ThreeBond Technical News
Issued January 1, 2016

87

Trends in Automobile Body Stain-Proof Coatings
Introduction
Conventionally, we had been mainly been involved in development and release of automotive
aftermarket maintenance products, such as an anti-rust chassis coating as mandated at vehicle
inspection in Japan cleaner for brake maintenance, anti-rust lubricants for repair, inspection
and maintenance as well as other maintenance products. However, chassis coating is no longer
mandatory maintenance, and the automotive aftermarket has undergone fundamental changes
over the last decade. Currently, the driving force behind the industry is products such as bodycoatings and water repellents for window glasses. At ThreeBond, we have been working hard atdeveloping a variety interior, exterior and engine area products designed for cosmetic appeal andcomfort by harnessing our long history of resins, coatings and related technologies. Here, we will
introduce the types, features and performance of our body coatings, from their release in 2005
until their rise as trending products in the automotive aftermarket.

Table of Contents
Introduction.................................................1
1. Effects of Body Coating..........................2
2. Types of Body Coatings..........................2
2-1 Bases...............................................2
2-2 Water Affinity....................................2
3. Polysilazane............................................3

4. Ultra Glass Coating NEO........................4
5. Ultra Glass Coating NE’X........................6
6. Ultra Glass Coating Series
Characteristics Comparison ..................7
Closing........................................................81

1.

Effects of Body Coating

2.

Types of Body Coatings

Body coatings bring a variety of effects, such as gloss
retention and improvement, water repellency for coatedsurfaces, dirt repellency and improved efficacy of vehicle
cleaning maintenance. Regular cleaning and maintenancecan ensure long-term protection of the vehicle body.

2-1 Bases
Currently, a wide variety of body coatings are available,from the easy-to-apply general purpose monthly products
available at car parts dealers, to professional goods designed
for long-term durability that are pushed at dealerships. The
bases of these coatings vary as well, including wax, resin(polymer) and glass.
Wax Type
Though not currently enjoying widespread popularity, atypical wax is solid, mainly composed of natural carnauba,
and boasts deep luster and gloss. However, waxes are
difficult to apply and finish as they are applied with asponge, and all solids must be wiped away after drying.
Liquid waxes contain components such as carnauba resin,silicone oils or paraffin wax emulsions that are applied tostill-wet cars after cleaning, and some can simply be coatedon at the same time as a vehicle is wiped down. Liquid
wax is easy to install, glossy and water repellent, making
it excellent for general users so it is made available througha variety of products at major retailers. However, it has
low durability therefore effect last only one months or twomonths.
Resin TypeNew vehicle opptional services at dealers begin with resins.
These resins called paint sealant and are composed of paintsealants composed of fluorocarbon resin and silicone oil,using petroleum solvents as a medium. There are calledpolymer type also. Resins handled at dealers contain PTFE
(polytetrafluoroethylene), which is firmly sponge buffed
onto coated surfaces with an electric polisher. PTFE andresins are also used to fill scratches by forming a layer of oilthat provides gloss and water-repellency. This also includes
general market sponge coating applications of acrylic andsilicone resins.

2

Glass Type
Glass type is roughly divided into reactive and nonreactive
types. Reactive types contain moisture-curing oligomers
which are hydrolyzed by humidity in air to bind to coatedsurfaces and form a solid glass-based film (Fig. 1). Dealers
promoted manly reactive body coating. Non-reactive types
include simple water-soluble water-repellent coatings
containing silicone resin emulsions. These are called glassfiber types, and have very little durability because they aresimply painted on coated surfaces. Water soluble coatings
indicated as glass-based at major dealers are almost allclassified as these types. However, there are considerable
differences between reactive and inert (glass fiber) glass
types, but the reactive type demonstrates better durability
in its reaction with the vehicle body.

CH3 O

CH3
O
H2 O
Si O
CH3
CH3 O
Catalyst
O
CH3 n

CH3
O
Si O
OH

CH3 + CH3OH,n

CatalystO
Si O
O+ CH3OH, H2O

nFig. 1  Silane Oligomer Reaction

2-2 Water Affinity
Hydrophilic Types

Hydrophilic types do not repel water, but self-clean byforming a water film across the entire body to wash awayadhering dirt. However there are some issues. In case oflittle rain, there is not enough water to form the water film,
reducing this self-cleaning effect and dirt is difficult toremove once it adheres. These coatings do not give muchof a visual impression, so it became popular in the past but
then had been become to be avoided by general users.

Low Water-Repellent Types

Super Water-Repellent Types

The so called Ultra Glass Coating was the first active-type
coating introduced at ThreeBond. Using polysilazane as themain ingredient makes it a low water-repellent type that
reduces the likelihood of water spots and dirt adherence
to form an incredibly strong glass-based film. The watercontact angle of low water-repellent types is usually 70 to 80
degrees and these coatings are difficult to visually confirm,
so there has been a gradual shift toward water-repellent
types.

Our super water-repellent type is the ultimate coating—water droplets slide right off, and it boasts a contact angleof at least 150 degrees. However, the fine, uneven structure
formed on the surface is gradually broken down due tochafing which weakens its water repellency. As a result thistransparent and durable super water-repellent type has not
yet been put into practical use as a body coating. Currently,
it is used to coat sideview mirrors as they are affectedless by external factors. Even there, however, chafing andtouching causes irregularities in the coating to be broken
down, impairing the functionality of super water-repellent
coating.

Water-Repellent Types
Water droplets form into little balls and are repelled inwater-repellent types. They have gained popularity due to awater contact angle of over 90 degrees and visual presence
that is easy to confirm once applied. However, in some of
the conventional wax and resin water-repellent types aswell as glass types sold at dealerships, some water dropletsremain on the body. The magnifying effect when they dry
then creates difficult-to-remove water spots.
Water-Repellent and Hydrophobic Types
To solve the issues mentioned above, we developed a water
repellent and water slipable body coating. Improving thecoating film strength and adding water slip effect enabled awater contact angle of above 90 degrees and an even lower
angle of falling water. Water droplets roll right off, making
water spot formation unlikely. Furthermore, if a water spot
is caught early, it can be easily rinsed away, reducing theissues in repellent types. Our reactive polysilazane-based
Ultra Glass Coating NEO was released in 2009, and hassince been adopted by many automobile dealers.

Fig. 3  Super Water-Repellent Coating

3.

Polysilazane

Polysilazane coatings oxidize to form a strong glass
film (silica: SiO2). This polymerized compound contains
alternating silicon (Si) and nitrogen (N) which is hydrolyzed
by in the air then bond with hydroxyl groups on coatedsurfaces through covalent bonds. These coatings curequicker and have better adhesion than standard glass types.
H
Si N
H H n

H2O
Catalyst

O
Si O
O+ NH3 , H2nFig. 4  Polysilazane (Inorganic Polysilazane)
ReactionFig. 2  Water-Repellent and Hydrophobic Coating

Low Water-Repellent Type: Ultra Glass Coating
Due to water spots occurring in conventionally popularwater-repellent types, acid rain water droplets with nitrogenand sulfur oxides (NOX, SOX) from the atmosphere remainon the surface of the body. When the water evaporates due
to exposure to the sun, strongly acidic droplets are created
which corrode into the coating over time.

3

Water-Repellent Hydrophobic Single-Liquid HighDurability Type: Ultra Glass Coating NE’X)

We improved this issue in 2005, releasing our low waterrepellent Ultra Glass Coating, which forms a coating filmwith a water contact angle of 75 to 80 degrees to reduce
the aforementioned magnifying effect caused by water
droplets. While we were able to reduce water spot formationcompared to conventional types, the coating was still
difficult to visually confirm and dirt repellency decreased
during light rainfall.

At the end of 2015, we released Ultra Glass Coating NE’X,
a single-liquid version of Ultra Glass Coating NEO withimproved durability. Ultra Glass Coating NE’X is the latest
pinnacle of evolution in our body coating series. The hardfilm of a polysilazane base combined with our proprietary
technology to create a special water repellent that bonds tothree-dimensional structures to form a next-generation hardglass-based film with long-term durability.

Water-Repellent and Hydrophobic Type: Ultra Glass
Coating NEO

This pinnacle of body coatings has improved durability
for long-term maintenance of water repellency and gloss.
Furthermore, conversion to a single liquid shortens work
time to improve operations.

To deal with these issues, we began developing a bodycoating with a hard, hydrophobic film that repels water toreduce the development of water spots. In 2009, ThreeBondreleased our Ultra Glass Coating NEO products (ThreeBond6649 Coating / ThreeBond 6649B Finishing Agent) whichuses polysilazane as its main ingredient to create a durable
and strong glass film. Ultra Glass Coating NEO is a waterrepellent body coating agent which water rolls right off - nooff of, even when falling at small angles. We also improved
dirt repellency, and we are pleased that this coating has
become a mainstay in the automotive aftermarket.

4.

Ultra Glass Coating NEO(ThreeBond 6649/ThreeBond 6649B)

ThreeBond 6649 is the main agent in the series, with
polysilazane as the main ingredient for dirt repellency (Table1). ThreeBond 6649B is a finishing agent for removing
excess main agent and providing a uniform coating (Table2). By using the main agent, ThreeBond 6649, and thefinishing agent, ThreeBond 6649B form a hard, glass-based
film of SiO2 (Table 3).

Table 1  ThreeBond 6649 (Main Agent) Properties
Features

Unit

Measured Value

Testing Method

Remark(s)Appearance—

Colorless, transparent

3TS-2100-001—

Specific Gravity

—

0.80

3TS-2500-002

20°C

Non-Volatile Content%

5.5

3TS-2510-005

100°C × 5h

Table 2  ThreeBond 6649B (Finishing Agent) Properties
Features

Unit

Measured Value

Testing Method

Remark(s)Appearance

—

White

3TS-2100-001—

Specific gravity

—

0.95

3TS-2500-002

20°C

Non-Volatile Content%

3.4

3TS-2510-005

100°C × 5h

Table 3  Ultra Glass Coating NEO Coating Layer Characteristics

4

Features

Unit

Measured Value

Testing Method

Remark(s)Contact Angle (Water)°101

3TS-2A00-002

On a silicon wafer base

Pencil Scratch Hardness Test—

9H equivalent

3TS-2B00-009

SUS plate application

Adhesion Test (Cross-Cut Test)—

100/100

3TS-2140-001

SUS plate application

Table 4  Ultra Glass Coating NEO Accelerated Weather Resistance Test (Gloss)
ASTM G154
Accelerated Weather
Resistance Test

Initial Value

200 hrs.
= Approx. 1 yr.

400 hrs.
= Approx. 2 yr.

600 hrs.
= Approx. 3 yr.

800 hrs.
= Approx. 4 yr.

1000 hrs.
= Approx. 5 yr.

Gloss (°)

100

99

101

102

100

101

ASTM G154:

As defined by ASTM International industrial standards.
A coated plate is repeatedly exposed to ultraviolet rays, then misted with water and dried to reproduce a naturalenvironment.
Gloss is measured every hour.

Features

Table 6  Coefficient of Friction Test

2. Hydrophobic so that droplets more easily roll off thebody, making water spots less likely to form than withconventional water-repellent types.
3. This hydrophobic coating reduces the coefficient offriction so water slides off more readily, making it
harder for dirt to adhere. As a result dirt can be removed
through simple rinsing and water droplets are easier towipe away after rinsing for excellent maintainability(Table 6).
Ultra Glass Coating NEO maintains protection, even after
1,000 hours of the accelerated weather resistance test.
Furthermore there is less color difference after xenon arc
lamp accelerated weather resistance testing compared to an
un-coated piece for maintained protection (Table 5).

Coefficient of Friction Test

StaticDynamic
Coefficient of Coefficient ofFriction
Friction

Non-Treated

0.32

0.30

Ultra Glass Coating NEO

0.18

0.14

Reduction (%)

43.8

53.3

Test Area

1. Hard glass-based coating maintains long-term gloss(Table 4, 5).

Ultra Glass
Coating

Ultra Glass
Coating NEO

NonTreatedThis hydrophobic trait also reduces the friction coefficienton the body surface for improved resistance to scratches(Table 6).
We compared the degree of dirt adhesion using a whitebumper where it easily adheres (Fig. 5). Ultra Glass Coating
NEO prevented dirt from adhering far better than both the
non-treated surface and low water-repellent Ultra Glass
Coating.

Testing Method: White bumper was repeatedly dipped into
water containing a dirty substance, thenstaining degree was visually confirmed.

Fig. 5  Ultra Glass Coating NEO Dirt-Repellency

Table 5  Comparative Color Measurement(Xenon Arc Lamp, Accelerated Weather
Resistance Test)
ResultNon-TreatedUltra Glass
Coating NEO

After 33 days

0.46

0.17

After 78 days

0.50

0.17

Testing method: Coated plate left in a Ci4000 (ATLAS) tester for
33 and 78 days, then measured for differencein color (light source: D65, field of view: 10°,gauge: 5 mm).

Fig. 6  Ultra Glass Coating NEO Products

55.

Ultra Glass Coating NE’X
(ThreeBond 6659)

Features
1. The main ingredient, polysilazane, reacts with moisturein the air to form a hard glass-based film with an SiO2based framework.

ThreeBond 6659 is a single-liquid Ultra Glass Coating with
polysilazane as the main ingredient for stain-proof property(Table 7, 8). Ultra Glass Coating NE’X is part of the sameseries as NEO, but boasts improved concentration of its
glass base for even better durability. Additionally, water
repellency bonds at high density for long-term maintenanceof stain-proofing. While it is difficult to soil, it is also easy
to remove adhered dirt for excellent maintainability. Finally,making it a single liquid shortens work time and improves
productivity.

2. Ultra Glass Coating NE’X hard glass-based film boasts
excellent weather resistance.
3. Maintains long-term stain-proofing and gloss.
4. Single-liquid type for excellent workability.
The coating system of Ultra Glass Coating NE’X is part ofthe same series as NEO, but boasts improved concentrationof its glass base for even better protection. After 2,000
hours of the ASTM G 154 accelerated weather test, NE’X
maintained high gloss and excellent water repellency with alow contact angle (Fig. 4).

Table 7  ThreeBond 6659 Properties
Features

Unit

Measured Value

Testing Method

Remark(s)Appearance—

Colorless

3TS-2100-020—

Specific Gravity

—

0.74

3TS-2500-002

20°C

Non-Volatile Content%

6.2

3TS-2510-005

100°C × 5h

Table 8  Ultra Glass Coating NE’X Coating Layer Characteristics
Features

Unit

Measured Value

Testing Method

Remark(s)Contact Angle°

101

3TS-2A00-002

On a silicon wafer base

Pencil Scratch Hardness Test—

9H

3TS-2B00-008

SUS plate application

Cross-Cut Peel Test—

100/100

3TS-2140-001

SUS plate application

110

Gloss, Contact Angle (°)

100

90

80

NE’X Gloss

70

NE’X Contact Angle
NEO Gloss

60

50

NEO Contact Angle

Initial 100

200

300

400

500

600

700

800

2000h

900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000
Time (h)Fig. 7  Ultra Glass Coating NE’X and NEO Comparative Weather Resistance66.

Ultra Glass Coating Series Characteristics Comparison
Table 9  Ultra Glass Coating Series Characteristics Comparison
Gloss
5
4

Film Strength

Workability

321

Hydrophobicity

Maintainability

Durability

Stain-Proofing

Ultra Glass Coating NE’X
Gloss
5Glass Base: Water-Repellent Hydrophobic(Polysilazane)

Gloss
5

4

Workability

4Film Strength
3

3

2

2

1

1

Hydrophobicity

Maintainability

Durability

Film Strength

Workability

Stain-Proofing

Hydrophobicity

Maintainability

Durability

Stain-Proofing

Ultra Glass Coating NEO

Ultra Glass Coating

Glass Base: Water-Repellent Hydrophobic(Polysilazane)

Glass Base: Low Water Repellent(Polysilazane)

Fig. 8  Ultra Glass Coating NE’X Products

7

Closing

The Ultra Glass Coating Series’ products introduced here are designed to make your journey on the roadways as pleasant
as possible. In Japan, recent years have seen a continuing decline in automobile sales as the younger generation seeks otherforms of transportation , values change, society ages and the overall population declines. In response to this, dealerships arepromoting the sale of new vehicles by offering incidental service sets . In this competitive sales environment, we are developing
chemical products to meet market demand, leading to product development for incidental services and period inspection at
garages. As a part of our development, we will continue to work on the release of even more advanced body coatings.
<References>
1) ThreeBond Technical News 70: Vehicle Coating Agents, January 1, 2008
2) Ultra Glass Coating NEO, Catalog, AK2008005
3) Automotive Aftermarket: Exploring Market Vitalization from Body Coating Trends, April 2012

ThreeBond Fine Chemical Co., Ltd.  R&D Headquarters
Automotive Aftermarket Development Section, Development Division
Kazuhiro Kojima
Hiroyuki Onai

ThreeBond Co., Ltd.
8

4-3-3 Minamiosawa, Hachioji,
Tokyo 192-0398
Tel: +81-42-670-5333