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CN-121975300-A - Sound insulation earplug with improved slow rebound performance and preparation method thereof

CN121975300ACN 121975300 ACN121975300 ACN 121975300ACN-121975300-A

Abstract

The invention discloses a sound insulation earplug with improved slow rebound performance and a preparation method thereof, and belongs to the technical field of high polymer protective materials. The earplug raw materials comprise isocyanate prepolymer, polyol, a composite modifier, a foaming agent, a catalyst and the like, wherein the composite modifier is prepared by mixing modified nano silicon dioxide, polybutene and acetyl tributyl citrate according to a specific proportion, and the preparation method comprises the steps of composite modifier preparation, premixing, foaming reaction and post-treatment. The invention solves the problems of unstable slow rebound performance, sound insulation, difficult compromise of slow rebound, poor durability and the like of the traditional earplug by the synergistic effect of the composite modifier and the raw material proportion. The earplug has stable slow rebound performance under different temperature environments, rebound time of 8-75s, comprehensive sound insulation volume of 35-42dB, rebound deformation rate less than or equal to 3% for 500 times, good compatibility, no precipitation, long service life, and suitability for mass production, and is suitable for various noise reduction scenes.

Inventors

  • LIN TAIQIN

Assignees

  • 广东金海纳实业有限公司

Dates

Publication Date
20260505
Application Date
20260306

Claims (9)

  1. 1. The sound insulation earplug with the improved slow rebound performance is characterized by comprising, by weight, 40-60 parts of isocyanate prepolymer, 20-30 parts of polyol, 5-12 parts of composite modifier, 1-5 parts of foaming agent, 0.5-2 parts of catalyst, 0.3-1 part of anti-aging agent, 1-3 parts of flame retardant and 0.1-0.5 part of defoaming agent; The composite modifier is formed by mixing modified nano silicon dioxide, polybutene and acetyl tributyl citrate according to the weight ratio of 2-4:1-3:1-2; The modified nano silicon dioxide is nano silicon dioxide modified by an aminosilane coupling agent, and the particle size is 50-100nm.
  2. 2. The sound-insulating earplug with improved slow rebound property as claimed in claim 1, wherein said isocyanate prepolymer is prepared by reacting toluene diisocyanate with polyether polyol, wherein the isocyanate group content is 8-12%.
  3. 3. The sound-insulating earplug with improved slow rebound property according to claim 1, wherein the polyol is a mixture of polyether polyol and polyester polyol in a weight ratio of 3-5:1, wherein the hydroxyl value of the polyether polyol is 200-300mgKOH/g, and the hydroxyl value of the polyester polyol is 150-250mgKOH/g.
  4. 4. The soundproofing earplug with improved slow rebound property according to claim 1, wherein the raw materials comprise 48-55 parts by weight of isocyanate prepolymer, 24-28 parts by weight of polyol, 7-10 parts by weight of composite modifier, 2-4 parts by weight of foaming agent, 0.8-1.5 parts by weight of catalyst, 0.5-0.8 parts by weight of anti-aging agent, 1.5-2.5 parts by weight of flame retardant and 0.2-0.4 parts by weight of defoaming agent.
  5. 5. The soundproofing earplug with improved slow rebound property according to any one of claims 1 to 4, wherein the composite modifier is formed by mixing modified nano silica, polybutene and acetyl tributyl citrate according to a weight ratio of 3:2:1.5, wherein the particle size of the modified nano silica is 60-80nm, and the modification amount of the silane coupling agent KH-550 is 5-8% of the mass of the nano silica.
  6. 6. The sound-insulating earplug with improved slow rebound resilience of any one of claims 1 to 4 wherein the molar ratio of toluene diisocyanate to polyether polyol in the isocyanate prepolymer is 1.8 to 2.2:1 and the polyether polyol is a polyoxypropylene polyol having a molecular weight of 1000 to 2000 Da.
  7. 7. The sound insulating earplug of any one of claims 1-4 wherein the weight ratio of polyether polyol to polyester polyol is 4:1, the polyether polyol is a polyoxyethylene-oxypropylene block polyol, and the polyester polyol is a polyethylene adipate polyol.
  8. 8. The sound insulating earplug with improved slow rebound performance of any one of claims 1-4 wherein the foaming agent is deionized water and n-pentane mixed in a weight ratio of 1-2:1, the catalyst is dibutyl tin dilaurate and triethanolamine mixed in a weight ratio of 1:1-2, the anti-aging agent is hindered phenol anti-aging agent 1010, the flame retardant is aluminum hydroxide, and the defoaming agent is an organosilicon defoaming agent.
  9. 9. A method of making a sound-insulating earplug of any one of claims 1-8 having improved slow rebound properties, comprising the steps of: s1, preparing a composite modifier, namely adding modified nano silicon dioxide, polybutene and acetyl tributyl citrate into a high-speed mixer, and mixing for 20-30min at the rotation speed of 800-1200r/min and the temperature of 40-50 ℃ to obtain the composite modifier for later use; S2, premixing, namely adding the polyol, the composite modifier, the anti-aging agent, the flame retardant and the defoaming agent into a mixing kettle, and stirring for 15-25min at the rotation speed of 500-800r/min and the temperature of 30-40 ℃ to obtain a premix; s3, foaming reaction, namely cooling the premix to 20-25 ℃, adding a foaming agent and a catalyst, stirring for 5-10S until the mixture is uniformly mixed, rapidly pouring the mixture into a mold, and foaming and curing the mixture for 15-20min under the environment of 25-30 ℃ and humidity of 40-60%, thus obtaining a foam blank; And S4, post-treatment, namely taking the foam blank out of the die, putting the foam blank into a constant temperature oven, curing for 2-3 hours at 60-70 ℃, cutting the foam blank into earplug shapes with preset sizes, and polishing the foam blank to be smooth.

Description

Sound insulation earplug with improved slow rebound performance and preparation method thereof Technical Field The invention relates to the technical field of high polymer protective materials, in particular to a sound insulation earplug with improved slow rebound performance and a preparation method thereof. Background The sound insulation earplug is taken as a common noise reduction product, is widely applied to scenes such as sleeping, industrial operation, transportation and the like, and has the core performance requirements of excellent sound insulation effect and good slow rebound performance. The comfort level and the fitting degree of the earplug can be directly determined by the slow rebound performance, namely, the high-quality slow rebound earplug can be slowly restored after being pressed, different auditory canal sizes are adapted, the earplug is closely fitted with the auditory canal wall to block noise transmission, meanwhile, auditory canal pressing sense caused by too fast rebound is avoided, and discomfort caused by long-term wearing is reduced. At present, the sound insulation earplug in the market is prepared by taking polyurethane foam as a main raw material through a foaming process. In the prior art, in order to improve the slow rebound performance, the method of adjusting the proportion of isocyanate and polyol in polyurethane raw materials and adding a single plasticizer or cross-linking agent is generally adopted for improvement, but a plurality of technical problems still exist, namely, 1. The slow rebound performance is unstable, the rebound speed is obviously accelerated in a low-temperature environment (0-10 ℃), the rebound hysteresis is easy to occur and the problem that the rebound is not completely restored is poor in suitability in a high-temperature environment (35-45 ℃), 2. The sound insulation performance and the slow rebound performance are difficult to be compatible, most schemes can lead to the internal pore structure of the earplug to be enlarged and the pore distribution to be uneven when the slow rebound is optimized, further the blocking effect of low-frequency noise (500-2000 Hz) is reduced, 3. The durability is poor, after the slow rebound is compressed for many times, the earplug is easy to deform, age and crack, the service life is short, 4. The modifier added in part of schemes is poor in compatibility with the polyurethane matrix, the problems of precipitation and layering are easy to occur, and the integral performance and the service safety of the earplug are influenced. For example, patent publication No. CN116874737a proposes a low-temperature-sensitive noise-reducing earplug composite material, which improves the problem of low-temperature hardening, but does not optimize the precise regulation and control of rebound time and the cooperative improvement of sound insulation performance, the rebound time is still limited in a conventional range, and the mechanical performance is obviously attenuated after long-term use. In addition, the spherical filler is adopted in the prior art to adjust rebound performance, but effective molecular chain blocking cannot be formed, so that the rebound speed adjusting and controlling effect is limited, and meanwhile, the soft fit degree of the earplug is damaged. Therefore, developing a sound-insulating earplug with stable slow rebound resilience, excellent sound-insulating effect, good durability and different environmental suitability becomes a technical problem to be solved in the current field. Disclosure of Invention Aiming at the technical problems that in the prior art, the sound insulation earplug is unstable in slow rebound performance, sound insulation and slow rebound are difficult to take account of, durability is poor, and the like, the invention provides the sound insulation earplug with improved slow rebound performance and a preparation method thereof. The invention provides a sound insulation earplug with improved slow rebound performance, which comprises, by weight, 40-60 parts of isocyanate prepolymer, 20-30 parts of polyol, 5-12 parts of composite modifier, 1-5 parts of foaming agent, 0.5-2 parts of catalyst, 0.3-1 part of anti-aging agent, 1-3 parts of flame retardant and 0.1-0.5 part of defoaming agent; The composite modifier is formed by mixing modified nano silicon dioxide, polybutene and acetyl tributyl citrate according to the weight ratio of 2-4:1-3:1-2, wherein the modified nano silicon dioxide is nano silicon dioxide modified by an aminosilane coupling agent, and the particle size is 50-100nm; the aminosilane coupling agent is KH-550; the isocyanate prepolymer is prepared by reacting toluene diisocyanate with polyether polyol, wherein the content of isocyanate groups (NCO%) is 8-12%; the polyol is formed by mixing polyether polyol and polyester polyol according to a weight ratio of 3-5:1, wherein the hydroxyl value of the polyether polyol is 200-300mgKOH/g, and the hydroxyl value of the poly