JPH03260111A - Preparation of ultrahigh molecular weight polypropylene drawn product - Google Patents

Abstract

PURPOSE:To prepare the subject product having a high strength, a large elongation at breakage and a large energy absorption by adding a diluent to an ultrahigh mol.wt. PP composition consisting of ultrahigh mol.wt. PP and an alpha-olefinic polymer, melt-blending followed by extruding the blended product from a die and subsequently drawing the extruded product. CONSTITUTION:An ultrahigh mol.wt. PP composition consisting of 50-99 pts.wt., preferably 60-90 pts.wt., of ultrahigh mol.wt. PP having an intrinsic viscosity [eta]of >=5dl/g, preferably >=10dl/g, and 1-50 pts.wt., preferably 10-40 pts.wt., of an alpha-olefinic polymer derived from a 4-18C alpha-olefin and having an intrinsic viscosity of >=5dl/g, preferably 12.5dl/g, is melt-blended with a diluent (preferably an aliphatic hydrocarbon derivative having a melting point of 40-100 deg.C, e.g. a wax), extruded from a die and subsequently drawn to provide the objective product.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for producing a stretched molded article of a resin composition containing ultra-high molecular weight polypropylene, and more specifically,
The present invention relates to a method for producing an ultra-high molecular weight polypropylene stretched molded article that has high strength, a large elongation at break, and a large amount of energy absorption until breaking.

Technical Background of the Invention It is already known that by forming ultra-high molecular weight polyethylene into fibers or tapes, etc. and stretching this, a stretched molded article having high elastic modulus and high tensile strength can be obtained. The patent has been published.

For example, JP-A-58-15.408 discloses a method related to the so-called gel spinning/ultra-stretching method, in which a dilute solution of ultra-high molecular weight polyethylene is spun and then the resulting filaments are stretched. .

Furthermore, JP-A No. 58-5228 discloses that a dilute solution of an ultra-high molecular weight thermoplastic crystalline polymer was prepared using a non-volatile method, and this was spun to form xerogel fibers. Later, a method of stretching is shown. This method is basically the same as the gel spinning/ultra-stretching method described above, but by using ultra-high molecular weight polyethylene, it has an elastic modulus of 100 GPa or more and a tensile strength of 3 GPa or more. A stretched bottom shape with high elastic modulus and high strength can be obtained.

In this way, in the case of ultra-high molecular weight polyethylene,
A method for producing fibers with high elastic modulus and high tensile strength using a dilute solution as a medium has almost been established, and its principles are described in the Journal of the Japanese Society of Rheology (Matsuo, Vol.
, 13. No, 1. P4-15°1, 985).

Utilizing such techniques in ultra-high molecular weight polyethylene, numerous studies have been conducted to obtain fibers with high elastic modulus and high tensile strength from ultra-high molecular weight polypropylene.

For example, Hokugi et al. applied the successful zone stretching method for polyethylene to polypropylene to achieve a molecular weight of 47.5%.
By stretching 10,000 mm of polypropylene, 16°90
Polypropylene fibers with an elastic modulus of P a and a tensile strength of 0.74 GPa have been obtained (Journal
orAppljed PolymerScience,
Vol, 2B, PI79-189.1983), Koni Tezon drawing method refers to the 1-2I! In this method, super-stretching is performed by heating the l+1 portion using a local heating furnace and stretching the portion. In addition, as an example of applying the gel fiber/ultra-stretching method described above to polypropylene, Peg
y and Manley's report (PolymerCotpmu
nications, Vol. 25. P2O~42
, 19g4), and they are Smlth and Lems.
Journal of Polymer But Ie
Gel spinning and super-stretching were performed using a 0.75 to 1.5 wt% solution using a method similar to that of Tin, Vol.
Polypropylene fibers with a tensile strength of 3 GPa are obtained.

Furthermore, JP-A-58-5,228 also discloses examples of polypropylene as well as the examples of polyethylene described above, and the intrinsic viscosity [ηJ 1g
dll/g (molecular weight 3.3 million) from a solution with a concentration of 6% by weight, the elastic modulus is 23.9.
GPa and a tensile strength of 1.04 GPa.

However, when examining ultra-high molecular weight polypropylene fibers or tapes obtained by methods using conventional methods for preparing ultra-high molecular weight polyethylene fibers, it was found that ultra-high molecular weight polypropylene fibers or tapes obtained using any of the methods The elastic modulus of polypropylene drawn yarn or tape is 7~
Approximately 100 Pa, tensile strength is 0.5 to 1.04 GP
It is about a.

By the way, the theoretical strength of ultra-high molecular weight polyethylene is 32G.
The theoretical strength of ultra-high molecular weight polypropylene is about 18 GPa, and the theoretical strength of ultra-high molecular weight polypropylene is 172
It is already known that the
Vol, 40. P, 407-418.1984). At present, tensile strength of about 6 GPa has already been obtained for ultra-high molecular weight polypropylene fibers, and from this value, the tensile strength of 0.5 to 1.04 GPa for ultra-high molecular weight polypropylene fibers is This is not necessarily a satisfactory value. That is, for ultra-high molecular weight polypropylene, the tensile strength is 3G.
Based on this value, the actual situation is that the tensile strength has hardly been improved.

By the way, an example of some success in improving ultra-high molecular weight polypropylene is the method reported by Kanemoto et al.
Journal of the Japan Textile Science Society, 1986 Annual Conference Research Presentation Proceedings). In the second method, a solvent-cast film is prepared by evaporating the solvent from a solution of ultra-high molecular weight polypropylene at a concentration of 1% or less, and then the film is sandwiched between polyethylene billets on both sides to create a simulated film. After solid-phase stretching in the melt state and further stretching it by about 6 times by passing it through a conical die, this solid-phase stretched film is subjected to normal tension stretching to obtain a highly stretched molded product with a stretching ratio of about 72 times. . This method uses a polyethylene biuret, so even if a fragile sample is used, it can be stretched at a high stretching rate without damaging or breaking the sample. Specifically, with this method, molecular weight Using 3.6 million ultra-high molecular weight polypropylene, an ultra-high molecular weight polypropylene stretched molded article having a tensile strength of 2.3 GPa has been obtained.

However, in this method, ultra-high molecular weight polypropylene is sandwiched in a billet and solid phase stretched using a conical die, which makes it difficult to manufacture fibers continuously, which reduces industrial productivity and costs. This is extremely disadvantageous in this respect. Further, the elongation at break of the ultra-high molecular weight polypropylene stretched molded article obtained by this method is extremely small.

That is, ultra-high molecular weight polypropylene fibers are generally produced by preparing a dilute solution of ultra-high molecular weight polypropylene and highly drawing gel fibers spun from this solution.

On the other hand, 100%
It is known that it is possible to obtain hard elastic fibers that recover their elasticity without undergoing plastic deformation even under close deformation (Textiles and Industry Vol. 1.30. No. 1,
P, 18-21.1970). In addition, it has been reported that hard elastic fibers with high elongation can be obtained by spinning polypropylene at high speed and heat-treating it (Fibers and Industries Vol. 1.3B, P, 51
~57.1980), *t: It has been reported that porous polypropylene fiber has an elongation rate of 40% and that this fiber is suitable as an energy absorbing fiber (Japanese Patent Application Laid-Open No. 63-249. Publication No. 711). However, the strength of this fiber is low.

All of these methods require heat treatment of the fibers at some stage after spinning, and because this heat treatment process is complicated, drawn fibers with high strength and high elongation at break cannot be produced industrially. It is disadvantageous as a production method.

Furthermore, there is a limit to the improvement of fiber elongation by such heat treatment, and it has been difficult to sufficiently increase the energy absorption of fibers using this ultra-high molecular weight polymer.

Purpose of the Invention The present invention aims to solve the problems associated with the prior art as described above, and is directed to a stretched ultra-high molecular weight polypropylene having high strength, high elongation at break, and excellent energy absorption properties. It is an object of the present invention to provide a method for manufacturing a molded body.

Summary of the Invention The method for producing an ultra-high molecular weight polypropylene stretched molded article according to the present invention comprises: (A) 50 to 99 parts by weight of ultra-high molecular weight polypropylene having an intrinsic viscosity [η] of 5 dN/g or more; and (B) the number of carbon atoms. 4
α-olefin polymers 1 to 18 having an intrinsic viscosity [η of 5 dll/g or more] derived from α-olefins 1 to 18
After adding a diluent and melt-mixing an ultra-high molecular weight polypropylene composition consisting of 50 parts by weight, this is extruded from a die and the resulting extrudate is stretched (stretching step).
It is characterized by

According to the production method of the present invention, it is possible to easily produce a stretched molded article containing a specific ultra-high molecular weight polypropylene and an α-olefin polymer in a specific ratio, and which has a particularly high elongation rate and a high energy absorption value. I can do it.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, a method for producing an ultra-high molecular weight polypropylene stretched molded article according to the present invention will be specifically explained.

The present inventors have discovered a method for producing a stretched molded article having an extremely high energy absorption value that has not been achieved with conventional ultra-high molecular weight polypropylene. That is, the method for producing a stretched molded body according to the present invention is a method for manufacturing a stretched molded body that has a high energy absorption amount by utilizing the orientation structure that ultra-high molecular weight polypropylene basically has. According to the present invention, the amount of energy absorption can be further improved by improving the elongation rate of the stretched molded product using a novel method.

In general, to improve the strength of molded objects such as fibers,
A method of stretching a molded body can be used.

However, as the stretching ratio increases, the molecules become highly oriented, so the elastic modulus improves, and as a result, the elongation rate decreases. When a fibrous molded body with such a reduced elongation rate is used as a rope, particularly as a mooring rope, a towing rope, or the like, it is likely to break when an excessive load is momentarily applied. Therefore, for use in such moving ropes, it is desirable to use a molded body with a low elastic modulus, that is, high strength, and high elongation.

However, since both elastic modulus and elongation are factors caused by the orientation of molecules, conventional methods change both in conjunction with each other, thus maintaining the elastic modulus at a constant level and decreasing it. It was difficult to improve the elongation rate without this.

The present invention proposes a method for suppressing molecular orientation and crystallization and improving elongation rate when drawing ultra-high molecular weight polypropylene fibers or films. It has been found that it is effective to use a composition containing a polymer. In other words, in order to obtain a drawn product with high tensile strength, the entanglement between molecules existing between the lamellae (crystals of undrawn yarn before drawing) and the lamellae must be minimized. It is necessary. Then, by using a resin composition in which ultra-high molecular weight polypropylene is blended with a specific α-olefin polymer, and by dispersing such resin in a diluent, the amount of entanglement and tie molecules in ultra-high molecular weight polypropylene can be reduced. By controlling this, a stretched molded article with high strength can be obtained.

Furthermore, since crystallization of the ultra-high molecular weight polypropylene is suppressed to some extent by the α-olefin polymer during stretching, it is thought that the elongation rate of the obtained molded article is improved.

Next, each component used in the manufacturing method of the present invention will be explained.

Ultra-high molecular weight polypropylene (A) The ultra-high molecular weight polypropylene used in the present invention has an intrinsic viscosity [η] measured at 135° C. in a decalin solvent of at least 5 dρ/g, preferably 10 dj
7/g or more. This intrinsic viscosity [η] is 5 dl/lr
Since the above ultra-high molecular weight polypropylene has a good molecular chain length, it is possible to produce a stretched molded article with excellent tensile strength. On the other hand, the upper limit of the intrinsic viscosity [η] is generally 30 dρ/g;
By using ultra-high molecular weight polypropylene having a molecular weight of less than /g, the concentration of doping agent does not become extremely high, so that melt fractures and the like do not occur and it is possible to efficiently produce a spinning body.

The ultra-high molecular weight polypropylene in the present invention includes a propylene homopolymer obtained by coordination anionic polymerization,
Alternatively, propylene and small amounts (e.g. 10 mol% or less) of other α-olefins, such as ethylene, l-butene, 4
A propylene copolymer containing methyl-1-pentene, 1-pentene, l-hexene, l-octene, i-decene, etc. is used.

In the production method of the present invention, the above-mentioned ultra-high molecular weight polypropylene is contained in the resin component in an amount of 50 to 99 parts by weight, preferably 6 parts by weight.
It is blended in an amount of 0 to 90 parts by weight.

α-olefin polymer (B) The α-olefin polymer (B) used in the present invention is:
The number of carbon atoms is 4 or more and has one or more ethylenic double bonds,
Preferred are polymers or copolymers obtained by polymerizing or copolymerizing α-olefins having 4 to 18 carbon atoms. Therefore, in the present invention, ethylene homopolymer and propylene homopolymer cannot be used as the α-olefin polymer.

Specifically, these α-olefins include polybutene-11poly-1-pentene, poly-1-hexene, poly-3-methyl-1-butene, poly-4-methyl-1-
pentene, poly-4-methyl-1,3-pentadiene,
Poly-5-methyl-1-hexene, poly-4-methyl-
Examples include 1-hexene, poly-4-phenyl-1-butene, poly-1-heptene, poly-1-octene, poly-1-nonene, and poly-1-decene.

Among these, polybutene-1, poly-1-pentene, poly-1-hexene, poly-3-methyl-1-butene, poly-4-methyl-1-pentene, poly-4-methyl-1,3 -Pentadiene, poly-5-methyl-1-hexene, poly-4-methyl-1-hexene, poly-4-
Phenyl-1-butene and the like are preferred.

Moreover, such an a-olefin polymer has an intrinsic viscosity [η] of 5 dn/g measured at 135°C in a decalin solvent.
or more, preferably 12.5 dll/g or more.

By using an α-olefin polymer with an intrinsic viscosity [η] of 5 dn/g or more, the stretched and oriented molded product swells and becomes sticky or dissolves when stretched in a solvent such as n-decane. There will be no fear.

On the other hand, although the upper limit of the intrinsic viscosity [η of the α-olefin polymer is not particularly limited, a polymer having an intrinsic viscosity [η] of 30 cNl/g or less is usually used, and by using such a copolymer, spinning stability can be improved. Improves sex.

The above-mentioned α-olefin polymers are usually thought to have a helical intracrystalline molecular structure, and by having such a structure, when drawing ultra-high molecular weight polypropylene, It is possible to effectively prevent ultra-high molecular weight polypropylene molecules from becoming tightly oriented and crystallizing. Therefore, it is possible to form an ultra-high molecular weight polypropylene molded article that has high strength, relatively low elastic modulus, and high elongation.

The α-olefin polymer in the present invention is an α-olefin homopolymer obtained by coordination anionic polymerization, or an a-olefin copolymer formed from two or more types of olefin monomers obtained by coordination anionic polymerization. , an α-olefin copolymer containing an α-olefin and a small amount of other monomers may be used.

In the production method of the present invention, the above α-olefin polymer is contained in the resin component in an amount of 1 to 50 parts by weight, preferably 10 parts by weight.
It is blended in an amount of ~40 parts by weight. In the present invention, the ultra-high molecular weight polypropylene and the α-olefin polymer are used within the above range so that the total amount of both is 100 parts by weight.

By blending the ultra-high molecular weight polypropylene and the α-olefin polymer in this way, it is possible to prevent the ultra-high molecular weight polypropylene from becoming oriented and crystallized by stretching, thereby preventing the increase in elastic modulus. It is possible to obtain a stretched molded product with a high ratio.

Diluent (C) The diluent (C) used in the present invention has a melting point of 10
An aliphatic hydrocarbon derivative having a temperature of 130° C. or higher and a boiling point of 130° C. or higher is used.

Among these, aliphatic hydrocarbon derivatives having a melting point of 20 to 120°C are particularly preferable, and more preferably 40 to 120°C.
Particular preference is given to aliphatic hydrocarbon derivatives in the range 00°C. Also, derivatives having a boiling point of 160°C or higher are preferred, and derivatives having a boiling point of 190°C or higher are particularly preferred.

Even if an aliphatic hydrocarbon derivative with a melting point of less than 10°C is used,
When using a screw extruder or the like, the compositions rotate together, making uniform melt mixing impossible.

Furthermore, if the boiling point is less than 130°C, the diluent will be evaporated and removed during spinning, making it impossible to spin smoothly.

The aliphatic hydrocarbon derivative used as the diluent is not particularly limited as long as it has the above-mentioned properties, but it is preferable to use a derivative having 8 or more carbon atoms, particularly 12 to 50 carbon atoms. In addition, the molecular weight of this derivative is
Usually, it is preferably in the range of 130 to 2000, particularly 200 to 800.

In addition, such aliphatic hydrocarbon derivatives have molecular terminals,
Alternatively, the main chain or side chain of the molecule may have a functional group.

Specific examples of such functional groups include carboxyl groups, hydroxyl groups, carbamoyl groups, ester groups, mercapto groups, and carbonyl groups.

Among these, functional groups such as carboxyl group, hydroxyl group, amino group, and ester group are preferred.

Examples of such aliphatic hydrocarbon derivatives include waxes, fatty acids, aliphatic alcohols, fatty acid amides, fatty acid esters, aliphatic mercaptans, aliphatic aldehydes, and aliphatic ketones.

Specifically, the so-called paraffin wax separated and purified from petroleum, medium-low polyethylene wax, which is a low molecular weight polymer obtained by copolymerizing ethylene or ethylene with other α-olefins, and ethylene copolymer wax. or waxes whose molecular weight has been lowered by thermally decomposing polyethylene such as low-medium-high-pressure polyethylene, and their wax oxides, or waxes such as modified waxes such as those modified with maleic acid; capric acid, lauric acid, myristic acid, Fatty acids such as valmitic acid, stearic acid, and oleic acid; Fatty alcohols such as lauryl alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol; Caprinamide, lauramide, and valmitinamide;
Fatty acid amides such as stearylamide; fatty acid esters such as stearyl acetate; and the like.

The aliphatic hydrocarbon derivative used in the present invention usually has one or more such functional groups, preferably 1 to 2 functional groups.
A compound having one, more preferably one, is used.

Such a diluent has excellent dispersibility in ultra-high molecular weight polypropylene and α-olefin polymers.

This dispersibility can be confirmed by observing the cross section of the undrawn yarn using a high-magnification scanning electron microscope. That is, the undrawn yarn is cut perpendicularly to the longitudinal direction with a sharp blade such as a microtome, and the undrawn yarn is immersed so that this cross section comes into contact with an extraction liquid such as hexane, heptane, or hot ethanol. After extracting and removing the diluent, the extracted cross section was examined using a scanning electron microscope at 3000°C.
When observed at a magnification of twice or more, almost no depression of 0.1 μm or more is observed in the undrawn yarn prepared using the above-mentioned diluent.

The amount of such diluent varies depending on the type of compound to be blended, but it is 1 part by weight per 100 parts by weight of the total weight of ultra-high molecular weight polypropylene and α-olefin polymer.
It is used in an amount of 5 to 1250 parts by weight, preferably 17.6 to 1150 parts by weight.

If the amount of diluent is less than the above range, the viscosity of the spinning dope will be too high, and the entanglement of the ultra-high polymer will be too large, making dispersion and spinning difficult, as well as making it difficult to obtain a spinning solution. The fibers become more prone to rough skin and stretch breakage. On the other hand, if the amount of the diluent is greater than the above range, the entanglement of the superpolymer will be too small, resulting in insufficient spinnability and fiber stretchability during spinning.

In addition, in the present invention, the above melting point is ^STM MA
3418, measured using a differential scanning calorimeter (DSC).

Production method [1] In the present invention, ultra-high molecular weight polypropylene and a specific α
- A spinning stock solution is prepared by mixing an olefinic polymer and a diluent according to a known method. The mixing of this ultra-high molecular weight polypropylene and α-olefin polymer with a diluent varies depending on the type of diluent used, but in general, mixing of the ultra-high molecular weight polypropylene and α-olefin polymer with a diluent is carried out using a screw extruder or the like.
at a temperature of 0 to 280°C, preferably 180 to 210°C,
More preferably, it is desirable to perform the mixing at a temperature of 190 to 200°C. If the mixing temperature is lower than the above temperature range, the ultra-high molecular weight polypropylene and α-olefin polymer will be difficult to disperse in the diluent, and the As a result, it becomes difficult to obtain a uniform unstretched body by spinning. On the other hand, if mixing is performed at a temperature higher than the above range, the molecular weight of the ultra-high molecular weight polypropylene may decrease, making it difficult to obtain a high-strength stretched molded product.

Such mixing can be carried out using a mixer equipped with heatable stirring blades, or can also be carried out using a single-screw or multi-screw extruder.

By using the composition thus prepared as a raw material for spinning, a spun body having high tensile strength and elongation can be produced.

In addition, when preparing the spinning stock solution as described above, it is desirable to mix a stabilizer in order to prevent thermal deterioration of the ultra-high molecular weight polypropylene and the α-olefin polymer. Stabilizers that can be used in this case include, for example, 3,5-di-tert-butyl-4-hydroxytoluene and tetrakis[methylene-3-(8
, 5-di-tert-butyl-4-hydroxyphenyl)propionate comethane, etc. can be used.

[Spinning] In the present invention, spinning is performed from the spinning dope obtained as described above by a melt extrusion method or the like.

Here, a filament for drawing is obtained by extruding the raw spinning wave from a spinneret of a die of a screw extruder, a film, sheet, or tape for drawing is obtained by extruding it from a flat die, and a circular - By extruding from a die, a pipe for forming a drawn hollow fiber is obtained.

In the present invention, a stretched molded article is obtained by extruding a spinning dope using a screw extruder or the like. The die temperature at this time is usually 140 to 300°C, particularly preferably 190 to 200°C, and by setting this temperature, filaments can be stably spun.

Although the filaments thus obtained can be drawn as they are, it is preferable to spin them while applying tension, that is, draft. For example, by spinning the melt extruded from a spinneret while applying tension, the drawability in the subsequent drawing step is improved.

The draft ratio at this time is usually 3 to 1000, particularly preferably 10 to 150.

Note that the draft ratio here represents the ratio between the inner diameter Do of the spinneret and the fiber diameter D1 obtained by cooling and solidifying the melt and winding it up.
It is defined by the following formula.

Draft ratio-D. /D1 The crystallization rate of the spinning stock solution extruded in this manner can be controlled by cooling with air cooling or forced cooling means such as a refrigerant such as water, methanol, ethanol, acetone, or the like.

[Stretching] In the present invention, the unstretched molded article obtained as described above is stretched.

Prior to stretching the unstretched molded body, the diluent contained in the unstretched molded body can be removed.

Alternatively, it can be stretched while being removed. and,
Stretching is usually carried out under heating.

The heating temperature in this case is generally 40 to 230"C, preferably 70 to 210"C, more preferably 90 to 170"C.
within the range of ℃.

As a heat medium for heating and maintaining the unstretched molded body at the above-mentioned temperature, ordinary heating means can be used in addition to air, steam, liquid medium, etc.

The diluent contained in the unstretched molded article can be removed, for example, by immersing the unstretched molded article in a solution that is compatible with the diluent and extracting it.

As the extraction solvent used here, it is preferable to use a medium that can extract the diluent contained in the unstretched molded body and also heat the unstretched molded body. Such a medium includes: It is preferable to use a solvent whose boiling point is higher than the stretching temperature, and specific examples of such solvents include decane, tetralin, decalin, kerosene, and the like.

In this case, by heating the extraction solvent, the same extraction solvent and heating medium can be used. However, the extraction solvent and the heating medium do not need to be the same; for example, after removing the diluent using an extractant that has the effect of removing the diluent, the unstretched compact may be heated in the heating medium. You can also do it.

The concentration of the diluent in the finally obtained stretched molded article is usually 10% by weight or less, preferably 1.5%.
It is removed in an amount of 0.5% by weight or less, more preferably 0.5% by weight or less.

The extent of the stretching treatment may be such that molecular orientation is imparted in at least one axial direction.

This stretching operation can be carried out either in one stage or in multiple stages of two or more stages. It is generally advantageous to carry out the above-mentioned stretching operation in a multi-stage stretching system of two or more stages, with the -th stage stretching being carried out at 60-120°C, preferably at 90-120°C.
Preferably, it is carried out at a relatively low temperature of 0.5°C. From the second stage onwards, the temperature is 120 to 230°C, preferably 135°C.
At a temperature of ~165°C, and 15~ higher than the stretching temperature in the previous stage.
It is desirable to stretch at stretching temperatures with a large temperature difference of 20° C. or more.

In addition, although stretching varies depending on the molecular orientation of the stretched molded product to be obtained and the heating temperature during stretching, it is generally
at least 10 times, preferably at least 10 times, more preferably at least 12 times
It is preferable to carry out the stretching operation at a magnification of 100 to 100 times.

Stretched molded product The stretched molded product obtained by the method of the present invention usually contains 50 to 99% by weight of ultra-high molecular weight polypropylene having an intrinsic viscosity [η] of 5 dρ/g or more and an intrinsic viscosity [η] of 5 dρ/g.
It consists of 1 to 50% by weight of an a-olefin polymer of 1/g or more and 10% by weight or less of a diluent.

Usually, the tensile modulus is 15 GPa or less, the breaking strength is 0.5 GPa or more, and the breaking elongation is 2.
0% or more, and the energy absorption value determined from the 50% breaking strength of the strength/elongation curve is 1 kg f m / g or more.

Effects of the Invention By the method for producing a stretched molded body according to the present invention, it is possible to obtain a stretched ultra-high molecular weight polypropylene molded body that has high strength, high elongation at break, excellent creep resistance, and excellent energy absorption value. can.

This stretched molded product is useful as an industrial textile material such as mooring ropes such as mooring lobes and towing ropes, high-strength multifilaments, strings, woven fabrics, and non-woven fabrics.

In addition, by using this stretched molded product as a reinforcing fiber for various resins such as epoxy resin and unsaturated polyester, and synthetic rubber, this fiber has high strength and low density, so it can be used as a reinforcing fiber for various resins such as epoxy resin and unsaturated polyester. fiber,
Compared to molded articles using boron fibers or aromatic polyamide fibers, the weight can be particularly reduced.

Also, like glass fiber, UD (Unit Dir)
ction) Laminated board, SMC (5heet Mo
lding Compound), BMC(Bul
It can be used for molding processes such as k Molding Compound), and can be used for lightweight materials such as automobile parts, boat and yacht structures, electronic circuit boards, and acoustic materials.
It is expected to be used in various composite materials in the high-strength field.

Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these examples in any way as long as they do not go beyond the gist of the invention.

Example 1 90 g of ultra-high molecular weight polypropylene powder with an intrinsic viscosity [η] of 14.6 d1/Ir and 90 g of ultra-high molecular weight polypropylene powder with an intrinsic viscosity [η] of 17.
odl/g ultra high molecular weight polyester-1 powder 10g
and paraffin wax (melting point -69℃, molecular weight -46
0) using a 20 mmφ L, /D-20 screw extruder at a resin temperature of 200° C. to prepare an ultra-high molecular weight polypropylene resin composition.

At this time, 3,5-tert is used as a process stabilizer.
Butyl-4-hydroxytoluene and tetrakis [
Methylene-3 (3,5-di-tert-butyl-4-hydroxyphenyl) propionate comethane was added in an amount of 0.1% by weight based on the total of ultra-high molecular weight polypropylene and ultra-high molecular weight polybutene-1.

Spinning Using the ultra-high molecular weight polypropylene composition prepared as described above as a spinning dope, the melt was spun under the following conditions to obtain fibers.

That is, the spinning dope was extruded at a resin temperature of 190° C. using a plunger type extruder equipped with a spinning nozzle of 2III1φ.

This extruded melt was wound around a bobbin at a draft ratio of 30 in air at 25° C. under an air gap of about 70 ann to form a yarn.

Stretching The fiber (original thread) prepared as described above was continuously stretched using 5 godet rolls and 4 stretching tanks (tank length 50 cm).

That is, the rotation speed of the first godet roll is set to 25 cm/
minute, the rotational speed of the second godet roll is 187.5 (7
) At 7 minutes, the rotation speed of the third godet roll was increased to 243.8.
The rotational speed of the fourth godet roll was set to 292.cm/min.
The rotation speed of the fifth godet roll was set to 350 cm/min.
cm/min, and the total stretching ratio was 14 times by four-stage stretching.

In addition, in the drawing tank between the first and second Godet rolls, 10
n-decane at 0°C, n-decane at 120°C in the drawing tank between the second and third godets and sotrols, and flusol P (at 140°C) in the drawing tank between the third and fourth godetrolls.
Thermal chemical industry type heating medium) is used as the heating medium, and the fourth
Flusol P at 160° C. was used as a heating medium in the drawing tank between the and the fifth Gode and Sotrol.

Moreover, the effective length of each drawing tank is 50 (7).

Here, the total stretching ratio is determined by the rotational speed ratio of the fifth godet roll and the first godet roll.

Table 1 shows the tensile modulus, strength at break, elongation at break, and energy absorption value at 50% strength at break of the obtained stretched molded product.
Shown below.

In addition, the tensile modulus, elongation at break, and strength at break of the obtained stretched molded body were measured using Autograph DO8- manufactured by Shimadzu Corporation.
Measurement was performed at room temperature (25°C) using a 50M model. The measurement conditions were a sample length of 25 mm between the clamps, and a bowing speed of 2511 I.
The chart speed was set at 2SC1ar&/min.

However, the tensile modulus is calculated using stress at 2% strain, and the fiber cross-sectional area required for calculation is
．． It was calculated from the weight of the sample and the weight of the sample.

In addition, the energy absorption value at 50% strength was calculated from the area of the strength and elongation curve.

In the Examples and Comparative Examples described below, the tensile modulus, strength at break, elongation at break, and energy absorption value at 50% strength were measured as described above.

Example 2 In Example 1, as ultra-high molecular weight polypropylene,
80 g of ultra-high molecular weight polypropylene powder with an intrinsic viscosity [η] of 14.6 dfl/g was used, and as an α-olefin polymer, the intrinsic viscosity [η] was 17. An ultra-high molecular weight polypropylene resin composition was prepared in the same manner as in Example 1, except that 20 tr of ultra-high molecular weight polybutene-1 powder of Odρ/g was used.

Using this composition as a stock solution, a spun body and a stretched molded body were produced in the same manner as in Example 1. The total stretching ratio of the obtained stretched molded product was 13 times.

Table 1 shows the properties of the obtained stretched molded product.

Example 3 In Example 1, as ultra-high molecular weight polypropylene,
50 g of ultra-high molecular weight polypropylene powder with an intrinsic viscosity [η] of 14.6 dll/g was used, and as an α-olefin polymer, the intrinsic viscosity [η] was 17. 0 dl/
An ultra-high molecular weight polypropylene resin composition was prepared in the same manner as in Example 1, except that 50 g of ultra-high molecular weight polybutene-1 powder was used.

Using this composition as a stock solution, a spun body and a stretched molded body were produced in the same manner as in Example 1. The total stretching ratio of the obtained stretched molded product was 12 times.

Table 1 shows the properties of the obtained stretched molded product.

Example 4 In Example 1, as ultra-high molecular weight polypropylene,
Intrinsic viscosity [η] is 17. 5d (using 80 g of ultra-high molecular weight polypropylene powder of 1/g, using 20 g of ultra-high molecular weight polybutene-1 powder having an intrinsic viscosity [η] of 12.Odρ/g as the α-olefin polymer, An ultra-high molecular weight polypropylene resin composition was prepared in the same manner as in Example 1 except that the resin temperature was 200°C.

Using this composition as a stock solution, a spun body and a stretched molded body were produced in the same manner as in Example 1. The total stretching ratio of the obtained stretched molded product was 12.5 times.

Table 1 shows the properties of the obtained stretched molded product.

Example 5 In Example 1, as ultra-high molecular weight polypropylene,
Intrinsic viscosity [η] is 17.5d11. Using 65 g of ultra-high molecular weight polypropylene powder of An ultra-high molecular weight polypropylene resin composition was prepared in the same manner as in Example 1 except that

Using this composition as a stock solution, a spun body and a stretched molded body were produced in the same manner as in Example 1. The total stretching ratio of the obtained stretched molded product was 12.5 times.

Table 1 shows the properties of the obtained stretched molded product.

Example 6 In Example 1, as ultra-high molecular weight polypropylene,
90 g of ultra-high molecular weight polypropylene powder with an intrinsic viscosity [η] of 17.5 dll/g was used as an α-olefin polymer. An ultra-high molecular weight polypropylene resin composition was prepared in the same manner as in Example 1 except that 10 g of powder was used and the resin temperature was 200°C.

Using this composition as a stock solution, a spun body and a stretched molded body were produced in the same manner as in Example 1. The total stretching ratio of the obtained stretched molded product was 16 times.

Table 1 shows the properties of the obtained stretched molded product.

Comparative Example 1 In Example 1, as ultra-high molecular weight polypropylene,
Using 80 g of ultra-high molecular weight polypropylene powder with an intrinsic viscosity [η] of 14.6 dL/g, ultra-high molecular weight polybutene-1 with an intrinsic viscosity [η] of 4.8 dD/g was used as an α-olefin polymer. Use 20g of powder and set the resin temperature to 2.
A resin composition was prepared in the same manner as in Example 1 except that the temperature was 00°C.

After spinning using this resin composition in the same manner as in Example 1, an attempt was made to stretch it in n-decane at 90°C, but the filament dissolved and stretching could not be carried out.

Comparative Example 2 In Example 1, as ultra-high molecular weight polypropylene,
The procedure was the same as in Example 1, except that 100 g of ultra-high molecular weight polypropylene powder with an intrinsic viscosity [η] of 14.66 D/g was used, the α-olefin polymer was not used, and the resin temperature was 200°C. A resin composition was prepared.

Using this composition as a stock solution, a spun body and a stretched molded body were produced in the same manner as in Example 1. The total stretching ratio of the obtained fiber was 12 times.

Table 1 shows the properties of the obtained stretched molded product.

Comparative Example 3 In Example 1, as ultra-high molecular weight polypropylene,
Same as Example 1 except that 100 g of ultra-high molecular weight polypropylene powder with an intrinsic viscosity [η of 1/g was used, no a-olefin polymer was used, and the resin temperature was 200°C. A resin composition was prepared in the same manner.

Using this composition as a stock solution, a spun body and a stretched molded body were produced in the same manner as in Example 1. The total stretching ratio of the obtained stretched molded product was 15 times.

Table 1 shows the properties of the obtained stretched molded product.

Comparative Example 4 In Example 1, as ultra-high molecular weight polypropylene,
Using 80 g of ultra-high molecular weight polypropylene powder with an intrinsic viscosity [η] of 17.6 dρ/g, using 20 g of ethylene-propylene copolymer (Mooney viscosity -80) instead of the α-olefin polymer, A resin composition was prepared in the same manner as in Example 1 except that the resin temperature was 200°C.

Using this composition as a stock solution, a spun body and a stretched molded body were produced in the same manner as in Example 1. The total stretching ratio of the obtained stretched molded product was 12.5 times.

Table 1 shows the properties of the obtained stretched molded product.

69-

Claims (1)

[Claims] 1) 50 to 99 parts by weight of ultra-high molecular weight polypropylene having an intrinsic viscosity [η] of 5 dl/g or more and an α-olefin having an intrinsic viscosity [η] of 5 dl derived from an α-olefin having 4 to 18 carbon atoms.
After adding a diluent and melt-mixing an ultra-high molecular weight polypropylene composition consisting of 1 to 50 parts by weight of an α-olefin polymer having a molecular weight of 1 to 50 parts by weight or more, this is extruded through a die, and the resulting extrudate is A method for producing an ultra-high molecular weight polypropylene stretched molded article, which comprises stretching.