目的 为实现硅钢卷材表面的自黏结涂层在固化过程中黏结性能的精确控制,探索一种半定量评价其预固化（B态）程度的方法,并明确其与最终表面涂层性能的关联。方法 以水性环氧树脂体系的自黏结涂层为对象,通过在不同温度（180、190、240 ℃）、不同时间（0.5~6 min）工艺条件下烘烤制备B态样品,采用差示扫描量热法（DSC）分析其残余反应焓（ΔHr）,并基于总反应焓ΔHT（82.07 J/g）计算相对固化度（α）。结果 结果表明,随加热温度升高或时间延长,涂层残余焓ΔHr显著下降,固化度α相应提升;进一步将B态样品热压至终态（C态）并测试其辊动剥离强度,涂层性能与固化程度之间存在最佳工艺窗口,当残余焓ΔHr处于20~50 J/g区间（对应固化度α为35%~75%）时,涂层表现出最优的综合性能,其黏结强度≥3 N/mm且能有效控制溢胶。结论 涂层残余焓ΔHr、固化度α与B态涂层加热温度、时间等工艺参数存在明显的相关性,将涂层残余焓ΔHr、固化度α控制在合适范围时可获得较好的涂层性能;DSC分析法用于表征自黏结涂层的固化程度具备一定的可行性。
Abstract
Silicon steel with self-bonding coatings is a core material for high-end motors in emerging fields such as new energy vehicle drive motors, UAV motors, and humanoid robot joint motors, as it enables excellent interlaminar bonding and insulation performance. However, the self-bonding coating, mainly composed of epoxy resin, undergoes a phased curing process: initial State A (wet coating), intermediate State B (coated steel coils delivered by steel plants), and final State C (bonded laminated iron cores). The cross-linking reaction kinetics between epoxy groups and curing agents are complex, making it extremely difficult to control and quantify the pre-curing degree of State B. These issues have been limiting the research on the correlation between curing degree and coating performance, failing to support the optimization of production processes and the stable control of product quality. To address these problems, the work aims to investigate the curing degree of the self-bonding coating in State B through differential scanning calorimetry (DSC) and establish its relationship with key coating properties. Firstly, the silicon steel self-bonding coating was prepared by blending a water-based bisphenol A/F epoxy emulsion with amine curing agents and co-solvents. An uncoated annealed substrate of grade B25AV1300 was cleaned with anhydrous ethanol, and the prepared self-bonding coating was uniformly applied to its surface, with the average dry film thickness of each surface controlled at 2.5 μm. A series of State B samples were fabricated by baking the coated substrates under three temperature gradients (180 ℃, 190 ℃, 240 ℃) and a time gradient (0.5-6 min). For the preparation of State C samples, the State B samples were cut into pieces, stacked, and then subjected to final curing with an RYJ-600ZG2 automatic hot press under the conditions of 200 ℃, 3 MPa, and 30 min. To characterize the curing degree of the State B coating, a Mettler Toledo DSC3 differential scanning calorimeter was used to test the residual reaction enthalpy (ΔHr) of the coating powder scraped from State B samples. The relative curing degree (α) was calculated with the formula: α=[(ΔHT-ΔHr)/ΔHT]×100%. Additionally, the bonding strength of State C samples was tested via the rolling peel method in accordance with the GB/T 7122 standard, with a Zwick/Roell Z150 tensile machine at a testing speed of 100 mm/min, and the glue overflow of the coating was simultaneously observed. The results showed that with the increase in baking temperature or extension of baking time, the curing exothermic peak in the DSC curve of the State B coating gradually flattened, the residual reaction enthalpy (ΔHr) decreased significantly, and the relative curing degree (α) increased continuously. The bonding strength of the State C coating was not simply linearly correlated with ΔHr and α but exhibited an optimal range: when the ΔHr of the State B coating was 20-50 J/g (corresponding to an α of approximately 35%-75%), the rolling peel strength of the State C samples was ≥ 3 N/mm, and the glue overflow was effectively controlled. This work confirms that differential scanning calorimetry (DSC), which calculates the relative curing degree (α) by testing the residual reaction enthalpy (ΔHr), is technically feasible for effectively characterizing the curing degree of the self-bonding coating on silicon steel in State B. The ΔHr and α of the State B coating show significant correlations with baking temperature and time, but they need to meet a specific matching relationship with the coating bonding strength to achieve excellent performance.
关键词
自黏结涂层 /
硅钢 /
固化程度 /
DSC分析 /
黏结强度
Key words
self-bonding coating /
silicon steel /
curing degree /
DSC analysis /
bonding strength
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参考文献
[1] XIA C J, WANG H Z, WU Y, et al.Joining of the Laminated Electrical Steels in Motor Manufacturing: A Review[J]. Materials, 2020, 13(20): 4583.
[2] 仇圣桃, 牛宇豪, 乔家龙, 等. 驱动电机用无取向硅钢开发与性能调控研究综述[J]. 安徽工业大学学报(自然科学版), 2024, 41(4): 350-364.
QIU S T, NIU Y H, QIAO J L, et al.A Review of Development and Performance Control of Non-Oriented Silicon Steel for Drive Motors[J]. Journal of Anhui University of Technology (Natural Science), 2024, 41(4): 350-364.
[3] KIM S S, LEE J H, LEE M, et al.A Study on the Manufacturing Characteristics of New Materials for Electric Vehicle Drive Motor[J]. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 2024, 46(9): 577.
[4] KAIDO C, TAKEDA K, WAKISAKA T, et al.Characteristics of Adhesive Coating Non-Oriented Electrical Steel Sheet Cores[J]. IEEJ Transactions on Industry Applications, 1999, 119(7): 1010-1015.
[5] 陈卓. 薄规格和极薄/超薄硅钢发展态势研究[J]. 电工钢, 2024, 6(1): 46-51.
CHEN Z.Research on the Development Trend of Thin Gauge and Very-Thin/Ultra-Thin Gauge Electrical Steel[J]. Electrical Steel, 2024, 6(1): 46-51.
[6] KAUSAR A.High Performance Epoxy/Polyester-Based Nanocomposite Coatings for Multipurpose Applications: A Review[J]. Journal of Plastic Film & Sheeting, 2020, 36(4): 391-408.
[7] KUWATA M, NOGAWA S, TAKAHASHI N, et al.Development of Mold-Core Type Gapped Iron-Core Reactor Using Adhesive Coated Electromagnetic Sheet[J]. IEEJ Transactions on Power and Energy, 2005, 125(12): 1223-1229.
[8] LI S C, CHEN D, YUAN Y H, et al.Influence of Flexible Molecular Structure on the Cryogenic Mechanical Properties of Epoxy Matrix and Carbon Fiber/Epoxy Composite Laminate[J]. Materials & Design, 2020, 195: 109028.
[9] CAPRICHO J C, FOX B, HAMEED N.Multifunctionality in Epoxy Resins[J]. Polymer Reviews, 2020, 60(1): 1-41.
[10] MOHAN P.A Critical Review: The Modification, Properties, and Applications of Epoxy Resins[J]. Polymer-Plastics Technology and Engineering, 2013, 52(2): 107-125.
[11] LIANG M Y, LIU X, LIU D, et al.A Review of the Curing Rate and Mechanical Properties of Epoxy Resin on Polymer Matrix Composites[J]. Journal of Polymer Research, 2024, 31(11): 337.
[12] POORNIMA V P, GEORGE J S, THOMAS S.The Effect of Polymeric Inclusions and Nanofillers on Cure Kinetics of Epoxy Resin: A Review[J]. Polymer Science, Series A, 2021, 63(6): 637-651.
[13] VIDIL T, TOURNILHAC F, MUSSO S, et al.Control of Reactions and Network Structures of Epoxy Thermosets[J]. Progress in Polymer Science, 2016, 62: 126-179.
[14] SHUNDO A, AOKI M, YAMAMOTO S, et al.Cross- Linking Effect on Segmental Dynamics of Well-Defined Epoxy Resins[J]. Macromolecules, 2021, 54(13): 5950-5956.
[15] DERISZADEH A, SHAHRAKI F, MOSTAFA L, et al.Epoxy/Phenolic Nanocomposite Based Adhesives: Non- Isothermal Cure Kinetic Study[J]. Results in Engineering, 2024, 24: 103312.
[16] 郭建国, 李登峰, 王波. 硅钢自黏结涂层的常规性能研究[J]. 电工材料, 2020(1): 13-16.
GUO J G, LI D F, WANG B.Study on the Conventional Properties of Self-Bonding Coating on Silicon Steel[J]. Electrical Engineering Materials, 2020(1): 13-16.
[17] TZIAMTZI C K, CHRISSAFIS K.Optimization of a Commercial Epoxy Curing Cycle via DSC Data Kinetics Modelling and TTT Plot Construction[J]. Polymer, 2021, 230: 124091.
[18] ROŞU D, CAŞCAVAL C N, MUSTĄTĂ F, et al. Cure Kinetics of Epoxy Resins Studied by Non-Isothermal DSC Data[J]. Thermochimica Acta, 2002, 383(1/2): 119-127.
[19] BILYEU B, BROSTOW W, MENARD K P.Characterization of Epoxy Curing Using High Heating Rate DSC[J]. Materials Research Innovations, 2006, 10(1): 119-128.
[20] VAN OVERBEKE E, DEVAUX J, LEGRAS R, et al.Raman Spectroscopy and DSC Determination of Conversion in DDS-Cured Epoxy Resin: Application to Epoxy-Copolyethersulfone Blends[J]. Applied Spectroscopy, 2001, 55(5): 540-551.
[21] 徐亚娟, 张俊红. 等温与非等温DSC法研究环氧树脂的固化动力学[J]. 热固性树脂, 2020, 35(4): 18-20.
XU Y J, ZHANG J H.Study on the Curing Kinetics of Epoxy Resin by Isothermal and Non-Isothermal DSC[J]. Thermosetting Resin, 2020, 35(4): 18-20.
[22] PUGSTALLER R, WALLNER G M, STRAUß B, et al.Temperature Dependent Fatigue Crack Growth in Electrical Steel Laminates with Μm-Thick Epoxy Layers[J]. Engineering Fracture Mechanics, 2022, 267: 108416.
[23] ZVETKOV V L.Comparative DSC Kinetics of the Reaction of DGEBA with Aromatic Diamines. II. Isothermal Kinetic Study of the Reaction of DGEBA with M-Phenylene Diamine[J]. Polymer, 2002, 43(4): 1069-1080.
[24] HARDIS R, JESSOP J L P, PETERS F E, et al. Cure Kinetics Characterization and Monitoring of an Epoxy Resin Using DSC, Raman Spectroscopy, and DEA[J]. Composites Part A: Applied Science and Manufacturing, 2013, 49: 100-108.
[25] JIA H L, ZHU Y D, YAN C, et al.Reliability Evaluation of a New Method Developed for DSC Curing Kinetic Model of Epoxy Resin[J]. Journal of Applied Polymer Science, 2023, 140(26): e53986.
[26] RABEARISON N, JOCHUM C, GRANDIDIER J C.A Cure Kinetics, Diffusion Controlled and Temperature Dependent, Identification of the Araldite LY556 Epoxy[J]. Journal of Materials Science, 2011, 46(3): 787-796.
[27] PUGSTALLER R, WALLNER G M.Development of a Fracture-Mechanics Based Fatigue Testing Method for Epoxy/Electrical Steel Laminates with Thin Adhesive Layer[J]. Engineering Fracture Mechanics, 2021, 258: 108045.
[28] CHU C W, CHENG C H, OBAYASHI K, et al.Effects of Curing Conditions on Adhesive and Fatigue Properties of Hydrogenated Epoxy Resins in Bulk State and Single- Lap-Joint Configuration[J]. International Journal of Adhesion and Adhesives, 2024, 132: 103690.
[29] SHUNDO A, YAMAMOTO S, TANAKA K.Network Formation and Physical Properties of Epoxy Resins for Future Practical Applications[J]. Journal of American Chemical Society, 2022, 2(7): 1522-1542.
[30] LI J, GUO P X, KONG X X, et al.Curing Degree Dependence of Dielectric Properties of Bisphenol-a- Based Epoxy Resin Cured with Methyl Hexahydrophthalic Anhydride[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2022, 29(6): 2072-2079.
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