阅读说明：本技术 一种降低聚醚多元醇中的醛含量及气味的精制方法 (Refining method for reducing aldehyde content and odor in polyether polyol ) 是由 马爱勤 蔡仲铭 王新宇 朱霞林 徐薇 陈雯慧 于 2020-07-22 设计创作，主要内容包括：本发明涉及一种降低聚醚多元醇中醛含量及气味的精制方法,其包括步骤：1)在25～100℃下,向粗聚醚多元醇中加入占粗聚醚多元醇总质量0.1～10.0％的水,并混合均匀；2)向步骤1的聚醚多元醇中加入占所述粗聚醚多元醇总质量0.1～3％的吸附剂,所述吸附剂为合成硅酸镁和活性炭的混合物,控制吸附温度为80～130℃,吸附平衡之后进行压滤循环,测试压滤后聚醚多元醇中的钾、钠离子含量；3)重复步骤2,直至聚醚多元醇的钾、钠离子含量小于要求的含量；4)向步骤3的聚醚多元醇中加入所需量的抗氧剂；5)升温并真空脱水后,得到精制的聚醚多元醇。本发明所述的方法能够降低醛含量,同时降低气味。(The invention relates to a refining method for reducing aldehyde content and odor in polyether polyol, which comprises the following steps: 1) adding water accounting for 0.1-10.0% of the total mass of the crude polyether polyol into the crude polyether polyol at the temperature of 25-100 ℃, and uniformly mixing; 2) adding an adsorbent accounting for 0.1-3% of the total mass of the crude polyether polyol into the polyether polyol obtained in the step 1, wherein the adsorbent is a mixture of synthetic magnesium silicate and activated carbon, controlling the adsorption temperature to be 80-130 ℃, carrying out filter pressing circulation after adsorption balance, and testing the content of potassium ions and sodium ions in the polyether polyol after filter pressing; 3) repeating the step 2 until the potassium and sodium ion contents of the polyether polyol are less than the required contents; 4) adding a required amount of antioxidant into the polyether polyol obtained in the step 3; 5) heating and vacuum dehydrating to obtain refined polyether polyol. The method of the invention can reduce the aldehyde content and reduce the odor.)

1. A refining method for reducing aldehyde content and odor in polyether polyol comprises the following steps:

1) adding water accounting for 0.1-10.0 percent of the total mass of the crude polyether polyol, preferably 2.0-8.0 percent of the total mass of the crude polyether polyol into the crude polyether polyol at the temperature of 25-100 ℃, and stirring to uniformly mix the water and the crude polyether polyol;

2) adding an adsorbent which accounts for 0.1-3%, preferably 0.2-1.5% of the total mass of the crude polyether polyol into the polyether polyol obtained in the step 1), wherein the adsorbent is a mixture of synthetic magnesium silicate and activated carbon, the adsorption temperature is controlled to be 80-130 ℃, preferably 80-100 ℃, adsorption is carried out under stirring, filter pressing circulation is carried out after adsorption balance, and the contents of potassium ions and sodium ions in the polyether polyol after filter pressing are tested by sampling;

3) if the content of potassium ions and sodium ions in the polyether polyol obtained in the step 2) is larger than the content of potassium ions and sodium ions required by the finished product polyether polyol, repeating the step 2) until the content of potassium ions and sodium ions in the polyether polyol is smaller than or equal to the content of potassium ions and sodium ions in the finished product polyether polyol;

4) adding an antioxidant accounting for 0.03 to 0.4 percent of the total mass of the crude polyether polyol into the polyether polyol obtained in the step 3);

5) heating and vacuum dehydrating to obtain refined polyether polyol.

2. The refining method of claim 1, wherein in step 1), the added water is deionized water.

3. The refining method according to claim 1 or 2, wherein the mass ratio of the synthetic magnesium silicate and the activated carbon in the adsorbent in step 2) is 1 to 5: 1, preferably 2 to 4: 1.

4. the refining method according to any one of claims 1 to 3, wherein,

the particle size of the synthetic magnesium silicate is 10-60 mu m, and the molar ratio of silicon element to magnesium element is 2.7-3.4: 1, the content of the synthetic magnesium silicate is more than or equal to 75 wt%;

the particle size of the active carbon is 20-60 mm, and the iodine adsorption value is 600-900 mg/g.

5. The refining method according to any one of claims 1 to 4, wherein in step 3), the number of times step 2) is repeatedly performed is 1 to 2 times.

6. The refining method according to any one of claims 1 to 5, wherein the antioxidant is a hindered phenol, a hindered amine, a phosphite ester, or a complex antioxidant; preferably a hindered phenol, more preferably pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ].

7. The refining method of any one of claims 1 to 6, wherein, in step 5), the pressure of the vacuum dehydration step is controlled to be ≦ -0.09MPa, and the temperature is controlled to be in the range of 115 to 125 ℃.

8. The refining process as defined in any one of claims 1 to 7, wherein, in the refined polyether polyol obtained in step 5), the sodium ion content is 5ppm or less, preferably 3ppm or less; the content of potassium ions is less than or equal to 5ppm, preferably less than or equal to 3 ppm; the formaldehyde content is less than or equal to 2ppm, preferably less than or equal to 1 ppm; the acetaldehyde content is less than or equal to 2ppm, preferably less than or equal to 1 ppm; acrolein content of less than or equal to 2ppm, preferably acrolein content of less than or equal to 1 ppm; and a propanal content of 10ppm or less, preferably a propanal content of 5ppm or less.

9. The purification process according to any one of claims 1 to 8, wherein the crude polyether polyol is produced using an alkali metal compound as a catalyst, the alkali metal compound is selected from potassium oxide, sodium oxide, potassium hydroxide, sodium hydroxide, potassium alkoxide, or sodium alkoxide, the polyether polyol has a functionality of 2 to 8, and a number average molecular weight of 200 to 16000.

10. A polyether polyol obtained according to the refining process of any one of claims 1 to 9, preferably having a sodium ion content of 5ppm or less, more preferably having a sodium ion content of 3ppm or less; the content of potassium ions is less than or equal to 5ppm, preferably less than or equal to 3 ppm; the formaldehyde content is less than or equal to 2ppm, preferably less than or equal to 1 ppm; the acetaldehyde content is less than or equal to 2ppm, preferably less than or equal to 1 ppm; acrolein content of less than or equal to 2ppm, preferably acrolein content of less than or equal to 1 ppm; and a propanal content of 10ppm or less, preferably a propanal content of 5ppm or less.

Technical Field

The invention relates to the technical field of polyether polyol preparation, in particular to a refining method for reducing aldehyde content and odor in polyether polyol.

Background

Polyether polyol is one of the main raw materials for synthesizing polyurethane resin, and is widely applied to the fields of polyurethane foam plastics, polyurethane coatings, polyurethane adhesives, polyurethane elastomers and the like. At present, along with the improvement of living standard of people, people put forward higher and higher requirements on environmental protection and body health. At present, the odor problem of polyether polyol is still outstanding, the odor of polyether polyol mainly comes from aldehydes such as formaldehyde, acetaldehyde, acrolein and the like, although the content of the aldehydes in the polyether polyol is generally low, the odor of polyether polyol is greatly influenced by the aldehydes, and at present, various polyether manufacturers search for an effective method for removing the aldehyde content and the odor in polyether polyol.

Various methods have therefore been developed in the art to reduce or remove these aldehydes from polyether polyols. For example, chinese application publication CN 108059717 a, discloses that the VOC content of polyether polyol is reduced by adding a formulated antioxidant to the crude polyether polyol during the pre-treatment stage (water addition stage of conventional phosphoric acid neutralization refining process) to inhibit the generation of aldehydes during the post-treatment stage. However, the method has the disadvantages that the antioxidant is added in the early stage, and more antioxidant is consumed in the post-treatment stage, so that the content of the antioxidant in the final product is reduced, the yellowing resistance and the burning resistance of the polyether polyol during the later application are influenced, in addition, the content of VOC in the final product prepared by the method is still high, and the effect of removing VOC in the polyether polyol by the method is not obvious.

The Chinese application publication CN 106832249A introduces a refining method for reducing the odor of high-activity polyether polyol without adding acid, and the method comprises the steps of adding neutralizing water, adding a refined adsorbent A under the condition of nitrogen for stirring, adding a refined adsorbent B, stirring for a period of time, dehydrating, drying and filtering to obtain the low-odor high-activity polyether polyol. The method needs two adsorbents, and has more steps; moreover, the method is carried out under the nitrogen condition, and the operation requirement is higher; but also has effect only aiming at the high-activity polyether polyol and cannot be applied in the field of polyether polyol preparation on a large scale.

Disclosure of Invention

Based on the defects of the prior art, the invention aims to solve the problems of high content of polyether polyol aldehyde and large smell in the prior art. Accordingly, it is an object of the present invention to provide a purification process for reducing the aldehyde content and odor of polyether polyol, which process can effectively control the potassium ion and sodium ion content of polyether polyol and can significantly reduce the odor of the obtained polyether polyol.

According to a first aspect of the present invention, there is provided a purification process for reducing the aldehyde content and odor of a polyether polyol, the process comprising the steps of:

1) adding water accounting for 0.1-10.0 percent of the total mass of the crude polyether polyol, preferably 2-8 percent of the total mass of the crude polyether polyol into the crude polyether polyol at the temperature of 25-100 ℃, and stirring to uniformly mix the water and the crude polyether polyol;

2) adding an adsorbent which accounts for 0.1-3%, preferably 0.2-2% and more preferably 0.2-1.5% of the total mass of the crude polyether polyol into the polyether polyol obtained in the step 1), wherein the adsorbent is a mixture of synthetic magnesium silicate and activated carbon, the adsorption temperature is controlled to be 80-130 ℃, preferably 80-100 ℃, adsorption is carried out under stirring, filter pressing circulation is carried out after adsorption balance, and the contents of potassium ions and sodium ions in the polyether polyol after filter pressing are tested by sampling;

3) if the content of potassium ions and sodium ions in the polyether polyol obtained in the step 2) is larger than the content of potassium ions and sodium ions required by the finished product polyether polyol, repeating the step 2) until the content of potassium ions and sodium ions in the polyether polyol is smaller than or equal to the content of potassium ions and sodium ions in the finished product polyether polyol;

4) adding an antioxidant accounting for 0.03 to 0.4 percent of the total mass of the crude polyether polyol into the polyether polyol obtained in the step 3);

5) heating and vacuum dehydrating to obtain refined polyether polyol.

Preferably, in step 1), after the addition of water, sufficient stirring is carried out to thoroughly mix the water with the crude polyether polyol, for example, stirring for 30 to 120 minutes, preferably 30 to 60 minutes.

Preferably, the water added in step 1) is deionized water.

Preferably, in step 2), the adsorption is carried out under stirring, for example for 30 to 180 minutes, preferably 60 to 120 minutes.

Preferably, the mass ratio of the synthetic magnesium silicate to the activated carbon in the adsorbent in the step 2) is 1-5: 1, preferably 2 to 4: 1. the particle size of the synthetic magnesium silicate is 10-60 mu m, wherein the molar ratio of silicon element to magnesium element is 2.7-3.4: 1, the content of the synthetic magnesium silicate is more than or equal to 75wt percent. Preferred particle sizes of the activated carbon: 20-60 mm, and an iodine adsorption value of 600-900 mg/g.

Preferably, in the step 3), the step 2) is repeatedly carried out for 1-2 times, and if the content of potassium ions and sodium ions in the polyether polyol measured after the first adsorption and pressure filtration is higher than the requirement of the finished polyether polyol product, the operation of the step 2 is repeatedly carried out; if the content of potassium ions and sodium ions measured after the first adsorption and pressure filtration is lower than the requirement of the finished polyether polyol product, the operation of the step 2 is not required to be repeated;

in the step 4), the antioxidant is selected from hindered phenol, hindered amine, phosphite ester or composite antioxidant; hindered phenols are preferred, and pentaerythrityl tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] (abbreviated as antioxidant 1010) is more preferred.

Preferably, in the step 5), the pressure in the vacuum dehydration step is controlled to be less than or equal to-0.09 MPa, and the temperature is controlled to be within the range of 115-125 ℃.

Preferably, in the refined polyether polyol obtained in step 5), the sodium ion content is less than or equal to 5ppm, preferably less than or equal to 3 ppm; the content of potassium ions is less than or equal to 5ppm, preferably less than or equal to 3 ppm; the formaldehyde content is less than or equal to 2ppm, preferably less than or equal to 1ppm, more preferably less than or equal to 0.5 ppm; acetaldehyde content of 2ppm or less, preferably acetaldehyde content of 1ppm or less, more preferably acetaldehyde content of 0.6ppm or less; acrolein content of less than or equal to 2ppm, preferably acrolein content of less than or equal to 1ppm, more preferably acrolein content of less than or equal to 0.2 ppm; and a propanal content of 10ppm or less, preferably a propanal content of 5ppm or less, more preferably a propanal content of 3ppm or less.

Preferably, the crude polyether polyol is prepared by taking an alkali metal compound as a catalyst, wherein the alkali metal compound is selected from potassium oxide, sodium oxide, potassium hydroxide, sodium hydroxide, potassium alkoxide or sodium alkoxide, the functionality of the polyether polyol is 2-8, and the number average molecular weight is 200-16000.

According to a second aspect of the present invention, there is provided a polyether polyol obtained by the refining method.

Wherein, in the polyether polyol, the content of sodium ions is less than or equal to 5ppm, preferably the content of sodium ions is less than or equal to 3 ppm; the content of potassium ions is less than or equal to 5ppm, preferably less than or equal to 3 ppm; the formaldehyde content is less than or equal to 2ppm, preferably less than or equal to 1ppm, more preferably less than or equal to 0.5 ppm; acetaldehyde content of 2ppm or less, preferably acetaldehyde content of 1ppm or less, more preferably acetaldehyde content of 0.6ppm or less; acrolein content of less than or equal to 2ppm, preferably acrolein content of less than or equal to 1ppm, more preferably acrolein content of less than or equal to 0.2 ppm; and a propanal content of 10ppm or less, preferably a propanal content of 5ppm or less, more preferably a propanal content of 3ppm or less.

The invention has the beneficial effects that:

1. according to the invention, through the combined application of the synthesized magnesium silicate and the activated carbon adsorbent, alkali metal ions (mainly potassium ions and sodium ions) in polyether polyol can be effectively removed through 1-2 times of adsorption, and meanwhile, the synthesized magnesium silicate and the activated carbon adsorbent can effectively adsorb aldehydes and other impurities in the polyether polyol, so that the aldehyde content of the polyether polyol is reduced, and the quality of the polyether polyol is ensured.

The refining process of the invention adopts less adsorbent, reduces the generation amount of solid waste in the polyether polyol synthesis process, namely, the residual amount of polyether polyol in the solid waste can be reduced, the yield of polyether polyol is improved, and the cost is saved.

Detailed Description

The following examples further illustrate the present invention, but the scope of the present invention is not limited to the following examples.

In the examples of the present invention and comparative examples, the following crude polyether polyols were used, which are products of Wanhua chemical group, Inc.

Polyether polyol 1: prepared by ring-opening polymerization of glycerin as an initiator and propylene oxide, and has a hydroxyl value of 560mgKOH/g, a molecular weight of 300 and a KOH content of 0.15 wt%;

polyether polyol 2: is prepared by ring-opening polymerization of propylene glycol as an initiator and propylene oxide, and has a hydroxyl value of 160mgKOH/g, a molecular weight of 700 and a KOH content of 0.25 wt%;

polyether polyol 3: is prepared by ring-opening polymerization of propylene glycol as an initiator and propylene oxide, and has a hydroxyl value of 56mgKOH/g, a molecular weight of 2000 and a KOH content of 3.0 wt%;

polyether polyol 4: is prepared by ring-opening polymerization of pentaerythritol as an initiator, propylene oxide and ethylene oxide, and has a hydroxyl value of 56mgKOH/g, a molecular weight of 4000 and a KOH content of 3.0 wt%;

polyether polyol 5: is prepared by ring-opening polymerization of glycerin as an initiator, propylene oxide and ethylene oxide, and has a hydroxyl value of 28mgKOH/g, a molecular weight of 6000 and a KOH content of 3.2 wt%;

polyether polyol 6: is prepared by ring-opening polymerization of sorbitol as an initiator, propylene oxide and ethylene oxide, and has a hydroxyl value of 28mgKOH/g, a molecular weight of 12000 and a KOH content of 3.5 wt%;

other main raw material sources

The synthetic magnesium silicate is selected from Dallas (Qingdao) Special adsorbent, Inc.

The activated carbon is selected from activated carbon of Shandong Nanke.

Test method in the invention

Determination standards for potassium and sodium ions in polyether polyols: GB/T12008.4-2009 (GB/T12008.4-2009),

determination of moisture in polyether polyols: GB/T12008.4-1989.

Determination standard of VOC content in polyether polyol: GB/T37196-2018.