METHOD FOR DYEING A HOOK-AND-LOOP FASTENER STRAP

Abstract

A method for dyeing a hook-and-loop fastener strap is disclosed. The hook-and-loop fastener strap continuously passes through a basic or neutral dyeing solution in a dyeing device. The dyeing solution attaches itself to the hook-and-loop fastener strap. The dyeing solution has a dye that binds to the hook-and-loop fastener strap only when the dyeing solution is in an acidic state. After passing through the dyeing device, the hook-and-loop fastener strap with the deposited dyeing solution is passed through a damper, causing the dyeing solution to become acidic. The dye adheres to the hook-and-loop fastener strap to dye the hook-and-loop fastener strap. A dyeing system for implementing the method is also disclosed.

Claims

1. A method for dyeing a hook-and-loop fastener strap having hooks, mushrooms and/or loops, wherein said method having the following sequentially performed steps: a) continuously passing the hook-and-loop fastener strap through a dyeing device to apply a dyeing solution with a pH value of at least 7 to the hook-and-loop fastener strap, wherein the dyeing solution has a dye, wherein the dye is formed as an acid dye which binds to the hook-and-loop fastener strap at a pH value of less than 7; and b) continuously passing the hook-and-loop fastener strap with the applied dyeing solution through a damper, wherein the pH value in the damper is lowered to below 7 to increase adhesion of the dye to the hook-and-loop fastener strap.

2. The method according to claim 1, wherein the dyeing solution has an acid donor designed to release acid at a critical value of a control parameter of the damper to lower the pH of the dyeing solution in the damper.

3. The method according to claim 2, wherein the control parameter is the temperature of the dyeing solution in the damper, wherein the critical value of the control parameter is in the range from 70 C. to 105 C.

4. The method according to claim 2, wherein the dyeing solution has a first masking fabric having an affinity to the dye in the dyeing device at the initial value of the control parameter which is greater than the affinity of a hook-and-loop fastener material of the hook-and-loop fastener strap to the dye, wherein in the damper at the critical value of the control parameter, the affinity of the first masking fabric to the dye is less than the affinity of the hook-and-loop fastener material of the hook-and-loop fastener strap to the dye.

5. The method according to claim 1, wherein the hook-and-loop fastener strap is washed in a first washing apparatus at a temperature of 40 C. to 70 C. before step a).

6. The method according to claim 5, wherein the hook-and-loop fastener strap is washed, before step a), in a second washing apparatus at a temperature of 70 C. to 100 C. after the hook-and-loop fastener strap has been washed in the first washing device.

7. The method according to claim 6, wherein the hook-and-loop fastener strap is washed, before step a), in a third washing apparatus at a temperature of 20 C. to 40 C. after the hook-and-loop fastener strap has been washed in the second washing apparatus.

8. The method according to claim 1, wherein the control parameter is the temperature of the dyeing solution, wherein the critical value of the control parameter in the damper is in the range from 70 C. to 105 C.

9. The method according to claim 1, wherein the hook-and-loop fastener strap has polyamide formed from polyamide.

10. The method according to claim 1, wherein the hook-and-loop fastener strap is continuously passed between two foulard rollers to wipe off excess dyeing solution after the hook-and-loop fastener strap has been passed through the dyeing device according to step a) and before the hook-and-loop fastener strap is passed through the damper according to step b).

11. The method according to claim 1, wherein the dyeing solution has a caustic solution, being soda, wherein the pH of the dyeing solution in the dyeing device is at least 7.

12. The method according to claim 1, wherein the dyeing solution has a defoamer.

13. The method according to claim 1, wherein the hook-and-loop fastener strap passes through a surge drum when leaving the damper.

14. The method according to claim 1, wherein the hook-and-loop fastener strap passes through a vacuum unit.

15. The method according to claim 1, wherein the thickness of the layer of the dye on the hook-and-loop fastener strap does not exceed a predetermined maximum thickness and/or does not fall below a predetermined minimum thickness after running through the method over a predetermined length of the hook-and-loop fastener strap.

16. A dyeing system for carrying out the method according to claim 1, wherein the dyeing system has: I) the dyeing device with the dyeing solution having a pH value of at least 7, wherein the dyeing solution has the dye, wherein the dye is formed as the acid dye which binds to the hook-and-loop fastener strap at a pH value of less than 7; II) the damper, wherein the damper is configured to lower the pH of the dyeing solution to below 7 to increase adhesion of the dye to the hook-and-loop fastener strap; and III) the hook-and-loop fastener strap, wherein the hook-and-loop fastener strap is passed through the dyeing device and the damper.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0066] FIG. 1 schematically shows a longitudinal section through a first part of a dyeing system; and

[0067] FIG. 2 schematically shows a longitudinal section through a first part of a dyeing system.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0068] FIG. 1 schematically shows a longitudinal section through a first part of a dyeing system 10 for a Velcro strap 12, wherein the Velcro strap 12 undergoes a method for dyeing the Velcro strap 12 in the dyeing system 10. The Velcro strap 12 is continuously fed through the dyeing system 10 during the method.

[0069] In the dyeing system 10, the Velcro strap 12 is moved from a drive wheel 14 to a fabric accumulator 16. Statements about the Velcro strap 12 in connection with the method for dyeing the Velcro strap 12 relate, in particular, to a partial section of the Velcro strap 12, which is located on the drive wheel 14 at the beginning of the method and is unrolled from the drive wheel 14 as part of the method in order to undergo the process steps described below. Rollers 18 of the fabric accumulator 16 can be displaced relative to one another, in particular, in the vertical direction, wherein the fabric accumulator 16 can accommodate a partial strip of Velcro strap 12 of different lengths depending on the position of the rollers 18. The fabric accumulator 16 thus serves as a memory and buffer for the Velcro strap 12. After leaving the fabric accumulator 16, the Velcro strap 12 is passed through a web edge control 20, which is designed to adjust the alignment of the Velcro strap 12 for passing through the subsequent stations of the dyeing system 10.

[0070] From the web edge control 20, the Velcro strap 12 passes through a first washing apparatus 22 of a washing system 24. The first washing apparatus 22 is filled with a cleaning solution (indicated by a curved line), which, in particular, has water, preferably exclusively water. In the first washing apparatus 22, the Velcro strap 12 is washed at a temperature in the range of 40 C. to 70 C. This removes dirt spots on the Velcro strap 12. In particular, avivage agents are washed out of the Velcro strap 12 in the first washing apparatus 22. After passing through the first washing apparatus 22, the Velcro strap 12 is passed through a vacuum extractor 26, which extracts the Velcro strap 12 on both sides for the purpose of additional cleaning.

[0071] The Velcro strap 12 then passes through a second washing apparatus 28 of the washing system 24. The second washing apparatus 28 is filled with a cleaning solution (indicated by a curved line), which, in particular, has water, preferably exclusively water. In the second washing apparatus 28, the Velcro strap 12 is washed at a temperature in the range of 70 C. to 100 C. This relieves tension in the Velcro strap 12 to make the Velcro strap 12 more flexible and supple.

[0072] The Velcro strap 12 then passes through another web edge control 20 to adjust its alignment. Thereafter, the Velcro strap 12 is passed through a third washing apparatus 30 of the washing system 24, wherein the Velcro strap 12 is quenched at a temperature in the range of 20 C. to 40 C. to maintain the Velcro strap 12 in the flexible condition effected in the second washing apparatus 28. The third washing apparatus 30 is filled with a cleaning solution (indicated by a curved line), which, in particular, has water, preferably exclusively water.

[0073] After the washing system 24, the Velcro strap 12 is passed through another vacuum extractor 26. In a subsequent step, the Velcro strap 12 is passed through an infrared dryer 32. The infrared dryer 32 ensures that the Velcro strap 12 dries evenly.

[0074] In the direction of movement of the Velcro strap 12 behind the infrared dryer 32, the Velcro strap 12 travels through a cooling path 34 in order to cool the Velcro strap 12. This prevents undesirably early dyeing of the Velcro strap 12, in particular, at a time when the Velcro strap 12 first comes into contact with a dye 40, which is in particular formed as an acid dye, in a dyeing device 36 (see below). The alignment of the Velcro strap 12 is then adjusted in another web edge control 20.

[0075] After the web edge control 20, the Velcro strap 12 passes through the dyeing device 36, which is designed here as a dyeing trough. The dyeing device 36 contains a dyeing solution 38 which has a pH value of at least 7. The dyeing solution 38 is composed of at least the dye 40 and an acid donor 42, wherein the dye 40 is adapted to bind to the Velcro strap 12 at a pH of less than 7. In particular, the dyeing solution 38 has a plurality of dyes 40, wherein each dye 40 serves to dye the Velcro strap 12 in a respective color.

[0076] The acid donor 42 is designed to release acid at a critical value of a control parameter. The control parameter is, in particular, the temperature of the dyeing solution 12. In the dyeing device 36, the dyeing solution 12 has a starting value of the control parameter that is below the critical value of the control parameter. Therefore, the dyeing solution 12 in the dyeing device 36 does not bind to the Velcro strap 12. This allows the dyeing solution 38 to be evenly distributed on the surface of the Velcro strap 12. In particular, different dyes 40 may be prevented from binding to the Velcro strap 12 at different rates so that the concentration of the dyes 40 on the Velcro strap 12 deviates from a desired concentration of the dyes 40, thereby causing an undesirable overall color of the Velcro strap 12. The critical value of the control parameter here is in particular a temperature value of 100 C. of the dyeing solution 38.

[0077] In addition, the dyeing solution 38 also contains, in particular, a first masking fabric 44 and a second masking fabric 46. At the initial value of the control parameter, the first masking fabric 44 binds to the dye 40 faster than a Velcro material 48 of the Velcro strap 12 binds to the dye 40. At the starting value of the control parameter, the second masking fabric 46 binds to the Velcro material 48 of the Velcro strap 12 faster than the dye 40 binds to the Velcro material 48 of the Velcro strap 12. The first and second masking fabrics 44, 46 prevent initial binding of the dye 40 to the Velcro strap 12 so as to improve uniform distribution of the dyeing solution 38 on the surface of the Velcro strap 12 in the dyeing device 36.

[0078] After the dyeing device 36, the Velcro strap 12 is passed through Foulard rollers 50. A distance is formed between the Foulard rollers 50 such that dye 40 is wiped off the surface of the Velcro strap 12 without damaging the structure of the Velcro strap 12. In this process, excess dye 40 is removed from the Velcro strap 12 and the application of dye 40 to the Velcro strap 12 is further homogenized.

[0079] From the Foulard rollers 50, the Velcro strap 12 passes into a damper 52, in which water vapor is present in the form of saturated steam. In this case, atmospheric oxygen is completely or almost completely removed from the damper 52. In the damper, the value of the control parameter is increased to the critical value. In particular, the Velcro strap 12 is heated to at least 100 C. with the applied dyeing solution 38. The acid donor 42 releases acid in the damper 52 when the critical value is reached by the control parameter, in particular, when the dyeing solution 38 on the Velcro strap 12 is heated to 100 C. The pH value of the coloring solution 38 drops to below 7. The first masking fabric 44 is formed such that the first masking fabric 44 in the damper 52 releases the dye 40 when the control parameter assumes the critical value, in particular, when the dyeing solution 38 in the damper 52 is heated to 100 C. The second masking fabric 46 is formed such that the second masking fabric 46 in the damper 52 is replaced by the dye 40 on the Velcro material 48 when the control parameter assumes the critical value, in particular, when the dyeing solution 38 in the damper 52 is heated to 100 C. The lowering of the pH value of the dyeing solution 38 and the altered binding behavior of the masking fabrics 44, 46 in the damper 52 cause the dye 40 to bind to the Velcro strap 12. The binding of the dye 40 to the Velcro strap 12 takes place with uniform distribution and composition of the dye 40 on the surface of the Velcro strap 12. This ensures that the Velcro strap 12 is evenly colored.

[0080] At an output 54 of the damper 52, through which the Velcro strap 12 is guided out of the damper 52, there is a surge drum 56, which is formed here as a water container filled with water (indicated by a curved line). The Velcro strap 12 is guided through the water in the surge drum 56. The water in the surge drum remains transparent if no dye detaches from the Velcro strap 12 and enters the water. Thus, the transparency of the water in the surge drum 56 is an indicator of whether the dye 40 is bound to the Velcro strap 12 as intended.

[0081] FIG. 2 shows schematically in longitudinal section a second part of the dyeing system 10, which adjoins the first part of the dyeing system 10 shown in FIG. 1 in the conveying direction of the Velcro strap 12.

[0082] In the conveying direction of the Velcro strap 12 behind the surge drum 56 (see FIG. 1), the Velcro strap 12 is guided through a further vacuum extractor 26.

[0083] The Velcro strap 12 then passes into a second washing unit of the other washing system 58 with a first washing unit 60, second washing unit 62 and third washing unit 64, which are designed here in the form of open containers in order to remove unbound dyeing solution 38 from the Velcro strap 12. For this purpose, the washing units 60, 62 and 64 of the other washing system 58 each contain a cleaning agent, which is indicated in FIG. 2 by curved lines within the washing units 60, 62, 64. The cleaning agent comprises, in particular, water, preferably exclusively water. Between the first and second washing units 60, 62, the Velcro strap 12 passes through a further web edge control 20. Between the second and third washing units 62, 64, the Velcro strap 12 is guided by a further web edge control 20 to adjust the orientation of the Velcro strap 12.

[0084] A further vacuum extractor 26 for cleaning the dyed Velcro strap 12 is positioned behind the other washing system.

[0085] After the further vacuum extractor 26, the Velcro strap 12 passes through a cylinder of the ironing system 66 with several, in particular, four, electrically heated cylinders 68 arranged in series, along which the Velcro strap 12 is guided. This smooths the Velcro strap 12 for subsequent coating processes. Behind the ironing system 66 there is a further web edge control 20 for adjusting the alignment of the Velcro strap 12.

[0086] In the running direction of the Velcro strap 12 behind the further web edge control 20, the Velcro strap 12 is guided through a flat roller 70. The Velcro strap 12 can be coated efficiently using the flat roller 70.

[0087] The Velcro strap is then fed into a dryer 72, in which the Velcro strap 12 is dried for further use.

[0088] The Velcro strap 12 is rolled up behind the dryer 72 on other drive wheel 74 for further use.

[0089] Taking all the figures of the drawing together, the invention relates in summary to a method for dyeing a Velcro strap 12, wherein the Velcro strap 12 continuously passes through a basic or neutral dyeing solution 38 in a dyeing device 36. The dyeing solution 38 attaches itself to the Velcro strap 12. The dyeing solution 38 has a dye 40 that binds to the Velcro strap 12 only when the dyeing solution 38 is in an acidic state. After passing through the dyeing device 36, the Velcro strap 12 with the deposited dyeing solution 38 is passed through a damper 52, causing the dyeing solution 38 to become acidic. The dye 40 adheres to the Velcro strap 12 to dye the Velcro strap 12. The invention also concerns a dyeing system 10 for implementing the method.

LIST OF REFERENCE SIGNS

[0090] 10 dyeing system [0091] 12 Velcro strap [0092] 14 drive wheel [0093] 16 fabric accumulator [0094] 18 rollers of the fabric accumulator [0095] 20 web edge control [0096] 22 first washing apparatus [0097] 24 washing system [0098] 26 vacuum extractor [0099] 28 second washing apparatus [0100] 30 third washing apparatus [0101] 32 infrared dryer [0102] 34 cooling path [0103] 36 dyeing device [0104] 38 dyeing solution [0105] 40 dye [0106] 42 acid donor [0107] 44 first masking fabric [0108] 46 second masking fabric [0109] 48 Velcro material [0110] 50 Foulard rollers [0111] 52 damper [0112] 54 output of the damper [0113] 56 surge drum [0114] 58 other washing system [0115] 60 first washing unit of the other washing system [0116] 62 second washing unit of the other washing system [0117] 64 third washing unit of the other washing system [0118] 66 ironing system [0119] 68 cylinder of the ironing system [0120] 70 flat roller [0121] 72 dryer [0122] 74 other drive wheel