KR101388599B1 - Gas permeability measurement apparatus and the measuring method thereof - Google Patents

Abstract

The present invention relates to an apparatus and a method for measuring gas permeability of a packaging film. The apparatus for measuring gas permeability of a packaging film according to the present invention comprises: multiple gas cylinders for storing different kinds of gases; a gas mixer for manufacturing mixed gas by mixing gases provided from the gas cylinders; a first measurement module for measuring gas permeability of a packaging film having a first gas permeability range using mixed gas provided from the gas mixer; and a second measurement module for measuring gas permeability of a packaging film having a second gas permeability range less than the first gas permeability range using the mixed gas provided from the gas mixer. As such, by selectively applying a proper measurement according to the material and thickness of a packaging film as well as the existence of a boring, an effective measurement of gas permeability with respect to various kinds of packaging films and a reduction of measurement time are made possible.

Description

GAS PERMEABILITY MEASUREMENT APPARATUS AND THE MEASURING METHOD THEREOF}

The present invention relates to a gas permeability measuring device and a measuring method, and more particularly to a gas permeability measuring device for measuring the gas permeability of a packaging film for packaging agricultural products and a measuring method using the same.

In general, when packaging a food, sufficient consideration is required regarding the permeability of the gas to the packaging material, such as prevention of oxidation of the contents, prevention of drying or moisture absorption, and prevention of adsorption of fragrance that is transferred from the outside. Recently, MA (Modified Atmosphere) packaging technology has been used to maintain the freshness of fresh produce such as fruits and vegetables and to extend the shelf life.

MA packaging is an effective way to prolong storage and shelf life by inhibiting fresh produce breathing. However, when the equilibrium gas composition inside the package is maintained below the oxygen concentration limit of the storage, storage phenomena such as odor and discoloration due to anaerobic respiration may occur. Information about the gas permeability of the film used is essential to predict the gas composition inside the MA package suitable for respiration of agricultural products.

However, in the case of measurement equipment that is currently commercialized, a film having a high gas permeability such as a microperforated film may be impossible to measure, and may be measured only at room temperature without varying the measurement temperature. In addition, in order to measure oxygen permeability and carbon dioxide permeability, a problem arises in that a different measuring device has to be purchased for each gas.

Accordingly, the present invention has been made in view of the above problems, and the present invention provides a gas permeability measuring apparatus and a measuring method capable of accurately and quickly measuring gas permeability for various kinds of packaging films.

Gas permeability measuring device for packaging film according to an aspect of the present invention, a plurality of gas cylinders for storing different types of gas, a gas mixer for mixing the gas supplied from the gas cylinder to produce a mixed gas, the gas A first measurement module for measuring gas permeability of the packaging film having a first gas permeability range using a mixed gas supplied from a mixer, and a lower than the first gas permeability range using a mixed gas supplied from the gas mixer; It includes a second measurement module for measuring the gas permeability of the packaging film having a range of two gas permeability.

The gas cylinders may include at least one of a first cylinder for storing nitrogen, a second cylinder for storing oxygen, and a third cylinder for storing carbon dioxide.

The first measuring module may include a quasi-isostatic measuring module.

The second measuring module may include a pressure measuring module.

The apparatus may further include a buffer tank installed between the gas mixer and the first and second measurement modules.

Gas permeability measuring method of the packaging film according to an aspect of the present invention, the step of selecting any one of the quasi-isostatic measurement module and pressure measurement module by determining the material, thickness and perforation of the packaging film, through the selected measurement module In order to measure the gas permeability of the packaging film, preparing a mixed gas through a gas mixer using gases supplied from a plurality of gas cylinders storing different kinds of gases, and the mixed gas produced in the gas mixer Supplying to the selected measuring module to measure the gas permeability of the packaging film.

When the selected measuring module is the quasi-pressure type measuring module and the packaging film is an unperforated film, a mixed gas including 7% carbon dioxide and 93% nitrogen may be prepared using the gas mixer.

When the selected measuring module is the quasi-isostatic measuring module and the packaging film is a perforated film, a mixed gas including 20% carbon dioxide and 80% nitrogen may be prepared using the gas mixer.

The mixed gas produced in the gas mixer may be supplied to the selected measurement module via a buffer tank.

According to such a gas permeability measuring device and measuring method, by selectively applying a suitable measuring method according to the material, thickness and perforation of the packaging film, it is possible to measure the effective gas permeability for various kinds of packaging film and to shorten the measurement time You can. In addition, the gas permeability of the film that changes with temperature can be measured in accordance with the storage and distribution temperature range to implement a precise MA packaging design.

1 is a block diagram showing the configuration of a gas permeability measuring device according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a configuration of the first measurement module illustrated in FIG. 1.
Figure 3 is a graph showing the results of measuring the gas permeability of the perforation density of the microperforated film by using a quasi-pressure measuring module.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, It will be possible. The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, the terms "comprising" or "having ", and the like, are intended to specify the presence of stated features, integers, steps, operations, elements, parts, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, parts, or combinations thereof. The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

1 is a block diagram showing the configuration of a gas permeability measuring device according to an embodiment of the present invention.

1, a gas permeability measuring apparatus according to an embodiment of the present invention mixes and mixes gases supplied from a plurality of gas cylinders 100 and gas cylinders 100 storing different kinds of gases. A gas mixer 200 for preparing a gas, a first measurement module 300 for measuring gas permeability of a packaging film using a mixed gas supplied from the gas mixer 200, and a mixed gas supplied from the gas mixer 200. The second measurement module 400 for measuring the gas permeability of the packaging film in a different manner from the first measurement module 300 by using a. In addition, the gas permeability measuring device may further include a buffer tank 500 installed between the gas mixer 200 and the first and second measurement modules 300 and 400.

The gas cylinder 100 is a container for separately storing a gas used for gas permeability measurement, for example, a first cylinder 110 for storing nitrogen (N) and a second for storing oxygen (O ₂ ). At least one of the cylinder 120 and the third cylinder 130 for storing carbon dioxide (CO ₂ ).

The gas mixer 200 mixes one or more kinds of gases supplied from the gas cylinders 100 selected according to the measurement conditions of the packaging film to be measured to produce a mixed gas. The gas mixer 200 is measured by adjusting the type and composition ratio of the gas according to which of the first measurement module 300 and the second measurement module 400 are used or the material, thickness and perforation of the packaging film to be measured. Prepare a mixed gas suitable for.

The mixed gas produced by the gas mixer 200 is supplied to the first measurement module 300 or the second measurement module 400 via the buffer tank 500. The first measurement module 300 receives the mixed gas through the first mixed gas delivery pipe 510 connected to the buffer tank 500, and the second measurement module 400 is provided from the first mixed gas delivery pipe 510. The mixed gas is supplied through the branched second mixed gas delivery pipe 520.

The first measurement module 300 measures the gas permeability of the packaging film having a relatively high first gas permeability range by using the mixed gas supplied from the gas mixer 200. The first measuring module 300 is a device suitable for measuring a kind of packaging film such as a microperforated film having a high gas permeability, and is composed of, for example, a quasi-isostatic measuring module.

FIG. 2 is a diagram illustrating a configuration of the first measurement module illustrated in FIG. 1.

1 and 2, the first measurement module 300 mounts a film in a stainless chamber 310 in which gas tightness is maintained, and installs a ball valve to flow a gas to be measured in the chamber 310. It is configured to replace the gas composition inside the chamber 310. The gas sample inside the chamber 310 may be analyzed by gas chromatography by periodically collecting the gas sample inside the chamber 310 by using a gas tight seal on the septum attached to the film. The oxygen sensor 320 and the carbon dioxide sensor 330 are installed in the chamber 310 to monitor the change in the gas concentration in the chamber 310 and measure the change in the gas concentration in the chamber 310 over time. In terms of gas permeability. For example, the oxygen sensor 320 may be an electrochemical sensor, and the carbon dioxide sensor 330 may be a non-dispersive infrared (NDIR) sensor.

Gas permeability conversion of the quasi-pressure type measurement module 300 can be converted by using the following equations (1) and (2) by regression analysis of the change in oxygen and carbon dioxide concentration in the measured chamber as an exponential function for the measurement time. have.

(Wherein kco ₂ : CO ₂ permeability of the film (mol m ⁻² s ⁻¹ Pa ⁻¹ ),

en ₂ : O ₂ permeability of the film (mol m ^-2 s ^-1 Pa ^-1 ), pco ₂ : partial pressure of CO _{2 in the} chamber (Pa),

pco _2e : partial pressure of CO ₂ in air (Pa), pco _2i : initial partial pressure of CO ₂ (Pa),

po ₂ : O ₂ partial pressure in the chamber (Pa), po _2e : O ₂ partial pressure in the air (Pa),

po _2i : Initial O ₂ partial pressure (Pa), Pa: Atmospheric pressure (Pa),

t: time (s), V: volume of the chamber (m ³ ), A: area of the film (m ² ))

The second measurement module 400 measures the gas permeability of the packaging film having a second gas permeability range lower than the first gas permeability range using the mixed gas supplied from the gas mixer 200. The second measuring module 400 is a device suitable for measuring a packaging film having low gas permeability, and is configured of, for example, a pressure measuring module. The pressure measuring module 400 receives oxygen, carbon dioxide, nitrogen, or a mixed gas thereof from the gas mixer 200, and measures the pressure change of the manometer according to the gas passing through the film to convert it into gas permeability. . The pressure measuring module 400 has a feature that the measuring speed is relatively higher than that of the quasi-equal pressure measuring module 300.

Gas permeability conversion of the pressure measurement module 400 can be converted using the following equation (3).

(Where, P _A: film transmission rate ^{(cc / m 2 · day)} , Q A: volume of the gas permeable,

x: thickness, A _O : cross-sectional area, t: time, P _A1 : partial pressure of high concentration part,

P _A2 : partial pressure of low concentration part)

The method of measuring the gas permeability of the packaging film using the gas permeability measuring apparatus which has such a structure is demonstrated.

First, by determining the material, thickness and perforation of the packaging film to be measured to select whether to measure the quasi-isostatic measuring module 300 and the pressure measuring module 400. For example, when the packaging film to be measured has a high gas permeability, such as a microperforated film, the quasi-isostatic measuring module 300 is selected. When the packaging film to be measured has a low gas permeability, the pressure measuring module 400 is selected. Select). If the film having a high gas permeability is measured by the pressure measuring module 400, since the pressure change of the gas passing through the film is large, it is difficult to obtain accurate measurement data, and the film having a low gas permeability is a semi-isostatic measuring module 300. ), The measurement time becomes too long. Therefore, by selecting a measurement module suitable for the measurement according to the type of film to be measured, it is possible to more effectively measure the gas permeability of the packaging film in terms of measurement accuracy and measurement time.

After the selection of the measurement module, in order to measure the gas permeability of the packaging film through the selected measurement module, the gas mixer 200 using the gases supplied from the plurality of gas cylinders 100 for storing different types of gas. To produce a mixed gas. The composition of the mixed gas is determined in consideration of the difference in nitrogen diffusion, the permeation rate of oxygen and carbon dioxide. For example, when the selected measuring module is a quasi-isostatic measuring module 300 and the packaging film to be measured is a non-perforated film, a mixture including 7% carbon dioxide and 93% nitrogen using the gas mixer 200 is used. Prepare the gas. In addition, when the selected measuring module is a quasi-pressure type measuring module 300, and the packaging film to be measured is a perforated film, a mixed gas containing 20% carbon dioxide and 80% nitrogen is prepared using the gas mixer 200. do. On the other hand, when the selected measurement module is a pressure measurement module 400, the gas mixer 200 may supply an individual gas such as oxygen, carbon dioxide, nitrogen or a mixed gas mixed with these gases.

Thereafter, the mixed gas prepared in the gas mixer 200 is supplied to the selected measurement module to measure the gas permeability of the packaging film. In this case, the mixed gas produced by the gas mixer 200 may be supplied to the selected measurement module via the buffer tank 500.

On the other hand, if it is difficult to determine the material, thickness and perforation of the packaging film, the gas permeability is first measured using the pressure measuring module 400, which has a fast measuring time, and the quasi-isostatic type when there is an error in the measured data value. By measuring the gas permeability again using the measurement module 300, the measurement time can be shortened.

Figure 3 is a graph showing the results of measuring the gas permeability of the perforation density of the microperforated film by using a quasi-pressure measuring module.

Referring to FIGS. 1 and 3, the punching density (147 pieces / m 2, 440 pieces / m 2, 806 pieces) of the laminated film (PP + EVOH + PE, thickness 0.025mm) using the quasi-isostatic measurement module 300 is shown. Gas permeability was measured for each m 2). In this case, a mixed gas of 20% carbon dioxide or oxygen and 80% nitrogen was used as the mixed gas. In FIG. 3, (a) is 4 degreeC, (b) is 8 degreeC, and (c) is the result measured on temperature conditions of 12 degreeC.

The gas permeability measurement showed that the higher the permeation density, the higher the permeability of oxygen and carbon dioxide. In general, in the case of synthetic resin film, the permeability of carbon dioxide having high solubility is higher than that of oxygen, but in the gas permeability of the microperforated film, the oxygen permeability is higher than that of carbon dioxide. This phenomenon is interpreted to appear due to the effect of external partial pressure rather than gas solubility due to microporation.

Oxygen and carbon dioxide permeability were measured by three different perforation densities, and the regression analysis showed that the results were regressed as a first order function. The crystal coefficient value was very high, above 0.99. It was confirmed that it is possible to convert oxygen and carbon dioxide permeability by density.

[Table 1] is the oxygen permeability measurement results of the standard film (Polyester, thickness 0.027mm) was measured in the temperature conditions 17 ℃, 27 ℃, 37 ℃ using the pressure measuring module 400.

division Measuring temperature
(℃) Standard Film Oxygen Permeability
(cc / m2day) One 17 50.6 ± 5.1 2 27 163.1 ± 20.3 3 37 242.6 ± 5.1

Referring to [Table 1], when the oxygen permeability was measured at 17 ° C. using the pressure measuring module 400, the oxygen permeability of the standard film was measured as 50.6 compared to 47.6, and similar results were confirmed. In addition, the regression analysis results of the oxygen permeability of the standard film belonging to the lower gas permeability by temperature section, but the result of the coefficient of determination is 0.99 or more, which is consistent with the general tendency that the gas permeability increases with increasing temperature It was confirmed.

As described above, by selectively applying a suitable measuring method according to the material, thickness and perforation of the packaging film, it is possible to measure the effective gas permeability for various kinds of packaging films and to shorten the measurement time. In addition, the gas permeability of the film that changes with temperature can be measured in accordance with the storage and distribution temperature range to implement a precise MA packaging design.

While the present invention has been described in connection with what is presently considered to be practical and exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

100: gas cylinder 200: gas mixer
300: quasi-isostatic measuring module 400: pressure measuring module
500: buffer tank

Claims (10)

A plurality of gas cylinders storing different kinds of gases;
A gas mixer for mixing gas supplied from the gas cylinders to produce a mixed gas;
A quasi-isostatic type measurement module for measuring the gas permeability of the packaging film having a first gas permeability range using the mixed gas supplied from the gas mixer; And
Apparatus for measuring the gas permeability of the packaging film comprising a pressure measuring module for measuring the gas permeability of the packaging film having a second gas permeability range lower than the first gas permeability range using the mixed gas supplied from the gas mixer. The method of claim 1,
The gas cylinders are gas permeability measuring apparatus of the packaging film comprising at least one of a first cylinder for storing nitrogen, a second cylinder for storing oxygen and a third cylinder for storing carbon dioxide. delete delete The method of claim 1,
Apparatus for measuring the gas permeability of the packaging film further comprises a buffer tank installed between the gas mixer and the first and second measurement module. Selecting a quasi-isostatic pressure measuring module in the case of a packaging film having a first gas permeability range, and selecting a pressure measuring module in the case of a packaging film having a second gas permeability range lower than the first gas permeability range;
Preparing a mixed gas through a gas mixer using gases supplied from a plurality of gas cylinders storing different kinds of gases to measure gas permeability of the packaging film through the selected measuring module; And
And measuring gas permeability of the packaging film by supplying the mixed gas prepared in the gas mixer to the selected measurement module. The method according to claim 6,
Said gas cylinder comprises at least one of a first cylinder for storing nitrogen, a second cylinder for storing oxygen and a third cylinder for storing carbon dioxide. The method according to claim 6,
When the selected measuring module is the quasi-pressure type measuring module, and the packaging film is an unperforated film, a mixed gas containing 7% carbon dioxide and 93% nitrogen is prepared using the gas mixer. Method of measuring gas permeability. The method according to claim 6,
When the selected measuring module is the quasi-isostatic measuring module, and the packaging film is a perforated film, the gas of the packaging film, characterized in that for producing a mixed gas containing 20% carbon dioxide and 80% nitrogen using the gas mixer. Permeability measurement method. The method according to claim 6,
Method for measuring the gas permeability of the packaging film, characterized in that for supplying the mixed gas produced in the gas mixer to the selected measuring module via a buffer tank.

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