Preparation method of waterborne polyurethane-acrylate adhesive for fabric compounding

Abstract

The invention provides a preparation method of a waterborne polyurethane-acrylate adhesive for fabric compounding, and belongs to the technical field of adhesive preparation. The preparation method comprises the following steps: synthesizing a polyurethane prepolymer from aliphatic polycarbonate-polyether polyol, a hydrophilic chain extender and isocyanate, then carrying out partial end capping by using a hydroxyl acrylate monomer, and carrying out salt formation by using a neutralizing agent, low-temperature chain extension by using a post-chain extender and seed emulsion polymerization to generate the waterborne polyurethane-acrylate emulsion with a core-shell structure. Through selection of the types of polyurethane-acrylate monomers and optimization of the proportion of chain links, the synthesized composite adhesive has pressure sensitivity, provides initial strength, and can improve the bonding strength, washing resistance and other properties of a composite fabric through crosslinking with a curing agent in the later use process.

Description

Technical Field

[0001] The invention belongs to the technical field of adhesive preparation, in particular to a method for preparing a water-based polyurethane-acrylate adhesive for fabric composite. Background Art

[0002] Polyurethane has received extensive attention due to its excellent performance, and the global restrictions on volatile solvents have promoted the development and utilization of waterborne polyurethane. Waterborne polyurethane uses water as a dispersion medium, and has the advantages of low toxicity, non-flammability, low pollution, energy saving, and safety. Compared with solvent-based polyurethane, it has a brighter development prospect. However, waterborne polyurethane has disadvantages such as slow drying, low initial viscosity, and poor water washing resistance. In particular, textile composite fabrics have high requirements for water washing resistance. Therefore, many scholars have done a lot of work on the modification of waterborne polyurethane emulsions, among which waterborne acrylate-modified polyurethane emulsions have better comprehensive performance.

[0003] The most typical modification methods are physical blending modification and copolymerization modification. The physical mixing method is relatively simple. The invention patent CN201610718198.6 discloses a method for preparing a carbon dioxide-based waterborne polyurethane-polyacrylate composite emulsion and its composite coating. The coating prepared by this technology is a transparent waterborne polyurethane-acrylate coating, but the two are only mixed in the form of an interpenetrating network structure, and the mechanical properties are not significantly improved and the stability of the system is poor. The invention patent CN103059230B discloses a modified waterborne polyurethane, which is to first prepare a waterborne polyurethane, and then modify the waterborne polyurethane dispersion with styrene and acrylic acid to obtain an acrylic acid-modified waterborne polyurethane with an interpenetrating network structure. The interpenetrating network forms a topological bond, not a true covalent bond, which belongs to physical modification. Compared with the physical modification method, the chemical copolymerization method has great advantages in solving the compatibility of PU and PA and improving the comprehensive performance of the emulsion. The invention patents with publication number CN101906192B all provide a method for preparing an aqueous polyurethane-acrylate composite emulsion, which synthesizes unsaturated polyurethane monomers with double bonds and copolymerizes acrylate monomers without the need for additional solvents and emulsifiers. However, there are problems such as long reaction time, low grafting rate of polyurethane and acrylate monomers, easy retention of residual monomers, and low solid content of the product.

[0004] Therefore, there is an urgent need to develop a new type of environmentally friendly and high-performance water-based polyurethane adhesive. Summary of the invention

[0005] The purpose of the present invention is to solve the above problems in the prior art and to propose a method for preparing a water-based polyurethane-acrylate adhesive for fabric composite.

[0006] The purpose of the present invention can be achieved through the following technical scheme: A method for preparing an aqueous polyurethane-acrylate adhesive for fabric composite, comprising the following steps: S1 Preparation of aqueous polyurethane prepolymer: S1.1 Dehydration pretreatment: After the aliphatic polycarbonate-polyether polyol PPCD, nonionic polyol N120, hydrophilic chain extender and antioxidant are mixed evenly, a dehydration operation is performed to obtain a dehydrated mixture; the hydrophilic chain extender is DMPA or DMBA; S1.2 Isocyanate polycondensation reaction: After the dehydrated mixture is cooled, isocyanate is added to the dehydrated mixture for polycondensation reaction to obtain an isocyanate polycondensation reaction mixture; the isocyanate is specifically one of IPDI, hydrogenated MDI, MDI-50 and HDI; S1.3 Partial end-capping reaction: After the mixture after the isocyanate polycondensation reaction is cooled, a hydroxy acrylate monomer is added to the mixture after the isocyanate polycondensation reaction A partial end-capping reaction is carried out, and after the reaction is completed, a partially end-capping reaction mixture is obtained; the hydroxy acrylate monomer is specifically a HEA monomer or an HPA monomer; S1.4 Salt formation: after the partial end-capping reaction mixture is cooled, a neutralizing agent and a viscosity adjusting agent are added to the partial end-capping reaction mixture to carry out a salt-forming reaction to obtain a salt-forming reaction mixture; the neutralizing agent is triethylamine; S1.5 High-speed dispersion: after the salt-forming reaction mixture is cooled, it is placed in a cold water bath device, and then deionized water is added, followed by high-speed dispersion treatment to obtain an initial dispersed mixture; S1.6 Post-chain extender addition: after the initial dispersed mixture is added dropwise with an aqueous solution of a post-chain extender to react to obtain an initial target mixture; the post-chain extender is ethylenediamine; S1.7 Post-treatment: the initial target mixture is subjected to a high-speed dispersion treatment, and after the dispersion is completed, filtering operations and removing viscosity adjusting agents are performed in sequence to obtain a waterborne polyurethane prepolymer; S2 Synthesis of waterborne polyurethane-acrylate emulsion: S2.1 Polymerization reaction: The waterborne polyurethane prepolymer, part of the acrylate monomer mixture, the chain initiator and deionized water are mixed evenly and then subjected to polymerization reaction; after the reaction is completed, the remaining acrylate monomer mixture is added dropwise to continue the polymerization reaction. After the reaction is completed, a polymerization reaction mixture is obtained; the acrylate monomer mixture includes ethyl acrylate, isooctyl acrylate, n-butyl acrylate and hydroxy acrylate; the chain initiator is azobisisobutyronitrile; S2.2 Addition of additives: After the mixture after the polymerization reaction is cooled, a defoamer and a leveling agent are added, and then stirred. After stirring until uniform, a waterborne polyurethane-acrylate adhesive is obtained.

[0007] Preferably, in step S1, the antioxidant is antioxidant 1010; and the viscosity adjusting agent is acetone.

[0008] Preferably, in step S1, the weight ratio of aliphatic polycarbonate-polyether polyol PPCD: nonionic polyol N120: hydrophilic chain extender: isocyanate: antioxidant 1010: hydroxy acrylate monomer: neutralizer: post-chain extender is 65-80:1-5:2-5:20-30:0.1-0.5:2-5:1-3:1-3; the amount of deionized water used is 2-2.4 times the sum of the weight of aliphatic polycarbonate-polyether polyol PPCD, nonionic polyol N120, hydrophilic chain extender, isocyanate, antioxidant 1010, hydroxy acrylate monomer, neutralizer and post-chain extender.

[0009] In the process of removing the viscosity adjusting agent, acetone is removed by vacuum distillation.

[0010] In the aqueous solution of the post-chain extender, the concentration of ethylenediamine is 50%.

[0011] Preferably, in step S2.1, the weight ratio of the partial acrylate monomer mixture to the remaining acrylate monomer mixture is 1:2.

[0012] Preferably, in step S1.1, the dehydration operation is performed under vacuum conditions, the temperature of the dehydration operation is 110-120° C., and the moisture content in the dehydrated mixture is less than 300 ppm.

[0013] Preferably, in step S1.2, the target temperature of the cooling operation is lower than 60°C, and the condensation reaction temperature is 100-110°C; in step S1.3, the target temperature of the cooling operation is 80°C, and the partial end-capping reaction temperature is 80°C; in step S1.4, the target temperature of the cooling operation is 55-60°C, and the salt-forming reaction temperature is 55-60°C; in step S1.5, the target temperature of the cooling operation is not higher than 30°C, and the temperature of the cold water in the cold water bath device is 5-15°C; in step S2.1, the polymerization reaction temperature is 80-85°C; in step S2.2, the target temperature of the cooling operation is lower than 40°C.

[0014] Preferably, the leveling agent is specifically one of Tego410 leveling agent, Tego425 leveling agent and Runhe T1008 leveling agent; the defoaming agent is specifically one of 810S defoaming agent and BYK-024 defoaming agent.

[0015] According to the weight ratio, the waterborne polyurethane prepolymer: ethyl acrylate: isooctyl acrylate: n-butyl acrylate: hydroxy acrylate: chain initiator: defoamer: leveling agent: deionized water is 100:10-15:1-3:3-6:1-3:0.05-1:0.05-1:0.05-1:35-50.

[0016] Preferably, in step S1.2, the polycondensation reaction time is 2 hours; in step S1.3, the partial end-capping reaction time is 30 minutes; in step S1.4, the salt-forming reaction time is 30 minutes.

[0017] Preferably, in step S1.5 and step S1.7, the stirring speed of the high-speed dispersion treatment is 1000-15000 r / min; Preferably, in step S1.7, a 200-mesh filter is used in the filtering operation; The purpose of dehydration under vacuum conditions is as follows: During the polyurethane synthesis process, the presence of water will lead to side reactions, especially when reacting with isocyanate, water reacts with isocyanate to generate carbon dioxide and amine compounds, affecting the structure and properties of the final product. Through dehydration treatment, this undesirable side reaction can be avoided.

[0018] Hydrophilic chain extenders, DMPA (bis(2-hydroxyethyl)aminoacetic acid) or DMBA (bis(2-hydroxyethyl)aminobutyric acid), play two key roles in the synthesis of waterborne polyurethanes: Improve water solubility and hydrophilicity: Hydrophilic chain extenders can introduce hydrophilic groups into polyurethane molecules, thereby improving the water solubility and hydrophilicity of polyurethanes. This is very important for the stability of the subsequent emulsion, because waterborne polyurethane emulsions need to have good water dispersibility and stability. Enhanced dispersibility and stability: In water-based systems, hydrophilic chain extenders can effectively enhance the water dispersibility of polymers and promote the dispersion and stability of adhesives. It helps to form a more uniform and delicate dispersion system during the reaction process and avoid aggregation or precipitation of polyurethane prepolymers in water.

[0019] Improve the performance of the final product: The introduction of hydrophilic groups not only enhances the compatibility of polyurethane with aqueous media, but also has a positive impact on the adhesion, flexibility and mechanical properties of the final water-based adhesive.

[0020] The role of antioxidants: Antioxidant 1010 is mainly used to prevent the degradation or failure of raw materials and substances produced in the polymerization reaction due to oxidation. The role of antioxidants in the preparation of waterborne polyurethane-acrylate adhesives is mainly reflected in the following aspects: Preventing oxidation reactions: During the synthesis process, polyurethane and acrylate may undergo oxidation reactions due to the presence of oxygen, especially during high-temperature reactions, resulting in degradation of the molecular chain and deterioration of polymer properties. Antioxidants inhibit oxidation reactions to ensure that the molecular chains of polymers are not excessively degraded, thereby ensuring the performance of the final product. Improving thermal stability: Antioxidant 1010 has strong thermal stability and can protect polymers in the reaction system from oxidation under high temperature conditions, avoiding the degradation of reaction intermediates or polymers caused by oxidation. Improving weather resistance: The addition of antioxidants also helps to improve the long-term stability of the adhesive during use, especially when exposed to air, and increase the weather resistance and service life of the product.

[0021] The addition of hydrophilic chain extenders is mainly to improve the hydrophilicity and water dispersibility of waterborne polyurethane, enhance the stability of adhesives and the performance of the final product. The addition of antioxidants is to prevent oxidation reactions, protect the polymers in the reaction from oxidative degradation, and ensure the thermal stability and weather resistance of the product.

[0022] Definition of end-capping reaction: End-capping reaction refers to the termination or partial termination of the reactive activity of the polymer chain by adding a blocking group through a certain chemical reaction. In polyurethane synthesis, the end-capping process is completed by adding a compound with an active group to react with the unreacted isocyanate group (-NCO). End-capping can limit the chain growth of the polymer, prevent over-polymerization, and also adjust the molecular weight and properties of the final polymer. Why it is called partial end-capping: This reaction is called partial end-capping because it does not completely block all isocyanate groups, but partially blocks the end groups of the polyurethane chain. Specifically: In this step, hydroxy acrylate monomers (such as HEA or HPA monomers) react with isocyanate groups (-NCO) to form hydroxyl-terminated polyurethanes. This partial end-capping means that not all isocyanate groups react with the hydroxy acrylate monomers, but some of the isocyanate groups remain unreacted, providing possible active sites for subsequent reactions. This partial end-capping strategy is usually to ensure that some parts of the polyurethane chain are sufficiently reactive to undergo further copolymerization or cross-linking reactions with subsequent other monomers (such as acrylate monomers). Introduction of acrylate functional groups: The introduction of acrylate groups on the polyurethane chain (through the reaction of hydroxy acrylate monomers) is to make the final waterborne polyurethane-acrylate adhesive have cross-linking and better adhesive properties. Acrylate groups are highly reactive groups and can participate in cross-linking in subsequent polymerization reactions to form more stable and strong bonds. Adjustment of molecular weight and performance: Through partial end-capping, the length of the final polyurethane molecular chain can be controlled, and its relative molecular weight can also be adjusted. Appropriate end-capping can control the solubility, mechanical properties and other physical and chemical properties of polyurethane. Avoid excessive cross-linking or polymerization: If complete end-capping is performed in this step, the degree of cross-linking of the polyurethane chain will be too high, thereby affecting the fluidity, stability and adhesion of the final emulsion. Therefore, partial end-capping can effectively avoid excessive polymerization while retaining moderate active sites. Enhancement of subsequent emulsion synthesis: The partially end-capped waterborne polyurethane can better react with acrylate monomers and participate in the subsequent emulsion polymerization reaction (polymerization reaction in step S2), thereby forming a waterborne polyurethane-acrylate adhesive with good adhesive properties. In this process, the final properties of the polyurethane-acrylate emulsion, such as bonding strength, thermal stability, flexibility, etc., all depend on the degree of this end-capping process and the control of subsequent reactions. Summary: Partial end-capping reaction is the process of introducing end-capping groups through the reaction of hydroxy acrylate monomers with isocyanate groups during the synthesis of waterborne polyurethane. Its purpose is to: 1) control the length and performance of the molecular chain; 2) retain a certain reactivity in the subsequent polymerization reaction to ensure that the final product has good bonding properties and cross-linking properties. This is a very important step that directly affects the performance of the final waterborne adhesive.

[0023] In step S1.5, the purpose of high-speed dispersion treatment in a cold water bath device is as follows: Improve the dispersion effect: When the water-based polyurethane prepolymer is mixed with deionized water, the viscosity of the system is relatively high. Through high-speed dispersion treatment, the polymer can be dispersed into fine particles to improve the uniformity and stability of the system. The cold water bath device can help to quickly cool the reaction mixture to avoid the reduction of the dispersion effect due to excessively high temperature, thereby achieving better dispersion and uniformity. Improve the dispersion effect. High-speed dispersion is not only for uniform mixing of the components, but also affects the size distribution of the final polymer particles. In the cold water bath device, the temperature of the cooling water is maintained at 5-15°C. This low temperature environment helps to control the growth and aggregation of the particles and avoids the aggregation or agglomeration of the particles due to excessively high temperatures. The cold water bath can effectively control the final size and dispersibility of the particles, which is very important for the performance of the water-based polyurethane adhesive, especially the fluidity and adhesion of the adhesive.

[0024] The purpose of slowly adding the aqueous solution of the post-chain extender is to avoid excessive heat accumulation caused by rapid reaction during the reaction. Too fast a reaction may lead to problems such as uneven degree of polymerization and unsatisfactory molecular weight distribution. Slowly adding the aqueous solution of the post-chain extender helps to ensure that the reactants react gradually and fully, so that the chain extension process proceeds evenly and the desired product properties are finally obtained.

[0025] The reason for controlling the amount of deionized water added is to ensure the formation of a water-based system. The preparation of water-based polyurethane adhesives relies on water as a solvent and dispersion medium. In the process of synthesizing water-based polyurethane prepolymers, it is necessary to add a certain amount of water to help dissolve and disperse the polyurethane components and promote the water-based nature of the system. The amount of deionized water added is relatively large, mainly to ensure that the reaction system can be effectively dispersed and emulsified to form a uniform water-based dispersion system. Too little water causes the reaction system to be too thick and unable to form a stable emulsion, affecting the final performance of the water-based adhesive. The amount of deionized water is set to 2-2.4 times the sum of other ingredients in order to provide an appropriate solvent environment throughout the reaction process, to ensure the smooth progress of the reaction, the uniformity of the system, the control of the reaction rate, and the quality stability of the final product.

[0026] The practice of adding the acrylate monomer mixture in two times is mainly to control the rate of polymerization, improve the efficiency of the reaction and optimize the final performance of the adhesive. The following are the principles and purposes of adding the acrylate monomer mixture in two times: 1. Control the polymerization reaction rate: Acrylate monomers (such as ethyl acrylate, isooctyl acrylate, etc.) copolymerize with waterborne polyurethane prepolymers during the polymerization process to form waterborne polyurethane-acrylate adhesives. Since the concentration of acrylate monomers is high at the beginning of the reaction, if all acrylate monomers are added at one time, the polymerization rate is too fast, resulting in the following problems: Too fast a reaction may cause premature cross-linking of the polymer molecular chain, forming an uneven polymer structure, affecting the performance of the final adhesive (such as bonding strength, flexibility, etc.). Too fast a reaction causes a sharp increase in polymer viscosity, affecting the fluidity of the reaction system, making the reaction incomplete or difficult to control. Therefore, adding acrylate monomers in two times can: slowly start the polymerization reaction to avoid too fast polymerization at the beginning of the reaction. Reduce the initial viscosity of the system to ensure that the system can react evenly and avoid local oversaturation or excessive viscosity. 2. Promote the formation of stable copolymers: When the acrylate monomer is first added, the concentration of acrylate is low, which helps control the interaction between the waterborne polyurethane prepolymer and the acrylate monomer, ensuring that the two can be evenly mixed and form a stable copolymer. At the beginning of the reaction, the low concentration of acrylate monomer will not excessively participate in the cross-linking reaction, which helps to avoid sudden changes in the properties of the adhesive. The second drop of acrylate monomer (adding the remaining 2 / 3 weight) is to promote the continuation of the polymerization reaction and ensure that the polymerization reaction can be completed under appropriate conditions to form a stable copolymer. Achieve the required acrylate content to ensure that the adhesive has appropriate mechanical properties (such as water resistance, bonding strength, etc.). 3. Avoid local over-polymerization and unevenness: If all acrylate monomers are added at once, some areas in the reaction system may experience local over-polymerization or cross-linking, resulting in uneven performance of the adhesive. Adding acrylate monomers in batches can avoid this situation and ensure the uniformity and consistency of the entire system by controlling the reaction. 4. Improve the activity of the chain initiator: In the polymerization reaction, the chain initiator (azobisisobutyronitrile) starts the activity of the polymerization reaction, and usually can be better activated and the polymerization reaction can be carried out when the concentration of the acrylate monomer is low. By adding the acrylate monomer in batches, sufficient monomers can be provided to the chain initiator at the appropriate time point to ensure that the effect of the initiator is maximized and the polymerization process proceeds smoothly. Therefore, the main purpose of adding the acrylate monomer mixture separately is to control the polymerization reaction rate, optimize the reaction conditions, avoid the adverse effects caused by too fast reaction, and ensure the stability and uniformity of the final performance of the adhesive. Through this method of adding in batches, the structure and properties of the adhesive can be effectively controlled, and its performance in practical applications can be improved.

[0027] Acetone is used as a viscosity regulator in the preparation method, and its main function is to reduce the viscosity of the reaction system, making the reaction mixture easier to handle and disperse. However, it is not desirable for acetone to exist in the product for a long time because it will affect the performance, stability and safety of the final product. The specific amount of acetone added is 10%-30% of the amount of the mixture after the partial end-capping reaction, preferably 15%-17%.

[0028] After the waterborne polyurethane-acrylate adhesive is prepared, a waterborne curing agent is selected during use. The specific model of the waterborne curing agent is DB-601 waterborne curing agent, which comes from Zhejiang Duobang New Materials Co., Ltd. The amount of the waterborne curing agent used is 1%-3% of the weight of the waterborne polyurethane-acrylate adhesive.

[0029] The principle of the present invention is as follows: a polyurethane prepolymer is synthesized by using aliphatic polycarbonate-polyether polyol, a hydrophilic chain extender and an isocyanate, and then partially end-capped with a hydroxy acrylate monomer. The neutralizing agent forms salt, the post-chain extender extends the chain at low temperature and the seed emulsion polymerizes to generate a core-shell structured waterborne polyurethane-acrylate emulsion. By selecting the type of polyurethane-acrylate monomer and optimizing the ratio of chain segments, the synthesized composite adhesive is pressure-sensitive and provides initial strength. In the later use process, the cross-linking of the curing agent improves the bonding strength and water-washing resistance of the composite fabric.

[0030] Compared with the prior art, the present invention has the following beneficial effects: First, by treating aliphatic polycarbonate-polyether polyol and other auxiliary materials, the polycondensation reaction of isocyanate is completed under temperature control conditions, and combined with hydroxy acrylate monomers through partial end-capping reaction to form a waterborne polyurethane prepolymer. In this process, the molecular structure of the polymer is precisely controlled by cooling, adjusting viscosity and adding post-chain extenders, so that the final product has good physical and chemical properties. Secondly, the waterborne polyurethane prepolymer is mixed with acrylate monomers, chain initiators, and deionized water and then subjected to polymerization reaction to form a waterborne polyurethane-acrylate adhesive emulsion. During the polymerization process, the remaining acrylate monomers are gradually added to ensure the adhesive properties of the adhesive and the stability of the emulsion. Finally, after the polymerization reaction is completed, the surface properties of the adhesive are further optimized by adding additives such as defoamers and leveling agents to ensure that it has good coating, leveling and defoaming properties, thereby improving the application effect of the final adhesive.

[0031] In summary, the present invention copolymerizes acrylate monomers onto the main chain of polyurethane by semi-continuous seed emulsion polymerization to form an emulsion with a core-shell structure, and the emulsion with this structure shows good stability and hydrolysis resistance; by selecting the type of polyurethane-acrylate monomers and optimizing the ratio of chain segments, the synthesized adhesive not only has pressure sensitivity and good initial bonding strength, but also can further improve the bonding and hydrolysis resistance through cross-linking reaction with a curing agent during subsequent use, wherein the soft monomer acrylate with a low glass transition temperature provides initial pressure sensitivity, and at the same time, a hydroxyl acrylate monomer is added to participate in a free radical polymerization reaction, and the hydroxyl group is branched with the amino group at the end of the polyurethane to increase the stability of the core-shell structure. DETAILED DESCRIPTION

[0032] The following are specific embodiments of the present invention, which further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0033] A method for preparing a waterborne polyurethane-acrylate adhesive for fabric lamination, the method comprising the following steps: S1 Preparation of waterborne polyurethane prepolymer: S1.1 Vacuum dehydration pretreatment: After the aliphatic polycarbonate-polyether polyol, nonionic polyol, hydrophilic chain extender and antioxidant 1010 are mixed evenly, vacuum dehydration is carried out at 120°C. After the dehydration operation is completed, a dehydrated mixture is obtained; S1.2 Isocyanate polycondensation reaction: The temperature of the dehydrated mixture is lowered to 55°C, isocyanate is added to the dehydrated mixture, mixed evenly, and reacted at a temperature of 110°C to obtain an isocyanate polycondensation reaction mixture; S1.3 Partial end-capping reaction: The temperature of the isocyanate polycondensation reaction mixture is cooled to 80°C, hydroxy acrylate monomer is added to the isocyanate polycondensation reaction mixture, mixed evenly, and reacted at a temperature of 80°C. After the reaction is completed, a partially end-capped reaction mixture is obtained; S1.4 Salt formation: Partial The temperature of the mixture after the end-blocking reaction is reduced to 55°C, a neutralizing agent and a viscosity adjusting agent are added to part of the mixture after the end-blocking reaction, and after being evenly mixed, a salt-forming reaction is carried out at a temperature of 55°C. After the reaction is completed, a mixture after the salt-forming reaction is obtained; S1.5 high-speed dispersion: after the temperature of the mixture after the salt-forming reaction is reduced to 25°C, the mixture after the salt-forming reaction is placed in a cold water bath device, and then deionized water is added, followed by high-speed dispersion treatment to obtain an initial dispersed mixture; the temperature of the cold water in the cold water bath device is 5°C; S1.6 dropwise addition of a post-chain extender: a post-chain extender aqueous solution is added dropwise to the initial dispersed mixture, and the dropwise addition time is T1. After the dropwise addition is completed, an initial target mixture is obtained; S1.7 post-treatment: the initial target mixture is subjected to a high-speed dispersion treatment. After the dispersion is completed, filtering operations and removal of the viscosity adjusting agent operations are performed in sequence to obtain a water-based polyurethane prepolymer; The aliphatic polycarbonate-polyether polyol is specifically PPCD, the nonionic polyol is specifically N120; the hydrophilic chain extender is DMPA, the isocyanate is specifically IPDI; the neutralizing agent is triethylamine; the aqueous solution of the post-chain extender is an aqueous solution of ethylenediamine, and the concentration is 50%; the hydroxy acrylate monomer is specifically HEA monomer; and the viscosity adjusting agent is selected as acetone; According to the weight ratio, aliphatic polycarbonate-polyether polyol: nonionic polyol: hydrophilic chain extender: isocyanate: antioxidant 1010: hydroxy acrylate monomer: neutralizer: post-chain extender is 65-80: 1-5: 2-5: 20-30: 0.1-0.5: 2-5: 1-3: 1-3; In step S1, the amount of deionized water used is 2-2.4 times the sum of the weight of the aliphatic polycarbonate-polyether polyol, the nonionic polyol, the hydrophilic chain extender, the isocyanate, the antioxidant 1010, the hydroxy acrylate monomer, the neutralizer and the post-chain extender; S2 Synthesis of waterborne polyurethane-acrylate emulsion: S2.1 Polymerization reaction: Add waterborne polyurethane prepolymer, 1 / 3 weight of acrylate monomer mixture, chain initiator and deionized water into a constant temperature reaction device, mix well, start the constant temperature reaction device, and set the working temperature of the constant temperature reaction device to 85°C; after reaction time T2, add 2 / 3 weight of acrylate monomer mixture by dropwise addition, and the dropwise addition time is T3; after the dropwise addition is completed, continue the heat preservation reaction, and the reaction time is T4. After the reaction is completed, obtain the polymerized reactant, S2.2 Cooling and adding auxiliary agents: Cool the temperature of the mixture after the polymerization reaction to 36°C, add defoaming agent and leveling agent, and stir. After stirring until uniform, obtain a waterborne polyurethane-acrylate adhesive; The acrylate monomer mixture includes ethyl acrylate, isooctyl acrylate, n-butyl acrylate and hydroxy acrylate, the chain initiator is azobisisobutyronitrile; the leveling agent is specifically Tego410 leveling agent; and the defoaming agent is specifically BYK-024 defoaming agent.

[0034] According to the weight ratio, the waterborne polyurethane prepolymer: ethyl acrylate: isooctyl acrylate: n-butyl acrylate: hydroxy acrylate: chain initiator: defoamer: leveling agent: deionized water is 100:10-15:1-3:3-6:1-3:0.05-1:0.05-1:0.05-1:35-50.

[0035] In step S1.1, the moisture content in the dehydrated mixture is less than 300 ppm.

[0036] In step S1.2, the isocyanate polycondensation reaction time is 2 hours; the partial blocking reaction time is 30 minutes; the salt formation reaction time is 30 minutes, T1 is 50 minutes; T2 is 60 minutes; T3 is 30 minutes, and T4 is 120 minutes. These times are sufficient to ensure the completion of the reaction.

[0037] In step S1.5 and step S1.7, the stirring speed of the high-speed dispersion treatment is 1000-15000 r / min; In step S1.7, in the filtering operation, a 200-mesh filter is used; In the process of removing the viscosity adjusting agent, acetone is removed by vacuum distillation.

[0038] Waterborne polyurethane-acrylate adhesive products 1, 2 and comparative products were prepared according to the above method. After preparation, a waterborne curing agent was selected during use. The specific model of the waterborne curing agent was DB-601 waterborne curing agent from Zhejiang Duobang New Materials Co., Ltd. The amount of the waterborne curing agent used was 2% of the product weight. The specific weight parameters in the preparation process and the product performance test parameters are shown in Table 1: Table 1 Viscosity test standard: Refer to ASTM D1084-16 (2021) rotational viscosity test method.

[0039] Solid content test standard: refer to the test method for non-volatile matter in GB / T11175-2021 Test method for synthetic resin emulsion.

[0040] Emulsion stability test method: Centrifuge at 3000r / min for 15min in a centrifuge to observe whether precipitation and emulsion stratification occur.

[0041] Test method for water absorption: refer to GB / T1034-2008 Test method for water absorption of plastics.

[0042] Test standards for tensile strength and elongation at break: refer to GB / T 528-2009 for testing.

[0043] Ring tack test standard: refer to GB / T31125-2014 Adhesive tape initial tack test method ring method.

[0044] Peel strength test standard: GB / T 2791-1995 test standard for peel strength of flexible material to flexible material.

[0045] Test standard for water washing conditions: refer to the water washing test method in HG / T 3697-2016.

[0046] The performance analysis is as follows: Viscosity: Viscosity is an important indicator for evaluating the fluidity and workability of adhesives. The viscosities of Product 1 and Product 2 are 200mPa·s and 160mPa·s respectively, which are much higher than the 80 mPa·s of the comparative product. Higher viscosity helps provide better control during coating and bonding, thereby reducing dripping and uneven coating.

[0047] Emulsion stability: Both Product 1 and Product 2 showed good emulsion stability with no precipitation or stratification. This is a particularly important property for water-based systems, as any precipitation or stratification may lead to inconsistencies in application and affect the quality of the final product.

[0048] Water absorption rate: The water absorption rate of waterborne polyurethane is an indicator for evaluating its waterproof performance. The water absorption rates of product 1 and product 2 are 4.5% and 6.0%, which are significantly better than the 12.6% of the comparative product. This shows that the modified waterborne polyurethane adhesive has a better ability to resist water intrusion.

[0049] Tensile strength and elongation at break: The tensile strength of product 1 and product 2 are 32 MPa and 29 MPa, respectively, and the elongation at break are 800% and 880%, respectively, showing excellent flexibility and tensile properties.

[0050] Initial tack and peel strength: Initial tack and peel strength are important indicators for evaluating the immediate and long-term bonding ability of adhesives. Products 1 and 2 have good initial tack and peel strength, especially after washing, they do not show warping or delamination, indicating that they have good water-washing resistance.

[0051] From the performance comparison, it can be seen that the comparison product without acrylate modification has a higher water absorption rate and poor initial adhesion, especially is not resistant to water washing, while the modified water-based polyurethane-acrylate adhesive products 1 and 2 have better comprehensive performance.

[0052] The specific embodiments described herein are merely examples of the spirit of the present invention. A person skilled in the art of the present invention may make various modifications or supplements to the specific embodiments described or replace them in a similar manner, but will not deviate from the spirit of the present invention or exceed the defined scope. Although the present invention is described and described in detail in the foregoing description, such descriptions and descriptions are considered to be illustrative or exemplary rather than restrictive. It should be understood that within the scope of the following claims, changes and modifications may be made by a person of ordinary skill. Specifically, the present invention encompasses additional embodiments having any combination of features from the above-mentioned different embodiments. With respect to the use of the expression "generally" or "substantially", this patent application should be understood to disclose that these features and values ​​are also fully satisfied, i.e., there is no aforementioned characterization as "generally" or "substantially".

Claims

1. A method for preparing a water-based polyurethane-acrylate adhesive for fabric lamination, characterized in that: The preparation method of waterborne polyurethane-acrylate adhesive comprises the following steps: S1 Preparation of waterborne polyurethane prepolymer: S1.1 Dehydration pretreatment: After uniformly mixing aliphatic polycarbonate-polyether polyol PPCD, nonionic polyol N120, hydrophilic chain extender and antioxidant, dehydration is performed to obtain a dehydrated mixture; S1.2 Isocyanate polycondensation reaction: After cooling the dehydrated mixture, isocyanate is added to the dehydrated mixture for polycondensation reaction to obtain an isocyanate polycondensation reaction mixture; S1.3 Partial end-capping reaction: After cooling the isocyanate polycondensation reaction mixture, hydroxy acrylate monomer is added to the isocyanate polycondensation reaction mixture for partial end-capping reaction to obtain a partially end-capping reaction mixture; S1.4 Salt formation : After cooling the partially blocked reaction mixture, a neutralizing agent and a viscosity adjusting agent are added to the partially blocked reaction mixture to carry out a salt-forming reaction to obtain a salt-forming reaction mixture; S1.5 high-speed dispersion: After cooling the salt-forming reaction mixture, the mixture is placed in a cold water bath, and then deionized water is added, followed by a high-speed dispersion treatment to obtain an initial dispersed mixture; S1.6 dropwise addition of a post-chain extender: an aqueous solution of a post-chain extender is added to the initial dispersed mixture to react to obtain an initial target mixture; S1.7 post-treatment: the initial target mixture is subjected to a high-speed dispersion treatment, and after the dispersion is completed, filtering operations and removing viscosity adjusting agents are performed in sequence to obtain a waterborne polyurethane prepolymer; S2 Synthesis of water-based polyurethane-acrylate emulsion: S2.1 Polymerization reaction: Mix the water-based polyurethane prepolymer, part of the acrylate monomer mixture, the chain initiator and deionized water evenly and then carry out a polymerization reaction; after the reaction is completed, add the remaining acrylate monomer mixture by dropwise addition, continue the polymerization reaction, and obtain a polymerization reaction mixture; S2.2 Addition of auxiliary agents: After cooling the mixture after the polymerization reaction, add a defoaming agent and a leveling agent, stir until uniform, and obtain a water-based polyurethane-acrylate adhesive.

2. The method for preparing the water-based polyurethane-acrylate adhesive for fabric lamination according to claim 1, characterized in that: In step S1, the antioxidant is antioxidant 1010; and the viscosity adjusting agent is acetone.

3. The method for preparing the water-based polyurethane-acrylate adhesive for fabric lamination according to claim 2, characterized in that: In step S1, according to the weight ratio, aliphatic polycarbonate-polyether polyol PPCD: nonionic polyol N120: hydrophilic chain extender: isocyanate: antioxidant 1010: hydroxy acrylate monomer: neutralizer: post-chain extender is 65-80:1-5:2-5:20-30:0.1-0.5:2-5:1-3:1-3; the amount of deionized water used is 2-2.4 times the sum of the weight of aliphatic polycarbonate-polyether polyol PPCD, nonionic polyol N120, hydrophilic chain extender, isocyanate, antioxidant 1010, hydroxy acrylate monomer, neutralizer and post-chain extender.

4. The method for preparing the water-based polyurethane-acrylate adhesive for fabric lamination according to claim 2, characterized in that: In the process of removing the viscosity adjusting agent, acetone is removed by vacuum distillation.

5. The method for preparing the water-based polyurethane-acrylate adhesive for fabric lamination according to claim 1, characterized in that: In the aqueous solution of the post-chain extender, the concentration of ethylenediamine is 50%.

6. The method for preparing the water-based polyurethane-acrylate adhesive for fabric lamination according to claim 1, characterized in that: In step S2.1, the weight ratio of waterborne polyurethane prepolymer: ethyl acrylate: isooctyl acrylate: n-butyl acrylate: hydroxy acrylate: chain initiator: deionized water is 100:10-15:1-3:3-6:1-3:0.05-1:35-50.

7. The method for preparing the water-based polyurethane-acrylate adhesive for fabric lamination according to claim 1, characterized in that: In step S2.1, the weight ratio of the partial acrylate monomer mixture to the remaining acrylate monomer mixture is 1:

2.

8. The method for preparing the water-based polyurethane-acrylate adhesive for fabric lamination according to claim 1, characterized in that: In step S1.1, the dehydration operation is performed under vacuum conditions, the temperature of the dehydration operation is 110-120°C, and the moisture content in the dehydrated mixture is less than 300ppm.

9. The method for preparing the water-based polyurethane-acrylate adhesive for fabric lamination according to claim 1, characterized in that: In step S1.2, the target temperature of the cooling operation is lower than 60°C, and the condensation reaction temperature is 100-110°C; in step S1.3, the target temperature of the cooling operation is 80°C, and the partial end-capping reaction temperature is 80°C; in step S1.4, the target temperature of the cooling operation is 55-60°C, and the salt-forming reaction temperature is 55-60°C; in step S1.5, the target temperature of the cooling operation is not higher than 30°C, and the temperature of the cold water in the cold water bath device is 5-15°C; in step S2.1, the polymerization reaction temperature is 80-85°C; in step S2.2, the target temperature of the cooling operation is lower than 40°C.

10. The method for preparing the water-based polyurethane-acrylate adhesive for fabric lamination according to claim 1, characterized in that: In step S2.2, the leveling agent is specifically one of Tego410 leveling agent, Tego425 leveling agent and Runhe T1008 leveling agent; the defoaming agent is specifically one of 810S defoaming agent and BYK-024 defoaming agent.

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