Flexible polyurethane synthetic adhesive and preparation method thereof

Abstract

The invention relates to the technical field of synthetic adhesives, and particularly discloses a flexible polyurethane synthetic adhesive and a preparation method thereof. The flexible polyurethane synthetic adhesive disclosed by the invention is prepared from the following raw materials in parts by weight: 15 to 20 parts of functional filler, 40 to 44 parts of polyurethane prepolymer, 0.5 to 0.8 part of de-foaming agent, 1 to 1.5 parts of sodium dodecyl benzene sulfonate, 30 to 35 parts of de-ionized water, 8 to 12 parts of hydroxyethyl acrylate, 0.3 to 0.6 part of dibutyltin dilaurate and 2 to 4 parts of photoinitiator. The flexible polyurethane synthetic adhesive prepared by the invention adopts a unique raw material formula and process, has good flexibility and stability, can be rapidly cured under illumination, is not easy to break, store and age when being attached to surfaces with different shapes, and can also improve the production efficiency, and the used renewable resource palm oil reduces the dependence on petroleum resources, so that the environment-friendly flexible polyurethane synthetic adhesive is suitable for industrial production. The adhesive has the advantages of environmental protection and cost, and is suitable for various scenes such as medical wound dressing and medical instrument bonding.

Description

Technical Field

[0001] The invention relates to the technical field of synthetic adhesives, and in particular discloses a flexible polyurethane synthetic adhesive and a preparation method thereof. Background Art

[0002] As an important polymer material, polyurethane synthetic adhesive has been widely used in many fields due to its excellent mechanical properties, biocompatibility and adjustability, especially in the medical field. It can make the wound dressing fit the skin tightly, prevent the invasion of external pollutants, absorb exudate and promote wound healing; at the same time, it can firmly bond different parts of medical devices to ensure the structural integrity and performance safety of the device. Its good biocompatibility also reduces irritation to the human body, making polyurethane synthetic adhesive one of the important materials in the medical field.

[0003] However, with the development of medical technology and the improvement of performance requirements for medical devices, the existing flexible polyurethane synthetic adhesives have exposed many problems in practical applications, which seriously restricts their further application in the medical field. The production of traditional flexible polyurethane synthetic adhesives relies on a large amount of petroleum resources, resulting in high costs, and over-reliance on petrochemical resources leads to problems such as resource shortages and environmental pollution. The human skin morphology is complex and changeable. Traditional flexible polyurethane synthetic adhesives are difficult to fit closely to the skin surface and are prone to breakage and warping. This not only affects the fixation effect of wound dressings and increases the risk of wound infection, but also causes the bonding parts of medical devices to break easily when the device is subjected to external force during bonding, affecting the service life and safety of the device. However, some flexible polyurethane synthetic adhesives are chemically unstable during storage and are prone to chemical changes, resulting in viscosity fluctuations, affecting the application and bonding effects. After long-term storage, the bonding strength is greatly reduced, which is difficult to meet actual needs. In addition, under the influence of environmental factors such as light, temperature, and humidity, its aging resistance is poor, the performance decays quickly, and the product service life is short. At the same time, the curing process of many current flexible polyurethane synthetic adhesives is relatively slow, and it takes a long time to reach the ideal bonding strength, which greatly increases the production cycle and cost, and seriously limits the improvement of production efficiency, especially in the large-scale production of medical devices and wound dressings, which becomes a bottleneck hindering the expansion of production scale. Therefore, the present invention provides a flexible polyurethane synthetic adhesive and a preparation method thereof to solve the above-mentioned technical problems. Summary of the invention

[0004] The purpose of the present invention is to provide a flexible polyurethane synthetic adhesive and a preparation method thereof. The prepared flexible polyurethane synthetic adhesive has good flexibility and stability, can be quickly cured under light, is not easy to break when bonded to surfaces of different shapes, and is resistant to storage and aging. The renewable resource palm oil used reduces dependence on petroleum resources, has both environmental protection and cost advantages, and is suitable for various scenarios such as medical wound dressings and medical device bonding.

[0005] The present invention provides a flexible polyurethane synthetic adhesive, which adopts the following technical solution:

[0006] A flexible polyurethane synthetic adhesive is composed of the following raw materials in parts by weight: 15-20 parts of functional filler, 40-44 parts of polyurethane prepolymer, 0.5-0.8 parts of defoamer, 1-1.5 parts of sodium dodecylbenzene sulfonate, 30-35 parts of deionized water, 8-12 parts of hydroxyethyl acrylate, 0.3-0.6 parts of dibutyltin dilaurate and 2-4 parts of photoinitiator.

[0007] Preferably, the preparation steps of the flexible polyurethane synthetic adhesive are:

[0008] S1. Preparation of functional fillers:

[0009] S11, dispersing graphene oxide in N,N-dimethylformamide, adding p-toluenesulfonyl chloride and 4-dimethylaminopyridine after ultrasonic treatment for 30-60 minutes, introducing nitrogen protection, stirring continuously at 40-50° C. for 5-7 hours, centrifugally washing and drying to obtain active graphene oxide;

[0010] S12, dissolving polytetramethylene ether glycol in N,N-dimethylformamide, adding active graphene oxide dispersion and potassium carbonate, introducing nitrogen protection, stirring continuously at 80-100° C. for 4-6 hours, and then centrifugally washing and drying to obtain a functional filler;

[0011] S2. Preparation of polyurethane prepolymer:

[0012] S21, adding palm oil and tetrabutylammonium bromide into a reaction kettle, heating to 60-70° C. under stirring, adding peracetic acid dropwise, maintaining the temperature constant and stirring for 4-6 hours to obtain epoxy palm oil;

[0013] S22, adding tetrabutylammonium bromide and L-ascorbic acid to epoxy palm oil, introducing carbon dioxide gas, stirring continuously at 2-3 MPa and 80-90° C. for 6-8 hours to obtain carbonated epoxy palm oil, adding an amine crosslinking agent and 1,8-diazabicyclo[5.4.0]undec-7-ene, stirring continuously at 140-150° C. for 24-28 hours to obtain a polyurethane prepolymer;

[0014] S3, preparing flexible polyurethane synthetic adhesive:

[0015] Functional filler, polyurethane prepolymer, defoamer and sodium dodecylbenzene sulfonate are dispersed in deionized water, stirred at room temperature for 40-60 minutes to obtain an emulsion, hydroxyethyl acrylate and dibutyltin dilaurate are added, stirring is continued at 60-70°C for 2-3 hours, and then a photoinitiator is added, and flexible polyurethane synthetic adhesive is obtained after stirring evenly.

[0016] Preferably, in step S11, the mass ratio of graphene oxide, N,N-dimethylformamide, p-toluenesulfonyl chloride and 4-dimethylaminopyridine is 1-3:35-40:5-8:0.3-0.5.

[0017] Preferably, in step S12, the mass ratio of polytetramethylene ether glycol, N,N-dimethylformamide, activated graphene oxide dispersion and potassium carbonate is 3-5:35-40:1-2:0.3-0.45.

[0018] Preferably, in step S21, the components by weight include 80-100 parts of palm oil, 1-3 parts of tetrabutylammonium bromide and 25-30 parts of peracetic acid.

[0019] Preferably, in step S22, the amine cross-linking agent is composed of isophorone diamine and 4,4'-diaminodiphenyl disulfide in a molar ratio of 1-3:1.

[0020] Preferably, the step S22 comprises 80-100 parts by weight of epoxy palm oil, 1-2 parts by weight of tetrabutylammonium bromide, 0.4-0.6 parts by weight of L-ascorbic acid, 20-25 parts by weight of an amine crosslinking agent and 0.6-0.8 parts by weight of 1,8-diazabicyclo[5.4.0]undec-7-ene.

[0021] Preferably, the defoaming agent in step S3 is at least one of polydimethylsiloxane, polyoxypropylene glycerol ether and polysorbate.

[0022] Preferably, the photoinitiator in step S3 is at least one of benzoin dimethyl ether, 2-hydroxy-2-methyl-1-phenyl-1-propanone and 1-hydroxycyclohexyl phenyl ketone.

[0023] In summary, the present invention has the following beneficial effects:

[0024] 1. The present invention disperses functional fillers, polyurethane prepolymers and other additives in deionized water to form an emulsion, and then adds hydroxyethyl acrylate and photoinitiator to obtain a flexible polyurethane synthetic adhesive. The functional filler gives the synthetic adhesive flexibility, good cohesion and toughness, and excellent aging resistance, ensuring the stable performance of the synthetic adhesive under different environments. The polyurethane prepolymer achieves environmental protection and cost advantages by virtue of renewable raw materials, and reacts with an amino cross-linking agent after epoxy carbonation to improve the comprehensive performance of the material. Hydroxyethyl acrylate can participate in the reaction in the subsequent curing process, further improve the cross-linking degree of the synthetic adhesive, and enhance the mechanical properties and bonding properties of the material. The photoinitiator can generate free radicals under light conditions to initiate the curing reaction of the synthetic adhesive, so that the synthetic adhesive can be quickly cured under light, shortening the curing time and improving production efficiency.

[0025] 2. The functional filler of the present invention is prepared by chemically modifying graphene oxide with polytetramethylene ether glycol after sulfonylation. Polytetramethylene ether glycol, as a flexible soft segment, combines with graphene oxide through chemical bonds to promote uniform dispersion of the filler in the synthetic rubber and enhance the stability of the system. Its flexible chain segment gives the synthetic rubber overall flexibility, and the synergistically formed lamellar network structure enhances the cohesion and toughness of the material, making it adaptable to surfaces of different shapes. In addition, the functional filler can inhibit aging reactions such as hydrolysis and oxidation in high temperature and high humidity environments, maintain the stability of the physical and chemical properties of the synthetic rubber, and significantly improve aging resistance.

[0026] 3. The present invention epoxidizes palm oil and then carbonates it under the action of tetrabutylammonium bromide and L-ascorbic acid, and then reacts it with isophorone diamine and 4,4'-diaminodiphenyl disulfide to obtain a polyurethane prepolymer. Using palm oil as the main raw material reduces dependence on non-renewable resources, reduces production costs and environmental impacts. Through epoxidation and carbonation treatment, epoxy groups and carbonate groups are introduced into the palm oil molecular chain, and these groups can better participate in the subsequent cross-linking reaction and improve the flexibility and mechanical properties of the material. The carbonate group and the cross-linking structure can effectively resist the influence of environmental factors such as light, temperature and humidity, delay the aging process of the material, and extend the service life. L-ascorbic acid can prevent the free radicals generated when carbon dioxide gas reacts with epoxidized palm oil under high temperature and high pressure from inducing side reactions, and maintain the stability of the reaction system. The amine cross-linking agent composed of isophorone diamine and 4,4'-diaminodiphenyl disulfide improves the performance of the final synthetic rubber by enhancing the cross-linking density, improving heat resistance and chemical resistance, and adjusting flexibility. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used are purchased from conventional biochemical reagent stores unless otherwise specified. The quantitative tests in the following examples were repeated three times, and the data are the average or average ± standard deviation of the three repeated experiments.

[0029] Example 1

[0030] A method for preparing a flexible polyurethane synthetic adhesive comprises the following preparation steps:

[0031] S1. Preparation of functional fillers:

[0032] S11, dispersing graphene oxide in N,N-dimethylformamide, ultrasonically treating at 40kHz for 60min, adding p-toluenesulfonyl chloride and 4-dimethylaminopyridine, introducing nitrogen protection, controlling the stirring rate to 200rpm, stirring at 40°C for 7h, centrifuging, washing and drying to obtain active graphene oxide, wherein the mass ratio of graphene oxide, N,N-dimethylformamide, p-toluenesulfonyl chloride and 4-dimethylaminopyridine is 1:35:5:0.3;

[0033] S12, dissolving polytetramethylene ether glycol in N,N-dimethylformamide, adding 8% by mass of active graphene oxide dispersion and potassium carbonate, introducing nitrogen protection, controlling the stirring rate to 200 rpm, stirring continuously for 6 hours at 80° C., centrifugally washing and drying to obtain a functional filler, wherein the mass ratio of polytetramethylene ether glycol, N,N-dimethylformamide, active graphene oxide dispersion and potassium carbonate is 3:35:1:0.3;

[0034] S2. Preparation of polyurethane prepolymer:

[0035] S21, by weight, add 80 parts of palm oil and 1 part of tetrabutylammonium bromide into a reactor, control the stirring rate to 250 rpm, heat to 60° C. under stirring, add 25 parts of peracetic acid dropwise at a rate of 1 ml / min, keep the temperature unchanged, and stir for 6 to obtain epoxy palm oil;

[0036] S22. To 80 parts of epoxy palm oil, add 1 part of tetrabutylammonium bromide and 0.4 part of L-ascorbic acid, by weight, introduce carbon dioxide gas, control the stirring rate to 250 rpm, stir at 2 MPa and 80° C. for 8 h to obtain carbonated epoxy palm oil, add 20 parts of an amine cross-linking agent and 0.6 parts of 1,8-diazabicyclo[5.4.0]undec-7-ene, and continue stirring at 140° C. for 28 h to obtain a polyurethane prepolymer, wherein the amine cross-linking agent is composed of isophorone diamine and 4,4'-diaminodiphenyl disulfide in a molar ratio of 1:1;

[0037] S3, preparing flexible polyurethane synthetic adhesive:

[0038] Functional filler, polyurethane prepolymer, polysorbate and sodium dodecylbenzene sulfonate are dispersed in deionized water, the stirring rate is controlled to be 150 rpm, and the emulsion is obtained after stirring at room temperature for 60 minutes. Hydroxyethyl acrylate and dibutyltin dilaurate are added, and stirring is continued for 3 hours at 60°C. Then 1-hydroxycyclohexyl phenyl ketone is added and stirred evenly to obtain a flexible polyurethane synthetic adhesive.

[0039] Example 2

[0040] A method for preparing a flexible polyurethane synthetic adhesive comprises the following preparation steps:

[0041] S1. Preparation of functional fillers:

[0042] S11, dispersing graphene oxide in N,N-dimethylformamide, ultrasonically treating at 50kHz for 50min, adding p-toluenesulfonyl chloride and 4-dimethylaminopyridine, introducing nitrogen protection, controlling the stirring rate to 250rpm, stirring at 45°C for 6h, centrifuging, washing and drying to obtain active graphene oxide, wherein the mass ratio of graphene oxide, N,N-dimethylformamide, p-toluenesulfonyl chloride and 4-dimethylaminopyridine is 2:36:6:0.5;

[0043] S12, dissolving polytetramethylene ether glycol in N,N-dimethylformamide, adding 10% by mass of active graphene oxide dispersion and potassium carbonate, introducing nitrogen protection, controlling the stirring rate to 250 rpm, stirring continuously for 5 hours at 90° C., centrifugally washing and drying to obtain a functional filler, wherein the mass ratio of polytetramethylene ether glycol, N,N-dimethylformamide, active graphene oxide dispersion and potassium carbonate is 4:38:2:0.38;

[0044] S2. Preparation of polyurethane prepolymer:

[0045] S21, by weight, add 90 parts of palm oil and 2 parts of tetrabutylammonium bromide into a reactor, control the stirring rate to 260 rpm, heat to 65° C. under stirring, add 28 parts of peracetic acid dropwise at a rate of 1.6 ml / min, keep the temperature constant, and stir for 5.5 h to obtain epoxy palm oil;

[0046] S22. Add 2 parts of tetrabutylammonium bromide and 0.5 parts of L-ascorbic acid to 90 parts of epoxy palm oil by weight, introduce carbon dioxide gas, control the stirring rate to 280 rpm, stir at 2 MPa and 85° C. for 7 hours to obtain carbonated epoxy palm oil, add 22 parts of an amine cross-linking agent and 0.7 parts of 1,8-diazabicyclo[5.4.0]undec-7-ene, and continue stirring at 145° C. for 25 hours to obtain a polyurethane prepolymer, wherein the amine cross-linking agent is composed of isophorone diamine and 4,4'-diaminodiphenyl disulfide in a molar ratio of 2:1;

[0047] S3, preparing flexible polyurethane synthetic adhesive:

[0048] Functional filler, polyurethane prepolymer, polyoxypropylene glycerol ether and sodium dodecylbenzene sulfonate are dispersed in deionized water, the stirring rate is controlled to be 180 rpm, and the emulsion is obtained after stirring at room temperature for 55 minutes. Hydroxyethyl acrylate and dibutyltin dilaurate are added, and stirring is continued for 2.5 hours at 65°C, and then 2-hydroxy-2-methyl-1-phenyl-1-propanone is added. After stirring evenly, a flexible polyurethane synthetic adhesive is obtained.

[0049] Example 3

[0050] A method for preparing a flexible polyurethane synthetic adhesive comprises the following preparation steps:

[0051] S1. Preparation of functional fillers:

[0052] S11, dispersing graphene oxide in N,N-dimethylformamide, ultrasonically treating at 60kHz for 30min, adding p-toluenesulfonyl chloride and 4-dimethylaminopyridine, introducing nitrogen protection, controlling the stirring rate to 300rpm, stirring at 50°C for 5h, centrifuging, washing and drying to obtain active graphene oxide, wherein the mass ratio of graphene oxide, N,N-dimethylformamide, p-toluenesulfonyl chloride and 4-dimethylaminopyridine is 3:40:8:0.5;

[0053] S12, dissolving polytetramethylene ether glycol in N,N-dimethylformamide, adding 12% by mass of active graphene oxide dispersion and potassium carbonate, introducing nitrogen protection, controlling the stirring rate to 300 rpm, stirring continuously for 4 hours at 100° C., centrifugally washing and drying to obtain a functional filler, wherein the mass ratio of polytetramethylene ether glycol, N,N-dimethylformamide, active graphene oxide dispersion and potassium carbonate is 5:40:2:0.45;

[0054] S2. Preparation of polyurethane prepolymer:

[0055] S21, adding 100 parts of palm oil and 3 parts of tetrabutylammonium bromide into a reactor by weight, controlling the stirring rate to 350 rpm, heating to 70° C. under stirring, adding 30 parts of peracetic acid dropwise at a rate of 2 ml / min, keeping the temperature constant, and stirring for 4 hours to obtain epoxy palm oil;

[0056] S22. Add 2 parts of tetrabutylammonium bromide and 0.6 parts of L-ascorbic acid to 100 parts of epoxy palm oil by weight, introduce carbon dioxide gas, control the stirring rate to 350 rpm, stir at 2.2 MPa and 90° C. for 6 hours to obtain carbonated epoxy palm oil, add 25 parts of an amino cross-linking agent and 0.8 parts of 1,8-diazabicyclo[5.4.0]undec-7-ene, and continue stirring at 150° C. for 24 hours to obtain a polyurethane prepolymer, wherein the amino cross-linking agent consists of isophorone diamine and 4,4'-diaminodiphenyl disulfide in a molar ratio of 3:1;

[0057] S3, preparing flexible polyurethane synthetic adhesive:

[0058] Functional filler, polyurethane prepolymer, polydimethylsiloxane and sodium dodecylbenzene sulfonate are dispersed in deionized water, the stirring rate is controlled to be 150-200 rpm, and the emulsion is obtained after stirring at room temperature for 40-60 minutes. Hydroxyethyl acrylate and dibutyltin dilaurate are added, and the stirring is continued for 2-3 hours at 60-70°C, and then benzoin dimethyl ether is added, and the flexible polyurethane synthetic adhesive is obtained after stirring evenly.

[0059] Example 4

[0060] A method for preparing a flexible polyurethane synthetic adhesive comprises the following preparation steps:

[0061] S1. Preparation of functional fillers:

[0062] S11, dispersing graphene oxide in N,N-dimethylformamide, ultrasonically treating at 60kHz for 30min, adding p-toluenesulfonyl chloride and 4-dimethylaminopyridine, introducing nitrogen protection, controlling the stirring rate to 300rpm, stirring at 50°C for 5h, centrifuging, washing and drying to obtain active graphene oxide, wherein the mass ratio of graphene oxide, N,N-dimethylformamide, p-toluenesulfonyl chloride and 4-dimethylaminopyridine is 2:38:8:0.5;

[0063] S12, dissolving polytetramethylene ether glycol in N,N-dimethylformamide, adding 10% by mass of active graphene oxide dispersion and potassium carbonate, introducing nitrogen protection, controlling the stirring rate to 300 rpm, stirring continuously for 4 hours at 95° C., centrifugally washing and drying to obtain a functional filler, wherein the mass ratio of polytetramethylene ether glycol, N,N-dimethylformamide, active graphene oxide dispersion and potassium carbonate is 4:40:2:0.45;

[0064] S2. Preparation of polyurethane prepolymer:

[0065] S21, adding 98 parts of palm oil and 2 parts of tetrabutylammonium bromide to a reactor by weight, controlling the stirring rate to 300 rpm, heating to 68° C. under stirring, adding 26 parts of peracetic acid dropwise at a rate of 2 ml / min, keeping the temperature constant, and stirring for 4.5 hours to obtain epoxy palm oil;

[0066] S22. Add 2 parts of tetrabutylammonium bromide and 0.5 parts of L-ascorbic acid to 98 parts of epoxy palm oil by weight, introduce carbon dioxide gas, control the stirring rate to 300 rpm, stir at 2 MPa and 90° C. for 6 hours to obtain carbonated epoxy palm oil, add 24 parts of an amino cross-linking agent and 0.8 parts of 1,8-diazabicyclo[5.4.0]undec-7-ene, and continue stirring at 150° C. for 24 hours to obtain a polyurethane prepolymer, wherein the amino cross-linking agent consists of isophorone diamine and 4,4'-diaminodiphenyl disulfide in a molar ratio of 3:1;

[0067] S3, preparing flexible polyurethane synthetic adhesive:

[0068] Functional filler, polyurethane prepolymer, defoaming agent polyoxypropylene glycerol ether and sodium dodecylbenzene sulfonate are dispersed in deionized water, the stirring rate is controlled to be 180 rpm, and the emulsion is obtained after stirring at room temperature for 45 minutes. Hydroxyethyl acrylate and dibutyltin dilaurate are added, and stirring is continued at 70°C for 2 hours. Then, benzoin dimethyl ether is added and stirred evenly to obtain a flexible polyurethane synthetic adhesive.

[0069] Comparative Example 1

[0070] A method for preparing a flexible polyurethane synthetic adhesive comprises the following preparation steps:

[0071] S1. Preparation of polyurethane prepolymer:

[0072] S11, adding 98 parts of palm oil and 2 parts of tetrabutylammonium bromide into a reactor by weight, controlling the stirring rate to 300 rpm, heating to 68° C. under stirring, adding 26 parts of peracetic acid dropwise at a rate of 2 ml / min, keeping the temperature constant, and stirring for 4.5 hours to obtain epoxy palm oil;

[0073] S12, by weight, adding 2 parts of tetrabutylammonium bromide and 0.5 parts of L-ascorbic acid to 98 parts of epoxy palm oil, introducing carbon dioxide gas, controlling the stirring rate to 300 rpm, stirring at 2 MPa and 90° C. for 6 hours to obtain carbonated epoxy palm oil, adding 24 parts of an amino cross-linking agent and 0.8 parts of 1,8-diazabicyclo[5.4.0]undec-7-ene, and continuously stirring at 150° C. for 24 hours to obtain a polyurethane prepolymer, wherein the amino cross-linking agent is composed of isophorone diamine and 4,4'-diaminodiphenyl disulfide in a molar ratio of 3:1;

[0074] S2. Preparation of flexible polyurethane synthetic adhesive:

[0075] Disperse the polyurethane prepolymer, polyoxypropylene glycerol ether and sodium dodecylbenzene sulfonate in deionized water, control the stirring rate to 180 rpm, stir at room temperature for 45 minutes to obtain an emulsion, add hydroxyethyl acrylate and dibutyltin dilaurate, continue stirring at 70°C for 2 hours, then add benzoin dimethyl ether and stir evenly to obtain a flexible polyurethane synthetic adhesive.

[0076] Comparative Example 2

[0077] A method for preparing a flexible polyurethane synthetic adhesive comprises the following preparation steps:

[0078] S1. Preparation of functional fillers:

[0079] Graphene oxide was dispersed in N,N-dimethylformamide, and then p-toluenesulfonyl chloride and 4-dimethylaminopyridine were added after ultrasonic treatment at 60kHz for 30 minutes, and nitrogen was introduced for protection. The stirring rate was controlled to be 300rpm, and the functional filler was obtained after stirring at 50°C for 5 hours and then centrifuged, washed and dried, wherein the mass ratio of graphene oxide, N,N-dimethylformamide, p-toluenesulfonyl chloride and 4-dimethylaminopyridine was 2:38:8:0.5;

[0080] S2. Preparation of polyurethane prepolymer:

[0081] S21, adding 98 parts of palm oil and 2 parts of tetrabutylammonium bromide to a reactor by weight, controlling the stirring rate to 300 rpm, heating to 68° C. under stirring, adding 26 parts of peracetic acid dropwise at a rate of 2 ml / min, keeping the temperature constant, and stirring for 4.5 hours to obtain epoxy palm oil;

[0082] S22. Add 2 parts of tetrabutylammonium bromide and 0.5 parts of L-ascorbic acid to 98 parts of epoxy palm oil by weight, introduce carbon dioxide gas, control the stirring rate to 300 rpm, stir at 2 MPa and 90° C. for 6 hours to obtain carbonated epoxy palm oil, add 24 parts of an amino cross-linking agent and 0.8 parts of 1,8-diazabicyclo[5.4.0]undec-7-ene, and continue stirring at 150° C. for 24 hours to obtain a polyurethane prepolymer, wherein the amino cross-linking agent consists of isophorone diamine and 4,4'-diaminodiphenyl disulfide in a molar ratio of 3:1;

[0083] S3, preparing flexible polyurethane synthetic adhesive:

[0084] Functional filler, polyurethane prepolymer, polyoxypropylene glycerol ether and sodium dodecylbenzene sulfonate are dispersed in deionized water, the stirring rate is controlled to be 180 rpm, and the emulsion is obtained after stirring at room temperature for 45 minutes. Hydroxyethyl acrylate and dibutyltin dilaurate are added, and stirring is continued at 70°C for 2 hours. Then, benzoin dimethyl ether is added and stirred evenly to obtain a flexible polyurethane synthetic adhesive.

[0085] Comparative Example 3

[0086] A method for preparing a flexible polyurethane synthetic adhesive comprises the following preparation steps:

[0087] S1. Preparation of functional fillers:

[0088] S11, dispersing graphene oxide in N,N-dimethylformamide, ultrasonically treating at 60kHz for 30min, adding p-toluenesulfonyl chloride and 4-dimethylaminopyridine, introducing nitrogen protection, controlling the stirring rate to 300rpm, stirring at 50°C for 5h, centrifuging, washing and drying to obtain active graphene oxide, wherein the mass ratio of graphene oxide, N,N-dimethylformamide, p-toluenesulfonyl chloride and 4-dimethylaminopyridine is 2:38:8:0.5;

[0089] S12, dissolving polytetramethylene ether glycol in N,N-dimethylformamide, adding 10% by mass of active graphene oxide dispersion and potassium carbonate, introducing nitrogen protection, controlling the stirring rate to 300 rpm, stirring continuously for 4 hours at 95° C., centrifugally washing and drying to obtain a functional filler, wherein the mass ratio of polytetramethylene ether glycol, N,N-dimethylformamide, active graphene oxide dispersion and potassium carbonate is 4:40:2:0.45;

[0090] S2. Preparation of polyurethane prepolymer:

[0091] S21, adding 98 parts of palm oil and 2 parts of tetrabutylammonium bromide to a reactor by weight, controlling the stirring rate to 300 rpm, heating to 68° C. under stirring, adding 26 parts of peracetic acid dropwise at a rate of 2 ml / min, keeping the temperature constant, and stirring for 4.5 hours to obtain epoxy palm oil;

[0092] S22. Add 2 parts of tetrabutylammonium bromide to 98 parts of epoxy palm oil by weight, introduce carbon dioxide gas, control the stirring rate to 300 rpm, stir at 2 MPa and 90° C. for 6 hours to obtain carbonated epoxy palm oil, add 24 parts of an amine cross-linking agent and 0.8 parts of 1,8-diazabicyclo[5.4.0]undec-7-ene, and continue stirring at 150° C. for 24 hours to obtain a polyurethane prepolymer, wherein the amine cross-linking agent consists of isophorone diamine and 4,4'-diaminodiphenyl disulfide in a molar ratio of 3:1;

[0093] S3, preparing flexible polyurethane synthetic adhesive:

[0094] Functional filler, polyurethane prepolymer, polyoxypropylene glycerol ether and sodium dodecylbenzene sulfonate are dispersed in deionized water, the stirring rate is controlled to be 180 rpm, and the emulsion is obtained after stirring at room temperature for 45 minutes. Hydroxyethyl acrylate and dibutyltin dilaurate are added, and stirring is continued at 70°C for 2 hours. Then, benzoin dimethyl ether is added and stirred evenly to obtain a flexible polyurethane synthetic adhesive.

[0095] Comparative Example 4

[0096] A method for preparing a flexible polyurethane synthetic adhesive comprises the following preparation steps:

[0097] S1. Preparation of functional fillers:

[0098] S11, dispersing graphene oxide in N,N-dimethylformamide, ultrasonically treating at 60kHz for 30min, adding p-toluenesulfonyl chloride and 4-dimethylaminopyridine, introducing nitrogen protection, controlling the stirring rate to 300rpm, stirring at 50°C for 5h, centrifuging, washing and drying to obtain active graphene oxide, wherein the mass ratio of graphene oxide, N,N-dimethylformamide, p-toluenesulfonyl chloride and 4-dimethylaminopyridine is 2:38:8:0.5;

[0099] S12, dissolving polytetramethylene ether glycol in N,N-dimethylformamide, adding 10% by mass of active graphene oxide dispersion and potassium carbonate, introducing nitrogen protection, controlling the stirring rate to 300 rpm, stirring continuously for 4 hours at 95° C., centrifugally washing and drying to obtain a functional filler, wherein the mass ratio of polytetramethylene ether glycol, N,N-dimethylformamide, active graphene oxide dispersion and potassium carbonate is 4:40:2:0.45;

[0100] S2. Preparation of polyurethane prepolymer:

[0101] S21, adding 98 parts of palm oil and 2 parts of tetrabutylammonium bromide to a reactor by weight, controlling the stirring rate to 300 rpm, heating to 68° C. under stirring, adding 26 parts of peracetic acid dropwise at a rate of 2 ml / min, keeping the temperature constant, and stirring for 4.5 hours to obtain epoxy palm oil;

[0102] S22, by weight, adding 2 parts of tetrabutylammonium bromide and 0.5 parts of L-ascorbic acid to 98 parts of epoxy palm oil, introducing carbon dioxide gas, controlling the stirring rate to 300 rpm, stirring at 2 MPa and 90° C. for 6 h to obtain carbonated epoxy palm oil, adding 24 parts of isophorone diamine and 0.8 parts of 1,8-diazabicyclo[5.4.0]undec-7-ene, and continuously stirring at 150° C. for 24 h to obtain a polyurethane prepolymer;

[0103] S3, preparing flexible polyurethane synthetic adhesive:

[0104] Functional filler, polyurethane prepolymer, defoaming agent polyoxypropylene glycerol ether and sodium dodecylbenzene sulfonate are dispersed in deionized water, the stirring rate is controlled to be 180 rpm, and the emulsion is obtained after stirring at room temperature for 45 minutes. Hydroxyethyl acrylate and dibutyltin dilaurate are added, and stirring is continued at 70°C for 2 hours. Then, benzoin dimethyl ether is added and stirred evenly to obtain a flexible polyurethane synthetic adhesive.

[0105] Comparative Example 5

[0106] A method for preparing a flexible polyurethane synthetic adhesive comprises the following preparation steps:

[0107] S1. Preparation of functional fillers:

[0108] S11, dispersing graphene oxide in N,N-dimethylformamide, ultrasonically treating at 60kHz for 30min, adding p-toluenesulfonyl chloride and 4-dimethylaminopyridine, introducing nitrogen protection, controlling the stirring rate to 300rpm, stirring at 50°C for 5h, centrifuging, washing and drying to obtain active graphene oxide, wherein the mass ratio of graphene oxide, N,N-dimethylformamide, p-toluenesulfonyl chloride and 4-dimethylaminopyridine is 2:38:8:0.5;

[0109] S12, dissolving polytetramethylene ether glycol in N,N-dimethylformamide, adding 10% by mass of active graphene oxide dispersion and potassium carbonate, introducing nitrogen protection, controlling the stirring rate to 300 rpm, stirring continuously for 4 hours at 95° C., centrifugally washing and drying to obtain a functional filler, wherein the mass ratio of polytetramethylene ether glycol, N,N-dimethylformamide, active graphene oxide dispersion and potassium carbonate is 4:40:2:0.45;

[0110] S2. Preparation of polyurethane prepolymer:

[0111] S21, adding 98 parts of palm oil and 2 parts of tetrabutylammonium bromide to a reactor by weight, controlling the stirring rate to 300 rpm, heating to 68° C. under stirring, adding 26 parts of peracetic acid dropwise at a rate of 2 ml / min, keeping the temperature constant, and stirring for 4.5 hours to obtain epoxy palm oil;

[0112] S22. Add 2 parts of tetrabutylammonium bromide and 0.5 parts of L-ascorbic acid to 98 parts of epoxy palm oil by weight, introduce carbon dioxide gas, control the stirring rate to 300 rpm, stir at 2 MPa and 90° C. for 6 hours to obtain carbonated epoxy palm oil, add 24 parts of an amino cross-linking agent and 0.8 parts of 1,8-diazabicyclo[5.4.0]undec-7-ene, and continue stirring at 150° C. for 24 hours to obtain a polyurethane prepolymer, wherein the amino cross-linking agent consists of isophorone diamine and 4,4'-diaminodiphenyl disulfide in a molar ratio of 3:1;

[0113] S3, preparing flexible polyurethane synthetic adhesive:

[0114] Functional filler, polyurethane prepolymer, defoamer polyoxypropylene glycerol ether and sodium dodecylbenzene sulfonate were dispersed in deionized water, the stirring rate was controlled to be 180 rpm, and an emulsion was obtained after stirring at room temperature for 45 minutes. Benzoin dimethyl ether was added and stirred evenly to obtain a flexible polyurethane synthetic adhesive.

[0115] Comparative Example 6

[0116] A method for preparing a flexible polyurethane synthetic adhesive comprises the following preparation steps:

[0117] S1. Preparation of functional fillers:

[0118] S11, dispersing graphene oxide in N,N-dimethylformamide, ultrasonically treating at 60kHz for 30min, adding p-toluenesulfonyl chloride and 4-dimethylaminopyridine, introducing nitrogen protection, controlling the stirring rate to 300rpm, stirring at 50°C for 5h, centrifuging, washing and drying to obtain active graphene oxide, wherein the mass ratio of graphene oxide, N,N-dimethylformamide, p-toluenesulfonyl chloride and 4-dimethylaminopyridine is 2:38:8:0.5;

[0119] S12, dissolving polytetramethylene ether glycol in N,N-dimethylformamide, adding 10% by mass of active graphene oxide dispersion and potassium carbonate, introducing nitrogen protection, controlling the stirring rate to 300 rpm, stirring continuously for 4 hours at 95° C., centrifugally washing and drying to obtain a functional filler, wherein the mass ratio of polytetramethylene ether glycol, N,N-dimethylformamide, active graphene oxide dispersion and potassium carbonate is 4:40:2:0.45;

[0120] S2. Preparation of polyurethane prepolymer:

[0121] S21, adding 98 parts of palm oil and 2 parts of tetrabutylammonium bromide to a reactor by weight, controlling the stirring rate to 300 rpm, heating to 68° C. under stirring, adding 26 parts of peracetic acid dropwise at a rate of 2 ml / min, keeping the temperature constant, and stirring for 4.5 hours to obtain epoxy palm oil;

[0122] S22. Add 2 parts of tetrabutylammonium bromide and 0.5 parts of L-ascorbic acid to 98 parts of epoxy palm oil by weight, introduce carbon dioxide gas, control the stirring rate to 300 rpm, stir at 2 MPa and 90° C. for 6 hours to obtain carbonated epoxy palm oil, add 24 parts of an amino cross-linking agent and 0.8 parts of 1,8-diazabicyclo[5.4.0]undec-7-ene, and continue stirring at 150° C. for 24 hours to obtain a polyurethane prepolymer, wherein the amino cross-linking agent consists of isophorone diamine and 4,4'-diaminodiphenyl disulfide in a molar ratio of 3:1;

[0123] S3, preparing flexible polyurethane synthetic adhesive:

[0124] Functional filler, polyurethane prepolymer, defoaming agent polyoxypropylene glycerol ether and sodium dodecylbenzene sulfonate are dispersed in deionized water, the stirring rate is controlled to be 180 rpm, and the emulsion is obtained after stirring at room temperature for 45 minutes. Hydroxyethyl acrylate and dibutyltin dilaurate are added, and the flexible polyurethane synthetic adhesive is obtained after continuous stirring at 70°C for 2 hours.

[0125] Performance Testing

[0126] The performance tests were performed on the flexible polyurethane synthetic adhesives prepared in Examples 1-4 and Comparative Examples 1-6:

[0127] 1. Test of bonding strength: Apply the synthetic glue on an aluminum sheet with a size of 100 mm × 25 mm, with a coating size of about 20 mm × 25 mm. After natural curing in the air, overlap the two aluminum sheets at the position where the emulsion is applied and stick them together. Fix them with clips and put them in an oven at 80°C to dry for 48 hours. Then test the tensile strength in a universal material testing machine. The bonding strength is evaluated with the maximum tensile strength. The test results are shown in Table 1.

[0128] 2. High-low temperature and humidity alternating aging test: refer to GB / T2423.1-2008 and GB / T2790-1995 standard methods for determination. The experimental samples are placed in a high-low temperature and humidity cycle test box under specified conditions, and placed at 80℃, 95%RH for 4 hours, then cooled to -40℃ within 2 hours, and continued to be placed at -40℃ for 4 hours, and then heated to 80℃, 95%RH within 2 hours. The test cycle is 240 hours. The test results are shown in Table 1.

[0129] 3. UV aging test: refer to ASTMG 154-12a and ASTM G 151-10 standard methods for determination, the UV wavelength is 313nm, 4h under UV conditions and 4h under condensation conditions as one cycle, the temperature is 60℃, the irradiance is 0.71±0.02W / m2 / nm, the temperature during condensation is 50±3℃, the test cycle is 240h, and the test results are shown in Table 1.

[0130] Table 1

[0131]

[0132]

[0133] From the results shown in Table 1 above, it can be seen that the comprehensive performance of the flexible polyurethane synthetic adhesives prepared in Examples 1-4 of the present invention is much better than that of Comparative Examples 1-6.

[0134] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a flexible polyurethane synthetic adhesive, for preparing the flexible polyurethane synthetic adhesive according to claim 1, characterized in that: The preparation method comprises the following steps: S1. Preparation of functional fillers: S11, dispersing graphene oxide in N,N-dimethylformamide, adding p-toluenesulfonyl chloride and 4-dimethylaminopyridine after ultrasonic treatment for 30-60 minutes, introducing nitrogen protection, stirring continuously at 40-50° C. for 5-7 hours, centrifugally washing and drying to obtain active graphene oxide; S12, dissolving polytetramethylene ether glycol in N,N-dimethylformamide, adding active graphene oxide dispersion and potassium carbonate, introducing nitrogen protection, stirring continuously at 80-100° C. for 4-6 hours, and then centrifugally washing and drying to obtain a functional filler; S2. Preparation of polyurethane prepolymer: S21, adding palm oil and tetrabutylammonium bromide into a reaction kettle, heating to 60-70° C. under stirring, adding peracetic acid dropwise, maintaining the temperature constant and stirring for 4-6 hours to obtain epoxy palm oil; S22, adding tetrabutylammonium bromide and L-ascorbic acid to epoxy palm oil, introducing carbon dioxide gas, stirring continuously at 2-3 MPa and 80-90° C. for 6-8 hours to obtain carbonated epoxy palm oil, adding an amine crosslinking agent and 1,8-diazabicyclo[5.4.0]undec-7-ene, stirring continuously at 140-150° C. for 24-28 hours to obtain a polyurethane prepolymer; S3, preparing flexible polyurethane synthetic adhesive: Functional filler, polyurethane prepolymer, defoamer and sodium dodecylbenzene sulfonate are dispersed in deionized water, stirred at room temperature for 40-60 minutes to obtain an emulsion, hydroxyethyl acrylate and dibutyltin dilaurate are added, stirring is continued at 60-70°C for 2-3 hours, and then a photoinitiator is added, and flexible polyurethane synthetic adhesive is obtained after stirring evenly.

2. The method for preparing the flexible polyurethane synthetic adhesive according to claim 2, characterized in that: In the step S11, the mass ratio of graphene oxide, N,N-dimethylformamide, p-toluenesulfonyl chloride and 4-dimethylaminopyridine is 1-3:35-40:5-8:0.3-0.

5.

3. The method for preparing the flexible polyurethane synthetic adhesive according to claim 2, characterized in that: In the step S12, the mass ratio of polytetramethylene ether glycol, N,N-dimethylformamide, active graphene oxide dispersion and potassium carbonate is 3-5:35-40:1-2:0.3-0.

45.

4. The method for preparing the flexible polyurethane synthetic adhesive according to claim 2, characterized in that: In step S21, the components include 80-100 parts of palm oil, 1-3 parts of tetrabutylammonium bromide and 25-30 parts of peracetic acid by weight.

5. The method for preparing the flexible polyurethane synthetic adhesive according to claim 2, characterized in that: In the step S22, the amine cross-linking agent is composed of isophorone diamine and 4,4'-diaminodiphenyl disulfide in a molar ratio of 1-3:

1.

6. The method for preparing the flexible polyurethane synthetic adhesive according to claim 2, characterized in that: In step S22, the components by weight include 80-100 parts of epoxy palm oil, 1-2 parts of tetrabutylammonium bromide, 0.4-0.6 parts of L-ascorbic acid, 20-25 parts of an amino crosslinking agent, and 0.6-0.8 parts of 1,8-diazabicyclo[5.4.0]undec-7-ene.

7. The method for preparing the flexible polyurethane synthetic adhesive according to claim 2, characterized in that: The defoaming agent in step S3 is at least one of polydimethylsiloxane, polyoxypropylene glycerol ether and polysorbate.

8. The method for preparing the flexible polyurethane synthetic adhesive according to claim 2, characterized in that: In step S3, the photoinitiator is at least one of benzoin dimethyl ether, 2-hydroxy-2-methyl-1-phenyl-1-propanone and 1-hydroxycyclohexyl phenyl ketone.

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