Thermoplastic elastomer composition

A thermoplastic elastomer composition which comprises (I) 99 to 1% by weight of a hydrogenated diene copolymer having a number average molecular weight of 50000 to 700,000 in which 80% or more of the double bonds of the conjugated diene portion of the conjugated diene polymer have been saturated, (II) 1 to 99% by weight of an ionomer resin having an .alpha.-olefin unit having 2 to 8 carbon atoms and an .alpha.,.beta.-unsaturated carboxylic acid unit, at least part of the carboxyl group of said unsaturated carboxylic acid unit having been neutralized with a metal ion, and (III) 0 to 70% by weight of a polyolefin resin, provided that (I)+(II)+(III)=100% by weight. Said composition is excellent in moldability and gives a molded article excellent in transparency, flexibility, mechanical strength, heat resistance and impact resilience.

BACKGROUND OF THE INVENTION 
This invention relates to a thermoplastic elastomer composition, and more 
particularly, to a thermoplastic elastomer composition which is excellent 
in flexibility and heat resistance while retaining the excellent 
characteristic features of an ionomer resin per se which are transparency, 
mechanical strength, impact resilience (rebound resilience) and 
moldability. Said thermoplastic elastomer composition can be utilized in 
food uses such as food packaging sheet, cap liner and the like; daily 
sundries uses; sports things such as ski boots, other ski things, golf 
ball coatings, core materials and the like; toy uses; stationary uses such 
as desk mat and the like; automotive exterior and interior trim uses such 
as bumper guard and the like; civil engineering and construction uses such 
as engineering sheets, water-proof sheets and the like; domestic 
appliances such as cleaning corner bumper, refrigerator door seal and the 
like; AV apparatus uses, O.A. business apparatus uses, footwear and 
garment uses such as shoe sole, top lift and the like; textile uses; 
medical apparatus uses; chemical and mining industry materials; packaging 
and transporting materials; materials for agricultural industry, livestock 
industry and fisheries; and the like. 
Ionomer resins in which at least part of the carboxyl group of an 
olefin-unsaturated carboxylic acid copolymer has been neutralized with a 
metal ion are widely used in the above-mentioned fields utilizing 
excellent properties, for example, abrasion resistance, transparency, 
stretchability, heat-sealability, oil resistance, hygienic quality, impact 
resistance, elasticity, flexure resistance, toughness, mechanical 
strength, coatability, adhesiveness, moldability and the like. Since they 
are, however, thermoplastic resins having a relatively low melting point, 
they have such disadvantages that when they are placed at a high 
temperature during use or secondary processing they tend to be deformed or 
broken by heat. Moreover, in respect of flexibility, a further improvement 
has been desired. 
In order to solving the above problems, it has been considered to 
polymer-blend a resin having excellent heat resistance with the above 
ionomer resin to impart heat deformation resistance to the ionomer resin; 
however, the ionomer resins generally lack consistency with almost all 
resins, so that the resulting blend exhibits a delamination phenomenon, 
sufficient toughness and impact resistance are not obtained, and the 
flexibility is not improved. 
For example, Japanese Patent Application Kokai No. 63-170,442 proposes 
blending an acrylic resin with the ionomer resin; however, this can be 
used only on the assumption that delamination is caused, and the 
flexibility of the resulting composition is not improved. Japanese Patent 
Application Kokai No. 60-71,653 proposes blending a propylene copolymer 
with the ionomer resin; however, this does not solve the delamination and 
flexibility problems similarly to the above. 
On the other hand, when a soft elastomer such as ethylene-propylene rubber 
or the like is blended, there is such a problem that the characteristics 
inherent to the ionomer resin are lost, for example, the resulting 
composition is not transparent and the strength thereof is remarkably 
reduced. 
When a softening agent such as an oil, a plasticizer or the like is added, 
there is such a problem that the softening agent bleeds to the surface of 
the resulting molded article to impair the appearance of the molded 
article, and the amount of the softening agent used is limited. As a 
result, only a hard molded article is obtained. 
SUMMARY OF THE INVENTION 
The present inventors have made extensive research to find such a 
surprising fact that when a hydrogenated diene copolymer is blended with 
the ionomer resin and, if necessary, an olefin resin is combined 
therewith, an elastomer composition excellent in flexibility and heat 
resistance is obtained while retaining the excellent characteristics 
inherent to the ionomer including mechanical strength, impact resilience, 
moldability and the like. 
An object of this invention is to solve the above problems. 
Another object of this invention is to provide a novel elastomer 
composition excellent in flexibility and heat resistance while retaining 
the excellent characteristics inherent to the above-mentioned ionomer 
resin including transparency, mechanical strength, impact resilience, 
moldability and the like. 
Other objects and advantages of this invention will become apparent from 
the following description. 
According to this invention, there is provided a thermoplastic elastomer 
composition which comprises (I) 99 to 1% by weight of a hydrogenated diene 
copolymer having a number average molecular weight of 50,000 to 700,000 in 
which 80% or more of the double bonds of the conjugated diene portion of 
the conjugated diene polymer have been saturated, (II) 1 to 99% by weight 
of an ionomer resin having an .alpha.-olefin unit having 2 to 8 carbon 
atoms and an .alpha.,.beta.-unsaturated carboxylic acid unit, at least 
part of the carboxyl group of said unsaturated carboxylic acid unit having 
been neutralized with a metal ion, and (III) 0 to 70% by weight of a 
polyolefin resin, provided that (I)+(II)+(III)=100% by weight. 
DETAILED DESCRIPTION OF THE INVENTION 
The component (I) of this invention is a hydrogenated diene polymer having 
a number average molecular weight of 50,000 to 700,000, preferably 100,000 
to 600,000 in which at least 80%, preferably at least 90%, more preferably 
at least 95% of the double bonds of the conjugated diene portion of the 
conjugated diene polymer have been saturated (namely, the hydrogenation 
degree is at least 80%, preferably at least 90% and more preferably at 
least 95%). 
When the hydrogenation degree is less than 80%, the composition is inferior 
in transparency, mechanical strength, heat resistance and weather 
resistance. When the number average molecular weight is less than 50,000, 
blocking tends to be caused when the resulting hydrogenated diene 
copolymer is pelletized, and in addition, when the composition is blended 
with other resins, the resulting blend is inferior in mechanical strength 
and appearance of molded article. When the number average molecular weight 
is more than 70,000, the composition is inferior in moldability. 
The hydrogenated diene polymer (I) includes hydrogenated products of diene 
polymers, for example, homopolymers of conjugated dienes, random 
copolymers of conjugated dienes with alkenyl aromatic compounds, block 
copolymers each consisting of an alkenyl aromatic compound polymer block 
and a conjugated diene polymer block, block copolymers each consisting of 
an alkenyl aromatic compound polymer block and an alkenyl aromatic 
compound-conjugated diene copolymer block and these polymers and 
copolymers modified with a functional group. 
The hydrogenated diene polymer (I) is preferably at least one member 
selected from the following hydrogenated diene copolymers (I-1), (I-2) and 
(I-3), and in this case, the thermoplastic elastomer composition has more 
improved flexibility and heat resistance while retaining the excellent 
characteristics inherent to the ionomer resin including transparency, 
impact resilience, mechanical strength, moldability and the like: 
(I-1) A hydrogenated diene copolymer having a number average molecular 
weight of 50,000 to 700,000 obtained by hydrogenating (i) an (A)-(B) or 
(A)-(B)-(A) block copolymer in which (A) means an alkenyl aromatic 
compound polymer block referred to hereinafter as the block (A)! and (B) 
means a conjugated diene polymer block or a random alkenyl aromatic 
compound-conjugated diene copolymer block referred to hereinafter as the 
block (B)!, (ii) an (A)-(B)-(C) block copolymer in which (A) and (B) are 
defined as above and (C) means a tapered alkenyl aromatic 
compound-conjugated diene copolymer block in which the alkenyl aromatic 
compound proportion increases gradually referred to hereinafter as the 
block (C)! or (iii) a functional group-modified (A)-(B), (A)-(B)-(A) or 
(A)-(B)-(C) block copolymer, in which block copolymers (i), (ii) and 
(iii), 
(1) the alkenyl aromatic compound/conjugated diene weight ratio in all the 
monomers constituting the hydrogenated diene copolymer (I-1) is 5/95 to 
60/40, 
(2) the total amount of the bound alkenyl aromatic compound in the block 
(A) and the bound alkenyl aromatic compound in the block (C) is 3 to 50% 
by weight of the total weight of all the monomers constituting the 
hydrogenated diene copolymer (I-1) and the amount of the bound alkenyl 
aromatic compound in the block (A) is at least 3% by weight of the total 
weight of all the monomers constituting the hydrogenated diene copolymer 
(I-1), and 
(3) the vinyl content of the conjugated diene portion of the block (B) is 
more than 20%; or (iv) the block copolymer (i), (ii) or (iii) whose 
polymer block has been extended or branched through a coupling agent 
residue, to saturate 80% or more of the double bonds in the conjugated 
diene portion. 
(I-2) A hydrogenated diene copolymer having a number average molecular 
weight of 50,000 to 700,000 obtained by hydrogenating (v) a (D)-(E)-(F) 
block copolymer in which (D) means a polymer block comprising mainly an 
alkenyl aromatic compound referred to hereinafter as the block (D)!, (E) 
means a polymer block comprising mainly a conjugated diene having a 
1,2-vinyl content of more than 25% but not more than 95% referred to 
hereinafter as the block (E)! and (F) means a polymer block of 
polybutadiene having a 1,2-vinyl content of not more than 25% referred to 
hereinafter as the block (F)! or (vi) a functional group-modified 
(D)-(E)-(F) block copolymer, in which block copolymers (v) and (vi), 
(1) the content of the block (D) is 5 to 60% by weight, 
(2) the content of the block (E) is 30 to 90% by weight, and 
(3) the content of the block (F) is 5 to 60% by weight, provided that 
(D)+(E)+(F)=100% by weight, or (vii) the block copolymer (v) or (vi) whose 
polymer block has been extended or branched through a coupling agent 
residue, to saturate 80% or more of the double bonds in the conjugated 
diene portion. 
(I-3) A hydrogenated diene copolymer having a number average molecular 
weight of 50,000 to 700,000 obtained by hydrogenating (viii) a (G)-(H) or 
(G)-(H)-(G) block copolymer in which (G) means a polymer block of 
polybutadiene having a 1,2-vinyl content of not more than 25% referred to 
hereinafter as the block (G)! and (H) means a polymer block comprising 
mainly a conjugated diene, whose conjugated diene portion has a vinyl 
content of more than 25% referred to hereinafter as the block (H)! or 
(ix) the block copolymer (viii) whose polymer block has been extended or 
branched through a coupling agent residue, to saturate 80% or more of the 
double bonds in the conjugated portion, or the hydrogenated diene polymer 
modified with a functional group. 
The hydrogenated diene polymer (I) is explained below referring to the 
hydrogenated diene copolymers (I-1), (I-2) and (I-3). 
The hydrogenated diene copolymer (I-1) 
The alkenyl aromatic compound which is one of the constituents of the 
hydrogenated diene copolymer (I-1) is preferably styrene, t-butylstyrene, 
.alpha.-methylstyrene, p-methylstyrene, divinylbenzene, 
1,1-diphenylstyrene, N,N-dimethyl-p-aminoethylstyrene, 
N,N-diethyl-p-aminoethylstyrene, vinylpyridine or the like, and more 
preferably styrene or .alpha.-methylstyrene. These alkenyl aromatic 
compounds are used alone or in admixture of two or more. The conjugated 
diene which is another constituent of the hydrogenated diene copolymer 
(I-1) is preferably 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 
1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 
4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene or chloroprene, more 
preferably 1,3-butadiene, isoprene or 1,3-pentadiene, and most preferably 
1,3-butadiene. 
The block (A) in the hydrogenated diene copolymer (I-1) is a polymer block 
comprising mainly an alkenyl aromatic compound and this polymer block may 
comprise, in the copolymerized form, 10% by weight or less, preferably 5% 
by weight or less, of a vinyl compound copolymerizable therewith. 
The alkenyl aromatic compound/conjugated diene weight ratio in all the 
monomers of the hydrogenated diene copolymer (I-1) is 5/95 to 60/40, 
preferably 7/93 to 50/50. When the proportion of the alkenyl aromatic 
compound is less than 5% by weight (in other words, the proportion of the 
conjugated diene is more than 95% by weight), the mechanical strength, 
processability and heat resistance are inferior and when the hydrogenated 
copolymer obtained is pelletized blocking tends to be caused. When the 
proportion of the alkenyl aromatic compound is more than 60% by weight (in 
other words, the proportion of the conjugated diene is less than 40% by 
weight), the hydrogenated diene copolymer (I-1) becomes resinous and the 
impact resistance, flexibility, low-temperature characteristics and 
transparency are inferior. 
The total amount of the bound alkenyl aromatic compound in the block (A) 
and the bound alkenyl aromatic compound in the block (C) is 3 to 50% by 
weight, preferably 5 to 40% by weight, and more preferably 5 to 30% by 
weight, based on the total weight of all the monomers constituting the 
hydrogenated diene copolymer (I-1). When the total amount of the bound 
alkenyl aromatic compound in the blocks (A) and (C) is less than 3% by 
weight, the heat resistance and mechanical strength are inferior and when 
the hydrogenated diene copolymer is pelletized, blocking tends to be 
caused. In addition, when the hydrogenated diene copolymer is blended with 
other components, processability is inferior. When the total amount of the 
bound alkenyl aromatic compound is more than 50% by weight, the 
transparency, flexibility, processability and low-temperature 
characteristics are inferior. 
The amount of the bound alkenyl aromatic compound in the block (A) is 
preferably at least 3% by weight, more preferably 5 to 30% by weight, of 
the total weight of all the monomers constituting the component (I-1). 
When the amount of the bound alkenyl aromatic compound in the block (A) is 
less than 3% by weight of the total weight of all the monomers of the 
hydrogenated diene copolymer (I-1), the mechanical strength, 
processability and heat resistance tend to become inferior when the 
hydrogenated diene copolymer (I-1) is blended with other components. 
The vinyl content of the conjugated diene portion of the block (B) before 
the hydrogenation is more than 20% by weight, preferably at least 40% by 
weight and more preferably at least 60% by weight. When it is less than 
20% by weight, the flexibility improvement effect becomes low when the 
hydrogenated diene copolymer (I-1) is blended with the ionomer resin (II). 
The hydrogenation degree of the double bonds in the conjugated diene 
portion is 80% or more, preferably 90% by weight and more preferably 95% 
or more. When it is less than 80%, the transparency, heat resistance, 
weather resistance and mechanical strength are inferior. 
Incidentally, the contents of the blocks (A), (B) and (C) in the 
hydrogenated diene copolymer (I-1) are preferably 3 to 50% by weight, 30 
to 97% by weight and 0 to 50% by weight, respectively; more preferably 4 
to 40% by weight, 35 to 94% by weight and 2 to 40% by weight, 
respectively, provided that (A)+(B)+(C)=100% by weight. The number average 
molecular weights of the blocks (A), (B) and (C) are preferably in the 
range of from 1,500 to 350,000, in the range of from 15,000 to 679,000, 
and in the range of from 2,000 to 350,000, respectively; more preferably 
in the range of from 4,000 to 240,000, in the range of from 35,000 to 
564,000 and in the range of from 2,000 to 240,000, respectively. 
The number average molecular weight of the hydrogenated diene copolymer 
(I-1) is 50,000 to 700,000, preferably 100,000 to 600,000. When it is less 
than 50,000, blocking tends to be caused when the hydrogenated diene 
copolymer obtained is pelletized, and the mechanical strength is lowered. 
When it is more than 700,000, the flow property and processability are 
inferior. 
The hydrogenated diene copolymer (I-1) used in this invention can be 
produced by, for example, the method disclosed in Japanese Patent 
Application Kokai No. 3-72,512. 
The hydrogenated diene copolymer (I-1) used in this invention may be a 
hydrogenation product of a block copolymer represented by one of the 
following formulas in which the polymer block has been extended or 
branched by adding a coupling agent: 
(A)-(B)!.sub.p -X, 
(A)-(B)-(C)!.sub.p -X and 
(A)-(B)-(A)!.sub.p -X 
wherein (A), (B) and (C) are as defined above, p is an integer of 2 to 4 
and X is a coupling agent residue. 
The coupling agent which may be used in this case includes, for example, 
diethyl adipate, divinylbenzene, tetrachlorosilane, butyltrichlorosilane, 
methyldichlorosilane, tetrachlorotin, butyltrichlorotin, 
dimethylchlorosilane, tetrachlorogermanium, 1,2-dibromoethane, 
1,4-dichloromethylbenzene, bis(trichlorosilyl)ethane, epoxidized linseed 
oil, tolylene diisocyanate, 1,2,4-benzene triisocyanate and the like. 
The hydrogenated diene copolymer (I-2) 
The alkenyl aromatic compound and conjugated diene used in the hydrogenated 
diene copolymer (I-2) are as defined as to the hydrogenated diene 
copolymer (I-1). 
The block (D) which is one of the constituents of the hydrogenated diene 
copolymer (I-2) is a polymer block comprising mainly an alkenyl aromatic 
compound, and more detailedly speaking, it is preferably an alkenyl 
aromatic compound homopolymer block or a block of copolymer of 90% by 
weight or more of an alkenyl aromatic compound with a conjugated diene in 
which homopolymer and copolymer 80% or more of the double bonds of the 
conjugated diene portion is hydrogenated. When the amount of the alkenyl 
aromatic compound in the block (D) is less than 90% by weight, the 
strength and weather resistance are inferior. The content of the block (D) 
in the hydrogenated diene copolymer (I-2) is 5 to 60% by weight, 
preferably 10 to 50% by weight. When the content of the block (D) is less 
than 5% by weight, the heat resistance and mechanical strength are 
inferior. On the other hand, when it is more than 60% by weight, the 
processability and flexibility are inferior. The number average molecular 
weight of the block (D) is preferably 2,000 to 420,000. 
The content of the block (E) which is one of the constituents of the 
hydrogenated diene copolymer (I-2) is 30 to 90% by weight, preferably 35 
to 80% by weight. When the content of the block (E) is less than 30% by 
weight, the flexibility is lowered, while when it is more than 90% by 
weight, the processability and mechanical strength are lowered. 
The vinyl content of the conjugate diene portion before the hydrogenation 
contained in the block (E) is more than 25 but not more than 95%, 
preferably 30 to 90%. When the conjugated diene portion before the 
hydrogenation of the block (E) has, when the conjugated diene is, for 
example, butadiene, a vinyl content of 25% or less, a polyethylene chain 
is formed upon hydrogenation, whereby the rubbery properties are lost. On 
the other hand, when said 1,2-vinyl content is more than 95%, the glass 
transition temperature of the hydrogenated diene copolymer becomes high 
and the rubbery properties are lost. 
The number average molecular weight of the block (E) is preferably 15,000 
to 630,000, more preferably 35,000 to 420,000, and 80% or more of the 
double bonds of the conjugated diene portion is hydrogenated. 
Moreover, the content of the block (F) which is another constituent of the 
hydrogenated diene copolymer (I-2) is 5 to 60% by weight, preferably 5 to 
50% by weight. When the content of the block (F) is less than 5% by 
weight, the mechanical strength is lowered, while when it is more than 60% 
by weight, the flexibility is inferior. 
The 1,2-vinyl content of the butadiene portion before hydrogenation of the 
polybutadiene block (F) is not more than 25%, preferably less than 20%. 
When it is more than 25%, after the hydrogenation, the resinous properties 
of the hydrogenated diene copolymer are lost and the properties of the 
thermoplastic elastomer as the block copolymer are lost. 
The number average molecular weight of the block (F) is preferably 2,500 to 
420,000 and 80% or more of the double bonds of the butadiene portion of 
the polybutadiene block (F) is hydrogenated. 
The number average molecular weight of the hydrogenated diene copolymer 
(I-2) used in this invention is 50,000 to 700,000, preferably 100,000 to 
600,000, and when it is less than 50,000, the mechanical strength and heat 
resistance of the composition obtained are lowered, while when it is more 
than 700,000, the flow property and processability of the composition are 
lowered. 
The hydrogenated diene copolymer (I-2) used in this invention can be 
obtained by, for example, the method disclosed in Japanese Patent 
Application Kokai No. 2-133,406. 
The hydrogenated diene copolymer (I-2) used in this invention may be a 
hydrogenation product of a block copolymer represented by one of the 
following formulas in which the polymer molecular chain has been extended 
or branched by adding a coupling agent: 
(D)-(E)-(F)!.sub.q -Y and 
(D)-(E)-(F)!-Y- (D)-(E)! 
wherein (D), (E) and (F) are as defined above, q is an integer of 2 to 4 
and Y is the coupling agent residue. 
The coupling agent which may be used in this case includes the same as 
mentioned as to the hydrogenated diene copolymer (I-1). 
The hydrogenated diene copolymer (I-3) 
The alkenyl aromatic compound and conjugated diene used in the hydrogenated 
diene copolymer (I-3) are as defined as to the hydrogenated diene 
copolymer (I-1). 
The hydrogenated diene copolymer (I-3) used in this invention is a 
hydrogenation product obtained by hydrogenating 80% or more of the double 
bonds in the conjugated portion of a block copolymer composed of the 
polybutadiene polymer block (G) having a 1,2-vinyl content of 25% or less 
and the polymer block (H) which is a conjugated diene homopolymer block or 
an alkenyl aromatic compound-conjugated diene copolymer block whose 
conjugated diene portion has a vinyl content of more than 25% but 95% or 
less, the block structure of the said block copolymer being represented by 
(G)-(H) or (G)-(H)-(G), or the (G)-(H) or (G)-(H)-(G) block copolymer 
whose polymer molecular chain has been extended or branched through a 
coupling agent residue. 
The block (G) of the hydrogenated diene copolymer (I-3) is converted by 
hydrogenation into a crystalline polymer block having a structure similar 
to that of a conventional low density polyethylene. The 1,2-vinyl content 
of the polybutadiene before the hydrogenation in the block (G) is 25% or 
less, preferably 20% or less and more preferably 15% or less. When the 
1,2-vinyl content of the polybutadiene before the hydrogenation in the 
block (G) is more than 25%, the lowering of the crystal melting point 
after the hydrogenation is remarkable and the mechanical strength is 
inferior. 
The block (H) is a conjugated diene homopolymer block or an alkenyl 
aromatic compound-conjugated diene copolymer block, and by hydrogenation, 
when the conjugated diene is, for example, butadiene, the block (H) 
becomes a rubbery ethylene-butene-1 copolymer block or a polymer block 
exhibiting a structure similar to an alkenyl aromatic 
compound-ethylene-butene-1 copolymer. 
Incidentally, the amount of the alkenyl aromatic compound used in the block 
(H) is preferably 35% by weight or less, more preferably 30% by weight or 
less, and most preferably 25% by weight or less, of the total weight of 
the monomers constituting the block (H), and when it is more than 35% by 
weight, the glass transition temperature of the block (H) is elevated and 
the low-temperature characteristics and flexibility are inferior. 
The vinyl content of the conjugated diene portion before the hydrogenation 
of the block (H) is more than 25%, preferably more than 25% but not more 
than 95%, more preferably 35 to 85%, and when the vinyl content is 25% or 
less or more than 95%, the block (H) exhibits, when the conjugated diene 
is, for example, butadiene, a crystalline structure due to polyethylene 
chain or polybutene-1 chain, respectively, upon hydrogenation and hence, 
the state thereof becomes resinous and the flexibility thereof becomes 
inferior. 
The block (G)/block (H) weight ratio in the hydrogenated diene copolymer 
(I-3) is preferably 5/95 to 90/10, more preferably 10/90 to 80/20. When 
the amount of the block (G) is less than 5% by weight in other words, the 
amount of the block (H) is more than 95% by weight!, the crystalline 
polymer block becomes insufficient and the mechanical strength is 
inferior. Also, when the amount of the block (G) is more than 90% by 
weight in other words, the amount of the block (H) is less than 10% by 
weight!, the flexibility is inferior. 
In the hydrogenated diene copolymer (I-3) used in this invention, it is 
necessary that at least 80%, preferably at least 90% and more preferably 
at least 95%, of the double bonds in the conjugated diene portion of each 
of the blocks (G) and (H) be saturated by hydrogenation, and when the 
hydrogenation degree is less than 80%, the weather resistance and 
mechanical strength are inferior. 
Incidentally, the weight average molecular weight of the block (G) is 
preferably 2,500 to 630,000, more preferably 10,000 to 480,000. The weight 
average molecular weight of the block (H) is preferably 5,000 to 665,000, 
more preferably 20,000 to 540,000. 
The number average molecular weight of the hydrogenated diene copolymer 
(I-3) used in this invention is 50,000 to 700,000, preferably 100,000 to 
600,000, and when it is less than 50,000 the mechanical strength and heat 
resistance of the composition obtained are lowered, and when it is more 
than 700,000, the flow property, processability and flexibility of the 
composition obtained are inferior. 
The hydrogenated diene copolymer (I-3) used in this invention can be 
prepared by, for example, the method disclosed in Japanese Patent 
Application Kokai No. 3-128,957. 
The hydrogenated diene copolymer (I-3) used in this invention may be a 
hydrogenation product of a block copolymer represented by one of the 
following formulas in which the polymer molecular chain has been extended 
or branched by adding a coupling agent: 
(G)-(H) !.sub.r -Z and 
(G)-(H)-(G)!.sub.r -Z 
wherein (G) and (H) are as defined above, r is an integer of 2 to 4 and Z 
is a coupling agent residue. 
The coupling agent which may be used in this case includes the same as 
mentioned as to the hydrogenated diene copolymer (I-1). 
The hydrogenated diene copolymer (I) used in this invention may be a 
modified hydrogenated diene copolymer modified with a functional group. 
Said modified hydrogenated diene copolymer is a hydrogenated diene 
copolymer containing at least one functional group selected from the group 
consisting of carboxyl group, acid anhydride group, hydroxyl group, epoxy 
group, halogen atom, amino group, isocyanate group, sulfonyl group and 
sulfonate group. 
The method for incorporating the above functional group into the 
hydrogenated diene copolymer includes (1) a method which comprises 
subjecting to copolymerization a conjugated diene or an alkenyl aromatic 
compound having the above functional group in the state that the 
functional group of the monomer is protected to obtain a block polymer, 
subjecting the block polymer to deprotection after completion of the 
copolymerization to add the functional group to the block polymer and then 
hydrogenating the resulting modified block polymer, (2) a method which 
comprises adding a radically polymerizable monomer having a functional 
group to a hydrogenated diene copolymer by a known grafting reaction, and 
(3) a method which comprises kneading a monomer having a functional group 
with a hydrogenated diene copolymer in the presence or absence of an 
organic peroxide or an azo compound by means of a kneader, mixer, extruder 
or the like to add the functional group to the hydrogenated diene 
copolymer. 
By any of these methods, the functional group can be efficiently 
incorporated into the hydrogenated diene copolymer; however, the above 
methods (2) and (3) are simple and effective in industry. 
The amount of the functional group in the modified hydrogenated diene 
copolymer is preferably 0.01 to 10% by weight, more preferably 0.1 to 8% 
by weight and most preferably 0.15 to 5% by weight, based on the 
unmodified hydrogenated diene copolymer. 
The monomer having the functional group for adding the functional group to 
the hydrogenated diene copolymer includes, for example, acrylic acid, 
methacrylic acid, itaconic acid, maleic acid, maleic anhydride, glycidyl 
acrylate, glycidyl methacrylate, allyl glycidyl ether, hydroxyethyl 
methacrylate, hydroxypropyl methacrylate, hydroxyethyl acrylate, 
hydroxypropyl acrylate, dimethylaminoethyl methacrylate and the like. 
The amount of the hydrogenated diene copolymer (I) contained in the 
thermoplastic elastomer composition of this invention is 1 to 99% by 
weight, preferably 5 to 95% by weight and more preferably 10 to 90% by 
weight. When the amount is less than 1% by weight, the flexibility is 
inferior and when the amount is more than 99% by weight, the 
processability is inferior. 
The ionomer resin (II) which is one of the essential constituents of the 
thermoplastic elastomer composition of this invention includes 
.alpha.-olefin copolymers of an .alpha.-olefin having 2 to 8 carbon atoms 
with an .alpha.,.beta.-ethylenically unsaturated carboxylic acid, at least 
part of the carboxyl group in the molecule of said copolymer having been 
neutralized with a metal ion. 
The .alpha.-olefin having 2 to 8 carbon atoms includes, for example, 
straight chain .alpha.-olefins such as ethylene, propylene, butene-1, 
pentene-1, hexene-1, heptene-1, octene-1 and the like and branched chain 
.alpha.-olefins such as 4-methylpentene-1, 4-methylhexene-1, 
4,4-dimethylpentene-1 and the like. Among them, ethylene is preferable. 
These .alpha.-olefins may be used alone or in combination of two or more. 
On the other hand, the .alpha.,.beta.-ethylenically unsaturated carboxylic 
acid includes, for example, .alpha.,.beta.-ethylenically unsaturated 
monocarboxylic acids such as acrylic acid, methacrylic acid, ethacrylic 
acid, crotonic acid and the like; .alpha.,.beta.-ethylenically unsaturated 
dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, 
citraconic acid and the like; and monoesters of the dicarboxylic acids. 
Among them, acrylic acid and methacrylic acid are preferable. These 
.alpha.,.beta.-ethylenically unsaturated carboxylic acids may be used 
alone or in combination of two or more. 
In the copolymer used as the ionomer resin (II), the .alpha.-olefin and the 
.alpha.,.beta.-ethylenically unsaturated carboxylic acid may be 
copolymerized, if necessary, with other monomers copolymerizable 
therewith, for example, acrylic or methacrylic acid esters such as methyl 
methacrylate, methyl acrylate, ethyl acrylate and the like; vinyl esters 
of saturated carboxylic acids such as vinyl acetate, vinyl propionate and 
the like; alkenyl aromatic compounds such as styrene, 
.alpha.-methylstyrene, p-methylstyrene and the like; acid anhydrides such 
as maleic anhydride, itaconic anhydride, citraconic anhydride, aconitic 
anhydride and the like; .alpha.,.beta.-unsaturated nitriles such as 
acrylonitrile, methacrylonitrile and the like; acrylamide; methacrylamide; 
maleimide; and the like. 
The type of the .alpha.-olefin copolymer is not critical and may be, for 
example, any of random type, block type, graft type and mixed type 
thereof. 
In the thermoplastic elastomer composition of this invention, it is 
necessary that in the .alpha.-olefin copolymer used as the ionomer resin 
(II), at least part of the carboxyl group in the polymer obtained by 
copolymerizing the above .alpha.-olefin, the above 
.alpha.,.beta.-ethylenically unsaturated carboxylic acid and optionally 
said other monomers copolymerizable therewith be neutralized with a metal 
ion. The metal ion includes, for example, ions of alkali metals such as 
lithium, sodium, potassium, rubidium, cesium and the like; ions of 
alkaline earth metals such as calcium, magnesium, strontium, barium and 
the like; and ions of transition metals such as manganese, cobalt, nickel, 
copper, zinc, lead and the like. These metal ions may be used alone or in 
combination of two or more. 
The .alpha.-olefin copolymer having a carboxyl group neutralized with such 
a metal ion can be prepared by allowing the above metal cation to act on 
the base copolymer to ion-crosslink the base copolymer. 
The .alpha.-olefin copolymer used as the ionomer resin (II) is preferably 
one composed of 80 to 99.5 mole of ethylene unit and 20 to 0.5 mole % of 
the .alpha.,.beta.-unsaturated carboxylic acid unit, 10% or more of which 
has been neutralized with a monovalent or divalent metal cation. 
The amount of the ionomer resin (II) contained in the thermoplastic 
elastomer composition is 99 to 1% by weight, preferably 95 to 5% by weight 
and more preferably 90 to 10% by weight. When the amount is more than 99% 
by weight, the flexibility, heat resistance and low-temperature 
characteristics are inferior, and when the amount is less than 1% by 
weight, the excellent characteristics inherent to the ionomer resin 
including mechanical strength, impact resilience and moldability are not 
obtained. 
The polyolefin resin (C) used in the thermoplastic elastomer composition is 
a resin obtained by polymerization of at least one monoolefin by either 
high pressure method or low pressure method, and preferable are 
polyethylene, polypropylene, polybutene-1 and poly-4-methylpentene-1. 
These polyolefin resins may be homopolymers or may also be copolymers of 
the monoolefin with other monomers as shown blow. 
In the polyolefin resin (C), preferable copolymerizing components include, 
for example, straight chain .alpha.-olefins such as ethylene (in other 
cases than the main constituent of the polymer is ethylene), propylene (in 
other cases than the main constituent of the polymer is propylene), 
butene-1 (in other cases than the main constituent of the polymer is 
butene-1), pentene-1, hexene-1, heptene-1, octene-1 and the like; branched 
chain .alpha.-olefins such as 4-methylpentene-1 (in other cases that the 
main constituent of the polymer is 4-methylpentene-1), 2-methylpropene-1, 
3-methylpentene1, 5-methylhexene-1, 4-methylhexene-1, 
4,4-dimethylpentene-1 and the like; unsaturated monocarboxylic acids such 
as acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid and the 
like; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, 
itaconic acid, citraconic acid and the like; monoesters of the 
dicarboxylic acids; acrylic or methacrylic acid esters such as methyl 
methacrylate, methyl acrylate, ethyl acrylate and the like; vinyl esters 
of saturated carboxylic acids such as vinyl acetate, vinyl propionate and 
the like; alkenyl aromatic compounds such as styrene, 
.alpha.-methylstyrene, p-methylstyrene and the like; acid anhydrides such 
as maleic anhydride, itaconic anhydride, citraconic anhydride, aconitic 
anhydride and the like; .alpha.,.beta.-unsaturated nitriles such as 
acrylonitrile, methacrylonitrile and the like; diene monomers such as 
1,4-hexadiene, dicyclopentadiene, ethylidenenorbornene and the like; 
acrylamide; methacrylamide; maleimide; and the like. These copolymerizing 
components may be used alone or in combination of two or more. The type of 
copolymer obtained by copolymerization with them is not critical and may 
be, for example, any of random type, block type, graft type or mixed type 
thereof. The amount of the copolymerizing components contained in the 
copolymer is preferably 20% by weight or less, more preferably 10% by 
weight or less. 
The amount of the polyolefin resin (III) contained in the thermoplastic 
elastomer composition of this invention is 0 to 70% by weight, preferably 
1 to 60% by weight and more preferably 2 to 50% by weight. When the 
polyolefin resin (III) is used in an amount of at least 1% by weight, such 
an effect that the heat resistance and mechanical strength are increased 
is obtained; however, when it is used in an amount of more than 70% by 
weight, the flexibility is lowered. 
The thermoplastic elastomer composition of this invention may if necessary 
be subjected to sulfur-crosslinking, peroxide-crosslinking, metal 
ion-crosslinking, silane-crosslinking, resin-crosslinking and the like by 
a known method. 
The thermoplastic elastomer composition of this invention may comprise, in 
addition to the hydrogenated diene polymer (I), the ionomer resin (II) and 
the optional polyolefin resin (III), an antioxidant, an antistatic agent, 
a weathering agent, a metal-inactivating agent, an ultraviolet absorber, a 
light stabilizer, a slipping agent, a blocking agent, an 
antibleed-blooming agent, a seal-improver, a crystal-nucleating agent, a 
flame retardant, a crosslinking agent, a co-crosslinking agent, a 
vulcanizing agent, a vulcanizing coagent, a bactericide, an antimold, a 
dispersing agent, a tackifier, a softening agent, a plasticizer, a 
viscosity-controlling agent, a color-protecting agent, a defoaming agent, 
a coloring agent such as titanium oxide, carbon black or the like, a metal 
powder such as ferrite or the like; an inorganic fiber such as glass 
fiber, metal fiber or the like; an organic fiber such as carbon fiber, 
aramid fiber or the like; a composite fiber, a glass bead, a glass 
balloon, a glass flake, asbestos, mica, calcium carbonate, an inorganic 
whisker such as potassium titanate whisker or the like; a filler such as 
talc, silica, calcium silicate, kaolin, diatomaceous earth, graphite, 
light stone, ebonite powder, cotton flock, cork powder, barium sulfate, 
fluororesin, polymer beads or the like; a mixture thereof, or other 
rubbery polymers such as SBR, NBR, BR, ETP, EPR, EPDM, NR, IR, 
1,2-polybutadiene, AR, CR or IIR depending upon uses. In addition, the 
composition may comprise appropriately other thermoplastic resins than the 
components (I), (II) and (III), for example, diene resin, polyvinyl 
chloride resin, polyvinyl acetate resin, polycarbonate resin, polyacetal 
resin, polyamide resin, polyester resin, polyether resin, polysulfone, 
polyphenylene sulfide, POM or the like. 
The composition of this invention can be obtained by melt-kneading the 
components (I), (II) and (III) by means of a known kneading machine such 
as an extruder, a kneader, a Banbury mixer or the like, or a kneading 
machine in which these are combined, or dry-blending them by means of an 
injection machine. In the production of the composition of this invention, 
all the components may be mixed at one time or any two of the components 
may be previously premixed, followed by adding and mixing the remaining 
component. Most preferably, the mixing apparatus is a single or twin screw 
extruder and it is possible to thereby continuously and efficiently knead 
the components to obtain a pelletized composition. 
The composition of this invention can be formed into practically useful 
molded articles by a known method such as extrusion molding, injection 
molding, blow molding, compression molding, vacuum molding, slush molding, 
steam molding, laminate molding, calender molding or the like. 
Also, if necessary, the composition of this invention may be subjected to a 
processing such as foaming, powdering, stretching, adhering, printing, 
coating, plating or the like. 
The extrusion molded article obtained using the composition of this 
invention includes sheet, film, tube, profile, special shapes, net, block 
and the like, and can be utilized in various uses. 
The thermoplastic elastomer composition of this invention has essentially 
excellent physical properties of thermoplastic elastomer composition and 
are excellent in transparency, flexibility, mechanical strength, heat 
resistance and moldability. 
The thermoplastic elastomer composition of this invention are materials 
having the above-mentioned excellent characteristics and can be utilized 
in food uses such as food packing sheet or the like; daily sundries uses; 
sports things such as ski boots, other ski things, golf ball coatings, 
core materials and the like; toy uses; stationary uses such as desk mat 
and the like; automotive exterior and interior trim uses such as bumper 
guard and the like; civil engineering and construction uses such as 
engineering sheets, waterproof sheets and the like; domestic appliances 
such as cleaning corner bumper, refrigerator door seal and the like; AV 
apparatus uses, O.A. business apparatus uses, footwear and garment uses 
such as shoe sole, top lift and the like; textile uses; medical apparatus 
uses; chemical and mining industry materials; packaging and transporting 
materials; materials for agricultural industry, livestock industry and 
fisheries; and the like, and hence, is a material having a high commercial 
value. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
This invention is explained in more detail below referring to Examples; 
however, this invention should not be construed to be limited thereto. 
Incidentally, parts and % are by weight unless otherwise specified in the 
Examples and Comparative Examples. 
In the Examples and Comparative Examples, various measurements and 
evaluations were conducted according to the following methods. 
(1) Bound alkenyl aromatic compound content 
Measured by an infrared analysis based on the absorption of phenyl group at 
679 cm.sup.-1. 
(2) Vinyl content in conjugated diene portion 
Calculated by a Hampton method using an infrared analysis. 
(3) Hydrogenation degree 
Calculated from .sup.1 H-NMR spectrum at 100 MHz using ethylene 
tetrachloride as a solvent. 
(4) Number average molecular weight of hydrogenated diene copolymer 
Obtained as a polystyrene-reduced molecular weight, by gel permeation 
chromatography (GPC) at 135.degree. C. using trichlorobenzene as a 
solvent. 
(5) Transparency 
Judged visually using a compression-molded sheet having a thickness of 1 mm 
based on the following criteria: 
.smallcircle.: Transparent 
.DELTA.: Substantially transparent 
x: Translucent 
(6) Flexibility 
Flexural modulus was measured according to JIS K7203 by a three-point 
flexural test. A test specimen having a size of 15 mm.times.60 mm was 
obtained from a compression molded sheet having a thickness of 2 mm. 
(7) Tensile strength 
According to JIS K6301, a No. 3 dumbbell shaped test specimen was prepared 
from a compression-molded sheet having a thickness of 2 mm and a tensile 
strength at break was measured at a drawing speed of 500 mm/min. 
(8) Processability 
A sheet was prepared in a thickness range of 10 .mu.m to 2 mm at a molding 
temperature of 190.degree. C. to 240.degree. C. using a T shaped coat 
hanger manifold dies in a 50-mm.phi. extruder, and the processability was 
evaluated based on the following criteria: 
.smallcircle.: Appearance of molded article had no problem and molding was 
possible under wide processing conditions. 
.DELTA.: Appearance of molded article had no problem, but the processing 
conditions were very much limited. 
x: Appearance of molded article was bad in respects that die line appeared, 
surging was caused and necking was violent, and no improvement was 
possible irrespective of the processing conditions used. 
(9) Impact resilience 
Measured according to JIS K6301. 
(10) Heat resistance 
A ribbon-shaped sample having a size of 4 cm.times.20 cm was cut out of a 
compression-molded sheet having a thickness of 1 mm and formed into a 
cylinder which was used as a sample. The cylinder was stood in a Geer oven 
and allowed to stand at 100.degree. C. for 30 minutes, and heat resistance 
was evaluated from the degree of deformation of the cylinder at that time 
based on the following criteria: 
.smallcircle.: No deformation was found in the cylinder shape. 
.DELTA.: Some deformation was found in the cylinder shape; however, the 
shape before test could be judged. 
x: The cylinder was collapsed and the shape before test could not be judged 
.