Cool-feeling particle modified ES hot air non-woven material and preparation method thereof

Abstract

The invention discloses a cool-feeling particle modified non-woven material and a preparation method thereof, and aims at solving the technical problems that an existing cool-feeling material is poor in air permeability and not lasting in cool-feeling effect. According to the material, high-porosity hot air non-woven fabric is used as a base material, high-thermal-conductivity magnesium oxide nano-particles (the thermal conductivity is about 40 W / m.K) are firmly attached to the fiber surface and gaps of the base material through a polymer emulsion binder, and a microscopic thermal conduction network is formed. The preparation method comprises the following steps: preparing a cool-feeling particle suspension, dipping the base material in the suspension, applying a binder, carrying out thermocuring, and finally carrying out calendering treatment. By constructing an efficient heat conduction path, the instant contact cool feeling value (qmax is larger than or equal to 0.25 W / cm < 2 >) of the material is remarkably improved, and meanwhile by optimizing technological parameters, the excellent air permeability (larger than or equal to 2800mm / s) of the base material is completely reserved. The obtained material is remarkable in cooling effect, durable and washable, and can be widely applied to the fields of cooling clothes, bedding articles, cooling packaging and the like.

Description

Technical Field

[0001] The present invention relates to a cooling modified ES hot air nonwoven material, belonging to the technical field of hot air nonwoven material preparation. Background Art

[0002] Currently, most materials used for cooling clothing on the market use chemical treatment or surface coating methods, which usually result in a decrease in the air permeability of the material or a short-lasting cooling effect. In addition, although conventional hot air nonwoven materials have good softness and light weight, their thermal conductivity is low. The thermal conductivity of common fiber materials (such as polyester, polypropylene, etc.) is 0.1 to 0.4W / m·K, making it difficult to achieve efficient heat dissipation. Magnesium oxide (MgO) is a high thermal conductivity material with a thermal conductivity of approximately 40W / m·K. It has excellent thermal stability and can maintain its physical and chemical properties in high-temperature processing and use environments. ES hot air nonwoven fabrics have excellent air permeability. Adding magnesium oxide as cooling particles to hot air nonwoven fabrics can significantly improve the overall thermal conductivity of the material. However, magnesium oxide particles themselves are difficult to adhere to hot air nonwoven materials with long-term and strong adhesion. Therefore, how to prepare an ES hot air nonwoven material with good air permeability and excellent cooling performance has become a problem that needs to be solved. Summary of the Invention

[0003] In response to the defects or shortcomings in the existing technology, the present invention provides a hot air non-woven material modified with cooling particles. By introducing cooling particles into the ES hot air cloth substrate, the material can significantly improve the thermal conductivity and cooling effect while maintaining its softness and breathability, thereby solving the problems of insufficient breathability and short-lasting cooling effect in the existing technology.

[0004] A cooling particle-modified nonwoven material comprises: a nonwoven substrate, highly thermally conductive inorganic particles, and a binder; wherein the highly thermally conductive inorganic particles are attached to the fiber surface of the nonwoven substrate and / or filled in the fiber gaps via the binder to form a heat-conducting network.

[0005] The high thermal conductivity inorganic particles are metal oxide nanoparticles.

[0006] The metal oxide nanoparticles are magnesium oxide nanoparticles, and the particle size thereof ranges from 20 nm to 80 nm.

[0007] The nonwoven substrate is a hot air nonwoven fabric composed of thermoplastic bicomponent fibers, and the porosity thereof is greater than 85%.

[0008] The binder is a polymer emulsion, preferably an acrylic emulsion or a polyurethane emulsion.

[0009] The preparation method of the cooling particle modified nonwoven material comprises the following steps:

[0010] a) dispersing high thermal conductivity inorganic particles in a liquid medium to form a particle suspension;

[0011] b) immersing a nonwoven substrate in the particle suspension to adhere the inorganic particles to the substrate;

[0012] c) applying a binder to the nonwoven substrate having the inorganic particles attached thereto, and performing a heat curing treatment;

[0013] d) performing calendering on the solidified material.

[0014] In step a), the dispersion comprises mixing 2% to 10% of the total mass of the suspension with a dispersant under ultrasonic conditions.

[0015] The magnesium oxide nanoparticles are prepared by reacting a magnesium salt solution with an alkaline solution to generate magnesium hydroxide precipitates, which are washed and dried, and then calcined at a temperature of 500-700°C.

[0016] The temperature of the heat curing treatment in step c) is 100-150° C. and the time is 1-3 minutes.

[0017] In step c), an acrylic emulsion with a solid content of 30% to 45% is applied as a binder by spraying or dipping.

[0018] The washing retention rate of the cooling particles on the nonwoven material is predicted and calculated by the following formula:

[0019]

[0020] R max and k1 are parameters to be fitted, representing the theoretical limit adhesion rate and defect sensitivity parameter respectively; C is the solid content of the adhesive, and T is the curing temperature.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1) The cooling particles selected by the present invention are magnesium oxide inorganic nanoparticles, which have excellent thermal conductivity (thermal conductivity is about 40W / m·K), which is in sharp contrast to the hot air non-woven substrate (thermal conductivity <0.2W / m·K). By evenly distributing the particles in the substrate, the overall thermal conductivity of the material is greatly improved, so that when the human skin contacts the material, the surface heat can be quickly discharged, thereby enhancing the cooling experience. In addition, during the impregnation-curing process, the cooling particles are firmly bonded to the fiber surface through the binder, while filling the fiber gaps to form a microscopic heat-conducting network. This network structure further accelerates the transfer and diffusion of heat, achieving a uniform and stable cooling effect.

[0023] 2) The technology of the present invention does not change the pore structure of the existing hot air nonwoven material. The ES hot air nonwoven fabric originally has a high porosity (>85%) and good air permeability. During the modification process, the cooling particles prepared are nano-scale, mainly attached to the fiber surface or filling tiny pores, without causing obvious blockage of the overall structure, thereby maintaining the ventilation and permeability of the nonwoven fabric. And by optimizing the concentration of the added binder and the coating process, the uniform distribution of the cooling particles on the fiber surface is ensured, avoiding the decrease in air permeability caused by excessive particle accumulation, while maintaining the softness and elasticity of the fiber.

[0024] 3) Using an acrylic emulsion as a binder, its excellent adhesion properties ensure that the cooling particles are firmly embedded in the fiber surface or micropores. After hot air curing, the particle-binder-fiber bond forms a strong three-dimensional network, greatly enhancing the particles' adhesion and washability. Subsequent calendering not only improves the material's surface smoothness and feel, but also further strengthens the bond between the particles and the substrate, reducing the risk of particles falling off during washing and friction. DETAILED DESCRIPTION

[0025] The technical solution of this patent is as follows:

[0026] A cooling particle modified hot air nonwoven material consists of a base material hot air nonwoven fabric, cooling particles and a binder, wherein the cooling particles are uniformly distributed in the base material.

[0027] The cooling particles are inorganic nanoparticles with high thermal conductivity, preferably magnesium oxide nanoparticles, with a particle size ranging from 20 to 80 nm.

[0028] The cooling particles are magnesium oxide nanoparticles prepared by low-temperature coprecipitation combined with mild calcination. By strictly controlling the pH value (controlled at 10.5-11.0) and the reaction rate, magnesium oxide particles with more uniform particle size and larger specific surface area are obtained. Furthermore, controlling the calcination temperature at 600°C significantly reduces agglomeration. Compared with traditional calcination methods (>800°C), the particles adhere more firmly, improving the durability and thermal conductivity of the composite material. The preparation method includes:

[0029] The magnesium nitrate solution is reacted with the sodium hydroxide solution to generate magnesium hydroxide precipitate; after washing and drying, the precipitate is calcined at 500-700°C to generate magnesium oxide nanoparticles with a particle size range of 20-80 nm;

[0030] The thermal conductivity of the prepared magnesium oxide cooling particles is 40 W / m·K.

[0031] The base material is ES fiber hot air nonwoven fabric with a gram weight of 20-50g / m 2 .

[0032] The ES hot air nonwoven fabric has a fiber diameter of 3 to 10 μm and a porosity greater than 85%.

[0033] The binder is polyurethane latex or acrylate latex.

[0034] A method for preparing a cooling particle modified hot air nonwoven material comprises the following steps:

[0035] (1) preparing a cooling particle suspension;

[0036] (2) immersing the hot air nonwoven fabric in the suspension;

[0037] (3) hot air curing after applying the adhesive;

[0038] (4) The composite material is obtained by calendering treatment.

[0039] The magnesium oxide cooling particles are dispersed in deionized water at a mass fraction of 2% to 10%.

[0040] 0.5% to 1% of PVP dispersant was added to the obtained suspension, and ultrasonic dispersion (40 kHz) was used for 30 minutes to uniformly disperse the magnesium oxide particles to form a stable suspension.

[0041] ES hot air nonwoven fabric was used as the substrate and cut into 40 cm × 40 cm samples. The samples were immersed in the prepared magnesium oxide suspension, and the liquid surface was kept soaking the material surface. After soaking for 6 hours, the samples were taken out and lightly dehydrated at 80 ° C to remove excess water.

[0042] Acrylate emulsion is used as a binder, and 10% to 20% of the binder is applied to the impregnated nonwoven fabric through a spraying or dipping process.

[0043] The impregnated, modified, and binder-coated ES nonwoven fabric was hot-air cured at 100-150°C for 1-3 minutes to produce a modified ES hot-air nonwoven fabric. The hot-air-cured sample was then post-processed by calendering the dried material to enhance surface smoothness, particle adhesion, and uniform distribution of the cooling particles.

[0044] The cooling particle-modified hot air nonwoven material can be applied to cooling clothing, bedding or cooling packaging materials.

[0045] Example 1:

[0046] Polyvinyl pyrrolidone (PVP) was selected to improve the dispersion stability of magnesium oxide particles in water, and the preparation experiment was carried out:

[0047] The weight is 30g / m 2ES hot air nonwoven fabric is used as the base material, with a thickness of 0.3 mm and a porosity of about 85%.

[0048] A low-temperature co-precipitation method combined with mild calcination was used to react magnesium nitrate solution with sodium hydroxide solution to generate magnesium hydroxide precipitate. The magnesium hydroxide was then washed and dried, and then calcined at 600°C to generate magnesium oxide nanoparticles with an average particle size of 30nm.

[0049] The generated magnesium oxide particles were added to deionized water at a mass ratio of 8%, and 0.5% of PVP dispersant was added. Ultrasonic dispersion (40 kHz) was used for 2 h to uniformly disperse the magnesium oxide particles and form a stable suspension.

[0050] The ES hot air nonwoven fabric was cut into 40cm×40cm samples and immersed in the prepared magnesium oxide suspension. The liquid surface was kept soaking the material surface for 6 hours to ensure that the particles were evenly attached to the fiber surface and pores. The sample was taken out and slightly dehydrated at 80℃ to remove excess water to obtain the impregnation modified hot air nonwoven material.

[0051] Acrylate emulsion (solid content 40%) was selected as the binder, and the impregnated nonwoven fabric was sprayed with the binder, and the spraying amount was controlled at 100g / m 2 , and then cured at 100°C for 2 minutes to firmly bond the magnesium oxide particles to the surface of the substrate fiber to form a modified material.

[0052] The cured material is then passed through a calender at 60°C for a slight calendering treatment to enhance surface smoothness and improve hand feel.

[0053] The sample of Example 1 was subjected to performance testing:

[0054] Cooling performance: Using a contact cooling tester (GB / T35263-2017), the cooling value (qmax) is increased to 0.25W / cm2, which is about 50% higher than that of the unmodified material.

[0055] Breathability: tested with an air permeability tester (GB / T5453-1997), the air permeability is 2800mm / s, which is basically the same as the original material and does not affect the comfort of the material.

[0056] Durability: Wash in a 40±2°C water bath at 40±2 rpm for 45 minutes. After washing, carefully remove the sample to avoid excessive friction. Dry the sample in a 70±2°C oven to constant weight, which counts as one wash. After 30 washes, weigh the sample before and after washing, drying it, and then weighing it. The cooling particle adhesion rate remained above 92%, demonstrating excellent durability.

[0057] Application Effect

[0058] The modified non-woven material was used in the test of cool mattress fabrics. According to user experience feedback, the material has a significant cooling effect when in contact with the skin and has excellent breathability, meeting the cooling demand.

[0059] Example 2

[0060] Based on the preferred parameters of Example 1 (8% magnesium oxide addition, 0.5% PVP dispersant, 2 hours of ultrasound, and calendering at 60° C.), other conditions were fixed, and the binder solid content and curing temperature were adjusted to conduct four comparative experiments:

[0061] Group 1: solid content 30%, curing temperature 120℃

[0062] Group 2: solid content 45%, curing temperature 80℃

[0063] Group 3: solid content 30%, curing temperature 80℃

[0064] Group 4: solid content 40%, curing temperature 100°C (same as Example 1)

[0065] Group <![CDATA[Cooling sensation value (qmax, W / cm 2 )]]> Air permeability (mm / s) Particle adhesion rate after washing (%) Group 1 0.22 2600 85 Group 2 0.24 2300 88 Group 3 0.20 2700 78 Group 4 0.25 2800 92

[0066] When cured at 100°C, a 40% solid content binder forms a uniform film that fully encapsulates the magnesium oxide particles and tightly adheres to the fibers, creating a more complete thermal network. A moderate solid content of 40% prevents the binder from clogging pores, while a higher solid content of 45% results in a decrease in air permeability. A curing temperature of 100°C fully crosslinks the acrylic emulsion, strengthening the three-dimensional bond between particles, binder, and fibers. If the binder is insufficiently crosslinked due to low-temperature curing, the adhesion rate of Group 3 is only 78%. A high temperature of 120°C causes the low-concentration binder to rapidly form a film, resulting in incomplete particle encapsulation, broken thermal paths, and a decrease in coolness. High temperatures also cause some fibers to shrink, pores to slightly damage, and air permeability to decrease. A high solid content binder of 45% overfills the pores, leading to a decrease in air permeability. A curing temperature of 80°C is insufficient to activate complete crosslinking of the binder, resulting in insufficient particle adhesion strength and a decrease in adhesion.

[0067] Based on the overall process of impregnating cooling particles and spraying adhesive in this patent, the present invention also proposes a microporous coverage model to predict the water-washing adhesion rate of cooling particles during the adhesive application process. Under the most perfect conditions, the solid content is extremely high, which means that the film-forming material is dense, and the curing temperature is also extremely high, which means that the cross-linking reaction is complete and the molecular chain is fully stretched. At this time, the obtained coating will be defect-free, and its adhesion rate will reach a theoretical limit value, which is defined as the theoretical limit adhesion rate R maxIn actual processes, perfect conditions cannot be achieved. The limitations of solid content and curing temperature are the two main sources of defects in the final coating. These defects can be understood as microscopic pores, incompletely reacted functional groups, uneven cross-linking networks, etc. These defects together constitute the "porous network" structure of the coating, weakening the bonding force between the coating and the substrate, resulting in a decrease in adhesion rate. The lower the solid content, the higher the solvent content. During the curing process, the volatilization of a large amount of solvent is more likely to leave micropores in the coating, resulting in a loose structure. Therefore, the amount of defects introduced by insufficient solid content, the lower the curing temperature, the less molecular thermal motion energy, the less sufficient the chemical cross-linking reaction, and the inability of the polymer chain to fully stretch and fill the gaps. Therefore, the amount of defects introduced by insufficient temperature. Assume that the negative effects of these two defects on the total adhesion rate are linearly superimposed. The actual adhesion rate R can be expressed as:

[0068] R=R max -R loss

[0069] R loss is the loss of adhesion due to defects. R loss It should be proportional to the total amount of defects in the system, and a proportional coefficient k1 is introduced, which reflects the sensitivity of the system to defects, that is, how much adhesion loss will be caused by each unit "defect amount".

[0070] R loss =k1·D total

[0071] Total defect amount D total It is the superposition of two sources, which includes the defect portion D which is inversely proportional to the solid content C C , and the defect portion D is inversely proportional to the curing temperature T T , the total defect can be expressed as Then we get:

[0072]

[0073] After fitting the above test results, k1 and R are regressed. max The theoretical values ​​and predicted values ​​of the four groups of experiments are shown in the following table. It can be seen that the model proposed in the present invention can effectively predict the water washing retention rate of the nonwoven material obtained by the process of the present invention.

[0074] Experimental value R (%) Model prediction value R (%) Relative error (%) Group 1 85 83.34 1.95 Group 2 88 90.43 2.76 Group 3 78 79.08 1.39 Group 4 92 90.15 2.01

[0075] By substituting the water washing retention rate parameters of the materials obtained under other preparation parameter conditions into the above equation for calculation, the verification results are as follows:

[0076] Solid content (%) Curing temperature (℃) Experimental value R (%) Model prediction value R (%) Relative error (%) Group 1 35 75 80 83.10 3.07 Group 2 40 75 88 86.74 1.43

[0077] Example 3

[0078] The specific composite material preparation process parameter ranges are shown in Table 1:

[0079]

[0080]

Claims

1. A cooling particle modified nonwoven material, characterized in that: include: Non-woven substrate, high thermal conductivity inorganic particles, and a binder; wherein the high thermal conductivity inorganic particles are attached to the fiber surface of the nonwoven substrate and / or filled in the fiber gaps through the binder to form a thermal conductive network.

2. The cooling particle modified nonwoven material according to claim 1, characterized in that: The high thermal conductivity inorganic particles are metal oxide nanoparticles.

3. The cooling particle modified nonwoven material according to claim 2, characterized in that: The metal oxide nanoparticles are magnesium oxide nanoparticles, and the particle size thereof ranges from 20 nm to 80 nm.

4. The cooling particle modified nonwoven material according to claim 1, characterized in that: The nonwoven substrate is a hot air nonwoven fabric composed of thermoplastic bicomponent fibers, and the porosity thereof is greater than 85%.

5. The cooling particle modified nonwoven material according to claim 1, characterized in that: The binder is a polymer emulsion, preferably an acrylic emulsion or a polyurethane emulsion.

6. A method for preparing a nonwoven material modified with cooling particles according to any one of claims 1 to 5, characterized in that: The following steps are involved: a) dispersing high thermal conductivity inorganic particles in a liquid medium to form a particle suspension; b) immersing a nonwoven substrate in the particle suspension to adhere the inorganic particles to the substrate; c) applying a binder to the nonwoven substrate with the inorganic particles attached thereto, and performing a heat curing process; d) performing a calendering process on the cured material.

7. The preparation method according to claim 6, characterized in that In step a), the dispersion comprises mixing 2% to 10% of the total mass of the suspension with a dispersant under ultrasonic conditions.

8. The preparation method according to claim 7, characterized in that The magnesium oxide nanoparticles are prepared by reacting a magnesium salt solution with an alkaline solution to generate magnesium hydroxide precipitates, which are washed and dried, and then calcined at a temperature of 500-700°C.

9. The preparation method according to claim 6, characterized in that The temperature of the heat curing treatment in step c) is 100-150° C., time is 1-3 minutes; in step c), applying an acrylic emulsion with a solid content of 30% to 45% as a binder by spraying or dipping.

10. The preparation method according to claim 6, characterized in that The washing retention rate of the cooling particles on the nonwoven material is predicted and calculated by the following formula: R max and k1 are parameters to be fitted, representing the theoretical limit adhesion rate and defect sensitivity parameter respectively; C is the solid content of the adhesive, and T is the curing temperature.

Images