Polypropylene resin composition and method for coating molded products of the resin composition

Herein provided are a polypropylene resin composition which comprises (A) a polypropylene, (B) an ethylene-propylene-diene terpolymeric rubber having a Mooney viscosity, ML.sub.1+4 (100.degree. C.), ranging from 5 to 50 and an iodine value of not less than 15, the content of the component (B) ranging from 10 to 50% by weight on the basis of the total weight of the components (A) and (B), and optionally (C) an inorganic filler in an amount ranging from 0 to 40 parts by weight per 100 parts by weight of the sum of the components (A) and (B); a coating method which comprises the steps of applying a primer coating to a molded product obtained by molding the foregoing polypropylene resin composition or irradiating the molded product with plasma without degreasing and washing the product with a halogen atom-containing organic solvent and then applying a top coat to the product; and a coating method which comprises the steps of degreasing and washing a molded product obtained by molding the foregoing polypropylene resin composition and then applying a top coat to the product without applying a primer coating to the molded product or irradiating the molded product with plasma. The coated film obtained according to the foregoing methods has good bond strength to the molded product.

BACKGROUND OF THE INVENTION 
Field of the Invention 
The present invention relates to a polypropylene resin composition which 
can be readily coated, in particular an impact-resistant polypropylene 
resin composition suitably used in making exterior automotive trims such 
as a bumper and a method for coating a molded product of the polypropylene 
resin composition, in particular, an exterior automotive trim such as a 
bumper. 
Description of the Related Art 
Polypropylene resins have been widely used in various fields because of low 
specific gravity and high rigidity as well as their excellent heat 
resistance and resistance to chemical attack. However, it has been known 
that the polypropylene resins have insufficient capacity of being coated 
since they are non-polar by nature. For instance, when an automotive 
bumper of polypropylene is coated, the bumper must be degreased and washed 
with a halogen atom-containing organic solvent such as 
1,1,1-trichloroethane, then coated with a primer layer as an underlying 
coating or irradiated with plasma and thereafter a top coat must be 
applied thereto in order to achieve a sufficient bond strength to the 
coating layer. 
The foregoing coating techniques require many processes and are not 
economical from the viewpoint of treating time. In addition, it is feared 
that the halogen atom-containing organic solvents used for degreasing and 
washing the polypropylene resin articles may adversely affect the human 
body and environment and correspondingly it has been desired for the 
immediate development of a means for solving this problem. Moreover, it 
can be appreciated that the coating methods conventionally carried out are 
quite uneconomical while taking the time and expense devoted in the 
treatment of waste liquid into consideration. 
Under such circumstances, there have been proposed, from the viewpoint of 
reduction in the number of coating processes and of labor savings, various 
techniques which make it possible to delete the process for applying an 
underlying coating or which are adapted for so-called primer-less coating 
in the coating of automotive bumpers of polypropylene. For instance, there 
have been known (1) methods in which a compound having a polar group is 
grafted on polypropylene (Japanese Patent Unexamined publication 
(hereinafter referred to as "J. P. KOKAI") Nos. Sho 62-64848 and Sho 
62-119243); and (2) methods in which a polar substance is blended with 
polypropylene (J. P. KOKAI Nos. Sho 51-145553 and Sho 61-89239). 
However, the methods (1) in which a compound having a polar group is 
grafted onto polypropylene suffer from such problems that the compounds 
used therein are toxic and that physical properties of the resulting resin 
composition are impaired. Moreover, the bond strength to a coating applied 
to the polypropylene articles is still insufficient. The methods (2) in 
which a polar substance is blended with polypropylene simply provide a 
polypropylene article having a bond strength which is insufficient for use 
as a material for making bumpers. 
Further, both the methods (1) and (2) include a process for degreasing and 
washing polypropylene articles with a solvent (1,1,1-trichloroethane) as 
an indispensable process and, therefore, it is necessary to work out 
measures to solve the problems of detrimental effects of solvents on the 
human body and environments and of the treatment of waste liquid. 
SUMMARY OF THE INVENTION 
Accordingly, an object of the present invention is to provide an 
impact-resistant polypropylene resin composition which permits the 
application of a top coat after applying a primer layer or irradiating 
with plasma without degreasing and washing with a halogen atom-containing 
solvent such as 1,1,1-trichloroethane; or after degreasing and washing 
without applying any primar layer or without irradiating with plasma and 
which is extremely adapted for the production of molded products whose 
bond stength against a coating film of a paint or varnish for top coats, 
in particular, an impact-resistant polypropylene resin composition which 
is excellent in capacity of being coated and is suitably used in making 
exterior automotive trims such as bumpers as well as a method for coating 
a molded product obtained by molding the resin composition. 
Under such circumstances, the inventors of this invention have conducted 
intensive investigations, and as a result have found out that a 
composition comprising polypropylene which is blended with a specific 
ethylene-propylene-diene terpolymer in a specific compounding ratio 
permits the application of a top coat after applying a primer layer or 
irradiating with plasma without degreasing and washing with a halogen 
atom-containing solvent such as 1,1,1-trichloroethane; or after degreasing 
and washing without applying any primer layer or without irradiating with 
plasma and is excellent in bond strength with a coating film of a paint or 
varnish for top coats and thus have completed the present invention. 
The present invention thus relates to a polypropylene resin composition 
which can be readily coated which comprises (A) polypropylene and (B) an 
ethylene-propylene-diene terpolymeric rubber having a Mooney viscosity, 
ML.sub.1+4 (100.degree.0 C.), ranging from 5 to 50 and an iodine value of 
not less than 15, in which the content of the component (B) ranges from 10 
to 50% by weight on the basis of the total weight of the components (A) 
and (B) and which optionally comprises (C) an inorganic filler in an 
amount ranging from 0 to 40 parts by weight per 100 parts by weight of the 
sum of the components (A) and (B). 
The present invention also relates to a method for coating a molded product 
obtained by molding the polypropylene resin composition, which comprises 
the steps of applying a primer layer to the molded product or irradiating 
the product with plasma and then applying a top coat thereto without 
degreasing and washing the product with a halogen atom-containing organic 
solvent. 
In addition, the present invention relates to a method for coating a molded 
product obtained by molding the polypropylene resin composition, which 
comprises the steps of degreasing and washing the molded product and then 
applying a top coat thereto without applying any primer layer to the 
molded product or without irradiating the product with plasma.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The polypropylene used in the present invention may be any crystalline 
polypropylene and may be a homopolymer of propylene or a random or block 
copolymer of propylene with ethylene and/or an .alpha.-olefin. The term 
".alpha.-olefin" herein means, for instance, butene-1, pentene-1, hexene-1 
and 4-methylpentene-1 which can be used alone or in any combination 
thereof in the present invention. 
In the present invention, it is desirable to use homopolymers of propylene 
or random or block copolymers of propylene with ethylene. Preferably used 
in the present invention are propylene-ethylene block copolymers, in 
particular those having an ethylene content ranging from 5 to 25% by 
weight and a melt index (MI) ranging from 0.1 to 100 g/10 min (as 
determined according to ASTM D-1238 at 230.degree. C.). 
The ethylene-propylene-diene terpolymeric rubber used in the present 
invention has a Mooney viscosity, ML.sub.1+4 (100.degree. C.) ranging from 
5 to 50, preferably 10 to 30 and an iodine value of not less than 15, 
preferably 17 to 25 and more preferably 21 to 25. 
If the Mooney viscosity ML.sub.1+4 (100.degree. C.) of the terpolymeric 
rubber is less than 5, the molded product obtained from the resin 
composition has bad surface appearance. On the other hand, if it exceeds 
50, not only the bond strength is lowered but also the molding properties 
and the appearance of the resulting molded product are impaired. 
If the iodine value of the foregoing terpolymeric, rubber is less than 15, 
a sufficient bond strength with coated films cannot be ensured when the 
molded product of the resin composition is coated with a primer layer or 
irradiated with plasma, but is not degreased and washed with a halogen 
atom-containing organic solvent such as 1,1,1-trichloroethane or when the 
molded product is degreased and washed with such an organic solvent, but 
is neither coated with any primer layer nor irradiated with plasma. 
The propylene content of the foregoing terpolymeric rubber preferably 
ranges from 15 to 50% by weight. This is because if it is less than 15% by 
weight, the impact resistance and the capacity of the resulting molded 
product too be coated are lowered, while if it is more than 50% by weight, 
the productivity and quality of the ethylene-propylene-diene rubber 
obtained are impaired, which makes the handling thereof difficult and the 
resulting copolymer is not practically acceptable. 
As the diene component for the foregoing terpolymeric rubber, there may be 
used, for instance, dicyclopentadiene, ethylidene norbornene and 
1,4-hexadiene. Among these, preferred are dicyclopentadiene and ethylidene 
norbornene and in particular dicyclopentadiene. 
The resin composition of the present invention should have a content of the 
component (B) ranging from 10 to 50% by weight and preferably 25 to 40% by 
weight on the basis of the total weight of the components (A) and (B). 
This is because if the content of the component (B) is less than 10% by 
weight, the impact resistance and the capacity of the resulting molded 
product to be coated are lowered, while if it is more than 50% by weight, 
the rigidity thereof is impaired. 
In the present invention, an inorganic filler may optionally be used. The 
inorganic fillers usable in the present invention are powdery inorganic 
fillers and specific examples thereof are whiskers of calcium oxide, 
magnesium oxide, aluminum hydroxide, calcium hydroxide, magnesium 
hydroxide, magnesium carbonate, calcium silicate, magnesium silicate, 
calcium sulfate, calcium carbonate, barium sulfate, calcium sulfite, talc, 
clay, glass, basic magnesium carbonate, dolomite, wollastonite, as well as 
potassium titanate and magnesium sulfate, but the use of calcium 
carbonate, barium sulfate, calcium silicate and talc is particularly 
preferred, when taking the balance between the impact strength and the 
rigidity of the resulting composition into consideration. The inorganic 
filler usable in the present invention preferably has an average particle 
size of not more than 5 .mu.m from the viewpoint of the impact resistance 
of the resulting composition. 
The polypropylene resin composition of the present invention may comprise 
an inorganic filler in an amount ranging from 0 to 40 parts by weight, 
preferably 10 to 30 parts by weight per 100 parts by weight of the sum of 
the components (A) and (B). If the amount of the inorganic filler to be 
added exceeds 40 parts by weight, the impact resistance and the capacity 
of the resulting resin composition to be coated and hence the molded 
product are lowered, in particular blisters are formed between a resin 
layer and a coated film due, to the moisture absorbed by the inorganic 
filler present in the resin and the resistance to hot water and resistance 
to humidity of the resulting product are accordingly impaired. 
The inorganic fillers used in the present invention may be surface-treated 
and the surface treatment can be performed by the use of, for instance, a 
surface treating agent such as a variety of silane and titanate coupling 
agents; or a surface treating agent derived from a higher fatty acid or an 
unsaturated organic acid. 
These surface treatments are effective for improving a variety of physical 
properties such as mixing properties, molding properties, self-tapping 
strength and weld strength of the resulting composition in addition to the 
foregoing intended effects of the invention. 
The polypropylene resin may further comprise at least one additive commonly 
used in polypropylene resins such as antioxidants, heat stabilizers, 
ultraviolet light absorbers, flame retardants, nucleating agents, organic 
inorganic pigments in an amount which does not adversely affect the 
effects of the present invention. 
The polypropylene resin composition of the present invention can be 
obtained by mixing the foregoing components with a mixer commonly employed 
in this field, for instance, Henschel mixer, then kneading the mixture 
with, for instance, a single screw extruder, twin-screw extruder, a roll 
or a Banbury mixer and then forming it into pellets. 
The polypropylene resin composition thus obtained can be formed into a 
desired molded product by any conventional molding method such as an 
injection molding method, an extrusion molding method or a compression 
molding method. 
In the first embodiment of the method for coating the molded product 
obtained from the resin composition which comprises the steps of applying 
a primer layer to the molded product or irradiating the product with 
plasma and then applying a top coat thereto without degreasing and washing 
the product with a halogen atom-containing organic solvent, it is not 
necessary to perform degreasing and washing with a halogen atom-containing 
organic solvent, but the molded product may optionally be degreased and 
washed with a solvent other than halogen atom-containing organic solvents. 
This results in further improvement in the effects of the present 
invention. 
Examples of the foregoing solvents other than halogen atom-containing 
organic solvents are lower alcohols represented by isopropyl alcohol and 
surfactant-containing aqueous solutions of alkalis or acids. 
As paints or varnishes for forming an underlying coating as a primer layer 
used in the first embodiment of the method of the present invention, a 
variety of paints and varnishes represented by two-pack type 
acryl-chlorinated polypropylene paints or varnishes for underlying coating 
can be commercially available. After preparing a paint for the primer 
layer in accordance with each specification, it is applied onto the molded 
product with a film thickness of the order of 15 .mu.m and then baked and 
dried by heating, for instance, at 90.degree. C. for 30 minutes. 
The surface-treatment with plasma can be performed by bringing the surface 
of the molded product in contact with the plasma which is generated by 
excitation of oxygen, nitrogen, other inert gases or mixtures thereof 
through irradiation with high frequency or microwave discharge. The 
conditions for the generation of plasma vary depending on the kinds of the 
gases used, but are in general a pressure ranging from 0.1 to 5 Torr; a 
microwave power output ranging from 600 to 1200 W; and a treating time 
ranging from 5 to 600 seconds. It is a matter of course that the treating 
time may sometimes be extended and the shape of the treating chamber may 
also be changed according to the shape of the molded product. 
In the second embodiment of the method for coating a molded product 
obtained by molding the polypropylene resin composition according to the 
present invention, which comprises the steps of degreasing and washing the 
molded product and then applying a top coat thereto without applying any 
primer layer to the molded product or without irradiating the product with 
plasma, the resulting molded product is first degreased and washed. The 
term "degreasing and washing of the product" herein used means the removal 
of anti-corrosive agents for molds, releasing agents, machine oils which 
are possibly adhered to the surface of the product as well as sebum which 
is possibly adhered to the product during handling the same. 
The degreasing and washing can be performed according to any conventionally 
known method. The degreasing and washing may be performed by, for 
instance, bringing the molded product in contact with liquid or steam of a 
halogen atom-containing organic solvent such as 1,1,1-trichloroethane or 
trichloroethylene; or an aromatic organic solvent such as benzene, 
toluene, xylene or chlorobenzene, for 10 to 300 seconds. Then the molded 
product is allowed to stand in an atmosphere maintained at a temperature 
ranging from 40.degree. to 100.degree. C. for 60 to 600 seconds to remove 
the organic solvent adhered to the product. Alternatively, the degreasing 
and washing can also be performed by washing the surface of the product 
with a lower alcohol such as isopropyl alcohol or a surfactant-containing 
aqueous solution of an alkali or an acid. 
In the second embodiment of the coating method according to the present 
invention, it is not necessary to apply a primer layer to the molded 
product or to irradiate it with plasma. Therefore, a top coat is applied 
to the product subsequently with the foregoing degreasing and washing. 
A variety of paints and varnishes for top coats such as two-pack type 
urethane paints or varnishes and one-pack type alkyd-melamine resin paints 
or varnishes are commercially available. 
Examples of paints and varnishes for the top coat used in the exterior 
automotive trims are various kinds of two-pack type urethane resin paints 
and varnishes (film thickness: 100 .mu.m; baked and dried at 80.degree. C. 
for 40 minutes) and one-pack type alkyd-melamine resin paints or varnishes 
(film thickness: 100 .mu.m; baked and dried at 120.degree. C. for 40 
minutes) having a variety of colors. After coating the top coat, the 
molded product is allowed to stand at room temperature for 48 hours to 
harden the coated film and to thus give a coated and molded product. 
EXAMPLES 
The present invention will hereunder be explained in more detail with 
reference to the following Examples, but the following Examples are given 
for only illustrative purposes and do not in any way limit the scope of 
the present invention. 
EXAMPLES 1 TO 6 
There were blended and mixed in a Henschel mixer, 70 parts by weight of a 
crystalline ethylene-propylene block copolymer (hereunder referred to as 
"PP-A") having an ethylene content of 9.8% by weight, boiling 
n-heptane-insoluble matter of 95.8% by weight and a melt flow index (MI) 
of 8.6 g/10 min (as determined according to ASTM D-1238, at 230.degree. 
C.), 70 parts by weight of an ethylene-propylene random copolymer 
(hereunder referred to as "PP-B") having an ethylene content of 4.0% by 
weight and a melt flow index (MI) of 8.0 g/10 min or 70 parts by weight of 
a propylene homopolymer (hereunder referred to as "PP-C") having a melt 
flow index (MI) of 8.0 g/10 min, as a polypropylene component; 30 parts by 
weight of an ethylene-propylene-diene terpolymeric rubber (hereunder 
referred to as "EPDM-A") having a propylene content of 30% by weight, a 
Mooney viscosity, ML.sub.1+4 (100.degree. C.), of 20 and an iodine value 
of 22 and whose diene component is dicyclopentadiene or 30 parts by weight 
of an ethylene-propylene-diene terpolymeric rubber (hereunder referred to 
as "EFDM-B") having a propylene content of 28% by weight, a Mooney 
viscosity, ML.sub.1+4 (100.degree. C.), of 22 and an iodine value of 23 
and whose diene component is ethylidene norbornene, as a terpolymeric 
rubber component; 0.05 part by weight of 2,6-di-t-butyl-4-methylphenol 
(hereunder referred to as "Stabilizer-A" ), 0.1 part by weight of calcium 
stearate (hereunder referred to as "Stabilizer-B") and 0.1 part by weight 
of tetrakis- (methylene-3-(3',5'-di t-butyl-4-hydroxyphenyl)propionate) 
-methane (hereunder referred to as "Stabilizer-C") as stabilizers, the 
resulting mixture was pelletized with an extruder having a diameter of 40 
mm which was maintained at 230.degree. C. and the resulting resin 
composition was injection-molded to give a test piece (a flat plate having 
a size of 80.times.160.times.2 mm . Then a two-pack type 
acrylic-chlorinated polypropylene paint or varnish for underlying coating 
was applied onto the foregoing test piece in a film thickness of 10 .mu.m, 
dried at 80.degree. C. for 30 minutes, a two-pack type urethane paint or 
varnish for top coat was applied to the underlying coating in a thickness 
of 50 .mu.m, baked and dried at 80.degree. C. for 40 minutes, followed by 
allowing to stand at room temperature for 48 hours to give a coated 
article. After making, the coated article on the coated film of the coated 
article, a cut having a width of 1.0 cm was made with a cutter knife, the 
180.degree. peel strength (kg/cm) of the coated film was determined at a 
speed of 30 mm/min with an Instron tensile tester. Moreover, the notched 
test piece was subjected to the Izod impact test according to JIS K-7110 
to determine Izod impact strength (kg . cm/cm). The results thus obtained 
are summarized in the following Table 1. In Table 1, "NB" appearing in the 
column of "Izod impact strength" means that the corresponding test piece 
was not broken even at an impact of 40 kg . cm /cm, in other words the 
Izod impact strength was more than 40 kg . cm /cm. 
EXAMPLES 7 TO 12 
The same procedures and tests used in Examples 1 to 6 were repeated except 
that a one-pack type alkyd-melamine resin paint was used as a paint for 
top coat and it was baked and dried at 120.degree. C. for 40 minutes. The 
results obtained are listed in the following Table 2. 
EXAMPLES 13 TO 24 
The same procedures and tests used in Examples 1 to 12 were repeated except 
that the test piece was irradiated with plasma under the following 
conditions instead of the application of a primer coating. The results 
obtained are listed in the following Tables 3 and 4. 
______________________________________ 
(Conditions for the Plasma Treatment) 
______________________________________ 
(1) Apparatus for plasma treatment: Microwave Plasma 
Treating Apparatus (TMZ-202 6M; available from 
Toshiba Corporation) 
(2) Treating gas: oxygen 
(3) Treating time: 5 seconds 
(4) Inner pressure of the treating chamber: 
1.0 Torr 
(5) Gas flow rate: 480 cc/min 
(6) Microwave power output: 900 W. 
______________________________________ 
EXAMPLES 25 TO 30 
The same procedures and tests used in Examples 1, 7, 13 and 19 were 
repeated except that 70 parts by weight of PP-A was used as a 
polypropylene component, that 30 parts by weight of EPDM-A or EPDM-B was 
used as a terpolymeric rubber component and that 10, 20 or 30 parts by 
weight of talc was used as an inorganic filler. The results obtained are 
listed in the following Table 5. 
COMATIVE EXAMPLES 1 TO 3 
The same procedures and tests used in Examples 1, 7, 13 and 19 were 
repeated except that 100 parts by weight of PP-A, PP-B or PP-C without 
using any terpolymeric rubber component and that the resulting test piece 
was exposed to an atmosphere saturated with 1,1,1-trichloroethane for 100 
seconds to perform washing with an organic solvent and then allowed to 
stand for 10 minutes in an oven maintained at 100.degree. C. to remove the 
organic solvent. The results obtained are listed in the following Table 6. 
COMATIVE EXAMPLES 4 TO 6 
The same procedures and tests used in Comparative Examples 1 to 3 were 
repeated except that the application of a top coat was performed 
immediately after the molding of test pieces without washing with 
1,1,1-trichloroethane. The results obtained are listed in the following 
Table 6. 
COMATIVE EXAMPLES 7 TO 9 
The same procedures and tests used in Comparative Example 4 were repeated 
except that talc was used in an amount of 10, 20 or 30 parts by weight per 
100 parts by weight of PP-A. The results obtained are listed in the 
following Table 7. 
COMATIVE EXAMPLES 10 TO 15 
The same procedures and tests used in Comparative Example 4 were separated 
except that an ethylene-propylene-diene terpolymeric rubber (hereunder 
referred to as "EPDM-C") having a propylene content of 30% by weight, a 
Mooney viscosity, ML.sub.1+4 (100.degree. C.), of 20 and an iodine value 
of 10 and whose diene component as the third component is 
dicyclopentadiene or an ethylene-propylene-diene terpolymeric rubber 
(hereunder referred to as "EPDM-D") having a propylene content of 28% by 
weight, a Mooney viscosity, ML.sub.1+4 (100.degree. C.), of 22 and an 
iodine value of 11 and whose diene component as the third component is 
ethylidene norbornene was used in an amount (part by weight) as listed in 
the following Table 8. The results obtained are listed in the following 
Table 8. 
COMATIVE EXAMPLES 16 TO 21 
The same procedures and tests used in Comparative Example 4 were repeated 
except that PP-A and an ethylene-propylene-diene terpolymeric rubber 
(hereunder referred to as "EPDM-E") having a propylene content of 30% by 
weight, a Mooney viscosity, ML.sub.1+4 (100.degree. C.), of 55 and an 
iodine value of 19 and whose diene component as the third component is 
dicyclopentadiene or an ethylene-propylene-diene terpolymeric rubber 
(hereunder referred to as "EPDM-F") having a propylene content of 28% by 
weight, a Mooney viscosity, ML.sub.1+4 (100.degree. C.), of 57 and an 
iodine value of 21 and whose diene component as the third component is 
ethylidene norbornene were used in amounts (part by weight) as listed in 
the following Table 9. The results, obtained are listed in the following 
Table 9. In each case, the gloss and appearance of the resulting molded 
product were insufficient and it was liable to cause defects. 
EXAMPLES 31 TO 36 
There were blended and mixed in a Henschel mixer, 70 parts by weight of 
PP-A, PP-B or PP-C as a polypropylene component; 30 parts by weight of 
EPDM-A or EPDM-B as a terpolymeric rubber component; and 0.05 part by 
weight of Stabilizer-A, 0.1 part by weight of Stabilizer-B and 0.1 part by 
weight of Stabilizer-C as stabilizers, the resulting mixture was 
pelletized with an extruder having a diameter of 40 mm maintained at 
230.degree. C. and the resulting resin composition was formed into a test 
piece (a flat plate having a size of 80.times.160.times.2 mm) through 
injection molding. Then the test piece was washed with an organic solvent 
by exposing it to an atmosphere saturated with 1,1,1-trichloroethane for 
100 seconds and thereafter allowed to stand for 10 minutes in an oven 
maintained at 100.degree. C. to thus remove the organic solvent. 
Subsequently, a two-pack type urethane paint for top coat was applied onto 
the test piece so that the thickness thereof was equal to 50 .mu.m, baked 
and dried at 80.degree. C. for 30 minutes and then allowed to stand at 
room temperature for 48 hours to thus give a coated product. After making 
the coated article, on the coated film of the coated product, a cut having 
a width of 1.0 cm was made with a cutter knife, the 180.degree. peel 
strength (kg/cm) of the coated film was determined at a speed of 30 
mm/min with an Instron tensile tester. The results thus obtained are 
summarized in the following Table 10. 
EXAMPLES 37 TO 42 
The same procedures and tests used in Examples 31 to 36 were repeated 
except that a one-pack type alkyd-melamine resin paint was used as a paint 
for top coat and it was baked and dried at 120.degree. C. for 30 minutes. 
The results obtained are listed in the following Table 11. 
EXAMPLES 43 TO 48 
The same procedures and tests used in Examples 31 and 37 were repeated 
except that 70 parts by weight of PP-A was used as a polypropylene 
component, that 30 parts by weight of EPDM-A or EPDM-B was used as a 
terpolymeric rubber component and that 10, 20 or 30 parts by weight of 
talc was used as an inorganic filler. The results obtained are listed in 
the following Table 12. 
EXAMPLES 49 TO 54 
The same procedures and tests used in Examples 31, 34, 37 and 40 were 
repeated except that the degreasing and washing of the test piece was 
performed by wiping with a cloth dampened with isopropyl alcohol, a 
surfactant-containing phosphoric acid aqueous solution or benzene. The 
results thus obtained are listed in the following Table 13. 
COMATIVE EXAMPLES 22 TO 24 
The same procedures and tests used in Examples 31 and 37 were repeated 
except that the terpolymeric rubber component was not used and 100 parts 
by weight of PP-A, PP-B or PP-C was used. The wash of the resulting test 
piece with an organic solvent was performed by exposing it in an 
atmosphere saturated with 1,1,1-trichloroethane for 100 seconds and then 
the test piece was allowed to stand in an oven maintained at 100.degree. 
C. for 10 minutes to thus remove the organic solvent. The results thus 
obtained are listed in the following Table 14. 
COMATIVE EXAMPLES 25 TO 27 
The same procedures and tests used in Comparative Examples 22 were repeated 
except that talc was added to the resin composition in an amount of 10, 20 
or 30 parts by weight per 100 parts by weight of PP-A. The results thus 
obtained are listed in the following Table 15. 
COMATIVE EXAMPLES 28 TO 33 
The same procedures and tests used in Comparative Examples 22 were repeated 
except that PP-A and EPDM-C or EPDM-D were used in the amounts (part by 
weight) as listed in the following Table 16. The results thus obtained are 
listed in Table 16. 
COMATIVE EXAMPLES 34 TO 39 
The same procedures and tests used in Comparative Examples 22 were repeated 
except that PP-A and EPDM-E or EPDM-F were used in the amounts (part by 
weight) as listed in the following Table 17. The results thus obtained are 
listed in Table 17. In each case, the gloss and the appearance of the 
resulting molded product were insufficient and the product was liable to 
cause defects. 
TABLE 1 
______________________________________ 
Example No. 
1 2 3 4 5 6 
______________________________________ 
PP-A 70 70 
PP-B 70 70 
PP-C 70 70 
EPDM-A 30 30 30 
EPDM-B 30 30 30 
Stabilizer-A 0.05 0.05 0.05 0.05 0.05 0.05 
Stabilizer-B 0.1 0.1 0.1 0.1 0.1 0.1 
Stabilizer-C 0.1 0.1 0.1 0.1 0.1 0.1 
TCE Degreasing .multidot. 
No No No No No No 
Washing Process 
Primer Coating Did Did Did Did Did Did 
Peel Strength of Coated 
1.35 1.30 1.20 0.85 0.80 0.80 
Film 
Izod Impact Strength 
NB NB NB NB NB NB 
______________________________________ 
TABLE 2 
______________________________________ 
Example No. 
7 8 9 10 11 12 
______________________________________ 
PP-A 70 70 
PP-B 70 70 
PP-C 70 70 
EPDM-A 30 30 30 
EPDM-B 30 30 30 
Stabilizer-A 0.05 0.05 0.05 0.05 0.05 0.05 
Stabilizer-B 0.1 0.1 0.1 0.1 0.1 0.1 
Stabilizer-C 0.1 0.1 0.1 0.1 0.1 0.1 
TCE Degreasing .multidot. 
No No No No No No 
Washing Process 
Primer Coating Did Did Did Did Did Did 
Peel Strength of Coated 
1.30 1.20 1.15 0.90 0.85 0.85 
Film 
Izod Impact Strength 
NB NB NB NB NB NB 
______________________________________ 
TABLE 3 
______________________________________ 
Example No. 
13 14 15 16 17 18 
______________________________________ 
PP-A 70 70 
PP-B 70 70 
PP-C 70 70 
EPDM-A 30 30 30 
EPDM-B 30 30 30 
Stabilizer-A 0.05 0.05 0.05 0.05 0.05 0.05 
Stabilizer-B 0.1 0.1 0.1 0.1 0.1 0.1 
Stabilizer-C 0.1 0.1 0.1 0.1 0.1 0.1 
TCE Degreasing .multidot. 
No No No No No No 
Washing Process 
Irradiation with Plasma 
Did Did Did Did Did Did 
Peel Strength of Coated 
1.25 1.20 1.20 0.90 0.85 0.85 
Film 
Izod Impact Strength 
NB NB NB NB NB NB 
______________________________________ 
TABLE 4 
______________________________________ 
Example No. 
19 20 21 22 23 24 
______________________________________ 
PP-A 70 70 
PP-B 70 70 
PP-C 70 70 
EPDM-A 30 30 30 
EPDM-B 30 30 30 
Stabilizer-A 0.05 0.05 0.05 0.05 0.05 0.05 
Stabilizer-B 0.1 0.1 0.1 0.1 0.1 0.1 
Stabilizer-C 0.1 0.1 0.1 0.1 0.1 0.1 
TCE Degreasing .multidot. 
No No No No No No 
Washing Process 
Irradiation with Plasma 
Did Did Did Did Did Did 
Peel Strength of Coated 
1.30 1.25 1.25 0.90 0.85 0.85 
Film 
Izod Impact Strength 
NB NB NB NB NB NB 
______________________________________ 
TABLE 5 
______________________________________ 
Example No. 
25 26 27 28 29 30 
______________________________________ 
PP-A 70 70 70 70 70 70 
EPDM-A 30 30 30 
EPDM-B 30 30 30 
Talc 10 20 30 10 20 30 
Stabilizer-A 0.05 0.05 0.05 0.05 0.05 0.05 
Stabilizer-B 0.10 0.10 0.10 0.10 0.10 0.10 
Stabilizer-C 0.10 0.10 0.10 0.10 0.10 0.10 
TCE Degreasing .multidot. 
No No No No No No 
Washing Process 
Peel Strength of Coated 
Film: 
One-pack Type 
Primer-Coated Product 
1.25 1.20 1.20 0.90 0.90 0.85 
Plasma-Irradiated Product 
1.25 1.15 1.20 0.90 0.95 0.90 
Peel Strength of Coated 
Film: 
Two-pack Type 
Primer-Coated Product 
1.20 1.20 1.15 0.90 0.85 0.85 
Plasma-Irradiated Product 
1.25 1.20 1.20 0.90 0.80 0.85 
Izod Impact Strength 
NB NB NB NB NB NB 
______________________________________ 
TABLE 6 
__________________________________________________________________________ 
Comparative Example No. 
1 2 3 4 5 6 
__________________________________________________________________________ 
PP-A 100 100 
PP-B 100 100 
PP-C 100 100 
Stabilizer-A 0.05 
0.05 
0.05 
0.05 
0.05 
0.05 
Stabilizer-B 0.10 
0.10 
0.10 
0.10 
0.10 
0.10 
Stabilizer-C 0.10 
0.10 
0.10 
0.10 
0.10 
0.10 
TCE Degreasing .multidot. Washing Process 
Did Did Did No No No 
Peel Strength of Coated Film: 
One-pack Type 
Primer-Coated Product 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
Plasma-Irradiated Product 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
Peel Strength of Coated Film: 
Two-pack Type 
Primer-Coated Product 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
Plasma-Irradiated Product 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
Izod Impact Strength 
8 2 2 8 2 2 
__________________________________________________________________________ 
TABLE 7 
______________________________________ 
Comparative Example No. 
7 8 9 
______________________________________ 
PP-A 100 100 100 
Talc 10 20 30 
Stabilizer-A 0.05 0.05 0.05 
Stabilizer-B 0.10 0.10 0.10 
Stabilizer-C 0.10 0.10 0.10 
TCE Degreasing .multidot. Washing Process 
No No No 
Peel Strength of Coated Film: 
One-pack Type 
Primer-Coated Product 
&lt;0.3 &lt;0.3 &lt;0.3 
Plasma-Irradiated Product 
&lt;0.3 &lt;0.3 &lt;0.3 
Peel Strength of Coated Film: 
Two-pack Type 
Primer-Coated Product 
&lt;0.3 &lt;0.3 &lt;0.3 
Plasma-Irradiated Product 
&lt;0.3 &lt;0.3 &lt;0.3 
Izod Impact Strength 
4 3.5 3 
______________________________________ 
TABLE 8 
__________________________________________________________________________ 
Comparative Example No. 
10 11 12 13 14 15 
__________________________________________________________________________ 
PP-A 90 80 70 90 80 70 
EPDM-C 10 20 30 
EPDM-D 10 20 30 
Stabilizer-A 0.05 
0.05 
0.05 
0.05 
0.05 
0.50 
Stabilizer-B 0.10 
0.10 
0.10 
0.10 
0.10 
0.10 
Stabilizer-C 0.10 
0.10 
0.10 
0.10 
0.10 
0.10 
TCE Degreasing .multidot. Washing Process 
No No No No No No 
Peel Strength of Coated Film: 
One-pack Type 
Primer-Coated Product 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
Plamsa-Irradiated Product 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
Peel Strength of Coated Film: 
Two-pack Type 
Primer-Coated Product 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
Plamsa-Irradiated Product 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
Izod Impact Strength 
NB NB NB NB NB NB 
__________________________________________________________________________ 
TABLE 9 
__________________________________________________________________________ 
Comparative Example No. 
16 17 18 19 20 21 
__________________________________________________________________________ 
PP-A 90 80 70 90 80 70 
EPDM-E 10 20 30 
EPDM-F 10 20 30 
Stabilizer-A 0.05 
0.05 
0.05 
0.05 
0.05 
0.50 
Stabilizer-B 0.10 
0.10 
0.10 
0.10 
0.10 
0.10 
Stabilizer-C 0.10 
0.10 
0.10 
0.10 
0.10 
0.10 
TCE Degreasing .multidot. Washing Process 
No No No No No No 
Peel Strength of Coated Film: 
One-pack Type 
Primer-Coated Product 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
Plamsa-Irradiated Product 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
Peel Strength of Coated Film: 
Two-pack Type 
Primer-Coated Product 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
Plamsa-Irradiated Product 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
Izod Impact Strength 
NB NB NB NB NB NB 
__________________________________________________________________________ 
TABLE 10 
______________________________________ 
Example No. 
31 32 33 34 35 36 
______________________________________ 
PP-A 70 70 
PP-B 70 70 
PP-C 70 70 
EPDM-A 30 30 30 
EPDM-B 30 30 30 
Stabilizer-A 0.05 0.05 0.05 0.05 0.05 0.05 
Stabilizer-B 0.1 0.1 0.1 0.1 0.1 0.1 
Stabilizer-C 0.1 0.1 0.1 0.1 0.1 0.1 
TCE Degreasing .multidot. 
Did Did Did Did Did Did 
Washing Process 
Primer Coating No No No No No No 
Peel Strength of Coated 
1.50 1.45 1.30 1.40 1.10 1.10 
Film 
Izod Impact Strength 
NB NB NB NB NB NB 
______________________________________ 
TABLE 11 
______________________________________ 
Example No. 
37 38 39 40 41 42 
______________________________________ 
PP-A 70 70 
PP-B 70 70 
PP-C 70 70 
EPDM-A 30 30 30 
EPDM-B 30 30 30 
Stabilizer-A 0.05 0.05 0.05 0.05 0.05 0.05 
Stabilizer-B 0.1 0.1 0.1 0.1 0.1 0.1 
Stabilizer-C 0.1 0.1 0.1 0.1 0.1 0.1 
TCE Degreasing .multidot. 
Did Did Did Did Did Did 
Washing Process 
Primer Coating No No No No No No 
Peel Strength of Coated 
1.50 1.40 1.40 1.40 1.35 1.30 
Film 
Izod Impact Strength 
NB NB NB NB NB NB 
______________________________________ 
TABLE 12 
______________________________________ 
Example No. 
43 44 45 46 47 48 
______________________________________ 
PP-A 70 70 70 70 70 70 
EPDM-A 30 30 30 
EPDM-B 30 30 30 
Talc 10 20 30 10 20 30 
Stabilizer-A 0.05 0.05 0.05 0.05 0.05 0.05 
Stabilizer-B 0.10 0.10 0.10 0.10 0.10 0.10 
Stabilizer-C 0.10 0.10 0.10 0.10 0.10 0.10 
TCE Degreasing .multidot. 
Did Did Did Did Did Did 
Washing Process 
Peel Strength of Coated 
1.30 1.25 1.25 1.20 1.15 1.05 
Film: One-pack Type 
Peel Strength of Coated 
1.40 1.35 1.30 1.25 1.20 1.15 
Film: Two-pack Type 
Izod Impact Strength 
NB NB NB NB NB NB 
______________________________________ 
TABLE 13 
______________________________________ 
Example No. 
49 50 51 52 53 54 
______________________________________ 
PP-A 70 70 70 70 70 70 
EPDM-A 30 30 30 
EPDM-B 30 30 30 
Stabilizer-A 0.05 0.05 0.05 0.05 0.05 0.05 
Stabilizer-B 0.10 0.10 0.10 0.10 0.10 0.10 
Stabilizer-C 0.10 0.10 0.10 0.10 0.10 0.10 
Degreasing .multidot. Washing: 
Isopropyl Alcohol 
Did Did 
Surfactant-Containing Did Did 
Phosphoric Acid Aqueous 
Solution 
Benzene Did Did 
Peel Strength of Coated 
0.90 0.90 0.90 0.80 0.80 0.80 
Film: One-pack Type 
Peel Strength of Coated 
1.00 0.95 0.95 0.80 0.80 0.80 
Film: Two-pack Type 
Izod Impact Strength 
NB NB NB NB NB NB 
______________________________________ 
TABLE 14 
______________________________________ 
Comparative Example No. 
22 23 24 
______________________________________ 
PP-A 100 
PP-B 100 
PP-C 100 
Stabilizer-A 0.05 0.05 0.05 
Stabilizer-B 0.10 0.10 0.10 
Stabilizer-C 0.10 0.10 0.10 
TCE Degreasing .multidot. Washing Process 
Did Did Did 
Peel Strength of Coated Film: 
&lt;0.3 &lt;0.3 &lt;0.3 
One-pack Type 
Peel Strength of Coated Film: 
&lt;0.3 &lt;0.3 &lt;0.3 
Two-pack Type 
Izod Impact Strength 
NB NB NB 
______________________________________ 
TABLE 15 
______________________________________ 
Comparative Example No. 
25 26 27 
______________________________________ 
PP-A 100 100 100 
Talc 10 20 30 
Stabilizer-A 0.05 0.05 0.05 
Stabilizer-B 0.10 0.10 0.10 
Stabilizer-C 0.10 0.10 0.10 
TCE Degreasing .multidot. Washing Process 
Did Did Did 
Peel Strength of Coated Film: 
&lt;0.3 &lt;0.3 &lt;0.3 
One-pack Type 
Peel Strength of Coated Film: 
&lt;0.3 &lt;0.3 &lt;0.3 
Two-pack Type 
Izod Impact Strength 
4 3.5 3 
______________________________________ 
TABLE 16 
__________________________________________________________________________ 
Comparative Example No. 
28 29 30 31 32 33 
__________________________________________________________________________ 
PP-A 90 80 70 90 80 70 
EPDM-C 10 20 30 
EPDM-D 10 20 30 
Stabilizer-A 0.05 
0.05 
0.05 
0.05 
0.05 
0.05 
Stabilizer-B 0.10 
0.10 
0.10 
0.10 
0.10 
0.10 
Stabilizer-C 0.10 
0.10 
0.10 
0.10 
0.10 
0.10 
TCE Degreasing .multidot. Washing Process 
Did Did Did Did Did Did 
Primer Coating No No No No No No 
Peel Strength of Coated Film: 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
One-pack Type 
Peel Strength of Coated Film: 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
Two-pack Type 
Izod Impact Strength 
TB TB TB TB TB TB 
__________________________________________________________________________ 
TABLE 17 
__________________________________________________________________________ 
Comparative Example No. 
34 35 36 37 38 39 
__________________________________________________________________________ 
PP-A 90 80 70 90 80 70 
EPDM-C 10 20 30 
EPDM-D 10 20 30 
Stabilizer-A 0.05 
0.05 
0.05 
0.05 
0.05 
0.05 
Stabilizer-B 0.10 
0.10 
0.10 
0.10 
0.10 
0.10 
Stabilizer-C 0.10 
0.10 
0.10 
0.10 
0.10 
0.10 
TCE Degreasing .multidot. Washing Process 
Did Did Did Did Did Did 
Primer Coating No No No No No No 
Peel Strength of Coated Film: 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
One-pack Type 
Peel Strength of Coated Film: 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
&lt;0.3 
Two-pack Type 
Izod Impact Strength 
TB TB TB TB TB TB 
__________________________________________________________________________ 
The polypropylene resin composition according to the present invention 
permits the application of a top coat after a pretreatment such as the 
application of a primer layer or the irradiation with plasma without 
washing with a halogen atom-containing organic solvent or further permits 
the application of a top coat after simply washing with a halogen 
atom-containing organic solvent without subjecting any pretreatment such 
as the application of a primer layer or the irradiation with plasma and 
can provide molded products excellent in bond strength against coated 
films applied thereto and, if necessary, molded products having both 
excellent bond strength and high impact resistance. Therefore, the resin 
composition has enough industrial value.