Composite adhesive for stone and preparation method thereof

Abstract

The invention relates to the technical field of adhesives, in particular to a composite adhesive for stone and a preparation method of the composite adhesive. The composite adhesive for stone consists of a component A and a component B, and is characterized in that the component A consists of the following raw materials in parts by weight: 50-75 parts of epoxy resin, 7-13 parts of polyester polyol, 3-7 parts of a diluent, 3-7 parts of a dispersing agent and 12-30 parts of a modified filler; the modified filler is organic silicon glycidyl ether modified white carbon black; and the component B is prepared from the following raw materials in parts by weight: 15-30 parts of a curing agent, 4-10 parts of ethylene glycol, 1-4 parts of a coupling agent and 0.5-2 parts of an antioxidant. The prepared composite adhesive has low viscosity in a molten state, the adhesive can more uniformly permeate into fine gaps of stone, meanwhile, the mechanical property is good, and the defects of uneven thickness, damage, cracks and the like of the stone are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and particularly relates to a composite adhesive for stone and a preparation method thereof. Background Art

[0002] As a natural building material, stone, due to its unique texture, high strength and durability, endows buildings with a more contemporary and artistic sense in its unique style, and is widely used in fields such as architectural decoration, interior and exterior decoration, and sculpture art, becoming one of the important symbols for urban buildings to enter the modern era. However, during the processing, installation and use of stone, adhesives are often required for splicing, repairing or fixing. Although traditional stone adhesives have a certain bonding strength, the following problems still exist in practical applications: limited bonding strength, poor water resistance, and long surface drying time. Epoxy stone composite adhesives are a type of load-bearing structural adhesives that meet national standards, with advantages such as a wide bonding range, simple processing, high strength and good chemical resistance, and their application is closely related to the on-site construction environment.

[0003] However, existing composite adhesives still have some limitations in practical applications, such as complex preparation processes, high costs, low viscosity, and insufficient stability. Therefore, developing a stone composite adhesive with high bonding strength and mechanical properties has become an important research direction in the current stone processing and application fields.

[0004] The purpose of the present invention is to provide a composite adhesive for stone, which, by optimizing the formulation design and preparation process, solves the disadvantages of traditional adhesives such as high viscosity in the molten state, difficulty in entering the stone, resulting in easy cracking, breakage and insufficient mechanical properties of the stone during use, and meets the bonding requirements of stone in different usage environments. Summary of the Invention

[0005] In view of the above deficiencies in the prior art, the present invention provides a composite adhesive for stone and a preparation method thereof.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A composite adhesive for stone is composed of component A and component B. Component A is composed of the following raw materials in parts by weight: 50 - 75 parts by weight of epoxy resin, 7 - 13 parts by weight of polyester polyol, 3 - 7 parts by weight of diluent, 3 - 7 parts by weight of dispersant, 12 - 30 parts by weight of modified filler; the modified filler is modified silica.

[0008] Component B is composed of the following raw materials in parts by weight: 15 - 30 parts by weight of curing agent, 4 - 10 parts by weight of ethylene glycol, 1 - 4 parts by weight of coupling agent, 0.5 - 2 parts by weight of antioxidant.

[0009] The diluent is any one of cardanol non-active epoxy diluent, methyl silicone oil, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, and ethyl acetate.

[0010] The dispersant is any one of sodium dodecylbenzenesulfonate, octylphenol polyoxyethylene ether, and fatty acid monoethanolamide.

[0011] The curing agent is any one of 3-methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and methylnadic anhydride.

[0012] The coupling agent is any one of γ-chloropropylmethyldialkoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane.

[0013] The antioxidant is any one of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid.

[0014] Most of the existing adhesives for stone plate composite are prone to delamination and have high viscosity. Due to their high viscosity, when applying the adhesive on the stone surface, it is not conducive to penetrate into the fine gaps of the stone, which may lead to difficulties in brushing operation, uneven thickness, breakage, cracks and other defects in the ultra-thin stone after peeling. And during the process of heating, curing and cooling into a cured product, epoxy resin as an adhesive will shrink and generate internal stress, which is easy to produce cracks inside the cured product, making the epoxy resin not impact-resistant and having poor toughness, resulting in poor toughness and low impact strength of the existing epoxy resin adhesives.

[0015] As a nano-level filler, silica white is often used as a filler in adhesives because of its non-toxic, odorless and environmentally friendly properties, and it can significantly improve the strength, hardness and wear resistance of the adhesive. However, silica white has poor dispersibility and is easy to agglomerate in the epoxy resin matrix; the interfacial compatibility between the epoxy resin matrix and silica white is poor, and the mechanical properties of the rubber compound are poor. When using silica white to prepare adhesives, it must be modified.

[0016] The specific reaction mechanism is as follows: S1 uses fumed silica as the main raw material. The fumed silica particles are well-dispersed by ultrasound to increase its specific surface area, making the active sites on its surface more likely to react with silanes. Under the conditions of heating and stirring, carboxylated fumed silica is obtained; S2 uses 4-hydroxybutyl acrylate glycidyl ether and silane coupling agent as the main reaction raw materials, dimethyl sulfoxide as the reaction solvent, and chloroplatinic acid-isopropanol as the catalyst. The siloxane groups (-Si(OR)3) of the silane coupling agent hydrolyze in the solvent to form silanols (-Si(OH)3). Subsequently, the silanols undergo a condensation reaction to form siloxane-silicon bonds (-Si-O-Si-), generating an organosilicon polymer with a network structure. The epoxy groups (glycidyl groups) of the glycidyl ether have high reactivity and can undergo a ring-opening reaction with the hydroxyl or amino groups in the organosilicon polymer under the conditions of heating and stirring to form chemical bonds, obtaining organosilicon glycidyl ether; S3 uses carboxylated fumed silica and organosilicon glycidyl ether as the main raw materials. Under heating conditions, the carboxyl groups in the carboxylated fumed silica and the hydroxyl or amino groups in the organosilicon glycidyl ether undergo an esterification or amide reaction to form a graft, and finally, organosilicon glycidyl ether-modified fumed silica is obtained.

[0017] The preparation method of the modified fumed silica is as follows:

[0018] S1. Disperse 8 - 14 parts by weight of fumed silica in 80 - 160 parts by weight of N,N-dimethylformamide, place it under ultrasonic conditions with an ultrasonic power of 100 - 300 W and an ultrasonic frequency of 40 - 70 kHz for 0.5 - 2 h, add 1 - 4 parts by weight of N-[β-(N,N-diacetyl)aminoethyl]-γ-(N-acetyl)aminopropyltrimethoxysilane, and react at 50 - 70 °C and 400 - 800 rpm for 2 - 6 h. Then, centrifuge, wash, and dry to obtain carboxylated fumed silica;

[0019] S2. Mix 4 - 8 parts by weight of 4-hydroxybutyl acrylate glycidyl ether, 0.5 - 2 parts by weight of silane coupling agent, and 40 - 90 parts by weight of dimethyl sulfoxide, add 0.05 - 0.2 parts by weight of chloroplatinic acid-isopropanol, and react at 90 - 110 °C and 300 - 500 rpm for 2 - 6 h to obtain organosilicon glycidyl ether;

[0020] S3. Disperse 5 - 10 parts by weight of the above-mentioned carboxylated fumed silica in 80 - 160 parts by weight of N,N-dimethylformamide, place it under ultrasonic conditions with an ultrasonic power of 100 - 300 W and an ultrasonic frequency of 40 - 70 kHz for 0.5 - 2 h, add 2 - 5 parts by weight of organosilicon glycidyl ether, and react at 50 - 70 °C and 400 - 800 rpm for 4 - 8 h. Then, filter, wash, and dry to obtain modified fumed silica.

[0021] The modified silica prepared by the present invention has the following advantages when applied to the composite adhesive for stone: By modifying silica with organosilicon glycidyl ether, the organosilicon group provides steric hindrance, reducing the entanglement between epoxy resin segments, keeping the epoxy resin at a lower viscosity, which is beneficial to the uniform mixing of the modified silica with other components in the adhesive. When the two are mixed and cured, an interpenetrating network structure is formed, effectively compensating for the disadvantages of large brittleness and poor toughness after the curing of epoxy resin, and thus improving the mechanical properties of the stone. Due to functional groups such as carboxyl and epoxy groups on the surface of the modified silica, it can chemically react with the hydroxyl groups on the stone surface to form strong chemical bonds. This chemical bonding significantly improves the adhesion between the adhesive and the stone, thereby enhancing the overall strength and toughness of the adhesive, and effectively preventing the peeling between the adhesive and the stone caused by external forces. The nanostructure of the modified silica can be evenly dispersed in the adhesive and uniformly dispersed in the resin matrix, forming a uniform reinforcing phase, which can effectively disperse stress. When the matrix is impacted, there is a strong affinity between the silica and the matrix, reducing the formation of defects after curing, being able to effectively transfer stress, increasing the cohesive force, absorbing impact energy, and preventing the adhesive layer from breaking under a large instantaneous impact force, playing a good toughening role. At the same time, it can also improve the shear strength and fluidity of the adhesive, while reducing the shrinkage of the adhesive during the curing process, thereby preventing the cracking of the adhesive caused by shrinkage and increasing the service life.

[0022] The silane coupling agent in S2 is at least one of N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane and diethylenetriaminepropyltrimethoxysilane; preferably, the silane coupling agent is a mixture composed of N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane and diethylenetriaminepropyltrimethoxysilane in a mass ratio of (2-4):1.

[0023] The present invention preferably selects the silane coupling agent as a mixture composed of N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane and diethylenetriaminepropyltrimethoxysilane in a mass ratio of (2-4):1. The reason is that N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane contains hydroxyl and amino groups, which can react with the epoxy groups of glycidyl ether to form chemical bonds. However, its reaction activity may be limited by the number of amino groups and secondary amines. And diethylenetriaminepropyltrimethoxysilane contains multiple amino groups, which can provide more reaction sites and better dispersion performance. The combined action of multiple amino groups can provide more reaction sites and higher reaction activity. This synergistic effect can significantly enhance the chemical bonding between glycidyl ether and organosilicon polymer, improve the performance of the modified silica, and ultimately improve the comprehensive performance of the adhesive.

[0024] The preparation method of the composite adhesive for stone includes the following steps:

[0025] (1) Weigh each raw material by weight parts;

[0026] (2) Heat the epoxy resin to 50 - 70 °C, add the polyester polyol and the diluent, mix evenly, then add the dispersant and the modified filler, and stir at 4000 - 10000 rpm for 20 - 50 min to obtain Component A;

[0027] (3) Mix the curing agent, ethylene glycol, coupling agent, and antioxidant evenly, and stir at 800 - 1500 rpm for 20 - 50 min to obtain Component B;

[0028] (4) Adjust the glue by mixing Component A and Component B according to the weight ratio of (1.5 - 2.5):1, and after mixing evenly, obtain the composite adhesive for stone.

[0029] The beneficial effects of the present invention: The present invention provides a composite adhesive for stone and its preparation method. Through the optimization of raw materials and reasonable raw material ratios, the prepared composite adhesive has a lower viscosity in the molten state, which can make the adhesive penetrate more evenly into the fine gaps of the stone. At the same time, it has better mechanical properties, avoiding defects such as uneven thickness, breakage, and cracks in the stone.

[0030] For the adhesive for stone plate composite provided by the present invention, adding modified silica in the raw materials is beneficial to the uniform mixing of the modified silica with other components in the adhesive, which can improve the bonding force between the adhesive and the stone, thereby improving the overall strength and toughness of the adhesive. At the same time, it can also improve the shear strength and fluidity of the adhesive, and reduce the shrinkage of the adhesive during the curing process, thereby preventing the cracking of the adhesive caused by shrinkage and improving the service life.

[0031] The adhesive for stone plate composite provided by the present invention has the advantages of no delamination, good brushing performance, convenient use, low shrinkage rate, etc. It is an epoxy resin adhesive with excellent performance, and the cured stone composite plate meets the production requirements, has high processing efficiency, and lower production costs. Specific embodiments

[0032] The following further describes in detail the above-mentioned inventive content of the present invention in combination with specific embodiments, but this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments.

[0033] Introduction of some raw materials in this application:

[0034] The epoxy resin is purchased from Wuhan Chenfengxin Trading Co., Ltd., with the brand E - 51.

[0035] The polyester polyol was purchased from Tianjin Ruike Chemical Trading Co., Ltd., with the model RD-9618.

[0036] Example 1

[0037] A composite adhesive for stone is composed of component A and component B: Component A is composed of the following raw materials by weight: 60 parts by weight of epoxy resin, 10 parts by weight of polyester polyol, 5 parts by weight of diluent, 5 parts by weight of dispersant, and 20 parts by weight of filler;

[0038] Component B is composed of the following raw materials by weight: 20 parts by weight of curing agent, 6 parts by weight of ethylene glycol, 2 parts by weight of coupling agent, and 1 part by weight of antioxidant.

[0039] The diluent is trimethylolpropane triglycidyl ether.

[0040] The dispersant is sodium dodecylbenzenesulfonate.

[0041] The curing agent is 3-methyltetrahydrophthalic anhydride.

[0042] The coupling agent is γ-methacryloxypropyltrimethoxysilane.

[0043] The antioxidant is pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0044] The filler is silica white.

[0045] The preparation method of the composite adhesive for stone includes the following steps:

[0046] (1) Weigh each raw material according to the parts by weight;

[0047] (2) Heat the epoxy resin to 60 °C, add the polyester polyol and diluent, mix evenly, then add the dispersant and filler, and stir at 8000 rpm for 30 min to obtain component A;

[0048] (3) Mix the curing agent, ethylene glycol, coupling agent, and antioxidant evenly, and stir at 1200 rpm for 30 min to obtain component B;

[0049] (4) Adjust the glue of component A and component B according to the weight ratio of 2:1, and after mixing evenly, obtain the composite adhesive for stone.

[0050] Example 2

[0051] A composite adhesive for stone is composed of component A and component B: Component A is composed of the following raw materials by weight: 60 parts by weight of epoxy resin, 10 parts by weight of polyester polyol, 5 parts by weight of diluent, 5 parts by weight of dispersant, and 20 parts by weight of modified filler;

[0052] The component B is composed of the following raw materials by weight: 20 parts by weight of curing agent, 6 parts by weight of ethylene glycol, 2 parts by weight of coupling agent, and 1 part by weight of antioxidant.

[0053] The diluent is trimethylolpropane triglycidyl ether.

[0054] The dispersant is sodium dodecylbenzenesulfonate.

[0055] The curing agent is 3-methyltetrahydrophthalic anhydride.

[0056] The coupling agent is γ-methacryloxypropyltrimethoxysilane.

[0057] The antioxidant is pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0058] The modified filler is modified silica white, and the preparation method of the modified silica white is as follows: Disperse 10 parts by weight of silica white in 100 parts by weight of N,N-dimethylformamide, place it under the conditions of ultrasonic power of 200 W and ultrasonic frequency of 60 kHz for ultrasonic treatment for 1 h, add 3 parts by weight and then add 1-4 parts by weight of N-[β-(N,N-diacetyl)aminoethyl]-γ-(N-acetyl)aminopropyltrimethoxysilane, place it at 60 °C and 600 rpm for reaction for 4 h, centrifuge, wash, and dry to obtain carboxylated silica white.

[0059] The preparation method of the composite adhesive for stone includes the following steps:

[0060] (1) Weigh each raw material according to the parts by weight;

[0061] (2) Heat the epoxy resin to 60 °C, add the polyester polyol and the diluent, mix evenly, then add the dispersant and the modified filler, and stir at 8000 rpm for 30 min to obtain component A;

[0062] (3) Mix the curing agent, ethylene glycol, coupling agent, and antioxidant evenly, and stir at 1200 rpm for 30 min to obtain component B;

[0063] (4) Adjust the glue of component A and component B according to the weight ratio of 2:1, and after mixing evenly, obtain the composite adhesive for stone.

[0064] Example 3

[0065] A composite adhesive for stone is composed of component A and component B: The component A is composed of the following raw materials by weight: 60 parts by weight of epoxy resin, 10 parts by weight of polyester polyol, 5 parts by weight of diluent, 5 parts by weight of dispersant, and 20 parts by weight of modified filler;

[0066] The B component consists of the following raw materials in parts by weight: 20 parts by weight of a curing agent, 6 parts by weight of ethylene glycol, 2 parts by weight of a coupling agent, and 1 part by weight of an antioxidant.

[0067] The diluent is trimethylolpropane triglycidyl ether.

[0068] The dispersant is sodium dodecylbenzenesulfonate.

[0069] The curing agent is 3-methyltetrahydrophthalic anhydride.

[0070] The coupling agent is γ-methacryloxypropyltrimethoxysilane.

[0071] The antioxidant is pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0072] The modified filler is modified silica, and the preparation method of the modified silica is as follows:

[0073] S1. Mix 6 parts by weight of 4-hydroxybutyl acrylate glycidyl ether, 1 part by weight of a silane coupling agent, and 50 parts by weight of dimethyl sulfoxide, add 0.1 part by weight of chloroplatinic acid-isopropanol, and react at 100 °C and 400 rpm for 4 h to obtain an organosilicon glycidyl ether; the silane coupling agent is a mixture of N-(3-acryloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane and diethylenetriaminepropyltrimethoxysilane in a mass ratio of 3:1;

[0074] S2. Disperse 8 parts by weight of silica in 100 parts by weight of N,N-dimethylformamide, place it under ultrasonic conditions with an ultrasonic power of 200 W and an ultrasonic frequency of 60 kHz for 1 h, add 3 parts by weight of the organosilicon glycidyl ether, react at 60 °C and 600 rpm for 6 h, filter, wash, and dry to obtain the modified silica.

[0075] The preparation method of the composite adhesive for stone includes the following steps:

[0076] (1) Weigh each raw material according to parts by weight;

[0077] (2) Heat the epoxy resin to 60 °C, add the polyester polyol and the diluent, mix evenly, then add the dispersant and the modified filler, and stir at 8000 rpm for 30 min to obtain the A component;

[0078] (3) Mix the curing agent, ethylene glycol, coupling agent, and antioxidant evenly, and stir at 1200 rpm for 30 min to obtain the B component;

[0079] (4) Adjust the glue of the A component and the B component according to a weight ratio of 2:1, and mix evenly to obtain the composite adhesive for stone.

[0080] Example 4

[0081] A composite adhesive for stone, which is composed of component A and component B: Component A is composed of the following raw materials in parts by weight: 60 parts by weight of epoxy resin, 10 parts by weight of polyester polyol, 5 parts by weight of diluent, 5 parts by weight of dispersant, 20 parts by weight of modified filler;

[0082] Component B is composed of the following raw materials in parts by weight: 20 parts by weight of curing agent, 6 parts by weight of ethylene glycol, 2 parts by weight of coupling agent, 1 part by weight of antioxidant.

[0083] The diluent is trimethylolpropane triglycidyl ether.

[0084] The dispersant is sodium dodecylbenzenesulfonate.

[0085] The curing agent is 3-methyltetrahydrophthalic anhydride.

[0086] The coupling agent is γ-methacryloxypropyltrimethoxysilane.

[0087] The antioxidant is pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0088] The modified filler is modified silica, and the preparation method of the modified silica is as follows:

[0089] S1. Disperse 10 parts by weight of silica in 100 parts by weight of N,N-dimethylformamide, place it under ultrasonic conditions with an ultrasonic power of 200 W and an ultrasonic frequency of 60 kHz for 1 h, add 3 parts by weight, add 1-4 parts by weight of N-[β-(N,N-diacetyl)aminoethyl]-γ-(N-acetyl)aminopropyltrimethoxysilane, place it at 60 °C and 600 rpm for reaction for 4 h, centrifuge, wash, and dry to obtain carboxylated silica;

[0090] S2. Mix 6 parts by weight of 4-hydroxybutyl acrylate glycidyl ether, 1 part by weight of silane coupling agent and 50 parts by weight of dimethyl sulfoxide, add 0.1 part by weight of chloroplatinic acid-isopropanol, and react at 100 °C and 400 rpm for 4 h to obtain organosilicon glycidyl ether; the silane coupling agent is N-(3-acryloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane;

[0091] S3. Disperse 8 parts by weight of the above carboxylated silica in 100 parts by weight of N,N-dimethylformamide, place it under ultrasonic conditions with an ultrasonic power of 200 W and an ultrasonic frequency of 60 kHz for 1 h, add 3 parts by weight of organosilicon glycidyl ether, and react at 60 °C and 600 rpm for 6 h, filter by suction, wash, and dry to obtain modified silica.

[0092] The preparation method of the composite adhesive for stone includes the following steps:

[0093] (1) Weigh each raw material according to parts by weight;

[0094] (2) Heat the epoxy resin to 60 °C, add the polyester polyol and the diluent, mix evenly, then add the dispersant and the modified filler, and stir at 8000 rpm for 30 min to obtain Component A;

[0095] (3) Mix the curing agent, ethylene glycol, coupling agent, and antioxidant evenly, and stir at 1200 rpm for 30 min to obtain Component B;

[0096] (4) Adjust the glue of Component A and Component B according to the weight ratio of 2:1, and after mixing evenly, obtain the composite adhesive for stone.

[0097] Example 5

[0098] A composite adhesive for stone, which is composed of Component A and Component B: Component A is composed of the following raw materials in parts by weight: 60 parts by weight of epoxy resin, 10 parts by weight of polyester polyol, 5 parts by weight of diluent, 5 parts by weight of dispersant, and 20 parts by weight of modified filler;

[0099] Component B is composed of the following raw materials in parts by weight: 20 parts by weight of curing agent, 6 parts by weight of ethylene glycol, 2 parts by weight of coupling agent, and 1 part by weight of antioxidant.

[0100] The diluent is trimethylolpropane triglycidyl ether.

[0101] The dispersant is sodium dodecylbenzenesulfonate.

[0102] The curing agent is 3-methyltetrahydrophthalic anhydride.

[0103] The coupling agent is γ-methacryloyloxypropyltrimethoxysilane.

[0104] The antioxidant is pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0105] The modified filler is modified silica white, and the preparation method of the modified silica white is as follows:

[0106] S1. Disperse 10 parts by weight of silica white in 100 parts by weight of N,N-dimethylformamide, place it under ultrasonic power of 200 W and ultrasonic frequency of 60 kHz for ultrasonic treatment for 1 h, add 3 parts by weight and add 1-4 parts by weight of N-[β-(N,N-diacetyl)aminoethyl]-γ-(N-acetyl)aminopropyltrimethoxysilane, place it at 60 °C and 600 rpm for reaction for 4 h, centrifuge, wash, and dry to obtain carboxylated silica white;

[0107] S2. Mix 6 parts by weight of 4-hydroxybutyl acrylate glycidyl ether, 1 part by weight of silane coupling agent and 50 parts by weight of dimethyl sulfoxide, add 0.1 part by weight of chloroplatinic acid-isopropanol, and react at 100 °C and 400 rpm for 4 h to obtain organosilicon glycidyl ether; the silane coupling agent is diethylenetriaminepropyltrimethoxysilane;

[0108] S3. Disperse 8 parts by weight of the carboxylated silica in 100 parts by weight of N,N-dimethylformamide, place it under ultrasonic conditions with an ultrasonic power of 200 W and an ultrasonic frequency of 60 kHz for 1 h, add 3 parts by weight of organosilicon glycidyl ether, react at 60 °C and 600 rpm for 6 h, filter by suction, wash, and dry to obtain modified silica.

[0109] The preparation method of the composite adhesive for stone includes the following steps:

[0110] (1) Weigh each raw material by parts by weight;

[0111] (2) Heat the epoxy resin to 60 °C, add the polyester polyol and the diluent, mix evenly, then add the dispersant and the modified filler, and stir at 8000 rpm for 30 min to obtain component A;

[0112] (3) Mix the curing agent, ethylene glycol, coupling agent, and antioxidant evenly, and stir at 1200 rpm for 30 min to obtain component B;

[0113] (4) Adjust the glue of component A and component B according to a weight ratio of 2:1, and mix evenly to obtain the composite adhesive for stone.

[0114] Example 6

[0115] A composite adhesive for stone is composed of component A and component B: Component A is composed of the following raw materials by parts by weight: 60 parts by weight of epoxy resin, 10 parts by weight of polyester polyol, 5 parts by weight of diluent, 5 parts by weight of dispersant, 20 parts by weight of modified filler;

[0116] Component B is composed of the following raw materials by parts by weight: 20 parts by weight of curing agent, 6 parts by weight of ethylene glycol, 2 parts by weight of coupling agent, 1 part by weight of antioxidant.

[0117] The diluent is trimethylolpropane triglycidyl ether.

[0118] The dispersant is sodium dodecylbenzenesulfonate.

[0119] The curing agent is 3-methyltetrahydrophthalic anhydride.

[0120] The coupling agent is γ-methacryloxypropyltrimethoxysilane.

[0121] The antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0122] The modified filler is modified silica white, and the preparation method of the modified silica white is as follows:

[0123] S1. Disperse 10 parts by weight of silica white in 100 parts by weight of N,N-dimethylformamide, place it under the conditions of ultrasonic power of 200 W and ultrasonic frequency of 60 kHz for ultrasonic treatment for 1 h, add 3 parts by weight of N-[β-(N,N-diacetyl)aminoethyl]-γ-(N-acetyl)aminopropyltrimethoxysilane, place it at 60°C and 600 rpm for reaction for 4 h, centrifuge, wash, and dry to obtain carboxylated silica white;

[0124] S2. Mix 6 parts by weight of 4-hydroxybutyl acrylate glycidyl ether, 1 part by weight of silane coupling agent and 50 parts by weight of dimethyl sulfoxide, add 0.1 part by weight of chloroplatinic acid-isopropanol, and react at 100°C and 400 rpm for 4 h to obtain organosilicon glycidyl ether; the silane coupling agent is a mixture composed of N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane and diethylenetriaminepropyltrimethoxysilane in a mass ratio of 3:1;

[0125] S3. Disperse 8 parts by weight of the above carboxylated silica white in 100 parts by weight of N,N-dimethylformamide, place it under the conditions of ultrasonic power of 200 W and ultrasonic frequency of 60 kHz for ultrasonic treatment for 1 h, add 3 parts by weight of organosilicon glycidyl ether, and react at 60°C and 600 rpm for 6 h, filter, wash, and dry to obtain modified silica white.

[0126] The preparation method of the composite adhesive for stone includes the following steps:

[0127] (1) Weigh each raw material according to parts by weight;

[0128] (2) Heat the epoxy resin to 60°C, add the polyester polyol and the diluent, mix evenly, then add the dispersant and the modified filler, and stir at 8000 rpm for 30 min to obtain component A;

[0129] (3) Mix the curing agent, ethylene glycol, coupling agent and antioxidant evenly, and stir at 1200 rpm for 30 min to obtain component B;

[0130] (4) Adjust the glue of component A and component B according to a weight ratio of 2:1, mix evenly, and obtain the composite adhesive for stone.

[0131] Test Example 1

[0132] Melt viscosity: Measured by an NDJ-5S digital display rotational viscometer at a measurement temperature of 120 °C. The specific steps are as follows: Place the composite adhesive for stone obtained in the example in an electric heating mantle at 120 °C, immerse the rotor in the adhesive, and at the same time place a thermometer in it for measurement. When the thermometer reaches 120 °C, start the rotor, and record the data when the reading is stable. Each group is tested 4 times, and the average value is taken. The test results are shown in Table 1.

[0133] Table 1 Test results of melt viscosity performance

[0134]

[0135]

[0136] Test Example 2

[0137] Peel strength: Refer to the national standard GB / T 2791-1995 "Test Method for T-Peel Strength of Adhesives - Flexible Material to Flexible Material". Use a dispensing machine to evenly apply the composite adhesive for stone obtained in the example on the stone surface and bond them. After curing at room temperature for 24 h, conduct the test. The loading speed is 100 mm / min. Each group of experiments is tested 5 times, and the average value is taken. The test results are shown in Table 2.

[0138] Tensile shear strength: Refer to the test standard JC 887-2001 "Epoxy Adhesive for Dry-Hanging Stone Curtain Wall" to conduct the tensile shear strength test on the composite adhesive for stone obtained in the example. Each group is tested 5 times, and the average value is taken. The test results are shown in Table 2.

[0139] Table 2 Test results of mechanical properties

[0140] Peeling strength (MPa) Tensile-shear strength (stainless steel - stainless steel MPa) Example 1 9.7 7.1 Example 2 11.3 8.5 Example 3 12.9 9.9 Example 4 14.9 11.6 Example 5 14.3 11.2 Example 6 15.8 12.6

[0141] From the above results, it can be seen that the composite adhesive for stone prepared by the present invention has a low melt viscosity, which can make the adhesive penetrate more evenly into the fine gaps of the stone. At the same time, the mechanical properties are relatively good, avoiding defects such as uneven thickness, breakage, and cracks in the stone.

[0142] Specifically comparing Examples 1-4, it can be seen that after using modified silica, the mechanical properties are better than those without modification. The reason is that the silica is modified by organosilicon glycidyl ether. The organosilicon group provides steric hindrance, reducing the entanglement between epoxy resin segments, keeping the epoxy resin at a lower viscosity, which is beneficial to the uniform mixing of the modified silica with other components in the adhesive. The two are mixed and cured to form an interpenetrating network structure, effectively compensating for the disadvantages of high brittleness and poor toughness after the epoxy resin is cured, and thus improving the mechanical properties of the stone. Due to the functional groups such as carboxyl and epoxy groups on the surface of the modified silica, it can chemically react with the hydroxyl groups on the stone surface to form strong chemical bonds. This chemical bonding significantly improves the adhesion between the adhesive and the stone, thereby improving the overall strength and toughness of the adhesive, and can effectively prevent the peeling between the adhesive and the stone caused by external forces. The modified silica nanostructure can be evenly dispersed in the adhesive and evenly dispersed in the resin matrix to form a uniform reinforcing phase, which can effectively disperse stress. When the matrix is impacted, there is a strong affinity between the silica and the matrix, reducing the formation of defects after curing, being able to effectively transfer stress, increasing the cohesive force, absorbing impact energy, and preventing the adhesive layer from breaking under a large instantaneous impact force, playing a good toughening role. At the same time, it can also improve the shear strength and fluidity of the adhesive, while reducing the shrinkage of the adhesive during the curing process, thereby preventing the adhesive from cracking due to shrinkage and increasing the service life.

[0143] Further comparing Examples 4-6, it can be seen that a mixture composed of N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane and diethylenetriaminepropyltrimethoxysilane in a mass ratio of (2-4):1 is used as the silane coupling agent. The reason is that N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane contains hydroxyl and amino groups, which can react with the epoxy groups of glycidyl ether to form chemical bonds. However, its reaction activity may be limited by the number of amino groups and secondary amines. And diethylenetriaminepropyltrimethoxysilane contains multiple amino groups, which can provide more reaction sites and better dispersion performance. The combined action of multiple amino groups can provide more reaction sites and higher reaction activity. This synergistic effect can significantly enhance the chemical bonding between glycidyl ether and organosilicon polymer, improve the performance of the modified silica, and ultimately improve the comprehensive performance of the adhesive.

Claims

1. A composite adhesive for stone, consisting of component A and component B, characterized in that: The component A is composed of the following raw materials in parts by weight: 50-75 parts by weight of epoxy resin, 7-13 parts by weight of polyester polyol, 3-7 parts by weight of diluent, 3-7 parts by weight of dispersant, and 12-30 parts by weight of modified filler; the modified filler is organic silicon glycidyl ether modified white carbon black; The component B is composed of the following raw materials in parts by weight: 15-30 parts by weight of a curing agent, 4-10 parts by weight of ethylene glycol, 1-4 parts by weight of a coupling agent, and 0.5-2 parts by weight of an antioxidant.

2. The composite adhesive for stone according to claim 1, characterized in that: The diluent is any one of cardanol inactive epoxy diluent, methyl silicone oil, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, and ethyl acetate.

3. The composite adhesive for stone according to claim 1, characterized in that: The dispersant is any one of sodium dodecylbenzene sulfonate, octylphenol polyoxyethylene ether, and fatty acid monoethanolamide.

4. The composite adhesive for stone according to claim 1, characterized in that: The curing agent is any one of 3-methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride and methylnadic anhydride.

5. The composite adhesive for stone according to claim 1, characterized in that: The coupling agent is any one of γ-chloropropylmethyldialkoxysilane, γ-glycidyloxypropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane.

6. The composite adhesive for stone according to claim 1, characterized in that: The antioxidant is any one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanuric acid.

7. The composite adhesive for stone according to claim 1, characterized in that: The preparation method of the modified white carbon black is as follows: S1. Disperse 8-14 parts by weight of white carbon black in 80-160 parts by weight of N,N-dimethylformamide, subject the mixture to ultrasonic treatment at an ultrasonic power of 100-300 W and an ultrasonic frequency of 40-70 kHz for 0.5-2 h, add 1-4 parts by weight of N-[β-(N,N-diacetoxy)aminoethyl]-γ-(N-acetoxy)aminopropyltrimethoxysilane, react the mixture at 50-70° C. and 400-800 rpm for 2-6 h, centrifuge, wash, and dry to obtain carboxylated white carbon black; S2, 4-8 parts by weight of 4-hydroxybutyl acrylate glycidyl ether, 0.5-2 parts by weight of silane coupling agent and 40-90 parts by weight of dimethyl sulfoxide are mixed, 0.05-0.2 parts by weight of chloroplatinic acid-isopropanol are added, and the mixture is reacted at 90-110° C. and 300-500 rpm for 2-6 hours to obtain silicone glycidyl ether; S3. Disperse 5-10 parts by weight of the above carboxylated silica in 80-160 parts by weight of N,N-dimethylformamide, ultrasonicate for 0.5-2h at an ultrasonic power of 100-300W and an ultrasonic frequency of 40-70kHz, add 2-5 parts by weight of silicone glycidyl ether, react at 50-70°C and 400-800rpm for 4-8h, filter, wash and dry to obtain modified silica.

8. The composite adhesive for stone according to claim 7, characterized in that: The silane coupling agent in S2 is at least one of N-(3-acryloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane and diethylenetriaminopropyltrimethoxysilane.

9. The method for preparing the composite adhesive for stone according to any one of claims 1 to 8, characterized in that: The steps include: (1) Weigh each raw material by weight; (2) heating the epoxy resin to 50-70° C., adding polyester polyol and diluent, mixing evenly, then adding dispersant and modified filler, stirring at 4000-10000 rpm for 20-50 min, to obtain component A; (3) Mix the curing agent, ethylene glycol, coupling agent and antioxidant evenly, and stir at 800-1500 rpm for 20-50 min to obtain component B; (4) Component A and component B are mixed according to a weight ratio and uniformly prepared to obtain a composite adhesive for stone.

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