Patent Number: 
Section: description

A better understanding of the present invention may be obtained in light of the following examples which are set forth to illustrate, but are not to be construed to limit the present invention. A wetting agent, a coalescing agent, a freeze/thaw stabilizer, a defoamer, and a thickner were sufficiently mixed in deionized water as indicated in Table 1, below. The mixture was added with polyaniline and stirred at 1,000-2,000 rpm for about 30 minutes to give a homogeneous phase. Thoroughly mixing the homogeneous phase with a vinyl emulsion gave a coating material. To be tested for physical properties requisite for an electromagnetic wave-shielding coating, the coating material was coated on a slate plate and naturally dried to give a coating 40 xcexcm thick. The coating was measured for adhesive strength in accordance with xe2x80x9cpaint adhesiveness test of ISO 2409xe2x80x9d, hardness in accordance with xe2x80x9cpencil hardness of JIS K-5400xe2x80x9d, and electromagnetic wave-shielding efficiency in accordance with xe2x80x9cASTM-D4935-89xe2x80x9d. The results are given in Table 3, below. A coating material was prepared in a similar manner to that of Example 1, except that an acrylic emulsion was used, instead of a vinyl emulsion. The physical properties were assayed in the same manner as in Example 1 and the results are given in Table 3, below. A hydroxy group-containing acrylic resin, a dispersant, a defoamer, a leveling agent, a UV stabilizer, a UV absorber, and a catalyst were sufficiently mixed as indicated in Table 2, added with 10% by weight of polyaniline, and stirred for 30 minutes at 1,000-2,000 rpm to give a homogeneous phase. Just before use, this homogeneous phase was polyisocyanate resin and a mixed solvent to give a coating material. To be tested for physical properties requisite for an electromagnetic wave-shielding coating, the coating material was painted over a plastic plate by spraying and naturally dried to give a coating 50 xcexcm thick. The coating was measured for adhesive strength in accordance with xe2x80x9cpaint adhesiveness test of ISO 2409xe2x80x9d, hardness in accordance with xe2x80x9cpencil hardness of JIS K-5400xe2x80x9d, and electromagnetic wave-shielding efficiency in accordance with xe2x80x9cASTM-D4935-89xe2x80x9d. The results are given in Table 3, below. A coating material was prepared in a similar manner to that of Example 3, except that the hydroxy group-containing acrylic emulsion was used at an amount less by 10% by weight than as in Example 3 while polyaniline was used at 20% by weight. The physical properties were assayed in the same manner as in Example 3 and the results are given in Table 3, below. A coating material was prepared in a similar manner to that of Example 1, except that polyaniline was not used and the vinyl emulsion was further added as much. The physical properties were assayed in the same manner as in Example 1 and the results are given in Table 3, below. A coating material was prepared in a similar manner to that of Example 2, except that polyaniline was not used and the acryl emulsion was further added as much. The physical properties were assayed in the same manner as in Example 2 and the results are given in Table 3, below. A coating material was prepared in a similar manner to that of Example 3, except that polyaniline was not used and the acryl resin was further added as much. The physical properties were assayed in the same manner as in Example 3 and the results are given in Table 3, below. In Table 1, Igepal CO-610 (Rhodia Co.) is a brand name of polyoxyethylene nonlyphenyl ether (ethylene oxide: 7.7 mol), Texanol (Eastman Co.) a brand name of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, Nopalcol 1-TW (Henkel Co.) a brand name of PEG-2 tallowate, and Natrosol plus (Hercules Co.) a brand name of a modified hydroxyethylcellulose polymer. In Table 2, BYK 320 (BYK-Chemie Co.) is a brand name of a polyester modified methylalkylpolysiloxane copolymer, BYK 065 (BYK-Chemie Co.) a brand name of methylalkylsiloxane, BYK 355 (BYK-Chemie Co.) a brand name of polyacrylate, Tinuvin 328 (Ciba-Geigy Co.) a brand name of 2-2xe2x80x2-hydroxy-3,5xe2x80x2-di-t-amylphenylbenzotriazole, Tinuvin 292 (Ciba-Geigy Co.) a brand name of a benzophenone derivative, Fascat 4231 (Elf Atochem Co) a brand name of an organic tin compound, and Desmodur N-3600 (Bayer Co.) a brand name of hexamethylene diisocyanate isocyanurate (NCO=23%). Taken together, the data obtained in above examples demonstrate that the electromagnetic wave-shielding coating materials according to the present invention superior in physical properties requisite for coating materials, such as adhesive strength and pencil hardness. Thus, the electromagnetic wave-shielding coating materials of the present invention can be easily applied to plastics as well as iron matrices and firmly adhere thereto without producing paint dust. Also, the electromagnetic wave-shielding coating materials can be well coated even on edge portions of cases of various electromagnetic appliances. In addition, the electromagnetic wave-shielding coating materials of the present invention show excellent EMI shielding effects. Thus, when applied to surfaces various electromagnetic appliances, the coating materials can shield electric and magnetic fields of the electromagnetic waves generated from the electromagnetic appliances, thereby protecting the body therefrom. For example, the electromagnetic wave-shielding coating materials of the present invention can be used as paints for automobiles with the aim of preventing the electromagnetic wave interference, which is believed to cause burst-to-start. Also, the electromagnetic wave-shielding coating materials are effective in shielding electromagnetic waves from cellular phones, pagers, television monitors, computer monitors, etc. Further, the electromagnetic wave-shielding coating materials of the present invention are so antistatic that the objects applied by the coating materials are not allowed to be charged. As described hereinbefore, the electromagnetic wave-shielding coating materials, which are prepared by mixing a polymer, self-resistant to electromagnetic waves, with a paint matrix at suitable amounts, are effective in shielding electromagnetic waves radiating from various electromagnetic appliances in addition to being superior in coatability. The electromagnetic wave-shield coating materials are expected to prevent the burst-to-start phenomenon of automobiles, which is supposed to be attributed to electromagnetic wave interference. In addition, the electromagnetic wave-shielding coating materials of the present invention have an antistatic effect such that an object, when coated with the coating materials, cannot be charged on its surfaces. The present invention has been described in an illustrative manner, and it is to be understood that the terminology used is intended to be in the nature of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, it is to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.