① Name and Properties

• English Name: Polymerized Rosin
• Alternative English Names: Rosin, Polymerised
• CAS Number: 65997-05-9
• Physical Properties: Yellow-brown amorphous solid. Polymerized rosin is primarily composed of dimers, along with a mixture of rosin and rosin hydrocarbons. It is characterized by light color, high softening point, non-crystallinity, high acid value, low hot water-soluble content, good oil solubility, and light lead acetate discoloration. Dimers account for 20% to 50% and are relatively stable, resisting oxidation. It is soluble in organic solvents such as toluene, gasoline, petroleum ether, chloroform, and dichloroethane.

② Chemical Formula or Molecular Formula and Structural Formula

• Molecular Formula: C40H60O4 (Note: This is a simplified or representative molecular formula, as polymerized rosin is a mixture, so the specific structure may vary depending on the degree of polymerization.)

③ Physical and Chemical Properties and Quality Indicators

• Softening Point: 90 to 120°C (This is the temperature range at which polymerized rosin begins to flow when heated.)
• Acid Value: 150 mg KOH/g (This is a measure of the acidic component content in polymerized rosin, typically expressed as the milligrams of potassium hydroxide required to neutralize 1 gram of the sample.)
• Other Quality Indicators: See the provided table.

④ Main Applications

• As a Tackifying Resin: Used in hot-melt, pressure-sensitive, and solvent-based adhesives to enhance adhesion and provide reinforcement effects.
• Improving Bonding Strength: Enhances the heat sensitivity of adhesive tapes and improves bonding strength.
• Reducing Product Costs: Can partially replace other costlier resins, such as terpene resin and petroleum resin.
• EVA Hot-Melt Adhesive: Provides optimal comprehensive performance when used in EVA hot-melt adhesives. The usage amount is typically optimized based on specific applications and desired properties, but 50% usage is often recommended, or 120 parts by mass for maximum peel strength.