Note: Descriptions are shown in the official language in which they were submitted.
`\
Multi-ply vessel and method for production thereof
The present invention relates to multi-ply vessels
: having good gas barrier properties and high transparency,
and a method for the production thereof.
Thermoplastic polyester resins, mainly polyethylene
terephthalate, have widely been used for various vessels
and packaging materials in the form of films and sheets
~ ; because of their excellent mechanical properties, gas
:: ~ barrier properties, chemical resistance, scent mainten-
ance and hygienic qualities. In particular, with the
10: progress made in blow-molding techniques, especially
biaxial orientation blow-molding techniques, these
resins are now frequently employed for the production
of hollow vessels~, such as bottles and cans. For ex-
ample~, thermoplastic polyester bottles produced by a
~;:: :: 15 biaxial orientation blow-molding technique are disclosed
in United States Pa~tent No. 3,733,309.
However, the vessels produced from thermoplastic
: polyester resins, mainly polyethylene terephthalate, by
: : such biaxial orientation techniques are not satisfactory
:
.
~'t
-- 2
for all applications. For example, these vessels are
not suitable for packaging food whlch require strict iso-
lation from the atmosphere because they have poor gas
barrier properties against oxygen.
Known thermoplastic resins having high gas barrier
properties include saponified e~hylene-vinyl acetate
copolymers r styrene-acrylonitrile copolymers and the
like but the vessels made from these resins alone are
in~erior in impact resistance or are not favorable from
the hygienic viewpoint and, hence, can not be used in
practice.
In Japanese Patent Laid Open Publication No.
108162/1978, it is disclosed that a vessel having gas
barrier properties can be produced by orienta~ing and
blow-molding a vessel preform (hereinafter referred to
;,
~ as a parison) having a two-layer structure composed of
i
a thermoplastic polyester resin and a saponified ethylene-
vinyl acetate copolymer. However, when a saponified
ethylene-vinyl acetate copolymer is used, the parison
becomes opaque during formation thereof because the co-
polymer itself lS a crystalline resin. Of course, if
he parison is designed and oriented to produce thin
walls, the transparency thereof is somewhat improved,
but the non-orientated parts, such as the bottom part
. ~ : :
25 of a~bottle, are still opaque, which results in an over-
all poor appearance.
:
,,.~,,,;. ~,
7~
-- 3 --
When a ~ulti-ply vessel is produced by using a styrene-
acrylonitrile copolymer, which is a resin known to have
high gas barrier properties, together with a thermoplastic
polyester resin, the parison does not lose ~ransparency
during formation thereof because the copolymer itself is
a non-crystalline resin. However, the copolymer has a
high glass transition temperature and7 hencel the parison
can not be sufficiently orientated at an orienting tem-
perature suitable for the polyester resin. Moreover,
because of the non-crystalliæability of the copolymer, no
crystalli~ation of the copolymer is induced by orientation
and, thereby, the vessel may be unfavorably deformed by
; orientation release stress.
An object of the pres~nt invention is to provide a
vessel combining gas barrier properties against oxygen
and the desirable properties of a thermoplastic polyester
resin, e.g. good mechanical properties, transparency,
chemical resistance, hygienic qualities and the like.
According to one aspect of the invention there is
provided a multi-ply vessel having a multi-ply structure
composed of at least two kinds of synthetic resins which
comprises an inner layer composed of a thermoplastic
polyester resin having an intrinsic viscosity of 0.55 or
more, a middle layer composed of a metaxylylene group-
containing polyamide resin and a moisture impermeable
~: , , ' ` '
i'7'~ -
outer layer composed of a synthetic resin, said layers of
the thermoplastic polyester resin and the metaxylylene
group-containing polyamide resin being oriented in at
least one direction at thin parts of ~he vessel wall.
According to another aspect of the invention there is
provided a process for production of a multi-ply vessel
which comprises forming a multi ply parison having a
multi ply structure of an inner layer composed of a
thermoplastic polyester resin having an intrinsic
viscosity of 0.55 or more, a middle layer composed of
a metaxylylene group-containing polyamide resin and a
moisture impermeable outer layer composed of a thermo-
plastic synthetic resin, and then orientating the multi-
ply parison thus-formed in a draw ration of 1 to 4 times
in the longitudinal direction and of 2 to 7 times in the
crosswise direction at a temperature of from Tg + 15C to
2(Tg) ~ 15C, wherein Tg is a glass transition temperature
of the thermoplastic polyester resin.
An advantage of the present invention, at least in the
preferred forms, is that it can provide a vessel having
good dimensional stability and form retention, and g~od
adhesion between the layers of the multi-ply structure
thereof.
A conventional fiber-forming polyester resin can be
; 25 used as the thermoplastic polyester resin which composes
; :~
~ ~ I
. ~
- 4a -
the inner layer of the vessel of the present invention.
Polyesters having repeating units consisting predominantly
of ethylene terephthalate are preferable. However, poly-
esters such as polycyclohexane dimethylene terephthalate
can also be used.
,
?
`
-- 5 --
Suitable thermoplastic polyester resins having
repeating units consisting predominantly of ethylene
terephthalate include polyesters consisting of acid
components comprising 80 mol% or more, preferably 90
mol% or more, of terephthalic acid and glycol compon-
ents comprising 80 mol% or more, preferably 90 mol% or
more, of ethylene glycol. The acid components other than
terephthalic acid may be selected Erom isophthalic acid,
diphenyl ether-4,4'-dicarboxylic acid, naphthalene-1,4-
or 2,6-dicarboxylic acid, adipic acid, sebacic acid~
decane~l,10-dicarboxylic acid, hexahydroterephthalic
acid and the like; and the glycol components other than
ethylene glycol may be selected from propylene glycol,
1,4-butanediol, neopentyl glycol, diethylene glycol,
cyclohexane dimethanol, 2,2-bis(4-hydroxyphenyl)-propane,
; 2,2-bis(4-hydroxyethoxyphenyl)propane and the like. The
~ thermoplastic polyester resin may also contain an oxy-acid
i
; component e.g. p-hydroxybenzoic acid, p-hydroxyethoxy-
;~ ~ benzoic acid and the like. The thermoplastic polyester
:
resin may be used as a blend of two or more polyester
~ ~ resins, provided the content of ethylene terephthalate
; ~ ~ is in the range mentioned above.
: The thermoplastic polyester resin used in the present
invention may optionally contain an appropriate amount
of an additive e.g. a colorant, ultraviolet absorber,
antistatic agent, agent for pre~enting deterioration of
,~
.
-- 6 --
properties due to heat and oxidation, anti-microbial
agent, lubricant and the like.
The intrinsic viscosity of the thermoplastic polyester
resin should preferably be 0.55 or more, more preferably
0.65 to 1.4. When the polyester resin has an intrinsic
viscosity of less than 0.55, the vessel preform, i.e.
the parison, is difficult to obtain in the transparent
amorphous state and, further, the vessel obtained may
have poor mechanical properties.
The metaxylylene group-containing polyamide resin
(hereinafter referred to as an SM resin) which composes
; the middle layer of ~he vessel o ~he present invention
is a polymer containing, in the molecular chain thereof,
at least 70 mol% of a unit which consists of metaxylylene-
diamine or a mixed xylylenediamine of metaxylylenediamine
~- and 80 % by wéight or less of paraxylylenediamine based on
:
the mixture, and an ~,~-aliphatic dicarboxylic acid having
6 to 12 carbon atoms.
Examples of the metaxylylene group-containing
poIyamide resin are a homopolymer e.g. polymetaxylylene-
; ~ adipamide, polymetaxylylenesebacamide, polymetaxylylene-
suberramide; a copolymer e.g. metaxylylene/paraxylylene-
adipamide copolymer, metaxylylene/paraxylylene-impelamide
copolymer, metaxylylene/paraxylylene-azeramide copolymer;
; 25 and a copolymer of the monomers composing the above homo-
polymer or copolymer and other copolymerizable monomers
e.g. aliphatic diamines (e.g. hexamethylenediamine),
~ ::
; ~ .
,
'7~
alicyclic diamines (e.g~ piperazine), aromatic diamines
(e.g. para-bis(2 aminoethyl)benzene), aromatic dicar-
boxylic acids (e.g. terephthalic acid), lactams (e~g.
~-caprolactam), ~-aminocarboxylic acids (e.g. y-amino-
heptanoic acid), aromatic aminocarboxylic acids (e.g.p-aminomethylbenzoic acid) and the like. To improve
the impact resistance at low temperature and adhesion,
it is preferable ~o copolymerize, during the polymer-
ization of the polyamide resin, 0.2 to 10 % by weight
based on the polyamide resin of a polyalkylene ether
compound having at least one amino group or carboxyl
group and having a molecular weight of 2,000 to 20,000,
preferably 3,000 to 8,000, Eor example, bis(aminopropyl)~
poly(ethylene oxide), bis(aminopropyl)-poly(butylene
oxide) or the like. In ~he above copolymer, the content
of paraxylylenediamine in the total xylylenediamines
is 80% by weight or less and the content of the unit
consisting of the xylylenediamines and the aliphatic
dicarboxylic acid in the molecular chain of the copolymer
is at least 70 mol%. ~he polymers may optionally inlcude
a small amount of other polymers e.g. nylon-6, nylon-6,6,
nylon-6,10, nylon-ll, nylon-12 and the like and other
additives e.g~ antistatic agents, lubricants, an~i-
blocking agents, stabilizers, dyestuffs, pigments and
the like.
SM resin is intrinsically brittle in the amorphous
,
;7
-- 8 --
state, and, hence, it should have preferably a relative
viscosity of 1.5 or more, more preferably 2.0 or more.
Generally, a vessel is produced by forming a vessel
preform, i.e. a mul~i-ply parisonl and then orientating
and blow-molding the parison. In order to obtain a vessel
having good gas barrier properties and high transparency,
the multi ply parison should also have good transparency
and further the resin components at the thin parts of the
vessel wall (mainly the body thereof) should be at least
uniaxially orientated. Hence, the parison should be also
at least uniaxially orientated to produce such a vessel.
The outer layer of moisture-impermeable synthetic
resin can be formed as an outer layer of a multi-ply
parison or can be formed on the S~ resin layer after
orientation and blow-molding of the parison, e.g., as
-- a surface finishing of the SM resin layer, by coating
the SM resin layer with a film, by topcoating which is
employed in certain kinds of glass and bottles, by spray
coating and the like. Preferably, the outer layer is
formed as that of a multi-ply parison and then the parison
orientated and blow-molded to produce the vessel.
~ xamples of the compounds or the synthetic resins
used for the above finishing, topcoating or spray coating
methods are an unsaturated monomer consisting predominant-
,:
; 25 ly of an unsaturated silane, a polymer of an unsaturated
monomer consisting predominantly of an unsaturated silane,
. .
'
'
_ 9 _
an epoxy silane compound, an alkoxy silane compound, anorganic titanium compound, a silicone resin, a fluoro-
plastic, polyvinyl chloride, polyvinylidene chloride and
the like. The formation of the outer layer employing
these resins improves impermeability to moisture and
prevents changes of the gas barrier properties with time.
Of course, when the orientation and blow-molding are dif-
ficult to carry out because of the formation of the outer
layer, the layer should be formed after the orientation
and the blow-molding.
The synthetic resin used for the outer layer formed on
the multi-ply parison is a thermoplastic resin which does
not prevent the orientation and blow-molding of the thermo-
plastic polyester resin of the inner layer. Examples of
the resin are the same kind of the thermoplastic polyester
resin used for the inner layer9 polyvinyl chloride, poly-
propylene, and a copolymer consisting predominantly of
an acrylonitrile component containing 80 mol% or less of
acrylonitrile and an unsaturated monomer e.g. styrene,
ethyl acrylate and methyl acrylate.
Thermoplastic polyester resins, particularly those
having repeating units consisting predominantly of
ethylene terephthalate and having an intrinsic viscosity
of 0.55 or more, are preferred in view o the transparency
and other desirable properties of the resulting vessel as
well as possible recovery and reuse of the ve~sel. The
.
'5
- 10 -
~e~in may optionally contain additivest e.g. lubricants,
anti-blocking agents, stabilizers, colorants, agents Eor
providing metallic sheen and the like.
A typical method for the production of the multi-ply
vessel of the present invention is given below.
The vessel can be produced by forming a multi-ply
parison and orientating and blow-molding the parison
according to a conventional method. Particularly, the
vessel can be conveniently produced by a biaxial orien-
10 tation blow-molding technique at a specific temperature.
When the vessel is produced by a biaxial orientation
blow-molding technique, a multi ply parison is heated to
an orientation temperature and then expanded and orien-
tated by a rod which moves axially in a metal mold and
lS compressed air is blown into the mold to form the vessel.
The multi-ply parison can be produced by successively
forming the multi-ply structure from the inner layer with
a conventional injection molding machine or a molding
machine having equipment for melting and injecting several
20 materials, or by providing a bottom in a pipe having a
multi~ply structure formed by a multi-ply extrusion
molding machine.
The shape of the multi-ply parison is not critical
25 provided it is in a geometric form which can be expanded.
When the~multi-ply parison is injection molded, the mold
t~mperature should be kept low. In particulrr, when the
,
~`7'~
middle and outer layers are formed, it is preferable to
keep the temperature lower than that employed in the
formation of the inner layer. When the middle and outer
layers are formed, the mold temperature is usually below
30C, preferably 5 to 20C.
In order to maintain the mold temperature in the above
range, it is preferable to pass a fluid, e.g. tap water or
chilled water, through the inside of the mold.
When the a~ove molding technique i5 carried out, a
multi~ply parison having good transparency can be obtained.
Moreover, one of the characteristics of the present inven-
tion is that the adhesion between the layers of the vessel
produced by expanding and orientating the multi-ply parison
is superior to that of a vessel produced by orientating a
partially opaque multi-ply parison.
Each resin layer of the parison is generally 0.1 to
5 mm, preferably 1 to 3 mm, in thickness and the total
thickness of the inner, middle and outer layers is
generally 1 to 8 mmr preferably 2 to 6 mm. If each layer
of the parison is less than 0.1 mm in thickness, the resin
to be used for the layer hardly flows in the mold. If
the total thickness of the layers is more than 8 mm, the
multi-ply parison becomes opaque during the formation of
; the middle and outer layers thereof, or an extremely high
blowing pressure is necessitated. In comparison with
injection molding, when the multi-ply parison is produced
' ;:
.
.
7~5
- 12 -
by multi-ply extruslon molding, each resin layer can be
formed as thin as several tens of microns, if desired.
However, in order to retain the shape of the vessel after
biaxial orientation blow-molding, each resin layer should
generally be about 0.1 to 4 mm in thickness. Of course,
when a parison consisting only of the inner and middle
layer is prepared by extrusion molding and then the outer
layer is formed on the parison by surface treatment or
surface coating, the thickness of the outer layer may be
10 much thinner.
The multi-ply parison thus obtained is heated to a
orientating temperature and then expanded and orientated
-~ in a blow-mold to produce a hiaxially orientated vessel.
The orientation temperature is from (Tg ~ 15)C to
15 ~2Tg + 15~C, preferably 90 to 150C, wherein Tg means
the glass transition temperature of the polyester resin.
This is based on the fact that the glass transition
temperatures of the metaxylylene group-containing poly-
~;~ amide resin are close to those of the polyester resins.
20 When the parison is heated to the above temperature range,expansion and orientation can be carried out without any
problem.
It is not desirable that the preheating temperature be
lower than (Tg ~ 15)C since microvoids are formed in the
25 vessel due to cold orien~a~ion and the resulting vessel
has a pearly appearance which makes it opaque. Likewise,
~' ' ~ ' , `
:` .
7~
- 13 -
it is not desirable that the preheating temperature be
higher than (2Tg + 15)C, since the polyester resin of the
outer layer then becomes opaque due to crystallization
thereof and adhesion between the resin layers is Leduced.
A draw ratio of 1 to 4 times in the longitudinal direction
and of 2 to 7 times in the crosswise direction is neces-
sary for expanding and orientating the multi-ply parison.
In view of the adhesion between the layers, e.g. between
the outer layer and the middle layer or between the middle
1~ layer and the inner layer, as well as the transparency of
the vessel, an area draw ratio (draw ratio in longitudinal
- direction x draw ratio in crosswise direction) of 5 to 18
times is preferable.
Although SM resin itself is intrinsically a crystal-
15 line resin, the glass transition temperature thereo is
relatively high and it readily takes on an amorphous
form when the molten resin is quenched, to give a parison
having good transparency. Additionally, since the glass
transision temperature of the SM resin is almost equal to
20 that of the polyester resin, it is sufficiently orientated
:
and crystallized under orientation conditions for the
polyester resin. Thus, in contrast to other known resins
;~ having high gas barrier properties, a vessel having high
transparency as well as good gas barrier properties and
25 heat stability and, therefore, having high commercial
value, can be obtained.
~:~
,~ ' . .
s
- 14 -
The degree of orientation can be determined by meas-
uring the difference between the refractive index in the
cross sectional direction and that in the plan direction
of a thin part of the vessel wall. In order to obtain
good gas barrier properties and high transparency, the
difference between the refractive i~dexes is desirably
0.02 or more, preferably, 0.03 or more, more preferably~
0.05 or more. When the difference between the refractive
indexes is less than 0.02, the mechanical properties and
lO gas barrier properties may be insufficiently improved and,
further, the adhesion between the layers is reduced.
When the measure~.ent of a refractive index is diffi-
cult, the degree of orientation can also be determined
based on anisotropy of mechanical properties and the like.
In the multi-ply vessel of the present invention, the
;~ middle layer of SM resin is generally 5~ to l mm, prefer-
ably, lO~ to 500~ in thickness. The inner resin layer and
the outer resin layer are generally 50~ to 1 mm, preferably
100~ to 500~ in thickness, respectively. In practice, the
20 total thickness of the inner, middle and outer layers is
100~ to 2 mm, preferably, 200~ to l mm. Further, the ratio
of the thickness of the polyester resin inner layer to that
of SM resin middle layer is l or less. Even i~ this ratio
becomes more than l, no Eurther improvement in the gas
25 barrier properties can be expected, but rather, defects
are produced such as an increase in the orientating stress
~'~
~ . .
- . , : ' ' , :
" "' ' ~ :
-- .
. - , .
. . . .
2~5
- 15 -
during blow-molding and the like.
The description hereinbefore refers to a process for
the production of a multi-ply vessel having inner and
outer layers both made of polyester resin and having a
middle layer of SM resinO Optionally, the vessel of the
present invention can also be produced by forming adhe-
sive layers between the middle and the outer layers and/or
between the middle and the inner layers. When the area
draw ratio is 5 times or less, the adhesion between the
10 polyes~er resin and SM resin is insufficient and hence,
it is preferable to provide an adhesive layer. Further,
when polyvinyl chloride or the like is substituted for
the polyester resin of the outer layer, a vessel of the
present invention can be produced under the above con-
15 ditions. However~ when the outer layer is formed by
~- finishing of the surface oE SM resin layer or topcoating,
the thickness of the outer layer may be much thinner.
:
~; ExampIes o~ an adhesive for improving the ply separa-
tion resistance are a copolyester resin, a copolyamide
20 resin, an ~-olefin vinyl ester copolymer, a modified
olefin resin containing carbonyl groupr a urethane
modified copolyester resin or the like, the melting or
softening temperature of which is about 200C or less,
; preferably, 70 to 200C. Optionally, these resins may
25 be further copolymerized with an ingredient containing
a small amount of an acid metallic salt group.
,
.
- 16 -
If the moisture permeation resistance of the synthetic
resin outer layer is insufficient, a treatment for improv-
ing the moisture permeation resistance can be effected on
the surface of the outer layer or an additional layer can
be provided on the outer layer.
Although the description so far has referred to a
multi-ply vessel (bottle) produced by orientating and
blow-molding a multi-ply parison and the method there-
for, the present invention is not limited thereto. For
10 examplef the multi-ply vessel of the present invention
includes a can produced by orientating and blow-molding
a multi-ply cylinder to expand the cylinder, optionally
thermosetting the cylinder, cutting the cylinder in an
appropriate length and then sealing at least one end
15 thereof with a sealing plate of a metal or a plastic,
,~ or a vessel produced by deep-drawing a laminate sheet.
The following examples further illustrate the present
invention.
The methods of measurement of main characteristics
20 determined in the present invention are as follows:
(1) Intrinsic viscosity [~] of the polyester resin: It
was measured at 30C by using the mixed solvent of phenol-
tetrachloroethane (6 : 4, w/w).
(2) Relative viscosity [nrel] of the polyamide resin: It
25 was measured at 25C by dissolving the resin (1 g) in 96
~sulfuric acid l100 ml).
.,
:
~,
.
' :
`
- 17 -
(3) Glass transition temperature (Tg): It was measured at
a heat-up rate of ~0C/min by using Differential Scanning
Colorimeter manufactured by Perkin Elmer (DSC - lB~.
(4) Melting point (Tm): It was measured by the same
manner as in Tg.
(5) Refractive index: It was measured at 25C by using
Abbe refractometer equipped with a polarising plate and
using ~he D-line of a sodium lamp. A specimen (1.5 cm
square) was cut off from a thin part of the body of the
10 multi-ply vessel obtained and the refractive indexes
thereof in ax;al and peripheral directions were measured.
The degree of orientation was determined by calculating
the birefringence of the specimen as follows:
Birefringence ~n) = -~ 2 ny -nz
15 in which nx and ny are refractive indexes in the axial
'L,. and peripheral directions (plane direction), respectively,
and nz i5 refractive index of the specimen in the cross-
sectional direction.
(6~ Transparency and haze: I~aze meter-S manufactured by
20 Toyo Seiki was used and according to JIS - K6714, these
were calculated as follows:
Transparency = (T2/Tl) x 100 (%~
T4 - T3-(T2/Tl)
Haze = - - x 100 (%)
~: in which Tl is an amount of incident light, T2 is a
25 total amount of transmitted light, T3 is an amount of
.
...
,:
'~
~ f'~
- 13 -
light scattered by the device and T4 is an arnount oflight scattered by the device and the specimen.
(7) Amount of oxygen permeation: It was determined
according to ASTM-D-1434-58 by measuring pressure the
change at 30C with a twin gas transmission measuring
instrumen~ manufactured by Rika Seiki Kogyo (cc/m2.24
hr. atm).
(8) ~mount of moisture permeation: It was determined
according to JIS-Z~0208 by measuring the weight gain at
10 40C under 90 % RH by cup method ~g/m2.24 hr).
(9) Tensile characteristics: Yield strength, tensile
elongation at break and tensile ~trength at break oE a
specimen strip of 10 mm in width were measured at 23C,
50 mm/min of strain rate by using a Tensilon (Trade Mark)
15 manufactured by Toyo Bowldwin having 50 mm of distance
- between the chucks.
Examples 1 and 2 and Reference Example 1
A multi-ply parison having an outer diameter of 35 mm,
a length of 140 mm and a thickness of 5 mm was formed by
20 using a polyethylene terephthalate (hereinafter referred
to as PET) of [n] = 0.72, Tm = 257C and Tg = 70C as the
polyester resin of the inner and outer layers thereof and
a polymetaxylylene-adipamide (metaxylylenediamine : para-
xylylerlediamlne = 99 : 1, w/w) of nrel = 2.2, Tm = 37C
25 and Tg = 75C (hereinaEter referred to as S~-l) in
Example 1 or SM-l compolymerized with 2.5 % by weight of
: ~,
~7~ ~
,9
polyethylene glycol diamine having a molecular weight of
4000 of nrel = 2.35, Tm = 235C and Tg = 73C (hereinafter
referred to as SM-2) in Example 2 as the metaxylylene
group-containing polyamide resin of the middle layer
S thereof. In Reference Example 1, a parison of the same
shape as in Examples 1 and 2 was formed by using a poly-
ethylene terephthalate of [~] = 0~72.
The formation of the multi-ply parison was carried out
by forming the inner parison of the polyester resin of 2 mm
10 in thickness and laminating the SM resin middle layer, and
then the polyester resin outer layer on the inner parison
while successively changing the metal molds ~o obtain the
` multi-ply parison. Thickness of each layer of the parison
was inner layer : middle layer : outer layer = 2 mm : 1.5
15 mm : 1~5 mm.
~The molding was carried out by using an N-95 (Trade
; ~Mark) injection machine manufactured by Nippon Seikosho
under the conditions shown in Table 1.
::
: ~ :
, ~
,~
:`
~ , :
'
"
~ . .
7~
- 20 -
Table 1
Inner Middle ¦ Outer
layer layer I l~yer
(PET) (SM) , (~ET)
Cylinder temperature
(C, from hopper270x290x290260x280x280 i 270x290x290
side) g
. . ..
Inject~on pressure i 40 .
10 (kg/cm gauge) ~ 50 60
i
Mold temperature (C)~, 20 ¦ 15 1 12
In ection pressure ! 15 15 ¦ 15
! i
: Cooling tlme (sec) ¦ 25 25 ¦ 25
~::
The open end of the parison thus obtained was fitted
into a parison fitting part having a rotary drive and ~he
parison was heated and rotated in an oven having a far
infrared heater until the surface temperature of the
parison rose to 110C. After heating, the parison was
transferred into a blow~mold and blow-molded at a travel
~:~ : rate of an orientating rod of 22 cm/sec under a compressed
gas pressure of 20 kg/cm2 to obtain a hollow vessel in
:
a beer bottle shape of 265 mm in length, 80 mm in outer
: diameter of the body and 1000 ml in internal space. The
: 25 properties of the vessel thus ob~ained are shown in
Table 2.
~ ~ .
`~ :
.
,1
~ 21 -
Table 2
jExample 1 ~Example 2 iReference~
¦ j IExample 1
Transparency (%) I 87 ¦ 86 ~ 89
IHaze (%) '2.0 ; 6.5 j 1.3
'
¦Amoun~ of oxygen permeation ~ '. .
. ~ (cc/m .24 hr~atm) !1.5 1.7 14
Amou~t of moisture permeation . i
~(g/m .24 hr) 0.6 . 0.6 , 0.5
!Birefringence (~) O.058 'O.053 ,O.068
_ _ ~
Yield strength (kg/cm2) , 972 ~ 824 1 1068
i
¦Tensil~ strength at break ' .
''(kg/cm ) 1417 `, 1212 1 1542
:, '. . i I
--~ !
'Tensil elongation at break
i(%) 180 86 76
I Note: Ail the specimens used were cut off from the main
body portions.
As is clear from the results of Table 2, the vessels
,
of Examples 1 and 2 have remarkably improved oxygen barrier
properties without any deterioration of transparency and
mechanical properties in comparison with the vessel of the
polyethylene terephthalate alone.
.
.
~6~Z~
~ 22 -
Examples 3 to 6 and Reference Examples 2 to 4
Various parisons were formed by using the PET in
Example l as the polyester resin oE the inner and outer
layers thereof and the SM-l as the metaxylylene group-
containing polyamide resin of the middle layer thereof.In each case, the thickness of each layer of the parison
was inner layer : middle layer : outer layer = 2 mm :
1.5 mm : 1.5 mm. The molding of the parison was carried
out by using an N-95 (Trade Mark) injection machine manu-
10 factured by Nippon Seikosho and biaxial orientation blowmolding was effected by using a molding machine in Katata
Laboratories of Toyo Boseki manufactured by way of experi-
ment~ Each hollow vessel thus obtained had a beer bottle
shape of 265 mm in length, 80 mm in outer diameter of the
15 body and 1000 ml in internal space (Examples 3 to 6 and
Reference ~xamples 2 and 3) or of 200 mm in leng-th, 80 mm
in outer diameter of the body and 700 ml in internal space
(Reference Example 4). The molding conditions in each
Example are shown in Table 3 and properties of the vessel
~ 20 thus obtained are shown in Table 4.
:~
*~
:
~ ~ ~j7~
-- 23 --
~ ~, ~ _____ ~ _~ .__ _ .
~ h O N O
X ~ ~
_ h
.~ ~ ~
. - ~; W . h
. N O q)
p;X ~ ~
O O O .~ .~
_ ~ CO ~
N /~ N ~ ~
1~ X X X ~ 5-1
`' ~ O O O O O O ~
W ~ OD O~ ~ Ul ~ ~ ~
~; . N N N
X X ~1 h .
o o o ~ ~::
~, 1~ ~ 1~ .~ ~1
N N N ~1 ~1 O O O
X 1~1 If ) ~ N ~1
_ ~ ,~ , .~ _ .. ~ ____~ .~ _ _ __. _~ . _.~ _
u~ h h ~1 S~ ~ s l ~,~ 5~ h ~1 ~1 C~ s I ~ ~ h s I ~
~: ~1 aJ ~ O O ~ a~ o ~ a) a) a) u~ ~q O a) ~ a) o o
:~ ~ ~ O ~ :~ O ~>~ ~ ~ ~ ~ ~ :~ ~ ~ Ul _.
O ~ H ~1 ~ ~1 0 ~1H ~1 ~ 0 ~1 S~ au H H ~ ~ 0 ~1
~ ~ ~^ ~ .
~: ~ ~ C~ ~ ~ Q) ~ Q~
O ~ ~ o O ~ ~ O u~
,: ~ ~ O aJ--~ _ ,1 ~ .,1 _ ~ Q~
; ~ ~u~ ~1 ~ ~ ~ o 5~ o
~l ~ ~ o u~ t) r~l
: ~: ~ ~ ~ O ra ~ ~ a) ~1 ~1 ~1
O Q~ n a) ~ ~ r~ a~ O ~10
Q. ~ a) s~ o ~ s~ ~ :1 ~ 3 O O o .
O ~ U JJ ~ ~ H Q~ H ~ C) ~ ~
_ ~ O _
~: : ~ ~'
~ ~ '
~ '
: :
~ 24 --
__ . . .,_._ _ .~
" ~ U~ o Ul o,
~ ~ E~ ~ ~u~ ~ ~ _ ~ ~ ~ X
~J ~ 4J ~J ~ . O h ~ ~ ~ h ~ t~5
~: ~ Q .~ 0~) ~ E-l ~ ~ O ~ ~ O O 1
O ~ ~ h ~,_ a
o o ~ ~ ~: ~ V U~ ~ ~ ~
u7 O ~1 0 ~1 IJ ~ a) ~ ~ h
tJ~ ~I U~ 0 ~1 a) ~ ~ ~:
~ ~ ~ ~ . ~ ~ ~ ~ E~ a) -,~ 3
~ ~ _ ~ o ~ ,~_ m E~ o c~ ~ ~ ~
~ e~
.
-- 25 --
._ ~
~r ~ ~ ___ _____ __ _ .
p~ X CO N t~l O O Ct~ r-l ~
_ _ _ _ '''I
~D 0~ ~r L~ ~ ~9 ~ ~
. c~ . . . a~ ~ ~ ~r
0~ ~ ~ O O 0
O
_ __ _ _
~ CO 0~ ~ CO ~ 00
~ ~ O ~ ~ ~ ~ ~ ~ ~
X ~ r~ ~ o o I
O
_ __ __ ~ ~_ _~ ~_ __
4~ ~~ ~
~ ~ ~ ~3
P;
O 0
C~
m _ ___ ___ n N ~_1 ~1
~C CO ~r-iO O CO (~I ~1
~ O ~
_ _.. _ __ . __ __ __ .____ __
' .
.. ~ O Irl ~D co N 1~ O
.~ . . . In I~ ~1 ~
~~o ~ ~ o o ~ ~r
O
`.
_ _ __
:
~ ~1 ~r u~ co ~ ~ co
:: ~ ~ ~ ~ ~i O O ~ ~ ~
___ . ___ _ __
. .
: ~ ~ ~ ~ ~
: ~ ~ ~ ~ ~ - a ~ O
~: ~ a) ~ ~ _
a~ ~ ~ ~~n ~ ~ ~) ~
~ ~ ,~ a ~ Z:n ~ nJ
Q :~ X ~ O ~ O t~ ~:: tn t~--
0 o o ~ ~ s~ ~ ~ a
~ ~ ~ ~ ~ ~ a) ~, O -~
: ~ a~ ~ o ~r ~ o t~ ~ ~ ,,
; ~ _ o ,~ ~ o ,~ ~ ~ ~ ~ u~ ~ a~
: ~ ~ o\o ~ ~ ~ ,~ u~ r~
~: , Q. _ ~ ~'O ~d . S~ ~ ~1 a) ~1 a
u~ ~ ~ ~ ~ o ~ ,~ ~
:: : ~ ~ ~ F~ \~ ; ~ ~ ~ Ul Q U~ Q
:: ~ N O ~1 OO S~ ~ 1-l O t7~ ~: ~::
5~ ~ ~ a) o~ a) tl~ ,~ -rI ~: O ~ a~
_ _ p~ ~-~C ~ ~ m _~ _
~:
~:
~ ' '
' "' ':
~ .
~ 7
- 26 -
As is clear from the results of Tables 3 and 4, all
the vessels of the present invention obtained in Examples
3 to 6 have high transparency as well as excellent gas
barrier properties and mechanical properties.
In contrast, in ~eference Example 2, the orientation
temperature is too low and hence, an extremely high-stress
is needed in orientation. As a result, the parison may be
broken in the orientating and blowing step or can not be
shaped to the desired form, or, even if the parison can
10 be shaped, the bottle is unsuitable in practice since the
appearance thereof becomes extremely pearly. In Reference
Example 3, the orientation temperature is too high and the
parison becomes opaque due to crystalli2ation of the sur-
face layer thereof in the heating step. Moreover, there
;~ 15 are some defects, Eor example, insufficient mechanical
properties such as drop impact strength and the llke due
to an insufficient orientation e~fect.
Further, in Reference Example 4, the area draw ratio
is 5 times or less and hence, adhesion between the resin
20 layers is insufficient which resulks in ply separation by
drop impact. If the area draw ratio is small, the problem
of ply separation can be solved by providing an adhesive
layer between the polyester layer and SM resin layer. An
improvement of the mechanical properties due to improved
~5 adhcsion is also expected by providing the adhesive layer.
.,~ . '
- 27 -
Examples 7 to 10 and Reference Examples 5 to 7
-
Hollow vessels were obtained by the same procedure as
in Examples 3 to 6 and Reference Examples 2 to 4 except
that SM-2 was used as the metaxylylene group-containing
5 polyamide resin of the middle layer. Further, the molding
conditions employed in Examples 7 to 10 and Reference
Examples S to 7 corresponded to those in Examples 3 to
6 and reference Examples 2 to 4 as shown in Table 3.
The properties of the vessels thus obtained are shown
lOin Table 5.
.
'
~ 7~
- 28 -
~1 ~ __. ~o o o n ~ o
_ ___ .. _ _ ~ ~_ _ ~
X co ~ ,~ o o co
1:~ O ~1 N
___ _ __ __ ~_~ __ _
~D ~ CO O ~D L~ ~
P~ ~r o~) ~l o Ol ci) o N
O
_ . __~_ . _ , ,,.,~ _~_ ~ ~ ~.~
. ~n a
~; X
o o~
o ~ m
_ _ _.___ __ . ___ _ ~
~ ~ CO ~D ~' ~ ~ t`
. ~D . . . Ln ~ ~ C~
X c~~D ~ O O CO
o ~
--__ ___, _ .__ .~ _ ~__ .
-~ o~ Ln t~~ ~ ~ N ~D
:, ~ . ~ . . . In ~ ~ ~
X 0~ ~7 ~ O O 00
:' _ _____ _
''
r- r~ o~ ~D ~ U~ O ~ ~
~X co ~ ~--i o o N Cl:)
_ _ _ .. _ ~ _~_~. ,~,. ~w ~ ~_
m _~ ~ ~ a N^ O
a) 0~0 ~ ~ ~ _ ~ ~ ~ .~
. ,1 a~ ~ ~ ~
: ~ x ~ ~ a ~ u ~ h-- O
a) 4~ o ~r 4~ o t~ h ~ ~
h _ O -rl N O rl ~ ~ ~ ^ L~ X a) X
L~ 0~ ~, ~ L~ ~ L~ ~L rd
~ _ ~ ~ ~ ~ . h ~ ~ ~ ~i a
u~ 5:~ o ~ 1~ ~:1 u ~I h ,1 h
~ ~ ~ E~ \ ~ ~ E3 a) ~ ~ ,~ ,~ ,~ ,~
N O h U O h ~ S~ a) ~ ~ ~::
_ E~ X ~ ~ ~ ~ ~ a: ~ ~ E~, E~ ~
~ _ ~ ~._ ~
:
~ .
..
:
'7~
- 29 -
As is clear from the results of Table 5, Examples 7 to
10 and Reference Examples 5 to 7 showed the same results
as those in Examples 3 to 6 and Reference Examples 2 to 4,
respectively. That is, vessels having high transparency
5 as well as excellent gas barrier properties and mechanical
properties were obtained in Examples 7 to 10. However,
in Reference Examples 5 to 7, a vessel having sufficient
commercial value as in the present invention could not be
obtained. Further, the vessel obtained according to the
10 present invention had excellent dimensional stability and
form retention.
Example 11
By using PET and SM-1 as in Example 1, a two-layer
parison without an outer layer (PET layer = 3.5 mm in
; ~ 15 thickness, SM-1 layer - 1.5 mm in thickness) was formed
under the same conditions as in Example 3. After applying
a coat of a polyvinyl chloride resin on the outer surface
of the parison, a vessel was produced by orientating and
; blow-molding the parison under the same conditions as in
Example 3. As a result, a vessel having 85 % of trans-
parency, 2.2 % of haze, 1.3 cc/m~.24 hr atm of oxygen
:::
~; permeation and 0.6 g/m2.24 hr of moisture permeation,
;;~ that isr having excellent transparency and gas barrier
properties was obtained, The vessel had a yield strength
of 1195 kg/cm2 and a tensile strength of 1820 kg/cm2.
~ ~ .
