The effects on the utilization of rosin by some of the major guidelines

      1.Color: Color is one major indicator of rosin's quality class. It is an essential factor of rosin quality.

      2.Softening point: Rosin has a softening point lower than that of each resin acid constituting it because it is not a simple mixture of these resin acids, but it contains high-boiling pointed sesquiterpenes and other neural substances. The lower the softening point, the lower the quality.
Users usually want the softening point to be high so as to advance their product quality and make technique innovations.
      To make modified rosin is just to heighten the softening point. Therefore, it is required that raw rosin used to produce modified rosin have a softening point of about 80 ℃.
Softening point is partially related to oil percentage of rosin. Generally speaking, the higher the oil contents, the lower the softening point, although the relationship is not proportional.

      3. Acid value: The number of potassium hydroxide in the measure of milligram to neutralize 1 gram of rosin is called acid value. It indicates the content of organic acid in the rosin. The mason pine rosin generally has an acid value of 145-170mgKOH/g. Rosin with high acid value can be esterified into high ester valued esters, and is used specially in certain adhesive.

      4. Unsaponifieable substance: content that does not react with alkali in rosin is called unsaponifieable substance.  In papermaking industry, rosin with high unsopanifieable content will lead to the misproportion of the emultion, thus harming the evenness of sizing and decreasing paper quality.
Rosin with high unsopanifieable content makes the ink viscous, not easily dried. In the producing of neoprene, the product will stick to the roller if unsopanifieable content is high.  In soap industry, it is expected that unsopanifieable content be below 2%. High unsopanifieable content will make the soap viscous, and it has foam-reducing effect that decreases the decontamination ability of the soap.

      5. Physical impurity: Contents that cannot be dissolved into alcohol are physical impurities of rosin.
Physical impurity has bad effects on the surfaces of products such as paper, paint and synthetic rubber. Therefore, physical impurities must be of low content.

      6. Crystallization: After crystallization, rosin has a high melting point of up to 110-130℃. This is harmful to the utilization of it. It can make paper stained, or make paint surface coarse in paint industry. In addition, it is also not suitable for the producing of hard resin and chemicals with flux. Therefore, both the producers and the consumers of rosin pay much attention to the problem of crystallization of rosin.

      Guidelines for the quality of turpentine include color, specific weight, refraction index, volume of distillate below 170℃ and acid value, etc. In some countries, optical rotation and distillation residue are also included.
      1. Appearance and Color: Pure turpentine should be colorless and transparent. If water is not cleared in the producing process or the packing vessel is rust, it turned yellow and turbid. Hence, before production completes, water should be removed as clearly as possible.
      2. Specific Weight: Specific weight depends on the different kind of terpene hydrocarbon it contains. Bicycloterpene hydrocarbon has the largest specific weight, and then Monocyclo-terpene; Open chain hydrocarbon has the least specific weight.
      3. Refraction index: Refraction Index is an indicator of substance property. It is the ratio of light velocity in two media. With the same acid value, the higher the refraction index, the more content of high-boiling pointed distillations in the turpentine.
      4. Volume of Distillate below 170℃: This is a major indicator of turpentine quality. Since α-pinene has a boiling point of 155-156℃, β-pinene 162-163℃, and 170-185℃ for most bicycloterpenes, 254-256℃ for longifolene, the more the volume of distillation below 170℃, the higher percentage of valuable contents such as α-pinene and β-pinene.
      5. Acid Value: Turpentine is a neural mixture of terpene. In the producing of it, if rosin foam is taken into the condenser, or if rosin is boiled off under a high temperature, the output turpentine will be weakly acidic. High acid valued turpentine can erode the tin containing it, thus making itself look yellow. Such turpentine need another distillation before using. Therefore, the acid value of turpentine should be as low as possible.
      6. Optical Rotation: When a linearly polarized light beam passes through a liquid containing asymmetric carbon atoms or optically active substances, an optical rotation will occur, namely, the polarization plane of the light will rotate right or left. Such rotations has certain degrees of rotation, this is called degree of optical rotation. Even the same kind of terpene from different places has different property of optical rotation. For instance, the α-pinene in the turpentine of China, Portugal and France has a sinistral optical rotation, while that of Soviet Russia, Greece and India is dextral.   Different species of trees produce turpentine with different optical rotation. That of mason and slash pine is sinistral, and that of longleaf pine is dextral.
      7. Distillation Residue: These are mostly resin acid and other neural substances with high boiling point in the turpentine. Residue content should be as low as possible.