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Патент USA US2271782

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Patented Feb. 3, 1942
2,271,782
UNITED STATES PATENT OFFICE‘
VULCANIZATION 0F RUBBER
Arthur W. Sloan, Akron, Ohio, assignor' to The
B. F. Goodrich Company, New York, N. Y., a
corporation of New York
No Drawing. vApplication December‘4, 1937,
Serial No. 178,111
14 Claims. ((1260-3785)
The present invention relates to the vulcaniza
tion of rubber and rubber-like materials, and to
improvements in the process of vulcanization.
‘Of the large number of accelerators of vul
canization which have found useful. application,
thiazoles are very effective in increasing the ac
tivity of other active accelerators of vulcaniza
tion.
.
I have also found that certain ofthe amino
none has been universally applicable, so great
thiazoles, i. e. those in which the thiazole ringv is '
not fused with an aromatic ring such as a ben
and varied are the demands made upon them.
zene ring, are active accelerators in their own
It has been found possible to improve the vul
right. This is all the more surprising when it is
canizates which can be obtained by the use of
considered that Sebrell, in the article referred to
accelerators by using them in combination with
above, concluded that omission of the benzene
[ring of mercaptobenzothiazole, or substitution of
other materials which may be called activators
an amino group for the mercapto group, greatly
of the accelerators. These materials of them
diminished the activity of the compound. It now
selves may be mild accelerators, but in general
appears that both changes when made concur
they have little accelerating power When used
15 rently, instead'of having a cumulative effect in
alone.
diminishing activity, actually restore the acceler
I have found that an especially useful type of
ating power ofthe compounds.
activator is that comprising the class of primary
These materials can be made in a variety of
Z-amino thiazoles, such as Z-amino thiazole, 2
amino 4-methy1 thiazole, Z-amino 4-ethyl thia
zole, Z-amino 4.5 dimethyl thiazole, 2-amino 4
vways, for example by reacting the corresponding
20 Z-chlorderivative with ammonia preferably at an
elevated temperature, with or without a diluent
phenyl thiazole, 2-amino- 4-p-ethoxypheny1 thia
such as benzene or alcohol. They may. also be
zole, Z-amino 4-phenyl 5-methyl thiazole, 2-ami
made by reacting alpha chlor substituted ketones
nobenzothiazole, 2-amino 4 methyl benzothiazole,
Z-amino G-methoxy benzothiazole, Z-amino al 25 or aldehydes with thiourea. Phenacyl chloride,
for example,v reacts readily with thiourea in
pha-naphthothiazole, 2-amino beta-naphthothi
azole, and 2.2’ diaminobenzodithiazole. These
compounds all have the general structure repre
sented by the following formula:
aqueous suspension or in alcohol solution to form
2_-amino 4 phenyl: thiazole. Amino benzo thiazole
can be formed in good yield by reacting an excess
of ammonia with 2 chlorbenzothiazole in methyl
30
alcohol solution, under pressure at an elevated
temperature. It can also be formed by oxidizing
mono-phenyl thiourea in benzene with an oxidiz
ing agent such as chlorine or bromine, with subse
35 quent neutralization of the acid formed in the
reaction.
'in which A and B represent hydrogen or ali
Other amino thiazoles have been prepared,
phatic or aromatic radicals or a bivalent radical
largely for use as dyeintermediates, by the above
forming with the two adjacent C atoms a homo
or other methods, and may be found described in
cyclic ring. Those compounds in which A and B 40 British Patent 295,295; British Patent 347,141;
unite to form an aromatic ring fused with the '
French Patent 688,867; German Patent 537,105;
thiazole ring, such as benzothiazole, naphthothi
and United States Patents 1,787,315; 1,787,316;
azole, etc., are frequently called for convenience
and 1,788,297.
“arylene-thiazoles”. The corresponding amino
The following examples are given of the use of
oxazoles, in place of amino thiazoles, are likewise 45 certain of these amino thiazoles in rubber vul
useful.
canization where mercaptobenzothiazole is used
None of these materials has heretofore been
as the accelerator.
suggested as an activator for accelerators of vul
In a rubber composition containing rubber 100
canization. One of them has been tried as an
parts, zinc oxide 8 parts, channel carbon black
accelerator, but with negative results. For ex:
'45parts, sulfur 3 parts, pine tar 5 parts, phenyl
ample, Sebrell (Ind. and Eng. Chem. 15, 1013
beta naphthyl amine 0.75 part, and 2-mercapto
(1923)) compared Z-aminobenzothiazole as an
accelerator, with Z-mercaptobenzothiazole, and
benzothiazole 0.5-0.9 part as indicated, the addi- '
tion of the amino thiazoles listed in the table be
found the amino benzothiazole to be a very weak
low had. the e?ects noted in the table, on the
accelerator. Nevertheless the primary, Z-amino .65 rate of cure at 220° F. and at 265°'F., and on the
2,271,782
2
The generic term a rubber is meant to desig
nate generally rubbery materials susceptible of
aging in an oxygen bomb for 96 hours at 70° C.
and 300 lbs. of oxygen pressure.
Mermp
tobenzo
_
Amino thiazole
_
I
Tensile of
Tensile
T°nS§12%§nF6° @ _ cggglgl'i'géo
thiazole
'
F.
1:521?)
aging
0. 9
None _____________________ __
2, 075
0.9
0. 9
0.2 2-aminobenzothiazole__..
0.4 Z-amino 4.5-dimetl1ylthiazole.
0.4 2-amino 4.5-dimethyl
thiazole.
2, 400
3, 025
0.2 2aminotl1iaz0le _______ _0.4 2-aminothiazole _______ __
2,900
2, 300
0. 9 0.2 2-amino 4-ethylthiazole__
0. 9 0.4 Z-amino 4-phenylthiazole.
2, 750
2, 780
0. 7
0.9
0.5
2, 940
vulcanization with sulfur, such as caoutchouc,
abalata, gutta percha, natural or arti?cially
prepared latex, and synthetic rubber.
It will be noted that the rate of vulcanization
has been increased by the addition of the amino
thiazole and that by its use, the amount 'of ac
celerator can be reduced without lowering the
It is to be understood that the activators may
rate of vulcanization; also that the ultimate ten 20 beused in admixture with antioxidants, sof
teners, pigments, ?llers, etc. ; and that the rub
sile strength of the rubber is increased, that the
ber may be vulcanized with the assistance of this
increased rate of vulcanization and improved
new class of activators in other manners than
tensile strength are accomplished without in
that particularly set forth above; speci?cally, it
creasing the “scorchiness” of the rubber mix
ture—i. e. the tendency to precure as reflected 25 may be vulcanized in hot air, steam, hot water,
etc. The activators may be advantageously em
by the rate of vulcanization at 220° F.-—and that
ployed in small proportions, usually not more
‘the vulcanizates containing the aminothiazoles
than 1% of the rubber in the compositions‘.
age better in the Bierer-Davis bomb at 70° C.
Amounts as high as 5% or over may be used,
'under 300 lbs. oxygen pressure than do the vul
however.
canizates lacking the amino thiazoles. Similar
For the purposes of this patent, the two
results are secured with other mercaptothiazoles,
isomeric formulas
particularly the mercapto alkylthiazoles such as
VZ-mercapto 4,5 dimethyl thiazole.
2-41
Other active accelerators, such as the esters
of mercaptobenzothiazole, the aldehyde-amines,
the guanidines and the thiurams (salts, esters,
35
sul?des, etc.) are likewise activated by these
materials, but in general the so-called basic ac
are considered as being equivalent or identical.
celerators such as the guanidines and aldehyde
The'scope of this invention is not to be limited
amines are less sensitive to their presence than 40 to the speci?c examples herein set forth, but is
the so-called acidic type of accelerator including
to be- limited only as required by the prior art
the mercaptothiazoles, as well as other mercapto
and as indicated in the appended claims.
‘substituted organic bases such as 'mercapto
I claim:
quinoline, and the accelerating thio acids such
1. The process of vulcanizing a rubber in the
as dithiobenzoic acid, xanthogenic acids, dithio
presence of an active accelerator of vulcanization
carbamic acids and the like, and salts, esters,
of the acidic type and as an activator therefor
acid anhydrides, disul?des, and other derivatives
a primary 2-amino thiazole.
of the types well known to be active accelerators
2. The process of vulcanizing a rubber in the
of vulcanization, of any of them,
presence of an active accelerator of vulcaniza
These amino thiazoles in which the thiazole
tion of the acidic type and as an activator there
iringe is not fused with an aromatic ring are use
ful alone as accelerators. For example, 2-amino
for 2-amino benzothiazole.
3. The process of vulcanizing a rubber in the
thiazole, 2-arnino 4-methyl thiazole, 2-amino
presence of 2-mercapto benzothiazole and as an
4-ethyl thiazole, and 2-amino 4,5-dimethyl
activator therefor 2-amino benzothiazole.
thiazole are accelerators of moderate activity 55
4. The process of vulcanizing a rubber in the
as indicated by the following data:
presence of a primary 2-amino thiazole in which
A rubber composition containing rubber 100
the thiazole ring is not a part of a fused ring
parts, zinc oxide 10 parts, sulfur 3.5 parts,
barytes 20 parts, and 2-aminothiazole 1 part,
when vulcanized for 90 min. at 287° F. gave a
vulcanizate having a tensile strength of 3455
lbs/sq. in. and an ultimate elongation of 700%.
In contrast with this result, a rubber com
system.
60
5._ The process of vulcanizing a rubber in the
presence of a primary Z-amino alkyl-substituted
thiazole.
6. The process of vulcanizing a rubber in the
presence of an active accelerator of vulcaniza
position containing rubber 100 parts, zinc oxide 65 tion of the acidic type and as an activator there
for a primary Z-amino thiazole in which the
'10 parts, sulfur 4 parts, and anilinobenzothiazole
thiazole ring is not a part of a fused ring system.
1 part, when vulcanized for 90 min. at 287° F.
7. The process of vulcanizing a rubber in the
gave a vulcanizate having a tensile strength of
presence of an' accelerating mercapto hetero
only 1465 lbs/sq. in., and an ultimate elongation
of 965%, indicating that very little cure had 70 cyclic base and as an activator therefor a pri
mary 2-amino thiazole.
taken place.
8. The process of vulcanizing a rubber in the
By replacing the anilinobenzothiazole with
presence of a Z-mercaptothiazole and as an
2-aminobenzothiazole, a tensile strength of 1890
activator therefor and a primary 2-amino
lbs/sq. in., and an ultimate elongation of 880%
.
75 thiazole.
were obtained.
'
2,271,782
3
9. The process of vulcanizing 'a rubber in the
which has been vulcanized in the presence of a
presence of a 2-mercapt0thiazo1e and as an
primary 2-amino thiazole in which the thiazole
activator therefor Z-aminothiazole.
10. The process of vulcanizing a rubber in the
ring its not a part of a fused ring system. I
presence of a Z-mercapto alkylthiazole and. as
an activator therefor 2-amino alkylthiazole.
11. A rubber composition comprising a rubber
13. A rubber composition comprising a rubber
which has been vulcanized in the presence of a
2-mercapt0 alkylthiazole and as an activator
therefor a primary 2-amino thiazole.
which has been vulcanized in the presence of an
14. A rubber composition comprising a rubber
active accelerator of vulcanization of the acidic
which has been vulcanized in the presence of a
type ‘and as an activator therefor a primary 10 2-mercapto alkylthiazole and as an activator
Z-amino- alkyl thiazole.
12. A rubber composition comprising a rubber
therefor Z-amino alkylthiazole.
ARTHUR W. SLOAN.
CERTIFICATE OF CORRECTION‘.
Patent No. ‘2,271,782.
'
ARTHUR w.
_
February 5, 19h2‘.
sLoAN'. .
It is hereby'qer?ified that error appéafs in‘ the printed SReQificatiOn
offhe above numbevrr'ed patent requiring gorrection'aafqllowé: Page 2, first
column,v 11ne_50., for the word ,"T_hese".revad' —'-Thosie-'-; line 513 ~|for "rin’ge"
re_ad "ring"; and second» cblumn',_1:'[ne'_ 17', forfabalrataWnead --ba1ata--;_
line 711., 01511118, Strikeout "and" after_"'there£'c_>r"'; pag'eE, second dolumn,‘
line 5, claim '12,‘ £01‘ "its? read --'is-'-;; and thét vtnmsRid“Lettéz-s'mvcent'
should be read with this cd rf'ec’u 6n thereimthat [the lséme may conform to
‘the'recordvof the case in the Patent office. '
Signed and sealed this 1st day of De‘qe'mbfér,
D. 19142.1,
Henry Van Arsdal'ew,
(Seal)
Actingicomr'niss‘idngr o_f Patent-s,
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