U.S. patent application number 11/349980 was filed with the patent office on 2006-06-15 for production of foam webs from high-temperature-resistant polysulfones or polyether sulfones.
Invention is credited to Wolfgang Kratzmuller.
Application Number | 20060125136 11/349980 |
Document ID | / |
Family ID | 7709928 |
Filed Date | 2006-06-15 |
United States Patent
Application |
20060125136 |
Kind Code |
A1 |
Kratzmuller; Wolfgang |
June 15, 2006 |
Production of foam webs from high-temperature-resistant
polysulfones or polyether sulfones
Abstract
The invention relates to a process for producing foam webs by
foam extrusion of a mixture of a polysulfone or polyether sulfone
and a volatile blowing agent, where the blowing agent is water or a
mixture of water with an inert gas or organic liquid, e.g. an
alcohol or a ketone.
Inventors: |
Kratzmuller; Wolfgang;
(Lohfelden, DE) |
Correspondence
Address: |
NOVAK DRUCE DELUCA & QUIGG, LLP
1300 EYE STREET NW
SUITE 400 EAST
WASHINGTON
DC
20005
US
|
Family ID: |
7709928 |
Appl. No.: |
11/349980 |
Filed: |
February 9, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10319642 |
Dec 16, 2002 |
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11349980 |
Feb 9, 2006 |
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Current U.S.
Class: |
264/51 |
Current CPC
Class: |
C08J 2321/00 20130101;
C08J 2203/12 20130101; C08J 2201/03 20130101; C08J 9/149 20130101;
C08J 9/0047 20130101; C08J 2203/10 20130101; C08J 9/125 20130101;
C08J 2203/182 20130101; C08J 9/142 20130101 |
Class at
Publication: |
264/051 |
International
Class: |
B29C 44/20 20060101
B29C044/20 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 20, 2001 |
DE |
10162602.9 |
Claims
1. A process for producing a foam sheet having a thickness of more
than 0.5 cm, said process comprising mixing thermoplastic polymers
selected from polysulfone or polyether sulfone or mixtures thereof
and from 1 to 10% by weight, based on the thermoplastic polymers,
of a volatile blowing agent, at above 300.degree. C. under
pressure, and extruding the mixture into the open atmosphere using
a slot die, wherein the blowing agent is a mixture of water with up
to 200 parts by weight, based on 100 parts by weight of water, of
an alkanol or of an aliphatic ketone.
2. The process of claim 1, wherein the blowing agent is a mixture
of water with up to 100 parts by weight, based on 100 parts by
weight of water, of an alkanol or of an aliphatic ketone with a
boiling point between 50 and 100.degree. C.
3. (canceled)
4. The process of claim 1, wherein acetone is used as ancillary
blowing agent.
5. The process of claim 1, wherein the foam sheet has a thickness
of from 0.5 to 8 cm and a density of from 30 to 100 g/l.
6. The process of claim 1, wherein the foam sheet has a thickness
of from 1 to 8 cm and a density of from 43 to 63 g/l.
Description
[0001] The invention relates to a process for producing foam webs
from a polysulfone or a polyether sulfone by extruding a mixture of
the thermoplastic with from 1 to 10% by weight of a volatile
blowing agent, under pressure into the open atmosphere.
[0002] A process of this type is described in DE-A 4 207 257.
Blowing agents used there are oxygen-containing aliphatic liquids,
such as alcohols, ketones, esters, and ethers, in particular
acetone. However, a problem arising is that the use of these
readily combustible liquids represents a considerable safety risk
at the high temperatures used.
[0003] It is an object of the present invention to eliminate this
risk or at least to reduce it.
[0004] We have found that this object is achieved by using, as
blowing agent, water or a mixture of water with up to 200 parts by
weight, based on 100 parts by weight of water, of an inert gas or
organic liquid as ancillary blowing agent.
[0005] The blowing agent is water or else a mixture with the
following ancillary blowing agents [0006] inert gases, such as
CO.sub.2, nitrogen, argon, [0007] hydrocarbons, such as propane,
butane, pentane, hexane, [0008] aliphatic alcohols, such as
methanol, ethanol, propanol, isopropyl alcohol, butanol, [0009]
aliphatic ketones, such as acetone or methyl ethyl ketone, [0010]
aliphatic esters, such as methyl or ethyl acetate, [0011]
fluorohydrocarbons (e.g. 134a, 152a), [0012] a mixture of
these.
[0013] Particular preference is given to water, and also to
mixtures of water with up to 100 parts by weight, based on 100
parts by weight of water, of an alcohol or of a ketone with a
boiling point between 50 and 100.degree. C.
[0014] The amounts used of the blowing agent are from 1 to 10% by
weight, preferably from 2 to 8% by weight, based on the
thermoplastics. It is possible to add conventional auxiliaries,
e.g. nucleating agents, to regulate the number of cells.
[0015] Surprisingly, it has been found that foam webs of
particularly low density are obtained if the polymer used comprises
a mixture of a high-molecular-weight and a low-molecular-weight
polysulfone or polyether sulfone, preferably in a mixing ratio of
from 5:1 to 1:5. It is preferable here for the flowability MVR
360.degree. C./10 kg to ISO 1133 of the high-molecular-weight
polymer to be below 75 [cm.sup.3/10 min], and that of the
low-molecular-weight polymer to be greater than 80 (cm.sup.3/10
min].
[0016] The process of the invention is preferably carried out on a
plant composed of two extruders. In the first extruder, the
thermoplastic is firstly melted at above its glass transition
temperature, then the blowing agent is injected into the melt under
pressure and homogeneously mixed with the same, whereupon the glass
transition temperature of the mixture falls. In the second
extruder, the mixture is cooled to a temperature at which the
viscosity of the melt is still sufficiently high to form a good
foam. Finally, the mixture is extruded into the open atmosphere,
whereupon it foams. If a slot die is used, the foam sheets obtained
preferably have a thickness of from 0.5 to 8 cm and a density of
from 30 to 100 g/l.
[0017] The proportions of materials mentioned in the example are
percentages by weight.
EXAMPLE 1
[0018] The foam specimens were extruded on a tandem plant. This is
composed of a melting extruder and a cooling extruder.
[0019] A polyether sulfone (ULTRASON 2010 from BASF AG) is fed to
the first extruder. The polymer is melted, and the blowing agent or
the mixture of the blowing agent is injected and then mixed into
the melt, the temperature of which is 340.degree. C. The melt
comprising blowing agent is then cooled in the second extruder to
the temperature needed for foaming (see table). After discharge
from a slot die, the melt foams and is shaped in a calibrator to
give sheets. TABLE-US-00001 H.sub.2O Acetone ST Thickness Density
Experiment (%) (%) (.degree. C.) (mm) (g/l) 1 5 246.5 11 46 2 1 4
249.1 11 43 3 2 3 249.4 10 46 4 2 2 248.7 10 52 5 3 1 248.1 10 63 6
2 243.8 10 82 7 2 247.8 10 124 8 1.5 250.2 10 178
[0020] Experiments 1 and 2 are non-inventive.
EXAMPLE 2
[0021] As described in Example 1, foam sheets were produced from
polyether sulfone. Instead of a single grade, a mixture composed of
a free-flowing, low-viscosity PES (low molecular weight) and a
low-flowability, high-viscosity PES (high molecular weight) was
foamed.
[0022] The materials used are PES E1010, E2010, and E3010 from
BASF.
[0023] The following MFR values describe the flowability of these
materials. TABLE-US-00002 MVR 360.degree. C./10 kg (cm.sup.3/10
min) ISO 1133 E1010 150 E2010 77 E3010 40
[0024] The mixture of grades has broad molecular weight
distribution and can be foamed with water as sole blowing agent to
give lower densities than those given by the individual components.
TABLE-US-00003 E1010 E2010 E3010 H.sub.2O Density (%) (%) (%) (%)
(g/l) 100 3 84 100 3 82 100 3 98 67 33 3 66
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