Colorant compositions for themoplastic olefin elastomers

Abstract: Described are colorant compositions for thermoplastic olefin elastomers. They are composed of a pigment; and silicon oxide or a compound containing silicon oxide and/or methylhydrogenpolysiloxane.

Description: BACKGROUND OF THE INVENTION 1) Field of the Invention This invention relates to colorants for thermoplastic olefin elastomers (hereinafter abbreviated as "TPO"), and more specifically to colorant compositions usable when TPO is colored and formed through a calender roll, mixing roll or embossing roll, or when TPO is similarly processed through a T-die or the like. 2) Description of the Related Art JP-A 58-69233 discloses a masterbatch for coloring a polyolefin, comprising a pigment, a carrier resin and an additive. TPOs have heretofore been formed into a variety of products such as films, sheets or the like while being colored with various organic or inorganic pigments. Coloration of TPO with a conventional colorant, however, results in the deposition of its pigment on a roll or die surface (this is called "plateout") so that the workability is impaired substantially. SUMMARY OF THE INVENTION An object of this invention is therefore to overcome the drawback of the conventional art, thereby to provide a TPO colorant free of plateout. The above object has been attained by the present invention described hereinafter. The present invention therefore provides a colorant composition for a TPO, comprising: 100 parts by weight of a pigment; 0.5-100.0 parts by weight of silicon oxide or a compound containing silicon oxide; and 0.1-20.0 parts by weight of methylhydrogenpolysiloxane. Owing to the incorporation of 0.5-100.0 parts by weight of the SiO 2 -containing compound and 0.1-20.0 parts by weight of the pigment, the colorant composition for the TPO does not develop plateout, that is, the phenomenon that the pigment deposits on a roll or die surface. DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS The present invention will hereinafter be described more specifically by preferred embodiments. Examples of the SiO 2 -containing compound usable in the present invention may include silicic acids such as silicic anhydride, silicic hydrate, ultra-fine powder; and silicic-acid-containing compounds such as aluminum silicate, aluminum silicate hydrate, magnesium silicate hydrate and other silicates including calcium silicate and sodium silicate. Methylhydrogenpolysiloxane usable in the present invention cures under heat and/or by a suitable catalyst, thereby forming hydrophobic coating. Examples of the pigment, the remaining raw material employed in the colorant composition of the present invention, include organic pigments such as azo pigments, phthalocyanine pigments, nitro or nitroso pigments, basic dyes, acid dyes and mordant dyes; inorganic pigments such as titanium oxide, chrome yellow, chrome vermilion, ultramarine and red oxide; and carbon black. In addition, examples of substances usable in the present invention as needed include a carrier resin for the provision of a masterbatch such as polyethylene, polypropylene or TPO; a high-molecular substance which can be added to improve the dispersion of the pigment, the workability during production and various physical properties, such as wax, low-molecular-weight polyethylene, polystyrene, a styrene copolymer, a petroleum resin and rosin; a stabilizer for improved stability such as a metallic soap, an organic acid salt or an organometal compound; and various other additives such as a dispersing agent, an antioxidant and an ultraviolet absorber. The colorant composition of the present invention can take, for example, the following forms: (1) A wettable colorant composition composed of a pigment and a wax. In this case, the colorant composition preferably comprises 100 parts by weight of the pigment, 0.5-100.0 parts by weight of an SiO 2 -containing compound, and 0.1-20.0 parts by weight of methylhydrogenpolysiloxane, and 20-500 parts by weight of the wax. (2) A powdery colorant composition composed of a pigment and a metallic soap. In this case, the colorant composition preferably comprises 100 parts by weight of the pigment, 0.5-100.0 parts by weight of an SiO 2 -containing compound and 0.1-20.0 parts by weight of methylhydrogenpolysiloxane, and 20-500 parts by weight of the metallic soap. (3) A masterbatch composed of a pigment, a dispersing agent and a carrier resin such as a thermoplastic resin, for example, polyethylene, polypropylene or TPO. In this case, the masterbatch preferably comprises 100 parts by weight of a colorant composition and 30-1,000 parts by weight of the carrier resin, said colorant composition being formed of 100 parts by weight of the pigment, 0.5-100.0 parts by weight of an SiO 2 -containing compound and 0.1-20.0 parts by weight of methylhydrogenpolysiloxane, 20-500 parts by weight of the dispersing agent. Each of these colorant compositions for TPO according to the present invention can be produced by adding an SiO 2 -containing compound and methylhydrogenpolysiloxane as much as desired upon production of a conventionally-known colorant and dispersing the same in a usual manner. Incidentally, when the composition is manufactured, it is preferred to bring the pigment into contact with the SiO 2 -containing compound and methylhydrogenpolysiloxane as much as possible. The present invention will hereinafter be described specifically by the following examples and comparative examples, in which all designations of "part" or "parts" and "%" mean part or parts by weight and wt.% unless otherwise specifically indicated. Reference Example 1 Quinacridone red 45 parts Silicon oxide ("Solex CM", trade name, product of Tokuyama Soda Co., Ltd.) 5 parts Polyethylene wax ("Sunwax 151P", trade name, product of Sanyo Chemical Industries, Ltd.) 50 parts The above raw materials were kneaded through a heated three-roll mill, whereby a wettable colorant composition was obtained. Comparative Example 1 Quinacridone red 45 parts Calcium carbonate ("NS-100", trade name; product of Nitto Funka Kogyo K.K.) 5 parts Polyethylene wax ("Sunwax 151P", trade name; product of Sanyo Chemical Industries, Ltd.) 50 parts The above raw materials were kneaded through a heated three-roll mill, whereby a wettable colorant composition was obtained as a comparative example. The colorant compositions obtained in the above reference example and comparative example were each added in an amount of 3 parts to 100 parts of TPO ("Mirastomer 5030", trade name; product of Mitsui Petrochemical Industries, Ltd.), followed by kneading for 4 minutes through a two-roll mill of 180°C. After the removal of the resultant colored sheet, plateout on the roll was cleaned by a cleaning compound (a white PVC compound). The degree of coloration of the cleaning compound was compared. Results: Degree of coloration of the cleaning compound (compared with the blank) Reference example 1 Color difference (ΔE) change) 0.2 (no substantial Comparative Example 1 Color difference (ΔE) 33.6 (colored in pink) Reference Example 2 Titanium white ("R-820 Titanium White", trade name; product of Ishihara Sangyo Kaisha, Ltd.) 50 parts Silicon oxide ("Silton A", trade name; product of Mizusawa Chemical Co., Ltd.) 10 parts Polyethylene resin ("Suntec F2270P", trade name; product of Asahi Chemical Industry, Ltd.) 40 parts The raw materials described above were kneaded through an extruder, whereby a masterbatch was obtained. Comparative Example 2 Titanium white ("R-820 Titanium White", trade name; product of Ishihara Sangyo Kaisha, Ltd.) 50 parts Talc ("Talc P", trade name; product of Shiraishi Calcium Co., Ltd.) 10 parts Polyethylene resin ("Suntec F2270P", trade name; product of Asahi Chemical Industry, Ltd.) 40 parts The raw materials described above were kneaded through an extruder, whereby a masterbatch was obtained as a comparative example. The masterbatches obtained in the above reference example and comparative example were each added in an amount of 5.0 parts to 100 parts of TPO ("Mirastomer 6030", trade name; product of Mitsui Petrochemical Industries, Ltd.), followed by kneading for 4 minutes through a two-roll mill of 180°C. After the removal of the resultant colored sheet, plateout on the surface of the roll was observed visually to compare its whiteness. Results (visual judgment) Reference example 2 No white plateout was observed. Comparative Example 2 Marked white plateout was observed. Reference Example 3 Phthalocyanine blue 50 parts Calcium silicate ("NW-7P", trade name; product of Mizusawa Chemical Co., Ltd.) 20 parts Calcium stearate 30 parts The raw materials described above were mixed in a high-speed mixer, whereby a colorant composition was obtained in the form of a powder. Comparative Example 3 Phthalocyanine blue 50 parts Calcium carbonate ("NS-400", trade name; product of Nitto Funka Kogyo K.K.) 20 parts Calcium stearate 30 parts The raw materials described above were mixed in a high-speed mixer, whereby a colorant composition as a comparative example was obtained in the form of powder. The colorant compositions obtained in the above reference example and comparative example were each added in an amount of 50 parts to 5,000 parts of TPO ("Mirastomer 5030", trade name; product of Mitsui Petrochemical Industries, Ltd.), followed by mixing in the high-speed mixer. The resulting mixture was continuously extruded through a T-die extruder set at 190°C, whereby a film was formed. Plateout on the die was thereafter observed visually to compare the degree of coloration of the die. Results (visual judgment) Reference example 3 The die was practically uncolored. Comparative Example 3 The die was markedly colored in blue. Reference Example 4 Quinacridone red 45 parts Methylhydrogenpolysiloxane ("Silicone SH1107", trade name; product of Toray Silicone Co., Ltd.) 4 parts Polyethylene wax ("Sunwax 151P", trade name; product of Sanyo Chemical Industries, Ltd.) 51 parts The raw materials described above were kneaded through a heated three-roll mill, whereby a wettable colorant composition was obtained. Comparative Example 4 Quinacridone red 45 parts Calcium carbonate ("NS-100", trade name; product of Nitto Funka Kogyo K.K.) 5 parts Polyethylene wax ("Sunwax 151P", trade name; product of Sanyo Chemical Industries, Ltd.) 50 parts The raw materials described above were kneaded through a heated three-roll mill, whereby a wettable colorant composition as a comparative example was obtained. The colorant compositions obtained in the above reference example and comparative example were each added in an amount of 3.0 parts to 100 parts of TPO ("Mirastomer 5030", trade name; product of Mitsui Petrochemical Industries, Ltd.), followed by kneading for 4 minutes through a two-roll mill of 180°C. After a colored sheet was removed, plateout on the roll was cleaned by a cleaning compound (a white PVC compound). The degree of coloration of the cleaning compound was compared. Results: degree of coloration of the cleaning compound (compared with the blank) Reference example 4 Color difference (ΔE) change) 0.1 (no substantial Comparative Example 4 Color difference (ΔE) 33.6 (colored in pink) Reference Example 5 Titanium white ("R-820 Titanium White", trade name; product of Ishihara Sangyo Kaisha, Ltd.) 50 parts Methylhydrogenpolysiloxane ("Silicone SH1107", trade name; product of Toray Silicone Co., Ltd.) 5 parts Polyethylene resin ("Suntec F2270P", trade name; product of Asahi Chemical Industry, Ltd.) 45 parts The raw materials described above were kneaded through an extruder, whereby a masterbatch was obtained. Comparative Example 5 Titanium white ("R-820 Titanium White", trade name; product of Ishihara Sangyo Kaisha, Ltd.) 50 parts Polyethylene resin ("Suntec F2270P", trade name; product of Asahi Chemical Industry, Ltd.) 50 parts The raw materials described above were kneaded through an extruder, whereby a masterbatch as a comparative example was obtained. The masterbatches obtained in the above reference example and comparative example were each added in an amount of 5.0 parts to 100 parts of TPO ("Mirastomer 6030", trade name; product of Mitsui Petrochemical Industries, Ltd.), followed by kneading for 4 minutes through a two-roll mill of 180°C. After the removal of the resultant colored sheet, plateout on the surface of the roll was observed visually to compare its whiteness. Results (visual judgment) Reference example 5 No white plateout was observed. Comparative Example 5 Marked white plateout was observed. Reference Example 6 Phthalocyanine blue 50 parts Methylhydrogenpolysiloxane "Silicone Oil KF99", trade name; product of Toray Silicone Co., Ltd.) 3 parts Calcium stearate 47 parts The raw materials described above were mixed in a high-speed mixer, whereby a colorant composition was obtained in the form of a powder. Comparative Example 6 Phthalocyanine blue 50 parts Calcium carbonate ("NS-400", trade name; product of Nitto Funka Kogyo K.K.) 20 parts Calcium stearate 30 parts The raw materials described above were mixed in a high-speed mixer, whereby a colorant composition as a comparative example was obtained in the form of a powder. The colorant compositions obtained in the above reference example and comparative example were each added in an amount of 50 parts to 5,000 parts of TPO ("Mirastomer 5030", trade name; product of Mitsui Petrochemical Industries, Ltd.), followed by mixing in the high-speed mixer. The resulting mixture was continuously extruded through a T-die extruder set at 190°C, whereby a film was formed. Plateout on the die was thereafter observed visually to compare the degree of coloration of the die. Results (visual judgment) Reference example 6 The die was practically uncolored. Comparative Example 6 The die was markedly colored in blue. Example 7 Quinacridone red 45 parts Silicon oxide ("Solex CM", trade name; product of Tokuyama Soda Co., Ltd.) 5 parts Methylhydrogenpolysiloxane ("Silicone SH1107", trade name; product of Toray Silicone Co., Ltd.) 4 parts Polyethylene wax ("Sunwax 151P", trade name; product of Sanyo Chemical Industries, Ltd.) 46 parts The raw materials described above were kneaded through a heated three-roll mill, whereby a wettable colorant composition of the present invention was obtained. Comparative Example 7 Quinacridone red 45 parts Calcium carbonate ("NS-100", trade name; product of Nitto Funka Kogyo K.K.) 5 parts Polyethylene wax ("Sunwax 151P", trade name; product of Sanyo Chemical Industries, Ltd.) 50 parts The raw materials described above were kneaded through a hot three-roll mill, whereby a wettable colorant composition as a comparative example was obtained. The colorant compositions obtained in the above example and comparative example were each added in an amount of 3.0 parts to 100 parts of TPO ("Mirastomer 5030", trade name; product of Mitsui Petrochemical Industries, Ltd.), followed by kneading for 4 minutes through a two-roll mill of 180°C. After the removal of the resultant colored sheet, plateout on the roll was cleaned by a cleaning compound (a white PVC compound). The degree of coloration of the cleaning compound was compared. Results: Degree of coloration of the cleaning compound (compared with the blank) Example 7 Color difference (ΔE) change) 0.1 (no substantial Comparative Example 7 Color difference (ΔE) 33.6 (colored in pink) Example 8 Titanium white ("R-820 Titanium White", trade name; product of Ishihara Sangyo Kaisha, Ltd.) 50 parts Silicon oxide ("Silton A", trade name; product of Mizusawa Chemical Co., Ltd.) 10 parts Methylhydrogenpolysiloxane ("Silicone SH1107",trade name; product of Toray Silicone Co., Ltd.) 5 parts Polyethylene resin ("Suntec F2270P", trade name; product of Asahi Chemical Industry, Ltd.) 35 parts The raw materials described above were kneaded through an extruder, whereby a masterbatch of the present invention was obtained. Comparative Example 8 Titanium white ("R-820 Titanium White", trade name; product of Ishihara Sangyo Kaisha, Ltd.) 50 parts Talc ("Talc P", trade name; product of Shiraishi Calcium Co., Ltd.) 10 parts Polyethylene resin ("Suntec F2270P", trade name; product of Asahi Chemical Industry, Ltd.) 40 parts The raw materials described above were kneaded through an extruder, whereby a masterbatch as a comparative example was obtained. The masterbatches obtained in the above example and comparative example were each added in an amount of 5.0 parts to 100 parts of TPO ("Mirastomer 6030", trade name; product of Mitsui Petrochemical Industries, Ltd.), followed by kneading for 4 minutes through a two-roll mill of 180°C. After the removal of the resultant colored sheet, plateout on the surface of the roll was observed visually to compare its whiteness. Results (visual judgment) Example 8 No white plateout was observed. Comparative Example 8 Marked white plateout was observed. Example 9 Phthalocyanine blue 50 parts Calcium silicate ("NW-7P", trade name; product of Mizusawa Chemical Co., Ltd.) 20 parts Methylhydrogenpolysiloxane "Silicone Oil KF99", trade name; product of Toray Silicone Co., Ltd.) 3 parts Calcium stearate 27 parts The raw materials described above were mixed in a high-speed mixer, whereby a colorant composition of the present invention was obtained in the form of a powder. Comparative Example 9 Phthalocyanine blue 50 parts Calcium carbonate ("NS-400", trade name; product of Nitto Funka Kogyo K.K.) 20 parts Calcium stearate 30 parts The raw materials described above were mixed in a high-speed mixer, whereby a colorant composition as a comparative example was obtained in the form of powder. The colorant compositions obtained in the above example and comparative example were each added in an amount of 50 parts to 5,000 parts of TPO ("Mirastomer 5030", trade name; product of Mitsui Petrochemical Industries, Ltd.), followed by mixing in the high-speed mixer. The resulting mixture was continuously extruded through a T-die extruder set at 190°C, whereby a film was formed. Plateout on the die was thereafter observed visually to compare the degree of coloration of the die. Results (visual judgment) Example 9 The die was practically uncolored. Comparative Example 9 The die was markedly colored in blue.

Claims: A colorant composition for a thermoplastic olefin elastomer, comprising: 100 parts by weight of a pigment; and 0.5-100.0 parts by weight of silicon oxide or a compound containing silicon oxide and 0.1-20.0 parts by weight of methylhydrogenpolysiloxane. The colorant composition of claim 1, further comprising 20-500 parts by weight of a wax. The colorant composition of claim 1, further comprising 20-500 parts by weight of a metallic soap. The colorant composition of claim 1, further comprising 20-500 parts by weight of a dispersant and 30-1,000 parts by weight of a carrier resin. The colorant composition of claim 4, wherein the carrier resin is a thermoplastic resin. The colorant composition of claim 1, wherein the compound containing silicon oxide is selected from the group consisting of silicic anhydride, silicic hydrate, aluminum silicate, aluminum silicate hydrate, magnesium silicate hydrate and calcium silicate.

Inventors: SAKAMOTO MORIHISA, TACHIHARA ISAO, SAKAMOTO, MORIHISA, TACHIHARA, ISAO
Applicants: DAINICHISEIKA COLOR CHEM, DAINICHISEIKA COLOR
Application year: 1992
Main classification: C09B67
IPC codes: C08K5, C09B67, C08K3