Solvent-type acrylate pressure-sensitive adhesive for battery label and preparation method of solvent-type acrylate pressure-sensitive adhesive

Abstract

The invention discloses a solvent type acrylate pressure-sensitive adhesive for a battery label. The solvent type acrylate pressure-sensitive adhesive is prepared from the following raw materials in parts by weight: 10 to 95 parts of butyl acrylate, 5 to 20 parts of methyl acrylate, 2 to 20 parts of vinyl acetate, 0.2 to 10 parts of special functional monomer, 105 to 310 parts of solvent, 0.5 to 2 parts of initiator and 20 to 60 parts of tackifying resin, the special functional monomer is selected from aliphatic polyurethane polyacrylate and aromatic polyurethane polyacrylate, the functionality of the special functional monomer is greater than or equal to 2, and the number-average molecular weight is 500-20000. The special functional monomer in the pressure-sensitive adhesive is polyurethane acrylate, after the polyurethane acrylate is introduced into the pressure-sensitive adhesive through a polymerization reaction, a polar carbamate structure in polyurethane can improve the bonding performance of the pressure-sensitive adhesive to a base material, and a acrylate structure can improve the cohesive strength of the pressure-sensitive adhesive.

Description

Technical Field

[0001] The invention belongs to the technical field of acrylic ester pressure-sensitive adhesives, and in particular relates to a solvent-type acrylic ester pressure-sensitive adhesive for a battery label and a preparation method thereof. Background Art

[0002] Solvent-based acrylic pressure-sensitive adhesive is a high-performance adhesive that not only has good bonding properties, but also maintains viscosity over a wide temperature range. In the field of battery label applications, with the development of batteries, pressure-sensitive adhesives are required to have not only excellent initial adhesion properties to meet the requirements of rapid labeling of battery labels, but also, due to the large degree of curvature of cylindrical batteries, battery label adhesives must also have sufficient stickiness to ensure that there will be no warping or drawing after the battery is attached. In addition, battery label pressure-sensitive adhesives must also have sufficient cohesive strength to ensure that there will be no overflow or residual glue during the subsequent slitting and die-cutting processes. However, the current pressure-sensitive adhesives cannot meet the above requirements at the same time and need further improvement.

[0003] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0004] The object of the present invention is to provide a solvent-based acrylic pressure-sensitive adhesive for battery labels and a preparation method thereof. The solvent-based acrylic pressure-sensitive adhesive for battery labels in the present invention can effectively overcome the problems of glue overflow, glue residue and warping in the production process of traditional battery labels, and has excellent adhesion.

[0005] In order to achieve the above object, a technical solution provided by a specific embodiment of the present invention is as follows:

[0006] A solvent-based acrylic pressure-sensitive adhesive for battery labels, comprising the following raw materials in parts by weight: 10 to 95 parts of butyl acrylate, 5 to 20 parts of methyl acrylate, 2 to 20 parts of vinyl acetate, 0.2 to 10 parts of special functional monomers, 105 to 310 parts of solvents, 0.5 to 2 parts of initiators, and 20 to 60 parts of tackifying resins;

[0007] The special functional monomer is selected from aliphatic polyurethane multiacrylate and aromatic polyurethane multiacrylate, the functionality of the special functional monomer is ≥2, and the number average molecular weight is 500-20000.

[0008] In one or more embodiments of the present invention, the raw material further comprises 10 to 95 parts by weight of 2-ethylhexyl acrylate.

[0009] In one or more embodiments of the present invention, the tackifying resin is one or more of petroleum resin, rosin resin, and terpene phenol resin.

[0010] Another specific embodiment of the present invention provides a technical solution as follows:

[0011] A method for preparing a solvent-based acrylic pressure-sensitive adhesive for a battery label comprises the following steps:

[0012] Step 1, mixing 10 to 95 parts by weight of butyl acrylate, 5 to 20 parts by weight of methyl acrylate, 0.1 to 0.2 parts by weight of an initiator and 50 to 100 parts by weight of a solvent, and heating the mixture for a certain period of time under a protective atmosphere;

[0013] Step 2, adding 0.2 to 5 parts by weight of hydroxyethyl acrylate, 0.1 to 0.2 parts by weight of initiator and 1 to 2 parts of solvent, and heating to react for a certain time;

[0014] Step 3, adding 2 to 20 parts by weight of vinyl acetate, 0.1 to 0.2 parts by weight of initiator and 1 to 2 parts by weight of solvent, and heating to react for a certain time;

[0015] Step 4, adding 0.2 to 10 parts by weight of a special functional monomer, 0.2 to 1.4 parts by weight of an initiator and 2 to 6 parts by weight of a solvent, and heating to react for a certain period of time;

[0016] Step 5, adding 50 to 200 parts by weight of a solvent and 20 to 60 parts by weight of a tackifying resin, stirring evenly, and filtering to obtain a solvent-based acrylic pressure-sensitive adhesive for a battery label;

[0017] Wherein, the special functional monomer is selected from aliphatic polyurethane multiacrylate and aromatic polyurethane multiacrylate, the functionality of the special functional monomer is ≥2, and the number average molecular weight is 500-20000.

[0018] In one or more embodiments of the present invention, the reaction temperature in step 1 is 65-75° C., and the reaction time is 0.5-1.5 h.

[0019] In one or more embodiments of the present invention, when mixing the raw materials in step 1, 10 to 95 parts by weight of 2-ethylhexyl acrylate is also added.

[0020] In one or more embodiments of the present invention, the reaction temperature in step 2 is 75-78° C., and the reaction time is 0.5-1.0 h.

[0021] In one or more embodiments of the present invention, the reaction temperature in step 3 is 78-80° C., and the reaction time is 0.5-1.0 h.

[0022] In one or more embodiments of the present invention, the reaction temperature in step 4 is 80-84° C., and the reaction time is 1-3 h.

[0023] In one or more embodiments of the present invention, in step 5, the temperature is first lowered to 23-50° C., and then the solvent and the tackifying resin are added.

[0024] Compared with the prior art, the present invention introduces aliphatic polyurethane acrylate or aromatic polyurethane multiacrylate into the molecular chain structure of acrylic pressure-sensitive adhesive. The polar urethane structure in the polyurethane can improve the bonding performance of the pressure-sensitive adhesive to the substrate, and the multiacrylate structure can improve the cohesive strength of the pressure-sensitive adhesive, thereby effectively solving the problems of glue overflow, glue residue and warping in the production process of battery label pressure-sensitive adhesive. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0026] A specific embodiment of the present invention provides a solvent-based acrylic pressure-sensitive adhesive for battery labels, comprising the following raw materials in parts by weight: 10 to 95 parts of butyl acrylate, 5 to 20 parts of methyl acrylate, 2 to 20 parts of vinyl acetate, 0.2 to 10 parts of special functional monomers, 100 to 300 parts of solvents, 0.1 to 2 parts of initiators, and 20 to 60 parts of tackifying resins;

[0027] The special functional monomer is selected from aliphatic polyurethane multiacrylate and aromatic polyurethane multiacrylate, the functionality of the special functional monomer is ≥2, and the number average molecular weight is 500-20000.

[0028] Specifically, first, aliphatic polyurethane multiacrylate and aromatic polyurethane multiacrylate are selected as special functional monomers and added to the system. The polar urethane structure in the polyurethane can be used to improve the bonding performance of the pressure-sensitive adhesive to the substrate, and the multiacrylate structure can improve the cohesive strength of the pressure-sensitive adhesive.

[0029] Secondly, the functionality of the special functional monomer ≥ 2 is conducive to improving the cross-linking degree of the pressure-sensitive adhesive, thereby improving the cohesion and bonding strength of the pressure-sensitive adhesive. At the same time, it can also improve the hardness and flexibility of the pressure-sensitive adhesive, making it more suitable for bonding the curved surface of the battery.

[0030] In addition, by limiting the number average molecular weight of the special functional monomer, the pressure-sensitive adhesive can have better bonding properties. Too low a number average molecular weight will lead to insufficient cohesion, while too high a number average molecular weight may affect fluidity and wettability, thereby reducing bonding properties.

[0031] In a specific embodiment, the raw materials further include 10 to 95 parts by weight of 2-ethylhexyl acrylate.

[0032] Specifically, by using 2-ethylhexyl acrylate as a monomer in the polymerization reaction, the pressure-sensitive adhesive can have better adhesion and cohesive strength, while also taking the product price into consideration in practical applications.

[0033] In a specific embodiment, the solvent is one or more of ethyl acetate, butanone, acetone, n-hexane, cyclohexane, n-heptane, and petroleum ether.

[0034] Specifically, the above solvents can be selected to better dissolve the raw materials and adjust the viscosity of the pressure-sensitive adhesive. Petroleum ether is preferably petroleum ether with a boiling range of 60 to 90°C.

[0035] In a specific embodiment, the initiator is one or both of azobisisobutyronitrile and dibenzoyl peroxide.

[0036] In a specific embodiment, the tackifying resin is one or more of petroleum resin, rosin resin, and terpene phenol resin.

[0037] Specifically, the petroleum resin is preferably a petroleum resin with a softening point of 80 to 150° C. Selecting the above-mentioned tackifying resin can further improve the viscosity and cohesion of the pressure-sensitive adhesive, reduce the creep and deformation of the pressure-sensitive adhesive after curing, and improve the tack retention of the pressure-sensitive adhesive.

[0038] A specific embodiment of the present invention provides a method for preparing a solvent-based acrylic pressure-sensitive adhesive for a battery label, comprising steps 1-5.

[0039] Step 1: Mix 10 to 95 parts by weight of butyl acrylate, 5 to 20 parts by weight of methyl acrylate, 0.1 to 0.2 parts by weight of an initiator and 50 to 100 parts by weight of a solvent, and heat and react for a certain period of time under a protective atmosphere.

[0040] Specifically, in step 1, the reaction temperature is 65-75° C., the reaction time is 0.5-1.5 h, and the protective atmosphere is nitrogen, helium or argon. In addition, in step 1, 10-95 parts by weight of 2-ethylhexyl acrylate can also be added simultaneously.

[0041] Step 2, adding 0.2 to 5 parts by weight of hydroxyethyl acrylate, 0.1 to 0.2 parts by weight of initiator and 1 to 2 parts by weight of solvent, and heating to react for a certain time.

[0042] Specifically, in step 2, the reaction temperature is 75-78° C., and the reaction time is 0.5-1.0 h.

[0043] Step 3, adding 2 to 20 parts by weight of vinyl acetate, 0.1 to 0.2 parts by weight of initiator and 1 to 2 parts by weight of solvent, and heating to react for a certain time.

[0044] Specifically, in step 3, the reaction temperature is 78-80° C., and the reaction time is 0.5-1.0 h.

[0045] Step 4, adding 0.2 to 10 parts by weight of special functional monomer, 0.2 to 1.4 parts by weight of initiator and 2 to 6 parts by weight of solvent, and heating to react for a certain time.

[0046] Specifically, in step 4, the reaction temperature is 80-84° C., and the reaction time is 1-3 h.

[0047] Step 5, adding 50 to 200 parts by weight of solvent and 20 to 60 parts by weight of tackifying resin, stirring evenly, filtering, and obtaining a solvent-based acrylic pressure-sensitive adhesive for battery labels.

[0048] Specifically, in step 5, the temperature is first lowered to 23-50° C., and then the solvent and the tackifying resin are added.

[0049] The present invention is further described in detail below in conjunction with specific embodiments.

[0050] Example 1

[0051] In parts by weight, take 60 parts of butyl acrylate, 30 parts of 2-ethylhexyl acrylate, 15 parts of methyl acrylate, 0.15 parts of azobisisobutyronitrile and 105 parts of ethyl acetate, mix well and add into the reaction kettle, heat to 65°C under nitrogen atmosphere, and react for 1 hour.

[0052] Then, 0.4 parts of hydroxyethyl acrylate, 0.15 parts of azobisisobutyronitrile and 1.5 parts of ethyl acetate were mixed evenly and added into the reaction kettle. The temperature was raised to 75° C. and the reaction was carried out for 1 hour.

[0053] Then take 8 parts of vinyl acetate, 0.15 parts of azobisisobutyronitrile and 1.5 parts of ethyl acetate, mix them evenly and add them into the reactor, heat it to 78°C, and react for 1 hour.

[0054] Take 1 part of Guojing Chemical aliphatic polyurethane acrylic resin GU3001Z, 0.2 parts of azobisisobutyronitrile and 2 parts of ethyl acetate, mix them evenly and add them into the reactor, heat to 80°C and react for 3 hours.

[0055] The temperature of the reaction kettle was lowered to 50° C., and 125 parts of ethyl acetate and 49 parts of Guangxi Wuzhou Arakawa resin tackifier resin D125 were added, stirred evenly, and filtered to obtain a solvent-based acrylic pressure-sensitive adhesive for battery labels.

[0056] Example 2

[0057] In parts by weight, take 60 parts of butyl acrylate, 30 parts of 2-ethylhexyl acrylate, 15 parts of methyl acrylate, 0.15 parts of azobisisobutyronitrile and 105 parts of ethyl acetate, mix well and add into the reaction kettle, heat to 65°C under nitrogen atmosphere, and react for 1 hour.

[0058] Then, 0.4 parts of hydroxyethyl acrylate, 0.15 parts of azobisisobutyronitrile and 1.5 parts of ethyl acetate were mixed evenly and added into the reaction kettle. The temperature was raised to 75° C. and the reaction was carried out for 1 hour.

[0059] Then take 8 parts of vinyl acetate, 0.15 parts of azobisisobutyronitrile and 1.5 parts of ethyl acetate, mix them evenly and add them into the reactor, heat it to 78°C, and react for 1 hour.

[0060] Take 2 parts of Guojing Chemical aliphatic polyurethane acrylic resin GU3001Z, 0.2 parts of azobisisobutyronitrile and 2 parts of ethyl acetate, mix them evenly and add them into the reactor, heat to 80°C, and react for 3 hours.

[0061] The temperature of the reaction kettle was lowered to 50° C., and 125 parts of ethyl acetate and 49 parts of Guangxi Wuzhou Arakawa resin tackifier resin D125 were added, stirred evenly, and filtered to obtain a solvent-based acrylic pressure-sensitive adhesive for battery labels.

[0062] Example 3

[0063] In parts by weight, 95 parts of butyl acrylate, 10 parts of methyl acrylate, 0.15 parts of azobisisobutyronitrile and 105 parts of ethyl acetate were mixed evenly and added into a reaction kettle. Under a nitrogen atmosphere, the temperature was raised to 65° C. and the reaction was carried out for 1 hour.

[0064] Then, 0.4 parts of hydroxyethyl acrylate, 0.15 parts of azobisisobutyronitrile and 1.5 parts of ethyl acetate were mixed evenly and added into the reaction kettle. The temperature was raised to 75° C. and the reaction was carried out for 1 hour.

[0065] Then take 8 parts of vinyl acetate, 0.15 parts of azobisisobutyronitrile and 1.5 parts of ethyl acetate, mix them evenly and add them into the reactor, heat it to 78°C, and react for 1 hour.

[0066] Take 1 part of Guojing Chemical aliphatic polyurethane acrylic resin GU3001Z, 0.2 parts of azobisisobutyronitrile and 2 parts of ethyl acetate, mix them evenly and add them into the reactor, heat to 80°C and react for 3 hours.

[0067] The temperature of the reaction kettle was lowered to 50° C., and 125 parts of ethyl acetate and 49 parts of Guangxi Wuzhou Arakawa resin tackifier resin D125 were added, stirred evenly, and filtered to obtain a solvent-based acrylic pressure-sensitive adhesive for battery labels.

[0068] Example 4

[0069] In parts by weight, 95 parts of butyl acrylate, 10 parts of methyl acrylate, 0.15 parts of azobisisobutyronitrile and 105 parts of ethyl acetate were mixed evenly and added into a reaction kettle. Under a nitrogen atmosphere, the temperature was raised to 65° C. and the reaction was carried out for 1 hour.

[0070] Then, 0.4 parts of hydroxyethyl acrylate, 0.15 parts of azobisisobutyronitrile and 1.5 parts of ethyl acetate were mixed evenly and added into the reaction kettle. The temperature was raised to 75° C. and the reaction was carried out for 1 hour.

[0071] Then take 8 parts of vinyl acetate, 0.15 parts of azobisisobutyronitrile and 1.5 parts of ethyl acetate, mix them evenly and add them into the reactor, heat it to 78°C, and react for 1 hour.

[0072] Take 2 parts of Guojing Chemical aliphatic polyurethane acrylic resin GU3001Z, 0.2 parts of azobisisobutyronitrile and 2 parts of ethyl acetate, mix them evenly and add them into the reactor, heat to 80°C, and react for 3 hours.

[0073] The temperature of the reaction kettle was lowered to 50° C., and 125 parts of ethyl acetate and 49 parts of Guangxi Wuzhou Arakawa resin tackifier resin D125 were added, stirred evenly, and filtered to obtain a solvent-based acrylic pressure-sensitive adhesive for battery labels.

[0074] Example 5

[0075] In parts by weight, take 60 parts of butyl acrylate, 30 parts of 2-ethylhexyl acrylate, 15 parts of methyl acrylate, 0.15 parts of azobisisobutyronitrile and 105 parts of ethyl acetate, mix well and add into the reaction kettle, heat to 65°C under nitrogen atmosphere, and react for 1 hour.

[0076] Then, 0.4 parts of hydroxyethyl acrylate, 0.15 parts of azobisisobutyronitrile and 1.5 parts of ethyl acetate were mixed evenly and added into the reaction kettle. The temperature was raised to 75° C. and the reaction was carried out for 1 hour.

[0077] Then take 8 parts of vinyl acetate, 0.15 parts of azobisisobutyronitrile and 1.5 parts of ethyl acetate, mix them evenly and add them into the reactor, heat it to 78°C, and react for 1 hour.

[0078] Take 1 part of Guojing Chemical aliphatic polyurethane acrylic resin GU3010Z, 0.2 parts of azobisisobutyronitrile and 2 parts of ethyl acetate, mix them evenly and add them into the reactor, heat to 80°C and react for 3 hours.

[0079] The temperature of the reaction kettle was lowered to 50° C., and 125 parts of ethyl acetate and 49 parts of Guangxi Wuzhou Arakawa resin tackifier resin D125 were added, stirred evenly, and filtered to obtain a solvent-based acrylic pressure-sensitive adhesive for battery labels.

[0080] Example 6

[0081] In parts by weight, take 60 parts of butyl acrylate, 30 parts of 2-ethylhexyl acrylate, 15 parts of methyl acrylate, 0.15 parts of azobisisobutyronitrile and 105 parts of ethyl acetate, mix well and add into the reaction kettle, heat to 65°C under nitrogen atmosphere, and react for 1 hour.

[0082] Then, 0.4 parts of hydroxyethyl acrylate, 0.15 parts of azobisisobutyronitrile and 1.5 parts of ethyl acetate were mixed evenly and added into the reaction kettle. The temperature was raised to 75° C. and the reaction was carried out for 1 hour.

[0083] Then take 8 parts of vinyl acetate, 0.15 parts of azobisisobutyronitrile and 1.5 parts of ethyl acetate, mix them evenly and add them into the reactor, heat it to 78°C, and react for 1 hour.

[0084] Then take 2 parts of Guojing Chemical aliphatic polyurethane acrylic resin GU3010Z, 0.2 parts of azobisisobutyronitrile and 2 parts of ethyl acetate, mix them evenly and add them into the reactor, heat to 80°C, and react for 3 hours.

[0085] The temperature of the reaction kettle was lowered to 50° C., and 125 parts of ethyl acetate and 49 parts of Guangxi Wuzhou Arakawa resin tackifier resin D125 were added, stirred evenly, and filtered to obtain a solvent-based acrylic pressure-sensitive adhesive for battery labels.

[0086] Comparative Example 1

[0087] In parts by weight, take 60 parts of butyl acrylate, 30 parts of 2-ethylhexyl acrylate, 15 parts of methyl acrylate, 0.15 parts of azobisisobutyronitrile and 105 parts of ethyl acetate, mix well and add into the reaction kettle, heat to 65°C under nitrogen atmosphere, and react for 1 hour.

[0088] Then, 0.4 parts of hydroxyethyl acrylate, 0.15 parts of azobisisobutyronitrile and 1.5 parts of ethyl acetate were mixed evenly and added into the reaction kettle. The temperature was raised to 75° C. and the reaction was carried out for 1 hour.

[0089] Then take 8 parts of vinyl acetate, 0.15 parts of azobisisobutyronitrile and 1.5 parts of ethyl acetate, mix them evenly and add them into the reactor, heat it to 78°C, and react for 1 hour.

[0090] Take 0.2 parts of azobisisobutyronitrile and 2 parts of ethyl acetate, mix well and add into the reaction kettle, heat to 80°C, and react for 3 hours.

[0091] The temperature of the reaction kettle was lowered to 50° C., and 125 parts of ethyl acetate and 49 parts of Guangxi Wuzhou Arakawa resin tackifier resin D125 were added, stirred evenly, and filtered to obtain a solvent-based acrylic pressure-sensitive adhesive for battery labels.

[0092] Comparative Example 2

[0093] In parts by weight, take 60 parts of butyl acrylate, 30 parts of 2-ethylhexyl acrylate, 15 parts of methyl acrylate, 0.15 parts of azobisisobutyronitrile and 105 parts of ethyl acetate, mix well and add into the reaction kettle, heat to 65°C under nitrogen atmosphere, and react for 1 hour.

[0094] Then, 0.4 parts of hydroxyethyl acrylate, 0.15 parts of azobisisobutyronitrile and 1.5 parts of ethyl acetate were mixed evenly and added into the reaction kettle. The temperature was raised to 75° C. and the reaction was carried out for 1 hour.

[0095] Then take 8 parts of vinyl acetate, 0.15 parts of azobisisobutyronitrile and 1.5 parts of ethyl acetate, mix them evenly and add them into the reactor, heat it to 78°C, and react for 1 hour.

[0096] Then take 1 part of 1,6-hexanediol diacrylate, 0.2 parts of azobisisobutyronitrile and 2 parts of ethyl acetate, mix them evenly and add them into the reactor, heat it to 80°C, and react for 3 hours.

[0097] The temperature of the reaction kettle was lowered to 50° C., and 125 parts of ethyl acetate and 49 parts of Guangxi Wuzhou Arakawa resin tackifier resin D125 were added, stirred evenly, and filtered to obtain a solvent-based acrylic pressure-sensitive adhesive for battery labels.

[0098] Comparative Example 3

[0099] In parts by weight, take 60 parts of butyl acrylate, 30 parts of 2-ethylhexyl acrylate, 15 parts of methyl acrylate, 0.15 parts of azobisisobutyronitrile and 105 parts of ethyl acetate, mix well and add into the reaction kettle, heat to 65°C under nitrogen atmosphere, and react for 1 hour.

[0100] Then, 0.4 parts of hydroxyethyl acrylate, 0.15 parts of azobisisobutyronitrile and 1.5 parts of ethyl acetate were mixed evenly and added into the reaction kettle. The temperature was raised to 75° C. and the reaction was carried out for 1 hour.

[0101] Then take 8 parts of vinyl acetate, 0.15 parts of azobisisobutyronitrile and 1.5 parts of ethyl acetate, mix them evenly and add them into the reactor, heat it to 78°C, and react for 1 hour.

[0102] Then take 1 part of trimethylolpropane triacrylate, 0.2 parts of azobisisobutyronitrile and 2 parts of ethyl acetate, mix them evenly and add them into the reactor, heat it to 80°C and react for 3 hours.

[0103] The temperature of the reaction kettle was lowered to 50° C., and 125 parts of ethyl acetate and 49 parts of Guangxi Wuzhou Arakawa resin tackifier resin D125 were added, stirred evenly, and filtered to obtain a solvent-based acrylic pressure-sensitive adhesive for battery labels.

[0104] The solvent-based acrylic pressure-sensitive adhesive for the battery labels in each embodiment and each comparative example was made into an adhesive tape and the performance was tested according to the general testing method in the industry. The test results are shown in Table 1.

[0105] Table 1 Performance test results

[0106]

[0107] It can be seen from Table 1 that when no special functional monomer is added to Comparative Example 1, the pressure-sensitive adhesive exhibits a slight warping phenomenon, and the adhesion, peeling force, and holding force are all weaker than those of the embodiments of the present invention, indicating that the present invention can effectively improve the cohesive energy and bonding performance of the pressure-sensitive adhesive by introducing polyurethane multiacrylate, and the overall performance is improved.

[0108] Comparative Examples 2 and 3 both used multi-acrylate monomers with a number average molecular weight of less than 500 to 20,000. In the performance test, the pressure-sensitive adhesive showed warping and residual adhesive, and the adhesion and holding power were reduced, indicating that the present invention can further improve the comprehensive performance of the pressure-sensitive adhesive by limiting the number average molecular weight and functionality of the special functional monomer.

[0109] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0110] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A solvent-based acrylic pressure-sensitive adhesive for battery labels, characterized in that: The method comprises the following raw materials in parts by weight: 10 to 95 parts of butyl acrylate, 5 to 20 parts of methyl acrylate, 2 to 20 parts of vinyl acetate, 0.2 to 10 parts of special functional monomer, 105 to 310 parts of solvent, 0.5 to 2 parts of initiator and 20 to 60 parts of tackifying resin; The special functional monomer is selected from aliphatic polyurethane multiacrylate and aromatic polyurethane multiacrylate, the functionality of the special functional monomer is ≥2, and the number average molecular weight is 500-20000.

2. The solvent-based acrylic pressure-sensitive adhesive for battery labels according to claim 1, characterized in that: The raw materials also include 10 to 95 parts by weight of 2-ethylhexyl acrylate.

3. The solvent-based acrylic pressure-sensitive adhesive for battery labels according to claim 1, characterized in that: The tackifying resin is one or more of petroleum resin, rosin resin and terpene phenol resin.

4. A method for preparing a solvent-based acrylic pressure-sensitive adhesive for battery labels, characterized in that: The steps include: Step 1, mixing 10 to 95 parts by weight of butyl acrylate, 5 to 20 parts by weight of methyl acrylate, 0.1 to 0.2 parts by weight of an initiator and 50 to 100 parts by weight of a solvent, and heating the mixture for a certain period of time under a protective atmosphere; Step 2, adding 0.2 to 5 parts by weight of hydroxyethyl acrylate, 0.1 to 0.2 parts by weight of initiator and 1 to 2 parts by weight of solvent, and heating to react for a certain time; Step 3, adding 2 to 20 parts by weight of vinyl acetate, 0.1 to 0.2 parts by weight of initiator and 1 to 2 parts by weight of solvent, and heating to react for a certain time; Step 4, adding 0.2 to 10 parts by weight of a special functional monomer, 0.2 to 1.4 parts by weight of an initiator and 2 to 6 parts by weight of a solvent, and heating to react for a certain period of time; Step 5, adding 50 to 200 parts by weight of a solvent and 20 to 60 parts by weight of a tackifying resin, stirring evenly, and filtering to obtain a solvent-based acrylic pressure-sensitive adhesive for a battery label; Wherein, the special functional monomer is selected from aliphatic polyurethane multiacrylate and aromatic polyurethane multiacrylate, the functionality of the special functional monomer is ≥2, and the number average molecular weight is 500-20000.

5. The solvent-based acrylic pressure-sensitive adhesive for battery labels according to claim 4, characterized in that: In step 1, the reaction temperature is 65-75° C. and the reaction time is 0.5-1.5 h.

6. The solvent-based acrylic pressure-sensitive adhesive for battery labels according to claim 4, characterized in that: When mixing the raw materials in step 1, 10 to 95 parts by weight of 2-ethylhexyl acrylate is also added.

7. The solvent-based acrylic pressure-sensitive adhesive for battery labels according to claim 4, characterized in that: In step 2, the reaction temperature is 75-78° C. and the reaction time is 0.5-1.0 h.

8. The solvent-based acrylic pressure-sensitive adhesive for battery labels according to claim 4, characterized in that: In step 3, the reaction temperature is 78-80° C. and the reaction time is 0.5-1.0 h.

9. The solvent-based acrylic pressure-sensitive adhesive for battery labels according to claim 4, characterized in that: In step 4, the reaction temperature is 80-84° C. and the reaction time is 1-3 h.

10. The solvent-based acrylic pressure-sensitive adhesive for battery labels according to claim 4, characterized in that: In step 5, the temperature is first lowered to 23-50° C., and then the solvent and tackifying resin are added.

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