U.S. patent application number 09/164625 was filed with the patent office on 2001-06-07 for thermoplastic fluoropolymer compositions.
Invention is credited to ABUSLEME, JULIO A., STANITIS, GARY, ZOLOTNITSKY, MIKHAIL.
Application Number | 20010003124 09/164625 |
Document ID | / |
Family ID | 11377983 |
Filed Date | 2001-06-07 |
United States Patent
Application |
20010003124 |
Kind Code |
A1 |
ZOLOTNITSKY, MIKHAIL ; et
al. |
June 7, 2001 |
THERMOPLASTIC FLUOROPOLYMER COMPOSITIONS
Abstract
Thermoplastic fluoropolymer compositions, flexible, without
whitening, comprising: I) ETFE or ECTFE fluoropolymers modified
with hydrogenated monomers; II) one or more hydrogenated
plasticizers; III) one or more inorganic fire retardants; IV)
optionally other ingredients such as fillers, smoke retarders,
intumescent agents, pigments, lubricants, organic fire retardants
and thermal stabilizers.
Inventors: |
ZOLOTNITSKY, MIKHAIL;
(JAMISON, PA) ; STANITIS, GARY; (SEWELL, NJ)
; ABUSLEME, JULIO A.; (SARONNO, IT) |
Correspondence
Address: |
ARENT FOX KINTNER PLOTKIN & KAHN
1050 Connecticut Avenue, N. W. Suite 600
Washington
DC
20036-5339
US
|
Family ID: |
11377983 |
Appl. No.: |
09/164625 |
Filed: |
October 1, 1998 |
Current U.S.
Class: |
524/401 ;
524/546; 524/81 |
Current CPC
Class: |
C08K 5/0016 20130101;
C08K 3/01 20180101; C08L 27/12 20130101; C08L 27/12 20130101; C08K
3/01 20180101; C08K 5/0016 20130101 |
Class at
Publication: |
524/401 ; 524/81;
524/546 |
International
Class: |
C08K 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 3, 1997 |
IT |
MI97 A 002253 |
Claims
1. Thermoplastic fluoropolymer compositions, flexible without
whitening, comprising: I) ETFE or ECTFE fluoropolymers modified
with hydrogenated monomers; II) one or more hydrogenated
plasticizers; III) one or more inorganic fire retardants; IV)
optionally other ingredients such as fillers, smoke retarders,
intumescent agents, pigments, lubricants, organic fire retardants
and thermal stabilizers.
2. Compositions according to claim 1 wherein the component I) is a
copolymer formed of: (a) from 10 to 70%, preferably from 35 to 55%,
by moles of ethylene, (b) from 30 to 90%, preferably from 45 to
65%, by moles of a fluorinated monomer selected from
tetrafluoroethylene, chlorotrifluoroethylene, or mixtures thereof,
(c) from 0.1 to 30%, preferably from 1 to 15%, by moles of a
hydrogenated monomer of
formula:CH.sub.2.dbd.CH--(CH.sub.2).sub.n--R.sub.1 (I)where
R.sub.1=--OR.sub.2, --(O).sub.tCO(O).sub.pR.sub.2 wherein t and p
are integers equal to 0 or 1 and R.sub.2 is a hydrogenated radical
from 1 to 20 carbon atoms, C.sub.1-C.sub.20, linear and/or branched
alkyl radical or cyclo-alkyl radical or R.sub.2 is H; the R.sub.2
radical may optionally contain: heteroatoms preferably O, N or a
halogen preferably Cl; one or more functional groups preferably
selected from OH, COOH, epoxide, ester and ether; and double bonds;
the above mentioned n is an integer in the range 0-10; preferably
R.sub.2 is an alkyl radical from 1 to 10 carbon atoms containing
one or more hydroxy functional groups and n is an integer in the
range 0-5; the components II) are well known hydrogenated
plasticizers used in the hydrogenated (co)polymers, from 1 to 20%
by weight, preferably from 5 to 10% by weight; the components III)
are the inorganic fire retardants from 0.2 to 35% by weight,
preferably from 1 to 15% by weight; the components IV) are
ingredients from 0.1 to 15% by weight, preferably from 0.5 to 5% by
weight.
3. Compositions according to claim 2 wherein the comonomers (c) of
the component I) are selected from: 1) acrylic monomers having the
formula:CH.sub.2.dbd.CH--CO--O--R.sub.2 wherein R.sub.2 has the
aforesaid meaning; 2) vinylether monomers having the
formula:CH.sub.2.dbd.CH--O--R.- sub.2 wherein R.sub.2 has the
aforesaid meaning; 3) vinyl monomers of the carboxylic acid of
formula:CH.sub.2.dbd.CH--O--CO--R.sub.2 wherein R.sub.2 has the
aforesaid meaning; 4) unsaturated carboxylic acids of
formula:CH.sub.2.dbd.CH--(CH.sub.2).sub.n--COOHwherein n has the
aforesaid meaning.
4. Compositions according to claims 2-3 wherein the comonomers (c)
of the component I) are selected from: ethylacrilate,
n-butylacrilate, acrylic acid, hydroxyethylacrylate,
hydroxypropylacrylate, (hydroxy)ethylhexylacrylate;
propylvinylether, cyclohexylvinylether, vinyl-4-hydroxybutylether;
vinylacetate, vinylpropionate, vinyl-2-ethylhexanoate; vinylacetic
acid.
5. Compositions according to claims 2-4, wherein the preferred
monomer of formula (I) is n-butyl acrylate.
6. Compositions according to claims 1-5 wherein the component II),
the hydrogenated plasticizers, are selected from:
2-ethylhexyldiphenylphospha- te, neopentyl glycoldibenzoate,
tricresylphosphate, tetrabromophthalic ester, tri
n-hexyl-trimellitate, ethylene glycol monostearate, acetyl
tri-n-hexyl citrate; preferably acetyl tri-n-butyl citrate,
tributyl trimellitate and tri-n-hexyltrimellitate.
7. Composition according to claims 1-6, wherein the component III),
the inorganic fire retardants, are selected from: inorganic
phosphates (ammonium phosphate), metal oxides (aluminum oxide,
aluminum oxide tri-hydrate, antimonium oxides, molybdenum oxide),
tin oxalates, boron compounds (borax, zinc borate, Firebrake.RTM.
ZB), metal hydroxide (magnesium hydroxide, or hydroxide mixture
preferably Zn(OH).sub.2 and Sn(OH).sub.4).
8. Compositions according to claims 1-7 wherein the component IV)
are polytetrafluoroethylene (PTFE), mica, metal oxide coated mica
and mica blended with metal oxides or mixture thereof.
9. Compositions according to claims 7-8 wherein the inorganic fire
retardants are treated with dispersing agents in amounts ranging
from 0.01 to 10% by weight, more preferably from 0.1 to 5% by
weight.
10. Compositions according to claims 6-9 wherein one or more of the
inorganic compounds of the component IV) are treated with
dispersing agents in amount ranging from 0.01 to 10% by weight,
more preferably from 0.1 to 5% by weight.
11. Compositions according to claims 9-10 wherein the dispersing
agents have formula:(R.sub.3).sub.4-mA(X).sub.m (II)wherein m is an
integer from 1 to 3, A is Si or Ti or Zr and X is an hydrolyzable
group, R.sub.3 is an oligomer of hydrogenated monomers or
C.sub.1-C.sub.15 alkyl and/or aryl radical; the R.sub.3 radical
optionally containing: unsaturations; one or more heteroatoms
selected from: O, N, S, or halogen such as Cl; functional groups
like amine, epoxide, thio group (--SH), hydroxide, carboxyl and
carboxylate.
12. Compositions according to claim 11, wherein the dispersing
agents, in a monomeric or oligomeric form, have m=2 or 3; X is a
hydrolyzable group, preferably x is an alkoxy group OR.sub.4 in
which R.sub.4 is a C.sub.1-C.sub.5 linear or branched alkyl
radical; preferably A is Si and/or Ti; when A is equal to Si
preferably m=3 and R.sub.4 is methyl or ethyl.
13. Compositions according to claims 11-12 wherein the dispersing
agents are selected from: vinyltriethoxysilane,
3-aminopropyltriethoxysilane, 3-chloroisobutyltriethoxysilane,
3-mercaptopropyltriethoxysilane, octyltriethoxysilane,
bisacetylacetonate diisopropoxytitanate.
14. Compositions according to claims 9-13 wherein the addition of
the dispersing agent to the inorganic fire retardants and/or to one
or more inorganic compounds of the component IV) is preferably
carried out at room temperature and then thermally treated at about
100.degree. C. for one or more hours, the water required for the
hydrolysis of the dispersing agents comes from the reaction medium
and/or from the solution containing the dispersing agents, or from
the environment.
Description
[0001] The present invention relates to thermoplastic fluoropolymer
compositions for the plenum wire insulation and cable jacketing
applications, that show a high time to ignition, a low smoke and
heat release when put in contact with a heat source as for example
in the Cone Calorimeter (see the ASTM E1354 test).
[0002] More in particular the present invention relates to
thermoplastic compositions of fluoropolymers of ethylene with
tetrafluoroethylene (ETFE) and/or chlorotrifluoroethylene (ECTFE),
modified with one or more hydrogenated monomers.
[0003] The copolymers of ethylene and a fluorinated monomer such as
tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE), or both,
are known in the art. It is also known the possibility to modify
them with fluorinated unsaturated monomers in an amount between 0.1
and 10% by moles. For example we mention the
(per)fluoroalkylvinylethers in which the alkyl group has at least
two carbon atoms, in particular the perfluoropropylvinylether (see
U.S. Pat. No. 3,624,250). Other possible comonomers have the
formula R'--CH.dbd.CH.sub.2, where R' is a perfluoroalkyl or a
perfluoroalkoxy-perfluoroalkyl (see EP 185, 241, EP 185, 242)
[0004] The above mentioned ETFE and ECTFE copolymers non modified
with fluoroolefins have poor affinity with hydrogenated substances,
these being polymers or high molecular weight compounds (for
example plasticizers).
[0005] In EP 728,776 a special fluoroolefin able to copolymerize
with fluorinated olefins giving for example a modified ETFE, is
disclosed. This polymer shows good affinity with hydrogenated
polymers, in particular with aromatic polyesters.
[0006] In general the syntheses of special fluoroolefins are
complex and therefore they are used as comonomers in ethylene
fluoropolymers only when high performances are required. For
example good chemical resistance combined with excellent mechanical
properties at high temperatures (150.degree.-200.degree. C.).
[0007] The preparation of fluoropolymers blended with one or more
plasticizers to make the fluoropolymers flexible and usable in the
cable industry has a particular industrial interest. These polymers
must be characterized by the absence of the whitening phenomenon
when the cable is bended.
[0008] The whitening effect must be avoided because it visually
represents the plastic deformation of the material, and due to this
it cannot recover the initial state. The electrical properties
required for this material are fully satisfied by the ECTFE which
unfortunately has a high elastic modulus at room temperature, in
general higher than 1500 MPa and therefore it is not flexible.
[0009] In addition the ECTFE has a stress-strain curve at room
temperature characterized by a necking at yield that makes it
sensitive to the whitening effect on the bended cable. The elastic
modulus of ECTFE can be lowered by adding plasticizers, but in any
case the material suffers of the whitening effect.
[0010] The Applicant, in order to overcome this problem, as
disclosed in EP 866,079, has proposed the use of ETFE or ECTFE type
fluoropolymers modified with hydrogenated monomers blended with
plasticizers, having high flexibility and that do not show the
whitening phenomenon.
[0011] However for safety reasons these flexible cables must show a
high time to ignition, a low smoke and heat release when put in
contact with a heat source, as for example in the Cone Calorimeter
(see the ASTM E1354 test).
[0012] Unfortunately the presence of plasticizers increases the
smoke and heat release.
[0013] The Applicant has found that when using fire retardants in
the polymers compounded with plasticizers, it is possible to obtain
flexible compositions having the following combination of
properties:
[0014] good mechanical properties,
[0015] absence of the whitening effect,
[0016] decrease of smoke and heat release when tested in a Cone
Calorimeter according to the ASTM E1354 test.
[0017] An object of the present invention is a composition
comprising:
[0018] I) ETFE or ECTFE fluoropolymers modified with hydrogenated
monomers;
[0019] II) one or more hydrogenated plasticizers;
[0020] III) one or more inorganic fire retardants;
[0021] IV) optionally other ingredients such as fillers, smoke
retarders, intumescent agents, pigments, lubricants, organic fire
retardants and thermal stabilizers.
[0022] More in particular the component I) of the compositions of
the invention is a copolymer formed of:
[0023] (a) from 10 to 70%, preferably from 35 to 55%, by moles of
ethylene,
[0024] (b) from 30 to 90%, preferably from 45 to 65%, by moles of a
fluorinated monomer selected from tetrafluoroethylene,
chlorotrifluoroethylene, or mixtures thereof,
[0025] (c) from 0.1 to 30%, preferably from 1 to 15%, by moles of a
hydrogenated monomer of formula:
CH.sub.2.dbd.CH--(CH.sub.2).sub.n--R.sub.1 (I)
[0026] where R.sub.1=--OR.sub.2, --(O).sub.tCO(O).sub.pR.sub.2
wherein t and p are integers equal to 0 or 1 and R.sub.2 is a
hydrogenated radical from 1 to 20 carbon atoms, C.sub.1-C.sub.20,
linear and/or branched alkyl radical, or cycloalkylic radical, or
R.sub.2 is H. The R.sub.2 radical can optionally contain:
heteroatoms preferably O, N; halogens preferably Cl; one or more
functional groups, preferably selected from OH, COOH, epoxide,
ester and ether; and double bonds. The above mentioned n is an
integer in the range 0-10.
[0027] Preferably R.sub.2 is an alkyl radical from 1 to 10 carbon
atoms optionally containing one or more hydroxy functional groups,
n is an integer in the range 0-5.
[0028] The preferred comonomers (c) are for example selected from
the following classes:
[0029] 1) Acrylic monomers of formula:
CH.sub.2.dbd.CH--CO--O--R.sub.2
[0030] wherein R.sub.2 has the aforesaid meaning.
[0031] For example ethylacrylate, n-butylacrylate, acrylic acid,
hydroxyethylacrylate, hydroxypropylacrylate,
(hydroxy)ethylhexylacrylate, etc., can be mentioned.
[0032] 2) Vinylether monomers of formula:
CH.sub.2.dbd.CH--O--R.sub.2
[0033] wherein R.sub.2 has the aforesaid meaning.
[0034] For example propylvinylether, cyclohexylvinylether,
vinyl-4-hydroxybutylether, etc., can be mentioned.
[0035] 3) Vinyl monomers of the carboxylic acid of formula:
CH.sub.2.dbd.CH--O--CO--R.sub.2
[0036] wherein R.sub.2 has the aforesaid meaning.
[0037] For example vinyl-acetate, vinylpropionate,
vinyl-2-ethylhexanoate, etc., can be mentioned.
[0038] 4) Unsaturated carboxylic acid of formula:
CH.sub.2.dbd.CH--(CH.sub.2).sub.n--COOH
[0039] wherein n has the aforesaid meaning. For instance
vinylacetic acid, etc.
[0040] The most preferred monomer of formula (I) is n-butyl
acrylate.
[0041] Components II) are hydrogenated plasticizers well known in
the art and used in the hydrogenated (co)polymers, from 1 to 20% by
weight, preferably from 5 to 10% by weight referred to the total
weight of the composition.
[0042] Examples of plasticizers, not limitative for the present
invention, are: 2-ethylhexyldiphenylphosphate, neopentyl
glycoldibenzoate, tricresylphosphate, tetrabromophtalate ester,
tri-n-hexyl-trimellitate, ethylene glycol monostearate,
acetyltri-n-hexyl citrate; preferably acetyltri-n-butyl citrate
(Citroflex.RTM. A4), tributyl trimellitate and
tri-n-hexyltrimellitate.
[0043] Components III) are the inorganic fire retardants used in
amounts from 0.2 to 35% by weight, preferably from 1 to 15% by
weight, referred to the total weight of the composition.
[0044] The fire retardants are well known in the art of
hydrogenated (co)polymers. We can mention for example: inorganic
phosphates (for example, ammonium phosphate), metal oxides (for
example, aluminum oxide, aluminum oxide trihydrate, antimony
oxides, molybdenum oxide), tin oxalates, boron compounds (for
example, borax, zinc borate, Firebrake.RTM. ZB), metal hydroxide
(for example, magnesium hydroxide, or hydroxide mixture such as
Zn(OH).sub.2 and Sn(OH).sub.4 e.g. ZnSn(OH).sub.6).
[0045] Components IV) are used in amounts from 0.1 to 15% by
weight, preferably from 0.5 to 5% by weight, referred to the total
weight of the composition.
[0046] The optional ingredients are fillers (for example,
polytetrafluoroethylene (PTFE), silicates, mica, metal oxide coated
mica, mica blended with metal oxides), smoke retarders, lubricants,
pigments, organic fire retardants (for example, halogenated
compounds as chloroparaffins, brominated polyesters, brominated
epoxy oligomers); intumescent agents and thermal stabilizers as,
for example, Irganox.RTM. 1010.
[0047] Furthermore the Applicant has surprisingly found that the
use of inorganic fire retardants treated with dispersing agents
with respect to the simple addition of inorganic fire retardants to
the plasticized ETFE or ECTFE fluoropolymer type modified with
hydrogenated monomers, leads to a further unexpected increase of
the time to ignition and to a further substantial decrease of smoke
and heat release according to the ASTM E1354 test run in a Cone
Calorimeter.
[0048] Therefore a further object of the present invention is the
use of inorganic fire retardants treated with dispersing agents as
hereinafter described.
[0049] The inorganic fire retardants are treated with dispersing
agents in amounts ranging from 0.01 to 10% by weight, more
preferably from 0.1 to 5% by weight.
[0050] Optionally, the inorganic components IV) of the composition
can be treated with dispersing agents in an amount ranging from
0.01 to 10% by weight, more preferably from 0.1 to 5% by weight.
For example fillers (e.g. mica) treated together with the fire
retardants or singly with dispersing agents.
[0051] The dispersing agents according to the present invention are
those known in the art to disperse fillers and that satisfy one of
the following tests:
[0052] Test 1: any substance able to disperse inorganic fillers
like silica, for example cristobalite, having at least 95% of the
particles with average diameter of 2 .mu.m, in solvents like methyl
methacrylate. A dispersion is a system in which the particles of
the filler are dispersed in the solvent or easily redispersable
after segregation;
[0053] Test 2: any substance able to homogeneously disperse the
inorganic fire retardants and/or the inorganic components IV) in
another solid phase of known particle size distribution. The degree
of dispersion, can be estimated by a visual analysis of a tablet of
the dispersion using a coloured solid matrix.
[0054] The preferred dispersing agents according to the present
invention have formula:
(R.sub.3).sub.4-mA(X).sub.m (II)
[0055] wherein m is an integer from 1 to 3, A is Si or Ti or Zr and
X is a hydrolyzable group, R.sub.3 is an oligomer of hydrogenated
monomers or a C.sub.1-C.sub.15 alkyl and/or aryl radical. The
R.sub.3 radical can contain: unsaturations; one or more heteroatoms
selected from: O, N, S, or halogens such as Cl; functional groups
such as amine, epoxide, thio group --SH, hydroxide, carboxyl and
carboxylate.
[0056] Among these, the preferred dispersing agents, in a monomeric
or oligomeric form, are those wherein m is 2 or 3; X is a
hydrolyzable group where X is preferably an alkoxy group OR.sub.4
in which R.sub.4 is a C.sub.1-C.sub.5 linear or branched alkyl
radical, preferably R.sub.4 is methyl or ethyl; R.sub.3 and A are
as above defined. Preferably A is Si and/or Ti. When A is equal to
Si preferably m=3 and R.sub.4 is methyl or ethyl.
[0057] For example we can mention: vinyltriethoxysilane,
3-aminopropyltriethoxysilane, 3-chloroisobutyltriethoxysilane,
3-mercaptopropyltriethoxysilane, octyltriethoxysilane,
bisacetylacetonate diisopropoxytitanate.
[0058] As examples of oligomeric form of dispersing agents
according to the formula (II) we can mention those of silane A-174.
In the case R.sub.3 is formed by hydrogenated monomers, we can
mention, for example, the acrylic acid esters.
[0059] The addition of the dispersing agents to the inorganic fire
retardants and to the inorganic component IV) is preferably carried
out at room temperature and followed by a thermal treatment at
about 100.degree. C. for one or more hours. The water required for
the hydrolysis of the dispersing agents comes from the reaction
medium and/or from the solution containing one or more dispersing
agents, or from the environment.
[0060] The following examples are given for illustrative purposes
but are not limitative of the present invention.
[0061] In Table 1 the tests have been carried out according to the
ASTM E1354 method for the time to ignition; heat and visible smoke
release rates for materials and products using an Oxygen
Consumption Calorimeter; Radiant Heat Flux 90 Kw/m.sup.2; sample
weight 50 g; horizontal sample direction.
EXAMPLE 1
[0062] In an enamelled autoclave equipped with baffles and stirrer
working at 450 rpm in Hastelloy C, 7 l of demineralized water, 15.5
g of chloroform, 10 g of n-butylacrylate and 2 kg of
chlorotrifluoroethylene were introduced. The temperature reaction
was set and maintained at 15.degree. C. Then ethylene was charged
up to a pressure of 8.2 absolute bars. In the autoclave the radical
initiator was then continuously introduced during the whole
polymerization time, under the form of a solution, maintained at
-17.degree. C., of trichloroacetyl-peroxide (TCAP) in isooctane
with titre of 0.1 g TCAP/ml. In addition 10 g of n-butylacrylate
were charged to the reactor at consumption of 20, 40, 60, 80, 100,
120, 140, 160 and 180 g of ethylene.
[0063] The pressure was maintained constant for the whole
polymerization by continuously feeding ethylene in the reactor up
to a consumption of 200 g; the total amount of initiator solution
was of 210 ml. The polymerization lasted 405 minutes.
[0064] Then the polymer produced was dried at 120.degree. C. for
about 16 hours. The total dry weight was of 1530 g.
[0065] The polymer was then compounded with MARK-260.RTM. 0.45% by
weight and Aclyn-316.RTM. 0.15% by weight both mainly used as
thermal stabilizers.
[0066] Some characteristics of this polymer (defined Polymer A) are
the following: the Melt Flow Index (M.I.) according to ASTM 3275-89
method is of 9 g/10'; the second melting point (T.sub.mII)
determined by Differential Scanning Calorimetry (DSC) is
190.degree. C. and the molar composition obtained by carbon
elemental analysis and by material balance is ethylene 40% by
moles, chlorotrifluoroethylene 55% by moles and n-butylacrylate 5%
by moles.
EXAMPLE 2 (COMPARATIVE)
[0067] The polymer powder A has been blended with Citroflex.RTM. A4
in an amount equal to 7% by weight based on the blend. Then the
blend has been pelletized in a twin-screw extruder. This compound
has been tested in a Cone Calorimeter according to the ASTM E1354
method. Table 1 reports time to ignition, peak heat release rate,
total heat released and average extinction coefficient related to
the smoke for a sample of 50 g by weight.
EXAMPLE 3
[0068] The polymer powder A blended with Citroflex.RTM. A4 as in
Example 2 has been compounded with zinc borate (Firebrake.RTM. ZB
500) 5% by weight and mica 1% by weight based on the total weight.
Then the blend has been pelletized in a twin-screw extruder. This
compound has been tested in a Cone Calorimeter according to the
ASTM E1354 method. Table 1 reports time to ignition, peak heat
release rate, total heat released and average extinction
coefficient related to the smoke for a sample of 50 g by
weight.
EXAMPLE 4
[0069] As in Example 3 except that zinc borate and mica are blended
with 2% by weight of water-borne-3-aminopropyl-triethoxysilane, and
then thermally treatment at 100.degree. C. for two hours. Then the
blend has been pelletized in a twin-screw extruder. This compound
has been tested in a Cone Calorimeter according to the ASTM E1354
method. Table 1 reports time to ignition, peak heat release rate,
total heat released and average extinction coefficient related to
the smoke for a sample of 50 g by weight.
EXAMPLE 5
[0070] As in Example 3 except that zinc borate and mica are blended
with 2% by weight of a solution formed by 75% by weight of
bisacetylacetonate diisopropoxytitanate and 25% by weight of
isopropanol, and then thermally treated at 100.degree. C. for two
hours. Then the blend has been pelletized in a twin-screw extruder.
This compound was tested in a Cone Calorimeter according to the
ASTM E1354 method. Table 1 reports time to ignition, peak heat
release rate, total heat released and average extinction
coefficient related to the smoke for a sample of 50 g by
weight.
[0071] The mechanical properties at 23.degree. C. according to the
ASTM D1708 test of compression moulded specimen of the compound are
shown in Table 2.
EXAMPLE 6
[0072] As in Example 3, except that zinc borate and mica are
blended with 2% by weight of a solution formed by 75% by weight of
bisacetylacetonate diisopropoxytitanate and 25% by weight of
isopropanol and with 2% by weight of water-borne
3-aminopropyltriethyoxysilane, and then thermally treated at
100.degree. C. for two hours. Furthermore, 1% by weight of PTFE
(POLYMIST.RTM.) has been added to the compound and then pelletized
in a twin-screw extruder.
[0073] This compound has been tested in a Cone Calorimeter
according to the ASTM E1354 method. Table 1 reports time to
ignition, peak heat release rate, total heat released and average
extinction coefficient related to the smoke for a sample of 50 g by
weight.
[0074] The mechanical properties at 23.degree. C. according to the
ASTM D1708 test of compression moulded specimen of the compound are
shown in Table 2.
[0075] From Tables 1 and 2 it can be observed that the compositions
of the invention are characterized by having good mechanical
properties, they are flexible, they do not show the whitening
effect and they have excellent flame-retardant and smoke-suppressed
properties.
1TABLE 1 Cone Calorimeter data according to the ASTM E1354 method.
Radiant Heat Flux 90 Kw/m.sup.2. Horizontal orientation of the
sample. Average extinction Time to Peak heat Total heat coefficient
ignition release rate released (smoke) Examples sec. Kw/m.sup.2
MJ/m.sup.2 m.sup.2/g Example 2 (comp) 16 203 25,3 0,631 Polymer A
(P) Example 3 15 141,6 24,3 0,525 Polymer A (P,FR) Example 4 210
41,3 12,4 0,139 Polymer A (P,SiFR) Example 5 220 40,7 12,9 0,124
Polymer A (P,TiFR) Example 6 196 32,6 12,8 0,114 Polymer A
(P,L,SiTiFR) P = blended with plasticizer Citroflex .RTM. A4 L =
blended with PTFE (POLYMIST .RTM.) FR = blended with mica and zinc
borate SiFR = blended with mica and zinc borate treated with
silanate TiFR = blended with mica and zinc borate treated with
titanate SiTiFR = blended with mica and zinc borate treated with
silanate and titanate
[0076]
2TABLE 2 Mechanical Example 5 Example 6 properties Polymer A
Polymer A 23.degree. C. (P,TiFR) (P,L,SiTiFR) Elastic 270 280
modulus (MPa) Stress 10 10 at yield (MPa) Elongation (*) (*) at
yield (%) Stress 27 28 at break (MPa) Elongation 260 270 at break
(%) (*) It cannot be determined because of the absence of the
necking at yield in the stress-strain curve P = blended with
plasticizer Citroflex .RTM. A4 L = blended with PTFE (POLYMIST
.RTM.) TiFR = blended with mica and zinc borate treated with
titanate SiTiFR = blended with mica and zinc borate treated with
silanate and titanate
* * * * *