Molded articles of thermoplastic elastomer

Molded articles of thermoplastic elastomer obtained in accordance with the present invention comprise a molded product prepared from a thermoplastic elastomer containing a partially cross-linked product of ethylene/.alpha.-olefin copolymer rubber and a polyolefin resin, a primer layer containing at least one compound selected from the group of saturated polyesters and chlorinated polyolefins and formed on the surface of said molded article, and a topcoat layer containing at least one compound selected from the group of saturated polyesters, acrylic ester resins, polyvinyl chloride and polyisocyanate (provided that the topcoat layer contains at least the acrylic ester resin when the primer layer consists only of the saturated polyester) and formed on said primer layer. The molded articles of the invention mentioned above have such excellent surface characteristics that the surface thereof is hard to get a scratch, excellent in appearance as well as in touch and, moreover, is hard to subject to attack by hydrocarbon solvents.

FIELD OF THE INVENTION 
This invention relates to molded article of thermoplastic elastomer used as 
interior automotive sheets or the like, and more particularly to molded 
articles of thermoplastic elastomer having excellent surface 
characteristics. 
BACKGROUND OF THE INVENTION 
Heretofore, non-rigid polyvinyl chloride or polyblends comprising non-rigid 
polyvinyl chloride and ABS resins have been mainly used for the 
preparation of interior automotive sheets for use as outer skins of 
instrument panel pads or door trim. In the use of this non-rigid polyvinyl 
chloride for the purpose intended, however, there were involved such 
problems that because of large amounts of plasticizers present in the 
non-rigid polyvinyl chloride, a window glass of automobile tarnishes owing 
to volatilization of the plasticizers, the interior automotive sheets are 
deteriorated and discolored by ultraviolet light of sunlight incident 
through automotive windows or by thermal decomposition. Particularly, a 
further serious problem was that the non-rigid polyvinyl chloride 
sometimes undergoes brittle fracture in a cold district. 
In recent years, owing to such circumstances, interior sheets prepared from 
polyolefin resins such as polypropylene have come to be used. However, 
molded articles, such as interior sheets comprising polyolefin resins had 
such problems that the molded articles are liable to receive scratches on 
the surface thereof, poor in external appearance because of excessively 
high surface gloss as well as in touch because of surface roughness and, 
moreover, the surface of said molded articles are apt to be attacked by 
hydrocarbon solvents. 
In order to solve such problems as mentioned above, there have been made 
various attempts, for instance, Japanese Patent Laid-Open-to-Public Publn. 
No. 197741/1985 proposes a process for preparing sheets for use in 
interior automotive decoration, characterized in that the sheet is formed 
from a thermoplastic elastomer comprising a polyolefin resin and a 
partially cross-linked type ethylene/.alpha.-olefin copolymer rubber, and 
on the surface of the thus formed sheet is coated a reactive paint 
containing a saturated polyester resin, acrylic ester resin or an 
isocyanate resin. 
The sheet prepared by the process disclosed in this Japanese Patent L-O-P 
Publn. No. 197741/1985 cannot be said to have sufficiently excellent 
surface characteristics, though such surface characteristics as surface 
abrasion resistance has been improved in comparison with the sheet 
obtained by said process but omitting the reactive paint coating step, and 
hus a further improvement in surface characteristics has been desired 
therefor. 
The present inventors conducted extensive research with the view of 
obtaining molded articles of thermoplastic elastomer, such as interior 
automotive leather-like sheets excellent in surface characteristics, and 
eventually found that molded articles having excellent surface 
characteristics are obtained by coating a primer having a specific 
composition on the surface of molded articles prepared from thermoplastic 
elastomers to form a primer layer thereon, and then applying the aforesaid 
reactive paint onto the surface of the thus formed primer layer. 
OBJECT OF THE INVENTION 
The present invention is intended to solve such problems associated with 
the prior art as mentioned above, and its object is to provide molded 
articles prepared from thermoplastic elastomers for use as interior 
automotive sheets or the like, the surface of which is hard to get 
scratches and excellent in external appearance as well as in touch and, 
moreover, is hard to subject to an attack by hydrocarbon solvents. 
SUMMARY OF THE INVENTION 
The molded articles prepared from thermoplastic elastomers in accordance 
with the present invention are characterized by having a primer layer 
containing at least one compound selected from among saturated polyesters 
and chlorinated polyolefins, said primer layer being coated on the surface 
of a molded article prepared from a thermoplastic elastomer containing a 
partially cross-linked product of an ethylene/.alpha.-olefin copolymer 
rubber and, if necessary, a polyolefin resin, and on the primer layer a 
topcoat layer containing at least one compound selected from among 
saturated polyesters, acrylic ester resins, polyvinyl chloride and 
polyisocyanate (provided that said topcoat layer contains at least an 
acrylic ester resin when said primer layer consists only of a saturated 
polyester). 
The thermoplastic elastomer molded articles of the present invention have 
such excellent surface characteristics that the surface thereof is hard to 
get scratches, excellent in external appearance as well as in touch and, 
moreover, is hard to subject to an attack by hydrocarbon solvent since 
they have on the surface of a molded article prepared from a thermoplastic 
estomer containing a partially cross-linked product of an 
ethylene/.alpha.-olefin copolymer rubber and, if necessary, a polyolefin 
resin, a primer layer having a specific composition and a topcoat layer 
having a specific composition in that order. 
DETAILED DESCRIPTION OF THE INVENTION 
The molded articles of thermoplastic elastomer of the present invention, 
which are used as interior automotive sheets or the like, are illustrated 
below in detail. 
The thermoplastic elastomers used in the present invention contain as an 
essential component a partially cross-linked product of an 
ethylene/.alpha.-olefin copolymer rubber and, if necessary, a polyolefin 
resin. Representatives of such thermoplastic elastomers are preferably 
those which are formed from a composition comprising; 
100-30 parts by weight of a partially cross-linked copolymer rubber 
composition (I) obtained by dynamically heat treating in the presence of a 
crosslinker a mixture comprising 
(a) 100-20 parts by weight of an ethylene/.alpha.-olefin copolymer rubber, 
(b) 0-80 parts by weight of a polyolefin resin (herein the amount of 
(a)+(b) is selected so as to become 100 parts by weight), 
and if necessary 
0-200 parts by weight (preferably 0-100 parts by weight) of at least one 
component selected from the group of 
(c) peroxide non-crosslinking type hydrocarbon rubbery substances and 
(d) mineral oil type softening agents, and 
0-70 parts by weight of a polyolefin resin (II). 
The above-mentioned thermoplastic elastomers used in the present invention 
may further be exemplified concretely with reference to the following 
compositions. 
(1) A thermoplastic elastomer composition, i.e. a partially cross-linked 
copolymer rubber composition (I) obtained by dynamically heat treating in 
the presence of a crosslinker a mixture (I) comprising; 
(a) 100-20, preferably 90-20 parts by weight of an ethylene/.alpha.-olefin 
copolymer rubber, and 
(b) 0-80, preferably 10-80 parts by weight of a polyolefin resin, or 
a mixture (II) comprising; 
a blend of 100 parts by weight of the mixture (I) and 0-200, preferably 
3-100 more preferably 5-100 parts by weight of 
(c) a peroxide non-crosslinking type hydrocarbon rubbery substance and/or 
(d) a mineral oil type softening agent. 
(2) A thermoplastic elastomer composition comprising a mixture containing 
100 parts by weight of a thermoplastic elastomer composition comprising 
the above-mentioned partially cross-linked copolymer rubber (I) and up to 
700/3 parts by weight (about 233 parts by weight), based on the copolymer 
rubber (I), of a polyolefin resin (II). 
In the present invention, there may also be used as the thermoplastic 
elastomer the following thermoplastic elastomer composition. 
(3) A thermoplastic elastomer composition comprising a mixture containing; 
100-20, preferably 90-20 parts by weight of a partially cross-linked 
product of an ethylene/.alpha.-olefin copolymer rubber (I) obtained by 
statically heat treating, for example, heat treatment of the rubber 
mixture by pressing, in the presence of a crosslinker, (a) an 
ethylene/.alpha.-olefin copolymer rubber or a mixture of 100 parts by 
weight of said copolymer rubber (a) and up to 200, preferably 200 parts by 
weight, based on the copolymer rubber, of (c) a peroxide non-crosslinking 
type rubbery substance and/or (d) a mineral oil type softening agent, and 
10-80 parts by weight of a polyolefin resin (II). 
Of the above-exemplified thermoplastic elastomer compositions (1)-(3), 
preferably used are the thermoplastic elastomers shown in (1) and (2) 
above. 
In the present invention, it is not preferable to use uncrosslinked 
elastomer compositions in place of partially cross-linked thermoplastic 
elastomer compositions because the polymer compositions obtained thereby 
decrease in tensile characteristics, heat resistance or oil resistance. 
The ethylene/.alpha.-olefin copolymer rubber (a) which is a starting 
material for the thermoplastic elastomer used in the present invention 
includes substantially amorphous copolymer rubbers comprising mainly 
ethylene and .alpha.-olefin of 3-14 carbon atoms, for example, 
ethylene/propylene copolymer rubber, ethylene/propylene/non-conjugated 
diene terpolymer or multi-component copolymer rubber, ethylene/butadiene 
copolymer rubber, ethylene-1-butene copolymer rubber, and 
ethylene/1-butene/non-conjugated diene multi-component copolymer rubber, 
or mixtures thereof. Of these copolymer rubbers, preferred are 
ethylene/propylene copolymer rubber and ethylene/propylene/non-conjugated 
diene terpolymer. 
The non-conjugated diene referred to in the above-mentioned copolymer 
rubbers signifies dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, 
methylenenorbornene, 5-ethylidene-2-norbornene, etc., and copolymers 
containing as a third component dicyclopentadiene or 
5-ethylidene-2-norbornene are preferred. 
These copolymers or multi-component polymers have Mooney viscosity 
[ML.sub.1+4 (100.degree. C.)] of 10-180, preferably 40-140, and an iodine 
value (unsaturation degree) of preferably less than 16. 
As the amount of each constituent unit contained in these copolymer rubbers 
at the 1-olefin moiety, a proportion of ethylene unit/.alpha.-olefin unit 
is 50/50 to 92/8, preferably 70/30 to 85/15 (molar ratio), and a 
proportion of 1-olefin (ethylene+.alpha.-olefin) unit/non-conjugated diene 
unit is usually 100/0-90/10, preferably 98/2 to 90/10, more preferably 
97/3 to 94/6. 
The polyolefin resin (b) to be mixed with the ethylene/.alpha.-olefin 
copolymer rubber at the time of dynamic heat treatment includes resinous 
high molecular substances, for example, homopolymers of 1-olefin such as 
ethylene, propylene, butene-1, hexene-1, 4-methyl-1-pentene, etc., 
copolymers of these monomers, or copolymers of .alpha.-olefin and less 
than 15 mol % of other polymeric monomers, for example, ethylene/vinyl 
acetate copolymers, ethylene/acrylic acid copolymer, ethylene/methyl 
acrylate copolymers, ethylene/ethyl acrylate copolymers, 
ethylene/methacrylic acid copolymers, ethylene/methyl methacrylate 
copolymers, etc. Of these polyolefin resins, preferably used are those 
having a melt index (ASTM-D-1238-c65T) of 0.1-50 g/10 min, particularly 
5-20 g/10 min and a crystallinity index of 40% or higer as obtained by 
X-ray diffractometry. 
Of the above-illustrated polyolefin resins (b), those which may be 
exemplified as the preferred polyolefin resin (b) are peroxide 
decomposition type polyolefin resins (polyolefin resins which decrease in 
molecular weight and increase in flowability of resin by thermal 
decomposition when mixed with a peroxide followed by kneading under 
application of heat) having a melt index of 0.1-50 g/10 min and a 
crystallinity index of 40% or higher. The peroxide decomposition type 
polyolefin resins exemplified above include isotactic polypropylene or 
copolymers of propylene and less than 15 mol % of other .alpha.-olefins, 
for example, propylene/ethylene copolymers, propylene/1-butene copolymers, 
propylene/1-hexene copolymers and propylene/4-methyl-1-pentene copolymers. 
Where sheet-like molded articles are intended, use is preferably made of a 
mixture of the above-mentioned peroxide decomposition type polyolefin 
resin and a peroxide crosslinking type polyolefin resin (a polyolefin 
resin which decreases in flowability of resin by crosslinking when mixed 
with a peroxide followed by kneading under application of heat), for 
example, a low, medium or high density polyethylene having a density of 
0.910 to 0.940, in a proportion by weight of 100/0 to 30/70, particularly 
40/20 to 20/40, because of excellent film forming properties of the 
mixture. The thermoplastic elastomer compositions comprising a mixture of 
(a) 30-50 parts by weight of an ethylene/.alpha.-olefin copolymer, (b) 
20-40 parts by weight of a polypropylene resin and 20-40 parts by weight 
of a polyethylene resin and, if necessary, (c) a peroxide non-crosslinking 
type hydrocarbon rubbery substance and/or (d) a mineral oil, said mixture 
having been dynamically crosslinked, are particularly preferred since the 
sheet-like articles obtained therefrom are excellent in physical 
properties. 
The peroxide non-crosslinking type hydrocarbon rubbery substance (c) which 
is an optional component used at the time of preparation of the 
thermoplastic elastomer signifies a hydrocarbon type rubbery substance 
which does not crosslink even when mixed with a peroxide and kneaded under 
application of heat and does not decrease in flowability, for example, 
polyisobutylene rubber, butyl rubber, propylene/ethylene copolymer rubber 
containing at least 70 mol % of propylene, propylene/1-butene copolymer 
rubber or atactic polypropylene. Among these, most preferred are 
polyisobutylene rubber, butyl rubber and propylene/1-butene copolymer 
rubber. 
The mineral oil type softening agent (d) is a high boiling petroleum 
fraction which is used for weakening the intramolecular forces of rubber 
when rubber is roll processed, thereby facilitating the processing of 
rubber and, at the same time, promoting dispersion of carbon black or 
white carbon in the rubber, reducing hardness of vulcanized rubber, or 
increasing flexibility or elasticity. The high boiling petroleum fractions 
of the paraffin, naphthene or aromatic type may be used. 
In preparing the thermoplastic elastomers, the incorporation of such 
peroxide non-crosslinking type hydrocarbon rubbery substance (c) and/or 
mineral oil type softening agent (d) is not always necessary. However, in 
order to further improve flow characteristics, i.e. mold processing 
characteristics, of polymer compositions, it is desirable to add up to 
200, preferably 3-100 parts by weight of the above-mentioned (c) and/or 
(d) to 100 parts by weight of the sum of an ethylene/.alpha.-olefin 
copolymer rubber (a) and a polyolefin resin (b). 
The polyolefin resin (II) which is added, if necessary, after the dynamic 
heat treatment in accordance with the present invention includes resins 
similar to the polyolefin resin (b) added at the time of the dynamic heat 
treatment, that is, said polyolefin resin (II) includes homopolymers of 
1-olefin such as ethylene, propylene, butene-1, hexene-1, 
4-methyl-1-pentene, etc., copolymers of two or more of these monomers, or 
copolymers of .alpha.-olefin and less than 15 mol % of other polymeric 
monomers, for example, ethylene/vinyl acetate copolymers, ethylene/acrylic 
acid copolymers, ethylene/methyl acrylate copolymers, ethylene/ethyl 
acrylate copolymers, ethylene/methacrylic acid copolymers, ethylene/methyl 
methacrylate copolymers, etc. These polyolefin resins (II) preferably have 
a melt index (ASTM-D-1238-65T, 190.degree. C. but 230.degree. C. in case 
of propylene polymers) of 5-100, particularly 10-50. Where the polyolefin 
resins are added at the time of the dynamic heat treatment and also after 
said heat treatment, the polyolefin resin (b) and polyolefin resin (II) 
may be the same or different. 
To prepare a partially cross-linked product of the ethylene/.alpha.-olefin 
copolymer rubber, which is one component of the thermoplastic elastomer 
used in the present invention, it is sufficient that 100 parts by weight 
of a blend comprising a mixture of 100-20 parts by weight of an 
ethylene/.alpha.-olefin copolymer rubber, 0-80 parts by weight of a 
polyolefin resin (b) and, if necessary, 0-200 parts by weight of a 
peroxide non-crosslinking type rubber (c) and/or a mineral oil type 
softening agents (d), is mixed with about 0.01-3%, preferably 0.05-3% more 
preferably 0.1-0.5% by weight, based on the blend, of a crosslinker and 
that the mixture dynamically heat treated to effect partial crosslinking. 
By dynamic heat treatment as used herein is meant the fact that the 
kneading is effected in a molten state. 
The kneading is preferably effected in a closed type apparatus and in an 
inert gas atmosphere such as nitrogen or carbon dioxide gas. The kneading 
temperature is usually 150.degree.-280.degree. C., preferably 
170.degree.-240.degree. C., and the kneading time is usually 1-20 minutes, 
preferably 1-10 minutes. 
Crosslinkers used for the intended partial crosslinking are organic 
peroxides, sulfur, phenol type vulcanizing agents, oximes, polyamine, etc. 
Of these crosslinkers, organic peroxides and phenol type vulcanizing 
agents are preferred from the standpoint of physical properties of the 
thermoplastic elastomers obtained. 
Usable as the phenol type vulcanizing agents are alkylphenolformaldehyde 
resins, triazine-formaldehyde resins and melamine-formaldehyde resins. 
Usable as the organic peroxides are dicumyl peroxide, 
di-tert-butylperoxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 
2,5-dimethyl-2,5-bis(tert-butylperoxy)hexine-3, 
1,3-bis(tert-butylperoxyisopropyl)benzene, 
1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 
n-butyl-4,4-bis(tert-butylperoxy)valerate, dibenzoylperoxide, 
tert-butylperoxybenzoate, etc. Of these organic peroxides, bisperoxide 
type compounds are preferred in point of less odor and high scorch 
stability, and particularly optimal is 
1,3-bis(tert-butylperoxyisopropyl)benzene. 
At the time of effecting partial crosslinking heat treatment, the blending 
of such crosslinking aids such as p-quinonedioxime, 
p,p'-dibenzoylquinonedioxime, etc., of polyfunctional vinyl monomers such 
as divinylbenzene (DVB), diethylene glycol methacrylate, polyethylene 
diglycol methacrylate, etc. is preferable since a more uniform and mild 
crosslinking reaction can be realized. Particularly, the blending of 
divinylbenzene (DVB) is most preferred since the crosslinking effect 
obtained by the heat treatment is uniform, and thermoplastic elastomers 
well balanced between flowability and physical properties are obtained 
thereby. 
The thermoplastic elastomers may further have incorporated therein fillers 
such as carbon black, clay, talc, calcium carbonate, calcium bicarbonate, 
kaolin, diatomaceous earth, silica, alumina, asbestos, graphite, glass 
fiber, etc. or antioxidants such as phenyl-.alpha.-naphthylamine, 
2,6-ditertiary-butylphenol, 
tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], etc., 
weathering agents, flame retardants, antistatic agents and the like 
additives. 
These fillers and additives may be added to the thermoplastic elastomers at 
the stage of preparation thereof or at the time of molding the prepared 
thermoplastic elastomers. 
By partial crosslinking as used herein is meant that the composition after 
being crosslinked has been found to be crosslinked to such an extent that 
the crosslinked composition does not lose its properties as a 
thermoplastic elastomer, and usually is meant a composition having a gel 
content of at least 40% as measured by the following procedure. Of the 
crosslinked compositions, preferred are those having the gel content of at 
least 45%, particularly 70-99.5%. 
The measurement of gel content is conducted in the following manner. About 
100 mg of sample pellets of thermoplastic elastomer is weighed, and the 
sample pellets are placed in a closed container and immersed at 23.degree. 
C. for 48 hours in 30 cc of cyclohexane, and thereafter the sample pellets 
are taken out therefrom and dried for at least 72 hours until no change in 
in weight is observed. From the weight of this dried residue is deducted a 
total weight of all the additives such as insoluble filler, pigment and 
the like other than the polymer component to obtain a corrected final 
weight (Y). On one hand, from the weight of the sample pellets is deducted 
a total weight of cyclohexane-insoluble components other than the 
ethylene/.alpha.-olefin copolymer, for example, a mineral oil or 
plasticizer, cyclohexane-soluble rubber, and insoluble components other 
than the polyolefin resin, such as a filler, pigment and the like, to 
obtain a corrected initial weight (X). 
The gel content is decided from those values according to the following 
equation. 
##EQU1## 
The thermoplastic elastomers having the compositions as mentioned above are 
fed to a plastic processing machine such as an extruder equipped with 
T-die, a calender molding machine, etc., and molded according to the usual 
method into a desired form such as sheet-like article. At the time of 
molding the thermoplastic elastomer, desired pattern (emboss) may be 
formed on the sheet surface. Molded articles of thermoplastic elastomer 
thus molded have excellent physical properties, for example, weathering 
resistance, heat resistance, cold resistance or resistance to light. 
To obtain a sheet-like article by molding the thermoplastic elastomer into 
sheet-like form, it is particularly preferable to use as the thermoplastic 
elastomer a partially cross-linked product of an ethylene/.alpha.-olefin 
copolymer rubber obtained by dynamically crosslinking a mixture containing 
(a) 30-50 parts by weight of an ethylene/.alpha.-olefin copolymer and (b) 
20-40 parts by weight of a polypropylene resin and 20-40 parts by weight 
of a polyethylene resin and, if necessary, (c) a peroxide non-crosslinking 
type hydrocarbon rubbery substance and/or (d) a mineral oil, because the 
sheet-like article 50 obtained is excellent in physical properties. 
The content ratio between the components (a) an ethylene/.alpha.-olefin 
copolymer and (b) a polyolefin resin in the thermoplastic elastomers can 
be determined by the D.S.C. method or the infrared absorbency analysis 
method. The contents of the components (c) a peroxide non-crosslinking 
type hydrocarbon rubbery sustance or (d) a mineral oil type softening 
agent in the composition can be determined by the solvent extraction 
method (Soxhlet extraction method using acetone as the solvent) or the 
infrared absorbance analysis method. 
In the present invention, on the surface of a molded article of the 
above-mentioned thermoplastic elastomer, a primer layer containin at least 
one compound selected from among saturated polyesters and chlorinated 
polyolefins is first formed. To form the primer layer on the surface of 
the molded article, it is sufficient that at least one compound selected 
from among saturated polyesters and chlorinated polyolefins is dissolved 
in an organic solvent and a coating solution for forming the primer layer 
is coated according to the usual method on the surface of the molded 
article. 
Saturated polyester resins used for forming the primer layer include 
polyethylene terephthalate, polybutylene terephthalate and derivatives 
thereof. Chlorinated polyolefin resins used for the same purpose include 
chlorinated polyethylene, chlorinated polypropylene, ethylene 
chloride/.alpha.-olefin copolymers. 
The coating solution for forming the primer layer may have incorporated 
therein, if necessary, silicic acid anhydride (silica), pigments, 
delustering agents, etc. in addition to the above-mentioned saturated 
polyester resin or chlorinated ethylene/.alpha.-olefin copolymer. 
In particular, the addition to the coating solution of silicic acid 
anhydride in an amout of up 100% by weight of the aforesaid polyester 
resin or chlorinated polyolefin is preferred. 
The organic solvents used for dissolving the saturated polyester resin or 
chlorinated polyolefin resin include toluene, methyl ethyl ketone, ethyl 
acetate, methylene chloride, cyclohexanone, etc. 
Of these solvents, particularly useful is a mixed solvent comprising 
toluene and methyl ethyl ketone. The solids concentration in the coating 
solution for forming the primer layer is 2-50% by weight, preferably about 
10-15% by weight. 
The film thickness of the primer layer formed on the surface of the molded 
article, prepared from the thermoplastic elastomer, is preferably about 
10-20 .mu.m. 
When the primer layer mentioned above is formed on the molded article of 
thermoplastic elastomer, the primer-forming coating solution may be 
applied in a plurality of steps and, in that case, a plurality of primer 
forming-coating solutions having different compositions, but within the 
scope as specified in the present invention, may be used. 
In the present invention, moreover, there can be provided, in addition to 
the aforesaid primer layer (an undercoat layer), a print ink layer (a 
second primer layer) which is formed between said primer layer and the 
aforesaid topcoat layer. In that case, the print ink layer may be formed 
by the use of a coating solution for forming the print ink layer, said 
coating solution being prepared by dissolving polyvinyl chloride and a 
pigment, or polyester and a pigment or acrylic resin and a pigment, in 
such a solvent as toluene or methyl ethyl ketone. 
On the surface of the primer layer formed in the above manner on the molded 
article of thermoplastic elastomer, a topcoat layer containing at least 
one compound selected from the group of saturated polyesters, polyvinyl 
chloride, acrylic ester resins and polyisocyanate is formed. When the 
primer layer contains only a saturated polyester, out of the saturated 
polyesters and chlorinated polyolefins as specified above, the topcoat 
layer to be formed must contain at least an acrylic ester resin. 
To form the topcoat layer on the primer layer, it is sufficient that at 
least one compound selected from the group of saturated polyesters, 
acrylic ester, polyvinyl chloride resins and polyisocyanate is dissolved 
in an organic solvent, and the topcoat forming coating solution 50 
obtained is coated according to conventional methods on the primer layer. 
Saturated polyesters used for forming the topcoat include polyethylene 
terephthalate, polybutylene terephthalate and derivatives thereof. Acrylic 
ester resins used for the same purpose include (poly)methyl methacrylate, 
(poly)butyl methacrylate, (poly)isobutyl methacrylate, (poly)-2-ethylhexyl 
methacrylate, etc. Similarly, isocyanate resins include 
(poly)hexamethylene diisocyanate, (poly)isophorone diisocyanate, etc. 
When the acrylic ester resin is contained in the topcoat layer, the surface 
of the molded articles becomes difficult to scratch. If the isocyanate 
resin is incorporated into the topcoat layer, the topcoat layer comes to 
have excellent surface characteristics and, at the same time, the 
incorporated isocyanate resin reacts with the primer layer or the 
thermoplastic elastomer, whereby the topcoat layer strongly adheres to the 
primer layer and the molded article of thermoplastic elastomer. 
Furthermore, if the saturated polyester is contained in the topcoat layer, 
a topcoat layer excellent in surface characteristics is obtained and, at 
the same time, integrity between the saturated polyester and the acrylic 
ester resin or the polyisocyanate can be maintained satisfactorily. 
The topcoat layer used in the present invention preferably contains a 
combination of 80-10 parts by weight of an acrylic acid ester resin, 10-80 
parts by weight of polyvinyl chloride and 10-60 parts by weight of silicic 
acid anhydride (silica); a combination of 95-5 parts by weight of a 
saturated polyester resin and 5-95 parts by weight of a polyisocyanate; a 
combination of 95-5 parts by weight of a polyisocyanate; or a combination 
of 80-15 parts by weight of a saturated polyester resin, 15-85 parts by 
weight of an acrylic ester resin and 20-5 parts by weight of a 
polyisocyanate. Of these combinations, a combination which contains the 
saturated polyester resin, acrylic ester resin and polyisocyanate is 
preferred. 
In the present invention, it is necessary that the primer layer is first 
formed on the surface of the molded article of thermoplastic elastomer and 
then the topcoat layer is formed on the surface of said primer layer. If 
the topcoat layer is formed directly on the molded article, omitting the 
primer layer, a molded article of the thermoplastic elastomer excellent in 
surface characteristics such as abrasion resistance, crease-flex 
resistance and anti-sticking property cannot be obtained. 
The topcoat forming coating solution may include, if necessary, silicic 
acid anhydride (silica), pigments, delustering agents, etc. in addition to 
at least one compound selected from the group of the above-mentioned 
saturated polyester resins, acrylic ester resins, polyvinyl chloride and 
polyisocyanate. 
In particular, the addition to the coating solution of silicic acid 
anhydride (silica) in an amount of up to 100% by weight, preferably 10-60% 
by weight based on the above-mentioned resin is preferred. 
Organic solvents used for dissolving the above-mentioned resins for use in 
the topcoat layer include methyl ethyl ketone, toluene, xylene, 
cyclohexane, methylene chloride, etc. 
Of these solvents, particularly useful is a mixed solvent comprising 
toluene and methyl ethyl ketone. The solids contents in the coating 
solution for forming the topcoat is 5-50% by weight, preferably about 
10-15% by weight. 
The film thickness of the topcoat layer to be formed in the manner 
mentioned above on the primer layer surface is preferably 3-30 .mu.m, more 
preferably about 10-20 .mu.m. 
To apply the primer layer forming coating solution and the topcoat layer 
coating solution, respectively, to the surface of the molded article of 
thermoplastic elastomer and that of the primer layer, there may be adopted 
the conventional coating methods using, for example, a gravure roll 
coater, roll coater, knife coater, screen coater, sprayer, etc. 
Furthermore, the surface of molded articles of the thermoplastic elastomer 
of the present invention may be subjected, to corona discharge treatment 
prior to forming the primer layer. 
In accordance with the present invention, it becomes possible to markedly 
improve the surface characteristics of the molded articles of the 
thermoplastic elastomer by forming the primer layer and topcoat layer on 
the surface of said molded articles. That is, the molded articles of 
thermoplastic elastomer used in the present invention have excellent 
physical properties, but, on the other hand, they have such problems that 
because they are of the polyolefin system, they are poor in scratch 
resistance of the surface and the surface thereof is apt to be attacked by 
hydrocarbon solvents. However, by virtue of forming the above-mentioned 
primer (undercoat) and topcoat layers on the surface of molded articles of 
thermoplastic elastomer in accordance with the present invention, the 
molded articles can be improved in abrasion resistance, anti-scratching 
properties, etc. and, moreover, surface gloss and surface touch of the 
molded article can be maintained in the optimal state. Furthermore, the 
above-mentioned primer and topcoat layer have excellent adhesion to the 
molded articles and, at the same time, have excellent adaptability to 
thermal deformation treatment of the molded articles. 
EFFECT OF THE INVENTION 
The molded articles of thermoplastic elastomer of the present invention 
have such excellent surface characteristics that the surface thereof is 
hard to scratch and excellent in external appearance as well as in touch 
and, moreover, the surface thereof is hard to subject to an attack by 
hydrocarbon solvents, since the present molded articles have the primer 
layer having a specific composition and the topcoat layer having a 
specific composition formed on the surface of molded articles prepared 
from the thermoplastic elastomer containing a polyolefin resin and a 
partially cross-linked product of ethylene/.alpha.-olefin copolymer 
rubber. 
The molded articles of the present invention are used as leather-like 
products for the manufacture of sheet materials for interior automotive 
decoration (e.g. door, ceiling, seat, etc.), coverings (outer surface 
materials) for furniture such as chair, sofa, etc., covers of case, bag, 
book, etc., handbag and purse, etc. 
The present invention is illustrated below with reference to the examples, 
but it should be construed that the invention is in no way limited to 
those examples. 
In the following examples, surface characteristics of a coating comprising 
a primer layer and topcoat layer formed on the surface of molded article 
of thermoplastic elastomer were evaluated in the following manner. 
1. 1. Adhesion of coating 
Two days after coating, 100 squares are formed on the surface of coating by 
cutting said surface with a sharp-edged razor to give 11 cuts in parallel 
line at intervals of 2 mm, and 11 cuts in parallel line at intervals of 2 
mm crossing at right angles thereover, thereby forming 100 squares of 2 mm 
of the coating. An adhesive cellophane tape, a product of Nichiban Co., 
Ltd., is then applied to the whole surface of the 100 squares thus formed, 
and immediately thereafter the tape is vigorously peeled off therefrom to 
examine the number of squares peeled off from the molded article surface. 
(The above test is hereinafter called the cross-cut adhesion test for 
short.) 
The results obtained in the test were represented in terms of values 
calculated on the basis of the following formula. 
##EQU2## 
______________________________________ 
Example 
______________________________________ 
When no squares were detached at all 
100/100 
When all the squares were detached 
0/100 
______________________________________ 
1. 2. Abrasion resistance test 
Using a revolving vibrator type crockmeter as stipulated in 4. (1) of JIS 
L-0849, the surface of sheet is abraded 200 times under a continuous load 
of 500 g with Kanekin No. 3 as stipulated in an annexed table of JIS 
L-0803, and change in appearance of the surface of sheet thus abraded is 
evaluated according to the following ratings from A to E. 
A. No change is observed at all in appearance of the surface tested. 
B. Traces of the cotton fabric are left slightly on the surface tested. 
C. The surface tested is injured. 
D. The surface tested undergoes blushing. 
E. Not only the surface tested but also the substrate thereof is destroyed. 
1. 3. Crease-flex resistance test 
Test sheet specimens, 3 cm.times.12 cm, are taken out of the molded sheet 
in a uniform direction, either longitudinally or laterally, in accordance 
with 5.17 Frictional Force, C Method (Scott Shape Method) as stipulated in 
JIS L-1005, and each specimen is fixed between two slide fasteners placed 
at an interval of 2 cm. The specimen thus fixed is frictioned back and 
forth 1000 times for a distance of 4 cm under a pressure loading of 1 kg 
(or 500 gr). 
Ratings 
A. No change is observed at all in appearance of the test specimen. 
B. Blushing is observed slightly. 
C. Blushing or peeling is observed. 
1. 4. Anti-sticking test 
The test is conducted in accordance with 9.7 Non-sticking Test as 
stipulated in JIS K-6772. 
Two sheets of the test specimen, 90 mm.times.60 mm, are put one upon 
another so that their surfaces face to face, placed between two sheets of 
smooth glass plate, 60 mm.times.60 mm, and the resulting assembly on which 
a 2 kg weight is placed is allowed to stand for 24 hours in an air 
thermostat kept at 70.degree. C..+-.2.degree. C. The assembly is then 
taken out of the thermostat and the weight is removed therefrom, followed 
by allowing to cool for 1 hour at room temperature. The two test specimens 
thus treated are peeled off gently from each other to examine whether any 
change occurs on the surfaces of the test specimens thus peeled. 
Ratings 
A. No change such as damage or sticking is observed. 
B. Sticking is observed to some extent. 
C. Damage is observed. 
1. 5. Solvent resistance test 
The surface of the test specimen is strongly wiped with flannel impregnated 
with industrial gasoline to examine whether change occurs or not on the 
wiped surface. 
Ratings 
A. No change is observed at all. 
B. Traces of cloudiness or the like are observed. 
C. Damages caused by peeling or dissolving occur. 
1. 6. Scratch test 
A test specimen of 120 mm in diameter having perforated a hole of 6 mm in 
diameter in the center of said specimen was fixed by adhesion onto a turn 
table of a taper type scratch tester. 
First, the cutterblade edge is placed quietly on the specimen under a load 
of 100 g so that said edge is in contact with the surface of the specimen 
on the turn table, and a switch of the tester is actuated to rotate the 
specimen at a rate of 0.5 or 1.0 rpm so that the edge scratches the 
surface of said specimen for a length of at least 1.5 mm, whereby the 
specimen tested is examined as to whether a scratch is formed or not on 
the outer skin of the specimen surface. 
Next, the edge is lifted and the specimen is allowed to rotate, thereafter 
the edge is placed on the specimen under an increased load of 200 g, and 
the specimen is rotated so that the edge scratches another portion of the 
surface of said specimen to investigate whether the outer skin of the 
specimen surface is scratched or not. In case, no scratch is observed, the 
test is continued while increasing the load further to 300 g, 400 g or a 
larger one, and during this test the load is visually obtained, under 
which the outer skin of the specimen surface is scratched or broken, said 
load being taken as a scratch strength. 
1. 7. Light resistance 
A test specimen of 70 mm in width and 200 mm in length is attached to a 
fade-o-meter, and the specimen is irradiated for 400 hours at a black 
panel temperature of 83.degree..+-.3.degree. C. to visually observe the 
degree change or fading in color of the outer skin of the specimen 
surface. The test specimen is evaluated for light resistance according to 
the following Ratings. 
1. 8. Moisture resistance 
A test specimen of 100 mm.times.100 mm is placed in a thermo-hygrostant 
kept at 50.degree. C..+-.2.degree. C., and after the lapse of 400 hours 
the surface condition of the specimen is visually observed to evaluate 
moisture resistance thereof according to the following Ratings. 
1. 9. Heat resistance 
A test speciment of 100 mm.times.100 mm is placed in a thermostat kept at 
100.degree. C..+-.2.degree. C., and after the lapse of 400 hours the 
surface condition of the specimen is visually observed to evaluate heat 
resistance thereof according to the following Ratings. 
Ratings 
A. No change is observed at all. 
B. Almost inconspicuous, though a slight change is observed. 
C. Less conspicuous, though change is observed apparently. 
D. Change is somewhat noteworthy. 
E. Change is considerably remarkable.

EXAMPLE 1 
Step (1) 
Preparation of thermoplastic elastomer 
Using the following components, a themoplastic elastomer was prepared in 
the manner as mentioned hereinafter. 
(A component): Ethylene/propylene/ethylidene norbornene copolymer rubber; 
Ethylene unit/propylene unit (molar ratio): 78/22, Iodine value 15, Mooney 
viscosity (ML.sub.1+4, 121.degree. C.) 61 
(B component): Isotactic polypropylene resin; Melt index 13 g/10 min 
(230.degree.) 
(C component): Naphthene type process oil 
(D component): A mixture comprising 20% by weight of 
1,3-bis(tert-butylperoxypropyl)benzene, 30% by weight of divinylbenzene 
and 50% by weight of paraffin type mineral oil 
In a Banbury mixer, a mixture comprising 55 parts by weight of (A 
component), 45 parts by weight of (B component) and 30 parts by weight of 
(C component) was kneaded in a nitrogen atmosphere at 180.degree. C. for 5 
minutes, and the resulting kneaded product was formed with a sheet cutter 
into square pellets. 
In a henschel mixer, a mixture comprising 100 parts by weight of the square 
pellets obtained above and 1 part by weight, based on the square pellets, 
of (D component) was kneaded, and the kneaded product obtained was 
extruded in a nitrogen atmosphere at 220.degree. C. with an extruder to 
prepare a thermoplastic elastomer. 
Step (2) 
Preparation of sheet-like molded article 
The thermoplastic elastomer thus prepared was extruded with a 90 mm T-die 
extrusion molding machine manufactured and sold by Toshiba under such 
conditions that a screw is a full-flighted screw, L/D is 22, an extrusion 
temperature is 220.degree. C., T-die is a coat hanger die, and a haul-off 
speed is 5 m/min, and cooled with a chill roll to prepare a sheet. 
Step (3) 
Surface treatment step 
On the surface of the sheet prepared above was coated one time a coating 
solution for forming a first primer layer comprising 10 parts by weight of 
chlorinated polypropylene, 2 parts by weight of silicic acid anhydride and 
88 parts by weight of toluene with a gravure roll of 120 meshes, followed 
by drying at 70.degree. C. for 20 seconds. 
On the surface of the first primer layer thus formed was coated a coating 
solution for forming a second primer layer comprising 8 parts by weight of 
polyvinyl chloride, 2 parts by weight of a pigment and 90 parts by weight 
of methyl ethyl ketone with a gravure roll to print a cloud pattern 
thereon, followed by drying at 70.degree. C. for 20 seconds. 
On the surface of the second primer layer thus formed was then coated one 
time a coating solution for forming a topcoat layer comprising 5 parts by 
weight of polyvinyl chloride, 5 parts by weight of polyacrylic ester, 3 
parts by weight of silicic acid anhydride and 87 parts by weight of methyl 
ethyl ketone with a gravure roll of 100 meshes. With a far infrared 
heater, the sheet thus formed was heated until the surface temperature 
rises up to 180.degree. C. and the surface of the sheet was subjected to 
emboss treatment. 
Physical properties of the sheet-like molded articles obtained are shown in 
Table 1. 
COMATIVE EXAMPLE 1 
Substantially the same procedure as described in Example 1 was repeated 
except that no coating solutions for forming the primer layers were 
applied to the surface of the sheet in the step (3) of Example 1. 
Physical properties of the sheet-like molded article obtained are shown in 
Table 1. 
EXAMPLE 2 
Step (1) 
Preparation of thermoplastic elastomer 
The step (1) of Example 1 was repeated. 
Step (2) 
Preparation of sheet-like molded article 
The step (2) of Example 1 was repeated except that 80 parts by weight of 
the thermoplastic elastomer prepared above and 20 parts by weight, based 
on the thermoplastic elastomer, of a low density polyethylene Density 
0.917 g/cm.sup.3, Melt index 6.5 g/10 min (190.degree. C.) were 
dryblended, and the blend obtained was fed to the T-die extrusion molding 
machine. 
Step (3) 
Surface treatment step 
The step (3) of Example 1 was repeated. 
Physical properties of the sheet-like molded article are shown in Table 1. 
COMATIVE EXAMPLE 2 
Substantially the same procedure as described in Example 2 was repeated 
except that no coating solutions for forming the primer layers were not 
applied to the surface of the sheet in the step (3) of Example 2. 
Physical properties of the surface of the sheet-like molded article 
obtained are shown in Table 1. 
EXAMPLE 3 
Step (1) 
Preparation of thermoplastic elastomer 
The step (1) of Example 1 was repeated except that (C component), i.e. 
naphthene type process oil was not used. 
Step (2) 
Preparation of sheet-like molded article 
The step (2) of Example 1 was repeated. 
Step (3) 
Surface treatment step 
The sheet surface was subjected to oxidation treatment with a solid-state 
corona discharge treatment device until the surface tension thereof 
becomes 45 dyne/cm. 
The thus corona treated surface of the sheet was coated one time with a 
coating solution for forming a first primer layer comprising 9 parts by 
weight of a saturated polyester, 2 parts by weight of silicic acid 
anhydride, 1 part by weight of polyisocyanate, 50 parts by weight of 
toluene and 38 parts by weight of methyl ethyl ketone using a 120-mesh 
gravure roll, followed by drying at 80.degree. C. for 15 seconds. 
Subsequently, a cloud pattern was printed on the surface of the first 
primer layer thus formed with a gravure roll using a letter printing ink 
comprising 10 parts by weight of a saturated polyester, 2 parts by weight 
of a pigment, 50 parts by weight of toluene and 38 parts by weight of 
methyl ethyl ketone. 
Furthermore, on the thus printed first prime layer, was coated a coating 
solution for forming a topcoat layer comprising 2 parts by weight of a 
saturated polyester, 7 parts by weight of polyacrylic ester, 2 parts by 
weight of silicic acid anhydride, 1 part by weight of polyisocyanate, 50 
parts by weight of toluene and 38 parts by weight of methyl ethyl ketone 
using a 120-mesh gravure roll, followed by placing in a thermostat kept at 
30.degree. C. and curing for 24 hours. 
COMATIVE EXAMPLE 3 
Substantially the same procedure as described in Example 3 was repeated 
except that no coating solution for forming the primer layer was not 
coated on the sheet surface in the step (3) of Example 1. 
Physical properties of the surface of the sheet obtained are shown in Table 
1. 
EXAMPLE 4 
Step (1) 
Preparation of thermoplastic elastomer 
A thermoplastic elastomer was prepared by using the following (E component) 
in the manner as mentioned hereinafter. 
(E component): A low density polyethylene having a melt index of 2 g/10 min 
(190.degree. C.) and a density of 0.920 g/cm.sup.3. 
A mixture comprising 50 parts by weight of (A component), 25 parts by 
weight of (B component) and 25 parts by weight of (E component) was 
kneaded with a Banbury mixer in a nitrogen atmosphere at 180.degree. C. 
for 5 minutes, and the kneadate was formed with a sheet cutter into square 
pellets. With a Henschel mixer, 100 parts by weight of the square pellets 
was mixed with 1 part by weight, based on the square pellets, of (D 
component) and extruded with an extruder in a nitrogen atmosphere at 
220.degree. C. to prepare the thermoplastic elastomer. 
Step (2) 
Preparation of sheet-like molded article 
The step (2) of Example 1 was repeated. 
Step (3) 
Surface treatment step 
On the sheet prepared above, was coated one time a coating solution for 
forming a primer layer comprising 10 parts by weight of chlorinated 
polypropylene, 2 parts by weight of silicic acid anhydride and 88 parts by 
weight of toluene using a 120-mesh gravure roll, followed by drying at 
60.degree. C. for 30 seconds. 
Subsequently, on the surface of the primer layer thus formed was coated one 
time a coating solution for forming a topcoat layer comprising 2 parts by 
weight of a saturated polyester, 8 parts by weight of polyacrylic ester, 2 
parts by weight of silicic acid anhydride, 50 parts by weight of toluene 
and 38 parts by weight of methyl ethyl ketone using a 120-mesh gravure 
roll. 
Physical properties of the surface of the sheet obtained are shown in Table 
1. 
COMATIVE EXAMPLE 4 
Substantially the same procedure as described in Example 4 was repeated 
except that the coating solution for forming the primer layer was not 
applied to the sheet surface in the step (3) of Example 4. 
Physical properties of the surface of the sheet-like molded article 
obtained are shown in Table 1. 
EXAMPLE 5 
Substantially the same procedure as described in Example 1 was repeated 
except that the step (2) was carried out in the following manner. 
Step (2) 
Preparation of sheet-like molded article 
The thermoplastic elastomer prepared was fed to a calender molding machine 
(18 B) manufactured and sold by Ishihara K. K. and processed at a hauling 
off speed of 30 m/min and 185.degree. C. to prepare a sheet of 0.5 mm in 
thickness. 
Physical properties of the surface of the sheet-like molded article are 
shown in Table 1. 
COMATIVE EXAMPLE 5 
Substantially the same procedure as described in Example 5 was repeated 
except that the coating solutions for forming primer layers were not 
applied to the sheet surface in the step (3) of Example 5. 
Physical properties of the surface of the sheet-like molded article 
prepared are shown in Table 1. 
TABLE 1 
__________________________________________________________________________ 
Compar. Compar. Compar. Compar. Compar. 
Example Ex. 1 
Ex. 1 Ex. 2 
Ex. 2 
Ex. 3 
Ex. 3 
Ex. 4 
Ex. 4 
Ex. 
Ex. 
__________________________________________________________________________ 
5 
Adhesion of 
coating: 
Cross-cut 100/100 
0/100 100/100 
0/100 
100/100 
3/100 
100/100 
0/100 
100/100 
0/100 
adhesion 
test 
Abrasion B D A D A C A D B D 
resistance 
test 
Crease-flex A C A C A B A C A C 
resistance 
test 
Anti-sticking 
A B A B A A A B A B 
test 
Solvent B C B C A B B C B C 
resistance 
test 
Scratch test 
300 g 
200 g 300 g 
200 g 
300 g 
200 g 
300 g 
200 g 
300 
200 g 
Light resistance 
A B A B A B A B A B 
Moisture resistance 
A A A A A A A A A A 
Heat resistance 
A B A B A A A B A B 
__________________________________________________________________________