Patent Number: 054223830
Section: description

The following examples will further illustrate the present invention. Parts are by weight. In the present specification, the term "average particle diameter" is intended to refer to a Stokes diameter when the particles have a diameter of less than 1 .mu.m and to an equivalent volume diameter when the particles have a diameter of 1 .mu.m or more. EXAMPLE 1 Preparation of Composition Particles by Dry-Mixing Method (Method A) Each of the four colorants shown below was charged into a high speed jet impact-type mixer (Hybridizer NHS-1 manufactured by Nara Machinery Inc.) together with cordierite (SS-200 manufactured by Marusu Yuyaku Inc., average particle diameter: 10 .mu.m, white LB absorber) and the contents were mixed for 5 minutes at a revolution speed of 8,000 rpm to obtain composite particles having an average particle diameter of 10 .mu.m and a weight ratio of the colorant to the cordierite of 1:9. Colorant 1. Titanium dioxide (TiO.sub.2), Tipaque R-830 manufactured by Ishihara Sangyo Inc., white pigment, average particle diameter: 0.255 .mu.m, hereinafter referred to as Ti-W; PA1 2. Titanium yellow (mixture of TiO.sub.2, NiO.sub.2 and Sb.sub.2 O.sub.3, Tipaque TY-70 manufactured by Ishihara Sangyo Inc., yellow pigment, average particle diameter: 1.05 .mu.m, hereinafter referred to as Ti-Y; PA1 3. FeOOH, Mapicotan YP-100N manufactured by Tone Sangyo Inc., orange yellow pigment, average particle diameter: 0.2-1.0 .mu.m, hereinafter referred to as Fe-O; PA1 4. cupric oxalate, light blue, average particle diameter: 1.0 .mu.m, hereinafter referred to as Cu-B. PA1 A: very clear PA1 B: clear PA1 C: slightly unclear PA1 D: unclear PA1 1. Polyethylene (hereinafter referred to as Resin-PE) PA1 2. Polycarbonate (hereinafter referred to as Resin-PC) PA1 3. Polystyrene (hereinafter referred to as Resin-PS) PA1 5. Niobium (V) oxide, white colorant, average particle diameter: 1.68 .mu.m, hereinafter referred to as Nb-W PA1 1. Cordierite (the same as used in Example 1) PA1 2. Zeolite: Zeolite 4A manufactured by Union Showa Inc. average particle diameter: 10 .mu.m, white particles PA1 3. Zirconium silicate: Micropax manufactured by Hakusui Chemical Industries Inc., average particle diameter: 2.0 .mu.m, white particles, hereinafter referred to as Zr-silicate PA1 4. Calcium silicate: Niat 400 manufactured by Interpace Inc., average particle diameter: 6.0 .mu.m, white particles, hereinafter referred to as Ca-silicate PA1 EPIKOTE 828: Bisphenol A epoxy resin manufactured by Yuka-Shell Epoxy Inc. PA1 EPIKOTE 1002: Bisphenol A epoxy resin manufactured by Yuka-Shell Epoxy Inc. PA1 Anhydride A: Methyltetrahydrophthalic anhydride PA1 Anhydride B: Benzophenone tetracarbolylic anhydride PA1 Phenol Resin: Phenol novolak resin (Tamanol 754, hydroxyl equivalent: 104, manufactured by Arakawa Chemical Industry Inc.) PA1 TPP: Triphenylphosphine PA1 Silica: Amorphous silica Micron S-COL (manufactured by Micron Inc., average particle size: 28 .mu.m) PA1 Fe-O: Colorant (Example 1) PA1 Cordierite: LB absorber (Example 1) PA1 CoA-Fe-O: Composite particles obtained in Example 2 PA1 CoD-Fe-O: Composite particles obtained by the wet-mixing method (Method D shown in Example 6 using Fe-O (1 part) as a colorant and cordierite (9 parts) as an LB absorber, average particle diameter: 12 .mu.m) Each of the thus obtained four kinds of composite particles (hereinafter referred to as CoA-Ti-W, CoA-Ti-Y, CoA-Fe-O and CoA-Cu-B) were press-molded into a tablet having a diameter of 16 mm and a thickness of 1.0 mm and the tablet was irradiated with a laser beam (CO.sub.2 laser, energy 4J/cm.sup.2) using a laser beam marking device (TEA Unimark 400-4J manufactured by Ushio Electric Co., Ltd.) to obtain bar mark (line width: 2 mm). Irradiation was performed only once or repeated five times. The thus obtained marks were observed with native eyes to evaluate the visibility thereof on the basis of the following ratings: The results are summarized in Table 1. TABLE 1 ______________________________________ Visibility Colorant Once Five times Color of Mark ______________________________________ Ti-W C A black Ti-Y C A black Fe-O B A black Cu-B C A black ______________________________________ Comparative Example 1 Example 1 was repeated in the same manner as described except that no cordierite was used. The results are shown in Table 2. TABLE 2 ______________________________________ Visibility Colorant Once Five times ______________________________________ Ti-W C C Ti-Y C C Fe-O C B-C Cu-B C C ______________________________________ EXAMPLE 2 Preparation of Laser Beam Absorbing Plate A thermoplastic resin shown below was blended with a quantity of respective one of the composite particles obtained in Example 1. The blend was mixed at a temperature sufficient to melt the resin and then molded into a plate having a width of 20 mm, a length of 50 mm and a thickness of 1 mm. Laser marking test was carried out in the same manner as described in Example 1. The results are summarized in Table 3. The color of the marks was black. Thermoplastic Resin: TABLE 3 ______________________________________ Composite Particles Visibility Resin Kind Amount (parts*) Once Five times ______________________________________ Resin-PE CoA-Ti-W 10 C B Resin-PE CoA-Ti-Y 10 C B Resin-PE CoA-Fe-O 2 B A Resin-PE CoA-Cu-B 10 C B Resin-PC CoA-Ti-W 10 C B Resin-PC CoA-Ti-Y 10 C B Resin-PC CoA-Fe-O 2 B A Resin-PS CoA-Ti-W 10 C B Resin-PS CoA-Ti-Y 10 C B Resin-PS CoA-Fe-O 2 B A ______________________________________ EXAMPLE 3 Preparation of composite Particles by Singering Method (Method B) A colorant (4 g) shown in Table 4 and cordierite (36 g, the same as used in Example 1) were charged in a planetary ball mill (P-5 manufactured by Flitch Japan Inc.) together with 50 g of water and the contents were mixed for 1 hour. The resulting dispersion was filtered and the solids phase was dried and sintered at 1,300.degree. C. for 1 hour. The sintered mass was then pulverized into particles having an average particle diameter of 15 .mu.m. Preparation of Laser Beam Absorbing Plate The thus obtained composite particles (CoB-Ti-W, CoB-Ti-Y and CoB-Nb-W, 10 parts) were each mixed with a resin (100 parts) shown in Table 4 and the resulting composition was molded into a plate in the same manner as that in Example 2. The plate was then irradiated with a laser beam marking in the same manner as that in Example 1 to give black marks whose visibility was shown in Table 4. For the purpose of comparison, the resin (100 parts), the colorant (1 part) and cordierite (9 parts) were simultaneously mixed and the resulting composition was formed into a plate in the same manner as that in Example 2. The laser marking on the comparative samples was white to gray and had visibility shown in Table 4. Colorant TABLE 4 ______________________________________ Experiment 1* 2 3* 4 5* 6 7 ______________________________________ Resin Resin-PC 100 100 100 100 100 100 Resin-PE 100 Colorant Ti-W 1 Ti-Y 1 Nb-W 1 Cordierite 9 9 9 Composite CoB-Ti-W 10 10 CoB-Ti-Y 10 CoB-Nb-W 10 Visibility Once D B D B D C B Five times D A D A D B A ______________________________________ *Comparative samples EXAMPLE 4 Preparation of Composite Particles by Dry-Mixing Method (Method A) Using the combination of a colorant and an LB absorber shown below, the following five composite particles (CoA-Ti-W, ZeA-Ti-W, ZrA-Ti-W, CaA-Ti-W and CoA-Nb-W) were prepared by the Method A shown in Example 1. CoA-Ti-W: Ti-W and cordierite ZeA-Ti-W: Ti-W and zeolite ZrA-Ti-W: Ti-W and zirconium silicate CaA-Ti-W: Ti-W and calcium silicate CoA-Nb-W: Nb-W and cordierite LB absorber: Preparation of Laser Beam Absorbing Plate The thus obtained composite particles were each mixed with a resin (100 parts) shown in Table 5 and the resulting composition was molded into a plate in the same manner as that in Example 2. The plate was then irradiated with a laser beam marking in the same manner as that in Example 1 to give grayish black or black marks whose visibility was shown in Table 5. For the purpose of comparison, the resin (100 parts), the colorant (1 part) and the LB absorber (9 parts) shown in Table 5 were simultaneously mixed and the resulting composition was formed into a plate in the same manner as that in Example 2. The laser marking on the comparative samples was white to gray and had visibility shown in Table 5. TABLE 5 ______________________________________ Experiment 1* 2 3* 4 5* 6 ______________________________________ Resin Resin-PC 100 100 100 100 100 100 Resin-PE Colorant Ti-W 1 1 1 Nb-W LB absorber Cordierite 9 Zeolite 9 Zr-silicate 9 Ca-Silicate Composite CoA-Ti-W 10 ZeA-Ti-W 10 ZrA-Ti-W 10 CaA-Ti-W CoA-Nb-W Visibility Once D C D C D C Five times D B D B D B ______________________________________ Experiment 7* 8 9* 10 11* ______________________________________ Resin Resin-PC 100 100 100 100 Resin-PE 100 Colorant Ti-W 1 Nb-W 1 LB absorber Cordierite 9 Zeolite Zr-silicate Ca-Silicate 9 Composite CoA-Ti-W 10 ZeA-Ti-W ZrA-Ti-W CaA-Ti-W 10 CoA-Nb-W 10 Visibility Once D C D C C Five times D B D B B ______________________________________ *Comparative samples EXAMPLE 5 Preparation of Composite Particles by Sintering Method (Method B) Using the combination of a colorant and an LB absorber shown below, the following five composite particles (CoB-Ti-W, ZeB-Ti-W, ZrB-Ti-W, CaB-Ti-W and CoB-Nb-W) were prepared by the Method B shown in Example 3. CoB-Ti-W: Ti-W and cordierite ZeB-Ti-W: Ti-W and zeolite ZrB-Ti-W: Ti-W and Zr silicate CaB-Ti-W: Ti-W and Ca silicate CoB-Nb-W: Nb-W and cordierite Preparation of Laser Beam Absorbing Plate The thus obtained composite particles were each mixed with a resin (100 parts) shown in Table 6 and the resulting composition was molded into a plate in the same manner as that in Example 2. The plate was then irradiated with a laser beam marking in the same manner as that in Example 1 to give black marks whose visibility was shown in Table 6. For the purpose of comparison, the resin (100 parts), the colorant (1 part) and the LB absorber (9 parts) shown in Table 6 were simultaneously mixed and the resulting composition was formed into a plate in the same manner as that in Example 2. The laser marking on the comparative samples was white to gray and had visibility shown in Table 6. TABLE 6 ______________________________________ Experiment 1* 2 3* 4 5* 6 ______________________________________ Resin Resin-PC 100 100 100 100 100 100 Resin-PE Colorant Ti-W 1 1 1 Nb-W LB absorber Cordierite 9 Zeolite 9 Zr-silicate 9 Ca-Silicate Composite CoB-Ti-W 10 ZeB-Ti-W 10 ZrB-Ti-W 10 CaB-Ti-W CoB-Nb-W Visibility Once D B D C D B Five times D A D B D A ______________________________________ Experiment 7* 8 9* 10 11 ______________________________________ Resin Resin-PC 100 100 100 100 Resin-PE 100 Colorant Ti-W 1 Nb-W 1 LB absorber Cordierite 9 Zeolite Zr-silicate Ca-Silicate 9 Composite CoB-Ti-W 10 ZeB-Ti-W ZrB-Ti-W CaB-Ti-W 10 CoB-Nb-W 10 Visibility Once D C D C B Five times D B D B A ______________________________________ *Comparative samples EXAMPLE 6 Preparation of composite Particles by Precipitation Method (Method C) Into a three-necked flask were charged 10 g of cordierite (the same as used in Example 1) and 100 ml of water and the mixture was heated to 100.degree. C. With stirring, a solution of titanium sulfate (16.68 g) dissolved in 25.02 ml of water was poured dropwise into the flask. The resulting mixture was refluxed for 6 hours with stirring. The resulting precipitates were filtered and washed with water until the pH of the washed water became 6-7. The scanning electric microscope analysis revealed that the cordierite particles were each covered with titanium oxide. The precipitates thus obtained were then calcined at 800.degree. C. to obtain composite particles CoC-Ti-W having an average particle diameter of 15 .mu.m and a weight ratio of Ti-W to cordierite of 3:7. Preparation of composite Particles by Wet-Mixing Method Using Binder (Method D) Into a planetary ball mill were charged 8 g of polyethylene glycol (weight average molecular weight: 6000), 10 g of water and 10 g of Ti-W (titanium dioxide). The contents were mixed and thereafter added with 300 g of water. Further mixing of the contents gave a first suspension. Polyethylene glycol (the same as above, 3 g) was dissolved in 1,500 ml of water, into which 190 g of cordierite (the same as used in Example 1) were mixed with stirring to obtain a second suspension. With stirring, the first suspension was added to the second suspension. The resulting mixture was filtered and the separated solids were dried to obtain composite particles CoD-Ti-W having an average particle diameter of 10 .mu.m and a weight ratio of Ti-W to cordierite of 1:19. The scanning electric microscopic analysis revealed that titanium dioxide deposits on the surfaces of cordierite particles. The thus obtained composite particles CoC-Ti-W and CoD-Ti-W as well as CoA-Ti-W (Example 1) and CoB-Ti-W (Example 3) were each formed into a disc in the same manner as that in Example 1. Laser marking was carried out in the same manner as that in Example 1 to give the results shown in Table 7. TABLE 7 ______________________________________ Visibility Composite Once Five times Color of Mark ______________________________________ CoA-Ti-W C A black CoB-Ti-W B A black CoC-Ti-W B A black CoD-Ti-W C A gray-black ______________________________________ EXAMPLE 7 Using the colorants and the LB absorbers shown in Table 8, various composite particles were prepared by the same dry-mixing method (Method A) shown in Example 1. Each composite was formed into a disc in the same manner as that in Example 1. Laser marking was carried out in the same manner as that in Example 1 to give the results shown in Table 8. TABLE 8 ______________________________________ Compo- LB Visibility Color of site No. Absorber Colorant Once Five times Mark ______________________________________ 1 cordierite Ti-W C A black 2 cordierite Ti-Y C A black 3 cordierite Fe-O B A black 4 cordierite Cu-B C A black 5 Zr-silicate Ti-W C B black 6 Zr-silicate Ti-Y C B black 7 Zr-silicate Fe-O B A black 8 Zr-silicate Cu-B C A black 9 zeolite Ti-W C B black 10 zeolite Ti-Y C B black 11 zeolite Fe-O B A black 12 zeolite Cu-B C B black 13 Ca-silicate Ti-W C B black 14 Ca-silicate Ti-Y C B black 15 Ca-silicate Fe-O B A black 16 Ca-silicate Cu-B C B black ______________________________________ EXAMPLE 8 The ingredients shown in Table 9 below were blended in the amounts shown in Table 9 to obtain compositions of Sample Nos. 1-8. In Table 9, the amounts are parts by weight and abbreviations and trademarks are as follows: Each of Samples Nos. 1-8 was applied on a surface of an aluminum plate (50 mm.times.50 mm.times.1.5 mm) and the coating was heated at 120.degree. C. to form a cured resin layer (thickness: 0.5 mm) thereon. Bar mark (line width: 0.2 mm) was then marked on the coated resin layer by irradiation with a laser beam (CO.sub.2 laser, wavelength: 10.6 .mu.m, energy: 4 J/cm.sup.2) using a commercially available laser beam marking device (TEA Unimark 400-4J, manufactured by Ushio Electric Co., Ltd.). The color of the mark and the visibility were as summarized in Table 9. TABLE 9 __________________________________________________________________________ Sample No. 1* 2 3 4* 5 6 7 8 __________________________________________________________________________ Resin composition EPIKOTE 828 100 100 100 100 100 100 EPIKOTE 1002 100 100 100 Anhydride A 87 87 87 87 87 87 Anhydride B 20 Phenol Resin 15 BDMA 1.5 1.5 1.5 1.5 1.5 1.5 TPP 1.0 1.0 Filler Silica 80 80 80 80 80 80 Fe-O 2 1 Cordierite 18 19 Composite particles CoA-Fe-O 20 10 20 20 CoD-Fe-O 20 10 Color of Mark brown black black red brown brown black black Visibility Once C B B D C C B B Five times B A A D B B A A __________________________________________________________________________ *Comparative sample EXAMPLE 9 Example 8 was repeated in the same manner as described except that CoB-T-W, CoB-Ti-Y or CoB-Nb-W (obtained in Example 3) was used as the composite particles. The results are summarized in Table 10. EXAMPLE 10 Example 8 was repeated in the same manner as described except that CoA-T-W (obtained in Example 2), CoB-T-W (obtained in Example 3), CoC-Ti-Y (obtained in Example 6) or CoD-Ti-W (obtained in Example 6) was used as the composite particles. The results are summarized in Table 11. Comparative samples gave gray marks while the samples according to the present invention gave black or grayish black marks. EXAMPLE 11 Example 8 was repeated in the same manner as described except that CoA-T-W, ZeA-Ti-W, ZrA-Ti-W, CaA-Ti-W or CoA-Nb-W (obtained in Example 4) was used as the composite particles. The results are summarized in Table 12. Comparative samples Nos. 1, 3, 5, 7 and 9 gave gray marks while the samples Nos. 2, 6 and 11 according to the present invention gave black marks. The samples Nos. 4, 8 and 10 of the present invention gave grayish black marks. EXAMPLE 12 Example 8 was repeated in the same manner as described except that CoB-T-W, ZeB-Ti-W, ZrB-Ti-W, CaB-Ti-W or CoB-Nb-W (obtained in Example 5) was used as the composite particles. The results are summarized in Table 13. Comparative samples Nos. 1, 3, 5, 7 and 9 gave gray marks while the samples Nos. 2, 6, 10 and 11 according to the present invention gave black marks. The samples Nos. 4 and 8 of the present invention gave gray marks. In Tables 10-13, the symbol "*" indicates comparative sample. TABLE 10 __________________________________________________________________________ Sample No. 1* 2 3* 4 5* 6 7 __________________________________________________________________________ Resin composition EPIKOTE 828 100 100 100 100 100 100 EPIKOTE 1002 100 Anhydride A 87 87 87 87 87 87 Anhydride B 20 BDMA 1.5 1.5 1.5 1.5 1.5 1.5 TPP 1.0 Filler Silica 80 80 80 80 80 80 80 Ti-W 2 Ti-Y 2 Nb-W 2 Cordierite 18 18 18 Composite particles CoB-Ti-W 20 20 CoB-Ti-Y 20 CoB-Nb-O 20 Color of Mark gray black gray black gray gray- black black Visibility Once D B D B D C B Five times C A C A C B A __________________________________________________________________________ TABLE 11 __________________________________________________________________________ Sample No. 1* 2 3 4 5 6* 7 8 9 10 11 12 __________________________________________________________________________ Resin composition EPIKOTE 828 100 100 100 100 100 100 100 100 100 100 EPIKOTE 1002 100 100 Anhydride A 87 87 87 87 87 87 87 87 87 87 Anhydride B 20 Phenol resin 15 BDMA 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 TPP 1.0 1.0 Filler Silica 80 80 80 80 80 80 80 80 80 80 50 50 Ti-W 5 2 Cordierite 45 18 Composite particles CoA-Ti-W 50 20 CoB-Ti-W 50 20 50 50 CoC-Ti-W 50 20 CoD-Ti-W 50 20 Visibility Once C C C B B D C C C B B B Five times B A B A A C B B B A A A __________________________________________________________________________ TABLE 12 __________________________________________________________________________ Sample No. 1* 2 3* 4 5* 6 7* 8 9* 10 11 __________________________________________________________________________ Resin composition EPIKOTE 828 100 100 100 100 100 100 100 100 100 100 EPIKOTE 1002 100 Anhydride A 87 87 87 87 87 87 87 87 87 87 Anhydride B 20 BDMA 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 TPP 1.0 Filler Silica 80 80 80 80 80 80 80 80 80 80 80 Ti-W 2 2 2 2 10 Nb-O 2 Cordierite 18 18 Zeolite 18 Zr-silicate 18 Ca-silicate 18 Composite particles CoA-Ti-W 20 20 ZeA-Ti-W 20 ZrA-Ti-W 20 CaA-Ti-W 20 CoA-Nb-O 20 Visibility Once D C D C D C D C D C C Five times C B C B C B C B C B B __________________________________________________________________________ TABLE 13 __________________________________________________________________________ Sample No. 1* 2 3* 4 5* 6 7* 8 9* 10 11 __________________________________________________________________________ Resin composition EPIKOTE 828 100 100 100 100 100 100 100 100 100 100 EPIKOTE 1002 100 Anhydride A 87 87 87 87 87 87 87 87 87 87 Anhydride B 20 BDMA 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 TPP 1.0 Filler Silica 80 80 80 80 80 80 80 80 80 80 80 Ti-W 2 2 2 2 Nb-O 2 Cordierite 18 18 Zeolite 18 Zr-silicate 18 Ca-silicate 18 Composite particles CoA-Ti-W 20 20 ZeA-Ti-W 20 ZrA-Ti-W 20 CaA-Ti-W 20 CoA-Nb-O 20 Visibility Once D B D C D B D C D C B Five times C A C B C A C B C B A __________________________________________________________________________ EXAMPLE 13 Preparation of Composite Particles by Dry-Mixing Method (Method A) In accordance with the Method A described in Example 1, cupric oxalate and cordierite were processed to obtain composite particles CoA-Cu-1 having an average particle diameter of 10 .mu.m and a weight ratio of cupric oxalate to cordierite of 3:17 and CoA-Cu-2 having an average particle diameter of 15 .mu.m and a weight ratio of cupric oxalate to cordierite of 3:7. Preparation of composite Particles by Precipitation Method Into a three-necked flask were charged 34 g of cordierite (the same as used in Example 1) and 100 ml of water and the mixture was heated to 50.degree. C. With stirring, a solution of anhydrous cupric sulfate (5.8 g) dissolved in 60 ml of water was poured dropwise into the flask. Then, a solution of oxalic acid dihydride (7.2 g) dissolved in 50 ml of distilled water was added dropwise to the mixture in the flask with stirring. The resulting mixture was stirred for 30 minutes and a greater part of the water was removed in vacuo. The remaining mixture was filtered and the solids phase was dried at 110.degree. C., thereby to obtain composite particles CoC-Cu-1 having an average particle diameter of 15 .mu.m and a weight ratio of cupric oxalate to cordierite of 3:17. The above procedure was repeated in the same manner as described except that the amounts of the cordierite, anhydrous cupric sulfate and oxalic acid dihydride were changed to 14 g, 5.8 g and 7.2 g, respectively, thereby to obtain composite particles CoC-Cu-2 having an average particle diameter of 10 .mu.m and a weight ratio of cupric oxalate to cordierite of 3:7. Using the thus obtained composite particles, Example 8 was repeated in the same manner as described. The results are shown in Table 14. TABLE 14 ______________________________________ Sample No. 1* 2 3 4* 5 6 ______________________________________ Resin Composition EPIKOTE 100 100 100 100 100 100 828 Anhydride A 87 87 87 87 87 87 BDMA 1.5 1.5 1.5 1.5 1.5 1.5 Silica 50 50 50 50 50 50 Cu oxalate 7.5 15 Cordierite 42.5 35 CoA-Cu-1 50 CoA-Cu-2 50 CoC-Cu-1 50 CoC-Cu-2 50 Color of -- gray gray- gray gray- black Mark black glack Visibility Once D C B D B B Five times D B B C B A ______________________________________ *Comparative sample The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all the changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.