Note: Descriptions are shown in the official language in which they were submitted.
3l2~7~
- 1 -
SHAPED ARTICLE OF A STYRENE-BASED POLYMER
l Field of Technoloyy
The present invention relates to a shaped axticlé o a
styrene-based polymer or, more particularly~ to a shaped arti-
cle of a styrene-based polymer having excellent mechanical
strengths and heat resistance.
ack~_ und TechnologY
While styrene-based polymers or, in particular, polystyrenes
hitherto used usually have a stereospecificity of an atactic
structure, such an atactic polystyrene is not crystalli~able
so that the mechanical strengths and heat resistance thereof
are poor and no improvements can be expected in the physical
properties thereof even by drawing. Besides, a polystyrene hav-
ing a stereospecificity of an isotactic structure is also known
and a proposal has been made of a shaped article of the same
with drawing [Kobunshi Kagaku, volume 21, page 206 (1964~3~
Such an isotactic polystyrene, however, has a low velocity of
crystallization and the crystalline structure thereof has a
spiral configuration so that the effect to be obtairled by draw-
ing cannot be fully exhibited.
The inventors have been successful in developing a styrene-
based polymer having a high syndiotacticity [see Japanese Patent
Kokai 62-104818]~
The present invention has an object to develop a shaped
article having excellent properties such as mechanical strengths,
heat resistance and the like by using the above mentioned novel
~ 374~ ~
- 2 -
1 styrene-based polymer of a syndiotactic structure as the base
material.
Disclosure of the Invention
~ Namely, the present invention provides a shaped article
of a styrene-based polymer prepared by drawing a styrene~based
polymer having a mainly syndiotactic structure and a weiyht~
average molecular weight o~ at lea~t 100,000.
The shaped article of a styrene-based polymer is shaped
of a styrene-based polymer having at least 85% of the syndio-
tacticity in the racemic pentad by the nuclear magnetic reso-
nance spectrometric analysis with the carbon isotope as the
particular material and is excellent in the mechanical strengths
such as elastic modulus, impact strength and the like and heat
resistance.
Best Mode to Practice the Invention
The base material of the shaped article of the present
invention has a mainly syndiotactic structure or, in other words,
a steric structure in which the phenyl groups or substituted
phenyl groups as the pendant groups are directed alternately
to the reverse directions relative to the main chain formed
of carbon-to-carbon linkages. The tacticiky thereof can be quan-
titatively determined by the nuclear magnetic resonance method
with a carbon isotope (13C-NMR method).
The tacticity determined by the 13C-NMR method can be ex-
pressed by the proport.ion of an uninterrupted sequence of aplural number of the structural units such as the diad for the
sequence of two units, triad for the sequence of three units
and pentad for the sequence of five units. The styrene-based
~2~374~
- 3
1 polymer having a mainly syndiokactic structure as lmplied in
the present invention should include polystyrenes, poly(alky~
styrenes), poly(halogenated styrenes), poly(alkoxy styrene~),
poly(benzoic ester styrenes) and mixtures thereof a~ well ~s
copolymers mainly composed thereo~ having a syndiotactlalty
of, usually, at lea~t 85~ or, pref~rablyt at lea8~ 9S~ o~ the
pentad, i.e. racemic pentad. The poly(alkyl styrenes) are exem-
plified by poly(methyl styrenes), poly(ethyl styrenes), poly(iso-
propyl styrenes), poly(tert-butyl styrenes) and the like, and
the poly(halogenated styrenes) are exemplified by poly(chloro
styrenes), poly(bromo styrenes) and the like. The poly(alkoxy
styrenes) are exemplified by poly(methoxy styrenes), poly(ethoxy
styrenes) and the like.
Although, as is described above, the styrene-based polymer
used in the present invention should usually have at least 85~
of the syndiotacticity in the racemic pentad, a quite satisfac-
tory tensile modulus can be exhibited even with a somewhat lower
value thereof by suitably selecting the conditions of the draw-
ing treatment. When the syndiotacticity of a styrene~based poly-
mer is too low, however, full improv~ment cannot be expected
in the tensile modulus by the drawing treatment.
Besides, the styrene-based polymer used in the present
invention should have a weight-average molecular weight of,
desirably, at least 100,000 or, preferably, in particular, at
least 300,000~ When the weight-average molecular weight thereof
is smaller than 100,000, no satisfactory strength and elastic
modulus can be obtained. The polymer can be used without limita-
tion by the molecular weight distribution which may be broad
~ 2 ~4~ ~ I
-- I
1 or narr~w.
According to the present invention, a shaped article ha~i~g
excellent physical proper~ies can be obtained by subjeating the
above described styrene-based polymer to a drawing treatment.
The drawing treatment here may be performed either b~ ~he
uniaxial drawing or by the biaxial drawing. 1'hough not par-
ticularly limitative, the dr~winy ratio should pre:eerably he
at least 200~ in the uniaxial drawing and at least 150% in each
direction in the biaxial drawing while a drawing ratio of 300
to 500~ gives the best result in each case. The temperature
in the drawing treatment should desirably be a temperature some-
what higher than the glass transition temperature of the styrene-
based polymer. The starting sheet material subjected to the
drawing treatment should preferably have a thickness of about
50 to 500 ~m as obtained by extrusion or calendering. The melt
molding by which the starting sheet mat~rial is molded should
be carried out at a temperature by about 20C higher than the
melting point of the styrene-based resin. The drawing treatment
of the sheet material obtained by the melt molding should be
performed at a temperature a little higher than the glass
transition temperature of the resin.
The drawing treatment carried out in this manner is fol-
lowed, if desired, by a thermal fixing treatment. In this case,
the film after drawing is thermally fixed in a tensioned condi-
tion at a temperature in the range between the melting pointand a temperature higher than the glass transition temperature
by about 70C. This thermal fixing treatment has an effect to
increase the heat resistance and dimensional stability of the
film as drawn.
~ll2~4~l
., _ 5
l Further, shaping of fibers as drawn can be undertaken under
the same conditions as described above. In addition to such
a melting drawing, wet drawing and gel drawing can also he under-
taken.
When the wet drawing or yel drawing should be pex~ormed,
usable solvenks include benzene, toluene, xyl~ne, ~thyl ben~ne,
cyclohexane, Decalin, N-methyl pyrrolidone r tetrahydrofuran,
carbon tetrachloride, chloroform, dichloro methane, monochloro
benzene, dichloro benzene, trichloro benzene, Trichlene and
the like. Further, the drawing treatment may optionally be per-
formed of a styrene-based polymer having a syndiotactic struc-
ture admixed with a styrene-based polymer having an atactic
structure, a styrene-based polymer having an isotactic struc-
ture or a styrene-based polymer o~ a low molecular weight having
a syndiotactic structure and further with a suitable amount
of an antistatic agent, lubricant, anti-fogging agent, heat
stabil.izer, dye, pigment, metal powder and inorganic fine powder
such as talc~ mica and the like.
In the following, the present invention is described in
more detail by way of examples and comparative examples.
Example 1.
(1) Preparation of a styrene-based polymer
Into a reaction vessel were introduced 20 ml of toluene
as a solvent, 0.05 m mole of tetraethoxy titanium and 5 m moles as
aluminum atoms of methyl aluminoxane as the catalytic ingredients and then
150 ml of styrene were added thereto at 40 C to conduct the
polymerization reaction for 4 hours. After completion of the
reaction, the product was washed with a liquid mixture of methyl
12~7461
alcohol and hydrochloric acid to decompose and remove the cata-
lytic ingredients. Subsequent drying gave 2S g of a s~yrene-based
polymer, i.e. polystyrene. This polymer was then subjected to
ex~raction in a Soxhlet extractor using methyl ethyl ketone
as the solvent to obtain 95% by weight of the unextracted matte~,
which is referred to as MIP hereinbelow. This material had a
weight-average molecular weight of 1,350,000,~number-average
molecular weight of 480,000 and melting point of 270 C. The
13C-NMR analysis indicated an absorption at 145.35 ppm assignable
to the syndiotactic structure and the syndiotacticity in the
racemic pentad was 96% as calculated from the area of the ab-
sorption peak.
t2) Preparation of a shaped article ¦l
The styrene-based polymer having a syndiotactic structure I
obtained in (1) described above was extruded out of an extrusion
molding machine and shaped into a strand. This strand was sub-
jected to a drawing treatment in a drawing ratio of 300% in ! !
an oil bath kept at 130 UC followed by cooling to room tempera-
ture without releasing the tension The thus obtained strand
after drawing had a tensile modulus of 150~000 kg/cmZ.
Example 2.
In the same manner as in (1) of Example 1, a polystyrene
having a weight-average molecular weight of B00,000 and a syndio-
tacticity of 96% was compounded with each 0.1% by weight of
bis(2,4-di-tert-butyl phenyl) pentaerithritol diphosphite and
tetrakis[methylene(3,5-di-tert_butyl-4-hydroxy cinnamate)] meth-
ane as the antioxidants and pelletized by extrusion out of a
double-screw extruder of 40 mm diameter.
::,, ~,.................. :
37~
-- 7 -
l The pellets were fed to a sinyle~screw extruder o~ 40 mm
diameter equipped with a T-die at the front end and extruded
to give a sheet of 600 ~m thickness under the condition~ of
the temperature of the cylinder at 290 C, t~mperature of th~
T-die at 300 C and rate of extrusion of 4.2 kg/hour. The cool-
ing roller of the ~heet was kept at 55 C.
The thus obtained transparent sheet had a density of 1.08
g/cm3 and a glass transition temperature of 101 C. The sheet
was subjected to a uniaxial drawing treatment at 108 C to give
a film as drawn in a drawing ratio of 450%. This film was sub-
jected to a thermal fixing treatment at 190 C and 210 C eachfor 20 seconds under tension.
The physical properties of the thus obtained uniaxially
drawn film are shown in Table 1.
Examples 3 and 4.
The transparent sheet obtained in Example 2 was biaxially
drawn in 200~ or 400% in both of the drawing directions~ These
biaxially drawn films were subjected to a thermal fixing treat-
ment under tension at 210 C for 20 seconds. The thus obtained
biaxially drawn films are shown in Table 1. Incidetally, the
drawn film before the thermal fixing after 400% drawing in eachof the length-wise and transverse directions had an elongation
at break of 50~ showing a gxeat improvement over the undrawn
sheet having an elongation at break of 2%.
Comparative Example 1.
Table 1 shows the physical properties determined of the
undrawn sheet obtained in Example 2.
Example 5.
, , ~- ,.
12~74~L
l A polystyrene having a weight-average molecular weight
of 1,500,000 and syndiotacticity o~ 96~ obtained ln the same
manner as in (1) of Example 1 was compounded with a ~ine powder
o~ talc to give a content of 2% by weight and then shaped into
a sheet at 280 C using a calendering roller~ Thereafter, the
sheet was subjected to 350~ drawing in the length~wise dlrec~ion
at 115 C and then 250~ drawing in the transverse direction
at 118 C. Further, a thermal fixing treatment thereof was under-
taken at 213 C for 2~ seconds. Table 1 shows the physical prop-
erties of the thus obtained biaxially drawn film.
Comparative Example 2.
Table 1 shows the physical properties of the undrawn sheet
obtained in Example 5.
Example 6.
~1) Preparation of a styrene-based polymer
A styrene~based polymer was prepared in just the same manner
as in (1) of Example 1.
(2) Preparation of a shaped article
The styrene based polymer obtained in (1) described above
was put into ethyl benzene as a solvent and dissolved with heat-
ing to give a solution of the styrene-based polym~r in a con-
centration of 2% by weight. This solution was poured into a
well chilled aluminum-made box to give an agar-like gel. This
gel was freed from the liquid by suction on a Buchner funnel
under pressing and then dried at room temperature for 24 hours
under reduced pressure to give a gel plate. In the next place,
this gel plate was cut into a strip which was subjected to draw-
ing at 130 C in air in a drawing ratio of 800%. The thus obtained
~l~f~7~
_ g _
l material as drawn was subjected to the measurement o mech~nlcal
strengths. Th~ results are shown in Table 2
Example 7.
~1) Preparation of a styrene-based polymer
The same procedure as in (1) of Example 1 was undertaken
except that the polymerization ternperature was set at, 5 C ~o
give 2.8 g of a styrene-based polymer, i.e. polystyrene. The
MIP thereof was 94% by weight. The thus obtained styrene-based
polymer (MIP) had a weight-average molecular weight of 500f 000
number-average molecular weight of 180,000 and syndiotacticity
of 95%.
(2~ Preparation of a shaped article
The same procedure as in (2) of Example 6 was undertaken
excepting the use of the styrene-based polymer obtained in (1)
described above. The results are shown in Table 2.
Example 8.
(1) Preparation of a styrene-based polymer
The same procedure as in (1) of Example 1 was undertaken
except that the polymerization temperature was set at 30 C
to give 9.0 g of a styrene-based polymer, i.e. polystyrene.
The MIP thereof was 99~ by weight. The thus obtained styrene-
based polymer (MIP) had a weight-average mole~ular weight of
1,800,000, number-average molecular weight of 650,000 and syndio-
tacticity of 98%.
(2) Preparation of a shaped article
The same procedure as in (2) of Example 6 was undertaken
except that the styrene-based polymer ohtained in (1) described
above was used and the drawing ratio was 700~. The results are
~lZ~3~
- 10 - l
,
l shown in Table 2.
Example 9. !
(1) Preparation of a styrene-based polymer
The same procedure as in t1) of Example 1 was undertaken
5 except that the polymerization temperature was set at 20 C
to ~ive 4~0 g of a styrene-based polymer, i.e. poly~yrene.
The M~P thereof was 92% by weight. The thus obtained styrene~
based polymer (MIP) had a weight-average molecular weight of
2,400,000, number-average molecular weight of 860,GQQ and syndio-
tacticity of 100~.
(2) Preparation of a shaped article
The same procedure as in (2) of Example 6 was undertaken
except that the styrene-based polymer obtained in (1) described
above was used and the drawing ratio was 600~. The results are
shown in Table 2.
Example 10.
11) Preparation of a styrene-based polymer
The same procedure as in (1) of Example 1 was undertaken
excepting the polymerization temperature at 0 C and polymeriza-
tion time of 8 hours to give 1.5 g of a styrene-based polymer,
i.e. polystyrene. The MIP thereof was 70% by weight. The thus
obtained styrene-based polymer (MIP) had a weight-average molecu-
lar weight of 4,500,000, number~average molecular weight of
1,600,000 and syndiotacticity of 100~.
(2) Preparation of a shaped article
The same procedure as in (2) of Example 6 was undertaken
except that the styrene-based polymer ob~ained in (1) described
above was used and the drawing ratio was 500%. The results are
.
~2~374~i~
-- 11 --
1 shown in Table 2.
Comparative Example 3.
The same procedure as in (2) of Example 6 was undertaken
excepting omission of the drawing treatment. The results are
shown in Table 2.
Comparative Example 4.
10.0 y of magnesium dietoxide were r~acted with 50 rnl o~
tetrachloro titanium to prepare a titanium compound, The
mixture of 1.0 m mole of titanium catalytic ingredients sup-
porting the above obtained titanium compound and 10 m mole oftriethyl aluminum was used as the catalyst. Polymerization
reaction of 100 ml styrene was conducted for 2 hours at 70C
in heptane as a solvent to give 48.7 g of styrene-based
polymer i.e. polystyrene, having isotactic structure and
weight-average molecular weight of 1,000,000, number-average
molecular weight of 260,000. This styrene-based polymer had
the unextracted matter of 96% by weight, extracted by using
methyl ethyl ketone by the same procedure as in (2) of the
Example 1. The above obtained styrene-based polymer having
the isotactic structure was subjected to drawing in the same
manner as in (2) of the Example 1 (drawing ratio of 600%).
The thus obtained material as drawn was subjected to the
measurement of the mechanical strengths. The results are
shown in Table 2.
Comparative Example 5.
The same procedure as in Comparative Example 4 was under-
taken excepting omission of the drawing treatment. The resul~s
are shown in Table 2.
4~
- 12 -
Example 11.
(1) Preparation of a styrene-based polymer
Into a reaction vessel were introduced 20 ml of toluene
as a solvent and 0.0445 m mole of tetraethoxy titanium and 4.45
m moles as aluminum a~oms of methyl aluminoxane as ~he c~ lyti~
ingredients and then 110 ml o~ styrene were add~d there~,o at
20C to conduct the polymerization reaction for 7 hours. After
completion of the reaction, the product was washed with a liquid
mixture of hydrochloric acid and methy~ alcohol to decompose
and remove the catalytic ingredients. Subsequent drying gave
1.7 g of a styrene-based polymer, i.e. polystyrene. The MIP
thereof was 98% by weight. The thu.s obtained styrene-based poly-
mer had a weight-average molecular weight of 3,040,000, number-
average molecular weight of 1,220,000 and syndiotacticity of
99%.
(2) Preparation of a shaped article
The styrene-based polymer obtained in (1) described above
was put into p-xylene as a solvent and dissolved with heating
to give a 1% by weight solution of the styrene-based polymer.
This solution was poured into a flat dish to give a rigid agar-
like gel. This gel was washed with acetone and a gel mat was
obtained by compression. This gel mat was cut into a strip which
was dried at room temperature for 10 hours under reduced pressure.
This strip was subjected to drawing in a drawing ratio of 700%
by the solid-phase coextrusion at 150C in air together with
poly(4-methyl pentene-l). The thus obtained material as drawn
was subjected to the measurement of the mechanlcal strengths.
The results are shown in Table 2.
374~
- 13 -
1 Example 12.
(1) Preparation of a styrene-based polymer
A styrene-based polymer was prepared in just ~he same manner
as in (1) of Example 11.
(2) Preparation of a shaped article
The styrene-ba~d polymer obtained ln ~1) de~c~rib~d abc)v~
was put into chlorof'orm as a solvent and dissolved with heating
to give a solution of the styrene-based polymer in a concentra
tion of 0.1% by weight. This solution was poured into a well
chilled copper-made box to give an agar-like soft gel. This
gel was freed from the liquid by suction on a Buchner funnel
with compression and then dried at room temperature for 10 hours
under reduced pressure to give a gel plate. In the next place,
this gel plate was cut into a strip which was subjected to a
1~ drawing treatment in a drawing ratio of 700~ at 150C in air
by the solid-phase coextrusion together with poly(4-methyl pen-
tene-l). Table 2 shows the mechanical strengths of the thus
obtained material as drawn.
Example 13.
(1) Preparation of a styrene-based polymer
The same procedure as in (1) of Example 11 was undertaken
excepting the polymerization temperature at 50C and the poly-
merization time of 80 minutes to give 2.2 g of a styrene-based
polymer. The MIP thereof was 97% by weight. The thus obtained
styrene-based polymer had a weight-average molecular weight
of 940,000, number-average molecular weight of 380,000 and
syndiotacticity of 97%.
J v ^
14 -
1 (2) Preparation of a shaped article
A film by casting was prepared from the styrene-based pol~-
mer obtained in (1) described above using chloro~orm as the
solvent. This cast film was cut into a strip which was subjected
to drawing in the same manner as in (2) of Example 11 to yive
a material as drawn in a drawing ratio of 700~. rr~bl~ 2 shows
the mechanical strengths of the khus obtained material as drawn.
Example 14.
(1) The method for the preparation of a styrene-based polymer
Into a reaction vessel were introduced 1~0 ml of toluene
as a solvent and 0.15 m mole of tetraethoxy titanium and 15
m moles as alumin~m atoms of methyl aluminoxane as the cata-
lytic ingredients and then a mixture of 145 m moles of styrene
and 15 m moles of p-methyl styrene was added thereto at 30C
to conduct the polymerization reaction or 2 hours. After com-
pletion of the reaction, the product was washed with a liquid
mixture of hydrochloric acid and methyl alcohol to decompose
and remove the catalytic ingredients. Subsequent drying gave
Z2 g of a styrene-based polymer. In the next place, this polymer
was subjected to extraction in a Soxhlet extractor with methyl
ethyl ketone as the solvent to give 9.9% by weight of the un-
extracted matter. This material had a weight-average molecular
weight of 960,000, number-average molecular weight of 460,000
and melting point o 225C. The content of the p-methyl styrene
moiety therein was 23% by moles and absorption bands were found
in the analysis by the 13C-NMR at 145.11 ppm, 145.22 ppm and
142.09 ppm indicating a co-syndiotactic structure similarly
to the copolymer described in the specification of Japanese
~2~
- 15 -
l Patent Application 62-017973.
(2) Preparation of a shaped article
A gel plate was prepared in the same manner as in (2) of
Example 12 excepting the use of the styrene-based polymer ob-
tained in (1) described above and use of p-xylene as ~he
solvent and a drawn mate.rial in a drawi.ncJ ratlo o~ 700'~ was
obtained by drawing the same. Table 2 shows the mechanical
strengths of the thus obtained material as drawn.
~2~7a~6~l
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- 18 -
1 Possibility o~ Industrial Utilization
Shaped articles or, in particular, shaped articles such
as fibers, films, tapes ~nd the like according to the present
invention have greatly improved mechanical strengths or, in
particular, elastic modulus imparted by a drawing ~rea~ment
while maintaining the heat re.slstance as an inherent property
o~ a styrene-based polymer having a syndiotactic structure~
Accordingly, the shaped articles of a styrene-based polymer
of the pr~sent invention can be widely and efficiently utilized
in various applications including ropes, cables, composite re-
inforced materials and so on.
