JPH01201582A - Surface-active polyester fibrous structure and production thereof - Google Patents

Abstract

PURPOSE:To obtain the title fibrous structure by graft polymerization to the surface layer of a polyester fiber a monomer with electron beam irradiation followed by etching said surface layer by a low-temperature plasma treatment to expose the graft-polymerized portion on said surface layer. CONSTITUTION:A polyester fibrous structure is treated with a swelling agent (e.g., chlorinated hydrocarbon such as dichloromethane) and dipped in a mono mer solution such as of unsaturated carboxylic acid, its anhydride or its acid amide); alternatively, said structure is dipped in said monomer solution in the presence of said swelling agent. Subsequently, to the above process, the resultant system is irradiated with electron beams to perform graft polymerization followed by washing with a weak alkaline solution to remove the homopolymer on the surface of said structure. Said surface is then subjected to low- temperature plasma treatment followed by etching to highly expose the graft- polymerized portion and at chemically modify said surface to form asperities thereon, thus obtaining the objective surface-active polyester fibrous structure, which will effectively applicable to such fields as medicine, biotechnology and filter membrane material.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a polyester fiber structure and a method for producing the same, and particularly to a surface-active polyester fiber structure and a method for producing the same.

(Prior Art) Polyester fibers are now at their peak as materials for clothing, industrial materials, and the like. It has also been found that they are suitable for special fields such as medical materials, such as artificial blood vessels. The reason for this is that it has superior mechanical and chemical properties6, but on the other hand, it has poor hydrophilicity, so it has disadvantages such as lack of hygroscopicity and water absorption, and being easily charged and dirty. Research to improve this problem has continued since the invention of polyester fibers.

The reason for the poor n1 aqueous property is that the polyester polymer is
This is said to be due to the highly crystalline molecular structure that prevents water from entering, and the lack of functional groups that prevents water from being adsorbed.

In order to improve these drawbacks, the following methods have been used in the past.

(1) Blending second and third polymer components that disrupt high crystallinity or adding components having functional groups is done at the spinning stage.

(2) Although the principle is completely different from this, it is also possible to make it easier for water to absorb and enter at the spinning stage by adding irregularities to the fiber surface or making continuous holes in the fiber. This is done through a combination of subsequent dyeing processes, etc.

(3) As a treatment after the spinning step, it is also possible to graft polymerize a monomer having a functional group to make it hydrophilic.

(4) A hydrophilic agent based on a surfactant or a hydrophilic agent based on a resin component can also be applied.

(Problems to be Solved by the Invention) However, the methods (1) and (2) are methods applied at the spinning stage, and cannot be said to be flexible means.

In addition, in method (3), hydrophilicity cannot be exhibited only by the usual grafting method unless the graft polymerization type is 1 or more, and in this case, the inherent mechanical properties of the polyester are inevitably degraded.

Furthermore, it goes without saying that method (4) is unreasonable in terms of durability.

Therefore, the present invention solves the above-mentioned problems, and provides a method for producing polyester fibers that are durable, have hydrophilic properties, antistatic properties, etc. without changing the original properties of polyester, and that can be manufactured by this method. Our aim is to provide a fiber structure made of fibers.

(Means for Solving the Problems) In order to solve the above problems, in the present invention, polyester fibers are immersed in a monomer solution treated with a swelling agent or in a monomer solution in the coexistence of a swelling agent, and then irradiated with ionizing radiation. Then, the surface homopolymer is removed by washing with a weak alkaline solution, etching is performed by low-temperature plasma discharge treatment to highly expose the graft polymerization, and at the same time, chemically modified irregularities are created. A surface active polyester fiber structure ITA is made.

(Function) The polyester-based UN tlt in the present invention refers to a fiber made of a polymer whose main structural unit is ethylene terephthalate, and a matting agent, anti-discoloration agent, dye, etc. may be added if necessary.

Moreover, the fiber structure as used in the present invention only needs to be a polyester fiber material, and its form is not restricted. Examples include monofilament, tow, stable, cotton, yarn, fabric (&i l! material, non-woven fabric), and the like. If a uniform treatment effect is desired in the present invention, it is most effective to perform the treatment when the constituent single yarns are separated, such as monofilament, stable, and cotton. When it becomes thread-like, woven, or knitted, the single threads become thinner, and furthermore, these threads intersect, resulting in a loss of uniformity. Generally, polyester fibers are obtained by melt spinning, and the spinning process involves three steps: extrusion from a nozzle, solidification, stretching, and heating and heat setting, but the treatment of the present invention can be performed after any step. 0 The treatment of the present invention consists of both graph 1 - polymerization treatment and plasma treatment, but the former must always take precedence.

First, the graft polymerization treatment will be explained. Graft polymerization means ``grafting'' and is an attempt to supplement the properties that the main stem lacks by grafting onto the branches. In this case, the polyester fiber is the main fiber, and the branches are polymers produced from monomers. As "grafting" means,
The master and technique are combined into one body. In this way, supplementing 1 by grafting which is not present in the main stem is useful as a method other than spinning.

Now, polyester ill In has a glass transition temperature of 5
It has within the range of 0°C to 80°C. In order to carry out graft polymerization easily and efficiently, it is best to carry out the graft polymerization in a temperature range above this glass transition temperature.However, the temperature at which the graft polymerization is carried out may be set within this temperature range; This chemical has the advantage of lowering the glass transition temperature and can be carried out at lower temperatures. This lower temperature consumes energy,
It is also advantageous in terms of ease of work. However, it goes without saying that the combination of a temperature higher than the glass transition temperature and a swelling agent increases the effect to the nth power. Examples of swelling agents include dichloromethane, 1.1-dichloroethane, 1.2-dichloroethane, 1,2-dichloroethylene, 1,1.2-)
-dichloroethane, trichlorethylene, 1.1,1.
Chlorinated hydrocarbons such as 2-tetrachloroethane, 1.1,2.2-tetrachloroethane, 1.1.2.2-tetrachloroethane, monochlorobenzene, dichlorobenzene, and trichlorobenzene are preferred. As a monomer,
Either an unsaturated carboxylic acid, an unsaturated carboxylic acid anhydride or an unsaturated carboxylic acid amide must be used as a component. For example, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, unsaturated carboxylic anhydrides such as maleic anhydride, itaconic anhydride, unsaturated acids such as acrylamide, methacrylamide, etc. There are carboxylic acid amides, and these are used alone or in combination of two or more. Furthermore, acrylonitrile,
A method in which dipping treatment is performed with a swelling agent alone, which may be co-graft polymerized with vinyl pyrrolidone, vinyl chloride, etc., followed by dipping treatment with a monomer alone; and a method in which a dipping treatment is performed in a mixed bath of an MD5 lubricant and a monomer. The effect remains the same no matter what. Swelling agents may be diluted with water, surfactants, etc., but processing from a bath containing 100% swelling agent is not recommended from the standpoint of equipment and recovery. It's advantageous. In the treatment with a lubricant, the degree of swelling can be adjusted by adjusting the immersion temperature and immersion time. This moisturizing effect differs depending on the state of the crystal structure of polynisder, which is the material to be treated. The solidified state extruded from Nosuru has the least amount of crystalline structure and exhibits the greatest swelling most easily.
As the process progresses, it becomes a region with more crystalline structure, and the swelling becomes difficult and small. In the present invention, even if the L5j moisture is large, it does not lead to good results.

In order to distribute the graft polymer at high density in the epidermal layer, to put it in an extreme way, only the epidermal layer needs to be swollen. However, this kind of swelling control is nearly impossible;
The swelling agent, its concentration, immersion temperature, immersion time, etc. are adjusted so as to approach this value.

When treating with a swelling agent, the temperature is 0°C to 80°C when the swelling agent is 100%.
C. for 30 seconds to 180 minutes, and then the swelling agent is removed by normal pressure or vacuum drying at 120.degree. C. or lower. Using a higher temperature than this will lead to a reduction in the swollen area due to the heat treatment effect.

When a swelling agent and a monomer are used in a mixed bath, their compatibility must be confirmed. Perfectly compatible state! This is because it is difficult to apply it uniformly unless it is used in a vacuum.

Dilution with water, organic acids, etc. is possible as long as this compatibility allows. In some cases, chemicals that inhibit homovolimerization (for example, metal salts such as copper sulfate and copper chloride) may be added.

The concentration of monomer in this mixed bath depends on the desired grafting groups, but ranges from 10 to 90 volumes 1% 1-
In the present invention, it is also possible to apply the monomer only from the monomer bath, but it is possible to apply the monomer only from the monomer bath.
To do this, it is preferable to use one of the two methods shown above.

Immersion in a monomer bath or a mixed bath of a swelling agent and a monomer takes a sufficient amount of time while stirring the solution in the liquid or agitating the object in order to uniformly apply the monomer. Needless to say, the immersion temperature and immersion time are adjusted in this case as well.Items that have already been treated with a swelling agent allow the monomer to penetrate easily, and immersion in the monomer bath only takes a short time. The appropriate temperature is 10℃~
The temperature is 80°C, and the time can be set from 5 seconds to 30 minutes.

Immersion in the mixed bath of the swelling agent and monomer is carried out in the same manner as the treatment with the swelling agent described above.

The treated object has sufficiently absorbed the monomer, but the next step is coulometric radiation!
((It must be ensured that it does not evaporate into the air.

A good way to do this is to provide an excess amount of the above treatment FJ solution or to make the irradiation reaction chamber smaller. As the ionizing radiation, electron beam irradiation obtained by an industrially widespread accelerator is necessary to achieve the present invention. If another energy source is used, the graph 1-Th suitable for the purpose of the present invention cannot be obtained due to insufficient energy.

For irradiation, it is preferable to use an electron beam (accelerator) with an energy of 01 to 5 MeV in a nitrogen gas atmosphere, and the dose rate is 1.0.
X10'' rad/sec to 1.0X10' rad/sec is used, and the irradiation dose is preferably 0.1 to 10 megarats.

The monomer solution is completely solidified on the liquid treated material by irradiation, and the reaction in graph 1 is completed.

In such a grafting reaction, the simultaneous progress of homobolimerization cannot be avoided, and the resulting homobomerization product must be dissolved and removed. A weak alkaline solution is used for this. Alkali can be defined as a substance that takes the form of hydroxide MOH and dissolves in water.

In this case, M refers to alkali metals and ammonium salts, but in a broader sense it also includes sodium carbonate, sodium bicarbonate, ammonium carbonate, sodium phosphate, etc. Here, the purpose of the weakly alkaline solution is to dissolve and remove the above-mentioned homopolymer, and there is no particular limitation as long as the aqueous solution has a concentration that achieves this purpose. .1 to 1% aqueous solution in a bath ratio of 1:
100-200 at a temperature of 40℃-80℃
Finish by doing ~20 minutes of processing 0 then 100
Dry in an atmosphere of ~200"C, and in some cases heat treatment at the same time. If you measure the mm here, you will see an increase in weight compared to before the graft treatment!fX1t, and this increase corresponds to the graft polymer. The increase due to this polymer is shown as the grafting rate, which is 0.2 to 15 percent or 0.44 to 7 percent.

The graft polymer to polyester obtained in this way does not appear on the surface of the polyester, but has the highest density slightly inside the outer skin, called the skin layer, and gradually becomes less dense toward the center. The similar distribution can be confirmed by a combination of alkaline hydrolysis method and coloring method.

A detailed explanation of these is as follows.

When a polyester fiber is cut perpendicular to the fiber axis, a cross section appears. This cross section may be circular or have a specific shape. To make the explanation easier to understand, assume that the cross section is circular. The outer periphery of this cross section, that is, the outer skin, is the part that is in contact with the outside air, and is the part that comes into contact first during swelling agent treatment or monomer treatment. On the other hand, the center of the cross section is the part farthest from this, and the part that comes into contact with them is the slowest. From this, the probability that monomers will be adsorbed and their graft polymerization will occur can be considered to be approximately equal in concentric circles on the cross section centered on the center of the cross section. Polyester fibers have the unique property that their outer skin is uniformly dissolved by alkaline hydrolysis, and can be easily made thin while maintaining their original shape. On the other hand, in the graft polymer, -C0OH is present as a functional group. This is an anionic group, which utilizes the reaction of stationary bonding with a cationic dye to detect the presence of a graft polymer and its effect on all
It is possible to determine Specifically, measurements using cationic dyes include color index number, 1% by weight of basic violet 10 and +'il diacid (80%).
in a bath containing 0.5 cc/L at a bath ratio of 1:200.
After coloring at 90°C for 20 minutes, wash twice at 60°C for 10 minutes with an acetic acid (80%) 0.5σ/L aqueous solution, then wash with water and dry. If it develops a violet color, it indicates the presence of a graft polymer, and the concentration can be measured with a spectrophotometer, and the L of the graft polymer can be estimated from the correlation with the grafting rate.6 Examples of the present invention Based on the data shown, polyester fiber!
It has been recognized that when the distribution is shown in a plane cut to pass through the center of the fiber parallel to the fiber axis of 1, it is almost 0-shaped to V-shaped.

Next, low temperature plasma discharge treatment will be explained.

Low-temperature plasma is one in which a strong electric field is applied to a gas under low pressure to cause a discharge. Here, inorganic gases such as air, carbon oxide, carbon dioxide, oxygen, nitrogen, hydrogen, argon, and helium are used as the gas. Among these, three types are often used: air, oxygen, and argon. Discharge treatment is performed by placing the object to be treated in this discharged field. This creates irregularities on the surface (this is called etching), and it is known that the size and depth of these irregularities vary depending on the gas used.

The size of the unevenness caused by the low-temperature plasma discharge treatment is minute. The method of displaying the size and depth of this unevenness is as follows. In other words, the average plane distance from a concave part to the lowest point of the next adjacent concave part, or the average plane distance from a convex part to the highest point of the next adjacent convex part, and the distance between the highest point of the convex part and the lowest point of the four parts. Both the average distance and depth are displayed. In order to indicate how many unevennesses exist, the number of unevennesses per unit area, that is, the density, is displayed. In the present invention, the size and depth of the unevenness are not directly important factors, but are described because they are numerical values obtained as a result, and these are counted from the photograph obtained from the SEM.

In addition to the formation of this unevenness, it is also known that chemical changes occur on the surface (this is called chemical modification), which is caused by the atoms of the gas used and the atoms of the material to be treated. One theory is that a new reaction takes place on the surface under plasma discharge treatment, and the other theory that when taken out into the air after plasma discharge treatment, reactions occur between active radicals and oxygen, carbon dioxide, water, etc. in the air. However, in the case of the present invention, no reliable proof has been made.In any case, these products act like part of the functional group and do not promote the adsorption of water molecules, but improve hydrophilicity and adhesion. This leads to improved sexual performance, etc. This will be referred to as a chemical modification effect.

The conditions for the low temperature plasma discharge treatment of the present invention are as follows: frequency: 100KH, ~10MH;
~100MH, preferably 110 to 11. A low frequency discharge plasma of 13.56 MI (□) is good, and the output is 10 W to 100 KW, the pressure is 2 torr or less, the gas flow rate is 10 to 300 ml/+ain, and the processing time is 5 seconds to 1800 seconds.The pressure is The low pressure side is effective because it increases the momentum of the gas atoms, but if you increase the gas flow rate, the pressure will inevitably become high pressure side, so if the gas flow rate exceeds a certain level, it will not be possible to make the pressure the desired low pressure. Specifically, under 0.051 Torr, the gas flow M is less than 20 mf/ff1in, under 0.1 Torr, it is 20 to 100+al/sin, and under 0.2 Torr, it is 40 to 200 mA'/+nin. That's how it is.

As mentioned above, polyester fibers belong to highly crystalline polymers and are not easily etched. However, chemical changes (chemical modifications) can be applied. This is a feature of low-temperature plasma discharge treatment.

The present invention focuses on etching, and it is interpreted that chemical changes (chemical modification) are inevitably imparted as a side effect. Now the frequency is 13.56M
By setting H, and changing output, pressure, gas flow rate, etc., the optimum conditions can naturally be found. Among these, the output is important. 10 ways to get the etching effect
0W or more, preferably 300W or more is required; if it is less than this, unevenness will not be created, or even if it does occur, it will take a long time.

Finally, polyester fibers are obtained through the processes of fluid extrusion from a nozzle, stretching, and heat setting. After this process, processes such as twisting and adding bulkiness are added. The fiber m obtained in this way has more chances to undergo heat treatment later on, and the properties of the fibers t and +i gradually change. In the solidified state of fluid extrusion from the nozzle, the first stage that has just formed a fibrous form is... It has a low crystallinity ratio and is easy to process.

However, by stretching, the crystallinity increases at once,
It is known that polyester fiber exhibits general polyester fiber performance. Based on these facts, low-temperature plasma radiation, 1. It is a good idea to process the material in a state that is easy to process.

In the present invention, emphasis is placed on the production of polyester fibers tailored to the purpose of Z and k. Chemistry of polyester 11!
J1. When making use of Y sexual thoughts, it is not necessarily necessary to add mechanical properties to j1 at the same time.

(Example) Next, examples will be shown.

Approximately 2 grams of polyester monofilament with an apparent Young's modulus of 120 kg/mm2 and a diameter of 40 microns (strength 100 g, elongation 40%) was prepared, thoroughly washed in hot water containing a nonionic surfactant, washed with water, dried, and weighed. did. This Young's modulus of 6a is generally said to be 1 1 for polyester fibers.
00 kg/+n+n2.

Below, the following processing was performed.

(1) Swelling agent 100% I bath treatment 1.2-dichloroethane (commercial reagent grade) was set at 20°C and 40°C,
The object to be treated is immersed in this solution for 1 hour while stirring.

The fibers are then taken out and left at room temperature for a day and night to remove dichloromethane adhering to the surface, and are further dried at 80° C. for 600 minutes to remove 1,2-dichloroethane adsorbed inside the fibers. Let each sample be a group A sample and a group B sample.

(II) Samples of groups A and B obtained by monomer bath treatment (+) were immersed and stirred in methacrylic acid (commercially available reagent) at 40° C. for 1 hour.

(III) A mixed solution of 1,2-dichloroethane (commercially available dichloroethane) and methacrylic acid (7F7 version reagent) blended at a treatment volume ratio of 6=4 in a 155 lubricant/monomer mixture bath was mixed at 50%
℃, and the object to be treated was immersed therein for 2 hours at 11°C. This is designated as the 0 group sample.

(IV) A treated with (n), Bngil
The 0 group samples treated with (Ill) were each transferred onto a stainless steel pallet, immersed in a treatment solution 5 times the weight of the dough, covered with a vinyl film, and the air replaced with nitrogen gas.

(V) Irradiation was performed using a Van de Graaf electron beam irradiation device, 1.5 MeV, 50 mA, 0.17 M rad.
The total line speed was 6 Mrad per second.

(Vl) Washing) Sodium carbonate ice water 10 ii/
The mixture was heated twice at 80°C for 20 minutes using L aqueous solution.

(■) The weight of each sample after drying at 100° C. for 60 minutes using a hot air dryer was measured, and the grafting ratio was calculated for each sample.

A Liver; 4, 3% r3 J+'T; 4
, 7% Group 0; 465%. These samples were colored with the above-mentioned Basic Baylet I/10 aqueous solution, but the color was very pale and it was difficult to determine that a graft polymer was present on the surface. Ta. In addition, these samples were subjected to the same alkaline hydrolysis treatment f1 (sodium carbonate 10 g/L aqueous solution, bath ratio 1:20010).
After 15 minutes at 0° C. for 30, 45, and 60 minutes, the amount of weight loss accompanying this was measured and colored with an aqueous solution of Basic Vilet 10. In this coloration, the coloration of all the samples was the darkest in the samples treated with alkaline hydrolysis for 15 minutes and 30 minutes, and it was determined that the graft polymer was exposed and present. That is,
When calculating the location of this location from the surface based on the weight loss rate at this time, it was found that it was a concentric circle extending 0.15 to 0.2 microns from the surface toward the center of the fiber axis. A schematic diagram of this distribution state is shown in Figure 1.

From this, in order to expose the polyester graft polymer obtained in the present invention on the surface in contact with the outside air, the amount of 0.1
It has been found that it is necessary to perform low-temperature plasma discharge treatment without etching down to 5 to 2 microns. This is a value of 1 to 2.5% in terms of weight loss rate of fIk.

(■) These trials 1'4 were set at a frequency of 13.56 MI [z,
Irradiation treatment was performed for 2 minutes and 4 minutes under the conditions of an output cuff of 00W, a pressure of 0.21-L, and an oxygen gas flow rate of 190 tJ/rain. When the sample thus obtained was colored with the aqueous solution of Basic Bioref 1 to 10 described above, a clear color reaction could be seen (graph 1 (indicating exposure of polymer)).

(IX) In addition, these test 1:1 SEM images were taken on the 0111 side and the tip of the fiber, and unevenness was created on both sides, and the size was 0.08 to 1. More than 90% of the ponds were 2 micron larvae, and around 10% were 1.8 to 3.0 micron giant ones. Depth is 0.
It was 0.06 to 1.0 microns.

(X) These samples showed immediate diffusion or good wetting when a drop of water was allowed to fall on their surface. i,
The rM friction charge voltage was measured with a rotary static tester (Koa Shokai) at a temperature of 20'C and a humidity of 40% after 2 minutes of rubbing against a cotton cloth, and each was 100 V or less.

(edited) The strength and elongation are 3% lower than untreated.
The elongation was improved by 4%.

(Effects of the Invention) From the results shown in the examples above, as described in the description of the present invention, monomers are graft-polymerized onto the skin layer of polyester fibers by electron beam irradiation, and then the skin layer is formed by low-temperature plasma discharge treatment. I learned that when removed by etching, the graft polymerized portion is exposed on the epidermal layer, and at the same time, it is possible to create a unique surface-active polyester fiber that creates decorated irregularities on the surface.

In addition, it retains the original polyester performance without deterioration of mechanical properties obtained by the present invention, has hydrophilicity due to the graft polymer arranged at high density on its surface, and has chemically modified minute irregularities added. The resulting so-called surface-active polyester fiber structure can be effectively applied to the medical field, biotechnology field, filter membrane material, etc.

[Brief explanation of the drawing]

No. 11A is a schematic diagram of the presence of graft polymers on a cross section taken from a polyester/graft copolymer fiber t obtained in the present invention and cut in the axial direction passing through the fiber axis. Here, 1> Center of single yarn 2) Outer skin surface of 'it yarn 3) Graft polymer distribution layer 4) Highest density layer of graft polymer 5) Jl to be removed by etching 6) New outer skin surface after etching .

Claims (2)

[Claims] (1) Polyester fibers are immersed in a monomer solution after treatment with a swelling agent, or immersed in a monomer solution in the presence of a swelling agent, and irradiated with ionizing radiation to perform a graft polymerization reaction,
Next, the surface homopolymer is removed by washing with a weak alkaline solution, and the graft polymerized portion is exposed to a high degree by etching by low-temperature plasma discharge treatment, and at the same time, chemically modified irregularities are created. A method for producing a graft copolymer fiber structure. (2) Polyester fibers are immersed in a monomer solution after treatment with a swelling agent, or immersed in a monomer solution in the presence of a swelling agent, irradiated with ionizing radiation to perform a graft polymerization reaction, and then washed with a weak alkaline solution. A surface-active polyester fiber structure formed by removing the surface homopolymer, etching with low-temperature plasma discharge treatment to highly expose graft polymerization, and at the same time creating chemically modified irregularities.