Factors Affecting The Performance Of PVDC Coated Film
DATE：2019/9/26 8:55:11 / READ： / SOURCE：This station
Factors affecting the performance of PVDC coated film
1) Performance of PVDC resin. The composition ratio of vinylidene chloride (VDC) and vinyl chloride (VC) monomers in PVDC copolymers will cause a large change in the barrier properties of PVDC. The VDC content in the copolymer increases, and the barrier property is improved.
2) Formulation of PVDC emulsion. The PVDC emulsion used in the coating operation can be configured with PVDC emulsions of different types (formulations) due to the use of different amounts of PVDC diluent (pure water), processing aids, etc., and the barrier properties and coating processing properties are also different.
The properties of the PVDC emulsion are as follows:
Solid content 43%~55%
Surface wetting tension 37-45mN/m
Density 1.22~1.28g/cm3
Viscosity 5~15cP(1cP=10-Pa·s)
pH 1~3
3) PVDC coating process and operation. In the process of coating PVDC, it is necessary to accurately grasp the main points of the process operation in order to make the coated film have uniform barrier properties.
After corona treatment on the surface of the coated substrate, the surface wetting tension should be 38-42 mN/m; when the surface of the film is pre-coated with solvent-based urethane adhesive or solvent-based PVDC emulsion, the coating amount is
0.5 to 1.5 g/m 2 ; when the main coating PVDC emulsion, the coating amount is 1.5-22 gm 2 .
PVDC coated emulsion should be stored in 5-40 ° C environment, the effective period is not more than half a year; when the emulsion needs to be diluted, pure water should be used; the moisture content of pre-coated PVDC emulsion is ≤ 0.1%; the solid content of PVDC emulsion is generally 40% -55%; the formulated PVDC emulsion should be used after defoaming treatment.
There are three heating sections in the PVDC coating production process. The first heating zone temperature is 55-77 ° C, the solvent in the pre-coating liquid is volatilized; the second heating section uses an infrared heater, the temperature is about 100 ° C, so that the water in the main coating liquid evaporates; the third The temperature of the heating section is 80 to 125 ° C, so that the water in the main coating liquid is completely evaporated, and PVDC is crystallized.
The coated substrate film should be flat, have small thickness deviation, and have high mechanical properties. The tension at the time of coating is large, and the tension at the time of drying is small.
The finished film coated with PVDC should be aged at 24-40 ° C for 24 to 72 hours. The temperature and time of curing can be adjusted according to the coating amount and usage requirements.
1) Performance of PVDC resin. The composition ratio of vinylidene chloride (VDC) and vinyl chloride (VC) monomers in PVDC copolymers will cause a large change in the barrier properties of PVDC. The VDC content in the copolymer increases, and the barrier property is improved.
2) Formulation of PVDC emulsion. The PVDC emulsion used in the coating operation can be configured with PVDC emulsions of different types (formulations) due to the use of different amounts of PVDC diluent (pure water), processing aids, etc., and the barrier properties and coating processing properties are also different.
The properties of the PVDC emulsion are as follows:
Solid content 43%~55%
Surface wetting tension 37-45mN/m
Density 1.22~1.28g/cm3
Viscosity 5~15cP(1cP=10-Pa·s)
pH 1~3
3) PVDC coating process and operation. In the process of coating PVDC, it is necessary to accurately grasp the main points of the process operation in order to make the coated film have uniform barrier properties.
After corona treatment on the surface of the coated substrate, the surface wetting tension should be 38-42 mN/m; when the surface of the film is pre-coated with solvent-based urethane adhesive or solvent-based PVDC emulsion, the coating amount is
0.5 to 1.5 g/m 2 ; when the main coating PVDC emulsion, the coating amount is 1.5-22 gm 2 .
PVDC coated emulsion should be stored in 5-40 ° C environment, the effective period is not more than half a year; when the emulsion needs to be diluted, pure water should be used; the moisture content of pre-coated PVDC emulsion is ≤ 0.1%; the solid content of PVDC emulsion is generally 40% -55%; the formulated PVDC emulsion should be used after defoaming treatment.
There are three heating sections in the PVDC coating production process. The first heating zone temperature is 55-77 ° C, the solvent in the pre-coating liquid is volatilized; the second heating section uses an infrared heater, the temperature is about 100 ° C, so that the water in the main coating liquid evaporates; the third The temperature of the heating section is 80 to 125 ° C, so that the water in the main coating liquid is completely evaporated, and PVDC is crystallized.
The coated substrate film should be flat, have small thickness deviation, and have high mechanical properties. The tension at the time of coating is large, and the tension at the time of drying is small.
The finished film coated with PVDC should be aged at 24-40 ° C for 24 to 72 hours. The temperature and time of curing can be adjusted according to the coating amount and usage requirements.
Author：admin