Tokan Material Technology Co., Ltd.

Tomatec Co., Ltd.

Tatsuo Matoda

Shigeru Suzuki

Akira Ishiko

Jun Fujiwara

Taketo Shinchi

A Cu—Cr—Zn—O based pigment includes a Cu—Cr—O based oxide and Zn derived from a zinc oxide added as a modifying oxide and solid-dissolved in the Cu—Cr—O based oxide. The Cu—Cr—Zn—O based pigment has a composition formula of aCuO·bCrO·cZnO (mol %), in which 0.1≤c≤5, 45≤a+c≤55, and 45≤b≤55 (a+b+c=100).

Cu—Cr—Zn—O based pigment

The present invention is directed to a bismuth oxide-based additive for laser marking containing oxygen-deficient bismuth oxide represented by the general formula: BiO(provided that x is 0.01 or more and 0.3 or less and x represents the amount of oxygen deficiency calculated according to the formula: x=3&#x2212;O/Bi&#xd7;2 from the ratio (O/Bi) of the peak area attributed to the 1s electrons of oxygen bonded to bismuth to the peak area attributed to the 4f electrons of bismuth obtained by X-ray photoelectron spectrometry), which enables marking with excellent blackness and contrast without causing undesirable coloration of a resin composition regardless of the type or shape of a resin to be used.

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Osaka, Japan

Tatsuo Matoda