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How to ensure the suitable heat sealing strength of the facial mask packaging

Aug 08,2021

Source: Link Testing Instruments Co.,Ltd.

With the development of the beauty industry and the increase of people's requirements for beauty and skin care, facial masks have almost become one of the must-have skin care products for beauty lovers. There are four common types of facial masks: mud paste, tear-off, jelly and wet wipes. The reason why the facial mask has a beauty effect is mainly to use the short time it covers the face to isolate the face from the outside air and pollutants for a short time, and it can increase the temperature of the skin, expand the pores of the skin, and promote the secretion and secretion of sweat glands. Metabolism increases the oxygen content of the skin, which helps to eliminate the products of surface cell metabolism and accumulated oils. The effective ingredients in the mask penetrate into the stratum corneum of the epidermis with moisture, and the skin becomes soft, naturally bright and elastic.

Judging from the principle that the above-mentioned facial mask exerts its beauty effects, the amount of moisture carried by the facial mask itself is one of the important factors affecting its use effect. If the moisture in the facial mask is less, the speed of the nutrients or essences entering the skin with the moisture will be greatly reduced. , If the moisture content in the mask is very small, it may even absorb moisture from the skin. In the circulation process of the packaged finished mask, the amount of moisture in the mask is closely related to the barrier and tightness of the package. The low barrier and poor sealing of the package will lead to a large loss of water dispersion in the mask, with residues in it. The moisture content is reduced. The heat-sealing effect of the heat-sealing of the packaging bag directly affects the overall sealability of the mask packaging, so improving the heat-sealing strength of the packaging is an important measure to keep the mask moist during storage and sales.

Test methods and test instrument

The test process is based on the American standard ASTM F2029, and the domestic test standard for the heat-seal performance of flexible plastic packaging is in the process of being formulated. The testing equipment used is the LST-H3 heat seal tester and LTS-05 electronic tensile testing machine independently developed and produced by Link Testing Instruments Co.,Ltd.

Heat Seal Tester LTH-H3
Auto Tensile Tester LTS-05

Test principle:

The test principle of this test is to heat seal the test samples under different heat sealing parameters, and then test the heat seal strength of the heat-sealed samples. According to the tested heat seal strength value and the appearance state of the sample surface, a comprehensive judgment is made. Choose the appropriate heat-sealing parameters to ensure that the sample has the appropriate heat-sealing strength.

The different heat-sealing parameters (heat-sealing temperature, heat-sealing pressure, heat-sealing time) required for heat-sealing the sample can be set by the LTH-H3 heat-sealing tester, and the free ends of the two sides of the heat-sealed sample are respectively set Clamped in the upper and lower clamps of the LTS-05 electronic tensile testing machine. The upper clamp of the device can move upwards at a set speed, while the lower clamp is fixed. The heat-sealed part of the sample follows the upper The upward movement of the fixture is peeled and destroyed. The force and displacement generated during the failure of the sample are monitored in real time by the force sensor in the upper fixture and the displacement sensor inside the device. The device reports the force value data according to the real-time monitoring. The heat seal strength of the sample.

Test sample and test process

Test sample: The test sample used in the test is a certain brand of facial mask packaging aluminum-plastic composite film.

Experimental procedure:

(1) Cut 48 samples with a width of 15.0 mm and a length of about 20 cm along the longitudinal direction of the test sample.

(2) Start the heat sealing tester, set the heat sealing time to 1 s, heat sealing pressure to 0.30 MPa, and heat sealing temperature to 135°C.

(3) After the equipment reaches the set heat sealing parameters, 6 samples are randomly selected, each 2 samples are a group, and the hot covers are placed in the heat sealing instrument relative to each other (in contact with each other), step on the foot switch, The lower heat-sealing head is closed and heat-sealed. After the heat-sealing time is reached, the two heat-sealing heads are automatically separated and the sample is heat-sealed. A total of 3 sets of heat-sealed samples were obtained.

(4) Each time the subsequent heat-sealing temperature increases by 10°C, follow the steps in (3) to heat-seal to obtain 3 sets of samples.

(5) Turn on the intelligent electronic tensile testing machine and set parameters such as sample width, sample thickness, and test speed.

(6) Clamp the two free ends of the heat-sealed sample in the upper and lower clamps of the equipment, so that the long axis of the sample is parallel to the center lines of the upper and lower clamps. Click the test option to start the test. The equipment automatically records and displays the force value generated during the upward movement of the upper clamp in real time, and reports the measured heat seal strength value after the test is over.

(7) Test the heat-sealing strength of all heat-sealed samples according to the steps in (6), and record it at the corresponding heat-sealing temperature.

Test results and analysis

The tested aluminum-plastic composite film for facial mask packaging showed shrinkage on the surface of the heat-sealed part after 185℃, and the heat-sealing strength no longer increased, and there was a tendency to decrease. At 165 ~ 185℃, the surface of the sample after heat-sealing was flat , The heat sealing strength can reach above 31.6N/15mm, the sealing effect is good, and it can ensure that no air leakage occurs at the heat sealing of the packaging bag. Therefore, the best heat-sealing temperature of the samples tested in this article can be controlled between 165 ~ 185℃.

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