Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1998-02-27
2000-04-04
Sellers, Robert E.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
525423, 525481, 525485, 525486, 525488, 525510, 525524, 525526, 525528, 525533, 525934, C08G 5906, C08G 5914, C08L 6302
Patent
active
060462841
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to a modified resin composition containing phenolic hydroxyl group and a curable resin composition thereof. The invention further relates to the epoxy resin composition which is obtained by epoxidation of said modified resin composition containing phenolic hydroxyl group by epihalohydrin and a curable resin composition of said epoxy resin.
BACK GROUND OF THE INVENTION
In general, an epoxy resin composition is broadly applied as a component of paint or adhesive and for various uses such as electric fields or civil engineering because of the excellent chemical and physical properties which an epoxy resin composition originally has. However, the required level for the features of epoxy resin composition are becoming higher and higher along with the progress of each field of application. Especially, in the uses of powder coating, molding materials or paints for inside surface coating of a can, the development of a resin whose contents of lower molecular weight components is low is expected. For instance, since an epoxy resin powder coating has a good durability for corrosion and has a strong resistance to chemicals, it is practically used as the paint for an inner and an outer surface coating of a steel tube or as the paint for a steel frame coating.
Generally, as an epoxy resin composition, bisphenol A type solid epoxy resin is used and as a hardener, dicyandiamide, acid anhydride, aromatic amine, dihydrazide or phenol resin is used. As a phenol resin which is used as the hardener, a novolac type phenol resin, preferably the modified resin which has a phenolic hydroxyl group at both ends can be used. For instance, the composition obtained by a chemical reaction between a bisphenol type epoxy resin composition obtained by reacting bisphenol such as bisphenol A or bisphenol F with epichlorohydrin under the presence of hydroxide of alkali metal and excess bisphenol. As the modified resin which contains phenolic hydroxyl group, "TH-4100" produced by TOHTO KASEI, "EPICURE 171 and 172" produced by YUKA SHELL EPOXY and "XD-8062" of DOW CHMICAL are currently in the market. The powder coating which uses above mentioned modified resin as a hardener is disclosed, for instance, in Japanese Patent Laid-open publication 54-7473, Japanese Patent Laid-open publication 58-79011, Japanese Patent Laid-open publication 58-113267 and Japanese Patent Laid-open publication 61-12762, and these powder coating are remarkably improved so as to be applied to outer surface of a pipe. However, in these conventional modified resins which contains phenolic hydroxyl group, since from 5 to 20 wt % of bisphenol A used for the reacted remains, and vaporizes at a baking procedure, following two phenomena are pointed out as serious problems. That is, accompanied with the vaporization of bisphenol A, many tiny pin holes are formed on the surface of coated film and the physical properties of coated film is deteriorated, further the inside of a furnace for baking is polluted. Further, there is another problem that, by the vaporization of bisphenol A, the anticipated mixing ratio with epoxy resin is changed and deteriorates the physical properties of a coated film.
In the fields of powder coating and molding materials, conventional bisphenol type solid epoxy resins have a problem of blocking and deteriorate the stability of quality for storing, when a low epoxy equivalent resin is used. To solve the above mentioned problems, an epoxy resin not containing a low molecular component which causes a blocking problem, whose viscosity at molten state is low and has good fluidity has been expected.
As a method to remove low molecular weight component in solid type epoxy resin, for instance, the method to remove low molecular weight component by a molecular distillation is well known. However, even by this method, it is difficult to remove the low molecular weight component whose degree of polymerization (hereafter shortened to n) is bigger than 0, further the problem that the solid epoxy resin is thermally de
REFERENCES:
patent: 4186036 (1980-01-01), Elms et al.
patent: 5405931 (1995-04-01), Kohno et al.
patent: 5407978 (1995-04-01), Bymark et al.
Hanafusa Masayoshi
Nozawa Hidenori
Saitoh Nobuhisa
Shinohara Shuya
Takeda Yasuyuki
Sellers Robert E.
Tohto Kasei Co Ltd
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