Preparation method of environment-friendly hot melt adhesive for encircling filter element of household air purifier

Abstract

The invention relates to a preparation method of an environment-friendly hot melt adhesive for encircling a filter element of a household air purifier. The preparation method comprises the following steps: (1) adding Fischer-Tropsch wax, polyethylene wax, a plant-based plasticizer and an antioxidant into a reaction kettle, heating to 140-160 DEG C, stirring at the rotating speed of 20-30 revolutions per minute until all the materials are molten, and keeping the temperature constant; (2) adding metallocene catalyzed polyolefin and random polyolefin, dissolving the metallocene catalyzed polyolefin and the random polyolefin one by one, stirring at the rotating speed of 20-50 revolutions per minute until the metallocene catalyzed polyolefin and the random polyolefin are completely molten, and keeping the temperature at 160-180 DEG C And (3) adding the hydrogenated tackifying resin, the pure monomer resin and the nanoscale silica gel particles, reducing the stirring rotating speed to 10-30 revolutions per minute, and introducing the mixture into a screw extruder for extrusion granulation after the mixture is fully and uniformly stirred, thereby obtaining the environment-friendly hot melt adhesive finished product. The finished product disclosed by the invention has the characteristics of high sealing property, temperature resistance, aging resistance and low VOC (Volatile Organic Compound) emission.

Description

Technical Field

[0001] The invention relates to a method for preparing an environmentally friendly hot melt adhesive, in particular to a method for preparing an environmentally friendly hot melt adhesive for a household air purifier filter element, which is specially used in the household air purifier filter element. Background Art

[0002] As people's attention to indoor air quality continues to increase, the market for household air purifiers continues to expand. According to industry data, the global household air purifier filter market will exceed 35 billion yuan in 2024, with an annual growth rate of 15%, of which China accounts for more than 70% of the total production capacity. Among existing air filter products, the filter element circle (that is, the filter element is positioned and sealed during the folding process) is mostly fixed with traditional EVA hot melt adhesive or mechanical fixation. There are problems such as insufficient sealing, easy aging, and reduced filtration efficiency. More efficient low-VOC hot melt adhesive is urgently needed. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art and to provide a method for preparing an environmentally friendly hot melt adhesive for household air purifier filter element with high sealing, temperature resistance, aging resistance and low VOC emission characteristics.

[0004] The technical solution adopted by the present invention to solve the above problem is: a method for preparing the environmentally friendly hot melt adhesive surrounding the filter element of the household air purifier, which is characterized by the following steps:

[0005] (1) Adding Fischer-Tropsch wax, polyethylene wax, plant-based plasticizer and antioxidant into a reactor, wherein the Fischer-Tropsch wax is 1 to 5 parts, the polyethylene wax is 5 to 13 parts, the plant-based plasticizer is 10 to 30 parts, and the antioxidant is 0.3 to 1 part; heating to 140° C. to 160° C. and stirring at a stirring speed of 20 to 30 revolutions per minute until all melted and the temperature is constant; using Fischer-Tropsch wax and polyethylene wax as viscosity and open time regulators, the fluidity and dispersibility are good, and the high temperature resistance is improved; the plant-based plasticizer can reduce VOC emissions; a small amount of high-quality antioxidant can slow down the aging of the material during the heating process and increase the life of the finished product in normal use;

[0006] (2) Adding metallocene-catalyzed polyolefin and random polyolefin, wherein the metallocene-catalyzed polyolefin is 35-45 parts and the random polyolefin is 10-15 parts; dissolving them one by one, stirring at a speed of 20-50 revolutions per minute, until all are melted and the temperature is kept constant at 160°C to 180°C; the metallocene-catalyzed polyolefin has good flexibility and low temperature resistance, and the random polyolefin has good surface wettability and ductility, and has good compatibility with Fischer-Tropsch wax, polyethylene wax, and plant-based plasticizer;

[0007] (3) Add hydrogenated tackifying resin, pure monomer resin and nano-sized silica gel particles, wherein the hydrogenated tackifying resin is 40 to 50 parts, the pure monomer resin is 10 to 15 parts, and the nano-sized silica gel particles are 0.5 to 5 parts; reduce the stirring speed to 10 to 30 revolutions per minute, wait for it to be fully stirred, introduce it into a screw extruder for extrusion and granulation, and obtain an environmentally friendly hot melt adhesive product; hydrogenated tackifying resin and pure monomer resin are used as tackifiers to effectively improve the product's bonding performance, aging resistance and yellowing resistance; nano-sized silica gel particles improve the sealing and pressure resistance of the hot melt adhesive.

[0008] Preferably, in step (1) of the present invention, the Fischer-Tropsch wax, polyethylene wax, plant-based plasticizer and antioxidant are added in sequence.

[0009] Preferably, in step (2) of the present invention, the metallocene-catalyzed polyolefin is added first, and after it is dissolved, the random polyolefin is added.

[0010] Preferably, in step (1) of the present invention, the Fischer-Tropsch wax is a Fischer-Tropsch wax with a low initial melting point, and the polyethylene wax is a high-temperature polyethylene wax.

[0011] Compared with the existing technology, the present invention has the following advantages and effects: the developed special hot melt adhesive can optimize the sealing, temperature resistance and fatigue resistance of the air filter enclosure, extend the life of the filter element, and reduce the frequency of user replacement; in addition, it optimizes the VOCs compliance of traditional hot melt adhesive to meet the higher standards of household air filter adhesive. Traditional EVA hot melt adhesive usually contains a small amount of human-perceptible VOCs, which does not meet the requirements of many household filter manufacturers and also does not meet the relevant inspection standards of many countries. The market currently lacks special hot melt adhesive products for household air filter enclosures with good performance and reasonable cost. The present invention can seize the initiative in the niche market and has broad market prospects.

[0012] This environmentally friendly hot melt adhesive, specifically designed for household air purifier filter cartridges, offers high sealing performance, temperature resistance (-20°C to 80°C), aging resistance, and low VOC emissions. Based on the principles of hot melt adhesive materials and the structural requirements of air filter cartridges, this product was developed through formulation optimization, process improvements, and performance testing. DETAILED DESCRIPTION

[0013] The present invention will be further described in detail below by way of examples. The following examples are intended to explain the present invention but the present invention is not limited to the following examples.

[0014] Example

[0015] The steps of the method for preparing the environmentally friendly hot melt adhesive for the filter element of the household air purifier in this embodiment are as follows:

[0016] (1) Add Fischer-Tropsch wax, polyethylene wax, plant-based plasticizer and antioxidant to the reactor. Fischer-Tropsch wax, polyethylene wax, plant-based plasticizer and antioxidant are added in sequence. Among them, 1 to 5 parts of Fischer-Tropsch wax, 5 to 13 parts of polyethylene wax, 10 to 30 parts of plant-based plasticizer, and 0.3 to 1 part of antioxidant; heat to 140°C to 160°C and stir at a stirring speed of 20 to 30 revolutions per minute until all melted and kept at a constant temperature; Fischer-Tropsch wax and polyethylene wax are used as viscosity and open time regulators to improve fluidity and dispersibility and enhance high temperature resistance; plant-based plasticizers can reduce VOC emissions; a small amount of high-quality antioxidants can slow down the aging of the material during the heating process and increase the life of the finished product in normal use. The Fischer-Tropsch wax in this embodiment can be a low initial melting point Fischer-Tropsch wax, and the polyethylene wax can be a high-temperature polyethylene wax. The low initial melting point Fischer-Tropsch wax and high-temperature polyethylene wax are clear to those skilled in the art. The antioxidant can be 1010 hindered phenol antioxidant, 168 organic phosphite antioxidant, 3114 trifunctional hindered phenol antioxidant, or 626 high temperature resistant organic phosphite antioxidant.

[0017] (2) Adding metallocene-catalyzed polyolefin and random polyolefin, wherein the metallocene-catalyzed polyolefin is 35-45 parts and the random polyolefin is 10-15 parts; first add the metallocene-catalyzed polyolefin, and after it is dissolved, add the random polyolefin and dissolve them one by one, stirring at a speed of 20-50 revolutions per minute until all are melted and the temperature is kept constant at 160°C to 180°C; the metallocene-catalyzed polyolefin has good flexibility and low temperature resistance, and the random polyolefin has good surface wettability and ductility, and has good compatibility with Fischer-Tropsch wax, polyethylene wax, and plant-based plasticizer.

[0018] (3) Add hydrogenated tackifying resin, pure monomer resin and nano-sized silica gel particles, wherein the hydrogenated tackifying resin is 40-50 parts, the pure monomer resin is 10-15 parts, and the nano-sized silica gel particles are 0.5-5 parts; reduce the stirring speed to 10-30 revolutions per minute, wait until it is fully stirred and uniform, introduce it into the screw extruder for extrusion and granulation, and obtain the environmentally friendly hot melt adhesive product; the melting temperature (recommended 110℃~130℃), extrusion rate and cooling conditions can be optimized to ensure the colloidal uniformity and dimensional stability of the environmentally friendly hot melt adhesive. The hydrogenated tackifying resin and pure monomer resin as tackifiers effectively improve the product's bonding performance, aging resistance and yellowing resistance; the nano-sized silica gel particles improve the hot melt adhesive's sealing and pressure resistance.

[0019] This application uses modified polyolefin environmentally friendly resin as the main material, taking into account bonding strength, low temperature resistance and flexibility; antioxidants and tackifying resins (such as pure monomer HC9, HC5, etc.) are added to improve aging resistance and bonding durability.

[0020] Nano-scale silicone particles are added as sealing enhancers to improve the sealing and pressure resistance of the hot melt adhesive; plant-based plasticizers are used to replace traditional petroleum-based ingredients as environmentally friendly additives to reduce VOC emissions; temperature-resistant regulators are achieved through compounding technology, allowing the hot melt adhesive to maintain viscoelasticity in the range of -20℃ to 80℃.

[0021] The specific formula of the embodiment of the present invention is shown in Table 1:

[0022] Table 1

[0023]

[0024] The present invention tested the performance of the environmentally friendly hot melt adhesive for household air purifier filter element prepared by the formula of Examples 1 to 6. The specific test results are shown in Table 2:

[0025] Table 2

[0026]

[0027] This application conducts the following basic performance tests on the environmentally friendly hot melt adhesive product:

[0028] 1) Melt viscosity, softening point, peel strength, shear strength, etc.;

[0029] 2) Temperature resistance test (high and low temperature cycle test);

[0030] 3) Environmental protection test (VOCs emission detection, odor detection).

[0031] The environmentally friendly hot melt adhesive products were verified for their application performance as follows:

[0032] 1) Compatibility test with mainstream air filter materials on the market (such as HEPA, activated carbon fiber);

[0033] 2) Testing the sealing performance under simulated actual working conditions (wind pressure, humidity changes);

[0034] 3) Accelerated aging test (85°C / 85% RH, 1000 hours) to evaluate the lifespan.

[0035] The following technical indicators are obtained:

[0036] Appearance: white semi-permeable granules;

[0037] Apparent viscosity: 6500±800mPa.s (180℃, rotational viscometer);

[0038] Softening point: 102±5℃ (according to GB / T 15332-1994 standard);

[0039] Opening time: ≤15s (according to HG / T 3716-2003 standard);

[0040] Peel strength: ≥15N / 2.5cm (refer to GB / T 2791-1995);

[0041] Shear strength: ≥1.5Mpa (refer to GB / T 7124-2008);

[0042] 110℃ dielectric loss factor (tanδ): ≥1;

[0043] Hot melt adhesive bonding strength ≥1.2MPa, sealing reaches IP68 level;

[0044] Environmental adaptability: Maintain stable performance for ≥168 hours under high temperature and high humidity (40℃ / 90% RH);

[0045] VOC emissions comply with GB / T 18883-2022 and BS EN13725-2022.

[0046] This application avoids VOCs in its raw material selection. All raw materials are non-volatile VOCs, particularly the main polymers, which are metallocene-catalyzed polyolefins and random polyolefins, used in conjunction with Fischer-Tropsch wax. The formulas used are predominantly high-softening point. Plant-based plasticizers replace traditional petroleum-based ingredients, significantly reducing VOC emissions. This application will help promote green upgrades in the air filtration industry, reduce pollution from traditional glues, and contribute to the achievement of the "dual carbon" goals.

[0047] The parts mentioned in this application are all parts by weight.

[0048] Although the present invention has been disclosed above with reference to the embodiments, it is not intended to limit the scope of protection of the present invention. Any changes and modifications made by any technician familiar with the technology without departing from the concept and scope of the present invention should fall within the scope of protection of the present invention.

Claims

1. A method for preparing an environmentally friendly hot melt adhesive for a household air purifier filter element, characterized in that: Here are the steps: (1) Adding Fischer-Tropsch wax, polyethylene wax, plant-based plasticizer and antioxidant into a reactor, wherein the Fischer-Tropsch wax is 1 to 5 parts, the polyethylene wax is 5 to 13 parts, the plant-based plasticizer is 10 to 30 parts, and the antioxidant is 0.3 to 1 part; heating to 140° C. to 160° C. and stirring at a stirring speed of 20 to 30 revolutions per minute until all are melted and the temperature is constant; (2) adding 35-45 parts of metallocene-catalyzed polyolefin and 10-15 parts of random polyolefin; dissolving them one by one, stirring at a speed of 20-50 revolutions per minute, until all are melted and the temperature is kept constant at 160°C to 180°C; (3) Add hydrogenated tackifying resin, pure monomer resin and nano-sized silica gel particles, wherein the hydrogenated tackifying resin is 40-50 parts, the pure monomer resin is 10-15 parts, and the nano-sized silica gel particles are 0.5-5 parts; reduce the stirring speed to 10-30 revolutions per minute, wait until it is fully stirred, introduce it into a screw extruder for extrusion and granulation, and obtain an environmentally friendly hot melt adhesive product.

2. The method for preparing an environmentally friendly hot melt adhesive for a household air purifier filter element according to claim 1, characterized in that: In the step (1), Fischer-Tropsch wax, polyethylene wax, plant-based plasticizer and antioxidant are added in sequence.

3. The method for preparing an environmentally friendly hot melt adhesive for a household air purifier filter element according to claim 1, characterized in that: In the step (2), the metallocene-catalyzed polyolefin is first added, and after it is dissolved, the random polyolefin is added.

4. The method for preparing an environmentally friendly hot melt adhesive for a household air purifier filter element according to claim 1, characterized in that: In the step (1), the Fischer-Tropsch wax is a Fischer-Tropsch wax with a low initial melting point, and the polyethylene wax is a high-temperature polyethylene wax.

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