Anti-contamination agent composition

An anti-contamination agent composition for preventing pitch contamination in a dry part of a paper-making process, comprising:

• a linear polysiloxane compound represented by following formula (1), and
• a cyclic siloxane compound,
• wherein at least one of the substituents R1 in one molecule are an amino-modified group represented by following formula (2);
• the cyclic siloxane compound is at least one compound selected from the group consisting of octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane;
• a blending quantity of the cyclic siloxane compound is 15 to 20,000 ppm;
• and
• a blending mass ratio of the cyclic siloxane compound and the polysiloxane compound is 1:5 to 50,000:
• wherein substituents R1 represent a hydrogen atom, an alkyl group, a methylphenyl group, a polyether group, a higher fatty acid ester group, an amino-modified group, an epoxy-modified group, a carboxy group, a phenol group, a mercapto group, a carbinol group, or a methacryl group, and the number n of repeating siloxane units represents an integer from 20 to 1430, and
• wherein substituents R2 and R3 each independently represent an alkylene group having 1 to 6 carbon atoms, and the number m of repeating aminoalkylene units represents 1.