Fluoride-free waterproof agent emulsion for glass fiber filter paper as well as preparation method and application of fluoride-free waterproof agent emulsion

Abstract

The invention discloses a preparation method of a high-water-resistance fluoride-free waterproof agent for glass fiber air filter paper. The preparation method comprises the following steps: reacting dihydroxyl silicone oil with isocyanate, blocking by using hydroxyl acrylic acid to prepare a hydrophobic monomer of acrylic acid blocked hydroxyl silicone oil polyurethane, and carrying out secondary polymerization on the hydrophobic monomer and other functional acrylic acid monomers to prepare the fluoride-free waterproof agent emulsion. According to the method, the ratio of the dihydroxyl silicone oil to the isocyanate is controlled, and the reserved silicon hydroxyl is combined with the silicon-oxygen bond on the glass fiber paper, so that the binding force between the fluorine-free waterproof agent and the glass fiber after the fluorine-free waterproof agent is dried to form a film can be effectively improved, and a cross-linking agent does not need to be additionally added. And cyclic acrylic acid with a high Tg value is introduced into secondary polymerization, so that the water resistance of the water-based paint can be further improved. Compared with a common waterproof agent, the glass fiber air filter paper obtained by blending, dipping and drying the fluorine-free waterproof agent emulsion prepared by the invention and an acrylic acid adhesive emulsion for glass fiber paper has more excellent water resistance, and the hydrostatic pressure resistance can reach 20kPa.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorine-free water repellent agents, and specifically relates to a fluorine-free water repellent agent emulsion for glass fiber air filter paper and a preparation method and application thereof. Background Art

[0002] Glass fiber air filter paper is made of glass fiber as the main raw material and is generally made by wet molding process. It has the characteristics of uniform fiber distribution, large dust holding capacity, small resistance, high strength, insulation, flame retardancy, etc. It is an ideal air filter material. In order to make the material have superior filtering performance, it must have excellent water resistance, strength and stiffness, and have good filtering efficiency and low resistance, which requires chemical binders and modifiers to enable it to have the above functions. It is usually mixed with a binder resin and a water repellent, especially a mixture of a water-based acrylic resin emulsion and a water-based water repellent.

[0003] To achieve high water resistance, fluorine-containing resins are generally used, such as Chinese patent CN 106861290B, which provides a fiber mesh product comprising a dendritic polymer, a waterproofing agent and a plurality of glass fibers, wherein the waterproofing agent comprises the formula -CnFmRy, wherein n is an integer less than or equal to 6, and m is an integer greater than 1, i.e., a fluorine-containing substance. It can provide a water repellency of about 1 kPa to about 20 kPa for fiber paper. Due to the restrictions of EU PFAs, the use of fluorine-containing substances is restricted to a certain extent. Chinese patent CN 116635129A provides a filter medium comprising a fluorinated water-repellent additive and a non-fluorinated water-repellent additive, and improves the water resistance of glass fiber filter paper by adding a waterproofing agent. At the same time, a non-fluorinated water-repellent is added to reduce the use of fluorine-containing substances, but it still cannot fundamentally solve the impact of fluorine-containing substances. Summary of the invention

[0004] Purpose of the invention: In view of this, the purpose of the present invention is to provide a high-efficiency fluorine-free water-repellent emulsion for glass fiber air filter paper, a preparation method thereof, and its application in the preparation of high-efficiency waterproof glass fiber air filter paper. The purpose is to provide high water resistance for glass fiber air filter paper on the basis of meeting environmental protection.

[0005] Technical solution: The fluorine-free waterproofing agent emulsion for glass fiber filter paper described in the present invention comprises the following components in parts by weight: 15-20 parts of acrylic end-capped hydroxy silicone oil polyurethane, 5-10 parts of hydrophobic monomer, 5-15 parts of cyclic monomer, 5-10 parts of cosolvent, 55-65 parts of water, 1-3 parts of composite emulsifier, and 0.1-1 part of water-soluble initiator.

[0006] Further, as a preferred embodiment, the acrylic terminated hydroxy silicone oil polyurethane is prepared by reacting dihydroxy silicone oil with isocyanate and then terminated with hydroxy acrylic acid; the structural formula is shown in formula (I):

[0007]

[0008] Wherein: the molar ratio of dihydroxy silicone oil: isocyanate: hydroxy acrylic acid is controlled to be 1:0.5-1.5:0.5-1.5; preferably 1:1:1.

[0009] Furthermore, as a preferred embodiment, the acrylic acid-terminated hydroxy silicone oil polyurethane in the reaction system accounts for 30-70% of the reaction monomer mass ratio; preferably 45-60%.

[0010] Further, as a preferred embodiment, the hydrophobic monomer is selected from one or a combination of two of octadecyl methacrylate, lauryl methacrylate or isodecyl methacrylate.

[0011] Furthermore, as a preferred embodiment, the cyclic monomer is selected from one or a combination of two or more of glycidyl methacrylate, isobornyl methacrylate, tetrahydrofuranyl methacrylate, and benzyl methacrylate.

[0012] Furthermore, as a preferred embodiment, the co-solvent is selected from one of tripropylene glycol, tripropylene glycol monomethyl ether, dipropylene glycol, and dipropylene glycol monomethyl ether.

[0013] Furthermore, as a preferred embodiment, the composite emulsifier is a combination of SDS and one or two of OP and Tween.

[0014] Furthermore, as a preferred embodiment, the water-soluble initiator is ammonium persulfate or potassium persulfate.

[0015] The present invention also provides a method for preparing the fluorine-free waterproofing agent emulsion for glass fiber filter paper, comprising the following steps:

[0016] Step 1: Synthesis of acrylic end-hydroxy silicone oil polyurethane: Add dihydroxy silicone oil and organic bismuth catalyst to the reaction kettle, heat it to 40-45°C, add isocyanate, keep it at 40-45°C for 2-3h, then add hydroxy acrylate, heat it to 80-90°C, keep it at 2-3h, and get a transparent solution, which is acrylic end-hydroxy silicone oil polyurethane;

[0017] Step 2: After the synthesized acrylic end-capped hydroxy silicone oil polyurethane, hydrophobic monomer, cyclic monomer, cosolvent, water, and composite emulsifier are dispersed at high speed, part of the mixed emulsion is added to the kettle, part of the initiator is added dropwise, heated to 70-80°C, and the rotation speed of the electric stirrer is set to 150-200r / min. After the system reacts for 15-20 minutes, a blue phenomenon will appear;

[0018] Step 3: Add the remaining mixed emulsion and the remaining initiator dropwise respectively, and control the continuous dripping within 3-4 hours; after the dripping is completed, heat the system to 85-90℃ and keep it warm for 1-2 hours; finally cool down and discharge the material to obtain a white fluorine-free waterproofing agent emulsion with a slightly light blue light.

[0019] The present invention also provides the use of the fluorine-free water-repellent agent in preparing water-resistant glass fiber filter paper, specifically:

[0020] The present invention also provides the use of the above-mentioned fluorine-free water repellent in the preparation of waterproof glass fiber air filter paper, specifically: the fluorine-free water repellent emulsion and the acrylic emulsion are mixed uniformly in proportion at room temperature, wherein the mass proportion of the fluorine-free water repellent emulsion in the mixed liquid is 20wt% to 50wt%; then the mixed liquid is impregnated, coated or sprayed on the glass fiber base paper, and dried in a drying oven at 130-160°C to obtain the waterproof glass fiber air filter paper.

[0021] Beneficial effects:

[0022] 1. The present invention adopts dihydroxy silicone oil to react with isocyanate, and then uses hydroxy acrylic acid to end-cap to prepare a hydrophobic monomer of acrylic acid-end-capped hydroxy silicone oil polyurethane, and then performs secondary polymerization with other functional acrylic monomers to prepare a fluorine-free waterproofing agent emulsion. This method controls the ratio of dihydroxy silicone oil to isocyanate, and reserves the silicon hydroxyl group to combine with the silicon oxygen bond on the glass fiber paper, which can effectively improve the binding force of the fluorine-free waterproofing agent with the glass fiber after drying and film formation, so that no additional cross-linking agent needs to be added.

[0023] 2. The present invention introduces cyclic high Tg acrylic acid in the secondary polymerization to further improve its water resistance. The glass fiber air filter paper obtained by blending the fluorine-free waterproofing agent emulsion prepared by the present invention with the acrylic latex for glass fiber paper and then impregnating and drying has better water resistance than ordinary waterproofing agents, and the hydrostatic pressure resistance can reach 20kPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is the infrared spectrum of the structure of formula (I) obtained in Example 1;

[0025] Figure 2 This is the particle size distribution diagram of the fluorine-free waterproofing agent emulsion prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Unless otherwise specified, the reagents and raw materials used in the examples and comparative examples of the present invention were purchased from the market.

[0028] Example 1

[0029] Synthesis of acrylic end-hydroxy silicone oil polyurethane: add 150g of dihydroxy silicone oil and 0.1g of organic bismuth catalyst to a 250ml kettle, heat to 40-45℃, add 11.1g of isocyanate, keep warm at 40-45℃ for 2h, then add 6.7g of hydroxy acrylate, heat to 80℃, keep warm for 2h, and obtain a transparent solution, which is acrylic end-hydroxy silicone oil polyurethane. Figure 1 As shown in FIG. 1 , it is the infrared spectrum of the acrylic acid-terminated hydroxy silicone oil polyurethane of this embodiment. The infrared spectrum shows that the characteristic peak of isocyanate (-NCO) at 2200 cm-1 disappears, that is, the isocyanate in IPDI is completely blocked. The characteristic peak of amide appears at about 1700 cm-1, and the characteristic peak of Si-OH at 2900 cm-1 still exists in the structural formula, indicating that the reaction is successful.

[0030] Example 2

[0031] 1. Preparation of fluorine-free waterproofing agent emulsion

[0032] Preparation of initiator: Mix 0.8g KPS and 40g water and stir evenly for use;

[0033] Add 45g of acrylic end-capped hydroxy silicone polyurethane synthesized in Example 1, 15g of octadecyl methacrylate, 15g of isobornyl methacrylate, 15g of benzyl methacrylate, 20g of tripropylene glycol, 1g of SDS, 2.6g of T-60, and 145g of pure water into a beaker and disperse at high speed for 10-15min. Take 1 / 3 of the mixed emulsion and add it into the kettle. Heat it to 75°C, add 1 / 4 of the initiator dropwise, and set the rotation speed of the electric stirrer to 150rmin. After the system reacts for about 15-20min, a blue phenomenon will appear.

[0034] The remaining mixed emulsion and the remaining initiator were added dropwise respectively, and the dripping was controlled to be completed within 3 hours. After the dripping was completed, the system was heated to 85°C and kept warm for 1 hour. Finally, the temperature was lowered and the material was discharged to obtain a white, slightly light blue, fluorine-free waterproofing agent emulsion with a solid content of 30.2%.

[0035] 2. Preparation of glass fiber air filter materials

[0036] Take 1g of the prepared fluorine-free waterproofing agent emulsion, 3g of acrylic glue, and 96g of water, mix and stir evenly, spread the formed micro-glass fiber paper flatly, immerse it in the diluent for 30s, take it out, and cure it at 150°C for 10min to obtain the glass fiber air filter material.

[0037] Example 3

[0038] 1. Preparation of fluorine-free waterproofing agent emulsion

[0039] Preparation of initiator: Mix 0.8g KPS and 40g water and stir evenly for use;

[0040] Add 50g of acrylic acid-terminated hydroxy silicone polyurethane synthesized in Example 1, 15g of octadecyl methacrylate, 15g of glycidyl methacrylate, 10g of benzyl methacrylate, 20g of tripropylene glycol monomethyl ether, 1g of SDS, 2.6g of OP-10, and 145g of pure water into a beaker and disperse at high speed for 10-15min. Take 1 / 3 of the mixed emulsion and add it into the kettle. Heat it to 75°C, add 1 / 4 of the initiator dropwise, and set the rotation speed of the electric stirrer to 150rmin. After the system reacts for about 15-20min, a blue phenomenon will appear.

[0041] The remaining mixed emulsion and the remaining initiator were added dropwise respectively, and the dripping was controlled to be completed within 3 hours. After the dripping was completed, the system was heated to 85°C and kept warm for one hour. Finally, the temperature was lowered and the material was discharged to obtain a white, slightly light blue, fluorine-free waterproofing agent emulsion with a solid content of 30.1%.

[0042] 2. Preparation of glass fiber air filter materials

[0043] Take 1g of the prepared fluorine-free waterproofing agent emulsion, 3g of acrylic glue, and 96g of water, mix and stir evenly, spread the formed micro-glass fiber paper flatly, immerse it in the diluent for 30s, take it out, and cure it at 150°C for 10min to obtain the glass fiber air filter material.

[0044] Example 4

[0045] 1. Preparation of fluorine-free waterproofing agent emulsion

[0046] Preparation of initiator: Mix 0.8g KPS and 40g water and stir evenly for use;

[0047] Add 50g of acrylic acid-terminated hydroxy silicone polyurethane synthesized in Example 1, 15g of octadecyl methacrylate, 15g of glycidyl methacrylate, 10g of isobornyl methacrylate, 20g of tripropylene glycol monomethyl ether, 0.6g of SDS, 1.3g of T-60, 1.3g of OP-10, and 145g of pure water into a beaker and disperse at high speed for 10-15min. Take 1 / 3 of the mixed emulsion and add it into the kettle. Heat it to 75°C, add 1 / 4 of the initiator dropwise, and set the rotation speed of the electric stirrer to 150rmin. After the system reacts for about 15-20min, a blue phenomenon will appear.

[0048] The remaining mixed emulsion and the remaining initiator were added dropwise respectively, and the dripping was controlled to be completed within 3 hours. After the dripping was completed, the system was heated to 85°C and kept warm for one hour. Finally, the temperature was lowered and the material was discharged to obtain a white, slightly blue, fluorine-free waterproofing agent emulsion with a solid content of 30.5%.

[0049] 2. Preparation of glass fiber air filter materials

[0050] Take 1g of the prepared fluorine-free waterproofing agent emulsion, 3g of acrylic glue, and 96g of water, mix and stir evenly, spread the formed micro-glass fiber paper flatly, immerse it in the diluent for 30s, take it out, and cure it at 150°C for 10min to obtain the glass fiber air filter material.

[0051] Example 5

[0052] 1. Preparation of fluorine-free waterproofing agent emulsion

[0053] Preparation of initiator: Mix 0.8g KPS and 40g water and stir evenly for use;

[0054] Add 55g of acrylic end-capped hydroxy silicone polyurethane synthesized in Example 1, 10g of octadecyl methacrylate, 10g of glycidyl methacrylate, 15g of tetrahydrofuran methacrylate, 30g of tripropylene glycol, 0.6g of SDS, 1.3g of T-60, 1.3g of OP-10, and 140g of pure water into a beaker and disperse at high speed for 10-15min. Take 1 / 3 of the mixed emulsion and add it into the kettle. Heat it to 75°C, add 1 / 4 of the initiator dropwise, and set the rotation speed of the electric stirrer to 150rmin. After the system reacts for about 15-20min, a blue phenomenon will appear.

[0055] The remaining mixed emulsion and the remaining initiator were added dropwise respectively, and the dripping was controlled to be completed within 3 hours. After the dripping was completed, the system was heated to 85°C and kept warm for one hour. Finally, the temperature was lowered and the material was discharged to obtain a white, slightly blue, fluorine-free waterproofing agent emulsion with a solid content of 30.5%.

[0056] 2. Preparation of glass fiber air filter materials

[0057] Take 1g of the prepared fluorine-free waterproofing agent emulsion, 3g of acrylic glue, and 96g of water, mix and stir evenly, spread the formed micro-glass fiber paper flatly, immerse it in the diluent for 30s, take it out, and cure it at 150°C for 10min to obtain the glass fiber air filter material.

[0058] Comparative Example 1

[0059] The 45g acrylic acid-terminated hydroxy silicone oil polyurethane and 15g octadecyl methacrylate in Example 2 were replaced with 60g octadecyl methacrylate, and the other amounts and operations remained unchanged to obtain a waterproofing agent emulsion, and the same method was used to prepare a glass fiber air filter material.

[0060] Comparative Example 2

[0061] The 45g acrylic acid-terminated hydroxyl silicone oil polyurethane and 15g octadecyl methacrylate in Example 1 were replaced with 30g acrylic acid-terminated hydroxyl silicone oil polyurethane and 30g octadecyl methacrylate, and other amounts and operations remained unchanged to obtain a waterproofing agent emulsion, and the same method was used to prepare a glass fiber air filter material.

[0062] Comparative Example 3

[0063] The 45g acrylic acid-terminated hydroxy silicone oil polyurethane, 15g octadecyl methacrylate, 15g isobornyl methacrylate, and 15g benzyl methacrylate in Example 1 were replaced with 45g acrylic acid-terminated hydroxy silicone oil polyurethane and 45g octadecyl methacrylate, while other amounts and operations remained unchanged, to obtain a waterproofing agent emulsion, and the same method was used to prepare a glass fiber air filter material.

[0064] Effect verification:

[0065] 1. Emulsion particle size test

[0066] The particle size of the fluorine-free water repellent emulsions prepared in Examples 2-5 of the present invention and Comparative Examples 1-3 was tested, and the size and distribution of the latex particles were tested using a Mastersizer 2000 laser particle size analyzer (Malvern, UK).

[0067] 2. Filtration efficiency and filtration resistance test

[0068] The filtration efficiency and filtration resistance of the glass fiber filter papers prepared in Examples 2-5 of the present invention and Comparative Examples 1-3 were tested using an American TSI-8130 automatic filter material tester.

[0069] 3. Stiffness test

[0070] The stiffness test of the glass fiber filter paper prepared in Examples 2-5 of the present invention and Comparative Examples 1-3 was performed

[0071] 4. Tensile strength

[0072] The stiffness test of the glass fiber filter paper prepared in Examples 2-5 of the present invention and Comparative Examples 1-3 was performed

[0073] 5. Hydrostatic pressure test

[0074] The glass fiber filter papers prepared in Examples 2-5 of the present invention and Comparative Examples 1-3 were subjected to a hydrostatic pressure test according to the national standard GB / T4744-2013.

[0075] The results are shown in the following chart:

[0076] Test data:

[0077]

[0078]

[0079] From the results in the table, it can be seen that the hydrophobic monomer of acrylic end-capped hydroxy silicone oil polyurethane is prepared by reacting dihydroxy silicone oil with isocyanate, and then end-capping with hydroxy acrylic acid, and then secondary polymerization with other functional acrylic monomers is carried out to prepare the fluorine-free waterproofing agent emulsion. This method controls the ratio of dihydroxy silicone oil to isocyanate, and reserves the silicon hydroxyl group to combine with the silicon oxygen bond on the glass fiber paper, which can effectively improve the bonding strength of the fluorine-free waterproofing agent with the glass fiber after drying and film formation, thereby achieving very excellent tensile strength, stiffness and water resistance without the need to add additional cross-linking agents. In addition, the introduction of cyclic high Tg acrylic acid in the secondary polymerization can further improve its water resistance, and the hydrostatic pressure resistance can reach 20kPa.

[0080] The above is only an implementation method of the invention, and does not limit the scope of patent protection. Those skilled in the art can make non-substantial changes or substitutions based on the invention, which still fall within the scope of patent protection.

Claims

1. A fluorine-free waterproofing agent emulsion for glass fiber filter paper, characterized in that The invention comprises the following components in parts by weight: 15-20 parts of acrylic end-capped hydroxy silicone oil polyurethane, 5-10 parts of hydrophobic monomer, 5-15 parts of cyclic monomer, 5-10 parts of cosolvent, 55-65 parts of water, 1-3 parts of composite emulsifier and 0.1-1 parts of water-soluble initiator.

2. The fluorine-free waterproofing agent emulsion for glass fiber filter paper according to claim 1, characterized in that: The acrylic acid-terminated hydroxy silicone oil polyurethane is prepared by reacting dihydroxy silicone oil with isocyanate and then blocking with hydroxy acrylic acid; the structural formula is shown in formula (I): Wherein: the molar ratio of dihydroxy silicone oil: isocyanate: hydroxy acrylic acid is controlled to be 1: 0.5-1.5: 0.5-1.

5.

3. The fluorine-free waterproofing agent emulsion for glass fiber filter paper according to claim 2, characterized in that: The acrylic acid-terminated hydroxy silicone oil polyurethane in the reaction system accounts for 30-70% of the reaction monomer mass ratio.

4. The fluorine-free waterproofing agent emulsion for glass fiber filter paper according to claim 2, characterized in that: The hydrophobic monomer is selected from one or a combination of octadecyl methacrylate, lauryl methacrylate or isodecyl methacrylate.

5. The fluorine-free waterproofing agent emulsion for glass fiber filter paper according to claim 2, characterized in that: The cyclic monomer is selected from one or a combination of two or more of glycidyl methacrylate, isobornyl methacrylate, tetrahydrofuranyl methacrylate, and benzyl methacrylate.

6. The fluorine-free waterproofing agent emulsion for glass fiber filter paper according to claim 2, characterized in that: The co-solvent is selected from one of tripropylene glycol, tripropylene glycol monomethyl ether, dipropylene glycol and dipropylene glycol monomethyl ether.

7. The fluorine-free waterproofing agent emulsion for glass fiber filter paper according to claim 2, characterized in that: The composite emulsifier is a combination of SDS and one or two of OP and Tween.

8. The fluorine-free waterproofing agent emulsion for glass fiber filter paper according to claim 2, characterized in that: The water-soluble initiator is ammonium persulfate or potassium persulfate.

9. A method for preparing the fluorine-free waterproofing agent emulsion for glass fiber filter paper according to any one of claims 2 to 8, characterized in that The steps include: Step 1: Synthesis of acrylic end-hydroxy silicone oil polyurethane: Add dihydroxy silicone oil and organic bismuth catalyst to the reaction kettle, heat it to 40-45°C, add isocyanate, keep it at 40-45°C for 2-3h, then add hydroxy acrylate, heat it to 80-90°C, keep it at 2-3h, and get a transparent solution, which is acrylic end-hydroxy silicone oil polyurethane; Step 2: After the synthesized acrylic end-capped hydroxy silicone oil polyurethane, hydrophobic monomer, cyclic monomer, cosolvent, water, and composite emulsifier are dispersed at high speed, part of the mixed emulsion is added to the kettle, part of the initiator is added dropwise, heated to 70-80°C, and the rotation speed of the electric stirrer is set to 150-200r / min. After the system reacts for 15-20 minutes, a blue phenomenon will appear; Step 3: Add the remaining mixed emulsion and the remaining initiator dropwise respectively, and control the continuous dripping within 3-4 hours; after the dripping is completed, heat the system to 85-90℃ and keep it warm for 1-2 hours; finally cool down and discharge the material to obtain a white fluorine-free waterproofing agent emulsion with a slightly light blue light.

10. Use of the fluorine-free water repellent agent as described in any one of claims 1 to 8 in the preparation of water-resistant glass fiber filter paper.

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