Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
337 words
A process for preparing an expanded product
of a thermoplastic resin by extrusion molding which
comprises: (I) a gas dissolving step of the thermoplastic
resin at 100 to 450°C in a continuous plasticator
having a line for feeding an blowing agent, and adding
supercritical carbon dioxide and/or nitrogen in a ratio
of 0.1 to 30 parts by weight with respect to 100 parts
by weight of the thermoplastic resin to form a molten
resin composition in which the thermoplastic resin is
compatible with supercritical carbon dioxide and/or
nitrogen, (II) a cooling step of cooling the molten resin
composition to a temperature of 50 to 300°C at a tip
portion of the continuous plasticator, while
maintaining a pressure not less than a critical
pressure of supercritical carbon dioxide and/or
nitrogen, (III) a cell nuclei forming step of discharging
the molten resin composition from a die 4 connected to
the tip portion of the continuous plasticator and set
to a predetermined expansion temperature of the molten resin
composition, whereby the pressure is lowered to a level
not more than the critical pressure of supercritical
carbon dioxide and/or nitrogen to form cell nuclei, and (IV) an expansion controlling step of rapidly
cooling the extruded product of the thermoplastic resin
to a level not more than a glass transition temperature
or a crystallization temperature of the resin to
control a cell diameter of the expanded product,
wherein the die in the step (III) has a flow velocity
distribution adjusting section 13 having a function of
lowering the shear rate on the downstream side of a
shear rate adjusting section 12 having a function of
generating the shear rate of the molten resin
composition (hereinafter referred to simply "the shear
rate") in the range of 10 2 to 10 4 sec -1 ; this shear
rate adjusting section includes a portion of average sectional
area A; and the flow velocity distribution adjusting section
includes a portion of average sectional area B such that B/A
is in the range of 1.3 to 20.
Claim 2
Dependent Claim
32 words
The process for preparing an expanded product
of a thermoplastic resin according to Claim 1 wherein
the die has a function of changing a sectional area of
the shear rate adjusting section.
Claim 3
Dependent Claim
43 words
The process for preparing an expanded product
of a thermoplastic resin according to Claim 1 or Claim 2
wherein a resin pressure at an inlet of the shear rate
adjusting section 12 is in the range of 50 to 400 kg/cm 2 .
Claim 4
Dependent Claim
57 words
The process for preparing an expanded product
of a thermoplastic resin according to Claim 1, 2 or 3 wherein
a ratio C/A between the average sectional area A of the
shear rate adjusting section 12 and a sectional area C
of the obtained expanded product of the thermoplastic
resin is in the range of 2 to 200.
Claim 5
Dependent Claim
25 words
The process for preparing an expanded product
of a thermoplastic resin according to any preceding Claim
wherein the continuous plasticator is a tandem type extruder.
Claim 6
Dependent Claim
24 words
The process for preparing an expanded product
of a thermoplastic resin according to any of Claims 1-4
wherein the continuous plasticator is one extruder.
Claim 7
Dependent Claim
48 words
The process for preparing an expanded product
of a thermoplastic resin according to any preceding Claim
wherein carbon dioxide and/or nitrogen is dissolved in the
thermoplastic resin in a ratio of 2 to 20 parts by
weight with respect to 100 parts by weight of the
thermoplastic resin.
Claim 8
Dependent Claim
33 words
The process for preparing an expanded product
of a thermoplastic resin according to any preceding Claim
wherein molten resin composition further comprises as an
inorganic fine powder and/or an aliphatic carboxylic
acid derivative.
Claim 9
Dependent Claim
22 words
The process for preparing an expanded product
of a thermoplastic resin according to Claim 8 wherein
the inorganic fine powder is talc.
Claim 10
Dependent Claim
27 words
The process for preparing an expanded product
of a thermoplastic resin according to Claim 8 wherein
the aliphatic carboxylic acid derivative is a
derivative of stearic acid.
Claim 11
Dependent Claim
24 words
The process for preparing an expanded product
of a thermoplastic resin according to Claim 10 wherein
the aliphatic carboxylic acid derivative is zinc
stearate.
Claim 12
Dependent Claim
61 words
An extruded expanded product of a
thermoplastic resin prepared by applying shear in a
shear rate adjusting section 12 so that a molten resin
composition may expand wherein an Izod impact strength
of the expanded product is 1.2 to 3 times as much as
that of an expanded product prepared by a die not
having the shear rate adjusting section 12.
Claim 13
Dependent Claim
50 words
An extruded expanded product of a
thermoplastic resin prepared by applying shear in a
shear rate adjusting section 12 so that a molten resin
composition may expand wherein an Izod impact strength
of the expanded product is 1.2 to 3 times as much as
that of an unexpanded test piece.
Claim 14
Dependent Claim
46 words
The extruded expanded product of a
thermoplastic resin according to Claim 12 or 13 wherein
an average cell diameter is in the range of 0.01 to 50
µm, and an average cell density is in the range of 10 8 to 10 16 cells/cm 3 .
Claim 15
Dependent Claim
22 words
Apparatus for carrying out the process of any of
Claims 1-11 comprising a said plasticator (1,3) connected to a
said die (4,11).