RUBBER/FIBER ADHESION TREATING AGENT AND SYNTHETIC FIBER CORD FOR RUBBER REINFORCEMENT USING SAME

An object of the present invention is to provide an adhesive treatment agent for rubber and fiber and a synthetic fiber cord for rubber reinforcement, which are composed of an adhesive treatment agent not containing resorcin or formalin and using a raw material advantageous for reducing an environmental load, which exhibit an initial adhesive force equal to or more than that of conventional RFLs, which are less likely to cause adhesive deterioration under a high temperature for a long time in a state of being embedded in rubber, and which have suppressed strength deterioration when repeatedly stretched and compressed in rubber. An object of the present invention is also to provide an adhesive treatment agent for rubber and fiber and a synthetic fiber cord for rubber reinforcement which have a good storage stability of an adhesive treatment agent, can suppress generation of a resin solidified product in a dipping process, and have a good productivity. The gist of the present invention is an adhesive treatment agent for rubber and fiber, the adhesive treatment agent containing at least: a lignin derivative (A); a water-soluble or water-dispersible crosslinking agent (B); and a rubber latex (C), the adhesive treatment agent not containing a resorcin-formaldehyde resin, wherein the lignin derivative (A) has a number average molecular weight of 10,000 to 60,000 and a weight average molecular weight of 80,000 to 130,000.