Polyvinyl chloride unidirectional heat shrinkable film
DATE：2019/11/7 9:09:55 / READ： / SOURCE：This station
Polyvinyl chloride unidirectional heat shrinkable film
(1) It is a kind of packaging material for decorative bottle sleeves. It is based on PVC transparent sheet, oriented by stretching, has memory in a certain direction, then printed, bonded into a tube, and then placed in glass and metal. On the container of plastic, etc., after being heated and shrunk, it is closely attached to the container to show the shape of the original object. The unprinted PVC unidirectional heat shrinkable film has good transparency, uniform thickness and convenient printing, so that the designer can The consumer's psychological design is more innovative and expresses the packaging of the product content. Because it is one-way contraction, it can also print the corresponding barcode, which is easy to manage and promote sales.
(2) Mechanism Uniform stretching when manufacturing a film, one-way shrinkage during use.
(3) Characteristics and influencing factors of PVC unidirectional heat shrinkable film
Substrate formula:
1) Plasticizer, PVC added plasticizer, the glass transition temperature (Tg) of the substrate decreases, the secondary processing temperature decreases, and the shrinkage initial shrinkage temperature also decreases. The experiment proves that the amount of plasticizer increases. For one copy, the initial shrinkage temperature drops by 1 °C.
2) Impact modifier, using ABS and ACR with good transparency and heat resistance as impact modifier to improve the impact resistance of the substrate. ACR can also improve the surface gloss of the film and enhance the decorative effect.
(4) Process route and process parameters
1) There are two kinds of process routes: longitudinal stretching and transverse stretching: transverse stretching, no free end, easy to control necking phenomenon, but the thickness is difficult to be uniform, the stretching ratio is difficult to change; longitudinal stretching, the film is easy to be uniform, but the neck The phenomenon of shrinkage is not easy to control, and the phenomenon of taking roller close-up stretching is improved.
2) Process parameters: 1 Stretching temperature: generally within the glass transition temperature range. 2 cooling temperature, practice shows that the first cooling roller temperature should be about 20 ° C lower than the stretching temperature, and then gradually reduce the room temperature.
3) The stretching speed and the stretching ratio are determined: the stretching ratio is proportional to the shrinkage ratio of the film, and the theoretical calculation relationship is as follows
K=(1-1/n)×100
K-film heating shrinkage rate (%)
n a draw ratio.
When the draw ratio is less than 2, the shrinkage rate rapidly increases as the draw ratio increases. When the draw ratio is greater than 4, it is of little practical significance to increase the shrinkage ratio by increasing the draw ratio.
(5) Shrinkage temperature used
Generally, the film temperature is required to be 5 to 10 ° C below the glass transition temperature, and the temperature is maintained at 3 to 10 s. t
(6) Product usage
The PVC one-way heat shrinkable decorative bottle cover has been well used by the soda water plant, the beverage factory and the detergent factory. In addition, it is used in mail, battery assembly and plating protective sleeves, and the effect is good.
(1) It is a kind of packaging material for decorative bottle sleeves. It is based on PVC transparent sheet, oriented by stretching, has memory in a certain direction, then printed, bonded into a tube, and then placed in glass and metal. On the container of plastic, etc., after being heated and shrunk, it is closely attached to the container to show the shape of the original object. The unprinted PVC unidirectional heat shrinkable film has good transparency, uniform thickness and convenient printing, so that the designer can The consumer's psychological design is more innovative and expresses the packaging of the product content. Because it is one-way contraction, it can also print the corresponding barcode, which is easy to manage and promote sales.
(2) Mechanism Uniform stretching when manufacturing a film, one-way shrinkage during use.
(3) Characteristics and influencing factors of PVC unidirectional heat shrinkable film
Substrate formula:
1) Plasticizer, PVC added plasticizer, the glass transition temperature (Tg) of the substrate decreases, the secondary processing temperature decreases, and the shrinkage initial shrinkage temperature also decreases. The experiment proves that the amount of plasticizer increases. For one copy, the initial shrinkage temperature drops by 1 °C.
2) Impact modifier, using ABS and ACR with good transparency and heat resistance as impact modifier to improve the impact resistance of the substrate. ACR can also improve the surface gloss of the film and enhance the decorative effect.
(4) Process route and process parameters
1) There are two kinds of process routes: longitudinal stretching and transverse stretching: transverse stretching, no free end, easy to control necking phenomenon, but the thickness is difficult to be uniform, the stretching ratio is difficult to change; longitudinal stretching, the film is easy to be uniform, but the neck The phenomenon of shrinkage is not easy to control, and the phenomenon of taking roller close-up stretching is improved.
2) Process parameters: 1 Stretching temperature: generally within the glass transition temperature range. 2 cooling temperature, practice shows that the first cooling roller temperature should be about 20 ° C lower than the stretching temperature, and then gradually reduce the room temperature.
3) The stretching speed and the stretching ratio are determined: the stretching ratio is proportional to the shrinkage ratio of the film, and the theoretical calculation relationship is as follows
K=(1-1/n)×100
K-film heating shrinkage rate (%)
n a draw ratio.
When the draw ratio is less than 2, the shrinkage rate rapidly increases as the draw ratio increases. When the draw ratio is greater than 4, it is of little practical significance to increase the shrinkage ratio by increasing the draw ratio.
(5) Shrinkage temperature used
Generally, the film temperature is required to be 5 to 10 ° C below the glass transition temperature, and the temperature is maintained at 3 to 10 s. t
(6) Product usage
The PVC one-way heat shrinkable decorative bottle cover has been well used by the soda water plant, the beverage factory and the detergent factory. In addition, it is used in mail, battery assembly and plating protective sleeves, and the effect is good.
Author：admin