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
2000-03-29
2002-01-15
Nutter, Nathan M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S240000
Reexamination Certificate
active
06339128
ABSTRACT:
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a polyolefin resin modifier and, particularly, to a modifier effective in improving the film processability, stretchability and heat resistance such as low thermal shrinkage of a crystalline polyolefin resin used in an oriented film, for example, a polypropylene-based resin, a modified polyolefin resin composition and an oriented film formed from the resin composition.
An oriented polyolefin film, particularly a biaxially oriented polyolefin film is widely used as a packaging material and the like thanks to its excellent mechanical and optical properties. To produce the film, sequential biaxial orientation using a tenter system is generally employed.
In recent years, the production equipment of biaxially oriented polyolefin films has been becoming larger in size and higher in speed. When a biaxially oriented film is to be produced from a conventional general polyolefin resin with the equipment, such problems as a rise in mechanical load to a stretching machine, a reduction in the thickness accuracy of a film and the breakage of a film by stretching have arisen. Therefore, various methods for improving stretchability have been proposed. For example, JP-A 9-324014 (the term “JP- A” as used herein means an “unexamined published Japanese patent application”) proposes a technology in which an amorphous component is contained in a specific amount and an isotacticity distribution is made wide. However, there still remains room for the improvement of the obtained film to produce an oriented polyolefin film having excellent film formability at the time of high-speed film formation and excellent mechanical properties and heat resistance.
Therefore, the development of a polyolefin resin having excellent stretchability which can be produced with large-sized and high-speed oriented polyolefin film production equipment has been desired.
It is therefore an object of the present invention to provide a polyolefin resin composition which has a wide temperature control range for film formation at the time of stretching and a small mechanical load, is excellent in the thickness accuracy of the formed film and stretchability, can be produced stably without being broken by stretching or the like, and is suitable for the production of a uniaxially or biaxially oriented film having excellent heat resistance such as the thermal shrinkage of the formed film.
It is another object of the present invention to provide a polyolefin resin which can provide the above excellent characteristic properties to a polyolefin resin composition obtained by mixing a crystalline polyolefin resin and a modifier comprising the same.
It is still another object of the present invention to provide an oriented film formed from the above polyolefin resin composition of the present invention.
The other objects and advantages of the present invention will become apparent from the following description.
According to the present invention, firstly, the above objects and advantages of the present invention are attained by a crystalline polyolefin resin composition comprising:
(A1) 4 to 20 wt % of a polyolefin resin component having an elution temperature of 36 to 104° C. and a molecular weight of 100,000 to 1,000,000 measured by a direct coupling method (TREF/SEC) of size exclusion chromatography (SEC) to temperature rising elution fractionation (TREF); and
(B) 96 to 80 wt % of a crystalline polyolefin resin component different from the above component (A1), the wt % being based on the total of the components (A1) and the above (B).
According to the present invention, secondly, the above objects and advantages of the present invention are attained by an oriented film formed from the above crystalline polyolefin resin composition of the present invention.
According to the present invention, thirdly, the above objects and advantages of the present invention are attained by a modifier for a crystalline polyolefin resin comprising more than 20 wt % to 100 wt % of a component having an elution temperature of 36 to 104° C. and a molecular weight of 100,000 to 1,000,000 measured by the direct coupling method (TREF/SEC) of size exclusion chromatography (SEC) to temperature rising elution fractionation (TREF) and by a modifier comprising the same.
According to the present invention, fourthly, the above objects and advantages of the present invention are attained by a modifier for a crystalline polyolefin resin comprising 20 to 100 wt % of a component having an elution temperature of more than 116° C. and a molecular weight of 10,000 to 100,000 measured by the direct coupling method (TREF/SEC) of size exclusion chromatography (SEC) to temperature rising elution fractionation (TREF) and by a modifier comprising the same.
The present invention will be descried in detail hereinunder.
In the present invention, the direct coupling method (TREF/SBC) of size exclusion chromatography (SEC) to temperature rising elution fraction (TREF) is an analytical method which directly couples temperature rising elution fractionation (TREF) to size exclusion chromatography (SEC) on an on-line basis and will be simply referred to as “TREF/SEC” hereinafter. TREF/SEC is a method of evaluating the composition distribution of a polyolefin by dissolving the polyolefin (such as a polypropylene resin) crystallized in a solution in a solvent at different temperatures and continuously measuring the molecular weight distribution and the elution (concentration) of the polyolefin at each dissolution temperature. That is, an inert carrier such as diatomaceous earth or silica beads are used as a filler, a sample solution dissolved an amount of a polyolefin in a solvent such as orthodichlorobenzene as a sample is injected into the TREF column of the filler, the temperature of the TREF column is lowered to adhere the sample to the surface of the filler, the temperature of the column is elevated stepwise to a desired level, the orthodichlorobenzene solvent is passed through the column, the polyolefin component eluted at the above temperature is continuously introduced into a high-temperature SEC column, and the elution (wt %) and molecular weight distribution of the polyolefin are measured. The composition distribution of the polyolefin can be seen from a graph (the relationship between crystallizability and molecular weight is expressed by a contour or a bird's-eye view) drawn based on the elution temperature (° C.) and the molecular weight distribution of the polyolefin by this operation. A projection diagram of elution temperature shows a crystallizability distribution and the crystallinity distribution of the polymer can be obtained from the relationship between elution temperature and the elution (wt %) of a polymer because the elution temperature becomes higher as the elution component is crystallized more easily.
In the above method, the cooling rate of the TREF column must be adjusted to a speed required for the crystallization of a crystalline portion contained in the polyolefin sample at a predetermined temperature and can be determined experimentally in advance. The cooling rate of the column is generally set to a range of 5° C./min or less.
Crystalline Polyolefin Resin Composition
In the present invention, it is important that the component (A1) having an elution temperature of 36 to 104° C. and a molecular weight of 100,000 to 1,000,000 measured by TREF/SEC should be contained in the crystalline polyolefin resin composition in an amount of 4 to 20 wt %, preferably 5 to 18 wt %, more preferably 6 to 15 wt %. When the amount of the above effective component (A1) contained in the crystalline polyolefin resin composition is smaller than 4 wt %, stretchability at the time of film formation lowers, the range of film processable temperature narrows and a mechanical load rises, thereby increasing the breakage of a film by stretching and deteriorating the thickness accuracy of a film. When the amount of the above effective component (A1) is larger than 20 wt %, the thermal shrinkage of an oriented fi
Aoki Akira
Kaminaka Manabu
Masada Isao
Nakayama Nobuhiko
Birch & Stewart Kolasch & Birch, LLP
Idemitsu Petrochemical Co. Ltd.
Nutter Nathan M.
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