JPH01203444A - Propylene copolymer composition and production thereof - Google Patents

Abstract

PURPOSE:To obtain the present composition, excellent in rigidity and impact resistance and hardly whitening in impact, by initially copolymerizing a mixture of propylen with butene and then a mixture of propylene with ethylene in respective specific proportions in the presence of a stereoregular catalyst. CONSTITUTION:The aimed composition obtained by copolymerizing a mixture of propylene and butene with 0.5-10wt.% butene content in an amount within the range of 70-95wt.% based on the total amount of polymerization in the first stage and then a mixture of propylene and ethylene with 20-80wt.% ethylene content in an amount within the range of 5-30wt.% in the second stage both in the presence of a stereoregular catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a propylene copolymer composition and a method for producing the same. For more details, see High Rigidity.

The present invention relates to a propylene copolymer composition that has excellent impact resistance, particularly impact strength at low temperatures, and is resistant to whitening upon impact, and a method for producing the same.

[Conventional technology]

Propylene polymers have excellent physical properties such as rigidity and heat resistance, and are used in a wide range of fields. Among these, it is a propylene polymer that has improved impact resistance while maintaining the high rigidity that is the original property of polypropylene. Ethylene-globylene-pronoc copolymers are widely used in the injection molding field.

However, this ethylene-brobylene broth copolymer has the following drawbacks.

That is, the disadvantage is that the affected areas easily turn white due to impact force or bending force, which significantly reduces the commercial value.

As a method for improving such drawbacks of the above-mentioned ethylene-propylene block copolymer.

Various proposals have been made in the past, including one example.

Method of blending polyethylene with ethylene-propylene block copolymer (JP-A-55-3g2'l!;
same! ! -IO'133J 11th jA-36333
, 62-7t19sO, etc.) - In the multistage polymerization of propylene and ethylene, propylene containing a small amount of ethylene is polymerized in the first step, and ethylene and propylene are copolymerized in the second and subsequent steps to produce ethylene-propylene. Method for obtaining block copolymers (t\j Kaisho 33
-gg0'19. same! ;'l-/391,9. :1 +
6θ-2g'l//-6o-946/2, etc.).

However, the effect of improving the whitening resistance of the block copolymer obtained in the former case is still not sufficient, and the effect of improving the whitening resistance of the block copolymer obtained in the latter case is still insufficient.

Although the effect of improving whitening resistance is recognized, it has the disadvantage that the rigidity, which is an inherent property of polypropylene, is impaired. A propylene polymer with excellent rigidity, impact resistance, and whitening resistance has not yet been obtained.

[Problem that the invention seeks to solve]

The object of the present invention is to obtain a propylene copolymer composition that is excellent in all three properties of rigidity, impact resistance, and whitening resistance and is well-balanced.

[Means for solving problems]

As a result of intensive studies to achieve the above object, the present inventors have found that a propylene copolymer composition mainly consisting of a propylene-butene copolymer and a propylene-ethylene copolymer has excellent rigidity and impact resistance. It has excellent impact strength at low temperatures and whitening resistance, and is polymerized in at least two stages in the presence of a stereoregular catalyst.

That is, they found that a propylene copolymer composition obtained by copolymerizing a propylene-butene mixture in the first stage and a propylene-ethylene mixture in the second stage had the above characteristics, and completed the present invention. I came to the conclusion.

That is, the present invention has a butene content O, S~/Q weight t%.
a propylene copolymer composition comprising 70 to 95% by weight of a propylene-butene copolymer, and 30 to 7% by weight of a propylene-ethylene copolymer having an ethylene content of co-o-go weight%;

A method for producing propylene copolymer compositions by at least λ stage polymerization in the presence of a stereoregular catalyst, in which a monopropylene-butene mixture with a butene content of O, S to IO wt % is provided in the first stage.

Copolymerize in the range of 7θ to 95% by weight of the total polymerization amount, and
In the step, a propylene-ethylene mixture having an ethylene content of 20-K0 weight is copolymerized in a range of S to 30% by weight of the total polymerization amount. The present invention relates to a method for producing a propylene block copolymer.

The present invention will be explained in detail below.

The propylene copolymer composition of the present invention comprises a propylene-butene copolymer and a glopylene-ethylene copolymer. These copolymers are.

propylene and butene using stereoregular catalysts.

Alternatively, it can be produced by copolymerizing propylene and ethylene.

The polymerization catalyst used in the present invention is composed of a titanium-containing solid catalyst component and an organoaluminum compound, and I#
The catalyst is not limited to, and any known catalyst can be used.

As the titanium-containing solid catalyst component, known carrier-supported catalyst components containing solid magnesium compounds, titanium compounds, and halogens can also be used, but those containing titanium trichloride as the main component are preferably used.

As the material containing titanium trichloride as a main component, conventionally known titanium trichloride can be used. For example, titanium trichloride that has been activated by ball mill grinding; titanium trichloride that has been further solvent-extracted; beta-type titanium trichloride that has been treated with a complexing agent such as ethers, and further treated with titanium tetrachloride to produce aluminum Titanium trichloride whose atomic ratio to titanium is o, is or less; in the presence of ethers.

Examples include titanium trichloride, which is treated with an organoaluminum compound to form a liquid, which is further heated to form a solid, with an aluminum content of 0.15 or less in terms of atomic ratio to titanium.

Particularly preferred among these titanium trichlorides is one in which the aluminum content is 0.75 or less in terms of the atomic ratio of aluminum to titanium, preferably 0,/or less, and more preferably o, O or less.

And it contains a complexing agent.

The organoaluminum compound used as a cocatalyst for the titanium-containing solid catalyst component has the general formula -AtI(rlX
, -o (wherein R is a hydrocarbon group with carbon number/-2Q,
represents halogen, n represents the number of s, 3≧n>/)
It is a compound represented by

When the titanium-containing solid catalyst component is a carrier-supported catalyst component containing a solid magnesium compound, it is preferable to use -AtR, or a mixture of AtR, AtR, and X.

Also, if the titanium-containing solid catalyst component is mainly composed of titanium trichloride, AtR? It is preferable to use X, but
Especially diethylaluminum chloride, di-normal globyl aluminum chloride, diethyl aluminum chloride.

Di-normal octylaluminum chloride is preferred.

The titanium trichloride and organoaluminum compound shown above generally have a molar ratio of organoaluminium compound/titanium trichloride of 1 to 30. It is preferably used in the range of 0 to /S.

In the present invention, the above-mentioned catalyst may be used as is, but it is preferable to preliminarily polymerize a small amount of α-olefin onto the catalyst made of titanium trichloride and an organoaluminum compound as a pretreatment.

The above method uses an inert solvent 1 such as hexane.

Titanium trichloride and an organoaluminum compound are added to heptane, etc., and propylene, ethylene, butene-7
or a mixture thereof may be supplied for polymerization. This pretreatment is generally referred to as prepolymerization, and known polymerization conditions can be used as they are. The polymerization temperature is preferably 30 to 70°C.

The higher the polymerization rate per unit weight of titanium trichloride.

This is preferable from an equipment or economic point of view.

It is generally in the range of Q, /~1oof/P-TiC4. Furthermore, a molecular weight regulator 1 such as hydrogen may be added during prepolymerization. Furthermore, it is preferable that the prepolymerization is carried out uniformly in a batch manner. This prepolymerization is effective in improving polymer properties such as bulk density.

Furthermore, an additive for improving stereoregularity may be used as a third component in the catalyst made of titanium trichloride and an organoaluminum compound described above. For this purpose N, (
Various compounds containing lP or Si, and hydrocarbon compounds are used. The amount of the third component added is generally in the range of 0.000/-5 mol, preferably 0.00/-1 mol, per 7 mol of titanium trichloride.

The most significant feature of the present invention is that the butene content is 0.
5 to IQ weight % propylene-butene copolymer 70 to 9
5% by weight and 30-5% by weight of a propylene-ethylene cocharger with an ethylene content of 20-80% by weight. If the butene content of the globylene-butene copolymer component is less than O, S weight %, not only will the effect of improving low-temperature impact strength not be recognized, but the whitening resistance will also be insufficient. Moreover, if the butene content exceeds 70% by weight, the rigidity, which is an excellent property of polypropylene, will be impaired.

Regarding the propylene-ethylene copolymer component, if the ethylene content is less than 20% by weight or more than the go type weight, the impact resistance will be insufficient.

Moreover, when the amount of the propylene-ethylene copolymer component in the total weight is 5% by weight or less, it is resistant.

The composition of the present invention may contain additives such as a heat stabilizer, if necessary.

The composition of the invention can be obtained by various methods.

For example, it can be obtained by separately manufacturing the propylene-butene copolymer and propylene-ethylene copolymer and kneading them by a known method. For example, it can be prepared by combining a mixer such as a ribbon blender, a V-type blender, or a Henschel mixer with a common mixing machine such as a screw extruder, Banbury mixer, or roll.

Further, the copolymerization of propylene and butene and the copolymerization of propylene and ethylene are carried out by at least λ stage polymerization to produce a propylene block copolymer. So-called polymeric blending methods are also applicable. In that case, the polymerization is carried out using the catalyst system described above as follows.

That is, it is preferable to carry out propylene-butene copolymerization in the first stage polymerization, and then carry out glopylene-ethylene copolymerization in the second stage polymerization without deactivating the catalyst. These polymerizations can be carried out by known slurry polymerization using an inert hydrocarbon, slurry polymerization in liquefied propylene, gas phase polymerization, or a combination thereof.

These polymerization methods may be either a batch method or a continuous method.
The reaction conditions are /-/θO atm, preferably 5 to DaO atm, and the temperature is 50 to 90°C.

Preferably, the temperature is appropriately selected within the range of 60 to goC. For example, in the seventh step, propylene and butene are copolymerized in the presence of liquefied propylene, and then propylene and ethylene are copolymerized in the gas phase in the second step without deactivating the catalyst. , or the first stage.

There is a method in which the second stage is carried out in a gas phase. Of course, a more multi-stage method may also be used.

In the second stage polymerization, a propylene/ethylene mixture with an ethylene content of 20 to 80-vP@b is copolymerized by 5 to 30 parts (7%) of the total polymerization amount.In order to obtain a copolymer with such a composition. In this case, the monomer composition of the gas phase in one polymerization vessel may be 1Io to 90 mol of propylene.

Further, as a method for controlling the molecular weight of the produced polymer, a known molecular weight controlling agent such as hydrogen or diethylzinc may be appropriately added to the monopolymerization reaction.

〔Example〕

The present invention will be illustrated in more detail with reference to Examples and Comparative Examples below, but the present invention is not limited thereto unless it departs from the gist thereof.

Physical property values etc. were measured by the following methods.

O-butene content and ethylene content It was determined from a known infrared absorption spectrum.

Q Tensile yield point strength Measured in accordance with JIS K b7sg.

O impact strength (Izod) Measured in accordance with JIS K qllo. (With a notch, 23℃) O impact whitening At 23℃, using a DuPont impact tester, 301
rrlRφ A press-formed sheet with a thickness of 1 m is placed on the pedestal, a hemispherical striking core with a tip radius of z inches (t, 3 vatr) is brought into contact with it, and a weight of lkt is placed on it.
The product was dropped naturally from a height of 1,000 yen, an impact was applied, and the area was measured to determine the impact whitening property.

O embrittlement temperature Measured in accordance with JIS K 72/A.

Example 1 Prepylene-butene copolymer body TRS having a butene content of 6% by weight and 8% by weight and 75% by weight of a propylene-ethylene copolymer having an ethylene content of 60% by weight were mixed in a Henschel mixer and then mixed with a screw. The mixture was melt-kneaded using an extruder and then granulated using a pelletizer to obtain a propylene copolymer composition. The tensile yield point strength of this copolymer composition is 22
s (kf/ctd), Izod Impact strength is q
, 5ckti-(M/cm), embrittlement temperature is -20
C), and the impact whitening area was 2.6 (R).

Examples A) Preparation of solid titanium trichloride Purified toluene was charged into a flask having a volume of 1 liter, which was sufficiently purged with nitrogen at room temperature.

2 g, b P (θ, 2 jT mol) were added to obtain a brown homogeneous solution. Next, the temperature was raised to 70°C, and after 30 minutes, precipitation of purple fine granular solids was observed, but the temperature was maintained at 10°C for 12 hours. After further holding at 96°C for about 1 hour.

Separate the granular purple solid and wash with n-hexane to approx.
Solid titanium trichloride of e was obtained.

B) Production of propylene polymer-containing titanium trichloride (pretreatment) Purified n-hexane 250- was placed in a 500- flask that had been sufficiently purged with nitrogen, and 1.91 of diethyl aluminum chloride and the solid titanium chloride obtained in A) above were added. T i
Yu as Cl3, 5? After charging (0.0/4 mol), the temperature was kept at 0°C, and while stirring - propylene gas/2
．． Contact treatment was carried out by blowing 3 f into the gas phase for about io minutes.

Next, the solid components were allowed to settle and the supernatant liquid was removed by degantation and washed several times with n-hexane to obtain solid titanium trichloride containing a propylene polymer.

C) Preparation of propylene copolymer composition Diethylaluminum monochloride was added as a cocatalyst to an induction-stirred autoclave with a capacity of 1,000 liters purged with dry nitrogen.
, g rrmol, methyl methacrylate θ, θJ 2 mmol as the third component.

l-puf7/gf, water accumulation gas t, 2kg/ad.

7009- of liquefied propylene was charged. Raise the temperature of the autoclave until it reaches 70°C.

The propylene polymer-containing solid titanium trichloride obtained in step B) above was press-injected as +TiC1 at a pressure of 25 to 100% nitrogen to start a polymerization reaction.

After 3 hours, the unreacted propylene was immediately tapered off, and the combined powder was heated to 50°C under a purified nitrogen atmosphere. sampled.

Subsequently, hydrogen gas o, ogy/Crd was blown into this reactor, and when it reached goc, a propylene-ethylene mixed gas was supplied to change the gas composition of the gas phase to propylene/(
Propylene + ethylene) = A! mol %'-
The gas phase polymerization reaction was continued for 35 minutes at the goc while maintaining the pressure at t5kf/cr/lQ.

After the reaction is completed, unreacted monomer gas is purged, and the propylene block copolymer is heated to 320? Obtained.

0.0% of BHT (2,6-di-t-butyl-p-cresol) was added to the thus obtained polymer powder. /
After adding o, i weight% of Irganox 1010 (stabilizer manufactured by Nippon Ciba Geigy; trade name) and 0.1 weight% of calcium stearate and pelletizing using a screw extruder with an inner diameter of 208, Various physical properties were measured.

The butene content in the first stage of the obtained polymer was O, S weight %, the ethylene content in the second stage was 60 weight %, and the proportion in the total polymer was 12 weight %.

Moreover, the tensile yield point strength of the obtained copolymer composition was 2.
7.7 (kp/cr/l), Izod impact strength g, 3 (k, pm (M1/cm) - embrittlement impregnation 1/o (C).

The impact whitening area was +, g(7), indicating an excellent balance between rigidity and impact resistance, and improved impact whitening property.

Example 3 The same procedure as in Example 1 was carried out except that in Example C), the amount of 7-butene supplied was changed to 7701.

The butene content in the first stage of the obtained polymer was 6.5% by weight, the ethylene content in the second stage was 60% by weight, and the proportion in the total polymer was 11% by weight.

The tensile yield point strength is 22.7 (kr/cIi)
.

Izod impact strength is 7.1% (k, y-t, */c
ry+), embrittlement temperature - here (°C), and impact whitening area were 5 (cy+1), indicating an excellent balance between rigidity and impact resistance, and improved impact whitening property.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the propylene-butene copolymer in Example 1 was replaced with a propylene homopolymer.

The tensile yield point strength of the resulting composition was 110 (kIF
/Crl), Izod impact strength is g, s
(kg - Crn 7cm), the embrittlement temperature is ≠ (C
), ffi whitening area was 7.2 (c++).

Although it has an excellent balance of rigidity and impact resistance at room temperature, it has problems with impact strength and impact whitening resistance at low temperatures.

Comparative Example The same procedure as Example λ was carried out except that 1-butene was not supplied in Example 2-C).

The obtained polymer did not contain butene in the first stage, and the ethylene content in the second stage was 60% by weight.

The proportion in the total polymer was 13% by weight.

1I (C), impact whitening area is +, 0 (d).

The balance between rigidity and impact resistance, especially impact resistance at low temperatures, was poor, and impact whitening resistance was also problematic.

〔Effect of the invention〕

The propylene copolymer composition of the present invention has an excellent balance between rigidity and impact resistance, and has significantly improved impact whitening area.

Patent applicant: Mitsubishi Chemical Industries, Ltd. Representative Patent attorney required - 1 other person

Claims (2)

[Claims] (1) Propylene with a butene content of 0.5 to 10% by weight
Butene copolymer 70-95% by weight and ethylene content 20%
~80% by weight propylene-ethylene copolymer 30-5
A propylene copolymer composition consisting of % by weight. (2) In a method for producing a propylene copolymer composition by at least two stages of polymerization in the presence of a stereoregular catalyst, the first stage comprises a propylene-butene copolymer having a butene content of 0.5 to 10% by weight. The mixture is copolymerized in a range of 70 to 95% by weight of the total polymerization amount, and in the second stage, a propylene-ethylene mixture with an ethylene content of 20 to 80% by weight is copolymerized in a range of 5 to 30% by weight of the total polymerization amount. A method for producing a propylene copolymer composition, the method comprising: