Abstract: A binder is used for binding foundry sand to form a mold and a core for casting, and consists of a condensation-reactive first compound (resin) having at least one methylol group in a molecule, amounting to 100 parts by weight. An additive component is added to the resin to improve the strength and the sand removability of the mold and the core while improving the production yield of the mold and the core. The additive component includes at least one of calcium hydroxide and barium hydroxide in particle form. The particle surface of the at least one of calcium hydroxide and barium hydroxide is coated with a second compound having a melting point not lower than 50.degree. C. and a boiling point ranging from 250.degree. to 400.degree. C., the second compound ranging from 0.5 to 35 parts by weight.

Abstract: A sulfur-curable acrylic rubber composition is provided which comprises [I] 100 parts of an acrylic rubber resulting from the copolymerization in the presence of a radical initiator of (1) 30 to 89.5% by weight of at least one alkyl acrylate with the alkyl group containing 1 to 8 carbon atoms, (2) 0.5 to 10% by weight of at least one monomer of the general formula ##STR1## wherein R.sub.1 represents a hydrogen atom or a methyl group, and R.sub.2 and R.sub.3, independently from each other, represent an alkyl group containing 1 to 3 carbon atoms, (3) 10 to 60% by weight of at least one alkoxyalkyl acrylate with the alkoxy group containing 1 to 4 carbon atoms and the alkylene group containing 1 to 4 carbon atoms, and 0 to 30% by weight of at least one of monovinyl and monovinylidene unsaturated compounds other than the said compounds; and [II] 1 to 5 parts by weight of a metal compound, and [III] 0.2 to 5 parts by weight, as sulfur, of at least one of sulfur and sulfur-containing organic compounds.

Abstract: A process for producing a sulfur-curable acrylic rubber is provided which comprises radical-copolymerizing (1) an alkyl acrylate with (2) an alkenyl acrylate or methacrylate, or radical-copolymerizing (1) an alkyl acrylate, (2) an alkenyl acrylate or methacrylate, (3) an alkoxyalkyl acrylate and optionally (4) acrylonitrile. These acrylic rubbers can be cured at a rate as fast as those for curing diene-type rubbers, and the cured products exhibit superior properties without long heat-treatment after curing.

Abstract: A process for producing a sulfur-curable acrylic rubber is provided which comprises radical-copolymerizing (1) an alkyl acrylate with (2) an alkenyl acrylate or methacrylate, or radical-copolymerizing (1) an alkyl acrylate, (2) an alkenyl acrylate or methacrylate, (3) an alkoxyalkyl acrylate and optionally (4) acrylonitrile. These acrylic rubbers can be cured at a rate as fast as those for curing diene-type rubbers, and the cured products exhibit superior properties without long heat-treatment after curing.