Continuously variable transmissions are lubricated by supplying to the transmission a composition of an oil of lubricating viscosity and an oil-soluble zinc salt containing at least one hydrocarbyl group of at least 4 carbon atoms. The amount of the zinc salt is sufficient to provide an increased steel-on-steel dynamic coefficient of friction for the composition, being at least 0.125. The composition is substantially free from thiophosphate salts and exhibits a copper corrosion rating of 1B or better (ASTM-130).

The present invention relates to compositions useful as transmission fluids, and particularly as fluids for continuously variable transmissions, and their use in lubricating continuously variable transmissions.
Continuously variable transmissions (CVT) represent a radical departure from conventional automatic transmission. The xe2x80x9cpush beltxe2x80x9d version of the CVT was invented by Dr. Hub Van Doorne, and since its introduction, many cars have been equipped with the push belt CVT system. CVTs are manufactured by Van Doorne""s Transmissie VB of Tilburg, the Netherlands. A more detailed description of such transmissions and belts and lubricants employed therein is found in U.S. Pat. No. 5,750,477, as well as references cited therein. In brief, a belt and pulley system is central to the operation of this type of transmission. The pulley system comprises a pair of pulleys with a V-shaped cross-section, each consisting of a moveable sheave, a fixed sheave, and a hydraulic cylinder. Between the pulleys runs a belt, which consists of a set of metal elements held together by metal bands. In operation, the driving pulley pushes the belt to the driven pulley, thereby transferring power from the input to the output. The transmission drive ratio is controlled by opening or closing the moveable sheaves so that the belt rides lower or higher on the pulley faces. This manner of operation permits continuous adjustment of gear ratio between the input and output shafts. Other types of belt-driven continuously variable transmissions are also known, including xe2x80x9cpull-beltxe2x80x9d transmissions in which a belt transmits force in tension rather than compression.
It has become clear from commercial use of the CVT that the fluids used in the CVT are just as important as the mechanical design for satisfactory operation. The lubricant must fulfill several functions: to lubricate the metal belt in its contacts with the pulley assembly, the planetary and other gears, the wet-plate clutches, and the bearings; to cool the transmission; and to carry hydraulic signals and power. The hydraulic pressure controls the belt traction, transmission ratio, and clutch engagement. The lubricant must provide the appropriate degree of friction between the belt and pulley assembly, to avoid the problem of slippage on one hand, and binding on the other, all the while providing protection to the metal surfaces from pitting, scuffing, scratching, flaking, polishing, and other forms of wear. Accordingly, the fluid should maintain a relatively high coefficient of friction for metal/metal contact, as well as exhibiting a suitable degree of shear stability.
Traction drives can be seen as another species of continuously variable transmission. These are typically devices in which power or torque is transmitted from an input element to an output element through nominal point or line contact, typically with a rolling action, by virtue of the traction between the contacting elements. Traction fluids and traction drives in which they can be used have been described for instance, in U.S. Pat. Nos. 4,693,134 and 5,043,497. While the working elements of a traction drive are sometimes spoken of as being in contact, it is generally accepted that a fluid film must be provided therebetween. Traction fluids and traction fluid compositions are employed in this context to provide power transmission by shearing of the film.
The present invention, therefore, solves the problem of providing fluids such as fluids for push-belt type and other continuously variable transmissions, which have increased metal-on-metal coefficient of friction while exhibiting low copper corrosion, by incorporating an oil soluble zinc salt into a fluid which is substantially free from thiophosphate salts.
European Patent Application 287 618, Dec. 9, 1992, discloses functional fluid compositions which comprise metal salts of an alkyl phosphoric acid ester. The metal-containing high torque, extreme pressure agent for a lubricating composition is prepared by reacting (A) a compound of the formula ROH with (B) a sulfur-free, phosphorus-containing agent to form an intermediate, and then further reacting said intermediate with (C) an oxide or hydroxide . . . of a metal selected from . . . zinc [among others] in the presence of (D) a catalytically effective amount of a proton source. The phosphorus acid esters are usually prepared from alcohols or alkyl phenols and phosphorus pentoxide. The amount of the composition employed in a lubricant will be about 0.05% to about 20%, preferably about 0.1% to about 10%.
U.S. Pat. No. 3,803,037, Wygant, Apr. 9, 1974, discloses cyclic carbon-containing compounds suited for use as a fluid component of tractive drives. The load-bearing capability is improved by incorporating minor amounts of zinc di(neo-alkyl)phosphorodithioate. In a (comparative) example, 2% of zinc 2-ethylhexyl isopropyl phosphorodithioate was tested and the coefficient of traction was measured.
The present invention provides a method for lubricating a continuously variable transmission, comprising supplying to said transmission a composition comprising an oil of lubricating viscosity and an oil-soluble zinc salt containing at least one hydrocarbyl group of at least 4 carbon atoms, in an amount sufficient to provide an increased steel-on-steel dynamic coefficient of friction for said composition, said coefficient of friction being at least 0.125, provided that said composition is substantially free from thiophosphate salts. The resulting composition exhibits a copper corrosion rating of 1B or better as measured by the procedure of ASTM-130 at 149xc2x0 C. for 3 hours.
Various preferred features and embodiments will be described below by way of non-limiting illustration.
The present invention provides a method for lubricating a continuously variable transmission (CVT). CVTs include both automotive and industrial transmissions, and include transmissions of both the push-belt design and the traction drive design.
The continuously variable transmissions of the present invention are lubricated by supplying to them a fluid. The fluid serves as more than a conventional lubricant since it must provide appropriate frictional or traction performance, and it can thus also be considered to be a functional fluid. The fluid composition comprises, first, an oil of lubricating viscosity, which is generally present in a major amount (i.e. an amount greater than 50% by weight). Generally, the oil of lubricating viscosity is present in an amount of greater than 80% by weight of the composition, typically at least 85%, preferably 90 to 98%. Such oil can be derived from a variety of sources, and includes natural and synthetic lubricating oils and mixtures thereof.
The natural oils useful in making the inventive lubricants and functional fluids include animal oils and vegetable oils (e.g., lard oil, castor oil) as well as mineral lubricating oils such as liquid petroleum oils and solvent treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinic/naphthenic types which may be further refined by hydrocracking and hydrofinishing processes and are dewaxed. Oils of lubricating viscosity derived from coal or shale are also useful. Useful natural base oils may be those designated by the American Petroleum Institute (API) as Group I, II, or III oils. Group I oils contain  less than 90% saturates and/or  greater than 0.03% sulfur and have a viscosity index (VI) of xe2x89xa780. Group II oils contain xe2x89xa790% saturates, xe2x89xa60.03% sulfur, and have a VI xe2x89xa780. Group III oils are similar to group II but have a VI xe2x89xa7120.
Upon occasion, highly refined or hydrocracked natural oils have been referred to as xe2x80x9csyntheticxe2x80x9d oils. More commonly, however, synthetic lubricating oils are understood to include hydrocarbon oils and halo-substituted hydrocarbon oils such as polymerized and interpolymerized olefins (e.g., polybutylenes, polypropylenes, propylene-isobutylene copolymers, chlorinated polybutylenes); poly(1-hexenes), poly(1-octenes), poly(1-decenes), and mixtures thereof; alkyl-benzenes (e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, di-(2-ethylhexyl)-benzenes); polyphenyls (e.g., biphenyls, terphenyls, alkylated polyphenyls); alkylated diphenyl ethers and alkylated diphenyl sulfides and the derivatives, analogs and homologs thereof and the like. Polyalpha olefin oils are also referred to as API Group IV oils.
Alkylene oxide polymers and interpolymers and derivatives thereof where the terminal hydroxyl groups have been modified such as by esterification or etherification constitute another class of known synthetic lubricating oils that can be used. These are exemplified by the oils prepared through polymerization of ethylene oxide or propylene oxide, the alkyl and aryl ethers of these polyoxyalkylene polymers (e.g., methyl-polyisopropylene glycol ether having an average molecular weight of about 1000, diphenyl ether of polyethylene glycol having a molecular weight of 500-1000, or diethyl ether of polypropylene glycol having a molecular weight of 1000-1500) or mono- and polycarboxylic esters thereof, for example, the acetic acid esters, mixed C3-8 fatty acid esters, or the C13Oxo acid diester of tetraethylene glycol.
Another suitable class of synthetic lubricating oils that can be used comprises the esters of dicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl succinic acids, alkenyl succinic acids, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl malonic acids, or alkenyl malonic acids) with a variety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, or propylene glycol). Specific examples of these esters include dibutyl adipate, di(2-ethylhexyl)sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic acid dimer, the complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid and the like.
Esters useful as synthetic oils also include those made from C5 to C12 monocarboxylic acids and polyols and polyol ethers such as neopentyl glycol, trimethylol propane, pentaerythritol, dipentaerythritol, or tripentaerythritol.
Silicon-based oils such as the polyalkyl-, polyaryl-, polyalkoxy-, or polyaryloxy-siloxane oils and silicate oils comprise another useful class of synthetic lubricants (e.g., tetraethyl silicate, tetraisopropyl silicate, tetra-(2-ethylhexyl)silicate, tetra-(4-methyl-hexyl)silicate, tetra-(p-tert-butylphenyl)silicate, hexyl-(4-methyl-2pentoxy)disiloxane, poly(methyl)siloxanes, poly-(methyl-phenyl)siloxanes). Other synthetic lubricating oils include liquid esters of phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl phosphate, diethyl ester of decane phosphonic acid), polymeric tetrahydrofurans and the like.
Unrefined, refined, and rerefined oils, either natural or synthetic (as well as mixtures of two or more of any of these) of the type disclosed hereinabove can be used in the lubricants of the present invention. Unrefined oils are those obtained directly from a natural or synthetic source without further purification treatment. For example, a shale oil obtained directly from retorting operations, a petroleum oil obtained directly from primary distillation or ester oil obtained directly from an esterification process and used without further treatment would be an unrefined oil. Refined oils are similar to the unrefined oils except they have been further treated in one or more purification steps to improve one or more properties. Many such purification techniques are known to those skilled in the art such as solvent extraction, secondary distillation, acid or base extraction, filtration, percolation, hydroprocessing, hydrocracking, and hydrotreating. Rerefined oils are obtained by processes similar to those used to obtain refined oils applied to refined oils which have been already used in service. Such rerefined oils are also known as reclaimed or reprocessed oils and often are additionally processed by techniques directed to removal of spent additives and oil breakdown products.
In one embodiment, the oil of lubricating viscosity is a poly-alpha-olefin (PAO). Typically, the poly-alpha-olefins are derived from monomers having from 4 to 30, or from 4 to 20, or from 6 to 16 carbon atoms. Examples of useful PAOs include those derived from 1-decene. These PAOs may have a viscosity from 2 to 150.
Preferred base oils include poly-xcex1-olefins such as oligomers of 1-decene. These synthetic base oils are hydrogenated resulting in an oil of stability against oxidation. The synthetic oils may encompass a single viscosity range or a mixture of high viscosity and low viscosity range oils so long as the mixture results in a viscosity which is consistent with the requirements set forth below. Also included as preferred base oils are highly hydrocracked and dewaxed oils. These petroleum oils are generally refined to give enhanced low temperature viscosity and antioxidation performance. Mixtures of synthetic oils with refined mineral oils may also be employed.
Another class of oils is known as traction oils or traction fluids, which are typically synthetic fluids containing a large fraction of highly branched or cycloaliphatic structures, e.g., cyclohexyl rings. Traction fluids are described in detail, for example, in U.S. Pat. Nos. 3,411,369 and 4,704,490. Certain types of base fluids are particularly suited for use in traction fluids because of their inherently good (high) traction coefficients. Two types of base fluids which are particularly suitable are (1) polymers of at least one olefin which contains 3 to 5 carbon atoms, and (2) hydrocarbon molecules containing non-aromatic cyclic moieties. Mixtures of these types of materials can also be used. For suitable performance, the base fluid should preferably have a viscosity of greater than 2.5xc3x9710xe2x88x926 m2/s (2.5 cSt) at 100xc2x0 C. (ASTM D-445), and more preferably a viscosity of at least 3.0xc3x9710xe2x88x926 m2/s (3.0 cSt) or 3.5xc3x9710xe2x88x926 m2/s (3.5 cSt), typically up to 8.0xc3x9710xe2x88x926 m2/s (8.0 cSt) or 7.0xc3x9710xe2x88x926 m2/s (7.0 cSt) or 6.0xc3x9710xe2x88x926 m2/s (6.0 cSt) at 100xc2x0 C.
Suitable base fluids of type (1) include polymers of branched olefins, preferably isobutylene, particularly those having a number average molecular weight of 180 to 2000, preferably 200 to 1000 or to 700. The polymer is preferably hydrogenated to remove any residual unsaturation. Such materials and their preparation are well known and are described, for instance, in U.S. Pat. No. 3,966,624, as component A, described particularly in column 12 line 32 through column 16 line 11.
Suitable base fluids of type (2) include a wide variety of cyclic-containing hydrocarbon molecules. Examples of these include di(cyclohexyl)alkanes, cyclohexyl hydrindans and adamantane compounds, as described in U.S. Pat. No. 3,966,624; esters of cyclohexanol and cylohexanecarboxylic acid, as described in U.S. Pat. No. 4,871,476; decalin, cycohexyldecalin, alkyl-substituted decalin, alkyl-substituted cyclohexyldecalin, and mixtures thereof, as described in U.S. Pat. No. 3,803,037; various materials having two cyclohexane rings linked by a methylene group described in U.S. Pat. No. 5,043,497; various hydrocarbon compounds having a bicyclooctane skeleton described in U.S. Pat. No. 5,422,027; hydrogenated products of dimers, trimers, or tetramers of norbornanes and/or norbornenes described in U.S. Pat. No. 5,126,065; hydrogenated dimers, trimers, or polymers of cyclic monoterpenoid monomers described in U.S. Pat. No. 4,975,215; various ter-cyclohexyl compounds disclosed in U.S. Pat. No. 5,850,745; perhydrofluorene derivatives disclosed in U.S. Pat. No. 4,774,013; and preferably linear dimers of hydrogenated xcex1-alkyl styrene, as described in U.S. Pat. No. 3,975,278. Any of the above materials may be used in a hydrogenated form, to assure the removal of carbon unsaturation; indeed, certain hydrogenated styrene derivatives (or cyclohexane derivatives) are inherently hydrogenated species. However, aromatic cyclic structures such as those derived from styrene may also be present in the base fluid, since aromatic cyclic structures are generally considered to be less deleterious than olefinic unsaturation.
The preferred materials for option (2) of the base fluid are predominantly linear dimers of hydrogenated xcex1-alkyl styrene. These dimers are said to be predominantly linear, in contrast to the cyclic dimers which represent another possible structure. Such preferred materials can be represented by the general structure
wherein each R is an alkyl group of 1 to 4 carbon atoms and C6H11 represents a cyclohexyl group. Such materials and their preparation are described in detail in U.S. Pat. No. 3,975,278. Indeed, the base fluid for the present composition preferably contains a major proportion of compounds represented as shown above.
Another component of the present fluid composition is an oil soluble zinc salt. There is no particular restriction on the type of zinc salt; however, it should not be a zinc thiophosphate or dithiophosphate material. While zinc dihydrocarbyldithiophosphates (ZDDPs) are widely known in the lubricating art, they should not be present in the present composition except perhaps in small and inconsequential amounts. Indeed, the lubricating composition should be substantially free from any thiophosphate derivatives, in order to provide a composition which exhibits minimal copper corrosion. In one embodiment, the lubricating composition is substantially free from compounds of all types containing active sulfur atoms. By xe2x80x9cactive sulfur atomsxe2x80x9d is meant sulfur atoms which are available (or are sufficiently labile to become available) to react with metal parts of a transmission. Besides elemental sulfur, materials which may contain or may generate active sulfur atoms include common anti-wear agent including sulfurized olefins, thiocarbamates, and dithiocarbamates. By xe2x80x9csubstantially freexe2x80x9d it is meant that the amount of the thiophosphate material is sufficiently low as to have no practically measurable effect on performance of the fluid, with regard to copper corrosion. In numerical terms this would normally correspond to an amount of zinc dialkyldithiophosphate of less than 200 parts per million in the composition, preferably less than 50 or 10 p.p.m.
Copper corrosion is measured by ASTM standard test number 130. The compositions used in the present invention, formulated to be substantially free from thiophosphate salts, will exhibit a copper corrosion rating of 1B or better when tested for 3 hours at 149xc2x0 C.
Oil-soluble zinc salts will be species which contain at least one hydrocarbyl group of at least 4, and preferably at least 6, carbon atoms. The hydrocarbyl group will generally be required in order to provide the required oil solubility, and its particular length or other characteristics may vary depending on the type of zinc salt involved. Suitable zinc salts include zinc phosphates, phosphites, phosphonates, sulfonates, carboxylates, phenates, and salicylates.
In one embodiment, the zinc salt is a zinc hydrocarbyl phosphate. The phosphate can be a mono- or dihydrocarbyl phosphate. The hydrocarbyl groups typically each independently contain 1 to 30 carbon atoms, preferably 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, provided, as stated above, that at least one hydrocarbyl group contains at least 6 carbon atoms. In a preferred embodiment, each hydrocarbyl is independently an alkyl or aryl group. When any group is an aryl group it typically contains 6 to 24 carbon atoms, more preferably 6 to 18 carbon atoms. Examples of hydrocarbyl groups include a butyl, amyl, hexyl, octyl, oleyl or cresyl, with octyl and cresyl being preferred.
The zinc hydrocarbyl phosphates can be prepared by reacting phosphorus acid or anhydride, preferably phosphorus pentoxide, with an alcohol at a temperature of 30xc2x0 C. to 200xc2x0 C., preferably 80xc2x0 C. to 150xc2x0 C., followed by neutralization with a zinc base. The phosphorus acid is generally reacted with the alcohol in a ratio of about 1:3.5, preferably 1:2. The product of such a reaction typically comprises a mixture of monohydrocarbyl and dihydrocarbyl zinc phosphates, typically being present in a relative ratios of about 1:1, or more generally, 2:1 to 1:2 or 3:1 to 1:3. Mixtures of about 1:1 monohydrocarbyl: dihydrocarbyl materials can be prepared by the simple stoichiometric reaction of alcohol with P2O5:
3ROH+P2O5xe2x86x92ROxe2x80x94P(xe2x95x90O)xe2x80x94(OH)2+(RO)2xe2x80x94P(xe2x95x90O)xe2x80x94OH
The alcohol can be any of the commercially available alcohols having an appropriate chain length, or mixtures of such alcohols. The alcohols can be aliphatic, cycloaliphatic, aromatic, or heterocyclic, including aliphatic-substituted cycloaliphatic alcohols, aliphatic-substituted aromatic alcohols, aliphatic-substituted heterocyclic alcohols, cycloaliphatic-substituted aliphatic alcohols, cycloaliphatic-substituted aromatic alcohols, cycloaliphatic-substituted heterocyclic alcohols, heterocyclic-substituted aliphatic alcohols, heterocyclic-substituted cycloaliphatic alcohols, and heterocyclic-substituted aromatic alcohols. The alcohols may contain non-hydrocarbon substituents of a type which do not interfere with the reaction of the alcohols with the phosphorus compound. The alcohols can be monohydric alcohols such as methanol, ethanol, isooctanol, 2-ethylhexanol, dodecanol, and cyclohexanol. Alternatively, the alcohols can be polyhydric alcohols, such as alkylene polyols such as ethylene glycols, including di-, tri- and tetraethylene glycols; propylene glycols, including di-, tri- and tetrapropylene glycols; glycerol; and the like. Also useful alcohols are mixed C18-C28 primary alcohols having mostly, on an alcohol basis, C22 alcohols. A variety of mixtures of monohydric fatty alcohols derived from naturally occurring triglycerides and ranging in chain length of from C8 to C18 are also useful, and are available from various sources including Procter and Gamble Company.
Another category of zinc salts includes the zinc carboxylates. These can be seen as the neutralization product of a zinc base and a carboxylic acid. As before, the carboxylic acid should contain at least 6 carbon atoms, to provide appropriate solubility. The carboxylic acids can be aliphatic or aromatic, mono- or polycarboxylic acids (or acid-producing compounds). These carboxylic acids include lower molecular weight carboxylic acids as well as higher molecular weight carboxylic acids (e.g. having more than 8 or more carbon atoms). Usually, in order to provide the desired solubility, the number of carbon atoms in a carboxylic acid should be at least about 8, e.g., 8 to 400, preferably 10 to 50, and more preferably 10 to 22.
Carboxylic acids include saturated and unsaturated acids. Examples of useful acids include dodecanoic acid, decanoic acid, tall oil acid, 10-methyl-tetradecanoic acid, 3-ethyl-hexadecanoic acid, and 8-methyl-octadecanoic acid, palmitic acid, stearic acid, myristic acid, oleic acid, linoleic acid, behenic acid, hexatriacontanoic acid, tetrapropylenyl-substituted glutaric acid, polybutenyl-substituted succinic acid derived from a polybutene ({overscore (Mn)}=200-1500), polypropenyl-substituted succinic acid derived from a polypropene, ({overscore (Mn)}=200-1000), octadecyl-substituted adipic acid, chlorostearic acid, 12-hydroxystearic acid, 9-methylstearic acid, dichlorostearic acid, ricinoleic acid, lesquerellic acid, stearyl-benzoic acid, eicosanyl-substituted naphthoic acid, dilauryl-decahydronaphthalene carboxylic acid, mixtures of any of these acids, their alkali and alkaline earth metal salts, their ammonium salts, their anhydrides, or their esters or triglycerides. A preferred group of aliphatic carboxylic acids includes the saturated and unsaturated higher fatty acids containing from about 12 to 30 carbon atoms. Other acids include aromatic carboxylic acids including substituted and non-substituted benzoic, phthalic and salicylic acids or anhydrides, most especially those substituted with a hydrocarbyl group containing about 6 to 80 carbon atoms. Examples of suitable substituent groups include butyl, isobutyl, pentyl, octyl, nonyl, dodecyl, and substituents derived from the above-described polyalkenes such as polyethylenes, polypropylenes, polyisobutylenes, ethylene-propylene copolymers, and oxidized ethylene-propylene copolymers.
An especially preferred zinc carboxylate is zinc oleate, which can be prepared by the neutralization of oleic acid by a basic zinc compound. Another zinc carboxylate is zinc salicylate.
The zinc compound can be a simple (neutral) salt, generally formed by straightforward stoichiometric acid-base neutralization of the acid with a zinc base such as zinc oxide or zinc hydroxide. The zinc salt can also be an overbased salt. Alternatively, the zinc salt can be a basic salt, in which one equivalent of a zinc base is reacted with somewhat less than one equivalent of acid, as described, for instance, in U.S. Pat. No. 5,110,488 (columns 9 and 10). An example of such a material is a slightly xe2x80x9cover-zinc-edxe2x80x9d oleate, that is, Zn4Oleate3O1. This is a species of overbased materials in general, which are well known to those skilled in the art and are generally disclosed in numerous patents such as U.S. Pat. No. 3,492,231 and especially the references cited therein.
The amount of the oil-soluble zinc salt should be sufficient to impart an increased steel-on-steel dynamic coefficient of friction for the formulation of at least 0.125, preferably 0.125 or 0.127 to 0.150, more preferably 0.130 to 0.140 or 0.135. The corresponding static coefficient of friction is 0.14 to 0.2 The coefficients of friction are measured at 110xc2x0 C. by ASTM G-77. The coefficient of friction of the formulation is improved, that is, increased over that of the same composition without the zinc salt.
The preferred amount of the oil soluble zinc salt, differently stated, is 0.05 to 1.0 percent by weight of the lubricant composition, preferably 0.2 to 0.5 weight percent. The zinc salt will preferably contribute up to 0.15 weight percent zinc to the composition, more preferably 0.01 to 0.1 weight percent.
The fluid used in the present invention may and will typically contain one or more additional additives suitable for use in a continuously variable transmission or an automatic transmission fluid (ATF). Such additional materials include other friction modifiers; and antioxidants, including hindered phenolic antioxidants, secondary aromatic amine antioxidants, oil-soluble copper compounds, and phosphorus-containing antioxidants. Other components include metal deactivators such as tolyltriazole, benzotriazole, and the methylene-coupled product of tolyltriazole and amines such as 2-ethylhexylamine. Such metal deactivators can also be useful in adjusting the metal-to-metal friction in push belt CVTs. Other components can include seal swell compositions, such as isodecyl sulfolane (that is, isodecyl-3-sulfolanyl ether), which are designed to keep seals pliable. Also permissible are pour point depressants, such as alkyl-naphthalenes, polymethacrylates, vinyl acetate/fumarate or /maleate copolymers, and styrene/maleate copolymers. Also included can be corrosion inhibitors, dyes, fluidizing agents, antifoam agents, dispersants, detergents, and anti-wear agents. These optional materials are known to those skilled in the art, are generally commercially available, and many are described in greater detail in published European Patent Application 761,805. Each of these materials may be present in conventional and functional amounts.
The composition of the present invention will normally be supplied as a fully formulated lubricant or functional fluid, or it can initially be prepared as a concentrate. In a concentrate, the relative amounts of the various components will generally be about the same as in the fully formulated composition, except that the amount of oil of lubricating viscosity will be decreased by an appropriate amount. The absolute percentage amounts of the remaining components will be correspondingly increased. Thus, when the concentrate is added to an appropriate amount of oil, the final formulation of the present invention will be obtained. A typical concentrate of the present invention may contain, for instance, 0.5 to 20 weight percent of the zinc salt, that is, about 10 times the concentration typically used in a final blend. An exhaustive listing of all the acceptable amounts and combinations in a concentrate on a parts-by-weight basis is not recited herein for the sake of brevity; however, such combinations can well be determined by the person skilled in the art seeking to prepare a concentrate.
As used herein, the term xe2x80x9chydrocarbyl substituentxe2x80x9d or xe2x80x9chydrocarbyl groupxe2x80x9d is used in its ordinary sense, which is well-known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of the molecule and having predominantly hydrocarbon character. Examples of hydrocarbyl groups include:
(1) hydrocarbon substituents, that is, aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, and aromatic-, aliphatic-, and alicyclic-substituted aromatic substituents, as well as cyclic substituents wherein the ring is completed through another portion of the molecule (e.g., two substituents together form a ring);
(2) substituted hydrocarbon substituents, that is, substituents containing non-hydrocarbon groups which, in the context of this invention, do not alter the predominantly hydrocarbon substituent (e.g., halo (especially chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso, and sulfoxy);
(3) hetero substituents, that is, substituents which, while having a predominantly hydrocarbon character, in the context of this invention, contain other than carbon in a ring or chain otherwise composed of carbon atoms. Heteroatoms include sulfur, oxygen, nitrogen, and encompass substituents as pyridyl, furyl, thienyl and imidazolyl. In general, no more than two, preferably no more than one, non-hydrocarbon substituent will be present for every ten carbon atoms in the hydrocarbyl group; typically, there will be no non-hydrocarbon substituents in the hydrocarbyl group.
Hydrocarbyl groups containing active sulfur may be avoided, if desired, to the extent that they may undesirably contribute to copper corrosion.
It is known that some of the materials described above may interact in the final formulation, so that the components of the final formulation may be different from those that are initially added. For instance, metal ions (of, e.g., a detergent) can migrate to other acidic sites of other molecules. The products formed thereby, including the products formed upon employing the composition of the present invention in its intended use, may not susceptible of easy description. Nevertheless, all such modifications and reaction products are included within the scope of the present invention; the present invention encompasses the composition prepared by admixing the components described above.

Method for lubricating a continuously variable transmission


A shoe (20) having a removable sole includes an upper (22) and a removable lower sole (34). The upper has an upper sole (24), a heel portion (26), and a toe portion (28). Upper sole (24) has a plurality of upwardly opening alignment holes (30). A lock tab (32) is connected to toe portion (28) and forwardly projects therefrom. The removable lower sole (34) has a heel portion (36) and a toe portion (38). A rearwardly opening slot (40) disposed in toe portion (38) is shaped and dimensioned to receive lock tab (32). Removable lower sole (34) has a plurality of upwardly protruding alignment pins (42) which are engageable with alignment holes (30) in upper sole (24). Lower sole (34) is held in place by inserting lock tab (32) into the rearwardly opening slot (40) in the toe and engaging connector (44) to connect heel portion (26) of upper (22) to heel portion (36) of lower sole (34).

The present invention pertains generally to footwear, and in particular to a shoe in which the sole portion may be selectively removed and replaced with another sole portion.
Shoes having replaceable soles are well known in the art. For example, U.S. Pat. No. 4,377,042 shows athletic footwear having a removable sole. Each upper is designed to fit an individual foot and ankle of a particular wearer and such upper is provided with a securely and permanently connected insole. Each insole terminates along its peripheral margin with one part of a bead-and-recess mechanically detachable locking member. A removable outsole is provided with a surface contacting tread which is selected to not only best match the surface of a particular sports area, but also the condition of such surface at a particular time of use. U.S. Pat. No. 5,317,822 illustrates an athletic shoe with interchangeable wear sole which can be selected to match a specific sport. An upper portion of the athletic shoe is designed for an individual foot of a particular wearer. This upper portion of the athletic shoe contains an attached upper sole which has molded on the bottom surface a plurality of strategically placed protruding resilient knobs, and a protruding edge rail which engages knob chambers and a rail slot located on the upper surface of the wear sole. Hook and loop fasteners such as sold under the trademark VELCRO on the upper sole and wear sole also are engaged. Interlocking devices on the edge of the upper sole and wear sole are pinned together. U.S. Pat. No. 5,353,522 defines a shoe having a removable sole portion. The shoe includes an upper and a sole, the sole including at least one fixed sole portion which fixed sole portion is fixedly attached to the upper. At least one removable sole portion is movable between a first position substantially adjacent to the fixed sole portion and a second position substantially separated from the fixed portion, the removable sole portion extending across the longitudinal axis of the shoe. A hinge apparatus provides a pivotal movement between the shoe and the removable sole portion, whereby the removable sole portion may be moved to the second position to provide access to the interior of the shoe without removal of the shoe from the foot of the wearer. U.S. Pat. No. 5,410,821 discloses a shoe with interchangeable soles. The invention is a sport shoe having a shoe upper with an interior for receiving a human foot and a bottom surface formed thereon, a removable foresole attached to a forward portion of the bottom surface of the shoe upper and having a toe receptacle for fitting against the toe area of the shoe upper, and a strap fastened to one side of the removable foresole and extending over the toe area of the shoe upper so as to removably fasten the foresole to the bottom side of the shoe upper. U.S. Pat. No. 5,615,497 portrays an improved athletic shoe sole with rotatable and replaceable cleats to provide the user with longer wear. The invention also provides the user with the ability to quickly and easily adapt the sole to different desired performance characteristics depending upon the intended activity and terrain or playing surface. U.S. Pat. No. 5,727,334 comprises a safety shoe with high-traction replaceable sole. A shoe having a replaceable sole pad for use by roofers is provided wherein the shoe has a thin lower flexible portion with a sheet or layer of hook fasteners of the hook-and-loop type fastener system disposed on a bottom surface thereof, and wherein a replaceable sole pad is provided having a sheet or layer of the corresponding loop elements provided on the upper surface thereof. The sole pad is constructed of high density, closed-cell foam that provides greatly improved traction on roofing surfaces, thereby improving worker safety, productivity and efficiency, and provides adequate durability to make the shoe with the replaceable soles cost justifiable.
The present invention is directed to a shoe which has an upper designed to fit the foot of a wearer, and a removable lower sole attached to the bottom of the upper. The upper can be fabricated from any conventional footwear material such as leather or canvas in sports, work shoe, dress shoe, and everyday shoe styles. A plurality of interchangeable removable lower soles can be selectively attached to the upper. The lower soles can be suited for a specific activity or sport such as football, baseball, track, hiking, and golf or for general walking. The lower soles can be fabricated from rubber, leather, or plastic, and can contain different bottom configurations such as cleats, spikes, ridges, and grooves or be flat.
The present invention allows the wearer to quickly and easily change the soles on his or her shoes to meet specific needs. The present shoe is ideally suited for those wearers who participate in a number of different indoor and outdoor activities or sports, allowing the same uppers to be used with a number of different removable lower soles, thereby eliminating the need to purchase multiple pairs of expensive shoes.
The present invention provides for the rapid changing of removable lower soles. Only one connector is used to effect the changing of lower soles.
In a preferred embodiment of the invention, a shoe comprises an upper having an upper sole, a heel portion, and a toe portion. The bottom of the upper sole has a plurality of upwardly opening alignment holes. A lock tab is connected to the toe portion and forwardly projects therefrom. A removable lower sole has a heel portion and a toe portion. A rearwardly opening slot is disposed in the toe portion, and is shaped and dimensioned to receive the lock tab. The removable lower sole has a plurality of upwardly protruding alignment pins that are engageable with the alignment holes in the upper sole. A connector selectively connects the heel portion of the upper to the heel portion of the removable lower sole.
In accordance with an important aspect of the invention, the connector includes a pivotable latch disposed upon the heel portion of the upper, and a cooperating bracket disposed upon the heel portion of the removable lower sole.
In accordance with an important feature of the invention, a plurality of removable lower soles are provided, each of the soles having a different bottom configuration.
Other features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.

Shoe having a removable sole and method of use


A recording media for phase change ink recording comprising: a support; 30-200 mg/dm2 of a receptive layer coated on the support wherein the receptive layer comprises: a binder comprising: a water soluble polymer; and a water insoluble polymer; wherein the combined weight of the water soluble polymer and the water insoluble polymer comprises at least 50%, by weight, and no more than 95%, by weight, water insoluble binder; and an optional inorganic particulate material. The media has an island size of no more than 15 xcexcm and an asperity of 5.0 to 6.2 xcexcm which is formed by controlling the drying rate.

The present invention is directed to an improved media for use with ink jet printers. More specifically, the present invention is directed to an improved media which is superior as a receptor for phase change ink printing.
Transparent films displaying information are widely used throughout many different industries and for many applications. Typically, a positive image is formed by placing an ink or pigment onto a transparent plastic sheet. The image is then displayed by projection of transmitted light.
Phase change ink printing has been demonstrated to be a superior method of printing. Among the advantages offered by phase change ink printing is the ability to obtain a high optical density and large print areas without the necessity for removing large volumes of solvent after printing. The impact of phase change ink printing for transparencies has been impeded due to the lack of a suitable media. Transparent media designed for use with aqueous ink jet printers are often used but these exhibit insufficient adhesion between the phase change ink and the media.
Phase change inks are characterized by their ability to remain in a solid state at ambient to warm conditions yet melt to a liquid at the printing head operating temperatures. Exemplary printing apparatus are disclosed, for example, in U.S. Pat. No. 5,276,468. The physical thermomechanical properties of the solid glassy state, the solid rubbery plateau state and the liquid melt are all important in the design of the phase change inks and printers. Exemplary phase change inks are provided, for example, in U.S. Pat. No. 5,372,852.
Contrary to solvent ink systems the phase change ink resides predominantly on the surface of the media and does not appreciably diffuse into the matrix of the media or coating. This phenomenon has challenged skilled artisans to develop a media which has suitable adhesion with the phase change inks. Media presently known in the art generates too weak of an adhesive bond to withstand even moderate impact. The prints delaminate easily during normal use. This is particularly a problem when large areas are printed.
Three methods are known in the adhesive art which increase the strength of the adhesive bond. The first is to increase the polarity of the surface to create high surface energy. This increases adhesion to the ink by a thermodynamic driving force to lower the total interfacial energy. The second increases the dispersive forces between media and ink by coating a primer with properties intermediate between the base polymer sheet and the ink. Using the rule that xe2x80x9clike dissolves likexe2x80x9d better anchorage results. However, neither approach provides the high impact resistance needed to avoid delamination in the impacted area. The third approach commonly used to improve adhesion increases the surface area. However, this results in large increases in surface haze, making the media no longer transparent.
Printing phase change ink at high percent surface coverage can negate high surface haze by filling in a rough surface. Thus, it is possible to create clarity by overprinting clear phase change ink in low image density areas. Using this approach, the high surface area approach to increased phase change ink anchorage can be made to be essentially transparent after printing. But high surface area alone is not effective in increasing the impact resistance to acceptable levels, particularly if the porosity is not filled in by the ink, either by its being too narrow in radial dimension or too deep into the coating. What is required is a particular porosity with a large number of accessible pores with anchorage sites which provide lock points for the congealed phase change ink.
There is a need for a media which will take full advantage of the properties offered by phase change ink printing. Provided herein is a coated media which exhibits excellent adhesion to phase change ink, offers adequate clarity, and greatly improves durability of the printed image as measured by increased resistance to ink removal.
Ink removal can either be from scratching with a hard object, adhesive removal by contact of the ink with an adhesive-containing object such as an adhesive tape, or by impact and consequent delamination of the phase change ink from the media surface. The first type of failure is largely a function of rheology of the phase change ink and as such is not addressed in the present invention. However, to the extent that ink is imbedded into the media as described in the present invention, removal by gouging with a blunt or sharp, hard object can be improved. Ink removal by adhesive contact is affected by the adhesion to the ink surface which depends in turn on its surface energy and as such is not addressed in the present invention. However, to the extent that the result actually loads the ink/media interface, a porous surface with ink imbedded into these pores breaks up the continuous failure line resulting in improved retention of ink at peel-like frequencies.
U.S. Pat. No. 5,753,360, which is commonly assigned, defines a media which is suitable for ink jet printing media. The results are based on a tape test which is a relatively mild test for adhesion. A more strenuous test, based on physical impact, indicates that a far superior film can be obtained which is described herein.
It is an object of the present invention to provide an improved recording media. A particular object is to provide a media which is suitable for use with phase change ink printing.
A particular feature of the present invention is improved resistance to physical removal of the phase change ink from the media.
Another particular feature is increased adhesion between the phase change ink and the media.
These and other advantages are provided in a recording medium for phase change ink recording comprising a polyethylene terephthalate support. Coated on the support is 1-200 mg/dm2 of a receptive layer. The receptive layer comprises: a binder comprising: 5-16%, by weight, polyvinyl alcohol; 70-85%, by weight, polymer comprising 10-100%, by weight, styrene and 0-90%, by weight, acrylic ester; 0.7-14%, by weight, acrylate; and 0.1-5%, by weight, inorganic particulate material.
A preferred process for obtaining the media is detailed in a process for forming a medium for phase change ink recording comprising the steps of:
a) Transporting a support through a coating station.
b) Applying a suspension to the support as the support transits through the coating station. The suspension comprises: water; a water soluble polymer; and a water insoluble polymer and the combined weight of the water soluble polymer and said water insoluble polymer is at least 50%, by weight, and no more than 95%, by weight, water insoluble polymer.
c) Removing the water from the suspension by evaporation to form a media herein the water soluble polymer and the water insoluble polymer have a combined coating weight on the media of at least 30 mg/dm2 and not more than 200 mg/dm2.
The inventive media comprises a support with a receptive layer coated thereon.
The receptive layer comprises a binder with an optional inorganic particulate material dispersed therein. The binder comprises a water soluble polymer and a water insoluble polymer.
The term xe2x80x9cwater soluble polymerxe2x80x9d refers specifically to a polymer which dissolves in water completely as characterized by the hydrodynamic particle diameter in water as measured by light scattering. For purposes of the present invention, a polymer with a light scattering hydrodynamic particle diameter, in water, of no more than 0.05 xcexcm indicates molecular scale dissolution. A polymer with a light scattering hydrodynamic particle diameter, in water, of no more than 0.05 xcexcm is referred to herein as a water soluble polymer. The water soluble polymer preferably comprises at least one compound chosen from a group consisting of polyvinyl alcohol, polyacrylamide, methyl cellulose, polyvinyl pyrrolidone and gelatin. The water soluble polymer more preferably comprises at least one element chosen from a group consisting of polyvinyl alcohol, polyacrylamide, polyvinyl pyrrolidone and gelatin. The most preferred water soluble polymer is polyvinylalcohol with a degree of hydrolysis between 70 and 100%.
The term xe2x80x9cwater insoluble polymerxe2x80x9d refers specifically to polymers which are described as consisting of a dispersion or emulsion of polymer in water and are characterized by the hydrodynamic particle diameter, in water, as determined by light scattering. A light scattering hydrodynamic particle diameter, in water, of greater than 0.05 xcexcm implies a dispersion of discrete particles containing one or more large molecule requiring stabilization by surfactants or other means to remain suspended. The water insoluble polymer preferably comprises at least one polymerizable monomer chosen from acrylic ester, olefin, aromatic substituted olefin, vinyl, aromatic substituted vinyl, urethane and unsaturated amide. The water insoluble polymers may comprise polar functionality with the proviso that the degree of functionality is below a level sufficient to form a water soluble polymer as characterized by having a hydrodynamic particle size of less than 0.05 xcexcm. A particularly preferred water insoluble polymer is styrene. More preferred is a polymer comprising 10-100%, by weight, styrene and 0-90%, by weight, acrylic ester. More preferred is a copolymer comprising 50-99%, by weight, styrene and 1-50%, by weight, acrylic ester. Most preferred is a copolymer comprising a styrene core and a shell comprising an acrylic acid, examples of which are described in U.S. Pat. Nos. 5,194,263; 5,214,096 and 5,460,263.
The ratio of water soluble polymer to water insoluble polymer is chosen to maximize the adhesion, as determined by impact resistance, and to take advantage of the ability of the phase change ink to adhere to the media while still maintaining adequate scratch protection. It is preferred that the combined weight of water soluble binder and water insoluble binder comprise at least 50%, by weight, water insoluble polymer. Below 50% water insoluble polymer adhesion unexpectedly deteriorates. It is more preferable that the combined weight of the water soluble and water insoluble polymer comprise at least 70%, by weight, water insoluble polymer and most preferably at least 80% by weight water insoluble polymer. It is preferred that the combined weight of the water soluble polymer and water insoluble polymer comprise no more than 95%, by weight, water insoluble polymer due to a decrease in adhesion between the media and the phase change ink.
A preferred media comprises a receptive layer comprising polyvinyl alcohol as the water soluble polymer and a polymer comprising styrene as the water insoluble polymer. More preferably, the water insoluble polymer is a polymer comprising 10-100% styrene and 0-90% acrylic ester. In the preferred media the polymer comprising styrene represents 50% to 95%, by weight, of the total weight of the polyvinyl alcohol and polymer comprising styrene. In a particularly preferred media the polymer comprising styrene represents 80% to 90%, by weight, of the total weight of the polyvinyl alcohol and polymer comprising styrene.
A particularly preferred media comprises a receptive layer comprising polyvinylalcohol as the water soluble polymer and a copolymer comprising a styrene core with a shell comprising acrylic ester.
A particularly preferred media comprises a receptive layer comprising: 5-16%, by weight, polyvinyl alcohol; 70-85%, by weight, of a polymer comprising 10-100%, by weight styrene and 0-90%, by weight, acrylic ester; and 0.7-14%, by weight acrylates; and 0.1-5%, by weight, silica. More preferred is 10-15%, by weight polyvinyl alcohol, and most preferred is 11-13%, by weight, polyvinyl alcohol. More preferred is 80-85%, by weight, polymer comprising 10-100%, by weight styrene and 0-90%, by weight, acrylic ester. Preferably the acrylates comprise 0.5-6%, by weight methyl acrylate; 0.1-3%, by weight, acrylic acid and 0.1-5%, by weight, sodium acrylate. Most preferred the acrylates comprise 1-2%, by weight, methyl acrylate; 0.8-1.2%, by weight, acrylic acid; and 1-2%, by weight sodium acrylate. The coating weight of the particularly preferred media is preferably 1-200 mg/dm2, more preferably 10-40 mg/dm2, even more preferably 15-35 mg/dm2 and most preferably 25-35 mg/dm2.
The inorganic particulate material is preferably chosen from a group consisting of colloidal silica and alumina. The preferred inorganic particulate material is silica with a hydrodynamic diameter in water of no more than 0.3 xcexcm. More preferably the inorganic particulate material has a hydrodynamic diameter in water of no more than 0.1 xcexcm. Also preferred as a particulate material is silica with a hydrodynamic diameter in water of no more than about 0.05 xcexcm. The silica is preferably at least 0.005 xcexcm. A hydrodynamic diameter in water between 0.005 xcexcm and 0.030 xcexcm with a specific surface area between 100 and 300 m2/g is particularly advantageous for superior adhesion. More preferred for adhesion is a silica hydrodynamic diameter in water of 0.010 to 0.020 xcexcm with a surface area of 200 to 300 m2/g. Scratch resistance is most improved with a silica hydrodynamic diameter in water of 0.01 to 0.015 xcexcm and a specific surface area of 200 to 250 m2/g.
A preferred colloidal silica for use in this invention is a multispherically coupled and/or branched colloidal silica. Specific examples are colloidal silica particles having a long chain structure in which spherical colloidal silica is coupled in a multispherical form. Also preferred is a colloidal silica in which the coupled silica is branched. Multispherically coupled colloidal silica is obtained by forming particle-particle bonds between primary particles of spherical silica by interspersing metal ions having a valence of two or more between the spherical silica particles. Preferably, the multispherically coupled colloidal silica has at least three particles coupled together. More preferably the multispherically coupled colloidal silica has at least five particles coupled together and most preferably the multispherically coupled colloidal silica has at least seven particles coupled together. The hydrodynamic diameter in water of the inorganic particulate material is determined as the diameter of a spherical particle with the same hydrodynamic properties as the sample in question. By way of example, a fibrous silica particle with dimensions of approximately 0.150 xcexcm by 0.014 xcexcm exhibits a hydrodynamic diameter in water of approximately 0.035 xcexcm.
The inorganic particulate matter of the receptive layer represents less than 50%, by weight, of the combined coating weight of the inorganic particulate matter, the water soluble polymer and the water insoluble polymer. In a preferred embodiment the inorganic particulate matter of the receptive layer represents less than 20%, by weight, of the combined coating weight of the inorganic particulate matter, the water soluble polymer and the water insoluble polymer. In a more preferred embodiment the inorganic particulate matter of the receptive layer represents less than 5%, by weight, of the combined coating weight of the inorganic particulate matter, the water soluble polymer and the water insoluble polymer.
It is most preferable to add a cross linker to the receptive layer to increase the strength of the dried coating. Aldehyde hardeners such as formaldehyde or glutaraldehyde are suitable hardeners for polyvinyl alcohol. Pyridinium based hardeners such as those described in, for example, U.S. Pat. Nos. 3,880,665, 4,418,142, 4,063,952 and 4,014,862 and imidazolium hardeners as defined in Fodor, et al, U.S. Pat. Nos. 5,459,029; 5,378,842; 5,591,863 and 5,601,971 are suitable for use in the present invention. Aziridenes and epoxides are also suitable hardeners.
Crosslinking is well known in the art to form intermolecular bonds between various molecules thereby forming a network. In the instant invention a crosslinker may be chosen to form intermolecular bonds between pairs of water soluble polymers, between pairs of water insoluble polymers, or between water soluble polymers and water insoluble polymers. If crosslinking is applied it is most preferable to crosslink the polymers to the inorganic particulate matter. It is preferable to apply any crosslinking additive just prior to or during coating. It is contemplated that the crosslinking may occur prior to formation of the coating solution or in situ.
The term xe2x80x9cgelatinxe2x80x9d as used herein refers to the protein substances which are derived from collagen. In the context of the present invention xe2x80x9cgelatinxe2x80x9d also refers to substantially equivalent substances such as synthetic analogues of gelatin. Generally gelatin is classified as alkaline gelatin, acidic gelatin or enzymatic gelatin. Alkaline gelatin is obtained from the treatment of collagen with a base such as calcium hydroxide, for example. Acidic gelatin is that which is obtained from the treatment of collagen in acid such as, for example, hydrochloric acid and enzymatic gelatin is generated with a hydrolase treatment of collagen. The teachings of the present invention are not restricted to gelatin type or the molecular weight of the gelatin with the proviso that after preparation of the gelatin a sufficient number of pendant carboxylic acid and amine groups remain for reactivity as taught herein. Carboxyl-containing and amine containing polymers, or copolymers, can be modified as taught herein so as to lessen water absorption without degrading the desirable properties associated with such polymers and copolymers.
Other materials can be added to the receptive layer to aid in coating and to alter the Theological properties of either the coating solution or the dried layer. Polymethylmethacrylate beads can be added to assist with transport through phase change ink printers. Care must be taken to insure that the amount of beads is maintained at a low enough level to insure that adhesion of the phase change ink to the substrate is not deteriorated. Preferably, the beads should represent no more than about 1.0% by weight of the receptive layer. It is conventional to add surfactants to a coating solution to improve the coating quality. Surfactants and conventional coating aids are compatible with the present invention.
The combined coating weight of the inorganic particulate matter, the water soluble polymer, and the water insoluble polymer is preferably more than 30 mg/dm2 and no more than 200 mg/dm2. Above 200 mg/dm2 the adhesion advantage diminishes and the increased cost of raw materials is not justified. It is more preferred that the combined coating weight of the inorganic particulate material, the water soluble polymer and the water insoluble polymer be at least 40 mg/dm2. Most preferred is a combined coating weight of the inorganic particulate material, the water soluble polymer and the water insoluble polymer of at least 60 mg/dm2 to insure adequate phase change ink adhesion and adequate resistance to scratching. A combined coating weight of the inorganic particulate material, the water soluble polymer and the water insoluble polymer of at least 50 mg/dm2 and no more than 200 mg/dm2 is a preferred range and most preferred is a combined coating weight of the inorganic particulate material, the water soluble polymer and the water insoluble polymer at least 40 mg/dm2 and no more than 100 mg/dm2.
The preferred support is a polyester obtained from the condensation polymerization of a diol and a dicarboxylic acid. Preferred dicarboxylic acids include terephthalate acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, adipic acid and sebacic acid. Preferred diols include ethylene glycol, trimethylene glycol, tetramethylene glycol and cyclohexanedimethanol. Specific polyesters suitable for use in the present invention are polyethylene terephthalate, polyethylene-p-hydroxybenzoate, poly-1,4-cyclohexylene dimethylene terephthalate, and polyethylene-2,6-naphthalenecarboxylate. Polyethylene terephthalate is the most preferred polyester for the support due to superior water resistance, excellent chemical resistance and durability. The polyester support is preferably 1-10 mil in thickness. More preferably the polyester support is 3-8 mil thick and most preferably the polyester support is either 3.5-4.5 mil or 6-8 mil thick. The receptive layer may also be applied to cellulose base media such as paper and the like.
A primer layer is preferably included between the receptive layer and the support to provide increased adhesion between the receptive layer and the support. Preferred primer layers are resin layers or antistatic layers. Resin and antistatic primer layers are described, for example, in U.S. Pat. Nos. 3,567,452; 4,916,011; 4,701,403; 4,891,308; and 4,225,665, and 5,554,447.
The primer layer is typically applied and dry-cured during the manufacture of the polyester support. When polyethylene terephthalate is manufactured for use as a photographic support, the polymer is cast as a film, the mixed polymer primer layer composition is applied to one or both sides and the structure is then biaxially stretched. The biaxial stretching is optionally followed by coating of either a gelatin subbing layer or an antistatic layer. Upon completion of the stretching and the application of the primer layer compositions, it is necessary to remove strain and tension in the support by a heat treatment comparable to the annealing of glass. Air temperatures of from 100xc2x0 C. to 160xc2x0 C. are typically used for this heat treatment.
It is preferable to activate the surface of the support prior to coating to improve the coating quality thereon. The activation can be accomplished by corona-discharge, glow-discharge, UV-rays or flame treatment. Corona-discharge is preferred and can be carried out to apply an energy of 1 mw to 1 kW/m2. More preferred is an energy of 0.1 w to 5 w/m2.
Bactericides may optionally be added to the receptive layer or the primer layer to prevent bacteria growth. Preferred are Kathon(copyright), neomycin sulfate, and others as known in the art.
An optional, but preferred backing layer can be added opposite the receptive layer to decrease curl, impart color, assist in transport, and other properties as common to the art. The backing layer may comprise cross linkers to assist in the formation of a stronger matrix. Preferred cross linkers for the backing layer are carboxyl activating agents as defined in Weatherill, U.S. Pat. No. 5,391,477. Most preferred are imidazolium hardeners as defined in Fodor, et al, U.S. Pat. Nos. 5,459,029; 5,378,842; 5,591,863; and 5,601,971. Aziridine and epoxy crosslinkers are also suitable crosslinkers. The backing layer may also comprise transport beads such as polymethylmethacrylate. It is known in the art to add various surfactants to improve coating quality. Such teachings are relevant to the backing layer of the present invention.
Phase change inks are characterized, in part, by their propensity to remain in a solid phase at ambient temperature and in the liquid phase at elevated temperatures in the printing head. The ink is heated to the liquid phase and droplets of liquid ink are ejected from the printing head. When the ink droplets contact the surface of the printing media they quickly solidify to form a pattern of solid ink drops. This process is known as direct ink jet printing. Other devices deliver the liquid ink droplets to a heated drum, maintained just below the melting temperature of the phase change inks. The patterned ink is then transferred from the drum in the rubbery state to the media under pressure. This process is known as indirect printing.
The phase change ink composition comprises the combination of a phase change ink carrier and a compatible colorant. The thermomechanical properties of the carrier are adjusted according to the mode of printing and further to match the precise parameters of the printer design. Thus each printer design has a matching optimized ink.
Exemplary phase change ink colorants comprise a phase change ink soluble complex of (a) a tertiary alkyl primary amine and (b) dye chromophores having at least one pendant acid functional group in the free acid form. Each of the dye chromophores employed in producing the phase change ink colorants are characterized as follows: (1) the unmodified counterpart dye chromophores employed in the formation of the chemical modified dye chromophores have limited solubility in the phase change ink carrier compositions, (2) the chemically modified dye chromophores have at least one free acid group, and (3) the chemically modified dye chromophores form phase change ink soluble complexes with tertiary alkyl primary amines. For example, the modified phase change ink colorants can be produced from unmodified dye chromophores such as the class of Color Index dyes referred to as Acid and Direct dyes. These unmodified dye chromophores have limited solubility in the phase change ink carrier so that insufficient color is produced from inks made from these carriers. The modified dye chromophore preferably comprises a free acid derivative of an xanthene dye.
The tertiary alkyl primary amine typically includes alkyl groups having a total of 12 to 22 carbon atoms, and preferably from 12 to 14 carbon atoms. The tertiary alkyl primary amines of particular interest are produced by Rohm and Haas, Incorporated of Houston, Tex. under the trade names Primene JMT and Primene 81-R. Primene 81-R is the preferred material. The tertiary alkyl primary amine of this invention comprises a composition represented by the structural formula:
wherein:
x is an integer of from 0 to 18;
y is an integer of from 0 to 18; and
z is an integer of from 0 to 18;
with the proviso that the integers x, y and z are chosen according to the relationship:
x+y+z=8 to 18.
Exemplary phase change ink carriers typically comprise a fatty amide containing material. The fatty amide-containing material of the phase change ink carrier composition preferably comprises a tetraamide compound. The preferred tetra-amide compounds for producing the phase change ink carrier composition are dimeric acid-based tetra-amides which preferably include the reaction product of a fatty acid, a diamine such as ethylene diamine and a dimer acid. Fatty acids having from 10 to 22 carbon atoms are preferably employed in the formation of the dimer acid-based tetra-amide. These diner acid-based tetramides are produced by Union Camp and comprise the reaction product of ethylene diamine, dimer acid, and a fatty acid chosen from decanoic acid, myristic acid, stearic acid and docasanic acid. The preferred dimer acid-based tetraamide is the reaction product of dimer acid, ethylene diamine and stearic acid in a stoichiometric ratio of 1:2:2, respectively. Stearic acid is the preferred fatty acid reactant because its adduct with diner acid and ethylene diamine has the lowest viscosity of the diner acid-based tetra-amides.
The fatty amide-containing material can also comprise a mono-amide. In fact, in the preferred case, the phase change ink carrier composition comprises both a tetra-amide compound and a mono-amide compound. The mono-amide compound typically comprises either a primary or secondary mono-amide, but is preferably a secondary mono-amide. Of the primary mono-amides stearamide, such as Kemamide S, manufactured by Witco Chemical Company, can be employed. As for the secondary mono-amides behenyl behemamide and stearyl stearamide are extremely useful mono-amides.
Another way of describing the secondary mono-amide compound is by structural formula. More specifically a suitable secondary mono-amide compound is represented by the structural formula:
CxHyxe2x80x94COxe2x80x94NHCaHb
wherein:
x is an integer from 5 to 21;
y is an integer from 11 to 43;
a is an integer from 6 to 22; and
b is an integer from 13 to 45.
The preferred fatty amide-containing materials comprise a plurality of fatty amide materials which are physically compatible with each other. Typically, even when a plurality of fatty amide-containing compounds are employed to produce the phase change ink carrier composition, the carrier composition has a substantially single melting point transition. The melting point of the phase change ink carrier composition is preferably at least about 70xc2x0 C., more preferably at least 80xc2x0 C. and most preferably at least 85xc2x0 C.
The preferred phase change ink carrier composition comprises a tetra-amide and a mono-amide. The weight ratio of the tetra-amide to the mono-amide in the preferred instance is from about 2:1 to 1:10 and more preferably from about 1:1 to 1:3.
Modifiers can be added to the carrier composition to increase the flexibility and adhesion. A preferred modifier is a tackifier. Suitable tackifiers are compatible with fatty amide-containing materials and include, for example, Foral 85, a glycerol ester of hydrogenated abietic acid, and Foral 105, a pentaerythritol ester of hydroabietic acid, both manufactured by Hercules Chemical Company; Nevtac 100 and Nevtac 80. synthetic polyterpene resins manufactured by Neville Chemical Company, Wingtack 86, a modified synthetic polyterpene resin manufactured by Goodyear Chemical Company, and Arakawa KE 311, a rosin ester manufactured by Arakawa Chemical Company.
Plasticizers are optionally, and preferably, added to the phase change ink carrier to increase flexibility and lower melt viscosity. Particularly suitable plasticizers include dioctyl phthalate, diundecyl phthalate, alkylbenzyl phthalate (Santicizer 278) and triphenyl phosphate, all manufactured by Monsanto Chemical Company; tributoxyethyl phosphate (KP-140) manufactured by FMC Corporation; dicyclohexyl phthalate (Morflex 150) manufactured by Morflex Chemical Company Inc.; and trioctyl trimellitate, manufactured by Kodak.
Other materials may be added to the phase change ink carrier composition. In a typical phase change ink chemical composition, antioxidants are added for preventing discoloration of the carrier composition. The preferred antioxidant materials include Irganox 1010 manufactured by Ciba Geigy; and Naugard 76, Naugard 512, and Naugard 524 manufactured by Uniroyal Chemical Company; the most preferred antioxidant being Naugard 524.
A particularly suitable phase change ink carrier composition comprises a tetra-amide and a mono-amide compound, a tackifier, a plasticizer, and a viscosity modifying agent. The preferred compositional ranges of this phase change ink carrier composition are as follows: from about 10 to 50 weight percent of a tetraamide compound, from about 30 to 80 weight percent of a mono-amide compound, from about 0 to 25 weight percent of a tackifier, from about 0 to 25 weight percent of a plasticizer, and from about 0 to 10 weight percent of a viscosity modifying agent.
Preferred phase change inks exhibit a high level of lightness, chroma, and rectilinear light transmissivity when utilized in a thin film of substantially uniform thickness, so that color images can be conveyed using overhead projection techniques. Another preferred property of the ink carrier is the ability to be reoriented into a thin film after printing without cracking or transferring to the rollers typically used for reorientation.
A phase change ink printed substrate is typically produced in a drop-on-demand ink jet printer. The phase change ink is applied to at least one surface of the substrate in the form of a predetermined pattern of solidified drops. Upon impacting the substrate surface, the ink drops, which are essentially spherical in flight, wet the substrate, undergo a liquid-to-solid phase change, and adhere to the substrate. Each drop on the substrate surface is non-uniform in thickness and transmits light in a non-rectilinear path.
The pattern of solidified phase change ink drops can, however, be reoriented to produce a light-transmissive phase change ink film on the substrate which has a high degree of lightness and chroma, when measured with a transmission spectrophotometer, and which transmits light in a substantially rectilinear path. The reorientation step involves the controlled formation of a phase change ink layer of a substantially uniform thickness. After reorientation, the layer of light-transmissive ink will transmit light in a substantially rectilinear path. If the substrate on which the ink is applied is also light transmissive, a projected image having clearly visible intense colors can be formed when a beam of light is projected through the reoriented printed substrate.
While not limited to any theory the mechanism proposed for the unexpected results shown herein is that flocculation induced by the water soluble polymer occurs with decreased force between coalesced particles. Due to the more open and less dense packing of the floc, an open structure is formed which is probably not as close packed as the structure which would form in the absence of flocculation. As evaporation continues the networks emerge from the structure of the floc. Upon further evaporation the surface of the floc network becomes exposed and capillary forces arise. The result of the capillary forces is that water surfaces of negative curvature occur in the interstices between particles. These forces arise partly because the solid/vapor interface has a higher energy than that of the solid/liquid interface. The liquid therefore tends to wet the solid. As the liquid covers the solid, a tensile stress appears on the liquid. Due to conservation this stress must be compensated by a compressive stress that shrinks the network forming islands and large pores.
The receptor layer is applied to the support as a coating suspension in a solvent. The most preferred solvent is water. The coating suspension comprises inorganic particulate material, a water soluble polymer and a water insoluble polymer. After application of the coating suspension onto the support the solvent is removed yielding a solid receptive layer comprising inorganic particulate matter, water soluble polymer and water insoluble polymer.
Once solutions are coated on the support, the aggregation process becomes prevalent as the coating dries. The liquid solution evolves into an irregular surface with a wide range of shapes and tortuous patterns depending upon both the drying rate and the initial concentration of the coating solutions. At very low drying rates a porous film appears to be uniform but with numerous cracks. At drying rates between 150 and 800 mg H2O/min. sq. dm. the film evolves into a sequence of rounded small islands separated by pores. As the drying rate increases further, the islands become larger. Measurements of the island size have been measured by using scaled electronmicrographs. At drying rates between 150 and 800 mg H2O/min sq. dm. the island size is optimized. Most preferred is a drying rate of between 200 and 500 mg H2O/min sq. dm.
This preferred structure can best be described by using scaled electronmicrographs. The island size is determined as the diameter of a circle having the same projected surface area as the island. In this way, the optimum island size has been determined to have a size of no more than 15 xcexcm diameter. More preferably, the island size is no more than 10 xcexcm. It is most preferred that the island be at least 1 xcexcm. The pores can be best described by taking cross sections in electronmicrographs and measuring both the asperity, or depth of the pore (Y), and the extent to which the pore wall is recessed from the inner edge of the pore opening (X). The angle defined by the complement of the arctan of Y/X ((arctan(Y/X)/pixc3x97180)xe2x88x9290) is preferred to be less than xe2x88x9220 degrees and more preferably less than xe2x88x9235 deg and most preferred to be less than xe2x88x9250 deg. Cross section electronmicrographs of the media described here overprinted with phase change ink shows penetration of the ink into these pores and a mechanical interlocking at the points of pore overhang.
The island size is determined as the diameter of a circle having the same surface area as the island. The optimum island size has been determined to have a size of no more than 15 xcexcm. More preferably, the island size is no more than 10 xcexcm. It is most preferred that the island size be at least 1 xcexcm.
Another dimension that describes the surface geometry in the direction perpendicular to the surface is R(z) the average distance between peaks and valleys which is a measure of the unevenness of the surface. This is the average distance between peaks and valleys which is a measure of the unevenness or asperity of the surface. Coated surfaces produced at moderate drying rates, that is when the small islands (less than 10 microns) are prevalent, have asperity (R(z)) values of at least 5.5 xcexcm and no more than 6.2 xcexcm. More preferably the asparity at least 5.5 xcexcm and no more than 6.0 xcexcm. In general, increased solution concentrations will lead to surfaces that are very irregular in size with high R(z) values.
The coating weight is measured gravimetrically. The sample is cut into a 10 cmxc3x9710 cm square and weighed on a calibrated analytical balance to the nearest 0.1 mgm. The cut sample is then immersed into acetone, or another suitable solvent, to soften and lift the coating as a free membrane. Any strongly adhered coating is removed with an acetone soaked wipe. The sample is then dried and reweighed to calculate the coating weight in mgm/sqdm by difference.
Tape test density is a quantitative measurement indicating the propensity of the phase change ink to remain adhered to the media under conditions of peel or delamination. The tape test is performed by adhering, using a 10 lb. roller weight, at least 10 cm of 3M Scotch Type 810 Magic Tape (19 mm wide) to cover all of a strip of a 5 cmxc3x975 cm square, maximum black density (Tektronix 016-1307-00 black wax) single layer wax ink crosshatched pattern (with 5 mm spaced 0.2 mm lines without ink) printed on the media using a Tektronix Phaser 340 in the paper mode at 300xc3x97600 dpi, (monochrome) leaving approximately 1 cm of tape unattached. By grasping the unattached tape tag, the tape is pulled off of the media and printed area in one single rapid motion. The density of the peeled (Tp) and the original inked (To) areas on the media are measured using a Macbeth TR927 densitometer zeroed with the clear filter and using the xe2x80x9cdensityxe2x80x9d selection, taking care to center the Macbeth spot in a single 5 mmxc3x975 mm crosshatched square. The tape test density is the loss of transmittance according to the following formula:   TT  =                    (                  100          -                      %                                      xe2x80x83                                    Tp                          )                    (                  100          -                      %                                      xe2x80x83                                    To                          )              xc3x97    100
where TT is relative tape test density;
Tp is % transmittance of the area after the tape is peeled off; and
To is % transmittance of the original inked area.
A higher tape test density is preferred since this indicates a smaller percentage of phase change ink removal. No removal of phase change ink would be indicated by a tape test density of 100. Complete removal of the phase change ink would be indicated by a tape test density of 0. Tape test values are typically reproducible to a standard deviation of no larger than 5%.
Impact represents a measure of the adhesion of the phase change ink under conditions of rapid delamination with higher numbers being preferred. Impact is measured by a Gardner Impact Tester (Cat No. 1G1121) from BYK Gardner, Silver Spring, Md. The tester is modified by placing a rubber stopper in the drilled out anvil to a position slightly above being flush with the top of the anvil. This is done so as to avoid gross distortions of the PET base film upon impact by the hammer. The weight used to deliver the hammer blow is the 125 gm weight available from BYK Gardner. A specially modified Tektronix Phaser 340 is used to deliver in one media pass a double layer of black ink uniformly to a 10 cmxc3x9719 cm area and after waiting for at least five minutes for the wax layer to come to room temperature, impacts are delivered from a height of 10 cm to each of four spots on a line parallel to the leading edge of the printed sheet on the side opposite the wax. One impact is delivered in the first spot, two in the second in succession, and so on up to a maximum of four impacts in the fourth spot. After impacting, Scotch Magic(TM) Tape (type 810) form 3M Company, St. Paul Minn. is applied over the impacted spots and slowly removed to lift any dislodged ink. The sample is then rated on a scale of 0 to 4 depending on the number of impacts required to dislodge ink from the impacted area. The following definition of grades were used:
The judgment of how much ink removal is considered xe2x80x9cvery littlexe2x80x9d is made by a comparison to a region which has not been impacted but has had the tape applied and removed.
To remove aging factors from consideration, the tape test densities reported herein are for fresh printings on four week old coatings.
The scratch resistance of coated media is measured by the use of the ANSI PH1.37-1977(R1989) method for determination of the dry scratch resistance of photographic film. The device used is described in the ANSI IT9.14-1992 method for wet scratch resistance. Brass weights up to 900 g. in the continuous loading mode are used to bear on a spherical sapphire stylus of 0.38 mm radius of curvature, allowing an estimated maximum loading of 300 kgm/cm2. Since the stylus is a constant, the results can be reported in gram mass required to break through the coating to the surface of the base polymer. Scratch data is typically accurate to within approximately 50 gms. The reported scratch resistance is for samples measured four weeks after coating.
Total haze, clarity and transmission of the coated media was measured with a Gardner Hazegard Plus System calibrated with clarity standards, zero calibration standards and to 1, 5, 10, 20 and 30% haze NIST standards (standard deviation 0.02) on 35 mm wide strips held 1.2 cm from the transmission entrance on the flat surface of a quartz cell. The reported haze is for four week old coatings at ambient conditions. Clarity is reported as percent transmittance.

Structured media for phase change ink printing


The present invention concerns a frame mattress comprising a frame (1) with a spring inlay (3) surrounded by the frame, and a material (2) over the spring inlay, together with a reversible mattress (5), arranged for abutting the material (2), and a cover (7) enveloping the reversible mattress (5) and at least partly the frame (1), characterised in that the material (2) is at least partly detachable and that the spring inlay (3), constituting a principally form stable unit, is reversibly arranged in the frame (1).

Beds and mattresses are an important part of our everyday life. Their main function is to provide each individual a good rest and sleep. It is therefore of utmost importance that they are constructed in such a way that each individuals' rest in bed is optimal throughout the total resting period. In order to achieve this, the construction of the bed must be such that a correct resting position and good pressure-relief for the whole body is achieved. The spinal column and the joints should rest in their natural positions in order that the muscles are strained as little as possible, and such that the blood circulation throughout the body becomes optimal. If the body is not provided with sufficient support during rest, new positions are often assumed to avoid stiffness and pins and needles (numbness) in the arms and legs. By repeated change of positions, the quality of sleep is reduced and the person will not be sufficiently rested. In the worst case scenario, insufficient support and poor sleeping position may give a stiff and sore neck, back ache, sore hip joints, numb arms and legs.
It has long been recommended by suppliers of ordinary reversible mattresses, placed on bed boards in ordinary beds, to turn the mattress at least once a year. The materials thereby obtain the time to recover on the used side, and the lifetime of the mattress is extended. Further, it is also recommended that the bed is cleaned in a god way to remove mite an especially excrements from mite which may give allergies. For good cleaning, vacuuming of the cover, bed, bed board and mattress is included, and not least washing the bed covers.
Frame mattresses are well known products in Scandinavia, and there are several different frame mattress models, amongst which the following may be mentioned:
DE 25 36 882 describes a standard frame mattress wherein a spring mattress is arranged on a plate over a frame and permanently combined with the plate. The frame does not contain a spring inlay and the spring mattress is not detachable or reversible, but the mattress cover is detachably attached to the frame. However, the patent does not describe a mattress which may be turned when the mattress cover is removed because the mattress springs are fastened to the base plate which is placed on top of the frame.
The frame mattress described in Norwegian patent no. 307641 is considered to constitute the closest prior art. This frame mattress is comprised of a frame wherein a spring inlay is fastened in a frame and covered with a material fastened to the frame, and a reversible mattress arranged for abutting the material, and wherein a cover is detachably mounted over the mattress and partly around the frame. In NO 307641, one was able to produce a frame mattress wherein the removal of the cover and the turning of the mattress, constituting the upper part of the frame mattress, was possible.
The present invention distinguishes itself from the frame mattress described in NO 307641 on several accounts and will be described in greater detail below.
The present invention solves the above mentioned problems regarding a high level of resting comfort while simultaneously achieving increased lifetime of the product, which furthermore may easily be maintained and completely cleaned.
More specifically, the present invention relates to a frame mattress comprising a frame (1) with a spring inlay (3) surrounded by the frame, and a material (2) over the spring inlay, together with a reversible mattress (5), arranged for abutting the material (2), and a cover (7) enveloping the reversible mattress (5) and at least partly the frame (1), wherein the material (2) is at least partly detachable and the spring inlay (3), constituting a principally form stable unit, is reversible arranged in the frame (1).
The supporting frame is constructed of a rigid and stable material, such as wood.
The materials (2′) and (2) are of a material such as Vliseline. The material (2′) is fastened by fastening means such as for example with hook and loop fasteners (e.g. Velcro) to the bottom of the frame (1), while the material (2) is mounted detachably to the top of the frame. The material (2) is at least partly releasable so that it may be folded aside or possibly removed entirely. The material is preferably fastened by fastening means (4) such as by hook and loop fasteners, snap fasteners, zippers etc., preferably hook and loop fasteners, with one part fastened to the frame (1), for example by stapling or gluing, while the facing part is fastened to the material (2), for example by a seam. Alternatively, the material or parts of the same may be fasted to the frame by for example hook and loop fasteners attached to the frame and material respectively. The material (2′) may be removed and alternatively replaced.
The reversible spring inlay (3) is constituted of low pocket-springs, i.e. individual springs sewn into textile bags. This system provides unique comfort as each individual spring reacts to body pressure independently of the adjacent springs. All the individual springs in the spring inlay may either be equally stressed or may preferably be divided into zones of different stress levels, such that zone partitioning is achieved, wherein different parts of the spring inlay have different stress-levels, achieving different bed firmness. The zones are for example adapted so that the protruding parts of the body such as the shoulders and hips, rest against softer springs than other parts of the body. In this way, less pressure is put on the shoulders and hips, and the body is provided with an even pressure load and good support at the same time. The spring inlay constitutes a principally form-stable unit which may be removed from the frame and turned in one or more parts. The spring inlay may for example consist of separate units for each comfort zone, such that a broken or worn zone may be replaced or changed separately. This also enables the bed to be adapted to the user individually by altering the length and firmness of the zones, for example. The pocket springs are in bags adhered to each other by being glued together at each point of contact, for example by melting glue. The spring inlay(s) may be of pocket springs or other types of springs known in the art.
The reversible mattress (5) is an ordinary mattress as such, comprising a spring core (3′), padding (6), side edges enveloped in a mattress cover. The spring core (3′) may consist of traditionally employed spring types such as Bonell-springs, LFK-springs and Pocket-springs such as the spring core (3) above, independently chosen in relation to the same. In the padding and side edges (6), all known types of padding material may be used, such as fibres, foamed plastic and foamed rubber. The reversible mattress may of course also contain a zone division consisting of springs with different stiffness, possibly in separate units as described over.
The cover (7) is form adapted and mounted detachably over the entire construction so that it encompasses both the reversible mattress and at least partly the frame, and is attached by fastening means (4′), preferably by hook and loop fasteners to the frame (1). Preferably, one part of the hook and loop fastener is stapled to the underside of the frame, whereas the counterpart is sewn onto the cover.
The frame mattress according to the present invention will ensure that the bed may be cleaned thoroughly in a far better way than earlier, since the material (2) may also be removed from the supporting frame (1), and in that all the main components of the bed are replaceable. It is novel in relation to the prior art technique, that the material, may at least partly be disconnected from the frame. Preferably, the material is removed completely from the frame. When the material is removed from the supporting frame, the spring inlay may be removed and turned or replaced as mentioned. The lifetime of the spring inlay and thus also the lifetime of the bed, may be approximately doubled when the springs are allowed to recover on the side not facing up, and at the same time the inner part and the base of the frame may be cleaned when the spring inlay is removed. Any change in the needs/desires of the user with regard to the firmness of mattress/bed caused by, for example altered body weight, may be addressed by individual or complete replacement of the spring cores.
The frame mattress as described above according to the present invention, will possess a double-spring effect. The purpose of the bottom spring so as to increase the spring depth of the frame mattress, thereby ensuring that the heavier parts of the body enter sufficiently into the mattress, and in this manner reduce the counter pressure from the bed against the body. The result is increased resting comfort and that blood circulation is not hindered when resting. It should be pointed out that it is novel to use a spring inlay with zone division in the frame. It has long been known that ordinary reversible mattresses, which are placed on bed rests in ordinary beds, may have a zone division of firm or soft spring zones, but this type of zone division has not been contemplated or used as spring inlay, neither detached nor fastened to the frame of a frame mattress. Prior frame mattresses were made in a manner wherein the spring inlay in the supporting frame was fastened to the bottom of the frame.
Briefly summarised, the present invention differs from the prior art technique in that:                the material may be removed from the frame (1),        the spring inlay (3) in the frame (1) lies unattached and may be removed and turned,        the spring inlay (3) in the frame (1) may be zone divided with alternating stiff and soft springs,        the zones may be separate units.
The present frame mattress has the improved properties in relation to:                1) hygiene as the cover (7) and the materials (2 and 2′) in the frame all may be removed and washed. This also makes it possible to gain access, so that the mattress resting on the frame may be vacuumed as well as the spring inlay, and possibly be removed so that the bottom of the frame may also be cleaned. Thorough cleaning is especially important in view of contagious diseases and allergies;        2) resting comfort is increased as the spring inlay may have zone divisions of softer and firmer springs;        3) the lifetime of the product is increased considerably, maybe to the double, because both the mattress resting on the frame and the spring inlay may be turned, such that the sides that have been used may retract when they no longer face up towards the individual. Alternatively the mattress and/or spring inlay may be replaced separately; and        4) flexibility in the choice of mattress and spring inlay for the consumer who may thereby obtain a custom adapted frame mattress.