Rosin acid is a natural product, and its synthetic surfactants generally possess good ecological properties, meeting the "green" surfactants' requirement for "raw material greening." Research on using rosin to synthesize surfactants began abroad in the 1920s, with the synthesis of rosin acid estersulfonates and rosin amines polyoxyethylene ethers in the 1960s. After the 1990s, due to the scarcity of rosin resources overseas, research on synthesizing new surfactants from rosin did not advance significantly, and instead focused on the application studies of rosin-based surfactants. China has conducted extensive research in this area, synthesizing numerous new surfactants.

Rosin acid alkali metal salts are one of the earlier types of surfactants derived from rosin acid, produced by neutralizing rosin acid with alkali. Sodium rosinate is widely used in the production of laundry soap, enhancing soap foam properties and preventing rancidity of fatty acids. However, due to price influences, its application in laundry soap has been decreasing in recent years. Another significant use of rosin soap is as a sizing agent in papermaking, particularly potassium soaps derived from modified rosin (such as adducts with maleic anhydride), which can serve as reinforcing sizing agents. Rosin soap solutions, when blended with other substances, offer additional properties, such as forming metal surface cleaners when mixed with ethylene glycol, acetic acid, water, and ethyl acetate. They can also be used as lubricants and pigment dispersants when combined with ethylene glycol and ethylenediamine.

Sodium rosinate is a hydrophobic surfactant with high surface activity at the solution-air interface, significantly reducing surface tension. When agitating a liquid containing sodium rosinate, it easily incorporates air, forming bubbles with high concentrations. Moreover, due to its good elastic effects, sodium rosinate exhibits good surface rheology and maintains a stable film thickness once a certain concentration is reached. These factors contribute to the high stability of the resulting bubbles.

Sodium rosinate is commonly used in mortar to enhance its fluidity and reduce its bulk density. As an air-entraining agent, sodium rosinate, when introduced in appropriate quantities, creates a large number of discontinuous, minute, and sealed bubbles, which can improve the workability of the mortar to some extent and modify the pore distribution during early freezing. This helps resist the freeze-thaw stress caused by the freezing of unhydrated water, with its mechanism of action primarily reflected in the following aspects:

Under appropriate dosages, sodium rosinate can enhance the pore size distribution of cement-based materials, reducing the porosity to below 20% while decreasing the proportion of harmful large pores and increasing the proportion of beneficial micro-pores that improve early frost resistance, thereby lowering the probable pore size. This is beneficial for the impermeability and durability of cement-based materials.

2. During the early freezing stage, an increased dosage of sodium rosin as an air-entraining agent can lead to reduced strength, which is significantly related to the porosity of the specimen. Moreover, the detrimental effect of the increased harmful pores surpasses the frost-resistant properties of the harmless pores.

Sodium rosinate primarily improves early frost resistance by affecting the pore structure. When fly ash is present along with an accelerator, it can promote the hydration process, but its impact on the hydration of cement and other binding materials is not significant.

In addition, sodium rosinate can be used to prepare a highly stable protective lubricating oil, which is composed of mineral base oil, viscosity index improver, extreme pressure additive, antioxidant, friction reducer, and demulsifier. The viscosity index improver is polyacrylate, the extreme pressure additive is chlorinated paraffin, the antioxidant is glutathione, the friction reducer is sodium rosinate, and the demulsifier is polyoxyethylene alkylamine. This invention boasts high stability, excellent low-temperature fluidity, antioxidant properties, good wear resistance, and superior lubricity.

A mineral slag composite grinding aid for preparation. The composition and quality ratio of the grinding aid are: 5-10% water glass, 5-10% sodium carbonate, 3-8% sodium rosinate, 12-20% betaine mother liquor, 7-12% non-ionic surfactant, 2-10% molasses, 5-10% water-soluble polymer, and the remaining water. The preparation method involves adding water glass, sodium carbonate, betaine mother liquor, and non-ionic surfactant in sequence to water at 40-65°C, stirring until well mixed; then adding sodium rosinate, molasses, and water-soluble polymer, stirring until uniform, resulting in a liquid slag composite grinding aid. This invention reduces production costs and environmental impact, while maintaining stable application performance. It significantly improves the activation and grinding of slag and enhances the physical properties of cement.

A water-soluble pressure-sensitive adhesive is prepared using the following ingredients in parts: 10-15 parts of vinyl acetate-acrylic butyl ester copolymer, 20-25 parts of sodium rosinate, 40-60 parts of vinyl acetate-ethylene copolymer emulsion, 10-20 parts of glycerin, 10-20 parts of ethanol, and 10-15 parts of water. Sodium rosinate is used as the emulsifier, and a blend of vinyl acetate-acrylic butyl ester copolymer and vinyl acetate-ethylene copolymer emulsion is used as the main adhesive component. Assisted by glycerin, ethanol, and water, this method provides a water-soluble pressure-sensitive adhesive with good pressure-sensitive, water-soluble, and dispersible properties.

A new antimicrobial medical plastic packaging bag is prepared using the following weight ratios of raw materials: 50-60 parts of chlorosulfonated polyethylene, 15-25 parts of ethylene vinyl acetate resin, 6-13 parts of polyphosphazene, 3-9 parts of ethylene-octene copolymer, 2-5 parts of sodium rosinate, 1-3 parts of moisture and insect-proof agent, 6-12 parts of oleic acid amide, 2-6 parts of isothiazolinone, 3-8 parts of nano-alumina, 1-3 parts of titanate coupling agent, 8-14 parts of rosin glyceride, 5-11 parts of bamboo fiber, 6-14 parts of silicone oil, 4-8 parts of antimicrobial masterbatch, 2-7 parts of toughening agent, 3-8 parts of xanthan gum, and 1-5 parts of sodium borate. The antimicrobial medical plastic packaging bag of the present invention exhibits excellent antimicrobial properties and is thermodynamically stable.