| BOPP testing is very important for BOPP quality | | | | more popular, which requires the heat seal |
| control. BOPP(Biaxially Oriented Polypropylene) | | | | strength above 1.5N/15mm. |
| cigarette film, with is excellent moisture barrier | | | | E. BOPP Cigarette Film Coefficient of Friction |
| property, optical performances, heat seal | | | | Testing |
| property as well as high heat seal strength, | | | | The smoothness of BOPP cigarette film is one |
| reasonable shrinkage rate and good stiffness, is | | | | important index for BOPP films with is the testing |
| the first choice for cigarette film. The testing | | | | requirements coming along with the high speed |
| items of BOPP are the judgment for BOOP film | | | | packing. |
| performance. In order to better control the quality | | | | There are four kinds of situations that need |
| of BOPP cigarette film, Labthink, integrates the | | | | coefficient of friction testing, namely, the |
| testing demand and introduces the relevant BOPP | | | | coefficient of friction of the film and the metal |
| cigarette film testing methods and items, so as to | | | | side of the machine or the transfer belt; the inside |
| bring useful helps for the cigarette companies. | | | | side between films; the film inner side and the |
| A. Moisture Barrier Property Testing of BOPP | | | | cigarette outer package; and the outer film side |
| Cigarette Film | | | | and the outer package. Of these four coefficients |
| High moisture barrier property performance is a | | | | of friction, the first should be low so as to better |
| must for cigarette package so as to avoid | | | | transfer the cigarette package and improve |
| deterioration caused by moisture. At present, this | | | | packing speed. |
| factor is not fully noticed by the cigarette | | | | The inside coefficient of friction should be a bit |
| manufacturers. Labthink PARAM TSY-T1H is | | | | higher than that of the outer film and the machine |
| developed according to ASTM E96, ISO 2528 and | | | | metal side for precise location of film and |
| other standards to test moisture transmission | | | | cigarette package so as to improve heat seal |
| rate for materials. The lower WVTR the better. | | | | quality and packing effects. The coefficient of film |
| But, higher barrier property means more costs. | | | | and outer paper box should be low for smooth |
| Therefore, the common data is less than 10g | | | | insertion of cigarette packages. The testing speed |
| m2.day or 5g/m2.day. | | | | is 100mm/min, or 150mm/min in US Standard. |
| B. Thickness of BOPP | | | | Labthink PARAM MXD-02 Coefficient of Friction |
| Thickness of BOPP cigarette film is the basic film | | | | Tester complies with many standards including US |
| performance index. Uneven thickness would | | | | standards and international standards, and gets |
| influence the tensile strength and permeability as | | | | wide applications. Since the reference for cigarette |
| well as the following procedures. Thicker cigarette | | | | film coefficient of friction varies, e.g., metal panel, |
| film would have better stiffness with better visual | | | | cigarette box, inner and outer sides of films, etc., |
| performance. But, the cost would also be great. In | | | | the coefficient of friction is normally between |
| order to find the balanced solution, high precision | | | | 0.2-0.6. |
| thickness tester is needed. Labthink PARAM | | | | F. The Heat Shrinkage Testing for BOPP Cigarette |
| CHY-C2 is the lab thickness tester with the | | | | Film |
| precision up to 0.1um. When testing thickness in | | | | BOPP film heat shrinkage is mainly used for the |
| different directions, deviation must be controlled | | | | evaluation of heat stability under different |
| within 3% usually. Meanwhile, the edge thickness | | | | conditions or different factors. For rigid cigarette |
| of BOPP film has to be measured. | | | | package, such rigid package has good support |
| C. BOPP Cigarette Film Tensile Strength, Elongation | | | | effect, around which high shrinkage film can be |
| and Elastic Modulus | | | | applied so as to achieve even and beautiful visual |
| Cigarette package requires high tensile strength of | | | | effects. Therefore, rigid package requires the |
| BOPP films, which can greatly reduce the | | | | heat shrinkage of BOPP cigarette film to be up to |
| breakage during packaging process. Generally, | | | | 8% to 12%. |
| 140N/mm2 vertically and 200N/mm2 crosswise | | | | But, deformation cause by high shrinkage rate is a |
| are required. Elongation rate is for analysis of | | | | problem for ordinary flexible cigarette package. |
| incision easiness of films. Cigarette packaging | | | | Generally, the shrinkage rate is controlled within |
| industry is different from other industries. Higher | | | | 3%-7%. For heat shrinkage testing of BOPP |
| elongation rate is not better. Max. limitations of | | | | cigarette film, ASTM D 2732, or GB/T 13519 is |
| 200% vertically and 80% crosswise can | | | | applied. Take Labthink PARAM RSY-R2 Film Free |
| guarantee easy incision and assembling | | | | Shrink Tester as an example; mark the vertical |
| smoothness. Other industries require those two | | | | and crosswise lines on the specimen with clear |
| indexes. But cigarette package requires more | | | | indication of direction. Put the specimen in |
| detailed requirements on incision easiness during | | | | between the frame, and immediately emerge into |
| high speed production. Therefore, Elastic Modulus | | | | 120±2C constant temperature medium for 20 |
| testing is also put forward. Labthink PARAM | | | | seconds. Then, emerge the specimen into the |
| XLW(PC) Auto Tensile Tester is the professional | | | | prepared normal temperature bath for 5 seconds, |
| tester for film and its tensile strength with Elastic | | | | and take it out. Lay horizontally and measure the |
| Modulus testing. Low Elastic Modulus would lead to | | | | vertical and crosswise size within 30 minutes. The |
| worse stiffness, unsuccessful production | | | | measurement should be with accuracy up to 1 |
| procedure and inferior incision easiness as well as | | | | mm. At present, some companies heats 1 minute, |
| package breakage and film obstruction. | | | | 5 minutes or other conditions under 120C with |
| Commonly, Elastic Modulus is required to be above | | | | different testing results. |
| 2000N/mm2 for cigarette film. However, when | | | | G. BOPP Cigarette Film Abrasion Resistance |
| testing Elastic Modulus, testing conditions and | | | | Testing |
| temperature must be emphasized. Otherwise, the | | | | With stricter requirements for abrasion resistance, |
| results will fluctuate greatly. Therefore, testing | | | | inferior abrasion resistance performance would |
| condition must be stated. | | | | greatly influence the beauty of the cigarette |
| D. The Heat Seal Strength of BOPP Cigarette Film | | | | package. The testing of abrasion resistance is to |
| BOPP is required to have high heat seal strength | | | | avoid scratch on the surface of the product |
| and wider heat seal scope by the cigarette | | | | caused by the contact of film surface and the |
| industry, so as to improve packing speed and | | | | machine; and to avoid wounds caused by film and |
| proper operation. If the heat seal temperature is | | | | outer package. Labthink PARAM MCJ-01A Rub |
| higher, it would lead to wrinkle because of | | | | Tester can be applied for the test. Take a piece |
| increased BOPP film shrinkage. Therefore, proper | | | | of clean offset paper of 50mm width and 80g |
| heat seal temperature should be chosen so as to | | | | m2 onto the rub tester. Cut a piece of BOPP |
| avoid unstable heat seal, wrinkle and other | | | | cigarette of certain size and put on the rub |
| phenomena. The heat seal style of BOPP | | | | platform. Set the rub times and start to see the |
| cigarette film is heat-pressure seal, that is, to heat | | | | abrasion. |
| seal at certain heat seal temperature, pressure | | | | Above all, there are many BOPP cigarette film |
| and period. The heat seal testing is to test the | | | | testing items. When testing, relevant standards |
| minimum heat seal separating force after heat | | | | must be applied; or unified testing conditions for |
| sealing. It is widely applied in the cigarette industry | | | | data comparison. Labthink, is willing to have |
| that Labthink PARAM HST-H3 Heat Seal Tester | | | | further dialogues on BOPP film and its quality with |
| and PARAM XLW (PC) Auto Tensile Tester are | | | | professionals of the industry. |
| used together. The heat seal strength of cigarette | | | | Labthink Instruments Co., Ltd. |
| is normally required to be above 2.0N/15mm. | | | | No. 144 Wuyingshan Road, Jinan 250031, China |
| Now, with the development of cigarette packing | | | | Tracy Bao info@labthink. |
| machine, low temperature heat seal film becomes | | | | |