A method for preparing a uv-debondable acrylic pressure sensitive adhesive

Abstract

The application discloses a preparation method of UV tack-reducing acrylic pressure-sensitive adhesive, and belongs to the field of curing coating. The method comprises the following steps: preparing mixture A and fluorine-containing mixture B by respectively reacting acrylate monomers with an initiator and a solvent; mixing the two mixtures; and stirring to prepare the pressure-sensitive adhesive by adding a crosslinking agent and a photoinitiator. In the method, toluene and ethyl acetate are preferably used as the solvents, azobisisobutyronitrile is used as the initiator, N-hydroxymethyl acrylamide and 1-hydroxycyclohexyl phenyl ketone are respectively used as the crosslinking agent and the photoinitiator. The preparation method does not need to add a multi-functional diluent, and solves the problem of poor compatibility; the formulation is optimized, the initial adhesion is improved, and the residual adhesive is reduced; the fluorine-containing component endows the adhesive layer with hydrophobicity and improves the stain resistance. The application solves the problems of poor compatibility, insufficient initial adhesion, residual adhesive and insufficient surface cleanliness of the existing UV tack-reducing acrylic pressure-sensitive adhesive by reasonably designing the molecular structure and the formulation.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of curing coatings, and particularly relates to a preparation method of UV tack-reducing acrylic pressure-sensitive adhesive. BACKGROUND

[0002] With the rapid development of the fields of electronic manufacturing and semiconductor packaging, UV tack-reducing adhesive, as an important functional adhesive, is widely used in precise device processing and wafer cutting due to its characteristic of realizing tackiness regulation through ultraviolet irradiation. At present, the mainstream UV tack-reducing adhesive is usually prepared by compounding an acrylate polymer as a base material with a multi-functional diluent, a photoinitiator and a curing agent. Although this preparation process can meet the basic use requirements, it exposes a series of technical bottlenecks to be solved in the actual application process.

[0003] From the perspective of composition, the commonly used multi-functional diluent in the system has compatibility limitations with the polymer matrix. When the adhesive tape is combined with the adherend, the small molecule multi-functional diluent will gradually migrate to the interface, resulting in a significant decrease in the initial tackiness of the adhesive. At the same time, after ultraviolet curing and crosslinking, the migration and residue of the multi-functional diluent are prone to cause the problem of residual adhesive.

[0004] In terms of performance, the tack-reducing tape prepared from the UV tack-reducing adhesive generally has the defect of insufficient initial tack. Researchers improve the initial tack performance by reducing the weight average molecular weight of the adhesive, but this method weakens the cohesion of the adhesive layer, causing adhesive residue during peeling.

[0005] In addition, the surface of the tack-reducing acrylic pressure-sensitive adhesive is easy to adsorb dust particles in the environment due to its chemical properties, which not only affects the appearance quality of the product, but also may potentially threaten the performance stability of electronic components.

[0006] In the face of the above technical problems, it is urgent to develop a UV tack-reducing acrylic pressure-sensitive adhesive to solve the problems of poor compatibility, insufficient initial tack, residual adhesive and insufficient surface cleanliness of the existing UV tack-reducing acrylic pressure-sensitive adhesive from the aspects of molecular structure design, formula optimization and the like. SUMMARY

[0007] Based on the deficiencies of the prior art, the present application provides a preparation method of UV tack-reducing acrylic pressure-sensitive adhesive, which aims to solve the problems of poor compatibility, insufficient initial tack, residual adhesive and insufficient surface cleanliness of the existing UV tack-reducing acrylic pressure-sensitive adhesive.

[0008] To achieve the above purpose, the present application provides the following technical scheme:

[0009] A preparation method of UV tack-reducing acrylic pressure-sensitive adhesive, comprising the following preparation steps:

[0010] S1, 35-45 parts by mass of methyl acrylate, 35-45 parts by mass of butyl acrylate, 15-25 parts by mass of hydroxyethyl acrylate are mixed, and are called total monomers, then 25%-40% of the total monomers are added to a reaction vessel together with 15-25 parts by mass of acrylic acid, 0.04-0.06 parts by mass of initiator and 180-220 parts by mass of solvent, under a protective atmosphere, warmed to 70-80°C, mechanically stirred for 50-70 min, then the remaining total monomers are mixed uniformly with 0.1-0.2 parts by mass of initiator, slowly added dropwise to the reaction vessel under mechanical stirring, after the dropwise addition is completed, continue to warm for 3 h, to obtain a mixture A;

[0011] S2, 35-45 parts by mass of butyl acrylate, 35-45 parts by mass of methyl acrylate, 15-25 parts by mass of acrylic acid, 20-40 parts by mass of perfluorooctyl ethyl acrylate, 0.1-0.2 parts by mass of initiator and 90-110 parts by mass of solvent are added to a reaction vessel, under a protective atmosphere, warmed to 80-90°C, mechanically stirred for 2.5-3.5 h, to obtain a fluorine-containing mixture B;

[0012] S3, 20-60 parts by mass of the mixture A described in step S1 are mixed with 8-12 parts by mass of the fluorine-containing mixture B described in step S2, stirred with a high-speed disperser at a rotational speed of 3500-4500 r / min, 0.8-1.2 parts by mass of crosslinking agent and 0.4-0.6 parts by mass of photoinitiator are added, then continue to stir at the same rotational speed for 15-25 min.

[0013] In this preparation process, there are steps with multiple steps of creativity, by adding the monomers and initiators in batches in step S1 to control the chain length of the polymer, when the initiator is insufficient, the polymerization reaction will be terminated, obtaining a polymer with small molecular weight, synthesizing an acrylate polymer with low molecular weight, and improving the initial adhesion of the pressure-sensitive adhesive. By step S2, the solvent is reduced, the reaction temperature is increased, and long-chain fluorine-containing acrylate polymers are obtained by directly adding monomers and initiators.

[0014] In step S3, the mixture A and the fluorine-containing mixture B are mixed uniformly by a high-speed disperser, to obtain an interpenetrating network structure, thereby reducing the residual glue.

[0015] The mixed glue is stirred uniformly by a high-speed disperser, without adding a multi-functional diluent, avoiding the problem of poor compatibility of the UV tack-reducing acrylic pressure-sensitive adhesive with the multi-functional diluent.

[0016] In addition, the fluoride has very high surface energy, so that the prepared adhesive has good hydrophobicity, increasing the water contact angle of the glue layer. When dust is adsorbed on the surface of the adhesive, the water bead on the surface can easily roll when washed with water, which can very well clean the dust, and can greatly improve the anti-fouling performance of the UV tack-reducing acrylic pressure-sensitive adhesive.

[0017] Further preferably, the preparation method of the UV tack-reducing acrylic pressure-sensitive adhesive is as follows.

[0018] Preferably, the solvent in step S1 is one of toluene and ethyl acetate.

[0019] Preferably, when the reaction container in step S1 is a four-necked flask, all the charging ports of the reaction container are sealed, a mechanical stirring rod is used for stirring, the reaction is performed for 50-70 min, the stirring speed is 80-100 r / min, subsequent incubation is performed for 3 h, the incubation is performed for 0-1 h at a stirring speed of 80-100 r / min, the incubation is performed for 1-2 h at a stirring speed of 140-160 r / min, the incubation is performed for 2-3 h at a stirring speed of 180-200 r / min.

[0020] The different stirring speeds in step S1 are set as follows: a slow stirring speed is required at the beginning to increase the chain length of the polymer, and as the reaction proceeds, the viscosity of the system becomes larger, and thus a high stirring speed is required to avoid gel aggregation.

[0021] Preferably, the stirring speed of the mechanical stirring in step S2 is 250-350 r / min.

[0022] In step S2, a high stirring speed is required at the beginning to obtain long-chain polymers, and to avoid gel aggregation due to the large viscosity of the system.

[0023] Preferably, the initiator in steps S1 and S2 is azobisisobutyronitrile.

[0024] Preferably, the crosslinking agent and the photoinitiator in step S3 are N-hydroxymethyl acrylamide and 1-hydroxycyclohexyl phenyl ketone, respectively.

[0025] Preferably, in step S3, 30 parts by mass of the mixture A in step S1 is mixed with 10 parts by mass of the fluorine-containing mixture B in step S2.

[0026] In addition, the present application provides a UV tack-reducing acrylic pressure-sensitive adhesive prepared by the above preparation method.

[0027] The present application has the following beneficial effects compared with the prior art:

[0028] (1) The present application controls the chain length of the polymer by adding monomers and initiators in batches. When the initiator is insufficient, the polymerization reaction is terminated, obtaining a polymer with a small molecular weight, synthesizing an acrylate polymer with a low molecular weight, and improving the initial adhesion of the pressure-sensitive adhesive. In addition, a fluorinated acrylate polymer with a large molecular weight is synthesized, which is mixed by a high-speed dispersing machine to obtain a network structure of the fluorinated acrylate polymer and the acrylate polymer, thereby reducing the residual glue.

[0029] (2) The present application uniformly stirs the mixed glue by a high-speed dispersing machine, without adding a multi-functional diluent, thereby avoiding the poor compatibility of the UV tack-reducing acrylate pressure-sensitive adhesive and the multi-functional diluent.

[0030] (3) The fluoride has a very high surface energy, so that the prepared adhesive has good hydrophobicity, increases the water contact angle of the glue layer, and when the adhesive surface adsorbs dust, the water bead on the surface is easy to roll, which can well wash away the dust, and can greatly improve the anti-pollution performance of the UV tack-reducing acrylate pressure-sensitive adhesive.

[0031] (4) By adjusting the formula, the problems of poor compatibility, insufficient initial adhesion, residual glue and insufficient surface cleanliness are solved. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 Viscosity and initial adhesion test results of Examples 1-7 and Comparative Example 1;

[0033] Figure 2 Water contact angle of the UV tack-reducing acrylate pressure-sensitive adhesive prepared in Examples 1-7 and Comparative Example 2 coated on a PET substrate. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below. The following content is only an example and description of the concept of the present application. Those skilled in the art can make various modifications or supplements to the described specific implementation cases or use similar ways instead, as long as they do not deviate from the concept of the present application or exceed the scope defined by the present claims, which should belong to the protection scope of the present application.

[0035] The above preparation method of the present application will be described below through specific examples.

[0036] Example 1

[0037] The present embodiment provides a preparation method of a UV tack-reducing acrylate pressure-sensitive adhesive, which comprises the following steps:

[0038] S1, 40 parts by mass of methyl acrylate, 40 parts by mass of butyl acrylate, 20 parts by mass of hydroxyethyl acrylate are mixed and called total monomer, then 25% of the total monomer is added into a reaction vessel together with 20 parts by mass of acrylic acid, 0.05 parts by mass of initiator and 200 parts by mass of solvent, under a protective atmosphere, the temperature is raised to 75℃, mechanical stirring is carried out for 1h, then the remaining total monomer is mixed uniformly with 0.15 parts by mass of initiator, under mechanical stirring, it is slowly dropped into the reaction vessel, after the dropping is completed, the temperature is kept for 3h, to obtain mixture A;

[0039] S2, 40 parts by mass of butyl acrylate, 40 parts by mass of methyl acrylate, 20 parts by mass of acrylic acid, 20 parts by mass of perfluorooctyl ethyl acrylate, 0.15 parts by mass of initiator and 100 parts by mass of solvent are added into a reaction vessel, under a protective atmosphere, the temperature is raised to 85℃, mechanical stirring is carried out for 3h, to obtain fluorine-containing mixture B;

[0040] S3, 20 parts by mass of mixture A in step S1 is mixed with 10 parts by mass of fluorine-containing mixture B in step S2, a high-speed disperser is used to stir at a speed of 4000r / min, 1 part by mass of crosslinking agent and 0.5 parts by mass of photoinitiator are added, then the stirring is continued for 20min.

[0041] In the above steps S1 and S2, the solvent is ethyl acetate;

[0042] In the above steps S1 and S2, the reaction vessel is a four-necked flask, the feeding ports of the reaction vessel are all sealed, a mechanical stirring rod is used for stirring, the stirring speed is 100r / min, the reaction is carried out for 0~1h, the temperature is kept for 3h, the stirring speed is 100r / min within 0~1h, the stirring speed is 150r / min within 1~2h, and the stirring speed is 200r / min within 2~3h;

[0043] In the above step S2, the stirring speed of mechanical stirring is 300r / min;

[0044] In the above steps S1 and S2, the initiator is azobisisobutyronitrile;

[0045] In the above step S3, the crosslinking agent and the photoinitiator are N-hydroxymethyl acrylamide and 1-hydroxycyclohexyl phenyl ketone respectively.

[0046] According to the above preparation method, a UV tack-reducing acrylic pressure-sensitive adhesive is obtained.

[0047] Example 2

[0048] The present embodiment provides a preparation method of a UV tack-reducing acrylic pressure-sensitive adhesive, which comprises the following steps:

[0049] S1, 35 parts by mass of methyl acrylate, 35 parts by mass of butyl acrylate, 15 parts by mass of hydroxyethyl acrylate are mixed and called total monomer, then 30% of the total monomer is added into a reaction vessel together with 15 parts by mass of acrylic acid, 0.04 parts by mass of initiator and 180 parts by mass of solvent, under a protective atmosphere, the temperature is raised to 70℃, mechanical stirring is carried out for 50 min, then the remaining total monomer is mixed uniformly with 0.1 parts by mass of initiator, under mechanical stirring, it is slowly dropped into the reaction vessel, after the dropping is completed, the temperature is kept for 3 h, to obtain mixture A;

[0050] S2, 35 parts by mass of butyl acrylate, 35 parts by mass of methyl acrylate, 15 parts by mass of acrylic acid, 30 parts by mass of perfluorooctyl ethyl acrylate, 0.1 parts by mass of initiator and 90 parts by mass of solvent are added into a reaction vessel, under a protective atmosphere, the temperature is raised to 80℃, mechanical stirring is carried out for 2.5 h, to obtain fluorine-containing mixture B;

[0051] S3, 40 parts by mass of mixture A in step S1 is mixed with 8 parts by mass of fluorine-containing mixture B in step S2, a high-speed disperser is used to stir at a speed of 3500 r / min, 0.8 parts by mass of crosslinking agent and 0.4 parts by mass of photoinitiator are added, then the stirring is continued for 15 min.

[0052] In the above steps S1 and S2, the solvent is toluene;

[0053] In the above steps S1 and S2, the reaction vessel is a four-necked flask, the feeding ports of the reaction vessel are all sealed, a mechanical stirring rod is used for stirring, the stirring speed is 80 r / min, the reaction is carried out for 0~1 h, the temperature is kept for 3 h, the stirring speed is 80 r / min within 0~1 h, the stirring speed is 140 r / min within 1~2 h, and the stirring speed is 180 r / min within 2~3 h;

[0054] In the above step S2, the stirring speed of mechanical stirring is 250 r / min;

[0055] In the above steps S1 and S2, the initiator is azobisisobutyronitrile;

[0056] In the above step S3, the crosslinking agent and the photoinitiator are N-hydroxymethyl acrylamide and 1-hydroxycyclohexyl phenyl ketone respectively.

[0057] According to the above preparation method, a UV debonding acrylic pressure-sensitive adhesive is obtained.

[0058] Example 3

[0059] The present example provides a preparation method of a UV debonding acrylic pressure-sensitive adhesive, which comprises the following steps:

[0060] S1, 45 parts by mass of methyl acrylate, 45 parts by mass of butyl acrylate, 25 parts by mass of hydroxyethyl acrylate are mixed and called total monomer, then 40% of the total monomer is added into a reaction vessel together with 25 parts by mass of acrylic acid, 0.06 parts by mass of initiator and 220 parts by mass of solvent, under a protective atmosphere, the temperature is raised to 80°C, mechanical stirring is carried out for 70 min, then the remaining total monomer is mixed uniformly with 0.2 parts by mass of initiator, under mechanical stirring, it is slowly dropped into the reaction vessel, after the dropping is completed, the temperature is kept for 3 h, to obtain mixture A;

[0061] S2, 45 parts by mass of butyl acrylate, 45 parts by mass of methyl acrylate, 25 parts by mass of acrylic acid, 40 parts by mass of perfluorooctyl ethyl acrylate, 0.2 parts by mass of initiator and 110 parts by mass of solvent are added into a reaction vessel, under a protective atmosphere, the temperature is raised to 90°C, mechanical stirring is carried out for 3.5 h, to obtain fluorine-containing mixture B;

[0062] S3, 60 parts by mass of mixture A in step S1 is mixed with 12 parts by mass of fluorine-containing mixture B in step S2, a high-speed disperser is used to stir at a speed of 4500 r / min, 1.2 parts by mass of crosslinking agent and 0.6 parts by mass of photoinitiator are added, then the stirring is continued for 20 min.

[0063] In the above steps S1 and S2, the solvent is ethyl acetate;

[0064] In the above steps S1 and S2, the reaction vessel is a four-necked flask, the feeding ports of the reaction vessel are all sealed, a mechanical stirring rod is used for stirring, the stirring speed is 90 r / min, the reaction is carried out for 0-1 h, then the temperature is kept for 3 h, the stirring speed is 90 r / min for 0-1 h, the stirring speed is 160 r / min for 1-2 h, the stirring speed is 190 r / min for 2-3 h;

[0065] In the above step S2, the stirring speed of mechanical stirring is 350 r / min;

[0066] In the above steps S1 and S2, the initiator is azobisisobutyronitrile;

[0067] In the above step S3, the crosslinking agent and the photoinitiator are N-hydroxymethyl acrylamide and 1-hydroxycyclohexyl phenyl ketone respectively.

[0068] According to the above preparation method, a UV adhesion-reducing acrylic pressure-sensitive adhesive is obtained.

[0069] Example 4

[0070] The difference between example 1 and example 4 is that in step S3, the adding amount of mixture A and fluorine-containing mixture B is 30 parts by mass and 10 parts by mass respectively.

[0071] Example 5

[0072] The difference from Example 1 is that the addition amount of mixture A and fluorine-containing mixture B in step S3 is 40 parts by mass and 10 parts by mass, respectively.

[0073] Example 6

[0074] The difference from Example 1 is that the addition amount of mixture A and fluorine-containing mixture B in step S3 is 50 parts by mass and 10 parts by mass, respectively.

[0075] Example 7

[0076] The difference from Example 1 is that the addition amount of mixture A and fluorine-containing mixture B in step S3 is 60 parts by mass and 10 parts by mass, respectively.

[0077] Comparative Example 1

[0078] The difference from Example 1 is that the total monomer and initiator are added at one time in step S1.

[0079] Comparative Example 2

[0080] The present embodiment provides a preparation method of a UV debonding acrylic pressure-sensitive adhesive, and the preparation method comprises the following steps:

[0081] S1, 40 parts by mass of methyl acrylate, 40 parts by mass of butyl acrylate, and 20 parts by mass of hydroxyethyl acrylate are mixed and called total monomer, then 25% of the total monomer is added into a reaction container together with 20 parts by mass of acrylic acid, 0.05 parts by mass of initiator, and 200 parts by mass of solvent, under a protective atmosphere, the temperature is raised to 75°C, and mechanical stirring is carried out for 1 h, then the remaining total monomer is mixed uniformly with 0.15 parts by mass of initiator, and is slowly dropped into the reaction container under mechanical stirring, after the dropping is completed, the temperature is continued to be kept for 3 h, and mixture A is prepared;

[0082] S2, mixture A is stirred at a speed of 4000 r / min by using a high-speed dispersion machine, 1 part by mass of crosslinking agent and 0.5 parts by mass of photoinitiator are added, and then the stirring is continued for 20 min.

[0083] The solvent in steps S1 and S2 is ethyl acetate;

[0084] When the reaction container in step S1 is a four-necked flask, all the feeding ports of the reaction container are sealed, a mechanical stirring rod is used for stirring, the reaction is carried out for 0-1 h, the stirring speed is 100 r / min, the temperature is kept for 3 h, the stirring speed is 100 r / min within 0-1 h, the stirring speed is 150 r / min within 1-2 h, and the stirring speed is 200 r / min within 2-3 h;

[0085] The initiator in step S1 is azobisisobutyronitrile;

[0086] The crosslinking agent and photoinitiator in step S2 are N-hydroxymethyl acrylamide and 1-hydroxycyclohexyl phenyl ketone, respectively.

[0087] A UV debonding acrylic pressure-sensitive adhesive is obtained according to the above preparation method.

[0088] Comparative Example 3

[0089] The present comparative example provides a preparation method for preparing a UV debonding acrylic pressure-sensitive adhesive by adding a multi-functional diluent, comprising the following steps:

[0090] S1, 40 parts by mass of methyl acrylate, 40 parts by mass of butyl acrylate, and 20 parts by mass of hydroxyethyl acrylate are mixed and referred to as total monomers, then 25% of the total monomers are mixed with 20 parts by mass of acrylic acid, 0.05 parts by mass of initiator, 30 parts by mass of trimethylolpropane triacrylate, and 200 parts by mass of solvent, and then added into a reaction vessel under a protective atmosphere, heated to 75°C, and mechanically stirred for 1 h, then the remaining total monomers are mixed with 0.15 parts by mass of initiator and slowly added into the reaction vessel under mechanical stirring, after the addition is completed, the temperature is maintained for 3 h, and a mixture A is prepared;

[0091] S2, 40 parts by mass of butyl acrylate, 40 parts by mass of methyl acrylate, 20 parts by mass of acrylic acid, 20 parts by mass of perfluorooctyl ethyl acrylate, 0.15 parts by mass of initiator, 30 parts by mass of trimethylolpropane triacrylate, and 100 parts by mass of solvent are added into a reaction vessel, heated to 85°C under a protective atmosphere, mechanically stirred for 3 h, and a fluorine-containing mixture B is prepared;

[0092] S3, 20 parts by mass of the mixture A in step S1 are mixed with 10 parts by mass of the fluorine-containing mixture B in step S2, stirred at a speed of 4000 r / min by a high-speed disperser, 1 part by mass of a crosslinking agent and 0.5 parts by mass of a photoinitiator are added, and then the stirring is continued for 20 min.

[0093] The solvent in steps S1 and S2 is ethyl acetate;

[0094] When the reaction vessel in steps S1 and S2 is a four-necked flask, all the charging ports of the reaction vessel are sealed, a mechanical stirrer is used for stirring, the stirring speed is 100 r / min for 0-1 h, the temperature is maintained for 3 h, the stirring speed is 100 r / min for 0-1 h, the stirring speed is 150 r / min for 1-2 h, and the stirring speed is 200 r / min for 2-3 h;

[0095] The stirring speed of the mechanical stirring in step S2 is 300 r / min.

[0096] The initiator in steps S1 and S2 is azobisisobutyronitrile.

[0097] The crosslinking agent and the photoinitiator in step S3 are N-hydroxymethyl acrylamide and 1-hydroxycyclohexyl phenyl ketone, respectively.

[0098] A UV tack-reducing acrylic pressure-sensitive adhesive is obtained according to the above preparation method.

[0099] Comparative Example 4

[0100] The difference from Example 1 is that the stirring speed in step S1 is always 100 r / min.

[0101] The mixture A obtained in Comparative Example 4 shows the phenomenon of aggregated gel.

[0102] Comparative Example 5

[0103] The difference from Example 1 is that the stirring speed in step S2 is always 100 r / min.

[0104] The mixture A obtained in Comparative Example 4 shows the phenomenon of aggregated gel.

[0105] Comparative Example 6

[0106] The difference from Example 1 is that step S3 is not stirred with a high-speed disperser, but stirred with a mechanical rod at a stirring speed of 600 r / min for 20 min to prepare a UV tack-reducing acrylic pressure-sensitive adhesive.

[0107] Figure 1 The viscosity and tack force test results of Examples 1-7 and Comparative Example 1 are shown in Table 1. From the viscosity results, it can be seen that the present application controls the chain length of the polymer by adding the monomer and initiator in batches. When the initiator is insufficient, the polymerization reaction is terminated, and a polymer with a small molecular weight is obtained, thus synthesizing an acrylic ester polymer with a low molecular weight and improving the tack force of the pressure-sensitive adhesive. Therefore, the more the polymer with a small molecular weight is added, the greater the tack force will be.

[0108] In addition, it can be seen from the results in Comparative Example 1 that the tack force is significantly smaller than that of the examples, because the monomer and initiator are added together and all at once, which forms long-chain macromolecules, thereby reducing the tack force.

[0109] The residual adhesive situation is evaluated according to "no residual adhesive (V) / slight residual adhesive (A) / severe residual adhesive (X)".

[0110] Table 1 is the residual adhesive evaluation of Example 1, Comparative Example 2 and Comparative Example 3

[0111] Sample Example 1 Comparative Example 2 Comparative Example 3 Evaluation √ △ ×

[0112] From Table 1, it can be seen that the adhesive residue of Example 1 is significantly less than that of Comparative Examples 2 and 3.

[0113] The comparison between Example 1 and Comparative Example 3 shows that the adhesive residue is reduced by designing the network structure of the fluorine-containing acrylate polymer and the acrylate polymer interpenetration. In addition, it can be shown that the UV tack-reducing acrylic pressure-sensitive adhesive prepared in the present application has both high initial adhesion and solves the problem of easy residue left by acrylate polymers with low molecular weight.

[0114] The comparison between Example 1 and Comparative Example 3 shows that the present application does not add a multi-functional diluent, and the mixed colloids are stirred uniformly by a high-speed disperser, which solves the problem of poor compatibility of the UV tack-reducing acrylic pressure-sensitive adhesive with the multi-functional diluent, leading to the problem of adhesive residue.

[0115] In addition, the UV tack-reducing acrylic pressure-sensitive adhesive prepared in Example 1 and Comparative Example 6 is coated on a PET substrate, and after coating, the surface of the substrate is uniform in the example, while the coating is uneven in the comparative example.

[0116] This shows that the present application does not add a multi-functional diluent, and the mixed colloids are stirred uniformly by a high-speed disperser, while the use of a high-speed disperser leads to poor uniformity of the film layer coated by the colloids. This shows that the high-speed disperser stirs the mixed colloids uniformly, and without adding a multi-functional diluent, the problem of poor compatibility of the UV tack-reducing acrylic pressure-sensitive adhesive with the multi-functional diluent is solved.

[0117] Figure 2 The water contact angle of the UV tack-reducing acrylic pressure-sensitive adhesive prepared in Examples 1-7 and Comparative Example 2 is tested by coating it on a PET substrate. It can be seen that the water contact angle in the examples is significantly larger than that in the comparative example, and the water contact angle of Examples 1-7 ranges from 110 to 131°. This shows that the fluoride has very high surface energy, making the prepared adhesive have good hydrophobicity, increasing the water contact angle of the adhesive layer. When dust is adsorbed on the surface of the adhesive, the water bead on the surface is easy to roll, which can effectively clean the dust, greatly improving the anti-fouling performance of the UV tack-reducing acrylic pressure-sensitive adhesive.

Claims

1. A method for preparing a UV-debondable acrylic pressure sensitive adhesive, characterized in that, The preparation steps include the following: S1. Mix 35-45 parts by weight of methyl acrylate, 35-45 parts by weight of butyl acrylate, and 15-25 parts by weight of hydroxyethyl acrylate, and refer to this mixture as the total monomer. Then, add 25%-40% of the total monomer, along with 15-25 parts by weight of acrylic acid, 0.04-0.06 parts by weight of initiator, and 180-220 parts by weight of solvent into a reaction vessel. Under a protective atmosphere, heat the mixture to 70-80°C and stir mechanically for 50-70 minutes. Then, mix the remaining total monomer with 0.1-0.2 parts by weight of initiator until homogeneous, and slowly add the mixture dropwise into the reaction vessel while stirring with a mechanical stirrer. After the addition is complete, continue to maintain the temperature for 3 hours to obtain mixture A. S2, 35-45 parts by weight of butyl acrylate, 35-45 parts by weight of methyl acrylate, 15-25 parts by weight of acrylic acid, 20-40 parts by weight of perfluorooctyl ethyl acrylate, 0.1-0.2 parts by weight of initiator and 90-110 parts by weight of solvent are added to a reaction vessel. Under a protective atmosphere, the temperature is raised to 80-90°C, and the mixture is mechanically stirred for 2.5-3.5 hours to obtain fluorine-containing mixture B. S3. Mix 20-60 parts by weight of the mixture A described in step S1 with 8-12 parts by weight of the fluorine-containing mixture B described in step S2, stir with a high-speed disperser at a speed of 3500-4500 r / min, add 0.8-1.2 parts by weight of crosslinking agent and 0.4-0.6 parts by weight of photoinitiator, and then continue stirring for 15-25 min. When the reaction vessel in step S1 is a four-necked flask, the feeding port of the reaction vessel is completely sealed, and a mechanical stirring rod is used for stirring. The reaction is carried out for 50-70 minutes at a stirring speed of 80-100 r / min, followed by a 3-hour heat preservation period, a 0-1 hour heat preservation period at a stirring speed of 80-100 r / min, a 1-2 hour heat preservation period at a stirring speed of 140-160 r / min, and a 2-3 hour heat preservation period at a stirring speed of 180-200 r / min. The stirring speed of the mechanical stirring in step S2 is 250~350 r / min.

2. The preparation method of the UV-resistant acrylic pressure-sensitive adhesive according to claim 1, characterized in that, The solvent mentioned in steps S1 and S2 is one of toluene and ethyl acetate.

3. The preparation method of the UV-resistant acrylic pressure-sensitive adhesive according to claim 1, characterized in that, The initiator mentioned in steps S1 and S2 is azobisisobutyronitrile.

4. The preparation method of the UV-resistant acrylic pressure-sensitive adhesive according to claim 1, characterized in that... The crosslinking agent and photoinitiator mentioned in step S3 are N-hydroxymethylacrylamide and 1-hydroxycyclohexylphenyl ketone, respectively.

5. The preparation method of the UV-resistant acrylic pressure-sensitive adhesive according to claim 1, characterized in that, In step S3, 30 parts by mass of mixture A described in step S1 are mixed with 10 parts by mass of fluorine-containing mixture B described in step S2.

6. A UV-resistant acrylic pressure-sensitive adhesive prepared by the preparation method according to any one of claims 1 to 5.

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