Preparation method of low-viscosity polyester polyol

Abstract

The invention relates to the technical field of polyester polyol, in particular to a preparation method of low-viscosity polyester polyol, which comprises the following steps: compounding linear polyester polyol, rigid branched polyester polyol and flexible branched polyester polyol according to a specific ratio, and introducing the branched polyester polyol into the polyester polyol, thereby obtaining the low-viscosity polyester polyol. Wherein the rigid branched polyester polyol can effectively improve the thermal stability of the polyester polyol and has a better plasticizing effect, the flexible branched polyester polyol effectively makes up the defects of high material viscosity and reduced fluidity caused by too high crosslinking degree and branching degree of the rigid branched polyester polyol, and meanwhile, the linear polyester polyol is compounded, so that the mechanical properties of the rigid branched polyester polyol and the flexible branched polyester polyol are greatly improved. According to the preparation method, the problems of brittleness increase and high processing difficulty caused by overhigh material rigidity are avoided, and the finally obtained polyester polyol has relatively high fluidity and relatively low viscosity and has a wide application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of polyester polyols, and in particular to a method for preparing low-viscosity polyester polyols. Background Art

[0002] Plasticizer is a substance mainly used in elastomer systems, plastics, resins and other materials. It can improve the processing performance and plasticity of the above materials and reduce the glass transition temperature of the materials. Plasticizers can be divided into internal and external plasticizers. The molecules of external plasticizers are not connected to the molecules of polymers through valence bonds, so there are problems of migration, evaporation and extraction loss. Its plasticization mechanism is divided into two types: non-polar and polar. The non-polar mechanism of external plasticizers is isolation, which reduces the force between polymer molecules and plays a plasticizing role.

[0003] Common polyester plasticizers are polyester polyols, which are usually formed by polycondensation and transesterification of organic dicarboxylic acids (anhydrides or esters) with polyols or by polymerization of lactones with polyols. They are generally low molecular weight, amorphous, and branched polymers that can be crosslinked later. The main chain contains an ester group (-COO-). In addition to the ester group, the polyester polyol material usually has hydroxyl, carboxyl and other groups. However, existing polyester polyols used as plasticizers generally have the problem of high viscosity. For example, the patent technical document CN111995742A uses titanate as a catalyst, firstly vegetable oil and triol are transesterified to obtain an intermediate product, and then esterification is carried out with dibasic acids, diols, etc. to prepare nitrogen-containing heterocyclic polyester polyols. In addition, some polyester polyols with lower viscosity will have the problem of poor speed-increasing effect and poor solvent extraction resistance.

[0004] Therefore, according to the above-mentioned related technologies, it is urgent to develop a method for preparing low-viscosity polyester polyols. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a method for preparing a low-viscosity polyester polyol to solve the problem in the prior art that it is difficult for polyester polyol to have both low viscosity and good plasticizing effect.

[0006] Based on the above purpose, the present invention provides a method for preparing low-viscosity polyester polyol.

[0007] A method for preparing a low-viscosity polyester polyol comprises the following steps:

[0008] The polyester A, polyester B and polyester C are mixed to obtain a low-viscosity polyester polyol;

[0009] The polyester A is a linear polyester polyol;

[0010] The polyester B is a rigid branched polyester polyol;

[0011] The polyester C is a flexible branched polyester polyol;

[0012] The linear polyester polyol is obtained by mixing a linear component 1 and a linear component 2;

[0013] The linear component 1 and the linear component 2 are both prepared from 1,4-butanediol, ethylene glycol and adipic acid;

[0014] The rigid branched polyester polyol is obtained by mixing a phthalic anhydride sulfonic acid type polyester polyol and a phosphorus heterocyclic type polyester polyol;

[0015] The phosphorus heterocyclic polyester polyol contains a biphenyl ring and a phenanthrene ring;

[0016] The flexible branched polyester polyol is obtained by mixing a sulfonic acid type polyester polyol and a phthalic anhydride type polyester polyol.

[0017] Preferably, the preparation process of the linear component 1 is as follows:

[0018] Put 1,4-butanediol and ethylene glycol into a reaction bottle, then add adipic acid, raise the temperature to 225-230°C, keep the temperature for reaction for 50-60 minutes, add tetrabutyl titanate and reduce the pressure to -1-0.8mPa, react for 50-60 minutes, and when the hydroxyl value is 34-40mgKOH / g, cool and discharge the material to obtain linear component 1;

[0019] The usage ratio of 1,4-butanediol, ethylene glycol, adipic acid and tetrabutyl titanate is 2-2.2 mol: 1-1.05 mol: 1-1.4 mol: 0.0388-0.0468 g.

[0020] Preferably, the preparation process of the linear component 2 is as follows:

[0021] Step A1. Add ethylene glycol and adipic acid into a reaction flask, heat to 180-200°C, and keep the temperature for 4-4.5 hours to obtain a mixture A;

[0022] Step A2. Add adipic acid and 1,4-butanediol into a reaction flask, raise the temperature to 180-200°C, and keep the temperature for 4-4.5 hours to obtain a mixture B;

[0023] Step A3. Add mixture A and mixture B into a reaction bottle, heat to 240-245°C, keep warm for 50-60 minutes, add tetrabutyl titanate and reduce the pressure to -1-0.8 mPa, react for 50-60 minutes, and when the hydroxyl value is 34-40 mgKOH / g, cool and discharge to obtain linear component 2.

[0024] Preferably, the molar ratio of ethylene glycol to adipic acid in step A1 is 1-1.05:2-2.05;

[0025] The molar ratio of adipic acid to 1,4-butanediol in step A2 is 1-1.05:2.05-2.2;

[0026] In step A3, the usage ratio of mixed material A, mixed material B and tetrabutyl titanate is 1-1.05 mol:1.5-1.8 mol:0.0362-0.0422 g.

[0027] Preferably, the preparation process of the phthalic anhydride sulfonic acid type polyester polyol is as follows:

[0028] Mix dimethyl isophthalate-5-sulfonic sodium salt, 1,6-hexanediol and monobutyltin oxide under nitrogen atmosphere, heat to 190-200°C and keep warm for 50-60 minutes, then cool to 80-85°C, add phthalic anhydride, heat to 215-220°C and keep warm for 100-120 minutes, add xylene, and when the acid value drops to 1-3 mgKOH / g, cool to 75-80°C and discharge to obtain phthalic anhydride sulfonic acid type polyester polyol;

[0029] The usage ratio of dimethyl isophthalate-5-sodium sulfonate, 1,6-hexanediol, monobutyltin oxide, phthalic anhydride and xylene is 0.0559-0.0578g: 1-1.03mol: 0.0224-0.0232g: 1.09-1.13mol: 6.99-7.23g.

[0030] Preferably, the preparation process of the phosphorus heterocyclic polyester polyol is as follows:

[0031] Mix DOPO and diethylene glycol, add maleic acid when the temperature rises to 75-80°C, react at 75-80°C for 5.5-6h, add ethylene glycol and adipic acid respectively, heat to 145-150°C, add cycerol, and then heat to 215-220°C until the acid value drops to 2mgKOH / g, discharge the material, and obtain phosphorus heterocyclic polyester polyol;

[0032] The molar ratio of DOPO, diethylene glycol, maleic acid, ethylene glycol, adipic acid and sec is 0.6-0.7:1-1.2:0.7-0.75:1-1.2:1-1.06:0.2-0.26.

[0033] Preferably, the preparation process of the sulfonic acid type polyester polyol is as follows:

[0034] Mix dimethyl isophthalate-5-sulfonic sodium salt, 1,6-hexanediol and monobutyltin oxide under nitrogen atmosphere, heat to 190-200°C and keep warm for 50-60 minutes, then cool to 80-85°C, add hexanediol, heat to 215-220°C and keep warm for 100-120 minutes, add xylene, and when the acid value drops to 1-3 mgKOH / g, cool to 75-80°C and discharge to obtain phthalic anhydride sulfonic acid type polyester polyol;

[0035] The usage ratio of dimethyl isophthalate-5-sodium sulfonate, 1,6-hexanediol, monobutyltin oxide, hexanediol and xylene is 0.0559-0.0578g: 1-1.03mol: 0.0224-0.0232g: 1.09-1.13mol: 6.99-7.23g.

[0036] Preferably, the preparation process of the phthalic anhydride type polyester polyol is as follows:

[0037] Mix 1,6-hexanediol and monobutyltin oxide under nitrogen atmosphere, heat to 190-200°C and keep warm for 50-60 minutes, then cool to 80-85°C, add phthalic anhydride, heat to 215-220°C and keep warm for 100-120 minutes, add xylene, and when the acid value drops to 1-3 mgKOH / g, cool to 75-80°C and discharge to obtain phthalic anhydride sulfonic acid type polyester polyol;

[0038] The usage ratio of the 1,6-hexanediol, monobutyltin oxide, phthalic anhydride and xylene is 1-1.03 mol: 0.0224-0.0232 g: 1.09-1.13 mol: 6.99-7.23 g.

[0039] Preferably, the mass ratio of polyester A, polyester B and polyester C is 2-2.8:1.5-2:0.5-0.8.

[0040] Preferably, the mass ratio of linear component 1 to linear component 2 in the linear polyester polyol is 1.4-1.8:0.6-1;

[0041] The mass ratio of the phthalic anhydride sulfonic acid polyester polyol to the phosphorus heterocyclic polyester polyol in the rigid branched polyester polyol is 1-1.2:0.5-0.8;

[0042] The mass ratio of the sulfonic acid type polyester polyol to the phthalic anhydride type polyester polyol in the flexible branched polyester polyol is 0.2-0.4:0.3-0.4.

[0043] Beneficial effects of the present invention:

[0044] The invention provides a method for preparing a low-viscosity polyester polyol. The invention compounds a linear polyester polyol, a rigidly branched polyester polyol and a flexible branched polyester polyol to prepare a polyester polyol having strong fluidity and low viscosity and good plasticizing effect. The material plasticized by the polyester polyol prepared by the invention also has high thermal stability.

[0045] The invention provides a method for preparing a low-viscosity polyester polyol. The invention introduces branched polyester polyols into polyester polyols, wherein the rigid branched polyester polyols can effectively improve the thermal stability of the polyester polyols, and the flexible branched polyester polyols effectively make up for the defects of the rigid branched polyols, such as high material viscosity and reduced fluidity, caused by excessive crosslinking and branching degree. At the same time, linear polyester polyols are compounded to avoid the problems of increased brittleness and great processing difficulty caused by excessive rigidity of the materials. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0047] Embodiment 1: A method for preparing a low-viscosity polyester polyol comprises the following steps:

[0048] S1. 2 mol of 1,4-butanediol and 1 mol of ethylene glycol were put into a reaction bottle, and then 1 mol of adipic acid was added, and the temperature was raised to 225°C, and the temperature was kept for reaction for 50 minutes, and 0.0388 g of tetrabutyl titanate was added to reduce the pressure to -1 mPa, and the reaction was carried out for 50 minutes. When the hydroxyl value was 34 mgKOH / g, the temperature was lowered and the material was discharged to obtain a linear component 1;

[0049] S2. 1 mol of ethylene glycol and 2 mol of adipic acid were added to a reaction flask, the temperature was raised to 180°C, and the reaction was kept at this temperature for 4 hours to obtain a mixture A;

[0050] S3. 1 mol of adipic acid and 2.05 mol of 1,4-butanediol were added to a reaction flask, the temperature was raised to 180°C, and the reaction was kept at this temperature for 4 hours to obtain a mixture B;

[0051] S4. 1 mol of mixed material A and 1.5 mol of mixed material B were put into a reaction flask, heated to 240°C, kept warm for 50 min, 0.0362 g of tetrabutyl titanate was added and the pressure was reduced to -1 mPa, and the reaction was continued for 50 min. When the hydroxyl value was 34 mgKOH / g, the temperature was lowered and the material was discharged to obtain a linear component 2;

[0052] S5. 1.4 g of the linear component 1 and 0.6 g of the linear component 2 are mixed to obtain a linear polyester polyol, namely, polyester A;

[0053] S6. 0.0559 g of sodium dimethyl isophthalate-5-sulfonate, 1 mol of 1,6-hexanediol and 0.0224 g of monobutyltin oxide were mixed under a nitrogen atmosphere, heated to 190°C for 50 min, then cooled to 80°C, 1.09 mol of phthalic anhydride was added, heated to 215°C for 100 min, 6.99 g of xylene was added, and when the acid value dropped to 1 mgKOH / g, the temperature was lowered to 75°C to obtain a phthalic anhydride sulfonic acid type polyester polyol;

[0054] S7. 0.6 mol DOPO and 1 mol diethylene glycol were mixed, 0.7 mol maleic acid was added when the temperature was raised to 75°C, and after reacting at 75°C for 5.5 hours, 1 mol ethylene glycol and 1 mol adipic acid were added respectively, the temperature was raised to 145°C, 0.2 mol succinate was added, and the temperature was raised to 215°C until the acid value dropped to 2 mgKOH / g, and the material was discharged to obtain a phosphorus heterocyclic polyester polyol;

[0055] S8. 1-1.05-1.1-1.15-1.2g of phthalic anhydride sulfonic acid type polyester polyol and 0.5-0.6-0.7-0.8-0.75g of phosphorus heterocyclic polyester polyol are mixed to obtain a rigid branched polyester polyol, that is, polyester B is obtained;

[0056] S9. 0.0559 g of sodium 5-sulfonate dimethyl isophthalate, 1 mol of 1,6-hexanediol and 0.0224 g of monobutyltin oxide were mixed under a nitrogen atmosphere, heated to 190°C for 50 min, then cooled to 80°C, 1.09 mol of hexanediol was added, heated to 215°C for 100 min, 6.99 g of xylene was added, and when the acid value dropped to 1 mgKOH / g, the temperature was lowered to 75°C to obtain a phthalic anhydride sulfonic acid type polyester polyol;

[0057] S10. 1 mol of 1,6-hexanediol and 0.0224 g of monobutyltin oxide were mixed under a nitrogen atmosphere, heated to 190°C for 50 min, then cooled to 80°C, 1.09 mol of phthalic anhydride was added, heated to 215°C for 100 min, 6.99 g of xylene was added, and when the acid value dropped to 1 mgKOH / g, the temperature was lowered to 75°C to obtain a phthalic anhydride sulfonic acid type polyester polyol;

[0058] S11. 0.2 g of sulfonic acid type polyester polyol and 0.3 g of phthalic anhydride type polyester polyol were mixed to obtain a flexible branched polyester polyol, namely, polyester C;

[0059] S12. Mix 2 g of polyester A, 1.5 g of polyester B and 0.5 g of polyester C to obtain a low-viscosity polyester polyol.

[0060] Embodiment 2: A method for preparing a low-viscosity polyester polyol comprises the following steps:

[0061] S1. 2.05 mol 1,4-butanediol and 1.01 mol ethylene glycol were added to a reaction bottle, and then 1.1 mol adipic acid was added, the temperature was raised to 226°C, and the reaction was kept at this temperature for 52 minutes. 0.0401 g tetrabutyl titanate was added and the pressure was reduced to -0.95 mPa, and the reaction was continued for 52 minutes. When the hydroxyl value was 36 mg KOH / g, the temperature was lowered and the material was discharged to obtain a linear component 1;

[0062] S2. Add 1-1.02-1.03-1.04-1.05 mol of ethylene glycol and 2-2.02-2.03-2.04-2.05 mol of adipic acid into a reaction flask, raise the temperature to 180-185-190-195-200° C., and keep the temperature for 4-4.2-4.3-4.4-4.5 hours to obtain a mixture A;

[0063] S3. 1.02 mol of adipic acid and 2.1 mol of 1,4-butanediol were added to a reaction flask, the temperature was raised to 185° C., and the reaction was kept at this temperature for 4.2 h to obtain a mixture B;

[0064] S4. 1.02 mol of mixed material A and 1.6 mol of mixed material B were put into a reaction flask, heated to 242°C, kept warm for 52 min, 0.0381 g of tetrabutyl titanate was added and the pressure was reduced to -0.95 mPa, reacted for 52 min, and when the hydroxyl value was 36 mgKOH / g, the temperature was lowered and the material was discharged to obtain a linear component 2;

[0065] S5. 1.5 g of the linear component 1 and 0.7 g of the linear component 2 are mixed to obtain a linear polyester polyol, namely, polyester A;

[0066] S6. 0.0563 g of sodium dimethyl isophthalate-5-sulfonate, 1.01 mol of 1,6-hexanediol and 0.0228 g of monobutyltin oxide were mixed under a nitrogen atmosphere, heated to 192 ° C for 52 min, then cooled to 82 ° C, 1.1 mol of phthalic anhydride was added, heated to 216 ° C for 105 min, 7.02 g of xylene was added, and when the acid value dropped to 1.5 mgKOH / g, the temperature was lowered to 76 ° C to obtain a phthalic anhydride sulfonic acid type polyester polyol;

[0067] S7. 0.63 mol DOPO and 1.05 mol diethylene glycol were mixed, 0.72 mol maleic acid was added when the temperature was raised to 76°C, and after reacting at 76°C for 5.7 hours, 1.05 mol ethylene glycol and 1.02 mol adipic acid were added respectively, the temperature was raised to 147°C, 0.22 mol succinate was added, and the temperature was raised to 217°C until the acid value dropped to 2 mgKOH / g, and the material was discharged to obtain a phosphorus heterocyclic polyester polyol;

[0068] S8. 1.05 g of sulfonic acid-based polyester polyol and 0.6 g of phosphorus heterocyclic polyester polyol were mixed to obtain a rigid branched polyester polyol, namely, polyester B;

[0069] S9. 0.0562 g of sodium dimethyl isophthalate-5-sulfonate, 1.01 mol of 1,6-hexanediol and 0.0228 g of monobutyltin oxide were mixed under a nitrogen atmosphere, heated to 192 ° C for 52 min, then cooled to 82 ° C, 1.1 mol of hexanediol was added, the temperature was raised to 217 ° C for 105 min, 7.11 g of xylene was added, and the acid value was reduced to 1.5 mgKOH / g. The temperature was lowered to 77 ° C to obtain a phthalic anhydride sulfonic acid type polyester polyol;

[0070] S10. 1.01 mol 1,6-hexanediol and 0.0226 g monobutyltin oxide were mixed under a nitrogen atmosphere, heated to 192°C for 52 min, then cooled to 82°C, 1.1 mol phthalic anhydride was added, heated to 217°C for 105 min, 7.02 g xylene was added, and when the acid value dropped to 1.5 mg KOH / g, the temperature was lowered to 77°C to obtain a phthalic anhydride sulfonic acid type polyester polyol;

[0071] S11. 0.25 g of sulfonic acid type polyester polyol and 0.33 g of phthalic anhydride type polyester polyol were mixed to obtain a flexible branched polyester polyol, namely, polyester C;

[0072] S12. 2.2 g of polyester A, 1.7 g of polyester B and 0.6 g of polyester C are mixed evenly to obtain a low-viscosity polyester polyol.

[0073] Embodiment 3: A method for preparing a low-viscosity polyester polyol comprises the following steps:

[0074] S1. 2.1 mol 1,4-butanediol and 1.02 mol ethylene glycol were added to a reaction bottle, and then 1.2 mol adipic acid was added, the temperature was raised to 227°C, and the reaction was kept at this temperature for 54 minutes. 0.0423 g tetrabutyl titanate was added and the pressure was reduced to -0.9 mPa, and the reaction was continued for 54 minutes. When the hydroxyl value was 38 mg KOH / g, the temperature was lowered and the material was discharged to obtain a linear component 1;

[0075] S2. 1.03 mol of ethylene glycol and 2.03 mol of adipic acid were added to a reaction flask, the temperature was raised to 190° C., and the reaction was kept at this temperature for 4.3 h to obtain a mixture A;

[0076] S3. 1.03 mol of adipic acid and 2.15 mol of 1,4-butanediol were added to a reaction flask, the temperature was raised to 190° C., and the reaction was kept at this temperature for 4.3 h to obtain a mixture B;

[0077] S4. 1.03 mol of mixed material A and 1.7 mol of mixed material B were put into a reaction flask, heated to 243°C, kept warm for 54 min, 0.0405 g of tetrabutyl titanate was added and the pressure was reduced to -0.9 mPa, reacted for 54 min, and when the hydroxyl value was 38 mgKOH / g, the temperature was lowered and the material was discharged to obtain a linear component 2;

[0078] S5. 1.6 g of the linear component 1 and 0.8 g of the linear component 2 are mixed to obtain a linear polyester polyol, that is, polyester A;

[0079] S6. 0.0572 g of sodium dimethyl isophthalate-5-sulfonate, 1.02 mol of 1,6-hexanediol and 0.0230 g of monobutyltin oxide were mixed under a nitrogen atmosphere, heated to 194 ° C for 54 min, then cooled to 83 ° C, 1.11 mol of phthalic anhydride was added, heated to 217 ° C for 110 min, 7.15 g of xylene was added, and when the acid value dropped to 2 mgKOH / g, the temperature was lowered to 78 ° C to obtain a phthalic anhydride sulfonic acid type polyester polyol;

[0080] S7. 0.66 mol DOPO and 1.1 mol diethylene glycol were mixed, 0.73 mol maleic acid was added when the temperature was raised to 78°C, and after reacting at 78°C for 5.8 hours, 1.1 mol ethylene glycol and 1.04 mol adipic acid were added respectively, the temperature was raised to 148°C, 0.24 mol succinate was added, and the temperature was raised to 218°C until the acid value dropped to 2 mgKOH / g, and the material was discharged to obtain a phosphorus heterocyclic polyester polyol;

[0081] S8. 1.1 g of sulfonic acid-based polyester polyol and 0.7 g of phosphorus heterocyclic polyester polyol were mixed to obtain a rigid branched polyester polyol, namely, polyester B;

[0082] S9. 0.0568 g of sodium 5-sulfonate dimethyl isophthalate, 1.02 mol of 1,6-hexanediol and 0.0230 g of monobutyltin oxide were mixed under a nitrogen atmosphere, heated to 194° C. for 55 min, then cooled to 83° C., 1.11 mol of hexanediol was added, heated to 218° C. for 110 min, 7.18 g of xylene was added, and when the acid value dropped to 2 mgKOH / g, the temperature was lowered to 78° C. to obtain a phthalic anhydride sulfonic acid type polyester polyol;

[0083] S10. 1.02 mol of 1,6-hexanediol and 0.0228 g of monobutyltin oxide were mixed under a nitrogen atmosphere, heated to 194°C for 54 min, then cooled to 83°C, 1.11 mol of phthalic anhydride was added, heated to 218°C for 110 min, 7.12 g of xylene was added, and when the acid value dropped to 2 mgKOH / g, the temperature was lowered to 78°C to obtain a phthalic anhydride sulfonic acid type polyester polyol;

[0084] S11. 0.3 g of sulfonic acid type polyester polyol and 0.36 g of phthalic anhydride type polyester polyol were mixed to obtain a flexible branched polyester polyol, namely, polyester C;

[0085] S12. 2.4 g of polyester A, 1.8 g of polyester B and 0.7 g of polyester C are mixed evenly to obtain a low-viscosity polyester polyol.

[0086] Embodiment 4: A method for preparing a low-viscosity polyester polyol comprises the following steps:

[0087] S1. 2.15 mol 1,4-butanediol and 1.03 mol ethylene glycol were added to a reaction bottle, and then 1.3 mol adipic acid was added, the temperature was raised to 228°C, and the reaction was kept at this temperature for 56 minutes. 0.0438 g tetrabutyl titanate was added and the pressure was reduced to -0.85 mPa, and the reaction was continued for 56 minutes. When the hydroxyl value was 39 mg KOH / g, the temperature was lowered and the material was discharged to obtain a linear component 1;

[0088] S2. 1.04 mol of ethylene glycol and 2.04 mol of adipic acid were added to a reaction flask, the temperature was raised to 195° C., and the reaction was kept at this temperature for 4.4 hours to obtain a mixture A;

[0089] S3. 1.04 mol of adipic acid and 2.18 mol of 1,4-butanediol were added to a reaction flask, the temperature was raised to 195° C., and the reaction was kept at this temperature for 4.4 hours to obtain a mixture B;

[0090] S4. 1.04 mol of mixed material A and 1.8 mol of mixed material B were put into a reaction flask, heated to 244°C, kept warm for 56 min, 0.0416 g of tetrabutyl titanate was added, the pressure was reduced to -0.85 mPa, and the reaction was continued for 56 min. When the hydroxyl value was 39 mgKOH / g, the temperature was lowered and the material was discharged to obtain a linear component 2;

[0091] S5. 1.7 g of the linear component 1 and 0.9 g of the linear component 2 are mixed to obtain a linear polyester polyol, namely, polyester A;

[0092] S6. 0.0576 g of sodium dimethyl isophthalate-5-sulfonate, 1.02 mol of 1,6-hexanediol and 0.0231 g of monobutyltin oxide were mixed under a nitrogen atmosphere, heated to 196 ° C for 56 min, then cooled to 84 ° C, 1.12 mol of phthalic anhydride was added, heated to 219 ° C for 115 min, 7.21 g of xylene was added, and when the acid value dropped to 2.5 mgKOH / g, the temperature was lowered to 79 ° C to obtain a phthalic anhydride sulfonic acid type polyester polyol;

[0093] S7. 0.68 mol DOPO and 1.15 mol diethylene glycol were mixed, 0.74 mol maleic acid was added when the temperature was raised to 79°C, and after reacting at 79°C for 5.9 hours, 1.15 mol ethylene glycol and 1.05 mol adipic acid were added respectively, the temperature was raised to 149°C, 0.25 mol succinate was added, and the temperature was raised to 219°C until the acid value dropped to 2 mgKOH / g, and the material was discharged to obtain a phosphorus heterocyclic polyester polyol;

[0094] S8. 1.15 g of sulfonic acid-based polyester polyol and 0.8 g of phosphorus heterocyclic polyester polyol were mixed to obtain a rigid branched polyester polyol, namely, polyester B;

[0095] S9. 0.0575 g of sodium dimethyl isophthalate-5-sulfonate, 1.03 mol of 1,6-hexanediol and 0.0231 g of monobutyltin oxide were mixed under a nitrogen atmosphere, heated to 196° C. for 56 min, then cooled to 84° C., 1.12 mol of hexanediol was added, heated to 219° C. for 115 min, 7.21 g of xylene was added, and when the acid value dropped to 2.5 mg KOH / g, the temperature was lowered to 79° C. to obtain a phthalic anhydride sulfonic acid type polyester polyol;

[0096] S10. 1.03 mol of 1,6-hexanediol and 0.0231 g of monobutyltin oxide were mixed under a nitrogen atmosphere, heated to 196°C for 58 min, then cooled to 84°C, 1.12 mol of phthalic anhydride was added, heated to 219°C for 115 min, 7.19 g of xylene was added, and when the acid value dropped to 2.5 mgKOH / g, the temperature was lowered to 79°C to obtain a phthalic anhydride sulfonic acid type polyester polyol;

[0097] S11. 0.35 g of sulfonic acid type polyester polyol and 0.38 g of phthalic anhydride type polyester polyol were mixed to obtain a flexible branched polyester polyol, namely, polyester C;

[0098] S12. 2.6 g of polyester A, 1.9 g of polyester B and 0.8 g of polyester C are mixed evenly to obtain a low-viscosity polyester polyol.

[0099] Embodiment 5: A method for preparing a low-viscosity polyester polyol comprises the following steps:

[0100] S1. 2.2 mol 1,4-butanediol and 1.05 mol ethylene glycol were added to a reaction bottle, and then 1.4 mol adipic acid was added, the temperature was raised to 230°C, the temperature was kept for reaction for 60 min, 0.0468 g tetrabutyl titanate was added, the pressure was reduced to -0.8 mPa, and the reaction was continued for 60 min. When the hydroxyl value was 40 mg KOH / g, the temperature was lowered and the material was discharged to obtain a linear component 1;

[0101] S2. 1.05 mol of ethylene glycol and 2.05 mol of adipic acid were added to a reaction flask, the temperature was raised to 200°C, and the reaction was kept at this temperature for 4.5 hours to obtain a mixture A;

[0102] S3. 1.05 mol of adipic acid and 2.2 mol of 1,4-butanediol were added to a reaction flask, the temperature was raised to 200° C., and the reaction was kept at this temperature for 4.5 h to obtain a mixture B;

[0103] S4. 1.05 mol of mixed material A and 1.8 mol of mixed material B were put into a reaction flask, heated to 245°C, kept warm for 60 min, 0.0422 g of tetrabutyl titanate was added and the pressure was reduced to -0.8 mPa, reacted for 60 min, and when the hydroxyl value was 40 mgKOH / g, the temperature was lowered and the material was discharged to obtain a linear component 2;

[0104] S5. 1.8 g of the linear component 1 and 1 g of the linear component 2 are mixed to obtain a linear polyester polyol, namely, polyester A;

[0105] S6. 0.0578 g of sodium dimethyl isophthalate-5-sulfonate, 1.03 mol of 1,6-hexanediol and 0.0232 g of monobutyltin oxide were mixed under a nitrogen atmosphere, heated to 200 ° C for 60 min, then cooled to 85 ° C, 1.13 mol of phthalic anhydride was added, heated to 220 ° C for 120 min, 7.23 g of xylene was added, and when the acid value dropped to 3 mgKOH / g, the temperature was lowered to 80 ° C to obtain a phthalic anhydride sulfonic acid type polyester polyol;

[0106] S7. 0.7 mol DOPO and 1.2 mol diethylene glycol were mixed, 0.75 mol maleic acid was added when the temperature was raised to 80°C, and after reacting at 80°C for 6 hours, 1.2 mol ethylene glycol and 1.06 mol adipic acid were added respectively, the temperature was raised to 150°C, 0.26 mol succinate was added, and the temperature was raised to 220°C until the acid value dropped to 2 mgKOH / g, and the material was discharged to obtain a phosphorus heterocyclic polyester polyol;

[0107] S8. 1.2 g of sulfonic acid-based polyester polyol and 0.75 g of phosphorus heterocyclic polyester polyol were mixed to obtain a rigid branched polyester polyol, namely, polyester B;

[0108] S9. 0.0578 g of sodium dimethyl isophthalate-5-sulfonate, 1.03 mol of 1,6-hexanediol and 0.0232 g of monobutyltin oxide were mixed under a nitrogen atmosphere, heated to 200 ° C and kept for 60 min, then cooled to 85 ° C, 1.13 mol of hexanediol was added, the temperature was raised to 220 ° C and kept for 120 min, 7.23 g of xylene was added, and when the acid value dropped to 3 mgKOH / g, the temperature was lowered to 80 ° C and the material was discharged to obtain a phthalic anhydride sulfonic acid type polyester polyol;

[0109] S10. 1.03 mol of 1,6-hexanediol and 0.0232 g of monobutyltin oxide were mixed under a nitrogen atmosphere, heated to 200°C for 60 min, then cooled to 85°C, 1.13 mol of phthalic anhydride was added, heated to 220°C for 120 min, 7.23 g of xylene was added, and when the acid value dropped to 3 mgKOH / g, the temperature was lowered to 80°C to obtain a phthalic anhydride sulfonic acid type polyester polyol;

[0110] S11. 0.4 g of sulfonic acid type polyester polyol and 0.4 g of phthalic anhydride type polyester polyol were mixed to obtain a flexible branched polyester polyol, namely, polyester C;

[0111] S12. 2.8 g of polyester A, 2 g of polyester B and 0.8 g of polyester C are mixed evenly to obtain a low-viscosity polyester polyol.

[0112] Comparative Example 1:

[0113] Compared with Example 1, polyester A was not added in the preparation process of the low-viscosity polyester polyol in this comparative example, and the remaining steps and parameters were the same, which will not be repeated in this comparative example, and finally a low-viscosity polyester polyol was obtained.

[0114] Comparative Example 2:

[0115] Compared with Example 1, the present comparative example does not add polyester B during the preparation of the low-viscosity polyester polyol, and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a low-viscosity polyester polyol is obtained.

[0116] Comparative Example 3:

[0117] Compared with Example 1, the present comparative example does not add polyester C during the preparation of the low-viscosity polyester polyol, and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a low-viscosity polyester polyol is obtained.

[0118] Comparative Example 4:

[0119] Compared with Example 1, this comparative example only replaces "linear component 1" with "linear component 2", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a low-viscosity polyester polyol is obtained.

[0120] Comparative Example 5:

[0121] Compared with Example 1, this comparative example only replaces the "phthalic anhydride sulfonic acid type polyester polyol" with the "phosphorus heterocyclic polyester polyol", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a low-viscosity polyester polyol is obtained.

[0122] Comparative Example 6:

[0123] Compared with Example 1, this comparative example only replaces the "sulfonic acid type polyester polyol" with "phthalic anhydride type polyester polyol", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a low-viscosity polyester polyol is obtained.

[0124] Comparative Example 7:

[0125] Compared with Example 1, this comparative example only adjusts the amount of polyester A from 2g to 0.5g, and the amount of polyester C from 0.5g to 2g. The remaining steps and parameters are the same and will not be repeated in this comparative example. Finally, a low-viscosity polyester polyol is obtained.

[0126] Performance Test:

[0127] Determination of viscosity:

[0128] The viscosity of polyester polyol was measured by viscometer at a constant temperature of 58°C and the viscosity was read by changing the rotation speed.

[0129] Mechanical properties test:

[0130] Tensile strength and elongation at break are important means of characterizing the plasticizing effect of polyester polyols as plasticizers. Referring to the national standard GB1040.2-2006 for the determination of tensile properties of plastics, the mechanical properties of PVC plasticized with polyester were determined. The ACS-J universal mechanical tensile machine produced by Shimadzu Corporation of Japan was used. The thickness and width of the thinnest part of the cut dumbbell-shaped specimen were measured with a vernier caliper and recorded. The dumbbell-shaped specimen was clamped in a normal temperature mold. The test conditions were: the tensile rate was 30 mm / min, the program was selected as stretching, and the measurement was performed at room temperature of 25°C. The maximum tensile stress and maximum displacement were recorded, and the tensile strength and elongation at break of polyester polyol applied to PVC were calculated. The number of polyester polyols in the sample was 70 phr.

[0131] Migration resistance test:

[0132] As a plasticizer, polyester polyols will be exposed to various organic environments in the actual use environment, so they should have a certain resistance to solvent extraction. Solvent extraction resistance refers to cutting the PVC test piece using polyester polyol as a plasticizer into square pieces of the same size, immersing the sample in cyclohexane solvent, and placing it under constant temperature and humidity for 7 days. The sample is taken out and the organic solvent on the surface of the sample is absorbed with filter paper, and placed in a dryer for 24 hours. The weight is weighed and the migration rate of the polyester polyol is calculated. The experimental measurement conditions are: the PVC test piece plasticized by polyester polyol is cut into 5×5 square test pieces, weighed and embedded with activated carbon, placed under constant temperature and sealed conditions for 7 days, taken out and dried at constant temperature and weighed, and the solvent extraction resistance and volatility of the polyester polyol are calculated by the following formula, and the data when the number of polyester polyols in the sample is 70phr is recorded:

[0133]

[0134] Where, m is the original weight of the sample (g); m 1 is the mass of the sample after the migration test (g); a is the number of polyester polyols in the sample (phr); b is the fraction in the sample (phr);

[0135] The results are shown in Table 1 below:

[0136] Table 1

[0137]

[0138]

[0139] Data Analysis:

[0140] As can be seen from Table 1, the low-viscosity polyester polyol prepared by the present invention has a lower viscosity, and after being used for plasticizing PVC, it is found that the plasticized PVC test piece has a higher tensile strength and a lower elongation at break, which indicates that the addition of the polyester polyol effectively improves the plasticity of the PVC. The present invention prepares a polyester polyol by compounding a linear polyester polyol, a rigid branched polyester polyol and a flexible branched polyester polyol, and has strong fluidity and low viscosity, and also has a good plasticizing effect, and the material plasticized by the polyester polyol prepared by the present invention also has a higher thermal stability.

[0141] This may be because the rigid branched polyester polyol in the branched polyester polyol can interact with the groups on the PVC molecular chain to produce van der Waals force, which increases the tensile strength and mechanical properties of the PVC material, and effectively improves the thermal stability of the polyester polyol. In addition, the compounding of rigid branched polyester polyol and linear polyester polyol can increase the distance between PVC molecular chains, while the interaction force between PVC molecular chains is weakened, which increases the mobility of PVC molecular chains, thereby increasing plasticity. However, the rigid branched polyester polyol alone has a large side group volume, so its viscosity is also large. At this time, linear polyester polyol and flexible branched polyester polyol are introduced into the compounding. On the one hand, the flexible chain segment itself can interact with the PVC molecular chain, but because the relative content of the groups that can act is lower than that of rigid branched polyester polyol and flexible polyester polyol, it can effectively increase the fluidity of the system. Flexible branched polyester polyol effectively makes up for the defects of rigid branched polyol, such as high viscosity and reduced fluidity, caused by high crosslinking degree and branching degree. At the same time, the introduction of flexible branched polyester polyol can also maximize the compatibility of rigid branched polyester polyol and linear polyester polyol, thereby increasing the uniformity of the system.

[0142] However, in Comparative Example 7, the content of linear polyester polyol is reduced, while the content of flexible branched polyester polyol is increased. Finally, the PVC material plasticized by the linear polyester polyol has an increased number of groups that can interact with the PVC molecular chain, but the branching degree is too high, resulting in poor uniformity of the components in the system, resulting in a slight decrease in tensile strength, and an increase in viscosity and mobility compared with Example 1.

[0143] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0144] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a low-viscosity polyester polyol, characterized in that: The following steps are involved: The polyester A, polyester B and polyester C are mixed to obtain a low-viscosity polyester polyol; The polyester A is a linear polyester polyol; The polyester B is a rigid branched polyester polyol; The polyester C is a flexible branched polyester polyol; The linear polyester polyol is obtained by mixing a linear component 1 and a linear component 2; The linear component 1 and the linear component 2 are both prepared from 1,4-butanediol, ethylene glycol and adipic acid; The rigid branched polyester polyol is obtained by mixing a phthalic anhydride sulfonic acid type polyester polyol and a phosphorus heterocyclic type polyester polyol; The phosphorus heterocyclic polyester polyol contains a biphenyl ring and a phenanthrene ring; The flexible branched polyester polyol is obtained by mixing a sulfonic acid type polyester polyol and a phthalic anhydride type polyester polyol.

2. The method for preparing a low-viscosity polyester polyol according to claim 1, characterized in that: The preparation process of the linear component 1 is as follows: Put 1,4-butanediol and ethylene glycol into a reaction bottle, then add adipic acid, raise the temperature to 225-230°C, keep the temperature for reaction for 50-60 minutes, add tetrabutyl titanate and reduce the pressure to -1-0.8mPa, react for 50-60 minutes, and when the hydroxyl value is 34-40mgKOH / g, cool and discharge the material to obtain linear component 1; The usage ratio of 1,4-butanediol, ethylene glycol, adipic acid and tetrabutyl titanate is 2-2.2 mol: 1-1.05 mol: 1-1.4 mol: 0.0388-0.0468 g.

3. The method for preparing low-viscosity polyester polyol according to claim 1, characterized in that: The preparation process of the linear component 2 is as follows: Step A1. Add ethylene glycol and adipic acid into a reaction flask, heat to 180-200°C, and keep the temperature for 4-4.5 hours to obtain a mixture A; Step A2. Add adipic acid and 1,4-butanediol into a reaction flask, raise the temperature to 180-200°C, and keep the temperature for 4-4.5 hours to obtain a mixture B; Step A3. Add mixture A and mixture B into a reaction bottle, heat to 240-245°C, keep warm for 50-60 minutes, add tetrabutyl titanate and reduce the pressure to -1-0.8 mPa, react for 50-60 minutes, and when the hydroxyl value is 34-40 mgKOH / g, cool and discharge to obtain linear component 2.

4. The method for preparing a low-viscosity polyester polyol according to claim 3, characterized in that: The molar ratio of ethylene glycol to adipic acid in step A1 is 1-1.05:2-2.05; The molar ratio of adipic acid to 1,4-butanediol in step A2 is 1-1.05:2.05-2.2; In step A3, the usage ratio of mixed material A, mixed material B and tetrabutyl titanate is 1-1.05 mol:1.5-1.8 mol:0.0362-0.0422 g.

5. The method for preparing low-viscosity polyester polyol according to claim 1, characterized in that: The preparation process of the phthalic anhydride sulfonic acid type polyester polyol is as follows: Mix dimethyl isophthalate-5-sulfonic sodium salt, 1,6-hexanediol and monobutyltin oxide under nitrogen atmosphere, heat to 190-200°C and keep warm for 50-60 minutes, then cool to 80-85°C, add phthalic anhydride, heat to 215-220°C and keep warm for 100-120 minutes, add xylene, and when the acid value drops to 1-3 mgKOH / g, cool to 75-80°C and discharge to obtain phthalic anhydride sulfonic acid type polyester polyol; The usage ratio of dimethyl isophthalate-5-sodium sulfonate, 1,6-hexanediol, monobutyltin oxide, phthalic anhydride and xylene is 0.0559-0.0578g: 1-1.03mol: 0.0224-0.0232g: 1.09-1.13mol: 6.99-7.23g.

6. The method for preparing low-viscosity polyester polyol according to claim 1, characterized in that: The preparation process of the phosphorus heterocyclic polyester polyol is as follows: Mix DOPO and diethylene glycol, add maleic acid when the temperature rises to 75-80°C, react at 75-80°C for 5.5-6h, add ethylene glycol and adipic acid respectively, heat to 145-150°C, add cycerol, and then heat to 215-220°C until the acid value drops to 2mgKOH / g, discharge the material, and obtain phosphorus heterocyclic polyester polyol; The molar ratio of DOPO, diethylene glycol, maleic acid, ethylene glycol, adipic acid and sec is 0.6-0.7:1-1.2:0.7-0.75:1-1.2:1-1.06:0.2-0.

26.

7. The method for preparing low-viscosity polyester polyol according to claim 1, characterized in that: The preparation process of the sulfonic acid type polyester polyol is as follows: Mix dimethyl isophthalate-5-sulfonic sodium salt, 1,6-hexanediol and monobutyltin oxide under nitrogen atmosphere, heat to 190-200°C and keep warm for 50-60 minutes, then cool to 80-85°C, add hexanediol, heat to 215-220°C and keep warm for 100-120 minutes, add xylene, and when the acid value drops to 1-3 mgKOH / g, cool to 75-80°C and discharge to obtain phthalic anhydride sulfonic acid type polyester polyol; The usage ratio of dimethyl isophthalate-5-sodium sulfonate, 1,6-hexanediol, monobutyltin oxide, hexanediol and xylene is 0.0559-0.0578g: 1-1.03mol: 0.0224-0.0232g: 1.09-1.13mol: 6.99-7.23g.

8. The method for preparing low-viscosity polyester polyol according to claim 1, characterized in that: The preparation process of the phthalic anhydride type polyester polyol is as follows: Mix 1,6-hexanediol and monobutyltin oxide under nitrogen atmosphere, heat to 190-200°C and keep warm for 50-60 minutes, then cool to 80-85°C, add phthalic anhydride, heat to 215-220°C and keep warm for 100-120 minutes, add xylene, and when the acid value drops to 1-3 mgKOH / g, cool to 75-80°C and discharge to obtain phthalic anhydride sulfonic acid type polyester polyol; The usage ratio of the 1,6-hexanediol, monobutyltin oxide, phthalic anhydride and xylene is 1-1.03 mol: 0.0224-0.0232 g: 1.09-1.13 mol: 6.99-7.23 g.

9. The method for preparing low-viscosity polyester polyol according to claim 1, characterized in that: The mass ratio of polyester A, polyester B and polyester C is 2-2.8:1.5-2:0.5-0.

8.

10. The method for preparing low-viscosity polyester polyol according to claim 1, characterized in that: The mass ratio of the linear component 1 to the linear component 2 in the linear polyester polyol is 1.4-1.8:0.6-1; The mass ratio of the phthalic anhydride sulfonic acid polyester polyol to the phosphorus heterocyclic polyester polyol in the rigid branched polyester polyol is 1-1.2:0.5-0.8; The mass ratio of the sulfonic acid type polyester polyol to the phthalic anhydride type polyester polyol in the flexible branched polyester polyol is 0.2-0.4:0.3-0.4.

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