Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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HIGH-CONCENTRATION CROSS-LINKING MASTERBATCHES
The present invention relates to cross-linking masterbatches, more
particularly
to masterbatches to be used for the cross-linking of (elastomeric)
thermoplastics and rubbers.
Thermoplastics, elastomeric thermoplastics, and rubbers, elastomers for short,
include preferred products such as polyethylene, ethylene-vinyl acetate
copolymer, ethylene-propylene copolymer (EPM), ethylene-octene copolymer
(POE), ethylene-propylene diene rubber (EPDM), and butadiene-acrylonitrile
copolymer, all of which are low-priced, widely available, and have excellent
physical properties that allow wide-ranging use. The elastomers can be cross-
linked in a conventional way by heating in the presence of an appropriate
organic peroxide, e.g., to increase their heat resistance.
When cross-linking elastomers, it is preferred, from an economic point of
view,
to mix pure organic peroxide with the elastomer. However, such a procedure
often is not feasible in view of safety considerations. Also, it is known that
the
use of such pure organic peroxide leads to a less homogeneous distribution in
the elastomer to be cross-linked, resulting in an unevenly cross-linked
product
with inferior properties, especially compared to a process where the
elastomers
are mixed with organic peroxides formulated with inactive fillers such as
calcium
carbonate, silica, clay, and talc, or with a polymer or elastomer (so-called
masterbatches), in the form of sheets or granules. Therefore, in industry
generally powdery formulations and masterbatches in the form of sheets or
granules are used.
Powdery formulations where the organic peroxide is diluted with inactive
fillers
have the following advantages when used as a cross-linking agent:
(1) they are safe to store and handle,
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(2) because they are powders, they can be metered into the elastomer in a
simple manner, irrespective of the organic peroxide (solid or liquid) used,
and
(3) they are inexpensive.
However, these powdery formulations suffer from the following disadvantages:
(1) It typically takes too long to obtain a homogenous dispersion of the
peroxide in the elastomers to be cross-linked,
(2) the formulations tend to be dusting, leading to exposure of operators to
dust during the metering of the formulation and while it is being kneaded
with the elastomers to be cross-linked.
Masterbatches in the sheet or granular form, where the peroxide is dispersed
in
a polymer, preferably an elastomer, have the same benefits as powdery
formulations. Additionally, they require less time to prepare homogeneous
dispersions of the peroxide in the elastomer to be cross-linked and can be
handled without dust being formed. Therefore, such (sheet or granular-type)
masterbatches often are the product of choice for processes where a peroxide
and an elastomer are to be intimately mixed.
However, sheet or granular-type masterbatches typically suffer from the fact
that highly concentrated products cannot be formed. Where commercial
powdery formulations are known to contain 50% by weight of peroxide,
commercial sheet or granular-type masterbatches are limited to formulations
containing 40% by weight of peroxide.
Conventional cross-linking masterbatches containing up to 40% by weight of
organic peroxide, EPM or EPDM, and wet-treated or dry-treated silica as
essential ingredients are known to be produced in a conventional way, e.g., on
an open roll mixer, by kneading said ingredients, optionally with inactive
fillers
such as calcium carbonate added. The physical state of the organic peroxide,
the properties of the EPM or EPDM (such as Mooney viscosity, ethylene or
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propylene content), and the properties of the wet- or dry-treated silica (such
as
specific surface area and oil absorption capacity) are not important in such a
case. The wet- or dry-treated silicas used for this purpose have a specific
surface area of 40-140 m2/g and a pore volume of 0.1-0.6 ml/g.
However, if a masterbatch containing more than 40% by weight of a liquid
organic peroxide is to be produced by kneading said peroxide with EPM or
EPDM and such conventional dry- or wet-treated silica on a roll mill, the
masterbatch tends to stick to the roll, making mixing more difficult, is
difficult to
remove from the roll in (thin) sheets, and results in sheets of inferior
strength.
Furthermore, it was found that the resulting sheets or granules are not
storage
stable. More specifically, they suffer from exudation of the peroxide from the
masterbatch.
Similarly, if the masterbatch contains more than 40% by weight of solid
organic
peroxide, the mass on the rolls easily breaks up on the roll during kneading,
making it difficult to knead the product efficiently. The resulting
masterbatch
was found to suffer from blooming of the peroxide from the masterbatch.
To overcome these problems, W098/54249 discloses the production process of
a high concentration masterbatch which essentially contains liquid polymers
such as EPM/EPDM having Brookfield viscosity at 60°C of 10,000 mPas and
lower. However, these liquid polymers are expensive, which is considered to be
the main reason why they have not gained wide market acceptance.
Accordingly, there is still a need for peroxide masterbatches, especially EPM
and/or EPDM based masterbatches, containing more than 40% by weight of
either liquid or solid peroxide that do not dust, are easy to handle and
storage
stable, do not contain expensive low-molecular weight polymers, and lead to a
homogeneous distribution in the elastomer to be cross-linked.
The high-concentration cross-linking masterbatches of the present invention
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were found to solve these problems. They are characterized in that they
contain
a solid synthetic rubber, such as EPM and/or EPDM, as the base polymer, from
40 to 70% by weight of an organic peroxide, and a specific silica. More
preferably, the masterbatches of the invention contain from 40 to 70% by
weight of organic peroxide and an EPM and/or EPDM rubber of which the
propylene content is 35% by weight or more, preferably 40% by weight or more,
more preferably at least 45% by weight, and a Mooney viscosity, determined
from the ML 1+4 at 100°C, as is conventional in the art, of 30 or more.
The
specific silica that is to be used can be characterized by (a) its specific
surface
area of at least 150 m2/g if the organic peroxide is solid at ambient
temperature,
or (b) its pore volume of at least 1.4 ml/g, preferably 1.5 ml/g or more, if
the
organic peroxide is a liquid at ambient temperature.
Accordingly, the present invention relates to:
(1) A cross-linking masterbatch containing at least one organic peroxide in
an amount of from 40 to 70 % by weight, based on the weight of the total
masterbatch, at least one synthetic rubber, and a silica having a specific
surface area of 150 m2/g or more or a pore volume of 1.4 ml/g or more.
(2) A high-concentration cross-linking masterbatch according to (1) above,
wherein said masterbatch contains the dry-treated or wet-treated silica
with (a) a specific surface area of 150 m2/g or more if said organic
peroxide is solid at ambient temperature, or (b) a pore volume of 1.4 ml/g
or more if said organic peroxide is liquid at ambient temperature.
(3) A high-concentration cross-linking masterbatch according to (1) or (2)
above, wherein said synthetic rubber is an ethylene-propylene rubber or
an ethylene-propylene-diene rubber of which the propylene content is
45% or more and the Mooney viscosity at 100°C is 30 or more.
(4) A high-concentration cross-linking masterbatch according to (1) to (3)
above, wherein said organic peroxide is present in an amount of from 40
to 65% by weight, said synthetic rubber is present in an amount of from
10 to 30% by weight, and said silica is present in an amount of from 5 to
30% by weight, each based on the weight of the total masterbatch.
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Preferred organic peroxides for use in the present invention have a 10 hr half-
life temperature of 60°C or more and are liquid or solid at ambient
temperature.
Ambient temperature here means about 15°C-30°C, depending
on the region,
5 season, and working environment. The term "10 hr half-life temperature" is
used in the conventional way, meaning the temperature at which 50% of the
peroxide decomposes in 10 hours time when measured by thermal
decomposition of a 0.2 mol/I solution of the peroxide in monochlorobenzene.
Preferred organic peroxides that are solid at ambient temperature include
dialkyl peroxides, such as dicumyl peroxide, 1,3-bis(tert-
butylperoxyisopropyl)
benzene, and 1,4-bis (tert-butylperoxyisopropyl)benzene, and diacyl peroxides
such as dibenzoyl peroxide.
Preferred organic peroxides that are liquid at ambient temperature include
dialkyl peroxides, such as 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5
dimethyl-2,5-di(tert-butylperoxy)hexyne-3, tert-butyl cumyl peroxide, di-tert-
butyl
peroxide, and di-tert-amyl peroxide; peroxyketals such as 1,1-di-tert
butylperoxy-3,3,5-trimethyl cyclohexane, 4,4-di-tert-butylperoxy valeric acid
n
butyl ester, and 1,1-di-tert-butylperoxy cyclohexane.
Of these organic peroxides, the more preferred ones for use in the master-
batches according to the invention include dicumyl peroxide, 1,3-bis(tert-
butylperoxyisopropyl) benzene, and 1,4-bis (tert-butylperoxyisopropyl)
benzene,
2,5-dimethyl-2,5-di(tert-butylperoxy) hexane, 1,1-di-tert-butylperoxy-3,3,5
trimethyl cyclohexane, and 4,4-di-tert-butylperoxy valeric acid n-butyl ester.
The organic peroxides can be used individually or as a mixture of one or more
peroxides. A mixture can be handled either as a liquid or as a solid,
depending
on its physical form at ambient temperature. The cross-linking masterbatch of
the present invention may contain any of these organic peroxides in a total
peroxide concentration of from 40 to 70% by weight, preferably from 42.5 to
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65% by weight, even more preferably 45 to 62.5% by weight, and most
preferably from 47.5 to 60% by weight.
Preferred synthetic rubbers for use in the present invention are EPM and
EPDM. They are ethylene-propylene copolymer and ethylene-propylene-diene
terpolymer, respectively, of which the Mooney viscosity (ML1+4 100°C)
is 30 or
more and the propylene content is 35% or more, preferably 40% or more, more
preferably 45% or more. Although neither the Mooney viscosity nor the
propylene content has its respective upper limits, generally available EPM and
EPDM have a Mooney viscosity (ML 1+4 100°C) of about 20-150 and a
propylene content of about 20-50%. However, in the masterbatches of the
present invention EP(D)M having a higher Mooney viscosity and/or higher
propylene content can be used as well. Other preferred elastomers for use
according to the present invention are ethylene-vinyl acetate copolymer, and
ethylene octene copolymers (POE's), such as Engaged ex Dupont Dow
Elastomers. Preferably the POE has a high octene content.
In the masterbatches of the present invention use may be made of any silica
fulfilling the specific surface area and/or pore volume criteria. Wet-treated
silica,
being silica that is precipitated from an aqueous phase, which includes
essentially all conventional precipitated silicas as well as silicates, and
dry-
treated silica, being silica that is pyrogenic in nature. Examples of wet-
treated
silica are NipsiINS-PT"~, NipsiIVN-3TM, NipsiINS-KTM (made by Nihon Silica),
MizukasilP-802T"", MizukasilP-554AT~" (made by Mizusawa Chem. Ind.),
FinesilE50T"", FinesiIT32T"~, FindsiIX37T"", FinesiIX80T"~, FinesilK41 T""
(made by
Tokuyama), Sipernat 22T"", Sipernat 50ST"", Sipernat 50T"', FK500LST"",
FK700T"" (made by Degussa), Ketjensil SM660T"~, Ketjensil SM614T"", Ketjensil
SM611 T"~ (made by Akzo-PQ), Hi-Si1132T"", and Hi-Si1135T"" (made by PPG).
Examples of dry-treated silica are Aerosi1200T"', Aerosi1300T"", Aerosi1380T""
(made by Nihon Aerosil). The most preferred silica for use in the invention
has
a specific surface area of 200 m2lg or more.
Preferred porous silicas (silica gel) have a pore volume of 1.5 ml/g or more,
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such as Mizukasil P-707T"", Mizukasil P-740T"", Mizukasil P-78FT"~, Mizukasil
P-
78DT"', Mizukasolb C-IT"", Mizukasolb C-6T"" (made by Mizusawa Chem. Ind.),
Silicia 250T"", Silicia250NT"', Silicia 256T"~, Silicia 256NT"~, Silicia
310T"", Silicia
320T"", Silicia 350T"',Silicia 358T"~ (made by Fuji Silicia). The (porous)
silica is
generally used in a powdery state, the preferable average particle size being
about 1-15 Vim.
Also silica that has been treated to make it more hydrophobic, e.g. by means
of
a treatment with methylchlorosilane, can be used, provided it has the specific
surface area and/or pore volume. One specific kind or type of silica can be
used. However, also mixtures of various silicas are suitable, as long as the
final
mixture of silicas has the required specific surface area and/or pore volume.
The specific surface area and the pore volume of the silica are determined in
a
conventional way by measuring the N2 isothermal absorption line in accordance
with the BET method (as in DIN 66131).
Wet-treated silica has small holes due to the agglomeration of particles. In
the
determination of the pore volume both these holes between the particles and
the pores of the silica are analyzed. It was found that, irrespective of the
true
pore volume, any wet-treated silica is suitable as long as the BET analysis
shows a pore volume of at least 1.4 ml/g, more preferably of at least 1.5
ml/g.
Although the present invention imposes no upper limit on the specific surface
area and the pore volume of the silica, a practical limit may be found in the
commonly available silicas. At present, a practical upper limit for the
specific
surface area and the pore volume appears to be about 700 m2/g and about 1.8
ml/g, respectively. However, if available, also silicas having a higher
specific
surface area, e.g. up to 1,000 m2/g, and a higher pore volume, e.g. up to 2.0
ml/g, can be used.
In order to be able to make masterbatches with the highest possible organic
peroxide concentration, the specific surface area and pore volume should be as
high as possible. Therefore, it is preferred to use silicas with a specific
surface
area of at least 200 m2/g andlor an pore volume of at least 1.5 ml/g,
preferably
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at least 1.6 ml/g.
The high-concentration cross-linking masterbatch of the present invention
containing organic peroxide, synthetic rubber, and silica may additionally
contain one or more conventional inorganic fillers (as commonly used in the
elastomer processing process), as long as these fillers do not adversely
affect
the performance and storage stability of the masterbatch. Preferred inorganic
fillers are precipitated calcium carbonate, heavy calcium carbonate, talc,
clay,
and carbon black. Their surfaces may be treated with fatty acid, silane-type
coupling agent, and other compounds.
The masterbatches of the present invention may further contain one or more
adjuvants selected from the group of antioxidants, UV stabilizers, flame
retardants, pigments, dyes, processing oils, lubricants, and other additives
that
are commonly used in elastomers. These products are to be used in the
conventional amounts, provided that they do not adversely affect the
performance and storage stability of the masterbatch. Typically, they
constitute
5% by weight or less of the total masterbatch.
The cross-linking masterbatch of the present invention may be produced by
mixing the above ingredients in any suitable way. Typically, use is made of an
open roll mill, a Banbury mixer, a kneader, an extruder, or a transfer mixer,
which equipment is commonly used for elastomer processing. The preferred
mixer is an open roll mill. In order to produce sheets or granules of the
masterbatch of the present invention, a pelletizer, a cutter, and similar
equipment can be added to the mixer.
The masterbatch of the present invention is suitable for use in cross-linking
a
cross-linkable elastomer. Examples of preferable elastomers to cross-link are
EPM, EPDM, ethylene-vinyl acetate copolymer, natural rubber, polybutadiene,
polyisoprene, polybutylene, polyisobutylene, polyacrylic acid ester, styrene-
butadiene copolymer, acrylonitrile-butadiene copolymer, hydrogenated
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acrylonitrile-butadiene copolymer, acrylonitrile-butadiene-styrene terpolymer,
fluorinated rubber, silicone rubber, urethane rubber, polyethylene, ethylene-a-
olefine copolymer, and chlorinated polyethylene.
The high-concentration cross-linking masterbatch of the present invention is
typically used in amount of by 0.2-20% by weight, preferably 1-10% by weight,
relative to the weight of the elastomer to be cross-linked.
Cross-linking of the elastomer may be carried out using any conventional
process. In such processes the elastomer to be cross-linked typically is first
homogeneously mixed with an inactive filler such as talc and calcium
carbonate, a pigment such as carbon black, a processing oil for better
processing, etc., and then kneaded with the required amount of the high-
concentration cross-linking masterbatch of the present invention. In the
subsequent cross-linking step the mixture is typically heated to 140-
200°C for
5-30 min in a mould. Depending on the type of elastomer and the types of
ingredients used, the cross-linking conditions may vary.
EXAMPLES
Example 1
Kayacumyl D (dicumyl peroxide made by Kayaku Akzo, mp (melting point)
38°C, purity 99%) was mixed homogeneously with Nipsil NS-P (specific
surface
area 170 m2/g), and then kneaded homogeneously with Esprene (EPDM made
by Sumitomo Kagaku, Mooney viscosity (ML 1+4 120°C) 80, propylene
content
45%) on an open roll mill using the amounts shown in Table 1. Subsequently,
the mixed product was cooled and pelletized in a conventional manner, to
obtain a granular high-concentration cross-linking masterbatch according to
the
present invention.
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Example 2
Perkadox 14 (m,p-bis(tert-butylperoxyisopropyl) benzene made by Kayaku
Akzo, mp (melting point) 43°C, purity 99%) was mixed homogeneously
with
Sipernat 50S (specific surface area 450 m2/g) and conventional light calcium
5 carbonate, and then kneaded homogeneously with Keltan 312 (EPDM made by
Idemitsu DSM, Mooney viscosity(ML 1+4 100°C) 52, propylene content
50%)
using an open roll mill and the compounding ratios shown in Table 1. The
product was cooled to ambient temperature and cut up into 50X50 cm square
sheets (masterbatch) according to the present invention.
Example 3
Kayacumyl D was mixed homogeneously with Aerosil 200 (specific surface area
200 m2/g), surface-treated calcium carbonate (Hakuenka CCR made by
Shiroishi Kogyo), and regular polybutene as a processing oil, and then kneaded
homogeneously with Mitsui EPT0045 (EPM made by Mitsui Kagaku, Mooney
viscosity (ML 1+4 100°C) 38, propylene content 49%) on an open roll
mill using
the compounding ratios shown in Table 1. The product was cooled to ambient
temperature and cut up into 50X50 cm square sheets (masterbatch) according
to the present invention.
Example 4
Perkadox 14 was mixed homogeneously with Finesil X80 (specific surface area
250 m2/g) and regular talc and then kneaded homogeneously with JSR-EP11
(EPM made by Nihon Gosei Gum, Mooney viscosity (ML 1+4 100°C) 40,
propylene content 49%) using an open roll mill and the compounding ratios
shown in Table 1. The product was cooled and pelletized to obtain a granular
high-concentration cross-linking masterbatch of the present invention.
The cross-linking masterbatches of the present invention obtained in Examples
1-4 were tested for their storage stability. Their compounding ratios and
results
are shown in Table 1 and Table 2. In the tables, hardness is a value measured
in the conventional way using a Rubber Tester type C, the compounding ratio is
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shown as % by weight, and the abbreviations have the following meaning:
PO: organic peroxide
KYKD: Kayacumyl D
PKD: Perkadox 14
Mitsui0045: Mitsui EPT0045
EP11: JSR-EP11
ES532: Esprene 532
KT312: Keltan 312
NipNSP: Nipsil NS-P
Sipe50S: Sipernate 50S
Fi50S: Finesi150S
Aero200: Aerosi1200
LCC: Light calcium carbonate
CCR: Hakuenka CCR
PO cone(%):PO concentration(%) as analyzed in the product
Table 1 Compounding Ratio
Exam 1e Exam 1e Exam 1e Exam 1e
1 2 3 4
PO KYKD PKD14 KYKD PKD14
Ratio % 45.1 50.3 55.2 65.0
EMP Mitsui EP11
EMDP ES532 KT312 0045
Ratio(%) 30.0 25.0 20.0
25.0
Wet-treated NipNSP Sipe50S Fi50S
silica /
Dry- ero200
treated silica4.9 8.0 15.0 4.0
Ratio %
Filler LCC CCR Talc
Ratio % 6.7 3.0 1.0
Additive Polybuten
a
Ratio % 1.8
Sha a Granular Sheet Sheet Granular
PO conc. 44.5 49.8 54.6 64.3
%
Hardness 60 59 55 59
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i apie c a staoiiit u~c;/atter
atora test 4 4 weeKs
Exam 1e 1 Exam 1e Exam 1e Exam 1e
2 3 4
Remaining 98.8 98.5 98.1 98.7
PO
A earance No than a No than No than No than
a a a
Hardness 60 57 54 60
Example 5
Trigonox 29 (made by Kayaku Akzo, 1,1-di-tert-butylperoxy-3,3,5-trimethyl
cyclohexane, liquid at ambient temperature, purity 95%) was mixed
homogeneously with Silicia 250N (pore volume 1.80 ml/g), Hakuenka CCR, and
conventional polybutene, and then kneaded homogeneously with Esprene 532
using an open roll mill and the compounding ratios shown in Table 3. The
product was cooled to ambient temperature and cut up into 50X50 cm square
sheets, to give a high-concentration cross-linking masterbatch of the present
invention.
Example 6
Trigonox 29 was mixed homogeneously with Mizukasolb C-1 (pore volume 1.70
ml/g) and then kneaded homogeneously with Keltan 312 on an open roll mill,
using the compounding ratios shown in Table 3. The product was cooled to
ambient temperature and cut up into 50X50 cm square sheets, to give a high-
concentration cross-linking masterbatch of the present invention.
Example 7
Kayahexa AD (made by Kayaku Akzo, 2,5-dimethyl-2,5-di (tert-butylperoxy)
hexane, liquid at ambient temperature, purity 90%) was mixed homogeneously
with Mizukasil P-7 (pore volume 1.57 ml/g) and regular talc, and then kneaded
homogeneously with Mitsui EPT 0045 using an open roll mill and the
compounding ratios shown in Table 3. The product was cooled to ambient
temperature and pelletized, to give a granular high-concentration cross-
linking
masterbatch according to the present invention.
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Example 8
Trigonox 17 (made by Kayaku Akzo, 4,4-di-tert-butylperoxyvaleric acid n-butyl
ester, liquid at ambient temperature, purity 90%) was mixed homogeneously
with Silicia 350 (pore volume 1.60 ml/g) and then kneaded homogeneously with
JSR-EP11 on an open roll mill using the compounding ratios shown in Table 3.
The product was cooled to ambient temperature and pelletized, to give a
granular high-concentration cross-linking masterbatch according to the present
invention.
The cross-linking masterbatches of the present invention obtained in Examples
5-8 were tested for their storage stability, see Tables 3 and 4. In the
tables, the
compounding ratio is shown as percentage by weight, and the abbreviations
have the following meaning:
TRN29: Trigonox 29
KYHAD: Kayahexa AD
Si: Silicia
Miso: Mizukasolb
Misi: Mizukasil
Porous Si: Porous silica
The other abbreviations have the same meaning as in Table 1.
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Table 3 Compounding Ratio
Exam 1e Exam 1e -Example Exam 1e
5 6 7 8
PO TRN29 TRN29 KYHAD TRN17
Ratio % 44.4 50.0 55.0 65.0
EPM Mitsui0045 EP11
EPDM ES532 Kt312
Ratio % 30.0 25.0 20.0 20.0
Porous Si Si250N MisoC-1 MisiP-707 Si350
Ratio % 25.6 20.0 19.0 14.0
Filler LCC CCR Talc
Ratio % 5.0 4.0 1.0
Additive Polybutene
Ratio % 2.0
Sha a Granular Sheet Sheet Granular
PO conc. 42.0 47.7 51.6 59.2
%
Hardness 35 37 33 36
Table 4 Storage stability test (40°C/after 4weeks)
Exam 1e Exam 1e Exam 1e Exam 1e
5 6 7 8
Remainin PO % 98.7 98.9 98.3 _98.6
A earance No chan No chan No chan No chan
a a a a
Hardness 36 37 33 38
Table 2 and Table 4 reveal that the high-concentration cross-linking
masterbatch of the present invention loses little organic peroxide and shows
almost no change in appearance and hardness over its storage, so that it has
excellent storage stability.
Examples 9-12
The masterbatches produced in Examples 1-4 were evaluated with respect to
their respective cross-linking performances. The prescribed ingredients were
mixed at the ratios shown in Table 5. A Banbury mixer was used to obtain the
EPDM compound into which each the masterbatches of Examples 1-4 was
dispersed at the given ratio using a two-roll mill.
The amount of masterbatch dispersed into the EPDM compound was chosen
such that 0.185 g of active oxygen (from the organic peroxide) was added per
100 g of EPDM.
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Table 5 shows the time required to disperse each of the corresponding
masterbatches into the EPDM compound.
5 Each of the elastomer compositions was cross-linked at 180°C for 15
min.
The cross-linking property of each the treated elastomer compositions was
measured by a culastometer (type JSR3). Tao and T9o stand for the time to
reach 10% and 90% of maximum torque, respectively.
The cross-linked elastomer was subject to a tensile strength test and a
tearing
strength test based on JISK-6301. Tb and Eb mean tension and elongation at
break, respectively. Hs and TR mean hardness and resistant strength against
tearing of a cross-linked elastomer, respectively.
Table 5 shows compounding ratios of ingredients and test results. In the
table,
JSR-EP86 is the trade name for EPDM made by Nihon Gosei Gum KK. Asahi
carbon #70 and Sunpar 2280 made by Nihon Sun Sekiyu KK were used as
HAF carbon black and naphthenic processing oil, respectively. A phenolic
ageing protector was used. The abbreviations have the following meaning:
TMPT: trimethylolpropane trimethacrylate
JSREP86: JSR-EP86
HAF-C: HAF carbon black
NP oil: naphthenic processing oil
A: The masterbatch produced in Example 1
B: The masterbatch produced in Example 2
C: The masterbatch produced in Example 3
D: The masterbatch produced in Example 4
"A 7.2" in the masterbatch row of the table means that 7.2 parts of the
masterbatch produced in Example 1 were used. The other masterbatch
abbreviations have corresponding meanings.
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Table 5 Elastomer compositions (parts by weight) and results
Exam 1e Exam 1e Exam 1e Exam 1e
9 10 11 12
JSREP86 100 100 100 100
HAF-C 50 50 50 50
NP oil 10 10 10 10
A ein 2 2 2 2
rotector
TMPT 2 2 2 2
Stearic 1 1 1 1
acid
Zinc 5 5 5 5
oxide
Masterbatch A 7.2 B 4.0 C 5.9 D 3.1
Dis 3.5 3.1 2.2 2.5
erse
time
min
Cross- T,o min 1.3 1.0 1.3 1.1
linkingT9o min 8.8 8.2 8.9 8.3
propertyMax torque 34 36 35 35
k f/cm
TensileTB k f/cm 180 174 177 175
strengthEB % 450 410 430 420
test Hs JIS-A 71 71 71 71
TearingTR (kgf/cm)43 41 43 41
test
Examples 13-16
The cross-linking properties of the masterbatches produced in Examples 13-16
were evaluated in the same way as was done in Examples 5-8, except that the
cross-linking conditions were 150°C for 15 min in Examples 13 and 14,
180°C
for 15 min in Example 15, and 160°C for 15 min in Example 16.
The results are compiled in Table 6.
The following abbreviations were used:
E: The masterbatch produced in Example 5
F: The masterbatch produced in Example 6
G: The masterbatch produced in Example 7
H: The masterbatch produced in Example 8
CA 02378297 2002-O1-04
WO 01/04200 PCT/EP00/06246
17
Table 6 Elastomer compositions (parts by weight) and results
Exam 1e Exam 1e14 Exam 1e15 Exam 1e
13 16
JSREP86 100 100 100 100
HAF-C 50 50 50 50
NP oil 10 10 10 10
A ein 2 2 2 2
rotector
TMPT 2 2 2 2
Stearic 1 1 1 1
acid
Zinc 5 5 5 5
oxide
Masterbatch E 8.2 F 7.3 G 6.3 H 6.2
Dis erse 2.8 1.5 1.0 1.2
time
min
Cross- T,o min 0.8 0.8 1.4 1.1
~
linking T9o min 5.1 5.2 8.9 5.5
propertyMax torque13 13 30 13
k f/cm
Tensile TB k f/cm 182 183 177 180
strengthEB % 350 340 330 340
test Hs JIS-A 63 63 68 63
Tearing TR (kgf/cm)42 42 40 41
test
Table 5 and Table 6 show that the cross-linking masterbatches of the present
invention can be readily dispersed into an elastomer and that their use
results
in cross-linked products having excellent properties such as mechanical
strength, i.e. tensile strength and resistance against tearing.
Clearly, the present invention provides effective, highly concentrated organic
peroxide masterbatches having excellent storage stability.
