JPS6055046A - Propylene copolymer composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. suitable for use as a material for the production of packaging films, by blending two specified kinds of propylene random copolymers. CONSTITUTION:A resin compsn. consists of 98-45wt% propylene/ethylene random copolymer having an ethylene content of 0.3-6wt% and 2-55wt% propylene/butene-1 random copolymer having a butene-1 content of 0.3-15wt%. Said resin compsn. is excellent in transparency and is firm as well as having good low-temperature impact resistance and low-temperature heat-sealing characteristics and the above characteristics are well-balanced.

Description

[Detailed description of the invention] The present invention relates to propylene copolymer compositions.

Although propylene homopolymer film has advantages such as excellent transparency and strong stiffness, it has disadvantages such as low low-temperature impact strength and high heat sealing temperature.

Propylene is a film that improves these drawbacks.
An ethylene random composite film has been proposed, but although the low-temperature impact strength of this film has been improved, the high heat-sealing temperature has not been sufficiently improved. In order to lower the heat-sealing temperature, a large amount of ethylene may be copolymerized, but in this case, the generation of by-products is unavoidable, and this is not preferred as an industrial production method. Furthermore, a propylene-butene-1 random copolymer film using butene-1 instead of ethylene is also known, but this film has low low-temperature impact strength and requires extensive copolymerization of butene-1. This has the disadvantage that the resulting copolymer becomes soft and the film becomes stiff.

In addition, consumer demands for polypropylene films have become increasingly sophisticated, and therefore, evaluations of film physical properties for polypropylene films have become extremely strict. For example, if the heat-sealing temperature can be improved but the tensile modulus and low-temperature impact strength are inferior, the film will be rejected in terms of comprehensive evaluation.

In view of these circumstances, the present inventors conducted research to develop a resin composition that possesses one of the advantages of propylene homopolymer and eliminates the disadvantages of this polymer. Propylene-ethylene random copolymer,'
We have discovered that a resin composition obtained by polymerizing a propylene-butene-1 random copolymer with a constant v constant at a predetermined ratio satisfies the above object, and based on this knowledge, we have completed the present invention. be.

Invention It, propylene-ethylene random copolymer (ethylene-containing iiO, 3 to 6.11jjNd%) 9
8-45 weight percent and propylene-butene-1 random copolymer (butene-1 content gradient, 0.5-15 weight percent) 2-5
This is a propylene copolymer composition containing 5% by weight or more.

The propylene-ethylene random copolymer used in the present invention preferably has an ethylene content of a, S to 6.0% by weight.
tj: o, s~4. It is necessary that the amount is o weight ni%. Ethylene-containing T I? When t is less than 0.3% by weight, the low-temperature impact strength is insufficient, and (S, []weight i
If it exceeds t%, the film will be made fat Silc '46
If this happens, your back will become weak.

Next, the propylene-butene-1 random copolymer has a butene-1 content of 0.5 to 15% by weight, preferably 0.6%.
~10% by weight is required.

If the butene-1 content is less than 0.3% by weight, the effect of improving heat sealing properties will be insufficient, and if it exceeds 15% by weight, the stiffness will decrease when the film is produced. However, a large amount of expensive butene-1 is used, which is not economical.

All of the above copolymers can be produced by conventional methods, such as slurry polymerization, solution polymerization, gas phase polymerization, etc. using Zieglernack catalysts, supported titanium catalysts, etc. t￥j Kaisho 53-799
No. 84, No. 55-9051 * No. 55-98210, No. 56-22307 1% Kosho No. 46-51478, No. 4
9-1t543, etc.).

The propylene copolymer composition of the present invention comprises 98-45% by weight, preferably 95-50% by weight of propylene-ethylene random copolymer and 2-55% by weight, preferably 5% by weight of propylene-butene-1 random copolymer. ~50% by weight. If the amount of the propylene-ethylene random copolymer exceeds 98% by weight, the effect of improving low-temperature heat sealability will be insufficient, and if it is less than 45% by weight, the low-temperature impact strength will be insufficient and the film will If manufactured, the strength of the waist will be insufficient.

These copolymers may be blended by a known method, such as a combined dry/wet/melt blending method, a multi-stage melt blending method, a simple melt blending method, etc.

The kneading may be carried out using an extruder, a twin-screw kneading extruder, or the like. The resulting formulation can be made into a film using known film-forming machines.

The propylene copolymer composition of the present invention has excellent transparency,
In addition to being strong, it has good low-temperature impact strength and thermostatic heat-sealing properties, and has a good balance between the two, making it extremely useful as a material for packaging films.

Next, the present invention will be explained in detail with reference to examples.

Production example (1) Propylene-butene-1 random copolymer 8 tons of n-hebutane,
1.21 parts of titanium trichloride and 6.0 parts of diethylaluminum chloride were charged. Next, the temperature is 60°C and the pressure is 6.0kl? Polymerization was carried out by supplying a mixed gas of propylene and butene-1 under an atmosphere of /crl aO. Butene-1
was supplied in a constant amount at a time so that the composition within the polymerization system remained constant, and the internal pressure was controlled to be 6.0 kg/dG.

After the polymerization reaction is complete, add 100% n-butanol to the polymerization slurry.
1 was added to decompose the catalyst, the solvent-soluble components were separated and removed, and the resulting powder was dried.

(2) Propylene-ethylene random copolymer (11) except that ethylene was supplied instead of butene-1.
I did the same thing.

Examples 1 to 6 and Comparative Examples 1 to 6 Propylene-ethylene random copolymer and toflopylene-butene-1 random copolymer were each blended in predetermined amounts and extruded from an extruder to obtain pellets. Next, 3
A film with a thickness of 50 μm was produced using a 5-inch film forming machine.

The physical properties of the obtained film were measured 17 times.
Shown in the table. The tensile modulus in the table indicates the stiffness of the film,
(Film impact) This shows the IJ impact strength.

/ @1 Tensile 5Ll'J=I Based on JIs-z1yo2 ・2 Heat sealing temperature Using a heat sealer, the width 25 obtained by applying a load of 2 kg/CII to each other at the specified temperature and pressing them together for 2 seconds The fermentation sample was peeled at a peeling speed of 200 w/min and a peeling angle of 180°, and the temperature when the peeling resistance was 3ooy/25cm was determined. The ring-shaped film was punched out using a pendulum with an inch impact head, and the energy required for punching was measured. The equipment used is Toyo Seiki Seisakusho Film In/9 Tester.

Patent applicant: Idemitsu Petrochemical Co., Ltd. 9-

Claims (1)

[Claims] 1. Purpyrene-ethylene random co-merge (ethylene content 0.3-6.0 wt j1%) 98-45 wt.
and propylene-butene-1 random copolymer (butene-1)
Propylene copolymer composition containing 0.5 to 15% by weight) and 2 to 55% by weight