Anti-fog high-barrier matt film and preparation method thereof

Abstract

The invention belongs to the field of thin films, and relates to an anti-fog high-barrier matt film and a preparation method thereof. The anti-fog high-barrier matt film comprises an anti-fog barrier matt layer, a core layer and a bottom coating which are arranged in sequence, the anti-fog barrier matting layer is prepared from polypropylene random copolymer, 40 to 46 weight percent of high-density polyethylene, 4 to 10 weight percent of N-(n-alkyl) diethanolamine acrylic acid monoester grafted modified propylene-norbornene copolymer and 1 to 2 weight percent of maleic anhydride grafted homo-polypropylene; the core layer comprises homo-polypropylene; the bottom coating is prepared from an ethylene-octylene copolymer, 10 to 15 weight percent of a propylene-butylene copolymer and 2 to 5 weight percent of an alkyl maleate grafted modified ethylene-vinyl acetate copolymer. The anti-fog high-barrier matt film not only is favorable for improving the binding force between the film priming coat and the coated hot melt adhesive layer, but also has anti-fog and barrier properties, and can be suitable for a humid extreme environment.

Description

Technical Field

[0001] The present invention relates to the field of thin films, and particularly to an anti-fog high-barrier matte film and a preparation method thereof. Background Art

[0002] BOPP film is a packaging film that is first longitudinally stretched and then transversely stretched. Generally, it is a co-extruded composite structure of 3 to 5 layers. After the film is stretched multiple times, it exhibits good mechanical properties and optical properties. It has the advantages of light weight, good printing performance, and good moisture resistance. When traditional BOPP film is directly coated with EVA hot melt adhesive, the bonding force between EVA and the homopolymer PP of the BOPP film is poor. Therefore, generally, an AC agent (aqueous solution of high molecular weight polyethylene imine) is coated offline before coating with EVA. Then, EVA is coated. Since the organic solvents used in the AC agent coating stage are harmful to both the human body and the environment, and the process efficiency of offline coating and then laminating is relatively low, a BOPP film with a bottom coating has been developed on the market. One surface layer of the BOPP film with a bottom coating contains a bottom coating layer during extrusion, which can replace the traditional AC agent. When used downstream, EVA hot melt adhesive can be directly coated, reducing one process compared to offline coating and being more energy-saving and environmentally friendly.

[0003] However, currently on the market, due to poor barrier properties, the bottom coating layer of the film with a bottom coating generally has a problem of insufficient bonding force when compounded with the EVA coating layer. Moreover, in extremely humid environments, such as during the humid season, the anti-fog performance of the film also needs to be considered so that the pattern and text on the printed matter can be clearly seen after laminating the printed matter.

[0004] Regarding the anti-fog performance of the film, the prior art generally achieves it by adding anti-fog agents. Anti-fog agents are mainly divided into internal addition type and external coating type. The internal addition type anti-fog agent is mixed with PP resin during the film production process. Commonly used ones include polyol fatty acid esters, polyglycerol fatty acid esters, etc. These anti-fog agents can reduce the surface tension of the film surface, causing water vapor to form a uniform water film on the film surface instead of water droplets, thereby achieving the anti-fog effect. Since the anti-fog agent is essentially a surfactant, and the surfactant has a lubricating effect, when the content of the anti-fog agent added is relatively high during processing and mixing, it will cause the screw to slip, resulting in uneven dispersion of the anti-fog agent in the resin matrix. Although the external coating type anti-fog agent can be sprayed multiple times to make up for the defect of insufficient anti-fog life of the film prepared by the internal addition type anti-fog agent, the bonding force between the external coating type anti-fog agent and the substrate is weak. Therefore, its water resistance and resistance to scouring are poor, and the external coating type anti-fog agent must be evenly coated on the substrate surface to achieve continuous and stable anti-fog performance. However, whether it is internal coating or external addition of anti-fog agents, there is a problem of migration, which affects the aging of the anti-fog effect. Summary of the Invention

[0005] Based on this, the object of the present invention is to provide an anti-fog high-barrier matte film and a preparation method thereof, which are beneficial to improving the bonding strength between the bottom coating of the film and the coated hot-melt adhesive layer, having both anti-fog and barrier properties, and being applicable to extreme humid environments.

[0006] First aspect: An anti-fog high-barrier matte film, comprising an anti-fog barrier matte layer, a core layer and a bottom coating arranged in sequence; The anti-fog barrier matte layer comprises random copolymerized polypropylene, 40-46 wt% high-density polyethylene, 4-10 wt% N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer, and 1-2 wt% maleic anhydride grafted homopolypropylene; wherein, the grafting rate of N-(n-alkyl) diethanolamine acrylate in the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer is 1-2.5%, and n is any integer from 14 to 18; The core layer comprises homopolypropylene; The bottom coating comprises ethylene-octene copolymer, 10-15 wt% propylene-butene copolymer, and 2-5 wt% alkyl maleate graft-modified ethylene-vinyl acetate copolymer; wherein, the grafting rate of alkyl maleate in the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 12-30%.

[0007] For the anti-fog barrier matte film of the present invention, on the one hand, by adding N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer (wherein N is read as "nitrogen" and n represents the alkyl chain length) to the anti-fog barrier matte layer, the film not only has good anti-fog performance but also has a certain barrier property, and the improvement of the barrier property is beneficial to improving the bonding strength between the bottom coating of the film and the hot-melt adhesive in a humid environment; on the other hand, adding alkyl maleate graft-modified ethylene-vinyl acetate copolymer to the bottom coating is beneficial to further improving the bonding strength between the bottom coating of the film and the hot-melt adhesive layer. Under the synergistic effect of the differential functions of the anti-fog barrier matte layer and the bottom coating, the bonding strength between the bottom coating of the film and the hot-melt adhesive in a humid environment is effectively enhanced.

[0008] The inventors of the present application found in experiments that the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer has certain anti-fog properties. The N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer is oriented, and its hydrophilic branched-chain segments tend to be away from the low-polarity resin matrix and towards the outside of the film, forming a hydrophilic layer on the film surface. The hydrophobic main-chain segments tend to face the core layer. In this way, water droplets can form a uniform, transparent and relatively thin water film on the surface of the film, which eliminates the influence of light diffuse reflection caused by more dispersed water droplets, thus not affecting the light transmittance of the film and achieving an anti-fog effect. The main-chain segment of the propylene-norbornene copolymer has a cyclic structure, which can play a certain barrier role and is conducive to reducing the migration of water in the water film into the film interior. Moreover, it has good melt fluidity, which is not only conducive to ensuring the uniformity of the matting effect of the matting layer, but also conducive to the uniform roughening of the surface of the anti-fog barrier matting layer, improving the problem of adhesion between the anti-fog barrier matting layer and the base coating of the matting film itself, and improving the smoothness of the winding and unwinding of the film during the manufacturing process.

[0009] To endow the film with appropriate anti-fog and barrier properties, the present invention adds 4-10 wt% of the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer to the anti-fog barrier matting layer. If the addition amount of the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer is too low, the anti-fog performance of the film cannot be effectively improved, and the barrier performance cannot be enhanced to synergistically improve the bonding strength between the base coating and the hot melt adhesive layer in a humid environment. If the addition amount is too high, it is not conducive to its dispersion between the anti-fog barrier matting layers, and the compatibility becomes poor, resulting in too large a viscosity difference from the core layer and causing the thick sheet to show an "incompatible state", so that a film with uniform thickness and gloss cannot be obtained, which is not conducive to the biaxial stretching of the film and further cannot be continuously produced normally. Further, the inventors control the grafting rate of N-(n-alkyl) diethanolamine acrylate in the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer at 1-2.5%. If the grafting rate is too low, there are too few hydrophilic groups and an effective anti-fog effect cannot be achieved. If the grafting rate is too high, the intermolecular forces such as intermolecular hydrogen bonds in the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer are too strong, forming a physical crosslinked structure, resulting in too poor compatibility with other components of the matting layer to be uniformly dispersed in the matting layer, and it is also not conducive to biaxial stretching.

[0010] In addition, the alkyl long chain of the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer has a large steric hindrance, which also restricts the migration of water molecules into the interior of the film to a certain extent. To enable the anti-fog barrier layer of the film to have appropriate barrier properties and cooperate with the cyclic structure of norbornene to play a better barrier role, the inventors controlled the alkyl chain length between 14 and 18 (i.e., n is any integer between 14 and 18). If the alkyl chain is too long, it will cause too large steric hindrance, which is not conducive to grafting N-(n-alkyl) diethanolamine acrylate onto the propylene-norbornene copolymer chain to obtain a graft copolymer within a suitable grafting rate range. If the alkyl chain is too short, it cannot effectively cooperate with the propylene-norbornene copolymer to achieve the purpose of enhancing the barrier effect. Preferably, the alkyl is a normal alkyl.

[0011] The present invention also adds 1-2 wt% of maleic anhydride grafted homopolypropylene to the anti-fog barrier and matting layer, so that the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer is evenly dispersed in the anti-fog barrier and matting layer, and at the same time enhances the bonding force between the anti-fog barrier and matting layer with a relatively large polarity and the core layer, ensuring no delamination during production and use.

[0012] In order to effectively enhance the bonding strength between the thin film bottom coating and the hot melt adhesive in a humid environment, the present invention adds 2-5 wt% of alkyl maleate graft-modified ethylene-vinyl acetate copolymer to the bottom coating. The content of polar ester groups in the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is higher than that in the ethylene-vinyl acetate copolymer. On the one hand, it makes the bonding between the bottom coating and the hot melt adhesive layer firmer. On the other hand, it synergizes with the barrier effect of the anti-fog barrier and matting layer, making it more suitable for enhancing the bonding strength with the hot melt adhesive layer in a humid environment, which is beneficial to ensuring the laminating quality of printed materials. If the content of the alkyl maleate graft-modified ethylene-vinyl acetate copolymer in the bottom coating is too high, it will cause the bottom coating to be too sticky, which is not conducive to the smooth unwinding and rewinding of the thin film, and will also cause too large a polarity difference between the bottom coating and the core layer, resulting in delamination during the biaxial stretching process; if the content is too low, the bonding strength between the bottom coating and the hot melt adhesive layer cannot be effectively enhanced, which is not conducive to the application of the thin film in a highly humid environment. In order to make the bottom coating and the hot melt adhesive layer have an appropriate adhesive force in a humid environment, the inventor also controls the grafting rate of the alkyl maleate of the alkyl maleate graft-modified ethylene-vinyl acetate copolymer at 12-30%. If the grafting rate is too high, the thermal stability of the alkyl maleate graft-modified ethylene-vinyl acetate copolymer itself will decrease, and thermal decomposition may occur at the production process temperature of the present invention, affecting the appearance quality of the thin film and the stability of production; if the grafting rate is too low, the content of polar ester groups in the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is low, and it cannot synergize with the anti-fog barrier and matting layer to improve the bonding strength between the bottom coating and the hot melt adhesive layer in a humid environment. Under the differential functional synergy of the anti-fog barrier and matting layer and the bottom coating, the bonding strength between the thin film bottom coating and the hot melt adhesive in a humid environment is effectively enhanced.

[0013] In the present invention, the bottom coating of the thin film comprises 10-15 wt% of propylene-butene copolymer, which is used to improve the interfacial compatibility between the bottom coating and the core layer. If the addition amount is <10 wt%, the interfacial bonding strength between the bottom coating and the core layer is relatively low, and the bonding strength between the two layers cannot be effectively improved. If the addition amount is >15 wt%, the compatibility between the bottom coating and the EVA hot melt adhesive layer is poor, which is not conducive to the bonding between the bottom coating and the EVA hot melt adhesive layer.

[0014] The anti-fog barrier and matting film described in the present invention belongs to a biaxially oriented polypropylene film, which itself contains a bottom coating and does not require secondary coating of a primer during use, saving energy and the environment. It not only has good anti-fog performance, and the pattern and text on the printed matter can still be clearly seen even when it encounters water after laminating the printed matter, but also has a certain barrier property. Under the synergistic effect of the differential functions of the anti-fog barrier and matting layer and the bottom coating of the film, it is beneficial to improve the bonding force between the bottom coating of the film and the hot melt adhesive layer, thereby enhancing the composite fastness between the film and the printed matter, and can be applied to some humid extreme environments. In addition, by synergistically utilizing the differential functions of the anti-fog barrier and matting layer and the bottom coating, the film does not stick to the roller smoothly during the biaxial stretching production process, and the film is smoothly unwound and rewound during the film production and application processes.

[0015] As a preferred solution, at 230 °C and a load of 2.16 kg, the melt index of the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer is 5-10 g / 10 min; the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer is obtained by graft-modifying a propylene-norbornene copolymer with N-(n-alkyl) diethanolamine acrylate, and the molar content of norbornene in the propylene-norbornene copolymer is 25-28%.

[0016] Controlling the melt index of the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer to be 5-10 g / 10 min is beneficial to its melt matching with other components of the anti-fog barrier and matting layer, obtaining a suitable thick sheet for biaxial stretching, and ensuring the smoothness of the biaxial stretching process. The inventor also controls the content of norbornene to make the anti-fog barrier and matting layer have a certain stiffness during the production and manufacturing process, reducing the adhesion force between the inner and outer layers of the film (i.e., between the bottom coating and the anti-fog barrier and matting layer), which is beneficial to ensuring the smoothness of the film production process and the smooth unwinding and rewinding.

[0017] As a preferred solution, at 230 °C and a load of 2.16 kg, the melt index of the random copolymer polypropylene is 6-10 g / 10 min; at 190 °C and a load of 2.16 kg, the melt index of the high-density polyethylene is 9-20 g / 10 min; the random copolymer polypropylene is selected from one or two of ethylene-propylene copolymer polypropylene or ethylene-propylene-butene copolymer polypropylene. Selecting the random copolymer polypropylene and high-density polyethylene within the above melt index range makes the anti-fog barrier and matting layer have appropriate melt fluidity, improves the matching of the overall melt flow, and is beneficial to obtaining a film with relatively excellent overall matting effect.

[0018] As a preferred embodiment, the isotacticity of the homopolypropylene is 90-99%, and at 230 °C under a load of 2.16 kg, the melt index is 3.5-3.8 g / 10 min, which is beneficial to ensuring the overall mechanical properties of the film and is also beneficial to improving the compatibility between the homopolypropylene in the core layer and the components of the bottom coating to avoid the occurrence of interlayer peeling.

[0019] As a preferred embodiment, at 190 °C under a load of 2.16 kg, the melt index of the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 26-28 g / 10 min; the melting point of the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 80-90 °C; the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is modified from an alkyl maleate grafted ethylene-vinyl acetate copolymer, and the melt index of the ethylene-vinyl acetate copolymer is 20-25 g / 10 min. Controlling the melt index of the alkyl maleate graft-modified ethylene-vinyl acetate copolymer to be 26-28 g / 10 min and the melting point to be 80-90 °C is beneficial to improving the compatibility of the alkyl maleate graft-modified ethylene-vinyl acetate copolymer with other components of the bottom coating and enhancing the bonding strength between the bottom coating and the hot melt adhesive layer.

[0020] As a preferred embodiment, the alkyl maleate in the alkyl maleate graft-modified ethylene-vinyl acetate copolymer has a double ester group structure and belongs to a dialkyl maleate. The alkyl maleate is any one of dioctyl maleate or dibutyl maleate. In a specific embodiment, the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is obtained by a radical polymerization reaction of an alkyl maleate and an ethylene-vinyl acetate copolymer, and the alkyl maleate is obtained by an esterification reaction of an alkyl alcohol and maleic acid. The alkyl maleate is preferably any one of dioctyl maleate or dibutyl maleate, which is beneficial to further improving the compatibility of the alkyl maleate graft-modified ethylene-vinyl acetate copolymer with other components of the bottom coating.

[0021] As a preferred solution, the melting point of the ethylene-octene copolymer is 75-95 °C, and the melting point of the propylene-butene copolymer is 80-95 °C. This is beneficial to avoid the phenomenon of sticking to the roller during the production process, and improve the compatibility and interlayer bonding force between the bottom coating and the subsequently coated EVA hot melt adhesive. If the melting point of the ethylene-octene copolymer is <75 °C, the bottom coating is prone to sticking to the roller during longitudinal stretching, which easily causes defect points on the film surface, and is prone to adhesion or even unable to be unwound under a large tension during winding; if the melting point of the ethylene-octene copolymer is >95 °C, the compatibility and interlayer bonding force between the bottom coating and the subsequently coated EVA hot melt adhesive decrease; if the melting point of the propylene-butene copolymer is <80 °C, the bottom coating is prone to sticking to the roller during longitudinal stretching; if the melting point of the propylene-butene copolymer is >95 °C, the compatibility and interlayer bonding force between the bottom coating and the subsequently coated EVA hot melt adhesive decrease. In addition, the melting point of the propylene-butene copolymer and the melting point of the ethylene-octene copolymer should be similar. If the melting point difference is too large, it is not conducive to the bonding between the bottom coating and the subsequently coated EVA hot melt adhesive layer.

[0022] As a preferred solution, the bottom coating further includes 0.5-1 wt% of a polyorganosiloxane elastomer, and the particle size D90 of the polyorganosiloxane elastomer is 3-5 μm.

[0023] Adding a polyorganosiloxane elastomer with a suitable particle size to the bottom coating is beneficial to improve the anti-adhesion performance of the bottom coating, avoid adhesion caused by the contact between the inner and outer layers (i.e., between the bottom coating and the anti-fog barrier and matting layer) during winding of the rolled film, and make the winding and unwinding smoother. In addition, in order to reduce the thermal oxygen degradation or further cross-linking of the low-melting polyolefin resin in the bottom coating during high-temperature extrusion, and reduce the quality problem of uneven film stretching, an antioxidant can also be added to the bottom coating.

[0024] Second aspect: A method for preparing an anti-fog high-barrier and matting film as described in the first aspect, comprising the following steps: Put the component raw materials of the anti-fog barrier and matting layer, the core layer, and the bottom coating into the batching unit respectively, meter them, and then co-extrude them through an extruder. After passing through the runner distributor, they converge in a three-layer die head, and then form a thick sheet after cooling by a chill roll. The thick sheet is biaxially stretched by a stretching roll to form a film. The film is cooled, and at the same time, the thickness is controlled by a trimming machine, and then corona and / or flame treatment is carried out to obtain the anti-fog high-barrier and matting film.

[0025] As a preferred solution, the surface of the bottom coating feeding trough of the extruder and the surface of the stretching rollers used in biaxial stretching are provided with Teflon coatings. The Teflon coatings are beneficial to avoid the adhesion of the alkyl maleate graft-modified ethylene-vinyl acetate copolymer in the bottom coating to other components of the bottom coating during the extrusion and stretching processes, thereby avoiding affecting the smoothness of processing and the integrity of the film surface. Moreover, the appropriate viscosity of the alkyl maleate graft-modified ethylene-vinyl acetate copolymer can avoid problems such as slipping and abrasion of the film on the stretching rollers provided with Teflon coatings. Detailed implementation mode

[0026] The present invention will be described more comprehensively below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. For the experimental methods without specific conditions in the following examples or comparative examples, they are generally carried out according to the conventional conditions in the art or according to the conditions recommended by the manufacturer; the raw materials, reagents, etc. used, unless otherwise specified, are all raw materials and reagents that can be obtained from commercial channels such as conventional markets.

[0027] As an implementation mode, this embodiment provides an anti-fog high-barrier matte film, which includes an anti-fog barrier matte layer, a core layer, and a bottom coating arranged in sequence; The anti-fog barrier matte layer includes random copolymer polypropylene (random copolymer PP), 40-46 wt% high-density polyethylene (HDPE), 4-10 wt% N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer, and 1-2 wt% maleic anhydride grafted homopolypropylene; wherein, the grafting rate of N-(n-alkyl) diethanolamine acrylate in the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer is 1-2.5%, n is any integer from 14 to 18, and the alkyl group is a normal alkyl group; The core layer includes homopolypropylene; The bottom coating includes ethylene-octene copolymer, 10-15 wt% propylene-butene copolymer, and 2-5 wt% alkyl maleate graft-modified ethylene-vinyl acetate copolymer; wherein, the grafting rate of the alkyl maleate in the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 12-30%.

[0028] Furthermore, at 230 °C and a load of 2.16 kg, the melt index of the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer is 5-10 g / 10 min; the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer is modified by grafting N-(n-alkyl) diethanolamine acrylate onto a propylene-norbornene copolymer, and the molar content of norbornene in the propylene-norbornene copolymer is 25-28%.

[0029] Further, at 230°C and under a load of 2.16 kg, the melt index of the random copolymer polypropylene is 6-10 g / 10 min; at 190°C and under a load of 2.16 kg, the melt index of the high-density polyethylene is 9-20 g / 10 min; the random copolymer polypropylene is selected from one or two of ethylene-propylene copolymer polypropylene or ethylene-propylene-butene copolymer polypropylene.

[0030] Further, the isotacticity of the homopolymer polypropylene is 90-99%, and at 230°C and under a load of 2.16 kg, the melt index is 3.5-3.8 g / 10 min.

[0031] Further, the core layer further comprises 1-2 wt% of an antistatic agent.

[0032] Further, at 190°C and under a load of 2.16 kg, the melt index of the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 26-28 g / 10 min; the melting point of the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 80-90°C; the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is obtained by modifying an ethylene-vinyl acetate copolymer with an alkyl maleate, and the melt index of the ethylene-vinyl acetate copolymer is 20-25 g / 10 min.

[0033] Further, the alkyl maleate in the alkyl maleate graft-modified ethylene-vinyl acetate copolymer has a double ester group structure and belongs to a dialkyl maleate, and the alkyl maleate is any one of dioctyl maleate or dibutyl maleate.

[0034] Further, the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is obtained by radical polymerization of an alkyl maleate and an ethylene-vinyl acetate copolymer, and the alkyl maleate is obtained by esterification of an alkyl alcohol and maleic anhydride.

[0035] Further, the melting point of the ethylene-octene copolymer is 75-95°C, and the melting point of the propylene-butene copolymer is 80-95°C.

[0036] Further, the bottom coating further comprises 0.5-1 wt% of a polyorganosiloxane elastomer, and the particle size D90 of the polyorganosiloxane elastomer is 3-5 μm.

[0037] Further, the bottom coating further comprises 0.1-0.3 wt% of an antioxidant, and the antioxidant is compounded from antioxidant 1010 and antioxidant 168 in a mass ratio of 1:2.

[0038] Further, the total thickness of the prepared film is 14-25 μm, including an anti-fog barrier and matting layer of 1.6-2.0 μm, a core layer, and a bottom coating of 1-2 μm.

[0039] The embodiment of the present invention also provides a method for preparing an anti-fog high-barrier matte film, which includes the following steps: Put the component raw materials of the anti-fog barrier matte layer, the core layer, and the bottom coating into the batching unit respectively. After metering, they are co-extruded by an extruder, converged in a three-layer die head via a runner distributor, and then formed into a thick sheet after cooling by a chill roll. The thick sheet is biaxially stretched by a stretching roll to form a film. The film is cooled, and at the same time, the thickness is controlled by a trimming machine. After corona and / or flame treatment, an anti-fog high-barrier matte film is obtained.

[0040] Further, a Teflon coating is provided on the surface of the bottom coating feeding groove of the extruder and on the surface of the stretching roll used for biaxial stretching.

[0041] As shown in Table 1, it is a summary table of the component and its content of each layer of Examples 1-3 and Comparative Examples 1-10.

[0042] Some raw materials and their parameters are as follows: In the anti-fog barrier matte layer, the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer is modified by grafting N-(n-alkyl) diethanolamine acrylate after plasma treatment of the propylene-norbornene copolymer. At 230 °C and a load of 2.16 kg, the melt index is 8 g / 10 min, and n-alkyl is a normal alkyl group; the molar content of norbornene in the propylene-norbornene copolymer is 26%.

[0043] The random copolymerized polypropylene is ethylene-propylene copolymerized polypropylene. At 230 °C and a load of 2.16 kg, the melt index is 8 g / 10 min; at 190 °C and a load of 2.16 kg, the melt index of high-density polyethylene is 11 g / 10 min.

[0044] In the core layer, the selected antistatic agent is glycerol monostearate.

[0045] In the bottom coating, the melt index of the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 26 g / 10 min, the melting point is 85 °C, and the alkyl maleate is dioctyl maleate; the melt index of the ethylene-vinyl acetate copolymer is 20 g / 10 min; the melting point of the ethylene-octene copolymer is 85 °C, and the melt index is 6.5 g / 10 min; the melting point of the propylene-butene copolymer is 85 °C, and the melt index is 7 g / 10 min; the particle size D90 of the polyorganosiloxane elastomer is 5 μm; the antioxidant is compounded by antioxidant 1010 and antioxidant 168 in a mass ratio of 1:2.

[0046] Table 1 - Component composition of each layer of each example and comparative example

[0047] Example 1 This example provides an anti-fog high-barrier matte film with a total thickness of 18 μm, including a 2.0-μm anti-fog barrier matte layer, a 14.2-μm core layer, and a 1.8-μm bottom coating layer.

[0048] The anti-fog barrier matte layer includes 40 wt% high-density polyethylene, 4 wt% N-tetradecyldiethanolamine acrylate graft-modified propylene-norbornene copolymer, 1 wt% maleic anhydride grafted homopolypropylene, and 55 wt% random copolymer polypropylene. Among them, the grafting rate of N-tetradecyldiethanolamine acrylate in the N-tetradecyldiethanolamine acrylate graft-modified propylene-norbornene copolymer is 1 wt%.

[0049] The core layer includes 99 wt% isotactic polypropylene with an isotacticity of 95% and a melt index of 3.6 g / 10 min, and 1 wt% antistatic agent.

[0050] The bottom coating layer includes 10 wt% propylene-butene copolymer, 2 wt% alkyl maleate graft-modified ethylene-vinyl acetate copolymer, 0.5 wt% polyorganosiloxane elastomer, 0.1 wt% antioxidant, and 87.4 wt% ethylene-octene copolymer. Among them, the grafting rate of alkyl maleate in the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 12 wt%.

[0051] This example also provides a preparation method for the anti-fog high-barrier matte film, including the following steps: Put the component raw materials of the anti-fog barrier matte layer, core layer, and bottom coating layer into the batching unit respectively to obtain the anti-fog barrier matte layer resin, core layer resin, and bottom coating layer resin.

[0052] Transport each layer of resin to three screw extruders through a batcher (where the bottom coating layer and the matte layer are single-screw extruders, the core layer is a twin-screw extruder, the extrusion temperature of the bottom coating layer is 235 °C, the extrusion temperature of the anti-fog barrier matte layer is set at 245 °C, and the extrusion temperature of the core layer is 250 °C). After the melts of the three extruders are metered by melt metering pumps, they converge into a thick sheet in a T-die through a long and narrow flow channel. The thick sheet is cooled by a chill roll and enters a chill water tank, then enters a blow-off chamber and then enters the longitudinal stretching area for longitudinal stretching (bottom coating layer: the preheating zone temperature is 70 °C, the stretching zone temperature is 60 °C, and the shaping zone temperature is 65 °C; anti-fog barrier matte layer: the preheating zone temperature is 135 °C, the stretching zone temperature is 130 °C, and the shaping zone temperature is 130 °C; the longitudinal stretching ratio is 5 times). Subsequently, it enters the transverse stretching area for transverse stretching (the stretching temperature is 160 °C, and the transverse stretching ratio is 8 times). Then, after shaping, trimming and corona treatment are carried out, and then it is wound onto an aging rack for treatment. After the treatment is completed, it is slit and packaged into finished products.

[0053] Example 2 This example provides an anti-fog high-barrier matte film with a total thickness of 18 μm, including a 2.0-μm anti-fog barrier matte layer, a 14.2-μm core layer, and a 1.8-μm bottom coating layer.

[0054] The anti-fog barrier matte layer includes 43 wt% high-density polyethylene, 7 wt% N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer, 1.2 wt% maleic anhydride grafted homopolypropylene, and 48.8 wt% random copolymer polypropylene. Among them, the grafting rate of N-hexadecyl diethanolamine acrylate in the N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer is 1.5 wt%.

[0055] The core layer includes 99 wt% isotactic polypropylene with an isotacticity of 95% and a melt index of 3.6 g / 10 min, and 1 wt% antistatic agent.

[0056] The bottom coating layer includes 12 wt% propylene-butene copolymer, 3.5 wt% alkyl maleate graft-modified ethylene-vinyl acetate copolymer, 0.5 wt% polyorganosiloxane elastomer, 0.1 wt% antioxidant, and 83.9 wt% ethylene-octene copolymer. Among them, the grafting rate of alkyl maleate in the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 20 wt%.

[0057] The preparation method of the anti-fog high-barrier matte film in this example is the same as that in Example 1.

[0058] Example 3 This example provides an anti-fog high-barrier matte film with a total thickness of 18 μm, including a 2.0-μm anti-fog barrier matte layer, a 14.2-μm core layer, and a 1.8-μm bottom coating layer.

[0059] The anti-fog barrier matte layer includes 46 wt% high-density polyethylene, 10 wt% N-octadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer, 1.5 wt% maleic anhydride grafted homopolypropylene, and 42.5 wt% random copolymer polypropylene. Among them, the grafting rate of N-octadecyl diethanolamine acrylate in the N-octadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer is 2.5 wt%.

[0060] The core layer includes 99 wt% isotactic polypropylene with an isotacticity of 95% and a melt index of 3.6 g / 10 min, and 1 wt% antistatic agent.

[0061] The primer coat comprises 15 wt% of an ethylene-butene copolymer, 5 wt% of an alkyl maleate graft-modified ethylene-vinyl acetate copolymer, 0.5 wt% of a polyorganosiloxane elastomer, 0.1 wt% of an antioxidant, and 79.4 wt% of an ethylene-octene copolymer. Among them, the grafting rate of the alkyl maleate in the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 30 wt%.

[0062] The preparation method of the anti-fog high-barrier matte film in this example is the same as that in Example 1.

[0063] Comparative Example 1 This comparative example provides an anti-fog high-barrier matte film with a total thickness of 18 μm, including a 2.0-μm anti-fog barrier matte layer, a 14.2-μm core layer, and a 1.8-μm primer coat.

[0064] The anti-fog barrier matte layer comprises 43 wt% of high-density polyethylene, 1 wt% of an N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer, 1.2 wt% of maleic anhydride grafted homopolypropylene, and 54.8 wt% of random copolymer polypropylene. Among them, the grafting rate of N-hexadecyl diethanolamine acrylate in the N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer is 1.5 wt%.

[0065] The core layer comprises 99 wt% of isotactic polypropylene with an isotacticity of 95% and a melt index of 3.6 g / 10 min, and 1 wt% of an antistatic agent.

[0066] The primer coat comprises 12 wt% of an ethylene-butene copolymer, 3.5 wt% of an alkyl maleate graft-modified ethylene-vinyl acetate copolymer, 0.5 wt% of a polyorganosiloxane elastomer, 0.1 wt% of an antioxidant, and 83.9 wt% of an ethylene-octene copolymer. Among them, the grafting rate of the alkyl maleate in the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 20 wt%.

[0067] The preparation method of the anti-fog high-barrier matte film in this comparative example is the same as that in Example 1.

[0068] Comparative Example 2 This comparative example provides an anti-fog high-barrier matte film with a total thickness of 18 μm, including a 2.0-μm anti-fog barrier matte layer, a 14.2-μm core layer, and a 1.8-μm primer coat.

[0069] The anti-fog barrier and matting layer comprises 43 wt% high-density polyethylene, 15 wt% N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer, 1.2 wt% maleic anhydride grafted isotactic polypropylene, and 40.8 wt% random copolymer polypropylene. Among them, the grafting rate of N-hexadecyl diethanolamine acrylate in the N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer is 1.5 wt%.

[0070] The core layer comprises 99 wt% isotactic polypropylene with an isotacticity of 95% and a melt index of 3.6 g / 10 min, and 1 wt% antistatic agent.

[0071] The bottom coating layer comprises 12 wt% propylene-butene copolymer, 3.5 wt% alkyl maleate graft-modified ethylene-vinyl acetate copolymer, 0.5 wt% polyorganosiloxane elastomer, 0.1 wt% antioxidant, and 83.9 wt% ethylene-octene copolymer. Among them, the grafting rate of alkyl maleate in the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 20 wt%.

[0072] The preparation method of the anti-fog high-barrier and matting film in this comparative example is the same as that in Example 1.

[0073] Comparative Example 3 This comparative example provides an anti-fog high-barrier and matting film with a total thickness of 18 μm, including a 2.0-μm anti-fog barrier and matting layer, a 14.2-μm core layer, and a 1.8-μm bottom coating layer.

[0074] The anti-fog barrier and matting layer comprises 43 wt% high-density polyethylene, 7 wt% N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer, 1.2 wt% maleic anhydride grafted isotactic polypropylene, and 48.8 wt% random copolymer polypropylene. Among them, the grafting rate of N-hexadecyl diethanolamine acrylate in the N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer is 0.5 wt%.

[0075] The core layer comprises 99 wt% isotactic polypropylene with an isotacticity of 95% and a melt index of 3.6 g / 10 min, and 1 wt% antistatic agent.

[0076] The bottom coating layer comprises 12 wt% propylene-butene copolymer, 3.5 wt% alkyl maleate graft-modified ethylene-vinyl acetate copolymer, 0.5 wt% polyorganosiloxane elastomer, 0.1 wt% antioxidant, and 83.9 wt% ethylene-octene copolymer. Among them, the grafting rate of alkyl maleate in the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 20 wt%.

[0077] The preparation method of the anti-fog high-barrier matte film in this comparative example is the same as that in Example 1.

[0078] Comparative Example 4 This comparative example provides an anti-fog high-barrier matte film with a total thickness of 18 μm, including a 2.0-μm anti-fog barrier matte layer, a 14.2-μm core layer, and a 1.8-μm bottom coating.

[0079] The anti-fog barrier matte layer includes 43 wt% high-density polyethylene, 7 wt% N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer, 1.2 wt% maleic anhydride grafted homopolypropylene, and 48.8 wt% random copolymerized polypropylene. Among them, the grafting rate of N-hexadecyl diethanolamine acrylate in the N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer is 4 wt%.

[0080] The core layer includes 99 wt% isotactic polypropylene with an isotacticity of 95% and a melt index of 3.6 g / 10 min, and 1 wt% antistatic agent.

[0081] The bottom coating includes 12 wt% propylene-butene copolymer, 3.5 wt% alkyl maleate graft-modified ethylene-vinyl acetate copolymer, 0.5 wt% polyorganosiloxane elastomer, 0.1 wt% antioxidant, and 83.9 wt% ethylene-octene copolymer. Among them, the grafting rate of alkyl maleate in the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 20 wt%.

[0082] The preparation method of the anti-fog high-barrier matte film in this comparative example is the same as that in Example 1.

[0083] Comparative Example 5 This comparative example provides an anti-fog high-barrier matte film with a total thickness of 18 μm, including a 2.0-μm anti-fog barrier matte layer, a 14.2-μm core layer, and a 1.8-μm bottom coating.

[0084] The anti-fog barrier matte layer includes 43 wt% high-density polyethylene, 7 wt% N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer, 1.2 wt% maleic anhydride grafted homopolypropylene, and 48.8 wt% random copolymerized polypropylene. Among them, the grafting rate of N-hexadecyl diethanolamine acrylate in the N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer is 1.5 wt%.

[0085] The core layer includes 99 wt% isotactic polypropylene with an isotacticity of 95% and a melt index of 3.6 g / 10 min, and 1 wt% antistatic agent.

[0086] The bottom coating comprises 12 wt% of propylene-butene copolymer, 0.5 wt% of polyorganosiloxane elastomer, 0.1 wt% of antioxidant, and 87.4 wt% of ethylene-octene copolymer.

[0087] The preparation method of the anti-fog high-barrier matte film of this comparative example is the same as that of Example 1.

[0088] Comparative Example 6 This comparative example provides an anti-fog high-barrier matte film with a total thickness of 18 μm, including a 2.0-μm anti-fog barrier matte layer, a 14.2-μm core layer, and a 1.8-μm bottom coating.

[0089] The anti-fog barrier matte layer comprises 43 wt% of high-density polyethylene, 7 wt% of N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer, 1.2 wt% of maleic anhydride grafted homopolypropylene, and 48.8 wt% of random copolymer polypropylene. Among them, the grafting rate of N-hexadecyl diethanolamine acrylate in the N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer is 1.5 wt%.

[0090] The core layer comprises 99 wt% of isotactic polypropylene with an isotacticity of 95% and a melt index of 3.6 g / 10 min, and 1 wt% of antistatic agent.

[0091] The bottom coating comprises 12 wt% of propylene-butene copolymer, 8 wt% of alkyl maleate graft-modified ethylene-vinyl acetate copolymer, 0.5 wt% of polyorganosiloxane elastomer, 0.1 wt% of antioxidant, and 79.4 wt% of ethylene-octene copolymer. Among them, the grafting rate of alkyl maleate in the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 20 wt%.

[0092] The preparation method of the anti-fog high-barrier matte film of this comparative example is the same as that of Example 1.

[0093] Comparative Example 7 This comparative example provides an anti-fog high-barrier matte film with a total thickness of 18 μm, including a 2.0-μm anti-fog barrier matte layer, a 14.2-μm core layer, and a 1.8-μm bottom coating.

[0094] The anti-fog barrier matte layer comprises 43 wt% of high-density polyethylene, 7 wt% of N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer, 1.2 wt% of maleic anhydride grafted homopolypropylene, and 48.8 wt% of random copolymer polypropylene. Among them, the grafting rate of N-hexadecyl diethanolamine acrylate in the N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer is 1.5 wt%.

[0095] The core layer comprises 99 wt% of isotactic polypropylene with an isotacticity of 95% and a melt index of 3.6 g / 10 min, and 1 wt% of an antistatic agent.

[0096] The bottom coating comprises 12 wt% of an ethylene - butene copolymer, 3.5 wt% of an alkyl maleate - grafted ethylene - vinyl acetate copolymer, 0.5 wt% of a polyorganosiloxane elastomer, 0.1 wt% of an antioxidant, and 83.9 wt% of an ethylene - octene copolymer. Among them, the grafting rate of the alkyl maleate in the alkyl maleate - grafted ethylene - vinyl acetate copolymer is 5 wt%.

[0097] The preparation method of the anti - fog high - barrier matte film of this comparative example is the same as that of Example 1.

[0098] Comparative Example 8 This comparative example provides an anti - fog high - barrier matte film with a total thickness of 18 μm, comprising a 2.0 - μm anti - fog barrier matte layer, a 14.2 - μm core layer, and a 1.8 - μm bottom coating.

[0099] The anti - fog barrier matte layer comprises 43 wt% of high - density polyethylene, 7 wt% of N - hexadecyl diethanolamine acrylate - grafted propylene - norbornene copolymer, 1.2 wt% of maleic anhydride - grafted isotactic polypropylene, and 48.8 wt% of random copolymer polypropylene. Among them, the grafting rate of N - hexadecyl diethanolamine acrylate in the N - hexadecyl diethanolamine acrylate - grafted propylene - norbornene copolymer is 1.5 wt%.

[0100] The core layer comprises 99 wt% of isotactic polypropylene with an isotacticity of 95% and a melt index of 3.6 g / 10 min, and 1 wt% of an antistatic agent.

[0101] The bottom coating comprises 12 wt% of an ethylene - butene copolymer, 3.5 wt% of an alkyl maleate - grafted ethylene - vinyl acetate copolymer, 0.5 wt% of a polyorganosiloxane elastomer, 0.1 wt% of an antioxidant, and 83.9 wt% of an ethylene - octene copolymer. Among them, the grafting rate of the alkyl maleate in the alkyl maleate - grafted ethylene - vinyl acetate copolymer is 40 wt%.

[0102] The preparation method of the anti - fog high - barrier matte film of this comparative example is the same as that of Example 1.

[0103] Comparative Example 9 This comparative example provides an anti - fog high - barrier matte film with a total thickness of 18 μm, comprising a 2.0 - μm anti - fog barrier matte layer, a 14.2 - μm core layer, and a 1.8 - μm bottom coating.

[0104] The anti-fog barrier and matting layer comprises 43 wt% of high-density polyethylene, 7 wt% of N-n-octyldiethanolamine acrylate graft-modified propylene-norbornene copolymer, 1.2 wt% of maleic anhydride grafted isotactic polypropylene, and 48.8 wt% of random copolymerized polypropylene. Among them, the grafting rate of N-n-octyldiethanolamine acrylate in the N-n-octyldiethanolamine acrylate graft-modified propylene-norbornene copolymer is 1.5 wt%.

[0105] The core layer comprises 99 wt% of isotactic polypropylene with an isotacticity of 95% and a melt index of 3.6 g / 10 min, and 1 wt% of an antistatic agent.

[0106] The bottom coating layer comprises 12 wt% of propylene-butene copolymer, 3.5 wt% of alkyl maleate graft-modified ethylene-vinyl acetate copolymer, 0.5 wt% of polyorganosiloxane elastomer, 0.1 wt% of antioxidant, and 83.9 wt% of ethylene-octene copolymer. Among them, the grafting rate of alkyl maleate in the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 20 wt%.

[0107] The preparation method of the anti-fog high-barrier and matting film of this comparative example is the same as that of Example 1.

[0108] Comparative Example 10 This comparative example provides an anti-fog high-barrier and matting film with a total thickness of 18 μm, comprising a 2.0-μm anti-fog barrier and matting layer, a 14.2-μm core layer, and a 1.8-μm bottom coating layer.

[0109] The anti-fog barrier and matting layer comprises 43 wt% of high-density polyethylene, 7 wt% of N-n-docosyldiethanolamine acrylate graft-modified propylene-norbornene copolymer, 1.2 wt% of maleic anhydride grafted isotactic polypropylene, and 48.8 wt% of random copolymerized polypropylene. Among them, the grafting rate of N-n-docosyldiethanolamine acrylate in the N-n-docosyldiethanolamine acrylate graft-modified propylene-norbornene copolymer is 1.5 wt%.

[0110] The core layer comprises 99 wt% of isotactic polypropylene with an isotacticity of 95% and a melt index of 3.6 g / 10 min, and 1 wt% of an antistatic agent.

[0111] The bottom coating layer comprises 12 wt% of propylene-butene copolymer, 3.5 wt% of alkyl maleate graft-modified ethylene-vinyl acetate copolymer, 0.5 wt% of polyorganosiloxane elastomer, 0.1 wt% of antioxidant, and 83.9 wt% of ethylene-octene copolymer. Among them, the grafting rate of alkyl maleate in the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 20 wt%.

[0112] The preparation method of the anti-fog high-barrier and matting film of this comparative example is the same as that of Example 1.

[0113] Performance test The anti-fog high-barrier matte films prepared in Examples 1 to 3 and Comparative Examples 1 to 10 were used to laminate printed materials, and the performance of the anti-fog high-barrier matte films and the laminated printed materials was tested. The test results are shown in Table 2.

[0114] Among them, the specific physical property indexes and their test methods are as follows: Evaluation of anti-fog performance: The anti-fog performance of the film was tested according to GB / T31726-2015, specifically the cold fog method and the water bath hot fog method; among them, grade 1 represents completely transparent without water droplets, grade 2 represents better transparency with a small amount of uneven large water droplets, grade 3 represents basically transparent with more water droplets, grade 4 represents semi-transparent with many small water beads, and grade 5 represents completely opaque.

[0115] The glossiness test was carried out according to the standard of GB / T8807-1988, and the haze test was carried out according to GB / T2410-2008.

[0116] Evaluation of the bonding strength between the bottom coating and the hot melt adhesive layer: EVA hot melt adhesive (VA content is 18wt%, melt index is 15g / 10min) was coated on the surface of the bottom coating, the coating thickness was 5μm, and after coating, a 3M adhesive tape was used for interlayer peeling test to observe whether the EVA hot melt adhesive layer peeled off.

[0117] Evaluation of the peeling strength (N / 15mm) between the film coated with the hot melt adhesive layer and the printed material: It was measured with reference to GB / T8808 (Method A), and the unit was N / 15mm; the digital printed material for lamination used in the present invention was a 250g white card black spot color printed material (the ink contained 0.5wt% silicone oil), and the laminated printed material was obtained by laminating under the conditions of 100°C, 10MPa, and 20m / min, and then the laminated printed material was cured at 45°C and a humidity of 80% for 5h, and the peeling strength was measured under the constant temperature and humidity conditions of 25°C and 80% humidity. It should be noted that usually the peeling strength test is carried out under the condition of a humidity of 45-55%, and the present invention considers the humid application environment, and the environmental humidity is controlled at 80% to evaluate the peeling effect of the film of the present invention in a high-humidity environment.

[0118] Table 2 - Test results of anti-fog high-barrier matte films and laminated printed materials

[0119] As can be seen from Table 2, the films prepared in Examples 1-3 have excellent anti-fogging properties, with both cold anti-fogging and hot anti-fogging properties reaching Grade 1; the bonding strength between the bottom coating and the hot melt adhesive layer is strong, and no peeling occurs between the bottom coating and the hot melt adhesive layer under the test conditions. Even under humid conditions, it has a high peeling strength and is suitable for use under humid conditions; in addition, when preparing the films in Examples 1-3, the production process is smooth and there is no delamination.

[0120] Compared with Example 2, in Comparative Example 1, both the cold anti-fogging and hot anti-fogging properties are reduced to Grade 4, the bonding strength between the bottom coating and the hot melt adhesive layer is reduced, and block tearing occurs during peeling. The peeling strength between the film coated with hot melt adhesive and the printed matter is low under humid conditions. This is because the content of N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer is too low to effectively improve the anti-fogging performance of the film and cannot enhance the barrier performance, thus unable to jointly improve and ensure the bonding strength between the bottom coating and the hot melt adhesive layer in cooperation with the bottom coating.

[0121] Compared with Example 2, in Comparative Example 2, both the cold anti-fogging and hot anti-fogging properties are reduced to Grade 2, and the production smoothness is poor, with delamination occurring during production. This is because the content of N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer is too high. Although the anti-fogging performance is improved to some extent, due to its poor dispersibility in the anti-fogging barrier and matting layer, the anti-fogging uniformity is poor, which is not conducive to the overall anti-fogging performance; in addition, when the addition amount of N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer is too high, the viscosity difference between the matting layer and the core layer will be too large, resulting in delamination during the production process.

[0122] Compared with Example 2, in Comparative Example 3, both the cold anti-fogging and hot anti-fogging properties are reduced to Grade 4, the bonding strength between the bottom coating and the hot melt adhesive layer is reduced, and block tearing occurs during peeling. The peeling strength between the film coated with hot melt adhesive and the printed matter is low under humid conditions. This is because the grafting rate of N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer is too low, resulting in too few hydrophilic groups and unable to play an effective anti-fogging role; in addition, too low grafting rate will also be unable to cooperate with the propylene-norbornene copolymer to play a barrier role, and thus unable to jointly improve and ensure the bonding strength between the bottom coating and the hot melt adhesive layer in cooperation with the bottom coating.

[0123] Compared with Example 2, in Comparative Example 4, both the cold anti-fogging and hot anti-fogging properties are reduced to Grade 2. This is because the grafting rate of N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer is too high, resulting in too strong intermolecular forces such as hydrogen bonds between the molecules of N-hexadecyl diethanolamine acrylate graft-modified propylene-norbornene copolymer itself, forming a physical crosslinked structure and unable to be evenly dispersed in the matting layer, thus unable to effectively improve the anti-fogging performance of the film.

[0124] Compared with Example 2, in Comparative Example 5, the bonding strength between the primer coat and the hot melt adhesive layer decreased, and block tearing occurred during peeling. The peeling strength between the film coated with hot melt adhesive and the printed matter was relatively low under humid conditions. This was because alkyl maleate graft-modified ethylene-vinyl acetate copolymer was not added to the primer coat, resulting in insufficient bonding strength between the primer coat and the hot melt adhesive layer.

[0125] Compared with Example 2, in Comparative Example 6, the production smoothness was poor, and the phenomenon of sticking to the roller occurred during production. This was because the content of alkyl maleate graft-modified ethylene-vinyl acetate copolymer was too high, increasing the viscosity of the primer coat, and thus causing the phenomenon of sticking to the roller during production.

[0126] Compared with Example 2, in Comparative Example 7, the bonding strength between the primer coat and the hot melt adhesive layer decreased, and block tearing occurred during peeling. The peeling strength between the film coated with hot melt adhesive and the printed matter was relatively low under humid conditions. This was because the grafting rate of alkyl maleate graft-modified ethylene-vinyl acetate copolymer was too low, resulting in a low content of polar ester groups, and unable to cooperate with the matting layer to ensure the bonding strength between the primer coat and the hot melt adhesive layer, especially in a humid environment.

[0127] Compared with Example 2, in Comparative Example 8, the production smoothness was poor, and the phenomenon of sticking to the roller occurred during production. This was because the grafting rate of alkyl maleate graft-modified ethylene-vinyl acetate copolymer was too high, resulting in a decrease in the thermal stability of alkyl maleate graft-modified ethylene-vinyl acetate copolymer itself, thermal decomposition occurred at the production process temperature, and thus the primer coat was too sticky, causing sticking to the roller.

[0128] Compared with Example 2, in Comparative Example 9, both the cold anti-fogging property and the hot anti-fogging property decreased to Grade 4. This was because the alkyl chain of N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer was too short, and its hydrophilic segment was difficult to move away from the low-polar resin matrix and face the outside of the film, and thus could not effectively improve the anti-fogging performance of the film.

[0129] Compared with Example 2, in Comparative Example 10, both the cold anti-fogging property and the hot anti-fogging property decreased to Grade 3. This was because the alkyl chain of N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer was too long, resulting in too large steric hindrance, and its hydrophilic segment could not be effectively unfolded on the film surface, and thus could not effectively improve the anti-fogging performance of the film.

[0130] In summary, in the present invention, N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer is added to the anti-fog barrier and matting layer, and by controlling the appropriate grafting rate and the length of the alkyl chain, the film has good anti-fog performance and certain barrier properties; maleic anhydride grafted homopolypropylene is also added to make the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer disperse uniformly in the anti-fog barrier and matting layer, and at the same time enhance the bonding force between the anti-fog barrier and matting layer with a relatively large polarity and the core layer, avoiding delamination during production and use; by adding alkyl maleate graft-modified ethylene-vinyl acetate copolymer to the primer layer and controlling the appropriate grafting rate, the bonding force between the primer layer of the film and the hot melt adhesive layer is improved; by adding propylene-butene copolymer to the primer layer, the interfacial compatibility between the primer layer and the core layer is improved. Under the synergistic effect of the differential functions of the anti-fog barrier and matting layer and the primer layer, the bonding force between the primer layer of the film and the hot melt adhesive in a humid environment is enhanced.

[0131] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation to the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. An anti-fog high-barrier matte film, characterized in that, It includes an anti-fog barrier and matting layer, a core layer, and a bottom coating layer that are sequentially arranged; The anti-fog barrier and matting layer includes random copolymerized polypropylene, 40-46 wt% high-density polyethylene, 4-10 wt% N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer, and 1-2 wt% maleic anhydride grafted homopolypropylene; wherein, the grafting rate of N-(n-alkyl) diethanolamine acrylate in the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer is 1-2.5%, and n is any integer from 14 to 18; The core layer includes homopolypropylene; The bottom coating layer includes ethylene-octene copolymer, 10-15 wt% propylene-butene copolymer, and 2-5 wt% alkyl maleate graft-modified ethylene-vinyl acetate copolymer; wherein, the grafting rate of alkyl maleate in the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 12-30%.

2. The anti-fog high-barrier matte film according to claim 1, wherein At 230 °C under a load of 2.16 kg, the melt index of the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer is 5-10 g / 10 min; the N-(n-alkyl) diethanolamine acrylate graft-modified propylene-norbornene copolymer is obtained by grafting N-(n-alkyl) diethanolamine acrylate onto a propylene-norbornene copolymer, and the molar content of norbornene in the propylene-norbornene copolymer is 25-28%.

3. The anti-fog high-barrier matte film according to claim 2, wherein At 230 °C under a load of 2.16 kg, the melt index of the random copolymerized polypropylene is 6-10 g / 10 min; at 190 °C under a load of 2.16 kg, the melt index of the high-density polyethylene is 9-20 g / 10 min; the random copolymerized polypropylene is selected from one or two of ethylene-propylene copolymerized polypropylene or ethylene-propylene-butene copolymerized polypropylene.

4. The anti-fog high-barrier matte film according to claim 1, wherein The isotacticity of the homopolypropylene is 90-99%, and at 230 °C under a load of 2.16 kg, the melt index is 3.5-3.8 g / 10 min.

5. The anti-fog high-barrier matte film according to claim 1, wherein At 190 °C under a load of 2.16 kg, the melt index of the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 26-28 g / 10 min; the melting point of the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is 80-90 °C; the alkyl maleate graft-modified ethylene-vinyl acetate copolymer is obtained by grafting an alkyl maleate onto an ethylene-vinyl acetate copolymer, and the melt index of the ethylene-vinyl acetate copolymer is 20-25 g / 10 min.

6. The anti-fog high-barrier matte film according to claim 5, wherein The alkyl maleate in the alkyl maleate graft-modified ethylene-vinyl acetate copolymer has a double ester group structure, and the alkyl maleate is any one of di-n-octyl maleate or di-n-butyl maleate.

7. The anti-fog high-barrier matte film according to claim 1, wherein The melting point of the ethylene-octene copolymer is 75-95 °C, and the melting point of the propylene-butene copolymer is 80-95 °C.

8. The anti-fog high-barrier matte film according to claim 1, wherein The bottom coating further comprises 0.5-1 wt% of a polyorganosiloxane elastomer, and the particle size D90 of the polyorganosiloxane elastomer is 3-5 μm.

9. A method for preparing an anti-fog high-barrier matte film according to any one of claims 1 to 8, characterized in that, The method comprises the following steps: Respectively input the component raw materials of the anti-fog barrier and matting layer, the core layer, and the bottom coating into a batching unit. After metering, they are co-extruded through an extruder, converge in a three-layer die head via a runner distributor, and then form a thick sheet after cooling by a chill roll. The thick sheet is biaxially stretched by a stretching roll to form a film. The film is cooled, and at the same time, thickness control is carried out by a trimming machine, and then corona and / or flame treatment is carried out to obtain the anti-fog high-barrier and matting film.

10. The preparation method of an anti-fog high-barrier matte film according to claim 9, characterized in that, The surface of the bottom coating feeding tank of the extruder and the surface of the stretching roll used in biaxial stretching are provided with Teflon coatings.

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