High-weather-resistance polyacrylate emulsion pressure-sensitive adhesive as well as preparation method and application thereof

Abstract

The invention relates to the technical field of adhesives for surface protection films, in particular to a high-weather-resistance polyacrylate emulsion pressure-sensitive adhesive as well as a preparation method and application thereof. The high-weather-resistance polyacrylate emulsion pressure-sensitive adhesive comprises an acrylate monomer, an organic silicon modifier, a chain transfer agent, a modified polymerizable emulsifier, an initiator, a pH regulator, a pH buffering agent and water, the modified polymerizable emulsifier is mainly prepared from sulfonate modified toluene diisocynate, trimethylolpropane and an acrylate modifier. The modified polymerizable emulsifier is introduced into the polyacrylate emulsion pressure-sensitive adhesive, and polymerizable double bonds and isocyanate groups exist, so that the polyacrylate emulsion pressure-sensitive adhesive can participate in a polymerization reaction between monomers and is grafted to an acrylate polymer molecular main chain while the emulsification and dispersion effects are ensured, the emulsifier is prevented from being migrated to the surface of a pressure-sensitive adhesive layer, and the adhesion between the pressure-sensitive adhesive layer and the pressure-sensitive adhesive layer is avoided. The water resistance and the aging resistance of the pressure-sensitive adhesive are improved.

Description

Technical Field

[0001] The invention relates to the technical field of adhesives for surface protection films, in particular to a highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive and a preparation method and application thereof. Background Art

[0002] In the field of adhesive technology for surface protection films, polyacrylate emulsion pressure-sensitive adhesive is one of the most important categories. Since surface protection films are often exposed to high temperature, high humidity and sunlight for a long time during transportation or use, it is very easy to have spots and residual adhesive on the surface of the protected material when peeling it off after a long period of application, which seriously affects the actual application performance of the protective film. Especially when the protected material is a polar material such as coated glass, high-gloss acrylic plate, etc., the weather resistance requirements for the surface protection film are higher, and the existing conventional polyacrylate emulsion pressure-sensitive adhesive can no longer meet the needs of the rapidly developing surface protection film market.

[0003] In view of this, the present invention is proposed. Summary of the invention

[0004] One object of the present invention is to provide a highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive having good cohesive strength, stable peeling force, and excellent water resistance and aging resistance.

[0005] Another object of the present invention is to provide a method for preparing a highly weather-resistant polyacrylic acid emulsion pressure-sensitive adhesive.

[0006] Another object of the present invention is to provide an application of a highly weather-resistant polyacrylic acid emulsion pressure-sensitive adhesive in the preparation of a surface protection film.

[0007] In order to achieve the above-mentioned object of the present invention, the present invention provides a highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive, comprising the following components in parts by weight:

[0008] 88-105 parts of acrylate monomer, 0.5-1.5 parts of organosilicon modifier, 0.01-0.03 parts of chain transfer agent, 0.5-2.5 parts of modified polymerizable emulsifier, 0.1-0.8 parts of initiator, 0.5-1 parts of pH adjuster, 0.01-0.2 parts of pH buffer and 100-120 parts of water;

[0009] The modified polymerizable emulsifier is mainly prepared from sulfonate-modified toluene diisocyanate, trimethylolpropane and an acrylate modifier.

[0010] In a specific embodiment of the present invention, the acrylate modifier includes at least one of hydroxyethyl acrylate and hydroxypropyl acrylate.

[0011] In a specific embodiment of the present invention, the mass ratio of the sulfonate-modified toluene diisocyanate, trimethylolpropane and acrylate modifier is (34-40): (2-6): (30-36).

[0012] In a specific embodiment of the present invention, the modified polymerizable emulsifier further comprises a solvent. Further, the solvent comprises propylene glycol monomethyl ether acetate.

[0013] In a specific embodiment of the present invention, the preparation of the modified polymerizable emulsifier includes: reacting sulfonate-modified toluene diisocyanate with trimethylolpropane in a part of solvent, adding acrylate modifier and the remaining solvent, and stirring the reaction.

[0014] In a specific embodiment of the present invention, the acrylic acid ester monomers include the following components by weight: 84-90 parts of acrylic acid ester soft monomers, 2-8 parts of acrylic acid ester hard monomers, 0.5-2 parts of functional monomers and 1.5-3.5 parts of internal cross-linking monomers.

[0015] In a specific embodiment of the present invention, the acrylic acid ester soft monomer includes at least one of ethyl acrylate, butyl acrylate and isooctyl acrylate.

[0016] In a specific embodiment of the present invention, the acrylic acid ester hard monomer includes at least one of methyl acrylate, ethyl methacrylate and n-butyl methacrylate.

[0017] In a specific embodiment of the present invention, the functional monomer includes at least one of acrylic acid and methacrylic acid.

[0018] In a specific embodiment of the present invention, the internal cross-linking monomer includes at least one of hydroxymethyl acrylamide and butoxy acrylamide.

[0019] In a specific embodiment of the present invention, the organosilicon modifier includes vinyl silicone oil.

[0020] Another aspect of the present invention provides a method for preparing a highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive, comprising the following steps:

[0021] (a) mixing a portion of water, a portion of a modified polymerizable emulsifier, a portion of an initiator, a portion of a pH buffer, an acrylate monomer, and a chain transfer agent to obtain a pre-emulsion;

[0022] (b) the remaining water, the remaining modified polymerizable emulsifier, and the remaining pH buffer are mixed uniformly, the temperature is raised to 75-80° C., the remaining initiator and 10%-15% of the pre-emulsified liquid are added, and the reaction is stirred for 20-40 minutes;

[0023] (c) uniformly mixing the remaining pre-emulsion and the organosilicon modifier, adding the mixture to the material of step (b), stirring and reacting for more than 1 hour, cooling and adding a pH regulator to obtain a highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive.

[0024] Another aspect of the present invention provides use of any one of the above-mentioned highly weather-resistant polyacrylate emulsion pressure-sensitive adhesives in the preparation of a surface protection film.

[0025] In a specific embodiment of the present invention, the highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive and the aziridine curing agent are uniformly mixed and coated on the surface of the substrate to obtain the surface protection film.

[0026] In a specific embodiment of the present invention, the amount of the aziridine curing agent is 0.2% to 1% of the mass of the high weather-resistant polyacrylate emulsion pressure-sensitive adhesive.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The modified polymerizable emulsifier is introduced into the polyacrylate emulsion pressure-sensitive adhesive of the present invention, and has polymerizable double bonds and isocyanate groups. While ensuring the emulsification and dispersion effect, it can also participate in the polymerization reaction between monomers and be grafted onto the main chain of the acrylic polymer molecule, thereby avoiding the emulsifier from migrating to the surface of the pressure-sensitive adhesive layer, thereby improving the water resistance and aging resistance of the pressure-sensitive adhesive;

[0029] (2) The polyacrylate emulsion pressure-sensitive adhesive of the present invention is added with functional monomers, internal crosslinking monomers and organosilicon modifiers to provide multiple internal crosslinking sites for intramolecular crosslinking, increase the cohesive strength of the polymer, and improve the wettability to the surface of the adhered material, thereby solving the problem of residual glue during peeling;

[0030] (3) The polyacrylate emulsion pressure-sensitive adhesive of the present invention can be used to prepare surface protection films, and can be used to protect the surfaces of polar materials, etc. It can provide good protection for long-term application in high temperature, high humidity, light and other environments, and no residual adhesive will remain after peeling off after long-term application. DETAILED DESCRIPTION

[0031] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments, but it will be appreciated by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work, all belong to the scope of protection of the present invention. If specific conditions are not indicated in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0032] In one aspect, the present invention provides a highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive, comprising the following components in parts by weight:

[0033] 88-105 parts of acrylate monomer, 0.5-1.5 parts of organosilicon modifier, 0.01-0.03 parts of chain transfer agent, 0.5-2.5 parts of modified polymerizable emulsifier, 0.1-0.8 parts of initiator, 0.5-1 parts of pH adjuster, 0.01-0.2 parts of pH buffer and 100-120 parts of water;

[0034] The modified polymerizable emulsifier is mainly prepared from sulfonate-modified toluene diisocyanate, trimethylolpropane and acrylate modifier.

[0035] The modified polymerizable emulsifier is introduced into the polyacrylate emulsion pressure-sensitive adhesive of the present invention, and has polymerizable double bonds and isocyanate groups. While ensuring the emulsification and dispersion effect, it can also participate in the polymerization reaction between monomers and be grafted onto the main chain of the acrylic polymer molecule, thereby avoiding the emulsifier from migrating to the surface of the pressure-sensitive adhesive layer and improving the water resistance and aging resistance of the pressure-sensitive adhesive.

[0036] For example, in different embodiments, the amounts of each component may be as follows by weight:

[0037] The amount of the acrylic acid ester monomer can be 88 parts, 90 parts, 92 parts, 95 parts, 98 parts, 100 parts, 102 parts, 105 parts or a range consisting of any two of them;

[0038] The amount of the organosilicon modifier can be 0.5 parts, 0.6 parts, 0.8 parts, 1 parts, 1.2 parts, 1.5 parts or a range consisting of any two of them;

[0039] The amount of the chain transfer agent can be 0.01 part, 0.015 part, 0.02 part, 0.025 part, 0.03 part or any two thereof;

[0040] The amount of the modified polymerizable emulsifier can be 0.5 parts, 0.8 parts, 1 parts, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts or a range consisting of any two of them;

[0041] The amount of the initiator can be 0.1 part, 0.3 part, 0.5 part, 0.6 part, 0.8 part or a range consisting of any two thereof;

[0042] The amount of the pH adjuster can be 0.5 parts, 0.6 parts, 0.8 parts, 1 part or a range consisting of any two of them;

[0043] The amount of the pH buffer can be 0.01 part, 0.05 part, 0.1 part, 0.15 part, 0.2 part or a range consisting of any two thereof;

[0044] The amount of water can be 100 parts, 105 parts, 110 parts, 115 parts, 120 parts or a range consisting of any two of them.

[0045] In a specific embodiment of the present invention, the acrylate modifier includes at least one of hydroxyethyl acrylate and hydroxypropyl acrylate.

[0046] In a specific embodiment of the present invention, the mass ratio of sulfonate-modified toluene diisocyanate, trimethylolpropane and acrylate modifier is (34-40): (2-6): (30-36).

[0047] For example, in different embodiments, the mass ratio of sulfonate modified toluene diisocyanate and trimethylolpropane can be 34:2, 34:3, 34:4, 34:6, 36:2, 36:3, 36:4, 36:6, 38:2, 38:3, 38:4, 38:6, 40:2, 40:3, 40:4, 40:6 or a range consisting of any two thereof; the mass ratio of trimethylolpropane and acrylate modifier can be 2:30, 2:33, 2:36, 4:30, 4:33, 4:36, 6:30, 6:33, 6:36 or a range consisting of any two thereof.

[0048] Adjusting the mass ratio of sulfonate-modified toluene diisocyanate, trimethylolpropane and acrylate modifier within the above range is more conducive to giving full play to the emulsification and dispersion effect of the modified polymerizable emulsifier, and effectively grafting it onto the polymer main chain, avoiding the migration of the emulsifier, improving the water resistance and aging resistance, and avoiding spots and residual glue. Among them, the sulfonate-modified toluene diisocyanate can use the existing water-based TDI modified by sulfonate.

[0049] In a specific embodiment of the present invention, the modified polymerizable emulsifier further comprises a solvent. Further, the solvent comprises propylene glycol monomethyl ether acetate.

[0050] In actual operation, the amount of propylene glycol monomethyl ether acetate can be 0.2 to 0.5 times the mass sum of sulfonate-modified toluene diisocyanate, trimethylolpropane and acrylate modifier, for example, 0.2 times, 0.3 times, 0.4 times, 0.5 times, etc.

[0051] In a specific embodiment of the present invention, the preparation of the modified polymerizable emulsifier includes: reacting sulfonate-modified toluene diisocyanate with trimethylolpropane in a part of solvent, adding acrylate modifier and the remaining solvent, and stirring the reaction.

[0052] In actual operation, the partial solvent may be 45% to 55% solvent.

[0053] In some embodiments, the reaction with trimethylolpropane may include: stirring and reacting at 50-60° C. for 2-3 hours, and then heating to 75-80° C. for 4-5 hours.

[0054] In some embodiments, the material after the reaction with trimethylolpropane is first cooled to 50-60° C., and then the acrylate modifier and the remaining solvent are added, and then stirred to react for 2-3 hours.

[0055] In a specific embodiment of the present invention, the acrylic acid ester monomer includes the following components by weight: 84-90 parts of acrylic acid ester soft monomer, 2-8 parts of acrylic acid ester hard monomer, 0.5-2 parts of functional monomer and 1.5-3.5 parts of internal cross-linking monomer.

[0056] In a specific embodiment of the present invention, the acrylic acid ester soft monomer includes at least one of ethyl acrylate, butyl acrylate and isooctyl acrylate. Among the acrylic acid ester monomers, the amount of the acrylic acid ester soft monomer can be 84 parts, 85 parts, 86 parts, 88 parts, 90 parts or a range consisting of any two of them.

[0057] In a specific embodiment of the present invention, the acrylate hard monomer includes at least one of methyl acrylate, ethyl methacrylate and n-butyl methacrylate. Among the acrylate monomers, the amount of the acrylate hard monomer can be 2 parts, 4 parts, 5 parts, 6 parts, 8 parts or a range consisting of any two of them.

[0058] In a specific embodiment of the present invention, the functional monomer includes at least one of acrylic acid and methacrylic acid. In the acrylic ester monomer, the amount of the functional monomer can be 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts or any two of them.

[0059] In a specific embodiment of the present invention, the internal crosslinking monomer includes at least one of hydroxymethyl acrylamide and butoxy acrylamide. Among the acrylic ester monomers, the amount of the internal crosslinking monomer can be 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3 parts, 3.2 parts, 3.5 parts or a range consisting of any two of them.

[0060] In a specific embodiment of the present invention, the organosilicon modifier includes vinyl silicone oil. Adding an appropriate amount of vinyl silicone oil to the polyacrylic emulsion pressure-sensitive adhesive of the present invention not only provides internal cross-linking points and increases cohesive strength, but also improves wettability on the surface of the adhered material, which helps to solve problems such as residual adhesive and spot shadows.

[0061] In a specific embodiment of the present invention, the chain transfer agent includes at least one of n-dodecyl mercaptan, tert-dodecyl mercaptan and octadecyl mercaptan.

[0062] In a specific embodiment of the present invention, the initiator includes a water-soluble initiator, including but not limited to persulfate, hydroperoxide, etc. For example, it can be ammonium persulfate, potassium persulfate, sodium persulfate, tert-butyl peroxyneoheptanoate, etc.

[0063] In a specific embodiment of the present invention, the pH adjuster includes aqueous ammonia.

[0064] In a specific embodiment of the present invention, the pH buffer comprises at least one of sodium bicarbonate, ammonium bicarbonate, sodium dihydrogen phosphate and sodium acetate.

[0065] Other conventional additives, such as defoamers, antistatic agents and the like, may also be added to the polyacrylate emulsion pressure-sensitive adhesive of the present invention.

[0066] Another aspect of the present invention provides a method for preparing a highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive, comprising the following steps:

[0067] (a) mixing a portion of water, a portion of a modified polymerizable emulsifier, a portion of an initiator, a portion of a pH buffer, an acrylate monomer, and a chain transfer agent to obtain a pre-emulsion;

[0068] (b) the remaining water, the remaining modified polymerizable emulsifier, and the remaining pH buffer are mixed uniformly, the temperature is raised to 75-80° C., the remaining initiator and 10%-15% of the pre-emulsified liquid are added, and the reaction is stirred for 20-40 minutes;

[0069] (c) uniformly mixing the remaining pre-emulsion and the organosilicon modifier, adding the mixture to the material of step (b), stirring and reacting for more than 1 hour, cooling and adding a pH regulator to obtain a highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive.

[0070] The use of the above process to prepare polyacrylate emulsion pressure-sensitive adhesive is more conducive to the preparation of highly stable emulsions, which can improve production and product quality.

[0071] In some embodiments, in step (a), when preparing the pre-emulsion, 45% to 55% of water, 55% to 65% of the modified polymerizable emulsifier, 40% to 50% of the initiator, and 45% to 55% of the pH buffer can be used.

[0072] In some embodiments, in step (c), the remaining amount of pre-emulsion is mixed with the organosilicon modifier and then added to the material of step (b) in a dropwise manner within 3 to 4 hours.

[0073] Another aspect of the present invention provides use of any one of the above-mentioned highly weather-resistant polyacrylate emulsion pressure-sensitive adhesives in the preparation of a surface protection film.

[0074] In a specific embodiment of the present invention, a highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive and an aziridine curing agent are uniformly mixed and coated on the surface of a substrate to obtain a surface protective film.

[0075] The coating method is not limited, and roller coating, blade coating or dip coating can be used. The coating thickness of the pressure-sensitive adhesive can be selected according to actual needs, for example, it can be 10 to 25 μm, but it is not limited thereto. After coating, it is dried and rolled up to obtain a surface protection film.

[0076] In some embodiments, the substrate may be a polyethylene-based film, but is not limited thereto.

[0077] In a specific embodiment of the present invention, the amount of aziridine curing agent used is 0.2% to 1% of the mass of the high weather-resistant polyacrylate emulsion pressure-sensitive adhesive.

[0078] For example, in different embodiments, the amount of the aziridine curing agent can be 0.2%, 0.4%, 0.6%, 0.8%, 1% of the mass of the high weather-resistant polyacrylate emulsion pressure-sensitive adhesive, or a range consisting of any two thereof.

[0079] The sulfonate-modified toluene diisocyanate used in the following specific embodiments can be water-based TDI purchased from Foshan Jingxin Huiming Technology Co., Ltd., model SSTD-80 diisocyanate, but it is not limited thereto, and other sulfonate-modified toluene diisocyanates can be used.

[0080] Example 1

[0081] The present embodiment provides a highly weather-resistant polyacrylic emulsion pressure-sensitive adhesive, comprising the following components in parts by weight: 86 parts of butyl acrylate, 6 parts of n-butyl methacrylate, 1.5 parts of acrylic acid, 2.5 parts of butoxyacrylamide, 1 part of vinyl silicone oil, 0.02 parts of n-dodecyl mercaptan, 2 parts of a modified polymerizable emulsifier, 0.6 parts of ammonium persulfate, 0.6 parts of ammonia water (mass fraction of 25% to 28%, analytical grade), 0.06 parts of sodium bicarbonate, and 110 parts of deionized water.

[0082] The modified polymerizable emulsifier is prepared from sulfonate-modified toluene diisocyanate, trimethylolpropane, hydroxyethyl acrylate and propylene glycol monomethyl ether acetate in a mass ratio of 38:4:32:28; the specific preparation method comprises: adding sulfonate-modified toluene diisocyanate and 50% of propylene glycol monomethyl ether acetate into a reaction bottle, starting stirring, heating to 55-60°C, adding trimethylolpropane, stirring and reacting for 2 hours, and then heating to 75-80°C and reacting for 4 hours; then cooling the material to 55-60°C, adding hydroxyethyl acrylate and the remainder of propylene glycol monomethyl ether acetate, stirring and reacting for 2 hours, discharging the material, and obtaining the modified polymerizable emulsifier.

[0083] The preparation method of the highly weather-resistant polyacrylic acid emulsion pressure-sensitive adhesive of this embodiment comprises the following steps:

[0084] (1) Weigh 50% of deionized water, 60% of a modified polymerizable emulsifier, 50% of an initiator, 50% of a pH buffer, all monomers, and a chain transfer agent according to a ratio, mix them, and stir them evenly at 35 to 40° C. to prepare a pre-emulsion.

[0085] (2) Take 88% of the pre-emulsion prepared in step (1) and mix with vinyl silicone oil, stir evenly and set aside.

[0086] (3) Weigh the remaining amount of deionized water, the remaining amount of modified polymerizable emulsifier, and the remaining amount of pH buffer in a reaction kettle according to the ratio, mix them evenly, stir and heat to 75-80° C., add the remaining amount of initiator and 12% of the pre-emulsion prepared in step (1) into the reaction kettle; then heat to 85-89° C., stir and react for 30 minutes, then drop the material of step (2) into the reaction kettle within 3 hours, and after the dropwise addition is completed, stir and react at 80-85° C. for 2 hours.

[0087] (4) Cooling the material in step (3) to 40-45° C., adding a pH adjuster and stirring for 30 min, filtering the material to obtain a highly weather-resistant polyacrylic acid emulsion pressure-sensitive adhesive.

[0088] This embodiment also provides a method for preparing a surface protection film, comprising:

[0089] Aziridine curing agent is added to the highly weather-resistant polyacrylic acid emulsion pressure-sensitive adhesive, and the mixture is uniformly mixed to obtain a rubber compound; the rubber compound is coated on the surface of a 98 μm thick PE base film with a dry adhesive thickness of 17±1 μm, and after drying, the composite film is rolled up to obtain a surface protective film. The amount of the aziridine curing agent used is 0.5 wt% of the highly weather-resistant polyacrylic acid emulsion pressure-sensitive adhesive.

[0090] Example 2

[0091] This embodiment refers to the high weather resistant polyacrylic emulsion pressure sensitive adhesive, surface protective film and preparation method of Example 1, with the only difference being: the raw material of the modified polymerizable emulsifier is different, the raw material composition of the high weather resistant polyacrylic emulsion pressure sensitive adhesive is different, and the amount of aziridine curing agent used is different.

[0092] In this embodiment, the modified polymerizable emulsifier is prepared from sulfonate-modified toluene diisocyanate, trimethylolpropane, hydroxypropyl acrylate and propylene glycol monomethyl ether acetate in a mass ratio of 37:3:34:26; the preparation method is the same as that in Example 1.

[0093] In this embodiment, the highly weather-resistant polyacrylic emulsion pressure-sensitive adhesive includes the following components in parts by weight: 88 parts of isooctyl acrylate, 7 parts of methyl acrylate, 1.2 parts of acrylic acid, 2 parts of hydroxymethyl acrylamide, 0.8 parts of vinyl silicone oil, 0.02 parts of tert-dodecyl mercaptan, 2.5 parts of modified polymerizable emulsifier, 0.6 parts of ammonium persulfate, 0.7 parts of ammonia water (mass fraction of 25% to 28%, analytical grade), 0.08 parts of sodium bicarbonate and 100 parts of deionized water; the preparation method is the same as that in Example 1.

[0094] In this embodiment, in the preparation of the surface protection film, the amount of aziridine curing agent used is 0.6wt% of the high weather-resistant polyacrylic acid emulsion pressure-sensitive adhesive; the preparation method is the same as that of Example 1.

[0095] Example 3

[0096] This embodiment refers to the high weather resistant polyacrylic emulsion pressure sensitive adhesive, surface protective film and preparation method of Example 1, with the only difference being: the raw material of the modified polymerizable emulsifier is different, the raw material composition of the high weather resistant polyacrylic emulsion pressure sensitive adhesive is different, and the amount of aziridine curing agent used is different.

[0097] In this embodiment, the modified polymerizable emulsifier is prepared from sulfonate-modified toluene diisocyanate, trimethylolpropane, hydroxyethyl acrylate and propylene glycol monomethyl ether acetate in a mass ratio of 39:5:33:30; the preparation method is the same as that in Example 1.

[0098] In this embodiment, the high weather-resistant polyacrylic emulsion pressure-sensitive adhesive includes the following components in parts by weight: 89 parts of butyl acrylate, 5 parts of methyl acrylate, 1.6 parts of methacrylic acid, 3 parts of butoxyacrylamide, 1.2 parts of vinyl silicon, 0.03 parts of n-dodecyl mercaptan, 1.5 parts of modified polymerizable emulsifier, 0.7 parts of ammonium persulfate, 0.8 parts of ammonia water (mass fraction of 25% to 28%, analytical grade), 0.1 parts of sodium bicarbonate and 120 parts of deionized water; the preparation method is the same as that in Example 1.

[0099] In this embodiment, in the preparation of the surface protection film, the amount of aziridine curing agent used is 0.55wt% of the high weather-resistant polyacrylic emulsion pressure-sensitive adhesive; the preparation method is the same as in Example 1.

[0100] Example 4

[0101] This embodiment refers to the high weather resistant polyacrylic emulsion pressure sensitive adhesive, surface protective film and preparation method of Example 1, with the only difference being: the raw material of the modified polymerizable emulsifier is different, the raw material composition of the high weather resistant polyacrylic emulsion pressure sensitive adhesive is different, and the amount of aziridine curing agent used is different.

[0102] In this embodiment, the modified polymerizable emulsifier is prepared from sulfonate-modified toluene diisocyanate, trimethylolpropane, hydroxypropyl acrylate and propylene glycol monomethyl ether acetate in a mass ratio of 36:6:35:24; the preparation method is the same as that in Example 1.

[0103] In this embodiment, the high weather-resistant polyacrylic emulsion pressure-sensitive adhesive includes the following components in parts by weight: 88 parts of isooctyl acrylate, 5 parts of ethyl methacrylate, 1.2 parts of acrylic acid, 3 parts of hydroxymethyl acrylamide, 1.4 parts of vinyl silicon, 0.02 parts of n-dodecyl mercaptan, 2.5 parts of modified polymerizable emulsifier, 0.7 parts of ammonium persulfate, 0.6 parts of ammonia water (mass fraction of 25% to 28%, analytical grade), 0.08 parts of sodium bicarbonate and 100 parts of deionized water; the preparation method is the same as that in Example 1.

[0104] In this embodiment, in the preparation of the surface protection film, the amount of aziridine curing agent used is 0.65wt% of the high weather-resistant polyacrylic acid emulsion pressure-sensitive adhesive; the preparation method is the same as that of Example 1.

[0105] Example 5

[0106] This embodiment refers to the highly weather-resistant polyacrylic emulsion pressure-sensitive adhesive, surface protection film and preparation method of Example 3, with the only difference being that the raw materials of the modified polymerizable emulsifier are different.

[0107] In this embodiment, the modified polymerizable emulsifier is prepared from sulfonate-modified toluene diisocyanate, trimethylolpropane, hydroxyethyl acrylate and propylene glycol monomethyl ether acetate in a mass ratio of 33:6:36:30; the preparation method is the same as that in Example 1.

[0108] Example 6

[0109] This embodiment refers to the highly weather-resistant polyacrylic emulsion pressure-sensitive adhesive, surface protection film and preparation method of Example 3, with the only difference being that the raw materials of the modified polymerizable emulsifier are different.

[0110] In this embodiment, the modified polymerizable emulsifier is prepared from sulfonate-modified toluene diisocyanate, trimethylolpropane, hydroxyethyl acrylate and propylene glycol monomethyl ether acetate in a mass ratio of 41:4:30:30; the preparation method is the same as that in Example 1.

[0111] Example 7

[0112] This embodiment refers to the highly weather-resistant polyacrylic emulsion pressure-sensitive adhesive, surface protection film and preparation method of Example 3, with the only difference being that the raw materials of the modified polymerizable emulsifier are different.

[0113] In this embodiment, the modified polymerizable emulsifier is prepared from sulfonate-modified toluene diisocyanate, trimethylolpropane, hydroxyethyl acrylate and propylene glycol monomethyl ether acetate in a mass ratio of 39:6:29:30; the preparation method is the same as that in Example 1.

[0114] Example 8

[0115] This embodiment refers to the highly weather-resistant polyacrylic emulsion pressure-sensitive adhesive, surface protection film and preparation method of Example 3, with the only difference being that the raw materials of the modified polymerizable emulsifier are different.

[0116] In this embodiment, the modified polymerizable emulsifier is prepared from sulfonate-modified toluene diisocyanate, trimethylolpropane, hydroxyethyl acrylate and propylene glycol monomethyl ether acetate in a mass ratio of 36:2:38:30; the preparation method is the same as that in Example 1.

[0117] Comparative Example 1

[0118] Comparative Example 1 refers to the highly weather-resistant polyacrylic emulsion pressure-sensitive adhesive, surface protection film and preparation method of Example 3, except that an equal weight of composite emulsifier is used to replace the modified polymerizable emulsifier in Example 3.

[0119] The composite emulsifier used in Comparative Example 1 is sodium dodecylbenzene sulfonate and nonylphenol polyoxyethylene ether in a mass ratio of 2:3.

[0120] Comparative Example 2

[0121] Comparative Example 2 refers to the highly weather-resistant polyacrylic emulsion pressure-sensitive adhesive, surface protection film and preparation method of Example 3, except that an equal weight of composite emulsifier is used to replace the modified polymerizable emulsifier in Example 3.

[0122] The composite emulsifier used in Comparative Example 2 is sodium allyl alkyl ether sulfonate and allyloxy polyoxyethylene ether in a mass ratio of 2:1.

[0123] Comparative Example 3

[0124] Comparative Example 3 refers to the high weather resistant polyacrylic emulsion pressure sensitive adhesive, surface protection film and preparation method of Example 3, except that: the raw material composition of the high weather resistant polyacrylic emulsion pressure sensitive adhesive is different.

[0125] In the polyacrylic acid emulsion pressure-sensitive adhesive of Comparative Example 3, no vinyl silicone oil is added.

[0126] Comparative Example 4

[0127] Comparative Example 4 refers to the high weather resistant polyacrylic emulsion pressure sensitive adhesive, surface protection film and preparation method of Example 3, except that: the raw material composition of the high weather resistant polyacrylic emulsion pressure sensitive adhesive is different.

[0128] The polyacrylic acid emulsion pressure-sensitive adhesive of Comparative Example 4 includes the following components in parts by weight: 89 parts of butyl acrylate, 5 parts of methyl acrylate, 1.6 parts of methacrylic acid, 3 parts of butoxyacrylamide, 2 parts of vinyl silicone oil, 0.03 parts of n-dodecyl mercaptan, 1.5 parts of modified polymerizable emulsifier, 0.7 parts of ammonium persulfate, 0.8 parts of ammonia water (mass fraction of 25% to 28%, analytical grade), 0.1 parts of sodium bicarbonate and 120 parts of deionized water; the preparation method is the same as that of Example 1.

[0129] Experimental example

[0130] The surface protection films prepared in different embodiments and comparative examples were cut into predetermined sizes as test samples, and their peeling force, high temperature and high humidity aging, water resistance and outdoor aging performance were compared and tested. The test methods are as follows, and the test results are shown in Table 1.

[0131] Peel force test: refer to GB / T 2792-2017 standard method to test its 30min peel force and 24h peel force;

[0132] High temperature and high humidity aging test: Cut the protective film into a predetermined size, stick it on the test coated glass plate, place it in a 70℃ / 95%RH constant temperature and humidity chamber for 48 hours, take it out, tear off the protective film on the coated glass plate, and observe the residual glue and spots;

[0133] Water resistance test: spray water evenly on the coated glass surface and then apply the film. Wrap the coated glass with a wet towel and then wrap it with the film. Place it in a 120℃ oven for 1 hour, take it out, tear off the protective film on the coated glass, and observe the residual glue.

[0134] Outdoor aging test: After the coated glass is filmed, place it outdoors for 1 month, remove the protective film on the coated glass plate, and observe the residual glue.

[0135] Table 1 Performance test results of different surface protection films

[0136]

[0137]

[0138] From the above test results, it can be seen that the polyacrylate emulsion pressure-sensitive adhesive of the present invention has stable peeling force, good cohesive strength, small peeling force increase during use, excellent water resistance and aging resistance, and is particularly suitable for surface protective films of polar materials with high weather resistance requirements.

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. Highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive, characterized in that: It includes the following components by weight: 88-105 parts of acrylate monomer, 0.5-1.5 parts of organosilicon modifier, 0.01-0.03 parts of chain transfer agent, 0.5-2.5 parts of modified polymerizable emulsifier, 0.1-0.8 parts of initiator, 0.5-1 parts of pH adjuster, 0.01-0.2 parts of pH buffer and 100-120 parts of water; The modified polymerizable emulsifier is mainly prepared from sulfonate-modified toluene diisocyanate, trimethylolpropane and an acrylate modifier.

2. The highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive according to claim 1, characterized in that: The acrylate modifier includes at least one of hydroxyethyl acrylate and hydroxypropyl acrylate.

3. The highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive according to claim 1, characterized in that: The mass ratio of the sulfonate-modified toluene diisocyanate, trimethylolpropane and acrylate modifier is (34-40): (2-6): (30-36).

4. The highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive according to claim 1, characterized in that: The modified polymerizable emulsifier also includes a solvent; Preferably, the solvent comprises propylene glycol monomethyl ether acetate.

5. The highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive according to claim 1, characterized in that: The preparation of the modified polymerizable emulsifier comprises: reacting sulfonate-modified toluene diisocyanate with trimethylolpropane in a part of solvent, adding acrylate modifier and the remaining solvent, and stirring for reaction.

6. The highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive according to claim 1, characterized in that: The acrylic acid ester monomers include the following components by weight: 84-90 parts of acrylic acid ester soft monomers, 2-8 parts of acrylic acid ester hard monomers, 0.5-2 parts of functional monomers and 1.5-3.5 parts of internal cross-linking monomers; Preferably, the acrylic ester soft monomer includes at least one of ethyl acrylate, butyl acrylate and isooctyl acrylate; Preferably, the acrylic acid ester hard monomer comprises at least one of methyl acrylate, ethyl methacrylate and n-butyl methacrylate; Preferably, the functional monomer includes at least one of acrylic acid and methacrylic acid; Preferably, the internal cross-linking monomer includes at least one of hydroxymethyl acrylamide and butoxy acrylamide.

7. The highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive according to claim 1, characterized in that: The organosilicon modifier includes vinyl silicone oil.

8. The method for preparing the highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive according to any one of claims 1 to 7, characterized in that: The steps include: (a) mixing a portion of water, a portion of a modified polymerizable emulsifier, a portion of an initiator, a portion of a pH buffer, an acrylate monomer, and a chain transfer agent to obtain a pre-emulsion; (b) the remaining water, the remaining modified polymerizable emulsifier, and the remaining pH buffer are mixed uniformly, the temperature is raised to 75-80° C., the remaining initiator and 10%-15% of the pre-emulsified liquid are added, and the reaction is stirred for 20-40 minutes; (c) uniformly mixing the remaining pre-emulsion and the organosilicon modifier, adding the mixture to the material of step (b), stirring and reacting for more than 1 hour, cooling and adding a pH regulator to obtain a highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive.

9. Use of the highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive according to any one of claims 1 to 7 in the preparation of surface protection films.

10. The use according to claim 9, characterized in that: The highly weather-resistant polyacrylate emulsion pressure-sensitive adhesive and the aziridine curing agent are uniformly mixed and coated on the surface of the substrate to obtain the surface protective film; Preferably, the amount of the aziridine curing agent used is 0.2% to 1% of the mass of the high weather-resistant polyacrylate emulsion pressure-sensitive adhesive.

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