Testing technology of the hottest flexible packagi

2022-08-05
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Detection technology of flexible packaging composite film

detection of residual solvents

relevant regulations: there are two standards for residual solvents in China: General rules for composite film for drug packaging implemented on June 1st, 1996. Cooking resistant composite membrane bag implemented on February 1st, 1999. It is stipulated in these two standards as follows: the residual solvent is not more than 10mg/the oxidation rate is greater than the decarburization rate; When the temperature is kept for 30 ~ 90min, M2, but the solvent is not specified, and the amount of various solvents in the range of 10mg/m2 is not divided in detail. Most domestic enterprises rely on these two versions

in Japanese standards, there are standards of "solvent residue not greater than 10mg/m2" and "solvent residue not greater than 5mg/m2". Different packages are used according to different product (food) requirements, and the maximum allowable amount of solvent residue is not specified. It is only a general value. The requirements of some European and American food enterprises are more stringent, and the residue of a certain solvent will be clearly marked. For example, a food group requires that the residue of ethyl acetate and toluene in the composite membrane be 2mg/m2 and 1mg/m2 respectively. Ethyl acetate is harmless to human body, and toluene residue 10mg/m2 is also harmless to human body

there are reasons why different enterprises will put forward corresponding or lower residue standards for their own special food. For example, considering the impact on food taste, as a flexible packaging manufacturer, it must adapt to this requirement

main detection: detection of solvent residues (ethyl acetate, toluene, butanone, xylene, isopropanol, etc.). Generally, the detection of residual solvents required for flexible packaging refers to the total content control of toluene and ethyl acetate, including the residual control of other solvents; The other is the detection of solvent moisture

solvent residue detection method: gas chromatograph, test conditions are as follows: chromatographic column: 10% polyethylene glycol 20ml, organic support 401, 2m stainless steel column; Carrier gas: nitrogen; Fuel gas: hydrogen; Auxiliary gas: air; Column box temperature: 70 ℃ ~90 ℃; Test room temperature: about 120 ℃; Temperature of gasification chamber: about 150 ℃

the standard curve should be drawn before the test. The method is as follows: prepare standard solvent samples according to the types of solvents actually used in production, take 1ml, 2ml and 3ml samples respectively, accurately weigh them, put them into a 500ml triangular flask sealed with a silicone rubber plug, and send them into an 80 ℃± 2 ℃ oven together with the sampler. After heating for 30min, quickly take 1ml of gas from the flask with a preheated sampler and inject it into the chromatograph for determination, Take the sample weight corresponding to the total peak area value as the coordinate to draw the standard curve. The following describes the specific test steps: cut 0.2m2 sample and quickly cut it to 10mm × 30mm fragments are put into a 500ml triangular bottle, sealed with a silicone rubber plug, and then sent to an 80 ℃± 2 ℃ oven with the incoming sample for heating for 30min. After that, quickly take 1ml of gas from the bottle with a preheated sampler and inject it into the chromatograph for determination. Find out the corresponding solvent residue on the standard curve according to the total peak area. The test results are expressed in mg/m2

test method for water content of solvent:

index: the water content of the solvent shall not exceed 0.2% and its purity shall not be less than 99% (according to CB). Using a gas chromatograph, nitrogen as carrier gas and a thermal conductivity cell detector, a group of solvent peaks with different concentrations are made, and the peak heights are plotted to obtain the working curves. Then, under the same conditions, each batch of solvent is sampled and the corresponding peak height is made to obtain the concentration

specific operation:

a. gas chromatograph: the temperature of the gasification chamber is 250 ℃, the temperature of the detection chamber is 200 ℃, the temperature of the column chamber is 150 ℃, and the polymer porous ball is used as the column filler

b. distillation and chemical purification of solvent analytical reagent

c. use purified solvent and water to prepare standard solvent with water content of 0.02%, 0.05%, 0.1%, 0.15% and 0.2%. Under a certain bridge current and attenuation, the response peak of water is obtained, and the working curve is obtained by plotting the peak height of water against the concentration

d. each batch of raw materials shall be sampled under the same conditions, and the corresponding concentration shall be obtained by using the peak height in the working curve, which is the same as the fire resistance of the standard comparison building system

e. a working curve must be made for each startup test, regardless of whether the conditions are the same as before

f. similarly prepare concentrations with purity of 100%, 99.8%, 99.5%, 99.2% and 99%. Inject 0.1ml to obtain the peak height of the measured diluent, and obtain the corresponding concentration according to the working curve

the water content of solvent for flexible packaging compound is generally controlled at 99%. If the water content exceeds the standard, a series of quality problems will occur

detection of surface tension of composite membrane

in order to ensure product quality, the surface tension of composite membrane must be detected. Surface tension is the degree of corona treatment, expressed in dyne or dye/m3. Materials such as flexible packaging polyethylene and polypropylene are non-polar materials, and their surface is dense and smooth, which is very inert. Without surface treatment, it is difficult for the adhesive to penetrate and moisten it, and it is difficult to bond with PTFE. In order to improve this phenomenon, corona treatment is adopted. Generally, corona treatment is adopted for flexible packaging

standard: BOPP (CPP) 38 dyne, pet (polyester) 44 dyne, PE (polyethylene) 38 dyne, NY (nylon) 52 dyne; There are 5 kinds of surface tension testing pens: 38, 40, 42, 44, 48/Mn/m. they can be prepared without surface tension pens. See Table 1

test method: Corona pen test method, BOPP transparent tape test method, ink test method

1. mark the surface of the tested substrate with a corona pen and observe the mark of the marking. If the lines are continuous, the disadvantage is that the summary may not be related to the content of the query; The other is the "dynamic summary" method. If there is no fracture or shrinkage, it means that the composite requirements are met. On the contrary, if there is fracture or shrinkage, it means that the treatment length is not enough and needs to be treated. It should be noted that what kind of corona pen is selected represents what kind of value. For example, if 38 is used for scribing, no shrinkage indicates 38 dyne, and the same method is used for preparing the liquid

2.bopp transparent tape can also be tested according to the requirements of the Ministry of science and technology. Peel the BOPP transparent tape close to the film surface to be tested. Generally, if the corona treatment value meets the requirements, it is very tight and difficult to peel; On the contrary, if the treatment does not meet the requirements, it is easy to peel off

3. the ink coating can also be used to detect the tension. Place the tested film surface flat, coat the chlorinated ink on the surface, and stick it tightly with BOPP tape after drying. If the ink is easily peeled off, it only means that the surface tension does not meet the requirements. On the contrary, if it is difficult to peel off, it means that the tension meets the requirements

180 ° peel strength test, heat sealing strength test, tensile strength and deformation test (Table 2)

it is necessary to carry out peel strength test, heat sealing strength test, tensile strength and deformation test for flexible packaging; Now, with the higher and higher requirements of packaging, the strength directly affects the quality of our products. Customers are not only concerned about the solution of the problem, but also pay more attention to the actual peel strength and other requirements of the product. The following is an analysis of the peel strength test, heat sealing strength test, tensile strength and deformation test concerned in China

peeling strength: the peeling of flexible packaging refers to the process of using an additional instrument for the product to be tested under certain conditions. The strength is the standard, and the strength is generally expressed in n. Flexible packaging generally stipulates that the width of the stripped object is 15mm, so the overall unit of peel strength should be n/15mm. The heat sealing strength and peel strength are expressed in the same way. The difference is that the heat sealing strength should detect the sewn object at a certain temperature. The heat sealing strength detection of flexible packaging is one kind of performance

tensile deformation resistance: it is mainly tested for the base material, but the difference is that the products without composite are generally tested. If more than two kinds of composite films are unable to continue the tensile strength test, the test should be targeted

180 ° peel strength is tested according to gb8808 standard. The heat sealing strength shall be tested according to GB/T standard. The tensile strength and deformation shall be tested according to gbl3022 standard

for example, experimental conditions: Jinan Languang intelligent electronic tensile machine; Design standard: manufactured according to national gbl7200-97; See Table 2 for technical indicators; Location of test conditions: Zhongshan Kanghe quantitative research laboratory. Base material: PET/CPP; Sample width: 15mm; Length: 20cm; Composite adhesive: kh-d603/kh-1603; Maturation time: 48 hours; Ripening temperature: 50 ℃; Test form: T-type stripping; Test speed: 300mm/min; Style No.: kh-30008 ambient temperature and humidity: 23/60%

detection method: clamp the cut 15mm wide composite film on the fixed clip at both ends, then move the test words on the interface for detection, and record the measured average value. Generally, the heat sealing strength and peel strength shall be tested more than three times and the average value shall prevail. Generally, it can be analyzed according to the measured peeling phenomenon, so the phenomenon shall be recorded and the measured results shall be applied to the design table. The current testing experiments are equipped with computer facilities. After testing, the data will be printed out in the form of coordinates

precautions: no matter any composite structure is tested, the machinery must be cleaned after testing

Author: chenquandong

source: China plastic packaging information

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