Process for the preparation of short-chain perfluoroalkyl block copolymers and their use as water- and oil-repellent finishing agents

Abstract

The application relates to the field of water and oil repellent coatings, and discloses a preparation method of a short-chain perfluoroalkyl block copolymer and application of the short-chain perfluoroalkyl block copolymer as a water and oil repellent finishing agent. The preparation method of the short-chain perfluoroalkyl block copolymer comprises the following steps: (1) preparation of a Macro-RAFT reagent; and (2) preparation of the short-chain perfluoroalkyl block copolymer mediated by the Macro-RAFT reagent. The short-chain perfluoroalkyl block copolymer is prepared by adopting a RAFT emulsion polymerization method, the arrangement order of short fluorine segments can be effectively controlled, the content of fluorine elements on the surface of the adhesive film is increased, the block copolymer emulsion has excellent water and oil repellency, various fabric finishing agents can be prepared, and the application prospect is good.

Description

Technical Field

[0001] This invention relates to the field of water- and oil-repellent coatings, specifically to a method for preparing a short-chain perfluoroalkyl block copolymer and its application as a water- and oil-repellent finishing agent. Background Technology

[0002] With the development of technology, functional textiles are widely used in life. Among them, waterproof and oil-proof finishing is widely used in various fields, such as self-cleaning coatings, sports and outdoor clothing coatings, and aerospace coatings. These excellent properties depend on the combination of low surface energy chemical components.

[0003] Low surface energy fluorocarbon-based coating materials have been widely used in the manufacture of hydrophobic and / or oleophobic coatings for fabrics, paper, films, leather, wood, and applications requiring anti-fingerprint, corrosion resistance, stain resistance, and self-cleaning properties. The preparation of oleophobic coatings has proven to be a particularly challenging task due to the significantly lower surface tension of oil (33.0 mN / m) compared to water (72.8 mN / m). It typically requires covering the oil with low surface energy fluorocarbon-based materials. For example, in the textile auxiliaries field, long-chain perfluorocarbons (PFCs) (≥C8) are highly effective in establishing low surface free energy surfaces due to the uniform and crystalline structure of their perfluoroalkyl side chains, which contain eight or more fluorocarbon atoms. However, long-chain perfluorosulfonic acids (≥C8) have been banned from use in textiles and are required to have zero emissions because their polymer products, perfluorooctanoic acid (PFOA) and perfluorooctanoic acid (PFOS), are toxic, highly stable, and bioaccumulative. Therefore, developing superhydrophobic and oleophobic coating surfaces using biocompatible and biodegradable coating materials remains a major challenge.

[0004] Currently, surfaces with lower surface free energy are typically modified with low surface energy fluorocarbon-based materials, which helps improve the surface's chemical composition and achieve superhydrophobic and oleophobic coatings. Today, academia and industry are showing great interest in using short-chain PFCs (≤C4), as this method is less prone to bioaccumulation. Unfortunately, these safer short-chain PFCs are highly flexible, easily forming amorphous structures, and readily undergoing short fluorine side chain reconstruction upon contact with water or other liquids, preventing them from achieving the original properties of PFCs. Furthermore, the effective fluorine chains in the chain segment do not all tend to be concentrated in the outermost layer. Therefore, there is an urgent need to develop a short-chain perfluoroalkyl water and oil repellent finishing agent that is "low-dosage, high-performance".

[0005] In recent years, research reports have indicated the use of short-chain fluorocarbon compounds to replace long-chain carbon compounds. For example, CN108250350B describes the preparation and application of a short-chain fluorinated copolymer water- and oil-repellent finishing agent, which uses short-chain perfluoroalkyl acrylates, non-fluorinated acrylate monomers, and crosslinking monomers to prepare a short-chain fluorinated copolymer fine emulsion. CN113249971B describes a core-shell type short-chain fluorinated acrylate fabric water- and oil-repellent finishing agent, its preparation method, and its application, using modified porous nano-silica as the core and a short-chain perfluorobutyl acrylate polymer as the shell to prepare a core-shell type short-chain fluorinated acrylate fabric water- and oil-repellent finishing agent. The methods described above utilize the restriction of the orientation structure of the short-chain fluoroalkyl side chain groups by the long alkyl side chains, thereby allowing fluorine elements to accumulate on the surface, resulting in better water- and oil-repellent properties. However, these methods do not address the issue of the block arrangement of functional monomers in the polymer. To address the above issues, there is an urgent need to develop a short-chain perfluoroalkyl block copolymer water- and oil-repellent finishing agent that requires low dosage and offers high performance. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a method for preparing and applying a short-chain perfluoroalkyl block copolymer water- and oil-repellent finishing agent. This invention utilizes a Macro-RAFT reagent to mediate and regulate the block arrangement of short-chain perfluoroalkyl groups, effectively ensuring the preferential arrangement of functional groups on the surface. This results in a lower surface free energy on the outermost layer, leading to better water and oil repellency and wider applicability.

[0007] The specific technical solution of this invention is as follows:

[0008] First, the present invention provides a method for preparing a short-chain perfluoroalkyl block copolymer water- and oil-repellent finishing agent, comprising the following steps:

[0009] (1) Preparation of Macro-RAFT reagent: First, dissolve the RAFT reagent in 1,4-dioxane, add acrylic monomer and initiator into a round bottom flask and stir magnetically for a period of time, then add 2,2,2-trifluoroethyl acrylate monomer and react to obtain Macro-RAFT reagent.

[0010] (2) Preparation of short-chain perfluoroalkyl block copolymers mediated by Macro-RAFT reagent: First, the Macro-RAFT reagent prepared in step (1) was added to deionized water along with an emulsifier and a co-emulsifier and stirred. A functional monomer was added and the mixture was passed through a cell disruptor to obtain a pre-emulsion. Finally, an initiator was added under nitrogen atmosphere to obtain a seed emulsion. Next, a film-forming monomer was added to the above seed emulsion and the mixture was passed through a cell disruptor to obtain a pre-emulsion. Finally, an initiator was added under nitrogen atmosphere to react and obtain the target emulsion.

[0011] In step (1), the Macro-RAFT reagent of this invention is a dicarboxylic trithiocarbonate. The dicarboxylic acid group of this type of bifunctional RAFT reagent has a high reactivity site. Furthermore, in the preparation of the Macro-RAFT reagent, only monomers, RAFT reagents, initiators, and water are required. This is a type of Macro-RAFT reagent prepared using organic solvents and without surfactants. The synthesized Macro-RAFT reagent can be repeatedly treated with water to provide a carrier for the bidirectional polymerization of the block copolymer in step (2).

[0012] In step (2), the pre-emulsion of the present invention is a first block polymer, and the block functional monomers are short-chain perfluorobutyl acrylate and octadecyl acrylate. The polymer contains short fluorine chains (C4), is biodegradable, has no harm to human health, is environmentally safe and environmentally friendly, and at the same time has excellent water and oil repellency properties due to long-chain fluorine (C6-C8).

[0013] This invention employs a distributed block copolymer preparation method to produce a short-chain perfluoroalkyl block copolymer. The first step involves preparing a seed emulsion using short-chain perfluorobutyl acrylate and octadecyl acrylate as functional monomers. The synergistic effect of the perfluoroalkyl and octadecyl side chains restricts the orientation of the short fluorine chains, causing them to arrange themselves on the outermost layer of the surface. This method uses the minimum amount of functional monomers to prepare the block copolymer, resulting in superior water and oil repellency.

[0014] Preferably, the RAFT reagent in step (1) is either S,S'-bis(R,R'-dimethyl-R”-acetic acid)-trithiocarbonate or 4-cyano-4-(((dodecylthio)thiocarbonyl)thio)valerate.

[0015] Preferably, in step (1), the mass ratio of RAFT reagent, acrylic monomer, 2,2,2-trifluoroethyl acrylate, 1,4-dioxane and initiator is 1-3:10-15:8-10:50-60:0.2-0.5.

[0016] Preferably, the preparation time of the Macro-RAFT reagent in step (1) is 2 hours.

[0017] Preferably, the functional monomers in step (2) are short-chain perfluorobutyl acrylate and octadecyl acrylate.

[0018] Preferably, the emulsifier is DNS-86.

[0019] Preferably, the emulsifier is n-hexadecane.

[0020] Preferably, the film-forming monomers in step (2) are butyl acrylate and methyl methacrylate.

[0021] Preferably, the initiator in step (1) is 4,4′ azo acid (4-cyanovaleric acid); and the initiator in step (2) is either ammonium persulfate or azobisisobutyronitrile.

[0022] Preferably, the mass ratio of the Macro-RAFT reagent, functional monomer, and film-forming monomer is 1-3:15-20:25-30.

[0023] Preferably, the mass ratio of the initiator, emulsifier, and co-emulsifier is 1-2:4-5:5-6 of the total monomer percentage.

[0024] Second, the present invention provides an application of the above-mentioned finishing agent in water- and oil-repellent finishing of fabrics, specifically: the finishing agent is first prepared by adding water to prepare the finishing agent, and then the fabric is immersed in the finishing solution. After pre-drying and baking in sequence, the water- and oil-repellent finishing of the fabric is achieved.

[0025] Preferably, the concentration of the finishing agent in the finishing solution is 60-80 g / L;

[0026] The mass ratio of the fabric to the finishing solution is 1:30;

[0027] During the impregnation process, the impregnation method is two-immersion and two-rolling.

[0028] After impregnation, the liquid extraction rate of the fabric is 80-90%.

[0029] The pre-drying temperature is 80-90℃, and the pre-drying time is 3-5 minutes.

[0030] The baking temperature is 150-160℃, and the baking time is 2-3 minutes.

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] (1) The present invention prepares a short-chain perfluoroalkyl block copolymer water and oil repellent finishing agent. The Macro-RAFT reagent is prepared by using dicarboxylic trithiocarbonate. The dicarboxylic group has a high reactive site, which provides a carrier for the subsequent RAFT-mediated preparation of block copolymers.

[0033] (2) The block copolymer prepared by the distributed block copolymer method of this invention first preferentially inserts a small amount of functional monomers, short-chain perfluoroacrylate and octadecyl acrylate, to prepare a seed emulsion. Then, a short-chain perfluoroalkyl pentablock copolymer emulsion is prepared by adding film-forming monomers. By regulating the preferential arrangement of fluorinated segments on the outermost layer through RAFT-mediated control, the accumulation of fluorine elements on the surface is promoted, resulting in a lower surface energy for the copolymer emulsion and giving the copolymer better water and oil repellency properties, such as… Figure 1As shown, the addition of short-chain perfluoroacrylates not only results in lower surface energy but also facilitates degradation, posing no harm to humans or the environment.

[0034] (3) The short-chain perfluoroalkyl block copolymer water- and oil-repellent finishing agent of the present invention, based on emulsion polymerization, selects the best process parameters to achieve the best water- and oil-repellent effect, thereby indirectly increasing the added value of the product. Attached Figure Description

[0035] Figure 1 Schematic diagram of the water and oil repellency properties of block copolymers and random copolymers;

[0036] Figure 2 Infrared characterization of short-chain perfluoroalkyl block copolymers;

[0037] Figure 3 A schematic diagram of the synthetic structure of RAFT-mediated regulation of short-chain perfluoroalkyl block copolymers;

[0038] Figure 4 Diagram showing the water and oil repellency properties of finished fabrics. Detailed Implementation

[0039] The present invention will be further described below with reference to embodiments.

[0040] The following embodiments are intended to enable those skilled in the art to more fully understand the present invention, but do not limit the invention in any way.

[0041] Example 1

[0042] (1) Preparation of Macro-RAFT reagent: First, 0.35g of S,S'-bis(R,R'-dimethyl-R”-acetic acid)-trithiocarbonate RAFT reagent was dissolved in 17.8g of 1,4-dioxane. Then, 3.6g of acrylic acid monomer and 0.6g of initiator ammonium persulfate were added into a round-bottom flask and magnetically stirred for 2h. Then, 1.93g of 2,2,2-trifluoroethyl acrylate monomer was added and reacted for another 2h to obtain Macro-RAFT reagent.

[0043] (2) Macro-RAFT reagent-mediated preparation of short-chain perfluoroalkyl block copolymers: First, 0.36g Macro-RAFT reagent prepared in step (1) was added to 36g deionized water along with 0.24g DNS-86 and 0.27g n-hexadecane and stirred. 2.7g short-chain perfluorobutyl acrylate and 2.7g octadecyl acrylate were added and processed using a cell disruptor to obtain a pre-emulsion. Finally, under nitrogen atmosphere, 0.054g ammonium persulfate was added and reacted at 75℃ for 4h to obtain a seed emulsion. Next, 4.5g butyl acrylate, 4.5g methyl methacrylate, 0.36g DNS-86, and 0.36g n-hexadecane were added to the above seed emulsion and processed using a cell disruptor to obtain a pre-emulsion. Finally, under nitrogen atmosphere, 0.09g ammonium persulfate was added and reacted at 75℃ for 4h to obtain the target emulsion, which is the short-chain perfluoroalkyl block copolymer.

[0044] Short-chain perfluorobutyl acrylate: CHCOOCH2CH2(CF2)3CF3 was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0045] like Figure 2 The image shown is an infrared spectrum of short-chain perfluoroalkyl acrylate block copolymers. It can be seen that the peak wavelengths at 2917 and 2841 cm⁻¹ are... -1 The characteristic absorption peak of CH is at 1741 cm⁻¹. -1 The peak at 1127 cm⁻¹ represents the stretching vibration of CO, which is composed of SA, MMA, and BA; -1 The presence of a distinct CF stretching vibration peak indicates that C4F participated in the reaction. This demonstrates that the short-chain perfluoroalkyl block copolymer was successfully synthesized from the polymerized monomers.

[0046] Example 2

[0047] (1) Preparation of Macro-RAFT reagent: First, 0.35g of S,S'-bis(R,R'-dimethyl-R”-acetic acid)-trithiocarbonate RAFT reagent was added to 17.8g of 1,4-dioxane and dissolved. Then, 3.6g of acrylic acid monomer and initiator were added and placed in a round-bottom flask and magnetically stirred for 2 hours. Then, 1.93g of 2,2,2-trifluoroethyl acrylate monomer was added and reacted for another 2 hours to obtain Macro-RAFT reagent.

[0048] (2) Preparation of short-chain perfluoroalkyl block copolymer mediated by Macro-RAFT reagent: First, 0.36g Macro-RAFT reagent prepared in step (1) was added to 36g deionized water and stirred. Then, 2.7g short-chain perfluorobutyl acrylate, 2.7g octadecyl acrylate, 4.5g butyl acrylate and 4.5g methyl methacrylate were added and mixed. The mixture was then passed through a cell disruptor to obtain a pre-emulsion. Finally, under nitrogen atmosphere, 0.144g ammonium persulfate was added and reacted at 75℃ for 4h to obtain the target emulsion.

[0049] Example 3

[0050] (1) Preparation of Macro-RAFT reagent: First, 0.35g of 4-cyano-4-(((dodecylthio)thiocarbonyl)thio)valerate RAFT reagent was added to 17.8g of 1,4-dioxane and dissolved. Then, 3.6g of acrylic acid monomer and initiator were added and placed in a round-bottom flask and stirred magnetically for 2 hours. Then, 1.93g of 2,2,2-trifluoroethyl acrylate monomer was added and reacted for another 2 hours to obtain Macro-RAFT reagent.

[0051] (2) Preparation of short-chain perfluoroalkyl block copolymers mediated by Macro-RAFT reagent: First, 0.36g of Macro-RAFT reagent prepared in step (1) was added to 36g of deionized water along with 0.24g of DNS-86 and 0.27g of n-hexadecane and stirred. 2.7g of short-chain perfluorobutyl acrylate and 2.7g of octadecyl acrylate were added and processed using a cell disruptor to obtain a pre-emulsion. Finally, 0.054g of ammonium persulfate was added under nitrogen atmosphere to obtain a seed emulsion. Next, 4.5g of butyl acrylate, 4.5g of methyl methacrylate, 0.36g of DNS-86, and 0.36g of n-hexadecane were added to the above seed emulsion and processed using a cell disruptor to obtain a pre-emulsion. Finally, 0.09g of ammonium persulfate was added under nitrogen atmosphere and reacted at 75℃ for 4h to obtain the target emulsion. A schematic diagram of the synthetic structure of the short-chain perfluoroalkyl block copolymer mediated by Macro-RAFT is shown below. Figure 3 As shown.

[0052] Example 4

[0053] (1) Preparation of Macro-RAFT reagent: First, 0.35g of S,S'-bis(R,R'-dimethyl-R”-acetic acid)-trithiocarbonate RAFT reagent was added to 17.8g of 1,4-dioxane and dissolved. Then, 3.6g of acrylic acid monomer and initiator were added and placed in a round-bottom flask and magnetically stirred for 2 hours. Then, 1.93g of 2,2,2-trifluoroethyl acrylate monomer was added and reacted for another 2 hours to obtain Macro-RAFT reagent.

[0054] (2) Preparation of short-chain perfluoroalkyl block copolymers mediated by Macro-RAFT reagent: First, 0.36g of Macro-RAFT reagent prepared in step (1) was added to 36g of deionized water along with 0.12g of DNS-86 and 0.13g of n-hexadecane and stirred. Then, 1.35g of short-chain perfluorobutyl acrylate and 1.35g of octadecyl acrylate were added and reacted with a cell disruptor to obtain a pre-emulsion. Finally, under nitrogen atmosphere, 0.027g of ammonium persulfate was added and reacted at 75℃ for 4h to obtain a seed emulsion. Next, 4.5g of butyl acrylate, 4.5g of methyl methacrylate, 0.36g of DNS-86, and 0.36g of n-hexadecane were added to the above seed emulsion and reacted with a cell disruptor to obtain a pre-emulsion. Finally, under nitrogen atmosphere, 0.09g of ammonium persulfate was added and reacted at 75℃ for 4h to obtain the target emulsion.

[0055] Control group 1

[0056] Preparation of short-chain perfluoroalkyl block copolymers without RAFT reagent regulation: 0.72g DNS-86 and 0.57g n-hexadecane were added to 36g deionized water and stirred. Then, 2.7g short-chain perfluorobutyl acrylate, 2.7g octadecyl acrylate, 4.5g butyl acrylate and 4.5g methyl methacrylate were added and mixed. The mixture was then passed through a cell disruptor to obtain a pre-emulsion. Finally, under nitrogen atmosphere, 0.144g ammonium persulfate was added and the mixture was reacted at 75℃ for 4h to obtain the target emulsion.

[0057] Control group 2: Commercially available long-chain perfluorinated finishing agents (Cn≥6F) 2n+1 ).

[0058] Example 5

[0059] The finishing agents prepared in Examples 1-4 and Control Groups 1-2 were used to finish pure cotton fabrics. The polymer emulsions synthesized in Examples 1-4 and Control Groups 1-2 were diluted and used as finishing solutions on pure cotton fabrics. The concentration of the finishing solution was 80 g / L.

[0060] Use the prepared finishing solution to perform water and oil repellency treatment on the cotton fabric:

[0061] First, prepare the liquor ratio of 1:30. Then, immerse the cotton fabric in each of the finishing solutions, repeating the process twice (with a liquid retention rate of 80%). Dry the fabric in an 80°C oven for 4 minutes, and then bake it at 160°C for 3 minutes to complete the water and oil repellency treatment.

[0062] Test case

[0063] The water and oil repellency properties of the pure cotton fabric treated in Example 5 were tested using the following method: A DSA100 (Krüss, Germany) contact angle measuring device (whose measurement system is based on the interface shape analysis method to measure the contact angle of an object surface) was used to measure the static contact angles of water and salad oil on the fabric surface, i.e., the water contact angle and the oil contact angle. The results are shown in Table 1.

[0064] Table 1. Contact angles of Examples 1-4 and Control Groups 1-2

[0065] Water contact angle Oil contact angle Example 1 152.5° 142.4° Example 2 151.3° 130.2° Example 3 153.6° 133.7° Example 4 154.2° 110.8° Control group 1 145.3° 122.1° Control group 2 148.1° 145.3°

[0066] As shown in Table 1, the finishing agents prepared in Examples 1-4 and Control Groups 1-2 in Implementation Case 5, when used to finish pure cotton fabric, all exhibited good water repellency with water contact angles greater than 150°. However, in terms of effectiveness, Example 1 showed better oil repellency, reaching 142.4°. Compared to Implementation Cases 2-4, this highlights the high activity of the dicarboxylic acid RAFT reagent. The prepared Macro-RAFT reagent can effectively regulate the arrangement sequence of short-chain perfluoroalkyl groups, allowing the short fluorine chains to preferentially arrange on the outermost layer, resulting in fluorine accumulation on the surface and a lower surface free energy. Compared to Control Group 2, and compared to commercially available long-chain perfluorofluorinated finishing agents (C... n≥6 F 2n+1 The oil-repellent effect is similar. The short-chain perfluoroalkyl block copolymer water- and oil-repellent finishing agent prepared by this invention achieves the intended purpose of the invention.

[0067] like Figure 1 The diagram illustrates the water and oil repellency of block copolymers and random copolymers. It shows that in random copolymers, most functional segments are trapped within the film structure, causing oil and water to adhere to the surface. In block copolymers, most functional segments (fluorinated side chains and crystalline side chains) are enriched on the surface, induced by thermodynamic forces. Therefore, these functional segments induce low surface energy. Consequently, block copolymers prepared with RAFT reagents effectively increase the surface fluorine content, giving their surfaces non-adhesive properties.

[0068] like Figure 2 The image shown is an infrared characterization of the short-chain perfluoroalkyl block copolymer, indicating that the short-chain perfluoroalkyl block copolymer was successfully synthesized by the polymerizing monomers.

[0069] like Figure 3 The diagram shown is a schematic of the synthetic structure of a RAFT-mediated short-chain perfluoroalkyl block copolymer, demonstrating that the block copolymer prepared by RAFT-mediated regulation can preferentially synthesize C4F and SA monomers in the outermost layer, so that low surface energy groups are in the outermost layer of the chain segment.

[0070] like Figure 4The figure shown is a diagram illustrating the water and oil repellency properties of the treated fabric, demonstrating that the block copolymer-treated fabric has good water and oil repellency properties.

[0071] Unless otherwise specified, the raw materials and equipment used in this invention are all commonly used in the field; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0072] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, and equivalent transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a short-chain perfluoroalkyl block copolymer, characterized in that, Includes the following steps: (1) First, dissolve the RAFT reagent S,S'-bis(R,R'-dimethyl-R''-acetic acid)-trithiocarbonate in 1,4-dioxane, add acrylic monomer and initiator into the reactor and stir magnetically, then add 2,2,2-trifluoroethyl acrylate monomer and react to obtain Macro-RAFT reagent. (2) First, add the Macro-RAFT reagent prepared in step (1) along with a portion of emulsifier and a portion of co-emulsifier to deionized water and stir. Then, add the functional monomer and obtain a pre-emulsion by a cell disruptor. Finally, under nitrogen atmosphere, add a portion of initiator to obtain a seed emulsion. The film-forming monomer, the remaining emulsifier, and the remaining co-emulsifier are then added to the seed emulsion and processed through a cell disruptor to obtain a pre-emulsion. Finally, under a nitrogen atmosphere, the remaining initiator is added to react and obtain the target emulsion, which is a short-chain perfluoroalkyl block copolymer. The functional monomer is a mixture of any one of octadecyl acrylate and octadecyl methacrylate with short-chain perfluorobutyl acrylate; The film-forming monomer is any one or two of butyl acrylate, methyl methacrylate, methyl acrylate, and hexyl acrylate; The mass ratio of the Macro-RAFT reagent, functional monomer, and film-forming monomer is 1-3:15-20:25-30.

2. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of the RAFT reagent, acrylic monomer, 2,2,2-trifluoroethyl acrylate, 1,4-dioxane and initiator is 1-3:10-15:8-10:50-60:0.2-0.

5.

3. The preparation method according to claim 1, characterized in that, In step (1), the magnetic stirring time is 2-3 hours; The reaction time is 2-3 hours.

4. The preparation method according to claim 1, characterized in that, In step (2), the emulsifier is any one of OP-10, sodium dodecyl sulfate, and DNS-86; The co-emulsifier is either n-hexadecane or n-hexadecyl alcohol.

5. The preparation method according to claim 1, characterized in that, The initiator is any one of ammonium persulfate, potassium persulfate, azobisisobutyronitrile, 4,4′ azo acid (4-cyanovaleric acid).

6. The application of the short-chain perfluoroalkyl block copolymer prepared by the method according to any one of claims 1 to 5 as a water- and oil-repellent finishing agent.

7. The application as described in claim 6, characterized in that, include: First, the finishing agent is mixed with water to prepare a finishing solution. Then, the fabric is immersed in the finishing solution and pre-dried and baked in sequence to achieve water and oil repellency finishing of the fabric. The concentration of the finishing agent in the finishing solution is 60-80 g / L; The mass ratio of the fabric to the finishing solution is 1:20-30; During the impregnation process, the impregnation method is two-immersion and two-rolling. After impregnation, the liquid extraction rate of the fabric is 60-90%. The pre-drying temperature is 70-100℃, and the pre-drying time is 3-6 minutes; The baking temperature is 150-170℃, and the baking time is 2-4 minutes.

Images