JPH0549708B2 - - 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. Highly impact resistant compound containing a compound having two or more residues of a metal salt of carboxylic acid or sulfonic acid (i.e., a group in which H of a carboxyl group or a sulfonic group is replaced with a metal atom) in one molecule. Concerning superior polypropylene compositions. 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 by 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 low performance. 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/ ^cm2 , 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 The impact resistant polypropylene composition according to the invention comprises (i) isotactic polypropylene; (ii)
Ethylene-α with α-olefin content of 25-60% by weight
-(i):(ii)=90:10-70 with ethylene-α-olefin rubber consisting of olefin random copolymer:
A grafted product in which α, β-unsaturated carboxylic acid or a derivative thereof (hereinafter referred to as α, β-unsaturated carboxylic acid, etc.) is grafted onto a mixture of 30 (weight ratio)
1 to 35 parts by weight of a compound (B) having two or more residues of a metal salt of carboxylic acid or sulfonic acid in one molecule is blended with 100 parts by weight of (A)). 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 a compound having two or more residues of a metal salt of carboxylic acid or sulfonic acid in one molecule, the Izot impact strength can be increased from 15 to 70 kg/cm, as explained below.
A polypropylene composition having an extremely high impact resistance of cm ² is obtained, and can be suitably used in applications requiring extremely high impact resistance, such as automobile bumpers, motorcycle fenders, and helmets. The isotactic polypropylene used in the present invention includes a propylene homopolymer and a copolymer 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 25 used in the present invention
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. It is mixed so that it becomes. Such mixing can be carried out, for example, by polymerizing isotactic polypropylene, then charging it with an α-olefin such as ethylene or butene-1, and copolymerizing it, thereby mixing (or blocking) it in a polymerization reactor. Alternatively, the polymers may be polymerized separately and mixed using a general extruder or kneader. If the mixing ratio of the ethylene-α-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 methacrylic acid, fumaric acid, itaconic acid, hemicic 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 amount of grafted α,β-unsaturated carboxylic acid, etc. is less than 0.1% by weight, the desired effect of improving impact resistance will not be observed, and even if it exceeds 5% by weight,
Although there is no particular problem, it is not preferable because no further effect of improving impact resistance is observed and it is not economical. The method of 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 a compound having two or more residues of a metal salt of a carboxylic acid or a sulfonic acid in one molecule. Examples of compounds having two or more residues of metal salts of carboxylic acid or sulfonic acid in one molecule include, for example, the general formula R
(SO ₃ M) _o , R(COOM) _o or (SO ₃ M) _n −R−
(COOM) is expressed as l (where n≧2, m+
l ≧ 2 (m, l = 0, 1, 2, 3...), M is an alkali metal such as Na, K, Li, or an alkaline earth metal such as Zn, Mg, Ca, R is a saturated or unsaturated aliphatic or alicyclic hydrocarbons, aromatic hydrocarbons)
This compound may be a low molecular weight compound or a high molecular weight polymer having a molecular weight of 10×10 ⁴ or more. Furthermore, even if it is a low-molecular compound in which a carboxyl group, an ester group, a functional group such as an amine, an alcohol, or a halogen atom is bonded to the hydrocarbon compound represented by the above general formula,
It may also be a copolymer. Typical examples of such compounds include ethylene and metal acrylic acid salts and metal anhydride metal salts.
Examples include ternary or quaternary copolymers containing acrylic acid or acrylic esters in addition to acrylic acid metal salts, which are known as ionomers. Other examples include styrenic iso-omers containing metal acrylic acid salts, metal salts of maleic anhydride, and metal salts of sulfonate, and rubber iso-omers of ethylene and α-olefin containing metal salts of sulfonate. According to the present invention, the compound (B) having two or more residues of a metal salt of a carboxylic acid or sulfonic acid in one molecule is added to 100 parts by weight of the grafted product (A).
By adding ~35 parts by weight, preferably 5 to 15 parts by weight, the Izot impact strength can be increased from 15 to 70 kg.
A polypropylene composition with a very high impact resistance of cm/cm ² is obtained. If the blending amount of the above compound (B) is less than 1 part by weight, the effect of improving impact resistance will not be sufficient;
On the other hand, if it exceeds 35 parts by weight, the properties of polypropylene, such as processability, rigidity, and moldability, will be lost, which is not preferable. The mixture of the grafted product and a compound having two or more carboxylic acid or sulfonic acid metal salt residues in one molecule can be carried out by any general mixing method, such as a Banbury mixer, They can be mixed in a molten state using a kneader, extruder, CIM or FCM single-screw or twin-screw kneader. 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,
The polypropylene composition according to the present invention contains α,β-unsaturated carboxylic acids, etc. bonded to the polypropylene dispersion and ethylene-α-olefin copolymer rubber molecules, and two or more carboxylic acids or sulfones in one molecule. A compound having a residue of a metal salt of an acid reacts with a polypropylene molecule and ethylene-α-
This is thought to be because the olefin copolymer rubber molecules bond with each other through ionic bonds, increasing the affinity (bonding force) at the interface between the polypropylene continuous phase and the dispersed phase. 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 (JIS-K6758
6.0 (g/10 min) of the mixture (measured at 230°C according to
0.5% maleic anhydride was grafted using 0.2 PHR of dicumyl peroxide and 1.0 PHR of maleic anhydride in a kneader at 220°C. This grafted product was used as component A, while Himilan
1605 (ethylene/acrylic acid/sodium acrylic acid salt copolymer manufactured by Mitsui Polychemical Co., Ltd.) was used as the B component, and 97 parts of the A component and 3 parts of the B component were mixed at a temperature of 210°C using a Brabender plastograph. Blend for 10 minutes. 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 6.5 Kg·cm/cm ² , whereas the Izod impact strength of the obtained polypropylene composition of Example 1 was 55.0 Kg·cm/cm ² , a significant improvement in impact resistance was observed. Examples 2 to 8 Using the maleic anhydride grafted product obtained in Example 1 as component A, an ethylene-acrylic acid copolymer (the bond amount of acrylic acid
25% by weight, flow index 500g/10min or more),
CH ₃ COONa, (CH ₃ COO) ₂ Zn, CH ₃ COOLi,
NaOH, ( _CH3COO ) _2Mg or ( _CH3COO ) _2Zn
Using an ethylene/acrylic acid/acrylic acid metal salt copolymer obtained by mixing and reacting at 160°C for 15 minutes or more using a 20 to 40% aqueous solution as the B component, the A component and the B component are A polypropylene composition was obtained by blending in the same manner as in Example 1 in the proportions shown in the table. 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] *3: Methyl methacrylate *4: Methacrylic acid *5: BA (butyl acrylate)
Examples 9 to 11 The grafted product of isotactic polypropylene and ethylene-propylene random copolymer rubber used in Example 1 was used as the A component, and the following compound was used as the B component, and the A and B components were combined into a second
A polypropylene composition was obtained in the same manner as in Example 1 by blending in the proportions shown in the table. Example No. B Component 9 Styrene (92 mol%)/Acrylic acid (8 mol%) 10 Styrene (95 mol%)/Acrylic acid (5 mol%) 11 Styrene (83 mol%)/Methacrylic acid (17
(mol%) 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. In addition, the said B component was manufactured as follows. It was obtained by dissolving styrene and acrylic acid (or methacrylic acid) in toluene and reacting them in an autoclave equipped with a stirrer using benzoyl peroxide as a polymerization initiator. next,
This styrene/acrylic acid (or methacrylic acid)
The copolymer was dissolved in benzene, a methanol solution of the metal acetate shown in Table 2 was added thereto, and the mixture was reacted at 50° C. for several hours to obtain an ionized product of the copolymer.

[Table]
9 〃 〃 〃 Mg ⁺⁺ 75
150 97〓3 5.0 61 35
221 259 570
10 〃 〃 〃 Na ⁺ 100
27 95〓5 4.3 62 50
235 290 600
11 〃 〃 〃 Ca ⁺⁺ 34
35 95〓5 3.9 61 46
210 285 650

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:
Grafted product (A) in which α, β-unsaturated carboxylic acid or its derivative is grafted to a mixture of 30 (weight ratio)
Compounds containing two or more carboxylic acid or sulfonic acid metal salt residues in one molecule per 100 parts by weight
(B) An impact-resistant polypropylene composition comprising 1 to 35 parts by weight.