CN112297560A - Antibacterial two-way stretching polylactic acid film capable of being directly heat-sealed and preparation method thereof - Google Patents
Antibacterial two-way stretching polylactic acid film capable of being directly heat-sealed and preparation method thereof Download PDFInfo
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/001—Combinations of extrusion moulding with other shaping operations
- B29C48/0018—Combinations of extrusion moulding with other shaping operations combined with shaping by orienting, stretching or shrinking, e.g. film blowing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/022—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the choice of material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/07—Flat, e.g. panels
- B29C48/08—Flat, e.g. panels flexible, e.g. films
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/16—Articles comprising two or more components, e.g. co-extruded layers
- B29C48/18—Articles comprising two or more components, e.g. co-extruded layers the components being layers
- B29C48/21—Articles comprising two or more components, e.g. co-extruded layers the components being layers the layers being joined at their surfaces
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
- B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
- B29C55/10—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial
- B29C55/12—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial
- B29C55/14—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial successively
- B29C55/143—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial successively firstly parallel to the direction of feed and then transversely thereto
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D65/00—Wrappers or flexible covers; Packaging materials of special type or form
- B65D65/38—Packaging materials of special type or form
- B65D65/40—Applications of laminates for particular packaging purposes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W90/00—Enabling technologies or technologies with a potential or indirect contribution to greenhouse gas [GHG] emissions mitigation
- Y02W90/10—Bio-packaging, e.g. packing containers made from renewable resources or bio-plastics
Abstract
The invention discloses an antibacterial two-way stretching polylactic acid film capable of being directly heat-sealed, which sequentially consists of an upper surface layer, a core layer and a lower surface layer; the raw material of the upper surface layer is heat-sealing polylactic acid slices, and the heat-sealing polylactic acid slices comprise 80-90 wt% of crystalline polylactic acid and 10-20 wt% of non-crystalline polylactic acid; the raw material of the core layer is a crystalline polylactic acid slice; the raw materials of the lower surface layer comprise 80-90 wt% of crystalline polylactic acid slices and 10-20 wt% of inorganic antibacterial master batch, and the inorganic antibacterial master batch comprises graphene-loaded silver and crystalline polylactic acid. The polylactic acid film is prepared by adopting reasonable raw material proportion and biaxial stretching, can be directly subjected to heat sealing, has good antibacterial performance, and can prolong the storage time of food when being used for food packaging.
Description
Technical Field
The invention relates to the technical field of polylactic acid films, in particular to an antibacterial directly heat-sealable biaxially oriented polylactic acid film and a preparation method thereof.
Background
Along with the continuous development of plastic packaging, the plastic packaging product gradually occupies the main body of human life, but along with the development, the plastic packaging product also brings the problem of environmental protection, and the market demands for safety and environmental protection are gradually improved.
Polylactic acid belongs to an important biodegradable environment-friendly high polymer material in aliphatic polyester, has a source different from the traditional material, and can be prepared by fermenting grain crops such as corn, sugarcane and the like; has good machining performance, can be processed in various modes, and has good market prospect. The polylactic acid film has good application potential in the field of packaging materials, and has high requirements on the antibacterial property, the heat sealability and other properties of the polylactic acid film for food packaging materials.
Disclosure of Invention
Based on the technical problems in the background art, the invention provides an antibacterial directly heat-sealable bidirectional stretched polylactic acid film and a preparation method thereof.
The invention provides an antibacterial two-way stretching polylactic acid film capable of being directly heat-sealed, which is characterized by sequentially consisting of an upper surface layer, a core layer and a lower surface layer;
the raw material of the upper surface layer is a heat-sealing polylactic acid slice, and the heat-sealing polylactic acid slice comprises 80-90 wt% of crystalline polylactic acid and 10-20 wt% of amorphous polylactic acid;
the raw material of the core layer is a crystalline polylactic acid slice;
the raw materials of the lower surface layer comprise 80-90 wt% of crystallized polylactic acid slices and 10-20 wt% of inorganic antibacterial master batch, and the inorganic antibacterial master batch comprises graphene loaded silver and crystallized polylactic acid.
Preferably, the graphene-loaded silver accounts for 12-16 wt% of the total mass of the inorganic antibacterial master batch.
Preferably, the mass of the silver accounts for 30-60% of the total mass of the graphene-supported silver.
Preferably, the melt indexes of the crystalline polylactic acid and the non-crystalline polylactic acid are both 2-10g/10min at 190 ℃ and 2.16 kg.
Preferably, the upper surface layer accounts for 10-20% of the total thickness of the film, the core layer accounts for 60-80% of the total thickness of the film, and the lower surface layer accounts for 10-20% of the total thickness of the film.
The preparation method of the antibacterial directly heat-sealable biaxially oriented polylactic acid film comprises the following steps:
s1, drying the raw materials of the core layer, adding the dried raw materials into a main extruder for heating and melting, filtering the dried raw materials through a filter to obtain core layer melt, adding the raw materials of the upper surface layer and the lower surface layer into two auxiliary extruders for heating and melting, vacuumizing to obtain the upper surface layer melt and the lower surface layer melt, and enabling the core layer melt, the upper surface layer melt and the lower surface layer melt to enter a three-layer co-extrusion die head for converging and extruding to obtain the membrane;
s2, attaching the film sheet obtained in the step S1 to a chill roll by electrostatic adsorption, and cooling to form a cast sheet;
s3, preheating the cast sheet obtained in the step S2, longitudinally stretching, cooling and shaping to obtain a sheet;
and S4, preheating the sheet, transversely stretching, and then carrying out shaping and crystallization treatment.
Preferably, in step S1, the drying conditions of the raw material for the core layer are as follows: drying at 60-70 deg.C for 4-5 h; in the step S1, the filter is a disc filter, and the moisture content of the core layer melt after filtration is less than or equal to 50 ppm; in the step S1, the confluent extrusion conditions are: the temperature is 170 ℃ and 230 ℃, and the screw rotating speed of the double-screw extruder is 20-100 rpm.
Preferably, in the step S2, the cooling temperature is 25 to 35 ℃.
Preferably, in the step S3, the preheating temperature is 60-70 ℃, the longitudinal stretching temperature is 100-110 ℃, the longitudinal stretching magnification is 2-3 times, and the cooling and setting temperature is 20-40 ℃.
Preferably, in the step S4, the preheating temperature is 80-100 ℃, the transverse stretching temperature is 110-120 ℃, the transverse stretching magnification is 3-5, and the setting crystallization treatment temperature is 160-180 ℃.
The invention has the following beneficial effects:
the antibacterial two-way stretching polylactic acid film capable of being directly heat-sealed comprises an upper surface layer, a core layer and a lower surface layer, wherein the upper surface layer is made of heat-sealing polylactic acid slices, the core layer is made of crystalline polylactic acid slices, the heat-sealing polylactic acid slices comprise 80-90 wt% of crystalline polylactic acid and 10-20 wt% of non-crystalline polylactic acid, the lower surface layer is made of 80-90 wt% of crystalline polylactic acid slices and 10-20 wt% of inorganic antibacterial master batch, and the inorganic antibacterial master batch comprises graphene-loaded silver and crystalline polylactic acid. The polylactic acid film is prepared by adopting reasonable raw material proportion and biaxial stretching, can be directly subjected to heat sealing, has good antibacterial performance, and can prolong the storage time of food when being used for food packaging.
Detailed Description
The technical solution of the present invention will be described in detail below with reference to specific examples.
In the following examples, the graphene-supported silver is commercially available under the model of XF071, manufactured by Nanjing Xiancheng nanomaterial science and technology Co., Ltd, wherein the mass of the silver accounts for 50% of the total mass of the graphene-supported silver.
Example 1
An antibacterial two-way stretched polylactic acid film capable of being directly heat-sealed consists of an upper surface layer, a core layer and a lower surface layer in sequence; the raw material of the upper surface layer is heat-sealing polylactic acid slices, and the heat-sealing polylactic acid slices comprise 80 wt% of crystalline polylactic acid and 20 wt% of non-crystalline polylactic acid; the raw material of the core layer is a crystalline polylactic acid slice; the raw materials of the lower surface layer comprise 90 wt% of crystallized polylactic acid slices and 10 wt% of inorganic antibacterial master batch, the inorganic antibacterial master batch comprises graphene-loaded silver and crystallized polylactic acid, and the graphene-loaded silver accounts for 14 wt% of the total mass of the inorganic antibacterial master batch.
The melt indexes of the crystalline polylactic acid and the non-crystalline polylactic acid are both 2-10g/10min at 190 ℃ and 2.16 kg.
The upper surface layer accounts for 15% of the total thickness of the film, the core layer accounts for 70% of the total thickness of the film, and the lower surface layer accounts for 15% of the total thickness of the film.
The preparation method of the antibacterial directly heat-sealable biaxially oriented polylactic acid film comprises the following steps:
s1, drying the raw materials of the core layer at 70 ℃ for 5h, adding the raw materials into a main extruder for heating and melting, filtering the mixture through a disc filter to obtain a core layer melt, wherein the moisture content of the filtered core layer melt is less than or equal to 50ppm, adding the raw materials of the upper surface layer and the lower surface layer into two auxiliary extruders for heating and melting, performing vacuum pumping treatment to obtain the upper surface layer melt and the lower surface layer melt, feeding the core layer melt, the upper surface layer melt and the lower surface layer melt into a three-layer co-extrusion die head, and performing converging extrusion under the conditions that the temperature is 210 ℃ and the screw rotation speed of a double-screw extruder is 80rpm to obtain a membrane;
s2, attaching the membrane sheet obtained in the step S1 to a chill roll by electrostatic adsorption, and cooling at 30 ℃ to form a cast sheet;
s3, preheating the cast sheet obtained in the step S2 at 60-70 ℃, longitudinally stretching at 100-110 ℃, wherein the longitudinal stretching magnification is 3 times, and then cooling and shaping at 20-40 ℃ to obtain a sheet;
s4, preheating the sheet at 80-100 ℃, transversely stretching at 110-120 ℃, wherein the transverse stretching ratio is 4 times, then carrying out setting crystallization treatment at 160-180 ℃, carrying out air cooling treatment on the obtained film, then entering a traction system, flattening, trimming, thickness measuring and corona treatment, and then rolling to obtain a mother roll.
Example 2
An antibacterial two-way stretched polylactic acid film capable of being directly heat-sealed consists of an upper surface layer, a core layer and a lower surface layer in sequence; the raw material of the upper surface layer is heat-sealing polylactic acid slices, and the heat-sealing polylactic acid slices comprise 85 wt% of crystalline polylactic acid and 15 wt% of non-crystalline polylactic acid; the raw material of the core layer is a crystalline polylactic acid slice; the raw materials of the lower surface layer comprise 85 wt% of crystallized polylactic acid slices and 15 wt% of inorganic antibacterial master batch, the inorganic antibacterial master batch comprises graphene-loaded silver and crystallized polylactic acid, and the graphene-loaded silver accounts for 12 wt% of the total mass of the inorganic antibacterial master batch.
The melt indexes of the crystalline polylactic acid and the non-crystalline polylactic acid are both 2-10g/10min at 190 ℃ and 2.16 kg.
The upper surface layer accounts for 15% of the total thickness of the film, the core layer accounts for 70% of the total thickness of the film, and the lower surface layer accounts for 15% of the total thickness of the film.
The preparation method of the antibacterial directly heat-sealable biaxially oriented polylactic acid film comprises the following steps:
s1, drying the raw materials of the core layer at 70 ℃ for 5h, adding the raw materials into a main extruder for heating and melting, filtering the mixture through a disc filter to obtain a core layer melt, wherein the moisture content of the filtered core layer melt is less than or equal to 50ppm, adding the raw materials of the upper surface layer and the lower surface layer into two auxiliary extruders for heating and melting, performing vacuum pumping treatment to obtain the upper surface layer melt and the lower surface layer melt, feeding the core layer melt, the upper surface layer melt and the lower surface layer melt into a three-layer co-extrusion die head, and performing converging extrusion under the conditions that the temperature is 210 ℃ and the screw rotation speed of a double-screw extruder is 80rpm to obtain a membrane;
s2, attaching the membrane sheet obtained in the step S1 to a chill roll by electrostatic adsorption, and cooling at 25-35 ℃ to form a cast sheet;
s3, preheating the cast sheet obtained in the step S2 at 60-70 ℃, longitudinally stretching at 100-110 ℃, wherein the longitudinal stretching magnification is 3 times, and then cooling and shaping at 20-40 ℃ to obtain a sheet;
s4, preheating the sheet at 80-100 ℃, transversely stretching at 110-120 ℃, wherein the transverse stretching ratio is 4 times, then carrying out setting crystallization treatment at 160-180 ℃, carrying out air cooling treatment on the obtained film, then entering a traction system, flattening, trimming, thickness measuring and corona treatment, and then rolling to obtain a mother roll.
Example 3
An antibacterial two-way stretched polylactic acid film capable of being directly heat-sealed consists of an upper surface layer, a core layer and a lower surface layer in sequence; the raw material of the upper surface layer is heat-sealing polylactic acid slices, and the heat-sealing polylactic acid slices comprise 90 wt% of crystalline polylactic acid and 10 wt% of non-crystalline polylactic acid; the raw material of the core layer is a crystalline polylactic acid slice; the raw materials of the lower surface layer comprise 80 wt% of crystallized polylactic acid slices and 20 wt% of inorganic antibacterial master batch, the inorganic antibacterial master batch comprises graphene-loaded silver and crystallized polylactic acid, and the graphene-loaded silver accounts for 16 wt% of the total mass of the inorganic antibacterial master batch.
The melt indexes of the crystalline polylactic acid and the non-crystalline polylactic acid are both 2-10g/10min at 190 ℃ and 2.16 kg.
The upper surface layer accounts for 15% of the total thickness of the film, the core layer accounts for 70% of the total thickness of the film, and the lower surface layer accounts for 15% of the total thickness of the film.
The preparation method of the antibacterial directly heat-sealable biaxially oriented polylactic acid film comprises the following steps:
s1, drying the raw materials of the core layer at 70 ℃ for 5h, adding the raw materials into a main extruder for heating and melting, filtering the mixture through a disc filter to obtain a core layer melt, wherein the moisture content of the filtered core layer melt is less than or equal to 50ppm, adding the raw materials of the upper surface layer and the lower surface layer into two auxiliary extruders for heating and melting, performing vacuum pumping treatment to obtain the upper surface layer melt and the lower surface layer melt, feeding the core layer melt, the upper surface layer melt and the lower surface layer melt into a three-layer co-extrusion die head, and performing converging extrusion under the conditions that the temperature is 210 ℃ and the screw rotation speed of a double-screw extruder is 80rpm to obtain a membrane;
s2, attaching the membrane sheet obtained in the step S1 to a chill roll by electrostatic adsorption, and cooling at 30 ℃ to form a cast sheet;
s3, preheating the cast sheet obtained in the step S2 at 60-70 ℃, longitudinally stretching at 100-110 ℃, wherein the longitudinal stretching magnification is 3 times, and then cooling and shaping at 20-40 ℃ to obtain a sheet;
s4, preheating the sheet at 80-100 ℃, transversely stretching at 120 ℃ of 110-.
Comparative example 1
A two-way stretching polylactic acid film consists of an upper surface layer, a core layer and a lower surface layer in sequence; the raw materials of the upper surface layer, the core layer and the lower surface layer are all crystalline polylactic acid slices, and the melt index of the crystalline polylactic acid is 2-10g/10min at 190 ℃ under the condition of 2.16 kg.
The upper surface layer accounts for 15% of the total thickness of the film, the core layer accounts for 70% of the total thickness of the film, and the lower surface layer accounts for 15% of the total thickness of the film.
The preparation method of the two-way stretching polylactic acid film comprises the following steps:
s1, drying the raw materials of the core layer at 70 ℃ for 5h, adding the raw materials into a main extruder for heating and melting, filtering the mixture through a disc filter to obtain a core layer melt, wherein the moisture content of the filtered core layer melt is less than or equal to 50ppm, adding the raw materials of the upper surface layer and the lower surface layer into two auxiliary extruders for heating and melting, performing vacuum pumping treatment to obtain the upper surface layer melt and the lower surface layer melt, feeding the core layer melt, the upper surface layer melt and the lower surface layer melt into a three-layer co-extrusion die head, and performing converging extrusion under the conditions that the temperature is 210 ℃ and the screw rotation speed of a double-screw extruder is 80rpm to obtain a membrane;
s2, attaching the membrane sheet obtained in the step S1 to a chill roll by electrostatic adsorption, and cooling at 30 ℃ to form a cast sheet;
s3, preheating the cast sheet obtained in the step S2 at 60-70 ℃, longitudinally stretching at 100-110 ℃, wherein the longitudinal stretching magnification is 3 times, and then cooling and shaping at 20-40 ℃ to obtain a sheet;
s4, preheating the sheet at 80-100 ℃, transversely stretching at 110-120 ℃, wherein the transverse stretching ratio is 4 times, then carrying out setting crystallization treatment at 160-180 ℃, carrying out air cooling treatment on the obtained film, then entering a traction system, flattening, trimming, thickness measuring and corona treatment, and then rolling to obtain a mother roll.
The products obtained in examples 1 to 3 and comparative example 1 were subjected to the performance test, and the results are shown in table 1:
table 1 product Performance test results
The detection results in table 1 show that the antibacterial directly heat-sealable biaxially oriented polylactic acid film prepared by the invention is obviously improved in light transmittance and antibacterial property, and has good heat-sealing property.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.
Claims (9)
1. An antibacterial two-way stretched polylactic acid film capable of being directly heat-sealed is characterized by sequentially consisting of an upper surface layer, a core layer and a lower surface layer;
the raw material of the upper surface layer is a heat-sealing polylactic acid slice, and the heat-sealing polylactic acid slice comprises 80-90 wt% of crystalline polylactic acid and 10-20 wt% of amorphous polylactic acid;
the raw material of the core layer is a crystalline polylactic acid slice;
the raw materials of the lower surface layer comprise 80-90 wt% of crystallized polylactic acid slices and 10-20 wt% of inorganic antibacterial master batch, and the inorganic antibacterial master batch comprises graphene loaded silver and crystallized polylactic acid.
2. The antibacterial directly heat-sealable biaxially oriented polylactic acid film according to claim 1, wherein the graphene-loaded silver accounts for 12-16 wt% of the total mass of the inorganic antibacterial master batch; preferably, the mass of the silver accounts for 30-60% of the total mass of the graphene-supported silver.
3. The antibacterial directly heat-sealable biaxially stretched polylactic acid film according to claim 1 or 2, wherein the melt index of each of the crystalline polylactic acid and the amorphous polylactic acid is 2 to 10g/10min at 190 ℃ under 2.16 kg.
4. The antibacterial directly heat-sealable biaxially oriented polylactic acid film and the process for producing the same according to any one of claims 1 to 3, wherein the upper surface layer accounts for 10 to 20% of the total thickness of the film, the core layer accounts for 60 to 80% of the total thickness of the film, and the lower surface layer accounts for 10 to 20% of the total thickness of the film.
5. A method for preparing the antibacterial directly heat-sealable biaxially oriented polylactic acid film according to any one of claims 1 to 4, comprising the steps of:
s1, drying the raw materials of the core layer, adding the dried raw materials into a main extruder for heating and melting, filtering the dried raw materials through a filter to obtain core layer melt, adding the raw materials of the upper surface layer and the lower surface layer into two auxiliary extruders for heating and melting, vacuumizing to obtain the upper surface layer melt and the lower surface layer melt, and enabling the core layer melt, the upper surface layer melt and the lower surface layer melt to enter a three-layer co-extrusion die head for converging and extruding to obtain the membrane;
s2, attaching the film sheet obtained in the step S1 to a chill roll by electrostatic adsorption, and cooling to form a cast sheet;
s3, preheating the cast sheet obtained in the step S2, longitudinally stretching, cooling and shaping to obtain a sheet;
and S4, preheating the sheet, transversely stretching, and then carrying out shaping and crystallization treatment.
6. The method for preparing an antibacterial two-way stretch polylactic acid film capable of being directly heat sealed according to claim 5, wherein in step S1, the drying conditions of the raw materials of the core layer are as follows: drying at 60-70 deg.C for 4-5 h; in the step S1, the filter is a disc filter, and the moisture content of the core layer melt after filtration is less than or equal to 50 ppm; in the step S1, the confluent extrusion conditions are: the temperature is 170 ℃ and 230 ℃, and the screw rotating speed of the double-screw extruder is 20-100 rpm.
7. The method for preparing an antibacterial heat-sealable biaxially stretched polylactic acid film according to claim 5 or 6, wherein the cooling temperature in the step S2 is 25 to 35 ℃.
8. The method for preparing an antibacterial heat-sealable biaxially stretched polylactic acid film according to any one of claims 5 to 7, wherein in the step S3, the preheating temperature is 60 to 70 ℃, the longitudinal stretching temperature is 100 ℃ and 110 ℃, the longitudinal stretching magnification is 2 to 3 times, and the cooling setting temperature is 20 to 40 ℃.
9. The method as claimed in any one of claims 5 to 8, wherein the preheating temperature is 80-100 ℃, the transverse stretching temperature is 110-120 ℃, the transverse stretching magnification is 3-5, and the setting crystallization treatment temperature is 160-180 ℃ in step S4.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113621146A (en) * | 2021-07-22 | 2021-11-09 | 厦门长塑实业有限公司 | Antifogging antibacterial mildew-proof polylactic acid master batch, film thereof and preparation method |
| CN113895126A (en) * | 2021-10-11 | 2022-01-07 | 安徽金田高新材料股份有限公司 | High-shrinkage biaxially-oriented polylactic acid film and preparation method thereof |
| CN114083862A (en) * | 2021-11-05 | 2022-02-25 | 厦门长塑实业有限公司 | High-interface-binding-force bidirectional-stretching polylactic acid composite film and preparation method and application thereof |
| CN114771069A (en) * | 2022-03-30 | 2022-07-22 | 安徽国风新材料股份有限公司 | Antifogging type bidirectional stretching polylactic acid film and preparation method thereof |
| CN115403907A (en) * | 2022-09-29 | 2022-11-29 | 桂林格莱斯科技有限公司 | Single-layer heat-sealable bidirectional stretched polylactic acid film and preparation method thereof |
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| CN113621146A (en) * | 2021-07-22 | 2021-11-09 | 厦门长塑实业有限公司 | Antifogging antibacterial mildew-proof polylactic acid master batch, film thereof and preparation method |
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| CN114083862B (en) * | 2021-11-05 | 2023-02-28 | 厦门长塑实业有限公司 | High-interface-binding-force bidirectional-stretching polylactic acid composite film and preparation method and application thereof |
| CN114771069A (en) * | 2022-03-30 | 2022-07-22 | 安徽国风新材料股份有限公司 | Antifogging type bidirectional stretching polylactic acid film and preparation method thereof |
| CN115403907A (en) * | 2022-09-29 | 2022-11-29 | 桂林格莱斯科技有限公司 | Single-layer heat-sealable bidirectional stretched polylactic acid film and preparation method thereof |
| CN115403907B (en) * | 2022-09-29 | 2023-10-20 | 桂林格莱斯科技有限公司 | Single-layer heat-sealable biaxially oriented polylactic acid film and preparation method thereof |
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