Acid-base color developing adsorption cotton and preparation method thereof

Abstract

The invention provides acid-base developing adsorption cotton and a preparation method thereof, and relates to the field of chemical emergency adsorption materials. Comprising a substrate and a color developing layer, the color developing layer comprises polyvinyl alcohol and at least one acid-base indicator. The preparation method comprises the following steps: adding partially hydrolyzed polyvinyl alcohol into distilled water, stirring until the partially hydrolyzed polyvinyl alcohol is completely dissolved, then cooling, and adding glycerol; an acid-base indicator is added into ethyl alcohol, then an acid-base regulator is added, and the pH value is adjusted to be within a preset range; mixing the color developing agent solution with the PVA solution, and uniformly stirring to obtain a color developing spraying solution; uniformly spraying a silane coupling agent ethanol solution on the surface of the adsorption cotton, and drying; spraying the color developing spraying liquid on the surface of a base material, and drying to obtain the acid-base color developing adsorption cotton. The acid-base indicator is loaded on the adsorption carrier by utilizing the film-forming property of polyvinyl alcohol, so that the dual effects of adsorption and color development can be realized. The problems that an existing polypropylene acid absorption material does not have a color development function and is poor in operation safety are solved.

Description

Technical Field

[0001] This invention relates to the field of chemical emergency adsorption materials, and more specifically, to an acid-base colorimetric adsorption cotton and its preparation method. Background Technology

[0002] Currently, the acid-absorbing cotton commonly used in the industrial field is mostly non-woven absorbent material made of polypropylene meltblown. Although it has good adsorption performance, it cannot identify the absorbed chemicals in real time. Especially in acid and alkali leak emergencies, operators need to use pH test paper or instruments for detection, which not only increases the complexity of use, but also has problems such as response delay and high safety risks. Summary of the Invention

[0003] The purpose of this invention is to provide an acid-base color-developing absorbent cotton to solve the problems of existing polypropylene acid-absorbing materials lacking color-developing function and having poor operational safety.

[0004] Another objective of this invention is to provide a method for preparing acid-base color-developing adsorbent cotton, which utilizes the film-forming properties of polyvinyl alcohol to load acid-base indicators onto an adsorbent carrier, thereby achieving both adsorption and color development effects.

[0005] The technical problem solved by this invention is achieved by the following technical solution.

[0006] On one hand, embodiments of the present invention provide an acid-base color-developing absorbent cotton, comprising a substrate with adsorption properties and a color-developing layer loaded on the substrate; the color-developing layer comprises polyvinyl alcohol and at least one acid-base indicator.

[0007] In some embodiments of the present invention, the acid-base indicator is one or more of phenolphthalein, bromophenol blue, and thymol blue.

[0008] In some embodiments of the present invention, the color developing layer further includes one or more of glycerol, antioxidants, ultraviolet stabilizers, and pH adjusters.

[0009] In some embodiments of the present invention, the polyvinyl alcohol has a mass-volume concentration of 2-3%, and the volume-to-mass ratio of the polyvinyl alcohol to the acid-base indicator is 50:1.

[0010] In some embodiments of the present invention, the substrate is polypropylene acid-absorbing cotton.

[0011] Another object of the present invention is to provide a method for preparing acid-base colorimetric adsorption cotton, comprising the following steps:

[0012] S1, Preparation of PVA solution: Partially hydrolyzed polyvinyl alcohol is added to distilled water and stirred at 80-90℃ until completely dissolved; then it is taken out and cooled to 40-45℃, then glycerol is added and stirred and mixed to obtain PVA solution;

[0013] S2, Preparation of colorimetric reagent solution: Add acid-base indicator to ethanol, stir until completely dissolved, then add acid-base adjuster to adjust pH to the preset range;

[0014] S3. Preparation of color-developing spray solution: Mix the color developer solution with the PVA solution and stir evenly to obtain the color-developing spray solution;

[0015] S4. Pretreatment of adsorption cotton: Spray the silane coupling agent ethanol solution evenly onto the surface of the adsorption cotton and dry it;

[0016] S5. Spraying: Spray the color-developing spray liquid onto the surface of the substrate and dry it to obtain the acid and alkali color-developing absorbent cotton.

[0017] In some embodiments of the present invention, in steps S4 and S5, the drying temperature is 50-60°C and the drying time is 10-30 min.

[0018] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects:

[0019] The acid-base indicator absorbent cotton provided by this invention has the advantages of instant response and safe operation: it does not require the use of external test strips or pH instruments, and is intuitive and safe to use.

[0020] Furthermore, 1. The color is stable when not in use: pH pre-adjustment effectively prevents premature color development due to air humidity or residual alkali;

[0021] 2. The absorbent cotton has strong surface adhesion and good flexibility: Through the optimization of coupling agent + glycerin, the adhesion and anti-peeling properties of the color development layer are improved, and the bonding strength between the acid and alkali indicator and the substrate is high.

[0022] 3. The color-developing layer and color-developing spray liquid provided by the present invention are compatible with the existing PP cotton preparation system, can be film-formed using conventional spraying processes, and are compatible with industrial production equipment;

[0023] 4. Wide range of applications: Suitable for leakage monitoring and emergency adsorption applications in chemical plants, clean rooms, semiconductor workshops, laboratories, airports, high-speed railways, nuclear power plants, and other fields. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1The absorbent cotton prepared in Example 1 of this invention;

[0026] Figure 2 This is a picture of the absorbent cotton after absorbing alkaline solution in Example 1 of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to specific embodiments.

[0029] This invention provides an acid-base color-developing absorbent cotton, comprising an adsorption substrate and a color-developing layer loaded on the substrate; the color-developing layer comprises polyvinyl alcohol and at least one acid-base indicator. The acid-base indicator is one or more of phenolphthalein, bromophenol blue, and thymol blue.

[0030] These include, but are not limited to, the following color development systems:

[0031] Colorimetric System 1: The combination of phenolphthalein and bromophenol blue, the formulation of which is shown in the table below:

[0032] Element Dosage Remark Bromophenol blue 0.05g Acidic color developer, changes color to yellow Phenolphthalein 0.05g Alkaline color developer, changes color to pink ethanol 150mL Dissolving bromophenol blue and phenolphthalein distilled water 50mL Adjusting solution concentration and dissolving other components Citric acid 0.01g Adjust the pH to 4.8.

[0033] The preparation steps for the colorimetric reagent solution of this formula are as follows:

[0034] 1. Dissolve the colorimetric reagent: Dissolve 0.05g bromophenol blue and 0.05g phenolphthalein separately in 150mL ethanol;

[0035] 2. pH adjustment: Add citric acid (0.01g) and use a pH meter to check the pH value of the solution until the pH value is adjusted to 4.8;

[0036] 3. Dilute the solution: Add 50mL of distilled water to make a final volume of 200mL, ensuring the solution is homogeneous.

[0037] Pre-adjusted pH: 4.8. This solution remains colorless or pale yellow under normal conditions, turns yellow when in contact with acidic substances, and turns pink when in contact with alkaline substances.

[0038] Colorimetric System 2: Bromothymol Blue and Phenolphthalein combination system, the formula is as follows:

[0039] Element Dosage Remark Bromothymol Blue 0.05g Acidic color developer, changes color to yellow Phenolphthalein 0.05g Alkaline color developer, changes color to pink ethanol 100mL Dissolving bromothymol blue and phenolphthalein distilled water 100mL Adjusting solution concentration and dissolving other components Sodium acetate 0.01g Adjust the pH to 5.2.

[0040] The preparation steps of the colorimetric reagent solution for this colorimetric formulation are as follows:

[0041] 1. Dissolve the colorimetric reagent: Dissolve 0.05g of bromothymol blue and 0.05g of phenolphthalein in 100mL of ethanol respectively;

[0042] 2. pH adjustment: Add sodium acetate (0.01g) and use a pH meter to check the pH value of the solution, and adjust it to 5.2;

[0043] 3. Dilute the solution: Add 100mL of distilled water to make a final volume of 200mL.

[0044] Pre-adjusted pH: 5.2. This solution is yellow or colorless under normal storage conditions, turns yellow when in contact with acidic substances, and turns pink when in contact with alkaline substances.

[0045] Colorimetric System 1 (phenolphthalein and bromophenol blue): pH 4.8, colorless or pale yellow under normal storage, yellow under acidic conditions, and pink under alkaline conditions; Colorimetric System 2 (bromothymol blue and phenolphthalein): pH 5.2, colorless or yellow under normal storage, yellow under acidic conditions, and pink under alkaline conditions.

[0046] The color-developing layer also includes one or more of glycerol, antioxidants, UV stabilizers, and pH adjusters. The concentration of the glycerol aqueous solution is 1% (w / v), and the amount of glycerol aqueous solution added is 5-6% of the volume of the PVA solution. Adding glycerol to the color-developing solution helps to improve the flexibility and workability of the film after formation.

[0047] In this invention, the roles of each substance are as follows: Partially hydrolyzed polyvinyl alcohol (PVA): serves as a carrier for the color developer, providing good film-forming properties and adhesion; Glycerin: acts as a softener, improving the flexibility and feel of the coating and preventing film embrittlement; Acid-base indicators (such as bromophenol blue, phenolphthalein, etc.): provide a color reaction and sense acid-base changes; Coupling agent (KH-550): used to treat the polypropylene surface, enhancing the adhesion between PVA and PP surfaces; Trace amounts of acidity regulator (citric acid): used to adjust the pH value, ensuring that the color developer does not develop color under normal storage conditions until it comes into contact with acidic or alkaline liquids; Antioxidant (BHT) and UV stabilizer (BP-1) are used to improve the long-term stability of the coating, especially in outdoor environments or during long-term storage.

[0048] The polyvinyl alcohol has a volume concentration of 2-3%, and the volume ratio of polyvinyl alcohol to the color developer is 50:1. More preferably, the volume ratio of PVA:glycerol is 2.5:0.1 (w / v); the volume ratio of PVA:color developer (bromophenol blue, phenolphthalein) is 50:1 (w / v).

[0049] In some embodiments of the present invention, the substrate is polypropylene acid-absorbing cotton, or it can be a composite material of sulfonated polyvinyl alcohol (PVA) and microcrystalline cellulose (MCC).

[0050] The preparation method of the acid-base colorimetric adsorption cotton according to an embodiment of the present invention includes the following steps:

[0051] S1, Preparation of PVA solution: Partially hydrolyzed polyvinyl alcohol is added to distilled water and stirred at 80-90℃ until completely dissolved; then it is taken out and cooled to 40-45℃, then glycerol is added and stirred and mixed to obtain PVA solution;

[0052] S2, Preparation of colorimetric reagent solution: Add acid-base indicator to ethanol, stir until completely dissolved, then add acid-base adjuster to adjust pH to the preset range;

[0053] S3, Preparation of color-developing spray solution: Mix the color-developing agent solution with the PVA solution and stir evenly to obtain the color-developing spray solution;

[0054] S4, Pretreatment of adsorption cotton: Spray the silane coupling agent ethanol solution evenly onto the surface of the adsorption cotton and dry it;

[0055] S5, Spraying: Spray the color-developing spray liquid onto the surface of the substrate and dry it to obtain the acid and alkali color-developing absorbent cotton.

[0056] In some embodiments of the present invention, in steps S4 and S5, the drying temperature is 50-60°C and the drying time is 10-30 min.

[0057] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0058] Example 1

[0059] The polypropylene absorbent cotton with a low-concentration color-developing coating of this embodiment is prepared according to the following steps:

[0060] 1. Preparation of PVA solution: Take 5g of partially hydrolyzed polyvinyl alcohol (PVA, molecular weight 44000, degree of hydrolysis 87%) and add it to 200mL of distilled water; stir at 80℃ until completely dissolved; remove and cool to 40℃, add 5mL of glycerol aqueous solution (concentration 1%), and continue stirring to mix to obtain PVA solution.

[0061] 2. Preparation of colorimetric reagent solution: Add 0.05g bromophenol blue and 0.05g phenolphthalein to 150mL ethanol respectively; stir until completely dissolved, and then adjust the pH to 4.8 with citric acid.

[0062] 3. Preparation of color-developing spray solution: Mix 150 mL of color developer solution with 200 mL of PVA solution and stir evenly to obtain the color-developing spray solution.

[0063] 4. Coupling agent treatment of polypropylene acid-absorbing cotton: Dissolve 2 mL of KH-550 coupling agent solution (concentration 2%) in 98 mL of ethanol and spray it evenly on the surface of polypropylene acid-absorbing cotton; put the sprayed cotton sample into a 60℃ oven to dry for 10 minutes.

[0064] 5. Spraying and drying the color-developing liquid: Use a spray gun to evenly spray the color-developing liquid onto the surface of the polypropylene acid-absorbing cotton; after spraying, place it in a 60℃ oven to dry for 30 minutes. Once completely dry, the absorbent cotton is obtained.

[0065] The absorbent cotton in this embodiment has a colorless or light yellow surface, a soft touch, and is not easily detached.

[0066] Performance testing:

[0067]

[0068] Example 2

[0069] The polypropylene absorbent cotton for the high-concentration colorimetric layer of this embodiment is prepared according to the following steps:

[0070] 1. Preparation of PVA solution: Take 7g of partially hydrolyzed PVA (PVA, molecular weight 67000, degree of hydrolysis 88%) and add it to 200mL of distilled water; stir until completely dissolved, and keep the temperature at 90℃; take it out and cool it to 40℃, add 7mL of glycerol aqueous solution (concentration 1%), and stir evenly.

[0071] 2. Preparation of colorimetric reagent solution: Dissolve 0.1g bromophenol blue and 0.1g phenolphthalein in 200mL ethanol; adjust pH to 5.2 and stir until completely dissolved.

[0072] 3. Preparation of color-developing spray solution: Mix the color developer solution and PVA solution in a certain proportion to obtain the color-developing spray solution.

[0073] 4. Coupling agent treatment of polypropylene acid-absorbing cotton: Spray 2% KH-550 coupling agent solution evenly onto the surface of PP acid-absorbing cotton; dry at 60℃ for 10 minutes.

[0074] 5. Spray the color developer and dry: Use a spray gun to evenly spray the color developer onto the surface of the acid-absorbing cotton; place it in a 60℃ oven to dry for 30 minutes.

[0075] Performance testing:

[0076]

[0077] Example 3

[0078] The polypropylene absorbent cotton with a medium-concentration color-developing coating of this embodiment is prepared according to the following steps:

[0079] 1. Preparation of PVA solution: Dissolve 6g of partially hydrolyzed PVA (PVA, molecular weight 55000, degree of hydrolysis 87%) in 200mL of distilled water; stir at 85℃ until completely dissolved; remove and cool to 40℃, add 6mL of glycerol aqueous solution (concentration 1%) and stir evenly.

[0080] 2. Preparation of colorimetric reagent solution: Dissolve 0.075g bromophenol blue and 0.075g phenolphthalein in 180mL ethanol; adjust the pH to 5.0 with citric acid and stir well.

[0081] 3. Preparation of color-developing spray solution: The color-developing agent solution is mixed with the PVA solution to obtain the color-developing spray solution.

[0082] 4. Coupling agent treatment of polypropylene acid-absorbing cotton: Spray 2% KH-550 coupling agent solution onto the PP surface; dry at 60℃ for 10 minutes.

[0083] 5. Spray the color developer and dry: Spray the color developer evenly onto the surface of the polypropylene acid-absorbing cotton; place it in a 60℃ oven to dry for 30 minutes.

[0084] Performance testing:

[0085]

[0086] From the performance data of Examples 1-3 above, it can be concluded that the absorbent cotton of the present invention exhibits superior performance in terms of color development, response time, and storage stability: stable color development, no color change when not in contact with acids or alkalis; rapid color development response, instantaneous color development upon contact with acids or alkalis; and stable color under normal storage conditions, requiring no special storage conditions.

[0087] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. An acid-base color-changing absorbent cotton, characterized in that, It includes a substrate with adsorption properties and a color-developing layer loaded on the substrate; the color-developing layer includes polyvinyl alcohol and at least one acid-base indicator.

2. The acid-base color-developing absorbent cotton according to claim 1, characterized in that, The acid-base indicator is one or more of phenolphthalein, bromophenol blue, and thymol blue.

3. The acid-base color-developing absorbent cotton according to claim 1, characterized in that, The color development layer also includes one or more of glycerol, antioxidants, UV stabilizers, and pH adjusters.

4. The acid-base color-developing absorbent cotton according to claim 1, characterized in that, The polyvinyl alcohol has a mass-volume concentration of 2-3%, and the volume-mass ratio of the polyvinyl alcohol to the acid-base indicator is 50:

1.

5. The acid-base color-developing absorbent cotton according to claim 1, characterized in that, The substrate is one of polypropylene acid-absorbing cotton or sulfonated polyvinyl alcohol-microcrystalline cellulose composite material.

6. A method for preparing acid-base colorimetric adsorption cotton as described in any one of claims 1-5, characterized in that, Includes the following steps: S1, Preparation of PVA solution: Partially hydrolyzed polyvinyl alcohol is added to distilled water and stirred at 80-90℃ until completely dissolved; then it is taken out and cooled to 40-45℃, then glycerol is added and stirred and mixed to obtain PVA solution; S2, Preparation of colorimetric reagent solution: Add acid-base indicator to ethanol, stir until completely dissolved, then add acid-base adjuster to adjust pH to the preset range; S3, Preparation of color-developing spray solution: Mix the color-developing agent solution with the PVA solution and stir evenly to obtain the color-developing spray solution; S4, Pretreatment of adsorption cotton: Spray the silane coupling agent ethanol solution evenly onto the surface of the adsorption cotton and dry it; S5, Spraying: Spray the color-developing spray liquid onto the surface of the substrate and dry it to obtain the acid and alkali color-developing absorbent cotton.

7. The method for preparing acid-base colorimetric adsorption cotton according to claim 6, characterized in that, In steps S4 and S5, the drying temperature is 50-60℃ and the drying time is 10-30 min.

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