U.S. patent application number 12/281348 was filed with the patent office on 2008-12-25 for elastomer composition, method for producing same, and pneumatic tire using same.
This patent application is currently assigned to The Yokohama Rubber Co., Ltd.. Invention is credited to Yuichi Hara.
Application Number | 20080314493 12/281348 |
Document ID | / |
Family ID | 38459242 |
Filed Date | 2008-12-25 |
United States Patent
Application |
20080314493 |
Kind Code |
A1 |
Hara; Yuichi |
December 25, 2008 |
Elastomer Composition, Method for Producing Same, and Pneumatic
Tire Using Same
Abstract
An elastomer composition, having an excellent flexibility and
low temperature durability, a method for producing the same and a
pneumatic tire using the same are provided. An elastomer
composition (C) comprising a matrix of a thermoplastic resin (A),
in which a dispersed phase of an elastomer component (B) is finely
dispersed to form an island-in-sea structure, wherein volume ratios
of the thermoplastic resin (A) and the elastomer component (B)
satisfy the following formula (I): .PHI.d/.PHI.m>.eta.d/.eta.m
(I) wherein .PHI.d and .eta.d, respectively, indicate a volume
ratio and a melt viscosity of the elastomer component (B), and
.PHI.m and .eta.m, respectively, indicate a volume ratio and a melt
viscosity of the thermoplastic resin (A)), a method for producing
the same and a pneumatic tire using the same.
Inventors: |
Hara; Yuichi; (Kanagawa,
JP) |
Correspondence
Address: |
CONNOLLY BOVE LODGE & HUTZ LLP
1875 EYE STREET, N.W., SUITE 1100
WASHINGTON
DC
20006
US
|
Assignee: |
The Yokohama Rubber Co.,
Ltd.
Tokyo
JP
|
Family ID: |
38459242 |
Appl. No.: |
12/281348 |
Filed: |
March 2, 2007 |
PCT Filed: |
March 2, 2007 |
PCT NO: |
PCT/JP2007/054618 |
371 Date: |
September 2, 2008 |
Current U.S.
Class: |
152/510 ;
525/190 |
Current CPC
Class: |
C08L 77/06 20130101;
C08L 21/00 20130101; C08L 77/06 20130101; C08K 5/0016 20130101;
C08J 3/005 20130101; C08L 77/00 20130101; C08K 5/0025 20130101;
C08L 77/00 20130101; C08L 77/02 20130101; C08L 21/00 20130101; C08L
77/06 20130101; C08L 21/00 20130101; C08L 23/283 20130101; C08L
77/02 20130101; C08L 77/02 20130101; C08L 9/06 20130101; C08L 9/00
20130101; B60C 1/0008 20130101; C08L 2205/22 20130101; C08K 5/09
20130101; C08L 77/00 20130101; C08K 3/22 20130101; C08L 23/22
20130101; C08L 77/00 20130101; C08L 2666/14 20130101; C08L 2666/08
20130101; C08L 2666/08 20130101; C08L 2666/04 20130101; C08L
2666/04 20130101; C08L 2666/04 20130101; C08L 2666/08 20130101 |
Class at
Publication: |
152/510 ;
525/190 |
International
Class: |
B60C 5/14 20060101
B60C005/14; C08L 19/00 20060101 C08L019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 3, 2006 |
JP |
2006-058273 |
Claims
1. An elastomer composition (C) characterized by comprising a
matrix of a thermoplastic resin (A) in which a dispersed phase of
an elastomer component (B) is finely dispersed to form an
island-in-sea structure, wherein volume ratios of the thermoplastic
resin (A) and the elastomer component (B) satisfy the following
formula (I): .PHI.d/.PHI.m>.eta.d/.eta.m (I) where .PHI.d and
.eta.d, respectively, indicate a volume ratio and a melt viscosity
of the elastomer component (B) and .PHI.m and .eta.m, respectively,
indicate a volume ratio and a melt viscosity of the thermoplastic
resin (A).
2. An elastomer composition (C) as claimed in claim 1, wherein the
volume ratio of elastomer component (B) is 55 to 95%.
3. An elastomer composition (C) as claimed in claim 1, wherein the
thermoplastic resin (A) is at least one thermoplastic resin
selected from the group consisting of Nylon 6, Nylon 6/66
copolymer, Nylon 11, Nylon 12, a Nylon 6/10 copolymer and a Nylon
6/12 copolymer.
4. An elastomer composition (C) as claimed in claim 1, wherein the
elastomer component (B) is at least one elastomer selected from the
group consisting of a bromide of an isoprene-paramethyl styrene
copolymer, a maleic anhydride-modified ethylene-.alpha.-olefin
copolymer, butyl rubber, halogenated butyl rubber and polyisoprene
rubber.
5. A method for producing an elastomer composition (C) according to
claim 1 comprising the steps of: mixing and shaping a thermoplastic
resin (A), an elastomer component (B) and a plasticizer (D) in a
ratio satisfying the following formulae (II) and (III):
.PHI.d/(.PHI.m+.PHI.1).times.(.eta.ml/.eta.d)<1 (II)
.eta.ml/.eta.d=0.8-1.2 (III) wherein .PHI.d and .eta.d,
respectively, indicate a volume ratio and a viscosity of the
elastomer component (B), .PHI.m indicates a volume ratio of the
thermoplastic resin (A), .PHI.1 indicates a volume ratio of the
plasticizer (D) and .eta.ml indicates a melt viscosity of a mixture
of the thermoplastic resin (A) and the plasticizer (D); and, then,
removing the plasticizer (D) by evaporation, extraction or
migration.
6. A method for producing an elastomer composition (C) according to
claim 5, wherein the plasticizer (D) is alkylbenzene
sulfonamide.
7. A pneumatic tire using an elastomer composition (C) according to
claim 1 as an inner liner.
8. An elastomer composition (C) as claimed in claim 2, wherein the
thermoplastic resin (A) is at least one thermoplastic resin
selected from the group consisting of Nylon 6, Nylon 6/66
copolymer, Nylon 11, Nylon 12, a Nylon 6/10 copolymer and a Nylon
6/12 copolymer.
9. An elastomer composition (C) as claimed in claim 2, wherein the
elastomer component (B) is at least one elastomer selected from the
group consisting of a bromide of an isoprene-paramethyl styrene
copolymer, a maleic anhydride-modified ethylene-.alpha.-olefin
copolymer, butyl rubber, halogenated butyl rubber and polyisoprene
rubber.
10. An elastomer composition (C) as claimed in claim 3, wherein the
elastomer component (B) is at least one elastomer selected from the
group consisting of a bromide of an isoprene-paramethyl styrene
copolymer, a maleic anhydride-modified ethylene-.alpha.-olefin
copolymer, butyl rubber, halogenated butyl rubber and polyisoprene
rubber.
11. A method for producing an elastomer composition (C) according
to claim 2 comprising the steps of: mixing and shaping a
thermoplastic resin (A), an elastomer component (B) and a
plasticizer (D) in a ratio satisfying the following formulae (II)
and (III): .PHI.d/(.PHI.m+.PHI.1).times.(.eta.ml/.eta.d)<1 (II)
.eta.ml/.eta.d=0.8-1.2 (III) wherein .PHI.d and .eta.d,
respectively, indicate a volume ratio and a viscosity of the
elastomer component (B), .PHI.m indicates a volume ratio of the
thermoplastic resin (A), .PHI.1 indicates a volume ratio of the
plasticizer (D) and .eta.ml indicates a melt viscosity of a mixture
of the thermoplastic resin (A) and the plasticizer (D); and, then,
removing the plasticizer (D) by evaporation, extraction or
migration.
12. A method for producing an elastomer composition (C) according
to claim 3 comprising the steps of: mixing and shaping a
thermoplastic resin (A), an elastomer component (B) and a
plasticizer (D) in a ratio satisfying the following formulae (II)
and (III): .PHI.d/(.PHI.m+.PHI.1).times.(.eta.ml/.eta.d)<1 (II)
.eta.ml/.eta.d=0.8-1.2 (III) wherein .PHI.d and .eta.d,
respectively, indicate a volume ratio and a viscosity of the
elastomer component (B), .PHI.m indicates a volume ratio of the
thermoplastic resin (A), .PHI.1 indicates a volume ratio of the
plasticizer (D) and .eta.ml indicates a melt viscosity of a mixture
of the thermoplastic resin (A) and the plasticizer (D); and, then,
removing the plasticizer (D) by evaporation, extraction or
migration.
13. A method for producing an elastomer composition (C) according
to claim 4 comprising the steps of: mixing and shaping a
thermoplastic resin (A), an elastomer component (B) and a
plasticizer (D) in a ratio satisfying the following formulae (II)
and (III): .PHI.d/(.PHI.m+.PHI.1).times.(.eta.ml/.eta.d)<1 (II)
.eta.ml/.eta.d=0.8-1.2 (III) wherein .PHI.d and .eta.d,
respectively, indicate a volume ratio and a viscosity of the
elastomer component (B), .PHI.m indicates a volume ratio of the
thermoplastic resin (A), .PHI.1 indicates a volume ratio of the
plasticizer (D) and .eta.ml indicates a melt viscosity of a mixture
of the thermoplastic resin (A) and the plasticizer (D); and, then,
removing the plasticizer (D) by evaporation, extraction or
migration.
14. A pneumatic tire using an elastomer composition (C) according
to claim 2 as an inner liner.
15. A pneumatic tire using an elastomer composition (C) according
to claim 3 as an inner liner.
16. A pneumatic tire using an elastomer composition (C) according
to claim 4 as an inner liner.
17. A method for producing an elastomer composition (C) according
to claim 11, wherein the plasticizer (D) is alkylbenzene
sulfonamide.
18. A method for producing an elastomer composition (C) according
to claim 12, wherein the plasticizer (D) is alkylbenzene
sulfonamide.
19. A method for producing an elastomer composition (C) according
to claim 13, wherein the plasticizer (D) is alkylbenzene
sulfonamide.
20. An elastomer composition (C) as claimed in claim 8, wherein the
elastomer component (B) is at least one elastomer selected from the
group consisting of a bromide of an isoprene-paramethyl styrene
copolymer, a maleic anhydride-modified ethylene-.alpha.-olefin
copolymer, butyl rubber, halogenated butyl rubber and polyisoprene
rubber.
Description
TECHNICAL FIELD
[0001] The present invention relates to an elastomer composition, a
method for producing the same and a pneumatic tire using the same.
More specifically, it relates to an elastomer composition having an
excellent flexibility and low temperature durability, while
maintaining the characteristics of the resin, a method for
producing the same and a pneumatic tire using the same.
BACKGROUND ART
[0002] A thermoplastic elastomer composition comprising a matrix
(i.e., a continuous phase) of a thermoplastic resin, in which a
rubber is finely dispersed (i.e., a dispersed phase) is known. It
is known in the art that an island-in-sea structure, in which the
rubber is surrounded with the resin, is formed under the conditions
satisfying the formula (IV) explained later (e.g., see Japanese
Patent Publication (A) No. 2000-159936). To obtain a rubbery
elastomer from a composition obtained in a state where a
thermoplastic resin forms a matrix, it is necessary to increase the
amount of rubber as much as possible. However, when a large amount
of rubber is compounded, the thermoplastic resin serving as the
continuous phase and the elastomer component serving as the
dispersed phase invert in phase, and, therefore, the thermoplastic
elastomer composition thus prepared does not exhibit the fluidity
of the thermoplastic resin and the shaping becomes impossible.
Therefore, there have been limits to the amount of rubber which
could be compounded.
DISCLOSURE OF THE INVENTION
[0003] Accordingly, an object of the present invention is to
provide an elastomer composition (C) having a flexible and low
temperature durability comprising a matrix of a relatively small
amount of a thermoplastic resin (A), in which a relatively large
amount of an elastomer component (B) is finely dispersed, a method
for producing the same and a pneumatic tire using the same.
[0004] In accordance with the present invention, there are provided
an elastomer composition (C) comprising a matrix of a thermoplastic
resin (A), in which a dispersed phase of an elastomer component (B)
is finely dispersed to form an island-in-sea structure, wherein
volume ratios of the thermoplastic resin (A) and the elastomer
component (B) satisfy the following formula (I):
.PHI.d/.PHI.m>.eta.d/.eta.m (I)
wherein .PHI.d and .eta.d, respectively, indicate a volume ratio
and a melt viscosity of the elastomer component (B), and .PHI.m and
.eta.m, respectively, indicate a volume ratio and a melt viscosity
of the thermoplastic resin (A)) and a pneumatic tire using the
same.
[0005] In accordance with the present invention, there is further
provided a method for producing the above-mentioned elastomer
composition (C) comprising the steps of: mixing and shaping a
thermoplastic resin (A), an elastomer component (B) and a
plasticizer (D) in a ratio satisfying the following formulae (II)
and (III):
.PHI.d/(.PHI.m+.PHI.1).times.(.eta.ml/.eta.d)<1 (II)
.eta.ml/.eta.d=0.8-1.2 (III)
wherein .PHI.d and .eta.d, respectively, indicate a volume ratio
and a viscosity of the elastomer component (B), .PHI.m indicates a
volume ratio of the thermoplastic resin (A), .PHI.l indicates a
volume ratio of the plasticizer (D), and .eta.ml indicates a melt
viscosity of a mixture of the thermoplastic resin (A) and the
plasticizer (D); and, then,
[0006] removing the plasticizer (D) by evaporation, extraction or
migration.
[0007] According to the present invention, it is possible to obtain
a flexible elastic body, while maintaining the properties of the
thermoplastic resin, for example, it is possible to prepare an
inner liner having a combination of heat resistance, low gas
permeability, chemical resistance and high dynamic durability when
using Nylon, as the thermoplastic resin, and using a butyl-based
rubber as the elastomer. Due to similar characteristics, it is also
possible to use the elastic body for hose inner liners, packing,
etc.
BEST MODE FOR CARRYING OUT THE INVENTION
[0008] The inventors engaged in research to solve the above
problems and, as a result, found that, by mixing and shaping a
thermoplastic resin (A), an elastomer component (B) and a
plasticizer (D) in a composition satisfying the above formula (II)
to obtain an island-in-sea structure, where the resin (A) forms the
sea and the elastomer (B) forms the islands. After the final shape
is formed, a part of the composition is removed, it becomes
possible to obtain an island-in-sea structure having a highly
increased ratio of the elastomer more than the limit ordinarily
obtainable, whereby a flexible elastic body due to the high amount
of elastomer, while maintaining the characteristics of the matrix
thermoplastic resin (A).
[0009] To produce a conventionally known thermoplastic elastomer
composition comprised of a matrix of a thermoplastic resin
component, in which an elastomer component is dispersed (see
Japanese Patent Publication (A) No. 9-100413, Japanese Patent
Publication (A) No. 2000-159936, etc.), the following conditions
are necessary. That is, when a volume ratio of the thermoplastic
resin component forming the matrix (i.e., continuous phase) is
.PHI.m, a viscosity at the time of melt mixing is .eta.m, a volume
ratio of the elastomer component forming the dispersed phase is
.PHI.d, a viscosity under the same conditions is .eta.d, it is
necessary to mix the two components so that the value of
.alpha.=(.PHI.d/.PHI.m).times.(.eta.m/.eta.d)
becomes smaller than 1. That is,
(.PHI.d/.PHI.m).times.(.eta.m/.eta.d)<1 (IV)
[0010] This is because, when the microstructure of the
thermoplastic elastomer composition thus produced has the .alpha.
value of smaller than 1, the thermoplastic resin component becomes
the continuous phase (i.e., matrix) and the elastomer component
becomes the dispersed phase (i.e., domain), and, therefore, molding
becomes possible by the molding method of thermoplastic resins, but
when a is 1 or more, the continuous phase and the dispersed phase
are inverted, and, therefore, the thermoplastic elastomer
composition thus prepared does not exhibit the fluidity of a
thermoplastic resin and, therefore, molding by a molding machine
for resin becomes possible. Further, when a larger amount of
elastomer, if more than a certain amount is compounded, the .alpha.
tends to become larger than 1 and the continuous phase and the
dispersed phase become inverted. There were inherent limits in the
conventional known production methods for further increasing the
elastomer ratio, while maintaining the relationship between the
continuous phase comprised of the thermoplastic resin and the
dispersed phase comprised of the elastomer.
[0011] The present invention provides an elastomer composition,
where it is maintained in such a state that a thermoplastic resin
component (A) is a continuous phase (i.e., matrix) and an elastomer
component (B) is a dispersed phase (i.e., domain), the volume ratio
of the elastomer component (B) in the resin is increased to an
extent which could not be realized in a conventional production
method and a method for producing the same.
[0012] That is, while the elastomer composition (C) satisfies
(.PHI.d/.PHI.m).times.(.eta.m/.eta.d)>1 (I)
a state of a continuous phase (i.e., matrix) of a thermoplastic
resin component (A), in which an elastomer component (B) is present
as a dispersed phase (i.e., domain), is formed.
[0013] Furthermore, the method for producing the elastomer
composition (C) is as follows:
[0014] The plasticizer (D) is compounded into the thermoplastic
resin component (A) as a pseudo resin component, together with the
elastomer component (B), so as to satisfy the following
conditions:
(.PHI.d/(.PHI.m+.PHI.l)).times.(.eta.ml/.eta.d)<1 (II)
.eta.ml/.eta.d=0.8-1.2 (III)
wherein .PHI.d and .PHI.d, respectively, indicate a volume ratio
and a viscosity of the elastomer component (B), .PHI.m indicates a
volume ratio of the thermoplastic resin (A), .PHI.l indicates a
volume ratio of the plasticizer (D), and .eta.ml indicates a melt
viscosity of a mixture of the thermoplastic resin (A) and the
plasticizer (D)).
[0015] Due to the above compounding, a thermoplastic elastomer
composition (E) comprising a thermoplastic resin component (A)
including a plasticizer (D) forming a continuous phase (i.e.,
matrix) and an elastomer component (B) forming a dispersed phase
(i.e., domain) is first produced. Here, the formula (III) shows
that, when the viscosity ratio .eta.ml/.eta.d is made within a
range of 0.8 to 1.2, it is possible to make the dispersed particles
of the elastomer smaller. It is known in the art that, when the
dispersed particles is made smaller, the durability is improved
(See Japanese Patent Publication (A) No. 2000-159936).
[0016] Here, .PHI.1/(.PHI.m+.PHI.1) is 0.05 to 0.6, more preferably
0.1 to 0.3.
[0017] Although the composition (E) thus produced is still of
thermoplasticity, the elastomer composition (C) is produced by
evaporating, extracting or migrating the plasticizer (D) from the
composition (E). Note that this elastomer composition (C) loses its
thermoplasticity.
[0018] As the thermoplastic resin (A) usable for preparation of the
elastomer composition (C) of the present invention, one or more
types of thermoplastic resins may be used. As the resin component,
polyamide-based resins (e.g., Nylon 6 (N6), Nylon 66 (N66), Nylon
46 (N46), Nylon 11 (N11), Nylon 12 (N12), Nylon 610 (N610), Nylon
612 (N612), Nylon 6/66 copolymer (N6/66), Nylon Jun. 66, 19610
copolymer (N6/66/610), Nylon MXD6 (MXD6), Nylon 6T, Nylon 6/6T
copolymer, Nylon 66/PP copolymer, and Nylon 66/PPS copolymer), a
polyester-based resin (e.g., aromatic polyesters such as
polybutylene terephthalate (PBT), polyethylene terephthalate (PET),
polyethylene isophthalate (PEI), PET/PEI copolymer, polyarylate
(PAR), polybutylene naphthalate (PBN), liquid crystal polyester,
polyoxyalkylene diimidic acid/polybutylene terephthalate
copolymer), polynitrile-based resins (e.g., polyacrylonitrile
(PAN), polymethacrylonitrile, acrylonitrile/styrene copolymer (AS),
methacrylonitrile/styrene copolymer,
methacrylonitrile/styrene/butadiene copolymer), a
polymethacrylate-based resins (e.g., polymethyl methacrylate (PMMA)
and polyethyl methacrylate), polyvinyl-based resins (e.g., vinyl
acetate (EVA), polyvinyl alcohol (PVA), vinyl alcohol/ethylene
copolymer (EVOH), polyvinylidene chloride (PVDC), polyvinyl
chloride (PVC), vinyl chloride/vinylidene chloride copolymer, and
vinylidene chloride/methyl acrylate copolymer), cellulose-based
resins (e.g., cellulose acetate and cellulose acetobutyrate),
fluorine-based resins (e.g., polyvinylidene fluoride (PVDF),
polyvinyl fluoride (PVF), polychlorofluoroethylene (PCTFE) and
tetrafluoroethylene/ethylene copolymer (ETFE)), imide-based resins
(e.g., aromatic polyimide (PI)), etc. may be mentioned. Among
these, linear polyamide resins such as Nylon are preferably used
from the viewpoint of obtaining a balance of the durability and the
gas barrier property.
[0019] Further, to the thermoplastic resin (A) forming the matrix
of the elastomer composition, fillers, reinforcing agents,
processing aids, stabilizers, antioxidants, etc. generally used for
improving the workability, dispersability, heat resistance,
antioxidation ability, etc. may be compounded, if necessary.
[0020] The elastomer component (B) usable for the preparation of
the elastomer composition according to the present invention may be
an elastomer composition comprising an elastomer component, in
which the usual rubber compounding agents including the
vulcanization compounding components have been compounded.
Alternatively, it may be an elastomer composition comprising the
elastomer component, in which the usual rubber compounding agents
other than the vulcanization compounding components have been
compounded. As such an elastomer component, natural rubber,
synthetic polyisoprene rubber (IR), epoxylated natural rubber,
styrene-butadiene rubber (SBR), polybutadiene rubber (BR),
nitrile-butadiene rubber (NBR), hydrogenated NBR, hydrogenated SBR,
or other such diene-based rubbers and their hydrogenated compounds;
ethylene propylene rubber (EPDM, EPM), maleic acid-modified
ethylene-.alpha.-olefin copolymer (M-PO), butyl rubber (IIR),
isobutylene and aromatic vinyl or diene-based monomer copolymer,
acryl rubber (ACM), ionomer, or other such olefin-based rubbers;
Br-IIR, Cl-IIR, a bromide of isobutylene paramethylstyrene
copolymer (Br-IPMS), chloroprene rubber (CR), hydrin rubber (CHC,
CHR), chlorosulfonated polyethylene (CSM), chlorinated polyethylene
(CM), maleic acid-modified chlorinated polyethylene (M-CM), or
other such halogen-containing rubbers; methylvinyl silicone rubber,
dimethyl silicone rubber, methylphenylvinyl silicone rubber, or
other such silicone rubbers; polysulfide rubber or other such
sulfur-containing rubbers; vinylidene fluoride-based rubbers,
fluorine-containing vinyl ether-based rubber,
tetrafluoroethylene-propylene-based rubber, fluorine-containing
silicone-based rubber, fluorine-containing phosphagen-based rubber
or other such fluororubbers; a styrene-based elastomer,
olefin-based elastomer, polyester-based elastomer, urethane-based
elastomer, polyamide-based elastomer, or other such thermoplastic
elastomer, etc. may be mentioned.
[0021] The elastomer component (B) forming the dispersed phase of
the elastomer composition (C) according to the present invention
may also be dynamically vulcanized. The vulcanization agent,
vulcanization aid and vulcanization conditions (e.g., temperature
and time) etc. in the case of dynamic vulcanization may be
appropriately determined depending upon the composition of the
elastomer component (B) added and is not particularly limited. As
the vulcanization agent, general rubber vulcanization agents (e.g.,
cross-linking agents) may be used. Specifically, as sulfur-based
vulcanization agents, powdered sulfurs, precipitated sulfurs,
dispersible sulfurs, surface treated sulfurs, insoluble sulfurs,
dimorpholine disulfides, alkylphenol sulfides, etc. may be
mentioned. For example, about 0.5 to 4 parts by weight (parts by
weight per 100 parts by weight of elastomer component (or polymer))
or so may be used.
[0022] Further, as an organic peroxide system vulcanization agent,
benzoyl peroxide, t-butylhydroperoxide, 2,4-dichlorobenzoyl
peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane,
2,5-dimethylhexane-2,5-di(peroxylbenzoate), etc. may be mentioned.
For example, about 1 to 20 parts by weight may be used.
Furthermore, as the phenol resin-based vulcanization agent, a mixed
cross-linking system containing a bromide of an alkylphenol resin,
stannous chloride, chloroprene, or another halogen donor and an
alkylphenol resin etc. may be illustrated. For example, about 1 to
20 parts by weight may be used.
[0023] As other compounding components, zinc white (about 5 parts
by weight), magnesium oxide (about 4 parts by weight), litharge
(about 10 to 20 parts by weight), p-quinone dioxime,
p-dibenzoylquinine oxime, tetrachloro-p-benzoquinone,
poly-p-dinitrosobenzene (about 2 to 10 parts by weight), and
methylene dianiline (about 0.2 to 10 parts by weight) may be
illustrated.
[0024] Further, if necessary, a vulcanization accelerator may also
be added. As the vulcanization accelerator, an
aldehyde-ammonia-based, guanidine-based, thiazole-based,
sulfonamide-based, thiuram-based, dithio acid salt-based,
thiourea-based, or other general vulcanization accelerators may be
used in an amount of, for example, about 0.5 to 2 parts by weight.
Further, as the vulcanization acceleration aid, a general aid for
rubber may be used together. For example, stearic acid, oleic acid,
and their Zn salts (about 2 to 4 parts by weight) etc. may be
used.
[0025] Furthermore, the elastomer component (B) forming the
dispersed phase may have suitably compounded, in addition to the
above compounding agents, a softening agent, antioxidant,
processing aid, etc. generally compounded for improving the
dispersability, heat resistance, etc. if necessary.
[0026] As the plasticizer (D) usable in the method of production of
the present invention, alkylbenzene sulfonamide, diallyl phthalate,
dioctyl phthalate, dioctyl sebacate, dioctyl adipate, diisodecyl
phthalate, butylbenzyl phthalate, tricresyl phosphate, trimellitic
acid isononyl ester and other esters, methanol, ethanol,
2-propanol, and other alcohols, paraffin oil, naphthene oil,
aromatic oil, and other petroleum-based oils etc. may be used, but
from the viewpoints of a high boiling point and solubility with
resins, alkylbenzene sulfonamide is preferable.
[0027] In the present invention, the method for producing of an
elastomer composition (C) comprising a matrix resin (A), in which
an elastomer (B) is finely dispersed, may, for example, be as
follows: First, the elastomer and, if necessary, the compounding
agents are compounded, in advance, using a general kneader, Banbury
mixer, etc. until obtaining a homogeneous mixed state to prepare an
elastomer component (B). At this time, the elastomer component (B)
may have suitable amounts of carbon black, oil, or calcium
carbonate or another filler added thereto. Further, in the
necessary case, a vulcanization agent or cross-linking agent of the
elastomer, a vulcanization aid, vulcanization accelerator, etc. may
also be added. Next, the thermoplastic resin (A) forming the
matrix, the plasticizer (D), and the antioxidant or other
compounding agents compounded, if necessary, are charged into a
twin-screw kneader etc. and kneaded to prepare a thermoplastic
resin component (A) forming the matrix. The resin component (A)
thus prepared and the elastomer component (B) are charged into a
twin-screw extruder etc. for melt mixing. When using an elastomer
component (B) not containing any vulcanization compounding agents
for the elastomer component (B), the vulcanization compounding
agents may be added at the stage where sufficient mixing has been
performed and further mixed to dynamically cross-link the elastomer
component and obtain a thermoplastic elastomer composition (E).
[0028] Further, the various compounding agents may be added to the
thermoplastic resin component (A) or elastomer component (B) by
mixing, in advance, before the above twin-screw kneading, but may
also be added during the above twin-screw kneading. Furthermore,
the matrix resin, elastomer, various compounding agents and the
plasticizer may be kneaded by a twin-screw kneader etc. all at
once, but in that case, it is necessary to sufficiently knead the
matrix resin and the plasticizer, then add the elastomer. The
kneading of these elastomer component (B) and the matrix resin
component (A) and the melt kneading of the elastomer composition
should be conducted under the condition of a temperature, at which
a thermoplastic resin melts, or more. Further, the shear rate at
the time of kneading is preferably 500 to 7500 sec.sup.-1, while
the kneading time is preferably about 30 seconds to 10 minutes.
[0029] The thermoplastic elastomer composition (E) thus obtained is
then formed into a sheet, film or tube, using a T-type sheeting
die, a straight or crosshead structure tubing die, a cylindrical
die for inflation molding, etc. at the front end of a single-screw
extruder, then a part or all of the plasticizer (D) is removed by
evaporation with oven heating, by migration with laminating with
rubber, etc, followed by heat pressing, or by extraction using a
solvent such as methanol, etc. to thereby obtain the shaped
articles of the elastomer composition (C). For the utilization, as
a low permeability layer for a pneumatic tire, hose, etc., the
above thermoplastic elastomer composition (E) containing a
plasticizer is adhered in a laminated state with rubber to, for
example, the innermost layer of a tire or hose, the resultant
assembly is formed into the final shape, then heat pressing is used
to move the plasticizer (D) into the rubber so as to obtain a low
permeability layer formed from the elastomer composition (C). This
layer is composed of a resin as a matrix and rubber as a dispersed
phase, with an extremely large amount of rubber and, therefor,
becomes a flexible layer having a superior dynamic endurance like
rubber, while maintaining the characteristics of the resin, for
example, the low permeability, heat resistance and chemical
resistance.
EXAMPLES
[0030] Examples will now be used to further illustrate the present
invention, but the present invention is by no means limited in
scope by these Examples.
Examples 1 to 7 and Comparative Examples 1 to 7
Preparation of Samples
[0031] In each formulation shown in Table I, the elastomer and
cross-linking agent were mixed in an internal-type Banbury mixer
(made by Kobe Steel Corporation) at 100.degree. C. for 2 minutes to
prepare a compound, which was then pelletized by a rubber
pelletizer (made by Moriyama Manufacturing Co., Ltd.). Into the
resin pellets, a plasticizer for resin (i.e. butyl benzene
sulfonamide BM-4 made by Daihachi Chemical Industry Co., Ltd.) was
added to about 30% by weight, based upon the weight of the resin
(.PHI.1/(.PHI.m+.PHI.1)=0.26) and kneaded by a twin-screw type
kneader (made by Japan Steel Works), then the
plasticizer-containing resin thus obtained and the rubber pellets
were kneaded again by a twin-screw type kneader (made by Japan
Steel Works) to prepare pellets of a plasticizer-containing
elastomer composition, which was dynamically vulcanized. The
pellets thus prepared were formed into a sheet by a T-die molding
machine, the plasticizer was removed by extraction using methanol,
then the sheet was dried in a vacuum oven at 70.degree. C. for 12
hours to completely remove the methanol, whereby a sheet of the
elastomer composition was obtained.
Example 8
[0032] In the formulation shown in Table I, the elastomer and the
cross-linking agent were mixed in an internal-type Banbury mixer
(made by Kobe Steel Corporation) at 100.degree. C. for 2 minutes to
prepare an elastomer composition, which was then pelletized by a
rubber pelletizer (Moriyama Manufacturing Co., Ltd.). Into the
resin pellets, a plasticizer for resin (butyl benzene sulfonamide
BM-4 made by Daihachi Chemical Industry Co., Ltd.) was added to
about 30% by weight, based upon the weight of the resin and kneaded
by a twin-screw kneader (made by Japan Steel Works), then the
plasticizer-containing resin obtained and the elastomer pellets
were kneaded again by a twin-screw-type kneader (made by Japan
Steel Works) to prepare pellets of a plasticizer-containing
elastomer composition, which was (dynamically vulcanized. The
pellets prepared were formed into a sheet by a T-die molding
machine, which was then dried in a vacuum oven at 180.degree. C.
for 30 hours to evaporate off the plasticizer, whereby a sheet of
the elastomer composition was obtained.
Example 9
[0033] In the formulation shown in Table I, the elastomer and the
cross-linking agent were mixed in an internal-type Banbury mixer
(made by Kobe Steel Corporation) at 100.degree. C. for 2 minutes to
prepare an elastomer composition, which was the pelletized by a
rubber pelletizer (Moriyama Manufacturing Co., Ltd.). Into the
resin pellets, a plasticizer for resin (butyl benzene sulfonamide
BM-4 made by Daihachi Chemical Industry Co., Ltd.) was added to
about 30% by weight, based upon the weight of the resin and kneaded
by a twin-screw kneader (made by Japan Steel Works), then the
plasticizer-containing resin obtained and the elastomer pellets
were kneaded again by a twin-screw kneader (made by Japan Steel
Works) to prepare pellets of a plasticizer-containing elastomer
composition, which was dynamically vulcanized. The pellets prepared
were formed into a sheet by a T-die molding machine, which was then
sandwiched between 2 mm sheets of a rubber compound having the
following composition and then heat pressed at 180.degree. C. for
15 minutes to evaporate the plasticizer, whereby the plasticizer is
migrated to the rubber compound to thereby obtain a sheet of the
elastomer composition.
[0034] Composition of Rubber Compound
TABLE-US-00001 Parts by Component weight Manufacturer/Grade Natural
rubber 80 RSS#1 SBR1502 20 Nippon Zeon/Nipole 1502 FEF carbon black
50 Chubu Carbon/HTC100 Stearic acid 2 Kao/Lunac YA Zinc oxide 3
Seido Chemical Industrial/ Zinc White No. 3 Sulfur 3 Karuizawa
Refinery/ Powdered Sulfur Vulcanization 1 Ouchi Shinko Chemical
accelerator Industries noccelar NS-P Aromatic oil 2 Nippon
Petrolecim/Coumorex 300
[0035] The sheets obtained were determined for physical properties
by the following test methods. The results are shown in Table
I.
[0036] Test Methods for Evaluation of Physical Properties
Air permeability: According to JIS K 7126 "Test Method for Gas
Permeability of Plastic Film and Sheet (Method A)"
[0037] Test piece: A film sample prepared in each Example was
used
[0038] Test gas: air (N.sub.2:O.sub.2=8:2)
[0039] Test temperature: 30.degree. C.
[0040] To maintain the air pressure, 20.times.10.sup.-12
(cm.sup.3cm/cm.sup.2seccmHg) or less is good, while
15.times.10.sup.-12 (cm.sup.3cm/cm.sup.2seccmHg) or less is
preferable.
[0041] M50 (-20.degree. C.): Determined according to JIS K6251 at
-20.degree. C.
[0042] Dynamic fatigue (-20.degree. C.)
[0043] Constant strain test at -20.degree. C.: A JIS No. 3 dumbbell
was used to apply repeated strain of 40% by a constant strain
tester (made by Ueshima Seisakusho Works) at -20.degree. C. or
less. Samples with points of 70% breakage rates by a Weibull plot
exceeding 1 million cycles were judged as passing.
TABLE-US-00002 TABLE I Formulation (parts by weight) Ex. 1 Ex. 2
Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Ex. 9 Elastomer IPMS*.sup.1 100
100 100 90 80 70 -- 70 80 Mah-EPM*.sup.2 -- -- -- 10 -- -- 40 -- 10
Br-IIR*.sup.3 -- -- -- -- 20 -- -- -- -- IIR*.sup.4 -- -- -- -- --
30 -- -- 10 PIB*.sup.5 -- -- -- -- -- -- 60 30 -- Cross-linking
agent ZnO*.sup.6 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Stearic
acid*.sup.7 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Thermoplastic resin
Nylon 6,66*.sup.8 56 -- -- 60 67 67 60 56 42 Nylon 6*.sup.9 -- 53
-- -- -- -- -- -- -- Nylon 11*.sup.10 -- -- 53 -- -- -- -- -- 25
(Total) (157.5) (154.5) (154.5) (161.5) (168.5) (168.5) (161.5)
(157.5) (168.5) (.phi.d/(.phi.m + .phi.l)) .times. (.eta.ml/.eta.d)
(at kneading, 0.92 0.85 0.89 0.90 0.95 0.95 0.76 0.80 0.93 with
plasticizer) (.phi.d/.phi.m) .times. (.eta.m/.eta.d) (shaped 5.61
5.98 2.20 5.50 5.76 5.76 4.63 4.87 3.66 article, no plasticizer)
Air permeability .times. 10.sup.-12 8 6 12 8 9 8 7 7 9 (cm.sup.3
cm/cm.sup.2 sec cmHg) M50(-20.degree. C.) (MPa) 19 22 17 21 24 23
22 21 19 Dynamic fatigue Good Good Good Good Good Good Good Good
Good (-20.degree. C.) Comp. Comp. Comp. Comp. Comp. Comp. Comp.
Formulation (parts by weight) Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6
Ex. 7 Elastomer IPMS*.sup.1 100 100 100 90 80 70 70 Mah-EPM*.sup.2
-- -- -- 10 -- -- -- Br-IIR*.sup.3 -- -- -- -- 20 -- -- IIR*.sup.4
-- -- -- -- -- 30 -- PIB*.sup.5 -- -- -- -- -- -- 30 Cross-linking
agent ZnO*.sup.6 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Stearic acid*.sup.7
0.5 0.5 0.5 0.5 0.5 0.5 0.5 Resin Nylon 6,66*.sup.8 250 -- -- 260
320 320 200 Nylon 6*.sup.9 -- 250 -- -- -- -- -- Nylon 11*.sup.10
-- -- 110 -- -- -- -- (Total) (351.5) (351.5) (211.5) (361.5)
(421.5) (421.5) (301.5) (.phi.d/(.phi.m + .phi.1)) .times.
(.eta.ml/.eta.d) (at kneading) 0.26 0.23 0.50 0.26 0.25 0.25 0.26
(.phi.d/.phi.m) .times. (.eta.m/.eta.d) (Shaped 0.98 0.98 0.97 0.98
0.94 0.94 0.98 article) Air permeability .times. 10.sup.-12 4 2 10
4 5 3 4 (cm.sup.3 cm/cm.sup.2 sec cmHg) M50 (-20.degree. C.) (MPa)
48 51 25 46 46 50 41 Dynamic fatigue (-20.degree. C.) Poor Poor
Poor Poor Poor Poor Poor Notes of Table I *.sup.1IPMS (Exxon89-4)
(viscosity: 200 Pa s) made by Exxon Mobile Chemicals *.sup.2Mah-EPM
(Tufmar MP0620) (viscosity: 120 Pa s) made by Mitsui Chemicals
*.sup.3Br-IIR (Bromobutyl X2) (viscosity: 20 Pa s) made by Bayer
*.sup.4IIR (Exxon Butyl 268) (viscosity: 80 Pa s) made by Exxon
Mobile Chemicals *.sup.5PIB (Oppanol B100) (viscosity: 300 Pa s)
made by BASF *.sup.6Zinc white (Zinc No. 3) made by Seido Chemical
Industries *.sup.7Stearic acid (Beads Stearic Acid) made by NOF
Corporation *.sup.8Nylon 6,66 (UbeNylon 5033B) (viscosity: 500 Pa
s) made by Ube Industries *.sup.9Nylon 6 (UbeNylon 1030B)
(viscosity: 500 Pa s) made by Ube Industries *.sup.10Nylon 11
(Rilsan BESNOTL) (viscosity: 200 Pa s) made by ARKEMA
[0044] Viscosity of Plasticizer-Containing Nylon
[0045] Plasticizer-containing Nylon 11: 150 Pas
[0046] Plasticizer-containing Nylon 6: 170 Pas
[0047] Plasticizer-containing Nylon 6,66: 200 Pas
Comparative Examples 8 to 13
[0048] Each elastomer and the cross-linking agent were mixed by an
internal-type Banbury mixer (made by Kobe Steel Corporation) at
100.degree. C. for 2 minutes to prepare a compound, which was then
pelletized by a rubber pelletizer (made by Moriyama Seisakusho).
Pellets of the compound and the pellets of the resin were kneaded
by a twin screw kneader (made by Japan Steel Works). A part thereof
was inverted in phase and could not be kneaded due to the fact that
the rubber ratio is too high. The pellets prepared were formed into
sheets by a T-die molding machine to obtain sheets of a
thermoplastic elastomer composition. The sheets obtained were
determined for physical properties as explained above. The results
are shown in Table II.
TABLE-US-00003 TABLE II Comp. Comp. Comp. Comp. Comp. Comp.
Formulation (parts by weight) Ex. 8 Ex. 9 Ex. 10 Ex. 11 Ex. 12 Ex.
13 Elastomer IPMS*.sup.1 100 100 100 100 100 100 Cross-linking
agent ZnO*.sup.1 1.0 1.0 1.0 1.0 1.0 1.0 Stearic acid*.sup.1 0.5
0.5 0.5 0.5 0.5 0.5 Resin Nylon 6,66*.sup.1 250 -- -- 60 -- --
Nylon 6*.sup.1 -- 250 -- -- 60 -- Nylon 11*.sup.1 -- -- 110 -- --
60 (Total) 351.5 351.5 211.5 161.5 161.5 161.5 (.phi.d/.phi.m)
.times. (.eta.m/.eta.d) (shaped article, 0.98 0.98 0.97 4.10 4.10
1.78 no liquid) State -- -- -- Phase Phase Phase inversion,
inversion, inversion, poor poor poor Air permeability .times.
10.sup.-12 4 2 11 Not Not Not (cm.sup.3 cm/cm.sup.2 sec cmHg)
measurable measurable measurable M50(-20.degree. C.) (MPa) 50 51 28
Not Not Not Dynamic fatigue Poor Poor Poor measurable measurable
measurable (-20.degree. C.) *.sup.1See the notes of Table I
Comparative Examples 14 to 16
[0049] Each elastomer and cross-linking agent were mixed by an
internal-type Banbury mixer (made by Kobe Steel Corporation) at
100.degree. C. for 2 minutes to prepare a compound, which was then
pelletized by a rubber pelletizer (made by Moriyama Seisakusho).
Into the resin pellets, a plasticizer for resin (butyl benzene
sulfonamide BM-4 made by Daihachi Chemical Industry Co., Ltd.) was
added in an amount of about 30% by weight based upon the weight of
the resin and kneaded by a twin-screw kneader (made by Japan Steel
Works), then the plasticizer-containing resin obtained and the
rubber pellets were kneaded again by a twin-screw kneader (made by
Japan Steel Works) to prepare pellets of a plasticizer-containing
elastomer composition. The pellets prepared were formed into sheets
by a T-die molding machine to obtain sheets of a thermoplastic
elastomer composition. The sheets obtained were measured for
physical properties as explained above. The results are shown in
Table III.
TABLE-US-00004 TABLE III Formulation (parts by Comp. Comp. Comp.
weight) Ex. 14 Ex. 15 Ex. 16 Elastomer IPMS*.sup.1 100 100 100
Cross-linking agent ZnO*.sup.1 1.0 1.0 1.0 Stearic acid*.sup.1 0.5
0.5 0.5 Resin Nylon 6,66*.sup.1 56 -- -- Nylon 6*.sup.1 -- 53 --
Nylon 11*.sup.1 -- -- 53 Plasticizer*.sup.2 24 22 22 (Total) 181.5
176.5 176.5 (.phi.d/(.phi.m + .phi.l)) .times. (at kneading 0.92
0.85 0.89 (.eta.ml/.eta.d) and shaped article, with plasticizer)
Air permeability .times. 10.sup.-12 26 25 35 (cm.sup.3 cm/cm.sup.2
sec cmHg) M50(-20.degree. C.) (MPa) 15 16 12 Dynamic fatigue Good
Good Good (-20.degree. C.) *.sup.1See notes of Table I
*.sup.2Butylbenzene sulfonamide (BM-4 made by Daihachi Chemical
Industry Co., Ltd.)
[0050] Tire Tests
[0051] The sheets obtained were used for the following tire tests.
The results are shown in Table IV.
TABLE-US-00005 TABLE IV Comp. Comp. Comp. Ex. 1 Ex. 3 Ex. 1 Ex. 3
Ex. 14 Air leakage Pass Pass Pass Pass Fail -20.degree. C. dynamic
Pass Pass Fail Fail Pass durability test
[0052] Air leakage test: The material described in each Example
(thickness 0.15 mm) was used as an inner liner to prepare a
195/65/R15 size tire. The change in internal pressure at an initial
air pressure of 250 KPa and a 25.degree. C. atmosphere was measured
over three months. The tire was compared with a tire using a
standard inner liner of butyl rubber/natural rubber 80/20% by
weight. A tire with at least the same retention rate of internal
pressure was judged as passing, while one with less was judged as
failing.
[0053] -20.degree. C. Dynamic durability test: The material
described in each example (thickness 0.15 mm) was used for an inner
liner to prepare a 195/65/R15 size tire. This was run under
conditions of an air pressure of 120 KPa and a -20.degree. C.
atmosphere under a load of 4.8 kN on a metal drum for 30,000 km.
Thereafter, the inner liner was observed. Samples where cracks
occurred were judged as failing.
INDUSTRIAL APPLICABILITY
[0054] According to the present invention, it is possible to obtain
a flexible elastic body, while maintaining the characteristics of
the thermoplastic resins, and, therefore, for example, it is
possible to prepare an inner liner having heat resistance, low gas
permeability, chemical resistance and high dynamic durability and,
due to similar properties, it is possible to use the same for other
parts of pneumatic tires, hose inner tubes, packing, etc.
* * * * *