KR20230158162A - Manufacturing method of eco-friendly container with excellent chemical resistance - Google Patents

Abstract

The present invention relates to a method of manufacturing an eco-friendly container with excellent chemical resistance, and more specifically, to a raw material mixing step of mixing high-density polyethylene, eco-friendly filler and colorant, and injecting the mixture prepared through the raw material mixing step into an injection blow molding machine. A melting step, an injection step of injecting the molten mixture through the melting step, a blow molding step of blow molding the mixture injected through the injection step, and a cooling step of cooling the molded product manufactured through the blow molding step. It comes true.
Containers manufactured through the above process not only have excellent mechanical properties, chemical resistance, and appearance quality, but also have an environmentally friendly effect because calcium carbonate made from eggshell is used.

Description

Method for manufacturing eco-friendly containers with excellent chemical resistance {MANUFACTURING METHOD OF ECO-FRIENDLY CONTAINER WITH EXCELLENT CHEMICAL RESISTANCE}

The present invention relates to a method of manufacturing an eco-friendly container with excellent chemical resistance, and more specifically, to provide an eco-friendly container that not only has excellent mechanical properties, chemical resistance, and appearance quality, but also uses calcium carbonate made from eggshells. This relates to a method of manufacturing eco-friendly containers with excellent chemical resistance.

Polyethylene containers with excellent chemical resistance are mainly used to contain chemicals or drugs. Their contents include solvents and cleaning agents such as hydrofluoric acid, sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, hydrogen peroxide, aqueous ammonia, and phenol. These include non-hazardous chemicals such as high-purity chemicals, antifreeze, emulsifiers, glycerol, glycerin, latex, polyvinyl alcohol, and dyes, as well as chemicals used in daily life such as fruit juice, soy sauce, vinegar, and neutral detergents.

Containers containing these chemicals require chemical resistance that allows them to be stored for a long period of time without changing the composition, and also require excellent drop resistance, which is a basic physical property of the container, which can prevent damage when handling containers containing high-purity chemicals. This is because of the risk it may pose to the human body and the fact that it is not easy to pollute the surrounding environment or remove it. Accordingly, efforts have been made to increase melt tension and weight average molecular weight to increase drop impact resistance.

Korean Patent Publication No. 10-2002-0049130 describes a polyethylene-based resin composition used as a material for hollow molds containing high-purity chemicals, and has a high load (216 kg, 190°C) melt flow index (ASTM D1238 standard) of less than 20 g/10 minutes. It consists of 65 to 95% by weight of polyethylene resin produced by a catalyst or chromium catalyst and 35 to 5% by weight of polyethylene resin produced by a metarosene catalyst with a high load melt flow index in the range of 2 to 50 g/10 minutes. A polyethylene-based resin composition using a heterogeneous catalyst is described,

Korean Patent Publication No. 10-2003-0066409 describes a technology to increase impact strength by manufacturing high-density polyethylene with increased density and average molecular weight. The resin has MFR measured with a load of 216 kg and MFR measured with a load of 216 kg. The ratio (MFR216kg/MFR 216kg) was set to be less than 200.

However, although the above technologies have the advantage of improving impact strength, they do not improve the glossiness of the surface of the container, and they do not improve dynamic stiffness other than drop impact strength, so there is a problem that the appearance of the container is poor.

Korean Patent Publication No. 10-2002-0049130 (June 26, 2002) Korean Patent Registration No. 10-0525702 (2005.10.26.)

The purpose of the present invention is to provide a method for manufacturing an eco-friendly container that not only has excellent mechanical properties, chemical resistance, and appearance quality, but also has excellent chemical resistance by using calcium carbonate made from eggshells to manufacture an eco-friendly container.

The purpose of the present invention is to include a raw material mixing step of mixing high-density polyethylene, eco-friendly filler and colorant, a melting step of feeding the mixture prepared through the raw material mixing step into an injection blow molding machine and melting it, and injection of the melted mixture through the melting step. It consists of an injection step, a blow molding step of blow molding the mixture injected through the injection step, and a cooling step of cooling the molded product manufactured through the blow molding step, and the eco-friendly filler is calcium carbonate made from eggshell. This is achieved by providing a method of manufacturing an eco-friendly container characterized by excellent chemical resistance.

According to a preferred feature of the present invention, the raw material mixing step is comprised of 100 parts by weight of high-density polyethylene, 40 to 60 parts by weight of eco-friendly filler, and 5 to 15 parts by weight of colorant.

According to a more preferred feature of the present invention, in the raw material mixing step, an antioxidant of 0.05 to 0.2 parts by weight is further contained relative to 100 parts by weight of the high-density polyethylene, and the antioxidant is octadecyl-3-(3,5-di-tert- At least one selected from the group consisting of butyl-4-hydroxyphenyl)propionate and tris(2,4-di-tert-butylphenyl)phosphite and oxidized bis(hydrogenated tallowalkyl)amine. It is said to be done.

According to a more preferred feature of the present invention, in the raw material mixing step, 0.5 to 3 parts by weight of Teflon-based resin is added compared to 100 parts by weight of the high-density polyethylene.

According to an even more preferred feature of the present invention, the Teflon-based resin is made of at least one selected from the group consisting of polytetrafluoroethylene, ethylenetetrafluoroethylene copolymer, and fluorinated ethylenepropylene copolymer.

According to an even more preferred feature of the present invention, the eco-friendly filler is used by drying at a temperature of 70 to 80° C. for 40 to 60 minutes.

According to an even more preferred feature of the present invention, the injection step is performed by injecting the mixture melted through the melting step into the injection mold for 6 to 8 seconds at a pressure of 300 to 400 Psi.

The method of manufacturing an eco-friendly container with excellent chemical resistance according to the present invention not only has excellent mechanical properties, chemical resistance, and appearance quality, but also shows an excellent effect of providing an eco-friendly container by using calcium carbonate made from eggshell.

Figure 1 is a flowchart showing a method of manufacturing an eco-friendly container with excellent chemical resistance according to the present invention.

Below, preferred embodiments of the present invention and the physical properties of each component are described in detail, but are intended to be described in detail so that those skilled in the art can easily practice the invention. This does not mean that the technical idea and scope of the present invention are limited.

The method of manufacturing an eco-friendly container with excellent chemical resistance according to the present invention includes a raw material mixing step (S101) of mixing high-density polyethylene, eco-friendly fillers, and colorants, and the mixture prepared through the raw material mixing step (S101) is input into an injection blow molding machine. A melting step (S103) of melting, an injection step (S105) of injecting the mixture melted through the melting step (S103), a blow molding step (S107) of blow molding the mixture injected through the injection step (S105), and It consists of a cooling step (S109) of cooling the molded product manufactured through the blow molding step (S107).

The raw material mixing step (S101) is a step of mixing high-density polyethylene, eco-friendly filler, and colorant, and is preferably comprised of 100 parts by weight of high-density polyethylene, 40 to 60 parts by weight of eco-friendly filler, and 5 to 15 parts by weight of colorant.

The high-density polyethylene has a high-load melt flow index of 50 g/10 minutes or less, a weight average molecular weight of 250,000 to 450,000, a molecular weight distribution of 12 to 25, MI216/MI216 of 50 to 200, and a density of 0.950 g/cm3 or more. It is desirable to use

In addition, the high-density polyethylene is preferably an ethylene homopolymer or a copolymer of ethylene and one or more monomers, and the monomers include linear or branched alpha olefins containing 4 to 6 carbon atoms, for example, Butene-1, hexene-1, and 4-methylpentene-1 can be used.

If the high load melt flow index exceeds 50 g/10 min, it is undesirable because the melt tension decreases, the thickness uniformity of the molded product deteriorates, or molding defects in the bottle occur, and the weight average molecular weight If it is less than 250,000, it is undesirable because the impact resistance of the container is weakened. If it exceeds 450,000, it is undesirable because it reduces processability and causes appearance defects. If the molecular weight distribution is less than 12, it is difficult to obtain the target molecular weight distribution of the final resin composition, resulting in lower fluidity. This is undesirable because the appearance is not satisfactory, and if it exceeds 25, the amount of low molecular weight components increases, causing sagging of the parison and deterioration of container loadability, which is undesirable. In addition, if the MI216/MI216 is less than 50, the fluidity of the resin deteriorates during processing, which is undesirable because the resin generates heat and is prone to causing melt fractures, and if it exceeds 200, the mechanical properties of the molded product deteriorate and do not have appropriate container properties. This is undesirable, and if the density is less than 0.950 g/cm3, the strength of the hollow molded container decreases, which is undesirable.

The eco-friendly filler contains 40 to 60 parts by weight and serves to improve the mechanical properties of the eco-friendly container with excellent chemical resistance manufactured through the present invention. In this case, the eco-friendly filler uses calcium carbonate made from eggshell. It is desirable.

Calcium carbonate made from eggshells used as the above-mentioned eco-friendly filler is environmentally friendly because it is manufactured through a process of collecting discarded eggshells, flame-treating them, and then pulverizing them.

In addition, the eco-friendly filler is preferably used by drying at a temperature of 70 to 80°C for 40 to 60 minutes. Since the moisture content of the filler dried at the above temperature and time is significantly reduced, the process of forming the container However, it is possible to suppress the phenomenon of physical properties being deteriorated due to moisture after molding.

If the drying temperature of the eco-friendly filler is less than 70℃ or the drying temperature is less than 40 minutes, moisture cannot be removed efficiently, and if the drying temperature of the eco-friendly filler exceeds 80℃ or the drying time exceeds 60 minutes, energy efficiency From this point of view, it is not desirable.

If the content of the eco-friendly filler is less than 40 parts by weight, the above effect is minimal, and if the content of the eco-friendly filler exceeds 60 parts by weight, the above effect is not significantly improved, but the mechanical strength of the container is lowered and the external quality is deteriorated. It is undesirable because it becomes defective.

The colorant contains 5 to 15 parts by weight, and is preferably applied in the form of a masterbatch made by mixing 10 to 20 parts by weight of pigment with 100 parts by weight of high-density polyethylene. The pigment includes titanium oxide and oxidation, which are pigments that impart white color. It is preferably made of at least one selected from the group consisting of zinc, lithopone and lead white.

If the content of the colorant is less than 5 parts by weight, a uniform color cannot be imparted to the entire container, and if the content of the colorant exceeds 15 parts by weight, the content of high-density polyethylene or filler is relatively reduced, which is undesirable.

In addition, in the raw material mixing step (S101), an additional 0.05 to 0.2 parts by weight of antioxidant may be added compared to 100 parts by weight of high-density polyethylene. When the antioxidant is contained as described above, not only the antioxidant effect of the manufactured container but also the chemical resistance is improved. It can be improved further.

At this time, the antioxidants include octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris(2,4-di-tert-butylphenyl)phosphite, and oxidase. Ized bis(hydrogenated tallowalkyl)amine is preferably composed of at least one selected from the group consisting of amines.

If the content of the antioxidant is less than 0.05 parts by weight, the effect is minimal, and if the content of the antioxidant exceeds 0.2 parts by weight, the mechanical properties of the manufactured container may be reduced.

In addition, in the raw material mixing step (S101), 0.5 to 3 parts by weight of Teflon-based resin may be added compared to 100 parts by weight of high-density polyethylene. When Teflon-based resin is contained, the surface gloss of the container can be further improved, and the molding process It plays a role in reducing shock skin on the surface while maintaining appropriate melt tension by appropriately controlling the viscosity of the raw materials.

At this time, the Teflon-based resin is a group consisting of polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene copolymer (ETFE), and fluorinated ethylene propylene copolymer (FEP). It is preferable that it consists of one or more selected from.

If the content of the Teflon-based resin is less than 0.5 parts by weight, the above effect is minimal, and if the content of the Teflon-based resin exceeds 3 parts by weight, the viscosity of the raw material increases excessively, which may reduce moldability.

The melting step (S103) is a step of putting the mixture prepared through the raw material mixing step (S101) into an injection blow molding machine and melting it. The mixture prepared through the raw material mixing step (S101) is equipped with five heater bands. It is melted by passing it through a screw, and the heater band is set at 190 to 195°C for the first, 210 to 220°C for the second, 220 to 230°C for the third, 210 to 220°C for the fourth, and 230 to 250°C for the fifth. It is desirable to proceed with melting by setting it.

Additionally, in order to prevent damage to the heater band, it is desirable to install coolant circulation covers on the outside of the top and bottom of the screw to prevent the outside temperature from becoming high.

The injection step (S105) is a step of injecting the mixture melted through the melting step (S103), and is performed by injecting the mixture melted through the melting step (S103) into an injection mold. The mixture is injected into the injection mold. It is desirable to allow a waiting time of 0.5 to 0.8 seconds before the injection time so that the injection mold has the force to completely close before the injection mold is closed. At this time, at least 0.2 seconds, which is the minimum time for the injection mold to be closed, must be secured. do.

In addition, a time of 6 to 8 seconds and a pressure of 300 psi to 400 psi are applied to ensure that the mixture is completely injected into the injection mold, and after the mixture is completely injected into the injection mold, the injection nozzle can be retracted by pressure to prevent the mixture from overflowing into the injection mold. It is desirable to design it so that

In addition, cooling is performed for 1.5 to 2.5 seconds with the injection mold closed so that the mixture placed in the injection mold can maintain its shape without flowing down due to high temperature. At this time, it is desirable to design the injection mold to allow cooling water to circulate so that the mixture can be cooled while the injection mold is closed. The temperature for circulation cooling of the injection mold is 30 to 85°C at the container inlet and 90 to 100°C at the body. and the bottom portion is preferably set to 85 to 95°C.

In the injection step (S105), if the mixture input pressure is less than 300 psi or the injection time is less than 6 seconds, the mixture cannot be completely injected into the injection mold. If the mixture input pressure exceeds 400 psi or the injection time exceeds 8 seconds, the mixture cannot be completely injected into the injection mold. If this happens, the injection amount of the mixture in the injection mold increases excessively, thereby excessively increasing the thickness of the container, and the blow molding performed in the blow molding step (S107) does not proceed properly.

The blow molding step (S107) is a step of blow molding the mixture injected through the injection step (S105). After the mixture injected into the injection mold through the injection step (S105) is cooled, the cooled mixture is After transferring to the blow mold, the blow mold is closed. At this time, it is desirable to wait 0.5 to 0.8 seconds before proceeding with the blow molding process, as with the injection mold, so that the blow mold can be fully closed.

After the injection mold is completely closed, it is desirable to proceed with blow molding by supplying air to the blow mold for 7 to 10 seconds.

The cooling step (S109) is a step of cooling the molded product manufactured through the blow molding step (S107), and consists of cooling the molded product manufactured through the blow molding step (S107) to a temperature of 1 to 20 ° C. .

At this time, in the cooling step (S109), in order to cool the molded product at a high temperature and minimize shrinkage of the container, it is desirable to design the blow mold so that the temperature of the molded product can be cooled to 1 to 20°C by circulating coolant in the blow mold. do.

Hereinafter, the manufacturing method of an eco-friendly container with excellent chemical resistance according to the present invention and the physical properties of the eco-friendly container manufactured by the manufacturing method will be described using examples.

<Example 1>

Mix 100 parts by weight of high-density polyethylene, 50 parts by weight of eco-friendly filler (calcium carbonate made from eggshell), and 10 parts by weight of colorant (masterbatch mixed with 100 parts by weight of high-density polyethylene and 15 parts by weight of titanium oxide), and add 5 heater bands (the first one). 192℃, second 215℃, third 225℃, fourth 215℃, fifth 240℃) and melted in an injection blow molding machine equipped with a screw. After melting, the molten mixture in the injection mold was pressured at 350 psi for 7 seconds. After injection, the container inlet is cooled to 50℃, the body is 95℃, and the bottom is 90℃ for 2 seconds. The cooled mixture is transferred to a blow mold, the blow mold is closed, air is supplied for 8.5 minutes, blow molded, and blown. The molded product was cooled to 10°C to produce an eco-friendly container with excellent chemical resistance.

<Example 2>

Proceed in the same manner as Example 1 above, but

An eco-friendly container with excellent chemical resistance is manufactured by containing 0.1 parts by weight of antioxidant {octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate} compared to 100 parts by weight of high-density polyethylene. did.

<Example 3>

Proceed in the same manner as Example 1 above, but

An eco-friendly container with excellent chemical resistance was manufactured by adding 2 parts by weight of Teflon-based resin (polytetrafluoroethylene) compared to 100 parts by weight of high-density polyethylene.

<Example 4>

Proceed in the same manner as Example 1 above, but

0.1 part by weight of antioxidant {octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate} and Teflon-based resin (polytetrafluoroethylene) relative to 100 parts by weight of high-density polyethylene. By adding 2 parts by weight, an eco-friendly container with excellent chemical resistance was manufactured.

<Comparative Example 1>

Mix 100 parts by weight of high-density polyethylene, 20 parts by weight of calcium carbonate, and 10 parts by weight of colorant (masterbatch mixed with 100 parts by weight of high-density polyethylene and 15 parts by weight of titanium oxide), and heat five heater bands (the first at 192℃, the second at 215℃, and the third at 225℃). ℃, fourth 215℃, fifth 240℃) and melted in an injection blow molding machine equipped with a screw, and then injected the molten mixture into the injection mold at a pressure of 350 psi for 7 seconds, and then injected the mixture into the injection mold at 50 psi. ℃, cool to 95℃ for the body and 90℃ for the bottom for 2 seconds, transfer the cooled mixture to the blow mold, close the blow mold, supply air for 8.5 and blow mold it, and cool the blow molded product to 10℃. A container was manufactured.

<Comparative Example 2>

The same procedure as in Comparative Example 1 was carried out, but a container was prepared by mixing 80 parts by weight of calcium carbonate.

The drop impact resistance, loading strength, and appearance of the containers manufactured through Examples 1 to 4 and Comparative Examples 1 to 2 were measured and are shown in Table 1 below.

{However, the drop impact resistance was conducted according to UN standards. This is a method of checking for damage or leakage of the container by filling it with room temperature water up to the 20L mark, putting a stopper on it, and dropping it 5 times from a certain height to check for damage or leakage. A method of indicating the maximum height was used.

In addition, the loading strength was determined by checking whether cracks occurred in the container after leaving it for 28 days at 40℃ and under a load of 250kg.

In addition, the appearance was observed with the naked eye to check whether melt fractures or die lines were found to determine whether it was good or bad.}

<Table 1>

As shown in Table 1, it can be seen that the eco-friendly containers manufactured through Examples 1 to 4 of the present invention not only have excellent mechanical strength, but also have excellent appearance quality. In particular, in the case of Examples 3 to 4 containing Teflon-based resin, it can be seen that the appearance quality is more excellent.

Therefore, the method of manufacturing an eco-friendly container with excellent chemical resistance according to the present invention not only has excellent mechanical properties, chemical resistance, and appearance quality, but also provides an eco-friendly container by using calcium carbonate made from eggshell.

S101 ; Raw material mixing stage
S103 ; melting stage
S105 ; Injection stage
S107 ; Blow molding stage
S109 ; Cooling stage

Claims (7)

A raw material mixing step of mixing high-density polyethylene, eco-friendly fillers, and colorants;
A melting step of putting the mixture prepared through the raw material mixing step into an injection blow molding machine and melting it;
An injection step of injecting the molten mixture through the melting step;
A blow molding step of blow molding the mixture injected through the injection step; and
It consists of a cooling step of cooling the molded product manufactured through the blow molding step,
A method of manufacturing an eco-friendly container with excellent chemical resistance, wherein the eco-friendly filler is calcium carbonate made from eggshell.
In claim 1,
The raw material mixing step is a method of manufacturing an eco-friendly container with excellent chemical resistance, characterized in that it consists of 100 parts by weight of high-density polyethylene, 40 to 60 parts by weight of eco-friendly filler, and 5 to 15 parts by weight of colorant.
In claim 1 or 2,
In the raw material mixing step, 0.05 to 0.2 parts by weight of antioxidant is additionally contained relative to 100 parts by weight of the high-density polyethylene,
The antioxidants include octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris(2,4-di-tert-butylphenyl)phosphite, and oxidized A method of manufacturing an eco-friendly container with excellent chemical resistance, characterized in that it is made of at least one selected from the group consisting of bis(hydrogenated tallow alkyl)amine.
In claim 1 or 2,
A method for manufacturing an eco-friendly container with excellent chemical resistance, characterized in that in the raw material mixing step, 0.5 to 3 parts by weight of Teflon-based resin is added compared to 100 parts by weight of high-density polyethylene.
In claim 4,
A method of manufacturing an eco-friendly container with excellent chemical resistance, wherein the Teflon-based resin is made of at least one selected from the group consisting of polytetrafluoroethylene, ethylenetetrafluoroethylene copolymer, and fluorinated ethylenepropylene copolymer.
In claim 1 or 2,
A method of manufacturing an eco-friendly container with excellent chemical resistance, characterized in that the eco-friendly filler is dried for 40 to 60 minutes at a temperature of 70 to 80 ° C.
In claim 1,
The injection step is a method of manufacturing an eco-friendly container with excellent chemical resistance, characterized in that the mixture molten through the melting step is injected into an injection mold for 6 to 8 seconds at a pressure of 300 to 400 Psi.