JPH0229443A - Flexible polyolefin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent in, especially, rigidity at high temperatures and scratch resistance by mixing a crystalline propylene polymer, an ethylene/propylene/(diene) copolymer rubber, a specified propylene/alpha- olefin copolymer rubber and a specified ethylene/alpha-olefin copolymer together. CONSTITUTION:This composition is prepared from 20-79wt.% crystalline propylene polymer of an alpha-olefin (e.g., ethylene) content of, desirably, 3-25wt.%, 5-30wt.% ethylene/propylene/(diene) copolymer rubber of a Mooney viscosity of, desirably, 50-100, which is a copolymer of propylene with a diene (e.g., ethylidenenorbornene) of an ethylene content of, desirably, 50-70%, 10-50wt.% copolymer rubber of a Mooney viscosity of 30-100, comprising propylene and another alpha-olefin (e.g., ethylene in a content of 20-50%) and 5-30wt.% copolymer of ethylene with an alpha-olefin (a content of, desirably, 1-30mol%) (e.g., propylene) having a density of 0.860-0.930g/cm<3>, a boiling n-hexane-insoluble content of 10wt.%, and a max peak temperature in differential scanning calorimetry >=100 deg.C.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a moldable soft polyolefin composition useful for industrial applications such as automobile parts, and more particularly, to a moldable flexible polyolefin composition that is highly flexible, has high impact resistance, and is moldable. The present invention relates to a flexible polyolefin composition for molding that has excellent properties and appearance of molded products, has good heat resistance, and is easy to bake and coat.

(Prior Art) Conventionally, polyolefin-based thermoplastic elastomers (hereinafter referred to as TPO) have low specific gravity, excellent chemical resistance, weather resistance, and ozone resistance, and relatively low physical properties such as rigidity and impact resistance. It is used in various fields because of its good quality and low price.

-i, TPO is crystalline polypropylene (hereinafter referred to as PP
) and polyethylene as hard segments, and olefin elastomers such as ethylene-propylene rubber (hereinafter referred to as EPR), polyisobutylene, and polybutadiene as soft segments, and are partially crosslinked to improve physical properties. is also often done.

However, in recent years, as TPO has been used in industrial fields, particularly in automobile parts, the required performance has become more diverse. In other words, for example, when it comes to automobile exterior materials, not only are moldability, good appearance of the molded product, and impact resistance required, but also good paintability is required for the parts to be painted, and furthermore, good paintability is required for the unpainted parts. now requires scratch resistance.

Note that paintability requires not only high adhesion strength of the coating film, but also high rigidity at high temperatures so that the molded product does not deform when baking the coating film. Therefore, compositions containing a large amount of rubber in order to provide flexibility are required to have high high-temperature rigidity since the molded product is easily deformed, especially during baking painting.

(Problem to be Solved by the Invention) However, conventional TPO cannot meet such requirements, and therefore, for example, Japanese Patent Laid-Open No. 54-41950 discloses that the density of pp and EPR is 0.915 to 0. .97g
A composition obtained by kneading polyethylene/cm3 and peroxide has been proposed, but it does not have sufficient moldability or impact resistance.

Moreover, PP, 1!
: Composition of EPR and medium-density polyethylene, JP-A-5
7-159841 discloses a composition of PP, EPR, high-density polyethylene, and talc, and JP-A-58-2643 and JP-A-5880335 disclose a composition of PP, EPR, and an ethylene-α-olefin linear composition. Compositions with polymers have been proposed, but these have problems in that they still have insufficient scratch resistance and rigidity at high temperatures.

(Means for Solving the Problems) As a result of intensive research in order to solve the above-mentioned problems related to TPO based on pp and EPR, the present inventors found that a specific propylene and other α-olefin copolymer rubber The present inventors have discovered that the above problems can be solved by further blending ethylene-α-olefin copolymers and the like, and have completed the present invention.

Therefore, the flexible polypropylene composition of the present invention comprises (a)
20 to 70% by weight of a crystalline propylene polymer; (b) 10 to 50% by weight of propylene and other α-olefin copolymer rubber having a Mooney viscosity of 30 to 100; and (c) ethylene-propylene copolymer rubber or ethylene. - 5 to 30% by weight of propylene-diene copolymer rubber and (d) a density of 0
．． Boiling at 860-0.930 g/am3, hexane solubles are 10% by weight, differential scanning calorimetry (DSC)
It is characterized by containing 5 to 30% by weight of an ethylene-α-olefin copolymer having a maximum peak temperature of 100°C or higher.

Next, the components to be added to the polyolefin composition of the present invention will be explained.

First, component (a) PP is isotactic or gingiotactic PP with a high degree of crystallinity, especially propylene and small amounts of other α-olefins, such as ethylene, butene-1, hexene-1,4 =Methylpentene-
A block copolymer (hereinafter referred to as block PP) with PP 1 or the like is preferred.

The content of α-olefin is preferably in the range of 3 to 25% by weight, and if the content of α-olefin is less than 3% by weight, the impact resistance of the composition may be insufficient.
If it exceeds % by weight, heat resistance may deteriorate, which is not preferable. In addition, it is preferable that the melt flow rate (hereinafter referred to as MFR) of the PP to be blended is 1 to 100 g/10 minutes, and ■If PP is blended with a PR of 1 g/10 minutes or less, the moldability of the composition will be adversely affected. This is undesirable as it may affect the appearance of the product.

The blending amount of component (a) is 20 to 70% by weight, preferably 30 to 60% by weight. If the amount is less than 20% by weight, the heat resistance of the composition will be insufficient, and if it exceeds 70% by weight, impact resistance, paintability, flexibility, etc. will be insufficient, which is not preferable.

(b) Mooney viscosity of component (ML+ $4 (+..)
) is 30 to 100, propylene and other α-olefin copolymer rubbers have an ethylene content of 20 to 50% by weight.
, preferably 25 to 40% by weight propylene-ethylene copolymer rubber (hereinafter referred to as PP rubber).

This PP rubber is widely used as a rubber for reasons such as weather resistance, chemical resistance, heat resistance, and moldability.
PR has a high ethylene content of 50 to 75% by weight, whereas PR has a low ethylene content. If PP rubber with an ethylene content of more than 50% by weight is blended, the modulus of elasticity at high temperatures will be small, making it inconvenient for painting and resulting in a composition with poor scratch resistance. It is not preferable to use less PP rubber because the coating film adhesion and solvent resistance of the composition will be insufficient.

Note that component (b) is blended in an amount of 10 to 50% by weight.

If the amount is less than 10% by weight, the composition will have poor impact resistance and scratch resistance, and if it exceeds 50% by weight, moldability will decrease and a molded product with poor appearance will be obtained.

(c) Component EPR or ethylene-propylene-diene copolymer rubber (hereinafter referred to as EPDM) has an ethylene content of 50 to 75% by weight, and is a di- or ternary copolymer rubber with propylene or butene-1 and diene. It is a polymer rubber. As the diene, ethylidene norbornene, dicyclopentadiene 1,4-hexadiene, etc. are used. The Mooney viscosity of this EPR or EPDM is preferably about 50 to 100. If the Mooney viscosity is less than 50, the impact resistance will decrease, and if it exceeds 100, the moldability may decrease, which is not preferred.

The blending amount of the component (c) is 5 to 30% by weight. If the amount is less than 5% by weight, the impact resistance of the composition will be insufficient, and if it exceeds 30% by weight, the moldability will decrease and a composition with poor appearance will be obtained, which is not preferable.

The ethylene-α-olefin copolymer of component (d) is a copolymer of ethylene and carbon atoms having 3 to 12 carbon atoms, and the α-olefins include propylene, butene-1, 4-methylpentene-1, hexene-1, 1, octene-1, etc. can be exemplified. In addition, the content of the above α-olefin is 1 to
It is in the range of 30 mol%.

This ethylene-α-olefin copolymer (d) has a density of 0.860 to 0.930 g/cm', a boiling n-hexane insoluble content of 10% by weight or more, and a differential scanning calorimetry (D
The maximum peak temperature indicated by SC) must be 100'C or higher. Density is 0.860 g/r
: less than m3 and the maximum peak temperature indicated by OSC is 100
If a material with a density of less than 'C' is blended, a composition with insufficient heat resistance will be produced. On the other hand, if a density is greater than 0.930 g/cm', a composition with poor impact resistance will be produced.

The method for measuring the boiling n-hexane insoluble matter and DSC is as follows.

<Method for measuring insoluble content in boiling n-hexane> A sheet with a thickness of 200 μm is formed using a hot futon, and
Cut out three sheets of 0mIT+×30M, and boil the sheets using a double-tube Soxhlet extractor.
- No hexane? After extracting the volume and drying under vacuum at 50°C for 7 hours, the n-hexane insoluble content is calculated using the following formula.

n-hexane insoluble content (wt%) - <OSC measurement method> Approximately 5
Weigh out mg of the sample, set it in a differential scanning calorimeter, raise the temperature to 170°C, hold at that temperature for 15 minutes, and then cool down to 0°C at a cooling rate of 2.5°C/min. do. Next, from this state, increase the temperature to 170°C at a rate of 10°C/min.
Measurement is performed by raising the temperature to . The temperature at the top position of the maximum peak that appears between 0°C and 170°C is determined.

, MFR (190°C) of jD(d) component is 0.1 to 3
Preferably it is 0 g/10 minutes. MFR is 0.1
If it is less than 30 g/10 minutes, the fluidity of the composition may decrease, and if it exceeds 30 g/10 minutes, a composition with poor impact resistance may be produced, which is not preferable.

The blending amount of component (d) is 5 to 30% by weight. If the amount is less than 5% by weight, the moldability of the composition and the gloss of the molded product will not improve, and if it is more than 30% by weight, the heat resistance will be insufficient, which is not preferable.

In addition, in the composition of the present invention, the above-mentioned resin content is 100
0 to 100 M parts of inorganic filler can be blended with respect to parts by weight.

The above-mentioned fillers include calcium sulfate, calcium silicate, clay, diatomaceous earth, and alumina outside the barrel.

Silica sand, glass powder, iron oxide, metal powder, graphite.

Silicon carbide, silicon nitride, silica, boron nitride, aluminum nitride, carbon black, mica, glass plate, sericite, pyrophyllite, aluminum flake, shirasu balloon, metal balloon, glass balloon, pumice, glass fiber, carbon fiber, graphite Examples include fiber, Fisker, metal fiber, silicon carbide fiber, asbestos, and wollastonite.

If the blending amount of the filler exceeds 100 parts by weight, it is not preferable because the impact strength of the molded product decreases.

In addition, stearic acid is added to the surface of the inorganic filler.

It is preferable to perform the surface treatment using oleic acid, palmitic acid or a metal salt thereof, paraffin wax, polyethylene wax or a modified product thereof, organic silane, organic poran, organic titanate, or the like.

Furthermore, the composition of the present invention may contain other thermoplastic resins, other rubbers, antioxidants, or stabilizers as required.

UV absorbers, dyes or pigments, antistatic agents.

A flame retardant, a nucleating agent (crystallization accelerator), a lubricant, a mold release agent, etc. can be added. Also, several types may be combined.

The method for producing the plastic material of the present invention is not particularly limited, and for example, the plastic material of the present invention can be produced by melt-kneading with an open roll, a pressure kneader, a Banbury mixer, or the like. However, these are generally batch operations and have poor productivity, so a method using an extruder is preferred. As the extruder, a full-flight screw extruder may be used, but since kneading may be insufficient, it is preferable to use an extruder having a kneading zone or a twin-screw extruder.

Also, when kneading, it is also possible to knead all the ingredients at the same time.
It is also possible to knead the three components in advance and then add and knead the remaining components.

(Function) In the plastic material of the present invention, since each component acts in a complex manner, it is difficult to discuss the mechanism of action of each component, but it is generally inferred as follows.

Component (a) PP contributes to heat resistance, gloss, and moldability, component (b) PP rubber contributes to impact resistance, scratch resistance, flexibility, and paintability; ) component EPR
Or EPDM contributes to flexibility and impact resistance, (d
It is thought that the ethylene-α-olefin copolymer of component ) contributes to improving gloss and moldability.

(Effects of the Invention) As explained above, the composition of the present invention comprises a specific amount of crystalline propylene polymer and a Mooney viscosity of 30 to 100.
Because it is a blend of propylene, other α-olefin copolymer rubber, ethylene-propylene copolymer rubber, or ethylene-propylene-diene copolymer rubber and ethylene-α-olefin copolymer, it is thermoplastic with flexibility. Not only can the resin be more suitably used in fields where conventional TPO has been used, but it can also be used in automobile exterior materials, etc., which could not be used in the past.

That is, exterior materials such as bumpers and spoilers are required to have not only impact resistance, surface gloss, moldability, and flexibility, but also materials with excellent rigidity and scratch resistance at high temperatures. Depending on the product, it is possible to provide a material that satisfies all of these requirements.

(Examples) The present invention will be described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

The physical properties of the test pieces produced on each side were evaluated using the test method shown below.

(Test method) ■MFR: According to JIS K6758 (measurement temperature 2
30”C).

■Tensile yield point strength: Based on ASTM D638.

■Bending elastic modulus: Based on ASTM D790.

■Izot impact value 2 According to ASTM D259.

■Deflection temperature under load: According to ASTM D648.

■Glossiness: JIS K7105 (60"-60'
)by.

■Scratch resistance: 100 x 20 with the following car wash brush tester
A 0 mm injection molded plate was brushed for 1 minute, and if the glossiness retention rate after the test was 172 or less than before the test, it was determined to be poor (X), and if it was 1/2 or more, it was determined to be good (0).

*Nylon strands are densely embedded in the cylinder of the car wash brush tester.
A device that rubs the molded plate as it rotates. 3
017mln of water is showered.

Radius of cylinder: Length of 57 cylinder + 297 mm Distance between axis center and sample surface Wlil: 190 m + n
Brush rotation speed: 1420 rpm Next, the raw materials used on each side are listed together with the symbols used in Table 1.

(Raw materials) (a) Crystalline ethylene propylene polymer (PP)
No. MFR (g/10m1n) Ethylene content (wt%) A-1146.0 A-23612 (b) Propylene and other α-olefin copolymer rubber (
PP rubber) Symbol ML+ -loo (100°C
) Ethylene content (wt%) B-14623 B-27431 (c) Ethylene-propylene copolymer rubber or ethylene-propylene-diene copolymer rubber (εPR or EPDM
) C-182 f, -27I C-323 *Ethylidene norbornene (d) Special ethylene-α Olefin copolymer D-16,0 Propylene 0.915 9
0 122D-21,1 Butene-10,90
192121 Length 淘劃 [Side 2i Using the above raw materials, pre-mix in a Henschel mixer at the compounding ratio shown in Table 1, and mix in a 50 mm diameter kneading extruder (
Extrusion pellets were produced at 200°C using Nakatani Machinery (NCV-50).

The pellets were then heated to a temperature of 200"C and 10"C.
A test piece was prepared using an injection molding machine (L590 manufactured by Toshiba Machinery Co., Ltd.) at a pressure of 00 kg/cm.
Also listed in the table.

Comparative Flaming Test specimens were obtained by carrying out the same operations as in the example except that the formulations shown in Table 1 were used. A test similar to that in the example was conducted,
The obtained results are also listed in Table 1.

Claims (1)

[Claims] 1. (a) 20 to 70% by weight of crystalline propylene polymer
and (b) 10 to 50% by weight of propylene and other α-olefin copolymer rubber having a Mooney viscosity of 30 to 100 and (
c) 5 to 30% by weight of ethylene-propylene copolymer rubber or ethylene-propylene-diene copolymer rubber and (
d) Ethylene-α- having a density of 0.860 to 0.930 g/cm^3, a boiling n-hexane insoluble content of 10% by weight, and a maximum peak temperature of 100°C or higher as measured by differential scanning calorimetry (DSC). A flexible polyolefin composition characterized in that it contains 5 to 30% by weight of an olefin copolymer.