WO2018222089A1

WO2018222089A1 - Device for thermally molding molten polymer or resin by injection molding, and injection mold thereof

Info

Publication number: WO2018222089A1
Application number: PCT/RU2018/000355
Authority: WO
Inventors: Александр Андреевич МАКСИМОВ
Original assignee: Александр Андреевич МАКСИМОВ
Priority date: 2017-06-02
Filing date: 2018-05-31
Publication date: 2018-12-06
Also published as: RU2643562C1

Abstract

A device for thermally molding a molten polymer or a resin by injection molding consists of a cylindrical melting chamber equipped with a heater, and a piston disposed therein so as to be translatable along the axis of the chamber. The melting chamber and an injection mold are situated inside of a separable sealed casing, the inner cavity of which is connected to a fore-vacuum pump. The inner cavity of the injection mold communicates with the inner cavity of the sealed casing, and the melting chamber, the piston, and the injection mold are made of an aluminum-bearing alloy. The injection mold consists of a casing with a vertical plane of separation, a lower cover with an aperture for admitting the molten polymer and with a quick-release means of being fastened to the melting chamber, and an upper cover with an aperture for releasing excess polymer. Both covers are conical inside of the mold cavity and at their perimeter are disposed in annular grooves formed in the casing, and the separable sections of the casing are joined by at least one adjustable clamping band situated on the outer surface of the casing.

Description

DEVICE FOR THERMAL FORMING OF MELTED POLYMER OR RESIN WITH PRESSURE MOLDING AND INJECTION MOLD

FOR THE INDICATED DEVICE

Technical field

The group of inventions relates to equipment for processing plastics or resins and can be used in medicine, as well as in food, chemical and other industries.

State of the art

Known injection melting press (Application US2007 / 0194474, B23C 45/76, 2007) for molding molten polymer and / or resin by injection molding (injection press), including a forming chamber of a cylindrical shape and a piston located inside this chamber with the possibility of movement. The piston divides the cylinder into two chambers: retraction and extrusion. The pump and the device for creating pressure along the axis are connected to the extrusion chamber. The sensor measures the pressure in the extrusion chamber. The controller receives signals from the sensor and controls the pump. The pump delivers hydraulic fluid to the extrusion chamber to squeeze and inject (inject) the polymer / resin, placed in the cartridge of easily deformable material, such as aluminum foil, into the cavity of the injection mold by means of a piston. The controller stops the pump when the pressure in the extrusion chamber reaches the set shutdown level. The axial pressure generating device creates a back pressure on the liquid in the extrusion chamber after the controller stops the pump to provide excess pressure on the injected polymer.

The disadvantages of the known device are:

- the technological complexity associated with the need to use a cartridge of easily deformable material, such as aluminum, to accommodate the polymer / resin;

- the inability to reuse the polymer / resin due to mixing with crumpled metal after the end of the casting process; - poor product quality due to melting in the presence of air - the presence of voids containing gas inclusions in the polymer / resin volume after cooling;

- the formation of toxic chemical compounds in the polymer due to the reaction of the polymer melt released from the melt of fumes and air gases that are not removed by melting in the open air (tables 1 and 2);

- insufficient filling of the volume of the cavity of the melting chamber with polymer / resin, since a cartridge occupies part of its volume.

Closest to the claimed device in technical essence is a device for thermal molding of molten polymer / resin by injection under pressure, consisting of a cylindrical molding chamber, inside of which a piston is placed on the rod with the ability to move along the chamber axis from the inlet to the outlet, while the piston divides the molding the chamber into two cavities: the rod cavity and the piston cavity. A disc is located between the piston and the outlet of the molding chamber to protect the piston surface from polymer / resin melt. The outlet of the molding chamber is connected to the volume of the cavity of the injection mold into which the molten polymer is fed by moving the piston. A pressure sensor connected to the input of the controller containing a microprocessor connected to a device for moving the piston is connected to the piston cavity of the molding chamber (RU133772, В29С 45/12, 2013). This technical solution is taken as a prototype. A distinctive feature of the prototype is that the piston interacts with the polymer directly or through a disk with the ability to extrude the polymer / resin through the outlet from the volume of the molding chamber into the cavity of the injection mold, while the roughness of the outer surface of the piston and the inner surface of the molding chamber to move it is in the range of values 1, 0-10-6 mm <Ra <l, 0 mm, where Ra is the arithmetic mean deviation. The gap between the outer surface of the piston and the inner surface of the molding chamber for its movement is in the range of 2.0-10-6 mm <h <l, 0 mm. The injection mold for supplying polymer to the cavity volume has at least one channel opening connecting the volume of the injection mold cavity with a vacuum device. To the volume of the cavity of the injection mold is connected via at least one pressure sensor connected to the controller. Electric heaters and temperature sensors are placed outside the molding chamber and the injection mold, while the temperature sensors of the molding chamber and the injection mold are connected to a controller connected to a vacuum device and devices for regulating the current value in electric heaters.

Although in the design of the prototype, due to evacuation, it was possible to significantly reduce the concentration of air gases in the injection mold, however, the concentration of toxins (tables 1 and 2) directly in the polymer mass could not be reduced, since the polymer melted in the molding chamber in a closed volume, without removing toxic fumes.

Known injection mold (RU133772, B29C 45/12, 2013), including a heated housing with an inlet and shutter elements that overlap the inlet and channels of the means of vacuum.

The disadvantages of the known injection mold are:

- removal of excess polymer / resin from the injection mold through the channel, which must be changed or cleaned after each casting;

- the mold is equipped with a heater, which greatly complicates and increases the time of the preparation process for casting, which increases the time of the technological cycle of the entire casting process.

The closest in technical essence to the claimed one is the injection mold IvoBase-System, the design of which is presented on the Internet at:

https: //drive.google.eom/file/d/0BwDQLK4j5VNcYWhXdzB2RmxwVGs/view.

Injection mold consists of a hollow body with a vertical plane of the connector. Moreover, holes are made on the detachable parts of the housing for loading the forming material into the mold. This design was chosen as a prototype.

The disadvantages of the prototype injection mold are the following factors: - when preparing the mold, it is necessary to manufacture additional gate channels for air removal, which complicates the preparation of the mold for casting and its unpacking after casting; - the enclosed space of the mold leaves the possibility of the formation of porosity of the product due to incomplete exit of air from the mold during casting;

- the form has an angular shape, massive dimensions and weight, which is not convenient during operation;

- when removing the finished product requires the use of physical force or an additional mechanical device.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a device for thermally molding a molten polymer or resin by injection molding, as well as an injection mold devoid of these drawbacks. The technical result is to improve performance and improve product quality.

The problem, as well as the achievement of the claimed technical result, is solved by the proposed device for thermal molding of molten polymer or resin by injection molding, consisting of a cylindrical melting chamber equipped with a heater, inside which a piston is placed with the possibility of movement along the chamber axis, and an injection mold. In this case, the internal cavity of the injection mold by means of a sealed detachable connection communicates with the internal cavity of the melting chamber. A distinctive feature of the proposed device is that the melting chamber with an injection mold is located inside a detachable sealed enclosure, the internal cavity of which is connected to the foreline pump. The internal cavity of the injection mold communicates with the internal cavity of the sealed housing, and the melting chamber, piston and injection mold are made of aluminum-containing alloy.

In addition, it is proposed that the surface of the injection mold adjacent to the melting chamber at the place of detachable connection be made in the form of a confuser, and the outer surface of the piston in contact with polymer or resin should be made in the form of a cone and congruent surface of the confuser. In this case, the piston can be made integral and contain cylindrical and conical detachable parts provided with a circumference a gasket made of graphite-containing or glass-containing insulating material.

In addition, it is proposed that the melting chamber, the cylindrical and conical parts of the piston and the injection mold be made of duralumin.

To solve the technical problem, as well as to achieve a technical result, an injection mold in the form of a cylinder is proposed, consisting of a housing with a vertical plane of the connector, upper and lower covers, together creating a cavity for placing the forming material inside the mold. Moreover, holes are made on the detachable parts of the housing for loading the forming material into the mold. A distinctive feature of the proposed injection mold is that the lower cover is made with an opening for supplying molten polymer and with quick-release means for attaching to the melting chamber, the upper cover is made with an opening for the exit of excess polymer. Both covers along the perimeter are placed in annular grooves made in the housing, and the detachable parts of the housing are combined by at least one adjustable crimp clamp located on the outer surface of the housing.

Additionally, it is proposed that the surfaces of the lids facing the inner cavity of the mold be tapered.

It is also additionally proposed that quick-detachable fastening means be made in the form of a nozzle cantilever-made on the lid, in the wall of which at least one bayonet groove is made.

The location of the melting chamber with the injection mold inside the detachable sealed housing, the internal cavity of which is connected to the foreline pump, while the internal cavity of the injection mold communicates with the internal cavity of the sealed housing, and the melting chamber, the piston and the injection mold are made of aluminum-containing alloy, allow for the conclusion air and all gases emitted during melting during the entire melting time from heating to molding with a simultaneous decrease in the adhesion of the molten polymer or resin to the walls of the melting chamber, and the forming material to the walls of the injection mold. All these factors lead to a significant increase in the quality of products, allow to save material due to the secondary use of residues, greatly simplify and reduce the process of polymer casting. The implementation of the lower cover of the injection mold with an opening for supplying molten polymer and with a quick-detachable means of attachment to the melting chamber, and the upper cover with an opening for the exit of excess polymer allows not to produce air gates when forming the blank of the future product and prevents the occurrence of porosity of the product caused by the remaining air in the cavity forms. The placement of both covers along the perimeter in the annular grooves made in the housing with the simultaneous union of the detachable parts of the housing with at least one adjustable crimp clamp located on the outer surface of the housing allows you to quickly and effortlessly disassemble the form, clean its surfaces and the resulting product from residues forming material. All of these factors increase the quality of products, greatly simplify the process and provide a large guarantee of high-quality full casting of the product and polymer savings.

Embodiments of the invention

The invention is further illustrated by examples of specific performance and drawings, in which:

In FIG. 1 is a schematic cross-sectional view of an apparatus for thermally molding a molten polymer or resin by injection molding,

in FIG. 2 — injection mold assembly,

in FIG. 3 is a plan view of the detachable part of the mold body; FIG. 4 - an enlarged external element of the annular groove, in FIG. 5 is a cross-sectional view of the detachable part of the mold body; FIG. 6 - the appearance of the bottom cover of the injection mold

Fig.7 is a cross section of the lower cover of the injection mold,

in FIG. 8 and 9 are a transverse section and an external element of the upper mold cover.

The proposed device consists of a heater 1, a melting chamber 2, a piston 3, an injection mold body 4, a quick-detachable fastener 5, a detachable sealed housing 6, a foreline pump 7, a confuser 8, a piston cone part 9, a piston cylindrical part 10, and holes 1 1 on detachable parts of the housing, the upper cover 12 injection mold, the lower cover 13 injection molds, holes 14 for supplying molten polymer, holes 15 for exiting excess polymer, annular grooves 16, crimp clamp 17, conical surfaces 18 of the caps facing the inner cavity of the mold, pipe 19 with a bayonet groove, gaskets 20 made of graphite-containing or glass-containing insulating material.

Devices work as follows. A volumetric full-scale model of the finished product is made of fusible material. One of the detachable parts of the body of the injection mold 4 is placed on the table with the open part upwards and the upper 12 and lower 13 of the injection mold cover are inserted into the annular grooves 16 with the conical surfaces 18 inward. A mold-forming self-hardening material is placed in the liquid phase in the thus obtained open container, and a model of the finished product is immersed in it approximately half the volume. Excess mold material is removed to the plane of the connector. In the openings of the covers 14 and 15 are placed the elements of the gate system made of fusible material. The forming material is self-curing. The connector plane of the forming material and the protruding surface of the model are coated with a composition that protects from adhesion. The resulting prefabricated element is covered with the second part of the mold body 4 and the mold body is fastened with crimp clamps 17. Through the open hole 1 1 of the second part of the mold body 4, molding material is fed into the mold until the mold body is completely filled 4. After the mold is solidified, the model is melted by increasing the temperature of the mold to a value exceeding the melting temperature of the fusible material of the model and the gating system, for example, by immersion injection molding rmy in hot water for several minutes. The injection mold is disassembled, the mold is cleaned of residues of the model material and collected again.

When the upper part of the detachable sealed housing 6 is removed, a polymer or resin is placed in the volume of the melting chamber 2 above the conical part 9 of the piston 3. To the melting chamber 2 by means of quick-detachable fastening means, for example a bayonet connector 5, the prepared injection mold is attached. Then the upper part of the detachable sealed housing 6 is connected to the lower part. Heater 1 and foreline pump 7 are turned on. After obtaining a homogeneous polymer or resin melt, piston 3 raise up to the tight fit of the conical part 9 of the piston 3 to the surface of the confuser 8. In this case, the gaskets 20 prevent the penetration of liquid polymer beyond the lower boundary of the cylindrical part of the piston 10, and the molten polymer or resin enters the internal cavity of the injection mold, without encountering obstacles, fill all the mold cavity through the hole 14, and the excess polymer or resin leaves through the hole 15. Next, turn off the heater 1, wait for the product to cure and turn off the foreline pump 7. After removing the upper part releasable encapsulation housing 6 is detached mold, dismantle the housing 4 and the finished product is recovered which is purified by fin and transmitting the final processing.

Industrial applicability

The proposed invention can be used in medicine, food, chemical and other industries, where the processing of plastics or resins is carried out by molding.

Table 1

table 2

3. Polyamides

Tempera Process Main Interaction Product in the matrix of the round ° С volatile with the matrix

product

100 Glass transition no - -

200-250 Melting no - -

300 Hydrolysis, Carbon Dioxide, Crosslinking Education

oxidation of water, ammonia crosslinked polymer

350 Hydrolysis, Carbon Dioxide, Crosslinking Education

oxidation of water, ammonia crosslinked polymer

400 Hydrolysis, Carbon Dioxide, Crosslinking Education

oxidation of water, ammonia crosslinked polymer

4. Polymethylmethacrylates

100 Glass transition no - -

160 No melting - -

200 Depolymeri- Methyl methacry- Oxidation Peroxyacidation of lat groups, anhydride groups, lactones

250 Depolymerization Methyl methacry- Oxidation Peroxyacids, lat, groups, methyl pyruvate cleavage, side chain anhydrides carbon dioxide groups, lactones

300 Methyl Methacry Depolymerization - Peroxy Acid Oxidation

Cia, lat, groups, methyl pyruvate cleavage, carbon chain anhydride side groups, lactones

350 Depolymerization Methyl methacry- Oxidation Peroxyacids, lat, groups, methyl pyruvate cleavage, side chain anhydride carbon dioxide groups, lactones

400 Depolymerization Methyl methacry- Oxidation Peroxyacid, lat, groups, methyl pyruvate cleavage, side chain anhydrides carbon dioxide groups, lactones

5. Polyacetaldehydes

150 Melting Acetaldehyde, Crosslinking Crosslinked fraction of water, butene-2-al

200 Depolymerization Acetaldehyde, Crosslinking Crosslinked fraction

Cia, water, butene-2- al dehydration

250 Depolymerization Acetaldehyde, No Destruction

cation, water, butene-2-matrix

dehydration al

Claims

CLAIM

1. Device for thermoforming molten polymer or resin by injection molding, consisting of a cylindrical melting chamber equipped with a heater, inside of which a piston is placed with the possibility of movement along the chamber axis, and an injection mold, the internal cavity of the injection mold being connected via an internal quick-release means to the internal cavity of the melting chamber, characterized in that the melting chamber with an injection mold is located inside a detachable sealed enclosure, the inner floor st is coupled to the backing pump, the inner mold cavity communicates with the interior of the sealed housing, and a melting chamber, the piston and mold made of an aluminum-containing alloy.

2. The device according to p. 1, characterized in that the surface of the injection mold adjacent to the melting chamber in the place of detachable connection is made in the form of a confuser, and the outer surface of the piston in contact with polymer or resin is made in the form of a cone and congruent to the surface of the confuser .

3. The device according to p. 2, characterized in that the piston is made integral and contains a cylindrical and conical detachable parts, equipped with a gasket of graphite-containing or glass-containing insulating material.

4. The device according to p. 2, characterized in that the melting chamber, cylindrical and conical detachable parts of the piston, and the injection mold are made of duralumin.

5. The injection mold for the device according to claim 1, consisting of a hollow body with a vertical plane of the connector, and on the detachable parts of the housing holes are made for loading the forming material into the mold, characterized in that the injection mold further includes a top and bottom covers, the bottom cover is made with an opening for supplying molten polymer and with quick-release means for attaching to the melting chamber, the top cover is made with an opening for the exit of excess polymer, both covers are placed around the perimeter evy grooves made in the housing, and detachable parts of the housing are combined, at least at least one adjustable crimp clamp located on the outer surface of the housing.

6. The injection mold according to claim 5, characterized in that the surfaces of the lids facing the inner cavity of the mold are conical.

7. The injection mold according to claim 5, characterized in that the quick-detachable fastening means is made in the form of a console nozzle made on the lid, in the wall of which at least one bayonet groove is made.