U.S. patent application number 12/470501 was filed with the patent office on 2009-09-10 for novel rheology regulators such as ground natural calcium carbonates optionally treated with a fatty acid or salt and their use.
This patent application is currently assigned to OMYA DEVELOPMENT AG. Invention is credited to Pierre Blanchard, Detlef Gysau, Henny Loman, Marion Loman-Oonk, Patrick Trouve.
Application Number | 20090227721 12/470501 |
Document ID | / |
Family ID | 9531409 |
Filed Date | 2009-09-10 |
United States Patent
Application |
20090227721 |
Kind Code |
A1 |
Blanchard; Pierre ; et
al. |
September 10, 2009 |
NOVEL RHEOLOGY REGULATORS SUCH AS GROUND NATURAL CALCIUM CARBONATES
OPTIONALLY TREATED WITH A FATTY ACID OR SALT AND THEIR USE
Abstract
The invention relates to the selection of a natural calcium
carbonate crushed to a high degree of fineness, possibly treated
with one or more fatty acids or one or more of their salts or
mixtures thereof, and its use as a rheology regulator for polymeric
compositions. The specific surface area is 14 to 30 m.sup.2/g
measured according to the BET method to ISO 4652, and the oil
absorption is greater than 16 measured according to ISO 787-V
(Rub-out method). The conditions of mixing of the constituents and
manufacture are improved, as well as the properties of the final
product.
Inventors: |
Blanchard; Pierre;
(Reyrieux, FR) ; Gysau; Detlef; (Zofingen, CH)
; Trouve; Patrick; (Clamart, FR) ; Loman;
Henny; (Safenwil, CH) ; Loman-Oonk; Marion;
(Almelo, NL) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
OMYA DEVELOPMENT AG
Oftringen
CH
|
Family ID: |
9531409 |
Appl. No.: |
12/470501 |
Filed: |
May 22, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11733408 |
Apr 10, 2007 |
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12470501 |
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10781686 |
Feb 20, 2004 |
7300974 |
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11733408 |
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09806473 |
Jul 3, 2002 |
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PCT/IB99/01625 |
Oct 1, 1999 |
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10781686 |
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Current U.S.
Class: |
524/425 |
Current CPC
Class: |
C09K 3/10 20130101; C01P
2006/12 20130101; C08K 3/26 20130101; C08K 2003/265 20130101; C01F
11/18 20130101; C09K 2200/0239 20130101; C09D 5/34 20130101; C01P
2006/19 20130101 |
Class at
Publication: |
524/425 |
International
Class: |
C08K 3/26 20060101
C08K003/26 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 7, 1998 |
FR |
98/12714 |
Claims
1. A method of regulating the viscosity as a function of speed of
flow during the application of a plastisol to a substrate,
comprising adding natural calcium carbonate, crushed to a high
degree of fineness, with a specific surface area of around 14 to 30
m.sup.2/g measured according to the BET method to ISO 4652, to a
plastisol, and adjusting the amount of added natural calcium
carbonate in order to achieve a desired relationship between speed
of flow and viscosity of the plastisol.
2. The method of claim 1, wherein the calcium carbonate has a
specific surface area of around 16 to 24 m.sup.2/g.
3. The method of claim 1, wherein the calcium carbonate has a
specific surface area of around 20 m.sup.2/g.
4. The method of claim 1, wherein the natural calcium carbonate has
a specific surface area of at least 14.4 m.sup.2/g.
5. The method of claim 1, wherein the natural calcium carbonate has
a specific surface area of at least 16 m.sup.2/g.
6. The method of claim 1, wherein the natural calcium carbonate has
a specific surface area of at least 16.5 m.sup.2/g.
7. The method of claim 1, wherein the natural calcium carbonate has
a specific surface area of no higher than 22 m.sup.2/g.
8. The method of claim 1, wherein the natural calcium carbonate has
a specific surface area of no higher than 28 m.sup.2/g.
9. The method of claim 1, wherein the natural calcium carbonate is
treated with at least one fatty acid containing 10 to 24 carbon
atoms or a salt thereof selected from the group consisting of
calcium salt, magnesium salt, zinc salt, and mixtures thereof.
10. The method of claim 1, wherein the natural calcium carbonate is
treated with stearic acid or a calcium salt thereof in a proportion
of around 0.01% to 5% by weight.
11. The method of claim 1, wherein the natural calcium carbonate is
treated with stearic acid or a calcium salt thereof in a proportion
of around 1% to 4% by weight.
12. The method of claim 1, wherein the natural calcium carbonate
has an oil absorption which is greater than 16 g/100 g measured
according to ISO 787-V (Rub-out method).
13. The method of claim 1, wherein the plastisol is PVC-based.
14. A method of regulating the rheology during the application of a
plastisol to a substrate, comprising adding natural calcium
carbonate, crushed to a high degree of fineness, with a specific
surface area of around 14 to 19.5 m.sup.2/g measured according to
the BET method to ISO 4652, to a plastisol, in an amount to
regulate the rheology of the plastisol.
15. The method of claim 14, wherein the natural calcium carbonate
has a specific surface area no higher than 16.5 m.sup.2/g.
16. The method of claim 14, wherein the natural calcium carbonate
has an oil absorption which is greater than 16 g/100 g measured
according to ISO 787-V (Rub-out method).
17. The method of claim 14, wherein the plastisol is PVC-based.
Description
[0001] This is a divisional application of U.S. application Ser.
No. 11/733,408, filed Apr. 10, 2007, which is a continuation
application of U.S. application Ser. No. 10/781,686, filed Feb. 20,
2004, which is a continuation of U.S. application Ser. No.
09/806,473, filed Jul. 3, 2002, which is a 371 of PCT/IB99/01625,
filed Oct. 1, 1999.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to the technical sector of
sealants, coatings, adhesives, plastisols or rubbers.
[0004] 2. Description of the Related Art
[0005] There are known, in this field, polymeric compositions, with
or without fillers, for example polyurethanes with a silane
termination which are used as sealants or adhesives setting in
moist conditions.
[0006] In the presence of moisture, terminal silane groups undergo,
in a known manner, a hydrolysis and condensation reaction. A stable
siloxane lattice (Si--O--Si) then foams.
[0007] Such products have many applications in various industrial
fields such as the transport and building industries.
[0008] More and more sophisticated formulations have therefore been
sought, notably of the "single-component" type, capable of being
applied to various substrates posing problems which are more and
more difficult to resolve.
[0009] The composition of this type of formulation comprises one or
more fillers, which can be one or more calcium carbonates normally
referred to as "fine".
[0010] It has been discovered according to the invention that,
surprisingly, the selection of a natural calcium carbonate ground
to a high degree of fineness, which will be described below, or
this calcium carbonate treated also as described below, makes it
possible to achieve an unequalled set of satisfactory properties
for the final product. These include notably good adaptability to
adhesion on many types of substrate, such as certain difficult
plastics, including without a prior primer coating called "primer",
a reduction in the quantity of polymer required (and therefore a
reduction in the cost of materials), or an appreciable reduction in
the mixing time (which may reach a factor of 1/2 for each step,
which has an obvious great economic advantage).
[0011] It is even more surprising to find that this remarkable
improvement in a set of properties of the final product does not
take place, as an expert would logically predict, to the detriment
of the final mechanical properties, or properties such as
resistance to chemical agents or UV radiation or similar properties
conventionally required of such agents.
[0012] Formulations of the plastisol type based on polyvinyl
chloride (PVC) are also known.
[0013] It should be stated here that a plastisol designates a
suspension of one or more PVC resins in a liquid plasticiser and
additives such as mineral fillers, stabilisers, mineral and/or
organic pigments, expansion agents, adhesion promoters, fluidifiers
and others.
[0014] After thermal gelling, the plastisol takes the appearance of
a more or less flexible compact mass.
[0015] One of the mineral fillers normally used consists of a
synthetic calcium carbonate obtained chemically (precipitated
calcium carbonate: PCC) such as for example the product Winnofil
SPT Premium.TM. from Zeneca.
[0016] According to the invention, it is proposed to use, as a
rheology regulating mineral material, a natural calcium carbonate
crushed to a high degree of fineness whether or not with a
dispersing agent present. This natural calcium carbonate is chosen
from amongst chalk, calcite or marble, alone or in a mixture, or
from amongst these same calcium carbonates treated by means of at
least one fatty acid or its salt or a mixture thereof and
preferentially using stearic acid or its salt, such as notably
calcium, magnesium or zinc stearate and highly preferably using
stearic acid or its calcium salt, the whole as described in more
detail below.
[0017] The rheology regulator product according to the invention is
characterised in that it is a case of a natural calcium carbonate,
with a specific surface area of around 14 to 30 m.sup.2/g,
preferably 16 to 24 m.sup.2/g and highly preferentially around 20
m.sup.2/g, measured according to the BET method to ISO 4652.
[0018] This carbonate is possibly treated with at least one fatty
acid or its salt or a mixture thereof, an acid which is an acid
containing 10 to 24 atoms of carbon, and more particularly stearic
acid or its salt, such as notably calcium, magnesium or zinc
stearate and highly preferentially by means of stearic acid or its
calcium salt, preferably at the rate of 0.01% to 5% by weight and
more preferentially 1% to 4% by weight.
[0019] It should be noted here that stearic acid means stearic
acids of industrial quality composed mainly of 50% to 70%
octadecanoic acid and 30% to 50% hexadecanoic acid.
[0020] An original advantage of the product according to the
invention is that this product is a calcium carbonate which fulfils
a rheology regulating function. This function is normally devolved
to the polymers and additives contained in the polymeric
formulation, such as for example viscosity depressors, and the
Applicant was surprised to see it fulfilled by a product of the
type consisting of a material with a natural mineral filler with a
high degree of fineness.
[0021] The product selected according to the invention consists of
a natural calcium carbonate crushed very finely with a dispersant
present or not and possibly treated by means of at least one fatty
acid or its salt or a mixture thereof.
[0022] Another of its characteristics lies in its oil absorption,
which is greater than 16, measured according to ISO 787-V (Rub-out
method).
[0023] A calcium carbonate with a specific surface area of 19 to 26
m.sup.2/g was described in the patent EP 0 795 588. It is known
according to this document as a pigment giving brightness and
opacity in the papermaking field. This field of application is
totally different. In addition, such a function is completely
different from that of a rheology regulating action, and nothing
would suggest either the function brought to light by the
invention, nor the fact that this novel application could lead to a
surprising set of properties having a great economic advantage.
[0024] The invention also relates to the use, as a rheology
regulator for the preparation of sealants or coatings, adhesives,
plastisols or rubbers, of these natural calcium carbonates crushed
to a very high degree of fineness, possibly treated by means of at
least one fatty acid or its salt, notably of calcium, magnesium or
zinc or a mixture thereof. This acid, which is an acid containing
10 to 24 atoms of carbon, is more particularly stearic acid or its
salt, such as notably calcium, magnesium or zinc stearate and
highly preferentially stearic acid or its calcium salt. The
processing takes place preferably at the rate of 0.01% to 5% by
weight and more preferentially 1% to 4% by weight of at least one
fatty acid or its salt or a mixture thereof.
[0025] The invention also relates to the use of dispersions or
suspensions, in an organic medium, of these calcium carbonates,
treated or non-treated, as a rheology regulator for the preparation
of sealants or coatings, adhesives, plastisols or rubbers.
[0026] The invention also relates to polymeric compositions of
plastisols, sealant or coating, elastomer or rubber containing, as
a rheology regulator, the said natural calcium, carbonates crushed
to a high degree of fineness, possibly treated by means of at least
one fatty acid or its salt or a mixture thereof.
[0027] Other characteristics and advantages of the invention will
be understood more clearly from a reading of the following
description and examples. These examples should not be taken to
represent any limitative aspect of the invention.
[0028] In the examples, the products have the following
characteristics:
[0029] Product A:
[0030] A filler of the prior art, consisting of a natural calcium
carbonate of the chalk type, crushed and dried, not treated, with a
mean grain diameter of 0.67 micrometres measured by means of the
Sedigraph 5100 from Micromeritics, with a specific surface area of
11 m.sup.2/g measured according to the BET method to ISO 4652.
[0031] Product B:
[0032] A rheology regulator according to the invention, consisting
of a natural calcium carbonate of the chalk type, crushed and
dried, not treated, with a mean grain diameter of 0.60 micrometres
measured by means of the Sedigraph 5100 from Micromeritics, with a
specific surface area of 19.5 m.sup.2/g measured according to the
BET method to ISO 4652 and with an oil absorption of 18.75 measured
according to ISO 787-V (Rub-out method).
[0033] Product C:
[0034] A rheology regulator according to the invention, consisting
of a natural calcium carbonate of the Urgonian calcite type,
crushed by the wet method and dried, not treated, with a mean grain
diameter of 0.44 micrometres measured by means of the Sedigraph
5100 from Micromeritics, with a specific surface area of 16.5
m.sup.2/g measured according to the BET method to ISO 4652 and with
an oil absorption of 20 measured according to ISO 787-V (Rub-out
method).
[0035] Product D:
[0036] A rheology regulator according to the invention, consisting
of a natural calcium carbonate of the chalk type, crushed by the
wet method and dried, treated by the use of 3% by weight stearic
acid, with a mean grain diameter of 0.59 micrometres measured by
means of the Sedigraph 5100 from Micromeritics, with a specific
surface area, after treatment, of 16 m.sup.2/g measured according
to the BET method to ISO 4652 and with an oil absorption, after
treatment, of 16.3 measured according to ISO 787-V (Rub-out
method).
[0037] Product E:
[0038] A rheology regulator according to the invention, consisting
of a natural calcium carbonate of the Urgonian calcite type,
crushed by the wet method and dried, not treated, with a mean grain
diameter of 0.58 micrometres measured by means of the Sedigraph
5100 from Micromeritics, with a specific surface area of 14.4
m.sup.2/g measured according to the BET method to ISO 4652 and with
an oil absorption of 17.9 measured according to ISO 787-V (Rub-out
method).
[0039] Product F:
[0040] A rheology regulator according to the invention, consisting
of a natural calcium carbonate of the chalk type, crushed by the
wet method and dried, treated by the use of 1% by weight stearic
acid, with a resulting granulometry of 96%<1 micrometre and
39%<0.2 micrometres measured by means of the Sedigraph 5100 from
Micromeritics, with a specific surface area, after treatment, of 28
m.sup.2/g measured according to the BET method to ISO 4652 and with
an oil absorption, after treatment, of 19.5 measured according to
ISO 787-V (Rub-out method).
[0041] Product G:
[0042] A rheology regulator according to the invention, consisting
of a natural calcium carbonate of the chalk type, crushed by the
wet method and dried, not treated, with a specific surface area of
22 m.sup.2/g measured according to the BET method to ISO 4652 and
an oil absorption of 19.4 measured according to ISO 787-V (Rub-out
method).
[0043] Product H:
[0044] A filler of the prior art consisting of a precipitated
calcium carbonate sold by Zeneca under the name Winnofil
SPT.TM..
[0045] Product I:
[0046] A filler of the prior art, consisting of natural calcium
carbonate of the chalk type, crushed by the wet method and dried,
treated by means of 1% stearic acid, with a mean diameter of 1.4
micrometres measured by means of the Sedigraph 5100 from
Micromeritics and with a specific surface area of 6 m.sup.2/g
measured according to the BET method to ISO 4652.
[0047] Product J:
[0048] A filler of the prior art, consisting of a natural calcium
carbonate of the chalk type, crushed by the wet method and dried,
treated by the use of 1% by weight stearic acid, with a mean
diameter of 1 micrometre measured by means of the Sedigrapb 5100
from Micromeritics and a specific surface area of 10 m.sup.2/g
measured according to the BET method to ISO 4652.
[0049] Product K:
[0050] A filler of the prior art consisting of a treated
precipitated calcium carbonate sold by Solvay under the name Socal
U1S2.
EXAMPLE 1
[0051] This example relates to the use of calcium carbonate as a
rheology regulator for the preparation of plastisols.
[0052] In these tests, tests were carried out on the replacement of
the synthetic calcium carbonate obtained by precipitation, of the
prior art, or precipitated calcium carbonate (PCC), by the specific
natural calcium carbonate according to the invention.
[0053] In a formulation of the plastisol type based on PVC
(polyvinyl chloride) containing no calcium carbonate, it was sought
to compare the effect of the replacement of 50% to 100% of the
mineral filler normally used, namely a precipitated calcium
carbonate, by a natural calcium carbonate crushed to a high degree
of fineness according to the invention.
[0054] To do this, with 75 g of plastisol without filler, the
calcium carbonate to be tested was mixed in a 7 cm diameter
receptacle and the mixture was homogenised with a spatula. Then the
mixture was put in dispersion for two minutes using a "Pendraulik"
.TM. LD50 laboratory mixing appliance, the diameter of the
dispersing disc being 5 cm, the speed of rotation of the disc being
2700 rev/min (manual setting at position 3).
[0055] The dispersing being terminated, the viscosity was measured
by means of "Rheomat 120" M equipment, a measuring appliance
according to DIN 125, at 20.degree. C.
[0056] Test No. 1:
[0057] This test illustrates the prior art and uses 20 g of a
precipitated calcium carbonate sold by Zeneca under the name
Winnofil SPT.TM. (product H) and 5 g of natural calcium carbonate
sold under the name Juraperle.TM. BS by Juraweiss.
[0058] Test No. 2:
[0059] This test illustrates the prior art and uses 13 g of a
precipitated calcium carbonate sold by Zeneca under the name
Winnofil SPT.TM. (product H) and 12 g of product A according to the
prior art.
[0060] Test No. 3:
[0061] This test illustrates the invention and uses 25 g of product
B according to the invention.
[0062] Test No. 4:
[0063] This test illustrates the prior art and uses 20 g of a
precipitated calcium carbonate sold by Zeneca under the name
Winnofil SPT.TM. (product H).
[0064] Test No. 5:
[0065] This test illustrates the invention and uses 10 g of a
precipitated calcium carbonate sold by Zeneca under the name
Winnofil SPT.TM. (product H) and 15 g of product D according to the
invention.
[0066] Test No. 6:
[0067] This test illustrates the invention and uses 10 g of a
precipitated calcium carbonate sold by Zeneca under the name
Winnofil SPT.TM. (product H) and 15 g of product C according to the
invention.
[0068] Test No. 7:
[0069] This test illustrates the invention and uses 13 g of a
precipitated calcium carbonate sold by Zeneca under the name
Winnofil SPT.TM. (product H) and 12 g of product E according to the
invention.
[0070] Test No. 8:
[0071] This test illustrates the invention and uses 10 g of a
precipitated calcium carbonate sold by Zeneca under the name
Winnofil SPT.TM. (product H), 5 g of natural calcium carbonate sold
under the name Juraperle.TM. BS by Juraweiss and 10 g of product D
according to the invention.
[0072] Test No. 9:
[0073] This test illustrates the invention and uses 10 g of a
precipitated calcium carbonate sold by Zeneca under the name
Winnofil SPT.TM. (product H), 5 g of natural calcium carbonate sold
under the name Juraperle.TM. BS by Juraweiss and 10 g of product E
according to the invention.
[0074] Test No. 10:
[0075] This test illustrates the invention and uses, for a mixture
with 72 g of plastisol, 10 g of a precipitated calcium carbonate
sold by Zeneca under the name Winnofil SPT (product H), 5 g of
natural calcium carbonate sold under the name Juraperle.TM. BS by
Juraweiss and 13 g of product E according to the invention.
[0076] The results of the viscosity measurements as a function of
the speed of flow according to DIN 125 at 20.degree. C. are set out
in Tables Ia and Ib below.
TABLE-US-00001 TABLE Ia Prior Prior Inven- Prior Inven- art art
tion art tion TEST N.degree. 1 2 3 4 5 COMPO- Plastisol 75.00 75.00
75.00 75.00 75.00 SITION without filler (in g) PCC (in g) 20.00
13.00 -- 25.00 10.00 Juraperle .TM. 5.00 -- -- -- -- BS (in g)
Product A -- 12.00 -- -- -- (in g) Product B -- -- 25.00 -- -- (in
g) Product D -- -- -- -- 15.00 (in g) Weight of 100.00 100.00
100.00 100.00 100.00 mixture (in g) Viscosity mPa s Speed of Test
N.degree. Test N.degree. Test N.degree. Test N.degree. Test
N.degree. flow s -1 1 2 3 4 5 RHEOL- 20 18200 17700 15200 17600
17100 OGY 40 10040 9650 8430 9900 9650 60 7260 7100 6280 7200 7100
80 5890 5730 5170 5850 5700 100 5100 4880 4390 5000 4800 120 4490
4380 3980 4450 4350 140 4100 4020 3550 3990 3990 160 3780 3650 3310
3650 3650 180 3460 3400 3110 3400 3380 200 3320 3220 2950 3190 3170
220 3140 3030 2780 3110 3000 240 3000 2870 2620 2890 2820 260 2870
2760 2520 2740 2700 280 2760 2680 2420 2610 2600 300 2660 2570 2350
2490 2490
TABLE-US-00002 TABLE Ib Inven- Inven- Inven- Inven- Inven- tion
tion tion tion tion Test N.degree. 6 7 8 9 10 COMPO- Plastisol
75.00 75.00 75.00 75.00 72.00 SITION without filler (in g) PCC (in
g) 10.00 13.00 10.00 10.00 10.00 Juraperle .TM. -- -- 5.00 5.00
5.00 BS (in g) Product C 15.00 -- -- -- -- (in g) Product D -- --
10.00 -- -- (in g) Product E -- 12.00 -- 10.00 13.00 (in g) Weight
of 100.00 100.00 100.00 100.00 100.00 mixture (in g) Viscosity mPa
s Speed of Test N.degree. Test N.degree. Test N.degree. Test
N.degree. Test N.degree. flow s.sup.-1 6 7 8 9 10 RHEOL- 20 12700
17300 13100 12500 17000 OGY 40 7280 9450 7600 7160 9500 60 5360
6950 5630 5250 7030 80 4430 5600 4850 4330 5580 100 3820 4830 4040
3780 4800 120 3400 4230 3600 3300 4320 140 3110 3950 2290 3000 3790
160 2860 3550 3040 2770 3550 180 2680 3260 2850 2590 3280 200 2520
3110 2680 2480 3080 220 2400 2910 2550 2320 2950 240 2290 2790 2430
2200 2800 260 2190 2670 2340 2130 2710 280 2120 2580 2250 2050 2610
300 2040 2490 2180 1970 2490
[0077] A reading of the table shows that the use of the calcium
carbonate according to the invention makes it possible to regulate
the rheological behaviour of the plastisol composition, even when
100% of the precipitated calcium carbonate has been replaced by the
calcium carbonate according to the invention.
EXAMPLE 2
[0078] This example relates to the study of the conventional
mechanical properties conferred by product F according to the
invention, that is to say a natural chalk crushed so as to obtain a
specific surface area of 28 m.sup.2/g, on mixtures based on
plasticised PVC, in comparison with mixtures filled by means of
natural calcium carbonates well known in the prior art.
[0079] For each of these tests, the following mixture was
produced:
TABLE-US-00003 "SOLVIC 239 D" PVC sold by Solvay 100 Dioctyl
phthalate (Jayflex .TM. DOP from Exxon) 50 Dibasic lead sulphate 1
Tribasic lead sulphate 2 Filler to be tested 80
[0080] Preparation of the Composition:
[0081] The dry mixtures or "dry blends" were prepared in a
"GUEDU".TM. adiabatic mixer at 100.degree. C. for a period of 15
minutes. The mixtures were then gelled on cylinders at 150.degree.
C. in a mixing mill. For all the mixtures, this operation was
performed in 12 minutes.
[0082] Sheets of 90.times.90.times.2 mm were then moulded at
160.degree. C. after preheating of the blank for 3 minutes and
pressurising for 2 minutes before cooling, using a compression
press.
[0083] The test pieces necessary for determining the mechanical
properties were cut from these sheets.
[0084] The different calcium carbonates tested were:
[0085] Test No. 11:
[0086] This test illustrates the prior art and uses a natural
chalk, treated with 1% stearic acid, with a specific surface area
of 6 m.sup.2/g measured according to the BET method to ISO 4652
(product 1).
[0087] Test No 12:
[0088] This test illustrates the prior art and uses a natural
chalk, treated with 1% stearic acid, with a specific surface area
of 10 m.sup.2/g measured according to the BET method to ISO 4652
(product J).
[0089] Test No. 13:
[0090] This test illustrates the invention and uses product F
according to the invention.
[0091] The mechanical properties were assessed by means of
dynamometric tests (tensile strength, breaking elongation, modulus
100%) carried out using the Instron.TM. equipment according to ISO
37, at a temperature 23.degree. C. and with a traction speed of 10
cm/min.
[0092] The ASTM-C tear strength was for its part determined
according to the method of ISO R-34 and Shore C hardness according
to the method of ISO 868.
[0093] The results of these measurements of mechanical properties
are set out in Table II below.
TABLE-US-00004 TABLE II Test No. Prior art Prior art Invention 11
12 13 Tensile strength (daN/cm.sup.2) 128 130 136 Breaking
elongation (%) 300 260 172 Modulus 100% (daN/cm.sup.2) 83 106 127
ASTM-C tear strength (daN/cm) 47 56 58 Shore C hardness at 15 s (in
daN/cm) 60 64 74
[0094] It can be seen that the mechanical properties obtained are
excellent and are superior to those obtained with natural calcium
carbonates which are crushed but which have a specific surface area
outside the scope of the invention.
[0095] The invention therefore makes it possible to optimise the
formulations according to the mechanical property to be
favoured.
EXAMPLE 3
[0096] This example relates to the use of calcium carbonates as a
rheology regulator for the preparation of elastomer based on
natural or synthetic rubber.
[0097] It was sought in this example to assess the effect of the
specific surface area of a crushed natural chalk according to the
invention on the properties of mixtures based on natural and
synthetic rubbers, in comparison with a precipitated calcium
carbonate of the prior art.
[0098] To do this, for each of Tests 14 and 15, the following
mixture was produced;
TABLE-US-00005 Natural rubber (smoked sheet quality RSS 1) 100 SBR
rubber (styrene-butadiene, Cariflex .TM. 1502 from Shell) 40 Zinc
oxide (snow quality) from Vieille Montagne 5 Stearic acid 2 Sulphur
1.5 N-cyclohexyl 2 benzothiazyl sulphenamide (Vulcafor .TM. CBS
from 1 Vulnax) Tetramethylthiuram disulphide (Vulkacit .TM. DTMT
from Bayer) 0.5 Calcium carbonate to be tested 100
[0099] Test No. 14:
[0100] This test illustrates the prior art and uses a precipitated
calcium carbonate sold by Solvay under the name Socal U1S2 (product
K).
[0101] Test No. 15:
[0102] This test illustrates the invention and uses product F
according to the invention.
[0103] These two tests were carried out as follows:
[0104] A pure gum master-batch was prepared, by the successive
incorporation of the various ingredients, except for calcium
carbonate, according to the normal technique of experts, on a
mixing mill regulated for temperature, by mixing for 10 minutes
(friction I/I,4) at 60.degree. C.
[0105] From this master-batch two samples were taken in which the
calcium carbonates to be tested had been incorporated, by mixing at
60.degree. C. for 12 minutes.
[0106] After determination of the vulcanisation optima at
155.degree. C. using a Monsanto flow meter, sheets were moulded and
vulcanised to this optimum in order to effect the measurement of
the mechanical properties according to the same operating method as
in the previous tests.
[0107] The results of the mechanical properties are set out in
Table III below.
TABLE-US-00006 TABLE III Test No. Prior art Invention 14 15
Vulcanisation optimum at 155.degree. C. 5 min. 15 s 5 min. Tensile
strength daN/cm.sup.2 119 109 Modulus 300% daN/cm.sup.2 41 39
Elongation % 500 485 Tear strength ASTM-C daN/cm 23 26 Shore A
hardness (15 s) 61 61
[0108] It can be seen that the product according to the invention
reduces the implementation time (the vulcanisation optimum) as well
as the tear strength properties.
[0109] Likewise Tests 16, 17 and 18 were carried out using the
following formulation:
TABLE-US-00007 SBR rubber (styrene-butadiene, Cariflex .TM. 40 1502
from Shell) Natural rubber (smoked sheet quality RSS 1) 60 Zinc
oxide (snow quality) from Vieille Montagne 5 Stearic acid 2 Sulphur
2 N-cyclohexyl 2 benzothiazyl sulphenamide 0.9 (Vulcafor .TM. CBS
from Vulnax) Diorthotolylguanidine accelerator (Vulkafor .TM. 0.3
DOTG from Vulnax) Calcium carbonate to be tested 100
[0110] Test No. 16:
[0111] This test illustrates the prior art and uses a precipitated
calcium carbonate sold by Solvay under the name Socal U1S2 (product
K).
[0112] Test No. 17:
[0113] This test illustrates the prior art and uses a calcium
carbonate of the chalk type, crushed by the wet method and dried,
treated, with a mean diameter of 1.4 micrometres measured by means
of the Sedigraph 5100 from Micromeritics and with a specific
surface area of 10 m.sup.2/g measured according to the BET method
to ISO 4652 (product J).
[0114] Test No. 18:
[0115] This test illustrates the invention and uses product G
according to the invention.
[0116] From this master batch manufactured with the same operating
method as in the previous test, three samples were taken in which
the calcium carbonates to be tested had been incorporated, by
mixing at 60.degree. C. for 12 minutes.
[0117] After determination of the vulcanisation optima, sheets were
moulded and vulcanised to this optimum in order to effect a
measurement of the mechanical properties according to the same
operating method as for the previous tests.
[0118] The results of the mechanical properties are set out in
Table IV below.
TABLE-US-00008 TABLE IV Test No. Prior art Prior art Invention 16
17 18 Vulcanisation optimum 23 min. 30 s 16 min. 45 s 11 min. at
150.degree. C. Tensile strength (daN/cm.sup.2) 122 132 132 Modulus
300% (daN/cm.sup.2) 16.5 20 20 Elongation % 695 715 695 ASTM-C tear
strength 23 28 28 (daN/cm) Shore A hardness (15 s) 51 50 50 in
(daN/cm)
[0119] It can be seen that the product according to the invention
improves the implementation time (the vulcanisation optimum) and
the majority of the mechanical properties.
EXAMPLE 4
[0120] A second series of tests (Tests 19 and 20) were carried out
in a natural rubber 40 pcr filled with a mineral filler with the
basic formula:
TABLE-US-00009 Natural rubber (smoked sheet quality RSS 1) 100
Coumarone resin 60/70 5.6 Rosin 3 Zinc oxide (snow quality) from
Vieille Montagne 40 Stearic acid 0.5 Oil 4.3 Benzothiazyl
disulphide accelerator 1 (Vulcafor .TM. MBTS from Vulnax)
Diphenylguanidine accelerator 0.36 (Vulcafor .TM. DPG from
Vulnax)
[0121] The calcium carbonates to be tested were:
[0122] Test No. 19:
[0123] A precipitated calcium carbonate (product K) for this test,
which illustrates the prior art.
[0124] Test No. 20:
[0125] A natural calcium carbonate according to the invention
(product G) for this test, which illustrates the invention.
[0126] The results of the mechanical properties, measured with the
same operating method as for the following tests, are set out in
Table V below.
TABLE-US-00010 TABLE V Test No. Prior art Invention 19 20
Vulcanisation optimum at 150.degree. C. 7 min. 15 s 8 min. 15 s
Tensile strength (daN/cm.sup.2) 246 246 Modulus 300% (daN/cm.sup.2)
32 31 Elongation % 710 710 Shore A hardness (15 s) in (daN/cm) 45
46.5
[0127] It can be seen that the product according to the invention
makes it possible to obtain equivalent mechanical property results,
even by completely replacing the precipitated calcium carbonate
with a natural calcium carbonate.
* * * * *