JP2006249615A - Antimicrobial nonwoven fabric and its application - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonwoven fabric having excellent flexibility and antimicrobial properties, also having excellent effects of hardly reducing the antimicrobial effects even after a long-time use, and utilizable for applications such as sanitary goods, medical supplies and clothing goods, more precisely, the nonwoven fabric of a polyolefin, having excellent flexibility, excellent antimicrobial properties and their persistence. <P>SOLUTION: The nonwoven fabric is obtained by forming a composition obtained by mixing 0.1-5.0 pts.mass nonionic surfactant for imparting hydrophilicity and 0.1-3.0 pts.mass zinc oxide-based antimicrobial agent with 100 pts.mass polyolefin by a spunbond method or a melt-blown method. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a nonwoven fabric formed by mixing a polyolefin with a specific antibacterial agent and a nonionic surfactant that imparts hydrophilicity.

  The demand for molded articles imparted with antibacterial properties is increasing. Antibacterial molded products are manufactured by adding an antibacterial agent to a polymer and molding it, but a molded product obtained by simply adding an antibacterial agent to a polymer has some antibacterial properties, but has a small antibacterial effect. In addition, an antibacterial agent and a compound that imparts hydrophilicity are combined because they lose their effect during use.

  For example, in a polyester, a composition of a combination of a polyester, an antibacterial agent, and a compound imparting hydrophilicity is known (Patent Document 1). However, when polyester is used as a fiber, there are problems such as poor flexibility. Therefore, in the case of making fibers, it is desired to impart antibacterial properties to polyolefins having excellent flexibility, but in particular, in the field of nonwoven fabrics, polyolefin nonwoven fabrics that have effective antibacterial properties are not known, There is a need to develop a nonwoven fabric made of polyolefin that has excellent antibacterial properties and can maintain antibacterial properties for a long time.

  On the other hand, in order to impart antibacterial properties to the nonwoven fabric, simply kneading the antibacterial agent into the raw material resin not only does not exhibit antibacterial properties, but also has problems such as reducing the mechanical strength of the nonwoven fabric. In addition, a nonwoven fabric obtained by applying lactic acid or the like as an antibacterial promoting material to a nonwoven fabric obtained by molding a mixture of polypropylene and aliphatic glyceride as a compound imparting hydrophilicity is known (Patent Document 2). Further, there has been proposed a polyolefin nonwoven fabric in which an inorganic antibacterial agent made of a specific metal, which is an antibacterial agent having superior antibacterial properties and durability, is kneaded into a raw material resin (Patent Document 3).

Although these antibacterial nonwoven fabrics are considerably excellent, there is a problem that the nonwoven fabric of Patent Document 2 cannot withstand repeated use. Moreover, the nonwoven fabric of patent document 3 is still inadequate at the point of antibacterial property and its sustainability. In order to obtain a polyolefin nonwoven fabric with more antibacterial properties and its durability, even if the method of Patent Document 1 is simply applied to the polyolefin nonwoven fabric of Patent Document 3, the dispersion is poor and the properties of the polyolefin are poor.
JP-A-11-166108 Special table 2003-500556 gazette JP 2003-166156 A

  An object of the present invention is to provide a polyolefin nonwoven fabric having excellent flexibility and antibacterial properties and durability.

  The present inventors have intensively studied to solve the above-mentioned problems, and by forming a composition having a specific composition by a specific molding method into a nonwoven fabric, a polyolefin exhibiting excellent antibacterial properties over a long period of time The present invention was completed by finding that a nonwoven fabric can be obtained.

  That is, the present invention mixes 0.1 to 5.0 parts by weight of a nonionic surfactant that imparts hydrophilicity to 100 parts by weight of polyolefin and 0.1 to 3.0 parts by weight of a zinc oxide antibacterial agent. A nonwoven fabric formed by molding the composition obtained by the spunbond method or the melt blown method.

  The present invention is also a hygiene product, a medical product and a clothing product using the nonwoven fabric.

  The nonwoven fabric of the present invention is excellent in flexibility and antibacterial properties and has an excellent effect that the antibacterial effect is not lost even if used for a long time, and is used for applications such as hygiene products, medical supplies, clothing supplies, etc. It is possible and very valuable industrially.

Hereinafter, embodiments of the present invention will be described.
The raw material composition for forming the constituent fibers of the nonwoven fabric of the present invention contains a polyolefin as a main component, a surfactant, and an antibacterial agent.

  Although it does not specifically limit as polyolefin used by this invention, Generally, olefins, such as ethylene, propylene, 1-butene, pentene, hexene, 4-methyl-1- pentene, vinyl acetate, etc. Those having as a main component a polymer of a vinyl monomer and a copolymer thereof are preferred. Specifically, polyethylene resins such as low density polyethylene, linear low density polyethylene (ethylene-α-olefin copolymer), medium density polyethylene, and high density polyethylene, polypropylene resins such as polypropylene and ethylene-propylene copolymer, Examples include poly-4-methylpentene, polybutene, ethylene-vinyl acetate copolymer, ethylene-butene copolymer, and mixtures thereof. These polyolefins may be produced using a Ziegler catalyst or may be produced using a single site catalyst such as a metallocene catalyst.

  Among these, a polypropylene resin is more preferable, and a homopolymer of propylene or a copolymer of propylene as a main monomer component and at least one other α-olefin is more preferable. Examples of other α-olefins include ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene and the like having 2 to 20, preferably 2 to 8 carbon atoms. -Olefin can be mentioned. These homopolymers or copolymers of propylene can be used singly or in combination of two or more.

  Various types of these polyolefins are commercially available, and may be appropriately selected depending on the application.

  The surfactant used in the present invention is a nonionic surfactant that imparts hydrophilicity. A nonionic surfactant is a surfactant that does not have a group that ionizes in an aqueous solution, and is a compound having a structure composed of a hydrophilic block and a hydrophobic block. Here, “giving hydrophilicity” means improving the hydrophilicity of the resulting nonwoven fabric by including the surfactant in the raw material composition, as compared with the case where at least the surfactant is not included. Means.

  In the present invention, the antibacterial activity of the antibacterial agent can be made excellent by using a nonionic surfactant that imparts hydrophilicity in combination with the antibacterial agent described later, and the antibacterial activity is improved. It can be maintained for a long time.

Any hydrophilic block may be used as long as the block is hydrophilic, such as a polyalkylene oxide such as polymethylene oxide, polyethylene oxide or a copolymer thereof, which is hydrophilic as a polymer. Or a molecular chain having a high density of hydrophilic groups such as —OH group, —CONH ₂ group, and —COOH group, for example, a polymer of a hydrophilic monomer having a hydrophilic group as described above, specifically, Examples include vinyl alcohol polymers, acrylamide polymers, and acrylic acid polymers. Of these, polyalkylene oxide is preferable, and polyethylene oxide or a copolymer thereof is particularly preferable.

  Examples of the hydrophobic block include hydrocarbon compound chains such as polymethylene, polyolefin, and polystyrene. Among them, polyalkylene such as polymethylene and polyolefin are preferable. That is, the nonionic surfactant that imparts hydrophilicity preferably has a structure composed of a polyalkylene group and a polyalkylene oxide group.

  The bonding method of the hydrophilic block and the hydrophobic block includes (1) a method of bonding a compound having an OH group to at least one terminal of a hydrocarbon chain and a polyalkylene oxide by an ether bond, and (2) a terminal. Examples include a method of copolymerizing a polyolefin having an epoxy group and an alkylene oxide, and (3) a method of copolymerizing a polyolefin having a vinyl group at the terminal and a hydrophilic monomer. is not.

  Preferred surfactants include those in which a polyethylene glycol chain is bonded to an optionally branched polymethylene chain with an ether bond, and the terminal is —OH.

  The ratio between the hydrophilic block and the hydrophobic block is not particularly limited as long as hydrophilicity can be imparted to the nonwoven fabric. However, the molecular weight ratio is generally about 5:95 to 95: 5. .

  Among these, when considering that it is easy to mix with polyolefin, and that the obtained nonwoven fabric maintains antibacterial activity for a longer period of time, ethylene oxide is added to alkyl alcohol having 16 to 20 carbon atoms. A poly (mono) ethylene glycol monoalkyl ether structure having 10 hydroxyl groups and a terminal hydroxyl group is particularly preferred.

The antibacterial agent used in the present invention is a zinc oxide-based antibacterial agent. Examples of the zinc oxide-based antibacterial agent include zinc oxide, a mixture of zinc oxide and an oxide containing at least one metal other than zinc, a eutectic or a solid solution. Specifically, ZnO, ZnO. (K ₂ O) _n , ZnO. (CaO) _n , ZnO. (Na ₂ O) _n , ZnO. (Al ₂ O ₃ ) _n , ZnO. (TiO ₂ ) _n , ZnO. (MgO) _n (n is a positive number in each formula) is preferable, and a compound represented by ZnO. (Al ₂ O ₃ ) _n (where n is a positive number) is particularly preferable. N in the formula is preferably 0.001 to 1, particularly 0.01 to 0.1. In addition, said specific compound represents a composition and does not mean that it is a eutectic.

The particle size D _50% of the antibacterial agent affects the spinnability and antibacterial effect of the nonwoven fabric. If the particle size is large, yarn breakage may occur during spinning of the nonwoven fabric. If the particle size is small, the antibacterial effect may not be sufficiently obtained. From this viewpoint, the particle size D _50% of the antibacterial agent is preferably 0.05 to 3 μ, and more preferably 0.05 to 2 μ. Here, D _50% is a value measured with laser scattered light after being dispersed with ultrasonic waves for 5 minutes or more.

  The BET specific surface area of the antibacterial agent affects the antibacterial effect and its persistence. If the BET specific surface area is small, the antibacterial effect may not be obtained, and if the BET specific surface area is large, the antibacterial effect may not be sufficiently sustained. From this viewpoint, the BET specific surface area of the antibacterial agent is preferably 1 to 300 m 2 / g, more preferably 10 to 150 m 2 / g.

  As a blending ratio of the above three components, the blending amount of the surfactant with respect to 100 parts by mass of the polyolefin is 0.1 to 5.0 parts by mass, and preferably 0.3 to 4.0 parts by mass. Moreover, the compounding quantity of the antibacterial agent with respect to 100 mass parts of polyolefins is 0.1-3.0 mass parts, Preferably it is 0.1-1.5 mass parts. When the blending ratio of the three components is within the above range, a nonwoven fabric excellent in antibacterial properties and its durability can be obtained.

  The raw material composition for forming the constituent fibers of the nonwoven fabric of the present invention may contain other components as necessary within the range not impairing the effects of the present invention in addition to the above three components.

  Other components include conventionally known heat stabilizers, weather stabilizers, various stabilizers, antioxidants, dispersants, antistatic agents, slip agents, antiblocking agents, antifogging agents, lubricants, dyes, pigments, natural And oils, synthetic oils, waxes, fillers, and the like.

  There are no particular restrictions on the method of mixing the above components. For example, a composition obtained by melt-mixing a polyolefin and a zinc-based antibacterial agent in advance and a polyolefin and a surfactant that imparts hydrophilicity are melt-mixed in advance. Each composition obtained as a masterbatch may be used as a raw material composition by mixing each masterbatch and polyolefin, or a composition obtained by melt-mixing polyolefin and a zinc-based antibacterial agent in advance may be used as a master composition. The master batch, polyolefin and a surfactant that imparts hydrophilicity may be mixed to obtain a raw material composition, or a polyolefin and a surfactant that imparts hydrophilicity may be previously melt-mixed. The resulting master batch is further mixed with a polyolefin and a zinc antibacterial agent to form a raw material composition. May be, it may be a raw material composition simply mixing the ingredients.

  The nonwoven fabric of the present invention is produced by the melt blown method or the spunbond method using the above raw material composition. The melt blown method and the spunbond method may be performed by a conventional method (for example; “Latest spinning technology”, edited by Textile Society, Kobunshi Publishing Co., Ltd., 1992, p. 117).

  If the raw material composition has the composition of the present invention, an excellent polyolefin nonwoven fabric can be easily obtained by the above method. Since the nonwoven fabric obtained in this way forms a fabric after spinning the fiber once, the exposed area of the antibacterial agent is widened and has a high antibacterial effect.

The melt flow rate (MFR) of the raw material composition (substantially polyolefin) is not particularly limited as long as the nonwoven fabric can be produced, but usually 1.5 to 1000 g / 10 min when produced by the spunbond method. , Preferably 10 to 100 g / 10 min, more preferably 30 to 80 g / 10 min. When manufactured by the melt blown method, the MFR is usually 30 g to 10000 g / 10 min, preferably 100 g to 5000 g / 10 min. More preferably, it is 200 g to 2000 g / 10 min. The MFR is measured based on the standard for each resin. For example, in the case of a propylene-based resin, the MFR is measured at 230 ° C. and a load of 2.16 kg based on ASTM D1238.
What is necessary is just to select suitably the fineness of the constituent fiber of the nonwoven fabric manufactured by the said manufacturing method, length, and the fabric weight of a nonwoven fabric according to a use.

  The nonwoven fabric of the present invention is not limited to those composed only of the raw material composition, and may be a mixed fiber of fibers made of the raw material composition and other fibers.

  The nonwoven fabric of the present invention described above has high antibacterial properties by using a raw material composition in which a nonionic surfactant that imparts hydrophilicity to polyolefin and a zinc oxide antibacterial agent are blended. In addition, it has an excellent effect that the effect is not lost even when used for a long time.

  Such a nonwoven fabric of the present invention can be used as a sanitary product, a medical product or a clothing product. Specifically, for example, disposable diapers, incontinence pads, sanitary napkins, sanitary tampons, panty sheets, sweat pads, breast pads, medical tampons, cotton swabs, emergency adhesive bandages, wet tissues, garbage collection bags, etc., surgical It can be used as a dressing, mask, gauze, bandage, bed sheet, towel, medical drape, surgeon gown, patient clothing, medical cap, medical apron, medical cover and the like.

EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further more concretely, the scope of the present invention is not limited to these Examples etc.
[Adjustment of inorganic antibacterial agent master batch A]
Zinc oxide-based antibacterial agent [manufactured by Seawater Chemical Research Co., Ltd., trade name SEABIO Z-240 (solid solution of zinc and aluminum) as an inorganic antibacterial agent 70 in 70 parts by mass of polypropylene resin (S119, manufactured by Mitsui Chemicals, Inc.) 30 parts by mass of a metallic antibacterial agent, particle size D _50% = 1μ, BET specific surface area = 20 m 2 / g), and 2 parts by mass of calcium stearate and zinc stearate as a dispersant, A master batch (inorganic antibacterial agent master batch A) having an inorganic antibacterial agent A content of 29 mass% was prepared.

[Adjustment of inorganic antibacterial agent master batch B]
Instead of inorganic antibacterial agent A, silver antibacterial agent [manufactured by Toagosei Co., Ltd., trade name: Novalon AGC303 (a metal antibacterial agent in which silver is supported on zirconium phosphate, particle size D _50%) = 1.0μ, BET specific surface area = 10 m 2 / g)], and a master batch (inorganic antibacterial agent) containing 29% by mass of inorganic antibacterial agent B in the same manner as the inorganic antibacterial agent master batch A Masterbatch B) was adjusted.

[Adjustment of surfactant masterbatch]
In the same manner as the inorganic antibacterial agent master batch A, a surfactant master batch having the following constitution was prepared.
Addition of 60% by mass of polypropylene resin (trade name: S119, manufactured by Mitsui Chemicals, Inc.), ethylene oxide (EO) of stearyl alcohol (C ₁₈ H ₃₇ OH) having poly (mono) ethylene glycol monoalkyl ether structure as a surfactant 30% by mass [C ₁₈ H ₃₇ [OC ₂ H ₄ ] _n OH (mixture of n is 1 to 10, n is an average value of 3.2)], stearyl alcohol 8% by mass, n-paraffin (C16 to C36) 2% by weight.

[Examples 1 to 3]
And by the compounding ratio (mass standard) shown in Table 1, polypropylene resin (Mitsui Chemical Co., Ltd. make, brand name: S119, MFR = 60 g / 10min.) Is used as a raw material resin, inorganic antibacterial agent master batch A and interface After dry blending the activator masterbatch, it was melted with an extruder, spun by a spunbond method, and embossed to produce a spunbond nonwoven fabric having a fineness of 2.0 denier and a basis weight of 20 g / m ² .
In addition, the compounding quantity of the polypropylene resin in a table | surface shows the compounding quantity at the time of dry blend, and does not include the polypropylene resin used for the masterbatch.
The conversion amount of inorganic antibacterial agent A, inorganic antibacterial agent B, and surfactant is the amount of inorganic antibacterial agent A, inorganic antibacterial agent B, and surfactant added to 100 parts by mass of the total polypropylene including the polypropylene used in the masterbatch. Indicates.

[Comparative Example 1]
A spunbonded nonwoven fabric was produced in the same manner as in Example 1 except that the inorganic antibacterial agent masterbatch B was used instead of the inorganic antibacterial agent masterbatch.
[Comparative Example 2]
A spunbonded nonwoven fabric was produced in the same manner as in Example 1 except that the surfactant master batch was not used.

[Test example]
About the nonwoven fabric obtained by the Example and the comparative example, the antibacterial performance before water washing and after water washing was evaluated. The antibacterial performance was evaluated by measuring the bacteriostatic activity value according to the JIS L1902 bacterial solution absorption method (antibacterial effect test method approved by the Textile Products Evaluation Technology Council). The strain used for the evaluation was Staphylococcus aureus ATCC 6538P (Staphylococcus aureus).

  Specifically, 0.4 g of a sterilized sample placed in a vial is inoculated as uniformly as possible with 0.2 mL of a bacterial solution adjusted to 1 ± 0.3 × 105 viable bacteria, and is incubated at 37 ° C. for 18 hours. Cultured. 20 mL of physiological saline supplemented with 0.2% Tween 80 was added to the culture and stirred to wash out the bacteria. A 10-fold dilution series of the washed bacteria was prepared, mixed with a nutrient agar medium, cultured at 37 ° C. for 24 hours or more, the number of colonies was counted, and the number of viable bacteria was determined.

The above test was performed for each of the standard sample and the test sample, and the bacteriostatic activity value was determined from the following formula. In addition, a cotton standard white cloth was used as a standard sample. The results are shown in Table 1.
Bacteriostatic activity value = logB-logC
B: Number of bacteria recovered after culturing the standard sample for 18 hours C: Number of bacteria recovered after culturing the test sample for 18 hours In addition, the antibacterial after washing the nonwoven with water, assuming that the nonwoven is in contact with tap water Performance was also evaluated. In the evaluation, the obtained non-woven fabric was cut into 250 mm length × 200 mm width, immersed in 2 liters of 25 ° C. tap water for 1 hour and washed with water. At this time, the chlorine ion concentration of tap water was 20 mg / L. After washing with water, the taken-out non-woven fabric was placed at room temperature, sufficiently dried, and the bacteriostatic activity value was measured by the above-mentioned bacterial liquid absorption method to evaluate the antibacterial performance. The results are shown in Table 1.
Furthermore, the bacteriostatic activity value after the water washing was subtracted from the bacteriostatic activity value before the water washing, and the bacteriostatic activity value difference before and after the water washing was calculated. The results are shown in Table 1.
The antibacterial activity value was determined to be 2.2 or more.

  As is clear from Table 1, the non-woven fabrics obtained in the examples were excellent in antibacterial properties and maintained good antibacterial properties even after washing with water.

  The nonwoven fabric of the present invention is excellent in antibacterial properties and its sustainability, and is therefore suitable as a sanitary product, medical product, clothing product and the like.

Claims (7)

  A composition obtained by mixing 0.1 to 5.0 parts by weight of a nonionic surfactant that imparts hydrophilicity to 100 parts by weight of polyolefin and 0.1 to 3.0 parts by weight of a zinc oxide antibacterial agent. Nonwoven fabric formed by the spunbond method or meltblown method.   The nonwoven fabric according to claim 1, wherein the nonionic surfactant imparting hydrophilicity has a structure composed of a polyalkylene group and a polyalkylene oxide group.   The nonionic surfactant has a poly (mono) ethylene glycol monoalkyl ether structure in which 1 to 10 ethylene oxides are added to an alkyl alcohol having 16 to 20 carbon atoms and a hydroxyl group is present at the terminal. The nonwoven fabric according to claim 1. The nonwoven fabric according to claim 1, wherein the zinc oxide-based antibacterial agent is a compound represented by the general formula; ZnO. (Al ₂ O ₃ ) _n (where n is a positive number).   A sanitary article comprising the nonwoven fabric according to claim 1.   A medical article comprising the nonwoven fabric according to claim 1.   A clothing article comprising the nonwoven fabric according to claim 1.