FR2494295A1 - TREATED BLADDER FOR VULCANIZATION OF PNEUMATIC OR SEMI-PNEUMATIC ENVELOPES OR BANDAGES, TREATMENT COMPOSITION THEREFOR AND METHOD FOR VULCANIZATION OF ENVELOPES - Google Patents

Abstract

LUBRICATING COMPOSITION CONSISTING OF CLAY, TWO POLYDIMETHYLSILOXANES, POLY (ETHYLENE GLYCOL ETOU PROPYLENE GLYCOL) AND ONE OR MORE SURFACTANTS. BLADDER FOR VULCANIZING ENVELOPES BY PNEUMATIC TAPES, COATED WITH THIS COMPOSITION; PROCESS AND METHOD FOR MOLDING A RUBBER COVER USING THIS COATED VULCANIZATION BLADDER PROCEDE.

Description

The present invention relates to compositions for

  drifts for the vulcanization bladders of envelopes, or bandages, of the vulcanization bladders of envelopes coated externally with these lubricating compositions and a method of vulcanization of the envelopes using a bladder thus coated.

  Pneumatic rubber casings or tires

  Heads for vehicles are usually made by mold-

  ge and vulcanization of a raw shell, or unvulcanized and unshaped, in a molding press

  the raw envelope is pressed outward against the surface

  that of a mold by means of a bladder expandable by an internal fluid. By this process, the raw envelope is shaped against the surface of the external mold which defines the design of the strip.

  tire tread and sidewall configuration.

  The envelope is vulcanized by heating. In general, the ves-

  sie is expanded by the internal pressure of a fluid such as hot gas, hot water and / or steam, which participates

  also the heat transfer necessary for vulcanization.

  The tire is then allowed to cool a little in the mold.

  it, sometimes helping this cooling by introducing cold or cooler water into the bladder. Then we open the mold, the bladder deflates by releasing the pressure of

  its internal fluid, and the envelope is removed from the envelope mold

  loppes. This use of the vulcanization bladders of

  Veloppes is well known to specialists.

  It is known that there is a significant relative movement between the outer contact surface of the bladder and the inner surface of the envelope during the expansion phase of the bladder before the complete vulcanization of

  the envelope. Similarly, there is a relative movement consi-

  maple between the outer contact surface of the bladder and the vulcanized inner surface of the envelope after

  the envelope was molded and vulcanized, during the deflation

  ment and extraction of the bladder from the envelope.

  If adequate lubrication is not provided for

  be the bladder and the inner side of the envelope, the bladder has

  generally tend to curl, which in turn does not cause

  formation of the envelope in the mold and also has the effect of excessive wear and roughening of the surface of the bladder itself. In addition, the surface of the bladder can

  tend to stick to the inside of the envelope when

  that the envelope is vulcanized and during the stage of the vulcanization cycle of the envelope during which the bladder deflates. In addition, there is a potential risk of entrapment

  air bubbles between the surfaces of the bladder and the

  veloppes, these bubbles promoting vulcanization defects

  envelopes due to the absence of a heat transfer

their adequate.

  For this reason, it is conventional to pre-coat with a lubricant the internal face of the shell, whether raw or not.

  vulcanized to provide lubrication between the face ex-

  dull bladder and the inner face of the envelope during the operation of shaping and molding the envelope. The

  lubricant is sometimes referred to as "cheer cement"

  lining cement. Usually the inner side of the raw shell, which is usually a rubber compound, is simply spray coated in a closed spray booth with a lubricant that can

  for example be based on silicone polymer. We can also

  if using in the lubricant composition other addi-

  tif such as mica, polymer polyols, ether ethers

  lulosics, a clay such as bentonite etc ... Some lubricants are solvent-based and others are based

  of water. Aqueous solutions of soaps are often used.

  Numerous lubricating compositions intended for this application

  have been described in the art.

  However, the classic practice of covering

  spraying the internal face of the green envelope of a lubricating composition can constitute an operation requiring a relatively large workforce, which can

  add appreciably to the cost of production of the

  veloppe. The envelope must be brought into the pulp booth

  and removed from it, and leave it to the

  spray lubricant time to dry.

  It is therefore desirable to have an improved lubrication system with regard to its composition and

  its use for molding or shaping and vulcanizing

nization of raw envelopes.

  In accordance with the invention, there is provided a

  lubricating position resulting from mixing:

  (A) from about 10 to about 40, preferably about

  from 25 to about 35 parts by weight of bentonite having a particle size of from about 0.149 to about 0.03 mm, preferably from about 0.074 to about 0.037 mm;

  (B) from about 15 to about 45, preferably about

  ron 25 to about 35 parts by weight of a pol-ydimethylsilo-

  xane characterized in that it has a viscosity in the

  tervalle from about 15 million to about 25 million cent

tistokes at 25 C;

  (C) from about 15 to about 45, preferably about

  about 25 to about 35 parts by weight of a polydimethylsilo-

  xane characterized in that it has a viscosity between

  about 40,000 and about 120,000, preferably between about

  ron 50,000 and about 70,000 centistokes at 25 C;

  (D) from about 12 to about 36, preferably about

  about 20 to about 30 parts by weight of a poly (ethylene

  glycol and / or propylene glycol), characterized in that it pos-

  sedes a molecular weight in the range of about 1,500 to about 2,200;

  (E) from about 10 to about 25, preferably dten-

  about 15 to about 20 parts by weight of surfactants for these polydimethylsiloxanes and this poly (alkylene glycol); and

  (F) if desired, from about 4 to about 12 per-

  parts by weight of a stabilizer relative to the total of the poly-

  dimethylsiloxanes. The composition intended for application to the surface of the bladder is an emulsion or an aqueous dispersion of

  compositions. For example, the application composition

  also holds (D) about 500 to about 1500, preferably between-

  about 600 to about 800 parts by weight of water which, after application to the bladder, is eliminated by evaporation. We

  can certainly use more water, although a dilute

  additional composition reduces effectiveness

of its application.

  It is generally preferred that the polydimethylsiloxane of (B) or (C) carries hydroxyl end groups, as an ingredient for the preparation (precursor) of the composition The poly (alkylene glycol) of (D) is chosen from a poly ( ethylene glycol), poly (propylene glycol) or their

  mixed. Poly (propylene glycol) is preferred.

  The invention further relates to a vulcanic bladder

  expansion of expandable rubber covers, coated with

  this coating composition (in particular after removing

  water nation). In practice, the rubber constituting

  the bladder is generally a butyl rubber or of the bu type

  tyle (copolymer of isoprene and isobutylene). By

  "butyl type rubber" means various rubbers

  modified base tyle such as butyl rubbers

  killed by halogens, for example chloro-

butyl or bromobutyl.

  The invention also relates to a method for preparing

  ration of a pneumatic or semi-pneumatic rubber jacket

  material consisting in placing in a tire mold, a green envelope in which is arranged an expandable bladder of the invention, in closing the mold and in expanding the bladder by introduction of a hot fluid inside thereof, for

  force the envelope outward against the surface of the mold

  so as to shape and vulcanize the envelope, after which the mold is opened, the bladder is deflated and the envelope is removed

shaped and vulcanized frame.

  Such a process for molding a pneumatic casing

  that or semi-pneumatically more precisely understands the operations

  following statements: (A) we obtain or build a raw envelope comprising elements which will form its tread

  external intended to come into contact with the ground, two uneven heels

  separate tensiles, sides extending radially outward

  from the heels to join the tread

  ment, a support carcass with reinforcing elements, and an inner face of rubber mixture;

  (B) this raw envelope is introduced into a press-

  is molded for envelopes and there is a vulva bladder

  ducting of the envelopes, coated in accordance with the invention inside the raw envelope, the bladder being fixed to an internal part of the envelope press; (C) the envelope mold is closed and the vulcanization bladder of the envelopes is expanded outwards

  coated, by means of a heated internal fluid, against sur-

  face of the inner rubber mixture of the casing for

  wrap the envelope outwards in temperature conditions

  erasing and pressure making it possible to shape and vulcanize the envelope; (D) we open the envelope mold, we deflate the

  bladder and the vulcanized shell which has

usually a toroidal shape.

  The expression "pneumatic envelope" designates envelopes whose correct operation, when mounted on a rim, is based on an internal fluid such as

  pressurized air in the envelope cavity and the ex-

  "semi-pneumatic" pressure means envelopes which

  hold an internal fluid, such as air, in their cavity

  but which do not completely depend on its pressure to function properly when mounted on a rim.

  It is important to realize that various

  diapers or lubricant compositions were evaluated before the discovery and use of the composition of the invention

  for bladder coatings for envelopes.

  For example, lubricant compositions have been evaluated

  fiants containing a silicone compound, based on or-

  ganiques. However, difficulties have been encountered apparently due to the fact that the organic solvent of the composition ends up damaging or degrading the surface of the rubber of the bladder.

  herself. The organic solvent poses problems.

  my flammability and toxicity potentials. We observed

  furthermore that the coating compositions based on sol-

  assessed organic wings, deposited on the vulcanic bladder

  only had a useful life of around 4 to 6 cycles

  vulcanization of the envelopes until it is consi-

  dere as necessary or useful to re-coat the surface of the

  bladder. This frequency of re-coatings is considered to be

  presenting me with a marginal economic advantage taking into account

potential hazards that are related.

  In the practice of the invention, the emulsion or dis-

  aqueous persion of the lubricating composition can be obtained

  conveniently bare by the process of (A) mixing under high shear mixing conditions about 10 to about 40, preferably about 35, parts by weight of a bentonite having a particle size of between about 0.149 and about 0.03 mm, preferably between about 0.074 and 0.037 mm, with

  about 500 to about 1500, preferably about 600 to about

  ron 800 parts by weight of water at a temperature between-

  be about 20 C and about 95 C, the water preferably being preheated to a temperature of about 50 to about 80 C, until the mixture appears thickened; (B) mix with this suspension, under high shear conditions, about 15 to about 45, preferably

  about 25 to about 35 parts by weight of a polydimethylsi-

  loxane characterized in that it has a viscosity included

  between about 15 million and about 25 million centis-

  tokes at 25 C, and about 3 to about 25 parts by weight of a-

  gent active surfactant for this polydimethylsiloxane; (C) mix with the composition obtained approximately 15 to approximately 45, preferably approximately 25 to approximately 35 parts in

  weight of a polydimethylsiloxane characterized in that it pre-

  feels a viscosity between about 40,000 and about 000, preferably between about 50,000 and about 70,000 centistokes at 25 C, about 12 to about 36, preferably about 20 to about 30 parts by weight of a poly (ethylene glycol and / or propylene glycol) characterized in that it has a molecular mass of between approximately 1500 and approximately 2500, preferably between approximately 1800 and approximately 2200, and approximately 4 to approximately 10 parts by weight of surfactant for this polydimethylsiloxane and this poly (alkylene glycol);

  (D) mix if desired with the composition obtained

  about 2 to about 10 parts by weight of a surfactant

  active to reduce the friction between the bladder and the tire

matic;

  (E) mix if desired with the composition obtained

  about 2 to about 8 parts by weight of a corrosion inhibitor;

  (F) mix if desired with the composition obtained

  naked about 0.2 to about 1.0 parts by weight of anti-agent

foam;

  (G) mix if desired with the composition obtained

  bare about 2 to about 10 parts by weight of stabilizer.

  It should be noted that various relatively good anti-foam agents can be used in the practice of the invention.

  known and various stabilizers which are generally well known

naked specialists.

  The aqueous emulsion or dispersion is simply ap-

  plicated, for example by spraying, on the bladder and el-

  the is dried by evaporation at a temperature which is

  example in the range of about 20 "C to about 110 OC.

  It is preferred that the bladder, for this application, be at-

  about 80 - 150% of his postion or dilated state for the

  vulcanization of the envelope (and not in the deflated or af-

  collapsed), although this is not considered necessary and bladders have been successfully coated in a state

somewhat deflated.

  It should be noted that various compositions of

  brifiant in emulsion or aqueous dispersion, based on silico-

  ne or siloxane, have been previously formulated and eva-

  read as coatings for vulcanization bladders. In fact,

  such a composition has been previously tried with the fluid

  of viscous polydimethylsiloxane (C). With this composition

  tion, we have experimentally found that when a rubber bladder is coated with it, only 6 to 9 envelopes can be molded with this bladder (6 to 9 vulcanization cycles

  envelopes) until excessive adhesion develops

  manifest between the outer contact surface of the bladder and the inner surface of the envelope, resulting in

  their tendency to stick excessively to each other when

  inflation of the bladder after vulcanization of the envelope. AT-

  upon addition to the blend of the viscous polyorganosiloxane polymer, it has been found that about 10 to about 15 casings can be shaped and molded with the bladder (10 to 15 cycles) before excessive adhesion occurs

(bonding) between surfaces.

  An important feature of the composition of

  lubricant is obviously the presence of two types of poly-

  Polydimethylsiloxane mothers (from B and C) which comprise both a polymer of high viscosity and a fluid having a certain viscosity. It should be noted, however, that a coating made of these materials has been found to be a little greasy unless bentonite is also used, which tends both to combat the greasy appearance of the surface of the surface. coated bladder, and also, apparently, to a large extent allow potentially trapped air to escape from the

  area. Soap or additional surfactant is optional.

  tative can be beneficial because it can apparently increase

  the slip between the bladder and the envelope.

  The optional defoaming agent may be

  an aqueous emulsion of polydimethylsiloxane which is advan-

  tagger because it prevents or inhibits the formation of foam

during mixing.

  The following nonlimiting examples are given at

  title of illustration of the invention. Unless otherwise stated

  res, parts and percentages are all by weight.

EXAMPLE I

  A lubricant composition is prepared according to the form

mule shown in Table I.

TABLE I

  Material Parts Bentonite clay (0.044 mm) 31.2 Water 712.1 Polydimethylsiloxane (at the ends of hydroxyl chairs) 42.8 Polydimethylsiloxane2 62.8 Surfactant3 6.25 Corrosion inhibitor (sodium benzoate) 5 Defoamer 0 , 33 stabilizer 6.25

  1. Indicated as being a polydimethylsiloxane having a vis-

  cosity of the order of 20 million centistokes in one met

  diaper consisting of approximately 31.3 parts of polydimethylsi-

  loxane and about 11.6 parts of surfactant therefor.

  2. Indicated as a viscous polydimethylsi- fluid

  loxane having a viscosity of about 60,000 centistokes

  in a mixture of about 31.3 parts of this pot-

  lydimethylsiloxane, of about 25 parts of polypropylene

  glycol having a molecular weight of about 200 and of

  about 6.3 parts of surfactant therefor.

  3. Sodium soap from a vegetable oil, considered as fa-

  cultivation. The aqueous emulsion was prepared according to the following procedure: (A) heating the water to a temperature of about 60 ° C. and adding the clay. Mix at 2500 rpm in a Cowles mixer for about 2 to 5 minutes, during which the appearance of the mixture indicates

that it has thickened.

  (B) add the mixture of polyorgano- polymers

  siloxane under high shear at 2500 rpm.

  to prepare an aqueous emulsion.

  (C) Add the viscous fluid mixture of olvoraano-

  siloxane and polyglycol by mixing under high shear.

  (D) add the additional surfactant.

  (E) add the corrosion inhibitor intended to pro-

the application device.

(F) add the silicone defoamer.

  (G) add the stabilizer at a rate of 10% of the to-

  tal of polysiloxane and siloxane concentrate

(B and C).

  The mixture is applied by spraying on the face

Z494295

  outer of the vulcanization bladder of the rubber casings

  cabbage kept in the expanded state. Let the coating dry

  about 65 ° C. The coating is reapplied after approx.

  ron 4 cycles of vulcanization of envelopes, with a maximum of 4 hours between coating applications. The coating is dried for about one minute on the hot surface (65 ° C.) of the bladder to form on

  the latter a coating of lubricant composition.

  The bladder itself is butyl rubber, its

  general shape is torofdale with an overall diameter in the

  expanded state of approximately 990 mm and a tubular diameter of approximately 250 mm. Its surface has been pretreated by washing with a solvent

  hydrocarbon then drying to remove superficial oils

skies etc ...

  We make a raw radial envelope of dimensions

it R 22.5.

  Place the envelope in an envelope mold

  and the coated bladder is inserted inside the envelope.

  kills, fixed to the mold. The mold is closed and the bladder is dilated with steam at approximately 190 OC to apply it strongly against the internal surface of the envelope and press the face

  outer shell to shape the envelope in the

* re desired and vulcanize it.

  Then open the mold, deflate the bladder and remove the envelope. By doing so, we observe that we can mold about 10 to about 15 envelopes with the

  bladder in about 8 to 13 hours (vulcanization cycles) a-

  before it is necessary to reapply

lubricating position on the bladder.

  Generally speaking, a new application is

  considered necessary when the bladder sticks exaggerated-

  lying on the inner side of the vulcanized shell when the

  dilated bladder is deflated after the vulcanization operation

  tion. The inner face of the envelope is generally a

  rubber mixture which may consist of various rubber

  cabbages such as natural rubber, cis-1,4-polyisopre-

  ne, cis-1,4-polybutadiene, butadiene-sty-

  rene, butyl rubber, halo-butyl rubbers, for example chlorobutyl and bromobutyl rubbers and EDPT (terpolymer of ethylene, propylene and a small amount

dtun diene).

  In this example, we describe the preparation of a

  Velcup with radial carcass. Although the invention may often

  be considered more adaptable to the production of

  envelopes with radial carcass than with carcass envelopes di-

  gonal, because the bladders generally have to expand more during the vulcanization cycle of the casings with a diagonal carcass, which stretches the surface coating of

  the bladder, onK considers that the invention is entirely acceptable

  table for the production of envelopes with a diagonal carcass

  and is not limited to the manufacture of casings

gets radial.

  It is important to note that the envelope of this

  example was made by directly expanding the bladder re-

  clothed against the inner surface of the rubber compound of the

  Velcro to press the envelope outwards in

  temperature and pressure conditions allowing

  blow and vulcanize. The coated bladder actually

  allowed to prepare the envelope without applying a coating

  lubricant or liner cement on the face

  internal of the raw envelope. This fact is considered im-

  bearing, because it clearly shows that the bladder coated according to the

  vention provides adequate lubrication for a range of

  successive cycles of vulcanization of the envelopes in con

  temperature and pressure, expansion and con- dition

  traction, without prior application of lining cement

  or conventional lubricant on the internal face of the envelope.

  We can reasonably consider that this will allow

  considerable labor and material in the preparation of pneumatic casings. Although it is recognized that a pre-coating of lubricant can be used, if desired, on the internal face of the green envelope, in

  association with the coated bladder, it is considered important

  as long as this example demonstrates that this is not necessary.

Claims (16)

R E V E N D I C A T I 0 N S   1 - Lubricating composition, characterized in that that it includes: -   (A) about 10 to about 40 parts by weight of a bentonite having a particle size of about 0.149 to about 0.03 mm; (B) about 15 to about 45 parts in   weight of a polydimethylsiloxane characterized in that it pre-   feels a viscosity between about 15 million and   about 25 million centistokes at 25 C; (C) about 15 to about 45 parts in   weight of a polydimethylsiloxane having a viscosity in the   tervalle from about 40,000 to about 120,000 centistokes at C; (D) about 12 to about 31 parts in   weight of a poly (ethylene glycol and / or propylene glycol), ca   characterized in that it has a molecular mass of between approximately 1500 and approximately 2500; (E) about 10 to about 25 parts by weight of surfactants for polydimethylsiloxanes and poly (alkylene glycol); (F) possibly about 4 to about 12 parts by weight of stabilizer.   2 - Lubricating composition according to claim   1, characterized in that at least one of the polydimethylsilo-   xanes of (B) and (C) carry terminal hydroxyl groups.   3 - Composition according to claim 1, charac-   terized in that the poly (alkylene glycol) is poly (pro- pylene glycol).   4 - Composition according to claim 3, character-   laughing at the fact that the polydimethylsiloxane of (B) carries groups pes hydroxyl terminals.   - Lubricating composition according to claim 1, characterized in that it is an aqueous emulsion   containing about 500 to about 1500 parts of water by weight.   6 - Lubricating composition according to the claim   tion 2, characterized in that it is an aqueous emulsion   containing about 500 to about 1500 parts by weight of water.   7 - Composition according to claim 4, charac-   t6risée in that it is an aqueous emulsion containing   about 500 to about 1500 parts by weight of water.   8 - Composition according to claim 5, charac-   terized in that it contains about 500 to about 1500 parts by weight of water.   9 - Vulcanizing bladder for envelopes or ban-   vulcanized, expandable rubber dages, characterized in that   that it carries a coating of the composition according to the   vendication 1 on its exposed external face.   10 - Vulcanizing bladder for butyl rubber or vulcanized butyl type envelopes, expandable, in toroidal form, for a pneumatic or seri-pneumatic bandage,   characterized in that it carries a coating of the composition   tion- according to claim 2 on its outer face.   11 - Vulcanization bladder for butyl rubber or vulcanized butyl type envelopes, expandable, for a pneumatic or semi-pneumatic tire, characterized in that it carries a coating of the composition according to the   claim 3 on its outer face.   12 - Vulcanizing bladder for expandable vulcanized rubber envelopes, characterized in that it   bears a coating of the composition according to the claim tion 4 on its external face.   13 - Process for preparing the following composition   before any one of claims 1 to 3, characterized   in that (A) mixing under high shear conditions about 10 to about 40 parts by weight of a bentonite having a particle size of about   0.149 to about 0.03 mm with about 500 to about 1500 par-   parts by weight of water preheated to a temperature between about 20 and about 95 C until the mixture appears thickened; (B) about 15 to about 45 parts by weight are mixed with this suspension under high shear.   of a polydimethylsiloxane characterized in that it has a screw-   cosity between around 15 million and around 25 million-   centistoke lions at 25 C and about 3 to about 25 par-   parts by weight of a surfactant for this polydimethyl- siloxane;   (C) mixing with this composition approx.   ron 15 to about 45 parts by weight of a polydimethylsiloxane   characterized in that it has a viscosity of between approx.   ron 40,000 and about 120,000O centistokes at 25 C, about 12 to about 36 parts by weight of poly (ethylene glycol and / or   propylene glycol), characterized in that it has a molecular mass   approximately 1500 to approximately 2500, and approximately 4 to approximately   parts by weight of a surfactant for the polydime-   thylsiloxane and alkylene oxide polyol; (D) mixing, if desired, about 2 to about 10 parts by weight of additional surfactant with this composition; (E) mixing if desired with this   composition about 2 to about 8 parts by weight of inhibitor   corrosion erector; (F) mixing, if desired, with this composition about 0.2 to about 1.0 part by weight of anti-foaming agent; (G) mix if desired with this   composition about 2 to about 10 parts by weight of sta- biliary.   14 - Method for treating a vulcanic bladder   for vulcanized rubber envelopes, expandable in toroidal form, expandable, for a pneumatic tire or   semi-pneumatic, characterized in that the surface is ex-   posterior, exposed from the bladder, about 80 to about 150%   from its expanded position of vulcanization of the envelopes with the   of the composition in the form of the following aqueous emulsion   any of claims 5 to 7, and in that it is   che this composition by evaporation.   - A method of molding an envelope or tire of pneumatic or semi-pneumatic rubber, characterized in that it consists of   (A) procure or construct an envelope   raw eg comprising elements intended to form its strip of   external bearing which will be in contact with the ground, two ta-   separate inextensible lons, sides extending radially outward from the heels to join the tread, a support carcass with elements of   reinforcement, and an inner surface of rubber compound   cabbage; (B) introduce the raw envelope into an envelope molding press and arrange a bladder of   vulcanization of the envelopes according to any of the   vendications 9, 10 and 11 inside the raw envelope, the bladder being fixed to an internal part of the envelope press;   (C) close the envelope mold and dilate   ter the bladder coated with vulcanization of the envelopes, by means of an internal, heated fluid, against the   envelope rubber compound surface, to press the   expands outward under temperature and pressure conditions to shape and vulcanize the envelope;   (D) open the envelope mold,   fling the bladder and remove the vulcanized envelope having a general toroidal shape.   16 - Process for molding an envelope or tire of pneumatic or semi-pneumatic rubber, characterized in that   (A) we get or build a   raw veloppe comprising elements intended to constitute its external tread which will be in contact with the ground,   two separate inextensible heels, flanks extending short   dial outwards from the heels to reach   the tread, a support carcass with elements   reinforcing elements and an internal surface of rubber compound; (B) the raw envelope is introduced into an envelope molding press and a vulcanization bladder of the envelopes is arranged according to any one of the   claims 12 and 13 inside the raw envelope, the   bladder being attached to an internal part of the envelope press   loppes; (C) the envelope mold is closed and the vulcanization coated bladder of the envelopes is expanded outwards by means of an internal fluid heated against the   mixture of internal rubber of the envelope to press the envelope   pops outwards under temperature and pressure conditions allowing the shaping and vulcanization of the envelope;   (D) we open the envelope mold, we   inflate the bladder and remove the vulcanized envelope which has generally a toroidal form.   17 - Process for molding a rubber casing -   pneumatic or semi-pneumatic chouc, characterized in that:   (A) we get or build a   raw veloppe comprising elements intended to constitute its external tread which will be in contact with the ground,   two separate inextensible heels, flanks extending short   dial outward from the heels to reach   the tread, a support carcass with elements   reinforcing elements and an internal surface of rubber compound; (B) the raw envelope is introduced into   an envelope molding press and we have inside   laughing of the raw envelope a vulcanization bladder   envelopes according to any of claims 9, 10   and 11, the bladder being fixed on an internal part of the envelope press; (C) close the envelope mold and   expands the bladder outward with a warm fluid   internal fairy, the lining of the bladder being directly con-   be the inner surface of the envelope to press the envelope   eg outward under temperature and   pressure to shape and vulcanize the envelope.   18 - Process for molding a rubber casing -   pneumatic or semi-pneumatic chouc, characterized in that   (A) we get or build a   raw veloppe with elements that will constitute its ban-   of external rolling intended to be in contact with the ground, two separate inextensible heels, sidewalls extending   radially outwards from the heels to reach   dre the tread, a support carcass with reinforcing elements and an internal surface of rubber compound; (B) the raw envelope is introduced into an envelope molding press and a vulcanization bladder of the envelopes is arranged according to any one of the   claims 12 and 13 inside the raw envelope,   the bladder being fixed on an internal part of the envelope press; (C) the envelope mold is closed and the bladder is expanded outward using an internal fluid   heated, the lining of this bladder being directly con-   tre the inner surface of the envelope to press the envelope outward under temperature and   pressure to shape and vulcanize the envelope.