Waterborne alkyd resin as well as preparation method and application thereof

Abstract

The invention relates to the field of water-soluble resin, and discloses water-based alkyd resin as well as a preparation method and application thereof. The water-soluble resin disclosed by the invention is prepared from 20 to 24 parts of erythritol, 6 to 8 parts of isosorbide, 10 to 15 parts of neodecanoic acid, 15 to 20 parts of succinic acid, 15 to 20 parts of sebacic acid, 2 to 3 parts of citric acid, 5 to 7 parts of isophorone diamine, 9 to 10 parts of linolenic acid propylene glycol ester and a catalyst. Under the condition that an emulsifier, a cosolvent and a large amount of neutralizer are not added, the emulsion can rapidly form a uniform milky-white dispersion with the same amount as water, and the emulsion is free of flocculation, layering and precipitation after standing at 25 DEG C for 30 days. Technological parameters are simple and controllable, the system is low in foam and easy to defoam, and large-scale amplification is facilitated; meanwhile, the dosage of a cosolvent and a neutralizer is reduced, VOC and odor are reduced, and the water-based environment-friendly requirement is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of water-soluble resin, more particularly, to a waterborne alkyd resin and its preparation method and application. BACKGROUND

[0002] Traditional alkyd resins are mostly dispersed in organic solvents, which release a large amount of volatile organic compounds during production and use, and do not meet the current increasingly stringent environmental regulations and green manufacturing requirements. The water-based alkyd resin has become the mainstream direction of research and industrial development. Among them, the self-emulsifying salt formation method introduces carboxyl and other acidic groups into the main chain, and uses triethanolamine, diethanolamine and other alkaline neutralizing agents to form salt to achieve water dispersion. Because it does not depend on external emulsifiers and has a simple process, it is widely used in the preparation of water-based alkyd resins.

[0003] However, the existing self-emulsifying salt formation method of water-based alkyd resin still has many deficiencies in emulsion stability, structure design and process control. Patent CN1580093A improves the emulsion dispersibility by introducing polyethylene glycol hydrophilic segments, but the hydrophilic structure is connected to the main chain by ester bonds, which is prone to hydrolysis reaction in water-based environment, thereby causing problems such as increase in emulsion particle size, system layering, and decrease in storage stability. Patent CN108727952A uses polyether alcohol monomers and plant oil acid to copolymerize to construct an amphiphilic structure, so that the resin can be self-emulsified by neutralization, but the system still needs to rely on a certain proportion of organic cosolvents to control the reaction viscosity and emulsification behavior, and the hydrophilic structure mainly uses non-reactive ether chains, which still faces degradation risk under acidic, alkaline or oxidative conditions.

[0004] In addition, the current commonly used biological oil raw materials such as cashew nut shell oil, tung oil, and castor oil as hydrophobic chain segments, such as the water-based alkyd resin system disclosed by Luoteng et al., although they have renewability and certain flexibility control ability, but the raw material structure usually contains phenolic hydroxyl or polyunsaturated double bonds, which is easy to crosslink, oxidize or react in high-temperature polycondensation reaction, increasing the difficulty of viscosity control and the risk of gelation, limiting the reaction window and operability. At the same time, due to the uneven distribution of functional group types and positions of oil raw materials, some samples have water separation or layering phenomenon, and the storage stability still needs to be improved.

[0005] Therefore, the existing water-based alkyd resin prepared by the self-emulsifying salt formation method generally faces problems such as poor emulsification stability, complex reaction system, uncontrollable raw material structure, and the need to add organic cosolvents. Especially in the absence of effective molecular structure design, the balance between hydrophilic and hydrophobic of resin molecules is difficult to accurately adjust, resulting in insufficient self-emulsification ability of the system, and easy to appear unstable phenomena such as layering and flocculation. At the same time, in order to improve the dispersibility or reduce the reaction viscosity, alcohol or ether cosolvents are often added, which increases VOC, which is not conducive to the environment and health and safety. SUMMARY

[0006] The present application provides a water-based alkyd resin to overcome the problems of poor dispersibility, high VOC content and low emulsion stability caused by the addition of emulsifiers, cosolvents and a large amount of neutralizing agents in the prior art;

[0007] Another object of the present application is to provide a preparation method of the water-based alkyd resin.

[0008] Another object of the present application is to provide an application of the water-based alkyd resin.

[0009] To solve the above technical problems, the technical scheme of the present application is as follows:

[0010] A water-based alkyd resin, comprising 20-24 parts of erythritol, 6-8 parts of isosorbide, 10-15 parts of neodecanoic acid, 15-20 parts of succinic acid, 15-20 parts of sebacic acid, 2-3 parts of citric acid, 5-7 parts of isophorone diamine, 9-10 parts of linolenic acid propylene glycol ester, and a catalyst.

[0011] Due to the unique furan bicyclic structure and two secondary hydroxyl sites of isosorbide, it can provide moderate reactivity in the esterification process, while giving the product higher molecular regularity and thermal stability, significantly improving the storage stability and film flexibility of the emulsion.

[0012] Preferably, the catalyst is 0.5-0.7 parts, which is a compounded system of p-toluenesulfonic acid and dibutyl tin acid ester with a mass ratio of 5:1.

[0013] Further, the mass ratio of erythritol to isosorbide is 2.5-4:1.

[0014] Further, the mass ratio of succinic acid to sebacic acid is 0.75-1.5:1.

[0015] Preferably, the mass ratio of succinic acid to sebacic acid is 1:1.

[0016] By compounding succinic acid and sebacic acid as the binary acid component, the water-based alkyd resin has good reactivity and esterification rate, and also considers the molecular chain flexibility and emulsion stability, improving the comprehensive performance of the product.

[0017] Further, the linolenic acid propylene glycol ester accounts for 9%-11% of the total solid content of the alkyd resin.

[0018] Preferably, the linolenic acid propylene glycol ester accounts for 10% of the total solid content of the alkyd resin.

[0019] Further, the citric acid accounts for 3.5%-6.5% of the total mass of neodecanoic acid, succinic acid, sebacic acid and citric acid.

[0020] A preparation method of the water-based alkyd resin comprises the following steps: firstly melting erythritol and isosorbide, adding succinic acid and sebacic acid, then adding neodecanoic acid and a catalyst, heating, and finally adding citric acid and continuously heating; cooling, adding linolenic acid propylene glycol ester and continuously reacting; further cooling, adding isophorone diamine in two stages; and dispersing to obtain the water-based alkyd resin.

[0021] Preferably, the erythritol and isosorbide are melted at 110-130 DEG C under a nitrogen atmosphere.

[0022] Further, when the temperature is heated to 150-170 DEG C and the acid value is reduced to 60-80 mgKOH / g, citric acid is added; continuously heating to 190-200 DEG C to perform esterification reaction, and the reaction is performed until the acid value is reduced to below 30 mgKOH / g.

[0023] Further, the temperature is cooled to 140-155 DEG C, and linolenic acid propylene glycol ester is added to continuously react for 20-40 minutes.

[0024] Preferably, the linolenic acid propylene glycol ester contains 0.1% of butylated hydroxytoluene (BHT).

[0025] Further, when the temperature is cooled to 110-130 DEG C, 8%-12% of the total amount of isophorone diamine is added to reduce the acid value by 3-8 mgKOH / g; the remaining isophorone diamine is added under the condition that the water phase exists and the temperature is not higher than 90 DEG C, and is dispersed for 20-40 minutes.

[0026] Preferably, before the remaining isophorone diamine is added, it is pre-diluted with water in an amount of 1-2 times the mass of the isophorone diamine.

[0027] Preferably, after the dispersion is completed, the solid content is 45-55 wt%.

[0028] The water-based alkyd resin is used for preparing an adhesive or a coating.

[0029] The present application first forms covalent grafting sites along the main chain by slightly amidating a small amount of isophorone diamine with carboxyl groups, and then adds the remaining amine by pre-dilution and in stages to complete mild amine salification and phase transition. The first stage only causes a small decrease in acid value and a weak amide signal, which ensures that the neutralizable sites are sufficient. The low temperature and staged addition of the second stage inhibit continuous amidation and bridging, thereby avoiding late thickening and microgelation from the source. This time sequence of grafting before salification establishes a stable surface charge and hydration shell without relying on additional emulsifiers, cosolvents or a large amount of neutralizing agents, and is conducive to reducing the VOC of the system.

[0030] The present application constructs a hydrated and rigid-flexible adapted polyol segment by erythritol and isosorbide; succinic acid and sebacic acid provide the polarity gradient and flexibility of aliphatic diacid; neodecanoic acid and trace citric acid introduce moderate branching to inhibit dense packing without excessive crosslinking. The polarity distribution is thus limited in the window of neither loose nor gel, which cooperates with the prior grafting and post-salting path to form a new phase dispersion control mode, producing comprehensive technical effects beyond the conventional one-time neutralization or additional emulsifier route.

[0031] Compared with the prior art, the beneficial effects of the technical scheme of the present application are:

[0032] The present application can quickly form a uniform milky white dispersion with water under the condition of no additional emulsifier, cosolvent and large amount of neutralizer, and the appearance is fine immediately after discharging, and there is no flocculation, no stratification and no precipitation after standing for 30 days at 25℃. Compared with one-time neutralization or full high temperature one-step method, this path effectively inhibits continuous amidation and interchain bridging, significantly reduces the risk of delayed thickening, stringing, fisheye and microgel. The present application cooperates the polarity gradient and moderate branching of the formula to ensure that stable dispersion is still obtained in the range of 45% to 55% solid content. The process parameters are simple and controllable, the system is low-foaming and easy to defoam, and it is convenient for scale-up; at the same time, the amount of cosolvent and neutralizer is reduced, which is beneficial to reduce VOC and odor, and meets the water-based environmental protection demand. DETAILED DESCRIPTION

[0033] The present application will be further described below in conjunction with specific examples, but the examples do not make any form of limitation to the present application. Unless otherwise specified, the reagents, methods and equipment used in the present application are conventional reagents, methods and equipment in the technical field.

[0034] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0035] The catalyst is a compounded system of p-toluenesulfonic acid and dibutyl tin acid ester with a mass ratio of 5:1.

[0036] Example 1

[0037] Under nitrogen atmosphere, 20 parts of erythritol and 6 parts of isosorbide were melted at 110°C. Succinic acid 18 parts, sebacic acid 18 parts, and neodecanoic acid 15 parts were added, and a catalyst 0.5 parts was added. Under nitrogen protection, heated to 150°C, and the acid value was reduced to 60 mgKOH / g, citric acid 2 parts was added. Heated to 190°C, and the reaction was carried out until the acid value was reduced to below 30 mgKOH / g. The temperature was lowered to 145°C, and linolenic acid propylene glycol ester 10 parts was added, and the reaction was continued for 30 minutes. When the temperature was lowered to 110°C, 8% of the total amount of isophorone diamine (7 parts) was added, and the acid value was reduced by 3 mgKOH / g (about 8 minutes); the remaining isophorone diamine was pre-diluted with 1-fold water at no more than 90°C, and dispersed for 20 minutes. An aqueous alkyd resin dispersion was obtained, with a solid content of 45%.

[0038] Example 2

[0039] Under nitrogen atmosphere, 20 parts of erythritol and 6 parts of isosorbide were melted at 120°C. Succinic acid 15 parts, sebacic acid 20 parts, and neodecanoic acid 13 parts were added, and a catalyst 0.5 parts was added. Under nitrogen protection, heated to 165°C, and the acid value was reduced to 70 mgKOH / g, citric acid 2 parts was added. Heated to 190°C, and the reaction was carried out until the acid value was reduced to below 30 mgKOH / g. The temperature was lowered to 140°C, and linolenic acid propylene glycol ester 9 parts was added, and the reaction was continued for 20 minutes. When the temperature was lowered to 120°C, 10% of the total amount of isophorone diamine (6 parts) was added, and the acid value was reduced by 5 mgKOH / g (12 minutes); the remaining isophorone diamine was pre-diluted with 1.5-fold water at no more than 90°C, and dispersed for 30 minutes. An aqueous alkyd resin dispersion was obtained, with a solid content of 40%.

[0040] Example 3

[0041] Under nitrogen atmosphere, 22 parts of erythritol and 8 parts of isosorbide were melted at 130°C. Succinic acid 20 parts, sebacic acid 15 parts, and neodecanoic acid 10 parts were added, and a catalyst 0.7 parts was added. Under nitrogen protection, heated to 170°C, and the acid value was reduced to 80 mgKOH / g, citric acid 3 parts was added. Heated to 200°C, and the reaction was carried out until the acid value was reduced to below 30 mgKOH / g. The temperature was lowered to 155°C, and linolenic acid propylene glycol ester 10 parts was added, and the reaction was continued for 40 minutes. When the temperature was lowered to 130°C, 12% of the total amount of isophorone diamine (6 parts) was added, and the acid value was reduced by 8 mgKOH / g (not more than 20 minutes); the remaining isophorone diamine was pre-diluted with 2-fold water at no more than 90°C, and dispersed for 40 minutes. An aqueous alkyd resin dispersion was obtained, with a solid content of 50%.

[0042] Example 4

[0043] Under nitrogen atmosphere, 24 parts of erythritol was melted with 6 parts of isosorbide at 125°C. Succinic acid 18 parts, sebacic acid 18 parts, neodecanoic acid 12 parts and catalyst 0.7 parts were added. Under nitrogen protection, heated to 160°C, and the acid value was reduced to 65 mgKOH / g, citric acid 3 parts was added. Heated to 200°C, and the reaction was carried out until the acid value was reduced to 30 mgKOH / g or less. When the temperature was lowered to 155°C, 10% of the total amount of isophorone diamine (5 parts) was added, and the acid value was reduced by 6 mgKOH / g (10 min); the remaining isophorone diamine was pre-diluted with 1.5 times water at no more than 90°C, and dispersed for 25 min. An aqueous alkyd resin dispersion was obtained, with a solid content of 40%.

[0044] Comparative Example 1

[0045] Comparative Example 1 is similar to Example 1, except that all the isophorone diamine (pre-diluted with 1 times water) was added at once at no more than 90°C, and dispersed for 20 min.

[0046] Comparative Example 2

[0047] Comparative Example 2 is similar to Example 1, except that all the isophorone diamine was added at once at 120°C, and held for 20 min, then lowered to no more than 90°C for water dispersion.

[0048] Comparative Example 3

[0049] Comparative Example 3 is similar to Example 1, except that when the temperature was lowered to 110°C, 5% of the total amount of isophorone diamine (7 parts) was added.

[0050] Comparative Example 4

[0051] Comparative Example 4 is similar to Example 1, except that when the temperature was lowered to 110°C, 20% of the total amount of isophorone diamine (7 parts) was added.

[0052] Comparative Example 5

[0053] Comparative Example 5 is similar to Example 1, except that when the temperature was lowered to 105°C, the remaining isophorone diamine (pre-diluted with 1 times water) was added.

[0054] Comparative Example 6

[0055] Comparative Example 6 is similar to Example 1, except that after the linolenic acid propylene glycol ester reaction was completed, the temperature was lowered to 90°C, and an equal amount of triethanolamine (pre-mixed with an equal amount of water) was added at once, and dispersed for 30 min.

[0056] Comparative Example 7

[0057] Comparative Example 7 The technical solution is similar to that of Example 1, except that succinic acid is replaced by an equivalent amount of sebacic acid.

[0058] Comparative Example 8

[0059] Comparative Example 8 The technical solution is similar to that of Example 1, except that isosorbide is replaced by an equivalent amount of ethylene glycol.

[0060] Comparative Example 9

[0061] Comparative Example 9 The technical solution is similar to that of Example 1, except that erythritol 18 parts, isosorbide 4 parts, neodecanoic acid 28 parts, succinic acid 20 parts, sebacic acid 20 parts, and citric acid 6 parts.

[0062] Comparative Example 10

[0063] Comparative Example 10 The technical solution is similar to that of Example 1, except that erythritol 10 parts, neodecanoic acid 30 parts, and citric acid 1 part; and linolenic acid propylene glycol ester 15 parts.

[0064] Detection method

[0065] 1. Water-based performance test

[0066] The sample is mixed with deionized water in an equal mass ratio, and the appearance and layering of the emulsion are observed to investigate its water dispersion compatibility and stability.

[0067] 2. Storage stability test

[0068] The sample is placed at 25°C for 30 days, and whether flocculation, layering, precipitation, or rancidity occurs is observed.

[0069] Analysis description

[0070] 1. Appearance after preparation

[0071] According to the results of Table 1, the isophorone diamine of the embodiment is added in two stages: the first stage is to form sparse and uniform covalent grafting sites by amidation of part of the carboxyl groups; the second stage is to neutralize and coat in a low-temperature aqueous phase in sections, so that the chargeable sites are uniformly distributed and the interfacial tension is smoothly reduced, and the particles are sequentially generated and controlled to grow, so that a fine and stable dispersion structure is obtained at the end of preparation and lays a foundation for subsequent storage stability. Comparative Example 1 shows that omitting the first stage will cause partial neutralization and short-range coalescence; Comparative Example 2 shows that one-step reaction at high temperature is easy to cause inter-chain bridging and micro-gelation; Comparative Example 3 shows that there are not enough covalent grafting sites to stably bind the particle surface; Comparative Example 4 is easy to cause excessive bridging and thixotropic abnormalities; Comparative Example 5 shows that increasing the temperature of the second stage will weaken the surface charge and cause delayed agglomeration; Comparative Example 6 shows that using only tertiary amines to form salts lacks structural anchoring, and the long-term stability is insufficient; Comparative Examples 7 and 8 show that the polarity gradient and rigid-flexible matching of the system are destroyed, and the self-dispersing ability decreases; Comparative Examples 9 and 10 break the balance of moderate branching of the system, respectively leading to micro-gelation or insufficient interfacial membrane strength.

[0072] Table 1 Appearance state

[0073] Appearance after standing at 25°C for 10 minutes Example 1 Uniform, fine, milky white, no visible particles / fish eyes, little foam and easily dissipating Example 2 Uniform, milky white; no supernatant / particles, foam dissipates on its own Example 3 Compact, milky white, flow is continuous, no gel point; slightly thixotropic feel Example 4 Uniform, milky white, no visible particles; little foam dissipates naturally Comparative Example 1 Milky white is coarse, with a distinct haze; visible fine particles or very thin supernatant ring Comparative Example 2 Poor milky white, stringy, tacky; occasional microgel / fish eye Comparative Example 3 Emulsifiable but with poor fineness; occasional floating fine floc Comparative Example 4 Thick, heavy milky white, with slight stringiness or local microfloc Comparative Example 5 Surface appearance is acceptable; occasional very fine particles on close observation, with a slightly wall-hanging feel Comparative Example 6 Initial emulsification is acceptable but foam is retained; unclear boundaries, occasional sheen Comparative Example 7 Coarse milky white, with decreased uniformity; initial dispersion time is longer Comparative Example 8 Emulsifiable but with average fineness; occasional soft floc / micro particles Comparative Example 9 Thick milky white, stringy; visible microgel / fish eye Comparative Example 10 Loose milky white; low interfacial tension, with slight sheen / return oil point

[0074] 2, Water-based performance test

[0075] As can be seen from Table 2, the embodiment can be quickly and completely miscible, and the emulsion appearance is fine. Comparative Example 1 omits the first stage of isophorone diamine addition, and the subsequent neutralization is more concentrated in the local area, which is easy to cause short-range coalescence and coarse emulsion, and thin supernatant is often seen at the edge. Comparative Example 2 consumes the neutralizable carboxyl groups and enhances inter-chain bridging by high-temperature continuous amidation, and shows adhesion and micro-gelation after water is added, which is difficult to miscible. Comparative Example 3 has weak surface binding force, and the fineness decreases and floating fine floc appears after mixing water, and it is usually only partially miscible. Comparative Example 7 only uses sebacic acid, and the polarity gradient of the formula is weakened, the interfacial energy is increased, the emulsification is slow and coarser. Comparative Example 8 uses ethylene glycol instead of isosorbide, and the rigid-flexible matching and hydrophilic distribution are poor, and soft floc and micro-particles appear. Comparative Examples 9 and 10 are out of balance, respectively pushing towards network or insufficient interfacial membrane strength, resulting in thick emulsion white, fish eye or oil light, and obvious supernatant.

[0076] Table 2 Water-based performance test

[0077] Dilution results Appearance change Layering phenomenon Example 1 Completely miscible Uniform, milky white liquid None Example 2 Completely miscible Uniform, milky white liquid None Comparative Example 1 Partially miscible Coarse milky white, with visible fine particles Thin supernatant ring Comparative Example 2 Difficult to miscible Sticky, stringy, with local microgel Supernatant is obvious Comparative Example 3 Partially miscible Insufficient fineness, with floating fine floc Slight Comparative Example 7 Partially miscible Coarse milky white, with a long time required for uniformity Slight Comparative Example 8 Partially miscible Visible soft floc and micro particles Slight Comparative Example 9 Difficult to miscible Thick milky white, with fish eye or microgel Obvious Comparative Example 10 Partially miscible Loose milky white, with surface sheen Obvious

[0078] 3, Storage stability

[0079] The covalent grafting sites formed by the embodiments can maintain long-term inter-particle repulsion with a uniform amine salt layer, without stratification and sedimentation for 30 days, and the viscosity remains within a reasonable range. In Comparative Example 2, excessive amidation and bridging were caused by high temperature in one step, and obvious thickening to a semi-gel or gel-like sedimentation was observed within 30 days, which was extremely unstable. In Comparative Example 4, excessive grafting sites caused bridging, and the viscosity increased over time, resulting in microgel sedimentation, which was judged to be unstable. In Comparative Example 5, the temperature in the second stage was too high, and amidation continued to occur in the aqueous phase, reducing the surface charge sites, resulting in delayed flocculation and a small amount of sedimentation, which was unstable. In Comparative Example 6, only a small molecule amine salt layer was formed, which lacked structural anchoring, and slight stratification or turbidity was often observed within 30 days, with moderate deviation in stability. In Comparative Examples 1 and 3, the grafting sites were missing or insufficient, and weak flocculation was observed in the early stage, with slight stratification or fine sediment at the bottom within 30 days, which was poor in stability. In Comparative Examples 7 and 8, the polarity gradient and rigid-flexible matching were weakened, and the interfacial repulsion of the particles was insufficient, and supernatant and fine sediment were often observed within 30 days, which was unstable. In Comparative Examples 9 and 10, the proportion imbalance caused easy microgelization on one end and insufficient interfacial membrane strength on the other end, and significant thickening or obvious supernatant was observed within 30 days, respectively, which was unstable.

[0080] Table 3 30-day storage stability at 25°C

[0081]

[0082]

[0083] Obviously, the above embodiments of the present application are merely examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those of ordinary skill in the art. It is not necessary or possible to exhaust all embodiments. Any modifications, equivalent replacements, and improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A waterborne alkyd resin, characterized in that, It includes 20-24 parts erythritol, 6-8 parts isosorbide, 10-15 parts neodecanoic acid, 15-20 parts succinic acid, 15-20 parts sebacic acid, 2-3 parts citric acid, 5-7 parts isophorone diamine, 9-10 parts propylene glycol linoleate, and a catalyst.

2. The waterborne alkyd resin according to claim 1, characterized in that, The mass ratio of erythritol to isosorbide is 2.5–4:

1.

3. The waterborne alkyd resin according to claim 1, characterized in that, The mass ratio of succinic acid to sebacic acid is 0.75 to 1.5:

1.

4. The waterborne alkyd resin according to claim 1, characterized in that, Propylene glycol linoleate accounts for 9% to 11% of the total solid content of the alkyd resin.

5. The waterborne alkyd resin according to claim 1, characterized in that, Citric acid accounts for 6% to 9% of the total mass of neodecanoic acid, succinic acid, sebacic acid, and citric acid.

6. A method for preparing the aqueous alkyd resin according to any one of claims 1 to 5, characterized in that, Includes the following steps: First, erythritol and isosorbide are melted, then succinic acid and sebacic acid are added, followed by neodecanoic acid and a catalyst. The mixture is heated, and finally citric acid is added and the mixture is heated continuously. The temperature was lowered, and propylene glycol linoleate was added to continue the reaction; the temperature was further lowered, and isophorone diamine was added in two stages; after dispersion, the aqueous alkyd resin was obtained.

7. The method for preparing the waterborne alkyd resin according to claim 6, characterized in that, When the temperature is heated to 150-170℃ and the acid value drops to 60-80 mgKOH / g, citric acid is added; the temperature is then continuously heated to 190-200℃ to carry out the esterification reaction until the acid value drops below 30 mgKOH / g.

8. The method for preparing the waterborne alkyd resin according to claim 6, characterized in that, Cool to 140–155°C, add propylene glycol linoleate, and continue the reaction for 20–40 minutes.

9. The method for preparing the waterborne alkyd resin according to claim 6, characterized in that, When the temperature is lowered to 110-130℃, add 8%-12% of the total amount of isophorone diamine until the acid value decreases by 3-8 mg KOH / g; add the remaining isophorone diamine under conditions not exceeding 90℃ and in the presence of an aqueous phase, and disperse for 20-40 minutes.

10. An application of the waterborne alkyd resin according to any one of claims 1 to 5, characterized in that, Used in the preparation of adhesives or coatings.

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