Breathable antibacterial PVC foam pad and preparation method thereof

Abstract

The invention particularly relates to a breathable and antibacterial PVC foam pad and a preparation method thereof. The PVC foam pad comprises the following raw materials in parts by weight: 90-100 parts of PVC resin, 10-30 parts of a plasticizer, 3-6 parts of a heat stabilizer, 5-10 parts of a foaming agent, 10-20 parts of breathable filler, 1-6 parts of an antibacterial agent, 5-15 parts of a thermoplastic elastomer and 1-3 parts of a lubricant. Wherein the breathable filler and the PVC resin matrix form chemical bonding, and due to the addition of the antibacterial agent and the thermoplastic elastomer and the combination of UV curing treatment, an in-situ antibacterial network is constructed, so that the long-acting antibacterial and bacteriostatic properties of the PVC foam pad are remarkably improved; furthermore, the unique foaming agent is combined to form a multi-scale foam structure, the foaming uniformity is improved by combining gradient depressurization foaming, and the air permeability, the impact resistance and the wear resistance of the PVC foam pad are also favorably improved under the combined action of the foaming agent and the air-permeable filler.

Description

Technical Field

[0001] The present invention relates to the technical field of household foam pad preparation, and particularly relates to a breathable and antibacterial PVC foam pad and a preparation method thereof. Background Art

[0002] PVC (polyvinyl chloride) foam pads have been widely used in many fields such as daily life and industrial production due to their low cost, soft texture, strong processability, etc., such as household floor mats, yoga mats, industrial anti-slip mats, etc. However, there are many defects in existing PVC foam pads that limit their further promotion and application.

[0003] On the one hand, the breathability of traditional PVC foam pads is poor. When used in a humid environment or in contact with the human body for a long time, heat and moisture are difficult to dissipate, which easily makes the user feel stuffy and greatly affects the comfort of use. Moreover, this stuffy and humid environment provides a breeding ground for bacteria, molds and other microorganisms. After long-term use, the mat is prone to generate peculiar smells, which is not only unhygienic but also may pose a potential threat to human health.

[0004] On the other hand, as the use time prolongs, the anti-slip performance of PVC foam pads will gradually decline. In some occasions with high anti-slip requirements, such as floor mats used in bathrooms, kitchens, etc., the reduction of anti-slip performance is likely to cause safety accidents. At the same time, the wear resistance of ordinary PVC foam pads is also not satisfactory. Frequent friction will cause the surface of the mat to wear and deform, shortening its service life. Therefore, developing a PVC foam pad with good breathability, wear resistance and antibacterial properties has important practical significance and broad market prospects. Summary of the Invention

[0005] The purpose of the present invention is to provide a breathable and antibacterial PVC foam pad and a preparation method thereof to solve the above-mentioned deficiencies of the prior art.

[0006] The purpose of the present invention is achieved through the following technical solutions: The present invention provides a breathable and antibacterial PVC foam pad, which comprises the following raw materials in parts by weight: 90-100 parts of PVC resin, 10-30 parts of plasticizer, 3-6 parts of heat stabilizer, 5-10 parts of foaming agent, 10-20 parts of breathable filler, 1-6 parts of antibacterial agent, 5-15 parts of thermoplastic elastomer, and 1-3 parts of lubricant.

[0007] Furthermore, the plasticizer is at least one of dioctyl terephthalate, polybutylene adipate, polyhexylene adipate, and epoxidized soybean oil. Preferably, the plasticizer is a compound of dioctyl terephthalate and polyhexylene adipate in a mass ratio of 1:1.

[0008] Furthermore, the heat stabilizer is at least one of magnesium aluminum hydrotalcite, lanthanum stearate, calcium stearate, zinc stearate, epoxy soybean oil, and phosphite.

[0009] Furthermore, the foaming agent is at least one of azodicarbonamide, azobisisobutyronitrile, p-toluenesulfonyl hydrazide, and / or at least one of nano zinc oxide, citric acid, sodium bicarbonate, and polycarboxylic acid foaming agents. Preferably, the foaming agent is a compound of azodicarbonamide, nano zinc oxide, and sodium bicarbonate in a mass ratio of 4-5:2:1.

[0010] Furthermore, the breathable filler is a hydrophobically and oleophobically modified cellulose-based aerogel, and the preparation method of the hydrophobically and oleophobically modified cellulose-based aerogel comprises the following steps: adding 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane to the ethanol aqueous solution of pretreated cellulose nanofibers and stirring thoroughly, adding acetic acid to adjust the pH of the system to 4.5, stirring for 2-3 hours under heating conditions, dispersing in ethanol after centrifugal washing, and then adding an acetone solution of perfluoroalkylethyl acrylate thereto, followed by adding an organic tin catalyst, heating and ultrasonically reacting for 2-2.5 hours, preparing a suspension after centrifugal washing, transferring to a mold for precooling with liquid nitrogen, and then transferring to a freeze dryer for freeze drying at -60-80°C for 24-48 hours to obtain the hydrophobically and oleophobically modified cellulose-based aerogel.

[0011] In the present invention, the pretreatment of cellulose nanofibers can be carried out by TEMPO oxidation or mechanical treatment, so that the carboxyl and hydroxyl groups on the surface of the cellulose nanofibers are increased, which is convenient for grafting with perfluoroalkyl ethyl acrylate, and the cross-linked network is formed by epoxy ring opening to enhance the interfacial bonding force. By introducing perfluoroalkyl ethyl acrylate, the surface energy of the cellulose nanofibers is significantly reduced, and a porous structure with uniform pores is formed under directional freezing, thereby obtaining a hydrophobic, oleophobic and porous cellulose-based aerogel.

[0012] Furthermore, the antibacterial agent is a microsphere-loaded nanosilver antibacterial agent. The preparation method of the microsphere-loaded nanosilver antibacterial agent comprises the following steps: completely dissolving catechol in deionized water, adding ammonia water and formaldehyde solution in sequence, heating reaction to obtain a suspension, and washing by centrifugation to obtain microspheres; dispersing the microspheres in a 3-aminopropyltriethoxysilane-ethanol solution for reflux reaction, washing by centrifugation and drying, and then dispersing them in water, adding silver nitrate solution and stirring in the dark, and then adding ascorbic acid and continuing stirring, and when the solution changes from colorless to brownish yellow, washing by centrifugation and drying to obtain the microsphere-loaded nanosilver antibacterial agent.

[0013] In the present invention, the microsphere-loaded silver nanoparticles can make the silver nanoparticles uniformly dispersed in the microspheres, giving full play to the broad-spectrum antibacterial activity of the silver nanoparticles to a greater extent, and making the silver nanoparticles not easily fall off due to long-term immersion in water or frequent rinsing, thereby achieving the effect of long-term antibacterial.

[0014] Furthermore, the thermoplastic elastomer is a polycarbonate with cinnamate groups in the side chain. In the present invention, the preparation method of the polycarbonate with cinnamate groups in the side chain is as follows: Dissolve the polycarbonate in dichloromethane, add an excessive amount of ethylene glycol and tetrabutyl titanate, and heat under reflux for 5-6 h. Then precipitate in methanol, dry and filter. The obtained product is dissolved in dichloromethane again. Under nitrogen protection, cool the reaction system to below 0 °C using an ice bath or a low-temperature reactor. Dissolve cinnamoyl chloride in dichloromethane and add it to the reaction system. Then successively add 4-dimethylaminopyridine and triethylamine. After reacting for 30-60 min, transfer to room temperature and continue to react in the dark for 1.5-3 h. Wash the reaction solution successively with dilute hydrochloric acid and deionized water. After removing the solvent by rotary evaporation of the oil phase, dry it under vacuum to obtain the polycarbonate with cinnamate groups in the side chain.

[0015] Furthermore, the lubricant is at least one of stearic acid, calcium stearate, glycerol monostearate, polyethylene wax, oxidized polyethylene wax, and ethylene bisstearamide. Preferably in the present invention, the lubricant is a compound prepared by compounding calcium stearate and oxidized polyethylene wax in a mass ratio of 2:1.

[0016] The present invention also provides a preparation method of the above-mentioned PVC foamed pad, which includes the following steps:

[0017] Step S1: Dry the breathable filler in a vacuum oven for 2-4 h, then place it in an ethanol solution containing a silane coupling agent and ultrasonicate for 10-30 min, and dry it for later use;

[0018] Step S2: Premix the thermoplastic elastomer and a small amount of plasticizer, and swell at 80-90 °C for 1-3 h, and set aside;

[0019] Step S3: Add the PVC resin and the remaining plasticizer to a kneader, control the temperature at 120-130 °C and premix for 5-10 min, then add the heat stabilizer and the lubricant, raise the temperature to 130-140 °C and mix at high speed for 3-6 min. Subsequently, add the breathable filler treated in Step S1, the thermoplastic elastomer treated in Step S2, and the antibacterial agent, and raise the temperature to 150-160 °C under nitrogen protection and mix at high speed for 5-8 min to make them fully and uniformly mixed;

[0020] Step S4: Feed the mixture obtained in Step S3 into a twin-screw extruder for extrusion molding. The temperatures of each section of the extruder are set as follows: Zone 1: 140 - 155°C, Zone 2: 155 - 170°C, Zone 3: 170 - 185°C, Zone 4: 180 - 200°C. A foaming agent is injected in Zone 3, and gradient pressure reduction foaming is carried out in Zone 4. The head pressure is reduced from 10 - 15 MPa to 5 MPa, and then through cooling and shaping and traction cutting, the initial product of the PVC foamed pad is obtained.

[0021] Step S5: Place the initial product of the PVC foamed pad obtained in Step S4 under ultraviolet light for irradiation for 10 - 15 min, then transfer it to a hot air oven at 78 - 82°C for treatment for 1 - 2 h, and finally place it at room temperature for 20 - 24 h to obtain the finished product of the PVC foamed pad.

[0022] The beneficial effects of the present invention are as follows: The present invention provides a breathable and antibacterial PVC foamed pad and its preparation method. By forming a chemical bond between the hydrophobic and oleophobic modified cellulose-based aerogel and the PVC resin matrix, and due to the addition of microsphere-loaded nano-silver antibacterial agent and thermoplastic elastomer, combined with UV curing treatment, an in-situ antibacterial network is constructed, significantly improving the long-term antibacterial and bacteriostatic properties of the PVC foamed pad; furthermore, a unique combination of foaming agents forms a multi-scale pore structure, combined with gradient pressure reduction foaming to improve the uniformity of foaming, and also helps to enhance the breathability, impact resistance and wear resistance of the PVC foamed pad in cooperation with the breathable filler. Detailed Embodiments

[0023] For the convenience of understanding by those skilled in the art, the present invention will be further described below in conjunction with embodiments. The content mentioned in the embodiments does not limit the present invention.

[0024] Embodiment 1

[0025] This embodiment provides a breathable and antibacterial PVC foamed pad, which comprises the following raw materials in parts by weight: 90 parts of PVC resin, 15 parts of plasticizer, 3 parts of heat stabilizer, 6 parts of foaming agent, 12 parts of breathable filler, 2 parts of antibacterial agent, 6 parts of thermoplastic elastomer, and 1.5 parts of lubricant.

[0026] Further, the plasticizer is a compound of dioctyl terephthalate and poly(hexylene adipate) with a mass ratio of 1:1.

[0027] Further, the heat stabilizer is a compound of epoxidized soybean oil and lanthanum stearate with a mass ratio of 3:1.

[0028] Further, the foaming agent is a compound of azodicarbonamide, nano-zinc oxide and sodium bicarbonate with a mass ratio of 4:2:1.

[0029] Further, the breathable filler is a cellulose-based aerogel modified with hydrophobic and oleophobic properties. The preparation method of the cellulose-based aerogel modified with hydrophobic and oleophobic properties comprises the following steps: adding 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane into an ethanol aqueous solution of pretreated cellulose nanofibers according to a mass ratio of 10:1, stirring well, adding acetic acid to adjust the pH of the system to 4.5, stirring at 65 °C for 2 h, centrifuging and washing, then dispersing in ethanol, adding a acetone solution of perfluoroalkyl ethyl acrylate with a mass ratio of 5:1 thereto, subsequently adding 0.1 wt% of an organotin catalyst, carrying out an ultrasonic reaction at 50 °C for 2 h, centrifuging and washing, then preparing a suspension, transferring it to a mold and pre-cooling it with liquid nitrogen for 10 min, and then transferring it to a freeze dryer to carry out freeze drying at -60 °C and under a condition of less than 10 Pa for 24 h, thus obtaining the cellulose-based aerogel modified with hydrophobic and oleophobic properties.

[0030] Further, the antibacterial agent is a microsphere-loaded nano-silver antibacterial agent. Among them, the preparation method of the microsphere-loaded nano-silver antibacterial agent comprises the following steps: completely dissolving 1 g of catechol in 100 mL of deionized water, sequentially adding 2 mL of ammonia water and 1.5 mL of formaldehyde solution, heating and reacting at 60 °C for 6 h to obtain a suspension, and centrifuging and washing to obtain microspheres; dispersing the microspheres in a 3-aminopropyltriethoxysilane-ethanol solution (5% v / v) and carrying out a reflux reaction for 2 h, centrifuging, washing and drying, then dispersing in water again, adding a silver nitrate solution according to a mass ratio of 1:1.7, stirring in the dark, then adding an equal amount of ascorbic acid and continuing to stir for 1 h. After the solution changes from colorless to brownish yellow, centrifuging, washing and drying to obtain the microsphere-loaded nano-silver antibacterial agent.

[0031] Further, the thermoplastic elastomer is a polycarbonate with cinnamate groups in the side chain. In the present invention, the preparation method of the polycarbonate with cinnamate groups in the side chain is specifically as follows: dissolving polycarbonate with Mn of 35000 in dichloromethane according to a mass-to-volume ratio of 1:10, adding an excessive amount of ethylene glycol (with a mass-to-volume ratio with polycarbonate of 1:2) and 0.5 wt% of tetrabutyl titanate, heating and refluxing for 5.5 h, then precipitating in methanol, drying and filtering. The obtained product is dissolved in dichloromethane again. Under nitrogen protection, the reaction system is cooled to below 0 °C by using an ice bath. Cinnamoyl chloride is dissolved in dichloromethane according to a mass-to-volume ratio of 10:1 and added to the reaction system, then 4-dimethylaminopyridine and triethylamine are sequentially added. After reacting for 30 min, it is transferred to room temperature and continues to react in the dark for 2 h. The reaction solution is washed with dilute hydrochloric acid and deionized water in sequence. The oil phase is rotary evaporated to remove the solvent and then vacuum dried to obtain the polycarbonate with cinnamate groups in the side chain. Among them, the molar ratio of the polycarbonate pretreatment product to cinnamoyl chloride, 4-dimethylaminopyridine and triethylamine is 1:1.2:0.1:1.5.

[0032] Furthermore, the lubricant is compounded by calcium stearate and oxidized polyethylene wax in a mass ratio of 2:1.

[0033] Example 2

[0034] The present embodiment provides a breathable and antibacterial PVC foam pad, comprising the following raw materials in parts by weight: 100 parts of PVC resin, 25 parts of plasticizer, 4 parts of heat stabilizer, 7 parts of foaming agent, 15 parts of breathable filler, 3 parts of antibacterial agent, 10 parts of thermoplastic elastomer, and 3 parts of lubricant.

[0035] Furthermore, the plasticizer is compounded by dioctyl terephthalate and poly(hexylene adipate) in a mass ratio of 1:1.

[0036] Furthermore, the heat stabilizer is compounded by epoxy soybean oil, calcium stearate and zinc stearate in a mass ratio of 3:1:1.

[0037] Furthermore, the foaming agent is compounded by azodicarbonamide, nano zinc oxide and sodium bicarbonate in a mass ratio of 5:2:1.

[0038] Furthermore, the breathable filler is a hydrophobically and oleophobically modified cellulose-based aerogel, and the preparation method of the hydrophobically and oleophobically modified cellulose-based aerogel comprises the following steps: adding 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane to the ethanol aqueous solution of pretreated cellulose nanofibers at a mass ratio of 10:1 and stirring thoroughly, adding acetic acid to adjust the pH of the system to 4.5, stirring at 65°C for 2 hours, centrifuging and washing, and dispersing in ethanol, and then adding an acetone solution of perfluoroalkylethyl acrylate at a mass ratio of 5:1, followed by adding 0.1wt% of an organic tin catalyst, ultrasonically reacting at 50°C for 2 hours, and preparing a suspension after centrifugal washing, transferring to a mold for precooling with liquid nitrogen for 10 minutes, and then transferring to a freeze dryer for freeze drying at -60°C and less than 10Pa for 24 hours to obtain the hydrophobically and oleophobically modified cellulose-based aerogel.

[0039] Furthermore, the antibacterial agent is a microsphere-loaded nanosilver antibacterial agent. The preparation method of the microsphere-loaded nanosilver antibacterial agent comprises the following steps: 1g of catechol is completely dissolved in 100mL of deionized water, 2mL of ammonia water and 1.5mL of formaldehyde solution are added in sequence, and the suspension is obtained by heating at 60°C for 6h, and the microspheres are obtained by centrifugal washing; the microspheres are dispersed in 3-aminopropyltriethoxysilane-ethanol solution (5% v / v) for reflux reaction for 2h, and then dispersed in water after centrifugal washing and drying, and silver nitrate solution is added at a mass ratio of 1:1.7 and stirred in the dark, and then an equal amount of ascorbic acid is added and stirred for 1.5h, and when the solution changes from colorless to brownish yellow, the microsphere-loaded nanosilver antibacterial agent is obtained by centrifugal washing and drying.

[0040] Further, the thermoplastic elastomer is a polycarbonate with cinnamate groups in the side chain. In the present invention, the preparation method of the polycarbonate with cinnamate groups in the side chain is specifically as follows: Dissolve polycarbonate with Mn of 35000 in dichloromethane at a mass-to-volume ratio of 1:10, add excessive ethylene glycol (with a mass-to-volume ratio of 1:2 to polycarbonate) and 0.5 wt% tetrabutyl titanate, and heat under reflux for 5.5 h. Then precipitate in methanol and dry and filter. The obtained product is dissolved in dichloromethane again. Under nitrogen protection, cool the reaction system to below 0 °C using an ice bath. Dissolve cinnamoyl chloride in dichloromethane at a mass-to-volume ratio of 10:1 and add it to the reaction system. Then successively add 4-dimethylaminopyridine and triethylamine. After reacting for 30 min, transfer to room temperature and continue to react in the dark for 2 h. Wash the reaction solution successively with dilute hydrochloric acid and deionized water. After removing the solvent by rotary evaporation of the oil phase, dry it under vacuum to obtain the polycarbonate with cinnamate groups in the side chain. Among them, the molar ratio of the polycarbonate pretreatment product to cinnamoyl chloride, 4-dimethylaminopyridine, and triethylamine is 1:1.2:0.1:1.5.

[0041] Further, the lubricant is compounded from calcium stearate and oxidized polyethylene wax at a mass ratio of 2:1.

[0042] Example 3

[0043] This example provides a breathable and antibacterial PVC foam pad, which comprises the following raw materials in parts by weight: 100 parts of PVC resin, 30 parts of plasticizer, 5 parts of heat stabilizer, 8 parts of foaming agent, 16 parts of breathable filler, 4 parts of antibacterial agent, 12 parts of thermoplastic elastomer, and 3 parts of lubricant.

[0044] Further, the plasticizer is compounded from dioctyl terephthalate and poly(hexamethylene adipate) at a mass ratio of 1:1.

[0045] Further, the heat stabilizer is compounded from epoxidized soybean oil, calcium stearate, and zinc stearate at a mass ratio of 3:1:1.

[0046] Further, the foaming agent is compounded from azodicarbonamide, nano-zinc oxide, and sodium bicarbonate at a mass ratio of 4:2:1.

[0047] Further, the breathable filler is a cellulose-based aerogel modified with hydrophobic and oleophobic properties. The preparation method of the cellulose-based aerogel modified with hydrophobic and oleophobic properties includes the following steps: Add 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane to the ethanol aqueous solution of pretreated cellulose nanofibers at a mass ratio of 10:1, stir well, add acetic acid to adjust the pH of the system to 4.5, stir at 65°C for 2 h, centrifuge and wash, then disperse in ethanol. Then add an acetone solution of perfluoroalkyl ethyl acrylate at a mass ratio of 5:1, and subsequently add 0.1 wt% of an organotin catalyst. React under ultrasonic conditions at 50°C for 2 h, centrifuge and wash, then prepare a suspension, transfer it to a mold and pre-cool it with liquid nitrogen for 10 min, and then transfer it to a freeze dryer to freeze-dry at -60°C and under a condition of less than 10 Pa for 24 h to obtain the cellulose-based aerogel modified with hydrophobic and oleophobic properties.

[0048] Further, the antibacterial agent is a microsphere-loaded nano-silver antibacterial agent. Among them, the preparation method of the microsphere-loaded nano-silver antibacterial agent includes the following steps: Completely dissolve 1 g of catechol in 100 mL of deionized water, sequentially add 2 mL of ammonia water and 1.5 mL of formaldehyde solution, heat and react at 60°C for 6 h to obtain a suspension, and obtain microspheres after centrifugation and washing; Disperse the microspheres in a 3-aminopropyltriethoxysilane-ethanol solution (5% v / v) and reflux for 2 h, centrifuge, wash and dry, then disperse in water again, add a silver nitrate solution according to a mass ratio of 1:1.8, stir in the dark, then add an equal amount of ascorbic acid and continue to stir for 1.5 h. When the solution changes from colorless to brownish-yellow, obtain the microsphere-loaded nano-silver antibacterial agent after centrifugation, washing and drying.

[0049] Further, the thermoplastic elastomer is a polycarbonate with cinnamate groups in the side chain. In the present invention, the preparation method of the polycarbonate with cinnamate groups in the side chain is specifically as follows: Dissolve polycarbonate with a Mn of 35000 in dichloromethane at a mass-to-volume ratio of 1:10, add an excessive amount of ethylene glycol (with a mass-to-volume ratio of 1:2 to polycarbonate) and 0.5 wt% of tetrabutyl titanate, heat and reflux for 5.5 h, then precipitate in methanol, dry and filter. The obtained product is dissolved in dichloromethane again. Under nitrogen protection, cool the reaction system to below 0°C using an ice bath. Dissolve cinnamoyl chloride in dichloromethane at a mass-to-volume ratio of 10:1 and add it to the reaction system, then sequentially add 4-dimethylaminopyridine and triethylamine. After reacting for 30 min, transfer it to room temperature and continue to react in the dark for 2 h. Wash the reaction solution with dilute hydrochloric acid and deionized water in sequence. After removing the solvent by rotary evaporation of the oil phase, dry it under vacuum to obtain the polycarbonate with cinnamate groups in the side chain. Among them, the molar ratio of the polycarbonate pretreatment product to cinnamoyl chloride, 4-dimethylaminopyridine and triethylamine is 1:1.2:0.1:1.5.

[0050] Further, the lubricant is compounded from calcium stearate and oxidized polyethylene wax with a mass ratio of 2:1.

[0051] Comparative Example 1

[0052] The difference between this comparative example and Example 2 lies in that azodicarbonamide is used as the foaming agent to replace the foaming agent in Example 2, and in the preparation method of the PVC foamed pad, the pressure maintenance in the fourth zone is the same as that in the first three zones in Step S4.

[0053] Comparative Example 2

[0054] The difference between this comparative example and Example 2 lies in that a commercial nano-silver antibacterial agent (Lanfeng Auxiliary Co., Ltd., Foshan City) is used to replace the microsphere-loaded nano-silver antibacterial agent in Example 2.

[0055] Comparative Example 3

[0056] The difference between this comparative example and Example 2 lies in that polycarbonate is used to replace the thermoplastic elastomer in Example 2.

[0057] Comparative Example 4

[0058] The difference between this comparative example and Example 2 lies in that white carbon black is used to replace the breathable filler in Example 2.

[0059] Performance Test

[0060] Perform performance tests on the PVC foamed pads prepared in the above Examples 1-3 and Comparative Examples 1-4 according to the following method: The tensile strength is tested according to ISO 1798, the air permeability is tested according to ASTF D737, the antibacterial rate is tested according to ISO22196 (Escherichia coli / Staphylococcus aureus), the antibacterial persistence is tested according to JIS Z 2801 (after 50 washes), and the dynamic friction coefficient is tested according to DIN 51131. The test results are shown in the following table:

[0061]

[0062]

[0063] As can be seen from the above embodiments, by comparing Examples 1-3 with Comparative Example 2, it can be known that through the ultraviolet cross-linking effect between the antibacterial agent obtained by loading silver nanoparticles on microspheres and the thermoplastic elastomer, the antibacterial property and wash resistance of the PVC foam pad can be significantly improved, thereby achieving the effect of long-term antibacterial and bacteriostatic. From Comparative Example 3, it can be seen that the compatibility between the unmodified polycarbonate and each component and the PVC resin matrix is poor, resulting in a significant decrease in the tensile strength. This shows that the elastic network formed between the thermoplastic elastomer prepared in the present invention and the plasticizer and PVC has a good toughening and plasticizing effect on the PVC foam pad. From Comparative Examples 1 and 4, it can be seen that through the combined action of introducing a hydrophobic and oleophobic modified cellulose-based aerogel, a foaming agent and a gradient pressure reduction foaming process, it is beneficial to improve the pore uniformity and low surface energy characteristics of the PVC foam pad, thereby endowing the PVC foam pad with good air permeability.

[0064] The above specific embodiments further illustrate the technical solutions and beneficial effects of the present invention, rather than limiting the implementation manner. For those skilled in the art, any obvious substitution without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. A breathable and antibacterial PVC foam pad, characterized by: The invention comprises the following raw materials in parts by weight: 90-100 parts of PVC resin, 10-30 parts of plasticizer, 3-6 parts of heat stabilizer, 5-10 parts of foaming agent, 10-20 parts of air-permeable filler, 1-6 parts of antibacterial agent, 5-15 parts of thermoplastic elastomer and 1-3 parts of lubricant.

2. The breathable and antibacterial PVC foam pad according to claim 1, characterized in that: The plasticizer is at least one of dioctyl terephthalate, polybutylene adipate, polyhexylene adipate, and epoxidized soybean oil.

3. The breathable and antibacterial PVC foam pad according to claim 1, characterized in that: The heat stabilizer is at least one of magnesium aluminum hydrotalcite, lanthanum stearate, calcium stearate, zinc stearate, epoxy soybean oil, and phosphite.

4. The breathable and antibacterial PVC foam pad according to claim 1, characterized in that: The foaming agent is at least one of azodicarbonamide, azobisisobutyronitrile, p-toluenesulfonyl hydrazide, and / or at least one of nano zinc oxide, citric acid, sodium bicarbonate, and polycarboxylic acid foaming agents.

5. The breathable and antibacterial PVC foam pad according to claim 1, characterized in that: The air permeable filler is a hydrophobic and oleophobic modified cellulose-based aerogel.

6. The breathable and antibacterial PVC foam pad according to claim 1, characterized in that: The antibacterial agent is a microsphere-loaded nanosilver antibacterial agent.

7. The breathable and antibacterial PVC foam pad according to claim 1, characterized in that: The thermoplastic elastomer is a polycarbonate containing a cinnamate group in the side chain.

8. The breathable and antibacterial PVC foam pad according to claim 1, characterized in that: The lubricant is at least one of stearic acid, calcium stearate, glycerol monostearate, polyethylene wax, oxidized polyethylene wax, and ethylene bisstearamide.

9. The method for preparing the breathable and antibacterial PVC foam pad according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step S1, drying the air-permeable filler in a vacuum oven for 2-4 hours, then placing it in an ethanol solution containing a silane coupling agent and ultrasonicating it for 10-30 minutes, and drying it for later use; Step S2, premixing the thermoplastic elastomer and a small amount of plasticizer, and swelling them at 80-90° C. for 1-3 hours for standby use; Step S3, adding the PVC resin and the remaining plasticizer into an internal mixer, controlling the temperature to 120-130° C. for premixing for 5-10 minutes, then adding a heat stabilizer and a lubricant, raising the temperature to 130-140° C. for high-speed mixing for 3-6 minutes, then adding the breathable filler treated in step S1, the thermoplastic elastomer treated in step S2, and the antibacterial agent, raising the temperature to 150-160° C. for high-speed mixing for 5-8 minutes under nitrogen protection, so that the mixture is fully mixed; Step S4, putting the mixed material obtained in step S3 into a twin-screw extruder for extrusion molding, with four zones in total, wherein a foaming agent is injected into three zones, gradient decompression foaming is performed in the fourth zone, and then cooling, shaping, pulling and cutting are performed to obtain a primary PVC foam pad; Step S5, irradiate the primary PVC foam pad obtained in step S4 under ultraviolet light for 10-15 minutes, then transfer to a 78-82° C. hot air oven for treatment for 1-2 hours, and finally place it at room temperature for 20-24 hours to obtain the finished PVC foam pad.

10. The method for preparing the breathable and antibacterial PVC foam pad according to claim 9, characterized in that: In step S4, the temperature of each section of the extruder is set to: 140-155°C in zone 1, 155-170°C in zone 2, 170-185°C in zone 3, and 180-200°C in zone 4. In zone 4, the head pressure is reduced from 10-15MPa to 5MPa for gradient pressure reduction foaming.

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