Water-insoluble modified polyvinyl alcohol coating liquor and its preparation process

Abstract

The invention discloses an insoluble modified polyvinyl alcohol coating liquid and preparing method and film through the coating liquid, which comprises the following parts: polyvinyl alcohol, modifier, inorganics, crosslinking agent, catalyst and water. The coating liquid improves levelling, adhering and even property greatly, which increases obstruct property for kinds of gas.

Description

technical field [0001] The invention belongs to a modified polyvinyl alcohol coating solution and a production process thereof. Background technique [0002] In barrier packaging materials, polyvinyl alcohol PVA is a polyhydroxy polymer with a molecular formula of CH 2 -CHOHn, strong water absorption, soluble in water, due to its intermolecular hydrogen bond, high density, good barrier performance, but its high melting point and low decomposition temperature, due to these structural characteristics of PVA, it is difficult for thermoplastic processing . Most of the currently commercially available PVA films are produced by solution casting method, but the disadvantages of casting method are: long production cycle, low production efficiency, film thickness, unstable quality, high cost, strong water absorption of the film, soluble In water, thereby limiting the popularization and application of PVA film, but in the prior art, adopt melamine class to make modifying agent, alth...

AI Technical Summary

Problems solved by technology

[0002] In barrier packaging materials, polyvinyl alcohol PVA is a polyhydroxy polymer with a molecular formula of CH 2 -CHOHn, strong water absorption, soluble in water, due to its intermolecular hydrogen bond, high density, good barrier performance, but its high melting point and low decomposition temperature, due to these structural characteristics of PVA, it is difficult for thermoplastic processing

Most of the currently commercially available PVA films are produced by solution casting method, but the disadvantages of casting method are: long production cycle, low production efficiency, film thickness, unstable quality, high cost, strong water absorption of the film, soluble In water, thereby limiting the popularization and application of PVA film, but in the prior art, adopt melamine class to make modifying agent, although have solved the problem that PVA coating is insoluble in water after film formation, but because in the modification process of PVA Among them, if the amount of plasticizer and modifier is too large, the purity will be reduced, the air permeability will be increased, and the gas barrier performance will be greatly affected by temperature and humidity, and the shelf life of the coating solution is short, which must be within 3-7 hours. Otherwise, it will become jelly-like and cannot be used. Therefore, it can only prepare the coating liquid for its own use, which cannot meet the requirements of being sold as a commodity; and it must be produced with an expensive special coating machine , low output, high energy consumption, and high manufacturing costs restrict its wide application. The base film is polypropylene PP with a thickness of 25 μm, the thickness of the polyvinyl alcohol coating is 10 μm, and its oxygen transmission rate is 3 cm 3 / m 2 ·24h·0.1MPa, the water vapor transmission rate is 4g / m 2 24 hours

Aluminum foil is used as the barrier layer. Because it is opaque, it cannot be applied to occasions that require transparent packaging. Moreover, its price is relatively high, and it cannot meet the social requirements for high-barrier packaging.