JPH03178418A - Polyethylene formed body and manufacture of oriented formed body - Google Patents

Abstract

PURPOSE:To obtain a formed body, which has high elastic modulus and high strength and almost no lowering of the tensile strength of which occurs even when corona discharge treatment is applied, by a method wherein melt mixture consisting of polyethylene having the specified intrinsic viscosity and diluent is extruded through a die nozzle by being given the specified shear rate and shear stress so as to in-die orient the polyethylene in order to realize the specified degree of orientation in the formed body. CONSTITUTION:The normal content of polyethylene in mixture can be enhanced to 20 wt.% or more, when the polyethylene, the intrinsic viscosity of which is 3.0 dl/g or more, is used. Diluent, the melting point of which is 25 deg.C or higher, is preferably used. By extruding the melt mixture of the polyethylene and the diluent through a die nozzle under the condition that the shear rate of 20 sec<-1> and the shear stress of 1 X 10<5> - 8 X 10<5> dyn/cm<2> are given to the melt mix ture, at least some part of the polyethylene in the melt mixture is oriented in a die. By extrudng the melt mixture under the above-mentioned conditions, a formed body having the degree of orientation F of 0.7 or more is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing a polyethylene molded article and a stretched molded article thereof. More specifically, the present invention relates to a method for producing a polyethylene molded product and a stretched polyethylene molded product that have excellent strength and have almost no decrease in tensile strength even when subjected to corona discharge treatment.

As well as its polyethylene molecular weight commonly used,
There are polyethylene (general purpose polyethylene) of about ooo~200,000, low molecular weight polyethylene (so-called wax), high molecular weight polyethylene, and ultra-high molecular weight polyethylene.

Among such polyethylenes, ultra-high molecular weight polyethylene generally has a molecular weight of 1.000.000 or more, and has completely different characteristics from general-purpose polyethylene. That is, this ultra-high molecular weight polyethylene 1
It has extremely excellent properties such as impact resistance, abrasion resistance, chemical resistance, and tensile strength, and new uses as engineering plastics are being developed by taking advantage of these properties.

Although ultra-high molecular weight polyethylene (还) has the above-mentioned excellent properties, its high molecular weight makes its intrinsic viscosity extremely high. Therefore, this ultra-high molecular weight polyethylene has extremely low fluidity and When manufacturing polyethylene molded bodies, extrusion molding and injection molding methods, which have been conventionally used in the manufacture of molded bodies using general-purpose polyethylene, are rarely employed.

When manufacturing a molded article using such ultra-high molecular weight polyethylene, a mixture of +4 in which a small amount of ultra-high molecular weight polyethylene is added to a diluent is prepared in advance, and this mixture is used to form a molded article of a desired shape. A method is adopted in which the diluent is removed after preparation.

For example, JP-A No. 58-81612 states that an ethylene polymer or copolymer having a weight average molecular weight of 400,000 or more and a ratio of weight average molecular weight to number average molecular weight Mw/Mn of less than 5 is 20% by weight or less. A method for producing filaments having a tensile strength of 1.5 Gpa or more using a solution containing a solvent in an amount of at least 80% by weight is disclosed.

However, due to the high molecular weight of polyethylene in the polyethylene solution used in this method, the upper limit of the polyethylene concentration disclosed is 20% by weight.

Specifically, for example l? Even when polyethylene with a relatively low molecular weight, such as a weight average molecular weight of 500,000, is used, a solution with a polyethylene concentration as low as 8% by weight is used.

Even if such a solution is used, the tensile strength of the filament obtained is 1.9 Gpa (Mw/Mn =
2.9). In order to produce filaments with a tensile strength of 2 Gpa or more using this method, it is necessary to use polyethylene with a very high molecular weight of about 1.1 million, and the solution when using such polyethylene is is a solution with a polyethylene concentration of only about 2% by weight.

Additionally, JP-A No. 167010/1983 states that a solution is prepared by mixing polyethylene with a weight average molecular weight of 200,000 to 4,000,000 and a diluent, and by using this solution, it is possible to obtain a strength of at least 13 g/denier and a strength of 350 g. A method of manufacturing a polyethylene molded body having a modulus of /denier is disclosed. This method is basically the same as the technique disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 58-81612, and the concentration of the polyethylene solution actually used is only about 10% by weight.

In this way, when producing molded bodies from ultra-high molecular weight polyethylene, a large amount of diluent must be used, making it difficult to significantly improve the work efficiency when producing molded bodies.

Polyethylene with a molecular weight of about 200.000 to 1.000.000 has better moldability compared to ultra-high molecular weight polyethylene, but it has properties closer to general-purpose polyethylene. Therefore, using polyethylene with such a molecular weight, it is possible to obtain a molded article with extremely excellent properties such as impact resistance, abrasion resistance, chemical resistance, and tensile strength, like filaments formed from ultra-high molecular weight polyethylene. In addition, oriented polymer polyethylene molecules are sometimes used as fibers for reinforcing composite materials. desired. However, since car polyethylene generally does not have very good adhesive properties, methods have been adopted to improve its adhesive properties, and one method is to
Corona discharge treatment is known.

I is a conventionally known high molecular weight polyethylene molecular oriented material.
L The force that improves adhesion when subjected to corona discharge treatmentC
1. The tensile strength may be significantly reduced. 4. The present invention (4) aims to solve the problems in the conventional technology as described above, and has It is an object of the present invention to provide a method for producing a polyethylene molded article and a polyethylene stretched molded article whose bow tensile strength hardly decreases even when subjected to corona discharge treatment.

and 丑dandan 1 The method for producing a polyethylene molded article according to the present invention involves heating a molten mixture of polyethylene having an intrinsic viscosity of 3.0 dl/g or more and a diluent at a shear rate of 20 sec-1 or more,
Kak IX 1×105 ~8X 1×105 dyn/
The polyethylene was extruded from the die nozzle while being oriented in the die while applying a shear stress of cm2, so that the degree of orientation was 0.
．． It is characterized by producing a polyethylene molded product of 7 or more.

Flat core The method for producing a polyethylene stretched molded body according to the present invention is to process a molten mixture consisting of polyethylene having an intrinsic viscosity of 3.0 dl/g or more and a diluent at a shear rate of 20 sec-1 or more and at a shear rate of 1×10 5 to 8× 1×105
While applying a shear stress of dyn/cm2, the polyethylene is extruded through the die nozzle while being oriented in the die, and a polyethylene molded body with an orientation degree of 0.7 or more is ice-cold.
The method is characterized in that the polyethylene molded body is then stretched three times or more.

In the method of the present invention, polyethylene is extruded by controlling the extrusion molding conditions, so when the polyethylene is extruded, it is oriented to a certain extent in the die.For this reason, the degree of orientation that was conventionally difficult to obtain is achieved. It has become possible to produce polyethylene molded bodies with high
The stretched molded product obtained by stretching such a molded product has almost the same elastic modulus and strength as the stretched molded product of ultra-high molecular weight polyethylene, even if the molecular weight of the raw material polyethylene is 1 million or less. .

By adjusting the extrusion conditions as described above, it is possible to produce molded products and stretched molded products with excellent properties, especially using polyethylene. polyethylene,
In particular, even among ultra-high molecular weight polyethylenes, those having a relatively low molecular weight can be applied.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for producing a polyethylene molded article according to the present invention and a method for producing a stretched molded article using a molded article obtained by this method will be specifically explained.

The present inventor conducted research on a method for easily manufacturing a molded article with excellent properties formed from ultra-high molecular weight polyethylene, and found that even polyethylene with a lower molecular weight than ultra-high molecular weight polyethylene can be used at a certain shear rate. We found that polyethylene can be oriented in the die by extrusion molding and adjusting the shear stress applied to the polyethylene during extrusion molding, and using a diluent with a low melting point in this orientation state IL. By doing so, it is well maintained even in the molded product. Therefore, by stretching such a molded body, high elastic modulus and
The present invention was completed after discovering that a high-strength polyethylene stretched molded product could be manufactured.
The polyethylene has an intrinsic viscosity [η] of 3.0 dl/g or more measured at 35°C. Therefore, in the present invention, so-called high molecular weight polyethylene or ultra-high molecular weight polyethylene can be used. The method IL of the present invention is particularly useful when polyethylene having an intrinsic viscosity within the range of 3.5 to 10 dl/g is used.

The polyethylene used in the present invention may be a homopolymer of ethylene or a copolymer of ethylene and a small amount of a-olefin.

When using such a copolymer of ethylene and a small amount of a-olefin, the ethylene content is usually 95%.
A copolymer of mol % or more, preferably 98 mol % or more, is used.

1 as the a-olefin forming such a copolymer.
4 Usually an a-olefin having 3 to 10 carbon atoms is used. Specific examples of such a-olefins include propylene, 3-methyl-1-butene, 4-methyl-1-pentene, 1-butene, 1-pentene, 1
-hexene, 1-heptene, 1-octene and the like.

In addition to the above-mentioned σ-olefin, other polymerizable components such as cyclic olefins may be copolymerized within a range that does not impair the properties of the polyethylene used in the present invention.

In the present invention, polyethylene as described above is melt-mixed with a diluent. As the diluent used here 1
Although it is possible to use a substance that is liquid at room temperature, it is preferable to use a substance with a melting point of 25°C or higher. That is, by using a substance that is solid at room temperature (25' C), the diluent begins to solidify immediately after being extruded from the Gouy nozzle, making it difficult for the oriented state of the polyethylene oriented within the Gouy to collapse, and the obtained Inside polyethylene molding! ,
Since the molecular orientation is likely to remain as a history, a polyethylene body having a good degree of orientation F can be obtained.

As such a diluent, an aliphatic hydrocarbon compound that is solid at room temperature or an aliphatic hydrocarbon compound derivative that is solid at room temperature is preferably used.

Here, as the aliphatic hydrocarbon compound, lj is usually a compound having a molecular weight of 2000 or less, preferably 1000 or less, more preferably 800 or less. Specifically 1
N-alkanes with 22 or more carbon atoms, such as inverted tocosane, tricosane, tetracosane, and triacontane, or mixtures of these with lower and in-alkanes as main components, paraffin wax separated and refined from petroleum, ethylene, or ethylene and other Low molecular weight polymers obtained by copolymerizing with a-olefin, such as medium/low pressure polyethylene wax, high pressure polyethylene wax, ethylene copolymer wax, medium/low pressure polyethylene, high pressure polyethylene, etc., are heat reduced. Examples include waxes whose molecular weight has been lowered by, for example,

Such aliphatic hydrocarbon wax iL may be used after being subjected to oxidation treatment or modification with maleic acid, if necessary.

Further, as a diluent other than an aliphatic hydrocarbon compound, a derivative of an aliphatic hydrocarbon compound is used.

Such compounds include (for example, one or more carboxyl groups, preferably one to two, particularly preferably one carboxyl group, hydroxyl group, carbamoyl group) at the end or inside of an aliphatic hydrocarbon group (alkyl group, alkenyl group).
Ester group Examples include compounds having a functional group such as a mercaptopentacarbonyl group. The aliphatic hydrocarbon compound derivatives include IL, the above compounds having 8 or more carbon atoms, preferably 12 to 50 carbon atoms, and fatty acids, aliphatic alcohols, and fatty acid amides having a molecular weight of 130 to 20 liters, preferably 200 to 800. , fatty acid esters, aliphatic mercaptans, aliphatic aldehydes, and aliphatic ketones.

These specific compounds include tun fatty acids such as capric acid, lauric acid, myristic acid, valmitic acid, stearic acid, and oleic acid. Fatty alcohols include lauryl alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol; fatty acid amides include capric acid, Amide, lauramide, valmitinamide, stearylamide; Examples of the fatty acid ester include stearyl acetate.

The polyethylene and diluent as described above are mixed in a molten state. The mixing temperature at this time (varies depending on the type of polyethylene and diluent used, but usually 160~
The temperature is 250°C.

In the present invention, when polyethylene with an intrinsic viscosity of 3.0 dl/g or more is used, the content of polyethylene in the mixture is usually 20% by weight or more, preferably 25% by weight or more, and more preferably 30% by weight or more. It can be done. By using such a highly concentrated mixture, the oriented state of the polyethylene oriented within the goo is maintained within the molded body.

In addition, 14
Furthermore, components such as anti-oxidation valve L lubricant can also be blended.

The molten mixture of polyethylene and diluent thus prepared is extruded through a die nozzle at a specified shear rate and while applying a specified shear stress.

By using such a highly concentrated mixture and extruding the molten mixture through a die nozzle under specific extrusion conditions, at least a portion of the polyethylene in the molten mixture is oriented within the IL die.

In the present invention, when extruding the molten mixture from the die nozzle, the shear rate is 1:3, 20 seconds or more, preferably 25 seconds or less, particularly preferably 30 seconds.
It is more than c-i. Upper limit value of shear rate (9) Force that does not need to be particularly limited from the perspective of orientation of the molded body\If the shear rate becomes too high, melt fracture is likely to occur, so the upper limit is usually set to prevent melt fracture. This upper limit value is usually 200 se
c-1, preferably 150 sec-'.

When performing extrusion molding at the shear rate mentioned above,
The shear stress experienced by the melt in the nozzle is LX105~8
×105 dyn/cm2, preferably 1.5X1×
105~8x 10! dyn/cm2, more preferably 2×10S to 8X 1×105 dyn/cm
It is set within the range of 2.

If the shear stress is smaller than the above range, effective orientation within the die cannot be given to the polyethylene, and if it exceeds the upper limit, the orientation state of the molded product cannot be improved due to turbulent flow such as melt fracture.

The values of such shear rate and shear stress depend on the mixing ratio of polyethylene and diluent as described above, and are also influenced by the melt extrusion temperature. Therefore, the extrusion temperature (9) should be set so that the shear rate and shear stress are within the above range, taking into consideration the mixing ratio of polyethylene and diluent. Set within range.

Here, in the present invention, when it is assumed that the molten mixture forms a laminar flow and is extruded according to the shape of the die nozzle when the molten material is discharged into the atmosphere,
; means the velocity of the molten mixture at the die nozzle wall relative to the nozzle. Further, "shear stress ° and ↓L" can be determined based on a flow curve under specific conditions, which is predetermined based on the above shear rate.

Melt molding is generally performed using a melt extrusion molding machine. By melt extrusion through a spinneret (nozzle), a filament for drawing is obtained; by extrusion through a flat die or a ring die, a drawing film, sheet or tape is obtained; and by further extrusion through a circular die. By this, a pipe (parison) for stretch blow molding is obtained.

By carrying out extrusion molding under the above conditions, a molded article having an orientation degree F of 0.7 or more can be obtained.

Furthermore, by setting suitable conditions, the degree of orientation F can be reduced to 0.
It is possible to obtain a molded article having a molecular weight of 8 or more, more preferably 0.90 or more.

The degree of orientation F1 of the molded article, that is, the degree of molecular orientation, can be measured by X-ray diffraction.

In the present invention, in the case of polyethylene drawing filaments, the degree of orientation F (transition) is calculated by the half-width method described in detail in Yukichi Go and Teru Kubo, Kogyo Kagaku Zasshi, Vol. 39, p. 992 (1939). This is a value calculated according to the degree of orientation, that is, the half-width (°) of the intensity distribution curve formed along the Debye ring in the plane of Equation 1.

The polyethylene molded article produced by the method according to the present invention is highly oriented even though no stretching operation is actively performed.

Sara & Pi This molded object is an example! The degree of orientation is further increased by subjecting the undrawn filament to a drafting operation.

The draft ratio in the case of draft operation (depending on the temperature of the inversion mixture, the molecular weight of the polyethylene, the composition ratio with the diluent, etc.) is usually 3 or more, preferably 6 or more.

However, the degree of orientation of the molded product is improved by the drafting operation in this way.
If the extrusion conditions at the nozzle deviate from the above ranges of shear rate and shear stress, good results will not be obtained in the subsequent stretching operation even if the draft operation is performed.

Here, the draft ratio +4 can be obtained by measuring the extrusion speed V @ of the melt in the die nozzle and the winding speed ■ of the undrawn material cooled and solidified, and substituting these values into the following equation. can.

Draft ratio = v/V @ The polyethylene molded product thus obtained i4 After removing the diluent contained in the molded product using the method described later, the molded product can be used as it is.C1 Further stretching. This further improves properties such as elastic modulus and strength.

The polyethylene stretched molded article of the present invention having an intrinsic viscosity of 3.0 dl/g or more can be produced by stretching a polyethylene molded article obtained by the method described above. That is, by stretching the polyethylene molded product in at least one axis, the degree of molecular orientation in the molded product is further improved.

Such stretching treatment (rolling) is generally carried out by heating and holding the material to be stretched at a temperature of 40 to 160°C, preferably 80 to 145°C. It is also possible to use an organic solvent. Among these heating media, it is preferable to use an organic solvent. By using such an organic solvent, the above-mentioned diluent can be eluted and removed. The organic solvent preferably has a boiling point higher than the melting point of the molded article. Specific examples of such organic solvents include aliphatic hydrocarbons such as l&decalin, decane, and kerosene. By carrying out the stretching operation using a heating medium such as the above, it is possible to uniformly remove the diluent described above, and the occurrence of stretching unevenness during stretching is reduced.Therefore, stretching at a higher stretching ratio is possible. operations can be performed.

Note that the diluent can be removed during stretching as described above, but the diluent can be removed by immersing the unstretched material in a solvent such as hexane, heptane, hot ethanol, chloroform, or benzene before the stretching operation. Alternatively, after the stretching operation, the obtained stretched product may be immersed in a solvent such as hexane, heptane, hot ethanol, chloroform, or benzene. Furthermore, these methods can also be used in combination.

In the present invention, stretching operation 1'! , -stage or multiple stages of two or more stages. Stretching ratio! 9. 75C1, which depends on the degree of molecular orientation and the degree of increase in melting temperature associated therewith, can be generally set within a range of 5 to 80 times, preferably 10 to 50 times. Note that this stretching ratio is an area stretching ratio.

In the present invention, it is preferable to carry out the stretching operation in two or more stages including one turn stretching operation + L. In this case, the stretching operation in the -th stage is performed at a relatively low temperature of 80 to 120°C to remove the diluent in the extruded body. It is preferable that the stretching operations in the second and subsequent stages be carried out at a temperature of 120 to 160° C., moreover at a temperature higher than the stretching temperature in the -th stage.

In the above-mentioned stretching operations (9) For example, in the case of uniaxial stretching operations performed on filaments, tapes, etc. (9) Tensile stretching can be performed between rollers with different circumferential speeds; In the case of biaxial stretching operation, it is sufficient to carry out tensile stretching in the longitudinal direction between rollers with different circumferential speeds in one rotation, and also to perform tensile stretching in the transverse direction using a tender etc. after stretching. Biaxial stretching is also possible.

In the case of a three-dimensional molded product such as a container, a biaxially stretched molded product can be obtained by a combination of axial stretching and expansion stretching in the circumferential direction.

The oriented stretched molded product thus obtained may be subjected to heat treatment (heat setting treatment) while being fixed, if necessary. This heat treatment is generally carried out at a temperature of 140-180°C, preferably 150-175°C, for 1-20 minutes, preferably 3-10 minutes. By subjecting the stretched molded body to the heat treatment as described above, crystallization of the oriented stretched molded body further advances and the crystal melting temperature shifts to a higher temperature side, thereby improving the strength and elastic modulus of the molded body.

As mentioned above, in the method for producing a polyethylene stretched molded body according to the present invention, molecular orientation is imparted to the polyethylene molded body in a die during production, and the molded body is further stretched, thereby achieving a tensile strength of 2 GPa or more. and 5
A polyethylene stretched molded body having an elastic modulus of 0 GPa or more is obtained. However, with the manufacturing method of the present invention, it is possible to produce a polyethylene stretched molded product having the same elastic modulus and strength as those using ultra-high molecular weight polyethylene, without using polyethylene with a high molecular weight such as ultra-high molecular weight polyethylene. Obtainable.

The degree of orientation of the polyethylene stretched molded product thus obtained is 0.95 or more, preferably 0.96 or more, and more preferably 0.97 or more.

In the present invention, the reason why molecular orientation is imparted to the molded product obtained by extruding a molten mixture of polyethylene having an intrinsic viscosity of 3.0 dl/g or more and a diluent at a specific shear rate and shear stress. The present inventor (9) believes that this is due to the following reasons.

It is known that molecular orientation usually occurs when molecules flow through a die nozzle, but in the case of relatively low molecular weight polymers, even if they are oriented once, the relaxation rate of molecular orientation is slow. Because of this, the orientation state is relaxed along with the swell phenomenon the moment the die nozzle is pushed out into the atmosphere, and the orientation of the molecules imparted within the die nozzle is unlikely to remain in the molded body as history.

However, in the case of high molecular weight polymers, if a shear stress above a certain value is applied in the presence of a diluent in the die nozzle,
The molecules are stretched in the direction of flow. In order to elongate molecules by conventional stretching or drafting operations, it is necessary that the molecular chains are intertwined to some extent. Tokoro Kerr Such molecular entanglement 14 After molecular elongation, the elongated chains become structural defects when crystallized.

Therefore, it is not considered to be a preferable method for relatively low-molecular polymers that require a lot of molecular entanglement.On the other hand, by applying shear stress, it is possible to
The L molecules become fully extended, and the degree of orientation of the molecules improves. Therefore, it is possible to maintain this state even after molding.111
Improves properties such as elastic modulus and strength of stretched products.
It is thought that even when polyethylene with a relatively low molecular weight is used, it will have properties comparable to molded articles made of ultra-high molecular weight polyethylene.

Tokoro car JP-A-58-81 exemplified as prior art
612 and JP-A No. 61-167010. Because the concentration of polyethylene is low, orientation in the die nozzle is difficult to occur. Because the solvent used is a good solvent for polyethylene, it takes a considerable amount of time to crystallize. During this time, the state of molecular orientation is relaxed, and the history of molecular orientation within the die cannot be carried into the molded product. Furthermore, since the solvent is a liquid, it does not have the ability to prevent relaxation of the orientation state of molecules. For these reasons, it is considered that the orientation within the die nozzle cannot be used effectively.

However, in the present invention, polyethylene with a somewhat high molecular weight is extruded under specific conditions.
The orientation of the polyethylene in the die nozzle does not deteriorate that much, and by using a diluent that is solid at room temperature, the diluent solidifies in a relatively short time when the melt is released into the atmosphere from the die nozzle. By doing so,
The orientation state of molecules becomes difficult to collapse.

Therefore, by stretching such a molded body,
Furthermore, the degree of molecular orientation has been improved, and even when using polyethylene with a lower molecular weight than ultra-high molecular weight polyethylene, it is possible to produce a stretched molded product with elastic modulus and tensile strength comparable to ultra-high molecular weight polyolefin. can.

Therefore, by adopting the method of the present invention, polyethylene molded products and stretched molded products produced by the method of the present invention can be used in applications where ultra-high molecular weight polyolefin molded products or stretched molded products have conventionally been used. You will be able to do this.

Furthermore, the polyethylene molded product and polyethylene stretched molded product obtained according to the present invention have the characteristics that when subjected to corona discharge treatment, the adhesion is greatly improved by 75<, and the tensile strength is hardly decreased.

In the present invention, a molten mixture consisting of a specific polyethylene and a diluent is melt-extruded at a specific shear rate and shear stress to form a molten mixture oriented in a gooey. The orientation state of polyethylene is maintained even in the molded article.

Therefore, by employing the method of the present invention, a polyethylene molded article with a high degree of orientation can be obtained. By stretching the molded product thus obtained, a polyethylene stretched molded product which has high elastic modulus and high strength and whose tensile strength hardly decreases even when subjected to corona discharge treatment can be obtained.

[Examples] The present invention will be explained below with reference to Examples.The present invention is not limited to these Examples.

Intrinsic viscosity measured in decalin at 135℃ is 5.6d1
/g of ethylene-propylene copolymer (ethylene content: 99.9%) and paraffin wax (melting point: 69°C, molecular weight: 490) in a weight ratio of 30 to 0 was melt-spun under the following conditions. That is, 3,5-dimethyl-tert-butyl- is added to the mixture as a process stabilizer.
0.1 part by weight of 4-hydroxytoluene was blended with 100 parts by weight of the above ethylene-propylene copolymer, and the mixture was then melt mixed using a screw extruder at a set temperature of 190°C. The melt is passed through a spinning gui with an orifice diameter of 2 mm attached to the extruder.
Shearing rate 25sec-1, shearing stress 2.6X 1x10
5 dyn/cm 2, melt spun at a temperature of 180°C, and the spun fibers were taken up with a draft ratio of 33 times in an air gap of 180 cm, and cold ridged in the air.
The degree of orientation F of this undrawn fiber is 0.9, and the undrawn fiber is further drawn under the following conditions to obtain an oriented fiber. using 3
N-decane was used as the heating medium in the first and second drawing tanks, and the temperature was 1.
Furthermore, triethylene glycol was used as the heating medium in the third drawing tank, and the temperature was set at 143°C.The effective length of each cell was 50 cm.During drawing, the first copter roll was rotated. Set speed to 0
．． 5 m/min, and by changing the rotational speed of the fourth codet roll, obtain fibers with the desired drawing ratio.9 At this time, the rotational speed of the second and third codet rolls (9) is selected as appropriate within the range that allows stable drawing. Most of the paraffin wax mixed in is extracted in the first drawing tank and the second drawing tank.The drawing ratio is calculated from the rotational speed ratio of the first copter roll and the fourth codet roll. Strength and elongation at break iL Measured at room temperature (23°C) using a Tensilon RTM-100 tensile tester manufactured by Orientic Co., Ltd. At this time, the sample length between the clamps was 100 tsu, and the tensile speed was 100 mm/
The elastic modulus mentioned here and (9) means the initial elastic modulus, calculated from the slope of the tangent to the stress-strain curve (9) The fiber cross-sectional area IL required for calculation is 0.960 g/cc
Table 1 shows the tensile properties and degree of orientation of the drawn fibers obtained by calculation from the weight.

A molten mixture similar to that described in Example 1 was heated at a shear rate of 41 sec-1 and a shear stress of 3. LX 1×105
Spinning and drawing were carried out in the same manner as in Example 1 except that the temperature was 170°C and the temperature was 170°C.The degree of orientation F of the undrawn fibers was 0.93. Indicates properties and degree of orientation.

The intrinsic viscosity measured in decalin at 135°C is 5.7 dl.
A mixture of the ethylene-1-butene copolymer (ethylene content: 99.8%) and the paraffin wax used in Example 1 at a weight ratio of 30% was melted in the same manner as in Example 1. However, the shear rate at this time was 33 sec-1, and the shear stress was 2.9X 105 dyn/
cm2, and the die temperature was 170°C. The degree of orientation F of this undrawn fiber was 0.91 and the undrawn fiber was further drawn by the method described in Example 1 to obtain a drawn fiber. Table 3 shows the bowing properties of the obtained drawn fiber. and the degree of orientation.

4 salmon 1 Intrinsic viscosity measured in decalin at 135℃ is 7.4 dl
A mixture of 20:80 by weight of high molecular weight polyethylene and the paraffin wax used in Example 1 was melt-spun in the same manner as in Example 1. However, the draft ratio was similar and the shear rate was 415eC-1, shear stress is 2.5X 105 dyn/cm2
The degree of orientation F of this undrawn fiber was 0.94.The undrawn fiber was further drawn by the method described in Example 1 to obtain a drawn fiber.Table 4 shows the tensile properties of the drawn fiber obtained. and the degree of orientation F.

The intrinsic viscosity measured in decalin at 135°C is 8.5 dl.
/H ethylene-propylene copolymer (ethylene content 99.8%) and the paraffin wax used in Example 1 were mixed at a weight ratio of 20:80.
Melt spinning was carried out in the same manner as above, except that the draft ratio at this time was 72 seσ1, the shear rate was 72 seσ1, and the shear stress was 3.
I x 105 dyn/cm2, Gui temperature was 175°C, and the degree of orientation F of this undrawn fiber was 0.94.9 Further, the undrawn fiber was drawn by the method described in Example 1 to obtain a drawn fiber. Table 5 shows the tensile properties and degree of orientation of the drawn fibers obtained.

Comparative Example 1 Intrinsic viscosity measured in decalin at 135°C is 2.8 dl
/g of polyethylene and the paraffin wax used in Example 1 were mixed at a weight ratio of 50:50 and melt-spun and flooded in the same manner as in Example 1. However, the shear rate at this time was 25 sec-1 shear stress. is 1,9X 1×105
The degree of orientation F of this undrawn fiber was dyn/cm2
was 0.85.Furthermore, the undrawn fibers were drawn by the method described in Example 1 to obtain drawn fibers.Table 6 shows the tensile properties and degree of orientation of the drawn fibers obtained.

Comparative Example 2 Intrinsic viscosity measured in decalin at 135°C is 5.6 dl
/g of polyethylene and the paraffin wax used in Example 1 were mixed at a weight ratio of 30 Nia0 to melt-spun by the same method as in Example 1. However, the shear rate at this time was 10 sec. Stress is 1.5X 1X
The degree of orientation F of this undrawn fiber was 0.88 and f, and the undrawn fiber was further drawn by the method described in Example 1 to obtain a drawn fiber. The tensile properties and degree of orientation of the obtained drawn fibers are shown.

＼ ＼ ＼ ＼ ＼ ＼, Group 4 Rainbow Shark 1 The drawn fiber (sample-9) obtained in Example 4 was treated with a corona discharge treatment device manufactured by Tomoe Kogyo Co., Ltd., to form a bar-shaped electrode between electrodes.
The tensile strength of the fiber after corona discharge treatment was performed once under the condition of irradiation dose of 75 W/*min was 2.92 GPa (strength retention rate 94%).T et al. Comparative Example 3 Molecular weight 2.2X 106 A 5:95 (weight ratio) mixture of polyethylene and decalin (intrinsic viscosity 17.0 dl/g measured in decalin at 135°C) was
After spinning under the following conditions, 0.1 part by weight of 3,5-dimethyl-tert-butyl-4-hydroxytoluene was added as a process stabilizer to 100 parts by weight of the mixture, and the mixture was charged into a Seprapul flask sealed with nitrogen. The solution was stirred for 1 hour under heating at 180°C to form a homogeneous solution, and then the solution was put into a spinning tube at 180°C under a nitrogen atmosphere.
The solution was degassed statically for 2 hours at a temperature of
, shear stress 1.2X 105dyn/an2, die temperature 130℃, 30C without applying draft more than twice
After winding two gel filaments onto a bobbin at a speed of In/min, the bobbin is immersed in an n-hexane bath at room temperature to form a gelatinous filament. The liquid component of the filament, decalin, was replaced with n-hexane.Furthermore, the filament was taken out of the n-hexane bath and thoroughly dried under vacuum at 50°C.The degree of orientation F of the obtained undrawn fiber was 0.6. Next, 50 cm of dry fiber was placed in a heat tube sealed with nitrogen.
The effective length of each heating tube was 50 cm, and the temperature inside the first heating tube was 110°C, the temperature inside the second heating tube was 130°C, The temperature inside the third heat tube was 140°C.

The stretching ratio is determined by the rotation ratio of the first codet roll and the fourth codet roll, and the drawing ratio at this time is 60 times.
The rotational speed of the third codetrol was appropriately selected within the range that allowed stable operation.The physical properties of the obtained polyethylene fiber were that the intrinsic viscosity was 14.0 dl/i, the fiber was 21 denier, and the tensile strength was 2.85 GPa. Corona discharge treatment was carried out under the same conditions as in Example 6, and the tensile strength L of the fiber after treatment was 1.75 GPa (retention rate 61%), and the intrinsic viscosity was 6.0 dl/g. (Molecular weight 5. OX 1
05) is an ethylene-butene-1 copolymer (ethylene content 99.9%) and paraffin wax (melting point 69%).
℃, molecular weight 490) at a ratio of 40:60 (weight ratio) was melt-spun under the following conditions.
0.1 part by weight of 4-hydroxytoluene was blended with 100 parts by weight of high molecular weight ethylene-propylene copolymer.9 Next, the mixture was melt mixed using a screw extruder at a set temperature of 190°C, and then mixed. The melt was melt-spun using a spinning gouie with an orifice diameter of 2 mm attached to an extruder at a shear rate of 25 seconds and a gou temperature of 170°C.9 The spun fibers were taken up at a draft ratio of 60 times with an air gap of 180 cm. The degree of orientation of this undrawn fiber is 0.The degree of orientation of this undrawn fiber is 0.
．． The undrawn fibers thus obtained in Example 91 were drawn in the same manner as in Example 1, and the tensile strength and degree of orientation of the drawn fibers obtained in Example 1 are shown in Table 8.

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Claims (1)

[Claims] 1) A molten mixture consisting of polyethylene having an intrinsic viscosity of 3.0 dl/g or more and a diluent is heated at a shear rate of 20 sec^-^1 or more and at a rate of 1 x 10^5 to 8 x 10 ＾5dyn
A method for producing a polyethylene molded article having an orientation degree of 0.7 or more by extruding the polyethylene from a die nozzle while oriented in the die while applying a shear stress of /cm^2. 2) A molten mixture consisting of polyethylene with an intrinsic viscosity of 3.0 dl/g or more and a diluent is heated at a shear rate of 20 sec^-^1 or more and 1 x 10^5 to 8 x 10^5 dyn.
While applying a shear stress of /cm^2, the polyethylene is extruded from a die nozzle while being oriented in the die to obtain a polyethylene molded body with an orientation degree of 0.7 or more, and then the polyethylene molded body is A method for producing a polyethylene stretched molded body that is stretched to the above extent. 3) The manufacturing method according to claim 1 or 2, wherein the content of the polyethylene in the mixture of polyethylene having an intrinsic viscosity of 3.0 dl/g or more and a diluent is 20% by weight or more. 4) The manufacturing method according to claim 1 or 2, wherein the diluent has a melting point of 25° C. or higher.