TWI737327B - Molding method of crystalline plastic - Google Patents

Abstract

The present 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 demoulding step to form a crystalline plastic finished product, thereby using a stepwise cooling Technology, and can achieve the effect of cooling crystallization and cooling demolding in a mold at the same time, so that not only does not need an expensive cooling system, but also does not need to build an additional crystallization machine, and at the same time can improve the process yield, thereby reducing the cost The cost of equipment and manpower required can greatly reduce the total process time.

Description

Molding 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 a mold at a time, so as to reduce the cost of molding equipment and labor, and at the same time, the molding speed can be increased. Further improve its molding yield.

According to, crystalline materials such as containers made of polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PS), etc., among which PET has excellent Gas barrier properties; pressure resistance, creep resistance; impact resistance; transparency, surface gloss; odorless and fragrance retention; and it meets the safety of food hygiene, beautiful and easy to shape, and is widely used On food containers, such as PET bottles.

PET is a high molecular polymer. The most important characteristic is its molecular weight. The molecular weight is the uniform 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 between 290°C and 315°C. Therefore, when it is molded in the mold, as shown in the first figure, first, the primary embryo is formed. Then, heat blow molding is performed, which is to heat the primary embryo to a molding temperature (such as 290°C to 315°C), and then use the blow molding technology to expand the primary embryo into a predetermined size shape in the mold. After that, cooling and demolding is performed, which uses the ice water system set in the mold to cool the mold to room temperature (such as 20°C to 30°C) to facilitate the demolding of the molded body after molding. Immediately afterwards, temperature rise crystallization is carried out, and in order to improve the strength of the molded body, the molded body cooled to room temperature after demolding is placed in a crystallizer, and the temperature is raised again to the crystallization temperature (such as 150°C to 170°C), so that The shaped body that has not yet been crystallized is crystallized and shaped, and finally, the temperature is lowered and shaped, and after the crystal phase of the shaped body is completed, the temperature of the shaped body is cooled to room temperature again to form a complete carrier.

In the conventional crystalline plastic molding method, the mold needs to use an ice-water system to cool down, so that it can quickly drop to room temperature for demoulding, and an additional crystallizer needs to be used to raise the temperature for crystal shaping. However, because the mold design of the ice water system is difficult and the construction cost is high, and another crystallizer needs to be built. This not only takes up space, but also greatly increases the overall equipment cost. In addition, the temperature rises and falls continuously. Increasing the process time may even form defective products, causing the surface of the finished product to form a whitening phenomenon and destroy the appearance of the product.

In other words, because the existing crystalline plastics are being molded, due to the effects of repeated temperature rises and falls and demolding during the process, problems such as "high equipment and labor costs", "long process time", and "high defect rate" arise, so how Solving the aforementioned problems faced by injection and crystallization is what the industry expects, and it is also a technical problem to be solved by the present invention.

The reason is that the inventors have made an in-depth discussion on the problems faced by the existing crystalline plastics. Based on the needs of technological development in recent years, through continuous efforts of improvement and trial production, they finally successfully developed a method for molding crystalline plastics. Overcome the existing shortcomings and inconveniences of high equipment and labor costs and long process time caused by temperature rise and fall.

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

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

Based on this, this creation is mainly through the following technical means to achieve the aforementioned goals and effects: It includes:

First, proceed to provide raw materials;

Then, heat molding is performed: after heating to the molding temperature, the raw material is molded into a product in the mold;

After that, cooling and crystallization: after forming, cooling the mold to a crystallization temperature to crystallize and shape the product that has not yet been crystallized; and

Finally, perform cooling and demolding: After the cooling and crystallization of the product is completed, the mold is further cooled to room temperature to facilitate demolding after molding.

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

In addition, the present invention uses the following technical means to further achieve the aforementioned objectives and effects; such as:

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

In order to enable your reviewer to further understand the composition, features and other purposes of the present invention, the following is a preferred embodiment of the present invention, which is described in detail with the drawings, and at the same time allows those familiar with the technical field to be able to implement it in detail.

The present invention is a method for molding crystalline plastic. The attached drawings illustrate the 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 drawings and the size specified in the specification can 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 is as disclosed in the second figure, which includes the steps of providing raw materials; performing heating molding; performing cooling crystallization; performing cooling demoulding. To form a crystalline plastic product;

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

First, perform a supply of raw materials: for example, a preform is formed in advance;

Next, heat molding: After heating the preform to the molding temperature (for example, 290°C to 315°C), the bottle blowing technique is used to expand the preform into a bottle of a predetermined size in the mold;

Then, perform cooling and crystallization: After the preform is blow-molded into the bottle body, use the temperature controller that exists in the mold to cool to a crystallization temperature (such as 120°C to 220°C), and keep it at the crystallization temperature for 1 minute to 10 minutes to crystallize and shape the bottle that has not yet crystallized; and

Finally, perform cooling and demolding: After cooling and crystallization of the bottle body, the mold is further cooled to normal temperature (such as 20°C to 30°C) to facilitate the demolding of the molded bottle body to form a complete bottle body.

From the foregoing description, it can be seen that the molding method of the crystalline plastic of the present invention utilizes the step-by-step cooling technology to achieve the effects of cooling crystallization and cooling demoulding, so that not only does not need an expensive ice water system, but also does not need to build a crystallizer. , Which can effectively reduce equipment costs, while simplifying the process, saving manpower and process time, and improving the process yield, which can greatly increase efficiency, efficiency and product quality, and effectively save the use of site space, and effectively improve raw materials, The turnover rate of finished products and funds has greatly increased profitability and competitiveness, which can indeed meet the economic benefits of industrial use.

In summary, it can be understood that the present invention is an extremely creative invention. In addition to effectively solving the problems faced by habitants, it also greatly enhances its efficacy. In addition, there is no similar or similar product creation or creation in the same technical field. It is publicly used and has enhanced efficacy. Therefore, the present invention has met the requirements of "novelty" and "progressiveness" of invention patents, and an application for invention patents has been filed in accordance with the law.

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Figure 1: Schematic diagram of the conventional crystalline plastic molding process.

Figure 2: A schematic diagram of the flow structure of the crystalline plastic molding method of the present invention.

Claims (2)

A molding method of crystalline plastic, which comprises: First, proceed to provide raw materials; Then, heat forming is performed: after heating to the forming temperature, the raw material is formed into a product in a mold; Then, perform cooling crystallization: after forming, the mold is cooled to a crystallization temperature to crystallize and shape the product that has not yet been crystallized; and Finally, perform cooling and demolding: After the cooling and crystallization of the product is completed, the mold is further cooled to room temperature to facilitate demolding after molding. For the crystalline plastic molding method described in claim 1, wherein the raw material can be a PET preform, the heating molding temperature is 290℃～315℃, and the crystallization temperature is 120℃～220℃, and the The crystallization temperature lasts from 1 minute to 10 minutes.

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