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

Experimental Purpose and Conditions

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

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

Test Basis: Refer to QC/T 484-1999 Automotive Paint Coating Standard.

Experiment and Data Analysis

1. Black Paint Preparation:

Technical Parameters of Main Raw Materials:

Name	Aparência	Ponto de inflamação	Purity	Ponto de ebulição	Viscosity 25°C, mPa.s
EEP (3-Ethoxyethyl Propionate)	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

Black Paint Main Agent Formula (A1 & A2):

No.	Material	Amount A1	Amount A2	Supplier	Production Process
1	SM 516/70BAC Hydroxypropyl Resin	85.5	85.5	Cytec	Add ingredients in order, disperse at medium speed (500 rpm) for 5 minutes.
2	EEP	4.5	–	PREC
3	PMA	–	4.5	Commercial
4	9007-U Black Paste	10	10	Cody
	Total	100	100

Coating Curing Agent B Formula:

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

Thinner Formula (C1 & C2):

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

Coating Ratio:

• 2K PU Black (EEP) Ratio Main Agent A1 : Curing Agent B : Thinner C1 = 2 : 1 : 0.7
• 2K PU Black (PMA) Ratio Main Agent A2 : Curing Agent B : Thinner C2 = 2 : 1 : 0.7

2. Test Results and Analysis

Basic Performance:

No.	Test Items	Test Standards	Requirement	Test Results
				2K PU Black (EEP)	2K PU Black (PMA)
1	Liquid Coating Odor	–	As tested	Medium-low ether-ester odor	Medium ether-ester odor
2	Surface dry, h	GB/T 1728-1979	≤2	90 minutes	90 minutes
	Hard dry, h		≤24	12 h	12 h
3	Flowability 1	–	As tested	Left/Right: 2.70cm Up/Down: 3.00cm	Left/Right: 2.65cm Up/Down: 2.75cm
	Flowability 2	–	As tested	Left/Right: 2.40cm Up/Down: 3.15cm	Left/Right: 2.40cm Up/Down: 2.75cm
4	Film Appearance	–	Visual Inspection	Normal	Normal
5	Thickness (Flow Coating), μm	–	As tested	36.1	40.3
6	Gloss 20°/60°/85° angle	GB/T 9754-2007	As tested	89.0/93.7/100.0	88.1/93.7/99.8
7	Pencil Hardness (Scratch – Zhonghua)	GB/T 6739-2006	As tested	H	H
8	Cross-Cut Test, grade	GB/T 9286-1998	≤1	1	1
9	Impact Resistance, cm (Direct/Reverse)	GB/T 1732-1993	50/50	No crack/No crack	No crack/No crack
10	MEK Rub Resistance	–	100 cycles	No change	No change

Application Performance:

No.	Test Items	Test Standards	Requirement	Test Results
				2K PU Black (EEP)	2K PU Black (PMA)
1	Film Thickness, μm	Spray, stand 5 min, bake 80°C * 1 h	As tested	48.8	48.7
	Aparência		Visual	Smooth and even	Many tiny bubbles
Aparência
Appearance under magnification

Experimental Conclusion

1. The liquid coating of 2K PU Black (EEP) has a relatively lower odor; its flowability is slightly better; the flow-coated film thickness is lower, indicating better flowability; the gloss is slightly higher; the application performance is slightly better, allowing for a shorter standing time after spraying, resulting in a bubble-free film even at a higher thickness.
2. 2K PU Black (EEP) and 2K PU Black (PMA) are identical in terms of drying time, appearance, hardness, and adhesion.

The above tests prove that the new solvent EEP demonstrates potential for broad application in areas such as automotive refinish paints, vehicle coatings, marine paints, general industrial paints, wood coatings, floor paints, and anti-corrosion paints.

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