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CN-121991395-A - Acrylic air foam with high buffering property and water resistance and preparation method thereof

CN121991395ACN 121991395 ACN121991395 ACN 121991395ACN-121991395-A

Abstract

The invention relates to the field of high polymer materials, in particular to acrylic air foam with high buffering property and water resistance and a preparation method thereof, wherein the acrylic air foam is prepared from the following raw materials, by weight, 100 parts of acrylic ester copolymer prepolymer, 0.5-2 parts of cross-linking agent, 0.5-3 parts of foam cell structure stabilizer, 2-8 parts of chemical foaming agent and 0.1-1 part of photoinitiator, wherein the acrylic ester copolymer prepolymer is slurry with certain viscosity formed by prepolymerizing a plurality of acrylic ester monomers under the action of the photoinitiator, the 24-hour water absorption rate of the foam can be lower than 0.5%, the static water contact angle is larger than 110 DEG, and the foam is far superior to the traditional acrylic foam, and the long-term water resistance reliability under severe environment is ensured.

Inventors

  • WU DAN
  • LUO JUNLONG
  • Luo Jiuchuan

Assignees

  • 浙江欧克实业有限公司

Dates

Publication Date
20260508
Application Date
20260303

Claims (9)

  1. 1. The acrylic air foam with high buffering performance and waterproof performance is characterized by comprising, by weight, 100 parts of acrylic ester copolymer prepolymer, 0.5-2 parts of cross-linking agent, 0.5-3 parts of cell structure stabilizer, 2-8 parts of chemical foaming agent and 0.1-1 part of photoinitiator, wherein the acrylic ester copolymer prepolymer is slurry with certain viscosity formed by prepolymerizing a plurality of acrylic ester monomers under the action of the photoinitiator.
  2. 2. The acrylic air foam according to claim 1, wherein the acrylic copolymer prepolymer is composed of the following raw materials in parts by weight, soft monomers in 60-80 parts; 10-20 parts of hard monomer, 1-5 parts of adhesive force functional monomer and 5-15 parts of hydrophobic functional monomer.
  3. 3. The acrylic air foam of claim 2 wherein the soft monomer is one or more of butyl acrylate, 2-ethylhexyl acrylate, and isooctyl acrylate.
  4. 4. The acrylic air foam of claim 2 wherein the hard monomer is one or more of methyl methacrylate, isobornyl acrylate, and t-butyl acrylate.
  5. 5. The acrylic air foam of claim 2 wherein the functional monomer is one or more of acrylic acid and 2-hydroxyethyl acrylate.
  6. 6. The acrylic air foam of claim 2 wherein the hydrophobic functional monomer is one or more of dodecafluoroheptyl methacrylate, 2-trifluoroethyl-alpha-fluoroacrylate, and hexafluorobutyl methacrylate.
  7. 7. The acrylic air foam of claim 1 wherein the cross-linking agent is one or more of (2, 3-glycidoxy) propyl trimethoxysilane, gamma-aminopropyl triethoxysilane, or methacryloxypropyl trimethoxysilane.
  8. 8. The acrylic air foam of claim 1 wherein the photoinitiator is one or more of 2-hydroxy-2-methylpropionacetone and diphenyl (2, 4, 6-trimethylbenzoyl) phosphine oxide.
  9. 9. A method for preparing acrylic air foam according to any one of claims 1 to 8, which is characterized by comprising the following steps, Step one, preparing prepolymer slurry, namely uniformly mixing a soft monomer, a hard monomer, an adhesive force functional monomer, a hydrophobic functional monomer and a photoinitiator in a light-proof and temperature-controlled reaction kettle, introducing nitrogen for protection, and irradiating with low-intensity ultraviolet light under stirring to perform partial polymerization until the system viscosity reaches 1000-5000cps to form uniform and transparent prepolymer slurry; Step two, mixing and defoaming, namely cooling the prepared prepolymer slurry to room temperature, sequentially adding a cross-linking agent, a foam cell structure stabilizer, a foaming agent and an activating agent, stirring at a low speed by using a planetary stirrer under a light-shielding condition until all components are completely and uniformly dispersed, and then carrying out vacuum defoaming treatment on the mixture to thoroughly remove air wrapped in the mixture; And thirdly, coating and UV curing, namely accurately coating the defoamed uniform slurry on a single-sided siliconized PET release film by a doctor blade coater, wherein the thickness of the coating is controlled to be 500-1500 mu m. Subsequently, the coated material belt is provided with A UV curing areA, A plurality of medium-pressure mercury lamps are arranged in the areA, and the coating is subjected to the radiation energy of the UV-A wave band of 1000-3000 mJ/cm 2 by controlling the speed of the conveyor belt and the power of the lamp tube; Continuously feeding the precursor film subjected to UV curing into a tunnel oven with a multi-temperature zone, setting the temperature gradient of the oven, enabling the temperature of the film to be steadily increased to 140-160 ℃ and kept for a period of time, and at the temperature, heating and decomposing the activated foaming agent to release a large amount of nitrogen, and expanding the gas in a polymer matrix softened by heat to form a uniform closed cell structure; and fifthly, cooling and obtaining a finished product, namely cooling the foam cotton belt subjected to foam molding to room temperature through a cooling area, covering a second release film according to requirements, and finally rolling to obtain the finished product.

Description

Acrylic air foam with high buffering property and water resistance and preparation method thereof Technical Field The invention relates to the field of high polymer materials, in particular to acrylic air foam with high buffering property and water resistance and a preparation method thereof. Background Acrylic foam, i.e., acrylic foam, is widely used as a high-performance viscoelastic material in a variety of critical fields such as consumer electronics, automobile manufacturing, construction, home appliances, and new energy sources due to its excellent adhesion, weather resistance, durability, and shock absorbing and cushioning properties. In electronic equipment such as smart phones and tablet computers, an acrylic foam tape is commonly used for bonding, sealing and buffering components such as a screen, a rear cover and a battery, and plays key roles of dust prevention, water prevention and impact resistance. In the automobile industry, the fixing device is used for fixing the automobile body decorative strips, the marks and the sealing strips, and effectively absorbs vibration and reduces noise. With the development of technology, particularly the evolution of electronic devices toward lighter, thinner, more integrated and more reliable, the performance requirements for acrylic foam materials are also becoming increasingly stringent, and there is a strong market demand for a single material solution that can provide both high level of waterproof protection and excellent impact buffering capability. At present, in order to realize the buffering and waterproof functions of acrylic foam, the following technical schemes mainly exist: Scheme one, traditional high density closed cell acrylic foam This approach is the dominant technology on the market, with representative products such as VH series tape from 3M company and ACXplus series tape from TESA company. The product physically blocks the invasion of moisture and dust by forming a closed and non-connected cell structure, thereby realizing the sealing and waterproof functions. The waterproof performance of the material mainly depends on the integrity of cell walls and the overall compactness of the material. To ensure reliable water-repellent effect, such foams are generally of high density and relatively hard texture. Scheme II, composite structure of open-pore foam and waterproof coating/film In pursuit of the excellent cushioning properties, some proposals use soft, highly compressible open-celled foam (e.g., polyurethane foam) as a core material because of its open-celled structure which provides excellent compression rebound characteristics. However, open-cell foam itself does not have a waterproof capability, and water and moisture can freely penetrate. Therefore, it is necessary to compound a dense waterproof film (e.g., PET, TPU film) or a waterproof coating (e.g., acrylic or silicone coating) on the surface thereof to provide a waterproof function. This approach achieves functional complementation by a combination of layers of materials. Scheme III foam prepared by physical foaming agent (such as hollow microsphere) According to the scheme, hollow glass microspheres or expandable polymer microspheres are added into an acrylic resin matrix to serve as a pore-forming agent. During processing, the microspheres are dispersed in the matrix to form a porous structure, which has the effects of reducing density and providing a certain buffer effect. The method has relatively simple process and controllable cost. The prior art schemes have obvious limitations in practical application, and are specifically as follows: the inherent contradiction and compromise in performance is that for scheme one, its core drawback is the negative correlation between cushioning and water repellency. In order to obtain IPX7 and even IPX8 grade water resistance, the foam must have extremely low air permeability and extremely high closed cell content, which generally requires an increase in foam density and hardness, resulting in a decrease in compression resilience and poor cushioning. Conversely, if the cushioning property is to be improved to reduce the density, the pore wall of the foam becomes thinner, the structural strength is reduced, and the foam is easy to crack or creep under long-term compression or vibration stress, so that the waterproof sealing is invalid. This compromise in design limits its application in demanding scenarios where both high buffering and high water resistance are required. The problems of structural complexity, high cost and reliability are that for the scheme II, the multilayer composite structure of the scheme II obviously increases production procedures such as film coating, hot-pressing lamination and the like, so that the manufacturing cost is high and the production efficiency is low. More seriously, it introduces a structural weakness of "interface". In the long-term use process of the interface between the foam core material and the