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Thermal migration staining belongs to hidden high-temperature induced defect, which frequently occurs in thermal lamination paper, heat-seal packaging paper and thermal transfer base paper. Under continuous heating and thermal pressure, soluble pigments, sizing components and low-molecular additives inside paper will migrate along temperature gradient and gather on the paper surface, forming irregular color spots and cloudy stains. Such defects rarely appear at room temperature inspection, and gradually emerge after thermal processing, leading to printed pattern distortion and uneven surface tone. Conventional color fixing technologies only restrain normal-temperature bleeding and cannot limit molecular migration driven by thermal energy. After heating, internal components still diffuse outward, contaminating contact film and printed layers, resulting in a large number of post-processing defective products.Shandong Ludao Energy Technology Co., Ltd. develops anti-thermal migration staining modification schemes. By building interception networks inside fiber gaps to lock active small-molecule substances, we cut off the thermal migration path of additives and pigments. The technology effectively avoids surface stain formation after heating treatment, guarantees uniform appearance and stable printing performance of paper after thermal processing, and reduces the rejection rate of thermal composite and heat-sealed products.