JPS5812284B2 - Ethylene diyugoutaino - Google Patents

Description

Detailed Description of the Invention [I] Background of the Invention The present invention has a wide molecular weight distribution, good extrusion moldability,
This invention relates to a method for producing an ethylene polymer having suitability for blow molding, film molding, etc.

Ethylene polymers are useful as resin materials for various molded products, but these molded products are required to have good surface properties; for example, in blow molded products, surface roughness (
It is necessary that there is no so-called sharkskin.

However, in ethylene polymers produced using a catalyst made of a combination of ordinary titanium trichloride and organoaluminum, the surface roughness is generally significant.

The occurrence of surface roughness is closely related to the molecular weight distribution of the polymer used, and it is thought that the wider the molecular weight distribution of the polymer used, the less surface roughness will occur.

As a measure of the breadth of the molecular weight distribution, the FR value (which is the ratio of the melt index at a load of 2.16 kg and 10 kg)
1MI,.

/MI2) is used, and it is thought that the larger the FR value, the wider the molecular weight distribution. However, in order to obtain molded products with good surface properties, it is necessary to use a polymer with an FR value of about 15 or more. It is necessary to use it.

Summary of the Invention (Summary) The purpose of this invention is to solve the above-mentioned problem of molecular weight distribution and to produce an ethylene polymer having good extrusion molding suitability, blow molding suitability, film molding suitability, etc. As a transition metal component in the catalyst, titanium chloride,
A composition obtained by co-milling a magnesium halide and a halogenated silicon compound or a halogenated carbon compound is used, and diolefin and 2AIR3 (where R is a hydrogen atom or a hydrocarbon residue) are used as organoaluminum components. It is intended to achieve this objective by using a reaction product obtained by reaction with a compound (which is a radical).

Therefore, the method for producing an ethylene polymer according to the present invention is characterized in that ethylene is brought into contact with a catalyst consisting of a combination of component I) and component (2) below for polymerization.

■) Solid composition obtained by mixing and grinding the following components (1) to (3): (1) titanium trichloride (2) halide of magnesium; and (3) halogen compound represented by the general formula below. Silicon compound or halogenated carbon compound SiXnR CX R-4n1 n4n (where X is a halogen atom, R is a hydrogen atom or a hydrocarbon residue, n is an integer of 1 to 4) diolefin and the following general formula is a reaction product with the represented compound;
and an organoaluminum compound in which the ratio of the number of groups derived from diolefin to the number of H is in the range of 0.25 to 2.

AIR3 (R represents a hydrogen atom or a hydrocarbon residue.

) (Effect) If a catalyst consisting of the above component I) and component ■) is used,
The molecular weight distribution of the produced ethylene polymer becomes wider, and F
The R value can be increased to about 25.

This PR value varies from 15 to 15 depending on polymerization conditions, catalyst manufacturing conditions, etc.
It can be freely controlled directly between 25 and can be used for many purposes such as the above-mentioned blow molding.

As a conventionally known method, a reaction product of an aluminum compound such as trialkylaluminum or aluminum hydride and a diolefin such as isobrene is used as an organoaluminum component.

There is a method described in Japanese Patent Publication No. 40-5411, but the ratio of the number of groups derived from the aforementioned diolefin to the number of H is 2.
Because of the above, it has the disadvantage of being extremely viscous and difficult to handle, and the produced polymer has a narrow molecular weight distribution.

In contrast, the present invention has the effect of widening the molecular weight distribution.

Furthermore, the method described in Japanese Patent Publication No. 47-16645 uses an organoaluminum similar to the reaction product of component (1) of the present invention; A chemically bonded solid complex is used, and the molecular weight distribution of the resulting polymer is
Not wide enough to be suitable for blow molding grade.

Therefore, it is presumed that with this catalyst, the molecular weight distribution becomes extremely wide due to the specific action between component I) and component (2), unlike the above-mentioned known technology.

(■) Specific description of the invention 1. Catalyst (1) Component I) Titanium trichloride Titanium trichloride is obtained by reducing titanium tetrachloride with hydrogen (T i C I 3 (H)).
, reduced with titanium metal (TiCIa(T)),
Reduced with aluminum metal [TiCI3(A)]
, reduced with organoaluminum compounds (e.g. titanium trichloride by diethylaluminum chloride reduction)
, those reduced with silicon hydride compounds (e.g. titanium trichloride by hydromethylpolysiloxane reduction), etc.
There are many other types.

In the present invention, the catalytic performance obtained is not necessarily the same (depending on the type of titanium trichloride used, there may be differences in catalytic activity and molecular weight distribution),
Anything that can be used as the titanium trichloride component of so-called Ziegler catalysts (including Ziegler-Natsuta catalysts) can be used.

Therefore, this titanium trichloride does not need to be pure TiCIs; for example, it can be one to which a small mol of AIC3 has been added like TtCIs (A), or it can be one in which such an auxiliary component has been introduced afterwards. Also, unreduced amounts of unreduced TiCI may be used unavoidably or purposefully.
4 or overreduced T i CI2 or an oxidation product of a reducing agent.

Magnesium halide MgX2 (X = halogen atom) Specifically, MgF2, MgC2, MgBr2) Mg
There is I2.

Halogenated silicon compounds, halogenated carbon compounds It is expressed by the following general formula.

S i XnR4- n , CXn R4 n where X is a halogen atom, R is a hydrogen atom or a hydrocarbon residue,
n represents an integer of 1 to 4.

As the halogen atom, chlorine, bromine, and iodine are preferable.

Hydrocarbon residues include straight chain, branched chain, alkyl, cycloalkyl, aralkyl, aryl, alkaryl, etc.
It may be saturated, unsaturated or cyclic.

The number of carbon atoms is preferably 8 or less.

Specific examples of the silicon halide compound include silicon tetrachloride, trichlorosilane, methyltrichlorosilane, ethyltrichlorosilane, dichlorodiethylsilane, triethylchlorosilane, and phenyltrichlorosilane.

Examples of halogenated carbon compounds include carbon tetrachloride, chloroform, iodoform, butyl chloride, probyl chloride, 1,1
- Dichloropropane, hexyl chloride, etc.

Quantitative Ratio The quantitative ratios of compounds (1) to (3) may be arbitrary as long as the effects of the present invention are recognized.

Generally, this quantitative ratio is determined based on the catalytic activity, the molecular weight distribution of the obtained polymer, the grinding conditions, etc., but it is preferably as follows.

The amount of magnesium halide relative to the total weight of the three components (1) to (3) is 1 to 98 weight percent, particularly preferably 50 to 95 weight percent, and the amount of halogenated silicon compound or halogenated carbon compound is 0.1 to 45% by weight, particularly preferably 0.5 to 20% by weight.

Mixing and Grinding The mixing and grinding of the three components (1) to (3) can be carried out in any grinding device that allows intimate contact between the three components.

Mixing and grinding should be carried out without contact with moisture or air, so as long as this point is taken into consideration, rotary ball mills, vibrating ball mills, impact mills, and various other mills can be used.

The degree of mixing and pulverization only needs to be sufficient to obtain a significant desired improvement effect compared to the case of simple mixing of the three components (1) to (3), and therefore, from this point of view, pulverization is It is sufficient to select the crushing time, crushing method, crushing conditions, etc.

These conditions are interrelated; for example, in a rotary ball mill, the desired catalyst composition can be obtained by combining various conditions such as ball filling rate, crushed sample filling rate, ball diameter, rotation speed, and crushing temperature. Although the required time varies, it is generally possible to obtain a product with sufficiently improved catalytic performance by grinding within 100 hours.

Those skilled in the art will be able to easily find the optimum combination of these grinding conditions.

If necessary, crushing can be carried out either wet or dry.

In a typical mixing and grinding method, three components (1) to (3) are ground in a mixed state from the beginning in terms of type and amount. It is also possible to add it sequentially or in portions over time.

(2) Component ■) Diolefin and formula AI as organic aluminum compounds
R3 (where R is a hydrogen atom or a hydrocarbon residue)
The ratio of the number of groups derived from diolefin to the number of R (hereinafter referred to as ``Ko'') is 0.
．． Use products that are within the range of 25-2.

AIR3 includes triethylaluminum, tri-n-
Butyl aluminum, triisobutyl aluminum,
Tri-n-hexylaluminum, diisobutylaluminum hydride, etc. are available, and particularly preferred results are obtained when triisobutylaluminum and diisobutylaluminum hydride are used.

Diolefins include isoprene, myrcene, 2-phenylbutadiene, phthalene, etc., and particularly preferred results are obtained when isoprene is used.

Therefore, a particularly preferred combination of diolefin and AIR3 is isoprene and triisobutylaluminum or diisobutylaluminum hydride.

The ratio of diolefin and AIR3 to be reacted varies depending on the desired molecular weight distribution, catalytic activity, etc., but is generally within the range of 0.25 to 2 in terms of (2) above.

As (R) increases, the molecular weight distribution becomes broader, but the catalytic activity decreases, so a range of 0.5 to 1.3 is particularly preferable.

Moreover, when R is 2 or more, the reaction product becomes a very viscous liquid or a substantially solid, which is difficult to handle and has the disadvantage that the catalytic activity is extremely reduced.

The reaction of the diolefin with the compound of the formula AIR3 can be carried out in a manner known per se, by heating under suitable conditions of temperature and reaction time depending on the nature of the desired reaction product.

Generally, the reaction temperature is 50-150℃, and the reaction time is 1 hour or more.
It is preferable to carry out the reaction for 10 hours.

Further, it is preferable that one of the reactants is continuously introduced in a fixed amount during the reaction time to cause the reaction.

Quantitative ratio The quantitative ratio of component (■) and component (2) is essentially the same as the quantitative ratio when component (2) is ordinary titanium trichloride.

Depending on this quantitative ratio, slight differences in catalytic performance such as changes in catalytic activity may be observed, but in general it can be used within the following range.

Component n)/Component I) = 0.1 to 100, preferably 1 to
50 (weight ratio).

(3) It can be carried out in a manner essentially not different from that in the case where the catalyst preparation component (1) is ordinary titanium trichloride.

For example, there is a method in which component I) and component (■) are directly fed separately into a polymerization vessel and the catalyst is formed simultaneously with the progress of polymerization, or a method in which component (I) and component (■) are mixed in advance in a polymerization solvent to form a catalyst. There is a method of forming the polymer and then feeding it into a polymerization vessel.

It is known that various modifications can be made to Ziegler's catalyst, but in this invention, as long as the spirit thereof is not unduly impaired, component I), ), heating, aging, washing,
Alternatively, desired modifications can be made, such as adding components other than components 1) and II) that improve catalyst performance, or performing other post-treatments.

2. The method of the present invention is essentially the same as the method for producing this type of ethylene polymer, except that the ethylene polymerization catalyst is as described above.

The catalyst of the present invention is of course applicable to ordinary slurry polymerization, but also to solvent-free polymerization which does not substantially use a solvent.

It can be applied to continuous polymerization, batch polymerization, or prepolymerization.

As the polymerization solvent in the case of slurry polymerization, saturated aliphatic or aromatic carbide groups such as hexane, heptane, cyclohexane, benzene, and toluene are used alone or in mixtures.

The polymerization temperature is about 110°C from room temperature, preferably 50°C.
~100°C.

In catalysts, polymerization temperature dependence on molecular weight distribution is observed.

In other words, the lower the polymerization temperature, the broader the molecular weight distribution.

This effect is unexpected and is cited as one of the features of the present invention.

Therefore, from this point of view, the polymerization temperature is particularly preferably between 60 and 80°C.

For example, hydrogen can be used as the molecular weight regulator.

Although the production of polyethylene by homopolymerization of ethylene is one representative embodiment of the process of this invention, monomers copolymerizable with ethylene, such as propylene, butene-1, hexene, etc. The present invention also covers a method for producing an ethylene copolymer containing α to olefins such as -1 up to a weight factor of about 10.

3 Experimental Examples Example-1 (1) Production of component I) 1.5 mm in a stainless steel pot with an internal volume of 370 ml
A stainless steel ball of diameter 43% was filled with an apparent volume of 1.9 g of titanium trichloride (T iCl3 (T)), 18.1 g of anhydrous magnesium chloride, and 2.9 g of silicon tetrachloride.
g was sealed in a nitrogen gas atmosphere and milled for 48 hours using a rotary pole mill (rotation speed: 128 rpm).

After the grinding was completed, the mixed and ground solid composition was taken out from the mill in a dry box and stored in a sample bottle purged with nitrogen gas.

(2) Production of component
The temperature was raised to 00°C.

Then 285 ml of isoprene was fed over 3 hours.

As a result, a colorless and transparent liquid was obtained.

Residual isoprene was removed, cooled to room temperature, and stored.

As a result of analyzing the product, the aluminum content was 14.3
The density was 0.908 at room temperature.

Further, as a result of gas chromatography analysis, the total value of the product was 1.22.

(3) Polymerization of ethylene In a nitrogen atmosphere, 500 ml of dry and degassed heptane was placed in a Widmer apparatus with an internal volume of 500 ml, and 0.05 g of the solid composition (component I) obtained in (1) above was added to the Widmer apparatus with an internal volume of 500 ml. 0.5 g of the obtained organoaluminum compound (component II)
A catalyst slurry was prepared by adding [component n)/component I)
=10 (weight ratio)].

After repeating vacuum-ethylene substitution several times into a tempered glass autoclave with an internal volume of 1 liter and equipped with a stirring and temperature control device, the catalyst slurry was introduced from the above-mentioned Widmer device under an ethylene atmosphere.

Polymerization temperature: 70°C, ethylene partial pressure: 3. 6kg/cm2,
Hydrogen partial pressure5. Polymerization was carried out at a rate of 4 kg/ant and a polymerization time of 3 hours.

These were kept under the same conditions during the polymerization.

However, the pressure, which decreased as the polymerization progressed, was kept constant by additionally introducing only ethylene.

After the polymerization was completed, ethylene and hydrogen gas were purged and the contents were taken out from the autoclave, and the polymer slurry was filtered and dried in a vacuum dryer at 70°C for 24 hours to obtain a 133I polymer.

Co(7) polymer ASTM-D 1 2 3 8-6
Melt index of 2.16 kg and 10.0 kg at 190°C (respectively M
, M■10), MI2=020, MI
10=3.8.

PR value (MI1o / MI2
) was 19.0.

Examples-2 to 3 Same conditions as Example-1 except that the polymerization temperature was set to 80°C (Example 2) or 60°C (Example 3) in order to clarify the effect of polymerization temperature on molecular weight distribution. Polymerization was carried out using

The results are shown in Table I together with the results of Example 1.

As can be seen from these results, it can be seen that the molecular weight distribution becomes broader as the polymerization temperature decreases.

Comparative Example-1 Mg(
OH). CI was prepared and supported with T iC 14 to obtain a solid with a titanium content of 12.07 Q/g of support.

This solid 100 ~ and the component (n) used in Example-1
Polymerization was carried out under the same conditions as in Example 1 except that 0.05 g of the polymer was used, and 80 g of polymer was obtained.

The M2 and MI10 of this polymer were measured and found to be 1.5 and 20.4, respectively, and the FR value was 13.6.

Comparative Examples 2 to 4 In the preparation of component (1), the amount of isoprene supplied was changed so that the ratio (2) of the number of groups derived from diolefin to the number of H became 0, 0.16, and 2.4. A catalyst was prepared under the same conditions as in Example 1, except that the organoaluminum compound prepared above was used, and ethylene was polymerized.

The results are shown in Table 1-2 together with the results of Example-1.

Example-4 In the production of component 1) of Example-1, T t C l s (T) was replaced by T iC 13 (A).
Component I) was produced in exactly the same manner except that ethylene was polymerized, and 155 g of polymer was obtained.

MI2 and MI10 were 0.16 and 3.0, respectively, and the FR value was 18.7.

Examples 5 to 7 Component ① was produced by changing the reaction ratio of isoprene and TiBA, and the other conditions were the same as in Example 1.

The results are shown in Table 3. Example 8 Except for using CCI4 instead of SiC 14 in the production of component I) of Example 1.
Component I) was prepared in the same manner, and ethylene was also polymerized.

138 g of polymer was obtained, and M 2 and 9 were each 0.
25, 4.65, and the FR value was 18.6.

Example 9 Ethylene polymerization was carried out in the same manner as in Example 1 except that 2% by weight of propylene was supplied relative to ethylene.

155 g of polymer was obtained, with M2 and MI10 of 0.35 and 6.30, respectively, and an FR value of 18.0.

Claims (1)

[Claims] 1. A method for producing an ethylene polymer, which comprises polymerizing ethylene by bringing it into contact with a catalyst consisting of a combination of the following components (1) and (2). (2) A solid composition obtained by mixing and pulverizing the following components (1) to (3). (1) titanium trichloride, (2) a halide of magnesium, and (3) a halogenated silicon compound or a halogenated carbon compound S iXnR4 -n. CXnR4 -n (where X is a halogen atom, R is a hydrogen atom and a hydrocarbon residue,
n represents an integer of 1 to 4. )■) An organoaluminum compound which is a reaction product of a diolefin and a compound represented by the following general formula, and in which the ratio of the number of groups derived from the diolefin to the number of R is in the range of 0.25 to 2. AIR3 (Here, R represents a hydrogen atom or a hydrocarbon residue.)