Short-chain fluorinated polyacrylate three-proof finishing agent for cotton, preparation method and application thereof

Abstract

The present invention provides a short-chain fluorinated polyacrylate three-proof finishing agent for cotton and a preparation method thereof. The method includes: dissolving a compounded emulsifier in deionized water, mixing fluorinated monomers and various acrylic monomers in proportion and then dropping them into the emulsifier aqueous solution to form a pre-emulsion under vigorous stirring; then performing ultrasonic dispersion through an ultrasonic cell disruptor under an ice bath to form a fine emulsified pre-emulsion, and subsequently transferring the fine emulsion into a three-necked flask. After slowly heating to the reaction temperature under an N2 atmosphere, an aqueous solution of an initiator is uniformly injected through a micro-injection pump to initiate the reaction. After the initiator is completely added dropwise, the reaction is continued while maintaining the temperature, and then the reaction is stopped and cooled to room temperature to obtain the short-chain fluorinated polyacrylate emulsion. The short-chain fluorinated polyacrylate three-proof finishing agent prepared by the present invention does not contain PFOS and PFOA, meets the environmental protection requirements, and has excellent water, oil and stain resistance properties.

Description

Technical Field

[0001] The present invention relates to a short-chain fluorinated polyacrylate three-proof finishing agent for cotton, a preparation method thereof and an application thereof, belonging to the field of textile dyeing and finishing auxiliaries. Background Art

[0002] The three-proof finishing of fabrics mainly refers to the finishing with low surface energy substances, which reduces the surface tension of the fabric surface to be less than the surface energy of water and various other oil stains, so that the fabric surface is not easily wetted and contaminated by water, oil and other stains. The waterproof finishing of fabrics is widely applied, not only for outerwear, sportswear, work clothes, etc., but also for outdoor products such as canvas and rainproof tarpaulins. In addition, in the field of medical protection, masks, protective clothing, etc. require functions such as waterproof, oil-proof and alcohol-proof. Therefore, the development of three-proof finishing agents has important social and economic value.

[0003] The three-proof finishing agents are mainly divided into fluorinated finishing agents and non-fluorinated finishing agents. The fluorinated finishing agents have excellent water and oil repellency performance, but the cost is relatively high. Traditional long-chain fluorinated acrylates are prohibited from use because they generate perfluorooctane sulfonyl compounds (PFOS) and perfluorooctanoic acid (PFOA), which have biological permanent accumulation and are difficult to degrade. Compared with traditional C8-type three-proof finishing agents, short-chain fluorinated three-proof finishing agents (C n F 2n+1 , n≤6) do not contain prohibited substances such as PFOS, PFOA, and formaldehyde, are relatively easy to degrade, and are an environmentally friendly type of three-proof finishing agent. By virtue of the low surface tension of fluorine atoms, short-chain fluorinated finishing agents can achieve excellent waterproof, oil-proof and stain-proof effects on different fabrics, meeting the requirements of the current application market and corresponding environmental protection regulations.

[0004] The research and product development of short-chain fluorinated polyacrylate three-proof finishing agents in China started relatively late, and the R & D technology is weak compared with foreign countries. At present, the production technology of short-chain fluorinated polyacrylate three-proof finishing agents is mainly monopolized by foreign companies such as 3M, Daikin, and Asahi Glass in the United States, and domestic production basically remains at the experimental stage. Summary of the Invention

[0005] The purpose of the present invention is to provide a short-chain fluorinated polyacrylate three-proof finishing agent for cotton, which does not contain APEO, PFOS and PFOA, meets the environmental protection requirements, and has excellent waterproof, oil-proof and stain-resistant performance.

[0006] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0007] A preparation method of a short-chain fluorinated polyacrylate three-proof finishing agent for cotton, the method comprising the following steps:

[0008] S1, pre-emulsification process:

[0009] The cationic emulsifier and the nonionic emulsifier are compounded in a mass ratio of 2:1 to 3:1 and dissolved in water, and are fully dissolved under stirring to obtain an aqueous emulsifier solution;

[0010] Take fluorine-containing monomers, long-chain acrylate monomers and other functional acrylate monomers, mix them evenly and dropwise add them into the aqueous emulsifier solution within 15 - 20 min, and form a pre-emulsion under vigorous stirring;

[0011] The total amount of the cationic emulsifier and the nonionic emulsifier used accounts for 6% - 8% of the total mass of the three monomers; the fluorine-containing monomer accounts for 37% - 50% of the total mass of the monomers, the long-chain acrylate monomer accounts for 20% - 30% of the total mass of the monomers, and the balance is other functional acrylate monomers, and the total mass of the monomers is counted as 100%;

[0012] S2, fine emulsification process:

[0013] The pre-emulsion prepared in S1 is ultrasonically dispersed in an ice bath to form a fine emulsified pre-emulsion;

[0014] S3, polymerization process:

[0015] The fine emulsified pre-emulsion prepared in S2 is slowly heated to the reaction temperature of 60 - 80 °C under a N2 atmosphere; the aqueous initiator solution is uniformly injected into the reaction system through a micro-injection pump to initiate the reaction. After the initiator is completely added dropwise, the reaction is continued to be kept warm for 3 - 6 h, and then the reaction is stopped and cooled to room temperature. The obtained fine emulsion is a short-chain fluorine-containing polyacrylate three-proof finishing agent for cotton.

[0016] Preferably, the amount of water mixed with the emulsifier in S1 is generally 2.5 to 3 times the total mass of the monomers.

[0017] Preferably, the cationic emulsifier in S1 is one of cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, octadecyltrimethylammonium bromide or octadecyltrimethylammonium chloride; the nonionic emulsifier is one of fatty alcohol polyoxyethylene ethers. Preferably, the cationic emulsifier is cetyltrimethylammonium bromide CTAB, and the nonionic emulsifier is fatty alcohol polyoxyethylene ether AEO-9.

[0018] Preferably, the cationic emulsifier and the nonionic emulsifier in S1 are CTAB and AEO-9 respectively, the mass ratio of CTAB and AEO-9 is 3:1, and their amount accounts for 8% of the total mass of the monomers.

[0019] Preferably, in S1, the fluorinated monomer is perfluorohexylethyl acrylate, accounting for 50% of the total mass of the monomers; the long-chain acrylate monomer is octadecyl acrylate, accounting for 25% of the total mass of the monomers; and the balance is other functional acrylate monomers. The other functional acrylate monomers are a mixture of methyl methacrylate, butyl acrylate, and glycidyl methacrylate, or a mixture of methyl methacrylate, butyl acrylate, and 2-hydroxyethyl acrylate. Preferably, the amount of GMA is 2-4% of the total mass of the monomers, and optimally 3%. Preferably, MMA:BA = 1:1-3, and more preferably MMA:BA = 1:3. Preferably, the mass ratio of C6F:SA is 2:1.

[0020] Preferably, in S1, the fluorinated monomer is perfluorohexylethyl acrylate (C6F), and its amount accounts for 50% of the total mass of the monomers; the long-chain acrylate monomer is octadecyl acrylate (SA), and its amount accounts for 25% of the total mass of the monomers; the other functional acrylate monomers are a mixture of methyl methacrylate (MMA), butyl acrylate (BA), and glycidyl methacrylate (GMA) with a mass ratio of 3:1:1, and its amount accounts for 25% of the total mass of the monomers.

[0021] Preferably, the pre-emulsion is formed under vigorous stirring in S1, where the stirring speed of the stirrer is 500-800 r / min and the stirring time is 30-50 min. The preferred stirring speed is 600 r / min and the time is 45 min.

[0022] Preferably, the ultrasonic dispersion conditions in S2 are as follows: using a ultrasonic cell disruptor with a power of 200-400 w, and the ultrasonic time is 5-15 min. The preferred power is 270 w and the time is 8 min.

[0023] Preferably, the initiator in S3 is 2,2'-azobis(2-methylpropionamidine) dihydrochloride or 2,2'-azobis(2-methyl-N-(2-hydroxyethyl)propionamide) dihydrochloride, and its amount accounts for 0.2%-1% of the total mass of the monomers. Preferably, 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AIBA), and its amount accounts for 0.6% of the total mass of the monomers.

[0024] Preferably, the reaction temperature in S3 is 75°C and the holding reaction time is 5 h.

[0025] Preferably, the injection rate of the micro-injection pump in S3 is 100 μl / min - 140 μl / min, and the injection time is 60-80 min. The preferred injection rate is 110 μl / min and the injection time is 70 min.

[0026] A short-chain fluorinated polyacrylate three-proof finishing agent for cotton obtained by the preparation method of the present invention.

[0027] Application of the short-chain fluorinated polyacrylate three-proof finishing agent for cotton in three-proof finished fabrics. When using this three-proof finishing agent, it can be diluted to an appropriate concentration. Preferably, this three-proof finishing agent is used for the three-proof finishing of cotton fabrics, and the specific steps are as follows:

[0028] Immerse the pre-treated cotton fabric (thoroughly cleaned before finishing) in the three-proof finishing solution with a concentration of 50 g / l for 20 min, and pad it through a padding mangle once (padding rate 70%-80%). Then pre-dry the padded cotton fabric at 80 °C for 4 min, and then cure it at 170 °C for 4 min to obtain the three-proof finished cotton fabric.

[0029] The beneficial effects of the present invention are as follows:

[0030] 1. The short-chain fluorinated polyacrylate three-proof finishing agent for cotton prepared by the present invention does not contain APEO, perfluorooctane sulfonyl compounds (PFOS) and perfluorooctanoic acid (PFOA) in its decomposition products, does not have permanent bioaccumulation, and meets the environmental protection requirements.

[0031] 2. The present invention adopts the miniemulsion polymerization method and utilizes its droplet nucleation mechanism, which can effectively avoid the problem of the migration of fluorinated monomers from water to micelles, thereby reducing the gel phenomenon. Compared with conventional emulsion polymerization, it has the advantages of high reaction rate, high conversion rate, controllable particle size, etc., and the reaction process is relatively simple and easy to control.

[0032] 3. The short-chain fluorinated polyacrylate three-proof finishing agent for cotton prepared by the present invention is a cationic emulsion with a positive charge, which can effectively improve the binding force with cotton fabrics, and the cross-linking agent contained in the finishing agent can react with -OH on the surface of cotton fabrics to further improve the stability. Description of the Drawings

[0033] Figure 1 shows the influence of the finishing process on the contact angle and whiteness of cotton fabrics;

[0034] Figure 2 shows the SEM images of cotton fabrics before and after finishing, where (a1-3) is raw cotton and (b1-3) is finished cotton, and the magnification is 500, 2000, and 5000 times. Detailed Embodiments

[0035] The following are specific examples to further illustrate the technical solutions of the present invention. It should be understood that the implementation of the present invention is not limited to the following examples, and any form of modification and / or change made to the present invention will fall within the protection scope of the present invention.

[0036] In the present invention, unless otherwise specified, all parts and percentages are in weight units, and the equipment and raw materials used can be obtained from the market or are commonly used in the art. The methods in the following examples are conventional methods in the art unless otherwise specified.

[0037] Example 1

[0038] A preparation method of a short-chain fluorinated polyacrylate three-proof finishing agent for cotton, the specific steps of the method are as follows:

[0039] S1, pre-emulsification process:

[0040] Dissolve 0.48 g of cetyltrimethylammonium bromide and 0.16 g of fatty alcohol polyoxyethylene ether AEO-9 in 20 ml of deionized water, and stir to dissolve it completely. Take 4 g of perfluorohexylethyl acrylate, 2 g of octadecyl acrylate, 0.5 g of methyl methacrylate, and 1.5 g of butyl acrylate. After mixing evenly, dropwise add it into the emulsifier aqueous solution drop by drop with a dropper within 15 - 20 min, and stir at 700 r / min for 40 min to form a pre-emulsion;

[0041] Polymerization monomer formula: 50% of perfluorohexylethyl acrylate, 25% of octadecyl acrylate, 6.25% of methyl methacrylate, and 18.75% of butyl acrylate.

[0042] S2, fine emulsification process:

[0043] Ultrasonically disperse the pre-emulsion prepared in S1 in an ice bath with an ultrasonic cell disrupter (power 270 w) for 8 min to form a fine emulsified pre-emulsion.

[0044] S3, polymerization process:

[0045] Transfer the fine emulsified pre-emulsion prepared in S2 into a three-necked flask. After slowly heating to 75 °C under a N2 atmosphere, dissolve 0.048 g of initiator 2,2'-azobis(2-methylpropionamidine) dihydrochloride in 5 ml of aqueous solution and inject it into the reaction system at a constant speed of 110 μl / min through a micro-injection pump to initiate the reaction. After the initiator is added dropwise for 75 min, continue to keep the reaction at a constant temperature for 5 h, and then stop the reaction and cool it to room temperature to obtain the fine emulsion (solid content 25%).

[0046] Example 2 (comparison with Example 1, without the long-chain acrylate monomer octadecyl acrylate)

[0047] A preparation method of a short-chain fluorinated polyacrylate three-proof finishing agent for cotton, the specific steps of the method are as follows:

[0048] S1, pre-emulsification process:

[0049] Dissolve 0.42 g of cetyltrimethylammonium chloride and 0.14 g of fatty alcohol polyoxyethylene ether AEO-9 after compounding in 19 ml of deionized water, and stir to dissolve it fully. Take 6 g of perfluorohexylethyl acrylate, 0.5 g of methyl methacrylate, and 1.5 g of butyl acrylate. After mixing evenly, use a dropper to drop it into the emulsifier aqueous solution drop by drop within 15 - 20 min, and stir at 600 r / min for 50 min to form a pre-emulsion;

[0050] Polymerization monomer formula: perfluorohexylethyl acrylate 75%, methyl methacrylate 6.25%, butyl acrylate 18.75%.

[0051] S2, fine emulsification process:

[0052] Ultrasonically disperse the pre-emulsion prepared in S1 in an ice bath through an ultrasonic cell disruptor (power 300 w) for 6 min to form a fine emulsified pre-emulsion;

[0053] S3, polymerization process:

[0054] Transfer the fine emulsified pre-emulsion prepared in S2 into a three-necked flask. Under a N2 atmosphere, slowly heat it to 70 °C, then dissolve 0.064 g of initiator 2,2'-azobis(2-methylpropionamidine) dihydrochloride in 6 ml of aqueous solution and inject it into the reaction system at a constant speed of 120 μl / min through a micro-injection pump to initiate the reaction. After the initiator is added dropwise for 70 min, continue to keep the reaction at a constant temperature for 5 h, and then stop the reaction and cool it to room temperature to obtain the fine emulsion (solid content 25.2%).

[0055] Example 3

[0056] A preparation method of a short-chain fluorinated polyacrylate three-proof finishing agent for cotton, and the specific steps of the method are as follows:

[0057] S1, pre-emulsification process:

[0058] Dissolve 0.36 g of cetyltrimethylammonium bromide and 0.12 g of fatty alcohol polyoxyethylene ether AEO-9 after compounding in 17 ml of deionized water, and stir to dissolve it fully. Take 3 g of perfluorohexylethyl acrylate, 3 g of octadecyl acrylate, 0.5 g of isobornyl methacrylate, and 1.5 g of butyl acrylate. After mixing evenly, use a dropper to drop it into the emulsifier aqueous solution drop by drop within 15 - 20 min, and stir at 700 r / min for 40 min to form a pre-emulsion;

[0059] Polymerization monomer formula: perfluorohexylethyl acrylate 37.5%, octadecyl acrylate 37.5%, isobornyl methacrylate 6.25%, butyl acrylate 18.75%.

[0060] S2, fine emulsification process:

[0061] The pre-emulsion prepared in S1 was ultrasonically dispersed by an ultrasonic cell crusher (power 240w) under ice bath for 10min to form a fine emulsified pre-emulsion;

[0062] S3, aggregation process:

[0063] The fine emulsified pre-emulsion prepared in S2 was transferred into a three-necked flask, and after slowly heating to 80°C under a N2 atmosphere, 0.08 g of initiator azobisisobutylamidine hydrochloride was dissolved in 8 ml of aqueous solution and injected into the reaction system at a uniform rate of 130 μl / min through a microinjection pump to initiate the reaction. After the initiator was added dropwise for 65 minutes, the reaction was continued at a temperature of 5 hours, and then the reaction was stopped and cooled to room temperature to obtain the fine emulsion (solid content 24.8%).

[0064] Example 4

[0065] A method for preparing a short-chain fluorinated polyacrylate three-proof finishing agent for cotton, the specific steps of the method are:

[0066] S1, pre-emulsification process:

[0067] 0.48g of hexadecyltrimethylammonium bromide and 0.16g of fatty alcohol polyoxyethylene ether AEO-9 were mixed and dissolved in 20ml of deionized water, and fully dissolved under stirring. 4g of perfluorohexylethyl acrylate, 2g of hexadecyl acrylate, 0.5g of methyl methacrylate, and 1.5g of butyl acrylate were taken, mixed evenly, and then dripped into the emulsifier aqueous solution drop by drop with a dropper within 15-20min, and stirred at 700r / min for 40min to form a pre-emulsion;

[0068] Polymerization monomer formula: 50% perfluorohexylethyl acrylate, 25% hexadecyl acrylate, 6.25% methyl methacrylate, and 18.75% butyl acrylate.

[0069] S2, fine emulsification process:

[0070] The pre-emulsion prepared in S1 was ultrasonically dispersed for 8 min by an ultrasonic cell crusher (power 270 w) under ice bath to form a fine emulsion pre-emulsion;

[0071] S3, aggregation process:

[0072] The fine emulsified pre-emulsion prepared in S2 was transferred into a three-necked flask, and after slowly heating to 70°C under a N2 atmosphere, 0.032 g of initiator azobisisobutylimidazoline hydrochloride was dissolved in 3 ml of aqueous solution and injected into the reaction system at a uniform rate of 110 μl / min through a microinjection pump to initiate the reaction. After the initiator was added dropwise for 75 minutes, the reaction was continued at a temperature of 5 hours, and then the reaction was stopped and cooled to room temperature to obtain the fine emulsion (solid content 25.4%).

[0073] Example 5

[0074] A preparation method of a short-chain fluorinated polyacrylate three-proof finishing agent for cotton, and the specific steps of the method are as follows:

[0075] S1, pre-emulsification process:

[0076] Dissolve 0.48 g of cetyltrimethylammonium bromide and 0.16 g of fatty alcohol polyoxyethylene ether AEO-9 in 20 ml of deionized water, and stir to fully dissolve it. Take 4 g of perfluorohexylethyl acrylate, 2 g of octadecyl acrylate, 0.44 g of methyl methacrylate, 1.32 g of butyl acrylate, and 0.24 g of glycidyl methacrylate. After mixing evenly, dropwise add it into the emulsifier aqueous solution with a dropper within 15 - 20 min, and stir at 700 r / min for 40 min to form a pre-emulsion;

[0077] Polymerization monomer formula: 50% of perfluorohexylethyl acrylate, 25% of octadecyl acrylate, 5.5% of methyl methacrylate, 16.5% of butyl acrylate, and 3% of glycidyl methacrylate.

[0078] S2, fine emulsification process:

[0079] Ultrasonically disperse the pre-emulsion prepared in S1 in an ice bath through an ultrasonic cell disruptor (power 300 w) for 6 min to form a fine emulsified pre-emulsion;

[0080] S3, polymerization process:

[0081] Transfer the fine emulsified pre-emulsion prepared in S2 into a three-necked flask. After slowly heating to 75 °C under a N2 atmosphere, dissolve 0.04 g of initiator 2,2'-azobis(2-methylpropionamidine) dihydrochloride in 4 ml of aqueous solution and inject it into the reaction system at a constant speed of 120 μl / min through a micro-injection pump to initiate the reaction. After the initiator is added dropwise for 70 min, continue the heat preservation reaction for 5 h, and then stop the reaction and cool to room temperature to obtain the fine emulsion (solid content 25.3%).

[0082] Example 6

[0083] A preparation method of a short-chain fluorinated polyacrylate three-proof finishing agent for cotton, and the specific steps of the method are as follows:

[0084] S1, pre-emulsification process:

[0085] Dissolve 0.48 g of cetyltrimethylammonium bromide and 0.16 g of fatty alcohol polyoxyethylene ether AEO-9 after compounding in 20 ml of deionized water, and stir to dissolve it completely. Take 4 g of perfluorohexylethyl acrylate, 2 g of octadecyl acrylate, 0.44 g of methyl methacrylate, 1.32 g of butyl acrylate, and 0.24 g of hydroxyethyl acrylate. After mixing evenly, use a dropper to drop it into the emulsifier aqueous solution drop by drop within 15 - 20 min, and stir at 700 r / min for 40 min to form a pre-emulsion;

[0086] Polymerization monomer formula: 50% of perfluorohexylethyl acrylate, 25% of octadecyl acrylate, 5.5% of methyl methacrylate, 16.5% of butyl acrylate, 3% of hydroxyethyl acrylate.

[0087] S2, fine emulsification process:

[0088] Ultrasonically disperse the pre-emulsion prepared in S1 in an ice bath through an ultrasonic cell disrupter (power 270 w) for 8 min to form a fine emulsified pre-emulsion;

[0089] S3, polymerization process:

[0090] Transfer the fine emulsified pre-emulsion prepared in S2 into a three-necked flask. After slowly heating to 80 °C under a N2 atmosphere, dissolve 0.048 g of initiator 2,2'-azobis(2-methylpropionamidine) dihydrochloride in 5 ml of aqueous solution and inject it into the reaction system at a constant speed of 140 μl / min through a micro-injection pump to initiate the reaction. After the initiator is added dropwise for 60 min, continue the insulation reaction for 5 h, and then stop the reaction and cool to room temperature to obtain the fine emulsion (solid content 25.5%).

[0091] Example

[0092] 1. Selection of emulsifier

[0093] To investigate the effect of the emulsifier on the properties of the emulsion, under the test conditions of the initiator AIBA dosage being 1% of the total monomer mass, the reaction temperature being 75 °C, the reaction time being 5 h, and the monomer formula (total 100%): the C6F content being 50%, the SA content being 25%, and the content of other functional acrylate monomers (MMA:BA being 1:1) being 25%, investigate the changes in the ratio of AEO-9:CTAB in the emulsifier and the amount of emulsifier used. The results are shown in Tables 1 and 2.

[0094] Table 1 Effect of emulsifier ratio on emulsion properties

[0095]

[0096] Table 2 Effect of emulsifier amount on emulsion properties

[0097]

[0098] As can be seen from Tables 1 and 2, with the increase in the dosage of cationic emulsifier CTAB, both the conversion rate and stability of the emulsion increase, the amount of gel decreases; when the ratio reaches 1:3, the emulsion prepared has the best stability, the highest conversion rate, and the least gel; with the increase in the dosage of the compound emulsifier, the conversion rate of the emulsion increases. When the dosage of the compound emulsifier increases to 8%, the conversion rate reaches the maximum value. Continuing to increase the dosage of the emulsifier will instead affect the emulsion performance. Therefore, it is preferred that AEO-9:CTAB = 1:3 and the dosage of the compound emulsifier is 8%.

[0099] 2. Investigation of the dosage of perfluorohexylethyl acrylate C6F

[0100] Under the experimental conditions of the compound emulsifier AEO-9:CTAB being 1:3, the dosage being 8% of the total mass of the monomers, the dosage of initiator AIBA being 1% of the total mass of the monomers, the reaction temperature being 75 °C, the reaction time being 5 h, and the monomer formulation (total 100%): the content of C6F being a variable, the content of SA being 25%, and the balance being other functional acrylate monomers (MMA:BA being 1:1), the optimal dosage of perfluorohexylethyl acrylate (C6F) was investigated. The results are shown in Table 3.

[0101] Table 3 Static contact angles and surface free energies of polymer films with different C6F monomer contents for water and diiodomethane

[0102]

[0103] As can be seen from Table 3, with the increase in the dosage of C6F, the surface energy of the latex film shows a decreasing trend. When the dosage of the fluorine monomer reaches 50%, the film contact angle is the largest and the surface energy drops to the lowest 9.16 mN·m -1 , when the fluorine content exceeds 50%, the surface energy does not tend to balance but instead increases slightly. At the same time, the price of the fluorine monomer is relatively high, and too high a dosage of the fluorine monomer will increase the production cost. Therefore, it is preferred that the dosage of the fluorine-containing monomer C6F is 50%.

[0104] 3. Polymer films with different octadecyl acrylate SA contents

[0105] Under the experimental conditions of the compound emulsifier AEO-9:CTAB being 1:3, the dosage being 8% of the total mass of the monomers, the dosage of initiator AIBA being 1% of the total mass of the monomers, the reaction temperature being 75 °C, the reaction time being 5 h, and the monomer formulation (total 100%): the content of C6F being 50%, the content of SA being a variable, and the balance being other functional acrylate monomers (MMA:BA being 1:1), the dosage of octadecyl acrylate (SA) was investigated. The results are shown in Table 4.

[0106] Table 4 Static contact angles and surface free energies of polymer films with different SA contents with respect to water and diiodomethane

[0107]

[0108]

[0109] As can be seen from Table 4, with the increase in the dosage of SA, the contact angle of the latex film with water shows an increasing trend, while the surface energy shows a decreasing trend. This is because SA and C6F have a synergistic effect, which improves the crystallinity of C6F, causing it to migrate to the surface. When C6F:SA (w / w) = 2:1, the conversion rate approaches equilibrium and the surface energy reaches the lowest. Therefore, the preferred dosage of SA is 25%.

[0110] 4. Influence of the weight ratio of methyl methacrylate MMA and butyl acrylate BA on the emulsion properties

[0111] Under the test conditions of the emulsifier blend AEO-9:CTAB being 1:3, the dosage being 8% of the total monomer mass, the initiator AIBA dosage being 1% of the total monomer mass, the reaction temperature being 75 °C, the reaction time being 5 h, and the monomer formulation (total 100%): the C6F content being 50%, the SA content being 25%, and the content of other functional acrylate monomers (the mass ratio of MMA and BA being a variable) being 25%, the influence of the weight ratio of methyl methacrylate MMA and butyl acrylate BA on the emulsion properties was investigated, and the results are shown in Table 5.

[0112] Table 5 Influence of MMA:BA on the emulsion properties

[0113]

[0114] As can be seen from Table 5, when the dosage of BA increases, the emulsion conversion rate gradually increases, the emulsion stability is enhanced, and the film-forming property is better. This is because the molecular chain of BA has high flexibility. Therefore, after adding BA during synthesis, the flexibility of the polymer molecular chain obtained is enhanced, and the latex film is relatively soft. Therefore, the preferred MMA:BA = 1:3.

[0115] 5. Influence of the dosage of glycidyl methacrylate GMA on the emulsion properties

[0116] Under the experimental conditions where the emulsifier blend is AEO-9:CTAB at a ratio of 1:3, the dosage is 8% of the total monomer mass, the dosage of initiator AIBA is 1% of the total monomer mass, the reaction temperature is 75 °C, the reaction time is 5 h, and the monomer formulation (total 100%): the C6F content is 50%, the SA content is 25%, and the content of other functional acrylate monomers (the variable GMA is investigated, and the balance is MMA and BA, with the mass ratio of MMA:BA being 1:3) is 25%, the effect of the dosage of glycidyl methacrylate GMA on the emulsion properties was investigated, and the results are shown in Table 6.

[0117] Table 6 Effect of GMA Dosage on Emulsion Properties

[0118]

[0119] As can be seen from Table 6, the GMA dosage has little effect on the emulsion conversion rate. With the increase in the GMA dosage, the particle size of the emulsion first decreases and then increases, and the contact angle of the latex film first increases and then decreases. When the GMA dosage is 3%, the particle size reaches the minimum value of 100.3 nm, and the film contact angle reaches the maximum value of 117.6°. Therefore, the preferred GMA dosage is 3%.

[0120] 6. Influence of Finishing Process on Contact Angle and Whiteness of Cotton Fabric

[0121] Using the padding and curing method, the influence of changes in finishing process parameters on the contact angle and whiteness of cotton fabric was investigated, and the results are as Figure 1 shown.

[0122] From Figure 1 it can be seen that through the single-factor analysis method, the influence of various finishing parameters on the cotton contact angle and whiteness was explored, and the optimal finishing process was obtained: impregnation for 15 min, finishing liquor concentration of 60 g / l, curing at 170 °C for 4 min. The water contact angle of the cotton fabric reached 151.2°, and the olive oil contact angle reached 140.6°.

[0123] 7. Morphology and Structure of Finished Cotton Fabric

[0124] The miniemulsion prepared in Example 5 was finished on cotton fabric, and its surface structure was observed by SEM. The results obtained are shown in Figure 2 .

[0125] From Figure 2 it can be seen that the surface of the raw cotton is rough and the grooves are obvious; after finishing, the fluoropolymer on the fabric surface is significantly cross-linked, and the cross-linking between the grooves is obvious, and the surface becomes smooth. This indicates that the finishing agent has been well finished on the cotton fabric and a smooth film has been formed on its surface.

[0126] Application Example

[0127] The miniemulsions prepared in the above Examples 1-6 were used as the three-proof finishing liquor and applied to cotton fabrics to prepare three-proof finished cotton fabrics. The specific steps of this method are as follows:

[0128] The pretreated cotton fabric (thoroughly cleaned before finishing) was soaked in the finishing liquor with a concentration of 50 g / l for 20 min, padded by a padding mangle in a one-dip-one-roll manner (pick-up rate: 70%-80%), the padded cotton fabric was pre-dried at 80 °C for 4 min, and then cured at 170 °C for 4 min to obtain the three-proof finished cotton fabric.

[0129] The water, oil and stain resistance properties of the finished cotton fabric were tested. The specific test methods are as follows:

[0130] (1) Static contact angle test

[0131] Using water (4 μl) and olive oil (0.5 μl) as the test liquids, the static contact angles of cotton were measured by a German Kruess DSA 20 type optical contact angle measuring instrument. Each sample was measured 5 times at different positions, and the average value was taken.

[0132] (2) Waterproof grade test

[0133] According to the test method of GB / T 4745-2012, the finished fabric was first cut into a cloth sample of 18 cm × 18 cm, 250 mL of test water was poured into the funnel, and it was continuously sprayed for 25-30 s. After the spraying was completed, the fabric was rated according to the wetting situation of the cotton fabric surface by water.

[0134] (3) Oil-proof grade test

[0135] The test was carried out according to the test method of GB / T 19977-2014. Eight kinds of oils with different surface tensions were dropped on the treated fabric. Observed at an angle of 45°, there was no obvious wetting phenomenon on the fabric within 30 s. The maximum grade of the test liquid that did not wet the fabric within 30 s was the oil repellency grade of the fabric.

[0136] (4) Stain resistance grade test

[0137] According to the test method of GB / T 30159.1-2013, two layers of filter paper were placed on a smooth horizontal surface, and then the test specimen was placed flat on the filter paper with the front side facing up. About 0.05 ml of dark soy sauce was dropped at three positions of the test specimen with a dropper, and the distance between each liquid drop was at least 50 mm, and the dropper mouth was about 6 mm away from the surface of the test specimen. After the test specimen was left standing for 30 s, the wetting situation of the liquid drops was observed at an angle of 45° for rating.

[0138] The comparison results of the three-proof properties of the short-chain fluorinated polyacrylate three-proof finishing agent prepared in each embodiment and the commercially available C6 waterproof finishing agent TG-5601 and the fluorine-free waterproof agent XF-5001 (purchased from Suzhou Heming Textile Auxiliary Agent Co., Ltd.) are shown in Table 7.

[0139] Table 7

[0140]

[0141]

[0142] Washing process: Wash 10 times at room temperature, 12 minutes / cycle → add detergent + wash cloth → wash 3 times with clean water → dry at 66℃ → regain moisture → test performance

[0143] After washing 10 times at room temperature, the detection results are shown in Table 8.

[0144] Table 8

[0145] Sample Water / ° Olive oil / ° Waterproof rating Oil-proof rating Stain resistance rating Example 1 142.3 130.8 3-4 4 5 Example 2 133.6 125.3 3 5 4 Example 3 137.4 124.8 3 4 4 Example 4 135.2 125.2 3 4 4 Example 5 143.5 132.6 4-5 4 5 Example 6 141.2 130.8 4-5 4 5 TG-5601 144.2 132.6 4-5 5 5 XF-5001 130.8 65.3 2-3 1 2

[0146] It can be seen from Tables 7 and 8 that the cotton fabrics treated with the short-chain fluorinated polyacrylate three-proof finishing agent prepared in Examples 1-6 have excellent water-proof, oil-proof and stain-resistant properties and have certain water-washing resistance. The water-proof and stain-resistant levels are comparable to those of the C6 waterproof finishing agent TG-5601 on the market, the oil-proof level is slightly lower, and the three-proof performance is better than that of the fluorine-free waterproof agent XF-5001.

[0147] By comparing Example 1, Example 2, Example 3 and Example 4, it can be seen that the introduction of long-chain monomers will produce a synergistic effect with C6F, further enhancing the waterproof effect of cotton fabrics, and the effect of octadecyl acrylate is slightly better than that of hexadecyl acrylate, but excessive SA may cover the short chain of C6F and affect its effect. At the same time, the introduction of SA reduces the amount of C6F used and reduces the cost.

[0148] By comparing Example 1, Example 5 and Example 6, it can be seen that the introduction of the cross-linking monomer can enhance the stability of the emulsion and improve the water-washing resistance of the cotton fabric.

[0149] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0150] The above has introduced in detail the short-chain fluorinated polyacrylate three-proof finishing agent for cotton, its preparation method and its application. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A preparation method of a short-chain fluorinated polyacrylate three-proof finishing agent for cotton, characterized in that The method comprises the following steps: S1, pre-emulsification process: Cetyltrimethylammonium bromide (CTAB) and alcohol polyoxyethylene ether (AEO-9) are compounded in a mass ratio of 3:1 and dissolved in water. Under stirring, they are fully dissolved to obtain an emulsifier aqueous solution. The sum of the dosages of CTAB and AEO-9 accounts for 8% of the total mass of the monomers. Perfluorohexylethyl acrylate, octadecyl acrylate and functional acrylate monomers are taken, mixed evenly and then dropped into the emulsifier aqueous solution drop by drop within 15 - 20 min. Under vigorous stirring at 500 - 800 r / min, they are stirred for 30 - 50 min to form a pre-emulsion. Among them, perfluorohexylethyl acrylate accounts for 50% of the total mass of the monomers, octadecyl acrylate accounts for 25% of the total mass of the monomers, the functional acrylate monomers are a mixture of methyl methacrylate, butyl acrylate and glycidyl methacrylate, accounting for 25% of the total mass of the monomers, and glycidyl methacrylate accounts for 2 - 4% of the total mass of the monomers. S2, fine emulsification process: The pre-emulsion prepared in S1 is ultrasonically dispersed in an ice bath by an ultrasonic cell disruptor with a power of 200 - 400 w for 5 - 15 min to form a fine emulsified pre-emulsion. S3, polymerization process: The fine emulsified pre-emulsion prepared in S2 is slowly heated to the reaction temperature of 60 - 80 °C in an N2 atmosphere; an aqueous initiator solution is uniformly injected into the reaction system through a micro-injection pump to initiate the reaction. After the initiator is completely added dropwise, the reaction is continued to be kept warm for 3 - 6 h, and then the reaction is stopped and cooled to room temperature. The obtained fine emulsion is a short-chain fluorinated polyacrylate three-proof finishing agent for cotton. The initiator is azodiisobutylamidine hydrochloride or azodiisobutyramidine hydrochloride, and its dosage accounts for 0.2% - 1% of the total mass of the monomers; the injection rate of the micro-injection pump is 100 μl / min - 140 μl / min, and the injection time is 60 - 80 min.

2. A short-chain fluorinated polyacrylate three-proof finishing agent for cotton obtained by the preparation method described in claim 1.

3. A three-proof finishing method for cotton fabrics, characterized in that The method includes the following steps: The pretreated cotton fabric is soaked in an aqueous solution of the three-proof finishing agent described in claim 2 with a concentration of 50 g / l for 20 min, and is padded by a padding mangle in a one-dip-one-roll manner with a liquor pickup of 70% - 80%. The padded cotton fabric is pre-dried at 80 °C for 4 min, and then baked at 170 °C for 4 min to obtain a three-proof finished cotton fabric.

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