U.S. patent application number 14/108519 was filed with the patent office on 2014-04-17 for process for manufacturing a surface-treated compacted material processable on a single screw plastics conversion equipment.
The applicant listed for this patent is Ernst Ammann, Peter Haldemann, Emil Hersche, Michael Knerr. Invention is credited to Ernst Ammann, Peter Haldemann, Emil Hersche, Michael Knerr.
Application Number | 20140107259 14/108519 |
Document ID | / |
Family ID | 41050582 |
Filed Date | 2014-04-17 |
United States Patent
Application |
20140107259 |
Kind Code |
A1 |
Ammann; Ernst ; et
al. |
April 17, 2014 |
PROCESS FOR MANUFACTURING A SURFACE-TREATED COMPACTED MATERIAL
PROCESSABLE ON A SINGLE SCREW PLASTICS CONVERSION EQUIPMENT
Abstract
The present invention relates to the field of processing
thermoplastic polymers, particularly the present invention relates
to a process for manufacturing compacted material suitable for the
use in thermoplastic polymers without a compounding step,
comprising the steps of a) providing at least one primary powder
material; b) providing at least one molten surface treatment
polymer; c) simultaneously or subsequently feeding the at least one
primary powder material and the at least one molten surface
treatment polymer into the high speed mixer unit of a cylindrical
treatment chamber; d) mixing the at least one primary powder
material and the at least one molten surface treatment polymer in
the high speed mixer, e) transferring the mixed material obtained
from step d) to a cooling unit, as well as the compacted material
obtained by this process and its use in thermoplastic polymers.
Inventors: |
Ammann; Ernst; (Muhlethal,
CH) ; Knerr; Michael; (Oftringen, CH) ;
Haldemann; Peter; (Rothrist, CH) ; Hersche; Emil;
(Wollerau, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ammann; Ernst
Knerr; Michael
Haldemann; Peter
Hersche; Emil |
Muhlethal
Oftringen
Rothrist
Wollerau |
|
CH
CH
CH
CH |
|
|
Family ID: |
41050582 |
Appl. No.: |
14/108519 |
Filed: |
December 17, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13378911 |
Dec 16, 2011 |
|
|
|
PCT/IB2010/052810 |
Jun 22, 2010 |
|
|
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14108519 |
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61269882 |
Jun 30, 2009 |
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Current U.S.
Class: |
524/13 ; 524/175;
524/427; 524/432; 524/436; 524/52; 524/570; 524/577; 524/584 |
Current CPC
Class: |
C08K 3/34 20130101; C09C
1/021 20130101; C08K 3/18 20130101; C08K 5/56 20130101; B29B 9/12
20130101; C01P 2004/61 20130101; C01P 2004/03 20130101; C08K 3/22
20130101; C08L 97/02 20130101; C08K 9/04 20130101; C01P 2006/12
20130101; C09C 3/10 20130101; C08J 3/223 20130101; B29K 2105/16
20130101; C08J 3/22 20130101; C08J 3/20 20130101; C08L 3/04
20130101 |
Class at
Publication: |
524/13 ; 524/570;
524/584; 524/577; 524/427; 524/436; 524/52; 524/432; 524/175 |
International
Class: |
C08K 3/18 20060101
C08K003/18; C08K 3/22 20060101 C08K003/22; C08K 5/56 20060101
C08K005/56; C08K 3/34 20060101 C08K003/34 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 23, 2009 |
EP |
09163509.4 |
Claims
1. A process for manufacturing a thermoplastic polymer comprising
introducing a surface-treated compacted material into a
thermoplastic polymer, wherein the surface-treated compacted
material is obtained by a process comprising the following steps:
a) providing at least one primary powder material; b) providing at
least one molten surface treatment polymer; c) simultaneously or
subsequently feeding the at least one primary powder material and
the at least one molten surface treatment polymer into the high
speed mixer unit of a cylindrical treatment chamber; d) mixing the
at least one primary powder material and the at least one molten
surface treatment polymer in the high speed mixer; and e)
transferring the mixed material obtained from step d) to a cooling
unit.
2. A thermoplastic polymer comprising a surface-treated compacted
material, wherein the surface-treated compacted material is
obtained by a process comprising the following steps: a) providing
at least one primary powder material; b) providing at least one
molten surface treatment polymer; c) simultaneously or subsequently
feeding the at least one primary powder material and the at least
one molten surface treatment polymer into the high speed mixer unit
of a cylindrical treatment chamber; d) mixing the at least one
primary powder material and the at least one molten surface
treatment polymer in the high speed mixer; and e) transferring the
mixed material obtained from step d) to a cooling unit.
3. The thermoplastic polymer according to claim 2, wherein at least
one surface treatment agent is fed simultaneously with or after the
feeding of the at least one primary powder material into the high
speed mixer unit of a cylindrical treatment chamber.
4. The thermoplastic polymer according to claim 2, wherein before
step e) the mixed material obtained from step d) is transferred to
a second mixing unit.
5. The thermoplastic polymer according to claim 2, wherein the at
least one molten surface treatment polymer is added to and mixed
with the mixed material of step d) in the second mixing unit.
6. The thermoplastic polymer according to claim 2, wherein the
temperature of the primary powder material is between 20.degree. C.
and 300.degree. C.
7. The thermoplastic polymer according to claim 2, wherein the
temperature of the primary powder material is between 60.degree. C.
and 250.degree. C.
8. The thermoplastic polymer according to claim 3, wherein the
temperature of the surface treatment agent is between 20.degree. C.
and 300.degree. C.
9. The thermoplastic polymer according to claim 3, wherein the
temperature of the surface treatment agent is between 60.degree. C.
and 250.degree. C.
10. The surface-treated compacted material according to claim 3,
wherein the temperature of the surface treatment agent is between
60.degree. C. and 120.degree. C.
11. The thermoplastic polymer according to claim 2, wherein the
primary powder material is an inorganic powder.
12. The thermoplastic polymer according to claim 11, wherein the
inorganic powder is natural ground calcium carbonate (GCC),
precipitated calcium carbonate (PCC), a calcium
carbonate-containing mineral, dolomite, a mixed carbonate based
filler; a mineral containing calcium associated with magnesium,
mica, talc, clay or any mixture thereof; mica, talc, a talc-calcium
carbonate, a calcium carbonate-kaolin mixture; a mixture of natural
ground calcium carbonate with aluminium hydroxide, mica or with
synthetic or natural fibres; or a co-structure of minerals, a
talc-calcium carbonate co-structure, or a talc-titanium dioxide
co-structure.
13. The thermoplastic polymer according to claim 11, wherein the
inorganic powder is natural ground calcium carbonate (GCC),
precipitated calcium carbonate (PCC), or a mixture of GCC and PCC,
or a mixture of GCC and PCC and clay, or a mixture of GCC and PCC
and talc, or talc, or mica.
14. The thermoplastic polymer according to claim 11, wherein the
inorganic powder is ground calcium carbonate (GCC) selected from
marble, chalk, calcite and limestone.
15. The thermoplastic polymer according to claim 11, wherein the
inorganic powder is precipitated calcium carbonate (PCC) selected
from aragonitic PCC, vateritic PCC, calcitic PCC, rhombohedral PCC,
scalenohedral PCC, or any mixture thereof.
16. The thermoplastic polymer according to claim 2, wherein the
primary powder material is an organic powder.
17. The thermoplastic polymer according to claim 16, wherein the
organic powder is wood flour or modified starch.
18. The thermoplastic polymer according to claim 2, wherein the
molten surface treatment polymer is an ethylene copolymer, an
ethylene-1-octene copolymer, a metallocene based polypropylene, a
polypropylene homopolymer, or an amorphous polypropylene
homopolymer.
19. The thermoplastic polymer according to claim 3, wherein the
surface treatment agent is stearic acid, zinc oxide, a synthetic
paraffin wax, a polyethylene metallocene wax or a polypropylene
wax.
20. The thermoplastic polymer according to claim 2, wherein the
surface-treated compacted material is processable on a single-screw
plastics conversion equipment.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a divisional of U.S. application Ser. No.
13/378,911, filed Dec. 16, 2011, which is a U.S. national phase of
PCT Application No. PCT/IB2010/052810, filed Jun. 22, 2010, which
claims priority to European Application No. 09163509.4, filed Jun.
23, 2009 and U.S. Provisional Application No. 61/269,882, filed
Jun. 30, 2009, the entirety of which are hereby incorporated by
reference.
[0002] The present invention relates to the field of processing
thermoplastic polymers, particularly the present invention relates
to a process for manufacturing compacted material suitable for the
use in thermoplastic polymers without a compounding step, as well
as the compacted material obtained by this process and its use in
thermoplastic polymers.
[0003] Compounding consists in preparing plastic formulations, by
mixing or/and blending polymers and additives in a molten state.
There are different critical criteria to achieve a homogenous blend
of the different raw material. Dispersive and the distributive
mixing as well as heat are important factors. Co-Kneaders and twin
screws (co- and counter rotating) as well internal mixers are the
most common used compounder in the plastic industries.
[0004] For decades, the thermoplastic processing industry uses
additives for preparing modified thermoplastic resin compositions,
which are to a great extent introduced into the polymer resins via
compounding technologies requiring the formation of intermediate
products named masterbatches/concentrates or compounds.
[0005] For example, WO 95/17441 discloses a method of preparing a
thermoplastic resin end-product comprising the preparation of
thermoplastic granules for blending them with the thermoplastic
resin.
[0006] In WO 01/58988, a method for preparing masterbatches or
concentrates of mineral fillers to achieve highly filled
thermoplastic materials are described.
[0007] However, according to these documents, it is not possible to
obtain a polymeric end-product having the primary powder compounds
well dispersed in a conventional single screw extruder. Rather, it
is required to produce an intermediate product like a masterbatch,
or concentrate, i.e. it is not possible to disperse fine primary
powders on conventional single screw machines without intermediate
compounding step.
[0008] In this respect, further documents such as WO 2007/066362
describe a mixing process and device with only one material inlet,
while others like EP 1 156 918, WO 2005/108045 or WO 2005/065067
relate to extruders or element mixers.
[0009] However, there is still a need for an easy and effective way
of manufacturing additives from primary powders, which are suitable
to be introduced in thermoplastic polymers without the need of any
intermediate steps.
[0010] Accordingly, it is a first object of the present invention
to provide a process for manufacturing materials suitable for being
incorporated in thermoplastic polymers by a continuous or
discontinuous process, wherein the primary powder material to be
introduced into the thermoplastic polymer can be well dispersed in
a conventional single screw extruder.
[0011] This object is achieved by the process according to the
present invention, namely a process for manufacturing a compacted
material characterised in that it comprises the following steps:
[0012] a) providing at least one primary powder material; [0013] b)
providing at least one molten surface treatment polymer; [0014] c)
simultaneously or subsequently feeding the at least one primary
powder material and the at least one molten surface treatment
polymer into the high speed mixer unit of a cylindrical treatment
chamber; [0015] d) mixing the at least one primary powder material
and the at least one molten surface treatment polymer in the high
speed mixer, [0016] e) transferring the mixed material obtained
from step d) to a cooling unit.
[0017] Without being bound by any theory, the Applicant believes
that it is possible for the compacted material to be well dispersed
in the thermoplastic polymer, i.e. without the formation of any
agglomerates, using conventional single screw extrusion equipment
due to the combination of two factors, namely the use of high speed
mixers combined with the use of surface treatment polymers which
are able to form thin layers around the singularised particles of
the primary powder which totally cover the particles surfaces
resulting in a surface-treated compacted material. The singularized
and coated particles may then form loose conglomerates, but are
still separated by the polymeric surface layers. This is the
desired step of compaction. The result of the compaction is an
increase in bulk density, an improvement of the flowability and the
suppression of dust as described in more detail below.
[0018] Well dispersed means that dispersions, which are visually
tested on pressed film under a binocular magnifier with
magnification of 50 of each of the dispersions made, show no black
spots corresponding to the matrix polymers nor white spots
corresponding to the primary powders.
[0019] By compacted material, a bulk material is understood to
consist of a conglomerate of a number of single particles forming a
material with a mean particle size ranging from 10 .mu.m to 10 mm
measured by sieve analysis using the Retsch AS 200 sieve tower
according to ISO 3310 standard.
[0020] In a preferred embodiment, a further surface treatment
agent, preferably at least one surface treatment agent is fed
simultaneously with or after the feeding of the at least one
primary powder product into the high speed mixer unit of a
cylindrical treatment chamber. The surface treatment agent
preferably is liquid or liquefied, especially it is provided in the
molten state.
[0021] The main difference between the surface treatment agent and
the surface treatment polymer is that the surface treatment agents
are chemically bound to the primary powder. Preferably, they serve,
inter alia, to alter the surface tension of the powder and thus the
hydrophobicity thereof. On the other hand, as mentioned below, also
waxes can be used as surface treatment agent, which are not
chemically bound, but particularly serve to improve dispersion and
especially reduce the viscosity of high viscosity surface treatment
polymers.
[0022] In contrast to this, surface treatment polymers are used to
separate the single particles in the compacted material, and are
not chemically bound to the surface of the primary powder
particles.
[0023] According to the present invention, the surface treatment
polymers preferably have a viscosity at 170.degree. C. of above 500
mPas, whereas the viscosity at 170.degree. C. of the surface
treatment agents preferably is below 500 mPas.
[0024] The process according to the present invention furthermore
allows for the use of extremely low concentrations of surface
treatment products, i.e. surface treatment polymer and surface
treatment agent, such as concentrations ranging from 2% to 10% by
weight based on the weight of the obtained compacted material,
reducing the negative effects on the thermoplastic base polymer and
increasing the compatibility thereof.
[0025] It may furthermore be advantageous that before step e), i.e.
before the mixed material obtained from step d) is transferred to a
cooling unit, it is transferred to a second mixing unit.
[0026] In this second mixing unit optionally further at least one
molten surface treatment polymer is added to and mixed with the
mixed material of step d).
[0027] A further embodiment of the process according to the
invention is that the temperature of the primary powder material is
between 20.degree. C. and 300.degree. C., preferably between
60.degree. C. and 250.degree. C.
[0028] In this respect, the temperature of the optional surface
treatment agent which may be added, is between 20.degree. C. and
300.degree. C., preferably 60.degree. C.-250.degree. C., and more
preferably between 60.degree. C. and 120.degree. C.
[0029] However, the maximum temperature has to be below the
decomposition temperature of any one of the ingredients.
[0030] The primary powder according to the invention may be any
powder as derived from processes such as chemical reactions,
grinding or milling, with or without primary surface treatments,
e.g. with fatty acids such as stearic acid, palmitic acid, etc.
[0031] It may be of natural origin or synthetic.
[0032] In a preferred embodiment of the process according to the
invention the primary powder material is an inorganic powder.
[0033] Then, the inorganic powder may be selected from the group
comprising natural ground calcium carbonate (GCC); precipitated
calcium carbonate (PCC); calcium carbonate-containing minerals such
as dolomite, mixed carbonate based fillers such as calcium
associated with magnesium containing mineral, such as talc, or with
clay; mica; and mixtures of same, such as talc-calcium carbonate or
calcium carbonate-kaolin mixtures, or mixtures of natural ground
calcium carbonate with aluminium hydroxide, mica or with synthetic
or natural fibres, or co-structures of minerals such as
talc-calcium carbonate or talc-titanium dioxide co-structures.
[0034] Preferably the inorganic powder is natural ground calcium
carbonate (GCC), or precipitated calcium carbonate (PCC), or a
mixture of GCC and PCC, or a mixture of GCC and PCC and clay, or a
mixture of GCC and PCC and talc, or talc, or mica.
[0035] In a preferred embodiment, the inorganic powder is selected
from GCC, which preferably is selected from the group comprising
marble, chalk, calcite and limestone; PCC, which is preferably
selected from the group comprising aragonitic PCC, vateritic PCC,
calcitic PCC, rhombohedral PCC, scalenohedral PCC; and mixtures
thereof.
[0036] In another embodiment, the primary powder material is an
organic powder.
[0037] Then, the organic powder is preferably selected from the
group comprising wood flour and modified starch.
[0038] The molten surface treatment polymer should advantageously
have a viscosity such as between 500 and 400 000 mPas, more
preferably between 1000 mPas and 100000 mPas, at 170.degree. C. It
is preferably selected from the group comprising ethylene
copolymers, e.g. ethylene-1-octene copolymers, metallocene based
polypropylenes, polypropylene homopolymer, preferably amorphous
polypropylene homopolymers.
[0039] The optional surface treatment agent advantageously is
selected from the group comprising stearic acid, zinc oxide,
synthetic paraffin wax, polyethylene metallocene wax and
polypropylene wax.
[0040] It has to be noted that conventional functional components
like impact modifiers, stabilizers, etc. may be included during the
mixing process, or to the finished surface treated compacted
material, as well in the final product, i.e. the compounded
thermoplastic resin
[0041] An advantage of the process according to the present
invention lies in the fact that it is a low cost manufacturing
process resulting in lower cost end-product.
[0042] This, inter alia, is due to the fact that the
surface-treated compacted material is processable on a conventional
single-screw plastics conversion equipment without the need to
compound this surface treated material.
[0043] Thus, within the different variants and embodiments of the
method according to the invention, the cylindrical treatment
chamber preferably contains one single-screw high speed mixer, in a
horizontal or vertical position.
[0044] Especially useful in the present invention are conventional
commercially available cylindrical treatment chambers containing a
single-screw high speed mixer, having e.g. the following
parameters:
[0045] length 350 mm, diameter 90mm, at 1000-4000 rpm; length 1200
mm, diameter 230 mm, at 400-3000 rpm; length 150 mm, diameter 150
mm, at 600-1300 rpm.
[0046] Preferably the ratio length:diameter is from 1:1 to 6:1,
more preferably from 2:1 to 5:1, especially 3:1 to 4:1.
[0047] Thus, conventional compounding processes such as those using
twin-screws or Farrel continuous mixers, co-kneaders, Banbury
batch-mixers, or other equivalent equipments can be eliminated.
[0048] A second aspect of the present invention relates to the
surface-treated compacted material obtained by the process
according to the present invention.
[0049] The surface-treated compacted material according to the
invention is preferably characterised in that it is completely
re-dispersible in a thermoplastic polymer matrix without any
compounding step. By completely re-dispersible it is understood
that dispersions, which are visually tested on pressed film under a
binocular magnifier with magnification of 50 of each of the
dispersions made, show no black spots corresponding to the matrix
polymers nor white spots corresponding to the primary powders.
[0050] Such surface-treated compacted materials advantageously are
non-dusting. Such non dusting compacted material, preferably has a
screen residue of more than 80 wt-%, preferably more than 90 wt-%
on a 45 .mu.m screen according to ISO 3310 standard measured by
sieve analysis using a Retsch AS 200 sieve tower
[0051] In the surface treated compacted material, the content of
primary powder material advantageously is from 50 to 99 wt-%,
preferably from 60 to 98 wt-%, more preferably from 75 to 95 wt-%,
most preferably from 80 to 90 wt-%, e.g. 85 wt-%.
[0052] For example, if the primary powder is GCC, it may be present
in the surface treated compacted material in an amount of from 75
to 98 wt-%, preferably of from 86 to 92 wt-%. If the primary powder
is talc, it is especially preferred if it is present in the surface
treated compacted material in an amount of from 75 to 90 wt-%, more
preferably of from 76 to 87 wt-%.
[0053] The content of surface treatment polymer in the compacted
material typically is from 1 to 50 wt-%, preferably from 2 to 40
wt-%, more preferably from 5 to 25 wt-%, especially, from 8 to 14
wt-%, e.g. from 10 to 13 wt-%.
[0054] If surface treatment agent is used in the compacted material
according to the present invention, its content is generally
dependent on the specific surface area of the primary powder.
Advantageously, is present in an amount of from 0.01 to 10 wt-%,
preferably from 0.1 to 7 wt-%, more preferably from 0.5 to 5 wt-%,
e.g. from 1 to 3 wt-%. For example, if the primary powder is GCC,
the surface treatment agent typically is present in an amount of
0.01 wt-% to 10 wt-%, preferably 0.1 wt-% to 3 wt-% based on the
total weight of the compacted material.
[0055] A typical example of a compacted material according to the
invention comprises 90 wt-% primary powder, 9.5 wt-% surface
treatment polymer and 0.5 wt-% surface treatment agent.
[0056] The third object of the present invention concerns the use
of the obtained compacted materials as additives in thermoplastic
polymers.
[0057] Accordingly, the invention allows the uniform dispersion of
the compacted materials into thermoplastic polymers at any
concentration of the compacted material ranging from 0.1 to 80
wt-%, preferably from 1 to 50 wt-%, and more preferably from 5 to
30 wt-%, without the need of preparing intermediate masterbatches
also named concentrates and/or compounds for the formation of the
polymeric end-products.
[0058] A further aspect of the invention is the use of the
surface-treated compacted material according to the invention as an
additive in thermoplastic polymers, as well as a process of
manufacturing thermoplastic polymers by direct addition of the
surface-treated compacted materials into the final thermoplastic
polymers.
[0059] The surface-treated compacted materials according to the
present invention can be used in the manufacture or processing of
any conventional thermoplastic polymers, especially in
polyolefinic, polystyrenic, polyvinylic, or polyacrylic polymers
and/or copolymers. For example, the surface-treated compacted
materials according to the present invention may be used in
polymers such as low density polyethylene (LDPE), linear low
density polyethylene (LLDPE), high density polyethylene HDPE,
polypropylene (PP) such as polypropylene homopolymers, random
polypropylene, heterophasic polypropylene or block copolymers
including polypropylene units, polystyrene (PS), high impact
polystyrene (HI-PS), and polyacrylate.
[0060] In this respect, the surface-treated compacted material can
serve as an additive in the manufacture of blown films, sheets,
pipe profiles, and in such processes like extrusion of pipes,
profiles, cables fibres or the like, compression moulding,
injection moulding, thermoforming, blow moulding, rotational
moulding, etc.
[0061] Finally, a further aspect of the invention are thermoplastic
polymers comprising the compacted materials according to the
invention.
[0062] The scope and interest of the invention will be better
perceived thanks to the following examples which are intended to
illustrate certain embodiments of the invention and are
non-limitative.
DESCRIPTION OF THE FIGURES
[0063] FIG. 1 is a microscopic picture of the initial powder of
Example 1
[0064] FIG. 2 is a microscopic picture of the compacted material of
Example 1.
EXAMPLES
Example 1
[0065] This example relates to the preparation of a surface-treated
non-dusting compacted material according to the present
invention.
[0066] A horizontal "Ring-Layer-Mixer/Pelletizer", namely "Amixon
RMG 30" with process length of 1200 mm, and diameter of 230 mm,
equipped with 3 feeding ports in sequence, and 1 out-let port, was
used. The cylinder is fitted with a heating/cooling double wall.
Surface treatment and compacting is obtained by a rotating,
cylindrical, pin-fitted screw.
[0067] Component A (Primary Powder Material):
[0068] Natural calcium carbonate (GCC)) with a mean particle size
of 2.7 .mu.m, treated with 0.5 wt-% stearic acid, is preheated to
110.degree. C., and fed gravimetrically into the first feed port at
the rate of 22.6 kg/hr.
[0069] Component B: (Surface Treatment Polymer)
[0070] Component B is injected in liquid state at a temperature of
230.degree. C. through feeding port 2 at the required rate (kg/hr.)
related to component A to be surface treated, in this example at
2.4 kg/hr.
[0071] Component B consists of a blend of: [0072] 80 wt-%
ethylene-1-octene-copolymer (e.g. Affinity GA 1900/Dow), Density
(ASTM D792) 0.87 g/cm.sup.3 [0073] 20 wt-% metallocene based
polypropylene wax (e.g. Licocene PP-1302/Clariant), Density
(23.degree. C.; ISO 1183)) 0.87 g/cm.sup.3.
[0074] Mixing
[0075] Surface treatment and compacting is carried out in the
"Ring-Layer-Mixer/Pelletizer" at 180.degree. C. and a screw speed
of 800 rpm.
[0076] The surface treated product leaves the Mixer/Pelletizer
through the outlet port, is transferred by gravity into a second
Ring-Layer-Mixer/Pelletizer for compacting and cooling, operated at
a temperature of 140.degree. C. and a screw speed of 400 rpm. In
this example, both units are of identical size and dimensions. The
resulting surface treated and compacted material leaves the unit
through the outlet port, and is free of dust and free flowing.
[0077] Application:
[0078] The surface treated/compacted material has a concentration
of 90.5 wt-% of calcium carbonate (GCC). The quality of the surface
treatment is evaluated by the degree of re-dispersion when
extruding a blend of compacted material and virgin polymer.
[0079] Precisely, in this example, for the blown film production, a
LLDPE (Dowlex NG 5056G/Dow) was used, adding 17 wt-% of the
compacted material and 83 wt-% weight of said LLDPE.
[0080] The equipment used therefor was a conventional Dr. Collin
single screw extruder, Type E-25P, equipped with blown film die of
60 mm diameter and 1.2 mm thickness. Temperature profile for the
extruder was at 220.degree. C., screw speed at 70 rpm.
[0081] Both products, LLDPE resin and the compacted material were
fed by gravimetric dosing. The resulting film had a thickness of 40
.mu.m.
[0082] For comparison, a standard type, LLDPE-based calcium
carbonate master batch, containing 70 wt-% of calcium carbonate
(Omyalene 2011A/Omya), is processed under identical conditions and
the same final concentration of calcium carbonate in the film.
[0083] The resulting films for both products, the compacted
material and Omyalene 2011A are visually controlled under a
binocular magnifier with magnification of 50 and found free of any
undispersed agglomerates. For further evaluation, both blown film
samples containing 17 wt-% of the compacted material, and 22 wt-%
of master batch (Omyalene 2011A), respectively, were tested for
Dart-drop test (ASTM D 1709) and Elemendorf-tear resistance test
(ISO 6383-2).
[0084] The film made with the compacted material had a dart drop of
620 g and a tear resistance of 710 cN and 810 cN in machine and
cross direction.
[0085] The film containing masterbatch had a dart drop value of 630
g and a tear resistance of 670 cN and 880 cN in machine and cross
direction.
[0086] These results confirm the complete and uniform dispersion of
the calcium carbonate (GCC) of the compacted material when
processed on a standard single screw extruder.
[0087] Free flow properties of the compacted material are evaluated
by DIN-53492 standard.
[0088] Results are: [0089] untreated natural calcium carbonate
powder: 10 mm opening: no flow [0090] compacted material as per
example 1: 10 mm opening: 7 sec/150 g
[0091] Particle Size
[0092] Evaluation according to ISO 3310.
TABLE-US-00001 Result: 92 wt-% <500 microns 56 wt-% <250
microns 35 wt-% <160 microns 4 wt-% <45 microns
[0093] These results confirm that the compacted material of example
1 is free of dust and free flowing.
[0094] The effect of the process is also clearly shown looking at
FIG. 1, being a microscopic picture of the initial powder and FIG.
2 being a microscopic picture of the compacted material of example
1.
Example 2
[0095] For surface treatment and cooling, the same equipment and
processing parameters were used as in example 1.
[0096] Component A (Primary Powder Material):
[0097] Natural talc powder with a mean particle size of 10 .mu.m
(Finntalc M30SL/Mondo Minerals) is gravimetrically fed into feed
port 1 at a rate of 20 kg/hr.
[0098] Component B (Surface Treatment Polymer):
[0099] Component B is injected in liquid state at a temperature of
230.degree. C. into feed port 2 at a rate of 5 kg/hr.
[0100] Component B consists of a blend of: [0101] 90 wt-%
metallocene based PP (e.g. Metocene HM 1425/Lyondel-Basell). [0102]
10 wt-% Zn-stearate (e.g. Zincum 5/Baerlocher).
[0103] The resulting, surface treated and compacted material
contains 80 wt-% of talc, is free of dust and free flowing.
[0104] Application:
[0105] The degree of dispersability is evaluated by extruding a
blend of 20 wt-% of the compacted material and 80 wt-% of virgin
polymer. The extrusion is carried out on a conventional Dr. Collin
single screw extruder type E25P, fitted with a flat die (2.times.20
mm opening) at a temperature profile of 190.degree. C. and a screw
speed of 80 rpm. The resulting stripe is then pressed on a hot
press to a sheet of 0.2 mm thickness.
[0106] For this example, a polypropylene homopolymer type
TM-6100K/Montell and a HDPE type Hostalene GC-7200/Clariant were
used as the virgin polymers.
[0107] By visual examination of the pressed sheets under a
binocular magnifier with magnification of 50, no agglomerates or
undispersed particles could be detected, and the dispersion is
judged as excellent in both polymers.
[0108] Free flow properties of the compacted materials are
evaluated by DIN-53492 standard.
[0109] Results are: [0110] untreated natural talc powder: 10 mm
opening: no flow [0111] compacted material as per example 2: 10 mm
opening: 18 sec/150g
Example 3
[0112] For the powder treatment a high speed batch mixer from
MTI-Mischtechnik Industrieanlagen GmbH Type LM 1.5/2.5/5 with a
2.51 vessel and with a three part standard mixing tool was used.
The mixer was heated to 175.degree. C. 364 g of a calcium carbonate
like in example 1 were filled in the vessel. The vessel was closed
and the mixer was run for 2 minutes at 700 rpm. Then the mixer was
opened and 32 g of polypropylene homopolymer with a solid density
of 0.86 g/ml and a melting point (DSC) of 152.degree. C. plus 4g
zinc oxide type Barlocher Zincum 5 were added to the preheated
powder. The mixer was closed again and run for 12 minutes at 700
rpm.
[0113] To test the dispersion of the obtained treated powder a Dr.
Collin lab extruder FT-E20T-IS with a standard screw and with a
standard tape die was used. All heating zones were heated to
175.degree. C. and the extruder was run at 100 rpm. 80 wt-% HDPE
Type LyondellBasell Hostalen GC 7260 and 20 wt-% of the obtained
powder were continuously fed in the extruder by a gravimetric
dosage system. 10 g of extruded tape were then compression moulded
between two chromed steel plates at 190.degree. C. The obtained
film was optically inspected under a binocular magnifier with
magnification of 50 and showed no visible agglomerates.
Example 4
[0114] The compacted material of example 1, containing 90.5 wt-% of
natural calcium carbonate and 9.5 wt-% of surface treatment polymer
was evaluated for sheet extrusion applications in polystyrene.
[0115] General purpose polystyrene from BASF type 158K (GPPS) and
high impact polystyrene from BASF type 486M (HIPS) were used. 56
wt-% of each polystyrene were added to 44 wt-% of said compacted
material.
[0116] Both components were continuously gravimetrically dosed to
the feed hopper of the processing extruder. In the case of GPPS the
total feed rate was 15.6 kg/h and in the case of HIPS it was 14.7
kg/h. A conventional Collin single screw extruder type E25P with a
Collin flat film extrusion die and a Collin polishing stack were
used to produce a 250 mm wide and 1 mm thick sheet. The temperature
profile of the extruder was 180.degree. C., 195.degree. C.,
230.degree. C., 230.degree. C. and 230.degree. C. The extrusion die
was kept at 230.degree. C. and the calendaring rolls at 100.degree.
C. The die gap was 1.2 mm and the nip width of the calendaring
rolls was 1.0 mm. The line sped was set to 0.8 m/min. The screw was
underfed at a speed of 160 rpm. With this set up sheets without
visible agglomerates under a binocular magnifier with magnification
of 50 could be produced.
[0117] 10 g of each extruded sheet were then compression moulded
between two chromed steel plates at 190.degree. C. The obtained
film was optically inspected under a binocular magnifier with
magnification of 50 and showed no visible agglomerates.
* * * * *