Introduction of BOPP Tobacco Film Quality Control Index and Testing Technology

BOPP cigarette film has become the preferred material for cigarette packaging due to its excellent moisture resistance and optical properties, wide heat sealing range and high heat-sealing strength, reasonable heat shrinkage, good stiffness and other advantages, while measuring the performance of BOPP tobacco film. The important measure of good or bad is the detection index of smoke film. To facilitate the control of the enterprise better quality indicators BOPP film and understand smoke detection, Labthink blue light associated with the needs of the production, for each index and detection method for detecting smoke BOPP film is introduced, in order to be able to cigarettes and cigarette BOPP The production company is helpful.

1 , BOPP smoke vapor barrier

Cigarette packaging requires smoke films to have high water vapor barrier properties to prevent mildew problems due to moisture. At present, the importance of the detection index in cigarette factories or cigarette packs is not enough, but the detection of moisture in cigarette packs has become more standard in foreign countries. In this article , Labthink 's TSY-T1H moisture permeability tester is introduced as an example. The water vapor transmission rate of the material is measured according to the standards of GB1037 , ASTM E96 and ISO 2528. The smaller the water vapor transmission rate, the better. , But to achieve higher water vapor barrier performance, you need to increase costs. The industry generally takes less than the value="10" hasspace="False" negative="False" numbertype="1" tcsc="0" w:st=" On"> 10g /m2.day (but empirically less than value="5" hasspace="False" negative="False" numbertype="1" tcsc="0" w:st="on"> 5g / M2.day is more ideal).

2 , BOPP smoke film thickness

The thickness of BOPP smoke film is the basic index of the laboratory test film performance. The uneven thickness will not only affect the tensile strength and barrier properties of the smoke film, but also affect the subsequent processing of the smoke film . The thicker the smoke film, the better the performance of the machine and the higher the stiffness. The package out of the cigarette package has a good visual aesthetic appearance, but the cost is high. In order to seek the balance of the control, you need to use a high-precision thickness gauge. Labthink 's CHY-C2 thickness gauge is a laboratory-specific thickness gauge with an accuracy of 0.1um . When performing thickness tests, it is important to note that in addition to measuring vertical and horizontal thickness, the deviation must be controlled, generally within 3% , and the edge thickness of the film needs to be detected. This is extremely important.

3 , BOPP smoke film tensile strength and elongation, elastic modulus

The cigarette pack requires the BOPP film to have a high tensile strength, which will reduce the “ break ” phenomenon of the film during the packaging process as much as possible . The general requirement is greater than 140N/mm2 in the longitudinal direction and greater than 220N/mm2 in the transverse direction . The elongation at break test is used for the analysis of the ease of cutting of the film. The cigarette pack industry differs from other industries in that it is not so good that the elongation at break is better. The cigarette pack industry generally requires the control to be less than 200% in the longitudinal direction and 80% or less in the horizontal direction . This makes it easier to cut off the machine and increase the production process. Patency. In the general industry, these two indicators are mainly tested. However, with the more specific requirements for the stiffening of the smoke film and the ease of cutting due to high-speed production, there are currently requirements for the detection of elastic moduli. Labthink 's XLW ( PC ) intelligent electronic tensile testing machine is a professional tensile testing machine for film testing, and it also has a fixed elastic modulus detection function. The elastic modulus of the smoke film is not easy to be too small. Otherwise, the film is soft and has poor rigidity, which also leads to poor cutting and running, and may even result in bulking and film clogging. In general, the smoke film requires an elastic modulus of more than 2000N/mm2 . However, when testing the elastic modulus, we must pay attention to the conditions of the test. If the test temperature is different, the test data will also have large changes (the higher the temperature, the lower the elastic modulus). Therefore, the test conditions must be specified during the experiment.

4 , BOPP film seal strength

The cigarette industry requires that the BOPP film must have a high heat seal strength and a wide heat sealing range, thereby increasing the packaging speed and operational flexibility. Of course, if the heat-sealing temperature of the BOPP film is high, the wrinkle phenomenon resulting from the high shrinkage of the film can be navigated. Therefore, according to the actual situation, should choose the appropriate heat sealing temperature, to avoid the heat seal is not strong, fly package, wrinkle and so on.

The heat sealing of the BOPP smoke film adopts the hot-press sealing method, that is, the sealing is performed under the three conditions of the set heat sealing temperature, the heat sealing pressure, and the heat sealing time. The heat seal strength test is to detect the minimum force required to separate the heat seals after heat sealing. The HST-H3 heat seal tester and the XLW ( PC ) type intelligent electronic tensile tester are widely used in the industry. They are used in combination. The heat seal strength of the smoke film is generally 2.0N/value="15" hasspace=" False" negative="False" numbertype="1" tcsc="0" w:st="on">15mm or more. Nowadays, with the improvement of the production efficiency of the cigarette packer, the low-temperature heat-sealing film on the market is receiving more and more courtesy. The heat-sealing strength of such a low-temperature heat-sealing film is generally greater than 1.5N/value="15" hasspace="False" Negative="False" numbertype="1" tcsc="0" w:st="on">15mm can.

5 , BOPP smoke film friction coefficient

The slippery performance of BOPP cigarette film is an important indicator in the comprehensive index, and it is the testing demand that comes with high-speed packaging. In the cigarette packaging process and the entire production process, there are four cases of friction coefficient testing: 1 coefficient of friction between the outside of the film and the mechanical metal surface or conveyor belt 2 inside and outside the film , 3 inside and outside the film 4 outside the film and the carton . The coefficient of friction between the outside of the film and the mechanical metal surface should be relatively low to facilitate the transport of cigarette packets on the production line and to increase the speed of production of the package. The coefficient of friction between the inside and the inside of the film should be slightly higher than the coefficient of friction between the outside of the film and the metal, in order to facilitate the precise fixing of the position of the film and the cigarette paper, and to improve the heat sealing quality and the packaging effect. The coefficient of friction between the film and the carton is low, so that the cigarette package can be smoothly loaded. In the general industry, the test is conducted according to the GB 10006 standard. The test speed is value="100" hasspace="False" negative="False" numbertype="1" tcsc="0" w:st="on"> 100mm / Min (US standard value="150" hasspace="False" negative="False" numbertype="1" tcsc="0" w:st="on"> 150mm /min ).

Labthink 's MXD-02 friction coefficient instrument is highly favored by companies in the industry for its excellent satisfaction with various standards such as national standards, American standards, and international standards. Because there are many references for the friction coefficient of cigarette packs (such as for metal plates, cigarette packs, medial to medial, and lateral to medial), the data range is relatively large, and the friction coefficient generally ranges from 0.2 to 0.6 .

6 , BOPP film shrinkage rate detection

The thermal shrinkage of BOPP film is mainly used to evaluate the thermal stability of BOPP film under different conditions or factors. For the case of hard box tobacco, since the cigarette box has a good strength support effect, a smoke film with a high shrinkage rate can be used, so that a smooth and beautiful visual effect can be achieved, so the heat shrinkage rate of the BOPP film is generally required. It reaches 8% to 12% . However, soft cigarette cases need to prevent the deformation of cigarette packs due to excessive shrinkage. In the industry, the shrinkage rate is generally controlled at 3% to 7% . For BOPP film heat shrinkage smoke detection reference current industry substantially GB / T 13519 or U.S. standard ASTM D2732 to detect, in this order of Labthink RSY-R2 thermal tester described as an example, in the sample Longitudinal and horizontal respectively draw an axis of symmetry as the mark, and marked vertical and horizontal, the sample is placed flat between the two frames, then quickly immersed in 120±value="2" hasspace="False" negative="False" numbertype=" 1" tcsc="0" w:st="on"> Freely shrinks in a constant temperature medium at 2 °C , removes it after 20 s , immerses it in a spare room temperature bath, cools it for 5 s , removes the sample, and stands still at 30 °C . Measure the vertical and horizontal symmetry axis dimensions in min . Accurate to value="1" hasspace="True" negative="False" numbertype="1" tcsc="0" w:st="on"> 1 mm and record the measurement data. At present, companies have adopted the test with value="120" hasspace="False" negative="False" numbertype="1" tcsc="0" w:st="on"> 120 °C and heating for one or five minutes. If the conditions are different, the test results will be different.

7 , BOPP smoke film scratch resistance (wear resistance)

Nowadays, the cigarette industry has increasingly strict requirements on film scratch resistance. The bad scratch resistance of cigarette packs will greatly affect the appearance. The detection of the abrasion resistance mainly comes from two aspects: First, the film during the high-speed packaging production process The rapid contact and friction between the surface and the machine will scratch the surface of the product. Second, during the transportation of the product, the surface of the film rubs against the packaging box or other surface to generate scratches. However, there are no national or industry standards in the industry that can be used for reference. Labthink Languang combines the current industry to carry out inspections to summarize the situation, basically refer to the GB7706 standard in the printing ink wear resistance detection method, you can use MCJvalue = "1" hasspace = "False" negative = "True" number type = "1" tcsc="0" w:st="on">The -01A friction tester performs the test. Use a width of value="50" hasspace="False" negative="False" numbertype="1" tcsc="0" w:st="on"> 50mm , value="80" hasspace="False" negative= "False" number type="1" tcsc="0" w:st="on">80g / m2 clean offset paper is fixed on the load weight of the friction tester, cut the cigarette film to a certain size and installed on the friction table. , Set the number of frictions (different executions by each company), start the test, and check the scratches after the test.

8 , BOPP smoke film optical properties

Higher transparency and higher gloss are the eternal requirements of the market for BOPP film to match cigarette packs to show better appearance. The two main indicators that reflect the optical properties of the film are haze and gloss. Haze is also known as transparency, gloss is the surface brightness. The lower the haze value, the higher the transparency of the film, and thus the cigarette brand logo, etc., are clearer and brighter. The higher the gloss, the more beautiful and bright the cigarette pack is, and the visual effect is better. A low haze, high gloss film will make the cigarette look more upscale, thereby increasing the consumer's desire to buy.

In short, there are many BOPP cigarette smoke detection items, which must be performed in accordance with the standards. If there is no standard, the test conditions must be unified so that the data can be comparable. Jinan Languang Electromechanical Technology Co., Ltd. ( 0531-85068566 ) is willing to carry out more exchanges and discussions on the quality control and inspection of BOPP smoke film and industry.