CN112406228A - Ultrathin plastic film, preparation method of ultrathin plastic film and express bag - Google Patents

Ultrathin plastic film, preparation method of ultrathin plastic film and express bag Download PDF

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Publication number
CN112406228A
CN112406228A CN201910778380.4A CN201910778380A CN112406228A CN 112406228 A CN112406228 A CN 112406228A CN 201910778380 A CN201910778380 A CN 201910778380A CN 112406228 A CN112406228 A CN 112406228A
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China
Prior art keywords
surface layer
plastic film
percent
density polyethylene
raw materials
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CN201910778380.4A
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Chinese (zh)
Inventor
武睿泽
王梦琪
王海龙
张皓佳
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Shenzhen SF Taisen Holding Group Co Ltd
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Shunqihe Shenzhen Technology Co Ltd
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Priority to CN201910778380.4A priority Critical patent/CN112406228A/en
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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
    • 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
    • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
    • 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
    • B65D31/00—Bags or like containers made of paper and having structural provision for thickness of contents
    • B65D31/02—Bags or like containers made of paper and having structural provision for thickness of contents with laminated walls
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
    • C08J2323/04—Homopolymers or copolymers of ethene
    • C08J2323/06—Polyethene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
    • C08J2323/04—Homopolymers or copolymers of ethene
    • C08J2323/08—Copolymers of ethene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2423/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2423/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
    • C08J2423/04—Homopolymers or copolymers of ethene
    • C08J2423/06—Polyethene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2423/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2423/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
    • C08J2423/04—Homopolymers or copolymers of ethene
    • C08J2423/08—Copolymers of ethene

Abstract

The invention belongs to the technical field of plastic products, and particularly relates to an ultrathin plastic film, a preparation method of the ultrathin plastic film and an express bag, wherein the ultrathin plastic film comprises an inner surface layer, a middle layer and an outer surface layer which are sequentially combined, and the inner surface layer comprises the following raw materials in percentage by weight: 75-85% of linear low-density polyethylene and 12-27% of metallocene ethylene-hexene copolymer; the raw materials of the middle layer comprise the following substances in percentage by weight: 14 to 33 percent of high-density polyethylene and 56 to 87 percent of linear low-density polyethylene or metallocene polyethylene; the outer surface layer comprises the following raw materials in percentage by weight: 15 to 37 percent of bimodal polyethylene and 46 to 86 percent of linear low-density polyethylene. Through repeated tests on the raw material composition and weight ratio of the inner surface layer, the middle layer and the outer surface layer, the thickness of the ultrathin plastic film is successfully reduced to about 0.04mm, and meanwhile, the mechanical property of the ultrathin plastic film is ensured.

Description

Ultrathin plastic film, preparation method of ultrathin plastic film and express bag
Technical Field
The invention belongs to the technical field of plastic products, and particularly relates to an ultrathin plastic film, a preparation method of the ultrathin plastic film and an express bag.
Background
With the vigorous development of the e-commerce industry, express services enter a high-speed development stage, and express bags are important carriers for packaging and protecting express items in express logistics. The express bag needs to be considered in the aspects of meeting mechanical property indexes and strictly controlling cost in the manufacturing process.
In the prior art, in order to meet mechanical property indexes, the thickness of a plastic film for manufacturing the express bag is generally in an interval of 0.05 mm-0.06 mm, and if the thickness is lower than 0.05mm, the mechanical property of the plastic film is reduced, so that the express bag is easy to tear under the action of external forces such as impact, tearing and the like, and further, the express bag is scratched and damaged.
Disclosure of Invention
The invention aims to provide an ultrathin plastic film, a preparation method of the ultrathin plastic film and an express bag, and aims to solve the technical problem that the mechanical property of the plastic film for manufacturing the express bag is reduced when the thickness of the plastic film is less than 0.05mm in the prior art.
In order to achieve the purpose, the invention adopts the technical scheme that: an ultrathin plastic film comprises an inner surface layer, a middle layer and an outer surface layer which are sequentially combined, wherein the ultrathin plastic film comprises the following components in percentage by weight of 100% of the raw materials of the inner surface layer:
75 to 85 percent of linear low-density polyethylene
12 to 27 percent of metallocene ethylene-hexene copolymer;
the intermediate layer comprises the following components in percentage by weight of 100 percent of raw materials:
14 to 33 percent of high-density polyethylene
54% -87% of linear low-density polyethylene or metallocene polyethylene;
the outer surface layer comprises the following components in percentage by weight of 100 percent of raw materials:
15 to 37 percent of bimodal polyethylene
46 to 86 percent of linear low density polyethylene.
Further, the raw material of the inner surface layer also comprises black master batch, wherein the black master batch accounts for 2-5 wt% of the inner surface layer.
Furthermore, the raw materials of the middle layer and the outer surface layer both comprise white master batches, and in the middle layer, the white master batches account for 12-20% of the middle layer by weight;
in the outer surface layer, the white master batch accounts for 14-25 wt% of the outer surface layer.
Furthermore, the thickness ratio of the inner surface layer, the middle layer and the outer surface layer is (2-4): 3-5): 2-4.
Further, the thickness ratio of the inner surface layer, the middle layer and the outer surface layer is 3:4: 3.
Further, the thickness ratio of the inner surface layer, the middle layer and the outer surface layer is 2:2: 1.
Further, the linear low density polyethylene has a weight average molecular weight of 11 to 14 ten thousand g/mol.
Further, the weight average molecular weight of the metallocene polyethylene is 23-31 ten thousand g/mol.
Further, the weight average molecular weight of the metallocene ethylene-hexene copolymer is 9-16 ten thousand g/mol.
The embodiment of the invention has the following beneficial effects: according to the ultrathin plastic film provided by the embodiment of the invention, the inner surface layer, the middle layer and the outer surface layer are arranged, so that the three layers of the inner surface layer, the middle layer and the outer surface layer are combined to ensure the integral strength of the ultrathin plastic film at first. Through repeated tests on the raw material composition and weight ratio of the inner surface layer, the middle layer and the outer surface layer, the thickness of the ultrathin plastic film consisting of the inner surface layer, the middle layer and the outer surface layer is finally successfully reduced to 0.04mm (the positive deviation is 0.005mm, and the negative deviation is 0.002mm), namely 0.038 mm-0.045 mm. Meanwhile, the mechanical property of the ultrathin plastic film is ensured, so that the ultrathin plastic film has low manufacturing cost, thin thickness and good mechanical property, and the requirement on the mechanical property can be met when the thickness of the ultrathin plastic film is less than 0.05mm when the ultrathin plastic film is used for manufacturing express bags.
The invention adopts another technical scheme that: a preparation method of an ultrathin plastic film comprises the following steps:
s1: providing the following raw materials in parts by weight for the inner surface layer:
75 to 85 percent of linear low-density polyethylene
12-27% of metallocene ethylene-hexene copolymer
Uniformly mixing the raw materials of the inner surface layer and blow-molding the raw materials of the inner surface layer into an inner surface layer film;
s2: providing the following raw materials of the middle layer in parts by weight:
14 to 33 percent of high-density polyethylene
56 to 87 percent of linear low-density polyethylene or metallocene polyethylene
Uniformly mixing the raw materials of the middle layer and blow-molding to form a middle layer film;
s3: providing the following raw materials of the outer surface layer in parts by weight:
15 to 37 percent of bimodal polyethylene
46 to 86 percent of linear low-density polyethylene
Uniformly mixing the raw materials of the outer surface layer and blow-molding to form an outer surface layer film;
s4: co-extruding the inner surface layer film, the intermediate layer film and the outer surface layer film to form the ultrathin plastic film.
According to the preparation method of the ultrathin plastic film provided by the embodiment of the invention, through multiple tests, reasonable raw material compositions and weight proportions of the inner surface layer, the middle layer and the outer surface layer are finally determined, the thickness of the ultrathin plastic film prepared by the method is successfully reduced to 0.038-0.045 mm, the mechanical property of the ultrathin plastic film is ensured not to be reduced, and the bonding firmness of the inner surface layer film, the middle layer film and the outer surface layer film is ensured by co-extrusion molding.
The invention adopts another technical scheme that: an express delivery bag is prepared from the ultrathin plastic film.
Furthermore, the thickness of the express bag is 0.038 mm-0.045 mm.
The express bag provided by the embodiment of the invention is made of the ultrathin plastic film, the thickness of the ultrathin plastic film is reduced to about 0.04mm, and the mechanical property can be maintained at the original level. Therefore, the thickness of the express bag can be effectively reduced, and the mechanical property of the express bag can be kept unchanged. Therefore, the manufacturing cost of the express bag is obviously reduced while the mechanical property of the express bag is effectively ensured.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
Fig. 1 is a schematic structural diagram of an ultra-thin plastic film provided by an embodiment of the present invention;
fig. 2 is a process flow chart of a method for manufacturing an ultra-thin plastic film according to an embodiment of the present invention.
Wherein, in the figures, the respective reference numerals:
10-ultrathin plastic film 11-inner surface layer 12-middle layer
13-outer surface layer.
Detailed Description
The embodiments described below with reference to fig. 1-2 are exemplary and intended to be illustrative of the invention and should not be construed as limiting the invention. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The mass of each component mentioned in the description of the embodiment of the present invention may not only refer to the specific content of each component, but also represent the proportional relationship of the mass between each component, therefore, it is within the scope of the disclosure of the description of the embodiment of the present invention to scale up or down the content of each component of the composition according to the description of the embodiment of the present invention. Specifically, the mass described in the description of the embodiment of the present invention may be a unit of weight known in the medical field such as μ g, mg, g, kg, etc.
In the description of the present invention, it is to be understood that the terms "first", "second" and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
As shown in fig. 1, an ultra-thin plastic film 10 according to an embodiment of the present invention includes an inner skin layer 11, an intermediate layer 12, and an outer skin layer 13, which are sequentially combined. The inner surface layer 11, the middle layer 12 and the outer surface layer 13 can be formed by co-extrusion. When the ultrathin plastic film 10 is applied to manufacturing express bags, the inner surface layer 11 of the ultrathin plastic film 10 corresponds to the inner layer of the express bag, and the outer surface layer 13 corresponds to the outer layer of the express bag. Specifically, the inner surface layer 11 comprises the following components by weight percent of 100 percent of the raw materials:
75 to 85 percent of linear low-density polyethylene
12 to 27 percent of metallocene ethylene-hexene copolymer;
further, the raw material of the intermediate layer 12 includes the following substances by weight percentage:
14 to 33 percent of high-density polyethylene
56 to 87 percent of linear low-density polyethylene or metallocene polyethylene;
further, the raw materials of the outer surface layer 13 comprise the following substances in percentage by weight:
15 to 37 percent of bimodal polyethylene
46 to 86 percent of linear low density polyethylene.
The ultra-thin plastic film 10 provided by the embodiment of the present invention is further described below: according to the ultrathin plastic film 10 provided by the embodiment of the invention, the inner surface layer 11, the middle layer 12 and the outer surface layer 13 are arranged, so that the three layers of the inner surface layer 11, the middle layer 12 and the outer surface layer 13 are combined to ensure the integral strength of the ultrathin plastic film 10 firstly. Through repeated tests on the raw material composition and weight ratio of the inner surface layer 11, the intermediate layer 12 and the outer surface layer 13, the thickness of the ultrathin plastic film 10 consisting of the inner surface layer 11, the intermediate layer 12 and the outer surface layer 13 is finally successfully reduced to 0.04mm (the positive deviation is 0.005mm, and the negative deviation is 0.002mm), namely 0.038 mm-0.045 mm. Meanwhile, the mechanical property of the ultrathin plastic film 10 is ensured, so that the ultrathin plastic film 10 has low manufacturing cost, thin thickness and good mechanical property, and the requirement of the mechanical property can be met when the thickness of the ultrathin plastic film 10 is less than 0.05mm when the ultrathin plastic film is used for manufacturing express bags.
In another embodiment of the present invention, the raw material of the inner surface layer 11 further includes black masterbatch, and the black masterbatch accounts for 2% to 5% of the weight of the inner surface layer 11. Specifically, through making the raw materials of inner skin layer 11 include black master batch, like this when ultrathin plastic film 10 is applied to making the express delivery bag, its inner skin layer 11 is the black, has realized thermal-insulated shading on the one hand, has effectively controlled the temperature in the express delivery bag, avoids the express delivery piece because of the interior high temperature impaired, and on the other hand has also effectively guaranteed the privacy nature of express delivery piece.
In another embodiment of the present invention, the raw materials of the middle layer 12 and the outer surface layer 13 both include white master batches, and in the middle layer 12, the white master batches account for 12% to 20% by weight of the middle layer 12; in the outer surface layer 13, the white master batch accounts for 14-25% of the outer surface layer 13 by weight. Specifically, through making the raw materials of intermediate level 12 and outer surface 13 all include white master batch, intermediate level 12 and outer surface 13's colour can be white or light color system such as milk white like this, just so show whole pleasing to the eye degree and the cleanliness factor that have promoted the express delivery bag.
In another embodiment of the present invention, the thickness ratio of the inner surface layer 11, the middle layer 12 and the outer surface layer 13 is (2-4): 3-5): 2-4. Specifically, the thickness ratio of inner skin layer 11, intermediate layer 12, and outer skin layer 13 is 3:4:3 or 2:2: 1. Therefore, the thickness of the middle layer 12 can be effectively ensured, and the raw material of the middle layer 12 comprises a large amount of linear low density polyethylene or metallocene polyethylene, and the linear low density polyethylene or metallocene polyethylene has excellent tensile strength, impact resistance, puncture resistance and heat sealing performance, so that the mechanical property of the middle layer 12 is ensured, and the middle layer 12 can provide main mechanical property guarantee for the whole ultrathin plastic film 10. By setting the thickness ratio of the inner skin layer 11, the intermediate layer 12 and the outer skin layer 13 to 2:2:1, the thickness of the outer skin layer 13 is further increased, and the overall mechanical properties of the ultra-thin plastic film 10 are also further improved.
Further, in the raw material of the intermediate layer 12, it is preferable to replace the linear low density polyethylene with metallocene polyethylene, and the mechanical property index of the metallocene polyethylene is approximately the same as that of the linear low density polyethylene, but the use cost is slightly lower than that of the linear low density polyethylene, so that the metallocene polyethylene can reduce the overall manufacturing cost of the ultra-thin plastic film 10. In the raw material of the outer skin layer 13, the linear low density polyethylene cannot be replaced by metallocene polyethylene. Since the linear low density polyethylene has better smoothness than the metallocene polyethylene, it can improve the overall smoothness of the outer skin layer 13, thereby ensuring that the outer skin layer 13 has better touch feeling.
In another embodiment of the present invention, the linear low density polyethylene has a weight average molecular weight of 11 to 14 ten thousand g/mol. Specifically, the linear low density polyethylene may have a weight average molecular weight of 11 ten thousand g/mol, 11.5 ten thousand g/mol, 12 ten thousand g/mol, 12.5 ten thousand g/mol, 13 ten thousand g/mol, 13.5 ten thousand g/mol, 14 ten thousand g/mol or 14.5 ten thousand g/mol. By limiting the weight average molecular weight of the linear low density polyethylene to 11-14 kg/mol, it is ensured that the outer skin layer 13, the intermediate layer 12 and the inner skin layer 11 comprising the linear low density polyethylene have good machinability.
In another embodiment of the invention, the linear low density polyethylene is brand XP 8784. Specifically, by selecting XP8784 linear low density polyethylene, the XP8784 linear low density polyethylene has excellent film toughness and sealing performance, so that the ultrathin plastic film 10 has good processing performance, the sealing performance is improved, and the sealing performance of the express bag made of the ultrathin plastic film 10 is further ensured.
In another embodiment of the present invention, the metallocene polyethylene has a weight average molecular weight of 23 to 31 ten thousand g/mol. Specifically, the metallocene polyethylene may have a weight average molecular weight of 23 ten thousand g/mol, 23.5 ten thousand g/mol, 24 ten thousand g/mol, 24.5 ten thousand g/mol, 25 ten thousand g/mol, 25.5 ten thousand g/mol, 26 ten thousand g/mol, 26.5 ten thousand g/mol, 27 ten thousand g/mol, 27.5 ten thousand g/mol, 28 ten thousand g/mol, 28.5 ten thousand g/mol, 29 ten thousand g/mol, 29.5 ten thousand g/mol, 30 ten thousand g/mol, 30.5 ten thousand g/mol or 31 ten thousand g/mol, and the weight average molecular weight of the metallocene polyethylene is limited to 23 ten thousand g/mol to 31 ten thousand g/mol, so that when the linear low density polyethylene is replaced by the metallocene polyethylene as the intermediate layer 12, the metallocene polyethylene can further improve the mechanical processability and mechanical property parameters of the intermediate layer 12, and further optimize the tensile strength parameters of the intermediate layer 12, the overall mechanical properties of the ultrathin plastic film 10 are significantly improved.
In another embodiment of the invention, the metallocene polyethylene is brand XP 1018. Specifically, by selecting the brand of the metallocene polyethylene as XP1018, the better toughness, hot adhesion, heat sealing temperature and low odor of the XP1018 metallocene polyethylene can be benefited, so that the intermediate layer 12 can be ensured to have sufficient mechanical properties, and the odor of the intermediate layer 12 can be reduced, thereby reducing the overall odor of the ultrathin plastic film 10 and improving the environmental protection property of the ultrathin plastic film 10.
In another embodiment of the invention, the metallocene ethylene-hexene copolymer has a weight average molecular weight of from 9 to 16 ten thousand g/mol. Specifically, the metallocene ethylene-hexene copolymer may have a weight average molecular weight of 9 ten thousand g/mol, 9.5 ten thousand g/mol, 10 ten thousand g/mol, 10.5 ten thousand g/mol, 11 ten thousand g/mol, 11.5 ten thousand g/mol, 12 ten thousand g/mol, 12.5 ten thousand g/mol, 13 ten thousand g/mol, 13.5 ten thousand g/mol, 14 ten thousand g/mol, 14.5 ten thousand g/mol, 15 ten thousand g/mol, 15.5 ten thousand g/mol, or 16 ten thousand g/mol. By limiting the weight average molecular weight of the metallocene ethylene-hexene copolymer to 9-16 kg/mol, the mechanical properties of the inner surface layer 11 are ensured, and the blow molding process of the inner surface layer 11 can be stably performed.
In another embodiment of the invention, the metallocene ethylene-hexene copolymer is an enebao 20-05 resin. Specifically, by specifically selecting the metallocene ethylene-ethylene copolymer as the aeoliang 20-05 resin, the advantage of better heat sealability and high stretch ratio of the aeoliang 20-05 resin is obtained, so that the ultra-thin plastic film 10 is ensured to be performed more stably in the blow molding process, and the integrity and the uniformity of the overall performance of the ultra-thin plastic film 10 after blow molding are ensured.
As shown in fig. 2, an embodiment of the present invention further provides a method for manufacturing an ultrathin plastic film 10, including the following steps:
s1: providing the following raw materials of the inner surface layer 11 in parts by weight:
75 to 85 percent of linear low-density polyethylene
12-27% of metallocene ethylene-hexene copolymer
Uniformly mixing the raw materials of the inner surface layer 11 and blow-molding to form an inner surface layer 11 film;
s2: providing the following raw materials for the intermediate layer 12 in parts by weight:
14 to 33 percent of high-density polyethylene
56 to 87 percent of linear low-density polyethylene or metallocene polyethylene
Uniformly mixing the raw materials of the middle layer 12 and blow-molding to obtain a film of the middle layer 12;
s3: providing the following raw materials for the outer surface layer 13 in parts by weight:
15 to 37 percent of bimodal polyethylene
46 to 86 percent of linear low-density polyethylene
Uniformly mixing the raw materials of the outer surface layer 13 and blow-molding to form an outer surface layer 13 film;
s4: and co-extruding the inner surface layer 11 film, the middle layer 12 film and the outer surface layer 13 film to form the ultrathin plastic film 10. Wherein, the inner surface layer 11 film, the middle layer 12 film and the outer surface layer 13 film are co-extruded and molded by adopting three-layer film blowing equipment. Specifically, the length-diameter ratio of a screw of the three-layer film blowing equipment is 25:1 to 35: 1, preferably 30:1, a die gap of 1.8mm to 2.2mm and a blow-up ratio of 2.5. The layer thickness ratio of the inner surface layer 11 film, the intermediate layer 12 film and the outer surface layer 13 film may be 1:1:1 in addition to 3:4:3 or 2:2: 1.
According to the preparation method of the ultrathin plastic film 10 provided by the embodiment of the invention, through multiple tests, reasonable raw material compositions and weight proportions of the inner surface layer 11, the intermediate layer 12 and the outer surface layer 13 are finally determined, the thickness of the ultrathin plastic film 10 prepared by the method is successfully reduced to 0.038-0.045 mm, the mechanical property of the ultrathin plastic film 10 is ensured to be maintained at the original level and not reduced, and the combination firmness of the inner surface layer 11 film, the intermediate layer 12 film and the outer surface layer 13 film is ensured by co-extrusion molding.
The embodiment of the invention also provides an express delivery bag which is prepared from the ultrathin plastic film 10.
The express bag provided by the embodiment of the invention is made of the ultrathin plastic film 10, and the thickness of the ultrathin plastic film 10 is reduced to about 0.04mm, but the mechanical property can be maintained at the original level. Therefore, the thickness of the express bag can be effectively reduced, and the mechanical property of the express bag can be kept unchanged. Therefore, the manufacturing cost of the express bag is obviously reduced while the mechanical property of the express bag is effectively ensured.
In another embodiment of the invention, as shown in the figure, the thickness of the express bag is 0.038mm to 0.045 mm. In particular, the express pouches may have a thickness of 0.0380mm, 0.0385mm, 0.0390mm, 0.0395mm, 0.0400mm, 0.0405mm, 0.0410mm, 0.0415mm, 0.0420mm, 0.0425mm, 0.0430mm, 0.0435mm, 0.0440mm, 0.0445mm, or 0.0450 mm. The thickness of the express bag can be determined according to the actual use requirement, when the use environment of the express bag requires that the express bag has higher mechanical property, the thickness of the express bag can be selected to be 0.040 mm-0.045 mm interval, and when the use environment of the express bag does not require higher mechanical property, the thickness of the express bag can be selected to be 0.038 mm-0.040 mm interval.
Six specific embodiments of the preparation of the ultra-thin plastic film 10 of the present invention are given below:
example 1
Weighing the following raw materials in proportion:
the raw materials of the inner surface layer 11 comprise the following substances in percentage by weight:
80% of linear low-density polyethylene, 17% of metallocene ethylene-hexene copolymer and 3% of black master batch.
The raw materials of the intermediate layer 12 comprise the following substances in percentage by weight:
17% of high-density polyethylene, 68% of linear low-density polyethylene or metallocene polyethylene and 15% of white master batch.
The outer surface layer 13 comprises the following raw materials in percentage by weight:
17% of bimodal polyethylene, 68% of linear low-density polyethylene and 15% of white master batch.
Wherein the weight average molecular weight of the linear low-density polyethylene is 12-13.5 ten thousand g/mol;
the weight average molecular weight of the metallocene polyethylene is 24-26 ten thousand g/mol;
the weight average molecular weight of the metallocene ethylene-hexene copolymer is 11-12 ten thousand g/mol.
The preparation method comprises the following steps:
according to the thickness ratio of the inner surface layer 11, the middle layer 12 and the outer surface layer 13 being 3:4:3, the inner surface layer 11, the middle layer 12 and the outer surface layer 13 are co-extruded and blown to form the ultrathin plastic film 10, and the thickness of the ultrathin plastic film 10 is 0.042 mm.
Example 2
Weighing the following raw materials in proportion:
the raw materials of the inner surface layer 11 comprise the following substances in percentage by weight:
80% of linear low-density polyethylene, 17% of metallocene ethylene-hexene copolymer and 3% of black master batch.
The raw materials of the intermediate layer 12 comprise the following substances in percentage by weight:
17% of high-density polyethylene, 68% of linear low-density polyethylene or metallocene polyethylene and 15% of white master batch.
The outer surface layer 13 comprises the following raw materials in percentage by weight:
17% of bimodal polyethylene, 68% of linear low-density polyethylene and 15% of white master batch.
Wherein the weight average molecular weight of the linear low-density polyethylene is 11-12.5 ten thousand g/mol;
the weight average molecular weight of the metallocene polyethylene is 23-24 ten thousand g/mol;
the weight average molecular weight of the metallocene ethylene-hexene copolymer is 9-11 ten thousand g/mol.
The preparation method comprises the following steps:
according to the thickness ratio of the inner surface layer 11, the middle layer 12 and the outer surface layer 13 being 3:4:4, the inner surface layer 11, the middle layer 12 and the outer surface layer 13 are co-extruded and blown to form the ultrathin plastic film 10, and the thickness of the ultrathin plastic film 10 is 0.040 mm.
Example 3
Weighing the following raw materials in proportion:
the raw materials of the inner surface layer 11 comprise the following substances in percentage by weight:
81% of linear low-density polyethylene, 16% of metallocene ethylene-hexene copolymer and 3% of black master batch.
The raw materials of the intermediate layer 12 comprise the following substances in percentage by weight:
26% of high-density polyethylene, 59% of linear low-density polyethylene or metallocene polyethylene and 15% of white master batch.
The outer surface layer 13 comprises the following raw materials in percentage by weight:
22% of bimodal polyethylene, 63% of linear low-density polyethylene and 15% of white master batch.
Wherein the weight average molecular weight of the linear low-density polyethylene is 13-14 ten thousand g/mol;
the weight average molecular weight of the metallocene polyethylene is 27-29 ten thousand g/mol;
the weight average molecular weight of the metallocene ethylene-hexene copolymer is 13-16 ten thousand g/mol.
The preparation method comprises the following steps:
according to the thickness ratio of the inner surface layer 11, the middle layer 12 and the outer surface layer 13 being 1:2:2, the inner surface layer 11, the middle layer 12 and the outer surface layer 13 are co-extruded and blown to form the ultrathin plastic film 10, and the thickness of the ultrathin plastic film 10 is 0.038 mm.
Example 4
Weighing the following raw materials in proportion:
the raw materials of the inner surface layer 11 comprise the following substances in percentage by weight:
76% of linear low-density polyethylene, 21% of metallocene ethylene-hexene copolymer and 3% of black master batch.
The raw materials of the intermediate layer 12 comprise the following substances in percentage by weight:
15% of high-density polyethylene, 70% of linear low-density polyethylene or metallocene polyethylene and 15% of white master batch.
The outer surface layer 13 comprises the following raw materials in percentage by weight:
34% of bimodal polyethylene, 51% of linear low-density polyethylene and 15% of white master batch.
Wherein the weight average molecular weight of the linear low-density polyethylene is 13-14 ten thousand g/mol;
the weight average molecular weight of the metallocene polyethylene is 25.5-28 ten thousand g/mol;
the weight average molecular weight of the metallocene ethylene-hexene copolymer is 14-16 ten thousand g/mol.
The preparation method comprises the following steps:
according to the thickness ratio of the inner surface layer 11, the middle layer 12 and the outer surface layer 13 being 4:4:3, the inner surface layer 11, the middle layer 12 and the outer surface layer 13 are co-extruded and blown to form the ultrathin plastic film 10, and the thickness of the ultrathin plastic film 10 is 0.038 mm.
Example 5
Weighing the following raw materials in proportion:
the raw materials of the inner surface layer 11 comprise the following substances in percentage by weight:
76% of linear low-density polyethylene, 21% of metallocene ethylene-hexene copolymer and 3% of black master batch.
The raw materials of the intermediate layer 12 comprise the following substances in percentage by weight:
20% of high-density polyethylene, 65% of linear low-density polyethylene or metallocene polyethylene and 15% of white master batch.
The outer surface layer 13 comprises the following raw materials in percentage by weight:
21% of bimodal polyethylene, 64% of linear low-density polyethylene and 15% of white master batch.
Wherein the weight average molecular weight of the linear low-density polyethylene is 11-12 ten thousand g/mol;
the weight average molecular weight of the metallocene polyethylene is 23-26 ten thousand g/mol;
the weight average molecular weight of the metallocene ethylene-hexene copolymer is 11-14 ten thousand g/mol.
The preparation method comprises the following steps:
according to the thickness ratio of the inner surface layer 11, the middle layer 12 and the outer surface layer 13 being 1:1:1, the inner surface layer 11, the middle layer 12 and the outer surface layer 13 are co-extruded and blow-molded to form the ultrathin plastic film 10, and the thickness of the ultrathin plastic film 10 is 0.045 mm.
Example 6
Weighing the following raw materials in proportion:
the raw materials of the inner surface layer 11 comprise the following substances in percentage by weight:
80% of linear low-density polyethylene, 17% of metallocene ethylene-hexene copolymer and 3% of black master batch.
The raw materials of the intermediate layer 12 comprise the following substances in percentage by weight:
17% of high-density polyethylene, 68% of linear low-density polyethylene or metallocene polyethylene and 15% of white master batch.
The outer surface layer 13 comprises the following raw materials in percentage by weight:
17% of bimodal polyethylene, 68% of linear low-density polyethylene and 15% of white master batch.
Wherein the weight average molecular weight of the linear low-density polyethylene is 11-12.5 ten thousand g/mol;
the weight average molecular weight of the metallocene polyethylene is 29-31 ten thousand g/mol;
the weight average molecular weight of the metallocene ethylene-hexene copolymer is 15-16 ten thousand g/mol.
The preparation method comprises the following steps:
according to the thickness ratio of the inner surface layer 11, the middle layer 12 and the outer surface layer 13 being 2:4:2, the inner surface layer 11, the middle layer 12 and the outer surface layer 13 are co-extruded and blown to form the ultrathin plastic film 10, and the thickness of the ultrathin plastic film 10 is 0.043 mm.
The comparative effect of the present invention is illustrated by table 1 below:
performance of Comparative example EXAMPLE 1 EXAMPLE 2 EXAMPLE 3 Example 4 Example 5 Example 6
Thickness of 0.05mm 0.042mm 0.040mm 0.038mm 0.038mm 0.045mm 0.043mm
Tensile strength 26.2MPa 32MPa 32MPa 31MPa 30.5MPa 34.5MPa 33MPa
Breaking force 15N 20N 22N 21N 21N 23N 20.4N
Elongation at break 320％ 410％ 402％ 415％ 412％ 411％ 401％
Puncture strength 1.2N 2.5N 2N 1.9N 2.0N 2.6N 2.2N
Pendulum bob resistance skill 0.95J 1.2J 1.15J 1.02J 1.05J 1.4J 1.2J
Right angle tear force 3N 6N 5.2N 7N 6.5N 7.5N 7N
Heat seal strength 13N 18N 15N 19N 17N 20N 16N
Light transmittance 8％ 4％ 5％ 3.5％ 4％ 6％ 7％
Residual amount of solvent 15mg/m2 9mg/m2 10mg/m2 11mg/m2 10mg/m2 9.5mg/m2 10mg/m2
Apparent whiteness 52％ 62％ 70.5％ 61％ 63％ 64％ 60％
The comparative example is the existing plastic film with the thickness of 0.05mm, and the film layer is made of 61-78% of low-density polyethylene and 17-42% of high-density polyethylene. Table 1 shows that the thickness of the conventional plastic film in the comparative example is higher than that of the ultra-thin plastic film 10 in the six embodiments of the present invention, but the mechanical properties thereof are behind those of the ultra-thin plastic film 10 in the six embodiments of the present invention, so that it is demonstrated that the mechanical properties of the ultra-thin plastic film 10 in the six embodiments of the present invention are superior.
The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (12)

1. An ultra-thin plastic film characterized by: the composite material comprises an inner surface layer, a middle layer and an outer surface layer which are sequentially combined, wherein the inner surface layer comprises the following components in percentage by weight of 100 percent of raw materials:
75 to 85 percent of linear low-density polyethylene
12 to 27 percent of metallocene ethylene-hexene copolymer;
the intermediate layer comprises the following components in percentage by weight of 100 percent of raw materials:
14 to 33 percent of high-density polyethylene
54% -87% of linear low-density polyethylene or metallocene polyethylene;
the outer surface layer comprises the following components in percentage by weight of 100 percent of raw materials:
15 to 37 percent of bimodal polyethylene
46 to 86 percent of linear low density polyethylene.
2. The ultra-thin plastic film of claim 1, wherein: the raw material of the inner surface layer also comprises black master batch, wherein the black master batch accounts for 2-5 wt% of the inner surface layer.
3. The ultra-thin plastic film of claim 1, wherein: the raw materials of the middle layer and the outer surface layer both comprise white master batches, and in the middle layer, the white master batches account for 12-20% of the weight of the middle layer;
in the outer surface layer, the white master batch accounts for 14-25 wt% of the outer surface layer.
4. The ultra-thin plastic film of claim 1, wherein: the thickness ratio of the inner surface layer, the middle layer and the outer surface layer is (2-4): 3-5): 2-4.
5. The ultra-thin plastic film of claim 4, wherein: the thickness ratio of the inner surface layer, the middle layer and the outer surface layer is 3:4: 3.
6. The ultra-thin plastic film of claim 4, wherein: the thickness ratio of the inner surface layer, the middle layer and the outer surface layer is 2:2: 1.
7. The ultra-thin plastic film as claimed in any one of claims 1 to 6, wherein: the weight average molecular weight of the linear low-density polyethylene is 11-14 ten thousand g/mol.
8. The ultra-thin plastic film as claimed in any one of claims 1 to 6, wherein: the weight average molecular weight of the metallocene polyethylene is 23-31 ten thousand g/mol.
9. The ultra-thin plastic film as claimed in any one of claims 1 to 6, wherein: the weight average molecular weight of the metallocene ethylene-hexene copolymer is 9-16 ten thousand g/mol.
10. A preparation method of an ultrathin plastic film is characterized by comprising the following steps: the method comprises the following steps:
s1: providing the following raw materials in parts by weight for the inner surface layer:
75 to 85 percent of linear low-density polyethylene
12-27% of metallocene ethylene-hexene copolymer
Uniformly mixing the raw materials of the inner surface layer and blow-molding the raw materials of the inner surface layer into an inner surface layer film;
s2: providing the following raw materials of the middle layer in parts by weight:
14 to 33 percent of high-density polyethylene
56 to 87 percent of linear low-density polyethylene or metallocene polyethylene
Uniformly mixing the raw materials of the middle layer and blow-molding to form a middle layer film;
s3: providing the following raw materials of the outer surface layer in parts by weight:
15 to 37 percent of bimodal polyethylene
46 to 86 percent of linear low-density polyethylene
Uniformly mixing the raw materials of the outer surface layer and blow-molding to form an outer surface layer film;
s4: co-extruding the inner surface layer film, the intermediate layer film and the outer surface layer film to form the ultrathin plastic film.
11. An express delivery bag which is characterized in that: the ultrathin plastic film as claimed in any one of claims 1 to 9.
12. The courier bag of claim 11, wherein: the thickness of the express bag is 0.038 mm-0.045 mm.
CN201910778380.4A 2019-08-22 2019-08-22 Ultrathin plastic film, preparation method of ultrathin plastic film and express bag Pending CN112406228A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113602666A (en) * 2021-08-13 2021-11-05 上海华悦包装制品有限公司 Durable standing bag

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5709932A (en) * 1994-11-21 1998-01-20 Bollore Technologies Ultra thin heat-shrinkable monolayer polyethylene films
CN109016761A (en) * 2018-08-10 2018-12-18 顺丰速运有限公司 Plastic foil and courier bag

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5709932A (en) * 1994-11-21 1998-01-20 Bollore Technologies Ultra thin heat-shrinkable monolayer polyethylene films
CN109016761A (en) * 2018-08-10 2018-12-18 顺丰速运有限公司 Plastic foil and courier bag

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113602666A (en) * 2021-08-13 2021-11-05 上海华悦包装制品有限公司 Durable standing bag

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