JP3304719B2 - Polyolefin elastomer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a polyolefin elastomer composition (hereinafter abbreviated as "TPO composition").
About. Particularly, the present invention is suitable for a long injection molded product which is used in an atmosphere having a large temperature difference, such as a side molding, is required to have dimensional stability, and is also required to have moldability and coatability. Here, a side mall will be described as an example, but the invention is not limited to this.

[0002]

[Explanation of terms] Main terms (abbreviations) used in this specification
Will be described as follows.

[0003] TPO composition: a polyolefin-based elastomer composition.

[0004] Q value (M _w / M _n) ... Gerupa Mie Sho <br/> emissions chromatography weight average molecular weight measured by gel permeation chromatography (GPC) (M _w) and the ratio of the number average molecular weight (M _n).

MFR: 230 for the crystalline PP
° C, in the case of the EOR, the amount of g extruded in 10 minutes from an orifice having a diameter of 2.1 mm and a length of 8 mm when subjected to a force of 2.16 kgf at 190 ° C.

PE: polyethylene.

PP: polypropylene.

[0008]

2. Description of the Related Art As a material for the side molding as described above, a TPO composition (polyolefin-based thermoplastic resin) which does not require a vulcanizing step, is easy to reuse, and has excellent weather resistance. Elastomer material) has been widely used. And, since the side moldings made of these TPO compositions are inferior in abrasion resistance, they are generally treated by applying a coating treatment.

In general, a side molding (injection molded article) is made of a TPO composition having a hard phase component such as crystalline PP as large as about 70% by weight in order to ensure releasability and appearance of the molded article. (Japanese Unexamined Patent Application Publication No. 5-98097 / 98098)
・ See 98099). Therefore, it generally has high rigidity (flexural modulus: 1200 MPa or more, flexural strength: 20M).
Pa or more), which is causing a problem that it cannot cope with a curved body of a streamlined automobile, which has become popular in recent years. That is, the followability to the curved surface of the side molding is poor, or the adhesive area of the double-sided tape needs to be large.

For this reason, it is conceivable to use a TPO composition having a relatively low rigidity in which the ratio of a soft phase component such as ethylene propylene rubber is increased.
If the pressure is reduced to 00 MPa or less, problems are likely to occur in the releasability, the appearance of the molded product, and the like. That is, it has been difficult to form a long injection molded product in which the properties of the flexural modulus and the releasability, the appearance of the molded product, and the adhesion of the coating film are well balanced.

In view of the above, the present invention provides a TPO composition that can be molded into a long injection molded article having a good balance of flexural modulus, releasability, molded article appearance, and coating film adhesion. The purpose is to:

[0012] Another object of the present invention is to provide, in addition to the above objects,
Furthermore, while improving the releasability and appearance of the molded product,
It is an object of the present invention to provide a TPO composition capable of reducing the coefficient of linear expansion.

Still another object of the present invention is to provide a long injection molded product in which the properties of the flexural modulus and the releasability, the appearance of the molded product, and the adhesion of the coating film are well balanced.

[0014]

[Means for Solving the Problems]

(1) The TPO composition of the present invention according to claims 1 and 2 basically achieves the first object by the following constitution.

A polyolefin-based elastomer composition used for molding a coated long injection molded article having a flexural modulus of 1000 MPa or less, wherein a substantial base polymer comprises crystalline PP as a hard phase component, EOR
Is a soft phase component, and the blend ratio of the hard phase component and the soft phase component is the former / the latter (weight ratio) = 48/52 to 67/33, and the EPR and EOR The blend ratio is the former / the latter (weight ratio) = 1/9 to 9/1, and the properties of the crystalline PP are as follows: Q value (M _w / M _n ) ≧ 10, MFR: 50 to 120
And the Mooney viscosity (ML _{1 + 4} 100
C) is 3 to 35, and the specific gravity of the EOR is 0.892 or less.

(2) The TPO composition of the present invention according to claims 3 and 4 achieves the second object basically by the following constitution.

The talc according to claim 1 or 2,
It is characterized by being blended in 20 phr.

(3) The long injection molded article of the present invention solves the above-mentioned problems by the following constitution.

A molded article obtained by injection molding from the TPO composition of the above (1) or (2), wherein the design surface of the molded article is a painted surface.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments. The blending units are weight units unless otherwise specified. In addition, Comparative Examples and Examples in parentheses are in Test Examples described later.

(1) The composition of the present invention has a flexural modulus of 100
It is assumed that it is used for molding a coated long injection molded product of 0 MPa or less.

When the flexural modulus exceeds 1000 MPa, it is difficult to cope with a curved body of a streamlined automobile. That is, the followability to the curved surface of the side molding is poor, or the adhesive area of the double-sided tape needs to be large, which is not desirable.

(2) In the olefin elastomer composition, first, a substantial base polymer is made of crystalline PP
(Crystalline polypropylene) as a hard phase component and EPR
(Amorphous ethylene propylene copolymer) and EOR
(Amorphous ethylene-α-olefin (C4-C12) -based copolymer) is assumed to be a polymer alloy containing a soft phase component.

The composition of each component is determined by the blend ratio of the hard phase component and the soft phase component, the former / the latter (weight ratio) =
48/52 to 67/33 (preferably 53/47 to 6
2/38) and the blend ratio of EPR and EOR is the former / the latter (weight ratio) = 1/9 to 9/1 (desirably 3/7 to 7/3).

If the amount of the hard phase component is too small, that is, if the amount of the soft phase component is too large, a problem tends to occur in the releasability (see Comparative Example 7), and the amount of the hard phase component is too large, that is, the soft phase component is too small. In this case, it is difficult to obtain a material having a flexural modulus of 1000 MPa or less, and the linear expansion coefficient is undesirably increased (see Comparative Example 8).

Further, unless blended EPR, i.e. EOR alone, coating adhesion is hardly obtained (see Comparative Example 2), unless blended E O R, i.e. alone EPR, releasability outs in ensuring (See Comparative Example 1).

(3) The characteristic of the crystalline PP is the Q value (M _w
/ M _n ) ≧ 10 (preferably 12), MFR: 50 to 1
20 (preferably 55 to 100).

If the Q value is too small, that is, if the molecular weight distribution is too narrow and the MFR is too small, flow marks are more likely to occur, that is, a problem tends to occur in the appearance of the molded product ( See Comparative Example 6).

The crystalline PP may be a propylene homopolymer, but a small amount (usually 2 to 12%, desirably
Copolymers with ethylene (3 to 8%) are preferred because of increased compatibility with EPR.

(4) The EPR is Mooney viscosity (ML)
_{(1 + 4} 100 ° C) 3 to 35 (preferably 5 to 30) is used. If the Mooney viscosity is too high, the fluidity will be adversely affected, and flow marks will be more likely to occur, that is, problems will occur in the appearance of molded articles (see Comparative Example 3).

Further, those having a Mooney viscosity of 3 or less have poor releasability from a mold and lower adhesion of a coating film.

Here, as the EPR, an ethylene propylene binary copolymer (EPM) is usually used.
When a partially or fully crosslinked type is used, an ethylene propylene nonconjugated diene terpolymer (EPDM) obtained by copolymerizing a trace amount of a nonconjugated diene (ethylidene norbornene, dicyclopentadiene, etc.) as a third component is used. use.

The propylene content of the EPR is not particularly limited, but is usually 18 to 45% (preferably 20 to 45%).
30%).

(5) The EOR used has a specific gravity of 0.892 or less (preferably 0.870 to 0.890, more preferably 0.880 to 0.890). If the specific gravity is too high, it is difficult to obtain coating film adhesion. Although the reason cannot be determined, it is estimated that the crystallinity becomes too high and adversely affects the coating film adhesion.

As the α-olefin, C4 to C12
Butene-1, pentene-1, hexene-1, heptene-1, octene-1, nonene-1, decene-1, 4-
Methylpentene-1 and the like can be used. When a partially or fully crosslinked type is used as the EOR, a small amount of a non-conjugated diene (such as ethylidene norbornene or dicyclopentadiene) may be copolymerized as the third component, as in the case of the EPR.

The α-olefin content in the EOR is not particularly limited, but is 10 to 22% (preferably 12 to 20%).
%). If the α-olefin content is too low, the amorphousness of the EOR tends to be low (the crystallinity is high) and the linear expansion coefficient tends to be high. Conversely, if the α-olefin content is too high, the amorphousness of the EOR is too high. (Reduced crystallinity), releasability,
Problems tend to occur in the surface appearance.

In order to reduce the coefficient of linear expansion and improve the formability, talc is added to the composition in an amount of 5 to 2%.
It is desirable to add 0 phr (preferably 8 to 15 phr).

If the talc is less than 5 phr, the above effects are difficult to obtain, and if the talc exceeds 20 phr, the flexural modulus is 10%.
It is difficult to obtain one at or below 00 MPa.

(6) Using the above-mentioned TPO composition, a long injection molded product such as a side molding is injection-molded.

The injection molding conditions at this time are as follows: cylinder temperature: 190 to 240 ° C., mold temperature: 20 to 50 ° C., injection pressure: 40 to 100 MPa.

The design surface of the injection molded article is a painted surface. As the paint used, for example, a urethane-based paint excellent in weather resistance and scratch resistance is used. The coating thickness is usually 15 to
80 μm. Usually, a finished coating film is formed after the application of the primer.

Particularly, in the side molding, the coating thickness is desirably 40 to 60 μm so that the coating does not peel off due to a door collision or the like.

[0043]

As described above, the TPO composition of the present invention comprises:
By blending specific PP, specific EPR and specific EOR at a predetermined ratio, flexural modulus and releasability, molded product appearance,
It is possible to mold a long injection molded product having a good balance of properties with the coating film adhesion.

When talc is added to the TPO composition, the talc acts as a lubricant to improve the releasability and appearance of the molded product, and to reduce the coefficient of linear expansion.

[0045]

[Test example]

(1) Hereinafter, in order to confirm the effects of the present invention, an example in which a comparative example is performed will be described.

Each TPO composition having the formulation shown in Tables 1 and 2 was
Using an injection molding machine, a test material (50 mm × 1200 mm × 2.5 mmt) was injection molded under the following molding conditions.

Molding condition A: cylinder temperature: 220 ° C., mold temperature: 30 ° C., injection pressure: 50 MPa Molding condition B: cylinder temperature: 220 ° C., mold temperature: 30
° C, injection pressure: 70 MPa, applied at the time of embossing on one side of 35 μm. The characteristics of each component used are those shown in Tables 3 to 5, respectively.

(2) The following test items and specifications were performed using the test materials.

Flexural modulus: Test piece under molding condition A (width:
12.6mm x thickness: 6.4mm x span length: 100mm)
Was performed based on ASTM-D790 at a bending test speed of 2 mm / min and a test temperature of 23 ° C.

Linear expansion coefficient: A test piece having a molding condition A of 3 mm × 3 mm × 10 mm was cut from the center of a JIS No. 1 dumbbell in parallel with the length direction of the dumbbell piece, and -10 to 80 ° C.
Of the dimensional change in the temperature range of
5000 (manufactured by Seiko Denshi Co., Ltd.).

Moldability (Releaseability): Under molding condition B, side molding (thickness: 2.8 mm, width: 65 mm, length: 120)
(0 mm, design surface: mirror polished) was molded by a vertical injection molding machine, and then the releasability when the molded product in the cavity was pushed up by an ejector pin was determined according to the following criteria.

：: The molded product is released without resistance and does not deform.

Δ: The molded product has a large release resistance due to sticking to the cavity or the like, and is deformed.

Appearance of molded article: The appearance of the side molding obtained above was visually judged according to the following criteria for the presence or absence of abnormal “flow marks and other surface irregularities”.

[0055] ○: abnormalities observed not, X: abnormal recognized <br/> et al is Ru.

Coating adhesion: After washing the side molding obtained above with isopropyl alcohol (IPA), chlorinated P
After application of the P-based primer, a finish coating was performed with an acrylic urethane-based paint, followed by baking and drying (100 ° C. × 30 minutes).

Then, after the initial product and the hot water test (40 ° C. ×
The test pieces (10 days) were subjected to the Goban test (JIS K 5400), and the test pieces after the hot water test were visually judged for the presence of blisters and the like.

In the goban test, the number of peeled squares out of the 100 squares is counted. That is, 60/10
0 indicates that 60 of the 100 cells were peeled off, and only 0/100 was accepted.

(3) The test results are shown in Tables 1 and 2. The injection molded product of each of the examples satisfying the requirements of the present invention has a balance between the flexural modulus and linear expansion coefficient and the molded product appearance and coating film adhesion, and particularly, the balance between the flexural modulus and scratch resistance. It can be seen that the sample exhibits physical properties. On the other hand, it can be seen that a molded article made of the composition of each comparative example does not have a balance between these properties.

[0060]

[Table 1]

[0061]

[Table 2]

[0062]

[Table 3]

[0063]

[Table 4]

[0064]

[Table 5]

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 23/00-23/36

Claims (5)

(57) [Claims] 1. A polyolefin-based elastomer composition used for molding a coated long injection molded article having a flexural modulus of 1000 MPa or less, wherein substantially a base polymer is crystalline polypropylene (hereinafter referred to as “crystalline PP”). ) As a hard phase component, an amorphous ethylene-propylene-based copolymer (hereinafter referred to as “EPR”) and an amorphous ethylene-α-olefin (C4 to C1).
2) A polymer alloy comprising a soft copolymer as a soft phase component (hereinafter referred to as “EOR”), wherein the blend ratio of the hard phase component and the soft phase component is the former / the latter (weight ratio) = 48 / 52-67 / 33, and the blend ratio of EPR and EOR is
The latter (weight ratio) = 1/9 to 9/1, and the properties of the crystalline PP are as follows: Q value (M _w / M _n ) ≧ 10, M
FR (230 ° C, 2.16 kgf / cm ² ) : 50 to 12
0, the Mooney viscosity of the EPR (ML _{1 + 4} 100 ° C.) 3 to 3
5 wherein the specific gravity of the EOR is 0.892 or less. 2. A composition comprising a polymer alloy comprising crystalline PP as a hard phase component and EPR and EOR as a soft phase component and a substantial base polymer, wherein the blend of the hard phase component and the soft phase component is provided. The ratio is the former / the latter (weight ratio) = 48/52 to 67/33, and the blend ratio of the EPR and EOR is the former / the latter.
The latter (weight ratio) = 1/9 to 9/1, and the properties of the crystalline PP are as follows: Q value (M _w / M _n ) ≧ 10, M
FR (230 ° C, 2.16 kgf / cm ² ) : 50 to 12
0, ethylene content: 2 to 12 wt%, and the characteristics of the EPR are propylene content: 20 to 45 wt%.
%, Mooney viscosity (ML _{1 + 4} 100 ° C.): 3 to 35, and the characteristic of the EOR is specific gravity: 0.870 to 0.892,
The polyolefin-based elastomer composition having an α-olefin content of 10 to 22% by weight. 3. The method according to claim 1, wherein the talc is 5 to 20 p.
A polyolefin-based elastomer composition having a composition blended with an hr. 4. The method according to claim 2, wherein the talc is 5 to 20 p.
A polyolefin-based elastomer composition having a composition blended with an hr. 5. A molded article obtained by injection molding from the polyolefin-based elastomer composition according to claim 1, wherein at least the design surface of the molded article is a painted surface. Long injection molded products.