Method for preparing GMA type acrylic resin for powder coating in biomass solvent

Abstract

The invention relates to a method for preparing GMA (glycidyl methacrylate) type acrylic resin for powder coating in a biomass solvent, which is characterized in that in the biomass solvent, alkyl (meth) acrylate monomer, glycidyl methacrylate and styryl monomer are used as raw materials, and under the action of an initiator and a chain transfer agent, the GMA type acrylic resin for powder coating is prepared. The biomass solvent is used for replacing a traditional organic solvent and participates in synthesis of the GMA type acrylic powder coating resin, and green preparation of the GMA type acrylic resin is achieved; the epoxy equivalent of the obtained GMA type acrylic resin is 510-590 g / equivalent, the glass transition temperature is 35-50 DEG C, the weight-average molecular weight is 4000-13000, and the molecular weight distribution is 1.3-1.5; the obtained GMA type acrylic resin is used in the powder coating, the effect can meet the standard requirements of commercially available powder coating film-forming resin, and the coating has good impact resistance and adhesive force.

Description

Technical Field

[0001] The invention belongs to the technical field of acrylic resin powder coatings, and in particular relates to a method for preparing a GMA type acrylic resin for powder coatings in a biomass solvent. Background Art

[0002] GMA type acrylic resin powder coating has good color and gloss retention, excellent weather resistance and adhesion, and is suitable for large-area outdoor coating. It is widely used in the coating of doors and windows, office furniture, kitchen and bathroom products, and is also very popular in the automotive field.

[0003] As people's awareness of environmental protection gradually increases and the government's restrictions on volatile organic compound emission standards continue to tighten, powder coatings are gradually leaning towards green production. However, at present, most of the preparation of GMA acrylic resins still uses traditional petroleum-based organic solvents, such as toluene and xylene, which easily release toxic and harmful gases during the production process, endangering environmental health.

[0004] The present invention innovatively adopts biomass solvents to replace traditional organic solvents in the preparation of GMA type acrylic resin powder coatings, which not only complies with the national call for green production, but is also an attempt at green production of powder coatings and has great commercial potential. Summary of the invention

[0005] The purpose of the present invention is to use biomass solvents instead of traditional organic solvents to prepare GMA type acrylic resin for powder coating (GMA type acrylic powder coating resin); the GMA type acrylic resin obtained by the route of the present invention is used in powder coating, which can meet the standard requirements of commercially available powder coating film-forming resins, and the coating has good impact resistance and adhesion, thereby realizing the green preparation of GMA type acrylic resin.

[0006] The technical solution adopted by the present invention is:

[0007] A method for preparing a GMA type acrylic resin for powder coating in a biomass solvent comprises the following steps:

[0008] (1) adding a biomass solvent to a reactor and removing oxygen by bubbling with nitrogen, stirring and heating to 100-140° C., uniformly mixing alkyl (meth)acrylate monomer, glycidyl methacrylate, styrene-based monomer, initiator and chain transfer agent, and slowly dropping them into a reaction container after deoxygenation by bubbling with nitrogen, and reacting for 0.5 h to 1.5 h after the addition is completed;

[0009] (2) Continue to add the remaining initiator and the mixed solution of biomass solvent, complete the addition within 10 minutes, and react for 1.5 hours to 2.5 hours;

[0010] (3) After the reaction is completed, the solvent is removed by distillation under reduced pressure. When the temperature of the reaction system reaches 170-190°C, the reaction is kept for 1.5-2.5 hours, and then the vacuum is released and the material is discharged for cooling.

[0011] The invention uses (meth) alkyl acrylate monomer, glycidyl methacrylate and styrene monomer as raw materials in a biomass solvent and prepares GMA acrylic resin under the action of an initiator and a chain transfer agent.

[0012] Preferably, the (meth)acrylic acid alkyl ester monomer, methacrylate glycidyl ester and styrene-based monomer are raw materials, wherein the mass fraction of the (meth)acrylic acid alkyl ester monomer is 50-60%, the mass fraction of methacrylate glycidyl ester is 25-30% and the mass fraction of the styrene-based monomer is 15-20%.

[0013] Preferably, the biomass solvent is any one of ethyl lactate, γ-valerolactone, levulinic acid, 2-methyltetrahydrofuran, dimethyl isosorbide, 2,5-dimethylfuran, ethoxymethylfurfural, dihydro-levulinic ketone, 1,4-pentanediol, alkyl levulinate, 4-isopropyltoluene, and diethyl succinate; and the biomass solvent accounts for 60 to 100% of the total mass of the raw material.

[0014] Preferably, the (meth)acrylic acid alkyl ester monomer is one or more of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, isobutyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate, cyclohexyl acrylate, isobornyl acrylate, benzyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, cyclohexyl methacrylate, dimethylaminoethyl methacrylate, isobornyl methacrylate, and dimethylaminoethyl methacrylate, mixed in any proportion.

[0015] Preferably, the styrene-based monomer is one of methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene and octylstyrene.

[0016] Preferably, the initiator is one of dibenzoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, 1,1-di-tert-butyl peroxycyclohexane, tert-butyl peroxybenzoate, 2,5-di-tert-butyl peroxy-2,5-dimethylhexane, and di-tert-butyl peroxide.

[0017] Preferably, the initiator accounts for 3-8% of the total weight of the raw materials.

[0018] Preferably, the chain transfer agent is one of isobutyl acrylate, n-dodecyl mercaptan, and α-methylstyrene dimer.

[0019] Preferably, the chain transfer agent accounts for 0.05-0.2% of the total weight of the raw materials.

[0020] Preferably, the epoxy equivalent of the prepared GMA type acrylic resin is 510-590 g / equivalent, the glass transition temperature is 35-50° C., the number average molecular weight is 4000-13000, and the molecular weight distribution is 1.3-1.5.

[0021] The beneficial effects of the present invention are:

[0022] (1) The present invention adopts biomass solvents to replace traditional toxic and harmful solvents. The GMA-type acrylic resin for powder coatings prepared using biomass solvents has similar performance characteristics to commercially available powder coatings. The resin obtained by the present invention not only does not emit VOCs during use such as spraying, but also does not emit VOCs during the production process. This makes powder coatings an environmentally friendly coating option, which helps to reduce air pollution and the impact on human health.

[0023] (2) The present invention uses biomass solvents instead of traditional organic solvents to participate in the synthesis of GMA type powder coating resins, thereby realizing the green preparation of GMA type acrylic resins; the epoxy equivalent of the obtained GMA type acrylic powder coating resin is 510-590 g / equivalent, the glass transition temperature is 35-50° C., the number average molecular weight is 4000-13000, and the molecular weight distribution is 1.3-1.5; the obtained GMA type acrylic resin is used in powder coatings, and the effect can meet the standard requirements of commercially available powder coating film-forming resins, and the coating has good impact resistance and adhesion. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure is the nuclear magnetic spectrum of the GMA type powder coating acrylic resin prepared by the present invention. DETAILED DESCRIPTION

[0025] The technical scheme of the present invention is further specifically described below through examples, which are provided for the purpose of explaining the present invention, not for limiting the present invention. Based on the examples in this application, all other examples obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0026] The experimental methods described in the examples are conventional methods unless otherwise specified; the percentages involved are weight percentages unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0027] Example 1

[0028] Preparation of GMA-type acrylic powder coating resin in ethyl lactate

[0029] Specific implementation steps:

[0030] Step 1: Add 340g of ethyl lactate to a pressure-resistant reactor and remove oxygen by nitrogen bubbling, and heat and stir to 120°C. Mix 150g of styrene, 340g of methyl methacrylate, 225g of butyl acrylate, 285g of glycidyl methacrylate, 50g of tert-butyl peroxide (2-ethylhexanoate), 1g of n-dodecyl mercaptan and 630g of ethyl lactate, and add dropwise to the pressure-resistant reactor after nitrogen bubbling to remove oxygen, and react for 1h after the addition is completed;

[0031] Step 2: Continue to add a mixture of 5 g of tert-butyl peroxy (2-ethylhexanoate) and 30 g of ethyl lactate, dropwise within 10 min, and react for 2 h;

[0032] Step 3: After the reaction is completed, start to distill under reduced pressure to remove the solvent. When the temperature of the reaction system reaches 180°C, stay for 0.5h, then release the vacuum and discharge the material for cooling.

[0033] The epoxy equivalent of the obtained GMA type acrylic powder coating resin is 531 g / equivalent, the number average molecular weight is 8600, the molecular weight distribution is 1.41, and the Tg is 40.91°C.

[0034] Figure 1 This is the nuclear magnetic resonance image of the polymerization product GMA type acrylic powder coating resin of the present invention, showing the structure of the prepared GMA type acrylic powder coating resin. It can be clearly seen from this image that each polymerization monomer participates in the polymerization.

[0035] The NMR spectrum of the GMA type powder coating acrylic resin prepared by the present invention is as follows: Figure 1 As shown; Figure 1 The structure of the prepared GMA type acrylic powder coating resin is shown. It can be clearly seen from the figure that each polymerization monomer participates in the polymerization.

[0036] Example 2

[0037] Specific implementation steps for the preparation of GMA type acrylic powder coating resin in γ-valerolactone:

[0038] Step 1: Add 340g of γ-valerolactone to a pressure-resistant reactor and remove oxygen by bubbling with nitrogen, and heat and stir to 120°C. Mix 150g of styrene, 370g of methyl methacrylate, 195g of butyl acrylate, 285g of glycidyl methacrylate, 50g of tert-butyl peroxide (2-ethylhexanoate), 1g of n-dodecyl mercaptan and 630g of γ-valerolactone, remove oxygen by bubbling with nitrogen, and then add dropwise to the pressure-resistant reactor. After the addition is completed, react for 1h;

[0039] Step 2: Continue to add a mixture of 5 g of tert-butyl peroxy (2-ethylhexanoate) and 30 g of γ-valerolactone, complete the addition within 10 min, and react for 2 h;

[0040] Step 3: After the reaction is completed, start to distill under reduced pressure to remove the solvent. When the temperature of the reaction system reaches 180°C, stay for 0.5h, then release the vacuum and discharge the material for cooling.

[0041] The epoxy equivalent of the obtained GMA type acrylic powder coating resin is 515 g / equivalent, the number average molecular weight is 7013, the molecular weight distribution is 1.43, and the Tg is 43.38°C.

[0042] Example 3

[0043] Preparation of GMA-type acrylic powder coating resin in levulinic acid

[0044] Specific implementation steps:

[0045] Step 1: Add 340g of levulinic acid to a pressure-resistant reactor and remove oxygen by bubbling with nitrogen, and heat and stir to 120°C. Mix 150g of styrene, 340g of methyl methacrylate, 225g of butyl acrylate, 285g of glycidyl methacrylate, 50g of tert-butyl peroxide (2-ethylhexanoate), 1g of n-dodecyl mercaptan and 630g of levulinic acid, remove oxygen by bubbling with nitrogen, and then add dropwise to the pressure-resistant reactor. After the addition is completed, react for 1h;

[0046] Step 2: Continue to add a mixture of 5 g of tert-butyl peroxide (2-ethylhexanoate) and 30 g of levulinic acid, dropwise within 10 min, and react for 2 h;

[0047] Step 3: After the reaction is completed, start to distill under reduced pressure to remove the solvent. When the temperature of the reaction system reaches 180°C, stay for 0.5h, then release the vacuum and discharge the material for cooling.

[0048] The epoxy equivalent of the obtained GMA type acrylic powder coating resin is 545 g / equivalent, the number average molecular weight is 5600, the molecular weight distribution is 1.41, and the Tg is 40.62°C.

[0049] Example 4

[0050] Preparation of GMA-type acrylic powder coating resin in 2-methyltetrahydrofuran

[0051] Specific implementation steps:

[0052] Step 1: Add 340g of 2-methyltetrahydrofuran to a pressure-resistant reactor and remove oxygen by bubbling with nitrogen, and heat and stir to 120°C. Mix 150g of styrene, 370g of methyl methacrylate, 195g of butyl acrylate, 285g of glycidyl methacrylate, 50g of tert-butyl peroxide (2-ethylhexanoate), 1g of n-dodecyl mercaptan and 630g of 2-methyltetrahydrofuran, and add dropwise to the pressure-resistant reactor after deoxygenation by bubbling with nitrogen, and react for 1h after the addition is completed;

[0053] Step 2: Continue to add a mixture of 5 g of tert-butyl peroxy (2-ethylhexanoate) and 30 g of 2-methyltetrahydrofuran, dropwise within 10 min, and react for 2 h;

[0054] Step 3: After the reaction is completed, start to distill under reduced pressure to remove the solvent. When the temperature of the reaction system reaches 180°C, stay for 0.5h, then release the vacuum and discharge the material for cooling.

[0055] The epoxy equivalent of the obtained GMA type acrylic powder coating resin is 538 g / equivalent, the number average molecular weight is 6103, the molecular weight distribution is 1.45, and the Tg is 40.78°C.

[0056] Example 5

[0057] The specific implementation steps for the preparation of GMA type acrylic powder coating resin in 2,5-dimethylfuran are as follows:

[0058] Step 1: Add 340g of 2,5-dimethylfuran to a pressure-resistant reactor and remove oxygen by bubbling with nitrogen, and heat and stir to 120°C. Mix 170g of styrene, 440g of methyl methacrylate, 150g of butyl acrylate, 285g of glycidyl methacrylate, 50g of tert-butyl peroxide (2-ethylhexanoate), 1g of n-dodecyl mercaptan and 630g of 2,5-dimethylfuran, and add dropwise to the pressure-resistant reactor after deoxygenation by bubbling with nitrogen, and react for 1h after the addition is completed;

[0059] Step 2: Continue to add a mixture of 5 g of tert-butyl peroxy (2-ethylhexanoate) and 30 g of 2,5-dimethylfuran, dropwise within 10 min, and react for 2 h;

[0060] Step 3: After the reaction is completed, start to distill under reduced pressure to remove the solvent. When the temperature of the reaction system reaches 180°C, stay for 0.5h, then release the vacuum and discharge the material for cooling.

[0061] The epoxy equivalent of the obtained GMA type acrylic powder coating resin was 555 g / equivalent, the number average molecular weight was 6100, the molecular weight distribution was 1.39, and the Tg was 52.7°C.

[0062] Comparative Example 1

[0063] Preparation of GMA-type acrylic powder coating resin in xylene

[0064] Specific implementation steps:

[0065] Step 1: Add 340g xylene to the pressure reactor and remove oxygen by nitrogen bubbling, and heat and stir to 120°C. Mix 150g styrene, 370g methyl methacrylate, 195g butyl acrylate, 285g glycidyl methacrylate, 50g tert-butyl peroxide (2-ethylhexanoate), 1g n-dodecyl mercaptan and 630g butyl acetate, and add dropwise to the pressure reactor after nitrogen bubbling to remove oxygen, and react for 1h after the addition is completed;

[0066] Step 2: Continue to add a mixture of 5 g of tert-butyl peroxy (2-ethylhexanoate) and 30 g of xylene, and complete the addition within 10 min. React for 2 h.

[0067] Step 3: After the reaction is completed, start to distill under reduced pressure to remove the solvent. When the temperature of the reaction system reaches 180°C, stay for 0.5h, then release the vacuum and discharge the material for cooling.

[0068] The epoxy equivalent of the obtained GMA type acrylic powder coating resin is 599 g / equivalent, the number average molecular weight is 7730, the molecular weight distribution is 1.69, and the Tg is 40.65°C.

[0069] Performance comparison

[0070] The samples (unit / g) prepared in Examples 1-5 and Comparative Example 1 were made into powder coatings for application, and the samples to be tested were prepared according to the formula in Table 1;

[0071] Table 1: Preparation of formulations for application examples 1-6

[0072] Application Example 1 Application Example 2 Application Example 3 Application Example 4 Application Example 5 Application Example 6 <![CDATA[Dodecanedioic acid 1 > 200 200 200 200 200 Example 1 800 Example 2 800 Example 3 800 Example 4 800 Example 5 800 Comparative Example 1 800 <![CDATA[K7562 2 ]]> 16 16 16 16 16 16 Benzoin 4 4 4 4 4 4 total 1020 1020 1020 1020 1020 1020

[0073] 1. Curing agent, Shandong Guohua Chemical;

[0074] 2. Leveling agent, Lu'an Jietongda New Materials Co., Ltd.

[0075] The prepared samples were tested.

[0076] The test method is as follows:

[0077] Appearance: Evaluate by visual inspection. Mainly observe whether there are orange peel, pores and other problems on the surface, whether the paint film surface is flat, etc.

[0078] Adhesion: Determined by the GB / T 9286-1998 hundred grid method. The grade is 0-5, where 0 is excellent and 5 is poor.

[0079] Curing temperature: The powder curing process is 150℃~180℃, which is normal curing.

[0080] Leveling performance: Leveling performance is rated according to the leveling effect rating standard board of the US PCI, 1 for poor and 10 for excellent.

[0081] Impact performance: measured with Kunshan Sannuo Instruments paint film impact tester QCJ-1m according to GB / T 1732-1993. Observe the cracks, wrinkles, peeling and other phenomena of the paint film during positive and negative impacts, and make an assessment.

[0082] The test results are recorded. The performance test results of application examples 1-6 are shown in Table 2 below:

[0083] Table 2 Performance test results of application examples 1-6

[0084]

[0085]

[0086] From the test results in Table 2, it can be seen that compared with Application Example 6 (Comparative Example 1), Application Examples 1-5 can achieve the performance of the resin prepared by the present invention. The performance can not only reach the numerical performance obtained by the traditional solvent preparation, but also shows certain advantages in adhesion and impact resistance.

[0087] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a GMA type acrylic resin for powder coating in a biomass solvent, characterized in that The steps include: (1) adding a biomass solvent to a reactor and removing oxygen by bubbling with nitrogen, stirring and heating to 100-140° C., uniformly mixing alkyl (meth)acrylate monomer, glycidyl methacrylate, styrene-based monomer, initiator and chain transfer agent, and slowly dropping them into a reaction container after deoxygenation by bubbling with nitrogen, and reacting for 0.5 h to 1.5 h after the addition is completed; (2) Continue to add the remaining initiator and the mixed solution of biomass solvent, complete the addition within 10 minutes, and react for 1.5 hours to 2.5 hours; (3) After the reaction is completed, the solvent is removed by distillation under reduced pressure. When the temperature of the reaction system reaches 170-190°C, the reaction is kept for 1.5-2.5 hours, and then the vacuum is released and the material is discharged for cooling.

2. The method for preparing GMA type acrylic resin for powder coating in biomass solvent according to claim 1, characterized in that: The (meth)acrylic acid alkyl ester monomer, methacrylate glycidyl ester and styrene-based monomer are raw materials, wherein the mass fraction of the (meth)acrylic acid alkyl ester monomer is 50-60%, the mass fraction of methacrylate glycidyl ester is 25-30% and the mass fraction of styrene-based monomer is 15-20%.

3. The method for preparing GMA type acrylic resin for powder coating in biomass solvent according to claim 2, characterized in that: The biomass solvent is any one of ethyl lactate, γ-valerolactone, levulinic acid, 2-methyltetrahydrofuran, dimethyl isosorbide, 2,5-dimethylfuran, ethoxymethylfurfural, dihydro-levoglucose ketone, 1,4-pentanediol, alkyl levulinate, 4-isopropyltoluene and diethyl succinate; the biomass solvent accounts for 60-100% of the total mass of the raw material.

4. The method for preparing GMA type acrylic resin for powder coating in biomass solvent according to claim 2, characterized in that: The (meth)acrylic acid alkyl ester monomer is one or more of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, isobutyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate, cyclohexyl acrylate, isobornyl acrylate, benzyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, cyclohexyl methacrylate, dimethylaminoethyl methacrylate, isobornyl methacrylate, and dimethylaminoethyl methacrylate, mixed in any proportion.

5. The method for preparing GMA type acrylic resin for powder coating in biomass solvent according to claim 2, characterized in that: The styrene-based monomer is one of methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene and octylstyrene.

6. The method for preparing GMA type acrylic resin for powder coating in biomass solvent according to claim 2, characterized in that: The initiator is one of dibenzoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, 1,1-di-tert-butyl peroxycyclohexane, tert-butyl peroxybenzoate, 2,5-di-tert-butyl peroxy-2,5-dimethylhexane, and di-tert-butyl peroxide.

7. The method for preparing GMA type acrylic resin for powder coating in biomass solvent according to claim 6, characterized in that: The initiator accounts for 3-8% of the total weight of the raw materials.

8. The method for preparing GMA type acrylic resin for powder coating in biomass solvent according to claim 2, characterized in that: The chain transfer agent is one of isobutyl acrylate, n-dodecyl mercaptan and α-methylstyrene dimer.

9. The method for preparing GMA type acrylic resin for powder coating in biomass solvent according to claim 8, characterized in that: The chain transfer agent accounts for 0.05-0.2% of the total weight of the raw materials.

10. The method for preparing GMA type acrylic resin for powder coating in biomass solvent according to claim 2, characterized in that: The epoxy equivalent of the prepared GMA type acrylic resin is 510-590 g / equivalent, the glass transition temperature is 35-50 DEG C, the number average molecular weight is 4000-13000, and the molecular weight distribution is 1.3-1.5.

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