Hyperbranched prepolymer, ultraviolet curing coating and preparation methods of hyperbranched prepolymer and coating

Abstract

The invention discloses a hyperbranched prepolymer which is prepared from the following components in percentage by mass: 20-26% of a monomer, 0.02-0.25% of an initiator, 0.1-0.6% of a chain transfer agent and 73.4-79.5% of a solvent, and also discloses an ultraviolet curing coating which comprises the hyperbranched prepolymer and is prepared from the following components in percentage by mass: 70-87% of the hyperbranched prepolymer, 12-28% of a reactive diluent and 0.8-2% of a photoinitiator. In the preparation process, excessive reactive diluents do not need to be added, the cost is greatly reduced, pollution is reduced, excellent photocuring performance is shown, the crosslinking phenomenon is effectively avoided, the molecular weight is increased, the viscosity is reduced, the reaction conditions are mild, operation and control are easy, and the method is suitable for large-scale industrial production. The hyperbranched prepolymer has excellent curing performance and physical performance, can be widely applied to the industries of coatings, adhesives, plastics and the like, and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of fine chemical coating materials and applications, and specifically relates to a hyperbranched prepolymer, an ultraviolet light-cured coating, and a preparation method of the hyperbranched prepolymer and the coating. Background Art

[0002] Acrylic resin is an important synthetic resin widely used in coatings, adhesives, plastics and other industries. Traditional acrylic resin is a linear polymer obtained by free radical polymerization with methacrylate monomer as the main raw material. However, this polymer is prone to intermolecular entanglement at high concentrations, forming a large resistance to movement, which is manifested as high viscosity. It is easy to cross-link during the synthesis process, and a large amount of diluent needs to be added during the use process to reduce the viscosity, which not only wastes resources but also pollutes the environment. Polyurethane resin is a type of resin that uses isocyanate as the main raw material and undergoes polymerization under the action of alcohol and phenolic compounds. It has excellent physical properties and good corrosion resistance and is widely used in coatings, adhesives, polyurethane elastomers and other fields. Traditional polyurethane elastomers have problems such as high organic solvent content and high environmental pollution during the preparation process. Hyperbranched polymers have a highly branched molecular structure, are not easy to entangle between molecules, have low viscosity, contain a large number of external active end groups and internal cavity structures, and have broad application value. For example, as a base resin for coatings, it is widely used in UV-curing coatings, powder coatings, and alkyd resin coatings.

[0003] The existing technical scheme mainly adopts the method of free radical chain polymerization to prepare acrylic resin. The acrylic resin prepared by this method has high viscosity, low molecular weight and is not easy to use. Traditional polyurethane elastomers are prepared by condensation polymerization of step-by-step polymerization. The polyurethane elastomers prepared by this method have problems such as high organic solvent content and large environmental pollution during the preparation process. The problems or shortcomings of the prior art in this field are mainly reflected in the following aspects: First, the acrylic resin prepared by the traditional method has high viscosity, low molecular weight, is not easy to use, and there is a phenomenon of gelation during the preparation process. Secondly, the traditional polyurethane elastomer has problems such as high organic solvent content and large environmental pollution during the preparation process. Therefore, it is very necessary to introduce a hyperbranched structure when preparing a prepolymer. While reducing the viscosity of the system, it is also possible to reduce the amount of organic solvent used during use and reduce the degree of pollution to the environment. However, the polymerization reaction of preparing acrylic resin from vinyl monomers (acrylic acid, acrylate, etc.) is a free radical chain polymerization, so it is difficult to obtain a hyperbranched structure. Summary of the invention

[0004] The present invention mainly solves the following problems: a. the problems that the acrylic resin prepared by the traditional method has high viscosity, low molecular weight, is difficult to use, and gelling occurs during the preparation process; b. the problems that the traditional polyurethane elastomer has a large organic solvent content and causes great environmental pollution during the preparation process; and c. the problem that the polymerization reaction of preparing the acrylic resin from vinyl monomers (acrylic acid, acrylate, etc.) is free radical chain polymerization, so it is difficult to obtain a hyperbranched structure.

[0005] The present invention provides a hyperbranched prepolymer, which is composed of the following components by mass percentage:

[0006]

[0007] The monomer is composed of a multifunctional monomer, a hydroxyl-containing monomer, and an isocyanate monomer having an isocyanate group at one end and a double bond group at the other end of the linear monomer, wherein the mass ratio of the multifunctional monomer: the hydroxyl-containing monomer: the isocyanate monomer having an isocyanate group at one end and a double bond group at the other end of the linear monomer is 15-20:1:1-1.5;

[0008] The multifunctional monomer is one or more of tridecafluorooctyl acrylate, 1,6-hexanediol diacrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, di(trimethylolpropane) tetraacrylate, and polydipentaerythritol hexaacrylate.

[0009] The monomer containing a hydroxyl group is hydroxyethyl methacrylate.

[0010] The linear isocyanate monomer having an isocyanate group at one end and a double bond group at the other end is methacrylate isocyanate.

[0011] The initiator is one or more of benzoyl peroxide (BPO), azobisisobutyronitrile (AIBN), and dimethyl azobisisobutyrate (AIBME);

[0012] The chain transfer agent is one of GTP and DK-08;

[0013] The solvent is one of butyl acetate and trifluorotoluene

[0014] The second object of the present invention is to provide a method for preparing the above-mentioned hyperbranched prepolymer:

[0015] Weigh the solvent according to the formula amount and add it into a three-necked flask, start stirring, control the stirring rate to (300-400) r / min, and start to slowly heat up. When the system temperature reaches (115-120) ° C, start to slowly drop the mixed solution of multifunctional monomer, hydroxyl-containing monomer and chain transfer agent. After the dropwise addition is completed, stir at this temperature for 30 minutes, add the initiator and stir continuously, keep the temperature for reaction for 3 hours, after the insulation is completed, cool to (50-60) ° C, and then drop a linear isocyanate monomer containing an isocyanate group at one end and a double bond group at the other end. After the dropwise addition is completed, keep the temperature for reaction for 2 hours, then heat to 80 ° C for distillation. When the distillate no longer drips out, stop the distillation, cool down and discharge, and obtain a colorless hyperbranched prepolymer.

[0016] The third object of the present invention is to provide the above-mentioned UV-curable coating, which comprises the above-mentioned hyperbranched prepolymer and is composed of the following components calculated by mass percentage:

[0017] Hyperbranched prepolymer 70~87%

[0018] Active diluent 12~28%

[0019] Photoinitiator 0.8~2%

[0020] The active diluent is G06C;

[0021] The photoinitiator is 2-hydroxy-2-methyl-1-phenylpropanone (1173).

[0022] The fourth object of the present invention is to provide a method for preparing the above-mentioned UV-curable coating: hyperbranched prepolymer, reactive diluent and photoinitiator are weighed according to the formula amount, stirred evenly in a disposable cup, and the UV-curable coating is obtained.

[0023] The mixture was allowed to stand for 10 minutes, poured onto a glass plate and leveled to a thickness of about 1 mm to 2 mm, and then irradiated with a handheld UV lamp, controlling the intensity of the UV light to 500 μW / cm 2 The front side was irradiated for 30 seconds and the back side was irradiated for 30 seconds to obtain a UV-curing coating color plate.

[0024] This technical solution mainly adopts the following technical means: a. Preparation of hyperbranched polymers with terminal hydroxyl groups: Polymerization reaction is carried out using multifunctional monomers and monomers containing hydroxyl groups to prepare the first step reactant with a highly branched molecular structure, which is not easy to entangle between molecules, has low viscosity, and contains a large number of external active end groups. b. Preparation of hyperbranched polyurethane acrylate prepolymer by terminal modification method: Using the terminal modification method, the prepared first step reactant is reacted with a linear isocyanate monomer containing an isocyanate group at one end and a double bond group at the other end to obtain a hyperbranched polyurethane acrylate prepolymer. This reaction method can effectively introduce a hyperbranched structure and improve the reactivity of the prepolymer, while avoiding the problem that it is difficult to obtain a hyperbranched structure by traditional free radical chain polymerization. c. Application of hyperbranched polyurethane acrylate prepolymer in UV-curing coatings: The prepared hyperbranched polyurethane acrylate prepolymer is applied to UV-curing coatings. Since the hyperbranched polyurethane acrylate prepolymer has a high degree of branching and a large number of functional groups that can participate in the curing reaction, the curing speed and film performance of the UV-curing coating can be greatly improved. At the same time, due to the introduction of the hyperbranched structure, the viscosity of the system is reduced, the amount of organic solvent used is reduced, and the degree of environmental pollution is reduced.

[0025] Beneficial Effects

[0026] Compared with the existing technology, the beneficial effects of this technical solution are as follows:

[0027] a. Introducing hyperbranched structures: In the preparation process, the present invention can well adjust the viscosity of the system by introducing hyperbranched structures, and does not need to add too much reactive diluent during use, greatly reducing costs and pollution and showing excellent photocuring performance. This is impossible to achieve in the prior art.

[0028] b. Solve the cross-linking phenomenon: Traditional macromolecular chain prepolymers are prone to cross-linking during the synthesis process, and have defects such as small molecular weight and high viscosity, which are difficult to produce and use, limiting their wide application in related fields. The hyperbranched prepolymer of the present invention can effectively avoid the cross-linking phenomenon, increase the molecular weight and reduce the viscosity, thereby improving the performance of the prepolymer.

[0029] c. Reduce the amount of organic solvents: Traditional polyurethane elastomers have problems such as high organic solvent content and high environmental pollution during the preparation process. The hyperbranched prepolymer of the present invention can reduce the viscosity of the system while reducing the amount of organic solvents and the degree of environmental pollution by introducing a hyperbranched structure, which has obvious advantages over the prior art.

[0030] d. Simplified preparation process: The preparation method of the present invention is simple, the reaction conditions are mild, it is easy to operate and control, and it is suitable for large-scale industrial production. However, the preparation process of the existing technology is complicated, the environmental pollution is large, and it is not conducive to large-scale production.

[0031] e. Wide application: The hyperbranched prepolymer of the present invention can be used for UV-curable coatings, has excellent curing performance and physical properties, and can be widely used in coatings, adhesives, plastics and other industries, with broad application prospects. However, the acrylic resin and polyurethane elastomer prepared by existing technology are limited in application scope. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Embodiment 1:

[0034] 150.0g of butyl acetate was added to a 500ml three-necked flask, and stirring was started. The stirring rate was controlled to be (300-400)r / min, and the temperature was slowly raised. When the system temperature reached (115-120)℃, a mixed solution containing 41.3g of G06C, 2.5g of HDDA, 3.0g of ETPTA, 2.7g of HEMA, and 1.1g of GTP was slowly added at a dropping rate of 0.35mL / min. After the addition was completed, and after stirring at the same temperature for 30min, 0.4g of AIBN was added and stirred continuously. The mixture was kept warm for 3h. After the insulation was completed, the temperature was lowered to (50-60)℃, and then 3.3g of MOI was added dropwise. After the addition was completed, the mixture was kept warm for 2h, and then the temperature was raised to 80℃ for distillation. When the distillate no longer dripped out, the distillation was stopped, and the temperature was lowered to discharge the material to obtain a colorless hyperbranched prepolymer.

[0035] Weigh 10.0 g of hyperbranched prepolymer, 1.5 g of active diluent G06C, and 0.115 g of photoinitiator 1173 in a disposable cup, stir evenly, let stand for 10 min, pour the mixed solution onto a glass plate and level it, then irradiate it with a handheld UV lamp, irradiate the front side for 17 s and irradiate the back side for 17 s to obtain a UV-cured coating.

[0036] Embodiment 2:

[0037] 150.0g of butyl acetate was added to a 500ml three-necked flask, and stirring was started. The stirring rate was controlled to be (300-400)r / min, and the temperature was slowly raised. When the system temperature reached (115-120)°C, a mixed solution containing 41.3g of G06C, 5.5g of TMPTA, 2.7g of HEMA, and 1.1g of GTP was slowly added at a dropping rate of 0.35mL / min. After the addition was completed, and after stirring at the same temperature for 30min, 0.4g of BPO was added and stirred continuously. The mixture was kept warm for 3h. After the insulation was completed, the temperature was lowered to (50-60)°C, and then 3.3g of MOI was added dropwise. After the addition was completed, the mixture was kept warm for 2h, and then the temperature was raised to 80°C for distillation. When the distillate no longer dripped out, the distillation was stopped, and the temperature was lowered to discharge the material to obtain a colorless hyperbranched prepolymer.

[0038] Weigh 10.0 g of hyperbranched prepolymer, 1.5 g of active diluent G06C, and 0.115 g of photoinitiator 1173 in a disposable cup, stir evenly, let stand for 10 min, pour the mixed solution onto a glass plate and level it, then irradiate it with a handheld UV lamp, irradiate the front side for 15 s and the back side for 15 s to obtain a UV-cured coating.

[0039] Embodiment 3:

[0040] 150.0g of trifluorotoluene was added to a 500ml three-necked flask, and stirring was started. The stirring rate was controlled to be (300-400)r / min, and the temperature was slowly raised. When the system temperature reached (115-120)℃, a mixed solution containing 41.3g of G06C, 5.5g of DTMPTTA, 2.7g of HEMA, and 1.1g of DK-08 was slowly added at a dropping rate of 0.35mL / min. After the addition was completed, and after stirring at the same temperature for 30min, 0.4g of AIBN was added and stirred continuously. The mixture was kept warm for 3h. After the insulation was completed, the temperature was lowered to (50-60)℃, and then 3.3g of MOI was added dropwise. After the addition was completed, the mixture was kept warm for 2h, and then the temperature was raised to 80℃ for distillation. When the distillate no longer dripped out, the distillation was stopped, and the temperature was lowered to discharge the material to obtain a colorless hyperbranched prepolymer.

[0041] Weigh 10.0 g of hyperbranched prepolymer, 1.5 g of active diluent G06C, and 0.115 g of photoinitiator 1173 in a disposable cup, stir evenly, let stand for 10 min, pour the mixed solution onto a glass plate and level it, then irradiate it with a handheld UV lamp, irradiate the front side for 17 s and irradiate the back side for 17 s to obtain a UV-cured coating.

[0042] Embodiment 4:

[0043] 150.0g of trifluorotoluene was added to a 500ml three-necked flask, and stirring was started. The stirring rate was controlled to be (300-400)r / min, and the temperature was slowly raised. When the system temperature reached (115-120)℃, a mixed solution containing 41.3g of G06C, 5.5g of DPHA, 2.7g of HEMA, and 1.1g of DK-08 was slowly added at a dropping rate of 0.35mL / min. After the addition was completed, and after stirring at the same temperature for 30min, 0.4g of AIBME was added and stirred continuously. The mixture was kept warm for 3h. After the insulation was completed, the temperature was lowered to (50-60)℃, and then 3.3g of MOI was added dropwise. After the addition was completed, the mixture was kept warm for 2h, and then the temperature was raised to 80℃ for distillation. When the distillate no longer dripped out, the distillation was stopped, and the temperature was lowered to discharge the material to obtain a colorless hyperbranched prepolymer.

[0044] Weigh 10.0 g of hyperbranched prepolymer, 1.5 g of active diluent G06C, and 0.115 g of photoinitiator 1173 in a disposable cup, stir evenly, let stand for 10 min, pour the mixed solution onto a glass plate and level it, then irradiate it with a handheld UV lamp, irradiate the front side for 18 s and the back side for 18 s to obtain a UV-cured coating.

[0045] Comparative Example

[0046] Weigh 10.0g of existing resin, 5g of active diluent G06C, and 0.115g of photoinitiator 1173 in a disposable cup, stir evenly, let stand for 10 minutes, pour the mixed solution onto a glass plate and level it, then irradiate it with a handheld UV lamp, irradiate the front side for 30s and the back side for 30s to obtain a UV-cured coating.

[0047] Technical Effects of the Invention

[0048] The performance test results of the UV-curing coatings prepared by using the hyperbranched prepolymer of the present invention and the UV-curing coatings prepared by using the existing resins are shown in the following table.

[0049] Resin Viscosity (mPa.s) Light curing time(s) Amount of diluent used (g) Tensile strength(MPa) Existing resin 4000 60 5 3.28 Example 1 3000 34 1.5 3.72 Example 2 2900 30 1.5 3.57 Example 3 3200 34 1.5 4.20 Example 4 3300 36 1.5 4.37

[0050] Due to the advanced nature of the technical solution, it can be widely used in the application fields such as the field of coating preparation, the field of ultraviolet light curing technology and the field of polymer chemistry. In the field of coating preparation, hyperbranched prepolymers can be used as the base resin of coatings due to their low viscosity and high molecular weight, and are particularly suitable for ultraviolet light curing coatings. Traditional ultraviolet light curing coatings need to add a large amount of diluents to reduce viscosity during the synthesis process, which not only causes waste of resources but also pollutes the environment. However, due to their highly branched molecular structure, the molecules of hyperbranched prepolymers are not easy to entangle, the viscosity is low, and they contain a large number of external active end groups and internal cavity structures. They can effectively reduce the viscosity of ultraviolet light curing coatings, reduce the amount of organic solvents, reduce the degree of environmental pollution, and improve curing efficiency and coating performance. In the field of ultraviolet light curing technology, hyperbranched prepolymers, as a new type of photocurable material, have excellent photocuring properties. Because they contain a large number of double bond groups, they can be rapidly cured under ultraviolet light to form a coating with excellent mechanical properties and weather resistance. In addition, due to its highly branched molecular structure, hyperbranched prepolymers are not prone to crosslinking during the curing process, which can effectively avoid problems such as shrinkage and cracking of the coating caused by crosslinking, and improve the stability and service life of the coating. In the field of polymer chemistry, the preparation method of hyperbranched prepolymers provides new ideas and methods for the study of polymer chemistry. Traditional polymer preparation methods are mainly through condensation reactions of free radical polymerization or step-by-step polymerization. The polymers prepared by these methods usually have a linear molecular structure, a small molecular weight, a high viscosity, and are not easy to use. However, due to its highly branched molecular structure, hyperbranched polymers have a large molecular weight, a low viscosity, and are easy to process and use, providing new directions and possibilities for the study of polymer chemistry. In general, the preparation method and application prospects of hyperbranched prepolymers are broad, the market demand is large, and they have important application value and commercial potential.

[0051] The present disclosure has been described by the above-mentioned relevant embodiments, but the above-mentioned embodiments are only examples for implementing the present disclosure. It must be pointed out that the disclosed embodiments do not limit the scope of the present disclosure. On the contrary, changes and modifications made without departing from the spirit and scope of the present disclosure are all within the scope of patent protection of the present disclosure.

Claims

1. A hyperbranched prepolymer, characterized in that: By mass percentage, it is composed of the following components: The monomers are composed of a multifunctional monomer: a monomer containing a hydroxyl group: an isocyanate monomer having an isocyanate group at one end and a double bond group at the other end, in a mass ratio of 15-20:1:1-1.

5.

2. The hyperbranched prepolymer according to claim 1, characterized in that: The multifunctional monomer is one or more of tridecafluorooctyl acrylate, 1,6-hexanediol diacrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, di(trimethylolpropane) tetraacrylate, and polydipentaerythritol hexaacrylate.

3. The hyperbranched prepolymer according to claim 1, characterized in that: The monomer containing a hydroxyl group is hydroxyethyl methacrylate.

4. The hyperbranched prepolymer according to claim 1, characterized in that: The linear isocyanate monomer having an isocyanate group at one end and a double bond group at the other end is methacrylate isocyanate.

5. The hyperbranched prepolymer according to claim 1, characterized in that: The initiator is one or more of benzoyl peroxide, azobisisobutyronitrile and dimethyl azobisisobutyrate.

6. The hyperbranched prepolymer according to claim 1, characterized in that: The chain transfer agent is one or more of GTP and DK-08.

7. The hyperbranched prepolymer according to claim 1, characterized in that: The solvent is one or more of butyl acetate and trifluorotoluene.

8. A method for preparing a hyperbranched prepolymer according to any one of claims 1 to 7, characterized in that: The following steps are involved: Weigh the solvent according to the formula amount and add it into a three-necked flask, start stirring, control the stirring rate to 300-400r / min, and start to slowly heat up. When the system temperature reaches 115-120°C, slowly add the mixed solution of multifunctional monomer, hydroxyl-containing monomer and chain transfer agent. After the addition is completed, stir at this temperature for 30 minutes, add the initiator and keep stirring, keep the reaction for 3 hours, after the insulation is completed, cool to 50-60°C, and then add a linear isocyanate monomer containing an isocyanate group at one end and a double bond group at the other end. After the addition is completed, keep the reaction for 2 hours, then heat to 80°C for distillation. When the distillate stops dripping, stop the distillation, cool and discharge, and obtain a hyperbranched prepolymer.

9. A UV-curable coating, characterized in that: The invention comprises a hyperbranched prepolymer as claimed in any one of claims 1 to 7, and is composed of the following components in terms of mass percentage: Hyperbranched prepolymer 70~87% Active diluent 12~28% Photoinitiator 0.8~2% The active diluent is tridecafluorooctyl acrylate, and the photoinitiator is 2-hydroxy-2-methyl-1-phenylpropanone.

10. A method for preparing the UV-curable coating according to claim 9, characterized in that: The method comprises the following steps: weighing hyperbranched prepolymer, active diluent and photoinitiator for ultraviolet light curing coating respectively according to the formula amount, stirring them evenly in a disposable cup, and then obtaining ultraviolet light curing coating.

Images