Process for forming coating film

A process for forming a coating film comprising coating, onto a substrate, a solvent type coating material prepared by blending a color pigment or combination of a metallic powder and a color pigment into base resin (A) containing a carboxylic acid amide copolymer as main component, then coating a transparent thermosetting powder coating material thereon, and thereafter heating and curing them.

This invention relates to a process for forming coating films applicable to 
uses requiring a high class of appearance such as overcoating material for 
automobile and the like. 
Since powder coating materials have various merits such that they are 
solventless which is desirable from the viewpoint of environmental 
protection, that a thick coating film having a thickness of 50.mu. or 
above can be produced therefrom by only one time of coating, that the 
powder coating material not adhered to substrate is easy to recover which 
yields only a small loss of coating material and is economical, and so on, 
the use of powder coating materials is rapidly expanding. However, when a 
powder coating material is used as an enamel and particularly as an 
overcoating metallic enamel for automobiles, namely when a metallic powder 
or combination of a metallic powder and a color pigment is mixed into a 
powder coating resin composition, it is yet quite difficult to obtain the 
same metallic feeling as in the hitherto known solvent type metallic 
coating materials by the electrostatic spray coating process due to the 
insufficient orientation of metallic powder in coating film caused by the 
difference in the quantity of electric charge between metallic powder and 
powder coating resin and the high melt viscosity of powder coating 
material, so that it is not yet practically employed. Apart from above, 
powder enamel has many problems also in point that the procedure of color 
changeover is quite complicated, including the case of using a powder 
enamel as a solid base. In order to solve these problems, 2-coat 1-bake 
finishing process is extensively studied at the present stage which 
comprises coating a usual thermosetting solvent type coating material 
(base coating material) containing a color pigment or combination of a 
color pigment and a metallic powder as enamel base, then overcoating a 
thermosetting transparent powder coating material (clear coating material) 
by the dry-on-wet method and finally heat-curing it. However, when a usual 
thermosetting solvent type coating material is used as a base coating 
material, various abnormalities of coating film, such as pin hole, surface 
roughening, metallic unevenness, etc., take place probably due to the 
residual solvent in coating film and the by-product of the thermosetting 
reaction, which are laborious to cope with. Particularly when these 
systems are applied to coating line of automobiles, there arises a problem 
in the coating workability at the time of repair. That is, if a defect is 
found out after coating a solvent type base coating material, overcoating 
a powder clear coating material thereon and baking it, the coating with 
the solvent type base coating material, the overcoating with the powder 
clear coating material and the baking have to be repeated again, which 
yields a very thick coating film and is apt to cause pin holes, surface 
roughening, etc. Therefore, a base coating material particularly excellent 
in workability and finish is necessary. 
Further, as a demand of market and in relation to the automobile coating 
line, the clear coating material to be coated over the solvent type base 
coating material is a usual solvent type clear coating material in some 
cases and a thermosetting powder clear coating material in some other 
cases. In the case of usual solvent type clear coating material, it must 
be baked at 140.degree.-150.degree. C. for about 20-30 minutes, while in 
the case of powder clear coating material a baking at 
160.degree.-170.degree. C. for about 20-30 minutes is necessary. 
Therefore, the base coating material put to this use is required to form a 
coating film of good performance, whether powder clear coating material or 
solvent type clear coating material is used. 
The present inventors conducted earnest studies with the aim of solving 
these problems and, as the result, achieved this invention. Thus, this 
invention provides a process for forming a coating film which comprises 
coating, onto a substrate, a solvent type coating material prepared by 
blending a color pigment or combination of a metallic powder and a color 
pigment into a base resin containing a carboxylic acid amide copolymer as 
main component, then overcoating a transparent thermosetting powder 
coating material thereon, and thereafter heating and curing them. 
By employing the process of this invention, the above-mentioned pin hole, 
surface roughening, etc. can be prevented and a coating film having good 
performances can be formed. 
The base resin A of this invention contains, as its main component, a 
carboxylic acid amide copolymer which will be detailed below. As the resin 
to be blended therewith, cellulose acetate butyrate resin, polyester 
resin, amino resin and the like are preferable. 
As the components for forming said carboxylic acid amide copolymer, 
.alpha.,.beta.-monoethylenic unsaturated carboxylic acid amides, 
N-alkoxyalkyl-substituted amides, .alpha.,.beta.-unsaturated carboxylic 
acids having one or more carboxyl groups, hydroxyalkyl 
.alpha.,.beta.-unsaturated carboxylates, unsaturated polyester resins, 
unsaturated monomers having glycidyl group, other copolymerizable 
unsaturated monomers and the like can be referred to. 
As said .alpha.,.beta.-monoethylenic unsaturated carboxylic acid amide, 
acrylamide or methacrylamide is preferably used. However, other 
copolymerizable unsaturated carboxylic acid amides can also be used, of 
which examples include itaconic acid diamide, .alpha.-ethylacrylamide, 
crotonic acid amide, fumaric acid diamide, maleic acid diamide and other 
.alpha.,.beta.-ethylenic unsaturated carboxylic acid amides having at most 
about 10 carbon atoms. Said unsaturated carboxylic acid amide is used in 
an amount of 2-20% by weight and preferably 5-15% by weight based on the 
carboxylic acid amide copolymer. If it is less than 2% by weight, the cure 
is insufficient and the cured product is unsatisfactory in solvent 
resistance. If it is larger than 20% by weight, blister easily takes place 
and coating film becomes insufficient in flexibility, which is 
undesirable. The carboxylic acid amide copolymer preferably used in this 
invention is a product obtained by modifying a carboxylic acid amide with 
an aldehyde and then etherifying it at least partially. The etherification 
is carried out by the use of an alcohol. 
In this carboxylic acid amide copolymer, it is necessary that one hydrogen 
atom of the amide group is substituted by a group represented by the 
following formula: 
##STR1## 
wherein R represents hydrogen atom when formaldehyde is used and 
represents alkyl group when other aliphatic aldehyde is used, and R.sub.1 
represents hydrogen atom or a residue obtained by subtracting hydroxyl 
group from the alcohol used for the etherification, i.e. an organic group 
such as alkyl group or aryl group. When the etherification is 
insufficient, problems are apt to arise in point of storage stability. As 
the alcohol used for the etherification, monohydric alcohols such as 
methanol, ethanol, propanol, pentanol and other alkanols having at most 
about 8 carbon atoms can be used, among which butanol and isobutanol are 
preferable. As alternative processes for producing the preferable 
carboxylic acid amide copolymer of this invention, a process which 
comprises carrying out the copolymerization by the use of an amide 
modified with an aldehyde such as alkylolamide in stead of said 
unsaturated carboxylic acid amide and then etherifying the copolymer or a 
process which comprises carrying out the copolymerization by the use of a 
N-alkoxyalkyl-substituted amide from the beginning can be referred to. 
Said N-alkoxyalkyl-substituted amide is represented by the following 
structural formula: 
##STR2## 
wherein R.sub.2 represents aliphatic hydrocarbon group having 2-6 carbon 
atoms and a single, polymerizable, .alpha.,.beta.-ethylenic, unsaturated, 
terminal group, and R.sub.3 represents lower alkyl group having 1-8 carbon 
atoms. The process for producing these substituted amides is mentioned in 
U.S. Pat. No. 3,079,434. Concrete examples of said 
N-alkoxyalkyl-substituted amide include N-methoxymethyl-(meth)acrylamide, 
N-ethoxyethyl-(meth)-acrylamide, N-butoxymethyl-(meth)acrylamide, 
N-isobutoxymethyl-(meth)acrylamide and the like. It is used in an amount 
of 4-40% by weight and preferably 10-30% by weight based on the carboxylic 
acid amide copolymer. 
As said .alpha.,.beta.-unsaturated carboxylic acid having one or more 
carboxyl group(s), acrylic acid, methacrylic acid, itaconic acid, maleic 
acid, fumaric acid, their monoalkyl esters, .alpha.-methyleneglutaric 
acid, aconitic acid, atropic acid, acid anhydride adducts of hydroxyalkyl 
esters of .alpha.,.beta.-unsaturated carboxylic acids and the like can be 
referred to. It is used in an amount of 0.5-10% by weight and preferably 
1-7% by weight. These acids not only play an important role as a catalyst 
for the crosslinking reaction of the carboxylic acid amide copolymer, but 
also the acid itself functions as a crosslinking group and exhibits a 
great effect upon the affinity and adhesion to pigment. However, when the 
amount of said .alpha.,.beta.-unsaturated carboxylic acid is less than 
0.5% by weight, the above-mentioned effects are insufficient. When the 
amount is larger than 10% by weight, the viscosity of the carboxylic acid 
amide copolymer obtained becomes high and its performances such as water 
resistance are deteriorated. 
As said hydroxyalkyl .alpha.,.beta.-unsaturated carboxylate, 2-hydroxyethyl 
acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 
4-hydroxybutyl acrylate, 5-hydroxyamyl acrylate, 6-hydroxyhexyl acrylate, 
7-hydroxyheptyl acrylate, 9-hydroxynonyl acrylate, 10-hydroxydecyl 
acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 
3-hydroxypropyl methacrylate, 6-hydroxyhexyl methacrylate, 8-hydroxyoctyl 
methacrylate, 10-hydroxydecyl methacrylate, 3-hydroxypropyl crotonate, 
5-hydroxyamyl crotonate, 6-hydroxyhexyl crotonate, 7-hydroxyheptyl 
crotonate, 10-hydroxydecyl crotonate, di(2-hydroxyethyl) maleate, 
di(4-hydroxybutyl) maleate, di(6-hydroxyhexyl) maleate, di(9-hydroxynonyl) 
maleate, di(10-hydroxydecyl) maleate, di(2-hydroxyethyl) fumarate, 
di(4-hydroxybutyl) fumarate, di(6-hydroxyhexyl) fumarate, 
di(10-hydroxydecyl) fumarate and the like can be referred to. Further, 
other substituents, including secondary hydroxyl group, halide group, 
nitrile group and analogous groups, may be introduced into the alkyl 
chain. Examples of such derivatives include 2,3-hydroxypropyl acrylate, 
3,5-dihydroxyamyl crotonate, 6,10-dihydroxydecyl methacrylate 
di(2-chloro-7-hydroxyheptyl) fumarate and the like. 
The hydroxyalkyl .alpha.,.beta.-unsaturated carboxylates are reactive with 
the carboxylic acid amide in the copolymer, and at the same time reactive 
with crosslinking agent such as melamine resin or the like if it is used. 
Therefore, it forms a good coating film at a lower temperature than in the 
case that said hydroxyalkyl .alpha.,.beta.-unsaturated carboxylate is not 
contained. The kind and amount of said crosslinking agent should be 
selected carefully with consideration of prevention of pin hole, surface 
roughening, etc. Said hydroxyalkyl .alpha.,.beta.-unsaturated carboxylate 
is used in an amount of 1-15% by weight and preferably 3-12% by weight. If 
it is less than 1% the curability at low temperature is deteriorated. If 
it is larger than 15%, curing progresses too speedily so that bad 
appearance such as pin hole can take place or it can remain unreacted to 
result in a drop in water resistance, which are both undesirable. 
Apart from above, the use of glycidyl group-containing unsaturated monomers 
such as glycidyl acrylate, glycidyl methacrylate, .beta.-methylglycidyl 
acrylate, .beta.-methylglycidyl methacrylate and the like is effective 
particularly when the adhesion between substrate and base coat is 
intensely desired, and its amount is preferably in the range of 0.5-5% by 
weight. If its amount is less than 0.5%, its use has no marked effect. If 
its amount exceeds 5%, the storage stability of the resin itself becomes 
worse, which is impractical. 
The unsaturated polyester resin used in this invention is obtained by 
reacting a known polyhydric alcohol with a known polybasic carboxylic acid 
by the known process at an elevated temperature. As said unsaturated 
polyester resin, those containing 0.5-5% by weight of an ethylenic 
unsaturated compound having carboxyl group, epoxy group, hydroxyl group or 
amide group in its starting composition are preferable for the reason that 
they should give a preferable carboxylic acid amide copolymer when 
copolymerized with the unsaturated monomer used in the carboxylic acid 
amide copolymer of this invention. Examples of the polyhydric alcohol 
usable include ethylene glycol, diethylene glycol, neopentyl glycol, 
1,6-hexanediol, 1,3-butylene glycol, 1,4-butylene glycol, 
bis(hydroxyethyl) terephthalate, hydrogenated Bisphenol A, 
trimethylolpropane, trimethylolethane, glycerin, pentaerythritol and the 
like. Examples of said polybasic carboxylic acid include phthalic acid 
(anhydride), isophthalic acid, terephthalic acid, trimellitic acid 
(anhydride), tetrahydrophthalic acid (anhydride), adipic acid, sebacic 
acid, azelaic acid, fumaric acid, maleic acid, benzoic acid, 
p-t-butylbenzoic acid, Versatic acid and the like. These unsaturated 
polyester resins are used for the purpose of improving the pigment 
dispersibility, pulverizability at the time of coating and low temperature 
curability of the solvent type coating material containing the carboxylic 
acid amide copolymer of this invention as a main component and forming a 
coating film having good finish appearance, and its molecular weight is 
preferably about 2,000-50,000 in terms of weight average molecular weight. 
It is used in an amount of 5-30% by weight, preferably. 
As said other copolymerizable unsaturated monomer used in this invention, 
(meth)acrylic esters having C.sub.1 -C.sub.18 alkyl group, vinyl-aromatic 
compounds such as styrene, .alpha.-methylstyrene, vinyltoluene and the 
like, organic nitriles such as acrylonitrile, methacrylonitrile and the 
like, vinyl esters of organic acids such as vinyl acetate, vinyl 
propionate and the like, esters of fumaric and maleic acids such as 
diethyl fumarate, dibutyl fumarate, diisopropyl maleate and the like, and 
esters of itaconic acid such as diethyl itaconate, dibutyl itaconate and 
the like can be referred to. Preferably, these unsaturated monomers are 
appropriately selected with consideration of the coating workability of 
the solvent type coating material containing carboxylic acid amide 
copolymer as a main component and the performances of the coating film. 
The carboxylic acid amide copolymer of this invention can be obtained by 
copolymerizing the monomers in an organic solvent in the presence of a 
vinyl polymerization initiator. This process is well known and its 
examples are shown in, for example, U.S. Pat. Nos. 2,978,437, 3,079,434, 
3,307,963 and 3,510,541. 
It is suitable for the purpose of this invention that the base resin A of 
this invention contains 1-20 parts by weight of cellulose acetate butyrate 
resin per 100 parts by weight of carboxylic acid amide copolymer as the 
main component. This is for the reason that cellulose acetate butyrate 
exhibits an excellent effect on the prevention of blister and, when a 
metallic powder is used, on the orientation of metallic powder. If its 
amount is less than 1 part by weight, the above-mentioned effect cannot be 
expected. If it is larger than 20 parts by weight, the cost rises and 
performances such as water resistance become unsatisfactory. As said 
cellulose acetate butyrate resin, those having various characteristic 
values can be used. Usually, however, those having a degree of butyration 
of 30% or more are preferable. As commercial products conforming to such a 
condition, "EAB-381", "EAB-551" and the like of Eastman Kodak Co. can be 
referred to, among which EAB-551-02 is particularly preferable. 
When base resin A of this invention is constituted of 30-94 parts by weight 
of carboxylic acid amide copolymer, 5-30 parts by weight of polyester 
resin, 1-20 parts by weight of cellulose acetate butyrate resin and 0-20 
parts by weight of amino resin, this solvent type coating material 
exhibits good performances for the above-mentioned object. Said polyester 
resin is used for the purpose of improving the pigment dispersibility, 
pulverizability at the time of coating, low temperature curability, etc. 
and for forming a coating film having a good finish appearance. It is used 
in an amount of 5-30 parts by weight per 100 parts by weight of the solid 
content in base resin A. As polyester resin used for these purposes, those 
having good miscibility with the carboxylic acid amide copolymer and 
having a molecular weight of about 2,000-50,000 in terms of weight average 
molecular weight are preferable. 
This polyester resin can be obtained by reacting a known polyhydric alcohol 
and a known polybasic carboxylic acid at an elevated temperature according 
to the well known process. Examples of the polyhydric alcohol usable 
include ethylene glycol, diethylene glycol, neopentyl glycol, 
1,6-hexanediol, 1,3-butylene glycol, 1,4-butylene glycol 
bis(hydroxyethyl)terephthalate, hydrogenated Bisphenol A, 
trimethylolpropane, trimethylolethane, glycerin, pentaerythritol and the 
like. Examples of the polybasic carboxylic acid include phthalic acid 
(anhydride), isophthalic acid, terephthalic acid, trimellitic acid 
(anhydride), tetrahydrophthalic acid (anhydride), hexahydrophthalic acid 
(anhydride), adipic acid, sebacic acid, azelaic acid, fumaric acid, maleic 
acid, benzoic acid, p-t-butylbenzoic acid, Versatic acid and the like. 
In base resin A, 1-20 parts by weight of cellulose acetate butyrate resin 
is used per 100 parts by weight of the solid content of base resin A. This 
is used for the same purpose as above, i.e. for preventing the pin hole 
and forming a coating film excellent in orientation of metallic powder 
when a metallic powder is used. If its amount is less than 1 part, its 
effect cannot be expected. If its amount is larger than 20 parts, the cost 
rises and performances such as water resistance become unsatisfactory. 
Though base resin A mainly comprising the carboxylic acid amide of this 
invention is self-crosslinkable originally, it may also be used in 
combination with an amino resin. In such a case, however, said amino resin 
is preferably selected with consideration of the prevention of pin hole 
and surface roughening. Concrete examples of said amino resin include 
methylated melamine resin, butylated melamine resin, isobutylated melamine 
resin and the like. These amino resins are used for the purpose of 
improving the low temperature curability, and their amount is preferably 
20 parts by weight or less per 100 parts by weight of the solid content in 
base resin A. 
By adding a color pigment or combination of a metallic powder and a color 
pigment to base resin A of this invention comprising the carboxylic acid 
amide copolymer, the polyester resin, the cellulose acetate butyrate 
resin, the amino resin, etc. to give a base coating material, and carrying 
out a 2-coat 1-bake finishing which comprises coating the base coating 
material onto a primer formed by electrodeposition coating on a substrate, 
further coating a transparent thermosetting powder coating material 
thereon and baking them at 160.degree.-170.degree. C. for 20-30 minutes, a 
coating film free from defects such as pin hole, surface roughening, etc., 
having an excellent appearance and having a good adhesion to substrate can 
be formed. 
A coating film good in both appearance and coating film performances can 
also be obtained by coating the substrate with a usual solvent type of 
acryl-melamine crosslinkable clear coating material in stead of the 
above-mentioned transparent thermosetting powder coating material and 
baking it at 140.degree.-150.degree. C. for 20-30 minutes. 
As the transparent thermosetting powder coating material used as the clear 
coating material for 2-coat 1-bake finish, various types of powder coating 
materials extensively in use can be employed. For the overcoating of 
automobiles which is the main object of this invention, acrylic powder 
coating materials prepared by blending an acrylic copolymer resin 
comprising a vinyl monomer having glycidyl or hydroxyl group such as 
glycidyl methacrylate, glycidyl acrylate, hydroxyethyl acrylate or 
hydroxyethyl methacrylate as a functional monomer and alkyl acrylate, 
alkyl methacrylate, styrene or the like as a non-functional monomer with 
appropriate quantities of polybasic carboxylic acid, block isocyanate or 
the like as a curing agent component and further with appropriate 
quantities of coating surface regulator, anticissing agent and the like 
are particularly preferable, although polyester type coating materials can 
also be used. 
In the following preparative examples and examples, "parts" means "parts by 
weight".

Preparative Example 1 
Preparation of Carboxylic Acid Amide Copolymer 1 
25 Parts of n-butanol, 75 parts of xylene, 10 parts of acrylamide, 40 parts 
of methyl methacrylate, 2.5 parts of methacrylic acid, 47.5 parts of ethyl 
acrylate, 1.5 parts of t-dodecylmercaptan and 1 part of cumene 
hydroperoxide were charged into a reaction vessel equipped with a stirrer, 
a thermometer, a cooler and a decanter. The mixture was heated to 
100.degree. C. in one hour and kept at 100.degree. C. for 8 hours. While 
it was kept at this temperature, each 0.5 part of cumene hydroperoxide as 
a polymerization initiator was added three times at intervals of 2 hours. 
Then, 20 parts of 40% solution of formaldehyde in n-butanol and 0.4 part of 
maleic anhydride were added, and the mixture was heated under reflux for 4 
hours while removing water from the decanter. The carboxylic acid amide 
copolymer 1 thus obtained was a transparent and viscous liquid having a 
solid content of 50.5% and an acid number of 7.5. 
Preparative Example 2 
Preparation of Carboxylic Acid Amide Copolymer 2 
25 Parts of n-butanol and 75 parts of xylene were charged into a reaction 
vessel equipped with a stirrer, a thermometer and a cooler, and heated to 
100.degree. C. Then, a mixture comprising 20 parts of 
N-butoxymethylacrylamide, 2 parts of acrylic acid, 30 parts of methyl 
methacrylate, 38 parts of ethyl acrylate, 10 parts of n-butyl acrylate and 
1 part of benzoyl peroxide was added into this reaction vessel over a time 
period of 4 hours. After addition, each 0.2 part of benzoyl peroxide was 
three times added at intervals of one hour, and then the mixture was kept 
at 100.degree. C. for 5 hours. The carboxylic acid amide copolymer 2 thus 
obtained was a transparent and viscous liquid having a solid content of 
50.3% and an acid number of 8.5. 
Preparative Example 3 
Preparation of Carboxylic Acid Amide Copolymer 3 
25 Parts of n-butanol, 75 parts of xylene, 10 parts of acrylamide, 5 parts 
of 2-hydroxyethyl methacrylate, 2 parts of glycidyl methacrylate, 33 parts 
of methyl methacrylate, 25 parts of methacrylic acid, 47.5 parts of ethyl 
acrylate, 1.5 parts of t-dodecylmercaptan, and 1 part of cumene 
hydroperoxide were charged into a reaction vessel equipped with a stirrer, 
a thermometer, a cooler and a decanter. The temperature of the mixture was 
elevated to 100.degree. C. in one hour, and it was kept at this 
temperature for 8 hours, during which each 0.5 part of cumene 
hydroperoxide as a polymerization initiator was added three times at 
intervals of 2 hours. 
Then, 20 parts of 40% solution of formaldehyde in n-butanol and 0.4 part of 
maleic anhydride were added, and the resulting mixture was heated under 
reflux for 4 hours while removing water from the decanter. The carboxylic 
acid amide copolymer 3 thus obtained was a transparent viscous liquid 
having a solid content of 50.5% and an acid number of 7.5. 
Preparative Example 4 
Preparation of Carboxylic Acid Amide Copolymer 4 
25 Parts of n-butanol and 75 parts of xylene were charged into a reaction 
vessel equipped with a stirrer, a thermometer and a cooler, and the 
temperature of the mixture was elevated to 100.degree. C. 
Then, a mixture comprising 20 parts of N-methoxymethylmethacrylamide, 2 
parts of acrylic acid, 5 parts of 2-hydroxyethyl methacrylate, 2 parts of 
glycidyl methacrylate, 23 parts of methyl methacrylate, 38 parts of ethyl 
acrylate, 10 parts of n-butyl acrylate and 1 part of benzoyl peroxide was 
added over a time period of 4 hours. After the addition, each 0.2 part of 
benzoyl peroxide was 3 times added at intervals of 1 hour, and the 
resulting mixture was kept at 100.degree. C. for 5 hours. The carboxylic 
acid amide copolymer 4 thus obtained was a transparent viscous liquid 
having a solid content of 50.3% and an acid number of 8.5. 
Preparative Example 5 
Preparation of Unsaturated Polyester Resin A 
1,080 Parts of isophthalic acid, 467 parts of adipic acid, 29 parts of 
maleic anhydride, 53.6 parts of trimethylolpropane, 832 parts of neopentyl 
glycol and 0.3 part of hydroquinone were charged into a reaction vessel 
equipped with a stirrer, a thermometer and a nitrogen gas inlet tube, and 
reacted at 220.degree. C. while blowing nitrogen thereinto until the acid 
number reached 9. After cooling the reaction vessel, the mixture was 
diluted with a solvent mixture comprising n-butanol, butyl acetate and 
xylene (20/10/70, ratio by weight) so that the concentration of the solid 
component became 50%. The unsaturated polyester resin A thus obtained was 
a transparent viscous liquid having an acid number of 4.5. 
Preparative Example 6 
Preparation of Unsaturated Polyester Resin B 
1,112 Parts of isophthalic acid, 482 parts of adipic acid, 26 parts of 
itaconic acid, 728 parts of neopentyl glycol, 90 parts of 1,4-butanediol, 
536 parts of trimethylolpropane and 0.6 part of hydroquinone were charged 
into the same reaction vessel as above, and reacted while blowing nitrogen 
until the acid number of the mixture reached 10. After cooling the 
reaction vessel, the mixture was diluted with a solvent mixture comprising 
n-butanol, butyl acetate and xylene (20/10/70, ratio by weight) so that 
the concentration of solid component became 50%. The polyester resin B 
thus obtained was a transparent viscous liquid having an acid number of 5. 
Preparative Example 7 
Preparation of Carboxylic Acid Amide Copolymer 5 
25 Parts of n-butanol, 65 parts of xylene, 10 parts of acrylamide, 30 parts 
of methyl methacrylate, 20 parts of unsaturated polyester resin A, 2.5 
parts of methacrylic acid, 47.5 parts of ethyl acrylate, 1.5 parts of 
t-dodecylmercaptan and 1 part of cumene hydroperoxide were charged into a 
reaction vessel equipped with a stirrer, a thermometer, a cooler and a 
decanter. After elevating the temperature of the mixture to 100.degree. C. 
in one hour, the mixture was kept at 100.degree. C. for 8 hours. 
Then, 20 parts of 40% solution of formaldehyde in n-butanol and 0.4 part of 
maleic anhydride were added, and the resulting mixture was heated under 
reflux for 4 hours while removing water from the decanter. The carboxylic 
acid amide copolymer 5 thus obtained was a transparent viscous liquid 
having a solid content of 50.5% and an acid number of 7.7. 
Preparative Example 8 
Preparation of Carboxylic Acid Amide Copolymer 6 
25 Parts of n-butanol and 60 parts of xylene were charged into a reaction 
vessel equipped with a stirrer, a thermometer, a dropping funnel and a 
cooler, and the temperature of the mixture was elevated to 100.degree. C. 
Then, a mixture comprising 20 parts of N-butoxymethylacrylamide, 2 parts 
of acrylic acid, 20 parts of methyl methacrylate, 30 parts of unsaturated 
polyester resin B, 38 parts of ethyl acrylate, 10 parts of n-butyl 
acrylate and 1 part of benzoyl peroxide was added into the reaction vessel 
over a time period of 4 hours. After addition, each 0.2 part of benzoyl 
peroxide was three times added at intervals of 1 hour, and the mixture was 
kept at 100.degree. C. for 5 hours. The carboxylic acid amide copolymer 6 
thus obtained was a transparent viscous liquid having a solid content of 
50.7% and an acid number of 8.8. 
Preparative Example 9 
Preparation of Polyester Resin A 
1,080 Parts of isophthalic acid, 511 parts of adipic acid, 832 parts of 
neopentyl glycol and 536 parts of trimethylolpropane were charged into a 
reaction vessel equipped with a stirrer, a thermometer and a nitrogen gas 
inlet tube, and reacted at 220.degree. C. while flowing nitrogen until the 
acid number of the mixture reached 8. After cooling the reaction vessel, 
the mixture was diluted with a solvent mixture comprising n-butanol, butyl 
acetate and xylene (20/10/70, ratio by weight) so that the concentration 
of the solid component became 50%. The polyester resin A thus obtained was 
a transparent liquid having an acid number of 4.0. 
Preparative Example 10 
Preparation of Polyester Resin B 
1,112 Parts of isophthalic acid, 482 parts of adipic acid, 728 parts of 
neopentyl glycol, 90 parts of 1,4-butanediol and 536 parts of 
trimethylolpropane were charged into the same reaction vessel as above, 
and reacted at 220.degree. C. while blowing nitrogen until acid number of 
the mixture reached 9. After cooling the reaction vessel, the mixture was 
diluted with a solvent mixture comprising n-butanol, butyl acetate and 
xylene (20/10/70, ratio by weight) so that the concentration of the solid 
component became 50%. The polyester resin B thus obtained was a 
transparent liquid having an acid number of 4.5. 
Preparative Example 11 
Preparation of Thermosetting Acrylic Powder Coating Material A 
A monomer mixture comprising 20 parts of methyl methacrylate, 20 parts of 
n-butyl methacrylate, 30 parts of styrene, 5 parts of n-butyl acrylate, 5 
parts of hydroxyethyl acrylate and 20 parts of glycidyl methacrylate was 
copolymerized to obtain a solid copolymer resin having a weight average 
molecular weight of 10,000. Its 90 parts was melt-blended with 10 parts of 
sebacic acid by means of an extruder, after which the mixture was cooled 
and pulverized. The powdery particles passing 200 mesh sieve were 
collected to obtain acrylic powder coating material A. 
Preparative Example 12 
Preparation of Thermosetting Acrylic Powder Coating Material B 
A monomer mixture comprising 30 parts of styrene, 20 parts of methyl 
methacrylate, 10 parts of ethyl acrylate, 20 parts of n-butyl acrylate and 
25 parts of hydroxyethyl methacrylate was copolymerized to obtain a solid 
copolymer resin having a weight average molecular weight of 12,000. Its 65 
parts was melt-blended with 35 parts of Adduct B-1870 (block isocyanate 
type of curing agent) and 1 part of Modaflow (manufactured by Monsanto 
Co.) by means of an extruder, and then the mixture was cooled and 
pulverized. The powdery particles passing 200 mesh sieve were collected to 
obtain acrylic powder coating material B. 
Preparative Example 13 
Preparation of Acrylic Copolymer A 
Into a reactor equipped with a stirrer, a thermometer and a condenser were 
charged 20 parts of n-butanol and 80 parts of xylene, and the temperature 
of the contents was elevated to 100.degree. C. To the reactor was 
thereafter added a mixture consisting of 8 parts of 2-hydroxyethyl 
methacrylate, 2 parts of methacrylic acid, 45 parts of methyl 
methacrylate, 45 parts of ethyl acrylate, and 1 part of benzoyl peroxide 
over 4 hours. After the completion of the addition, 0.2 part-portions of 
benzoyl peroxide were added three times every one hour, and the resulting 
mixture was then kept at 100.degree. C. for 5 hours. The acrylic copolymer 
A thus obtained was a transparent, viscous liquid, and had a solid content 
of 50.1% and an acid value of 6.5. 
EXAMPLE 1 
Using carboxylic acid amide copolymer 1, a base coating material having the 
following formulation was prepared: 
______________________________________ 
Carboxylic acid amide copolymer 1 
54 parts 
15% Solution of EAB-551-02* in 
Cellosolve acetate 20 parts 
Alpaste #1109 MA** 8 parts 
Colofine blue #720*** 2 parts 
______________________________________ 
*Cellulose acetate butyrate resin manufactured by Eastman Kodak Co. 
**Aluminum paste manufactured by Toyo Aluminium K.K. 
***Organic pigment manufactured by Dainippon Ink Kagaku K.K. 
The above-mentioned coating material was diluted with a solvent mixture 
comprising toluene, butyl acetate and Solvesso #150 (50/40/10, ratio by 
weight) and adjusted to 13 seconds as measured with Fc #4 (25.degree. C.). 
This base coating material was applied to a surface-treated steel board 
(JIS G-3310 steel board chemically treated with zinc phosphate system) 
coated with an automobile cationic electrodeposition coating primer so as 
to give a dry coating thickness of 20.mu., after which it was set for 5 
minutes. Then, thermosetting acrylic powder coating material A was coated 
on the wet coating film so as to give a film thickness of 80.mu. and baked 
at 170.degree. C. for 30 minutes. The coating film thus obtained was quite 
excellent in the finished appearance, good in coating film performances 
such as solvent resistance, water resistance, weather resistance, etc. as 
indicated in Table 1, and useful as an overcoating film for automobiles. 
EXAMPLE 2 
Using carboxylic acid amide copolymer 2, a base coating material having the 
following formulation was prepared: 
______________________________________ 
Carboxylic acid amide copolymer 2 
54 parts 
15% Solution of EAB-551-02 in 
Cellosolve acetate 20 parts 
Alpaste #1109 MA 8 parts 
Colofine blue #720 2 parts 
______________________________________ 
The above-mentioned coating material was diluted with a solvent mixture 
comprising toluene, butyl acetate and Solvesso #150 (50/40/10, ratio by 
weight) and adjusted to 13 seconds as measured with Fc #4 (25.degree. C.). 
The base coating material thus obtained was applied to a surface-treated 
steel board (JIS G-3310 steel board chemically treated with zinc phosphate 
system) coated with an automobile cationic electrodeposition coating 
primer so as to give a dry film thickness of 20.mu. and then set for 5 
minutes. Then, thermosetting acrylic powder coating material A was coated 
onto the wet coating film so as to give a film thickness of 80.mu. and 
baked at 170.degree. C. for 30 minutes. The coating film thus obtained was 
excellent in finished appearance, good in coating film performances such 
as solvent resistance, water resistance, weather resistance, etc. as 
indicated in Table 1, and useful as an overcoating film for automobiles. 
EXAMPLE 3 
Using carboxylic acid amide copolymer 3, a base coating material having the 
following formulation was prepared: 
______________________________________ 
Carboxylic acid amide copolymer 3 
54 parts 
15% Solution of EAB-551-02 in 
Cellosolve acetate 20 parts 
Alpaste #1109 MA 8 parts 
Colofine blue #720 2 parts 
______________________________________ 
The above-mentioned coating material was diluted with a solvent mixture 
comprising toluene, butyl acetate and Solvesso #150 (50/40/10, ratio by 
weight) and adjusted to 13 seconds as measured with Fc #4 (25.degree. C.). 
The base coating material thus obtained was applied to a surface-treated 
steel board (JIS G-3310 steel board chemically treated with zinc phosphate 
system) coated with an automobile cationic electrodeposition coating 
primer so as to give a dry film thickness of 20.mu. and then set for 5 
minutes. Subsequently, thermosetting acrylic powder coating material A was 
coated onto the wet coating film so as to give a film thickness of 80.mu. 
and baked at 170.degree. C. for 30 minutes. The coating film thus obtained 
was excellent in finished appearance and adhesion to the electrodeposition 
coated steel board, good in coating film performances such as solvent 
resistance, water resistance, weather resistance, etc. as indicated in 
Table 1, and useful as an overcoating for automobiles. 
Further, in order to evaluate the coating film performances given by low 
temperature baking, the thermosetting acrylic powder coating material A as 
the clear coating material was replaced with a clear coating material 
obtained by blending Dianal HR-538 (usual acryl-melamine crosslinkable 
solvent type resin manufactured by Mitsubishi Rayon K.K., solid content 
50%) with Uban 20 SE (melamine resin manufactured by Mitsui-Toatsu Kagaku 
K.K., solid content 60%) at an acryl (solid)/melamine (solid) ratio of 
70/30 and diluting the blended mixture with Supersol #1500 (manufactured 
by Mitsubishi Sekiyu K.K.) as a thinner so as to give the appointed 
viscosity. Thus, after applying the base coating material of this 
invention and setting it for 3 minutes, said clear coating material was 
coated thereon by wet-on-wet method so as to give a dry film thickness of 
3.mu. and baked at 140.degree. C. for 30 minutes. The coating film thus 
obtained had good finished appearance, solvent resistance and weather 
resistance and was useful as an overcoating film for automobiles. 
EXAMPLE 4 
Using carboxylic acid amide copolymer 4, a base coating material having the 
following formulation was prepared: 
______________________________________ 
Carboxylic acid amide copolymer 4 
54 parts 
Sumimal M-504C* 2 parts 
15% Solution of EAB-551-02 in 
Cellosolve acetate 20 parts 
Alpaste #1109 MA 8 parts 
Colofine blue #720 2 parts 
______________________________________ 
*Methylated melamine resin manufactured by Sumitomo Kagaku K.K. (68% 
solution) 
The above-mentioned coating material was diluted with a solvent mixture 
comprising toluene, butyl acetate and Solvesso #150 (50/40/10, ratio by 
weight) and adjusted to 13 seconds as measured with Fc #4 (25.degree. C.). 
The base coating material thus obtained was applied to a surface-treated 
steel board (JIS G-3310 steel board chemically treated with zinc phosphate 
system) coated with an automobile cationic electrodeposition coating 
primer so as to give a dry film thickness of 20.mu. and set for 5 minutes, 
after which thermosetting acrylic powder coating material A was coated on 
the wet coating film so as to give a film thickness of 80.mu. and baked at 
170.degree. C. for 30 minutes. The coating film thus obtained was 
excellent in finished appearance and adhesion to the electrodeposition 
coated board, good in coating film performances such as solvent 
resistance, water resistance, weather resistance, etc. as indicated in 
Table 1, and useful as an overcoating film for automobiles. 
In order to evaluate its coating film performances given by low temperature 
baking, the thermosetting acrylic powder coating material A was replaced 
with a clear coating material obtained by blending Dianal HR-538 with Uban 
20 SE at an acryl (solid)/melamine (solid) ratio of 70/30 and diluting the 
blended mixture with Supersol #1500 as a thinner so as to give the 
appointed viscosity. Thus, after applying the base coating material of 
this invention and setting it for 3 minutes, said clear coating material 
was coated thereon by wet-on-wet method so as to give a dry film thickness 
of 30.mu. and baked at 140.degree. C. for 30 minutes. The coating film 
thus obtained had good finished appearance, solvent resistance and weather 
resistance and was useful as an overcoating film for automobiles. 
EXAMPLE 5 
Using carboxylic acid amide copolymer 5, a base coating material having the 
following formulation was prepared: 
______________________________________ 
Carboxylic acid amide copolymer 5 
54 parts 
15% Solution of EAB-551-02 in 
Cellosolve acetate 20 parts 
Alpaste #1109 MA 8 parts 
Colofine blue #720 2 parts 
______________________________________ 
The above-mentioned coating material was diluted with a solvent mixture of 
toluene, butyl acetate and Solvesso #150 (50/40/10, ratio by weight) and 
adjusted to 13 seconds as measured with Fc #4 (25.degree. C.). The 
above-mentioned base coating material A was applied to a surface-treated 
steel board (JIS G-3310 steel board chemically treated with zinc phosphate 
system) coated with an automobile cationic electrodeposition coating 
primer so as to give a dry film thickness of 20.mu. and set for 5 minutes, 
after which thermosetting acrylic powder coating material A was coated on 
the wet coating film so as to give a dry film thickness of 80.mu. and 
baked at 170.degree. C. for 30 minutes. The coating film thus obtained was 
excellent in finished appearance, good in coating film performances such 
as solvent resistance, water resistance, weather resistance, etc. as 
indicated in Table 1, and useful as an overcoating film for automobiles. 
In order to evaluate its coating film performances given by low temperature 
baking, the thermosetting acrylic powder coating material A was replaced 
with a clear coating material obtained by blending Dianal HR-538 with Uban 
20 SE at an acryl (solid)/melamine (solid) ratio of 70/30 and diluting the 
blended mixture with Supersol #1500 as a thinner so as to give a viscosity 
of 30 seconds as measured with Fc #4 (25.degree. C.). Thus, after applying 
the base coating material of this invention so as to give a dry film 
thickness of 20.mu. and setting it for 3 minutes, said clear coating 
material was coated thereon by wet-on-wet method so as to give a dry film 
thickness of 30.mu. and baked at 140.degree. C. for 30 minutes. The 
coating film thus obtained had good finished appearance, solvent 
resistance and weather resistance and was useful as an overcoating film 
for automobiles. 
EXAMPLE 6 
Using carboxylic acid amide copolymer 6, a base coating material having the 
following formulation was prepared: 
______________________________________ 
Carboxylic acid amide copolymer 6 
57 parts 
15% Solution of EAB-551-02 in 
Cellosolve acetate 10 parts 
Alpaste #1109 MA 10 parts 
______________________________________ 
An overcoating film for automobiles was prepared by repeating the procedure 
of Example 5, except that the base coating material used in Example 5 was 
replaced with the above-mentioned base coating material. The coating film 
thus obtained was free from defects in coating film such as pin hole, 
yellowing, marked orange peel and the like and good in metallic feeling 
and sharpness. The coating film was also good in coating film 
performances, such as solvent resistance, water resistance, weather 
resistance, etc. as indicated in Table 1. 
Further, in order to evaluate the performances in case of repair, the 
above-mentioned 2-coat 1-bake board was partially overcoated again with 
the base coating material of this invention and the thermosetting acrylic 
powder coating material A and baked at 170.degree. C. for 30 minutes. As 
the result, there was formed a coating film in which the part again coated 
and baked was not greatly different in finished appearance from the other 
part. The adhesion between these coating films were also good. 
EXAMPLE 7 
Using carboxylic acid amide copolymer 1, a base coating material having the 
following formulation was prepared: 
______________________________________ 
Carboxylic acid amide copolymer 1 
48 parts 
Polyester resin A 6 parts 
15% Solution of EAB-551-02 in 
Cellosolve acetate 20 parts 
Alpaste #1109 MA 8 parts 
Colofine blue #720 2 parts 
______________________________________ 
The above-mentioned coating material was diluted with a solvent mixture 
comprising toluene, butyl acetate and Solvesso #150 (50/40/10, ratio by 
weight) and adjusted to 13 seconds as measured with Fc #4 (25.degree. C.). 
The base coating material thus obtained was applied to a surface-treated 
steel board (JIS G-3310 steel board chemically treated with zinc phosphate 
system) coated with an automobile cationic electrodeposition coating 
primer so as to give a dry film thickness of 20.mu. and set for 5 minutes. 
Then, thermosetting acrylic powder coating material A was coated on the 
wet coating film so as to give a film thickness of 80.mu. and baked at 
170.degree. C. for 30 minutes. The coating film thus obtained was 
excellent in finished appearance, good in coating film performances such 
as solvent resistance, water resistance, weather resistance, etc. as 
indicated in Table 1, and useful as an overcoating film for automobiles. 
Further, in order to evaluate the performances in case of repair, the 
above-mentioned 2-coat 1-bake board was partially coated again with the 
base coating material and thermosetting acrylic powder coating material A 
and baked at 170.degree. C. for 30 minutes. 
As a result, the part again coated and baked was not greatly different from 
the other part in finished appearance, and there was formed a coating film 
having a good finished appearance. The adhesion between these coating 
films was also good. 
EXAMPLE 8 
Using carboxylic acid amide copolymer 4 and polyester resin B, a base 
coating material having the following formulation was prepared: 
______________________________________ 
Carboxylic acid amide copolymer 4 
48 parts 
Polyester resin B 9 parts 
Sumimal M-504C 2 parts 
15% Solution of EAB-551-02 in 
Cellosolve acetate 10 parts 
Alpaste #1109 MA 10 parts 
______________________________________ 
The above-mentioned base coating material was diluted in the same manner as 
in Example 7, applied to the same surface-treated steel board coated with 
an electrodeposition coating primer as used in Example 7 according to the 
coating process of Example 1 so as to give a dry film thickness of 20.mu. 
and set for 5 minutes. Then, thermosetting acrylic powder coating material 
A was coated thereon so as to give a dry film thickness of 80.mu. and 
baked at 170.degree. C. for 30 minutes. The coating film thus obtained was 
free from defects in coating film such as pin hole, yellowing, marked 
orange peel, etc. and good in metallic feeling and sharpness. The coating 
film was also good in coating film performances, such as solvent 
resistance, water resistance, weather resistance, etc. as indicated in 
Table 1. 
Further, in order to evaluate its performances in case of low temperature 
baking, the thermosetting acrylic powder coating material A as a clear 
coating material was replaced with a clear coating material obtained by 
blending Dianal HR-538 with Uban 20 SE at an acryl (solid)/melamine 
(solid) ratio of 70/30 and diluting the blended mixture with Supersol 
#1500 so as to give an appointed viscosity. Thus, after applying the base 
coating material of this invention and setting it for 3 minutes, said 
clear coating material was coated by wet-on-wet method so as to give a dry 
film thickness of 30.mu. and baked at 140.degree. C. for 30 minutes. The 
coating film thus obtained had good finished appearance, solvent 
resistance and weather resistance and was useful as an overcoating film 
for automobiles. 
EXAMPLE 9 
A coating film similar to that of Example 8 was prepared by using 
thermosetting acrylic powder coating material B in place of the 
thermosetting acrylic powder coating material A of Example 8. 
The coating film thus obtained was good in finished appearance and other 
coating film performances, similarly to that of Example 8, as indicated in 
Table 1. 
EXAMPLE 10 
Using carboxylic acid amide copolymer 2 and polyester resin A, a base 
coating material having the following formulation was prepared: 
______________________________________ 
Carboxylic acid amide copolymer 2 
42 parts 
Polyester resin A 12 parts 
15% Solution of EAB-551-02 in 
Cellosolve acetate 5 parts 
Sumimal M-504C 1.1 parts 
Titanium oxide R-820* 2 parts 
Irgazin yellow 2GLT** 4 parts 
______________________________________ 
*Pigment manufactured by Ishihara Sangyo K.K. 
**Pigment manufactured by Ciba Geigy Co. 
The above-mentioned coating material was diluted with a solvent mixture 
comprising Cellosolve acetate and toluene (20/80, ratio by weight) to 18 
seconds as measured with Fe #4 (25.degree. C.). 
The base coating material thus obtained was applied to the same 
surface-treated steel board coated with an electrodeposition coating 
primer as used in Example 1 so as to give a dry film thickness of 20.mu. 
and set for 5 minutes. Then, thermosetting acrylic powder coating material 
A was coated thereon so as to give a dry film thickness of 80.mu. and 
baked at 170.degree. C. for 30 minutes. The coating film thus obtained had 
excellent finished appearance and sharpness and was good in coating film 
performances, such as solvent resistance, water resistance, weather 
resistance, etc. as indicated in Table 1, and useful as a solid color 
coating film for automobiles. 
The above-mentioned base coating material had a good pigment 
dispersibility, a good pulverizability at the time of coating and a good 
coating workability. 
Comparative Example 1 
In place of the base coating material of Example 1, a base coating material 
having the following formulation was prepared: 
______________________________________ 
Dianal HR-560 (manufactured by 
Mitsubishi Rayon K.K., solid 
content 50%) 42 parts 
Uban 20 SE 15 parts 
Alpaste #1190 MA 8 parts 
Colofine blue #720 2 parts 
______________________________________ 
Then, a 2-coat 1-bake coating film was prepared from the above-mentioned 
base coating material by carrying out coating and baking in the same 
manner as in Example 1. The coating film thus obtained had a bad 
appearance with occurrence of metallic unevenness and pin hole as 
indicated in Table 1. 
Comparative Example 2 
In place of the base coating material of Example 1, a base coating material 
having the following formulation was prepared: 
______________________________________ 
Acrylic copolymer A (50% solid content) 
42 parts 
Uban 20 SE 15 parts 
15% Solution of EAB-551-02 in 
Cellosolve acetate 20 parts 
Alpaste #1190 MA 8 parts 
Colofine blue #720 2 parts 
______________________________________ 
Then, a 2-coat 1-bake coating film was prepared from the above-mentioned 
base coating material by carrying out coating and baking in the same 
manner as in Example 1. The coating film thus obtained had pin holes and 
bad finished appearance. 
Comparative Example 3 
In place of the base coating material of Example 1, a base coating material 
having the following formulation was prepared: 
______________________________________ 
Acrylic copolymer A (5% solid content) 
54 parts 
15% Solution of EAB-551-02 in 
Cellosolve acetate 20 parts 
Alpaste #1109 MA 8 parts 
Colofine blue #720 2 parts 
______________________________________ 
Then, a 2-coat 1-bake coating film was prepared from the above-mentioned 
based coating material by carrying out coating and baking in the same 
manner as in Example 1. The coating film thus obtained had a good finished 
appearance but was remarkably inferior in solvent resistance, water 
resistance and the like as indicated in Table 1. 
TABLE 1 
__________________________________________________________________________ 
Result of Estimation of Coating Workability and 
Coating Film Performances 
No. 
Comparative 
Example Example 
Item 1 2 3 4 5 6 7 8 9 10 1 2 3 
__________________________________________________________________________ 
Finished 
appearance 
.circle. 
.circle. 
.circle. 
.circle. 
.circleincircle. 
.circleincircle. 
.circleincircle. 
.circleincircle. 
.circleincircle. 
.circleincircle. 
x x .circleincircle. 
Flexibility 
.circle. 
.circle. 
.circle. 
.circle. 
.circle. 
.circle. 
.circle. 
.circle. 
.circle. 
.circle. 
.circle. 
.circle. 
.DELTA. 
Solvent 
resistance 
.circle. 
.circle. 
.circleincircle. 
.circleincircle. 
.circleincircle. 
.circleincircle. 
.circleincircle. 
.circleincircle. 
.circleincircle. 
.circleincircle. 
.circleincircle. 
.circleincircle. 
x 
Water 
resistance 
.circle. 
.circle. 
.circle. 
.circle. 
.circle. 
.circle. 
.circle. 
.circle. 
.circle. 
.circle. 
.circle. 
.circle. 
x 
Adhesion to 
primer .circle. 
.circle. 
.circleincircle. 
.circleincircle. 
.circle. 
.circle. 
.circle. 
.circleincircle. 
.circleincircle. 
.circle. 
.circle. 
.circle. 
.DELTA. 
__________________________________________________________________________ 
Note: 
.circleincircle.: Excellent 
.circle.: Good 
.DELTA.: Poor 
x: Bad 
Method of estimation 
Finished appearance: Judged based on pin hole, orientation of metallic 
powder and the like. 
Flexibility: Judged by Erichsen test 
Solvent resistance: Judged by gasoline dipping test (dipped at 20.degree. 
C. for 24 hrs.) 
Water resistance: Judged by hot water dipping test (dipped at 80.degree. 
C. for 48 hrs.) 
Adhesion to primer: Judged by chipping test.