Raw material for preparing pressure-sensitive adhesive, pressure-sensitive adhesive and preparation method of pressure-sensitive adhesive

Abstract

The invention discloses a raw material for preparing a pressure-sensitive adhesive, the pressure-sensitive adhesive and a preparation method of the pressure-sensitive adhesive, relates to the technical field of high polymer materials, and aims to solve the problem of poor compactness due to low density of the pressure-sensitive adhesive. Wherein the raw materials for preparing the pressure-sensitive adhesive comprise the following materials in parts by weight: 25 to 35 parts of polyether polyol, 26.5 to 36.5 parts of isocyanate, 17 to 23 parts of hydroxypropyl methacrylate, 7 to 13 parts of acid functional group acrylate, 2 to 2.6 parts of nano silicon dioxide, 4 to 6 parts of trimethylolpropane triacrylate, 1.5 to 2.5 parts of a photoinitiator and 0.8 to 1.2 parts of a silane coupling agent.

Description

Technical Field

[0001] The present application relates to the technical field of polymer materials, and in particular to a raw material for preparing a pressure-sensitive adhesive, a pressure-sensitive adhesive and a preparation method thereof. Background Art

[0002] As a new type of radiation curing material, pressure sensitive adhesive has developed rapidly in recent years. At present, pressure sensitive adhesive has good high temperature resistance, but there are still large gaps between molecules and low density, which makes the density poor, resulting in poor resistance to chemical media permeability, low shear strength and peel strength. When used in high humidity and high corrosion environments, it is easy to detach from the bonded surface and lose the bonding effect. Summary of the invention

[0003] The purpose of the present application is to provide a raw material for preparing a pressure-sensitive adhesive, a pressure-sensitive adhesive and a preparation method thereof, in order to solve the problem that the pressure-sensitive adhesive has a low density and poor compactness.

[0004] In order to achieve the above objectives, this application adopts the following technical solutions:

[0005] In the first aspect, the present application provides a raw material for preparing a pressure-sensitive adhesive. The raw material for preparing a pressure-sensitive adhesive includes the following materials in parts by weight: 25 to 35 parts of polyether polyol, 26.5 to 36.5 parts of isocyanate, 17 to 23 parts of hydroxypropyl methacrylate, 7 to 13 parts of acid functional acrylate, 2 to 2.6 parts of nano-silica, 4 to 6 parts of trimethylolpropane triacrylate, 1.5 to 2.5 parts of photoinitiator, and 0.8 to 1.2 parts of silane coupling agent.

[0006] Among the raw materials for preparing the pressure-sensitive adhesive provided in the embodiments of the present application, 25 to 35 parts of polyether polyol are the main matrix of the pressure-sensitive adhesive, which provides flexibility and ductility, helps the pressure-sensitive adhesive to better adapt to the deformation of different surfaces during application and improves adhesion.

[0007] 26.5 to 36.5 parts of isocyanate are used to react with polyether polyol to form polyurethane chains and strong chemical bonds, thereby enhancing the cohesion and adhesion of the pressure-sensitive adhesive. This cross-linking reaction not only improves the initial adhesion of the pressure-sensitive adhesive, but also gives the pressure-sensitive adhesive better temperature resistance and weather resistance.

[0008] 17 to 23 parts of hydroxypropyl methacrylate are used to enhance the performance of the adhesive, improve fluidity and sizing properties. At the same time, hydroxypropyl methacrylate can also react with isocyanate and polyether polyol to increase the degree of crosslinking; and can also undergo polymerization under the action of a photoinitiator to form a long-chain polymer, enhance the pressure-sensitive adhesive effect and improve adhesion, thereby improving the interface adhesion between the pressure-sensitive adhesive and the substrate.

[0009] The acid functional groups in 7 to 13 parts of the acid functional acrylate can react with the hydroxyl groups in the polyether polyol, and under the action of the photoinitiator, the double bonds in the acid functional acrylate undergo polymerization reaction under the influence of free radicals to form long-chain polymers, thereby enhancing the pressure-sensitive adhesive effect and improving the adhesion, thereby improving the interface adhesion between the pressure-sensitive adhesive and the substrate.

[0010] 4 to 6 parts of trimethylolpropane triacrylate is a trifunctional acrylate that provides multiple double bond sites and can be cross-linked with acid functional acrylate through the above-mentioned polymerization reaction, further promoting the cross-linking reaction and increasing the overall strength and temperature resistance of the pressure-sensitive adhesive.

[0011] After 1.5 to 2.5 parts of the photoinitiator are irradiated with ultraviolet light, they absorb the energy of light, split into active free radicals, and initiate the polymerization reaction of the acid functional acrylate, that is, the free radicals generated by the photoinitiator can react with the double bonds of the acid functional acrylate to start the polymerization process and form a polymer chain; and the formed polymer chain is cross-linked with the double bonds in trimethylolacrylate, which promotes the cross-linking and curing of the pressure-sensitive adhesive. At the same time, the hydroxyl groups in the polyurethane chain generated by polyether polyol, isocyanate and hydroxypropyl methacrylate react with the acid functional groups of the acid functional acrylate to improve the cross-linking degree of the pressure-sensitive adhesive, so that the above reaction system forms a three-dimensional network structure with a high degree of cross-linking, which improves the strength and adhesion of the pressure-sensitive adhesive, and then cross-links and cures the pressure-sensitive adhesive.

[0012] 2 to 2.6 parts of nano-silica can fill the intermolecular gaps of the spatial network structure of the pressure-sensitive adhesive, increase the density of the pressure-sensitive adhesive, and then increase the shear strength and peel strength of the pressure-sensitive adhesive, and also effectively slow down the penetration of water and chemical media.

[0013] 0.8 to 1.2 parts of silane coupling agent are used to improve the affinity between the above components, promote the formation of good compatibility between the components, and further improve the crosslinking degree of the pressure-sensitive adhesive.

[0014] Therefore, through the combined action of the above-mentioned 25 to 35 parts of polyether polyol, 26.5 to 36.5 parts of isocyanate, 17 to 23 parts of hydroxypropyl methacrylate, 7 to 13 parts of acid functional acrylate, 2 to 2.6 parts of nano-silica, 4 to 6 parts of trimethylolpropane triacrylate, 1.5 to 2.5 parts of photoinitiator and 0.8 to 1.2 parts of silane coupling agent, the molecular gap of the pressure-sensitive adhesive is small, the density is significantly increased, and the compactness is improved, which not only improves the shear strength and peel strength of the pressure-sensitive adhesive, but also effectively slows down the penetration of water and chemical media.

[0015] In some embodiments, the following materials are included in parts by weight: 30 parts of polyether polyol, 31.5 parts of isocyanate, 20 parts of hydroxypropyl methacrylate, 10 parts of acid functional acrylate, 2.3 parts of nano-silica, 5 parts of trimethylolpropane triacrylate, 2 parts of photoinitiator and 1 part of silane coupling agent.

[0016] In some embodiments, the photoinitiator includes at least one of 184 thermal decomposition type photoinitiator, 1173 photoinitiator, triphenyl oxide and 2,2-dimethoxyphenyl acrylate.

[0017] In some embodiments, the silane coupling agent includes at least one of KH-570 silane coupling agent, KH-560 silane coupling agent, KH-550 silane coupling agent, KH-651 silane coupling agent, γ-aminopropyltriethoxysilane, and 3-aminopropyltriethoxysilane.

[0018] In some embodiments, the raw materials for preparing the pressure-sensitive adhesive further include: 0.6 to 0.8 parts by weight of rosin hydrophobic malic acid glyceride tackifying resin.

[0019] In some embodiments, the rosin hydrophobic glyceryl malate tackifying resin is 0.7 parts.

[0020] In some embodiments, the average particle size of nano-silica is in the range of 0.2 nm to 0.3 nm.

[0021] In a second aspect, the present application provides a method for preparing a pressure-sensitive adhesive. The method for preparing the pressure-sensitive adhesive comprises:

[0022] Under protective gas, polyether polyol and isocyanate are reacted to form a first polyurethane prepolymer.

[0023] Hydroxypropyl methacrylate is added into the first polyurethane prepolymer to react and generate the second polyurethane prepolymer.

[0024] Acid functional acrylate, nano silicon dioxide, trimethylolpropane triacrylate, photoinitiator and silane coupling agent are added to the second polyurethane prepolymer to react and generate polyurethane acrylate initial liquid.

[0025] The polyurethane acrylate initial solution is applied to form a wet film.

[0026] The wet film is cured under ultraviolet light to obtain a pressure-sensitive adhesive.

[0027] It can be understood that the beneficial effects that can be achieved by the method for preparing the pressure-sensitive adhesive provided in the above embodiments of the present application can refer to the beneficial effects of the raw materials used for preparing the pressure-sensitive adhesive mentioned above, and will not be repeated here.

[0028] In some embodiments, polyether polyol and isocyanate are reacted under protective gas to generate a polyurethane prepolymer, and the reaction temperature ranges from 75° C. to 85° C.

[0029] In some embodiments, acid functional acrylate, nano-silica, trimethylolpropane triacrylate, photoinitiator and silane coupling agent are added to the second polyurethane prepolymer, and further comprising:

[0030] Add rosin hydrophobic malic acid glyceryl ester tackifying resin.

[0031] In a third aspect, the present application provides a pressure-sensitive adhesive prepared by the method for preparing a pressure-sensitive adhesive as described in any one of the above embodiments.

[0032] It can be understood that the beneficial effects that can be achieved by the pressure-sensitive adhesive provided in the above embodiments of the present application can refer to the beneficial effects of the raw materials used to prepare the pressure-sensitive adhesive mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 A flow chart of a method for preparing a pressure-sensitive adhesive is provided for an embodiment of the present application;

[0035] Figure 2 A schematic diagram of a method for preparing a pressure-sensitive adhesive is provided for an embodiment of the present application. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0037] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0038] In the present application, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, article or device including the element.

[0039] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0040] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0041] Pressure-sensitive adhesive is a type of adhesive that is sensitive to pressure and is widely used in packaging, medical and health care, printing, construction, manufacturing and other fields. Traditional pressure-sensitive adhesives include solvent-based, emulsion-based, and hot-melt-based. The preparation process of solvent-based pressure-sensitive adhesives involves the problem of solvent volatilization pollution, and is close to being eliminated; emulsion-based pressure-sensitive adhesives are non-toxic and pollution-free, but usually have poor water resistance and a long drying time; and hot-melt pressure-sensitive adhesives are greatly affected by temperature, are difficult to apply at room temperature, have poor cohesion at high temperatures, and cannot be used in high-temperature environments.

[0042] As a new type of radiation curing material, light-curing pressure-sensitive adhesive has developed rapidly in recent years. It can form a cross-linked network structure under the action of light curing, and the entire preparation process is economical, environmentally friendly and efficient. Currently available light-curing pressure-sensitive adhesives usually have good high temperature resistance, but still have problems such as large intermolecular gaps, poor resistance to chemical media permeability, low shear strength and peel strength. When used in high humidity and high corrosion environments, it is easy to detach from the bonded surface and lose the bonding effect.

[0043] Based on this, an embodiment of the present application provides a raw material for preparing a pressure-sensitive adhesive. The raw material for preparing a pressure-sensitive adhesive includes the following materials in parts by weight: 25 to 35 parts of polyether polyol, 26.5 to 36.5 parts of isocyanate, 17 to 23 parts of hydroxypropyl methacrylate, 7 to 13 parts of acid functional acrylate, 2 to 2.6 parts of nano-silica, 4 to 6 parts of trimethylolpropane triacrylate, 1.5 to 2.5 parts of photoinitiator, and 0.8 to 1.2 parts of silane coupling agent.

[0044] For example, the polyether polyol may be 25 parts, 27 parts, 29 parts, 31 parts, 33 parts or 35 parts, etc., which is not limited here.

[0045] For example, the amount of isocyanate may be 26.5 parts, 28.5 parts, 30.5 parts, 32.5 parts, 34.5 parts or 36.5 parts, etc., which is not limited herein.

[0046] For example, the amount of hydroxypropyl methacrylate may be 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts or 23 parts, etc., and is not limited thereto.

[0047] For example, the acid functional acrylate may be 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts or 13 parts, etc., which is not limited here.

[0048] For example, the amount of nano-silicon dioxide can be 2 parts, 2.1 parts, 2.2 parts, 2.3 parts, 2.4 parts, 2.5 parts or 2.6 parts, etc., which is not limited here.

[0049] For example, the amount of trimethylolpropane triacrylate may be 4 parts, 4.5 parts, 5 parts, 5.5 parts or 6 parts, etc., which is not limited here.

[0050] For example, the photoinitiator may be 1.5 parts, 1.7 parts, 1.9 parts, 2.1 parts, 2.3 parts or 2.5 parts, etc., which is not limited here.

[0051] For example, the silane coupling agent may be 0.8 parts, 0.9 parts, 1.0 parts, 1.1 parts or 1.2 parts, etc., which is not limited here.

[0052] Among them, 25 to 35 parts of polyether polyol is the main matrix of the pressure-sensitive adhesive, which provides flexibility and ductility, helps the pressure-sensitive adhesive to better adapt to the deformation of different surfaces during application and improves adhesion.

[0053] 26.5 to 36.5 parts of isocyanate are used to react with polyether polyol to form polyurethane chains and strong chemical bonds, thereby enhancing the cohesion and adhesion of the pressure-sensitive adhesive. This cross-linking reaction not only improves the initial adhesion of the pressure-sensitive adhesive, but also gives the pressure-sensitive adhesive better temperature resistance and weather resistance.

[0054] 17 to 23 parts of hydroxypropyl methacrylate are used to enhance the performance of the adhesive, improve fluidity and sizing properties. At the same time, hydroxypropyl methacrylate can also react with isocyanate and polyether polyol to increase the degree of crosslinking; and can also undergo polymerization under the action of a photoinitiator to form a long-chain polymer, enhance the pressure-sensitive adhesive effect and improve adhesion, thereby improving the interface adhesion between the pressure-sensitive adhesive and the substrate.

[0055] The acid functional groups in 7 to 13 parts of the acid functional acrylate can react with the hydroxyl groups in the polyether polyol, and under the action of the photoinitiator, the double bonds in the acid functional acrylate undergo polymerization reaction under the influence of free radicals to form long-chain polymers, thereby enhancing the pressure-sensitive adhesive effect and improving the adhesion, thereby improving the interface adhesion between the pressure-sensitive adhesive and the substrate.

[0056] 4 to 6 parts of trimethylolpropane triacrylate is a trifunctional acrylate that provides multiple double bond sites and can be cross-linked with acid functional acrylate through the above-mentioned polymerization reaction, further promoting the cross-linking reaction and increasing the overall strength and temperature resistance of the pressure-sensitive adhesive.

[0057] After 1.5 to 2.5 parts of the photoinitiator are irradiated with ultraviolet light, they absorb the energy of light, split into active free radicals, and initiate the polymerization reaction of the acid functional acrylate, that is, the free radicals generated by the photoinitiator can react with the double bonds of the acid functional acrylate to start the polymerization process and form polymer chains; and the formed polymer chains are cross-linked with the double bonds in trimethylolacrylate, which promotes the cross-linking and curing of the pressure-sensitive adhesive. At the same time, the hydroxyl groups in the polyurethane chains generated by polyether polyol, isocyanate and hydroxypropyl methacrylate react with the acid functional groups of the acid functional acrylate to improve the cross-linking degree of the pressure-sensitive adhesive, so that the above reaction system forms a three-dimensional network structure with a high degree of cross-linking, which improves the strength and adhesion of the pressure-sensitive adhesive, and then cross-links and cures the pressure-sensitive adhesive.

[0058] 2 to 2.6 parts of nano-silica can fill the intermolecular gaps of the spatial network structure of the pressure-sensitive adhesive, increase the density of the pressure-sensitive adhesive, and then increase the shear strength and peel strength of the pressure-sensitive adhesive, and also effectively slow down the penetration of water and chemical media.

[0059] 0.8 to 1.2 parts of silane coupling agent are used to improve the affinity between the above components, promote the formation of good compatibility between the components, and further improve the crosslinking degree of the pressure-sensitive adhesive.

[0060] Therefore, through the combined action of the above-mentioned 25 to 35 parts of polyether polyol, 26.5 to 36.5 parts of isocyanate, 17 to 23 parts of hydroxypropyl methacrylate, 7 to 13 parts of acid functional acrylate, 2 to 2.6 parts of nano-silica, 4 to 6 parts of trimethylolpropane triacrylate, 1.5 to 2.5 parts of photoinitiator and 0.8 to 1.2 parts of silane coupling agent, the molecular gap of the pressure-sensitive adhesive is small, the density is significantly increased, and the compactness is improved, which not only improves the shear strength and peel strength of the pressure-sensitive adhesive, but also effectively slows down the penetration of water and chemical media.

[0061] In some embodiments, the following materials are included in parts by weight: 30 parts of polyether polyol, 31.5 parts of isocyanate, 20 parts of hydroxypropyl methacrylate, 10 parts of acid functional acrylate, 2.3 parts of nano-silica, 5 parts of trimethylolpropane triacrylate, 2 parts of photoinitiator and 1 part of silane coupling agent.

[0062] It can be understood that, through the above-mentioned configuration, the intermolecular gaps of the pressure-sensitive adhesive can be further reduced, the density can be significantly increased, and the compactness can be improved, which not only improves the shear strength and peel strength of the pressure-sensitive adhesive, but also effectively slows down the penetration of water and chemical media.

[0063] In some embodiments, the photoinitiator includes at least one of 184 thermal decomposition type photoinitiator, 1173 photoinitiator, triphenyl oxide and 2,2-dimethoxyphenyl acrylate.

[0064] It can be understood that at least one of the above-mentioned 184 thermal decomposition photoinitiator, 1173 photoinitiator, triphenyl oxide and 2,2-dimethoxyphenyl acrylate as a photoinitiator can quickly form free radicals under ultraviolet light irradiation, strengthen the cross-linking reaction, increase the cross-linking density of the pressure-sensitive adhesive, and improve the mechanical properties and durability of the pressure-sensitive adhesive.

[0065] In some embodiments, the silane coupling agent includes at least one of KH-570 silane coupling agent, KH-560 silane coupling agent, KH-550 silane coupling agent, KH-651 silane coupling agent, γ-aminopropyltriethoxysilane, and 3-aminopropyltriethoxysilane.

[0066] It can be understood that at least one of the above-mentioned KH-570 silane coupling agent, KH-560 silane coupling agent, KH-550 silane coupling agent, KH-651 silane coupling agent, γ-aminopropyltriethoxysilane and 3-aminopropyltriethoxysilane as a silane coupling agent can improve the affinity between the components of the pressure-sensitive adhesive raw material, promote the formation of good compatibility between the components, and improve the crosslinking degree of the pressure-sensitive adhesive.

[0067] In some embodiments, the raw materials for preparing the pressure-sensitive adhesive further include: 0.6 to 0.8 parts by weight of rosin hydrophobic malic acid glyceride tackifying resin.

[0068] For example, the amount of the rosin hydrophobic glyceryl malate tackifying resin may be 0.6 parts, 0.7 parts, or 0.8 parts, etc., and is not limited thereto.

[0069] It can be understood that the active groups in 0.6 to 0.8 parts by weight of the rosin hydrophobic malic acid glyceride tackifying resin can react with the components in the pressure-sensitive adhesive raw material to accelerate the reaction speed and increase the cross-linking degree of the pressure-sensitive adhesive.

[0070] In some embodiments, the rosin hydrophobic glyceryl malate tackifying resin is 0.7 parts.

[0071] In some embodiments, the average particle size of nano-silica is in the range of 0.2 nm to 0.3 nm.

[0072] For example, the average particle size of nano-silicon dioxide can be 0.2 nm, 0.25 nm or 0.3 nm, etc., which is not limited here.

[0073] It can be understood that the above-mentioned nano-silica has a small average particle size, which can better fill the intermolecular gaps of the spatial network structure of the pressure-sensitive adhesive, increase the density of the pressure-sensitive adhesive, and then increase the shear strength and peel strength of the pressure-sensitive adhesive, and also effectively slow down the penetration of water and chemical media.

[0074] The embodiments of the present application provide a method for preparing a pressure-sensitive adhesive. Figure 1 As shown, the preparation method of the pressure-sensitive adhesive includes: S1 to S5.

[0075] S1: Under protective gas, polyether polyol and isocyanate are reacted to form a first polyurethane prepolymer.

[0076] Exemplarily, the reaction temperature ranges from 75°C to 85°C.

[0077] For example, the reaction temperature can be 75° C., 78° C., 80° C., 83° C. or 85° C., etc., but is not limited thereto.

[0078] S2: adding hydroxypropyl methacrylate to the first polyurethane prepolymer to react and generate a second polyurethane prepolymer.

[0079] S3: adding acid functional acrylate, nano silicon dioxide, trimethylolpropane triacrylate, photoinitiator and silane coupling agent to the second polyurethane prepolymer to react and generate polyurethane acrylate initial liquid.

[0080] S4: Applying the polyurethane acrylate initial liquid to form a wet film.

[0081] S5: Curing the wet film under ultraviolet light to obtain a pressure-sensitive adhesive.

[0082] In some embodiments, S3 adds acid functional acrylate, nano-silica, trimethylolpropane triacrylate, a photoinitiator and a silane coupling agent to the second polyurethane prepolymer, and further includes: S3.1.

[0083] S3.1: Add rosin hydrophobic malic acid glyceride tackifying resin.

[0084] For example, Figure 2As shown, the polyether polyol is subjected to reduced pressure distillation, and then the temperature of the distilled polyether polyol is raised to 75°C to 85°C, and then isocyanate is added dropwise, and the reaction is stopped after 3.0 hours to 3.5 hours; then hydroxypropyl methacrylate is added, and the reaction is continued for 1.0 hour to 1.5 hours, and then cooled to room temperature. Then acid functional acrylate, nano silica, trimethylolpropane triacrylate, 184 thermal decomposition type photoinitiator, KH-570 silane coupling agent and rosin hydrophobic malic acid glyceride tackifying resin are added and stirred until the thermal decomposition type photoinitiator is dissolved. Then a paint film applicator is used for coating to obtain a wet film with a thickness of 1.0 mm to 2.0 mm; finally, the wet film is placed 10 cm to 40 cm below the lamp tube of the ultraviolet curing machine, and taken out after irradiation for 30 seconds to 150 seconds to obtain a light-cured pressure-sensitive adhesive.

[0085] The above raw materials for preparing pressure-sensitive adhesive and the pressure-sensitive adhesive prepared by the preparation method of pressure-sensitive adhesive in any of the above embodiments have small intermolecular gaps, good resistance to chemical medium permeability, high shear strength and peel strength, and are suitable for high humidity and high corrosion environments.

[0086] The pressure-sensitive adhesive is further described in detail below by taking specific embodiments as examples.

[0087] Example 1

[0088] Embodiment 1 provides a pressure-sensitive adhesive. The raw materials used to prepare the pressure-sensitive adhesive include:

[0089] The preparation method comprises: 30 parts of polyether polyol, 31.5 parts of isocyanate, 20 parts of hydroxypropyl methacrylate, 10 parts of acid functional acrylate, 2.3 parts of nano silicon dioxide, 5 parts of trimethylolpropane triacrylate, 2 parts of 184 thermal decomposition type photoinitiator, 1 part of KH-570 silane coupling agent and 0.7 parts of rosin hydrophobic malic acid glyceride tackifying resin.

[0090] The preparation method of the pressure-sensitive adhesive comprises:

[0091] T1: The polyether polyol was subjected to reduced pressure distillation, and then the distilled polyol was added into a four-necked flask with nitrogen, a thermometer, a condenser and a stirring paddle, and the temperature was raised to 80°C.

[0092] T2: Isocyanate was added dropwise to a four-necked flask, and the reaction was stopped after 3.3 hours to generate the first polyurethane prepolymer.

[0093] T3: Add hydroxypropyl methacrylate to the first polyurethane prepolymer in the four-necked flask, continue the reaction for 1.25 hours to generate a second polyurethane prepolymer, and then cool to room temperature.

[0094] T4: Acid functional acrylate, nano-silica, trimethylolpropane triacrylate, 184 thermal decomposition type photoinitiator, KH-570 silane coupling agent and rosin hydrophobic malic acid glyceride tackifying resin are added to the four-necked flask containing the second polyurethane prepolymer respectively, and stirred until the 184 thermal decomposition type photoinitiator is dissolved.

[0095] T5: Coating was performed using a paint film applicator to obtain a wet film with a thickness of 1.5 mm.

[0096] T6: Place the wet film 25 cm below the lamp tube of the UV curing machine, irradiate for 90 seconds and then take it out to obtain a pressure-sensitive adhesive.

[0097] Performance Testing

[0098] In order to verify the performance of the pressure-sensitive adhesive of Example 1 of the present application, the following density, peel strength test, shear strength test, moisture and heat resistance test, and chemical medium immersion resistance test were performed:

[0099] The density test was conducted in accordance with GB / T 1033.1-2008 "Determination of density of non-foamed plastics Part 1: Immersion method, liquid pycnometer method and titration method". The cured adhesive film of the pressure-sensitive adhesive of Example 1 was cut into three samples with a mass of no more than 10 g, and the mass of each sample was weighed in the air and immersed in a beaker filled with immersion liquid on an analytical balance, and the density of the sample was calculated based on the density of the immersion liquid.

[0100] The peel strength test was conducted in accordance with GB / T 2792-2014 "Test method for peel strength of adhesive tape". The photosensitive adhesive of Example 1 was evenly coated on a polyethylene terephthalate (PET) film to form an adhesive tape, and three 300 mm long samples were cut. One end of the adhesive tape was pressed and attached to one end of the steel plate. After the state was adjusted, the test was started and the measured peel strength was recorded.

[0101] The shear strength test was conducted in accordance with GB / T 7124-2008 "Determination of tensile shear strength of adhesives (rigid material to rigid material)". The pressure-sensitive adhesive of Example 1 was evenly coated on a polyethylene terephthalate (PET) film to form an adhesive tape, and then a sample with a bonding surface length of 12.5 mm was prepared on a steel plate. After the state was adjusted, the test was started and the measured shear strength was recorded.

[0102] The moisture and heat resistance test was conducted in accordance with GB / T 1740-2007 "Determination of moisture and heat resistance of paint films". The pressure-sensitive adhesive of Example 1 was coated on a 150 mm × 70 mm steel plate, and the upper and lower sides of the steel plate were fully sealed to prepare three samples. After the state was adjusted for 24 hours, the steel plate was vertically hung in a constant temperature and humidity chamber, and a 1000-hour moisture and heat resistance test was conducted in the constant temperature and humidity chamber at a temperature of 47°C and a relative humidity of 96%.

[0103] The chemical medium immersion test was conducted in accordance with GB / T 9274-1988 "Determination of resistance of paints and varnishes to liquid media". The pressure-sensitive adhesive of Example 1 was coated on a 150 mm × 70 mm steel plate, and the upper and lower sides of the steel plate were fully sealed to prepare 10 samples (one of which was a control sample). After the state was adjusted for 24 hours, the steel plate was immersed in three solutions of 3% NaCl, 5% NaOH, and 5% H2SO4, with 3 pieces immersed in each solution, and the immersion height was 2 / 3.

[0104] Table 1 Performance test results of Example 1

[0105]

[0106] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A raw material for preparing a pressure-sensitive adhesive, characterized in that: The invention comprises the following materials in parts by weight: 25 to 35 parts of polyether polyol, 26.5 to 36.5 parts of isocyanate, 17 to 23 parts of hydroxypropyl methacrylate, 7 to 13 parts of acid functional acrylate, 2 to 2.6 parts of nano silicon dioxide, 4 to 6 parts of trimethylolpropane triacrylate, 1.5 to 2.5 parts of photoinitiator and 0.8 to 1.2 parts of silane coupling agent.

2. The raw material for preparing a pressure-sensitive adhesive according to claim 1, characterized in that: The invention comprises the following materials in parts by weight: 30 parts of polyether polyol, 31.5 parts of isocyanate, 20 parts of hydroxypropyl methacrylate, 10 parts of acid functional acrylate, 2.3 parts of nano silicon dioxide, 5 parts of trimethylolpropane triacrylate, 2 parts of photoinitiator and 1 part of silane coupling agent.

3. The raw material for preparing a pressure-sensitive adhesive according to claim 1, characterized in that: The photoinitiator comprises at least one of 184 thermal decomposition type photoinitiator, 1173 photoinitiator, triphenyl oxide and 2,2-dimethoxyphenyl acrylate.

4. The raw material for preparing a pressure-sensitive adhesive according to claim 1, characterized in that: The silane coupling agent includes at least one of KH-570 silane coupling agent, KH-560 silane coupling agent, KH-550 silane coupling agent, KH-651 silane coupling agent, γ-aminopropyltriethoxysilane and 3-aminopropyltriethoxysilane.

5. The raw material for preparing a pressure-sensitive adhesive according to claim 1, characterized in that: Also includes: The weight range of the rosin hydrophobic malic acid glyceryl tackifying resin is 0.6 to 0.8 parts.

6. The raw material for preparing a pressure-sensitive adhesive according to claim 5, characterized in that: The amount of the rosin hydrophobic glyceryl malate tackifying resin is 0.7 parts.

7. The raw material for preparing a pressure-sensitive adhesive according to claim 1, characterized in that: The average particle size of the nano silicon dioxide is in the range of 0.2nm to 0.3nm.

8. A method for preparing a pressure-sensitive adhesive, characterized in that: include: Under a protective gas, reacting polyether polyol and isocyanate to generate a first polyurethane prepolymer; Adding hydroxypropyl methacrylate to the first polyurethane prepolymer to react and generate a second polyurethane prepolymer; Adding acid functional acrylate, nano silicon dioxide, trimethylolpropane triacrylate, photoinitiator and silane coupling agent to the second polyurethane prepolymer to react and generate polyurethane acrylate initial liquid; Applying the polyurethane acrylate initial solution to form a wet film; The wet film is cured under ultraviolet light to obtain the pressure-sensitive adhesive.

9. The method for preparing a pressure-sensitive adhesive according to claim 8, characterized in that: The polyether polyol and isocyanate are reacted under protective gas to generate a polyurethane prepolymer, and the reaction temperature range is 75° C. to 85° C.

10. The method for preparing a pressure-sensitive adhesive according to claim 8, characterized in that: The method of adding acid functional acrylate, nano silicon dioxide, trimethylolpropane triacrylate, photoinitiator and silane coupling agent to the second polyurethane prepolymer also includes: Add rosin hydrophobic malic acid glyceryl ester tackifying resin.

11. A pressure-sensitive adhesive, characterized in that: The pressure-sensitive adhesive is prepared by the method for preparing a pressure-sensitive adhesive according to any one of claims 8 to 10.

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