KR100975019B1 - Process of production for non-glossy polyester bottle - Google Patents

Abstract

In the present invention, 70 to 95% by weight of polyethylene terephthalate chip having an intrinsic viscosity of 0.50 to 1.2 dl / g and a polyethylene chip or polypropylene chip having a melt index of 0.005 to 40 g / 10 minutes are mixed at a ratio of 5 to 30% by weight. The present invention relates to a method for producing a polyester-based matt container, which is injected and blow molded in a molding machine having an uneven portion on a surface of a mold having a specific draw ratio. According to the present invention, it is possible to manufacture a container which can be used as a container for filling high-quality contents such as cosmetics by remarkably reducing the glossiness, which is a characteristic of a container containing PET as a main raw material, without a separate coating process. Due to this, there is provided a method of manufacturing a polyester-based matt container which can improve workability and achieve cost reduction.

Description

Process of production for non-glossy polyester bottle

The present invention relates to a method for producing a polyester container. In general, in the case of a container made of polyethylene terephthalate resin (PET) as a raw material, the PET-specific gloss is expressed on the surface of the molded product after injection molding or injection blow molding. Depending on the application, it may be used as a container to fill high-quality contents such as cosmetics by giving a matting effect to a molded product made of PET as raw materials.To date, a separate matte is applied to the surface of a PET molded container to produce a matting effect. The method of coating the material has been adopted. In such a case, a separate coating process and expensive coating raw materials are required, resulting in poor workability and cost burden.

In addition, in order to give the PET resin the ability of diffuse reflection and absorption of light in the injection molding step or the injection blow molding step, a method of using a mixture of other series, in particular olefin series, has been introduced. There was a situation that the production of matte container is difficult.

Therefore, the present invention is to provide a method of manufacturing a matte container based on PET resin that can solve all the problems of the prior art as described above as a technical problem.

In order to solve the above problems, the present inventors blended PET with polyethylene (PE) or polypropylene (PP), which has a large flow difference with PET, and has a low miscibility, and removes the homogeneity of PET. When designing parison molds whose primary properties are removed and molded prior to the blow process, minimize draw ratios, and form mold surface irregularities in which the surfaces of the blow mold and parison mold are microscopically corroded or sanded. The present invention was completed by knowing that a matte container can be manufactured without a separate coating process.

Therefore, according to the present invention, in the method for producing a polyester container, as a raw material, a polyethylene chip having 70 to 95% by weight of a polyethylene terephthalate chip having an intrinsic viscosity of 0.50 to 1.2 dl / g and a melt index of 0.005 to 40 g / 10 minutes or Provided is a method for manufacturing a polyester-based matt container, which is mixed with a polypropylene chip at a ratio of 5 to 30% by weight and injected and blow molded in a molding machine having an uneven portion on the surface of the mold.

Hereinafter, the present invention will be described in more detail.

PET and olefin resin may be used as the initial raw material in the method of the present invention, it is preferable that polyethylene (hereinafter PE) or polypropylene (hereinafter PP) is used. PE or PP for mixing with the PET can be used that the melt index (hereinafter referred to as MI) is 0.005 ~ 40g / min at 190 ° C conditions of 2.16kg, the smaller the MI, the more the matt effect desired in the present invention Can be further enhanced.

As PET generally used, PET having an intrinsic viscosity of about 0.50 to 1.2 dl / g may be used. Preferably, PET is 0.75 to 0.87 dl / g, and MI of PE (or PP) is preferably 0.005 to 40 g / 10 minutes. When mixing PET and PE (or PP), the ratio of PE (or PP) varies from 1 to 90% by weight, preferably 5 to 30% by weight and more preferably 5 to 10% by weight. If it is less than 5% by weight, it is difficult to realize the matte effect, and when it exceeds 50% by weight, it is difficult to make the injection and blow molding normally because the mixing is not performed well during injection molding.

In the present invention, when PET and PE are mixed, the PET chip and the PE chip may be directly mixed with the set mixing ratio when the parison is injected. In this case, the drying temperature is different from the PET and PE, so that the chip of each polymer is used. It must be dried separately. In addition, in the present invention, it is also possible to manufacture and use a mixed master batch (hereinafter referred to as MC) with two polymers without using the two polymers in a separate chip state, in which case there is an advantage that there is no need to dry separately. . The drying temperature may vary depending on the mixing ratio of PET and PE, and the higher the ratio of PE, the lower the drying temperature. Drying temperature may be determined at 110 ~ 160 ℃.

In addition, in order to increase the matte effect, an inorganic matting agent may be additionally used as an additive. The use amount is 0.01 to 20 parts by weight based on 100 parts by weight of the mixture of PET and PE (or PP). Preferably 1 to 5 parts by weight. The matting agent may be added when preparing the mixed master batch of PET and PE. Preferably, it is desirable to include the quencher as an outer surface layer of the molded article during coin injection.

When PET and PE are mixed in a general injection molding machine, the molded product is molded into a single layer structure. However, in the case of an injection machine capable of making a multi-layered structure by co-injection, only the outer surface layer of the molded product may be composed of blending of PET and PE, or may be molded by MC described above. In the present invention, one of the two types of the polymer may be selected from the two stages of the injection molding machine and the reheat blow molding machine and the one stage of the injection blow molding machine. In the case of a two-stage molding machine, mass production is possible, and the degree of gloss can be controlled by adjusting the conditions in the reheat blow molding machine. First-stage injection blow molding machine is preferable for small quantity production, and there is an advantage that it is easy to control the production quantity.

The PET matte molded article of the present invention is required to form micro irregularities on the mold surface by treating the mold surface by corrosion or sanding. In the case of injection blow molding which simultaneously performs injection and blow processes, the surface of the blow mold and the parison mold need to be corroded or sanded, and the design draw ratio between the two molds needs to be adjusted. Adjusting the draw ratio has a draw ratio in which the axial length of the blow molded product is 1 to 3 times the axial length of the parison obtained by the injection process, and draws 1 to 4 times the draw ratio at the maximum diameter in the radiation direction (the transverse direction). It is desirable to have. The thickness of the blow molded product is 0.025 to 0.9 times the parison thickness. More preferred designs have an elongation ratio of 1.2 to 1.5 times in the axial direction and 1.3 to 1.7 times in the maximum diameter in the transverse direction and a thickness of 0.3 to 0.7 times. Such a design can maintain strength while achieving minimum draw ratio.

The micro uneven surface of the mold may generally be implemented by using a solvent to corrode, or by sanding, and may also use other methods of giving unevenness. It is important, however, that the molded product is free from mold and release problems. The roughness of the mold irregularities is represented by height, and the roughness of the irregularities is adjusted to 0.01 to 500 µm, more preferably 1 to 10 µm. If the roughness is less than 0.01㎛ the effect of diffuse reflection is reduced, if more than 500㎛ roughness is severe and also the effect of diffuse reflection is reduced.

Particularly, in the two-step molding machine consisting of a two-step injection molding machine and a reheat blow molding machine, the parison mold is subjected to the molding. When the mold is opened and closed, the parison may be broken, and thus, care should be taken. Injection molding machines and blow molding machines can be used as long as they are commonly used commercial injection molding machines and blow or stretch blow molding machines. However, when the injection machine size is small and the L / D of the screw is 20: 1 or less, it is necessary to replace the screw to a well-mixed type, or to optimize the process conditions to use MC or to uniform blending.

In the following examples, non-limiting examples of producing the polyester-based matt container of the present invention.

Example 1

PET chips with an inherent viscosity of 0.80 dl / g and HDPE chips with a MI of 0.10 g / 10 min were used as raw materials. PET was dried for 5 hours at 160 ° C. in a dehumidifying dryer before injection, and HDPE was dried at 80 ° C. for 10 hours in a vacuum dryer. Immediately before injection, the PET: HDPE was mixed in a 9: 1 ratio in a rotary stirrer and introduced into the injection machine hopper. The molding machine manufactured a 200 ml cylindrical container by using a Nissei Injection Blow Machine which is blow molded simultaneously with injection stretching. The parison is designed to have a mass of 45 g when using the whole amount of PET, and the cylindrical container manufactured is designed to have an elongation ratio of 1.2 times on the axis and 1.5 times on the side with respect to the parison. The barrel temperature of the injection molding machine was set at 255 ° C, and injection and cooling were performed for 11 seconds each.

[Example 2]

Using the same injection molding machine as in Example 1 to prepare a 200ml cylindrical container of the same capacity, the PET used was an inherent viscosity of 0.80dl / g, and MIPE 0.010g / min HDPE was used. Drying in the same manner, PET: PE was blended at a 7: 3 ratio in a rotary stirrer immediately before injection, and then injected into the injection machine hopper. The barrel temperature of the injection molding machine was set at 255 ° C, and injection and cooling were performed for 11 seconds each.

Example 3

Using the same injection molding machine as in Example 1 to prepare a 200ml cylindrical container of the same capacity, PET with an intrinsic viscosity of 0.80dl / g, HDPE with a 0.010g / min MI was used. And while mixing PET and HDPE, 5 parts by weight of silica-based matting agent was extruded in an extruder while mixing to prepare a palletized MC. PET was dried for 5 hours at 160 ° C. in a dehumidifying dryer before injection, and PE and MC were dried at 80 ° C. for 10 hours in a vacuum dryer. Then, PET: PE: MC was blended in a ratio of 7: 2: 1 in a rotary stirrer immediately before injection, and then injected into the injection machine hopper. The barrel temperature of the injection machine was set to 255 ° C and the cycle time was 25 seconds.

Example 4

Using the same injection molding machine as in Example 1 to prepare a 200ml cylindrical container of the same capacity, the PET used was an intrinsic viscosity of 0.80 dl / g, HDPE used a polymer having a MI of 0.10g / 10 minutes. And 5 parts by weight of silica-based matting agent was added while mixing PET and HDPE at 5: 5 to extrude in an extruder to prepare a pelletized MC. In the MC manufacturing method, PET was dried for 5 hours at 160 ° C. in a dehumidifying dryer before injection, and PE was dried at 80 ° C. for 10 hours in a vacuum dryer. PET and PE were mixed in a ratio of 7: 3 PET: PE in a rotary stirrer immediately before injection into the injection machine hopper. At this time, the drying method before the injection into the injection machine hopper was the same as in Example 3. The barrel temperature of the injection machine was set at 255 ° C and the cycle time was 25 seconds.

Comparative Example 1

A 500 ml cylindrical container of the same capacity was molded using 100% of a PET resin as a raw material using the same molding machine used in Example 1. PET was dried using a PIOVAN dehumidifying dryer and dried for 5 hours using heated air at a drying temperature of 160 ° C. and a dew point of −50 ° C. The barrel temperature of the injection machine was set at 260 ° C and the cycle time was 25 seconds. The glossiness was measured under the condition that the incident light was 20 ° and 60 ° using a gloss meter, and it is shown in Table 1 in comparison with the glossiness of the containers according to Examples 1-3.

No. Incident light 20 °  Incident light 60 ° Example 1 8.6 17.5 Example 2 5.6 15.7 Example 3 4.2 12.3 Example 4 3.9 12.5 Comparative Example 1 183.1 167.2

The products molded by the method of Examples 1 to 4 had a translucent white tone, the surface was reduced gloss than the product of Comparative Example 1 molded from PET100% and the glossiness shown in Table 1 was also more noticeable than Comparative Example 1. You can see that it comes out low.

As described above, according to the present invention, it is possible to manufacture a container which can be used as a container for filling high-quality contents, such as cosmetics, by significantly reducing the glossiness, which is a characteristic of a container containing PET as a main raw material, without a separate coating process. Due to the exclusion of the coating process has the advantage of improving workability and cost reduction.

Claims (5)

In the method for producing a polyester container, 5 to 95% by weight of polyethylene terephthalate chip having an intrinsic viscosity of 0.50 to 1.2 dl / g and a polyethylene chip or polypropylene chip having a melt index of 0.005 to 40 g / 10 minutes are used. A method of manufacturing a polyester-based matt container, characterized in that the injection and blow molding are carried out in a molding machine having a mixture mixed at a ratio of ˜30% by weight, and the roughness of the mold is 0.01 to 500 μm. . delete The method for producing a polyester-based matt container according to claim 1, further comprising 0.01 to 20 parts by weight of an inorganic matting agent with respect to 100 parts by weight of the mixture. The axial length of the container during blow molding has a draw ratio of 1 to 3 times the axial length of the parison obtained in the injection molding machine, and a draw ratio of 1 to 4 times the maximum diameter in the transverse direction. Method for producing a polyester-based matt container, characterized in that made. The method for producing a polyester-based matt container according to any one of claims 1, 3, and 4, wherein all or part of the raw materials to be injected into the molding machine are manufactured by using a master batch chip and supplied to the molding machine. .