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
2000-04-19
2002-03-19
Sellers, Robert E. L. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S029000, C525S101000, C525S280000, C525S294000, C525S297000, C525S299000, C525S318000, C525S319000, C525S323000, C525S324000, C525S426000, C525S446000
Reexamination Certificate
active
06359081
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a block copolymer type compatibilizing agent for a blend resin containing a vinyl-based polymer and a condensation type polymer, and a method for production thereof.
The present invention relates to a functional block copolymer for imparting functions such as a ultraviolet ray absorbing ability and flame retardant property to a synthetic resin and a method for production thereof.
PRIOR ART
In general, a synthetic resin is required to have various functions depending on the use and the using condition, and therefore, a conventional synthetic resin is modified to impart novel functions to the resin by adding functional monomers or polymers into the resin. As an example, for prevention of ultraviolet interference on a synthetic resin, a ultraviolet absorber such as a benzophenone derivative, benzotriazol derivative or the like is added to prevent ultraviolet ray-induced degradation of the synthetic resin itself and to impart weatherability to the resin.
For imparting flame retardant property, antimony oxide, phosphorus compounds or halogenated compounds is also conventionally used.
In addition to the addition of such functional monomers or polymers, there is a blend resin method as a method widely used for improvement of the properties of a synthetic resin. The blend resin method is a method of mixing two or more polymers to form a synthetic resin so as to take in excellent properties of each polymer for improvement of the characteristics of the resin. For forming the blended resin, it is important that these polymers have compatibility to each other since the forming is in general conducted after mixing and melting them. When the compatibility between the polymers is poor, the blended resin sometimes can not manifest the expected characteristics thereof and some modifiers for compatibility or compatibilizers should be added to the polymers.
Though it can also be supposed that a condensation-type polymer (for example, ester-based polymer) and a vinyl-based polymer are combined and blended, when these polymers are incompatible or partially compatible, suitable compatibilizers are required.
Regarding associated techniques, there is known a technique for copolymerization of a condensation-type polymer (for example, polyester-based polymer) and vinyl-based polymer (Japanese Patent Application Laid-Open (JP-A) No. 59(1984)-27908), and since this block copolymer itself was used as a thermoplastic resin being subjected to heat forming, the characteristics thereof were determined by the composition and properties from each polymer, and, further, it was difficult to regulate the composition at will and the copolymer resin was expensive due to the production method.
Further, there is a case in which whole resin may have the function through the resin and a case in which only the surface layer of the formed resin article may have the special function. Regarding the former case, compatibility is required for mutual solution of blended polymers or for micronization and dispersion of the polymers in the micro structure of the resin, and for this reason a compatibilizing agent is utilized in the melt-blend of incompatibilizing polymers.
As an example of the latter case, there is a surface antistatic agent which lowers the surface electrical resistance and impart electrical conductivity. Regarding this technique, Japanese Patent Application Publication (JP-B) No. 5(1993)-41668 suggests an antistatic agent comprising a block copolymer obtained by introducing a hydrophilic vinyl-based segment and a hydrophobic vinyl-based segment using a polyazo compound as a polymerization initiator, in which electrical static charge of the resin is prevented by producing surface electrical conductivity by the hydrophilic segment.
Further, in relation to the present invention, Japanese Patent Application Publication (JP-B) No. 5(1993)-41668 suggests an antistatic agent for imparting electrical conductivity to a vinyl-based synthetic resin obtained by using an azo group as a vinyl polymerization initiator and by block-polymerizing vinylmonomers in turn, to form a hydrophilic segment and hydrophobic segment in a polyazo compound.
Also, there is known a technique in which a polycarbonate copolymer which is obtained by copolymerization with a styrene-based polymer and subsequent modification is used as an optical lens, and the optical distortion thereof is improved (Japanese Patent Application Laid-Open (JP-A) No. 61(1986)-19630).
Regarding the above-mentioned ultraviolet absorbing property, the above-mentioned lower-molecular ultraviolet absorbing agent is conventionally added in a small amount (for example, from 0.02 to 0.1% (by weight)). However, even if this agent is added in a large amount in the process of forming of a synthetic resin, it is vaporized in the step of heat-melting, therefore, the yield thereof is low and the synthetic resin is unpreferably expensive.
Also, as a higher-molecular ultraviolet absorbing agent, random copolymers formed of styrene and a vinyl-based ultraviolet absorbing compound are known. Though the higher-molecular ultraviolet absorbing agent is effective for prevention of the vaporization in heat-melting, its compatibility with a resin to be added becomes a problem. For example, regarding the above-mentioned ultraviolet-absorbing polymer comprising styrene, because the polymer has poor compatibility with a polycarbonate, the homogeneous dispersion of the polymer can not be obtained, so that synthetic resins in which the polymer can be utilized are limited.
Also regarding flame retardant property, a phosphorus compound is utilized from the viewpoint of stability and transparency for a transparent synthetic resin. However, in this case, such compatibility that enables uniform dispersion in the resin is necessary.
In general, as functions to be manifested uniformly in the resin, there are flame retardant property, impact resistance, radiation resistance and the like. For manifesting these functions, it is necessary that functional components manifest compatibility to the synthetic resin after melting and are dispersed uniformly in the resin.
Further, in the point of functionalization of the surface properties and conditions of a synthetic resin, there are required ultraviolet absorbing property, pollution resistance, antibacterial property and the like in addition to antistatic property and electrical conductivity. In this case, uniform dispersion within the resin is not necessarily required, rather, it is required a nature that these function imparting components gather on the surface in a cooling process after melting in forming. Therefore, because of these functions, necessity occurs to regulate distribution of the functional components in the resin.
On the other hand, also regarding polymer components in the synthetic resin, there is a case in which not only a vinyl-based polymer but also a condensation-type polymer, particularly an aromatic ester-based polymer is required to have these functions, and further there is a case in which a specific resin is required to comprise a material endowed with these specific functions. Therefore, when a function modifying agent is used, compatibility and uniform dispersion property between the specific resin and the modifying agent become problems.
Further, as described-above, when a mixture of a polycarbonate and a styrene-based polymer is used as a optical lens, the birefringence thereof is a problem. For this use, there is used a resin having negative optical anisotropy opposite to that of a polycarbonate, for example a resin having lowered optical aeolotropy by copolymerization with a polystyrene as described above. However, if a polycarbonate and a polystyrene are not copolymerized but can be mixed in a constant ratio and the structure thereof can be micronized differing from the above-mentioned method, it is expected that optical isotropy can be provided and birefringence can be solved by such a simple means as mixing, and, a compatibilizing agent will be required here.
Further, since poly
Agari Yasuyuki
Makimura Yoichiro
Shimada Masayuki
Sellers Robert E. L.
Takiron Co., Ltd.
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