Hydrophobic odor-eliminating silica particles and method for preparing hydrophobic odor-eliminating silica

Abstract

The present application relates to the field of sanitary materials, and provides a preparation method of hydrophobic deodorant silicon dioxide, which solves the defects that the silicon dioxide in the prior art is difficult to disperse in a hydrophobic base material and does not have deodorant performance. The method comprises the following preparation steps: (1) preparing raw materials: taking fumed silicon dioxide as the raw material; (2) adding an alkylating agent to the fumed silicon dioxide in step (1), wherein the mass ratio of the alkylating agent to the fumed silicon dioxide is 5-20:100, the reaction time is 0.5-2 h, and the reaction temperature is controlled at 150-200 DEG C, to obtain hydrophobic silicon dioxide; (3) adding ethanol and a deodorant solution to the hydrophobic silicon dioxide in step (2) at room temperature, stirring for 1-4 h, drying, and filtering to obtain hydrophobic deodorant silicon dioxide.

Description

Technical Field

[0001] The present invention relates to the field of sanitary materials, and in particular to a method for preparing hydrophobic and deodorizing silica. Background Art

[0002] Porous silica particles have a wide range of applications in the chemical, environmental, and medical fields due to their low density, high specific surface area, biocompatibility, and non-toxicity. They are particularly useful in the manufacture of lightweight, deodorizing, breathable membranes. However, they contain a large number of hydroxyl groups and are highly hydrophilic, making them difficult to evenly disperse in hydrophobic substrates such as polyethylene. Furthermore, their lack of deodorizing properties limits their further applications. Therefore, modifying silica to make it hydrophobic and deodorizing, and developing hydrophobic and deodorizing silica, is of great practical significance.

[0003] Although there are some reports on hydrophobic materials and deodorizing materials, there are no reports on combining the two to prepare silica particles with both hydrophobic and deodorizing properties. For example, Chinese Patent No. 201680004464.7 discloses a method for preparing a hydrophobic silica aerogel and the hydrophobic silica aerogel prepared thereby, the method comprising the following steps: (1) preparing a water glass dispersion; (2) adding the water glass dispersion and a surface modifier solution to a reactor and simultaneously performing surface modification, gelation, and solvent replacement to prepare a hydrophobic silica wet gel; and (3) drying the hydrophobic silica wet gel, wherein the method further comprises adding ammonium hydroxide during the reaction of step (2), wherein the water glass dispersion comprises a water glass solution and an inorganic acid, wherein after adding the entire amount of the surface modifier solution, ammonium hydroxide is added when the pH in the reactor reaches 5 to 10, and wherein the amount of ammonium hydroxide added is such that the molar ratio of the ammonium hydroxide to the surface modifier in the surface modifier solution is in the range of 0.5 to 25. This silica has hydrophobic properties but does not have deodorizing properties.

[0004] For example, Chinese Patent No. 202010618202.8 discloses a method for surface modification of silica, comprising: cleaning the surface of a silica sample; heating the silica sample at 490°C to 510°C for 30 to 35 minutes; hydroxylating the silica sample surface; placing the silica sample in an electrolytic cell containing a 0.025% to 0.030% calcium chloride or magnesium chloride solution; and applying a 1.5V / cm to 1.7V / cm direct current to electrically stimulate the silica surface, thereby cleaving Si-O-Si bonds and reacting with H+ and OH- in water; and alkylating the silica sample; placing the electrically hydroxylated silica sample in a reaction solution of a novel silane coupling agent (preferred ratio: KH560:benzene:methanol = 1:(9-11):(0.5-0.7) to complete the alkylation reaction and obtain a surface-modified silica sample. After the silica sample is modified using the silica surface modification method provided by the present invention, the wetting angle of deionized water on the surface of the silica sample is significantly increased, and the hydrophobicity of the silica sample surface is greatly improved. However, the silica obtained using the modification method of the present invention does not have a deodorizing function.

[0005] The challenge lies in developing silica particles with a hydrophobic surface and a hydrophilic interior. If the silica is too hydrophobic, and its pores are also hydrophobic, it will significantly affect the loading of the deodorant. Therefore, in the field of breathable membranes, developing silica particles with a hydrophobic surface that provides a certain degree of compatibility with the polyethylene matrix, while also allowing the hydrophilic particles' internal pores to load the deodorant, resulting in excellent deodorizing properties, is of great practical significance. Summary of the Invention

[0006] Therefore, in order to solve the above problems, the present invention provides a method for preparing hydrophobic deodorizing silica, which solves the defects of the prior art silica that is difficult to disperse in a hydrophobic substrate and has no deodorizing performance.

[0007] To achieve the above object, the present invention adopts the following technical solution: a method for preparing hydrophobic deodorizing silica, comprising the following preparation steps:

[0008] (1) Prepare raw materials: Use fumed silica as raw material;

[0009] (2) adding an alkylating agent to the fumed silica described in step (1) at a mass ratio of 5-20:100, reacting for 0.5-2 hours at a reaction temperature of 150-200° C. to obtain hydrophobic silica;

[0010] (3) Adding ethanol and the deodorant solution to the hydrophobic silica in step (2) at room temperature, stirring for 1-4 hours, drying, and filtering to obtain hydrophobic deodorizing silica.

[0011] Furthermore: the fumed silica used in step (1) is nano-scale.

[0012] Furthermore, the alkylating agent in step (2) is any one of hexamethyldisilazane, trimethoxyoctadecylsilane, dimethyldichlorosilane, and trimethylchlorosilane.

[0013] Furthermore: the deodorant described in step (3) is a plant deodorant containing any one of arginine, glycine, alanine, and amino acid cations, and the solid content of the deodorant is 30-35wt%.

[0014] Furthermore: the mass ratio of the deodorant solution, ethanol and hydrophobic silica in step (3) is 1-5:1:1.

[0015] A hydrophobic deodorizing silica particle is prepared by the above-mentioned method for preparing the hydrophobic deodorizing silica.

[0016] By adopting the above technical solution, the beneficial effects of the present invention are:

[0017] 1. The present invention controls the amount of alkylating agent used to modify the porous silica particles to have a hydrophobic surface and hydrophilic internal pores, and then loads a deodorant inside the pores of the particles, resulting in the prepared silica particles having hydrophobic and deodorizing properties.

[0018] 2. The present invention utilizes an alkylating agent to react with hydroxyl groups on the silica surface. By controlling the degree of alkylation, the resulting silica particles are hydrophobic on the surface and hydrophilic in the internal pores. Hydrogen bonding between functional groups such as carboxyl and amino groups of the plant deodorant and the hydroxyl groups in the internal pores of the porous silica particles allows the plant deodorant to be loaded into the hydrophilic internal pores of the porous silica particles, imparting deodorizing properties to the hydrophobic silica particles. Such materials can be used in the manufacture of lightweight, deodorizing, breathable membranes for applications such as sanitary materials.

[0019] 3. The mechanism of surface modification of silica is based on the fact that the silanol groups on its surface can react with organic silanes, alcohols and other substances. The Si(CH3)3 group in the alkylating agent reacts with the OH group on the SiO2 surface, so that the highly active Si(CH3)3 on the alkylating agent is bonded to the surface of SiO2, thereby achieving hydrophobic modification of the nano-SiO2 surface. The reaction equation for the reaction between the silanol groups on the SiO2 surface and the alkylating agent is:

[0020]

[0021] The plant deodorant molecules enter the pores of the porous alkylated silica particles. The functional groups such as carboxyl, amino, and hydroxyl groups in the plant deodorant interact with the hydroxyl groups inside the alkylated silica particles through hydrogen bonds and are adsorbed on the internal surface of the pores of the alkylated silica particles.

[0022] 4. The present invention controls the mass ratio of the alkylating agent to the fumed silica and the reaction time so that the hydrophobic groups preferentially occupy the surface of the silica particles. The mass ratio of the alkylating agent to the fumed silica is controlled within a range of 5-20:100, which makes the surface of the silica particles hydrophobic and the internal pores hydrophilic. The deodorant is added after the alkylation is completed. Since the silica particles have a porous structure, their internal pores are connected to the outside, so the deodorant can enter the interior. Since the external pores are pre-occupied by hydrophobic groups, there is no deodorant in the external pores, and the deodorant can be smoothly distributed in the internal channels of the silica particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 :(a)Water drop contact angle diagram of alkylated silica particles,(b)Water drop contact angle diagram of deodorizing loaded alkylated silica particles;

[0024] Figure 2 This is a high-resolution TEM image and EDS spectrum of alkylated silica particles;

[0025] Figure 3 This is a high-resolution TEM photo and EDS spectrum of deodorizing alkylated silica particles. DETAILED DESCRIPTION

[0026] The method of the present invention is further described in detail below with reference to the examples. It should be noted that the scope of protection of the present invention should include but not be limited to the technical content disclosed in the examples. Example 1

[0027] A method for preparing hydrophobic deodorizing silica comprises the following steps:

[0028] (1) Add 12 mL of hexamethyldisilazane to 100 g of porous silica particles and react at 180°C for 30 min to obtain hexamethyldisilazane-modified silica particles;

[0029] (2) 100 g of hexamethyldisilazane-modified silica particles and 100 g of ethanol were added to 100 mL of a plant deodorant solution containing arginine with a solid content of 30 wt.%, stirred for 1 h, filtered, washed, and dried to obtain hydrophobic deodorizing silica particles. Example 2

[0030] A method for preparing a hydrophobic odor-eliminating silica, comprising the following preparation steps:

[0031] (1) 20 mL trimethoxyoctadecylsilane was added to 100 g porous silica particles, and reacted at 200°C for 30 min to obtain trimethoxyoctadecylsilane-modified silica particles.

[0032] (2) 100 g of the trimethoxyoctadecylsilane-modified silica particles and 100 g of ethanol were added to 500 mL of a glycine-containing plant odor-eliminating agent solution with a solid content of 30 wt.%, stirred for 1 h, filtered, washed, and dried to obtain hydrophobic odor-eliminating silica particles. Example Three

[0033] A method for preparing a hydrophobic odor-eliminating silica, comprising the following preparation steps:

[0034] (1) 8 mL dimethyldichlorosilane was added to 100 g porous silica particles, and reacted at 150°C for 30 min to obtain hexamethyldisilazane-modified silica particles.

[0035] (2) 100 g of the dimethyldichlorosilane-modified silica particles and 100 g of ethanol were added to 300 mL of an alanine-containing plant odor-eliminating agent solution with a solid content of 30 wt.%, stirred for 1 h, filtered, washed, and dried to obtain hydrophobic odor-eliminating silica particles. Example Four

[0036] A method for preparing a hydrophobic odor-eliminating silica, comprising the following preparation steps:

[0037] (1) 15 mL trimethylchlorosilane was added to 100 g porous silica particles, and reacted at 185°C for 30 min to obtain trimethylchlorosilane-modified silica particles.

[0038] (2) 100 g of the trimethylchlorosilane-modified silica particles and 100 g of ethanol were added to 200 mL of an arginine-containing plant odor-eliminating agent solution with a solid content of 30 wt.%, stirred for 1 h, filtered, washed, and dried to obtain hydrophobic odor-eliminating silica particles.

[0039] Main performance test

[0040] The hydrophobic odor-eliminating silica particles prepared by the present application have the important characteristics of both hydrophobicity and odor-eliminating performance, and therefore the hydrophobicity and odor-eliminating performance thereof were tested.

[0041] Reference Figures 1 to 3The modified deodorizing silica particles in all examples have hydrophobic and deodorizing properties. The hydrophobic silica particles and the hydrophobic deodorizing silica particles were respectively attached to a glass plate for water drop shape analysis. Figure 1 Pure silica particles are highly hydrophilic. A water droplet falling on the particle surface is immediately absorbed by the particle, exhibiting a contact angle of 0°. The contact angle of hydrophobically modified silica particles is 139.5°, indicating strong hydrophobicity. Furthermore, the contact angle of hydrophobic, deodorizing silica particles, which have undergone further deodorizing treatment, is 134.2°, indicating that the deodorizing particles remain highly hydrophobic and that deodorant treatment has little effect on their hydrophobicity.

[0042] The deodorizing performance of hydrophobic deodorizing silica particles was analyzed using a detector tube according to the method specified in GB / T 33610.2-2017. The particles reduced ammonia concentration by 98.8%, demonstrating excellent deodorizing effectiveness. This material can be used in the manufacture of breathable membranes in the medical field. Example 5

[0043] A composition for a lightweight, breathable base film for sanitary products, comprising the following raw materials in parts by weight: 5 parts by weight of the hydrophobic deodorizing silica of Example 1, 3 parts of an antibacterial agent, and 100 parts by weight of a polyolefin resin, wherein the hydrophobic deodorizing silica is prepared by modifying silica with an alkylating agent, a deodorizing agent, and an antibacterial agent, wherein the deodorizing agent is a plant-based deodorant containing 30 wt% arginine, and the antibacterial agent is chitosan.

[0044] The hydrophobic deodorizing silica is prepared by the following steps: (1) preparing raw materials: using fumed silica as raw material; (2) adding hexamethyldisilazane to the fumed silica described in step (1), wherein the mass ratio of hexamethyldisilazane to the fumed silica is 5:100, reacting for 0.5 h, and controlling the reaction temperature at 150° C. to obtain hydrophobic silica; (3) adding ethanol, a plant deodorant containing arginine with a solid content of 30 wt% and chitosan to the hydrophobic silica in step (2) at room temperature, stirring for 1 h, centrifugally filtering and drying, and controlling the moisture content within 400 ppm to obtain hydrophobic deodorizing silica.

[0045] The mass ratio of the arginine, chitosan, ethanol and hydrophobic silica is 0.2:0.1:50:20.

[0046] The silica particle size is 18 nm, the average adsorption pore size is 0.24 nm, and the specific surface area is 215 m 2 / g. Example 6

[0047] A method for preparing a lightweight, deodorizing, and breathable base film for sanitary products, comprising the following preparation steps: (1) mixing the composition of the lightweight, breathable base film for sanitary products of Example 5 with a processing aid, wherein the processing aid is specifically nano-titanium dioxide, calcium carbonate, a titanate coupling agent, and polyethylene wax, and the amount of the processing aid is 2 wt% of the polyolefin resin, that is, the processing aid is 2 parts by weight, more specifically, 0.5 parts by weight of titanium dioxide, 0.6 parts by weight of calcium carbonate, 0.4 parts by weight of a titanate coupling agent, and 0.5 parts by weight of polyethylene wax, and stirring evenly to obtain a mixture; (2) feeding the mixture into a screw extruder, and subjecting it to melt extrusion and cooling; (3) subjecting it to four-stage stretching through a stretching mechanism, with stretching ratios of 1.3, 1.5, 1.7, and 1.6, respectively; and (4) further subjecting it to shaping and cooling to prepare a lightweight, deodorizing, and breathable base film. Example 7

[0048] A deodorizing disposable sanitary product comprises a liquid-permeable surface layer, an absorbent body, and a liquid-impermeable bottom layer stacked in sequence from top to bottom. The absorbent body is formed by mixing a deodorizing material, fluff pulp, and a high-molecular-weight water-absorbing resin in a weight ratio of 1:20:2. The liquid-impermeable bottom layer is formed by a hydrophobic deodorizing breathable membrane and a hydrophobic non-woven fabric composited to the bottom of the hydrophobic deodorizing breathable membrane. The hydrophobic deodorizing breathable membrane is formed by 5 parts by weight of hydrophobic deodorizing silica, 100 parts by weight of a polyolefin resin, and 3 parts by weight of a processing aid. The deodorizing material is deodorizing silica loaded with an aromatic material.

[0049] The preparation method for the fragrance-loaded deodorizing silica comprises: selecting silica particles with a pore size of 10 nm as a raw material, adding a fragrance essential oil, and stirring to allow the fragrance essential oil to be fully absorbed by the silica. An acrylic water-based adhesive is then added and stirred again to obtain the fragrance-loaded deodorizing silica. The silica: fragrance essential oil: acrylic water-based adhesive ratio is 1:0.1:0.05, calculated by mass.

[0050] The solid content of the plant deodorant is 30wt%, the mass ratio of the plant deodorant, ethanol and hydrophobic silica is 0.2:50:20, the silica particle size is 18nm, the average adsorption pore size is 0.24nm, and the specific surface area is 215m 2 / g.

[0051] The preparation method of the hydrophobic deodorizing silica is prepared by adopting the preparation method of the hydrophobic deodorizing silica in Example 1. Example 8

[0052] A method for preparing a deodorizing disposable sanitary product, comprising the following preparation steps:

[0053] (1) preparing a liquid-permeable surface layer;

[0054] (2) Preparation of absorbent body: Deodorizing material, fluff pulp and high molecular water-absorbing resin are fed into the mold cavity of a mold wheel in a weight ratio of 1:200:2 for molding, and then demolded to obtain an absorbent body; the deodorizing material is deodorizing silica loaded with aromatic material, and the preparation method of the deodorizing silica loaded with aromatic material is as follows: silica particles with a pore size of 10 nm are selected as raw materials, aromatic essential oil is added, stirred so that the aromatic essential oil is fully absorbed by the silica, and then a low-temperature water-based adhesive is added and stirred evenly again to obtain the deodorizing silica loaded with aromatic material; the silica: aromatic essential oil: acrylic water-based adhesive = 1:0.1:0.05, calculated by mass ratio;

[0055] (3) Preparation of a liquid-impermeable bottom layer: unwinding a hydrophobic nonwoven fabric, transferring it online, and compounding a hydrophobic deodorizing breathable film online on its surface, wherein the preparation method of the hydrophobic deodorizing breathable film comprises the following steps: a. mixing 50 parts by weight of hydrophobic deodorizing silica, 100 parts by weight of a polyolefin resin, and 3 parts by weight of a processing aid, stirring uniformly to obtain a mixture; b. feeding the mixture into a screw extruder, melt-extruding, and cooling; c. performing four-stage stretching through a stretching mechanism, with stretching ratios of 1.3, 1.5, 1.7, and 1.6, respectively; d. finalizing the process and cooling;

[0056] The preparation method of hydrophobic deodorizing silica adopts the preparation method of Example 1;

[0057] (4) The liquid-permeable surface layer, absorbent body and liquid-impermeable bottom layer transmitted online are compounded into one body, and then cut into pieces to obtain individual deodorizing disposable sanitary products. Example 9

[0058] A deodorizing adult diaper comprises a liquid-permeable surface layer, an absorbent body, and a liquid-impermeable bottom layer stacked in sequence from top to bottom. The absorbent body comprises 10 parts by weight of a high molecular weight water-absorbing resin, 2 parts by weight of silicon dioxide, 5 parts by weight of a surfactant, 1 part by weight of an essential oil, 0.5 parts by weight of an acrylic acid aqueous adhesive, and 900 parts by weight of fluff pulp. The liquid-impermeable bottom layer comprises a hydrophobic deodorizing breathable membrane and a hydrophobic non-woven fabric composited to the bottom of the hydrophobic deodorizing breathable membrane. The hydrophobic deodorizing breathable membrane comprises 5 parts by weight of hydrophobic deodorizing silicon dioxide, 100 parts by weight of a polyolefin resin, and 3 parts by weight of a processing aid.

[0059] The preparation method of the hydrophobic deodorizing silica comprises the following steps: (1) preparing raw materials: taking fumed silica as the raw material; (2) adding hexamethyldisilazane into the fumed silica in step (1), the mass ratio of the alkylating agent to the fumed silica is 5:100, the reaction is carried out for 0.5 h, the reaction temperature is controlled at 150 DEG C, and the hydrophobic silica is obtained; (3) adding ethanol and a plant deodorant solution containing arginine into the hydrophobic silica in step (2) at normal temperature, stirring for 1 h, centrifugal filtration and drying, the moisture is controlled within 400 ppm, and the hydrophobic deodorizing silica is obtained.

[0060] The solid content of the plant deodorant is 30 wt%, the mass ratio of the plant deodorant, ethanol and hydrophobic silica is 0.2:50:20, the particle size of the silica is 18 nm, the adsorption average pore size is 0.24 nm, and the specific surface area is 215 m 2 / g.

[0061] The preparation process of the absorbent comprises the following steps: a. adding a surfactant into essential oil to emulsify the essential oil so that the essential oil is wrapped by the surfactant; b. uniformly mixing a high-molecular water-absorbing resin and silica with a pore size of 10 nm, and adding an acrylic water-based adhesive to bond the high-molecular water-absorbing resin and the silica into an integrated body; c. adding the emulsified essential oil in step a into the material in step b, uniformly mixing and stirring, and obtaining a pre-preparation; d. feeding the pre-preparation and fluff pulp into a die hole of a die wheel according to a proportion, forming, and then demolding to obtain the absorbent. Example Ten

[0062] A preparation method of a deodorizing adult paper diaper comprises the following preparation processes:

[0063] (1) preparing a liquid-permeable surface layer;

[0064] (2) preparing an absorbent: a. adding a surfactant into essential oil to emulsify the essential oil so that the essential oil is wrapped by the surfactant; b. uniformly mixing a high-molecular water-absorbing resin and silica with a pore size of 10 nm, and adding an acrylic water-based adhesive to bond the high-molecular water-absorbing resin and the silica into an integrated body; c. adding the emulsified essential oil in step a into the material in step b, uniformly mixing and stirring, and obtaining a pre-preparation; d. feeding the pre-preparation and fluff pulp into a die hole of a die wheel according to a proportion, forming, and then demolding to obtain the absorbent;

[0065] (3) Preparation of a liquid-impermeable bottom layer: unwinding a hydrophobic nonwoven fabric, transferring it online, and compounding a hydrophobic deodorizing breathable film online on its surface, wherein the preparation method of the hydrophobic deodorizing breathable film comprises the following steps: a. mixing 50 parts by weight of hydrophobic deodorizing silica, 100 parts by weight of a polyolefin resin, and 3 parts by weight of a processing aid, stirring uniformly to obtain a mixture; b. feeding the mixture into a screw extruder, melt-extruding, and cooling; c. performing four-stage stretching through a stretching mechanism, with stretching ratios of 1.3, 1.5, 1.7, and 1.6, respectively; d. finalizing the process and cooling;

[0066] The preparation method of hydrophobic deodorizing silica is as follows: a. preparing raw materials: using fumed silica as raw material; b. adding an alkylating agent to the fumed silica described in step (1), wherein the mass ratio of the alkylating agent to the fumed silica is 5-20:100, reacting for 1 hour, and controlling the reaction temperature at 150°C to obtain hydrophobic silica; c. adding ethanol and a deodorizing agent solution to the hydrophobic silica in step (2) at room temperature, stirring for 2 hours, centrifugally filtering and drying, and controlling the moisture content within 400 ppm to obtain hydrophobic deodorizing silica;

[0067] (4) The liquid-permeable surface layer, absorbent body and liquid-impermeable bottom layer transmitted online are compounded into one body, and then cut into pieces to obtain individual deodorizing disposable sanitary products.

[0068] Although the present invention has been particularly shown and described in conjunction with preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims, and all such changes are within the scope of protection of the present invention.

Claims

1. A method for preparing hydrophobic deodorizing silica, characterized in that: The method comprises the following preparation steps: (1) Prepare raw materials: Use fumed silica as raw material; (2) adding an alkylating agent to the fumed silica described in step (1) at a mass ratio of 5-20:100, reacting for 0.5-2 hours at a reaction temperature of 150-200° C. to obtain hydrophobic silica; (3) adding ethanol and the deodorant solution to the hydrophobic silica in step (2) at room temperature, stirring for 1-4 hours, drying, and filtering to obtain hydrophobic deodorizing silica; The deodorant in step (3) is a plant deodorant containing any one of arginine, glycine, alanine, and amino acid cations, and the solid content of the deodorant is 30-35 wt%; The mass ratio of the deodorant solution, ethanol and hydrophobic silica in step (3) is 1-5:1:

1.

2. The method for preparing a hydrophobic deodorizing silica according to claim 1, wherein : The fumed silica used in step (1) is nano-scale.

3. The method for preparing a hydrophobic deodorizing silica according to claim 1, wherein: The alkylating agent in step (2) is any one of hexamethyldisilazane, trimethoxyoctadecylsilane, dimethyldichlorosilane, and trimethylchlorosilane.

4. A hydrophobic deodorizing silica particle, characterized in that: The hydrophobic deodorizing silica is prepared by the preparation method of any one of claims 1 to 3.

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