DE2427029A1 - WATER BASED LUBRICANT - Google Patents

Description

Or. Horst Schüler

Patent attorney
6 Frankfurt / Main 1

Niddastr. 52

4th June 1974 Dr. Sb./Cs 2715-8SI-1412

GENERAL ELECTRIC COMPANY

1 River Road Schenectady, N.Y., U.S.A.

Water-based lubricants

The present invention relates to a composition for lubricating an expandable core during the molding of tires. More particularly, the present invention relates to a silicone holder ige water-based emulsion composition which is a particulate includes solid material to create channels to pass between the expanding during vulcanization Core and the still unvulcanized tire to absorb trapped air.

In US Pat. No. 2,937,406, the pressure bag process is general (referred to in English as "fluid pressure core technology") that is used in the industry for hardening new Tires and for giving old tires a new profile is applied. This technique uses fluid

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Pressure cores, such as fully circular or section-shaped air sac bubbles and the like introduced into the uncured or "green" tires and like articles during vulcanization the. bringing the outer surface of the article into contact with the mold and applying pressure to it. According to the above US patent it is critical to control the interface between the outer surface of the bag and the inner surface of the tire lubricate, especially below the shoulder areas of the sack, because of the large frictional forces developed. If no discharge of these forces then lead to a considerable one Reduction of the tire size in this key area and may cause premature damage to the bag. In the aforementioned US patent is proposed this Overcome friction by making integrally lubricated rubber layers forms in the air bag. However, this is difficult and can only be achieved at high cost. Another means of lubrication of an unvulcanized tire and to separate the sack in US Pat. No. 3,532,624, according to which a composition which is a silicone liquid, a polyol, particulate Mica and 25-55 weight percent of a hydrocarbon solvent is sprayed on the surface of a conventional sack, i.e. one which does not have any lubricated streaks includes just before you put it in the unvulcanized Lets tire stretch. All hydrocarbon solvents are flammable, many are toxic, and most are toxic

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air / water pollution, making them difficult to throw away are. Exemplary of such volatile flammable Toxic solvents of the known type as described in U.S. Patent 3,532,624 are those described below boil from 2OO ° C, such as cyclohexene, toluene. Gasoline, petroleum naphtha and similar.

The tire industry therefore has an identified need for - an easily applicable, effective and non-polluting, ianer-

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lubricant to be used in semi-unvulcanized tires and Release agent. An ideal agent should extend the useful life of the bladder, effectively separate it, both originally and after long aging ^ and damage caused by Air leakage problems are caused, and the like.

A group of compositions is now within the scope of the present invention has been found based on silicone emulsions, which has the advantages listed above. These compositions have all the essential properties that are required for a pre-formulated release agent for unvulcanized tires and since they are water-based there are no fire or health hazards or risks associated with their use Associated with pollution problems.

According to the present invention, in its broadest Aspects Compositions for reducing friction between an expanding fluid pressure core and the inner surface of an unvulcanized tire created during vulcanization, the composition being the following Components includes:

a) a high molecular weight polydiorganosiloxane fluid,

b) a high molecular weight alkylene oxide polyol,

c) a particulate solid to create channels to allow air to escape between the expanding pressure core and the unvulcanized tire,

d) water,

e) a thickener and

f) an emulsifying agent,

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the components e) and f) each being present in sufficient quantities are to create a stabilized, non-settling suspension of ingredients a), b) and c) in water.

The compositions are preferably thick and viscous and have a viscosity in the range of 10,000 to 50,000 centipoise at 25 ° C, although ai
can be.

25 c, although higher and lower viscosities are also used

The polydiorganosiloxane liquids or oils of the invention Compositions are known. Generally they are linear polymers of high molecular weight, which are present alone or in the form of concentrated oil-in-water emulsions. In detail they fall under a class of compounds represented by the following formula:

wherein R and R are monovalent hydrocarbon radicals, such as ipathic, halogen-substituted aliphatic and cycloaliphatic radicals _a, for example alkyl, alkenyl, cycloalkyl, halogen-substituted alkyl, including methyl, ethyl, propyl, chlorobutyl. Cyclohexyl, trifluoropropyl, aryl radicals and halogen-substituted aryl radicals, such as phenyl, chlorophenvl, XyIvI, Tolvl and the like, aralkyl radicals such as phenylethyl, benzyl and the like, cyanoalkyl radicals such as cyanoethyl, where R and R can be the same or different, but preferably methyl or methyl and Sthvl or methyl and phenyl; η is a number in a range that corresponds to the fluid

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oily or oily properties of the polymer are compatible at 25 ° C is, the polymer preferably having a viscosity at 25 ° C

in the range of 25 to 100,000 centipoise and R can be the same Rests such as R and R include, as well as hydroxy. Alkoxy, aryloxy and similar radicals.

Exemplary polydiorganosiloxah fluids include the following a: polydimethylsiloxanes, copolymers of dimethylsiloxane and Diphenylsiloxane, terpolymers of dimethylsiloxane, phenylmethylsiloxane and ethylmethylsiloxane, terpolymers of dimethylsiloxane, Methylphenylsiloxane and methyltrifluoropropylsiloxane. Copolymers of dimethylsiloxane and Äthvlmethylsiloxan, Polyäthylmethylsiloxan, Copolymers of dimethylsiloyan and methylorgaathylsiloxane. the Homo- and copolymers can be blocked at the ends, e.g. with triorganosiloxy units, such as trimethylsiloxane-dimethylbenzylsiloxane, Diroethylphenylsiloxane units and the like. Copolymers containing diorganosiloxane can also be used, e.g. from dimethylsiloxane and polyether units. Preferably the organic substituents are selected from methyl and phenyl groups. However, vinyl, trifluoropropyl, Äthvl, Propvl. Octadecvl, allvl cyclohexenyl. Naphthyl, chlormet hvl bromophenyl and the like may be present as substituents.

The liquids are produced by methods that are known and widely used. For example, the appropriate Hydrolyzes diorganodihalosilane (or a mixture of such silanes), a mixture of linear and cyclic prepolymers to manufacture. These or mixtures of the individual linear and cyclic prepolymers are then combined with compounds such as disiloxanes, equilibrated to the triorganosiloxy end groups produce. The lower the concentration of the equilibration compounds, the higher the molecular weight. The liquid is washed with water, neutralized, dried and removed from the

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evaporating constituents freed. Detailed instructions in the "Encyclopedia of Polymer Science and Technology" John Wilev and Sons Verlag, New York, Volume 12, pages 522 ff (1970) included. The Polvdiorganosiloxaη liquids can also available for purchase from a number of manufacturers.

The amount of to be used in the composition of the invention Silicone fluid can vary, but generally will are in the range of 2-20% by weight. If the silicone is added in the form of an emulsion, then this amount is added to the The basis of the silicone solids present in the emulsion is determined ο The silicone liquid preferably makes up 5 - 15% by weight and most preferably about 10% by weight of the composition.

The alkylene oxide polyol can be either a homopolymer of ethylene or propylene glycol or a copolymer of the two. The molecular weight should be high, i.e. at least above 1000. The polyethylene glycols have the general formula

HIGH ₂ (CH ₂ OCH ₂ ) _n CII ₂ OH

HO i-CH ₂ CH ₂ O \ H

where η and χ are numbers large enough to be one molecular weight of at least 1000. The Polypropylene Glyeol have the following: general formula

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CHaCHOH-f ~ _o O CH CH (CH ₀ H OH ₀ CH

J η

HO- ^ -CH (CH ₃ ) CH ₂ O A H

where η and χ have the meaning given above. These polyalkylene glycols are produced by known processes by alkali-catalyzed conversion of ethylene glycol in varying amounts Ethylene oxide and with propylene glycol and propylene oxide. Preferably the alkylene oxide polyol is an ethylene oxide polyol, a propylene oxide polyol or a copolyol of ethylene oxide and propylene oxide. These compounds are available from a number of manufacturers, such as from Olin Corp. under the designation WS-661, from Union Carbide under the designation HV-660, from Jefferson Chemical under the designation WL-850.4, etc.

The amount of polyol in the composition can vary, but there should be at least enough to coexist with the silicone to generate the required lubricity. In general, an amount between 2 and 20% is used, the higher amounts are used with the lower amounts of silicone and vice versa. The amount of polyol is preferably between 7.5 and 15% and particularly preferred is about 10%.

The particulate solid is used to create channels between the sack and the tire to allow the air to escape. It can be anything commonly used for this purpose Material to be used. Mica and talc are particularly suitable. The particle size can vary widely, however

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it is preferably in a range of about 0.09-0.019 mm (corresponding to 160-600 mesh / inch) and a particularly preferred particle size is that of about 0.044 mm (corresponding to 325 mesh / inch).

The amount of particulate solid can vary, but will generally be in the range of 20 to 55 percent by weight. The lesser ones Amounts are used in conjunction with the lower levels of silicone and polyol, i.e. in the more dilute compositions.

The nature of the thickener can vary widely. For example, mineral or inorganic colloids and bentonite * clays can be used, as can organic thickeners such as carboxylated vinyl polymers, for example the Carbopol products from BF Goodrich Co. These thickeners work in such a way that they prevent the particulate constituents from doing so to discontinue. It is therefore sufficient to use it to accomplish this purpose. However, the amount of thickener is generally in the range of 0.05 to 5%, the larger amounts being used when the thickening agent is mineral or inorganic in nature and the smaller amounts being used when it is specially made for the purpose is an organic polymer.

The nature of the emulsifying agent can vary widely, The emulsifying agent can be anionic, cationic or nonionic in nature. The emulsifying agents can be salts of Fatty acids are e.g. ammonium oleate, acetates of fatty acid amines, Monoesters of polyethylene glycols and fatty acids, alkylated aryl polyether alcohols such as acetylphenoxypolyethylene alcohols and similar. Preferably, the emulsifying agent is a sorbitol ester, such as sorbitol hexaoleic acid ester (sorbitan sesquioleate) or an alkyl aryl sulfonate such as sodium dodecyl benzene sulfonate.

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The amount of the emulsifier is selected so that a stable one One-phase mixture of water and the resins is obtained. This amount will generally range from 0.05 to 5 percent by weight. A portion of the emulsifying agent may be present in the silicone when added to the composition as an oil-in-water emulsion is added, the remainder then being added separately.

The manner of mixing the compositions of the invention is common, like that, in a container of suitable size with a stirrer the silicone liquid, some of the water and a

to
Fill a portion of the emulsifying agent / to form an emulsion and then add the thickener. Next, with slow agitation, the particulate material, e.g. mica or talc, and then the alkylene oxide polymer, the remainder of the emulsifier and, if desired, a small amount of a fatty agent such as oleic acid are added. After uniformity in blending, the agitation is increased and maintained until a stable suspension is obtained. As mentioned, the silicone liquid can be added as an emulsion.

The use of the compositions in the tire molding process can take place according to usual methods. For example, they can be placed on the side of the unvulcanized tire with a 36O ° spray nozzle can be sprayed on. The tires are cured according to procedures common in the rubber industry. The description in U.S. Patent No. 2,937,406 is exemplary; in terms of For more detailed information, reference is made to this patent specification.

The invention is explained in more detail using examples of specific approaches that are particularly effective for Have proven to achieve the desired effects.

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example 1

A 1 liter stainless steel beaker equipped with a mechanical stirrer was charged with 114 grams of one An oil-in-water emulsion of a polydimethylsiloxane liquid having a viscosity of 60,000 centipoise at 25 ° C, which has a Silicone content of 34% (available from General Electric Company under the reference SM-2061). Under very slow 22 g of a 0.5% strength thickener (Carbopol 934 the B.F. Goodrich). The thickener was previously dissolved in water and neutralized in water to form a thick gel. After the thickener gel had dissolved in the emulsion, The following ingredients were added with slow stirring: 142 grams of mica with a particle size of about 0.044 mm (325 mesh / inch) to allow air to escape in the mold, 40 g of ethylene oxide-propylene oxide-polyol copolymer (from Olin Chemical Co. under the designation WS 661 or the product of Union Carbide under the name HV 660), 68 g of water, 12 g of sorbitol hexaoleic acid ester as an emulsifying agent and, 2 g of oleic acid (which the Lubrication supported in the form). After blending to uniformity, the stirring speed was increased and held for about half an hour to produce the final composition. The final viscosity was 20,700 centipoise, measured for two minutes on a Brookfield LVT viscometer at 25 ° C, with a No. 3 spindle at three revolutions per minute. The centrifugation stability was in one calibrated 40 ml tube measured for 15 minutes 1000 rpm, rotated. Only 1 ml of the liquid was observed as the top layer.

A sample of the tire compound for the inner liner was coated with a thin film of the composition and

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dries. The coating was allowed to age for 10-15 minutes. To The sample was tested for release properties for 17 days at a temperature of about 21-27 ° C (corresponding to 70-80 ° F). Of the The coefficient of friction of a rubber sliding over it is at the coated sample was only 0.197 compared to 0.9 on an uncoated sample.

Example 2

Into an approximately 19 liters (equivalent to 5 US gallons), polyethylene-lined kettle equipped with a stirrer with variable stirring speeds. About 1270 g (equivalent to 2.8 US pounds) of ethylene oxide propylene oxide polvol copolymer, about 91 g (equivalent to 0.2 US pounds) of oleic acid, about 1320 g (equivalent to 2.9 US pounds) of sorbitol hexaoleic acid ester, about 3640 g (equivalent to 8 US pounds) of an emulsion of high viscosity polydimethylsiloxane fluid (60,000 centipoise at 25 ° C). filled with 34% silicone and about 182 grams (equivalent to 0.4 pounds) of thickener (RTVanderbilt Co., Veegum HV) and enough water to make the final composition 40% by weight. The components are added with slow stirring until the thickener is completely dispersed. About 7540 grams (equivalent to 16.6 US pounds) of mica with a particle size of about 0.09 mm (equivalent to 160 meshes / inch) was then added. The mixture was then stirred at high speed for 2 hours to produce the final composition. Its viscosity was 36,000 centipoise at 25 ° C., measured for 2 minutes
meter, spindle No. 3, 3 rpm.

at 25 ° C., measured for 2 minutes, with a Brookfield LTV viscose

The composition was applied with a very finely dividing sprayer with a 360 ° spray nozzle on the inside of an unvulcanized Vehicle tire applied in an airbag mold before curing. The tire was named after those in the rubber industry

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hardened using the usual method. The lubricant relieves well and reduces air leakage defects better than conventional lubricants .

Example 3

A 2 liter stainless steel beaker equipped with a mechanical stirrer was charged with 394 grams of water and 10 g of mineral colloid with very rapid stirring the thickener was mixed in. until an aqueous gel had formed. After the thickener disperses in the water the following ingredients were mixed with medium stirring speeds mixed in: 40 g of polyethylene oxide-polypropylene oxide-methylsiloxane copolymer (PFA-1200 from General Electric). 110 g of ethylene oxide-propylene oxide-poly oil copolymer, 440 g of talc (901A from Georgia Talc) to allow air to escape in the mold and 0.5 g NaNO- as a corrosion inhibitor. After this one had mixed to a uniform consistency, one high speed stirring became another Maintain half an hour to achieve a uniform composition to ensure. The final viscosity of the product was 29,000 centipoise at 25 ° C as measured on a Brookfield RVF viscometer with a # 4 spindle at 4 rpm for 1 minute. The centrifugation stability was measured in a 40 ml calibrated tube was measured, which was centrifuged at 1000 rpm for 1.5 minutes. There was less than 5 ml of liquid than the top Layer observed.

A sample of tire compound for the inner liner was coated with a thin film of the composition and this film was allowed to air dry. After aging for one day at about 21-27 C (corresponding to 70-RO ⁰ F), the sample was applied to the

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Separation properties investigated. The coefficient of friction of a hardened Rubber that slid over the coated surface was only 0.33 (dynamic friction).

Example 4

329 g of water and 10 g of mineral colloid mw were placed in a 2 liter beaker made of stainless steel, which was provided with a mechanical stirrer. The thickener was mixed with it with very rapid stirring until an aqueous gel had formed. After the thickener was dispersed in the water, the following ingredients were added with a medium agitation speed; 110 g of an oil-in-water emulsion of a polydimethylsiloxane liquid with a viscosity of 60,000 centipoise at 25 ° C and a 3F% silicone content, 112 g of mica with a particle size of about 0.044 mm (corresponding to 325 meshes / inch ) and 330 grams of talc (901A from Georgia Tale) to "allow the air in the mold to escape slowly, further 110 grams of ethylene oxide-propylene oxide poly-oil copolymer and 1 gram of NaNO" for corrosion inhibition after the mixture has become uniform. ^? urde the Rüfargesehwiridigkeit a further half hour maintained, to prepare a uniform composition. the final viscosity of the product was 17,900 centipoise at 25 ⁰ C ₅ screened eat on a Brookfield LVT viscometer using a spindle no. 3 at 3 U / min for The centrifugation stability was measured in a 40 ml calibrated tube with the tube centrifuged at 1000 rpm for 15 minutes 5 ml of liquid observed as the upper layer.

A sample of a rubber mixture for the inner lining was made coated with a thin film of the composition and this film was allowed to air dry. After two days of aging at about

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The sample was released from 21-27 ° C (corresponding to 70-80 ° F) th tested. The coefficient of friction of hardened rubber, that slid over the coated surface was only 0.349 (dynamic friction).

Obviously, in the light of the above teaching, there are others as well Variations in the compositions are possible. In addition to the dimethylsiloxane units, the silicone can, for example, contain diphenylsiloxane units as well as polyether units. A polyethylene oxide polyol can be used in place of the polyol copolymer will. Instead of Carbopol, bentonite, gelled with methanol, can be used as a thickener. Instead of sorbitol hexaoleic acid ester can use sodium dodecylbenzenesulfonate as an emulsifying agent can be used.

The data given above demonstrate that the present invention A pre-formed lubricant for the inside Umralkanisiert tire is created, which is emulsified on Silicones based, non-polluting systems based on water are. It also uses a group of lubricants Created for the inside of tires, tailored to the individual separation and / or air leakage requirements can be. Finally, the compositions according to the invention are effective and easy to use proven.

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Claims (1)

Patent claims t. A composition for reducing the friction between a ^Ky ' expanding fluid pressure core and the inner surface of an uncured tire during vulcanization, characterized by the following ingredients: a) a high molecular weight polydiorganosiloxane fluid, b) a high molecular weight alkylene oxide polyol, c) a particulate solid to create air escape channels between the expanding Pressure core and the unvulcanized tire, d) water, e) a thickener and f) an emulsifying agent, wherein the components e) and f) in a sufficient amount are present to form a stabilized, non-settling suspension of components a), b) and c) in the water, 2. Composition according to claim 1, characterized through in% by weight: a) 2 to 20 polysiloxane. b) 2 to 20 polyol, 4098 83/1206 c) 20 to 55 particulate! Solid, e) 0.05 to 5 thickeners, f) 0.05 to 5 emulsifying agents and
the rest is water. 3. Composition according to claim 1 or 2, characterized
. characterized by having a viscosity in the range of 10,000 to 50,000 centipoise at 25 ° C. 4. Composition according to claims 1-3, characterized in that the polvdiorganosiloxane liquid has a viscosity in the range from 25 to 100,000
Centipoise at 25 ° C. Composition according to Claims 1-4, characterized in that the Polvdiorga nosiloxane liquid has dimethylsiloxane units, dimethylsiloxane
and contains diphenylsiloxane units or polyether units. 6. Composition according to claims 1-5. characterized in that the molecular weight
of the Alkvlenoxvdpolyol is at least 1000. 7. Composition according to claims 1-6, characterized in that dpß dss alkylene oxide polyol 409883/1206 a j ^ hylenoxyd ^ olypl, a propylenoxydpolyol or a Co-Λ of $ thy ^ e: n _; oxy4 · .-. and; Is propylene oxide. ngeh, dien claims 1-7, thereby ge k; e η η ^ e 1 ch η. e, t. . that the particulate. Solid particles, with a size in the range from about 0.0 ^ to about Q, Ojl <* mm (corresponding to WO - 600 Maschea / Zöl !.) 9. Zusamme ns «t; 2iiifi; g to djen Ansprücheti _t 1 -S characterized e- g ke, to: ζ it. i η et. da-ß: dear part herbal solid GZ is immear or talc. Idla. Composition: according to the Angprilchen 1-9. thereby g; eke η n _; z · e £ eh η et, since M the thickening agent is a mineral clloid or a carbojcylated vinyl polymer. %%. The composition of claims 1 -. 10, characterized g _a Eke η η ζ u calibration et that the emulsifying agent a, nxonisch _r ksttioriisch or nonionic ... 12. Composition according to claim 11, d a du r c h ge k e η η ζ e i e h η e t. that the emulsifier one Is sorbitol ester or an alkylarylsulfonate. 13. The composition of claim 12, characterized by it. that the emulsifying agent is sorbitol hexaoleic acid ester. 409883/1206