A new dyeing method using metallic mordant salts for dyeing woolen textile products with direct dyestuffs

Abstract

The invention relates to a new dyeing method developed for dyeing woolen products such as fabrics, fibers, etc. with direct dyestuffs in the presence of metallic mordants (chemical mordants) and bio-mordants in the textile industry.

Description

[0001] A NEW DYEING METHOD USING METALLIC MORDANT SALTS FOR DYEING WOOLEN TEXTILE PRODUCTS WITH DIRECT DYESTUFFS

[0002] Field of the Invention

[0003] The invention relates to a new dyeing method developed for dyeing woolen products such as fabrics, fibers, etc. with direct dyestuffs in the presence of metallic mordants (chemical mordants) and bio-mordants in the textile industry.

[0004] State of the Art

[0005] Wool has a more complex structure than other types of fibers, and physical properties , for example, the physical structure of the fiber, are very important in dyeing wool fibers. Even in a sample of the same quality, the diameter of the wool fibers is quite different. Since the diffusion of the dyestuff into the fiber occurs through the surface and the unit surface corresponding to the unit weight of the material is greater in thin fibers, generally thin fibers adsorb the dyestuff more than thick fibers.

[0006] In the art, acid and metal-complex dyestuffs are primarily used in dyeing woolen fabrics. During dyeing, the temperature can rise up to 105°C. Metal-complex dyestuffs are actually acid dyestuff molecules that form complexes with a metal atom, such as chromium, during the dye production process. Metal-complex dyestuffs are acid dyes that are produced in a complexed form with a metal atom. However, unlike normal acid dyes, dyestuff molecules are complexed with a metal atom. In 1 :1 metal-complex dyes, one acid dye molecule is complexed with one metal atom, and in 1 :2 (or 2:1) metal-complex dyes, two acid dye molecules are also complexed with one metal atom. Chromium is the most commonly used metal. The reason why these dyestuffs are called "acid dyestuffs" is that the dyeing applications are necessarily carried out under acidic conditions. In the art, there are studies conducted with acid dyestuffs used in dyeing woolen fabrics. However, in these studies, there is no process to improve the colors obtained after the application of acid dyestuffs to wool fabrics.

[0007] Although it is possible to use chromium-mordant (or mordant only) dyes in the dyeing of woolen products as alternatives, chromium metal is added to the dyeing bath in order to complex the acid dye in the fiber in the dyeing steps. Since the residual chromium metal remaining in the solution poured into the drain after dyeing causes great damage to the nature, chromium-mordant dyeing is not used today.

[0008] Although dyeing of woolen products can also be done with wool-type reactive dyes, wooltype reactive dyes are not preferred in dyeing woolen products since the desired color results cannot be obtained in applications.

[0009] The acid dyes used in the dyeing of woolen products are fundamentally in three different sizes, as the molecular size of the acid dyes used for this dyeing process increases, although there is initially an improvement in washing fastness, achieving even dyeing and the desired color becomes more challenging. In the use of small molecule acid dyes, although the even dyeing and the desired color hue can be obtained more easily, the washing fastness of these dyeings remains low. In the dyeing of woolen products with acid dyes, achieving level dyeing and obtaining the desired wet fastness cannot be realized at the same time. Therefore, in the state of the art, there is a need for a new dyeing method in which both uniform dyeing and good wet fastness can be obtained.

[0010] Direct dyestuffs are dyestuffs with anionic functional groups similar to acid dyestuffs. Chemically, their molecular structure is usually larger than that of acid dye molecules. Direct dyestuffs have historically been used primarily in the dyeing of cellulosic based fibers such as cotton and viscose rayon. However, as a result of the increasing use of reactive dyestuffs for dyeing these fibers in the mid-1950s, they became less important in the market. The main reason for this is that direct dyestuffs cannot form strong bonds in the fiber structure and can only be hold in the fiber with weak forces such as hydrogen bonds and van der Waals. As a result, the wet fastness of direct dyestuff applications is low. The advantage of these dyes is that when their molecular size in the fiber is increased, it becomes very difficult for them to get out of the fiber in wet processes, and as a result, they can give dyes with higher wet fastness. Direct dyestuffs are particularly sensitive to strong acidic pH conditions in solution. Wool fibers, on the other hand, can be dyed at acidic pH values, especially with dyes with anionic functional groups.

[0011] Under industrial practice conditions, direct dyes are not used in the dyeing of fabrics made of wool fibers, primarily because the wet fastness results are poor and direct dyes are sensitive to certain acidic conditions.

[0012] In the research conducted in the literature, the document numbered WO9845527A1 can be shown as an example of the state of the art. Said document relates to a method of producing textiles having undulating, irregular, shaded and watery appearance . The said method comprises the steps of subjecting the textile material to pretreatment with a resist agent; and coloring the textile material. However, there is no mention of the application of chlorination pretreatment, pre-meta or post mordanting application for dyeing of wool fabrics. In the document, no solution could be found to make direct dyestuff applications in wool fabrics efficient and to increase wet fastness.

[0013] Our patent application numbered 2023 / 006582 in the literature relates to a new dyeing method comprising two-step mordanting for dyeing lyocell textile products with direct dyestuffs. The said application discloses a method for dyeing lyocell fabrics comprising the use of metallic mordants (chemical mordants) or bio-mordants before dyeing and after dyeing. However, the application does not contain any information on the dyeing of woolen fabrics and it is not mentioned that chlorination is applied to woolen fabrics and then applying direct dyestuffs and that dyeing is made efficient by pre- or meta- or post mordanting applications.

[0014] As a result due to said disadvantages and the insufficiency of the current solutions regarding the subject matter, a development is required to be made in the relevant technical field.

[0015] Brief Description of the Invention

[0016] The invention relates to a dyeing method developed for dyeing woolen textile products with direct dyestuffs in the presence of metallic mordants (chemical mordants) and biomordants, which meets said requirements, eliminates all the disadvantages and brings some additional advantages.

[0017] The main objective of the invention is to provide a method developed for the efficient dyeing of woolen textile products with direct dyestuffs using metallic mordants (chemical mordants) and bio-mordants. With the use of metallic (chemical) mordant or bio-mordant, all of the dyestuff in the dyeing solution is absorbed from the solution by the fibers and in addition to the ionic bonds, hydrogen bonds and van der Waals bonds that may occur in the fiber in the acidic medium, all direct dye molecules in the fiber, whether they are bonded or not, are interlocked with metallic (chemical) mordant or bio-mordant molecules to form water insoluble complexes. This complex is formed as a result of the combination of the negative charge of the dye molecule with the positive charge from the metallic mordant molecule. Thus, dye molecules lose their solubility in water by forming larger aggregates. As a result, it is mainly aimed to absorb all dye molecules from the dyeing solution into the fiber and to increase the wet fastness results.

[0018] The objective of the invention is to remove the scales layer forming the outer layer of the wool fibers with the chlorination pretreatment (any decortication process) before dyeing and to make the wool fibers more suitable for the dyeing process by exposing the cortex cell structure.

[0019] An objective of the invention to provide a method in which metallic mordants (chemical mordants) and bio-mordants can be applied in the form of pre-mordanting or meta mordanting or post-mordanting in the dyeing of woolen fabrics with direct dyestuffs. To provide a method that does not require the use of large amounts of salt which are required for dyeing woolen products with anionic dyes.

[0020] Another objective of the invention is to provide a dyeing method for woolen products that prevents unsuccessful dyeings with direct dyestuffs in current methods, which reduces excessive dyestuff usage, and ensures the exact attainment of the target color.

[0021] Another objective of the invention is to provide a method developed to prevent the color of woolen products dyed with direct dyestuffs from changing in the face of external factors such as ironing, light, etc. and depending on use (sweat, etc.) after dyeing.

[0022] Another objective of the invention is to provide a method in which direct dyes classified as “A class dyes", “B class dyes" and “C class dyes" according to their molecular size can be applied with three different mordanting processes.

[0023] Another objective of the invention is to provide a dyeing method applied under weakly acidic conditions in the range of pH 5-7, in the range of 98-105°C dyeing temperature.

[0024] In order to fulfil the above-mentioned objectives, the invention is a method developed for dyeing woolen textile products with direct dyestuffs, comprises the following process steps; i. Chlorination pretreatment to modify the fibers of the woolen textile product and then washing ii. Preparation of the dyeing solution in the range of pH 5-7, iii. Immersing the woolen textile product in the dyeing solution, iv. Adding direct dyestuffs to the dyeing solution, v. Performing the dyeing process by keeping the product in the dyeing solution for 30- 120 minutes at a temperature range of 98-10513, vi. applying washing and drying processes to the product after the dyeing process and applying the mordanting process by adding bio-mordant and / or metallic mordant salts before process step iv) or during process step iv) with direct dyestuffs or after the process step iv).

[0025] The structural and characteristic features and all the advantages of the invention will be understood more clearly by means of the figures and the detailed description with reference to these figures provided below and therefore, the evaluation should be made by taking these figures and the detailed description into consideration.

[0026] Figures for a Better Understanding of the Invention

[0027] Figure 1: The schematic view of the pre-mordanting process

[0028] Figure 2: The schematic view of the meta-mordanting process

[0029] Figure 3: The schematic view of the post mordanting process.

[0030] Descriptions of References

[0031] 1. Direct dyestuffs

[0032] 2. Metallic Mordant or bio-mordant salt

[0033] Detailed Description of the Invention

[0034] In this detailed description, the method of the invention is described solely for the purpose of a better understanding of the subject matter and without any limiting effect.

[0035] The invention relates to a dyeing method in which bio-mordant and / or metallic mordant salts are used in the dyeing of woolen textile products with direct dyestuffs in order to prevent discoloration due to use and external factors after dyeing and to increase the fastness value. Dyeing method fo the invention comprises; i. chlorination pretreatment to modify the fibers of the woolen textile product and then washing, ii. preparation of the dyeing solution in the range of pH 5-7, iii. Immersing the woolen textile product in the dyeing solution, iv. Adding direct dyestuffs to the dyeing solution, v. Performing the dyeing process by keeping the product in the dyeing solution for 30- 120 minutes at a temperature range of 98-10513 vi. Applying washing and drying processes to the product after the dyeing process and applying the mordanting process by adding bio-mordant and / or metallic mordant salts before process step iv) or during process step iv) with direct dyestuffs or after the process step iv).

[0036] In process step i) of the method of the invention, the surface fibers are modified by applying one of the chlorination processes (any decortication process) to the woolen fabric to be dyed. The chlorination process (any decortication process) applied to the woolen textile product can be any of the chlorination processes applied industrially. The desired result here is the complete removal of the scale layer covering the wool fibers. Depending on operational and production characteristics, chlorination can be carried out in the form of fiber, tops, or fabric.

[0037] The fibers forming the woolen fabric to be dyed by the method of the invention are previously subjected to chlorination. Chlorination can be done in the form of fiber, tops or fabric. The chlorination process varies depending on whether the fiber is in the form of fiber, tops or woven fabric. In preferred embodiments of the invention, chlorination is performed at room temperature around pH2 in the presence of active chlorine gas and sodium hypochlorite. Process conditions may vary depending on the physical condition of the fiber material and the selected chlorination chemicals.

[0038] In step (ii) of the method of the invention, the dyeing solution is prepared in the pH range of 5-7 using weak acids. Acetic or formic acid can preferably be used as a weak acid. The dyeing solution is prepared in the temperature range of 40-6013.

[0039] In step (iv) of the method of the invention, direct dyestuffs in the range of 0.5- 8% by weight are added to the dyeing solution. Direct dyes classified as “A class dyes", “B class dyes" and “C class dyes" according to their molecular size from the smallest to the biggest. In the method of the invention, direct dyestuffs selected from A Class, B Class, C Class direct dyestuffs are used. In the step (vi) of the method of the invention, after dyeing, washing process is applied for 40 minutes in a solution containing anionic and nonionic surfactant, preferably at 5013. After that, it is preferably rinsed for 20 minutes in the presence of tap water and after rinsing, drying is conducted preferably at 9013.

[0040] The dyeing solution comprises the chlorinated woolen fabric to be dyed, 0.5-8% direct dyestuff, 0.1-5% metallic (chemical) or bio-mordant, enough acetic or formic acid to set the pH to 5-7. The dyeing process is conducted according to a mordanting method where direct dyestuff and mordant chemical additions are made to the dyeing solution.

[0041] In an embodiment of the method of the invention, pre-mordanting process is applied to the woolen textile product at a temperature of 40-60° C for 20-60 minutes by adding biomordant and / or metallic mordant salts to the dyeing solution 20-60 minutes before the process step iv). Here, the pre-mordanting time is 20-60 minutes, and then the dyeing solution temperature is increased to 98-10513. Afte r the proces step iv) in process step v, the dyeing time is 30-120 minutes at 98-10513.

[0042] In another embodiment of the method of the invention, by adding bio-mordant and / or metallic mordant salts together with direct dyestuffs to the dyeing solution at a temperature of 40-60° C and increasing the temperature to the r ange of 98-105 °C, meta- mordanting process is applied to woolen textile products at a temperature of 98-105 ° C for 30-120 minutes.

[0043] In another embodiment of the method of the invention, bio-mordant and / or metallic mordant salts were added to the dyeing solution 30-90 minutes after the addition of direct dyestuffs from the process step iv), and the post mordanting process is applied to the woolen textile products in the dyeing solution comprising dyestuff and mordant at a temperature of 98- 10513 for 30-120 minutes. Here, the temperature of the dyeing solution comprising direct dyestuff at a temperature of 40-6013 is increased t o 98-10513 after 30-90 minutes and biomordant and / or metallic mordant salts are added, and then, in the process step v), the woolen textile products in the dyeing solution comprising the dyestuff and mordant are subjected to the post mordanting process at a temperature of 98-10513 for 30-120 minutes.

[0044] Figure 1 shows a schematic representation of the pre-mordanting process. Before the dyeing process of the invention, a chlorination process (any decortication process) must have been carried out on the woolen fabric to be dyed. Dyeing is carried out on the woolen fabrics that have already been chlorinated. In a preferred embodiment of the method of the invention, the woolen textile product is first subjected to chlorination pretreatment to have its fibers modified and then washed. Then a dyeing solution is prepared at temperatures of 40-6013 in the pH range of 5-7 which is adjusted by weak acids and the woolen textile product is immersed in this dyeing solution. Then, bio-mordant and / or metallic mordant salts in the range of 0.1-5% by weight are added to the dyeing solution and pre-mordanting process is applied to the woolen textile product at a temperature of 40-6013 for 20-60 minutes. After pre-mordanting, direct dyestuffs are added to the dyeing solution, preferably in the range of 0.5% to 8% by weight, and then the dyeing solution temperature is raised to 98-10513. The product is dyed by being kept in the dyeing solution at a temperature of 98- 10513 for 30-120 minutes. Washing and drying proce sses are applied to the product after the dyeing process.

[0045] Figure 2 shows a schematic representation of the meta-mordanting process. In a preferred embodiment of the method of the invention, the woolen textile product is first subjected to chlorination pretreatment (any decortication process) to have its fibers modified and then washed. A dyeing solution is then prepared at temperatures of 40-6013 in the pH range of 5-7 and the woolen textile product is immersed in this dyeing solution. Then, direct dyestuffs preferably in the range of 0.5- 8% and bio-mordant and / or metallic mordant salts in the range of 0.1 - 5% by weight are added to the dyeing solution, and then the dyeing solution temperature is increased to 98-10513, and dyeing an d meta-mordanting is applied to the wool textile product at this temperature and for 30-120 minutes. Washing and drying processes are applied to the product after the dyeing process.

[0046] Figure 3 shows a schematic representation of the post mordanting process. In a preferred embodiment of the method of the invention, the woolen textile product is first subjected to chlorination pretreatment (any decortication process) to have its fibers modified and then washed. A dyeing solution is then prepared in the pH range of 5-7 and the woolen textile product is immersed in this dyeing solution. Then, direct dyestuffs in the range of 0.5-8% by weight are added to the dyeing solution and dyeing process is applied to the woolen textile product at a temperature of 40-6013 for 20- 60 minutes. Then, the dyeing solution is heated to a temperature range of 98-10513. Afterwa rds , bio-mordant and / or metallic mordant salts in the range of 0.1 - 5% by weight are added to the dyeing solution and post mordanting process is applied the woolen textile product for 30-120 minutes at a temperature of 98-10513. After the dyeing process, washing and drying processes are applied to the product. Here, the washing process is applied for 40 minutes in a solution containing anionic and nonionic surfactant preferably at 50X3 after dyeing . After that, it is preferably rinsed for 20 minutes in the presence of tap water and after rinsing, drying is conducted preferably at 90X3.

[0047] In the method of the invention, the metallic mordant salts used in the pre, meta and post mordanting processes are selected from Potassium Aluminum Sulphate Dodecahydrate [KAI(SO4)2 ■ 12H2O], Iron II Sulfate Heptahydrate (FeSO4-7H2O), Copper sulfate pentahydrate (CuSO45H2O), and Zinc Sulfate Pentahydrate (ZnSO45H2O) and Tannic acid (C76H52O46) is used as bio-mordant.

[0048] With the method of the invention, woolen textile products dyed with direct dyestuffs are provide in which the target color is fully obtained, color change due to use and external factors after dyeing is prevented, the service life is extended and the wet fastness is improved. With this method of ours, products with a longer service life, reduced cost, and maximum benefit are obtained.

[0049] In our method of the invention, dyeing is carried out in the range of pH 5-7. The pH value range used in dyeing is obtained with the use of weak acids. In this specified pH range, the internal structure of the wool fiber becomes positively charged as a result of acid ion (H+) absorption. Under these conditions, the negatively charged direct dyestuff molecules in the dyeing solution can make ionic (electrostatic) bonds with the fiber internal structure. However, it is possible for each dye molecule entering the fiber to make weak hydrogen and van der Waals bonds with its environment without making strong ionic bonds in the fiber. In this way, dyestuff molecules in the fiber, especially those close to the fiber surface layer, dissolve easily in the washes or with water contact during subsequent use and easily desorp from the fiber and stain their environment. The solution offered by the method of the invention against these problems is the use of bio-mordant and / or metallic (chemical) mordant in the dyeing of woolen products with direct dyestuffs. With the use of these biomordant and / or metallic (chemical) mordants, all the dyestuff in the dyeing solution is absorbed from the solution by the fibers and in addition to the ionic bonds, hydrogen bonds and van der Waals bonds that may occur in the fiber in the acidic environment, all the direct dye molecules in the fiber interlocks with the mordant molecules to form water insoluble complexes. This complex is formed as a result of the combination of the negative charge of the dye molecule with the positive charge from the metallic mordant molecule. Thus, dye molecules lose their solubility in water. As a result, firstly, all dye molecules from the dyeing solution are absorbed into the fiber and the wet fastness results increase.

[0050] Direct dyes classified as “A class dyes", “B class dyes" and “C class dyes" according to their molecular size from the smallest to the biggest. All these molecular size classes can be used in our method of the invention. In our method, which is the subject of our invention, direct dyestuffs are used in the dyeing of woolen textile products in the amount of 0.5 - 8% of the mass (weight) of the textile material (yarn, fabric, etc.). For example, 3% dyeing means that 100 kg of fabric (textile material) will be dyed in the dyeing solution to which 3 kg of dyestuff is added (3% owf (on weight of fabric / fiber) has the same meaning).

[0051] Large amounts of salt are required in the dyeing of woolen products with anionic dyes. With the method of the invention, coloring is provided with direct dyestuffs by using metallic mordant or bio-mordant in the range of 0.1-5% of the mass of textile material without the use of standard salt. In addition to this coloring result, the wet fastness of the dyeing is provided and the reducing of color loss is ensured. For example, a 3% mordant addition means that 100 kg of fabric (textile material) will be immersed in a dyeing solution comprising 3 kg of mordant salts.

[0052] The acid-base properties of the solution are provided by the concentrations of hydrogen (H+) and hydroxyl (OH-) ions in the solution. The term 'pH‘ is universally used for both acidic and basic properties in the range expressed as the pH scale. pH values between 1-7 refer to the acidic properties of the solution, and pH values between 7-14 refer to the basic properties of the solution.

[0053] Although the invention can also be applied to dyestuffs with anionic functional group (reactive, direct, acid, metal-complex), the fixation reactions of these dyes in the relevant fibers (wool fibers and other fibers) are different from each other. Mordant application alters these fixation reactions or additionally creates new fixation mechanisms. Apart from the metallic (chemical) mordants given in the invention, other metallic (chemical) mordant or bio-mordants can also be used.

[0054] The products obtained by the method of our invention were analyzed for washing fastness. As a standard, chlorinated woolen fabric is dyed directly using direct dyestuffs. The sample fabric dyed by the method of the invention was dyed with direct dyestuffs in the presence of Iron II Sulfate Heptahydrate mordant salt. After the dyeing was completed, the washing fastness test was applied according to ISO 105 C06 B1 M washing fastness standard without any washing, then the fabrics were dried. L *, a *, b *, C*, h and K / S values were determined before and after the washing fastness test of the fabrics by color measurement in the reflectance spectrophotometer.

[0055] Tablo 1 Experimental results

[0056] The color coordinate values obtained as a result of the dyeing performed using the method of the invention, which involves pre-mordanting method in the presence of Iron II Sulfate Heptahydrate, one of the chemical (metallic) salts, are presented in Table 1. According to these results, a darker dyeing color depth was obtained for the same dyeing concentration in the presence of Iron II Sulfate chemical (metallic) mordant. These color coordinate values show that better coloring results are obtained in direct dyestuff applications in woolen fabrics with the use of mordant.

Claims

CLAIMS1. / method developed for dyeing woolen textile products with direct dyestuffs, characterized by comprising; the following process steps: i. chlorination pretreatment to modify the fibers of the woolen textile product and then washing , ii. preparation of the dyeing solution in the range of pH 5-7, iii. Immersing the woolen textile product in the dyeing solution, iv. Adding direct dyestuffs to the dyeing solution, v. Performing the dyeing process by keeping the product in the dyeing solution for 30-120 minutes at a temperature range of 98-10513 vi. Application of washing and drying processes to the product after the dyeing process and applying the mordanting process by adding bio-mordant and / or metallic mordant salts before process step iv) or during process step iv) with direct dyestuffs or after the process step iv).

2. The dyeing method according to claim 1 , characterized in that; in step (ii), the dyeing solution is prepared at a pH range of 5-7 using weak acids at 40- 6013 temperature.

3. The dyeing method according to claim 1 , characterized in that; in step (iv), direct dyestuffs are added in the range of 0.5- 8% by weight .

4. The dyeing method according to claim 1 , characterized in that; in step (iv), the said direct dyestuffs are selected from A Class, B Class, C Class.

5. The dyeing method according to claim 1 , characterized in that; pre-mordanting process is applied to the woolen textile product at a temperature of 40-60° C for 20-60 minutes by adding bio-mordant and / or metallic mordant salts to the dyeing solution 20-60 minutes before the process step iv).

6. The dyeing method according to claim 1 , characterized in that; bio-mordant and / or metallic mordant salts are added to the dyeing solution at a temperature of 40-60° C together with direct dyestuffs and the temperature is increased to the range of 98-10513 and meta-mordanting process is applied to woolen textile products at a temperature of 98-10513 for 30-120 minutes.

7. The dyeing method according to claim 1 , characterized in that; bio-mordant and / or metallic mordant salts are added to the dyeing solution 30-90 minutes after the addition of direct dyestuffs from the process step iv), and the post mordanting process is applied to the woolen textile products in the dyeing solution comprising dyestuff and mordant at a temperature of 98-105 3 for 30-120 minutes.

8. The dyeing method according to any claims 1 or 5-7, characterized in that; mordanting process is carried out with a metallic mordant salt selected from the group comprising Potassium Aluminum Sulfate Dodecahydrate, Iron II Sulfate Heptahydrate, Copper sulfate pentahydrate, Magnesium sulfate, Zinc Sulfate Pentahydrate.

9. The dyeing method according to any claims 1 or 5-7, characterized in that; mordanting process is carried out with Tannic acid selected as the bio-mordant.

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