JPS63256714A - Polypropylene composition for yarn - Google Patents

Abstract

PURPOSE:To obtain the titled composition having specific physical properties, capable of stably maintaining high-speed melt spinning of extremely thin yarn for a long time, by blending a propylene polymer with a hindered phenol of antioxidant, a lubricant and an organic peroxide and heat-treating the blend before spinning. CONSTITUTION:100pts.wt. powder propylene homopolymer is blended with 0.03-0.5pts.wt. hindered phenol compound (e.g. 2,6-di-6-butylparacresol) as an antioxidant, 0.03-0.5pt.wt. lubricant (e.g. calcium stearate) and 0.01-0.10pt.wt. organic peroxide (e.g. 2,5-dimethylhexane-2,5-dihydroperoxide) and before spinning is carried out, the blend is heat-treated into 25-55 melt flow rate and a Q value (weight-average molecular weight Mw/number-average molecular weight Mn) of 3-5 to give the aimed polymer composition.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a polypropylene composition for textiles. More specifically, the present invention relates to a polypropylene composition for fibers suitable for stably continuing high-speed melt spinning of ultrafine fibers for a long period of time.

(Prior art) Fibers made of synthetic resins such as polyamide, polyester, and polypropylene can be roughly divided into fibers made by drawing an undrawn spun product that is cooled and solidified after melt-spinning, and fibers made from undrawn spun products that are in a molten state after melt-spinning. There is a type of fiber that is made by pulling the material with high-speed air currents.

'L & 11, which is produced by drawing an undrawn spun product, becomes a fiber with improved strength and elasticity by drawing, and can be cut into short fibers of a desired length as stable, or as long fibers as needed. It is used in futon cotton, carpet pile, nonwoven fabrics, and knitted fabrics. Fibers drawn by high-speed airflow are drawn by high-speed airflow in the molten state of the spun product, so they are fibers produced only by high-speed drafting, and the drawn fibers do not have any strength or elasticity. By continuously and randomly distributing them as they are, it is possible to produce large quantities of fleece (sheet-like fibers), which can be used as interlining for clothing, batting for clothing, filters, civil engineering materials, agricultural materials, and medical care. It is widely used in sanitary materials, automobile interior materials, etc.

Synthetic fibers are made into fibers having various thicknesses depending on the purpose, and in recent years, so-called ultrafine fibers of 2 deniers or less have been frequently used for nonwoven fabrics.

There are many problems in producing these ultra-fine fibers.
How to make it ultra-fine, how to increase the speed to increase productivity, and how to consistently perform melt spinning in a stable manner are the key issues.
This is a big point. Resins such as polyamide and polyester have properties such as heat resistance, oxidation resistance, viscoelasticity, and crystallization speed that are suitable for stringing during melt spinning, so they can be used for high speed melt spinning of 3500 to 5000 m/sin. It is possible to produce ultrafine fibers relatively easily.

On the other hand, in the case of polypropylene, high-speed melt spinning is difficult due to its poor spinnability.Therefore, many studies have been made to obtain polypropylene for ultrafine fibers. A method to narrow the distribution, increase the melt flow rate, and improve fluidity (Japanese Patent Publication No. 4B-17613)
, and a method of controlling the molecular weight distribution by kneading peroxide into polypropylene in advance at a temperature below its thermal decomposition temperature and then melt spinning at a temperature above the thermal decomposition temperature (
JP-A No. 60-17111), crystallization rate increased by adding a crystal nucleating agent (JP-A No. 61-1F55437)
No. 2) has been proposed.

(Disclosure of the Invention) The method of narrowing the molecular weight distribution and improving fluidity by adding a specific compound containing sulfur or phosphorus to polypropylene requires a long residence time during melt spinning, etc. However, it is difficult to control the melt flow rate, and it has the disadvantage that it emits a characteristic characteristic of sulfur or phosphorus.

In the method of reacting an organic peroxide during melt spinning, melt spinning and reaction must be performed simultaneously, unreacted propylene polymer tends to remain, and it is difficult to control a narrow molecular weight distribution. In addition, a lot of gas is generated, viscous decomposition products, and solid substances are generated, and the gas generation emits a highly irritating odor and causes severe irritation to the eyes.
Deteriorate the working environment. The viscous decomposition product is a condensation of volatile components from the resin, and this viscous product is
It easily accumulates on the take-up roll or air sucker, causing melt spinning to malfunction in a short period of time. Therefore, depending on the situation, it is necessary to stop the operation several times a day and clean the spinning nozzle, take-off roll, air sucker, and spinning tube. In addition, the solid matter produced by decomposition is a solid decomposition product called burnt produced during melt spinning.
C. It accumulates on the screen pack and nozzle, increasing the spinning pressure, and this problem also requires complicated screen backing and replacement of the spinning nozzle, reducing productivity.

Polypropylene compositions reacted with organic peroxides are not easily subjected to high-speed melt spinning.

In the method of increasing the crystallization rate by adding a crystal nucleating agent, the cooling time for cooling and solidifying the spun product is short, so there is no fusion between the spun products spun from multiple nozzles. However, since the spun product from the nozzle cools and solidifies quickly, it loses its ductility, making it difficult to make ultrafine threads.

In general, fiber waste polypropylene is susceptible to deterioration due to its chemical structure due to the effects of heat and oxidation during melt spinning. Efforts are being made to stabilize the situation. However, the combination use of organic peroxides and sulfur-based compounds or phosphite-based antioxidants produces more intense gas (foul odor) and viscous decomposition products and solids than those mentioned above, so they melt quickly. The problem is to continue spinning stably for a long time.

An object of the present invention is to provide a polypropylene silk composition for wA fibers that is suitable for high-speed melt spinning of ultrafine fibers and for continuing and stabilizing this high-speed melt spinning.

The fiber waste polypropylene composition of the present invention is made of propylene polymer 100! 0.03 to 0.5 parts by weight of a hindered phenol compound as an antioxidant and 0.05 parts by weight of a lubricant per part of the amount.
03-0.5 parts by weight and 0.01-0.01 parts by weight of organic peroxide.
10 parts by weight, and heat-treated in advance prior to spinning to give a melt flow rate of 25 to 55 and a Q1 average molecular weight of 3151 (Mw/number average molecular weight Mn) of 3 to 5. It is something.

The propylene polymer used in the present invention is a crystalline polypropylene resin obtained using a commonly known Ziegler-Natsuta catalyst, and includes not only a propylene homopolymer but also a small amount of ethylene or α-olefin such as butene-1. and propylene, or a mixture of a propylene homopolymer and a copolymer. Among these polymers, the melt flow rate is 1. Those between 5 and 25 are
The heat treatment described below will reduce the melt flow rate to 25 to 5.
5. Since the Q value can be easily controlled within the range of 3 to 5, it is particularly preferred.

The antioxidants used in the present invention are limited to hindered phenol compounds, and preferably two or more kinds are used in combination. Examples of hindered phenol compounds include (a) 2
, 5-di-t-butyl para-cresol, (b) octadecyl (3,5-di-butyl-4-hydroxyphenyl) propionate, (c) tetrakis [methylene (
3,5-di-1butylhydroxyphenyl)propionate comethane, (d)1,3.15)tumethyl 2,4
,6 tris(3,5-tbutyl4hydroxybenzyl)
Benzene, (e)1,3.15-tris(3,!5-
Examples include, but are not limited to, di-butyl-4-hydroxybenzyl) isocyanurate. The total amount of the hindered phenol compound used in the present invention is 0.00 parts by weight per 1001 parts by weight of the propylene polymer.
It should be between 0.03 and 0.51 i parts. If it is less than 0.03 parts by weight, the thermal stability during melt spinning will be insufficient, and the decomposition and deterioration of the resin will proceed too much, resulting in a decrease in the continued stability of high speed spinning.

Further, if the amount exceeds 0.15 parts by weight, no increase in the amount is observed and the cost increases, which is not preferable.For combination systems of 2 or more twists, 0.07 to 0.26 parts by weight is particularly preferable.

When using a combination of two or more types of hindered phenol compounds, the amount of each component used is preferably at least 10% of the total amount used.

Examples of the lubricant used in the present invention include metal soaps and fatty acid amides. Examples of metal soaps include salts of higher fatty acids such as balmitic acid and stearic acid and alkali metals such as sodium, potassium, and lithium, or alkaline earth metals such as calcium stearate, specifically calcium stearate. , magnesium stearate, calcium 12-hydroxystearate, zinc stearate, calcium palmitate, and the like. Examples of fatty acid amides include higher fatty acid amides having 12 to 24 carbon atoms, specifically oleic acid amide, erucic acid amide, stearic acid amide, palmitic acid amide, oleyl stearylamide, and oleyl valmitylamide. These lubricants may be used alone or in combination. The amount of the lubricant used in the present invention is 1 to 1
00! The amount is 0.03 to 0.5 parts by weight. 0.
If the amount is less than 0.03 parts by weight, the lubricity is poor and there is no high-speed spinning property, and if it exceeds 0.5 parts by weight, uneven extrusion and bleed-out occur, which is not preferable. Practically 0.07-0.3
Particularly preferred is 1i parts.

Examples of the organic peroxide used in the present invention include 2,
5-dimethyl-2,5-t-butylperoxyhexene-3
Examples thereof include dialkyl peroxides such as, and sibide robber oxides such as 2,5-dimethylhexane-2,5-sibide robber oxide.

Generally, when a mixture of propylene polymer and organic peroxide is heated and reacted, the melt flow rate increases and the QI
l[ tends to decrease. Therefore, in the present invention, the amount of organic peroxide added is limited, and is 0.01 to 1 oii parts per 100 parts of propylene polymer. 0.0
If the amount is less than 11i parts, the melt flow rate cannot be raised to within a predetermined range, and the effect of lowering Q[ is insufficient. On the other hand, if it exceeds 0.10 parts by weight, the target melt flow rate will be exceeded and the stringiness will deteriorate, which is undesirable.

The heat treatment of the present invention is performed in order to react the propylene polymer and the organic peroxide and to control the melt flow rate and Q value within target ranges.

The specific heat treatment method involves mixing a propylene polymer with a hindered phenolic antioxidant, a lubricant, and an organic peroxide using a high-speed mixer, tumbler mixer, or other mixing means, and then mixing the propylene polymer with a commonly used plastic. Heat and knead using an extruder or the like. The heat treatment conditions need to be at a temperature and time that allow the organic peroxide to react sufficiently, but the specifics vary depending on the half-life temperature of the organic peroxide used, and are generally 180 to 300℃2.
minutes to 10 minutes, more preferably 230 to 270℃3 to
5 minutes is preferred; the plastic extruder is preferably equipped with a suction vent to remove gases and active decomposition products from the melt, and a fine screen pack to remove solids.

The polypropylene composition of the present invention has a melt flow rate (MFR) of 25 to 56 and a Q value of 3 to 5. This melt flow rate (MFR) indicates the ease of resin flow during melt spinning, and Qll
[(Weight average molecular weight Mw/number average molecular weight Mn) is
By keeping the melt flow rate and Q value, which indicate the state of the molecular weight distribution of the resin, within the above specified ranges, the fibers spun from the spinneret during melt spinning have appropriate tension and elasticity, and can be spun at high speed. Can be used for spinning. In other words, if the melt flow rate is less than 25, the tension during melting is too strong and high-speed spinning is not possible, and if the melt flow rate exceeds 55, the melt tension is insufficient, resulting in yarn breakage during spinning and deterioration of fiber properties such as tear strength. . Practically speaking, the melt flow rate is 30.
~45 is the most preferred, and a narrow molecular weight distribution facilitates spinning, and the Q value should be in the range of 3 to 5. If the Q value is less than 3, the processing temperature range will be narrow and thread breakage will occur easily, and if the Q value exceeds 5, the spinnability during melting will deteriorate and the spun products will be more likely to fuse together in the nozzle, resulting in ultra-fine fibers. It is particularly preferable that the fiber is difficult to spin, and furthermore, the Q value is in the range of 3.5 to 4.5.

If necessary, commonly used ultraviolet absorbers, nucleating agents, pigments, matting agents, and the like may be added to the composition of the present invention as long as the objects and effects of the present invention are not impaired.

The method for spinning the composition of the present invention includes, for example, a method in which undrawn fibers are drawn by cooling and solidifying on rotating rolls after melt-spinning and then drawn into wA fibers in the next step, or by melt-spinning from a nozzle. Thereafter, conventionally known methods can be used, such as pulling the fibers with a high-speed air stream using an air sucker or the like to form ultrafine fibers of 2 deniers or less.

As described above, since the polypropylene composition for fibers of the present invention is a composition with a limited melt flow rate and Q value, it has good spinnability and can be melt-spun at a high speed of 3500 M/win or higher. In addition, it has good heat resistance and oxidation resistance, so there is little generation of gas, active decomposition products, or solids during melt spinning, and there is little odor or severe irritation to the eyes, making it a good spinning work environment even if continued for a long time. It also does not contaminate the spinning tube, take-up roll, air sucker, etc., and the screen back and spinning nozzle need to be replaced less frequently.

Since the melt flow rate and Q value of the polypropylene composition of the present invention are already controlled within target ranges before melt spinning, the range of conditions for the spinning process: q constant can be widened. In addition, the reaction between the propylene polymer and organic peroxide has already finished before the spinning process, and gases, active decomposition products, and solid substances have decreased, so the spinning work environment is favorable and It is easy to operate continuously for a long time without contaminating the tube, take-up roll, air sucker, etc. The accumulation of solids on the screen back and nozzle is small, and the increase in spinning pressure is small, and at most 1. 4Kg/c111
2/Hr, and stable production can be achieved by melt spinning. By using the polypropylene composition of the present invention, high-speed melt spinning is easy, and even if this high-speed melt spinning is continuously operated for a long time, the yarn does not break.

(Examples) Hereinafter, the present invention will be specifically explained using Examples and Comparative Examples, but the present invention is not limited to these.

The melt flow rate and Q value of the propylene polymer and fiber composition were measured by the following methods. Note that the fiber compositions in Tables 1 and 2 refer to IIA textile polypropylene compositions obtained by heat treatment.

(1) MFR (Melt Flow Rate) According to the method according to ASTM-D I 238 conditions. (1 at 230°C2, 16kgf load
Discharge amount of molten resin for 0 minutes) (2) Qlfi (molecular weight distribution) Weight average molecular weight Mw/Number average molecular weight MnGPC method
(Ketl Beamy Sea 3 N Ri 0 Matograf (
-) Waters ALC/GPC150C type column TS -GERGMI-16-HT solvent
0-dichlorobenzene temperature 13
5° C. Detector Differential Refractometer Flow jl 1 mi/sin As for melt spinning properties, spinning speed, pressure rise, and contamination of the spinning line were investigated.

(3) Spinning speed (M/1n) The maximum speed at which spinning can be continued stably for 6 hours without yarn breakage during melt spinning is indicated by the speed of the take-up roll.

(4) Pressure increase melt spinning at the maximum speed that allows stable spinning without yarn breakage.
This is the value of the pressure rise per unit time when the pump continues for a certain period of time, measured using a pressure gauge after the gear pump.

(5) Contamination of the spinning line Melt spinning was continued for 6 hours at the maximum speed at which stable spinning could be achieved without yarn breakage, and the contamination inside the spinning cylinder, roll surface, and air sucker was examined during that time.

The O mark indicates a situation where there is no contamination.

An x mark indicates a situation where contamination is noticeable.

The fineness, strength, and elongation of the TA fibers were investigated as physical properties.

(6) Fineness The speed of the take-up roll and the discharge amount per spinning nozzle were determined and calculated.

(7) Strength and elongation The tensile strength and elongation of the fibers were examined according to JIS L1070.

Example 1 Powdered propylene homopolymer 100! A hindered phenolic antioxidant, a lubricant, and an organic peroxide listed in Table 1 below were added to each part according to the recipe shown in the same table, mixed for 2 minutes with a high-speed mixer, and then mixed in a 40 mmφ Using an extruder, the strands were melt mixed and pressed at a temperature of 250°C, the extruded strands were cooled through a cooling water tank with a length of 8 m, and then pelletized using a cold cutter.
The MFR of the polypropylene composition for fibers obtained by heat treatment to obtain the polypropylene composition for &1 is 3 days,
Q[ was 3.9.

The polypropylene composition for fibers was evaluated using a spinning machine shown in FIG. The spinning machine is a 40mmφL/D25 extruder.
2. Inside the cap, which consists of a hopper-1, a gear pump-3, a pressure gauge-4, and a cap-6, there is a screen pack-6 made of 300 mesh wire mesh and a nozzle-7. There are 200 spinning holes of , FSmmφ. There is a spinning tube-9 under the nozzle, and further below there are a take-up roll-10 and an air sucker-11.
and a collection surface-12.

The obtained polypropylene composition for fibers was charged into hopper-1 of the spinning machine shown in FIG.
It is melted in extruder 2, weighed to 151 g/win by gear pump 3, and spun out from a nozzle. The spun yarn-8 is cooled in a spinning tube-9, pulled by a take-up roll-1O, and thrown into a collecting surface-12 through an air sucker-11. Table 1 shows the results of the melt spinning properties (spinning speed, pressure increase, contamination status of the spinning line) and fiber properties.

Examples 2 to 4 Polypropylene compositions for fibers were obtained under the same conditions as in Example 1 except that the extruder was changed to an 85 mm diameter extruder with a suction vent, and according to the formulation shown in Table 1, and melt spinnability and fiber physical properties were obtained. was tested. The results are shown in Table 1.

Examples 5 to 9 Polypropylene compositions for fibers of the present invention were obtained in the same manner as in Example 1 using the various formulations shown in Table 1, and the melt spinnability and mal! ik physical properties were tested. The result is the first
Shown in the table.

Comparative Examples 1 to 7 Polypropylene compositions having formulations outside the limited range according to the present invention shown in Table 2 below were obtained, and their melt spinnability and fiber properties were tested. The results are also shown in Table 2.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of an apparatus for evaluating a polypropylene composition for fibers according to the present invention. Procedural amendment 1. Description of the case 1986 Patent Application No. 91601 2, Name of the invention Polypropylene composition for textiles 3, Person making the amendment Relationship to the case Patent applicant 3-6-32 Nakanoshima, Kita-ku, Osaka-shi, Osaka Prefecture (530 )
(207) Chisso Corporation Representative Sadao Nogi 4, Agent 2-8-1 Shinjuku, Shinjuku-ku, Tokyo (160) 5 Date of amendment order (voluntary amendment) 6 No number of inventions increased by amendment 7 , Column 8 of "Detailed Description of the Invention" of the specification to be amended, contents of the amendment (1) On page 6 of the specification, line 9, "spinning pressure" is corrected to "spinning pressure". (2) On page 18, line 14 of the specification, ``melt kneaded, pressed, extruded'' is corrected to ``melted mixed, extruded''. (3) Correct "8m" on page 18, line 15 of the specification to "4m". that's all

Claims (3)

[Claims] (1) 0.03 to 0.0% of a hindered phenol compound as an antioxidant per 100 parts by weight of propylene polymer.
5 parts by weight, 0.03 to 0.5 parts by weight of a lubricant, and 0.01 to 0.10 parts by weight of an organic peroxide. A polypropylene composition for fibers, characterized in that the weight average molecular weight Mw/number average molecular weight Mn) is in the range of 3 to 5. (2) The hindered phenol compound is (a) 2,
6-di-t-butyl para-cresol, (ro)octadecyl (3,5-di-t-butyl-4-hydroxyphenyl)
Propionate, (c) Tetrakis [methylene (3,5
-di-t-butylhydroxyphenyl)propionate]
Methane, (d)1,3,5-trimethyl-2,4,6-tris(3,5-t-butyl-4-hydroxybenzyl)benzene and (v)1,3,5-tris(3,5-di-butyl-
The polypropylene composition for fibers according to claim 1, which is a combination of two or more compounds selected from 4-hydroxybenzyl) isocyanurate. (3) The melt flow rate of propylene polymer is 1.5
25. The polypropylene composition for fibers according to claim 1, wherein the polypropylene composition has a polypropylene composition in the range of .about.25.