METAL CORROSION INHIBITOR

摘要

PROBLEM TO BE SOLVED: To enhance metal corrosion inhibiting ability by incorporating a polyaspartic acid modification obtd. by modifying a polyaspartic acid structure with cystine. SOLUTION: The metal corrosion inhibitor contains a polyaspartic acid modification obtd. by modifying a polyaspartic acid structure contg.α,β-amido bonds at random with cystine and carrying out hydrolysis. The molar ratio between cysteine used for modification and aspartic acid residues to be modified is (1-20):100, preferably (2-10):100. The polyaspartic acid modification has >=99% barium sulfate precipitation inhibiting ability and the inequality 92-4.3×(molar ratio of cystine)<(barium sulfate precipitation inhibiting ability) is satisfied. The molar ratio of cystine is expressed by 100×(molar number of cystine used for modification)/(molar number of aspartic acid residues). This modification is obtained by heating and melting mono-ammonium maleate and reacting it with cystine.