CN216183487U

CN216183487U - High-toughness high-transparency composite film material structure

Info

Publication number: CN216183487U
Application number: CN202122534271.3U
Authority: CN
Inventors: 辜伟悦
Original assignee: Zhuhai Hengqin Huizefeng Packaging Technology Co ltd
Current assignee: Zhuhai Hengqin Huizefeng Packaging Technology Co ltd
Priority date: 2021-10-21
Filing date: 2021-10-21
Publication date: 2022-04-05
Anticipated expiration: 2031-10-21

Abstract

The utility model provides a high-toughness and high-transparency composite film material structure, which comprises a natural cellulose layer, a BOPLA layer and an adhesive layer clamped between the natural cellulose layer and the BOPLA layer, wherein the natural cellulose layer, the adhesive layer and the BOPLA layer are combined together through a composite film-forming technology, and the natural cellulose layer, the adhesive layer and the BOPLA layer are all biodegradable materials. According to the utility model, the BOPLA layer which is relatively temperature-resistant, has heat-sealing property and strong tensile resistance, but has poor extensibility, high hardness and transparency and the natural cellulose layer which has good temperature resistance, good printing performance, good toughness and high transparency are compounded together through the adhesive layer, and the performances of the BOPLA layer and the natural cellulose layer are complementary to each other, so that the transparent composite film material which has good surface wetting tension, good surface temperature-resistant inner layer, heat-sealing property, high transparency, toughness and biodegradability and can be printed according to requirements can be prepared. The main raw material is completely derived from biological raw materials, can be degraded completely and is a carbon neutralization product, and the method is energy-saving and environment-friendly.

Description

High-toughness high-transparency composite film material structure

Technical Field

The utility model relates to the technical field of degradable film materials, in particular to a high-toughness high-transparency composite film material structure.

Background

At present, the degradable packaging film is a good packaging material in the market and gradually replaces the plastic film under the push of environmental protection concept and plastic limitation. The degradable film material is mainly applied to a single-layer film at present, the single-layer application cannot meet more functional requirements, and the completely degradable film raw material is multisourced to natural substances and has performance defects, so that the degradable film material cannot meet diversified packaging application.

Disclosure of Invention

The utility model aims to overcome the defects of the prior art and provide a biodegradable composite film material which solves the problem of environmental pollution caused by non-degradable plastics and simultaneously meets the requirement of functional packaging application.

In order to achieve the purpose, the technical scheme provided by the utility model is as follows: the composite film material structure comprises a natural cellulose layer, a BOPLA layer and an adhesive layer clamped between the natural cellulose layer and the BOPLA layer, wherein the natural cellulose layer, the adhesive layer and the BOPLA layer are combined together through a composite film-forming technology, and the natural cellulose layer, the adhesive layer and the BOPLA layer are all biodegradable materials.

Preferably, a printing layer is further arranged between the natural cellulose layer and the adhesive layer.

Preferably, a pure aluminum foil layer is further arranged between the cellulose layer and the BOPLA layer, the adhesive layers are respectively clamped between the natural cellulose layer, the pure aluminum foil layer and the BOPLA layer, and the natural cellulose layer, the pure aluminum foil layer, the BOPLA layer and the adhesive layers respectively clamped between the natural cellulose layer, the pure aluminum foil layer and the BOPLA layer are combined together through a composite film forming technology.

Preferably, a PBAT layer is also provided outside the BOPLA layer.

Preferably, a PBS layer is arranged outside the BOPLA layer.

Preferably, an aluminum plating layer may be added outside the natural cellulose layer and the BOPLA layer.

Preferably, a PVDC coating can be added outside the native cellulose layer and the BOPLA layer.

Preferably, the adhesive layer is a polyurethane adhesive.

According to the scheme, the BOPLA layer which is relatively temperature-resistant, has high heat sealability and tensile resistance, but is poor in extensibility and high in hardness and transparent and the natural cellulose layer which is good in temperature resistance, printing performance, toughness and transparency are compounded together through the adhesive layer, the performances of the BOPLA layer and the natural cellulose layer are complementary, and the BOPLA layer and the natural cellulose layer can be prepared into the transparent composite film material which is good in surface wetting tension, good in surface temperature-resistant inner layer, capable of being heat-sealed, capable of being printed according to requirements, high in transparency, high in toughness and biodegradable. The main raw material is completely derived from biological raw materials, can be degraded completely and is a carbon neutralization product, and the method is energy-saving and environment-friendly.

Description of the drawings:

FIG. 1 is a first schematic structural diagram of a composite film material according to the present invention;

FIG. 2 is a schematic view of a composite film material structure of the present invention;

FIG. 3 shows a schematic view of the structure of the composite film material of the present invention;

FIG. 4 is a schematic view of a preparation process of the present invention;

FIG. 5 is a simplified schematic view of the process flow of the dry compounding method of the present invention;

FIG. 6 is a simplified schematic diagram of the process flow of the solvent-free compounding method of the present invention.

Detailed Description

The utility model will be further illustrated with reference to specific examples:

example 1:

as shown in fig. 1, in the structure of the tough high-transparency composite film material 1 according to the present embodiment, the composite film material 1 includes a natural cellulose layer 2, a BOPLA layer 3, and an adhesive layer 4 sandwiched between the natural cellulose layer 2 and the BOPLA layer 3, the natural cellulose layer 2, the adhesive layer 4, and the BOPLA layer 3 are combined together by a composite film forming technology, and the natural cellulose layer 2, the adhesive layer 4, and the BOPLA layer 3 are all biodegradable materials.

The natural cellulose layer 2 is commonly known as cellophane, which is synthesized from cellulose and diaphane, and has good printability. It was invented in 1905 by brandeberg, a textile engineer in switzerland. It is a natural cellulose film with high transparency and luster, also called as 'regenerated cellulose film' made by using dissolving pulp made of natural fibers such as cotton linters and chemical woods as raw materials and by a viscose method. The term "regenerated" means not reused, but a cellulose film produced by producing a glue by a viscose method and rearranging molecular chains.

The production method of the natural cellulose layer 2, namely the glassine paper is different from the papermaking and is similar to the artificial silk process. The method is characterized in that cotton linter dissolving pulp or refined chemical wood pulp with high alpha-cellulose content is used as a raw material, alkali cellulose is prepared through processes of alkalization (18% sodium hydroxide), squeezing, crushing and the like, carbon disulfide is added after aging to be yellowed into cellulose xanthate, and sodium hydroxide solution is used for dissolving to prepare the orange cellulose viscose. The viscose is subjected to ripening treatment at the temperature of 20-30 ℃, filtered to remove impurities and remove bubbles, extruded out in a long, narrow and fine gap in a film forming machine, flowed into a coagulating bath of mixed solution of sulfuric acid and sodium sulfate to form a film (regenerated cellulose film), subjected to water washing, desulfurization, bleaching, desalination, softening (glycerol, ethylene glycol and the like), coloring and the like, and finally dried to prepare the viscose. In the production process, chemicals such as acid, alkali, carbon disulfide and the like are used, but the chemicals are not contained after treatment, and the main components of the product are as follows: about 82% of fiber, about 8% of moisture and about 10% of softening agent. The volume weight per square meter is 16-80 g/square meter, the conventional production is 20-60 g/square meter, and the specifications of the flat plate and the winding drum can be cut according to the user requirements.

The cellophane is degradable: tests of Zhejiang industry and commerce university show that 'when the membrane product is buried in soil for 45 days, the membrane is extremely seriously disintegrated and is cracked together with the soil during digging, and the degradation weight loss rate of the membrane cannot be measured'; secondly, the coating is nontoxic and tasteless, and the film product has no dense smoke and stink when burning; good insulating property (surface resistance of 8.2 x 107 omega), no static electricity, dust resistance and good printing adaptability; fourthly, the air permeability is good: the average oxygen permeability is 67.018 cc/square meter day, and the film is made of cellulose, has pores and is suitable for fresh-keeping storage of fruits, vegetables and the like. High temperature resistance: the oven is kept at 200 ℃ for 24 hours without deformation. The natural cellulose layer 2 is applied to the composite material with a thickness of between 10UM and 50 UM.

The main component of the BOPLA layer 3 is a transparent film product prepared by polylactic acid extracted and synthesized from corn, sugarcane and cassava through a biaxial stretching process, and the BOPLA layer 3 has high tensile strength, good stiffness, good flatness, good surface printing performance and better temperature resistance compared with the natural cellulose layer 2. The thickness of the BOPLA layer 3 is 12UM-100 UM.

The adhesive layer 4 can be polyurethane adhesive, and the BOPLA layer 3 and the natural cellulose layer 2 can be bonded into a whole through traditional dry compounding or solvent-free compounding. The polyurethane adhesive has heat resistance and cold resistance, can bear the temperature requirements of bag making, boiling and stewing, and can also bear the temperature requirements of low-temperature refrigeration or freezing storage (has lower embrittlement temperature); the adhesive is nontoxic, odorless, good in fluidity and leveling property and good in adhesive force on used composite materials, and can bear the corrosion of contents and various media in the environment.

The BOPLA layer 3 is a two-way stretching polylactic acid, has good printing adaptability and tensile property, but has poor extensibility; the natural cellulose layer 2 is inferior in temperature resistance and tensile strength, but has heat sealability and extensibility. 2 materials are completely from degradable films of biological raw materials, are bonded into a whole through the adhesive layer 4, and have complementary performances, so that the transparent composite film material 1 which is temperature-resistant, heat-sealable, recyclable and biodegradable is prepared; in addition, the carbon fiber composite material can be printed according to requirements, and can be processed into packaging bags or packaging films and other materials with strong comprehensive performance according to the composite process, the main raw materials are completely derived from biological raw materials, and the carbon fiber composite material can be degraded completely and is a carbon neutralization product, so that the energy is saved and the environment is protected.

As shown in Table 1, the comparison of single modified cellulose film material, BOPLA film material, and composite BOPLA + PBAT, cellulose + PBAT, modified PLA + BOPLA, and cellulose + BOPLA shows that the cellulose + BOPLA composite material has higher toughness and transparency, higher tensile property and good heat sealability, improves the properties of surface temperature resistance, tensile resistance and the like of a finished product, achieves the properties of a common plastic film, and is not easy to break.

The thickness of the prepared composite film material 1 is between 25UM and 250UM, and the prepared composite film material 1 can be prepared into food packaging bags (the composite strength is more than or equal to 1.5N), vacuum-pumping packaging bags (the heat sealing strength is more than or equal to 10N), freezing bags (below 10 ℃), industrial product packaging bags, degradable film materials for various industries and the like.

TABLE 1 comparison of Performance of Single film Material products with composite film Material 1

Thin film structure

Environmental protection performance

Is transparentDegree of rotation

Printing layer

5A

Tensile Strength MPA

Source of raw materials

Heat-sealing temperature (. degree.C.)

Modified cellulose film material

Recyclable and degradable material

Greater than 90 percent

Outer surface

＜40

Bio-based

120 unsealing

BOPLA film material

Recyclable and degradable material

Greater than 90 percent

Outer surface

＞50

Bio-based

155 unsealing

BOPLA composite PBAT

Recyclable and degradable material

Less than 85 percent

Can be printed on the middle layer to meet the requirement of food packaging

＞50

Biobased + petroleum based

120 unsealing

Cellulose composite PBAT

Non-recyclable degradable

Less than 85 percent

Can be printed on the middle layer to meet the requirement of food packaging

＞40

Plant base and petroleum base

120 unsealing

PLA composite BOPLA

Recyclable and degradable material

More than 85% and less than 90%

Can be printed on the middle layer to meet the requirement of food packaging

＞50

Bio-based

120 unsealing

This patent complex film

Non-recyclable degradable

Greater than 90 percent

Can be printed on the middle layer to meet the requirement of food packaging

＞70

Biological plus plant base

155 degree unsealing

As shown in fig. 2, a printed layer 5A is further provided between the natural cellulose layer 2 and the adhesive layer 4, and the printed layer 5A is provided on the inner surface of the natural cellulose layer 2, that is, the printing is performed on the inner surface of the natural cellulose layer 2. The composite film material 1 can be printed with characters and patterns, and can meet the environmental protection requirements of foods and medicines by being internally printed on the inner surface of the natural cellulose layer 2. The composite film material 1 is compounded after being printed, and the ink layer is prevented from being damaged by direct friction, scratches and various corrosive substances because the ink is clamped in the middle of the film layer, so that the problems of color bleeding and color fading in degradable film printing are solved well, and the safety and sanitation problems caused by direct contact of the ink with food and medicines are avoided.

If the printing layer 5A has requirements on corona strength, the surfaces of the BOPLA layer 3 and the natural cellulose layer 2 can be subjected to corona treatment, so that the adhesive force of the printing layer 5A ink or adhesive is enhanced.

As shown in fig. 3, a pure aluminum foil layer 5B may be added between the natural cellulose layer 2 and the BOPLA layer 3 by a composite film forming technique, so as to increase the barrier property of the composite film material 1, the adhesive layers 4 are respectively sandwiched between the natural cellulose layer 2, the pure aluminum foil layer 5B, and the BOPLA layer 3, and the natural cellulose layer 2, the pure aluminum foil layer 5B, BOPLA layer 3, and the adhesive layers 4 respectively sandwiched between the natural cellulose layer 2, the pure aluminum foil layer 5B, and the BOPLA layer 3 are combined together by the composite film forming technique.

When the base material is coated with high barrier property, an alumina coating or a PVDC coating, an alumina coating or an aluminum coating can be added outside the natural cellulose layer 2 and the BOPLA layer 3 to meet the application requirement of high barrier property.

In order to increase the heat seal strength of the composite film material 1, a PBAT layer or a PBS layer may be further provided outside the BOPLA layer 3.

Selecting a natural cellulose layer and a BOPLA layer which meet the degradation requirement, and meeting but not limited to the following international authoritative degradation certification:

● Germany DIN EN13432

● USA BPI ASTM D6400

● Belgium OK COMPOSTABLE

● Australia Acam.

The performance of the polyurethane adhesive adopted by the composite adhesive meets but is not limited to the following health and safety regulations:

● Chinese food packaging material additive rule GB9685-2008

● American Food and Drug Administration (FDA)21CFR175.300

● EU ROHS hazardous substances restriction directive

When the composite membrane is prepared, the natural cellulose layer or the BOPLA layer can be set as a gluing surface, namely a first base material, and the natural cellulose layer or the BOPLA layer is coated with an adhesive layer and then is attached to another material.

As shown in fig. 4, there are two processes suitable for the composite film material 1: dry compounding and solvent-free compounding.

The dry-type compounding method comprises the steps of firstly coating a layer of solvent-type adhesive on a first layer of film by using a gravure screen line roller, drying and drying the solvent-type adhesive to remove the solvent in the drying process, and then compounding a second layer of film, the first layer of film and the adhesive into a whole in a hot-pressing state.

The dry lamination method is suitable for lamination of various films, has excellent chemical corrosion resistance, and is widely applied to packaging with relatively harsh content conditions, such as foods containing basic, acidic, spicy, and grease components, cosmetics containing essence, emulsifier components, and chemicals containing corrosive solvents, pesticides, and the like.

The dry compounding method has the following characteristics: the composite film has the advantages of good stability, high strength, high transparency, flexible and convenient process and simple manufacture, can be used for producing common composite films, and can also be used for producing composite films with special functions such as freezing, fresh-keeping or high-temperature sterilization.

The dry compounding method comprises the following steps: as shown in fig. 5, in the dry lamination preparation method of the tough high-transparency composite film material structure, the first substrate passes through a coating mechanism composed of a rubber disc 6, a scraper, a gravure roll 7 and a rubber press roll i 8, the first substrate is generally the BOPLA layer 3, after the surface of the first substrate is coated with the solvent-based adhesive layer 4, the first substrate enters a drying tunnel 9 to dry the solvent-based adhesive layer 4 to remove the solvent, the temperature of the drying tunnel 9 is 40-60 ℃, then the first substrate enters a hot press mechanism composed of the heating steel roll 11 and a rubber press roll ii 10, the second substrate is hot-pressed on the solvent-based adhesive layer 4, the natural cellulose layer 2, the adhesive layer 4 and the BOPLA layer 3 are pressed together, the temperature of the heating steel roll 11 is 40-60 ℃, and the lamination pressure of the hot press mechanism is under the condition that the film is not damaged, the pressure is increased as much as possible, and finally the composite film I14 is obtained through a cooling roller 12; and curing the composite film I14 to obtain the composite film material 1.

The solvent-free compounding method comprises the steps of firstly coating a solvent-free polyurethane adhesive on a first base material by using a coating roller, wherein the viscosity of the solvent-free polyurethane adhesive is higher at normal temperature, the viscosity is sharply reduced along with the temperature rise, the solvent-free polyurethane adhesive has good coating performance, the moisture of air can be used as a curing agent, the adhesive strength is good, then the viscosity of the solvent-free polyurethane adhesive is reduced in a hot pressing state, the solvent-free polyurethane adhesive is coated on the first base material (the gluing amount is 1-4 g/square meter), and finally, a second layer of film, a first layer of film and the adhesive are compounded together in a hot pressing mode, and the like.

The adhesive prepared by the solvent-free compounding method does not contain an organic solvent, and a drying device is not needed.

The solvent-free compounding method comprises the following steps: as shown in fig. 6, after passing through a coating mechanism composed of a rubber disc 6, a scraper, a coating roller 13 and a rubber press roller i 8, under the belt of a guide roller, the first substrate is coated with the adhesive layer 4 on the surface thereof and sent to a hot press mechanism composed of a heating steel roller 11 and a rubber press roller ii 10, the second substrate is hot-rolled on the adhesive layer 4, so that the natural cellulose layer 2, the adhesive layer 4 and the BOPLA layer 3 are pressed together, the heating steel roller 11 is at a temperature of 40-60 ℃, the composite pressure of the hot press mechanism is increased as much as possible without damaging the film, and finally, a composite film ii 15 is obtained through the cooling roller 11; and curing the composite film II 15 to obtain the composite film material 1.

The adhesive layer 4 can be bonded to the natural cellulose layer 2 and the BOPLA layer 3, respectively, because when the adhesive layer 4 is bonded to the natural cellulose layer 2 and the BOPLA layer 3, an adhesive force is generated in a drying curing (with a solvent polyurethane adhesive) or a heating curing (without a solvent polyurethane adhesive), that is, in a compounding process, the adhesive layer 4 enters the natural cellulose layer 2 and the BOPLA layer 3 under a pressed condition to form an adhesive force therebetween, and an adhesive effect is affected by factors such as a speed, a scraper distance, a solvent formula, and pressure distribution in the compounding process.

The composite film I14 and the composite film II 15 obtained by the dry-type composite method and the solvent-free composite method both need to be subjected to a curing process, the curing process can be carried out in a constant temperature room with the temperature of 35-50 ℃ for more than 6 hours, and the chemical reaction speed can be accelerated by increasing the temperature.

The curing reaction is beneficial to curing of the adhesive layer 4, and is beneficial to accelerating the mutual reaction of-NCO groups in the adhesive layer 4 and active hydrogen groups on the surfaces of the natural cellulose layer 2 and the BOPLA layer 3. The adhesive layer 4 can be softened by heating, so that the surfaces of the natural cellulose layer 2 and the BOPLA layer 3 are wetted, molecular motion is facilitated, the adhesive force is improved, a product can be rapidly subjected to subsequent processing, and the production period is shortened. Before the curing reaction is completed, the peel strength of the composite film I and the composite film II is changed, and the process of increasing-attenuating-stabilizing is presented.

The curing reaction process can be continued for more than 48 hours in a natural environment at 25 ℃ to achieve the purpose of curing.

The peel strength of the cured composite film material 1 can reach more than 1.5N-2N.

Claims

1. A high-toughness high-transparency composite film material structure is characterized in that: the composite film material comprises a natural cellulose layer, a BOPLA layer and an adhesive layer clamped between the natural cellulose layer and the BOPLA layer, wherein the natural cellulose layer, the adhesive layer and the BOPLA layer are combined together through a composite film-forming technology, and the natural cellulose layer, the adhesive layer and the BOPLA layer are all biodegradable materials.

2. The strong toughness high transparency composite film material structure according to claim 1, characterized in that: and a printing layer is also arranged between the natural cellulose layer and the adhesive layer.

3. The strong toughness high transparency composite film material structure according to claim 1, characterized in that: and the adhesive layers are respectively clamped among the natural cellulose layer, the pure aluminum foil layer, the BOPLA layer and the adhesive layers respectively clamped among the natural cellulose layer, the pure aluminum foil layer and the BOPLA layer, and the natural cellulose layer, the pure aluminum foil layer, the BOPLA layer and the adhesive layers are combined together through a composite film-forming technology.

4. The strong toughness high transparency composite film material structure according to claim 1, characterized in that: a PBAT layer is also arranged outside the BOPLA layer.

5. The strong toughness high transparency composite film material structure according to claim 1, characterized in that: and a PBS layer is arranged outside the BOPLA layer.

6. The strong toughness high transparency composite film material structure according to claim 1, characterized in that: an aluminum plating layer can be added outside the natural cellulose layer and the BOPLA layer.

7. The strong toughness high transparency composite film material structure according to claim 1, characterized in that: a PVDC coating can be added over the native cellulose layer and the BOPLA layer.

8. The strong toughness high transparency composite film material structure according to any one of claims 1 to 7, wherein: the adhesive layer is a polyurethane adhesive.