Preparation method of hydrophilic acrylic pressure-sensitive adhesive and adhesive tape prepared from hydrophilic acrylic pressure-sensitive adhesive

Abstract

The invention provides a preparation method of a hydrophilic acrylic pressure-sensitive adhesive and an adhesive tape prepared from the hydrophilic acrylic pressure-sensitive adhesive, and the preparation method comprises the following steps: S1, sequentially adding a reaction monomer and an initiator into a solvent for copolymerization to obtain an acrylate adhesive; and S2, coating the surface of a base material with an acrylate adhesive, and drying at 80-120 DEG C to obtain the hydrophilic acrylic pressure-sensitive adhesive tape. The reaction monomer is prepared from the following components in parts by weight: 10 to 30 parts of 2-ethylhexyl acrylate, 10 to 20 parts of 2-hydroxyethyl acrylate, 3 to 15 parts of acrylic acid, 15 to 30 parts of N-vinyl pyrrolidone, 10 to 25 parts of polyethylene glycol acrylate monomer, 2 to 10 parts of amino acrylate monomer, 0.2 to 1 part of initiator and 100 to 250 parts of solvent. According to the hydrophilic acrylic pressure-sensitive adhesive tape, monomers with a large number of polar groups are introduced and are combined with water molecules through hydrogen bonds or ion interaction, and the hydrophilic performance of the acrylic pressure-sensitive adhesive tape is remarkably improved.

Description

Technical Field

[0001] This invention relates to an acrylic pressure-sensitive adhesive, specifically a method for preparing a hydrophilic acrylic pressure-sensitive adhesive and the tape made therefrom. Background Technology

[0002] Hydrophilic acrylic pressure-sensitive adhesives are a type of functionalized adhesive developed from traditional acrylic pressure-sensitive adhesives. By introducing hydrophilic groups or components, they endow materials with moisture-absorbing, moisture-permeable, or water-compatible properties. Due to their excellent adhesion, water resistance, biocompatibility, and controllable adhesion, they are widely used in various industries. However, different industries have imposed stringent requirements on their performance, safety, and environmental friendliness. In the medical and health field, biocompatibility and safety are particularly important, including cytotoxicity, sensitization, irritation, and long-term implantation testing to ensure the safety of materials in contact with the human body. Allergic reactions caused by residual monomers must be avoided, while also meeting the moisture permeability requirements of medical dressings. Industry requirements for hydrophilic acrylic pressure-sensitive adhesives cover biosafety, environmental tolerance, environmental compliance, and functionality, and are constantly being upgraded with technological advancements and regulatory updates, thus placing even higher demands on hydrophilic acrylic pressure-sensitive adhesive tapes and their performance. Summary of the Invention

[0003] The purpose of this invention is to overcome the above-mentioned deficiencies in the prior art and to provide a method for preparing a hydrophilic acrylic pressure-sensitive adhesive and the adhesive tape made therefrom.

[0004] The technical solution adopted by this invention to solve the above problems is: a method for preparing a hydrophilic acrylic pressure-sensitive adhesive, comprising the following steps: The reactive monomers and initiators are added sequentially to the solvent for copolymerization to obtain an acrylate adhesive. The reactive monomer comprises the following components, by weight, including the following raw materials: 10-30 parts isooctyl acrylate, 10-20 parts acrylic acid. 2 Hydroxyethyl ester, 3-15 parts acrylic acid, 15-30 parts N-vinylpyrrolidone, 10-25 parts polyethylene glycol acrylate monomers, 2-10 parts acrylate amino ester monomers, 0.2-1 parts initiator, and 100-250 parts solvent.

[0005] The polyethylene glycol acrylate monomers include one or more of methoxy polyethylene glycol acrylate, methoxy polyethylene glycol methacrylate, polyethylene glycol methacrylate, polyethylene glycol diacrylate, and ethoxy polyethylene glycol methacrylate.

[0006] Preferably, it is methoxy polyethylene glycol methacrylate or / and polyethylene glycol methacrylate; more preferably, the average number n of oxyethylene groups in the polyethylene glycol is 8 to 25.

[0007] The acrylate amino ester monomers include one or more of dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl acrylate, and dimethylaminopropyl acrylate.

[0008] Preferably, it is dimethylaminoethyl methacrylate or / and dimethylaminoethyl acrylate.

[0009] The initiator is one or more of benzoyl peroxide, azobisisobutyronitrile, azobisisoheptanenitrile, and dimethyl azobisisobutyrate.

[0010] Preferably, it is benzoyl peroxide and / or azobisisobutyronitrile.

[0011] The solvent in the acrylate adhesive is one or more of benzene, ester, and ketone compounds.

[0012] Preferably, it is one or more of toluene, ethyl acetate, butyl acetate, and acetone; more preferably, it is ethyl acetate and / or butyl acetate.

[0013] The copolymerization process employs a stepwise dropwise addition method, specifically including the following two steps: Step 1: Under nitrogen atmosphere, take a portion of the reactant monomer, the first part of the initiator and half of the solvent and add them to a four-necked flask. Control the temperature at 70-85℃ and react for 60-100 minutes. Step 2: Mix the remaining reactant monomers, the second part of the initiator, and the other half of the solvent evenly, and then add them dropwise to a four-necked flask over a period of 90 to 120 minutes; control the temperature at 70 to 85°C and react for 4 to 6 hours; after the reaction is complete, cool down to 50°C, adjust the solid content, and obtain the acrylate adhesive.

[0014] The proportions of monomers, initiators, and solvents added in steps one and two are calculated based on the total amount of solvents required in all steps of preparing the hydrophilic acrylic pressure-sensitive adhesive. A hydrophilic acrylic pressure-sensitive tape is obtained by coating an acrylic adhesive onto the surface of a substrate and drying it at 80–120°C.

[0015] Preferably, the tape comprises a release film layer and a hydrophilic adhesive layer stacked in sequence, wherein the hydrophilic adhesive layer is obtained by coating, drying, and cross-linking the above-mentioned acrylic pressure-sensitive adhesive in one step and curing in a second step.

[0016] Preferably, the release force of the release film is 5-10 gf / in, the thickness of the release film is 25-50 μm, and the thickness of the hydrophilic adhesive layer is 25-50 μm.

[0017] Preferably, the hydrophilic adhesive layer is formed by coating an acrylic pressure-sensitive adhesive onto a PET substrate that has not undergone inert treatment, drying it to form a hydrophilic adhesive layer, then bonding the hydrophilic adhesive layer onto a release film, and finally curing it in an oven to obtain a hydrophilic acrylic pressure-sensitive tape.

[0018] Preferably, the thickness of the PET substrate is 50-100 μm, the drying conditions are 80-120℃ for 3-5 minutes, the curing conditions are 35-60℃ for 2-3 days, and the winding method is to wind with the release film side facing inward.

[0019] Compared with the prior art, the present invention has the following advantages and effects: 1. This invention utilizes monomer copolymerization to prepare a hydrophilic acrylic pressure-sensitive tape by introducing specific components and proportions of reactive monomers; and by regulating the efficient interaction between the polar groups in these monomers and water, while further optimizing the hydrophilic properties through the flexibility and spatial arrangement of the molecular structure. By selecting different types of monomers or copolymer combinations, the hydrophilicity and functional applications of the pressure-sensitive adhesive can be precisely controlled.

[0020] 2. Among them, isooctyl acrylate is used as the reactant monomer. Since isooctyl acrylate is a soft monomer with a relatively long alkyl chain, it has good cohesiveness and provides a certain degree of adhesion. At the same time, the hydroxyl group in 2-hydroxyethyl acrylate and the polar carbonyl group in N-vinylpyrrolidone can act as hydrogen bond acceptors to form multiple hydrogen bonds with water molecules, which significantly improves hydrophilicity.

[0021] 3. The introduction of polyethylene glycol acrylate monomers, where polyethylene glycol segments consist of repeating ether bonds, allows each oxygen atom to act as a hydrogen bond acceptor, forming a dense hydrogen bond network with water molecules and enhancing hydrophilicity. Simultaneously, the long-chain polyethylene glycol can encapsulate a large number of water molecules, forming a hydration layer that significantly improves solubility and resistance to dehydration. Furthermore, the introduction of amino acrylate monomers gives it excellent pH responsiveness; under acidic and neutral conditions, it can form cations through protonation, strongly binding with water molecules.

[0022] 4. This hydrophilic acrylic pressure-sensitive tape incorporates a large number of monomers containing polar groups, which bind to water molecules through hydrogen bonds or ionic interactions, significantly improving the hydrophilic properties of the acrylic pressure-sensitive tape. Attached Figure Description

[0023] Figure 1 This is a comparison diagram of the contact angles of the hydrophilic acrylic pressure-sensitive tapes obtained in Examples 1-5 and Comparative Examples 1-3. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0025] In the embodiments, all the following quantities are parts by weight.

[0026] Example 1: The hydrophilic acrylic pressure-sensitive adhesive formulation of this embodiment is as follows: 10 parts isooctyl acrylate, 23 parts 2-hydroxyethyl acrylate, 5 parts acrylic acid, 30 parts N-vinylpyrrolidone, 25 parts methoxy polyethylene glycol acrylate, 7 parts dimethylaminoethyl methacrylate, 200 parts ethyl acetate; and 0.4 wt% of azobisisobutyronitrile as an initiator. The method for manufacturing the hydrophilic acrylic pressure-sensitive tape in this embodiment includes the following steps: (1) Take 40 wt% of the reactant monomer, 0.2 wt% of azobisisobutyronitrile and 50 wt% of ethyl acetate and add them to a four-necked flask. Control the temperature at 75℃ and react for 1 hour. Mix the remaining 60 wt% of the reactant monomer, 0.2 wt% of azobisisobutyronitrile and 50 wt% of ethyl acetate evenly and add them to a dropping funnel. Add them to the reaction system dropwise over 100 minutes. After the addition is complete, control the temperature at 75℃ and keep it at that temperature for 4 hours. Cool down to below 50℃ to obtain the adhesive for later use.

[0027] (2) The pressure-sensitive adhesive obtained in step (1) is coated on a 50μm PET substrate that has not undergone inert treatment, and then baked at 80℃ for 5 minutes to form a pressure-sensitive adhesive layer. The thickness of the dry adhesive film is controlled to be 25±1μm. All are covered with a 50μm PET release film, and then cured in a 40℃ oven for 48 hours to obtain a hydrophilic acrylic pressure-sensitive tape.

[0028] Example 2: The hydrophilic acrylic pressure-sensitive adhesive formulation of this embodiment is as follows: 15 parts isooctyl acrylate, 20 parts 2-hydroxyethyl acrylate, 10 parts acrylic acid, 30 parts N-vinylpyrrolidone, 20 parts methoxy polyethylene glycol acrylate, 5 parts dimethylaminoethyl methacrylate, and 230 parts ethyl acetate; 0.8 wt% of azobisisobutyronitrile is used as an initiator. The method for manufacturing the hydrophilic acrylic pressure-sensitive tape in this embodiment includes the following steps: (1) Take 40 wt% of the reactant monomer, 0.2 wt% of azobisisobutyronitrile and 50 wt% of ethyl acetate and add them to a four-necked flask. Control the temperature at 75℃ and react for 1 hour. Mix the remaining 60 wt% of the reactant monomer, 0.2 wt% of azobisisobutyronitrile and 50 wt% of ethyl acetate evenly and add them to a dropping funnel. Add them to the reaction system dropwise over 100 minutes. After the addition is complete, control the temperature at 75℃ and keep it at that temperature for 4 hours. Cool down to below 50℃ to obtain the adhesive for later use.

[0029] (2) The pressure-sensitive adhesive obtained in step (1) is coated on a 50μm PET substrate that has not undergone inert treatment, and then baked at 80℃ for 5 minutes to form a pressure-sensitive adhesive layer. The thickness of the dry adhesive film is controlled to be 25±1μm. All are covered with a 50μm PET release film, and then cured in a 40℃ oven for 48 hours to obtain a hydrophilic acrylic pressure-sensitive tape.

[0030] Example 3: The hydrophilic acrylic pressure-sensitive adhesive formulation of this embodiment is as follows: 20 parts isooctyl acrylate, 27 parts 2-hydroxyethyl acrylate, 8 parts acrylic acid, 20 parts N-vinylpyrrolidone, 20 parts methoxy polyethylene glycol methacrylate, 5 parts diethylaminoethyl methacrylate, 150 parts ethyl acetate; and 0.4 wt% of azobisisobutyronitrile as an initiator. The method for manufacturing the hydrophilic acrylic pressure-sensitive tape in this embodiment includes the following steps: (1) Take 40 wt% of the reactant monomer, 0.2 wt% of azobisisobutyronitrile and 50 wt% of ethyl acetate and add them to a four-necked flask. Control the temperature at 75℃ and react for 1 hour. Mix the remaining 60 wt% of the reactant monomer, 0.2 wt% of azobisisobutyronitrile and 50 wt% of ethyl acetate evenly and add them to a dropping funnel. Add them to the reaction system dropwise over 100 minutes. After the addition is complete, control the temperature at 75℃ and keep it at that temperature for 4 hours. Cool down to below 50℃ to obtain the adhesive for later use.

[0031] (2) The pressure-sensitive adhesive obtained in step (1) is coated on a 50μm PET substrate that has not undergone inert treatment, and then baked at 80℃ for 5 minutes to form a pressure-sensitive adhesive layer. The thickness of the dry adhesive film is controlled to be 25±1μm. All are covered with a 50μm PET release film, and then cured in a 40℃ oven for 48 hours to obtain a hydrophilic acrylic pressure-sensitive tape.

[0032] Example 4: The hydrophilic acrylic pressure-sensitive adhesive formulation of this embodiment is as follows: 20 parts isooctyl acrylate, 25 parts 2-hydroxyethyl acrylate, 8 parts acrylic acid, 25 parts N-vinylpyrrolidone, 20 parts polyethylene glycol methacrylate, 2 parts dimethylaminoethyl acrylate, 180 parts ethyl acetate; and 0.5 wt% of azobisisobutyronitrile as an initiator. The method for manufacturing the hydrophilic acrylic pressure-sensitive tape in this embodiment includes the following steps: (1) Take 40 wt% of the reactant monomer, 0.2 wt% of azobisisobutyronitrile and 50 wt% of ethyl acetate and add them to a four-necked flask. Control the temperature at 80℃ and react for 1 hour. Mix the remaining 60 wt% of the reactant monomer, 0.2 wt% of azobisisobutyronitrile and 50 wt% of ethyl acetate evenly and add them to a dropping funnel. Add them to the reaction system dropwise over 100 minutes. After the addition is complete, control the temperature at 80℃ and keep it at that temperature for 4 hours. Cool down to below 50℃ to obtain the adhesive for later use.

[0033] (2) The pressure-sensitive adhesive obtained in step (1) is coated on a 50μm PET substrate that has not undergone inert treatment, and then baked at 80℃ for 5 minutes to form a pressure-sensitive adhesive layer. The thickness of the dry adhesive film is controlled to be 25±1μm. All are covered with a 50μm PET release film, and then cured in a 40℃ oven for 48 hours to obtain a hydrophilic acrylic pressure-sensitive tape.

[0034] Example 5: The hydrophilic acrylic pressure-sensitive adhesive formulation of this embodiment is as follows: 25 parts isooctyl acrylate, 10 parts 2-hydroxyethyl acrylate, 5 parts acrylic acid, 30 parts N-vinylpyrrolidone, 25 parts methoxy polyethylene glycol methacrylate, 5 parts dimethylaminoethyl acrylate, 150 parts ethyl acetate; and 0.4 wt% azobisisobutyronitrile as an initiator. The method for manufacturing the hydrophilic acrylic pressure-sensitive tape in this embodiment includes the following steps: (1) Take 40 wt% of the reactant monomer, 0.2 wt% of azobisisobutyronitrile and 50 wt% of ethyl acetate and add them to a four-necked flask. Control the temperature at 80℃ and react for 1 hour. Mix the remaining 60 wt% of the reactant monomer, 0.2 wt% of azobisisobutyronitrile and 50 wt% of ethyl acetate evenly and add them to a dropping funnel. Add them to the reaction system dropwise over 100 minutes. After the addition is complete, control the temperature at 80℃ and keep it at that temperature for 4 hours. Cool down to below 50℃ to obtain the adhesive for later use.

[0035] (2) The pressure-sensitive adhesive obtained in step (1) is coated on a 50μm PET substrate that has not undergone inert treatment, and then baked at 80℃ for 5 minutes to form a pressure-sensitive adhesive layer. The thickness of the dry adhesive film is controlled to be 25±1μm. All are covered with a 50μm PET release film, and then cured in a 40℃ oven for 48 hours to obtain a hydrophilic acrylic pressure-sensitive tape.

[0036] Comparative Example 1: Compared with Example 1, everything else was the same except that N-vinylpyrrolidone monomer was not added to the formulation; Comparative Example 2: Compared with Example 1, except that polyethylene glycol acrylate monomers were not added to the formulation, everything else was the same; Comparative Example 3: Compared with Example 1, it is the same in all aspects except that no acrylate amino ester monomers are added to the formulation; Experiment: The hydrophilic acrylic pressure-sensitive tapes prepared in Examples 1-5 and Comparative Examples 1-3 were subjected to performance tests as follows.

[0037] 1. Use a contact angle tester to test the contact angle of the pressure-sensitive tape.

[0038] 2. The 180° peel strength of the pressure-sensitive tape prepared above shall be tested in accordance with GB / T2792.

[0039] The test results are shown in the table below:

[0040] Conclusion: As shown in the table, this invention has prepared an acrylic pressure-sensitive tape with excellent hydrophilic properties. Data from Comparative Examples 1-3 indicate that the introduction of a large number of monomers containing polar groups significantly reduces the contact angle of the adhesive film, thus significantly improving the hydrophilic properties of the acrylic pressure-sensitive tape. Examples 1-5 prepared according to the technical solution provided by this invention exhibit excellent hydrophilicity and good adhesive properties.

[0041] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a hydrophilic acrylic pressure-sensitive adhesive, comprising the following steps: The reactive monomers and initiators are added sequentially to the solvent for copolymerization to obtain an acrylate adhesive. The reactive monomer comprises the following components, by weight, including the following raw materials: 10-30 parts isooctyl acrylate, 10-20 parts acrylic acid. 2 Hydroxyethyl ester, 3-15 parts acrylic acid, 15-30 parts N-vinylpyrrolidone, 10-25 parts polyethylene glycol acrylate monomers, 2-10 parts acrylate amino ester monomers, 0.2-1 parts initiator, and 100-250 parts solvent.

2. The method for preparing the hydrophilic acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The polyethylene glycol acrylate monomers include one or more of methoxy polyethylene glycol acrylate, methoxy polyethylene glycol methacrylate, polyethylene glycol methacrylate, polyethylene glycol diacrylate, and ethoxy polyethylene glycol methacrylate.

3. The method for preparing the hydrophilic acrylic pressure-sensitive adhesive according to claim 2, characterized in that: The polyethylene glycol acrylate monomers are methoxy polyethylene glycol methacrylate and / or polyethylene glycol methacrylate, and the average number n of oxyethylene groups in the polyethylene glycol is 8 to 25.

4. The method for preparing the hydrophilic acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The acrylate amino ester monomers include one or more of dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl acrylate, and dimethylaminopropyl acrylate.

5. The method for preparing the hydrophilic acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The initiator is one or more of benzoyl peroxide, azobisisobutyronitrile, azobisisoheptanenitrile, and dimethyl azobisisobutyrate.

6. The method for preparing the hydrophilic acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The solvent of the acrylate adhesive is one or more of benzene, ester, and ketone compounds, preferably one or more of toluene, ethyl acetate, butyl acetate, and acetone.

7. The method for preparing the hydrophilic acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The preparation of the acrylate adhesive includes the following steps: Step 1: Under nitrogen atmosphere, take a portion of the reactant monomer, the first part of the initiator and half of the solvent and add them to a four-necked flask. Control the temperature at 70-85℃ and react for 60-100 minutes. Step 2: Mix the remaining reactant monomers, the second part of the initiator, and the other half of the solvent evenly, and then add them dropwise to a four-necked flask over a period of 90 to 120 minutes; control the temperature at 70 to 85°C and react for 4 to 6 hours; after the reaction is complete, cool down to 50°C, adjust the solid content, and obtain the acrylate adhesive.

8. A hydrophilic acrylic pressure-sensitive tape, characterized in that: An acrylic adhesive prepared by any one of claims 1-8 is coated onto the surface of a substrate and dried to obtain a hydrophilic acrylic pressure-sensitive tape.

9. The hydrophilic acrylic pressure-sensitive tape according to claim 8, characterized in that: The hydrophilic acrylic pressure-sensitive tape comprises, in sequence, a release film layer and a hydrophilic adhesive layer, wherein the hydrophilic adhesive layer is prepared by coating, drying, crosslinking once, and curing, crosslinking twice from the above-mentioned acrylic pressure-sensitive adhesive.

10. The hydrophilic acrylic pressure-sensitive tape according to claim 9, characterized in that: The hydrophilic adhesive layer is formed by coating an acrylic pressure-sensitive adhesive onto a PET substrate that has not undergone inert treatment, drying it to form a hydrophilic adhesive layer, then bonding the hydrophilic adhesive layer onto a release film, and finally curing it in an oven to obtain a hydrophilic acrylic pressure-sensitive tape. The drying conditions are 80-120℃ for 3-5 minutes, and the curing conditions are 35-60℃ for 2-3 days.

Images