JP2007023398A - Polypropylene resin composition for filament nonwoven fabric - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polypropylene composition for filament nonwoven fabric capable of providing a nonwoven fabric having good mechanical properties and formation and a spunbonded nonwoven fabric using the composition. <P>SOLUTION: The polypropylene resin composition for filament nonwoven fabrics comprises 100 pts.wt. polypropylene resin and 0.005-0.15 pt.wt. hydrotalcites, and in the resin composition, polydispersity index (PI) is within the range of 2.5 to 4.5 and the melt flow rate is within the range of 20 to 150 g/10 min. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polypropylene resin composition for long-fiber nonwoven fabrics, and particularly relates to a polypropylene resin composition from which a long-fiber nonwoven fabric with good texture can be obtained.

  Long fiber nonwoven fabrics such as spunbond nonwoven fabrics are obtained by accumulating long fiber groups obtained by melt spinning on a collection conveyor to obtain a fiber web, and then bonding the long fibers together by any means. It is what Therefore, since the long fibers, which can be said to be continuous fibers, are used as the constituent fibers, the mechanical properties such as tensile strength are excellent as compared with the short fiber nonwoven fabric using the short fibers as the constituent fibers. In addition, since the non-woven fabric can be obtained by opening and accumulating the long fibers obtained by melt spinning as compared with the non-woven fabric obtained by opening and accumulating the obtained fibers by the card method or the wet method, it is more efficient. There is an advantage that can be produced.

It is known that polypropylene is used as a material for such a long fiber nonwoven fabric, and it is known that a polypropylene having a high melt flow rate and a narrow molecular weight distribution is suitable for these nonwoven fabric polypropylenes.
However, if the molecular weight distribution is too narrow, the fiber group greatly shakes during spinning, and the texture of the nonwoven fabric deteriorates. If the texture of the nonwoven fabric deteriorates, there will be places where the strength and elongation of the nonwoven fabric are significantly reduced, so when processing into final products such as paper diapers and masks, troubles due to breakage of the nonwoven fabric occur, and the advantages of the spunbond method You can not enjoy it. In recent years, the nonwoven fabric processing speed has been increased, but the nonwoven fabric has a tendency to deteriorate along with it. Therefore, there is an increasing demand for a nonwoven fabric having a stable texture even in high-speed processing.

In addition, when producing nonwoven fabrics by the spunbond method, there is also a problem that smoke is generated from the vicinity of the spinning nozzle. As a countermeasure, a specific amount of hydrotalcite is required for a polypropylene resin having a specific melt flow rate value. A method of blending a kind is disclosed (for example, see Patent Document 1). However, simply adding hydrotalcite to general polypropylene resin has the effect of suppressing smoke generation, but it is not possible to improve the mechanical properties and texture of the resulting nonwoven fabric. Met.
Japanese Patent Laid-Open No. 10-265627

  In view of the above problems, an object of the present invention is to provide a polypropylene resin composition for a long-fiber nonwoven fabric from which a nonwoven fabric with good mechanical properties and texture can be obtained.

  As a result of intensive studies to solve the above problems, the present inventors have added a specific amount of hydrotalcite to a polypropylene resin and adjusted it to have a specific melt flow rate and PI (polydispersity index). It was found that when the polypropylene resin composition was used for forming a long-fiber nonwoven fabric, the mechanical properties and texture of the nonwoven fabric were improved, and the present invention was completed.

  That is, according to the first aspect of the present invention, a polydispersity index (PI) containing 0.005 to 0.15 parts by weight of hydrotalcites with respect to 100 parts by weight of a polypropylene resin is 2 (polydispersity index). There is provided a polypropylene resin composition for a long-fiber nonwoven fabric having a melt flow rate in the range of 20 to 150 g / 10 min.

  According to the second invention of the present invention, there is provided a spunbonded nonwoven fabric formed by using the polypropylene resin composition for long-fiber nonwoven fabric of the first invention.

  The polypropylene resin composition for long-fiber nonwoven fabric of the present invention can produce a nonwoven fabric with good mechanical strength and texture since MFR and PI are adjusted and hydrotalcite is added in an appropriate amount.

  The present invention is a resin composition in which a hydrotalcite is blended with a polypropylene resin, and the resin composition has a PI (Polydispersity Index) of 2.5 to 4.5 and an MFR of 20 It is the polypropylene resin composition for long-fiber nonwoven fabrics which is -150g / min. Below, the structural component of the resin composition of this invention, the characteristic of a resin composition, and the nonwoven fabric obtained from a resin composition are demonstrated in detail.

1. Component of Polypropylene Resin Composition (1) Polypropylene resin The polypropylene resin used in the polypropylene resin composition for long-fiber nonwoven fabric of the present invention is a propylene homopolymer, propylene and ethylene and / or an α-olefin having 4 to 20 carbon atoms. And a crystalline random copolymer or a crystalline block copolymer.
Specific α-olefins used as comonomers include ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 4-methyl-pentene-1, 4-methyl-hexene-1. 4,4-dimethylpentene-1 and the like, and one or a combination of two or more may be used.
These polypropylene resins can be used alone or in combination of two or more. A small amount of other olefin resin such as polyethylene can also be blended.

The melt flow rate (MFR) of the polypropylene resin used in the present invention is preferably 1 to 30 g / min, more preferably 5 to 20 g / min. Within this range, the melt flow rate of the polypropylene resin composition for long-fiber nonwoven fabric can be easily adjusted to a range of 20 to 150 g / 10 min.
Here, MFR is a value measured at 230 ° C. and a load of 21.1 N according to the JIS-K6921-2 appendix.

The PI (polydispersity index) of the polypropylene resin used in the present invention is preferably 2.5 to 10, more preferably 2.5 to 6. Within this range, the PI of the polypropylene resin composition for long-fiber nonwoven fabric can be easily adjusted to a range of 2.5 to 4.5.
Here, the PI is a storage elastic modulus (G ′) [Pa], a loss elastic modulus (A) of a strain of 10%, a shear rate of 0.3 to 300 rad / sec, and a temperature of 170 ° C. using an ARES of Rheometrics. G ″) [Pa] is measured, an intersection (Gc) of the measured G ′ and G ″ is obtained, and the value is substituted into the following equation (I) and calculated.
Dispersion index (PI) = 10 ⁵ / Gc (I)

  The polypropylene resin used in the present invention can be obtained by polymerizing propylene using a highly stereoregular polymerization catalyst. As the highly stereoregular polymerization catalyst, a so-called Ziegler-Natta catalyst using a titanium compound prepared using titanium chloride, alkoxy titanium, or the like as a starting material, or a Kaminsky catalyst using a metallocene compound may be used. However, since the PI of the polypropylene resin can be easily adjusted to a range of 2.5 to 4.5, a Kaminsky catalyst is desirable.

As the polymerization mode of propylene using the catalyst as described above, any method can be adopted as long as the catalyst component and the monomer come into efficient contact. Specifically, the slurry method using an inert solvent, the bulk method using propylene as a solvent substantially without using an inert solvent, the solution polymerization method, or the monomers are substantially gaseous without using a liquid solvent substantially. It is possible to employ a gas phase method that keeps the temperature constant.
It is also applied to continuous polymerization and batch polymerization. In the case of slurry polymerization, a saturated aliphatic or aromatic hydrocarbon such as hexane, heptane, pentane, cyclohexane, benzene and toluene can be used alone or as a polymerization solvent.
In these polymerization methods, the MFR of polypropylene is adjusted by introducing hydrogen. In this case, the amount of hydrogen introduced may be constant from the start to the end of the polymerization or may be changed continuously or stepwise. .
In addition, such a polypropylene resin can be selected and obtained from commercially available products.

(2) Hydrotalcite Hydrotalcite used in the polypropylene resin composition for long-fiber nonwoven fabric of the present invention is generally Mg ₆ Al ₂ (OH) ₁₆ .CO ₃ .4H ₂ O [trade name: DHT- 4A (manufactured by Kyowa Chemical Co., Ltd.), Mg ₃ ZnAl ₂ (OH) ₁₂ CO ₃ · mH ₂ O [trade name: ZHT-4A (manufactured by Kyowa Chemical Co., Ltd.), Mg ₆ Al ₂ (OH) ₁₂ · CO described by the chemical formula ₃ · 3H 2 _O or the like as a complex inorganic compounds.

  When hydrotalcite is added to polypropylene resin, the fibers tend to repel each other during the opening process when the nonwoven fabric is formed, so that the nonwoven fabric feels good and the nonwoven fabric has good mechanical strength. Will be able to.

  Content of the hydrotalcite in the polypropylene resin composition for long fiber nonwoven fabrics of the present invention is 0.005 to 0.15 parts by weight, preferably 0.02 to 0.06 parts per 100 parts by weight of the polypropylene resin. Parts by weight. Resins having a hydrotalcite content of less than 0.005 parts by weight have no effect of adding hydrotalcite, so the texture of the nonwoven fabric is not improved. On the other hand, when the content of hydrotalcite exceeds 0.15 parts by weight, the hydrotalcite becomes poorly dispersed, and many yarn breaks occur during spinning, making it impossible to form a nonwoven fabric.

(3) Other components In the polypropylene resin composition for long-fiber nonwoven fabric of the present invention, various additives such as heat stabilizers, antioxidants, peroxides, Waxing agent, lubricant, light stabilizer, weathering stabilizer, ultraviolet absorber, crystal nucleating agent, copper damage inhibitor, antistatic agent, slip agent, anti-blocking agent, antifogging agent, colorant, filler, elastomer, Petroleum resin, hydrophilizing agent and the like can be blended. In particular, peroxides are effective for adjusting the PI and MFR of the polypropylene resin composition.

2. Properties of polypropylene resin composition for long-fiber nonwoven fabric The polypropylene resin composition for long-fiber nonwoven fabric of the present invention is prepared by heating the above components at 180 to 300 ° C. using a known method, for example, a dry blend state or a melt kneader. It is obtained by a melt kneading technique.
The MFR of the polypropylene resin composition for a long-fiber nonwoven fabric of the present invention is required to be 20 to 150 g / 10 minutes, and preferably 30 to 70 g / 10 minutes. When the MFR is less than 20 g / 10 min, the yarn breakage occurs frequently just below the spinning nozzle when forming the nonwoven fabric, making it impossible to form the nonwoven fabric. On the contrary, when MFR exceeds 150 g / 10 minutes, since the fiber group is greatly shaken between the spinning nozzle and the air soccer, the fibers are bonded to each other, so the texture of the nonwoven fabric is deteriorated. Adjustment of MFR in the resin composition is performed by adding a peroxide to the raw material powder during pellet granulation.
Here, MFR is a value measured by the same method as for polypropylene resin.

Moreover, PI of the polypropylene resin composition for long fiber nonwoven fabrics of this invention needs to be 2.5-4.5, Preferably it is 2.7-4.0, More preferably, it is 2.7. ~ 3.3. If the PI is less than 2.5, the nonwoven fabric is deteriorated because the fibers adhere to each other when the nonwoven fabric is formed by largely shaking the fiber group between the spinning nozzle and the air soccer. On the contrary, when PI exceeds 4.5, the yarn breakage in high-speed spinning becomes remarkable, and the texture of the nonwoven fabric deteriorates. In the polypropylene resin composition, PI is an index representing the molecular weight distribution, and the PI in the resin composition is adjusted by a method of adding a peroxide to the raw material powder during pellet granulation.
Here, PI is a value measured by the same method as for polypropylene resin.

3. Molding of non-woven fabric The polypropylene resin composition for long-fiber non-woven fabric of the present invention is suitably used for molding spunbonded non-woven fabric. Spunbond nonwoven fabric molding is a process in which a polypropylene resin composition is put into an extruder, melt-spun using a spinneret, and a fiber group discharged from the spinneret is introduced into an air soccer ball and pulled to obtain a long fiber group. Subsequently, the long fiber group discharged from the air soccer is deposited as a long fiber fleece on a collecting endless net conveyor provided with a suction device on the back surface.

  The fineness of the long fibers constituting the spunbonded nonwoven fabric thus obtained is preferably 0.5 to 20 dtex / f. If the fineness of the long fibers is less than 0.5 dtex / f, the spinnability is lowered by high-speed spinning for maintaining the productivity, and the productivity is lowered for maintaining the spinnability. On the other hand, if the fineness of the long fibers exceeds 20 dtex / f, the rigidity of the long fibers is increased, and a spunbond nonwoven fabric rich in flexibility cannot be obtained. When the obtained spunbonded nonwoven fabric is used as a surface material for absorbent articles, it is particularly preferable that the fine fibers have a fineness of 0.5 to 6 dtex / f.

In addition, the basis weight of the spunbonded nonwoven fabric can be arbitrarily selected depending on the application to be used, but when used for surgical clothes, cloths, base materials for hap materials, etc., those having a range of 5 to 200 g / m ² are available. preferable. When the weight is less than 5 g / m ² , the basis weight is too small, the thickness of the spunbond nonwoven is too thin, and when fixing the long fiber fleece or when winding the fixed spunbond nonwoven, Problems such as difficulty in handling and reduced homogeneity are likely to occur. On the other hand, when it exceeds 200 g / m ² , the basis weight is too large, the rigidity of the spunbonded nonwoven fabric itself is increased, and the flexibility is easily lowered. In the case of using the surface material or the like of the absorbent article, the basis weight of the spunbonded nonwoven fabric is in the range of 5 to 50 g / m ² is particularly preferred.

The long fibers constituting the present invention may be single-component long fibers or composite long fibers composed of two or more components.
A composite long fiber is generally a composite fiber composed of a high melting point resin component and a low melting point resin component or a low softening point resin component, where the low melting point resin component or the low softening point resin component is a surface along the longitudinal direction of the fiber. It has a structure of two or more components exposed to at least a part of. The polypropylene resin composition for long-fiber nonwoven fabric of the present invention is desirably used as a low melting point resin component or a low softening point resin component.
The melting point difference or softening point difference between the high melting point component and the low melting point component or the low softening point component constituting the composite long fiber is preferably 15 ° C. or higher.
The melting point or softening point of these resin components can be measured as the temperature at the apex of the endothermic peak of the endothermic peak curve by DSC (indicative scanning calorimetry) with a heating rate of 10 ° C./min. The measurement of the softening point is based on JIS-K7206 “Testing method for Vicat softening temperature of thermoplastics”.
In addition, as the composite long fiber, a sheath core type, an eccentric sheath core type, a parallel type, a multilayer type, a sea island type, and a radiation type structure can be used. In particular, composite core fibers of a sheath core type and an eccentric sheath core type are preferable because they have good heat-fusibility. Depending on the application, the long fiber may be added with a colorant, a light-resistant agent, a flame retardant, an antibacterial agent, and the like. Furthermore, the cross-sectional shape of the long fibers may be circular or irregular (non-circular), and the long fibers having these cross-sectional shapes may be hollow.

  The spunbond nonwoven fabric can be suitably used not only as a single layer, but also as a laminate of a spunbond nonwoven fabric and a meltblown nonwoven fabric, or a laminate of a film or water absorbent paper.

Since the nonwoven fabric obtained by the present invention uses a polypropylene resin composition having the above properties, it has excellent mechanical properties and texture.
Here, the nonwoven fabric excellent in texture means one having a standard deviation of 2 or less in the measurement of strength and elongation, and the nonwoven fabric excellent in texture is preferably used in the field of diaper backsheets because of its good appearance. It is done.

  EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to the following Example, unless the summary is exceeded. The physical properties are measured as follows. Moreover, the manufacturing method of the propylene polymer used by the Example and the comparative example was shown to the polymerization example.

(1) MFR: Measured according to JIS-K6921-2 appendix. (Conditions: Temperature / 230 ° C, Load 21.18N)
(2) PI: Storage elastic modulus (G ′) [Pa], loss elastic modulus (G) under conditions of strain 10%, shear rate 0.3 to 300 rad / sec, 170 ° C. using AHE of Rheometrics. ") [Pa] is measured. An intersection (Gc) of the measured G 'and G" is obtained, and the value is substituted into the following formula (I).
Dispersion index (PI) = 10 ⁵ / Gc (I)
(3) Tensile strength and elongation of nonwoven fabric: Measured under the following conditions in accordance with JIS-L1096.
Measuring device: RTC-1210A manufactured by Orientec Co., Ltd.
Test piece: 50 mm × 100 mm One direction in the machine direction (MD) Test condition: Chuck distance: 50 mm, Tensile speed: 50 mm / min (4) Nonwoven fabric texture: Measure the strength and elongation of the nonwoven fabric 10 times per sample The standard deviation of the measured value is obtained. When the standard deviation was 2 or less, the texture of the nonwoven fabric was good. A sample with a good texture of the nonwoven fabric has a small standard deviation because the strength and elongation cannot be changed. On the other hand, a sample with poor texture of the nonwoven fabric has a large standard deviation because the strength and elongation vary.

(Polymerization example 1)
(1) Preparation of catalyst In a 1 liter reaction vessel equipped with a reflux condenser, 8.3 g of chip-shaped metal magnesium (purity 99.5%, average particle size 1.6 mm) and n-hexane were added in a nitrogen gas atmosphere. After adding 250 ml and stirring at 68 ° C. for 1 hour, magnesium metal was taken out and dried at 65 ° C. under reduced pressure to obtain preactivated metal magnesium. Next, a suspension obtained by adding 140 ml of n-butyl ether and 0.5 ml of n-butyl ether chloride solution (1.75 mol / liter) to this metal magnesium was kept at 55 ° C., and further, n-butyl ether. A solution prepared by dissolving 38.5 ml of n-butyl chloride in 50 ml was added dropwise over 50 minutes. After reacting for 4 hours at 70 ° C. with stirring, the reaction solution was kept at 25 ° C.
Subsequently, 55.7 ml of HC (OC ₂ H ₅ ) _{3 was} added dropwise to the reaction solution over 1 hour. After completion of the dropwise addition, the reaction was carried out at 60 ° C. for 15 minutes, the reaction product solid was washed 6 times with 300 ml each of n-hexane, dried under reduced pressure at room temperature for 1 hour, 19.0% magnesium and 28.9% chlorine. 31.6 g of a magnesium-containing solid was collected. In a 300 ml reaction vessel equipped with a reflux condenser, a stirrer, and a dropping funnel, 6.3 g of a magnesium-containing solid and 50 ml of n-heptane were placed in a nitrogen gas atmosphere to form a suspension, and 2,2,2- A mixed solution of 20 ml (0.02 mmol) of trichloroethanol and 11 ml of n-heptane was dropped from the dropping funnel over 30 minutes and further stirred at 80 ° C. for 1 hour. The obtained solid was separated by filtration, washed 4 times with 100 ml each of n-hexane at room temperature, and further washed twice with 100 ml each of toluene to obtain a solid component.
40 ml of toluene was added to the above solid component, and further titanium tetrachloride was added so that the volume ratio of titanium tetrachloride / toluene was 3/2, and the temperature was raised to 90 ° C. Under stirring, a mixed solution of 2 ml of di-n-butyl phthalate and 5 ml of toluene was added dropwise over 5 minutes, followed by stirring at 120 ° C. for 2 hours. The obtained solid substance was filtered off at 90 ° C. and washed twice with 100 ml of toluene at 90 ° C. Further, titanium tetrachloride was newly added so that the volume ratio of titanium tetrachloride / toluene was 3/2, stirred at 120 ° C. for 2 hours, washed with 100 ml of n-hexane at room temperature 7 times, and component A5 .5 g was obtained.

(2) Prepolymerization Into a 500 ml reactor thoroughly purged with nitrogen, 4.0 g of the component A obtained above and 200 ml of n-hexane were placed in a nitrogen gas atmosphere, and cooled to −5 ° C. with stirring. did. Next, 20 mmol and 2 mmol of triethylaluminum and t-butoxycyclopentyldimethoxysilane were added, respectively, and stirred for 5 minutes. Next, after reducing the pressure in the system, propylene gas was continuously supplied, and propylene was polymerized at 0 ° C. for 1 hour. After completion of the polymerization, the solid component was washed with 200 ml of n-hexane three times at room temperature. Furthermore, the solid component was dried under reduced pressure at room temperature for 1 hour to obtain 16.2 g of a catalyst component. The amount of prepolymerization was 3.05 g per 1 g of component A.

(3) Production of Propylene Polymer A hexane diluted solution of liquefied propylene, hydrogen, cyclohexylmethyldimethoxysilane and triethylaluminum was continuously supplied to a reactor having an internal volume of 400 L, and the internal temperature was maintained at 70 ° C. The supply amounts of propylene, cyclohexylmethyldimethoxysilane, and triethylaluminum were 167 kg / H, 0.005 kg / H, and 0.015 kg / H, respectively. Hydrogen was supplied so that the hydrogen concentration in the gas phase was 0.53 mol%. The prepolymerized catalyst was slurried with liquid paraffin and fed with solid component A at 5.7 g / H. As a result of operating so that the average residence time of the reaction was 1.0 H, propylene polymer I was obtained at a production rate of 84 kg / H. The MFR of this homopolymer was measured and found to be 1.6 g / 10 minutes.

(Polymerization example 2)
A hexane diluted solution of liquefied propylene, hydrogen, cyclohexylmethyldimethoxysilane and triethylaluminum was continuously supplied to a reactor having an internal volume of 400 L, and the internal temperature was maintained at 70 ° C. The supply amounts of propylene, cyclohexylmethyldimethoxysilane, and triethylaluminum were 166 kg / H, 0.005 kg / H, and 0.015 kg / H, respectively. Hydrogen was supplied so that the hydrogen concentration in the gas phase was 2.58 mol%. The prepolymerized catalyst used in Polymerization Example 1 was slurried with liquid paraffin and fed with solid component A at 4.8 g / H. As a result of operating so that the average residence time of the reaction was 1.0H, propylene polymer II was obtained at a production rate of 87 kg / H. The MFR of this homopolymer was measured and found to be 10.5 g / 10 minutes.

(Polymerization Example 3)
A hexane diluted solution of liquefied propylene, hydrogen, cyclohexylmethyldimethoxysilane and triethylaluminum was continuously supplied to a reactor having an internal volume of 400 L, and the internal temperature was maintained at 70 ° C. The supply amounts of propylene, cyclohexylmethyldimethoxysilane, and triethylaluminum were 175 kg / H, 0.005 kg / H, and 0.015 kg / H, respectively. Hydrogen was supplied so that the hydrogen concentration in the gas phase was 3.4 mol%. The prepolymerized catalyst used in Polymerization Example 1 was slurried with liquid paraffin and fed with solid component A at 3.3 g / H. As a result of operating so that the average residence time of the reaction was 1.0H, propylene polymer III was obtained at a production rate of 87 kg / H. It was 16.0 g / 10min when MFR of this homopolymer was measured.

(Polymerization example 4)
A hexane diluted solution of liquefied propylene, hydrogen, cyclohexylmethyldimethoxysilane and triethylaluminum was continuously supplied to a reactor having an internal volume of 400 L, and the internal temperature was maintained at 70 ° C. The feed rates of propylene, cyclohexylmethyldimethoxysilane, and triethylaluminum were 173 kg / H, 0.005 kg / H, and 0.015 kg / H, respectively. Hydrogen was supplied so that the hydrogen concentration in the gas phase was 4.0 mol%. The prepolymerized catalyst used in Polymerization Example 1 was slurried with liquid paraffin and fed with solid component A at 5.3 g / H. As a result of operating so that the average residence time of the reaction was 1.0H, propylene polymer IV was obtained at a production rate of 87 kg / H. It was 22.0 g / 10min when MFR of this homopolymer was measured.

Example 1
0.03 part by weight of Mg ₆ Al ₂ (OH) ₁₆ .CO ₃ .4H ₂ O (Kyowa Chemical Co., Ltd., trade name DHT-4A) as hydrotalcites with respect to 100 parts by weight of the powder of polymer II As an antioxidant, 0.05 parts by weight of tristrispentaerystoltetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Ciba Specialty Chemicals, trade name: Irganox 1010) 0.1 part by weight of-(2,4-di-tert-butylphenyl) phosphite (Ciba Specialty Chemicals, trade name: Irgaphos 168), calcium stearate as a neutralizing agent (trade name: Ca manufactured by Nitto Kasei Kogyo Co., Ltd.) 0.03 parts by weight of (St) and 2,5-dimethyl-2,5-di- (tert-butyl) as a peroxide -Peroxy) Hexane (Nippon Yushi Co., Ltd., trade name: Perhexa 25B) was mixed in 0.03 part by weight, mixed at 500 rpm for 3 minutes with a Henschel mixer, and then a φ50 mm single screw extruder (manufactured by Union Plastic) was used. A pellet-shaped polypropylene resin composition was prepared by melting, kneading, cooling and cutting under conditions of an extrusion temperature of 230 ° C. The obtained pellet had an MFR of 40 g / 10 min and a PI of 3.3.
Next, the obtained composition was used as a raw material, and melt spinning was performed using a nozzle having 24 holes. The melt spinning conditions were a spinning temperature of 230 ° C., a discharge rate of 0.8 g / min · hole, and then stretched with air soccer to obtain a fiber with a fineness of 1.8 dtex. After the fibers were accumulated on a conveyor below the air soccer ball, the fibers were fused with each other by an embossing roll set at 140 ° C. to obtain a nonwoven fabric having a basis weight of 40 g / m ² . The strength and elongation of the obtained nonwoven fabric were measured, and the standard deviation of each was determined to determine the texture. The results are shown in Table 1.

(Example 2)
0.03 part by weight of Mg ₆ Al ₂ (OH) ₁₆ .CO ₃ .4H ₂ O (Kyowa Chemical Co., Ltd., trade name DHT-4A) as hydrotalcites with respect to 100 parts by weight of the powder of polymer II As an antioxidant, 0.05 parts by weight of tristrispentaerystoltetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Ciba Specialty Chemicals, trade name: Irganox 1010) 0.1 part by weight of (2,4-di-tert-butylphenyl) phosphite (Ciba Specialty Chemicals, trade name: Irgaphos 168) and 2,5-dimethyl-2,5-peroxide as a peroxide Di- (tert-butyl-peroxy) hexane (Nippon Yushi Co., Ltd., trade name Perhexa 25B) is blended in an amount of 0.065 parts by weight, After mixing at 500 rpm for 3 minutes with an N-shell mixer, using a φ50 mm single screw extruder (manufactured by Union Plastics), melting, kneading, cooling and cutting under conditions of an extrusion temperature of 230 ° C, pellet-shaped polypropylene resin The composition was adjusted. The obtained pellet had an MFR of 63 g / 10 min and a PI of 2.8. Next, the obtained composition was used as a raw material, and melt spinning was performed using a nozzle having 24 holes. The melt spinning conditions were a spinning temperature of 230 ° C., a discharge rate of 0.8 g / min · hole, and then stretched with air soccer to obtain a fiber with a fineness of 1.8 dtex. After the fibers were accumulated on a conveyor below the air soccer ball, the fibers were fused with each other by an embossing roll set at 140 ° C. to obtain a nonwoven fabric having a basis weight of 40 g / m ² . The strength and elongation of the obtained nonwoven fabric were measured. The results are shown in Table 1.

(Example 3)
0.05 parts by weight of Mg ₆ Al ₂ (OH) ₁₆ .CO ₃ .4H ₂ O (Kyowa Chemical Co., Ltd., trade name DHT-4A) as hydrotalcites with respect to 100 parts by weight of the polymer I powder, As an antioxidant, 0.05 parts by weight of tristrispentaerystoltetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Ciba Specialty Chemicals, trade name: Irganox 1010) 0.1 part by weight of (2,4-di-tert-butylphenyl) phosphite (Ciba Specialty Chemicals, trade name: Irgaphos 168) and 2,5-dimethyl-2,5-peroxide as a peroxide 0.075 parts by weight of di- (tert-butyl-peroxy) hexane (Nippon Yushi Co., Ltd., trade name: Perhexa 25B) After mixing at 500 rpm for 3 minutes with a shell mixer, using a φ50 mm single screw extruder (manufactured by Union Plastic Co., Ltd.), melting, kneading, cooling and cutting under conditions of an extrusion temperature of 230 ° C., a pellet-shaped polypropylene resin composition I adjusted things. The obtained pellet had an MFR of 31 g / 10 min and a PI of 3.0.
Next, the obtained composition was used as a raw material, and melt spinning was performed using a nozzle having 24 holes. The melt spinning conditions were a spinning temperature of 230 ° C., a discharge rate of 0.8 g / min · hole, and then stretched with air soccer to obtain a fiber with a fineness of 1.8 dtex. After the fibers were accumulated on a conveyor below the air soccer ball, the fibers were fused with each other by an embossing roll set at 140 ° C. to obtain a nonwoven fabric having a basis weight of 40 g / m ² . The strength and elongation of the obtained nonwoven fabric were measured. The results are shown in Table 1.

Example 4
0.03 part by weight of Mg ₆ Al ₂ (OH) ₁₆ .CO ₃ .4H ₂ O (Kyowa Chemical Co., Ltd., trade name DHT-4A) as hydrotalcites with respect to 100 parts by weight of the powder of polymer III As an antioxidant, 0.05 parts by weight of tristrispentaerystoltetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Ciba Specialty Chemicals, trade name: Irganox 1010) 0.1 part by weight of (2,4-di-tert-butylphenyl) phosphite (Ciba Specialty Chemicals, trade name: Irgaphos 168) and 2,5-dimethyl-2,5-peroxide as a peroxide 0.025 part by weight of di- (tert-butyl-peroxy) hexane (Nippon Yushi Co., Ltd., trade name: Perhexa 25B) After high-speed mixing at 500 rpm for 3 minutes with a Henschel mixer, using a φ50 mm single screw extruder (manufactured by Union Plastics), melting, kneading, cooling and cutting under conditions of an extrusion temperature of 230 ° C., pellet-shaped propylene polymer The composition was adjusted. The obtained pellet had an MFR of 38 g / 10 min and a PI of 3.8.
Next, the obtained composition was used as a raw material, and melt spinning was performed using a nozzle having 24 holes. Melt spinning was performed at a spinning temperature of 230 ° C. and a discharge rate of 0.8 g / min · hole, and then stretched by air soccer to obtain a fiber having a fineness of 2.2 dtex. After the fibers were accumulated on a conveyor below the air soccer ball, the fibers were fused with each other by an embossing roll set at 140 ° C. to obtain a nonwoven fabric having a basis weight of 40 g / m ² . The strength and elongation of the obtained nonwoven fabric were measured. The results are shown in Table 1.

(Comparative Example 1)
0.03 part by weight of Mg ₆ Al ₂ (OH) ₁₆ .CO ₃ .4H ₂ O (Kyowa Chemical Co., Ltd., trade name DHT-4A) as hydrotalcites with respect to 100 parts by weight of the powder of polymer IV As an antioxidant, 0.05 parts by weight of tristrispentaerystoltetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Ciba Specialty Chemicals, trade name: Irganox 1010) 0.1 part by weight of (2,4-di-tert-butylphenyl) phosphite (Ciba Specialty Chemicals, trade name: Irgaphos 168) and 2,5-dimethyl-2,5-peroxide as a peroxide 0.018 parts by weight of di- (tert-butyl-peroxy) hexane (Nippon Yushi Co., Ltd., trade name: Perhexa 25B) After mixing at 500 rpm for 3 minutes with an N-shell mixer, using a φ50 mm single screw extruder (manufactured by Union Plastics), melting, kneading, cooling and cutting under conditions of an extrusion temperature of 230 ° C, pellet-shaped polypropylene resin The composition was adjusted. The obtained pellet had an MFR of 38 g / 10 min and a PI of 4.6.
Next, the obtained composition was used as a raw material, and melt spinning was performed using a nozzle having 24 holes. The melt spinning conditions were a spinning temperature of 230 ° C., a discharge rate of 0.8 g / min · hole, and then stretched with air soccer to obtain a fiber with a fineness of 1.8 dtex. After the fibers were accumulated on a conveyor below the air soccer ball, the fibers were fused with each other by an embossing roll set at 140 ° C. to obtain a nonwoven fabric having a basis weight of 40 g / m ² . The strength and elongation of the obtained nonwoven fabric were measured. The results are shown in Table 1.

(Comparative Example 2)
0.03 part by weight of Mg ₆ Al ₂ (OH) ₁₆ .CO ₃ .4H ₂ O (Kyowa Chemical Co., Ltd., trade name DHT-4A) as hydrotalcites with respect to 100 parts by weight of the powder of polymer I As an antioxidant, 0.05 parts by weight of tristrispentaerystoltetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Ciba Specialty Chemicals, trade name: Irganox 1010) 0.1 part by weight of-(2,4-di-tert-butylphenyl) phosphite (Ciba Specialty Chemicals, trade name: Irgaphos 168), calcium stearate as a neutralizing agent (trade name: Ca manufactured by Nitto Kasei Kogyo Co., Ltd.) 0.03 parts by weight of -St) and 2,5-dimethyl-2,5-di- (tert-butyl) as the peroxide Peroxy) hexane (Nippon Yushi Co., Ltd., trade name Perhexa 25B) is blended in 0.15 parts by weight, mixed at 500 rpm for 3 minutes with a Henschel mixer, and then extruded using a φ50 mm single screw extruder (manufactured by Union Plastics). Under the condition of a temperature of 230 ° C., a pellet-shaped polypropylene resin composition was prepared by melting, kneading, cooling and cutting. The obtained pellet had an MFR of 90 g / 10 min and a PI of 2.3.
Next, the obtained composition was used as a raw material, and melt spinning was performed using a nozzle having 24 holes. The melt spinning conditions were a spinning temperature of 230 ° C., a discharge rate of 0.8 g / min · hole, and then stretched with air soccer to obtain a fiber with a fineness of 1.8 dtex. After the fibers were accumulated on a conveyor below the air soccer ball, the fibers were fused with each other by an embossing roll set at 140 ° C. to obtain a nonwoven fabric having a basis weight of 40 g / m ² . The strength and elongation of the obtained nonwoven fabric were measured. The results are shown in Table 1.

(Comparative Example 3)
Pentaerystol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Ciba Specialty Chemicals, Inc., trade name) as an antioxidant with respect to 100 parts by weight of the polymer III powder Irganox 1010) 0.05 parts by weight Tris- (2,4-di-tert-butylphenyl) phosphite (Ciba Specialty Chemicals, trade name Irgaphos 168) 0.1 parts by weight, neutralizing agent 0.15 parts by weight of calcium stearate (manufactured by Nitto Kasei Kogyo Co., Ltd., trade name Ca-St) and 2,5-dimethyl-2,5-di- (tert-butyl-peroxy) hexane (Nippon Yushi) as peroxide Co., Ltd., trade name Perhexa 25B) is mixed with 0.025 parts by weight, and Henschel mixer is used at 500 rpm, 3 After between high speed mixing, using φ50mm single screw extruder (manufactured by Union Plastics Co., Ltd.), under conditions of an extrusion temperature of 230 ° C., molten, kneaded, cooled, and adjusted a pelletized polypropylene resin composition was cut. The obtained pellet had an MFR of 39 g / 10 min and a PI of 3.8.
Next, the obtained composition was used as a raw material, and melt spinning was performed using a nozzle having 24 holes. The melt spinning conditions were a spinning temperature of 230 ° C., a discharge rate of 0.8 g / min · hole, and then stretched with air soccer to obtain a fiber with a fineness of 1.8 dtex. After the fibers were accumulated on a conveyor below the air soccer ball, the fibers were fused with each other by an embossing roll set at 140 ° C. to obtain a nonwoven fabric having a basis weight of 40 g / m ² . The strength and elongation of the obtained nonwoven fabric were measured. The results are shown in Table 1.

(Comparative Example 4)
0.3 part by weight of Mg ₆ Al ₂ (OH) ₁₆ · CO ₃ · 4H ₂ O (Kyowa Chemical Co., Ltd., trade name DHT-4A) as hydrotalcite per 100 parts by weight of the polymer III powder As an inhibitor, 0.05 parts by weight of Tris-pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Ciba Specialty Chemicals, trade name: Irganox 1010) 0.1 parts by weight of (2,4-di-tert-butylphenyl) phosphite (Ciba Specialty Chemicals, trade name Irgafos 168), calcium stearate (manufactured by Nitto Kasei Kogyo, trade name Ca- 0.15 parts by weight of St) and 2,5-dimethyl-2,5-di- (tert-butyl) as the peroxide Peroxy) hexane (Nippon Yushi Co., Ltd., trade name Perhexa 25B) is mixed in 0.025 parts by weight, mixed at 500 rpm for 3 minutes with a Henschel mixer, and then extruded using a φ50 mm single screw extruder (manufactured by Union Plastics). Under the condition of a temperature of 230 ° C., a pellet-shaped polypropylene resin composition was prepared by melting, kneading, cooling and cutting. The obtained pellet had an MFR of 39 g / 10 min and a PI of 3.8.
Next, melt spinning was carried out using the obtained composition as a raw material and using a nozzle having 24 holes. However, many yarn breaks occurred, and fibers could not be collected.

(Comparative Example 5)
0.03 part by weight of Mg ₆ Al ₂ (OH) ₁₆ .CO ₃ .4H ₂ O (Kyowa Chemical Co., Ltd., trade name DHT-4A) as hydrotalcites with respect to 100 parts by weight of the powder of polymer I As an antioxidant, 0.05 parts by weight of tristrispentaerystoltetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Ciba Specialty Chemicals, trade name: Irganox 1010) 0.1 part by weight of (2,4-di-tert-butylphenyl) phosphite (Ciba Specialty Chemicals, trade name: Irgaphos 168) and 2,5-dimethyl-2,5-peroxide as a peroxide Di- (tert-butyl-peroxy) hexane (Nippon Yushi Co., Ltd., trade name: Perhexa 25B) was blended in 0.045 parts by weight, and After mixing at 500 rpm for 3 minutes with a shell mixer, using a φ50 mm single screw extruder (manufactured by Union Plastic Co., Ltd.), melting, kneading, cooling and cutting under conditions of an extrusion temperature of 230 ° C., a pellet-shaped polypropylene resin composition I adjusted things. The obtained pellet had an MFR of 15 g / 10 min and a PI of 3.0.
Next, melt spinning was carried out using the obtained composition as a raw material and using a nozzle having 24 holes. However, many yarn breaks occurred, and fibers could not be collected.

(Comparative Example 6)
0.03 part by weight of Mg ₆ Al ₂ (OH) ₁₆ .CO ₃ .4H ₂ O (Kyowa Chemical Co., Ltd., trade name DHT-4A) as hydrotalcites with respect to 100 parts by weight of the powder of polymer IV As an antioxidant, 0.05 parts by weight of tristrispentaerystoltetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Ciba Specialty Chemicals, trade name: Irganox 1010) 0.1 part by weight of (2,4-di-tert-butylphenyl) phosphite (Ciba Specialty Chemicals, trade name: Irgaphos 168) and 2,5-dimethyl-2,5-peroxide as a peroxide Di- (tert-butyl-peroxy) hexane (Nippon Yushi Co., Ltd., trade name Perhexa 25B) is blended in 0.1 part by weight, After mixing at 500 rpm for 3 minutes with a gel mixer, using a φ50 mm single screw extruder (manufactured by Union Plastic Co., Ltd.), melting, kneading, cooling and cutting under conditions of an extrusion temperature of 230 ° C., a pellet-shaped polypropylene resin composition Adjusted. The obtained pellet had an MFR of 170 g / 10 min and a PI of 2.9. Next, the obtained composition was used as a raw material, and melt spinning was performed using a nozzle having 24 holes. The melt spinning conditions were a spinning temperature of 230 ° C., a discharge rate of 0.8 g / min · hole, and then stretched with air soccer to obtain a fiber with a fineness of 1.8 dtex. After the fibers were accumulated on a conveyor below the air soccer ball, the fibers were fused with each other by an embossing roll set at 140 ° C. to obtain a nonwoven fabric having a basis weight of 40 g / m ² . The strength and elongation of the obtained nonwoven fabric were measured. The results are shown in Table 1.

  As is clear from Table 1, according to each of the above examples, nonwoven fabrics having good mechanical strength and good texture can be obtained (Examples 1 to 4). On the other hand, nonwoven fabrics from polypropylene resin compositions with PI values that are too large or too small are inferior in strength and elongation, and inferior in texture (Comparative Examples 1 and 2). Moreover, the nonwoven fabric from the polypropylene resin composition which does not mix hydrotalcite is inferior in strength and elongation, inferior in texture (Comparative Example 3), and from the polypropylene resin composition in which too much hydrotalcite is blended A nonwoven fabric could not be formed (Comparative Example 4). Furthermore, a nonwoven fabric cannot be molded from a polypropylene resin composition having an MFR value that is too small (Comparative Example 5), and a nonwoven fabric from a polypropylene resin composition that has an MFR value that is too large is inferior in strength and elongation, and inferior in texture. (Comparative Example 6).

  The polypropylene resin composition for long-fiber non-woven fabrics of the present invention is capable of producing a non-woven fabric having good mechanical strength and texture since MFR and PI are adjusted and hydrotalcite is added in an appropriate amount. Can be suitably used in the field of hygiene.

Claims (2)

  With 100 parts by weight of polypropylene resin, 0.005 to 0.15 parts by weight of hydrotalcite is contained, PI (polydispersity index) is in the range of 2.5 to 4.5, and melt flow A polypropylene resin composition for a long-fiber nonwoven fabric, wherein the rate is in the range of 20 to 150 g / 10 min.   A spunbonded nonwoven fabric formed by using the polypropylene resin composition for long-fiber nonwoven fabric according to claim 1.