Laminated article from molding compositions of a chlorosulfonated polyolefin and a fluorine-containing elastomer

In accordance with this invention there is obtained a laminated article in which a chlorosulfonated polyolefin composition and a fluorine-containing elastomer composition have firmly bonded to each other by making good use of a chlorosulfonated polyolefin composition containing in particular a lead compound and a peroxide as indispensable components. In order to prepare such a laminated product a layer of chlorosulfonated polyolefin composition containing a lead compound and a peroxide as indispensable components and a layer of fluorine-containing elastomer composition are laminated by molding and then brought to vulcanizing adhesion by subjecting to the conventional process of vulcanization such as steam vulcanization in autoclave, press vulcanization, etc. The laminated article obtained in accordance with this invention is adapted for use as hoses such as fuel oil hoses of automobiles, gas hoses, etc., sheets, or other industrial goods.

FIELD OF THE INVENTION 
This invention relates to a laminated article obtained by molding a 
chlorosulfonated polyolefin composition and a fluorine-containing 
elastomer composition. More particularly, this invention relates to a 
laminated article comprising a chlorosulfonated polyolefin composition 
layer having firmly bonded thereto a fluorine-containing elastomer 
composition layer. 
Such a laminated article is useful as hoses of automobiles which are 
typified by, for instance, fuel oil hoses of automobiles consisting of an 
internal layer of a fluorine-containing elastomer and an external layer of 
a chlorosulfonated polyolefin. 
BACKGROUND OF THE INVENTION 
Fluorine-containing elastomers which are known to have peculiar properties 
because of the presence of fluorine atoms are characterized by their 
outstanding thermal resistance, oil resistance, and chemical resistance. 
For this reason, they are a material best adapted for use as hoses or 
sheets that require high thermal resistance, oil resistance, and chemical 
resistance, but their cost is too high as compared with those of other 
general rubber materials. 
Thus, it is often attempted to use fluorine-containing elastomers and other 
materials as a composite body to save the amount of the 
fluorine-containing elastomers used. 
For instance, in the case of fuel oil hoses of automobiles, it is 
considered that the internal layer coming in contact with fuel oils is 
made of a fluorine-containing elastomer, while the external layer is made 
of chlorosulfonated polyethylene which has excellent weather resistance 
and ozone resistance. 
However, fluorine-containing elastomers show very little adhesiveness 
toward chlorosulfonated polyethylene so that it was very difficult to 
stably obtain such a laminated article having a firmly bonded adhesive 
surface. Thus, it has keenly been demanded to improve the adhesiveness 
between a fluorine-containing elastomer and a chlorosulfonated polyolefin. 
SUMMARY OF THE INVENTION 
An object of this invention is to provide a laminated article obtained by 
molding a chlorosulfonated polyolefin composition and a 
fluorine-containing elastomer composition wherein a chlorosulfonated 
polyolefin composition layer and a fluorine-containing elastomer 
composition layer are firmly bonded to each other. 
DETAILED DESCRIPTION OF THE INVENTION 
The present inventors made elaborate investigations on vulcanizing adhesion 
of a chlorosulfonated polyolefin composition and a fluorine-containing 
elastomer composition and, as the result, found that firm vulcanizing 
adhesion can be obtained only by a combination of a chlorosulfonated 
polyolefin composition which contains a lead compound and a peroxide as 
indispensable components with a fluorine-containing elastomer composition 
and achieved this invention. 
That is to say, this invention is to provide a laminated article obtained 
by molding a chlorosulfonated polyolefin composition which contains a lead 
compound and a peroxide as indispensable components and a 
fluorine-containing elastomer composition. 
The term "chlorosulfonated polyolefin" as referred to in this specification 
and appended claims is a material which is obtained by chlorination and 
chlorosulfonation of a polyolefin and which contains generally from 10 to 
60 wt % of chlorine and from 0.3 to 3.0 wt % of sulfur. 
A most typical is chlorosulfonated polyethylene obtained by chlorination 
and chlorosulfonation of polyethylene. 
Besides the above, the following may also be included: chlorosulfonated 
ethylene-butene-1 copolymers, chlorosulfonated ethylene-propylene 
copolymers, chlorosulfonated ethylene-vinyl acetate copolymers, etc. that 
are respectively obtained by chlorination and chlorosulfonation of 
copolymers such as ethylene-butene-1 copolymers, ethylene-propylene 
copolymers, and ethylene-vinyl acetate copolymers as polyolefins. 
The chlorosulfonated polyolefin composition which is used in this invention 
contains a lead compound and a peroxide as indispensable components, but 
as occasion demands, there may be added compounding ingredients such as 
reinforcing agents, fillers, vulcanizing agents, crosslinking assistants, 
promoters, retarders, plasticizers, processing assistants, stabilizers, 
coloring agents, etc. 
Examples of the lead compound include tribasic lead maleate, dibasic lead 
phthalate, tribasic lead sulfate, dibasic lead phosphite, dibasic lead 
stearate, lead stearate, litharge, red lead, white lead, etc. Among them 
are preferable basic lead compounds typified by tribasic lead maleate, 
dibasic lead phthalate, and tribasic lead sulfate, because they are 
excellent in adhesiveness. 
The lead compound is added in an amount of from 2 to 100 parts by weight, 
preferably from 20 to 70 parts by weight, based on 100 parts by weight of 
the chlorosulfonated polyolefin. In the case where litharge is used, 
however, since it is difficult to vulcanize by the use of a peroxide, the 
amount of litharge to be added is preferably set up to be 20 parts by 
weight or less. 
Examples of the peroxide include dicumyl peroxide, di-t-butyl peroxide, 
t-butylcumyl peroxide, 
.alpha.,.alpha.'-bis(t-butylperoxy)-p-diisopropylbenzene, 
2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 
2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3, 
2,5-dimethyl-2,5-di(benzoylperoxy)hexane, etc. 
The peroxide is used in an amount of from 0.5 to 20 parts by weight, 
preferably from 2 to 10 parts by weight, based on 100 parts by weight of 
the chlorosulfonated polyolefin. 
In general, in peroxide-vulcanization, a crosslinking assistant having a 
double bond is very often used in addition to the above-described 
peroxide. In this invention, use of a crosslinking assistant such as 
triallylcyanurate, triallylisocyanurate, trimethylolpropane 
trimethacrylate, etc. is desirable, too. 
What is important in practice of this invention is to effect 
covulcanization of a fluorine-containing elastomer when a chlorosulfonated 
polyolefin is vulcanized in the presence of a lead compound by 
peroxide-vulcanization. If either of the lead compound or the peroxide is 
missing in the chlorosulfonated polyolefin composition, the composition 
can no longer achieve firm vulcanizing adhesion with a fluorine-containing 
elastomer composition. 
The vulcanization system of the chlorosulfonated polyolefin can generally 
be divided into the following three groups: (1) the group using 
sulfur-based vulcanization promoters typified by dipentamethylenethiuram 
tetrasulfide (TRA), tetramethylthiuram disulfide (TT), and 
ethylenethiourea (#22); (2) the group using maleimide; and (3) the group 
using peroxides. 
Even when using a lead compound in accordance with this invention, no large 
bonding strength can be obtained in the vulcanization system using no 
peroxide such as, for example, (1) or (2). 
On the other hand, even by the use of a vulcanization system containing a 
peroxide, no large bonding strength can also be obtained unless a lead 
compound is contained. Only when peroxide-vulcanization is performed by 
the use of a lead compound, chlorosulfonated polyolefin layer and a 
fluorine-containing elastomer layer can achieve firm vulcanizing adhesion. 
Examples of the reinforcing agent and filler used in a chlorosulfonated 
polyolefin composition include carbon black, white carbon, calcium 
carbonate, clay, talc, titanium oxide, etc. 
Examples of the vulcanizing agent and crosslinking assistant include metal 
oxides such as magnesia, calcium hydroxide, calcium oxide, etc. in 
addition to the abovedescribed peroxide and crosslinking assistant having 
a double bond. 
A process using a sulfur-based promoter in combination in the 
peroxide-vulcanization may also be considered, but as combination of such 
a sulfur-based vulcanization promoter causes a lowering of the bonding 
strength, it is desired to be added in an amount of 2 parts by weight or 
less. 
Examples of the plasticizer include phthalic acid esters, sebacic acid 
esters, various kinds of oils, chlorinated paraffins, etc. 
Examples of the processing assistant include low-molecular weight 
polyethylene, polyhydric alcohols, metallic soaps, etc. 
Examples of the stabilizer include nickel dibutyldithiocarbamate (NBC), 
amine- or phenol-based antioxidants, etc. 
Examples of the coloring agent include various kinds of inorganic and 
organic pigments. 
As fluorine-containing elastomer compositions, as occasion demands there 
may be added compounding ingredients, such as acid-acceptors, fillers, 
vulcanizing agents, plasticizers, processing assistants, etc. in addition 
to the fluorine-containing elastomer. 
Examples of the fluorine-containing elastomer include vinylidene 
fluoride-hexafluoropropene-based rubbers, vinylidene 
fluoride-chlorotrifluoroethylene-based rubbers, vinylidene 
fluoride-pentafluoropropene-based rubbers, etc. 
Examples of the acid-acceptor include magnesia, litharge, calcium oxide, 
etc. 
Examples of the filler include carbon black, talc, white carbon, calcium 
carbonate, clay, etc. 
Examples of the vulcanizing agent include polyamines, polyols, peroxides, 
etc. 
Examples of the plasticizer and processing assistant include silicone oils, 
stearic acid, low-molecular weight polyethylene, etc. 
There is no particular limitation to the vulcanization system and 
compounding system of a fluorine-containing elastomer composition, so that 
any of vulcanization systems and compounding systems can be used. 
There is no particular limitation to the method of lamination, and any 
processes which can place a chlorosulfonate polyolefin composition layer 
and a fluorine-containing elastomer composition layer in an intimate 
contact state prior to the vulcanizing adhesion, will suffice. For 
instance, for molding hoses double extrusion method may be employed. 
As the method for vulcanizing adhesion of lamination-molded layers of a 
chlorosulfonated polyolefin composition and a fluorine-containing 
elastomer composition, the conventional method of vulcanizing 
chlorosulfonated polyethylene such as steam vulcanization in autoclave or 
press vulcanization is carried out while bringing both layers in intimate 
contact. 
It is also possible to enhance the strength of the laminated structure by 
interposing fibers such as nylon, aramid, etc. between the 
chlorosulfonated polyolefin composition layer and the fluorine-containing 
elastomer composition layer. 
With reference to the following examples, this invention will be more fully 
explained, but it should be understood that these examples are given for 
the purpose of illustration and not limitation of the invention. 
In addition, the data used in these examples were obtained according to the 
following methods of measurement. 
Physical properties in normal state: JIS K6301 (with respect to 
press-vulcanized product) 
Peeling test: JIS K6301 
Test specimens obtained by steam vulcanization in autoclave of two test 
materials having a width of 1 inch in intimate contact with each other 
were subjected to T-peeling test at a velocity of 200 mm/min. to determine 
the adhesive strength. 
The test materials used are as follows: 
[Chlorosulfonated polyethylene] 
TOSO-CSM.RTM. manufactured by Toyo Soda Manufacturing Co., Ltd. 
TS-530 
TS-930 
TS-220 
TS-740 
Hypalon.RTM. manufactured by E. I. Du Pont de Nemours and Company. 
#40 
LD 999 
[Fluorine-containing elastomer] 
Fluorel.RTM. sold by Sumitomo 3M Limited. 
FC-2120 
FC-2174 
Tecnoflon.RTM. sold by Nippon Zeon Co., Ltd. 
THF 
Viton.RTM. A and Viton.RTM. B manufactured by E. I. Du Pont de Nemours and 
Company.