JP2000345434A - Conjugate binder fiber having antimicrobial property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a conjugate binder fiber suitable for nonwoven fabrics for hygienic materials and having antimicrobial property with high durability by arranging a polyester-based resin in the core part and arranging a polyolefin- based resin, to which a specific phosphite is added, having lower melting point than that of the above polyester in the sheath part. SOLUTION: This antimicrobial conjugate binder fiber is obtained by carrying out conjugate spinning so that a polyester-based resin having >=150 deg.C melting point, e.g. polyethylene terephthalate is arranged in the core part and a polyolefin-based resin such as polyethylene or polypropylene having a melting point lower by >=20 deg.C than that of the above polyester-based resin is arranged in the sheath part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite binder fiber having an antibacterial property suitable for a nonwoven fabric for a sanitizing agent.

[0002]

2. Description of the Related Art In recent years, hygiene consciousness has been increased, and it has become commonplace to provide antibacterial properties to living materials in which propagation of various bacteria is expected. Many antibacterial agents and methods for imparting antibacterial properties have been proposed. ing. For example, a method in which fine particles of a metal or a metal compound exhibiting antibacterial properties are brought into contact with an organic polymer material as a dispersion to coat and adhere to the surface of the organic polymer (Japanese Patent Laid-Open No.
Japanese Patent Application Laid-Open No. Hei 7-31028), a method of cross-linking an antibacterial agent with a melamine resin to cover the surface (JP-A-7-31028).
No. 4, JP-A-10-110388, etc.) and a method of kneading an inorganic metal-based material representing a silver zeolite (JP-A-5-272008, JP-B-63-54).
No. 013) and a method of adding a fine metal powder such as copper or zinc (Japanese Patent Application Laid-Open No. 55-130371). A quaternary ammonium salt compound (Japanese Patent Application Laid-Open No. No. 69883), a crude drug antibacterial agent as a natural compound (Japanese Patent Application Laid-Open No. 7-216731, etc.), and a method of mixing a halogen-based phenol compound (Japanese Patent Application Laid-Open No. 60-252713, etc.) have been proposed. .

However, in the method of coating and adhering to the surface of an organic polymer or in the method of cross-linking an antibacterial agent with a melamine resin to coat the surface, only the antibacterial metal is adhered to the surface. It is not preferable because the antibacterial property drops due to the dropout of the antibacterial agent in the manufacturing process. In the method of adding zeolite or metal powder having inorganic silver, copper, and zinc ions, the amount of supported zeolite is limited, and when mixed in large amounts, the physical properties of the composition are reduced, and the filter pressure of the spin pack during melt spinning is reduced. Since the temperature rises remarkably, the replacement cycle of the spin pack is shortened, and the productivity is undesirably lowered. In addition, there is a problem that coloring occurs due to elution of metal ions. A method of adding a quaternary ammonium salt-based compound or a natural compound-based herbal antibacterial agent is not preferable because thermal stability is poor. The method of mixing a halogen-based phenol compound has a problem that it cannot be used for general-purpose thermoplastic resins because halogenated phenols are contained in paraffin.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a composite binder fiber having excellent antibacterial properties even after a hydroentanglement treatment.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve the above object, and as a result, kneaded a compound having almost no antibacterial activity as an active ingredient into a polyolefin resin in a sheath. The present inventors have found that the antimicrobial property of high durability, which is the above-mentioned object, can be imparted by incorporating the antibacterial agent, and completed the present invention.

That is, the present invention relates to the first invention, wherein the melting point is 15
Polyester resin (A) at 0 ° C. or higher and 20
A composite fiber comprising a polyolefin-based resin (B) having a melting point of at least 0 ° C. and having a low melting point, wherein 0.05 to 10% by weight of at least one phosphite compound represented by the following general formula (1) is added to the polyolefin resin side. This is a composite binder fiber having antibacterial properties, wherein the polyester resin (A) forms a core portion and the polyolefin resin (B) forms a sheath portion.

[0007]

Embedded image (In the above formula, R ¹ represents a branched alkyl group having 4 to 12 carbon atoms, a cycloalkyl group or an arylalkyl group, and R ² represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group or R ³ represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an arylalkyl group or —R
⁶ COOR ⁷ represents, R ⁶ represents an alkylene group having 1 to 6 carbon atoms, R ⁷ represents an alkyl group or an aryl group having 1 to 18 carbon atoms, and R ⁴ and R ⁵ each independently represent a carbon atom. An alkyl group having 1 to 8 atoms, an alkyl group having 1 to 4 carbon atoms substituted with a hydroxy group, or a group having the following structure (2) in which R ⁴ and R ⁵ are combined. )

[0008]

Embedded image (In the above formula, R ¹ , R ² and R ³ are the same as in the case of the general formula (1).)

The second invention is the antibacterial composite binder fiber according to the first invention, wherein the phosphite compound of the general formula (1) is the following compound (α).

Embedded image

A third aspect of the present invention is the polyester binder fiber having antibacterial properties according to the first aspect, wherein the phosphite compound of the general formula (1) is the following compound (β).

Embedded image

A fourth invention is characterized in that the polyester resin (A) forming the core is polyethylene terephthalate and the polyolefin resin (B) forming the sheath is polyethylene. A composite binder fiber having antibacterial properties according to any of the above.

The fifth invention is characterized in that the polyester resin (A) forming the core is polyethylene terephthalate and the polyolefin resin (B) forming the sheath is polypropylene. A composite binder fiber having antibacterial properties according to any of the above.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The general formula (1) in the present invention
Are known compounds, and have been conventionally used as antioxidants. As a result of intensive studies, the present inventors have surprisingly found that the compound exhibits excellent antibacterial properties when melted and uniformly mixed with a thermoplastic resin. The reason why the compound exhibits antibacterial properties is not well understood, but since the compound exhibits an effect of decomposing peroxides, it is considered that this causes some inhibition in bacterial metabolism and the like.

In the general formula (1) representing the phosphite compound, the branched alkyl group having 4 to 12 carbon atoms represented by R ¹ includes, for example, secondary butyl, tertiary butyl, tertiary amyl , Tertiary octyl, isodecyl, isododecyl and the like. Examples of the alkyl group having 1 to 12 carbon atoms represented by R ² and R ³ include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, amyl, sec-amyl, tert-amyl, and octyl. , Decyl, dodecyl and the like. Examples of the arylalkyl group represented by R ¹ , R ² and R ³ include, for example,
Benzyl, cumyl and the like. Similarly, examples of the cycloalkyl group include cyclopentyl, cyclohexyl, cycloheptyl and the like.

1 to 8 carbon atoms represented by R ⁴ and R ⁵
Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, amyl, sec-amyl, tert-amyl, and octyl. Examples of the alkyl groups (1) to (4) include hydroxymethyl, hydroxyethyl, hydroxypropyl, and hydroxybutyl. Examples of the alkylene group having 1 to 6 carbon atoms represented by R ⁶ include methylene, ethylene, propylene,
Trimethylene, tetramethylene, isobutylene, pentamethylene, hexamethylene and the like. Examples of the alkyl group having 1 to 18 carbon atoms represented by R ⁷ include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, tert-pentyl, hexyl, heptyl, octyl, 3rd octyl, 2
-Ethylhexyl, nonyl, isononyl, decyl, isodecyl, undecyl, dodecyl, tridecyl, tetradecyl, hexadecyl, octadecyl and the like.

The phosphite compound in the present invention is a compound represented by the aforementioned general formula (1).
Phosphite of 2,4,6-tri-tert-butylphenol and 2-hydroxymethyl-2-ethylhexanol, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-tert. Tributyl-4
-Methylphenyl) pentaerythritol diphosphite, bis (2,4,6-tritert-butylphenyl) pentaerythritol diphosphite, bis (2,4-dicumylphenyl) pentaerythritol diphosphite,
Bis [2,6-di-tert-butyl-4- (2-butyloxycarbonylethyl) phenyl] pentaerythritol phosphite and the like, and preferably bis (2,4-di-tert-butyl) represented by compound (α) (Butylphenyl) pentaerythritol diphosphite is preferred because of its excellent compatibility with the thermoplastic resin and its excellent thermal stability.

Since the melting point of the compound is specific to the compound, the melting point of the phosphite compound contained in the present invention is not particularly limited, but the compatibility with the low melting polyester resin is improved. The temperature is preferably from 100 to 240 ° C.

When the phosphite compound of the present invention is contained in a polyolefin resin, the content is 0.05 to 10% by weight, preferably 0.1 to 5.0% by weight, based on the resin. , More preferably 0.5 to
2.0% by weight. If the content is less than 0.05% by weight, the antibacterial properties cannot be sufficiently exhibited, which is not preferable. If the content exceeds 10% by weight, the phosphite compound bleeds out, which undesirably impairs the appearance and adhesiveness of the binder fiber.

Examples of the polyolefin resin forming the sheath of the present invention include homopolymers of α-olefins such as polyethylene, polypropylene and polybutene, as well as ethylene-propylene copolymers and ethylene-methyl acrylate copolymers. It may be a copolymer. In addition, the polymerization catalyst may be any of a Ziegler-Natta-based catalyst and a metallocene-based catalyst. From the viewpoints of versatility and workability, polyethylene or polypropylene is preferred.

Examples of the polyester resin forming the core of the composite binder fiber of the present invention include terephthalic acid, isophthalic acid, naphthalene 2,6-dicarboxylic acid, naphthalene 2,7 dicarboxylic acid, diphenyl 4-4 'dicarboxylic acid and the like. Aromatic carboxylic acids, alicyclic carboxylic acids such as 1,4 cyclohexanedicarboxylic acid, succinic acid, adipic acid,
At least one dicarboxylic acid selected from aliphatic dicarboxylic acids such as sebacic acid and dimer acid or ester-forming derivatives thereof, and ethylene glycol, trimethylene glycol, 1,4-butanediol, tetramethylene glycol, pentane Aliphatic diols such as methylene glycol and hexamethylene glycol, 1,1-
It is a block copolymer composed of at least one diol component selected from alicyclic diols such as cyclohexanedimethanol and 1,4-cyclohexanedimethanol, and ester-forming derivatives thereof. Further, polyester polyether block copolymers obtained by copolymerizing at least one of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polyalkylene diol comprising an ethylene oxide-propylene oxide copolymer having an average molecular weight of 300 to 5,000 are added to these systems. Polymers may be used, and the average molecular weight is 30.
A polyester ester block copolymer obtained by copolymerizing at least one of polyester diols such as polylactones of 0 to 5000 may be used, but polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate are preferable from the viewpoint of yarn-forming properties.

Although the production method of the present invention is not particularly limited, (a) a predetermined amount of a phosphite compound is mixed with a polyolefin resin, melt-kneaded and re-pelletized, and then mixed with a usual core-sheath composite. Using a fiber manufacturing device, a method of forming a composite fiber with a polyester resin as a core melted by another extruder, (b) melt-kneading after mixing a high-concentration phosphite compound with a polyolefin resin. (C) mixing the pellets re-pelletized into master pellets, mixing the resulting pellets with polyolefin-based resin pellets in a predetermined amount during fiber formation, and forming a composite fiber in the same manner as in (a). A method in which a predetermined amount of a phosphite compound is metered into a polyolefin-based resin, charged into an extruder, melt-mixed, and formed into a composite fiber in the same manner as in (a) and (b). Etc. there is.

In the method (a), a known amount of a phosphite compound is added to a polyolesin resin and a predetermined amount (0.01 to 10% by weight) using a known blender such as a tumbler type mixer. I do. It is preferable that the phosphite compound is vacuum-dried at room temperature to reduce the water content to 0.02% by weight or less, and is added and mixed with the polyolefin resin under a nitrogen purge. When the mixing time is about 5 to 30 minutes, blending is performed almost uniformly. Next, it is taken out into a container and supplied from the container to an extruder to be melt-kneaded. The extruder uses a single screw or a twin or triple screw. The screw shape of the extruder is preferably a known kneading screw, more preferably kneading with a twin screw extruder. In such a pelletizing step, there is a concern that foreign matter may be mixed, but a filter is preferably used in order to remove the foreign matter. Although the specifications of the filter differ depending on the target product, 20 to 12
00 mesh is used by lamination, or a metal sintered filter is used in combination. The diameter of the orifice of the die at the exit of the extruder is determined by the extrusion amount of the extruder, but usually, a die having a diameter of 1 to 3 mm is used. Since a general kneading extruder does not have a measuring and feeding device, the extruding amount is set to a condition for obtaining pellets of a desired size from the amount of extruding pressure, the number of rotations of a screw and the take-up speed of a strand cutter. After the strand extruded from the die is cooled, the strand is cut into a desired length by a strand cutter to obtain a pellet. The obtained pellets are melted by an extruder, combined with a polyester resin melted and discharged from another extruder in a spin pack, and discharged from a nozzle having a plurality of orifices. The weight ratio of the composite fiber is controlled by the discharge amount of the metering pump. The composite fiber discharged from the nozzle orifice is cooled immediately below the nozzle and, after being provided with a fiber treatment agent, once wound up,
It is shaken off in a tow can. Next, bundle the undrawn yarn, draw,
If it is cut to a desired length after heat treatment and crimping, it becomes crimp short fibers, and if it is cut to a desired length without crimping, it becomes non-crimped short fibers.

In the method (b), the addition amount of the phosphite compound in the master batch pellets is adjusted so that the addition amount of the phosphite compound in the polyolefin resin at the time of forming the fiber becomes a desired amount. Is added and mixed in the same manner as in the method (a) and melt-kneaded to prepare a master pellet. The concentration of the phosphite compound in the master pellet is determined by the mixing ratio in the next spinning step. Usually, 5 to 50% by weight of master pellets and a thermoplastic resin for dilution are mixed and used. The feeding method to the spinning machine is such that a predetermined amount of the master pellet and the thermoplastic resin for dilution are kneaded and supplied in a predetermined amount to an extruder, and fiberized in the same manner as (a).

The method (c) includes a method in which a predetermined amount of a phosphite compound and a polyolefin resin are once mixed, then supplied to an extruder, melt-kneaded, and then extruded from a nozzle orifice. There is a method in which the acid ester compound and the polyolefin-based resin are separately supplied to an extruder in a fixed amount, directly mixed and melt-kneaded, and then fiberized by the same method as (a). In the method (c), the screw of the extruder of the spinning machine is preferably of a kneading type, and a spinning machine incorporating a kneading mechanism (for example, a static mixer) in addition to the screw of the extruder is preferable.

The center of gravity of the core and the sheath of the present invention may be concentric or eccentric. However, it is not preferable that the core is too eccentric and the core is exposed on the fiber surface.

As a preferred embodiment of the present invention, a hollow core-sheath type composite fiber having a hollow portion in the core portion or an irregular cross section such as a three-leaf or five-leaf cross section can be selected. In order to form a hollow cross section, an orifice having a nozzle orifice shape in which a circular slit is connected by one bridge or three bridges is used. Nozzle orifice hollow ratio is 40-70%
Can be selected. When the hollow ratio of the nozzle orifice is less than 40%, the hollow ratio of the yarn cross section is less than 10%, and it is difficult to obtain a hollowing effect. When the hollow ratio is more than 70%, the hollow ratio of the fiber cross section is too high. This is not preferred because the probability of hollow rupture occurring in the post-processing step increases. A preferable nozzle hollow ratio is 45 to 65%. The hollow ratio of the fiber cross section is preferably 10 to 40%. As a method of deforming the fiber cross section, a method of deforming the nozzle orifice is generally used. The irregular cross section can be selected according to a desired use such as a Y shape, a cross shape, and a star shape.

In a preferred embodiment of the present invention, the ratio of the core component to the sheath component can be 30:70 to 70:30. Preferably, from 40:60 to 60:40. More preferably, the ratio is 50:50. If the core component ratio is less than 30, the antibacterial properties are sufficient, but the mechanical properties of the fiber structure are poor, which is not preferable. On the other hand, when the sheath component ratio is less than 30, the antibacterial property is sufficient, but the adhesiveness is insufficient,
Not preferred.

In a preferred embodiment of the present invention, the single yarn fineness is in the range of 0.5 to 30 dtex and the fiber length is 5
mm to 100 mm. If the fineness is less than 0.5 dtex, it is not preferable because the spinning property is difficult and the productivity is low. If the fineness exceeds 30 dtex, the texture of the obtained nonwoven fabric becomes too hard, which is not preferable. Also,
If the fiber length is less than 5 mm, when a nonwoven fabric structure is formed, sufficient inter-fiber entanglement cannot be obtained, and only a low strength nonwoven fabric can be obtained, which is not preferable. Fiber length is 100
If it exceeds mm, there is a problem in card passing property, which is not preferable.

[0029]

The present invention will be described in detail with reference to the following examples. Examples 1 to 11 and Comparative Examples 1 to 4 Evaluations in the examples were performed by the following methods. (1) Evaluation of antibacterial activity This was based on the Manual for Quantitative Antibacterial Testing Method for Textile Products, which was established by the Evaluation Committee for New Functions of Textile Products. That is, 0.4 g of a sample of the following test bacteria (1 ± 0.3 × 10 ⁵ cells / ml) is uniformly inoculated into a sterilized 1/20 concentration nutrient broth and cultured at 37 ° C. for 18 hours. After completion of the culture, the test bacteria were washed out, and a pour plate agar medium was prepared using the solution.
The cells are cultured at 7 ° C for 24-48 hours, and the number of viable cells is measured. In addition,
As for the unprocessed product, the test bacteria are washed out immediately after inoculation, and the solution is used to prepare a pour plate agar medium at 37 ° C. for 24 to 48 hours.
After culturing for a period of time, the number of inoculated viable bacteria is measured. The antibacterial activity is evaluated by a bacteriostatic activity value according to the following formula. The higher the bacteriostatic activity value, the better the antibacterial property. If the bacteriostatic activity value ≥ 2.2, it can be said that the bacteriostatic property is antibacterial. In addition, Staphylococcus (Staphylococcus) was used as a test bacterium.
us Aureus ATCC 6538P) was used. Bacteriostatic activity value = Log (B)-Log (C) However, test establishment conditions: Log (B)-Log (A)>
1.5 must be satisfied. A: Average value of the number of bacteria collected immediately after inoculation of the raw product B: Average value of the number of bacteria collected and cultured for 18 hours of the raw product C: Average value of the number of bacteria collected and cultured for 18 hours of the processed product

Production Example A polyolefin resin to which a phosphite compound has been added is melt-extruded by an extruder, and a polyester resin is melt-extruded by another extruder. Then, each is measured by a gear pump and extruded into a spinning pack. After the composite is formed, the liquid is discharged from a nozzle having a plurality of orifices. The discharged multifilament is gradually cooled and then wound up. The wound undrawn yarn is bundled into tens of thousands of deniers, stretched so that the single yarn fineness becomes 2 dtex, and then crimped with a push-in type crimping device.
By cutting into a fiber length of 1 mm, a core-sheath composite short fiber was obtained. In addition, composite binder fibers were prepared using the combinations shown in Table 1 and the added amounts of the phosphite compounds. As the phosphite compound, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite (hereinafter abbreviated as BMPP) or bis (2
6-di-tert-butylphenyl) pentaerythritol diphosphite (hereinafter abbreviated as BHPP) was added.

A sample for evaluation of antibacterial activity was prepared as follows. After the obtained composite binder fiber is made into a web with a card, the fibers are entangled with each other by a needle punch, and the polyolefin resin is melted in an oven and treated at a temperature sufficient for point bonding, so that a needle-punched nonwoven fabric is formed. Obtained. In addition, as a sample for evaluating the anti-water entanglement property of the antibacterial property, a web is formed with a card in the same manner as the above sample, and the fibers are entangled by a water entanglement treatment (water punch), and the polyolefin resin is placed in an oven. Was melted and treated at a temperature sufficient for spot joining to obtain a water-punched nonwoven fabric. Table 1 shows the evaluation results.

[0032]

[Table 1] ○: good △: good ×: bad

According to Examples 1 to 9, it is understood that the composition has high antibacterial properties even after the water punch treatment. On the other hand, when the addition amount of the phosphite compound is out of the range of the present invention as in Comparative Example 1, after the water punch treatment, the level is lower than the level that can be said to be antibacterial. According to Examples 10 and 11,
By making the fiber cross section hollow, it is possible to impart a bulky and lightweight feeling to the raw cotton and the nonwoven fabric. On the other hand, Comparative Example 3
When the hollow ratio is excessively increased as in the above, hollow crushing occurs in the raw cotton production process and the nonwoven fabric production process, and the bulkiness of the nonwoven fabric is reduced.

[0034]

According to the present invention, a phosphite compound which is conventionally used as an agent for preventing heat deterioration and discoloration and has almost no antibacterial properties by itself is melted in a polyolefin resin as a sheath component of a core-sheath type composite fiber. By mixing and kneading, a composite binder fiber having sufficient antibacterial properties even after processing can be provided.

Continuing from the front page (72) Inventor Kenji Yoshino 2-1-1 Katata, Otsu-shi, Shiga F-Term in Toyobo Co., Ltd. Research Laboratory 4H011 AA02 BA01 BB17 BC19 DA10 DF03 DH02 DH04 4L041 AA07 BA02 BA05 BA21 BA42 BA49 BA59 BC10 BD03 BD07 BD11 CA06 CA07 CA36 CA38 CB19 CB28 DD01 DD05 DD14 DD21

Claims (5)

[Claims] 1. A conjugate fiber comprising a polyester resin (A) having a melting point of 150 ° C. or higher and a polyolefin resin (B) having a melting point of 20 ° C. or lower and having a general formula (1) on the polyolefin resin side: Wherein at least one phosphite compound represented by the formula (1) is added in an amount of 0.05 to 10% by weight, the polyester resin (A) forms a core portion, and the polyolefin resin (B) forms a sheath portion. Composite binder fiber with antibacterial properties. Embedded image (In the above formula, R ¹ represents a branched alkyl group having 4 to 12 carbon atoms, a cycloalkyl group or an arylalkyl group, and R ² represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group or R ³ represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an arylalkyl group or —R
⁶ COOR ⁷ represents, R ⁶ represents an alkylene group having 1 to 6 carbon atoms, R ⁷ represents an alkyl group or an aryl group having 1 to 18 carbon atoms, and R ⁴ and R ⁵ each independently represent a carbon atom. An alkyl group having 1 to 8 atoms, an alkyl group having 1 to 4 carbon atoms substituted with a hydroxy group, or a group having the following structure (2) in which R ⁴ and R ⁵ are combined. ) (In the above formula, R ¹ , R ² and R ³ are the same as in the case of the general formula (1).) 2. The antibacterial composite fiber according to claim 1, wherein the phosphite compound of the general formula (1) is the following compound (α). Embedded image 3. The antibacterial composite binder fiber according to claim 1, wherein the phosphite compound of the general formula (1) is the following compound (β). Embedded image 4. A polyester resin for forming a core (A)
Is polyethylene terephthalate, and the polyolefin-based resin (B) forming the sheath is polyethylene. The composite fiber having antibacterial properties according to any one of claims 1 to 3, wherein 5. A polyester resin (A) forming a core portion.
Is polyethylene terephthalate, and the polyolefin resin (B) forming the sheath is polypropylene. The composite binder fiber having antibacterial properties according to any one of claims 1 to 3, wherein