Polyarylene Sulfide Resin Composition for Post-Annealing Epoxy Adhesion

The patent introduces an olefin wax containing carboxyl and carboxylic acid anhydride groups as an intermediary substance between the polyarylene sulfide resin and epoxy resin. This wax acts as a coupling agent that facilitates bonding between the two resins, improving epoxy adhesiveness without requiring direct complex blending of the resins themselves. The wax contains both polar groups (carboxyl and carboxylic acid anhydride) that can interact with both materials, serving as a mediating layer.

The patent creates a composite resin composition by combining polyarylene sulfide resin, epoxy resin, and olefin wax in specific ratios. This composite approach allows the individual components to maintain their beneficial properties while working together to achieve improved epoxy adhesiveness. The specific composition ranges (0.1-10 parts epoxy resin per 100 parts polyarylene sulfide resin, and 0.01-5 parts olefin wax per 100 parts polyarylene sulfide resin) optimize the composite performance.

The patent applies preliminary action by incorporating the olefin wax into the resin composition before molding and annealing. The wax is pre-distributed throughout the resin matrix, creating a protective network that will maintain epoxy adhesiveness even when subsequent annealing treatment is applied. This preliminary incorporation ensures that the adhesion-promoting components are already in place before the stress-relief process begins.

The olefin wax acts as a cushioning agent that protects the epoxy resin interface from the detrimental effects of annealing treatment. The wax's thermal properties and chemical structure provide a buffer that allows the annealing process to relieve internal stresses without causing excessive degradation of the epoxy bonding interface. This beforehand cushioning maintains adhesion strength despite the thermal cycling involved in annealing.

The patent carefully controls the acid value parameter of the olefin wax within a specific range (65-150 mg KOH/g) to optimize bonding strength while managing processing sensitivity. By specifying this parameter range, the patent identifies the optimal balance between adhesion promotion and processability. The acid value directly correlates with the concentration of polar groups available for bonding, so controlling this parameter allows tuning of both adhesion and processing characteristics.

The patent applies local quality by concentrating the olefin wax at the interface between the polyarylene sulfide resin and epoxy resin, rather than uniformly distributing it throughout the entire composition. The wax preferentially migrates to and accumulates at the bonding interface during processing, where it exerts its maximum adhesion-promoting effect. This localized concentration allows high bonding strength with minimal overall wax content, reducing processing sensitivity.