Carboxylated acrylate aqueous dispersions, process for their preparation and protective films for aluminium profiles

Abstract

The application discloses a kind of carboxyl acrylate water dispersion, its preparation method and aluminium profile protective film, the carboxyl acrylate water dispersion, by mass fraction, including following raw material components: acrylate monomer 85~98 parts, functional monomer 2~3 parts, internal crosslinking monomer 0.05~1.5 parts, chain transfer agent 0.1~0.5 parts, reactive emulsifier 0.33~1 parts, anionic emulsifier 0.09~0.15 parts, initiator 0.4~0.8 parts, pH buffering agent 0.1~0.2, deionized water 43~50 parts;Wherein, functional monomer is at least one in acrylic acid, methacrylic acid and hydroxyethyl acrylate;Internal crosslinking monomer is at least one in N-hydroxymethyl acrylamide and butoxy acrylamide.The carboxyl acrylate water dispersion of the application has high solid content, low viscosity and good adhesive property, and can be used for preparing aluminium profile surface protective film.

Description

Technical Field

[0001] This invention belongs to the field of acrylic emulsion technology, specifically relating to a carboxyacrylate aqueous dispersion, its preparation method, and a protective film for aluminum profiles. Background Technology

[0002] High-solids-content carboxyacrylate aqueous dispersions have become an important development direction in the coatings and adhesives industry due to their environmental friendliness, high efficiency and multifunctionality.

[0003] Currently, the common high-solids-content carboxylated acrylate aqueous dispersions on the market have a solids content of around 60%. Although they can achieve the characteristics of high solids content and low viscosity, their application scenarios are limited. For example, in the field of adhesive technology for protective films on aluminum profiles, they have high peel strength growth and are extremely prone to cohesive failure under high temperature and high humidity environments. In particular, when the substrate of the protective film is PVC film, polyester film, or pretreated polyethylene and polypropylene film, the requirements for its anti-plasticization and adhesion are high. Conventional high-solids-content carboxylated acrylate aqueous dispersions can no longer fully meet the above application conditions.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a high-solids-content carboxylated acrylate aqueous dispersion, which has high solids content, low viscosity and good adhesion properties, and can be used to prepare a protective film on the surface of aluminum profiles.

[0006] To achieve the above objectives, a specific embodiment of the present invention provides the following technical solution: a carboxyacrylate aqueous dispersion, wherein the raw materials of the carboxyacrylate aqueous dispersion include a pH adjuster for adjusting the pH value during the preparation process, and the carboxyacrylate aqueous dispersion comprises, by mass parts, the following raw material components: 85-98 parts of acrylate monomer, 2-3 parts of functional monomer, 0.05-1.5 parts of internal crosslinking monomer, 0.1-0.5 parts of chain transfer agent, 0.33-1 parts of reactive emulsifier, 0.09-0.15 parts of anionic emulsifier, 0.4-0.8 parts of initiator, 0.1-0.2 parts of pH buffer, and 43-50 parts of deionized water;

[0007] The functional monomer is at least one of acrylic acid, methacrylic acid and hydroxyethyl acrylate; the internal crosslinking monomer is at least one of N-hydroxymethylacrylamide and butoxyacrylamide.

[0008] In one or more embodiments of the present invention, the acrylate monomers include soft acrylate monomers and hard acrylate monomers.

[0009] In one or more embodiments of the present invention, the mass ratio of the acrylate soft monomer to the acrylate hard monomer is 1:(0.05~0.2).

[0010] In one or more embodiments of the present invention, the acrylate soft monomer is at least one selected from ethyl acrylate, butyl acrylate and isooctyl acrylate;

[0011] The acrylate hard monomer is at least one of methyl acrylate, methyl methacrylate, ethyl methacrylate, and n-butyl methacrylate.

[0012] In one or more embodiments of the present invention, the chain transfer agent is at least one of n-dodecyl mercaptan, tert-dodecyl mercaptan, and octadecyl mercaptan;

[0013] The reactive emulsifier is at least one of sodium acrylamide isopropyl sulfonate, sodium monoester of alcohol polyether sulfosuccinate, and sodium allyl alkyl ether sulfonate.

[0014] In one or more embodiments of the present invention, the anionic emulsifier is at least one of sodium dodecylbenzenesulfonate, sodium dodecyl diphenyl ether disulfonate, and sodium alkyl succinate disulfonate;

[0015] The initiator is at least one of ammonium persulfate and potassium persulfate.

[0016] In one or more embodiments of the present invention, the pH adjuster is ammonia; the pH buffer is ammonium bicarbonate.

[0017] A specific embodiment of the present invention also provides a method for preparing the carboxyacrylate aqueous dispersion as described above, comprising the following steps:

[0018] The acrylate monomer, functional monomer, internal crosslinking monomer, chain transfer agent, 35%~50% deionized water, 55%~80% reactive emulsifier, 33%~50% initiator, and 40%~60% pH buffer are stirred and mixed evenly to obtain a pre-emulsion.

[0019] The remaining deionized water, 16%~26% of reactive emulsifier, anionic emulsifier, and remaining pH buffer are mixed and stirred, and then heated to 82°C. The remaining initiator is added, and the mixture is stirred and stirred until homogeneous to obtain the reaction base solution.

[0020] Under conditions of 80~82℃, the pre-emulsion is added dropwise to the reaction base liquid. 4%~7% of the total amount of pre-emulsion is added dropwise in the first 10 minutes, followed by 19%~29% of the total amount of pre-emulsion in the next 20 minutes. Then, the remaining reactive emulsifier is added. After the reactive emulsifier is added, 4%~9% of the total amount of pre-emulsion is added dropwise in the first 10 minutes, followed by the remaining pre-emulsion in the next 60~80 minutes. The temperature is then raised to 88℃~90℃ and held for 30 minutes to obtain the pre-product.

[0021] After cooling the preproduct to 40℃~50℃, a pH adjuster was added, and the mixture was stirred until homogeneous to obtain the carboxyacrylate aqueous dispersion.

[0022] A specific embodiment of the present invention also provides an aluminum profile protective film, including a substrate and an adhesive film disposed on the substrate, wherein the raw materials of the adhesive film include the carboxyacrylate aqueous dispersion and the curing agent as described above.

[0023] Compared with the prior art, the carboxyacrylate aqueous dispersion of the present invention has good adhesive properties through the compounding design of the raw materials in the formulation, and can adhere well to plasticized and unplasticized PVC films, polyester films, and electrically pretreated polyethylene and polypropylene films without adhesive accelerators. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 The multi-peak size distribution diagram of the carboxyacrylate aqueous dispersion in Example 1 of the present invention was obtained by testing with a 90 Plus Pals particle size analyzer. Detailed Implementation

[0026] To enable those skilled in the art to better understand the technical solutions in this disclosure, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this disclosure.

[0027] An example of the carboxyacrylate aqueous dispersion of the present invention includes a pH adjuster for adjusting the pH value during the preparation process. The carboxyacrylate aqueous dispersion comprises, by mass parts: 85-98 parts acrylate monomer, 2-3 parts functional monomer, 0.05-1.5 parts internal crosslinking monomer, 0.1-0.5 parts chain transfer agent, 0.33-1 part reactive emulsifier, 0.09-0.15 parts anionic emulsifier, 0.4-0.8 parts initiator, 0.1-0.2 parts pH buffer, and 43-50 parts deionized water; wherein the functional monomer is at least one of acrylic acid, methacrylic acid, and hydroxyethyl acrylate; and the internal crosslinking monomer is at least one of N-hydroxymethylacrylamide and butoxyacrylamide.

[0028] It is understood that the carboxyacrylate aqueous dispersion of the present invention has good adhesive properties through the compounding design of the raw materials in the formulation, and can adhere well to plasticized and unplasticized PVC films, polyester films, and electrically pretreated polyethylene and polypropylene films without adhesive accelerators, thus having the advantage of wide applicability.

[0029] The carboxyacrylate aqueous dispersion of this invention is a high-solids-content carboxyacrylate emulsion. Generally, in acrylic emulsions, the higher the solids content, the higher the viscosity. However, in practice, acrylic emulsions often need to have both high solids content and low viscosity to facilitate subsequent curing and film formation. High-solids-content emulsions not only significantly reduce the amount of water that needs to be evaporated during the later film formation process, improving production efficiency and reducing curing energy consumption, but also facilitate transportation. Furthermore, high-solids-content emulsions can enable adhesives to achieve superior performance.

[0030] While existing carboxyacrylate aqueous dispersions can achieve a solid content of around 60% (typically around 59%~61%) and possess low viscosity, current formulations and processes either cannot further increase the solid content of carboxyacrylate aqueous dispersions, or simultaneously increase both solid content and viscosity, thus limiting their application range. However, the carboxyacrylate aqueous dispersion of this invention, through improvements in the preparation method and the combination of formulation and raw material design, can achieve a solid content greater than 69% while maintaining low viscosity. Furthermore, it can also be applied to the field of adhesives for protective films on aluminum profiles.

[0031] The carboxyacrylate aqueous dispersion of the present invention can be used to prepare adhesive films. The adhesive film is obtained by mixing the carboxyacrylate aqueous dispersion with a curing agent and other additives (such as defoamers) and then curing. The curing agent, other additives and curing process are all prior art.

[0032] Specifically, the acrylate monomers include soft acrylate monomers and hard acrylate monomers. Soft monomers have flexible molecular chains and strong chain segment mobility, resulting in a highly elastic polymer at room temperature. The soft polymer chains more easily contact the surface of the adherend and generate intermolecular forces, thus providing initial tack. Hard monomers have rigid molecular chains and difficult chain segment movement, making the polymer harder and more brittle. Hard monomers act like the steel reinforcement in a building, forming "physical cross-linking points" within the polymer, significantly improving the strength, tensile strength, and scratch resistance of the adhesive film.

[0033] Preferably, the mass ratio of the acrylate soft monomer to the acrylate hard monomer is 1:(0.05~0.2). The ratio of soft to hard monomers directly determines the performance balance of the final product, especially in pressure-sensitive adhesives, where this monomer ratio ensures good initial tack while providing sufficient interfacial strength.

[0034] Specifically, the soft acrylate monomer is at least one of ethyl acrylate, butyl acrylate, and isooctyl acrylate; the hard acrylate monomer is at least one of methyl acrylate, methyl methacrylate, ethyl methacrylate, and n-butyl methacrylate.

[0035] Specifically, the chain transfer agent is at least one of n-dodecyl mercaptan, tert-dodecyl mercaptan, and octadecyl mercaptan; the reactive emulsifier is at least one of sodium acrylamide isopropyl sulfonate, sodium monosodium sulfosuccinate of alcohol polyether, and sodium allyl alkyl ether sulfonate.

[0036] Specifically, the anionic emulsifier is at least one of sodium dodecylbenzenesulfonate, sodium dodecyl diphenyl ether disulfonate, and sodium alkyl succinate disulfonate; the initiator is at least one of ammonium persulfate and potassium persulfate.

[0037] Specifically, the pH adjuster is ammonia; the pH buffer is ammonium bicarbonate.

[0038] A specific embodiment of the present invention also provides a method for preparing the carboxyacrylate aqueous dispersion as described above, comprising the following steps:

[0039] S1. Mix acrylate monomers, functional monomers, internal crosslinking monomers, chain transfer agents, 35%~50% deionized water, 55%~80% reactive emulsifiers, 33%~50% initiators, and 40%~60% pH buffers evenly to obtain a pre-emulsion.

[0040] S2. Mix the remaining deionized water, 16%~26% of the reactive emulsifier, the anionic emulsifier, and the remaining pH buffer, stir and heat to 82°C, then add the remaining initiator, stir and mix evenly to obtain the reaction base liquid.

[0041] S3. Under conditions of 80~82℃, the pre-emulsion is added dropwise to the reaction base liquid. 4%~9% of the total amount of pre-emulsion is added dropwise in the first 10 minutes, and 19% of the total amount of pre-emulsion is added dropwise in the next 20 minutes. Then the remaining reactive emulsifier is added. After the reactive emulsifier is added, 4%~9% of the total amount of pre-emulsion is added dropwise in the first 10 minutes, and the remaining pre-emulsion is added dropwise in the next 60~80 minutes. Then the temperature is raised to 88~90℃ and held for 30 minutes to obtain the pre-product.

[0042] S4. After cooling the preproduct to 40℃~50℃, add a pH adjuster, stir evenly, and obtain the carboxyacrylate aqueous dispersion.

[0043] This invention, through step S3, divides the pre-emulsion into two stages of dropwise addition (before and after the addition of the reactive emulsifier in step S3) and controls the dropwise rate, altering the monomer and initiator concentrations, thereby reducing the chain transfer coefficient of the secondary nucleation latex particles, resulting in a higher molecular weight and better cohesion. Specifically, in the first stage when the pre-emulsion is just added to the reaction substrate, the dropwise rate is initially slow and then increases; similarly, in the initial stage of the second stage after the remaining reactive emulsifier has been added, the dropwise rate is also initially slow and then increases. In other words, this invention, through optimization of the carboxyacrylate aqueous dispersion formulation and improvements in the preparation method, enables the prepared carboxyacrylate aqueous dispersion to achieve a solid content of over 69% and low viscosity, and it can also be used to prepare protective films for aluminum profiles.

[0044] In step S3, 19% of the total amount of pre-emulsion is added dropwise over the next 20 minutes, which refers to the 20 minutes between the 10th and 30th minutes after the start of the reaction.

[0045] The carboxyacrylate aqueous dispersion of the present invention can also be prepared by other common preparation methods, and the preparation method of the present invention is only one of them.

[0046] A specific embodiment of the present invention also provides an aluminum profile protective film, including a substrate and an adhesive film disposed on the substrate, wherein the raw materials of the adhesive film include the carboxyacrylate aqueous dispersion and the curing agent as described above.

[0047] Preferably, the raw material of the adhesive film may further include a defoamer, which may be WBA (wax barium sulfate). The main function of the defoamer is to eliminate air bubbles during the coating of the adhesive film raw material onto the substrate. The defoamer may be a raw material for a carboxyacrylate aqueous dispersion, or it may be added after the carboxyacrylate aqueous dispersion has been prepared. The defoamer will not chemically react with other components in the carboxyacrylate aqueous dispersion.

[0048] The following will describe in detail the carboxyacrylate aqueous dispersion of the present invention, its preparation method, and the protective film for aluminum profiles, with reference to specific embodiments and comparative examples.

[0049] Example 1

[0050] Mix 20 parts of deionized water and 0.19 parts of sodium monosodium sulfosuccinate of alcohol polyether at 350 rpm until homogeneous. Slowly add 1.0 part of acrylic acid, 2.0 parts of hydroxyethyl acrylate, 6.5 parts of methyl methacrylate, 18 parts of 2-ethylethyl acrylate (isooctyl acrylate), 72.35 parts of n-butyl acrylate, 0.1 parts of n-dodecyl mercaptan, 0.05 parts of N-hydroxymethylacrylamide, and 0.1 parts of ammonium bicarbonate. Stir for 30 minutes, then add 0.25 parts of ammonium persulfate and mix. Continue stirring for 10 minutes to obtain a pre-emulsion.

[0051] 23 parts of deionized water, 0.09 parts of sodium dodecyl diphenyl ether disulfonate, 0.1 parts of ammonium bicarbonate, and 0.08 parts of sodium monoester of alcohol polyether sulfosuccinate were added to a reaction vessel. The stirring speed was 150 rpm, the temperature was raised to 82°C, 0.5 parts of ammonium persulfate were added, and the mixture was stirred for 10 minutes until the temperature stabilized at 80°C to obtain the reaction base liquid.

[0052] Add pre-emulsion dropwise to the reaction base solution. Add 4% pre-emulsion dropwise over the first 10 minutes, then add 19% pre-emulsion dropwise over the next 20 minutes. Then add 0.07 parts of sodium monosodium sulfosuccinate of alcohol. Then add 4% pre-emulsion dropwise over the next 10 minutes. After the remaining pre-emulsion is added over 80 minutes, heat to 89°C and keep warm for 30 minutes. Add ammonia water to adjust the pH value to 6.0. Stir for 10 minutes, then filter to obtain the carboxyacrylate aqueous dispersion of the present invention.

[0053] Example 2

[0054] Mix 20 parts of deionized water and 0.19 parts of sodium monosodium sulfosuccinate of alcohol polyether at 350 rpm until homogeneous. Slowly add 1.0 part of acrylic acid, 2.0 parts of hydroxyethyl acrylate, 6.5 parts of methyl methacrylate, 18 parts of 2-ethylethyl acrylate (isooctyl acrylate), 72.35 parts of n-butyl acrylate, 0.1 parts of n-dodecyl mercaptan, 0.05 parts of N-hydroxymethylacrylamide, and 0.1 parts of ammonium bicarbonate. Stir for 30 minutes, then add 0.25 parts of ammonium persulfate and mix. Continue stirring for 10 minutes to obtain a pre-emulsion.

[0055] Add 23 parts of deionized water, 0.09 parts of sodium dodecyl diphenyl ether disulfonate, and 0.1 parts of ammonium bicarbonate to a reaction vessel, stir at 150 rpm, heat to 82°C, add 0.5 parts of ammonium persulfate, stir for 10 minutes, and stabilize the temperature at 80°C to obtain the reaction base liquid.

[0056] Add pre-emulsion dropwise to the reaction substrate. Add 6% pre-emulsion dropwise over the first 10 minutes, then add 19% pre-emulsion dropwise over the next 20 minutes. Then add 0.07 parts of sodium monosodium sulfosuccinate of alcohol. Then add 6% pre-emulsion dropwise over the next 10 minutes. After the remaining pre-emulsion is added over 80 minutes, raise the temperature to 88°C and keep it at that temperature for 30 minutes. Add ammonia water to adjust the pH value to 6.0. Add 0.1 parts of WBA, stir for 10 minutes, and then filter to obtain the carboxyacrylate aqueous dispersion of the present invention.

[0057] Example 3

[0058] Mix 20 parts of deionized water and 0.19 parts of sodium monosodium sulfosuccinate of alcohol polyether at 350 rpm until homogeneous. Slowly add 1.0 part of acrylic acid, 1.0 part of hydroxyethyl acrylate, 6.5 parts of methyl methacrylate, 18 parts of 2-ethylethyl acrylate (isooctyl acrylate), 72.35 parts of n-butyl acrylate, 0.2 parts of n-dodecyl mercaptan, 0.05 parts of N-hydroxymethylacrylamide, and 0.1 parts of ammonium bicarbonate. Stir for 30 minutes, then add 0.25 parts of ammonium persulfate and mix. Continue stirring for 10 minutes to obtain a pre-emulsion.

[0059] Add 23 parts of deionized water, 0.09 parts of sodium dodecyl diphenyl ether disulfonate, and 0.1 parts of ammonium bicarbonate to a reaction vessel, stir at 150 rpm, heat to 82°C, add 0.5 parts of ammonium persulfate, stir for 10 minutes, and stabilize the temperature at 80°C to obtain the reaction base liquid.

[0060] Add pre-emulsion dropwise to the reaction substrate. Add 9% pre-emulsion dropwise over the first 10 minutes, then add 19% pre-emulsion dropwise over the next 20 minutes. Then add 0.07 parts of sodium monosodium sulfosuccinate of alcohol. Then add 9% pre-emulsion dropwise over the next 10 minutes. After the remaining pre-emulsion is added dropwise over 60 minutes, raise the temperature to 88°C and keep it at that temperature for 30 minutes. Add ammonia water to adjust the pH value to 6.0. Add 0.1 parts of WBA, stir for 10 minutes, and then filter to obtain the carboxyacrylate aqueous dispersion of the present invention.

[0061] Example 4

[0062] Mix 20 parts of deionized water and 0.19 parts of sodium monosodium sulfosuccinate of alcohol polyether at 350 rpm until homogeneous. Slowly add 1.0 part of acrylic acid, 2.0 parts of hydroxyethyl acrylate, 6.5 parts of methyl methacrylate, 25 parts of 2-ethylethyl acrylate, 65.35 parts of n-butyl acrylate, 0.5 parts of n-dodecyl mercaptan, 0.05 parts of N-hydroxymethylacrylamide, and 0.05 parts of ammonium bicarbonate. Stir for 30 minutes, then add 0.25 parts of ammonium persulfate and mix. Continue stirring for 10 minutes to obtain a pre-emulsion.

[0063] Add 23 parts of deionized water, 0.1 parts of sodium dodecyl diphenyl ether disulfonate, and 0.05 parts of ammonium bicarbonate to a reaction vessel, stir at 150 rpm, heat to 82°C, add 0.5 parts of ammonium persulfate, stir for 10 minutes, and stabilize the temperature at around 82°C to obtain the reaction base liquid.

[0064] Add pre-emulsion dropwise to the reaction base solution. Add 4% pre-emulsion dropwise over the first 10 minutes, then add 19% pre-emulsion dropwise over the next 20 minutes. Then add 0.07 parts of the reactive emulsifier sodium sulfosuccinate monoester. Add the remaining pre-emulsion dropwise over the next 10 minutes. After adding the remaining pre-emulsion dropwise over 80 minutes, heat the solution to 88°C and keep it at that temperature for 30 minutes. Add ammonia water to adjust the pH to 6.0. Add 0.1 parts of WBA, stir for 10 minutes, and then filter to obtain the carboxyacrylate aqueous dispersion of the present invention.

[0065] Example 5

[0066] Mix 20 parts of deionized water and 0.19 parts of sodium monosodium sulfosuccinate of alcohol polyether at 350 rpm until homogeneous. Slowly add 1.0 part of acrylic acid, 2.0 parts of hydroxyethyl acrylate, 6.5 parts of methyl methacrylate, 25 parts of 2-ethylethyl acrylate, 65.35 parts of n-butyl acrylate, 0.1 part of n-dodecyl mercaptan, 0.15 parts of N-hydroxymethylacrylamide, and 0.1 parts of ammonium bicarbonate. Stir for 30 minutes, then add 0.1 parts of ammonium persulfate and mix. Continue stirring for 10 minutes to obtain a pre-emulsion.

[0067] Add 23 parts of deionized water, 0.15 parts of sodium dodecyl diphenyl ether disulfonate, and 0.1 parts of ammonium bicarbonate to a reaction vessel, stir at 150 rpm, heat to 81°C, add 0.3 parts of ammonium persulfate, stir for 10 minutes, and stabilize the temperature at around 81°C to obtain the reaction base liquid.

[0068] Add pre-emulsion dropwise to the reaction substrate. Add 4% pre-emulsion dropwise over the first 10 minutes, then add 19% pre-emulsion dropwise over the next 20 minutes. Then add 0.07 parts of the reactive emulsifier sodium sulfosuccinate monoester. Next, add 6% pre-emulsion dropwise over the next 10 minutes. After the remaining pre-emulsion is added over 80 minutes, raise the temperature to 89°C and keep it at that temperature for 30 minutes. Adjust the pH value to 6.0, add 0.1 parts of WBA, stir for 10 minutes, and then filter to obtain the carboxyacrylate aqueous dispersion of the present invention.

[0069] Example 6

[0070] Mix 20 parts of deionized water and 0.19 parts of sodium monosodium sulfosuccinate of alcohol polyether at 350 rpm until homogeneous. Slowly add 1.0 part of acrylic acid, 2.0 parts of hydroxyethyl acrylate, 6.5 parts of methyl methacrylate, 25 parts of 2-ethylethyl acrylate, 65.35 parts of n-butyl acrylate, 0.1 parts of n-dodecyl mercaptan, and 1.5 parts of N-hydroxymethylacrylamide. After stirring for 30 minutes, add 3 parts of ammonium persulfate and mix. Continue stirring for 10 minutes to obtain a pre-emulsion.

[0071] Add 30 parts of deionized water, 0.09 parts of sodium dodecyl diphenyl ether disulfonate, and 0.12 parts of ammonium bicarbonate to a reaction vessel, stir at 150 rpm, heat to 80°C, add 0.5 parts of ammonium persulfate, stir for 10 minutes, and stabilize the temperature at around 80°C to obtain the reaction base liquid.

[0072] Add pre-emulsion dropwise to the reaction substrate. Add 4% pre-emulsion dropwise over the first 10 minutes, then add 19% pre-emulsion dropwise over the next 20 minutes. Then add 0.07 parts of the reactive emulsifier sodium sulfosuccinate monoester. Add the remaining pre-emulsion dropwise over the next 10 minutes. After adding the remaining pre-emulsion dropwise over 80 minutes, heat to 90°C and keep warm for 30 minutes. Add ammonia water to adjust the pH to 6.0. Add 0.1 parts of WBA, stir for 10 minutes, and then filter to obtain the carboxyacrylate aqueous dispersion of the present invention.

[0073] Comparative Example 1

[0074] Mix 20 parts of deionized water and 0.19 parts of sodium monosodium sulfosuccinate of alcohol polyether at 350 rpm until homogeneous. Slowly add 1.0 part of acrylic acid, 2.0 parts of hydroxyethyl acrylate, 6.5 parts of methyl methacrylate, 18 parts of 2-ethylethyl acrylate (isooctyl acrylate), 72.35 parts of n-butyl acrylate, 0.1 parts of n-dodecyl mercaptan, 0.05 parts of N-hydroxymethylacrylamide, and 0.1 parts of ammonium bicarbonate. Stir for 30 minutes, then add 0.25 parts of ammonium persulfate and mix. Continue stirring for 10 minutes to obtain a pre-emulsion.

[0075] 23 parts of deionized water, 0.09 parts of sodium dodecyl diphenyl ether disulfonate, 0.1 parts of ammonium bicarbonate, and 0.08 parts of sodium monoester of alcohol polyether sulfosuccinate were added to a reaction vessel. The stirring speed was 150 rpm, the temperature was raised to 82°C, 0.5 parts of ammonium persulfate were added, and the mixture was stirred for 10 minutes until the temperature stabilized at 80°C to obtain the reaction base liquid.

[0076] Add pre-emulsion dropwise to the reaction base solution. Add 4% pre-emulsion dropwise in the first 10 minutes, and 19% pre-emulsion dropwise from 10 to 30 minutes. Add 0.07 parts of reactive emulsifier sodium sulfosuccinate monoester at 30 minutes of reaction. After the remaining pre-emulsion is added dropwise over 90 minutes, raise the temperature to 89°C and keep it at that temperature for 30 minutes. Add ammonia water to adjust the pH value to 6.0. After stirring for ten minutes, filter the material to obtain carboxyacrylate aqueous dispersion.

[0077] Comparative Example 2

[0078] Mix 20 parts of deionized water and 0.19 parts of sodium monosodium sulfosuccinate of alcohol polyether at 350 rpm until homogeneous. Slowly add 1.0 part of acrylic acid, 2.0 parts of hydroxyethyl acrylate, 6.5 parts of methyl methacrylate, 18 parts of 2-ethylethyl acrylate (isooctyl acrylate), 72.35 parts of n-butyl acrylate, 0.1 parts of n-dodecyl mercaptan, 0.05 parts of N-hydroxymethylacrylamide, and 0.1 parts of ammonium bicarbonate. Stir for 30 minutes, then add 0.25 parts of ammonium persulfate and mix. Continue stirring for 10 minutes to obtain a pre-emulsion.

[0079] 23 parts of deionized water, 0.16 parts of sodium dodecyl diphenyl ether disulfonate, 0.1 parts of ammonium bicarbonate, and 0.15 parts of sodium monoester of alcohol polyether sulfosuccinate were added to a reaction vessel. The stirring speed was 150 rpm, the temperature was raised to 82°C, 0.5 parts of ammonium persulfate were added, and the mixture was stirred for 10 minutes until the temperature stabilized at 80°C to obtain the reaction base liquid.

[0080] Add pre-emulsion dropwise to the reaction base liquid. Add 4% of the pre-emulsion dropwise in the first 10 minutes. After the remaining pre-emulsion dropwise is added over 110 minutes, heat the mixture to 89°C and keep it at that temperature for 30 minutes. Add ammonia water to adjust the pH value to 6.0. Stir for 10 minutes and then filter the mixture to obtain a carboxyacrylate aqueous dispersion.

[0081] Comparative Example 3

[0082] Mix 20 parts of deionized water and 0.19 parts of sodium monosodium sulfosuccinate of alcohol polyether at 350 rpm until homogeneous. Slowly add 1.0 part of acrylic acid, 2.0 parts of hydroxyethyl acrylate, 6.5 parts of methyl methacrylate, 18 parts of 2-ethylethyl acrylate (isooctyl acrylate), 72.35 parts of n-butyl acrylate, 0.1 parts of n-dodecyl mercaptan, 0.05 parts of N-hydroxymethylacrylamide, and 0.1 parts of ammonium bicarbonate. Stir for 30 minutes, then add 0.25 parts of ammonium persulfate and mix. Continue stirring for 10 minutes to obtain a pre-emulsion.

[0083] 23 parts of deionized water, 0.09 parts of sodium dodecyl diphenyl ether disulfonate, 0.1 parts of ammonium bicarbonate, and 0.08 parts of sodium monoester of alcohol polyether sulfosuccinate were added to a reaction vessel. The stirring speed was 150 rpm, the temperature was raised to 82°C, 0.5 parts of ammonium persulfate were added, and the mixture was stirred for 10 minutes until the temperature stabilized at 80°C to obtain the reaction base liquid.

[0084] Add pre-emulsion dropwise to the reaction base liquid. Add 23% of the pre-emulsion dropwise in the first 30 minutes. Add 0.07 parts of the reactive emulsifier sodium sulfosuccinate monoester at 30 minutes of reaction. Adjust the dropping rate and add 4% of the pre-emulsion dropwise in 10 minutes. After the remaining pre-emulsion is added in 80 minutes, raise the temperature to 89°C and keep it at that temperature for 30 minutes. Add ammonia water to adjust the pH value to 6.0. After stirring for ten minutes, filter the material to obtain carboxyacrylate aqueous dispersion.

[0085] The following performance tests were performed on the carboxyacrylate aqueous dispersions in Examples 1-6 and Comparative Examples 1-3:

[0086] (1) Emulsion solid content: According to GB / T 11175-2002 "Test Methods for Synthetic Resin Emulsions"

[0087] (2) Emulsion viscosity: according to GB / T 10247-2008 "Viscosity Measurement Methods"

[0088] (3) Particle size distribution of emulsion (tested only for Example 1): 90 Plus Pals particle size analyzer, the emulsion was diluted with deionized water to the measurement range, and the average value was taken after six tests. The test temperature in the 90 Plus Pals particle size analyzer was 25°C, the dispersion medium was water with a viscosity of about 0.89 cp, the refractive index of the dispersion medium was 1.33, the detection angle was 90°, the wavelength was 660 nm, the baseline was automatically controlled (slope analysis), the number of runs was 6, the time of each run was 1 min, the total time used was 6 min, the average count rate was 95.0 kcps, the real refractive index was 1.59, and the imaginary refractive index was 0.

[0089] The table shown in Table 1 and the table shown in Table 2 are obtained. Figure 1 The data chart shown.

[0090] Table 1

[0091]

[0092] As shown in Table 1, the basic physical property test results of Examples 1-2-3-4-5-6 and Comparative Example 1 all achieved a viscosity of less than 550 mPa at a solid content of 69%, meeting the requirement of high solid content and low viscosity. In Comparative Example 2, after removing the added emulsifier, the viscosity increased significantly because the particle size distribution narrowed, leading to denser latex particle packing, reduced free water, increased interaction forces between latex particles, and a large steric repulsion force. Comparative Example 3 changed the initial dropping rate, resulting in a smaller initial latex particle size, an increased total number of latex particles in the system, reduced free water, and enhanced interaction forces between latex particles. Even with a bimodal particle size distribution, the system viscosity remained high.

[0093] from Figure 1 It can be seen that its effective diameter is 486.3 nm, its polydispersity is 0.074, its baseline index is 7.9, and its measurement efficiency is 6 min, meaning that the total time taken is only 6 minutes.

[0094] The carboxyacrylate aqueous dispersions from Examples 1-6 and Comparative Examples 1-3 were mixed uniformly with a curing agent (aziridine). The amount of aziridine added was 0.05% of the mass of the carboxyacrylate aqueous dispersion. The resulting mixture was applied by hand to a 110 μm polyethylene substrate with an application rate of 40 g / m². 2 Then, after curing (curing at 90℃ for 5 minutes), the following performance tests were performed.

[0095] (1) Initial tack test: according to GB / T 4852-2002 "Test method for initial tack of pressure sensitive adhesive tape (rolling ball method)";

[0096] (2) Holding power test: according to GB / T 4851-2012 "Test method for holding power of adhesive tape";

[0097] (3) Peel strength test: according to GB / T 2792 "Test method for peel strength of adhesive tape".

[0098] The table shown in Table 2 is obtained.

[0099] Table 2

[0100]

[0101] The test results in Table 2 show that Examples 1 to 6 all exhibit high initial tack (>30#), excellent holding power (>55h), moderate peel strength, and low peel strength growth. Furthermore, after soaking in water at 80°C for 3 hours on an aluminum profile, no adhesive residue remains after peeling. Comparative Example 1, while possessing the same basic physical properties and three-force properties as Example 1, exhibits higher peel strength growth and leaves adhesive residue after soaking in water at 80°C on a frosted aluminum profile. Comparative Example 2, although leaving no adhesive residue after soaking in water at 80°C on a frosted aluminum profile, suffers from adhesion problems after soaking and has high viscosity, falling outside the high solids content, low viscosity range. Comparative Example 3, while performing well after soaking in water at 80°C on a frosted aluminum profile, also has high viscosity, falling outside the high solids content, low viscosity range. Therefore, the carboxyacrylate aqueous dispersions of Comparative Examples 1 to 3 are not suitable for use in the field of protective films for aluminum profiles. Thus, the carboxyacrylate aqueous dispersion of the present invention possesses good initial tack and reliable high-temperature and high-humidity resistance, making it applicable to the field of protective films for aluminum profiles.

[0102] It will be apparent to those skilled in the art that this disclosure is not limited to the details of the exemplary embodiments described above, and that this disclosure can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of this disclosure is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this disclosure. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0103] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A protective film for aluminum profiles, characterized in that, It includes a substrate and an adhesive film disposed on the substrate, wherein the raw materials of the adhesive film include a carboxyacrylate aqueous dispersion and a curing agent; The raw materials for the carboxyacrylate aqueous dispersion include a pH adjuster for adjusting the pH value during the preparation process. The carboxyacrylate aqueous dispersion, by mass parts, further includes the following raw material components: 85-98 parts acrylate monomer, 2-3 parts functional monomer, 0.05-1.5 parts internal crosslinking monomer, 0.1-0.5 parts chain transfer agent, 0.33-1 part reactive emulsifier, 0.09-0.15 parts anionic emulsifier, 0.4-0.8 parts initiator, 0.1-0.2 parts pH buffer, and 43-50 parts deionized water. The functional monomer is at least one of acrylic acid, methacrylic acid and hydroxyethyl acrylate; the internal crosslinking monomer is at least one of N-hydroxymethylacrylamide and butoxyacrylamide. The acrylate monomers include soft acrylate monomers and hard acrylate monomers; the soft acrylate monomers are at least one of ethyl acrylate, butyl acrylate, and isooctyl acrylate; the hard acrylate monomers are at least one of methyl acrylate, methyl methacrylate, and n-butyl methacrylate. The method for preparing the carboxyacrylate aqueous dispersion includes the following steps: The acrylate monomer, functional monomer, internal crosslinking monomer, chain transfer agent, 35%–50% deionized water, 55%–80% reactive emulsifier, 33%–50% initiator, and 40%–60% pH buffer are stirred and mixed evenly to obtain a pre-emulsion. The remaining deionized water, 16%–26% of reactive emulsifier, anionic emulsifier, and remaining pH buffer are mixed and stirred, and then heated to 82°C. The remaining initiator is added, and the mixture is stirred until homogeneous to obtain the reaction base solution. Under conditions of 80-82℃, the pre-emulsion is added dropwise to the reaction base liquid. 4%-9% of the total amount of pre-emulsion is added dropwise in the first 10 minutes, followed by 19%-29% over the next 20 minutes. Then, the remaining reactive emulsifier is added. After the reactive emulsifier is added, 4%-9% of the total amount of pre-emulsion is added dropwise over the first 10 minutes, followed by the remaining pre-emulsion over 60-80 minutes. The temperature is then raised to 88-90℃ and held for 30 minutes to obtain the pre-product. After cooling the preproduct to 40℃~50℃, a pH adjuster is added, and the mixture is stirred evenly to obtain the carboxyacrylate aqueous dispersion.

2. The aluminum profile protective film according to claim 1, characterized in that, The mass ratio of the acrylate soft monomer to the acrylate hard monomer is 1:(0.05~0.2).

3. The aluminum profile protective film according to claim 1, characterized in that, The chain transfer agent is at least one of n-dodecyl mercaptan, tert-dodecyl mercaptan, and octadecyl mercaptan.

4. The aluminum profile protective film according to claim 1, characterized in that, The reactive emulsifier is at least one of sodium acrylamide isopropyl sulfonate, sodium monoester of alcohol polyether sulfosuccinate, and sodium allyl alkyl ether sulfonate.

5. The aluminum profile protective film according to claim 1, characterized in that, The anionic emulsifier is at least one of sodium dodecylbenzenesulfonate, sodium dodecyl diphenyl ether disulfonate, and sodium alkyl succinate disulfonate. The initiator is at least one of ammonium persulfate and potassium persulfate.

6. The aluminum profile protective film according to claim 1, characterized in that, The pH adjuster is ammonia; the pH buffer is ammonium bicarbonate.

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