Acrylic acid pressure-sensitive adhesive applied to low-odor low-VOC (volatile organic compound) material and preparation method of acrylic acid pressure-sensitive adhesive

Abstract

The invention belongs to the technical field of acrylic pressure-sensitive adhesives, and provides an acrylic pressure-sensitive adhesive applied to a low-odor and low-VOC (volatile organic compound) material and a preparation method of the acrylic pressure-sensitive adhesive. Comprising the following raw materials: 60-75 parts of a soft monomer, 8-13 parts of a hard monomer, 3-6 parts of a functional monomer, 18-32 parts of tackifying resin, 110-180 parts of a solvent, 5-8 parts of modified nano silicon dioxide, 1-3 parts of an initiator, 2-4 parts of a cross-linking agent and 0.1-1 part of an antioxidant. The low-odor and low-VOC environment-friendly acrylic pressure-sensitive adhesive provided by the invention has the characteristics of low odor, low VOC and the like, is beneficial to guaranteeing the health and safety of sizing personnel, meets the green and environment-friendly production requirements, also has better peel strength and impact strength, is suitable for being applied to the fields of coatings, adhesives, automotive interiors and the like, and has wide application prospects. Wide application prospects are realized.

Description

Technical Field

[0001] This invention belongs to the field of acrylic pressure-sensitive adhesive technology, specifically relating to an acrylic pressure-sensitive adhesive used in low-odor, low-VOC materials and its preparation method. Background Technology

[0002] With increasing demands for environmental protection, health, and safety, low volatile organic compounds (VOCs) and low odor have become key technical indicators for adhesive materials. VOCs refer to organic compounds that easily volatilize at room temperature and are widely found in materials such as coatings, adhesives, and automotive interior materials. Their release can not only cause air pollution inside vehicles, but long-term exposure can also pose potential risks to human health, such as causing discomfort or chronic harm. Therefore, developing low-VOC, low-odor adhesives is an inevitable trend in the development of coatings, adhesives, and automotive interior materials.

[0003] However, in the field of pressure-sensitive adhesives, especially for high-requirement bonding scenarios in automotive interiors, traditional technical approaches have significant limitations. On the one hand, while conventional oil-based acrylic pressure-sensitive adhesives possess excellent adhesion, weather resistance, temperature resistance, and durability, and can pass the stringent environmental tests of the automotive industry (such as high temperature and humidity, thermal cycling, and aging tests), their preparation process often uses large amounts of organic solvents, resulting in a significant amount of residual monomers and by-reaction products. This leads to higher VOC emissions and odor levels in the final tape products, failing to meet in-vehicle air quality standards (such as VDA 278 and ISO 12219). On the other hand, water-based acrylic pressure-sensitive adhesives, using water as the dispersion medium, have certain advantages in terms of VOCs and odor, but their overall performance is often inferior to oil-based systems, particularly in terms of water resistance, high temperature resistance, initial tack, and holding power. This makes it difficult to meet the high-strength environmental testing requirements of automotive interiors, limiting their application in high-end automotive bonding. Patent document US2015 / 0259420A1 describes a water-based acrylic pressure-sensitive adhesive composition with a low VOC content, but acknowledges that its durability under high temperature and high humidity conditions is still inferior to that of oil-based systems.

[0004] It is important to note that odor and VOCs are not directly correlated. Some VOCs have no noticeable odor, while certain non-VOCs containing sulfur, nitrogen, or other heteroatoms can produce strong odors. Therefore, simply reducing odor does not necessarily mean that VOC emissions meet standards, and vice versa. Adhesive tapes used in automotive interiors must achieve synergistic control of both low VOCs and low odors, which places extremely high demands on adhesive formulation design and synthesis processes.

[0005] Therefore, there is an urgent need to develop a pressure-sensitive adhesive solution that can balance high performance and environmental friendliness, possessing the excellent physical properties of oil-based acrylic pressure-sensitive adhesives (such as high bonding strength, temperature resistance, and aging resistance) while significantly reducing VOC emissions and odor levels to meet the stringent standards for materials such as coatings, adhesives, and automotive interiors. Summary of the Invention

[0006] The purpose of this invention is to provide an acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials and its preparation method, so as to solve the technical problems mentioned in the background art.

[0007] The objective of this invention can be achieved through the following technical solutions: The first aspect of this invention provides an acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials, comprising the following raw materials by weight: 60-75 parts soft monomer, 8-13 parts hard monomer, 3-6 parts functional monomer, 18-32 parts tackifying resin, 110-180 parts solvent, 5-8 parts modified nano silica, 1-3 parts initiator, 2-4 parts crosslinking agent, and 0.1-1 parts antioxidant.

[0008] In some embodiments of the present invention, the modified nano-silica is prepared by the following steps: Nano-silica was added to an ethanol-water solution (volume ratio of anhydrous ethanol to deionized water was 3:1), ultrasonically dispersed for 0.5 h, then silane coupling agent KH-570 was added, and ultrasonication was continued for 10-15 min. The pH value was adjusted to 3-4 with glacial acetic acid, and then the temperature was raised to 65-70℃ and stirred for 6-8 h. After the reaction was completed, the mixture was cooled to room temperature and centrifuged. The supernatant was washed with anhydrous ethanol and deionized water until it was neutral. The product was then dried in a vacuum drying oven at 50℃ for 2 h to obtain modified nano-silica.

[0009] In some embodiments of the present invention, the ratio of nano-silica, aqueous ethanol solution and silane coupling agent KH-570 is 2.2-2.5g:80mL:1.6-1.8mL.

[0010] In the above technical solutions, due to the high specific surface area and surface activity of nano-silica, it can be used as a nanofiller for reinforcing and toughening acrylic resins, and can also effectively improve the heat resistance of acrylic resins. However, because the surface of nano-silica particles has a large specific surface area and surface energy, it is prone to agglomeration, which is extremely detrimental to the performance of the nano-effect in polymer modification. Therefore, this invention uses the silane coupling agent KH-570 to chemically modify the surface of nano-silica, grafting allyl functional groups onto its surface, which can then undergo in-situ polymerization with acrylate monomers, thereby effectively improving the dispersion state of nano-silica in polymers and effectively overcoming the agglomeration of nanoparticles.

[0011] In some embodiments of the present invention, the soft monomer is at least one of 2-ethylhexyl acrylate and n-butyl acrylate.

[0012] In some embodiments of the present invention, the hard monomer is at least one of 2-phenoxyethyl methacrylate and tetrahydrofuran methacrylate. Traditional acrylic adhesives commonly use methyl methacrylate as the hard monomer, but it has a low boiling point, high volatility, and releases a strong, pungent odor, becoming a major cause of unpleasant odors and health hazards at work sites. Therefore, to reduce the odor of acrylic adhesives, the present invention selects a low-odor monomer to replace methyl methacrylate, reducing VOCs and odor from the source. 2-phenoxyethyl methacrylate is highly polar, contains a rigid benzene ring, has high hardness, and a high glass transition temperature, acting as a rigid group and skeleton in the copolymer. Tetrahydrofuran methacrylate, on the other hand, has a relatively low glass transition temperature of 60°C, which helps the copolymer maintain good flexibility after curing, significantly improving the impact strength of the adhesive layer and acting as an internal toughening agent. Simultaneously, its tetrahydrofuran and carboxyl groups can form hydrogen bonds with the hydroxyl or oxide groups on the surface of the bonded substrate, thereby greatly increasing the tensile shear strength, adhesion, and toughness of the system.

[0013] In some embodiments of the present invention, the functional monomer is at least one of acrylic acid and hydroxyethyl acrylate.

[0014] In some embodiments of the present invention, the solvent is ethyl acetate; the initiator is one of benzoyl peroxide and azobisisobutyronitrile.

[0015] In some embodiments of the present invention, the tackifying resin is one of hydrogenated terpene resin, hydrogenated C5 petroleum resin, and hydrogenated rosin glycerol ester.

[0016] In some embodiments of the present invention, the crosslinking agent is one of hexamethylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 4,4-dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate trimer; the antioxidant is a hindered phenolic antioxidant; the hindered phenolic antioxidant is one of antioxidant 1010 and antioxidant 1076. Hindered phenolic antioxidants can not only effectively prevent the thermal oxidative degradation of acrylic monomers during processing and use, but also effectively reduce migration and volatilization, improve long-term stability, and thus extend the service life of acrylic pressure-sensitive adhesives.

[0017] A second aspect of this invention provides a method for preparing an acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials, comprising the following steps: Weigh out the components by weight, and under a nitrogen atmosphere, add the soft monomer, hard monomer, functional monomer, and modified nano-silica into a reactor. Heat the reactor to 68-75℃, add 3 / 20 parts by weight of the initiator and 3 / 5 parts by weight of the solvent, and stir for 2-3 hours. Then, add 17 / 20 parts by weight of the initiator and 2 / 5 parts by weight of the solvent, and add them dropwise to the reactor over 3.5-4.0 hours. After the addition is complete, react for 1.5-2.5 hours, then heat the reactor to 90-95℃ and continue the reaction for 1-2 hours. Cool to room temperature and discharge the product to obtain acrylic resin. Then, mix the acrylic resin, tackifying resin, crosslinking agent, and antioxidant obtained above, and stir until homogeneous to obtain acrylic pressure-sensitive adhesive.

[0018] The beneficial effects of this invention are: This invention provides an acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials. By selecting low-volatile hard monomers instead of traditional high-odor methyl methacrylate monomers, it reduces the release of volatile organic compounds and odors at the source, improving the working environment and reducing health risks. Furthermore, this invention abandons the dicumyl peroxide initiator commonly used in traditional processes, preferentially selecting benzoyl peroxide and azobisisobutyronitrile, which are low-odor and have high decomposition efficiency, thus avoiding the introduction of unpleasant odors at the source. This invention also uses low-toxicity solvents and is combined with hydrogenated tackifying resins to further reduce residual odor and toxicity in the system, meeting environmental protection requirements.

[0019] This invention also provides a modified nano-silica, which uses silane coupling agent KH-570 to modify the surface of nano-silica, grafting allyl functional groups onto it, thereby enabling in-situ polymerization with acrylate monomers, effectively inhibiting nanoparticle aggregation, improving its dispersibility in resin, and fully leveraging the reinforcing, toughening, and heat resistance-enhancing effects of nanofillers.

[0020] This invention provides an environmentally friendly acrylic pressure-sensitive adhesive with low odor and low VOC, which helps ensure the health and safety of adhesive application personnel, meets green and environmentally friendly production requirements, and has good peel strength and impact strength. It is suitable for applications in coatings, adhesives, automotive interiors and other fields, and has broad application prospects.

[0021] This invention provides a method for preparing acrylic pressure-sensitive adhesives for use in low-odor, low-VOC materials. The process is simple, easy to operate, and can be mass-produced. Detailed Implementation

[0022] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1 This embodiment provides an acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials and its preparation method: An acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials, comprising the following raw materials by weight: 60 parts of 2-ethylhexyl acrylate, 8 parts of 2-phenoxyethyl methacrylate, 3 parts of acrylic acid, 18 parts of hydrogenated terpene resin, 120 parts of ethyl acetate, 5 parts of modified nano silica, 1 part of benzoyl peroxide, 2 parts of hexamethylene diisocyanate, and 0.1 parts of antioxidant 1010.

[0024] The modified nano-silica is prepared through the following steps: 2.2 g of nano-silica was added to 80 mL of ethanol-water solution (the volume ratio of anhydrous ethanol to deionized water was 3:1), and ultrasonically dispersed for 0.5 h. Then, 1.6 mL of silane coupling agent KH-570 was added, and ultrasonication was continued for 10 min. The pH value was adjusted to 3 with glacial acetic acid, and then the temperature was raised to 70 °C and stirred for 8 h. After the reaction was completed, the mixture was cooled to room temperature and centrifuged. The supernatant was washed with anhydrous ethanol and deionized water until it was neutral. The product was then dried in a vacuum drying oven at 50 °C for 2 h to obtain modified nano-silica.

[0025] A method for preparing an acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials includes the following steps: Weigh out the components by weight, and under a nitrogen atmosphere, add the soft monomer, hard monomer, functional monomer, and modified nano-silica into a reactor. Heat the reactor to 68°C, add 3 / 20 parts by weight of the initiator and 3 / 5 parts by weight of the solvent, and stir for 2 hours. Then, add 17 / 20 parts by weight of the initiator and 2 / 5 parts by weight of the solvent dropwise into the reactor over 3.5 hours. After the addition is complete, react for 1.5 hours, then heat to 90°C and continue reacting for 1 hour. Cool to room temperature and discharge to obtain acrylic resin. Then, mix the acrylic resin, tackifying resin, crosslinking agent, and antioxidant obtained above and stir until homogeneous to obtain acrylic pressure-sensitive adhesive.

[0026] Example 2 The only difference from Example 1 is the preparation of the modified nano-silica: The modified nano-silica is prepared through the following steps: 2.4 g of nano-silica was added to 80 mL of ethanol-water solution (the volume ratio of anhydrous ethanol to deionized water was 3:1), and ultrasonically dispersed for 0.5 h. Then, 1.7 mL of silane coupling agent KH-570 was added, and ultrasonication was continued for 10 min. The pH value was adjusted to 3 with glacial acetic acid, and then the temperature was raised to 65 °C and stirred for 6-8 h. After the reaction was completed, the mixture was cooled to room temperature and centrifuged. The supernatant was washed with anhydrous ethanol and deionized water until it was neutral. The product was then dried in a vacuum drying oven at 50 °C for 2 h to obtain modified nano-silica.

[0027] Example 3 The only difference from Example 1 is the preparation of the modified nano-silica: The modified nano-silica is prepared through the following steps: 2.5 g of nano-silica was added to 80 mL of ethanol-water solution (the volume ratio of anhydrous ethanol to deionized water was 3:1), and ultrasonically dispersed for 0.5 h. Then, 1.8 mL of silane coupling agent KH-570 was added, and ultrasonication was continued for 15 min. The pH value was adjusted to 4 with glacial acetic acid, and then the temperature was raised to 70 °C and stirred for 7 h. After the reaction was completed, the mixture was cooled to room temperature and centrifuged. The supernatant was washed with anhydrous ethanol and deionized water until it was neutral. The product was then dried in a vacuum drying oven at 50 °C for 2 h to obtain modified nano-silica.

[0028] Example 4 The only difference from Example 1 is the amount of each component in the raw materials used: An acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials, comprising the following raw materials by weight: 68 parts of 2-ethylhexyl acrylate, 10 parts of 2-phenoxyethyl methacrylate, 4 parts of acrylic acid, 26 parts of hydrogenated terpene resin, 150 parts of ethyl acetate, 6 parts of modified nano silica, 2 parts of benzoyl peroxide, 3 parts of hexamethylene diisocyanate, and 0.15 parts of antioxidant 1010.

[0029] Example 5 The only difference from Example 1 is the amount of each component in the raw materials used: An acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials, comprising the following raw materials by weight: 75 parts of 2-ethylhexyl acrylate, 13 parts of 2-phenoxyethyl methacrylate, 6 parts of acrylic acid, 32 parts of hydrogenated terpene resin, 170 parts of ethyl acetate, 8 parts of modified nano silica, 13 parts of benzoyl peroxide, 3.5 parts of hexamethylene diisocyanate, and 0.8 parts of antioxidant 1010.

[0030] Comparative Example Comparative Example 1 The only difference from Example 1 is that the hard monomer 2-phenoxyethyl methacrylate is replaced with methyl methacrylate, the initiator benzoyl peroxide is replaced with dicumyl peroxide, and no modified nano-silica is added. An acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials, comprising the following raw materials by weight: 60 parts of 2-ethylhexyl acrylate, 8 parts of methyl methacrylate, 3 parts of acrylic acid, 18 parts of hydrogenated terpene resin, 120 parts of ethyl acetate, 1 part of dicumyl peroxide, 2 parts of hexamethylene diisocyanate, and 0.1 parts of antioxidant 1010.

[0031] Comparative Example 2 The only difference from Example 1 is that the hard monomer 2-phenoxyethyl methacrylate is replaced with methyl methacrylate, and the modified nano silica is replaced with nano silica. An acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials, comprising the following raw materials by weight: 60 parts of 2-ethylhexyl acrylate, 8 parts of methyl methacrylate, 3 parts of acrylic acid, 18 parts of hydrogenated terpene resin, 120 parts of ethyl acetate, 5 parts of nano silica, 1 part of benzoyl peroxide, 2 parts of hexamethylene diisocyanate, and 0.1 parts of antioxidant 1010.

[0032] Comparative Example 3 The only difference from Example 1 is that the modified nano-silica is replaced with nano-silica: An acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials, comprising the following raw materials by weight: 60 parts of 2-ethylhexyl acrylate, 8 parts of 2-phenoxyethyl methacrylate, 3 parts of acrylic acid, 18 parts of hydrogenated terpene resin, 120 parts of ethyl acetate, 5 parts of nano silica, 1 part of benzoyl peroxide, 2 parts of hexamethylene diisocyanate, and 0.1 parts of antioxidant 1010.

[0033] Comparative Example 4 The only difference from Example 1 is that no hard monomers are added to the raw materials: An acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials, comprising the following raw materials by weight: 60 parts of 2-ethylhexyl acrylate, 3 parts of acrylic acid, 18 parts of hydrogenated terpene resin, 120 parts of ethyl acetate, 5 parts of modified nano silica, 1 part of benzoyl peroxide, 2 parts of hexamethylene diisocyanate, and 0.1 parts of antioxidant 1010.

[0034] Comparative Example 5 The only difference from Example 1 is that no functional monomers are added to the raw materials: An acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials, comprising the following raw materials by weight: 60 parts of 2-ethylhexyl acrylate, 8 parts of 2-phenoxyethyl methacrylate, 18 parts of hydrogenated terpene resin, 120 parts of ethyl acetate, 5 parts of modified nano silica, 1 part of benzoyl peroxide, 2 parts of hexamethylene diisocyanate, and 0.1 parts of antioxidant 1010.

[0035] Comparative Example 6 The only difference from Example 1 is the amount of each component in the raw materials used: An acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials, comprising the following raw materials by weight: 40 parts of 2-ethylhexyl acrylate, 18 parts of 2-phenoxyethyl methacrylate, 3 parts of acrylic acid, 18 parts of hydrogenated terpene resin, 120 parts of ethyl acetate, 5 parts of modified nano silica, 1 part of benzoyl peroxide, 2 parts of hexamethylene diisocyanate, and 0.1 parts of antioxidant 1010.

[0036] Comparative Example 7 The only difference from Example 1 is the amount of each component in the raw materials used: An acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials, comprising the following raw materials by weight: 60 parts of 2-ethylhexyl acrylate, 5 parts of 2-phenoxyethyl methacrylate, 1 part of acrylic acid, 18 parts of hydrogenated terpene resin, 90 parts of ethyl acetate, 5 parts of modified nano silica, 1 part of benzoyl peroxide, 2 parts of hexamethylene diisocyanate, and 0.1 parts of antioxidant 1010.

[0037] Comparative Example 8 The only difference from Example 1 is the preparation method of the acrylic pressure-sensitive adhesive: A method for preparing an acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials includes the following steps: Weigh out the components by weight, and under a nitrogen atmosphere, heat the soft monomer, hard monomer, functional monomer, and modified nano-silica to 68°C. Add the initiator and solvent that have been mixed evenly, stir and react for 2 hours, then heat to 90°C and continue reacting for 1 hour. Cool to room temperature and discharge to obtain acrylic resin. Then mix the acrylic resin, tackifying resin, crosslinking agent and antioxidant obtained above, and stir until uniform to obtain acrylic pressure-sensitive adhesive.

[0038] Performance testing The acrylic pressure-sensitive adhesives prepared in Examples 1-5 and Comparative Examples 1-8 were subjected to the following performance tests: The acrylic pressure-sensitive adhesives prepared in the examples and comparative examples were coated onto a 25 μm PET substrate, dried at 100°C for 5 min, and cured to form a film to prepare pressure-sensitive adhesive tape. The film thickness was 60 μm.

[0039] (1) 180° peel force: The peel force of the pressure-sensitive tape is tested according to GB / T 2792-1998 standard.

[0040] (2) Holding power: The holding power of pressure-sensitive tape is tested according to GB / T 4851-1998 standard.

[0041] (3) High temperature peel resistance: According to GB / T 7122-1996 standard, the high temperature peel resistance effect is tested. The tape is applied to a stainless steel plate and placed in an environment of 260℃ for 4 hours. After cooling, the tape is peeled off and the residue on the tape is observed.

[0042] The test results are shown in Table 1: Table 1 As can be seen from Table 1, the pressure-sensitive tapes made from the acrylic pressure-sensitive adhesives prepared in Examples 1-5 have excellent 180° peel strength and durability, and there is no residue after peeling.

[0043] Combining Comparative Examples 1-3 with Example 1, it can be seen that Comparative Example 1 did not contain modified nano-silica, while Comparative Examples 2-3 contained modified nano-silica. Furthermore, referring to the data in Table 1, it can be seen that the pressure-sensitive tape prepared in Comparative Example 1 exhibited poor 180° peel strength and durability, while the peel strength and durability of the tapes prepared in Comparative Examples 2-3 were higher than those in Comparative Example 1. Therefore, the addition of nano-silica can significantly improve the rheology and adhesion of polyacrylate emulsions. Its interfacial forces between components can toughen and strengthen the pressure-sensitive adhesive film, while effectively improving the 180° peel strength and durability.

[0044] Comparing Comparative Examples 4-8 with Example 1, it can be seen that no hard monomer was added in Comparative Example 4, no functional monomer was added in Comparative Example 5, the amounts used in Comparative Examples 6-7 exceeded the optimal range of the formulation in this invention, and the initiator and solvent were not added stepwise in the preparation scheme of Comparative Example 8. Furthermore, considering the data in Table 1, it can be seen that the peel strength and durability of Comparative Examples 4-8 are relatively poor, significantly lower than those of Example 1. Therefore, it is evident that the type and amount of raw materials, as well as the preparation steps, all affect the adhesive performance and heat resistance of acrylic pressure-sensitive adhesives.

[0045] (4) Odor test: Take a 25mm×25mm sample and put it into a sealed, clean wide-mouth bottle with a glass stopper. Then put it in an oven at 80℃ for 2 hours. Five professional odor testers will evaluate the odor. The average value of the evaluation values ​​of the five testers will be taken as the test odor level (the odor level is divided into 6 levels: level 1 is no odor, level 2 is slightly odorous, level 3 is odorous but not irritating, level 4 is irritating, level 5 is strongly irritating, and level 6 is unbearable).

[0046] (5) VOC and FOG: The thermal desorption method was used to determine the VDA 278-2011 standard.

[0047] The test results are shown in Table 2: Table 2 As can be seen from Table 2, the acrylic pressure-sensitive adhesives prepared in Examples 1-5 have a significant effect on odor control, effectively reducing the release of VOCs and FOGs, and can stably control the odor level at a low level of 2 with stable performance.

[0048] Therefore, the acrylic pressure-sensitive adhesive and its preparation method provided by the present invention, which can be used in low-odor and low-VOC materials, can significantly reduce the generation of irritating odors. The acrylic pressure-sensitive adhesive has obvious advantages in terms of odor and low volatile emissions, and meets the requirements of environmental protection and high quality applications.

[0049] As can be seen from Comparative Examples 1-2 and Example 1, the hard monomer and initiator used in Comparative Example 1 are methyl methacrylate monomer with a high odor and dicumyl peroxide, respectively. Therefore, the pressure-sensitive tape prepared has a distinct odor and has high VOC and FOG release.

[0050] As can be seen from Comparative Examples 3-8 and Example 1, the amount and type of raw materials used in acrylic pressure-sensitive adhesives, as well as the preparation method, can affect the odor and low-volatile emissions of acrylic pressure-sensitive adhesives.

[0051] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0052] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials, characterized in that, By weight, it includes the following ingredients: 60-75 parts soft monomer, 8-13 parts hard monomer, 3-6 parts functional monomer, 18-32 parts tackifying resin, 110-180 parts solvent, 5-8 parts modified nano silica, 1-3 parts initiator, 2-4 parts crosslinking agent, and 0.1-1 parts antioxidant.

2. The acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials according to claim 1, characterized in that, The modified nano-silica is prepared through the following steps: Nano-silica was added to an ethanol aqueous solution and ultrasonically dispersed for 0.5 h. Then, silane coupling agent KH-570 was added, and ultrasonication was continued for 10-15 min. The pH value was adjusted to 3-4 with glacial acetic acid. The temperature was then raised to 65-70℃ and stirred for 6-8 h. After the reaction was completed, the mixture was cooled to room temperature and centrifuged. After washing until neutral, the mixture was vacuum dried for 2 h to obtain modified nano-silica.

3. The acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials according to claim 2, characterized in that, The ratio of nano-silica, aqueous ethanol solution and silane coupling agent KH-570 is 2.2-2.5g: 80mL: 1.6-1.8mL.

4. The acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials according to claim 1, characterized in that, The soft monomer is at least one of 2-ethylhexyl acrylate and n-butyl acrylate.

5. The acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials according to claim 1, characterized in that, The hard monomer is at least one of 2-phenoxyethyl methacrylate and tetrahydrofuran methacrylate.

6. The acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials according to claim 1, characterized in that, The functional monomer is at least one of acrylic acid and hydroxyethyl acrylate.

7. The acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials according to claim 1, characterized in that, The solvent is ethyl acetate; the initiator is one of benzoyl peroxide and azobisisobutyronitrile.

8. The acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials according to claim 1, characterized in that, The tackifying resin is one of hydrogenated terpene resin, hydrogenated C5 petroleum resin, and hydrogenated rosin glycerol ester.

9. An acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials according to claim 1, characterized in that, The crosslinking agent is one of hexamethylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 4,4-dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate trimer; the antioxidant is a hindered phenolic antioxidant; the hindered phenolic antioxidant is one of antioxidant 1010 and antioxidant 1076.

10. A method for preparing an acrylic pressure-sensitive adhesive for use in low-odor, low-VOC materials according to claim 1, characterized in that, Includes the following steps: Weigh out the components by weight, and under a nitrogen atmosphere, add the soft monomer, hard monomer, functional monomer, modified nano-silica, 3 / 20 parts by weight of initiator, and 3 / 5 parts by weight of solvent into a reactor. Heat to 68-75℃ and stir for 2-3 hours. Mix 17 / 20 parts by weight of initiator and 2 / 5 parts by weight of solvent evenly and add dropwise to the reactor over 3.5-4.0 hours. After the addition is complete, react for 1.5-2.5 hours, then heat to 90-95℃ and continue reacting for 1-2 hours. Cool to room temperature and discharge to obtain acrylic resin. Then mix the obtained acrylic resin, tackifying resin, crosslinking agent, and antioxidant, and stir until homogeneous to obtain acrylic pressure-sensitive adhesive.

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