JPH1161554A - Highly heat-resistant polypropylene fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polypropylene fibrous material which does not melt at >=170 deg.C autoclave curing temperature, especially polypropylene fiber or yarn excellent in shape retaining property in autoclave curing at 175-180 deg.C as fibrous material for reinforcing cement. SOLUTION: This highly heat-resistant polypropylene fiber or yarn is obtained by melt-molding a polypropylene resin composition obtained by adding 0.001-5 pts.wt. nucleating agent forming β crystal to 100 pts.wt. homopolypropylene having >=96% isotactic pentad fraction and satisfying 0.3-30 g/10 min melt flow rate and drawing the molded material. In the fiber or yarn, the fiber shape is retained even in autoclave curing at 180 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to high heat resistant polypropylene fibers or yarns, and more particularly to cement reinforcing fibers or yarns.

[0002]

2. Description of the Related Art Conventionally, asbestos has been used as a fiber for reinforcing cement. However, asbestos has been restricted in use because it has a bad effect on the human body, and polyolefin fibers have recently begun to be used as a substitute for this. Cement requires a curing process at the stage of its forming. Curing in an autoclave (10 kgf / cm ² ) 170 ~
This is performed at 180 ° C. for several tens of hours. However, since ordinary polypropylene fibers have a melting point of 160 to 165 ° C., they cannot withstand this curing and are melted, which causes a problem that polypropylene does not exist as a fiber in concrete after curing. If the curing temperature of the concrete is lowered to 165 to 170 ° C., curing can be performed without melting the polypropylene fiber. However, this requires a long time for curing and lowers productivity.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide, as a fiber reinforcing material for cement, a polypropylene fibrous material which does not melt at an autoclave curing temperature of 170 ° C. or more, and particularly an autoclave curing at 175 to 180 ° C. It is intended to provide a novel polypropylene fiber or yarn which is sometimes excellent in shape retention.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, by adding a β crystal nucleating agent to polypropylene having a specific stereoregularity, high heat resistance is obtained. The present inventors have found that polypropylene fibers can be obtained, and have completed the present invention. That is, the present invention provides a nucleating agent for forming β crystals in 100 parts by weight of homopolypropylene having an isotactic pentad fraction of 96% or more and a melt flow rate of 0.3 to 30 g / 10 min. It is a high heat-resistant polypropylene fiber or yarn obtained by melt-molding a polypropylene resin composition to which about 5 parts by weight has been added and then stretching.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Polypropylene resin The polypropylene resin in the present invention has an isotactic pentad fraction (hereinafter, referred to as IPF) as an index of stereoregularity of 96% or more and a melt flow rate (hereinafter, referred to as MFR) of 0.3 to 30. Filling homopolypropylene. If the IPF is less than 96%, the melting temperature of the polypropylene resin and its molded product is low, which is not preferable as a cement reinforcing material. If the MFR is less than 0.3, the pressure at the die outlet is excessively increased during melt molding (mainly, fiber spinning), which is not preferable.
On the other hand, if the MFR exceeds 30, the high molecular weight component in the polypropylene decreases, and the oriented fiber or yarn has less oriented crystals. As a result, the melting temperature of the fiber or yarn decreases, which is not preferable as a cement reinforcing material. Furthermore,
The molecular weight distribution (Mw / Mn) of polypropylene is 3.5
To 12 are preferable, and 4 to 9 are particularly preferable.

[0006] 2. β crystal nucleating agent The nucleating agent used to form β crystals used in the present invention is one or more amide compounds represented by the general formula (1) or (2). R ² -NHCO-R ¹ -CONH-R ³ (1) wherein R ¹ is a saturated or unsaturated aliphatic carboxylic acid residue having 1 to 24 carbon atoms, and a saturated or unsaturated residue having 4 to 28 carbon atoms Represents an alicyclic dicarboxylic acid residue or an aromatic dicarboxylic acid residue having 6 to 28 carbon atoms. R ² and R ³ are the same or different and are a cycloalkyl group having 3 to 18 carbon atoms,
To 12 cycloalkenyl groups, groups represented by general formula a, general formula b, general formula c or general formula d. ]

[0007]

Embedded image [Wherein, R ⁴ represents a linear or branched alkyl group having 1 to 12 carbon atoms, a linear or branched alkenyl group having 2 to 12 carbon atoms, a cycloalkyl group having 6 to 10 carbon atoms, or phenyl. Represents a group. ]

[0008]

Embedded image [Wherein, R ⁵ has the same meaning as R ⁴ in formula (a)]. ]

[0009]

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

[0010]

Embedded image [Wherein, R ⁷ has the same meaning as R ⁶ in 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 and R ¹⁰ in the general formula (1) Has the same meaning as R ³ in formula (1). Specifically, N, N'-dicyclohexyl-2,6-naphthalenedicarboxamide, N, N'-dicyclohexylterephthalamide, N, N'-diphenylhexanediamide, N, N'-dicyclohexanecarbonyl-p
Phenylenediamine, N, N'-dibenzoyl-1,
4-diaminocyclohexane and the like.
Ngesta from Shin-Nippon Rika Co., Ltd. as a crystal nucleating agent
(Product name).

In the present invention, the amount of the β crystal nucleating agent is 0.001 to 5 parts by weight, preferably 0.005 to 1 part by weight, based on 100 parts by weight of the polypropylene resin. 0.0
If the amount is less than 01 parts by weight, β crystals are hardly generated in the undrawn yarn or the yarn, and if the amount exceeds 5 parts by weight, the superiority of the effect is not recognized, and conversely, the yarn breaks during spinning. The nucleating agent may be added at the time of preparing the polypropylene resin, or may be added to a separately prepared resin.

3. Other additives In the polypropylene resin drawn fiber or yarn of the present invention,
Conventionally known modifiers for polyolefins can be used in combination depending on the purpose of use. For example, antioxidants, ultraviolet absorbers, light stabilizers, organic carboxylic acids, antistatic agents, surfactants, neutralizers, dispersants, epoxy stabilizers, plasticizers, lubricants, antibacterial agents, flame retardants, fillers, Foaming agents, foaming assistants, crosslinking agents, crosslinking assistants, pigments and the like. Examples of the antioxidant include a phenolic antioxidant, a phosphorus-based antioxidant, a sulfur-based antioxidant, an amine-based antioxidant, and vitamins. Neutralizing agents that also serve as dispersants include metal soaps,
Examples include hydrotalcites, lithium aluminum composite hydroxide salts, silicates, metal oxides, metal hydroxides, and the like. Further, in order to improve the dispersibility of fibers or yarns in cement, a hydrophilic polymer such as polyethylene glycol and polyethylene oxide is used in an amount of 0.1 to 2%.
It is also effective to add within the range of 0 parts by weight.

4. Method for Producing Polypropylene Fiber or Yarn (1) Production of Unstretched Molded Article Unstretched fiber is molded by melt molding, generally by melt extrusion molding. For example, a filament for drawing is obtained by melt-extruding polypropylene through a spinneret,
In addition, a yarn for drawing can be obtained by extruding polypropylene through a flat die or a ring die.
Further, by performing cutting after forming the blown film, a split yarn for stretching can be obtained. Β of the present invention
In order to improve the stretchability of the unstretched polypropylene molded article thus obtained using the crystal nucleating agent-containing polypropylene composition, it is preferable to further promote β-crystallization of the crystal system of the unstretched molded article. For that purpose, it is desirable to relatively slowly cool the undrawn filament or the yarn during molding. It is also an effective method to promote the formation of β crystals by heating and keeping the temperature directly below the spinning nozzle.

(2) Stretching operation The stretching operation can be performed in one stage or in two or more stages. The stretching temperature is in the range of 70 to 150 ° C., and the heat treatment is performed in an oven, a hot plate, far infrared rays, or the like. The draw ratio is 1.5 to 10 times, preferably 2 to 7 times in the case of fiber,
In the case of yarn, it is 2 to 16 times, preferably 4 to 14 times.

(3) Heat Treatment The thus obtained polypropylene fiber or yarn can be subjected to a heat treatment (under constrained conditions) if desired. This heat treatment is generally carried out at a temperature of 140 to 170 ° C., preferably 150 to 165 ° C., for 0.5 to 30 minutes, preferably 1 to 20 minutes. By this heat treatment, the crystallization of the oriented crystal part progresses, and the melting point is further increased. In the case of autoclave curing, the temperature is gradually increased to the target temperature of 170 to 180 ° C. over 2 to 5 hours, and as a result, the situation is the same as when the polypropylene fiber is subjected to the heat treatment. Therefore, the heat treatment may be performed at the time of autoclave curing.

5. The fiber or the yarn of the present invention is applied as a cement reinforcing material.As the cement to which the fiber or the yarn of the present invention is applied as a cement reinforcing material, for example, usually Portland cement, white Portland cement, alumina cement,
Examples thereof include hydraulic cements such as silica cement, magnesia cement and pozzolan cement, air-hardening cements such as gypsum and coal, and special cements such as acid-resistant cements. In addition, as the cement composition using the cement, for example, one or more of the above-described cements, calcium carbonate, inorganic materials such as magnesium hydroxide or titanium white, and pebbles, sand, and the like as necessary. It can be obtained by mixing an aggregate, a paraffin, a wax, a thermosetting water-soluble resin such as a resol type phenol resin, various polymer emulsions, a curing accelerator, a curing retarder, a water reducing agent and the like. When the cement composition is hardened, the mixing ratio of cement and water when adding water to the cement composition, that is, the so-called C / W ratio is preferably in the range of 1 to 10. C / W ratio is 1
Below, the amount of water becomes too large, and the strength of the cement hardened product is not sufficiently increased. If it is more than 10, the fluidity of the cement composition is deteriorated.

6. Usage Mode of Using the Fiber or Yarn of the Present Invention as a Cement Reinforcing Material When using the fiber or yarn of the present invention as a cement reinforcing material, the form used depends on the shape of the fiber or the yarn. If yarn is used as cement reinforcement,
At a stage where the cement composition is not completely cured, a method of fixing the cement reinforcing material according to the present invention to a semi-cured cement composition with a rock bolt or the like and further supplying the cement composition is used.

When the fiber is used as the cement reinforcing material, the cement reinforcing fiber is preferably cut into a length of about 3 to 30 mm and then mixed with the cement composition. In this case, if the fiber length is longer than 30 mm, it becomes difficult to uniformly disperse in the cement composition, and if it is shorter than 3 mm, a sufficient reinforcing effect may not be obtained. As for the amount of the fiber cement reinforcing material to be mixed, if the amount of the fiber cement reinforcing material is too small, a sufficient reinforcing effect cannot be obtained, and if the amount is too large, the cement reinforcing material is difficult to be uniformly dispersed. Therefore, for 100 parts by weight of the cement composition, the mixing amount of the cement reinforcing fiber is in the range of 0.5 to 30 parts by weight,
More preferably, it is 1 to 15 parts by weight.

[7] FIG. Cement products using fibers or yarns of the present invention as cement reinforcements The various products obtained by applying the fibers or yarns of the present invention as a cement reinforcement to the above cement composition include various cement products. Examples include underwater structures such as tetrapods, road and railway structures such as bridges and tunnels, structures such as buildings, houses and walls, seawall blocks, and tiles.

[0021]

The present invention will be described below in detail with reference to examples.
The test method in the examples is as follows. (1) IPF: Macromolecules, 6 , 9
Was determined by ¹³ C-NMR spectroscopy according to 25 (1973). That is, a peak fraction corresponding to isotactic bonding was determined from peaks indicating five consecutive propylene monomer units in the ¹³ C-NMR spectrum.
Peak assignments were made using Macromolecules, 8 ,
687 (1975). (2) MFR: Load 2.1 according to JIS K7210
It was measured at 6 kg and 230 ° C. (3) DSC measurement: About 10 mg of a sample (drawn fiber or yarn) was measured by increasing the temperature from room temperature to 210 ° C. at a scanning temperature of 10 ° C./min. (4) Molecular weight distribution: measured by GPC. (5) Spinnability: A case where three or more yarns out of 30 yarns were broken during continuous 60-minute spinning was evaluated as x. (6) Evaluation of maximum stretching ratio: In the stretching step, the upper limit was set to a value at which yarn breakage due to stretching for 20 minutes did not occur. (7) Fiber morphology evaluation method after curing in an autoclave: The concrete test piece after curing was divided, and the fiber shape remaining in the cross section was evaluated. That is, ○ indicates that almost all remained in the fibrous state, Δ indicates that the fiber remained to about half, and X indicates that no half remained.

Example 1 Ir1010 and Ir168 (manufactured by Ciba Geigy) as antioxidants were added to 100 parts by weight of homopolypropylene having an IPF of 96%, an MFR of 2 g / 10 min, and a molecular weight distribution (Mw / Mn) of 6. After adding 0.05 parts by weight, 0.05 parts by weight of calcium stearate as a neutralizing agent, and 0.1 parts by weight of N-gester (Nippon Rika Co., Ltd.) as a neutralizing agent, and blending using a super mixer. , 50
The mixture was melt-kneaded at 230 ° C. and a screw rotation speed of 75 rpm with an extruder having a diameter of mm to obtain a polypropylene pellet.

This was melt-spun using a multifilament spinning machine with a gear pump (die: 0.8 mmφ × 30 holes) at a spinning temperature of 290 ° C. and a winding speed of 300 m / min.
An undrawn yarn of about 20 denier was obtained. Next, stretching was performed under the conditions of a feed speed of 50 m / min, a feed roll temperature of 90 ° C, a heater temperature of a stretching point of 130 ° C, and a draw roll temperature of 110 ° C. The maximum draw ratio is 5 times and 4.5.
A double drawn yarn was obtained. After cutting the drawn fiber obtained as described above to a length of 15 mm, Portland cement (manufactured by Chichibu Onoda Co., Ltd.), No. 8 silica sand and water are used in a weight ratio of Portland cement: silica sand: water = 100: 100. : 60 was mixed into the cement composition. The mixing ratio of the cement composition and the fibrous cement reinforcing material was set to be cement composition: fibrous cement reinforcing material = 100: 1 by weight.

The cement-fibrous cement reinforcing material mixture obtained as described above was used for a length of 80 mm and a width of 30 m.
m and a height of 20 mm were poured into a mold and subjected to the following normal-pressure steam curing for one day and then to autoclave curing for one day. Atmospheric pressure steam curing: After curing at 23 ° C. for 2 to 5 hours, 65
After raising the temperature to 20 ° C. at a rate of 20 ° C./hour, isothermal curing for 3 to 5 hours. Then slowly cool to 23 ° C over 10-15 hours. Autoclave curing: After demolding, put into autoclave pot. Heating to 180 ° C. and 10 atm over 3 to 6 hours,
After pressing, isothermal isobar for 3-5 hours. After that, water was applied to the space on the outer wall of the kettle and cooled for 7 to 10 hours.

The melting peak and end temperature of the fibrous cement reinforcing material itself were 180 ° C. and 1
At 84 ° C., a remarkable increase in the melting point was observed as compared with the conventional art. As a result, it was confirmed that the fiber form was maintained even after the autoclave curing at 180 ° C. Table 1 shows the results.

Examples 2 to 4 Except that the amount of β crystal nucleating agent Engester was 0.005, 1, and 5 parts by weight, the stretching ratio was 4 to 4 in the same manner as in Example 1.
A 4.5-fold fibrous cement reinforcing material was obtained, and a test sample was obtained in the same manner as in Example 1. As a result, the melting peak and the termination temperature by DSC measurement were 176 to 180, respectively.
℃, 180 to 184 ℃ marked melting point rise,
It was confirmed that the fiber form was maintained even after autoclaving at 0 ° C. Table 1 shows the results.

Example 5 A fibrous cement having a draw ratio of 4.2 times in the same manner as in Example 1 except that a homopolypropylene having an IPF of 96.3%, an MFR of 2 g / 10 min, and a molecular weight distribution of 12 was used. A reinforcing material was obtained, and a test sample was obtained in the same manner as in Example 1. As a result, the melting peak and the termination temperature by DSC measurement were markedly increased to 181 ° C. and 184 ° C., respectively, and it was confirmed that the fiber morphology was maintained even after the autoclave curing at 180 ° C. Table 1 shows the results.

Example 6 A fiber having a draw ratio of 5.5 times in the same manner as in Example 1 except that a homopolypropylene having an IPF of 97.0%, an MFR of 15 g / 10 min, and a molecular weight distribution of 6.2 was used. A cementitious reinforcing material was obtained, and a test sample was obtained in the same manner as in Example 1. As a result, the melting peak and the end temperature by DSC measurement were markedly increased to 177 ° C. and 181 ° C., respectively, and it was confirmed that the fiber morphology was maintained even after autoclaving at 180 ° C. Table 1 shows the results.

Example 7 A fibrous cement having a draw ratio of 6 times in the same manner as in Example 1 except that a homopolypropylene having an IPF of 97.3%, an MFR of 30 g / 10 min, and a molecular weight distribution of 4.5 was used. A reinforcing material was obtained, and a test sample was obtained in the same manner as in Example 1. As a result, the melting peak and the termination temperature by DSC measurement were 176 ° C. and 180 ° C., respectively, and markedly increased melting points, and it was confirmed that the fiber form was maintained even after autoclaving at 180 ° C. Table 1 shows the results.

Comparative Example 1 Example 1 was repeated except that homopolypropylene having 92.0% of IPF, MFR of 2 g / 10 min, and molecular weight distribution of 6 was used.
In the same manner as in Example 1, a fibrous cement reinforcing material having a draw ratio of 4.5 was obtained, and in the same manner as in Example 1, a test sample was obtained.
As a result, it was confirmed that the melting peak was 160 ° C. and the ending temperature was 165 ° C., respectively, which was low by the DSC measurement, and the fiber morphology was not maintained after the autoclave curing at 180 ° C. Table 1 shows the results.

Comparative Example 2 A homopolypropylene having an IPF of 96.8%, an MFR of 100 g / 10 min and a molecular weight distribution of 6.2 was used.
A fibrous cement reinforcing material having a draw ratio of 6.5 times was obtained in the same manner as in Example 1, and a test sample was obtained in the same manner as in Example 1. As a result, the melting peak and the end temperature by DSC measurement were 166 ° C. and 169 ° C., respectively, and the melting point was low.
After the autoclave curing at 0 ° C., it was confirmed that the fiber form was not maintained. Table 1 shows the results.

Comparative Example 3 A fibrous cement reinforcing material having a draw ratio of 4.5 times was obtained in the same manner as in Example 1 except that the amount of β crystal nucleating agent Engester was changed to 8 parts by weight. A test sample was obtained in the same manner as described above. As a result, a melting peak by DSC measurement,
The end temperatures are 180 ° C and 184 ° C, respectively, and the melting points are high,
It was confirmed that the fiber form was maintained after the autoclave curing at 180 ° C., but there was a problem in spinnability such as frequent yarn breakage during spinning. Table 1 shows the results.

Comparative Example 4 A fibrous cement reinforcing material having a draw ratio of 3.2 times was obtained in the same manner as in Example 1 except that the amount of the β crystal nucleating agent Engester was changed to 0.0007 parts by weight. A test sample was obtained in the same manner as in Example 1. As a result, the melting peak and end temperature by DSC measurement were 172 ° C. and 176 ° C., respectively.
After autoclaving at 180 ° C., the fiber morphology was poor in retention. Table 1 shows the results.

Comparative Example 5 A fibrous cement reinforcing material having a draw ratio of 3 times was obtained in the same manner as in Example 1 except that 0.2 parts by weight of a sorbitol-based nucleating agent was used instead of the β nucleating agent Ngester. A test sample was obtained in the same manner as in Example 1. As a result, DSC
Melting peak by measurement, end temperature is 171 ℃, respectively
After autoclaving at 176 ° C. and 180 ° C., the fiber morphology was poor in retention. Table 1 shows the results.

Comparative Example 6 The procedure of Example 1 was repeated, except that 0.2 parts by weight of a phosphorus-based nucleating agent NA11 (manufactured by Asahi Denka Kogyo KK) was used instead of the β crystal nucleating agent Ngester. A fibrous cement reinforcing material having a draw ratio of 3 times was obtained, and a test sample was obtained in the same manner as in Example 1. As a result, a melting peak by DSC measurement,
The termination temperatures were 172 ° C. and 177 ° C., respectively, and after the autoclave curing at 180 ° C., the fiber form retention was not good. Table 1 shows the results.

Comparative Example 7 Using homopolypropylene having an IPF of 97.0%, an MFR of 15 g / 10 min, and a molecular weight distribution of 6.2, a sorbitol-based nucleating agent was used in place of β-nucleating agent Engester.
Except for using parts by weight, a stretching ratio of 4 was obtained in the same manner as in Example 1.
A double fibrous cement reinforcement was obtained, and a test sample was obtained in the same manner as in Example 1. As a result, the melting peak and the end temperature by DSC measurement were 171 ° C. and 175, respectively, and the melting points were low, and it was confirmed that the fiber morphology was not maintained after the autoclave curing at 180 ° C. Table 1 shows the results.

Comparative Example 8 IPF 97.1%. Homopolypropylene having an MFR of 30 g / 10 min and a molecular weight distribution of 4.5 was used, and instead of the β crystal nucleating agent Ngester, NA11 which was a phosphorus-based nucleating agent was used.
(Asahi Denka Kogyo Co., Ltd.) except that 0.2 parts by weight was used.
A fibrous cement reinforcing material having a draw ratio of 4.5 times was obtained in the same manner as in Example 1, and a test sample was obtained in the same manner as in Example 1. As a result, the melting peak and the end temperature by DSC measurement were 172 ° C. and 176 ° C., respectively, and the melting points were low,
After the autoclave curing at 0 ° C., it was confirmed that the fiber form was not maintained. Table 1 shows the results.

[0038]

[Table 1]

Example 8 An inflation film was formed from the pelletized polypropylene prepared in Example 1 at an extrusion temperature of 230 ° C. and a blow-up ratio of 0.90, and was cut in the width direction and stretched. . Stretching: hot plate 135 ° C, heat setting (heat treatment) temperature 150 ° C, take-up roll speed 1
The stretching ratio was determined by adjusting the feeding roll speed to 00 m / min. Thus, a 12-fold drawn yarn was obtained at a maximum draw ratio of 13 times. A test sample was obtained in the same manner as in Example 1 using the drawn yarn as a cement reinforcing material.

As a result, the melting peak and end temperature of the stretched tape measured by DSC were 180 ° C. and 183 ° C., respectively, and the melting points were high, and it was confirmed that the fiber form was maintained after the autoclave curing at 180 ° C. Table 2 shows the results.

Examples 9 to 11 Except that the β crystal nucleating agent Engester was added in an amount of 0.005, 1, or 5 parts by weight, the stretching ratio was 12 in the same manner as in Example 8.
A １12.5 times yarn-like cement reinforcement was obtained, and a test sample was obtained in the same manner as in Example 1. As a result, DS
The melting peak and the end temperature of the reinforcing material by C measurement show remarkable melting point increases of 177 to 180 ° C. and 181 to 183 ° C., respectively, and it is confirmed that the shape is maintained even after the autoclave curing at 180 ° C. Was. Table 2 shows the results.

Example 12 A yarn-like cement having a draw ratio of 13 times was produced in the same manner as in Example 8 except that a homopolypropylene having an IPF of 97.0%, an MFR of 15 g / 10 min, and a molecular weight distribution of 6.2 was used. A reinforcing material was obtained, and a test sample was obtained in the same manner as in Example 1. As a result, the melting peak and the end temperature by DSC measurement showed remarkable rises in melting point of 177 ° C. and 181 ° C., respectively, and it was confirmed that the shape was maintained even after the autoclave curing at 180 ° C. Table 2 shows the results.

Comparative Example 9 Example 8 except that homopolypropylene having an IPF of 92.0%, an MFR of 2 g / 10 min, and a molecular weight distribution of 6 was used.
In the same manner as in Example 1, a yarn-like cement reinforcing material having a draw ratio of 12.5 was obtained, and in the same manner as in Example 1, a test sample was obtained. As a result, the melting peak and end temperature by DSC measurement were 162 ° C. and 167 ° C., respectively, and the melting points were low, and 180 ° C.
It was confirmed that the fiber form was not retained even after the autoclave curing in the above. Table 2 shows the results.

Comparative Example 10 With a homopolypropylene having an IPF of 96.8%, an MFR of 100 g / 10 min, and a molecular weight distribution of 6.2, it was not possible to form an inflation film and the evaluation was not possible. Table 2 shows the results.

Comparative Example 11 A sorbitol-based nucleating agent was used in place of Ngester.
Except for using 2 parts by weight, a yarn-like cement reinforcing material having a draw ratio of 8 was obtained in the same manner as in Example 8, and a test sample was obtained in the same manner as in Example 1. As a result, the melting peak and the end temperature by DSC measurement were 170 ° C. and 175, respectively.
After autoclaving at 180.degree. C. and 180.degree. C., the shape retention was poor. Table 2 shows the results.

Comparative Example 12 A yarn-like cement reinforcing material having a draw ratio of 8 was obtained in the same manner as in Example 8, except that NA11 was used instead of NA11 in an amount of 0.2 part by weight. To obtain a test sample. As a result, the melting peak and end temperature by DSC measurement were 172 ° C. and 176 ° C., respectively,
After autoclaving at ℃, the retention of its morphology was poor. Table 2 shows the results.

Comparative Example 13 Homopolypropylene having an IPF of 97.0%, an MFR of 15 g / 10 min and a molecular weight distribution of 6.2 was used, and the sorbitol-based nucleating agent was replaced with 0.2 parts by weight in place of Ngester. Except for the above, a yarn-like cement reinforcing material having a draw ratio of 8 was obtained in the same manner as in Example 8, and a test sample was obtained in the same manner as in Example 1. As a result, the melting peak and the end temperature by DSC measurement were 171 ° C. and 175 ° C., respectively, and the melting points were low, and it was confirmed that the form was not retained after autoclaving at 180 ° C. Table 2 shows the results.

[0048]

[Table 2]

[0049]

The polypropylene fiber or yarn of the present invention is a high heat-resistant fiber or yarn obtained from a composition obtained by adding a β crystal nucleating agent to polypropylene having a high stereoregularity. The fiber form is maintained even under severe curing, and the effect can be sufficiently exhibited as a cement reinforcing material.

Claims (2)

[Claims] An isotactic pentad fraction of 96% or more and a melt flow rate of 0.3 to 3
A heat-resistant polypropylene fiber or yarn obtained by melt-molding a polypropylene resin composition obtained by adding 0.001 to 5 parts by weight of a nucleating agent for forming β crystals to 100 parts by weight of homopolypropylene satisfying 0 g / 10 minutes and then stretching. . 2. The highly heat-resistant polypropylene or yarn according to claim 1, which is used as a cement reinforcing fiber.