JPH064737B2 - Modified propylene polymer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a modified propylene polymer composition which is preferably used as an extrusion, injection or hollow molding material in the fields of automobiles and home appliances.

[Conventional technology]

A propylene-ethylene copolymer commercially available as a so-called propylene block copolymer is prized in various industrial fields as a resin having excellent impact resistance and rigidity.
However, it is inferior in whitening resistance, and when stress is applied, the stressed parts are liable to be whitened and the appearance of the molded product is likely to be impaired, which is a problem especially when applied to products that emphasize appearance, such as automobile parts and home appliances. It was.

Conventionally, as a method for improving such a problem, a method of blending polyethylene with a propylene copolymer (Japanese Patent Laid-Open No. 55-5).
No. 8245 and Japanese Patent Application Laid-Open No. 57-137341) have been proposed, but the improvement of impact bleaching resistance was insufficient and uniform blending was difficult. A method for producing a propylene block copolymer by a two-step polymerization method (Japanese Patent Laid-Open No. 56-55416) has also been proposed, but a method having a satisfactory balance of impact resistance, rigidity and whitening resistance is obtained. Has not been done.

On the other hand, there is known a method of performing heat treatment for modification in order to improve the fluidity of a propylene copolymer (Japanese Patent Laid-Open No. 58-76444), but the drawback is that the fluidity and mechanical properties are poorly balanced. was there.

[Problems to be solved by the invention]

The present invention is intended to provide a modified propylene polymer composition which has solved the conventional problems and is excellent in whitening resistance, impact resistance, rigidity and fluidity.

[Means for solving problems]

That is, the modified propylene polymer composition of the present invention comprises (A) the following two components polymerized using a stereoregular catalyst: (a) a propylene-ethylene copolymer 70-having an ethylene content of 2% by weight or less; A propylene polymer consisting of 95% by weight and (b) 30 to 5% by weight of a propylene-ethylene copolymer having an ethylene content of 10 to 50% by weight is heat treated in the presence of an organic peroxide to give a decomposition degree of 1.2.
To 80 parts by weight of the polymer, and (B) 0.02 to 2.0 parts by weight of an ester of an aliphatic saturated monovalent carboxylic acid having 12 to 22 carbon atoms and a polyhydric alcohol. .

The propylene polymer polymerized using the stereoregular catalyst (A) used in the present invention is produced by a multistage polymerization method, for example, a two-stage polymerization method.

The stereoregular catalyst used for the polymerization is a catalyst generally used for stereoregular polymerization reactions of ethylene, propylene and the like, and is usually a catalyst composed of a transition metal halogen compound component and an organoaluminum compound component. Here, as the transition metal halogen compound, a halide of titanium is preferable, and titanium trichloride is particularly preferable. As titanium trichloride, titanium tetrachloride reduced by various methods is activated by further ball milling and / or solvent washing (for example, washing with an inert solvent and / or an inert solvent containing a polar compound). Titanium trichloride or titanium trichloride eutectic (eg TiCl
₃ + 1 / 3AlCl ₃ ) further co-milled with amine, ether, ester, sulfur, halogen derivative, organic or inorganic nitrogen compound or phosphorus compound; from titanium trichloride liquefied in the presence of ether compound Examples thereof include those obtained by precipitation; those obtained by the method described in JP-B-53-3356. It is also possible to use a titanium halide supported on a magnesium compound.

Other components of the organoaluminum compound include those represented by the following formula: AlR _n X _3-n (wherein R represents an alkyl group, an alkoxy group or an aryl group having 1 to 10 carbon atoms, and X represents a halogen atom). , N represents a value of 0 <n ≦ 3.) Is preferable. Specifically, for example,
Triethyl aluminum, triisobutyl aluminum, tri-n-propyl aluminum, diethyl aluminum monochloride, diethyl aluminum monobromide, diethyl aluminum monoiodide, diethyl aluminum monoethoxide, diisobutyl aluminum monoisobutoxide, diethyl aluminum monohydride, diisobutyl Aluminum monohydride, ethylaluminum sesquichloride, ethylaluminum dichloride and the like can be mentioned, and one or more of these can be used.

In these catalyst components, usually, 1 mol of the organoaluminum compound is used per 1 mol of the transition metal halogen compound.
The mixture is used in a molar ratio. Further, various electron donating compounds can be used as the third component to improve the catalytic performance.

Such a stereoregular catalyst is used at each stage of the polymerization reaction in the amount and the combination of each component that are usually used.

As the polymerization method, a known method can be applied,
For example, slurry polymerization, solution polymerization, gas phase polymerization, liquid phase polymerization using a propylene or ethylene monomer as a medium can be mentioned.

In the case of production by the two-stage polymerization method, in the first stage, the propylene-ethylene copolymer having an ethylene content of 2% by weight or less in the polymer is controlled so as to form 70 to 95% by weight of the whole polymer. , (A) component. Preferably 74-9
Control so as to produce 3% by weight. The use of a copolymer having an ethylene content of more than 2% by weight in the first stage is not suitable because the rigidity of the resulting composition is significantly reduced.

In the second stage, ethylene is further polymerized with the polymer obtained in the first stage polymerization reaction so that the ethylene content is from 10 to 10.
The propylene-ethylene copolymer, which is 50% by weight, is controlled so as to form 5 to 30% by weight, preferably 7 to 26% by weight, based on the total polymer, and the component (b) is used.

A copolymer having an ethylene content of less than 10% by weight (b)
When it is used as a component, the impact resistance of the resulting composition is lowered, and when it is more than 50% by weight, the effect of improving the whitening resistance of the composition is insufficient.

When the amount of the produced propylene-ethylene copolymer of the component (b) is less than 5% by weight of the total polymer, the impact resistance of the composition is lowered, and when it is more than 30% by weight, the composition of It reduces the rigidity.

The melt index of the obtained propylene polymer was 0.1.
-50 g / 10 min, preferably 0.5-35 g / 10 min.

The propylene polymer obtained by this two-stage polymerization method preferably has a triad fraction: [R] / f _EEE of 2 or more measured by ₁₃ C-NMR from the viewpoint of its structural characteristics. This is because a polymer having an [R] / f _EEE of 2 or more can further improve the whitening resistance of a composition produced using the polymer.

Here, [R] means the sum of chains in which propylene and ethylene are bonded in the polymer (f _PPE + f _PEP + f _EEP +
f _EPE and E are ethylene and P is propylene), and f _EEE is a chain in which three ethylenes are bonded.
Further, regarding the attribution of peaks at the time of measuring the triad fraction, Macromolecules, Vol. 11, p. 33, 1
Judgment is made based on the method described in 1978 (Macromolecules, Vol 11, P33, 1978).

The polymer (A) of the present invention is obtained by subjecting the above-mentioned propylene polymer to heat treatment in the presence of an organic peroxide to modify it,
It is adjusted to a range of 1.2 to 80, preferably 1.5 to 50. As the organic peroxide that can be used here,
Ketone peroxides such as methyl ethyl ketone peroxide and methyl isobutyl ketone peroxide; n-
Peroxyketals such as butyl-4,4-bis (t-butylperoxy) valerate; hydroperoxides such as cumene hydroperoxide and diisopropylbenzene hydroperoxide; 1,3-bis (t-butylperoxyisopropyl) Dialkyl peroxides such as benzene and dicumyl peroxide; Diacyl peroxides such as benzoyl peroxide and decanoyl peroxide; Percarbonates such as bis- (4-t-butylcyclohexyl) peroxydicarbonate; t-butylperoxy Examples thereof include peroxyesters such as acetate and t-butylperoxylaurate, which have a 10-hour half-life temperature of 100 ° C. or higher and 1
The minute half-life temperature is preferably equal to or higher than the melting point of the propylene polymer. Such substances include cumene hydroperoxide, diisopropylbenzene hydroperoxide, 1,3-bis (t-butylperoxyisopropyl) benzene, dicumyl peroxide and the like.

Further, the heat treatment of the propylene polymer is usually performed at a melting temperature of the polymer or higher and lower than the decomposition temperature, by adding an appropriate amount of the above-mentioned organic peroxide to the polymer, and then adding a single-screw extruder, a twin-screw kneader, a kneader, a Banbury. It is performed by melt-kneading with a mixer, a roll or the like. The heat treatment conditions at this time are the decomposition degree (that is, the melt index (MI
The ratio ( ₀ ) to the melt index (MI ₁ ) of the resin after modification) may be selected in the range of 1.2 to 80, preferably 1.5 to 50. If the degree of decomposition is less than 1.2, the degree of modification is small and the resulting modified propylene polymer composition does not have sufficient fluidity, resulting in poor processability. On the other hand, when it exceeds 80, the decomposition proceeds too much and the impact resistance is lowered.

The component (B) which is another component of the composition of the present invention is an ester of an aliphatic saturated monovalent carboxylic acid having 12 to 22 carbon atoms and a polyhydric alcohol.

The carboxylic acid may be any aliphatic saturated monovalent carboxylic acid having 12 to 22 carbon atoms, and specifically, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenin. An acid etc. can be mentioned.

Examples of polyhydric alcohols are dihydric alcohols such as ethylene glycol, propylene glycol, ethylethylene glycol, trimethylene glycol and tetramethylene glycol; trihydric alcohols such as propanetriol, methylpropanetriol, butanetriol, pentanetriol and hexanetriol; Eritrit,
Examples thereof include tetrahydric alcohols such as pentaerythritol, diglycerin, and sorbitan; pentahydric alcohols such as adnit and arabite; and hexahydric alcohols such as alit, talit, sorbit, and mannite. Particularly, trihydric alcohol is preferable.

Among the esters synthesized from these aliphatic saturated monovalent carboxylic acids and polyhydric alcohols, those suitable for use in the present invention are aliphatic saturated monovalent carboxylic acids having 13 to 20 carbon atoms and polyhydric alcohols. Is a monoester of. Specifically, stearic acid monoglyceride, palmitic acid monoglyceride, myristic acid monoglyceride and the like can be mentioned.

These may be used alone or in an appropriate mixture of two or more kinds.
If it is 0% by weight or less, unsaturated ester, other carboxylic acid, alcohol and the like may be contained.

In addition, the composition of the present invention, in addition to the usual antioxidants, antistatic agents, anti-UV agents, neutralizing agents, pigments and the like in predetermined amounts,
If necessary, they can be added and compounded.

When producing the composition comprising (A) and (B) in the present invention, 0.02 to 2.0 parts by weight of the ester (B) is blended with 100 parts by weight of the above-mentioned polymer (A). When the amount of the ester compounded is less than 0.02 parts by weight, the effect of improving the whitening property of the composition is poor, and when it exceeds 2.0 parts by weight, the bleeding phenomenon frequently occurs and the surface properties are deteriorated. There is no choice but to be restricted in use. The amount is preferably 0.1 to 1.5 parts by weight, more preferably 0.1 to 1.0 part by weight.

In the case of carrying out the present invention, a method of heat-treating a propylene polymer in the presence of an organic peroxide and then blending the ester (B), a method of blending the propylene polymer and the ester (B), and then an organic peroxide Method of adding and heat treating,
It is possible to employ a method in which the propylene polymer, the ester (B) and the organic peroxide are blended and then heat treated. The method is preferable from the viewpoint of operational convenience, but similar effects can be obtained by other methods.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited thereto.

Examples 1 to 3 and Comparative Examples 1 and 2 Propylene polymers shown in Table 1 were produced by a conventional two-step polymerization. As a fatty acid ester, a: stearic acid monoglyceride (manufactured by Riken Vitamin Co., Ltd., trade name Riquemar S-10) is used with respect to 100 parts by weight of this propylene polymer.
0) or b: a predetermined amount of palmitic acid monoglyceride (trade name NAA-160 manufactured by NOF CORPORATION) and 0.01
~ 0.06 parts by weight of 1,3-bis (t-butylperoxyisopropyl) benzene are added and mixed homogeneously, 220
The pellets of the modified propylene polymer composition were produced by melt-kneading with an extruder at ℃.

The pellet was injection-molded to prepare a test piece. The test results are shown in Table 1.

Example 4 Propylene polymer 1 produced in the same manner as in Examples 1 to 3.
1,3-bis (t-butylperoxyisopropyl) benzene was added to 00 parts by weight, and melt-kneaded with an extruder at 220 ° C. to obtain a polymer. To 100 parts by weight of this polymer, 0.5 parts by weight of stearic acid monoglyceride (Riken Vitamin Co., Ltd., trade name Rikemar S-100) was added and pelletized.

The pellet was injection-molded to prepare a test piece. The test results are shown in Table 1.

Ethylene content: According to infrared spectrum.

MI: In accordance with JIS K-7210 Drop weight impact strength: In accordance with DuPont method (impulse tip bending rate: 0.25 inch, anvil inner diameter: 2 inches) Bending elastic modulus: In accordance with JIS K-7203 Impact whitening area: After injection molding Place a square plate (65 mm x 65 mm x 3.2 mm) on the pedestal of a DuPont falling weight impact tester, with the center of the square plate in contact with the tip of a 1/2 inch hammer rod, A weight of 1 kg was dropped from the height of 50 cm (temperature: 23 ° C.) to the hammer core to whiten the central part of the square plate, and the whitened area (cm ³ ) was measured after standing for 1 day. The smaller this value is, the more excellent the whitening property is.

[Effects of the Invention] The modified propylene polymer composition of the present invention is excellent in all of whitening resistance, impact resistance and rigidity, and at the same time, has a good balance of three characteristics. Further, it is also excellent in fluidity and moldability, and is useful as an extrusion, injection, and hollow molding material in the fields of automobiles and home electric appliances where appearance is important, and its industrial value is extremely large.

Claims (1)

[Claims] 1. The following two components polymerized using (A) a stereoregular catalyst: (a) 70 to 95% by weight of a propylene-ethylene copolymer having an ethylene content of 2% by weight or less and (b) an ethylene content. A propylene polymer consisting of 30 to 5% by weight of a propylene-ethylene copolymer in an amount of 10 to 50% by weight is heat treated in the presence of an organic peroxide to give a decomposition degree of 1.2.
100 parts by weight of a polymer adjusted to 80 to 80 parts by weight and (B) 0.02 to 2.0 parts by weight of an ester of a fatty acid saturated monohydric carboxylic acid having 12 to 22 carbon atoms and a polyhydric alcohol. Propylene polymer composition.