EVA films, which stand out for their excellent elasticity, are often produced by extrusion blow molding. The properties of this film are closely related to the content of vinyl acetate (VA). Njengoba okuqukethwe kwe-V kukhuphuka, ifilimu liyathuthuka ngokuya ngokuqina kwe-elasticity, ukumelana nokuqina kwengcindezelo, ukumelana okuphansi kokushisa, kanye nokwelula ukushisa. When the VA content reaches 15%~20%, its performance is even comparable to that of flexible PVC film. Conversely, when the VA content is lower, the film performance is closer to that of LDPE film. Generally, the content of VA in EVA film is controlled in the range of 10%~20%.
EVA films are known for their transparency, softness, and self-adhesiveness to the comfortable feel. Its excellent stress crack resistance and high elasticity make the elongation as high as 59%~80%, making it an ideal spiral wound film. Ensimini yokupakisha, kusetshenziswa kabanzi eqoqweni kanye nokusonga kwamabhokisi nezimpahla ezifuthwe, kanye nokugoqwa kwe-pallets. Ngasikhathi sinye, ifilimu ye-EVA nayo ilungele ukukhiqizwa kwezikhwama zokupakisha izinto ezisindayo ezifana nomanyolo kanye nezinto zokwakha amakhemikhali. In addition, it has excellent low-temperature heat sealing and inclusion sealing, and is often used as a heat sealing layer for composite films.
The production methods of PVA films include solution casting and extrusion blow molding. Ngenxa yokushisa okuphezulu okuncibilikayo kwe-PVA kanye nokusondela kwayo ekushiseni okukhohlisayo, ukukhishwa okuqondile okunciphile kunzima, ngakho-ke ukuhlukaniswa kwamanzi kuvame ukusetshenziswa ukunciphisa izinga lokushisa. In this way, the film needs to be dried and dehydrated after molding to obtain a practical PVA film. In the field of packaging, the industry prefers to use the cast method to produce PVA films.
PVA films can be divided into water-resistant films and water-soluble films. Amafilimu alwa namanzi enziwe nge-PVA ene-degree ye-polymerization engaphezu kwe-1000 futhi ehlelwe ngokuphelele, ngenkathi amafilimu ancibilikisiwe amanzi enziwa nge-PVA etholwe ngokwengxenye ene-polymerization ephansi. In packaging applications, we mainly use water-resistant PVA films.
Ifilimu ye-PVA, evelele ukucaca kwayo okuhle kakhulu futhi igxile kakhulu, ayithambekele kangako ekuqongeleleni kukagesi okuyisitayela kanye nokumunca uthuli, kepha futhi inokusebenza okuhle kokuphrinta. In the dry state, it exhibits excellent airtightness and fragrance retention, as well as excellent oil resistance. In addition, PVA films have good mechanical strength, toughness, and resistance to stress cracking, and can be heat-sealed. However, due to its high moisture permeability and strong water absorption, the dimensional stability needs to be improved. Ukuze uxazulule le nkinga, i-polyvinylidene chloride coating, ie, k coating, imvamisa isetshenziselwa ukuthuthukisa ukuqina komoya, ukugcinwa kwamakha kanye nokuphindwa komswakama kanye nokuphikiswa komswakama. This specially treated PVA film is ideal for food packaging.
Ifilimu le-PVA livame ukusetshenziswa njengengqimba ye-barrier yamafilimu ahlanganisiwe, futhi isetshenziswa kabanzi ekuphaketheni kokudla okusheshayo, imikhiqizo yenyama, imikhiqizo yekhilimu nokunye ukudla. At the same time, its single film is also widely used in the packaging of textiles and clothing. Ngaphezu kwalokho, amafilimu we-PVA ancibilikayo abuye abe nokusebenza okuhle kakhulu ku-metering kanye nokupakishwa kwemikhiqizo yamakhemikhali anjenge-disinfectants, ama-detergents, i-bleach, amadayi, ama-pesticides wezinto ezibulala izinambuzane.
Ngenjwayelo,
Isikhathi sePosi: Mar-18-2025