Emulsion type large-particle-size acrylate pressure-sensitive adhesive and preparation method thereof

Abstract

The invention relates to the field of emulsion type pressure-sensitive adhesives, in particular to an emulsion type large-particle-size acrylate pressure-sensitive adhesive and a preparation method thereof. The problems of large reaction heat release, low mechanical property index and low solid content of the product in the common technology are solved. Comprising an acrylate soft monomer, an acrylate hard monomer, a functional monomer, an emulsifier, an initiator, deionized water, a pH regulator, an oxidizing agent and a reducing agent. By introducing the special emulsifier and changing the suspension polymerization process, the process is greatly simplified, the production equipment is simple and convenient, the production efficiency is improved, the production cost is reduced, the cohesion strength and the adhesive force performance are improved by introducing the functional monomer, and meanwhile, the product performance is also improved.

Description

Technical Field

[0001] The invention relates to the field of emulsion type pressure-sensitive adhesives, and in particular to an emulsion type large-particle size acrylic pressure-sensitive adhesive and a preparation method thereof. Background Art

[0002] Pressure sensitive adhesive is a pressure sensitive, sticky and reusable adhesive. It can be immediately adhered to the surface of an object under slight pressure without additional heating or solvent treatment. Pressure sensitive adhesive usually has both the viscous properties of liquid and the elastic properties of solid. This viscoelastic body can withstand the influence factors and properties of both the contact process and the destruction process of bonding.

[0003] Emulsion-based acrylic pressure-sensitive adhesive is environmentally friendly and pollution-free, has a wide range of raw materials, is easy to stick on, easy to peel off, can be peeled off without damage, and the adhesive layer will not dry up for a long time.

[0004] At present, the pressure-sensitive adhesive for post-it notes on the market is mainly emulsion-type acrylate, which is prepared by suspension polymerization. However, due to the limitations of the polymerization process, there are corresponding problems such as high requirements for reaction equipment, large reaction heat release, high process risks, low product solid content, and high cost. In addition, the emulsion-type acrylate pressure-sensitive adhesive for post-it notes generally has poor transferability, is prone to residual glue, has low mechanical performance indicators, and is easy to fall off.

[0005] Therefore, it is urgent to propose an emulsion-type large-particle acrylic pressure-sensitive adhesive and a preparation method to solve the above technical problems. Summary of the invention

[0006] In order to solve the problems of large reaction heat release, low mechanical property index and low solid content of the product formed by the conventional technology, the present invention provides a brief summary of the present invention below to provide a basic understanding of certain aspects of the present invention. It should be understood that this summary is not an exhaustive summary of the present invention. It is not intended to determine the key or important parts of the present invention, nor is it intended to limit the scope of the present invention.

[0007] The technical solution of the present invention:

[0008] . An emulsion type large particle size acrylic pressure sensitive adhesive, characterized in that: the emulsion type large particle size acrylic pressure sensitive adhesive is composed of acrylic soft monomer, acrylic hard monomer, functional monomer, emulsifier, initiator, deionized water, pH adjuster, oxidant and reducing agent;

[0009] The mass fraction of the acrylic soft monomer is 85-95 parts, the mass fraction of the acrylic hard monomer is 5-10 parts, the mass fraction of the functional monomer is 5-10 parts, the mass fraction of the emulsifier is 1-5 parts, the mass fraction of the initiator is 0.4-0.8 parts, the mass fraction of deionized water is 120-180 parts, the mass fraction of the pH adjuster is 0.1-0.5 parts, the mass fraction of the oxidant is 0.1-0.3 parts, and the mass fraction of the reducing agent is 0.1-0.3 parts.

[0010] Preferably, the acrylic acid ester soft monomer is one or more of butyl acrylate and isooctyl acrylate.

[0011] Preferably, the acrylic acid ester hard monomer is one or more of styrene and methyl methacrylate.

[0012] Preferably, the functional monomer is one or more of hydroxyethyl acrylate and glycidyl methacrylate.

[0013] Preferably, the emulsifier is one or more of octadecylamine polyoxyethylene ether diquaternary ammonium salt, nonylphenol polyoxyethylene ether, and polyvinyl alcohol.

[0014] Preferably, the initiator is ammonium persulfate, the solvent is deionized water, the oxidant is tert-butyl hydroperoxide, and the reducing agent is sodium formaldehyde sulfoxylate.

[0015] Preferably, the pH regulator is one or more of ammonium bicarbonate and sodium bicarbonate.

[0016] The present invention has the following beneficial effects:

[0017] The present invention introduces a special emulsifier to change the suspension polymerization process, thereby greatly simplifying the process, making the production equipment simple, improving the production efficiency, and reducing the production cost;

[0018] The present invention increases the cohesive strength and adhesion performance by introducing functional monomers, and the product performance is also improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the particle size analysis test diagram of Example 1;

[0020] Figure 2 This is the particle size analysis test diagram of Example 2;

[0021] Figure 3 This is the particle size analysis test diagram of Example 3;

[0022] Figure 4 This is the particle size analysis test diagram of Example 4;

[0023] Figure 5This is the particle size analysis test diagram of Example 5;

[0024] Figure 6 This is the particle size analysis test chart of Example 6. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is described below by specific embodiments. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0026] Specific implementation method 1: This implementation method is an emulsion type large particle size acrylic pressure sensitive adhesive, the emulsion type large particle size acrylic pressure sensitive adhesive is composed of acrylic soft monomer, acrylic hard monomer, functional monomer, emulsifier, initiator, deionized water, pH adjuster, oxidant and reducing agent;

[0027] The mass fraction of the acrylic soft monomer is 85-95 parts, the mass fraction of the acrylic hard monomer is 5-10 parts, the mass fraction of the functional monomer is 5-10 parts, the mass fraction of the emulsifier is 1-5 parts, the mass fraction of the initiator is 0.4-0.8 parts, the mass fraction of deionized water is 120-180 parts, the mass fraction of the pH adjuster is 0.1-0.5 parts, the mass fraction of the oxidant is 0.1-0.3 parts, and the mass fraction of the reducing agent is 0.1-0.3 parts. The emulsion type large-particle acrylic pressure-sensitive adhesive provides multiple advantages for its wide application, especially in the fields requiring bonding performance and diverse use environments, and shows strong competitiveness.

[0028] Specific implementation method 2: In this implementation method, an emulsion-type large-particle acrylic pressure-sensitive adhesive is used. The acrylic soft monomer is one or more of butyl acrylate and isooctyl acrylate. Through its unique molecular structure and properties, it plays a vital role in acrylic pressure-sensitive adhesives. They can not only improve the low-temperature adhesion performance of the glue, but also enhance the flexibility, weather resistance and UV resistance of the glue. Through reasonable selection and ratio, the overall performance of the glue can be optimized according to actual needs.

[0029] Specific implementation method three: This implementation method is an emulsion type large particle size acrylic pressure sensitive adhesive, the acrylic hard monomer is one or more of styrene and methyl methacrylate, this emulsion type large particle size acrylic pressure sensitive adhesive, using hard monomers such as styrene and methyl methacrylate, can provide excellent mechanical properties, weather resistance and transparency. Through precise process control, it can achieve ideal effects in various bonding applications, especially in situations requiring high heat resistance, strong adhesion and good transparency.

[0030] Specific implementation method 4: In this implementation method, an emulsion-type large-particle acrylic pressure-sensitive adhesive, the functional monomer is one or more of hydroxyethyl acrylate and glycidyl methacrylate. This emulsion-type large-particle acrylic pressure-sensitive adhesive uses hydroxyethyl acrylate and glycidyl methacrylate as functional monomers, which can significantly improve the initial viscosity, heat resistance, water resistance, UV resistance and mechanical properties of the adhesive. By adjusting the proportion of these functional monomers, it can be used according to different application requirements.

[0031] Specific implementation method five: This implementation method is an emulsion-type large-particle acrylic pressure-sensitive adhesive, and the emulsifier is one or more of octadecylamine polyoxyethylene ether diquaternary ammonium salt, nonylphenol polyoxyethylene ether, and polyvinyl alcohol. This combination can simultaneously obtain the advantages of anionic and nonionic emulsifiers, enhance the stability of the emulsion, and improve the initial viscosity and adhesion of the adhesive. It is suitable for applications that require high adhesion and emulsion stability.

[0032] Specific embodiment six: This embodiment is an emulsion type large-particle acrylic pressure-sensitive adhesive, the initiator is ammonium persulfate, the solvent is deionized water, the oxidant is tert-butyl hydroperoxide, and the reducing agent is sodium formaldehyde sulfoxylate. The present invention uses ammonium persulfate as an initiator, deionized water as a solvent, tert-butyl hydroperoxide as an oxidant and sodium formaldehyde sulfoxylate as a reducing agent, which act synergistically in the reaction, can effectively control the polymerization process, and form large-particle polymer particles with good adhesion and environmental friendliness.

[0033] Specific implementation seven: In this implementation, an emulsion-type large-particle acrylic pressure-sensitive adhesive, the pH regulator is one or more of ammonium bicarbonate and sodium bicarbonate. Ammonium bicarbonate and sodium bicarbonate are used as pH regulators. In the preparation of the emulsion-type large-particle acrylic pressure-sensitive adhesive, the pH of the reaction system can be effectively adjusted to ensure the smooth progress of the polymerization process and the stability and performance of the final product. The two can be used alone or in synergy, and which one to use depends on the specific needs of the reaction system and the required pH range.

[0034] Specific embodiment 8: A method for preparing an emulsion-type large-particle acrylic pressure-sensitive adhesive in this embodiment comprises the following steps:

[0035] Step 1: Add 0.4-0.8 parts of initiator to 5-10 parts of deionized water and stir to obtain an initiator solution;

[0036] Step 2: Add 0.1-1 parts of emulsifier, 85-95 parts of acrylate soft monomer, 5-10 parts of acrylate hard monomer and 5-10 parts of functional monomer into 40-60 parts of deionized water, disperse at high speed for 10-15 minutes, then add 60% initiator solution, continue stirring to prepare a mixed pre-emulsion;

[0037] Step 3: Add 0.1-0.3 parts of oxidant to 1-5 parts of deionized water, and stir to obtain an oxidant solution; add 0.1-0.3 parts of reductant to 1-5 parts of deionized water, and stir to obtain a reductant solution;

[0038] Step 4: 80-120 parts of deionized water, 0.9-4 parts of emulsifier and 0.1-0.5 parts of pH regulator are mixed and stirred evenly in a reaction kettle, heated to 80° C., and then the remaining initiator solution is added;

[0039] Step 5: Raise the temperature of the reactor to 82°C, start dripping the mixed pre-emulsion, keep the reaction temperature at 81-85°C, and add for 3.5-4.5h. After the addition is completed, keep warm for 1h, during which the motor speed is 240-500r / min;

[0040] Step 6: After the heat preservation is completed, the temperature is lowered to 70°C, and the oxidant solution is added. After 5-10 minutes, the reducing agent solution is added, and stirring and heat preservation are continued. The temperature is kept for 30 minutes, and the temperature is lowered to below 50°C. The material is filtered to obtain an emulsion type large particle size acrylic pressure-sensitive adhesive.

[0041] The above method realizes the preparation of emulsion type large particle size acrylic pressure sensitive adhesive by strictly controlling the reaction conditions and adopting the redox initiation system. The adhesive has good adhesion, weather resistance and shear resistance, and is suitable for various adhesive applications, such as labels, packaging, film materials, etc. By accurately controlling the reaction conditions, raw material ratios and process steps, an emulsion type pressure sensitive adhesive with uniform particle size and excellent performance can be obtained.

[0042] The emulsion particle size range of the emulsion-type large-particle acrylic pressure-sensitive adhesive prepared above is 1-50 μm. The large-particle emulsion can improve the adhesion of the adhesive because larger particles can provide stronger contact points on the contact surface. Under high temperature or harsh environment, large-particle emulsion pressure-sensitive adhesives usually show better stability and weather resistance. Due to the large particle size, the large-particle emulsion pressure-sensitive adhesive has lower hydrolysis, which helps to enhance the stability of the adhesive in a humid environment.

[0043] Example 1

[0044] A method for preparing an emulsion-type large-particle acrylic pressure-sensitive adhesive comprises the following steps:

[0045] Step 1: Add 0.5 g of ammonium persulfate to 6 g of deionized water and stir to obtain an initiator solution;

[0046] Step 2: Add 0.45g of octadecylamine polyoxyethylene ether diquaternary ammonium salt, 85g of isooctyl acrylate, 6g of styrene, 3g of hydroxyethyl acrylate and 6g of glycidyl methacrylate into 45g of deionized water, disperse at high speed for 10 minutes, and then add 3.9g of initiator solution to prepare a mixed pre-emulsion;

[0047] Step 3: Add 0.25 g of tert-butyl hydroperoxide to 3 g of deionized water, and stir to obtain an oxidant solution; add 0.25 g of sodium formaldehyde sulfoxylate to 3 g of deionized water, and stir to obtain a reducing agent solution;

[0048] Step 4: 100 g of deionized water, 0.8 g of octadecylamine polyoxyethylene ether diquaternary ammonium salt, 0.4 g of polyvinyl alcohol and 0.25 g of ammonium bicarbonate were mixed and stirred in a reaction kettle, heated to 80° C., and then the remaining 2.6 g of initiator solution was added;

[0049] Step 5: Raise the temperature of the reactor to 82°C, and begin to gradually drop the mixed pre-emulsion, keep the reaction temperature at 83±2°C, drop for 4 hours, and keep at 85°C for 1 hour after the drop is finished. During the drop period, the motor speed increases from 240r / min to 400r / min by 40r / min per hour;

[0050] Step 6: After the heat preservation is completed, the temperature is lowered to 70°C, and the oxidant solution is added. After 5 minutes, the reducing agent solution is added, and stirring and heat preservation are continued for 30 minutes. Then the temperature is lowered to 50°C, and the material is filtered to obtain an emulsion type large-particle acrylic pressure-sensitive adhesive.

[0051] like Figure 1 The particle size analysis test results shown in the figure show that the particle size of the microspheres is 21.342 um using the d(0.5) data.

[0052] Example 2

[0053] A method for preparing an emulsion-type large-particle acrylic pressure-sensitive adhesive comprises the following steps:

[0054] Step 1: Add 0.7 g of ammonium persulfate to 6 g of deionized water and stir to obtain an initiator solution;

[0055] Step 2: Add 0.3 g of octadecylamine polyoxyethylene ether diquaternary ammonium salt, 0.1 g of nonylphenol polyoxyethylene ether, 70 g of isooctyl acrylate, 16 g of butyl acrylate, 8 g of styrene and 6 g of hydroxyethyl acrylate into 50 g of deionized water, disperse at high speed for 10 minutes, and then add 4.02 g of initiator solution to prepare a mixed pre-emulsion;

[0056] Step 3: Add 0.25 g of tert-butyl hydroperoxide to 5 g of deionized water, and stir to obtain an oxidant solution; add 0.25 g of sodium formaldehyde sulfoxylate to 5 g of deionized water, and stir to obtain a reducing agent solution;

[0057] Step 4: 100 g of deionized water, 1.0 g of octadecylamine polyoxyethylene ether diquaternary ammonium salt, 0.8 g of polyvinyl alcohol and 0.25 g of ammonium bicarbonate were mixed and stirred in a reaction kettle, heated to 80° C., and then the remaining 2.68 g of initiator solution was added;

[0058] Step 5: Raise the temperature of the reactor to 82°C, and begin to gradually drop the mixed pre-emulsion, keep the reaction temperature at 83±2°C, drop for 4 hours, and keep at 85°C for 1 hour after the drop is finished. During the drop period, the motor speed increases from 240r / min to 400r / min by 40r / min per hour;

[0059] Step 6: After the heat preservation is completed, the temperature is lowered to 70°C, and the oxidant solution is added. After 5 minutes, the reducing agent solution is added, and stirring and heat preservation are continued for 30 minutes. Then the temperature is lowered to 50°C, and the material is filtered to obtain an emulsion type large-particle acrylic pressure-sensitive adhesive.

[0060] like Figure 2 The particle size analysis test results shown in the figure show that the particle size of the microspheres is 5.977um as obtained by taking the d(0.5) data.

[0061] Example 3

[0062] A method for preparing an emulsion-type large-particle acrylic pressure-sensitive adhesive comprises the following steps:

[0063] Step 1: Add 0.4 g of ammonium persulfate to 6 g of deionized water and stir to obtain an initiator solution;

[0064] Step 2: Add 0.5 g of octadecylamine polyoxyethylene ether diquaternary ammonium salt, 80 g of isooctyl acrylate, 10 g of butyl acrylate, 7 g of methyl methacrylate, 4 g of hydroxyethyl acrylate and 3 g of glycidyl methacrylate into 40 g of deionized water, disperse at high speed for 10 minutes, and then add 3.84 g of initiator solution to prepare a mixed pre-emulsion;

[0065] Step 3: Add 0.25 g of tert-butyl hydroperoxide to 5 g of deionized water, and stir to obtain an oxidant solution; add 0.25 g of sodium formaldehyde sulfoxylate to 5 g of deionized water, and stir to obtain a reducing agent solution;

[0066] Step 4: 110 g of deionized water, 0.5 g of octadecylamine polyoxyethylene ether diquaternary ammonium salt, 1.2 g of polyvinyl alcohol, 0.5 g of nonylphenol polyoxyethylene ether and 0.25 g of sodium bicarbonate were mixed and stirred in a reaction kettle, heated to 80° C., and then the remaining 2.56 g of initiator solution was added;

[0067] Step 5: Raise the temperature of the reactor to 82°C, start to gradually drop the mixed pre-emulsion, keep the reaction temperature at 83±2°C, drop for 4h, and keep at 85°C for 1h after the drop is finished. During the drop, the motor speed is increased from 240r / min to 440r / min by 50r / min per hour;

[0068] Step 6: After the heat preservation is completed, the temperature is lowered to 70°C, and the oxidant solution is added. After 5 minutes, the reducing agent solution is added, and stirring and heat preservation are continued for 30 minutes. Then the temperature is lowered to 50°C, and the material is filtered to obtain an emulsion type large-particle acrylic pressure-sensitive adhesive.

[0069] like Figure 3 The particle size analysis test results are shown as follows: Taking the d(0.5) data, the microsphere particle size is 11.423um.

[0070] Example 4

[0071] A method for preparing an emulsion-type large-particle acrylic pressure-sensitive adhesive comprises the following steps:

[0072] Step 1: Add 0.8 g of ammonium persulfate to 6 g of deionized water and stir to obtain an initiator solution;

[0073] Step 2: add 0.5g of octadecylamine polyoxyethylene ether diquaternary ammonium salt, 0.4g of nonylphenol polyoxyethylene ether, 75g of isooctyl acrylate, 18g of butyl acrylate, 10g of methyl methacrylate, 4g of hydroxyethyl acrylate and 5g of glycidyl methacrylate into 60g of deionized water, disperse at high speed for 10 minutes, and then add 4.08g of initiator solution to prepare a mixed pre-emulsion;

[0074] Step 3: Add 0.25 g of tert-butyl hydroperoxide to 5 g of deionized water, and stir to obtain an oxidant solution; add 0.25 g of sodium formaldehyde sulfoxylate to 5 g of deionized water, and stir to obtain a reducing agent solution;

[0075] Step 4: 120 g of deionized water, 1.5 g of octadecylamine polyoxyethylene ether diquaternary ammonium salt, 0.3 g of polyvinyl alcohol and 0.25 g of sodium bicarbonate were mixed and stirred evenly in a reaction kettle, heated to 80° C., and then the remaining 2.72 g of initiator solution was added;

[0076] Step 5: Raise the temperature of the reactor to 82°C, start dripping the mixed pre-emulsion, keep the reaction temperature at 83±2°C, drip for 4h, and keep at 85°C for 1h after the dripping is finished. During the dripping period, the motor speed is increased from 240r / min to 440r / min by 50r / min per hour;

[0077] Step 6: After the heat preservation is completed, the temperature is lowered to 70°C, and the oxidant solution is added. After 5 minutes, the reducing agent solution is added, and stirring and heat preservation are continued for 30 minutes. Then the temperature is lowered to 50°C, and the material is filtered to obtain an emulsion type large-particle acrylic pressure-sensitive adhesive.

[0078] like Figure 4 The particle size analysis test results are shown as follows: Taking the d(0.5) data, the microsphere particle size is 44.33um.

[0079] Example 5

[0080] A method for preparing an emulsion-type large-particle acrylic pressure-sensitive adhesive comprises the following steps:

[0081] Step 1: Add 0.6 g of ammonium persulfate to 6 g of deionized water and stir to obtain an initiator solution;

[0082] Step 2: add 0.4g of octadecylamine polyoxyethylene ether diquaternary ammonium salt, 0.2g of nonylphenol polyoxyethylene ether, 75g of isooctyl acrylate, 10g of butyl acrylate, 8g of styrene, 2g of hydroxyethyl acrylate and 4g of glycidyl methacrylate into 45g of deionized water, disperse at high speed for 10 minutes, and then add 3.96g of initiator solution to prepare a mixed pre-emulsion;

[0083] Step 3: Add 0.25 g of tert-butyl hydroperoxide to 5 g of deionized water, and stir to obtain an oxidant solution; add 0.25 g of sodium formaldehyde sulfoxylate to 5 g of deionized water, and stir to obtain a reducing agent solution;

[0084] Step 4: 90g of deionized water, 0.6g of octadecylamine polyoxyethylene ether diquaternary ammonium salt, 1.5g of polyvinyl alcohol, 1.2g of nonylphenol polyoxyethylene ether and 0.25g of ammonium bicarbonate are mixed and stirred evenly in a reaction kettle, heated to 80°C, and then the remaining 2.64g of initiator solution is added;

[0085] Step 5: Raise the temperature of the reactor to 82°C, and begin to gradually drop the mixed pre-emulsion, keep the reaction temperature at 83±2°C, drop for 4 hours, and keep at 85°C for 1 hour after the drop is finished. During this period, the motor speed increases from 240r / min to 440r / min by 50r / min per hour during the drop period;

[0086] Step 6: After the heat preservation is finished, the temperature is lowered to 70°C, and the oxidant solution is added. After 5 minutes, the reducing agent solution is added, and the stirring and heat preservation are continued for 30 minutes. Then the temperature is lowered to 50°C, and the material is filtered to obtain an emulsion type large particle size acrylic pressure-sensitive adhesive;

[0087] like Figure 5 The particle size analysis test results are shown below. Taking the d(0.5) data, the microsphere particle size is 31.405um.

[0088] Example 6

[0089] A method for preparing an emulsion-type large-particle acrylic pressure-sensitive adhesive comprises the following steps:

[0090] Step 1: Add 0.5 g of ammonium persulfate to 6 g of deionized water and stir to obtain an initiator solution;

[0091] Step 2: Add 0.6 g of octadecylamine polyoxyethylene ether diquaternary ammonium salt, 80 g of isooctyl acrylate, 15 g of butyl acrylate, 5 g of styrene and 8 g of glycidyl methacrylate into 50 g of deionized water, disperse at high speed for 10 minutes, and then add 3.9 g of initiator solution to prepare a mixed pre-emulsion;

[0092] Step 3: Add 0.25 g of tert-butyl hydroperoxide to 5 g of deionized water, and stir to obtain an oxidant solution; add 0.25 g of sodium formaldehyde sulfoxylate to 5 g of deionized water, and stir to obtain a reducing agent solution;

[0093] Step 4: 110 g of deionized water, 1.0 g of octadecylamine polyoxyethylene ether diquaternary ammonium salt, 0.3 g of polyvinyl alcohol, 1.2 g of nonylphenol polyoxyethylene ether and 0.25 g of ammonium bicarbonate were mixed and stirred evenly in a reaction kettle, heated to 80° C., and then the remaining 2.6 g of initiator solution was added;

[0094] Step 5: The temperature rises to 82°C, and the mixed pre-emulsion is gradually added dropwise. The reaction temperature is maintained at 83±2°C for 4 hours. After the addition is completed, the temperature is kept at 85°C for 1 hour. During the addition, the motor speed is increased by 40r / min per hour from 240r / min to 400r / min.

[0095] Step 6: After the heat preservation is completed, the temperature is lowered to 70°C, and the oxidant solution is added. After 5 minutes, the reducing agent solution is added, and stirring and heat preservation are continued for 30 minutes. Then the temperature is lowered to 50°C, and the material is filtered to obtain an emulsion type large-particle acrylic pressure-sensitive adhesive.

[0096] like Figure 6 The particle size analysis test results shown are as follows: taking d(0.5) data, the microsphere particle size is 1.003um.

[0097] The performance of the emulsion-type large-particle acrylic pressure-sensitive adhesive of Example 1-6 was tested. The test basis and test results are shown in Table 1 below:

[0098] Table 1

[0099]

[0100] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions described in the above embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0101] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be arranged and combined, and those skilled in the art can exhaust all possibilities based on the mathematical knowledge of arrangement and combination. Therefore, the present invention will no longer describe the technical solutions after arrangement and combination one by one, but it should be understood that the technical solutions after arrangement and combination have been disclosed by the present invention.

[0102] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An emulsion-type large-particle acrylic pressure-sensitive adhesive, characterized in that: The emulsion type large-particle acrylic pressure-sensitive adhesive is composed of acrylic soft monomer, acrylic hard monomer, functional monomer, emulsifier, initiator, deionized water, pH regulator, oxidant and reducing agent; The mass fraction of the acrylic soft monomer is 85-95 parts, the mass fraction of the acrylic hard monomer is 5-10 parts, the mass fraction of the functional monomer is 5-10 parts, the mass fraction of the emulsifier is 1-5 parts, the mass fraction of the initiator is 0.4-0.8 parts, the mass fraction of deionized water is 120-180 parts, the mass fraction of the pH adjuster is 0.1-0.5 parts, the mass fraction of the oxidant is 0.1-0.3 parts, and the mass fraction of the reducing agent is 0.1-0.3 parts.

2. The emulsion-type large-particle acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The acrylic acid ester soft monomer is one or more of butyl acrylate and isooctyl acrylate.

3. The emulsion-type large-particle acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The acrylic acid ester hard monomer is one or more of styrene and methyl methacrylate.

4. The emulsion-type large-particle acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The functional monomer is one or more of hydroxyethyl acrylate and glycidyl methacrylate.

5. The emulsion-type large-particle acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The emulsifier is one or more of octadecylamine polyoxyethylene ether diquaternary ammonium salt, nonylphenol polyoxyethylene ether, and polyvinyl alcohol.

6. The emulsion-type large-particle acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The initiator is ammonium persulfate, the solvent is deionized water, the oxidant is tert-butyl hydroperoxide, and the reducing agent is sodium formaldehyde sulfoxylate.

7. The emulsion-type large-particle acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The pH regulator is one or more of ammonium bicarbonate and sodium bicarbonate.

8. A method for preparing an emulsion-type large-particle acrylic pressure-sensitive adhesive, characterized in that: The steps include: Step 1: Add 0.4-0.8 parts of initiator to 5-10 parts of deionized water and stir to obtain an initiator solution; Step 2: Add 0.1-1 parts of emulsifier, 85-95 parts of acrylate soft monomer, 5-10 parts of acrylate hard monomer and 5-10 parts of functional monomer into 40-60 parts of deionized water, disperse at high speed for 10-15 minutes, then add 60% initiator solution, continue stirring to prepare a mixed pre-emulsion; Step 3: Add 0.1-0.3 parts of oxidant to 1-5 parts of deionized water, and stir to obtain an oxidant solution; add 0.1-0.3 parts of reductant to 1-5 parts of deionized water, and stir to obtain a reductant solution; Step 4: 80-120 parts of deionized water, 0.9-4 parts of emulsifier and 0.1-0.5 parts of pH regulator are mixed and stirred evenly in a reaction kettle, heated to 80° C., and then the remaining initiator solution is added; Step 5: Raise the temperature of the reactor to 82°C, start dripping the mixed pre-emulsion, keep the reaction temperature at 81-85°C, and keep warm after the dripping is completed; Step 6: After the heat preservation is finished, cool down, add the oxidant solution, and then add the reducing agent solution after 5-10 minutes, continue stirring and heat preservation, cool down to below 50°C, filter out the material, and obtain an emulsion type large particle size acrylic pressure-sensitive adhesive.

9. The method for preparing an emulsion-type large-particle acrylic pressure-sensitive adhesive according to claim 8, characterized in that: In the step 5, the dropping time is 3.5-4.5 hours, and the reaction is kept warm for 1 hour.

10. The method for preparing an emulsion-type large-particle acrylic pressure-sensitive adhesive according to claim 8, characterized in that: In the step six, the temperature is lowered to 70° C., and aqueous solutions of oxidant and reductant are added, and the heat preservation time is 30 minutes.

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