Method for removing volatile matters in caprolactone polyol

Abstract

The invention provides a method for removing volatile matters in caprolactone polyol. The method comprises the following steps: introducing a caprolactone polyol raw material into short-path distillation equipment for short-path distillation, regulating the main evaporation temperature to 230-260 DEG C and the vacuum degree to 0.01-0.50 mbar, controlling the inner cooling temperature to 30-40 DEG C and the feeding temperature to 100-130 DEG C, and regulating the condensation refrigeration temperature of a first-stage cold trap and a degassing section to-25--15 DEG C; finally, a heavy-phase product treated by the short-path distillation equipment is collected, the acid value of the heavy-phase product is smaller than or equal to 0.10 mgKOH / g, the chromaticity is smaller than or equal to 20 Hazen, and the dispersion coefficient PDI is smaller than or equal to 1.22. Through a short-path distillation technology and under the synergistic effect of a specific main evaporation temperature, an ultrahigh vacuum environment and a feeding amount, the low-temperature limitation of traditional reduced pressure distillation is broken through, volatile matters are efficiently removed, hydroxyl oxidation and molecular cross-linking side reactions are effectively inhibited, and meanwhile, the acid value, the chroma and the PDI value in caprolactone polyol are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high molecular polymerization technology, and particularly to a method for removing volatile components from caprolactone polyol. BACKGROUND

[0002] Caprolactone polyol is a high molecular material with excellent performance, and has a wide range of applications in polyurethane synthesis, coatings, adhesives, and biomedicine due to its good flexibility, weather resistance, and biocompatibility. The molecule structure of caprolactone polyol contains multiple hydroxyl groups, which can react with isocyanate and other compounds to form high molecular polymers with specific properties, thus having high economic value and application prospect in industrial production. However, there are three major problems to be solved in the production of caprolactone polyol.

[0003] First, high acid value: high acid value is the most prominent problem in the production of caprolactone polyol. The acid value mainly comes from the side reactions in the production process, such as the reaction of impurities in the raw materials with the catalyst to generate acidic substances, or the degradation of part of the monomers due to improper control of the reaction conditions during the polymerization reaction, resulting in carboxylic acid compounds. High acid value will have many adverse effects on subsequent processing and application. In the synthesis of polyurethane, high acid value will react with isocyanate, consuming a large amount of isocyanate, increasing the cost of raw materials, and generating carbon dioxide and other gases, resulting in problems such as bubbles in the product, performance degradation, etc. At the same time, acidic substances can also corrode production equipment, shorten the service life of equipment, and increase production costs. In addition, for some application fields sensitive to acid value, such as the biomedicine field, high acid value of caprolactone polyol may affect its biocompatibility, limiting its application in this field. Second, high color value: high color value is also an important problem in the production process of caprolactone polyol. The color value of the product is mainly derived from colored impurities generated during the production process. These impurities may come from insufficient purity of raw materials, such as trace amounts of aldehydes, ketones, and other impurities in caprolactone monomers, which undergo oxidation, condensation, and other reactions during the polymerization reaction, generating colored substances. It may also be due to excessive reaction temperature and reaction time, causing partial oxidation or carbonization of polymer molecules, thus deepening the color of the product. High color value will seriously affect the appearance quality of the product and reduce its market competitiveness in fields such as coatings and adhesives that have high requirements for appearance. Especially in the production of high-grade coatings, caprolactone polyol needs to be colorless or light-colored to ensure uniform and beautiful color of the coating. III. High polydispersity index: A high PDI value is also a key factor restricting the quality of caprolactone polyols. Since PDI is an index for measuring the width of the molecular weight distribution of a polymer, the higher the PDI value, the wider the length distribution of the polymer molecular chain. In the polymerization reaction of caprolactone polyols, due to the uneven conversion rate of monomers, the inconsistent activity of catalysis, and the randomness of chain transfer and chain termination reactions in the reaction process, the molecular weight distribution of the generated polymer is wide, thereby causing the problem of high PDI value. A high PDI value will lead to a decrease in the performance stability of caprolactone polyols. In particular, in the synthesis of polyurethane, caprolactone polyols with wide molecular weight distribution will lead to uneven reaction rates, and the generated polyurethane materials have large differences in performance, with obvious differences in mechanical properties, weather resistance, and other indicators, which cannot guarantee the consistency of product quality. At the same time, the wide distribution of molecular weight will also affect the processing performance of the product, increase the processing difficulty, and reduce the production effect.

[0004] The "three high" problems of high acid value, high color value, and high polydispersity index seriously affect the quality, performance, and application range of the product, leading to the inability to meet the demand of high-end markets for high-quality caprolactone polyols. However, there is currently no related technology that can simultaneously solve the problems of low acid value, low color value, and low PDI value. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a method for removing volatile components from caprolactone polyols, which uses short path distillation, optimizes the temperature and vacuum degree of main evaporation, and optimizes the feeding conditions to solve the problems raised in the above background technology.

[0006] To achieve the above purposes, the present application is implemented by the following technical solutions: According to the first aspect of the present application, a method for removing volatile components from caprolactone polyols is provided. The caprolactone polyol raw material is fed into a short path distillation device for distillation. The main evaporation temperature is controlled to be 230-260℃, the vacuum degree is controlled to be 0.01-0.50mbar, the inner cooling temperature is controlled to be 30-40℃, the feeding temperature is controlled to be 110-130℃, and the condensation refrigeration temperature of the primary cold trap and the degassing section is controlled to be -35--15℃. Finally, the heavy phase product treated by the short path distillation device is collected, and the acid value of the heavy phase product is ≤0.10mgKOH / g, the color value is ≤20Hazen, and the dispersion coefficient PDI is ≤1.22.

[0007] Short path distillation is based on the difference in the mean free path of molecular motion to achieve separation. In a high vacuum environment, the light components (reaction caprolactone monomer, low boiling point by-products and moisture) in the caprolactone polyol have a longer molecular free path and can reach the condensation surface to be captured; while the heavy components (polyol) have a shorter molecular free path and are difficult to reach the condensation surface, achieving devolatilization purification. The caprolactone polyol raw material has a hydroxyl value of 56 mgKOH / g, an acid value of 0.5 mgKOH / g, a moisture content of 80 ppm, a viscosity of 390 mPa·s at 60℃, a color of 10 Hazen, a caprolactone content of 1.019%, a number average molecular weight Mn of 2049, a weight average molecular weight M w The present application uses short path distillation process for devolatilization. Unlike the traditional devolatilization temperature (120~200℃), the low temperature mode is abandoned, and specific vacuum degree and temperature combination are combined to avoid high acid value, high PDI and high color in the product, and to achieve rapid devolatilization of caprolactone polyol, avoiding oxidation or crosslinking of hydroxyl groups. At the same time, the short path distillation equipment occupies a small area, and can reduce energy consumption compared with the traditional low pressure distillation.

[0008] Preferably, the feed amount of the caprolactone polyol raw material into the short path distillation equipment is 8~12 kg / h.

[0009] Further preferably, the feed amount of the caprolactone polyol raw material into the short path distillation equipment is 10 kg / h.

[0010] Preferably, the parameters of the short path distillation are: the main evaporation temperature is 230~260℃, the vacuum degree is 0.01~0.50 mbar, the inner cooling temperature is controlled to 30~40℃, the feed temperature is 110~130℃, and the condensation refrigeration temperature of the first cold trap and the degassing section is adjusted to -25~-15℃.

[0011] Further preferably, the parameters of the short path distillation are: the main evaporation temperature is 250℃, the vacuum degree is 0.01 mbar, the inner cooling temperature is controlled to 35℃, the feed temperature is 120℃, and the condensation refrigeration temperature of the first cold trap and the degassing section is adjusted to -20℃. Beneficial effects

[0012] The present application provides a method for removing volatile components from caprolactone polyol. The method has the following beneficial effects: The method for removing volatile components from caprolactone polyol provided in the present application uses short path distillation technology. Under the synergistic effect of specific main evaporation temperature, ultra-high vacuum environment and feed amount, the low temperature limitation of traditional reduced pressure distillation is broken, and the oxidation of hydroxyl groups and the crosslinking of molecules are effectively inhibited while the volatile components are efficiently removed.

[0013] The method for removing volatile components from caprolactone polyol provided by the scheme can simultaneously reduce acid value, color value and PDI value, the acid value can be reduced to 0.10 mgKOH / g or even below, the color value can be reduced to 20 Hazen or even below, and the PDI value can be reduced to 1.22 or even below, fully meeting the conventional industry standards. DETAILED DESCRIPTION

[0014] The technical scheme of the present application will be further described in detail below in combination with specific examples. It should be understood that the following examples are only exemplary and explanatory of the present application, and should not be interpreted as limiting the scope of protection of the present application. Any technology realized based on the above description of the present application is covered within the scope intended to be protected by the present application.

[0015] Unless otherwise specified, the equipment used in the following examples is commercially available.

[0016] The composition of the selected caprolactone polyol raw material is shown in Table 1: Table 1

[0017] Example 1 The caprolactone polyol raw material was passed into a KD10 full gear pump full insulation type molecular distillation device with a degassing section, the main evaporation temperature was set to 230℃, the vacuum degree was 0.5 mbar, the inner cooling temperature was controlled to 35℃, the feeding temperature was 120℃, the short-range first-stage rotary vane pump was started, and the first-stage cold trap and the degassing section condensing refrigeration temperature was -20℃. After the condition parameters were stable, the caprolactone polyol raw material was passed in at a feeding amount of 10 kg / h, and after a period of stable operation, the heavy phase sample R1 was taken, and the on-site detection showed that the acid value of R1 was 0.10 mgKOH / g, the color value was 15 Hazen, and the PDI value was 1.21.

[0018] Example 2

[0019] The devolatilization method of this example is the same as that of Example 1, the difference is that the vacuum degree is adjusted from 0.5 mbar to 0.05 mbar, after a period of stable operation, the heavy phase sample R2 is taken, and the on-site detection shows that the acid value of R2 is 0.09 mgKOH / g, the color value is 15 Hazen, and the dispersion coefficient PDI is 1.21.

[0020] Example 3

[0021] The devolatilization method of this example is the same as that of Example 1, the difference is that the vacuum degree is adjusted from 0.5 mbar to 0.01 mbar, after a period of stable operation, the heavy phase sample R3 is taken, and the on-site detection shows that the acid value of R3 is 0.09 mgKOH / g, the color value is 15 Hazen, and the dispersion coefficient PDI is 1.20.

[0022] Example 4

[0023] The devolatilization method of this example is the same as that of Example 1, except that the main evaporation temperature is raised from 230°C to 240°C, and the vacuum degree is 0.5 mbar. After stable operation for a period of time, a heavy phase sample R4 is taken, and on-site detection shows that the acid value of R4 is 0.09 mgKOH / g, the colority is 20 Hazen, and the dispersion coefficient PDI is 1.21.

[0024] Example 5

[0025] The devolatilization method of this example is the same as that of Example 4, except that the vacuum degree is adjusted from 0.5 mbar to 0.05 mbar. After stable operation for a period of time, a heavy phase sample R5 is taken, and on-site detection shows that the acid value of R5 is 0.08 mgKOH / g, the colority is 20 Hazen, and the dispersion coefficient PDI is 1.21.

[0026] Example 6

[0027] The devolatilization method of this example is the same as that of Example 4, except that the vacuum degree is adjusted from 0.5 mbar to 0.01 mbar. After stable operation for a period of time, a heavy phase sample R6 is taken, and on-site detection shows that the acid value of R6 is 0.08 mgKOH / g, the colority is 20 Hazen, and the dispersion coefficient PDI is 1.20.

[0028] Example 7

[0029] The devolatilization method of this example is the same as that of Example 1, except that the main evaporation temperature is raised from 230°C to 250°C, and the vacuum degree is 0.5 mbar. After stable operation for a period of time, a heavy phase sample R7 is taken, and on-site detection shows that the acid value of R7 is 0.08 mgKOH / g, the colority is 20 Hazen, and the dispersion coefficient PDI is 1.21.

[0030] Example 8

[0031] The devolatilization method of this example is the same as that of Example 7, except that the vacuum degree is adjusted from 0.5 mbar to 0.05 mbar. After stable operation for a period of time, a heavy phase sample R8 is taken, and on-site detection shows that the acid value of R8 is 0.07 mgKOH / g, the colority is 20 Hazen, and the dispersion coefficient PDI is 1.21.

[0032] Example 9

[0033] The devolatilization method of this example is the same as that of Example 7, except that the vacuum degree is adjusted from 0.5 mbar to 0.01 mbar. After stable operation for a period of time, a heavy phase sample R9 is taken, and on-site detection shows that the acid value of R9 is 0.06 mgKOH / g, the colority is 20 Hazen, and the dispersion coefficient PDI is 1.20.

[0034] Example 10

[0035] The devolatilization method of this example is the same as that of Example 1, except that the main evaporation temperature is raised from 230°C to 260°C, and the vacuum degree is 0.5 mbar. After stable operation for a period of time, a heavy phase sample R10 is taken, and on-site detection shows that the acid value of R10 is 0.08 mgKOH / g, the colority is 20 Hazen, and the dispersion coefficient PDI is 1.22.

[0036] Example 11

[0037] The devolatilization method of this example is the same as that of Example 10, except that the vacuum degree is adjusted from 0.5 mbar to 0.05 mbar. After stable operation for a period of time, a heavy phase sample R11 is taken, and on-site detection shows that the acid value of R11 is 0.07 mgKOH / g, the colority is 20 Hazen, and the dispersion coefficient PDI is 1.21.

[0038] Example 12

[0039] The devolatilization method of this example is the same as that of Example 10, except that the vacuum degree is adjusted from 0.5 mbar to 0.01 mbar. After stable operation for a period of time, a heavy phase sample R12 is taken, and on-site detection shows that the acid value of R12 is 0.06 mgKOH / g, the colority is 20 Hazen, and the dispersion coefficient PDI is 1.20.

[0040] Comparative Example 1 The preparation method of this comparative example is the same as that of Example 1, except that the main evaporation temperature is lowered from 230°C to 180°C, the vacuum degree is 0.5 mbar, and other conditions remain unchanged. After stable operation for a period of time, a heavy phase sample D1 is taken, and on-site detection shows that the acid value of D1 is 0.22 mgKOH / g, the colority is 10 Hazen, and the dispersion coefficient PDI value is 1.19.

[0041] Comparative Example 2 The preparation method of this comparative example is the same as that of Comparative Example 1, except that the vacuum degree is adjusted from 0.5 mbar to 0.05 mbar, and other conditions remain unchanged. After stable operation for a period of time, a heavy phase sample D2 is taken, and on-site detection shows that the acid value of D2 is 0.18 mgKOH / g, the colority is 10 Hazen, and the dispersion coefficient PDI value is 1.18.

[0042] Comparative Example 3 The preparation method of this comparative example is the same as that of Example 1, except that the main evaporation temperature is reduced from 230°C to 200°C, the vacuum degree is 0.5 mbar, and other conditions remain unchanged. After stable operation for a period of time, the heavy phase sample D4 is taken, and the on-site detection of D4 shows an acid value of 0.20 mgKOH / g, a colority of 15 Hazen, and a dispersion coefficient PDI value of 1.20.

[0043] Comparative Example 4 The preparation method of this comparative example is the same as that of Example 1, except that the main evaporation temperature is reduced from 230°C to 200°C, the vacuum degree is 0.5 mbar, and other conditions remain unchanged. After stable operation for a period of time, the heavy phase sample D4 is taken, and the on-site detection of D4 shows an acid value of 0.20 mgKOH / g, a colority of 15 Hazen, and a dispersion coefficient PDI value of 1.20.

[0044] Comparative Example 5 The preparation method of this comparative example is the same as that of Example 1, except that the main evaporation temperature is reduced from 230°C to 200°C, the vacuum degree is 0.5 mbar, and other conditions remain unchanged. After stable operation for a period of time, the heavy phase sample D4 is taken, and the on-site detection of D4 shows an acid value of 0.20 mgKOH / g, a colority of 15 Hazen, and a dispersion coefficient PDI value of 1.20.

[0045] Comparative Example 6 The preparation method of this comparative example is the same as that of Example 1, except that the main evaporation temperature is reduced from 230°C to 200°C, the vacuum degree is 0.5 mbar, and other conditions remain unchanged. After stable operation for a period of time, the heavy phase sample D4 is taken, and the on-site detection of D4 shows an acid value of 0.20 mgKOH / g, a colority of 15 Hazen, and a dispersion coefficient PDI value of 1.20.

[0046] Comparative Example 7 The preparation method of this comparative example is the same as that of Example 1, except that the main evaporation temperature is reduced from 230°C to 200°C, the vacuum degree is 0.5 mbar, and other conditions remain unchanged. After stable operation for a period of time, the heavy phase sample D4 is taken, and the on-site detection of D4 shows an acid value of 0.20 mgKOH / g, a colority of 15 Hazen, and a dispersion coefficient PDI value of 1.20.

[0047] Comparative Example 8 The preparation method of this comparative example is the same as that of Example 1, except that the main evaporation temperature is reduced from 230°C to 200°C, the vacuum degree is 0.5 mbar, and other conditions remain unchanged. After stable operation for a period of time, the heavy phase sample D4 is taken, and the on-site detection of D4 shows an acid value of 0.20 mgKOH / g, a colority of 15 Hazen, and a dispersion coefficient PDI value of 1.20.

[0048] Comparative Example 9 The preparation method of this comparative example is the same as that of Example 2, except that the feed amount is increased from 10 kg / h to 15 kg / h, the main evaporation temperature is 250℃, the vacuum degree is 0.05 mbar, and the other conditions remain unchanged. After stable operation for a period of time, sample D9 of the heavy phase is taken, and the on-site detection shows that the acid value of D9 is 0.12 mgKOH / g, the colority is 20 Hazen, and the dispersion coefficient PDI value is 1.21.

[0049] As can be seen from the comparison of Examples 1 to 12 and Comparative Examples 1 to 9, by adjusting the feed speed and the temperature and vacuum degree of the main evaporation, the acid value, colority and PDI value are simultaneously reduced. When the main evaporation temperature is set to 250℃, the vacuum degree is 0.05 mbar, and the feed amount is 10 kg / h, and combined with the problem of energy saving, the acid value, colority and dispersion coefficient value are comprehensively optimized.

[0050] Comparative Example 10 In this comparative example, falling film devolatilization is used, the falling film main evaporation temperature is set to 180℃, the first-stage rotary vane pump and the Roots pump are turned on, the first-stage cold trap and the degassing section condensing refrigeration temperature are set to -20℃, the vacuum degree is 0.05 mbar, and the feed speed is 10 kg / h. After stable operation for a period of time, sample D10 of the heavy phase is taken, the acid value is 0.22 mgKOH / g, the colority is 40 Hazen, and the dispersion coefficient PDI value is 1.25.

[0051] Comparative Example 11 In this comparative example, falling film devolatilization is used, the falling film main evaporation temperature is set to 200℃, the first-stage rotary vane pump and the Roots pump are turned on, the first-stage cold trap and the degassing section condensing refrigeration temperature are set to -20℃, the vacuum degree is 0.05 mbar, and the feed speed is 10 kg / h. After stable operation for a period of time, sample D11 of the heavy phase is taken, the acid value is 0.20 mgKOH / g, the colority is 60 Hazen, and the dispersion coefficient PDI value is 1.28.

[0052] Comparative Example 12 In this comparative example, falling film devolatilization is used, the falling film main evaporation temperature is set to 270℃, the first-stage rotary vane pump and the Roots pump are turned on, the first-stage cold trap and the degassing section condensing refrigeration temperature are set to -20℃, the vacuum degree is 0.05 mbar, and the feed speed is 10 kg / h. After stable operation for a period of time, sample D12 of the heavy phase is taken, the acid value is 0.12 mgKOH / g, the colority is 100 Hazen, and the dispersion coefficient PDI value is 1.40.

[0053] Comparative Examples 10 to 12 and Example 8 are compared in terms of different devolatilization methods, which show that the traditional falling film devolatilization can only solve one or two of the problems of acid value, colority or PDI, and cannot achieve the simultaneous reduction of the three, and devolatilization has certain limitations.

[0054] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the present application, which is not limited to the exact construction and arrangement described. It is intended, therefore, to cover all modifications and adaptions that fall within the scope of the claims and their equivalents.

Claims

1. A method for removing volatile matter from a caprolactone polyol, characterized by: The caprolactone polyol raw material is fed into a short path distillation device for short path distillation, the main evaporation temperature is controlled to be 230-260 DEG C, the vacuum degree is controlled to be 0.01-0.50 mbar, the inner cooling temperature is controlled to be 30-40 DEG C, the feeding temperature is controlled to be 110-130 DEG C, the first cold trap and the degassing section condensing refrigeration temperature is controlled to be -35--15 DEG C; finally, the heavy phase product after the short path distillation device treatment is collected, the acid value of the heavy phase product is less than or equal to 0.10 mgKOH / g, the colority is less than or equal to 20 Hazen, and the dispersion coefficient PDI is less than or equal to 1.

22.

2. The method of removing volatile matter from a caprolactone polyol according to claim 1, characterized in that: The feeding amount of the caprolactone polyol raw material into the short path distillation device is 8-12 kg / h.

3. The method of removing volatile matter from a caprolactone polyol of claim 1, wherein: The feeding amount of the caprolactone polyol raw material into the short path distillation device is 10 kg / h.

4. The method of removing volatile matter from a caprolactone polyol of claim 1, wherein: The short path distillation device is selected from a full gear pump full insulation type molecular distillation device with a degassing section, and a rotor without a splash plate is selected.

5. The method of removing volatile matter from a caprolactone polyol of claim 1, wherein: The parameters of the short path distillation are as follows: the main evaporation temperature is 230-260 DEG C, the vacuum degree is 0.01-0.50 mbar, the inner cooling temperature is controlled to be 30-40 DEG C, the feeding temperature is controlled to be 110-130 DEG C, and the first cold trap and the degassing section condensing refrigeration temperature is controlled to be -25--15 DEG C.

6. The method of removing volatile matter from a caprolactone polyol of claim 1, wherein: The parameters of the short path distillation are as follows: the main evaporation temperature is 250 DEG C, the vacuum degree is 0.01 mbar, the inner cooling temperature is controlled to be 35 DEG C, the feeding temperature is controlled to be 120 DEG C, and the first cold trap and the degassing section condensing refrigeration temperature is controlled to be -20 DEG C.

Images