A process for refining and degumming edible oils by ultrafiltration which produces a permeate fraction with reduced phosphatide content and retentate with increased phosphatide content, and wherein the ultrafiltration membrane is composed of a polymerical polymer of a vinylidene difluoride monomer.

1. Field of the Invention
The invention relates to a process for refining and degumming edible, industrial and specialty oils by ultrafiltration, leading to a permeate fraction with reduced phosphatide content and a retentate with increased phosphatide content, wherein the ultrafiltration membrane is composed of a polymer or copolymer of a vinylidene difluoride monomer.
2. Background of the Related Technology
Crude vegetable, nuts and animal oils and fats are produced by a large variety of processes (J. M. Fils, The production of oils in Edible Oil Processing, eds. W. Hamm and R. J. Hamilton, Sheffield Academic Press, Sheffield, 2000) and extraction with an organic solvent such as hexane, is one of these processes. This extraction process utilizes an organic solvent, such as hexane, and produces a solution of crude oil and the organic solvent, which is commonly referred to as xe2x80x9cmiscella.xe2x80x9d
Another process involves pressing the oil-bearing material in, for example, a mechanical screw press. This leads to crude pressed oil and a press cake which still contains appreciable amounts of residual oil. It is common practice to recover this residual oil by extracting the press cake with solvent.
In known processes, crude oils typically are degummed, refined, bleached and deodorized to remove undesirable compounds including: free fatty acids (FFAs), phosphatides, particulate matter like meal residues, coloring materials like chlorophylls and xanthophylol, and miscellaneous non-saponifiable materials. For example, in processing soybean oils, the first step is degumming to remove the phosphatides for the production of lecithin. Water degumming is a conventional degumming method. When water is added to crude oil, most of the phosphatides in the oil are hydrated and become insoluble in oil. The hydrated gums are then separated from the oil by centrifugation. Next, the FFAs are reacted with sodium hydroxide to produce soaps, which are then removed along with residual phosphatides by centrifugation. Some pigments and destabilizing peroxides are then adsorbed by, for example, acid-activated bleaching clay; and finally, the oil is heated under high vacuum with steam sparging to strip trace amounts of FFAs, aldehydes and ketones, and other volatile compounds.
Considerable amounts of energy in the form of steam or electricity are required in these processes, and each step of the process of making edible oil only removes one or two types of undesirable components. If crude oil is not properly processed, treatment during the following steps will be more difficult and time and labor consuming. In addition to the energy costs, caustic refining, water washing and bleaching steps produce various streams such as high biological oxygen demand (BOD) acidic waste water and spent bleaching clay that either need to be treated or recovered due to economical or environmental reasons.
In conventional refining processes, free fatty acids, undesirable flavors, odor and color compounds, and other natural components like the phosphatides, must be removed from crude vegetable oils before they are used for food. Unfortunately, a xe2x80x9crefining lossxe2x80x9d 3-4 times greater than the free fatty acids content is often experienced, and considerable quantities of salable xe2x80x9cneutral oilxe2x80x9d is lost.
Processes for refining glyceride oils utilizing semi-permeable membranes have been disclosed in literature. U.S. Pat. Nos. 4,062,882 and 4,093,540 to A. K. Sen Gupta describe a process for refining a crude glyceride oil composition by passing a solution of this oil in an organic solvent under pressure over a semi-permeable membrane. In this process, the membrane retains the phosphatides present in the oil solution as a result of which the oil solution passing through the membrane shows a reduced phosphatide content. The membranes described in U.S. Pat. No. 4,093,540 are made of polyacrylnitrile. The membranes described in U.S. Pat. No. 4,062,882 are made of polyacrylonitrile, a polysulphone and a polyamide.
In U.S. Pat. No. 4,553,501 to Sen Gupta, a membrane filtration process is described that not only removes the phosphatides present in the crude triglyceride oil but also the free fatty acids present therein by the addition of a base to the miscella. In addition to the polyacrylonitrile, polysulphone, and polyamide membranes mentioned above, polyimide anisotropic membranes are also used for this purpose. Membranes made of these polymers are also described in PCT 00/42138 to Jirjis et al.
Polyimide membranes are also described in U.S. Pat. No. 4,414,157 to Iwama et al. U.S. Pat. No. 4,545,940 to Mutoh et al. describes a membrane used for the dewaxing of triglyceride oils that consists of a copolymer of ethylene and tetrafluoroethylene. In addition to waxes, phospholipids and free fatty acids were also retained by this membrane, but the disclosed flux is too low to be economic.
A subsequent paper (S. S. Kxc3x6seo{haeck over (g)}lu, J. T. Lawhon and E. W. Lusas, Journal American Oil Chemists"" Society, 67 (5), 315-322, 1990) on the suitability of a number of ultrafiltration membranes, reported that membranes made of polyamide were the least affected by hexane, but that a membrane made from a fluorinated polymer was deteriorated by hexane.
Accordingly, a need has arisen for refining and degumming oils in a process which has improved separation and which is more economical and more environmentally suitable than known methods.
In accordance with the present invention, a process for refining and degumming oils by ultrafiltration is provided that significantly improves the quality of the edible oils and lecithin products and is more economical and environmentally suitable than known methods. The inventive process contacts oil with an ultrafiltration membrane, wherein the ultrafiltration membrane comprises a polymer or copolymer of a vinylidene difluoride monomer, and separates the oil into a permeate fraction having a reduced phosphatide, color and free fatty acids content and a retentate fraction having an increased phosphatide content.
Accordingly, an object of the present invention is to provide ultrafiltration membranes that can be profitably used in the refining and degumming of solutions of oils in organic solvents by an ultrafiltration process.
It is a further object of the invention to provide membranes for the refining and degumming by ultrafiltration of pressed oils, conducted in the absence of solvent.
A further object of the invention is to provide edible oil products and lecithin products prepared by ultrafiltration which have significantly improved qualities over known edible oil products and lecithin products.
The ultrafiltration membranes according to the present invention (i.e., comprised of a polymer or copolymer of a vinylidene difluoride monomer): (1) are hexane-resistant, i.e., they retain their strength and do not swell in hexane so that they retain their permeability and selectivity, (2) withstand the pressure drop over the membrane during ultrafiltration; (3) have a good permeability for triglyceride oil and its solvents, which results in a relatively high flux through the membrane during the ultrafiltration process; (4) retain free fatty acids, coloring pigments and phosphatides from pressed oil and/or miscella and thus show a high selectivity, (5) do not unduly suffer from fouling, i.e., rinsing the membrane with solvent, permeate or miscella at regular (but not too frequent) intervals restores the membrane flux to a fully acceptable and constant level.
In the process of the present invention, xe2x80x9ccrude oilxe2x80x9d (substantially unrefined, unprocessed oil) is contacted with an ultrafiltration membrane. If the crude oil is combined with a solvent, either as a result of extracting the crude oil from vegetable products or from the addition of solvent to improve separation, it is referred to as xe2x80x9cmiscella.xe2x80x9d If crude oil is recovered from vegetable products using physical methods, such as pressing, expellers, expanders, and/or extruders, and the oil is substantially free of solvent, it is referred to herein as xe2x80x9cpressed oil.xe2x80x9d
The oil (from, for example, pressed oil) or oil and solvent which pass through the pores of the ultrafiltration membrane are referred to as xe2x80x9cpermeate.xe2x80x9d The phosphatides and oil which do not pass through the ultrafiltration membrane are referred to as xe2x80x9cretentate.xe2x80x9d The retentate stream is preferably further treated to produce a lecithin product.
In the preferred processes, solvent is added to the retentate fraction, and this is contacted with an ultrafiltration membrane, which separates this retentate fraction with added solvent into a secondary permeate stream and a secondary retentate stream. By controlling the ultrafiltration membrane area and by selectively contacting the retentate fraction with added solvent with additional ultrafiltration membranes, the amount of oil in the secondary retentate stream (consisting primarily of phosphatides) can be selectively controlled to yield, upon evaporation, a lecithin product having an oil content of about 3 wt % to about 40 wt % or a substantially oil-free lecithin powder product. In the edible oil industry, it is common practice to define the lecithin product by its percentage of acetone insoluble compounds (consisting primarily of phosphatides), and thus, a lecithin product having an oil content of about 3 wt % to about 40 wt % would have an acetone insoluble content of about 60 wt % to about 97 wt %.
The permeate streams are preferable further refined, processed or treated to produce a high quality edible oil product, referred to herein as xe2x80x9can edible oil productxe2x80x9d or xe2x80x9crefined oil.xe2x80x9d
An improved process for processing crude oil is provided by the present invention by employing a membrane composed of a polymer or copolymer comprising vinylidene difluoride monomers that is incorporated in an ultrafiltration module. Such a module may contain a number of tubular membranes mounted inside a shell in such a way that the miscella fed to the module is divided over the different tubes. The permeate then emerges in the space between the tubes inside the shell so that it can be collected. The flows through each tube are collected at the other end of the module and constitute the retentate. Other ultrafiltration modules, such as, for example, spiral wound modules also exist and fall within the scope of the present invention.
Good results in degumming miscella have been obtained by using a polyvinylidene difluoride (PVdF)-membrane according to the present invention with a molecular weight cut-off (MWCO) of 30,000 dalton to 200,000 dalton. Lower MWCO""s, as for example 9,000 dalton, can also be used, but they are only slightly more selective and their flux is lower. The preferred MWCO is about 5,000 to about 500,000 daltons. The most preferred MWCO is about 10,000 to about 250,000 dalton.
Using a membrane with a higher MWCO leads to a higher flux and thus to savings in the investments required for a given degumming capacity but can lead to a decrease in selectivity. However, it has been found that this decrease can be effectively counteracted by forming a small amount of soap in a pressed oil or miscella being processed by partially neutralising the free fatty acids present therein. Consequently, the membranes according to the invention can also profitably be used for degumming crude pressed oils.
When a miscella comprising solvent, triglyceride oil and phosphatides is fed to such an ultrafiltration module, its membrane will retain the phosphatides but allow the solvent and the triglyceride oil to pass through the membrane. Accordingly, the retentate will have a higher phosphatide content than the feed and the permeate will have a significantly lower phosphatide content than the feed. This means that the refined oil resulting from evaporating the solvent from this permeate and from bleaching the still residue can be physically refined to yield a high quality, fully refined edible oil.
If one considered a xe2x80x9cfiltration spectrumxe2x80x9d, the spectrum would include, on the low end for filtering low molecular weight components; nanofiltration, ultrafiltration, and microfiltration. Nanofiltration is generally suitable for filtering compounds having a molecular weight of about 200-8,000, ultrafiltration is generally suitable for filtering compounds having a molecular weight of about 4,000-500,000, and microfiltration is generally suitable for filtering compounds having a molecular weight of about 250,000-1,000,000. As used in this patent application, the term xe2x80x9cultrafiltrationxe2x80x9d is intended to include the entire range of nanofiltration, ultrafiltration, and microfiltration.
The ultrafiltration mode in the process according to the present invention is preferably a cross-flow filtration. This means that the miscella is pumped along the ultrafiltration membrane and that only a fraction of the solvent and oil present in the miscella permeates through the membrane per pass through the membrane tube. Accordingly, the retentate can be recycled to the feed of the module and/or it can be fed to a second and/or subsequent modules to attain a higher phosphatide concentration in the retentate (and thus a higher yield of degummed oil).
Especially in the production of xe2x80x9cspecialty oilsxe2x80x9d and/or xe2x80x9cfunctional oilsxe2x80x9d, for example, fish oil or borage oil, the conventionally known processes for refining and degumming the oil involve heating and/or the addition of chemicals which may alter the stability of the edible oil product. It is believed that the specialty oils and functional oils contain an increased level of double bonds which, upon heating or chemical addition (as in conventionally known processes), may decompose or form polymers, altering the stability of the edible oil product. It is believed that other crude oils also contain double bonds (though at a significantly reduced level) and these double bonds are similarly altered during heating or upon the addition of chemicals in the conventionally known processes. A key feature of the present invention is the production of an edible oil product accomplished without heating and addition of chemicals as is done in the conventionally known processes, and thus, the present invention maintains the oil in its naturally occurring stable chemical composition and structure.
The oil produced from the permeate fraction may be slightly off-color, and bleaching the oil with an adsorbent such as clay, activated clay, activated carbon and bone black, may be required to produce an acceptable color oil.
The oil produced from the permeate fraction may be slightly off-odor, and a deodorizing step may be required to produce an oil having an acceptable odor.
In order to obtain a substantially oil-free retentate, it is preferred to dilute concentrated retentate with fresh solvent. This fresh solvent reduces the retentate viscosity and also compensates for the preferential permeation if any, of the solvent through the membrane. If there is a preferential solvent flow through the membrane, the Oil Concentration Factor (OCF) will be markedly lower than the Volumetric Concentration Factor (VCF). Then the oil concentration in the feed will be higher than its concentration in the permeate and, for mass balance reasons, the oil concentration in the retentate will be even higher, adding fresh solvent to the retentate will redress this situation.
Diluting the retentate with fresh solvent and its subsequent concentration by ultrafiltration will thus allow a substantially oil-free solution of phosphatides to be obtained. A substantially oil-free lecithin powder product can be produced from this solution by evaporating the solvent, for instance in a spray tower. Conventional oil-free lecithin powder is normally produced by de-oiling conventional standard lecithin, using either acetone or a liquefied hydrocarbon, such as propane. In conventional processes, this de-oiling constitutes a separate process step, and thus makes de-oiled lecithin an expensive product. Producing a substantially oil-free lecithin powder product according to the present invention is thus more economical than the conventional process.
Lecithin products can be produced by the process according to the present invention by controlling the oil content in a secondary retentate stream, i.e., the retentate stream produced upon contacting the retentate fraction with added solvent with an ultrafiltration membrane. In a preferred embodiment, the secondary retentate stream, having a concentrated phosphatide content, is processed to either a substantially oil-free lecithin powder product or a lecithin product (having an acetone insoluble content of about 60 wt % to about 97 wt %) without hydration (addition of water) so as to keep the phosphatides in their naturally occurring chemical composition and structure.
In the production of lecithin products by conventional processes, the phosphatides are hydrated (treated with water), and miscibility and density is used to separate the hydrated phosphatide and the oil in a centrifuge separation. Then, the hydrated phosphatide is dried to form a lecithin product. It is believed that the conventional lecithin product has a significant shortcoming in that the hydration process and subsequent drying alters the chemical composition and/or structure of the naturally occurring phosphatides. A key feature of the present invention is the production of a substantially oil-free lecithin powder product and/or a lecithin product (having an acetone insoluble content of about 60 wt % to about 97 wt %) accomplished without a hydration step and subsequent drying step, and thus, maintaining the phosphatides in their naturally occurring chemical composition and structure.
In a somewhat less preferred embodiment, the solvent is removed from the secondary retentate stream by evaporation and the evaporation residue is treated with conventionally known processes such as water degumming, acid degumming and acid refining, such that a gum phase is formed that can be separated from the oil phase by centrifuge and then dried conventionally, for instance in a wiped film evaporator. This less preferred embodiment of the invention produces a conventional, standard quality lecithin which can be sold into existing markets. The oil phase resulting from the centrifugal separation can be recycled into the process, i.e., added to the oil prior to the oil contacting the ultrafiltration membrane, or, if a purge is found to be needed, processed by conventional alkali refining, acid degumming or acid refining processes.
The process according to the invention can also be used for pressed oils, i.e., oils that do not contain solvent. Therefore, the process according to the present invention is particularly suited for plants that produce both pressed oil and extraction oil since the latter arises in miscella form. Then, the pressed oil is subjected to the ultrafiltration process until the retentate has become too viscous and the permeate flux has become unacceptably low, after which the retentate may be mixed with the miscella resulting from the extraction process. The permeate obtained during the press oil filtration can be physically refined after having been bleached to yield a fully refined, high quality oil. Similarly, the permeate obtained during the miscella ultrafiltration can be physically refined after its solvent has been evaporated.
In using membranes to separate the phosphatides from oil, the oil (triglycerides) and phosphatides may have similar molecular weights, making them difficult to separate with membranes. Phosphatides have both hydrophilic and hydrophobic ends, and thus, in non-aqueous environments (i.e., upon addition of a solvent) they form reverse micelles with globular structures. The micelles formed have a significantly increased molecular weight, thus improving membrane separation. A key feature of the present invention is that it allows ultrafiltration of pressed oil without the addition of solvent, such that the conventionally known phosphatide micelles are not formed.
The membranes used when degumming pressed oils according to the process of the present invention preferably have a rather high MWCO so that the membranes exhibit an increased flux. This increased flux is desirable since it allows more viscous products such as triglyceride oils to be profitably processed. On the other hand, the high MWCO may decrease the selectivity of the ultrafiltration process and cause some phosphatides to permeate through the membrane. According to one embodiment of the present invention, this decrease in selectivity can be effectively counteracted by adding a small amount of soap to the pressed oil being subjected to the ultrafiltration treatment. According to the invention, the soap can also be formed in situ by the addition of a base, such as a small amount of an hydroxide, such as caustic soda, or similar base, such as for instance a soluble silicate, such as sodium metasilicate. The amount of base should preferably be less than the equivalent amount of free fatty acids present.
The exact role of the soap is not clear, but it is possible that the soap serves to incorporate the phosphatide into a globular structure, somewhat similar to the micelles formed when solvent is added to crude oil, and effectively increases the size of the phosphatides, such that the phosphatides are retained by the membrane. Soaps are not found in the permeate, so that this can be physically refined without subjecting it to a soap removal treatment. The soaps in the retentate may require a soap removal treatment because of excessive foaming during subsequent retentate treatment.
It has also been found that the addition of surfactants serves to significantly improve the ultrafiltration of pressed oils. It has further been found that polar solvents, such as alcohols, for example, methanol, ethanol, and isopropyl alcohol, and water, significantly improve the ultrafiltration of pressed oils. While the exact role of surfactants and polar solvents is not known, it is believed that the addition of surfactants and/or the addition of polar solvents serve to incorporate the phosphatides into a globular structure, somewhat similar to micelles, which increases the effective molecular weight of the phosphatides, such that the ultrafiltration membrane provides suitable separation of the phosphatides and oil from pressed oils without the addition of solvents such as hexane.
It is not uncommon that membranes as delivered by their manufacturers are kept moist by water or aqueous glycerol. Then, the membrane is preferably conditioned beforehand by exposing it to solvents of decreasing polarity in a way that is known to those skilled in the art. Suitable solvents are, for example, an alcohol, such as isopropanol, to dissolve and remove the water and glycerol, and then hexane to remove the isopropanol. In this context, an intermediate rinsing with a mixture of isopropanol and hexane has been found to be quite effective.
It is preferable to subject the miscella or the pressed oil to a pre-filtration process before contacting with the ultrafiltration membrane. This pre-filtration process should remove meal fines and other particulate matter and thereby protect the ultrafiltration membrane against fouling. For this pre-filtration process, conventionally known units used to treat crude oil or miscella destined for the isolation of brilliant lecithin have been found to be fully adequate. The resulting filter cake can easily be disposed of via the meal and, if it contains solvent, by feeding it to a meal desolventising unit.
The crude oil may be at least partially degummed by conventional processes prior to contacting the oil with an ultrafiltration membrane. This increases the flux rate and allows fewer membrane modules to be used. Also, this lessens the frequency at which the membranes must be rinsed.
For capacity reasons, several ultrafiltration modules may be required in an industrial environment. These can be in parallel or in sequence, and a set of parallel modules can also be in sequence with a subsequent set of parallel modules. The size and number of modules in each set and the flow configuration is dependent upon the degrees of concentration achieved, the permeate fluxes attained through the membrane, and module cost. The most cost effective installation is preferably designed by mathematical modelling.
The temperature of the pressed oil or miscella during the ultrafiltration according to the present invention has been found not to be critical. If a miscella is processed, its temperature is preferably below the boiling point of the solvent for safety reasons, but higher temperatures also fall within the scope of the present invention. If a pressed oil is subjected to ultrafiltration according to the invention, its temperature may be raised since this reduces the viscosity of the oil, and thus its flux through the membrane. On the other hand, an increase in temperature may also affect the permeability and selectivity of the membrane. Accordingly, membrane properties should be determined experimentally and the results can then be used in arriving at an optimal situation.
Experiments should also be conducted to investigate the effect of pressure and linear flow rate on the flux through the membrane. In general, a higher pressure will lead to a higher flux, but it may also accelerate membrane fouling, and thus necessitate more frequent cleaning. In addition, a higher pressure may make cleaning the membrane more difficult in that it takes longer to re-establish the acceptable level of flux.
When a tubular membrane is used in the process according to the invention, cleaning by back flush is generally not possible. In that instance, rinsing the membrane with solvent by switching from retentate to solvent has been found to be the most effective way of cleaning the membrane. Switching to miscella is also acceptable, but is generally less effective than using fresh solvent. The use of permeate as rinsing medium has been found to be quite effective and may in practice be the most cost effective medium.

Degumming of edible oils by ultrafiltration


The present invention relates to a cleaning wipe which is a water insoluble substrate impregnated with a cleaning composition containing a cellulosic polymer.

The present invention relates to a dishwashing cleaning wipe which is single or multi layer fabric substrate which has been impregnated with a liquid cleaning composition.
The patent literature describes numerous wipes for both body cleaning and cleaning of hard surfaces but none describe wipes for cleaning dishware, flatware, pots and pans. U.S. Pat. Nos. 5,980,931, 6,063,397 and 6,074,655 teach a substantially dry disposable personal cleansing product useful for both cleansing and conditioning the skin and hair. U.S. Pat. No. 6,060,149 teaches a disposable wiping article having a substrate comprising multiple layers.
U.S. Pat. Nos. 5,756,612; 5,763,332; 5,908,707; 5,914,177; 5,980,922 and 6,168,852 teach cleaning compositions which are inverse emulsions.
U.S. Pat. Nos. 6,183,315 and 6,183,763 teach cleaning compositions containing a proton donating agent and having an acidic pH. U.S. Pat. Nos. 5,863,663; 5,952,043; 6,063,746 and 6,121,165 teaches cleaning compositions which are oil in water emulsions.
A single use cleaning wipe for dishwashing application comprises a water insoluble substrate, impregnated with a cleaning composition containing at least one surfactant, a cellulosic polymer and water.
The liquid cleaning compositions of this invention are not an emulsion and do not contain potassium sorbate, a polysaccharide polymer, a polycarboxylate polymer, polyvinyl alcohol polymer, polyvinylpyrrolidone polymer or methyl vinyl ether polymer.
The present invention relates to a cleaning wipe for dishware, flatware, pots and pans which comprises approximately by weight:
(a) 5% to 80% of a cleaning composition which comprises approximately by weight:
(i) 0.5% to 12% of a water soluble cellulosic polymer selected from the group consisting of methyl cellulose and hydroxypropyl methyl cellulose and mixtures thereof;
(ii) 15% to 50% of at least one surfactant selected from the group consisting of alkali metal salts of a fatty acids, ethoxylated nonionic surfactants, amine oxide surfactants, alkyl polyglucoside surfactants, zwitterionic surfactants, anionic surfactants and C12-C14 fatty acid monoalkanol amides and mixtures thereof;
(iii) 5 to 50%, more preferably 8% to 40% of at least one solubilizing agent;
(iv) 0 to 0.5%, more preferably 0.05% to 0.25%, of an antibacterial agent;
(v) 0 to 6%, more preferably 0.05% to 3% of a perfume; and
(vi) the balance being water; and
(b) 20% to 95% of a water insoluble substrate, wherein said water insoluble substrate comprises a top layer of coarse fibers, an absorbent center layer which is cellulosic paper and a bottom layer of fine fibers, wherein the layers are bonded together and the center layer is impregnated with said cleaning composition.
The anionic surfactants which may be used in the detergent film of this invention are water soluble and include the sodium, potassium, ammonium and ethanolammonium salts of C8-C18 alkyl sulfates such as lauryl sulfate, myristyl sulfate and the like; linear C8-C16 alkyl benzene sulfonates; C10-C20 paraffin sulfonates; alpha olefin sulfonates containing about 10-24 carbon atoms; C8-C18 alkyl sulfoacetates; C8-C18 alkyl sulfosuccinate esters; C8-C18 acyl isethionates; and C8-C18 acyl taurates. Preferred anionic surfactants are the water soluble C12-C16 alkyl sulfates, the C10-C15 alkylbenzene sulfonates, the C13-C17 paraffin sulfonates and the alpha C12-C18 olefin sulfonates.
The higher alkyl mononuclear aromatic sulfonates, such as the higher alkylbenzene sulfonates containing 9 to 18 or preferably 9 to 16 carbon atoms in the higher alkyl group in a straight or branched chain. A preferred alkylbenzene sulfonate is a linear alkylbenzene sulfonate having a higher content of 3-phenyl (or higher) isomers and a correspondingly lower content (well below 50%) of 2-phenyl (or lower) isomers, such as those sulfonates wherein the benzene ring is attached mostly at the 3 or higher (for example 4, 5, 6 or 7) position of the alkyl group and the content of the isomers in which the benzene ring is attached in the 2 or 1 position is correspondingly low. Preferred materials are set forth in U.S. Pat. No. 3,320,174, especially those in which the alkyls are of 10 to 13 carbon atoms.
Examples of suitable other sulfonated anionic detergents are the well known. The paraffin sulfonates may be monosulfonates or di-sulfonates and usually are mixtures thereof, obtained by sulfonating paraffins of 10 to 20 carbon atoms. Preferred paraffin sulfonates are those of C12-18 carbon atoms chains, and more preferably they are of C14-17 chains. Paraffin sulfonates that have the sulfonate group(s) distributed along the paraffin chain are described in U.S. Pat. Nos. 2,503,280; 2,507,088; 3,260,744; and 3,372,188; and also in German Patent 735,096. Such compounds may be made to specifications and desirably the content of paraffin sulfonates outside the C14-17 range will be minor and will be minimized, as will be any contents of di- or poly-sulfonates.
The C8-18 ethoxylated alkyl ether sulfate surfactants have the structure
xe2x80x83Rxe2x80x94(OCHCH2)nOSOxe2x88x923M+
wherein n is about 1 to about 22 more preferably 1 to 3 and R is an alkyl group having about 8 to about 18 carbon atoms, more preferably 12 to 15 and natural cuts, for example, C12-14 or C12-16 and M is an ammonium cation or a metal cation, most preferably sodium.
The ethoxylated alkyl ether sulfate may be made by sulfating the condensation product of ethylene oxide and C8-10 alkanol, and neutralizing the resultant product. The ethoxylated alkyl ether sulfates differ from one another in the number of carbon atoms in the alcohols and in the number of moles of ethylene oxide reacted with one mole of such alcohol. Preferred ethoxylated alkyl ether polyethenoxy sulfates contain 12 to 15 carbon atoms in the alcohols and in the alkyl groups thereof, e.g., sodium myristyl (3 EO) sulfate.
Ethoxylated C8-18 alkylphenyl ether sulfates containing from 2 to 6 moles of ethylene oxide in the molecule are also suitable for use in the invention compositions. These detergents can be prepared by reacting an alkyl phenol with 2 to 6 moles of ethylene oxide and sulfating and neutralizing the resultant ethoxylated alkylphenol.
The C12-C20 paraffin sulfonates may be monosulfonates or di-sulfonates and usually are mixtures thereof, obtained by sulfonating paraffins of 10 to 20 carbon atoms. Preferred paraffin sulfonates are those of C12-18 carbon atoms chains, and more preferably they are of C14-17 chains. Paraffin sulfonates that have the sulfonate group(s) distributed along the paraffin chain are described in U.S. Pat. Nos. 2,503,280; 2,507,088; 3,260,744 and 3,372,188 and also in German Patent 735,096. Such compounds may be made to specifications and desirably the content of paraffin sulfonates outside the C14-17 range will be minor and will be minimized, as will be any contents of di- or poly-sulfonates.
The present invention can also contain alpha olefin sulfonates, including long-chain alkene sulfonates, long-chain hydroxyalkane sulfonates or mixtures of alkene sulfonates and hydroxyalkane sulfonates. These alpha olefin sulfonate surfactants may be prepared in a known manner by the reaction of sulfur trioxide (SO3) with long-chain olefins containing 8 to 25, preferably 12 to 21 carbon atoms and having the formula RCHxe2x95x90CHR1 where R is a higher alkyl group of 6 to 23 carbons and R1 is an alkyl group of 1 to 17 carbons or hydrogen to form a mixture of sultones and alkene sulfonic acids which is then treated to convert the sultones to sulfonates. Preferred alpha olefin sulfonates contain from 14 to 16 carbon atoms in the R alkyl group and are obtained by sulfonating an a-olefin.
The long chain fatty acids are the higher aliphatic fatty acids having from about 8 to 22 carbon atoms, more preferably from about 10 to 20 carbon atoms, and especially preferably from about 12 to 18 carbon atoms, and especially preferably from 12 to 18 carbon atoms, inclusive of the carbon atom of the carboxyl group of the fatty acid. The aliphatic radical may be saturated or unsaturated and may be straight or branched. Straight chain saturated fatty acids are preferred. Mixtures of fatty acids may be used, such as those derived from natural sources, such as tallow fatty acid, coco fatty acid, soya fatty acid, mixtures of these acids, etc. Stearic acid and mixed fatty acids, e.g. stearic acid/palmitic acid, are preferred.
Thus, examples of the fatty acids include, for example, decanoic acid, dodecanoic acid, palmitic acid, myristic acid, stearic acid, behenic acid, oleic acid, eicosanoic acid, tallow fatty acid, coco fatty acid, soya fatty acid, mixtures of these acids, etc. Stearic acid and mixed fatty acids, e.g. stearic acid/palmitic acid, are preferred.
The nonionic surfactants which are used in the instant cleaning composition are selected from the group of an aliphatic ethoxylated nonionic surfactant and an aliphatic ethoxylated/propoxylated nonionic surfactant and mixtures thereof.
The water soluble aliphatic ethoxylated nonionic surfactants utilized in this invention are commercially well known and include the primary aliphatic alcohol ethoxylates and secondary aliphatic alcohol ethoxylates. The length of the polyethenoxy chain can be adjusted to achieve the desired balance between the hydrophobic and hydrophilic elements.
The nonionic surfactant class includes the condensation products of a higher alcohol (e.g., an alkanol containing about 8 to 16 carbon atoms in a straight or branched chain configuration) condensed with about 4 to 20 moles of ethylene oxide, for example, lauryl or myristyl alcohol condensed with about 16 moles of ethylene oxide (EO), tridecanol condensed with about 6 to 15 moles of EO, myristyl alcohol condensed with about 10 moles of EO per mole of myristyl alcohol, the condensation product of EO with a cut of coconut fatty alcohol containing a mixture of fatty alcohols with alkyl chains varying from 10 to about 14 carbon atoms in length and wherein the condensate contains either about 6 moles of EO per mole of total alcohol or about 9 moles of EO per mole of alcohol and tallow alcohol ethoxylates containing 6 EO to 11 EO per mole of alcohol.
A preferred group of the foregoing nonionic surfactants are the Neodol ethoxylates (Shell Co.), which are higher aliphatic, primary alcohol containing about 9-15 carbon atoms, such as C9-C11 alkanol condensed with 4 to 10 moles of ethylene oxide (Neodol 91-8 or Neodol 91-5), C12-13 alkanol condensed with 6.5 moles ethylene oxide (Neodol 23-6.5), C12-15 alkanol condensed with 12 moles ethylene oxide (Neodol 25-12), C14-15 alkanol condensed with 13 moles ethylene oxide (Neodol 45-13), and the like. Such ethoxamers have an HLB (hydrophobic lipophilic balance) value of about 8 to 15 and give good O/W emulsification, whereas ethoxamers with HLB values below 7 contain less than 4 ethyleneoxide groups and tend to be poor emulsifiers and poor detergents.
Additional satisfactory water soluble alcohol ethylene oxide condensates are the condensation products of a secondary aliphatic alcohol containing 8 to 18 carbon atoms in a straight or branched chain configuration condensed with 5 to 30 moles of ethylene oxide. Examples of commercially available nonionic detergents of the foregoing type are C11-C15 secondary alkanol condensed with either 9 EO (Tergitol 15-S-9) or 12 EO (Tergitol 15-S-12) marketed by Union Carbide.
One of the water soluble nonionic surfactants which can be utilized in this invention are an aliphatic ethoxylated/propoxylated nonionic surfactants which are depicted by the formula:
wherein R is a branched chain alkyl group having about 10 to about 16 carbon atoms, preferably an isotridecyl group and x and y are independently numbered from 1 to 20. A preferred ethoxylated/propoxylated nonionic surfactant is Plurafac(copyright) 300 manufactured by BASF.
The water-soluble zwitterionic surfactant, which can also be used provides good foaming properties and mildness. The zwitterionic surfactant is a water soluble betaine having the general formula:
wherein R1 is an alkyl group having 10 to 20 carbon atoms, preferably 12 to 16 carbon atoms, or the amido radical:
wherein R is an alkyl group having 9 to 19 carbon atoms and a is the integer 1 to 4; R2 and R3 are each alkyl groups having 1 to 3 carbons and preferably 1 carbon; R4 is an alkylene or hydroxyalkylene group having from 1 to 4 carbon atoms and, optionally, one hydroxyl group. Typical alkyldimethyl betaines include decyl dimethyl betaine or 2-(N-decyl-N,N-dimethyl-ammonia) acetate, coco dimethyl betaine or 2-(N-coco N, N-dimethylammonio) acetate, myristyl dimethyl betaine, palmityl dimethyl betaine, lauryl diemethyl betaine, cetyl dimethyl betaine, stearyl dimethyl betaine, etc. The amidobetaines similarly include cocoamidoethylbetaine, cocoamidopropyl betaine and the like. A preferred betaine is coco (C8-C18) amidopropyl dimethyl betaine.
Amine oxide semi-polar nonionic surfactants comprise compounds and mixtures of compounds having the formula:
wherein R1 is an alkyl, 2-hydroxyalkyl, 3-hydroxyalkyl, or 3-alkoxy-2-hydroxypropyl radical in which the alkyl and alkoxy, respectively, contain from 8 to 18 carbon atoms, R2 and R3 are each methyl, ethyl, propyl, isopropyl, 2-hydroxyethyl, 2-hydroxypropyl, or 3-hydroxypropyl, and n is from 0 to 10. Particularly preferred are amine oxides of the formula:
wherein R1 is a C12-16 alkyl and R2 and R3 are methyl or ethyl. The above ethylene oxide condensates, amides, and amine oxides are more fully described in U.S. Pat. No. 4,316,824 which is hereby incorporated herein by reference.
The alkyl polysaccharides surfactants, which can be used have a hydrophobic group containing from about 8 to about 20 carbon atoms, preferably from about 10 to about 16 carbon atoms, most preferably from about 12 to about 14 carbon atoms, and polysaccharide hydrophilic group containing from about 1.5 to about 10, preferably from about 1.5 to about 4, most preferably from about 1.6 to about 2.7 saccharide units (e.g., galactoside, glucoside, fructoside, glucosyl, fructosyl; and/or galactosyl units). Mixtures of saccharide moieties may be used in the alkyl polysaccharide surfactants. The number x indicates the number of saccharide units in a particular alkyl polysaccharide surfactant. For a particular alkyl polysaccharide molecule x can only assume integral values. In any physical sample of alkyl polysaccharide surfactants there will be in general molecules having different x values. The physical sample can be characterized by the average value of x and this average value can assume non-integral values. In this specification the values of x are to be understood to be average values. The hydrophobic group (R) can be attached at the 2-, 3-, or 4-positions rather than at the 1-position, (thus giving e.g. a glucosyl or galactosyl as opposed to a glucoside or galactoside). However, attachment through the 1-position, i.e., glucosides, galactoside, fructosides, etc., is preferred. In the preferred product the additional saccharide units are predominately attached to the previous saccharide unit""s 2-position. Attachment through the 3-, 4-, and 6-positions can also occur. Optionally and less desirably there can be a polyalkoxide chain joining the hydrophobic moiety (R) and the polysaccharide chain. The preferred alkoxide moiety is ethoxide.
Typical hydrophobic groups include alkyl groups, either saturated or unsaturated, branched or unbranched containing from about 8 to about 20, preferably from about 10 to about 18 carbon atoms. Preferably, the alkyl group is a straight chain saturated alkyl group. The alkyl group can contain up to 3 hydroxy groups and/or the polyalkoxide chain can contain up to about 30, preferably less than about 10, alkoxide moieties.
Suitable alkyl polysaccharides are decyl, dodecyl, tetradecyl, pentadecyl, hexadecyl, and octadecyl, di-, tri-, tetra-, penta-, and hexaglucosides, galactosides, lactosides, fructosides, fructosyls, lactosyls, glucosyls and/or galactosyls and mixtures thereof.
The alkyl monosaccharides are relatively less soluble in water than the higher alkyl polysaccharides. When used in admixture with alkyl polysaccharides, the alkyl monosaccharides are solubilized to some extent. The use of alkyl monosaccharides in admixture with alkyl polysaccharides is a preferred mode of carrying out the invention. Suitable mixtures include coconut alkyl, di-, tri-, tetra-, and pentaglucosides and tallow alkyl tetra-, penta-, and hexaglucosides.
The preferred alkyl polysaccharides are alkyl polyglucosides having the formula
R2O(CnH2nO)r(Z)x
wherein Z is derived from glucose, R is a hydrophobic group selected from the group consisting of alkyl, alkylphenyl, hydroxyalkylphenyl, and mixtures thereof in which said alkyl groups contain from about 10 to about 18, preferably from about 12 to about 14 carbon atoms; n is 2 or 3 preferably 2, r is from 0 to 10, preferable 0; and x is from 1.5 to 8, preferably from 1.5 to 4, most preferably from 1.6 to 2.7. To prepare these compounds a long chain alcohol (R2OH) can be reacted with glucose, in the presence of an acid catalyst to form the desired glucoside. Alternatively the alkyl polyglucosides can be prepared by a two step procedure in which a short chain alcohol (R1OH) can be reacted with glucose, in the presence of an acid catalyst to form the desired glucoside. Alternatively the alkyl polyglucosides can be prepared by a two step procedure in which a short chain alcohol (C1-6) is reacted with glucose or a polyglucoside (x=2 to 4) to yield a short chain alkyl glucoside (x=1 to 4) which can in turn be reacted with a longer chain alcohol (R2OH) to displace the short chain alcohol and obtain the desired alkyl polyglucoside. If this two step procedure is used, the short chain alkylglucosde content of the final alkyl polyglucoside material should be less than 50%, preferably less than 10%, more preferably less than about 5%, most preferably 0% of the alkyl polyglucoside.
The amount of unreacted alcohol (the free fatty alcohol content) in the desired alkyl polysaccharide surfactant is preferably less than about 2%, more preferably less than about 0.5% by weight of the total of the alkyl polysaccharide. For some uses it is desirable to have the alkyl monosaccharide content less than about 10%.
The used herein, xe2x80x9calkyl polysaccharide surfactantxe2x80x9d is intended to represent both the preferred glucose and galactose derived surfactants and the less preferred alkyl polysaccharide surfactants. Throughout this specification, xe2x80x9calkyl polyglucosidexe2x80x9d is used to include alkyl polyglycosides because the stereochemistry of the saccharide moiety is changed during the preparation reaction.
An especially preferred APG glycoside surfactant is APG 625 glycoside manufactured by the Henkel Corporation of Ambler, Pa. APG25 is a nonionic alkyl polyglycoside characterized by the formula:
xe2x80x83CnH2n+1O(C6H10O5)xH
wherein n=10 (2%); n=122 (65%); n=14 (21-28%); n=16 (4-8%) and n=18 (0.5%) and x (degree of polymerization)=1.6. APG 625 has: a pH of 6 to 10 (10% of APG 625 in distilled water); a specific gravity at 25xc2x0 C. of 1.1 g/ml; a density at 25xc2x0 C. of 9.1 lbs/gallon; a calculated HLB of 12.1 and a Brookfield viscosity at 35 C., 21 spindle, 5-10 RPM of 3,000 to 7,000 cps.
The cleaning composition can also contain a mixture of a C12-14 alkyl monoalkanol amide such as lauryl monoalkanol amide and a C12-14 alkyl dialkanol amide such as lauryl diethanol amide or coco diethanol amide.
As used herein and in the appended claims the term xe2x80x9cperfumexe2x80x9d is used in its ordinary sense to refer to and include any non-water soluble fragrant substance or mixture of substances including natural (i.e., obtained by extraction of flower, herb, blossom or plant), artificial (i.e., mixture of natural oils or oil constituents) and synthetically produced substance) odoriferous substances. Typically, perfumes are complex mixtures of blends of various organic compounds such as alcohols, aldehydes, ethers, aromatic compounds and varying amounts of essential oils (e.g., terpenes) such as from 0% to 80%, usually from 10% to 70% by weight, the essential oils themselves being volatile odoriferous compounds and also serving to dissolve the other components of the perfume.
In the present invention the precise composition of the perfume is of no particular consequence to cleaning performance so long as it meets the criteria of water immiscibility and having a pleasing odor. Naturally, of course, especially for cleaning compositions intended for use in the home, the perfume, as well as all other ingredients, should be cosmetically acceptable, i.e., non-toxic, hypoallergenic, etc.
The cleaning composition can contain at least one solubilizing agent selected from the group consisting of a C2-5 mono, dihydroxy or polyhydroxy alkanols such as ethanol, isopropanol, glycerol ethylene glycol, diethylene glycol, propylene glycol, and hexylene glycol and mixtures thereof, urea, and alkali metal cumene or xylene sulfonates such as sodium cumene sulfonate and sodium xylene sulfonate.
The cleaning composition of this invention may, if desired, also contain other components either to provide additional effect or to make the product more attractive to the consumer. The following are mentioned by way of example: Colors or dyes in amounts up to 0.5% by weight; pH adjusting agents, such as sulfuric acid or sodium hydroxide, can be used as needed.
Preservatives which can be used in the instant compositions at a concentration of 0.005 wt. % to 3 wt. %, more preferably 0.01 wt. % to 2.5 wt. % are: benzalkonium chloride; benzethonium chloride,5-bromo-5-nitro-1,3dioxane; 2-bromo-2-nitropropane-1,3-diol; alkyl trimethyl ammonium bromide; N-(hydroxymethyl)-N-(1,3-dihydroxy methyl-2,5-dioxo-4-imidaxolidinyl-Nxe2x80x2-(hydroxy methyl) urea; 1-3-dimethyol-5,5-dimethyl hydantoin; formaldehyde; iodopropynl butyl carbamata, butyl paraben; ethyl paraben; methyl paraben; propyl paraben, mixture of methyl isothiazolinone/methyl-chloroisothiazoline in a 1:3 wt. ratio; mixture of phenoxythanol/butyl paraben/methyl paraben/propylparaben; 2-phenoxyethanol; tris-hydroxyethyl-hexahydrotriazine; methylisothiazolinone; 5-chloro-2-methyl-4-isothiazolin-3-one; 1,2-dibromo-2,4-dicyanobutane; 1-(3-chloroalkyl)-3,5,7-triaza-azoniaadamantane chloride; and sodium benzoate. PH adjusting agents such as sulfuric acid or sodium hydroxide can be used as needed.
The cellulosic polymer which is used in the cleaning composition is selected from the group consisting of methyl cellulose and hydroxy propyl methyl cellulose Dow Chemical manufactures these cellulosic polymers under the tradename Methocel. The following chart set forth suitable Methocel polymer useful in the instant invention.
The cellulosic polymer acts to regulate and slow the release of the cleaning composition from the water insoluble substrate.
The cleaning composition is made by preparing aqueous surfactant solution and a aqueous polymeric solution of the cellulosic polymer at a 12 wt. % to 18 wt. % of the cellulosic polymer. The surfactant composition solution and the polymeric solution are mixed by simple mixing at room temperature in a 4:1 to 1:4 weight ratio to form the cleaning solution which is to impregnate the water insoluble substrate.
The bottom and top layers may have different textures and abrasiveness. Differing textures can result from the use of different combinations of materials or from the use of different manufacturing processes or a combination thereof. A dual texture substrate can be made to provide the advantage of a more abrasive side for cleaning difficult to remove soils. A softer side can be used for more delicate or less soiled surfaces. The substrate should not dissolve or break apart in water. It is the vehicle for delivering the cleaning composition to dishware, flatware, pots and pans. Use of the substrate enhances lathering, cleaning and grease removal.
A wide variety of materials can be used as the substrate. It should have sufficient wet strength, abrasivity, loft and porosity. Examples include, non woven substrates, wovens substrates, hydroentangled substrates and sponges.
Examples of suitable non woven water insoluable substrates include, 100% cellulose Wadding Grade 1804 from Little Rapids Corporation, 100% polypropylene needlepunch material NB 701-2.8xe2x80x94W/R from American Non-wovens Corporation, a blend of cellulosic and synthetic fibres-Hydraspun 8579 from Ahlstrom Fibre Composites, and and0% Viscose/30% PES Code 9881 from PGI Nonwovens Polymer Corp.
Another useful substrate is manufactured by Jacob Holm-Lidro Rough""n Soft. It is a composition material comprising a 65/35 viscose rayon/polyester hydroentangled spunlace layer with a hydroenlongated bonded polyeser scribbly layer.
Still another useful substrate is manufactured by Texel. It is a composite material manufactured from a top layer of coarse fiber 100% polypropylene needlepunch, a center layer of an absorbent cellulose core and a bottom layer of a fine fiber polyester layer needlepunched together. The polypropylene layer can range from 1.5 to 3.5 oz/sq. yd. The cellulose core is a didn""t we hear that the use of the word xe2x80x9ccrepexe2x80x9d brings problemsxe2x80x94or is that just saying xe2x80x9ccrepe paperxe2x80x9d and not xe2x80x9ccreped paperxe2x80x9d? paper layer ranging from 0.5 to 2 oz./sq. yd. The fine fiber polyester layer can range from 0.5 to 2 oz./sq. yd. At least 50 wt. % of the impregnated cleaning composition is contained within the cleaning cellulose core layer.
The product of the present invention comprising mutliple layers may be ultrasonically bonded with appropriate choice of materials after applying the coating of one or more of the layers. Alternatively layers may be bonded together by needlepunch, mechanical means such as sewing, thermal bonding, chemical bonding, or sonic bonding prior to impregnation.
The following examples illustrate liquid cleaning compositions of the described invention. Unless otherwise specified, all percentages are by weight. The exemplified compositions are illustrative only and do not limit the scope of the invention. Unless otherwise specified, the proportions in the examples and elsewhere in the specification are by weight.


The invention provides a treatment for edge surfaces and faces of metallized fiber structure framework plates for use in electric accumulators. The edge surfaces and faces, except for the starting portion of the current tapping tab, are mechanically, thermally or chemically freed of projecting metallized fiber ends and fiber bundles in order to avoid short circuits or soft shorts caused by dendrites penetrating the cell separator or by metallized fiber ends. The mechanical, thermal or chemical treatments can take place individually or in combination with one another.

The invention relates to fabricated porous metallized fiber structure framework plates for use as an electrode or recombination element (gas diffusion bodies) in electric accumulators, and to a process for manufacturing such plates.
Accumulators having a type of electrode made of a framework of metallized synthetic fibers, as well as different partial aspects or manufacturing steps therefor, are known from various patent publications:
German Patent Document DE-PS 40 04 106, for example, describes a nonwoven metallized synthetic-fiber electrode framework for battery electrodes, with an increased load capacity.
Processes for activation and chemical metallization of nonwoven and needle felt webs are disclosed in German Patent Documents DE-PS 36 31 055 and DE-PS 36 37 130.
German Patent Documents DE-PS 38 17 827, DE-PS 38 17 826 and DE-PS 40 10 811 disclose aqueous nickel hydroxide or cadmium oxide pastes for the vibration filling of foam and fiber structure electrode frameworks.
German Patent Document DE-PS 38 22 197 describes processes for continuous filling of fiber structure electrode frameworks, and for cleaning away excess paste from the electrode plate, preferably by means of brushes, after mechanical filling.
German Patent Document DE-PS 36 32 352 discloses a fiber structure electrode plate with a welded-on current tapping tab.
German Patent Document DE-PS 40 18 486 discloses a process for manufacturing fiber structure electrodes, in which the framework is calibrated before the filling, and is calibrated again afterward, by means of a whole-surface pressing-together.
German Patent Documents DE-PS 40 40 017 and DE-PS 41 03 546 respectively describe a process for filling fiber structure electrode frameworks for accumulators with an active-mass paste while simultaneously calibrating the framework; in the former, the framework is rolled during the filling operation, and in the latter, the plate is pressed during the filling operation.
Despite the intensive treatment of the topic which is of interest here and which is documented by the above-mentioned list (which is to serve only as an example, and is by no means complete), difficulties and inadequacies in fiber structure electrode plates which become apparent only during the operation of the cells, continue to occur. As a result of the cycle-dependent volume mainly of the positive electrodes and the separators, and the resulting displacement of the components with respect to one another due to charging and discharging, occasionally premature capacity losses of the accumulator will occur.
The manufacture of such fiber structure electrodes is based on a nonwoven made of synthetic fibers. According to experience, nonwovens and needle felts with starting porosities of from 45% to 96% with a fiber diameter of between 5 .mu.m and 40 .mu.m are particularly suitable for the manufacture of fiber structure electrodes and recombination elements with a metallic fiber structure. After chemical activation, wet-chemical metallizing and galvanic reinforcing of the metal coating, the pieces finished to this extent are cut to a useful size and the plates are provided with a current tapping tab on a portion of a dimensionally stable edge which is reinforced during the galvanizing and was left standing in areas. Before filling with the active mass, the fiber structure framework plates are calibrated in order to be able to manufacture electrode frameworks with a defined filling while the scattering is low.
During fabrication of the fiber structure framework plates, the fiber structure will fan out on the cut edges because of the separating, sawing or cutting. That is, the spatial fiber composite will be partly lost in the area of such cutting, etc., and individual fibers or fiber bundles may come to the surface already because of their inherent tension and may project from it more or less steeply. When the active mass is entered into the fiber structure framework by vibration filling, the fibers exposed in the cutting area are further relaxed because of the vibrations. By means of the vibrations and the active mass penetrating into the fiber structure, the fanning-out may be increased. A superficially adhering excess of active mass paste must then be mechanically removed, which also exacerbates the fanning-out of individual fibers from the fiber structure in the area of the cut edges. In this case, the ends of fibers which are not completely linked into the composite are occasionally torn out and may, under certain circumstances, even project from the electrode surface at a right angle.
Fiber structure framework plates of the type addressed here are used in the accumulator construction not only as positive or negative electrode plates (after the filling-in of the active mass), but also in the form of metallized fiber frameworks (not filled with an active mass) as a gas diffusion framework and recombination element on which the oxygen is reduced relatively rapidly. The gas diffusion frameworks should rest against the electrodes or against individual negative electrodes in a full-surface and electrically conductive manner. The recombination elements therefore do not require a current tapping tab. Also when fiber structure framework plates of this type are manufactured, individual metallized fibers may protrude from the flat side of the framework plate in a more or less steep fashion and can also not be pressed back permanently into the composite by means of a calibrating operation.
Such metallized fibers and fiber composites which are pulled up or spread out from the fiber composite would result in a certain failure rate of the cells, because of internal short circuits. For this reason, such interfering fibers are normally pushed back by means of another calibration after the filling and drying of the fiber structure electrodes and before the assembly to an accumulator. However, this technique represents another working step during which, because of a possible formation of dust as the result of the crushed dry active material, additional special workers' protection measures are necessary.
Despite the calibration of the (filled or unfilled) framework plates, afterwards individual fibers may still project from the flat side of the framework plate. During the combined mechanical stressing of the plate composite which occurs during the assembly of the different framework plates and separators to an accumulator, as a result of pressing directed transversely to the plates and a thrust directed in parallel to the layer construction, if unfavorable circumstances coincide, individual fibers may penetrate into the separators and may even penetrate through the thin separators to the opposite electrode plate. Moreover, mainly during the mounting of the current tapping tabs, stresses occur in the area of the starting portion of the current tapping tabs on the electrode plates, which promote such a piercing of individual fibers through the separators. In the dry condition of the freshly assembled cell, a possible subsequent short circuit can usually not yet be diagnosed or localized. However, after a few cycles during the formation, or more probably later in the accumulator operation, because of a constant volume change in the positives as the result of the charge and discharge operation or because of the expanding of the plate stack by the addition of electrolyte, a projecting fiber, at first hidden, may cause a failure of the cell because of a local short circuit. Even if a fiber itself may not have completely penetrated the separators after a certain number of cycles, needle-like, electrically conductive dendrites grow up from such local anomalies, and may penetrate the separators, leading to a short circuit.
It is an object of the invention to provide an improved fiber structure for framework plates which exhibits enhanced operational reliability, and eliminates or considerably reduces the danger of short circuits between electrode plates of different polarities due to superficially projecting, metallized fiber ends or fiber bundles and/or because of the formation of dendrites.
This object is achieved by the fiber structure framework plates according to the invention, in which the projecting fibers themselves are removed from the framework plates and/or their damaging influence is eliminated, by sealing the projecting fibers in an electrically insulating manner or embedding them into a mass. Surprisingly, it was found that such fiber structure framework plates can be treated by stress-intensive, mechanical, thermal or chemical process steps on their edge surfaces and faces, without any significant impairment of the fiber structure areas situated outside the treated edge surfaces and faces.
In conjunction with mechanical treatment of the edge surfaces and faces to eliminate projecting metallized fiber ends or fiber bundles, it is also particularly recommended that the otherwise interfering projecting fiber ends be integrated back into the framework composite already when the framework plates are cut to size, by a suitable selection of the cross-sectional shape of the cutting tool. This can be achieved by the use of chamfered cutting tools which are shaped similarly to those used in a punching process, move toward one another and perform the cutting to size from the two flat sides of the fixed framework.
Likewise, it is possible to cold-emboss or hot-emboss the edge surfaces and faces of the metallic framework without any lasting damage to its areas which are away from the edge surfaces and faces, in order to obtain bevels at the upper and lower edges of the framework (except at the starting portion of the current tapping tabs). Such bevels also prevent fibers from projecting at the framework edge, which later during accumulator operation could be preferred starting points for the growth of dendrites, with a subsequent separator perforation.
Also by applying a hot-melt-type adhesive or bonding agent to the edge surfaces or faces of the fiber framework (except for the starting portion of the current tapping tab), the metallic surfaces of fibers or fiber bundles projecting there can be electrically insulated, thereby effectively preventing them from creating inhomogeneities in the electric field and generating voltage peaks. By coating projecting fiber ends or fiber bundles with a polymer layer, for example, a bonding agent or a hot-melt-type adhesive, the exposed fiber tip is blunted and the fiber ends or fiber bundles are therefore deprived of their perforation force with respect to the separator. In this case, it was found to be advantageous to apply mechanical pressure to the edge surface or face (except at the current tapping tab), immediately after the coating with the adhesive or bonding agent, until the adhesive or the bonding agent is hardened or dried. In the process, after the application of the adhesive or bonding agent, the face or edge surface of the fiber structure framework plates can be moved under pressure in a rotating manner from one plate edge to the other.
Another aspect of the invention consists of locally heating the faces and edge surfaces (except at the current tapping tabs) to such an extent that the cores of the projecting fiber ends or fiber bundles will melt, and the molten plastic emerging from the metal covering will seal the fiber ends in the form of a molten bead. At the same time, to melt the fiber cores, it is recommended that pressure be applied on the edge surface or face of the framework (except at the starting portion of the current tapping tab) in order to integrate the projecting fiber ends or fiber bundles with the reduced stiffness back into the fiber framework composite. Also in this case, pressure can advantageously be applied on the edge surface and face of the framework, by a back-and-forth rotating or rolling movement of the whole framework on a firm base.
In an expedient further embodiment of the invention, the edge surfaces and faces of the fiber structure framework (except at the starting portion of the current tapping tab), can be subjected to a resistance welding. In the course of resistance welding fibers projecting from the framework edges, on the one hand, are deformed locally by the effect of pressure and temperature, so that they are integrated back into the fiber structure composite of the other fibers. However, on the other hand, simultaneously the edge of the fiber structure framework is permanently deformed as well as compressed.
Naturally, the above-mentioned processes for treating fiber structure framework plates of the above-mentioned type can be combined with one another. It is not absolutely necessary to use the different treatment methods simultaneously as in the above-mentioned example of the resistance welding, but these treatment methods may also be applied successively in a time-staggered manner. For example, the edge of the metallized fiber structure can be mechanically deformed in a first step in order to then be acted upon by a bonding agent or hot-melt-type adhesive for an additional protection against the growth of dendrites. Likewise, the edge can essentially already be freed of projecting fiber ends by a local heating, after which it can be coated in a second step with a bonding agent or hot-melt-type adhesive. It is particularly recommended, although not essential, to treat the plate edge before the filling with an active mass.
The advantages of the invention consist of two effects: On the one hand, as a result of the edge treatment of the metallized textile fiber structure frameworks, dimensional accuracy of the electrode plates or gas diffusion bodies to be built into the cell is improved. This results in a number of favorable effects in conjunction with a uniform pressure onto the electrode surfaces during the expansion and shrinkage processes while the accumulator is charged and discharged. Secondly, specifically in the case of cells with a negative mass which has the strong tendency to precipitate dendrites, such as cadmium or zinc, the growth of dendrites is effectively prevented or delayed. As illustrated by means of the following example, the number of statistical failures of a comparison group of FNC accumulators with the edge treatment of the fiber structure frameworks according to the invention is clearly reduced in contrast to a comparison group of corresponding FNC accumulators without the edge treatment according to the invention. If it is considered that the life of an FNC accumulator statistically can be increased by up to 15% by the application of the invention, the additional costs of the edge treatment are definitely justified.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

Metallized fiber structure framework having treated edge surfaces and faces for use as an electrode or recombination element in accumulators


The process for shaping and slicing primal meat cuts and then packaging the slices to increase the shelf-life thereof includes crust freezing the primal cuts to a depth of approximately 3/8 to 1/2 inch. The crust frozen primal cuts are then tempered for a period of time until the internal temperature reaches approximately 26.degree.-28.degree. F. and the tempered cuts are shaped in a molding press. The shaped primal cuts are then sliced, placed in a tray, and a gas pervious film is applied skin-tight to the slices and the upper surface of the tray. The packages are then frozen before shipment to retain outlets.

In the meat packing industry, various techniques are used in packaging fresh meat products. These fresh meat products may include primal or wholesale cuts and retail cuts. The primals may be vacuum packaged or gas flushed in a barrier bag at the plant level and then sold to the stores. The stores may then further process these primals into various cuts, place these cuts on styrofoam trays which are then overwrapped with a non-barrier film, and merchandise these trays in a refrigerated display case for prospective consumers.
Some of the problems associated with fresh meat products packaged in conventionally overwrapped trays are limited shelf-life, rapid discoloration, excessive purge, and lack of innovative packaging. Depending upon the temperature of the display case, overwrapped tray product can be expected to have a shelf-life of approximately three days. The product is generally considered no longer saleable after three days primarily because of discolorant which is due to rapid oxidation, light catalysis, and bacterial spoilage. In addition, product in overwrapped trays tends to display significant amounts of purge which is generally absorbed by soaker pads; this condition adds to the growth of microorganisms. Further, most conventional overwrapped trays are neither innovative nor especially attractive in appearance.

Process for vacuum packaging fresh meat products


The present invention provides a lubricant for magnetic recording medium which comprises, as an effective component, a phosphazene compound of formula

This application is the National Stage Application of PCT/JP99/02751 filed May 25, 1999.
The present invention relates to a lubricant for magnetic recording medium, such as hard disks of large-capacity recording medium, and metal vapor-deposited tapes for 8 mm video tape recorder or digital video cassette. The present invention is suitable for use as a surface lubricant of a hard magnetic disk serving as a recording medium, in a recording device of contact start stop (CSS) method which establishes a contact between a recording medium and a recording/reproducing element when starting and stopping the device.
Thanks to prevalent internet, intranet, local area network, etc, information can be fetched easily only by gaining access to a network. One of those which support this multimedia era is external recording devices. Of existing large-capacity external recording devices, those of the so-called CSS method are usually employed in which a recording medium layer is provided on a disk substrate having a high strength (hard disk), and the hard disk is rotated at high speed to operate a recording/reproducing element (head). Examples of the hard disk are a stationary magnetic disk, optical disk and optical magnetic disk. Of these, the most prevalent is a device employing the stationary magnetic disk.
In order to increase the capacity of these external recording devices without changing their size, it is necessary to increase the surface recording density of a recording medium layer, for example. This requires that bit size be reduced and the head be brought near the recording medium as much as possible. To reduce a clearance between the head and disk, the unevenness of the disk surface should be minimized. For instance, to obtain a clearance of not more than 100 nm, the unevenness should be not more than 10 nm. However, if the smoothness of the disk surface is increased, the head is liable to be adsorbed onto the disk surface. To obtain high-speed response, it is necessary to increase bit transfer rate and therefore the rotational speed of the disk. For instance, a 3.5-inch hard disk requires a maximum number of revolution of 5400 to 7200 rpm, and the speed of the head as it passes through the periphery of the disk reaches 125 km/hr. Any of the above-mentioned modifications, however, increases considerably the probability of contact between the disk and head, as well as friction therebetween, thus decreasing the reliability.
In view of the foregoing, for protection of the disk surface and head, it is the simplest way to increase the amount of a lubricant applied to the surface of a protective coat for a disk. However, if the amount of a lubricant applied is increased, not only the slide resistance of the. lubricant layer is increased but also the adsorption of the lubricant is enhanced, thereby causing a stop or burning of a spindle motor. For decreasing slide resistance, if a lubricant of low viscosity is used, the lubricant moves and disappears from a protective layer during high-speed rotation of the disk. This causes a contact between the disk and head, and their breakage.
A lubricant, in an extremely simple manner, forms a lubricant film having a uniform thickness of molecules on a protective layer provided on a hard disk such as to reduce friction and wear which may be caused during the rotation of the hard disk and at the start and stop of the device. For protection of the disk and head, there is required a lubricant which has a low slide resistance, large bonding strength to a protective layer, low coefficient of friction, high chemical stability, high thermal stability, high corrosive resistance and lubricity at low temperatures of below xe2x88x9210xc2x0 C., and, which can form ultrathin films at a low vapor pressure. A lubricant for hard disk is required to have no change in coefficient of friction over 20,000 times in CSS durability. That is, the lubricant should be free from abnormalities such as seizing of the head and blemish of the disk, and the variation in coefficient of friction should be no more than 0.3, even over 20,000 times in a CSS repeated test.
From the point of view of chemical stability, strength, ultrathin film formation and smoothness, Diamond Like Carbon (DLC) is used in the surface protective layer of existing hard disks. This protective layer is, as apparent from its structure, mainly composed of carbon, which leads to a low chemical bonding. Its adhesion therefore merely depends upon hydrogen bond with hydrogen atom or nitrogen atom, and interaction such as van der Waals force.
Thus, perfluoroalkyl polyether oligomer (hereinafter referred to as xe2x80x9cPFPExe2x80x9d) is usually employed as a lubricant (Monthly magazine xe2x80x9cTribologyxe2x80x9d, No. 99, November, pp37-38, 1995). PFPE has a low surface energy, chemical inertness, low vapor pressure, and thermal stability, which characteristics are derived from fluorocarbon. Unfortunately, it has a drawback that the bonding strength to the protective layer surface is small because of low surface energy, and the lubricant moves and disappears from the protective layer by centrifugal force during the rotation of a disk. To suppress this, an additive of a secondary component is used (U.S. Pat. No. 4,871,625), however, low compatibility deriving from the fluorocarbon of PFPE causes a phase separation, failing to obtain sufficient effect. In order to afford affinity in PFPE, there has been proposed one method in which a functional group, such as hydroxyl group or acylamide group, is introduced into the terminal or center of the main chain of PFPE (FOMBLIN Z derivative, Ausimont S.p.A). Unfortunately, the functional group having such an active hydrogen might decrease chemical stability due to the friction with the head.
An object of the present invention is to provide a lubricant for hard disk which has excellent CSS durability.
The present invention relates to a lubricant for magnetic recording medium which comprises, as an effective component, a phosphazene compound of formula
[Nxe2x95x90P[O(C6H4)xe2x80x94(A)zxe2x80x94R]a[OCH2xe2x80x94(B)xH]b]yxe2x80x83xe2x80x83(1)
wherein A is xe2x80x94C6H4xe2x80x94 or xe2x80x94OC6H4xe2x80x94, B is fluorine-containing alkylene group, R is hydrogen atom, fluorine atom, C1-4 alkyl, C1-4 alkoxy or C1-4 haloalkyl, a and b are a real number of 0 to 2, satisfying a+b=2, x is 1, 2, 3 or 4, y is 3 or 4, and z is 0 or 1.
Excellent CSS durability of a compound of the invention is based on excellent lubricity, high extreme-pressure performance and excellent adhesion to a DLC protective layer, which characteristics are derived from Compound (1) shown in a number of prior art literatures, e.g., Japanese patent application No. 47680/1982. Here, the excellent adhesion to the DLC protective layer seems to arise from the synergetic effect between the interaction of the terminal hydrogen of fluorocarbon polarized by the adjacent fluorine atom, with hydrogen or nitrogen atom of the DLC protective layer, and the interaction of a phosphazene ring with the DLC protective layer.
In a phosphazene compound of the formula (1) of the invention, a fluorine-containing alkylene group indicated by B is preferably a straight-chain or branched one having 1 to 6 carbon atoms. Such a structure may incorporate an ether linkage. Examples of B are CF2, CF2CF2, CF2CF2O, CF2CF2CF2, CF(CF3)CF2, and CF2CF2OCF2CF2O.
As to R, examples of C1-4 alkyl are methyl, ethyl, propyl and butyl; examples of C1-4 alkoxy are methoxy, ethoxy, propoxy and butoxy; and examples of C1-4 haloalkyl are groups in which the above alkyl group is substituted with fluorine, chlorine or bromine.
In the present invention, the number of R is 1 to 5, preferably 1 to 2. That is, the phenylene group or oxyphenylene group of A can have 1 to 5 of R as a substituent.
These phosphazene compounds are known compounds which are described in, for example, JP-A-164698/1983, JP-A-265394/1987, JP-A-103428/1988, and U.S. Pat. No. 4,613,548, and they can be prepared by, for example, reacting the oligomer of phosphonitrile halide, the alkali metal salt of phenols and alkali metal salt of fluoroalcohols. Examples of the oligomer of phosphonitrile halide are trimer of phosphonitrile chloride, tetramer of phosphonitrile chloride, and a mixture of them. Examples of phenols are phenol, methylphenol, methoxyphenol, trifluoro-methoxyphenol, 3-hydroxybenzotrifluoride, and those which are described in U.S. Pat. No. 4,613,548. Examples of fluoroalcohols are 1,1,xcfx89-trihydroperfluoroalcohols such as 1,1,3-trihydroperfluoropropanol and 1,1,5-trihydroperfluoropentanol, and a mixture of this with 2,2,3,3,3-pentafluoropropanol.
A phosphazene compound of the formula (1) with the desired value of a, b, x, y and z, can be obtained by changing suitably the kind and amount of phenols and fluoroalcohols at the time of preparation.
In the present invention, a phosphazene compound of the formula (1), as it is, can be used as a lubricant. Alternatively, a phosphazene compound of the formula (1) may be dissolved in a suitable organic solvent. Examples of organic solvent are aromatic hydrocarbon such as toluene and xylene, halogenated hydrocarbon such as methylene chloride, chloroform, 1,1,1-trichloroethane, 1,1,2-trichloroethane, trichlorotrifluoroethane (flon 113), ether such as diethyl ether, dimethoxyethane, dioxane and tetrahydrofuran, ester such as ethyl acetate, ethyl butyrate and amyl acetate, alicyclic hydrocarbon such as cyclohexane, cycloheptane and cyclooctane, dimethyl formamide, dimethyl sulfoxide, and a mixed solvent comprising at least two of them.
A phosphazene compound of the formula (1) of the invention can be used together with other lubricant, for example, fluorinated oil such as perfluoropolyether, polyphenyl ether synthetic oil, or other phosphazene compound. Examples of the fluorinated oil are:
HOCH2CF2O(CF2CF2O)r(CF2O)sCF2CH2OH,
wherein
r is 5 to 30, and s is 5 to 30,
piperonyl-OCH2CF2O(CF2CF2O)r(CF2O)sCF2CH2O-piperonyl wherein r is 5 to 30, and s is 5 to 30, and
CF3CF2CF2O(CF2CF2CF2O)tCF2CF3
wherein t is 10 to 30.
Examples of the polyphenyl ether synthetic oil are an isomer mixture of bis(meta-phenoxyphenoxy)benzene, and alkyldiphenyl ether of formula:
wherein R1 and R2 are hydrogen atom or hydrocarbon group having 8 to 24 carbon atoms, u and v are 0 or an integer, and u+v=1 to 4.
Examples of other phosphazene compound are:
[Nxe2x95x90P{OCH2(CF2CF2)pH}2]q
wherein p is 1, 2, 3 or 4, and q is 3 or 4, and
[Nxe2x95x90P(OCH2CF3)(OCH2CF2CF3)]3
A lubricant of the invention is usually employed by forming its coat on a DLC protective layer. The formation of a lubricant layer of the invention is carried out in a known manner, e.g., application. When a lubricant of the invention is applied to a hard disk having a DLC protective layer, spin coating, dip coating or the like is employed. Although its layer thickness is not specifically limited, it may be usually about 10 to 200 xc3x85, preferably about 10 to 50 xc3x85. Adjustment of coat thickness depends upon the vapor pressure of an organic solvent, concentration of a phosphazene compound of the formula (1), drying temperature or the like. It is therefore accomplished by suitably selecting an organic solvent used, or adjusting the concentration or drying temperature.
The present invention will be described in detail with reference to the following Examples and Comparative Examples.


A boom arrangement for moving a work head, which boom arrangement comprises a pillar mounted on a bearing around the vertical axis in a rotating manner, with mounting and rotational members; a lifting boom; a transfer boom; a lifting cylinder arranged between the pillar and the lifting boom; an intermediate lever mounted on the lifting boom; a tow bar, a transfer cylinder arranged between the lifting boom and the tow bar; an intermediate arm; and an arm. The lifting cylinder is mounted by the end on the side of the lifting boom on the intermediate lever, which is mounted on a bearing on the lifting boom in the zone between the end on the side of the lifting boom pillar and the middle of the lifting boom. The tow bar is mounted on one end of the intermediate lever. The arm is mounted on the tow bar by its one end and on the transfer boom by its other end. To achieve a simple and, as regards the operation, safe boom arrangement the lifting cylinder is positioned substantially below the lifting boom as a pushing cylinder, whereby the lifting of the work head is arranged to take place by increasing the length of the lifting cylinder. To achieve optimal courses of movement, the transfer cylinder is mounted on the tow bar in the vicinity of its end facing away from the intermediate lever at the pivot, which is positioned substantially apart from the straight line formed between the pivots of the tow bar ends.

The invention relates to a boom arrangement for moving a multi-function part of a work head, particularly a log loader harvester, which boom arrangement comprises a pillar mounted on a bearing around the vertical axis in a rotating manner, with mounting and rotational members; a lifting boom; a transfer boom; a lifting cylinder arranged between the pillar and the lifting boom; an intermediate lever mounted on the lifting boom; a tow bar, a transfer cylinder arranged between the lifting boom and the tow bar; an intermediate arm; and an arm.
Boom arrangements of the above-mentioned type are nowadays rather known apparatus. Log loaders for log loader harvesters used previously are most frequently what are called parallel loaders, the mechanism of which allows the work head to be moved horizontally by controlling only one actuator. The work head can be for example any wood handling apparatus, such as a cutting head, tree felling head, log collection grapple or some other apparatus.
Examples of the above solutions include the apparatus disclosed in SE patent publication 7411568-4 and Fl patent application 961846.
What the apparatus disclosed in the above publications have in common is that the lifting cylinder is not mounted directly between the pillar and the lifting boom but between the pillar and the lever pivoted in the zone between the root and middle of the lifting boom. The lever then transmits the force of the lifting cylinder further to the boom arrangement. A transfer cylinder is also mounted on said lever, the above-mentioned nearly horizontal parallel movement being achieved by means of this transfer cylinder.
In cranes L 170 V, L 200 V of the Loglift type, the lifting cylinder is positioned above and behind the pillar in an oblique position. The lever is preferably mounted on a bearing at the same pivot as the root of the lifting boom. A weakness of the structure is the relatively great height, which reduces the visual field of the driver. Also, it is difficult to make the lifting cylinder long enough, whereby either the working range of the crane at elevation is limited, or the transportation height of the crane is too great. Further, a weakness of the structural solution is that there is tension load in the lifting cylinder during the operation. The cylinder must therefore be designed in such a way that its volume becomes large and expensive. The oil on the side of the piston rod of the cylinder is continuously under high pressure, and the sealing solutions of both the piston and the piston rod must be of high quality. When the crane is in operation, the oil filling must be controlled all the time on the non-pressure side of the piston. The hydraulics of the structure is not the best possible.
In the crane according to Fl patent application 961846, part of the weaknesses of the above-mentioned solution have been successfully eliminated. Positioning the lifting cylinder upon the lifting boom in a nearly horizontal position reduces the height of the pillar and improves the visual field in the working range. Also, the solution allows the length of the lifting cylinder to be selected great enough as regards the correct working geometry and transportation height. Still, drawbacks of the solution include the tension load of the lifting cylinder and the problem points of the hydraulic system. Further, positioning the lifting cylinder behind the pillar makes it difficult to position the crane sufficiently close to the cabin of the work machine.
The lifting cylinder positioned above the lifting boom can also form a risk factor. The lifting cylinder is subjected to great fatigable tension load during the operation. Thus, some load-bearing structure in the cylinder can fail. Such failure points can include for example the loop of the cylinder liner, the loop of the piston rod and the wire-wraps between the parts. Not only do the work machine and the whole boom arrangement fall to the ground as a result of the fatigue failure, but the lifting cylinder may also move suddenly when it breaks down. If, for example, the loop of the piston rod fails for some reason, the cylinder may bounce backwards and turn, resting on the mounting of its one end, i.e. the end on the side of the pillar. The turning continues backwards until the cylinder hits an obstacle. There is often the cabin of the work machine behind the crane. It is easy to understand that when designed or manufactured defectively, the structure forms a safety risk.
An object of the invention is to provide a boom arrangement by means of which drawbacks of the prior art can be eliminated. This is achieved by means of the boom arrangement according to the invention. The boom arrangement according to the invention is characterized in that the lifting cylinder is positioned substantially below the lifting boom and between the pillar and the intermediate lever as a pushing cylinder, whereby the lifting of the work head is arranged to take place by increasing the length of the lifting cylinder, the tow bar is pivoted at the intermediate lever, at its end facing away from the lifting cylinder, and the transfer cylinder is mounted on the tow bar close to the tow bar end facing away from the intermediate lever, at a pivot positioned substantially apart from the straight line between the pivots a, b of the tow bar ends.
An advantage of the invention is that the boom arrangement can be made small in size and sufficient in length without problems with the transportation height, limited working range or safety. The performance of the hydraulic system is also better than in known solutions, because the volume of the non-pressure oil on the side of the piston rod of the cylinder is small. An advantage of the invention is further that the solution can utilize components of existing cranes manufactured for the loading use of timber. For example, the pillar and the lifting cylinder can be selected directly from a loading crane. This advantage is significant for a machine entrepreneur whose machine selection includes both harvester cranes according to the invention and above-mentioned loading cranes. The lifting cylinder is easy to protect against outside impact by means of a light and preferred structure. Positioning the lifting cylinder on the front side of the boom arrangement allows the crane to be positioned very close to the cabin and rear axle of the work machine, which improves the stability of the work machine. During the operation, the lifting boom must sometimes be lifted in a completely vertical position. In the invention this, too, can take place in a preferred manner. Not only is the stability improved but the rear axle weight and transportation length of the work machine are also reduced compared with the prior art. Hereby, the work machine can move in a more preferred manner than previously both on roads and off-road.