TW202027959A - Hot extrusion process employing two cooling steps to obtain continuous and elongated body with better curing level and stabler forming shape - Google Patents

Abstract

A hot extrusion process includes: using an extruder to extrude a plastic material to form a continuous and elongated body; performing a first cooling step on the continuous and elongated body in a first cooling region; and, performing a second cooling step on the continuous and elongated body in a second cooling region. The hot extrusion process of the present invention includes two cooling steps, so as to obtain the continuous and elongated body with better curing level and stabler forming shape.

Description

Hot extrusion process

The present invention is related to the hot extrusion molding process; in particular, it refers to a hot extrusion molding process with a secondary cooling step.

In the traditional hot extrusion molding process, after the liquid (or molten) plastic is passed through the mold opening, it usually needs to be cooled and shaped. However, the cooling method of the traditional hot extrusion molding process may be because the cooling rate is too slow, causing the extruded product to be deformed by gravity; or, because the cooling rate is too fast, the extrusion molding product may be incompletely solidified or produced crack. For example, the types of plastics suitable for the traditional hot extrusion molding process are limited by the fluidity and viscosity of the plastic after liquefaction; if the fluidity of the plastic after liquefaction is too high or the viscosity is too low, the product structure of the hot extrusion molding will result It collapses and deforms, so the types of plastics suitable for traditional hot extrusion molding processes usually need to have low fluidity and high viscosity after liquefaction. In short, the types of plastics that can be used in the traditional hot extrusion molding process will be limited by the above-mentioned problems and cannot be widely used.

Because the traditional hot extrusion molding process has the above problems and is not perfect, it is still necessary to propose other novel hot extrusion molding processes to overcome the above problems.

In view of this, the purpose of the present invention is to provide a hot extrusion molding process that includes a secondary cooling step to obtain a continuous elongated body with a better solidification degree and a more stable shape. The secondary cooling step can avoid the problem of incomplete solidification or cracks caused by rapid cooling of liquid plastics.

In order to achieve the above objective, a hot extrusion molding process provided by the present invention includes: using an extrusion molding machine to extrude plastic to form a continuous elongated body; using a first cooling zone to perform a first cooling step on the continuous elongated body; And using the second cooling zone, the continuous elongated body is subjected to the second cooling step.

According to an embodiment of the present invention, the first cooling step is to cool the continuous elongated body from a liquid state to a semi-solid state.

According to an embodiment of the present invention, the temperature of the first cooling zone is constant temperature or gradient temperature drop.

According to an embodiment of the present invention, the temperature of the first cooling zone decreases gradually with the distance between the first cooling zone and the extrusion molding machine.

According to an embodiment of the present invention, the temperature of the first cooling zone is reduced from the temperature of the die outlet of the extrusion molding machine to a first temperature, and the first temperature is lower than the temperature of the die outlet.

According to an embodiment of the present invention, the second cooling step is to cool the continuous elongated body from a semi-solid state to a solid state.

According to an embodiment of the present invention, the temperature of the second cooling zone is constant temperature or gradient drop.

According to an embodiment of the present invention, the temperature of the second cooling zone decreases gradually with the distance between the second cooling zone and the first cooling zone.

According to an embodiment of the present invention, the temperature of the second cooling zone drops from the first temperature of the first cooling zone to a second temperature, and the second temperature is lower than the first temperature.

According to an embodiment of the present invention, the maximum temperature of the second cooling zone is constantly less than or equal to the minimum temperature of the first cooling zone.

The effect of the present invention is that the hot extrusion molding process includes a secondary cooling step to form the continuous elongated body, and obtain a continuous elongated body with a better degree of solidification and a more stable shape, and at the same time avoid the rapid cooling of the plastic causing incomplete solidification or The problem of cracks.

In order to explain the present invention more clearly, a preferred embodiment is given in conjunction with the drawings in detail as follows.

Please refer to FIG. 1 and FIG. 2, which shows the hot extrusion molding process of the present invention, which at least includes steps S01 to S03.

In step S01, an extrusion molding machine 110 is used to extrude the plastic 101 to form a continuous elongated body 102, wherein the cross-sectional shape of the continuous elongated body 102 is the same as the die hole of the mold 111. For example, if the die hole of the die 111 of the extrusion molding machine 110 is round, the cross section of the continuous elongated body 102 is round; if the die hole of the die 111 of the extrusion molding machine 110 is square, the die hole of the continuous elongated body 102 The cross section is square. In the embodiment of the present invention, the die 111 of the extrusion molding machine 110 has an outlet temperature T1. In the embodiment of the present invention, the continuous elongated body 102 may be, for example, a solid strip or a hollow tube.

In step S02, in the first cooling zone 120, the continuous elongated body 102 is subjected to a first cooling step. The temperature of the first cooling zone 120 is set to a constant temperature or a gradient temperature drop to cool the continuous elongated body 102 from a liquid state to a semi-solid state, so that the plastic 101 is heated in the mold 111 of the extrusion molding machine 110 to a liquid (or molten state) It can be cooled and shaped in the first cooling zone 120. According to an embodiment of the present invention, the temperature of the first cooling zone 120 is set to decrease the temperature gradually with the distance from the mold 111 of the extrusion molding machine 110; for example, the first cooling zone 120 is close to the extrusion molding machine 110 The temperature of the area of the mold 111 is T2, and is close to the exit temperature T1 of the mold 111, and T2 is less than or equal to T1; and the area of the mold 111 of the extrusion molding machine 110 in the first cooling zone 120 has a temperature of T3, and T3 is less than T2. According to an embodiment of the present invention, the first cooling zone 120 is cooled by air; in practice, a fan may be used in the first cooling zone 120 to assist the cooling and shaping of the plastic 101.

In step S03, in the second cooling zone 130, the continuous elongated body 102 is subjected to a second cooling step. The temperature of the second cooling zone 130 is set to a constant temperature or a gradient cooling to cool the continuous elongated body 102 from a semi-solid to a solid state, so that the continuous elongated body 102 cooled to a semi-solid in the first cooling zone 120 can enter the second cooling zone 130 Curing molding. According to an embodiment of the present invention, the temperature of the second cooling zone 130 is set to decrease the temperature gradually with the distance from the first cooling zone 120; for example, in the second cooling zone 130 close to the first cooling zone 120, Its temperature is T4; while in the second cooling zone 130 far from the first cooling zone 120, its temperature is T5, and T5 is less than T4. According to the embodiment of the present invention, the temperature of the second cooling zone 130 is constantly lower than the temperature of the first cooling zone 120. According to the embodiment of the present invention, the maximum temperature of the second cooling zone 130 is always less than or equal to the minimum temperature of the first cooling zone 120. According to an embodiment of the present invention, the first cooling zone 120 and the second cooling zone 130 are respectively located in different cooling devices. According to an embodiment of the present invention, the first cooling zone 120 and the second cooling zone 130 are arranged in the same cooling device. According to an embodiment of the present invention, the second cooling zone 130 uses a cooling liquid to achieve the cooling effect; in practice, the second cooling zone 130 can be a cooling tank with a cooling liquid, and the first cooling zone 120 is cooled to a semi-solid state. The continuous elongated body 102 can be solidified and formed in the second cooling zone 130 by the cooling liquid.

In the embodiment of the present invention, the hot extrusion molding process includes: using a cutting device 140 to cut the continuous elongated body 102, as shown in step S04 in FIGS. 1 and 2. With the cutting device 140, the continuous elongated body 102 is cut into a cut object 103 having a specified length. In the embodiment of the present invention, the cut object 303 can be further processed into various plastic products, such as cutting, polishing and/or combined processes.

In the embodiment of the present invention, the liquid plastic can be cooled and shaped into a semi-solid continuous elongated body in the first cooling zone through the secondary cooling step, and then solidified into a solid continuous elongated body in the second cooling zone to A continuous elongated body with a better curing degree and a relatively stable molded shape is obtained. With the hot extrusion molding process provided by the embodiments of the present invention, the surface of the continuous elongated body and the cut object can be made smoother, and the secondary cooling step can prevent the liquid plastic from being rapidly cooled to the solidification temperature. Incomplete curing or cracks.

On the other hand, the secondary cooling step of the hot extrusion molding process provided by the embodiment of the present invention can set the cooling rate of the plastic according to the fluidity and viscosity of the plastic after liquefaction, so as to avoid the collapse and deformation of the product structure of the traditional hot extrusion molding process. Or problems such as incomplete curing or cracks. Therefore, the hot extrusion molding process provided by the embodiments of the present invention can be widely used in most types of plastics, and is no longer limited by the fluidity or viscosity of the plastic after liquefaction.

For example, Tritan series of copolyesters (which can be obtained from Eastman Chemical Company in the United States) have high fluidity and low viscosity physical properties after heating, and the hot extrusion provided by the embodiment of the present invention The secondary cooling step of the molding process can prevent the product structure of the Tritan series of copolyesters from collapsing, deforming, incomplete solidification, or cracks. Therefore, the hot extrusion molding process provided by the embodiments of the present invention can be widely used in this type of Plastic with high fluidity and low viscosity after heating.

Compared with the general plastic injection molding process or the mold casting process that requires cumbersome manufacturing steps, the hot extrusion molding process provided by the embodiments of the present invention can continuously and quickly produce plastic products, which also provides faster plastic production processes. Convenient method.

The above are only the preferred and feasible embodiments of the present invention. Any equivalent changes made by applying the specification of the present invention and the scope of the patent application should be included in the patent scope of the present invention.

[this invention] 101: Plastic 102: continuous long body 103: Cut 110: Extrusion molding machine 111: Mould 120: The first cooling zone 130: second cooling zone 140: Cutting equipment S01, S02, S03, S04: steps

Figure 1 is a schematic diagram of a hot extrusion manufacturing production line according to an embodiment of the present invention; Figure 2 is a flow chart of a hot extrusion molding process according to an embodiment of the present invention.

101: Plastic

102: continuous long body

103: Cut

110: Extrusion molding machine

111: Mould

120: The first cooling zone

130: second cooling zone

140: Cutting equipment

Claims (10)

A hot extrusion molding process, including: Use an extrusion molding machine to extrude a plastic into a continuous elongated body; Performing a first cooling step on the continuous elongated body in a first cooling zone; and In a second cooling zone, the continuous elongated body is subjected to a second cooling step. The hot extrusion molding process according to claim 1, wherein the first cooling step is to cool the continuous elongated body from a liquid state to a semi-solid state. The hot extrusion molding process according to claim 2, wherein the temperature of the first cooling zone is constant temperature or gradient temperature drop. The hot extrusion molding process according to claim 3, wherein the temperature of the first cooling zone decreases gradually with the distance between the first cooling zone and the extrusion molding machine. The hot extrusion molding process according to claim 4, wherein the temperature of the first cooling zone is reduced from a die outlet temperature of the extrusion molding machine to a first temperature, and the first temperature is lower than the die outlet temperature. The hot extrusion molding process according to claim 1, wherein the second cooling step is to cool the continuous elongated body from a semi-solid state to a solid state. The hot extrusion molding process according to claim 6, wherein the temperature of the second cooling zone is constant temperature or gradient drop. The hot extrusion molding process according to claim 7, wherein the temperature of the second cooling zone decreases gradually with the distance between the second cooling zone and the first cooling zone. The hot extrusion molding process according to claim 8, wherein the temperature of the second cooling zone is reduced from a first temperature of the first cooling zone to a second temperature, and the second temperature is lower than the first temperature. The hot extrusion molding process according to claim 1, wherein the maximum temperature of the second cooling zone is constantly less than or equal to the minimum temperature of the first cooling zone.

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