Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2002-02-13
2003-07-01
Niland, Patrick D. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C523S217000, C524S493000, C524S502000, C524S504000, C524S847000
Reexamination Certificate
active
06586517
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a long fiber-reinforced polypropylene resin composition for a molded article which is improved in all of a mechanical strength, a rigidity and an impact resistance as compared with those of conventional ones and which is excellent as well in a durability.
BACKGROUND OF THE INVENTION
A so-called long fiber-reinforced polypropylene resin composition obtained by impregnating a molten polypropylene resin on a continuous fiber bundle for reinforcement and then carrying out a pulltrusion, followed by cutting it to a pellet having a length of 2 to 50 mm provides a molded article which is excellent in a mechanical strength, a rigidity and an impact resistance and therefore is widely used for uses in car parts, industrial parts and the like. However, the existing state is that all of these items are still unsatisfactory depending on uses and desired to be further improved.
A composition obtained by impregnating a modified polyolefin blended with an alkaline earth metal compound on a reinforced fiber bundle and then cutting it to a pellet was filed in International Publication WO99/20446 as international application for patent by the present applicants as a long fiber-reinforced polyolefin resin composition for a molded article which is improved in a mechanical strength and an impact resistance. This composition is satisfactory in a mechanical strength and an Izod impact strength but still unsatisfactory in a punching impact resistance and a durability.
Further, compositions prepared by blending long fiber-reinforced polypropylene polymer pellets with propylene-ethylene block copolymers are proposed as a glass fiber-reinforced polyolefin resin composition which is improved in a mechanical strength and an impact resistance (Japanese Patent Application Laid-Open No. 239286/1993 and Japanese Patent Application Laid-Open No. 173329/1995). These compositions are improved as well in a mechanical strength and an Izod impact strength but still unsatisfactory in a rigidity, a punching impact resistance and a durability.
As described above, a long fiber-reinforced polypropylene resin composition for a molded article which is improved in all of a mechanical strength, a rigidity, an impact resistance and specifically a punching impact resistance to a large extent and which is excellent as well in a durability has not yet been known, and such composition has been desired.
An object of the present invention is to solve the problems described above and to provide a long fiber-reinforced polypropylene resin composition which is more improved in all of a mechanical strength, a rigidity and an impact resistance than those of conventional ones and is excellent as well in a durability and which can suitably be used for wide applications.
SUMMARY OF THE INVENTION
Intensive investigations repeated by the present inventors in order to obtain a long fiber-reinforced polypropylene resin composition which can solve the problems described above. They have resulted in finding that very effective for solving the problems described above is a resin composition obtained by blending a long fiber-reinforced resin comprising as a base and a specific modified propylene polymer compounded with an alkaline earth metal compound with a specific crystalline propylene-ethylene copolymer as a diluent, and thus they have reached the present invention.
That is, the present invention comprises structures shown below.
The present invention relates to a long fiber-reinforced polypropylene resin composition comprising a long fiber-reinforced-propylene polymer composition (A) and a crystalline propylene-ethylene copolymer composition (B), wherein the former accounts for 55 to 90% by weight, and the latter accounts for 10 to 45% by weight.
The long fiber-reinforced propylene polymer composition (A) of the former comprises (A1), (A2) and (A3) shown below, and the blending proportions thereof are 20 to 64.9% by weight, 0.1 to 5% by weight and 35 to 75% by weight respectively;
(A1): a modified propylene polymer obtained by modifying a propylene homopolymer with an unsaturated carboxylic acid or an anhydride thereof, or a mixture of the above modified propylene polymer and an unmodified propylene homopolymer, wherein the isotactic pentad ratio (P value) is 96% or more, and the melt flow rate (230° C., 21.18N; hereinafter abbreviated as ┌MFR┘) is 100 to 500 g/10 min,
(A2): at least one selected from the group consisting of simple substances, hydroxides and oxides of alkaline earth metals and
(A3): a long glass fiber having a length of 2 to 50 mm.
The crystalline propylene-ethylene copolymer composition (B) of the latter is a composition comprising (B1) and (B2) shown below in which the mixing proportion thereof is 0.001 to 1 part by weight of (B2) per 100 parts by weight of (B1);
(B1): 100 parts by weight of a crystalline propylene-ethylene copolymer having an MFR of 10 to 60 g/10 min comprising a propylene homopolymer part which is a polymer having an isotactic pentad ratio (P value) of 96% or more, a ratio (Q value) of a weight average molecular weight (Mw) to a number average molecular weight (Mn) being 6 or less and a hexane extract content of 0.8% by weight or less, and a propylene-ethylene copolymer part and
(B2): 0.01 to 1 part by weight of a nucleating agent.
The preferred embodiment of the present invention is the resin composition described above, wherein the modified propylene polymer or the mixture of the above modified propylene polymer and the unmodified propylene homopolymer (A1) has an MFR of 100 g/10 min or more and less than 300 g/10 min.
Another preferred embodiment of the present invention is the resin composition described above, wherein the propylene homopolymer part (B1) contained in the crystalline propylene-ethylene copolymer has an isotactic pentad ratio (P value) of 97% or more.
More preferred embodiment of the present invention is the resin composition described above, wherein the long fiber-reinforced propylene polymer composition (A) is a pellet produced by a melt-pulltrusion method.
Further preferred embodiment of the present invention is the resin composition described above, wherein the unsaturated carboxylic acid or anhydride thereof is maleic anhydride.
Further preferred embodiment of the present invention is the resin composition described above, wherein at least one selected from the group consisting of simple substances, hydroxides and oxides of alkaline earth metals is magnesium hydroxide.
DETAILED DESCRIPTION OF THE INVENTION
The modified propylene polymer (A1) obtained by modifying a propylene homopolymer with unsaturated carboxylic acid or an anhydride thereof, or the mixture of the above modified propylene polymer and an unmodified propylene homopolymer constituting the long fiber-reinforced propylene polymer composition (A) according to the present invention has to have an isotactic pentad ratio (P value) of 96% or more and an MFR of 100 to 500 g/10 min, preferably 100 g/10 min or more and less than 300 g/10 min in terms of an improving effect for the rigidity, the impact resistance and the durability. Also when (A1) is the mixture of the modified propylene polymer and the unmodified propylene homopolymer, the mixture has to fall in the range described above. However, it is more preferred in terms of an improving effect for the rigidity, the impact resistance and the durability that the unmodified propylene homopolymer is not used and the substantially whole amount of (A1) is the modified propylene polymer.
In this case, the isotactic pentad ratio shows an isotactic ratio in terms of a pentad unit in a molecular chain and can be determined based on the descriptions of Macromolecules 8, 687 (1975) by means of
13
C-NMR.
A production process for the modified propylene homopolymer described above includes a process in which 100 parts by weight of a propylene homopolymer having an isotactic pentad ratio of 96% or more is molten and kneaded with 0.1 to 5 parts by weight of an unsaturated carboxylic acid or a derivative thereof and 0.0
Nakai Toshimori
Saito Koichi
Tochioka Takahiro
Mazda Motor Corporation
Niland Patrick D.
Wenderoth , Lind & Ponack, L.L.P.
LandOfFree
Long fiber-reinforced polypropylene resin composition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Long fiber-reinforced polypropylene resin composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Long fiber-reinforced polypropylene resin composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3040910