Coatable polyurethane reactive hot melt adhesive and preparation method thereof

Abstract

The invention discloses a coatable polyurethane reactive hot melt adhesive and a preparation method thereof, and belongs to the technical field of adhesives. According to the invention, polycarbonate polyol is introduced into the raw materials, a carbonate bond (-OC (O)-O-) in the polycarbonate polyol has high cohesive energy, high polarity, high adhesive strength and heat resistance of a strong ester bond (-COO-) in polyester polyol, and also has (-COC-) water resistance and flexibility of an ether bond in polyether polyol, and the other raw materials are combined, so that the flame retardant property of the flame retardant is greatly improved, and the flame retardant property of the flame retardant is greatly improved. The high bonding strength and excellent water resistance of the polyurethane reaction type hot melt adhesive are ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of adhesives, and in particular relates to a coatable polyurethane reactive hot melt adhesive and a preparation method thereof. Background Art

[0002] There are several ways to apply hot melt adhesive, including spraying, scraping, spot coating, fiber spraying, spiral spraying and roller coating. In the use of existing adhesives, the coating construction method is often more time-saving, labor-saving, glue-saving, and efficiency-enhancing than the traditional brushing construction method, achieving twice the result with half the effort. Coating is now widely used in bonding metals, plastics, wood, leather, sponges, cloth, stone, shoes and other materials.

[0003] Although relevant departments have introduced more stringent environmental protection standards and imposed strict restrictions on benzene, heavy metals, etc., the VOC emissions of solvent-based adhesives that meet environmental standard certification are still relatively large, which is different from the standard limits. Therefore, solvent-based coating adhesives that meet environmental product standards are not the most environmentally friendly adhesive products at present. In response to strong demands in the field of environmental protection, some products with backward production capacity and high content of toxic and harmful substances will be eliminated, and environmentally friendly and environmentally friendly high-functional adhesives such as hot melt and water-based adhesives will be vigorously developed. Therefore, the development of new solvent-free, completely environmentally friendly, and coatable hot melt adhesives has become an urgent requirement and priority for the progress of the times. Summary of the invention

[0004] The object of the present invention is to provide a coatable polyurethane reactive hot melt adhesive and a preparation method thereof, so as to solve the technical problems of solvent volatilization pollution and poor water resistance of traditional hot melt adhesives.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention discloses a polyurethane-coatable reactive hot melt adhesive. The raw materials of the polyurethane-coatable reactive hot melt adhesive include, by weight: 25-45 parts of crystalline polycarbonate polyol, 5-25 parts of non-crystalline polycarbonate polyol, 8-16 parts of isocyanate, 0.4-1.8 parts of silane coupling agent, 0.2-0.8 parts of catalyst and 0.1-1.0 parts of auxiliary agent.

[0006] Furthermore, the structural formula of the crystalline polycarbonate polyol is as follows: ; Wherein, n represents the number of molecules containing polycarbonate units in each molecule, and the value of n is ≥1; The crystalline polycarbonate polyol has a molecular weight of 500-3000 g / mol, a hydroxyl value of 30-350 mgKOH / g, an acid value of ≤0.1 mgKOH / g, a water content of ≤0.1 wt %, a melting point of ≤65° C., and a viscosity of 80-8000 mpa·s.

[0007] Furthermore, the structural formula of the non-crystalline polycarbonate polyol is as follows: ; The non-crystalline polycarbonate polyol has a molecular weight of 1000-3500 g / mol, a hydroxyl value of 25-45 mgKOH / g, an acid value of ≤0.1 mgKOH / g, a water content of ≤0.05 wt %, and a viscosity of 2000-5000 mpa·s.

[0008] Furthermore, the isocyanate is one or both of a diisocyanate and a polyisocyanate; the polyisocyanate is one or more of diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, naphthalene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, lysine diisocyanate and tetramethyl dimethylene diisocyanate.

[0009] Further, the silane coupling agent is one or more of 3-aminopropyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, isocyanatepropyltriethoxysilane, mercapto-protected silane coupling agent, 3-glycidyloxypropyltrimethoxysilane, 3-thiooctanoyl-1-propyltriethoxysilane, 3-[3-(trimethoxysilyl)propyl]isocyanurate and 3-isocyanatepropyltrimethoxysilane.

[0010] Further, the catalyst is at least one of dimorpholinyl diethyl ether, N-methylmorpholine, N-ethylmorpholine, triethylenediamine, N,N-dimethylbenzylamine, di(methylaminoethyl)ether, stannous isooctanoate, dibutyltin dilaurate and bismuth carboxylate catalyst; The auxiliary agent is one or more of an antioxidant, a leveling agent, a color paste, a filler and a colorant; The antioxidant is one of antioxidants 168, 1076, 1010 and 2,6-di-tert-butyl-4-methylphenol; The filler is titanium dioxide, carbon black or fumed silica.

[0011] The present invention also discloses a method for preparing the above-mentioned coatable polyurethane reactive hot melt adhesive, comprising the following steps: Weighing raw materials according to the mass fractions of claim 1 for use, pre-treating the weighed crystalline polycarbonate polyol and non-crystalline polycarbonate polyol to obtain pre-treated polycarbonate polyol; The pretreated polycarbonate polyol and isocyanate are mixed to carry out polymerization reaction to obtain -NCO terminated polyurethane hot melt adhesive prepolymer; A silane coupling agent, a catalyst and an auxiliary agent are sequentially added to a -NCO-terminated polyurethane hot melt adhesive prepolymer for a modification reaction, and a coatable polyurethane reactive hot melt adhesive is obtained after the modification reaction is completed.

[0012] Furthermore, the specific steps of the pretreatment are: Add crystalline polycarbonate polyol and non-crystalline polycarbonate polyol into a planetary stirred reactor, heat the planetary stirred reactor to completely melt them into a liquid state, start the vacuum pump, start heating at 100-140°C, maintain the vacuum degree between -0.09MPa and 0.1MPa, and stir at a rate of 50-400r / min, remove water for 1.0-2.5h to obtain pretreated polycarbonate polyol.

[0013] Furthermore, the process parameters of the polymerization reaction are: the polymerization reaction temperature is 65-95° C., the time is 1.0-3.0 h, the vacuum degree is -0.09 MPa~0.1 MPa, and the stirring rate is 100-300 r / min.

[0014] Furthermore, the process parameters for the modification reaction of adding silane coupling agent, catalyst and auxiliary agent to the -NCO terminated polyurethane hot melt adhesive prepolymer in sequence are as follows: the vacuum degree is maintained between -0.09MPa and 0.1MPa, nitrogen protection, stirring rate is 100-300r / min, the modification reaction temperature when adding silane coupling agent is 65-95°C, and the time is 0.05-1.0h; the promotion reaction temperature when adding catalyst is 65-95°C, and the time is 0.1-1.0h; the supplementary reaction temperature for performance when adding auxiliary agent is 60-90°C, and the time is 0.5-1.0h.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The invention discloses a coatable polyurethane reactive hot melt adhesive. Polycarbonate polyol is introduced into the raw materials. The carbonate bond (-OC(O)-O-) in the polycarbonate polyol has the large cohesive energy, large polarity, high adhesion and heat resistance of the strong ester bond (-COO-) in the polyester polyol, and also has the water resistance and flexibility of the ether bond (-COC-) in the polyether polyol. Combined with other raw materials, the high bonding strength and excellent water resistance of the polyurethane reactive hot melt adhesive are guaranteed. Meanwhile, no solvent is used and volatilized in the whole process of production, coating and curing, thereby ensuring safety and environmental protection. Polycarbonate polyols use crystalline polycarbonate polyols and non-crystalline polycarbonate polyols, a polyol with the same structure but two different forms, which have basically similar structures. This improves product stability and avoids poor compatibility between various polyols, tackifiers, plasticizers and other resins, uneven mixing during the melt polymerization process, inconsistent reaction rates, incomplete curing of polyurethane hot melt adhesive prepolymers, phase separation, and other quality problems that lead to reduced bonding performance, reduced water resistance, and so on.

[0016] The present invention also discloses a method for preparing the above-mentioned coatable polyurethane reactive hot melt adhesive. By adopting a solvent-free, bulk polymerization preparation process, compared with the prior art, the method has the advantages of no solvent volatilization during the curing and use process and is environmentally friendly.

[0017] Furthermore, the present invention adopts solvent-free technology to avoid the pollution caused by the use of solvent volatilization and curing. According to relevant experimental results, the prepared polyurethane hot melt adhesive is heated to 100-130°C, and the prepolymer presents a low-viscosity fluid, which can be coated on the surface of the substrate. Since the polyurethane hot melt adhesive has initial viscosity and is quickly cooled, it can be bonded with the substrate through colloid crystallization, molecular crosslinking, etc. to generate initial adhesion strength; then the substrate and the moisture on the adherend or the moisture in the surrounding environment are wet-cured and cross-linked, that is, the -NCO group in the polyurethane hot melt adhesive reacts chemically with the water molecule or other compounds containing active hydrogen to generate carbamate (NHCOO-), and then the carbamate continues to react with the (NCO) group to generate allophanate (-NHCONH-), and the urea group continues to react with the (NCO) group to generate a biuret structure. Most of the process in this stage is a chemical process, resulting in chemical curing. After the curing is completed, the final adhesion strength is formed, and finally secondary bonds, adhesion and cohesion, and covalent bonds are formed, which have high bonding strength and water resistance. The entire curing process is 100% curing and reaction curing, which avoids the generation of solvent volatilization and curing pollutants while improving the bonding strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is an infrared spectrum structure diagram of the coatable polyurethane reactive hot melt adhesive prepared by the present invention after curing; Figure 2The present invention is a graph showing the viscosity of the coatable polyurethane reactive hot melt adhesive prepared by the present invention changing with temperature at different temperatures. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0020] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0021] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0022] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0023] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0024] The present invention provides a coatable polyurethane reactive hot melt adhesive. The raw materials of the coatable polyurethane reactive hot melt adhesive include, by weight: 25-45 parts of crystalline polycarbonate polyol, 5-25 parts of non-crystalline polycarbonate polyol, 8-16 parts of isocyanate, 0.4-1.8 parts of silane coupling agent, 0.2-0.8 parts of catalyst and 0.1-1.0 parts of auxiliary agent.

[0025] Preferably, the polycarbonate polyol is 25-45 parts of crystalline polycarbonate polyol and 5-25 parts of non-crystalline polycarbonate polyol; Crystalline polycarbonate polyol can be selected from Ube's UH-50, UH-100, UH-200, UH-300, Asahi Kasei's T6001, T6002, T4692, T4691, etc. The specific parameters are: appearance: white solid, molecular weight: 500-3000g / mol, hydroxyl value: 30-350mgKOH / g, acid value: ≤0.1mg KOH / g, water content: ≤0.1wt%, melting point ≤65℃, viscosity (75℃): 80-8000mpa·s, and the structural formula is as follows: ; In the formula, n represents the number of molecules containing polycarbonate units in each molecule, n≥1, and the value of n can determine technical indicators such as the state of the polyol at room temperature, which can be adjusted according to the applicability of the product, and the present invention does not impose any specific restrictions; The non-crystalline polycarbonate polyol can be selected from one of Asahi Kasei T5652, T5651, T5650J, T5650E, T4672, T4671, G3450J, G3452, AS302, Dazhi Chemical PPCD231, PPCD232, etc. The specific parameters are: appearance: viscous liquid, molecular weight: 500-3500g / mol, hydroxyl value: 25-300mgKOH / g, acid value: ≤0.05mg KOH / g, water content: ≤0.05wt%, viscosity (40℃): 200-10000mpa·s, and the structural formula is as follows: ; Preferably, the isocyanate is a mixture of one or more diisocyanates or polyisocyanates; preferably, diphenylmethane diisocyanate (MDI), a mixture of one or more of toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), naphthalene diisocyanate (NDI), isophorone diisocyanate (IPDI), xylylene diisocyanate (XDI), lysine diisocyanate (LDI), tetramethyl dimethylene diisocyanate (TMXDI); Preferably, the silane coupling agent is a mixture of one or more of 3-aminopropyltriethoxysilane (KH550), 3-(2,3-epoxypropyloxy)propyltrimethoxysilane (KH-560), 3-glycidyloxypropyltrimethoxysilane (KH570), N-phenyl-γ-aminopropyltrimethoxysilane (Y9669), isocyanatepropyltriethoxysilane (IPTS), mercapto-protected silane coupling agent, 3-glycidyloxypropyltrimethoxysilane (A-187), 3-thiooctanoyl-1-propyltriethoxysilane (A-Link599), 3-[3-(trimethoxysilyl)propyl]isocyanurate (A-Link 597), and 3-isocyanatepropyltrimethoxysilane (A-Link 35).

[0026] Preferably, the catalyst is at least one of dimorpholinyl diethyl ether (DMDEE), N-methylmorpholine, N-ethylmorpholine, triethylenediamine, N,N-dimethylbenzylamine, di(methylaminoethyl) ether, stannous isooctanoate, dibutyltin dilaurate, or an organic bismuth catalyst.

[0027] Preferably, the additives are antioxidants 1010, 168, 1076, leveling agents BYK333, BYK302, fillers carbon black, graphite, colorants, etc.

[0028] The polyurethane reactive hot melt adhesive disclosed by the invention has a viscosity of 1000-8000 MPa·s, a bonding strength of 5.0-7.5 MPa for polycarbonate sheet (PC) and stainless steel aluminum sheet (Al), and 7.0-11.0 MPa for PC and PC, and a high water resistance. The bonding strength test still maintains more than 2.5 MPa after 1000 hours. The bonding parts of other materials (PVC, cloth, wood, etc.) are damaged during the test, which is caused by the large bonding strength between the adhesive and the substrate. The adhesive is suitable for coating and gluing, such as cloth, leather, sheet flat lamination, metal, plastic bonding and other fields.

[0029] The present invention also discloses a method for preparing the above-mentioned coatable polyurethane reactive hot melt adhesive, comprising the following steps: Weighing raw materials according to the above mass fractions for use, pre-treating the weighed crystalline polycarbonate polyol and non-crystalline polycarbonate polyol to obtain pre-treated polycarbonate polyol; The pretreated polycarbonate polyol and isocyanate are mixed to carry out polymerization reaction to obtain -NCO terminated polyurethane hot melt adhesive prepolymer; A silane coupling agent, a catalyst and an auxiliary agent are sequentially added to a -NCO-terminated polyurethane hot melt adhesive prepolymer for a modification reaction, and a coatable polyurethane reactive hot melt adhesive is obtained after the modification reaction is completed.

[0030] Preferably, the specific steps of pretreatment are: adding crystalline polycarbonate polyol and non-crystalline polycarbonate polyol to a planetary stirred reactor, heating to completely melt the raw materials in the reactor into a liquid state, turning on the vacuum pump, pretreating the raw materials, turning on the heating at 100°C-140°C, maintaining the vacuum degree between -0.09MPa and 0.1MPa, and stirring at a rate of 50-400r / min, and removing water for 1.0-2.5h.

[0031] Preferably, the process parameters of the polymerization reaction are: the polymerization reaction temperature is 65-95° C., the reaction time is 1.0-3.0 h, the vacuum degree is maintained between -0.09 MPa and 0.1 MPa, and the stirring rate is 100-300 r / min.

[0032] Preferably, in the modification reaction, the vacuum degree is maintained between -0.09MPa and 0.1MPa throughout the process, nitrogen protection is provided, the stirring rate is 100-300r / min, the modification reaction temperature when the silane coupling agent is added is 65-95°C, and the time is 0.05-1.0h; the promotion reaction temperature when the catalyst is added is 65-95°C, and the time is 0.1-1.0h; the supplementary reaction temperature for performance when the auxiliary agent is added is 60-90°C, and the time is 0.5-1.0h.

[0033] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0034] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0035] Example 1 A method for preparing a coatable polyurethane reactive hot melt adhesive comprises the following steps: S1: According to weight, weigh 45 parts of polycarbonate polyol (UH200, crystalline polycarbonate polyol), 5 parts of polycarbonate polyol (PPCD232, non-crystalline polycarbonate polyol), 13.24 parts of diisocyanate (diphenylmethane diisocyanate), 0.80 parts of silane coupling agent (A-Link 597), 0.55 parts of catalyst (DMDEE) and 0.10 parts of antioxidant (1010); S2: adding crystalline polycarbonate polyol and non-crystalline polycarbonate polyol into a planetary stirred reactor, heating at 100°C to completely melt the raw materials in the reactor into a liquid state, starting a vacuum pump and stirring, and removing water from the raw materials. The vacuum degree is maintained between -0.09MPa and 0.1MPa, and the stirring rate is 350r / min. Water is removed for 1.5h to obtain a pretreated polycarbonate polyol; S3: cool the pretreated polycarbonate polyol to 75°C, turn off the vacuum, add isocyanate, react at 75°C for 10 minutes, turn on the vacuum, protect with nitrogen, and carry out polymerization for 1-2 hours at a stirring rate of 250r / min. During the reaction, compare the actual reaction progress with the designed theoretical value, take samples to test the diisocyanate (-NCO) content, and use the di-n-butylamine method to test the content of diisocyanate groups in polyurethane prepolymers according to HG / T 2409-1992. The actual value is close to the theoretical value, and the reaction is basically at the end point, to obtain a -NCO-terminated polyurethane hot melt adhesive prepolymer; S4: Add the silane coupling agent to the -NCO-terminated polyurethane hot melt adhesive prepolymer, and modify the prepolymer under nitrogen protection, stirring rate of 250r / min, and temperature of 75°C for 0.05h to obtain the modified prepolymer; then add the weighed catalyst to the modified prepolymer, and mix and react for 0.5h under nitrogen protection, stirring rate of 250r / min, and temperature of 75°C to obtain the polyurethane hot melt adhesive; then, according to the needs, add the antioxidant (1010) to the polyurethane hot melt adhesive, and mix and react for 0.5h under nitrogen protection, stirring rate of 300r / min, and temperature of 75°C to supplement other properties; finally, press the prepared polyurethane hot melt adhesive product from the reactor into a hose / aluminum foil bag, and seal it in vacuum or by filling it with nitrogen to obtain a coatable polyurethane reactive hot melt adhesive.

[0036] Example 2 A method for preparing a coatable polyurethane reactive hot melt adhesive comprises the following steps: S1: According to weight, weigh 40 parts of polycarbonate polyol (UH200, crystalline polycarbonate polyol), 10 parts of polycarbonate polyol (PPCD232, non-crystalline polycarbonate polyol), 13.21 parts of diisocyanate (diphenylmethane diisocyanate), 0.80 parts of silane coupling agent (A-Link 597), 0.55 parts of catalyst (DMDEE) and 0.10 parts of auxiliary antioxidant (1010); S2: adding crystalline polycarbonate polyol and non-crystalline polycarbonate polyol into a planetary stirred reactor, heating at 100°C to completely melt the raw materials in the reactor into a liquid state, starting a vacuum pump and stirring, and removing water from the raw materials. The vacuum degree is maintained between -0.09MPa and 0.1MPa, and the stirring rate is 350r / min. Water is removed for 1.5h to obtain a pretreated polycarbonate polyol; S3: cool the pretreated polycarbonate polyol to 80°C, turn off the vacuum, add isocyanate, react at 80°C for 10 minutes, turn on the vacuum, protect with nitrogen, and carry out polymerization for 1-2 hours at a stirring rate of 250r / min. During the reaction, compare the actual reaction progress with the designed theoretical value, take samples to test the diisocyanate (-NCO) content, and use the di-n-butylamine method according to HG / T 2409-1992 "Determination of Isocyanate Group Content in Polyurethane Prepolymers". The actual value is close to the theoretical value, and the reaction basically reaches the end point, obtaining a -NCO-terminated polyurethane hot melt adhesive prepolymer; S4: Add the silane coupling agent to the -NCO-terminated polyurethane hot melt adhesive prepolymer, and modify the prepolymer under nitrogen protection, stirring rate of 250r / min, and temperature of 80°C for 0.5h to obtain a modified prepolymer; then add the weighed catalyst to the modified prepolymer, mix and react for 0.5h under nitrogen protection, stirring rate of 250r / min, and temperature of 75°C to obtain a polyurethane hot melt adhesive; then, according to needs, add an antioxidant (1010) to the polyurethane hot melt adhesive, mix and react for 0.5h under nitrogen protection, stirring rate of 300r / min, and temperature of 90°C to supplement other properties; finally, press the prepared polyurethane hot melt adhesive product from the reactor into a hose / aluminum foil bag, vacuum or fill with nitrogen to seal and store, and obtain a coatable polyurethane reactive hot melt adhesive.

[0037] Example 3 A method for preparing a coatable polyurethane reactive hot melt adhesive comprises the following steps: S1: by weight, polycarbonate polyol (UH200, crystalline polycarbonate polyol) 35 parts, polycarbonate polyol (PPCD232, non-crystalline polycarbonate polyol) 15 parts, diisocyanate (diphenylmethane diisocyanate) 12.8 parts, silane coupling agent (A-Link 597) 0.80 parts, catalyst (DMDEE) 0.55 parts and auxiliary agent carbon black 0.20 parts; S2: adding crystalline polycarbonate polyol and non-crystalline polycarbonate polyol into a planetary stirred reactor, heating at 110°C to completely melt the raw materials in the reactor into a liquid state, starting a vacuum pump and stirring, and removing water from the raw materials. The vacuum degree is maintained between -0.09MPa and 0.1MPa, and the stirring rate is 350r / min. Water is removed for 1.5h to obtain a pretreated polycarbonate polyol; S3: cool the pretreated polycarbonate polyol to 75°C, turn off the vacuum, add isocyanate, react at 75°C for 10 minutes, turn on the vacuum, protect with nitrogen, and carry out polymerization for 1-2 hours at a stirring rate of 250r / min. During the reaction, compare the actual reaction progress with the designed theoretical value, take samples to test the diisocyanate (-NCO) content, and use the di-n-butylamine method to test the content of diisocyanate groups in polyurethane prepolymers according to HG / T 2409-1992. The actual value is close to the theoretical value, and the reaction is basically at the end point, to obtain a -NCO-terminated polyurethane hot melt adhesive prepolymer; S4: Add the silane coupling agent into the -NCO terminated polyurethane hot melt adhesive prepolymer, and modify the prepolymer under nitrogen protection, stirring rate of 250r / min, and temperature of 75°C for 0.5h to obtain the modified prepolymer; then add the weighed catalyst into the modified prepolymer, and mix and react for 1.0h under nitrogen protection, stirring rate of 250r / min, and temperature of 75°C to obtain the polyurethane hot melt adhesive; thereafter, according to the needs, add the auxiliary agent carbon black for modification, and add it to the polyurethane hot melt adhesive, and mix and react for 0.5h under nitrogen protection, stirring rate of 300r / min, and temperature of 75°C to supplement other properties; finally, press the prepared polyurethane hot melt adhesive product from the reactor into a hose / aluminum foil bag, and seal it in vacuum or by filling it with nitrogen to obtain a coatable polyurethane reactive hot melt adhesive.

[0038] Example 4 A method for preparing a coatable polyurethane reactive hot melt adhesive comprises the following steps: S1: by weight, 30 parts of polycarbonate polyol (UH200, crystalline polycarbonate polyol), 20 parts of polycarbonate polyol (PPCD232, non-crystalline polycarbonate polyol), 12.5 parts of diisocyanate (diphenylmethane diisocyanate), 0.80 parts of silane coupling agent (A-Link 597), 0.55 parts of catalyst (DMDEE) and 0.20 parts of auxiliary carbon black; S2: adding crystalline polycarbonate polyol and non-crystalline polycarbonate polyol into a planetary stirred reactor, heating at 115°C to completely melt the raw materials in the reactor into a liquid state, starting a vacuum pump and stirring, and removing water from the raw materials. The vacuum degree is maintained between -0.09MPa and 0.1MPa, and the stirring rate is 350r / min. Water is removed for 1.5h to obtain a pretreated polycarbonate polyol; S3: cool the pretreated polycarbonate polyol to 75°C, turn off the vacuum, add isocyanate, react at 75°C for 10 minutes, turn on the vacuum, protect with nitrogen, and carry out polymerization for 1-2 hours at a stirring rate of 250r / min. During the reaction, compare the actual reaction progress with the designed theoretical value, take samples to test the diisocyanate (-NCO) content, and use the di-n-butylamine method to test the content of diisocyanate groups in polyurethane prepolymers according to HG / T 2409-1992. The actual value is close to the theoretical value, and the reaction is basically at the end point, to obtain a -NCO-terminated polyurethane hot melt adhesive prepolymer; S4: Add the silane coupling agent into the -NCO terminated polyurethane hot melt adhesive prepolymer, and modify the prepolymer under nitrogen protection, stirring rate of 250r / min, and temperature of 75°C for 1.0h to obtain the modified prepolymer; then add the weighed catalyst into the modified prepolymer, and mix and react for 0.5h under nitrogen protection, stirring rate of 250r / min, and temperature of 75°C to obtain the polyurethane hot melt adhesive; thereafter, according to the needs, add the auxiliary agent carbon black for modification, and add it to the polyurethane hot melt adhesive, and mix and react for 0.5h under nitrogen protection, stirring rate of 300r / min, and temperature of 75°C to supplement other properties; finally, press the prepared polyurethane hot melt adhesive product from the reactor into a rubber hose / aluminum foil bag, and seal it in vacuum or by filling it with nitrogen to obtain a coatable polyurethane reactive hot melt adhesive.

[0039] Example 5 A method for preparing a coatable polyurethane reactive hot melt adhesive comprises the following steps: S1: by weight, polycarbonate polyol (UH200, crystalline polycarbonate polyol) 25 parts, polycarbonate polyol (PPCD232, non-crystalline polycarbonate polyol) 25 parts, diisocyanate (diphenylmethane diisocyanate) 12.2 parts, silane coupling agent (A-Link 597) 0.80 parts, catalyst (DMDEE) 0.55 parts and auxiliary agent titanium dioxide 0.60 parts; S2: adding crystalline polycarbonate polyol and non-crystalline polycarbonate polyol into a planetary stirred reactor, heating at 110°C to completely melt the raw materials in the reactor into a liquid state, starting a vacuum pump and stirring, and removing water from the raw materials. The vacuum degree is maintained between -0.09MPa and 0.1MPa, and the stirring rate is 350r / min. Water is removed for 1.5h to obtain a pretreated polycarbonate polyol; S3: cool the pretreated polycarbonate polyol to 75°C, turn off the vacuum, add isocyanate, react at 75°C for 10 minutes, turn on the vacuum, protect with nitrogen, and carry out polymerization for 2-3 hours at a stirring rate of 250r / min. During the reaction, compare the actual reaction progress with the designed theoretical value, take samples to test the diisocyanate (-NCO) content, and use the di-n-butylamine method according to HG / T 2409-1992 "Determination of Isocyanate Group Content in Polyurethane Prepolymers". The actual value is close to the theoretical value, and the reaction basically reaches the end point, obtaining a -NCO-terminated polyurethane hot melt adhesive prepolymer; S4: Add the silane coupling agent into the -NCO terminated polyurethane hot melt adhesive prepolymer, and modify the prepolymer under nitrogen protection, stirring rate of 250r / min, and temperature of 75°C for 1.0h to obtain the modified prepolymer; then add the weighed catalyst into the modified prepolymer, and mix and react for 1.0h under nitrogen protection, stirring rate of 250r / min, and temperature of 75°C to obtain the polyurethane hot melt adhesive; thereafter, according to the needs, add the auxiliary titanium dioxide for modification, and add it to the polyurethane hot melt adhesive, and mix and react for 0.5h under nitrogen protection, stirring rate of 300r / min, and temperature of 75°C to supplement other properties; finally, press the prepared polyurethane hot melt adhesive product from the reactor into a hose / aluminum foil bag, and seal it in vacuum or by filling it with nitrogen to obtain a coatable polyurethane reactive hot melt adhesive.

[0040] Example 6 A method for preparing a coatable polyurethane reactive hot melt adhesive comprises the following steps: S1: According to weight, weigh 40 parts of polycarbonate polyol (UH200, crystalline polycarbonate polyol), 10 parts of polycarbonate polyol (PPCD232, non-crystalline polycarbonate polyol), 8 parts of diisocyanate (diphenylmethane diisocyanate), 1.80 parts of silane coupling agent (A-Link 597), 0.20 parts of catalyst (DMDEE) and 1.00 parts of auxiliary leveling agent (BYK333); S2: adding crystalline polycarbonate polyol and non-crystalline polycarbonate polyol into a planetary stirred reactor, heating at 110°C to completely melt the raw materials in the reactor into a liquid state, starting a vacuum pump and stirring, and removing water from the raw materials. The vacuum degree is maintained between -0.09MPa and 0.1MPa, and the stirring rate is 350r / min. Water is removed for 1.5h to obtain a pretreated polycarbonate polyol; S3: cool the pretreated polycarbonate polyol to 75°C, turn off the vacuum, add isocyanate, react at 75°C for 10 minutes, turn on the vacuum, protect with nitrogen, and carry out polymerization for 1-2 hours at a stirring rate of 250r / min. During the reaction, compare the actual reaction progress with the designed theoretical value, take samples to test the diisocyanate (-NCO) content, and use the di-n-butylamine method to test the content of diisocyanate groups in polyurethane prepolymers according to HG / T 2409-1992. The actual value is close to the theoretical value, and the reaction is basically at the end point, to obtain a -NCO-terminated polyurethane hot melt adhesive prepolymer; S4: Add the silane coupling agent into the -NCO terminated polyurethane hot melt adhesive prepolymer, and modify the prepolymer under the conditions of nitrogen protection, stirring rate of 250r / min and temperature of 75°C for 0.5h to obtain the modified prepolymer; then add the weighed catalyst into the modified prepolymer, and mix and react for 0.5h under the conditions of nitrogen protection, stirring rate of 250r / min and temperature of 75°C to obtain the polyurethane hot melt adhesive; thereafter, according to the needs, add the leveling agent BYK333 into the polyurethane hot melt adhesive, and mix and react for 0.5h under the conditions of nitrogen protection, stirring rate of 300r / min and temperature of 75°C to supplement other properties; finally, press the prepared polyurethane hot melt adhesive product from the reactor into a hose / aluminum foil bag, and seal it in vacuum or by filling it with nitrogen to obtain a coatable polyurethane reactive hot melt adhesive.

[0041] Example 7 A method for preparing a coatable polyurethane reactive hot melt adhesive comprises the following steps: S1: According to weight, weigh 30 parts of polycarbonate polyol (UH200, crystalline polycarbonate polyol), 20 parts of polycarbonate polyol (PPCD232, non-crystalline polycarbonate polyol), 16 parts of diisocyanate (diphenylmethane diisocyanate), 0.40 parts of silane coupling agent (A-Link 597), 0.80 parts of catalyst (DMDEE) and 0.10 parts of auxiliary agent (red paste); S2: adding crystalline polycarbonate polyol and non-crystalline polycarbonate polyol into a planetary stirred reactor, heating at 110°C to completely melt the raw materials in the reactor into a liquid state, starting a vacuum pump and stirring, and removing water from the raw materials. The vacuum degree is maintained between -0.09MPa and 0.1MPa, and the stirring rate is 350r / min. Water is removed for 1.5h to obtain a pretreated polycarbonate polyol; S3: The pretreated polycarbonate polyol was cooled to 75°C, the vacuum was turned off, isocyanate was added, and the reaction was carried out at a temperature of 75°C for 10 minutes. The polymerization reaction was carried out for 1-2 hours under vacuum, nitrogen protection, and a stirring rate of 250 r / min. The actual reaction progress was compared with the designed theoretical value during the reaction, and the diisocyanate (-NCO) content was tested by sampling. The test was carried out using the di-n-butylamine method, referring to HG / T 2409-1992 "Determination of Isocyanate Group Content in Polyurethane Prepolymers". The actual value was close to the theoretical value, and the reaction basically reached the end point, and a -NCO-terminated polyurethane hot melt adhesive prepolymer was obtained; S4: Add the silane coupling agent to the -NCO-terminated polyurethane hot melt adhesive prepolymer, and modify the prepolymer under nitrogen protection, stirring rate of 250r / min, and temperature of 75°C for 0.5h to obtain the modified prepolymer; then add the weighed catalyst to the modified prepolymer, and mix and react for 0.5h under nitrogen protection, stirring rate of 250r / min, and temperature of 75°C to obtain the polyurethane hot melt adhesive; then, according to the needs, add some color paste to the polyurethane hot melt adhesive, and mix and react for 0.5h under nitrogen protection, stirring rate of 300r / min, and temperature of 75°C to supplement other properties. Finally, press the prepared polyurethane hot melt adhesive product from the reactor into a hose / aluminum foil bag, and seal it in vacuum or fill it with nitrogen for storage Example 8 A method for preparing a coatable polyurethane reactive hot melt adhesive comprises the following steps: S1: Weigh 45 parts of polycarbonate polyol (UH200, crystalline polycarbonate polyol), 5 parts of polycarbonate polyol (PPCD232, non-crystalline polycarbonate polyol), 8.0 parts of diisocyanate (diphenylmethane diisocyanate), 1.00 parts of silane coupling agent (A-Link 597), 0.20 parts of catalyst (DMDEE) and 0.50 parts of fumed silica by weight; S2: adding crystalline polycarbonate polyol and non-crystalline polycarbonate polyol into a planetary stirred reactor, heating at 100°C to completely melt the raw materials in the reactor into a liquid state, starting a vacuum pump and stirring, and removing water from the raw materials. The vacuum degree is maintained between -0.09MPa and 0.1MPa, and the stirring rate is 350r / min. Water is removed for 1.5h to obtain a pretreated polycarbonate polyol; S3: cool the pretreated polycarbonate polyol to 75°C, turn off the vacuum, add isocyanate, react at 75°C for 10 minutes, turn on the vacuum, protect with nitrogen, and carry out polymerization for 1-2 hours at a stirring rate of 250r / min. During the reaction, compare the actual reaction progress with the designed theoretical value, take samples to test the diisocyanate (-NCO) content, and use the di-n-butylamine method to test the content of diisocyanate groups in polyurethane prepolymers according to HG / T 2409-1992. The actual value is close to the theoretical value, and the reaction is basically at the end point, to obtain a -NCO-terminated polyurethane hot melt adhesive prepolymer; S4: Add the silane coupling agent to the -NCO-terminated polyurethane hot melt adhesive prepolymer, and modify the prepolymer under nitrogen protection, stirring rate of 250r / min, and temperature of 75°C for 0.5h to obtain the modified prepolymer; then add the weighed catalyst to the modified prepolymer, and mix and react for 0.5h under nitrogen protection, stirring rate of 250r / min, and temperature of 75°C to obtain the polyurethane hot melt adhesive; thereafter, according to demand, add fumed silica to the polyurethane hot melt adhesive, and mix and react for 0.5h under nitrogen protection, stirring rate of 300r / min, and temperature of 75°C to supplement other properties; finally, press the prepared polyurethane hot melt adhesive product from the reactor into a hose / aluminum foil bag, and seal it in vacuum or by filling it with nitrogen to obtain a coatable polyurethane reactive hot melt adhesive.

[0042] Comparative Example 1 S1: According to weight, weigh 45 parts of polycarbonate polyol (UH200, crystalline polycarbonate polyol), 5 parts of thermoplastic acrylate (BR113), 13.21 parts of diisocyanate (diphenylmethane diisocyanate), 0.80 parts of silane coupling agent (A-Link 597), 0.55 parts of catalyst (DMDEE) and 0.50 parts of antioxidant (1010); Add it into a planetary stirred reactor, turn on the heating at 110°C to completely melt the raw materials in the reactor into a liquid, turn on the vacuum pump and stir, and dewater the raw material mixture. Maintain the vacuum degree between -0.09MPa and 0.1MPa, and remove water for 1.5 hours at a stirring rate of 350r / min to obtain a dehydrated raw material mixture.

[0043] S2: polymerization reaction, the raw material after the water removal treatment in step S1 is cooled to 75°C, the vacuum is turned off, and isocyanate is added to the raw material after the water removal in step S1, and the reaction is carried out at a temperature of 75°C for 10 minutes. The vacuum is turned on, nitrogen protection is applied, and the polymerization reaction is carried out at a stirring rate of 250 r / min for 1-2 hours. During the reaction, the actual reaction progress is compared with the designed theoretical value, and the diisocyanate (-NCO) content is tested by sampling. The test adopts the di-n-butylamine method, and refers to HG / T 2409-1992 "Determination of the Isocyanate Group Content in Polyurethane Prepolymer". The actual value is close to the theoretical value, and the reaction basically reaches the end point to obtain a polyurethane prepolymer.

[0044] S3: modification reaction, adding silane coupling agent to the prepolymer in step 2, modifying the prepolymer for 0.5h under nitrogen protection, stirring rate of 250r / min, and temperature of 75°C to obtain a modified prepolymer; then adding the weighed catalyst to the modified prepolymer, mixing and reacting for 0.5h under nitrogen protection, stirring rate of 250r / min, and temperature of 75°C to obtain a polyurethane hot melt adhesive product; then, according to demand, adding some antioxidants (1010) to the polyurethane hot melt adhesive, mixing and reacting for 0.5h under nitrogen protection, stirring rate of 300r / min, and temperature of 75°C to supplement other properties. Finally, the prepared polyurethane hot melt adhesive product is pressed from the reactor into a hose / aluminum foil bag, vacuumed or filled with nitrogen to seal and store, and obtain a hot melt adhesive.

[0045] Comparative Example 2 S1: According to weight, weigh 35 parts of polycarbonate polyol (UH200, crystalline polycarbonate polyol), 15 parts of polyether polyol (PPG2000), 13.21 parts of diisocyanate (diphenylmethane diisocyanate), 0.80 parts of silane coupling agent (A-Link 597), 0.55 parts of catalyst (DMDEE) and 0.50 parts of fumed silica; Add the mixture into a planetary stirring reactor, turn on the heating at 110°C to completely melt the raw materials in the reactor into a liquid state, turn on the vacuum pump, and remove water from the raw material mixture. The vacuum degree is maintained between -0.09MPa and 0.1MPa, and the stirring rate is 350r / min. Remove water for 1.5h to obtain a raw material mixture after dehydration. S2: polymerization reaction, the raw material after the water removal treatment in step S1 is cooled to 75°C, the vacuum is turned off, the isocyanate is added to the raw material after the water removal in step S1, the reaction is carried out at a temperature of 75°C for 10 minutes, the vacuum is turned on, nitrogen protection is applied, and the polymerization reaction is carried out at a stirring rate of 250r / min for 1-2 hours. During the reaction, the actual reaction progress is compared with the designed theoretical value, and the diisocyanate (-NCO) content is tested by sampling. The test adopts the di-n-butylamine method, and refers to HG / T 2409-1992 "Determination of Isocyanate Group Content in Polyurethane Prepolymer". The actual value is close to the theoretical value, and the reaction basically reaches the end point, thereby obtaining a polyurethane prepolymer; S3: Modification reaction, add silane coupling agent to the prepolymer in step 2, and carry out modification reaction on the prepolymer for 0.5h under nitrogen protection, stirring rate of 250r / min, and temperature of 75℃ to obtain modified prepolymer; then add the weighed catalyst to the modified prepolymer, and mix and react for 0.5h under nitrogen protection, stirring rate of 250r / min, and temperature of 75℃ to obtain polyurethane hot melt adhesive product; then, according to demand, add some fumed silica to the polyurethane hot melt adhesive, and mix and react for 0.5h under nitrogen protection, stirring rate of 300r / min, and temperature of 75℃ to supplement other properties. Finally, press the prepared polyurethane hot melt adhesive product from the reactor into a hose / aluminum foil bag, vacuum or fill with nitrogen to seal and store, and obtain hot melt adhesive.

[0046] Test sample preparation: After melting the different hot melt adhesives prepared in Examples 1 to 5 and Comparative Examples 1 to 2 at 100°C, a glue coating machine was used to coat, laminate, and hold pressure on aluminum plates (Al), polycarbonate plates (PC), and polyvinyl chloride (PVC) materials, etc.; the final bonding strength was measured after curing for 72 hours in a constant temperature and humidity test chamber (25°C, 56% RH). The test of the embodiments of the present invention mainly uses aluminum plates and carbonate plates, which are difficult to bond to metal substrates. The aluminum plates have high bonding strength, and other materials such as non-woven fabrics, PP, ABS, wood boards, and foams can be easily bonded and have high bonding strength.

[0047] Performance Test: Strength test: On a tensile and compression testing machine, the test was conducted at a tensile speed of 10 mm / min according to GB / T7124-2008, and the maximum bonding force / bonding area when the bonding part of the substrate component was damaged was tested, that is, the bonding strength (P=F / S, S=l*d, l is the length of the bonding part of the substrate, d is the width of the bonding part of the substrate). The melt viscosity was tested according to GB / T10247-2008, and the water resistance was tested according to GB / T7124-2008 (the sample was completely immersed in water for 1000 hours and then tested). The tensile shear strength of the sample was shown in Table 1. As can be seen from Table 1, the coatable polyurethane reactive hot melt adhesive of the present invention uses polycarbonate polyol, has low viscosity, can be coated, and has excellent comprehensive performances such as excellent bonding strength, high and low temperature resistance, and high water resistance that can achieve 1000 hours. From the comparison between the embodiment and comparative example 1-comparative example 2, it can be seen that the addition of tackifying resin leads to a decrease in bonding strength, an increase in viscosity, and a decrease in water resistance. The viscosity of the coating glue is too large and the fluidity is poor, making it difficult to apply glue and impossible to apply evenly. The tackifying resin is mixed with the polycarbonate polyol to form a prepolymer, which causes microscopic phase separation during the prepolymerization reaction. It is not cured to form chemical bonds during the moisture curing process, resulting in a serious decrease in water resistance. Although the polyether polyol has excellent flexibility and water resistance, the ether bond strength is low, the cohesive force between the cured products is small, and the chemical cross-linking bonds formed with the surface of the substrate are also reduced, so the strength of the bonding substrate is always reduced. In short, the coatable polyurethane hot melt adhesive prepared by polycarbonate polyol has great sizing and performance advantages.

[0048] Table 1 Test results of different hot melt adhesive related properties in Example 1-Example 5 and Comparative Example 1-Comparative Example 2

[0049] The microstructure of the polyurethane reactive hot melt adhesive coated in Example 1 after curing was tested. Figure 1 As shown in the infrared spectrum structure diagram, through the comparison of special functional groups, it is shown that the glue has been completely cured to form an ideal valence bond, thereby generating strong cohesive energy and mechanical strong bonds, and finally forming an adhesive with high water resistance and high strength.

[0050] The viscosity of the coatable polyurethane reactive hot melt adhesive in Example 2 was tested at different temperatures. Figure 2 As shown in the figure, the viscosity of the glue varies with the temperature at different temperatures. Because the present invention has a wide range of applications, and the viscosity of the coating glue has a great influence on the coating, sizing and other processes, the viscosity of a glue at different temperatures is tested. The test shows that the viscosity of the glue is different at different temperatures, and the melt viscosity can be adjusted by temperature to meet the viscosity requirements of different coatings, and can be applied to different substrates. In short, the hot melt adhesive of the present invention can be used for coating.

[0051] The polymerization reaction principle of the present invention is: polyol and isocyanate are in a certain molar ratio, under certain conditions, the isocyanate group and the hydroxyl compound undergo addition polymerization reaction to generate a polyurethane reactive hot melt adhesive prepolymer (isocyanate group-terminated prepolymer); curing mechanism: the polyurethane reactive hot melt adhesive is a prepolymer with (-NCO) group as the end group, which is heated and melted and coated between the adherend and the substrate, first cooled and cured to form a certain initial adhesion; then moisture curing and crosslinking are carried out by moisture on the substrate and the adherend or the moisture in the surrounding environment, that is, the polyurethane hot melt adhesive is a prepolymer with (-NCO) group as the end group. The -NCO group in the melt reacts chemically with water molecules or other compounds containing active hydrogen to generate carbamate groups (-NHCOO-), and then the carbamate continues to react with the (-NCO) group to generate allophanate (-NHCONH-), and the group continues to react with the (-NCO) group to generate a biuret structure, so it can be inferred that a solidified product with an increasingly complex cross-linked network structure can be formed in sequence; after curing, there are three main types of bonding bonds in the polyurethane reactive hot melt adhesive, namely, secondary bonds, adhesion and cohesion, and covalent bonds, which generate strength. It can also be seen from the entire curing process that the present invention is a solvent-free, environmentally friendly reactive hot melt adhesive.

[0052] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A polyurethane reactive hot melt adhesive capable of being coated, characterized in that: The raw materials for applying the polyurethane reactive hot melt adhesive include, by weight: 25-45 parts of crystalline polycarbonate polyol, 5-25 parts of non-crystalline polycarbonate polyol, 8-16 parts of isocyanate, 0.4-1.8 parts of silane coupling agent, 0.2-0.8 parts of catalyst and 0.1-1.0 parts of auxiliary agent.

2. A coatable polyurethane reactive hot melt adhesive according to claim 1, characterized in that: The structural formula of the crystalline polycarbonate polyol is shown below: ； Wherein, n represents the number of molecules containing polycarbonate units in each molecule, and the value of n is ≥1; The crystalline polycarbonate polyol has a molecular weight of 500-3000 g / mol, a hydroxyl value of 30-350 mgKOH / g, an acid value of ≤0.1 mgKOH / g, a water content of ≤0.1 wt %, a melting point of ≤65° C., and a viscosity of 80-8000 mpa·s.

3. The coatable polyurethane reactive hot melt adhesive according to claim 1, characterized in that: The structural formula of the non-crystalline polycarbonate polyol is as follows: ； The non-crystalline polycarbonate polyol has a molecular weight of 1000-3500 g / mol, a hydroxyl value of 25-45 mgKOH / g, an acid value of ≤0.1 mgKOH / g, a water content of ≤0.05 wt %, and a viscosity of 2000-5000 mpa·s.

4. The coatable polyurethane reactive hot melt adhesive according to claim 1, characterized in that: The isocyanate is one or both of diisocyanate and polyisocyanate; the polyisocyanate is one or more of diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, naphthalene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, lysine diisocyanate and tetramethyl dimethylene diisocyanate.

5. The coatable polyurethane reactive hot melt adhesive according to claim 1, characterized in that: The silane coupling agent is one or more of 3-aminopropyl triethoxysilane, 3-(2,3-epoxypropyloxy)propyl trimethoxysilane, 3-glycidyloxypropyl trimethoxysilane, N-phenyl-γ-aminopropyl trimethoxysilane, isocyanate propyl triethoxysilane, mercapto protected silane coupling agent, 3-glycidyloxypropyl trimethoxysilane, 3-thiooctanoyl-1-propyl triethoxysilane, 3-[3-(trimethoxysilyl)propyl]isocyanurate and 3-isocyanate propyl trimethoxysilane.

6. The coatable polyurethane reactive hot melt adhesive according to claim 1, characterized in that: The catalyst is at least one of dimorpholinyl diethyl ether, N-methylmorpholine, N-ethylmorpholine, triethylenediamine, N,N-dimethylbenzylamine, di(methylaminoethyl)ether, stannous isooctanoate, dibutyltin dilaurate and bismuth carboxylate catalysts; The auxiliary agent is one or more of an antioxidant, a leveling agent, a color paste, a filler and a colorant; The antioxidant is one of antioxidants 168, 1076, 1010 and 2,6-di-tert-butyl-4-methylphenol; The filler is titanium dioxide, carbon black or fumed silica.

7. A method for preparing a coatable polyurethane reactive hot melt adhesive according to any one of claims 1 to 6, characterized in that: The following steps are involved: Weighing raw materials according to the mass fractions of claim 1 for use, pre-treating the weighed crystalline polycarbonate polyol and non-crystalline polycarbonate polyol to obtain pre-treated polycarbonate polyol; The pretreated polycarbonate polyol and isocyanate are mixed to carry out polymerization reaction to obtain -NCO terminated polyurethane hot melt adhesive prepolymer; A silane coupling agent, a catalyst and an auxiliary agent are sequentially added to a -NCO-terminated polyurethane hot melt adhesive prepolymer for a modification reaction, and a coatable polyurethane reactive hot melt adhesive is obtained after the modification reaction is completed.

8. The method for preparing a coatable polyurethane reactive hot melt adhesive according to claim 7, characterized in that: The specific steps of the pretreatment are: Add crystalline polycarbonate polyol and non-crystalline polycarbonate polyol into a planetary stirred reactor, heat the planetary stirred reactor to completely melt them into a liquid state, start the vacuum pump, start heating at 100-140°C, maintain the vacuum degree between -0.09MPa and 0.1MPa, and stir at a rate of 50-400r / min, remove water for 1.0-2.5h to obtain pretreated polycarbonate polyol.

9. The method for preparing a coatable polyurethane reactive hot melt adhesive according to claim 7, characterized in that: The process parameters of the polymerization reaction are: the polymerization reaction temperature is 65-95° C., the time is 1.0-3.0 h, the vacuum degree is -0.09 MPa~0.1 MPa, and the stirring rate is 100-300 r / min.

10. The method for preparing a coatable polyurethane reactive hot melt adhesive according to claim 7, characterized in that: The process parameters for the modification reaction of adding silane coupling agent, catalyst and auxiliary agent to -NCO terminated polyurethane hot melt adhesive prepolymer in sequence are as follows: the vacuum degree is maintained between -0.09MPa and 0.1MPa, nitrogen protection, stirring rate is 100-300r / min, the modification reaction temperature when adding silane coupling agent is 65-95°C, and the time is 0.05-1.0h; the promotion reaction temperature when adding catalyst is 65-95°C, and the time is 0.1-1.0h; the supplementary reaction temperature for performance when adding auxiliary agent is 60-90°C, and the time is 0.5-1.0h.

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