Organic-inorganic composite solvent-free polyurethane laminating adhesive and its preparation method and use

Abstract

The present invention provides an organic-inorganic composite solvent-free polyurethane laminating adhesive and its preparation method and use. The laminating adhesive comprises component A and component B. Component A contains surface-modified inorganic nanoparticles and trimethylolpropane tris(3-mercaptopropionic acid). Through microwave-assisted in-situ polymerization, the active groups on the surfaces of the inorganic nanoparticles react with isocyanate groups to obtain an isocyanate-terminated organic-inorganic composite polyurethane prepolymer, which also contains thiourethane groups. Component B comprises surface-modified inorganic nanoparticles, polyether polyol, hydroxyl-terminated dimethylsiloxane, polyester polyol, a hydrolysis-resistant agent, and a coupling agent. The introduction of inorganic nanoparticles and thiourethane groups solves the problems of poor bonding strength and corrosion resistance of existing solvent-free polyurethane laminating adhesives.

Description

Technical Field

[0001] The invention belongs to the field of packaging materials, and particularly relates to an organic-inorganic composite solvent-free polyurethane laminating adhesive and a preparation method and application thereof. Background Art

[0002] Solvent-free polyurethane laminating adhesive is a compound composed of isocyanate and polyol components in a specific ratio. By adjusting the ratio, the film's hardness can be adjusted, making it suitable for plastic-plastic and aluminum-plastic flexible packaging with different structures. Furthermore, because it contains no solvents, it offers advantages such as environmental friendliness, safety, and health benefits. Currently, it is gradually replacing solvent-based polyurethane adhesives on a large scale in the flexible packaging lamination film sector. While solvent-free polyurethane laminating adhesives are increasingly popular for plastic-plastic and aluminum-plastic packaging containing conventional contents, their strong penetrability can easily lead to adhesive delamination when packaging corrosive contents (such as ethyl maltol additives, facial mask liquids, and ketchup). Currently, solvent-based polyurethane adhesives are the primary choice for lamination, and most solvent-free adhesives cannot meet these requirements. Chinese patent CN1081485361B discloses a solvent-based polyurethane laminating adhesive that is resistant to media. By incorporating a special polyol and epoxy resin, the composite aluminum-plastic film can be used to package contents such as acids and alkalis, ethyl maltol additives, and daily cosmetics. However, the patent also points out that most solvent-free polyurethane laminating adhesives cannot meet the requirements for packaging with high media resistance. Chinese patent CN112048278A discloses a two-component, solvent-free, retort-resistant polyurethane laminating adhesive and its preparation method. Component A is prepared by reacting a high-temperature-resistant polyester polyol with a polyisocyanate, while component B consists of a castor oil-modified polyester polyol, a polyether polyol, and an anti-hydrolysis agent. The laminating adhesive's high-temperature retort resistance is enhanced by introducing nanofillers into the polyester polyol. However, this method simply physically mixes the nanofiller with the polyester polyol, which can easily cause turbidity or sedimentation after prolonged storage. Furthermore, the laminating adhesive cannot package corrosive contents.

[0003] In summary, the existing aluminum-plastic structure composited with solvent-free polyurethane laminating adhesive still has the problem of easy delamination after aging when packaging corrosive contents such as ethyl maltol additives, facial mask liquid, tomato sauce, etc. due to the poor corrosion resistance of the glue. Summary of the Invention

[0004] One of the technical problems solved by the present invention is to provide a method for preparing an organic-inorganic composite solvent-free polyurethane laminating adhesive, in which inorganic nanoparticles can be evenly grafted into the network structure of the organic polymer by microwave-assisted in-situ polymerization. Figure 1 As shown, compared with simple physical mixing, this method avoids the problem of uneven dispersion of inorganic nanoparticles in the adhesive and easy agglomeration and sedimentation.

[0005] The second technical problem solved by the present invention is that trimethylolpropane tris (3-mercaptopropionic acid) ester is introduced into the organic-inorganic composite solvent-free polyurethane laminating adhesive to improve the degree of crosslinking of the polymer space network, such as Figure 2 As shown in the figure, the synergistic effect of the inorganic nanoparticles in the molecular chain overcomes the poor corrosion resistance of existing solvent-free polyurethane adhesives. Furthermore, the thiolcarbamate groups further enhance the bonding strength of the solvent-free polyurethane adhesive by hydrogen bonding with reactive groups on the film's surface. Consequently, the composite film formed by combining aluminum foil and polypropylene film with this organic-inorganic composite solvent-free adhesive maintains a peel strength exceeding 3.5N / 15mm even after packaging contents such as alcohol wipes, facial mask liquid, and ketchup.

[0006] The third technical problem solved by the present invention is to optimize the existing synthesis method of solvent-free polyurethane laminating adhesive and provide a method of ultrasonic dispersion + microwave reaction in situ polymerization. This method has two advantages. First, it can greatly shorten the reaction time from 3-5 hours in traditional heating reaction methods to 5-30 minutes, which can greatly improve production efficiency. Second, this method can quickly graft inorganic nanoparticles into the spatial network structure of polyurethane, thereby avoiding agglomeration and sedimentation of inorganic nanoparticles.

[0007] In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

[0008] An organic-inorganic composite solvent-free polyurethane laminating adhesive, comprising an inorganic nanoparticle-modified isocyanate-terminated organic-inorganic composite polyurethane prepolymer component A and an inorganic nanoparticle-modified hydroxyl-terminated organic-inorganic composite polyol component B;

[0009] The raw materials of component A contain trimethylolpropane tris(3-mercaptopropionate), and the raw materials of component B contain terminal hydroxyl diblock polydimethylsiloxane.

[0010] In the present invention, the mass ratio of component A to component B is 100:(50-75), preferably 100:(55-70).

[0011] Organic-inorganic composite solvent-free polyurethane laminating adhesive not only solves the problem of easy sedimentation of inorganic nanoparticles by grafting modified inorganic nanoparticles into the spatial network structure of polyurethane, but also improves the density of the adhesive film. At the same time, the thiocarbamate group can further enhance the hydrogen bonding effect with the surface active groups of the membrane material, thereby improving the bonding strength and corrosion resistance of the laminating adhesive.

[0012] Another object of the present invention is to provide a method for preparing an organic-inorganic composite solvent-free polyurethane laminating adhesive.

[0013] A method for preparing the organic-inorganic composite solvent-free polyurethane laminating adhesive comprises the following steps:

[0014] S1: dispersing inorganic nanoparticles containing active groups on their surfaces in an isocyanate compound to react and generate an inorganic modified isocyanate component A1;

[0015] S2: reacting A1 with polyether polyol and polyester polyol 1, adding trimethylolpropane tris(3-mercaptopropionate) to generate inorganic nanoparticle-modified isocyanate-terminated organic-inorganic composite polyurethane prepolymer component A;

[0016] S3: dispersing inorganic nanoparticles having active groups on their surfaces in an isocyanate compound to react and generate an inorganic modified isocyanate component B1;

[0017] S4: B1 is mixed with polyether polyol, polyester polyol 1, polyester polyol 2, terminal hydroxyl double-terminated polydimethylsiloxane, and additives to react to generate inorganic nanoparticle-modified terminal hydroxyl organic-inorganic composite polyol component B.

[0018] In the present invention, the active groups on the surface of the inorganic nanoparticles containing active groups in S1 are one or more of hydroxyl groups and amino groups, and the inorganic nanoparticles are one or more of silicon dioxide, titanium dioxide, and zirconium dioxide containing active groups on the surface; preferably, the size of the inorganic nanoparticles containing active groups on the surface is 50-1000 nm, preferably 200-600 nm.

[0019] In the present invention, the content of the inorganic nanoparticles containing active groups on the surface in A1 described in S1 is 0.5-10%, based on the total mass of A1.

[0020] In the present invention, the dispersion method in S1 is ultrasonic dispersion, with an ultrasonic power of 50-200W, an ultrasonic time of 5-30min, and a temperature controlled at -5-30°C.

[0021] In the present invention, the reaction in S1 is carried out under microwave heating, with a power setting of 50-300 W, a temperature setting of 60-150° C., and a stirring speed of 50-200 rpm / min.

[0022] In the present invention, the polyether polyol described in S2 has a functionality ≥ 2 and a molecular weight of 400-4000; preferably, the functionality is 2 and the molecular weight is 400-2000.

[0023] In the present invention, the polyester polyol 1 described in S2 has a hydroxyl value of 50-220 mgKOH / g and a viscosity of 1000-5000 mPa﹒ s at 25°C; preferably, the hydroxyl value is 120-200 mgKOH / g and the viscosity is 2000-4000 mPa﹒ s at 25°C.

[0024] In the present invention, the reaction in S2 is carried out under microwave heating with a power setting of 100 W, a temperature setting of 90° C., and a stirring speed of 100 rpm / min.

[0025] In the present invention, the active groups on the surface of the inorganic nanoparticles containing active groups in S3 are one or more of hydroxyl groups and amino groups, and the inorganic nanoparticles are one or more of silicon dioxide, titanium dioxide, and zirconium dioxide containing active groups on the surface; preferably, the size of the inorganic nanoparticles containing active groups on the surface is 50-1000 nm.

[0026] In the present invention, the content of the inorganic nanoparticles containing active groups on the surface in B1 described in S3 is 0.1-5%, based on the total mass of B1.

[0027] In the present invention, the dispersion method in S3 is ultrasonic dispersion, with an ultrasonic power of 50-200W, an ultrasonic time of 5-30min, and a temperature controlled at -5-30°C.

[0028] In the present invention, the reaction in S3 is carried out under microwave heating, with a power setting of 50-300 W, a temperature setting of 60-150° C., and a stirring speed of 50-200 rpm / min.

[0029] In the present invention, the polyether polyol described in S4 has a functionality ≥ 2 and a molecular weight of 400-5000; preferably, the functionality is 2 and 3, and the molecular weight is 700-3000.

[0030] In the present invention, the polyester polyol 1 in S4 has a hydroxyl value of 50-220 mgKOH / g and a viscosity of 1000-5000 mPa﹒ s at 25°C; preferably, the hydroxyl value is 120-200 mgKOH / g and the viscosity is 2000-4000 mPa﹒ s at 25°C.

[0031] In the present invention, the polyester polyol 2 described in S4 has a hydroxyl value of 80-230 mgKOH / g and a viscosity of 10,000-50,000 mPa﹒ s at 70°C; preferably, the hydroxyl value is 130-210 mgKOH / g and the viscosity is 20,000-40,000 mPa﹒ s at 70°C.

[0032] In the present invention, the reaction in S4 is carried out under microwave heating, with a power setting of 50-300 W, a temperature setting of 60-150° C., and a stirring speed of 50-200 rpm / min.

[0033] In the present invention, the auxiliary agent described in S4 is a siloxane coupling agent and a carbodiimide anti-hydrolysis agent, preferably one or more of γ-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, N,N'-bis(2,6-diisopropylphenyl)carbodiimide, N,N'-dicyclohexylcarbodiimide, and N,N'-bis-2,6-dimethylphenylcarbodiimide.

[0034] Another object of the present invention is to provide a use of an organic-inorganic composite solvent-free polyurethane laminating adhesive.

[0035] Disclosed is a use of an organic-inorganic composite solvent-free polyurethane laminating adhesive, wherein the laminating adhesive is the laminating adhesive described above, or is prepared by the above preparation method. The laminating adhesive is used in the field of flexible packaging polyurethane laminating adhesive, and is preferably used for plastic-plastic structures and aluminum-plastic structures in food and daily chemical packaging.

[0036] Compared with the prior art, the present invention has the following positive effects:

[0037] (1) The prepared organic-inorganic composite solvent-free polyurethane laminating adhesive has good corrosion resistance. After packaging ethyl maltol additives, facial mask liquid, tomato sauce and other contents, after aging test at 50℃ / 120h, its peel strength is still higher than 3.5N / 15mm.

[0038] (2) The prepared organic-inorganic composite solvent-free polyurethane laminating adhesive remained clear and transparent after being stored at 50°C for one month, and its performance did not decay. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of the reaction of inorganic nanoparticles grafting polymers;

[0040] Figure 2 Schematic diagram for the introduction of thiocarbamate groups. DETAILED DESCRIPTION

[0041] Device Information:

[0042] Ultrasonic disperser: Model: KQ-300DE; Manufacturer: Kunshan Ultrasonic Instrument Co., Ltd.

[0043] Microwave reactor: Model: XH100B; Manufacturer: Beijing Xianghu Technology Development Co., Ltd.

[0044] Intelligent tensile testing machine: Model: XLW; Manufacturer: Jinan Languang Electromechanical Technology Co., Ltd.

[0045] Solvent-free laminating machine: Model: A-350; Manufacturer: Guangzhou Tongze Machinery Co., Ltd.

[0046] Raw material information:

[0047] MDI-50: NCO: 33.5wt%; Wanhua Chemical Group Co., Ltd.; Brand:

[0048] MDI-100: NCO: 33.5wt%; Wanhua Chemical Group Co., Ltd.; Brand:

[0049] Liquefied MDI: NCO: 30wt%; Wanhua Chemical Group Co., Ltd.; Brand:

[0050] Polyether polyol (molecular weight 400): hydroxyl value (mgKOH / g): 270-290; functionality: 2; Shandong Bluestar Dongda Co., Ltd.; brand: DL-400.

[0051] Polyether polyol (molecular weight 1000): hydroxyl value (mgKOH / g): 109-115; functionality: 2; Shandong Bluestar Dongda Co., Ltd.; brand: DL-1000D.

[0052] Polyether polyol (molecular weight 2000): hydroxyl value (mgKOH / g): 54.5-57.5; functionality: 2; Shandong Bluestar Dongda Co., Ltd.; brand: DL-2000D.

[0053] Polyether polyol (molecular weight 1000): hydroxyl value (mgKOH / g): 165-171; functionality: 3; Shandong Bluestar Dongda Co., Ltd.; brand: MN-1000.

[0054] Hydroxyl-terminated polydimethylsiloxane: molecular weight: 1000; purity: chemical analysis; Shanghai Aladdin Biochemical Technology Co., Ltd.

[0055] N,N'-bis(2,6-diisopropylphenyl)carbodiimide: purity: 98%; Shanghai Aladdin Biochemical Technology Co., Ltd.

[0056] γ-Glycidyloxypropyltrimethoxysilane: Purity: 97%; Shanghai Aladdin Biochemical Technology Co., Ltd.

[0057] γ-Aminopropyltriethoxysilane: Purity: 98%; Shanghai Aladdin Biochemical Technology Co., Ltd.

[0058] Trimethylolpropane tris(3-mercaptopropionate): purity: 85%; Beijing Yinuokai Technology Co., Ltd.

[0059] Nanosilica: particle size: 200 nm; Shanghai Aladdin Biochemical Technology Co., Ltd.

[0060] Nanosilica: particle size: 500 nm; Shanghai Aladdin Biochemical Technology Co., Ltd.

[0061] Nano-titanium dioxide: particle size: 200 nm; Shanghai Aladdin Biochemical Technology Co., Ltd.

[0062] Preparation Example 1

[0063] 2g of nano-silica was added to 50ml of Tris-HCl buffer (pH 7.5-8.5), and the silica was evenly dispersed in the buffer by ultrasonic treatment. 15g of dopamine was then added to the reaction solution and evenly dispersed by ultrasonic treatment. The reaction was stirred at 30°C for 24h, and the reaction solution was filtered, washed, and dried to obtain amino-modified nano-silica C1. The same method was used to obtain amino-modified nano-titanium dioxide C2.

[0064] Example 1

[0065] S1: Add 50g MDI-50 and 10g liquefied MDI to a reaction flask, lower the temperature of the reaction flask to 0°C in an ice bath, add 2g surface-modified nano-titanium dioxide C2 with a particle size of 200nm, place the reaction flask in an ultrasonic disperser, set the ultrasonic power to 200W, and maintain the ultrasonic disperser at 0°C for 10 minutes; transfer the reaction flask to a microwave reactor, set the power to 200W, the temperature to 95°C, and the stirring rate to 100rpm / min; set the reaction time to 10 minutes to obtain the inorganic modified isocyanate component A1.

[0066] S2: Pour 10 g of polyether polyol (DL-400), 13 g of polyether polyol (DL-1000), and 10 g of polyester polyol 1 into reaction flask A1, then transfer the reaction flask to a microwave reactor, set the power to 250 W, the temperature to 95 ° C, the stirring rate to 100 rpm / min; set the reaction time to 10 min; then add 5 g of trimethylolpropane tris (3-mercaptopropionic acid) ester, set the microwave reactor power to 250 W, the temperature to 95 ° C, the stirring rate to 100 rpm / min; set the reaction time to 10 min, and you can get the inorganic nanoparticle-modified terminal isocyanate organic-inorganic composite polyurethane prepolymer component A.

[0067] S3: 8 g of MDI-100 was added to the reaction flask and the temperature of the reaction flask was lowered to 0°C by ice bath. Then, 0.2 g of surface-modified nano-titanium dioxide C2 with a particle size of 200 nm was added. The reaction flask was placed in an ultrasonic disperser with the ultrasonic power set to 200 W. While maintaining the ice bath in the ultrasonic disperser, ultrasonic dispersion treatment was performed for 10 minutes. The reaction flask was then transferred to a microwave reactor with the power set to 250 W, the temperature set to 95°C, and the stirring rate set to 100 rpm / min. The reaction time was set to 10 minutes to obtain the inorganic modified isocyanate component B1.

[0068] S4: Add 15g of polyether polyol (DL-1000), 10g of polyether polyol (DL-2000), 20g of polyether polyol (MN-1000), 10g of polyester polyol 1, 28g of polyester polyol 2, 5g of terminal hydroxyl di-terminated polydimethylsiloxane, and 1g of N,N'-bis(2,6-diisopropylphenyl)carbodiimide to the reaction flask B1, transfer the reaction flask to a microwave reactor, set the power to 250W, the temperature to 95°C, and the stirring rate to 100rpm / min; set the reaction time to 10min, then add 2g of γ-glycidyloxypropyltrimethoxysilane and 1g of γ-aminopropyltriethoxysilane, and stir evenly to obtain the inorganic nanoparticle-modified terminal hydroxyl organic-inorganic composite polyol component B.

[0069] The component A and the component B are uniformly mixed in a mass ratio of 100:68 to obtain an organic-inorganic composite solvent-free polyurethane laminating adhesive.

[0070] Example 2

[0071] S1: Add 50g MDI-50 and 10g liquefied MDI to a reaction flask, lower the temperature of the reaction flask to 25°C, add 2g surface-modified nano-silica C1 with a particle size of 500nm, place the reaction flask in an ultrasonic disperser, set the ultrasonic power to 100W, and maintain the temperature in the ultrasonic disperser at 25°C for 20min of ultrasonic dispersion treatment; transfer the reaction flask to a microwave reactor, set the power to 100W, the temperature to 80°C, and the stirring rate to 200rpm / min; set the reaction time to 20min to obtain the inorganic modified isocyanate component A1.

[0072] S2: Pour 10 g of polyether polyol (DL-400), 13 g of polyether polyol (DL-1000); and 10 g of polyester polyol 1 into reaction flask A1, transfer the reaction flask to a microwave reactor, set the power to 100 W, the temperature to 80° C., and the stirring rate to 200 rpm / min; set the reaction time to 30 min, add 5 g of trimethylolpropane tris(3-mercaptopropionic acid) ester, set the microwave reactor power to 100 W, the temperature to 80° C., and the stirring rate to 200 rpm / min; set the reaction time to 10 min, and the inorganic nanoparticle-modified terminal isocyanate organic-inorganic composite polyurethane prepolymer component A can be obtained.

[0073] S3: Add 8 g of MDI-100 to the reaction flask, lower the temperature of the reaction flask to 25°C, add 0.2 g of surface-modified nano-silica C1 with a particle size of 500 nm, place the reaction flask in an ultrasonic disperser, set the ultrasonic power to 100 W, and maintain the ultrasonic disperser in an ice bath for 20 minutes; transfer the reaction flask to a microwave reactor, set the power to 100 W, the temperature to 80°C, and the stirring rate to 200 rpm / min; set the reaction time to 10 minutes to obtain the inorganic modified isocyanate component B1.

[0074] S4: Add 15g of polyether polyol (DL-1000), 10g of polyether polyol (DL-2000), 20g of polyether polyol (MN-1000), 10g of polyester polyol 1, 28g of polyester polyol 2, 5g of terminal hydroxyl di-terminated polydimethylsiloxane, and 1g of N,N'-bis(2,6-diisopropylphenyl)carbodiimide to the reaction flask B1, transfer the reaction flask to a microwave reactor, set the power to 100W, the temperature to 80°C, and the stirring rate to 200rpm / min; set the reaction time to 30min, then add 2g of γ-glycidyloxypropyltrimethoxysilane and 1g of γ-aminopropyltriethoxysilane, and stir evenly to obtain the inorganic nanoparticle-modified terminal hydroxyl organic-inorganic composite polyol component B.

[0075] The component A and the component B are uniformly mixed in a mass ratio of 100:68 to obtain an organic-inorganic composite solvent-free polyurethane laminating adhesive.

[0076] Example 3

[0077] S1: Add 50g MDI-50 and 10g liquefied MDI to a reaction flask, lower the temperature of the reaction flask to 0°C in an ice bath, add 2g surface-modified nano-titanium dioxide C2 with a particle size of 500nm, place the reaction flask in an ultrasonic disperser, set the ultrasonic power to 200W, and maintain the ultrasonic disperser at 0°C for 10 minutes; transfer the reaction flask to a microwave reactor, set the power to 200W, the temperature to 95°C, and the stirring rate to 100rpm / min; set the reaction time to 10 minutes to obtain the inorganic modified isocyanate component A1.

[0078] S2: Pour 10 g of polyether polyol (DL-400), 13 g of polyether polyol (DL-1000), and 10 g of polyester polyol 1 into reaction flask A1, then transfer the reaction flask to a microwave reactor, set the power to 250 W, the temperature to 95 ° C, the stirring rate to 100 rpm / min; set the reaction time to 10 min; then add 5 g of trimethylolpropane tris (3-mercaptopropionic acid) ester, set the microwave reactor power to 250 W, the temperature to 95 ° C, the stirring rate to 100 rpm / min; set the reaction time to 10 min, and you can get the inorganic nanoparticle-modified terminal isocyanate organic-inorganic composite polyurethane prepolymer component A.

[0079] S3: 8 g of MDI-100 was added to the reaction flask and the temperature of the reaction flask was lowered to 0°C by ice bath. Then, 0.2 g of surface-modified nano-titanium dioxide C2 with a particle size of 200 nm was added. The reaction flask was placed in an ultrasonic disperser with the ultrasonic power set to 200 W. While maintaining the ice bath in the ultrasonic disperser, ultrasonic dispersion treatment was performed for 10 minutes. The reaction flask was then transferred to a microwave reactor with the power set to 250 W, the temperature set to 95°C, and the stirring rate set to 100 rpm / min. The reaction time was set to 10 minutes to obtain the inorganic modified isocyanate component B1.

[0080] S4: Add 15g of polyether polyol (DL-1000), 10g of polyether polyol (DL-2000), 20g of polyether polyol (MN-1000), 10g of polyester polyol 1, 28g of polyester polyol 2, 5g of terminal hydroxyl di-terminated polydimethylsiloxane, and 1g of N,N'-bis(2,6-diisopropylphenyl)carbodiimide to the reaction flask B1, transfer the reaction flask to a microwave reactor, set the power to 250W, the temperature to 95°C, and the stirring rate to 100rpm / min; set the reaction time to 10min, then add 2g of γ-glycidyloxypropyltrimethoxysilane and 1g of γ-aminopropyltriethoxysilane, and stir evenly to obtain the inorganic nanoparticle-modified terminal hydroxyl organic-inorganic composite polyol component B.

[0081] The organic-inorganic composite solvent-free polyurethane laminating adhesive is obtained by uniformly mixing component A and component B in a mass ratio of 100:60.

[0082] Example 4

[0083] S1: Add 50g MDI-50 and 10g liquefied MDI to a reaction flask, lower the temperature of the reaction flask to 0°C in an ice bath, add 1g surface-modified nano-titanium dioxide C2 with a particle size of 200nm, place the reaction flask in an ultrasonic disperser, set the ultrasonic power to 200W, and maintain the ultrasonic disperser at 0°C for 10min; transfer the reaction flask to a microwave reactor, set the power to 200W, the temperature to 95°C, and the stirring rate to 100rpm / min; set the reaction time to 10min to obtain the inorganic modified isocyanate component A1.

[0084] S2: Pour 10 g of polyether polyol (DL-400), 13 g of polyether polyol (DL-1000), and 10 g of polyester polyol 1 into reaction flask A1, then transfer the reaction flask to a microwave reactor, set the power to 250 W, the temperature to 95 ° C, the stirring rate to 100 rpm / min; set the reaction time to 10 min; then add 5 g of trimethylolpropane tris (3-mercaptopropionic acid) ester, set the microwave reactor power to 250 W, the temperature to 95 ° C, the stirring rate to 100 rpm / min; set the reaction time to 10 min, and you can get the inorganic nanoparticle-modified terminal isocyanate organic-inorganic composite polyurethane prepolymer component A.

[0085] S3: 8 g of MDI-100 was added to the reaction flask and the temperature of the reaction flask was lowered to 0°C by ice bath. Then, 0.4 g of surface-modified nano-titanium dioxide C2 with a particle size of 200 nm was added. The reaction flask was placed in an ultrasonic disperser with the ultrasonic power set to 200 W. While maintaining the ice bath in the ultrasonic disperser, ultrasonic dispersion treatment was performed for 10 minutes. The reaction flask was then transferred to a microwave reactor with the power set to 250 W, the temperature set to 95°C, and the stirring rate set to 100 rpm / min. The reaction time was set to 10 minutes to obtain the inorganic modified isocyanate component B1.

[0086] S4: Add 15g of polyether polyol (DL-1000), 10g of polyether polyol (DL-2000), 20g of polyether polyol (MN-1000), 10g of polyester polyol 1, 28g of polyester polyol 2, 5g of terminal hydroxyl di-terminated polydimethylsiloxane, and 1g of N,N'-bis(2,6-diisopropylphenyl)carbodiimide to the reaction flask B1, transfer the reaction flask to a microwave reactor, set the power to 250W, the temperature to 95°C, and the stirring rate to 100rpm / min; set the reaction time to 10min, then add 2g of γ-glycidyloxypropyltrimethoxysilane and 1g of γ-aminopropyltriethoxysilane, and stir evenly to obtain the inorganic nanoparticle-modified terminal hydroxyl organic-inorganic composite polyol component B.

[0087] The component A and the component B are uniformly mixed in a mass ratio of 100:68 to obtain an organic-inorganic composite solvent-free polyurethane laminating adhesive.

[0088] Comparative Example 1

[0089] Compared with Example 1, the difference lies in that no thiourethane and surface-modified nanoparticles are contained.

[0090] S1: Add 50g of MDI-50 and 10g of liquefied MDI into a reaction flask, pour 10g of polyether polyol (DL-400), 13g of polyether polyol (DL-1000), and 10g of polyester polyol 1 into the reaction flask, then transfer the reaction flask to a microwave reactor, set the power to 250W, the temperature to 95°C, the stirring rate to 100rpm / min, and the reaction time to 10min to obtain the isocyanate-terminated polyurethane prepolymer component A.

[0091] S2: Add 8g of MDI-100 to the reaction flask, and add 15g of polyether polyol (DL-1000), 10g of polyether polyol (DL-2000), 20g of polyether polyol (MN-1000), 10g of polyester polyol 1, 28g of polyester polyol 2, 5g of end-hydroxyl di-terminated polydimethylsiloxane and 1g of N,N'-bis(2,6-diisopropylphenyl)carbodiimide to the flask, and then transfer the reaction flask to a microwave reactor, set the power to 250W, the temperature to 95°C, and the stirring rate to 100rpm / min; set the reaction time to 10min, and then add 2g of γ-glycidyloxypropyltrimethoxysilane and 1g of γ-aminopropyltriethoxysilane, stir evenly to obtain polyol B component.

[0092] The solvent-free polyurethane laminating adhesive is obtained by uniformly mixing component A and component B in a mass ratio of 100:68.

[0093] Comparative Example 2

[0094] Compared with Example 1, the difference is that the surface-modified nanoparticles are not contained.

[0095] S1: Add 50g of MDI-50 and 10g of liquefied MDI to a reaction flask, pour 10g of polyether polyol (DL-400), 13g of polyether polyol (DL-1000), and 10g of polyester polyol 1 into the reaction flask, then transfer the reaction flask to a microwave reactor, set the power to 250W, the temperature to 95°C, the stirring rate to 100rpm / min, and the reaction time to 10min; then add 5g of trimethylolpropane tris(3-mercaptopropionic acid) ester, set the microwave reactor power to 250W, the temperature to 95°C, the stirring rate to 100rpm / min, and the reaction time to 10min, to obtain the terminal isocyanate polyurethane prepolymer component A.

[0096] S2: Add 8g of MDI-100 to the reaction flask, and add 15g of polyether polyol (DL-1000), 10g of polyether polyol (DL-2000), 20g of polyether polyol (MN-1000), 10g of polyester polyol 1, 28g of polyester polyol 2, 5g of end-hydroxyl di-terminated polydimethylsiloxane and 1g of N,N'-bis(2,6-diisopropylphenyl)carbodiimide to the flask, and then transfer the reaction flask to a microwave reactor, set the power to 250W, the temperature to 95°C, and the stirring rate to 100rpm / min; set the reaction time to 10min, and then add 2g of γ-glycidyloxypropyltrimethoxysilane and 1g of γ-aminopropyltriethoxysilane, stir evenly to obtain polyol B component.

[0097] The solvent-free polyurethane laminating adhesive is obtained by uniformly mixing component A and component B in a mass ratio of 100:68.

[0098] Comparative Example 3

[0099] Compared with Example 1, the difference is that thiocarbamate is not contained.

[0100] S1: Add 50g MDI-50 and 10g liquefied MDI to a reaction flask, lower the temperature of the reaction flask to 0°C in an ice bath, add 2g surface-modified nano-titanium dioxide C2 with a particle size of 200nm, place the reaction flask in an ultrasonic disperser, set the ultrasonic power to 200W, and maintain the ice bath in the ultrasonic disperser for ultrasonic dispersion treatment for 10min; transfer the reaction flask to a microwave reactor, set the power to 250W, the temperature to 95°C, and the stirring rate to 100rpm / min; set the reaction time to 10min to obtain the inorganic modified isocyanate component A1.

[0101] S2: Pour 10 g of polyether polyol (DL-400), 13 g of polyether polyol (DL-1000), and 10 g of polyester polyol 1 into the reaction flask A1, then transfer the reaction flask to a microwave reactor, set the power to 250 W, the temperature to 95 ° C, the stirring rate to 100 rpm / min; set the reaction time to 10 min; and obtain the inorganic nanoparticle-modified terminal isocyanate organic-inorganic composite polyurethane prepolymer component A.

[0102] S3: 8 g of MDI-100 was added to the reaction flask and the temperature of the reaction flask was lowered to 0°C by ice bath. Then, 0.2 g of surface-modified nano-titanium dioxide C2 with a particle size of 200 nm was added. The reaction flask was placed in an ultrasonic disperser with the ultrasonic power set to 200 W. While maintaining the ice bath in the ultrasonic disperser, ultrasonic dispersion treatment was performed for 10 minutes. The reaction flask was then transferred to a microwave reactor with the power set to 250 W, the temperature set to 95°C, and the stirring rate set to 100 rpm / min. The reaction time was set to 10 minutes to obtain the inorganic modified isocyanate component B1.

[0103] S4: Add 15g of polyether polyol (DL-1000), 10g of polyether polyol (DL-2000), 20g of polyether polyol (MN-1000), 10g of polyester polyol 1, 28g of polyester polyol 2, 5g of terminal hydroxyl di-terminated polydimethylsiloxane, and 1g of N,N'-bis(2,6-diisopropylphenyl)carbodiimide to the reaction flask B1, transfer the reaction flask to a microwave reactor, set the power to 250W, the temperature to 95°C, and the stirring rate to 100rpm / min; set the reaction time to 10min, then add 2g of γ-glycidyloxypropyltrimethoxysilane and 1g of γ-aminopropyltriethoxysilane, and stir evenly to obtain the inorganic nanoparticle-modified terminal hydroxyl organic-inorganic composite polyol component B.

[0104] The component A and the component B are uniformly mixed in a mass ratio of 100:68 to obtain an organic-inorganic composite solvent-free polyurethane laminating adhesive.

[0105] Comparative Example 4

[0106] Compared with Example 1, the difference is that ordinary nanoparticles (not surface modified) are used.

[0107] S1: Add 50g MDI-50 and 10g liquefied MDI to a reaction flask and lower the temperature of the reaction flask to 0°C in an ice bath. Add 2g of ordinary nano-titanium dioxide with a particle size of 200nm. Place the reaction flask in an ultrasonic disperser with the ultrasonic power set to 200W. While maintaining the ice bath in the ultrasonic disperser, ultrasonic dispersion treatment is carried out for 10 minutes. Transfer the reaction flask to a microwave reactor with the power set to 250W, the temperature set to 95°C, and the stirring rate set to 100rpm / min. The reaction time is set to 10 minutes to obtain the inorganic modified isocyanate component A1.

[0108] S2: Pour 10 g of polyether polyol (DL-400), 13 g of polyether polyol (DL-1000), and 10 g of polyester polyol 1 into reaction flask A1, then transfer the reaction flask to a microwave reactor, set the power to 250 W, the temperature to 95 ° C, the stirring rate to 100 rpm / min; set the reaction time to 10 min; then add 5 g of trimethylolpropane tris (3-mercaptopropionic acid) ester, set the microwave reactor power to 250 W, the temperature to 95 ° C, the stirring rate to 100 rpm / min; set the reaction time to 10 min, and you can get the inorganic nanoparticle-modified terminal isocyanate organic-inorganic composite polyurethane prepolymer component A.

[0109] S3: 8 g of MDI-100 was added to the reaction flask and the temperature of the reaction flask was lowered to 0°C by ice bath. Then, 0.2 g of ordinary nano-titanium dioxide with a particle size of 200 nm was added. The reaction flask was placed in an ultrasonic disperser with the ultrasonic power set to 200 W. While maintaining the ice bath in the ultrasonic disperser, ultrasonic dispersion treatment was performed for 10 minutes. The reaction flask was then transferred to a microwave reactor with the power set to 250 W, the temperature set to 95°C, and the stirring rate set to 100 rpm / min. The reaction time was set to 10 minutes to obtain the inorganic modified isocyanate component B1.

[0110] S4: Add 15g of polyether polyol (DL-1000), 10g of polyether polyol (DL-2000), 20g of polyether polyol (MN-1000), 10g of polyester polyol 1, 28g of polyester polyol 2, 5g of terminal hydroxyl di-terminated polydimethylsiloxane, and 1g of N,N'-bis(2,6-diisopropylphenyl)carbodiimide to the reaction flask B1, transfer the reaction flask to a microwave reactor, set the power to 250W, the temperature to 95°C, and the stirring rate to 100rpm / min; set the reaction time to 10min, then add 2g of γ-glycidyloxypropyltrimethoxysilane and 1g of γ-aminopropyltriethoxysilane, and stir evenly to obtain the inorganic nanoparticle-modified terminal hydroxyl organic-inorganic composite polyol component B.

[0111] The component A and the component B are uniformly mixed in a mass ratio of 100:68 to obtain an organic-inorganic composite solvent-free polyurethane laminating adhesive.

[0112] Comparative Example 5

[0113] Compared with Example 1, the difference is that ultrasonic dispersion and microwave-assisted in-situ polymerization are not used.

[0114] S1: Add 50g MDI-50 and 10g liquefied MDI to a reaction flask, add 2g surface-modified nano-titanium dioxide C2 with a particle size of 200nm, heat the reaction flask to 95°C in an oil bath, and set the stirring rate to 100rpm / min; react for 60min to obtain the inorganic modified isocyanate component A1.

[0115] S2: Pour 10g of polyether polyol (DL-400), 13g of polyether polyol (DL-1000), and 10g of polyester polyol 1 into reaction flask A1, then heat the reaction flask to 95°C in an oil bath, set the stirring rate to 100rpm / min; react for 180min; then add 5g of trimethylolpropane tris(3-mercaptopropionic acid) ester, at 95°C, the stirring rate is 100rpm / min; continue the reaction for 60min to obtain the inorganic nanoparticle-modified terminal isocyanate organic-inorganic composite polyurethane prepolymer component A.

[0116] S3: Add 8 g of MDI-100 to the reaction flask, followed by 0.2 g of surface-modified nano-titanium dioxide C2 with a particle size of 200 nm. Heat the reaction flask to 95°C in an oil bath with a stirring rate of 100 rpm / min. React for 60 min to obtain the inorganic modified isocyanate component B1.

[0117] S4: Add 15g of polyether polyol (DL-1000), 10g of polyether polyol (DL-2000), 20g of polyether polyol (MN-1000), 10g of polyester polyol 1, 28g of polyester polyol 2, 5g of end-hydroxyl di-terminated polydimethylsiloxane, and 1g of N,N'-bis(2,6-diisopropylphenyl)carbodiimide to the reaction flask B1, heat the reaction flask to 95°C in an oil bath, and set the stirring rate to 100rpm / min; react for 120min, then add 2g of γ-glycidyloxypropyltrimethoxysilane and 1g of γ-aminopropyltriethoxysilane, and stir evenly to obtain the inorganic nanoparticle-modified end-hydroxyl organic-inorganic composite polyol component B.

[0118] The component A and the component B are uniformly mixed in a mass ratio of 100:68 to obtain an organic-inorganic composite solvent-free polyurethane laminating adhesive.

[0119] The adhesives obtained in Examples 1-4 to Comparative Examples 1-5 were used to compound PET / AL / PP layers, and then the performance tests were performed. As shown in Table 1 below, the PET / AL / PP layers were compounded using a Tongze A-350 solventless compounder, and the glue amount was set to 1.8 g / m 2 The composite film material was aged at 45°C for 72 hours, and then a peel strength test was performed; the film material was cut into composite films of 150mm*150mm size, and then made into bags, which were filled with facial mask liquid, tomato sauce and 0.5% ethyl maltol aqueous solution respectively. The bags were placed at 50°C and aged for 120 hours before testing; a peel strength test was performed using an intelligent tensile testing machine (model: XLW), and the peel strength test method was carried out in accordance with GB 8808-88.

[0120] Table 1

[0121]

[0122]

[0123] By comparing Example 1 with Comparative Example 1, it can be found that by grafting surface-modified inorganic nanoparticles into the spatial network structure of solvent-free polyurethane, the density of the polyurethane spatial network structure can be improved, thereby significantly improving the corrosion resistance of the polyurethane adhesive.

[0124] The organic-inorganic composite solvent-free polyurethane adhesives obtained from Examples 1-4 to Comparative Examples 1-5 were placed at 50° C. for one month and then subjected to performance tests. In addition, the presence of agglomeration and sedimentation was observed (√ indicates no agglomeration and turbidity; ○ indicates slight agglomeration and turbidity; × indicates agglomeration and turbidity), as shown in Table 2:

[0125] Table 2

[0126]

[0127] A comparison of Example 1 and Comparative Example 4 in Table 2 reveals that the organic-inorganic composite solvent-free polyurethane adhesive obtained by simple physical blending exhibited significant agglomeration and sedimentation after one month of storage, and its corrosion resistance also significantly decreased. A comparison of Example 1 and Comparative Example 5 reveals that microwave-assisted in-situ polymerization enables more uniform grafting of inorganic nanoparticles into the organic polymer network, resulting in better performance than samples obtained using conventional oil bath heating and stirring.

[0128] The above description is only a preferred embodiment of the present invention. The protection scope of the present invention is not limited to the above embodiment. For ordinary technicians in this technical field, any simple replacement or deduction without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. An organic-inorganic composite solvent-free polyurethane laminating adhesive, characterized in that: The laminating adhesive comprises an inorganic nanoparticle-modified isocyanate-terminated organic-inorganic composite polyurethane prepolymer component A and an inorganic nanoparticle-modified hydroxyl-terminated organic-inorganic composite polyol component B; The raw materials of component A contain trimethylolpropane tris(3-mercaptopropionate), and the raw materials of component B contain hydroxyl-terminated di-capped polydimethylsiloxane. The preparation method of the components A and B comprises the following steps: S1: dispersing inorganic nanoparticles containing active groups on their surfaces in an isocyanate compound to react and generate an inorganic modified isocyanate component A1; S2: reacting A1 with polyether polyol and polyester polyol 1, adding trimethylolpropane tris(3-mercaptopropionate) to generate inorganic nanoparticle-modified isocyanate-terminated organic-inorganic composite polyurethane prepolymer component A; S3: dispersing inorganic nanoparticles having active groups on their surfaces in an isocyanate compound to react and generate an inorganic modified isocyanate component B1; S4: mixing B1 with polyether polyol, polyester polyol 1, polyester polyol 2, hydroxyl-terminated di-blocked polydimethylsiloxane, and additives to react to form inorganic nanoparticle-modified hydroxyl-terminated organic-inorganic composite polyol component B; Wherein, the dispersion method of S1 and S3 is ultrasonic dispersion; the reaction of S1-S4 is carried out under microwave heating.

2. The laminating adhesive according to claim 1, characterized in that The mass ratio of component A to component B is 100:(50-75).

3. The laminating adhesive according to claim 2, characterized in that The mass ratio of component A to component B is 100:(55-70).

4. A method for preparing the organic-inorganic composite solvent-free polyurethane laminating adhesive according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: S1: dispersing inorganic nanoparticles containing active groups on their surfaces in an isocyanate compound to react and generate an inorganic modified isocyanate component A1; S2: reacting A1 with polyether polyol and polyester polyol 1, adding trimethylolpropane tris(3-mercaptopropionate) to generate inorganic nanoparticle-modified isocyanate-terminated organic-inorganic composite polyurethane prepolymer component A; S3: dispersing inorganic nanoparticles having active groups on their surfaces in an isocyanate compound to react and generate an inorganic modified isocyanate component B1; S4: B1 is mixed with polyether polyol, polyester polyol 1, polyester polyol 2, terminal hydroxyl double-terminated polydimethylsiloxane, and additives to react to generate inorganic nanoparticle-modified terminal hydroxyl organic-inorganic composite polyol component B.

5. The preparation method according to claim 4, characterized in that The active groups on the surface of the inorganic nanoparticles containing active groups in S1 are one or more of hydroxyl groups and amino groups, and the inorganic nanoparticles are one or more of silicon dioxide, titanium dioxide, and zirconium dioxide containing active groups on the surface; and / or, the content of inorganic nanoparticles containing active groups on the surface of A1 in S1 is 0.5-10%, based on the total mass of A1; And / or, the dispersion method in S1 is ultrasonic dispersion, with an ultrasonic power of 50-200 W, an ultrasonic time of 5-30 min, and a temperature controlled at -5-30°C; And / or, the reaction in S1 is carried out under microwave heating with a power setting of 50-300 W, a temperature setting of 60-150° C., and a stirring speed of 50-200 rpm / min.

6. The preparation method according to claim 5, characterized in that The size of the inorganic nanoparticles containing active groups on the surface in S1 is 50-1000 nm.

7. The preparation method according to claim 6, characterized in that The size of the inorganic nanoparticles containing active groups on the surface in S1 is 200-600 nm.

8. The preparation method according to claim 4, characterized in that The polyether polyol S2 has a functionality of ≥2 and a molecular weight of 400-4000; And / or, the polyester polyol 1 in S2 has a hydroxyl value of 50-220 mgKOH / g and a viscosity of 1000-5000 mPa﹒s at 25°C; And / or, the reaction in S2 is carried out under microwave heating with a power setting of 100 W, a temperature setting of 90° C., and a stirring speed of 100 rpm / min.

9. The preparation method according to claim 8, characterized in that The polyether polyol described in S2 has a functionality of 2 and a molecular weight of 400-2000; And / or, the polyester polyol 1 in S2 has a hydroxyl value of 120-200 mgKOH / g and a viscosity of 2000-4000 mPa﹒s at 25°C.

10. The preparation method according to claim 4, characterized in that The surface active groups of the inorganic nanoparticles containing active groups in S3 are one or more of hydroxyl groups and amino groups, and the inorganic nanoparticles are one or more of silicon dioxide, titanium dioxide, and zirconium dioxide containing active groups on the surface; and / or, the content of inorganic nanoparticles containing active groups on the surface of B1 in S3 is 0.1-5%, based on the total mass of B1; And / or, the dispersion method in S3 is ultrasonic dispersion, with an ultrasonic power of 50-200 W, an ultrasonic time of 5-30 min, and a temperature controlled at -5-30° C.; And / or, the reaction in S3 is carried out under microwave heating, with a power setting of 50-300 W, a temperature setting of 60-150° C., and a stirring speed of 50-200 rpm / min.

11. The preparation method according to claim 10, characterized in that: The size of the inorganic nanoparticles containing active groups on the surface of S3 is 50-1000 nm.

12. The preparation method according to claim 11, characterized in that The size of the inorganic nanoparticles containing active groups on the surface of S3 is 200-600 nm.

13. The preparation method according to claim 4, characterized in that The polyether polyol described in S4 has a functionality of ≥2 and a molecular weight of 400-5000; And / or, the polyester polyol 1 in S4 has a hydroxyl value of 50-220 mgKOH / g and a viscosity of 1000-5000 mPa﹒s at 25°C; And / or, the polyester polyol in S4 has a hydroxyl value of 80-230 mgKOH / g and a viscosity of 10,000-50,000 mPa﹒s at 70°C; And / or, the reaction in S4 is carried out under microwave heating with a power setting of 50-300 W, a temperature setting of 60-150° C., and a stirring speed of 50-200 rpm / min; And / or, the auxiliary agent in S4 is a siloxane coupling agent and a carbodiimide anti-hydrolysis agent.

14. The preparation method according to claim 13, characterized in that The polyether polyol described in S4 has a functionality of 2 and 3 and a molecular weight of 700-3000; And / or, the polyester polyol 1 in S4 has a hydroxyl value of 120-200 mgKOH / g and a viscosity of 2000-4000 mPa﹒s at 25°C; and / or, the polyester polyol in S4 has a hydroxyl value of 130-210 mgKOH / g and a viscosity of 20,000-40,000 mPa﹒s at 70°C; And / or, the auxiliary agent in S4 is one or more of γ-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, N,N'-bis(2,6-diisopropylphenyl)carbodiimide, N,N'-dicyclohexylcarbodiimide, and N,N'-bis-2,6-dimethylphenylcarbodiimide.

15. Use of an organic-inorganic composite solvent-free polyurethane laminating adhesive, wherein the laminating adhesive is the laminating adhesive described in any one of claims 1 to 3, or the laminating adhesive prepared by the preparation method described in any one of claims 4 to 14, and the laminating adhesive is used in the field of flexible packaging polyurethane laminating adhesive.

16. The use according to claim 15, characterized in that The laminating adhesive is used for plastic-plastic structures and aluminum-plastic structures in food and daily chemical packaging.

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