Acrylate pressure-sensitive adhesive, acrylate pressure-sensitive adhesive film and preparation method of acrylate pressure-sensitive adhesive film

Abstract

The invention discloses an acrylate pressure-sensitive adhesive, an acrylate pressure-sensitive adhesive film and a preparation method of the acrylate pressure-sensitive adhesive film. The acrylate pressure-sensitive adhesive comprises the following raw materials in parts by weight: 500-900 parts of a (methyl) acrylic acid soft monomer, 400-800 parts of a (methyl) acrylic acid hard monomer A, 80-100 parts of acrylic acid, 5-15 parts of a (methyl) acrylic acid functional monomer, 1-10 parts of a (methyl) acrylic acid hard monomer B, 1800-4200 parts of a solvent and 5-10 parts of an initiator. The solvent is selected from the group consisting of n-hexane, cyclohexane, n-heptane, acetone, and isopropanol. Through matching of different solvents, the performance of the pressure-sensitive adhesive is adjusted, and the prepared acrylate pressure-sensitive adhesive has excellent adhesive force and cohesion, and is good in high temperature resistance and aging resistance, less in adhesive force reduction and free of obvious color difference.

Description

Technical Field

[0001] The invention belongs to the technical field of adhesives, and in particular relates to an acrylate pressure-sensitive adhesive, an acrylate pressure-sensitive adhesive film and a preparation method thereof. Background Art

[0002] The main advantages of solvent-based acrylic pressure-sensitive adhesive are good pressure sensitivity, adhesion, wettability, peeling resistance, creep shear resistance, oxidation resistance, corrosion resistance, etc. It has the advantages of a single system, stable performance, and simple synthesis process. It is widely used in the production of pressure-sensitive tapes, pressure-sensitive labels, double-sided tapes, stationery tapes, protective films, explosion-proof tapes, etc.

[0003] However, traditional pressure-sensitive adhesives are still lacking in high temperature resistance and aging resistance. Acrylic pressure-sensitive adhesive products exposed outdoors for a long time will fall off and turn yellow. In addition, conventional solvent-based acrylic pressure-sensitive adhesives usually use ethyl acetate or a mixed solvent of ethyl acetate and toluene as the dispersant of the system, and sometimes other benzene solvents are also used. During the synthesis process and subsequent coating steps, benzene substances are released, which causes great pollution to the environment and great harm to the human body.

[0004] 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

[0005] The purpose of the present invention is to provide an acrylate pressure-sensitive adhesive, an acrylate pressure-sensitive adhesive film and a preparation method thereof, and to improve the performance of the adhesive by adjusting the combination of monomers and solvents so as to make it suitable for places such as car covers that are exposed to the outdoors for a long time and require light transmission.

[0006] In order to achieve the above object, a technical solution provided by a specific embodiment of the present invention is as follows:

[0007] An acrylic pressure-sensitive adhesive comprises the following raw materials in parts by weight: 500-900 parts of (meth)acrylic soft monomer, 400-800 parts of (meth)acrylic hard monomer A, 80-100 parts of acrylic acid, 5-15 parts of (meth)acrylic functional monomer, 1-10 parts of (meth)acrylic hard monomer B, 1800-4200 parts of solvent, and 5-10 parts of initiator;

[0008] The solvent is selected from the group consisting of n-hexane, cyclohexane, n-heptane, acetone and isopropanol.

[0009] In one or more embodiments of the present invention, the (meth)acrylic soft monomer is one or more of isooctyl (meth)acrylate, butyl (meth)acrylate, and ethyl (meth)acrylate.

[0010] In one or more embodiments of the present invention, the (meth)acrylic hard monomer A is one or more of methyl (meth)acrylate, isobornyl (meth)acrylate, and cyclohexyl (meth)acrylate.

[0011] In one or more embodiments of the present invention, the (meth)acrylic hard monomer B is one or more of methyl (meth)acrylate, isobornyl (meth)acrylate, and cyclohexyl (meth)acrylate.

[0012] In one or more embodiments of the present invention, the (meth)acrylic functional monomer contains -COOH, -OH, amide group or unsaturated double bond group.

[0013] In one or more embodiments of the present invention, the (meth)acrylic functional monomer is one or more of hydroxyethyl (meth)acrylate, hydroxybutyl (meth)acrylate, acrylamide, N-vinyl caprolactam, acrylonitrile, N-vinyl pyrrolidone, (meth)acrylic acid, 2-carboxyethyl acrylate and 4-hydroxyvinyloxybenzophenone methacrylate.

[0014] In one or more embodiments of the present invention, the initiator is one or both of azobisisobutyronitrile and dibenzoyl peroxide.

[0015] Another specific embodiment of the present invention provides a technical solution as follows:

[0016] A method for preparing an acrylic pressure-sensitive adhesive comprises the following steps:

[0017] Step 1, taking (meth) acrylic acid soft monomer, (meth) acrylic acid hard monomer A, acrylic acid, (meth) acrylic acid functional monomer, (meth) acrylic acid hard monomer B and 1500-2000 parts by weight of solvent, mixing and adding into a reaction container, and keeping under a protective gas atmosphere;

[0018] Step 2, raising the temperature to 65-67° C., dissolving 1-2 parts by weight of an initiator in 10-20 parts by weight of a solvent, adding the mixture to a reaction vessel, and reacting for 1.2-1.8 hours;

[0019] Step 3, heating to 70-73°C, dissolving 1-2 parts by weight of initiator in 10-20 parts by weight of solvent, adding to the reaction vessel, and reacting for 0.8-1.2h;

[0020] Step 4, heating to 75-78°C, dissolving the remaining initiator in part of the solvent, adding the mixture to the reaction vessel, and reacting for 2.8-3.2h;

[0021] Step 5, cooling to 45-55° C., adding the remaining solvent, and stirring evenly to obtain an acrylic pressure-sensitive adhesive.

[0022] Another specific embodiment of the present invention provides a technical solution as follows:

[0023] An acrylic pressure-sensitive adhesive film comprises a substrate layer, an adhesive layer and a release layer which are stacked in sequence, wherein the adhesive layer raw material comprises 100 parts by weight of an acrylic pressure-sensitive adhesive, 0.13 to 0.18 parts by weight of a cross-linking agent and 0.4 to 0.6 parts by weight of a protective agent;

[0024] Wherein, the acrylic pressure-sensitive adhesive is the above-mentioned acrylic pressure-sensitive adhesive.

[0025] Another specific embodiment of the present invention provides a technical solution as follows:

[0026] A method for preparing an acrylic pressure-sensitive adhesive film comprises the following steps:

[0027] Mixing an acrylic pressure-sensitive adhesive, a cross-linking agent and a protective agent to obtain a rubber compound;

[0028] Apply the adhesive on the release layer and heat at 90-110°C for 3-5 minutes to form an adhesive layer;

[0029] A substrate layer is compounded on the adhesive layer to obtain an acrylic pressure-sensitive adhesive film.

[0030] Compared with the prior art, the present invention adjusts the performance of the pressure-sensitive adhesive by combining different solvents, and the prepared acrylic pressure-sensitive adhesive has excellent adhesion and cohesion, strong bonding force, good high temperature resistance and aging resistance, strong weather resistance, little adhesion loss, and no obvious color difference. DETAILED DESCRIPTION

[0031] 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 are clearly and completely described below. 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.

[0032] A specific embodiment of the present invention provides an acrylate pressure-sensitive adhesive, comprising the following raw materials in parts by weight: 500-900 parts of (meth)acrylic soft monomer, 400-800 parts of (meth)acrylic hard monomer A, 80-100 parts of acrylic acid, 5-15 parts of (meth)acrylic functional monomer, 1-10 parts of (meth)acrylic hard monomer B, 1800-4200 parts of solvent, and 5-10 parts of initiator.

[0033] Further, the (meth) acrylic acid soft monomer is one or more of (meth) acrylic acid isooctyl, (meth) acrylic acid butyl, (meth) acrylic acid ethyl ester; (meth) acrylic acid hard monomer A is one or more of (meth) acrylic acid methyl ester, (meth) acrylic acid isobornyl, (meth) acrylic acid cyclohexyl ester; (meth) acrylic acid hard monomer B is one or more of (meth) acrylic acid methyl ester, (meth) acrylic acid isobornyl, (meth) acrylic acid cyclohexyl ester; (meth) acrylic acid functional monomer contains -COOH, -OH, amide group or unsaturated double bond group, preferably, (meth) acrylic acid functional monomer is one or more of (meth) acrylic acid hydroxyethyl, (meth) acrylic acid hydroxybutyl, acrylamide, N-vinyl caprolactam, acrylonitrile, N-vinyl pyrrolidone, (meth) acrylic acid, 2-carboxyethyl acrylate, 4-hydroxyvinyloxybenzophenone methacrylate. The initiator is one or two of azobisisobutyronitrile and dibenzoyl peroxide. The solvent is selected from the group consisting of n-hexane, cyclohexane, n-heptane, acetone and isopropanol.

[0034] Specifically, the solvent selected in the present invention does not contain toluene, which reduces the emission of benzene substances and has little pollution to the environment. At the same time, by matching different monomers and solvents, the performance of the acrylic pressure-sensitive adhesive can be adjusted to make it have excellent adhesion and cohesion, and have good high temperature resistance and aging resistance.

[0035] Furthermore, in the acrylate pressure-sensitive adhesive, the specific types of (meth)acrylic acid hard monomer A and (meth)acrylic acid hard monomer B are different. (Meth)acrylic acid hard monomer A is used as the main body of the hard monomer to polymerize with the soft monomer, and (meth)acrylic acid hard monomer B is used in a small amount and mainly plays a regulating role, suppressing the degree of reaction and reducing the possibility of excessive reaction, thereby ensuring that the prepared acrylate pressure-sensitive adhesive has excellent performance.

[0036] Another specific embodiment of the present invention provides a method for preparing an acrylic pressure-sensitive adhesive, comprising steps 1-5.

[0037] Step 1: Take (meth)acrylic acid soft monomer, (meth)acrylic acid hard monomer A, acrylic acid, (meth)acrylic acid functional monomer, (meth)acrylic acid hard monomer B and 1500-2000 parts by weight of solvent, mix them evenly and add them into a reaction container, and keep it under a protective gas atmosphere.

[0038] Specifically, the protective gas is selected from nitrogen, helium and argon. After the raw materials are added into the reaction container, they are kept under the protective gas atmosphere for more than 30 minutes.

[0039] Step 2, raising the temperature to 65-67° C., dissolving 1-2 parts by weight of an initiator in 10-20 parts by weight of a solvent, adding the mixture to a reaction vessel, and reacting for 1.2-1.8 hours;

[0040] Step 3, heating to 70-73°C, dissolving 1-2 parts by weight of initiator in 10-20 parts by weight of solvent, adding to the reaction vessel, and reacting for 0.8-1.2h;

[0041] Step 4, heating to 75-78°C, dissolving the remaining initiator in 10-20 parts by weight of solvent, adding the mixture to the reaction vessel, and reacting for 2.8-3.2 hours;

[0042] Step 5, cooling to 45-55° C., adding the remaining solvent, and stirring evenly to obtain an acrylic pressure-sensitive adhesive.

[0043] Specifically, by carrying out multi-stage polymerization reactions at different temperatures, the raw materials can be fully reacted to prepare an acrylic pressure-sensitive adhesive with excellent performance.

[0044] Another specific embodiment of the present invention provides an acrylate pressure-sensitive adhesive film, comprising a substrate layer, an adhesive layer and a release layer stacked in sequence, wherein the adhesive layer raw materials include 100 parts by weight of an acrylate pressure-sensitive adhesive, 0.13 to 0.18 parts by weight of a cross-linking agent and 0.4 to 0.6 parts by weight of a protective agent.

[0045] Specifically, aluminum acetylacetonate is selected as the cross-linking agent, and acetylacetone is selected as the protective agent. Acetylacetone and aluminum acetylacetonate can form a coordination, which can prevent aluminum acetylacetonate from curing the acrylic pressure-sensitive adhesive during storage and transportation. When curing is required, acetylacetone is evaporated by heating, and aluminum acetylacetonate can undergo a curing process, which is beneficial to the storage and transportation of the acrylic pressure-sensitive adhesive.

[0046] Another specific embodiment of the present invention provides a method for preparing an acrylic pressure-sensitive adhesive film, the steps of which are as follows: mixing an acrylic pressure-sensitive adhesive, a cross-linking agent and a protective agent to obtain a rubber material, coating the rubber material on a release layer, and heating at 90 to 110° C. for 3 to 5 minutes to form an adhesive layer; and compounding a substrate layer on the adhesive layer to obtain an acrylic pressure-sensitive adhesive film.

[0047] Specifically, the release layer is made of PE release paper, the substrate layer is made of a TPU film with a thickness of 100 to 200 μm, and the thickness of the adhesive layer is 23 to 27 μm.

[0048] The present invention is further described in detail below in conjunction with specific embodiments.

[0049] In the present invention, isooctyl acrylate was purchased from Formosa Plastics Industry (Ningbo), n-butyl acrylate was purchased from BASF-YPC, acrylic acid was purchased from Hebei Satellite Chemical, hydroxyethyl acrylate was purchased from Jiaxing Jinyan Chemical, methyl acrylate was purchased from Hebei Satellite Chemical, methyl methacrylate was purchased from Mitsubishi Chemical, ethyl acetate was purchased from Taixing Jinjiang Chemical, toluene was purchased from Taixing Jinjiang Chemical, n-heptane was purchased from Suzhou Chengxiang Chemical, isopropanol was purchased from Suzhou Chengxiang Chemical, acetone was purchased from Suzhou Chengxiang Chemical, azobisisobutyronitrile was purchased from Shanghai Shisihewei Chemical, acetylacetone was purchased from Shanghai Zhanyun Chemical, and aluminum acetylacetonate was purchased from Shanghai Zhanyun Chemical.

[0050] Example 1

[0051] In parts by weight, 630 parts of isooctyl acrylate, 620 parts of methyl acrylate, 90 parts of acrylic acid, 10 parts of hydroxyethyl acrylate, 5 parts of methyl methacrylate, 1500 parts of ethyl acetate, 180 parts of n-heptane and 40 parts of isopropanol were mixed evenly and added to a reactor, which was kept under a nitrogen protective atmosphere for more than 30 minutes.

[0052] The reactor was heated to 65° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1.5 hours.

[0053] The reactor was then heated to 70° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1 hour.

[0054] The reactor was then heated to 75° C., 3 parts of azobisisobutyronitrile were dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 3 hours.

[0055] The reaction kettle was then cooled to 45° C., 260 parts of isopropanol were added, and after being stirred evenly, the mixture was filtered to obtain an acrylic pressure-sensitive adhesive.

[0056] Example 2

[0057] In parts by weight, 630 parts of n-butyl acrylate, 620 parts of methyl acrylate, 90 parts of acrylic acid, 10 parts of hydroxyethyl acrylate, 5 parts of methyl methacrylate, 1500 parts of ethyl acetate, 180 parts of n-heptane and 40 parts of isopropanol were mixed evenly and added to a reactor, which was kept under a nitrogen protective atmosphere for more than 30 minutes.

[0058] The reactor was heated to 65° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1.5 hours.

[0059] The reactor was then heated to 70° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1 hour.

[0060] The reactor was then heated to 75° C., 3 parts of azobisisobutyronitrile were dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 3 hours.

[0061] The reaction kettle was then cooled to 45° C., 260 parts of isopropanol were added, and after being stirred evenly, the mixture was filtered to obtain an acrylic pressure-sensitive adhesive.

[0062] Example 3

[0063] In parts by weight, 630 parts of isooctyl acrylate, 620 parts of n-butyl acrylate, 90 parts of acrylic acid, 10 parts of hydroxyethyl acrylate, 5 parts of methyl methacrylate, 1500 parts of ethyl acetate, 180 parts of n-heptane and 40 parts of isopropanol were mixed evenly and added to a reactor, which was kept under a nitrogen protective atmosphere for more than 30 minutes.

[0064] The reactor was heated to 65° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1.5 hours.

[0065] The reactor was then heated to 70° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1 hour.

[0066] The reactor was then heated to 75° C., 3 parts of azobisisobutyronitrile were dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 3 hours.

[0067] The reaction kettle was then cooled to 45° C., 260 parts of isopropanol were added, and after being stirred evenly, the mixture was filtered to obtain an acrylic pressure-sensitive adhesive.

[0068] Example 4

[0069] In parts by weight, 630 parts of isooctyl acrylate, 620 parts of methyl acrylate, 90 parts of acrylic acid, 10 parts of hydroxyethyl acrylate, 5 parts of methyl methacrylate, 1500 parts of ethyl acetate, 180 parts of n-heptane and 30 parts of isopropanol were mixed evenly and added to a reactor, which was kept under a nitrogen protective atmosphere for more than 30 minutes.

[0070] The reactor was heated to 65° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1.5 hours.

[0071] The reactor was then heated to 70° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1 hour.

[0072] The reactor was then heated to 75° C., 3 parts of azobisisobutyronitrile were dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 3 hours.

[0073] The reaction kettle was then cooled to 45° C., 260 parts of isopropanol were added, and after being stirred evenly, the mixture was filtered to obtain an acrylic pressure-sensitive adhesive.

[0074] Example 5

[0075] In parts by weight, 630 parts of isooctyl acrylate, 620 parts of methyl acrylate, 90 parts of acrylic acid, 10 parts of hydroxyethyl acrylate, 5 parts of methyl methacrylate, 1500 parts of ethyl acetate, 180 parts of n-heptane and 50 parts of isopropanol were mixed evenly and added to a reactor, which was kept under a nitrogen protective atmosphere for more than 30 minutes.

[0076] The reactor was heated to 65° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1.5 hours.

[0077] The reactor was then heated to 70° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1 hour.

[0078] The reactor was then heated to 75° C., 3 parts of azobisisobutyronitrile were dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 3 hours.

[0079] The reaction kettle was then cooled to 45° C., 260 parts of isopropanol were added, and after being stirred evenly, the mixture was filtered to obtain an acrylic pressure-sensitive adhesive.

[0080] Example 6

[0081] In parts by weight, 630 parts of isooctyl acrylate, 620 parts of methyl acrylate, 90 parts of acrylic acid, 10 parts of hydroxyethyl acrylate, 5 parts of methyl methacrylate, 1500 parts of ethyl acetate, 180 parts of n-heptane and 160 parts of isopropanol were mixed evenly and added to a reactor, which was kept under a nitrogen protective atmosphere for more than 30 minutes.

[0082] The reactor was heated to 65° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1.5 hours.

[0083] The reactor was then heated to 70° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1 hour.

[0084] The reactor was then heated to 75° C., 3 parts of azobisisobutyronitrile were dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 3 hours.

[0085] The reaction kettle was then cooled to 45° C., 260 parts of isopropanol were added, and after being stirred evenly, the mixture was filtered to obtain an acrylic pressure-sensitive adhesive.

[0086] Example 7

[0087] In parts by weight, 630 parts of isooctyl acrylate, 620 parts of methyl acrylate, 90 parts of acrylic acid, 10 parts of hydroxyethyl acrylate, 5 parts of methyl methacrylate, 1500 parts of ethyl acetate, 180 parts of n-heptane and 40 parts of isopropanol were mixed evenly and added to a reactor, which was kept under a nitrogen protective atmosphere for more than 30 minutes.

[0088] The reactor was heated to 65° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1.5 hours.

[0089] The reactor was then heated to 70° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1 hour.

[0090] The reactor was then heated to 75° C., 3 parts of azobisisobutyronitrile were dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 3 hours.

[0091] The reaction kettle was then cooled to 45° C., 260 parts of isopropanol and 2000 parts of ethyl acetate were added, stirred evenly, and filtered to obtain an acrylic pressure-sensitive adhesive.

[0092] Example 8

[0093] In parts by weight, 630 parts of isooctyl acrylate, 620 parts of methyl acrylate, 90 parts of acrylic acid, 10 parts of hydroxyethyl acrylate, 5 parts of methyl methacrylate, 1300 parts of ethyl acetate, 180 parts of n-heptane, 200 parts of acetone and 40 parts of isopropanol were mixed evenly and added to a reactor, and kept under a nitrogen protective atmosphere for more than 30 minutes.

[0094] The reactor was heated to 65° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1.5 hours.

[0095] The reactor was then heated to 70° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1 hour.

[0096] The reactor was then heated to 75° C., 3 parts of azobisisobutyronitrile were dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 3 hours.

[0097] The reaction kettle was then cooled to 45° C., 260 parts of isopropanol were added, and after being stirred evenly, the mixture was filtered to obtain an acrylic pressure-sensitive adhesive.

[0098] Comparative Example 1

[0099] In parts by weight, 630 parts of isooctyl acrylate, 620 parts of methyl acrylate, 90 parts of acrylic acid, 10 parts of hydroxyethyl acrylate, 5 parts of methyl methacrylate, 1300 parts of ethyl acetate, 180 parts of n-heptane, 200 parts of toluene and 40 parts of isopropanol were mixed evenly and added to a reactor, which was kept under a nitrogen protective atmosphere for more than 30 minutes.

[0100] The reactor was heated to 65° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1.5 hours.

[0101] The reactor was then heated to 70° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1 hour.

[0102] The reactor was then heated to 75° C., 3 parts of azobisisobutyronitrile were dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 3 hours.

[0103] The reaction kettle was then cooled to 45° C., 260 parts of isopropanol were added, and after being stirred evenly, the mixture was filtered to obtain an acrylic pressure-sensitive adhesive.

[0104] Comparative Example 2

[0105] In parts by weight, 630 parts of isooctyl acrylate, 620 parts of methyl acrylate, 90 parts of acrylic acid, 10 parts of hydroxyethyl acrylate, 5 parts of methyl methacrylate, 1300 parts of ethyl acetate, 180 parts of n-heptane and 500 parts of toluene were mixed evenly and added to a reactor, which was kept under a nitrogen protective atmosphere for more than 30 minutes.

[0106] The reactor was heated to 65° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1.5 hours.

[0107] The reactor was then heated to 70° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1 hour.

[0108] The reactor was then heated to 75° C., 3 parts of azobisisobutyronitrile were dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 3 hours.

[0109] The reaction kettle was then cooled to 45° C., 260 parts of isopropanol were added, and after being stirred evenly, the mixture was filtered to obtain an acrylic pressure-sensitive adhesive.

[0110] Comparative Example 3

[0111] In parts by weight, 630 parts of isooctyl acrylate, 620 parts of methyl acrylate, 90 parts of acrylic acid, 5 parts of methyl methacrylate, 1500 parts of ethyl acetate, 180 parts of n-heptane and 40 parts of isopropanol were mixed evenly and added to a reactor, which was kept under a nitrogen protective atmosphere for more than 30 minutes.

[0112] The reactor was heated to 65° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1.5 hours.

[0113] The reactor was then heated to 70° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1 hour.

[0114] The reactor was then heated to 75° C., 3 parts of azobisisobutyronitrile were dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 3 hours.

[0115] The reaction kettle was then cooled to 45° C., 260 parts of isopropanol were added, and after being stirred evenly, the mixture was filtered to obtain an acrylic pressure-sensitive adhesive.

[0116] Comparative Example 4

[0117] In parts by weight, 630 parts of isooctyl acrylate, 620 parts of methyl acrylate, 90 parts of acrylic acid, 10 parts of hydroxyethyl acrylate, 1500 parts of ethyl acetate, 180 parts of n-heptane and 40 parts of isopropanol were mixed evenly and added to a reactor, which was kept under a nitrogen protective atmosphere for more than 30 minutes.

[0118] The reactor was heated to 65° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1.5 hours.

[0119] The reactor was then heated to 70° C., 1 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 1 hour.

[0120] The reactor was then heated to 75° C., 3 parts of azobisisobutyronitrile were dissolved in 10 parts of ethyl acetate, and then added into the reactor to react for 3 hours.

[0121] The reaction kettle was then cooled to 45° C., 260 parts of isopropanol were added, and after being stirred evenly, the mixture was filtered to obtain an acrylic pressure-sensitive adhesive.

[0122] The acrylate pressure-sensitive adhesives in the examples and comparative examples were respectively used to prepare acrylate pressure-sensitive adhesive films, which were prepared as follows: 100 g of acrylate pressure-sensitive adhesive was taken, 0.15 g of aluminum acetylacetonate and 0.5 g of acetylacetone were added thereto, and the mixture was stirred evenly to obtain a sizing material. The sizing material was coated on a 100 μm PE release paper with a coating rod, dried and cured at 90° C. for 3 min to form an adhesive layer, and a 150 μm thick TPU film was compounded on the adhesive layer to obtain an acrylate pressure-sensitive adhesive film.

[0123] The following tests were performed on the acrylate pressure-sensitive adhesive and acrylate pressure-sensitive adhesive film in each embodiment and comparative example:

[0124] (1) Molecular weight and molecular weight distribution: Gel permeation chromatograph Agilent 1260 Infinity, test standard GB / T21863-2008

[0125] (2) 180° peel strength test: Determined according to GB 2792-1998 180° peel strength test method for pressure-sensitive adhesive tapes.

[0126] Table 1 Performance test results

[0127]

[0128]

[0129] Combined with Table 1, toluene was used as a solvent in Comparative Examples 1 and 2, and the obtained acrylic pressure-sensitive adhesive had a high viscosity, especially Comparative Example 2, which had a high viscosity and molecular weight and was not applicable, and the peeling force performance of Comparative Example 1 was relatively poor, indicating that using different solvents in combination with the present invention can help obtain an acrylic pressure-sensitive adhesive with excellent performance.

[0130] In Comparative Examples 3 and 4, the functional monomer and (meth) acrylic hard monomer B were removed, and the obtained acrylate pressure-sensitive adhesives had poor performance relative to the examples. Although the viscosity was appropriate, the peel force was low, and the overall performance was worse than that of the examples. This shows that the use of a variety of monomers in combination with the present invention can improve the performance of the acrylate pressure-sensitive adhesive, and it is not easy to fall off during specific use and has stable performance.

[0131] 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.

[0132] 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. An acrylic pressure-sensitive adhesive, characterized in that: The invention comprises the following raw materials in parts by weight: 500-900 parts of (meth) acrylic acid soft monomer, 400-800 parts of (meth) acrylic acid hard monomer A, 80-100 parts of acrylic acid, 5-15 parts of (meth) acrylic acid functional monomer, 1-10 parts of (meth) acrylic acid hard monomer B, 1800-4200 parts of solvent, and 5-10 parts of initiator; The solvent is selected from the group consisting of n-hexane, cyclohexane, n-heptane, acetone and isopropanol.

2. The acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The (meth) acrylic soft monomer is one or more of isooctyl (meth) acrylate, butyl (meth) acrylate, and ethyl (meth) acrylate.

3. The acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The (meth)acrylic hard monomer A is one or more of methyl (meth)acrylate, isobornyl (meth)acrylate, and cyclohexyl (meth)acrylate.

4. The acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The (meth)acrylic hard monomer B is one or more of methyl (meth)acrylate, isobornyl (meth)acrylate, and cyclohexyl (meth)acrylate.

5. The acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The (meth) acrylic acid functional monomer contains -COOH, -OH, amide group or unsaturated double bond group.

6. The acrylic pressure-sensitive adhesive according to claim 5, characterized in that: The (meth)acrylic functional monomer is one or more of hydroxyethyl (meth)acrylate, hydroxybutyl (meth)acrylate, acrylamide, N-vinyl caprolactam, acrylonitrile, N-vinyl pyrrolidone, (meth)acrylic acid, 2-carboxyethyl acrylate and 4-hydroxyvinyloxybenzophenone methacrylate.

7. The acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The initiator is one or both of azobisisobutyronitrile and dibenzoyl peroxide.

8. A method for preparing the acrylic pressure-sensitive adhesive according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1, taking (meth) acrylic acid soft monomer, (meth) acrylic acid hard monomer A, acrylic acid, (meth) acrylic acid functional monomer, (meth) acrylic acid hard monomer B and 1500-2000 parts by weight of solvent, mixing and adding into a reaction container, and keeping under a protective gas atmosphere; Step 2, raising the temperature to 65-67° C., dissolving 1-2 parts by weight of an initiator in 10-20 parts by weight of a solvent, adding the mixture to a reaction vessel, and reacting for 1.2-1.8 hours; Step 3, heating to 70-73°C, dissolving 1-2 parts by weight of initiator in 10-20 parts by weight of solvent, adding to the reaction vessel, and reacting for 0.8-1.2h; Step 4, heating to 75-78°C, dissolving the remaining initiator in part of the solvent, adding the mixture to the reaction vessel, and reacting for 2.8-3.2h; Step 5, cooling to 45-55° C., adding the remaining solvent, and stirring evenly to obtain an acrylic pressure-sensitive adhesive.

9. An acrylic pressure-sensitive adhesive film, characterized in that: The invention comprises a substrate layer, an adhesive layer and a release layer which are stacked in sequence, wherein the raw materials of the adhesive layer comprise 100 parts by weight of an acrylic pressure-sensitive adhesive, 0.13 to 0.18 parts by weight of a cross-linking agent and 0.4 to 0.6 parts by weight of a protective agent; Wherein, the acrylic pressure-sensitive adhesive is the acrylic pressure-sensitive adhesive according to any one of claims 1 to 7.

10. A method for preparing the acrylic pressure-sensitive adhesive film according to claim 9, characterized in that: The steps include: Mixing an acrylic pressure-sensitive adhesive, a cross-linking agent and a protective agent to obtain a rubber compound; Apply the adhesive on the release layer and heat at 90-110°C for 3-5 minutes to form an adhesive layer; A substrate layer is compounded on the adhesive layer to obtain an acrylic pressure-sensitive adhesive film.

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