TW202146207A - Crystalline plastic molding method no need to use an expensive cooling system and build an additional crystallization apparatus - Google Patents

Abstract

The invention relates to a crystalline plastic molding method, which includes providing a raw material; performing a heating molding; performing a cooling crystallization; performing a cooling demolding step to form a crystalline plastic finished product. In this way, using a stepwise cooling technology can achieve the effects of cooling crystallization and cooling demolding in a mold concurrently, so that not only an expensive cooling system is not required, but also an additional crystallization apparatus does not need to build. At the same time, it can improve the process yield, thereby reducing the cost of equipment and manpower, and greatly reducing the total process time.

Description

Forming method of crystalline plastic

The present invention belongs to a molding technology of crystalline plastics, and specifically refers to a molding method of crystalline plastics that can be molded in one time, so as to reduce the cost of molding equipment and labor, and at the same time, the speed of molding can be accelerated, and the Further improve the yield of its molding.

Press, crystalline materials such as containers made of polyethylene [PE], polypropylene [PP], polyethylene terephthalate [PET], polyphenylene sulfide [PS], etc., of which PET has excellent Gas barrier properties; pressure resistance, creep resistance; impact resistance; transparency, surface gloss; odorless and aroma retention; On food containers, such as the so-called treasure bottle.

PET is a high molecular polymer, and its most important characteristic is its molecular weight. The molecular weight is the average number of molecules in the PET molecular chain. The longer the number of molecular chain connections, the better the physical properties of PET. And PET is a crystalline resin with a specific gravity of about 1.4, a melting point of 245°C, and a molding temperature of about 290°C to 315°C. Therefore, when it is molded in the mold, as shown in the first figure, first, the initial embryo is formed. Next, heat blow molding is performed, which is to heat the initial embryo to a molding temperature (such as 290°C to 315°C), and then use the blow molding technique to expand the initial embryo into a predetermined size body in the mold. After that, cooling and demoulding is performed, which uses the ice-water system set in the mold to cool the mold to normal temperature (such as 20°C to 30°C), so as to facilitate demolding of the molded body after molding. Immediately afterwards, the temperature-raising crystallization is carried out, and in order to improve the strength of the molded body, the molded body that has been demolded and cooled to room temperature is placed in a crystallizer, and then heated to the crystallization temperature [such as 150 ° C ~ 170 ° C], so that The uncrystallized molded body is crystallized and shaped, and finally, cooling molding is performed, and after completing the crystallization of the molded body, the molded body is cooled to normal temperature again to form a complete carrier.

In the conventional crystalline plastic molding method, the mold needs to be cooled by an ice-water system so that the mold can be quickly lowered to normal temperature for demoulding, and a crystallizer needs to be used to heat up for crystallization. However, due to the high difficulty in designing the mold of the ice-water system and the high cost of construction, in addition, an additional crystallizer needs to be built, which not only occupies the site space, but also greatly increases the overall equipment cost. Increasing the process time may even result in defective products, causing the surface of the finished product to become whitened and destroying the aesthetics of the product.

In other words, since the existing crystalline plastics are subjected to repeated heating and cooling and demolding during the process, problems such as "high equipment and labor costs", "long process time" and "high defect rate" arise. Solving the aforementioned problems in injection and crystallization is expected by the industry, and is also a technical problem to be solved by the present invention.

The reason is that the inventors of the present invention have made in-depth discussions on the problems faced by the existing crystalline plastics, and have finally successfully developed a method for forming crystalline plastics through continuous efforts in improvement and trial production based on the needs of technological development in recent years. Overcome the existing shortcomings and inconveniences of high equipment and labor costs and long process time caused by heating and cooling.

Therefore, the main purpose of the present invention is to provide a molding method of crystalline plastic, so as to simplify the process procedure, effectively shorten the overall process time, and improve the molding yield.

In addition, another main purpose of the present invention is to provide a method for forming crystalline plastic, which can reduce the cost of equipment installation and further save equipment space and manpower.

Based on this, this creation mainly realizes the aforementioned purpose and effect through the following technical means: It includes:

First, carry out a provision of raw materials;

Next, heat forming: after being heated to the forming temperature, the raw material is formed into a product in the mold;

Then, cooling and crystallization: after molding, cooling the mold to a crystallization temperature to crystallize and shape the uncrystallized product; and

Finally, carry out cooling and demoulding: after the cooling and crystallization of the product is completed, the mold is further cooled to normal temperature to facilitate demoulding after molding.

Thereby, through the specific realization of the above technical means, the molding method of the crystalline plastic of the present invention utilizes the technology of staged cooling to achieve the effects of cooling crystallization and cooling and demoulding, so not only does not need an expensive ice-water system, but also In addition, the establishment of a crystallizer can improve the process yield, thereby reducing the cost of equipment and labor required, and can greatly reduce the process time, so as to increase its added value and further improve its economic benefits.

And the present invention utilizes the following technical means to further achieve the aforementioned purposes and effects; such as:

The raw material can be a PET bottle preform, the heating temperature is 290°C to 315°C, and the crystallization temperature is 120°C to 220°C, and the crystallization temperature lasts for 1 to 10 minutes.

In order to enable your examiners to further understand the structure, characteristics and other purposes of the present invention, the following are preferred embodiments of the present invention, which are described in detail with the accompanying drawings, so that those who are familiar with the technical field can implement them in detail.

The present invention is a molding method of crystalline plastic, and the accompanying drawings illustrate specific embodiments of the present invention and its components, all references to front and back, left and right, top and bottom, top and bottom, and horizontal and vertical , is only used for the convenience of description, and does not limit the present invention, nor does it limit its components to any position or spatial direction. The dimensions specified in the drawings and the description may be changed according to the design and requirements of the specific embodiment of the present invention without departing from the scope of the patent application of the present invention.

The molding method of the crystalline plastic of the present invention, as disclosed in the second figure, includes the steps of: providing a raw material; performing a heating molding; performing a cooling crystallization; And form a crystalline plastic product;

And the detailed description of the molding method of the present invention is still shown in the second figure, and takes PET bottle blowing as the main embodiment;

First, carry out a supply of raw materials: such as pre-forming a preform;

Next, heat forming: after heating the preform to the forming temperature (such as 290°C to 315°C), the preform is expanded into a predetermined size bottle body in the mold by the blowing technique;

After that, carry out cooling crystallization: after the preform is blow-molded into a bottle body, use the temperature controller that exists in the mold to cool down to a crystallization temperature (such as 120 ° C ~ 220 ° C), and keep it at the crystallization temperature for 1 minute to 10 minutes to crystallize and shape the uncrystallized bottle; and

Finally, carry out cooling and demoulding: after the cooling and crystallization of the bottle body is completed, the mold is further cooled to normal temperature (such as 20 ° C ~ 30 ° C), so as to facilitate the demoulding of the molded bottle body and form a complete bottle body.

It can be seen from the above description that the method for forming crystalline plastics of the present invention utilizes the step-by-step cooling technology to achieve the effects of cooling crystallization and cooling and demoulding, so not only does not require an expensive ice-water system, but also does not need to build an additional crystallizer , effectively reduce equipment costs, simplify the process, save manpower and process time, and improve process yield, which can greatly increase performance, efficiency, and product quality, and effectively save site space, and effectively improve raw materials, The turnover rate of finished products and funds can greatly improve the profit and competitiveness, and it can indeed meet the economic benefits of industrial utilization.

To sum up, it can be understood that the present invention is an invention with excellent creativity, in addition to effectively solving the problems faced by habitual practitioners, it also greatly improves the efficacy, and there is no identical or similar product creation or product creation in the same technical field. It can be used publicly, and at the same time, it has the enhancement of efficacy, so the present invention has met the requirements of "novelty" and "progressiveness" of the invention patent, and an application for an invention patent is filed in accordance with the law.

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Figure 1: A schematic diagram of a conventional crystalline plastic molding process.

The second figure: a schematic diagram of the flow structure of the molding method of the crystalline plastic of the present invention.

Claims (2)

A method for forming crystalline plastic, comprising: First, carry out a provision of raw materials; Next, heat forming: after heating to the forming temperature, the raw material is formed into a product in a mold; Then, conduct cooling and crystallization: after molding, the mold is cooled to a crystallization temperature to crystallize and shape the product that has not yet been crystallized; and Finally, cooling and demoulding is performed: after the cooling and crystallization of the product is completed, the mold is further cooled to normal temperature to facilitate demoulding after molding. The method for forming a crystalline plastic according to claim 1 of the scope of the application, wherein the raw material can be a PET bottle preform, the heating forming temperature is 290°C-315°C, and the crystallization temperature is 120°C-220°C, and the The crystallization temperature lasts from 1 minute to 10 minutes.

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