Preparation of the hottest low-temperature heat se

Preparation of low temperature heat sealable and easy to peel plastic

low temperature heat sealable and easy to peel material is a kind of hot melt sealing material widely used in plastic packaging materials, which is widely used in the sealing materials of cans, boxes, dishes, bottles, etc. The basic requirements for this material are: first, it has good low-temperature heat sealing property, that is, the temperature during heat sealing should be low; Second, good thermal adhesion, good sealing performance of heat seal, reliable heat seal and no leakage; Third, it is easy to tear and peel, as long as a small force can tear and peel; Fourth, it is easy to be coated. The cover material that needs to be sealed can be coated by extrusion coating, roller coating or brush coating. In addition, it should have good heat resistance, oil resistance, acid and alkaline resistance

this low-temperature heat sealing and easy tearing material can be used on the cover materials of aluminum foil, iron foil, paper or plastic, and also on the heat cover of composite material cover materials, such as: fast food noodles cover materials packaged in boxes and barrels, aluminum foil cover materials of milk powder packaged in iron and aluminum barrels, pharmaceutical PTP, jelly packaging, etc. The formula of the low-temperature heat sealable easy tearing material is as follows:

Formula 1:

polyethylene (density 0.923g/cm3, mi=4g/10min) 42.5 parts weight; EVA copolymer (VA content 6%, mi=7g/10min) 42.5 parts by weight; Aliphatic hydrocarbon resin (softening point 115 ℃) 15 parts by weight; Erucic acid amide 0.2 parts by weight

after the above materials are weighed and mixed evenly, they are extruded and granulated at 150 ℃ with a single screw extruder. When used Ф 65 extruder extrudes salivation on the inner PE surface of paper/pe/al foil/pe at the T-shaped die at 250 ℃, and the coating thickness is 30 μ m. The coating speed is 80m/min, which forms plastic, metal or composite and can increase the service life of the experimental machine. The cover material is heat sealed with 0.3MPa pressure for 1s at 130 ℃, 150 ℃ and 160 ℃, and its heat sealing strength is 831g/15mm, 1051g/15mm and 1231g/15mm respectively. This cover material is easy to peel off

formula 2:

pe (density 0.923g/cm3, mi=4g/10min) 65 parts weight; EVA (VA content 6%, mi=7g/10min) 20 parts weight; Tackifier petroleum resin 15 parts by weight; Erucic acid amide 0.2 parts by weight. After the above materials are weighed and mixed evenly, they are granulated with an extruder, and then extruded and coated on the surface of the cover material with a single screw extruder with a T-shaped die, which can be used for the sealing of cans, barrels, bottles, etc

formula 3:

pe (0.925g/cm3 LDPE, mi=4g/10min) 60 parts weight; EVA (VA content 14%w, mi=15g/10min) 25 parts weight; 5 parts weight of aliphatic hydrocarbon resin tackifier with softening point of 115 ℃; Oleic amide 0.1 parts by weight; Stearic acid amide 0.1 parts by weight; Silicon oxide 0.5 parts by weight. After the above materials are weighed and mixed evenly, they are extruded and granulated in a single screw extruder at 150 ℃, and salivated on the hot cover of the cover material by a T-shaped die at 250 ℃, and the heat sealing temperature is between 130 ~ 160 ℃. The cover material that is easy to tear and peel can be obtained. It should be pointed out that with the increase of heat sealing temperature, the heat sealing fastness is improved, and the tearing force is also increased, so that the impact property, mechanical strength and modulus of the material cannot be effectively improved. Therefore, the heat sealing temperature should be controlled within the above temperature to obtain the convenience of tearing

formula 4:

ldpe (specific gravity 0.923g/cm3, mi=4g/10min) 25 parts weight; EVA (VA content 6%w, mi=7g/10min) 45 parts weight; Aliphatic hydrocarbon resin tackifier (softening point closed 1069 down 1.93% 100 ℃) 30 parts by weight; Oleic amide 0.4 parts by weight; Polyethylene glycol 0.1 parts by weight. The above materials are weighed and mixed evenly, extruded and granulated at 150 ℃, extruded and coated at 250 ℃, with a thickness of 30um. They are heat sealed into a cover material at 130 ~ 160 ℃, which can be heat sealed at low temperature and easy to peel off. It can be seen from the above formula that a material that can be heat sealed and peeled at low temperature is composed of LDPE resin and EVA, as well as a tackifying resin and lubricant (amide). The difference between EVA and PE is that EVA has low heat sealing strength and is easy to peel. EVA is a material with good compatibility with LDPE and good heat adhesion. Its melting point and heat sealing temperature are lower than LDPE, and with the increase of VA content, it is different from aluminum foil PVC and other polar materials also have good thermal adhesion and reliable heat sealing, but their heat sealing strength is low and easy to tear off. Tackifying resin can not only improve the adhesion, but also reduce the bonding strength like lubricant, that is, improve the peel resistance

(author/zhouxiangxing)

Guangdong packaging

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