JPS6024419B2 - Moisture permeability measuring device for polymer packaging materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a moisture permeability measuring device for polymer packaging materials that measures the moisture permeability of polymer packaging materials used as packaging materials for foods, medicines, etc. .

'o'Prior art As a conventional device for measuring moisture permeability of polymer packaging materials,
A highly hygroscopic desiccant is placed in a measuring container made of the material to be measured, and the measuring container is placed in a humidity-controlled space and the weight of the container is measured at regular intervals. The so-called cup method (J
ISZ 0208) or bag method (JISZ 0222), or to make such measurements self-recording, a thermobalance is used to continuously measure the weight of the measuring container by flowing overflowing gas into the measuring container environmental space. There are things to do.

With such an apparatus, i) the measurement takes time because it is a discontinuous method in which a moisture-permeable sample is taken out at an arbitrary point and its weight change is determined; ii) Requires a complex mechanism to adjust the humidity of the airflow. iii) There were drawbacks such as a limited humidity control range. In addition, in these methods, it is often difficult to determine whether a change in the moisture absorption capacity of the moisture absorbent is due to a change in temperature or a change in relative humidity, resulting in a problem in measurement accuracy. One object of the present invention is to solve the above-mentioned problems with the conventional apparatus, eliminate the need for the use of a moisture absorbent or a complicated airflow humidity control mechanism, and keep the relative humidity of water vapor permeating the material to be measured constant regardless of temperature changes. The purpose of the present invention is to provide a moisture permeability measuring device that can improve measurement accuracy by making it possible to ignore the influence of changes in relative humidity on measured values, and can measure and evaluate the moisture permeability of a polymer packaging material as a function of temperature or time.

0 configuration The device for measuring moisture permeability of polymer packaging materials according to the present invention is configured such that the polymer packaging material to be measured constitutes at least a part of the container wall, and a saturated inorganic salt aqueous solution is housed inside the device. a means for controlling and heating the container; a means for measuring the weight of the container; a sealed chamber for sealing the environmental space of the container in a state where the container is equipped with the above-mentioned means; and a dry gas in the sealed chamber. It is also constructed by providing means for distributing the information.

Therefore, a container in which the polymer packaging material to be measured constitutes at least a part of the container wall and which contains a saturated inorganic salt aqueous solution is flooded to a constant temperature by a controlled heating means. Then, the saturated inorganic salt aqueous solution in the container steams and becomes water vapor. This water vapor permeates the polymer packaging material to be measured due to the gas partial pressure difference inside and outside the container, and enters the sealed chamber that seals the environmental space including the container. The water vapor that has entered the sealed chamber is discharged outside the system by means of circulating dry gas. The weight of the entire container decreases by this amount of discharge, and such weight change is measured by the weight measuring means of the container. In this way, the constituent means work together, and the relative humidity of the evaporated water vapor of the saturated inorganic salt aqueous solution is maintained at a constant value regardless of the temperature. Changes in weight can be measured, and therefore the water vapor permeability of the polymeric packaging material to be measured can be measured continuously. EXAMPLE A moisture permeability measuring device for polymer packaging materials, which is an example of the present invention, will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram showing the configuration of an embodiment of the present invention. In the figure, the container 1 consists of a container main body 2 made of a material that will not be corroded by the liquid contained in it, and a lid 3 that can be attached and detached in a hermetically sealed manner via a ring or the like, as shown in FIG. 4 is fitted with a packaging material sample film 11 to be measured. Inside this container 1, a saturated inorganic salt aqueous solution 12, for example, NaCI, is stored in an amount of several to several dozen. As will be described later, the saturated inorganic salt aqueous solution has a property that the relative humidity is approximately constant within the temperature range to be measured. This container 1 is placed on the counter 21 of a thermobalance as a thermogravimetric measuring device in thermal analysis. As shown in the figure, the thermotube includes a beam 22 for suspending a rack 21, a balance mechanism 23, and an unbalance detection mechanism 24.
It is composed of an automatic balance control circuit 26 and a recorder 25. Also equipped are a heating device 40 for heating a portion of the container, a thermocouple 41 for detecting temperature, and a temperature control device 42 for controlling the temperature according to a program. Furthermore, container 1
The environmental space including the weight and the balance mechanism for measuring its weight is sealed by a sealed chamber 301. The sealed chamber 30 is provided with a drying gas inlet 31 and its outlet 32 . The drying gas is introduced from the inlet 31 into the container 1.
A fluid connection is made so that the environmental space is a dry atmosphere and is discharged from the outlet 32. With the above configuration, the weight change of the container 1 can be continuously measured as a function of temperature or time.

That is, the heating device 40 is controlled by the temperature control device 42 to control the temperature of the container 1.
to a constant temperature. The saturated inorganic salt aqueous solution 12 in the container 1 evaporates and becomes water vapor, which passes through the sample membrane 11 to be measured and enters the sealed chamber 30 due to the gas partial pressure difference inside and outside the container. Inside the sealed chamber 30, dehydrated dry gas is introduced into the inlet 31.
Since the water vapor that has permeated is immediately discharged out of the system, the relative humidity difference between the inside and outside of the sample membrane 11 becomes constant. Sample film to be measured 1
Since the water vapor that has passed through the container 1 is thus discharged to the outside of the thread, this amount of discharge decreases the overall weight of the container 1 containing the aqueous solution. Furthermore, even if the container is flooded and several container temperatures are set and measurements are taken at each temperature, the relative humidity of the evaporated water vapor of the saturated inorganic salt aqueous solution remains at a constant value regardless of the temperature. It is not affected by changes in relative humidity at the set temperature. FIG. 3 shows how the recorder 25 records the weight change (%) of the container over time when the container temperature was kept constant at 30° C., 40° C., and 50° C. respectively. FIG. 4 shows a case in which the heating device 40 is controlled to heat the container 1, the container temperature is increased at a constant rate, and the weight change of the container 1 is measured with respect to the temperature change using the same machine as above. According to this device, it is possible to track the weight change of the entire container 1 with respect to a change in time or temperature, thereby making it possible to continuously measure the permeability temperature of the sample membrane 11 to be measured. will be possible. In the above, it was explained that the significance of the saturated inorganic salt aqueous solution is that the relative humidity of its evaporated water vapor is maintained at a constant value regardless of the temperature.
+ day 20, the relative humidity is 75% regardless of temperature
Similarly, in the case of K ratio P040 QO, it is about 93%, and in the case of (N normal) 2S040 Nacl + day 20, it is 6
The relative humidity can be kept constant at about 2%, or about 45% in the case of Cr03, regardless of the temperature.

Container 1 in this device is not of the type shown in the above embodiment, but if the polymer packaging material is the container itself, such as a medicine bottle, a closed small container that can contain the aqueous solution in a non-corrosive manner is prepared separately. It is also possible to put the small container into a medicine bottle and use the entire container as the container 1.

N effect Since the present invention is constructed as described above, it does not require the use of a conventional moisture absorbent or a complicated airflow control mechanism, and it is possible to control the relative humidity of water vapor permeating the material to be measured regardless of temperature changes. It is possible to provide a new moisture permeability measurement device that can measure and evaluate the moisture permeability of polymer packaging materials as a function of temperature or time, with the humidity constant and the influence of changes in relative humidity on the measured value ignored. It is.

In addition, by using a highly sensitive hot water bottle as a means of measuring the weight of the container, the above measurement can be carried out in a shorter time, and the accuracy of the measurement can be improved.
Reliability can be increased. In addition to measuring the moisture permeability of water vapor, the present invention can also be used to measure the permeability of gases such as 02 and CO.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the overall structure of the apparatus of the present invention, Fig. 2 is a front sectional view showing an embodiment of the container in the invention, and Figs. , is a curve diagram showing a change in weight of a sample to be measured over time. DESCRIPTION OF SYMBOLS 1... Container, 11... Packaging material sample membrane to be measured, 12... Saturated inorganic salt aqueous solution, 21...
・・・・Roughness of the main bottle, 22・・・・Beam of the balance, 30・・・・Sealed chamber, 31・・・・Drying air inlet, 32・・・・Drying Air outlet 0, 40...
...Heating device, 42...Temperature control device. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1. A container in which a polymer packaging material to be measured constitutes at least a part of the container wall, and a saturated inorganic salt aqueous solution is housed inside the container, and a means for controlling heating of this container. and a means for measuring the weight of the container, a sealed chamber for sealing the environmental space of the container in a state where the container is equipped with each of the above-mentioned means, and a means for circulating dry gas into the sealed chamber. Moisture permeability measuring device for polymer packaging materials. 2. The container according to claim 1, wherein a part of the wall of the container has a window, and the polymer packaging material to be measured is fitted into the window in an airtight and replaceable manner. Molecular moisture permeability measurement device for packaging materials. 3. The moisture permeability measuring device for polymer packaging materials according to claim 1, wherein the means for measuring the weight of the container is a thermogravimetric measuring device with high detection sensitivity.