JPH06287369A - Polypropylene composition - Google Patents

Abstract

PURPOSE:To provide the title composition which can give a noncolored molding containing a large amount of beta-crystals contributing to the improvement of properties by usual molding conditions or crystallization conditions. CONSTITUTION:The composition comprises 100 pts.wt. crystalline isotactic polypropylene and 0.1-10 pts.wt. aromatic hydrocarbon compound having at least three aromatic rings in the molecule.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene composition which is useful for producing various molded articles having non-coloring property and improved impact strength, and for producing roughened or porous sheets, films, fibers and the like. More specifically, the present invention relates to a polypropylene composition containing a specific aromatic hydrocarbon compound in order to exhibit the above characteristics on a molded article.

[0002]

2. Description of the Related Art Crystalline isotactic polypropylene includes α crystal (monoclinic system), β crystal (hexagonal system), γ crystal (triclinic system), and smectic crystal (pseudo hexagonal system). It is known to take a crystal transformation. Also, isotactic polypropylene usually takes the most stable α crystal, but β crystal is generated by high temperature crystallization under a temperature gradient, and a small amount of γ crystal is found in polypropylene with poor isotacticity. It is also known that smectic crystals are generated in cold-stretched products and rapidly solidified products.

Among the various crystal systems described above, isotactic polypropylene containing β crystal is, for example, that the impact strength of the molded product is improved, that the melting point of β crystal is low, By adding a value-added product such as roughened or porous film, sheet or fiber by stretching at a temperature between the melting points of α and β crystals and melting and sinking the β crystal portion, etc. From the viewpoint, a production technique of isotactic polypropylene containing a large amount of β crystal has attracted attention.

Generally, as a method for producing this type of isotactic polypropylene containing a large amount of β crystals, a method of crystallization at a high temperature under a temperature gradient or a method of adding quinacridone as a β crystal nucleating agent is known. .

[0005]

In the case of the above-mentioned conventional method, that is, the method of producing β crystal by high temperature crystallization under a temperature gradient, the under-crystal condition is limited to a narrow range and the under-crystallization time is limited. It is not a practical method because it takes a long time. Further, the method of adding quinacridone as a β crystal nucleating agent has a drawback that the product is colored red although the crystallization conditions are not limited.

The present invention is intended to overcome the above-mentioned conventional drawbacks. Therefore, the present inventors have made extensive studies on a β crystal nucleating agent that produces a large amount of β crystal under normal molding conditions or normal crystallization conditions and has few problems. As a result, by adding a specific aromatic hydrocarbon compound to isotactic polypropylene, it is possible to generate a large amount of β crystals under normal molding conditions or crystallization conditions. We have found that we can enjoy the benefits based on it.

[0007]

SUMMARY OF THE INVENTION In general terms, the present invention is directed to crystalline isotactic polypropylene 100.
The present invention relates to a polypropylene composition, characterized by containing 0.1 part by weight and 0.1 to 10 parts by weight of an aromatic hydrocarbon compound having 3 or more aromatic rings in one molecule. Hereinafter, the technical configuration of the present invention will be described in detail.

In the polypropylene composition of the present invention,
The polypropylene component is not particularly limited as long as it is crystalline isotactic polypropylene. The crystallinity of the crystalline isotactic polypropylene is not particularly limited. Usually, the crystallinity measured by X-ray diffraction is preferably 30% or more. The isotacticity of crystalline isotactic polypropylene is not particularly limited, but ¹³ C-NMR
It is preferable that the pentad fraction as measured by 0.80 or more. The crystalline isotactic polypropylene of the present invention includes not only a propylene homopolymer but also a random or block copolymer with an α-olefin as described later. For example, propylene / α-olefin. In the case of a random copolymer, the above ¹³
It may be difficult to measure isotacticity by C-NMR.

The crystalline isotactic polypropylene preferably used in the present invention is specifically exemplified as follows.
For example, propylene homopolymer, ethylene, butene-
1, pentene-1, hexene-1, 3-methylbutene-
Examples thereof include random and block copolymers of α-olefin such as 1,4-methylpentene-1 and propylene. In the case of the propylene-α-olefin random copolymer described above, the content of α-olefin is preferably 10% by weight or less from the viewpoint of crystallinity, and in the case of the propylene-α-olefin block copolymer, The content of α-olefin is 30 from the viewpoint of crystallinity.
It is preferably not more than weight%.

Next, in the polypropylene composition of the present invention, the aromatic hydrocarbon compound used as the β crystal nucleating agent, which is another important component, should have three or more aromatic rings in one molecule. If not, there is no particular limitation. As the above-mentioned aromatic ring, generally, an aromatic ring having 5 to 7 carbon atoms, or a ring hydrogenated thereto may be present independently in the molecule, or may be present in a condensed state. Good.

In the present invention, an aromatic hydrocarbon compound having three or more aromatic rings in one molecule which is preferably used in the present invention is exemplified by pyrene, o-terphenyl, m-terphenyl, p-terphenyl, Examples include anthracene, acenaphthene, fluorene, phenanthrene, fluoranthene, and pyrene. In the present invention, these aromatic hydrocarbon compounds may be used alone or in combination of two or more.

In the present invention, the amount of the aromatic hydrocarbon added may be determined in relation to the amount of β crystals produced. Generally, 0.1 to 10 parts by weight, preferably 0.3 to 10 parts by weight, based on 100 parts by weight of crystalline isotactic polypropylene.
3 parts by weight are used. That is, when the amount of the aromatic hydrocarbon compound added is less than 0.1 part by weight, the amount of β crystals produced is small, and when it exceeds 10 parts by weight, not only the amount of β crystals produced is reduced, but also the amount of aromatic hydrocarbon compound is reduced. The compound comes to bleed out on the surface of the molded article produced from the composition of the present invention, and it is not preferable from the viewpoint of cost.

As described above, the amount of the aromatic hydrocarbon compound used is set in relation to the amount of β crystals produced, and the amount of β crystals produced is generally represented by a K value. In the present invention, the content of β-crystals in polypropylene generally depends on the amount of the aromatic hydrocarbon compound used, but generally has a K value of 0.1 to 0.1.
The standard value is 0.95. The K value is the Turner
Jones et al., Makromol. Chem 75 , 135-137 (1964).
The value measured according to the method described in ".", And the K value in the present invention is calculated from the following formula by measuring the X-ray diffraction of the polypropylene sheet. K = (hβ) / (hβ + hα ₁ + hα ₂ + hα ₃ ) where hβ is the diffraction intensity (height) by the β crystal (300) plane,
hα ₁ is the diffraction intensity (height) by α crystal (110) plane, hα ₂
Is the diffraction intensity (height) by the α crystal (040) plane, hα ₃ is the α crystal
Represents the diffraction intensity (height) of the (130) plane.

The polypropylene composition of the present invention is prepared by mixing the crystalline isotactic polypropylene and the aromatic hydrocarbon compound in any method. For example,
The polypropylene powder or pellets and a predetermined amount of aromatic hydrocarbon can be mixed with a tumbler, a Henschel mixer, or the like, or the above components can be kneaded with a screw extruder, a roll, or the like. In addition, the polypropylene composition of the present invention may contain other polymers, fillers, crystal nucleating agents, antioxidants, heat stabilizers, lubricants, flame retardants, antistatic agents, pigments, and other additives as required. , May be contained within a range that does not impair the effects of the present invention.

The polypropylene composition of the present invention effectively produces β-crystals during the ordinary molding process such as injection molding, compression molding, extrusion molding, etc., and improves the impact strength based on the formation of β-crystals. The effect and the effect of non-coloring can be enjoyed. Further, β crystals are generated under ordinary crystallization conditions, and from this, products such as roughened or porous sheets, films and fibers can be manufactured. The β crystal formation conditions described above are generally sufficient if the molding process conditions are maintained.

[0016]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto.

Examples 1 to 10 / Comparative Examples 1 to 4 Homoisotactic polypropylene powder PN130 manufactured by Tokuyama Soda Co., Ltd. (50% crystallinity by X-ray diffraction, ¹³
Isotactic pentad fraction 0.
Various aromatic hydrocarbons were mixed at a ratio shown in Table 1 with respect to 100 weight of 95), and melt-kneaded at 210 ° C. for 5 minutes by a Brabender blast graph. The obtained kneaded product was sandwiched between two slide glasses, melted on a hot plate set at 220 ° C., and the glass plate was pressed to obtain a sheet-shaped product. Next, it was removed from the hot plate and solidified to obtain a sheet having a thickness of about 0.5 mm. The obtained sheet was subjected to wide-angle X-ray diffraction, and the K value, which was a measure of β crystal content, was determined by the method of Turner Jones et al. The degree of coloring of the sheet was also evaluated. The results are shown in Table 1.

[0018]

[Table 1]

As shown in Table 1, the polypropylene composition of the present invention can efficiently increase the K value, that is, the amount of β crystals produced, without coloring. Since the polypropylene composition of the present invention produces a large amount of the β-crystals described above, the molded product is 1.1 to 3.
The effect of improving impact strength of 0 times can be obtained.

[0020]

The polypropylene composition of the present invention can form a large amount of β crystals under ordinary molding conditions or crystallization conditions, and has no coloring problem. Therefore, various molded articles having excellent impact strength can be produced from the polypropylene composition of the present invention by the effect based on the formation of β crystal, that is, injection molding, compression molding, extrusion molding, blow molding and the like. Further, it is possible to easily manufacture a high-value-added product such as a roughened or porous sheet, film or fiber. Further, the aromatic hydrocarbon compound as the β crystal nucleating agent of the present invention has no coloring problem and can produce various excellent molded articles.

Claims (1)

[Claims] 1. A polypropylene composition comprising 100 parts by weight of crystalline isotactic polypropylene and 0.1 to 10 parts by weight of an aromatic hydrocarbon compound having 3 or more aromatic rings in one molecule. object.