CA2095504A1 - Mineral filled epdm/epr compositions for white sidewall compounds - Google Patents
Mineral filled epdm/epr compositions for white sidewall compoundsInfo
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- CA2095504A1 CA2095504A1 CA 2095504 CA2095504A CA2095504A1 CA 2095504 A1 CA2095504 A1 CA 2095504A1 CA 2095504 CA2095504 CA 2095504 CA 2095504 A CA2095504 A CA 2095504A CA 2095504 A1 CA2095504 A1 CA 2095504A1
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Abstract
ABSTRACT OF THE DISCLOSURE
A mineral-filled white sidewall compound (25) prepared from a thermoplastic polymeric composition of matter comprises (A) 100 parts by weight of a polymer blend comprising (1) from at least about 10 to 95 parts by weight of polyolefins having from about 0.5 to about 13 percent by weight crystallinity, the polyolefins being prepared from monomers having at least 2 carbon atoms and mixtures thereof; and (2) from about 5 to 90 parts by weight of a thermoplastic crystallinity enhancing polymeric additive;
(B) from about 20 to 200 parts by weight of a filler selected from the group consisting of reinforcing and non-reinforcing fillers and mixtures thereof per 100 parts of the polymer blend; and (C) from about 20 to 150 parts by weight of a processing material and mixtures thereof, per 100 parts of the polymer blend; the white sidewall compound being adherable to a conventional cured tire black sidewall (21) without the use of solvents or water-based adhesives. A method for applying a mineral-filled thermoplastic white sidewall compound to conventionally cured tire black sidewalls comprises the steps of providing a tire (10) at least partially cured and having a black sidewall (21);
applying a mineral-filled thermoplastic white sidewall compound to the tire black sidewall to form a white sidewall (25); and bonding the white sidewall to the tire sidewall under sufficient pressure and heat to provide acceptable adhesion without the use of a solvent or a water based adhesive. The present invention also provides a tire (10) having a circumferentially grooved black sidewall area (21) and a mineral-filled white sidewall compound (25) adhered thereto.
9201013 FIR.P.US0068
A mineral-filled white sidewall compound (25) prepared from a thermoplastic polymeric composition of matter comprises (A) 100 parts by weight of a polymer blend comprising (1) from at least about 10 to 95 parts by weight of polyolefins having from about 0.5 to about 13 percent by weight crystallinity, the polyolefins being prepared from monomers having at least 2 carbon atoms and mixtures thereof; and (2) from about 5 to 90 parts by weight of a thermoplastic crystallinity enhancing polymeric additive;
(B) from about 20 to 200 parts by weight of a filler selected from the group consisting of reinforcing and non-reinforcing fillers and mixtures thereof per 100 parts of the polymer blend; and (C) from about 20 to 150 parts by weight of a processing material and mixtures thereof, per 100 parts of the polymer blend; the white sidewall compound being adherable to a conventional cured tire black sidewall (21) without the use of solvents or water-based adhesives. A method for applying a mineral-filled thermoplastic white sidewall compound to conventionally cured tire black sidewalls comprises the steps of providing a tire (10) at least partially cured and having a black sidewall (21);
applying a mineral-filled thermoplastic white sidewall compound to the tire black sidewall to form a white sidewall (25); and bonding the white sidewall to the tire sidewall under sufficient pressure and heat to provide acceptable adhesion without the use of a solvent or a water based adhesive. The present invention also provides a tire (10) having a circumferentially grooved black sidewall area (21) and a mineral-filled white sidewall compound (25) adhered thereto.
9201013 FIR.P.US0068
Description
2093~0~
M~EI~AL FILLED EPDM/lEPR COMPOSlTIONS FOR
VVlIlTE SIDEWALL TII~E COMPOUNDS
S TEOEIN~CAL FIELD
The present invention relates generally to compositions for white sidewall tire compounds. The white sidewall tire compounds comprise a blend of ethylene-propylene-diene terpolymer, referred to herein as EPDM, ethylene-propylene copolymer, referred to herein as EPR, or other similar olefin type polymers or blends 10 thereof with a crystallinity enhancing thermoplastic polymeric additive such as a homopolymer of polyethylene or polypropylene as well as copolymers of ethylene/octene and ethylenelbutene or the like. More particularly the compounds contain non-black mineral fillers as replacements for carbon black. Oftentimes, a stain barrier skim (some 20 to 30 mils in thickness) is inserted at the interface of the black sidewall and white 15 sidewall compounds in order to prevent staining materials such as oils and antioxidants (i.e., p-phenylenediamines) from migrating into the white sidewall compound. Thewhite sidewall compound is adhered directly to the stain barrier skim (optional) or black sidewall of a solid or pneumatic tire using heat and some pressure and without solvents or water based adhesives. Moreover, a thin thermoplastic film can be provided between 20 the white sidewall compound and the stain barrier skim or black sidewall to improve adhesion therebetween.
.
BACKGROllND OF THE ~VENTION
Tires having white or decorative sidewalls are conventionally made by 25 building the white sidewall in place, applying a thin black cover strip thereover and curing the tire. The purpose of the cover strip is to protect the white sidewall during handling and curing so that it does not become discolored by contact with staining black components of the tire or mold residue materials. After the tire has been cured and cooled, the cover strip is buffed away, exposing the white sidewall. Nevertheless, the 30 white sidewall is relatively soft and can be subsequently blemished, marked or scuffed during shipment with other tires and general handling until it is installed onto a vehicle and thereafter.
9201013 FIR.P.US0068 2~95~0~1 Thus, the art has recognized a need for a white sidewall compound that has improved deformation resistance and durability over conventional compounds as well as a white sidewall that can be applied to a tire subsequent to cure, thereby obviating the need for the cover strip and subsequent removal operations. Also, the white 5 sidewall composition can be applied to a cured tire without the use of an adhesion system. An example of an uncured applique being co-cured with a green tire is described in U.S. Pat. No. 5,058,647 and an example of an uncured applique applied to a cured tire is described in U.S. Pat. No. 5,049,220. However, neither patentteaches the use of a tougher EPDM/EPR-based compound.
10Various EPDM compounds having high crystallinity are known but not the use thereof in white sidewalls. U.S. Patent No. 5,086,121, for instance, is directed toward a thermoplastic olefin composition. In this composition, there is provided a polyolefin component, such as high density polyethylene and two rubber components, only one of which is cured by a cure package. For example, the two rubbers employed 15 may include a halogenated butyl rubber and EPDM. A certain cure package, such as a zinc oxide system, is added so that only the halogenated butyl rubber is cured. The second rubber component remains uncured. A preferred EPDM is a highly crystalline terpolymer. Therefore, this pater~t discloses an uncured EPDM in the presence of a polyolefin such as a high density polyethylene. It is further noted that such a 20 composition provides improved physical properties, such as improved tensile strength and the like.
U.S. Patent No. 4,036,912 discloses a thermoplastic polymer blend of, for :-example, EPDM polymer with crystalline polypropylene. The blends achieve higher tensile strength and high structural integrity. No curing or cross linking agents are used 25 to obtain these characteristics. The polymers are mixed in a range of from about 5 parts by weight to about 200 parts by weight of polypropylene for every 100 parts by weight of EPDM.
.U.S. Patent No. 3,941,859 discloses a highly crystalline EPDM polymer blended with a polyolefin to form a blend having superior tensile strength. No cure .~
9201013 FIR.P.US0068 209a~0~
package is employed. Similarly, U.S. Patent No. 3,919,358 also discloses a crystalline EPDM blended with a polyolefin.
SUMl\/IARY OF THE I~VENTION
5It is therefore an object of the present invention to provide a white sidewall that can be applied circumferentially in a groove of the black sidewall of a cured tire using heat and some pressure.
It is another object of the present invention to provide a white sidewall compound comprising blends of EPDM and EPR with thermoplastic crystallinity 10enhancing polymeric additives and non-black mineral fillers.
It is still another object of the present invention to provide a white sidewaU
compound that can be applied to the black sidewall of a tire without the use of adhesives.
Yet another object of the present invention is to provide a thermoplastic layer 15of material that can be interposed between the white sidewall and black sidewall of the tire for the application of the former thereto.
It is a further object of the present invention to provide a method for applying a white sidewall to the black sidewall of a tire, without the use of adhesives.
It is still another object of the present invention to provide a tire at least 20partially cured and having a black sidewall area featuring a circumferential groove to which a non-black mineral-filled, thermoplastic polymeric composition of matter is adhered.
In general the present invention relates to a non-black mineral-filled white sidewall compound prepared from a thermoplastic polymeric composition of matter 25comprising (A) 100 parts by weight of a polymer blend comprising (1) from at least about 10 to 95 parts by weight of a polyolefin having from about 0.5 to about 13percent by weight crystallinity, the polyolefins being prepared from monomers having at least 2 carbon atoms and mixtures thereof; and (2) from about 5 to 90 parts by weight of a thermoplastic crystallinity enhancing polymeric additive; (B) from about 20 to 200 30parts by weight of a filler selected from the group consisting of reinforcing and non-9201013 F~R.P.US0068 209~ 04 reinforcing fillers and mixtures thereof per 100 parts of the polymer blend; and (C) from about 20 to 150 parts by weight of a processing material and mixtures thereof, per 100 parts of the polymer blend; the white sidewall compound being adherable to conventional, cured tire sidewalls without the use of solvents or water-based adhesives.
Also included in the invention is a method for applying a thermoplastic non-black mineral-filled white sidewalI compound to conventionally cured tire sidewalls comprising the steps of providing a tire at least partially cured and having a sidewall;
applying an uncured non-black mineral-filled white sidewall compound to the tiresidewall to form a white sidewall; and bonding the white sidewall to the tire sidewall ur.der sufficient pressure and heat to provide acceptable adhesion without the use of a solvent or a water based adhesive.
The present invention also provides a tire having a sidewall area and a non-black mineral:filled white sidewall compound adhered thereto prepared from a thermoplastic polymeric composition of matter comprising (A) 100 parts by weight of 15 a polymer blend comprising (1) from at least about 10 to 95 parts by weight of a polyolefin having from about 0.5 to about 13 percent by weight crystallinity, the polyolefins being prepared from monomers having at least 2 carbon atoms and mixtures thereof; and (2) from about 5 to 90 parts by weight of a thermoplastic crystallinity u enhancing polymeric additive; (B) from about 20 to 200 parts by weight of a filler 20 selected from the group consisting of reinforcing and non-reinforcing fillers and mixtures thereof per 100 parts of the polymer blend; and (C) from about 20 to 150 parts by weight of a processing material and mixtures thereof, per 100 parts of the polymer blend.
At least one or more of the foregoing objects which shall become apparent 25 to those skilled in the art are described in greater detail with reference to the specification which follows.
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;
BRIEF DESCRIPrION OF THE DRAWINGS
Fig. 1 is a side elevation of a tire depicting a white sidewall;
Fig. 2 is a fragmentary enlarged section of the molded tire prior to forming a circumferential groove therein;
Fig. 3 is a fragmentary enlarged section of the tire depicted in Fig. 1 similar to Fig. 2 but depicting a circumferential groove in the sidewall area;
Fig. 4 is a fragmentary further enlarged cross-section, taken substantially along line 4-4 of Fig. l;
Fig. 5 is a further enlarged exploded section depicting the white sidewall of 10 the present invention, a layer of thermoplastic film and the circumferential groove in the black sidewall area of the tire; and, Fig. 6 is a diagrammatic flow chart presenting the steps of the method according to the present invention.
PRE~ERRED EMBODIl\~ENT OF TIIE INVENIION
As noted hereinabove, the white sidewall compounds used in the present invention comprise blends of EPDM, EPR or other similar olefin type polymers prepared from monomers having at least 2 carbon atoms. The term EPDM is used in the sense of its definition as found in ASTM-D-1418-85 and is intended to mean a20 terpolymer of ethylene, propylene and a diene monomer with the residual unsaturation portion of the diene in the side chain. Illustrative methods for preparing such terpolymers are found in U.S. Pat. No. 3,280,082, the disclosure of which is incorporated herein by reference. The preferred polymers have from about 50 to about 95 weight percent ethylene and from about zero to about 12 weight percent of the diene 25 with the balance of the polymer being propylene or some other similar olefin type polymer.
The diene monomer utilized in forming the EPDM terpolymer is preferably a non-conjugated diene. Illustrative examples of non-conjugated dienes which may be employedaredicyclopentadiene,alkyldicyclopentadiene, 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,4-heptadiene, 2-methyl-1,5-hexadiene, cyclooctadiene, 1,4-octadiene, 9201013 FIR.P.US0068 2093~-04 I ,7-octadiene,5-ethylidene-2-norbornene,5-n-propylidene-2-norbornene,5-(2-methyl-2-butenyl)-2-norbornene and the like. A typical EPDM is Vistalon~ MD-744 (Exxon Chemical Co.) a terpolymer having a Mooney Viscosity (ML14 at 125C) of about 52;
an ethylene/propylene (E/P) ratio of 60/40 weight percent and 2.7 weight percent of 5 unsaturation.
Particularly useful and preferred are EPDM's and EPR's having a high degree of crystallinity as opposed to amorphous (non-crystalline) EPDM's or EPR's, although the latter can also be employed. Examples thereof include Royalene~ 375- (Uniroyal Chemical Co.); and EPsyn~ 5508 and EPsyn0 MDE-249 (Copolymer Rubber 1~ & Chemical Corporation). Royalene~ 375 has a Mooney Viscosity (MLJ4 at 125C) of about 50.8; an E/P ratio of 75/25 weight percent and about 2.0 weight percent ofunsaturation (dicyclopentadiene) and a weight average molecular weight of approximately 190,000. EPsyn0 5508 has a Mooney Viscosity (ML/4 at 125C) of about 55.6; an E/P ratio of 73/27 weight percent and about 3.7 weight percent of15 unsaturation. EPsyn0 MDE-249, an experimental terpolymer has a Mooney Viscosity (ML/4 at -125C) of about 56; an E/P ratio of 71/29 weight percent and about 1.7weight percent of unsaturation (5-ethylidene-2-norbornene) can also be employed. Also useful in preparing a white sidewall compound for practice of the present invention is Vistalon0 MD-744 (Exxon Chemical Co.) an EPDM rubber having a Mooney Viscosity 20 (ML/4 at 125 C) of about 53; an ethylene/propylene (E/P) ratio of about 60/40 weight percent; about 2.7 weight percent of unsaturation (5-ethylidene-2-norbornene) and a weight average molecular weight of approximately 360,000. A more complete discussion of such polymers is set forth in our copending application, U.S. Ser. No.
07/594,457, the subject matter of which is incorporated herein by reference.
The term EPR is used in the sense of its definition as found in ASTM D-1418-85 and is intended to mean a copolymer of ethylene and propylene. The preferred copolymers contain from about 30 to 95 weight percent ethylene with the balance to total 100 weight percent being propylene. A typical EPR is Vistalon0 719 (Exxon Chemical Co.) having an E/P ratio of about 75/25 weight percent.
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Also, useful in forming the white sidewall compounds of the present invention is a copolymer of ethylene and butene. This particular copolymer has about 82 weight percent ethylene with the balance to total 100 weight percent being butene.
A typical ethylene/butene copolymer is GERS- 1085 (Union Carbide Corporation3 having an Mw, as measured by GPC of at least about 221,000. Other similar olefinic polymers (e.g., ethylene/octene copolymer) can be used to practice this invention. Generally speaking any polyolefin having more than about 2 percent by weight crystallinity and selected from the group consisting of polyolefins prepared from monomers containing at least 2 carbon atoms can be employed. For purposes of discussion herein, references - 10 to EPDM, EPR or similar olefinic polymers are intended to include any of the polyolefins of the present invention.
To be useful as a white sidewall compound in the present invention it is preferred that the EPDM have from about 0.5 up to about 13 weight percent crystallinity from the ethylene component; an Mn as measured by GPC of at least about 30,000 up -to about 120,000, and an Mw, as measured by GPC of at least about 100,000 up to about 375,000. Similarly, the EPR should have from about 0.5 weight percent to about 13 percent crystallinity (ethylene); an Mn, as measured by GPC of at least about 30,000 up to about 120,000, and an Mw, as measured by GPC of at least about 100,000 up to about 375,000. We have found that the selection of an EPDM or EPR having high crystallinity (at least 2 percent by weight) and weight average molecular weight (Mw = 100,000) is preferred to provide a white sidewall compound which does not re~uire curing prior to application, and which does not re~uire any type of adhesive, solvent-based or the like, to adhere the white sidewall to the black sidewall of the tire.
In addition to the foregoing polyolefins, amorphous polyolefins having up to about 0.5 percent by weight crystallinity and prepared from monomers having at least 2 carbon atoms can be employed. In order to have utility in this invention polyolefins having less than two weight percent crystallinity may be blended with varying amounts of one or more of the thermoplastic crystallinity enhancing polymeric additives listed in Table I. Again, for each of discussion, this component of the polymeric composition of matter may be referred to herein as EPDM, EPR or other polyolefin.
9201013 FIR.P.US0068 20~04 .
The thermoplastic crystallinity enhancing polymeric additives that may be employed in the polymer blends of thc present invention and are selected from the group consisting of polyolefin homopolymers, random copolymers and block copolymers.
Homopolymers include polyethylene and polypropylene. Random copolymers include 5 poly(ethylene~propylene) copolymers. Block copolymers include poly(ethylene-b-octene) and poly(ethylene-b-butene) copolymers. Mixtures of the foregoing polymers can be employed or a single polymer can be employed to comprise from about 10 to 95 `~ parts by weight of EPDM or EPR polymer blended with from about 5 to 90 parts by weight of a crystalline enhancing polymeric additive for a total of 100 parts of polymer.
10Typical examples of commercially available thermoplastic crystallinity enhancing polymeric additive additives that can be blended with EPDM, EPR or other similar polyolefims, materials have been set forth in Table I along with peak melt temperatures and percent of crystallinity by differential scanning calorimetry (DSC) at a heating rate of 10C per minute.
9201013 FIR.P.US0068 .
209~504 .. g TABLE I
Thermopl~stic Crystallinity Enhancin~ Polnneric Additives ETHYLENE HOMOPOLYMERS Tm. C* % crvstallinity POLYWAX 2000a 128 89.9 POLYWAX 3000b 121 93.2 LDPE 722C 112 39.1 LDPE 132d 109 27.7 LDPE 640e 113 39.9 LDPE 768f 119 45.8 LDPE CG-2523g 111 53.6 HDPE 12065h 134 66.8 HDPE 62013i 131 61.2 PETROLlTE E-202Q1 116 85.9 POLYPROPYLENE HOMOPOLYMERS
EASTOBOND D-?682-109Sk 153 4.7 A-FAX 5001 155 5.8 ETHYLENE/PROPYLENE COPOLYMERS
RLX-020m 152 35.8 ETHYLENE/OCTENE COPOLYMERS
ATTANE 4003n 123 36.9 ATTANE 4001 124 35.0 DOWLEX 2047AP 124 39.8 DOWLEX 2045q 124 42.2 DOWLEX 2038r 127 53.6 DOWLEX 2027S 113 41.5 ETHYLENE/BUTENE COPOLYMER
GERS-1085t 71 2.3 9201013 FIR.P.US0068 209~04 *) Peak Melt Temperature a) High melting polyethylene having a molecular weight of about 2000 (Petrolite) b) High melting polyethylene having a molecular weight of about 3000 (Petrolite) :r C) Low density polyethylene resin, density 0.916 (Dow Chemical) . . 5 d) Low density polyethylene resin, density 0.919 (Dow Chemical) . e) Low density polyethylene resin, density 0.922 (Dow Chemical) f) Low density polyethylene resin, density 0.930 (Dow Chemical) g) Low density polyethylene resin, density 0.923 (Dow Chemical) -` h) High density polyethylene resin, density 0.94 (Dow Chemical) i) High density polyethylene resin, density 0.94 (Dow Chemical) j) Petroleum-derived oxidized hydrocarbon having an acid number of 22 (Petrolite) k) Amorphous polypropylene (Eastman Chemical) 1) Amorphous polypropylene (Himont, USA, Inc.) m) Ethylene/propylene copolymer (2% Ethylene) molecular weight about 400,000 (Phillip's Petroleum) n) Ethylene-octene copolymer, density 0.905 (Dow Chemical) o) Ethylene-octene copolymer, density 0.912 ~Dow Chemical) p) Ethylene-octene copolymer, density 0.917 (Dow Chemical) q) Ethylene-octene copolymer, density 0.920 (Dow Chemical) r) Ethylene-octene copolymer, density 0.935 (Dow Chemical) s) Ethylene-octene copolymer, density 0.941 (Dow Chemical) t) Ethylene-butene copolymer (about 82% ethylene), density 0.884 (Union Carbide Corporation) The thermoplastic crystallinity enhancing polymeric additives are necessary, or of greater importance, when the polymer blend comprises increasing amounts ofpolyolefins having less than 2 percent by weight crystallinity. However, even if the 30 polyolefin selected is exclusively one having crystallinity greater than 2 percent by 9201013 FIR.P.US0068 209~ 04 weight, the presence of a thermoplastic crystallinity enhancing polymeric additive of the present invention provides deformation resistance, abrasion resistance, durability, blemish resistance and the like.
The composition employed to form the white sidewall compound comprises 5 a blend of 100 total parts by weight of EPDM,EPR or other similar type olefin type polymers, including mixtures of two or more types, and a thermoplastic crystallinity enhancing polymeric additive to which is added basically fillers and processing oil as well as optionally other components, all of which are discussed hereinbelow.
With respect first to the non-black mineral fillers, suitable fillers are selected 10 from the group comprising of hard clays, soft clays, chemically modified clays, calcined clays, mica, talc, alumina trihydrates, calcium carbonate, titanium dioxide, amorphous precipitated hydrated silica, silicates, silicon dioxide and mixtures thereof. These fillers may, either partially or completely replace "black" fillers, i.e. carbon black and other related petroleum-derived materials.
15Some four basic types of clays are normally used as reinforcing fillers for rubber elastomers. The different types of clay fillers include; airfloated, water washed, calcined and surface treated or chemically modified.
The airfloated clays are the least expensive and most widely used. They are divided into two general groups, hard and soft, and offer a wide range of reinforcement 20 and loading possibilities. Hard Clays are used in the amount of about 20 parts to about 200 parts per 100 parts of polymer (phr), preferably in an amount from about 65 to 175 phr. Any commercially available hard clay may be used. The preferred airfloated hard clays used are: Suprex0, Barden R0; LGB0 all commercially available from J.M.
Huber Corporation.
The airfloated soft clays are used in the amount of about 20 parts to about 200 parts per 100 parts of polymer(phr), prefera~ly in an amount from about 75 to 175 phr. The preferred airfloated soft clays used are Paragon0; Hi-White R0, and K-780 commercially available from J.M. Huber Corporation.
Water washed clays are normally considered as semi-reinforcing fillers. This 30 particular class of clays are more closely controlled for particle size by the water-9201013 FIR.P.US0068 2095~04 fractionation process. This process permits the production of clays within controlled particle size ranges. The preferred ranges of water washed clays are very similar to the preferred amounts of airfloated soft clays mentioned hereinabove. Some of the preferred water washed clays include Polyfil~ DL, Polyfil~ F, Polyfil~ FB, Polyfil~ HG-S 90, Polyfil0 K and Polyfil0 XB, all are commercially available from J.M. Huber Corporation.
The third type of clay includes the calcined clays. Clays normally contain approximately 14 percent water of hydration, and most of this can be removed by calcination. The amount of bound water removed determines the degree of calcination.
The preferred ranges of calcined clays are very similar to the preferred amounts of airfloated hard clays mentioned hereinabove. Some of the preferred calcined clays include Polyfil~ 40, Polyfil0 70, and Polyfil~ 80, all commercially available from J.M
Huber Corporation.
The final type of elay includes the chemically modified reinforcing clays.
Cross-linking ability is imparted to the clay by modifying the surface of the individual particles with a polyfunctional silane coupling agent. Chemically modified clays are used in the amount of about 20 parts to about 200 parts per 100 parts of polymer(phr), preferably in an amount from about 60 to 175 phr. Normally the specific gravity of most clays is about 2.60 at 25 C. The preferred chemically modified clays are commercially available from J.M. Huber Corporation and include: Nucap0 100, Nucap0 200, Nucap0 190, Nucap0 290, Nulok0 321, Nulok0 390 and Polyfil0 368.
Other useful non-black fillers include amorphous silica (silicon dioxide).
Silicas are generally elassed as wet-process, hydrated silicas because they are produced by a ehemical reaetion in water, from which they are precipitated as ultrafine, spherical partieles. Silica can be employed in the amount of about 20 parts to about 50 parts per 100 parts of polymer(phr), preferably in an amount from about 20 to 50 phr. The useful upper range is limited by the high viscosity imparted by fillers of this type. Some of the commereially available silicas whieh may be used inelude: Hi-Sil0 215, Hi-Sil~
233, Hi-Sil0 EP and Silene0 D all produced by PPG Industries. Also, a number of useful eommercial grades of different silicas are available from J.M. Huber Corporation.
9201013 FIR.P.US0068 ~ 209a~0~
Finely ground calcium carbonate is employed in the amount of about 20 parts to about 200 parts per 100 parts of polymer(phr), preferably in an amount from about 35 to 90 phr. Calcium carbonate generally has a specific gravity of about 2.71 and is commercially available from a number of suppliers including Harwick Chemical, J.M.
SHuber Corporation, Georgia Marble, Genstar Stone Products and Omya, Inc.
Titanium dioxide is employed in the amount of about 5 parts to about 80 parts per 100 parts of polymer(phr), preferably in an amount from about 10 to 50 phr.
Both the rutile and anatase form of titanium dioxide may be used, however, the rutile form is preferred and includes such products as TiPure~ R-960, which is a fine, white 10powder having a specific gravity of 3.90 and commercially available from DuPont Co.
Other commercially available non-black mineral fillers that may be employed to practice this invention include; talc (magnesium silicate), mica (mixtures of sodium and potassium aluminum silicate) and alumina trihydrate.
Optional ingredients include, for example, other elastomers (e.g., butyl 15elastomer, neutralized sulfonated EPDM, neutralized sulfonated butyl) in place of minor ! amounts of the EPDM, and conventional amounts of other conventional agents, such as zinc oxide, stearic acid, antioxidants, antiozonants, flame retardants, and the like.
With respect to the processing material, it is included to improve the processing behavior of the composition (i.e. reduce mixing time and increase rate of 20sheet forming) and includes processing oils, waxes and the like. The process oil is included in an amount ranging from about 20 parts to about 150 parts process oil phr, preferably in an amount ranging from about 60 parts to about 135 phr. A preferred processing oil is a paraffinic oil, e.g. Sunpar 150 which is available from the Sun Oil Company. Other petroleum derived oils including naphthenic oils are also useful.25The compounding ingredients can be admixed, utilizing an internal mixer (such as a Banbury rnixer), an extruder, and/or a two-roll mill, or other mixers suitable for forming a viscous relatively uniform admixture. When utilizing a type B Banbury internal mixer, in a preferred mode, the dry or powdery materials such as the fillers are added first followed by the liquid process oil and finally the polymer (this type of 30mixing can be referred to as an upside-down mixing technique).
9201013 FIR.P.US0068 2~9~04 During the construction of a tire, 20 to 30 mil film of uncured stain barrier skim stock is applied over the black sidewall in the region of the white sidewall circumferential groove. Once the tire has been properly cured, the white sidewall groove featuring a 20 to 30 mil film of the stain barrier skim is buffed before S application of the white sidewall compound. The white sidewall compound can be extruded into a circumferential groove which is located in the black sidewall region of the tire using heat and some pressure. The ideal temperature of the white sidewall extrudate is between about 205 and 320F (96 and 160C). The mineral-filled white sidewall compounds are self-adhering without the use of a solvent or water-basedadhesive. Also, due to the thermoplastic behavior of the mineral-filled EPDM/EPRcompositions of the present invention, a sulfur-accelerator cure package is not necessary.
Additionally, the thermoplastic EPDM/EPR compounds are expected to produce excellent ozone aging and weathering resistance. As noted hereinabove, the compositions can comprise EPDM, EPR or other polyolefin, as well as blends thereof.
The present invention can also utilize a thermoplastic film between the EPDM or EPR white sidewall compounds descAbed herein and the black sidewall to improve compatibility. The thin thermoplastic film of the present invention may comprise a polyolefin prepared from a monomer or monomers having from 2 to about8 carbon atoms, such as polyethylene, polypropylene, polybutene, polyoctene and the ;~ 20 like, as well as ethylene-vinyl acetate copolymers and blends thereof. Generally, the thickness of the film can range between from about 2 to about 20 mils although greater thicknesses may be employed and thus, are not precluded.
Mils of thickness and peak melt temperature (as determined using the Differential Scanning Calorimeter) for two high density polyethylene films used to practice the invention are provided in Table II.
9201013 FIR.P.US0068 ~0955~
Table II
Thermoplastic Films Liner Thickness (mils! Tm. C
(by DSC) High MW Polyethylene film pl50a 6 139.4 p5Soa 20 140.5 a) Stamylan UH~ (Engineering Plastics - DSM) In order to demonstrate practice of the present invention, three different white sidewall compounds, within the scope of the disclosure were prepared. The EPDM polymers selected included EPsyn~ MDE-249 and Vistalon~ MD-744.
Characterization of each of the polymers is presented in Table m hereinbelow.
, .
9201013 ~IR.P.US0068 209a504 TABLE m EPDM Polymer Characterization Studv EPsyn~ Vistalon~
ML14 at 125C 56 53 Ethylene Content, wt % 71 60 Crystallinity, wt % 9.3 <1 Tg, C ~by DSC) -47.5 -56.4 Tm, C (by DSC) 38.3 41.6 Unsaturation, % 1.7 2.7 Type of unsaturation E~a E~a Mn 106,0Q0 73,200 Mw 332,900 360,400 Mn/Mw ratio 3.14 4.92 15 a) 5-ethylidene-2-norbornene The white sidewall compounds of the present invention were prepared according to the formulation presented in Table IV hereinbelow. Parts and percentages 20 are by weight, unless otherwise indicated. These examples are submitted for the purpose of further illustrating the nature of the present invention and are not to be considered as a limitation on the scope thereof.
9201013 FIR.P.US0068 209 )~01 TABL,E IV
White Sidewall Compounds Comp~ound No. 1 2 3 Vistalon~ MD-744 60 EPsyn~ MDE-249 ~ - 60 60 Dowlex~ 2047Aa - - 40 NuCap~ 190 clay 20 20 20 TiO2 10 10 10 Sunpa~D 150 oilb 11 11 11 Ultramarine blueC 0.30 0.30 0.30 Antioxidantd TOTAL 142.3 142.3 142.3 ;; 15 a) ethylene-octene copolymer b) paraffinic process oil having a flash point of 495C, a refractive index of 1.4805 and specific gravity of 0.8740.
c) Inorganic blue pigment - prepared by heating a mixture of sulfur, clay, alkali and a reducing agent at high temperatures. A colorant for rubber products, especially white sidewall compounds.
d) 2,2' methylene-bis-(4-methyl-6-tert-butylphenol) In order to demonstrate practice of the present inventions, a conventional sulfur cured, black sidewall compound was prepared according to the formulation set forth in Table V hereinbelow to which the white sidewall compounds were adhered.
9201013 FIR.P.US0068 2~3-5~
TABLE V
Passen~er Black Sidewall Stock Polybutadiene 60 Natural rubber 40 S FEF carbon black (ASTM N-550) 55 Zinc oxide - 3 Stearic acid l.50 Santoflex 13a Wax blend 3.0 Antioxidantb 1.5 Naphthenic process oil 13.0 Rosin oil blendC 4.0 Rubber Masterbatch 184.33 Crystex sulfur 2.62 Santocure NSd 0.80 TOTAL 187.7', a) N-(l ,3-dimethylbutyl)-N'-phenyl-paraphenylenediamine b) Polymerized 2,2,4-trimethyl-1 ,2-dihydroquinoline c) Blend of petroleum hydrocarbons and tall oil rosin d) N-tert-butyl-2-benzothiazyl-sulfonamide It is also conventional to employ a stain barrier skim stock in tires having a white sidewall so as to protect the latter from staining caused by bleeding through of antioxidants, color of the aromatic process oils and the like which have a deleterious 25 effect on the white sidewall compound. The stain barrier skim stock composition is not novel to the present invention, a typical formulation being presented in Table VI
hereinbelow. The white sidewall compounds of the present invention were also adhered to the stain barrier stock.
9201013 FIR.P.US0068 2095~ 0~
TABLE VI
Stain BalTier ~kim Stock Skim Stock Natural rubber 30 Chlorobutyl 25 EPDM ~ 20 Polybutadiene 25 HAF black (ASTM N-330) 30 Naphthenic process oil 10 Wax blend 3 Alkyl phenol formaldehyde resin 2 Rubber Masterbatch 145.0 Rubber Masterbatch 145.0 Zinc oxide 3.0 Stearic acid 1.20 Crystex sulfur 2.62 : Altax-MBTSa 0.70 Vultac 7lob 117 TOTAL 153.69 a) Benzothiazyl disulfide b) alkyl phenol disulfide, sulfur content 29.4 to 31.8~ by weight, specific gravity 1.18 The thermoplastic white sidewall compositions provided in Table IV are tubed or extruded, preferably at a temperature in excess of 132C, into a circumferential groove located in the black sidewall of a cured tire. The groove itself is formed in the black sidewall during the curing of the tire. Prior to application of the thermoplastic 9201013 FIR.P.US0068 , :
2095~0~
white sidewall material the groove should be buffed, preferably with a wire brush.
Buffing removes mold release residue, as well as any surface "bloom'', i.e., sulfur, oils, etc., that may reduce the level of adhesion between the white and black sidewall.
Buffing also increases the amount of surface area between the thermoplastic white sidewall and cured tire. In order to minimize discoloration of the white sidewall, a stain barrier skim (about 20 to 30 mils in thickness) as shown in Table VI, can be applied to the black sidewall during construction of the uncured tire. The width and depth of the circumferential groove can vary.
With reference to the drawing figures, a conventional tire is depicted in Fig. 1 generally by the numeral 10. The tire 10 is typically pneumatic and comprises the tread 11, tread reinforcing belts 12, 13, body ply 14, inner liner 15, bead 16, first bead apex 18, bead toe 19, second bead apex 20, sidewall 21 and shoulder 22. Because the tire design can vary, it is to understood that the present invention is not to be limited by the construction of any particular tire, or to pneumatic tires as opposed to solid tires.
In the manufacture of a tire having a conventional white sidewall, it is customary to provide a stain barrier skim stock, the purpose of which is to inhibit the migration of processing oils, antioxidants and other components that would discolor or stain the white sidewall, A stain barrier skim stock 23 is depicted in Fig. 2 for such purpose and is otherwise a conventional component.
In order to apply the white sidewall, generally 25, to the tire 10, a circumferential groove 26 is provided, as depicted in Fig. 3. The circumferential groove 26 can be formed by buffing the sidewall 21, in the region depicted by arrow A in Fig. 2, after the tire has been cured or, it could be formed during cure in an appropriately designed tire mold using a metal ring. The size of the circumferential groove 26 can be varied depending upon the amount of white sidewall desired for current styling and appearance. Generally, it may be about 0.5 to 1 inch wide (1.25 to 2.5 cm) as shown at W and approximately 0.1875 inch (0.48 cm) deep, as shown at D, but not so deep as to exceed the thickness of the stain barrier skim stock 23. Acommon dimension is 0.75 inch wide (1.91 cm) and 0.1 inch deep (0.25 cm).
9201013 FIR.P.US0068 20~5504 The white sidewall 25 is applied to the circumferential groove 26 in an uncured state via suitable means, such as extrusion or the like. Preferably, a thin layer or sheet of the thermoplastic film 28 is applied between the circumferential groove 26 and white sidewall 25, to improve adhesion therebetween and provide additional stain 5 resistance. Nevertheless, the film 28 is optional.
Following application of the white sidewall 25, it is subjected to heat at about133 to 160C under slight pressure, on the order of about 8 to 200 psi, for about 5 to 30 seconds. This application of heat and pressure is sufficient to bond the white sidewaU to the stain barrier skim stock in the circumferential groove 26 without10 necessitating the use of solvents or water based adhesives, although use of either should not be construed as a means to practice outside the scope of the present invention. The white sidewaU 25 is preferably about 90 mils thick, shown at T, and provides an exterior surface 29 slightly below the exterior surface 30 of sidewall 21, as depicted in Fig. 4. Of course, the thickness of white sidewall 25 can be varied and may be equal 15 to or greater than the depth of the white sidewall 26.
Owing to the composition of the white sidewall 25, which is harder than conventional rubber compounds employed for white sidewalls, a more durable sidewaU
is obtained which has improved resistance to abrasion, scuffing, curbing, marring and the like. Moreover, because the white sidewall is applied after the tire has been 20 manufactured, the use of a cover strip to protect the conventional white sidewaU during building and curing is obviated as is the need for subsequent removal.
- Although practice of the present invention is preferred for use in the manufacture of newly manufactured tires, post cure, it is within the scope of the present invention to subject the tire to less than a total cure. Moreover, the method of the 2S present invention is not limited to newly manufactured tires, inasmuch as thecircumferential groove 26 could be buffed into existing tires for conversion to a white sidewaU tire. Thus, the application can be done at the point of sale in response to immediate demand. For such out-of-plant application, the method of the invention is currently carried out by applying the thermoplastic white sidewall compound in the form 30 of strips or a completely formed ring. Where desired, the thermoplastic film can be 9201013 liIR.P.US0068 2 0 9 a ~ 0 4 used and bonding may be facilitated by the application of heat, say in the amount of about 133-160C and pressure, say about ~ to about 200 psi.
Application of the white sidewall, according to the method of the present invention is set forth in the block diagram flow chart of Fig. 6 and includes as a first step providing a tire that is at least par~ially cNred and having a sidewall, box 31. Next, a circumferential groove is formed in the sidewall of the tire, during curing, box 32.
A non-black mineral-filled thermoplastic white sidewall compound is applied to the black sidewall of the tire, per box 33. Application includes the optional step of applying a thin sheet of thermoplastic film between the white sidewall compound and the black sidewall of the tire, box 34.
As discussed hereinabove, the preferred mode for the step of applying includes the step of providing a circumferential groove in the black sidewall, circumferentially positioned of the tire prior to curing, per box 32, or by buffing the circumferential groove into the black sidewall post cure, per box 35.
Following application of the white sidewall compound and optional thermoplastic-film to the circumferential groove, the method includes the step of bonding the white sidewaU via the application of heat and some pressure, box 36. Once the white sidewall component has cooled to room temperatures the tire is then ready for use.
Having thus described the physical construction of a typical tire to which the white sidewall of the present invention is applied, and the method for the application, test results have been reported which demonstrate the degree of adhesion that is obtained without the use of solvents, or water-based adhesives.
In the examples which follow, the white sidewall compound of Example 1 : 25 in Table IV was applied to the black sidewall compound of Table V with and without a layer of thermoplastic film therebetween. The composition exemplified is submitted for the purpose of further illustrating the nature of the present invention and is not to be considered as a limitation on the scope thereof. The white sidewall compounds of Table IV were also applied to the stain barrier skim stock compound of Table VI.
9201013 FIR.P.US0068 -23- 209.~0 Adhesion test pads of the various stock were prepared for peel adhesion testing according to the following procedure.
Detailed Peel Adhesion Test Procedure s A thermoplastic white sidewall compound and cured stain barrier skim were subjected to adhesion testing which necessitated the building of adhesion test pads comprising 6 x 6-inch unreinforced layers of rubber, according to the following procedure:
1. A 10 x 20-inch two-roll mill was utilized to prepare a number of 6 x 6-inch sheets of stain barrier skim approximately 75 mils in thickness or thermoplastic white sidewall approximately 25 mils in thickness for building rubber-to-rubber adhesion test pads.
2. The 75 mil 6 x 6-inch sheets of unreinforced stain barrier skim were cured in a . positive pressure mold for about 35 minutés at li9C~.
M~EI~AL FILLED EPDM/lEPR COMPOSlTIONS FOR
VVlIlTE SIDEWALL TII~E COMPOUNDS
S TEOEIN~CAL FIELD
The present invention relates generally to compositions for white sidewall tire compounds. The white sidewall tire compounds comprise a blend of ethylene-propylene-diene terpolymer, referred to herein as EPDM, ethylene-propylene copolymer, referred to herein as EPR, or other similar olefin type polymers or blends 10 thereof with a crystallinity enhancing thermoplastic polymeric additive such as a homopolymer of polyethylene or polypropylene as well as copolymers of ethylene/octene and ethylenelbutene or the like. More particularly the compounds contain non-black mineral fillers as replacements for carbon black. Oftentimes, a stain barrier skim (some 20 to 30 mils in thickness) is inserted at the interface of the black sidewall and white 15 sidewall compounds in order to prevent staining materials such as oils and antioxidants (i.e., p-phenylenediamines) from migrating into the white sidewall compound. Thewhite sidewall compound is adhered directly to the stain barrier skim (optional) or black sidewall of a solid or pneumatic tire using heat and some pressure and without solvents or water based adhesives. Moreover, a thin thermoplastic film can be provided between 20 the white sidewall compound and the stain barrier skim or black sidewall to improve adhesion therebetween.
.
BACKGROllND OF THE ~VENTION
Tires having white or decorative sidewalls are conventionally made by 25 building the white sidewall in place, applying a thin black cover strip thereover and curing the tire. The purpose of the cover strip is to protect the white sidewall during handling and curing so that it does not become discolored by contact with staining black components of the tire or mold residue materials. After the tire has been cured and cooled, the cover strip is buffed away, exposing the white sidewall. Nevertheless, the 30 white sidewall is relatively soft and can be subsequently blemished, marked or scuffed during shipment with other tires and general handling until it is installed onto a vehicle and thereafter.
9201013 FIR.P.US0068 2~95~0~1 Thus, the art has recognized a need for a white sidewall compound that has improved deformation resistance and durability over conventional compounds as well as a white sidewall that can be applied to a tire subsequent to cure, thereby obviating the need for the cover strip and subsequent removal operations. Also, the white 5 sidewall composition can be applied to a cured tire without the use of an adhesion system. An example of an uncured applique being co-cured with a green tire is described in U.S. Pat. No. 5,058,647 and an example of an uncured applique applied to a cured tire is described in U.S. Pat. No. 5,049,220. However, neither patentteaches the use of a tougher EPDM/EPR-based compound.
10Various EPDM compounds having high crystallinity are known but not the use thereof in white sidewalls. U.S. Patent No. 5,086,121, for instance, is directed toward a thermoplastic olefin composition. In this composition, there is provided a polyolefin component, such as high density polyethylene and two rubber components, only one of which is cured by a cure package. For example, the two rubbers employed 15 may include a halogenated butyl rubber and EPDM. A certain cure package, such as a zinc oxide system, is added so that only the halogenated butyl rubber is cured. The second rubber component remains uncured. A preferred EPDM is a highly crystalline terpolymer. Therefore, this pater~t discloses an uncured EPDM in the presence of a polyolefin such as a high density polyethylene. It is further noted that such a 20 composition provides improved physical properties, such as improved tensile strength and the like.
U.S. Patent No. 4,036,912 discloses a thermoplastic polymer blend of, for :-example, EPDM polymer with crystalline polypropylene. The blends achieve higher tensile strength and high structural integrity. No curing or cross linking agents are used 25 to obtain these characteristics. The polymers are mixed in a range of from about 5 parts by weight to about 200 parts by weight of polypropylene for every 100 parts by weight of EPDM.
.U.S. Patent No. 3,941,859 discloses a highly crystalline EPDM polymer blended with a polyolefin to form a blend having superior tensile strength. No cure .~
9201013 FIR.P.US0068 209a~0~
package is employed. Similarly, U.S. Patent No. 3,919,358 also discloses a crystalline EPDM blended with a polyolefin.
SUMl\/IARY OF THE I~VENTION
5It is therefore an object of the present invention to provide a white sidewall that can be applied circumferentially in a groove of the black sidewall of a cured tire using heat and some pressure.
It is another object of the present invention to provide a white sidewall compound comprising blends of EPDM and EPR with thermoplastic crystallinity 10enhancing polymeric additives and non-black mineral fillers.
It is still another object of the present invention to provide a white sidewaU
compound that can be applied to the black sidewall of a tire without the use of adhesives.
Yet another object of the present invention is to provide a thermoplastic layer 15of material that can be interposed between the white sidewall and black sidewall of the tire for the application of the former thereto.
It is a further object of the present invention to provide a method for applying a white sidewall to the black sidewall of a tire, without the use of adhesives.
It is still another object of the present invention to provide a tire at least 20partially cured and having a black sidewall area featuring a circumferential groove to which a non-black mineral-filled, thermoplastic polymeric composition of matter is adhered.
In general the present invention relates to a non-black mineral-filled white sidewall compound prepared from a thermoplastic polymeric composition of matter 25comprising (A) 100 parts by weight of a polymer blend comprising (1) from at least about 10 to 95 parts by weight of a polyolefin having from about 0.5 to about 13percent by weight crystallinity, the polyolefins being prepared from monomers having at least 2 carbon atoms and mixtures thereof; and (2) from about 5 to 90 parts by weight of a thermoplastic crystallinity enhancing polymeric additive; (B) from about 20 to 200 30parts by weight of a filler selected from the group consisting of reinforcing and non-9201013 F~R.P.US0068 209~ 04 reinforcing fillers and mixtures thereof per 100 parts of the polymer blend; and (C) from about 20 to 150 parts by weight of a processing material and mixtures thereof, per 100 parts of the polymer blend; the white sidewall compound being adherable to conventional, cured tire sidewalls without the use of solvents or water-based adhesives.
Also included in the invention is a method for applying a thermoplastic non-black mineral-filled white sidewalI compound to conventionally cured tire sidewalls comprising the steps of providing a tire at least partially cured and having a sidewall;
applying an uncured non-black mineral-filled white sidewall compound to the tiresidewall to form a white sidewall; and bonding the white sidewall to the tire sidewall ur.der sufficient pressure and heat to provide acceptable adhesion without the use of a solvent or a water based adhesive.
The present invention also provides a tire having a sidewall area and a non-black mineral:filled white sidewall compound adhered thereto prepared from a thermoplastic polymeric composition of matter comprising (A) 100 parts by weight of 15 a polymer blend comprising (1) from at least about 10 to 95 parts by weight of a polyolefin having from about 0.5 to about 13 percent by weight crystallinity, the polyolefins being prepared from monomers having at least 2 carbon atoms and mixtures thereof; and (2) from about 5 to 90 parts by weight of a thermoplastic crystallinity u enhancing polymeric additive; (B) from about 20 to 200 parts by weight of a filler 20 selected from the group consisting of reinforcing and non-reinforcing fillers and mixtures thereof per 100 parts of the polymer blend; and (C) from about 20 to 150 parts by weight of a processing material and mixtures thereof, per 100 parts of the polymer blend.
At least one or more of the foregoing objects which shall become apparent 25 to those skilled in the art are described in greater detail with reference to the specification which follows.
9201013 FIR.P.US0068 5 209~)aO~
;
BRIEF DESCRIPrION OF THE DRAWINGS
Fig. 1 is a side elevation of a tire depicting a white sidewall;
Fig. 2 is a fragmentary enlarged section of the molded tire prior to forming a circumferential groove therein;
Fig. 3 is a fragmentary enlarged section of the tire depicted in Fig. 1 similar to Fig. 2 but depicting a circumferential groove in the sidewall area;
Fig. 4 is a fragmentary further enlarged cross-section, taken substantially along line 4-4 of Fig. l;
Fig. 5 is a further enlarged exploded section depicting the white sidewall of 10 the present invention, a layer of thermoplastic film and the circumferential groove in the black sidewall area of the tire; and, Fig. 6 is a diagrammatic flow chart presenting the steps of the method according to the present invention.
PRE~ERRED EMBODIl\~ENT OF TIIE INVENIION
As noted hereinabove, the white sidewall compounds used in the present invention comprise blends of EPDM, EPR or other similar olefin type polymers prepared from monomers having at least 2 carbon atoms. The term EPDM is used in the sense of its definition as found in ASTM-D-1418-85 and is intended to mean a20 terpolymer of ethylene, propylene and a diene monomer with the residual unsaturation portion of the diene in the side chain. Illustrative methods for preparing such terpolymers are found in U.S. Pat. No. 3,280,082, the disclosure of which is incorporated herein by reference. The preferred polymers have from about 50 to about 95 weight percent ethylene and from about zero to about 12 weight percent of the diene 25 with the balance of the polymer being propylene or some other similar olefin type polymer.
The diene monomer utilized in forming the EPDM terpolymer is preferably a non-conjugated diene. Illustrative examples of non-conjugated dienes which may be employedaredicyclopentadiene,alkyldicyclopentadiene, 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,4-heptadiene, 2-methyl-1,5-hexadiene, cyclooctadiene, 1,4-octadiene, 9201013 FIR.P.US0068 2093~-04 I ,7-octadiene,5-ethylidene-2-norbornene,5-n-propylidene-2-norbornene,5-(2-methyl-2-butenyl)-2-norbornene and the like. A typical EPDM is Vistalon~ MD-744 (Exxon Chemical Co.) a terpolymer having a Mooney Viscosity (ML14 at 125C) of about 52;
an ethylene/propylene (E/P) ratio of 60/40 weight percent and 2.7 weight percent of 5 unsaturation.
Particularly useful and preferred are EPDM's and EPR's having a high degree of crystallinity as opposed to amorphous (non-crystalline) EPDM's or EPR's, although the latter can also be employed. Examples thereof include Royalene~ 375- (Uniroyal Chemical Co.); and EPsyn~ 5508 and EPsyn0 MDE-249 (Copolymer Rubber 1~ & Chemical Corporation). Royalene~ 375 has a Mooney Viscosity (MLJ4 at 125C) of about 50.8; an E/P ratio of 75/25 weight percent and about 2.0 weight percent ofunsaturation (dicyclopentadiene) and a weight average molecular weight of approximately 190,000. EPsyn0 5508 has a Mooney Viscosity (ML/4 at 125C) of about 55.6; an E/P ratio of 73/27 weight percent and about 3.7 weight percent of15 unsaturation. EPsyn0 MDE-249, an experimental terpolymer has a Mooney Viscosity (ML/4 at -125C) of about 56; an E/P ratio of 71/29 weight percent and about 1.7weight percent of unsaturation (5-ethylidene-2-norbornene) can also be employed. Also useful in preparing a white sidewall compound for practice of the present invention is Vistalon0 MD-744 (Exxon Chemical Co.) an EPDM rubber having a Mooney Viscosity 20 (ML/4 at 125 C) of about 53; an ethylene/propylene (E/P) ratio of about 60/40 weight percent; about 2.7 weight percent of unsaturation (5-ethylidene-2-norbornene) and a weight average molecular weight of approximately 360,000. A more complete discussion of such polymers is set forth in our copending application, U.S. Ser. No.
07/594,457, the subject matter of which is incorporated herein by reference.
The term EPR is used in the sense of its definition as found in ASTM D-1418-85 and is intended to mean a copolymer of ethylene and propylene. The preferred copolymers contain from about 30 to 95 weight percent ethylene with the balance to total 100 weight percent being propylene. A typical EPR is Vistalon0 719 (Exxon Chemical Co.) having an E/P ratio of about 75/25 weight percent.
9201013 FIR.P.US0068 : 2~9~0~
Also, useful in forming the white sidewall compounds of the present invention is a copolymer of ethylene and butene. This particular copolymer has about 82 weight percent ethylene with the balance to total 100 weight percent being butene.
A typical ethylene/butene copolymer is GERS- 1085 (Union Carbide Corporation3 having an Mw, as measured by GPC of at least about 221,000. Other similar olefinic polymers (e.g., ethylene/octene copolymer) can be used to practice this invention. Generally speaking any polyolefin having more than about 2 percent by weight crystallinity and selected from the group consisting of polyolefins prepared from monomers containing at least 2 carbon atoms can be employed. For purposes of discussion herein, references - 10 to EPDM, EPR or similar olefinic polymers are intended to include any of the polyolefins of the present invention.
To be useful as a white sidewall compound in the present invention it is preferred that the EPDM have from about 0.5 up to about 13 weight percent crystallinity from the ethylene component; an Mn as measured by GPC of at least about 30,000 up -to about 120,000, and an Mw, as measured by GPC of at least about 100,000 up to about 375,000. Similarly, the EPR should have from about 0.5 weight percent to about 13 percent crystallinity (ethylene); an Mn, as measured by GPC of at least about 30,000 up to about 120,000, and an Mw, as measured by GPC of at least about 100,000 up to about 375,000. We have found that the selection of an EPDM or EPR having high crystallinity (at least 2 percent by weight) and weight average molecular weight (Mw = 100,000) is preferred to provide a white sidewall compound which does not re~uire curing prior to application, and which does not re~uire any type of adhesive, solvent-based or the like, to adhere the white sidewall to the black sidewall of the tire.
In addition to the foregoing polyolefins, amorphous polyolefins having up to about 0.5 percent by weight crystallinity and prepared from monomers having at least 2 carbon atoms can be employed. In order to have utility in this invention polyolefins having less than two weight percent crystallinity may be blended with varying amounts of one or more of the thermoplastic crystallinity enhancing polymeric additives listed in Table I. Again, for each of discussion, this component of the polymeric composition of matter may be referred to herein as EPDM, EPR or other polyolefin.
9201013 FIR.P.US0068 20~04 .
The thermoplastic crystallinity enhancing polymeric additives that may be employed in the polymer blends of thc present invention and are selected from the group consisting of polyolefin homopolymers, random copolymers and block copolymers.
Homopolymers include polyethylene and polypropylene. Random copolymers include 5 poly(ethylene~propylene) copolymers. Block copolymers include poly(ethylene-b-octene) and poly(ethylene-b-butene) copolymers. Mixtures of the foregoing polymers can be employed or a single polymer can be employed to comprise from about 10 to 95 `~ parts by weight of EPDM or EPR polymer blended with from about 5 to 90 parts by weight of a crystalline enhancing polymeric additive for a total of 100 parts of polymer.
10Typical examples of commercially available thermoplastic crystallinity enhancing polymeric additive additives that can be blended with EPDM, EPR or other similar polyolefims, materials have been set forth in Table I along with peak melt temperatures and percent of crystallinity by differential scanning calorimetry (DSC) at a heating rate of 10C per minute.
9201013 FIR.P.US0068 .
209~504 .. g TABLE I
Thermopl~stic Crystallinity Enhancin~ Polnneric Additives ETHYLENE HOMOPOLYMERS Tm. C* % crvstallinity POLYWAX 2000a 128 89.9 POLYWAX 3000b 121 93.2 LDPE 722C 112 39.1 LDPE 132d 109 27.7 LDPE 640e 113 39.9 LDPE 768f 119 45.8 LDPE CG-2523g 111 53.6 HDPE 12065h 134 66.8 HDPE 62013i 131 61.2 PETROLlTE E-202Q1 116 85.9 POLYPROPYLENE HOMOPOLYMERS
EASTOBOND D-?682-109Sk 153 4.7 A-FAX 5001 155 5.8 ETHYLENE/PROPYLENE COPOLYMERS
RLX-020m 152 35.8 ETHYLENE/OCTENE COPOLYMERS
ATTANE 4003n 123 36.9 ATTANE 4001 124 35.0 DOWLEX 2047AP 124 39.8 DOWLEX 2045q 124 42.2 DOWLEX 2038r 127 53.6 DOWLEX 2027S 113 41.5 ETHYLENE/BUTENE COPOLYMER
GERS-1085t 71 2.3 9201013 FIR.P.US0068 209~04 *) Peak Melt Temperature a) High melting polyethylene having a molecular weight of about 2000 (Petrolite) b) High melting polyethylene having a molecular weight of about 3000 (Petrolite) :r C) Low density polyethylene resin, density 0.916 (Dow Chemical) . . 5 d) Low density polyethylene resin, density 0.919 (Dow Chemical) . e) Low density polyethylene resin, density 0.922 (Dow Chemical) f) Low density polyethylene resin, density 0.930 (Dow Chemical) g) Low density polyethylene resin, density 0.923 (Dow Chemical) -` h) High density polyethylene resin, density 0.94 (Dow Chemical) i) High density polyethylene resin, density 0.94 (Dow Chemical) j) Petroleum-derived oxidized hydrocarbon having an acid number of 22 (Petrolite) k) Amorphous polypropylene (Eastman Chemical) 1) Amorphous polypropylene (Himont, USA, Inc.) m) Ethylene/propylene copolymer (2% Ethylene) molecular weight about 400,000 (Phillip's Petroleum) n) Ethylene-octene copolymer, density 0.905 (Dow Chemical) o) Ethylene-octene copolymer, density 0.912 ~Dow Chemical) p) Ethylene-octene copolymer, density 0.917 (Dow Chemical) q) Ethylene-octene copolymer, density 0.920 (Dow Chemical) r) Ethylene-octene copolymer, density 0.935 (Dow Chemical) s) Ethylene-octene copolymer, density 0.941 (Dow Chemical) t) Ethylene-butene copolymer (about 82% ethylene), density 0.884 (Union Carbide Corporation) The thermoplastic crystallinity enhancing polymeric additives are necessary, or of greater importance, when the polymer blend comprises increasing amounts ofpolyolefins having less than 2 percent by weight crystallinity. However, even if the 30 polyolefin selected is exclusively one having crystallinity greater than 2 percent by 9201013 FIR.P.US0068 209~ 04 weight, the presence of a thermoplastic crystallinity enhancing polymeric additive of the present invention provides deformation resistance, abrasion resistance, durability, blemish resistance and the like.
The composition employed to form the white sidewall compound comprises 5 a blend of 100 total parts by weight of EPDM,EPR or other similar type olefin type polymers, including mixtures of two or more types, and a thermoplastic crystallinity enhancing polymeric additive to which is added basically fillers and processing oil as well as optionally other components, all of which are discussed hereinbelow.
With respect first to the non-black mineral fillers, suitable fillers are selected 10 from the group comprising of hard clays, soft clays, chemically modified clays, calcined clays, mica, talc, alumina trihydrates, calcium carbonate, titanium dioxide, amorphous precipitated hydrated silica, silicates, silicon dioxide and mixtures thereof. These fillers may, either partially or completely replace "black" fillers, i.e. carbon black and other related petroleum-derived materials.
15Some four basic types of clays are normally used as reinforcing fillers for rubber elastomers. The different types of clay fillers include; airfloated, water washed, calcined and surface treated or chemically modified.
The airfloated clays are the least expensive and most widely used. They are divided into two general groups, hard and soft, and offer a wide range of reinforcement 20 and loading possibilities. Hard Clays are used in the amount of about 20 parts to about 200 parts per 100 parts of polymer (phr), preferably in an amount from about 65 to 175 phr. Any commercially available hard clay may be used. The preferred airfloated hard clays used are: Suprex0, Barden R0; LGB0 all commercially available from J.M.
Huber Corporation.
The airfloated soft clays are used in the amount of about 20 parts to about 200 parts per 100 parts of polymer(phr), prefera~ly in an amount from about 75 to 175 phr. The preferred airfloated soft clays used are Paragon0; Hi-White R0, and K-780 commercially available from J.M. Huber Corporation.
Water washed clays are normally considered as semi-reinforcing fillers. This 30 particular class of clays are more closely controlled for particle size by the water-9201013 FIR.P.US0068 2095~04 fractionation process. This process permits the production of clays within controlled particle size ranges. The preferred ranges of water washed clays are very similar to the preferred amounts of airfloated soft clays mentioned hereinabove. Some of the preferred water washed clays include Polyfil~ DL, Polyfil~ F, Polyfil~ FB, Polyfil~ HG-S 90, Polyfil0 K and Polyfil0 XB, all are commercially available from J.M. Huber Corporation.
The third type of clay includes the calcined clays. Clays normally contain approximately 14 percent water of hydration, and most of this can be removed by calcination. The amount of bound water removed determines the degree of calcination.
The preferred ranges of calcined clays are very similar to the preferred amounts of airfloated hard clays mentioned hereinabove. Some of the preferred calcined clays include Polyfil~ 40, Polyfil0 70, and Polyfil~ 80, all commercially available from J.M
Huber Corporation.
The final type of elay includes the chemically modified reinforcing clays.
Cross-linking ability is imparted to the clay by modifying the surface of the individual particles with a polyfunctional silane coupling agent. Chemically modified clays are used in the amount of about 20 parts to about 200 parts per 100 parts of polymer(phr), preferably in an amount from about 60 to 175 phr. Normally the specific gravity of most clays is about 2.60 at 25 C. The preferred chemically modified clays are commercially available from J.M. Huber Corporation and include: Nucap0 100, Nucap0 200, Nucap0 190, Nucap0 290, Nulok0 321, Nulok0 390 and Polyfil0 368.
Other useful non-black fillers include amorphous silica (silicon dioxide).
Silicas are generally elassed as wet-process, hydrated silicas because they are produced by a ehemical reaetion in water, from which they are precipitated as ultrafine, spherical partieles. Silica can be employed in the amount of about 20 parts to about 50 parts per 100 parts of polymer(phr), preferably in an amount from about 20 to 50 phr. The useful upper range is limited by the high viscosity imparted by fillers of this type. Some of the commereially available silicas whieh may be used inelude: Hi-Sil0 215, Hi-Sil~
233, Hi-Sil0 EP and Silene0 D all produced by PPG Industries. Also, a number of useful eommercial grades of different silicas are available from J.M. Huber Corporation.
9201013 FIR.P.US0068 ~ 209a~0~
Finely ground calcium carbonate is employed in the amount of about 20 parts to about 200 parts per 100 parts of polymer(phr), preferably in an amount from about 35 to 90 phr. Calcium carbonate generally has a specific gravity of about 2.71 and is commercially available from a number of suppliers including Harwick Chemical, J.M.
SHuber Corporation, Georgia Marble, Genstar Stone Products and Omya, Inc.
Titanium dioxide is employed in the amount of about 5 parts to about 80 parts per 100 parts of polymer(phr), preferably in an amount from about 10 to 50 phr.
Both the rutile and anatase form of titanium dioxide may be used, however, the rutile form is preferred and includes such products as TiPure~ R-960, which is a fine, white 10powder having a specific gravity of 3.90 and commercially available from DuPont Co.
Other commercially available non-black mineral fillers that may be employed to practice this invention include; talc (magnesium silicate), mica (mixtures of sodium and potassium aluminum silicate) and alumina trihydrate.
Optional ingredients include, for example, other elastomers (e.g., butyl 15elastomer, neutralized sulfonated EPDM, neutralized sulfonated butyl) in place of minor ! amounts of the EPDM, and conventional amounts of other conventional agents, such as zinc oxide, stearic acid, antioxidants, antiozonants, flame retardants, and the like.
With respect to the processing material, it is included to improve the processing behavior of the composition (i.e. reduce mixing time and increase rate of 20sheet forming) and includes processing oils, waxes and the like. The process oil is included in an amount ranging from about 20 parts to about 150 parts process oil phr, preferably in an amount ranging from about 60 parts to about 135 phr. A preferred processing oil is a paraffinic oil, e.g. Sunpar 150 which is available from the Sun Oil Company. Other petroleum derived oils including naphthenic oils are also useful.25The compounding ingredients can be admixed, utilizing an internal mixer (such as a Banbury rnixer), an extruder, and/or a two-roll mill, or other mixers suitable for forming a viscous relatively uniform admixture. When utilizing a type B Banbury internal mixer, in a preferred mode, the dry or powdery materials such as the fillers are added first followed by the liquid process oil and finally the polymer (this type of 30mixing can be referred to as an upside-down mixing technique).
9201013 FIR.P.US0068 2~9~04 During the construction of a tire, 20 to 30 mil film of uncured stain barrier skim stock is applied over the black sidewall in the region of the white sidewall circumferential groove. Once the tire has been properly cured, the white sidewall groove featuring a 20 to 30 mil film of the stain barrier skim is buffed before S application of the white sidewall compound. The white sidewall compound can be extruded into a circumferential groove which is located in the black sidewall region of the tire using heat and some pressure. The ideal temperature of the white sidewall extrudate is between about 205 and 320F (96 and 160C). The mineral-filled white sidewall compounds are self-adhering without the use of a solvent or water-basedadhesive. Also, due to the thermoplastic behavior of the mineral-filled EPDM/EPRcompositions of the present invention, a sulfur-accelerator cure package is not necessary.
Additionally, the thermoplastic EPDM/EPR compounds are expected to produce excellent ozone aging and weathering resistance. As noted hereinabove, the compositions can comprise EPDM, EPR or other polyolefin, as well as blends thereof.
The present invention can also utilize a thermoplastic film between the EPDM or EPR white sidewall compounds descAbed herein and the black sidewall to improve compatibility. The thin thermoplastic film of the present invention may comprise a polyolefin prepared from a monomer or monomers having from 2 to about8 carbon atoms, such as polyethylene, polypropylene, polybutene, polyoctene and the ;~ 20 like, as well as ethylene-vinyl acetate copolymers and blends thereof. Generally, the thickness of the film can range between from about 2 to about 20 mils although greater thicknesses may be employed and thus, are not precluded.
Mils of thickness and peak melt temperature (as determined using the Differential Scanning Calorimeter) for two high density polyethylene films used to practice the invention are provided in Table II.
9201013 FIR.P.US0068 ~0955~
Table II
Thermoplastic Films Liner Thickness (mils! Tm. C
(by DSC) High MW Polyethylene film pl50a 6 139.4 p5Soa 20 140.5 a) Stamylan UH~ (Engineering Plastics - DSM) In order to demonstrate practice of the present invention, three different white sidewall compounds, within the scope of the disclosure were prepared. The EPDM polymers selected included EPsyn~ MDE-249 and Vistalon~ MD-744.
Characterization of each of the polymers is presented in Table m hereinbelow.
, .
9201013 ~IR.P.US0068 209a504 TABLE m EPDM Polymer Characterization Studv EPsyn~ Vistalon~
ML14 at 125C 56 53 Ethylene Content, wt % 71 60 Crystallinity, wt % 9.3 <1 Tg, C ~by DSC) -47.5 -56.4 Tm, C (by DSC) 38.3 41.6 Unsaturation, % 1.7 2.7 Type of unsaturation E~a E~a Mn 106,0Q0 73,200 Mw 332,900 360,400 Mn/Mw ratio 3.14 4.92 15 a) 5-ethylidene-2-norbornene The white sidewall compounds of the present invention were prepared according to the formulation presented in Table IV hereinbelow. Parts and percentages 20 are by weight, unless otherwise indicated. These examples are submitted for the purpose of further illustrating the nature of the present invention and are not to be considered as a limitation on the scope thereof.
9201013 FIR.P.US0068 209 )~01 TABL,E IV
White Sidewall Compounds Comp~ound No. 1 2 3 Vistalon~ MD-744 60 EPsyn~ MDE-249 ~ - 60 60 Dowlex~ 2047Aa - - 40 NuCap~ 190 clay 20 20 20 TiO2 10 10 10 Sunpa~D 150 oilb 11 11 11 Ultramarine blueC 0.30 0.30 0.30 Antioxidantd TOTAL 142.3 142.3 142.3 ;; 15 a) ethylene-octene copolymer b) paraffinic process oil having a flash point of 495C, a refractive index of 1.4805 and specific gravity of 0.8740.
c) Inorganic blue pigment - prepared by heating a mixture of sulfur, clay, alkali and a reducing agent at high temperatures. A colorant for rubber products, especially white sidewall compounds.
d) 2,2' methylene-bis-(4-methyl-6-tert-butylphenol) In order to demonstrate practice of the present inventions, a conventional sulfur cured, black sidewall compound was prepared according to the formulation set forth in Table V hereinbelow to which the white sidewall compounds were adhered.
9201013 FIR.P.US0068 2~3-5~
TABLE V
Passen~er Black Sidewall Stock Polybutadiene 60 Natural rubber 40 S FEF carbon black (ASTM N-550) 55 Zinc oxide - 3 Stearic acid l.50 Santoflex 13a Wax blend 3.0 Antioxidantb 1.5 Naphthenic process oil 13.0 Rosin oil blendC 4.0 Rubber Masterbatch 184.33 Crystex sulfur 2.62 Santocure NSd 0.80 TOTAL 187.7', a) N-(l ,3-dimethylbutyl)-N'-phenyl-paraphenylenediamine b) Polymerized 2,2,4-trimethyl-1 ,2-dihydroquinoline c) Blend of petroleum hydrocarbons and tall oil rosin d) N-tert-butyl-2-benzothiazyl-sulfonamide It is also conventional to employ a stain barrier skim stock in tires having a white sidewall so as to protect the latter from staining caused by bleeding through of antioxidants, color of the aromatic process oils and the like which have a deleterious 25 effect on the white sidewall compound. The stain barrier skim stock composition is not novel to the present invention, a typical formulation being presented in Table VI
hereinbelow. The white sidewall compounds of the present invention were also adhered to the stain barrier stock.
9201013 FIR.P.US0068 2095~ 0~
TABLE VI
Stain BalTier ~kim Stock Skim Stock Natural rubber 30 Chlorobutyl 25 EPDM ~ 20 Polybutadiene 25 HAF black (ASTM N-330) 30 Naphthenic process oil 10 Wax blend 3 Alkyl phenol formaldehyde resin 2 Rubber Masterbatch 145.0 Rubber Masterbatch 145.0 Zinc oxide 3.0 Stearic acid 1.20 Crystex sulfur 2.62 : Altax-MBTSa 0.70 Vultac 7lob 117 TOTAL 153.69 a) Benzothiazyl disulfide b) alkyl phenol disulfide, sulfur content 29.4 to 31.8~ by weight, specific gravity 1.18 The thermoplastic white sidewall compositions provided in Table IV are tubed or extruded, preferably at a temperature in excess of 132C, into a circumferential groove located in the black sidewall of a cured tire. The groove itself is formed in the black sidewall during the curing of the tire. Prior to application of the thermoplastic 9201013 FIR.P.US0068 , :
2095~0~
white sidewall material the groove should be buffed, preferably with a wire brush.
Buffing removes mold release residue, as well as any surface "bloom'', i.e., sulfur, oils, etc., that may reduce the level of adhesion between the white and black sidewall.
Buffing also increases the amount of surface area between the thermoplastic white sidewall and cured tire. In order to minimize discoloration of the white sidewall, a stain barrier skim (about 20 to 30 mils in thickness) as shown in Table VI, can be applied to the black sidewall during construction of the uncured tire. The width and depth of the circumferential groove can vary.
With reference to the drawing figures, a conventional tire is depicted in Fig. 1 generally by the numeral 10. The tire 10 is typically pneumatic and comprises the tread 11, tread reinforcing belts 12, 13, body ply 14, inner liner 15, bead 16, first bead apex 18, bead toe 19, second bead apex 20, sidewall 21 and shoulder 22. Because the tire design can vary, it is to understood that the present invention is not to be limited by the construction of any particular tire, or to pneumatic tires as opposed to solid tires.
In the manufacture of a tire having a conventional white sidewall, it is customary to provide a stain barrier skim stock, the purpose of which is to inhibit the migration of processing oils, antioxidants and other components that would discolor or stain the white sidewall, A stain barrier skim stock 23 is depicted in Fig. 2 for such purpose and is otherwise a conventional component.
In order to apply the white sidewall, generally 25, to the tire 10, a circumferential groove 26 is provided, as depicted in Fig. 3. The circumferential groove 26 can be formed by buffing the sidewall 21, in the region depicted by arrow A in Fig. 2, after the tire has been cured or, it could be formed during cure in an appropriately designed tire mold using a metal ring. The size of the circumferential groove 26 can be varied depending upon the amount of white sidewall desired for current styling and appearance. Generally, it may be about 0.5 to 1 inch wide (1.25 to 2.5 cm) as shown at W and approximately 0.1875 inch (0.48 cm) deep, as shown at D, but not so deep as to exceed the thickness of the stain barrier skim stock 23. Acommon dimension is 0.75 inch wide (1.91 cm) and 0.1 inch deep (0.25 cm).
9201013 FIR.P.US0068 20~5504 The white sidewall 25 is applied to the circumferential groove 26 in an uncured state via suitable means, such as extrusion or the like. Preferably, a thin layer or sheet of the thermoplastic film 28 is applied between the circumferential groove 26 and white sidewall 25, to improve adhesion therebetween and provide additional stain 5 resistance. Nevertheless, the film 28 is optional.
Following application of the white sidewall 25, it is subjected to heat at about133 to 160C under slight pressure, on the order of about 8 to 200 psi, for about 5 to 30 seconds. This application of heat and pressure is sufficient to bond the white sidewaU to the stain barrier skim stock in the circumferential groove 26 without10 necessitating the use of solvents or water based adhesives, although use of either should not be construed as a means to practice outside the scope of the present invention. The white sidewaU 25 is preferably about 90 mils thick, shown at T, and provides an exterior surface 29 slightly below the exterior surface 30 of sidewall 21, as depicted in Fig. 4. Of course, the thickness of white sidewall 25 can be varied and may be equal 15 to or greater than the depth of the white sidewall 26.
Owing to the composition of the white sidewall 25, which is harder than conventional rubber compounds employed for white sidewalls, a more durable sidewaU
is obtained which has improved resistance to abrasion, scuffing, curbing, marring and the like. Moreover, because the white sidewall is applied after the tire has been 20 manufactured, the use of a cover strip to protect the conventional white sidewaU during building and curing is obviated as is the need for subsequent removal.
- Although practice of the present invention is preferred for use in the manufacture of newly manufactured tires, post cure, it is within the scope of the present invention to subject the tire to less than a total cure. Moreover, the method of the 2S present invention is not limited to newly manufactured tires, inasmuch as thecircumferential groove 26 could be buffed into existing tires for conversion to a white sidewaU tire. Thus, the application can be done at the point of sale in response to immediate demand. For such out-of-plant application, the method of the invention is currently carried out by applying the thermoplastic white sidewall compound in the form 30 of strips or a completely formed ring. Where desired, the thermoplastic film can be 9201013 liIR.P.US0068 2 0 9 a ~ 0 4 used and bonding may be facilitated by the application of heat, say in the amount of about 133-160C and pressure, say about ~ to about 200 psi.
Application of the white sidewall, according to the method of the present invention is set forth in the block diagram flow chart of Fig. 6 and includes as a first step providing a tire that is at least par~ially cNred and having a sidewall, box 31. Next, a circumferential groove is formed in the sidewall of the tire, during curing, box 32.
A non-black mineral-filled thermoplastic white sidewall compound is applied to the black sidewall of the tire, per box 33. Application includes the optional step of applying a thin sheet of thermoplastic film between the white sidewall compound and the black sidewall of the tire, box 34.
As discussed hereinabove, the preferred mode for the step of applying includes the step of providing a circumferential groove in the black sidewall, circumferentially positioned of the tire prior to curing, per box 32, or by buffing the circumferential groove into the black sidewall post cure, per box 35.
Following application of the white sidewall compound and optional thermoplastic-film to the circumferential groove, the method includes the step of bonding the white sidewaU via the application of heat and some pressure, box 36. Once the white sidewall component has cooled to room temperatures the tire is then ready for use.
Having thus described the physical construction of a typical tire to which the white sidewall of the present invention is applied, and the method for the application, test results have been reported which demonstrate the degree of adhesion that is obtained without the use of solvents, or water-based adhesives.
In the examples which follow, the white sidewall compound of Example 1 : 25 in Table IV was applied to the black sidewall compound of Table V with and without a layer of thermoplastic film therebetween. The composition exemplified is submitted for the purpose of further illustrating the nature of the present invention and is not to be considered as a limitation on the scope thereof. The white sidewall compounds of Table IV were also applied to the stain barrier skim stock compound of Table VI.
9201013 FIR.P.US0068 -23- 209.~0 Adhesion test pads of the various stock were prepared for peel adhesion testing according to the following procedure.
Detailed Peel Adhesion Test Procedure s A thermoplastic white sidewall compound and cured stain barrier skim were subjected to adhesion testing which necessitated the building of adhesion test pads comprising 6 x 6-inch unreinforced layers of rubber, according to the following procedure:
1. A 10 x 20-inch two-roll mill was utilized to prepare a number of 6 x 6-inch sheets of stain barrier skim approximately 75 mils in thickness or thermoplastic white sidewall approximately 25 mils in thickness for building rubber-to-rubber adhesion test pads.
2. The 75 mil 6 x 6-inch sheets of unreinforced stain barrier skim were cured in a . positive pressure mold for about 35 minutés at li9C~.
3. The 6 x 6-inch unreinforced sheets of cured stain barrier skim were wire brush buffed using a 1.5-inch wide by ten-inch diameter wire brush wheel mounted on a floor model electric buffing machine.
4. A 25 mil thick 6 x 6-inch sheet of unreinforced thermoplastic white sidewall was applied to the buffed surface of the cured, unreinforced stain barrier skim. Thethermoplastic white sidewall - buffed, cured stain barrier skim combination was covered with a layer of mylar film and placed in the cavity of a metal curing mold - (cavity dimensions: 6 x 6 x 0.100-inch) ..
5. Adhesion pads consisting of 75 mils of a buffed, cured, unreinforced stain barrier skim and a 25 mil layer of an unreinforced thermoplastic white sidewall was 9201013 FIR.P.US0068 209~504 pressed for about six minutes in a 6 x 6 x 0.100-inch curing mold using very lowmolding pressure ( < 200 psi - press platens touching) and a curing temperature of about 149C. The adhesion test pads were allowed to equilibrate for 24 hours before testing.
S
S
6. Using a Clicker machine and~a one-inch wide metal die a number of six-inch long by one-inch wide test specimens were prepared for peel adhesion testing.
7. Testing machine: Model 1130 Instron~ Universal Tester - a testing machine of ,~` 10 the constant rate-ofjaw separation type. The machine was equipped with suitable grips capable of clamping the specimens firmly and without slippage throughout the tests.
8. The one-inch wide specimens were tested at the rate (both crosshead and chartspeed) of two inches per minute using the adhesion test set forth in ASTM D-413 (machine method). Peel adhesion strength was determined at room temperatur,e (i.e.; 230Cj as weli as occasionaliy at 38 and, 50C. ~est ,specim,ens were allowed 15 minutes' to preheat prior to testing at elevated temperatures.
20 9. Adhesion strength is measured as: peel adhesion strength ~bs/inch) = pounds force x sample width.
In Table VII the black sidewall of Table V, in both cured and uncured forms, and a white sidewall formulation in Example 1 of Table VI were joined together with and without a high density polyethylene liner. The thickness of the polyethylene 25 liner itself can be anywhere from 5 to 18 mils. Heat and pressure conditions were as specified.
9201013 FIR.P.US0068 2~95~04 .c ~
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209a~04 In Table VIII peel adhesion properties obtained for Examples No. 1-6 have been reported.
TABLE vm SPeel Adhesion Between Black Sidewall and W~hite Sidç~all Compounds Ex. No._ 1 2 3 4 5 6 Stock-to Stock Adhesion at 23C
lbs/inch 0.6 0.9 1.3 >38 ~35 >23 Type failure (A) (A) (A) (B) (B) (D) 10 Stock-to Stock Adhesion at 38C(a) lbs/inch -- -- -- > 18 >33 > 11 Type failure -- -- -- (B) (B) (C) Stoc_to Stock Adhesion at 50C(a) lbs/inch -- -- -- > 4.5 > 25 > 4 15 Type failure -- -- -- (C) (D) (C) ,: , .. ':
(a) Specimens preheated for 15 minutes prior to testing (A) = Separation occurred between the black sidewall/white sidewall compounds 20 (B) = Some tearing into the black sidewall compound. Chunks of black sidewall adhered to the HDPE liner, white sidewall showed some stretching and necking during testing (C) = The white sidewall compound elongated and broke during initial peel adhesion testing. Essentially no tearing resulted at the black sidewalVwhite sidewall interface (D) = The white sidewall compound experienced considerable stretching and necking before separating at the black sidewalVwhite sidewall interface.
At the failed interface, a thin, black film of black sidewall compound adhered to the white sidewall compound 9201013 FIR.P.US0068 '' 209~04 Next, in Table IX, 75 mil thick 6 x 6-inch slabs of cured stain barrier skim from Table VI were wire brush buffed via machine and individually molded to the three white sidewall compounds in Table IV using a curing mold for about six minutes using very low molding pressure ( < 200 psi - press platens touching) and a temperature of about 5 149C. No polyethylene film liner was employed. Peel adhesion tests at temperatures ranging from 23C to 50C were conducted and reported in Table IX.
TABLE ~
Peel Adhesion Between Stain Barrier Skim and White Sidewall Compounds Example No. 1 2 3 Stock-to-Stock Adhesion at 23C
lbs./inch > 10.2> 15.6> 18.2 Type failure (E) (E) (E) 15 Stock-to-Stock Adhesion at 38C(a) lbs./inch > 5.4> 8.3> 12.1 . Type failure (E) (E) ~E) Stock-to-Stock Adhesion at 50C(a) lbs./inch ~>3.8>5.7 >9.3 Type failure (E) (E) (E) (a) Specimens preheated for 15 minutes prior to testing (E) = The mineral-filled white sidewall compound experienced considerable stretching and some necking before separating at the stain barrier skim/white sidewall interface. At the failed interface, a thin, black film of stain barrier skim adhered to the surface of the white sidewall compound. Occasionally a small section of white sidewall compound was observed on the surface of the stain barrier skim.
. 9201013 ~IR.P.US0068 209a~
In conclusion, it should be clear from the foregoing examples and specification that the use of mineral-filled white sidewall compounds comprising a blend of semi-crystalline thermoplastic EPDM, EPR or other olefin-type polymers, with a thermoplastic crystallinity enhancing polymeric additive, provides a white sidewall 5 composition that can be adhered to the surface of the black sidewall of a cured tire using sufficient heat and some pressure and without the use of adhesives. Fully acceptable peel adhesion involving white sidewall and either wire brush buffed passenger black sidewall or stain barrier skim compounds resulted at test temperatures ranging from 23 to 50C without the use of a polyethylene liner. After peel adhesion testing small 10 sections (chunks) of white sidewall adhered to the surface of either the passenger black sidewall or the stain barrier skim. Additionally, a thermoplastic film can be interposed between the white sidewall and the black sidewall to improve adhesion further.
It is to be understood that the invention is not limited to the specific types of therrnoplastic films or EPDM exemplified herein or by the disclosure of other typical 15 EPDM, EPR or other olefin type polymers provided herein, or by the disclosure of crystalline enhancing polymers herein, the examples having been provided merely to : demonstrate the practice of the subject invention. Those skilled in the art may readily select other thermoplastic films, or other EPDM, EPR or other similar olefin polymers including copolymers of ethylene and butene and ethylene and octene, according to the 20 disclosure made hereinabove. Similarly, the invention is not ne essarily limited to the particular thermoplastic crystallinity enhancing polymeric additives, fillers and processing materials exemplified or the amounts thereof. Finally, although the present invention does not re~uire the use of solvents or adhesives between the white sidewall composition and the black sidewall, the use of either should not be construed as a means 25 to avoid practice of the invention.
Thus, it is believed that any of the variables disclosed herein can readily be determined and controlled without departing from the scope of the invention herein disclosed and described. Moreover, the scope of the invention shall include all modifications and variations that fall within the scope of the attached claims.
9201013 FIR.P.US0068
20 9. Adhesion strength is measured as: peel adhesion strength ~bs/inch) = pounds force x sample width.
In Table VII the black sidewall of Table V, in both cured and uncured forms, and a white sidewall formulation in Example 1 of Table VI were joined together with and without a high density polyethylene liner. The thickness of the polyethylene 25 liner itself can be anywhere from 5 to 18 mils. Heat and pressure conditions were as specified.
9201013 FIR.P.US0068 2~95~04 .c ~
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g ' ~ e a~
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<~n1n1~ T~TR P TT.Cn~;~
209a~04 In Table VIII peel adhesion properties obtained for Examples No. 1-6 have been reported.
TABLE vm SPeel Adhesion Between Black Sidewall and W~hite Sidç~all Compounds Ex. No._ 1 2 3 4 5 6 Stock-to Stock Adhesion at 23C
lbs/inch 0.6 0.9 1.3 >38 ~35 >23 Type failure (A) (A) (A) (B) (B) (D) 10 Stock-to Stock Adhesion at 38C(a) lbs/inch -- -- -- > 18 >33 > 11 Type failure -- -- -- (B) (B) (C) Stoc_to Stock Adhesion at 50C(a) lbs/inch -- -- -- > 4.5 > 25 > 4 15 Type failure -- -- -- (C) (D) (C) ,: , .. ':
(a) Specimens preheated for 15 minutes prior to testing (A) = Separation occurred between the black sidewall/white sidewall compounds 20 (B) = Some tearing into the black sidewall compound. Chunks of black sidewall adhered to the HDPE liner, white sidewall showed some stretching and necking during testing (C) = The white sidewall compound elongated and broke during initial peel adhesion testing. Essentially no tearing resulted at the black sidewalVwhite sidewall interface (D) = The white sidewall compound experienced considerable stretching and necking before separating at the black sidewalVwhite sidewall interface.
At the failed interface, a thin, black film of black sidewall compound adhered to the white sidewall compound 9201013 FIR.P.US0068 '' 209~04 Next, in Table IX, 75 mil thick 6 x 6-inch slabs of cured stain barrier skim from Table VI were wire brush buffed via machine and individually molded to the three white sidewall compounds in Table IV using a curing mold for about six minutes using very low molding pressure ( < 200 psi - press platens touching) and a temperature of about 5 149C. No polyethylene film liner was employed. Peel adhesion tests at temperatures ranging from 23C to 50C were conducted and reported in Table IX.
TABLE ~
Peel Adhesion Between Stain Barrier Skim and White Sidewall Compounds Example No. 1 2 3 Stock-to-Stock Adhesion at 23C
lbs./inch > 10.2> 15.6> 18.2 Type failure (E) (E) (E) 15 Stock-to-Stock Adhesion at 38C(a) lbs./inch > 5.4> 8.3> 12.1 . Type failure (E) (E) ~E) Stock-to-Stock Adhesion at 50C(a) lbs./inch ~>3.8>5.7 >9.3 Type failure (E) (E) (E) (a) Specimens preheated for 15 minutes prior to testing (E) = The mineral-filled white sidewall compound experienced considerable stretching and some necking before separating at the stain barrier skim/white sidewall interface. At the failed interface, a thin, black film of stain barrier skim adhered to the surface of the white sidewall compound. Occasionally a small section of white sidewall compound was observed on the surface of the stain barrier skim.
. 9201013 ~IR.P.US0068 209a~
In conclusion, it should be clear from the foregoing examples and specification that the use of mineral-filled white sidewall compounds comprising a blend of semi-crystalline thermoplastic EPDM, EPR or other olefin-type polymers, with a thermoplastic crystallinity enhancing polymeric additive, provides a white sidewall 5 composition that can be adhered to the surface of the black sidewall of a cured tire using sufficient heat and some pressure and without the use of adhesives. Fully acceptable peel adhesion involving white sidewall and either wire brush buffed passenger black sidewall or stain barrier skim compounds resulted at test temperatures ranging from 23 to 50C without the use of a polyethylene liner. After peel adhesion testing small 10 sections (chunks) of white sidewall adhered to the surface of either the passenger black sidewall or the stain barrier skim. Additionally, a thermoplastic film can be interposed between the white sidewall and the black sidewall to improve adhesion further.
It is to be understood that the invention is not limited to the specific types of therrnoplastic films or EPDM exemplified herein or by the disclosure of other typical 15 EPDM, EPR or other olefin type polymers provided herein, or by the disclosure of crystalline enhancing polymers herein, the examples having been provided merely to : demonstrate the practice of the subject invention. Those skilled in the art may readily select other thermoplastic films, or other EPDM, EPR or other similar olefin polymers including copolymers of ethylene and butene and ethylene and octene, according to the 20 disclosure made hereinabove. Similarly, the invention is not ne essarily limited to the particular thermoplastic crystallinity enhancing polymeric additives, fillers and processing materials exemplified or the amounts thereof. Finally, although the present invention does not re~uire the use of solvents or adhesives between the white sidewall composition and the black sidewall, the use of either should not be construed as a means 25 to avoid practice of the invention.
Thus, it is believed that any of the variables disclosed herein can readily be determined and controlled without departing from the scope of the invention herein disclosed and described. Moreover, the scope of the invention shall include all modifications and variations that fall within the scope of the attached claims.
9201013 FIR.P.US0068
Claims (32)
1. A non-black mineral-filled white sidewall compound prepared from a thermoplastic polymeric composition of matter comprising:
(A) 100 parts by weight of a polymer blend comprising (1) from at least about 10 to 95 parts by weight of a polyolefin having from about 0.5 to about 13 percent by weight crystallinity, said polyolefins being prepared from monomers having at least 2 carbon atoms and mixtures thereof; and (2) from about 5 to 90 parts by weight of a thermoplastic crystallinity enhancing polymeric additive;
(B) from about 20 to 200 parts by weight of a filler selected from the group consisting of reinforcing and non-reinforcing fillers and mixtures thereof per 100 parts of said polymer blend; and (C) from about 20 to 150 parts by weight of a processing material and mixtures thereof, per 100 parts of said polymer blend; said white sidewall compound being adherable to conventional, cured tire sidewalls without the use of solvents or water-based adhesives.
(A) 100 parts by weight of a polymer blend comprising (1) from at least about 10 to 95 parts by weight of a polyolefin having from about 0.5 to about 13 percent by weight crystallinity, said polyolefins being prepared from monomers having at least 2 carbon atoms and mixtures thereof; and (2) from about 5 to 90 parts by weight of a thermoplastic crystallinity enhancing polymeric additive;
(B) from about 20 to 200 parts by weight of a filler selected from the group consisting of reinforcing and non-reinforcing fillers and mixtures thereof per 100 parts of said polymer blend; and (C) from about 20 to 150 parts by weight of a processing material and mixtures thereof, per 100 parts of said polymer blend; said white sidewall compound being adherable to conventional, cured tire sidewalls without the use of solvents or water-based adhesives.
2. A non-black mineral-filled white sidewall compound, as set forth in claim 1, wherein said thermoplastic crystallinity enhancing polymeric additives are selected from the group consisting of polyethylene and polypropylene homopolymers;
poly(ethylene-co-propylene) random copolymers and poly(ethylene-b-octene) and poly(ethylene-b-butene) block copolymers.
poly(ethylene-co-propylene) random copolymers and poly(ethylene-b-octene) and poly(ethylene-b-butene) block copolymers.
3. A non-black mineral-filled white sidewall compound, as set forth in claim 1, wherein said polyolefin further comprises a diene monomer component.
9201013 FIR.P.US0068
9201013 FIR.P.US0068
4. A non-black mineral-filled white sidewall compound, as set forth in claim 3, wherein said polyolefin comprises EPDM.
5. A non-black mineral-filled white sidewall compound, as set forth in claim 4, wherein said EPDM has an ethylene content ranging from about 50 to 95 percent by weight, a weight average molecular weight of from about 100,000 to about 375,000 and from about 0.5 to about 13 percent by weight crystallinity.
6. A non-black mineral-filled white sidewall compound, as set forth in claim 5, wherein said EPDM has an ethylene content of about 71 percent by weight, a weight average molecular weight of about 332,000 and about 9.3 percent by weight crystallinity.
7. A non-black mineral-filled white sidewall compound, as set forth in claim 5, wherein said EPDM has an ethylene content of 60 percent by weight, a weight average molecular weight of about 360,000 and less than about one percent by weight crystallinity.
8. A non-black mineral-filled white sidewall compound, as set forth in claim 1, wherein said non-black mineral filler is selected from the group consisting of hard clays, soft clays, chemically modified clays, calcined clays, mica, talc, alumina trihydrates, calcium carbonate, titanium dioxide, amorphous precipitated hydrated silica, silicates, silicon dioxide and mixtures thereof.
9. A non-black mineral-filled white sidewall compound, as set forth in claim 8, wherein said processing material is selected from the group consisting of paraffinic oils, naphthenic oils and waxes and mixtures thereof.
9201013 FIR.P.US0068
9201013 FIR.P.US0068
10. A non-black mineral-filled white sidewall compound, as set forth in claim 9,wherein said mineral filler comprises about 20 parts by weight of a clay and said white sidewall compound includes about 11 parts by weight of processing oil.
11. A method for applying a thermoplastic non-black mineral-filled white sidewall compound to conventionally cured tire sidewalls comprising the steps of:
providing a tire at least partially cured and having a sidewall;
applying a non-black mineral-filled, thermoplastic white sidewall compound to said tire sidewall to form a white sidewall; and bonding said white sidewall to said tire sidewall under sufficient pressure and heat to provide acceptable adhesion without the use of a solvent or a water based adhesive.
providing a tire at least partially cured and having a sidewall;
applying a non-black mineral-filled, thermoplastic white sidewall compound to said tire sidewall to form a white sidewall; and bonding said white sidewall to said tire sidewall under sufficient pressure and heat to provide acceptable adhesion without the use of a solvent or a water based adhesive.
12. A method, as set forth in claim 11, wherein said non-black mineral-filled white sidewall compound is prepared by mixing together:
100 parts by weight of a polymer blend comprising (A) 100 parts by weight of a polymer blend comprising (1) from at least about 10 to 95 parts by weight of a polyolefin having from about 0.5 to about 13 percent by weight crystallinity, said polyolefins being prepared from monomers having at least 2 carbon atoms and mixtures thereof; and (2) from about 5 to 90 parts by weight of a thermoplastic crystallinity enhancing polymeric additive;
(B) from about 20 to 200 parts by weight of a filler selected from the group consisting of reinforcing and non-reinforcing fillers and mixtures thereof per 100 parts of said polymer blend; and (C) from about 20 to 150 parts by weight of a processing material and mixtures thereof, per 100 parts of said polymer blend.
9201013 FIR.P.US0068
100 parts by weight of a polymer blend comprising (A) 100 parts by weight of a polymer blend comprising (1) from at least about 10 to 95 parts by weight of a polyolefin having from about 0.5 to about 13 percent by weight crystallinity, said polyolefins being prepared from monomers having at least 2 carbon atoms and mixtures thereof; and (2) from about 5 to 90 parts by weight of a thermoplastic crystallinity enhancing polymeric additive;
(B) from about 20 to 200 parts by weight of a filler selected from the group consisting of reinforcing and non-reinforcing fillers and mixtures thereof per 100 parts of said polymer blend; and (C) from about 20 to 150 parts by weight of a processing material and mixtures thereof, per 100 parts of said polymer blend.
9201013 FIR.P.US0068
13. A method, as set forth in claim 12, wherein said thermoplastic crystallinity enhancing polymeric additives are selected from the group consisting of polyethylene and polypropylene homopolymers; poly(ethylene-co-propylene) random copolymers and poly(ethylene-b-octene) and poly(ethylene-b-butene) block copolymers.
14. A method, as set forth in claim 13, wherein said polyolefin further comprises a diene monomer component.
15. A non-black mineral-filled white sidewall compound, as set forth in claim 14, wherein said polyolefin comprises EPDM.
16. A non-black mineral-filled white sidewall compound, as set forth in claim 12, wherein said non-black mineral filler is selected from the group consisting of hard clays, soft clays, chemically modified clays, calcined clays, mica, talc, alumina trihydrates, calcium carbonate, titanium dioxide, amorphous precipitated hydrated silica, silicates, silicon dioxide and mixtures thereof.
17. A non-black mineral-filled white sidewall compound, as set forth in claim 16, wherein said processing material is selected from the group consisting of paraffinic oils, naphthenic oils and waxes and mixtures thereof.
18. A non-black mineral-filled white sidewall compound, as set forth in claim 17, wherein said mineral filler comprises about 20 parts by weight of a clay and said white sidewall compound includes about 11 parts by weight of processing oil.
19. A method, as set forth in claim 11, wherein said step of providing includes the steps of forming a circumferential groove in said sidewall of said tire for receipt of said thermoplastic white sidewall compound and cleaning said sidewall.
9201013 FIR.P.US0068
9201013 FIR.P.US0068
20. A method, as set forth in claim 19, including the additional step of applying a thermoplastic film to said circumferential groove prior to said step of applying said thermoplastic white sidewall compound to improve compatibility.
21. A method, as set forth in claim 11, including the additional step of applying a thermoplastic film to said sidewall prior to said step of applying said thermoplastic white sidewall compound to improve compatibility.
22. A method, as set forth in claim 11, wherein said step of bonding is conducted at a temperature of about 133° to about 160°C and a pressure of from about 8 to about 200 psi.
23. A tire having a sidewall area and a non-black mineral-filled white sidewall compound adhered thereto prepared from a thermoplastic polymeric composition of matter comprising:
(A) 100 parts by weight of a polymer blend comprising (1) from at least about 10 to 95 parts by weight of a polyolefin having from about 0.5 to about 13 percent by weight crystallinity, said polyolefins being prepared from monomers having at least 2 carbon atoms and mixtures thereof; and (2) from about 5 to 90 parts by weight of a thermoplastic crystallinity enhancing polymeric additive;
(B) from about 20 to 200 parts by weight of a filler selected from the group consisting of reinforcing and non-reinforcing fillers and mixtures thereof per 100 parts of said polymer blend; and (C) from about 20 to 150 parts by weight of a processing material and mixtures thereof, per 100 parts of said polymer blend.
(A) 100 parts by weight of a polymer blend comprising (1) from at least about 10 to 95 parts by weight of a polyolefin having from about 0.5 to about 13 percent by weight crystallinity, said polyolefins being prepared from monomers having at least 2 carbon atoms and mixtures thereof; and (2) from about 5 to 90 parts by weight of a thermoplastic crystallinity enhancing polymeric additive;
(B) from about 20 to 200 parts by weight of a filler selected from the group consisting of reinforcing and non-reinforcing fillers and mixtures thereof per 100 parts of said polymer blend; and (C) from about 20 to 150 parts by weight of a processing material and mixtures thereof, per 100 parts of said polymer blend.
24. A tire, as set forth in claim 23, wherein said thermoplastic crystallinity enhancing polymeric additives are selected from the group consisting of polyethylene and 9201013 FIR.P.US0068 polypropylene homopolymers; poly(ethylene-co-propylene) random copolymers and poly(ethylene-b-octene) and poly(ethylene-b-butene) block copolymers.
25. A tire, as set forth in claim 23, wherein said polyolefin further comprises a diene monomer component.
26. A tire, as set forth in claim 25, wherein said polyolefin comprises EPDM.
27. A non-black mineral-filled white sidewall compound, as set forth in claim 26, wherein said EPDM has an ethylene content ranging from about 50 to 95 percent by weight, a weight average molecular weight of from about 100,000 to about 375,000 and from about 0.5 to about 13 percent by weight crystallinity.
28. A tire, as set forth in claim 27, wherein said EPDM has an ethylene content of 71 percent by weight, a weight average molecular weight of about 332,000 and about 9.3 percent by weight crystallinity.
29. A tire, as set forth in claim 27, wherein said EPDM has an ethylene content of 60 percent by weight, a weight average molecular weight of about 360,000 and less than about one percent by weight crystallinity.
30. A tire, as set forth in claim 23, wherein said non-black mineral filler is selected from the group consisting of hard clays, soft clays, chemically modified clays, calcined clays, mica, talc, alumina trihydrates, calcium carbonate, titanium dioxide, amorphous precipitated hydrated silica, silicates, silicon dioxide and mixtures thereof.
31. A tire, as set forth in claim 30, wherein said processing material is selected from the group consisting of paraffinic oils, naphthenic oils and waxes and mixtures thereof.
9201013 FIR.P.US0068
9201013 FIR.P.US0068
32. A tire, as set forth in claim 31, wherein said mineral filler comprises about 20 parts by weight of a clay and said white sidewall compound includes about 11 parts by weight of processing oil.
9201013 FIR.P.US0068
9201013 FIR.P.US0068
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US88360692A | 1992-05-06 | 1992-05-06 | |
| US883,606 | 1992-05-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2095504A1 true CA2095504A1 (en) | 1993-11-07 |
Family
ID=25382939
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2095504 Abandoned CA2095504A1 (en) | 1992-05-06 | 1993-05-04 | Mineral filled epdm/epr compositions for white sidewall compounds |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPH0641374A (en) |
| CA (1) | CA2095504A1 (en) |
| MX (1) | MX9302561A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1091122C (en) * | 1998-12-17 | 2002-09-18 | 湖北大学化学与材料科学学院 | Ethylene propylene/polypropene blended thermoplastic elastic body and preparation method |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4707126B2 (en) * | 1998-12-04 | 2011-06-22 | 株式会社ブリヂストン | Non-adhesive rubber composition |
| KR101381647B1 (en) * | 2013-11-13 | 2014-04-07 | (주)유니텍 | The transfer pad for a tire |
-
1993
- 1993-04-30 JP JP5128228A patent/JPH0641374A/en active Pending
- 1993-04-30 MX MX9302561A patent/MX9302561A/en unknown
- 1993-05-04 CA CA 2095504 patent/CA2095504A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1091122C (en) * | 1998-12-17 | 2002-09-18 | 湖北大学化学与材料科学学院 | Ethylene propylene/polypropene blended thermoplastic elastic body and preparation method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0641374A (en) | 1994-02-15 |
| MX9302561A (en) | 1994-07-29 |
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