JPH09194679A - Polypropylene composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a moldable PP composition which can give moldings (e.g. rigid automotive interior parts) satisfying requirements (e.g. high rigidity, heat resistance and impact resistance) without surface defects such as flow marks. SOLUTION: A mixture comprises a polymer component being a block copolymer(BC) in which the comonomer is ethylene and a reinforcing filler being talc. BC should comprise a low-deflection-temperature type satisfying the properties: a heat distortion temperature(HDT) (ASTM D648: 0.45Mpa) of 70-107 deg.C and a Rockwell hardness (HRR) (ASTM D785) of 50-75.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a PP-based formulation containing, as a polymer component, a block copolymer in which the comonomer is ethylene and talc as a reinforcing filler. In particular, the present invention relates to a PP-based compound suitable as a molding material for automobile interior parts, which is required to have high rigidity and heat resistance as well as impact resistance. Examples of the automobile interior parts include instrument panel peripheral parts such as a lower cover / column cover for a steering wheel, a console box, a glove box, and a defroster nozzle.

[0002]

2. Description of the Related Art Recently, a block copolymer (crystallinity) in which a comonomer is ethylene is used as a molding material for automobile interior parts such as instrument panel peripheral parts.
The PP compound based on so-called impact-resistant PP is easy to reuse and leads to resource saving and environmental protection.
Moreover, it is the mainstream because it is cheap.

[0003]

However, the above block copolymer alone satisfies the high rigidity (flexural modulus: 2200 MPa or more) and heat resistance (HDT: 115 ° C. or more) required for the above-mentioned automobile interior parts. It is difficult to let For this reason, a reinforcing filler such as talc is blended to deal with it, but blending talc significantly reduces the impact resistance of the block copolymer itself, and the required impact resistance (Izod impact value: 65 J / m or more) cannot be obtained (Comparative Example 3 against Comparative Example 2).

Therefore, ethylene propylene rubber (EP
Although olefin-based elastomers such as R) are blended in the solution, addition of EPR to PP blends tends to cause surface defects such as flow marks in the molded product due to a decrease in material flow.

In view of the above, the present invention is a PP that can be molded without causing surface defects such as flow marks, while satisfying the high rigidity, heat resistance and impact resistance required for hard automobile interior parts. The purpose is to provide a system formulation.

[0006]

The PP compound of the present invention solves the above problems by the following constitution.

(1) The first invention according to claim 1 is a polypropylene (PP) compound containing a block copolymer in which the comonomer is ethylene as a polymer component, and talc as a reinforcing filler, in the block copolymer. As a heat deflection temperature (HDT) (ASTM D648: 0.45 MPa) 70 to 107 ° C. Rockwell hardness (HRR) (ASTM D785) A low deflection temperature type that satisfies the physical properties of 50 to 75 is included. .

(2) In the second invention according to claim 4, in addition to the low deflection temperature type in the first invention, heating deflection temperature (HDT) (ASTM D648: 0.45 MPa) 108 to 130 ° C. Rockwell It is characterized by including a high deflection temperature type that satisfies hardness (HRR) (ASTM D785) 76-100.

[0009]

Detailed Description of Means Hereinafter, the constitution (means) of the present invention will be described in detail.

(1) The PP-based compound of the present invention comprises a block copolymer in which the comonomer is ethylene (hereinafter sometimes abbreviated as "BC") and contains talc as a reinforcing filler. And

Here, BC containing ethylene as a comonomer
Is generally marketed as an impact resistant grade. The ethylene content of what is on the market is usually
It is in the range of 2 to 10 wt%. It is estimated that if it is less than 2 wt%, it is difficult to obtain impact resistance, and if it exceeds 10 wt%, it becomes difficult to secure the rigidity and tensile strength originally possessed by PP.

(2) The first invention is, as BC, a low heat deflection temperature (HDT) (ASTM D648: 0.45 MPa) 70 to 107 ° C. Rockwell hardness (HRR) (ASTM D785) which satisfies physical properties of 50 to 75. It is a characteristic requirement to include those of deflection temperature type.

If the HDT is less than 70 ° C., it is difficult to obtain the high rigidity and heat resistance required for automobile interior products even if talc is added,
If it exceeds 107 ° C, it becomes difficult to obtain the required impact resistance when talc is mixed.

If the HRR is too low, similarly, even if talc is blended, it is difficult to obtain the high rigidity and heat resistance required for automobile interior parts. On the other hand, if it is too high, when talc is blended, the required resistance is high. It becomes difficult to obtain impact resistance.

This low deflection temperature type BC is usually HDT: 95 to 107 ° C., HRR: 55 because of its easy availability.
The one in the range of to 70 is used.

(2) In the second invention, in addition to the low deflection temperature type in the first invention, heating deflection temperature (HDT) (ASTM D648: 0.45 MPa) 108 to 130 ° C. Rockwell hardness (HRR) The characteristic requirement is to include a high deflection temperature type that satisfies (ASTM D785) 76-100.

This high deflection temperature type BC is a general-purpose type that has been used as a base for conventional interior parts for automobiles, and the numerical ranges of the above HDT and HRR are sharply distinguished from those of the low deflection temperature type. It has no critical significance.

By blending BC with a high deflection temperature type and a low deflection temperature type, the impact resistance is slightly reduced as compared with the case of only the low deflection temperature type, but the rigidity and heat resistance are secured. Becomes easy (Example 1 and Example 2
3). At this time, as the high deflection temperature type, HDT
And HRR is as low as possible, that is, HDT: 11
When the temperature is 2 ° C. or less and the HRR is 90 or less, the impact resistance is less likely to decrease and is desirable (see Examples 2.3).

The mixing ratio (weight ratio) of the low deflection temperature type and the high deflection temperature type of the block copolymer is the former / the latter = 2/8 to 8/2, usually the former / the latter =, depending on the required characteristics. It is set to 4/6 to 6/4. If the low deflection temperature type is too small, it is difficult to obtain impact resistance, and if the high deflection temperature type is too small, it is difficult to improve rigidity and heat resistance.

This high deflection temperature type BC is normally used in the range of HDT: 105 to 120 ° C. and Rockwell hardness: 80 to 95 because of its easy availability.

(3) In order to obtain required rigidity and heat resistance, talc is blended in the low deflection temperature type BC alone or in the BCs including the high deflection temperature type BC in order to obtain required rigidity and heat resistance. The blending amount of talc is the total amount of polymer components (usually B
C total amount) 10 to 70 parts by weight per 100 parts by weight, preferably 20 from the balance of impact resistance and rigidity / heat resistance
-60 parts by weight. In addition to 100 parts by weight of the polymer component, in addition to the polypropylene BC,
This is because a blend of another olefinic crystalline polymer, high-density PE, etc. is assumed within a range that does not impair the effects of the present invention.

BC including this low deflection temperature type BC,
Even if talc is blended, not only is the impact resistance hardly lowered as in the conventional case (Comparative Example 1 and Example 2), but in the case of only the low deflection temperature type BC, on the contrary, the impact resistance is improved. (Comparative Example 1 and Example 1).

(4) The PP compound of the present invention comprises a talc, and if necessary, a stabilizer and a release agent in addition to the above low deflection temperature type BC or BC in which the high deflection temperature type BC is blended. It is prepared by mixing auxiliary materials such as a colorant and an inorganic / organic filler other than talc, mixing and kneading, and granulating (pelletizing).

The PP compound thus prepared is used as an injection or extrusion molding material for automobile interior parts.

[0025]

As described above, the PP-based composition of the present invention contains BC as a polymer component, which is ethylene as a comonomer, and PP as a reinforcing filler in a PP-based composition. Heat deflection temperature (HDT) (ASTM D648: 0.45MPa) 70-107 ℃ Rockwell hardness (HRR) (ASTM D785) Talc is blended by including a low deflection temperature type that satisfies the physical properties of 50-75. However, not only does the impact resistance not decrease, but in the case of only the low deflection temperature type BC, on the contrary, the impact resistance is improved.

Therefore, the PP-based compound of the present invention can be molded without causing surface defects such as flow marks, while satisfying the high rigidity, heat resistance and impact resistance required for hard automobile interior parts. Becomes

[0027]

[Test example]

(1) In order to support the effects of the present invention, each BC having the specifications shown in Table 1 was used, blended with the compounding recipe shown in Table 2, and pelletized, and each physical property test of the following items was conducted. went. The test specifications and test conditions are shown below.

Melt Flow Rate (MFR) ... ASTM D 1238 (A
Method): Test temperature 230 ° C Test load 21.18N Flexural rigidity… ASTM D 790 Heat deflection temperature (HDT)… ASTM D648: Test load 0.45M
Pa Izod impact ... ASTM D 256 Appearance ... Visual judgment of flow mark presence (○: None,
Χ: Yes): Molding conditions: Nissei Plastic Industry Co., Ltd. 80 ton molding machine, resin temperature; 170 ° C, 180 ° C, 210 ° C, 200 ° C (heater temperature from the hopper side) (2) The above test results are shown in Table 2. Shown in.

The comparative example 1 in which the BC has only a low deflection temperature type does not have sufficient rigidity and heat resistance, but the examples 1 and 4 in which talc is added to the comparative example 1 are of course improved in rigidity and heat resistance. In fact, it is surprising that the impact resistance is improved.

In Examples 2, 3, and 5 in which BC is a blend of a low deflection temperature type and a high deflection temperature type, talc formulation 30 is used.
It can be seen that, compared with Example 1 in which the parts are the same, the impact resistance is reduced, but the heat resistance is improved.

Further, the comparative example 2 in which the BC is only a high deflection temperature type does not have sufficient rigidity, and the comparative example 3 (conventional example) in which talc is added to improve the rigidity has a significantly high impact resistance. It was found that the resin composition containing ethylene propylene rubber had a low impact resistance and the impact resistance was improved to some extent (lower than those of the Examples), but there was a problem with the moldability (appearance) due to the presence of flow marks. .

[0032]

[Table 1]

[0033]

[Table 2]

Claims (8)

[Claims] 1. A polypropylene (PP) -based formulation comprising, as a polymer component, a block copolymer in which the comonomer is ethylene, and talc as a reinforcing filler, wherein the block copolymer comprises a heat deflection temperature (HDT) (ASTM D648). : 0.45 MPa) 70 to 107 ° C. A PP compound containing a low deflection temperature type that satisfies Rockwell hardness (HRR) (ASTM D785) 50 to 75. 2. The ethylene content of the block copolymer is 2 to 10 wt%.
The PP-based formulation described in 1. 3. The PP-based compound according to claim 1, wherein the compounding amount of the talc is 10 to 100 parts by weight based on 100 parts by weight of the total amount of the polymer components. 4. A polypropylene (PP) compound containing a crystalline block copolymer, wherein the comonomer is ethylene, as a polymer component, and talc as a reinforcing filler, wherein the block copolymer has a heat deflection temperature (HDT). (ASTM D648: 0.45MPa) 70-107 ° C Rockwell hardness (HRR) (ASTM D785) In addition to low deflection temperature type that satisfies physical properties of 50-75, heat deflection temperature (HDT) (ASTM D648: 0.45MPa) MPa) 108 to 130 ° C. A PP-based compound containing a high deflection temperature type that satisfies Rockwell hardness (HRR) (ASTM D785) 76 to 100. 5. The ethylene content of both the low deflection temperature type and the high deflection temperature type of the block copolymer is 2 to 10
PP according to claim 4, characterized in that it is wt.
System formulation. 6. The mixing ratio (weight ratio) of the low deflection temperature type and the high deflection temperature type of the block copolymer is
The latter is 2/8 to 8/2 and is characterized in that
The PP-based formulation described in 1. 7. The mixing ratio (weight ratio) of the low deflection temperature type and the high deflection temperature type of the block copolymer is
The latter = 2/8 to 8/2, wherein
The PP-based formulation described in 1. 8. The PP-based blend according to claim 4, wherein the blending amount of the talc is 10 to 70 parts by weight based on 100 parts by weight of the total amount of the polymer components.