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CN-121974922-A - Sorbitol diacetal nucleating agent and preparation method thereof

CN121974922ACN 121974922 ACN121974922 ACN 121974922ACN-121974922-A

Abstract

The invention relates to a sorbitol diacetal nucleating agent and a preparation method thereof, wherein the nucleating agent is 1,3:2, 4-di (3, 4-dimethylbenzylidene) sorbitol, sorbitol and 3, 4-dimethylbenzylidene are used as raw materials, aldol condensation is carried out under the action of an acid catalyst, and after the reaction is completed, ammonia methanol solution is used for quenching to prepare the 1,3:2, 4-di (3, 4-dimethylbenzylidene) sorbitol. The nucleating agent has a melting point of more than 273 ℃, and is free from adding a yellowing agent when being applied to polyolefin, and has a low yellow index.

Inventors

  • LI RUI
  • WANG ZI
  • ZHAO QIANG
  • ZHANG JI
  • YANG LEI
  • LIU BINBIN

Assignees

  • 利安隆（中卫）新材料有限公司
  • 天津利安隆新材料股份有限公司
  • 利安隆（珠海）新材料有限公司

Dates

Publication Date
20260505
Application Date
20260114
Priority Date
20250829

Claims (10)

  1. 1. The preparation method of the sorbitol diacetal nucleating agent is characterized in that the nucleating agent is 1,3:2, 4-di (3, 4-dimethylbenzylidene) sorbitol, the method takes sorbitol and 3, 4-dimethylbenzylidene as raw materials, aldol condensation is carried out under the action of an acid catalyst, and after the reaction is completed, ammonia methanol solution is used for quenching reaction, so that 1,3:2, 4-di (3, 4-dimethylbenzylidene) sorbitol is obtained.
  2. 2. The preparation method of claim 1, wherein the ratio of the ammonia methanol solution to the sorbitol is 0.5-1:1 by volume, and preferably the ammonia content of the ammonia methanol solution is 5-20% by weight.
  3. 3. The preparation method of claim 1, wherein the reaction is performed in a mixed solvent, the mixed solvent is a mixed solvent comprising a nonpolar solvent and a polar solvent, preferably the nonpolar solvent is one or more of n-hexane, cyclohexane, toluene and xylene, the polar solvent is one or more of methanol, ethanol and isopropanol, and/or the weight ratio of sorbitol to 3, 4-dimethylbenzaldehyde is 20-30:27-40.
  4. 4. The preparation method of claim 1, wherein the acid catalyst is selected from one or more of benzenesulfonic acid, p-toluenesulfonic acid and 4-n-dodecylbenzenesulfonic acid, and preferably the weight ratio of the acid catalyst to sorbitol is 0.2-1:20-30.
  5. 5. The method according to claim 3, wherein the quenching is completed and further comprises a refining step of dispersing the crude product in an ammonia methanol solution or an ammonia aqueous methanol solution, stirring, filtering and drying to obtain a pure 1,3:2, 4-bis (3, 4-dimethylbenzylidene) sorbitol product.
  6. 6. The preparation method according to claim 5, wherein the ratio (v/w) of the methanol solution of ammonia to the sorbitol is 10-20:1 by volume, and preferably the ammonia content in the ammonia methanol solution is 5-20%.
  7. 7. The method according to any one of claims 1 to 6, wherein the prepared nucleating agent 1,3:2, 4-bis (3, 4-dimethylbenzylidene) sorbitol has a melting point of 273 ℃ or more.
  8. 8. A sorbitol diacetal nucleating agent is 1,3:2, 4-di (3, 4-dimethylbenzylidene) sorbitol, the melting point of the nucleating agent is above 273 ℃, preferably, the initial melting point of the sorbitol diacetal nucleating agent is 273.0-274.0 ℃, and the final melting point of the sorbitol diacetal nucleating agent is 274.0-275.5 ℃.
  9. 9. A composition comprising a polyolefin and 1,3:2, 4-bis (3, 4-dimethylbenzylidene) sorbitol prepared by the method of any one of claims 1 to 7 or 1,3:2, 4-bis (3, 4-dimethylbenzylidene) sorbitol of claim 8, preferably the polyolefin comprises Polyethylene (PE), polypropylene (PP), polybutene (PB), polyisobutene (PIB).
  10. 10. The preparation method of the composition according to claim 1-7, the sorbitol diacetal nucleating agent according to claim 8 and the application of the composition according to claim 9 in polyolefin products.

Description

Sorbitol diacetal nucleating agent and preparation method thereof Technical Field The invention relates to the field of material auxiliaries, in particular to a high-performance transparent nucleating agent 1,3:2, 4-di (3, 4-dimethylbenzylidene) sorbitol and a preparation method thereof. Background Polyolefin polymers such as polyethylene and polypropylene have the advantages of light weight, low cost, no toxicity, no smell, easy processing and the like, and are widely applied. The sorbitol acetal polypropylene transparent nucleating agent can improve the transparency and comprehensive mechanical properties of common polypropylene. The third generation sorbitol acetal polypropylene transparent nucleating agent has particularly outstanding performance, and is represented by sorbitol and 3, 4-dimethylbenzaldehyde condensate (CAS: 135861-56-2, chemical name: 1,3:2, 4-di (3, 4-dimethylbenzylidene) sorbitol, trade mark 3988) so that the odor and odor migration of the PP transparent packaging product are extremely small, the PP transparent packaging product can be safely used as a transparent packaging material, and is very suitable for food packaging and packaging sensitive to odor. CN1511160a discloses a preparation method of condensing in water by using inorganic acid as catalyst and adding surfactant, but a large amount of powder is formed in the later period of the reaction, and the powder cannot be stirred, the yield is only 65% -80%, and the utilization ratio of raw materials is low. CN101434607a discloses a preparation method of a product obtained by catalyzing p-toluenesulfonic acid, using cyclohexane and methanol as solvents, performing ternary azeotropic dehydration, then quenching reaction, refluxing cyclohexane/isopropanol for 1 hour, then filtering, and refining with acetone, wherein the yield is lower than 80%, and the melting point is lower than 260 ℃. The condensation products of sorbitol and 3, 4-dimethylbenzaldehyde disclosed in the prior art are low in yield and low in melting point. Disclosure of Invention For the technical problems in the background technology, the invention provides the preparation method of the 1,3:2, 4-di (3, 4-dimethylbenzylidene) sorbitol, and the prepared product has high melting point and can have good yellowing inhibiting effect in polyolefin without adding a yellowing agent. The first aspect of the invention provides a preparation method of a sorbitol diacetal nucleating agent, wherein the sorbitol diacetal nucleating agent is1, 3:2, 4-di (3, 4-dimethylbenzylidene) sorbitol, the method takes sorbitol and 3, 4-dimethylbenzylidene as raw materials, aldol condensation is carried out under the action of an acid catalyst, and after the reaction is completed, ammonia methanol solution is used for quenching reaction, so that 1,3:2, 4-di (3, 4-dimethylbenzylidene) sorbitol is obtained. Through intensive researches, the fact that the melting point of the nucleating agent is related to the preparation process of the product is found, when the product is in a gel state after the reaction is completed, partial catalyst can be wrapped at the stage, the partial catalyst is difficult to remove in subsequent processes such as refining or purifying, the residue of the acid catalyst has a certain influence on the performance of the product, and particularly, the melting point of the product is low. The application discovers that the acid catalyst can be effectively removed when the ammonia methanol solution is used as the quenching agent, acidic substances in the prepared product are reduced to the minimum, and the melting point of the product can reach more than 273 ℃. In a specific embodiment, ammonia methanol solution is used for quenching reaction, and the ratio of the parts by volume and weight (v/w, ml/g) of the ammonia methanol solution to the sorbitol is 0.5-1:1. For example 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1. The ammonia methanol can be fully contacted with the residual catalyst and can be fully removed. The residual acid catalyst can be removed with maximum efficiency by controlling the amount of ammonia methanol within the above range. In a specific embodiment, the ammonia content of the ammonia methanol solution is 5% -20% (i.e. the concentration of ammonia in methanol) by weight, which has a better effect. Preferably, the ammonia content of the ammonia methanol solution is 5% -15% by weight. In a specific embodiment, the reaction is carried out in a mixed solvent comprising a mixed solvent of a nonpolar solvent and a polar solvent. Preferably, the nonpolar solvent is one or more of n-hexane, cyclohexane, toluene and xylene, and the polar solvent is one or more of methanol, ethanol and isopropanol. For example, the mixed solvents of the reaction are cyclohexane and methanol, cyclohexane and ethanol. The mixed solvent in the reaction system can form a ternary azeotropic system with water, so that the water is taken out of the reaction mixture, which is beneficial to fo