Jiangsu Tetra New Material Technology Co., Ltd.
Jiangsu Tetra New Material Technology Co., Ltd.

Advantages and Characteristics of Cycloaliphatic Epoxy Applied to Electrical Casting Materials

Electrical casting materials refer to a type of epoxy insulation material used for casting insulators, transformers, or dry-type transformers. The formulation uses an anhydride-curing system with epoxy resin, primarily employing Bisphenol A epoxy resin, which offers advantages such as good processability, high cured material strength, good corrosion resistance, and excellent electrical properties. However, due to limitations in process conditions and the end-use environment of the products, issues such as high system viscosity, restricted powder addition ratios, and insufficient heat and weather resistance often arise. Cycloaliphatic epoxy, with their epoxy groups directly attached to aliphatic ring structures, can significantly increase the crosslinking density of the cured material, thereby providing higher heat resistance, weather resistance, and electrical insulation properties. Additionally, cycloaliphatic epoxide have extremely low viscosity and a significant dilution effect. Therefore, cycloaliphatic epoxy can compensate for the shortcomings of Bisphenol A epoxy resin in electrical casting material systems. When used together, they can improve the material's processability and enhance the safety of the final epoxy electrical insulation products.


Basic Information and Specifications of Cycloaliphatic Epoxy Resin TTA21


Basic Information


Chinese Name: 3,4-Epoxycyclohexylcarboxylic acid-3',4'-Epoxycyclohexyl methyl ester


English Name: 3,4-Epoxycyclohexylmethyl- 3',4'-Epoxycyclohexane Carboxylate


CAS No.: 2386-87-0


Structural Formula:

cycloaliphatic-epoxy-20240528-1.jpg

Molecular Weight: 252.31


Molecular Formula: C14H20O4


Specifications


Grade

TTA21S

TTA21L

TTA21P

Appearance

Colorless transparent liquid

Content

90% min

95% min

97% min

Epoxy Equivalent

(g/mol)

128-145

126-135

126-135

Color (APHA max)

100

50

50

Viscosity (cP)

180-450

220-300

220-300

Moisture

0.05% max

0.05% max

0.05% max

Acid Value

0.1% max

/

/

Total chlorine (ppm)//100max
Proportion1.1501.180


Basic Performance Data of Cycloaliphatic Epoxy Resin TTA21p Before and After Thermal Curing With Methyl Hexahydrophthalic Anhydride


Cycloaliphatic Epoxy

TTA21P

Parts

 100

Anhydride curing agent


MHHPA

Parts

130

Accelerator

AO-4

Parts

2

Viscosity

25℃

mPa·s

160

Thermal properties

Tg-DSC

226

△H

J/g

350

Peak temperature

195

Tg-TMA

225

α1

μm/m·℃

56

α2

μm/m·℃

174

Tg-DMA E'

189

208

tanδ

231

Mechanical property

Impact strength

KJ/

5.95

Flexural strength

MPa

125

Flexural modulus

MPa

3120

Tensile strength

MPa

57

Tensile modulus

MPa

3205

Elongation at break

%

2.8

Klc

Mpa*m1/2

0.45

Electrical properties

Volume resistivity

Ω*cm

1.168×1016

Surface resistivity

Ω

1.191×1015

Dielectric constant

C2/(N*M2)

3.0752

Dielectric loss

/

0.0042

Durometer

Shore D

/

89

Water absorption

25℃/24hr

%

1.05

Curing conditions

100℃x2hr+140℃×2hr+180℃×1hr


Effect of the Addition Ratio of Cycloaliphatic Epoxy Resin TTA21p on System Viscosity


cycloaliphatic-epoxy-20240528-2.jpg


Test material: TTA21P/128


Conclusion: With the increase of TTA21P addition ratio, the system viscosity decreases rapidly, and the dilution effect of TTA21P is very obvious.


Effect of the Addition Ratio of Cycloaliphatic Epoxy Resin TTA21P on Tg of Cured Products


cycloaliphatic-epoxy-20240528-3.jpg


Test materials and curing conditions: TTA21P/128/MHHPA/BDMA, 100℃×2h+140℃×2h+180℃×1h.


Conclusion: With the increase of TTA21P addition ratio, the Tg value of the cured product increased significantly, which shows that TTA21P can significantly improve the heat resistance of the material.


Effect of the Addition Ratio of Cycloaliphatic Epoxy Resin TTA21p on the Mechanical Properties of Materials


cycloaliphatic-epoxy-20240528-4.jpg


Test materials and curing conditions: TTA21P/128/MHHPA/BDMA, 100℃×2h+140℃×2h+180℃×1h.


Conclusion: As the addition ratio of this specialty resin chemical gradually increases in the range of 0%-30%, the impact strength and tensile strength of the material continue to increase, and the bending strength first increases and then decreases (reaching the maximum value at around 20%).


In summary, the best comprehensive performance can be achieved when the cycloaliphatic epoxy resin TTA21P by cycloaliphatic epoxy resin manufacturers is added in the system in a ratio of 10%-30%. The specific ratio is determined by the various indicators and requirements of the complete formula.

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