Polyester polyol and its preparation method and application

Abstract

The application discloses polyester polyol and a preparation method and application thereof. The polyester polyol comprises the following steps: 1) tetradecanedioic acid, 1,6-hexanediol and a catalyst are added into a reaction kettle to generate a polyester intermediate through esterification and polycondensation; and 2) then glycolide is added into the reaction kettle to continue the reaction to obtain the polyester polyol. The polyester polyol obtained through the process has high crystallinity and high glass transition temperature, and the PUR hot melt adhesive prepared from the polyester polyol can meet the requirement of high initial bonding strength of the PUR hot melt adhesive on different polar substrates, improves the universality of the polyester polyol and the PUR adhesive product, simplifies the formula design and production of downstream customers, and improves the user recognition and use convenience.

Description

Technical Field

[0001] This invention relates to a polyester polyol, and more particularly to a polyester polyol and its preparation method and application. Background Technology

[0002] PUR adhesives are widely used in woodworking, textiles, automobiles, home appliances and other fields. They have attracted widespread attention for their environmental friendliness, ease of use and excellent bonding performance. In recent years, the market usage of PUR adhesives has been gradually increasing.

[0003] Polyester polyols are a crucial raw material for PUR adhesives, and their structure and properties significantly impact the performance of these products. To meet the diverse application requirements of downstream adhesive manufacturers, polyester manufacturers need to develop differentiated products with various structures, as a single product cannot achieve universal applicability. Currently, PUR polyester polyols mainly include three types: crystalline, amorphous, and liquid, each offering different properties. Liquid polyester primarily provides wetting properties; crystalline polyester polyols mainly shorten the open time and increase initial strength of PUR hot melt adhesives; and amorphous polyester primarily improves the adhesive strength of PUR hot melt adhesives. Downstream PUR adhesive manufacturers also need to adjust the proportions of several different types of polyester polyols according to the application scenario during formulation design, making formulation design and production operations quite complex. Furthermore, while current PUR adhesives exhibit good adhesion to highly polar materials, they have poor adhesion to low-polarity substrates, and the polyester polyol structure needs to be adjusted according to the material's polarity, making the process complex. If the same universal polyester polyol raw material could be used to achieve the effect of multiple polyester polyol blends and simultaneously meet the bonding requirements of various materials, it would greatly improve the convenience for PUR adhesive manufacturers. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a polyester polyol, its preparation method, and its applications. The polyester polyol prepared by this invention exhibits both crystallinity and amorphous properties, demonstrating broad versatility. Furthermore, the PUR adhesive prepared from the polyester polyol of this invention exhibits excellent adhesion to both non-polar and polar substrates, satisfying the bonding requirements of various materials and significantly improving operational convenience for downstream manufacturers.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a polyester polyol includes the following steps:

[0007] 1) Tetradecanoic acid, 1,6-hexanediol and catalyst are added to a reaction vessel and esterified polycondensation reaction is carried out to generate polyester intermediates;

[0008] 2) Then, glycolide is added to the reactor to continue the reaction, and polyester polyol is obtained.

[0009] As some preferred embodiments of the present invention, in step 1), the molar ratio of 1,6-hexanediol to tetradecanoic acid is 1.02-1.2.

[0010] As some preferred embodiments of the present invention, in step 1), the catalyst is selected from at least one of organotin, organotitanium, organobismuth, and organoantimony, preferably one or more of stannous octoate, dibutyltin dilaurate, stannous acetate, diisopropyl titanate, tetraisopropyl titanate, tetrabutyl titanate, antimony trioxide, bismuth triacetate, bismuth trilaurate, and bismuth trioxide.

[0011] Preferably, the catalyst is added at a rate of 0-2000 ppm of the total mass of tetradecanoic acid and 1,6-hexanediol, more preferably 20-500 ppm.

[0012] As some preferred embodiments of the present invention, in step 1), the reaction temperature is first controlled at 190-260°C and the reaction time is 5-20h; then the reaction pressure is adjusted to below -80kPaG, vacuum polycondensation is carried out, and the reaction continues for 1-30h, preferably 4-20h.

[0013] As some preferred embodiments of the present invention, in step 2), the amount of glycolide added accounts for 5-30% of its total mass with the polyester intermediate.

[0014] As some preferred embodiments of the present invention, in step 2), the reaction temperature is 120-190°C, preferably 140-180°C; and / or the reaction time is 1-10h.

[0015] As some preferred embodiments of the present invention, in step 2), the moisture content of glycolide needs to be controlled to be <30ppm before it is added to the system.

[0016] The present invention also provides a polyester polyol prepared by the method described above.

[0017] The present invention also provides a PUR hot melt adhesive, comprising the following components by weight:

[0018] 25-60 parts of polyester polyol

[0019] 5-20 parts of liquid polyester

[0020] 10-30 parts of filler

[0021] 1-10 parts isocyanate

[0022] 2-15 parts of polyether polyol

[0023] 5-20 parts of tackifying resin;

[0024] Wherein, the polyester polyol is a polyester polyol prepared using the method described above in this invention;

[0025] Preferably, the liquid polyester is a diacid / diol copolymer with a functionality of 2 and which is liquid at room temperature, and more preferably a copolymer with a molecular weight of 1000-7000;

[0026] The optional dicarboxylic acids include, but are not limited to, C2-C18 straight-chain or branched saturated aliphatic diacids and aromatic diacids; the optional diols include, but are not limited to, C2-C10 straight-chain or branched saturated aliphatic diols.

[0027] Preferably, the filler is selected from one or more of calcium carbonate, talc, silica, alumina, titanium dioxide, wood flour, and cellulose;

[0028] Preferably, the isocyanate is selected from aliphatic, alicyclic, and aromatic diisocyanates, and more preferably one or more of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), and lysine diisocyanate (LDI).

[0029] Preferably, the polyether polyol is a polyether polyol with a functionality of 2 and a molecular weight of 500-3000;

[0030] Preferably, the tackifying resin is selected from one or more of terpene resin, EVA resin, rosin glycerol ester, rosin pentaerythritol ester, hydrogenated rosin ester, petroleum resin, polyurethane resin, and polyamide resin.

[0031] The present invention also provides an application of the PUR hot melt adhesive as described above in the fields of electronics, automobiles, construction, office supplies, and textiles.

[0032] The polyester polyol obtained by the process of this invention has high crystallinity and high glass transition temperature. Moreover, the PUR hot melt adhesive prepared from it can meet the requirements of high initial bond strength of PUR hot melt adhesive for substrates with different polarities, improve the versatility of polyester polyol and PUR adhesive products, simplify the formulation design and production of downstream customers, and improve user acceptance and ease of use. Detailed Implementation

[0033] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0034] The main testing methods involved in the following embodiments of the present invention are as follows:

[0035] The hydroxyl value test for products should refer to HG / T 2709-2022;

[0036] The acid value test for the product should refer to HG / T 2708-1995;

[0037] The product viscosity was tested using a Boller Feinberg cone-plate viscometer.

[0038] The crystallization temperature and glass transition temperature of the product were tested using a Mettler Toledo DSC3 differential scanning calorimeter.

[0039] The peel strength of PUR hot melt adhesive was tested using a universal testing machine.

[0040] The main raw material information in the following embodiments of the present invention is as follows. Unless otherwise specified, other raw materials and reagents can be purchased from commercially available finished products.

[0041] EVA resin: Dow ELVAX 410; VA content: 18%

[0042] Polyester polyol A: Evonik Dynacoll 7380, molecular weight 3500, melting point 77℃;

[0043] Polyester polyol B: Evonik Dynacoll 7130, molecular weight 3000, T g =30℃;

[0044] Example 1

[0045] 1) Add 2000g tetradecanoic acid, 988g 1,6-hexanediol and 0.090g stannous octoate to the reactor. After nitrogen purging, set the reactor temperature to 200℃ and react for 16h. The rate of water distillation from the top of the distillation column begins to decrease. Set the vacuum pump pressure to -90kPaG and begin evacuating the reactor. Continue the reaction for 23h to obtain a polyester intermediate. The acid value is 1.23mgKOH / g and the hydroxyl value is 17.34mgKOH / g.

[0046] 2) Take 1000g of the polyester intermediate obtained in step 1) and 200g of glycolide and add them to a reactor. Set the reactor temperature to 160℃ and close the reactor for 7 hours to obtain polyester polyol 1. The product has an acid value of 1.32mgKOH / g, a hydroxyl value of 14.17mgKOH / g, a viscosity of 2800cP at 130℃, a crystallization temperature of 90℃, and a glass transition temperature of 47℃.

[0047] Example 2

[0048] 1) Add 2000g tetradecanoic acid, 1006g 1,6-hexanediol and 0.601g isopropyl titanate to the reactor. After nitrogen purging, set the reactor temperature to 210℃ and react for 10h. The rate of water distillation from the top of the distillation column begins to decrease. Set the vacuum pump pressure to -94kPaG and begin evacuating the reactor. Continue the reaction for 19h to obtain a polyester intermediate. The acid value is 0.78mgKOH / g and the hydroxyl value is 27.56mgKOH / g.

[0049] 2) Take 1000g of the polyester intermediate obtained in step 1) and 250g of glycolide and add them to a reactor. Set the reactor temperature to 180℃ and react for 4 hours to obtain polyester polyol 2. The product has an acid value of 0.92mgKOH / g, a hydroxyl value of 22.11mgKOH / g, a viscosity of 2100cP at 130℃, a crystallization temperature of 86℃, and a glass transition temperature of 58℃.

[0050] Example 3

[0051] 1) Add 2000g tetradecanoic acid, 1025g 1,6-hexanediol and 0.907g tetrabutyl titanate to the reactor. After nitrogen purging, set the reactor temperature to 230℃ and react for 7h. The rate of water distillation from the top of the distillation column begins to decrease. Set the vacuum pump pressure to -78kPaG and start evacuating the reactor. Continue the reaction for 7h to obtain a polyester intermediate. The acid value is 0.69mgKOH / g and the hydroxyl value is 36.01mgKOH / g.

[0052] 2) Take 1000g of the polyester intermediate obtained in step 1) and 500g of glycolide and add them to the reactor. Set the reactor temperature to 140℃ and close the reactor for 2 hours to obtain polyester polyol 3. The product has an acid value of 0.74mgKOH / g, a hydroxyl value of 23.78mgKOH / g, a viscosity of 3000cP at 130℃, a crystallization temperature of 87℃, and a glass transition temperature of 62℃.

[0053] Example 4

[0054] 1) Add 2000g tetradecanoic acid, 1089g 1,6-hexanediol and 3.089g bismuth triacetate to the reactor. After nitrogen purging, set the reactor temperature to 240℃ and react for 5h. The rate of water distillation from the top of the distillation column begins to decrease. Set the vacuum pump pressure to -85kPaG and start evacuating the reactor. Continue the reaction for 4h to obtain a polyester intermediate. The acid value is 0.58mgKOH / g and the hydroxyl value is 55.01mgKOH / g.

[0055] 2) Take 1000g of the polyester intermediate obtained in step 1) and 800g of glycolide and add them to the reactor. Set the reactor temperature to 125℃ and close the reactor for 6 hours to obtain polyester polyol 4. The product has an acid value of 0.70mgKOH / g, a hydroxyl value of 32mgKOH / g, a viscosity of 2100cP at 130℃, a crystallization temperature of 83℃, and a glass transition temperature of 70℃.

[0056] Application Example 1-4, Comparative Application Example 1-2

[0057] PUR hot melt adhesives were prepared using different polyester polyols as raw materials, following the same formula (parts by weight), and the performance tests shown in Table 1 were performed:

[0058] 37 parts of polyester polyol,

[0059] Evonik Dynacoll 7250 15 units

[0060] MDI-50 6.1 parts,

[0061] 24 parts of calcium carbonate

[0062] 10 copies of PPG1000

[0063] 7.9 parts of EVA resin.

[0064] Performance testing methods include:

[0065] Peel strength test shall be performed in accordance with ISO 8510-2:2006.

[0066] Opening time testing shall be conducted in accordance with ISO 17212:2012.

[0067] Table 1. Performance Evaluation

[0068]

[0069]

[0070] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a polyester polyol, characterized in that, Includes the following steps: 1) Tetradecanoic acid, 1,6-hexanediol and catalyst are added to a reaction vessel and esterified polycondensation reaction is carried out to generate polyester intermediates; 2) Then, glycolide is added to the reactor to continue the reaction, yielding polyester polyol; In step 1), the molar ratio of 1,6-hexanediol to tetradecanoic acid is 1.02-1.2; In step 2), the amount of glycolide added accounts for 5-30% of its total mass with the polyester intermediate; In step 2), the moisture content of glycolide must be controlled to be <30ppm before it is added to the system.

2. The method for preparing polyester polyol according to claim 1, characterized in that, In step 1), the catalyst is selected from at least one of organotin, organotitanium, organobismuth, and organoantimony.

3. The method for preparing polyester polyol according to claim 2, characterized in that, In step 1), the catalyst is selected from one or more of the following: stannous octoate, dibutyltin dilaurate, stannous acetate, diisopropyl titanate, tetraisopropyl titanate, tetrabutyl titanate, antimony trioxide, bismuth triacetate, bismuth trilaurate, and bismuth trioxide.

4. The method for preparing polyester polyol according to claim 2, characterized in that, The catalyst is added at a rate of 0-2000 ppm of the total mass of tetradecanoic acid and 1,6-hexanediol.

5. The method for preparing polyester polyol according to claim 2, characterized in that, The catalyst is added at a rate of 20-500 ppm of the total mass of tetradecanoic acid and 1,6-hexanediol.

6. The method for preparing polyester polyol according to any one of claims 1-5, characterized in that, In step 1), the reaction temperature is first controlled at 190-260℃ and the reaction time is 5-20h; then the reaction pressure is adjusted to below -80kPaG to carry out vacuum polycondensation and continue the reaction for 1-30h.

7. The method for preparing polyester polyol according to claim 6, characterized in that, In step 1), vacuum polycondensation is carried out, and the reaction continues for 4-20 hours.

8. The method for preparing polyester polyol according to any one of claims 1-5, characterized in that, In step 2), the reaction temperature is 120-190℃; and / or the reaction time is 1-10h.

9. The method for preparing polyester polyol according to claim 8, characterized in that, In step 2), the reaction temperature is 140-180℃.

10. A polyester polyol prepared by the method according to any one of claims 1-9.

11. A PUR hot melt adhesive, characterized in that, Based on parts by weight, it includes the following components: 25-60 parts of polyester polyol 5-20 parts of liquid polyester 10-30 parts of filler 1-10 parts isocyanate 2-15 parts of polyether polyol 5-20 parts of EVA tackifying resin; The polyester polyol is a polyester polyol prepared by the method according to any one of claims 1-9.

12. The PUR hot melt adhesive according to claim 11, characterized in that, The liquid polyester is a dicarboxylic acid / diol copolymer with a functionality of 2 and which is liquid at room temperature.

13. The PUR hot melt adhesive according to claim 12, characterized in that, The liquid polyester is a copolymer with a molecular weight of 1000-7000.

14. The PUR hot melt adhesive according to claim 12, characterized in that, The filler is selected from one or more of calcium carbonate, talc, silica, alumina, titanium dioxide, wood flour, and cellulose.

15. The PUR hot melt adhesive according to claim 12, characterized in that, The isocyanate is selected from aliphatic, alicyclic, and aromatic diisocyanates.

16. The PUR hot melt adhesive according to claim 15, characterized in that, The isocyanate is selected from one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and lysine diisocyanate.

17. The PUR hot melt adhesive according to claim 12, characterized in that, The polyether polyol is a polyether polyol with a functionality of 2 and a molecular weight of 500-3000.

18. The PUR hot melt adhesive according to claim 12, characterized in that, The tackifying resin is selected from one or more of terpene resin, EVA resin, rosin glycerol ester, rosin pentaerythritol ester, hydrogenated rosin ester, petroleum resin, polyurethane resin, and polyamide resin.

19. The application of the PUR hot melt adhesive as described in any one of claims 11-18 in the fields of electronics, automobiles, construction, office supplies, and textiles.

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