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
1999-09-20
2003-01-21
Acquah, Samuel A. (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...
C525S426000, C525S535000, C525S540000, C528S310000, C528S373000, C528S401000
Reexamination Certificate
active
06509422
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a resin composition comprising a fluorinated polymer having a high fluorine content and a polymer containing no fluorine, which are uniformly and finely dispersed and mixed by a dispersing agent.
BACKGROUND ART
Heretofore, fluorinated polymers represented by a tetrafluoroethylene polymer, are excellent in heat resistance, flame retardant properties, chemical resistance, weather resistance, anti-sticking properties, low frictional properties and low dielectric properties, and used in a wide range of fields including, for example, a coating material for heat-resistant flame-retardant electrical wires, a corrosion-resistant piping material for chemical plants, a material for agricultural vinyl film houses, and a mold release coating material for kitchen equipment.
Such properties are derived from the three points of a strong C-F bond, a small polarizability and a weak intermolecular cohesion energy. Particularly, a low intermolecular cohesion energy makes the surface energy of the polymer low, whereby the affinity with another material, particularly with a polymer containing no fluorine, is low. Accordingly, a composition comprising a fluorinated polymer and a polymer containing no fluorine, one of which is uniformly and finely dispersed in the other polymer, can not be obtained.
To overcome this problem, the present inventors have proposed a composition comprising a fluorinated polymer, a non-fluorinated polymer, and as a dispersing agent, a grafted polymer obtained by reacting a fluorinated polymer having hydrogen atoms bonded to carbon atoms in its main chain, with a vinyl monomer having a functional group, while generating radicals, before (JP-A-9-118802).
This dispersing agent is effective for a fluorinated polymer having a low fluorine content, such as one having hydrogen atoms bonded to carbon atoms in its main chain in a certain proportion. However, there is a limitation for uniformly and finely dispersing a non-fluorinated polymer with a polymer having a high fluorine content, or with a polymer containing substantially no hydrogen atom bonded to carbon atoms in its main chain.
DISCLOSURE OF THE INVENTION
The present invention has been made to overcome the above-mentioned problems. The present inventors have found that a fluorine-containing resin composition comprising a polymer having a high fluorine content and a non-fluorinated polymer containing no fluorine, which are uniformly and finely dispersed and mixed, can be obtained, by using a fluorinated compound having, as a functional group, a carboxylic acid group or its derivative, or a sulfonic acid group or its derivative, in its molecule, as a dispersing agent to disperse and mix the polymers, and the present invention has been accomplished.
Namely, the present invention provides a fluorine-containing resin composition which comprises, in 100 parts by weight of the composition, from 2 to 89 parts by weight of a fluorinated polymer (a) which has a fluorine content of at least 65 wt % in its polymer molecule (hereinafter referred to as fluorinated polymer (a)), from 97 to 10 parts by weight of a polymer (b) containing no fluorine (hereinafter referred to as non-fluorinated polymer (b)), and from 1 to 35 parts by weight of a functional group-containing fluorinated compound (c) having, as a functional group, a carboxylic acid group or its derivative, or a sulfonic acid group or its derivative, in its molecule.
Here, the fluorinated polymer (a) has neither carboxylic acid group or its derivative, nor sulfonic acid group or its derivative, in its molecule, and it is different from the functional group-containing fluorinated compound (c).
The composition of the present invention has an island structure in which depending upon the amounts of the fluorinated polymer (a) and the non-fluorinated polymer (b) to be blended, the component with a smaller blending amount is dispersed in the other component. Accordingly, in the present invention, the component to be dispersed uniformly and finely, is not limited, and the structure of the composition may be such that the fluorinated polymer (a) is dispersed in the non-fluorinated polymer (b), or the structure may be such that the non-fluorinated polymer (b) is dispersed in the fluorinated polymer (a).
BEST MODE FOR CARRYING OUT THE INVENTION
As the fluorinated polymer (a) to be used in the present invention, a fluorinated polymer having a fluorine content of at least 65 wt % in its polymer molecule is used. Further, in view of heat resistance of the polymer, a polymer having a fluorine content of at least 70 wt % is preferably used.
As a preferred fluorinated polymer (a), a homopolymer of a fluoroolefin selected from tetrafluoroethylene (hereinafter referred to as TFE) and chlorotrifluoroethylene (hereinafter referred to as CTFE), or a copolymer of a fluoroolefin with a fluorinated monomer such as perfluoro(alkyl vinyl ether), hexafluoropropylene (hereinafter referred to as HFP), vinylidene fluoride or vinyl fluoride, may be used. Further, a copolymer of the above-mentioned fluoroolefin with an &agr;-olefin containing no fluorine such as ethylene, propylene or butene, may be used, so long as the fluorine content in its polymer is at least 65 wt %.
As a specific example of such a fluorinated polymer, a TFE polymer (hereinafter referred to as PTFE), a CTFE polymer (hereinafter referred to as PCTFE), a TFE-HFP copolymer (hereinafter referred to as FEP), a TFE-perfluoro (alkyl vinyl ether) copolymer (hereinafter referred to as PFA), a TFE-ethylene copolymer (hereinafter referred to as ETFE), a CTFE-ethylene copolymer or a TFE-propylene copolymer may, for example, be mentioned. Preferred is PTFE, PCTFE, FEP or PFA, and particularly preferred is PFA, in view of heat resistance and chemical stability.
The non-fluorinated polymer (b) to be used in the present invention is a polymer containing no fluorine atom in its molecule.
The non-fluorinated polymer (b) is preferably a heat-resistant polymer capable of being melted and mixed with a fluorinated polymer having a high heat resistance. It is particularly preferably a polymer having a glass transition point (Tg) of at least 140° C. as an index of the heat resistance. As a specific example of the non-fluorinated polymer (b), an engineering plastic such as a polyamide (hereinafter referred to as PA), a polyamidoimide (hereinafter referred to as PAI), a polyetherimide (hereinafter referred to as PEI), a thermoplastic polyimide, a polycarbonate (hereinafter referred to as PC), a polysulfone (hereinafter referred to as PSF), a polyether sulfone (hereinafter referred to as PES), a polyether ether ketone (hereinafter referred to as PEEK), a polyallylate (hereinafter referred to as PAR), a modified PPO, a reinforced PET or a liquid crystal polymer (hereinafter referred to as LCP) may, for example, be mentioned. Among these, particularly preferred is PEI, PAI, a polybismaleimide, a thermoplastic polyimide or PES, and most preferred is PEI.
The contents of these fluorinated polymer (a) and non-fluorinated polymer (b) is such that in 100 parts by weight of the composition, the fluorinated polymer (a) is from 2 to 89 parts by weight, preferably from 10 to 44 parts by weight, and the non-fluorinated polymer (b) is from 97 to 10 parts by weight, preferably from 89 to 55 parts by weight.
In the present invention, as a dispersing agent, a functional group-containing fluorinated compound (c) having, as a functional group, a carboxylic acid group or its derivative, or a sulfonic acid group or its derivative, in its molecule (hereinafter referred to as dispersing agent (c)) is used. By using the dispersing agent (c), a composition having a structure in which the above-mentioned (a) and (b) are uniformly and finely dispersed, can be obtained. The composition of the present invention can not be obtained by simply blending (a) and (b). Such a dispersing agent can commonly be available as a surface active agent. Further, in view of the affinity with the fluorinated polymer (a), a compound containing fluorine is prefe
Eriguchi Takeshi
Kaida Yuriko
Kamiya Hiroki
Nagashima Masako
Umino Masao
Acquah Samuel A.
Asahi Glass Company Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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