JPH08144122A - Porous polypropylene fiber and its production - Google Patents

Abstract

PURPOSE: To obtain the subject fiber useful as a synthetic wool, non-woven fabric, woven fabric, etc., for clothes, filter material, etc., by incorporating polypropylene resin with a specific amide compound as a β-crystal nucleation agent. CONSTITUTION: The subject fiber having a satisfiable characteristics under practical condition can be produced by incorporating 100 pts.wt. of a polypropylene resin with 0.0001-5 pts.wt. (preferably 0.0005-1 pts.wt.) of an amide compound expressed by formula R<2> -NHOC-R<1> -CONH-R<3> or R<2> -CONH-R<1> -NHCO- R<3> (R<1> is a 1-24C saturated or unsaturated aliphatic dicarboxylic acid residue, etc.; R<2> and R<3> are each independently a 3-18C cycloalky, a 3-12C cycloalkenyl, etc.) (e.g. adipic acid dianilide), spinning the composition by melt-spinning and drawing the undrawn yarn containing β-crystal at a temperature between 20 deg.C and the melting point of the β-crystal.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a porous polypropylene fiber and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, the following methods have been known as methods for producing porous polypropylene fibers. That is, (1) a method in which paraffin wax is added to and mixed with polypropylene, then melt-spun, drawn, heat treated, and then the paraffin wax is extracted and removed with an organic solvent to obtain a porous fiber (WO93 / 09277). However, this method requires a complicated process such as extraction for a long time and has a problem of toxicity because an organic solvent is used.

(2) Polypropylene resin is melt-spun at a relatively high speed to obtain an unstretched fiber having crystals highly oriented in the fiber axis direction, followed by crystallization by heat treatment, and then stretching in plural times. A method of obtaining a porous fiber by carrying out the method (JP-A-4-300318). However, this method requires a long time for heat treatment before stretching, and is not practical.

(3) Crystal modification (β
Method for producing porous fiber using interfacial crystals
n. Polymer Processing IV, P337, (1991)). However, with this method, it is difficult to generate a sufficient amount of β-type crystals in the undrawn yarn at a practical spinning speed, and it is the current situation that a porous fiber having a satisfactory porosity has not been obtained. is there.

As a method for producing β-type crystals in polypropylene, a method of crystallizing molten polypropylene under a temperature gradient or a slight amount of β-crystal nucleating agent (γ-quinacridone) is used.
Method of adding and mixing (POLYMER LETTERS, 6,539-546, (196
8)) etc. have been proposed. However, the former has a drawback that it takes a long time and only a small amount of sample can be obtained. In addition, the latter method has a drawback that special equipment and operation are required for mixing with polypropylene. Further, in order to generate a certain amount or more of β-type crystals in the unstretched material, it is necessary to crystallize at a high temperature, which is not practical, and there is a problem that the product is colored red.

The present inventors have previously proposed various new β crystal nucleating agents as means for solving such problems (Japanese Patent Application No. 4-135892, Japanese Patent Application No. 4-283689, Japanese Patent Application No. 4-283689). No. 4-324807).

[0007]

The present invention is based on the above (3).
It is an object of the present invention to improve the method according to (1) and to provide a novel and useful method capable of producing a polypropylene-based porous fiber having satisfactory properties under practical conditions.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that
A melt obtained by blending a predetermined amount of an amide compound having a specific structure as a β crystal nucleating agent is melt-spun at a predetermined draft rate to obtain an unstretched fiber, and then the desired temperature is first obtained by stretching at a predetermined temperature. Find that they can achieve their goals,
The present invention has been completed based on these findings.

That is, the method for producing a porous polypropylene fiber according to the present invention is based on 100 parts by weight of the polypropylene resin, one or more amides represented by the general formula (1) or the general formula (2). A melt of a polypropylene-based resin composition containing 0.001 to 5 parts by weight of a base compound is melt-spun to obtain an undrawn yarn containing β crystals, and the undrawn yarn is converted from 20 ° C. It is characterized by stretching at a temperature up to the melting point.

R ² —NHCO—R ¹ —CONH—R ³ (1) [wherein, R ¹ is a saturated or unsaturated aliphatic dicarboxylic acid residue having 1 to 24 carbon atoms, saturated having 4 to 28 carbon atoms] Or an unsaturated alicyclic dicarboxylic acid residue or carbon number 6 to 28
Represents an aromatic dicarboxylic acid residue of. R ² and R ³ are the same or different, and are a cycloalkyl group having 3 to 18 carbon atoms, a cycloalkenyl group having 3 to 12 carbon atoms, a general formula a, a general formula b,
It represents a group represented by the general formula c or the general formula d. ]

[0011] [In the formula, R ⁴ is a linear or branched alkyl group having 1 to 12 carbon atoms, a linear or branched alkenyl group having 2 to 12 carbon atoms, or a cycloalkyl group having 6 to 10 carbon atoms. Or represents a phenyl group. ]

[0012] [In the formula, R ⁵ has the same meaning as R ⁴ in formula a. ]

[0013] [In the formula, R ⁶ represents a linear or branched alkylene group having 1 to 4 carbon atoms. ]

[0014] [In the formula, R ⁷ has the same meaning as R ⁶ in the general formula c. ]

R ⁹ —CONH—R ⁸ —NHCO—R ¹⁰ (2) [wherein R ⁸ is R ¹ in the general formula (1), R ⁹ is R ² in the general formula (1), and R ¹⁰ Are synonymous with R ³ in the general formula (1). ]

The polypropylene resin according to the present invention is a polymer containing propylene as a main constituent,
Specifically, a propylene homopolymer, a copolymer of propylene as a main component with ethylene and / or one or more 1-alkenes (including both random and block), and a propylene / ethylene multi-component copolymer (5- Examples include ethylidene-2-norbornene, 5-methylene-2-norbornene or 1,4-hexadiene), propylene-styrene copolymer, and the like. Further, a blend polymer of the above polypropylene and a small amount of a thermoplastic resin, for example, high density polyethylene, polybutene-1, poly-4-methylpentene-1, etc. is exemplified.

Melt flow rate of the polypropylene resin (hereinafter abbreviated as "MFR". JIS K 6758-1981)
Is usually about 0.1 to 50 g / 10 minutes,
It is preferably in the range of 0.3 to 10 g / 10 minutes. MF
With polypropylene having an R of more than 50, a sufficient draw ratio cannot be obtained, and it becomes difficult to obtain a porous fiber having a high porosity. On the other hand, polypropylene having an MFR of less than 0.1 has a too high melt viscosity and makes stable spinning difficult.

The amide compound represented by the general formula (1) can be easily prepared by amidating a predetermined aliphatic, alicyclic or aromatic dicarboxylic acid and a predetermined alicyclic or aromatic monoamine. Can be prepared.

As the aliphatic dicarboxylic acid, more specifically, malonic acid, diphenylmalonic acid, succinic acid, phenylsuccinic acid, diphenylsuccinic acid, glutaric acid, 3,3
-Dimethylglutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, 1,18-octadecanedioic acid and the like are exemplified.

Specific examples of the alicyclic dicarboxylic acid include 1,2-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid and 1,4-cyclohexanediacetic acid.

Specific examples of the aromatic dicarboxylic acid include p-phenylenediacetic acid, p-phenylenediethanoic acid, phthalic acid, 4-tert-butylphthalic acid, isophthalic acid, 5-tert-butylisophthalic acid and terephthalic acid. acid,
1,8-naphthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenic acid, 3,3′-biphenyldicarboxylic acid, 4,4′-biphenyldicarboxylic acid acid,
4,4′-binaphthyldicarboxylic acid, bis (3-carboxyphenyl) methane, bis (4-carboxyphenyl) methane, 2,2-bis (3-carboxyphenyl)
Propane, 2,2-bis (4-carboxyphenyl) propane, 3,3'-sulfonyldibenzoic acid, 4,4'-
Sulfonyldibenzoic acid, 3,3′-oxydibenzoic acid,
4,4'-oxydibenzoic acid, 3,3'-carbonyldibenzoic acid, 4,4'-carbonyldibenzoic acid, 3,3 '
-Thiodibenzoic acid, 4,4'-thiodibenzoic acid, 4,
4 '-(p-phenylenedioxy) dibenzoic acid, 4,
Examples thereof include aromatic dibasic acids such as 4'-isophthaloyldibenzoic acid, 4,4'-terephthaloyldibenzoic acid, and dithiosalicylic acid.

As the alicyclic monoamine, more specifically, cyclopropylamine, cyclobutylamine, cyclopentylamine, cyclohexylamine, 2-methylcyclohexylamine, 3-methylcyclohexylamine, 4-methylcyclohexylamine, 2-ethylcyclohexyl. Amine, 4-ethylcyclohexylamine,
2-propylcyclohexylamine, 2-isopropylcyclohexylamine, 4-propylcyclohexylamine, 4-isopropylcyclohexylamine, 2-te
rt-Butylcyclohexylamine, 4-n-butylcyclohexylamine, 4-isobutylcyclohexylamine, 4-sec-butylcyclohexylamine, 4-tert
-Butylcyclohexylamine, 4-n-amylcyclohexylamine, 4-isoamylcyclohexylamine, 4-sec-amylcyclohexylamine, 4-tert
-Amylcyclohexylamine, 4-hexylcyclohexylamine, 4-heptylcyclohexylamine, 4
-Octylcyclohexylamine, 4-nonylcyclohexylamine, 4-decylcyclohexylamine, 4-
Undecylcyclohexylamine, 4-dodecylcyclohexylamine, 4-cyclohexylcyclohexylamine, 4-phenylcyclohexylamine, cycloheptylamine, cyclododecylamine, cyclohexylmethylamine, α-cyclohexylethylamine, β-cyclohexylethylamine, α-cyclohexylpropylamine , Β-cyclohexylpropylamine, γ-cyclohexylpropylamine and the like.

As the aromatic monoamine, more specifically, aniline, o-toluidine, m-toluidine, p-
Toluidine, o-ethylaniline, p-ethylaniline, o-propylaniline, m-propylaniline, p
-Propylaniline, o-cumidine, m-cumidine, p
-Cumidine, o-tert-butylaniline, pn-butylaniline, p-isobutylaniline, p-sec-butylaniline, p-tert-butylaniline, pn-amylaniline, p-isoamylaniline, p- sec-amylaniline, p-tert-amylaniline, p-hexylaniline, p-heptylaniline, p-octylaniline, p-nonylaniline, p-decylaniline, p-undecylaniline, p-dodecylaniline, p- Cyclohexylaniline, o-aminodiphenyl, m-aminodiphenyl, p-aminodiphenyl, p-aminostyrene, benzylamine, α-phenylethylamine, β-
Phenylethylamine, α-phenylpropylamine,
Examples include β-phenylpropylamine and γ-phenylpropylamine.

Among the amide compounds represented by the general formula (1), particularly preferable compounds are adipic acid dianilide, terephthalic acid dicyclohexylamide and 2,6.
-Naphthalenedicarboxylic acid dicyclohexylamide and the like.

The amide compound represented by the general formula (2) amidates a predetermined aliphatic, alicyclic or aromatic diamine and a predetermined alicyclic or aromatic monocarboxylic acid according to a conventional method. Therefore, it can be easily prepared.

As the aliphatic diamine, more specifically,
1,2-diaminoethane, 1,2-diaminopropane,
1,3-diaminopropane, 1,4-diaminobutane,
Examples are 1,3-diaminopentane, 1,5-diaminopentane, 1,6-diaminohexane, 1,8-diaminooctane, 1,10-diaminodecane, and 1,11-diaminoundecane.

As the alicyclic diamine, more specifically,
1,2-diaminocyclohexane, 1,4-diaminocyclohexane, 4,4′-diaminodicyclohexyl,
4,4'-diamino-3,3'-dimethyldicyclohexyl, 4,4'-diaminodicyclohexylmethane,
In addition to 4,4′-diamino-3,3′-dimethyldicyclohexylmethane, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, etc., isophoronediamine, mensendiamine, etc. It is illustrated.

As the aromatic diamine, more specifically, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,3-diaminotoluene, 2,4-diaminotoluene, 2,6-diaminotoluene. , 3,4-diaminotoluene, 4,6-dimethyl-
m-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, 4,5-dimethyl-o-phenylenediamine, o-xylylenediamine, m-xylylenediamine, p-xylylenediamine, 2,4-diamino Mesitylene, 2,3-diaminopyridine, 2,6-diaminopyridine, 3,4-diaminopyridine, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, 2,3-
Diaminonaphthalene, 2,7-diaminonaphthalene,
9,10-diaminophenanthrene, 3,3 ′, 5
5'-tetramethylbenzidine, 3,3'-dimethyl-
4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4 '-
Methylenedi-o-toluidine, 4,4'-methylenedi-
2,6-xylidine, 4,4'-methylenedi-2,6-
Diethylaniline, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-2,2'-dimethylbibenzyl, 4,4'-diaminostilbene, 3,
4'-diamino-2,2-diphenylpropane, 4,
4'-diamino-2,2-diphenylpropane, 4,
4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-thiodianiline,
2,2'-dithiodianiline, 4,4'-dithiodianiline, 3,3'-diaminodiphenyl sulfone, 4,
4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 4,4'-diaminobenzanilide, o-tolidine sulfone, 2,7-diaminofluorene, 3,7-diamino- 2-methoxyfluorene, bis-p-aminophenylaniline, 1,3-bis (4-aminophenylpropyl) benzene, 1,4-bis (4-aminophenylpropyl) benzene, 1,3-bis (4-amino) Phenoxy) benzene, 1,4-bis (4-aminophenoxy)
Benzene, 4,4'-bis (4-aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] sulfone, 9,9-bis ( 4-aminophenyl) fluorene and the like are exemplified.

Specific examples of the alicyclic monocarboxylic acid include cyclopropanecarboxylic acid, cyclobutanecarboxylic acid, cyclopentanecarboxylic acid, 1-methylcyclopentanecarboxylic acid, 2-methylcyclopentanecarboxylic acid and 3-methylcyclopentanecarboxylic acid. Methylcyclopentanecarboxylic acid, 1-phenylcyclopentanecarboxylic acid, cyclopentenecarboxylic acid, cyclohexanecarboxylic acid, 1-methylcyclohexanecarboxylic acid, 2-methylcyclohexanecarboxylic acid, 3-methylcyclohexanecarboxylic acid, 4-methylcyclohexanecarboxylic acid, 4-propylcyclohexanecarboxylic acid, 4-butylcyclohexanecarboxylic acid,
4-pentylcyclohexanecarboxylic acid, 4-hexylcyclohexanecarboxylic acid, 4-phenylcyclohexanecarboxylic acid, 1-phenylcyclohexanecarboxylic acid, cyclohexenecarboxylic acid, 4-butylcyclohexenecarboxylic acid, cycloheptanecarboxylic acid, 1-cycloheptenecarboxylic acid Acid, 1-methylcycloheptanecarboxylic acid, 4-methylcycloheptanecarboxylic acid, cyclohexylacetic acid and the like are exemplified.

As the aromatic monocarboxylic acid, more specifically, benzoic acid, o-methyl-benzoic acid, m-methyl-benzoic acid, p-methyl-benzoic acid, p-ethyl-benzoic acid, p- Propyl-benzoic acid, p-butylbenzoic acid,
p-tert-butylbenzoic acid, p-pentylbenzoic acid, p-hexylbenzoic acid, o-phenylbenzoic acid, p
-Phenylbenzoic acid, p-cyclohexylbenzoic acid, phenylacetic acid, phenylpropionic acid, phenylbutyric acid and the like are exemplified.

Among the diamide compounds obtained from the above diamine and monocarboxylic acid, more preferable compounds are N, N'-dicyclohexanecarbonyl-p-phenylenediamine and N, N'-dibenzoyl-1,5-diaminonaphthalene. , N, N'-dibenzoyl-1,4-
Examples include diaminocyclohexane, N, N′-dicyclohexanecarbonyl-1,4-diaminocyclohexane and the like.

The applied amount of the amide compound according to the present invention is
0.001 to 100 parts by weight of polypropylene resin
5 parts by weight, more preferably 0.005 to 1 part by weight. If it is less than 0.001 part by weight, β-type crystals are unlikely to be formed in the undrawn yarn, and if it is contained in excess of 5 parts by weight, no significant difference in effect is observed.

The amide compound may be added at the time of preparing the polypropylene resin, or may be added to and mixed with a resin prepared separately.

The spinning temperature of the polypropylene resin composition is usually about 180 to 300 ° C, more preferably about 200 to 280 ° C.

The resin melt discharged at an appropriate spinning temperature preferably has a draft ratio (winding speed / discharge speed) of 30.
00 or less, more preferably 1500 or less. If the draft ratio exceeds 3000, it becomes difficult to form β-type crystals in the undrawn yarn, and it is difficult to obtain porous fibers.

The method of cooling the resin melt discharged from the nozzle in the method of the present invention is not particularly limited, but a method of cooling and solidifying by an air flow is usually appropriate. The length of the spinning cylinder is recommended to be about 2 to 6 m. Further, in order to improve the spinnability and promote the formation of β-type crystals, it is also an effective method to heat and keep the temperature directly below the spinning nozzle. Generally, the content ratio (K value) of β-type crystals in the undrawn yarn obtained at this time is about 0.5 to 1.0, which is a practical property.

The spinning nozzle used for producing the undrawn yarn in the method of the present invention is usually of a circular cross-section type, but may be of a modified cross-section type such as a Y-shaped cross section or an X-shaped cross section. .

The polypropylene undrawn yarn containing the β-type crystals prepared by the above method is drawn at a temperature from 20 ° C. to the melting point of the β-type crystals in the undrawn yarn according to a conventional method. Although the melting point of the β-type crystal in the undrawn yarn can be easily known by DSC, it varies depending on the type of raw material resin and is as high as about 150 ° C. Furthermore, in order to obtain a higher porosity, it is more preferable to draw at a temperature lower than the melting point of the β-type crystal in the undrawn yarn by 10 ° C. or more. From the standpoint of workability of stretching, it is recommended that the stretching temperature be 70 ° C or higher, preferably 90 ° C or higher. The degree of stretching is not particularly limited, but normally 1.3 to 6 times is recommended.

The polypropylene-based resin stretched fiber according to the present invention may be used in combination with a conventionally known polyolefin resin modifier as long as it does not impair the effects of the present invention, depending on the purpose of use and its application.

As such a modifier for polyolefin,
Examples thereof include various additives described in "Positive List of Additives" (October 1990) edited by the Council for Hygiene of Polyolefins, and more specifically, stabilizers (metal compounds, epoxy compounds, nitrogen). Compounds, phosphorus compounds, sulfur compounds, etc., ultraviolet absorbers (benzophenone compounds, benzotriazole compounds, etc.), antioxidants (phenolic compounds, phosphite compounds, sulfur compounds, etc.), surfactants, Lubricants (aliphatic hydrocarbons such as paraffin and wax, higher fatty acids having 8 to 22 carbon atoms, higher fatty acid metals having 8 to 22 carbon atoms (Al, Ca, M
g, Zn) salt, fatty acid having 8 to 18 carbon atoms, 8 to 2 carbon atoms
2 aliphatic alcohols, polyglycols, 4 to 2 carbon atoms
Esters of 2 higher fatty acids and aliphatic monohydric alcohols having 4 to 18 carbon atoms, higher fatty acid amides having 8 to 22 carbon atoms, silicone oil, rosin derivatives, etc., fillers (talc, hydrotalcite, mica, zeolite) , Perlite, diatomaceous earth, calcium carbonate, glass fiber, etc.), foaming agents, foaming aids, polymer additives, plasticizers, crosslinking agents,
Crosslinking accelerator, antistatic agent, antifogging agent, polymer alloy component (rubber such as block SBR or random SBR and hydrides thereof, polystyrene, etc.), flame retardant, dispersant, organic / inorganic pigment, dye, processing Various additives such as auxiliary agents are exemplified.

The polypropylene-based resin stretched fiber thus obtained has a large number of through fine pores and is excellent in bulkiness,
It is lightweight, has excellent heat retention, and has a soft texture. In addition, the fiber is excellent in water absorption and adsorption and has improved dyeability. The porous fiber is widely used in the field of clothing and various filter materials such as synthetic cotton, non-woven fabric and woven fabric. Further, the porous fiber is widely used as a carrier for various functional particles or liquids, super absorbent polymers, etc. in the fields of deodorization, water absorption, antibacterial and the like.

[0042]

EXAMPLES The present invention will be described in detail below with reference to Examples and Comparative Examples. The β-type crystal content and porosity were determined by the following methods.

[Measurement of β-Type Crystal Content] Unstretched polypropylene yarn was cut into a powder and subjected to X-ray diffraction to obtain a K value from the following formula. K value = H (β ₁ ) / [H (β ₁ ) + H (α ₁ ) + H (α ₂ )
+ H (α ₃ )] H (β ₁ ): β crystal (300) plane diffraction intensity (height) H (α ₁ ): α crystal (110) plane diffraction intensity (height) H (α ₂ ): Diffraction intensity (height) of α crystal (040) plane H (α ₃ ): Diffraction intensity (height) of α crystal (130) plane

[Porosity and Average Particle Size] The porosity was measured by a mercury porosimeter.

Examples 1 to 4 100 parts by weight of a propylene homopolymer powder having an MFR of 4.3 g / 10 min (hereinafter abbreviated as "PP (1)") was used as a β crystal nucleating agent N, N '. -Dicyclohexyl-
0.1 part by weight of 2,6-naphthalene dicarboxamide (hereinafter abbreviated as "main nucleating agent 1") is mixed with a Henschel mixer and pelletized at 240 ° C. Then, using a 30-hole nozzle having a nozzle diameter of 0.6 mm, a melt spinning machine set at 220 ° C. was used to carry out spinning at a predetermined draft ratio and winding speed to obtain an undrawn yarn. Table 1 shows the β-type crystal content (K value) of the obtained undrawn yarn.

Then, this undrawn yarn was roll-drawn at a predetermined temperature shown in Table 1 at a drawing speed of 100% per minute to obtain a drawn fiber. The stretching temperature was not higher than the melting point of the β-type crystal in the unstretched material (the melting point of the β-type crystal in PP (1) was 147 ° C. according to the DSC result). Table 1 shows the porosity and average pore diameter of the drawn fibers.

Example 5 A stretched fiber was obtained by carrying out melt spinning and drawing in the same manner as in Example 1 except that a heating and heat insulating section having a length of 1 m and an atmospheric temperature of 100 ° C. was provided immediately below the nozzle. Table 1 shows the β-type crystal content (K value) of the obtained undrawn yarn, and the porosity and average pore diameter of the drawn fiber. The melting point of the β-type crystal at this time is
It was 147 degreeC.

Example 6 A fiber was prepared in the same manner as in Example 1 except that N, N'-dicyclohexylterephthalamide (hereinafter abbreviated as "main nucleating agent 2") was used as the β crystal nucleating agent. Table 1 shows the β-type crystal content (K value) of the obtained undrawn yarn, and the porosity and average pore diameter of the drawn fiber. The melting point of the β-type crystal at this time was 147 ° C.

Example 7 A fiber was prepared in the same manner as in Example 1 except that N, N'-diphenylhexanediamide (hereinafter abbreviated as "main nucleating agent 3") was applied as the β crystal nucleating agent. Table 1 shows the β-type crystal content (K value) of the obtained undrawn yarn, and the porosity and average pore diameter of the drawn fiber. The melting point of the β-type crystal at this time was 147 ° C.

Example 8 Fibers were prepared in the same manner as in Example 1 except that N, N'-dicyclohexanecarbonyl-p-phenylenediamine (hereinafter abbreviated as "main nucleating agent 4") was used as the β crystal nucleating agent. Was prepared. Table 1 shows the β-type crystal content (K value) of the obtained undrawn yarn, and the porosity and average pore diameter of the drawn fiber. still,
At this time, the melting point of the β-type crystal was 147 ° C.

Example 9 N, N′-dibenzoyl-1,4-diaminocyclohexane as a β crystal nucleating agent (hereinafter abbreviated as “main nucleating agent 5”)
A fiber was prepared in the same manner as in Example 1 except that
Table 1 shows the β-type crystal content (K value) of the obtained undrawn yarn, and the porosity and average pore diameter of the drawn fiber. The melting point of the β-type crystal at this time was 147 ° C.

Comparative Example 1 A fiber was prepared in the same manner as in Example 1 except that the drawing temperature was 150 ° C. Β-type crystal content of the obtained undrawn yarn (K
Table 1 shows the porosity and average pore diameter of the drawn fiber). The porosity of the obtained drawn fiber showed only a small value as shown in Table 1.

Comparative Example 2 A fiber was prepared in the same manner as in Example 1 except that the β crystal nucleating agent was not used. Β-type crystal content (K value) of the obtained undrawn yarn
Table 1 shows the porosity and average pore diameter of the drawn fiber.
No β-type crystals were present in the undrawn yarn, and the obtained drawn fiber did not show porosity.

[0054]

[0055]

By applying the amide compound according to the present invention as a β crystal nucleating agent, it is possible to easily industrially produce a porous polypropylene fiber under practical conditions. The fiber is a material useful in the field of clothing and various filters such as synthetic cotton, non-woven fabric and woven fabric.

Claims (2)

[Claims] 1. A polypropylene resin containing 0.001 to 5 parts by weight of one or more amide compounds represented by the general formula (1) or (2) per 100 parts by weight of a polypropylene resin. Melt spinning of a melt of a polypropylene resin composition to obtain an undrawn yarn containing β crystals, and then drawing the undrawn yarn at a temperature from 20 ° C. to the melting point of the β crystals. Method for producing polypropylene fiber. R ² —NHCO—R ¹ —CONH—R ³ (1) [wherein, R ¹ is a saturated or unsaturated aliphatic dicarboxylic acid residue having 1 to 24 carbon atoms, saturated or unsaturated having 4 to 28 carbon atoms] Alicyclic dicarboxylic acid residue of 6 to 28 carbon atoms
Represents an aromatic dicarboxylic acid residue of. R ² and R ³ are the same or different, and are a cycloalkyl group having 3 to 18 carbon atoms, a cycloalkenyl group having 3 to 12 carbon atoms, a general formula a, a general formula b,
It represents a group represented by the general formula c or the general formula d. ] [In the formula, R ⁴ is a linear or branched alkyl group having 1 to 12 carbon atoms, a linear or branched alkenyl group having 2 to 12 carbon atoms, or a cycloalkyl group having 6 to 10 carbon atoms. Or represents a phenyl group. ] [In the formula, R ⁵ has the same meaning as R ⁴ in formula a. ] [In the formula, R ⁶ represents a linear or branched alkylene group having 1 to 4 carbon atoms. ] [In the formula, R ⁷ has the same meaning as R ⁶ in the general formula c. ^{] R 9 -CONH-R 8 -NHCO} -R 10 (2) [ wherein, the R ¹ R ⁸ in the general formula (1), R ⁹ and R ² in the general formula (1), R ¹⁰ is generally It has the same meaning as R ³ in formula (1). ] 2. A porous polypropylene fiber produced by the method according to claim 1.