Thermoshrinkable polyester film and preparation method thereof

Abstract

The invention discloses a thermoshrinkable polyester film and a preparation method thereof. The preparation method comprises steps as follows: various polyester raw materials subjected to dust removal respectively enter storage bins, are respectively metered by an agravic weigher according to the proportion, simultaneously enter an inlet of a double screw extruder, are subjected to melt extrusion by a sandwich layer double screw extruder and two surface layer double screw extruders, and form a casting piece through a three-layer co-extrusion die head; the casting piece is respectively subjected to longitudinal stretching and lateral stretching, wherein the longitudinal stretching comprises a preheating zone, a stretching zone, a thermal setting zone and a cooling zone, and the thermal setting zone of the lateral stretching is more than 15m long; and the casting piece is subjected to traction rolling to obtain the thermoshrinkable polyester film. By adopting the proportioning mode of directly feeding after accurate metering by people, the instantaneous addition error range of various materials is at most 1%; and the material is biaxially stretched, so that the produced film has the advantages of greatly higher density, strength and uniformity, lower longitudinal shrinkage and lateral low-temperature shrinkage, and especially higher ductility and thermoshrinkable uniformity.

Description

technical field

[0001] The invention relates to the technical field of heat-shrinkable polyester films, and also relates to a preparation method of heat-shrinkable polyester films. Background technique

[0002] Heat shrinkable film is widely used due to its ability to shrink when heated at a predetermined temperature, such as: labeling bottles, packaging batteries, packaging containers and other products. Commonly used heat shrinkable films are made of polyvinyl chloride (PVC), polystyrene (OPS) or polyester (PET).

[0003] Since heat shrinkable films made of PVC and OPS are relatively poor in terms of shrinkage and printing and dyeing properties, especially when incinerated, they will emit toxic pollutants, which do not conform to the development direction of green industry, and have been gradually banned. PET heat shrinkable film has attracted people's attention because of its excellent heat resistance, chemical resistance, shrinkage and printing and dyeing properties. It...

Examples

Embodiment 1

[0035] (1) Ingredients: The intrinsic viscosity is 0.8dl / g, 20% IPA, 80% TPA and 20% NPG, 10% CHDM, 70 %EG copolymerized PET copolyester and PET polyester are mixed according to the content ratio of 70wt% and 30wt% as the core layer raw material. PET copolyester and PET polyester containing 3000ppm anti-blocking agent silica with a particle size of 1.2μm are mixed according to the content ratio of 70wt% and 30wt% as the surface layer raw material. After the various polyester raw materials are dedusted, they enter their respective silos, and then pass through a buffer silo for buffering, and then are measured by the loss-in-weight scale according to the ratio of raw materials, and then enter the entrance of the twin-screw extruder through an accumulator at the same time. , The error range of the added amount of the material-to-feed ratio is ≤1%.

[0036] (2) Extrusion casting: Under the conditions of vacuum degree of 5mbar and extrusion temperature of 265°C, the homogeneously ...

Embodiment 2

[0040] (1) Ingredients: With an intrinsic viscosity of 0.85dl / g, 20% IPA, 80% TPA and 20% NPG, 10% CHDM, 70% EG copolymerized PET copolyester and PET polyester are mixed according to the content ratio of 75wt% and 25wt% as the core material. Mix PET copolyester with PET polyester containing 3300ppm anti-blocking agent calcium carbonate with a particle size of 2.8μm at a content ratio of 75wt% and 25wt%, as the surface layer raw material, and send it to the cyclone separator by vacuum suction. Dust removal, after dust removal, enters the respective silos respectively, and then after being buffered by a hose, after being measured by the weight loss scale according to the ratio of raw materials, at the same time, it enters the entrance of the twin-screw extruder through a funnel-shaped collector, and the materials The error range of the added amount of the feed ratio is ≤1%.

[0041] (2) Extruded cast sheet: Under the condition of vacuum degree of 4mbar and extrusion temperature...

Embodiment 3

[0045] (1) Ingredients: The intrinsic viscosity is 0.75dl / g, 20% IPA, 80% TPA and 20% NPG, 10% CHDM, 70 %EG copolymerized PET copolyester and PET polyester are mixed according to the content ratio of 80wt% and 20wt% as the core material. Mix PET copolyester and PET polyester containing 3000ppm anti-blocking agent silica with a particle size of 0.9μm at a content ratio of 80wt% and 20wt% as the surface layer raw materials, and send various raw materials by compressed air feeding To the cyclone separator for dust removal, after dust removal, they enter their respective silos, and then after being buffered by a buffer device, they are measured by their respective loss-in-weight scales according to the ratio of raw materials, and at the same time enter the twin-screw through a funnel-shaped collector. At the entrance of the extruder, the error range of the added amount of the material-to-feed ratio is ≤1%.

[0046] (2) Extrusion casting: Under the conditions of vacuum degree of 5...

technical field

[0001] The invention relates to the technical field of heat-shrinkable polyester films, and also relates to a preparation method of heat-shrinkable polyester films. Background technique

[0002] Heat shrinkable film is widely used due to its ability to shrink when heated at a predetermined temperature, such as: labeling bottles, packaging batteries, packaging containers and other products. Commonly used heat shrinkable films are made of polyvinyl chloride (PVC), polystyrene (OPS) or polyester (PET).

[0003] Since heat shrinkable films made of PVC and OPS are relatively poor in terms of shrinkage and printing and dyeing properties, especially when incinerated, they will emit toxic pollutants, which do not conform to the development direction of green industry, and have been gradually banned. PET heat shrinkable film has attracted people's attention because of its excellent heat resistance, chemical resistance, shrinkage and printing and dyeing properties. It...

Examples

Embodiment 1

[0035] (1) Ingredients: The intrinsic viscosity is 0.8dl / g, 20% IPA, 80% TPA and 20% NPG, 10% CHDM, 70 %EG copolymerized PET copolyester and PET polyester are mixed according to the content ratio of 70wt% and 30wt% as the core layer raw material. PET copolyester and PET polyester containing 3000ppm anti-blocking agent silica with a particle size of 1.2μm are mixed according to the content ratio of 70wt% and 30wt% as the surface layer raw material. After the various polyester raw materials are dedusted, they enter their respective silos, and then pass through a buffer silo for buffering, and then are measured by the loss-in-weight scale according to the ratio of raw materials, and then enter the entrance of the twin-screw extruder through an accumulator at the same time. , The error range of the added amount of the material-to-feed ratio is ≤1%.

[0036] (2) Extrusion casting: Under the conditions of vacuum degree of 5mbar and extrusion temperature of 265°C, the homogeneously ...

Embodiment 2

[0040] (1) Ingredients: With an intrinsic viscosity of 0.85dl / g, 20% IPA, 80% TPA and 20% NPG, 10% CHDM, 70% EG copolymerized PET copolyester and PET polyester are mixed according to the content ratio of 75wt% and 25wt% as the core material. Mix PET copolyester with PET polyester containing 3300ppm anti-blocking agent calcium carbonate with a particle size of 2.8μm at a content ratio of 75wt% and 25wt%, as the surface layer raw material, and send it to the cyclone separator by vacuum suction. Dust removal, after dust removal, enters the respective silos respectively, and then after being buffered by a hose, after being measured by the weight loss scale according to the ratio of raw materials, at the same time, it enters the entrance of the twin-screw extruder through a funnel-shaped collector, and the materials The error range of the added amount of the feed ratio is ≤1%.

[0041] (2) Extruded cast sheet: Under the condition of vacuum degree of 4mbar and extrusion temperature...

Embodiment 3

[0045] (1) Ingredients: The intrinsic viscosity is 0.75dl / g, 20% IPA, 80% TPA and 20% NPG, 10% CHDM, 70 %EG copolymerized PET copolyester and PET polyester are mixed according to the content ratio of 80wt% and 20wt% as the core material. Mix PET copolyester and PET polyester containing 3000ppm anti-blocking agent silica with a particle size of 0.9μm at a content ratio of 80wt% and 20wt% as the surface layer raw materials, and send various raw materials by compressed air feeding To the cyclone separator for dust removal, after dust removal, they enter their respective silos, and then after being buffered by a buffer device, they are measured by their respective loss-in-weight scales according to the ratio of raw materials, and at the same time enter the twin-screw through a funnel-shaped collector. At the entrance of the extruder, the error range of the added amount of the material-to-feed ratio is ≤1%.

[0046] (2) Extrusion casting: Under the conditions of vacuum degree of 5...

Images