Comparative Application Testing of EEP and PMA in 2K PU System

Experimental Purpose and Conditions

Apply the new solvent EEP and the traditional solvent PMA respectively in a 2K PU system. Compare the performance differences generated by the two in the 2K PU system by analyzing the results of a series of tests.

Test Conditions: Temperature 25-27°C, Humidity 50-60%.

Test Basis: Refer to QC/T484-1999 Automotive Paint Coating Standard.

Experiment and Data Analysis

1. Clear Coat Preparation:

Technical Parameters of Main Raw Materials:

Name	Appearance	Flash Point	Purity	Boiling Point	Viscosity 25°C, mPa.s
EEP (Ethyl 3-Ethoxypropionate)	Colorless Transparent	59°C	≥99%	169°C	1.3
PMA (Propylene Glycol Monomethyl Ether Acetate)	Colorless Transparent	42°C	≥99%	145°C-146°C	1.6-2.5

Clear Coat Main Component Formulation:

No.	Material	Dosage A1	Dosage A2	Supplier	Production Process
1	SM 516/70BAC Hydroxypropyl Resin	95	95	Cytec	Add materials in sequence, disperse at medium speed 500 rpm for 5 minutes;
2	EEP	5	–	PREC
3	PMA	–	5	Commercial
	Total	100	100

Coating Curing Agent B Formulation:

No.	Material	Dosage	Supplier
1	HT-100 Curing Agent	30	Wanhua
2	Butyl Acetate	20	Commercial

Thinner Formulation:

No.	Material	Dosage C1	Dosage C2	Supplier
1	Butyl Acetate	90	90	Commercial
2	EEP	10	–	PREC
3	PMA	–	10	Commercial

Coating Ratio:

• 2K PU(EEP) Ratio: Main Agent A1 : Curing Agent B : Thinner C1 = 2 : 1 : 0.6
• 2K PU(PMA) Ratio: Main Agent A2 : Curing Agent B : Thinner C2 = 2 : 1 : 0.6

2. Test Results and Analysis

No.	Test Items	Test Standards	Requirement	Test Results
				2K PU(EEP)	2K PU(PMA)
1	Pot Life Viscosity (Clear Coat), S/T-2
	10 minutes	–	Measured	22.06	22.78
	2 hours	–	Measured	24.36	25.28
	4 hours	–	Measured	26.46	27.35
	6 hours	–	Measured	28.50	29.53
	Pot Life Adhesion, Grade (Polished Tinplate)
	10 minutes	–	≤1	1	1
	2 hours	–	≤1	1	1
	4 hours	–	≤1	1	1
	6 hours	–	≤1	1	1
2	Liquid Coating Odor	–	Measured	Mild ether-ester odor	Mild ether-ester odor
3	Clear Coat Viscosity, mPa.s@25.5°C	GB/T 2794-2013	Measured	1736.17	1861.53
4	Surface Dry, h	GB/T 1728-1979	≤2	90 minutes	90 minutes
	Hard Dry, h		≤24	12h	12h
5	Film Appearance	–	Visual Inspection	Normal	Normal
6	Thickness (Flow Coated), μm	–	Measured	35	38
7	Gloss 20°/60°/85° angle	GB/T 9754-2007	Measured	86.5/94.2/99.2	83.1/94.2/98.1
8	Pencil hardness (scratch – Zhonghua)	GB/T 6739-2006	Measured	H	H
9	Cross-cut test, grade	GB/T 9286-1998	≤1	1	1

Experimental Conclusion

Through the comparison of data from a series of tests, it is found that:

1. Compared to 2K PU(PMA), 2K PU(EEP) has slightly lower viscosity, slightly better flowability, slightly higher gloss, and slightly better application properties.
2. Compared with 2K PU(PMA), 2K PU(EEP) shows identical adhesion, hardness, and drying time.The above tests prove that the new solvent EEP may have important applications in fields such as automotive refinish paints, vehicle coatings, marine paints, general industrial paints, wood coatings, floor paints, and anticorrosive paints.

For further details on PREC’s functional solvents, please visit: PREC EEP Solvent