KR20080062644A - Multilayered plastic vessel having an excellent antibiosis and gas barrier - Google Patents

Abstract

A multi-layered plastic vessel with high antimicrobial and gas barrier effects is provided to improve antimicrobial and gas barrier effects and transparency by adding nano-silver particles of 50~2,000ppm. A multi-layered plastic vessel with high antimicrobial and gas barrier effects is composed of an inner layer, an outer layer, an oxygen isolating layer, and an absorbing layer. The inner and outer layers are made of resin that nano-silver particles are dispersed. The oxygen isolating layer is formed between the inner and outer layers. The mean particle diameter of the nano-silver particle is 2~100nm. The nano-silver particles of 50~2,000ppm are dispersed. A dispersing agent of the nano-silver particle is at least one or two selected from a group comprising ethylene glycol, dimethyl glycol, and triethylene glycol.

Description

Multilayered Plastic Vessel Having an Excellent Antibiosis and Gas Barrier}

      The present invention relates to a plastic container of a multi-layered structure, and more particularly to a plastic container of a multi-layered structure containing silver nano particles, excellent in antimicrobial properties, gas barrier properties such as oxygen and transparency.

Stretched containers made of polyethylene terephthalate have excellent transparency, impact resistance, light weight, hygiene, adequate barrier and pressure resistance to oxygen or carbon gas, and are carbonated beverages such as cooking oil, sauces, dressings, cooking oil, beer, cola, and cider. It is widely used as a packaging container for beverages, juices, drinking springs, shampoos, cosmetics, fines, and aerosol products.

However, in completely sealed containers such as glass bottles and metal cans, gas permeability is close to zero, while stretched polyester containers tend to be slightly permeable to oxygen, carbon gas and the like, which tends to be disadvantageous in terms of food preservation.

Carbonated beverages such as beer, cola, cider, etc. are lost due to the loss of carbonic acid gas, and the storage period is limited due to the permeation of oxygen from the outside for juice drinks. In addition, especially under high temperature or high humidity conditions, the amount of oxygen permeation increases, which causes many problems as a container containing high temperature contents.

In general, silver nano is a compound word of nanotechnology and silver that deal with materials and devices at the nanometer level. In the nanotechnology described above, silver nanoparticles are granulated into ultrafine particles, and the surface area of the silver nanostate is maximized. By changing to an excellent state, it exhibits very strong sterilization, antibacterial action and deodorizing action.

In particular, when the silver nanoparticles are mixed with water, their sterilization and antimicrobial effects become stronger, thereby suppressing the growth of bacteria or toxic substances. Can be used as an antibiotic.

Accordingly, in recent years, as described above, silver nano is attached to the surface of a container by using a method such as coating silver in a nano state, and thus a method of adding the silver properties as described above is widely used, but the silver nano is not properly dispersed. In this case, the functionality is significantly reduced, and thus, a problem in that the antimicrobial and bactericidal deodorizing effect of silver nano is not greatly highlighted.

The present invention is to solve the problems of the prior art as described above, provides a multi-layered plastic container containing silver nanoparticles excellent in antibacterial, gas barrier properties such as oxygen and transparency.

In order to achieve the above object, the present invention is a plastic container of a multi-layer structure including an inner layer, an outer layer, an oxygen barrier layer and an absorbing layer, wherein the inner layer and outer layer is formed of a resin in which silver nanoparticles are dispersed, the inner layer and outer layer Provided is a plastic container of a multi-layer structure provided with an oxygen barrier layer therebetween.

It is preferable that the average particle diameter of the said silver nanoparticles is 2-100 nm, and it is preferable that the said silver nanoparticles are disperse | distributed in the quantity of 50-2000pppm.

Ethylene glycol, dimethyl glycol, triethylene glycol or a mixture thereof may be used as the dispersant capable of dispersing the silver nanoparticles in the resin, but is not limited thereto.

Examples of the resin include basic resins such as polyester resins, olefin resins, cyclic olefin copolymers, and the like, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyarylate, and copolymers thereof. Blow molding and heat treatment resins include, but are not limited to.

The oxygen blocking layer includes an oxygen blocking barrier, and the oxygen blocking barrier preferably contains a polyamide resin containing a metha xylene group.

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

The plastic container of the multi-layered structure according to the present invention includes an inner layer, an outer layer, and an oxygen barrier layer disposed therebetween. If necessary, an adhesive resin may be included between the oxygen blocking layer and the absorbing layer and the inner and outer layers, and may be formed as illustrated below, but is not limited thereto.

2-layer 3-layer structure: PET / MXD6 / PET

2-layer 5-layer structure: PET / MXD6 / PET / MXD6 / PET

3-layer 5-layer structure: PET / AD / MXD6 / AD / PET

Examples of the basic resin of the plastic container having a multilayer structure according to the present invention include polyester resins, olefin resins, cyclic olefin polymers, and the like. Examples of the olefin resin include polyethylene such as low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, linear ultra low density polyethylene, polypropylene, ethylene-propylene copolymer, and mixtures thereof.

Known resins may be used as the stretch blow molding and heat treatment resins used in the container of the present invention. Specifically, for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyarylate, Copolymers thereof or mixtures of other resins with these resins may be suitably used.

Dispersibility may not be impaired by dispersing nano-sized silver particles using a dispersing agent such as ethylene glycol in the resin by using a melt kneading method among known kneading methods.

The nano-sized silver particles to be added are preferably in the range of 2 to 100 nm in average particle diameter. If the average particle diameter exceeds 100 nm, the haze becomes 15% or more after molding, which impairs transparency. It is very difficult and agglomerates and loses the nano size, which makes it impossible to achieve its original purpose.

In addition, the input amount is preferably 50 to 2,000 ppm based on the weight of the base resin, it is difficult to expect the original effect such as antibacterial when the content of silver nano is less than 50 ppm, haze 15 if it exceeds 2,000 ppm It may cause more than% to compromise transparency.

The oxygen blocking layer of the plastic container of the multi-layered structure according to the present invention includes an oxygen blocking barrier, which has a function of absorbing oxygen to reduce the entry of oxygen into the container to double the antibacterial function.

The method for producing a preform for a plastic container having a multilayer structure according to the present invention is based on the following two steps.

(Stage 1

70 ~ 90 before barrier resin is injected? It is dried in a drier for 4 to 5 hours, at which time the moisture content is maintained at 50 to 400 ppm, preferably 50 to 200 ppm.

(2) step

In the multilayer preform manufacturing process, the temperature of the polyester injection barrel is 290 ~ 295 ℃, the injection barrel of the barrier material is injection molding the multilayer preform under the temperature conditions of 265 ~ 285 ℃.

The moisture-removed resin is transferred from the dryer to the injection machine hopper, and subsequently supplied to the reciprocating screw injection molding machine by a predetermined amount, and then injected into the mold through melt plasticization.

Since a certain time is required for the injection process to be completely completed, a large amount of resin remains in the injection machine hopper, and 100? The above is preferably maintained at 160 ?. In addition, the temperature in the barrier injection machine hopper is 50? Manage as above.

The barrier resin is preferably a polyamide containing a metha xylene group (e.g., NY-MXD6 ^® , Aegis ^® ), and the polyester resin is a terephthalic acid as a dicarboxylic acid component and ethylene glycol as a dihydroxy component. As described above in the known resin produced by esterification or transesterification, liquid polycondensation and solid phase polymerization, silver nanoparticles contain 50 to 2,000 ppm.

When the moisture content of the barrier resin is 50 ppm or less, the polyamide containing the metha xylene group, which is a barrier resin, is not deteriorated or not properly cooled after injection of the preform, and the crystallinity of the barrier layer is increased. Or peeling occurs. In addition, when the moisture content is increased to 400ppm or more, the moisture in the barrier resin acts as a crystal nucleating agent, resulting in excessive crystallinity of the injection-molded preform, which causes peeling problems during blow molding.

If the barrel temperature is too high during injection molding, the preform is not cooled properly after injection, and the crystallinity of the preform is increased, and the barrier resin is carbonized during the manufacturing process of the multi-layer container. Peeling problems will occur.

Silver nano-contained multi-layer plastic container according to the present invention has a 99.9% antimicrobial and haze value of less than 15%, 22 ℃, 50RH% (outside), 90% RH (inside) conditions of 1 ppm oxygen blocking period of 6 months Or longer, preferably 6 to 9 months.

Hereinafter, the present invention will be described in detail with reference to examples, but these examples are only intended to more clearly understand the present invention and are not intended to limit the scope of the present invention.

Example  1: Manufacture of multi-layered plastic containers (1)

Silver nanoparticles were dispersed in ethylene glycol in a polyethylene terephthalate resin to prepare a master chip such that 3000 ppm of silver nanoparticles were contained in a polyester resin.

The final polyester resin by blending silver in the master chip to contain 50ppm at 160 ℃ in a hot-air oven for 4 hours, the barrier resin Aegis ^® resins were respectively dried at 70 ℃ for 4 hours.

The dried resin was set at a temperature of 290 ° C. for the polyester resin and 270 ° C. for the barrier resin using a Kostec 48 cavity multi-injection molding machine, and the content of Aegis ^® resin was 7%. In addition, a multilayer preform containing a barrier resin as an inner layer was molded between polyester outer layers.

Subsequently, the surface temperature of the multi-layer preform was heated by a heater to obtain a primary pressure of 9 bar and a secondary pressure of 40 bar. The stretch blow molding was performed while maintaining the stretching ratio of the horizontal axis twice and the stretching ratio of the vertical axis four times. To prepare a multi-layered plastic container.

Example  2: Manufacture of multi-layered plastic containers (2)

Except that the content of silver nano contained in the final polyester resin to 300ppm was carried out in the same manner as in Example 1 to injection molding a multilayer preform containing a barrier resin as an inner layer between the polyester outer layer.

Subsequently, the surface temperature of the multi-layer preform was heated by a heater to obtain a primary pressure of 9 bar and a secondary pressure of 40 bar. The stretch blow molding was performed while maintaining the stretching ratio of the horizontal axis twice and the stretching ratio of the vertical axis four times. To prepare a multi-layered plastic container.

Example  3: Manufacture of multi-layered plastic containers (3)

Except for setting the content of silver nanoparticles contained in the final polyester resin to 2,000 ppm, the same procedure as in Example 1 was carried out to injection molding a multilayer preform including a barrier resin as an inner layer between the polyester outer layers.

Subsequently, the surface temperature of the multi-layer preform was heated by a heater to obtain a primary pressure of 9 bar and a secondary pressure of 40 bar. The stretch blow molding was performed while maintaining the stretching ratio of the horizontal axis twice and the stretching ratio of the vertical axis four times. To prepare a multi-layered plastic container.

Comparative example  1: Manufacture of multi-layered plastic containers (4)

A polyethylene terephthalate in 160 ℃ 4 hours, the barrier resin Aegis ^® resins were respectively dried at 70 ℃ for 4 hours.

The dried resin was set at a temperature of 290 ° C. for the polyester resin and 270 ° C. for the barrier resin using a Kostec 4-cavity multi-injection molding machine, and the content of Aegis ^® resin was 7%. The multilayer preform containing the barrier resin as the inner layer was injection molded between the polyester outer layers.

Subsequently, the surface temperature of the multi-layer preform was heated by a heater to obtain a primary pressure of 9 bar and a secondary pressure of 40 bar. The stretch blow molding was performed while maintaining the stretching ratio of the horizontal axis twice and the stretching ratio of the vertical axis four times. To prepare a multi-layered plastic container.

Comparative example  2: Manufacture of multi-layered plastic containers (5)

Except that the content of silver nano contained in the final polyester resin to 2,200ppm was carried out in the same manner as in Example 1 to injection molding a multilayer preform containing a barrier resin as an inner layer between the polyester outer layer.

Subsequently, the surface temperature of the multi-layer preform was heated by a heater to obtain a primary pressure of 9 bar and a secondary pressure of 40 bar. The stretch blow molding was performed while maintaining the stretching ratio of the horizontal axis twice and the stretching ratio of the vertical axis four times. To prepare a multi-layered plastic container.

Comparative example  3: Manufacture of single layer plastic container

Silver nanoparticles were dispersed in ethylene glycol in a polyethylene terephthalate resin to prepare a master chip such that 3000 ppm of silver nanoparticles were contained in a polyester resin.

The master chip was blended to contain 2,000 ppm of silver nanoparticles in the final polyester resin and dried at 160 ° C. for 4 hours in a hot air oven.

The dried resin was injection molded into a single layer preform using a Kostec 48 cavity multi-injection molding machine by setting the injection temperature of the polyester resin to 290 ° C.

Subsequently, the surface temperature of the multi-layer preform was heated by a heater to obtain a primary pressure of 9 bar and a secondary pressure of 40 bar. The stretch blow molding was performed while maintaining the stretching ratio of the horizontal axis twice and the stretching ratio of the vertical axis four times. To prepare a multi-layered plastic container.

Experimental Example  1: Opacity evaluation ( Haze )

      After sampling the panel portions of the plastic containers prepared in Examples 1 to 3 and Comparative Examples 1 to 3, a haze meter of Toyo Seiki Co., Ltd., Japan The results of measuring the opacity (haze) of the container are shown in Table 1 below, wherein the transparency is measured by measuring the transparency three times by separating the PET outer layer in the container and cutting it into a size of 20 * 20 mm. It was.

Experimental Example  2: antimicrobial evaluation

The results of evaluating the antimicrobial properties of the plastic containers prepared in Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1 below.

The antimicrobial evaluation was performed by KS K0693, a Korean national standard test method as follows.

①. Test strain used: Staphylococcus aureus ATCC 6538, Escherichia coli ATCC 25922

②. Test condition: Test bacteria after shaking culture for 24 hours at 37 ± 1 ℃ (number of shaking 120 times / min)

③. Test sample weight: 2.0g

④. Neutralization solution: Phosphate buffer solution (pH 7.0 ± 0.2)

⑤. Reduction rate: [(Mb- Mc) / Mb] × 100 (more than 31.6 times)

Ma: Initial number of bacteria in the control sample (average value)

Mb: Number of bacteria in the control sample after incubation for 24 hours (average value)

Mc: number of bacteria (average) of test sample after incubation for 24 hours

Experimental Example  3: Oxygen barrier  evaluation

The results of evaluating the oxygen barrier properties of the plastic containers prepared in Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1 below.

The oxygen barrier evaluation was performed when the oxygen permeability data was stabilized at 22 ° C., 50 RH% (external) and 90% RH (internal) using an oxygen permeability measuring device (Mocon, OXTRAN 2/21) of a plastic container. It was measured three times based on the value of and evaluated by the average value.

      In Table 1 below, the oxygen barrier property means a time at which 1 ppm of oxygen in the plastic container is permeated, and the unit is main.

[Table 1] Property evaluation of plastic containers

As shown in Table 1, the test method for evaluating the antimicrobial properties of the plastic surface of JIS Z 2801-2000 in the Japanese JIS test method (Japanese national standard test method), the antimicrobial activity value is 2.0 or more (that is, 1/100) In the case of having antimicrobial properties, it can be seen that the silver-containing plastic container prepared according to the embodiment of the present invention exhibits an excellent antimicrobial effect of extinction of various bacteria harmful to the human body.

In addition, it can be seen that it takes 6 months or more for the permeation of 1 ppm of oxygen in the beverage and the transparency of the oxygen barrier and the polyester container can be maintained as the opacity of the container is 12% or less. On the other hand, in the case of Comparative Example 2, but good oxygen barrier properties, it can be confirmed that the transparency is poor.

As described above, the multi-layered plastic container according to the present invention is a container excellent in antimicrobial activity, gas barrier properties such as oxygen, and transparency because it contains silver nanoparticles. It can be usefully used.

Claims (9)

     In a multi-layered plastic container including an inner layer, an outer layer, an oxygen barrier layer and an absorber layer, The inner layer and the outer layer is formed of a resin in which silver nanoparticles are dispersed, the plastic container having a multi-layer structure, characterized in that the oxygen blocking layer is provided between the inner layer and the outer layer. The method of claim 1, The average particle diameter of the silver nanoparticles is 2 ~ 100nm, the plastic container of a multi-layer structure, characterized in that the silver nanoparticles are dispersed in an amount of 50 ~ 2000ppm. The method according to claim 1 or 2, Dispersing agent of the silver nanoparticles is a plastic container having a multi-layer structure, characterized in that one or two or more selected from the group consisting of ethylene glycol, dimethyl glycol, triethylene glycol. The multilayer structure according to claim 1, wherein the resin comprises at least one basic resin selected from the group consisting of polyester resins, olefin resins and cyclic olefin copolymers, and resins capable of stretch blow molding and heat treatment. Plastic containers. The method of claim 4, wherein the stretch blow molding and heat treatment resin is at least one member selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyarylate and copolymers thereof. Multilayered plastic container. 2. The plastic container of claim 1, wherein the oxygen barrier layer comprises an oxygen barrier barrier. 7. The plastic container of claim 6, wherein the oxygen barrier barrier contains a polyamide resin containing a metha xylene group. The method of claim 1, wherein the plastic container of the multi-layer structure is 19.9% of antimicrobial and haze value of less than 15%, 22 ℃, 50RH% (external), 90% RH (internal) conditions 1 ppm oxygen blocking period of 6 months or more Multi-layer plastic container, characterized in that. The multi-layer plastic container of claim 8, wherein the 1 ppm oxygen blocking period is 6 months to 9 months.