Resin compositions containing modified polypropylene

A resin composition comprising a modified polypropylene obtained by reacting a polypropylene with a liquid rubber and maleic anhydride in a solvent in the presence of a radical generator, another polyolefin and, if desired, an inorganic and/or an organic filler. The resin composition has excellent coating, adhesion and plating properties.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a resin composition containing a modified 
polypropylene. More particularly, the present invention is concerned with 
a resin composition containing a modified polypropylene obtained by 
reacting a polypropylene with a liquid rubber and maleic anhydride. 
2. Description of the Prior Art 
In general, non-polar plastics such as polyethylene and polypropylene have 
poor dyeability, ink receptivity, plating and coating properties and 
adhesion characteristics owing to the low affinity thereof, although they 
are chemically stable. It is quite difficult to process the non-polar 
plastics to apply a coating printing, etc. 
In order to improve these properties of the plastics, incorporation of 
inorganic fillers in the plastics; physical or chemical treatments of 
plastic articles, e.g., surface treatments such as chemical etching, 
corona discharge treatment, flame treatment, plasma jet treatment, etc.; 
surface-coarsening using sandpaper, etc., and application of primers, 
etc., have heretofore been conducted. 
These techniques, however, the disadvantages in that expensive apparatus 
and complicated operations are needed, the plastic articles to be treated 
are limited in their shapes and sizes, care must be taken in handling the 
already molded plastic articles, and it is difficult to effect a uniform 
treatment. 
On the other hand, a method of introducing polar groups into polypropylene 
resins by reacting them with maleic anhydride, for example, to improve 
their adhesion characteristics and dyeability thereof is described in 
Japanese Patent Publications Nos. 27421/1968 and 15422/1969. This method, 
however, has failed to sufficiently achieve the expected results since it 
is difficult to introduce a large amount of the polar groups. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a resin composition with 
which it is possible to produce an article having excellent adhesion and 
plating characteristics without applying any conventional complicated 
treatment on the surface of the article. 
A further object of the present invention is to provide a resin composition 
with which it is possible to produce an article having excellent ink 
receptivity and coating properties without applying any treatment such as 
a surface-treatment to the article. 
It has now been found that a modified polypropylene can be obtained by 
reacting a polypropylene with a liquid rubber and maleic anhydride in a 
solvent in the presence of a radical generator; that is, a modified 
polypropylene containing an effective amount of polar groups can be 
obtained by reacting a polypropylene with a liquid rubber and maleic 
anhydride. Objects of the present invention are attained by using this 
modified polypropylene as an essential component of the resin 
compositions. 
Thus, the present invention provides a resin composition comprised of at 
least 10 percent by weight of a modified polypropylene containing an 
additional amount of maleic anhydride of from 1 to 10 percent by weight, 
which is produced by the above method, a polyolefin and, if necessary, 
inorganic and/or organic filler. 
DETAILED DESCRIPTION OF THE INVENTION 
A modified polypropylene which is used as an essential component of the 
present invention is produced by reacting a polypropylene with a liquid 
rubber and maleic anhydride in a solvent and in the presence of a radical 
generator. 
There is no limitation to the polypropylene used in producing the modified 
polypropylene. Isotactic polypropylene, atactic polypropylene produced in 
stereoregulated polymerization, and those polypropylenes obtained by 
copolymerizing propylene with a small amount of another olefin are 
generally called polypropylene resins, and can be so used. 
The term "liquid rubber" as herein used designates polymers composed mainly 
of diene monomers and having a number average molecular weight of from 500 
to 10,000. Preferred polymers are those showing fluidity at room 
temperature (about 20.degree. C.). 
Suitable examples of these liquid rubbers include poly-1,2-butadiene, 
poly-1,4-butadiene, polyisoprene, polychloroprene, styrene-butadiene 
copolymers, acrylonitrile-butadiene copolymers, butadiene-isoprene 
copolymers, and butadiene-pentadiene copolymers; such polymers or 
copolymers containing functional groups such as carboxyl, hydroxyl, 
mercapto, halogen, amino, aziridino and epoxy; unsaturated dicarboxylic 
acid half-esters of poly-1,2-butadiene and poly-1,4-butadiene, each being 
hydroxylated at the terminal carbon; heat-decomposed rubber and 
ozone-decomposed rubber; and mixtures thereof. 
The liquid rubber is preferably used in an amount of from 1.0 to 20 parts 
by weight per 100 parts by weight of the polypropylene. When the amount of 
the liquid rubber added is less than 1.0 part by weight, only a minor 
effect is obtained; whereas, in the case of more than 20 parts by weight, 
undesirable gelation of the liquid rubber is predominant. The liquid 
rubber contributes by introducing a large amount of maleic anhydride from 
the standpoint of elementary reaction, and it also acts to improve the 
physical properties such as strength, ink receptivity, adhesion, coating, 
plating, etc., of the modified polypropylene. 
Maleic anhydride is generally used in an amount of from 5 to 50 parts by 
weight per 100 parts by weight of the polypropylene. When the amount of 
the maleic anhydride used is less than 5 parts by weight per 100 parts by 
weight of the polypropylene, the dyeability, adhesion characteristics and 
ink receptivity of articles produced are insufficiently improved; whereas, 
the use of more than 50 parts by weight of the maleic anhydride is 
meaningless as no effect corresponding to the amount is obtained. 
Any radical generator can be used provided that it accelerates the reaction 
of the polypropylene with the liquid rubber and maleic anhydride. Suitable 
examples of these radical generators are benzoyl peroxide, lauroyl 
peroxide, azobisisobutylonitrile, dicumyl peroxide, 
.alpha.,.alpha.'-bis(t-butylperoxydiisopropyl)benzene, 
2,5-dimethyl-2,5-di(ti-butylperoxy)hexane, di-t-butyl peroxide, cumene 
hydroperoxide and t-butyl hydroperoxide. 
A suitable radical generator is selected depending upon the solvent used. 
It is effective to use the radical generator in an amount of from 0.5 to 
10 parts by weight per 100 parts by weight of the polypropylene. The 
addition of more than 10 parts by weight of the radical generator gives no 
greater effect. 
Solvents used in reacting the above polypropylene, liquid rubber, maleic 
anhydride and radical generator can vary, provided that they are able to 
swell or dissolve the polypropylene. For example, hydrocarbons such as 
xylene, toluene, tetralin, decalin, heptane and the like, or halogenated 
hydrocarbons such as monochlorobenzene, dichlorobenzene and the like can 
be used. Among these solvents, a xylene is preferred. The amount of the 
solvent employed can be varied within wide limits provided that the effect 
of the solvent is attained. It is preferred, however, taking into account 
economy and convenience of operation, that the amount is in the range of 
from 500 to 1,000 parts by weight per 100 parts by weight of the 
polypropylene. 
The reaction temperature and time will vary depending upon the kinds of 
radical generator and solvent used, and the concentrations of starting 
materials. The reaction temperature is generally from 50.degree. to 
150.degree. C., and the reaction time is suitably from 2 to 5 hours. The 
most suitable conditions for a reaction system comprising isotactic 
polypropylene, dicumyl peroxide and a xylene are from 120.degree. to 
140.degree. C. and from 3 to 4 hours. 
Isolation of the modified polypropylene obtained can be carried out by 
conventional methods; for instance, the modified polypropylene obtained is 
cooled, precipitated in a poor solvent such as acetone, filtered with 
suction, and dried in a vacuum. 
The amount of maleic anhydride incorporated in the modified polypropylene 
as described above is generally from 1 to 10 percent by weight based on 
the total weight of the modified polypropylene, and under preferred 
conditions is from 3 to 8 percent by weight. When the amount is below 1 
percent by weight, the resin composition exhibits insufficient affinity, 
resulting in low adhesion printing, coating and plating characteristics. 
On the other hand, although it is possible to introduce more than 10 
percent by weight of maleic anhydride by using a liquid rubber in an 
amount of more than 20 parts by weight, no effect corresponding to the 
additional amount is obtained and operations are complicated, which are 
disadvantageous even from the economic standpoint. 
The method of the present invention, in which the reaction is carried out 
in the presence of a liquid rubber, makes it possible to produce a 
modified polypropylene with a larger amount of maleic anhydride 
incorporated therein than in conventional ones. The modified polypropylene 
obtained is more improved in physical properties in comparison with 
conventional polypropylene resins, and furthermore, it has excellent 
dyeability and excellent fabricating characteristics such as adhesion 
characteristics to various kinds of materials, ink receptivity, coating, 
plating, etc. Thus, the modified polypropylene of the present invention 
can be effectively used in producing fiber or plastic molds, particularly 
molds suitable for coating and plating, and furthermore, it can be used 
widely in many industrial applications, e.g., as a blending material for 
modifying other plastics, coating of inorganic materials, etc. 
Next, a resin composition capable of providing articles having improved 
adhesion characteristics is described. 
This resin composition comprises at least 10 percent by weight of a 
modified polypropylene containing 1 to 10 percent by weight of maleic 
anhydride, which is produced by the method described above. This resin 
composition comprises, in general, the modified polypropylene and another 
olefin resin, although it may be composed of the modified polypropylene 
alone. 
Polyolefin resins which can be used in combination with the modified 
polypropylene include polyethylene and polypropylene. Of these polyolefin 
resins, polypropylene is most preferably used. As this polypropylene, 
stereospecific polypropylene, modified stereospecific polypropylene 
prepared by blending with atactic polypropylene and/or low density 
polyethylene, modified stereospecific polypropylene prepared by blending 
with a small amount of another resin, modified polypropylene prepared by 
copolymerizing with a small amount of another olefin and the like can be 
used. Further, a thermoplastic resin such as ABS resin, polystyrene, 
nylon, etc., can also be used. 
The resin composition of the present invention is prepared by mixing or 
compounding the above modified polypropylene and another polyolefin resin, 
if required, followed by sufficient kneading thereof. In this case, the 
modified polypropylene is blended so that its content is at least 10 
percent by weight, preferably at least 20 percent by weight, based upon 
the total weight of the resin composition. In more detail, a resin 
composition of the present invention is prepared by blending from 100 to 
10 percent by weight, preferably 95 to 10 percent by weight and more 
preferably 90 to 20 percent by weight, of the modified polypropylene, and 
from 0 to 90 percent by weight, preferably 5 to 90 percent by weight and 
most preferably 10 to 80 percent by weight of another polyolefin resin 
such as polyethylene, polypropylene, etc. 
Where the content of the modified polypropylene is below 10 percent by 
weight, adhesion, printing, coating and plating characteristics are not 
improved sufficiently, and the object of the present invention is not 
attained. 
The resin composition of the present invention also provides articles 
having excellent adhesion characteristics, ink receptivity, coating and 
plating properties in comparison with related articles obtained from 
conventional polyolefin resins. Thus, it is possible to adhere the new 
articles to metal, various plastics and other materials with ease and 
sufficient strength. For instance, laminated films, laminated (multilayer) 
bottles, etc., produced from the resin compositions of the present 
invention can be utilized suitably as wrapping materials, bottles for 
liquids, etc. In addition, coating of a metal surface with the resin 
composition of the present invention effectively prevents corrosion of the 
metal. 
As described above, the resin composition of the present invention is 
useful for providing articles having excellent ink receptivity, coating, 
plating and adhesion properties. When utilizing the resin composition for 
such uses, a resin composition which is comprised of from 10 to 80 parts 
by weight of a modified polypropylene having a maleic anhydride content of 
from 1 to 10 percent by weight, and from 90 to 20 parts by weight of a 
polyolefin resin is preferable. A resin composition comprising from 30 to 
70 parts by weight of a polyolefin resin and from 70 to 30 parts by weight 
of the modified polypropylene provides superior ink receptivity, coating, 
plating and adhesion properties. When a lower amount of the modified 
polypropylene is present, the resin's affinity to ink or paint is 
insufficient. When a greater amount of the modified polypropylene is 
present, no effect corresponding to the additional amount is obtained, and 
economic disadvantages result. 
Furthermore, incorporation of a filler into the mixture of the polyolefin 
resin and the modified polypropylene increases its characteristics such as 
excellent ink receptivity and coating properties, and provides a resin 
composition having excellent mechanical strength. 
Fillers as blended herein include inorganic and/or organic fillers. These 
fillers increase the strength and suitably coarsen the surface of an 
article, thereby increasing its affinity to paint, i.e., exhibit the 
so-called anchor effect. The above effects can be attained with a small 
amount of coarse filler particles. From this point of view, the amount of 
inorganic filler blended is preferably from 10 to 80 percent by weight 
based upon the total weight of the resin composition and is most suitably 
from 20 to 60 percent by weight. 
On the other hand, with an organic filler the amount blended is preferably 
from 1 to 50 percent by weight and most suitably from 5 to 40 percent by 
weight, based upon the total weight of the resin composition. When the 
filler is added in an excess, kneading and molding become difficult, and 
at the same time, the surface of the article is coarsened excessively, 
resulting in a non-uniform coating surface. 
Preferred examples of inorganic fillers include calcium carbonate, talc, 
clay, silica, kieselguhr, alumina, zinc white, magnesium oxide, mica, 
calcium sulfite, calcium sulfate, calcium silicate, glass powder, glass 
fiber, asbestos and gypsum fiber. Preferred examples of the organic 
fillers include various kinds of wood powders and cellulose fiber. 
Articles produced from the resin compositions of the present invention as 
described above have excellent ink receptivity, coating and plating 
properties, etc., and thus a surface treatment after molding is not 
needed. Moreover, an article produced from the resin composition with a 
filler incorporated therein has superior ink receptivity and mechanical 
strength. Coating materials having particularly excellent affinity to the 
resin composition of the present invention include synthetic coating 
materials such as epoxy resin based-, melamine-alkyd resin based-, 
urethane resin based- and like coating materials, and Japanese lacquer. In 
addition, an oil paint, water paint, cellulose derivative paint and the 
like can be used. 
The resin compositions of the present invention having excellent 
characteristics can be utilized suitably in producing lacquered ware or 
industrial parts, particularly parts of light electrical applicances, 
cars, etc., for which heat-resistance, chemical resistance, etc., are 
required.

The present invention is illustrated in detail with the following typical 
examples and comparative examples. 
EXAMPLE 1 
A mixture of 100 parts by weight of polypropylene containing a copolymer of 
propylene and a small amount of ethylene (melt index: 9 grams/10 min.; 
density: 0.91 g/cm.sup.3), 5 parts by weight of a terminal-hydroxylated 
poly-1,2-butadiene (number average molecular weight: 2000; density: 0.88 
g/cm.sup.3 ; flow point: 17.degree. C.), 20 parts by weight of maleic 
anhydride, 1.72 parts by weight of dicumyl peroxide, and 600 parts by 
weight of xylene were placed in a 1 liter, three-necked separatory flask 
equipped with a stirrer and a reflux apparatus, heated on an oil bath by 
the use of an immersion heater. The mixture was stirred at 120.degree. C. 
for 1 hour, and then at 140.degree. C. for 3 hours. After reaction was 
completed, the reaction mass was cooled and precipitated in a great excess 
of acetone. The precipitate was filtered with suction and further dried at 
70.degree. C. for 50 hours, whereby a white, powdery polymer was obtained. 
The thus-obtained dried product was placed in a Soxhlet extraction 
apparatus and extracted for 16 hours with acetone to thereby remove 
unreacted polybutadiene and maleic anhydride. Thereafter, the maleic 
anhydride content per total weight of the polymer produced was calculated. 
As a result, the acid value was 55.8; that is, the maleic anhydride 
content was 4.9 percent by weight. 
EXAMPLE 2 
The procedure of Example 1 was repeated with the exception that the amount 
of the terminal-hydroxylated poly-1,2-butadiene was increased to 20 parts 
by weight. 
With the polymer so obtained, the acid value was 89.1; that is, the maleic 
anhydride content was 7.8 percent by weight. 
EXAMPLE 3 
The procedure of Example 1 was repeated with the exception that the amount 
of maleic anhydride was increased to 40 parts by weight. 
With the polymer so obtained, the acid value was 67.1; that is, the maleic 
anhydride content was 5.9 percent by weight. 
Comparative Example 1 
The procedure of Example 1 was repeated with the exception that the 
terminal-hydroxylated poly-1,2-butadiene was omitted, and the amount of 
xylene was increased to 800 parts by weight. 
With the polymer so obtained, the acid value was 5.7; that is, the maleic 
anhydride content was 0.5 percent by weight. 
EXAMPLE 4 
The procedure of Example 1 was repeated with the exception that the amount 
of dicumyl peroxide was increased to 3.45 parts by weight. 
With the polymer so obtained, the acid value was 58.7; that is, the maleic 
anhydride content was 5.1 percent by weight. 
Comparative Example 2 
The procedure of Example 4 was repeated with the exception that the 
terminal-hydroxylated poly-1,2-butadiene was omitted, and the amount of 
xylene was increased to 800 parts by weight. 
With the polymer so obtained, the acid value was 4.9; that is, the maleic 
anhydride content was 0.4 percent by weight. 
EXAMPLE 5 
In the same apparatus as used in Example 1, 100 parts by weight of a 
polypropylene containing copolymers of propylene and a small amount of 
ethylene (melt index: 3 grams/10 min.; density: 0.91 g/cm.sup.3), 5 parts 
by weight of a terminal-hydroxylated poly-1,4-butadiene (number average 
molecular weight: 3,000; viscosity: 50 poise (at 30.degree. C.); OH group 
content: 0.83 meq./g.), 20 parts by weight of maleic anhydride, 1.72 parts 
by weight of dicumyl peroxide, and 600 parts by weight of xylene were 
placed, and thereafter the same procedure as used in Example 1 was 
conducted. 
With the polymer so obtained, the acid value was 59.1; that is, the maleic 
anhydride content was 5.2 percent by weight. 
EXAMPLE 6 
In the same apparatus as used in Example 1, 100 parts by weight of a 
propylene homopolymer (melt index: 9 grams/10 min.; density: 0.91 
g/cm.sup.3), 5 parts by weight of a terminal-carboxylated 
poly-1,2-butadiene (number average molecular weight: 2000; density: 0.89 
g/cm.sup.3 ; flow point: 20.degree. C.), 20 parts by weight of maleic 
anhydride, 2.15 parts by weight of 
.alpha.,.alpha.'-bis(t-butylperoxydiisopropyl)benzene, and 600 parts by 
weight of xylene were placed, and thereafter the same procedure as used in 
Example 1 was conducted. 
With the polymer so obtained, the acid value was 53.7; that is, the maleic 
anhydride content was 4.7 percent by weight. 
EXAMPLE 7 
In the same apparatus as used in Example 1, 100 parts by weight of a 
polypropylene containing copolymers of propylene and a small amount of 
ethylene (melt index: 9 grams/10 min.; density: 0.91 g/cm.sup.3), 10 parts 
by weight of a terminal-hydroxylated poly-1,4-butadiene (number average 
molecular weight: 3000; viscosity: 50 poise (at 30.degree. C.); OH group 
content: 0.83 meq./g.), 20 parts by weight of maleic anhydride, 1.72 parts 
by weight of dicumyl peroxide, and 600 parts by weight of xylene were 
placed, heated on an oil bath by the use of an immersion heater, reacted 
with stirring at 120.degree. C. for 1 hour, and further reacted at 
140.degree. C. for 3 hours. After the reaction was completed, the reaction 
mass was cooled and precipitated in a great excess of acetone. The 
precipitate was filtered with suction and further dried at 70.degree. C. 
for 50 hours, whereby a white, powdery polymer was obtained. 
The thus-obtained dried product was placed in a Soxhlet extraction 
apparatus and extracted with acetone for 16 hours to thereby remove the 
unreacted polybutadiene and maleic anhydride. Thereafter, the maleic 
anhydride content per total weight of the polymer produced was calculated. 
As a result, the acid value was 66.2; that is, the maleic anhydride 
content was 5.8 percent by weight. 
The thus-obtained modified polypropylene was fed to a vertical type 
injection molding machine (mold clamping force: 16 tons) and made into a 
plate (3 millimeters thick, 75 millimeters long, 31 millimeters wide) 
under the following molding conditions: cylinder temperature, 200.degree. 
C.; injection pressure, 50 kg/cm.sup.2 ; and mold temperature, room 
temperature. 
Plating on this plate was done with the following process. The plate was 
pretreated to degrease it, and it was immersed for 15 minutes in a 
chemical etching solution (70.degree..+-.5.degree. C.) prepared by adding 
potassium dichromate (15 grams per liter of aqueous solution) to an 
aqueous solution of 60 percent (by volume) of sulfuric acid, 10 percent 
(by volume) of phosphoric acid and 30 percent (by volume) of water. Then, 
the plate was dipped into a solution of tin dichloride at room temperature 
for 5 minutes in order to give induction property, followed by an 
activating treatment by immersing the plate in a solution of palladium 
chloride at room temperature for 2 minutes. 
After chemically applying a nickel plating, the plate was electroplated 
conventionally with a semi-bright nickel plating, bright nickel plating 
and chromium plating in this order. 
Electroplating thickness of the thus-obtained product was less than about 
25.mu.. Evaluation of the plating on the product was done by judgment of 
its appearance visually; the scotch peeling test; bending test and boiling 
test. The boiling test was done by observing the change of the surface of 
the product after applying 4 cycles of treatment of dipping the product 
into boiling water for 2 hours and dipping the product into ice water 
(0.degree. C.) for 20 minutes. The result is shown in Table 1. 
Table 1 
Appearance: satisfactory 
Scotch Peeling*: 100/100 
Bending Test: not peeled 
Boiling Test: unchanged. 
FNT *The test methods used in the examples and comparative examples are as 
follows: a cellophane tape (produced by Nichiban Co., Ltd.) was stuck to a 
coating layer and peeled off rapidly in the 45.degree. direction, which 
was repeated twice. Scotch peeling: the coating layer was scratched with 
the edge of a blade to such an extent that it reached to the surface of 
the underlying article, to produce 100 1 millimeter.times.1 millimeter 
squares thereon. The above tape was stuck on the coating layer and peeled 
off. The mark A of A/100 indicates the number of remaining squares. 
EXAMPLE 8 
The same procedure as used in Example 7 was carried out except that 50 
parts by weight of the modified polypropylene were replaced with 
polypropylene (melt index: 9 grams/10 min.; density: 0.91 g/cm.sup.3). The 
results are shown in Table 2. 
EXAMPLE 9 
The same procedure as used in Example 7 was carried out except that 60 
parts by weight of the modified polypropylene were replaced with 
polypropylene (melt index: 9 grams/10 min.; density: 0.91 g/cm.sup.3). The 
results are shown in Table 2. 
EXAMPLE 10 
The same procedure as described in Example 7 was used with the exception 
that 70 parts by weight of the modified polypropylene were replaced with 
polypropylene (melt index: 9 grams/10 min.; density: 0.91 g/cm.sup.3). The 
results are shown in Table 2. 
EXAMPLE 11 
The same procedure as described in Example 7 was carried out with the 
exception that 80 parts by weight of the modified polypropylene were 
replaced with polypropylene (melt index: 9 grams/10 min.; density; 0.91 
g/cm.sup.3). The results are shown in Table 2. 
Table 2 
______________________________________ 
Appearance of 
Scotch Bending Test 
Boiling 
Example 
Plating Product 
Peeling Bending Test 
Test 
______________________________________ 
8 satisfactory 
100/100 not peeled 
unchanged 
9 " 100/100 " " 
10 " 100/100 " " 
11 " 95/100 peeled " 
______________________________________ 
EXAMPLE 12 
A mixture of 100 parts by weight of polypropylene containing copolymers of 
propylene and a small amount of ethylene (melt index: 9 grams/10 min.; 
density: 0.91 g/cm.sup.3), 5 parts by weight of a terminal-hydroxylated 
poly-1,4-butadiene (number average molecular weight: 3000; viscosity: 50 
poise (at 30.degree. C.); OH group content: 0.83 meq./g), 20 parts by 
weight of maleic anhydride, 1.72 parts by weight of dicumyl peroxide, and 
600 parts by weight of xylene were placed in a 5 liter, three-necked 
separatory flask equipped with a stirrer and a reflux apparatus, heated on 
an oil bath by the use of an immersion heater, reacted with stirring at 
120.degree. C. for 1 hour, and further reacted at 140.degree. C. for 3 
hours. After the reaction was completed, the reaction mass was cooled and 
precipitated in a great excess of acetone. The precipitate was filtered 
with suction and further dried at 70.degree. C. for 50 hours, whereby a 
white, powdery polymer was obtained. 
The thus obtained dried product was placed in a Soxhlet extraction 
apparatus and extracted for 16 hours with acetone to thereby remove 
unreacted polybutadiene and maleic anhydride. Thereafter, the maleic 
anhydride content per total weight of the polymer produced was calculated. 
The maleic anhydride content was 5.8 percent by weight. 
The thus obtained modified polypropylene, in an amount of 50 parts by 
weight, was mixed with 50 parts by weight of polypropylene (melt index: 9 
grams/10 min.; density: 0.91 g/cm.sup.3), and the resulting mixture was 
kneaded in a 40 millimeter extruder. A film of an average thickness of 
80.mu. was produced by means of a compression molding machine. 
On the other hand, a 150.mu. thick aluminum plate was degreased by dipping 
in acetone for several days and dried at room temperature. 
The thus obtained film (A) and aluminum plates (B) were laid one upon 
another in the order of B-A-B to produce a three-layer laminate. This 
laminate was heated and pressed at an adhesion temperature of 200.degree. 
C. and pressure of 100 kg/cm.sup.2 for about 5 minutes, and then cooled to 
produce a composite plate. 
With this composite plate, T-peeling strength was 19.6 kg/2.5 cm. The 
T-peeling test was conducted according to ASTM-D1876-72. 
For comparison, T-peeling strength was determined with the plates produced 
from the non-modified polypropylene and from the modified polypropylene. 
As a result, the former was 0 kg/2.5 cm. and the latter was 9.0 kg/2.5 
cm., respectively. 
EXAMPLE 13 
The procedure of Example 12 was repeated with the exception that the amount 
of the terminal-hydroxylated poly-1,4-butadiene was increased to 10 parts 
by weight, whereby a modified polypropylene having a maleic anhydride 
content of 6.9 percent by weight was obtained. 
The thus obtained modified polypropylene in an amount of 40 parts by weight 
was mixed with 60 parts by weight of the same polypropylene as used in 
Example 12, and thereafter the same procedure as used in Example 12 was 
conducted to produce a composite plate of the modified polypropylene and 
aluminum plates. 
With the thus obtained composite plate, T-peeling strength was 9.3 kg/2.5 
cm. 
Comparative Example 3 
From the same polypropylene as used in Example 12 a 80.mu. thick film was 
produced. A composite plate of the film and aluminum plates was produced 
according to the same method as used in Example 12. 
With the thus obtained composite plate, T-peeling strength was 0 kg/2.5 cm. 
Comparative Example 4 
The procedure of Example 12 was repeated with the exception that the 
terminal-hydroxylated poly-1,4-butadiene was omitted, whereby a modified 
polypropylene having a maleic anhydride content of 0.5 percent by weight 
was obtained. 
This modified polypropylene in an amount of 50 parts by weight was mixed 
with 50 parts by weight of the same polypropylene as used in Example 12. 
Thereafter, the same method as used in Example 12 was repeated to produce 
a composite plate of the film produced from the above mixture and aluminum 
plates. 
With the thus obtained composite plate, T-peeling strength was 1.3 kg/2.5 
cm. 
Comparative Example 5 
The modified polypropylene obtained in Example 12, in an amount of 5 parts 
by weight, was mixed with 95 parts by weight of the same polypropylene as 
used in Example 12. Thereafter the same method as used in Example 12 was 
repeated to produce a composite plate of the film produced from the above 
mixture and aluminum plates. 
With the thus obtained composite plate, T-peeling strength was 1.0 kg/2.5 
cm. 
EXAMPLE 14 
The procedure of Example 12 was repeated with the exception that propylene 
homopolymer (melt index: 8 grams/10 min.; density: 0.91 g/cm.sup.3) was 
used in place of the polypropylene containing copolymers of propylene and 
ethylene, whereby a modified polypropylene having a maleic anhydride 
content of 6.3 percent by weight was obtained. 
The modified polypropylene so obtained, in an amount of 50 parts by weight, 
was mixed with 50 parts by weight of the same polypropylene as used in 
Example 12. Thereafter the same method as used in Example 12 was conducted 
to produce a composite plate of the film produced from the above mixture 
and aluminum plates. 
With the thus obtained composite plate, T-peeling strength was 8.5 kg/2.5 
cm. 
EXAMPLE 15 
The procedure of Example 12 was repeated with the exception that a 
terminal-carboxylated poly-1,2-butadiene (number average molecular weight: 
2000; density: 0.89 g/cm.sup.3 ; flow point: 20.degree. C.) was used in 
place of the terminal-hydroxylated poly-1,4-butadiene, whereby a modified 
polypropylene having a maleic anhydride content of 6.3 percent by weight 
was obtained. 
The modified polypropylene so obtained, in an amount of 50 parts by weight, 
was mixed with 50 parts by weight of the same polypropylene as used in 
Example 12. Thereafter the same method as used in Example 12 was conducted 
to produce a composite plate of a film produced from the above mixture and 
aluminum plates. 
With the thus obtained composite plate, T-peeling strength was 18.4 kg/2.5 
cm. 
EXAMPLE 16 
The modified polypropylene obtained in Example 12, in an amount of 30 
parts by weight, was mixed with 70 parts by weight of polyethylene (melt 
index: 6.0 grams/10 min.; density: 0.970 g/cm.sup.3). Thereafter the same 
method as used in Example 12 was conducted to produce a composite plate of 
a film produced from the above mixture and aluminum plates. 
With the thus obtained composite plate, T-peeling strength was 8.2 kg/2.5 
cm. 
EXAMPLE 17 
A mixture of 100 parts by weight of polypropylene containing copolymers of 
propylene and a small amount of ethylene (melt index: 9 grams/10 min.; 
density: 0.91 g/cm.sup.3), 5 parts by weight of a terminal-hydroxylated 
poly-1,4-butadiene (number average molecular weight: 3000; viscosity: 50 
poise (at 30.degree. C.), OH group content: 0.83 meq./g.), 20 parts by 
weight of maleic anhydride, 1.72 parts by weight of dicumyl peroxide, and 
600 parts by weight of xylene were placed in a 5 liter, three-necked 
separatory flask equipped with a stirrer and a reflux apparatus, heated on 
an oil bath by the use of an immersion heater, reacted with stirring at 
120.degree. C. for 1 hour, and further reacted at 140.degree. C. for 3 
hours. After the reaction was completed, the reaction mass was cooled and 
precipitated in a great excess of acetone. The precipitate was filtered 
with suction and further dried at 70.degree. C. for 50 hours, whereby a 
white, powdery polymer was obtained. 
The thus obtained dried product was placed in a Soxhlet extraction 
apparatus and extracted for 16 hours with acetone to thereby remove 
unreacted polybutadiene and maleic anhydride. Thereafter, the maleic 
anhydride content per the total weight of the polymer produced was 
calculated. The maleic anhydride content was 5.8 percent by weight. 
The modified polypropylene above obtained, in an amount of 40 parts by 
weight, was mixed with 60 parts by weight of polypropylene (melt index: 9 
grams/10 min.; density: 0.91 g/cm.sup.3. The same polypropylene was also 
used in Examples 18, 20, 21, 22, 23 and 24). The resulting mixture was 
kneaded, and then compression-molded into a plate of 1.5 millimeters 
thickness. 
With this plate, coating tests were conducted. The results obtained are 
shown in Table 3. 
EXAMPLE 18 
The same procedure as described in Example 17 was repeated with the 
exception that the amount of the terminal-hydroxylated poly-1,4-butadiene 
was reduced to 3 parts by weight, and the amount of maleic anhydride was 
reduced 20 parts by weight to 10 parts by weight, whereby a modified 
polypropylene having a maleic anhydride content of 3.0 percent was 
obtained. 
The thus obtained modified polypropylene, in an amount of 40 parts by 
weight, was mixed with 60 parts by weight of the same polypropylene as 
used in Example 17. Then the same coating tests as used in Example 17 were 
carried out. The results are shown in Table 3. 
Comparative Example 6 
A plate of 1.5 millimeters thickness was obtained from polypropylene alone. 
With this plate, coating tests were conducted. The results are shown in 
Table 3. 
Comparative Example 7 
The same procedure as Example 17 was repeated with the exception that the 
terminal-hydroxylated poly-1,4-butadiene was omitted, whereby a modified 
polypropylene having a maleic anhydride content of 0.5 percent by weight 
was obtained. 
This modified polypropylene, in an amount of 40 parts by weight, was 
blended with 60 parts by weight of the same polypropylene as used in 
Example 17. Then, the same coating tests as described in Example 17 were 
made. The results are shown in Table 3. 
Comparative Example 8 
Ten parts by weight of the modified polypropylene obtained in Example 17 
were mixed with 90 parts by weight of polypropylene used in Example 17. 
Then, the same coating tests as described in Example 17 were made. The 
results are shown in Table 3. 
EXAMPLE 19 
Fifty parts by weight of the modified polyproyplene produced in Example 17 
were mixed with 50 parts by weight of polyethylene (melt index: 6.0 
grams/10 min.; density: 0.97 g/cm.sup.3). Then, the same coating tests as 
described in Example 17 were made. The results are shown in Table 3. 
EXAMPLE 20 
The procedure of Example 17 was repeated with the exception that a 
propylene homopolymer (melt index: 8 grams/10 min.; density: 0.91 
g/cm.sup.3) was used in place of a polypropylene containing copolymers of 
propylene and ethylene (melt index: 9 grams/10 min.; density: 0.91 
g/cm.sup.3), whereby a modified polypropylene having a maleic anhydride 
content of 6.3 percent by weight was obtained. 
The modified polypropylene so obtained, in an amount of 40 parts by weight, 
was blended with 60 parts by weight of polypropylene (melt index: 9 
grams/10 min.; density: 0.91 g/cm.sup.3). Then, the same coating tests as 
described in Example 17 were carried out. The results are shown in Table 
3. 
EXAMPLE 21 
The procedure of Example 17 was repeated with the exception that a mixture 
of polypropylene (80 parts by weight) and low density polyethylene (melt 
index: 8 grams/10 min.; density: 0.924 g/cm.sup.3) (20 parts by weight) 
was used in place of polypropylene, whereby a modified polypropylene 
having a maleic anhydride content of 5.8 percent by weight was obtained. 
The modified polypropylene thus obtained, in an amount of 40 parts by 
weight, was mixed with 60 parts by weight of polypropylene. Then, the same 
coating tests as described in Example 17 were made. The results are shown 
in Table 3. 
EXAMPLE 22 
The procedure of Example 17 was repeated with the exception that a 
terminal-carboxylated poly-1,2-butadiene (number average molecular weight: 
2000; density: 0.89 g/cm.sup.3 ; flow point: 20.degree. C.) was used 
instead of a terminal-hydroxylated poly-1,4-butadiene, whereby a modified 
polypropylene having a maleic anhydride content of 6.3 percent by weight 
was obtained. 
The modified polypropylene, in an amount of 40 parts by weight, was mixed 
with 60 parts by weight of polypropylene of Example 17. Then, the same 
coating tests as described in Example 17 were carried out. The results are 
shown in Table 3. 
Table 3 
______________________________________ 
Whole Peeling Test *4 Scotch Peeling 
*1 *2 *3 Test *4 
Example Uni-ace 100 
IR Cashew Mela 200 
IR Cashew 
______________________________________ 
17 o o o 100/100 
18 o o o 100/100 
6* x x x 0/100 
7* x x x 0/100 
8* x x x 0/100 
19 o o o 100/100 
20 o o o 100/100 
21 o o o 100/100 
22 o o o 100/100 
______________________________________ 
*Comparative Example 
*1 Urethane resin paint produced by Cashew Co., Ltd. 
*2 Epoxy resin paint produced by Cashew Co, Ltd. 
*3 Melaminealkyd resin paint produced by Cashew Co, Ltd. 
*4 The test methods used in the examples and comparative examples are as 
follows: a cellophane tape (produced by Nichiban Co., Ltd.) was stuck to 
coating layer and peeled off rapidly in the 45.degree. direction, which 
was repeated twice. 
Whole peeling: the above tape was stuck on a coating layer and peeled off 
The mark o indicates that no peeling resulted. The mark x indicates that 
the entire coating layer peeled off. 
Scotch peeling: the coating layer was scratched with the edge of a blade 
to such an extent that it reached to the surface of the underlying 
article, to produce 100 1 millimeter .times. 1 millimeter squares thereon 
The above tape was stuck on the coating layer and peeled off. The mark A 
of A/100 indicates the number of remaining squares. 
EXAMPLE 23 
The modified polypropylene obtained in Example 17, in an amount of 30 parts 
by weight, and 70 parts by weight of polypropylene were kneaded in a 
laboplasto mill, and then compression-molded into a 1.5 millimeter thick 
plate. 
With this plate, various tests were conducted. The results obtained are 
shown in Table 4. 
EXAMPLE 24 
The modified polypropylene obtained in Example 17, in an amount of 30 parts 
by weight, 70 parts by weight of polypropylene, and 80 parts by weight of 
talc (average particle size: 6.5.mu.) were kneaded in a laboplasto mill, 
and then compression-molded into a 1.5 millimeter thick plate. Test 
results with this place are shown in Table 4. 
Comparative Example 9 
The modified polypropylene obtained in Comparative Example 7 (maleic 
anhydride content: 0.5 percent by weight), in an amount of 30 parts by 
weight, was used. In the same manner as in Example 24, a plate was 
produced. Test results with this plate are shown in Table 4. 
EXAMPLE 25 
As a filler, 80 parts by weight of calcium sulfite were used, and in the 
same manner as in Example 24, a plate was produced. Test results with this 
plate are shown in Table 4. 
EXAMPLE 26 
As a filler, 30 parts by weight of 120 to 150 mesh powdery wood were used, 
and in the same manner as in Example 24, a plate was produced. Test 
results with this plate are shown in Table 4. 
EXAMPLE 27 
As fillers, 10 parts by weight of 150 to 200 mesh powdery wood and 50 parts 
by weight of heavy-duty calcium carbonate (average particle size: 1.8.mu.) 
were used, and in the same manner as in Example 24, a plate was produced. 
Test results with this plate are shown in Table 4. 
Comparative Example 10 
The modified polypropylene obtained in Example 17, in an amount of 10 parts 
by weight, 90 parts by weight of polypropylene (melt index: 9 grams/10 
min.; density: 0.91 g/cm.sup.3), and 30 parts by weight of 120 to 150 mesh 
of powdery wood were used. In the same manner as in Example 24, a plate 
was produced. Test results with this plate are shown in Table 4. 
Table 4 
______________________________________ 
Strength Test 
Coating Test *1 
Tensile Bending 
Whole Scotch Strength Strength 
Peeling 
Peeling (kg/cm.sup.2) 
(kg/cm.sup.2) 
______________________________________ 
Example 23 
o 100/100 305 338 
Example 24 
o 100/100 343 472 
Comparative 
Example 9 x 0/100 281 412 
Example 25 
o 100/100 342 480 
Example 26 
o 100/100 308 402 
Example 27 
o 100/100 324 450 
Comparative 
Example 10 
x 0/100 270 381 
______________________________________ 
*1: IR Cashew was used.