplastic elastomers, the step D is directly carried out;
c, performing high-pressure impregnation in the mold by using a supercritical fluid, and impregnating the plastic particles with the supercritical fluid through a high-pressure pipeline 30 or a through hole 40 of the mold to obtain the plastic particles impregnated with the supercritical fluid;
step D, after pressure relief, the plastic particles are placed in the mold 4, wherein the pressure relief is performed according to the following steps: 1, foaming and forming, cooling the mould 4 after foaming and forming, opening the mould 4 after cooling (namely separating an upper mould and a lower mould of the mould), and taking out a foamed product.
As a preferred scheme, if the plastic pellet is polyolefin material, before the step a, the following steps are further performed: and E, performing a crosslinking reaction on the plastic particles to obtain crosslinked plastic particles.
The foaming method does not need to use an injection molding machine or an extruder, and simultaneously does not need to arrange a buffer tank, thereby greatly reducing the equipment cost of material foaming. In addition, the foaming method adopts a heating mode, the material is in a molten or softened state during foaming, the foaming efficiency is high, and the plastic particles can be fully foamed and molded.
Introduction of plastic particles
And opening a valve of the transmission pipeline, and guiding the plastic particles into the mold from the storage tank through the transmission pipeline.
The plastic pellets that can be used in the supercritical fluid foaming process of the present invention include polyolefin compositions and thermoplastic elastomers.
The polyolefin composition comprises a polyolefin material, and the polyolefin material is doped with one or more of a cross-linking agent, a filler, and an auxiliary agent. The cross-linking agent can react with the poly-hydrocarbon resin to form a bridge bond between polymer molecular chains and change the polymer molecular chains into insoluble substances with a three-dimensional structure; the filler can improve the material performance, increase the volume and weight and reduce the material cost; the auxiliary agent can improve the fluidity of the main material. Wherein the amount of cross-linking agent may be between 0.15phr and 1.1phr, preferably between 0.25phr and 1.0phr, the amount of filler may be below 30phr and the amount of auxiliary agent may be below 10phr, based on 100phr of polyolefin material.
The polyolefin material may include one or more of ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), Low Density Polyethylene (LDPE), Ethylene Propylene Diene Monomer (EPDM). For example, the polyolefin material can be EVA with a vinyl acetate content of 5-40% by mole, or can be a mixture of EVA/POE with a blending ratio of 100/0.1-0.1/100, or can be a blend of a polyolefin material and a rubber material, such as an EVA/POE/EPDM (ethylene propylene diene monomer) blend with a blending ratio of 100/0.1/0.1-0.1/100/20.
The crosslinking agent may comprise a peroxide, for example comprising one or more of dicumyl peroxide (DCP), di-tert-butylperoxydiisopropylbenzene (BIPB).
The filler can comprise one or more of calcium carbonate, talcum powder, zinc oxide powder and titanium dioxide.
The auxiliary agent can comprise one or more of paraffin and stearic acid.
The thermoplastic elastomer may comprise one or more of Thermoplastic Polyurethane (TPU), thermoplastic polyester elastomer (TPEE), block polyetheramide elastomer (Pebax), Polyethylene (PE), polypropylene (PP).
Pressure and heat
And opening a valve of the transmission pipeline, transmitting the plastic particles to the interior of the mold from the material storage tank through the transmission pipeline, and pressurizing and heating the mold by the interior of the pressurizing and heating device until the pressure and the temperature inside the mold are constant.
Preferably, the pressure and heat apparatus is a molding press. Compared with a pressure kettle, the heating temperature required by the molding press is relatively low and energy is saved because the molding press has fast heat conduction; in addition, the die press has good heat conductivity, so the impregnation time is short, the product is convenient to take, and the production efficiency can be greatly improved.
Impregnation of plastic pellets
And (3) performing high-pressure impregnation by using a supercritical fluid in the mould, and impregnating the plastic particles with the supercritical fluid through a high-pressure pipeline or through holes of the mould to obtain the plastic particles impregnated with the supercritical fluid. Wherein the supercritical fluid may comprise one or more of carbon dioxide, water, methane, ethane, ethylene, propylene, methanol, ethanol, acetone, and nitrogen. The pressure intensity of high-pressure infiltration is 5-60 MPa, the temperature range is 5 ℃ higher than the softening point of the plastic particles to 3 ℃ lower than the melting point of the plastic particles, and the infiltration duration is 0.5-8 h. In the plastic pellet impregnated with the obtained supercritical fluid, the supercritical fluid permeation amount of the plastic pellet is 1 to 10% by weight. When the temperature of high-pressure impregnation is close to the melting point of the raw material, the raw material is in a molten state, and the supercritical fluid cannot be smoothly impregnated; when the temperature of the high-pressure impregnation is close to the softening temperature of the raw material, the raw material assumes a hard state (i.e., too high strength), and the supercritical fluid cannot remain in the raw material.
Claims (10)
1. A material foaming method for foaming and forming in a mold is characterized in that: the foaming method comprises the following steps:
step A, introducing plastic particles into a mold;
step B, a pressurizing and heating device pressurizes and heats the mold, if the plastic particles are made of polyolefin materials, the step C is carried out, and if the plastic particles are made of thermoplastic elastomers, the step D is directly carried out;
c, performing high-pressure impregnation by using a supercritical fluid in a mould, and impregnating the plastic particles by using the supercritical fluid to obtain the plastic particles impregnated by the supercritical fluid;
step D, after pressure relief, the plastic particles are placed in the mold 1: 1, foaming and forming, cooling the mould after foaming and forming, opening the mould after cooling the mould, and taking out a foamed product.
2. The material foaming method for in-mold foam molding according to claim 1, characterized in that: the supercritical fluid comprises one or more of carbon dioxide, water, methane, ethane, ethylene, propylene, methanol, ethanol, acetone, and nitrogen.
3. The material foaming method for in-mold foam molding according to claim 1, characterized in that: the pressure intensity of high-pressure infiltration is 5-60 MPa, the temperature range is 5 ℃ higher than the softening point of the plastic particles to 3 ℃ lower than the melting point of the plastic particles, and the infiltration duration is 0.5-8 h.
4. The material foaming method for in-mold foam molding according to claim 1, characterized in that: in the step D, the temperature range inside the mold is 25 ℃ lower than the melting point of the plastic particles to 25 ℃ higher than the melting point of the plastic particles, the pressure range inside the mold is more than 0.1MPa and less than or equal to 40MPa before pressure relief, and the pressure maintaining time is 0.2-5 h; and after pressure relief, the foaming duration is 5-10 min, and the mold is cooled to below 40 ℃ and then opened.
5. The material foaming method for in-mold foam molding according to claim 1, characterized in that: if the plastic particles are polyolefin material, before the step A, the following steps are further carried out: and E, performing a crosslinking reaction on the plastic particles to obtain crosslinked plastic particles.
6. The material foaming method for in-mold foam molding according to claim 1, characterized in that: the pressurizing and heating device is a molding press.
7. The material foaming method for in-mold foam molding according to claim 1, characterized in that: the polyolefin composition comprises a polyolefin material, and the polyolefin composition material is further doped with one or more of a cross-linking agent, a filler and an auxiliary agent.
8. The material foaming method for in-mold foam molding according to claim 7, wherein: the polyolefin material comprises one or more of ethylene-vinyl acetate copolymer, polyolefin elastomer, low-density polyethylene and ethylene propylene diene monomer.
9. The material foaming method for in-mold foam molding according to claim 7, wherein: the cross-linking agent is peroxide; the filler comprises at least one of calcium carbonate, talcum powder, mica powder, argil, zinc oxide powder and titanium dioxide; the auxiliary agent may comprise at least one of paraffin, stearic acid, zinc salt, calcium salt.
10. The material foaming method for in-mold foam molding according to claim 1, characterized in that: the thermoplastic elastomer comprises one or more of thermoplastic polyurethane, thermoplastic polyester elastomer, block polyether amide elastomer, polyethylene and polypropylene.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010103940.9A CN111283946A (en) | 2020-02-20 | 2020-02-20 | Material foaming method for in-mold foaming molding |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010103940.9A CN111283946A (en) | 2020-02-20 | 2020-02-20 | Material foaming method for in-mold foaming molding |
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| CN111283946A true CN111283946A (en) | 2020-06-16 |
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| CN202010103940.9A Pending CN111283946A (en) | 2020-02-20 | 2020-02-20 | Material foaming method for in-mold foaming molding |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112895307A (en) * | 2021-03-11 | 2021-06-04 | 爱驰汽车有限公司 | Method and equipment for manufacturing spoiler |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040080070A1 (en) * | 2002-10-23 | 2004-04-29 | Industrial Technology Research Institute | Method of manufacturing polymeric foam using supercritical fludis |
| CN107099129A (en) * | 2017-05-05 | 2017-08-29 | 宁波格林美孚新材料科技有限公司 | A kind of moulding process of composite thermoplastic polyurethane elastomer expanded material |
| CN208118254U (en) * | 2018-03-07 | 2018-11-20 | 泉州师范学院 | A kind of macromolecule polymer material supercritical fluid foam device |
-
2020
- 2020-02-20 CN CN202010103940.9A patent/CN111283946A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040080070A1 (en) * | 2002-10-23 | 2004-04-29 | Industrial Technology Research Institute | Method of manufacturing polymeric foam using supercritical fludis |
| CN107099129A (en) * | 2017-05-05 | 2017-08-29 | 宁波格林美孚新材料科技有限公司 | A kind of moulding process of composite thermoplastic polyurethane elastomer expanded material |
| CN208118254U (en) * | 2018-03-07 | 2018-11-20 | 泉州师范学院 | A kind of macromolecule polymer material supercritical fluid foam device |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112895307A (en) * | 2021-03-11 | 2021-06-04 | 爱驰汽车有限公司 | Method and equipment for manufacturing spoiler |
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Application publication date: 20200616 |