Novel process for improving printing effect of nylon rotary screen

Abstract

The invention discloses a novel process for improving the printing effect of a nylon rotary screen, and belongs to the technical field of textile manufacturing. By optimizing the preparation method of the dye in rotary screen printing, the dissolving property of the dye can be remarkably improved, so that the diffusion rate and the level-dyeing property of the dye are improved, the diffusion and level-dyeing properties of the dye in the nylon fabric are improved, and in combination with control over the mesh size of a printing nickel screen, the size of a magnetic bar and the size of magnetic force in the printing process, the printing quality is improved. The dye can be uniformly dispersed in the nylon fabric, and the problems of chromatic aberration and pocking marks are avoided. Moreover, the process provided by the invention can effectively reduce the residual quantity and improve the adsorbability of after-finishing while effectively improving the effect of the cloth cover, so that the effect is better when functional finishing such as mosquito prevention and the like is carried out.

Description

Technical Field

[0001] The invention belongs to the technical field of textile manufacturing, and in particular relates to a new process for improving the printing effect of nylon rotary screen. Background Art

[0002] Nylon fabrics are widely used in military and outdoor sports protective clothing and backpacks due to their excellent strength and wear resistance. However, the output of nylon printed products is not high, mainly because the fabric is easy to pilling, and its washability and wearability are worse than those of polyester. At the same time, during the printing process, the dye has a strong affinity with the fiber, the diffusion rate is low, and the levelness is poor. In the actual production process, the fabric surface is prone to pitting, resulting in defects in the printed products and color differences on the surface of the fabric. When matching colors, if the dye is not selected properly, the color of the product is difficult to control, the dyeing hiding power is poor, especially for high-count and high-density fabrics, the color paste is more difficult to penetrate, and the printed products have more problems.

[0003] For rotary screen nylon printing, the problem of fabric surface dyeing has always been a serious problem that plagues the production of nylon printing. Nylon fibers have high crystallinity, compact structure, strong hydrophobicity, and few polar groups that can combine with dye molecules in the molecules. The internal lacks the pores necessary for dye diffusion, resulting in dye molecules can only diffuse or penetrate into the unobstructed area of ​​the fiber molecules, but cannot enter the crystal area, resulting in low dye uptake. Domestic considerations for improving the rotary screen printing effect of nylon fabrics are mainly from the following aspects: first, the use of acid dyes with good solubility; second, the use of printing pastes with physical and chemical stability; third, the use of surfactants that have a dispersing and solubilizing effect on dyes, but these methods also have many limitations, such as high cost, incomplete chromatography, and poor dyeing effect. Summary of the invention

[0004] In view of the above-mentioned prior art, the present invention provides a new process for improving the nylon rotary screen printing effect, so as to solve the technical problem that the nylon rotary screen printing effect is poor due to the poor solubility of the dye when dyeing the existing fabrics.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is to provide a new process for improving the nylon rotary screen printing effect, comprising the following steps: S1: Turning, scouring and shaping the grey cloth in sequence to obtain a shaped fabric; S2: padding the shaped fabric with the dyeing solution, and then pre-drying and drying to obtain the dyed fabric; the speed during the padding process is 40-50 m / min, and the liquid rate after padding with the dyeing solution is 50-70%; the dyeing solution includes dye, anti-migration agent and deionized water; the pre-drying temperature is 100-120°C, and the drying temperature is 120-140°C; S3: Control the mesh size of the printing nickel screen of the printing machine to be 195 meshes, the size of the magnetic rod to be 12, the magnetic force of the magnetic table to be 50N, and dip the dyed bottom fabric into the printing paste at a speed of 45-55m / min to obtain the printed fabric; the printing paste is obtained by the following steps: S31: mixing water with a printing paste, then adding a dye to the resulting mixture, and then adding a cosolvent and urea, and mixing well to obtain a base material; S32: adding a thickener to the base material to make the viscosity of the system 60 Pa·s, and obtaining; the mass percentages of the printing paste, the cosolvent and the urea in the printing paste are 25-35%, 4-8% and 8-12% respectively; S4: drying the printed fabric, baking it to develop color, and then steaming it to obtain the color developing fabric; S5: Soaping the dyed fabric and then fixing the color to obtain the soaped fabric; S6: performing post-finishing on the soap-washed fabric to obtain.

[0006] Based on the above technical solution, the present invention can also be improved as follows.

[0007] Furthermore, the scouring process is to first dip and roll the immersion liquid five times, and then steam; the liquid rate after dipping and rolling the immersion liquid is 70~90%, and the immersion liquid includes the following components in concentrations: scouring agent JG-130 3~5g / L, degreasing agent AWR 5~7g / L, caustic soda 9~12g / L, hydrogen peroxide 4~6g / L, textile auxiliary agent 20g / L; the steaming speed is 35~45m / min, the temperature is 90~110℃, and the time is 50~70min.

[0008] Furthermore, the shaping speed is 85-95 m / min, the shaping temperature is 180-200°C, and the overfeed speed difference is 11 m / min.

[0009] Furthermore, the concentration of the dye in the dyeing solution is 0.5-2 g / L, the concentration of the anti-migration agent is 8-12 g / L; and the anti-migration agent is sodium alginate.

[0010] Further, the dye is at least one of acid red BL, acid yellow GL, acid blue S-BG, acid green AGS, acid green A, Tassini yellow, neutral red S-2B, neutral blue SR, neutral black LD and Tassini yellow FS-G.

[0011] Furthermore, in S2, the pre-baking time is 30 to 60 seconds, and the drying time is 60 to 120 seconds.

[0012] Furthermore, the printing paste is a modified guar gum solution with a concentration of 9wt%; and the cosolvent is fatty alcohol polyoxyethylene ether.

[0013] Furthermore, in S4, the drying temperature is 110-120°C, and the drying speed is 40 m / min; the baking and coloring temperature is 160°C, and the baking and coloring speed is 50 m / min; the steaming temperature is 110-120°C, and the steaming speed is 15-30 m / min.

[0014] Further, the soaping process in S5 is as follows: the first two squares of fabric are washed with clean water at room temperature; then the 3-4 squares of fabric are immersed in soaping liquid and steamed, the soaping liquid includes the following components in concentration: soaping agent NS-405 6-8g / L, quick-training agent 6-8g / L, added every 30 minutes, and the steaming temperature is 70-80°C; then the 7-9 squares of fabric are fixed with a fixing agent solution, the fixing agent solution is a fixing agent PA-01 solution with a concentration of 1-2g / L, added every 30 minutes.

[0015] Furthermore, the post-finishing in S6 is to immerse the soaped fabric in a mosquito repellent finishing liquid and then dry it; the liquid carrying rate during the immersion process is 60%, and the drying temperature is 135°C; the mosquito repellent finishing liquid includes a mosquito repellent SPA-01 with a concentration of 120g / L and a polyacrylate with a concentration of 50g / L.

[0016] The beneficial effects of the present invention are: The present invention can significantly improve the solubility of the dye by optimizing the preparation method of the dye in the rotary screen printing, thereby improving the diffusion rate and leveling performance of the dye, and further improving the diffusion and leveling performance of the dye in the nylon fabric. Combined with the control of the mesh size of the printed nickel screen, the size of the magnetic rod and the size of the magnetic force during the printing process, the dye can be evenly dispersed in the nylon fabric without the problem of color difference and pitting. In addition, the process in the present invention can effectively reduce the residual amount and improve the adsorption of the post-finishing while effectively improving the cloth effect, so that the effect is better when performing functional finishing such as mosquito repellent. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the solubility test result of the dye; Figure 2 This is a graph showing the effects of cosolvents and urea on the solubility of dyes. DETAILED DESCRIPTION

[0018] The specific implementation modes of the present invention are described in detail below with reference to the embodiments.

[0019] Example 1: Solubility test of dye Dissolve acid red S-BL, acid yellow M-GL, Iliir blue AR, Isolan gray NHF-S, weak acid green AGS and other dyes in hot water (about 95℃), stir for 10 minutes, and prepare a dye solution with a concentration of 10% (mass concentration); then leave it for one hour and cool to room temperature; after stirring for 30 seconds, drop it on filter paper to make it disperse freely, and observe the dissolution of the dye after drying. The results are as follows Figure 1 As shown in the figure, it can be seen that these dyes have poor solubility when the dosage is 10%.

[0020] Example 2: Effect of cosolvent and urea on dye solubility Acid red S-BL, acid yellow M-GL, Iliir blue AR, Isolun gray NHF-S, weak acid green AGS and other dyes were dissolved in hot water (about 95℃) to prepare a dye solution with a concentration of 10wt%, and then the co-solvent fatty alcohol polyoxyethylene ether AEO-9 and urea were added. The amount of co-solvent fatty alcohol polyoxyethylene ether AEO-9 added was 1~5wt%, and the amount of urea added was 10wt%. Stir for 10 minutes; then leave it for one hour and cool to room temperature; after stirring for 30s, drop it on filter paper to make it disperse freely, and observe the dissolution of the dye after drying. The results are as follows Figure 2 As shown in the figure, it can be seen that the addition of co-solvent fatty alcohol polyoxyethylene ether AEO-9 and urea can significantly promote the dissolution of the dye and improve the solubility of the dye in water.

[0021] Example 3 A new process for improving nylon rotary screen printing includes the following steps: (1) Turning: Select the grey fabric with the specification of N(66) 160D×160D 90×78 1 / 1 plain weave and turn it over; (2) Scouring: The leaching solution was scourged by five immersions and five rollings; then the scour fabric was steamed at 100°C for 60 min to obtain the scour fabric; during the immersion and rolling process, the vehicle speed was 60 m / min and the liquid carrying rate was 80%; the leaching solution included the following components: scouring agent JG-130 4 g / L, degreasing agent AWR 6 g / L, caustic soda 10 g / L, hydrogen peroxide 5 g / L, textile auxiliary agent (leveling agent DC) 20 g / L; (3) Setting: The scoured fabric is set at 190°C, the setting speed is 90 m / min, the width is maintained at 155 cm, the falling width reaches 153 cm, the overfeed speed difference is 11 m / min, and then rolled to make it wrinkle-free, to obtain a set fabric; (4) dyeing: padding the shaped fabric with the dyeing solution at a speed of 45 m / min, then pre-baking at 110°C for 45 seconds, and then baking at 130°C for 90 seconds to obtain the dyed fabric; during the padding process, the liquid carrying rate was 60%; the dyeing solution included the following components: dye 1 g / L, sodium alginate 10 g / L, wherein the dye was prepared by mixing acid green AGS, neutral blue SR and Tassie yellow FS-G in a mass ratio of 3:3:1; (5) Printing: The mesh size of the nickel screen of the printing machine is controlled to be 195 meshes, the size of the magnetic rod is 12, the magnetic force of the magnetic table is 50N, and the dyed base fabric is dipped in the printing paste at a speed of 50m / min to obtain a printed fabric; the printing paste is prepared by the following steps: S1: mixing water with a modified guar gum solution having a concentration of 9 wt%, then adding dye to the mixture, and then adding co-solvent fatty alcohol polyoxyethylene ether AEO-9 and urea, mixing well to obtain a base material, wherein the dye is a mixture of acid green AGS, neutral blue SR and Tassie yellow FS-G in a mass ratio of 3:3:1; S2: Add acidic thickener DM-5261 (purchased from Guangdong Demei Fine Chemical Group Co., Ltd.) to the base material to make the viscosity of the system 60 Pa·s; the mass percentages of dye, modified guar gum solution, cosolvent BC and urea in the printing paste are 10%, 30%, 6-8% and 10% respectively; (6) Baking for color development: drying the printed fabric at 105°C at a speed of 40 m / min; then baking for color development at 160°C at a speed of 50 m / min, and then steaming at 115°C at a speed of 20 m / min to obtain a colored fabric; (7) Reduction color soaping: Wash the first two squares of the color-developing fabric with clean water at room temperature; then dip the 3-4 squares of fabric into soap solution and steam it. The soap solution includes the following components in concentration: soap agent NS-405 7g / L, quick-cleaning agent 7g / L, and the soap solution is added every 30 minutes. The steaming temperature is 75°C; then fix the 7-9 squares of fabric with a color fixing agent solution. The color fixing agent solution used is a color fixing agent PA-01 solution with a concentration of 1g / L. The color fixing agent solution is added every 30 minutes. (8) Anti-mosquito finishing: The soap-washed fabric is dipped into the anti-mosquito finishing liquid and then dried to obtain the finished fabric; the liquid carrying rate during the dipping process is 60% and the drying temperature is 135°C; the anti-mosquito finishing liquid includes a mosquito repellent SPA-01 with a concentration of 120g / L and a polyacrylate with a concentration of 50g / L.

[0022] Example 4 A new process for improving nylon rotary screen printing includes the following steps: (1) Turning over: Select the grey cloth with the specification of N(66) 160D×160D 90×78 1 / 1 and turn it over; (2) Scouring: The leaching solution was scourged by five immersions and five rollings; then the scour fabric was steamed at 100°C for 60 min to obtain the scour fabric; during the immersion and rolling process, the vehicle speed was 60 m / min and the liquid carrying rate was 80%; the leaching solution included the following components: scouring agent JG-130 4 g / L, degreasing agent AWR 6 g / L, caustic soda 10 g / L, hydrogen peroxide 5 g / L, textile auxiliary agent (leveling agent DC) 20 g / L; (3) Setting: The scoured fabric is set at 190°C, the setting speed is 90 m / min, the width is maintained at 155 cm, the falling width reaches 153 cm, the overfeed speed difference is 11 m / min, and then rolled to make it wrinkle-free, to obtain a set fabric; (4) dyeing: padding the shaped fabric with the dyeing solution at a speed of 45 m / min, then pre-baking at a temperature of 110°C for 45 seconds, and then baking at a temperature of 130°C for 90 seconds to obtain the dyed fabric; during the padding process, the liquid carrying rate is 60%; the dyeing solution includes the following components: 1 g / L dye, 10 g / L sodium alginate, wherein the dye is a mixture of neutral blue SR, Tassie yellow FS-G and neutral red S-2B in a mass ratio of 1:1:1; (5) Printing: The mesh size of the nickel screen of the printing machine is controlled to be 195 meshes, the size of the magnetic rod is 12, the magnetic force of the magnetic table is 50N, and the dyed base fabric is dipped in the printing paste at a speed of 50m / min to obtain a printed fabric; the printing paste is prepared by the following steps: S1: mixing water with a modified guar gum solution having a concentration of 9 wt%, then adding dye to the mixture, and then adding co-solvent fatty alcohol polyoxyethylene ether AEO-9 and urea, mixing well to obtain a base material, wherein the dye is a mixture of neutral blue SR, Tassie yellow FS-G and neutral red S-2B in a mass ratio of 1:1:1; S2: Add acidic thickener DM-5261 to the base material to make the viscosity of the system 60mPa·s, and obtain; the mass percentages of dye, modified guar gum solution, co-solvent fatty alcohol polyoxyethylene ether AEO-9 and urea in the printing paste are 10%, 30%, 6-8% and 10% respectively; (6) Baking for color development: drying the printed fabric at 105°C at a speed of 40 m / min; then baking for color development at 160°C at a speed of 50 m / min, and then steaming at 115°C at a speed of 20 m / min to obtain a colored fabric; (7) Reduction color soaping: Wash the first two squares of the color-developing fabric with clean water at room temperature; then dip the 3-4 squares of fabric into soap solution and steam it. The soap solution includes the following components in concentration: soap agent NS-405 7g / L, quick-cleaning agent 7g / L, and the soap solution is added every 30 minutes. The steaming temperature is 75°C; then fix the 7-9 squares of fabric with a color fixing agent solution. The color fixing agent solution used is a color fixing agent PA-01 solution with a concentration of 1g / L. The color fixing agent solution is added every 30 minutes. (8) Anti-mosquito finishing: The soap-washed fabric is dipped into the anti-mosquito finishing liquid and then dried to obtain the finished fabric; the liquid carrying rate during the dipping process is 60% and the drying temperature is 135°C; the anti-mosquito finishing liquid includes a mosquito repellent SPA-01 with a concentration of 120g / L and a polyacrylate with a concentration of 50g / L.

[0023] Example 5 A new process for improving nylon rotary screen printing includes the following steps: (1) Turning over: Select the grey cloth with the specification of N(66) 160D×160D 90×78 1 / 1 and turn it over; (2) Scouring: The leaching solution was scourged by five immersions and five rollings; then the scour fabric was steamed at 100°C for 60 min to obtain the scour fabric; during the immersion and rolling process, the vehicle speed was 60 m / min and the liquid carrying rate was 80%; the leaching solution included the following components: scouring agent JG-130 4 g / L, degreasing agent AWR 6 g / L, caustic soda 10 g / L, hydrogen peroxide 5 g / L, textile auxiliary agent (leveling agent DC) 20 g / L; (3) Setting: The scoured fabric is set at 190°C, the setting speed is 90 m / min, the width is maintained at 155 cm, the falling width reaches 153 cm, the overfeed speed difference is 11 m / min, and then rolled to make it wrinkle-free, to obtain a set fabric; (4) dyeing: padding the shaped fabric with the dyeing solution at a speed of 45 m / min, then pre-baking at a temperature of 110°C for 45 seconds, and then baking at a temperature of 130°C for 90 seconds to obtain the dyed fabric; during the padding process, the liquid carrying rate is 60%; the dyeing solution includes the following components in the following concentrations: dye 1 g / L, sodium alginate 10 g / L, wherein the dye is prepared by mixing acid green AGS, neutral blue SR and Tassie yellow FS-G in a mass ratio of 1:1:2; (5) Printing: The mesh size of the nickel screen of the printing machine is controlled to be 195 meshes, the size of the magnetic rod is 12, the magnetic force of the magnetic table is 50N, and the dyed base fabric is dipped in the printing paste at a speed of 50m / min to obtain a printed fabric; the printing paste is prepared by the following steps: S1: mixing water with a modified guar gum solution having a concentration of 9 wt%, then adding dye to the mixture, and then adding co-solvent fatty alcohol polyoxyethylene ether AEO-9 and urea, mixing well to obtain a base material, wherein the dye is a mixture of acid green AGS, neutral blue SR and Tassie yellow FS-G in a mass ratio of 1:1:2; S2: Add acidic thickener DM-5261 to the base material to make the viscosity of the system 60mPa·s, and obtain; the mass percentages of dye, modified guar gum solution, co-solvent fatty alcohol polyoxyethylene ether AEO-9 and urea in the printing paste are 10%, 30%, 6-8% and 10% respectively; (6) Baking for color development: drying the printed fabric at 105°C at a speed of 40 m / min; then baking for color development at 160°C at a speed of 50 m / min, and then steaming at 115°C at a speed of 20 m / min to obtain a colored fabric; (7) Reduction color soaping: Wash the first two squares of the color-developing fabric with clean water at room temperature; then dip the 3-4 squares of fabric into soap solution and steam it. The soap solution includes the following components in concentration: soap agent NS-405 7g / L, quick-cleaning agent 7g / L, and the soap solution is added every 30 minutes. The steaming temperature is 75°C; then fix the 7-9 squares of fabric with a color fixing agent solution. The color fixing agent solution used is a color fixing agent PA-01 solution with a concentration of 1g / L. The color fixing agent solution is added every 30 minutes. (8) Anti-mosquito finishing: The soap-washed fabric is dipped into the anti-mosquito finishing liquid and then dried to obtain the finished fabric; the liquid carrying rate during the dipping process is 60% and the drying temperature is 135°C; the anti-mosquito finishing liquid includes a mosquito repellent SPA-01 with a concentration of 120g / L and a polyacrylate with a concentration of 50g / L.

[0024] Results Analysis The fabric effects of the fabrics obtained by the above-mentioned embodiments were tested, and the results are listed in Table 1.

[0025] Table 1 Mosquito repellent effect of fabrics

[0026] Note: The fabric effect is evaluated from the following aspects: color uniformity, back penetration effect, presence of defects, etc. It can be seen from Table 1 that the finished cloth obtained by the new process of the present invention has uniform color, almost no back bleeding and defects, and can effectively improve the effect of nylon rotary screen printing.

[0027] Although the specific implementation of the present invention is described in detail in conjunction with the embodiments, it should not be understood as limiting the scope of protection of this patent. Within the scope described in the claims, various modifications and variations made by those skilled in the art without creative work still fall within the scope of protection of this patent.

Claims

1. A new process for improving nylon rotary screen printing, characterized in that: The following steps are involved: S1: Turning, scouring and shaping the grey cloth in sequence to obtain a shaped fabric; S2: padding the shaped fabric with the dyeing solution, and then pre-drying and drying to obtain the dyed fabric; the vehicle speed during the padding process is 40-50 m / min, and the liquid rate after padding with the dyeing solution is 50-70%; the dyeing solution includes a dye, an anti-migration agent and deionized water; the pre-drying temperature is 100-120°C, and the drying temperature is 120-140°C; S3: Control the mesh size of the printing nickel screen of the printing machine to be 195 meshes, the size of the magnetic rod to be 12, the magnetic force of the magnetic table to be 50N, and dip the dyed bottom fabric into the printing paste at a speed of 45-55m / min to obtain the printed fabric; the printing paste is obtained by the following steps: S31: mixing water with a printing paste, then adding a dye to the resulting mixture, and then adding a cosolvent and urea, and mixing well to obtain a base material; S32: adding a thickener to the base material to make the viscosity of the system 60 Pa·s, to obtain; the mass percentages of the printing paste, the cosolvent and the urea in the printing paste are 25-35%, 4-8% and 8-12% respectively; S4: drying the printed fabric, baking it to develop color, and then steaming it to obtain the color developing fabric; S5: Soaping the dyed fabric and then fixing the color to obtain the soaped fabric; S6: performing post-finishing on the soap-washed fabric to obtain.

2. The new process for improving nylon rotary screen printing effect according to claim 1 is characterized in that: The scouring process is to first dip and roll the immersion liquid five times, and then steam; the liquid rate after dipping and rolling the immersion liquid is 70-90%, and the immersion liquid includes the following components in concentrations: 3-5 g / L of scouring agent JG-130, 5-7 g / L of degreasing agent AWR, 9-12 g / L of caustic soda, 4-6 g / L of hydrogen peroxide, and 20 g / L of textile auxiliary agent; the speed of steaming is 35-45 m / min, the temperature is 90-110° C., and the time is 50-70 min.

3. The new process for improving nylon rotary screen printing effect according to claim 1 is characterized in that: The shaping speed is 85-95 m / min, the shaping temperature is 180-200° C., and the overfeeding speed difference is 11 m / min.

4. The new process for improving nylon rotary screen printing effect according to claim 1 is characterized in that: The concentration of the dye in the base dye solution is 0.5-2 g / L, and the concentration of the anti-migration agent is 8-12 g / L; the anti-migration agent is sodium alginate.

5. The new process for improving nylon rotary screen printing according to claim 1 or 4, characterized in that: The dye is at least one of acid red BL, acid yellow GL, acid blue S-BG, acid green AGS, acid green A, Tassini yellow, neutral red S-2B, neutral blue SR, neutral black LD and Tassini yellow FS-G.

6. The new process for improving nylon rotary screen printing effect according to claim 1 is characterized in that: In S2, the pre-baking time is 30~60s, and the drying time is 60~120s.

7. The new process for improving nylon rotary screen printing effect according to claim 1 is characterized in that: The printing paste is a modified guar gum solution with a concentration of 9wt%; and the cosolvent is fatty alcohol polyoxyethylene ether.

8. The new process for improving nylon rotary screen printing effect according to claim 1 is characterized in that: In S4, the drying temperature is 110~120℃, and the drying speed is 40m / min; the baking and coloring temperature is 160℃, and the baking and coloring speed is 50m / min; the steaming temperature is 110~120℃, and the steaming speed is 15~30m / min.

9. The new process for improving nylon rotary screen printing effect according to claim 1 is characterized in that: The soaping process in S5 is as follows: the first two squares of fabric are washed with clean water at room temperature; then the 3-4 squares of fabric are dipped in soaping liquid and steamed, wherein the soaping liquid includes the following components in concentration: soaping agent NS-405 6-8g / L, quick-training agent 6-8g / L, added once every 30 minutes, and the steaming temperature is 70-80°C; then the 7-9 squares of fabric are fixed with a color fixing agent solution, wherein the color fixing agent solution is a color fixing agent PA-01 solution with a concentration of 1-2g / L, added once every 30 minutes.

10. The new process for improving nylon rotary screen printing effect according to claim 1 is characterized in that: The post-finishing in S6 is to immerse the soaped fabric in the anti-mosquito finishing liquid and then dry it; the liquid carrying rate during the immersion process is 60%, and the drying temperature is 135°C; the anti-mosquito finishing liquid includes the mosquito repellent SPA-01 with a concentration of 120g / L and the polyacrylate with a concentration of 50g / L.

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