阅读说明：本技术 一种聚酯多元醇及其制备方法和应用 (Polyester polyol and preparation method and application thereof ) 是由 徐耀维 肖丽群 朱彦 杜宗波 汪忠敏 唐劲松 于 2020-12-22 设计创作，主要内容包括：本发明提供一种聚酯多元醇及其制备方法和应用,所述聚酯多元醇的制备原料按照重量百分比计,包括如下组分：二甘醇20～55％、除二甘醇以外的二元醇0～25％、脂肪族二元酸45～65％、稳定剂0.001～0.1％和催化剂0.002～0.02％。本发明通过添加稳定剂来限制聚酯多元醇制备过程1,4-二氧六环副产物的产生,可以将1,4-二氧六环的生成量限制在小于7克/千克二甘醇,优选小于4克/千克二甘醇,亦可以将1,4-二氧六环的量限制在小于3克/千克聚酯多元醇,优选小于2克/千克聚酯多元醇。本发明的聚酯多元醇可以应用于涂料等通用型聚氨酯制品中。(The invention provides polyester polyol and a preparation method and application thereof, wherein the preparation raw materials of the polyester polyol comprise the following components in percentage by weight: 20-55% of diethylene glycol, 0-25% of dihydric alcohol except diethylene glycol, 45-65% of aliphatic dibasic acid, 0.001-0.1% of stabilizer and 0.002-0.02% of catalyst. The invention limits the generation of 1, 4-dioxane by-product in the preparation process of polyester polyol by adding a stabilizer, can limit the generation amount of 1, 4-dioxane to less than 7 g/kg of diethylene glycol, preferably less than 4 g/kg of diethylene glycol, and also can limit the amount of 1, 4-dioxane to less than 3 g/kg of polyester polyol, preferably less than 2 g/kg of polyester polyol. The polyester polyol can be applied to general polyurethane products such as coatings.)

1. The polyester polyol is characterized in that the preparation raw materials of the polyester polyol comprise the following components in percentage by weight:

2. the polyester polyol according to claim 1, wherein the dihydric alcohol other than diethylene glycol comprises any one of ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 2-methyl-1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol, or 1, 6-hexanediol, or a combination of at least two thereof.

3. The polyester polyol according to claim 1 or 2, wherein the aliphatic dibasic acid comprises any one of succinic acid, glutaric acid, adipic acid, azelaic acid or sebacic acid or a combination of at least two thereof.

4. The polyester polyol according to any one of claims 1 to 3, wherein the stabilizer comprises a phosphate-based heat stabilizer and a phosphite-based heat oxygen stabilizer;

preferably, the phosphate-based heat stabilizer comprises any one of triphenyl phosphate, triethyl methylphosphonate or triethyl phosphonoacetate;

preferably, the phosphite thermal oxygen stabilizer includes any one of triphenyl phosphite, tris (2, 4-di-t-butylphenyl) phosphite, bis (2, 4-di-t-butylphenyl) pentaerythritol diphosphite, dioctadecyl pentaerythritol diphosphite or tetrakis (2, 4-di-t-butylphenol) -4,4' -biphenylyl diphosphite.

5. The polyester polyol according to any one of claims 1 to 4, wherein the catalyst comprises any one of tetraisopropyl titanate, tetra-n-butyl titanate, tetra-t-butyl titanate, or stannous octoate.

6. Process for the preparation of the polyester polyol according to any of claims 1 to 5, characterized in that it comprises the following steps:

(1) uniformly stirring diethylene glycol, dihydric alcohol except diethylene glycol, aliphatic dibasic acid and a stabilizer, heating for reaction, then heating at a constant speed, and carrying out esterification dehydration reaction;

(2) and (2) adding a catalyst into the reaction liquid obtained in the step (1), preserving heat, and then carrying out reduced pressure distillation for polycondensation reaction to obtain the polyester polyol.

7. The preparation method according to claim 6, wherein the temperature rise reaction in the step (1) is to rise to 130-160 ℃;

preferably, the reaction time of the temperature-rising reaction in the step (1) is 30-120 min;

preferably, the constant temperature rise in the step (1) is to rise to 210-250 ℃ at a rate of 5-30 ℃/h;

preferably, the esterification and dehydration reaction time in the step (1) is 3-5 h.

8. The preparation method according to claim 6 or 7, wherein the temperature of the heat preservation in the step (2) is 210-250 ℃;

preferably, the heat preservation time in the step (2) is 30-180 min;

preferably, the pressure of the reduced pressure distillation in the step (2) is-78 to-100 kPa;

preferably, the time of the polycondensation reaction in the step (2) is 2-6 h.

9. The production method according to any one of claims 6 to 8, wherein the hydroxyl value of the polyester polyol of step (2) is 30 to 120mg KOH/g;

preferably, the acid value of the polyester polyol in the step (2) is 0.1-1.0 mg KOH/g.

10. Use of a polyester polyol according to any of claims 1 to 5 in a general purpose polyurethane article.

Technical Field

The invention belongs to the technical field of preparation of aliphatic polyester polyol, relates to polyester polyol and a preparation method and application thereof, and particularly relates to polyester polyol with low 1, 4-dioxane byproduct and a preparation method and application thereof.

Background

Polyester polyols, especially aliphatic polyester polyols, are intermediates for many polyurethane adhesives, coatings, elastomers. In the preparation of aliphatic polyester polyols, such as polyester polyols prepared from adipic acid and diethylene glycol, 1, 4-dioxane is produced as a by-product during the reaction. In the production process in a factory, 1, 4-dioxane produced as a distillate is discharged together with the esterification water and then must be decomposed or concentrated incinerated, for example, in sewage treatment, and this additionally introduced process step leads to an increase in the cost of producing the polyester polyol.

CN102203154A discloses a process for preparing polyester polyols from at least one carboxylic anhydride and diethylene glycol, which suppresses the formation of 1, 4-dioxane to a large extent from diethylene glycol by means of special reaction control, it being possible to limit the amount of 1, 4-dioxane to less than 5 g/kg of diethylene glycol. However, the amount of 1, 4-dioxane produced is still further reduced.

CN102803329A discloses a process for the preparation of polyester polyols from at least one aromatic dicarboxylic acid or aromatic dicarboxylic acid alkyl ester or aromatic dicarboxylic anhydride and at least one α, ω -diol, which invention greatly suppresses the formation of 1, 4-dioxane from diethylene glycol by a specific reaction treatment, it being possible to limit the amount of 1, 4-dioxane to less than 10 g/kg of diethylene glycol used. However, the amount of 1, 4-dioxane produced is still further reduced.

Accordingly, it is desirable in the art to develop a polyester polyol having low 1, 4-dioxane by-product.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide polyester polyol and a preparation method and application thereof. The polyester polyol can generate less 1, 4-dioxane by-products in the preparation process, and can be applied to general polyurethane products such as coatings and the like.

In order to achieve the purpose, the invention adopts the following technical scheme:

on one hand, the invention provides polyester polyol, which comprises the following components in percentage by weight:

in the present invention, the addition of the stabilizer can reduce the amount of the by-product of 1, 4-dioxane generated by the dehydration of diethylene glycol itself in the esterification stage, and can reduce the amount of the by-product of 1, 4-dioxane generated by the degradation of polymer chains caused by the catalyst in the polycondensation stage, thereby reducing the amount of the by-product of 1, 4-dioxane generated from diethylene glycol.

In the present invention, diethylene glycol may be used in an amount of 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, or the like, in the raw materials for preparing the polyester polyol.

In the present invention, the amount of the dihydric alcohol other than diethylene glycol used in the raw materials for preparing the polyester polyol may be 0%, 5%, 10%, 15%, 20%, 25%, or the like.

In the present invention, the amount of the aliphatic dibasic acid used in the raw materials for preparing the polyester polyol may be 45%, 50%, 55%, 60%, 65%, or the like.

In the present invention, the amount of the stabilizer used in the raw material for producing the polyester polyol may be 0.001%, 0.005%, 0.01%, 0.05%, 0.08%, 0.1%, or the like.

In the present invention, the amount of the catalyst used in the raw materials for producing the polyester polyol may be 0.002%, 0.005%, 0.008%, 0.01%, 0.015%, 0.02%, or the like.

In the present invention, the dihydric alcohol other than diethylene glycol includes any one of ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 2-methyl-1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol, or 1, 6-hexanediol, or a combination of at least two thereof. Combinations of the at least two, for example, ethylene glycol and 1, 2-propylene glycol, 1, 3-propylene glycol and 2-methyl-1, 3-propylene glycol, 1, 4-butylene glycol and 1, 5-pentanediol, and neopentyl glycol, and the like.

In the present invention, the aliphatic dibasic acid includes any one of succinic acid, glutaric acid, adipic acid, azelaic acid or sebacic acid or a combination of at least two thereof. Combinations of the at least two, such as succinic and glutaric acids, adipic and azelaic acids, and sebacic acids, and the like.

In the invention, the stabilizer comprises a phosphate-based heat stabilizer and a phosphite-based heat oxygen stabilizer, and the combination of the two stabilizers can better reduce the generation of 1, 4-dioxane by-products.

Preferably, the phosphate-based heat stabilizer comprises any one of triphenyl phosphate, triethyl methylphosphonate or triethyl phosphonoacetate.

Preferably, the phosphite thermal oxygen stabilizer includes any one of triphenyl phosphite, tris (2, 4-di-t-butylphenyl) phosphite, bis (2, 4-di-t-butylphenyl) pentaerythritol diphosphite, dioctadecyl pentaerythritol diphosphite or tetrakis (2, 4-di-t-butylphenol) -4,4' -biphenylyl diphosphite.

In the present invention, the catalyst includes any one of tetraisopropyl titanate, tetra-n-butyl titanate, tetra-t-butyl titanate, or stannous octoate.

In another aspect, the present invention provides a method for preparing the polyester polyol as described above, comprising the steps of:

(1) uniformly stirring diethylene glycol, dihydric alcohol except diethylene glycol, aliphatic dibasic acid and a stabilizer, heating for reaction, then heating in a gradient manner, and carrying out esterification dehydration reaction;

(2) and (2) adding a catalyst into the reaction liquid obtained in the step (1), preserving heat, and then carrying out reduced pressure distillation for polycondensation reaction to obtain the polyester polyol.

The preparation method of the polyester polyol is carried out under the protection of inert gas (such as nitrogen and the like).

In the invention, the temperature rise reaction in the step (1) is to rise to 130-160 ℃, such as 130 ℃, 133 ℃, 145 ℃, 158 ℃ or 160 ℃ and the like.

Preferably, the reaction time of the temperature-raising reaction in the step (1) is 30-120 min, such as 30min, 40min, 60min, 80min, 100min or 120 min.

Preferably, the constant temperature rise in the step (1) is to rise to 210-250 ℃, for example, 210 ℃, 223 ℃, 235 ℃, 248 ℃ or 250 ℃ at a rate of 5-30 ℃/h (for example, 5 ℃/h, 10 ℃/h, 15 ℃/h, 20 ℃/h, 25 ℃/h or 30 ℃/h, etc.). The invention adopts a mode of uniform temperature rise to improve the yield of the polyester diol.

Preferably, the esterification and dehydration reaction time in the step (1) is 3-5 h, such as 3h, 3.5h, 4h, 4.5h or 5 h.

In the invention, the temperature of the heat preservation in the step (2) is 210-250 ℃, such as 210 ℃, 223 ℃, 235 ℃, 248 ℃ or 250 ℃ and the like.

Preferably, the time for the heat preservation in the step (2) is 30-180 min, such as 30min, 60min, 90min, 120min, 160min or 180 min.

Preferably, the pressure of the reduced pressure distillation in the step (2) is-78 to-100 kPa, such as-78 kPa, -80kPa, -85kPa, -98kPa or-100 kPa.

Preferably, the time of the polycondensation reaction in the step (2) is 2-6 h, such as 2h, 2.5h, 3h, 4h, 5h or 6 h.

In the invention, the hydroxyl value of the polyester polyol in the step (2) is 30-120 mg KOH/g, such as 30mg KOH/g, 60mg KOH/g, 90mg KOH/g or 120mg KOH/g.

Preferably, the acid value of the polyester polyol in the step (2) is 0.1-1.0 mg KOH/g, such as 0.1mg KOH/g, 0.5mg KOH/g, 0.8mg KOH/g, or 1.0mg KOH/g.

In a further aspect, the present invention provides the use of a polyester polyol as described above in general purpose polyurethane articles such as coatings.

Compared with the prior art, the invention has at least the following beneficial effects:

the invention limits the generation of 1, 4-dioxane byproduct in the preparation process of polyester polyol by adding a stabilizer (preferably a combination of a phosphate-based heat stabilizer and a phosphite-based heat oxygen stabilizer), and the addition of the stabilizer can reduce the amount of 1, 4-dioxane generated by self-dehydration of diethylene glycol in an esterification stage and reduce the amount of 1, 4-dioxane generated by degradation of a polymer chain caused by a catalyst in a polycondensation stage, thereby reducing the generation of the 1, 4-dioxane byproduct. In this way, the formation of 1, 4-dioxane can be limited to less than 7 g/kg of diethylene glycol, preferably less than 4 g/kg of diethylene glycol, and the formation of 1, 4-dioxane can also be limited to less than 3 g/kg of polyester polyol, preferably less than 2 g/kg of polyester polyol.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

Example 1

In this embodiment, a polyester polyol is provided, and a raw material for preparing the polyester polyol comprises the following components in percentage by weight:

the preparation method comprises the following steps:

(1) under the protection of nitrogen, adding diethylene glycol, adipic acid, triethyl phosphonoacetate and triphenyl phosphite into a 500mL four-neck reaction flask (which is provided with a heating jacket, a magnetic stirrer, a temperature probe, a customized distillation head, a condensation reflux device and a receiving bottle cooled by a salt-ice bath), uniformly stirring, heating to 140 ℃ for reaction for 60min, then uniformly heating to 220 ℃ at a constant speed of 20 ℃/h, and carrying out esterification dehydration reaction for 4 h;

(2) adding tetraisopropyl titanate into the reaction liquid obtained in the step (1), preserving the heat at 220 ℃ for 60min, and then carrying out reduced pressure distillation (the pressure is-98 kPa) to carry out polycondensation reaction for 6h to obtain the polyester polyol.

Wherein during the reaction, the distillate was collected in a receiver flask, and then the amount of the formed 1, 4-dioxane by-product was measured with a gas chromatograph (Shimadzu, GC-2010 Plus).

Example 2

In this embodiment, a polyester polyol is provided, and a raw material for preparing the polyester polyol comprises the following components in percentage by weight:

the preparation method comprises the following steps:

(1) under the protection of nitrogen, adding diethylene glycol, ethylene glycol, adipic acid, triethyl methylphosphonate and tris (2, 4-di-tert-butylphenyl) phosphite into a 500mL four-mouth reaction flask (which is provided with a heating jacket, a magnetic stirrer, a temperature probe, a customized distillation head, a condensation reflux device and a receiving bottle cooled by an ice salt bath), uniformly stirring, heating to 130 ℃ for reaction for 30min, then heating to 230 ℃ at a constant speed at a speed of 30 ℃/h, and carrying out esterification dehydration reaction for 3 h;

(2) adding tetraisopropyl titanate into the reaction liquid obtained in the step (1), preserving the heat at 230 ℃ for 90min, and then carrying out polycondensation reaction by reduced pressure distillation (the pressure is-78 kPa), wherein the reaction time is 4h, so as to obtain the polyester polyol.

Wherein during the reaction, the distillate was collected in a receiver flask, and then the amount of the formed 1, 4-dioxane by-product was measured with a gas chromatograph (Shimadzu, GC-2010 Plus).

Example 3

In this embodiment, a polyester polyol is provided, and a raw material for preparing the polyester polyol comprises the following components in percentage by weight:

the preparation method comprises the following steps:

(1) under the protection of nitrogen, adding diethylene glycol, ethylene glycol, succinic acid, triethyl phosphonoacetate and dioctadecyl pentaerythritol diphosphite into a 500mL four-neck reaction flask (which is provided with a heating jacket, a magnetic stirrer, a temperature probe, a customized distillation head, a condensation reflux device and a receiving bottle cooled by a salt-ice bath), uniformly stirring, heating to 150 ℃ for reaction for 120min, then heating to 210 ℃ at a constant speed at a speed of 5 ℃/h, and carrying out esterification dehydration reaction for 5 h;

(2) adding tetra-n-butyl titanate into the reaction liquid in the step (1), preserving heat for 180min at 210 ℃, and then carrying out polycondensation reaction by reduced pressure distillation (the pressure is-100 kPa), wherein the reaction time is 2h, so as to obtain the polyester polyol.

Wherein during the reaction, the distillate was collected in a receiver flask, and then the amount of the formed 1, 4-dioxane by-product was measured with a gas chromatograph (Shimadzu, GC-2010 Plus).

Example 4

In this embodiment, a polyester polyol is provided, and a raw material for preparing the polyester polyol comprises the following components in percentage by weight:

the preparation method comprises the following steps:

(1) under the protection of nitrogen, adding diethylene glycol, 1, 4-butanediol, adipic acid, succinic acid, triphenyl phosphate and triphenyl phosphite into a 500mL four-mouth reaction flask (which is provided with a heating jacket, a magnetic stirrer, a temperature probe, a customized distillation head, a condensation reflux device and a receiving bottle cooled by an ice salt bath), uniformly stirring, heating to 160 ℃ for reaction for 90min, then heating to 250 ℃ at a constant speed at a speed of 20 ℃/h, and carrying out esterification dehydration reaction for 4.5 h;

(2) and (2) adding tetrabutyl titanate into the reaction liquid obtained in the step (1), preserving the heat at 240 ℃ for 30min, and then carrying out reduced pressure distillation (the pressure is-80 kPa) to carry out polycondensation reaction for 3h to obtain the polyester polyol.

Wherein during the reaction, the distillate was collected in a receiver flask, and then the amount of the formed 1, 4-dioxane by-product was measured with a gas chromatograph (Shimadzu, GC-2010 Plus).

Example 5

In this embodiment, a polyester polyol is provided, and a raw material for preparing the polyester polyol comprises the following components in percentage by weight:

the preparation method comprises the following steps:

(1) under the protection of nitrogen, adding diethylene glycol, ethylene glycol, 1, 4-butanediol, adipic acid, azelaic acid, triethyl phosphate and bis (2, 4-di-tert-butylphenyl) pentaerythritol diphosphite into a 500mL four-neck reaction flask (which is provided with a heating jacket, a magnetic stirrer, a temperature probe, a customized distillation head, a condensation reflux device and a receiving bottle cooled by a salt-ice bath), uniformly stirring, heating to 145 ℃ for reaction for 80min, then heating to 240 ℃ at a constant speed of 10 ℃/h, and carrying out esterification dehydration reaction for 3.5 h;

(2) adding stannous octoate into the reaction liquid obtained in the step (1), preserving the heat at 250 ℃ for 100min, and then carrying out polycondensation reaction by reduced pressure distillation (the pressure is-90 kPa), wherein the reaction time is 5h, so as to obtain the polyester polyol.

Wherein during the reaction, the distillate was collected in a receiver flask, and then the amount of the formed 1, 4-dioxane by-product was measured with a gas chromatograph (Shimadzu, GC-2010 Plus).

Comparative example 1

This comparative example differs from example 1 only in that the heat stabilizer triethylphosphonoacetate was not included in the starting materials for the preparation.

Comparative example 2

This comparative example differs from example 1 only in that the thermal oxygen stabilizer triphenyl phosphite is not included in the starting materials for the preparation.

The polyester polyols of examples 1-5 and comparative examples 1-2 were tested for their performance by the following methods:

1. measurement of acid value

(1) Accurately weighing 6-12 g of sample in a 250mL conical flask;

(2) measuring 30mL of toluene-methanol solution in the conical flask, plugging a plug, and performing ultrasonic treatment until the toluene-methanol solution is completely dissolved;

(3) adding 2-3 drops of phenolphthalein indicator, titrating with a calibrated 0.1mol/L potassium hydroxide-ethanol solution until the solution becomes reddish, and keeping the reddish color for 30s to obtain a titration end point;

(4) adding no sample into a 250mL conical flask, adding only 30mL of toluene-methanol solution, and repeating the step (3) to carry out a blank test;

(5) the calculation formula of Acid Value (AV) is as follows: AV ═ V (V-V)₀)*C*M/m

In the formula: v-the amount of the potassium hydroxide-ethanol solution used for titrating the sample, mL;

V₀-amount of potassium hydroxide-ethanol solution in the blank test, mL;

c- -concentration of potassium hydroxide-ethanol solution, mol/L;

m- -molar mass of potassium hydroxide, g/mol;

m represents the weight of the sample, g.

2. Determination of hydroxyl number

(1) Accurately weighing 3-6 g of sample, and placing the sample in a 250mL conical flask;

(2) accurately transferring 5mL of acetylation reagent into the conical flask by using a pipette, plugging a plug, performing ultrasonic treatment until the acetylation reagent is completely dissolved, and standing for 5min to ensure that the acetylation reagent is completely reacted;

(3) adding 2mL of distilled water into the conical flask, shaking up, transferring 10mL of pyridine-water solution, slowly adding into the conical flask for washing the flask wall, shaking up, and standing for 5 min;

(4) adding 8-9 drops of phenolphthalein indicator, titrating with a calibrated 0.6mol/L potassium hydroxide-ethanol solution until the solution becomes reddish, and keeping the reddish color for 30s to obtain a titration end point;

(5) adding no sample into a 250mL conical flask, and repeating the steps (2), (3) and (4) to carry out blank tests;

(6) the hydroxyl value (OH value, OHV) is calculated as follows: OHV ═ V₀-V)*C*M/m

In the formula: v₀-amount of potassium hydroxide-ethanol solution in the blank test, mL;

v-the amount of the potassium hydroxide-ethanol solution used for titrating the sample, mL;

c- -concentration of potassium hydroxide-ethanol solution, mol/L;

m- -molar mass of potassium hydroxide, g/mol;

m represents the weight of the sample, g.

The results of the performance tests are shown in table 1.

TABLE 1

As can be seen from Table 1, the amount of 1, 4-dioxane produced is less in examples 1-5 (3.3-7.1 g/kg diethylene glycol, 1.3-2.0 g/kg polyester polyol) than in comparative examples 1 and 2, which shows that the introduction of the specific combination of thermal stabilizer and thermal oxygen stabilizer of the present invention can reduce the production of 1, 4-dioxane as a by-product.

The applicant states that the present invention is illustrated by the above examples of the polyester polyol of the present invention and the preparation method thereof, but the present invention is not limited to the above examples, i.e., it does not mean that the present invention must be implemented by relying on the above examples. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.