CN218477252U

CN218477252U - High-transparency high-barrier full-biodegradable composite film material structure

Info

Publication number: CN218477252U
Application number: CN202222665664.2U
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: 2022-10-11
Filing date: 2022-10-11
Publication date: 2023-02-14
Anticipated expiration: 2032-10-11

Abstract

The utility model provides a full biodegradable composite film material structure of high transparent high separation, composite film structure include that area coating cellulose thin layer, modified PLA thin layer and centre gripping take the adhesive layer between coating cellulose thin layer and the modified PLA thin layer, combine together through compound film forming technology between area coating cellulose thin layer, adhesive layer and the modified PLA thin layer. The utility model discloses will have high oxygen resistance and water resistance, printing adaptability, the temperature resistance, the stretching resistance is strong, but the extensibility is poor, the high band coating cellulose thin layer of hardness with have high transparency, better heat sealability and extensibility, but the relatively poor modified PLA thin layer of temperature resistance passes through the adhesive complex and is in the same place, mutual performance is complementary, it is good to prepare into surface wetting tension, but the temperature resistance is heat-sealable, but high separation and biodegradable's high transparent composite film material structure, the main raw materials is derived from biological raw materials completely, can thoroughly degrade, energy-concerving and environment-protective, be the environmental protection product that has using value.

Description

High-transparency high-barrier full-biodegradable composite film material structure

Technical Field

The utility model relates to a combined material technical field especially involves a full biodegradable composite film material structure of high transparent high separation.

Background

The recyclability and the degradability of the flexible package become two major directions for solving the industrial pollution, and the flexible package solves the problem of functionality, and simultaneously, along with the improvement of the living standard of people, the people have the high-barrier packaging requirements for visual transparent food packaging and prolonging the quality guarantee period of the food. While consumers are more concerned about visibility of the contents of the package, the visual experience, relative to recyclability and degradability.

At present, the most common transparent high-barrier flexible packages are single-layer material packages and multi-layer composite materials, and recently, the more popular transparent high-barrier single-material multi-layer composite packaging materials, such as BOPE/EVOHEP materials, are recyclable but non-degradable packaging materials. The single-layer high-barrier transparent material has low packaging cost, can be recycled but is not degradable, and is difficult to meet the packaging requirement of high barrier property; the single-material multilayer composite packaging material and the single-layer material are both convenient to recycle, but the single-material multilayer composite packaging material is not degradable, and the single-material multilayer composite packaging material is difficult to clean after being recycled, so that a more polluted water source can be caused; the multilayer degradable composite material can better meet more packaging requirements, but the existing multilayer degradable composite material has high barrier property, high transparency and poor barrier property.

SUMMERY OF THE UTILITY MODEL

The utility model aims at using the degradable film of different performance advantages to make up through the combined technology, reach non-degradation type multilayer composite packaging material equal performance to can degrade completely through the industry compost after making the packing abandon, reach the security performance of the high separation of packing, be harmless ecological environment and human health simultaneously, resources are saved protects the environment, accords with sustainable development direction, accords with transparent visual consumer experience simultaneously and feels.

In order to achieve the above purpose, the utility model provides a technical scheme does: the high-transparency high-barrier full-biodegradable composite film material structure comprises a coated cellulose film layer, a modified PLA film layer and an adhesive layer clamped between the coated cellulose film layer and the modified PLA film layer, wherein the coated cellulose film layer, the adhesive layer and the modified PLA film layer are combined together through a composite film forming technology.

Preferably, the coated cellulose film layer includes a natural cellulose film layer and PVDC coatings coated on upper and lower surfaces of the natural cellulose film layer.

Preferably, the coated cellulose film layer includes a natural cellulose film layer and alumina coatings coated on upper and lower surfaces of the natural cellulose film layer.

Preferably, the coated cellulose film layer includes a natural cellulose film layer and acrylic coatings coated on upper and lower surfaces of the natural cellulose film layer.

Preferably, an alumina coating is coated on the surface of the modified PLA film layer.

Preferably, a printing layer is further arranged between the coated cellulose film layer and the adhesive layer, and the printing layer is arranged on the inner surface of the coated cellulose film layer.

The utility model discloses it hinders water proofly to have high oxygen, printing adaptability, the temperature resistance, the stretching resistance is strong, but the extensibility is poor, the high band coating cellulose thin layer of hardness with have high transparency, better heat sealability and extensibility, but the relatively poor modified PLA thin layer of temperature resistance passes through the adhesive complex and is in the same place, the performance is complementary each other, it is good to prepare into the moist tension in surface, but surface temperature resistance heat-seal, but high resistant high transparent composite film material structure of separating just biodegradable, the main raw materials derives from biological raw materials completely, the membrane material of making can thoroughly degrade, energy saving and environmental protection, the environmental protection product that has popularization and application value.

Description of the drawings:

fig. 1 is a schematic view of a composite film structure of the present invention;

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

fig. 3 is a schematic view of the structure of the composite film of the present invention;

fig. 4 is a schematic view of a fourth exemplary structure of the composite film of the present invention;

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

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

Detailed Description

The invention will be further described with reference to the following specific embodiments:

example 1:

as shown in fig. 1-3, the high-transparency high-barrier fully biodegradable composite film structure of the present embodiment includes a coated cellulose film layer 1, a modified PLA film layer 2, and an adhesive layer 3 sandwiched between the coated cellulose film layer 1 and the modified PLA film layer 2, and the coated cellulose film layer 1, the adhesive layer 3, and the modified PLA film layer 2 are combined together by a composite film forming technique.

The coated cellulose film layer 1 comprises a natural cellulose film layer 1A, and a PVDC coating 1B or an alumina coating 1C and an acrylic coating 1D coated on the upper surface and the lower surface of the natural cellulose film layer 1A.

The natural cellulose film is commonly called cellophane, english name cellophane, has good printing adaptability, and is a high-transparency and high-gloss natural cellulose film, also called 'regenerated cellulose film', made of dissolving pulp made of natural fibers such as cotton linter and chemical wood as raw material by 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 natural cellulose membrane (cellophane) is different from paper-making, and is similar to 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 the orange-colored cellulose viscose is prepared through dissolution by using a sodium hydroxide solution. The viscose is ripened at 20-30 deg.C, filtered to remove impurities and bubbles, extruded in a narrow and small 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), washed, desulfurized, bleached, desalted, softened (glycerol, glycol, etc.), colored, etc., and finally dried to obtain the viscose. Chemicals such as acid, alkali, carbon disulfide and the like are used in the production process, but the chemicals are not contained after treatment.

The natural cellulose film (1), called "cellophane", is degradable: the Zhejiang university test shows that the film product has serious fragmentation when buried in soil for 45 days, and the film product is cracked with the soil during digging, so that the degradation weight loss rate of the film cannot be measured; (2) the coating is nontoxic and odorless, and the film product has no dense smoke and odor during combustion; (3) the printing ink has good insulativity (surface resistance of 8.2 multiplied by 107 omega), does not have static electricity, is not easy to be stained with dust and has good printing adaptability; (4) has good air permeability: the average oxygen permeability is 67.018 cc/square meter, day, because it is made of cellulose, the film has pores and pores, and is suitable for fresh-keeping storage of fruits and vegetables. (5) High temperature resistance: the oven is kept at 200 ℃ for 24 hours without deformation.

The natural cellulose membrane has certain air permeability and larger elongation, is not fire-resistant but high-temperature resistant, can not deform at the high temperature of more than 190 ℃, can be sterilized at high temperature together with food in food packaging, and is very favorable for the fresh-keeping and preservation activity of the food; the natural fiber membrane has strong resistance to oily, alkaline and organic solvents, air, oil, bacteria and water are not easy to permeate through the natural fiber membrane layer, the oil barrier property is high, and the natural fiber membrane is made of natural fibers, can absorb water and is easy to decompose when being discarded; the high transparency of the coating enables the goods to be seen clearly, and the surface of the coating can meet the packaging requirements of more severe conditions after being coated with functional coating.

The cellulose film layer 1 with the coating is prepared by coating PVDC or alumina and acrylic acid on a natural cellulose film base film so as to enhance the barrier property of water and oxygen permeation and keep the high transparency of the base film. The PVDC is a commonly-called 'K layer' and has excellent capability of blocking water vapor, oxygen, smell and fragrance under any temperature or humidity condition, and the PVDC coating 1B can provide safe gas barrier and moisture barrier properties for a base film, delay the oxidative deterioration of food, prolong the shelf life of the food and avoid the fragrance loss of contents and the invasion of external bad smell; the moisture resistance can prevent the contents from drying out due to water loss and damage the packaging prototype due to moisture absorption. The aluminum oxide layer has excellent barrier property, the freshness and aroma keeping performance of food is obviously improved, the shelf life of the food can be prolonged, and the aluminum oxide coating 1C and the acrylic acid can play the same role. The thickness of the coated cellulose film applied to the composite film structure is between 10UM and 50 UM.

The modified PLA film layer 2 is a degradable material with good comprehensive performance, the single PLA film has poor processability, the obtained PLA film has poor toughness, lacks elasticity and flexibility, has hard and brittle texture, and is limited to be applied in many aspects, but the PLA film has high transparency. The modified PLA film layer 2 is mainly prepared by taking PLA as a main material and blending the PLA with PBS and PHA, for example, the PBS/PLA/PHA biodegradable composite material of ZL201610298331.7 and the preparation method thereof can improve the processability of film blowing or film casting without damaging the biodegradability of the composite material. The film material prepared by blending modification has excellent mechanical property, improves barrier property and weather resistance, and is more suitable for post processing and packaging application. The thickness of modified PLA film layer 2 is between 15UM and 200UM, is used as the heat-seal layer in the utility model discloses.

The adhesive layer 3 is a polyurethane adhesive, and the coated cellulose film layer and the modified PLA film layer 2 are bonded into a whole through a dry-type compounding or solvent-free compounding process. 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 coated cellulose film layer 1 has excellent barrier property, good surface temperature resistance, printing adaptability and tensile property, but poor extensibility; the modified PLA film layer 2 has high transparency, good heat sealability and extensibility, but the temperature resistance and the tensile resistance are poor, the two film materials are degradable films, and the two film materials are bonded into a whole through an adhesive, and the performances are complementary to each other, so that the high-barrier heat-resistant heat-sealable biodegradable composite film material is prepared. The printing of the patterns on the coating cellulose layer can be carried out according to the packaging requirements, and then the composite processing is carried out, so that the packaging is more qualified, the display capacity of the goods shelf is improved, and the goods are endowed with greater value.

As shown in table 1, from the modified PLA film material of individual layer (blown film or curtain coating), BOPLA film material (biaxial stretching PLA) and BOPLA/PBAT, cellulose/PBAT and the utility model discloses a contrast of taking coating cellulose/modified PLA composite film shows that the utility model discloses a composite film structure not only reaches the performance of general plastics composite film at tensile resistance, heat sealability, and its separation nature also shows better. The high transparency can meet the visual requirement of the content by matching with the printing design, and the visual attraction is improved.

Table 1: comparison of Single layer film Material products with composite film materials

The utility model discloses a composite film structure thickness is between 40UM to 250UM, and the food package bag (combined strength is more than or equal to 1.5N), the evacuation wrapping bag (heat-seal strength is more than or equal to 10N), freezing bag (-10 ℃) of system bag gained can wide application in food package, industrial packaging and other packing fields.

As shown in fig. 3, a printing layer 4 is further disposed between the coated cellulose film layer 1 and the adhesive layer 3, and the printing layer 4 is disposed on the inner surface of the coated cellulose film layer 1, that is, an inner printing method is adopted. The inner printing is that the ink is sandwiched between the film layers, so that the ink layer can be prevented from being damaged by direct friction, scratch and various corrosive substances, thereby not only solving the problems of color bleeding and fading in the printing of the film material, but also avoiding the safety and sanitation problems caused by the direct contact of the ink with food and medicines.

If the corona strength of the base film is required in the printing or composite process, the surfaces of the cellulose film layer 1 with the coating and the modified PLA film layer 2 can be subjected to corona treatment, so that the adhesive force of the printing ink or the adhesive of the printing layer 4 is enhanced.

The utility model relates to a degradable film accords with but not limited to following international authoritative degradation authentication:

● Germany DIN EN13432

● USA BPI ASTM D6400

● Belgium OK COMPOSTABLE at Belgium

● Australia ABAM.

The polyurethane adhesive used in the adhesive should have properties that meet, but are not limited to, the following health and safety regulations:

● Chinese food packaging material additive regulation GB9685-2008

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

● EU ROHS hazardous substance restriction directive

The utility model relates to a composite technology which is dry composite and solvent-free composite respectively.

When the composite membrane is prepared, one of the coating cellulose film layer and the modified PLA film layer can be set as a gluing surface, namely the first substrate, and the first substrate is attached to another material after being coated with the adhesive layer.

As shown in fig. 3 and 4, the composite process suitable for the composite film structure includes two processes: dry compounding and solvent-free compounding.

Dry type composite technology

The dry compounding process includes coating one layer of solvent adhesive on the first film with gravure screen roller, stoving and drying the solvent adhesive to eliminate solvent, and hot pressing the second film, the first film and the adhesive to form one integral.

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, and can be used for producing common composite films and 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, a dry composite preparation method of a high-transparency high-barrier fully biodegradable composite film material structure is provided, wherein a first substrate passes through a coating mechanism composed of a rubber disc 5, a scraper, a gravure roll 6 and a rubber press roll i 7, the first substrate is generally a cellulose film layer 1 with a coating layer, the surface of the first substrate is coated with a solvent type adhesive layer 3, the first substrate enters a drying tunnel 8 to dry the solvent type adhesive 3 layer to remove the solvent, the drying tunnel 8 is at a temperature of 40-60 ℃, then the first substrate enters a hot press mechanism composed of a heating steel roll 10 and a rubber press roll ii 9, a second substrate is pressed on the solvent type adhesive layer 3 to press the cellulose film layer 1 with the coating layer, the adhesive layer 3 and the modified PLA layer 2 together, the heating steel roll 10 is at a temperature of 40-60 ℃, the composite pressure of the hot press mechanism is required to be increased as much as possible without damaging the film, and finally a composite film i 13 is obtained through a cooling roll 11; and curing the composite film I13 to obtain a composite film structure.

Solvent-free compounding process

The solvent-free compounding method comprises the steps of firstly coating a solvent-free polyurethane adhesive on a first substrate by using a coating roller, wherein the viscosity of the solvent-free polyurethane adhesive is high at normal temperature, the viscosity is rapidly 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 under a hot pressing state, and the solvent-free polyurethane adhesive is coated (gummed) on the first substrateThe amount is 1-4g/m ² ) And finally, the second layer of film, the first layer of film and the adhesive are hot-pressed and compounded together, and the like, namely, one layer is compounded with another layer.

The adhesive of the solvent-free compounding method does not contain an organic solvent and does not need a drying device.

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 5, a scraper, a coating roller 12 and a rubber press roller i 7, under the belt of a guide roller, the first substrate surface coated with the adhesive layer 3 is sent to a hot-pressing mechanism composed of a heating steel roller 10 and a rubber press roller ii 9, the second substrate is hot-pressed on the adhesive layer 3, so that the coated cellulose film layer 1, the adhesive layer 3 and the PLA modified film layer 2 are mutually pressed together, the temperature of the heating steel roller 10 is between 40 and 60 ℃, the composite pressure of the hot-pressing mechanism is increased as much as possible without damaging the film, and finally, a composite film ii 14 is obtained through a cooling roller 10; and curing the composite film II 14 to obtain a composite film structure.

The adhesive layer 3 can bond the coated cellulose film layer 1 and the PLA modified film layer 2 together because when the adhesive layer 3 is respectively bonded with the base films, adhesive force is generated in the process of drying curing (with solvent polyurethane adhesive) or heating curing (without solvent polyurethane adhesive), namely, in the process of compounding, the adhesive layer 3 enters the coated cellulose film layer 1 and the modified PLA film layer 2 under the condition of pressure to form adhesive force between the two layers. The bonding effect can be affected by factors such as speed, blade distance, solvent formulation, pressure distribution, etc. during the compounding process.

The composite film I13 and the composite film II 14 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 selected to be placed in a constant temperature room with the temperature of 35-50 ℃ for more than 6 hours, and the temperature is increased to accelerate the speed of chemical reaction.

The curing reaction is beneficial to the curing of the adhesive layer 3, and is beneficial to accelerating the mutual reaction of-NCO groups in the adhesive layer 3 and active hydrogen groups on the surfaces of the coated cellulose film layer 1 and the modified PLA film layer 2. The adhesive layer 3 can be softened by heating, so that the wetting of the surfaces of the cellulose film layer 1 with the coating and the modified PLA film layer 2 is increased, the molecular motion is facilitated, the bonding force is improved, the subsequent processing of the product can be rapidly carried out, and the production period is shortened. Before the completion of the aging reaction, the peel strength of the composite film I13 and the composite film II 14 was changed, and it was a process of presenting increase-decay-stabilization. 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 can reach more than 1.5N-2N.

Claims

1. The utility model provides a high transparent high resistant full biodegradable composite film material structure who separates which characterized in that: the composite film structure comprises a coated cellulose film layer, a modified PLA film layer and an adhesive layer clamped between the coated cellulose film layer and the modified PLA film layer, wherein the coated cellulose film layer, the adhesive layer and the modified PLA film layer are combined together through a composite film forming technology.

2. The structure of the high-transparency high-barrier full-biodegradable composite film material as claimed in claim 1, wherein: the coated cellulose film layer comprises a natural cellulose film layer and PVDC coatings coated on the upper surface and the lower surface of the natural cellulose film layer.

3. The structure of the high-transparency high-barrier full-biodegradable composite film material as claimed in claim 1, wherein: the coated cellulose film layer comprises a natural cellulose film layer and aluminum oxide coatings coated on the upper surface and the lower surface of the natural cellulose film layer.

4. The structure of the high-transparency high-barrier full-biodegradable composite film material as claimed in claim 1, wherein: the coated cellulose film layer comprises a natural cellulose film layer and acrylic acid coatings coated on the upper surface and the lower surface of the natural cellulose film layer.

5. The structure of claim 1, wherein the structure is characterized in that: and the aluminum oxide coating is coated on the surface of the modified PLA film layer.

6. The structure of the high-transparency high-barrier full-biodegradable composite film material as claimed in claim 1, wherein: a printing layer is arranged between the cellulose film layer with the coating and the adhesive layer, and the printing layer is arranged on the inner surface of the cellulose film layer with the coating.