Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2000-09-15
2002-02-12
Yoon, Tae H. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C526S348000, C526S351000
Reexamination Certificate
active
06346580
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thermoplastic resin composition having a good balance in rigidity, toughness and flowability.
2. Description of the Related Art
A propylene-based resin has been widely used as materials for an automobile and the like, because it is excellent in hardness, thermal resistance and the like, can be easily molded to an arbitrary form by a method such as an injection molding, an extrusion molding or the like, and is not expensive in cost, etc.
It has been recently desired to integrally mold a large size molded article such as, for example, a bumper or the like and to thin the thickness thereof for light weight. The improvement of flowability, rigidity, and toughness such as tensile elongation or the like is required for realizing it.
When the flowability is increased by adding a component such as a mineral oil, having a lower melting point than a resin, the hardness and thermal resistance which the propylene-based resin inherently has are lowered. When the flowability is increased by lowering the molecular weight of a resin, the resin becomes brittle and inferior in tensile elongation, etc. It is well known to add an ethylene-propylene copolymer rubber and the like in order to maintain the tensile elongation, etc., but the rigidity of the resin is largely lowered.
Therefore, the balance in rigidity, tensile elongation and flowability of the propylene-based resin has not enough satisfied needs in market.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a propylene-based resin composition having a good balance in flowability, rigidity and tensile elongation.
Namely, the present invention provides to a thermoplastic resin composition comprising 5 to 50% by weight of a propylene homopolymer(A) having an intrinsic viscosity measured in a tetralin solution at 135° C. of 1.2 dl/g or more, having a boiling heptane-insoluble portion content of 5.0 to 50.0% by weight and having an intrinsic viscosity measure in a tetralin solution at 135° C. of the boiling heptane-insoluble portion of 4.3 dl/g or less, and 95 to 50% by weight of a propylene-based resin(B) consisting of a propylene homopolymer(B1) having an isotactic pentad fraction of 0.970 or more or a composition consisting of at least 65% by weight of the propylene homopolymer(B1) and up to 35% by weight of an ethylene-propylene random copolymer(B2), the total of (A) and (B) being 100% by weight.
The present invention is illustrated in detail below.
DETAILED DESCRIPTION OF THE INVENTION
(A) Propylene homopolymer
The propylene homopolymer (A) used in the present invention has an intrinsic viscosity measured in tetralin at 135° C. of 1.2 dl/g or more, preferably 1.3 to 3.5 dl/g and more preferably 1.5 to 3.0 dl/g. When the intrinsic viscosity is within the range, it is preferable because a thermoplastic resin composition excellent in tensile elongation can be obtained.
The propylene homopolymer (A) contains a boiling heptane-insoluble portion of 5.0 to 50.0% by weight, and preferably 5.0 to 40.0% by weight. When the content is within the range, it is preferable because a thermoplastic resin composition having a good balance between rigidity and tensile elongation can be obtained.
The propylene homopolymer (A) has an intrinsic viscosity measured in tetralin at 135° C. of the boiling heptane-insoluble portion of 4.3 dl/g or less, and preferably 2.5 to 4.0 dl/g. When the intrinsic viscosity is within the range, it is preferable because a thermoplastic resin composition excellent in tensile elongation and flowability can be obtained.
The melting point of the propylene homopolymer (A) is not particularly limited, and 140 to 155° C. is preferable and 145 to 155° C. is more preferable. When the melting point is within the above range, it is preferable because a thermoplastic resin composition having a good balance between rigidity and tensile elongation can be obtained.
Further, there is no specific limitation concerning the isotactic pentad fraction of the propylene homopolymer (A), and 0.300-0.800 is preferable, 0.320-0.750 is more preferable and 0.320-0.700 is further preferable. When the isotactic pentad fraction is within the above range, it is preferable because a thermoplastic resin composition having a good balance between rigidity and tensile elongation can be obtained.
Herein, the isotactic pentad fraction is the fraction of isotactic chains having pentad units in a propylene polymer molecular chain measured by using the method published in Macromolecules, vol.6, 925(1973) by A.Zambelli et al, that is, by using
13
C-NMR, and in other words, the fraction of propylene monomer units being at the center of a chain wherein five propylene monomer units are consecutively meso-bonded. Herein, the assignment of NMR absorption peaks is determined in accordance with Macromolecules, Vol.8, 687(1975) published thereafter.
The content of the 20° C. xylene-soluble portion of the propylene homopolymer (A) is not particularly limited, and 20 to 80% by weight is preferable and 35 to 80% by weight is more preferable. When the content is within the above range, it is preferable because a thermoplastic resin composition having a good balance in rigidity and tensile elongation can be obtained.
The propylene homopolymer (A) can be obtained, for example, by homopolymerizing propylene in the presence of a polymerization catalyst obtained by bringing a metallocene compound represented by the general formula [I] described below, into contact with an activating co-catalyst:
wherein each of R
1
to R
22
is independently a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an aralkyl group or a substituted silyl group, R
1
to R
22
may be mutually the same or different, and arbitrary two adjacent R
1
to R
22
which are in the same ring may form a ring of 5 to 8 carbon atoms, M is a transition metal atom of the IV Group of the Periodic Table of Element, X is a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an aralkyl group or an alkoxy group, and two X's may be the same or different.
In the metallocene compound represented by the above-mentioned general formula [I], M represents a transition metal atom of the IV Group of the Periodic Table of Element (IUPAC Inorganic Chemistry Nomenclature: Revised Edition 1989), and a titanium atom, a zirconium atom or a hafnium atom is preferable and in particular, a zirconium atom is preferable.
The halogen atom in the substituents, R
1
to R
22
, or X includes a fluorine atom, a chlorine atom and an iodine atom, and in particular, a fluorine atom is preferable.
The alkyl group in the substituents, R
1
to R
22
, or X preferably includes an alkyl group having 1 to 20 carbon atoms. Examples thereof include a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, a sec-butyl group, a tert-butyl group, an isobutyl group, a n-pentyl group, a neopentyl group, a n-hexyl group, a n-octyl group, a n-decyl group, a n-dodecyl group, a n-pentadecyl group, a n-eicosyl group and the like, and a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, an isobutyl group or a n-pentyl group is more preferable.
All of these alkyl groups may be substituted with a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or an iodine atom. Examples of the alkyl group having 1 to 10 carbon atoms which is substituted with the halogen atom include a fluoromethyl group, a trifluoromethyl group, a chloromethyl group, a trichloromethyl group, a fluoroethyl group, a pentafluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluorohexyl group, a perfluorooctyl group, a perchloropropyl group, a perchlorobutyl group, a perbromopropyl group and the like.
Further, all of these alkyl groups may be partially substituted with an alkoxy group such as a methoxy group, an ethoxy group or the like, an aryloxy group such as a phenoxy group or the like or an aralkyloxy group such as a benzyloxy group or the like, etc.
As the aryl gr
Atarashi Kenji
Fujita Masayuki
Fitch Even Tabin & Flannery
Sumitomo Chemical Co,. Ltd.
Yoon Tae H.
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