A method for flame retardant finishing of polyester / cotton blended fabric using wool dissolving liquid

Abstract

The invention belongs to the technical field of flame-retardant fabrics and relates to a method for flame-retardant finishing of polyester / cotton blended fabrics with a wool dissolving solution. The method specifically comprises the following steps: firstly treating the wool fabric with a tin tetrachloride solution, then treating the wool fabric with a disodium hydrogen phosphate solution, and then treating the wool fabric with a sodium silicate solution to obtain a wool dissolving solution, and finally treating the polyester / cotton blended fabric with the wool dissolving solution to obtain a flame-retardant polyester / cotton blended fabric with good flame-retardant performance and low smoke and heat release performance.

Description

Technical Field

[0001] The invention belongs to the technical field of flame-retardant fabrics, and in particular relates to a method for flame-retardant finishing of polyester / cotton blended fabrics using wool dissolving liquid. Background Art

[0002] Polyester / cotton blended fabric is a kind of fabric made by mixing polyester (polyester fiber) and cotton fiber in a certain proportion. This blend combines the advantages of polyester such as wear resistance, wrinkle resistance, high strength and good shape retention with the softness, breathability, moisture absorption and comfort of cotton fiber, making polyester / cotton blended fabric widely used in many fields such as clothing, home decoration, industrial products, etc. For example, in the field of clothing, it is often used to make casual wear, work clothes and some outdoor equipment; in the field of home furnishing, it is often used in curtains, bedding and sofa covers; in the industrial field, polyester / cotton blended fabric is also used to make protective clothing, filter materials, etc. due to its durability.

[0003] However, despite the superior performance and wide application of polyester / cotton blended fabrics, polyester and cotton fibers are flammable materials. Once they encounter a fire source, they will burn rapidly and may produce a large amount of smoke and toxic gases, posing a serious threat to people's lives and property. Especially in some occasions with extremely high fire protection requirements, such as firefighting clothing, hospital supplies, children's clothing, etc., the flame retardant properties of polyester / cotton blended fabrics are particularly important. Therefore, flame retardant treatment of polyester / cotton blended fabrics to improve their flame retardant properties is the key to ensure their safe use in specific fields. Unfortunately, the flame retardant treatment process faces considerable challenges. Polyester and cotton fibers will produce a "bracket effect" when burning, making the flammability of polyester / cotton blended fabrics much stronger than that of single fiber fabrics, which also brings greater difficulty to the flame retardant finishing of polyester / cotton blended fabrics.

[0004] The literature (Flame retardant finishing of polyester / cotton blended fabrics [J]. Printing and Dyeing, 2006, 32(11):1-5.) used cotton flame retardant CP, polyester flame retardant DFR and DFR / CP two-step method to finish polyester / cotton blended fabrics. However, regardless of whether the finishing is done alone or in combination, the flame retardant effect of the polyester / cotton blended fabrics is always unsatisfactory.

[0005] Reference (Durable flame retardant finishing process for polyester-cotton fabrics [J]. Printing and Dyeing, 2003, 29(2): 18-19.) uses a mixture of pure cotton durable flame retardant finishing agent FK-103 and polyester durable flame retardant finishing agent FK-106, and then uses resin finishing to achieve a flame retardant effect. However, the flame retardant effect cannot meet expectations and still needs to be further improved.

[0006] Therefore, it is necessary to propose a new method for flame retardant finishing of polyester / cotton blended fabrics to improve the flame retardant effect of polyester / cotton blended fabrics. Summary of the invention

[0007] The purpose of the present invention is to solve the above problems in the prior art and provide a method for flame retardant finishing of polyester / cotton blended fabrics using wool dissolving liquid.

[0008] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0009] A method for flame retardant finishing of polyester / cotton blended fabric using wool dissolving liquid comprises the following steps:

[0010] (1) Immerse the wool fabric in a tin tetrachloride solution at a temperature above 85°C;

[0011] In this process, tin tetrachloride hydrolyzes on the surface and inside of wool fibers to form poorly water-soluble tin hydroxide;

[0012] The treatment temperature is controlled to be above 85℃ in this stage because the surface of wool fiber is rich in scales. Raising the temperature helps to open the scales of wool fiber, so that tin tetrachloride can diffuse into the interior of wool fiber and be more evenly distributed on the wool macromolecular chain.

[0013] (2) immersing the wool fabric treated in step (1) in a disodium hydrogen phosphate solution at a temperature above 85° C.;

[0014] In this process, tin hydroxide reacts with the phosphate of disodium hydrogen phosphate to form basic tin phosphate;

[0015]

[0016] The treatment temperature is controlled to be above 85℃ in this stage because the surface of wool fiber is rich in scale layer. Raising the temperature helps to open the scale layer of wool fiber, so that disodium hydrogen phosphate can diffuse into the interior of wool fiber and react with tin hydroxide.

[0017] (3) immersing the wool fabric treated in step (2) in a sodium silicate solution at a temperature above 85° C. to obtain a wool solution;

[0018] During this process, the following reactions occur simultaneously:

[0019] Basic tin phosphate reacts with sodium silicate to form insoluble tin phosphate-silicate complex salt;

[0020] Sodium silicate hydrolyzes in aqueous solution to form an alkaline solution, which can react chemically with keratin in wool, destroying the hydrogen bonds and hydrophobic effects within the protein molecules, leading to the decomposition and dissolution of keratin;

[0021] Wool keratin is a macromolecular long-chain structure, rich in amino and carboxyl groups, and can form strong ionic bonds and chelate reactions with phosphates and tin metal salts in insoluble tin phosphate silicate complex salts, thus playing the role of dispersing insoluble tin phosphate silicate complex salts.

[0022]

[0023] The treatment temperature is controlled to be above 85℃ in this stage because the surface of wool fiber is rich in scale layer. Raising the temperature helps to open the scale layer of wool fiber, so that sodium silicate can diffuse into the interior of wool fiber and participate in the reaction.

[0024] (4) Using the wool solution obtained in step (3) as the main component or the entire component of the flame retardant finishing liquid, and using the flame retardant finishing liquid to finish the polyester / cotton blended fabric to obtain the flame retardant polyester / cotton blended fabric.

[0025] As the preferred technical solution:

[0026] In the method for flame retardant finishing of polyester / cotton blended fabric with wool dissolving liquid as described above, in steps (1) to (3), the treatment temperature range is 85-90°C and the treatment time range is 30-60 minutes.

[0027] In the method for flame retardant finishing of polyester / cotton blended fabric with wool solution as described above, in step (1), the concentration of tin tetrachloride solution is 4-10 g / L, and the mass ratio of wool fabric to tin tetrachloride solution is 1:30-40.

[0028] In the method for flame retardant finishing of polyester / cotton blended fabric with wool solution as described above, in step (2), the concentration of disodium hydrogen phosphate solution is 30-50 g / L, and the mass ratio of wool fabric to disodium hydrogen phosphate solution is 1:30-40.

[0029] In the method for flame retardant finishing of polyester / cotton blended fabric with wool solution as described above, in step (3), the concentration of sodium silicate solution is 20-40 g / L, and the mass ratio of wool fabric to sodium silicate solution is 1:30-40.

[0030] The method for flame retardant finishing of polyester / cotton blended fabric with wool dissolving solution as described above, in step (4), the flame retardant finishing solution is composed of sodium hypophosphite, citric acid and the wool dissolving solution obtained in step (3), the concentration of sodium hypophosphite is 15-20 g / L, the concentration of citric acid is 30-50 g / L, the sodium hypophosphite can promote the esterification cross-linking reaction between the carboxyl group of citric acid and the active group of wool keratin and the hydroxyl group of cotton fiber, and the content of polyester in the polyester / cotton blended fabric is 20-80wt%.

[0031] In the method for flame retardant finishing of polyester / cotton blended fabric with wool dissolving liquid as described above, in step (4), finishing is sequentially performed by double dipping and double rolling, pre-baking and baking, wherein the total duration of the double dipping and double rolling does not exceed 10 minutes, the rolling rate of the double dipping and double rolling is 90-100%, the pre-baking temperature is 60-70°C, the pre-baking time is 3-5 minutes, the baking temperature is 140-150°C, and the baking time is 3-5 minutes. The higher the baking temperature, the more helpful it is to promote the cross-linking of citric acid with the flame retardant and cotton fiber, but too high a temperature will cause greater damage to the physical properties of the fabric.

[0032] A method for flame retardant finishing of polyester / cotton blended fabric with wool dissolving solution as described in any of the above items, wherein the flame retardant polyester / cotton blended fabric has a limiting oxygen index of ≥30.2%, a damaged length of ≤9.8cm, and a total smoke release of ≤0.58m 2 , maximum heat release rate ≤275kW / m 2 , the residual carbon content is ≥10.5%; since the phosphate structure in the wool solution can act as an acid source and the wool keratin can act as a gas source and a carbon source, an intumescent flame retardant system can be constructed with a high carbonization efficiency, and tin metal salts and silicates are helpful in generating thermally stable residual carbon, thereby improving the thermal stability and residual carbon content of the residual carbon. Therefore, the flame retardant polyester / cotton blended fabric has excellent flame retardant properties and lower smoke and heat release properties.

[0033] Beneficial effects:

[0034] (1) The present invention uses tin tetrachloride, disodium hydrogen phosphate and sodium silicate to prepare a wool dissolving solution. The phosphate structure in the wool dissolving solution can serve as an acid source, and the wool keratin can serve as a gas source and a carbon source, so as to construct an intumescent flame retardant system with high carbonization efficiency. In addition, the tin metal salt and the silicate are helpful in generating thermally stable residual carbon, thereby improving the thermal stability and the amount of residual carbon. The flame retardant polyester / cotton blended fabric finished with the wool dissolving solution of the present invention has excellent flame retardant properties and lower smoke and heat release properties.

[0035] (2) The flame retardant system of the present invention efficiently utilizes wool keratin and is an environmentally friendly flame retardant system. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a picture of the flame-retardant polyester / cotton blended fabric prepared in Example 1 of the present invention after being subjected to a vertical burning test. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it 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 within the scope limited by the appended claims of the application equally.

[0038] Testing methods for relevant performance indicators:

[0039] Limiting oxygen index: measured with FTT0080 oxygen index meter according to GB / T 5454-1997;

[0040] Damage length: Tested in accordance with GB / T 5455-2014 using M233M vertical combustion test machine;

[0041] Total smoke release, maximum heat release rate, and carbon residue: tested using a VOUCH 6810 cone calorimeter in accordance with ISO 5660-1, with a radiation heat flux density of 35kW / m 2 The fabric size is 100mm × 100mm, and three layers of fabric are used for testing. The sample is weighed before the test, and the remaining material after thermal radiation treatment is weighed again to calculate the residual carbon content.

[0042] Example 1

[0043] A method for flame retardant finishing of polyester / cotton blended fabric using wool dissolving liquid, the specific steps are as follows:

[0044] (1) Prepare the raw materials:

[0045] wool fabric;

[0046] Tin tetrachloride solution: the solvent is water;

[0047] Disodium hydrogen phosphate solution: the solvent is water;

[0048] Sodium silicate solution: the solvent is water;

[0049] Sodium hypophosphite;

[0050] Citric acid;

[0051] Polyester / cotton blended fabric: polyester content is 20wt%, limiting oxygen index is 19.2%, damage length is 30cm, total smoke release is 0.71m 2 , the maximum heat release is 475kW / m 2 , the residual carbon content is 1.2%;

[0052] (2) Preparation of flame retardant finishing liquid:

[0053] (2.1) Immerse wool fabric in tin tetrachloride solution at 85°C for 60 min;

[0054] The concentration of the tin tetrachloride solution is 4 g / L, and the mass ratio of the wool fabric to the tin tetrachloride solution is 1:30;

[0055] (2.2) immersing the wool fabric treated in step (2.1) in a disodium hydrogen phosphate solution at 85° C. for 60 min;

[0056] The concentration of the disodium hydrogen phosphate solution is 30 g / L, and the mass ratio of the wool fabric to the disodium hydrogen phosphate solution is 1:30;

[0057] (2.3) immersing the wool fabric treated in step (2.2) in a sodium silicate solution at 85° C. for 60 minutes to obtain a wool solution;

[0058] The concentration of the sodium silicate solution is 20 g / L, and the mass ratio of the wool fabric to the sodium silicate solution is 1:30;

[0059] (2.4) uniformly mixing sodium hypophosphite, citric acid and the wool solution obtained in step (2.3) to obtain a flame retardant finishing solution;

[0060] In the flame retardant finishing liquid, the concentration of sodium hypophosphite is 15g / L and the concentration of citric acid is 30g / L;

[0061] (3) Flame retardant finishing of polyester / cotton blended fabrics:

[0062] The flame retardant polyester / cotton blended fabric is obtained by sequentially subjecting the polyester / cotton blended fabric to two-immersion and two-rolling, pre-baking and baking treatments;

[0063] Among them, the total time of the double immersion and double rolling is 10 minutes, the rolling rate of the double immersion and double rolling is 90%, the pre-baking temperature is 60°C, the pre-baking time is 5 minutes, the baking temperature is 140°C, and the baking time is 5 minutes.

[0064] The final flame retardant polyester / cotton blended fabric has a limiting oxygen index of 30.2% and a damage length of 9.8 cm (see the picture after the vertical burning test). Figure 1 As shown), the total smoke release is 0.58m 2 , the maximum heat release rate is 275kW / m 2 , the residual carbon content is 10.5%.

[0065] Comparative Example 1

[0066] A method for flame retardant finishing of polyester / cotton blended fabric with wool dissolving solution is basically the same as Example 1, except that the same mass of zinc chloride is used in this comparative example to replace the tin tetrachloride in the original Example 1, and other conditions remain unchanged.

[0067] The flame retardant polyester / cotton blended fabric finally obtained has a limiting oxygen index of 27.7%, a damaged length of 13.6 cm, and a total smoke release of 0.69 m 2 , the maximum heat release rate is 465kW / m 2, the residual carbon content is 3.5%.

[0068] Compared with Example 1, the flame retardant properties, smoke suppression properties, and heat suppression properties of the flame retardant polyester / cotton blended fabric prepared in Comparative Example 1 are all deteriorated. This is because zinc chloride is ionized in an aqueous solution but not hydrolyzed, and cannot form an insoluble precipitate after combining with disodium hydrogen phosphate. Therefore, zinc ions are combined with wool proteins through weak coordination chelation, and the flame retardant efficiency of zinc ions is relatively poor, resulting in a decrease in the flame retardant properties of the final flame retardant polyester / cotton blended fabric.

[0069] Comparative Example 2

[0070] A method for flame retardant finishing of polyester / cotton blended fabric with wool dissolving liquid is basically the same as Example 1, except that the treatment temperature in step (2.1) of this comparative example is 50°C.

[0071] The final flame retardant polyester / cotton blended fabric has a limiting oxygen index of 28.2%, a damaged length of 12.5 cm, and a total smoke release of 0.65 m 2 , the maximum heat release rate is 420kW / m 2 , the residual carbon content is 3.9%.

[0072] Compared with Example 1, the flame retardant properties, smoke suppression properties and heat suppression properties of the flame retardant polyester / cotton blended fabric prepared in Comparative Example 2 are all deteriorated. This is because the surface of the wool fiber is rich in scale layers, which will hinder the diffusion of the flame retardant into the interior of the wool fiber. When the temperature is low, the wool scale layer cannot be opened, resulting in the flame retardant being only adsorbed on the surface of the wool fabric and combined to produce precipitation. Most of the flame retardants cannot be fully combined with wool protein and are difficult to be evenly dispersed on the surface of the polyester / cotton blended fabric.

[0073] Comparative Example 3

[0074] A method for flame retardant finishing of polyester / cotton blended fabric with wool dissolving liquid is basically the same as Example 1, except that the same mass of trimethyl phosphate is used in this comparative example to replace the disodium hydrogen phosphate in the original Example 1, and other conditions remain unchanged.

[0075] The final flame-retardant polyester / cotton blended fabric has a limiting oxygen index of 28.3%, a damaged length of 12.4 cm, and a total smoke release of 0.62 m 2 , the maximum heat release rate is 413kW / m 2 , the residual carbon content is 4.1%.

[0076] Compared with Example 1, the flame retardant properties, smoke suppression properties and heat suppression properties of the flame retardant polyester / cotton blended fabric prepared in Comparative Example 3 are all deteriorated. This is because trimethyl phosphate does not contain a phosphate anion group and cannot combine with tin chloride to form basic tin phosphate, and has poor binding ability with wool fibers. It only combines with wool proteins through weak interactions such as hydrogen bonds and van der Waals forces, resulting in a decrease in the flame retardant properties of the flame retardant polyester / cotton blended fabric.

[0077] Example 2

[0078] A method for flame retardant finishing of polyester / cotton blended fabric using wool dissolving liquid, the specific steps are as follows:

[0079] (1) Prepare the raw materials:

[0080] wool fabric;

[0081] Tin tetrachloride solution: the solvent is water;

[0082] Disodium hydrogen phosphate solution: the solvent is water;

[0083] Sodium silicate solution: the solvent is water;

[0084] Sodium hypophosphite;

[0085] Citric acid;

[0086] Polyester / cotton blended fabric: polyester content is 50wt%, limiting oxygen index is 19.3%, damage length is 30cm, total smoke release is 0.70m 2 , the maximum heat release is 470kW / m 2 , the residual carbon content is 1.2%;

[0087] (2) Preparation of flame retardant finishing liquid:

[0088] (2.1) Immerse wool fabric in tin tetrachloride solution at 87°C for 50 min;

[0089] The concentration of the tin tetrachloride solution is 6 g / L, and the mass ratio of the wool fabric to the tin tetrachloride solution is 1:35;

[0090] (2.2) immersing the wool fabric treated in step (2.1) in a disodium hydrogen phosphate solution at 87° C. for 50 min;

[0091] The concentration of the disodium hydrogen phosphate solution is 35 g / L, and the mass ratio of the wool fabric to the disodium hydrogen phosphate solution is 1:35;

[0092] (2.3) immersing the wool fabric treated in step (2.2) in a sodium silicate solution at 87° C. for 50 min to obtain a wool solution;

[0093] The concentration of the sodium silicate solution is 25 g / L, and the mass ratio of the wool fabric to the sodium silicate solution is 1:35;

[0094] (2.4) uniformly mixing sodium hypophosphite, citric acid and the wool solution obtained in step (2.3) to obtain a flame retardant finishing solution;

[0095] In the flame retardant finishing liquid, the concentration of sodium hypophosphite is 16g / L and the concentration of citric acid is 35g / L;

[0096] (3) Flame retardant finishing of polyester / cotton blended fabrics:

[0097] The flame retardant polyester / cotton blended fabric is obtained by sequentially subjecting the polyester / cotton blended fabric to two-immersion and two-rolling, pre-baking and baking treatments;

[0098] Among them, the total time of the double immersion and double rolling is 10 minutes, the rolling rate of the double immersion and double rolling is 95%, the pre-baking temperature is 63°C, the pre-baking time is 4 minutes, the baking temperature is 143°C, and the baking time is 4 minutes.

[0099] The flame retardant polyester / cotton blended fabric finally obtained has a limiting oxygen index of 30.9%, a damaged length of 9.1 cm, and a total smoke release of 0.51 m 2 , the maximum heat release rate is 262kW / m 2 , the residual carbon content is 11.8%.

[0100] Example 3

[0101] A method for flame retardant finishing of polyester / cotton blended fabric using wool dissolving liquid, the specific steps are as follows:

[0102] (1) Prepare the raw materials:

[0103] wool fabric;

[0104] Tin tetrachloride solution: the solvent is water;

[0105] Disodium hydrogen phosphate solution: the solvent is water;

[0106] Sodium silicate solution: the solvent is water;

[0107] Sodium hypophosphite;

[0108] Citric acid;

[0109] Polyester / cotton blended fabric: polyester content is 65wt%, limiting oxygen index is 19.4%, damage length is 30cm, total smoke release is 0.70m 2 , the maximum heat release is 468kW / m 2 , the residual carbon content is 1.3%;

[0110] (2) Preparation of flame retardant finishing liquid:

[0111] (2.1) Immerse wool fabric in tin tetrachloride solution at 89°C for 40 min;

[0112] The concentration of the tin tetrachloride solution is 8 g / L, and the mass ratio of the wool fabric to the tin tetrachloride solution is 1:35;

[0113] (2.2) immersing the wool fabric treated in step (2.1) in a disodium hydrogen phosphate solution at 89° C. for 40 min;

[0114] The concentration of the disodium hydrogen phosphate solution is 40 g / L, and the mass ratio of the wool fabric to the disodium hydrogen phosphate solution is 1:35;

[0115] (2.3) immersing the wool fabric treated in step (2.2) in a sodium silicate solution at 89° C. for 40 minutes to obtain a wool solution;

[0116] The concentration of the sodium silicate solution is 30 g / L, and the mass ratio of the wool fabric to the sodium silicate solution is 1:35;

[0117] (2.4) uniformly mixing sodium hypophosphite, citric acid and the wool solution obtained in step (2.3) to obtain a flame retardant finishing solution;

[0118] In the flame retardant finishing liquid, the concentration of sodium hypophosphite is 18g / L and the concentration of citric acid is 40g / L;

[0119] (3) Flame retardant finishing of polyester / cotton blended fabrics:

[0120] The flame retardant polyester / cotton blended fabric is obtained by sequentially subjecting the polyester / cotton blended fabric to two-immersion and two-rolling, pre-baking and baking treatments;

[0121] Among them, the total time of the double immersion and double rolling is 10 minutes, the rolling rate of the double immersion and double rolling is 100%, the pre-baking temperature is 67°C, the pre-baking time is 3.5 minutes, the baking temperature is 146°C, and the baking time is 3.5 minutes.

[0122] The final flame-retardant polyester / cotton blended fabric has a limiting oxygen index of 31.4%, a damaged length of 8.6 cm, and a total smoke release of 0.49 m 2 , the maximum heat release rate is 255kW / m 2 , the residual carbon content is 12.3%.

[0123] Example 4

[0124] A method for flame retardant finishing of polyester / cotton blended fabric using wool dissolving liquid, the specific steps are as follows:

[0125] (1) Prepare the raw materials:

[0126] wool fabric;

[0127] Tin tetrachloride solution: the solvent is water;

[0128] Disodium hydrogen phosphate solution: the solvent is water;

[0129] Sodium silicate solution: the solvent is water;

[0130] Sodium hypophosphite;

[0131] Citric acid;

[0132] Polyester / cotton blended fabric: polyester content is 80wt%, limiting oxygen index is 19.5%, damage length is 30cm, total smoke release is 0.69m 2 , the maximum heat release is 465kW / m 2 , the residual carbon content is 1.5%;

[0133] (2) Preparation of flame retardant finishing liquid:

[0134] (2.1) Immerse wool fabric in tin tetrachloride solution at 90°C for 30 min;

[0135] The concentration of the tin tetrachloride solution is 10 g / L, and the mass ratio of the wool fabric to the tin tetrachloride solution is 1:40;

[0136] (2.2) immersing the wool fabric treated in step (2.1) in a disodium hydrogen phosphate solution at 90° C. for 30 min;

[0137] The concentration of the disodium hydrogen phosphate solution is 50 g / L, and the mass ratio of the wool fabric to the disodium hydrogen phosphate solution is 1:40;

[0138] (2.3) immersing the wool fabric treated in step (2.2) in a sodium silicate solution at 90° C. for 30 minutes to obtain a wool solution;

[0139] The concentration of the sodium silicate solution is 40 g / L, and the mass ratio of the wool fabric to the sodium silicate solution is 1:40;

[0140] (2.4) uniformly mixing sodium hypophosphite, citric acid and the wool solution obtained in step (2.3) to obtain a flame retardant finishing solution;

[0141] In the flame retardant finishing liquid, the concentration of sodium hypophosphite is 20g / L and the concentration of citric acid is 50g / L;

[0142] (3) Flame retardant finishing of polyester / cotton blended fabrics:

[0143] The flame retardant polyester / cotton blended fabric is obtained by sequentially subjecting the polyester / cotton blended fabric to two-immersion and two-rolling, pre-baking and baking treatments;

[0144] Among them, the total time of the double dipping and double rolling is 10 minutes, the rolling rate of the double dipping and double rolling is 100%, the pre-baking temperature is 70°C, the pre-baking time is 3 minutes, the baking temperature is 150°C, and the baking time is 3 minutes.

[0145] The final flame retardant polyester / cotton blended fabric has a limiting oxygen index of 31.7%, a damaged length of 8.3 cm, and a total smoke release of 0.48 m 2 , the maximum heat release rate is 251kW / m 2 , the residual carbon content is 12.6%.

Claims

1. A method for flame retardant finishing of polyester / cotton blended fabrics using wool dissolving liquid, characterized in that: The following steps are involved: (1) Immerse the wool fabric in a tin tetrachloride solution at a temperature above 85°C; (2) immersing the wool fabric treated in step (1) in a disodium hydrogen phosphate solution at a temperature above 85° C.; (3) immersing the wool fabric treated in step (2) in a sodium silicate solution at a temperature above 85° C. to obtain a wool solution; (4) Finishing the polyester / cotton blended fabric with a flame retardant finishing liquid to obtain a flame retardant polyester / cotton blended fabric; wherein the flame retardant finishing liquid is composed of sodium hypophosphite, citric acid and the wool solution obtained in step (3).

2. The method for flame retardant finishing of polyester / cotton blended fabrics with wool dissolving liquid according to claim 1, characterized in that: In steps (1) to (3), the treatment temperature range is 85 to 90° C., and the treatment time range is 30 to 60 minutes.

3. The method for flame retardant finishing of polyester / cotton blended fabrics with wool dissolving liquid according to claim 1, characterized in that: In step (1), the concentration of the tin tetrachloride solution is 4-10 g / L, and the mass ratio of the wool fabric to the tin tetrachloride solution is 1:30-40.

4. The method for flame retardant finishing of polyester / cotton blended fabrics with wool dissolving liquid according to claim 1, characterized in that: In step (2), the concentration of the disodium hydrogen phosphate solution is 30-50 g / L, and the mass ratio of the wool fabric to the disodium hydrogen phosphate solution is 1:30-40.

5. The method for flame retardant finishing of polyester / cotton blended fabric with wool dissolving liquid according to claim 1, characterized in that: In step (3), the concentration of the sodium silicate solution is 20-40 g / L, and the mass ratio of the wool fabric to the sodium silicate solution is 1:30-40.

6. The method for flame retardant finishing of polyester / cotton blended fabrics with wool dissolving liquid according to claim 1, characterized in that: In the flame retardant finishing liquid of step (4), the concentration of sodium hypophosphite is 15-20 g / L, the concentration of citric acid is 30-50 g / L, and the content of polyester in the polyester / cotton blended fabric is 20-80 wt%.

7. The method for flame retardant finishing of polyester / cotton blended fabrics with wool dissolving liquid according to claim 6, characterized in that: In step (4), the finishing is sequentially performed by double dipping and double rolling, prebaking and baking, wherein the total duration of the double dipping and double rolling does not exceed 10 minutes, the rolling rate of the double dipping and double rolling is 90-100%, the prebaking temperature is 60-70° C., the prebaking time is 3-5 minutes, the baking temperature is 140-150° C., and the baking time is 3-5 minutes.

8. The method for flame retardant finishing of polyester / cotton blended fabrics by using wool dissolving liquid according to any one of claims 1 to 7, characterized in that: Flame retardant polyester / cotton blended fabrics: Limiting oxygen index ≥ 30.2%, damaged length ≤ 9.8 cm, total smoke release ≤ 0.58 m 2 , maximum heat release rate ≤275kW / m 2 , residual carbon content ≥10.5%.

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