BRPI1102846A2 - tire nozzle damping process - Google Patents

Abstract

PROCESS FOR MANUFACTURING TIRE WITH FOAM NOISE DAMPER. The present invention is directed to a process for manufacturing a tire having a foam noise damper, comprising the steps of: arranging a silicone rubber foam noise damper on an exposed virgin surface of a green inner liner of a green tire; arranging a barrier layer over the silicone rubber foam noise damper, the silicone rubber foam noise damper being located between the blank surface of the green tire inner liner and the barrier layer; green tire cure; and removing the barrier layer to reveal the silicone rubber foam noise damper.

Description

"PROCESS FOR MANUFACTURING TIRE WITH FOAM NOISE DAMPER"

Relation to Other Patent Applications

This patent application is a continuation-in-part of Serial No. 12/819 535 filed June 21, 2010.

Field of the Invention

This invention relates to a method of protecting a noise damping foam during vulcanization of a tire, wherein the noise damping foam is disposed on the inner lining surface. Definitions

"Carcass" means the tire structure apart from the belt structure, tread, tread, and side rubber on the pads, but including the heels.

"Inner liner" means the layer or layers of elastomer or other material forming the inner surface of a tire and containing the filler fluid within the tire. The "inner lining" of a chamber-type tire is often called a "straightener" to distinguish it from the inner lining of a tubeless tire.

"Pneumatic" means a generally toroidally rolled mechanical device (usually an open torus) having beads and a tread and made of rubber, chemical compounds, fabric and steel or other materials. When mounted on a wheel of a motor vehicle, the tire through its tread provides traction and contains the fluid that sustains the vehicle load.

"Tread" means a molded rubber component which, when attached to a tire casing, includes that portion of the tire that comes into contact with the road when the tire is normally full and under normal load, that is, the footprint.

The terms "cure" and "vulcanize" are intended to be interchangeable terms unless otherwise noted. The terms "raw" and "uncured" are intended to be interchangeable unless

otherwise noted.

"Virgin surface" means a surface, whether cured or not, which has not been cleaned and which has not come into contact with a release agent.

Background of the Invention Government regulations and consumer preferences continue to

compel a reduction in acceptable noise levels produced by passenger car tires. One source of road noise is resonance inside the tube enclosed by the innermost surface of the tire and the rim. One type of effort to reduce tire noise is to muffle the sound of air vibration in the inner tube, whose efforts focused primarily on changing the innermost surface of the tire adjacent to the tire housing. In one approach, foam material is arranged as a noise suppressor in the inner cavity by bonding foam to the inner liner of the pneumatic, which is effective in reducing noise due to tire cavity resonance at 200 to 300. However, the connection of such a noise-suppressing foam to a tire inner liner is problematic.

Raw pneumatic tire housings are constructed as a series of layers of flexible high modulus cords encased in a low modulus rubber. An inner liner is positioned to form the innermost surface of the tire. The raw tire is cured in a curing press using a curing bladder, which forces the tire to expand. During curing, the inner liner expands with the casing, which is forced against the indentations in the curing mold to form the tire tread, and all components are co-cured to provide a substantially cohesive bond between one and the other.

The inner liner for a tubeless pneumatic tire is typically formed from a compound containing a high weight ratio of a halo butyl rubber due to its good barrier properties. Before the tire is cured, the entire inner surface of the inner liner and / or the outer surface of the healing bladder is coated with a release agent. The release agent is commonly referred to as a "liner cement" when used on the inner liner surface, and as a "bladder lubricant" or "bladder spread" when used over the healing bladder. The release arm facilitates removal of the healing bladder from the inner liner after curing so that the inner liner is not damaged. The inner liner (or straightener) for a pneumatic chamber type tire is typically a thin layer of canvas lining stock to protect the nylon direct contact chamber. These interior liners usually do not contain halo butyl rubber as barrier properties are not required.

Thus, prior to attaching a foam noise damper to the cured inner liner, in prior art processes the inner liner must be cleaned to remove contaminants present on the inner liner surface from the molding operation. . In particular, the release agent must be removed from the inner coating surface. Solvents have typically been used for this cleaning operation. Effective solvents for removal of release agents contain hazardous air pollutants. These solvents are thus subject to environmental regulations, which have become stricter in the recent past. Thus it may be desirable to eliminate the need for solvent cleaning of the internal oven surface in order to comply with strict environmental regulations. In addition, solvent cleaning is labor intensive and expensive due to its hazardous nature, so significant cost savings can be realized by eliminating the solvent cleaning process. Alternatively, preparation of the inner liner for application of a foam noise damper may involve scraping the inner liner to provide a suitable surface for adhesion, see, for example, U.S. Patent 7,669,628.

Summary of the Invention

The present invention is directed to a process for manufacturing a tire having a foam noise damper, comprising the steps of: arranging a rubber foam noise damper on a surface

exposed virgin from a raw inner liner of a raw tire;

arranging a barrier layer over the silicone rubber foam noise damper, the silicone rubber foam noise damper being located between the blank surface of the raw tire inner liner and the barrier layer; cure of raw tire; and

barrier layer removal to reveal silicone rubber foam noise damper.

Brief Description of the Drawings

The accompanying drawings, which are incorporated and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention.

Fig. 1 is a sectional view showing an embodiment of the present invention.

Fig. 2 is a non-scaled plan view of an assembly of a barrier layer support large enough for both the entire circumferential surface of an inner-facing foil and the entire circumferential surface of a damper. of foam noise, and to provide a pull tab.

Fig. 3 is a perspective view schematically illustrating positioning of a prepared inner liner, barrier layer and foam noise damper (as shown in Fig. 2) on a tire mounting drum.

Fig. 4 is a non-scaled plan view of a peeled barrier layer support assembly of the inner liner to reveal the foam noise damper of a cured tire.

Fig. 5 is a partial cross section of a cured tire after removal of a barrier layer (as shown in Fig. 4) having a foam noise damper adhered to the inner liner surface.

Detailed Description According to the present invention, a foam noise damper adhered to the inner liner of a raw tire is protected from mold release agent contamination and the aggressive pressure and temperature of the curing process by overlapping a protective barrier layer over the foam noise damper and adhering the protective barrier to the raw virgin inner lining surface. In one embodiment, the protective barrier layer is a thermoformed film adapted to stretch with the tire materials during the forming and curing process. In one embodiment, the protective barrier layer is a thin rubber sheet. In one embodiment, the barrier layer is coated is coated with a pressure sensitive adhesive (PSA) which is pressed to the raw virgin inner lining surface to reliably and reliably adhere to the thermoformed film. The optional PSA is particularly effective in preventing barrier layer movement during high-pressure lining cement spraying onto the inner liner. The invention may still be understood by reference to the Figures.

Similar reference numerals are used by all of the various figures to refer to similar components, and similar reference numerals are used to refer to components in both cured and uncured (raw) states.

Fig. 1 shows a cross section of an uncured, or "raw" tire assembly 10 after tire construction according to the present invention. Raw tire assembly 10 includes a housing 12 having a tread 13 disposed on the outermost surface, where tread 13 is the portion of the tire assembly 10 that contacts the ground during operation of a cured tire. During curing, grooves 115 shown in dashed lines are printed on the tread by a mold. As is known in the art, the housing 12 may include one or more strings and the housing surrounds the bead portions 14 of the raw tire 10. An inner liner 16 is disposed within the housing 12 to face the inner tube 24. A compressed foam noise damper 22 is disposed on the radially inwardly virgin raw surface 28 of the inner liner 16. In accordance with the present invention, the foam noise damper 22 is compressed and protected with a removable barrier layer. 20 adhered to raw virgin surface 28 of inner liner 16. As will be described herein, after curing of the raw tire 10, barrier layer 20 is removed from foam noise damper 22 and inner liner 16 to allow damper relaxation. foam noise 22 and by what to expand to its full volume.

Forming the tire assembly 10 involves mounting the inner liner 16 in a raw state, i.e. an uncured state adjacent the raw tire housing 12, positioning the foam noise damper 22 over the virgin surface. 28 of inner liner 16, and lining barrier layer 20 over and thereby compressing compressed foam noise damper 22 and adhering edges 27 of barrier layer 20 to raw virgin surface 28 of raw liner 16. A raw tread 13 is mounted adjacent to the outer surface of the tire casing 12. This raw tread assembly 10 is then placed in a cure mold (not shown) so that the tread support 13 is positioned against the mold surface (not shown), and the barrier layer 20 is further from the mold surface to form the innermost layer, with the foam noise damper positioned between the inner liner 16 and the barrier layer 20.

Typically, before all components are in place within the mold, a release agent (not shown) is applied to the raw inner liner 16 and over the barrier layer 20. The release agent, which is also referred to as lining cement, It is generally applied through a high pressure spread. Examples of liner cement-type release agents include polysiloxane or silicon based organo materials such as pulverized mica polydimethyl siloxane or crystalline silica. In one embodiment, a pressure sensitive adhesive (not shown) is applied between the barrier layer 20 and the uncoated raw virgin surface 28 so that the high pressure lining cement spread does not displace the barrier layer 20 and the foam noise damper 22.

After the raw mount 10 with shielded foam noise damper is placed in the mold, an expandable curing bladder (not shown) is then expanded against the inner liner 16 and barrier layer 20 to press the raw tire assembly onto the mold surface to pressing the raw tread support 13 into a tread pattern formed on the mold surface. A vulcanization temperature is applied to the mold while the tire assembly 10 is pressured from the expanded cure bladder long enough to cure the tire assembly 10. Barrier layer 20 protects the damper from foam noise Compressed air from mold release agent and pressure environment contamination and aggressive temperature of the pneumatic mold during curing of the raw tire 10. After curing is completed, the curing bladder is emptied and separated from the inner liner 16 and the bed. - from barrier 20.

An embodiment of a process of the present invention may be further described with

reference to Figs. 2-3. As illustrated in Fig. 2, before the inner liner 16 is positioned on a construction drum 32, a foam noise damper 22 is symmetrically positioned around the longitudinal center axis of the raw inner liner 16. A barrier layer 20, having a width greater than the width of the foam noise damper 22 but less than that of the raw inner shell 16, is symmetrically positioned around the longitudinal central axis of the raw inner shell 16 so that the noise damper of foam 16 is between raw inner liner 16 and barrier layer 20. Barrier layer edges 27 are pressed to raw virgin surface 28 of raw inner liner 16 making barrier layer 20 reliable and removably adhered. At the same time, the foam noise damper 22 is compressed from its fully expanded state to a state compressed by the barrier layer 20. In one embodiment, there is a half turn or "overlap" 30 sufficient to yield a pull tab to facilitate easy removal of the barrier layer 20 after curing. Alternatively, no overlap is included.

As shown in Fig. 3, from about 2 cm to 20 cm from one end of the barrier layer 20 extends beyond one end of the raw inner liner 16 when it is positioned over the drum 32 to form the overlap 30. To facilitate visual detection after curing, the overlay 30 may be colored to contrast with the black of the inner liner 16.

The raw tire assembly 10 is removed from the drum 32 and can be stored with the barrier layer 20 protecting the muffler from foam noise 22. The innermost surface 26 is then sprinkled with lining cement, which completely or partially covers the barrier layer 20, and the raw assembly 10 is placed in a curing press to be conventionally cured. Fig. 4 shows a cured tire assembly 110 after removal of a curing press. After the cured tire assembly 110 is removed from the press, the interior of the tire may be vacuumed to remove liner cement, which is generally loosely bonded to the barrier layer 20. As seen in Fig. 4, the barrier layer 120 is , then manually removed in one piece by pulling, for example, over the protruding edge 130 of barrier layer 120. The foam noise damper 122 is exposed, and is free of lining cement. Upon removal of the barrier layer 120, the foam noise damper 122 relaxes and expands to its full volume.

Application of noise damper 22 to drum 32 may cause excessive stress on the foam leading to undesirable shear in the foam. To avoid foam shearing on the drum 32, at least one slot or tooth may be made in the transverse section of the foam noise damper perpendicular to the circumferential direction of the drum. One or more slits or teeth may be made to a depth of foam sufficient to prevent shear by applying foam noise damper 22 to drum 32.

Application of the barrier layer 20 as illustrated in Figs. 2 and 3 is usable in the case of a barrier layer made of a material which will stretch and survive the stress applied during the tire construction process. In the case of a barrier layer manufactured from a material which is not sufficiently stretched to survive the tire construction process, prior to application of the barrier layer during the tire construction process, the barrier layer 20 may instead be applied over foam noise dampener 22 and to the virgin raw surface of the inner liner of an uncured raw tire but completed after the tire construction process. Foam noise damper 22 may likewise be applied during the tire building process, or later to the raw tire as desired and depending on the foam's ability to stretch and withstand the stress of the construction process. Tire Such a raw tire having the barrier layer applied after the tire building process can then be cured into a tire mold, with the inner lining surface protected as described hereinbefore. In one embodiment, the barrier layer is a thermoformable film. In order to

pandering with the inner liner during construction and curing of raw tire, the thermoformed film should exhibit the sticking property, which refers to the ability of a material to stretch without returning to its original shape. The film advantageously exhibits sticking in at least one direction, and preferably in both directions, commonly referred to as machine direction (MD) and cross direction (CD). Sticking force, according to room temperature testing at a crosshead speed of 50.8 cm / min, is advantageously below about 25 lbf, and most advantageously below about 20 Ibf, at least least one direction, and preferably in both directions, for a 2.54 cm wide support. Non-oriented films are desirable, although partially oriented films may also be used. Non-oriented films can be characterized by essentially equal sticking forces in both machine and cross directions.

In addition, the thermoformable film should exhibit a melting point greater than the tire assembly cure temperature, which is generally in the range of about 1210C (250 ° F) to about 200 ° C (392 ° F). The thermoformable film must still have sufficient strength to be removed from the inner liner in one piece for ease of manufacture. In an exemplary embodiment, the thermoformable film may be overlapped to form a pull tab to facilitate removal of the film, and the overlapping portion of the film should not fuse together. In one embodiment, the thermoformable film has a thickness of less than about 127 micrometers, for example, less than about 76.2 micrometers. In another embodiment, the thermoformable film has a thickness greater than about 15 micrometers, for example, greater than 19 micrometers. Nylon 6 and nylon 6,6 films of the order of 19 micrometres to 50.8 micrometres thick can serve as exemplary thermoform films in the present invention. Exemplary films include: CAPRAN nylon, which is a commercially available multipurpose nylon 6 film from Honeywell, International, Pottsville, Pennsylvania; fluorinated ethylene propylene (FEP) films, such as DuPont Films FEP TEFLON carbide fluoride film or A4000 from Airtech International, Inc .; 1-phenyl-3-methyl-5-pyrazolone (PMP) films, such as Honeywell's PMP Release Film; and C917 DARTEK, which is a 6.6 nylon film available from Exopack Canada. Sticking strength, maximum tensile strength,% elongation and thickness for these exemplary films (2.54 centimeters wide) are provided below in Table 1. Exemplary thermoform 'films are those which are non-oriented or only partially oriented. and requires a sticking force in both machine and transverse directions of less than 20 Ibf. Table 1

Sample Thousand Mm Traction Sticking- Elonga- Max (MPa) tion (Ibf) tion (%) TEFLON® FEP (MD) 1 25.4 22 2.25 393 TEFLON® FEP (CD) 1 25.4 23.5 2.6 272 PMP (MD) 1 25.4 28 3.5 107 PMP (CD) 1 25.4 28 2.5 90 C917 DARTEK®, (MD) 2.0 50.8 173 11.5 202 C917 DARTEK®, (CD) 2.0 50.8 118 11.25 128 C917 DARTEK®, (MD) 0.75 19 48.9 4.5 90 C917 DARTEK®, (CD) 0.75 19 47.7 4.25 59 CAPRAN® Nylon (MD) 1 25.4 61 7 118 CAPRAN® Nylon (GD) 1 25.4 63 6 60

By way of example, nylon films are particularly useful in the process of the present invention. Examples of film-forming nylon are linear polycondensates of 6 to 12 carbon atoms and conventional polycondensates of diacams and dicarboxylic acids, for example, nylon 6,6; nylon 6.8; nylon 6.9; nylon 6.10; nylon 6.12; nylon 8.8; and nylon 12.12. Still examples to be mentioned are nylon 6, nylon 11, and nylon 12, which are manufactured from the corresponding lactams. In addition, polycondensates of aromatic dicarboxylic acids, for example isophthalic acid or terephthalic acid, with diamines, may be used. hexamethylene diamine, or octa methylene diamine, polycarbonates of aliphatic starting materials, for example m- and p-xylylene diamines, with adipic acid, suberic acid, and sebacic acid, and polycondensates based on alicyclic starting materials, for example cyclohexane dicarboxylic acid, cyclohexane diacetic acid, 4,4'-diamino dicyclohexyl methane and 4,4'-diamino dicyclohexyl propane.

In one embodiment, the barrier layer is a removable internal rubber backing.

grip, adhered to the inner lining of the tire.

In this embodiment, the barrier layer as a removable rubber backing is comprised of a rubber mixture of (A) from about 50 to about 100, preferably about 60 to about 90 parts by weight of butyl rubber. and correspondingly (B) about 50 to about 0, preferably about 40 to about 10, parts by weight of an unconjugated ethylene / propylene / diene terpolymer rubber.

It is understood that the rubber support may also contain conventional rubber composition ingredients including processing oil, accelerators, conventional sulfur curing agents, pigments, carbon black, zinc oxide, stearic acid, stickiness resin , and plasticizer.

In the practice of this invention, said rubber support is required to be co-vulcanized with the tire in the sense that the uncured rubber support is constructed on the inner liner as a part of the raw tire construction, or not. - cured. Thus, in the molding and curing operation for tire production, the support and raw tire cure substantially simultaneously.

In one embodiment, the co-cured rubber strip barrier layer has a relatively low adhesion to the inner surface of the tire of less than about 1.8 kg / cm linear, so that it can be conveniently pulled either manually or with and a tackiness value in the range of about 10 to about 30 Newtons so that it will properly adhere to or stick to the inner surface of the raw tire.

The adherent, removable rubber support typically has a thickness in the range of from about 0.025 to about 0.25, preferably about 0.05 to about 0.2 centimeters. After the tire containing the rubber support over its inner lining has been shaped and cured, the co-cured rubber support as the barrier layer can simply be removed manually or by hand or automatic device. The rubber sheet can be color coded with a pigment to contrast with the color of the tire itself so that it can be easily seen if it was actually removed before further processing of the tire. Butyl rubber for the rubber support is generally of the type prepared

polymerization of a mixture of isobutylene and isoprene, with the largest portion being isobutylene. Butyl rubber typically has an average molecular weight in excess of 200,000, preferably in the range from about 200,000 to about 600,000 and even more preferably in the range from about 200,000 to about 400,000. The rubber tire itself vulcanized can be of various curable rubbers.

sulfur fuels such as natural rubber and synthetic rubber and mixtures or combinations thereof. For example, it may be at least one of rubber-like butadiene / styrene copolymer, butadiene / acrylonitrile copolymer, cis-1,4-polyisoprene (natural or synthetic), polybutadiene, isoprene / butadiene copolymer, butyl rubber, rubber halogenated butyl, such as chlorine or bromine butyl rubber, ethylene / propylene copolymer or ethylene / propylene terpolymer (EPDM). Typically the various polymers are cured or vulcanized by standard sulfur curing processes and recipes. In particular, while other portions of the tire may be of such rubbers, the blank inner surface of the tire to which the rubber support is co-vulcanized is typically and preferably comprised of a butyl rubber, natural rubber, or a mixture thereof. Such butyl rubber may conveniently be selected from at least one butyl rubber or a halo butyl rubber such as chloro butyl or bromo butyl rubber.

The vulcanized rubber tire itself may be of various sulfur-curable rubbers such as natural rubber and synthetic rubber and mixtures or combinations thereof. For example, it may be at least one of rubber-like butadiene / styrene copolymer, butadiene / acrylonitrile copolymer, cis-1,4 polyisoprene (natural or synthetic), polybutadiene, isoprene / butadiene copolymer, butyl rubber, butyl rubber halogenated, such as chlorine or bromine butyl rubber, ethylene / propylene copolymer or ethylene / propylene terpolymer (EPDM). Typically the various polymers are cured or vulcanized by standard sulfur curing processes and recipes. An exemplary recipe for the rubber support used as a barrier layer.

The rubber support for this example may be prepared according to the following recipe in which the ingredients of Table 2a are mixed in a Banbury mixer and the resulting mixture mixed in a mill with the ingredients.

from Table 2b. Table 2a

Compound Parts

Butyl Rubber 70.0

EPDM1 30

Carbon black (ETF) 50

Stearic acid 1.5

Zinc Oxide 2.0

Sticky resin2 8.0

1 ethylene / propylene / diene rubber obtained as Nordel 1320, Nordel being a registered trademark of DuPont de Nemours, E.l. Co. 2 diolefin copolymer-type hydrocarbon-derived stickiness resin /

olefin having a softening point in the range of about 94 ° C to about 98 ° C.

Table 2b

Compound Parts

Mercaptobenzothiazole 1.0

Tetra methyl thiouram disulfide 1.25

Sulfur 2.0

In one embodiment, it may be desirable to include a tackifier in the recipe for the rubber composite support as a construction aid during the construction of the raw tire itself. In this regard, generally about 2 to about 10 parts by weight of stickiness forming resin for said butyl and EPDM rubbers are used. Suitable tackifiers include terpene resins and synthetic hydrocarbon derived resins having a softening point in the range of about 50 ° to about 1100 ° C.

For example, such resins may be prepared by polymerizing hydrocarbon monomers in the presence of the catalyst such as aluminum chloride or boron trifluoride or boron etherate trifluoride. Such monomers, for example, may be a mixture of diolefin and mono olefin hydrocarbons containing 4-6 carbon atoms. For example, piperylene may be copolymerized with methyl branched alphaolefin containing 5-6 carbon atoms.

The optional PSA (Pressure Sensitive Adhesive) is a rubber based adhesive that is compatible with the inner liner rubber. As is known in the art, PSAs typically comprise primarily a polymer system, one or more tackifiers, and one or more plasticizers. In the present invention, the polymer system for PSA is rubber-based to be compatible with the inner liner rubber. Without being bound by theory, during tire assembly curing, the PSA is believed to lose its status as a PSA due to migration of the stickiness former and / or other materials and / or degradation of the PSA at high temperature. When the thermosetting film is removed, all or any of the previous PSA, or PSA, may be removed with the film and / or any or all of it may remain on or as part of the inner liner. Again, without being bound by theory, if the PSA composition is based on a rubber that is compatible with the inner liner rubber, then during curing, the degrading PSA may, in whole or in part, migrate to the inner liner surface. , thus becoming part of the cured virgin inner lining surface. Alternatively, it may leave a cohesively bonded surface coating, but this coating is itself an inner liner-type rubber and is free of release agent, thus being essentially the same as the cured virgin inner liner surface. Thus, in one exemplary embodiment, the PSA is curable during tire vulcanization to cohesively bond with or become a part of the inner tire lining.

In one embodiment, the PSA may be a natural rubber based butyl rubber based adhesive, halo butyl rubber based or polybutadiene rubber based adhesive or combinations thereof as these rubbers are commonly used tire materials . By "rubber based" is meant that rubber is the main component of PSA, that is, the component present in the largest amount. Still in an exemplary embodiment, the PSA is a permanent grade hot melt PSA. An exemplary PSA is commercially available from H.B. Fuller Company, Vadnais Heights, MN1 as a permanent grade hot melt PSA under product number HL2201X. Another PSA is 3M (formerly Emtech) product number G1110. The PSA reliably adheres the thermoformable film to the inner lining surface, and even allows the thermosetting film to be removed from it after tire assembly curing.

PSA may be coated onto the hot-melt film by any desirable process, such as solvent coating or hot melt extrusion coating. A film can also be purchased pre-coated. The PSA coated film may be adhered by any pressure suitable for the particular type of adhesive. For example, hand pressure can be used to adhere the PSA to the internal oven, or a roll such as a 2.54 cm roll can be rolled along the surface of the PSA coated film to adhere the PSA.

A cured tire 110 having the barrier film removed is shown in Fig. 5. In Fig. 5, tire 110 is shown with tread 113, tread grooves 113 provided to tread 113 during curing, housing 112, lugs 114, and inner lining 116. The foam noise damper 122 is fixed within the inner lining 116 radially into the tread 113 as shown in Fig. 5. Similarly, to easily deform during running and Not affecting running performance such as steering stability, the damper material is preferably a low density, light weight flexible material, for example foamed rubber, foamed synthetic resins, cellular plastics and the like. In the case of foamed materials (or sponge materials), an open cell type and a closed cell type may be used, but an open cell type is preferred. For example, synthetic resin foams such as ether based polyurethane foam, ester based polyurethane foam, polyethylene foam and the like; Rubber foams such as chloroprene rubber foam, ethylene - propylene rubber foam, nitrile rubber foam, silicone rubber foam and the like may be used. In particular, suitable foams must be able to withstand the high temperature and pressure environment present during the tire molding process. In one embodiment, an open cell type foam material, more specifically, polyurethane foam is used.

In one embodiment, a silicone rubber foam is used. In one embodiment, the silicone rubber foam has a specific weight ranging from 0.01 to 0.4. In one embodiment, the silicone rubber foam has a specific weight ranging from 0.015 to 0.3. In one embodiment, the silicone rubber foam has a specific weight ranging from 0.025 to 0.25. Suitable silicone rubber is Magnifoam MF1-6535 having a density of 104.2 g / cm3 (6.5 lb / ft3) (specific weight 0.1).

In carrying out using silicone rubber foam, to ensure adhesion of the silicone rubber foam to the inner lining an adhesive is required. The adhesive is applied to the inner liner prior to application of the silicone rubber foam. In one embodiment, the adhesive is an acrylic adhesive. Suitable acrylic adhesive is commercially available as 3M 6038 adhesive transfer tape.

Depending on the environment where the tire is used, there is a possibility of

that the air filling the tire cavity to inflate the tire is damp and water provides condensation in the closed cavity. Likewise, foam materials that are difficult to hydrolyze such as ester based polyurethane are suitably used. Also, in order to prevent water penetration into the noise damper, a

Such water repellent may preferably be made on the foam material. Also, a mildew proof treatment may preferably be done.

In addition, in order to avoid poison in the emission gas generated when burning tire waste, it is preferred that raw materials not including halogen be used to manufacture the foam material.

By disposing a certain volume of foam material in the tire cavity, donate resonances in the tire cavity can be controlled and vibrations of the tread portion are reduced. Therefore, noise generated from the tire during running can be reduced. In particular, noise reduction due to tire cavity resonance measured at a frequency of 200 to 300 Hz is desirable.

The foam noise damper has a specific weight and size suitable for noise level reduction due to tire cavity resonance at 200 to 300 Hz. In one embodiment, the foam has a higher specific weight in a range of 5 to 60 kg / m3. In one embodiment, the foam noise damper has a radial tire thickness ranging from 10 to 50 mm. In one embodiment, the foam noise damper has a width in the axial direction of the tire ranging from 30 to 150 mm. In one embodiment the foam noise damper is arranged circumferentially around the tire.

The foam noise damper 22 is fixed to the inner lining radially within the tread, and is adhesively secured to the inner lining raw rubber 16. With tire curing, the foam noise damper 22 and the cured rubber of the inner liner 16 are adhesively bonded. Alternatively, the foam noise damper 122 may be attached using an adhesive applied directly to the foam or as double-sided adhesive tape. With respect to the adhesive, in one embodiment an adhesive tape having a base tape

with a coating or layer of an adhesive material on one side and a coating or layer of an adhesive material on the other side may be used. In one embodiment, an adhesive tape having no backing tape and consisting of only double layers of different adhesive materials may be used. In one embodiment, an adhesive consisting of only a single layer of an adhesive material may be used.

In the case of tape, the base tape may be, for example: plastic film such as polyester; plastic foam sheet such as acrylic foam; bonded material or nonwoven fabric; a textile fabric; and the like.

With respect to the adhesive material, for example, a rubber based adhesive comprising natural rubber and / or synthetic rubber and additives, for example tackiness, fabric softener, aging resistor and the like; an acrylic pressure sensitive adhesive comprising a plurality of acrylic ester copolymers and a polyfunctional monomer having different glass transition temperatures (containing high heat resistance type, flame resistant type and adhesion type pressure sensitive adhesives). at low temperature); a silicone pressure sensitive adhesive comprising a silicone rubber and a resin; a polyether adhesive; a polyurethane adhesive and the like may be suitably used.

The use of a thermosetting adhesive comprising a thermosetting resin, for example epoxy resin or the like is not preferred in view of production efficiency because the additive needs to be heated to about 130 ° C for about 30 minutes.

For adhesive materials, it is possible to use the same adhesive material, but it may be desirable to use different types of adhesive materials. For example, a rubber adhesive strongly adhering to the tire rubber, and an acrylic pressure sensitive adhesive strongly adhering to the noise damper are used on or adjacent the respective sides of an adhesive tape.

The invention is further illustrated by the following non-limiting examples. Example 1

In this example, the curing effect of a polyurethane foam bonded to an inner lining compound is illustrated.

A polyurethane foam support (specific weight 0.03 - 0.05 g / cm3) was applied to a sheet of raw inner lining compound to form a layered structure. The layered structure was then cured for 23 minutes at 150 ° C under 7.03 kgf / cm2 in a bladder mold. Inspection of the cured layered structure upon pressure release showed that the foam was smoothed and does not regain its original shape.

Example 2

In this example, the curing effect of a silicone rubber foam bonded to an inner coating compound is illustrated.

A silicone rubber foam backing (MF1-6535, density 0.1 g / cm3 from Roger Corporation) was applied to a sheet of raw inner lining compound to form a layered structure. The layered structure was then cured for 23 minutes at 150 ° C under 7.03 kgf / cm2 pressure in a bladder mold. Inspection of the cured layered structure upon pressure release showed that the foam had recovered its original shape but was not sticking to the rubber lining compound. * 5 Example 3

In this example, the curing effect of a silicone rubber foam bonded to the inner liner of a raw tire is illustrated.

A silicone rubber foam backing (MF1-6535, density 6.5 Ib / ft3, by Roger Corporation, with 3M double-sided acrylate adhesive, 3M-3068) was attached to the inner liner in the crown area of a raw tire. entirely built. Silicone mold release sparge was applied and the tire was then cured in a tire mold at 169 ° C for 14 minutes under a pressure of 18.28 kgf / cm2. With mold release, the foam recovered its original shape but was wet to the touch due to the mold release agent. Example 4

In this example, the curing effect of a protected silicone rubber foam bonded to the inner liner of a raw tire is illustrated.

A silicone rubber foam backing (MF1-6535, density 6.5 Ib / ft3, from Roger Corporation with 3M double-sided acrylate adhesive, 3M-3068) was bonded to the inner lining in the crown area of a fully raw tire. built. The foam was covered with 2 mil thick 6.6 Dartek C917 nylon film; The film was wide enough to cover the foam and to bond the edges of the film to the inner coating surface. Silicone mold release clearance was applied and the tire was then cured in a tire mold at 169 ° C for 14 minutes under 18.28 kgf / cm2 pressure. With mold release, the film was removed exposing the foam. The foam recovered its original form and was free of release agent.

As seen from the results of Examples 1 through 4, a silicone rubber foam noise damper applied to a raw support is able to recover its original shape and therefore survives the temperature and pressure conditions experienced by a raw tire during cure when its melting temperature (204 ° C) is above curing conditions. In contrast, a polyurethane foam noise dampener has remained flattened when its melting temperature is below curing conditions and therefore does not survive these conditions. This is significant because in order to be an effective noise damper, the foam noise damper must be fully expanded in its fully foamed condition.

Use of the barrier film further protected the silicone rubber foam from the effects of silicone release spreading. Although the present invention has been illustrated by describing one or more embodiments thereof, and although the embodiments have been described in considerable detail, they are not intended to restrict or in any way limit the scope of the claims set forth to such details. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broadest aspects is therefore not limited to the specific details, representative apparatus and process and illustrative examples shown and described. Likewise, they can be made of such details without departing from the scope of the generic inventive concept.

Claims (10)

A process for making a tire having a foam noise damper, characterized in that it comprises the steps of: arranging a silicone rubber foam noise damper on an exposed virgin surface of a raw inner liner of a raw tire; arranging a barrier layer over the silicone rubber foam noise damper, the silicone rubber foam noise damper being located between the blank surface of the raw tire inner liner and the barrier layer; vulcanization of the raw tire; and removing the barrier layer to reveal the silicone rubber foam noise damper. Process according to Claim 1, characterized in that it comprises the step of: applying an adhesive to the exposed virgin surface prior to arranging the silicone rubber foam noise damper over the exposed virgin surface, where The adhesive is between the silicone rubber foam noise damper and the blank surface. Process according to Claim 1, characterized in that it further comprises the step of attaching at least one edge of the barrier layer to the virgin surface of the inner covering of raw tire. Process according to Claim 1, characterized in that the barrier layer is a thermoformable film. Process according to Claim 1, characterized in that the barrier layer is a nylon film. Process according to Claim 1, characterized in that the barrier layer is a rubber backing. Process according to claim 1, characterized in that the barrier layer is a rubber support comprising butyl rubber and ethylene propylene diene rubber (EPDM). Process according to claim 1, characterized in that the barrier layer is a rubber backing, and the rubber backing is co-vulcanized with the raw inner lining. Process according to Claim 1, characterized in that the silicone rubber foam noise damper has a specific weight ranging from 0.01 to 0.4. A process according to claim 1, characterized in that the silicone rubber foam noise damper has a specific weight ranging from 0.015 to 0.3.