JPH02173139A - polypropylene composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a borigyopirene composition with good moldability and stretchability.

[Conventional techniques and problems]

Conventionally, sheets and films using polypropylene have been used as anti-polishing agents, anti-blocking agents, etc.
Charcoal 5 with an average particle diameter of 2 to 3 μm is used for stretching products such as bands and yarns to prevent warping and warping. Contains calcium.

By the way, when polypropylene with a narrow molecular weight distribution expressed by the ratio of weight average molecular weight to fine average molecular weight is used as polypropylene, transparency and gloss are improved in sheets and films, and stretchability is improved in bands and yarns. However, when extrusion molding is performed by blending calcium carbonate with an average particle size of 2μ or more into polypropylene with a narrow molecular weight distribution, calcium carbonate is deposited at the exit of the die, and this deposited calcium carbonate is deposited on the surface of the polypropylene sheet or film. It adheres to sheets and films, causing them to quickly lose their transparency and gloss, and in drawn products such as yarn, causing stretching breakage, which significantly impedes productivity. Such a phenomenon is not observed in polypropylene, which has a wide molecular weight distribution.

[Means to solve the problem]

As a result of intensive research to solve the above-mentioned problems regarding polypropylene with a narrow molecular weight distribution, the inventors of the present invention have found that by blending silicon dioxide in addition to the above-mentioned inorganic fillers such as calcium carbonate, the above-mentioned problems can be solved. The inventors have discovered that the problem can be solved, and have completed the present invention.

That is, the present invention provides polypropylene 100.0% having a ratio of weight average molecular weight to number average molecular weight of 75 or less. This is a polypropylene composition comprising 0.01 to 0.5 parts by weight of silicon dioxide and 0.1 to 10 parts by weight of other inorganic fillers.

The polypropylene used in the present invention is a single polymer of propylene; a block copolymer or a graft copolymer of 50 mol% or more of propylene and an α-olefin other than propylene such as ethylene, butene-1, pentene-1, etc. or a random copolymer; a mixture of one of these polymers; and a mixture of one of these polymers and a polymer of α-olefin other than propylene. The polypropylene used in the present invention has a molecular weight distribution expressed by the ratio of weight average molecular weight to number average molecular weight of 7.5 or less. In the present invention, even if the above-mentioned molecular weight distribution is 7.0 or less, the inorganic filler can be effectively prevented from being precipitated or deposited at the die outlet during molding by adding silicon dioxide, which will be described later.

Other components of the polypropylene compositions of the present invention are inorganic fillers. Although the average particle size of the inorganic filler is not particularly limited, even when an inorganic filler having a relatively large average particle size of 2 μm or more is used as described above, the present invention allows the inorganic filler to be transferred to the die outlet during extrusion molding. Precipitation and deposition of filler can be effectively prevented.

The type of inorganic filler is not particularly limited as long as it is other than silicon dioxide. For example, known inorganic fillers that can be added to polypropylene are used depending on the purpose, such as lucium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, talc, and clay.

The blending amount of the inorganic filler is in the range of α1 to 10 parts by weight, preferably 0.5 to 8]1 part by weight, based on 100 parts by weight of polypropylene. If the amount is less than the above lower limit, the filling effect of the inorganic filler, i.e., matting, anti-blocking, etc. Even if silicon is added,
It is not possible to prevent the inorganic filler from precipitating and depositing at the die outlet during molding.

Another component of the polypropylene composition of the present invention is silicon dioxide. The average particle size of silicon dioxide is 3 μm or less, preferably 0.1 μm or less, in order to prevent precipitation of the inorganic filler.
It is preferable that it is in the range of ~1.5 μm. Silicon dioxide may be either crystalline or amorphous. The amount of silicon dioxide blended is 0 per 100 parts by weight of polypropylene.
．． The range is from 0.01 to 0.5111 parts, preferably from 0.1 to 0.01 parts.
The range is 3. If the blending amount is less than 0.011L11 parts, there is no effect of preventing the precipitation of the inorganic filler described above, and if it exceeds 0.5 parts by weight, the surface condition such as gloss of the molded product of the polypropylene composition may be affected. Undesirable because of its negative effects.

Polypropylene group # of the present invention: Additives that are commonly used within the range that do not impede the effects of the present invention, such as
Antioxidants, dispersants, lubricants, colorants, etc. may be added.

〔effect〕

According to the present invention, it is possible to prevent the inorganic filler from being deposited and deposited at the die outlet during extrusion molding. For this reason, the inorganic filler precipitated at the die exit will not adhere to the surface of the polypropylene molded product, thereby preventing deterioration of the transparency and gloss of the polypropylene molded product, and will not cause stretching breakage in the case of stretched products. Not at all.

〔Example〕

The present invention will be explained below with reference to Examples and Comparative Examples.
The present invention is not limited to these examples.

In addition, the molecular weight distribution of polypropylene in Examples and Comparative Examples is the ratio of the weight average molecular wall to the number average molecular wall measured using gel permeation chromatography, and the measurement conditions are as follows. be.

Equipment GPC1500 type column manufactured by Waters GMH6-HT manufactured by Tosoh Measuring temperature 135°C Solvent O-dichlorobenzene The precipitation of the inorganic filler at the die outlet was evaluated visually according to the following criteria.

1: Not precipitated at all 2: Slightly precipitated 3: Slightly large amount 4: Large amount 5: Very large amount Examples 1 to 5 and Comparative Examples 1 to 4 Polypropylene blended with calcium carbonate and silicon disulfide shown in Table-1 Using an extruder (50tm960), melt-extrude it into a film at 230''C with a heat roller die with a die lip of 0.8m, cool and solidify it while taking it off at 15@/m to make a polypropylene film, and then turn the film into a tape. Cut and open stretch at 130℃
The tape was stretched 7 times to produce a 900 denier stretched polypropylene tape.

The amount of carbonated power runum is all polypropylene 100%.
It is 21 parts by weight.

Examples 6 to 8 and Comparative Examples 5 to 7 Polypropylene containing calcium carbonate and silicon dioxide shown in Table 2 was extruded at 240°C using a 4011 m5 extruder and a T-die with a die lip of 0.8. A sheet with a thickness of 0.5 fin was formed while taking it off at 2y17m.

At this time, the precipitation of calcium carbonate at the die outlet was observed. All formulators of calcium carbonate are 5 parts by weight per 1 part of 100mj of polypropylene.

Examples 9 to 12 1 part by weight of the inorganic filler shown in Table 3 and 0.0 parts by weight of silicon dioxide were added to 1001 parts of polypropylene having a molecular weight distribution of 65.
1 part by weight was blended, and a sheet was molded using an extruder in the same manner as in Examples 6 to 8. The results are shown in Table-3.

Manual continuation supplementary book (method) %formula% Display of incidents % Gansho 63-32801, name of invention Boria 0 pyrene composition person who makes corrections Relationship to the case Patent applicant Address: 1-1 Mikage-cho, Tokuyama City, Yamaguchi Prefecture issue Date of amendment order March 13, 1999 Same shipping date March 28, 1999 32′t

Claims (1)

[Claims] (1) 100 parts by weight of polypropylene with a ratio of weight average molecular weight to number average molecular weight of 7.5 or less, 0 parts of silicon dioxide
．． 01-0.5 parts by weight and other inorganic fillers 0.1-10
A polypropylene composition consisting of parts by weight.