An apparatus and method for removing and recovering up to 98 percent of the residual drilling mud and fluids from drill cuttings for reuse and storing the drill cuttings in a relatively dry state thereby reducing cuttings volume requirements for storage and transport thereby reducing constipation of the drilling process due to disposal congestion. The present invention further provides methods for collecting and transferring drill cuttings in either dry or wet states to various locations on or adjacent the rig for processing, containerization, transport and disposal, thereby reducing handling and contamination thus simplifying recycling while reducing cost.

This is a continuation application of United Kingdom application 9913567.5 filed in the U.K., Jun. 11, 1999, now pending. Priority is claimed to PCT application No. GB 99/04097 filed Dec. 10, 1999.
This invention relates generally to handling of waste materials especially particulate solids. A method of transferring such materials from one location to another, and an apparatus suitable for performing the method, is described hereinafter. The invention finds particular utility in the oil and gas industry for disposal of well or drill cuttings (xe2x80x9chereinafter cuttingsxe2x80x9d) discharged from the solids control system on a well drilling site.
Cuttings are typically pieces of rock, which have been chipped, ground or scraped out of a formation by a drill bit. Various types of drill cutting tools_are in use for this purpose and the invention hereinafter described is not limited to use of any particular type.
The drilling operation is conducted several hundred meters below the operation control point, which means that performance of the drill bit is critical to the operation. The effectiveness of the drill bit during a drilling operation relies upon the continual removal of cuttings; otherwise the drill would rapidly foul up due to accumulation of cuttings. Therefore, the cuttings are normally removed by delivery of a drilling fluid (often referred to as xe2x80x9cdrilling mudxe2x80x9d) down to and around the drill bit in a recirculated manner by use of the drill string and annulus casing well established in the industry.
Accordingly the cuttings are commonly separated from the drilling fluid by devices such as a shale shaker, which captures cuttings and large solids from the drilling fluid during the circulation thereof. Basically, such a device has a sloping, close mesh, screen over which fluid returning from the hole being drilled passes. The screen may be typically of from 200xc3x97200 down to 30xc3x9730 mesh and is vibrated to facilitate separation of the majority of fluids from the solids. The solids captured on the screen travel down the sloping surface to be collected in the shaker ditch or cuttings trough. It is also desirable to recover as much of the expensive drilling fluids as possible. Therefore, other devices, which play a role in the separation of solids from drilling fluids, include cyclone separators, and centrifuges. The cuttings discharged from the shakers, cyclone""s and centrifuges that are collected in the shaker ditch or cuttings trough are still highly contaminated with the drilling fluids and therefore form a slurry or heavy sludge. The slurry or sludge is very difficult to move or otherwise transfer in any conventional manner.
In some cases the cuttings slurry may be discharged directly into a cuttings box where space permits or vacuum collected, which under current practice means that the cuttings are sucked from the cuttings ditch or trough, by an applied vacuum, directly into a cuttings box for transport to an approved disposal site for re-claimation suggested in GB-A-2 286 615. However, in some cases in order to facilitate removal of the cuttings, a collection hopper may be used which allows a particular ground clearance typically of about 4 meters whereby the cuttings are discharged from the hopper by free-fall into open cuttings containers.
It is also proposed there to include another trough for intermediate collection of cuttings. A screw conveyor for lateral displacement of cuttings from beneath the intermediate trough is described. The screw conveyor pushes the cuttings, which fall into it from the trough towards a discharge trap door that opens under the weight of the cuttings to periodically allow the cuttings to fall into the holding tank.
The intermediate trough described remains under the influence of the suction pump to continue delivery of recovered fluid to a recycle system, whilst the screw conveyor below the trough shifts cuttings towards the trap door.
In a more recent operational system a vacuum cuttings hopper is provided including, a helical screw therein on a vertically arranged shaft driven by an overhead motor assists the delivery of the solids to the free-fall outlet for collection below the hopper, The cuttings are further subjected to compression by the helical screw prior to discharge thus extracting and recovering a substantial amount of the remaining fluids in the slurry. The extracted fluid is then withdrawn through a perforated casing around the screw under the action of a pump.
The problems associated with cuttings handling for disposal are familiar to all workers on a drilling installation and include the need for the presence of several storage containers to handle the volumes of cuttings produced and the time demands upon the installation""s crane devoted to the shifting of a filled container to substitute an empty container close to the shaker station. This container xe2x80x9cshuttlingxe2x80x9d routine is not only absorbing useful operational time for the crane but also presents additional physical hazards to workers involved in other tasks in close proximity to the cuttings containers. Furthermore, the cuttings recovery equipment and the containers themselves are usually accessed by workers scaling ladders, or scaffolding or the like staging up to heights often approaching 5 or 6 meters or thereabouts in order to open container lids or service the cuttings handling equipment. Of necessity the containers themselves must be sited close to the cuttings shaker station and be accessible by the crane. These factors have an impact on use of deck space, personnel mobility, and other task completion operations around the deck.
Further the filling and relocation of cuttings containers is dictated by the volume of cuttings being produced by the drilling operation in any given period of time. Therefore, it is essential that the cuttings handling apparatus and its methods of operation be capable of handling the volumes required to maintain production.
An object of the present invention is to provide improvements in cuttings handling for disposal and recovery of reusable drilling fluids and muds from the drill cuttings slurry thereby reducing cost of disposal and recycling. A
object fulfilled by aspects of the invention to be described hereinafter is to provide a drill cuttings recovery system of more compact or efficient design.
A still further object is to provide a more flexible disposal method allowing the operator greater degree of freedom in the options for handling the cuttings prior to disposal.
Generally the invention seeks to provide a system and method for handling of cuttings, which offers an improved alternative to current handling systems.
The invention, according to a first aspect, provides a method for handling cuttings that includes providing a system utilizing a screw pump to remove the cuttings from the cuttings trough and disperse them through a piping system to various disposal points.
The invention according to another aspect, provides a method for handling of cuttings, which method comprises providing a vessel adapted to sustain a reduced internal pressure with respect to external ambient atmospheric pressure, and external pumping means, said vessel and pumping means being operationally connected by means including a conduit, collecting cuttings from a drilling fluid/cuttings separation device in said vessel, removing cuttings from said vessel by means of said pumping means through said conduit whilst maintaining a reduced pressure, and selectively delivering removed cuttings by means of pumping to at least one of a variety of disposal points including a cuttings re-injection apparatus, removable transportable cuttings containers including a barge or the like for shipping to a remote disposal site.
According to another aspect of the invention there is provided an apparatus for handling of cuttings, comprising a vessel adapted to sustain a reduced internal pressure with respect to external ambient atmospheric pressure, and further provide a means for extracting fluids, the apparatus also having operationally connected thereto, external pumping means capable of maintaining the reduced internal pressure and removing the separated fluids while discharging the cuttings to a variety of storage containers or to a cuttings re-injection apparatus.
In accordance with still another aspect of the invention a centrifugal dryer is provided for drying the drill cuttings prior to distribution, by way of a blowers and or vacuum systems, to various holding containers located on or near the rig. This drying process removes the fluids and thereby allows all of the cuttings being produced by the drilling operation to be contained on the rig for longer periods of time prior to removal or re-injection.
Significantly, according to the invention, the proposed use of the pumping means for not only initially collecting the cuttings under vacuum, but also removing cuttings under reduced pressure or xe2x80x9cvacuumxe2x80x9d conditions, and utilizing the pumping means to selectively convey the cuttings onwards via dedicated conduits to a cuttings storage container, or directly into a cuttings re-injection facility, offers several significant advantages.
Firstly, the demands on the crane are reduced because the cuttings containers do not need to be continually cycled around for filling and emptying operations. The containers can be stowed or sited in convenient locations without taking account of the shaker station position other than to ensure that suitable vacuum conduit lines are available or provided to feed the cuttings directly into the containers. The crane then becomes essentially free to fulfill other essential tasks such as handling drill pipe etc. The freedom to locate containers anywhere that a cuttings vacuum transport line can be installed and accessed immediately also provides greater freedom on the deck for operator movement, and greater flexibility in utilization of deck space around the shaker station and elsewhere.
Secondly it offers the possibility of directly off-loading cuttings to a barge or bulk transport ship standing on station close to the drilling facility.
Thirdly, health and safety aspects are enhanced due to reduced contact between workers and the cuttings, who need longer clamber over the cuttings containers to access them thereby reducing contamination hazards and risks of personal injury by falls.
The conduit network may be a fixed installation or arranged so as to permit re-deployment of a selected or each conduit at will. The conduits are designed sufficiently to permit transfer of the particulate solids constituting the cuttings and avoid blockages, and pump overloading but are also sized to avoid loss of vacuum transfer velocity.
It will be understood that the pumping means referred to herein in relation to the various aspects of the invention may consist of one or more pumps having the necessary functions of generating a pressure differential to move cuttings in the desired way and combinations of pumps can be adopted.
Preferably, the pumping means comprises, at least, (i) gas pumping means e.g. a vacuum generating unit capable of creating the desired pressure reduction in the vessel and (ii) a solids displacement means, which may be one of several types suitable to the purpose, including positive displacement pumps, e.g. a piston pump, or paddle devices e.g. using rubber paddles, or a progressive cavity pump capable of continuous displacement of solids, preferably at about 25 tons per hour or more. Advantageously, location of the pumping means external to the vessel is such that solids displacement is so primarily lateral rather than vertical as required for the known solids free-fall under gravity system, which reduces height requirements The vessel can then be installed at ground (deck) level with no height elevation requirements which improves safety for operatives.
In this way equipment provided in accordance with the invention can exhibit a relatively low profile compared with prior art systems and is more easily installed and maintained by operatives with less risk of injury due to falls. Furthermore in contrast with the prior art operational system described above where the vertically arranged helical screw is within the cuttings hopper itself, the pressure vessel arrangement described herein is less complicated in structure and provides for easier care and maintenance operations.
Overall, the system proposed herein results in more efficient use of space in the installation, and reduces hazards associated with earlier systems.
The vessel and pumping means described herein are operationally connected so as to maintain a reduced pressure or vacuum within the system, which may be achievable by fastening arrangements satisfying usual industry pressure vessel standards, including flanged connections and dedicated hard conduits of adequate strength. The reduced pressure can be maintained by a suitable type pump known in the industry or custom built for this system.
It will be understood that primarily the invention addresses solids handling, and the precise nature of the vacuum unit or gas pump is not critical. The arrangement of the invention is such that the pumped cuttings can either be directed from the reduced pressure vessel into appropriate storage facilities such as containers or directly into a cuttings re-injection device enabling the cuttings to be returned to the drilled formation. Furthermore the cuttings can be xe2x80x9cpipedxe2x80x9d off the installation into a barge or similar bulk cargo transporter.
Cuttings re-injection under high pressure back into an earth formation is described in principle in the following U.S. Pat. Nos. 4,942,929, 5,129,409, and 5,109,933, and treatment of drill cuttings is discussed in the following U.S. Pat. Nos. 4,595,422, 5,129,468, 5,361,998 and 5,303,786. However, these early proposals have not been easy to implement in the field for those lacking the appropriate skill and understanding, and this has resulted in cuttings re-injection not gaining wide acceptance amongst operators, especially in offshore drilling installations in the North Sea.
The present invention arises from developments following on from proven re-injection techniques successfully employed by APOLLO Inc. in offshore drilling operations.

Apparatus and method for transferring dry oil and gas well drill cuttings


Automatic dishwashing compositions containing water soluble cationic surfactants are shown to reduce glass dxc3xa9cor fading without composing tea stain removal.

The present disclosure is in the field of machine dishwashing. More specifically, the disclosure relates to automatic dishwashing detergents in granular, liquid, gel, solid and tablet form which contain a cationic, water soluble surfactant for the purpose of reducing the corrosion of decorated glassware.
Machine dishwashing detergents constitute a generally recognized distinct class of detergent compositions. In general, machine dishwashing detergents are mixtures of ingredients whose purpose, in combination, is to breakdown and remove food soils; to inhibit foaming caused by certain food soils; to promote the wetting of wash articles in order to minimize or eliminate visually observable spotting and filming; to remove stains such as might be caused by beverages such as coffee and tea or by vegetable soils such as carotenoid soils; to prevent a buildup of soil films on wash ware surfaces; and to reduce or eliminate tarnishing of flatware. An additional and critical characteristic that the machine dishwashing detergent must possess is the ability to perform all of the above tasks without substantially etching or corroding or otherwise damaging the surface of glasses or dishes. It is particularly critical that the fading and loss of luster from brightly colored decorations on glasses and dishes be prevented.
In conventional institutional and domestic dishwashing formulations, a strongly alkaline solution is produced and is used to wash dishes, glasses, and other cooking and eating utensils. Ordinary tap water can be used in preparing these strongly alkaline cleaning solutions and for rinsing the wash articles subsequent to the cleaning step. However, in European applications, this tap water is often treated (softened) to remove hardness ions such as calcium and magnesium with the result that hard water residues on washware are reduced. Nevertheless, spotting and filming from soil residues and precipitates can remain a problem, especially if the ion exchange unit serving the dishwashing machine is operating inefficiently. This problem can be minimized with a machine dishwashing composition containing a relatively high level of polyphosphate which acts to sequester hardness ions and to aid in soil removal and stabilization. In addition, these detergents usually contain a chlorine bleaching system for stain removal and for an added cleaning boost via oxidation of proteinaceous soils, thus helping to eliminate spotting on glassware.
Although the cleaning performance of these conventional detergent compositions is satisfactory, high phosphate levels, chlorine bleach, and high alkalinity have potential environmental and consumer drawbacks. As a result, an alternative technology was developed to deliver less alkaline products. Similarly, nonphosphated builders are substituted to further improve the environmental profile of the composition. As a consequence of the reduced cleaning efficiency of the modified composition, various detersive enzymes including amylolytic and proteolytic enzymes are included in the detergent composition in order to boost removal of starchy and proteinaceous soils, respectively. Because these enzymes are not compatible with chlorine bleach systems, an oxygen bleaching system can be substituted which can result in a reduction in bleach performance. Often, enzymatic compositions based on oxygen bleaches are formulated with a phosphate builder, in markets where local legislation will allow, to assure good overall performance. An unfortunate weakness in the performance of this alternative technology, both in formulations which are phosphated (i.e., containing inorganic phosphate builder salts) and those which are nonphosphated, is that they are particularly prone to attacking patterned glasses and plates. The striking color of this patterning is often a key reason for the purchase of the article and its rapid fading after a relatively few dishwashing cycles can be particularly noticeable and give rise to an unfavorable rating by the consumer of an otherwise premium performing machine dishwashing product.
It is an object of the present disclosure to provide compositions, suitable for use in machine dishwashing methods, having a reduced tendency to fade or otherwise corrode brightly patterned plates and glasses while at the same time maintaining good cleaning performance towards soiled articles.
UK Patent Application GB 2 295 625 A and WO 96/17051 disclose compositions for use in machine dishwashing comprising a mixture of disilicate and metasilicate in which the weight ratio of disilicate to metasilicate is from 50:1 to 3:2. The minor proportion of metasilicate is described to reduce glass pattern corrosion.
WO 96/20268 describes a copolymer of an organomineral siliconate, obtained by condensation polymerization of an alkali metal disilicate and an alkali metal siliconate, as an additive in a machine dishwashing formulation for the purpose of reducing weight loss and visible corrosion on glass.
WO 96/20129 discloses an alkali metal silicate partially substituted with calcium, magnesium, strontium or cerium as counterion. This modified silicate, when incorporated into a machine dishwashing composition, is described to reduce the weight loss and visible corrosion of washed glassware.
WO 96/12783 describes the inclusion of a crystalline layered silicate of the general formula Na2SixO2+1.yH2O for preserving the color and luster of patterned glassware during machine dishwashing.
The prior art thus describes the use of specific silicates or modified silicates to avoid dishwashing fading or corrosion. This basis restricts the type of formulation to which these solutions are applicable. In particular, corrosion of patterned glassware can be quite severe with formulations of low alkalinity, where silicates are of limited use because of their low stability.
Recently, the use of transition metal salts, particularly of aluminum, has been described for use in mitigating the fading of colors from decorated glassware. The use of aluminum complexes with such as citrate has been described for the same purpose in U.S. Pat. No. 5,624,892. A common problem associated with the use of aluminum ion and polymers for reducing the corrosion of decorated glassware is that good cleaning performance towards soiled articles is often not maintained. It has now been found that the removal of stains caused by beverages such as coffee and tea or by vegetable soils such as carotenoid soils are particularly problematic in this regard and that the removal of tea stain is most seriously hampered.
It has now been discovered that a class of water soluble, cationic surfactants provide an unexpected and superior level of protection to decorated glassware when incorporated into a machine dishwashing detergent. Such protection is illustrated by, but not limited to, the prevention of fading and loss in luster of colored decorations. For a preferred class of water soluble, cationic surfactants, it has surprisingly also been discovered that this protection of decorated articles is not accompanied by any compromise in the cleaning performance towards stains caused by beverages such as coffee and tea.
Preferably, machine dishwashing detergents have
a) an effective amount of a defined cationic, water soluble surfactant; and
b) an effective amount of a builder.
xe2x80x9cWater solublexe2x80x9d surfactants are, unless otherwise noted, herein defined to include solutes which, because of their molecular weight or chemical composition, are soluble to at least the extent of 0.01% by weight in distilled water at 25xc2x0 C. xe2x80x9cCationicxe2x80x9d surfactants herein include solutes in which at least one of the groups making up the chemical structure contains a cationic charge over a portion of the wash pH range of pH 6 to pH 11. Surfactants, as defined in xe2x80x9cPrinciples of Colloid and Surface Chemistryxe2x80x9d, by P. C. Hiemenz and R. Rajagopalan, are a particular class of solutes which show a dramatic effect on the surface tension of the solvent. Water soluble cationic surfactants are thus distinguished from water soluble cationic polymers in that the former are surface active and have a molecular weight which is typically about 1000 or below while the latter have a molecular weight well in excess of 1000 and do not dramatically affect the surface tension of water.
It is expected that the wash pH at which the preferred detergents would be employed would either naturally fall within the pH range 6-11 or, optionally, would be buffered in that range.
The present compositions preferably contain a water soluble, cationic surfactant and a phosphate or nonphosphate builder.
Phosphate Builder
While the compositions utilize a water-soluble phosphate builder, this builder is preferably present at a level of from 1 to 90% by weight, preferably from 10 to 80% by weight, most preferably from 20 to 70% by weight of the composition. Specific examples of water-soluble phosphate builders are the alkali metal, ammonium and alkanol ammonium tripolyphosphates, sodium, potassium and ammonium pyrophosphate, sodium and potassium orthophosphate, sodium polymeta/phosphate in which the degree of polymerization ranges from about 6 to 21, and salts of phytic acid. Sodium or potassium tripolyphosphate is most preferred.
Nonphosphate Builder
When the compositions utilize a water-soluble nonphosphate builder, this builder is preferably present at a level of from 1 to 90% by weight, preferably from 10 to 80% by weight, most preferably from 20 to 70% by weight of the composition. Suitable examples of non-phosphorus-containing inorganic builders include water-soluble alkali metal carbonates, bicarbonates, sesquicarbonates, borates, silicates, metasilicates, and crystalline and amorphous aluminosilicates. Specific examples include sodium carbonate (with or without calcite seeds), potassium carbonate, sodium and potassium bicarbonates, silicates including layered silicates and zeolites. A particularly preferred layered silicate is SKS-6 (available from Hoechst) although others such as SKS-5, SKS-7 and SKS-11 (also available from Hoechst), may also be used. U.S. Pat. No. 4,605,509 provides suitable examples of preferred aluminosilicates. Many useful aluminosilicates are commercially available and these may be crystalline or amorphous in nature. Preferred aluminosilicates include Zeolite A, Zeolite B, Zeolite MAP and Zeolite X. The particle size for these zeolitic materials should be in the preferred range of 0.1-10 microns diameter while individual particles may be even smaller than 0.1 microns so that a large surface area, which promotes exchange kinetics, is exposed. This large surface area also facilitates the role of zeolites in their role as surfactant carriers. This advantage of modifying zeolite and other builder morphology to most efficiently also serve as surfactant carriers can always be suitably exploited by those skilled in the art.
Organic detergent builders can also be used. These are typically, but are not restricted to, polycarboxylate materials. Polycarboxylate builders are those which have at least two carboxylate groups present in the compound and may be used either in the acidic form or as the neutralized soluble salt form. The alkali metal salts, such as lithium, sodium, and potassium or the ammonium or alkanol ammonium salts are the preferred forms. Within the class of polycarboxylate builders are various sub-classes of materials.
Citrate derived builders, preferably their soluble alkali metal salts, most preferably the sodium salt, are especially important with respect to machine dishwashing formulations. This importance is derived from their biodegradability and from their agricultural based availability. Malonates and dipicolinates are another subclass of builder materials.
Ether polycarboxylates are another important example of polycarboxylate builders. This class can be exemplified by the particularly preferred oxydisuccinate which has been revealed by Lamberti et. al. in U.S. Pat. No. 3,635,830 and by Berg et. al. in U.S. Pat. No. 3,128,287. Other examples of ether polycarboxylates include the xe2x80x9cTMS/TDSxe2x80x9d builders disclosed in U.S. Pat. No. 4,663,071. Cyclic ether polycarboxylates as disclosed in U.S. Pat. Nos 4,158,635; 4,120,874; 4,102,903; 3,923,679; and 3,835,163 are also builders which can be employed. Other classes of materials that fall into the category of ether polycarboxylates builders are the tartrate monoacetates, tartrate diacetates, oxydiacetates, tartrate monosuccinates, tartrate disuccinates and carboxymethyloxy succinates. 3,3-Dicarboxy-4-oxa-1,6-hexanedionates and the related compounds which are revealed in U.S. Pat. No. 4,566,984, mellitic acid and 3,5-dicarboxybenzoic acid are also suitable builders.
Another sub class of polycarboxylates are those derived by substitution onto an ammonia core or the aminopolycarboxylates. Examples within this class, but not restricted to, are ethylenediamine tetraacetates, methyl glycinediacetates and the particularly preferred nitrilotriacetates.
Builders derived from succinic acid are also useful in machine dishwashing formulations. Examples of these include the C5-C20 alkyl and alkenyl succinates. Particularly preferred examples of these are lauryl succinates (disclosed in European Patent Application 86200690) and 2-dodecenylsuccinate. Other non-limiting examples include myristyl-succinate, palmitylsuccinate and 2-pentadecenylsuccinate.
Polymeric polycarboxylates also serve as valuable building materials in machine dishwashing formulations. These include polycarboxylates such as polyacrylates, polymaleates, polyacetates, polyhydroxyacrylates, polyacrylate/polymaleate and polyacrylate/polymethacrylate copolymers, acrylate/maleate/vinyl alcohol terpolymers, and polyacetal carboxylates, and polyaspartates and mixtures thereof. Such carboxylates are described in U.S. Pat. Nos. 4,144,226, 4,146,495 and 4,686,062. Other examples of polymeric builders include oxidized starches and oxidized heteropolymeric polysaccharides. The acrylate/maleate copolymers and acrylate/maleate/vinyl alcohol terpolymers are especially preferred.
Simple fatty acid monocarboxylates, either in acid or salt form of the C12-C20 fatty acids, may be used either in conjunction with the other mentioned builders, esp. the succinates or tartarates, or alone to provide more building capacity. While such builders can act as antifoaming/defoaming systems, which is a desirable attribute in machine dishwashing formulations, they tend, under hard water conditions, to deposit residues on surfaces and hence are not preferred.
Organic builders that do not rely on the carboxylate functionality also exist and examples of these include the fatty acid sulfonates, phytates, phosphonates (see for e.g. U.S. Pat. Nos. 3,159,581; 3,213,030; 3,422,021, 3,400,148 and 3,422,137), alkanehydroxyphosphonates (e.g. Ethane-1-hydroxy-1,1-diphosphonate) and polyhydroxysulfonates (e.g. 3,5-dihydroxy-2,4,6-trisulfonic acid phenol),
Alkali metal citrates, nitrilotriacetates, oxydisuccinates, polyphosphonates organic builders. The citrates and oxydisuccinates can also be used in combinations with BRITESIL and/or layered silicates.
The foregoing detergent builders are meant to illustrate but not limit the types of builders that can be employed.
Water Soluble Cationic Surfactant
xe2x80x9cWater solublexe2x80x9d surfactants are, unless otherwise noted, herein defined to include solutes which, because of their molecular weight or chemical composition, are soluble to at least the extent of 0.01% by weight in distilled water at 25xc2x0 C. xe2x80x9cCationicxe2x80x9d surfactants herein comprise solutes in which at least one of the groups making up the chemical structure contains a cationic charge over a portion of the wash pH range of pH 6 to pH 11. xe2x80x9cSurfactantsxe2x80x9d, as defined in xe2x80x9cPrinciples of Colloid and Surface Chemistryxe2x80x9d, by P. C. Hiemenz and R. Rajagopalan, are a particular class of solutes which show a dramatic effect on the surface tension of the solvent. Water soluble cationic surfactants are thus distinguished from water soluble cationic polymers in that the former are surface active and have a molecular weight which is typically about 1000 or below while the latter have a molecular weight well in excess of 1000 and do not dramatically affect the surface tension of water.
It is expected that the wash pH at which the preferred detergents would be employed would either naturally fall within the pH range 6-11 or, optionally, would be buffered in that range.
Specifically, surfactants useful in this invention may be represented structurally as organic quaternary ammonium compounds as in formula I,
wherein R1 can generally be a straight, branched, or cyclic; saturated or unsaturated; substituted or unsubstituted group containing from about 6 to about 20 carbon atoms. R2, R3, and R4 can generally each independently be a straight, branched, or cyclic; saturated or unsaturated; substituted or unsubstituted group containing from about 1 to about 10 carbon atoms or a poly oxyalkene condensate of about 1 to about 25 oxyalkene units. It is understood that two of R2, R3, and R4 may be taken together with the nitrogen group to which they are attached to form an aliphatic or aromatic heterocycle as in derivatives of pyrrole, pyrrolidone, or piperidine. Similarly, it is understood that R2, R3, and R4 may be taken together with the nitrogen group to which they are attached to form an aromatic heterocylce as in derivatives of pyridine. X is an anion chosen from chloride, iodide, bromide, methyl sulfate, ethyl sulfate, sulfate and the like.
In a preferred embodiment of the present invention, R1 is a linear, saturated group containing from about 6 to about 20 carbon atoms, R2 is a linear, saturated group containing from about 1 to about 2 carbon atoms, R3 is a linear, saturated group containing from about 1 to about 2 carbon atoms or is a poly oxyethene condensate given by the general formula
xe2x80x94(CH2CH2O)mHxe2x80x83xe2x80x83(II)
and R4 is a linear, saturated group containing from about 1 to about 2 carbon atoms or is a poly oxyethene condensate given by the general formula
xe2x80x94(CH2CH2O)nHxe2x80x83xe2x80x83(III)
with the understanding that the integers m and n are such that their sum is from about 2 to about 40 and with the stipulation that one of R3 or R4 must be a poly oxyethene condensate. X is an anion chosen from chloride, iodide, bromide, methyl sulfate, ethyl sulfate, sulfate and the like.
Examples of preferred cationic surfactants include, but are not limited to, methyl bis-(polyethoxy ethanol) coco ammonium chloride, ethyl bis-(polyethoxy ethanol) tallow ammonium chloride, and methyl bis-(2-hydroxyethyl) coco ammonium chloride. These materials are provided by the Witco Corporation under the trade names Variquat K-1215, Adogen 66, and Variquat 638, respectively.
In a particularly preferred embodiment, R1 is a linear, predominately saturated group containing primarily from about 8 to about 18 carbon atoms, as would be found in derivatives from tallow or coconut oil, R2 is a methyl or an ethyl radical, R3 is a methyl or an ethyl radical or is a poly oxyethene condensate given by the general formula
xe2x80x94(CH2CH2O)mHxe2x80x83xe2x80x83(II)
and R4 is a methyl or an ethyl radical or is a poly oxyethene condensate given by the general formula
xe2x80x94(CH2CH2O)nHxe2x80x83xe2x80x83(III)
with the understanding that the integers m and n are such that their sum is from about 3 to about 14 and with the stipulation that one of R3 or R4 must be a poly oxyethene condensate. It has been fond that if the sum of m and n are less than about 3 or greater than about 14, the benefits of the cationic surfactant decrease (increased fading below 3 and decreased stain removal about 14). X is an anion chosen from chloride, iodide, bromide, methyl sulfate, ethyl sulfate, sulfate and the like.
Examples of cationic surfactants comprising the particularly preferred embodiment of the present invention include, but are not limited to, methyl bis-(polyethoxy ethanol) coco ammonium chloride, and methyl bis-(polyethoxy ethanol) tallow ammonium chloride. These materials are provided by the Witco Corporation under the trade names Rewoquat CPEM, and as the experimental compound DPSC 287-21, respectively.
An effective amount of said cationic surfactant is 0.1 to 20%, preferably 0.5 to 10%, most preferably 1 to 5%, all by weight, of the total detergent formulation.
Optional Ingredients
In addition to the essential ingredients described herein above, the presently disclosed compositions may be formulated as detergent compositions having conventional ingredients, preferably selected from enzymes, buffering systems, oxygen bleaching systems, surfactants, heavy metal ion sequestrants, antiscalants, corrosion inhibitors, and antifoams.
Enzymes
Enzymes capable of facilitating the removal of soils from a substratexe2x80x94detersive enzymesxe2x80x94may also be present in a combined amount of up to about 10% by weight of active enzyme. Such enzymes include proteases, amylases, lipases, esterases, cellulases, pectinases, lactases and peroxidases as conventionally incorporated into detergent compositions. While compositions with single enzymes may be used it is highly preferred for machine dishwashing formulations to use combinations of two or more enzymes. Furthermore, since most formulations contain oxidative bleaches, enzymes, especially amylases and proteases, which have been engineered to have improved bleach stability are highly preferred. Such engineering of enzymes is known (see for e.g. J. Biol. Chem. 260, 11, 1985, 6518-6521).
While enzymes may be derived from yeast, fungal, bacterial, animal or vegetable origin, the choice of which one to use is really determined by finding the most suitable intersection of the optima with respect to activity v/s pH, and stability to heat, bleach and other functional ingredients (e.g. surfactants, builders etc.) present in the formulation. It is known that with respect to such selection criteria bacterial proteases and amylases and fungal cellulases are preferred.
Examples of proteases include Alcalase(copyright), Savinase(copyright) and Esperase(copyright) from Novo Industries A/S; Purafect OxP(copyright), ex. Genencor; and Maxatase(copyright) from International BioSynthetics Inc. Other examples of proteases include Protease A and Protease B as disclosed in European Patent Application 130,756 published Jan. 9, 1985 and the proteases disclosed in U.S. Pat. Nos. 5,677,272 and 5,679,630. The proteases Alcalase and Savinase are preferred enzymes.
Examples of amylases include Termamyl(copyright) and Duramyl(copyright) from Novo Industries A/S; Purafect OxAm(copyright), from Genencor Int. and Rapidase(copyright) from International BioSynthetics Inc and amylases such as those described in British Patent Specification No. 1,296,839. The amylases Termamyl and Duramyl are preferred. Amylase variants produced by site directed mutagenesis of precursor amylases which are currently available and which have increased stability, relative to current references such as Termamyl in one or more properties such as temperature stability, especially at wash temperatures of 45-75xc2x0 C.; alkaline stability, especially at wash pH values of 8.5-11 and oxidative stability, especially in the presence of environments containing peracids are especially preferred. Examples of such stability enhanced amylases are disclosed in WO/94/02597 wherein variants of precursor enzymes such as Termamyl(copyright) have been disclosed.
The use of lipase enzymes in ADD formulations is known in the art as disclosed in U.S. Pat. No. 5,719,112. Commercial examples of lipases include Lipolase(copyright)xe2x80x94derived from Humicola lanuginosaxe2x80x94from Novo Industries A/S, Amano-CES from Toyo Jozo Co., Tagata, Japan, and lipases derived from Chromobacter viscosum available from U.S. Biochemical Corp., U.S.A and Diosynth Co., The Netherlands. Lipolase(copyright) and variants of lipases from Humicola lanuginosa as disclosed in WO92/05249 are preferred.
Cellulases such as those disclosed in U.S. Pat. No. 4,435,307, GB-A-2,075,028 and GB-A-2,095,275 may also be included in the instant invention. The commercially available Carezyme(copyright) from Novo Industries A/S is especially preferred.
The relatively fragile nature of enzymes necessitates the use of techniques to stabilize them from other reactive species present in the composition or under in-use conditions. Such techniques have been revealed in U.S. Pat. Nos. 3,600,319; 3,519,570 and in Eur. Pat. Application No. 0 199 405. Means for incorporating enzymic materials into detergent compositions are disclosed in U.S. Pat. No. 3,553,139.
Buffering System
The buffering system may be present in order to deliver a pH of about 6 to about 11 in the wash water. A controlled pH profile during the entire wash cycle allows for maximum efficiency to be obtained from the various cleaning agents such as enzymes, bleaches and surfactants. Soils are naturally acidic and their presence will tend to lower the intrinsic pH of the wash solution. Resistance to such undesirable pH fluctuations are achieved by the use of buffering agents. The preferred pH range of aqueous solutions of machine dishwashing formulations is 6.5-11 with the particularly preferred range being from 7.0-10.5. The pH delivery and buffering in the system can be provided by various ingredients which can be selected from water-soluble alkali metal (a) carbonates, bicarbonates and/or sesquicarbonates-(b) citrates (c) hydroxides (d) borates (esp. borax) (e) silicates (f) crystalline and amorphous aluminosilicates (g) phytic acid and mixtures or combinations of (a)-(g).
Nonlimiting examples within the class of materials designated silicates include sodium silicate, sodium metasilicate and layered silicates such as those described in U.S. Pat. No. 4,664,839 which are comprised of SiO2:Na2O ratios in the range of 1.6:1 to 3.2:1. Commercially available layered silicates include NaSKS-5(copyright), NaSKS-6(copyright), NaSKS-7(copyright), and NaSKS-11(copyright), all from Hoechst. Other silicates commerically available include the BRITESIL(copyright) H20 AND BRITESIL(copyright) H24 from PQ Corp. Silicates are normally incorporated in at levels where they do not negatively impact the spotting and filming performance of the machine dishwashing formulation.
Particularly preferred options are sodium and potassium carbonate, sodium and potassium bicarbonates, sodium citrate, borax, sodium metasilicate and the silicates BRITESIL(copyright) H20 and NaSKS-6(copyright) as well as binary combinations of sodium citrate and sodium carbonate.
Other ingredients added into the formulation for improved building and sequestration can also serve the role of a primary and/or supplementary buffering agent. These include, in a non limiting list of examples, ethylenediamine tetraacetates, nitrilotriacetates, tartarate monosuccinates, tartarate disuccinates, oxydisuccinates, carboxymethoxysuccinates and sodium benzene polycarboxylate salts.
Other techniques for controlling pH such as pH jump systems, and the use of dual compartments have been previously disclosed and are well known in the art.
In certain cases it may be advantageous to have a controlled change of the pH during the wash cycle and techniques such as the delayed release of acidity as disclosed in U.S. Pat. No. 5,747,438 or the use of enzymatic systems to provide delayed release of alkalinity such as those disclosed in WO 9736984 are known to those skilled in the art. Such practices are not excluded from the present disclosure.
Oxygen Bleaching Systems
The following are preferred oxygen bleach sources:
Peroxy Bleaching Agentsxe2x80x94The oxygen bleaching agents of the compositions include organic peroxy acids and diacylperoxides. Typical monoperoxy acids useful herein include alkyl peroxy acids and aryl peroxy acids such as:
i) peroxybenzoic acid and ring-substituted peroxybenzoic acids, e.g., peroxy-alpha-naphthoic acid, and magnesium monoperoxyphthalate;
ii) aliphatic and substituted aliphatic monoperoxy acids, e.g., peroxylauric acid, peroxystearic acid, epsilon-phthalimido-peroxyhexanoic acid and o-carboxybenzamido peroxyhexanoic acid, N-nonylamidoperadipic acid and N-nonylamidopersuccinic acid;
iii) Cationic peroxyacids such as those described in U.S. Pat. Nos. 5,422,028, 5,294,362; and 5,292,447 are herein incorporated by reference; and
iv) Sulfonyl peroxyacids such as compounds described in U.S. Pat. No. 5,039,447 (Monsanto Co.), herein incorporated by reference.
Typical diperoxy acids useful herein include alkyl diperoxy acids and aryl diperoxy acids, such as:
v) 1,12-diperoxydodecanedioic acid;
vi) 1,9-diperoxyazelaic acid;
vii) diperoxybrassylic acid; diperoxysecacic acid and diperoxy-isophthalic acid;
viii) 2-decyldiperoxybutan-1,4-dioic acid; and
ix) N,N1-terephthaloyl-di(6-aminopercaproic acid).
A typical diacylperoxide useful herein includes dibenzoylperoxide.
Inorganic peroxygen compounds are also suitable. Examples of these materials are salts of monopersulfate (available commercially as the trisalt Oxone(copyright) from Dupont Chem. Co.), perborate monohydrate, perborate tetrahydrate, percarbonate, pyrophosphate peroxyhydrate, urea peroxyhydrate, and sodium peroxide and mixtures thereof. Sodium perborate monohydrate and sodium percarbonate are particularly preferred.
Preferred peroxy bleaching agents include epsilon-phthalimido-peroxyhexanoic acid, o-carboxybenzamidoperoxyhexanoic acid, and mixtures thereof.
The organic peroxy acid is present in the composition in an amount such that the level of organic peroxy acid in the wash solution is about 1 ppm to about 300 ppm AvOx, preferably about 2 ppm to about 200 ppm AvOx.
The oxygen bleaching agent may be incorporated directly into the formulation or may be encapsulated by any number of encapsulation techniques.
A preferred encapsulation method is described in U.S. Pat. No. 5,200,236 issued to Lang et al., herein incorporated by reference. In the patented method, the bleaching agent is encapsulated as a core in a paraffin wax material having a melting point from about 40xc2x0 C. to 50xc2x0 C. The wax coating has a thickness of from 100 to 1500 microns.
Bleach Precursorsxe2x80x94Suitable peracid precursors for peroxy bleach compounds have been amply described in the literature, These include, but are not limited to, those referenced in GB Nos. 836,988; 855,735; 907,356; 907,358; 907,950; 1,003,310 and 1,246,339; U.S. Pat. Nos. 3,332,882; 4,128,494; 4,412,934; 4,634,551 and 4,915,854 and WO 96/16155.
Typical examples of precursors are polyacylated alkylene diamines, such as N,N,Nxe2x80x2,Nxe2x80x2-tetraacetylethylene diamine (TAED) and N,N,Nxe2x80x2,Nxe2x80x2-tetraacetylmethylene diamine (TAMD); acylated glycolurils, such as tetraacetylglycoluril (TAGU); xylose tetraacetate, glucose pentaacetate, triacetylcyanurate, sodium sulfophenyl ethyl carbonic acid ester, sodium acetyloxybenene sulfonate (SABS), sodium nonanoyloxy benzene sulfonate (SNOBS) and choline sulfophenyl carbonate. Peroxybenzoic acid precursors are known in the art, e.g., as described in GB-A-836,988. Examples of suitable precursors are phenylbenzoate; phenyl p-nitrobenzoate; o-nitrophenyl benzoate; o-carboxyphenyl benzoate; p-bromophenylbenzoate; sodium or potassium benzoyloxy benzene-sulfonate; and benzoic anhydride.
Another class of bleach activators are the benzoxazin derivatives as have been disclosed in U.S. Pat. No. 4,966,723.
U.S. Pat. No. 4,634,551 discloses a class of precursor compounds which upon perhydrolysis lead to the formation of peracids containing amide groups within their strucutre. Examples of such precursors include, in a non limiting sense, (6-octanamido-caproyl)oxybenzenesulfonate, (6-nonanamido-caproyl)oxybenzenesulfonate and (6-decanamido-caproyl)oxybenzenesulfonate. Mixtures of such compounds also constitute suitable bleach precusors. Another class of precursor molecules are the acyl lactams such as the acyl valerolactams and the acyl caprolactams. The acyl substituent on these lactam derivatives can be an alkyl, aryl, alkaryl, or alkoxyaryl, containing from about 1 to 12 carbon atoms or substituted phenyl groups containing 6 to 18 carbon atoms. Examples of such acyl groups non limitingly include benzoyl, octanoyl, nonanoyl, decanoyl, undecenoyl, and 3,5,5-trimethylhexanoyl. U.S. Pat. No. 4,545,784 reveals acylcaprolactams adsorbed onto sodium perborate.
Quaternary substituted bleach precursors are also well known in the art. Examples of such compounds have been disclosed in U.S. Pat. Nos. 5,686,015; 5,269,962; 5,106,528; 5,093,022; 4,988,451; 4,904,406; 4,818,426; 4,397,757; 4,283,301 as well as in British Pat. 1,382,594 and in EP 552,812 A1; EP 475,512; EP 458,396 and EP 284,292.
Other types of bleach precursors, some multiply substituted and others with cationic groups have been revealed in U.S. Pat. Nos. 5,560,862; 5,584,888 and 5,460,747.
U.S. Pat. No. 5,753,138 teaches on the use of bleach precursors which are effective at low concentrations of perhydroxide while U.S. Pat. No. 5,739,096 teaches about the use of cyanopyridine N-oxides as bleach activators.
Preferred peroxygen bleach precursors are sodium p-benzoyloxybenzene sulfonate, N,N,Nxe2x80x2,Nxe2x80x2-tetraacetylethylene diamine, sodium nonanoyloxybenzene sulfonate and choline sulfophenyl carbonate.
The peroxygen bleach precursors are preferably present in the composition in an amount from about 1 to about 20 weight percent, preferably from about 1 to about 15 wt. %, most preferably from about 2 to about 15 wt. %. To deliver a functional peroxygen bleach from a precursor, a source of hydrogen peroxide is required. The hydrogen peroxide source is preferably a compound that delivers hydrogen peroxide on dissolution. Preferred sources of hydrogen peroxide are sodium perborate, either as the mono- or tetrahydrate and sodium percarbonate. The source of hydrogen peroxide, when included in these compositions is present at a level of about 1% to about 40% by weight, preferably from about 2% to about 30% by weight, most preferably from about 4% to about 25% by weight.
Bleach Catalystxe2x80x94An effective amount of a bleach catalyst can also be present in the invention. A number of organic catalysts are available such as the activated imines as described in U.S. Pat. Nos. 5,753,599; 5,693,603; 5,041,232; 5,047,163 and 5,463,115 and those containing quaternary imine salts as described in U.S. Pat. Nos. 5,550,256 and 5,482,515. Another class of organic bleach catalysts are the dioxiranes as have been disclosed in U.S. Pat. Nos. 5,755,993; 5,525,121 and 3,822,114.
Transition metal bleach catalysts are also useful, especially those based on manganese, iron, cobalt, titanium, molybdenum, nickel, chromium, copper, ruthenium, tungsten and mixtures thereof. These include simple water-soluble salts such as those of iron, manganese and cobalt as well as catalysts containing complex ligands.
The German patent DE1,529,905 teaches on the use of diimine complexes of manganese, iron, cobalt, ruthenium or molybdenum as bleach catalysts.
Suitable examples of manganese catalysts containing organic ligands are described in U.S. Pat. Nos. 4,728,455, 5,114,606, 5,153,161, 5,194,416, 5,227,084, 5,244,594, 5,246,612, 5,246,621, 5,256,779, 5,274,147, 5,280,117 and European Pat. App. Pub. Nos. 544,440, 544,490, 549,271 and 549,272. Preferred examples of these catalysts include MnIV2(u-O)2(1,4,7-trimethyl-1,4,7-triazacyclononane)2(PF6)2, MnIII2(u-O)1(u-OAc)2(1,4,7-trimethyl-1,4,7-triazacyclononane)2(ClO4)2, MnIV4(u-O)6(1,4,7-triazacyclononane)4(ClO4)4, MnIIIMnIV4(u-O)1(u-OAc)2(1,4,7-trimethyl-1,4,7-triazacyclononane)2(ClO4)3, MnIV(1,4,7-trimethyl-1,4,7-triazacyclononane)-(OCH3)3(PF6), and mixtures thereof. Other metal-based bleach catalysts include those disclosed in U.S. Pat. Nos. 4,430,243 and 5,114,611.
Iron and manganese salts of aminocarboxylic acids in general are useful herein including iron and manganese aminocarboxylate salts disclosed for bleaching in the photographic color processing arts. A particularly useful transition metal salt is derived from ethylenediaminedisuccinate and any complex of this ligand with iron or manganese.
Another type of bleach catalyst, as disclosed in U.S. Pat. No. 5,114,606, is a water soluble complex of manganese (II), (III), and/or (IV) with a ligand which is a non-carboxylate polyhydroxy compound having at least three consecutive Cxe2x80x94OH groups. Preferred ligands include sorbitol, iditol, dulsitol, mannitol, xylithol, arabitol, adonitol, meso-erythritol, meso-inositol, lactose and mixtures thereof. Especially preferred is sorbitol.
U.S. Pat. No. 5,114,611 teaches a bleach catalyst comprising a complex of transition metals, including manganese, cobalt, iron or copper with a non-(macro)-cyclic ligand. Other examples include Mn gluconate, Mn(CF3SO3)2, and binuclear Mn complexed with tetra-N-dentate and bi-N-dentate ligands, including [bipy2MnIII(u-O)2MnIVbipy2]xe2x80x94(ClO4)3.
Other bleach catalysts are described, for example, in European Pat. App. Pub. Nos. 408,131 (cobalt complexes), 384,503 and 306,089 (metallo-porphyrins), U.S. Pat. No. 4,728,455 (manganese/multidenate ligand), U.S. Pat. No. 4,711,748 (absorbed manganese on aluminosilicate), U.S. Pat. No. 4,601,845 (aluminosilicate support with manganese, zinc or magnesium salt), U.S. Pat. No. 4,626,373 (manganese/ligand), U.S. Pat. No. 4,119,557 (ferric complex), U.S. Pat. No. 4,430,243 (chelants with manganese cations and non-catalytic metal cations), and U.S. Pat. No. 4,728,455 (manganese gluconates).
Useful catalysts based on cobalt are described in Pat. App. Pub. Nos. WO 96/23859, WO 96/23860 and WO 96/23861 and U.S. Pat. Nos. 5,559,261 and 5,703,030. WO 96/23860 describes cobalt catalysts of the type [ConLmXp]zYz, where L is an organic ligand molecule containing more than one heteroatom selected from N, P, O and S; X is a co-ordinating species; n is preferably 1 or 2; m is preferably 1 to 5; p is preferably 0 to 4 and Y is a counterion. One example of such a catalyst is N,Nxe2x80x2-Bis(salicylidene)ethylenediaminecobalt (II). Other cobalt catalysts described in these applications are based on Co(III) complexes with ammonia and mon-, bi-, tri- and tetradentate ligands such as [Co(NH3)5OAc]2+ with Clxe2x88x92, OAcxe2x88x92, PF6xe2x88x92, SO4=, and BF4xe2x88x92 anions.
Certain transition-metal containing bleach catalysts can be prepared in situ by the reaction of a transition-metal salt with a suitable chelating agent, for example, a mixture of manganese sulfate and ethylenediaminedisuccinate. Highly colored transition metal-containing bleach catalysts may be co-processed with zeolites to reduce the color impact.
When present, the bleach catalyst is typically incorporated at a level of about 0.0001 to about 10% by wt., preferably about 0.001 to about 5% by weight.
Surfactants
Optionally, a surfactant selected from the list including anionic, nonionic, cationic, amphoteric, and zwitteronic surfactants and mixtures of these surface active agents may be included in the machine dishwashing formulation. Such surfactants are well known in the detergent arts and are described at length in xe2x80x9cSurface Active Agents and Detergentsxe2x80x9d, Vol. 2 by Schwartz, Perry and Birch, Interscience Publishers, Inc., 1959, herein incorporated by reference.
Preferred surfactants are one or a mixture of:
Anionic surfactantsxe2x80x94Anionic synthetic detergents can be broadly described as surface active compounds with one or more negatively charged functional groups. An important class of anionic compounds are the water-soluble salts, particularly the alkali metal salts, of organic sulfur reaction products having in their molecular structure an alkyl radical containing from about 6 to 24 carbon atoms and a radical selected from the group consisting of sulfonic and sulfuric acid ester radicals.
Primary Alkyl Sulfates
R7OSO3M
where R7 is a primary alkyl group of 8 to 18 carbon atoms and M is a solubilizing cation. The alkyl group R7 may have a mixture of chain lengths. It is preferred that at least two-thirds of the R7 alkyl groups have a chain length of 8 to 14 carbon atoms. This will be the case if R7 is coconut alkyl, for example. The solubilizing cation may be a range of cations which are in general monovalent and confer water solubility. An alkali metal, notably sodium, is especially envisaged. Other possibilities are ammonium and substituted ammonium ions, such as trialkanolammonium or trialkylammonium.
Alkyl Ether Sulfates
R7O(CH2CH2O)nSO3M
where R7 is a primary alkyl group of 8 to 18 carbon atoms, n has an average value in the range from 1 to 6 and M is a solubilizing cation. The alkyl group R7 may have a mixture of chain lengths. It is preferred that at least two-thirds of the R7 alkyl groups have a chain length of 8 to 14 carbon atoms. This will be the case if R7 is coconut alkyl, for example. Preferably n has an average value of 2 to 5.
Fatty Acid Ester Sulfonates
R8CH(SO3M)CO2R9
where R8 is an alkyl group of 6 to 16 atoms, R9 is an alkyl group of 1 to 4 carbon atoms and M is a solubilizing cation. The group R8 may have a mixture of chain lengths. Preferably at least two-thirds of these groups have 6 to 12 carbon atoms. This will be the case when the moiety R8CH(xe2x80x94)CO2(xe2x80x94) is derived from a coconut source, for instance. It is preferred that R9 is a straight chain alkyl, notably methyl or ethyl.
Alkyl Benzene Sulfonates
R10ArSO3M
where R10 is an alkyl group of 8 to 18 carbon atoms, Ar is a benzene ring (C6H4) and M is a solubilizing cation. The group R10 may be a mixture of chain lengths. Straight chains of 11 to 14 carbon atoms are preferred.
Paraffin sulfonates having 8 to 22 carbon atoms, preferably 12 to 16 carbon atoms, in the alkyl moiety. These surfactants are commercially available as Hostapur SAS from Hoechst Celanese.
Olefin sulfonates having 8 to 22 carbon atoms, preferably 12 to 16 carbon atoms. U.S. Pat. No. 3,332,880 contains a description of suitable olefin sulfonates.
Organic phosphate based anionic surfactants include organic phosphate esters such as complex mono- or diester phosphates of hydroxyl-terminated alkoxide condensates, or salts thereof. Included in the organic phosphate esters are phosphate ester derivatives of polyoxyalkylated alkylaryl phosphate esters, of ethoxylated linear alcohols and ethoxylates of phenol. Also included are nonionic alkoxylates having a sodium alkylenecarboxylate moiety linked to a terminal hydroxyl group of the nonionic through an ether bond. Counterions to the salts of all the foregoing may be those of alkali metal, alkaline earth metal, ammonium, alkanolammonium and alkylammonium types.
Particularly preferred anionic surfactants are the fatty acid ester sulfonates with formula:
R8CH(SO3M)CO2R9
where the moiety R8CH(xe2x80x94)CO2(xe2x80x94) is derived from a coconut source and R9 is either methyl or ethyl; primary alkyl sulfates with the formula:
R7OSO3M
wherein R7 is a primary alkyl group of 10 to 18 carbon atoms and M is a sodium cation; and paraffin sulfonates, preferably with 12 to 16 carbon atoms to the alkyl moiety.
Nonionic surfactantsxe2x80x94Nonionic surfactants can be broadly defined as surface active compounds with one or more uncharged hydrophilic substituents. A major class of nonionic surfactants are those compounds produced by the condensation of alkylene oxide groups with an organic hydrophobic material which may be aliphatic or alkyl aromatic in nature. The length of the hydrophilic or polyoxyalkylene radical which is condensed with any particular hydrophobic group can be readily adjusted to yield a water-soluble compound having the desired degree of balance between hydrophilic and hydrophobic elements. Illustrative, but not limiting examples, of various suitable nonionic surfactant types are:
polyoxyalkene condensates of aliphatic carboxylic acids, whether linear- or branched-chain and unsaturated or saturated, especially ethoxylated and/or propoxylated aliphatic acids containing from about 8 to about 18 carbon atoms in the aliphatic chain and incorporating from about 2 to about 50 ethylene oxide and/or propylene oxide units. Suitable carboxylic acids include xe2x80x9ccoconutxe2x80x9d fatty acids (derived from coconut oil) which contain an average of about 12 carbon atoms, xe2x80x9ctallowxe2x80x9d fatty acids (derived from tallow-class fats) which contain an average of about 18 carbon atoms, palmitic acid, myristic acid, stearic acid and lauric acid.
polyoxyalkene condensates of aliphatic alcohols, whether linear- or branched-chain and unsaturated or saturated, especially ethoxylated and/or propoxylated aliphatic alcohols containing from about 6 to about 24 carbon atoms and incorporating from about 2 to about 50 ethylene oxide and/or propylene oxide units. Suitable alcohols include xe2x80x9ccoconutxe2x80x9d fatty alcohol, xe2x80x9ctallowxe2x80x9d fatty alcohol, lauryl alcohol, myristyl alcohol and oleyl alcohol.
Ethoxylated fatty alcohols may be used alone or in admixture with anionic surfactants, especially the preferred surfactants above. The average chain lengths of the alkyl group R11 in the general formula:
R11O(CH2CH2O)nH
is from 6 to 20 carbon atoms. Notably the group R11 may have chain lengths in a range from 9 to 18 carbon atoms.
The average value of n should be at least 2. The numbers of ethylene oxide residues may be a statistical distribution around the average value. However, as is known, the distribution can be affected by the manufacturing processor altered by fractionation after ethoxylation. Particularly preferred ethoxylated fatty alcohols have a group R11 which has 9 to 18 carbon atoms while n is from 2 to 8.
Also included within this category are nonionic surfactants having a formula:
wherein R12 is a linear alkyl hydrocarbon radical having an average of 6 to 18 carbon atoms, R13 and R14 are each linear alkyl hydrocarbons of about 1 to about 4 carbon atoms, x is an integer of from 1 to 6, y is an integer of from 4 to 20 and z is an integer from 4 to 25.
One preferred nonionic surfactant of the above formula is Poly-Tergent SLF-18 a registered trademark of the Olin Corporation, New Haven, Conn. having a composition of the above formula where R12 is a C6-C10 linear alkyl mixture, R13 and R14 are methyl, x averages 3, y averages 12 and z averages 16. Another preferred nonionic surfactant is
wherein R15 is a linear, aliphatic hydrocarbon radical having from about 4 to about 18 carbon atoms including mixtures thereof; and R16 is a linear, aliphatic hydrocarbon radical having from about 2 to about 26 carbon atoms including mixtures thereof; j is an integer having a value of from 1 to about 3; k is an integer having a value from 5 to about 30; and l is an integer having a value of from 1 to about 3. Most preferred are compositions in which j is 1, k is from about 10 to about 20 and l is 1. These surfactants are described in WO 94/22800. Other preferred nonionic surfactants are linear fatty alcohol alkoxylates with a capped terminal group, as described in U.S. Pat. No. 4,340,766 to BASF. Particularly preferred is Plurafac LF403 ex. BASF.
Another nonionic surfactant included within this category are compounds of formula:
R17xe2x80x94(CH2CH2O)qH
wherein R17 is a C6-C24 linear or branched alkyl hydrocarbon radical and q is a number from 2 to 50; more preferably R17 is a C8-C18 linear alkyl mixture and q is a number from 2 to 15.
polyoxyethylene or polyoxypropylene condensates of alkyl phenols, whether linear- or branched-chain and unsaturated or saturated, containing from about 6 to 12 carbon atoms and incorporating from about 2 to about 25 moles of ethylene oxide and/or propylene oxide.
polyoxyethylene derivatives of sorbitan mono-, di-, and tri-fatty acid esters wherein the fatty acid component has between about 12 and about 24 carbon atoms. The preferred polyoxyethylene derivatives are of sorbitan monolaurate, sorbitan trilaurate, sorbitan monopalmitate, sorbitan tripalmitate, sorbitan monostearate, sorbitan monoisostearate, sorbital tristearate, sorbitan monooleate, and sorbitan trioleate. The polyoxyethylene chains may contain between about 4 and about 30 ethylene oxide units, preferably about 10 to about 20. The sorbitan ester derivatives contain 1, 2 or 3 polyoxyethylene chains dependent upon whether they are mono-, di- or tri-acid esters.
polyoxyethylene-polyoxypropylene block copolymers having formula:
HO(CH2CH2O)a(CH(CH3)CH2O)b(CH2CH2O)cH
or
HO(CH(CH3)CH2O)d(CH2CH2O)e(CH(CH3)CH2O)fH
wherein a, b, c, d, e and f are integers from 1 to 350 reflecting the respective polyethylene oxide and polypropylene oxide blocks of said polymer. The polyoxyethylene component of the block polymer constitutes at least about 10% of the block polymer. The material preferably has a molecular weight of between about 1,000 and about 15,000, more preferably from about 1,500 to about 6,000. These materials are well-known in the art. They are available under the trademark xe2x80x9cPluronicxe2x80x9d and xe2x80x9cPluronic Rxe2x80x9d, a product of BASF Corporation.
Alkyl Glycosides
R21O(R22O)n(Z1)p
wherein R21 is a monovalent organic radical (e.g., a monovalent saturated aliphatic, unsaturated aliphatic or aromatic radical such as alkyl, hydroxyalkyl, alkenyl, hydroxyalkenyl, aryl, alkylaryl, hydroxyalkylaryl, arylalkyl, alkenylaryl, arylalkenyl, etc.) containing from about 6 to about 30 (preferably from about 8 to 18 and more preferably from about 9 to about 13) carbon atoms; R22 is a divalent hydrocarbon radical containing from 2 to about 4 carbon atoms such as ethylene, propylene or butylene (most preferably the unit (R22O)n represents repeating units of ethylene oxide, propylene oxide and/or random or block combinations thereof); n is a number having an average value of from 0 to about 12; Z1 represents a moiety derived from a reducing saccharide containing 5 or 6 carbon atoms (most preferably a glucose unit); and p is a number having an average value of from 0.5 to about 10 preferably from about 0.5 to about 5.
Examples of commercially available materials from Henkel Kommanditgesellschaft Aktien of Dusseldorf, Germany include APG 300, 325 and 350 with R21 being C9-C11, n is 0 and p is 1.3, 1.6 and 1.8-2.2 respectively; APG 500 and 550 with R21 is C12-C13, n is 0 and p is 1.3 and 1.8-2.2, respectively; and APG 600 with R21 being C12-C14, n is 0 and p is 1.3.
While esters of glucose are contemplated especially, it is envisaged that corresponding materials based on other reducing sugars, such as galactose and mannose are also suitable.
Amine oxides having formula:
R18R19R20N=O
wherein R18, R19 and R20 are saturated aliphatic radicals or substituted saturated aliphatic radicals. Preferable amine oxides are those wherein R18 is an alkyl chain of about 10 to about 20 carbon atoms and R19 and R20 are methyl or ethyl groups or both R18 and R19 are alkyl chains of about 6 to about 14 carbon atoms and R20 is a methyl or ethyl group.
Amphoteric synthetic detergentsxe2x80x94can be broadly described as derivatives of aliphatic tertiary amines, in which the aliphatic radical may be straight chain or branched and wherein one of the aliphatic substituents contain from about 8 to about 18 carbons and one contains an anionic water-solubilizing group, i.e., carboxy, sulpho, sulphato, phosphato or phosphono. Examples of compounds falling within this definition are sodium 3-dodecylamino propionate and sodium 2-dodecylamino propane sulfonate.
Zwifterionic synthetic detergentsxe2x80x94can be broadly described as derivatives of aliphatic quaternary ammonium, phosphonium and sulphonium compounds in which the aliphatic radical may be straight chained or branched, and wherein one of the aliphatic substituents contains from about 8 to about 18 carbon atoms and one contains an anionic water-solubilizing group, e.g., carboxy, sulpho, sulphato, phosphato or phosphono. These compounds are frequently referred to as betaines. Besides alkyl betaines, alkyl amino and alkyl amido betaines are encompassed within this invention.
Particularly preferred nonionic surfactants are polyoxyethylene and polyoxypropylene condensates of linear aliphatic alcohols.
The preferred range of surfactant is from about 0.5 to about 30% by wt., more preferably from about 0.5 to about 15% by weight of the composition.
Sequestrants
The detergent compositions herein may also optionally contain one or more transition metal chelating agents. These components may also have calcium and magnesium chelation capacity, but preferentially they show selectivity to binding heavy metal ions. Such chelating agents can be selected from the group consisting of amino carboxylates, amino phosphonates, polyfunctionally-substituted aromatic chelating agents and mixtures therein. Without intending to be bound by theory, it is believed that the benefit of these materials is due in part to their exceptional ability to remove iron and manganese ions from washing solutions by formation of soluble chelates.
Amino carboxylates useful as optional chelating agents include ethylenediaminetetraacetates, N-hydroxyethylethylenediaminetriacetates, nitrilotriacetates, ethylenediamine tetraproprionates, triethylenetetraaminehexaacetates, diethylenetriaminepentaacetates, ethylenediamine disuccinate, and ethanoldiglycines, alkali metal, ammonium, and substituted ammonium salts therein and mixtures therein.
Amino phosphonates are also suitable for use as chelating agents in the compositions of the invention when at least low levels of total phosphorus are permitted in detergent compositions, and include ethylenediaminetetrakis (methylenephosphonates) and diethylenetriaminepentakis (methylenephosphonates). Preferably, these amino phosphonates do not contain alkyl or alkenyl groups with more than about 6 carbon atoms.
Polyfunctionally-substituted aromatic chelating agents are also useful in the compositions herein. See U.S. Pat. No. 3,812,044, issued May 21, 1974, to Connor et al. Preferred compounds of this type in acid form are dihydroxydisulfobenzenes such as 1,2-dihydroxy-3,5-disulfobenzene.
If utilized, these chelating agents will generally comprise from about 0.1% to about 10% by weight of the detergent compositions herein. More preferably, if utilized, the chelating agents will comprise from about 0.1% to about 5.0% by weight of such composition.
Anti-Scalants
Scale formation on dishes and machine parts can be a significant problem. It can arise from a number of sources but, primarily it results from precipitation of either alkaline earth metal carbonates, phosphates or silicates. Calcium carbonate and phosphates are the most significant problem. To reduce this problem, ingredients to minimize scale formation can be incorporated into the composition. These include polyacrylates of molecular weight from 1,000 to 400,000 examples of which are supplied by Rohm and Haas, BASF and Alco Corp. and polymers based on acrylic acid combined with other moieties. These include acrylic acid combined with maleic acid, such as Sokalan CP5 and CP7 supplied by BASF or Acusol 479N supplied by Rohm and Haas; with methacrylic acid such as Colloid 226/35 supplied by Rhone-Poulenc; with phosphonate such as Casi 773 supplied by Buckman Laboratories; with maleic acid and vinyl acetate such as polymers supplied by Hxc3xcls; with acrylamide; with sulfophenol methallyl ether such as Aquatreat AR 540 supplied by Alco; with 2-acrylamido-2-methylpropane sulfonic acid such as Acumer 3100 supplied by Rohm and Haas or such as K-775 supplied by Goodrich; with 2-acrylamido-2-methylpropane sulfonic acid and sodium styrene sulfonate such as K-798 supplied by Goodrich; with methyl methacrylate, sodium methallyl sulfonate and sulfophenol methallyl ether such as Alcoperse 240 supplied by Alco; polymaleates such as Belclene 200 supplied by FMC; polymethacrylates such as Tamol 850 from Rohm and Haas; polyaspartates; ethylenediamine disuccinate; organo polyphosphonic acids and their salts such as the sodium salts of aminotri(methylenephosphonic acid) and ethane 1-hydroxy-1,1-diphosphonic acid. The anti-scalant, if present, is included in the composition from about 0.05% to about 10% by weight, preferably from 0.1% to about 5% by weight, most preferably from about 0.2% to about 5% by weight.
Corrosion Inhibitors
The composition my optionally contain corrosion inhibitors to reduce the tarnishing of silver flatware. Such inhibitors include benzotriazole and other members of the azole family. Particularly preferred are azoles, including imidazoles. Additional antitarnish additives include water-soluble bismuth compounds such as bismuth nitrate as taught in GB 2,297,096 A; heavy metal salts of copper, iron, manganese, zinc, or titanium (EP 0 636 688 A1, GB 2,283,494 A); paraffin oil; and non-paraffin oil organic agents such as fatty esters of mono or polyhydridic alcohols as claimed in EP 0 690 122 A2.
Antifoams
The compositions, when formulated for use in machine dishwashing compositions, preferably include an antifoam system. Suitable antifoam systems for use herein may include essentially any known antifoam compound, including, for example, silicone antifoams, silicone oil, mono- and distearyl acid phosphates, mineral oil, and 2-alkyl and alcanol antifoam compounds. Even if the machine dishwashing composition contains only defoaming surfactants, the antifoam assists to minimize foam which food soils can generate. The compositions may include 0.02 to 2% by weight of antifoam, preferably, 0.05 to 1.0%.
The machine dishwashing compositions disclosed herein can be formulated in any desirable form such as powders, granulates, pastes, liquids, gels, solids or tablets. As an example, the process of preparing a granulate may involve preparing a slurry of the ingredients identified above and drying the mixture by means of suitable equipment such as a turbine dryer (Turbogranulation dryer ex Vomm-Turbo Technology, Vomm Impianti E Processi SrL, Milan, Italy). Also, the process may involve preparing the slurry, spray-drying the slurry by conventional techniques using a spray tower in which the slurry is atomized and dried in a hot air stream, followed by restructuring the resulting powder, optionally after milling, in a granulation process (Lxc3x6dige recycler and Lxc3x6dige plow shear). In a particularly preferred process, the slurry is sprayed onto fine (recycled) particles and then dried to form gradually growing co-granules. Another attractive possibility is to dry the slurry in a rotary drum granulator and to spray slurry onto recirculated fines, thus building up coarser particles. These particles are either simultaneously or subsequently dried to give a co-granule with a more homogeneous moisture distribution than those obtained by use of a turbine dryer.
The process of preparing a tablet may involve admixing the ingredients identified above, transferring the mixture to the tablet die, and compressing with a compaction pressure from about of 3xc3x97106 kg/m2 to about 3xc3x97107 kg/m2. It may be preferable to pre-granulate some or all of the ingredients, optionally with surfactant to enhance dissolution, to give granulates of size 100-2000 microns and mix these together with any remaining material prior to compaction. Another possibility is to pre-coat the granulate with any liquid component of the composition via, for example, a fluid bed, pan coater or rolling drum to give encapsulates. The encapsulates are then compressed with a compaction pressure from about 1xc3x97106 kg/m2 to about 3xc3x97107 kg/m2.
Machine Dishwashing Method
A preferred machine dishwashing method includes treating soiled articles selected from crockery, glassware, hollowware, silverware and cutlery and mixtures thereof, with an aqueous solution having dissolved or dispersed therein an effective amount of a machine dishwashing composition disclosed herein. By an effective amount of the machine dishwashing composition it is meant from 8 g to 60 g of the composition dissolved or dispersed in a wash solution of volume from 3 to 10 liters, as typical product dosages and wash solution volumes commonly employed in conventional machine dishwashing methods.


Pruning shears include a first arm including a first handle and a jaw including a first tab; a first blade including a cutting edge and an ear opposite the cutting edge and having a first through hole wherein the first arm and the first blade are secured together by inserting the first tab into the first through hole; a second arm including a second handle and a joining section; a second blade secured to the joining section; a pivot joint for pivotably securing the first arm to the second arm; and a torsion spring positioned between the first arm and the second arm. The torsion spring exerts an expansion force to push the first arm and the second arm apart from each other.

1. Field of Invention
The invention relates to pruning shears and more particularly to such a pair of pruning shears with improved characteristics including increased structural strength, prolonged period of use time, and being adapted to operate smoothly.
2. Description of Related Art
A conventional type of pruning shears is shown in FIG. 1. The shears have two arms 1 pivotably interconnected by means of a pivot joint (not numbered), a helical compression spring 3 positioned between the arms 1, and two cutting jaws 2 in which one jaw 2 has a notch 4. In a cutting operation, a plant material (e.g., a flower stalk, a branch, etc.) is introduced into a shear opening of the open shears and the shears are slowly closed for cutting through the material.
The provision of the notch 4 can facilitate the holding of the plant material in the shear opening. However, it also decreases the structural strength of the jaws 2. The jaws 2 are thus subject to break after a period time of use. Further, its cutting operation is not smooth because the cut plant may interfere with the arms 1.
Another conventional type of pruning shears is shown in FIG. 2. The shears have two arms 5 pivotably interconnected by means of a pivot joint (not numbered), a compression spring 7 positioned between the arms 5, and two cutting jaws 6. One jaw 6 has a through hole (not shown) and the front end of one arm 5 has a through hole 9. A fastener (e.g., screw) 8 is driven into both through holes 9 to secure the jaw 6 and the arm 5 together.
However, the provision of the through holes can decrease the structural strength of the shears. The shears are thus subject to break after a period time of use.
There have been numerous suggestions in prior patents for pruning shears. A pertinent prior art of which this inventor is aware is U.S. Pat. No. 6,634,105.
A need remains for a pair of improved pruning shears in order to contribute significantly to the advancement of the art.


A process of dyeing a molded article is disclosed. The process entails immersing at least a portion of the article in a dyeing bath, retaining the portion in the bath for a period of time sufficient to allow an amount of dye to diffuse into the article, and removing said article from the bath. The molded article comprises a polymeric resin such as (co)polyester, (co)polycarbonates, acrylonitrile-butadiene-styrene, polyamide, polyurethane, polyalkyl(meth)acrylate, allyldiglycol carbonate and styrene copolymers. The dyeing bath contains in addition to dye, water, a plasticizing agent and a leveling agent.

The present invention relates to plastic articles and more particularly to colored articles, and to a process for their preparation.
A process for tinting of articles molded from a polymeric resin is disclosed. Preferably, the article is molded from polycarbonate and the process entails immersing the molded article in a dye bath that contains
(i) at least one leveling agent,
(ii) at least one plasticizing agent and
(iii) water.
The method is especially useful in the manufacture of tinted lenses.
Articles molded of polycarbonate are well known. The utility and method for making colored articles that are prepared from pigmented polycarbonate compositions are well known. Also known are processes for dyeing articles molded of resins, including polycarbonates, and including lenses that have been tinted by immersion in special pigmenting mixtures. Among the advantages attained by such tinting of lenses, mention has been made of reduced light transmission and mitigation of glare.
U.S. Pat. No. 4,076,496 disclosed a dye bath composition suitable for dyeing hard-coated polarized lenses. The composition of the bath included a dye and as a solvent, a mixture of glycerol and ethylene glycol, optionally, with a minor proportion of water or other organic solvent.
U.S. Pat. No. 5,453,100 disclosed polycarbonate materials that are dyed by immersion into a mixture of dye or pigment dissolved in a solvent blend. The blend is made up of an impregnating solvent that attacks the polycarbonate and allows the impregnation of the dye or pigment and a moderating solvent that mitigates the attack of the impregnating solvent. The impregnating solvent thus disclosed includes at least one solvent selected from dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether and propylene glycol monomethyl ether. The moderating organic solvent includes at least one solvent selected from propylene glycol, 1,4-butane diol or ethylene glycol monobutyl ether.
PCT/CA99/00803 (WO 0014325) disclosed tinting plastic articles by immersion in an aqueous dispersion and exposing the dispersion and immersed article to microwave radiation. JP 53035831 B4 disclosed polycarbonate moldings that are dyed in aqueous dispersion containing dispersed dyes and diallyl phthalate, o-phenylphenol or benzylalcohol. Also, JP 55017156 disclosed aliphatic polycarbonate lenses that are colored with liquor containing dyes and water. JP 56031085 (JP-104863) disclosed compositions containing a disperse dye in an aliphatic ketone and polyhydric alcohol said to be useful in coloring polycarbonate films at room temperature. JP2000248476 disclosed a molded polycarbonate bolt that was dyed with a solution containing dyes, an anionic leveling agent and then treated with a solution containing thiourea dioxide.
U.S. Pat. No. 4,812,142 disclosed polycarbonate articles dyed at a temperature of 200xc2x0 F. or above in a dye solvent having a boiling point of at least 350xc2x0 F., and U.S. Pat. No. 3,514,246 disclosed immersing molded polycarbonate articles in an emulsified dye liquor which contains a water insoluble dyestuff, an oil-soluble surface active agent dissolved in an aliphatic hydrocarbon solvent and water. The procedure was repeated with similar results where the surfactant was replaced by a poly(oxyethylene) derivative. U.S. Pat. No. 3,532,454 disclosed dyeing of polycarbonate fibers with a dye composition that contains at least one of alkoxyalkylbenzyl ether, alkylene glycol di-benzyl ether, benzoic acid alkoxyalkyl ester or phenoxy acetic acid-alkoxyalkyl ester. U.S. Pat. No. 3,630,664 disclosed a dye bath that required the presence of a carbonate conforming to a specific formula, e.g., ethyl-benzyl-carbonate.
The inventive method and the dye bath composition of this invention are useful for dyeing plastic articles molded of a variety of resinous molding compositions. The suitable resins include both thermoplastic and thermosetting compositions. Among the suitable resins, mention may be made of (co)polyesters, (co)polycarbonates (including aromatic and aliphatic polycarbonate such as allyldiglycol carbonate, e.g., trade name CR-39), polyesterpolycarbonate copolymers, styrenic copolymers such as SAN and acrylonitrile-butadiene-styrene (ABS), acrylic polymers such as polymethylmethacrylate and ASA, polyamide, and polyurethane and blends of one or more of these resins. Particularly, the invention is applicable to polycarbonates, and most particularly to thermoplastic aromatic polycarbonates.
The molding compositions useful in molding the articles that are suitable for use in the inventive process may include any of the additives that are known in the art for their function in these compositions and include at least one of mold release agents, fillers, reinforcing agents in the form of fibers or flakes most notably metal flakes such as aluminum flakes, flame retardant agents, pigments and opacifying agents such as titanium dioxide and the like, light-diffusing agents such as polytetrafluoroethylene, zinc oxide, Paraloid EXL-5136 available from Rohm and Haas and crosslinked polymethylmethacrylate minispheres (such as n-licrospheres from Nagase America) UV-stabilizers, hydrolytic stabilizers and thermal stabilizers.
Articles to be dyed in accordance with the inventive process may be produced conventionally by methods that have long been practiced in the plastics arts and include articles molded by compression molding, injection molding, rotational molding, extrusion, injection and extrusion blow molding, and casting, the method of producing the articles is not critical to the practice of the inventive process. The articles may be any of a vast variety of useful items and include computer face-plates, keyboards, bezels and cellular phones, color coded packaging and containers of all types, including ones for industrial components, residential and commercial lighting fixtures and components therefor, such as sheets, used in building and in construction, tableware, including plates, cups and eating utensils, small appliances and their components, optical and sun-wear lenses, as well as decorative films including such films that are intended for use in film insert molding.
Polymer resins particularly suitable in the present context include one or a mixture of two or more resins selected from the group consisting of polyester, polycarbonate, polyesterpolycarbonate copolymer, acrylonitrile-butadiene-styrene (ABS), polyamide, polyurethane, polymethylmethacrylate and styrenic copolymer. While styrenic copolymers, most notable styrene-acrylonitrile copolymers are thus suitable, the inventive process is not applicable for tinting of homopolystyrene.
According to the present invention, the molded article to be tinted, preferably a lens, is immersed in the dyeing bath mixture for a time and at temperature sufficient to facilitate at least some impregnation, or diffusion, of the dye into the bulk of the article thus effecting tinting thereof. For tinting articles made of aromatic polycarbonate, the immersion may be carried out at a temperature of about 90 to 99xc2x0 C. and the immersion time is typically less than 1 hour, most preferably in the range of 1 to 15 minutes. However, due to the efficiency of dye up-take, thermoplastic resins that have low heat distortion temperature may be dyed at lower temperatures than polycarbonate. For example, polyurethanes and SAN may be readily dyed using the solution composition that is typically used for tinting polycarbonate, heated to only about 60xc2x0 C. and 90xc2x0 C., respectively. The tinted article is then withdrawn at a desired rate, including a rate sufficient to effect a tinting gradient, the portion of the article that remains in the mixture longest is impregnated with the most dye so that it exhibits the darkest color tint.
The dyeing bath mixture contains:
(a) water in an amount of 50 to 90, preferably 62.5 to 85, most preferably 70 to 77.5 pbw (percent by weight relative to the weight of the dyeing bath mixture);
(b) an amount of dye sufficient to effect tinting, generally 0.1 to 15, preferably 0.3 to 5, most preferably 0.4 to 2 pbw;
(c) an amount of 2.5 to 20, preferably 5 to 12.5, most preferably 7.5 to 10 pbw of at least one plasticizing agent conforming to
Rxe2x80x2xe2x80x94[(O(CH2)m)nxe2x80x94]OH
where Rxe2x80x2 is an ethyl, propyl or butyl radical,
m is 2, 3 or 4, and
n is 1, 2 or 3
with the proviso that where Rxe2x80x2 is butyl m is 2 or 4, and
(d) an amount of 5 to 30, preferably 10 to 25, most preferably 15 to 20 pbw of at least one leveling agent conforming structurally to
Hxe2x80x94[(O(CH2)m)nxe2x80x94]OH
where m is 2, 3 or 4 and
n is 1, 2, or 3.
A particularly suitable plasticizing agent is a member selected from the group consisting of ethylene glycol butyl ether, diethylene glycol ethylether, diethylene glycol butylether, propylene glycol propylether, dipropylene glycol propyl ether and tripropylene glycol propylether.
A particularly suitable leveling agent is a member selected from the group consisting of diethylene glycol, triethylene glycol and 1,4 butandiol.
The dyes to be used in accordance with the invention are conventional and include fabric dyes and disperse dyes as well as dyes that are known in the art as being suitable for tinting of polycarbonates.
Examples of suitable disperse dyes include Disperse Blue #3, Disperse Blue #14, Disperse Yellow #3, Disperse Red #13 and Disperse Red #17. The classification and designation of the dyes recited in this specification are in accordance with xe2x80x9cThe Colour Indexxe2x80x9d, 3rd Edition published jointly by the Society of Dyes and Colors and the American Association of Textile Chemists and Colorists (1971), incorporated herein by reference. Dyestuffs can generally be used either as a sole dye constituent or as a component of a dye mixture depending upon the color desired. Thus, the term dye as used herein includes dye mixture.
The dye class known as xe2x80x9cSolvent Dyesxe2x80x9d is useful in the practice of the present invention. This dye class includes the preferred dyes Solvent Blue 35, Solvent Green 3 and Acridine Orange Base. However, Solvent Dyes, in general, do not color as intensely as do Disperse Dyes.
Among the suitable dyes, special mention is made of water-insoluble azo, diphenylamine and anthraquinone compounds. Especially suitable are acetate dyes, dispersed acetate dyes, dispersion dyes and dispersol dyes such as are disclosed in Colour Index, 3rd Edition, Vol. 2, The Society of Dyers and Colourists, 1971, pp. 2479 and pp. 2187-2743, respectively, all incorporated herein by reference. The preferred dispersed dyes include Dystar""s Palanil Blue E-R150 (anthraquinone/Disperse Blue) and DIANIX Orange E-3RN (azo dye/Cl Disperse Orange 25). Note that phenol red and 4-phenylazophenol do not dye polycarbonate in accordance with the inventive process.
The dyes known as xe2x80x9cdirect dyesxe2x80x9d and the ones termed xe2x80x9cacid dyesxe2x80x9d are not suitable in the practice of the invention for polycarbonate; however, acid dyes are effective with nylon.
The amount of dye used in the mixture can vary; however, only small amounts are typically needed to sufficiently tint an article in accordance with the invention. A typical dye concentration in the bath is 0.4 pbw, but there is considerable latitude in this regard. Generally, dyes may be present in the solvent mixture at a level of about 0.1 to 15 pbw, preferably 0.3 to 0.5 pbw. Where a dye mixture is used and the rates of consumption of the individual components differ one from the others, dye components will have to be added to the bath in such a manner that their proportions in the bath remain substantially constant.
The bath may optionally include an emulsifier in amounts of up to 15 pbw, preferably 0.5 to 5, most preferably 3 to 4 pbw. A suitable emulsifier in the context of the invention is a substance that holds two or more immiscible liquids or solids in suspension (e.g., water and the carrier). Emulsifiers which may be used include ionic, non-ionic, or mixtures thereof. Typical ionic emulsifiers are anionic, including amine salts or alkali salts of carboxylic, sulfamic or phosphoric acids, for example, sodium lauryl sulfate, ammonium lauryl sulfate, lignosulfonic acid salts, ethylene diamine tetra acetic acid (EDTA) sodium salts and acid salts of amines such as laurylamine hydrochloride or poly(oxy-1,2-ethanediyl)alpha-sulfo-omega-hydroxy ether with phenol 1-(methylphenyl)ethyl derivative ammonium salts; or amphoteric, that is, compounds bearing both anionic and cationic groups, for example, lauryl sulfobetaine; dihydroxy ethylalkyl betaine; amido betaine based on coconut acids; disodium N-lauryl amino propionate; or the sodium salts of dicarboxylic acid coconut derivatives. Typical non-ionic emulsifiers include ethoxylated or propoxylated alkyl or aryl phenolic compounds, such as, octylphenoxypolyethyleneoxyethanol or poly(oxy-1,2-ethanediyl)alpha-phenyl-omega-hydroxy, styrenated. The preferred emulsifier is a mixture of C14-C18 and C16-C18 ethoxylated unsaturated fatty acids and poly(oxy-1,2-ethanediyl)alpha-sulfo-omega-hydroxy ether with phenol 1-(methylphenyl)ethyl derivative ammonium salts and poly(oxy-1,2-ethanediyl),alpha-phenyl-omega-hydroxy, styrenated.
Emulsifiers, such as disclosed in xe2x80x9cLens Prep IIxe2x80x9d, a commercial product of Brain Power International (BPI) may be used.
According to an embodiment of the present invention, an article molded of the resins suitable in accordance with the invention, preferably molded of a polycarbonate composition, is immersed in the inventive dyeing bath. To reduce processing time, while keeping evaporation losses to a minimum, some dyeing baths may be heated to temperatures below 100xc2x0 C., preferably below 96xc2x0 C. In the course of dyeing, in accordance with the present invention, it is preferred that the dyeing bath is at a temperature below that at which the bath is at the state of ebullition. The optimum temperature of the bath is to some degree influenced by the molecular weight of the polycarbonate, its additives and the chemical nature of the dye.
In a preferred embodiment in the tinting of parts made of polycarbonate, a dye that is known to be suitable for compounding with polycarbonate composition is mixed with the plasticizer and leveling agent and water and the optional surfactant to form a dye-bath mixture. In accordance with the invention, the article is immersed in the dyeing bath and withdrawn after only a few minutes to provide a color-tinted product. The length of time in which the article should remain immersed in the bath and the process conditions depends upon the desired degree of tint.
Naturally, higher concentrations of dye and higher temperatures will increase the rate of dyeing.
In order to impart a graded tint, the molded article may be immersed in the dyeing bath and then slowly withdrawn therefrom. A graded tint results because the portion of the article that remains in the mixture longest is impregnated with the most dye.
The present invention may be more fully understood with reference to the examples set forth below. The examples are in no way to be considered as limiting, but instead are provided as illustrative of the invention.