JPH0563503B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to an impact-resistant polypropylene composition, and more specifically, a mixture of isotactic polypropylene and ethylene-α-olefin rubber is grafted with an α,β-unsaturated carboxylic acid or a derivative thereof. The present invention relates to a polypropylene composition having extremely excellent impact resistance and comprising an organic compound having two or more hydroxyl groups in one molecule. Prior Art Isotactic polypropylene is inexpensive and has excellent mechanical properties, transparency, heat resistance, surface gloss, chemical resistance, acid resistance, and alkali resistance.
In addition, it is easy to mold using various molding methods such as injection molding, blow molding, and various types of film molding, so it is used in large quantities for a very wide range of applications. It has the disadvantage of being small. As a method of improving the impact resistance of such isotactic polypropylene, polypropylene is injected with ethylene/propylene rubber (EPR) or EPR.
A method of mixing polyethylene (PE) and polyethylene (PE) is generally well known. Methods for mixing EPR and PE with polypropylene include a method in which a two-stage or three-stage reactor is used in a polymerization system, and a method in which mechanical post-blending is performed using a kneader or the like. The thus obtained polypropylene and EPR, or polypropylene and EPR and PE
A mixture (or block copolymer) with
It is known as HIPP, but compared to isotactic homopolypropylene, impact resistance is improved by 2 to 4 times. However, the absolute value of impact resistance is at most 5 to 9 in terms of Izotsu impact strength.
Kg·cm/cm ² , which is still insufficient for applications that require extremely high impact resistance, such as automobile bumpers, motorcycle fenders, and helmets. OBJECTS OF THE INVENTION It is therefore an object of the present invention to provide polypropylene compositions that are more impact resistant than those currently known as high impact polypropylenes (HIPP). Structure of the invention According to the invention, (i) isotactic polypropylene; (ii) an α-olefin content of 25 to 60% by weight;
(i):(ii) with ethylene-α-olefin rubber consisting of an ethylene-α-olefin random copolymer of
=90:10~70:30 (weight ratio) mixture α, β-
Ethylene glycol, propylene glycol, polyethylene glycol, _CH2 (OH) _-CH2 - _CH2CH (OH) for 100 parts by weight of the grafted product (A) grafted with unsaturated carboxylic acid or its derivative.
_CH2 − _CH2 −OH, A compound having two or more hydroxyl groups in one molecule selected from a compound in which -OH groups are bonded to low molecular weight polyethylene with a molecular weight of about 500 to 2000, ethylne-vinyl acetate/vinyl alcohol copolymer, and polyvinyl alcohol (B) High impact polypropylene compositions are provided comprising from 1 to 35 parts by weight. Detailed Description of the Structure and Effects of the Invention According to the present invention, as described above, a grafted product obtained by grafting α,β-unsaturated carboxylic acid, etc. onto a mixture of isotactic polypropylene and ethylene-α-olefin rubber is used. By blending with an organic compound having two or more hydroxyl groups in one molecule, a polypropylene composition has extremely high impact resistance with an Izot impact strength of 30 to 70 kg cm/ ^cm2 , as explained below. It can be suitably used in applications that require extremely high impact resistance, such as automobile bumpers, motorcycle fenders, and helmets. The isotactic polypropylene used in the present invention includes propylene homopolymers and copolymers of propylene and a small amount of α-olefin. Polymerization is carried out by slurry polymerization using a low-volatility poor solvent or propylene monomer that does not dissolve in the solvent, or by gas phase polymerization without using a solvent. The above-mentioned copolymer of propylene and α-olefin is preferably a random copolymer having an α-olefin content of 5% by weight or less. α- of random copolymer
If the olefin content exceeds 5% by weight, the rigidity decreases, which is not preferable. α-olefin content used in the present invention 25
The α-olefin in the ~60% by weight ethylene-α-olefin random copolymer rubber is, for example, propylene, butene-1, hexene-1, etc., and if necessary, hexadiene, ethylidene norbornene, etc. can be used as a third component. Add the diene of
Using a Ziegler-based catalyst or Vanazine-based catalyst,
Polymerization is carried out by a solution method, slurry method, or gas phase method. According to the present invention, (i) isotactic polypropylene and (ii) ethylene-α-olefin copolymer rubber are in a weight ratio of (i):(ii)=90:10 to 70:30. mixed to become Such mixing may include, for example, polymerizing isotactic polypropylene;
This is then supplemented with α such as ethylene or butene-1.
- This may be done by charging olefins and copolymerizing them to mix (or block) them in a polymerization reactor, or by polymerizing each separately and using a general extruder or kneader. It may also depend on the method of mixing. If the mixing ratio of the ethylene-α-olefin copolymer rubber is less than the above-mentioned ratio, the impact resistance will be insufficient, whereas if it is larger than the above ratio, the impact resistance will be good but the rigidity will decrease, which is not preferable. According to the invention, the above mixture is prepared by combining α,β-unsaturated carboxylic acids or derivatives thereof (e.g. acrylic acid,
Grafting is carried out with meccrylic acid, fumaric acid, itaconic acid, hymic acid, maleic acid, or anhydride thereof, with maleic anhydride being preferred. Isotactic polypropylene and ethylene-α-
The amount of α,β-unsaturated carboxylic acid etc. grafted to the mixture with the olefin copolymer rubber is 0.1 to 5% by weight, preferably 0.2 to 1% by weight based on the weight of the grafted product.
Weight%. If the grafting amount of α,β-unsaturated carboxylic acid, etc. is less than 0.1% by weight, the desired effect of improving impact resistance will not be observed.On the other hand, if it exceeds 5% by weight, there is no particular problem, but the impact resistance This is not preferred because no further improvement effect is observed and it is not economical. The method for grafting α,β-unsaturated carboxylic acid, etc. to the above mixture is carried out, for example, as follows. Examples of radical generators used for graft modification include dicumyl peroxide, benzoyl peroxide, di-t-butyl peroxide, and 2,5-
Dimethyl-2,5-di(t-butylperoxy)
Organic peroxides such as hexane, lauroyl peroxide, and t-butyl peroxybenzoate are preferably used, and two or more thereof may be used in combination. Examples of the graft modification method include adding a graft monomer and a radical generator to a polyolefin suspended or dissolved in an appropriate solvent and stirring the mixture under heating; There are methods of melt-kneading using a Banbury mixer, a kneader, etc., but the latter method is generally simpler. Note that the amounts of the radical generator and graft monomer used for radical modification are not particularly limited, but 0.001 to 0.5 parts by weight of the radical generator, α, β-
0.1 to 10 parts by weight of unsaturated carboxylic acid or derivative thereof. According to the present invention, the above-mentioned grafted product is mixed with an organic compound having two or more hydroxyl groups in one molecule. Such organic compounds include, for example, the general formula HO-R-OH (R is a saturated or unsaturated aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, a saturated or unsaturated aliphatic group, or It refers to an aromatic hydrocarbon group containing an alicyclic hydrocarbon group, and one in which the hydrocarbon group is substituted with a functional group such as amine, carboxyl, ester, thiol, or alcohol, or a halogen atom such as chlorine, fluorine, or bromine. )R
If has the structure as above, HO-R-
The OH compound may be a low molecular compound, a high molecular compound, or a modified polymer. The mixture of the grafted product and the organic compound having two or more hydroxyl groups in one molecule can be carried out by any general mixing method, for example, using a Banbury mixer, a kneader or an extruder. The two may be mixed under conditions in which both are molten, or both may be dissolved and mixed in a solvent such as toluene or xylene, but the former is generally preferred. The organic compound is blended in an amount of 1 to 35 parts by weight, preferably 5 to 15 parts by weight, per 100 parts by weight of the grafted material. If the amount of the organic compound is less than 1 part by weight, the effect of improving impact resistance will not be sufficient, and if it exceeds 35 parts by weight, the rigidity, strength, fluidity, etc. of the polypropylene will be significantly changed, which is not preferable. The mechanism by which the impact resistance of the polypropylene composition according to the present invention is significantly improved is not clear, but in conventional high impact polypropylene (HIPP), the rubber component (EPR) with impact absorption effect is continuous with polypropylene. Whereas it was simply dispersed in the phase,
In the polypropylene composition according to the present invention, α,β-unsaturated carboxylic acid etc. bonded to polypropylene dispersion and ethylene-α-olefin copolymer rubber molecules and an organic compound having two or more hydroxyl groups in one molecule. The hydroxyl group of the compound reacts to create an ester bond, and the polypropylene molecule and ethylene-α-
It is thought that this is because the olefin copolymer rubber molecules bond with each other, increasing the affinity and bonding force at the interface between the continuous phase and the dispersed phase (ester bonds are actually confirmed in the infrared absorption spectrum). Examples Examples of the present invention will be described below, but it goes without saying that the scope of the present invention is not limited to these examples. In addition, in the example, "%" and "part"
Unless otherwise specified, "% by weight"
and "parts by weight". The physical properties were measured using the following method. MFI: Measured at 230℃ according to JIS-K6758. Shore D: ASTM-D-2240 Izot impact strength: 25℃ according to JIS-K6758
Measured in (Kg・cm/cm ² ). Tensile strength: Measurement example according to JIS-K6758 1 MFI consisting of 80% isotactic polypropylene and 20% ethylene-propylene random copolymer rubber with a propylene content of 35% (measured at 230°C according to JIS-K6758) 6.0 (g) /10 minutes) peroxide (dicumyl peroxide).
0.1PHR) and 0.5PHR of maleic anhydride.
In the extruder, 0.35% maleic anhydride was grafted. This grafted product was used as component A, and on the other hand, ethylene with a vinyl acetate content of 33% and an MI (measured at 190°C according to JIS-K6730) of 92.5 (g/10 min)
An ethylene/vinyl acetate/vinyl alcohol copolymer obtained by hydrolyzing a vinyl acetate copolymer with a saponification rate of 93% was used as the B component, and 97 parts of the A component and 3 parts of the B component were mixed using Laboplastomill. using temperature
Blend for 5 minutes at 200°C. The physical properties of the grafted product (blank) before blending and the polypropylene composition after blending (Example 1) were measured, and the obtained results are shown in Table 1. As is clear from the results in Table 1, the Izot impact strength of the blank was 65 Kg·cm/cm ² , whereas the Izot impact strength of the obtained polypropylene composition of Example 1 was 35.6 Kg·cm/cm ² A significant improvement in impact resistance was observed. Examples 2 to 6 The maleic anhydride grafted product obtained in Example 1 was used as the A component, and the various ethylene/vinyl acetate/vinyl alcohol copolymers shown in Table 1 were used as the B component to convert the A and B components. A polypropylene composition was obtained by blending in the same manner as in Example 1 in the proportions shown in Table 1. The physical properties of the resulting composition were measured in the same manner as in Example 1, and the results are shown in Table 1.

[Table] Example 7 MFI consisting of 82% isotactic polypropylene and 18% ethylene-propylene random copolymer rubber with a propylene content of 48% (measured at 230°C)
10.0 (g/10 min) of polypropylene mixture and dicumyl peroxide (Diecap).
Mixing reaction in a kneader using 0.2PHR and 2PHR of MAH, maleic anhydride (MAH) 1.0%
was grafted. Using this grafted product as the A component, and using the ethylene/vinyl acetate/vinyl alcohol copolymer used in Example 1 as the B component, 97 parts of the A component and 3 parts of the B component were heated using a Laboplastomill. Blend for 5 minutes at 200°C. The physical properties of the grafted product (blank) before blending and the polypropylene composition after blending (Example 7) were measured in the same manner as in Example 1, and the obtained results are shown in Table 2. As is clear from the results in Table 2, the Izot impact strength of the blank was 5.2, whereas the Izot impact strength of the obtained polypropylene composition of Example 7 was 40, indicating a significant improvement in hardness. . Examples 8 to 11 Using the same component B as in Example 7, changing the MFI, rubber compounding amount, and bonding amount of maleic anhydride of the polypropylene mixture of component A as shown in Table 2,
Alternatively, a polypropylene composition was obtained by changing the blend ratio of component A and component B. The physical properties of the resulting composition were measured in the same manner as in Example 1, and the results are shown in Table 2.

[Table] Examples 12 and 13 MFI6.2 (230°C, g/
10 minutes) was grafted in the same manner as in Example 1 to obtain a grafted product with a maleic anhydride bond content of 0.53%. Using this grafted product as component A, the polyethylene glycol shown in Table 3 was added to component B.
It was used as a component and blended as in Example 1. The physical properties of the obtained polypropylene composition were measured in the same manner as in Example 1, and the results are shown in Table 3.

[Table] Recall*3

Claims (1)

[Claims] 1 (i) isotactic polypropylene; (ii)
Ethylene-α with α-olefin content of 25-60% by weight
- Ethylene-α-olefin rubber consisting of an olefin random copolymer (i):(ii)=90:10-70:
Graft compound in which α,β-unsaturated carboxylic acid or its derivative is grafted to a mixture of 30 (weight ratio)
(A) For 100 parts by weight, ethylene glycol, propylene glycol, polyethylene glycol,
CH ₂ (OH)−CH ₂ −CH ₂ CH(OH)CH ₂ −CH ₂ −
Oh, Compounds with two or more hydroxyl groups in one molecule selected from compounds in which -OH groups are bonded to low molecular weight polyethylene with a molecular weight of about 500 to 2000, ethylene-vinyl acetate/vinyl alcohol copolymers, and polyvinyl alcohol (B) An impact-resistant polypropylene composition comprising 1 to 35 parts by weight.