Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1997-09-12
1999-07-13
Wilson, Donald R.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
428 352, 428 369, 428220, C08L 2320
Patent
active
059228121
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to a 4-methyl-1-pentene polymer composition, and more specifically, to a 4-methyl-1-pentene polymer composition having excellent heat sealability and mechanical properties.
BACKGROUND TECHNOLOGY
4-methyl-1-pentene polymers are widely used in such applications as MWO food containers, syringes, analysis cells, experimental equipment such as beakers and flasks, base material used in preparing synthetic leathers in view of their high transparency and high melting point in the range of from 220 to 240.degree. C. and the resulting high heat distortion temperature. The 4-methyl-1-pentene polymers, however, were sometimes insufficient in other mechanical properties such as impact resistance, and the films made therefrom had insufficient heat sealability. A widely adopted solution for improving such insufficient heat sealability is addition of a low density polyethylene, an ethylene-propylene copolymer, or other ethylene-based resins. Such addition of the ethylene-based resin to the 4-methyl-1-pentene polymers have so far resulted in little improvement in their heat sealability, and instead, resulted in poor dispersion and deteriorated impact resistance. Another means proposed for improving the heat sealability of the films made from 4-methyl-1-pentene polymers is addition to the 4-methyl-1-pentene polymers of a particular propylene-.alpha.-olefin copolymer (JP-A-60-28442).
The films prepared by blending the 4-methyl-1-pentene polymers with the particular propylene-.alpha.-olefin copolymer were still insufficient both in their heat seal strength and improvement in mechanical properties. In view of such situation, there is a strong demand for a 4-methyl-1-pentene polymer composition which has improved heat sealability and mechanical properties while retaining the characteristic features of the 4-methyl-1-pentene polymer.
SUMMARY OF THE INVENTION
In view of such situation, an object of the present invention is to provide a 4-methyl-1-pentene polymer composition wherein excellent heat resistance, releasability, gas permeability, and other properties inherent to the 4-methyl-1-pentene polymers are retained, and wherein impact resistance and other mechanical properties as well as heat sealability are improved.
To obviate such problems, the inventors of the present invention have made extensive studies in order to make use of characteristic features of the 4-methyl-1-pentene polymer and to improve the heat sealability and impact resistance. After such efforts, the inventors found that the mechanical properties and heat sealability can be markedly improved when the 4-methyl-1-pentene polymer is blended with a 1-butene polymer and a propylene polymer, and the present invention has been completed on such finding.
According to the present invention, there is provided a 4-methyl-1-pentene polymer composition prepared by melt mixing 40 to 97.5 parts by weight of a 4-methyl-1-pentene polymer (A), 2.5 to 60 parts by weight of a 1-butene polymer (B), and 1 to 100 parts by weight, based on 100 parts by weight of the total of (A) and (B), of a propylene polymer (C).
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the 4-methyl-1-pentene polymer composition of the present invention (hereinafter referred to as "the composition of the present invention") is described in detail.
The 4-methyl-1-pentene polymer used as component (A) in the composition of the present invention is either a 4-methyl-1-pentene homopolymer or a random copolymer of the 4-methyl-1-pentene with another .alpha.-olefin. Exemplary such .alpha.-olefins include .alpha.-olefins containing 2 to 20 carbon atoms such as ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. When such an .alpha.-olefin is contained in the 4-methyl-1-pentene polymer (A), it may be contained either alone or in combination of two or more. Among such .alpha.-olefins, the preferred are 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene.
REFERENCES:
patent: 4546150 (1985-10-01), Shigemoto
patent: 5534593 (1996-07-01), Friedman
Kan Kojiro
Yamamoto Akio
Mitsui Chemicals Inc.
Wilson Donald R.
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