JPS5825693B2 - Polypropylene plant - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to polypropylene compositions with improved transparency, impact resistance and low temperature embrittlement.

Polypropylene is used in a wide range of applications because it has excellent mechanical properties, transparency, chemical resistance, and processability.

However, polymers made of polypropylene alone have the drawback of poor impact resistance and low-temperature embrittlement.

Many methods have been proposed to overcome these drawbacks of polypropylene, such as adding a small amount of ethylene or other α-olefins to propylene and copolymerizing it, or adding other resins to polypropylene. Attempts have been made to do so.

However, the copolymerization method has the drawbacks that first, the production of the copolymer results in a decrease in the production capacity of the polymer, and that the resin becomes flexible, resulting in a lack of rigidity.

Methods of blending other resins include, for example, a method of adding polyethylene (Japanese Patent Publication No. 37-6975), a method of adding an ethylene-propylene random copolymer (Japanese Patent Publication No. 35-1976),
7088), method of simultaneously adding ethylene-propylene random copolymer and polyethylene (Japanese Patent Publication No. 39-18
746) etc. are known.

Also, ethylene with an ethylene content of 75 to 30 moles
A method of mixing a 1-butene random copolymer with polypropylene immediately after polymerization (Japanese Patent Publication No. 38-7240) and an ethylene-
Method of blending 1-butene block copolymer (Special Publication No. 4)
3-24526) is also known.

However, all of these methods have problems such as improving the impact resistance and low-temperature embrittlement, but reducing the transparency of propylene or the mechanical strength of the resin.

An object of the present invention is to provide a polypropylene composition with improved transparency, impact resistance, and low-temperature embrittlement without impairing the chemical resistance and mechanical properties that are the characteristics of polypropylene. They have discovered that the objects of the present invention can be achieved by simultaneously blending a specific ethylene-1-butene random copolymer and low density polyethylene with polypropylene.

That is, the present invention provides (a) polypropylene 70 to 9
Ethylene-1-butene random having an ethylene content of 85 to 95 molar and a density of 0.86 to 0.92 g/i polymerized by a catalyst system consisting of (b) a soluble vanadium compound and an organoaluminum compound; This is a polypropylene composition comprising 15 to 1 weight part of a copolymer and (c) 15 to 1 weight part of low density polyethylene.

The polypropylene used in the present invention refers to crystalline polypropylene, including homopolymers of propylene and copolymers of propylene with other α-olefins such as ethylene and -butene in a molar proportion of 10 or less, preferably 7 or less. Including coalescence.

Preferred melt index of polypropylene (AST
M-D-1238-65,230°C) is in the range of 0.1 to 30; if it is less than 0.1, the moldability of the composition will be impaired, and if it is more than 30, the strength will be reduced.

Ethylene blended into polypropylene in the composition of the present invention
The 1-butene random copolymer is obtained by polymerizing ethylene in the presence of 1-butene using a catalyst system consisting of a soluble vanadium compound and an organoaluminium compound, and has an ethylene content of 85 to 95 moles; Density 0.86-0.92g Melt index 0.1-30
A polymer of

Examples of the soluble vanadium compound used in the polymerization catalyst include vanadium tetrachloride, vanadium oxytrichloride, vanadium triacetylacetonate, and oxyvanadium triacetylacetonate.

Examples of organic aluminum compounds that constitute the polymerization catalyst in combination with soluble vanadium compounds include ethylaluminum dichloride, diethylaluminum monochloride, ethylaluminum sesquichloride, diethylaluminum monopromide, butylaluminum monochloride, isobutylaluminum dichloride, isobutyl Examples include aluminum sesquichloride.

The polymerization can be carried out in a dispersion state, a suspension state, or an intermediate region between the two, and even in the case of a dispersion state, it is preferable to use an inert solvent as the reaction medium.

The solvent used in the polymerization is an aliphatic hydrocarbon having about 3 to 12 carbon atoms, such as propane, butane, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, kerosene or hydrogen halides, such as methyl chloride, Ethyl chloride, ethylene dichloride, etc. can be used alone or in combination.

The polymerization temperature is usually 0 to 100°C.

During the polymerization, an ethylene-1-butene copolymer having the properties described above can be obtained by adjusting the supply ratio of ethylene and 1-butene and appropriately using a molecular weight regulator such as hydrogen.

The ethylene-1-butene random copolymer used in the present invention needs to have an ethylene content in the range of 85 to 95 moles, preferably 87 to 93 moles.

If the ethylene content is less than 85 mol, the strength and chemical resistance of the composition will decrease, and if it is more than 95 mol, the effect of improving impact resistance will be poor, and the transparency of the composition will be reduced.

The density of the copolymer is determined from the ethylene content, but 0
．． 86 to 0.92 g/ci, preferably 0.88
to 0.91 g/crd can be used.

Melt index of ethylene-1-butene copolymer (
190°C) is preferably in the range of 0.1 to 30, preferably 0.3 to 20.

If it is less than 0.1, the moldability of the composition will be reduced and the compatibility with polypropylene will be reduced.

On the other hand, if it is 30 or more, the impact resistance and mechanical properties are reduced.

The low-density polyethylene that is blended with the polypropylene together with the ethylene-1-butene random copolymer in the composition of the present invention is obtained by radical polymerization under high pressure, usually about 500 to 1500 atm, and has a density of 0.9 i/i or less. polyethylene.

The melt index of the low density polyethylene is also preferably in the range of 0.1 to 30 from the viewpoint of compatibility.

The feature of the present invention is that an ethylene-1-butene random copolymer having an ethylene content of 85 to 95 moles, which was conventionally thought to have a poor impact resistance improvement effect, and low-density polyethylene are simultaneously blended into polypropylene. According to
As shown in the examples below, the transparency improvement effect is superior to when each is blended alone or when an ethylene-propylene random copolymer is used instead of an ethylene-1-butene random copolymer. Another advantage is that impact resistance can be significantly improved even though the mechanical strength is hardly lower than that of polypropylene alone.

The amount of the ethylene-1-butene random copolymer and low density polyethylene in the polypropylene composition of the present invention is 1 to 15 parts by weight, preferably 3 to 12 parts by weight, per 100 parts by weight of the composition.

If each part is less than 1 part by weight, the synergistic effect will be poor, and if it is more than 15 parts by weight, the mechanical strength and chemical resistance, which are characteristics of polypropylene, will be impaired, which is not preferable.

---1 The composition of the present invention may further contain a heat stabilizer, an ultraviolet absorber, a lubricant, a nucleating agent, an antistatic agent, a slip agent, an antiblocking agent, a dye, and the like.

The composition of the present invention can be prepared by combining any known mixer, such as a V-type flender, ribbon blender, Henschel mixer, etc., and a mixer, such as a conventional extruder, calender roll, Banbury mixer, etc.

The polypropylene composition of the present invention has transparency, impact resistance,
It has good low-temperature embrittlement properties, does not whiten even when bent, and maintains the good mechanical properties and chemical resistance that are inherent to polypropylene, so it can be used in any application where polypropylene can be used. However, it is especially advantageous in fields where transparency and impact resistance are required, such as food color clothing films, sheets, blow molding materials, etc.

The composition of the present invention can also be suitably used in applications in which it is laminated with a resin having good transparency such as nylon or polyester film.

Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these examples unless it exceeds the gist thereof.

Example 1 Propylene-ethylene random copolymer (melt index 0.6, ethylene content f5.5 mol%: 90 parts by weight, in a polymerization vessel using vanadium oxytrichloride and ethylaluminum sekichloride as polymerization catalysts, polymerization solvent hexane A mixed gas of ethylene and 1-butene (91 mol% ethylene, 11 mol% 1-butene) and hydrogen gas were supplied into the
Ethylene-1-butene random copolymer obtained by continuous polymerization under conditions of 0°C, 13°Cm, and residence time of 1 hour (melt index 3.5, ethylene content 92 mol%, density 0.90j! /d) 5 parts by weight and 5 parts by weight of low density polyethylene (trade name Mirason M-141, manufactured by Mitsui Polychemicals, melt index 0.9, density 0.91/i) were mixed for 3 minutes with a Henschel mixer, and then 65 ynmφ The mixture was granulated using an extruder at a resin temperature of 255° C. to prepare a polypropylene composition.

Next, using the above pellets, a blow molding machine was used to reduce the resin temperature to 2.
A cylindrical bottle with a basis weight of 1i of 400 CC% was molded at 20°C.

This cylindrical bottle was filled with water at 0°C and a drop test was conducted to measure the impact strength.

In addition, the evaluation was made by dropping the bottle on concrete and giving it a score of 10.
Fall height at which 5 of the books are destroyed: F5o)'J6 and 1m
Two methods were used: dropping the bottle repeatedly from a height of

In addition, a test piece was cut from the cylindrical bottle, and its tensile properties were determined using a Schopper type tester.

(Crosshead speed 50mi/m1rr) Optical properties were determined using Nihon Heavy Color Studio, ASTM-
It was determined by the method of D-1003.

Example 2 Example except that 85 parts by weight of the propylene-ethylene random copolymer used in Example 1, the ethylene-1-butene random copolymer, and low-density polyethylene were blended as shown in Table 1. This was done in the same manner as in step 1.

Example 3 Same as Example 1 except that the composition used in Example 1 was 85 parts by weight of propylene-ethylene random copolymer, 5 parts by weight of ethylene-1-butene random copolymer, and 10 parts by weight of low-density polyethylene. I went to

Example 4 Propylene homopolymer (melt index 0.8) 8
The same procedure as in Example 1 was conducted except that the composition was 5 parts by weight, 5 parts by weight of the ethylene-1-butene random copolymer used in Example 1, and 10 parts by weight of low-density polyethylene.

Example 5 85 parts by weight of the propylene-ethylene random copolymer used in Example 1, low density polyethylene i.

parts by weight, vanadium tetrachloride and ethylaluminum sesquichloride as polymerization catalysts, and the mixing ratio of ethylene and 1-butene (88 mol% ethylene, 12 mol% 1-butene).
Ethylene-1-butene random copolymer (melt index 2.5, ethylene content 88 mol%, density 0.88.!) obtained in the same manner as in Example 1 except that
The test was carried out in the same manner as in Example 1 except that the composition was 5 parts by weight of i'/i).

The evaluation results of Examples 1 to 5 are shown in Table 1. Comparative Examples 1 and 2 A 400cc cylindrical bottle was molded from the propylene homopolymer used in the example and the propylene-ethylene random polymer. It was tested in the same manner.

Comparative Example 3 The same procedure as in Example 1 was carried out except that the composition used in Example 1 was 90 parts by weight of the propylene-ethylene random copolymer and 10 parts by weight of the ethylene-1-butene random copolymer.

Comparative Example 4 The same procedure as in Example 1 was conducted except that 90 parts by weight of the propylene-ethylene random copolymer used in Example 1 and 10 parts by weight of low-density polyethylene were used.

From Example 1 and Comparative Examples 3 and 4, the combination of ethylene-1-butene random copolymer or low-density polyethylene has a better balance of impact strength and tensile strength, and has better transparency than when added alone. The improvement is clear.

Comparative Example 5 Same composition as Example 1 except that ethylene-propylene random copolymer (melt index 0.7, ethylene content 65 mol%) was used instead of the ethylene-1-butene random copolymer of Example 1. It was tested using

Comparative Example 6 Same composition as Example 1 except that ethylene-propylene random copolymer (melt index 1.0, ethylene content 90 mol%) was used instead of the ethylene-1-butene random copolymer of Example 1. It was tested using

Comparative Examples 5 and 6 show that a molded article with good impact resistance and transparency like the composition of the present invention cannot be obtained with the ethylene-propylene random copolymer.

The evaluation results of Comparative Examples 1 to 6 are also listed in Table 1.

Claims (1)

[Claims] 1 (a) polypropylene 70 to 98 wt.; (b)
) Ethylene content 85 polymerized by a catalyst system consisting of a soluble vanadium compound and an organoaluminum compound
95 molar ratio, density 0.86 to 0.92 g/d
Ethylene-1-butene random copolymer 15 to 1
Weight factor, and (c) low density polyethylene 15 to 1
A polypropylene composition consisting of a weight factor.