Polyester polyol as well as preparation method and application thereof

Abstract

The invention discloses polyester polyol as well as a preparation method and application thereof. The preparation method comprises the following steps: 1) adding tetradecanedioic acid, 1, 6-hexanediol and a catalyst into a reaction kettle, and carrying out esterification polycondensation reaction to generate a polyester intermediate; and 2) adding glycolide into the reaction kettle for continuous reaction to obtain the polyester polyol. The polyester polyol obtained by the process has high crystallinity and high glass transition temperature, the PUR hot melt adhesive prepared from the polyester polyol can meet the requirement of the PUR hot melt adhesive for high initial bonding strength of substrates with different polarities, the universality of the polyester polyol and PUR adhesive products is improved, the formula design and production of downstream customers are simplified, and the production cost is reduced. And the user recognition degree and the use convenience degree are improved.

Description

Technical Field

[0001] The invention relates to a polyester polyol, in particular to a polyester polyol and a preparation method and application thereof. Background Art

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

[0003] Polyester polyol is one of the important raw materials of PUR adhesive. Its structure and index have a great influence on the performance of adhesive products. In order to meet the requirements of downstream adhesive manufacturers for different application conditions, polyester manufacturers need to develop differentiated products with various structures. It is difficult for a single product to be universally applied. At present, polyester polyols for PUR mainly include three types: crystalline, amorphous and liquid, each of which can provide different performance. Among them, liquid polyester mainly provides wetting properties; crystalline polyester polyol mainly provides the effect of shortening the opening time and increasing the initial strength of PUR hot melt adhesive in the early stage; amorphous polyester mainly improves the bonding strength of PUR hot melt adhesive. In the process of formula design by downstream PUR adhesive manufacturers, it is also necessary to adjust the proportions of several different types of polyester polyols according to the application scenario requirements, which makes the formula design and production operation more complicated. In addition, the current PUR adhesive has good adhesion to high-polarity materials, but poor adhesion to low-polarity substrates, and the structure of polyester polyol needs to be adjusted according to the different polarities of the materials, which is more complicated to operate. If the same universal polyester polyol raw material can be used to achieve the effect of compounding multiple polyester polyols and meet the bonding requirements of multiple materials, the convenience of PUR adhesive manufacturers will be greatly improved. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a polyester polyol and a preparation method and application thereof. The polyester polyol prepared by the present invention has the characteristics of both crystallinity and amorphism, and has wide versatility. In addition, the PUR adhesive prepared by the polyester polyol in the present invention has good adhesion to both non-polar substrates and polar substrates, can meet the bonding of a variety of different materials, and greatly improves the operational convenience of downstream manufacturers.

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

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

[0007] 1) adding tetradecanedioic acid, 1,6-hexanediol and a catalyst into a reaction kettle to generate a polyester intermediate through an esterification polycondensation reaction;

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

[0009] As some preferred embodiments of the present invention, in step 1), the molar ratio of 1,6-hexanediol to tetradecanedioic 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 organic tin, organic titanium, organic bismuth, and organic antimony, 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 in an amount of 0-2000 ppm, preferably 20-500 ppm, based on the total mass of tetradecanedioic acid and 1,6-hexanediol.

[0012] As some preferred schemes of the present invention, in step 1), firstly, the reaction temperature is controlled to be 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 is continued for 1-30h, preferably 4-20h.

[0013] As some preferred embodiments of the present invention, in step 2), the amount of glycolide added is 5-30% of the total mass of glycolide and 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 1-10 h.

[0015] As some preferred embodiments of the present invention, in step 2), the water content of glycolide should be controlled to be less than 30 ppm before adding into 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, which comprises the following components in parts by mass:

[0018] Polyester polyol 25-60 parts,

[0019] 5-20 parts of liquid polyester,

[0020] 10-30 parts of filler,

[0021] Isocyanate 1-10 parts,

[0022] 2-15 parts of polyether polyol,

[0023] 5-20 parts of tackifying resin;

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

[0025] Preferably, the liquid polyester is a dibasic acid / diol copolymer having a functionality of 2 and being liquid at room temperature, preferably a copolymer having a molecular weight of 1000-7000;

[0026] Optionally, the dibasic acid includes but is not limited to C2-C18 straight chain or branched saturated aliphatic diacids and aromatic diacids; optionally, the dihydric alcohol includes but is 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, silicon dioxide, aluminum oxide, titanium dioxide, wood flour, and cellulose;

[0028] Preferably, the isocyanate is selected from aliphatic, alicyclic, and aromatic diisocyanates, 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 having 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 the present invention has high crystallinity and high glass transition temperature, and the PUR hot melt adhesive prepared therefrom can meet the requirements of high initial bonding strength of the PUR hot melt adhesive to substrates of different polarities, thereby improving the versatility of polyester polyol and PUR adhesive products, simplifying the formula design and production of downstream customers, and improving user recognition and ease of use. DETAILED DESCRIPTION

[0033] The present invention is further described below by means of specific examples. The examples described in the present invention are only used to illustrate the present invention and do not limit the scope of the present invention.

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

[0035] The product hydroxyl value test refers to HG / T 2709-2022;

[0036] Product acid value test refers to HG / T 2708-1995;

[0037] The product viscosity test is carried out using a Boller cone and 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 examples of the present invention is as follows. Unless otherwise specified, other raw materials and reagents can be purchased from commercially available products.

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

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

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

[0044] Example 1

[0045] 1) Add 2000g of tetradecanedioic acid, 988g of 1,6-hexanediol and 0.090g of stannous octoate to the reactor. After nitrogen substitution, set the reactor temperature to 200°C, react for 16 hours, and the rate of water distilled from the top of the distillation tower begins to decrease; set the vacuum pump pressure to -90kPaG, start to evacuate the reactor, continue to react for 23 hours, and obtain a polyester intermediate. The acid value is 1.23mgKOH / g and the hydroxyl value is 17.34mgKOH / g.

[0046] 2) 1000 g of the polyester intermediate obtained in step 1) and 200 g of glycolide were added to a reactor, the reactor temperature was set to 160° C., the reactor was closed and reacted for 7 hours to obtain polyester polyol 1. The product had an acid value of 1.32 mgKOH / g, a hydroxyl value of 14.17 mgKOH / g, a viscosity of 2800 cP at 130° C., a crystallization temperature of 90° C., and a glass transition temperature of 47° C.

[0047] Example 2

[0048] 1) Add 2000g of tetradecanedioic acid, 1006g of 1,6-hexanediol and 0.601g of isopropyl titanate to the reactor. After nitrogen substitution, set the reactor temperature to 210°C, react for 10 hours, and the rate of water distilled from the top of the distillation tower begins to decrease; set the vacuum pump pressure to -94kPaG, start to evacuate the reactor, continue to react for 19 hours, and obtain a polyester intermediate. The tested acid value is 0.78mgKOH / g and the hydroxyl value is 27.56mgKOH / g.

[0049] 2) 1000 g of the polyester intermediate obtained in step 1) and 250 g of glycolide were added to a reactor, the reactor temperature was set to 180° C., the reactor was closed and reacted for 4 hours to obtain polyester polyol 2. The product had an acid value of 0.92 mgKOH / g, a hydroxyl value of 22.11 mgKOH / g, a viscosity of 2100 cP at 130° C., a crystallization temperature of 86° C., and a glass transition temperature of 58° C.

[0050] Example 3

[0051] 1) Add 2000g of tetradecanedioic acid, 1025g of 1,6-hexanediol and 0.907g of tetrabutyl titanate to the reactor. After nitrogen substitution, set the reactor temperature to 230°C, react for 7h, and the rate of water distilled from the top of the distillation tower begins to decrease; set the vacuum pump pressure to -78kPaG, start to evacuate the reactor, continue to react for 7h, and obtain a polyester intermediate. The tested acid value is 0.69mgKOH / g and the hydroxyl value is 36.01mgKOH / g.

[0052] 2) 1000 g of the polyester intermediate obtained in step 1) and 500 g of glycolide were added to a reactor, the reactor temperature was set to 140° C., and the reactor was closed for reaction for 2 hours to obtain polyester polyol 3. The product had an acid value of 0.74 mgKOH / g, a hydroxyl value of 23.78 mgKOH / g, a viscosity of 3000 cP at 130° C., a crystallization temperature of 87° C., and a glass transition temperature of 62° C.

[0053] Example 4

[0054] 1) Add 2000g of tetradecanedioic acid, 1089g of 1,6-hexanediol and 3.089g of bismuth triacetate to a reactor. After nitrogen substitution, set the reactor temperature to 240°C, react for 5 hours, and the rate of water distilled from the top of the distillation tower begins to decrease; set the vacuum pump pressure to -85kPaG, start evacuating the reactor, continue the reaction for 4 hours, and obtain a polyester intermediate. The tested acid value is 0.58mgKOH / g and the hydroxyl value is 55.01mgKOH / g.

[0055] 2) 1000 g of the polyester intermediate obtained in step 1) and 800 g of glycolide were added to a reactor, the reactor temperature was set to 125° C., and the reactor was closed for reaction for 6 hours to obtain polyester polyol 4. The product had an acid value of 0.70 mgKOH / g, a hydroxyl value of 32 mgKOH / g, a viscosity of 2100 cP at 130° C., a crystallization temperature of 83° C., and a glass transition temperature of 70° C.

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

[0057] Different polyester polyols were used as raw materials, and PUR hot melt adhesives were prepared according to the following 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 parts,

[0060] MDI-50 6.1 parts,

[0061] Calcium carbonate 24 parts,

[0062] PPG1000 10 parts,

[0063] 7.9 parts of EVA resin.

[0064] Performance testing methods include:

[0065] Peel strength test according to ISO 8510-2:2006

[0066] Open time test according to ISO 17212:2012

[0067] Table 1. Performance evaluation

[0068]

[0069]

[0070] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing polyester polyol, characterized in that: The following steps are involved: 1) adding tetradecanedioic acid, 1,6-hexanediol and a catalyst into a reaction kettle to generate a polyester intermediate through esterification and polycondensation reaction; 2) Then, glycolide is added into the reactor to continue the reaction to obtain polyester polyol.

2. The method for preparing polyester polyol according to claim 1, characterized in that: In step 1), the molar ratio of 1,6-hexanediol to tetradecanedioic acid is 1.02-1.

2.

3. 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 organic tin, organic titanium, organic bismuth, and organic antimony, 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; Preferably, the catalyst is added in an amount of 0-2000 ppm, preferably 20-500 ppm, based on the total mass of tetradecanedioic acid and 1,6-hexanediol.

4. The method for preparing a polyester polyol according to any one of claims 1 to 3, characterized in that: In step 1), the reaction temperature is first controlled to be 190-260° C. and the reaction time is 5-20 h; then the reaction pressure is adjusted to below -80 kPaG, vacuum polycondensation is performed, and the reaction is continued for 1-30 h, preferably 4-20 h.

5. The method for preparing a polyester polyol according to any one of claims 1 to 4, characterized in that: In step 2), the amount of glycolide added is 5-30% of the total mass of glycolide and the polyester intermediate.

6. The method for preparing a polyester polyol according to any one of claims 1 to 5, characterized in that: In step 2), the reaction temperature is 120-190° C., preferably 140-180° C.; and / or the reaction time is 1-10 h.

7. The method for preparing a polyester polyol according to any one of claims 1 to 6, characterized in that: In step 2), the water content of glycolide should be controlled to be less than 30 ppm before adding the glycolide into the system.

8. A polyester polyol prepared by the method according to any one of claims 1 to 7.

9. A PUR hot melt adhesive, characterized in that: According to the weight percentage, it includes the following components: Polyester polyol 25-60 parts, 5-20 parts of liquid polyester, 10-30 parts of filler, Isocyanate 1-10 parts, 2-15 parts of polyether polyol, 5-20 parts of EVA tackifying resin; Wherein, the polyester polyol is a polyester polyol prepared by the method described in any one of claims 1 to 7; Preferably, the liquid polyester is a dibasic acid / diol copolymer having a functionality of 2 and being liquid at room temperature, preferably a copolymer having a molecular weight of 1000-7000; Preferably, the filler is selected from one or more of calcium carbonate, talc, silicon dioxide, aluminum oxide, titanium dioxide, wood flour, and cellulose; Preferably, the isocyanate is selected from aliphatic, alicyclic, and aromatic diisocyanates, preferably one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and lysine diisocyanate; Preferably, the polyether polyol is a polyether polyol having a functionality of 2 and a molecular weight of 500-3000; 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.

10. Use of the PUR hot melt adhesive as claimed in claim 9 in the fields of electronics, automobiles, construction, office supplies and textiles.

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