JPH0819295B2 - Crystalline polypropylene composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a polypropylene composition having excellent crystallinity.

<Prior Art> Polypropylene is an excellent synthetic resin having high rigidity and high mechanical strength, but is a polymer having a relatively slow crystallization rate. Therefore, depending on the field of use, there is a problem in that the crystallinity after molding is low and the rigidity is reduced, and because relatively large spherulites are formed, the transparency is poor and the commercial value is impaired.

Therefore, some attempts have been proposed to improve the crystallinity and rigidity of polypropylene. For example, aluminum salt or sodium salt of aromatic carboxylic acid
58-80329), aromatic carboxylic acids, aromatic phosphoric acid metal salts, sorbitol derivatives (Japanese Patent Publication No. 55-12460 and Japanese Patent Publication No. 58-129036), and these generate nuclei of crystal nuclei. It is known that the above problems can be alleviated by using an agent (hereinafter referred to as "nucleating agent").

<Problems to be Solved by the Invention> Among these nucleating agents, the sorbitol derivative exhibits an excellent nucleating effect, but the sorbitol derivative bleeds from the resin and causes roll fouling during film formation or during processing. It has a strong odor and its use is limited. In addition, aluminum salts of aromatic carboxylic acids that are commonly used have some drawbacks in that polypropylene is partially colored when used in combination with a weathering agent, and a large number of voids are formed when formed into a film.

<Means for Solving Problems> The present inventors have conducted extensive studies in view of such drawbacks, and as a result, hydrogenated an aromatic nucleus of a radical polymer or anion polymer of styrene or a styrene derivative represented by the following formula. The added polymer (A) (hereinafter referred to as the polymer (A)) was added to 0.
The present invention was found to be able to improve the crystallinity and rigidity of crystalline polypropylene by blending from 05 to 10,000 wtppm, and completed the present invention. Here, the radical polymer refers to a polymer using a radical polymerization catalyst, and the anionic polymer refers to a polymer using an anion polymerization catalyst (excluding a coordinated anion polymerization catalyst) (hereinafter the same). (In the formula, R ₁ represents a hydrogen atom or an alkyl group, and R ₂ represents a hydrogen atom, an alkyl group or a halogen atom.) The crystalline polypropylene referred to here is a propylene homopolymer, propylene and a carbon number of 2 to 18 It means a random or block copolymer with other α-olefins. The styrene derivative polymer used in the present invention is a homopolymer of the styrene derivative or a copolymer of the styrene derivative and a small amount of the styrene derivative.

Specific examples of styrene or a styrene derivative used in the present invention include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o, p-dimethylstyrene, o-ethylstyrene, m-ethylstyrene, o- Examples thereof include ethylstyrene, o-chlorostyrene, p-chlorostyrene, α-methylstyrene and the like.

As a radical polymerization catalyst used for the polymerization of styrene derivatives, an azo compound or a compound such as a peroxide that easily generates a radical by thermal decomposition is used.Azo compounds include azoisobutyronitrile and peroxide. Is hydrogen peroxide,
Examples include persulfates, hydroperoxides, dialkyl peroxides, diacyl peroxides, and peroxide esters. As the anionic polymerization catalyst, an alkyl or alkoxy compound such as Sr, Ca, K, Na, Li and Mg is used.

The polymerization method of the styrene derivative is not particularly limited, such as emulsion, suspension and bulk polymerization.

The polymer (A) is a radical polymer or anion polymer of the above-mentioned styrene derivative using a catalyst such as Raney nickel, palladium, ruthenium or platinum at a temperature of 50 to 300.
It can be obtained by hydrogenation under the conditions of ℃ and hydrogen pressure of normal pressure to 200 kg / cm ² · G. A method in which the hydrogenation rate is as high as possible is preferable. In order to prevent bleeding from the crystalline polypropylene composition, the polymer (A) preferably has a large molecular weight, and the number average molecular weight is preferably 3,000 or more, more preferably 10,000 or more.

The content of the polymer (A) in the crystalline polypropylene composition of the present invention is 0.05 wtpp so that the improving effect is exhibited without changing the physical properties of the crystalline polypropylene.
m ~ 10000wtppm is required, preferably 0.5wtppm ~ 500
It is 0 wtppm.

The crystalline polypropylene used in the present invention is produced by using a coordination anion polymerization catalyst, and is suitably produced by a catalyst system composed of, for example, a titanium compound and an organoaluminum compound. Examples of the titanium compound include titanium trichloride catalysts commercially available from Toyo Storfer, Toho Titanium, Marubeni and Solvay and the like. In addition, JP-A-57-599
Catalysts in which a titanium compound is supported on a magnesium compound, such as those described in JP-A No. 16 and JP-A-55-133408, are also preferably used. As an organoaluminum compound, AlX _a
R _3-a (X: halogen atom, alkoxy group, or hydrogen atom,
R: an alkyl group having 1 to 18 carbon atoms, and an alkylaluminum compound represented by a: 0 ≦ a <3) is preferable, and specific examples of the compound include Al (CH ₃ ) ₃ , Al (C ₂ H ₅ ) ₃ , Al (C ₂ H ₅ ) ₂ Cl, AL
_{(C 2 H 5) 2 Br} , Al (C 2 H 5) 2 (OC 2 H 5), Al (C 2 H 5) 2 (OC 4 H 9), Al
(C ₂ H ₅ ) (OC ₄ H ₉ ) ₂ , Al (C ₂ H ₅ ) Cl ₂ , Al (C ₄ H ₉ ) ₃ , Al (C ₂ H ₉ ) ₂ C
1, Al (C ₅ H ₁₃ ) ₃ , Al (C ₅ H ₁₃ ) ₂ Cl and the like, and mixtures thereof. Further, in order to improve the stereoregularity of the polymer during the polymerization, it is also possible to add an electron donor such as carboxylic acid ester, phosphoric acid ester or silicic acid ester and polymerize propylene.

The blending of the crystalline polypropylene and the polymer (A) is carried out by a blending method which is applied to the blending of a usual α-olefin polymer. For example, both polymer powders, granulation pellets, polymer powders and The granule pellets are mixed with a Henschel mixer or the like, and melt kneading is performed with a Brabender, roll, Banbury mixer, granulator, or the like, and further, mixing with the polymer solution is also performed. In the crystalline polypropylene composition of the present invention, all kinds of additives such as heat and light stabilizers, antistatic agents, antioxidants, carbon black, pigments, flame retardants and the like, which are usually blended with polypropylene, are added if necessary. Compounded, low density polyethylene, high density polyethylene, polybutene,
Other polymers such as EP rubber and fillers such as mica and talc can be mixed and used.

The crystalline propylene composition of the present invention can be made into various kinds of products such as sheets, films, containers and fibers by well-known techniques such as injection molding, pressure molding, vacuum molding, extrusion molding, blow molding and stretching.

Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.

The melt index (hereinafter referred to as MI), crystallization temperature, and flexural modulus shown in the examples are measured according to the following methods.

(1) MI Measured according to JIS K 6758.

(2) Crystallization temperature Using a differential scanning calorimeter (DSC), measurement was performed at a cooling rate of 4 ° C / min.

(3) Flexural modulus Measured according to JIS K 6758.

<Example> Example 1 (1) Hydrogenation Commercially available styrene homopolymer (manufactured by Nippon Polystyrene Co., Ltd.)
In a cyclohexane solvent at 150 ° C., the concentration of the polymer is 5 wt%, the hydrogen partial pressure is 30 kg / cm ² · G, the alumina-supported ruthenium catalyst (Ru
Hydrogenation was carried out under the conditions of a content of 3% by weight and a reaction time of 8 hours. The polymer (A) thus obtained was isolated from the reaction solution and subjected to GPC measurement using a carbon tetrachloride solvent. As a result, the polystyrene reduced number average molecular weight was 97,000. No absorption based on the benzene ring was observed in the UV spectrum of this polymer (A).

(2) Crystalline polypropylene composition 0.1 g of the above polymer (A) is dissolved in 20 ml of carbon tetrachloride,
This solution was homogenized in 20 g of MI 2 propylene homopolymer powder.
Was impregnated in. Then carbon tetrachloride was removed by vacuum drying
Later, as a stabilizer to 100 parts by weight of propylene homopolymer
In contrast, 0.05 parts by weight of calcium stearate, BHT (2,6-
0.2 parts by weight of di-t-butylhydroxytoluene, Irgan
ox 1010 (Ciba Geigy Antioxidant, Tetrakis
[Methylene-3 (3 ', 5'-di-t-butyl-4-hydroxy
Cyphenyl) propionate] Add 0.05 parts by weight of methane
Then, roll kneading was performed. Flexural modulus of this composition
And crystallization temperature are measured, and the above polymer (A) is blended
Measured value of propylene homopolymer with no MI 2 (comparative example
It is shown in Table 1 together with 1).

Examples 2 and 3 The amount of the polymer (A) in Example 1 was 0.
02g In Example 3, the physical properties of the blended product of polypropylene and polymer (A) were measured in the same manner as in Example 1 except that the amount was changed to 0.002g.

<Effect of the Invention> As shown in Table 1, the crystalline polypropylene composition according to the present invention has a high crystallization temperature and a high flexural modulus. It is a polypropylene with excellent crystallinity.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C08L 25:02) (56) References JP 62-1739 (JP, A) JP 62 -1738 (JP, A) JP-A-57-190033 (JP, A)

Claims (1)

[Claims] 1. A polymer (A) obtained by hydrogenating an aromatic nucleus of a polymer of styrene or a styrene derivative represented by the following formula by a radical polymerization catalyst or a polymer of an anionic polymerization catalyst (excluding a coordinated anionic polymerization catalyst). 0.05 ~ 10000w
A crystalline polypropylene composition containing tppm. (In the formula, R ₁ represents a hydrogen atom or an alkyl group, and R ₂ represents a hydrogen atom, an alkyl group or a halogen atom.)