JPH07316356A - Flexible polypropylene-based resin composition - Google Patents

Abstract

PURPOSE:To obtain a polypropylene-based resin composition excellent in flexibility, transparency, impact resistance, resistance to whitening, weathering resistance cold resistance, moldability, scratch resistance, mechanical properties, etc. CONSTITUTION:This resin composition comprises (A) 70-5wt.% of a crystalline polypropylene-based resin and (B) 30-95wt.% of an ethylene/styrene/>=5C alpha-olefin copolymer elastomer with the styrene content and alpha-olefin content at 0.01-30mol% and >=30mol%, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene resin composition, and more specifically to a polypropylene resin composition excellent in flexibility, transparency, impact resistance, whitening resistance, cold resistance, mechanical properties and the like. It is about.

[0002]

2. Description of the Related Art In order to improve the flexibility and impact resistance of polypropylene, a polypropylene resin composition blended with an ethylene / propylene elastomer has been conventionally known. However, when these elastomers are blended with polypropylene, the obtained resin composition is inferior in transparency and whitens when an impact is applied,
It was insufficient in terms of impact resistance, flexibility, transparency and whitening resistance.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has flexibility, transparency, impact resistance, whitening resistance, weather resistance, cold resistance, moldability, It is an object of the present invention to provide a polypropylene resin composition having excellent scratch resistance, mechanical properties, etc., particularly a polypropylene resin composition having excellent flexibility, transparency, whitening resistance, and cold resistance, and having well-balanced physical properties.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, completed the present invention. That is, in the present invention, the crystalline polypropylene resin (A): 70 to 5% by weight, ethylene / styrene /
α-olefin copolymer elastomer (B): 30 to 9
5% by weight, and the ethylene / styrene / α-olefin copolymer elastomer has a styrene content of 0.01 mo.
1% or more and 30 mol% or less, the α-olefin has 5 or more carbon atoms, and the α-olefin content is 30 mol% or more, which is a polypropylene resin composition.

The details will be described below.

As the crystalline polypropylene resin used in the present invention, those generally used can be used. For example, polypropylene, ethylene content 20-70
Wt% propylene / ethylene block copolymer, ethylene content 0.5-12 wt% propylene / ethylene random copolymer, ethylene content 0.5-12 wt%, α-olefin content 0.5- 20% by weight of a propylene / ethylene / α-olefin terpolymer and the like can be mentioned.

Ethylene / styrene / α-olefin copolymer Eras 5 tomer (B) used in the present invention
The α-olefin used in the above has a carbon number of 5 or more, for example, 1-pentene, 1-hexene, 4-methyl-
1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-
Tridecene, 1-tetradecene, 1-pentadecene, 1
-Hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicodecene and the like,
These 1 type (s) or 2 or more types are used. Above all,
From the viewpoint of easy availability, 1-hexene, 4-methyl-1-pentene, 1-octene and the like are preferable.

It is essential that the ethylene / styrene / α-olefin copolymer elastomer (B) used in the present invention has an α-olefin content of 30 mol% or more. α-olefin content is 30 mol%
When it is less than 1, the compatibility with the crystalline polypropylene resin (A) used together with the ethylene / styrene / α-olefin copolymer elastomer (B) becomes poor, and the balance is obtained in the effect of improving flexibility, transparency and impact resistance. It becomes difficult to obtain a high polypropylene resin composition. The styrene content is 0.01 mol% or more and 30 mol%
It must be within the following range. When the styrene content is less than 0.01 mol%, the composition of the present invention has a problem in molding appearance and stickiness and is inferior in mechanical properties. Further, a copolymer elastomer having a styrene content of more than 30 mol% is not preferable because it is disadvantageous in terms of synthesis and is inferior in transparency, cold resistance and impact resistance improving effect.

Further, the molecular weight of the ethylene / styrene / α-olefin copolymer elastomer (B) used in the present invention is not particularly limited, but the number average measured by gel permeation chromatography (GPC). The molecular weight is 5000 in terms of polyethylene
It is preferably ˜1,000,000, and more preferably 10,000 to 600,000. If the number average molecular weight is less than 5,000, the effect of modifying the properties of the composition of the present invention is small and the problem of surface stickiness may occur. On the other hand, if the number average molecular weight exceeds 1,000,000, the flowability of the resulting composition is increased. There is a possibility that the moldability will be reduced and the molding process will become difficult.

The method for producing the above-mentioned ethylene / styrene / α-olefin copolymer elastomer is not particularly limited, and it can be produced using various catalysts such as titanium catalyst, vanadium catalyst or metallocene catalyst. . Above all, it is preferable to use a metallocene catalyst having excellent copolymerizability for production. This makes it possible to obtain a copolymer having a high yield and a narrow composition distribution.

The composition of the present invention comprises a crystalline polypropylene resin (A) and an ethylene / styrene / α-olefin copolymer elastomer (B) with a compounding ratio of 7
It is 0 to 5% by weight / 30 to 95% by weight, and can be arbitrarily changed according to the intended use and required physical properties. However, if the blending amount of the crystalline polypropylene resin (A) exceeds 70% by weight, the flexibility of the composition becomes poor,
On the other hand, if it is less than 5% by weight, the strength is remarkably lowered, which is not preferable.

The resin composition of the present invention can be obtained by blending the crystalline polypropylene resin (A) and the elastomer (B) by a commonly used method, including a kneader, roll, Banbury mixer, extruder and the like. Is preferably used for the melt blending.

The above-mentioned crystalline polypropylene resin (A)
The ethylene / styrene / α-olefin copolymer elastomer (B) composition has excellent compatibility. The compatibility index includes, for example, mechanical relaxation represented by dynamic viscoelasticity measurement, further dielectric relaxation, magnetic relaxation, and the like. It is also possible to measure using. When the compatibility is evaluated from the temperature dispersion in the tensile mode of dynamic viscoelasticity, the loss tangent (tan δ) based on the glass transition temperature in the polymer blend having poor compatibility shows a maximum according to each glass transition temperature, Usually, it does not become a single peak but exhibits two or more peaks. Further, accordingly, the maximum value of the peak also becomes a relatively small value, which is a value smaller than 0.2.

On the other hand, the resin composition of the present invention has a maximum value of tan δ at a temperature lower than the temperature showing the maximum value of tan δ caused by the glass transition temperature of the polypropylene resin used in the above-mentioned dynamic viscoelasticity measurement. Is present, the peak is a single peak, and the size of the peak is 0.2 or more, and the compatibility is extremely excellent. Since the maximum value of tan δ exists on the low temperature side, the cold resistance is superior to that of the polypropylene resin alone.

The resin composition of the present invention is highly flexible and has a tensile storage modulus (E ') at 23 ° C. of not more than 5 × 10 ⁹ dyn / cm ^{2 in} the above-mentioned dynamic viscoelasticity measurement. . For example, even if tan δ shows a single peak,
If E ′ at 23 ° C. exceeds 5 × 10 ⁹ dyn / cm ² , the softening effect becomes poor. In addition, E '
Was applied at a frequency of 10 Hz, and measurement was performed in a linear region where stress and strain were proportional.

The composition of the present invention is excellent in transparency and whitening resistance. That is, the composition of the present invention has a tensile elongation of 300
% Or less, whitening does not occur visually, and the haze value at a thickness of 1 mm is 40% or less.

As described above, the composition of the present invention has a higher impact resistance than the conventional polypropylene resin composition using the ethylene / propylene copolymer elastomer.
The composition has excellent transparency, flexibility and whitening resistance, and has a good balance of physical properties.

In the composition of the present invention, if necessary, calcium carbonate, mica, talc, silica, barium sulfate, calcium sulfate, kaolin, clay, pyroferrite, bentonite, serisanite, zeolite, nepheline sinite, attapulgite. , Wollastonite, ferrite, calcium silicate, magnesium carbonate, dolomite, antimony trioxide, zinc oxide, titanium oxide, magnesium oxide, iron oxide, molybdenum disulfide,
Inorganic fillers and organic materials such as graphite, gypsum, glass beads, glass powder, glass balloons, quartz, quartz glass, etc.
Inorganic pigments can also be added. Further, a release agent, a slip agent, a lubricant, a heat resistance stabilizer, a weather resistance stabilizer, a foaming agent, a rust preventive agent, an ion trap agent, a flame retardant, a flame retardant auxiliary agent, etc. may be added as necessary. Further, it is possible to blend the composition of the present invention with other resins. In this case, the third
It is also possible to use a compatibilizing agent of the present resin composition and another resin together as a component.

As described above, the polypropylene resin composition obtained by the above-mentioned method is blended with a reinforcing filler, an inorganic filler and the like, and various molded articles are obtained by injection molding, extrusion molding, inflation molding and calender molding. It can be formed into a film, a sheet, a tube or the like.

[0020]

EXAMPLES The present invention will be described below with reference to examples, but these are illustrative and not restrictive. Various measurements in the examples were carried out by the following methods.

(Measurement of styrene and hexene-1 content of ethylene / styrene / hexene-1 copolymer elastomer) Using o-dichlorobenzene as a solvent, 100 MHz,
¹³ C-NMR spectrum (manufactured by JEOL Ltd. JNM
GX400) was calculated.

(Measurement of Molecular Weight and Molecular Weight Distribution) o-
It was determined in terms of polyethylene using gel permeation chromatography (150C type GPC manufactured by Millipore Corporation) at 140 ° C. using dichlorobenzene.

(Haze) A pressed test piece having a thickness of 1 mm was used for measurement according to JIS K7105.

(Measurement of Dynamic Viscoelasticity) A viscoelasticity measuring analyzer RSA which is a measuring device based on the non-resonance type forced vibration method.
Using II (Rheometrics Far East Co., Ltd.), the temperature dependence of dynamic viscoelasticity was measured at a measurement frequency of 10 Hz, a measurement mode: tension, and a temperature rising rate: 5 ° C./min.
The applied strain was in the linear region of 0.1% or less.
In this measurement, loss tangent (tan δ) and storage elastic modulus (E ′) were measured.

(Tensile test) Using a press test piece having a thickness of 1 mm, a No. 2 type test piece at a speed of 50 mm / min according to JISK
7113.

(Self-adhesion test) Two pressed test pieces having a thickness of 1 mm were superposed, and a load of 30 g / cm ² was applied at 23 ° C.
After a lapse of a week, it was evaluated whether or not it would wear itself.

Reference Example 1 Synthesis of ethylene / styrene / hexene-1 copolymer elastomer To a 2 l autoclave, 250 ml of toluene, 50 ml of styrene and 300 ml of hexene-1 were added, and ethylene was fed so that the ethylene pressure was 16 kg / cm ^2. Introduced. Next, 10 ml of toluene and 5 mmol of methylaluminoxane were added to another reaction vessel and synthesized by a known method (dimethyl (t-butylamide) (tetramethyl-η).
5 μmol of 5-cyclopentadienyl) silane) dichloride titanium was added, and the mixed solution was stirred for 20 minutes and then introduced into an autoclave to start polymerization. This polymerization was carried out at 90 ° C. for 30 minutes while keeping the ethylene pressure at 16 kg / cm ² .

After the completion of the polymerization, the polymer was washed with a large amount of ethanol and dried under reduced pressure at 60 ° C. for 12 hours. As a result, the styrene content was 2 mol% and the hexene-1 content was 3
30 g of a 4 mol% ethylene / styrene / hexene-1 copolymer elastomer was obtained. The number average molecular weight of this elastomer was 54000 and Mw / Mn = 2.0.

Example 1 Propylene / ethylene random copolymer (ethylene content: 3.6%, MFR: 10 g / 10 minutes (230 ° C.,
2.16 kgf)) 25 g and 2 parts of the ethylene / styrene / hexene-1 copolymer elastomer obtained in Reference Example 1
5 g, a hindered phenolic stabilizer (Irganox 1010 (manufactured by Ciba Geigy)) as a heat stabilizer,
Phosphorus-based stabilizers (Irgafos 168 (manufactured by Ciba Geigy)) and 2000 ppm each of calcium stearate as a lubricant were melt-blended at 60 rpm for 5 minutes at 200 ° C. using a Labo Plastomill (internal volume 100 cc). Then, the obtained composition was press-molded. 0.5mm thick and 5m wide from this sample
A strip-shaped test piece with m and a length of 25 mm was cut out and used as a test piece for measuring dynamic viscoelasticity, and evaluated. The results are shown in Table 1. It can be seen that this composition is excellent in compatibility, and is excellent in flexibility, whitening resistance and transparency imparting effect.

Comparative Example 1 Instead of the ethylene / styrene / hexene-1 copolymer elastomer used in Example 1, the hexene-1 content was 27.
A composition was obtained and evaluated in the same manner as in Example 1 except that an ethylene / styrene / hexene-1 copolymer elastomer having a mol% and a styrene content of 2 mol% was used. The results are shown in Table 1.

Comparative Example 2 Instead of the ethylene / styrene / hexene-1 copolymer elastomer used in Example 1, an ethylene / hexene-1 copolymer elastomer (hexene-1 content 34 m) was used.
The composition was obtained and evaluated in the same manner as in Example 1 except that the composition was used. The results are shown in Table 1. Although this ethylene / hexene-1 copolymer elastomer had excellent compatibility with polypropylene resin and was excellent in flexibility, transparency and whitening resistance, it self-adhered.

[0032]

[Table 1]

[0033]

As described above, the resin composition of the present invention is a polypropylene resin composition which is excellent in flexibility, transparency, impact resistance, whitening resistance, cold resistance, mechanical properties, etc. and has a good balance of physical properties. Is.

Claims (4)

[Claims] 1. A crystalline polypropylene resin (A): 70
Up to 5% by weight, ethylene / styrene / α-olefin copolymer elastomer (B): 30 to 95% by weight,
The styrene content of the ethylene / styrene / α-olefin copolymer elastomer is 0.01 mol% or more and 30 mol.
%, The α-olefin has 5 or more carbon atoms, and the α-olefin content is 30 mol% or more. 2. The loss tangent (tan δ) based on the glass transition temperature obtained from the temperature dependence of dynamic viscoelasticity appears as a single peak on the lower temperature side than the crystalline polypropylene resin alone, and the peak size is 0. .2 or more, and
Storage elastic modulus (E ′) at 23 ° C. is 5 × 10 ⁹ dyn
/ Cm < ² > or less, The polypropylene resin composition of Claim 1 characterized by the above-mentioned. 3. The polypropylene-based resin composition according to claim 1, which is not whitened by a tensile elongation of 300% or less. 4. The polypropylene resin composition according to claim 1, wherein the haze value at a thickness of 1 mm is 40% or less.