A fabric darkening agent and preparation method thereof

Abstract

The present invention discloses a deepening agent and a preparation method thereof. The deepening agent of the present invention is prepared from the following raw materials: 5-15 mass% of PU prepolymer, 10-20 mass% of organosilicon chain extender, 0.2-4 mass% of hydroxyalkyl (meth) acrylate, 10-20 mass% of perfluoroalkyl alkyl (meth) acrylate, 1-4 mass% of triacrylate monomer, 2-10 mass% of emulsifier, 40-70 mass% of deionized water, with the total mass of the above raw materials being 100 mass%. The deepening agent prepared by the present invention has good deepening effect, is non-selective to fabrics and dyes, has wide adaptability, and the fabric treated by the deepening agent is washable, and the deepening effect does not decrease during natural placement.

Description

Technical Field

[0001] The present invention relates to the field of functional fabric finishing agents, in particular to a method for preparing a fabric darkening agent. Background Art

[0002] Darkening treatment of textiles means deepening the color of the fabric without increasing the amount of dye, saving dyes, reducing production costs, and reducing the content of colored substances in printing and dyeing wastewater. One of the most commonly used methods is to attach a darkening agent to the surface of the fabric through post-finishing to achieve a darkening effect on the dyed fabric.

[0003] Experts and scholars at home and abroad have conducted extensive research on the preparation of polyester fabric darkening agents. Through various methods, low-refractive-index polymer substances that can form thin films on the fabric surface have been prepared, such as fluorine-containing resins, silicone resins, polyurethane resins, acrylic resins, etc. Among them, silicone resins are soft and low-priced, with good overall performance and application prospects, but their darkening performance is not as good as organic fluorine resins. Fluororesins have a low refractive index and good darkening effect, but they are expensive and have high costs. Acrylic substances have a good darkening effect, but the fabric properties are easily affected after treatment, such as the hardening of the feel. Polyurethane resins are hand-friendly, but the darkening effect is average. Therefore, the development trend of darkening agents is to combine several resins to improve the overall performance of darkening agents. For example, the patent application number 201510313509.6, “A core-shell structure emulsion darkening agent for polyester fabrics and its preparation method”, prepares a polyacrylate-polysiloxane core-shell structure emulsion, which is used as a polyester fabric darkening agent. The polyester fabric treated with it has a small color difference and little effect on fastness, but the darkening rate is less than 30%, and the darkening effect is general; there is another patent application number 201310713917.1, “A preparation method for an environmentally friendly fabric darkening agent”, which prepares a silicone-fluorine-acrylate copolymer, which achieves the purpose of enhancing the color depth of the fabric, reducing color change, improving the feel and environmental protection. However, due to the characteristics of acrylic resin being hot-sticky and cold-brittle and having poor weather resistance, the fabric treated with it has poor wearing performance.

[0004] Most commercially available darkening agents have excellent darkening properties for chemical fibers like polyester, but poor darkening properties for natural fibers like cotton. They also exhibit dye selectivity, poor adaptability, significant degradation of darkening properties over time, and poor weather resistance. Therefore, developing darkening agents with excellent darkening properties, no selectivity for fabrics and dyes, broad adaptability, washability, and no degradation of darkening effects during natural storage is extremely valuable. Summary of the Invention

[0005] One aspect of the present invention provides a darkening agent, which is prepared from the following raw materials:

[0006]

[0007] The total mass of the above raw materials is taken as 100 mass %.

[0008] Another aspect of the present invention provides a method for preparing a darkening agent, the method comprising the following steps:

[0009] 1) Adding an organosilicon chain extender to the PU prepolymer at 60-80°C in the presence of a solvent and a catalyst to carry out a chain extension reaction;

[0010] 2) adding hydroxyalkyl (meth)acrylate at 60-80° C. to carry out end-capping reaction;

[0011] 3) adding perfluoroalkylalkyl (meth)acrylate, triacrylate monomer, emulsifier and deionized water to step 2), stirring and emulsifying at 40-60° C. for 1-2 hours;

[0012] 4) Raise the temperature to 60-80°C and add a peroxide polymerization initiator aqueous solution dropwise to initiate the polymerization reaction;

[0013] 5) Raise the temperature to 75-90°C and keep warm for 1-5 hours to obtain the darkening agent.

[0014] The darkening agent of the invention has good darkening performance, is non-selective to fabrics and dyes, and has wide adaptability. The fabric darkened by the agent is washable, and the darkening effect does not decrease during natural placement. DETAILED DESCRIPTION

[0015] In a preferred embodiment of the present invention, a darkening agent is provided, which is prepared from the following raw materials:

[0016]

[0017] The total mass of the above raw materials is taken as 100 mass %.

[0018] Preferably, it is prepared from the following raw materials:

[0019]

[0020] The total mass of the above raw materials is taken as 100 mass %.

[0021] Preferably, the PU prepolymer is a waterborne polyurethane prepolymer with an -NCO content of 10% to 30%.

[0022] Preferably, the organosilicon chain extender is a hydroxy silicone oil represented by formula I:

[0023]

[0024] In Formula 1:

[0025] n is an integer from 2 to 30.

[0026] Preferably, the hydroxyalkyl (meth)acrylate is a hydroxy C1-5 alkyl (meth)acrylate.

[0027] Preferably, the perfluoroalkylalkyl (meth)acrylate is a compound represented by formula II:

[0028]

[0029] In Formula II:

[0030] R1 is H or CH3;

[0031] m is an integer from 1 to 10;

[0032] Rf is C 1-6 Perfluoroalkyl.

[0033] Preferably, the triacrylate monomer is one or more of glycerol trihydroxypropyl ether triacrylate and trimethylol propane triacrylate.

[0034] Preferably, the emulsifier is one or more of fatty alcohol polyoxyethylene ether, dodecyldimethylbenzyl ammonium chloride, octadecyltrimethylammonium chloride, and hexadecyltrimethylammonium chloride.

[0035] Preferably, the weight average molecular weight of the darkening agent is 30,000-150,000.

[0036] According to another preferred embodiment of the present invention, a method for preparing a darkening agent is provided, the method comprising the following steps:

[0037] 1) adding 10-20% by mass of an organosilicon chain extender to 5-15% by mass of a PU prepolymer at 60-80° C. in the presence of a solvent and a catalyst to carry out a chain extension reaction;

[0038] 2) adding 0.2-4% by mass of hydroxyalkyl (meth)acrylate at 60-80° C. to carry out end-capping reaction;

[0039] 3) adding 10-20 mass % of perfluoroalkylalkyl (meth)acrylate, 1-4 mass % of triacrylate monomer, 2-10 mass % of emulsifier and 40-70 mass % of deionized water to step 2), stirring and emulsifying at 40-60° C. for 1-2 hours;

[0040] 4) Raise the temperature to 60-80°C and add a peroxide polymerization initiator aqueous solution dropwise to initiate the polymerization reaction;

[0041] 5) Raise the temperature to 75-90°C and keep warm for 1-5 hours to obtain the darkening agent.

[0042] Preferably, the preparation method of the darkening agent of the present invention comprises the following steps:

[0043] 1) adding 12-16% by mass of an organosilicon chain extender to 6-10% by mass of a PU prepolymer at 65-75° C. in the presence of a solvent and a catalyst to carry out a chain extension reaction;

[0044] 2) adding 0.5-2% by mass of hydroxyalkyl (meth)acrylate at 65-75° C. to carry out end-capping reaction;

[0045] 3) adding 12-16 mass % of perfluoroalkylalkyl (meth)acrylate, 1.5-3.5 mass % of triacrylate monomer, 4-7 mass % of emulsifier and 50-60 mass % of deionized water to step 2), stirring and emulsifying at 40-60° C. for 1-2 hours;

[0046] 4) Raise the temperature to 60-80°C and add aqueous ammonium persulfate solution dropwise to initiate polymerization;

[0047] 5) Raise the temperature to 75-90°C and keep warm for 2-3 hours to obtain the darkening agent.

[0048] Preferably, the solvent includes N-methylpyrrolidone, and the catalyst is an organic bismuth catalyst.

[0049] Preferably, the aqueous ammonium persulfate solution in the present invention is 0.5% ammonium persulfate (10% aqueous solution) in the entire system.

[0050] Compared with the preparation methods of the currently disclosed darkening agents, the originality of this invention is reflected in the following aspects: (1) The present invention adopts an organic silicone chain extender, which has both darkening performance and soft feel; (2) The perfluoroalkyl alkyl (meth)acrylate is introduced to further enhance the darkening effect; (3) The polyurethane and polyacrylate structures complement each other, improving film-forming properties while also having flexibility and weather resistance; (4) The introduction of triacrylate monomers enhances the cross-linking density, improves the continuity and density of the film formed by the darkening agent on the fabric surface, and improves the washability and durability.

[0051] The product of the invention has good darkening performance, is non-selective to fabrics and dyes, and has wide adaptability. The fabric darkened by the product is washable, and the darkening effect is well retained during natural placement.

[0052] Example

[0053] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0054] In each embodiment, all base materials and fabrics are commercially available. Unless otherwise specified, % is % by weight.

[0055] The performance of the product and its application process and performance on textiles are measured as follows:

[0056] (1) Product performance

[0057] (1) Weight-average molecular weight determination: The weight-average molecular weight was determined using a HLC-8320GPC gel permeation chromatograph (Tosoh Corporation, Japan). The mobile phase was DMF at 25°C, and polymethyl methacrylate (PMMA) was used as a reference.

[0058] (2) Stability:

[0059] a. Centrifugal stability: Centrifuge at 3000 r / min for 30 minutes and observe whether there is oil floating, stratification or precipitation. If so, it is judged as unstable; otherwise, it is judged as stable.

[0060] b. Electrolyte resistance stability: Prepare 200 mL of 20 g / L darkening agent with tap water, add 15 g / L sodium carbonate and 15 g / L sodium sulfate, and observe whether oil floating, stratification or precipitation occurs. If so, it is judged to be unstable; otherwise, it is judged to be stable.

[0061] c. Acid resistance stability: Prepare 200 mL of 20 g / L darkening agent with tap water, add 0.1 mol / L hydrochloric acid solution, and observe whether oil floating, stratification or precipitation occurs. If so, it is judged to be unstable; otherwise, it is judged to be stable.

[0062] d. Alkali resistance and stability: Prepare 200 mL of 20 g / L darkening agent with tap water, add 10 g / L of sodium hydroxide, shake and keep warm at 98°C for 30 minutes, and observe whether there is oil floating, stratification or precipitation. If so, it is judged as unstable; otherwise, it is judged as stable.

[0063] (2) Application technology and performance on textiles

[0064] 1. Application technology of textiles:

[0065] Samples: (red, black, navy) polyester knitted fabric, (red, black, turquoise) cotton knitted fabric

[0066] Formula: Darkening agent 30g / L

[0067] Darkening finishing process:

[0068] Dip and roll → Dry (170℃×60s)

[0069] 2. Fabric performance determination:

[0070] Darkening Performance: Test the fabric's strength using a Datacolor colorimeter. Use the original fabric as the standard, with the strength set at 100. Compare the strength of the darkening-treated fabric to the standard. The greater the strength, the better the darkening performance.

[0071] Hand feel: Five trained people evaluated the hand feel of the fabric and gave a score of 1-5, with 1 being the worst and 5 being the best, and then took the average value.

[0072] Washing method: Wash according to AATCC-135 standard.

[0073] Example 1

[0074] Aqueous polyurethane prepolymer Aquolin161 (purchased from Wanhua Chemical Group Co., Ltd., -NCO content 18-19%) 10g was added to a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser. The temperature was raised to 70°C, and N-methylpyrrolidone accounting for 1.5% of the total system and bismuth neodecanoate catalyst DY-20 accounting for 0.12% of the total system were added (purchased from Shanghai Deyin Chemical Co., Ltd.). 13.5g of hydroxy silicone oil (n is 10) was added dropwise. After the addition was completed, the temperature was kept for 1.5 hours, and then hydroxyethyl acrylate was added. 1.3g, continue to keep warm for 1 hour, then cool to 50°C, add 13g of perfluorohexyl ethyl acrylate, 2g of glycerol trihydroxypropyl ether triacrylate, 3g of dodecyldimethylbenzyl ammonium chloride, 3g of fatty alcohol polyoxyethylene ether O-15 (EO number is 15, purchased from Hai'an Petrochemical Plant in Jiangsu Province) and 54.2g of deionized water, stir and emulsify for 1.5 hours, heat to 70°C, add ammonium persulfate (10% aqueous solution) in an amount of 0.5% of the total system, and after the addition is complete, heat to 80°C and keep warm for 2.5 hours to prepare the darkening agent 1. The weight average molecular weight of the darkening agent 1 is 41500.

[0075] Example 2

[0076] Aqueous polyurethane prepolymer Aquolin278 (purchased from Wanhua Chemical Group Co., Ltd., -NCO content 21-22%) 7g was added to a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser. The temperature was raised to 65°C, and N-methylpyrrolidone accounting for 1.5% of the total system and bismuth neodecanoate catalyst DY-20 accounting for 0.12% of the total system were added (purchased from Shanghai Deyin Chemical Co., Ltd.). 14g of hydroxy silicone oil (n is 16) was added dropwise. After the addition was completed, the mixture was kept warm for 2 hours, and then 1.75g ​​of hydroxyethyl acrylate was added and the mixture was kept warm for 1 hour. , then cool to 50°C, add 15g of 2,2,2-trifluoroethyl methacrylate, 3g of trimethylolpropane triacrylate, 3g of octadecyltrimethylammonium chloride, 2g of fatty alcohol polyoxyethylene ether O-15 (EO number is 15, purchased from Hai'an Petrochemical Plant in Jiangsu Province) and 54.25g of deionized water, stir and emulsify for 1.5 hours, heat to 70°C, add 0.5% of ammonium persulfate (10% aqueous solution) in the whole system, after the addition is completed, heat to 85°C, keep warm for 2 hours, and prepare the darkening agent 2. The weight average molecular weight of the darkening agent 2 is 97800.

[0077] Example 3

[0078] 8 g of waterborne polyurethane prepolymer Aquolin 270 (purchased from Wanhua Chemical Group Co., Ltd., -NCO content 20.2-21.2%) was added to a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser. The temperature was raised to 75° C., 1.5% of N-methylpyrrolidone and 0.12% of bismuth neodecanoate catalyst DY-20 (purchased from Shanghai Deyin Chemical Co., Ltd.) were added, and 13.5 g of hydroxy silicone oil (n is 10) was added dropwise. After the addition was completed, the mixture was kept warm for 1.5 hours, and then 0.65 g of hydroxyethyl acrylate was added. The mixture was kept warm for 1 hour, then cooled to 50° C., and 15 g of perfluorohexylethyl acrylate, 1 g of glycerol trihydroxypropyl ether triacrylate, 1.5 g of trimethylol propane triacrylate, 3 g of hexadecyltrimethylammonium chloride, 3 g of fatty alcohol polyoxyethylene ether O-20 (EO number 20, purchased from Hai'an Petrochemical Plant in Jiangsu Province) and 54.35 g of deionized water were added. The mixture was stirred and emulsified for 1.5 hours, and the temperature was raised to 70° C. Ammonium persulfate (10% aqueous solution) accounting for 0.5% of the total system was added dropwise. After the addition was completed, the temperature was raised to 80° C. and kept warm for 2.5 hours to obtain the darkening agent 3. The weight average molecular weight of the darkening agent 3 was 66200.

[0079] The stability and application performance of the products in each embodiment are shown in Table 1, Table 2, and Table 3.

[0080] Table 1 Stability

[0081] Centrifugal stability Electrolyte stability Acid stability Alkali resistance stability Example 1 Stablize Stablize Stablize Stablize Example 2 Stablize Stablize Stablize Stablize Example 3 Stablize Stablize Stablize Stablize

[0082] Table 2 Darkening effect of polyester fabric after treatment

[0083]

[0084] Table 3 Darkening effect of cotton fabric after treatment

[0085]

[0086] As can be seen from the table above, the present invention's darkening agent exhibits excellent stability. Fabrics treated with this darkening agent exhibit significant darkening effects, excellent wash resistance, and durability, whether on polyester or cotton fabrics. Especially on cotton fabrics, the darkening performance is even more pronounced compared to commercially available darkening agents.

Claims

1. A method for preparing a darkening agent, prepared from the following raw materials: Taking the total mass of the above raw materials as 100 mass %, The organosilicon chain extender is a hydroxy silicone oil represented by Formula I: In Formula I: n is an integer from 2 to 30, The perfluoroalkylalkyl (meth)acrylate is a compound represented by formula II: In Formula II: R1 is H or CH3; m is an integer from 1 to 10; Rf is C 1-6 Perfluoroalkyl, The method includes the following steps: 1) Adding an organosilicon chain extender to the PU prepolymer at 60-80°C, and carrying out a chain extension reaction in the presence of a solvent and a catalyst; 2) adding hydroxyalkyl (meth)acrylate at 60-80° C. to carry out end-capping reaction; 3) adding perfluoroalkylalkyl (meth)acrylate, triacrylate monomer, emulsifier and deionized water to the product of step 2), stirring and emulsifying at 40-60° C. for 1-2 hours; 4) Raise the temperature to 60-80°C, add a peroxide polymerization initiator aqueous solution dropwise to initiate the polymerization reaction; 5) Raise the temperature to 75-90°C and keep warm for 1-5 hours to obtain a darkening agent.

2. The method for preparing the darkening agent according to claim 1, characterized in that: Prepared from the following raw materials: The total mass of the above raw materials is taken as 100 mass %.

3. The method for preparing the darkening agent according to claim 1, characterized in that: The PU prepolymer is a water-based polyurethane prepolymer with an NCO content of 10% to 30%.

4. The method for preparing the darkening agent according to claim 1, characterized in that: The hydroxyalkyl (meth)acrylate is a hydroxy C1-5 alkyl (meth)acrylate.

5. The method for preparing the darkening agent according to claim 1, characterized in that: The triacrylate monomer is one or more of glycerol trihydroxypropyl ether triacrylate and trimethylol propane triacrylate.

6. The method for preparing the darkening agent according to claim 1, characterized in that: The emulsifier is one or more of fatty alcohol polyoxyethylene ether, dodecyl dimethyl benzyl ammonium chloride, octadecyl trimethyl ammonium chloride, and hexadecyl trimethyl ammonium chloride. The weight average molecular weight of the darkening agent is 30,000-150,000.

7. The method for preparing the darkening agent according to claim 1, characterized in that: The solvent is N-methylpyrrolidone, and the catalyst is an organic bismuth catalyst.

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