Hyperbranched polyhydroxy polyester resin, preparation method thereof and application of hyperbranched polyhydroxy polyester resin in preparation of acrylic resin coating

Abstract

The invention provides hyperbranched polyhydroxy polyester resin as well as a preparation method and application thereof in preparation of an acrylic resin coating, and relates to the technical field of polymer coating compositions. According to the hyperbranched polyhydroxy polyester resin, pentaerythritol is adopted as a core, succinic anhydride, tetramethyl cyclobutanediol and trimellitic anhydride are sequentially connected to a hyperbranched molecular structure in a comonomer form through a continuous esterification reaction method, and the hyperbranched polyhydroxy polyester resin is prepared. In the preparation process of the hyperbranched polyhydroxy polyester resin, the reaction process can be controlled only through an acid value, meanwhile, polyester with a hyperbranched structure is synthesized by adopting a one-pot method, and the hyperbranched polyhydroxy polyester resin has the technical advantages that the synthetic resin step is simple, and a separation process is not needed. The hyperbranched polyhydroxy polyester resin can be widely applied to the preparation process of an acrylic resin coating.

Description

Technical Field

[0001] The invention relates to the technical field of polymer coating compositions, in particular to a hyperbranched polyhydroxy polyester resin and a preparation method thereof and application thereof in the preparation of acrylic resin coatings. Background Art

[0002] Compared with conventional resins, high-solid resins have lower solvent content, lower odor, and better environmental protection and safety performance. But the problem that comes with it is that this type of resin generally has a high viscosity and is not easy to construct. Hyperbranched resins have special structures. They are usually lower in viscosity and better in fluidity than straight-chain resins, making them easier to construct. However, the process of synthesizing resins with hyperbranched structures is complicated, with many by-products, uncontrollable polymerization processes, and easy gelation. At the same time, ordinary polyhydroxy polyester resins will encounter the problem of slow drying when used in the field of quick-drying coatings in combination with isocyanates. The reason is that the resin Tg (glass transition temperature) is low. Although using more aromatic polyacids will increase the Tg value of the resin, the side effect is that due to the structural differences, the compatibility of the synthesized resin with acrylic resin becomes poor.

[0003] Therefore, it is necessary and urgent to study and develop a method for preparing a hyperbranched polyhydroxy polyester resin to alleviate the problem of complicated existing hyperbranched resin preparation process and the problem of poor compatibility between the hyperbranched polyhydroxy polyester resin and acrylic resin.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The object of the present invention is to provide a hyperbranched polyhydroxy polyester resin and a preparation method thereof. In the preparation process of the hyperbranched polyhydroxy polyester resin, the reaction process can be controlled only by the acid value, and the polyester with a hyperbranched structure is synthesized by a "one-pot method", which has the technical advantages of simple steps for synthesizing the resin and no need for a separation process. The hyperbranched polyhydroxy polyester resin can be widely used in the preparation process of acrylic resin coatings.

[0006] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0007] The invention provides a hyperbranched polyhydroxy polyester resin, wherein the hyperbranched polyhydroxy polyester resin is prepared by continuous esterification reaction with pentaerythritol as a core, succinic anhydride, tetramethylcyclobutanediol and trimellitic anhydride as comonomers;

[0008] The continuous esterification reaction comprises: adding succinic anhydride, tetramethylcyclobutanediol and trimellitic anhydride to a pentaerythritol solution in sequence for esterification condensation to obtain a hyperbranched polyhydroxy polyester resin;

[0009] The continuous esterification reaction is controlled by acid value.

[0010] The molecular weight of the hyperbranched polyhydroxy polyester is 1000 to 3000;

[0011] Preferably, the hydroxyl value of the hyperbranched polyhydroxy polyester is 150 to 200 mgKOH / g;

[0012] Preferably, the branching degree of the hyperbranched polyhydroxy polyester is 0.5 to 0.8;

[0013] Preferably, the hyperbranched polyhydroxy polyester has a viscosity of 400-700 cps / 25°C.

[0014] Furthermore, the solvent of the pentaerythritol solution is a low boiling point solvent;

[0015] Preferably, the solvent includes at least one of aromatic hydrocarbons, ketones and ester solvents, preferably xylene.

[0016] Furthermore, the continuous esterification reaction is carried out under constant temperature and pressure conditions;

[0017] Preferably, the temperature of the continuous esterification reaction is 100°C;

[0018] Preferably, the pressure of the continuous esterification reaction is -0.1 to 0.2 MPa.

[0019] The present invention provides a method for preparing the hyperbranched polyhydroxy polyester resin, the method comprising:

[0020] A calculated molar ratio of succinic anhydride is added to a pentaerythritol solution to react until the acid value is constant, then a calculated molar ratio of tetramethylcyclobutanediol is added to react until the acid value is constant, and then a calculated molar ratio of trimellitic anhydride is added to react until the acid value is constant to obtain a solution containing a hyperbranched polyhydroxy polyester resin.

[0021] Furthermore, the calculated molar ratio of pentaerythritol to succinic anhydride is 1:2 to 4, preferably 1:4;

[0022] Preferably, the calculated molar ratio of tetramethylcyclobutanediol to succinic anhydride is 1:1 to 2, preferably 1:1;

[0023] Preferably, the calculated molar ratio of trimellitic anhydride to tetramethylcyclobutanediol is 1:1-2, preferably 1:1.

[0024] Furthermore, the preparation method further comprises: adding an epoxy compound to a solution containing the hyperbranched polyhydroxy polyester resin to adjust the Tg value of the hyperbranched polyhydroxy polyester resin;

[0025] Preferably, the Tg value of the hyperbranched polyhydroxy polyester resin after adjustment by the epoxy compound is -20 to 80°C;

[0026] Preferably, the epoxy compound includes at least one of butyl glycidyl ether, dodecyl glycidyl ether, neodecanoic acid glycidyl ester, and phenyl glycidyl ether, preferably butyl glycidyl ether.

[0027] Furthermore, the preparation method further comprises: a step of removing the solvent in the solution containing the hyperbranched polyhydroxy polyester resin;

[0028] Preferably, the solvent in the hyperbranched polyhydroxy polyester resin solution is removed by reduced pressure distillation.

[0029] The present invention provides an application of the hyperbranched polyhydroxy polyester resin in the preparation of acrylic resin coatings.

[0030] The present invention provides an acrylic resin coating composition, which comprises, by mass percentage:

[0031] Hyperbranched polyhydroxy polyester resin 5.4-14.7%, hydroxy acrylic resin 49.6-58.9%, T-12 catalyst 1-2%, leveling agent 1-2%, solvent 9-10.7%, isocyanate 22-23.7%;

[0032] The sum of the mass percentages of the components in the acrylic resin coating composition is 100%.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The hyperbranched polyhydroxy polyester resin provided by the present invention uses pentaerythritol as a core, and sequentially connects succinic anhydride, tetramethylcyclobutanediol, and trimellitic anhydride in the form of comonomers to a hyperbranched molecular structure through a continuous esterification reaction method to prepare the hyperbranched polyhydroxy polyester resin. The preparation process of the hyperbranched polyhydroxy polyester resin can control the reaction process only by acid value, and a polyester with a hyperbranched structure is synthesized by a "one-pot method", which has the technical advantages of simple steps for synthesizing the resin and no need for a separation process.

[0035] The preparation method of the hyperbranched polyhydroxy polyester resin of the present invention sequentially adds succinic anhydride, tetramethylcyclobutanediol and trimellitic anhydride into a pentaerythritol solution by controlling the acidity to prepare the hyperbranched polyhydroxy polyester resin, and has the advantages of simple processing technology and easy operation.

[0036] The hyperbranched polyhydroxy polyester resin provided by the present invention can be widely used in the preparation process of acrylic resin coatings.

[0037] The acrylic resin coating composition provided by the present invention is composed of the hyperbranched polyhydroxy polyester resin, hydroxy acrylic resin, T-12 catalyst, leveling agent, solvent and isocyanate in a specific ratio. The hyperbranched polyhydroxy polyester resin in the acrylic resin coating composition is compatible with the hydroxy acrylic resin and is not turbid, and can effectively reduce the apparent viscosity of the acrylic resin coating, and has good impact resistance and gasoline resistance. The prepared cured film has the advantages of good weather resistance and strong gloss. DETAILED DESCRIPTION

[0038] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] According to one aspect of the present invention, a hyperbranched polyhydroxy polyester resin is prepared by continuous esterification reaction using pentaerythritol as a core and succinic anhydride, tetramethylcyclobutanediol and trimellitic anhydride as comonomers;

[0040] The continuous esterification reaction comprises: adding succinic anhydride, tetramethylcyclobutanediol and trimellitic anhydride to a pentaerythritol solution in sequence for esterification condensation to obtain a hyperbranched polyhydroxy polyester resin;

[0041] The continuous esterification reaction is controlled by acid value.

[0042] The hyperbranched polyhydroxy polyester resin provided by the present invention uses pentaerythritol as a core, and sequentially connects succinic anhydride, tetramethylcyclobutanediol, and trimellitic anhydride in the form of comonomers to a hyperbranched molecular structure through a continuous esterification reaction method to prepare the hyperbranched polyhydroxy polyester resin. The preparation process of the hyperbranched polyhydroxy polyester resin can control the reaction process only by acid value, and a polyester with a hyperbranched structure is synthesized by a "one-pot method", which has the technical advantages of simple steps for synthesizing the resin and no need for a separation process.

[0043] It should be noted that the technical principle of the hyperbranched polyhydroxy polyester resin of the present invention is as follows:

[0044] The tetramethylcyclobutanediol of the present invention has a rigid aliphatic ring in the molecule. The polyester resin with a hyperbranched structure is synthesized by combining the diol with an aliphatic polyol (such as pentaerythritol) and a polyacid anhydride (such as succinic anhydride, phthalic anhydride, etc.), which not only overcomes the disadvantage of the incompatibility between the traditional polyester resin and the acrylic resin, but also effectively avoids the reduction of the Tg of the resin.

[0045] In a preferred embodiment of the present invention, the molecular weight of the hyperbranched polyhydroxy polyester is 1000 to 3000;

[0046] Preferably, the hydroxyl value of the hyperbranched polyhydroxy polyester is 150 to 200 mgKOH / g;

[0047] Preferably, the branching degree of the hyperbranched polyhydroxy polyester is 0.5 to 0.8;

[0048] Preferably, the hyperbranched polyhydroxy polyester has a viscosity of 400-700 cps / 25°C.

[0049] In a preferred embodiment of the present invention, the solvent of the pentaerythritol solution is a low boiling point solvent;

[0050] Preferably, the solvent includes at least one of aromatic hydrocarbons, ketones and ester solvents, preferably xylene.

[0051] As a preferred embodiment, the pentaerythritol solution of the present invention is prepared using a low boiling point solvent, and after the synthesis is completed, the hyperbranched polyhydroxy polyester can be obtained by removing the solvent through simple distillation.

[0052] In a preferred embodiment of the present invention, the continuous esterification reaction is carried out under constant temperature and pressure conditions;

[0053] Preferably, the temperature of the continuous esterification reaction is 100°C;

[0054] Preferably, the pressure of the continuous esterification reaction is -0.1 to 0.2 MPa.

[0055] According to one aspect of the present invention, a method for preparing the above-mentioned hyperbranched polyhydroxy polyester resin comprises:

[0056] A calculated molar ratio of succinic anhydride is added to a pentaerythritol solution to react until the acid value is constant, then a calculated molar ratio of tetramethylcyclobutanediol is added to react until the acid value is constant, and then a calculated molar ratio of trimellitic anhydride is added to react until the acid value is constant to obtain a solution containing a hyperbranched polyhydroxy polyester resin.

[0057] The preparation method of the hyperbranched polyhydroxy polyester resin of the present invention is to add succinic anhydride, tetramethylcyclobutanediol and trimellitic anhydride to a pentaerythritol solution in sequence by controlling the acidity to prepare the hyperbranched polyhydroxy polyester resin. The preparation method can synthesize the polyester with a hyperbranched structure by only a "one-pot method", and the preparation process does not require a separation step, and has the advantages of simple processing technology and easy operation.

[0058] In a preferred embodiment of the present invention, the calculated molar ratio of pentaerythritol to succinic anhydride is 1:2 to 4, preferably 1:4;

[0059] Preferably, the calculated molar ratio of tetramethylcyclobutanediol to succinic anhydride is 1:1 to 2, preferably 1:1;

[0060] Preferably, the calculated molar ratio of trimellitic anhydride to tetramethylcyclobutanediol is 1:1-2, preferably 1:1.

[0061] In a preferred embodiment of the present invention, the preparation method further comprises: adding an epoxy compound to a solution containing the hyperbranched polyhydroxy polyester resin to adjust the Tg value of the hyperbranched polyhydroxy polyester resin;

[0062] As a preferred embodiment, the present invention changes the Tg value of the resin by changing the chain length of the fatty chain of the epoxy compound.

[0063] Preferably, the Tg value of the hyperbranched polyhydroxy polyester resin after adjustment by the epoxy compound is -20 to 80°C;

[0064] Preferably, the epoxy compound includes at least one of butyl glycidyl ether, dodecyl glycidyl ether, neodecanoic acid glycidyl ester, and phenyl glycidyl ether, preferably butyl glycidyl ether.

[0065] In a preferred embodiment of the present invention, the preparation method further comprises: a step of removing the solvent in the solution containing the hyperbranched polyhydroxy polyester resin;

[0066] Preferably, the solvent in the hyperbranched polyhydroxy polyester resin solution is removed by reduced pressure distillation.

[0067] According to one aspect of the present invention, a use of the hyperbranched polyhydroxy polyester resin in the preparation of acrylic resin coating.

[0068] The hyperbranched polyhydroxy polyester resin provided by the present invention can be widely used in the preparation process of acrylic resin coatings.

[0069] According to one aspect of the present invention, an acrylic resin coating composition, measured by mass percentage, comprises:

[0070] Hyperbranched polyhydroxy polyester resin 5.4-14.7%, hydroxy acrylic resin 49.6-58.9%, T-12 catalyst 1-2%, leveling agent 1-2%, solvent 9-10.7%, isocyanate 22-23.7%;

[0071] The sum of the mass percentages of the components in the acrylic resin coating composition is 100%.

[0072] The acrylic resin coating composition provided by the present invention is composed of the hyperbranched polyhydroxy polyester resin, hydroxy acrylic resin, T-12 catalyst, leveling agent, solvent and isocyanate in a specific ratio. The hyperbranched polyhydroxy polyester resin in the acrylic resin coating composition is compatible with the hydroxy acrylic resin and is not turbid, and can effectively reduce the apparent viscosity of the acrylic resin coating, and has good impact resistance and gasoline resistance. The prepared cured film has the advantages of good weather resistance and strong gloss.

[0073] The technical solution of the present invention will be further described below in conjunction with embodiments.

[0074] Example 1

[0075] A method for preparing a hyperbranched polyhydroxy polyester resin, the preparation method comprising:

[0076] (A) 100.0 g of solvent (xylene) and 20.42 (0.15 mol) of pentaerythritol were added to a four-necked flask equipped with a mechanical stirrer, a condenser, a thermometer, and a constant pressure funnel, and then the flask was heated to 100° C. under reflux to obtain a pentaerythritol solution to be reacted.

[0077] (B), adding 60 g (0.6 mol) of succinic anhydride to the pentaerythritol solution through a constant pressure funnel to react until the acid value is constant, to obtain an intermediate solution A; the molar ratio of pentaerythritol to succinic anhydride is 1:4;

[0078] Subsequently, 80.52 g (0.6 mol) of tetramethylcyclobutanediol was added to the intermediate solution A to react until the acid value was constant, thereby obtaining an intermediate solution B; the molar ratio of the tetramethylcyclobutanediol to succinic anhydride was 1:1;

[0079] Then, 115.27 g (0.6 mol) of trimellitic anhydride was added to the intermediate solution B to react until the acid value was constant, thereby obtaining a solution containing a hyperbranched polyhydroxy polyester resin; the molar ratio of the trimellitic anhydride to tetramethylcyclobutanediol was 1:1.

[0080] (C) slowly adding 128.98 g (1.2 mol) of butyl glycidyl ether into the solution containing the hyperbranched polyhydroxy polyester resin to adjust the Tg value of the hyperbranched polyhydroxy polyester resin, wherein the Tg value of the hyperbranched polyhydroxy polyester resin after adjustment is 57° C.;

[0081] (D) removing the solvent xylene by reduced pressure distillation to obtain a hyperbranched polyhydroxy polyester resin.

[0082] The process of the reduced pressure distillation method includes: using an oil bath as a heat-conducting medium, the vacuum degree of the vacuum pump is -0.09 to 0.1, heating the material in the container to 90 to 100° C., and maintaining this state for 2 to 3 hours.

[0083] Example 2

[0084] A method for preparing a hyperbranched polyhydroxy polyester resin, the preparation method comprising:

[0085] (A) Add 50.0 g of solvent (xylene) and 13.6 (0.1 mol) of pentaerythritol into a four-necked flask equipped with a mechanical stirrer, a condenser, a thermometer, and a constant pressure funnel, and then heat the flask to 100° C. under reflux to obtain a pentaerythritol solution to be reacted.

[0086] (B), adding 40 g (0.4 mol) of succinic anhydride to the pentaerythritol solution through a constant pressure funnel to react until the acid value is constant, to obtain an intermediate solution A; the molar ratio of pentaerythritol to succinic anhydride is 1:4;

[0087] Subsequently, 57.68 g (0.4 mol) of tetramethylcyclobutanediol was added to the intermediate solution A to react until the acid value was constant, thereby obtaining an intermediate solution B; the molar ratio of the tetramethylcyclobutanediol to succinic anhydride was 1:1;

[0088] Then, 76.85 g (0.4 mol) of trimellitic anhydride was added to the intermediate solution B to react until the acid value was constant, thereby obtaining a solution containing a hyperbranched polyhydroxy polyester resin; the molar ratio of the trimellitic anhydride to tetramethylcyclobutanediol was 1:1.

[0089] (C), slowly adding 104.14 g (0.8 mol) of butyl glycidyl ether into the solution containing the hyperbranched polyhydroxy polyester resin to adjust the Tg value of the hyperbranched polyhydroxy polyester resin, wherein the Tg value of the hyperbranched polyhydroxy polyester resin after adjustment is 58° C.;

[0090] (D) removing the solvent xylene by reduced pressure distillation to obtain a hyperbranched polyhydroxy polyester resin.

[0091] The process of the vacuum distillation method is the same as that of Example 1.

[0092] Example 3

[0093] A method for preparing a hyperbranched polyhydroxy polyester resin, the preparation method comprising:

[0094] (A), same as in Example 2;

[0095] (B), same as in Example 2;

[0096] (C) slowly adding a mixture of 50.07 g (0.4 mol) of butyl glycidyl ether and 60.07 g (0.4 mol) of benzyl glycidyl ether into a solution containing a hyperbranched polyhydroxy polyester resin to adjust the Tg value of the hyperbranched polyhydroxy polyester resin, wherein the Tg value of the hyperbranched polyhydroxy polyester resin after adjustment is 64° C.;

[0097] (D) removing the solvent xylene by reduced pressure distillation to obtain a hyperbranched polyhydroxy polyester resin.

[0098] The process of the vacuum distillation method is the same as that of Example 1.

[0099] The changes in the acid values ​​of the systems of Examples 1 to 3 are shown in the following table:

[0100]

[0101] In the embodiments 1 to 3, succinic anhydride is added to the pentaerythritol solution to react until the acid value of the acid ester is constant in the range of 171.42 to 202.7; tetramethylcyclobutanediol is added to react until the acid value is constant in the range of 4.7 to 5.1; and trimellitic anhydride is added to react until the acid value is constant in the range of 122 to 188.1.

[0102] Test Example 1

[0103] The commercially available F1190, TEC3666 and Examples 1 to 3 were all tested for resin fluidity using a rotational viscometer, and the time results were recorded as shown in the following table:

[0104] Flying F1190 1500 / cps TEC3666 1000 / cps Example 1 700 / cps Example 2 700 / cps Example 3 700 / cps

[0105] Test Example 2

[0106] The surface drying time of the paint films of Examples 1, 2 and 3 above when cured by isocyanate was tested, and the specific results are shown in the following table:

[0107] Example 1 120min Example 2 112min Example 3 93min

[0108] Embodiments 4 to 6

[0109] An acrylic resin coating composition, which comprises, by mass percentage:

[0110]

[0111]

[0112] The source of the hydroxy acrylic resin in the above Examples 4 to 6 is not particularly limited and can be synthesized by itself or purchased as a finished product. The molecular weight thereof is 4000±1000, the acid value is 1 to 10 mg KOH / g, and the hydroxyl content is 2 to 6%.

[0113] Exemplary, the synthesis method of hydroxy acrylic resin is as follows:

[0114] Add a portion of the reaction solvent to a 500ml four-necked reaction flask equipped with a mechanical stirrer. After the solvent refluxes, add the monomer mixed solution containing the initiator prepared according to the formula shown in the table to the reaction flask at a constant speed using a constant pressure dropping funnel. After the monomer addition is completed; add an initiator with a monomer content of 0.2% under reflux and keep warm for 2.5 hours. After the insulation is completed, vacuum extract a certain amount of reaction solvent and add an appropriate amount of solvent to dilute the resin.

[0115] The hydroxy acrylic resin formula is shown in the following table:

[0116] Styrene 20-25％ Butyl acrylate 17-42％ Butyl Methacrylate 10-15％ Hydroxyl-containing monomer (HEMA) 18-30％ AA 0.5-1.5％ Initiator 0.5-10％

[0117] The preparation method of the acrylic resin coating composition comprises:

[0118] According to the mass percentage, the hyperbranched polyhydroxy polyester resin, hydroxy acrylic resin, T-12 catalyst, leveling agent and isocyanate are added to a three-necked flask equipped with a mechanical stirrer and a reflux condenser, and then an appropriate amount of solvent is added to the flask to adjust to the required viscosity and solid content to obtain an acrylic resin coating.

[0119] Example 7

[0120] This embodiment is the same as Embodiment 5 except that the “hyperbranched polyhydroxy polyester resin of Embodiment 1” in the acrylic resin coating composition is replaced by the “hyperbranched polyhydroxy polyester resin of Embodiment 2”.

[0121] Example 8

[0122] This embodiment is the same as Embodiment 5 except that the “hyperbranched polyhydroxy polyester resin of Embodiment 1” in the acrylic resin coating composition is replaced by “hyperbranched polyhydroxy polyester resin of Embodiment 3”.

[0123] Test Example 3

[0124] In order to show that the hyperbranched polyhydroxy polyester resin in the acrylic resin coating prepared by the present invention can be compatible with the hydroxy acrylic resin without turbidity, and can effectively reduce the apparent viscosity of the acrylic resin coating, and has good impact resistance and gasoline resistance, and the prepared cured film has the advantages of good weather resistance and strong gloss. The performance of the acrylic resin coating prepared in Examples 4 to 6 is now tested, and the specific method is as follows:

[0125] Format viscosity test: The format tube viscometer is a glass tube with an inner diameter of about 10.75mm and a height of 115mm, with two scale lines at 100 and 108mm. During the test, pour the sample into the viscosity tube, about to the 100mm scale line, plug it with a stopper, and put it in 25℃ water. After 10 minutes, adjust the liquid level to exactly 100mm, plug it to the 108mm scale line, and continue to put it in a 25℃ constant temperature water bath. After 10 minutes, quickly invert the viscosity tube, and place the viscosity tube vertically in a 25℃ water bath to measure the time required for the bubble to rise to the top of the viscosity tube.

[0126] Gloss test: According to ASTM D523 1999 specular gloss test method, the test was performed using a 60-degree gloss meter.

[0127] Impact resistance test: The impact resistance of the resin is tested according to GB1732-79 (88), and is expressed as the product of the tearing mass and the starting height (kg*cm). The larger the value, the better the impact resistance.

[0128] Hardness test: The hardness of the sample is tested according to GB / T1730-93. The larger the value, the higher the hardness.

[0129] Solvent resistance test: The resin's resistance to acid, alkali and organic solvents is tested in accordance with the method specified in GB / T1748-1999.

[0130] The specific test results are shown in the following table:

[0131]

[0132]

[0133] Note: The control group in the above table is an acrylic resin cured film without the hyperbranched polyhydroxy polyester resin of the present invention, and its raw material composition is shown in the following table:

[0134] Components Dosage Hyperbranched polyester 0 Acrylic resin 64.3 T-12 Catalyst 1.5 Leveling agent 1.5 Solvent 8 Isocyanate 24.7

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hyperbranched polyhydroxy polyester resin, characterized in that The hyperbranched polyhydroxy polyester resin is prepared by continuous esterification reaction with pentaerythritol as the core and succinic anhydride, tetramethylcyclobutanediol and trimellitic anhydride as comonomers; The continuous esterification reaction comprises: adding succinic anhydride, tetramethylcyclobutanediol and trimellitic anhydride to a pentaerythritol solution in sequence for esterification condensation to obtain a hyperbranched polyhydroxy polyester resin; The continuous esterification reaction is controlled by acid value.

2. The hyperbranched polyhydroxy polyester resin according to claim 1, characterized in that The molecular weight of the hyperbranched polyhydroxy polyester is 1000 to 3000; Preferably, the hydroxyl value of the hyperbranched polyhydroxy polyester is 150 to 200 mgKOH / g; Preferably, the branching degree of the hyperbranched polyhydroxy polyester is 0.5 to 0.8; Preferably, the hyperbranched polyhydroxy polyester has a viscosity of 400-700 cps / 25°C.

3. The hyperbranched polyhydroxy polyester resin according to claim 1, characterized in that The solvent of the pentaerythritol solution is a low boiling point solvent; Preferably, the solvent includes at least one of aromatic hydrocarbons, ketones and ester solvents, preferably xylene.

4. The hyperbranched polyhydroxy polyester resin according to claim 1, characterized in that The continuous esterification reaction is carried out under constant temperature and pressure conditions; Preferably, the temperature of the continuous esterification reaction is 100°C; Preferably, the pressure of the continuous esterification reaction is -0.1 to 0.2 MPa.

5. A method for preparing a hyperbranched polyhydroxy polyester resin according to any one of claims 1 to 4, characterized in that: The preparation method comprises: A calculated molar ratio of succinic anhydride is added to a pentaerythritol solution to react until the acid value is constant, then a calculated molar ratio of tetramethylcyclobutanediol is added to react until the acid value is constant, and then a calculated molar ratio of trimellitic anhydride is added to react until the acid value is constant to obtain a solution containing a hyperbranched polyhydroxy polyester resin.

6. The method for preparing a hyperbranched polyhydroxy polyester resin according to claim 5, characterized in that: The calculated molar ratio of pentaerythritol to succinic anhydride is 1:2 to 4, preferably 1:4; Preferably, the calculated molar ratio of tetramethylcyclobutanediol to succinic anhydride is 1:1 to 2, preferably 1:1; Preferably, the calculated molar ratio of trimellitic anhydride to tetramethylcyclobutanediol is 1:1-2, preferably 1:

1.

7. The method for preparing a hyperbranched polyhydroxy polyester resin according to claim 5, characterized in that: The preparation method further comprises: The step of adding an epoxy compound to a solution containing a hyperbranched polyhydroxy polyester resin to adjust the Tg value of the hyperbranched polyhydroxy polyester resin; Preferably, the Tg value of the hyperbranched polyhydroxy polyester resin after adjustment by the epoxy compound is -20 to 80°C; Preferably, the epoxy compound includes at least one of butyl glycidyl ether, dodecyl glycidyl ether, neodecanoic acid glycidyl ester, and phenyl glycidyl ether, preferably butyl glycidyl ether.

8. The method for preparing a hyperbranched polyhydroxy polyester resin according to claim 5, characterized in that: The preparation method further comprises: A step of removing the solvent from the solution containing the hyperbranched polyhydroxy polyester resin; Preferably, the solvent in the hyperbranched polyhydroxy polyester resin solution is removed by reduced pressure distillation.

9. Use of the hyperbranched polyhydroxy polyester resin according to any one of claims 1 to 4 in the preparation of acrylic resin coatings.

10. An acrylic resin coating composition, characterized in that: Measured by mass percentage, the acrylic resin coating composition comprises: 5.4-14.7% of the hyperbranched polyhydroxy polyester resin according to any one of claims 1 to 4, 49.6-58.9% of hydroxy acrylic resin, 1-2% of T-12 catalyst, 1-2% of leveling agent, 9-10.7% of solvent, and 22-23.7% of isocyanate; The sum of the mass percentages of the components in the acrylic resin coating composition is 100%.

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