Polyolefin functional adhesive film as well as preparation method and application thereof

Abstract

The invention relates to the technical field of functional adhesive films, in particular to a polyolefin functional adhesive film as well as a preparation method and application thereof. The polyolefin functional adhesive film comprises a surface layer, a middle layer and an inner layer which are sequentially stacked in the thickness direction of the polyolefin functional adhesive film. The surface layer comprises an olefin copolymer, a polyethylene-ester copolymer, a cross-linking sensitizer, an assistant cross-linking agent, an antioxidant and a light stabilizer; the middle layer comprises an olefin copolymer, a polyethylene-ester copolymer, titanium dioxide, an antioxidant and a light stabilizer; the inner layer comprises an olefin copolymer, a polyethylene-ester copolymer and a maleic anhydride modified polyethylene-ester copolymer. Through the multi-layer structural design, the polyolefin functional adhesive film has excellent adhesive performance and weather resistance, and can be used for corrosion prevention of outdoor metal materials.

Description

Technical Field

[0001] The present invention relates to the technical field of functional adhesive films, in particular to a polyolefin functional adhesive film and a preparation method and application thereof. Background Art

[0002] In the field of modern building materials, metal materials are widely used in various outdoor engineering structures due to their excellent mechanical strength, processing characteristics and durability. However, metal materials are prone to corrosion in outdoor environments, which in turn affects their service life and service safety. Currently, three protective technologies are mainly used for outdoor metal corrosion protection: paint, powder coating and polymer film. Among them, traditional paint has problems such as environmental pollution and harm to the health of construction workers during the coating process; powder coating is relatively environmentally friendly, but the coating quality is limited by its own thickness. If it is too thin, it is easy to leak the coating, affecting the anti-corrosion effect. In contrast, polymer film coating has won a larger market share with its excellent environmental protection and uniform coating thickness. It has begun to be widely used in communication base stations, building curtain walls, roof corrosion protection and engineering waterproofing.

[0003] Among them, polyolefin film coating has developed into the leading product in the current metal anti-corrosion market with its advantages of good environmental protection, corrosion resistance, and cost-effectiveness, occupying the largest market share in the field of polymer film coating.

[0004] Polyolefin films inherently offer excellent weather resistance and low water vapor permeability, effectively preventing direct contact between corrosive substances and metal substrates. However, achieving this protective function requires ensuring a strong and reliable bonding interface between the film and the metal. Because polyolefins typically have low surface polarity and surface energy, the significant difference in surface energy between them and the metal substrate makes it difficult to directly form a stable bond. Therefore, in practical applications, the molecular structure of the polyolefin is often modified and optimized to enhance its interfacial bonding properties with the metal.

[0005] At the same time, polyolefin films face challenges in outdoor engineering applications, including low surface hardness, poor scratch resistance, and insufficient heat resistance. These issues lead to localized damage during transportation, construction, and service, ultimately impacting their overall weather resistance and corrosion resistance. To address these issues, Chinese patent application publication number CN108485159A proposes the introduction of cyclic olefin copolymer (COC) into polyolefins to improve the heat resistance of polyolefin films. However, COC's high cost makes it difficult to achieve the economic viability required for large-scale industrial production.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] The purpose of the present invention is to provide a polyolefin functional adhesive film, a preparation method and an application thereof. The polyolefin functional adhesive film of the present invention has excellent bonding performance, weather resistance and low cost through a multi-layer structure, thereby solving the performance challenges faced by existing polyolefin films in outdoor applications.

[0008] In order to achieve the above-mentioned object of the present invention, the first aspect of the present invention provides a polyolefin functional adhesive film, wherein the polyolefin functional adhesive film comprises a surface layer, an intermediate layer and an inner layer sequentially stacked along the thickness direction thereof; The surface layer comprises the following components in parts by weight: 70-80 parts of olefin copolymer, 15-30 parts of polyethylene-ester copolymer, 0.5-2 parts of crosslinking sensitizer, 0.1-0.3 parts of auxiliary crosslinking agent, 0.1-1 parts of antioxidant and 0.1-0.2 parts of light stabilizer; The intermediate layer comprises the following components in parts by weight: 40 to 50 parts of olefin copolymer, 35 to 55 parts of polyethylene-ester copolymer, 10 to 15 parts of titanium dioxide, 0.1 to 1 part of antioxidant and 0.1 to 0.2 part of light stabilizer; The inner layer comprises the following components in parts by weight: 10 to 30 parts of olefin copolymer, 40 to 70 parts of polyethylene-ester copolymer and 20 to 40 parts of maleic anhydride modified polyethylene-ester copolymer.

[0009] In a specific embodiment of the present invention, the olefin copolymer in the surface layer, the olefin copolymer in the middle layer, and the olefin copolymer in the inner layer are each independently selected from at least one of polyethylene-propylene copolymer, polyethylene-butene copolymer, polyethylene-octene copolymer and amorphous α-olefin copolymer.

[0010] In a specific embodiment of the present invention, the polyethylene-ester copolymer in the surface layer, the polyethylene-ester copolymer in the middle layer, and the polyethylene-ester copolymer in the inner layer are each independently selected from at least one of polyethylene-vinyl acetate copolymer, polyethylene-methyl acrylate copolymer, polyethylene-ethyl acrylate copolymer and polyethylene-butyl acrylate copolymer.

[0011] In a specific embodiment of the present invention, the olefin copolymer in the surface layer, the olefin copolymer in the middle layer, and the olefin copolymer in the inner layer are of the same type; the polyethylene-ester copolymer in the surface layer, the polyethylene-ester copolymer in the middle layer, and the polyethylene-ester copolymer in the inner layer are of the same type.

[0012] In a specific embodiment of the present invention, in the surface layer, the amount of the olefin copolymer is 72% to 80% of the total mass of the olefin copolymer and the polyethylene-ester copolymer.

[0013] In a specific embodiment of the present invention, in the intermediate layer, the amount of the olefin copolymer is 45% to 55% of the total mass of the olefin copolymer and the polyethylene-ester copolymer.

[0014] In a specific embodiment of the present invention, in the inner layer, the amount of the olefin copolymer is 30% to 40% of the total mass of the olefin copolymer and the polyethylene-ester copolymer.

[0015] In a specific embodiment of the present invention, the crosslinking sensitizer includes at least one of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butylperoxy-3,5,5-trimethylhexanoate, triallyl isocyanate, 4,4-di(tert-amylperoxy)valerate, tert-butyl peroxy-2-ethylhexyl carbonate and ethyl 3,3-di(tert-butylperoxy)butyrate.

[0016] In a specific embodiment of the present invention, the auxiliary cross-linking agent includes at least one of tris(2-hydroxyethyl)isocyanurate triacrylate, trimethylolpropane triacrylate, triallyl cyanurate, triallyl isocyanurate, pentaerythritol triacrylate and ethoxylated trimethylolpropane triacrylate.

[0017] In a specific embodiment of the present invention, the maleic anhydride-modified polyethylene-ester copolymer includes at least one of a maleic anhydride-modified polyethylene-vinyl acetate copolymer, a maleic anhydride-modified polyethylene-methyl acrylate copolymer, a maleic anhydride-modified polyethylene-ethyl acrylate copolymer, and a maleic anhydride-modified polyethylene-butyl acrylate copolymer. Furthermore, the maleic anhydride-modified polyethylene-ester copolymer has a grafting rate of maleic anhydride of 0.5 wt% to 2 wt%.

[0018] In a specific embodiment of the present invention, the total thickness of the polyolefin functional adhesive film is 0.15 to 0.4 mm. Furthermore, in the polyolefin functional adhesive film, the thickness of the surface layer accounts for 25% to 50% of the total thickness of the polyolefin functional adhesive film; the thickness of the middle layer accounts for 40% to 70% of the total thickness of the polyolefin functional adhesive film; and the thickness of the inner layer accounts for 5% to 10% of the total thickness of the polyolefin functional adhesive film.

[0019] The second aspect of the present invention provides a method for preparing the polyolefin functional adhesive film of the first aspect of the present invention, comprising the following steps: co-extruding the raw materials of the surface layer, the raw materials of the middle layer and the raw materials of the inner layer in multiple layers, and then subjecting the surface side of the film obtained by the multi-layer co-extrusion to electron beam irradiation treatment to obtain the polyolefin functional adhesive film.

[0020] In a specific embodiment of the present invention, during the electron beam irradiation treatment, the surface layer is crosslinked, while the intermediate layer and the inner layer are not crosslinked; the pre-crosslinking degree of the surface layer is greater than 5%. Furthermore, during the electron beam irradiation treatment, the irradiation dose is 100 to 180 kGy.

[0021] The third aspect of the present invention provides the use of the polyolefin functional adhesive film of the first aspect of the present invention in the corrosion protection of outdoor metal materials.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention adopts a multi-layer structural design to make the polyolefin functional adhesive film have both excellent bonding performance and weather resistance; specifically, the inner layer gives the film an adhesive function, which can ensure long-term bonding with the metal; the surface layer has heat resistance and hardness, giving the film excellent weather resistance; the middle layer can not only achieve a reliable connection between the surface layer and the inner layer, but also protect the inner layer and the metal material from ultraviolet corrosion and aging; the polyolefin functional adhesive film thus obtained solves the key performance problems faced by existing polyolefin films in outdoor metal anti-corrosion applications.

[0023] (2) In the preparation of the polyolefin functional adhesive film of the present invention, a combination of multi-layer co-extrusion and radiation cross-linking is adopted. The cross-linking structure and cross-linking degree of the polyolefin are controlled by radiation treatment and the ratio of raw materials. The surface layer of the irradiated polyolefin functional adhesive film is cross-linked, while the middle layer and the inner layer are not cross-linked. The middle layer can play a stable self-supporting role. The film has no obvious wrinkling and shrinkage before and after the radiation treatment, thereby ensuring the smoothness and aesthetics of the surface of the film product. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 This is a schematic structural diagram of a polyolefin functional adhesive film provided by an embodiment of the present invention.

[0026] Reference numerals: 1-surface layer; 2-middle layer; 3-inner layer. DETAILED DESCRIPTION

[0027] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. Those who do not specify specific conditions in the embodiments are carried out according to normal conditions or the conditions recommended by the manufacturer. Those whose reagents or instruments are not specified by the manufacturer are conventional products that can be purchased commercially.

[0028] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0029] The first aspect of the present invention provides a polyolefin functional adhesive film, Figure 1 Schematic diagram of the structure of the polyolefin functional adhesive film provided by the embodiment of the present invention; Figure 1 As shown, the polyolefin functional adhesive film provided by the present invention includes a surface layer 1, an intermediate layer 2 and an inner layer 3 which are sequentially stacked along the thickness direction thereof.

[0030] The surface layer 1 comprises the following components in parts by weight: 70-80 parts of olefin copolymer, 15-30 parts of polyethylene-ester copolymer, 0.5-2 parts of crosslinking sensitizer, 0.1-0.3 parts of auxiliary crosslinking agent, 0.1-1 parts of antioxidant and 0.1-0.2 parts of light stabilizer; The intermediate layer 2 comprises the following components in parts by weight: 40 to 50 parts of olefin copolymer, 35 to 55 parts of polyethylene-ester copolymer, 10 to 15 parts of titanium dioxide, 0.1 to 1 part of antioxidant and 0.1 to 0.2 part of light stabilizer; The inner layer 3 comprises the following components in parts by weight: 10 to 30 parts of olefin copolymer, 40 to 70 parts of polyethylene-ester copolymer and 20 to 40 parts of maleic anhydride-modified polyethylene-ester copolymer.

[0031] The present invention uses a multi-layer structural design to enable the polyolefin functional adhesive film to have both excellent bonding performance and weather resistance; specifically, by regulating the components of each layer, the inner layer imparts the film with bonding function, which can ensure long-lasting bonding with the metal; the surface layer has heat resistance and hardness, giving the film excellent weather resistance; the middle layer can not only achieve reliable connection between the surface layer and the inner layer, but also protect the inner layer and the metal material from ultraviolet corrosion and aging; the polyolefin functional adhesive film thus obtained solves the key performance problems faced by existing polyolefin films in outdoor applications.

[0032] For example, in different embodiments, in the surface layer 1, the amounts of each component can be as follows, by weight: the amount of the olefin copolymer can be 70 parts, 72 parts, 75 parts, 78 parts, 80 parts or a range consisting of any two thereof; the amount of the polyethylene-ester copolymer can be 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, 28 parts, 30 parts or a range consisting of any two thereof; the amount of the cross-linking sensitizer can be 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 2.5 parts, 3.0 parts, 4.5 parts, 5.0 parts, 6.0 parts, 7.5 parts, 8.0 parts, 9.0 parts, 10.0 parts, 11.0 parts, 12.0 parts, 13.0 parts, 14.0 parts, 15.0 parts, 16.0 parts, 17.0 parts, 18.0 parts, 19.0 parts, 20.0 parts, 21.0 parts, 22.0 parts, 25.0 parts, 28.0 parts, 30.0 parts, The amount of the surface layer components can be adjusted within the above ranges, and the irradiation treatment during the preparation process can be combined to ensure that the surface layer is coordinated with the remaining layers, thereby improving the adhesive properties, mechanical properties, and weather resistance of the polyolefin functional adhesive film.

[0033] For example, in different embodiments, in the intermediate layer 2, the amounts of each component can be as follows, calculated in parts by weight: the amount of olefin copolymer can be 40 parts, 42 parts, 45 parts, 48 ​​parts, 50 parts or a range consisting of any two thereof; the amount of polyethylene-ester copolymer can be 35 parts, 38 parts, 40 parts, 42 parts, 45 parts, 48 ​​parts, 50 parts, 52 parts, 55 parts or a range consisting of any two thereof; the amount of titanium dioxide can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts or a range consisting of any two thereof; the amount of antioxidant can be 0.1 part, 0.3 part, 0.5 part, 0.8 part, 1 part or a range consisting of any two thereof; the amount of light stabilizer can be 0.1 part, 0.12 part, 0.15 part, 0.18 part, 0.2 part or a range consisting of any two thereof. By regulating the amount of each component in the middle layer within the above range, the surface layer and the inner layer can be matched to improve the connection reliability between the surface layer and the inner layer, and play its supporting role, so that the film will not show obvious wrinkling and shrinkage after radiation cross-linking.

[0034] For example, in different embodiments, in the inner layer 3, the amount of each component can be as follows in parts by weight: the amount of olefin copolymer can be 10 parts, 15 parts, 20 parts, 25 parts, 30 parts or a range consisting of any two thereof; the amount of polyethylene-ester copolymer can be 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts or a range consisting of any two thereof; the amount of maleic anhydride-modified polyethylene-ester copolymer can be 20 parts, 25 parts, 30 parts, 35 parts, 40 parts or a range consisting of any two thereof. The inner layer of the present invention can form a reliable and long-lasting bond with the metal material under hot pressing and laminating conditions. By regulating the amount of each component in the inner layer within the above range, it can maintain long-lasting bonding performance with the metal material, and can cooperate with the remaining layers to improve the mechanical properties, weather resistance, etc. of the polyolefin functional adhesive film.

[0035] In a specific embodiment of the present invention, the olefin copolymer in the surface layer, the olefin copolymer in the middle layer, and the olefin copolymer in the inner layer are each independently selected from at least one of polyethylene-propylene copolymer, polyethylene-butene copolymer, polyethylene-octene copolymer and amorphous α-olefin copolymer.

[0036] In a specific embodiment of the present invention, the polyethylene-ester copolymer in the surface layer, the polyethylene-ester copolymer in the middle layer, and the polyethylene-ester copolymer in the inner layer are each independently selected from at least one of polyethylene-vinyl acetate copolymer, polyethylene-methyl acrylate copolymer, polyethylene-ethyl acrylate copolymer and polyethylene-butyl acrylate copolymer.

[0037] In a specific embodiment of the present invention, the olefin copolymer in the surface layer, the olefin copolymer in the middle layer, and the olefin copolymer in the inner layer are of the same type; and the polyethylene-ester copolymer in the surface layer, the polyethylene-ester copolymer in the middle layer, and the polyethylene-ester copolymer in the inner layer are of the same type. If the matrix resins in the layers are different, the cooling and crystallization rates of the matrix resins in the different layers may differ significantly during the coextrusion process, resulting in significant internal stress within the film after cooling and forming, causing the film to appear curled macroscopically, affecting normal use.

[0038] In a specific embodiment of the present invention, the amount of olefin copolymer in the surface layer is 72% to 80%, such as 72% to 75%, of the combined mass of the olefin copolymer and the polyethylene-ester copolymer; the amount of olefin copolymer in the middle layer is 45% to 55%, such as 48% to 52%, of the combined mass of the olefin copolymer and the polyethylene-ester copolymer; and the amount of olefin copolymer in the inner layer is 30% to 40%, such as 32% to 36%. In the polyolefin functional adhesive film of the present invention, the amount of olefin copolymer in the surface layer, middle layer, and inner layer respectively meets a certain range, which is more conducive to coordinating and controlling the cooling crystallization rate of each layer during the coextrusion film forming process, ensuring the matching of each layer, and more conducive to achieving a good balance between the mechanical properties, adhesive properties, and flatness of the adhesive film.

[0039] In a specific embodiment of the present invention, the crosslinking sensitizer includes at least one of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butylperoxy-3,5,5-trimethylhexanoate, triallyl isocyanate, n-butyl 4,4-di(tert-amylperoxy)valerate, tert-butyl peroxy-2-ethylhexyl carbonate, and ethyl 3,3-di(tert-butylperoxy)butyrate.

[0040] In a specific embodiment of the present invention, the auxiliary cross-linking agent includes at least one of tris(2-hydroxyethyl)isocyanurate triacrylate, trimethylolpropane triacrylate, triallyl cyanurate, triallyl isocyanurate, pentaerythritol triacrylate and ethoxylated trimethylolpropane triacrylate.

[0041] In a specific embodiment of the present invention, the maleic anhydride-modified polyethylene-ester copolymer includes at least one of a maleic anhydride-modified polyethylene-vinyl acetate copolymer, a maleic anhydride-modified polyethylene-methyl acrylate copolymer, a maleic anhydride-modified polyethylene-ethyl acrylate copolymer, and a maleic anhydride-modified polyethylene-butyl acrylate copolymer. Furthermore, the maleic anhydride-modified polyethylene-ester copolymer has a grafting rate of maleic anhydride of 0.5 wt % to 2 wt %.

[0042] In a specific embodiment of the present invention, the total thickness of the polyolefin functional adhesive film is 0.15-0.4 mm, such as 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, or any combination thereof. Furthermore, in the polyolefin functional adhesive film, the thickness of the surface layer accounts for 25%-50% of the total thickness of the polyolefin functional adhesive film, such as 25%, 30%, 35%, 40%, 45%, 50%, or any combination thereof; the thickness of the middle layer accounts for 40%-70% of the total thickness of the polyolefin functional adhesive film, such as 40%, 45%, 50%, 55%, 60%, 65%, 70%, or any combination thereof; and the thickness of the inner layer accounts for 5%-10% of the total thickness of the polyolefin functional adhesive film, such as 5%, 6%, 7%, 8%, 9%, 10%, or any combination thereof.

[0043] In a specific embodiment of the present invention, the light stabilizer in the surface layer and the light stabilizer in the middle layer are each independently selected from at least one of poly (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinylethanol) succinate, poly-{[6-[(1,1,3,3,-tetramethylbutyl)-imino]-1,3,5,-triazine-2,4-diyl][2-(2,2,6,6,-tetramethylpiperidinyl)-nitrilo-hexamethylene-[4-(2,2,6,6,-tetramethylpiperidinyl)-nitrilo]] and bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate.

[0044] In a specific embodiment of the present invention, the antioxidant in the surface layer and the antioxidant in the middle layer are each independently selected from at least one of antioxidant B215, antioxidant B245 and antioxidant 1010.

[0045] The second aspect of the present invention provides a method for preparing the polyolefin functional adhesive film of the first aspect of the present invention, comprising the following steps: co-extruding the raw materials of the surface layer, the raw materials of the middle layer and the raw materials of the inner layer in multiple layers, and then subjecting the surface side of the film obtained by the multi-layer co-extrusion to electron beam irradiation treatment to obtain the polyolefin functional adhesive film.

[0046] In the preparation of the polyolefin functional adhesive film of the present invention, electron beam irradiation is used to deionize and excite the polymer chains, causing them to undergo reorganization and crosslinking, forming an intertwined three-dimensional network structure. This gives the irradiated film enhanced mechanical properties and weather resistance. Furthermore, the preparation method of the present invention is simple to operate, environmentally friendly, and cost-effective, facilitating the industrial production of polyolefin functional adhesive films.

[0047] In a specific embodiment of the present invention, in multi-layer co-extrusion, the extrusion temperature is set to 160-210° C. The multi-layer co-extrusion can be carried out using conventional multi-layer co-extrusion equipment, and the extrusion temperature can be adjusted conventionally.

[0048] In a specific embodiment of the present invention, during the electron beam irradiation treatment, the surface layer is crosslinked, while the middle layer and the inner layer are not crosslinked; the pre-crosslinking degree of the surface layer is greater than 5%. Furthermore, the pre-crosslinking degree of the surface layer is 8% to 50%, preferably 10% to 30%, for example, 10%, 15%, 20%, 25%, 30%, or any combination thereof. Within this range, the surface layer of the film has a certain strength and heat resistance, while avoiding degradation of the polymer chains due to excessive irradiation.

[0049] In a specific embodiment of the present invention, in the electron beam irradiation treatment, the electron acceleration energy level is 0.15 to 2 MeV, the irradiation dose is 100 to 180 kGy, and the irradiation speed is 10 to 250 m / min.

[0050] The electron beam irradiation treatment of the present invention can be carried out in an air atmosphere at room temperature (e.g., 25°C).

[0051] In a specific embodiment of the present invention, the materials are separately prepared according to the components of the surface layer, the middle layer, and the inner layer, mixed, and then extruded and granulated to obtain the raw materials for the surface layer, the middle layer, and the inner layer, respectively. Furthermore, the extrusion granulation temperature is 180-210°C. The extrusion granulation can be carried out using a conventional twin-screw extruder, and the extrusion granulation temperature can be adjusted conventionally.

[0052] The third aspect of the present invention provides the use of the polyolefin functional adhesive film of the first aspect of the present invention in the corrosion protection of outdoor metal materials, wherein the metal materials include but are not limited to galvanized sheets.

[0053] Example 1 This embodiment provides a polyolefin functional adhesive film, comprising a surface layer, a middle layer, and an inner layer stacked in sequence along the thickness direction thereof.

[0054] The raw materials for the surface layer include the following components, by weight: 72 parts olefin copolymer, 26 parts polyethylene-ester copolymer, 1.5 parts crosslinking sensitizer, 0.1 parts co-crosslinking agent, 0.2 parts antioxidant, and 0.2 parts light stabilizer. The raw materials for the middle layer include the following components, by weight: 45 parts olefin copolymer, 44 parts polyethylene-ester copolymer, 10.7 parts titanium dioxide, 0.2 parts antioxidant, and 0.1 parts light stabilizer. The raw materials for the inner layer include the following components, by weight: 25 parts olefin copolymer, 48 parts polyethylene-ester copolymer, and 26.3 parts maleic anhydride-modified polyethylene-ester copolymer.

[0055] Among them, the olefin copolymers of the surface layer, middle layer and inner layer are all polyethylene-propylene copolymer (Sinopec PPB-M09), the polyethylene-ester copolymers of the surface layer, middle layer and inner layer are all polyethylene-vinyl acetate copolymer (Formosa EVA7320M), the cross-linking sensitizer of the surface layer is tert-butyl peroxy-3,5,5-trimethylhexanoate, the auxiliary cross-linking agent of the surface layer is trimethylolpropane triacrylate, the antioxidants of the surface layer and the middle layer are both B215, the light stabilizers of the surface layer and the middle layer are both bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, the titanium dioxide of the middle layer is masterbatch (Meili Lian RCL-69), and the maleic anhydride-modified polyethylene-ester copolymer of the inner layer is maleic anhydride-modified polyethylene-vinyl acetate copolymer (Guangzhou Lushan New Materials Co., Ltd., OV-1).

[0056] The preparation method of the polyolefin functional adhesive film of this embodiment includes the following steps: (1) According to the raw material composition of the surface layer, the middle layer and the inner layer, the ingredients are respectively prepared by extrusion granulation using a twin-screw extruder to obtain surface layer pellets, middle layer pellets and inner layer pellets respectively; wherein, the temperatures of the first to sixth zones of the surface layer pellet extruder are: 60-80℃, 80-100℃, 100-120℃, 120-160℃, 160-180℃, 180-210℃, and the die head temperature is set to 200℃; the temperature of the first zone of the middle layer pellet extruder is set to 200℃. The temperatures of zones 1 to 6 are: 60-80°C, 80-100°C, 100-120°C, 120-160°C, 160-180°C, 180-210°C, and the die head temperature is set to 200°C; the temperatures of zones 1 to 6 of the inner layer pellet extruder are: 60-80°C, 80-100°C, 100-120°C, 120-160°C, 160-180°C, 180-210°C, and the die head temperature is set to 200°C.

[0057] (2) The surface layer pellets, the middle layer pellets, and the inner layer pellets are co-extruded through multiple layers and cooled to form a film; then one side of the surface layer is subjected to single-sided electron beam irradiation treatment to obtain a polyolefin functional adhesive film.

[0058] In step (2), in the multi-layer co-extrusion, the extrusion temperature range of the surface layer, middle layer and inner layer pellets of the three-layer extruder is set to 180-210°C, and the co-extrusion die head temperature is 200°C; the total thickness of the polyolefin functional adhesive film is 300 μm, and the thicknesses of the surface layer, middle layer and inner layer are 90 μm, 180 μm and 30 μm respectively; in the electron beam single-sided irradiation treatment, the energy level of the electron accelerator is 0.16 MeV, the irradiation dose is 120 kGy, and the irradiation speed is 20 m / min; after the electron beam single-sided irradiation treatment, the surface layer crosslinking degree test is 10%, and the middle layer and the inner layer are not crosslinked.

[0059] Example 2 This embodiment refers to the polyolefin functional adhesive film and its preparation method of Example 1, with the only difference being the amounts of the raw materials for the surface layer, the middle layer, and the inner layer. The rest is the same as Example 1. The specific differences are as follows.

[0060] In this embodiment, the raw materials of the surface layer include the following components in parts by weight: 80 parts of olefin copolymer, 16.5 parts of polyethylene-ester copolymer, 2 parts of crosslinking sensitizer, 0.3 parts of co-crosslinking agent, 1 part of antioxidant and 0.2 parts of light stabilizer; The raw materials of the intermediate layer include the following components in parts by weight: 40 parts of olefin copolymer, 49 parts of polyethylene-ester copolymer, 10.7 parts of titanium dioxide, 0.2 parts of antioxidant and 0.1 parts of light stabilizer; The raw materials of the inner layer include the following components in parts by weight: 10 parts of olefin copolymer, 70 parts of polyethylene-ester copolymer and 20 parts of maleic anhydride-modified polyethylene-ester copolymer.

[0061] Example 3 This embodiment refers to the polyolefin functional adhesive film and its preparation method of Example 1, with the only difference being the amounts of the raw materials for the surface layer, the middle layer, and the inner layer. The rest is the same as Example 1. The specific differences are as follows.

[0062] In this embodiment, the raw materials of the surface layer include the following components in parts by weight: 70 parts of olefin copolymer, 29.2 parts of polyethylene-ester copolymer, 0.5 parts of crosslinking sensitizer, 0.1 parts of auxiliary crosslinking agent, 0.1 parts of antioxidant and 0.1 parts of light stabilizer.

[0063] The raw materials of the middle layer include the following components in parts by weight: 50 parts of olefin copolymer, 35 parts of polyethylene-ester copolymer, 14.7 parts of titanium dioxide, 0.2 parts of antioxidant and 0.1 parts of light stabilizer.

[0064] The raw materials of the inner layer include the following components in parts by weight: 30 parts of olefin copolymer, 40 parts of polyethylene-ester copolymer and 30 parts of maleic anhydride-modified polyethylene-ester copolymer.

[0065] Example 4 This embodiment refers to the polyolefin functional adhesive film and its preparation method of Example 1, with the only difference being that some parameters of the electron beam single-sided irradiation treatment in the preparation of the polyolefin functional adhesive film are different, and the rest are the same as Example 1. The specific differences are as follows.

[0066] In this embodiment, the electron beam single-sided irradiation treatment has an electron irradiation dose of 160 kGy. After the electron beam single-sided irradiation treatment, the surface layer crosslinking degree test is 50%, and the middle layer and the inner layer are not crosslinked.

[0067] Example 5 This embodiment refers to the polyolefin functional adhesive film and its preparation method of Example 1, with the only difference being that some parameters of the electron beam single-sided irradiation treatment in the preparation of the polyolefin functional adhesive film are different, and the rest are the same as Example 1. The specific differences are as follows.

[0068] In this embodiment, the electron beam single-sided irradiation treatment has an electron irradiation dose of 140 kGy. After the electron beam single-sided irradiation treatment, the surface layer crosslinking degree test is 30%, and the middle layer and the inner layer are not crosslinked.

[0069] Example 6 This embodiment group refers to the polyolefin functional adhesive film and its preparation method of Example 1, with the only difference being that the amount of raw materials used in the surface layer is different, and the rest is the same as Example 1. The specific differences are as follows.

[0070] Example 6a: The raw materials of the surface layer include the following components in parts by weight: 80 parts of olefin copolymer, 18 parts of polyethylene-ester copolymer, 1.5 parts of crosslinking sensitizer, 0.1 parts of co-crosslinking agent, 0.2 parts of antioxidant and 0.2 parts of light stabilizer; Example 6b: The raw materials of the surface layer include the following components in parts by weight: 70 parts of olefin copolymer, 28 parts of polyethylene-ester copolymer, 1.5 parts of crosslinking sensitizer, 0.1 parts of co-crosslinking agent, 0.2 parts of antioxidant and 0.2 parts of light stabilizer.

[0071] Example 7 Group This embodiment group refers to the polyolefin functional adhesive film and its preparation method of Example 1, with the only difference being that the amount of raw materials used in the intermediate layer is different, and the rest is the same as Example 1. The specific differences are as follows.

[0072] Example 7a: The raw materials of the intermediate layer include the following components in parts by weight: 50 parts of olefin copolymer, 39 parts of polyethylene-ester copolymer, 10.7 parts of titanium dioxide, 0.2 parts of antioxidant and 0.1 parts of light stabilizer; Example 7b: The raw materials of the intermediate layer include the following components in parts by weight: 40 parts of olefin copolymer, 49 parts of polyethylene-ester copolymer, 10.7 parts of titanium dioxide, 0.2 parts of antioxidant and 0.1 parts of light stabilizer.

[0073] Example 8 Group This embodiment group refers to the polyolefin functional adhesive film and its preparation method of Example 1, with the only difference being that the amount of raw materials used in the inner layer is different, and the rest is the same as Example 1. The specific differences are as follows.

[0074] Example 8a: The raw materials of the inner layer include the following components in parts by weight: 30 parts of olefin copolymer, 43 parts of polyethylene-ester copolymer and 26.3 parts of maleic anhydride-modified polyethylene-ester copolymer; Example 8b: The raw materials of the inner layer include the following components in parts by weight: 21 parts of olefin copolymer, 52 parts of polyethylene-ester copolymer and 26.3 parts of maleic anhydride-modified polyethylene-ester copolymer.

[0075] Example 9 This embodiment group refers to the polyolefin functional adhesive film and its preparation method of Example 1, with the only difference being the type of olefin copolymer in the middle layer. The rest is the same as Example 1. The specific differences are as follows.

[0076] The olefin copolymer used in the middle layer of this embodiment is an amorphous α-olefin copolymer (Huntsman APAORT52627).

[0077] Comparative Example 1 Comparative Example 1 The polyolefin functional adhesive film and preparation method thereof are referred to in Example 1, except that: the surface layer structure is not included; after cooling to form the film, one side of the intermediate layer is subjected to single-sided electron beam irradiation treatment; and the thickness of the polyolefin functional adhesive film is 210 μm.

[0078] Comparative Example 2 Comparative Example 2 refers to the polyolefin functional adhesive film and its preparation method of Example 1, except that the amount of the raw material used in the surface layer is different, the electron irradiation dose is different, and the rest is the same as Example 1. The specific differences are as follows.

[0079] In Comparative Example 2, the surface layer materials included the following components, by weight: 72 parts of an olefin copolymer, 26 parts of a polyethylene-ester copolymer, 0.2 parts of an antioxidant, and 0.2 parts of a light stabilizer. The surface layer materials in Comparative Example 2 did not include a crosslinking sensitizer or a co-crosslinking agent. The electron irradiation dose was 160 kGy.

[0080] Comparative Example 3 Comparative Example 3 refers to the polyolefin functional adhesive film and its preparation method of Example 1, except that: in step (2) of preparing the film, after cooling to form the film, no single-sided electron beam irradiation treatment is performed.

[0081] Comparative Example 4 Comparative Example 4 refers to the polyolefin functional adhesive film and its preparation method of Comparative Example 1, with the difference that: in step (2) of preparing the film, after cooling to form the film, no single-sided electron beam irradiation treatment is performed.

[0082] Comparative Example 5 Comparative Example 5 refers to the polyolefin functional adhesive film and its preparation method of Comparative Example 2, except that: in step (2) of preparing the film, after cooling to form the film, no single-sided electron beam irradiation treatment is performed.

[0083] Comparative Example 6 Comparative Example 6 refers to the polyolefin functional adhesive film and its preparation method of Example 1, except that the amount of raw materials used in the surface layer and the middle layer is different, and the rest is the same as Example 1. The specific differences are as follows.

[0084] In Comparative Example 6, the raw materials for the surface layer included the following components, by weight: 98 parts polyethylene-ester copolymer (Formosa EVA 7320M), 1.5 parts crosslinking sensitizer, 0.1 parts co-crosslinking agent, 0.2 parts antioxidant, and 0.2 parts light stabilizer. The raw materials for the middle layer included the following components, by weight: 89 parts polyethylene-ester copolymer (Formosa EVA 7320M), 10.7 parts titanium dioxide, 0.2 parts antioxidant, and 0.1 parts light stabilizer. The raw materials for the surface and middle layers of this comparative example did not include an olefin copolymer.

[0085] Comparative Example 7 Comparative Example 7 refers to the polyolefin functional adhesive film and its preparation method of Example 1, except that the amount of raw materials used in the intermediate layer is different, and the rest is the same as Example 1. The specific differences are as follows.

[0086] In Comparative Example 7, the intermediate layer materials included the following components, by weight: 89 parts polyethylene-ester copolymer (Formosa EVA 7320M), 10.7 parts titanium dioxide, 0.2 parts antioxidant, and 0.1 parts light stabilizer. The intermediate layer materials in this comparative example did not include an olefin copolymer.

[0087] Experimental example The adhesive films prepared in different embodiments and comparative examples were subjected to the following tests. The test results are shown in Table 1.

[0088] Test items: 1. Appearance Smoothness: The adhesive films prepared in different Examples and Comparative Examples were cut into small samples measuring 3 cm x 3 cm. The films were placed on a smooth surface and the height difference between the two ends of the films was measured with a ruler to reflect the degree of curl. If the height difference between the two ends was less than 1 mm, the film was considered smooth; if the height difference between the two ends was greater than or equal to 1 mm and less than 3 mm, the film was considered slightly curled; if the height difference between the two ends was greater than or equal to 3 mm, the film was considered severely curled.

[0089] 2. Tensile strength and elongation at break: Referring to GB / T 1040.3-2006 standard, the adhesive films prepared in different embodiments and comparative examples were subjected to tensile tests.

[0090] 3. Surface Heat Resistance: The adhesive films prepared in different Examples and Comparative Examples were cut into small rectangular samples measuring 2 cm x 10 cm. The samples were stretched straight with the central surface exposed to a 150°C hot steel roller for 1 second. The width (X cm) of the sample after contact with the hot steel roller was measured, and the shrinkage of the sample was calculated using the formula (2-X) / 2. If the shrinkage was less than 5%, it was considered no deformation; if the shrinkage was greater than or equal to 5% and less than 10%, it was considered slight shrinkage; if the shrinkage was greater than or equal to 10% and less than 30%, it was considered deformation; if the film shrank and melted, almost breaking or even breaking, it was considered severe deformation.

[0091] 4. Peel Strength: The adhesive films prepared in different Examples and Comparative Examples were bonded to a 150°C galvanized sheet under 0.3 MPa roller pressure to form a two-layer composite structure (adhesive film-galvanized sheet). The composite samples were cut into 25 mm × 150 mm rectangular strips and subjected to peel testing in accordance with GB / T 2790-1995.

[0092] Table 1 Test results of different adhesive films

[0093] The test results above demonstrate that the present invention, through a multilayered structure design and electron beam irradiation treatment to control the surface crosslinking degree, effectively enhances the mechanical strength and surface heat resistance of the adhesive film while maintaining the bond strength between the film and the metal material. This method is suitable for use in the field of outdoor engineering metal material protection. Furthermore, the present invention's method for preparing the polyolefin functional adhesive film is simple to operate, environmentally friendly, and cost-effective, enabling continuous industrial production.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A polyolefin functional adhesive film, characterized in that: It includes a surface layer, an intermediate layer and an inner layer stacked in sequence along the thickness direction; The surface layer comprises the following components in parts by weight: 70-80 parts of olefin copolymer, 15-30 parts of polyethylene-ester copolymer, 0.5-2 parts of crosslinking sensitizer, 0.1-0.3 parts of auxiliary crosslinking agent, 0.1-1 parts of antioxidant and 0.1-0.2 parts of light stabilizer; The intermediate layer comprises the following components in parts by weight: 40 to 50 parts of olefin copolymer, 35 to 55 parts of polyethylene-ester copolymer, 10 to 15 parts of titanium dioxide, 0.1 to 1 part of antioxidant and 0.1 to 0.2 part of light stabilizer; The inner layer comprises the following components in parts by weight: 10 to 30 parts of olefin copolymer, 40 to 70 parts of polyethylene-ester copolymer and 20 to 40 parts of maleic anhydride modified polyethylene-ester copolymer.

2. The polyolefin functional adhesive film according to claim 1, characterized in that: Has at least one of the following characteristics: (1) The olefin copolymer in the surface layer, the olefin copolymer in the middle layer, and the olefin copolymer in the inner layer are each independently selected from at least one of polyethylene-propylene copolymer, polyethylene-butene copolymer, polyethylene-octene copolymer, and amorphous α-olefin copolymer; (2) The polyethylene-ester copolymer in the surface layer, the polyethylene-ester copolymer in the middle layer, and the polyethylene-ester copolymer in the inner layer are each independently selected from at least one of polyethylene-vinyl acetate copolymer, polyethylene-methyl acrylate copolymer, polyethylene-ethyl acrylate copolymer, and polyethylene-butyl acrylate copolymer.

3. The polyolefin functional adhesive film according to claim 1 or 2, characterized in that: The olefin copolymer in the surface layer, the olefin copolymer in the middle layer, and the olefin copolymer in the inner layer are of the same type; the polyethylene-ester copolymer in the surface layer, the polyethylene-ester copolymer in the middle layer, and the polyethylene-ester copolymer in the inner layer are of the same type.

4. The polyolefin functional adhesive film according to claim 1, characterized in that: Has at least one of the following characteristics: (1) In the surface layer, the amount of the olefin copolymer is 72% to 80% of the total mass of the olefin copolymer and the polyethylene-ester copolymer; (2) In the intermediate layer, the amount of the olefin copolymer is 45% to 55% of the total mass of the olefin copolymer and the polyethylene-ester copolymer; (3) In the inner layer, the amount of the olefin copolymer is 30% to 40% of the total mass of the olefin copolymer and the polyethylene-ester copolymer.

5. The polyolefin functional adhesive film according to claim 1, characterized in that: Has at least one of the following characteristics: (1) The crosslinking sensitizer includes at least one of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butylperoxy-3,5,5-trimethylhexanoate, triallyl isocyanate, 4,4-di(tert-amylperoxy) valerate, tert-butyl peroxy-2-ethylhexyl carbonate, and ethyl 3,3-di(tert-butylperoxy)butyrate; (2) The auxiliary cross-linking agent includes at least one of tris(2-hydroxyethyl)isocyanurate triacrylate, trimethylolpropane triacrylate, triallyl cyanurate, triallyl isocyanurate, pentaerythritol triacrylate and ethoxylated trimethylolpropane triacrylate.

6. The polyolefin functional adhesive film according to claim 1, characterized in that: Has at least one of the following characteristics: (1) The maleic anhydride-modified polyethylene-ester copolymer includes at least one of a maleic anhydride-modified polyethylene-vinyl acetate copolymer, a maleic anhydride-modified polyethylene-methyl acrylate copolymer, a maleic anhydride-modified polyethylene-ethyl acrylate copolymer, and a maleic anhydride-modified polyethylene-butyl acrylate copolymer; (2) In the maleic anhydride-modified polyethylene-ester copolymer, the grafting rate of maleic anhydride is 0.5 wt % to 2 wt %.

7. The polyolefin functional adhesive film according to claim 1, characterized in that: The total thickness of the polyolefin functional adhesive film is 0.15 to 0.4 mm; The thickness of the surface layer accounts for 25% to 50% of the total thickness of the polyolefin functional adhesive film; The thickness of the intermediate layer accounts for 40% to 70% of the total thickness of the polyolefin functional adhesive film; The thickness of the inner layer accounts for 5% to 10% of the total thickness of the polyolefin functional adhesive film.

8. The method for preparing a polyolefin functional adhesive film according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: co-extruding the raw materials of the surface layer, the raw materials of the middle layer and the raw materials of the inner layer, and then subjecting the surface layer side of the film obtained by the multi-layer co-extrusion to electron beam irradiation to obtain the polyolefin functional adhesive film.

9. The preparation method according to claim 8, characterized in that In the electron beam irradiation treatment, the irradiation dose is 100 to 180 kGy.

10. Use of the polyolefin functional adhesive film according to any one of claims 1 to 7 or the polyolefin functional adhesive film prepared by the preparation method according to any one of claims 8 to 9 in the corrosion protection of outdoor metal materials.

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