JP2006132029A - Method for printing polylactic acid fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for printing polylactic acid fibers, by which color reproducibility, light-resistant fastness, washing fastness, and acidic or alkaline sweat fastness of the fibers are improved. <P>SOLUTION: This method for printing the polylactic acid fibers comprises at least a printing process 1 for printing the polylactic acid fibers with a color paste comprising a mixture of an acrylic polymer, an ultraviolet ray absorbent, a natural paste and a disperse dye, a steaming (heat treatment: HT) treatment process 2 for steaming (HT) the printed polylactic acid fibers under a high temperature humidity circumstance comprising a temperature of about 110°C and a humidity of 75% for a treatment time of 15 min, a water-washing process 3 for washing away the color paste to remove the paste, a hand-adjusting process 4 for adjusting the water-washed polylactic acid fibers, and a finishing process 5 for dry-heating the hand-adjusted polylactic acid fibers. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a printing method for polylactic acid fibers.

Petroleum-based synthetic fibers such as polyester fibers and fabrics can be dyed and printed firmly when dyed, and petroleum-based synthetic fibers are suitable for recycling after being dissolved and re-fibered. It was.
However, when melting for recycling, petroleum-based synthetic fibers have a high melting temperature, which requires a large amount of energy to be used. Furthermore, since halogen is used in order to improve color developability and fast dyeability, dioxins are generated during exhaust treatment by incineration, leading to environmental pollution.
In addition, petroleum resources are finite, and heavy use of synthetic fibers has spurred depletion of natural resources.

  In contrast, polylactic acid fibers are made from plants such as corn, which grows by absorbing carbon dioxide and repeating photosynthesis, which saves valuable petroleum resources and suppresses an increase in carbon dioxide. Furthermore, polylactic acid is a natural circulation type material that biodegrades and returns to the soil when buried in the soil. The lactic acid separated and discharged from the polylactic acid has antibacterial properties and is an extremely safe polymer. Polylactic acid fibers made from polylactic acid are classified as aliphatic polyester fibers, and have attracted attention as natural environment-friendly fibers having gloss and biodegradability while having properties as synthetic fibers. In addition, polylactic acid belongs to the slowest class of biodegradable plastics and hardly decomposes under normal storage conditions, so it is suitable for living materials such as clothing and towels.

Here, the fiber physical properties of polylactic acid fiber and polyester and nylon which are petroleum synthetic fibers are shown in Table 1 below.

As indicated by the physical properties of the above fibers, polylactic acid fibers have a relatively low melting temperature, so that the conditions for dyeing and printing (printing) are limited and it is difficult to improve fastness and color development.
In addition, polylactic acid fiber has a crystal structure in which dye molecules can easily enter, but on the other hand, since dye molecules in one end are also easy to come out, the dyeing fastness in a wet state is low, especially in the middle concentration range or higher. There is a tendency that color reproduction in the density region is low. The above-mentioned tendency was confirmed in a development test in which a disperse dye used for polyester printing was used for polylactic acid fibers.
From the above, when polylactic acid fibers dyed with disperse dyes are worn as innerwear or outerwear, there is a risk that other clothing will be contaminated by sweating or rain, or the color may be lost during washing.

Therefore, a dyeing method for improving the dyeing fastness of the polylactic acid fiber is proposed in Patent Document 1 below. The dyeing method described in this document uses disperse dyes, but there is a risk that the halogen used may generate dioxins during combustion and cause environmental pollution.
Patent Document 2 proposes a transfer printing method in which a sublimation dye transfer material printed with a desired color pattern design is adhered to a portion to be dyed on a fabric formed of polylactic acid fibers and natural fibers, and heat transfer is performed. Yes.

JP 2003-49374 A JP 2004-218170 A

  Therefore, the present invention provides a textile printing method for improving the color reproducibility of an environmentally friendly polylactic acid fiber and improving light fastness, wash fastness, and acid / alkali sweat fastness.

  The polylactic acid fiber printing method of the present invention comprises a printing process of printing polylactic acid fiber with a color paste prepared by mixing and mixing at least an acrylic polymer, an ultraviolet ray cutting agent, a natural glue, and a disperse dye, A steaming (HT) treatment process in which the printed polylactic acid fiber is steamed (HT) for 15 minutes in a hot and humid environment at a temperature of about 110 ° C. and a humidity of 75%. The basic structure includes at least a water washing step, a texture adjusting step for adjusting polylactic acid fibers after water washing, and a finishing process for dry heat-treating the polylactic acid fibers subjected to the texture adjustment.

  Further, in the water washing step, after degliding with cold water, reduction washing is performed for about 20 minutes. In the texture adjustment step, the polylactic acid fibers after water washing are immersed in an amino acid aqueous solution to maintain moisture and lubricate the surface. In the finishing process, a dry heat treatment is performed at a temperature of about 110 ° C. to 120 ° C. and a processing time of 30 seconds to 50 seconds.

  The textile printing method of the present invention achieves improvement in light fastness and washing fastness, acid fastness and alkali sweat fastness and color development of polylactic acid fibers by a simple process.

The best mode for carrying out the present invention will be described below in detail with reference to the drawings.
FIG. 1 shows a printing (printing) process on polylactic acid fibers in the present invention.

As a printing fiber in the textile printing process of the present invention, a polylactic acid fiber may be used alone, or another fiber may be mixed with the polylactic acid fiber. Moreover, as a form, it can be used for any form of cotton and yarn, or a form of fabric such as woven fabric, knitted fabric, and non-woven fabric.
Other fibers mixed with polylactic acid fibers include natural fibers such as cotton, silk, hemp and animal hair, regenerated cellulose fibers such as viscose rayon, polynosic and cupra, and solvent-spun cellulose fibers such as lyocell. Can do.

Printing process 1
Polylactic acid fibers are printed with disperse dyes, UV (ultraviolet rays) cutting agents, and a color paste adjusted with a weakly acidic synthetic paste that does not require pH adjustment.
Print using a screen cage and a cage with a color paste prepared and mixed with paste and dye.
The paste was formulated as 1000 g by dissolving 45 g of a mixture of an acrylic polymer and a natural paste (algin) in ionic water. The mixed paste of the acrylic polymer and the natural paste can be effectively removed by washing with water in a later step.
The dye used was a disperse dye (non-halogen). As the dye, it is preferable to use a disperse dye that contributes to improvement in light fastness and washing fastness, particularly a dye suitable for polylactic acid fibers recommended by a dye manufacturer.
In addition, polylactic acid fibers have high transparency and fade due to the transmission of light over time. However, the light fastness can be improved by using an ultraviolet blocking agent.
To adjust the color paste, the disperse dye is directly transferred to 1000 g of the prescribed paste and stirred at a high speed to make the color paste. At this time, the pH value of the paste is about 6, and pH adjustment with acetic acid or the like is not performed.
The printed polylactic acid fiber is dried by the heat and wind of the printing stand.

Steaming (HT) process 2
The dye is fixed by placing it in a predetermined environment.
There are high pressure steaming (HP), high temperature steaming (HT), dry heat (therm sol) and the like as the environment to be fixed, but in the present invention, it is fixed in a high temperature steaming (HT) environment.
Steaming is performed for 15 minutes in an environment of 75% humidity and 110 ° C.
Since the polylactic acid fiber after steaming dislikes high temperature and humidity, the dehumidifying cooling keeps the humidity rise. In this case, no pressure is applied.

Washing process 3
Remove the printed color paste. After steaming, de-glue with cold water within 24 hours. For de-glue, it is immersed in a water bath overflowed with cold water. After sufficient de-glue while overflowing water, reduction cleaning is performed. The temperature of the reduced washing water is 60 ° C., and the time is 20 minutes.
In reducing cleaning, as a cleaning agent to be used,
Hydrosulfite 2g / L
Alkali (Baking soda) 1g / L
Dispersing dye soaping agent 1g / L
Thus, the amount of alkali used in the cleaning liquid is very small.
Then wash away the detergent with cold water.

Texture adjustment process 4
Make adjustments after washing.
The polylactic acid fiber is immersed (parled) in an aqueous amino acid solution. This prevents the disperse dyes dyed on the polylactic acid fibers from being easily separated from the fibers and transferred to the fiber surface. And it provides antistatic performance (moisturizing property) and surface slip (lubricity) effect. Then, it is dried by passing through a cylinder at 100 ° C.

Finishing process 5
After performing a texture adjustment process and the like and drying, a dry heat treatment is performed at a temperature of 110 ° C. to 120 ° C. for 30 seconds to 50 seconds. For example, recover and set wrinkles with a tenter. Temperature management and time management are important for short-time dry heat treatment. When the dry heat treatment temperature exceeds 110 ° C, the fibers tend to become brittle and the texture tends to deteriorate. The upper limit is 120 ° C and the treatment time is shortened. For example, when the processing temperature is 120 ° C., the processing time is 30 seconds, and when the processing temperature is 110 ° C., the processing time is 50 seconds.
The use of an amino acid in place of the silicone softener in this short-time dry heat treatment and texture adjustment step contributes to prevention of disperse of the disperse dyes dyed on the polylactic acid fiber.

In addition, when printing a fabric, the round winding finishing process 6 (process of round-wrapping the printed fabric) is required.
This is a round roll of what was mechanically shaken off.

  In the finishing process, the polylactic acid fiber thus printed has good colorability in the density area of the medium density area or higher under the processing conditions of 110 ° C. and 50 seconds, has no color blur, and has a fixing rate. high. In addition, the fastness to washing when wet and dry was high. Further, under the processing conditions of 120 ° C. and 30 seconds, the color developability from the middle density region was particularly good.

  As described above, the printing method for polylactic acid fibers having a low melting temperature according to the present invention has a steaming (HT) temperature of about 110 ° C. in the steaming (HT) treatment process, and the steaming (HT) process time is usually normal. By making the steaming (HT) time at about 15 minutes longer than the steaming (HT) time at the time of reactive dyeing, it is possible to reliably fix the color. In addition, the color paste is colored while maintaining a pH of 6 and weak acid throughout without adjusting the pH with an adjusting agent such as acetic acid. Along with this, the amount of alkali used when washing weakly acidic color paste can be suppressed to a low level, so that the washing waste liquid can be poured into sewage.

Further, in the finishing process, usually a work for drawing out for about 3 to 8 minutes is necessary, but in the polylactic acid fiber printing method of the present invention, the dry heat treatment time required for the finishing process is 30 seconds to The heat treatment for about 50 seconds is sufficient, and the time required for printing can be shortened. In addition, the simplification of the printing process can reduce utility costs.
When polylactic acid fibers are buried in the soil, biodegradation begins by bacteria and returns to the soil. At that time, lactic acid is produced from polylactic acid and exhibits antibacterial properties. In addition, polylactic acid fiber itself uses less non-halogen disperse dyes that generate less dioxin and does not generate dioxin during incineration, so there is a risk of dioxin generation during incineration of dyed polylactic acid fiber. It is possible to incinerate with low calories.
In this way, the dyed polylactic acid fiber has no fear of environmental pollution during disposal.
In this embodiment, the dye is a disperse dye. However, when a reactive dye is used, the original paste used here can be shared for overprinting (printing) by reactive dyeing.

Next, using the disperse dye printing method, an experiment of dyeing with the following paste (original paste) and dye was performed. The fixing includes high-pressure steaming (HT), high-temperature steaming (HT), and dry heat. In this example, the fixing was performed by high-temperature steaming (HT).
○ Paste (original paste)
The color density was compared between the original paste mainly composed of alginic acid and the CMC / gum-based / modified starch paste applied to general disperse dye printing.
○ Disperse dyes Three primary colors and Navy / Black dyes were selected in consideration of appropriateness such as color developability, bleed property, and contamination.
○ Concomitant auxiliary agent Dye accelerating agent / Dense dye pH adjuster Anti-reduction agent ○ Fixing by high-temperature steaming (HT) method Due to the low melting point that is a characteristic of polylactic acid fiber, 170 ℃, 2-5 minutes Teaming poses a great risk to the heat stability of the fiber.
Therefore, a printing test was conducted by setting the steaming (HT) temperature to 110 ° C. to 130 ° C. and changing the steaming (HT) time.

(1) Results for glue (original paste) The color developability of alginic acid original paste is low. The color developability of single and mixed products such as CMC, gum and processed starch paste was slightly improved, and there was no problem in acid adjustment.
(2) About disperse dye Under the above-mentioned conditions, there was a thing which lacked clarity and slightly bleeded. Furthermore, the dyed fabric had low light fastness and friction fastness. Furthermore, since the temperature in steaming (HT) was set low, the color density was remarkably lowered. In order to supplement the color density, I tried to use an infectious agent (urea / surfactant). Although a thick dye was tested, the steaming (HT) temperature was low, so there was no significant effect.
(3) Results for concomitant adjuvants Expected effects did not occur.
(4) Fixing property by high-temperature steaming (HT) method When treated at a steaming (HT) temperature of 130 ° C. and steaming (HT) time of 30 minutes, the texture was poor and the fabric contracted.
Similar results were obtained even at a steaming (HT) degree of 110 ° C. Then, when steaming (HT) time was shortened and performed in 15 minutes, both the texture and shrinkage were improved, and the fixing of the dye was improved.

  From the above test, when the disperse dye is used as the printing method for the polylactic acid fiber, the steaming (HT) temperature is 110 ° C. and the steaming (HT) time is within 15 minutes. It was found that the fastness is improved. In addition, the adjustment paste of alginic acid and the synthetic paste was easy to remove the paste, and the color development was improved.

  In this embodiment, the hand-printing method using a screen saddle has been described. However, even when a mechanical printing method such as inkjet, rotary, or auto-printing is used, the steaming (HT) temperature is 110 ° C. and steaming ( By setting the (HT) time to 15 minutes, similar improvements in dyeability, hue, and fastness are observed.

Illustration of textile printing process

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printing process 2 Steaming (HT) processing process 3 Water washing process 4 Feel adjustment process 5 Finishing process 6 Draw-out process

Claims (4)

A printing process in which polylactic acid fibers are printed with color paste prepared and mixed with paste and dye,
A steaming (HT) treatment step of treating the polylactic acid fiber printed in the above step in a hot and humid environment;
A water-washing process in which the color paste printed from the polylactic acid fiber is washed with water to remove the paste;
A texture adjustment process for adjusting polylactic acid fibers after washing,
Finishing process that dry heat-treats the polylactic acid fiber that has been subjected to texture adjustment,
Comprising at least
In the printing process, the color paste is prepared by adjusting and mixing at least an acrylic polymer, a natural paste, an ultraviolet cut agent, and a disperse dye,
In the steaming (HT) treatment process, a steaming (HT) environment is a temperature of about 110 ° C., a humidity of 75%, and a treatment time of 15 minutes or less.   2. The polylactic acid fiber printing method according to claim 1, wherein, in the water washing step, after the paste is removed with cold water, reduction washing is performed for about 20 minutes.   3. The printing method for polylactic acid fibers according to claim 1 or 2, wherein, in the texture adjusting step, the polylactic acid fibers after washing with water are immersed in an aqueous amino acid solution to impart moisture retention and lubricity. 4. The polylactic acid fiber printing method according to claim 1, wherein in the finishing step, a dry heat treatment is performed at a temperature of about 110 to 120 [deg.] C. for a treatment time of 30 to 50 seconds.

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