Easy-to-separate film, adhesive film for flatly attaching the same, and method for manufacturing the same

Abstract

The present application relates to the technical field of high polymer adhesive, in particular to a kind of easy-to-separate film flat paste adhesive film and its preparation method and application.Easy-to-separate film flat paste adhesive film, including adhesive layer and the protective film arranged on at least one side surface of the adhesive layer;The adhesive layer includes the following components by weight fraction: 100 parts of polyester TPU, 10~30 parts of liquid butyronitrile rubber, 5~15 parts of maleic anhydride graft, 2~10 parts of silicate filler and 0.1~2 parts of antioxidant;In the maleic anhydride graft, the grafting rate of maleic anhydride is ≥0.8%;The material of the protective film is linear low density polyethylene.The flat paste adhesive film of the present application can realize the high-strength, durable bonding of flexible finishing material and rigid substrate, and the adhesive layer and protective film of flat paste adhesive film have good film separation effect, which is beneficial to efficient application in flat paste field.

Description

Technical Field

[0001] This invention relates to the field of polymer adhesives, and in particular to an easily separable flat adhesive film, its preparation method, and its application. Background Technology

[0002] In the fields of panel furniture, interior decoration, and building material cladding, flat lamination is a core surface decoration technology. This process uses a flatbed press or continuous roller press to bond flexible decorative materials (such as PVC decorative film) to rigid substrates (such as SPC boards, carbon crystal boards, MDF, engineered wood panels, and plywood) over a large area without edge covering. Its core objective is to give the substrate a beautiful, wear-resistant, scratch-resistant, easy-to-clean, and weather-resistant decorative surface, and it is widely used in the manufacture of cabinet doors, furniture panels, interior wall panels, system doors and windows, and integrated ceilings.

[0003] Currently, the market primarily employs two technical solutions for bonding flexible decorative materials to rigid substrates: solvent-based adhesives and reactive polyurethane hot melt adhesives (PUR). Solvent-based adhesives suffer from high VOC emissions, inconvenient operation, uneven adhesive layer thickness, and unstable bonding quality. PUR adhesives, after being melt-coated, react with moisture in the air and cross-link to form a strong and tough adhesive layer with high temperature and chemical resistance, effectively solving the VOC emission problem. However, PUR technology also has limitations, including stringent process conditions, a narrow operating temperature range, the need for specialized equipment and strict control, and high equipment maintenance costs. Furthermore, PUR is typically applied directly as bare adhesive strips without a protective film, and the application process is irreversible, resulting in low tolerance for misalignment and lack of physical protection and convenience.

[0004] Hot melt adhesive films, as an environmentally friendly adhesive, possess advantages such as being solvent-free, curing rapidly, having high production efficiency, and being easy to store and transport. However, traditional hot melt adhesive films such as TPU and EVA often fail to simultaneously meet the requirements of adhesive strength and reliability when used for bonding PVC decorative films to substrates, exhibiting problems such as insufficient adhesive performance and limited durability. Therefore, in the flat bonding application field, there is an urgent need to develop a hot melt adhesive film product with high adhesive strength and long-lasting adhesive reliability.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a flat-film adhesive film that is easy to separate from the protective film, its preparation method and application. The flat-film adhesive film of this invention can achieve high-strength and durable bonding of flexible decorative materials and rigid substrates. Moreover, the adhesive layer and protective film of the flat-film adhesive film have good separation effect, which is beneficial to its efficient application in the flat-film field.

[0007] To achieve the above-mentioned objectives of the present invention, a first aspect of the present invention provides a flat adhesive film that is easy to separate, comprising an adhesive layer and a protective film disposed on at least one side surface of the adhesive layer;

[0008] The adhesive layer comprises the following components by weight: 100 parts polyester TPU, 10-30 parts liquid nitrile rubber, 5-15 parts maleic anhydride graft, 2-10 parts silicate filler, and 0.1-2 parts antioxidant; wherein the maleic anhydride graft has a grafting rate ≥0.8%;

[0009] The protective film is made of linear low-density polyethylene.

[0010] In a specific embodiment of the present invention, the melting point of the polyester-type TPU is ≤100℃.

[0011] In a specific embodiment of the present invention, the liquid nitrile rubber includes at least one of carboxyl-terminated liquid nitrile rubber, hydroxyl-terminated liquid nitrile rubber, and amino-terminated liquid nitrile rubber.

[0012] In a specific embodiment of the present invention, the maleic anhydride graft includes at least one of maleic anhydride grafted SEBS and maleic anhydride grafted POE.

[0013] In a specific embodiment of the present invention, the mass ratio of the liquid nitrile rubber to the maleic anhydride graft is 1:(0.3~0.7).

[0014] In a specific embodiment of the present invention, the silicate filler includes at least one of talc powder, mica powder, kaolin, montmorillonite, and attapulgite.

[0015] In a specific embodiment of the present invention, the linear low-density polyethylene has a melt index of 1~3 g / 10 min at 190°C and 2.16 kg.

[0016] In a specific embodiment of the present invention, the thickness of the adhesive layer is 0.01~0.03mm; the thickness of the protective film is 0.02~0.05mm.

[0017] The second aspect of this invention provides a method for preparing the easily separable adhesive film provided in the first aspect, comprising the following steps:

[0018] Polyester-type TPU, liquid nitrile rubber, maleic anhydride graft, silicate filler and antioxidant are mixed in proportion, melt extruded and granulated, and then cast onto the surface of the protective film to obtain the flat adhesive film of the easily separable film.

[0019] The third aspect of the present invention provides the application of the easy-to-separate adhesive film provided in the first aspect in the flat bonding process of flexible decorative materials and rigid substrates.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] (1) The adhesive layer of the flat adhesive film of the present invention is based on polyester TPU as the main resin, which has good and stable adhesion to flexible decorative materials such as PVC decorative film; by introducing an appropriate amount of liquid nitrile rubber, the wettability and adhesion of the adhesive layer to rigid substrates such as wood are significantly enhanced, thereby improving the adhesion strength of the adhesive layer to them; at the same time, an appropriate amount of maleic anhydride graft can improve the compatibility of polyester TPU and liquid nitrile rubber, enhance the cohesive strength of the adhesive layer, and further improve the durability.

[0022] (2) By adjusting the composition of the adhesive layer of the flat adhesive film, the present invention can ensure high strength and durability of bonding between flexible decorative materials and rigid substrates, while having a good separation effect with the protective film, which is beneficial for its application in the flat adhesive field.

[0023] (3) The preparation process of the flat adhesive film of the present invention is simple and efficient, the raw materials are environmentally friendly, and it is suitable for continuous and large-scale production. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0025] The first aspect of the present invention provides a flat adhesive film that is easy to separate, comprising an adhesive layer and a protective film disposed on at least one side surface of the adhesive layer;

[0026] The adhesive layer comprises the following components by weight: 100 parts polyester TPU, 10-30 parts liquid nitrile rubber, 5-15 parts maleic anhydride graft, 2-10 parts silicate filler, and 0.1-2 parts antioxidant; wherein the maleic anhydride graft has a grafting rate ≥0.8%.

[0027] The protective film is made of linear low-density polyethylene.

[0028] The adhesive layer of the flat-applied film of the present invention uses polyester-type TPU as the main resin, which has good and stable adhesion to flexible decorative materials such as PVC decorative film. By introducing an appropriate amount of liquid nitrile rubber, the wettability and adhesion of the adhesive layer to rigid substrates such as wood are significantly enhanced, thereby improving the adhesion strength of the adhesive layer to them. At the same time, an appropriate amount of maleic anhydride graft can improve the compatibility between polyester-type TPU and liquid nitrile rubber, enhance the cohesive strength of the adhesive layer, and further improve durability.

[0029] In some embodiments, the amount of liquid nitrile rubber in the adhesive layer is 10 to 30 parts by weight, specifically 10, 12, 15, 18, 20, 22, 25, 28, 30 parts, or any combination thereof. Within this range, the amount of liquid nitrile rubber effectively enhances the wettability and adhesion of the adhesive layer to rigid substrates such as wood, and maintains good compatibility with polyester-based TPU through the synergistic effect of maleic anhydride grafts, giving the adhesive layer both excellent cohesive strength and durability. If the amount of liquid nitrile rubber is too small, the improvement in wettability and adhesion to rigid substrates such as wood will be insufficient; if the amount of liquid nitrile rubber is too large, it will not only lead to a decrease in cohesive strength but also easily cause phase separation, weakening the long-term adhesive stability of the adhesive layer.

[0030] In some embodiments, the liquid nitrile rubber includes at least one of carboxyl-terminated liquid nitrile rubber, hydroxyl-terminated liquid nitrile rubber, and amino-terminated liquid nitrile rubber. The polar end groups of this type of liquid nitrile rubber, such as carboxyl, hydroxyl, and amino groups, can form hydrogen bonds or chemical bonds with the hydroxyl groups on the wood surface, further improving the adhesive strength of the adhesive layer to the wood.

[0031] In some embodiments, the amount of maleic anhydride graft in the adhesive layer is 5 to 15 parts by weight, specifically 5, 8, 10, 12, 15 parts, or any combination thereof. The inventors of this invention discovered that when the amount of liquid nitrile rubber added exceeds 10 parts by weight, the compatibility and dispersibility of the liquid nitrile rubber in the polyester-based TPU matrix are poor. Using an appropriate amount of maleic anhydride graft can significantly improve the compatibility between the polyester-based TPU and the liquid nitrile rubber while ensuring relatively low adhesion between the graft and the protective film, thus avoiding interference with film separation. If the amount of maleic anhydride graft is too low, insufficient compatibility will prevent effective suppression of phase separation between the polyester TPU and the liquid nitrile rubber, leading to a significant decrease in cohesive strength and durability. If the amount of maleic anhydride graft is too high, it may not only cause the adhesive layer to become brittle overall but also increase the adhesion between the adhesive layer and the protective film, affecting film separation.

[0032] In some embodiments, the maleic anhydride grafting rate in the maleic anhydride graft is ≥0.8%, specifically within the range of 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.5%, 3%, or any combination thereof. Maintaining the maleic anhydride grafting rate within the above range ensures that the improvement in system compatibility is fully realized at a relatively low addition amount.

[0033] In some embodiments, the maleic anhydride graft includes at least one of maleic anhydride-grafted SEBS and maleic anhydride-grafted POE. In maleic anhydride-grafted SEBS and maleic anhydride-grafted POE, the matrix resin of the graft has a chemical structure similar to that of the liquid nitrile rubber portion, and the maleic anhydride groups can react with the polyester TPU, which is beneficial to improving the compatibility between the polyester TPU and the liquid nitrile rubber.

[0034] In some embodiments, the mass ratio of liquid nitrile rubber to maleic anhydride graft is 1:(0.3~0.7), specifically within the range of 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, or any combination thereof. This helps to ensure the compatibility, cohesive strength, and durability of the adhesive layer. If the ratio is too high, the amount of maleic anhydride graft is too low, which is not conducive to the dispersion of liquid nitrile rubber in polyester-based TPU. This not only fails to fully improve wettability and adhesion but may also lead to a decrease in cohesive strength due to phase separation. If the ratio is too low, the amount of maleic anhydride graft is too high, which may affect the overall toughness of the adhesive layer and increase the adhesion between the adhesive layer and the protective film, affecting film separation.

[0035] In some embodiments, the amount of silicate filler in the adhesive layer is 2 to 10 parts by weight, specifically 2, 3, 4, 5, 6, 7, 8, 9, 10 parts, or any combination thereof. The introduction of an appropriate amount of silicate filler can adjust the surface viscosity and hardness of the entire adhesive layer, ensuring smooth extrusion granulation and achieving a functional balance: reducing the adhesion between the adhesive layer and the protective film, improving the film separation effect, and enhancing ease of use; while not affecting the adhesion performance of the adhesive layer to PVC decorative film and substrates such as wood. If the amount of silicate filler is too low, the adjustment of the surface viscosity and hardness of the adhesive layer will be insufficient, making it difficult to achieve the goal of improving the film separation effect; if the amount of silicate filler is too high, the hardness of the adhesive layer will be too high, which is detrimental to the adhesion performance and durability of the adhesive layer.

[0036] In some embodiments, the silicate filler includes at least one of talc, mica, kaolin, montmorillonite, and attapulgite. Layered or chain-layered silicate fillers have a large specific surface area or lamellar structure, which can effectively control surface viscosity and hardness at low addition levels, improving film separation properties, thereby solving the film separation problem while ensuring excellent adhesion.

[0037] In some embodiments, the amount of antioxidant in the adhesive layer is 0.1 to 2 parts by weight, specifically 0.1, 0.3, 0.5, 1, 1.5, 2 parts, or any combination thereof. Adding antioxidants can prevent thermal oxidative degradation of polyester TPU during production and processing, thus maintaining its mechanical strength.

[0038] In some embodiments, the antioxidant includes, but is not limited to, at least one of antioxidant 1010, antioxidant 1076, antioxidant 1098, antioxidant 264, antioxidant B245, antioxidant TPP, and antioxidant TNP.

[0039] In some embodiments, the melting point of polyester-based TPU is ≤100℃, specifically a range of 100℃, 90℃, 80℃, 70℃, 60℃, 50℃, or any combination thereof. Polyester-based TPU exhibits good adhesion to PVC, and compared to polyether-based TPU, it possesses higher cohesive strength and stronger adhesion to polar substrates. Using polyester-based TPU with a melting point meeting the above conditions ensures both adhesion performance and cohesive strength while also helping to avoid heat damage to substrates such as PVC decorative films.

[0040] In some embodiments, the melt index of linear low-density polyethylene at 190°C and 2.16 kg is 1~3 g / 10 min, specifically within the range of 1 g / 10 min, 1.5 g / 10 min, 2 g / 10 min, 2.5 g / 10 min, 3 g / 10 min, or any combination thereof. Using linear low-density polyethylene with the above melt index ensures good processing fluidity, facilitating blown film production, and also provides the protective film with good strength, toughness, and heat resistance, making it easy to store, transport, cut, and align.

[0041] In some embodiments, the thickness of the adhesive layer is 0.01~0.03mm, specifically it can be a range of 0.01mm, 0.015mm, 0.02mm, 0.025mm, 0.03mm or any two of these; the thickness of the protective film is 0.02~0.05mm, specifically it can be a range of 0.02mm, 0.025mm, 0.03mm, 0.035mm, 0.04mm, 0.045mm, 0.05mm or any two of these.

[0042] The second aspect of this invention provides a method for preparing the easily separable adhesive film provided in the first aspect, comprising the following steps:

[0043] Polyester-type TPU, liquid nitrile rubber, maleic anhydride graft, silicate filler and antioxidant are mixed in proportion, melt extruded and granulated, and then cast onto the surface of the protective film to obtain a flat adhesive film that is easy to separate.

[0044] Melt extrusion granulation is a commonly used technology, which involves extruding raw materials with different formulation components in a twin-screw extruder. This part of the process involves routine adjustments. In some embodiments, the temperature of melt extrusion granulation can be 120~160℃, such as 120℃, 130℃, 140℃, 150℃, 160℃, or any combination thereof. Those skilled in the art can make routine adjustments according to the actual situation.

[0045] The granules obtained by melt extrusion granulation are cast onto the surface of a protective film using a casting machine. In some embodiments, the casting temperature can be 120~150°C, such as 120°C, 130°C, 140°C, 150°C, or any combination thereof, which can be conventionally adjusted by those skilled in the art according to actual conditions.

[0046] In some embodiments, the protective film is obtained by blown film blowing. A blown film machine is used to blow linear low-density polyethylene to obtain the protective film. Furthermore, the blowing temperature can be 150~180°C, such as 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, or any combination thereof, which can be conventionally adjusted by those skilled in the art according to actual conditions.

[0047] The third aspect of the present invention provides the application of the easy-to-separate adhesive film provided in the first aspect in the flat bonding process of flexible decorative materials and rigid substrates.

[0048] Example 1

[0049] This embodiment provides a method for preparing an easily separable, flat-adhesive film, including the following steps:

[0050] (1) Linear low-density polyethylene (Lanzhou Petrochemical 7042) with a melt index of 2 g / 10 min (190℃, 2.16Kg) was blown into a film at 160℃ in a blown film machine, pulled, and wound to obtain a protective film with a thickness of 0.03 mm.

[0051] (2) 100 parts by weight of polyester TPU granules (melting point 70℃, Shanghai Jintang Plastics Technology Co., Ltd., JT-5049), 20 parts by weight of carboxyl-terminated liquid nitrile rubber (grade CTBN 1300X13), 10 parts by weight of SEBS-MAH (American Corten FG1901, grafting rate 1.7%), 5 parts by weight of talc powder (Shangdong Duolian Chemical Co., Ltd., 14807-96-6), and 0.5 parts by weight of antioxidant 1010 are thoroughly mixed in a high-speed mixer, melt-extruded and granulated at 140℃, and then cast at 130℃ onto the protective film obtained in step (1) through a casting machine. The thickness of the adhesive layer is 0.02mm, and a flat adhesive film that is easy to separate is obtained.

[0052] Example 2

[0053] This embodiment provides a method for preparing an easily separable, flat-adhesive film, including the following steps:

[0054] (1) Linear low-density polyethylene (Daqing Petrochemical 18H10AX) with a melt index of 1 g / 10 min (190℃, 2.16Kg) was blown into a film at 170℃ in a blown film machine, pulled, and wound to obtain a protective film with a thickness of 0.02 mm.

[0055] (2) 100 parts by weight of polyester TPU granules (melting point 85℃, Shanghai Jintang Plastics Technology Co., Ltd., JT-5906), 15 parts by weight of hydroxyl-terminated liquid nitrile rubber (brand name HTBN-15), 8 parts by weight of SEBS-MAH (Formosa Plastics 7126, grafting rate 1.6%), 6 parts by weight of mica powder (Guangdong Yuanlei Powder Co., Ltd., 12001-26-2), and 0.8 parts by weight of antioxidant 1098 are thoroughly mixed in a high-speed mixer, melt-extruded and granulated at 150℃, and then cast at 140℃ onto the protective film obtained in step (1) through a casting machine. The thickness of the adhesive layer is 0.015mm, thus obtaining a flat adhesive film that is easy to separate.

[0056] Example 3

[0057] This embodiment provides a method for preparing an easily separable, flat-adhesive film, including the following steps:

[0058] (1) Linear low-density polyethylene (Yangzi Petrochemical 1802) with a melt index of 2 g / 10 min (190℃, 2.16Kg) was blown into a film at 155℃ in a blown film machine, pulled, and wound to obtain a protective film with a thickness of 0.035 mm.

[0059] (2) 100 parts by weight of polyester TPU granules (melting point 55℃, Shanghai Jintang Plastics Technology Co., Ltd., JT-5016), 12 parts by weight of amino-terminated liquid nitrile rubber (Lanzhou Petrochemical Liquid Nitrile-26), 6 parts by weight of POE-MAH (Kois Chemical W1A, grafting rate 1%), 3 parts by weight of montmorillonite (Qingdao Tengyun Chemical Technology Co., Ltd., 1318-93-0), and 1.2 parts by weight of antioxidant 1076 are thoroughly mixed in a high-speed mixer, melt-extruded and granulated at 125℃, and then cast at 120℃ onto the protective film obtained in step (1) using a casting machine. The thickness of the adhesive layer is 0.025mm, thus obtaining a flat adhesive film that is easy to separate.

[0060] Example 4

[0061] This embodiment provides a method for preparing an easily separable, flat-adhesive film, including the following steps:

[0062] (1) Linear low-density polyethylene (Mitsui SP1520 of Japan) with a melt index of 1.8 g / 10 min (190℃, 2.16Kg) was blown into a film at 165℃ in a blown film machine, pulled and wound to obtain a protective film with a thickness of 0.04 mm.

[0063] (2) 100 parts by weight of polyester TPU granules (melting point 65℃, Shanghai Jintang Plastics Technology Co., Ltd., JT-5018), 18 parts by weight of carboxyl-terminated liquid nitrile rubber (grade CTBN 1300X13), 12 parts by weight of SEBS-MAH (American Corten RP6670, grafting rate 1.1%), 8 parts by weight of talc powder (Dongguan Junyan Plastic Raw Materials Co., Ltd., Lotte GC-1150), and 1.5 parts by weight of antioxidant TPP are thoroughly mixed in a high-speed mixer, melt-extruded and granulated at 135℃, and then cast onto the protective film obtained in step (1) at 125℃ using a casting machine. The thickness of the adhesive layer is 0.03mm, thus obtaining a flat adhesive film that is easy to separate.

[0064] Example 5

[0065] This embodiment provides a method for preparing an easily separable, flat-adhesive film, including the following steps:

[0066] (1) Linear low-density polyethylene (Daqing Petrochemical 18H27DX) with a melt index of 2.7 g / 10 min (190℃, 2.16Kg) was blown into a film at 150℃ in a blown film machine, pulled, and wound to obtain a protective film with a thickness of 0.045 mm.

[0067] (2) 100 parts by weight of polyester TPU granules (melting point 80℃, Shanghai Jintang Plastics Technology Co., Ltd., JT-5012), 25 parts by weight of amino-terminated liquid nitrile rubber (brand name Lanzhou Petrochemical Liquid Nitrile-26), 15 parts by weight of POE-MAH (Anhui Xingbeida New Material Technology Co., Ltd., grafting rate 0.9%), 4 parts by weight of attapulgite (Shandong Duoju Chemical Co., Ltd., 1337-76-4), and 1 part by weight of antioxidant TNP are thoroughly mixed in a high-speed mixer, melt-extruded and granulated at 155℃, and then cast at 145℃ onto the protective film obtained in step (1) through a casting machine. The thickness of the adhesive layer is 0.01mm, and a flat adhesive film that is easy to separate is obtained.

[0068] Example 6

[0069] This embodiment provides a method for preparing an easily separable, flat-adhesive film, including the following steps:

[0070] (1) Linear low-density polyethylene (Daqing Petrochemical 9042) with a melt index of 2 g / 10 min (190℃, 2.16Kg) was blown into a film at 175℃ in a blown film machine, pulled, and wound to obtain a protective film with a thickness of 0.025 mm.

[0071] (2) 100 parts by weight of polyester TPU granules (melting point 70℃, Shanghai Jintang Plastics Technology Co., Ltd., JT-5026), 28 parts by weight of hydroxyl-terminated liquid nitrile rubber (brand name HTBN-15), 9 parts by weight of SEBS-MAH (Formosa Plastics 7131, grafting rate 1.3%), 7 parts by weight of kaolin (Shandong Polymer Chemical Co., Ltd., 1337-76-4), and 0.2 parts by weight of antioxidant B245 are thoroughly mixed in a high-speed mixer, melt-extruded and granulated at 130℃, and then cast at 130℃ onto the protective film obtained in step (1) through a casting machine. The thickness of the adhesive layer is 0.02mm, and a flat adhesive film that is easy to separate is obtained.

[0072] Example 7 group

[0073] The preparation method of the easily separable film in this set of examples refers to that of Example 1, except that the amount of carboxyl-terminated liquid nitrile rubber and SEBS-MAH is different. All other aspects are the same as in Example 1. The specific differences are as follows:

[0074] Example 7a: 22.5 parts by weight of carboxyl-terminated liquid nitrile rubber, 7.5 parts by weight of SEBS-MAH;

[0075] Example 7b: 18 parts by weight of terminal carboxyl liquid nitrile rubber, 12 parts by weight of SEBS-MAH;

[0076] Example 7c: 25 parts by weight of carboxyl-terminated liquid nitrile rubber, 5 parts by weight of SEBS-MAH;

[0077] Example 7d: 15 parts by weight of terminal carboxyl liquid nitrile rubber, 15 parts by weight of SEBS-MAH.

[0078] Comparative Example 1

[0079] Comparative Example 1 uses the same method as Example 1 for preparing the easy-to-separate film, except that carboxyl-terminated liquid nitrile rubber was not added in step (2).

[0080] Comparative Example 2

[0081] Comparative Example 2 uses the same method as Example 1 for preparing the easy-to-separate film, except that SEBS-MAH was not added in step (2).

[0082] Comparative Example 3

[0083] Comparative Example 3 refers to the preparation method of the easy-to-separate film of Example 1, except that in step (2), an equal weight of POE-MAH (Coase Chemical, grafting rate 0.6%) is used instead of SEBS-MAH.

[0084] Comparative Example 4

[0085] Comparative Example 4 uses the same method as Example 1 for preparing the easy-to-separate film, except that the amount of SEBS-MAH used in step (2) is different.

[0086] In this comparative example, the amount of SEBS-MAH used was 20 parts by weight.

[0087] Comparative Example 5

[0088] Comparative Example 5 uses the same method as Example 1 for preparing the easy-to-separate film flat adhesive film, except that talc powder was not added in step (2).

[0089] In this comparative example, during melt extrusion granulation in step (2), it was found that the components of the adhesive layer could not be successfully granulated by the twin-screw extruder.

[0090] Comparative Example 6

[0091] Comparative Example 6 uses the same method as Example 1 for preparing the easy-to-separate film, except that the amount of talc powder used in step (2) is different.

[0092] In this comparative example, the amount of talc used was 12 parts by weight.

[0093] Experimental Example

[0094] The performance of the flat adhesive films of different embodiments and comparative examples was tested as follows, and the test results are shown in Table 1.

[0095] 1. Separation performance:

[0096] The flat-applied adhesive film is separated using a film separating machine. The separation process involves taking a 50m long sample of the flat-applied adhesive film, placing it on the separating machine, setting the linear speed of the separating machine to 60m / min, starting the separating machine, and observing the separation of the protective film and adhesive layer after 1 minute. If the adhesive layer appears on the protective film or the separating machine is obstructed during the separation process, it is considered a difficult-to-separate film; conversely, if the separation is smooth, it is considered an easy-to-separate film.

[0097] 2. Peel strength

[0098] Take a flat adhesive film sample and attach the adhesive layer to different rigid substrates (SPC board, carbon crystal board, MDF). Then remove the protective film and attach a PVC decorative film to the other side of the adhesive layer. Then, hot press the film together at 100℃ and 0.2MPa for 8s to obtain PVC / SPC board, PVC / carbon crystal board, and PVC / MDF test samples respectively. According to the GB / T2790 test standard, the peel strength at 180° room temperature is tested at a peel speed of 100mm / min.

[0099] After subjecting the above-mentioned test samples to thermal cycling shock tests, the 180° peel strength after thermal cycling shocks was tested at a peel speed of 100 mm / min according to the GB / T2790 test standard. In the thermal cycling shock test, the samples were placed at -20℃ for 4 hours and then at 60℃ for 4 hours. This constitutes one cycle, and a total of 7 cycles were performed.

[0100] Table 1 Performance test results of different embodiments and comparative examples

[0101]

[0102] Note: The above peel interfaces are all between the adhesive layer and the rigid substrate. In Comparative Example 4, the peel strength could not be tested due to the difficult-to-separate film.

[0103] The flat adhesive film of this invention can achieve high-strength and durable bonding between flexible decorative materials and rigid substrates, and the adhesive layer and protective film of the flat adhesive film have good separation effect. According to the test results of Examples 1 to 6, the easily separable flat adhesive film of this invention can achieve high-strength bonding (>50N / 25mm) to PVC decorative film and rigid substrates (SPC board, carbon crystal board, MDF) with good bonding reliability (almost no decrease in peel strength after 7 cycles of thermal shock test) by appropriately proportioning the components, and the adhesive layer and protective film have good separation effect, which is convenient for downstream applications. It provides a new type of adhesive material with excellent performance, convenient operation, and environmentally friendly reliability for industries such as panel furniture and interior decoration.

[0104] According to the test results of Example 7, controlling the mass ratio of liquid nitrile rubber to maleic anhydride graft within a certain range helps to ensure the compatibility, cohesive strength, and durability of the adhesive layer. If the ratio is too large, the amount of liquid nitrile rubber used is relatively large, and the amount of maleic anhydride graft used is relatively small, which is not conducive to the dispersion of liquid nitrile rubber in polyester-type TPU, and phase separation is likely to occur, resulting in poor cohesive strength. After thermal cycling, the peel strength will decrease to a certain extent. If the ratio is too small, the amount of liquid nitrile rubber used is relatively small, and the amount of maleic anhydride graft used is relatively large, which will affect the overall toughness of the adhesive layer and reduce the peel strength after thermal cycling.

[0105] According to the test results of Example 1 and Comparative Example 1, the addition of liquid nitrile rubber can improve the wettability of the adhesive layer to the substrate, thereby improving the bonding strength of polyester TPU to the rigid substrate. According to the test results of Example 1 and Comparative Examples 2-3, the use of maleic anhydride grafts with a certain grafting rate can improve the compatibility between polyester TPU and liquid nitrile rubber, thus giving the adhesive layer good bonding reliability. According to the test results of Example 1 and Comparative Example 4, excessive maleic anhydride graft content will increase its adhesion to the protective film. According to the test results of Example 1 and Comparative Examples 5-6, an appropriate amount of silicate filler can improve the processing performance of the adhesive layer formulation and ensure a smooth extrusion granulation process; the introduction of excessive silicate filler, although facilitating film separation, results in excessively high adhesive layer hardness, which is detrimental to the adhesive layer's bonding performance and durability.

[0106] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions 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. An easily separable, flat-adhesive film, characterized in that, Includes an adhesive layer and a protective film disposed on at least one surface of the adhesive layer; The adhesive layer comprises the following components by weight: 100 parts polyester TPU, 10-30 parts liquid nitrile rubber, 5-15 parts maleic anhydride graft, 2-10 parts silicate filler, and 0.1-2 parts antioxidant; wherein the maleic anhydride graft has a grafting rate ≥0.8%; The protective film is made of linear low-density polyethylene; The mass ratio of the liquid nitrile rubber to the maleic anhydride graft is 1:(0.3~0.7). The liquid nitrile rubber includes at least one of carboxyl-terminated liquid nitrile rubber, hydroxyl-terminated liquid nitrile rubber, and amino-terminated liquid nitrile rubber. The maleic anhydride graft includes at least one of maleic anhydride-grafted SEBS and maleic anhydride-grafted POE.

2. The easy-to-separate adhesive film according to claim 1, characterized in that, The melting point of the polyester-type TPU is ≤100℃.

3. The easy-to-separate adhesive film according to claim 1, characterized in that, The silicate filler includes at least one of talc powder, mica powder, kaolin, montmorillonite, and attapulgite.

4. The easy-to-separate adhesive film according to claim 1, characterized in that, The linear low-density polyethylene has a melt index of 1~3 g / 10 min at 190℃ and 2.16 kg.

5. The easy-to-separate adhesive film according to claim 1, characterized in that, The thickness of the adhesive layer is 0.01~0.03mm; the thickness of the protective film is 0.02~0.05mm.

6. The method for preparing the easily separable film of the flat-adhesive film according to any one of claims 1 to 5, characterized in that, Includes the following steps: Polyester-type TPU, liquid nitrile rubber, maleic anhydride graft, silicate filler and antioxidant are mixed in proportion, melt extruded and granulated, and then cast onto the surface of the protective film to obtain the flat adhesive film of the easily separable film.

7. The application of the easy-separating film according to any one of claims 1 to 5 or the easy-separating film prepared by the preparation method according to claim 6 in the flat bonding process of flexible decorative materials and rigid substrates.

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