JPH07157957A - Production of antimicrobial nonwoven fabric comprising polyurethane elastic filament - Google Patents

Abstract

PURPOSE:To obtain antimicrobial nonwoven fabric comprising polyurethane elastic filaments having excellent thermal performance and to provide a method for producing the nonwoven fabric industrially and advantageously. CONSTITUTION:A molten thermoplastic polyurethane elastic material is mixed with a polyisocyanate compound and an antimicrobial agent and spun from fine holes to give filaments, which are sent by a high-speed air flow, sprayed, piled in a sheetlike state and collected to give a method for producing antimicrobial nonwoven fabric comprising polyurethane elastic filaments.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a nonwoven fabric composed of polyurethane elastic filaments,
More specifically, it relates to a method for producing an antibacterial non-woven fabric comprising a polyurethane elastic filament which is excellent in thermal performance by the melt blow method and can exhibit stable antibacterial performance for a long period of time.

[0002]

2. Description of the Related Art In recent years, the market for nonwoven fabrics has been expanding rapidly. Among them, the non-woven fabric produced by the melt blow method has softness,
Demand is rapidly increasing because it has drapeability and excellent filtration characteristics. On the other hand, even in such non-woven fabric fields, materials having higher performance and higher functionality are required. In particular, non-woven fabric having antibacterial properties can be applied to various fields, and therefore its development is strongly demanded.

Various non-woven fabrics having antibacterial properties have been proposed. For example, Japanese Patent Laid-Open No. 2-264
No. 078 proposes a non-woven fabric which exhibits a continuous anti-bacterial action by suppressing the growth of bacteria and Trichophyton by mixing fine particles of an anti-bacterial zeolite which is an inorganic compound between the fibers constituting the non-woven fabric. ing. In addition, JP-A-4-19
No. 4079 and Japanese Unexamined Patent Publication No. 4-272273 disclose antibacterial performance by adhering a composite consisting of a deacetylated compound of chitin and cellulose fine powder to a nonwoven fabric composed of long or short fibers of a thermoplastic polymer. Nonwoven fabrics having are proposed. However, these non-woven fabrics are non-woven fabrics composed of fibers having no rubber-like elasticity such as polyester, polyamide, or polyolefin. As a method for obtaining a nonwoven fabric from a polyurethane elastic body, for example, Japanese Patent Publication No. 59-223347,
A method for producing a polyurethane non-woven fabric by a melt blow method has been proposed. However, no consideration is given to the antibacterial performance of this nonwoven fabric. As described above, at present, no attempt has been made to impart antibacterial performance to the polyurethane elastic filament nonwoven fabric by the melt blow method.

[0004]

An object of the present invention is to provide an antibacterial non-woven fabric comprising polyurethane elastic filaments having excellent thermal performance, and another object is a method for industrially producing such non-woven fabric. To provide.

[0005]

The method for producing an antibacterial non-woven fabric of the present invention comprises a molten thermoplastic polyurethane elastic body,
It is characterized in that a polyisocyanate compound and an antibacterial agent are added, mixed and kneaded, and then filaments spun out from the pores are injected together with a high-speed air stream to be deposited and collected in a sheet form.

As the polyurethane elastic body applied to the present invention, a known segmented polyurethane is used.
Particularly, melt-spinnable thermoplastic polyurethane is suitable. Such a polyurethane elastic material has a molecular weight of 500 to 6
000 low melting point polyols such as dihydroxypolyether, dihydroxypolyester, dihydroxypolycarbonate, dihydroxypolyesteramide and organic diisocyanates having a molecular weight of 500 or less, such as P, P'-diphenylmethane diisocyanate, tolylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, It is a polymer obtained by reacting xylylene diisocyanate, 2,6-diisocyanate methyl caproate, hexamethylene diisocyanate and the like with a chain extender having a molecular weight of 500 or less, for example, glycol, amino alcohol or triol. Among these polymers, particularly preferable ones are polyurethanes using polytetramethylene glycol or poly ε-caprolactone as a polyol, or polybutylene adipate. As the organic diisocyanate, P, P'-diphenylmethane diisocyanate is suitable. P, P'-bishydroxyethoxybenzene and 1,4-butanediol are preferable as the chain extender.

The polyisocyanate compound used in the present invention is a compound having at least two isocyanate groups in the molecule and preferably has an average molecular weight of 400 or more. For example, the molecular weight used for the synthesis of polyurethane elastic body is It can be synthesized by reacting a polyol of 500 to 6000 with a double molar amount of an organic diisocyanate having a molecular weight of 500 or less. At this time, a compound having three or more hydroxyl groups may be used as the polyol. Further, an organic diisocyanate dimer is also used. Suitable polyisocyanate compounds include polytetramethylene glycol having a molecular weight of 500 to 2000 and having hydroxyl groups at both ends, polycaprolactone, or polybutylene adipate to which P, P'-diphenylmethane diisocyanate is added in a double mole. You can In the present invention, those containing 1 to 30% by weight of antibacterial agent are used.

The amount of the polyisocyanate compound containing the antibacterial agent added is 3 to 30% by weight based on the mixture of the polyisocyanate compound and the thermoplastic polyurethane elastic material.
Is preferred, and particularly preferably 5 to 20% by weight.

The addition amount varies depending on the type of polyisocyanate compound used, but if the addition amount is small, the improvement of the thermal performance of the intended polyurethane nonwoven fabric is insufficient. On the other hand, if the amount of addition is too large, uneven mixing, deterioration of yarn quality and the like are likely to occur, and spinning operability becomes unstable, which is not preferable.

As the antibacterial agent used in the present invention, an antibacterial agent which has heat resistance at the melting temperature of the polyurethane elastic body and does not react with the polyisocyanate compound is suitable. For example, zeolite fine particles having antibacterial properties or silver. Phosphate compounds supporting metal ions having antibacterial properties such as ions are used. In particular, the phosphate-based compounds supporting metal ions having antibacterial properties of silver ions have a three-dimensional network of each constituent ion, are very chemically and physically stable, and have a fine particle size. It is preferable because it can be easily obtained.

The average particle size of the antibacterial fine particles used in the present invention is preferably 0.1 to 2.5 μm, more preferably 0.3 to 1.0 μm, although it depends on the particle size distribution. When the average particle size of the fine particles is less than 0.1 μm, aggregation easily occurs, and uniform fine dispersion may be difficult even if a dispersing device and a dispersant are used. Further, if it exceeds 2.5 μm, even if a uniformly dispersed state is obtained, it is not preferable in consideration of fiber performance. Furthermore, if aggregated particles of 10 μm or more are present, the spinning filtration pressure rises in a short time and many yarn breakages occur, which is not preferable in operation.

As a method of incorporating the antibacterial agent into the polyisocyanate compound, it is possible to add the antibacterial agent and then disperse it after synthesizing the polyisocyanate compound, but the polyisocyanate compound is liable to be deteriorated by moisture in the air. Therefore, it is preferable to disperse the polyisocyanate compound before synthesis. For example, an antibacterial agent is added to a polyol, sufficiently dispersed by a stirring device such as a homomixer, coarse particles are removed by filtration or sedimentation if necessary, and then reacted with an organic diisocyanate compound to synthesize a compound.

The content of the antibacterial agent is preferably 1 to 30% by weight, and particularly preferably 5 to 20% by weight, based on the mixture of the polyisocyanate compound and the antibacterial agent. If the content exceeds 30% by weight, the fluidity of the polyisocyanate compound may decrease, and handling may be difficult. Further, if the content is less than 1% by weight, a large amount must be added, which is not preferable in the spinning operation.

The amount of the antibacterial agent according to the present invention added is preferably 0.1 to 5% by weight, and particularly preferably 0.2 to 5% by weight, based on the mixture of the thermoplastic polyurethane elastic material, the polyisocyanate compound and the antibacterial agent. It is 3% by weight. If the addition amount exceeds 5% by weight, the spinnability of the polyurethane elastic yarn is reduced, and a thick yarn or a shot is likely to occur during spinning. Further, if the addition amount is less than 0.1% by weight, antibacterial performance becomes insufficient.

The antibacterial non-woven fabric comprising the polyurethane elastic filaments of the present invention, the polyisocyanate compound added to the thermoplastic polyurethane elastic body and kneaded in the manufacturing process reacts after fiber formation to form a cross-linking bond.
It has completely different properties from the thermoplastic polyurethane elastic body used as a raw material, cannot be remelted, and is insoluble in solvents such as dimethylformamide or tetrahydrofuran at room temperature. Therefore, the nonwoven fabric of the present invention has high strength, excellent elongation recovery properties, and excellent thermal performance.

The polyisocyanate compound in the method of the present invention not only improves the physical properties of the resulting non-woven fabric, but also has the effect of lowering the melt viscosity of the polyurethane elastic body in the spinning process, so that the spinning temperature can be lowered. Therefore, it becomes easy to avoid thermal decomposition of the polyurethane elastic body, and the spinning operability is improved. Further, since the polyurethane elastic fibers deposited as the nonwoven fabric are likely to stick to each other, it becomes easy to firmly bond the nonwoven fabric by pressing the nonwoven fabric without using an adhesive or the like as described later.

The production of the nonwoven fabric of the present invention is carried out by a spinning apparatus equipped with a portion for melt-extruding a thermoplastic polyurethane elastic body, a portion for adding and mixing a polyisocyanate compound and an antibacterial agent mixture, and a spinning head for the nonwoven fabric. Is preferred. As such a spinning device, a known device used for adding a modifier during spinning can be used. As the spinning head for the non-woven fabric, a spinning head having a known shape can be used, but a spinning head having a nozzle for discharging a molten polymer and slits for jetting heated air on both sides thereof is particularly preferable. Such a spinning head is described, for example, in JP-B-41-7883, and a kneading device having a rotating portion in a portion where a mixture of a polyisocyanate compound and an antibacterial agent is added to and mixed with a polyurethane elastic body in a molten state. Although it is possible to use a mixing device, it is preferable to use a mixing device having a static kneading element which does not have a driving part and is simple in device. A known device can be used as the device having the static kneading element. The shape of the static kneading element and the number of elements vary depending on the conditions of use, but make sure that the polyurethane elastomer, polyisocyanate compound and antibacterial agent are sufficiently mixed before being discharged from the spinneret. Selection is essential. However,
Since the static kneading element tube is gradually blocked with a gel-like substance or the like after long-term use, it is preferable to use a kneading device having a rotating part in the case of continuous operation for a long period of one month or more. . In particular, it is preferable to use a mixing type extruder having a portion for melt-extruding the thermoplastic polyurethane elastic body, a portion for injecting a mixture of a polyisocyanate compound and an antibacterial agent, and a portion for mixing and kneading in the extruder.

An example of an embodiment of the present invention will be described below. Pellets of thermoplastic polyurethane elastic material are supplied from a hopper and heated and melted by an extruder. The melting temperature is 190.
The range of ~ 230 ° C is preferred. On the other hand, the polyisocyanate compound containing the antibacterial agent is 100 ° C in the supply tank.
Melt at the following temperature and defoam beforehand. If the melting temperature is too high, alteration of the polyisocyanate compound is likely to occur.
Temperatures between ° C are used as appropriate. A polyisocyanate compound containing a molten antibacterial agent is metered by a metering pump, optionally filtered by a filter, and added to the melted polyurethane elastic body at the association portion provided at the tip of the extruder. The polyisocyanate compound and the polyurethane elastic body are kneaded by a kneading device having a static kneading element. This mixture is metered by a metering pump and introduced into the spinning head. As the spinning head, an ordinary apparatus for spinning a non-woven fabric can be used, but it is preferable to design the spinning head to have a shape in which the retained portion of the mixture is as small as possible. If necessary, foreign substances are removed by a filter layer such as wire netting or glass beads in a filter layer provided in the spinning head, and then the mixture is discharged from a spinneret arranged in a row and jetted from a slit. Is drawn and collected on a moving net that is stretched and moved by If necessary, the web collected on the net is immediately pressed with a roller or the like and taken as a nonwoven fabric.

[0019]

The present invention will be described in detail with reference to the following examples. Unless otherwise specified, the terms [%] and [parts] in the examples mean [% by weight] and [parts by weight], respectively.

Example 1 600 parts of polytetramethylene glycol having a molecular weight of 850 was heated to 80 ° C. to obtain the phosphate antibacterial agent Novalon AG-3.
00 (Toa Gosei Chemical Industry Co., Ltd., average particle size 0.5μ)
m) 30 parts were added, and the mixture was stirred with a homomixer for 3 hours to disperse. After decompressing this mixture to remove water, P,
370 parts of P'-diphenylmethane diisocyanate was added, and the mixture was heated and reacted at 80 ° C. for 30 minutes with gentle stirring in a nitrogen stream to obtain a polyisocyanate compound containing 3% of novalon.

Further, by the same method, novalon was added to 0%,
Polyisocyanate compounds containing 7%, 15% and 25% were prepared in different supply tanks.

The polyisocyanate compound containing the zeolitic antibacterial agent Bactekilar (manufactured by Kanebo Co., Ltd.) was adjusted to 3%, 7%, 15% and 25% by the same method as for the novalon-containing polyisocyanate compound.

On the other hand, polytetramethylene glycol having a molecular weight of 1000 is used as a soft segment, P, P'-diphenylmethane diisocyanate is used as a diisocyanate compound, and P, P'-bishydroxyethoxybenzene is used as a chain extender to polymerize the thermoplastic polymer. Polyurethane elastic pellets were obtained.

Using the polyurethane elastic pellets thus obtained and the antibacterial agent-containing polyisocyanate compound as raw materials, the antibacterial agent-containing polyisocyanate compound supply device and an extruder equipped with a kneading section consisting of a static kneading element are arranged in a line. A non-woven fabric was manufactured using a spinning head having slits for jetting heated air on both sides of a hollow nozzle.

The amount of polyisocyanate compound is in the range of 10% to 13% with respect to the mixture of the thermoplastic polyurethane elastic material and the polyisocyanate compound, and the antibacterial performance and the spinning condition when the contents of Novalon and Bactekiller are changed. The results are shown in Table 1.

[0026]

[Table 1]

The antibacterial performance was obtained by adding 1.5 g of a non-woven fabric with a buffer solution of Staphylococcus aureus or Klebsiella pneumoniae to 150 in a closed container.
The viable cell count was measured after shaking for 1 hour at a rate of 1 minute / minute, and evaluated as shown in Table 2 by the rate of decrease with respect to the bacterial count of the added suspension.

[0028]

[Table 2]

As is clear from Table 1, the antibacterial agent-containing nonwoven fabric obtained by the method of the present invention has excellent antibacterial performance. Those containing 3.3% of Bactekiller had an unstable spinning condition, and shots tended to be mixed.

Example 2 Polyurethane elastic pellets used in Example 1 and
Using a polyisocyanate compound containing 3%, 7%, and 15% of Novalon as a raw material and using the same apparatus and method as in Example 1, non-woven fabrics having different amounts of polyisocyanate compound added were produced. The results are shown in Table 3.

[0031]

[Table 3]

The 130.degree. C. heat setting rate is the setting rate when a 100% stretched sample is left for 10 minutes in a constant temperature room at 130.degree. The smaller this value, the better the heat resistance.

As is clear from Table 3, the nonwoven fabric obtained by the method of the present invention has excellent antibacterial properties and further improved heat resistance.

Example 3 A nonwoven fabric was produced in the same manner as in Example 1 except that the kneading section consisting of static kneading elements was changed to a kneading apparatus having a rotating section. The antibacterial performance is the same level as in Example 1,
The spinning condition was good, and long-term continuous operation for 4 to 6 months was possible (in Example 1, the kneading section needs to be replaced after about 1 month).

[0035]

Since the antibacterial non-woven fabric obtained by the method of the present invention is composed of polyurethane elastic filaments, the non-woven fabric of the present invention alone has not only softness, drapeability and filtration properties but also excellent stretch recovery property. Or by combining with various materials, etc., food field, medical field,
Or in the field of industrial materials, various filters, various packaging materials, bedding, clothing, diapers, sanitary items, towels, masks, insoles, sportswear, various sports items,
It can be widely used for various purposes such as bandages and bansoko.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location D04H 3/03 A 7199-3B

Claims (3)

[Claims] 1. A polyisocyanate compound and an antibacterial agent are added to a molten thermoplastic polyurethane elastic body, and after mixing and kneading, filaments spun from the pores are jetted together with a high-speed air stream, and deposited in a sheet form. A method for producing an antibacterial non-woven fabric comprising a polyurethane elastic filament, which is characterized in that it is collected. 2. The method according to claim 1, wherein the antibacterial agent is a phosphate compound supporting silver ions. 3. The method according to claim 1, wherein a kneading device having a rotating portion is used for the mixing and kneading.