JPH01156344A - Polyolefin composition - Google Patents

Abstract

PURPOSE:To obtain the title compsn. having excellent wear resistance and impact resistance, causing no delamination and being suitable to obtain an injection-moldable abrasive material, which is comprised of a polyolefin consisting of an ultrahigh MW polyolefin and a low-high MW polyolefin and an abrasive filler. CONSTITUTION:The title compsn. is comprised of 100pts.wt. polyolefin (A) consisting of an ultrahigh MW polyolefin (a) having an intrinsic viscosity of 10-40dl/g measured in decalin solvent at 135<= and a low-high MW polyolefin (b) having an intrinsic viscosity of 0.1-5dl/g measured in decalin solvent at 135 deg.C, wherein the amt. of the component (a) is in the range of 15-40wt.% based on the total amt. of the components (a) and (b), having an intrinsic viscosity [eta]c in the range of 3.5-15dl/g measured in decalin solvent at 135 deg.C and a dissolution torque T of 4.5kg.cm or less, and 1-70pts.wt. abrasive filler (B) (e.g., graphite). It is suitable for obtaining an abrasive material injection- moldable without spoiling wear resistance and impact resistance which the component (a) essentially has and without causing delamination.

Description

Detailed Description of the Invention Technical Field of the Invention The present invention provides a polyolefin composition that has excellent wear resistance and impact resistance, does not cause delamination, and is suitable for obtaining a sliding material that can be injection molded. relating to things.

Technical background of the invention and its problems Conventionally, fluororesins such as polytetrafluoroethylene, polyacetal resins, polyimide resins, etc. have been used as sliding materials. However, these fluororesins
Polyacetal resins and polyimide resins have a problem in that they are expensive and have poor economic efficiency.

In addition, ultra-high molecular weight polyolefins, such as ultra-high molecular weight polyethylene, have better impact resistance, abrasion resistance, sliding properties, and
It has excellent chemical resistance and tensile strength, and can be used as sliding materials.

However, because ultra-high molecular weight polyethylene has an extremely high melt viscosity and poor fluidity compared to general-purpose polyethylene, it is extremely difficult to mold it by ordinary extrusion molding or injection molding, and most of it is molded by compression molding. Currently, only a small portion of the material is extruded into rod shapes at extremely low speeds.

If such ultra-high molecular weight polyethylene, which has poor melt flowability, is molded by normal injection molding, shear failure flow will occur during the process of filling the resin into the mold cavity, and the resulting molded product will have mica-like layers. Peeling occurs, and not only is it impossible to obtain a molded product having the excellent properties of ultra-high molecular weight polyethylene, but the result is often that the molded product is inferior to general-purpose polyethylene molded products.

The applicant has previously developed an injection molding method that does not cause delamination.
A method of slightly enlarging the volume of the mold cavity before resin injection molding or before the end of injection molding, and then compressing it to a predetermined volume (Japanese Patent Publication No. 57-30067, Japanese Patent Publication No. 60
58010@Publication). By employing such a method, it has become possible to obtain an injection molded product that does not cause delamination and has the impact resistance and abrasion resistance that ultra-high molecular weight polyethylene has. However, in order to injection mold ultra-high molecular weight polyethylene using this method, it is necessary to use an injection molding machine equipped with a variable mold cavity mechanism, etc. In any case, it is not possible to use a general-purpose polyethylene injection molding machine as is. The problem was that it was not possible.

On the other hand, various methods have been proposed for improving the melt fluidity of ultra-high molecular weight polyolefins, including mixing ultra-high molecular weight polyolefins with low to high molecular weight polyolenoins.

For example, JP-A-57-177036 discloses an ultra-high-molecular-weight polyethylene with improved moldability, which is made of 100 parts by weight of ultra-high molecular weight polyethylene with a molecular weight of 1 million or more and 10-60 parts by weight of low-molecular-weight polyethylene with a molecular weight of 15,000 to 20,000. Molecular weight polyethylene compositions are disclosed. JP-A-57-177036 states that when molding a 50 m thick slab by compression molding, the moldability of the above-mentioned ultra-high molecular weight polyethylene composition is 200° C. The 3-hour molding cycle was improved to a 200'C x 2-hour molding cycle, and it is also stated that in the ram extrusion method, the pipe extrusion speed was similarly improved from 5 cm/min to 10 cm/min. However, when such an ultra-high molecular weight polyethylene composition containing a large amount of ultra-high molecular weight polyethylene is molded using a normal injection molding machine, the resulting molded product may undergo layer delamination, making it difficult to obtain a molded product with good performance. It is not possible.

Furthermore, JP-A-59-126446 discloses an ultra-high molecular weight polyethylene resin composition obtained by mixing 95 to 50 parts by weight of an ultra-high molecular weight polyethylene resin and 5 to 50 parts by weight of a general-purpose polyolefin resin. ing. JP-A-59-126446 discloses a composition using a silane-modified polyethylene resin with a melt index of 2.5 or 5.0 y/10 min as a general-purpose polyolefin resin. It's been done -〇
However, as shown in Table 1 of the same publication, the moldability is not sufficiently good for all compositions. Similar to the above-mentioned compositions, such ultra-high molecular weight polyethylene resin compositions also contain a large amount of ultra-high molecular weight polyethylene components, and the problem of delamination of the resulting injection molded products remains unresolved.

On the other hand, Japanese Patent Publication No. 58-41309@publication describes 85 to 50 parts by weight of polyethylene with a viscosity average molecular weight of 500,000 to 150,000, and granular superethylene with a viscosity average molecular weight of 1 million or more and a particle size of 10 mesh or less. High molecular weight polyethylene 1
A polyethylene composition containing 5 to 50 parts by weight is disclosed.

As described in Column 3, lines 17-28 of the same publication, this polyethylene composition does not improve the moldability of ultra-high molecular weight polyethylene, but uses the powdery state of ultra-high molecular weight polyethylene to create a different shape. The purpose is to reduce the orientation and provide molded products with excellent impact resistance. Moreover, such a composition, which is a mechanical mixture of polyethylene and granular ultra-high molecular weight polyethylene, has a large melting torque, and even when molded with a normal injection molding machine, delamination occurs in the molded product as described above. cannot be prevented.

Also, Japanese Patent Publication No. 59-10724M and Japanese Unexamined Patent Publication No. 57
- "14" No. 1409 discloses a method of continuously polymerizing polyethylenes having different molecular weights in multiple stages in three or more polymerization vessels. However, the purpose of all of these methods is to produce polyethylene with improved die swell during extrusion molding, particularly blow molding (a), and is not concerned with improving injection molded products. Furthermore, even if the content of ultra-high molecular weight polyethylene specifically described in the above-mentioned publication is 10% by weight or less, and the MI of the composition is 0.3i or the intrinsic viscosity [η] is 2.
．． 3-3. Od, Il /9 (approximately 0 when converted to MI
．． Even if a composition with 2 to 0.8) is injection molded, the content of ultra-high molecular weight polyethylene is very small at 10% by weight or less, so it is difficult to produce injection molded products with excellent wear resistance and impact resistance. You can't get it.

Furthermore, Japanese Patent Publication No. 46-1134.9 discloses that in the first step, 5 to 30% by weight of an ethylene/α-olefin copolymer having a reduced specific viscosity of 30 to 5 is polymerized, and in the second step, the reduced specific viscosity is Polyethylene or ethylene with a value of 4.6 to 1.5
A method of polymerizing an alpha-olefin copolymer to obtain a polymer homogeneously mixed with said polymer is disclosed. However, the purpose thereof is to improve the moldability in extrusion molding of bottles, cables, tubes, etc., as mentioned above, and is not concerned with improving injection molded products. Also, even if it is specifically stated in such a publication [η]
Even if a composition having a hardness of 2.9 is injection molded, the resulting molded product will have poor abrasion resistance, impact resistance, etc.

Furthermore, when a sliding material is formed from the above-mentioned ultra-high molecular weight polyolefin, it is desired to further improve the opening properties of the resulting sliding material.

Purpose of the Invention The present invention aims to solve the problems associated with the prior art as described above, and aims to improve the excellent mechanical properties inherently possessed by ultra-high molecular weight polyolefins, such as abrasion resistance and impact resistance. It is an object of the present invention to provide a polyolefin composition suitable for obtaining a sliding material that can be injection molded without impairing the properties or causing delamination.

Summary of the invention ゛The polyolefin composition according to the present invention comprises (A) (i>1
Intrinsic viscosity [η] measured in decalin solvent at 35°C
-40 tlj/y ultra-high molecular weight polyolefin;
The ultra-high molecular weight polyolefin consists essentially of a low molecular weight to high molecular weight polyolefin having an intrinsic viscosity [η] of 0.1 to 5 d, Qzl as measured in a decalin solvent at 135°C; It is in the range of 15 to 40% by weight based on the total weight of the polyolefin and the above-mentioned low molecular weight to high molecular weight polyolefin, and the intrinsic viscosity [η]C measured in a decalin solvent at >135°C is 3.5 to 15 dβ/ (1v) 100 parts by weight of a polyolefin with a melting torque of 4.5 kg/cm or less, and (B) 1 to 70 parts by weight of a sliding filler. .

DETAILED DESCRIPTION OF THE INVENTION The polyolefin composition according to the present invention will be specifically described below.

Polyolefin (A) The polyolefin used in the present invention consists of an ultra-high molecular weight polyolefin and a low-molecular weight to high-molecular weight polyolefin, and the ultra-high molecular weight polyolefin and the low-molecular weight to high molecular weight polyolefin will be explained below.

135 of the ultra-high molecular weight polyolefin used in the present invention
Intrinsic viscosity measured in °C decalin solvent [η] - 10
~4.0dl/4. Preferably 15-35d, 117g
Within the range of This intrinsic viscosity [η] is 10d, l! /
If it is less than y, the mechanical properties of the injection molded product tend to be poor, which is undesirable. On the other hand, if it exceeds 40d, Q/ff, the appearance of the injection molded product will be poor, flow marks will occur,
Moreover, this is not preferable because it causes delamination.

The intrinsic viscosity [η
]h is 0.1-5d, 117g, preferably 0.5-5d
It is in the range of 3 dll/g. This intrinsic viscosity [η]h is 0
．． 1d, I) If it is less than 7 g, the molecular weight is too low and there is a risk of bleeding to the surface of the injection molded product, so it is not preferable, while 5d, I! If it exceeds /9, melt fluidity decreases, making it difficult to use a general-purpose polyethylene injection molding machine as is, which is not preferred.

The ultra-high molecular weight polyolefins and low molecular weight to high molecular weight polyolefins mentioned above include, for example, ethylene,
α of propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 4-methyl-1-pentene, 3-methyl-1-pentene, etc.
- Consists of homopolymers or copolymers of olefins. Among these, ethylene homopolymers or copolymers of ethylene and other α-olefins, with ethylene as the main component, are desirable.

In the polyolefin according to the present invention, the ultra-high molecular weight polyolefin and the low-molecular weight to high-molecular weight polyolefin are present in such a proportion that the ultra-high molecular weight polyolefin occupies 15 to 40% by weight with respect to the total weight of both polyolefins. In other words, the low molecular weight to high molecular weight polyolefins are present in a proportion of 85 to 60% by weight based on the total weight of both polyolefins. The ultra-high molecular weight polyolefins mentioned above are
Preferably, it is present in a proportion of 20 to 35% by weight based on the total weight of both polyolefins. The amount of ultra-high molecular weight polyolefin is less than 15% by weight,
This is not preferable because the mechanical properties of the resulting injection molded product tend to be poor; on the other hand, if it exceeds 40% by weight, delamination will occur in the resulting injection molded product, resulting in a molded product with good mechanical properties. This is not desirable because it cannot be used.

The polyolefin used in the present invention essentially consists of an ultra-high molecular weight polyolefin and a low to high molecular weight polyolefin, which are present in the above quantitative proportions.

Therefore, the polyolefin used in the present invention has 13
The intrinsic viscosity [η]C measured in a decalin solvent at 5°C is 3.
5 to 15d, Il/g, and the melting torque T'<
Ky・cm") is 4.5! J・cm or less. Here, the melting torque T is determined by the JSR Curastometer (
(manufactured by Imao Kikai Kogyo KK) under the conditions of a temperature of 240'C, a pressure of 5 Kg/cti, an amplitude of 3° and a frequency of 6 CPH.

The above [η] is 3. If '5' dj is less than 1, the resulting injection molded product may have poor mechanical strength, especially wear resistance, so it is not preferable. On the other hand, if [η] is 156
．． I! If it exceeds /y, delamination will occur in the obtained molded product, resulting in a decrease in mechanical strength such as wear resistance, which is not preferable.

Moreover, if the melting torque T exceeds 4.5'j·cm, it is not preferable because it will not bite into a normal screw during molding and injection molding will not be possible with a general-purpose injection molding machine.

The polyolefin used in the present invention is preferably [η
]C is 4. It is in the range of O to 10d, Il/y.

The polyolefin used in the present invention can also be prepared by blending an ultra-high molecular weight polyolefin and a low-molecular weight to high-molecular weight polyolefin in the above proportions, but according to the test equipment of the present inventors, a specific Polyolefins obtained by the following multi-step polymerization method in which olefins are polymerized in multiple steps in the presence of a catalyst formed from a highly active solid titanium catalyst component and an organoaluminium compound catalyst component have excellent properties. I can see what you're doing.

Such a multi-step polymerization method is carried out in the presence of a Daegler-type catalyst formed from a highly active titanium catalyst component (a) containing magnesium, titanium and halogen as essential components, and an organoaluminum compound catalyst component (b). , carried out by multi-stage polymerization of olefins.In at least one polymerization step, the intrinsic viscosity is 10 to 40 d,
An ultra-high molecular weight polyolefin with Q/=J is produced, and in another polymerization step, the olefin is polymerized in the presence of hydrogen to produce a low to high molecular weight polyolefin with an intrinsic viscosity of 0.1 to 5 dρ/q.

The particular Ziegler type catalyst used is essentially a catalyst of a particular nature formed from a solid titanium catalyst component and an organoaluminum compound catalyst component. As the solid titanium catalyst component, it is preferable to use, for example, a highly active fine powder catalyst component with a narrow particle size distribution and an average particle size of about 0.01 to 5 μm, and in which a few microspheres are fixed. be. A highly active finely powdered titanium catalyst component having such properties is obtained, for example, in the solid titanium catalyst component disclosed in JP-A No. 56-811, by bringing a liquid magnesium compound into contact with a liquid titanium compound. When precipitating a solid product, it can be manufactured by strictly adjusting the precipitation conditions. Specifically, in the method disclosed in JP-A-56-811, a hydrocarbon solution in which Magnesium chloride = 16-rum and a higher alcohol are dissolved and titanium tetrachloride are mixed at a low temperature, and then 50% ~100'C
When heating to a moderate temperature to precipitate a solid product, a trace amount of monocarboxylic acid ester of about 0.01 to 0.2 mol is allowed to coexist with 1 mol of magnesium chloride, and under strong stirring conditions. By performing this precipitation, a highly active finely powdered titanium catalyst component can be prepared. If necessary, it may be washed with titanium tetrachloride.

In this way, a solid catalyst component having excellent activity and particle state can be obtained. Such catalyst components are
For example, it contains about 1 to about 6% by weight of titanium, the halogen/titanium (atomic ratio) is about 5 to about 90, and the magnesium/titanium (atomic ratio) is about 5 to about 90.
Titanium (atomic ratio) ranges from about 4 to about 50.

Furthermore, the slurry of the solid titanium catalyst component prepared as described above is sheared at high speed, and the particle size distribution is narrow and the average particle size is 0.01 to 5μ7.
Microspheres of rL, preferably in the range of 0.05 to 3 μm, are also suitably used as the highly active finely powdered titane catalyst component. Specifically, the high-speed shearing treatment may be carried out by, for example, treating a slurry of solid titanium catalyst components in an inert gas atmosphere with a commercially available homomixer for an appropriate period of time. In this case, for the purpose of preventing deterioration of catalyst performance, a method may be adopted in which titanium and an organic aluminum compound are added in an equimolar amount in advance. Roughly,
It is also possible to adopt a method in which the treated slurry is filtered through a sieve to remove coarse particles. By these methods, the highly active fine powdered titanium catalyst component having the fine particle size can be obtained.

The polyolefin used in the present invention is produced by using the highly active finely powdered titanium catalyst component (a) and the organoaluminum compound catalyst component (b) as described above, together with an electron donor if necessary, and by using pentane, hexane, etc. It can be produced by slurry polymerizing an olefin in a multi-stage polymerization process of at least two stages in a hydrocarbon medium such as , heptane or kerosene, usually at a temperature in the range of 0 to 100'C.

Examples of the organoaluminum compound catalyst component (b) include trialkylaluminum such as triethylaluminum and triisobutylaluminum, siaaluminum chloride such as diethylaluminum chloride and diisobutylaluminum chloride, and alkylaluminum sesquichloride such as ethylaluminum sesquichloride. or a mixture thereof is preferably used.

In the multistage polymerization process of the olefin, a multistage polymerization apparatus in which at least two or more polymerization vessels are usually connected in series is employed, such as a two-stage polymerization method, a three-stage polymerization method,... an n-stage polymerization method. will be implemented. It is also possible to perform a multi-stage polymerization method using a batch polymerization method in one polymerization tank. It is necessary to produce a specific amount of ultra-high molecular weight polyolefin in at least one polymerization vessel of the multi-stage polymerization process. The polymerization step for producing the ultra-high molecular weight polyolefin may be a first stage polymerization step,
It may be an intermediate polymerization step or may be a multiple stage of two or more stages. It is preferable to produce an ultra-high molecular weight polyolefin in the first stage polymerization step because the polymerization treatment operation is easy and the physical properties of the resulting polyolefin can be easily controlled. In the polymerization step, 15 to 4 of the polyolefin used in the present invention is
0% by weight means that the intrinsic viscosity [η], (13 in decalin solvent)
It is necessary that the ultra-high molecular weight polyolefin has an ultra-high molecular weight polyolefin of 10 to 40 d, Il/9 (value measured at 5° C.), and furthermore, 18 to 37% by weight of the polyolefin used in the present invention, especially 21 ~35% of the weight has an intrinsic viscosity [η]U of 15 to 35d, l)/9, especially 18
Preferably, the ultra-high molecular weight polyolefin has a molecular weight of ~30 dj/y. In this polymerization process, the intrinsic viscosity of the ultra-high molecular weight polyolefin produced is η
'' is less than 10 dfJ/9, and even if the ultra-high molecular weight polyolefin produced in the polymerization step is outside the range of 15 to 40% by weight, it is difficult to obtain a polyolefin that can be indexed.

In the multi-stage polymerization step, in the polymerization step for producing an ultra-high molecular weight polyolefin, polymerization is carried out in the presence of a catalyst consisting of the highly active titanium catalyst component (a) and the organoaluminum compound catalyst component (b). Polymerization can be carried out by a gas phase polymerization method or by a liquid phase polymerization method. In either case, in the polymerization step to produce the ultra-high molecular weight polyolefin, the polymerization reaction is optionally carried out in the presence of an inert medium. For example, gas phase polymerization is carried out in the presence of a diluent consisting of an inert medium, if necessary, and liquid phase polymerization is carried out, if necessary, in the presence of a solvent consisting of an inert medium.

In the polymerization step for producing the ultra-high molecular weight polyolefin, the highly active titanium catalyst component (a) is used as a catalyst, for example, in an amount of about 0, OO1 to about 1 to about 1 milligram atom, preferably about 0.005 to about 1 milligram atom of titanium per 1 p of the medium. 10 mg atoms, organoaluminum compound catalyst component (b),
It is preferable to use such a ratio that AI/Ti (atomic ratio) is about 0.1 to about 1000, particularly about 1 to about 500.

The temperature of the polymerization step to produce the ultra-high molecular weight polyolefin is usually about -20 to about 120°C, preferably about O
to about 100'C1, particularly preferably from about 5 to about 95C. Further, the pressure during the polymerization reaction is within a pressure range that allows liquid phase polymerization or gas phase polymerization at the above temperature, for example, atmospheric pressure to about 100 Kg/cri, preferably atmospheric pressure to about 50 Kg/cri. range. The polymerization time in the polymerization step may be set so that the amount of prepolymerized polyolefin produced is about 10,009 or more, preferably about 2,000 g or more per milligram atom of titanium in the highly active titanium catalyst component. Moreover, in the polymerization step, in order to produce the ultra-high molecular weight polyolefin, it is preferable to carry out the polymerization reaction in the absence of hydrogen. Furthermore, after carrying out the polymerization reaction, it is also possible to temporarily isolate and store the polymer under an inert medium atmosphere.

Inert media that can be used in the polymerization process to produce the ultra-high molecular weight polyolefin include, for example, propane, butane, pentane, hexane, heptane,
Aliphatic hydrocarbons such as octane, decane, and kerosene; Alicyclic hydrocarbons such as cyclopentane and cyclohexane; Aromatic hydrocarbons such as benzene, monochrome, and xylene; Dichloroethane, methylene chloride, and and halogenated hydrocarbons such as benzene; or mixtures thereof. Particularly desirable is the use of aliphatic hydrocarbons.

In addition, when manufacturing the polyolefin used in the present invention, hydrogen is A polymerization reaction of the remaining olefin is carried out in the presence of the olefin. If the polymerization process for producing the ultra-high molecular weight polyolefin is the first stage polymerization process, then the second stage and subsequent polymerization processes correspond to the polymerization process. If the polymerization step is located after the ultra-high molecular weight polyolefin producing polymerization step,
A polyolefin containing the ultra-high molecular weight polyolefin is supplied to the polymerization step, and when the polymerization step is performed after a polymerization step other than the ultra-high molecular weight polyolefin-producing polymerization step, the low molecular weight or high molecular weight produced in the previous step is supplied. The polyolefin is fed and the polymerization is carried out in each case continuously. At that time, the polymerization step usually includes
Feedstock olefin and hydrogen are supplied. When the polymerization step is the first stage polymerization step, a catalyst consisting of the highly active titanium catalyst component (a) and the organoaluminum compound catalyst component (a) is supplied, and the polymerization step is the second stage polymerization step.
In the case of subsequent polymerization steps, the catalyst contained in the polymerization liquid produced in the previous step can be used as is, or the highly active titanium catalyst component (a) and/or the catalyst may be used as necessary. Alternatively, it is okay to additionally supplement the organic aluminum compound (b).

The low molecular weight to high molecular weight polyolefin thus obtained is 5 to 70% by weight, preferably 20 to 60% by weight, based on the total olefin components polymerized in the entire polymerization process.
, particularly preferably in an amount of 25 to 55% by weight.

The hydrogen supply ratio in the polymerization steps other than the ultra-high molecular weight polyolefin producing polymerization step is usually 0.01 to 5 mols of hydrogen per mole of olefin supplied to each polymerization step.
0 mol, preferably in the range of 0.05 to 30 mol 1
The concentration of each catalyst component in the polymerization product liquid in the polymerization tank in the polymerization step other than the ultra-high molecular weight polyolefin production polymerization step is approximately 0 per 1 ρ of polymerization volume in terms of titanium atoms of the treated catalyst. .001 to about 0.1 milligram atoms,
It is preferably about 0.005 to about 0.1 milligram atoms, and the AI/Ti (atomic ratio) of the polymerization system is about 1 to about 1000,
Preferably, it is adjusted to about 2 to about 500. For this purpose, an organoaluminum compound catalyst component (b) can be additionally used as necessary. In addition, hydrogen/electron donors, halogenated hydrocarbons, etc. may be present in the polymerization system for the purpose of controlling the molecular weight, molecular weight distribution, etc.

The polymerization temperature is within a temperature range that allows slurry polymerization and gas phase polymerization, and is about 40'C or higher, more preferably about 50 to about 10°C.
A range of 0'C is preferred. Further, the polymerization pressure is, for example, atmospheric pressure to about 100 K! j/cri, particularly the range from atmospheric pressure to about 50'j/c/7i. The amount of polymer produced is about 10,009 or more, particularly preferably about 50,009 or more per milligram atom of titanium in the titanium catalyst component.
It is preferable to set the polymerization time such that the polymerization time is 009 or more.

Polymerization steps other than the polymerization step for producing an ultra-high molecular weight polyolefin can be similarly carried out by a gas phase polymerization method or a liquid phase polymerization method. Of course, it is also possible to employ different polymerization methods in each polymerization step. Among the liquid phase polymerization methods, a slurry suspension polymerization method is preferably employed.

In either case, the polymerization reaction is usually carried out in the presence of an inert medium in the polymerization step. For example, gas phase polymerization processes are carried out in the presence of an inert medium diluent, and liquid phase slurry suspension polymerization processes are carried out in the presence of an inert medium solvent.

Examples of the inert medium include the same inert media exemplified in the polymerization process for producing the ultra-high molecular weight polyolefin.

Polyolefin composition obtained in the final stage polymerization process [
η]C is usually 3.5 to 15d, l! /y, preferably 4.0 to 10dβ/g, melting torque 4.5Kg・c
The polymerization reaction is carried out in such a way that the total molecular weight is equal to or less than m.

The multi-step polymerization method can be carried out in a batch, semi-continuous or continuous manner.

The olefins to which the multi-stage polymerization method can be applied include:
As mentioned above, ethylene, propylene, 1-butene, 1-
Pentene, 1-hexene, 1-octene, 1-decene,
Examples include α-olefins such as 1-dodecene, 4-methyl-1-pentene, and 3-methyl-1-pentene, and it can also be applied to a method for producing homopolymers of these α-olefins. , it can also be applied to a method for producing a copolymer consisting of two or more mixed components. , these α−
Among olefins, it is preferable to apply the method of the present invention to a method for producing an ethylene polymer having ethylene as a main component, which is ethylene or a copolymer of ethylene and another α-olefin.

Sliding filler (B) A polyolefin composition suitable for producing the sliding material according to the present invention contains a sliding filler (B> in addition to the above polyolefin (A>). There is.

As the sliding filler (B), conventionally known sliding fillers can be used without particular limitation, but specifically the following compounds are used.

Grapheye 1 - Powder, Polyte 1 - Lafluoroethylene resin (PTFE), Tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP), Tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (PFA)
, trifluorochloroethylene resin (PCTFE), tetrafluoroethylene-ethylene copolymer resin (FTFE), fluororesin powder such as vinylidene fluoride resin, molybdenum fluoride powder, molybdenum sulfide powder, titanium oxide powder, polyfluoride enylene sulfide resin powder, etc.

These sliding fillers (B) are preferably used in powder form, and the particle size is preferably 1 to 100 μm, preferably 10 to 50 μm.

In the polyolefin composition according to the present invention, the sliding filler (B) as described above is 1 to 70 parts by weight, preferably 3 to 50 parts by weight, more preferably 5 parts by weight, based on the polyolefin (A>100 parts by weight). ~30 parts by weight is used.

The amount of this sliding filler (B) is 1
If the amount exceeds 70 parts by weight, the melt viscosity of the resin increases and injection moldability is impaired, which is not preferable.

In addition to the above-mentioned components (A) and (B), the injection moldable polyolefin composition according to the present invention contains, for example, a phenolic stabilizer, an organic phosphite stabilizer, an organic thioether stabilizer, and a higher fatty acid. This includes stabilizers such as metal salts, pigments, dyes, lubricants, inorganic fillers or reinforcing agents such as carbon black, talc, and glass fibers, flame retardants, neutron blocking agents, and other compounding agents that are usually added to polyolefins. It can be added within a range that does not impair the purpose of the invention.

Effects of the Invention The polyolefin composition according to the present invention has excellent mechanical properties such as impact resistance, abrasion resistance, chemical resistance, lubricity, water absorption, etc., which are possessed by ultra-high molecular weight polyolefins. Moreover, it can be injection molded without the delamination of molded products that occurs when using general-purpose injection molding machines, which is a major drawback of ultra-high molecular weight polyolefins, and it also has excellent sliding properties. It is particularly suitable for manufacturing materials.

[Example] 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 unless they go beyond the gist of the invention.

Example 1 Catalyst Preparation> Anhydrous magnesium chloride 47.6 g (0.5 mol), decalin 0.25 g. Qct: After heating 0.23 fJ (1.5 mol) of 3 and 2-ethylhexyl alcohol at 130'C for 2 hours to make a homogeneous solution, edyl benzoate 7.
4 (50 mmol) was added. Add 50% of this homogeneous solution.
1.59° C. was added dropwise under stirring over a period of 1 hour.

A 3fJ glass separable flask was used as the reactor, and the stirring rate was 950 ppm.

After the dropwise addition, the temperature was raised to 90'C, and a reaction was carried out at 90'C for 2 hours. After the reaction was completed, the solid portion was collected by filtration and thoroughly washed with hexane to obtain a highly active finely powdered titanium catalyst component. The catalyst component contained 3.8% by weight of titanium atoms.

<Polymerization> Continuous polymerization was carried out using a continuous two-stage polymerization apparatus in which two polymerization tanks each having an internal volume of 220 M were connected in series.

Add 130.11 l of n-hexane to the first stage polymerization tank (hereinafter abbreviated as polymerization tank 1) of the continuous two-stage polymerization apparatus,
The temperature was raised to 60°C. n-hexane at a rate of 35r/hour, triethylaluminum at a rate of 45rTIM7 hours, titanium catalyst at a rate of 1.0 milligram atoms/hour as titanium atoms, and ethylene gas at a rate of 4.3N but/hour. It was continuously introduced into the polymerization tank 1. Using a pump, the polymerization mixture slurry in polymerization tank 1 is transferred to the subsequent polymerization tank (
(hereinafter abbreviated as polymerization tank 2), and set the level of polymerization tank 1 to 1.
I kept it at 30. At that time, the polymerization pressure in polymerization tank 1 was 4,
, I got it with 7 Ky/criG.

In addition to the polymerization mixture slurry sent from the polymerization tank 1, n-hexane was added to the polymerization tank 2 at a rate of 25ρ/hour.
Ethylene gas was continuously introduced at a rate of 11.2 N/hour. Further, an appropriate amount of hydrogen gas was added to adjust the composition (molar ratio) of the gas phase portion of the polymerization tank 2 to 1000 parts of ethylene and 30 parts of hydrogen. The slurry produced by the polymerization reaction was intermittently discharged from the lower part of the polymerization tank 2 using a timer valve, and the level of the polymerization tank 2 was maintained at '120ρ.

Polymerization temperature in polymerization tank 2 is 85℃ 1 polymerization pressure is 7.2Ky
/ CIIrG. The obtained polymer and solvent were separated by a centrifuge and dried under a N2 stream.

[η] of the obtained polyolefin (A>, melting torque T
was measured by the following method.

[η]: Intrinsic viscosity measured in decalin solvent at 135°C Melting torque (min): Using a JSR Curus 1-meter (manufactured by Imyo Kikai Kogyo), temperature 240°C1 pressure 5p/m
crA, amplitude ±3°C, frequency 6 Stress torque of sample in molten state measured by CPM (injection molding) G-tert-
butyl-4-hydroxy)hydrocinnamate]methane (trade name IRGANOX, 1010, Nippon Chiba Kaigyu)
(l wood) 0.1 car ff 4 parts, Te] ~ Rakis (2,4-
Di-tert-butylphenyl)-4,4-biphenylene siphosphite (trade name: Zandstap P-EPQ)
0.1 part by weight of calcium stearate (manufactured by NOF Corporation) and 0.12 parts by weight of calcium stearate (manufactured by NOF Corporation) and graph'-33-ite powder (product name C3P, manufactured by Nippon Graphite Industries Ltd.) as a sliding filler. ) with 10 parts by weight in a Henschel mixer, this composition was mixed with L
/D = 28.25 mm single screw extruder and heated at 190°C
, 50 ppm for one pass, kneading, and granulation. The granulated pellets were molded using an injection molding machine (L5-50 manufactured by Toshiba Corporation).
> under the following conditions: square plate (130x120x2m
) was molded and cut to create a test piece.

Injection molding conditions Cylinder temperature (℃): 200 meters 230/270/27
0; Injection pressure (K'j/cd): Primary/Secondary -1
000/800 Cycle (sec): Primary/Secondary/Cooling-5/3
/25; Injection speed (-): 2/10 SCREW rotation speed (rpm): 97; Mold temperature (°C): Water cooling (32°C) The physical properties of the sample were evaluated by the following method.

Tensile test: △STM D 638, however, the test piece shape was Ascho M No. 4, the tensile speed was 50#/min, and the yield point stress was 3I11. - (YS: Kg/crtt"), tensile strength at break (T
S: K9/ci> and elongation at break (EL:%) were determined.

Izotsu impact strength W (K9 ・cm/cm>: AS
The test was conducted according to TMD 256 using a notched test piece.

Olzen rigidity (Kg/cut>: △STM D747
According to.

Friction and wear test: A Matsubara friction and wear tester (manufactured by Toyo Baldwin) was used for 24 hours under the conditions of a compressive load of 3.4 kg/crA and a sliding speed of 30 m/min to determine the amount of wear loss and the coefficient of friction.

Example 2 PTFE powder (product name: Teflon-T) as a sliding filler
FE-T-TA-J: Mitsui DuPont Fluorochemical ■
The same procedure as in Example 1 was carried out except that 10 parts by weight (manufactured by Manufacturer Co., Ltd.) was used.

The results are shown in Table 1.

Comparative Examples 1 to 2 35 The same procedure as in Example 1 was carried out except that the graphite powder used in Example 1 was changed to 3 parts by weight and 80 parts by weight, respectively.

The results are shown in Table 1.

−36=

Claims (1)

[Scope of Claims] 1) (A) (i) An ultra-high molecular weight polyolefin having an intrinsic viscosity of 10 to 40 dl/g as measured in a decalin solvent at 135°C and an intrinsic viscosity of 0 as measured in a decalin solvent at 135°C.
．． (ii) the ultra-high molecular weight polyolefin has a molecular weight of 1 to 5 dl/g, and (ii) the ultra-high molecular weight polyolefin has a , in the range of 15 to 40% by weight, (iii) the intrinsic viscosity [η]_C measured in a decalin solvent at 135°C is in the range of 3.5 to 15 dl/g, and (iv) the dissolution torque T is 4. An injection moldable polyolefin composition comprising: 100 parts by weight of a polyolefin having a weight of 5 kg/cm or less; and (B) 1 to 70 parts by weight of a slidable filler. 2) The sliding filler is graphite, fluororesin powder,
The polyolefin composition according to claim 1, which is molybdenum fluoride, molybdenum sulfide, or polyphenylene sulfide resin powder. 3) The above polyolefin is produced in at least one polymerization step in the presence of a Ziegler type catalyst formed from a highly active titanium catalyst component (a) containing magnesium, titanium and halogen as essential components and an organoaluminum compound catalyst component (b). In the step, olefins are polymerized to produce ultra-high molecular weight polyolefins with an intrinsic viscosity of 10 to 40 dl/g, and in other polymerization steps, olefins are polymerized in the presence of hydrogen to produce ultra-high molecular weight polyolefins with an intrinsic viscosity of 0.1 to 5 dl/g. The polyolefin composition according to claim 1, which is produced by a multi-step polymerization method to produce a polyolefin having a molecular weight to a high molecular weight.