How to effectively reduce the damage rate of packaging bags under low temperature environment

Soft plastic food packaging products less prone to deterioration in a cold environment, the shelf life can be relatively extended because of the low temperatures inhibit the reproduction and growth and the probability of food nutrients not easily oxidized, so there are moldy, rancidity and other issues of food microorganisms generally lower [ 1,2]. However, a low temperature environment has also brought side effects, reducing the probability of deterioration of the product occurs at the same time, the product will in the transportation, storage and sales process of packaging and sealing integrity of adverse effects. For example, in the production line of frozen dumplings bag rupture phenomenon does not appear, but after after frozen storage bag or seal rupture phenomenon. How to make a low temperature environment, the appropriate choice of packaging materials or packaging materials to improve performance, reduce product breakage rate in a cold environment, food companies are troubled by problems of quality.

At low temperatures, the soft polymer plastic materials have increased brittleness tendency, prone to embrittlement phenomenon. Because at low temperatures, soft plastic packaging segment corresponding molecular mobility of the polymer material to reduce the internal deformation under loads decreased, diminished capacity to resist impact, causing soft plastic packaging reduces flexibility, fragility, namely packaging material flexibility and impact resistance at low temperatures deteriorates, resulting in intolerance external shocks occurred broken bags, leak, etc. breakage. In order to improve the soft plastic packaging material at a low temperature embrittlement is not easy, you need to feed their inner join toughening additive such as, but exactly how cold, can withstand low temperatures, cold resistance should be verified by testing.

Is obtained by pendulum impact resistance at a relatively low temperature and the standard ambient conditions (mostly minus 18 ℃) under the test could, as cold is not less than a certain fixed percentage ratio (for example BOPA / LDPE composite film cold required not less than 60%), then the packaging material at low mechanical strength obvious physical deterioration does not occur, as the lower the ratio, the worse the material described cold.

First, the test method and apparatus

1. Test equipment

FIT-01 Film Impact Tester (Labthink blue light): According to the principle of conservation of energy research and development. Semicircular instrument punch at a certain speed and impact through the membrane specimen, according to the energy consumed by the punch, and thus anti-pendulum impact evaluation capability of the film.

Impact energy equipment have 1J, 2J, 3J three ranges, and can be extended to 5J, a resolution of 0.01 J; punch diameter divided Φ25.4mm, Φ19mm, Φ12.7mm are three sample clip mouth diameter Φ89mm, Φ60mm two kinds; and pneumatically clamping the specimen. In addition the device can be used for precise determination of material plastic film, sheet, composite film, foil and other anti-pendulum impact energy, but also for paper, cardboard and other anti-pendulum impact energy test smoke Metallized paper bag, Tetra Pak paper packaging plastic composite film.

Figure 1FIT-01 film impact tester

2. test procedure

Anti-pendulum impact test method to be tested in the cold can reference GB8809 "plastic film anti-pendulum impact test method."

(1) cutout

Respectively, from No. 1, No. 2 specimen surface and cut 10cm × 10cm sample each 20, and placed in 23 ± 2 ℃, at least 4h at 45% ~ 55% RH environment.

(2) Thickness

Thickness of the sample were tested No.1 2. The center position of the test specimen of each point, the thickness of the two samples were collected from 20 samples the arithmetic mean of the test results.

(3) low temperature

The two samples from each of 10 randomly-cut sample into -18 ℃ low temperature environment 2h.

(4) Equipment Calibration

Selection of appropriate diameter punch and impact range, so that the test results of the sample between 10% to 90% range is selected. The test selected diameter Φ12.7mm punch, sample jaws diameter Φ89mm, the impact of the range of 3J. In accordance with the requirements of the equipment calibration.

(5) test specimens at room temperature

The specimen in the clamping device, depress the gas pedal, the clamp specimen. Click the Test option, punch down, impact of the sample, the device automatically displays the test results of the sample. This operation is repeated until the 1st, 10 samples Sample No. 2, without low temperature tests were completed.

(6) low temperature sample test

After the sample cold treatment is complete, remove, according to (5) of the step test.

Second, the results and discussion

Pendulum impact resistance of the film after -18 ℃ environment can be measured placed measured divided by the standard environmental conditions of the film anti-pendulum impact energy is cold, the unit is%.

After testing, the cold sample No. 1 was 85.4%, cold sample No. 2 was 95.2% .1 cold sample number was significantly lower than sample 2, which is a low temperature environment under the 1st sample flexibility have decreased big deterioration, brittleness increased significantly, significantly reduce the impact of packaging performance, tolerability impact, crush, drop a large degree of performance degradation and other destructive, and sample No. 2 in the low temperature flexibility than the change small, still maintain a high impact strength, which is caused by the cold northern regions 1 package of instant noodles sample breakage rate increase and an important reason for the 2nd instant noodle packaging is damaged samples showed no significant change.

Third, the summary

Cold is an important performance indicator soft plastic packaging materials, packaging materials, is the assessment of changes in the physical properties of flexibility at low temperatures, is an indicator of the product packaging should focus on low-temperature environment in circulation. By selecting the appropriate resin material to improve materials packaging materials processing, add the appropriate amount of the plasticizer, the choice of having a good low temperature resistance of packaging materials and other measures can effectively improve the cold bag to prevent bag breakage rate at a low temperature environment increase. Labthink has always been committed to providing professional and welcoming packaging testing equipment testing services to customers worldwide. Learn more information about the testing instruments, Labthink blue light and look forward to the industry enterprises and institutions to promote technology exchange and cooperation.
Source: Labthink