JP2828810B2 - Polypropylene resin composition - Google Patents

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 having a good balance of physical properties such as impact resistance, rigidity and hardness, and more particularly to materials for exterior parts such as bumpers and side moldings of automobiles. The present invention relates to a polypropylene resin composition suitably used as a resin.

[0002]

2. Description of the Related Art
2. Description of the Related Art A polypropylene resin composition based on a polypropylene resin is widely used as a material for exterior parts of automobiles, for an outer plate member such as a bumper and a side molding. Then, a polypropylene resin composition has been proposed in which physical properties such as impact resistance, surface gloss, and paintability are improved by changing a rubber component and the like to be blended with a polypropylene resin as a base.

[0003] However, these polypropylene resin compositions are excellent in partial physical properties, but are comprehensive in various properties such as impact resistance and rigidity required for outer plate members of automobile bumpers, side moldings and the like. It is not well balanced and a balanced composition has not yet been developed. The development of a resin composition having an excellent balance of various physical properties is an urgent task which is most required in the automobile industry.

[0004] Specifically, resin compositions as shown in the following publications 1 to 4 have been proposed, but none of them have sufficiently satisfactory physical properties. 1. JP-A-60-152543 This is a composition obtained by adding a random copolymer of ethylene and α-olefin to polypropylene, but the impact resistance and surface gloss are improved, but the flowability and surface hardness are insufficient. There is. 2. JP-A-64-16848 This is a composition obtained by adding ethylene / α-olefin random copolymer and low molecular weight ethylene / α-olefin random copolymer to polypropylene, but the impact resistance is improved, but the heat resistance is improved. However, there is a disadvantage that the properties, fluidity and surface hardness are insufficient.

[0005] 3. JP-A-64-66263 and JP-A-1-132649
No. This is a composition obtained by adding an amorphous ethylene / propylene copolymer or a low-crystalline ethylene / propylene copolymer to a high-rigidity propylene / ethylene block copolymer. There is a drawback that heat resistance is insufficient. 4. Japanese Patent Application Laid-Open No. Hei 1-204949 A propylene / ethylene block copolymer blended with ethylene / propylene copolymer rubber, ethylene / α-olefin copolymer, and talc. Impact strength and dimensional stability are improved. However, there is a disadvantage that heat resistance and surface hardness are insufficient. The present invention has been made in view of the above circumstances, and has various physical properties such as impact resistance, rigidity, and hardness.
In particular, it is an object of the present invention to provide a polypropylene resin composition having an excellent balance between low-temperature impact resistance and hardness and fluidity.

[0006]

According to the present invention, there is provided a polypropylene resin composition comprising the following components (A), (B) and (C). (A) The content of α-olefin units other than propylene is 4 mol% or less, the mmmm fraction in pentad fraction measured by ¹³ C-NMR is 96% or more, and the intrinsic viscosity [η] is 0.7 dl / g to 1 Propylene copolymer X having an intrinsic viscosity [η] of 3.5 dl / g
The polypropylene resin composed of the above propylene copolymer Y and the total amount of the components (A) and (B) are 80 to 60.
(B) The rubber component comprising the following components (I) and (II) is 20 to 40% by weight based on the total amount of the components (A) and (B). (I) The propylene content is 35 to 60% by weight and Mooney. Ethylene propylene copolymer rubber having a viscosity ML _{1 + 4} (100 ° C.) of 10 to 80 30 to 70% by weight (II) A butene content of 12 to 25% by weight and a melt index of 0.5 to 10 g / 10 minutes Ethylene butene
(1) 70 to 30% by weight of copolymer (C) A total amount of (A) and (B) components of styrene resin is 1
3 to 15 parts by weight based on 00 parts by weight (D) 3 to 15 parts by weight based on 100 parts by weight of the total amount of the components (A) and (B)

Hereinafter, the present invention will be described in more detail.
First, each component and its characteristics will be described in detail. (A) Component In the polypropylene resin composition of the present invention, the polypropylene resin used as the (A) component is a crystalline polymer obtained by polymerizing a propylene monomer as a main component. As comonomers to be copolymerized with the propylene monomer, ethylene, butene, pentene, hexene, 3-
Methylbutene-1, 4-methylbutene-1, 2-methylpentene-1, vinylcyclohexane, 1,5-hexadiene, 1,7-octadiene, 3-methyl-1,4-
Comonomers such as hexadiene and 4-methyl-1,4-hexadiene are exemplified.

[0008] The polypropylene resin used as the component (A) comprises a propylene copolymer X having the following characteristics and a propylene copolymer X having the following characteristics. Content of α-olefin unit other than propylene is 4 m
ol% or less The propylene copolymer X has an α-olefin unit content other than propylene of 4 mol% or less, preferably 3 m
ol% or less. If the content of α-olefin units other than propylene exceeds 4 mol%, rigidity and heat resistance are insufficient. The pentad fraction (mmmm fraction) is 96% or more. The mmmm fraction in the present invention is a value obtained by performing measurement by ¹³ C-NMR. Propylene copolymer X
Is m in the pentad fraction measured by ¹³ C-NMR.
The mmm fraction is 96% or more, preferably 96.5% or more,
More preferably, it is 97% or more. If the value of the mmmm fraction is less than 96%, the hardness and heat resistance are insufficient.

The intrinsic viscosity [η] is 0.7 dl / g to 1.
5 dl / g The propylene copolymer X has an intrinsic viscosity [η] of 0.7 to 1.5 dl / g measured in decalin at 135 ° C.
When the intrinsic viscosity [η] is less than 0.7 dl / g, impact strength and heat resistance are insufficient, and when it exceeds 1.5 dl / g, moldability is reduced. More preferable intrinsic viscosity [η] of the propylene copolymer X is 0.85 to 1.4 dl / g, particularly 0.9 to 1.4 dl / g.
1.3 dl / g. Intrinsic viscosity [η] is 3.5 dl / g or more The propylene copolymer Y has an intrinsic viscosity [η] measured in decalin at 135 ° C. of 3.5 dl / g or more. If the intrinsic viscosity [η] is less than 3.5 dl / g, the impact strength decreases. The more preferable intrinsic viscosity [η] of the propylene copolymer Y is 3.7 dl / g or more, particularly 4.0 or more dl / g.
g. The content ratio (X: Y ratio) between the copolymer X and the copolymer Y in the polypropylene resin (A) is 7
0-95: 30-5, especially 75-92.5: 25-7.
A value of 5 is desirable in terms of impact strength, fluidity and balance. When only the copolymer X is used, the impact strength is insufficient.
In addition, when only the copolymer Y is used, moldability, hardness and heat resistance are insufficient.

The polypropylene resin used as the component (A) has an MI (melt index) of 10 to 70.
g / 10 min, preferably in the range of about 20 to 60 g / 10 min. If the MI is less than 10 g / 10 minutes, the moldability may be poor, and if the MI exceeds 70 g / 10 minutes, the impact resistance tends to decrease.

The amount of the polypropylene resin used as the component (A) is 80 to 60% by weight, preferably 78 to 63% by weight, more preferably 75 to 60% by weight of the total amount of the components (A) and (B). 65% by weight. If it exceeds 80% by weight, the impact strength decreases, and if it is less than 60% by weight, the moldability decreases.

(B) Component The rubber component used as the component (B) is composed of the following components (I) and (II). (I) Ethylene / propylene copolymer rubber (EPR) The propylene content in EPR is 35 to 60% by weight,
Preferably 40 to 55% by weight, more preferably 42 to 5%.
3% by weight. If the propylene content is less than 35% by weight, the impact strength decreases, and if it exceeds 60% by weight, the hardness decreases. Mooney viscosity of EPR ML _{1 + 4} (100 ℃)
Is 10 to 80, preferably 30 to 75, more preferably 35 to 70. If the Mooney viscosity is less than 10, the impact strength decreases, and if it is 80 or more, poor dispersion results.

(II) Ethylene / butene-1 copolymer (E
BM) The C ₄ (butene) content in the EBM is 12 to 25% by weight, preferably 15 to 20% by weight. If the C ₄ content is less than 12% by weight, the impact strength decreases, and if it exceeds 25% by weight, the hardness decreases. The melt index of the EBM is 0.5 to 10 g / 10 min, preferably 1 to 5 g.
/ 10 minutes. Melt index is 0.5g / 10
If it is less than 10 minutes, the fluidity is reduced, and if it exceeds 10 g / 10 minutes, the impact strength is reduced.

[0014] The compounding amount of the above (I) EPR and (II) EBM is such that EPR is 30 to 50% of the total amount of EPR and EBM.
70% by weight (EBM is 70 to 30% by weight). EP
When the proportion of R is less than 30% by weight, the impact strength becomes insufficient,
If it is 70% by weight or more, the hardness and heat resistance are insufficient.

Component (C) The styrene resin used as the component (C) may be a styrene homopolymer or a styrene copolymer obtained by copolymerizing styrene with a copolymerizable monomer. Or high impact polystyrene reinforced with a rubbery polymer.

Examples of monomers copolymerizable with styrene in the styrene copolymer include, for example, aromatic monovinyl compounds such as o-methylstyrene, m-methylstyrene, p-methylstyrene, p-chlorostyrene, acrylonitrile, Acid anhydrides of unsaturated dicarboxylic acids such as vinyl cyanide such as methacrylonitrile and maleonitrile, and maleic anhydride, itaconic anhydride and citraconic anhydride;
Maleimides such as maleimide and N-phenylmaleimide; esters of acrylic acid and methacrylic acid such as methyl methacrylate and methyl acrylate; and unsaturated carboxylic acids such as acrylic acid and methacrylic acid.
Each of these copolymerizable monomers may be used alone or in combination of two or more.

The high-impact polystyrene reinforced with a rubber-like polymer includes a rubber-like polymer such as polybutadiene rubber, polyisoprene rubber, styrene-butadiene copolymer rubber and the above-mentioned styrene homopolymer or copolymer. In the presence of the blend or the rubbery polymer,
A copolymer obtained by homopolymerizing styrene or copolymerizing styrene with the copolymerizable monomer can be used. The method for producing the styrene resin is not particularly limited, and a conventionally known method can be used.

The amount of the styrene resin used as the component (C) is 3 to 15 parts by weight, preferably 5 to 13 parts by weight, based on 100 parts by weight of the total of the components (A) and (B). . If the amount of the styrene resin is less than 3 parts by weight, the improvement of the hardness is insufficient, and if it exceeds 15 parts by weight, the impact strength is insufficient.

Component (D) Examples of the styrene elastomer used as the component (D) include at least one polymer block composed of an aromatic vinyl compound unit and at least one polymer block composed of a conjugated diene compound unit. A single polymer block is used, but the polymer block composed of the conjugated diene compound unit may be partially or entirely hydrogenated.

The monomer forming the polymer block composed of the aromatic vinyl compound unit includes, for example,
Styrene, o-methylstyrene, p-methylstyrene,
Examples thereof include alkylstyrene such as p-tert-butylstyrene, p-methoxystyrene, and vinylnaphthalene. Of these, styrene and p-methylstyrene are particularly preferable. Each of these aromatic vinyl compounds may be used alone or in combination of two or more.

On the other hand, examples of a monomer forming a polymer block composed of a conjugated diene compound unit include, for example,
Butadiene, isoprene, piperylene, methylpentadiene, phenylbutadiene, 3,4-dimethyl-1,3
-Hexadiene, 4,5-diethyl-1,3-octadiene and the like. Of these, butadiene and isoprene are particularly preferred. Each of these conjugated diene compounds may be used alone or in combination of two or more. The method for producing the styrene-based elastomer is not particularly limited, and a conventionally known method can be used. Generally, an anionic polymerization method is used.

The compounding amount of the styrene elastomer used as the component (D) is 100% in total of the components (A) and (B).
It is 3 to 10 parts by weight, preferably 5 to 8 parts by weight based on parts by weight. If the amount of the styrene-based elastomer is less than 3 parts by weight, the impact strength is reduced, and if it exceeds 10 parts by weight, the altitude is reduced.

The polypropylene resin composition of the present invention comprises:
If necessary, various additives such as a pigment, a heat stabilizer, an antioxidant, and an ultraviolet absorber can be added.

The method for producing the polypropylene resin composition of the present invention is not particularly limited. For example, the polypropylene resin composition of the present invention can be produced by kneading the above components (A), (B) and (C) by a usual mechanical kneading method. Specifically, for example, a method using a general melt kneader such as a Banbury mixer, a single screw extruder, a twin screw extruder, a multi-screw extruder, a coneder extruder and the like can be adopted. The kneading is 18
It is preferable to carry out at a temperature of about 0 to 240 ° C.

The method of forming the composition of the present invention is not particularly limited, and it does not matter whether the forming method is extrusion molding, hollow molding, injection molding, sheet molding, thermoforming, rotational molding, lamination molding, or the like. Although the effects of the present invention are exhibited in molded articles, injection molding is most suitable.

[0026]

Examples and Comparative Examples Next, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. The resin compositions of Examples 1 to 7 and Comparative Examples 1 to 7 were manufactured and subjected to physical property tests. The physical property test was performed as follows. Izod impact strength was performed in accordance with JIS-K7110 under the conditions of 23 ° C and -30 ° C. Rockwell hardness was measured in accordance with JIS-K7202. Melt index (MI) This was performed according to JIS-K7210. The heat distortion temperature was measured in accordance with JIS-K7207.

The pentad fraction of the polypropylene resin as the component (A) was measured as follows. As a pentad fraction measuring device, JNM-EX400 ( ¹³
C nuclear resonance frequency was measured under the following conditions. Measurement mode: Scalar decoupling method Pulse width: 9.0 μs (45 °) Pulse repetition time: 4 s Number of integrations: 10,000 times Solvent: Mixed solvent of 1,2,4-trichlorobenzene / deuterated benzene (90/10 volume%) Sample concentration: 200 mg / 3.0 ml Solvent Measurement temperature: 130 ° C. In this case, the pentad fraction was determined by measuring the splitting peak in the methyl group region of the ¹³ C-NMR spectrum.
The assignment of the peak in the methyl group region is described in “Macr-omolecul
es, 13 (2), 267 (1980) (A. Zambelli et al.) ".

Example 1 The following components were used as the components (A) to (D). Component (A): ethylene unit content: 2 mol%, pentad fraction: 96.5%, intrinsic viscosity [η]: 0.95 dl
/ G of a propylene copolymer of 88% by weight and an intrinsic viscosity [η] of 12% by weight of a propylene copolymer of 4 dl / g, with a MI of 40 g / 10 min. Component (B): (I) Propylene copolymer rubber (EPR)
Having a propylene content of 50% by weight and a Mooney viscosity of 70, (II) an ethylene / butene-1 copolymer (E
BM) having a butene content of 16% by weight and a melt index of 3.5 g / 10 minutes was used. Mixing ratio is E
PR was 10% by weight and EBM was 20% by weight. Component (C): High impact polystyrene (HT-51 manufactured by Idemitsu Petrochemical Co., Ltd. ) was used. Component (D): A styrene-ethylene / butylene-styrene copolymer (Clayton G1652 manufactured by Shell Chemical Co., Ltd. ) was used.

70% by weight of component (A) and component 3 of component (B)
0% by weight (EPR 10.0% by weight, EBM 20.0% by weight) and dry blending of 10 parts by weight of the component (C) and 4 parts by weight of the component (C) with respect to 100 parts by weight of the total amount. Thereafter, using a single-axis kneader, the mixture was kneaded at a temperature of 200 ° C. and a rotation speed of 80 rpm to obtain pellets. afterwards,
The obtained pellet was injection molded at a molding temperature of 220 ° C. to prepare a test piece, and a physical property test was performed. Table 1 shows the results.

Example 2 Example 1 had a butene content of 17% by weight and an MI of 1.5.
The same operation as in Example 1 was performed except that g / 10 min of EBM was used.

Example 3 The same operation as in Example 1 was carried out except that EPR having a propylene content of 50% by weight and a Mooney viscosity of 30 was used.

Example 4 In Example 1, the blending amount was 80% by weight of PP,
The same operation as in Example 1 was performed except that PR was 7.5% by weight and EBM was 12.5% by weight.

Example 5 In Example 1, the compounding amount was 20% by weight of EPR and EBM1
The same operation as in Example 1 was performed except that the amount was 0% by weight.

Example 6 The same operation as in Example 1 was carried out except that the amount of high impact polystyrene was changed to 15 parts by weight.

Example 7 In Example 1, the block PP had an intrinsic viscosity of 0.9 d.
The same operation as in Example 1 was performed except that a block PP having the same properties was used except that the propylene copolymer contained 1 / g of the propylene copolymer and the propylene copolymer having an intrinsic viscosity of 5 dl / g.

Comparative Example 1 In Example 1, the amount of EPR was 3 without using EBM.
The same operation as in Example 1 was performed except that the amount was 0% by weight.

Comparative Example 2 In Example 1, the amount of EBM was 3 without using EPR.
The same operation as in Example 1 was performed except that the amount was 0% by weight.

Comparative Example 3 The same operation as in Comparative Example 1 was performed, except that EPR having a propylene content of 25% by weight and a Mooney viscosity of 30 was used.

Comparative Example 4 In Example 1, the blending amount was 50% by weight of block PP,
The same operation as in Example 1 was performed except that PR was 25% by weight and EBM was 25% by weight.

Comparative Example 5 In Example 1, the limiting viscosity was 0.95 as the block PP.
dl / g propylene copolymer and intrinsic viscosity 2 dl / g
The same operation as in Example 1 was performed except that a block PP having the same characteristics as above was used except that the propylene copolymer was used.

Comparative Example 6 The same operation as in Example 1 was performed, except that the blending amount of the high impact polystyrene was changed to 20 parts by weight.

Comparative Example 7 The same operation as in Example 1 was performed, except that high impact polystyrene and a styrene-ethylene / butylene-styrene copolymer were not used.

[0043]

[Table 1]

[0044]

As described above, the polypropylene resin composition of the present invention is excellent in the balance of various physical properties such as impact strength, rigidity and hardness. Therefore, the propylene resin composition of the present invention can be used for automobile exterior parts. And the polypropylene resin composition of the present invention can be effectively used as a material for an outer plate member such as an automobile bumper or side molding.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 53:02) (C08L 23/14 23:16 23:08 51:04 53:02) (72) Inventor Takashi Sumitomo Chiba 1-1, Anemaki Kaigan, Ichihara-shi Idemitsu Oil Oil Chemical Co., Ltd. (72) Inventor Toshitaka Kanai 1-1-1, Anesaki Kaigan, Ichihara-shi, Chiba Prefecture Idemitsu Oil Chemical Co., Ltd. 1 Toyota Town, Toyota Motor Corporation (72) Inventor Takao Nomura 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Takezumi Nishio 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Vehicle (56) References JP-A-2-279750 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08L 23/00-23/36 C08L 25/00-25 / 18 C08L 51/04 C08L 53/02

Claims (1)

(57) [Claims] 1. A polypropylene resin composition comprising the following components (A), (B), (C) and (D). (A) The following properties, and the content of α-olefin units other than propylene is 4 m
ol% or less in pentad fraction measured by ¹³ C-NMR.
A propylene copolymer X having an mm fraction of 96% or more and an intrinsic viscosity [η] of 0.7 dl / g to 1.5 dl / g, and a propylene having an intrinsic viscosity [η] of 3.5 dl / g or more as described below. 80 to 60% by weight of the total amount of the components (A) and (B) of the polypropylene resin composed of the copolymer Y (B) The rubber components composed of the following components (I) and (II) are represented by (A), ( 20 to 40% by weight of the total amount of component B) (I) Ethylene / propylene copolymer rubber 30 to 70 having a propylene content of 35 to 60% by weight and a Mooney viscosity ML _{1 + 4} (100 ° C.) of 10 to 80 (II) ethylene butene having a butene content of 12 to 25% by weight and a melt index of 0.5 to 10 g / 10 min.
(1) 70 to 30% by weight of copolymer (C) A total amount of (A) and (B) components of styrene resin is 1
3 to 15 parts by weight based on 00 parts by weight (D) 3 to 15 parts by weight based on 100 parts by weight of the total amount of the components (A) and (B)