Process for producing modified polypropylene resin

There is provided a process for producing a modified polypropylene resin, which comprises the steps of mixing the following components (A) to (D), and reacting them with one another:

• (A) 100 parts by weight of a polypropylene resin,
• (B) 0.1 to 30 parts by weight of a compound having a bond or a functional group selected from the group consisting of a non-aromatic carbon-carbon multiple bond, an oxirane group and a derived carboxyl group,
• (C) 0.001 to 30 parts by weight of a compound having at least two functional groups reactive to a carboxyl group, and
• (D) 0.01 to 20 parts by weight of an organic peroxide having a decomposition temperature of from 50 to 120 C., at which temperature a half-life of the organic peroxide is 1 minute.