Waterborne polyurethane adhesive with high heat resistance, high initial adhesion and high ductility and preparation method thereof

Abstract

The invention discloses a waterborne polyurethane adhesive with high heat resistance, high initial adhesion and high ductility and a preparation method thereof. The waterborne polyurethane adhesive is prepared from the following raw material components in parts by mass through reaction: 50 to 75 parts of terephthalic acid type polyester polyol, 5 to 15 parts of phthalic anhydride type polyester polyol, 0.01 to 0.06 part of a catalyst, 8 to 24 parts of isocyanate, 55 to 110 parts of acetone, 2 to 3 parts of a hydrophilic chain extender, 60 to 120 parts of deionized water, 0.2 to 0.5 part of a neutralizing agent, 0.03 to 0.05 part of a de-foaming agent, 0.03 to 0.08 part of a flatting agent and 0.3 to 0.5 part of a thickening agent. And 0.2 to 0.5 part of a diamine chain extender. The waterborne polyurethane adhesive disclosed by the invention has excellent heat resistance, initial viscosity and ductility, can be used for bonding materials of different base materials, and is particularly suitable for the field of adhesives in a high-temperature environment.

Description

Technical Field

[0001] The invention relates to the technical field of waterborne polyurethane adhesives, and in particular to a waterborne polyurethane adhesive with high heat resistance, high initial adhesion and high ductility and a preparation method thereof. Background Art

[0002] The development of environmentally friendly water-based polyurethane adhesives is an inevitable trend, but many water-based polyurethane adhesives currently still have problems such as low initial adhesion and poor heat resistance. Although some existing technologies can improve the heat resistance of water-based polyurethane adhesives to a certain extent, they will inevitably greatly reduce the ductility of water-based polyurethane adhesives, that is, the existing technologies generally have the problem of not being able to balance heat resistance and ductility.

[0003] The patent specification with announcement number CN104004486B discloses the use of three polyester diols of high crystallinity, namely poly(hexane adipate), poly(neopentyl glycol sebacate) and poly(butylene terephthalate), as soft segments, and the addition of siloxane coupling agent, talcum powder, titanium dioxide and fumed silica to improve the initial tack and heat resistance of waterborne polyurethane adhesive. The initial tack is above 28 N / cm (2.8 N / mm) and can generally be as high as 28-43 N / cm (2.8-4.3 N / mm). The added components and processes are relatively complicated.

[0004] The patent specification with publication number CN111334238A discloses the use of alcoholysis of PET to prepare aromatic polyester polyols, which are mixed with polyether polyols and reacted with isocyanates to introduce the rigid structure of the benzene ring group into the urethane prepolymer, so that it has a higher thermal activation temperature and good high-temperature performance. However, the polyester polyol and the polyether polyol have poor compatibility, and the prepared water-based polyurethane will phase separate, which is more serious under high temperature environment.

[0005] The patent specification with announcement number CN109401716B discloses a method for preparing a fast-crystallizing water-based polyurethane adhesive. By adjusting the structure of the polyurethane itself and using the hard segment in the polyurethane molecular chain as the crystal nucleus, crystallization is induced during the cooling process of the polyurethane, thereby increasing the initial crystallinity of the polyurethane adhesive and thus increasing the initial bonding strength of the adhesive. Its heat resistance is not involved. Summary of the invention

[0006] The present invention provides a water-based polyurethane adhesive with high heat resistance, high initial adhesion and high ductility and a preparation method thereof. The water-based polyurethane adhesive has excellent heat resistance, initial adhesion and ductility, can bond materials of different substrates, and is particularly suitable for the adhesive field in high temperature environments.

[0007] [1] A water-based polyurethane adhesive with high heat resistance, high initial adhesion and high ductility, obtained by reacting the following raw material components in parts by weight: 50-75 parts of terephthalic acid type polyester polyol, 5-15 parts of phthalic anhydride type polyester polyol, 0.01-0.06 parts of catalyst, 8-24 parts of isocyanate, 55-110 parts of acetone, 2-3 parts of hydrophilic chain extender, 60-120 parts of deionized water, 0.2-0.5 parts of neutralizer, 0.03-0.05 parts of defoamer, 0.03-0.08 parts of leveling agent, 0.3-0.5 parts of thickener, and 0.2-0.5 parts of diamine chain extender;

[0008] The molecular weight of the terephthalic acid-based polyester polyol is 400-10000 g / mol, and the polyol is obtained by esterification and / or transesterification reaction and polymerization reaction of raw material components including a diol without side groups, a first aliphatic acid component and terephthalic acid, wherein the diol without side groups includes one or more of ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol, and the first aliphatic acid component includes one or more of succinic acid, glutaric acid, adipic acid, sebacic acid or its anhydride or ester compound; in the raw material components of the terephthalic acid-based polyester polyol, the molar ratio of terephthalic acid to the first aliphatic acid component is (8:2)-(6:4);

[0009] The molecular weight of the phthalic anhydride polyester polyol is 400-10000 g / mol, and the phthalic anhydride polyester polyol is obtained by esterification and / or transesterification reaction and polymerization reaction of raw material components including a pendant-type diol, a second aliphatic acid component and phthalic anhydride. The pendant-type diol includes one or more of 1,2-propylene glycol, 1,3-butanediol, neopentyl glycol, 2-methyl-1,3-propanediol, ethyl butyl propanediol and trimethylpentanediol. The second aliphatic acid component includes one or more of succinic acid, glutaric acid, adipic acid, sebacic acid or its anhydride or ester compound. In the raw material components of the phthalic anhydride polyester polyol, the molar ratio of phthalic anhydride to the second aliphatic acid component is (9:1)-(5:5), for example, 8:2.

[0010] Furthermore, the molecular weight of the terephthalic acid-based polyester polyol may be 1000-2000 g / mol, the acid value ≤1.5 mgKOH / g, the water content ≤300 ppm, the platinum cobalt color number ≤60, and the melting temperature 60-100°C.

[0011] Furthermore, the molecular weight of the phthalic anhydride polyester polyol may be 1000-2000 g / mol, the acid value ≤1.5 mgKOH / g, the water mass content ≤300 ppm, the platinum cobalt color number ≤60, and the glass transition temperature of -10 to 20°C, for example, -5°C, 0°C, 5°C, 10°C, 15°C, etc., preferably 15 to 20°C.

[0012] In the raw material components of the terephthalic acid-based polyester polyol, the molar ratio of the diol without side groups to the total acid component consisting of terephthalic acid and the first aliphatic acid component can be (1.02-1.5):1.

[0013] In the raw material components of the phthalic anhydride polyester polyol, the molar ratio of the total acid component consisting of the side-group diol, phthalic anhydride and the second aliphatic acid component can be (1.02-1.5):1.

[0014] The preparation method of the terephthalic acid-based polyester polyol may include: mixing a diol without side groups, a first aliphatic acid component and terephthalic acid, reacting at 150-250° C. for 1-10 hours under stirring conditions to complete esterification and / or ester exchange reaction; adding a first catalyst, evacuating the reaction mixture under stirring conditions for negative pressure distillation, controlling the reaction temperature at 150-260° C. until the molecular weight reaches the target molecular weight, stopping the reaction, and obtaining the terephthalic acid-based polyester polyol.

[0015] The preparation method of the phthalic anhydride polyester polyol may include: mixing a pendant diol, a second aliphatic acid component and phthalic anhydride, reacting at 150-250° C. for 1-10 hours under stirring conditions to complete esterification and / or ester exchange reaction; adding a second catalyst, vacuumizing the reaction mixture under stirring conditions for negative pressure distillation, controlling the reaction temperature at 150-260° C. until the molecular weight reaches the target molecular weight, stopping the reaction, and obtaining the phthalic anhydride polyester polyol.

[0016] The first catalyst and the second catalyst may independently include one or more of tetramethyl titanate, tetraethyl titanate, tetrapropyl titanate, tetraisopropyl titanate, and tetrabutyl titanate.

[0017] The isocyanate may include one or more of toluene diisocyanate, diphenylmethane diisocyanate, terephthalate, isophorone diisocyanate, cyclohexane-1,4-diisocyanate, dicyclohexylmethane-4,4-diisocyanate, xylylene diisocyanate, and hexamethylene diisocyanate.

[0018] In the raw material components of the water-based polyurethane adhesive with high heat resistance, high initial viscosity and high ductility, the catalyst may include one or more of dibutyltin dilaurate, stannous octoate, monobutyltin oxide and dibutyltin diacetate.

[0019] The hydrophilic chain extender may include one or more of dimethylol propionic acid DMPA, dimethylol butyric acid DMBA, and sodium ethylenediamine sulfonate AAS.

[0020] The neutralizing agent may include one or more of sodium hydroxide, potassium hydroxide, ammonia water, triethylamine, and N,N-dimethylethanolamine.

[0021] The defoaming agent may include one or more of BYK-011, BYK-012, BYK-022, BYK-035, BYK-037, and BYK-141.

[0022] The leveling agent may include one or more of RM-8W, HY-5030, and HY-5057.

[0023] The thickener may include one or more of L-75N, WT-105A, RM-995, and Rheovis AS1125.

[0024] The diamine chain extender may include one or more of ethylenediamine, diethylenetriamine, hexamethylenediamine, piperazine, and hydrazine hydrate.

[0025] [2] The method for preparing the water-based polyurethane adhesive with high heat resistance, high initial adhesion and high ductility according to [1] comprises:

[0026] After dehydration of terephthalic acid polyester polyol and phthalic anhydride polyester polyol, isocyanate and catalyst are added, and prepolymerization reaction is carried out at 70-90°C for 0.5-2h to obtain a prepolymer; after the prepolymer is cooled to 40-55°C, acetone and a hydrophilic chain extender are added, and the reaction is continued for 0.2-3h, and then deionized water is added for emulsification for 3-20min under high-speed stirring conditions, and then a neutralizer is added for emulsification for 3-15min under high-speed stirring conditions, and then a diamine chain extender is added, and the reaction is carried out for 5-30min under high-speed stirring conditions, and the solvent acetone is removed by vacuum at 40-60°C to prepare an aqueous polyurethane emulsion; a defoamer, a leveling agent and a thickener are added to the aqueous polyurethane emulsion, and the mixture is evenly mixed to obtain the aqueous polyurethane adhesive.

[0027] Furthermore, the terephthalic acid polyester polyol and the phthalic anhydride polyester polyol can be dehydrated at 100-120° C. and 10-1000 Pa for 1-4 hours before adding isocyanate and a catalyst.

[0028] In the preparation method described in [3], the stirring speed of the high-speed stirring can be 3500-6000rpm.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The initial adhesion of waterborne polyurethane adhesive is related to its crystallinity and degree of crystallinity. Terephthalic acid has high symmetry, and the prepared terephthalic acid-based polyester polyol has high regularity, thus having strong crystallinity, which can improve the initial adhesion performance of the adhesive.

[0031] Phthalic anhydride polyester polyols are prepared by using pendant diols to have a high glass transition temperature, which improves the initial adhesion of waterborne polyurethane adhesives by restricting the movement of molecular chains.

[0032] Both terephthalic acid polyester polyol and phthalic anhydride polyester polyol have a rigid benzene ring structure. By adjusting the ratio of their respective aliphatic acid components and aromatic dibasic acid components (terephthalic acid or phthalic anhydride), the two work together to improve the heat resistance of the waterborne polyurethane adhesive without affecting the ductility of the final waterborne polyurethane adhesive. The waterborne polyurethane adhesive has good ductility, the material has a strong ability to resist external impact, and the service life of the product is increased.

[0033] The phthalic anhydride polyester polyol prepared by using pendant diol has a high glass transition temperature. It will not affect the crystallization of terephthalic acid polyester polyol. On the contrary, it can act as a crystal nucleus in the polyurethane molecular chain, inducing the crystallization of terephthalic acid polyester polyol during the cooling process of polyurethane, thereby improving the crystallization rate and crystallinity of water-based polyurethane, thereby improving the bonding performance and heat resistance of water-based polyurethane adhesives.

[0034] The waterborne polyurethane adhesive of the invention has simple components, phthalic anhydride polyester polyol and terephthalic acid polyester polyol are both aromatic polyester polyols with good compatibility, easy processing and good product stability. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are only intended to illustrate the present invention and are not intended to limit the scope of the present invention. The operating methods in the following examples where no specific conditions are indicated are usually carried out under conventional conditions or under conditions recommended by the manufacturer.

[0036] Embodiment 1:

[0037] Mix 558.6g of ethylene glycol, 233.8g of adipic acid and 1063.2g of terephthalic acid raw materials, react at 200°C with stirring for 8h, add 0.18g of tetraethyl titanate, continue stirring and evacuate, control the temperature at 200°C, and stop evacuating when the hydroxyl value approaches 75mgKOH / g to obtain terephthalic acid type polyester polyol PP1500.

[0038] 608.8 g of 1,2-propylene glycol, 204.6 g of adipic acid and 829.4 g of phthalic anhydride raw materials were mixed, reacted at 200°C for 8 h under stirring conditions, 0.18 g of tetraethyl titanate was added, stirring was continued and vacuum was applied, the temperature was controlled at 200°C, and vacuum was stopped when the hydroxyl value was close to 75 mgKOH / g, thereby obtaining phthalic anhydride type polyester polyol PAP1500 with a glass transition temperature of 15°C.

[0039] 70.2g of polyol PP1500 and 7.8g of polyol PAP1500 were dehydrated at 110°C and 100Pa for 1h, 15g of isophorone diisocyanate and 0.02g of dibutyltin dilaurate were added, and prepolymerization reaction was carried out at 75°C for 1h to obtain a prepolymer; after the obtained prepolymer was cooled to 50°C, 93g of acetone and 3g of dimethylol propionic acid were added, and the reaction was continued for 0.5h, and then 110g of deionized water was added under high-speed stirring for emulsification for 10min, and then 0.5g of triethylamine was added. The amine was continuously emulsified under high-speed stirring conditions for 5 minutes, and then 0.3 g of ethylenediamine was added, and the mixture was reacted under high-speed stirring conditions for 10 minutes. The solvent acetone was removed by vacuum at 50°C to prepare an aqueous polyurethane emulsion. 0.03 g of defoamer BYK-011, 0.04 g of leveling agent RM-8W, and 0.35 g of thickener WT-105A were added to the aqueous polyurethane emulsion and mixed evenly to prepare an aqueous polyurethane adhesive with high heat resistance, high initial viscosity, and high ductility. The specific performance test results are shown in Table 1.

[0040] Comparative Example 1:

[0041] Referring to Example 1, phthalic anhydride polyester polyol PAP1500 was prepared.

[0042] A waterborne polyurethane adhesive was prepared with reference to Example 1, except that 78 g of polyol PAP1500 was used to replace 70.2 g of polyol PP1500 and 7.8 g of polyol PAP1500 in Example 1, and the rest was the same. The specific performance test results of the obtained waterborne polyurethane adhesive are shown in Table 1.

[0043] Comparative Example 2:

[0044] Referring to Example 1, terephthalic acid-based polyester polyol PP1500 was prepared.

[0045] A waterborne polyurethane adhesive was prepared with reference to Example 1, except that 78 g of polyol PP1500 was used to replace 70.2 g of polyol PP1500 and 7.8 g of polyol PAP1500 in Example 1, and the rest was the same. The specific performance test results of the obtained waterborne polyurethane adhesive are shown in Table 1.

[0046] Comparative Example 3:

[0047] 558.6 g of ethylene glycol, 818.4 g of adipic acid and 398.7 g of terephthalic acid (the molar ratio of terephthalic acid to adipic acid is 3:7) were mixed, reacted at 200 ° C for 8 h under stirring conditions, 0.18 g of tetraethyl titanate was added, stirring was continued and vacuum was applied, and the temperature was controlled at 200 ° C until the hydroxyl value was close to 75 mgKOH / g, then vacuum was stopped to obtain terephthalic acid type polyester polyol P1500.

[0048] 608.8 g of 1,2-propylene glycol, 716.1 g of adipic acid and 311 g of phthalic anhydride (phthalic anhydride and adipic acid molar ratio is 3:7) were mixed, reacted at 200°C for 8 h under stirring conditions, 0.18 g of tetraethyl titanate was added, stirring was continued and vacuum was applied, the temperature was controlled at 200°C, and vacuum was stopped when the hydroxyl value was close to 75 mgKOH / g, thereby obtaining phthalic anhydride type polyester polyol A1500 with a glass transition temperature of -25°C.

[0049] A waterborne polyurethane adhesive was prepared with reference to Example 1, except that 70.2 g of polyol P1500 was used to replace 70.2 g of polyol PP1500 in Example 1, and 7.8 g of polyol A1500 was used to replace polyol PAP1500 in Example 1, and the rest was the same. The specific performance test results of the obtained waterborne polyurethane adhesive are shown in Table 1.

[0050] Comparative Example 4:

[0051] Referring to Example 1, terephthalic acid-based polyester polyol PP1500 was prepared.

[0052] Refer to Comparative Example 3 to prepare phthalic anhydride type polyester polyol A1500.

[0053] A waterborne polyurethane adhesive was prepared with reference to Example 1, except that 7.8 g of polyol A1500 was used to replace the polyol PAP1500 in Example 1, and the rest was the same. The specific performance test results of the obtained waterborne polyurethane adhesive are shown in Table 1.

[0054] Comparative Example 5:

[0055] Refer to Comparative Example 3 to prepare terephthalic acid-based polyester polyol P1500.

[0056] Referring to Example 1, phthalic anhydride polyester polyol PAP1500 was prepared.

[0057] The waterborne polyurethane adhesive was prepared with reference to Example 1, except that 70.2 g of polyol P1500 was used to replace 70.2 g of polyol PP1500 in Example 1, and the rest was the same. The specific performance test results of the obtained waterborne polyurethane adhesive are shown in Table 1.

[0058] Table 1

[0059]

[0060] in:

[0061] The stability test of the emulsion refers to the "Waterborne Polyurethane Materials" edited by Xu Gewen. The storage stability is simulated by a centrifugal accelerated sedimentation test. Usually, after centrifugation at 3000 rpm for 15 minutes, if there is no precipitation, it can be considered to have a storage stability period of 6 months.

[0062] The solid content determination refers to GB / T 1725-2007 "Paints, varnishes and plastics - Determination of non-volatile matter content".

[0063] The initial adhesion refers to GB / T 2791-1995 "Test method for T peel strength of adhesives", where the initial adhesion is tested 2 minutes after the sample is prepared and bonded.

[0064] The heat resistance test is carried out by placing the sample at room temperature for 24 hours, and then testing the length of the PVC soft leather stretched within 10 minutes under a load of 1 kg in different ambient temperatures.

[0065] The emulsions of the embodiment and the comparative example were poured onto a tetrafluoroethylene plate to form a film, and then placed at 25°C for one week. After the water evaporated slowly, the film was placed in a vacuum oven and dried at 60°C for 2 days to obtain a polyurethane gel film with a thickness of about 100 microns. The film-formed sample was made into a dumbbell-shaped strip, and the material was tested for stress-strain curve according to the test method for tensile properties of plastics GB / T1040-92 to obtain the elongation at break.

[0066] Comparative Example 1 was compared with Example 1, and the test results showed that the waterborne polyurethane adhesive prepared using only phthalic anhydride polyester polyol had poor heat resistance and low initial viscosity, which was not as good as the waterborne polyurethane adhesive prepared by the present invention.

[0067] Comparative Example 2 is compared with Comparative Example 1. The test results show that the waterborne polyurethane adhesive prepared by using only terephthalic acid polyester polyol has improved heat resistance and initial adhesion compared with the waterborne polyurethane adhesive prepared by using only phthalic anhydride polyester polyol in Comparative Example 1, but the ductility (elongation at break) is significantly reduced. Further comparing Comparative Examples 1-2 with Example 1, it can be found that the present invention uses terephthalic acid polyester polyol and phthalic anhydride polyester polyol at the same time and adjusts the amount of the two, which produces an unexpected synergistic effect. The obtained waterborne polyurethane adhesive has significantly improved heat resistance and initial adhesion, and also has excellent ductility (elongation at break).

[0068] Comparative Examples 3-5 are compared with Example 1. The test results show that the molar ratio of terephthalic acid to the first aliphatic acid component of the terephthalic acid-type polyester polyol is not within the range of (8:2)-(6:4) required by the present invention, and the molar ratio of phthalic anhydride to the second aliphatic acid component of the phthalic anhydride-type polyester polyol is not within the range of (9:1)-(5:5). The heat resistance and initial adhesion of the prepared water-based polyurethane adhesive do not reach the level of the water-based polyurethane of the present invention, which reflects the important role of the specific molar ratio of the acid components in the terephthalic acid-type polyester polyol and the phthalic anhydride-type polyester polyol of the present invention in the heat resistance and initial adhesion of the water-based polyurethane adhesive.

[0069] In addition, it should be understood that after reading the above description of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. A water-based polyurethane adhesive with high heat resistance, high initial viscosity and high ductility, characterized in that: The method is obtained by reacting the following raw material components in parts by weight: 50-75 parts of terephthalic acid polyester polyol, 5-15 parts of phthalic anhydride polyester polyol, 0.01-0.06 parts of catalyst, 8-24 parts of isocyanate, 55-110 parts of acetone, 2-3 parts of hydrophilic chain extender, 60-120 parts of deionized water, 0.2-0.5 parts of neutralizer, 0.03-0.05 parts of defoamer, 0.03-0.08 parts of leveling agent, 0.3-0.5 parts of thickener and 0.2-0.5 parts of diamine chain extender; The molecular weight of the terephthalic acid-based polyester polyol is 400-10000 g / mol, and the polyol is obtained by esterification and / or transesterification reaction and polymerization reaction of raw material components including a diol without side groups, a first aliphatic acid component and terephthalic acid, wherein the diol without side groups includes one or more of ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol, and the first aliphatic acid component includes one or more of succinic acid, glutaric acid, adipic acid, sebacic acid or its anhydride or ester compound; in the raw material components of the terephthalic acid-based polyester polyol, the molar ratio of terephthalic acid to the first aliphatic acid component is (8:2)-(6:4); The molecular weight of the phthalic anhydride polyester polyol is 400-10000 g / mol, and the phthalic anhydride polyester polyol is obtained by esterification and / or transesterification reaction and polymerization reaction of raw material components including a pendant-type diol, a second aliphatic acid component and phthalic anhydride. The pendant-type diol includes one or more of 1,2-propylene glycol, 1,3-butanediol, neopentyl glycol, 2-methyl-1,3-propanediol, ethyl butyl propanediol and trimethylpentanediol. The second aliphatic acid component includes one or more of succinic acid, glutaric acid, adipic acid, sebacic acid or its anhydride or ester compound. In the raw material components of the phthalic anhydride polyester polyol, the molar ratio of phthalic anhydride to the second aliphatic acid component is (9:1)-(5:5).

2. The water-based polyurethane adhesive with high heat resistance, high initial viscosity and high ductility according to claim 1, characterized in that: The molecular weight of the terephthalic acid polyester polyol is 1000-2000 g / mol, the acid value is ≤1.5 mgKOH / g, the water content is ≤300 ppm, the platinum cobalt color number is ≤60, and the melting temperature is 60-100°C.

3. The water-based polyurethane adhesive with high heat resistance, high initial viscosity and high ductility according to claim 1, characterized in that: The phthalic anhydride polyester polyol has a molecular weight of 1000-2000 g / mol, an acid value of ≤1.5 mgKOH / g, a water content of ≤300 ppm, a platinum cobalt color number of ≤60, and a glass transition temperature of -10 to 20°C, preferably 15 to 20°C.

4. The water-based polyurethane adhesive with high heat resistance, high initial viscosity and high ductility according to claim 1, characterized in that: In the raw material components of the terephthalic acid-based polyester polyol, the molar ratio of the diol without side groups to the total acid component consisting of terephthalic acid and the first aliphatic acid component is (1.02-1.5):

1.

5. The water-based polyurethane adhesive with high heat resistance, high initial viscosity and high ductility according to claim 1, characterized in that: In the raw material components of the phthalic anhydride polyester polyol, the molar ratio of the total acid component consisting of the side-group diol, phthalic anhydride and the second aliphatic acid component is (1.02-1.5):

1.

6. The water-based polyurethane adhesive with high heat resistance, high initial viscosity and high ductility according to claim 1, characterized in that: The preparation method of the terephthalic acid type polyester polyol comprises: mixing a side-free diol, a first aliphatic acid component and terephthalic acid, reacting at 150-250° C. for 1-10 hours under stirring conditions to complete esterification and / or transesterification reaction; adding a first catalyst, vacuumizing the reaction mixture under stirring conditions for negative pressure distillation, controlling the reaction temperature at 150-260° C. until the molecular weight reaches the target molecular weight, stopping the reaction, and obtaining the terephthalic acid type polyester polyol; The preparation method of the phthalic anhydride polyester polyol comprises: mixing a diol having a side group, a second aliphatic acid component and phthalic anhydride, reacting at 150-250° C. for 1-10 hours under stirring conditions to complete esterification and / or transesterification reaction; adding a second catalyst, vacuumizing the reaction mixture under stirring conditions for negative pressure distillation, controlling the reaction temperature at 150-260° C. until the molecular weight reaches the target molecular weight, stopping the reaction, and obtaining the phthalic anhydride polyester polyol; The first catalyst and the second catalyst independently include one or more of tetramethyl titanate, tetraethyl titanate, tetrapropyl titanate, tetraisopropyl titanate, and tetrabutyl titanate.

7. The water-based polyurethane adhesive with high heat resistance, high initial viscosity and high ductility according to claim 1, characterized in that: The isocyanate includes one or more of toluene diisocyanate, diphenylmethane diisocyanate, terephthalate, isophorone diisocyanate, cyclohexane-1,4-diisocyanate, dicyclohexylmethane-4,4-diisocyanate, xylylene diisocyanate and hexamethylene diisocyanate.

8. The water-based polyurethane adhesive with high heat resistance, high initial viscosity and high ductility according to claim 1, characterized in that: The catalyst includes one or more of dibutyltin dilaurate, stannous octoate, monobutyltin oxide, and dibutyltin diacetate; The hydrophilic chain extender includes one or more of dimethylol propionic acid DMPA, dimethylol butyric acid DMBA, and sodium ethylenediamine sulfonate AAS; The neutralizing agent includes one or more of sodium hydroxide, potassium hydroxide, ammonia water, triethylamine, and N,N-dimethylethanolamine; The defoamer includes one or more of BYK-011, BYK-012, BYK-022, BYK-035, BYK-037, and BYK-141; The leveling agent includes one or more of RM-8W, HY-5030, and HY-5057; The thickener includes one or more of L-75N, WT-105A, RM-995, and Rheovis AS1125; The diamine chain extender includes one or more of ethylenediamine, diethylenetriamine, hexamethylenediamine, piperazine and hydrazine hydrate.

9. The method for preparing the water-based polyurethane adhesive with high heat resistance, high initial viscosity and high ductility according to any one of claims 1 to 8, characterized in that: include: After dehydration of terephthalic acid polyester polyol and phthalic anhydride polyester polyol, isocyanate and catalyst are added, and prepolymerization reaction is carried out at 70-90°C for 0.5-2h to obtain a prepolymer; after the prepolymer is cooled to 40-55°C, acetone and a hydrophilic chain extender are added, and the reaction is continued for 0.2-3h, and then deionized water is added for emulsification for 3-20min under high-speed stirring conditions, and then a neutralizer is added for emulsification for 3-15min under high-speed stirring conditions, and then a diamine chain extender is added, and the reaction is carried out for 5-30min under high-speed stirring conditions, and the solvent acetone is removed by vacuum at 40-60°C to prepare an aqueous polyurethane emulsion; a defoamer, a leveling agent and a thickener are added to the aqueous polyurethane emulsion, and the mixture is evenly mixed to obtain the aqueous polyurethane adhesive.

10. The preparation method according to claim 9, characterized in that: After dehydrating terephthalic acid polyester polyol and phthalic anhydride polyester polyol at 100-120°C and 10-1000Pa for 1-4h, isocyanate and catalyst are added; The stirring speed of the high-speed stirring is 3500-6000 rpm.

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